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Sample records for high tc composite

  1. A study of high {Tc} superconducting ceramic/metal alloy composites

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, M.G.; Du, J.; Lee, R.M; Unsworth, J.; Hely, J.; Hodges, J. [Univ. of Technology, Sydney (Australia). Dept. of Materials Science

    1995-09-01

    High-{Tc} superconducting ceramic YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}/metal alloy composites were fabricated. The metal matrix was a low melting point alloy of bismuth, lead, tin, cadmium and indium. The structure, DC electrical resistivity, AC magnetic susceptibility, levitation and mechanical strength of the composites were investigated. The influence of filler content on these properties was also studied. The composites behaved as a typical metal with the resistivity increasing with temperature increase and, further, did not undergo the characteristic superconducting transition to zero resistance that is obtained with the ceramic superconductor. On the other hand, the diamagnetic properties of the superconducting ceramic were preserved in the composites. The values of diamagnetic susceptibility and levitation force increase with the volume fraction of the superconducting material. The flexural strength of the composites is improved significantly in comparison with the ceramic superconductor.

  2. High-Tc SQUID biomagnetometers

    Science.gov (United States)

    Faley, M. I.; Dammers, J.; Maslennikov, Y. V.; Schneiderman, J. F.; Winkler, D.; Koshelets, V. P.; Shah, N. J.; Dunin-Borkowski, R. E.

    2017-08-01

    In this paper, we review the preparation technology, integration in measurement systems and tests of high-Tc superconducting quantum interference devices (SQUIDs) intended for biomagnetic applications. A focus is on developments specific to Forschungszentrum Jülich GmbH, Chalmers University of Technology, MedTech West, and the University of Gothenburg, while placing these results in the perspective of those achieved elsewhere. Sensor fabrication, including the deposition and structuring of epitaxial oxide heterostructures, materials for substrates, epitaxial bilayer buffers, bicrystal and step-edge Josephson junctions, and multilayer flux transformers are detailed. The properties of the epitaxial multilayer high-Tc direct current SQUID sensors, including their integration in measurement systems with special electronics and liquid nitrogen cryostats, are presented in the context of biomagnetic recording. Applications that include magnetic nanoparticle based molecular diagnostics, magnetocardiography, and magnetoencephalography are presented as showcases of high-Tc biomagnetic systems. We conclude by outlining future challenges.

  3. Forming high-Tc superconductors. Vormgeving hoge-Tc-supergeleiders

    Energy Technology Data Exchange (ETDEWEB)

    Rabou, L.P.L.M.; Roskam, A.; Smit, H.C.D.; Veringa, H.J.

    1990-12-01

    Within the framework of the National Research Program High-Tc Superconductors the Netherlands Energy Research Foundation carried out research on the title subject by means of ceramic techniques. The aim is to manufacture bulk superconductors formed as a wire, plate or as a pipe. First the preparation of YBa{sub 2}Cu{sub 3}O{sub 7} related compounds and BiCaSrCuO by means of citrate pyrolysis and some other preparation methods are discussed. Also an overview is given of the mechanical and temperature treatment, and the analyses of the powders. Then attention is paid to the ceramic forming techniques of YBa{sub 2}Cu{sub 3}O{sub 7}: pressing (uniaxial, cold isostatic), tape casting, extrusion, slip casting and plasma spraying. 16 figs., 6 refs., 10 tabs.

  4. New superconductors from granular to high T$_{c}$

    CERN Document Server

    Deutscher, Guy

    2006-01-01

    How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This book aims to give some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a maximum of their critical temperature near the metal-insulator transition.

  5. New superconductors from granular to high T$_{c}$

    CERN Document Server

    Deutscher, Guy

    2017-01-01

    How new are the high Tc superconductors, as compared to the conventional low Tc ones? In what sense are these oxides different from regular metals in their normal state? How different is the mechanism for high Tc superconductivity from the well-known electron-phonon interaction that explains so well superconductivity in metals and alloys? What are the implications of the new features of the high Tc oxides for their practical applications? This interesting book aims to provide some answers to those questions, drawing particularly on similarities between the high Tc oxides and granular superconductors, which also present a short coherence length, a small superfluid density and an inhomogeneous structure.

  6. Mechanical Properties of TC4 Matrix Composites Prepared by Laser Cladding

    Directory of Open Access Journals (Sweden)

    WANG Lin

    2017-06-01

    Full Text Available In order to improve the penetration performance of TC4, the direct laser deposition technology was used to prepare TC4 composite material. TA15+30% TiC powder, TA15+20%Cr3C2 powder and TA15+15%B4C powder were used as deposited materials for TC4 matrix. The micromorphology, change of hardness of the deposited coating and mechanical properties of the three composites were studied. The experimental results demonstrate that the TC4 matrix with the three kinds of materials can form a complete metallurgical bonding, and the strength of TC4-(TA15+TiC, TC4-(TA15+Cr3C2 and TC4-(TA15+B4C are higher than that of TC4 matrix materials, while the plasticity is slightly worse.

  7. Proximity Effect at Graphene - High Tc Superconductor Junctions

    Science.gov (United States)

    Wang, Da; Shih, En-Min; Arefe, Ghidewon; Kim, Youngduck; Edelberg, Drew; Andrade, Erick; Wang, Dennis; Hone, James; Dean, Cory; Pasupathy, Abhay; Department of Physics, Columbia University, New York, NY 10027, USA Collaboration

    The proximity effect is a well-known mesoscopic phenomenon where Cooper pairs from a superconductor (S) enter into a normal metal (N) that is well coupled to it. Since graphene was discovered a decade ago, the proximity effect at superconductor-graphene junctions has been extensively studied and interesting phenomena such as specular Andreev reflection and ballistic transport at graphene Josephson junctions have been observed. However, superconductors used in these experiments to date are of conventional low Tc, such as aluminum(Tc=1.2K), NbSe2(Tc=7K), and MoRe(Tc=8K). Understanding how the proximity effect works between high-Tc superconductors (pnictides and cuprates) and the Dirac Fermions of graphene remains largely unexplored. The chief technical challenge here is to create high-quality junctions between high-Tc superconductors and graphene. In this work, we will introduce a home-made setup that allows us to exfoliate, transfer and encapsulate superconductor-graphene junctions in a well controlled inert atmosphere. Transport measurements of the proximity effect at graphene-iron pnictide(FeSe, FeTeSe) and graphene-cuprate(BSCCO) junctions will be described.

  8. Infrared detection with high-[Tc] bolometers and response of Nb tunnel junctions to picosecond voltage pulses

    Energy Technology Data Exchange (ETDEWEB)

    Verghese, S.

    1993-05-01

    Oxide superconductors with high critical temperature [Tc] make sensitive thermometers for several types of infrared bolometers. The authors built composite bolometers with YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta

  9. Magnetically-related properties of bismuth containing high Tc superconductors

    Science.gov (United States)

    Vezzoli, Gary C.; Chen, M. F.; Craver, F.; Safari, A.; Moon, B. M.; Lalevic, B.; Burke, Terence; Shoga, M.

    1990-08-01

    The effect of magnetic fields to 15 T on electrical resistance has been measured for the BiSrCaCuO superconductor at precise temperatures during the transition to the superconducting state from pre-onset conditions to essentially zero resistance conditions. The results show that the temperature at which the magnetic field causes a divergence in the resistance versus 1000/ T curve is approximately the same temperature as the value at which, during cooling, the positive Hall coefficient begins its abrupt descent to zero. This temperature gives the best measure of Tc. It is also shown that small oscillations of low frequency start near onset conditions, the amplitude of which at a given temperature is B-field dependent. Additionally, Hall effect studies as a function of temperature at 4 T in three separate experiments (including high Tc BiSrCaCu PbO of > 90% theoretical density) show that sharp delta-function-like peaks in + RH are observed near Tc and are superimposed on a broader maximum. The Hall data are explicable in terms of exciton formation and ionization. The bound holes associated with these excitons are believed to be the mediators producing Cooper-pairing, and scale very well with Tc for all the known high Tc oxides.

  10. Modal bifurcation in a high-Tc superconducting levitation system

    Science.gov (United States)

    Taguchi, D.; Fujiwara, S.; Sugiura, T.

    2011-05-01

    This paper deals with modal bifurcation of a multi-degree-of-freedom high-Tc superconducting levitation system. As modeling of large-scale high-Tc superconducting levitation applications, where plural superconducting bulks are often used, it can be helpful to consider a system constituting of multiple oscillators magnetically coupled with each other. This paper investigates nonlinear dynamics of two permanent magnets levitated above high-Tc superconducting bulks and placed between two fixed permanent magnets without contact. First, the nonlinear equations of motion of the levitated magnets were derived. Then the method of averaging was applied to them. It can be found from the obtained solutions that this nonlinear two degree-of-freedom system can have two asymmetric modes, in addition to a symmetric mode and an antisymmetric mode both of which also exist in the linearized system. One of the backbone curves in the frequency response shows a modal bifurcation where the two stable asymmetric modes mentioned above appear with destabilization of the antisymmetric mode, thus leading to modal localization. These analytical predictions have been confirmed in our numerical analysis and experiments of free vibration and forced vibration. These results, never predicted by linear analysis, can be important for application of high-Tc superconducting levitation systems.

  11. Neutron depolarization effects in a high-Tc superconductor (abstract)

    Science.gov (United States)

    Nunes, A. C.; Pickart, S. J.; Crow, L.; Goyette, R.; McGuire, T. R.; Shinde, S.; Shaw, T. M.

    1988-11-01

    Using the polarized beam small-angle neutron scattering spectrometer at the Rhode Island Nuclear Science Center Reactor, we have observed significant depolarization of a neutron beam by passage through polycrystalline high-Tc superconductors, specifically 123 Y-Ba-Cu-O prepared and characterized at the IBM Watson Research Center. We believe that this technique will prove useful in studying aspects of these materials, such as the penetration depth of shielding currents, the presence and structure of trapped flux vortices, and grain size effects on the supercurrent distribution in polycrystalline samples. The two samples showed sharp transitions at 87 and 89 K, and have been studied at temperatures of 77 K; the second sample has also been studied at 4 K. The transition to the superconducting state was monitored by the shift in resonant frequency of a coil surrounding the sample. No measurable depolarization was observed in either sample at 77 K in both the field-cooled and zero-field-cooled states, using applied fields of 0 (nominal), 54, and 1400 Oe. This negative result may be connected with the fact that the material is still in the reversible region as indicated by susceptibility measurements, but it allows an estimate of the upper bound of possible inhomogeneous internal fields, assuming a distance scale for the superconducting regions. For the 10-μm grain size suggested by photomicrographs, this upper bound for the field turns out to be 1.2 kOe, which seems reasonable. At 4 K a significant depolarization was observed when the sample was cooled in low fields and a field of 1400 Oe was subsequently applied. This result suggests that flux lines are penetrating the sample. Further investigations are being carried out to determine the field and temperature dependence of the depolarization, and attempts will be made to model it quantitatively in terms of possible internal field distributions. We are also searching for possible diffraction effects from ordered vortex

  12. Microstructures and critical currents in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Masaki

    1998-11-01

    Microstructural defects are the primary determining factors for the values of critical-current densities in a high {Tc} superconductor after the electronic anisotropy along the a-b plane and the c-direction. A review is made to assess firstly what would be the maximum achievable critical-current density in YBa{sub 2}Cu{sub 3}O{sub 7} if nearly ideal pinning sites were introduced and secondly what types of pinning defects are currently introduced or exist in YBa{sub 2}Cu{sub 3}O{sub 7} and how effective are these in pinning vortices.

  13. International Discussion Meeting on High-Tc Superconductors

    CERN Document Server

    1988-01-01

    In the past two years conferences on superconductivity have been characterized by the attendance of hundreds of scientists. Consequently, the organizers were forced to schedule numerous parallel sessions and poster presentations with an almost unsurveyable amount of information. It was, therefore, felt that a more informal get-together, providing ample time for a thourough discussion of some topics of current interest in high-temperature superconductivity, was timely and benefitial for leading scientists as well as for newcomers in the field. The present volume contains the majority of papers presented at the International Discussion Meeting on High-Tc Superconductors held at the Mauterndorf Castle in the Austrian Alps from February 7 to 11, 1988. Each subject was introduced in review form by a few invited speakers and then discussed together with the contributed poster presentations. These discussion sessions chaired by selected scientists turned out to be the highlights of the meeting, not only because all ...

  14. The first five years of high- Tc superconductivity

    Science.gov (United States)

    Müller, K. Alex

    1991-12-01

    After the 1986 discovery and confirmation of superconductivity in doped La 2CuO 4, a “gold rush” occurred in the following year when the transition temperature in YBa 2Cu 3O 7-δ exceeded the boiling point of liquid nitrogen. In 1988, even higher Tc's were reported in new compounds without rare-earth ions. The preparation techniques started to be improved substantially and results on scholarly conducted experiments became available. Since then, the data obtained with different techniques fitted together like pieces of a puzzle, and continue to do so. Early in 1987, high critical magnetic fields and currents were reported in epitaxial films and single crystals. This opened the way for application-oriented research and has led to first true successes in 1990/91. The following is a near verbal transcript of my presentation.

  15. Doping dependence of fluctuation diamagnetism in high Tc superconductors

    Science.gov (United States)

    Sarkar, Kingshuk; Banerjee, Sumilan; Mukerjee, Subroto; Ramakrishnan, T. V.

    2016-02-01

    Using a recently proposed Ginzburg-Landau-like lattice free energy functional due to Banerjee et al. (2011) we calculate the fluctuation diamagnetism of high-Tc superconductors as a function of doping, magnetic field and temperature. We analyse the pairing fluctuations above the superconducting transition temperature in the cuprates, ranging from the strong phase fluctuation dominated underdoped limit to the more conventional amplitude fluctuation dominated overdoped regime. We show that a model where the pairing scale increases and the superfluid density decreases with underdoping produces features of the observed magnetization in the pseudogap region, in good qualitative and reasonable quantitative agreement with the experimental data. In particular, we explicitly show that even when the pseudogap has a pairing origin the magnetization actually tracks the superconducting dome instead of the pseudogap temperature, as seen in experiment. We discuss the doping dependence of the 'onset' temperature for fluctuation diamagnetism and comment on the role of vortex core-energy in our model.

  16. Plasma resonance in anisotropic layered high-Tc superconductors

    DEFF Research Database (Denmark)

    Sakai, Shigeki; Pedersen, Niels Falsig

    1999-01-01

    The plasma resonance is described theoretically by the inductive coupling model for a large stacked Josephson-junction system such as the intrinsic Josephson-junction array in anisotropic high- T-c superconductors. Eigenmodes of the plasma oscillation are analytically described and a numerical...... example for the large stack case N=50 is given. The scaling length characteristic of each mode is discussed. Numerical results for the plasma resonance for N= 50 in the presence of an external rf drive with wave number k are given. For k different from zero possible resonance modes among the eigen...... oscillation modes are shown, and it is further demonstrated that for k=0 the resonance takes place as a collection of N independent resonant Josephson junctions. Some guidelines for possible experiments are shown. It is also shown that, very recent microwave experiments for the plasma resonance can...

  17. Present and future wire fabrication techniques for high {Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Jin, S. [AT and T Bell Labs., Murray Hill, NJ (United States)

    1994-12-31

    Fabrication of high-J{sub c},, long-length conductors is essential for successful applications of the high {Tc} superconductors. Several different approaches for high-J{sub c} wire fabrications have been demonstrated, however, none of them meets all the requirements in terms of desirable length, critical currents, and operating temperature ranges. High-J{sub c} YBCO wires have been made only in length less than a meter. The BSCCO wires/ribbons exhibit high J{sub c} and can be made long but they are not particularly useful for major applications above {approximately}30K. For TBCCO, neither high-J{sub c} long wire comparable to BSCCO material nor sufficient flux pinning comparable to YBCO has been demonstrated, even with the promising single Tl-O layered compound. This paper describes various microstructural and processing problems limiting the development of desirable long-length superconductors, and discusses some alternative approaches that may be utilized to overcome the problems.

  18. Dynamic resistance of a high-Tc superconducting flux pump

    Science.gov (United States)

    Jiang, Zhenan; Hamilton, K.; Amemiya, Naoyuki; Badcock, R. A.; Bumby, C. W.

    2014-09-01

    Superconducting flux pumps enable large currents to be injected into a superconducting circuit, without the requirement for thermally conducting current leads which bridge between the cryogenic environment and room temperature. In this work, we have built and studied a mechanically rotating flux pump which employs a coated conductor high-Tc superconducting (HTS) stator. This flux pump has been used to excite an HTS double pancake coil at 77 K. Operation of the flux pump causes the current within the superconducting circuit to increase over time, before saturating at a limiting value. Interestingly, the superconducting flux pump is found to possess an effective internal resistance, Reff, which varies linearly with frequency, and is two orders of magnitude larger than the measured series resistance of the soldered contacts within the circuit. This internal resistance sets a limit for the maximum achievable output current from the flux pump, which is independent of the operating frequency. We attribute this effect to dynamic resistance within the superconducting stator wire which is caused by the interaction between the DC transport current and the imposed alternating magnetic field. We provide an analytical expression describing the output characteristics of our rotating flux pump in the high frequency limit, and demonstrate that it describes the time-dependent behavior of our experimental circuit. Dynamic resistance is highlighted as a generic issue that must be considered when optimizing the design of an HTS flux pump.

  19. Magnetic Anisotropy in A High-Tc Superconductor YBa2Cu3O7-δ Single Crystal below Tc

    Science.gov (United States)

    Isikawa, Yosikazu; Mori, Katsunori; Kobayashi, Koichi; Sato, Kiyoo

    1988-03-01

    We have measured the magnetic field dependence of magnetization of single-crystal YBa2Cu3O7-δ in detail in fields up to 5 kOe in the temperature range below Tc, i.e., 93 K. Lower critical fields, Hc1’s, at which the magnetization deviates from linearity, are very anisotropic; Hc1\\bot(0) (perpendicular to the ab-plane) is 305 Oe and Hc1\\varparallel(0) (parallel to the ab-plane) is 104 Oe. Both Hc1\\bot and Hc1// decrease linearly with increasing temperature up to about Tc. It is suggested that random oxygen defects in the Cu-O planes and chains are important for the high-Jc type II superconductor YBa2Cu3O7-δ.

  20. On the application of High-Tc superconductors in power coils and transformers

    NARCIS (Netherlands)

    Chevtchenko, O.A.

    2002-01-01

    In this study, the electro-magnetic properties of high-Tc tapes and coils are investigated. The focus is on Bi-2223/Ag tapes with non-twisted superconducting filaments as these are the only high-Tc superconductors at present available in sufficient length for practical applications. The study is

  1. Observing the fluctuating stripes in high-Tc superconductors

    Science.gov (United States)

    Cvetkovic, V.; Nussinov, Z.; Mukhin, S.; Zaanen, J.

    2008-01-01

    Superfluids and superconductors have been around for a long time and their explanation in terms of the Bogoliubov theory for bosons and the BCS theory for fermions belong to the highlights of twentieth century physics. However, it appears that these theories are too primitive to address the high-Tc superconductivity found in copper oxides. These electron systems seem to behave more like a dense, strongly correlated liquid contrasting markedly with the conventional quantum gasses: these show strong dynamical correlations on mesoscopic length and time scales associated with stripes, a particular form of electron crystallization. Resting on the gauge theory of topological quantum melting in 2+1 dimensions relevant for the cuprates, we describe the limit which is exactly opposite to the gas limit: the superconductor with the maximum possible amount of transient translational order. We predict that in this "orderly limit" an extra collective mode appears, and this "massive shear photon" can be regarded as a universal fingerprint of the fluctuating stripes. This mode is visible in the electrodynamic response and the ramification of our theory is that electron energy loss spectroscopy can be employed to prove or disprove the existence of dynamical stripes in cuprate superconductors.

  2. Ultrafine processing of (TiB+TiC)/TC18 composites processed by ECAP via Bc route

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liqiang; Wang, Xueting [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Lai-Chang [School of Engineering, Faculty of Computer, Health and Science, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia); Lu, Weijie, E-mail: luweijie@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-10-01

    Equal channel angular pressing provides a convenient approach to introduce ultrafine grain size into commonly used metallic materials. In this study, equal channel angular pressing of (TiB+TiC)/TC18 composite was carried out under different passes via route Bc. Microstructure evolution is systematically investigated by optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results show that grain boundary sliding contributes much to the plastic deformation and grains are refined largely to 100 nm for (TiB+TiC)/TC18 with 0.2% B{sub 4}C addition after two passes. The appearance of dislocation accelerates the transformation of spherical α recrystallized grains. Sufficient recrystallization is obtained after three passes. Tensile tests show that both high strength and elongation appear in the specimen with 0.2 wt% B{sub 4}C addition, which is deformed repeatedly after three passes. Equal channel angular pressing thus be a viable mode for producing titanium matrix composite with both high strength and ductibility.

  3. Thermophysical properties of Almahata Sitta meteorites (asteroid 2008 TC3) for high-fidelity entry modeling

    Science.gov (United States)

    Loehle, Stefan; Jenniskens, Peter; Böhrk, Hannah; Bauer, Thomas; Elsäßer, Henning; Sears, Derek W.; Zolensky, Michael E.; Shaddad, Muawia H.

    2017-02-01

    Asteroid 2008 TC3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high-fidelity re-entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation (T 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC3: a thick flat-faced ureilite suitably shaped for emissivity measurements and a thin flat-faced EL6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3-D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10-5 K-1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage.

  4. Feshbach shape resonance for high Tc pairing in superlattices of quantum stripes and quantum wells

    Directory of Open Access Journals (Sweden)

    A Bianconi

    2006-09-01

    Full Text Available   The Feshbach shape resonances in the interband pairing in superconducting superlattices of quantum wells or quantum stripes is shown to provide the mechanism for high Tc superconductivity. This mechanism provides the Tc amplification driven by the architecture of material: superlattices of quantum wells (intercalated graphite or diborides and superlattices of quantum stripes (doped high Tc cuprate perovskites where the chemical potential is tuned to a Van Hove-Lifshitz singularity (vHs in the electronic energy spectrum of the superlattice associated with the change of the Fermi surface dimensionality in one of the subbands.

  5. Plasma resonance and flux dynamics in layered high-Tc superconductors

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sakai, S.

    2000-01-01

    Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments.......Flux dynamics of layered high Tc superconductors are considered with special emphasis on the small oscillation modes. In particular we find the dispersion relation for the plasma modes and discuss the spectra to be observed in microwave experiments....

  6. The gradient crystalline structure and microhardness in the treated layer of TC17 via high energy shot peening

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huimin [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Liu, Yingang, E-mail: lygsuper1987@163.com [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Miaoquan, E-mail: honeymli@nwpu.edu.cn [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Liu, Hongjie [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China)

    2015-12-01

    Graphical abstract: - Highlights: • The gradient nanocrystalline structure was induced in treated layer of TC17. • The thickness of nanograin layer with an average grain size of 10.5 nm was 20 μm. • The composition of the treated layer of TC17 was discussed. • The gradient variation of the microhardness was obtained in treated layer of TC17. - Abstract: The gradient nanocrystalline structure from the topmost surface to the matrix of a bulk coarse-grained TC17 was attained by using high energy shot peening treatment at an air pressure of 0.35 MPa and a processing duration of 30 min. The thickness from the topmost surface with a grain size of about 10.5 nm to the matrix with a micrometer structure was about 120 μm, and the thickness in the nanocrystalline layer was about 20 μm. The microscopic and nanocrystalline structure characteristic in the treated layer were investigated via X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The nanograins layer, the nanometer-thick laminated structure layer, the refined grains layer and the low-strain matrix layer occurred in sequence from the topmost surface to the matrix, and therefore the gradient nanocrystalline structure in the treated layer was produced by using high energy shot peening. TEM investigation confirmed that the dislocation activity with very high stacking fault energy induced by surface severe plastic deformation mainly controlled the grain refinement. The microhardness (HV{sub 0.02}) from the topmost surface to the matrix gradually increased by 43% from 440 to 629 and the gradient variation of the microhardness with the depths from the topmost surface to the matrix of treated TC17 was obtained.

  7. Fabrication of multifunctional CaP-TC composite coatings and the corrosion protection they provide for magnesium alloys.

    Science.gov (United States)

    Tan, Cui; Zhang, Xiaoxu; Li, Qing

    2017-08-28

    Two major problems with magnesium (Mg) alloy biomaterials are the poor corrosion resistance and infection associated with implantation. In this study, a novel calcium phosphate (CaP)/tetracycline (TC) composite coating for Mg implants that can both improve the corrosion resistance of Mg and release a drug in a durable way is reported. Scanning electron microscope (SEM) images showed that TC additives make the CaP coating more compact and uniform. Electrochemical tests indicated CaP/TC coatings can provide excellent corrosion protection for Mg alloy substrates. Besides, TC additives can also provide effective prevention of bone infection and inflammation due to its broad-spectrum antibacterial properties. The one-step hydrothermal process reported here greatly simplified the multi-step fabrication of smart coatings reported previously.

  8. Superconducting fluctuations and pseudogap in high-Tc cuprates

    Directory of Open Access Journals (Sweden)

    Alloul H.

    2012-03-01

    Full Text Available Large pulsed magnetic fields up to 60 Tesla are used to suppress the contribution of superconducting fluctuations (SCF to the ab-plane conductivity above Tc in a series of YBa2Cu3O6+x. These experiments allow us to determine the field Hc’(T and the temperature Tc’ above which the SCFs are fully suppressed. A careful investigation near optimal doping shows that Tc’ is higher than the pseudogap temperature T*, which is an unambiguous evidence that the pseudogap cannot be assigned to preformed pairs. Accurate determinations of the SCF contribution to the conductivity versus temperature and magnetic field have been achieved. They can be accounted for by thermal fluctuations following the Ginzburg-Landau scheme for nearly optimally doped samples. A phase fluctuation contribution might be invoked for the most underdoped samples in a T range which increases when controlled disorder is introduced by electron irradiation. Quantitative analysis of the fluctuating magnetoconductance allows us to determine the critical field Hc2(0 which is found to be be quite similar to Hc’ (0 and to increase with hole doping. Studies of the incidence of disorder on both Tc’ and T* allow us to to propose a three dimensional phase diagram including a disorder axis, which allows to explain most observations done in other cuprate families.

  9. Resonance of High Tc Superconducting Microstrip Patch in a Substrate-Superstrate Configuration

    Directory of Open Access Journals (Sweden)

    S. Benkouda

    2014-02-01

    Full Text Available The effect of a protecting dielectric superstrate on the resonance of a high Tc superconducting microstrip patch is investigated. The analysis approach is based on the spectral-domain method of moments in conjunction with the complex resistive boundary condition. The complex surface impedance of the superconducting thin film is determined using London’s equation and the two-fluid model of Gorter and Casimir. Numerical results show that the resonant frequency of the high Tc superconducting rectangular patch decreases monotonically with increasing superstrate thickness, the decrease being greater for high permittivity loading.

  10. Possibility of critical field enhancement due to field penetration in high-Tc sponges and thin films

    Science.gov (United States)

    Collings, E. W.; Markoworth, A. J.; Marken, K. R., Jr.

    1989-03-01

    Magnetic susceptibility measurements of a sample of sintered high-Tc ceramic superconductor of nominal composition Y1Ba2Cu3O(7-y) were conducted as a function of temperature from liquid-He temperatures to Tc. The fitted form of the susceptibility temperature dependence yielded a sample-particle size that was only a few times larger than the field-penetration depth. The particle size was much less than the grain size and commensurate with the thickness of the optical twins. The results of the enhancement studies are also discussed in the light of Bean's (1964) early experiments on Pb sponges (in this case wavelength much greater than particle size) which exhibited spectacular enhancements of Hc in association with flux trapping at or between the Pb filaments. It is predicted that it should be possible, using presently available film-deposition techniques, to produce high-Tc films possessing severalfold enhancements of H(c1) beyond the bulk value, and that, as with the Pb sponges, the magnetization loops, even when taken within what passes for the Meissner state in such materials, will be hysteretic.

  11. Low-field vortex dynamics in various high-Tc thin films

    Indian Academy of Sciences (India)

    Vortex dynamics; flux creep; high temperature superconductor; thin film; ac susceptibil- ity. PACS Nos 74.72.-h; 74.76.Bz; 74.60.Ge. 1. Introduction. Despite the predictions of fundamental new physics and intriguing vortex phenomena in high-Tc materials at very low fields [1–6], a vast majority of experimental vortex dynam-.

  12. Low noise high-Tc superconducting bolometers on silicon nitride membranes for far-infrared detection

    NARCIS (Netherlands)

    de Nivelle, M.J.M.E.; De Nivelle, M.J.M.E.; Bruijn, M.P.; de Vries, R.; Wijnbergen, J.J.; de Korte, P.A.J.; Sanchez, Stefan; Elwenspoek, Michael Curt; Heidenblut, T.; Schwierzi, B.; Michalke, W.; Steinbeiss, E.

    1997-01-01

    High-Tc GdBa2Cu3O7 – delta superconductor bolometers with operation temperatures near 89 K, large receiving areas of 0.95 mm2 and very high detectivity have been made. The bolometers are supported by 0.62 µm thick silicon nitride membranes. A specially developed silicon-on-nitride layer was used to

  13. The research on tool wear of high speed milling titanium alloy TC4

    Science.gov (United States)

    Shi, Hongliang; Wang, Zhichao; Ren, Huanhuan; Yuan, Haoteng

    2017-01-01

    In this paper, carbide cutting tools with physical vapor deposition (PVD) coating was used to high speed milling α+β phase TC4 titanium alloy. The PVD tool was used to study the process of milling TC4 titanium alloy tool wear patterns and wear mechanisms. The results showed that the PVD coating surface wear was small after cutter blade. The cutting life was long, it was suitable for processing of titanium alloy TC4, the wear of rake face was mainly adhesion wear and oxidation wear, the flank face was mainly boundary wear. That was because the adhesion wear of the rake face and the boundary wear of the flank face had a weakening effect on the cutting edge , which made the micro crack blade of the main cutting edge.

  14. Models of high-Tc superconductivity and applications to electric generators and motors

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter

    We present the Ginzburg Landau model for mesoscopic high-Tc superconductors of complex geometry. It is shown that giant vortices can form at boundary defects. The relation between total magnetic flux penetration through the superconductor and the externally applied field is established...

  15. Theoretical models of flux pinning and flux motion in high-{Tc} superconducting oxides

    Energy Technology Data Exchange (ETDEWEB)

    Welch, D.O.

    1991-12-31

    Various issues involved in the development of phenomenological models of flux pinning and motion in high-{Tc} oxides are discussed. A simplified model is presented for the critical current density and is used to examine the question of whether flux flow results from an instability due to plasticity of the flux-line array or from pin breaking.

  16. Theory of macroscopic quantum tunnelling and dissipation in high-Tc Josephson junctions

    NARCIS (Netherlands)

    Kawabata, S.; Kawabata, Shiro; Kashiwaya, Satoshi; Asano, Yasuhiro; Tanaka, Yukio; Kato, Takeo; Kato, T.; Golubov, Alexandre Avraamovitch

    2007-01-01

    We have investigated macroscopic quantum tunnelling (MQT) in in-plane high-Tc superconductor Josephson junctions and the influence of the nodal-quasiparticle and zero energy bound states (ZES) on MQT. We have shown that the presence of ZES at the interface between the insulator and the

  17. The 9th symposium of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [eds.

    1998-03-01

    This workshop was carried out on December 11 and 12, 1997, at JAERI, Tokai in a series of modification of material by irradiation in `the multi core project II of the high temperature superconducting material research` organized by Science and Technology Agency. The following is the abstract of presentations concerning basic theories, various experimental results and material improvement of the superconductivity by high energy ion irradiation. The 26 papers are indexed individually. (J.P.N.)

  18. The 11th symposium of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [eds.] [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-03-01

    This workshop was carried out on December 16 and 17, 1999, at JAERI, Tokai in a series of modification material by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by Science and Technology Agency. The following is the abstract of presentations concerning basic theories, various experimental results and material improvement of the superconductivity by high energy ion irradiation. (author)

  19. High frequency of SH3TC2 mutations in Czech HMSN I patients.

    Science.gov (United States)

    Laššuthová, P; Mazanec, R; Vondráček, P; Sišková, D; Haberlová, J; Sabová, J; Seeman, P

    2011-10-01

    Charcot-Marie-Tooth (CMT) neuropathy type 4C (CMT4C) is an autosomal recessive (AR), demyelinating neuropathy with early spine deformities caused by mutations in the SH3TC2 gene. To determine the spectrum of SH3TC2 mutations in the Czech population, the entire coding region of SH3TC2 was sequenced in 60 unrelated Czech patients. The prevalent mutation was shown to be the p.Arg954Stop. Therefore, 412 additional patients referred for CMT testing were tested for the presence of p.Arg954Stop only. Of 60 patients in whom the SH3TC2 gene was sequenced, at least one mutation was detected in 13 (21.7%) patients and biallelic pathogenic mutations were detected in 7 (11.6%) patients. Of the 412 patients tested for p.Arg954Stop, the mutation was found in 8 patients (1.94%), 6 were homozygous and 2 were heterozygous. The second causative mutation was detected by sequencing in one of the patients but not in the other. Nine novel sequence variants were detected. Their pathogenicity was further tested in silico and in control samples. Mutations in the SH3TC2 gene are a frequent cause of demyelinating hereditary neuropathy among Czech patients. In total, at least one mutation was found in 21 unrelated patients. CMT4C seems to be the most frequent type of AR CMT and one of the most frequent of all CMT types. Mutation p.Arg954Stop is highly prevalent in the Czech population. Patients with demyelinating neuropathy along with non-dominant mode of inheritance and negative for CMT1A/hereditary neuropathy with liability to pressure palsy should be tested for the presence of the p.Arg954Stop mutation or other mutations in the SH3TC2 gene. © 2011 John Wiley & Sons A/S.

  20. Magnetic forces in high-Tc superconducting bearings

    Science.gov (United States)

    Moon, F. C.

    1991-01-01

    In September 1987, researchers at Cornell levitated a small rotor on superconducting bearings at 10,000 rpm. In April 1989, a speed of 120,000 rpm was achieved in a passive bearing with no active control. The bearing material used was YBa2Cu307. There is no evidence that the rotation speed has any significant effect on the lift force. Magnetic force measurements between a permanent rare-earth magnet and high T(sub c) superconducting material versus vertical and lateral displacements were made. A large hysteresis loop results for large displacements, while minor loops result for small displacements. These minor loops seem to give a slope proportional to the magnetic stiffness, and are probably indicative of flux pinning forces. Experiments of rotary speed versus time show a linear decay in a vacuum. Measurements of magnetic dipole over a high-T(sub c) superconducting disc of YBCO show that the lateral vibrations of levitated rotors were measured which indicates that transverse flux motion in the superconductor will create dissipation. As a result of these force measurements, an optimum shape for the superconductor bearing pads which gives good lateral and axial stability was designed. Recent force measurements on melt-quench processed superconductors indicate a substantial increase in levitation force and magnetic stiffness over free sintered materials. As a result, application of high-T(sub c) superconducting bearings are beginning to show great promise at this time.

  1. The unusually high Tc in rare-earth-doped single crystalline CaFe2As2

    Science.gov (United States)

    Wei, Fengyan; Lv, Bing; Deng, Liangzi; Meen, James K.; Xue, Yu-Yi; Chu, Ching-Wu

    2014-08-01

    In rare-earth-doped single crystalline CaFe2As2, the mysterious small volume fraction which superconducts up to 49 K, much higher than the bulk Tc ~ 30 s K, has prompted a long search for a hidden variable that could enhance the Tc by more than 30% in iron-based superconductors of the same structure. Here we report a chemical, structural and magnetic study of CaFe2As2 systematically doped with La, Ce, Pr and Nd. Coincident with the high Tc phase, we find extreme magnetic anisotropy, accompanied by an unexpected doping-independent Tc and equally unexpected superparamagnetic clusters associated with As vacancies. These observations lead us to conjecture that the tantalizing Tc enhancement may be associated with naturally occurring chemical interfaces and may thus provide a new paradigm in the search for superconductors with higher Tc.

  2. Vortex configurations in high-{Tc} superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Kaper, H.G.; Kwong, M.K.

    1992-11-23

    This article addresses the Ginzburg-Landau (GL) model for high-temperature superconductivity in thin films (two-dimensional periodic domains). A new gauge is defined to reduce the coupling between the equations for the nonzero components of the vector potential. The GL equations are written in a novel form by means of continuous link variables; this form is symmetric and has particular advantages for numerical analysis. The continuous GL model is approximated by a discrete model, which is shown to be second-order accurate. Two methods are used for the numerical solution of the discrete model - a modified Newton`s method, in combination with a sweeping algorithm for the solution of the linear system, and a time-like integration method based on gradient flow. Numerical experiments demonstrate that the discrete GL model leads to asymmetric solutions in the plane; symmetry is recovered only in the limit as the mesh size goes to zero. The results of computational experiments to find the upper critical field and establish an empirical power law for vortex interactions are given.

  3. Critical currents and superconductivity ferromagnetism coexistence in high-Tc oxides

    CERN Document Server

    Khene, Samir

    2016-01-01

    The book comprises six chapters which deal with the critical currents and the ferromagnetism-superconductivity coexistence in high-Tc oxides. It begins by gathering key data for superconducting state and the fundamental properties of the conventional superconductors, followed by a recap of the basic theories of superconductivity. It then discusses the differences introduced by the structural anisotropy on the Ginzburg-Landau approach and the Lawrence-Doniach model before addressing the dynamics of vortices and the ferromagnetism-superconductivity coexistence in high-Tc oxides, and provides an outline of the pinning phenomena of vortices in these materials, in particular the pinning of vortices by the spins. It elucidates the methods to improve the properties of superconducting materials for industrial applications. This optimization aims at obtaining critical temperatures and densities of critical currents at the maximum level possible. Whereas the primary objective is the basic mechanisms pushing the superco...

  4. Experimental study of the lower critical field in high-{Tc}-single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Brandstatter, C.; Boehmer, C. [Atominstitut der Oesterreichischen Univ., Wien (Austria); Weber, H.W.; Veal, B.W. [Argonne National Lab., IL (United States). Materials Science Div.

    1997-08-01

    Employing SQUID magnetometry and novel measuring and evaluation techniques, precise information on the first penetration field can be obtained and used to extract H{sub cl}. Tl- and Bi-based as well as a series of oxygen deficient Y-123 high {Tc} superconducting single crystals were investigated (H{parallel}c). In all cases, H{sub cl} is smaller than previously reported and can be described by BCS-theory.

  5. A new calculating formula of iodometric titration for high Tc superconductors

    Science.gov (United States)

    Chen, W. M.; Lam, C. C.; Geng, J. F.; Li, L. Y.; Hung, K. C.; Jin, X.

    1996-02-01

    In order to determine the effective oxidation state of Cu ( p) and oxygen content ( y) with the iodometric method, a new formula for calculating p and y of high Tc copper oxides is presented here. The formula of p involves a corrective term of 8 CV1/ M1, which reduces a systematic calculating error. With this approach, for YBCO, the value of p of YBCO is improved by 5% and y by 0.02, as compared with the conventional method.

  6. Modeling in Nonlinear Vibrations of a High-Tc Superconducting Levitation System

    OpenAIRE

    長屋, 幸助; 周東, 俊介

    1996-01-01

    Three dimensional analytical results for the levitation force of a vibrating high-Tc superconducting levitation system were presented. When the levitated superconductor vibrates, the levitation force shows nonlinear relationships with the air gap, amplitude and vibration frequency, so that the convensional models which do not consider dynamic effects cannot be applied. In the model proposed by(Uesaka et al.), dynamic effects are considered, but the critical current is constant. We propose an ...

  7. The Effect of Twins on Critical Currents of High Tc Superconductors

    Science.gov (United States)

    1989-01-01

    Currents of High Tc Superconductors " - A.M. Campbell and M.F. Ashby The initial work on levitation forces and separation of superconducting powders has...divided into two projects which are being pursued simultaneously. .The first is the nature of the frictional forces and damping oii levitated magnets...Although it is reasonable to suppose this arises from AC losses in the superconductor , magnets rotating about their centre of symmetry should not give

  8. Highly Compact Composite Antenna

    OpenAIRE

    Pigeon, Mélusine; Morlaas-Courties, Christophe; Aubert, Hervé; Souny, Bernard

    2009-01-01

    International audience; The highly compact antenna proposed in this communication consists of a judicious association of equivalent magnetic current source with equivalent electric current source. This composite antenna presents a directivity radiation pattern analogous to one of the microstrip ceramic antennas but can be used at low frequencies. The antenna measurements confirm the promising performances obtained from electromagnetic simulations.

  9. Hall effect in high- Tc Y 1Ba 2Cu 3O 7-δ superconductor

    Science.gov (United States)

    Vezzoli, G. C.; Burke, T.; Moon, B. M.; Lalevic, B.; Safari, A.; Sundar, H. G. K.; Bonometti, R.; Alexander, C.; Rau, C.; Waters, K.

    1989-04-01

    We have performed point-by-point and continuous Hall effect experiments as a function of temperature in polycrystalline Y 1Ba 2Cu 3O 7-δ. We have shown that the positive Hall constant shows an abrupt increase upon decreasing temperature at a value just above Tc. This temperature corresponds to where the resistance versus temperature data deviates from linearity. At very high fields of 6.8 and 15 T we observe a subsequent decrease in RH. We interpret these data as supportive of a contribution toward the superconductivity mechanism arising from internal excitions or change transfer excitations such that the bound exciton concentration increases near Tc at the expense of positive carries which are reflected in both bound and free holes.

  10. Extended abstracts of the 12th JAERI workshop on high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hojou, Kiichi; Okayasu, Satoru; Sasase, Masato [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishida, Takekazu [Osaka Prefectual Univ., Sakai (JP)] (eds.)

    2001-03-01

    This workshop was held on December 7-8, 2000 at JAERI (Tokai). The research group at JAERI shares a responsibility for material modification of high-Tc superconductors by irradiation in 'the multi-core project II of the high temperature superconducting material research' organized by STA (Science and Technology Agency) of Japan. This report contains the extended abstracts of workshop presentations covering basic theories, various experimental results and material improvement studies of the superconductivity by high energy ion irradiation. The twelve presentations of the workshop were devoted to a mini symposium where the direct observations of vortices were discussed in view of the various sophisticated techniques. (author)

  11. Singularity in the positive Hall coeffcient near pre-onset temperatures in high-Tc superconductors

    Science.gov (United States)

    Vezzoli, G. C.; Chen, M. F.; Craver, F.; Moon, B. M.; Safari, A.; Burke, T.; Stanley, W.

    1990-10-01

    Hall measurements using continuous extremely slow cooling and reheating rates as well as employing eqiulibrium point-by-point conventional techniques reveals a clear anomally in RH at pre-onset temperatures near Tc in polycrystalline samples Y1Ba2Cu3O7 and Bi2Sr2Ca2Cu3O10. The anomaly has the appearance of a singularity of Dirac-delta function which parallels earlier work on La1-xSrxCuO4. Recent single crystal work on the Bi-containing high-Tc superconductor is in accord with a clearcut anomaly. The singularity is tentatively interpreted to be associated (upon cooling) with initially the removal of positive holes from the hopping conduction system of the normal state such as from the increased concentration of bound virtual excitons due to increased exciton and hole lifetimes at low temperature. Subsequently the formation of Cooper pairs by mediation from these centers (bound-holes) and/or bound excitons) may cause an ionization of these bound virtual excitons thereby re-introducing holes and electrons into the conduction system at Tc.

  12. Random magnetic field and quasiparticle transport in the mixed state of high- Tc cuprates.

    Science.gov (United States)

    Ye, J

    2001-01-08

    By a singular gauge transformation, the quasiparticle transport in the mixed state of high- Tc cuprates is mapped into a charge-neutral Dirac moving in short-range correlated random scalar and long-range correlated vector potential. A fully quantum mechanical approach to longitudinal and transverse thermal conductivities is presented. The semiclassical Volovik effect is presented in a quantum mechanical way. The quasiparticle scattering from the random magnetic field which was completely missed in all the previous semiclassical approaches is the dominant scattering mechanism at sufficient high magnetic field. The implications for experiments are discussed.

  13. A novel phthalimide derivative, TC11, has preclinical effects on high-risk myeloma cells and osteoclasts.

    Directory of Open Access Journals (Sweden)

    Maiko Matsushita

    Full Text Available Despite the recent advances in the treatment of multiple myeloma (MM, MM patients with high-risk cytogenetic changes such as t(4;14 translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the Cmax was 2.1 μM at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by α-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1, whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing.

  14. Assessment of radionuclidic impurities in cyclotron produced (99m)Tc.

    Science.gov (United States)

    Lebeda, Ondřej; van Lier, Erik J; Štursa, Jan; Ráliš, Jan; Zyuzin, Alexander

    2012-11-01

    The commercial viability of cyclotron-produced (99m)Tc as an alternative to generator-produced (99m)Tc depends on several factors. These include: production yield, ease of target processing and recycling of (100)Mo, radiochemical purity, specific activity as well as the presence of other radionuclides, particularly various Tc radioisotopes that cannot be separated chemically and will remain in the final clinical preparation. These Tc radionuclidic impurities are derived from nuclear interactions of the accelerated protons with other stable Mo isotopes present in the enriched (100)Mo target. The aim of our study was to determine experimentally the yields of Tc radioisotopes produced from these stable Mo isotopes as a function of incident beam energy in order to predict radionuclidic purity of (99m)Tc produced in highly enriched (100)Mo targets of known isotopic composition. Enriched molybdenum targets of (95)Mo, (96)Mo, (97)Mo, (98)Mo and (100)Mo were prepared by pressing powdered metal into an aluminum target support. The thick targets were bombarded with 10 to 24MeV protons using the external beam line of the U-120M cyclotron of the Nuclear Physics Institute, Řež. The thick target yields of (94)Tc, (94m)Tc, (95)Tc, (95m)Tc, (96m+g)Tc and (97m)Tc were derived from their activities measured by γ spectrometry using a high purity Ge detector. These data were then used to assess the effect of isotopic composition of highly enriched (100)Mo targets on the radionuclidic purity of (99m)Tc as a function of proton beam energy. Estimates were validated by comparison to measured activities of Tc radioisotopes in proton irradiated, highly enriched (100)Mo targets of known isotopic composition. The measured thick target yields of (94)Tc, (94m)Tc, (95)Tc, (95m)Tc, (96m+g)Tc and (97m)Tc correspond well with recently published values calculated via the EMPIRE-3 code. However, the measured yields are more favourable with regard to achievable radionuclidic purity of (99m)Tc

  15. CD3+CD8+CD161high Tc17 cells are depleted in HIV-infection

    DEFF Research Database (Denmark)

    Gaardbo, Julie Christine; Hartling, Hans Jakob; Thorsteinsson, Kristina

    2012-01-01

    CD8+ Tc17 cells with pro-inflammatory properties have only recently been acknowledged, and Tc17 cells in HIV-infection are undescribed. CD3+CD8+CD161 Tc17 cells and the production of Interleukin-17 were examined in untreated and treated HIV-infected patients, HIV-HCV co-infected patients...... and healthy controls. Depletion of CD3+CD8+CD161 Tc17 cells and diminished production of Interleukin-17 in HIV-infected patients was found. The level of Tc17 cells was associated with the level of the CD4+ count in treated patients....

  16. The NMR probe of high-Tc materials and correlated electron systems

    CERN Document Server

    Walstedt, Russell E

    2018-01-01

    This new edition updates readers in three areas of NMR studies, namely, recent developments in high-Tc materials, heavy fermion systems and actinide oxides are presented.  The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-Tc materials, especially the advances in the area of pseudogap studies are reviewed.  An in depth overview of heavy fermion systems is presented in the second part,  notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth o...

  17. Internal resonance of an elastic body levitated above high-Tc superconducting bulks

    Science.gov (United States)

    Kokuzawa, T.; Toshihiko, S.; Yoshizawa, M.

    2010-06-01

    In high-Tc superconducting magnetic levitation systems, levitated bodies can keep stable levitation with no contact and no control and thus their damping is very small. Thanks to these features, their applications to various apparatus are expected. However, on account of their small damping, the nonlinearity of electromagnetic levitation force can give notable effects upon motion of the levitated bodies. Therefore this nonlinearity must be taken into account to accurately analyze the dynamical behavior of the levitated bodies. Structures of such a levitated body can show elastic deformation if the large electromagnetic force acts on it. Therefore, we need to deal with the model as an elastic body. As mentioned above, nonlinear characteristics easily appear in this elastic vibration on account of the small damping. Especially when the ratio of the natural frequencies of the eigenmodes is integer, internal resonance can occur. This nonlinear resonance is derived from nonlinear interactions among the eigenmodes of the elastic levitated body. This kind of internal resonance of an elastic body appearing in high-Tc superconducting levitation systems has not been studied so far. This research especially deals with internal resonance of a beam supported at both its ends by electromagnetic forces acting on permanent magnets. The governing equation with the nonlinear boundary conditions for the dynamics of a levitated beam has been derived. Numerical results show internal resonance of the 1st mode and the 3rd mode. Experimental results are qualitatively in good agreement with numerical ones.

  18. Levitation performance of the magnetized bulk high- Tc superconducting magnet with different trapped fields

    Science.gov (United States)

    Liu, W.; Wang, J. S.; Liao, X. L.; Zheng, S. J.; Ma, G. T.; Zheng, J.; Wang, S. Y.

    2011-03-01

    To a high- Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high- Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  19. Vibration reduction using autoparametric resonance in a high-Tc superconducting levitation system

    Science.gov (United States)

    Yamasaki, Hiroshi; Takazakura, Toyoki; Sakaguchi, Ryunosuke; Sugiura, Toshihiko

    2014-05-01

    High-Tc superconducting levitation systems have very small damping and enable stable levitation without control. Therefore, they can be applied to various kinds of application. However, there are some problems that small damping produces large vibration and nonlinearity of magnetic force can generate complicated phenomena. Accordingly, analysis of these phenomena and reduction of vibration occurring in the system are important. In this study, we examined reduction of vibration without using any absorbers, but utilizing autoparametric resonance caused by nonlinear coupling between vertical oscillation and horizontal oscillation. We conducted numerical analysis and experiments in order to investigate motions of a rigid bar levitated by the electromagnetic force from high-Tc superconductors. As a result, if the ratio of the natural frequency of vertical oscillation and that of horizontal oscillation is two to one, the vertical oscillation decreases while the horizontal oscillation is excited. Thus, it was confirmed that the amplitude of a primary resonance can be reduced by occurrence of autoparametric resonance without using any absorbers.

  20. Josephson junction between two high Tc superconductors with arbitrary transparency of interface

    Directory of Open Access Journals (Sweden)

    GhR Rashedi

    2010-03-01

    Full Text Available In this paper, a dc Josephson junction between two singlet superconductors (d-wave and s-wave with arbitrary reflection coefficient has been investigated theoretically. For the case of high Tc superconductors, the c-axes are parallel to an interface with finite transparency and their ab-planes have a mis-orientation. The physics of potential barrier will be demonstrated by a transparency coefficient via which the tunneling will occur. We have solved the nonlocal Eilenberger equations and obtained the corresponding and suitable Green functions analytically. Then, using the obtained Green functions, the current-phase diagrams have been calculated. The effect of the potential barrier and mis-orientation on the currents is studied analytically and numerically. It is observed that, the current phase relations are totally different from the case of ideal transparent Josephson junctions between d-wave superconductors and two s-wave superconductors. This apparatus can be used to demonstrate d-wave order parameter in high Tc superconductors.

  1. Development and characterization of highly polymorphic long TC repeat microsatellite markers for genetic analysis of peanut

    Directory of Open Access Journals (Sweden)

    Macedo Selma E

    2012-02-01

    Full Text Available Abstract Background Peanut (Arachis hypogaea L. is a crop of economic and social importance, mainly in tropical areas, and developing countries. Its molecular breeding has been hindered by a shortage of polymorphic genetic markers due to a very narrow genetic base. Microsatellites (SSRs are markers of choice in peanut because they are co-dominant, highly transferrable between species and easily applicable in the allotetraploid genome. In spite of substantial effort over the last few years by a number of research groups, the number of SSRs that are polymorphic for A. hypogaea is still limiting for routine application, creating the demand for the discovery of more markers polymorphic within cultivated germplasm. Findings A plasmid genomic library enriched for TC/AG repeats was constructed and 1401 clones sequenced. From the sequences obtained 146 primer pairs flanking mostly TC microsatellites were developed. The average number of repeat motifs amplified was 23. These 146 markers were characterized on 22 genotypes of cultivated peanut. In total 78 of the markers were polymorphic within cultivated germplasm. Most of those 78 markers were highly informative with an average of 5.4 alleles per locus being amplified. Average gene diversity index (GD was 0.6, and 66 markers showed a GD of more than 0.5. Genetic relationship analysis was performed and corroborated the current taxonomical classification of A. hypogaea subspecies and varieties. Conclusions The microsatellite markers described here are a useful resource for genetics and genomics in Arachis. In particular, the 66 markers that are highly polymorphic in cultivated peanut are a significant step towards routine genetic mapping and marker-assisted selection for the crop.

  2. 99mTc-labeled HYNIC-DAPI causes plasmid DNA damage with high efficiency.

    Directory of Open Access Journals (Sweden)

    Joerg Kotzerke

    Full Text Available (99mTc is the standard radionuclide used for nuclear medicine imaging. In addition to gamma irradiation, (99mTc emits low-energy Auger and conversion electrons that deposit their energy within nanometers of the decay site. To study the potential for DNA damage, direct DNA binding is required. Plasmid DNA enables the investigation of the unprotected interactions between molecules and DNA that result in single-strand breaks (SSBs or double-strand breaks (DSBs; the resulting DNA fragments can be separated by gel electrophoresis and quantified by fluorescent staining. This study aimed to compare the plasmid DNA damage potential of a (99mTc-labeled HYNIC-DAPI compound with that of (99mTc pertechnetate ((99mTcO4(-. pUC19 plasmid DNA was irradiated for 2 or 24 hours. Direct and radical-induced DNA damage were evaluated in the presence or absence of the radical scavenger DMSO. For both compounds, an increase in applied activity enhanced plasmid DNA damage, which was evidenced by an increase in the open circular and linear DNA fractions and a reduction in the supercoiled DNA fraction. The number of SSBs elicited by 99mTc-HYNIC-DAPI (1.03 was twice that caused by (99mTcO4(- (0.51, and the number of DSBs increased fivefold in the (99mTc-HYNIC-DAPI-treated sample compared with the (99mTcO4(- treated sample (0.02 to 0.10. In the presence of DMSO, the numbers of SSBs and DSBs decreased to 0.03 and 0.00, respectively, in the (99mTcO4(- treated samples, whereas the numbers of SSBs and DSBs were slightly reduced to 0.95 and 0.06, respectively, in the (99mTc-HYNIC-DAPI-treated samples. These results indicated that (99mTc-HYNIC-DAPI induced SSBs and DSBs via a direct interaction of the (99mTc-labeled compound with DNA. In contrast to these results, (99mTcO4(- induced SSBs via radical formation, and DSBs were formed by two nearby SSBs. The biological effectiveness of (99mTc-HYNIC-DAPI increased by approximately 4-fold in terms of inducing SSBs and by approximately

  3. Performance of a high Tc superconducting ultralow-loss microwave stripline filter

    Science.gov (United States)

    Zahopoulos, C.; Sridhar, S.; Bautista, J. J.; Ortiz, G.; Lanagan, M.

    1991-01-01

    The successful fabrication is reported of a five-pole interdigital stripline filter made of the 93 K superconductor Y1Ba2Cu3O(y) coated on a silver substrate, with a center frequency of 8.5 GHz and an extremely high rejection ratio of 80 dB. The lowest insertion loss measured was 0.1 dB at 12 K, with a return loss better than 16 dB, representing significant improvements over a similar Cu filter, and comparable to low Tc filters. The insertion loss appears to be limited by extrinsic factors such as tuning mismatch and joint losses, and not by the superconducting material losses.

  4. Nonlinear resonances of three modes in a high-Tc superconducting magnetic levitation system

    Science.gov (United States)

    Sasaki, Masahiko; Sakaguchi, Ryunosuke; Sugiura, Toshihiko

    2013-11-01

    In a high-Tc superconducting magnetic levitation system, an object can levitate without control and contact. So it is expected to be applied to magnetically levitated transportation. To use it safely, lightening the levitated object is necessary. But this reduces the bending stiffness of the object. Besides, the system has nonlinearity. Therefore nonlinear elastic vibration can occur. This study focused on how plural nonlinear elastic vibrations of the 1st, 2nd and 3rd modes simultaneously occur. Our numerical calculation and experiment found out that the three modes simultaneously resonate when the amplitude of the 2nd mode is large enough whereas only the 2nd mode resonates when it is small.

  5. Advanced nanoscopic studies in magneto-electric manganites and high T$_c$ superconductors

    CERN Document Server

    Melo Mendonça, Tânia Manuela; Martins Correia, João Guilherme

    2012-05-01

    Technological advances in materials synthesis and the development of new experimental techniques have created a wealth of information with remarkable implications for understanding the macroscopic properties of systems with strongly correlated electronic properties. These advances allowed the observation of a wide range of exotic phenomena such as high T$_c$ superconductivity, colossal magneto-resistance or, more recently, multiferroic behavior, which are known to be strongly dependent on the nanoscale phenomenology. In fact, several experimental and theoretical studies demonstrated that strongly correlated electron systems are not homogeneous at a local scale due to simultaneously active spin, charge, lattice and/or orbital interactions. Consequently, these systems show nanoscale chemical and electronic disorder, which lead to a rich variety of macroscopic properties. It is under this scope that the nuclear hyperfine techniques are introduced, being particularly useful to infer the local lattice structure, e...

  6. 3D modeling of high-Tc superconductors by finite element software

    Science.gov (United States)

    Zhang, Min; Coombs, T. A.

    2012-01-01

    A three-dimensional (3D) numerical model is proposed to solve the electromagnetic problems involving transport current and background field of a high-Tc superconducting (HTS) system. The model is characterized by the E-J power law and H-formulation, and is successfully implemented using finite element software. We first discuss the model in detail, including the mesh methods, boundary conditions and computing time. To validate the 3D model, we calculate the ac loss and trapped field solution for a bulk material and compare the results with the previously verified 2D solutions and an analytical solution. We then apply our model to test some typical problems such as superconducting bulk array and twisted conductors, which cannot be tackled by the 2D models. The new 3D model could be a powerful tool for researchers and engineers to investigate problems with a greater level of complicity.

  7. Real-space fluctuations of effective exchange integrals in high-Tc cuprates

    Science.gov (United States)

    Petit, S.; Lepetit, M.-B.

    2009-09-01

    We present ab initio calculations of effective magnetic exchange, J, as well as Hubbard parameters (t, U and δɛ) as a function of the local distribution of doping atoms for the high-Tc superconducting (CaxLa1-x)(Ba1.75-xLa0.25+x)Cu3Oy family. We found that both the exchange and the energies of the magnetic orbitals are strongly dependent on the local dopant distribution, both through the induced modification of the apical oxygen location and of the induced local electrostatic potential. The J real-space map, for a random distribution of dopants, positively compares with observed STS gap inhomogeneity maps. Similarly, the orbital energy fluctuations induce weak charge inhomogeneities on copper sites, that can be positively compared with the observed LDOS inhomogeneities. These results clearly support an extrinsic origin of both the gap inhomogeneities and LDOS.

  8. Efficient CAD Model to Analysis of High Tc Superconducting Circular Microstrip Antenna on Anisotropic Substrates

    Directory of Open Access Journals (Sweden)

    S. Bedra

    2017-05-01

    Full Text Available In this paper, an electromagnetic approach based on cavity model in conjunction with electromagnetic knowledge was developed. The cavity model combined with London’s equations and the Gorter-Casimir two-fluid model has been improved to investigate the resonant characteristics of high Tc superconducting circular microstrip patch in the case where the patch is printed on uniaxially anisotropic substrate materials.  Merits of our extended model include low computational cost and mathematical simplify. The numerical simulation of this modeling shows excellent agreement with experimental results available in the literature. Finally, numerical results for the dielectric anisotropic substrates effects on the operating frequencies for the case of superconducting circular patch are also presented.

  9. A novel phenylphthalimide derivative, pegylated TC11, improves pharmacokinetic properties and induces apoptosis of high-risk myeloma cells via G2/M cell-cycle arrest.

    Science.gov (United States)

    Aida, Shuji; Hozumi, Masashi; Ichikawa, Daiju; Iida, Kazuki; Yonemura, Yuko; Tabata, Noriko; Yamada, Taketo; Matsushita, Maiko; Sugai, Takeshi; Yanagawa, Hiroshi; Hattori, Yutaka

    2017-11-04

    Despite the development of new drugs for multiple myeloma (MM), the prognosis of MM patients with high-risk cytogenetic abnormalities such as t (4; 14) and del17p remains poor. We reported that a novel phenylphthalimide derivative, TC11, induced apoptosis of MM cells in vitro and in vivo, and TC11 directly bound to α-tubulin and nucleophosmin-1 (NPM1). However, TC11 showed low water solubility and poor pharmacokinetic properties. Here we synthesized a water-soluble TC11-derivative, PEG(E)-TC11, in which HOEtO-TC11 is pegylated with PEG through an ester bond, and we examined its anti-myeloma activity. We observed that PEG(E)-TC11 and its hydrolyzed product, HOEtO-TC11, induced G2/M arrest and the apoptosis of MM cells. Intraperitoneal administration of PEG(E)-TC11 to xenografted mice revealed improved pharmacokinetic properties and significantly delayed tumor growth. TC11 and its derivatives did not bind to cereblon (CRBN), which is a responsible molecule for thalidomide-induced teratogenicity. These results suggest that PEG(E)-TC11 is a good candidate drug for treating high-risk MM. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Influence of high pulsed magnetic field on tensile properties of TC4 alloy

    Science.gov (United States)

    Li, Gui-Rong; Wang, Fang-Fang; Wang, Hong-Ming; Zheng, Rui; Xue, Fei; Cheng, Jiang-Feng

    2017-04-01

    The tensile tests of TC4 alloy are carried on electronic universal testing machine in the synchronous presence of high pulsed magnetic field (HPMF) parallel to the axial direction. The effects of magnetic induction intensity (B=0, 1 T, 3 T, and 5 T) on elongation (δ) of TC4 alloy are investigated. At 3 T, the elongation arrives at a maximum value of 12.41%, which is enhanced by 23.98% in comparison with that of initial sample. The elongation curve shows that 3 T is a critical point. With B increasing, the volume fraction of α phase is enhanced from 49.7% to 55.9%, which demonstrates that the HPMF can induce the phase transformation from β phase to α phase. Furthermore, the magnetic field not only promotes the orientation preference of crystal plane along the slipping direction, but also has the effect on increasing the dislocation density. The dislocation density increases with the enhancement of magnetic induction intensity and the 3-T parameter is ascertained as a turning point from increase to decrease tendency. When B is larger than 3 T, the dislocation density decreases with the enhancement of B. The influence of magnetic field is analyzed on the basis of magneto-plasticity effect. The high magnetic field will enhance the dislocation strain energy and promote the state conversion of radical pair generated between the dislocation and obstacles from singlet into triplet state, in which is analyzed the phenomenon that the dislocation density is at an utmost with B=3 T. Finally, the inevitability of optimized 3-T parameter is further discussed on a quantum scale. Project supported by the National Natural Science Foundation of China (Grant Nos. 51371091, 51174099, and 51001054) and the Industrial Center of Jiangsu University, China (Grant No. ZXJG201585).

  11. Vertical Cloud Climatology During TC4 Derived from High-Altitude Aircraft Merged Lidar and Radar Profiles

    Science.gov (United States)

    Hlavka, Dennis; Tian, Lin; Hart, William; Li, Lihua; McGill, Matthew; Heymsfield, Gerald

    2009-01-01

    Aircraft lidar works by shooting laser pulses toward the earth and recording the return time and intensity of any of the light returning to the aircraft after scattering off atmospheric particles and/or the Earth s surface. The scattered light signatures can be analyzed to tell the exact location of cloud and aerosol layers and, with the aid of a few optical assumptions, can be analyzed to retrieve estimates of optical properties such as atmospheric transparency. Radar works in a similar fashion except it sends pulses toward earth at a much larger wavelength than lidar. Radar records the return time and intensity of cloud or rain reflection returning to the aircraft. Lidar can measure scatter from optically thin cirrus and aerosol layers whose particles are too small for the radar to detect. Radar can provide reflection profiles through thick cloud layers of larger particles that lidar cannot penetrate. Only after merging the two instrument products can accurate measurements of the locations of all layers in the full atmospheric column be achieved. Accurate knowledge of the vertical distribution of clouds is important information for understanding the Earth/atmosphere radiative balance and for improving weather/climate forecast models. This paper describes one such merged data set developed from the Tropical Composition, Cloud and Climate Coupling (TC4) experiment based in Costa Rica in July-August 2007 using the nadir viewing Cloud Physics Lidar (CPL) and the Cloud Radar System (CRS) on board the NASA ER-2 aircraft. Statistics were developed concerning cloud probability through the atmospheric column and frequency of the number of cloud layers. These statistics were calculated for the full study area, four sub-regions, and over land compared to over ocean across all available flights. The results are valid for the TC4 experiment only, as preferred cloud patterns took priority during mission planning. The TC4 Study Area was a very cloudy region, with cloudy

  12. Effects of Hot-Hydrostatic Canned Extrusion on the Stock Utilization, Microstructure and Mechanical Properties of TiBw/TC4 Composites with Quasi-Continuous Network.

    Science.gov (United States)

    Feng, Yangju; Li, Bing; Cui, Guorong; Zhang, Wencong

    2017-10-25

    In-situ TiB whisker-reinforced Ti-6Al-4V (TC4) titanium matrix composites (TiBw/TC4) with quasi-continuous networks were successfully fabricated by vacuum hot-pressing sintering. The effects of the hot-hydrostatic canned extrusion on stock utilization, microstructure and mechanical properties of the TiBw/TC4 composites were investigated. It was satisfactory that the utilization of composites could be obviously improved by canned extrusion compared to that extruded without canned extrusion. The microstructure results showed that after canned extrusion the grain was refined and the TiB whiskers were distributed from a random array state to a state in which the whiskers were distributed along the extrusion direction. The properties testing results revealed that the tensile strength, the hardness and the ductility of the composites all significantly improved after extrusion due to the grain refinement and orientation of the TiB whisker caused by extrusion. Tensile fracture results showed that when the TiB whiskers were randomly distributed only part of them played a role in strengthening the matrix during the deformation process (as-sintered composites), while when the TiB whiskers were oriented all whiskers could strengthen the matrix during the tensile testing process (as-extruded composites).

  13. Unconventional charge order in a co-doped high-Tc superconductor

    Science.gov (United States)

    Pelc, D.; Vučković, M.; Grafe, H.-J.; Baek, S.-H.; Požek, M.

    2016-09-01

    Charge-stripe order has recently been established as an important aspect of cuprate high-Tc superconductors. However, owing to the complex interplay between competing phases and the influence of disorder, it is unclear how it emerges from the parent high-temperature state. Here we report on the discovery of an unconventional ordered phase between charge-stripe order and (pseudogapped) metal in the cuprate La1.8-xEu0.2SrxCuO4. We use three complementary experiments--nuclear quadrupole resonance, nonlinear conductivity and specific heat--to demonstrate that the order appears through a sharp phase transition and exists in a dome-shaped region of the phase diagram. Our results imply that the new phase is a state, which preserves translational symmetry: a charge nematic. We thus resolve the process of charge-stripe development in cuprates, show that this nematic phase is distinct from high-temperature pseudogap and establish a link with other strongly correlated electronic materials with prominent nematic order.

  14. Unconventional charge order in a co-doped high-Tc superconductor.

    Science.gov (United States)

    Pelc, D; Vučković, M; Grafe, H-J; Baek, S-H; Požek, M

    2016-09-08

    Charge-stripe order has recently been established as an important aspect of cuprate high-Tc superconductors. However, owing to the complex interplay between competing phases and the influence of disorder, it is unclear how it emerges from the parent high-temperature state. Here we report on the discovery of an unconventional ordered phase between charge-stripe order and (pseudogapped) metal in the cuprate La1.8-xEu0.2SrxCuO4. We use three complementary experiments-nuclear quadrupole resonance, nonlinear conductivity and specific heat-to demonstrate that the order appears through a sharp phase transition and exists in a dome-shaped region of the phase diagram. Our results imply that the new phase is a state, which preserves translational symmetry: a charge nematic. We thus resolve the process of charge-stripe development in cuprates, show that this nematic phase is distinct from high-temperature pseudogap and establish a link with other strongly correlated electronic materials with prominent nematic order.

  15. Compositional equivalency of Cry1F corn event TC6275 and conventional corn (Zea mays L.).

    Science.gov (United States)

    Herman, Rod A; Phillips, Amy M; Collins, Randy A; Tagliani, Laura A; Claussen, Fred A; Graham, Christopher D; Bickers, Brenda L; Harris, Travis A; Prochaska, Lee M

    2004-05-05

    Maize (Zea mays L.) plants have been transformed to express a Cry1F insecticidal crystal protein originally isolated from Bacillus thuringiensis Berliner. This protein controls lepidopteran pests of maize, including the European corn borer, Ostrinia nubilalis (Hübner). As part of the safety assessment for crops containing transgenes, a compositional analysis of the food and feed is conducted. This analysis is designed to detect unintended changes in the nutrient and antinutrient content of the raw commodities produced by the crop due to the insertion of the genes into the genomic DNA of the plant (pleotropic effects). Samples of transgenic and nontransgenic maize forage and grain were collected from six field sites located in the U.S. and Canada. Forage samples were analyzed for proximates and minerals, and grain was further analyzed for fatty acids, amino acids, vitamins, secondary metabolites, and antinutrients. Results demonstrated that maize expressing the Cry1F protein was equivalent to nontransgenic maize with respect to these important components. Comparison of the variability within the nontransgenic and transgenic hybrid, as compared to composition values reported in the literature, suggest that factors other than transgenes may contribute more substantially to the composition of crops.

  16. High resolution spectroscopy of the hyperfine structure splitting in 97,99Tc

    Science.gov (United States)

    Raeder, Sebastian; Kron, Tobias; Heinke, Reinhard; Henares, Jose L.; Lecesne, Nathalie; Schönberg, Pascal; Trümper, Marcel; Wendt, Klaus

    2017-11-01

    Resonance ionization mass spectrometry is an efficient tool for detecting trace amounts of long-lived radio-isotopes in environmental samples. For absolute quantification a tracer with identical atomic properties and chemical behavior is needed to prevent a possible dependency onto the absolute efficiency for the analytical method. For an application in 99Tc, the isotope 97Tc could serve as a potential tracer. Therefore the optical transitions of an efficient ionization scheme for technetium were investigated for the two odd mass isotopes 97,99Tc, both with a nuclear spin of I={9}/{2}. Using a pulsed, single mode laser with narrow bandwidth, the hyperfine structures (HFS) of two transitions were fully resolved. The observed isotope shift is small in comparison to the width of the hyperfine structure splitting. This is ideal for the application of 97Tc as tracer isotope for 99Tc quantification. The evaluation of the observed HFS splitting results in a first experimental value for the magnetic dipole for 97Tc of μ=+5.82(9) μ N .

  17. Prediction of high-Tc conventional superconductivity in the ternary lithium borohydride system

    Science.gov (United States)

    Kokail, Christian; von der Linden, Wolfgang; Boeri, Lilia

    2017-12-01

    We investigate the superconducting ternary lithium borohydride phase diagram at pressures of 0 and 200 GPa using methods for evolutionary crystal structure prediction and linear-response calculations for the electron-phonon coupling. Our calculations show that the ground state phase at ambient pressure, LiBH4, stays in the P n m a space group and remains a wide band-gap insulator at all pressures investigated. Other phases along the 1 :1 :x Li:B:H line are also insulating. However, a full search of the ternary phase diagram at 200 GPa revealed a metallic Li2BH6 phase, which is thermodynamically stable down to 100 GPa. This superhydride phase, crystallizing in a F m 3 ¯m space group, is characterized by sixfold hydrogen-coordinated boron atoms occupying the fcc sites of the unit cell. Due to strong hydrogen-boron bonding this phase displays a critical temperature of ˜100 K between 100 and 200 GPa. Our investigations confirm that ternary compounds used in hydrogen-storage applications should exhibit high-Tc conventional superconductivity in diamond anvil cell experiments, and suggest a viable route to optimize the superconducting behavior of high-pressure hydrides, exploiting metallic covalent bonds.

  18. Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high efficiency SPECT

    Science.gov (United States)

    Brodov, Yafim; Fish, Mathews; Rubeaux, Mathieu; Otaki, Yuka; Gransar, Heidi; Lemley, Mark; Gerlach, Jim; Berman, Daniel; Germano, Guido; Slomka, Piotr

    2016-01-01

    Background Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. Methods Fifty patients (mean age 69 y) undergoing regadenoson same-day rest (8–11 mCi)/stress (32–42mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started one min after sequential intravenous regadenoson 0.4mg and Tc-99m injection, and was composed of five 2 min supine gated acquisitions followed by two 4 min supine and upright images. Ischemic total perfusion deficit (ITPD) ≥ 5 % was considered as significant ischemia. Results Significantly lower mean EF reserve was obtained in the 5th and 9th min after regadenoson bolus in patients with significant ischemia versus patients without (5th min: −4.2 ± 4.6% vs. 1.3 ± 6.6%, p = 0.006; 9th min: −2.7 ± 4.8% vs. 2.0 ± 6.6%, p = 0.03). Conclusions Negative EF reserve obtained between 5th and 9th min of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of myocardial stunning with Tc-99m HE-SPECT. PMID:27387521

  19. Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high-efficiency SPECT.

    Science.gov (United States)

    Brodov, Yafim; Fish, Mathews; Rubeaux, Mathieu; Otaki, Yuka; Gransar, Heidi; Lemley, Mark; Gerlach, Jim; Berman, Daniel; Germano, Guido; Slomka, Piotr

    2016-12-01

    Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. Fifty patients (mean age 69 years) undergoing regadenoson same-day rest (8-11 mCi)/stress (32-42 mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started 1 minute after sequential intravenous regadenoson .4 mg and Tc-99m injections, and was composed of five 2 minutes supine gated acquisitions followed by two 4 minutes supine and upright images. Ischemic total perfusion deficit (ITPD) ≥5 % was considered as significant ischemia. Significantly lower mean EF reserve was obtained in the 5th and 9th minute after regadenoson bolus in patients with significant ischemia vs patients without (5th minute: -4.2 ± 4.6% vs 1.3 ± 6.6%, P = .006; 9th minute: -2.7 ± 4.8% vs 2.0 ± 6.6%, P = .03). Negative EF reserve obtained between 5th and 9th minutes of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of transient ischemic functional changes with Tc-99m HE-SPECT.

  20. High-Tc dc-SQUID gradiometers in flip-chip configuration

    Science.gov (United States)

    Peiselt, K.; Schmidl, F.; Linzen, S.; Anton, A. S.; Hübner, U.; Seidel, P.

    2003-12-01

    We describe a new design of a gradiometric flip-chip antenna, which is inductively coupled to a dc-SQUID gradiometer. Both components are patterned out of thin films of the high-Tc superconductor YBa2Cu3O7-x (YBCO). For the flip-chip antenna, a 40 mm × 10 mm SrTiO3 single crystalline substrate is used, while the gradiometer sensors are prepared on 10 mm × 10 mm SrTiO3 bicrystal substrates. Special attention is paid to the inductive coupling between the flip-chip antenna and the read-out gradiometer antenna. We investigate different designs of coupling loops in order to optimize the coupling inductance between both components of the sensor. With optimized coupling the sensor achieves a field-gradient resolution of 12 fT cm-1 Hz-1/2 in the white noise region and of 310 fT cm-1 Hz-1/2 at 1 Hz in the unshielded laboratory environment.

  1. Report on neutron beam utilization and study of high Tc superconductors at NRI

    Energy Technology Data Exchange (ETDEWEB)

    Vuong Huu Tan [Nuclear Physics Dept., Nuclear Research Inst. (NRI), Dalat (Viet Nam)

    1998-10-01

    Utilization of reactor neutron beams at NRI for research and applications up to November 1996 had been presented at the last Workshop in Jakarta (25-28 Nov., 1996). This paper describes new research and applications carried out at Nuclear Physics Department of NRI after that time. They consist of neutron beam developments, neutron activation cross section measurements for waste disposal assessment and in-vivo prompt gamma neutron activation analysis for Cd determination in organs. After the last Sub-Workshop on Neutron Scattering in Serpong (21-23 Nov., 1996), we were accepted to participate in the Regional Program on Study of High Tc Superconductors with the topic `The mechanism of Pb and Sb dopant role on superconductivity of 2223 phase of Bi-Sr-Ca-Cu-O system`. Indeed, this study has begun at NRI only since August, 1997 due to the problem of materials. The study has been carried out in collaboration with the Hanoi State University (Superconductors Department) where experts and equipment for superconductors research have been considered as the best ones in Vietnam. Primary results in this study are presented in this workshop. (author)

  2. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  3. The Gap and the Upper Critical Field Hc2 as Function of Doping for High-Tc Cuprates

    Directory of Open Access Journals (Sweden)

    S. Orozco

    2014-01-01

    Full Text Available The relation between the d-wave superconducting gap Δ0 and the specific heat obtained with the Volovik effect is used to determine the upper critical field Hc2 as doping function, for high-temperature superconductors. A two-components model with d-wave symmetry, within the BCS framework, is introduced to describe the superconducting state. Generalized Fermi surface topologies are used in order to increase the density of states at the Fermi level, allowing the high-Tc values observed. The electron-phonon interaction is considered the most relevant mechanism for the high-Tc cuprates, where the available phonon energy is provided by the half-breathing modes. The energy gap values Δ0 calculated with this model are introduced to describe the variation of the upper critical field Hc2 as function of doping, for La2-xSrxCuO4.

  4. TC4 COSTA RICA LIGHTNING V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Tropical Composition, Cloud and Climate Coupling (TC4) mission TC4 field experiment was completed during July and August 2007 based out of San Jose, Costa Rica....

  5. Presentation of test cases TC-2A, TC-2B, TC-2C, TC-2D - Twodimensional, incompressible, wall flows with separation

    DEFF Research Database (Denmark)

    Scheel Larsen, Poul

    1988-01-01

    The four test cases comprise the backfacing step at high Re-number (TC-2A) and low Re-number (TC-2B), a low Re-number boundary layer flow past a thin obstacle, fence-on-wall (TC-2C), and a high Re-number developed channel flow past a squareobstacle (TC-2D). Geometry, test conditions and available...

  6. Enhancing magnetic ordering in Cr-doped Bi2Se3 using high-TC ferrimagnetic insulator.

    Science.gov (United States)

    Liu, Wenqing; He, Liang; Xu, Yongbing; Murata, Koichi; Onbasli, Mehmet C; Lang, Murong; Maltby, Nick J; Li, Shunpu; Wang, Xuefeng; Ross, Caroline A; Bencok, Peter; van der Laan, Gerrit; Zhang, Rong; Wang, Kang L

    2015-01-14

    We report a study of enhancing the magnetic ordering in a model magnetically doped topological insulator (TI), Bi(2-x)Cr(x)Se(3), via the proximity effect using a high-TC ferrimagnetic insulator Y(3)Fe(5)O(12). The FMI provides the TI with a source of exchange interaction yet without removing the nontrivial surface state. By performing the elemental specific X-ray magnetic circular dichroism (XMCD) measurements, we have unequivocally observed an enhanced TC of 50 K in this magnetically doped TI/FMI heterostructure. We have also found a larger (6.6 nm at 30 K) but faster decreasing (by 80% from 30 to 50 K) penetration depth compared to that of diluted ferromagnetic semiconductors (DMSs), which could indicate a novel mechanism for the interaction between FMIs and the nontrivial TIs surface.

  7. Improvement of High-Resolution Tropical Cyclone Structure and Intensity Forecasts using COAMPS-TC

    Science.gov (United States)

    2012-09-30

    north and east of the center. This large shield of heavy precipitation caused severe river flooding as it slowly moved north through the mid...invited) Doyle, J.D., 2011: An Overview of NRL’s COAMPS System and Physics. EMC Physics Workshop. 26-27 July 2011, NCEP/ EMC . Doyle, J.D., C...Overview of the COAMPS-TC Tropical Cyclone Boundary Layer Parameterization. HFIP Physics Workshop. 9-11 August 2011, NCEP/ EMC . 8 Hendricks, E

  8. An effective attractive electron-electron interaction and high-Tc superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Howson, M.A.; Porter, J.; Morgan, G.J. (Dept. of Physics, Univ. of Leeds (UK))

    1991-01-15

    The repulsive Coulomb interaction is usually seen as opposing the attractive phonon mediated interaction giving rise to superconductivity. Here we show how the vertex part for electron-electron scattering can lead to an effective attractive Coulomb interaction. We then solve the Eliashberg equations with this effective vertex correction and calculate Tc for a model density of states as we vary the strength of the interaction and the effective mass of the electrons. (orig.).

  9. Transiently enhanced interlayer tunneling in optically driven high-Tc superconductors

    Science.gov (United States)

    Okamoto, Jun-ichi; Hu, Wanzheng; Cavalleri, Andrea; Mathey, Ludwig

    2017-10-01

    Recent pump-probe experiments reported an enhancement of superconducting transport along the c axis of underdoped YBa2Cu3O6 +δ (YBCO), induced by a midinfrared optical pump pulse tuned to a specific lattice vibration. To understand this transient nonequilibrium state, we develop a pump-probe formalism for a stack of Josephson junctions, and we consider the tunneling strengths in the presence of modulation with an ultrashort optical pulse. We demonstrate that a transient enhancement of the Josephson coupling can be obtained for pulsed excitation and that this can be even larger than in a continuously driven steady state. Especially interesting is the conclusion that the effect is largest when the material is parametrically driven at a frequency immediately above the plasma frequency, in agreement with what is found experimentally. For bilayer Josephson junctions, an enhancement similar to that experimentally is predicted below the critical temperature Tc. This model reproduces the essential features of the enhancement measured below Tc. To reproduce the experimental results above Tc, we will explore extensions of this model, such as in-plane and amplitude fluctuations, elsewhere.

  10. High specific heat superconducting composite

    Science.gov (United States)

    Steyert, Jr., William A.

    1979-01-01

    A composite superconductor formed from a high specific heat ceramic such as gadolinium oxide or gadolinium-aluminum oxide and a conventional metal conductor such as copper or aluminum which are insolubly mixed together to provide adiabatic stability in a superconducting mode of operation. The addition of a few percent of insoluble gadolinium-aluminum oxide powder or gadolinium oxide powder to copper, increases the measured specific heat of the composite by one to two orders of magnitude below the 5.degree. K. level while maintaining the high thermal and electrical conductivity of the conventional metal conductor.

  11. The Effect of (99m)Tc on Dual-Energy X-Ray Absorptiometry Measurement of Body Composition and Bone Mineral Density

    DEFF Research Database (Denmark)

    Fosbøl, Marie Øbro; Dupont, Anders; Alslev, Louise

    2012-01-01

    Whether the γ-emission by radioisotopes influences the outcome of dual-energy X-ray absorptiometry (DXA) measurements is not fully elucidated. The aim of this study was to evaluate the effect of antecedent administration of (99m)Tc on DXA measurements regarding body composition and bone mineral...... density (BMD) using a K-edge filter scanner. The phantom measurements were performed by placing a urinary bladder phantom containing 40mL of radioisotope solution on the pelvic region of a whole-body phantom. Twenty-seven patients attending our department for a routine examination involving...... the administration of a tracer marked with (99m)Tc were included. The patients underwent a whole-body DXA scan before and within 2h after tracer injection using a GE/Lunar Prodigy scanner. Control scans were performed on 40 volunteers, who had not received any radioactive tracer. In both phantom and patient...

  12. {sup 99m}Tc(CO){sub 3}-DTMA bombesin conjugates having high affinity for the GRP receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Stephanie R. [Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States); Veerendra, Bhadrasetty [Department of Radiology, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States); Rold, Tammy L. [Department of Internal Medicine, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States); Sieckman, Gary L. [Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Hoffman, Timothy J. [Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Radiopharmaceutical Sciences Institute, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States); Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States); Jurisson, Silvia S. [Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211 (United States); Smith, Charles J. [Department of Radiology, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States); Research Division, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); University of Missouri Research Reactor Center, University of Missouri-Columbia, Columbia, MO 65211 (United States); Radiopharmaceutical Sciences Institute, University of Missouri-Columbia School of Medicine, Columbia, MO 65211 (United States)], E-mail: smithcj@health.missouri.edu

    2008-04-15

    Introduction: Targeted diagnosis of specific human cancer types continues to be of significant interest in nuclear medicine. {sup 99m}Tc is ideally suited as a diagnostic radiometal for in vivo tumor targeting due to its ideal physical characteristics and diverse labeling chemistries in numerous oxidation states. Methods: In this study, we report a synthetic approach toward design of a new tridentate amine ligand for the organometallic aqua-ion [{sup 99m}Tc(H{sub 2}O){sub 3}(CO){sub 3}]{sup +}. The new chelating ligand framework, 2-(N,N'-Bis(tert-butoxycarbonyl)diethylenetriamine) acetic acid (DTMA), was synthesized from a diethylenetriamine precursor and fully characterized by mass spectrometry and nuclear magnetic resonance spectroscopy ({sup 1}H and {sup 13}C). DTMA was conjugated to H{sub 2}N-(X)-BBN(7-14)NH{sub 2}, where X=an amino acid or aliphatic pharmacokinetic modifier and BBN=bombesin peptide, by means of solid phase peptide synthesis. DTMA-(X)-BBN(7-14)NH{sub 2} conjugates were purified by reversed-phase high-performance chromatography and characterized by electrospray-ionization mass spectrometry. Results: The new conjugates were radiolabeled with [{sup 99m}Tc(H{sub 2}O){sub 3}(CO){sub 3}]{sup +} produced via Isolink radiolabeling kits to produce [{sup 99m}Tc(CO){sub 3}-DTMA-(X)-BBN(7-14)NH{sub 2}]. Radiolabeled conjugates were purified by reversed-phase high-performance chromatography. Effective receptor binding behavior was evaluated in vitro and in vivo. Conclusions: [{sup 99m}Tc(CO){sub 3}-DTMA-(X)-BBN(7-14)NH{sub 2}] conjugates displayed very high affinity for the gastrin releasing peptide receptor in vitro and in vivo. Therefore, these conjugates hold some propensity to be investigated as molecular imaging agents that specifically target human cancers uniquely expressing the gastrin releasing peptide receptor subtypes.

  13. Tuning the Interlayer Spacing of High-Tc Bi-Based Superconductors by Intercalation: Measuring the Penetration Depth and the Two-Dimensional Superfluid Density

    Science.gov (United States)

    Baker, P. J.; Lancaster, T.; Blundell, S. J.; Pratt, F. L.; Brooks, M. L.; Kwon, S.-J.

    2009-02-01

    Substantial control of the interlayer spacing in Bi-based high temperature superconductors has been achieved through the intercalation of guest molecules between the superconducting layers. Measurements using implanted muons reveal that the penetration depth increases with increasing layer separation while Tc does not vary appreciably, demonstrating that the bulk superfluid density is not the determining factor controlling Tc. Our results strongly suggest that for Bi-based high temperature superconductors the superfluid density appearing in the Uemura scaling relation ρs∝Tc should be interpreted as the two-dimensional density within the superconducting layers, which we find to be constant for each class of system investigated.

  14. Three-Dimensional Graphene Foam-Filled Elastomer Composites with High Thermal and Mechanical Properties.

    Science.gov (United States)

    Fang, Haoming; Zhao, Yunhong; Zhang, Yafei; Ren, Yanjuan; Bai, Shu-Lin

    2017-08-09

    To meet the increasing demands for effective heat management of electronic devices, a graphene-based polymeric composite is considered to be one of the candidate materials owing to the ultrahigh thermal conductivity (TC) of graphene. However, poor graphene dispersion, low quality of exfoliated graphene, and strong phonon scattering at the graphene/matrix interface restrict the heat dissipation ability of graphene-filled composites. Here, a facile and versatile approach to bond graphene foam (GF) with polydimethylsiloxane (PDMS) is proposed, and the corresponding composite with considerable improvement in TC and insulativity is fabricated. First, three-dimensional GF was coated with polydopamine (PDA) via π-π stack and functional groups from PDA reacted with 3-aminopropyltriethoxysilane (APTS). Then, the modified GF was compressed (c-GF) to enhance density and infiltrated with PDMS to get the c-GF/PDA/APTS/PDMS composite. As a result, these processes endow the composite with high TC of in-plane 28.77 W m-1 K-1 and out-of-plane 1.62 W m-1 K-1 at 11.62 wt % GF loading. Besides, the composite manifests obvious improvement in mechanical properties, thermal stability, and insulativity compared to neat PDMS and GF/PDMS composite. An attempt to use the composite for cooling a ceramic heater is found to be successful. Above results open a way for such composites to be applied for the heat management of electronic devices.

  15. DNA adopts normal B-form upon incorporation of highly fluorescent DNA base analogue tC: NMR structure and UV-Vis spectroscopy characterization

    OpenAIRE

    Engman, K. Cecilia; Sandin, Peter; Osborne, Sadie; Brown, Tom; Billeter, Martin; Lincoln, Per; Nordén, Bengt; Albinsson, Bo; Wilhelmsson, L. Marcus

    2004-01-01

    The influence of the highly fluorescent tricyclic cytosine base analogue (tC) on duplex DNA conformation is investigated. The duplex properties are characterized by absorbance and circular dichroism (CD) for all combinations of neighbouring bases to tC, and an NMR structure is determined for one tC-containing sequence. For the oligonucleotides with one tC incorporated instead of cytosine, the melting temperature is increased on average by 2.7°C above that for the unmodified ones. CD spectra a...

  16. Higher critical current density achieved in Bi-2223 High-Tc superconductors

    Directory of Open Access Journals (Sweden)

    M.S. Shalaby

    2016-07-01

    Full Text Available Bi2Sr2Ca2Cu3Ox (Bi-2223 were prepared using a solid state reaction method at different sintering times and temperatures. Structural phase identifications have been done using X-Ray analysis and refinement by Reitveld method which proves the coexistence of Bi-2223 and Bi-2212 phases. The critical transition temperature Tc and critical current density Jc values were measured using superconducting quantum interference device magnetometer (SQUID and by the magneto-optics technique. A remarkable rapid decrease to the diamagnetic signal in the magnetization versus temperature M(T at 110 K and Jc around 1.2 × 107 A/m2 at 5 K are confirmed for the Bi-2223 compound.

  17. Experiment investigation of laser shock peening on TC6 titanium alloy to improve high cycle fatigue performance

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Xiangfan, E-mail: skingkgd@163.com; He, Weifeng; Zhou, Liucheng; Li, Qipeng; Wang, Xuede

    2014-01-31

    Laser shock peening (LSP) is an innovative surface treatment technique, and can significantly improve the fatigue performance of metallic components. In this paper, the objective of this work was to improve the fatigue resistance of TC6 titanium alloy by laser shock peening. Firstly, the effects on the microstructure and mechanical properties with different LSP impacts were investigated, which were observed and measured by X-ray diffraction (XRD), transmission electron microscope (TEM), residual stress tester and microhardness tester. Specially, nanostructure was detected in the laser-peened surface layer with multiple LSP impacts. Whereafter, a better parameter was chosen to be applied on the standard vibration fatigue specimens. Via the high-cycle vibration fatigue tests, the high cycle fatigue limits of the specimens without and with LSP were obtained and compared. The fatigue results demonstrate that LSP can effectively improve the fatigue limit of TC6 titanium alloy. The strengthening mechanism was indicated by analyzing the effects on the microstructure and mechanical properties comprehensively.

  18. Simplified Magnetically Shielded Cylinder Using Flexible Magnetic Sheets for High-Tc Superconducting Quantum Interference Device Magnetocardiogram Systems

    Science.gov (United States)

    Suzuki, Daisuke; Yokosawa, Koichi; Miyashita, Tsuyoshi; Kandori, Akihiko; Tsukada, Keiji; Tsukamoto, Akira; Arakawa, Shunsuke

    2001-10-01

    A small and simple magnetic-shielding cylinder using a new high-permeability sheet, developed for magnetic shielding, can reduce the amount of effort expended on taking magnetocardiogram (MCG) measurements. This sheet is made of a nanocrystalline soft-magnetic material (an Fe-Cu-Nb-Si-B alloy) and is flexible and easy to handle. Moreover, magnetostriction of the material is nearly zero, unlike that of the materials used in conventional magnetic shielding. The shielding cylinder is made up of three tubes of various diameters (but having the same length), placed one inside the other. The shielding cylinder is 1.0 m in diameter and 2.0 m long, and it has a shielding factor of about 35 dB at 1 Hz. The shielding cylinder was tested by measuring MCGs using a high-Tc superconducting quantum interference device (SQUID) gradiometer.

  19. The efficacy of low and high dose (99m)Tc-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism.

    Science.gov (United States)

    Gencoglu, Esra Arzu; Aktas, Ayse

    2014-01-01

    The aim of this study was to compare the efficacy of low- and high-dose (99m)Tc-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands via gamma probe in secondary hyperparathyroidism. This retrospective study was conducted using a prospective database of 59 patients who had undergone radioguided subtotal parathyroidectomy between 2004-2012. The patients were studied in 2 groups. Group 1 (n=31) received 37 MBq (99m)Tc-MIBI intravenously in the surgical room approximately 10 min before the beginning of the intervention and surgery was performed under gamma probe guidance. Group 2 (n=28) received 555 MBq (99m)Tc- MIBI intravenously 2h before surgery, which was also performed under gamma probe guidance. Intraoperative gamma probe findings, laboratory findings, and histopathological findings were evaluated together. Using acceptance of the histopathological findings as gold standard, sensitivity and specificity of intraoperative gamma probe for identifying hyperplastic parathyroid glands was 98% and 100%, respectively, in both groups. In the light of these findings, it is concluded that the low-dose (99m)Tc-MIBI protocol might be preferable for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism patients because it was observed to be as effective as the high-dose (99m)Tc-MIBI protocol. Furthermore, the low-dose protocol does not have the disadvantages that are associated with the high-dose protocol. Copyright © 2014 Elsevier España, S.L. and SEMNIM. All rights reserved.

  20. High Temperature Composite Heat Exchangers

    Science.gov (United States)

    Eckel, Andrew J.; Jaskowiak, Martha H.

    2002-01-01

    High temperature composite heat exchangers are an enabling technology for a number of aeropropulsion applications. They offer the potential for mass reductions of greater than fifty percent over traditional metallics designs and enable vehicle and engine designs. Since they offer the ability to operate at significantly higher operating temperatures, they facilitate operation at reduced coolant flows and make possible temporary uncooled operation in temperature regimes, such as experienced during vehicle reentry, where traditional heat exchangers require coolant flow. This reduction in coolant requirements can translate into enhanced range or system payload. A brief review of the approaches and challengers to exploiting this important technology are presented, along with a status of recent government-funded projects.

  1. Noise and conversion performance of a high-Tc superconducting Josephson junction mixer at 0.6 THz

    Science.gov (United States)

    Gao, Xiang; Du, Jia; Zhang, Ting; Guo, Yingjie Jay

    2017-11-01

    This letter presents both theoretical and experimental investigations on the noise and conversion performance of a high-Tc superconducting (HTS) step-edge Josephson-junction mixer at the frequency of 0.6 THz and operating temperatures of 20-40 K. Based on the Y-factor and U-factor methods, a double-sideband noise temperature of around 1000 K and a conversion gain of -3.5 dB were experimentally obtained at 20 K. At the temperature of 40 K, the measured mixer noise and conversion efficiency are around 2100 K and -10 dB, respectively. The experimental data are in good agreement with the numerical analysis results using the three-port model. A detailed performance comparison with other reported HTS terahertz mixers has confirmed the superior performance of our presented mixer device.

  2. Analysis of High Tc Superconducting Rectangular Microstrip Patches over Ground Planes with Rectangular Apertures in Substrates Containing Anisotropic Materials

    Directory of Open Access Journals (Sweden)

    Abderraouf Messai

    2013-01-01

    Full Text Available A rigorous full-wave analysis of high Tc superconducting rectangular microstrip patch over ground plane with rectangular aperture in the case where the patch is printed on a uniaxially anisotropic substrate material is presented. The dyadic Green’s functions of the considered structure are efficiently determined in the vector Fourier transform domain. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. The accuracy of the analysis is tested by comparing the computed results with measurements and previously published data for several anisotropic substrate materials. Numerical results showing variation of the resonant frequency and the quality factor of the superconducting antenna with regard to operating temperature are given. Finally, the effects of uniaxial anisotropy in the substrate on the resonant frequencies of different TM modes of the superconducting microstrip antenna with rectangular aperture in the ground plane are presented.

  3. Innate immune signaling induces high levels of TC-specific deaminase activity in primary monocyte-derived cells through expression of APOBEC3A isoforms.

    Science.gov (United States)

    Thielen, Beth K; McNevin, John P; McElrath, M Juliana; Hunt, Brook Vander Stoep; Klein, Kevin C; Lingappa, Jaisri R

    2010-09-03

    In HIV-1-infected individuals, G-to-A hypermutation is found in HIV-1 DNA isolated from peripheral blood mononuclear cells (PBMCs). These mutations are thought to result from editing by one or more host enzymes in the APOBEC3 (A3) family of cytidine deaminases, which act on CC (APOBEC3G) and TC (other A3 proteins) dinucleotide motifs in DNA (edited cytidine underlined). Although many A3 proteins display high levels of deaminase activity in model systems, only low levels of A3 deaminase activity have been found in primary cells examined to date. In contrast, here we report high levels of deaminase activity at TC motifs when whole PBMCs or isolated primary monocyte-derived cells were treated with interferon-alpha (IFNalpha) or IFNalpha-inducing toll-like receptor ligands. Induction of TC-specific deaminase activity required new transcription and translation and correlated with the appearance of two APOBEC3A (A3A) isoforms. Knockdown of A3A in monocytes with siRNA abolished TC-specific deaminase activity, confirming that A3A isoforms are responsible for all TC-specific deaminase activity observed. Both A3A isoforms appear to be enzymatically active; moreover, our mutational studies raise the possibility that the smaller isoform results from internal translational initiation. In contrast to the high levels of TC-specific activity observed in IFNalpha-treated monocytes, CC-specific activity remained low in PBMCs, suggesting that A3G deaminase activity is relatively inhibited, unlike that of A3A. Together, these findings suggest that deaminase activity of A3A isoforms in monocytes and macrophages may play an important role in host defense against viruses.

  4. High Temperature, High Power Piezoelectric Composite Transducers

    OpenAIRE

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have le...

  5. Bright upconversion luminescence and increased Tc in CaBi2Ta2O9:Er high temperature piezoelectric ceramics

    Science.gov (United States)

    Peng, Dengfeng; Wang, Xusheng; Xu, Chaonan; Yao, Xi; Lin, Jian; Sun, Tiantuo

    2012-05-01

    Er3+ doped CaBi2Ta2O9 (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er3+ doped CBT ceramics were investigated as a function of Er3+ concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from 4S3/2 and 4F9/2 to 4I15/2, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  6. TC4 AMPR BRIGHTNESS TEMPERATURE (TB) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Tropical Composition, Cloud and Climate Coupling (TC4) mission TC4 field experiment was completed during July and August 2007 based out of San Jose, Costa Rica....

  7. Bearing design for flywheel energy storage using high-TC superconductors

    Science.gov (United States)

    Hull, John R.; Mulcahy, Thomas M.

    2000-01-01

    A high temperature superconductor material bearing system (38) This system (38) includes a rotor (50) having a ring permanent magnet (60), a plurality of permanent magnets (16, 20 and 70) for interacting to generate levitation forces for the system (38). This group of magnets are a push/pull bearing (75). A high temperature superconductor structure (30) interacts with the ting permanent magnet (60) to provide stabilizing forces for the system (38).

  8. Microbial impacts on 99mTc migration through sandstone under highly alkaline conditions relevant to radioactive waste disposal.

    Science.gov (United States)

    Smith, Sarah L; Boothman, Christopher; Williams, Heather A; Ellis, Beverly L; Wragg, Joanna; West, Julia M; Lloyd, Jonathan R

    2017-01-01

    Geological disposal of intermediate level radioactive waste in the UK is planned to involve the use of cementitious materials, facilitating the formation of an alkali-disturbed zone within the host rock. The biogeochemical processes that will occur in this environment, and the extent to which they will impact on radionuclide migration, are currently poorly understood. This study investigates the impact of biogeochemical processes on the mobility of the radionuclide technetium, in column experiments designed to be representative of aspects of the alkali-disturbed zone. Results indicate that microbial processes were capable of inhibiting 99mTc migration through columns, and X-ray radiography demonstrated that extensive physical changes had occurred to the material within columns where microbiological activity had been stimulated. The utilisation of organic acids under highly alkaline conditions, generating H2 and CO2, may represent a mechanism by which microbial processes may alter the hydraulic conductivity of a geological environment. Column sediments were dominated by obligately alkaliphilic H2-oxidising bacteria, suggesting that the enrichment of these bacteria may have occurred as a result of H2 generation during organic acid metabolism. The results from these experiments show that microorganisms are able to carry out a number of processes under highly alkaline conditions that could potentially impact on the properties of the host rock surrounding a geological disposal facility for intermediate level radioactive waste. Copyright © 2016. Published by Elsevier B.V.

  9. Short-circuit experiments on a high Tc-superconducting cable conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Jensen, E.H.; Traholt, C.

    2002-01-01

    A high temperature superconductor (HTS) cable conductor (CC) with a critical current of 2.1 kA was tested over a range of short-circuit currents up to 20 kA. The duration of the short-circuit currents is 1 s. Between each short-circuit test the critical current of the HTS CC was measured in order...

  10. Theory of charge transfer at the high-Tc superconductor/electrolyte interface

    DEFF Research Database (Denmark)

    Gluzman, Sasha; Kuznetsov, Alexander M.

    1995-01-01

    We discuss the kinetics of electrochemical process on the high-T-c superconducting electrodes dependent on the type of superconductivity. The existence of the hump of an appreciable height in the temperature dependence of the current clearly points towards the BCS s-type superconductivity......) mechanism. Low-temperature tails at the current/temperature curve are also informative being determined by the electronic states within the gap typical of the unconventional d-wave pairing....

  11. Zone centre phonons in high Tc CaBi 2Sr 2Cu 2O 8

    Science.gov (United States)

    Gupta, H. C.

    1988-10-01

    The zone centre phonons have been investigated in CaBi 2Sr 2Cu 2O 8 using radial and tangential force constants. It is found that the phonons due to Bi O layers do not play an important role from the point of view of superconductivity. The calculation provides an information on the phonons which may be important for explaining the high temperature superconductivity.

  12. PEGylated N-methyl-S-methyl dithiocarbazate as a new reagent for the high-yield preparation of nitrido Tc-99m and Re-188 radiopharmaceuticals.

    Science.gov (United States)

    Boschi, Alessandra; Massi, Alessandro; Uccelli, Licia; Pasquali, Micol; Duatti, Adriano

    2010-11-01

    A novel nitrido nitrogen atom donor for the preparation of (99m)Tc and (188)Re radiopharmaceuticals containing a metal-nitrogen multiple bond is presented. HO(2)C-PEG(600)-DTCZ was obtained by conjugation of N-methyl-S-methyl dithiocarbazate [H(2)N-N(CH(3))-C(S)SCH(3), HDTCZ] with polyethylene glycol 600 (PEG(600)). Asymmetrical heterocomplexes of the type [M(N)(PNP)(B)](0/+) (M=(99m)Tc, (188)Re; PNP=diphosphine ligands, B=DBODC, DEDC, NSH, H(2)OS, CysNAc, HDTCZ) and symmetrical nitride compounds of the type [M(N)(L)(2)] (L=DEDC, DPDC) have been prepared in high yield by using the newly designed nitride nitrogen atom donor HO(2)C-PEG(600)-DTCZ. A two-step procedure was applied for preparing the above symmetrical and asymmetrical complexes. The first step involved the preliminary formation of a mixture of nitride Tc-99m or Re-188 precursors, which contained the [M≡N](2+) core, through reduction of generator-eluted (99m)Tc-pertechnetate or (188)Re-perrhenate with thin (II) chloride in the presence of HO(2)C-PEG(600)-DTCZ. In the second step, the intermediate mixture was converted either in the final mixed asymmetrical complex by the simultaneous addition of diphosphine ligand and the suitable bidentate ligand B, or in the final symmetrical complex by the only addition of the bidentate ligand L. It was also demonstrated that the novel water-soluble nitride nitrogen atom donor HO(2)C-PEG(600)-DTCZ did not show coordinating properties toward the M≡N ((99m)Tc, (188)Re) core. Biodistribution studies in rats of the hitherto unreported [(99m)Tc(N)(PNP(3))DTCZ](+) and [(99m)Tc(N)(PNP(5))DTCZ](+) complexes showed that they selectively localize in the myocardium of rats with a favourable heart-to-lung and heart-to-liver uptake ratios. In particular, the heart-to-lung and heart-to-liver uptake ratios dramatically increased in the interval between 60 and 120 min postinjection. Hence, the combination of the favourable chemical and biological properties of HO(2)C-PEG(600)-DTCZ

  13. Growth of high {Tc} superconducting fibers using a miniaturized laser-heated float zone process. Progress report, November 6, 1990--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Feigelson, R.S.; Route, R.K.; DeMattei, R.C.

    1991-12-31

    This report summarizes the progress made on the project ``Growth of High {Tc} Superconducting Fibers Using a Miniaturized Laser-Heated Float Zone Process`` during the 14 month period from Nov. 6, 1990 to Dec. 31, 1991. The studies during this period focused primarily on phase diagram studies, phase relations in the calcium aluminate system and on Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BSCCO). Some work was also done on the Advanced Fiber Growing Station. Because of the complicated phase relationships found in the incongruently melting BSCCO system, the incongruently melting CA{sub 3}Al{sub 2}O{sub 6} phase of the calcium oxide-aluminum oxide system was studied as a model material. The data obtained was in agreement with well known solidification theory. Fibers grown from calcium oxide rich sources contained calcium oxide nodules which transported from the melting source interface to the growth interface, while those grown from aluminum oxide rich sources contained continuous inclusions of a divorced eutectic. The melt compositions were also found to follow theoretical predictions. The agreement of this data with the phase diagram and solidification theory demonstrates that phase equilibrium information can be extracted from fiber growth experiments. BSCCO feed rods were made from 12 different compositions. Fibers were grown from these rods and the melts were abruptly quenched which preserves the as-grown 2212 fiber, a glassy frozen melt and the source. A future study of these sections will reveal the phase relationships that exist in the BSCCO system. Melt temperature gradients of 500--1,000 C/cm were measured near the interface in these experiments. During this reporting period, work continued on the mechanical components of the Advanced Fiber Growth Station.

  14. Delineation of target volume for radiotherapy of high-grade gliomas by {sup 99m}Tc-MIBI SPECT and MRI fusion

    Energy Technology Data Exchange (ETDEWEB)

    Krengli, M.; Manfredda, I.; Gambaro, G. [Radiotherapy, Univ. of Piemonte Orientale, Novara (Italy); Loi, G.; Brambilla, M. [Medical Physics, Hospital Maggiore della Carita, Novara (Italy); Sacchetti, G.; Inglese, E. [Nuclear Medicine, Univ. of Piemonte Orientale, Novara (Italy); Carriero, A. [Radiology, Univ. of Piemonte Orientale, Novara (Italy)

    2007-12-15

    Background and Purpose: Computed tomography (CT) and magnetic resonance imaging (MRI) are traditionally used for treatment planning of high-grade glioma. {sup 99m}Tc-methoxy-isobutyl-isonitrile (MIBI) single-photon emission computed tomography (SPECT) showed high sensitivity and specificity in literature series. In the present study, it was investigated how the information provided by {sup 99m}Tc-MIBI SPECT and MRI fusion could affect target delineation for radiotherapy of high-grade glioma. Patients and Methods: 21 patients with high-grade glioma were studied by MRI and {sup 99m}Tc-MIBI SPECT imaging. The gross tumor volume (GTV) was outlined on MRI (MRI-GTV) and SPECT images (SPECT-GTV). Three additional volumes were analyzed: the (MRI+SPECT)-GTV representing the whole amount of MRI-GTV plus SPECT-GTV, the (MRI and SPECT)-GTV identified by the overlapping region of MRI-GTV and SPECT-GTV, and the (SPECT/MRI)-GTV identified by the extension of SPECT-GTV outside MRI-GTV. Results: MRI contrast-enhanced and {sup 99m}Tc-MIBI SPECT-positive lesions were found in all 21 patients. The average SPECT-GTV was slightly larger than the average MRI-GTV, with greater difference for resected than for unresected cases. The average increment of (MRI+SPECT)-GTV compared to MRI-GTV was 33%, being significantly higher for resected than for unresected cases (p = 0.006). Conclusion: The fusion of {sup 99m}Tc-MIBI SPECT and MRI significantly affected the delineation of the target volume identified by MRI alone. (orig.)

  15. Giant flux creep through the surface barriers and the irreversibility line in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Burlachkov, L. [Bar-Ilan Univ., Ramat-Gan (Israel); Geshkenbein, V.B. [Landau Inst. for Theoretical Physics, Moscow (Russian Federation)]|[Weizmann Inst. of Science, Rehovot (Israel)]|[Theoretische Physik, ETH-Hoenggerberg, Zuerich (Switzerland); Koshelev, A.E. [Argonne National Lab., IL (United States)]|[ISSP, Chernogolovka (Russian Federation); Larkin, A.I. [Landau Inst. for Theoretical Physics, Moscow (Russian Federation)]|[Weizmann Inst. of Science, Rehovot (Israel); Vinokur, V.M. [Argonne National Lab., IL (United States)

    1994-05-01

    Magnetic flux relaxation over the surface barrier in high temperature superconductors are investigated Vortex dynamics controlled by the penetration both of pancake vortices and vortex lines are discussed. The penetration field H{sub p} for pancakes decay is exponentially with temperature. The size of the magnetization loop is determined by the decay of H{sub p} during the process of relaxation, but its shape remains unchanged. The irreversibility line associated with the pancake penetration is given by H{sub irr} {proportional_to} exp(- 2T/T{sub o}), and may lie both above and below the melting line.

  16. Nodal quasi-particles of the high-Tc superconductors as carriers of heat

    Directory of Open Access Journals (Sweden)

    K. Behnia

    2006-09-01

    Full Text Available   In the quest for understanding correlated electrons, high-temperature superconductivity remains a formidable challenge and a source of insight. This paper briefly recalls the central achievement by the study of heat transport at low temperatures. At very low temperatures, nodal quasi-particles of the d-wave superconducting gap become the main carriers of heat. Their thermal conductivity is unaffected by disorder and reflects the fine structure of the superconducting gap. This finding had led to new openings in the exploration of other unconventional superconductors

  17. Future prospects of high Tc superconductors-coated conductors and their applications

    Science.gov (United States)

    Shiohara, Yuh; Yoshizumi, Masateru; Takagi, Yuji; Izumi, Teruo

    2013-01-01

    The research and development of high-temperature superconducting wires, especially yttrium-based coated conductors (CCs), and their energy applications have been expected to reduce CO2 emissions. This article reviews recent progress in this area, mainly focusing on the results obtained by national projects in Japan. The Ic (critical current) × L (wire length) value of CCs has been improved to reach 466,752 A m (572 A/cm-W, 816 m), which exceeds that of Bi-system wires. CCs have also been improved in terms of in-field performance and AC loss reduction to meet market requirements. Power applications such as superconducting magnetic energy storage (SMES) systems, power cables and transformers have been developed using CCs in the current project. Because of fundamental research on high-capacity power cables, a low AC loss of 0.8 W/m-ph at 3 kA and 73.7 K was achieved. System design and fundamental research were performed on a 2GJ-class SMES system and a 20 MVA-class transformer. Based on the technologies developed by the end of the current project (FY2012), the innovation process of those applications will reach the implementation stage, where the long-term reliability tests will be performed. The process is expected to reach the penetration and propagation stage around 2020.

  18. A New Landscape of Multiple Dispersion Kinks in a High-TcCuprate Superconductor.

    Science.gov (United States)

    Anzai, H; Arita, M; Namatame, H; Taniguchi, M; Ishikado, M; Fujita, K; Ishida, S; Uchida, S; Ino, A

    2017-07-06

    Conventional superconductivity is caused by electron-phonon coupling. The discovery of high-temperature superconductors raised the question of whether such strong electron-phonon coupling is realized in cuprates. Strong coupling with some collective excitation mode has been indicated by a dispersion "kink". However, there is intensive debate regarding whether the relevant coupling mode is a magnetic resonance mode or an oxygen buckling phonon mode. This ambiguity is a consequence of the energy of the main prominent kink. Here, we show a new landscape of dispersion kinks. We report that heavily overdoping a Bi 2 Sr 2 CaCu 2 O 8+δ superconductor results in a decline of the conventional main kink and a rise of another sharp kink, along with substantial energy shifts of both. Notably, the latter kink can be ascribed only to an oxygen-breathing phonon. Hence, the multiple phonon branches provide a consistent account of our data set on the multiple kinks. Our results suggest that strong electron-phonon coupling and its dramatic change should be incorporated into or reconciled with scenarios for the evolution of high-T c superconductivity.

  19. Fabrication and characterization of electrically tunable high-Tc superconducting resonators incorporating barium strontium titanate as a tuning material

    Science.gov (United States)

    Lee, E.-H.; Sok, J.; Park, S.-J.; Lee, J.-S.; Song, I.-H.; Kwak, J.; Jung, K.-R.; Kim, J.-Y.; Yoon, S.-Y.; Jeon, D. Y.

    1999-11-01

    We have made the electrically tunable microstrip resonators by using both high-Tc superconducting and dielectric films. The two-pole resonators employ a dielectric barium strontium titanate film on their centre in the form of flip chip. The superconducting YBa2Cu3Oy (YBCO) and dielectric Ba0.1Sr0.9TiO3 were deposited on the CeO2-buffered sapphire substrate and LaAlO3 substrate, respectively, by a pulsed laser deposition technique. Variations of the relative permittivity, icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="TOP"/>r, and dielectric loss tangent, tanicons/Journals/Common/delta" ALT="delta" ALIGN="TOP"/>, of the Ba0.1Sr0.9TiO3 were studied as a function of the applied dc bias at liquid-nitrogen temperature. The tunability, defined as C(0 V)/C(100 V), and loss tangent of the resonators were measured to be ~1.9 and 1.5 × 10-2 (at 100 V), respectively.

  20. Superstrate loading effects on the resonant characteristics of high Tc superconducting circular patch printed on anisotropic materials

    Science.gov (United States)

    Bedra, Sami; Bedra, Randa; Benkouda, Siham; Fortaki, Tarek

    2017-12-01

    In this paper, the effects of both anisotropies in the substrate and superstrate loading on the resonant frequency and bandwidth of high-Tc superconducting circular microstrip patch in a substrate-superstrate configuration are investigated. A rigorous analysis is performed using a dyadic Galerkin's method in the vector Hankel transform domain. Galerkin's procedure is employed in the spectral domain where the TM and TE modes of the cylindrical cavity with magnetic side walls are used in the expansion of the disk current. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. London's equations and the two-fluid model of Gorter and Casimir are used in the calculation of the complex surface impedance of the superconducting circular disc. The accuracy of the analysis is tested by comparing the computed results with previously published data for several anisotropic substrate-superstrate materials. Good agreement is found among all sets of results. The numerical results obtained show that important errors can be made in the computation of the resonant frequencies and bandwidths of the superconducting resonators when substrate dielectric anisotropy, and/or superstrate anisotropy are ignored. Other theoretical results obtained show that the superconducting circular microstrip patch on anisotropic substrate-superstrate with properly selected permittivity values along the optical and the non-optical axes combined with optimally chosen structural parameters is more advantageous than the one on isotropic substrate-superstrate by exhibiting wider bandwidth characteristic.

  1. Monitoring of Spectral Map Changes from Normal State to Superconducting State in High-TC Superconductor Films Using Raman Imaging

    Directory of Open Access Journals (Sweden)

    J. L. González-Solís

    2015-01-01

    Full Text Available We have explored the chemical structure of TlBa2Ca2Cu3O9 high-TC superconductor films with Tl-1223 phase to monitor spectral map changes from normal state to superconducting state using the technique of Raman imaging. Raman images were performed for 12 different temperatures in the 77–293 K range. At room temperature, the Raman images were characterized by a single color but as the temperature dropped a new color appeared and when the temperature of 77 K is reached and the superconducting state is assured, the Raman images were characterized by the red, green, and blue colors. Our study could suggest that the superconducting state emerged around 133 K, in full agreement with those reported in the literature. A cross-checking was done applying principal component analysis (PCA to other sets of Raman spectra of our films measured at different temperatures. PCA result showed that the spectra can be grouped into two temperature ranges, one in the 293–153 K range and the other in the 133–77 K range suggesting that transition to the superconducting state occurred at some temperature around 133 K. This is the first report of preliminary results evaluating the usefulness of Raman imaging in determination of transition temperature of superconductor films.

  2. Low-frequency noise in high-(Tc) superconductor Josephson junctions, SQUIDs, and magnetometers

    Science.gov (United States)

    Miklich, A. H.

    1994-05-01

    Design and performance of high-T(sub c) dc superconducting quantum interference devices (SQUID's), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUID's; this suggests a poorly connected interface at the grain boundary junction. SQUID's from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5 x 10(exp -30) J Hz(exp -1) at 1 Hz is reported. Magnetometers in which a (9 mm)(exp 2) pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz(exp -1/2) down to frequencies below 1 Hz, improving to 39 fT Hz(exp -1/2) at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz(exp -1/2) in the white noise region is reported with a (10 mm)(exp 2) pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz(exp -1/2). High-T(sub c) SQUID's exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV Hz(exp -1/2) at 10 Hz (24 pV Hz(exp -1/2) at 1 Hz) is described.

  3. Magneto-optical studies of magnetization processes in high-Tc superconductors structure.

    Energy Technology Data Exchange (ETDEWEB)

    Vlasko-Vlasox, V. K.

    1998-12-02

    Magneto-optical imaging is a powerful tool for nondestructive quality control and scientific research through visualization of magnetic fields around any magnetic flux or current carrying sample. It allows real time observations of domain structures and their transformations in magnetics, static and dynamic field patterns due to inhomogeneous currents in electric circuits and superconductors, and reveals distortions of the fields due to defects. In addition to qualitative pictures showing different details in the intensities of the magneto-optical images, one can obtain quantitative maps of field distributions and retrieve values of the underlying currents or magnetization variations. In this review we discuss the advantages of magneto-optics for studies of superconductors, show its place among other techniques, and report recent results in magneto-optical investigations of high temperature superconductors (HTS).

  4. Compensated electron and hole pickets in an underdoped high Tc superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Neil [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory; Sebastian, Suchitra E [CAMBRIDGE U; Goddard, P A [U OF OXFORD; Liang, Ruixing [U BRITISH COLUMBIA; Bonn, D A [U BRITISH COLUMBIA; Hardy, W N [U BRITISH COLUMBIA; Andersen, O K [MAX PLANCK INST.; Lonzarich, G G [CAMBRIDGE U

    2010-01-01

    Important to the question of high temperature superconductivity is whether bound fermionic pairs with zero or finite momentum - exhibiting bosonic physics - are involved. Here we use angle-dependent magnetic quantum oscillation measurements in underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} to reveal two significantly differently corrugated small sections of Fermi surface, identifying them as comprising opposite carriers located at different locations of the Brillouin zone. The surprising finding that these disproportionately heavy small pockets are equal in size indicates they are prone to a finite momentum excitonic insulator instability. We discuss the possibility that reducing the doping drives YBa{sub 2}Cu{sub 3}O{sub 6+x} closer to an instability of this nature, its ultimate realization occuring at the metal-insulator quantum critical point, accompanied by a potential enhancement of superconducting transition temperatures.

  5. Towards resolution of the Fermi surface in underdoped high-Tc superconductors.

    Science.gov (United States)

    Sebastian, Suchitra E; Harrison, Neil; Lonzarich, Gilbert G

    2012-10-01

    We survey recent experimental results including quantum oscillations and complementary measurements probing the electronic structure of underdoped cuprates, and theoretical proposals to explain them. We discuss quantum oscillations measured at high magnetic fields in the underdoped cuprates that reveal a small Fermi surface section, comprising quasiparticles that obey Fermi-Dirac statistics, unaccompanied by other states of comparable thermodynamic mass at the Fermi level. The location of the observed Fermi surface section at the nodes is indicated by a body of evidence including the collapse in Fermi velocity measured by quantum oscillations, which is found to be associated with the nodal density of states observed in angular resolved photoemission, the persistence of quantum oscillations down to low fields in the vortex state, the small value of density of states from heat capacity and the multiple frequency quantum oscillation pattern consistent with nodal magnetic breakdown of bilayer-split pockets. A nodal Fermi surface pocket is further consistent with the observation of a density of states at the Fermi level concentrated at the nodes in photoemission experiments, and the antinodal pseudogap observed by photoemission, optical conductivity, nuclear magnetic resonance (NMR) Knight shift, as well as other complementary diffraction, transport and thermodynamic measurements. One of the possibilities considered is that the small Fermi surface pockets observed at high magnetic fields can be understood in terms of Fermi surface reconstruction by a form of small wavevector charge order, observed over long lengthscales in experiments such as NMR and x-ray scattering, potentially accompanied by an additional mechanism to gap the antinodal density of states.

  6. A magnetic levitation rotating plate model based on high-Tc superconducting technology

    Science.gov (United States)

    Zheng, Jun; Li, Jipeng; Sun, Ruixue; Qian, Nan; Deng, Zigang

    2017-09-01

    With the wide requirements of the training aids and display models of science, technology and even industrial products for the public like schools, museums and pleasure grounds, a simple-structure and long-term stable-levitation technology is needed for these exhibitions. Opportunely, high temperature superconducting (HTS) technology using bulk superconductors indeed has prominent advantages on magnetic levitation and suspension for its self-stable characteristic in an applied magnetic field without any external power or control. This paper explores the feasibility of designing a rotatable magnetic levitation (maglev) plate model with HTS bulks placed beneath a permanent magnet (PM) plate. The model is featured with HTS bulks together with their essential cryogenic equipment above and PMs below, therefore it eliminates the unclear visual effects by spray due to the low temperature coolant such as liquid nitrogen (LN2) and additional levitation weight of the cryogenic equipment. Besides that, a matched LN2 automation filling system is adopted to help achieving a long-term working state of the rotatable maglev plate. The key low-temperature working condition for HTS bulks is maintained by repeatedly opening a solenoid valve and automatically filling LN2 under the monitoring of a temperature sensor inside the cryostat. With the support of the cryogenic devices, the HTS maglev system can meet all requirements of the levitating display model for exhibitions, and may enlighten the research work on HTS maglev applications.

  7. Nonlinear vibration behaviors of high-Tc superconducting bulks in an applied permanent magnetic array field

    Science.gov (United States)

    Li, Jipeng; Li, Haitao; Zheng, Jun; Zheng, Botian; Huang, Huan; Deng, Zigang

    2017-06-01

    The nonlinear vibration of high temperature superconducting (HTS) bulks in an applied permanent magnetic array (Halbach array) field, as a precondition for commercial application to HTS maglev train and HTS bearing, is systematically investigated. This article reports the actual vibration rules of HTS bulks from three aspects. First, we propose a new numerical model to simplify the calculation of levitation force. This model could provide precise simulations, especially the estimation of eigenfrequency. Second, an approximate analytic solution of the vibration of the HTS bulks is obtained by using the method of harmonic balance. Finally, to verify the results mentioned above, we measure the vertical vibration acceleration signals of an HTS maglev model, consisting of eight YBaCuO bulks, oscillating freely above a Halbach array with large displacement excitation. Higher order harmonic components, which indicate the nonlinear vibration phenomenon, are detected in the responses. All the three results are compared and agreed well with each other. This study combines the experimental and theoretical analyses and provides a deep understanding of the physical phenomenon of the nonlinear vibration and is meaningful for the vibration control of the relevant applications.

  8. High Density, Insensitive Oxidizer With RDX Performance Final Report CRADA No. TC02178.0

    Energy Technology Data Exchange (ETDEWEB)

    Pagoria, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Preda, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-25

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Physical Sciences, Inc. (PSI), to develop a synthesis and evaluate a novel high density, insensitive oxidizer with RDX performance. This CRADA resulted from the award of a Phase I STTR ("STTR") from DOD. In recent years, the synthesis of new energetic heterocyclic compounds to replace the energetic materials currently in the stockpile has received a great amount of attention. The Office of the Secretary of Defense has identified that there is a need to incorporate new energetic materials in current and future weapon systems in an effort to increase performance and decrease sensitivity. For many of the future weapon systems, incorporation of energetic compounds currently in the stockpile will not provide the desired performance and sensitivity goals. The success of this CRADA may lead to a Phase I option STTR from DOD and to a Phase II STTR from DOD. The goal of this CRADA was to produce and test a novel oxidizer, 2,5,8-trinitroheptazine (TNH).

  9. Impurity band Mott insulators: a new route to high Tc superconductivity

    Directory of Open Access Journals (Sweden)

    Ganapathy Baskaran

    2008-01-01

    Full Text Available Last century witnessed the birth of semiconductor electronics and nanotechnology. The physics behind these revolutionary developments is certain quantum mechanical behaviour of 'impurity state electrons' in crystalline 'band insulators', such as Si, Ge, GaAs and GaN, arising from intentionally added (doped impurities. The present article proposes that certain collective quantum behaviour of these impurity state electrons, arising from Coulomb repulsions, could lead to superconductivity in a parent band insulator, in a way not suspected before. Impurity band resonating valence bond theory of superconductivity in boron doped diamond, recently proposed by us, suggests possibility of superconductivity emerging from impurity band Mott insulators. We use certain key ideas and insights from the field of high-temperature superconductivity in cuprates and organics. Our suggestion also offers new possibilities in the field of semiconductor electronics and nanotechnology. The current level of sophistication in solid state technology and combinatorial materials science is very well capable of realizing our proposal and discover new superconductors.

  10. Design report of Task 7.5, High-Tc Link

    CERN Document Server

    Ballarino, A

    2012-01-01

    The proposal of developing High Temperature Superconducting (HTS) cables derives from the potential of the application of HTS in the powering system of the LHC accelerator [1]. The powering of the LHC magnets is today performed via power converters located in tunnel alcoves. Warm cables connect the power converters to the leads integrated in cryostats in line with the beam. The use of superconducting links allows the removal of the powering equipment from the radiation areas in the tunnel to remote radiation-free locations. As a result, one can ensure safer long-term operation of the equipment as well as easier access - in non radiation zones - of personnel to power converters, current leads and related control apparatus for the maintenance, repair, diagnostic and other interventions. The FP7 activity performed within the Task 7.5 aims at the development of a superconducting link of the type that could be applied in the LHC at P3 or P7. It consists of 48 cables, rated at 600 A – DC, and developed for the po...

  11. Phonon characteristics of high {Tc} superconductors from neutron Doppler broadening measurements

    Energy Technology Data Exchange (ETDEWEB)

    Trela, W.J.; Kwei, G.H.; Lynn, J.E. [Los Alamos National Lab., NM (United States); Meggers, K. [Univ. of Kiel (Germany)

    1994-12-01

    Statistical information on the phonon frequency spectrum of materials can be measured by neutron transmission techniques if they contain nuclei with low energy resonances, narrow enough to be Doppler-broadened, in their neutron cross sections. The authors have carried out some measurements using this technique for materials of the lanthanum barium cuprate class, La{sub 2{minus}x}Ba{sub x}CuO{sub 4}. Two samples with slightly different concentrations of oxygen, one being superconductive, the other not, were examined. Pure lanthanum cuprate was also measured. Lanthanum, barium and copper all have relatively low energy narrow resonances. Thus it should be possible to detect differences in the phonons carried by different kinds of atom in the lattice. Neutron cross section measurements have been made with high energy resolution and statistical precision on the 59m flight path of LANSCE, the pulsed spallation neutron source at Los Alamos National Laboratory. Measurements on all three materials were made over a range of temperatures from 15K to 300K, with small steps through the critical temperature region near 27K. No significant changes in the mean phonon energy of the lanthanum atoms were observed near the critical temperature of the super-conducting material. It appears however that the mean phonon energy of lanthanum in the superconductor is considerably higher than that in the non-superconductors. The samples used in this series of experiments were too thin in barium and copper to determine anything significant about their phonon spectra.

  12. Healing Effect of Controlled Anti-Electromigration on Conventional and High-Tc Superconducting Nanowires.

    Science.gov (United States)

    Baumans, Xavier D A; Lombardo, Joseph; Brisbois, Jérémy; Shaw, Gorky; Zharinov, Vyacheslav S; He, Ge; Yu, Heshan; Yuan, Jie; Zhu, Beiyi; Jin, Kui; Kramer, Roman B G; de Vondel, Joris Van; Silhanek, Alejandro V

    2017-07-01

    The electromigration process has the potential capability to move atoms one by one when properly controlled. It is therefore an appealing tool to tune the cross section of monoatomic compounds with ultimate resolution or, in the case of polyatomic compounds, to change the stoichiometry with the same atomic precision. As demonstrated here, a combination of electromigration and anti-electromigration can be used to reversibly displace atoms with a high degree of control. This enables a fine adjustment of the superconducting properties of Al weak links, whereas in Nb the diffusion of atoms leads to a more irreversible process. In a superconductor with a complex unit cell (La2-x Cex CuO4 ), the electromigration process acts selectively on the oxygen atoms with no apparent modification of the structure. This allows to adjust the doping of this compound and switch from a superconducting to an insulating state in a nearly reversible fashion. In addition, the conditions needed to replace feedback controlled electromigration by a simpler technique of electropulsing are discussed. These findings have a direct practical application as a method to explore the dependence of the characteristic parameters on the exact oxygen content and pave the way for a reversible control of local properties of nanowires. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-Tc superconductors

    Science.gov (United States)

    Takei, So; Fregoso, Benjamin M.; Galitski, Victor; Das Sarma, S.

    2013-01-01

    The possibility of inducing topological superconductivity with cuprate high-temperature superconductors (HTSC) is studied for various heterostructures. We first consider a ballistic planar junction between a HTSC and a metallic ferromagnet. We assume that inversion symmetry breaking at the tunnel barrier gives rise to Rashba spin-orbit coupling in the barrier and allows equal-spin triplet superconductivity to exist in the ferromagnet. Bogoliubov-de Gennes equations are obtained by explicitly modeling the barrier and taking account of the transport anisotropy in the HTSC. By making use of the self-consistent boundary conditions and solutions for the barrier and HTSC regions, an effective equation of motion for the ferromagnet is obtained where Andreev scattering at the barrier is incorporated as a boundary condition for the ferromagnetic region. For a ferromagnet layer deposited on a (100) facet of the HTSC, triplet p-wave superconductivity is induced. For the layer deposited on a (110) facet, the induced gap does not have the p-wave orbital character, but has an even orbital symmetry and an odd dependence on energy. For the layer on the (001) facet, an exotic f-wave superconductivity is induced. We also consider the induced triplet gap in a one-dimensional half-metallic nanowire deposited on a (001) facet of a HTSC. Due to the breaking of translational symmetry in the direction perpendicular to the wire axis, the expression for the gap receives contributions from different perpendicular momentum eigenstates in the superconductor. We find that for a wire axis along the a axis, these different contributions constructively interfere and give rise to a robust triplet p-wave gap. For a wire oriented 45∘ away from the a axis, the different contributions destructively interfere and the induced triplet p-wave gap vanishes. For the appropriately oriented wire, the induced p-wave gap may give rise to Majorana fermions at the ends of the half-metallic wire. In light of the

  14. High-frequency behavior of magnetic composites

    Science.gov (United States)

    Lagarkov, Andrey N.; Rozanov, Konstantin N.

    2009-07-01

    The paper reviews recent progress in the field of microwave magnetic properties of composites. The problem under discussion is developing composites with high microwave permeability that are needed in many applications. The theory of magnetic composites is briefly sketched with the attention paid to the laws governing the magnetic frequency dispersion in magnetic materials and basic mixing rules for composites. Recent experimental reports on the microwave performance of magnetic composites, as well as data on the agreement of the mixing rules with the measured permeability of composites that are available from the literature are discussed. From the data, a conclusion is made that the validity of a mixing rule is determined by the permeability contrast in the composite, i.e., the difference between permeability of inclusions and that of the host matrix. When the contrast is low, the Maxwell Garnet mixing rule is frequently valid. When the contrast is high, which is of the most interest for obtaining high microwave permeability of a composite, no conventionally accepted theory is capable of accurately predicting the permeability of the composites. Therefore, the mixing rules do not allow the microwave properties of magnetic composites to be predicted when the permeability of inclusions is high, that is the case of the most interest. Because of that, general limitations to the microwave performance of composites are of importance. In particular, an important relation constraining the microwave permeability of composites follows from Kittel's theory of ferromagnetic resonance and analytical properties of frequency dependence of permeability. Another constraint concerning the bandwidth of electromagnetic wave absorbers follows from the Kramers-Kronig relations for the reflection coefficient. The constraints are of importance in design and analysis of electromagnetic wave absorbers and other devices that employ the microwave magnetic properties of composites, such as

  15. DNA adopts normal B-form upon incorporation of highly fluorescent DNA base analogue tC: NMR structure and UV-Vis spectroscopy characterization.

    Science.gov (United States)

    Engman, K Cecilia; Sandin, Peter; Osborne, Sadie; Brown, Tom; Billeter, Martin; Lincoln, Per; Nordén, Bengt; Albinsson, Bo; Wilhelmsson, L Marcus

    2004-01-01

    The influence of the highly fluorescent tricyclic cytosine base analogue (tC) on duplex DNA conformation is investigated. The duplex properties are characterized by absorbance and circular dichroism (CD) for all combinations of neighbouring bases to tC, and an NMR structure is determined for one tC-containing sequence. For the oligonucleotides with one tC incorporated instead of cytosine, the melting temperature is increased on average by 2.7 degrees C above that for the unmodified ones. CD spectra are practically identical for modified and unmodified sequences, indicating an unperturbed B-DNA conformation. The NMR structure determination of the self-complementary sequence 5'-CTC(tC)ACGTGGAG shows a DNA conformation consistent with B-form for the whole duplex. The root-mean-square distance for the nucleotides of the eight central base pairs between the 10 structures with lowest CYANA target functions and a mean structure is 0.45 +/- 0.17 A. The NMR data confirm correct base pairing for tC by the observation of both intrastrand and interstrand imino proton NOEs. Altogether, this suggests that tC works well as a cytosine analogue, i.e. it is situated in the base stack, forming hydrogen bonds with G in the complementary strand, without distorting the DNA backbone conformation. This first example of an artificial, highly fluorescent DNA base that does not perturb the DNA conformation could have valuable applications for the study of the structure and dynamics of nucleic acid systems.

  16. Thermomechanics of composite structures under high temperatures

    CERN Document Server

    Dimitrienko, Yu I

    2016-01-01

    This pioneering book presents new models for the thermomechanical behavior of composite materials and structures taking into account internal physico-chemical transformations such as thermodecomposition, sublimation and melting at high temperatures (up to 3000 K). It is of great importance for the design of new thermostable materials and for the investigation of reliability and fire safety of composite structures. It also supports the investigation of interaction of composites with laser irradiation and the design of heat-shield systems. Structural methods are presented for calculating the effective mechanical and thermal properties of matrices, fibres and unidirectional, reinforced by dispersed particles and textile composites, in terms of properties of their constituent phases. Useful calculation methods are developed for characteristics such as the rate of thermomechanical erosion of composites under high-speed flow and the heat deformation of composites with account of chemical shrinkage. The author expan...

  17. Aqueous (99)Tc, (129)I and (137)Cs removal from contaminated groundwater and sediments using highly effective low-cost sorbents.

    Science.gov (United States)

    Li, Dien; Kaplan, Daniel I; Knox, Anna S; Crapse, Kimberly P; Diprete, David P

    2014-10-01

    Technetium-99 ((99)Tc), iodine-129 ((129)I), and cesium-137 ((137)Cs) are among the key risk-drivers for environmental cleanup. Immobilizing these radionuclides, especially TcO4(-) and I(-), has been challenging. TcO4(-) and I(-) bind very weakly to most sediments, such that distribution coefficients (Kd values; radionuclide concentration ratio of solids to liquids) are typically organoclays sorbed large amounts of TcO4(-) (Kd > 1 × 10(5) mL/g), I(-) (Kd ≥ 1 × 10(4) mL/g), and Cs(+) (Kd > 1 × 10(3) mL/g) and also demonstrated a largely irreversible binding of the radionuclides. Activated carbon GAC 830 was effective at sorbing TcO4(-) (Kd > 1 × 10(5) mL/g) and I(-) (Kd = 6.9 × 10(3) mL/g), while a surfactant modified chabazite was effective at sorbing TcO4(-) (Kd > 2.5 × 10(4) mL/g) and Cs(+) (Kd > 6.5 × 10(3) mL/g). Several sorbents were effective for only one radionuclide, e.g., modified zeolite Y had TcO4(-)Kd > 2.3 × 10(5) mL/g, AgS had I(-) Kd = 2.5 × 10(4) mL/g, and illite, chabazite, surfactant modified clinoptilolite, and thiol-SAMMS had Cs(+)Kd > 10(3) mL/g. These low-cost and high capacity sorbents may provide a sustainable solution for environmental remediation. Copyright © 2014. Published by Elsevier Ltd.

  18. High-Performance Cellulose Nanofibril Composite Films

    Science.gov (United States)

    Yan Qing; Ronald Sabo; Yiqiang Wu; Zhiyong Cai

    2012-01-01

    Cellulose nanofibril/phenol formaldehyde (CNF/PF) composite films with high work of fracture were prepared by filtering a mixture of 2,2,6,6tetramethylpiperidine-1-oxyl (TEMPO) oxidized wood nanofibers and water-soluble phenol formaldehyde with resin contents ranging from 5 to 20 wt%, followed by hot pressing. The composites were characterized by tensile testing,...

  19. High School Economic Composition and College Persistence

    Science.gov (United States)

    Niu, Sunny X.; Tienda, Marta

    2013-01-01

    Using a longitudinal sample of Texas high school seniors of 2002 who enrolled in college within the calendar year of high school graduation, we examine variation in college persistence according to the economic composition of their high schools, which serves as a proxy for unmeasured high school attributes that are conductive to postsecondary…

  20. Highly thermal-stable ferromagnetism by a natural composite.

    Science.gov (United States)

    Ma, Tianyu; Gou, Junming; Hu, Shanshan; Liu, Xiaolian; Wu, Chen; Ren, Shuai; Zhao, Hui; Xiao, Andong; Jiang, Chengbao; Ren, Xiaobing; Yan, Mi

    2017-01-18

    All ferromagnetic materials show deterioration of magnetism-related properties such as magnetization and magnetostriction with increasing temperature, as the result of gradual loss of magnetic order with approaching Curie temperature TC. However, technologically, it is highly desired to find a magnetic material that can resist such magnetism deterioration and maintain stable magnetism up to its TC, but this seems against the conventional wisdom about ferromagnetism. Here we show that a Fe-Ga alloy exhibits highly thermal-stable magnetization up to the vicinity of its TC, 880 K. Also, the magnetostriction shows nearly no deterioration over a very wide temperature range. Such unusual behaviour stems from dual-magnetic-phase nature of this alloy, in which a gradual structural-magnetic transformation occurs between two magnetic phases so that the magnetism deterioration is compensated by the growth of the ferromagnetic phase with larger magnetization. Our finding may help to develop highly thermal-stable ferromagnetic and magnetostrictive materials.

  1. High-strain composites and dual-matrix composite structures

    Science.gov (United States)

    Maqueda Jimenez, Ignacio

    Most space applications require deployable structures due to the limiting size of current launch vehicles. Specifically, payloads in nanosatellites such as CubeSats require very high compaction ratios due to the very limited space available in this typo of platform. Strain-energy-storing deployable structures can be suitable for these applications, but the curvature to which these structures can be folded is limited to the elastic range. Thanks to fiber microbuckling, high-strain composite materials can be folded into much higher curvatures without showing significant damage, which makes them suitable for very high compaction deployable structure applications. However, in applications that require carrying loads in compression, fiber microbuckling also dominates the strength of the material. A good understanding of the strength in compression of high-strain composites is then needed to determine how suitable they are for this type of application. The goal of this thesis is to investigate, experimentally and numerically, the microbuckling in compression of high-strain composites. Particularly, the behavior in compression of unidirectional carbon fiber reinforced silicone rods (CFRS) is studied. Experimental testing of the compression failure of CFRS rods showed a higher strength in compression than the strength estimated by analytical models, which is unusual in standard polymer composites. This effect, first discovered in the present research, was attributed to the variation in random carbon fiber angles respect to the nominal direction. This is an important effect, as it implies that microbuckling strength might be increased by controlling the fiber angles. With a higher microbuckling strength, high-strain materials could carry loads in compression without reaching microbuckling and therefore be suitable for several space applications. A finite element model was developed to predict the homogenized stiffness of the CFRS, and the homogenization results were used in

  2. Enhancing electric-field control of ferromagnetism through nanoscale engineering of high-Tc MnxGe1−x nanomesh

    Science.gov (United States)

    Nie, Tianxiao; Tang, Jianshi; Kou, Xufeng; Gen, Yin; Lee, Shengwei; Zhu, Xiaodan; He, Qinglin; Chang, Li-Te; Murata, Koichi; Fan, Yabin; Wang, Kang L.

    2016-01-01

    Voltage control of magnetism in ferromagnetic semiconductor has emerged as an appealing solution to significantly reduce the power dissipation and variability beyond current CMOS technology. However, it has been proven to be very challenging to achieve a candidate with high Curie temperature (Tc), controllable ferromagnetism and easy integration with current Si technology. Here we report the effective electric-field control of both ferromagnetism and magnetoresistance in unique MnxGe1−x nanomeshes fabricated by nanosphere lithography, in which a Tc above 400 K is demonstrated as a result of size/quantum confinement. Furthermore, by adjusting Mn doping concentration, extremely giant magnetoresistance is realized from ∼8,000% at 30 K to 75% at 300 K at 4 T, which arises from a geometrically enhanced magnetoresistance effect of the unique mesh structure. Our results may provide a paradigm for fundamentally understanding the high Tc in ferromagnetic semiconductor nanostructure and realizing electric-field control of magnetoresistance for future spintronic applications. PMID:27762320

  3. Large-moment antiferromagnetic order in overdoped high-Tc superconductor 154SmFeAsO1-x D x.

    Science.gov (United States)

    Iimura, Soshi; Okanishi, Hiroshi; Matsuishi, Satoru; Hiraka, Haruhiro; Honda, Takashi; Ikeda, Kazutaka; Hansen, Thomas C; Otomo, Toshiya; Hosono, Hideo

    2017-05-30

    In iron-based superconductors, high critical temperature (Tc) superconductivity over 50 K has only been accomplished in electron-doped hREFeAsO (hRE is heavy rare earth (RE) element). Although hREFeAsO has the highest bulk Tc (58 K), progress in understanding its physical properties has been relatively slow due to difficulties in achieving high-concentration electron doping and carrying out neutron experiments. Here, we present a systematic neutron powder diffraction study of 154SmFeAsO1-x D x , and the discovery of a long-range antiferromagnetic ordering with x ≥ 0.56 (AFM2) accompanying a structural transition from tetragonal to orthorhombic. Surprisingly, the Fe magnetic moment in AFM2 reaches a magnitude of 2.73 μB/Fe, which is the largest in all nondoped iron pnictides and chalcogenides. Theoretical calculations suggest that the AFM2 phase originates in kinetic frustration of the Fe-3dxy orbital, in which the nearest-neighbor hopping parameter becomes zero. The unique phase diagram, i.e., highest-Tc superconducting phase adjacent to the strongly correlated phase in electron-overdoped regime, yields important clues to the unconventional origins of superconductivity.

  4. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

    2014-01-01

    Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

  5. PEGylated N-methyl-S-methyl dithiocarbazate as a new reagent for the high-yield preparation of nitrido Tc-99m and Re-188 radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Boschi, Alessandra, E-mail: alessandra.boschi@unife.i [Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara (Italy); Massi, Alessandro [Department of Chemistry, University of Ferrara, 44100 Ferrara (Italy); Uccelli, Licia; Pasquali, Micol; Duatti, Adriano [Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, 44100 Ferrara (Italy)

    2010-11-15

    A novel nitrido nitrogen atom donor for the preparation of {sup 99m}Tc and {sup 188}Re radiopharmaceuticals containing a metal-nitrogen multiple bond is presented. HO{sub 2}C-PEG{sub 600}-DTCZ was obtained by conjugation of N-methyl-S-methyl dithiocarbazate [H{sub 2}N-N(CH{sub 3})-C({identical_to}S)SCH{sub 3}, HDTCZ] with polyethylene glycol 600 (PEG{sub 600}). Asymmetrical heterocomplexes of the type [M(N)(PNP)(B)]{sup 0/+} (M={sup 99m}Tc, {sup 188}Re; PNP=diphosphine ligands, B=DBODC, DEDC, NSH, H{sub 2}OS, CysNAc, HDTCZ) and symmetrical nitride compounds of the type [M(N)(L){sub 2}] (L=DEDC, DPDC) have been prepared in high yield by using the newly designed nitride nitrogen atom donor HO{sub 2}C-PEG{sub 600}-DTCZ. A two-step procedure was applied for preparing the above symmetrical and asymmetrical complexes. The first step involved the preliminary formation of a mixture of nitride Tc-99m or Re-188 precursors, which contained the [M{identical_to}N]{sup 2+} core, through reduction of generator-eluted {sup 99m}Tc-pertechnetate or {sup 188}Re-perrhenate with thin (II) chloride in the presence of HO{sub 2}C-PEG{sub 600}-DTCZ. In the second step, the intermediate mixture was converted either in the final mixed asymmetrical complex by the simultaneous addition of diphosphine ligand and the suitable bidentate ligand B, or in the final symmetrical complex by the only addition of the bidentate ligand L. It was also demonstrated that the novel water-soluble nitride nitrogen atom donor HO{sub 2}C-PEG{sub 600}-DTCZ did not show coordinating properties toward the M{identical_to}N ({sup 99m}Tc, {sup 188}Re) core. Biodistribution studies in rats of the hitherto unreported [{sup 99m}Tc(N)(PNP{sub 3})DTCZ]{sup +} and [{sup 99m}Tc(N)(PNP{sub 5})DTCZ]{sup +} complexes showed that they selectively localize in the myocardium of rats with a favourable heart-to-lung and heart-to-liver uptake ratios. In particular, the heart-to-lung and heart-to-liver uptake ratios dramatically

  6. High performance nano-composite technology development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D. [KAERI, Taejon (Korea, Republic of); Kim, E. K.; Jung, S. Y.; Ryu, H. J. [KRICT, Taejon (Korea, Republic of); Hwang, S. S.; Kim, J. K.; Hong, S. M. [KIST, Taejon (Korea, Republic of); Chea, Y. B. [KIGAM, Taejon (Korea, Republic of); Choi, C. H.; Kim, S. D. [ATS, Taejon (Korea, Republic of); Cho, B. G.; Lee, S. H. [HGREC, Taejon (Korea, Republic of)

    1999-06-15

    The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

  7. Quasiparticle States at a d-Wave Vortex Core in High-Tc Superconductors: Induction of Local Spin Density Wave Order

    OpenAIRE

    Zhu, Jian-Xin; Ting, C. S.

    2001-01-01

    The local density of states (LDOS) at one of the vortex lattice cores in a high Tc superconductor is studied by using a self-consistent mean field theory including interactions for both antiferromagnetism (AF) and d-wave superconductivity (DSC). The parameters are chosen in such a way that in an optimally doped sample the AF order is completely suppressed while DSC prevails. In the mixed state, we show that the local AF-like SDW order appears near the vortex core and acts as an effective loca...

  8. New high- Tc 2-2-3 type superconductor Y 2Ba 1.5Ca 0.5Cu 3O 8+δ

    Science.gov (United States)

    Kulkarni, R. G.; Baldha, G. J.; Mohan, H.; Jotania, R. B.; Joshi, H. H.; Skumryev, V.; Rao, K. V.

    1990-02-01

    We have prepared and identified as a single-phase the new high- Tc 2-2-3 type superconductor Y 2Ba 1.5Ca 0.5Cu 3O 8+δ by resistance and a.c.-susceptibility measurements. The resistive superconducting onset occurs at 82 K and "zero resistance" at 78 K. Diamagnetism and Meissner effect sets in at low fields and magnetic superconducting onset starts at 82 K. The systematic investigation of the real and imaginary components of a.c.-susceptibility reveals that the magnetic behavior is that of a granular type superconductor.

  9. The Role of Compositional Tuning of the Distributed Exchange on Magnetocaloric Properties of High-Entropy Alloys

    Science.gov (United States)

    Perrin, Alice; Sorescu, Monica; Burton, Mari-Therese; Laughlin, David E.; McHenry, Michael

    2017-11-01

    This paper explores the FeCoNiCuMn high-entropy alloy system, where small departures from equiatomic composition have yielded technologically interesting 300-K Curie temperatures (Tc), making them promising for magnetocaloric applications. We also demonstrate that the small deviations from equiatomic compositions do not affect the structural stability of our single-phase fcc-based solid solutions. Room-temperature Mössbauer spectroscopy measurements provide evidence for the distributed exchange interactions (J_{ex}) occurring between the magnetic elements, which contribute to a broadened magnetocaloric effect observed for these alloys. The average hyperfine field observed in the Mössbauer spectra decreases as the Tc of the alloys decrease, confirming direct current magnetic measurements. Multiple peaks in the hyperfine field distribution are interpreted considering pairwise ferromagnetic or antiferromagnetic J_{ex} between all elements except the Cu diluent as contributing to overall magnetic exchange in the alloy.

  10. High Performance Graphene Oxide Based Rubber Composites

    Science.gov (United States)

    Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

    2013-08-01

    In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.

  11. High Performance Graphene Oxide Based Rubber Composites

    Science.gov (United States)

    Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

    2013-01-01

    In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications. PMID:23974435

  12. Laminar composite structures for high power actuators

    Science.gov (United States)

    Hobosyan, M. A.; Martinez, P. M.; Zakhidov, A. A.; Haines, C. S.; Baughman, R. H.; Martirosyan, K. S.

    2017-05-01

    Twisted laminar composite structures for high power and large-stroke actuators based on coiled Multi Wall Carbon Nanotube (MWNT) composite yarns were crafted by integrating high-density Nanoenergetic Gas Generators (NGGs) into carbon nanotube sheets. The linear actuation force, resulting from the pneumatic force caused by expanding gases confined within the pores of laminar structures and twisted carbon nanotube yarns, can be further amplified by increasing NGG loading and yarns twist density, as well as selecting NGG compositions with high energy density and large-volume gas generation. Moreover, the actuation force and power can be tuned by the surrounding environment, such as to increase the actuation by combustion in ambient air. A single 300-μm-diameter integrated MWNT/NGG coiled yarn produced 0.7 MPa stress and a contractile specific work power of up to 4.7 kW/kg, while combustion front propagated along the yarn at a velocity up to 10 m/s. Such powerful yarn actuators can also be operated in a vacuum, enabling their potential use for deploying heavy loads in outer space, such as to unfold solar panels and solar sails.

  13. Tc Generator Development: Up-to-Date Tc Recovery Technologies for Increasing the Effectiveness of Mo Utilisation

    Directory of Open Access Journals (Sweden)

    Van So Le

    2014-01-01

    Full Text Available A review on the Mo sources available today and on the Tc generators developed up to date for increasing the effectiveness of Mo utilisation is performed in the format of detailed description of the features and technical performance of the technological groups of the Mo production and Tc recovery. The latest results of the endeavour in this field are also surveyed in regard of the technical solution for overcoming the shortage of Mo supply. The technological topics are grouped and discussed in a way to reflect the similarity in the technological process of each group. The following groups are included in this review which are high specific activity Mo: the current issues of production, the efforts of more effective utilisation, and the high specific activity Mo-based Tc generator and Tc concentration units; low specific activity Mo: the Mo production based on neutron capture and accelerators and the direct production of Tc and the methods of increasing the specific activity of Mo using Szilard-Chalmers reaction and high electric power isotopic separator; up-to-date technologies of Tc recovery from low specific activity Mo: the solvent extraction-based Tc generator, the sublimation methods for Mo/Tc separation, the electrochemical method for Tc recovery, and the column chromatographic methods for Tc recovery. Besides the traditional Tc-generator systems, the integrated Tc generator systems (Tc generator column combined with postelution purification/concentration unit are discussed with the format of process diagram and picture of real generator systems. These systems are the technetium selective sorbent column-based generators, the high Mo-loading capacity column-based integrated Tc generator systems which include the saline-eluted generator systems, and the nonsaline aqueous and organic solvent eluent-eluted generator systems using high Mo-loading capacity molybdategel and recently developed sorbent columns. Tc concentration methods used in the

  14. High School Economic Composition and College Persistence

    Science.gov (United States)

    Tienda, Marta

    2013-01-01

    Using a longitudinal sample of Texas high school seniors of 2002 who enrolled in college within the calendar year of high school graduation, we examine variation in college persistence according to the economic composition of their high schools, which serves as a proxy for unmeasured high school attributes that are conductive to postsecondary success. Students who graduated from affluent high schools have the highest persistence rates and those who attended poor high schools have the lowest rates. Multivariate analyses indicate that the advantages in persistence and on-time graduation from four-year colleges enjoyed by graduates of affluent high schools cannot be fully explained by high school college orientation and academic rigor, family background, pre-college academic preparedness or the institutional characteristics. High school college orientation, family background and pre-college academic preparation largely explain why graduates from affluent high schools who first enroll in two-year colleges have higher transfer rates to four-year institutions; however these factors and college characteristics do not explain the lower transfer rates for students from poor high schools. The conclusion discusses the implications of the empirical findings in light of several recent studies that call attention to the policy importance of high schools as a lever to improve persistence and completion rates via better institutional matches. PMID:23459198

  15. Direct 99m Tc labeling of Herceptin (trastuzumab) by 99m Tc(I) tricarbonyl ion.

    Science.gov (United States)

    Chen, Wan-Jou; Yen, Chao-Liang; Lo, Su-Tang; Chen, Kuo-Ting; Lo, Jem-Mau

    2008-03-01

    By simply incubating Herceptin (trastuzumab) with [99m Tc(CO)3(OH2)3]+ ion in saline, a significant yield of 99m Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which 99m Tc(I) tricarbonyl ion can be strongly bound. For practical 99m Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, alpha-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [99m Tc(CO)3(OH2)3]+. Retention of bioactivity of the 99m Tc(I)-labeled trastuzumab was validated using a cell binding test.

  16. Highly Conducting Graphite Epoxy Composite Demonstrated

    Science.gov (United States)

    Gaier, James R.

    1999-01-01

    Weight savings as high as 80 percent could be achieved if graphite polymer composites could replace aluminum in structures such as electromagnetic interference shielding covers and grounding planes. This could result in significant cost savings, especially for the mobile electronics found in spacecraft, aircraft, automobiles, and hand-held consumer electronics. However, such composites had not yet been fabricated with conductivity sufficient to enable these applications. To address this lack, a partnership of the NASA Lewis Research Center, Manchester College, and Applied Sciences, Inc., fabricated nonmetallic composites with unprecedented electrical conductivity. For these composites, heat-treated, vapor-grown graphite fibers were selected which have a resistivity of about 80 mW-cm, more than 20 times more conductive than typical carbon fibers. These fibers were then intercalated with iodine bromide (IBr). Intercalation is the insertion of guest atoms or molecules between the carbon planes of the graphite fibers. Since the carbon planes are not highly distorted in the process, intercalation has little effect on mechanical and thermal properties. Intercalation does, however, lower the carbon fiber resistivity to less than 10 mW-cm, which is comparable to that of metal fibers. Scaleup of the reaction was required since the initial intercalation experiments would be carried out on 20-mg quantities of fibers, and tens of grams of intercalated fibers would be needed to fabricate even small demonstration composites. The reaction was first optimized through a time and temperature study that yielded fibers with a resistivity of 8.7 2 mW-cm when exposed to IBr vapor at 114 C for 24 hours. Stability studies indicated that the intercalated fibers rapidly lost their conductivity when exposed to temperatures as low as 40 C in air. They were not, however, susceptible to degradation by water vapor in the manner of most graphite intercalation compounds. The 1000-fold scaleup

  17. Development of Tc(IV)-Incorporated Fe Minerals to Enhance 99Tc Retention in Glass Waste Form

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Luksic, Steven A.; Wang, Guohui; Kim, Dong-Sang; Schweiger, Michael J.; Hrma, Pavel R.; Kruger, Albert A.

    2015-03-17

    Iron minerals have been considered to be good hosts for Tc immobilization because the Tc(IV) ion substitutes for Fe(III) in the crystal structure of the Fe oxide due to similarities in (1) cation size [Tc(IV) = 78.5 pm ; Fe(III) = 69 or 78.5 pm], (2) metal-oxygen interatomic distance (Tc—O = 0.199 nm, Fe—O = 0.203 nm), (3) number of coordinating oxygen atoms (both 6-fold coordinated), and (4) the redox potential (Eh=ca. +20 mV at pH = 7) for a redox couple between Tc(VII)/Tc(IV) and Fe(III)/Fe(II). Magnetite, maghemite, and trevorite are iron oxide minerals and all belong to spinel mineral group. Laboratory testing shows that Tc can be removed from aqueous waste solutions by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation with iron oxide minerals during recrystallization of Fe(OH)2(s) used as an initial solid precursor. X-ray absorption near edge structure (XANES) spectroscopy confirmed that Tc was in the +4 oxidation state in final Tc-Fe minerals. The Tc-incorporated Fe minerals were also tested for Tc retention in glass melts at different temperatures between 600 – 1,000 oC in a furnace. After being cooled in air, the solid glass specimens collected at different temperatures were analyzed for Tc oxidation state using XANES and Tc retention using liquid scintillation counting (LSC). Even though Tc(IV) started to reoxidize at 600 oC, Tc retention in the final glass specimen prepared with Tc-incorporated Fe mineral even at high temperatures was at least two times higher than glass prepared with KTcO4 salt. Higher Tc retention in glass is considered to result from limited and delayed Tc volatilization process due to Fe mineral encapsulation for Tc. Therefore, the results showing the presence of Tc(IV) in the Fe mineral structure indicate strong possibility to enhance Tc retention in borosilicate glass as well as to reduce the remediation costs at the Hanford Site.

  18. Tuning effective interactions in high-Tc cuprates via apical oxygen atoms: New realization from the first-principles Wannier function approach

    Science.gov (United States)

    Yin, Weiguo; Ku, Wei

    2007-03-01

    Based on a novel first-principles Wannier function approach, the low-energy effective Hamiltonian for high-Tc cuprates is derived. The apical oxygen atoms are found to significantly modify the mobility and distribution of the Zhang-Rice singlets in the CuO2 plane, by tuning the effective hopping parameters t^' and t^'', and local chemical potential, μeff. Most remarkably, Veff, an additional effective repulsion (de- pairing) between neighboring doped holes, is found to be significantly tuned by a ``vacuum fluctuation'' mechanism inherited from the correlated multiband nature of the cuprates. Our results identify the apical oxygen states as the main material dependence of these systems and provide a microscopic avenue to the understanding of recent spectroscopic imaging STM data [K. McElroy et al., Science 309, 1048 (2005)].

  19. High-Tc superconducting EuBa2Cu3O(y) thin films on MgO and YAlO3 for coplanar devices

    Science.gov (United States)

    Asano, H.; Satoh, M.; Konaka, T.

    1993-03-01

    The authors have studied the microwave properties of high-Tc superconducting EuBa2Cu3Oy (EBCO) films on MgO and YAlO3 substrates with low dielectric constants and a low loss tangent. Measurements of surface resistance Rs at 50 GHz in a cavity show that EBCO films exhibit low Rs values (77 K) of 2-10 micro-ohm. A microstructural study using transmission electron microscopy showed that crystal defects related to the in-plane misorientation are observed for films with higher Rs values. The Rs values of the patterned films were measured in a coplanar transmission line resonator. A typical value for patterned films was 28 micro-ohms at 4 GHz and 28 K.

  20. High-Tc copper oxide superconductors and related novel materials dedicated to prof K. A. Müller on the occasion of his 90th birthday

    CERN Document Server

    Keller, Hugo; Bianconi, Antonio

    2017-01-01

    Authored by many of the world's leading experts on high-Tc superconductivity, this volume presents a panorama of ongoing research in the field, as well as insights into related multifunctional materials. The contributions cover many different and complementary aspects of the physics and materials challenges, with an emphasis on superconducting materials that have emerged since the discovery of the cuprate superconductors, for example pnictides, MgB2, H2S and other hydrides. Special attention is also paid to interface superconductivity. In addition to superconductors, the volume also addresses materials related to polar and multifunctional ground states, another class of materials that owes its discovery to Prof. Müller's ground-breaking research on SrTiO3.

  1. Fracture behavior of an inclined crack interacting with a circular inclusion in a high-TC superconductor under an electromagnetic force

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2015-11-01

    Full Text Available A simple model is proposed to investigate the interaction problem for a circular nonsuperconducting inclusion embedded in a high-TC superconducting matrix which contains an inclined crack, oriented at an arbitrary angle from the direction of the critical currents. The electromagnetic behavior is described by the critical state, the original Bean model. The perturbation brought upon by the circular inclusion and the crack on the critical current density is assumed to be negligible and not considered in this model. The distribution dislocation technology is applied to formulate the current problem. The stress intensity factors (SIFs are obtained by solving the formulated singular integral equations. The effects of the crack angle, the elastic modulus, the inclusion-crack distance and the inclusion-crack size on the stress intensity factors are discussed in detail.

  2. Determination of Tc-99 in radioactive wastes; Determinacion de Tc-99 en desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rivera S, A. A.

    2015-07-01

    Tc-99 is a fission product and one of the most important radionuclides from the view point of safety assessment for the disposal of radioactive waste because of its long half-life (2.1 x 10{sup 5} years) and high mobility in soil-water systems, if this is released into the environment in significant quantities can concentrate on plants and animals. Tc-99 is a pure beta emitter with a maximum energy of 292 KeV, so their quantification imposes destructive methods to be analyzed by liquid scintillation. Therefore the quantification of Tc-99 in ion exchange resins requires of the mineralization of these and separation of Tc-99 of other radioisotopes present in the resin. Therefore the object of this thesis is to develop a quantification method of Tc-99 content in spent exchange resins. So in order to track the behavior of technetium during digestion exchange resins and radiochemical separation, given its high volatility, in this work the {sup 99m}Tc is used. To determine the degree of mineralization of the resins, an analysis was performed by chromatography. Subsequently the method used to determine the percentage of {sup 99m}Tc aerosolized during mineralization of resin is described. After the method for the radiochemical separation of {sup 99m}Tc is presented by liquid-liquid extraction using crown ether as extractant; for this testing was performed by varying the molarity of the extractant, the ratio of solvent extractant, type of digestion of the resin and the presence of Sr-85, in order to study the behavior of {sup 99m}Tc in the presence of this radioisotope. Finally, a track beta spectra of a sample of {sup 99m}Tc eluted from a generator {sup 99}Mo/{sup 99m}Tc function of time was performed. (Author)

  3. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  4. Correlation between fabrication factor and superconducting properties of the Tl-and-Bi-based high-Tc superconductor

    Science.gov (United States)

    Maki, Naoki; Okada, Michiya; Doi, Toshiya J.; Kanai, Tsuneyuki; Sato, Junichi; Higashiyama, Kazutoshi

    1995-01-01

    Large critical current densities (J(sub c)) were obtained in c axis oriented Tl-1 223/Ag composite tapes fabricated by spraying methods without a vacuum. Transport measurements at 77K under a zero field indicated a J(sub c) of 9 x 10(exp 4) A/sq cm and 7 x 10(exp 3) A/sq cm at 1T for the tapes fabricated by spray pyrolysis. The novel GPM method was also applied for Bi-2212/Ag PIT composite wire, and found to be very effective for improving the distribution of voids, which caused from the melt-solidifying process. The GPM showed a marked effect for obtaining homogeneous long wire. A 1 T class coil was successfully fabricated with monocore wire.

  5. [SLCO1B1c. 521T>C gene polymorphisms are associated with high-dose methotrexate pharmacokinetics and clinical outcome of pediatric acute lymphoblastic leukemia].

    Science.gov (United States)

    Zhang, Huanian; He, Xuelian; Li, Jianxin; Wang, Yang; Wang, Cheng; Chen, Yujun; Niu, Changhe; Gao, Ping

    2014-10-01

    To provide guidance for the high-dose methotrexate (HD-MTX) treatment of pediatric acute lymphoblastic leukemia (ALL), and to understand the impact of SLCO1B1c.521T>C (rs4149056) variant on methotrexate (MTX) pharmacokinetics and clinical outcome in children with ALL. Eighty-two children with ALL in Division of Hematology of Wuhan Children's Hospital from January 2008 to February 2013 were enrolled. All patients were genotyped for rs4149056 single nucleotide polymorphism (SNP) into wild-type group (TT genotype) and variant group (TC/CC genotype). According to the ALL-BFM 2000 protocol, all patients received intravenous infusion of MTX every ten days at 3 to 5 g/m(2). Leucovorin rescue was performed after 36 hours of the MTX administration and its dose was adjusted according to the MTX plasma concentration at 48 hours. The concentrations of MTX and its metabolite at 24, 48 and 72 h were determined by high performance liquid chromatography with solid phase extraction. Population pharmacokinetic parameters were estimated by the NLME software. The pharmacokinetics, toxicity and leucovorin rescue was compared. The relapse rate within 5 years and event-free survival were followed up. Eighty-two pediatric patients were classified into two groups: variant group including 20 TC genotype carriers and one CC genotype carrier, wild-type group included 61 patients with TT genotype. Compared with wild-type group, plasma concentration of MTX at 48 and 72 h increased significantly [48 h: (1.00±1.41) vs.(0.34±0.17) µmol/L, t=2.131, P=0.046; 72 h: (0.31±0.26) vs.(0.08±0.04) µmol/L; t=3.995, P=0.001]. Area under the concentration time curve (AUC48-∝) of MTX significantly increased in variant group [(23.18±19.91) vs.(5.66±2.01) h·µmol/L] (t=4.025, P=0.001). Time above the MTX safety threshold (TC>0.1 µmol/L) increased significantly in variant group [(95.3±22.0) vs.(67.1±7.5) h, t=5.880, Prs4149056 C allele suffered from a higher frequency of serious adverse effect

  6. Synthesis and Characterization of Tc(I) Carbonyl Nitrosyl Species Relevant to the Hanford Tank Waste: FY 2016 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Martin, Thibaut J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Nathalie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-24

    Among long-lived radioactive constituents in the Hanford tank waste, Tc presents a unique challenge in that it exists predominantly in the liquid phase, generally in the anionic form of pertechnetate, TcO4-, which is highly volatile at low-activity waste (LAW) vitrification melter temperatures and mobile in the Hanford site’s subsurface environment. The complex behavior of Tc under storage, treatment, and immobilization conditions significantly affects its management options, which to-date remain uncertain. In strongly alkaline environments, Tc exists as pertechnetate, TcO4- (oxidation state +7), and in the reduced forms (oxidation state < +7) collectively known as non-pertechnetate species. Pertechnetate is a well-characterized, anionic Tc species that can be removed from LAW by anion exchange or solvent extraction methods. There is no definitive information on the origin of the non-pertechnetate Tc species, nor is there a comprehensive description of their composition and behavior. It has been recently proposed that the non-pertechnetate species can comprise Tc(I) metal center and carbonyl or mixed carbonyl nitrosyl ligands stabilizing low-valent Tc. Recent work by our group has significantly expanded this previous work, generating a series of Tc(I) carbonyl compounds and demonstrating that they can be generated from reduction of TcO4- in the simulated Hanford tank waste in presence of CO at elevated temperature (Levitskaia et al. 2014). These results are consistent with the previous proposal that [Tc(CO)3]+ species can be present in the Hanford tank waste and suggest that the low Tc(I) oxidation state is stabilized by the π-accepting ability of the CO ligands. The continuation work has been initiated to develop model Tc carbonyl nitrosyl compounds and investigate their potential presence in the Hanford tank wastes. This report summarizes our to-date results.

  7. Highly efficient solid phase supported radiosynthesis of [11 C]PiB using tC18 cartridge as a "3-in-1" production entity.

    Science.gov (United States)

    Boudjemeline, Mehdi; Hopewell, Robert; Rochon, Pierre-Luc; Jolly, Dean; Hammami, Iness; Villeneuve, Sylvia; Kostikov, Alexey

    2017-10-05

    Pittsburgh compound B ([11 C]PiB) is the gold standard positron emission tomography (PET) tracer for the in vivo imaging of amyloid plaques. Currently, it is synthesized by either solution chemistry or using a "dry loop" approach followed by HPLC purification within 30 minutes starting from [11 C]CO2 . Here, we report a novel, highly efficient solid phase supported carbon-11 radiolabeling procedure using commercially available disposable tC18 cartridge as a "3-in-1" entity: reactor, purifier, and solvent replacement system. [11 C]PiB is synthesized by passing gaseous [11 C]CH3 OTf through a tC18 cartridge preloaded with a solution of precursor. Successive elution with aqueous ethanol solutions allows for nearly quantitative separation of the reaction mixture to provide chemically and radiochemically pure PET tracer. [11 C]PiB suitable for human injection is produced within 10 minutes starting from [11 C]CH3 OTf (20 min from [11 C]CO2 ) in 22% isolated yield not corrected for decay and molar activity of 190 GBq/μmol using 0.2 mg of precursor. This technique reduces the amount of precursor and other supplies, avoids use of preparative HPLC and toxic solvents, and decreases the time between consecutive production batches. Solid phase supported technique can facilitate [11 C]PiB production compliant with Good Manufacturing Practice (GMP) and improve synthesis reliability. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Possible association of ABCB1:c.3435T>C polymorphism with high-density-lipoprotein-cholesterol response to statin treatment - a pilot study.

    Directory of Open Access Journals (Sweden)

    Anna Sałacka

    2014-08-01

    Full Text Available The gene product ABCB1 (formerly MDR1 or P-glycoprotein is hypothesized to be involved in cholesterol cellular trafficking, redistribution and intestinal re-absorption. Carriers of the ABCB1:3435T allele have previously been associated with decreases in ABCB1 mRNA and protein concentrations and have been correlated with changes in serum lipid concentrations. The aim of this study was to investigate possible association between the ABCB1:3435T>C polymorphism and changes in lipids in patients following statin treatment. Outpatients (n=130 were examined: 43 men (33%, 87 women (67%: treated with atorvastatin or simvastatin (all patients with equivalent dose of 20 or 40 mg/d simvastatin. Blood was taken for ABCB1:3435T>C genotyping, and before and after statin treatment for lipid concentration determination (total cholesterol, high-density-lipoprotein-cholesterol (HDL-C, triglycerides. Change (Δ in lipid parameters, calculated as differences between measurements before and after treatment, were analyzed with multiple regression adjustments: gender, diabetes, age, body mass index, equivalent statin dose, length of treatment. Univariate and multivariate analyses showed significant differences in ΔHDL-C (univariate p=0.029; multivariate p=0.036 and %ΔHDL-C (univariate p=0.021; multivariate p=0.023 between patients with TT (-0.05 ± 0.13 g/l; -6.8% ± 20%; respectively and CC+CT genotypes (0.004 ± 0.15 g/l; 4.1 ± 26%; respectively. Reduction of HDL-C in homozygous ABCB1:3435TT patients suggests this genotype could be associated with a reduction in the benefits of statin treatment.

  9. Efficient preparation of {sup 99m}Tc(III) '4+1' mixed-ligand complexes for peptide labeling with high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Kunstler, Jens-Uwe [Biotectid GmbH, Deutscher Platz 5c, 04103 Leipzig (Germany); Seidel, Gesine [Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany); Pietzsch, Hans-Jurgen, E-mail: h.j.pietzsch@fzd.d [Institute of Radiopharmacy, Forschungszentrum Dresden-Rossendorf, P.O. Box 510 119, 01314 Dresden (Germany)

    2010-09-15

    An improved labeling procedure for peptides attached to organometallic {sup 99m}Tc(III) '4+1' mixed-ligand complexes in which the radiometal is coordinated by a tripodal tetradentate chelator 2,2',2''-nitrilotriethanethiol (NS{sub 3}) and a monodentate isocyanide ligand is presented. The labeling procedure was evaluated by the synthesis of [{sup 99m}Tc(NS{sub 3})(L2-RGD)]. The containing radiopharmaceutically interesting RGD-peptide cyclo[Arg-Gly-Asp-D-Tyr-Lys] was modified with 4-isocyanobutanoic acid (L2) as linker conjugated to N{sup 6}-Lys to get the monodentate ligand L2-RGD. The structural identity of the {sup 99m}Tc-conjugate was confirmed by comparison to a Re reference compound. The Tc- and Re-conjugates had matching retention times under identical HPLC conditions. The {sup 99m}Tc-labeling was performed in a novel one-step procedure using the eluate of a {sup 99}Mo/{sup 99m}Tc generator, NS{sub 3}, the isocyanide modified peptide, SnCl{sub 2}, Na{sub 2}EDTA, mannitol and ascorbic acid in the reaction mixture. Using optimized reagents it is possible to label 50 nmol peptide with {sup 99m}Tc within 60 min at room temperature with a radiochemical yield higher than 95% and a specific activity of {approx}20 GBq/{mu}mol.

  10. Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Peng Dengfeng [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Wang Xusheng; Yao Xi [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xu Chaonan [National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Lin Jian; Sun Tiantuo [College of Material Science and Engineering, Tongji University, 4800 Cao' an Highway, Shanghai 201804 (China)

    2012-05-15

    Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

  11. TC4 AMPR BRIGHTNESS TEMPERATURE (TB) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The TC4 AMPR Brightness Temperature (TB) dataset consists of brightness temperature data from July 19, 2007 through August 8, 2007. The Tropical Composition, Cloud...

  12. Characterizing isotopic compositions of TC-C, NO3--N, and NH4+-N in PM2.5in South Korea: Impact of China's winter heating.

    Science.gov (United States)

    Park, Yu-Mi; Park, Kwang-Su; Kim, Hyuk; Yu, Seok-Min; Noh, Seam; Kim, Min-Seob; Kim, Jee-Young; Ahn, Joon-Young; Lee, Min-do; Seok, Kwang-Seol; Kim, Young-Hee

    2018-02-01

    The origin of PM 2.5 has long been the subject of debate and stable isotopic tools have been applied to decipher. In this study, weekly PM 2.5 samples were simultaneously collected at an urban (Seoul) and rural (Baengnyeong Island) site in Korea from January 2014 through February 2016. The seasonal variation of isotopic species showed significant seasonal differences with sinusoidal variation. The isotopic results implied that isotope species from Baengnyeong were mostly originated from coal combustion during China's winter heating seasons, whereas in summer, the isotopic patterns observed that were more likely to be from marine. In Seoul, coal combustion related isotopic patterns increased during China's winter heating period while vehicle related isotopic patterns were dominated whole seasons by default. Therefore, aerosol formation was originated from long-range transported coal combustion-related NO x by vehicle-related NH 3 in Seoul. δN-NH 4 + in Seoul showed highly enriched 15 N compositions in all seasons, indicating that NH 3 from vehicle emission is the important source of NH 4 + in PM 2.5 in Seoul. In addition, Baengnyeong should be consistently considered as a key region for observing the changes of isotopic features depend on the contribution of individual emissions to the atmospheric as a result of the reduction of coal consumption in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Establishment of an experimental human lung adenocarcinoma cell line SPC-A-1BM with high bone metastases potency by {sup 99m}Tc-MDP bone scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Yang Shunfang [Department of Nuclear Medicine, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China)], E-mail: yzyg@sh163.net; Dong Qianggang [Laboratory of Mol-diagnosis, Shanghai Cancer Institute of Shanghai Jiaotong University, Shanghai 200032 (China); Yao Ming [Laboratory of Pathology, Shanghai Cancer Institute of Shanghai Jiaotong University, Shanghai 200032 (China); Shi Meiping [Department of Pathology, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Ye Jianding [Department of Radiology, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Zhao Langxiang [Department of Pathology, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Su Jianzhong; Gu Weiyong [Shanghai Thoracic Tumor Institute, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Xie Wenhui [Department of Nuclear Medicine, Shanghai Chest Hospital of Shanghai Jiaotong University, Shanghai 200030 (China); Wang Kankan; Du Yanzhi [State Key Laboratory of Medical Genomics, Ruijin Hospital of Shanghai Jiaotong University, Shanghai 200025 (China); Li Yao [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433 (China); Huang Yan [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433 (China)], E-mail: huangyan@fudan.edu.cn

    2009-04-15

    Background: Bone metastasis is one of the most common clinical phenomena of late stage lung cancer. A major impediment to understanding the pathogenesis of bone metastasis has been the lack of an appropriate animal and cell model. This study aims to establish human lung adenocarcinoma cell line with highly bone metastases potency with {sup 99m}Tc-MDP bone scintigraphy. Methods: The human lung adenocarcinoma cancer cells SPC-A-1 were injected into the left cardiac ventricle of NIH-Beige-Nude-XID (NIH-BNX) immunodeficient mice. The metastatic lesions of tumor-bearing mice were imaged with {sup 99m}Tc-MDP bone scintigraphy on a Siemens multi-single photon emission computed tomography. Pinhole images were acquired on a GZ-B conventional gamma camera with a self-designed pinhole collimator. The mice with bone metastasis were sacrificed under deep anesthesia, and the lesions were resected. Bone metastatic cancer cells in the resected lesions were subjected for culture and then reinoculated into the NIH-BNX mice through left cardiac ventricle. The process was repeated for eight cycles to obtain a novel cell subline SPC-A-1BM. Real-time polymerase chain reaction (PCR) was used to compare the gene expression differences in the parental and SPC-A-1BM cells. Results: The bone metastasis sites were successfully revealed by bone scintigraphy. The established bone metastasis cell line SPC-A-1BM had a high potential to metastasize in bone, including mandible, humerus, thoracic vertebra, lumbar, femur, patella, ilium and cartilage rib. The expression level of vascular endothelial growth factor gene family, Bcl-2 and cell adhesion-related genes ECM1, ESM1, AF1Q, SERPINE2 and FN1 were examined. Gene expression difference was found between parental and bone-seeking metastasis cell SPC-A-1BM, which indicates SPC-A-1BM has metastatic capacity vs. its parental cells. Conclusion: SPC-A-1BM is a bone-seeking metastasis human lung adenocarcinoma cell line. Bone scintigraphy may be used as

  14. Experimental Investigation on Thermoresistance between AlN, Bi-2223 and OFHC in High Tc- Direct Cooling Technology

    Science.gov (United States)

    Wang, H. L.; Rao, R. S.; Wang, J.

    2014-12-01

    In the development of high temperature superconducting (HTS) direct cooling technology, the high electric insulation high heat conducting AlN has become one of the important components. The thermal contact resistance between AlN, Bi-2223 and OFHC is investigated by experiment with a G-M cryocooler as the source of cooling. The heat conductivity of AlN is measured between 29 and 160 K temperatures. When the temperature on the interface layer side of Bi-2223 is 55 K, under the action of the contact pressure of 0.5469 MPa, the thermal contact resistance between AlN and Bi-2223 is 38.86 times to the thermal conduction resistance of a 10 mm thick AlN pad. Baced on micro-nanocryogenics, it is proposed that the thermal contact resistance is one of the crucial techniques to be attacked in HTS direct cooling technology.

  15. High-Tc superconductivity in ultrathin Bi2Sr2CaCu2O(8+x) down to half-unit-cell thickness by protection with graphene.

    Science.gov (United States)

    Jiang, Da; Hu, Tao; You, Lixing; Li, Qiao; Li, Ang; Wang, Haomin; Mu, Gang; Chen, Zhiying; Zhang, Haoran; Yu, Guanghui; Zhu, Jie; Sun, Qiujuan; Lin, Chengtian; Xiao, Hong; Xie, Xiaoming; Jiang, Mianheng

    2014-12-08

    High-Tc superconductors confined to two dimension exhibit novel physical phenomena, such as superconductor-insulator transition. In the Bi2Sr2CaCu2O(8+x) (Bi2212) model system, despite extensive studies, the intrinsic superconducting properties at the thinness limit have been difficult to determine. Here, we report a method to fabricate high quality single-crystal Bi2212 films down to half-unit-cell thickness in the form of graphene/Bi2212 van der Waals heterostructure, in which sharp superconducting transitions are observed. The heterostructure also exhibits a nonlinear current-voltage characteristic due to the Dirac nature of the graphene band structure. More interestingly, although the critical temperature remains essentially the same with reduced thickness of Bi2212, the slope of the normal state T-linear resistivity varies by a factor of 4-5, and the sheet resistance increases by three orders of magnitude, indicating a surprising decoupling of the normal state resistance and superconductivity. The developed technique is versatile, applicable to investigate other two-dimensional (2D) superconducting materials.

  16. High performance carbon-carbon composites

    Indian Academy of Sciences (India)

    These composites are made of fibres in various directions and carbonaceous polymers and hydrocarbons as matrix precursors. Their density and properties depend on the type and volume fraction of reinforcement, matrix precursor used and end heat treatment temperature. Composites made with thermosetting resins as ...

  17. Effects of magnetic field on the cuprate high-Tc superconductor La2-xSrxCuO4

    DEFF Research Database (Denmark)

    Lake, B.; Aeppli, G.; Christensen, N.B.

    2004-01-01

    This article discusses neutron scattering measurements on the cuprate, high transition temperature superconductor La2-xSrxCuO4 (LSCO) in an applied magnetic field. LSCO is a type-II superconductor and magnetic flux can penetrate the material via the formation of vorticies. Phase coherent...

  18. CTLA-4 (CD152) enhances the Tc17 differentiation program.

    Science.gov (United States)

    Pick, Jonas; Arra, Aditya; Lingel, Holger; Hegel, J Kolja; Huber, Magdalena; Nishanth, Gopala; Jorch, Gerhard; Fischer, Klaus-Dieter; Schlüter, Dirk; Tedford, Kerry; Brunner-Weinzierl, Monika C

    2014-07-01

    Although CD8(+) T cells that produce IL-17 (Tc17 cells) have been linked to host defense, Tc17 cells show reduced cytotoxic activity, which is the characteristic function of CD8(+) T cells. Here, we show that CTLA-4 enhances the frequency of IL-17 in CD8(+) T cells, indicating that CTLA-4 (CD152) specifically promotes Tc17 differentiation. Simultaneous stimulation of CTLA-4(+/+) and CTLA-4(-/-) T cells in cocultures and agonistic CTLA-4 stimulation unambiguously revealed a cell-intrinsic mechanism for IL-17 control by CTLA-4. The quality of CTLA-4-induced Tc17 cells was tested in vivo, utilizing infection with the facultative intracellular bacterium Listeria monocytogenes (LM). Unlike CTLA-4(+/+) Tc17 cells, CTLA-4(-/-) were nearly as efficient as Tc1 CTLA-4(+/+) cells in LM clearance. Additionally, adoptively transferred CTLA-4(-/-) Tc17 cells expressed granzyme B after rechallenge, and produced Tc1 cytokines such as IFN-γ and TNF-α, which strongly correlate with bacterial clearance. CTLA-4(+/+) Tc17 cells demonstrated a high-quality Tc17 differentiation program ex vivo, which was also evident in isolated IL-17-secreting Tc17 cells, with CTLA-4-mediated enhanced upregulation of Tc17-related molecules such as IL-17A, RORγt, and IRF-4. Our results show that CTLA-4 promotes Tc17 differentiation that results in robust Tc17 responses. Its inactivation might therefore represent a central therapeutic target to enhance clearance of infection. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Non-destructive Testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    Science.gov (United States)

    Lu, D. F.; Fan, Chang-Xin; Ruan, J. Z.; Han, S. G.; Wong, K. W.; Sun, G. F.

    1995-01-01

    A SQUID is the most sensitive device to detect change in magnetic field. A nondestructive testing (NDT) device using high temperature SQUID's and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUID's. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  20. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, D.F.; Fan, C.; Ruan, J.Z. [Midwest Superconductivity Inc., Lawrence, KS (United States)] [and others

    1994-12-31

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  1. New high Tc multiferroics KBiFe2O5 with narrow band gap and promising photovoltaic effect

    Science.gov (United States)

    Zhang, Ganghua; Wu, Hui; Li, Guobao; Huang, Qingzhen; Yang, Chongyin; Huang, Fuqiang; Liao, Fuhui; Lin, Jianhua

    2013-01-01

    Intrinsic polarization of ferroelectrics (FE) helps separate photon-generated charge carriers thus enhances photovoltaic effects. However, traditional FE with transition-metal cations (M) of d0 electron in MO6 network typically has a band gap (Eg) exceeding 3.0 eV. Although a smaller Eg (2.6 eV) can be obtained in multiferroic BiFeO3, the value is still too high for optimal solar energy applications. Computational “materials genome” searches have predicted several exotic MO6 FE with Eg photoelectric activities. The high photovoltage (8.8 V) and photocurrent density (15 μA/cm2) were obtained, which is comparable to the reported BiFeO3. This finding may open a new avenue to discovering and designing optimal FE compounds for solar energy applications. PMID:23405279

  2. Fiber Based Optical Amplifier for High Energy Laser Pulses Final Report CRADA No. TC02100.0

    Energy Technology Data Exchange (ETDEWEB)

    Messerly, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cunningham, P. [Boeing Company, Springfield, VA (United States)

    2017-09-06

    This was a collaborative effort between Lawrence Livermore National Security, LLC (formerly The Regents of the University of California)/Lawrence Livermore National Laboratory (LLNL), and The Boeing Company to develop an optical fiber-based laser amplifier capable of producing and sustaining very high-energy, nanosecond-scale optical pulses. The overall technical objective of this CRADA was to research, design, and develop an optical fiber-based amplifier that would meet specific metrics.

  3. An explanation for the rise in Tc in the Tl- and Bi-based high temperature superconductors

    Science.gov (United States)

    Bose, S. M.; Longe, P.

    1991-01-01

    Using the plasmon exchange model for the high T(sub c) superconductor, it is shown that the T(sub c) rises with an increase in the number of CuO layers per unit cell, which is in agreement with recent observations in the Tl- and Bi-based compounds. The calculation also suggests that the sample will become superconducting in successive stages and that there is a saturation effect, i.e., that T(sub c) cannot be raised indefinitely by increasing the number of CuO layers.

  4. Simulation of Field Dependence of Critical Current Densities of Bulk High Tc Superconducting Materials regarding Thermally Activated Flux Motion

    Science.gov (United States)

    Santosh, M.; Naik, S. Pavan Kumar; Koblischka, M. R.

    2017-07-01

    In the upcoming generation, bulk high temperature superconductors (HTS) will play a crucial and a promising role in numerous industrial applications ranging from Maglev trains to magnetic resonance imaging, etc. Especially, the bulk HTS as permanent magnets are suitable due to the fact that they can trap magnetic fields being several orders of magnitude higher than those of the best hard ferromagnets. The bulk HTS LREBa2Cu3O7-δ (LREBCO or LRE-123, LRE: Y, Gd, etc.,) materials could obtain very powerful compact superconducting super-magnets, which can be operated at the cheaper liquid nitrogen temperature or below due to higher critical temperatures (i.e., ∼90 K). As a result, the new advanced technology can be utilized in a more attractive manner for a variety of technological and medical applications which have the capacity to revolutionize the field. An understanding of the magnetic field dependence of the critical current density (J c(H)) is important to develop better adapted materials. To achieve this goal, a variety of Jc (H) behaviours of bulk LREBCO samples were modelled regarding thermally activated flux motion. In essence, the Jc (H) curves follows a certain criterion where an exponential model is applied. However, to fit the complete Jc (H) curve of the LRE-123 samples an unique model is necessary to explain the behavior at low and high fields. The modelling of the various superconducting materials could be understood in terms of the pinning mechanisms.

  5. Enhancing electric-field control of ferromagnetism through nanoscale engineering of high-TcMnxGe1-xnanomesh.

    Science.gov (United States)

    Nie, Tianxiao; Tang, Jianshi; Kou, Xufeng; Gen, Yin; Lee, Shengwei; Zhu, Xiaodan; He, Qinglin; Chang, Li-Te; Murata, Koichi; Fan, Yabin; Wang, Kang L

    2016-10-20

    Voltage control of magnetism in ferromagnetic semiconductor has emerged as an appealing solution to significantly reduce the power dissipation and variability beyond current CMOS technology. However, it has been proven to be very challenging to achieve a candidate with high Curie temperature (T c ), controllable ferromagnetism and easy integration with current Si technology. Here we report the effective electric-field control of both ferromagnetism and magnetoresistance in unique Mn x Ge 1-x nanomeshes fabricated by nanosphere lithography, in which a T c above 400 K is demonstrated as a result of size/quantum confinement. Furthermore, by adjusting Mn doping concentration, extremely giant magnetoresistance is realized from ∼8,000% at 30 K to 75% at 300 K at 4 T, which arises from a geometrically enhanced magnetoresistance effect of the unique mesh structure. Our results may provide a paradigm for fundamentally understanding the high T c in ferromagnetic semiconductor nanostructure and realizing electric-field control of magnetoresistance for future spintronic applications.

  6. Practice of AC loss measurement in high Tc superconductor; Koon chodendo senzai no koryu sonshitsu sokutei jisshu

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, N.; Tsukamoto, O.; Ciszek, M. [Yokohama National Univ., Yokohama (Japan). Faculty of Engineering

    1999-06-07

    The cooperative research promotion center in the Yokohama National University was set up for a purpose to promote the co-operative research with civilian agencies, conduct and the co-operate technical education to engineers from civilian agencies and take the technical discussion and supply the academic information with civilian agencies. As one part of this work, the engineer training called as the high technology training was conducted. In this paper, the seminar on the alternate current loss measurement conducted in November 1998 was reported. This training was a 'high' technology training for an objective of engineers, 8 participants included engineers and graduate students in a major of superconductivity from makers, civilian institutes and universities as the superconducting specialists attended this lecture. In this training, lectures on the loss generating mechanism and the loss measurement principle and its practical use, manufacture of the measuring samples, measurement (the energization loss and magnetization loss), the report of measured results and examination and comments were carried out in order. In the manufacture of samples, participants carried out all soldering and pick-up coil rolls by handling sample tapes and sample holder parts. (NEDO)

  7. Planar defects, dislocations, and coherently scattering-size in GdBa2Cu3O7-x high-Tc thin films determined by high resolution X-ray diffraction

    DEFF Research Database (Denmark)

    Csiszár, Gábor; Li, Xiaofen; Zilahi, Gyula

    2013-01-01

    The frequency of planar defects, the average dislocation densities, and coherent domain size in epitaxial GdBa2Cu3O7-x high Tc thin films, with altering CuO2 and CuO planes, are measured by fitting full widths at half maximum values of 00l type reflections using a model function based on intensity...... distribution configurations in reciprocal space. The reduction of the dislocation density during oxygenation seems to be an unavoidable condition to obtain superconductivity in GdBa 2Cu3O7-x thin films. © 2013 American Institute of Physics....

  8. Wide applicability of high-Tc pairing originating from coexisting wide and incipient narrow bands in quasi-one-dimensional systems

    Science.gov (United States)

    Matsumoto, Karin; Ogura, Daisuke; Kuroki, Kazuhiko

    2018-01-01

    We study superconductivity in the Hubbard model on various quasi-one-dimensional lattices with coexisting wide and narrow bands originating from multiple sites within a unit cell, where each site corresponds to a single orbital. The systems studied are the two-leg and three-leg ladders, the diamond chain, and the crisscross ladder. These one-dimensional lattices are weakly coupled to form two-dimensional (quasi-one-dimensional) ones, and the fluctuation exchange approximation is adopted to study spin-fluctuation-mediated superconductivity. When one of the bands is perfectly flat and the Fermi level intersecting the wide band is placed in the vicinity of, but not within, the flat band, superconductivity arising from the interband scattering processes is found to be strongly enhanced owing to the combination of the light electron mass of the wide band and the strong pairing interaction due to the large density of states of the flat band. Even when the narrow band has finite bandwidth, the pairing mechanism still works since the edge of the narrow band, due to its large density of states, plays the role of the flat band. The results indicate the wide applicability of the high-Tc pairing mechanism due to coexisting wide and "incipient" narrow bands in quasi-one-dimensional systems.

  9. High temperature performance of polymer composites

    CERN Document Server

    Keller, Thomas

    2014-01-01

    The authors explain the changes in the thermophysical and thermomechanical properties of polymer composites under elevated temperatures and fire conditions. Using microscale physical and chemical concepts they allow researchers to find reliable solutions to their engineering needs on the macroscale. In a unique combination of experimental results and quantitative models, a framework is developed to realistically predict the behavior of a variety of polymer composite materials over a wide range of thermal and mechanical loads. In addition, the authors treat extreme fire scenarios up to more than 1000°C for two hours, presenting heat-protection methods to improve the fire resistance of composite materials and full-scale structural members, and discuss their performance after fire exposure. Thanks to the microscopic approach, the developed models are valid for a variety of polymer composites and structural members, making this work applicable to a wide audience, including materials scientists, polymer chemist...

  10. Magnetic neutron scattering resonance of high-¤Tc¤ superconductors in external magnetic fields: An SO(5) study

    DEFF Research Database (Denmark)

    Mortensen, Asger; Rønnow, Henrik Moodysson; Bruus, Henrik

    2000-01-01

    The magnetic resonance at 41 meV observed in neutron scattering studies of YBa2Cu3O7 holds a key position in the understanding of high-T-c, superconductivity. Within the SO(5) model for superconductivity and antiferromagnetism, we have calculated the effect of an applied magnetic field...... space we find that (i) the scattering amplitude is zero at (pi/a,pi/a), (ii) the resonance peak is split into a ring with radius pi/d centered at (pi/a, pi/a), d being the vortex lattice constant, and consequently, (iii) the splitting pi/d scales with the magnetic field as root B....... on the neutron scattering cross section of the magnetic resonance. In the presence of Abrikosov vortices, the neutron scattering cross section shows clear signatures of not only the fluctuations in the superconducting order parameter psi, but also the modulation of the phase of psi due to vortices. In reciprocal...

  11. High Performance High Temperature Thermoelectric Composites with Metallic Inclusions

    Science.gov (United States)

    Ma, James M. (Inventor); Bux, Sabah K. (Inventor); Fleurial, Jean-Pierre (Inventor); Ravi, Vilupanur A. (Inventor); Firdosy, Samad A. (Inventor); Star, Kurt (Inventor); Kaner, Richard B. (Inventor)

    2017-01-01

    The present invention provides a composite thermoelectric material. The composite thermoelectric material can include a semiconductor material comprising a rare earth metal. The atomic percent of the rare earth metal in the semiconductor material can be at least about 20%. The composite thermoelectric material can further include a metal forming metallic inclusions distributed throughout the semiconductor material. The present invention also provides a method of forming this composite thermoelectric material.

  12. Telecom 2-B and 2-C (TC2B and TC2C)

    Science.gov (United States)

    Dulac, J.; Alvarez, H.

    1991-01-01

    The DSN (Deep Space Network) mission support requirements for Telecom 2-B and 2-C (TC2B and TC2C) are summarized. These Telecom missions will provide high-speed data link applications, telephone, and television service between France and overseas territories as a follow-on to TC2A. Mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

  13. Microstructure and Properties of Laser Additive Manufacturing TC Bearing

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-07-01

    Full Text Available In order to solve the problem of uneven wear of TC bearing that conventional method brought and improve its service life,wear-resistant coating was fabricated on the surface of steel parts matrix with the method of laser additive manufacture. The Cr3C2/Fe based alloy was deposited by laser cladding technique on the inner-sleeve cylindrical and outer-sleeve bore of TC bearing with two different process parameters. The high-performance coating was obtained respectively, of cracks free,no pores and with good metallurgical quality. The morphology of the laser cladding coating was observed by scanning electronic microscope (SEM,the composition was analyzed by EDS,the phase transformation was characterized by XRD. The wear resistance,corrosion resistance and hardness of the laser cladding layer were tested by friction and wear tester,salt spray test chamber and digital micro-hardness tester respectively. The results show that the average micro-hardness of composite coating is HV700. The wear resistance of the composite coating is about 3 times as much as the Ni-based alloy. The corrosion resistance is close to 316L stainless steel.

  14. High-Performance Synthetic Fibers for Composites

    Science.gov (United States)

    1992-04-01

    FMI Composites LTD); Formation of fibergLass\\preform for composite coupling shaft; Undulating ribbon structure of graphene layers for a PAN-based c...ropes and cables, heat exchangers, bridge decking, and reinforced concrete . The key to increased consumption in these diverse end uses is reduced raw...cost while increasing their utility through toughening provides the opportunity for expanded CMC usage, such as in cement, concrete , bricks, and tile

  15. Solubility Control of Technetium Release from Saltstone by Tc02•xH20

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J.; Williams, Benjamin D.

    2013-11-12

    Saltstone leaching experiments were conducted using a modified single-pass flow-through method under anoxic conditions. The analytical results of leachates collected from these experiments were evaluated using thermodynamic modeling to determine if the data were consistent with potential solubility controlling phases. The results demonstrate that technetium concentrations in water in contact with Saltstone under anoxic conditions is controlled by the solubility of TcO2•xH2O (likely TcO2•1.6H2O). In our system equilibrium solubility appears to have been reached within two weeks at a concentration of approximately 1.5 x 10-6 M. This concentration is likely to vary as the composition of Saltstone pore fluid evolves over time. As the pH goes from the initial high values (~12.5-13) to lower values, the solubility of technetium will decrease significantly. The thermodynamic data used to determine the solubility of TcO2•1.6H2O were taken from the tabulation of critically selected thermodynamic data determined by the Nuclear Energy Agency. Solid phase characterization to demonstrate the presence of TcO2•xH2O was not possible due to the low concentrations of technetium in our samples. Previous solid phase characterization studies with cementitious waste forms that were very similar to our Saltstone samples as well as reaction products derived from reductive immobilization of TcO4- by amorphous FeS clearly indicate the presence of TcO2 with varying degrees of hydration. Although, the presence of TcSx or other reduced technetium sulfide phases in our samples cannot be ruled out, release of technetium from Saltstone will be controlled by TcO2•1.6H2O because of its higher solubility. Our results clearly demonstrate that the release mechanism of technetium from Saltstone under reducing conditions is solubility controlled by TcO2•xH2O (likely TcO2•1.6H2O); however, distribution coefficients (Kds), that describe sorption and not solubility, were calculated for

  16. A.C. loss of the high-Tc superconducting cable conductor; Koon chodendo keburu dotai no koryu sonshitsu

    Energy Technology Data Exchange (ETDEWEB)

    Kume, A.; Futaki, N.; Ono, K.; Sadakata, N.; Saito, T. [Fujikura Ltd., Tokyo (Japan); Hasegawa, T. [Showa Electric Wire and Cable Co., Ltd., Kanagawa (Japan); Nagaya, S. [Chubu Electric Power Co., Ltd., Aichi (Japan)

    1999-06-07

    High-temperature superconducting cable used in the liquid nitrogen circulation cooling was expected in the electric power field, because of an attempt to compact the cable size and possibly reduce the power transmission loss. In the multilayer spiral conductor laminated by which Bi-2223 phase silver sheath tape were spirally wound and insulated between layers, the drift problem that current distribution concentrated in the outer layer occurred, because the inductance of the internal layer was higher than that of the outer layer in the alternating current. In this study, for a purpose of attempting the drift countermeasure and reduction of AC loss, the transposition yarn twist segment was composed of Bi-2223 phase silver sheath tape, the transposition yarn twist conductor was manufactured with the structure of the transposition yarn twist segment spirally wound on a frame, and the alternating current characteristics were investigated. As the result, the phase shift of transferring current could be hardly observed on the silver sheath wire in the segment. (NEDO)

  17. High Specific Stiffness Shafts and Advanced Bearing Coatings for Gas Turbine Engines Final Report CRADA No. TC-1089-95

    Energy Technology Data Exchange (ETDEWEB)

    Barbee, Troy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chin, Herbert [United Technologies Corporation, East Hartford, CT (United States)

    2017-11-09

    At the time of the CRADA, the largest in-service gas-turbine aircraft engines strove for increased thrust and power density to meet the requirements for take-off thrust, given the increase in take-off gross weight (TOGW) associated with longer range transport requirements. The trend in modem turbo shaft engines was toward turbine shafts with higher and higher length-to-diameter ratios, which reduced the shaft critical speed. Using co nventional shaft materials, this lead to shafts that needed to operate near or above sensitive shaft bending critical speeds, therefore requiring multiple bearings and/ or multiple squeeze-film dampers to control the dynamic response. Using new materials and d esign concepts this project demonstrated the use of new shaft materials which could provide increased shaft speed range above existing maximum engine speeds without encountering a critic al speed event and high vector deflections. This increased main shaft speed also resulted in decreased bearing life associated with lower heat dissipation and higher centrifugal forces. Thus, a limited effort was devoted to feasibility of higher performance bearing coatings to mitigate the speed effects.

  18. Double Bag VARTM for High Temperature Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cost and size are limiting factors in efforts to produce high strength, high stiffness, and high temperature composite parts. To address these issues, new processes...

  19. Separation of tc from Uranium and development of metallic Technetium waste forms

    Science.gov (United States)

    Mausolf, Edward John

    The isotope Technetium-99 (99Tc) is a major fission product of the nuclear industry. In the last decade, approximately 20 tons of 99Tc have been produced by the US nuclear industry. Due to its long half-life (t1/2 = 214,000 yr), beta radiotoxicity, and high mobility as pertechnetate [TcO4]-, Tc represents long-term concern to the biosphere. Various options have been considered to manage 99Tc. One of them is its separation from spent fuel, conversion to the metal and incorporation into a metallic waste form for long-term disposal. After dissolution of spent fuel in nitric acid and extraction of U and Tc in organic media, previously developed methods can be used to separate Tc from U, convert the separate Tc stream to the metal and reuse the uranium component of the fuel. A variety of metallic waste forms, ranging from pure Tc metal to ternary Tc alloys combined with stainless steel (SS) and Zr are proposed. The goal of this work was to examine three major questions: What is the optimal method to separate Tc from U? After separation, what is the most efficient method to convert the Tc stream to Tc metal? Finally, what is the corrosion behavior of Tc metal, Tc-SS alloys and Tc-Zr-SS alloys in 0.01M NaCl? The goal is to predict the long term behavior of Tc metallic waste in a hypothetical storage environment. In this work, three methods have been used to separate Tc from U: anionic exchange resin, liquid-liquid extraction and precipitation. Of the three methods studied, anionic exchange resins is the most selective. After separation of Tc from U, three different methods were studied to convert the Tc stream to the metal: thermal treatment under hydrogen atmosphere, electrochemical and chemical reduction of pertechnetate in aqueous media. The thermal treatment of the Tc stream under hydrogen atmosphere is the preferred method to produce Tc metal. After Tc metal is isolated, it will be incorporated into a metal host phase. Three different waste forms were produced for

  20. {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer): a new integrin {alpha}{sub v}{beta}{sub 3}-targeted SPECT radiotracer with high tumor uptake and favorable pharmacokinetics

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jiyun [Purdue University, School of Health Sciences, West Lafayette, IN (United States); Peking University, Medical Isotopes Research Center, Beijing (China); Wang, Lijun; Kim, Young-Seung; Zhai, Shizhen; Liu, Shuang [Purdue University, School of Health Sciences, West Lafayette, IN (United States); Jia, Bing; Wang, Fan [Peking University, Medical Isotopes Research Center, Beijing (China)

    2009-11-15

    This report presents the synthesis of a cyclic RGD dimer conjugate, MAG{sub 2}-G{sub 3}-E[G{sub 3}-c(RGDfK)]{sub 2} (MAG{sub 2}-3G{sub 3}-dimer, G{sub 3} = Gly-Gly-Gly, MAG{sub 2} = S-benzoyl mercaptoacetylglycylglycyl), and evaluation of its {sup 99m}Tc complex, {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer), as a new radiotracer for imaging the tumor integrin {alpha}{sub v}{beta}{sub 3} expression. An in vitro displacement assay was used to determine the integrin {alpha}{sub v}{beta}{sub 3} binding affinity of MAG{sub 2}-3G{sub 3}-dimer against {sup 125}I-c(RGDyK) bound to U87MG human glioma cells. The athymic nude mice bearing U87MG glioma xenografts were used for biodistribution and planar imaging studies. We found that (1) MAG{sub 2} is such a highly effective bifunctional chelator that {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer) can be prepared in high yield (radiochemical purity >95%) and with high specific activity ({proportional_to}5 Ci/{mu}mol) using a kit formulation; (2) {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer) has very high solution stability in the kit matrix; and (3) {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer) has very fast clearance kinetics from the intestine, liver, and kidneys. Among the {sup 99m}Tc-labeled cyclic RGD peptides evaluated in the xenografted U87MG glioma models, {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer) has the best pharmacokinetics and tumor to background ratios (tumor/liver = 4.29 {+-} 1.00 at 30 min postinjection and 8.29 {+-} 1.50 at 120 min postinjection; tumor/kidney = 1.16 {+-} 0.19 at 30 min postinjection and 2.49 {+-} 0.25 at 120 min postinjection). Planar imaging studies showed that tumors in the glioma-bearing mice administered with {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer) can be visualized with excellent contrast as early as 15 min postinjection. {sup 99m}TcO(MAG{sub 2}-3G{sub 3}-dimer) was able to maintain its chemical integrity in kidneys (>80% intact) and liver (>95% intact) over the 2-h period. However, there was significant

  1. Preparation and evaluation of modified composition for lyophilized kits of [Cu(MIBI4]BF4 for [99mTc] technetium labeling

    Directory of Open Access Journals (Sweden)

    Marisa de Jesus de C. Lima

    2005-10-01

    Full Text Available The [Cu(MIBI4]BF4 complex was synthesized and different formulations for lyophilized kits that could be cost-effectively used with different routines in nuclear medicine laboratories were investigated. In one preparation the kit components were kept similar to the Cardiolite® , except that the SnCl2.2H2O concentration was increased to 0.150 mg. In a second formulation, component concentrations were reduced to 1/5 of the original value and the SnCl2.2H2O concentration was adjusted to 0.04 mg. These products were labeled with maximum activities of 55.5 GBq and 8.14 GBq, respectively, and have shown an average radiochemical purity of 95 %. Biodistribution of the products was assessed by dissection in mice and in rabbits, and did not show any statistical difference when compared to Cardiolite®. In the synthesis of [Cu(MIBI4]BF4 a new procedure was introduced for the synthesis of N-(2-methyl-propenyl-formamide, with the use of microwave radiation as heat source. This modification reduced the reaction time to 25 seconds, while maintaining a yield of 68%.Neste trabalho são apresentados dados relativos a síntese do complexo [Cu(MIBI4]BF4 e à utilização do mesmo para produção de kit liofilizado para obtenção do radiofármaco [[99mTc](MIBI6]+. No processo de síntese foi utilizado radiação de microondas como fonte de aquecimento em uma etapa do processo, permitindo que a reação fosse executada em 25 segundos, obtendo rendimento de 68 %. Na preparação dos kits liofilizados, um deles denominado FULL, nos quais a quantidade dos componentes foi mantida igual ao produto comercial Cardiolite®, e outro denominado FRACTION, nos quais as quantidades foram reduzidas a 1/5 do total, foram adicionadas quantidades extras de SnCl2.2H2O. Deste modo, tornou-se possível marcar os kits liofilizados com atividades máximas de 55,5 GBq e 8,14 GBq, respectivamente. A biodistribuição dos produtos marcados, em camundongos e coelhos, não mostrou diferen

  2. Modification of both d33 and TC in a potassium-sodium niobate ternary system.

    Science.gov (United States)

    Wu, Bo; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo

    2015-12-28

    In this work, we simultaneously achieved a giant d33 and a high TC in a lead-free piezoelectric ternary system of (1-x-y)K0.48Na0.52NbO3-xBiFeO3-yBi0.5Na0.5ZrO3 {(1-x-y)KNN-xBF-yBNZ}. Owing to the rhombohedral-orthorhombic-tetragonal (R-O-T) phase coexistence and the enhanced dielectric and ferroelectric properties, the ceramics with a composition of (x = 0.006, y = 0.04) show a giant d33 of ∼428 pC N(-1) together with a TC of ∼318 °C, thereby proving that the design of ternary systems is an effective way to achieve both high d33 and high TC in KNN-based materials. In addition, a good thermal stability for piezoelectricity was also observed in these ceramics (e.g., d33 > 390 pC N(-1), T ≤ 300 °C). This is the first time such a good comprehensive performance in potassium-sodium niobate materials has been obtained. As a result, we believe that this type of material system with both giant d33 and high TC is a promising candidate for high-temperature piezoelectric devices.

  3. Strength of VGCF/Al Composites for High Thermal Conductivity

    Science.gov (United States)

    Fukuchi, Kohei; Sasaki, Katsuhiko; Imanishi, Terumitsu; Katagiri, Kazuaki; Kakitsuji, Atsushi; Shimizu, Akiyuki

    In this paper, the evaluation of the strength of the VGCF/Aluminum composites which have high thermal conductivity is reported. VGCF (Vapor Growth Carbon Fiber) is a kind of the Carbon nanotube (CNT) which has very high thermal conductivity as well as CNT. The composites are made by spark plasma sintering. The stress-strain curves of the composites are obtained by the tensile tests and show that the composites have brittle behavior. The brittleness of the composites increases with increase in the volume fraction of VGCF. A numerical simulation based on the micromechanics is conducted to estimate nonlinear behavior in the elastic deformation and plastic deformation of the stress-strain relations of the composites. The theories of Eshelby, Mori-Tanaka, Weibull, and Ramberg-Osgood are employed for the numerical simulation. The simulations give some information of the microstructural change in the composite related to the volume fraction of VGCF.

  4. Ice hydrometeor profile retrieval algorithm for high-frequency microwave radiometers: application to the CoSSIR instrument during TC4

    Directory of Open Access Journals (Sweden)

    K. F. Evans

    2012-09-01

    Full Text Available A Bayesian algorithm to retrieve profiles of cloud ice water content (IWC, ice particle size (Dme, and relative humidity from millimeter-wave/submillimeter-wave radiometers is presented. The first part of the algorithm prepares an a priori file with cumulative distribution functions (CDFs and empirical orthogonal functions (EOFs of profiles of temperature, relative humidity, three ice particle parameters (IWC, Dme, distribution width, and two liquid cloud parameters. The a priori CDFs and EOFs are derived from CloudSat radar reflectivity profiles and associated ECMWF temperature and relative humidity profiles combined with three cloud microphysical probability distributions obtained from in situ cloud probes. The second part of the algorithm uses the CDF/EOF file to perform a Bayesian retrieval with a hybrid technique that uses Monte Carlo integration (MCI or, when too few MCI cases match the observations, uses optimization to maximize the posterior probability function. The very computationally intensive Markov chain Monte Carlo (MCMC method also may be chosen as a solution method. The radiative transfer model assumes mixtures of several shapes of randomly oriented ice particles, and here random aggregates of spheres, dendrites, and hexagonal plates are used for tropical convection. A new physical model of stochastic dendritic snowflake aggregation is developed. The retrieval algorithm is applied to data from the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR flown on the ER-2 aircraft during the Tropical Composition, Cloud and Climate Coupling (TC4 experiment in 2007. Example retrievals with error bars are shown for nadir profiles of IWC, Dme, and relative humidity, and nadir and conical scan swath retrievals of ice water path and average Dme. The ice cloud retrievals are evaluated by retrieving integrated 94 GHz backscattering from CoSSIR for comparison

  5. High power composite cavity fiber laser oscillator at 1120 nm

    Science.gov (United States)

    Wang, Jianming; Li, Cheng; Yan, Dapeng

    2017-12-01

    A high power composite cavity fiber laser oscillator at 1120 nm is demonstrated experimentally. Performances of the 1120 nm single fiber laser oscillator and the composite cavity are investigated and compared, and the parasitic oscillation created by the strong amplified spontaneous emission (ASE) can be suppressed effectively in the composite cavity scheme. 2.04-kW 1120-nm signal light with a good beam quality (M2=1.15) is obtained, and the optical conversion efficiency of the composite cavity fiber laser oscillator is about 63% in the experiment. The compact architecture of composite cavity provides an effective scheme for power scaling of long wavelength lasers.

  6. Quantitative analysis of relationships between irradiation parameters and the reproducibility of cyclotron-produced (99m)Tc yields.

    Science.gov (United States)

    Tanguay, J; Hou, X; Buckley, K; Schaffer, P; Bénard, F; Ruth, T J; Celler, A

    2015-05-21

    Cyclotron production of (99m)Tc through the (100)Mo(p,2n) (99m)Tc reaction channel is actively being investigated as an alternative to reactor-based (99)Mo generation by nuclear fission of (235)U. An exciting aspect of this approach is that it can be implemented using currently-existing cyclotron infrastructure to supplement, or potentially replace, conventional (99m)Tc production methods that are based on aging and increasingly unreliable nuclear reactors. Successful implementation will require consistent production of large quantities of high-radionuclidic-purity (99m)Tc. However, variations in proton beam currents and the thickness and isotopic composition of enriched (100)Mo targets, in addition to other irradiation parameters, may degrade reproducibility of both radionuclidic purity and absolute (99m)Tc yields. The purpose of this article is to present a method for quantifying relationships between random variations in production parameters, including (100)Mo target thicknesses and proton beam currents, and reproducibility of absolute (99m)Tc yields (defined as the end of bombardment (EOB) (99m)Tc activity). Using the concepts of linear error propagation and the theory of stochastic point processes, we derive a mathematical expression that quantifies the influence of variations in various irradiation parameters on yield reproducibility, quantified in terms of the coefficient of variation of the EOB (99m)Tc activity. The utility of the developed formalism is demonstrated with an example. We show that achieving less than 20% variability in (99m)Tc yields will require highly-reproducible target thicknesses and proton currents. These results are related to the service rate which is defined as the percentage of (99m)Tc production runs that meet the minimum daily requirement of one (or many) nuclear medicine departments. For example, we show that achieving service rates of 84.0%, 97.5% and 99.9% with 20% variations in target thicknesses requires producing on average

  7. Quantitative analysis of relationships between irradiation parameters and the reproducibility of cyclotron-produced 99mTc yields

    Science.gov (United States)

    Tanguay, J.; Hou, X.; Buckley, K.; Schaffer, P.; Bénard, F.; Ruth, T. J.; Celler, A.

    2015-05-01

    Cyclotron production of 99mTc through the 100Mo(p,2n) 99mTc reaction channel is actively being investigated as an alternative to reactor-based 99Mo generation by nuclear fission of 235U. An exciting aspect of this approach is that it can be implemented using currently-existing cyclotron infrastructure to supplement, or potentially replace, conventional 99mTc production methods that are based on aging and increasingly unreliable nuclear reactors. Successful implementation will require consistent production of large quantities of high-radionuclidic-purity 99mTc. However, variations in proton beam currents and the thickness and isotopic composition of enriched 100Mo targets, in addition to other irradiation parameters, may degrade reproducibility of both radionuclidic purity and absolute 99mTc yields. The purpose of this article is to present a method for quantifying relationships between random variations in production parameters, including 100Mo target thicknesses and proton beam currents, and reproducibility of absolute 99mTc yields (defined as the end of bombardment (EOB) 99mTc activity). Using the concepts of linear error propagation and the theory of stochastic point processes, we derive a mathematical expression that quantifies the influence of variations in various irradiation parameters on yield reproducibility, quantified in terms of the coefficient of variation of the EOB 99mTc activity. The utility of the developed formalism is demonstrated with an example. We show that achieving less than 20% variability in 99mTc yields will require highly-reproducible target thicknesses and proton currents. These results are related to the service rate which is defined as the percentage of 99mTc production runs that meet the minimum daily requirement of one (or many) nuclear medicine departments. For example, we show that achieving service rates of 84.0%, 97.5% and 99.9% with 20% variations in target thicknesses requires producing on average 1.2, 1.5 and 1.9 times the

  8. Development of Composite Materials with High Passive Damping Properties

    National Research Council Canada - National Science Library

    Crocker, Malcolm J

    2006-01-01

    ... structure with high damping. Composite sandwich structures have several advantages, such as their high strength-to-weight ratio, excellent thermal insulation, and good performance as water and vapor barriers...

  9. The Theobroma cacao B3 domain transcription factor TcLEC2 plays a duel role in control of embryo development and maturation.

    Science.gov (United States)

    Zhang, Yufan; Clemens, Adam; Maximova, Siela N; Guiltinan, Mark J

    2014-04-24

    The Arabidopsis thaliana LEC2 gene encodes a B3 domain transcription factor, which plays critical roles during both zygotic and somatic embryogenesis. LEC2 exerts significant impacts on determining embryogenic potential and various metabolic processes through a complicated genetic regulatory network. An ortholog of the Arabidopsis Leafy Cotyledon 2 gene (AtLEC2) was characterized in Theobroma cacao (TcLEC2). TcLEC2 encodes a B3 domain transcription factor preferentially expressed during early and late zygotic embryo development. The expression of TcLEC2 was higher in dedifferentiated cells competent for somatic embryogenesis (embryogenic calli), compared to non-embryogenic calli. Transient overexpression of TcLEC2 in immature zygotic embryos resulted in changes in gene expression profiles and fatty acid composition. Ectopic expression of TcLEC2 in cacao leaves changed the expression levels of several seed related genes. The overexpression of TcLEC2 in cacao explants greatly increased the frequency of regeneration of stably transformed somatic embryos. TcLEC2 overexpressing cotyledon explants exhibited a very high level of embryogenic competency and when cultured on hormone free medium, exhibited an iterative embryogenic chain-reaction. Our study revealed essential roles of TcLEC2 during both zygotic and somatic embryo development. Collectively, our evidence supports the conclusion that TcLEC2 is a functional ortholog of AtLEC2 and that it is involved in similar genetic regulatory networks during cacao somatic embryogenesis. To our knowledge, this is the first detailed report of the functional analysis of a LEC2 ortholog in a species other then Arabidopsis. TcLEC2 could potentially be used as a biomarker for the improvement of the SE process and screen for elite varieties in cacao germplasm.

  10. CARBON FIBER COMPOSITES IN HIGH VOLUME

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Charles David [ORNL; Das, Sujit [ORNL; Jeon, Dr. Saeil [Volvo Trucks North America

    2014-01-01

    Vehicle lightweighting represents one of several design approaches that automotive and heavy truck manufacturers are currently evaluating to improve fuel economy, lower emissions, and improve freight efficiency (tons-miles per gallon of fuel). With changes in fuel efficiency and environmental regulations in the area of transportation, the next decade will likely see considerable vehicle lightweighting throughout the ground transportation industry. Greater use of carbon fiber composites and light metals is a key component of that strategy. This paper examines the competition between candidate materials for lightweighting of heavy vehicles and passenger cars. A 53-component, 25 % mass reduction, body-in-white cost analysis is presented for each material class, highlighting the potential cost penalty for each kilogram of mass reduction and then comparing the various material options. Lastly, as the cost of carbon fiber is a major component of the elevated cost of carbon fiber composites, a brief look at the factors that influence that cost is presented.

  11. Direct {sup 99m}Tc labeling of Herceptin (trastuzumab) by {sup 99m}Tc(I) tricarbonyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.-J.; Yen, C.-L.; Lo, S.-T.; Chen, K.-T. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lo, J.-M. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China)], E-mail: jmlo@mx.nthu.edu.tw

    2008-03-15

    By simply incubating Herceptin (trastuzumab) with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +} ion in saline, a significant yield of {sup 99m}Tc-labeled trastuzumab was found to be achievable. The effective labeling may be based on that trastuzumab is inherent with endogenous histidine group to which {sup 99m}Tc(I) tricarbonyl ion can be strongly bound. For practical {sup 99m}Tc labeling processing, trastuzumab was purified beforehand from the commercial product, Herceptin (Genentech) via size exclusion chromatography to remove the excipient, {alpha}-histidine and a high-labeled yield could be obtained by incubating the purified trastuzumab with [{sup 99m}Tc(CO){sub 3}(OH{sub 2}){sub 3}]{sup +}. Retention of bioactivity of the {sup 99m}Tc(I)-labeled trastuzumab was validated using a cell binding test.

  12. High temperature metal matrix composites for future aerospace systems

    Science.gov (United States)

    Stephens, Joseph R.

    1988-01-01

    Research was conducted on metal matrix composites and intermetallic matrix composites to understand their behavior under anticipated future operating conditions envisioned for aerospace power and propulsion systems of the 21st century. Extremes in environmental conditions, high temperature, long operating lives, and cyclic conditions dictate that the test evaluations not only include laboratory testing, but simulated flight conditions. The various processing techniques employed to fabricate composites are discussed along with the basic research underway to understand the behavior of high temperature composites, and the relationship of this research to future aerospace systems.

  13. Liquid crystallinity driven highly aligned large graphene oxide composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of); Kim, Sang Ouk, E-mail: sangouk.kim@kaist.ac.kr [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of)

    2015-04-15

    Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

  14. Research progress of Tc1/Mariner superfamily.

    Science.gov (United States)

    Shen, Dan; Chen, Cai; Wang, Sai-sai; Chen, Wei; Gao, Bo; Song, Cheng-yi

    2017-01-20

    With the rapid improvement of sequencing techniques, more and more genome annotations reveal the transposons are the important components of most genomes and present on almost all organisms. Among them, the Tc1/Mariner superfamily represents the most widespread DNA transposons. Until now, fourteen active Tc1/Mariner transposons (Minos, Mos1, etc.) have been identified and some highly active artificial transposons have been created through molecular reconstruction, such as Sleeping Beauty (SB). The transposons such as SB and Mos1 have been widely used as gene transfer vectors in the fields of transgenosis, gene trapping and gene therapy. In this review, we summarize the structure, classification, distributions, transposition mechanism and excavations of active members of Tc1/Mariner as well as its application in the fields of transgenesis, gene trapping and gene therapy.

  15. High Performance Graphene Oxide Based Rubber Composites

    OpenAIRE

    Yingyan Mao; Shipeng Wen; Yulong Chen; Fazhong Zhang; Pierre Panine; Tung W. Chan; Liqun Zhang; Yongri Liang; Li Liu

    2013-01-01

    In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical prope...

  16. Delamination toughness of ultra high molecular weight polyethylene (UHMWPE composites

    Directory of Open Access Journals (Sweden)

    Casas-Rodriguez J.P.

    2012-08-01

    Full Text Available Ultra high molecular weight polyethylene (UHMWPE fibre reinforced composites are an important group of material for armours solutions, where their unique combination of properties could be utilized. A commonly observed failure mode in this kind of unidirectional laminated composites under impact ballistic is delamination between the composite layers. In the present study, an investigation on the delamination toughness behaviour exhibited by UHMWPE composites laminated was made. The interlaminar Mode II critical strain energy release rates of (UHMWPE fibre reinforced composites were characterized using the End Notch Flexural (ENF test. Critical strain energy release rate was obtained from the load – deflection test data using the beam theory expression. It was found that the energy release rate of the composite exhibited a very low value of around 60J/m2 using a moulding pressure of approximately 1200 psi. In order to analyse the delamination resistance of composite, the effects of changing the manufacture process variables and the use of a thermoplastic adhesive film in the composites were investigated. The composite laminates were produced by hot compressing moulding using a film-stacking procedure. It was found that the damage resistance of the UHMWPE composite was influenced by the manufacture method, which affects the Mode II interlaminar fracture toughness and the ballistic response of composites.

  17. In Vitro-Generated Tc17 Cells Present a Memory Phenotype and Serve As a Reservoir of Tc1 Cells In Vivo

    Directory of Open Access Journals (Sweden)

    Felipe Flores-Santibáñez

    2018-02-01

    Full Text Available Memory CD8+ T cells are ideal candidates for cancer immunotherapy because they can mediate long-term protection against tumors. However, the therapeutic potential of different in vitro-generated CD8+ T cell effector subsets to persist and become memory cells has not been fully characterized. Type 1 CD8+ T (Tc1 cells produce interferon-γ and are endowed with high cytotoxic capacity, whereas IL-17-producing CD8+ T (Tc17 cells are less cytotoxic but display enhanced self-renewal capacity. We sought to evaluate the functional properties of in vitro-generated Tc17 cells and elucidate their potential to become long lasting memory cells. Our results show that in vitro-generated Tc17 cells display a greater in vivo persistence and expansion in response to secondary antigen stimulation compared to Tc1 cells. When transferred into recipient mice, Tc17 cells persist in secondary lymphoid organs, present a recirculation behavior consistent with central memory T cells, and can shift to a Tc1 phenotype. Accordingly, Tc17 cells are endowed with a higher mitochondrial spare respiratory capacity than Tc1 cells and express higher levels of memory-related molecules than Tc1 cells. Together, these results demonstrate that in vitro-generated Tc17 cells acquire a central memory program and provide a lasting reservoir of Tc1 cells in vivo, thus supporting the use of Tc17 lymphocytes in the design of novel and more effective therapies.

  18. Composition of grain and forage from insect-protected and herbicide-tolerant corn, MON 89034 × TC1507 × MON 88017 × DAS-59122-7 (SmartStax), is equivalent to that of conventional corn (Zea mays L.).

    Science.gov (United States)

    Lundry, Denise R; Burns, J Austin; Nemeth, Margaret A; Riordan, Susan G

    2013-02-27

    Monsanto Company and Dow AgroSciences LLC have developed the combined-trait corn product MON 89034 × TC1507 × MON 88017 × DAS-59122-7 (SmartStax, a registered trademark of Monsanto Technology LLC). The combination of four biotechnology-derived events into a single corn product (stacking) through conventional breeding provides broad protection against lepidopteran and corn rootworm insect pests as well as tolerance to the glyphosate and glufosinate-ammonium herbicide families. The purpose of the work described here was to assess whether the nutrient, antinutrient, and secondary metabolite levels in grain and forage tissues of the combined-trait product are comparable to those in conventional corn. Compositional analyses were conducted on grain and forage from SmartStax, a near-isogenic conventional corn hybrid (XE6001), and 14 conventional reference hybrids, grown at multiple locations across the United States. No statistically significant differences between SmartStax and conventional corn were observed for the 8 components analyzed in forage and for 46 of the 52 components analyzed in grain. The six significant differences observed in grain components (p corn, as previously demonstrated for the single-event products.

  19. Spectroscopic Imaging Scanning Tunneling Microscopy Studies of Electronic Structure in the Superconducting and Pseudogap Phases of Cuprate High-Tc Superconductors

    Science.gov (United States)

    Fujita, Kazuhiro; Schmidt, Andrew R.; Kim, Eun-Ah; Lawler, Michael J.; Lee, Dung Hai; Davis, J. C.; Eisaki, Hiroshi; Uchida, Shin-ichi

    2012-01-01

    phase diagram and the mechanism of high-Tc superconductivity, represents one of a key challenges for cuprate studies.

  20. High-Speed, Three Dimensional Object Composition Mapping Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, M Y

    2001-02-14

    This document overviews an entirely new approach to determining the composition--the chemical-elemental, isotopic and molecular make-up--of complex, highly structured objects, moreover with microscopic spatial resolution in all 3 dimensions. The front cover depicts the new type of pulsed laser system at the heart of this novel technology under adjustment by Alexis Wynne, and schematically indicates two of its early uses: swiftly analyzing the 3-D composition governed structure of a transistor circuit with both optical and mass-spectrometric detectors, and of fossilized dinosaur and turtle bones high-speed probed by optical detection means. Studying the composition-cued 3-D micro-structures of advanced composite materials and the microscopic scale composition-texture of biological tissues are two near-term examples of the rich spectrum of novel applications enabled by this field-opening analytic tool-set.

  1. Lightweight, High Strength Nano-Composite Magnesium for Radiators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase I SBIR, Terves will develop processing routes to produce high thermal conductivity magnesium composites for use in heat transfer applications such as...

  2. High Strain Rate Characterisation of Composite Materials

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Normann Wilken

    -reinforced polymers, were considered, and it was first shown that the loading history controls equilibrium process. Then the High-speed servo-hydraulic test machine was analysed in terms its ability to create a state of constant strain rate in the specimen. The invertible inertial forces in the load train prevented...... a linear elastic specimen to reach a state of constant strain rate before fracture. This was in contrast to ductile materials, which are widely tested with for the High-speed servohydraulic test machine. The development of the analysis and the interpretation of the results, were based on the experience...... from designing and constructing a high-speed servo-hydraulic test machine and by performing a comprehensive test series. The difficulties encountered in the test work could be addressed with the developed analysis. The conclusion was that the High-speed servo-hydraulic test machine is less suited...

  3. GEOCHEMISTRY AND Nd - ISOTOPIC COMPOSITION OF HIGH ...

    African Journals Online (AJOL)

    Mgina

    Fault (Fig. 1). These rocks represent a narrow band of recrystallized, sheared and altered felsic volcanic and volcanoclastic rocks (including lapilli tuff) that are interlayered with detrital ... methods of Makishima and Nakamura. (1997) for Rb, Sr, Y, Cs, Ba, ... samples can be classified as rhyolites and based on their high silica ...

  4. Highly piezoelectric Biocompatible and Soft Composite Fibers

    Science.gov (United States)

    Jakli, Antal; Morvan, Jason; Buyuktanir, Ebru; West, John

    2012-02-01

    We report the fabrication of highly piezoelectric biocompatible soft fibers containing Barium Titanate (BT) ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crystal barium titanate films. We demonstrate that the observed super-piezoelectricity results from the electrospinning induced polar alignment of the ferroelectric particles and the increased surface area compared to single crystal films. Due to the biocompatibility of PLA that encases the ferroelectric particles, these mats can be applied even in biological applications such as bio-sensors, artificial muscles and energy harvesting devices.

  5. Highly explosive nanosilicon-based composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Clement, D.; Diener, J.; Gross, E.; Kuenzner, N.; Kovalev, D. [Technical University of Munich, Physics Department, James-Franck-Str., 85747 Garching (Germany); Timoshenko, V.Yu. [Moscow State M.V. Lomonosov University, Physics Department, 119899 Moscow (Russian Federation)

    2005-06-01

    We present a highly explosive binary system based on porous silicon layers with their pores filled with solid oxidizers. The porous layers are produced by a standard electrochemical etching process and exhibit properties that are different from other energetic materials. Its production is completely compatible with the standard silicon technology and full bulk silicon wafers can be processed and therefore a large number of explosive elements can be produced simultaneously. The application-relevant parameters: the efficiency and the long-term stability of various porous silicon/oxidizer systems have been studied in details. Structural properties of porous silicon, its surface termination, the atomic ratio of silicon to oxygen and the chosen oxidizers were optimized to achieve the highest efficiency of the explosive reaction. This explosive system reveals various possible applications in different industrial fields, e.g. as a novel, very fast airbag igniter. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Breakfast Composition in Junior High School Students

    Directory of Open Access Journals (Sweden)

    Sheila Devi

    2015-12-01

    Full Text Available Background: Adolescence is a time of rapid development that requires higher nutrient intake levels than in adulthood. However the habit of skipping breakfast has become very popular among adolescents. Skipping breakfast has negative effects such as difficulty in concentrating, growth impairment and decrease academic performance. Therefore, this study was conducted to identify the breakfast composisition of early adolescents in Jatinangor, Sumedang, Indonesia. Methods: A cross sectional study with non-probability sampling method, was conducted in a junior high school Jatinangor during the month of July 2013. Ninety six participants were included in this study. All the participants underwent an interview about the food intake for breakfast in seven days using eating pattern recall guidelines. Results: Overall, 37% of the respondents skipped breakfast. The mean of total calories among the adolescents who consumed breakfast was 286.06 (187.89 kcal. The amount of carbohydrate, fat and protein consumed was 29.23 (19.93 gram, 13.93 (13.29 gram and 8.78 (6.11 gram accordingly. The main reason for adolescent to skip breakfast was lack of time. Conclusions: Majority of the respondents have their breakfast before they go to school. Overall, the total calories comsumed is sufficient however the amount of protein consumed is low.

  7. Activation of [(99(m))TcO4](-) by phosphonium cations.

    Science.gov (United States)

    Braband, Henrik; Benz, Michael; Tooyama, Yuji; Alberto, Roger

    2014-04-21

    Phosphonium salts in solution or bound to solid phase supports interact with the robust [(99(m))TcO4](-) anion in neutral water. This activated form of [(99(m))TcO4](-) represents a source for complexes with the fac-{(99m)Tc(VII)O3}(+) core, which can be synthesized in high yields and purity.

  8. Automated composite ellipsoid modelling for high frequency GTD analysis

    Science.gov (United States)

    Sze, K. Y.; Rojas, R. G.; Klevenow, F. T.; Scheick, J. T.

    1991-01-01

    The preliminary results of a scheme currently being developed to fit a composite ellipsoid to the fuselage of a helicopter in the vicinity of the antenna location are discussed under the assumption that the antenna is mounted on the fuselage. The parameters of the close-fit composite ellipsoid would then be utilized as inputs into NEWAIR3, a code programmed in FORTRAN 77 for high frequency Geometrical Theory of Diffraction (GTD) Analysis of the radiation of airborne antennas.

  9. Comparison of a new Tc-99m renal function agent, Tc-99m mercaptoacetyltriglycine, with I-131 OIH

    Energy Technology Data Exchange (ETDEWEB)

    Eshima, D.; Fritzberg, A.R.; Kasina, S.; Johnson, D.L.; Taylor, A.

    1985-05-01

    The search for a Tc-99m replacement for I-131 hippurate (OIH) has led to the synthesis of (mercaptoacetyltriglycine) Tc-99m MAG/sub 3/, a N/sub 3/S derivative with a single stereochemical form, amenable to it formulation. Mouse biodistribution studies in control and probenecid treated animals indicated that renal excretion of Tc-99m MAG/sub 3/ was superior to OIH in both groups of animals. Protein binding studies, constant infusion clearance studies and extraction efficiencies were performed in rats to determine the potential of this agent for evaluation of renal function. In rat plasma TC-99m MAG/sub 3/ was 78% protein bound while OIH was 34% bound. The constant infusion clearance values for Tc-99m MAG/sub 3/ and OIH were 2.70 and 2.11 ml/min/ 100 gm body weight respectively. Clearance values were determined in the presence of IV administered competitive inhibitors, probenecid and para-aminohippuric acid (PAH). Extraction efficiency studies were performed in rats by arterio-venous differences for Tc-99m MAG/sub 3/ and OIH. Tc-99m MAG/sub 3/ was found to have an extraction efficiency of 84.8% while 69.4% was found for OIH. In summary, TC-99m MAG/sub 3/ is cleared more rapidly than OIH in normal rodents with high specificity. Its clearance, in the presence of tubular transport inhibitors, was similar to OIH when corrected for GFR.

  10. High Performance Fiber Reinforced Cement Composites 6 HPFRCC 6

    CERN Document Server

    Reinhardt, Hans; Naaman, A

    2012-01-01

    High Performance Fiber Reinforced Cement Composites (HPFRCC) represent a class of cement composites whose stress-strain response in tension undergoes strain hardening behaviour accompanied by multiple cracking, leading to a high strain prior to failure. The primary objective of this International Workshop was to provide a compendium of up-to-date information on the most recent developments and research advances in the field of High Performance Fiber Reinforced Cement Composites. Approximately 65 contributions from leading world experts are assembled in these proceedings and provide an authoritative perspective on the subject. Special topics include fresh and hardening state properties; self-compacting mixtures; mechanical behavior under compressive, tensile, and shear loading; structural applications; impact, earthquake and fire resistance; durability issues; ultra-high performance fiber reinforced concrete; and textile reinforced concrete. Target readers: graduate students, researchers, fiber producers, desi...

  11. High efficiency tantalum-based ceramic composite structures

    Science.gov (United States)

    Stewart, David A. (Inventor); Leiser, Daniel B. (Inventor); DiFiore, Robert R. (Inventor); Katvala, Victor W. (Inventor)

    2010-01-01

    Tantalum-based ceramics are suitable for use in thermal protection systems. These composite structures have high efficiency surfaces (low catalytic efficiency and high emittance), thereby reducing heat flux to a spacecraft during planetary re-entry. These ceramics contain tantalum disilicide, molybdenum disilicide and borosilicate glass. The components are milled, along with a processing aid, then applied to a surface of a porous substrate, such as a fibrous silica or carbon substrate. Following application, the coating is then sintered on the substrate. The composite structure is substantially impervious to hot gas penetration and capable of surviving high heat fluxes at temperatures approaching 3000.degree. F. and above.

  12. High-speed Impact Modelling and Testing of Dyneema Composite

    OpenAIRE

    Heru Utomo, B.D.

    2011-01-01

    Dyneema (Ultra High Molecular Weight Polyethylene – UHMW PE) is a high performance material that is used in many applications. These applications vary from leisure articles such as sails and kite wires to surgical wires and personal protection products. The reason that Dyneema outperforms many other materials is that it possesses a combination of the following properties: high strength, high stiffness and low density. Describing Dyneema, and especially Dyneema composite, is -however- challeng...

  13. Side-suspended High-Tc Superconducting Maglev Prototype Vehicle Running at a High Speed in an Evacuated Circular Test Track

    Science.gov (United States)

    Zhou, Dajin; Zhao, Lifeng; Cui, Chenyu; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

    2017-07-01

    High-T c superconductor (HTS) and permanent magnetic guideway (PMG) based maglev train is intensively studied in China, Japan, Germany and Brazil, mainly through static or vibration test. Amongst these studies, only a few of reports are available for the direct and effective assessment on the dynamic performance of the HTS maglev vehicle by running on a straight or circular PMG track. The highest running speed of these experiments is lower than 50 km/h. In this paper, a side-suspended HTS permanent magnetic guideway maglev system was proposed and constructed in order to increase the running speed in a circular track. By optimizing the arrangement of YBCO bulks besides the PMG, the side-suspended HTS maglev prototype vehicle was successfully running stably at a speed as high as 150 km/h in a circular test track with 6.5 m in diameter, and in an evacuated tube environment, in which the pressure is 5 × 103 Pa.

  14. Study of the crystal structure of the high Tc superconductor Hg1-xRe xBa2Ca2Cu3O8+δ by using EXAFS, XANES and XRD

    Directory of Open Access Journals (Sweden)

    Luis Gallego Martinez

    2008-06-01

    Full Text Available Hg based superconducting ceramics present the highest critical temperatures ever reported, particularly the phase 1223 with the highest Tc so far obtained -135 K. However, these compounds are obtained by a complex synthesis route and suffer degradation at ambient atmosphere. This disadvantage may be overcome by doping with an appropriate amount of Re. Samples of nominal composition Hg0.82Re0.18Ba2Ca2Cu3O8+δ having different oxygen contents were studied by X ray absorption and diffraction techniques. Using XANES we determined the Re valence = +7 in an octahedral distorted coordination. We determined the distances of Re-O bonds (1.85 Å and 2.10 Å by EXAFS. XRD Rietveld fits showed segregation of two superconducting phases with distinct lattice parameters. The main phase is associated with Hg, Re-1223 with higher oxygen content, and the secondary superconducting phase is related to undoped Hg-1223.

  15. High elastic modulus nanopowder reinforced resin composites for dental applications

    Science.gov (United States)

    Wang, Yijun

    2007-12-01

    Dental restorations account for more than $3 billion dollars a year on the market. Among them, all-ceramic dental crowns draw more and more attention and their popularity has risen because of their superior aesthetics and biocompatibility. However, their relatively high failure rate and labor-intensive fabrication procedure still limit their application. In this thesis, a new family of high elastic modulus nanopowder reinforced resin composites and their mechanical properties are studied. Materials with higher elastic modulus, such as alumina and diamond, are used to replace the routine filler material, silica, in dental resin composites to achieve the desired properties. This class of composites is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Most of the work focuses on nano-sized Al2O3 (average particle size 47 nm) reinforcement in a polymeric matrix with 50:50 Bisphenol A glycidyl methacrylate (Bis-GMA): triethylene glycol dimethacrylate (TEGDMA) monomers. Surfactants, silanizing agents and primers are examined to obtain higher filler levels and enhance the bonding between filler and matrix. Silane agents work best. The elastic modulus of a 57.5 vol% alumina/resin composite is 31.5 GPa compared to current commercial resin composites with elastic modulus alumina, diamond/resin composites are studied. An elastic modulus of about 45 GPa is obtained for a 57 vol% diamond/resin composite. Our results indicate that with a generally monodispersed nano-sized high modulus filler, relatively high elastic modulus resin-based composite cements are possible. Time-dependent behavior of our resin composites is also investigated. This is valuable for understanding the behavior of our material and possible fatigue testing in the future. Our results indicate that with effective coupling agents and higher filler loading, viscous flow can be greatly decreased due to the

  16. The Tribolium castaneum cell line TcA: a new tool kit for cell biology.

    Science.gov (United States)

    Silver, Kristopher; Jiang, Hongbo; Fu, Jinping; Phillips, Thomas W; Beeman, Richard W; Park, Yoonseong

    2014-10-30

    The red flour beetle, Tribolium castaneum, is an agriculturally important insect pest that has been widely used as a model organism. Recently, an adherent cell line (BCIRL-TcA-CLG1 or TcA) was developed from late pupae of the red flour beetle. Next generation transcriptome sequencing of TcA cells demonstrated expression of a wide variety of genes associated with specialized functions in chitin metabolism, immune responses and cellular and systemic RNAi pathways. Accordingly, we evaluated the sensitivity of TcA cells to dsRNA to initiate an RNAi response. TcA cells were highly sensitive to minute amounts of dsRNA, with a minimum effective dose of 100 pg/mL resulting in significant suppression of gene expression. We have also developed a plasmid containing two TcA-specific promoters, the promoter from the 40S ribosomal protein subunit (TC006550) and a bi-directional heat shock promoter (TcHS70) from the intergenic space between heat shock proteins 68a and b. These promoters have been employed to provide high levels of either constitutive (TC006550) or inducible (TcHS70) gene expression of the reporter proteins. Our results show that the TcA cell line, with its sensitivity to RNAi and functional TcA-specific promoters, is an invaluable resource for studying basic molecular and physiological questions.

  17. Telecom 2-A (TC2A)

    Science.gov (United States)

    Dulac, J.; Latour, J.

    1991-01-01

    The DSN (Deep Space Network) mission support requirements for Telecom 2-A (TC2A) are summarized. The Telecom 2-A will provide high-speed data link applications, telephone, and television service between France and overseas territories. The mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

  18. Properties of recycled high density polyethylene and coffee dregs composites

    Directory of Open Access Journals (Sweden)

    Sibele Piedade Cestari

    2013-01-01

    Full Text Available Composites of recycled high density polyethylene (HDPE-R and coffee dregs (COFD were elaborated. The blends were made at the proportions of 100-0, 90-10, 80-20, 70-30, 60-40, 50-50 and 40-60% polymer-filler ratio. The materials were evaluated through scanning electron microscopy (SEM, differential scanning calorimetry (DSC, thermogravimetry/derivative thermogravimetry (TGA, and compressive resistance test. The compounding was done using a two-stage co-kneader system extruder, and then cylindrical specimens were injection molded. All composites had a fine dispersion of the COFD into the polymeric matrix. The composites degraded in two steps. The first one was in a temperature lower than the neat HDPE, but higher than the average processing temperature of the polymer. The melting temperature and the degree of crystallinity of the composites resulted similar to the neat HDPE ones. The compressive moduli of the composites resulted similar to the neat polymer one. The results show that these composites have interesting properties as a building material.

  19. High-Temperature, Self-Lubricating Ceramic/Metal Composites

    Science.gov (United States)

    Sliney, Harold E.; Dellacorte, Christopher; Bogdanski, Michael S.; Edwards, Philip

    1994-01-01

    Four documents provide detailed information on ceramic/metal composite materials that are self-lubricating at temperatures as high as 900 degrees C. Materials used in bearings and seals for turbomachines, new energy-efficient automotive engines, power generators, pumps, and furnaces.

  20. Evaluation of Additive Manufacturing for High Volume Composite Part Molds

    Energy Technology Data Exchange (ETDEWEB)

    Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kunc, Vlastimil [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lokitz, Bradley S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Springfield, Robert M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-01

    ORNL worked with TruDesign, LLC to develop viable coating solutions to enable the use of large scale 3D printing for both low-temperature and high-temperature composite molds. This project resulted in two commercial products and successfully demonstrated the use of printed molds for autoclave processing for the first time.

  1. Geochemistry and Nd - isotopic composition of high silica rhyolites ...

    African Journals Online (AJOL)

    The samples have very low concentration of the transition elements, Sr (3.13 – 48.4 ppm) and very large negative Europium anomalies (Eu/Eu* = 0.27 – 0.48). Their Nd isotopic composition reveals that the T-depleted mantle (DM) model ages of the samples are highly variable and range from 2867 Ma to 4015 Ma.

  2. Impeding 99Tc(IV) mobility in novel waste forms

    Science.gov (United States)

    Lee, Mal-Soon; Um, Wooyong; Wang, Guohui; Kruger, Albert A.; Lukens, Wayne W.; Rousseau, Roger; Glezakou, Vassiliki-Alexandra

    2016-06-01

    Technetium (99Tc) is an abundant, long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state. Tc immobilization is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels has been proposed as a novel method to increase Tc retention in glass waste forms during vitrification. However, experiments under high-temperature and oxic conditions show reoxidation of Tc(IV) to volatile pertechnetate, Tc(VII). Here we examine this problem with ab initio molecular dynamics simulations and propose that, at elevated temperatures, doping with first row transition metal can significantly enhance Tc retention in magnetite in the order Co>Zn>Ni. Experiments with doped spinels at 700 °C provide quantitative confirmation of the theoretical predictions in the same order. This work highlights the power of modern, state-of-the-art simulations to provide essential insights and generate theory-inspired design criteria of complex materials at elevated temperatures.

  3. Solubility control of technetium release from Saltstone by TcO{sub 2}·xH{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J., E-mail: kirk.cantrell@pnnl.gov [Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K6-81, Richland, WA 99352 (United States); Williams, Benjamin D. [Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K6-81, Richland, WA 99352 (United States)

    2013-06-15

    Saltstone leaching experiments were conducted using a modified single-pass flow-through method under anoxic conditions. The analytical results of leachates collected from these experiments were evaluated using thermodynamic modeling to determine if the data were consistent with potential solubility controlling phases. The results demonstrate that technetium release from Saltstone under anoxic conditions is controlled by the solubility of TcO{sub 2}·xH{sub 2}O (likely TcO{sub 2}·1.6H{sub 2}O). In our system the solubility of TcO{sub 2}·1.6H{sub 2}O appears to have been reached equilibrium within 2 weeks, with a Tc concentration of approximately 1.5 × 10{sup −6} M. Because Saltstone is a cementitious material, it is a continuously reacting solid with component phases that continue to change over very long time periods (up to hundreds of years). As a result of this process, the concentrations of technetium in equilibrium with TcO{sub 2}·1.6H{sub 2}O are likely to vary as the composition of Saltstone pore fluid evolves over time. In a disposal scenario where the initially high pH values (∼12.5–13) decrease (due to carbonation over very long time periods), the solubility of TcO{sub 2}·xH{sub 2}O would decrease significantly. The thermodynamic data used to determine the solubility of TcO{sub 2}·1.6H{sub 2}O were taken from the tabulation of critically selected thermodynamic data determined by the Nuclear Energy Agency. Solid phase characterization to demonstrate the presence of TcO{sub 2}·xH{sub 2}O was not possible due to the low concentrations of technetium in our samples. Previous solid phase characterization studies with cementitious waste forms that were very similar to our Saltstone samples as well as reaction products derived from reductive immobilization of TcO{sub 4}{sup -} by amorphous FeS clearly indicate the presence of TcO{sub 2} with varying degrees of hydration. Although, the presence of TcS{sub x} or other reduced technetium sulfide phases

  4. Initial direct comparison of 99mTc-TOC and 99mTc-TATE in identifying sites of disease in patients with proven GEP NETs.

    Science.gov (United States)

    Cwikla, Jaroslaw B; Mikolajczak, Renata; Pawlak, Dariusz; Buscombe, John R; Nasierowska-Guttmejer, Anna; Bator, Andrzej; Maecke, Helmut R; Walecki, Jerzy

    2008-07-01

    The imaging of neuroendocrine tumors has become one of the most significant areas in nuclear oncology. In an attempt to provide high-quality imaging and possible sensitivity at a reduced cost, time, and radiation dose, several (99m)Tc agents have been proposed. The aim of this initial study was to compare the tumor uptake and biodistribution of 2 new 6-hydrazinopyridine-3-carboxylic acid (HYNIC)-derivatized Tyr(3)-octreotide analogs, (99m)Tc-[HYNIC,Tyr(3)]octreotide ((99m)Tc-TOC) and (99m)Tc-[HYNIC,Tyr(3),Thr(8)]octreotide ((99m)Tc-TATE), in patients with somatostatin receptor-expressing tumors. Each of 12 patients with proven gastrointestinal pancreatic neuroendocrine tumors received a mean activity of 520 MBq of (99m)Tc-TOC and (99m)Tc-TATE. Scintigraphy with both tracers was performed 3-4 h after their injection using standard whole-body and SPECT imaging. The images were reviewed subjectively by 2 readers, who reported tumor uptake lesion by lesion. Both radiotracers demonstrated concordance between the results in 7 patients (58%). In total, 110 sites of disease were identified with (99m)Tc-TOC, compared with 115 with (99m)Tc-TATE. There was 1 case in which (99m)Tc-TOC identified sites of disease not seen on (99m)Tc-TATE imaging but 4 cases in which some sites of disease were seen with (99m)Tc-TATE and not (99m)Tc-TOC. In this initial study, both tracers seem to show similar sites of tumor, with (99m)Tc-TATE having a slight edge in the total number of lesions seen, especially in lymph node metastases.

  5. Improving thermal insulation of TC4 using YSZ-based coating and SiO2 aerogel

    Directory of Open Access Journals (Sweden)

    Lei Jin

    2015-04-01

    Full Text Available In this paper, air plasmas spray (APS was used to prepare YSZ and Sc2O3–YSZ (ScYSZ coating in order to improve the thermal insulation ability of TC4 alloy. SiO2 aerogel was also synthesized and affixed on TC4 titanium alloy to inhabit thermal flow. The microstructures, phase compositions and thermal insulation performance of three coatings were analyzed in detail. The results of thermal diffusivity test by a laser flash method showed that the thermal diffusivities of YSZ, Sc2O3–YSZ and SiO2 aerogel are 0.553, 0.539 and 0.2097×10−6 m2/s, respectively. Then, the thermal insulation performances of three kinds of coating were investigated from 20 °C to 400 °C using high infrared radiation heat flux technology. The experimental results indicated that the corresponding temperature difference between the top TC4 alloy (400 °C and the bottom surface of YSZ is 41.5 °C for 0.6 mm thickness coating. For 1 mm thickness coating, the corresponding temperature difference between the top TC4 alloys (400 °C and the bottom surface of YSZ, ScYSZ, SiO2 aerogel three specimens is 54, 54.6 and 208 °C, respectively. The coating thickness and species were found to influence the heat insulation ability. In these materials, YSZ and ScYSZ exhibited a little difference for heat insulation behavior. However, SiO2 aerogel was the best one among them and it can be taken as protection material on TC4 alloys. In outer space, SiO2 aerogel can meet the need of thermal insulation of TC4 of high-speed aircraft.

  6. Demonstration of capabilities of high temperature composites analyzer code HITCAN

    Science.gov (United States)

    Singhal, Surendra N.; Lackney, Joseph J.; Chamis, Christos C.; Murthy, Pappu L. N.

    1990-01-01

    The capabilities a high temperature composites analyzer code, HITCAN which predicts global structural and local stress-strain response of multilayered metal matrix composite structures, are demonstrated. The response can be determined both at the constituent (fiber, matrix, and interphase) and the structure level and includes the fabrication process effects. The thermo-mechanical properties of the constituents are considered to be nonlinearly dependent on several parameters including temperature, stress, and stress rate. The computational procedure employs an incremental iterative nonlinear approach utilizing a multifactor-interactive constituent material behavior model. Various features of the code are demonstrated through example problems for typical structures.

  7. Response of polymer composites to high and low velocity impact

    Science.gov (United States)

    Hsieh, C. Y.; Mount, A.; Jang, B. Z.; Zee, R. H.

    1990-01-01

    The present investigation of fiber-reinforced polymer matrix composites' impact characteristics employed a drop tower for the low-velocity impact case and a novel, projectile instantaneous velocity-measuring sensor for high-velocity impact. Attention was given to the energy loss of projectiles in composites reinforced with polyethylene, kevlar, and graphite. Two distinct energy-loss mechanisms are noted, the first of which is due to the actual fracture process while the other is due to the generation of friction heat. The drop-tower impact-test results furnish the strain-rate dependence of the energy loss.

  8. Asialoglycoprotein receptor targeted imaging using Tc-99m galactosylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E. M.; Jeong, H. J.; Kim, B. C.; Kim, C. K [Wonkang University College of Medicine, Iksan (Korea, Republic of)

    2004-07-01

    The asialoglycoprotein receptor (ASGP-R) is expressed on liver hepatocytes. Chitosan conjugates of galactose have shown to be specifically taken up by liver parenchymal cells via ASGP-R. In this study, Tc-99m hydrazino nicotinamide (HYNIC)-galactosylated chitosan (HYNIC-GC) was synthesized and evaluated as a targeted agent for the imaging of hepatocytes. GC was obtained after coupling of lactobionic acid as the galactose moiety and coupled with HYNIC. HYNIC-GC was radiolabeled with Tc-99m using stannous chloride and tricine as reducing agent and coligand respectively. Hepatic uptake property of Tc-99m HYNIC-GC was studied in female Balb/C mouse. Tc-99m HYNIC--GC and Tc-99m HYNIC-Chitosan as a control were intravenously injected into mice. Receptor binding was identified by coinjection with 50 mM and 80mM free galactose respectively. Biodistribution was determined at three different time points. The level of galactose substitution was 7.6%. Labeling efficiency was >90% both in vitro and serum up to 24 h. Tc-99m HYNIC-GC injected via tail vein of mice showed high selectivity of liver. On the other hands, Tc-99m HC without galactose group showed low uptake (Fig. 1A, 1B). Hepatic uptake of Tc-99m HYNIC-GC was dramatically blocked by 50 mM and 80 mM free galactose coinjection (Fig. 1C, 1D). The liver accumulated about 14 percent injected dose per gram (%ID/g) up to 120 min after injection. Tc-99m HYNIC-GC showed specific and rapid targeting to liver. It is a promising specific radiopharmaceutical with potential applications in the imaging of liver parenchymal cells.

  9. GASIFICATION TEST RUN TC06

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services, Inc.

    2003-08-01

    This report discusses test campaign TC06 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC06. Test run TC06 was started on July 4, 2001, and completed on September 24, 2001, with an interruption in service between July 25, 2001, and August 19, 2001, due to a filter element failure in the PCD caused by abnormal operating conditions while tuning the main air compressor. The reactor temperature was varied between 1,725 and 1,825 F at pressures from 190 to 230 psig. In TC06, 1,214 hours of solid circulation and 1,025 hours of coal feed were attained with 797 hours of coal feed after the filter element failure. Both reactor and PCD operations were stable during the test run with a stable baseline pressure drop. Due to its length and stability, the TC06 test run provided valuable data necessary to analyze long-term reactor operations and to identify necessary modifications to improve equipment and process performance as well as progressing the goal of many thousands of hours of filter element exposure.

  10. Low and high velocity impact response of thick hybrid composites

    Science.gov (United States)

    Hiel, Clement; Ishai, Ori

    1993-01-01

    The effects of low and high velocity impact on thick hybrid composites (THC's) were experimentally compared. Test Beams consisted of CFRP skins which were bonded onto an interleaved syntactic foam core and cured at 177 C (350 F). The impactor tip for both cases was a 16 mm (0.625 inch) steel hemisphere. In spite of the order of magnitude difference in velocity ranges and impactor weights, similar relationships between impact energy, damage size, and residual strength were found. The dependence of the skin compressive strength on damage size agree well with analytical open hole models for composite laminates and may enable the prediction of ultimate performance for the damaged composite, based on visual inspection.

  11. The Rise of Tc: A Promising Paradigm via Interfacial Mechanism

    Science.gov (United States)

    Chu, C. W.; Lv, B.; Deng, L. Z.; Lorenz, B.; Jawdat, B.; Gooch, M.; Shrestha, K.; Zhao, K.; Zhu, X. Y.; Xue, Y. Y.; Wei, F. Y.

    2013-07-01

    Following the seminal detection of superconductivity at 35 K in the first cuprate high temperature superconductor Ba-doped ternary LCO (La214) by Mueller and Bednorz in 1986, the discovery of the first liquid nitrogen superconductor quaternary YBCO (Y123) with a transition temperature Tc of 93 K by Chu, Wu, and colleagues in 1987 has ushered in the modern era of high temperature superconductivity (HTS). In the ensuing 25 years, great progress has been made in all areas of HTS research and development, from materials to physics to devices. However, the Tc remains at 134 K in quaternary HBCCO (Hg1223) at ambient pressure achieved in 1993 by Schilling et al. and at 164 K in the same compound under high pressure in the same year by Gao et al. A holistic multidisciplinary enlightened empirical approach has been proposed to search for superconductors with higher Tc, which includes the discovery of new compounds empirically and the realization of novel mechanisms proposed by theorists. Recently, we have observed nonbulk superconductivity in single crystalline rare-earth doped Ca122 samples with an onset Tc of 49 K, higher than the Tc of any known compounds formed of the constituent elements at ambient or under high pressures. Subsequent systematic structural, electrical, magnetic, and calorimetric investigations suggest that the observation may be attributed to an interface-induced Tc, thus suggesting a possible new paradigm for higher Tc. In this presentation, our results will be presented and discussed, following a brief recollection of a few events in our lab in the continuing search for higher Tc, even though a number of review articles have appeared.

  12. Enhanced 99 Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Luksic, Steven A.; Wang, Guohui; Saslow, Sarah; Kim, Dong-Sang; Schweiger, Michael J.; Soderquist, Chuck Z.; Bowden, Mark E.; Lukens, Wayne W.; Kruger, Albert A.

    2017-11-01

    Technetium (99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals. Two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 – 1,000 oC. After being cooled, the solid glass specimens prepared at different temperatures were analyzed for Tc oxidation state using Tc K-edge XANES. In most samples, Tc was partially oxidized from Tc(IV) to Tc(VII) as the melt temperature increased. However, Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were moderately higher than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.

  13. High Performance Thin-Film Composite Forward Osmosis Membrane

    KAUST Repository

    Yip, Ngai Yin

    2010-05-15

    Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 μm) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m2-h-1, while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution. © 2010 American Chemical Society.

  14. Composite flywheel material design for high-speed energy storage

    Directory of Open Access Journals (Sweden)

    Michael A. Conteh

    2016-06-01

    Full Text Available Lamina and laminate mechanical properties of materials suitable for flywheel high-speed energy storage were investigated. Low density, low modulus and high strength composite material properties were implemented for the constant stress portion of the flywheel while higher density, higher modulus and strength were implemented for the constant thickness portion of the flywheel. Design and stress analysis were used to determine the maximum energy densities and shape factors for the flywheel. Analytical studies along with the use of the CADEC-online software were used to evaluate the lamina and laminate properties. This study found that a hybrid composite of M46J/epoxy–T1000G/epoxy for the flywheel exhibits a higher energy density when compared to known existing flywheel hybrid composite materials such as boron/epoxy–graphite/epoxy. Results from this study will contribute to further development of the flywheel that has recently re-emerged as a promising application for energy storage due to significant improvements in composite materials and technology.

  15. Spectroscopic Properties of Tc(I) Tricarbonyl Species Relevant to the Hanford Tank Waste

    Energy Technology Data Exchange (ETDEWEB)

    Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Andersen, Amity [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Washton, Nancy M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-04

    Technetium-99 (Tc) exists predominately in soluble forms in the liquid supernatant and salt cake fractions of the nuclear tank waste stored at the U.S. DOE Hanford Site. In the strongly alkaline environments prevalent in the tank waste, its dominant chemical form is pertechnetate (TcO4-, oxidation state +7). However, attempts to remove Tc from the Hanford tank waste using ion-exchange processes specific to TcO4- only met with limited success, particularly processing tank waste samples containing elevated concentrations of organic complexants. This suggests that a significant fraction of the soluble Tc can be present as non-pertechnetate low-valent Tc (oxidation state < +7) (non-pertechnetate). The chemical identities of these non-pertechnetate species are poorly understood. Previous analysis of the SY-101 and SY-103 tank waste samples provided strong evidence that non-pertechnetate can be comprised of [Tc(CO)3]+ complexes containing Tc in oxidation state +1 (Lukens et al. 2004). During the last two years, our team has expanded this work and demonstrated that high-ionic-strength solutions typifying tank waste supernatants promote oxidative stability of the [Tc(CO)3]+ species (Rapko et al. 2013; Levitskaia et al. 2014). It also was observed that high-ionic-strength alkaline matrices stabilize Tc(VI) and potentially Tc(IV) oxidation states, particularly in presence organic chelators, suggesting that the relevant Tc compounds can serve as important redox intermediates facilitating the reduction of Tc(VII) to Tc(I). Designing strategies for effective Tc processing, including separation and immobilization, necessitates understanding the molecular structure of these non-pertechnetate species and their identification in the actual tank waste samples. To-date, only limited information exists regarding the nature and characterization of the Tc(I), Tc(IV), and Tc(VI) species. One objective of this project is to

  16. Concurrent Probabilistic Simulation of High Temperature Composite Structural Response

    Science.gov (United States)

    Abdi, Frank

    1996-01-01

    A computational structural/material analysis and design tool which would meet industry's future demand for expedience and reduced cost is presented. This unique software 'GENOA' is dedicated to parallel and high speed analysis to perform probabilistic evaluation of high temperature composite response of aerospace systems. The development is based on detailed integration and modification of diverse fields of specialized analysis techniques and mathematical models to combine their latest innovative capabilities into a commercially viable software package. The technique is specifically designed to exploit the availability of processors to perform computationally intense probabilistic analysis assessing uncertainties in structural reliability analysis and composite micromechanics. The primary objectives which were achieved in performing the development were: (1) Utilization of the power of parallel processing and static/dynamic load balancing optimization to make the complex simulation of structure, material and processing of high temperature composite affordable; (2) Computational integration and synchronization of probabilistic mathematics, structural/material mechanics and parallel computing; (3) Implementation of an innovative multi-level domain decomposition technique to identify the inherent parallelism, and increasing convergence rates through high- and low-level processor assignment; (4) Creating the framework for Portable Paralleled architecture for the machine independent Multi Instruction Multi Data, (MIMD), Single Instruction Multi Data (SIMD), hybrid and distributed workstation type of computers; and (5) Market evaluation. The results of Phase-2 effort provides a good basis for continuation and warrants Phase-3 government, and industry partnership.

  17. Mechanical Properties of Composites Used in High-Voltage Applications

    Directory of Open Access Journals (Sweden)

    Andreas Moser

    2016-07-01

    Full Text Available Materials used in high voltage applications have to meet a lot of regulations for their safety and functional usage during their lifetime. For high voltage applications the electrical properties are the most relevant designing criteria. However, the mechanical properties of such materials have rarely been considered for application dimensioning over the last decades. This article gives an overview of composite materials used in high voltage applications and some basic mechanical and thermo-mechanical characterization methods of such materials, including a discussion of influences on practically used epoxy based thermosets.

  18. Comparative biological evaluation between {sup 99m}Tc tricarbonyl and {sup 99m}Tc-Sn(II) levosalbutamol as a β{sub 2}-adrenoceptor agonist

    Energy Technology Data Exchange (ETDEWEB)

    Sanad, Mahmoud H. [Atomic Energy Authority, Cairo (Egypt). Labeled Compounds Dept.; Borai, Emad H. [Atomic Energy Authority, Cairo (Egypt). Analytical Chemistry Dept.

    2015-07-01

    This study describes the comparison between {sup 99m}Tc-tricarbonyl and {sup 99m}Tc-Sn (II) levosalbutamol as a β{sub 2}-adrenoceptors radiopharmaceutical and evaluation of their different biological characteristics using experimental animals. Levosalbutamol was labeled firstly with {sup 99m}Tc in the presence of SnCl{sub 2} . 2H{sub 2}O as a reducing agent under the optimum conditions: pH 8, 50 μg SnCl{sub 2} . 2H{sub 2}O, room temperature, 40 μg levosalbutamol and 30 min reaction time to give a maximum radiochemical yield of 98 ± 0.1%. The obtained {sup 99m}Tc-levosalbutamol was stable for a time up to 8 h. Secondly, {sup 99m}Tc-tricarbonyl ([{sup 99m}Tc(CO){sub 3}(H{sub 2}O){sub 3}]{sup +}) levosalbutamol was prepare under 30 min heating at 100 C. Labeling yield and stability were analyzed by high performance liquid chromatography (labeling yield >99% and stability for 8 h). Biodistribution investigation showed that, the maximum uptake ratio of the {sup 99m}Tc-levosalbutamol ({sup 99m}Tc-Lev) between lung and heart was 2.34 ± 0.62 % of the injected activity/g tissue organ, at 30 min post-injection. But in case of {sup 99m}Tc-tricarbonyl levosalbutamol ({sup 99m}Tc-tricarbonyl Lev) the maximum uptake ratio was 3.6 ± 0.11 of the injected activity/g tissue organ, at 30 min post-injection. This indicates that {sup 99m}Tc-tricarbonyl levosalbutamol was more selective for lung β{sub 2}-adrenoceptors than {sup 99m}Tc-levosalbutamol. These results introduce {sup 99m}Tc-tricarbonyl levosalbutamol as a novel potential radiopharmaceutical for lung imaging.

  19. Availability of {sup 99}Tc in undisturbed soil cores

    Energy Technology Data Exchange (ETDEWEB)

    Denys, Sebastien; Echevarria, Guillaume E-mail: guillaume.echevarria@ensaia.inpl-nancy.fr; Florentin, Louis; Leclerc-Cessac, Elisabeth; Morel, Jean-Louis

    2003-07-01

    Models for safety assessment of radioactive waste repositories need accurate values of the soil-to-plant transfer of radionuclides. In oxidizing environments, {sup 99}Tc is expected to occur as pertechnetate ({sup 99}TcO{sub 4}{sup -}). Due to its high mobility, leaching of this element in the field might be important, potentially affecting the reliability of estimated transfer parameters of {sup 99}Tc as measured in closed experimental systems such as hydroponics or pot experiments. The aim of this experiment was to measure the leaching of {sup 99}Tc in undisturbed irrigated soil cores under cultivation as well as plant uptake and to study the possible competition between the two transfer pathways. Undisturbed soil cores (50x50 cm) were sampled from a Rendzic Leptosol (R), a colluvial Fluvic Cambisol (F) and a Dystric Cambisol (D) using PVC tubes (three cores sampled per soil type). Each core was equipped with a leachate collector at the bottom, allowing the monitoring of {sup 99}Tc leaching through the cores. Cores were placed in a greenhouse and maize (Zea mays L., cv. DEA, Pioneer[reg]) was sown. After 135 d, maize was harvested and radioactivity determined in both plant and water samples. Results showed that during the growing period, leaching of {sup 99}Tc was limited, due to the high evapotranspiration rate of maize. After harvest, leaching of {sup 99}Tc went on because of the absence of evapotranspiration. Effective uptake (EU) of {sup 99}Tc in leaves and grains was calculated. EU reached 70% of the input in the leaves and was not significantly different among soils. These results confirmed those obtained from pot experiments, even though leaching was allowed to occur in close-to-reality hydraulical conditions. As a consequence, it was concluded that pot experiments are an adequate surrogate for more complex 'close-to-reality' experimental systems for measuring transfer factors.

  20. Uncovering and Validating Toughening Mechanisms in High Performance Composites

    Science.gov (United States)

    2015-09-17

    start [Patek, S.N., Korff, W.L. & Caldwell, R.L. Biomechanics : Deadly strike mechanism of a mantis shrimp - This shrimp packs a punch powerful enough to...also be applied to man-made composites. Possible applications are found in helmets for sports and military protection. Since the duration of the...Biomaterials, Biomechanics and Regenerative Medicine, RutaN, Medellin, Colombia, May 16, 2014. "Numerical Investigation of Naturally-Occurring High

  1. Characterization of high-pressure RTM processes for manufacturing of high performance composites

    OpenAIRE

    R. Chaudhari; Karcher, M.; Elsner, P.; Henning, F

    2012-01-01

    The current paper addresses new variants of the RTM process namely High Pressure-Injection Resin Transfer Molding (HP-IRTM) and High Pressure - Compression Resin Transfer Molding (HP-CRTM) for manufacturing of continuous fiber reinforced composites with high fiber volume content. Both these process utilize High Pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The objective of the proposed study was to...

  2. Structure recognition from high resolution images of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela; Perciano, Talita; Krishnan, Harinarayan; Loring, Burlen; Bale, Hrishikesh; Parkinson, Dilworth; Sethian, James

    2015-01-05

    Fibers provide exceptional strength-to-weight ratio capabilities when woven into ceramic composites, transforming them into materials with exceptional resistance to high temperature, and high strength combined with improved fracture toughness. Microcracks are inevitable when the material is under strain, which can be imaged using synchrotron X-ray computed micro-tomography (mu-CT) for assessment of material mechanical toughness variation. An important part of this analysis is to recognize fibrillar features. This paper presents algorithms for detecting and quantifying composite cracks and fiber breaks from high-resolution image stacks. First, we propose recognition algorithms to identify the different structures of the composite, including matrix cracks and fibers breaks. Second, we introduce our package F3D for fast filtering of large 3D imagery, implemented in OpenCL to take advantage of graphic cards. Results show that our algorithms automatically identify micro-damage and that the GPU-based implementation introduced here takes minutes, being 17x faster than similar tools on a typical image file.

  3. High temperature deformation behaviour of particulate reinforced aluminium composites

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyuk Chon; Yoon, Eui Pak [Hanyang Univ., Seoul (Korea, Republic of)

    1995-10-01

    The hot deformation behaviour of particulate reinforced aluminium 6061 Al composite were investigated by hot compression tests in the temperature range from 623 K to 823 K with strain rate of 10{sup -3} {approx} 5.0 S{sup -1}. The effect of reinforced particulate volume fraction, mean diameter on the high temperature flow stress has also been studied. Experimental results showed that the increase in the volume fraction of reinforcement contributed to the rising of yield stress, but the stress above the yield point appeared to be steady at all volume fractions. The apparent activation energy for deformation was 290 kJ/mol for un reinforced 6061 Al, 327 kJ/mol for 6061 Al-20 vol.% SiC composite and 531 kJ/mol for 6061 Al-20 vol.% Al{sub 2}0{sub 3} composite. It appeared that Al{sub 2}0{sub 3} reinforced composites was more difficult to hot deform. (author). 21 refs., 9 figs., 3 tab.

  4. Low melting high lithia glass compositions and methods

    Science.gov (United States)

    Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

    2000-01-01

    The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

  5. Effect of particle size and particle size distribution on physical characteristics, morphology and crystal strucutre of explosively compacted high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kotsis, I.; Enisz, M.; Oravetz, D. [Univ. of Veszprem (Hungary)] [and others

    1994-12-31

    A superconductor, of composition Y(Ba,K,Na){sub 2}Cu{sub 3}O{sub x}/F{sub y} and a composite, of composition Y(Ba,K,Na){sub 2}Cu{sub 3}O{sub x}/F{sub y}+Ag, with changing K, Na and F content, but a constant silver content (Ag=10 mass per cent) was prepared using a single heat treatment. The resulting material was ground in a corundum lined mill, separated to particle size fractions of 0-40 {mu}m, 0-63 {mu}m and 63-900 {mu}m and explosively compacted, using an explosive pressure of 10{sup 4} MPa and a subsequent heat treatment. Best results were obtained with the 63-900 {mu}m fraction of composition Y(Ba{sub 1,95}K{sub 0,01})Cu{sub 3}O{sub x}F{sub 0,05}/Ag: porosity <0.01 cm{sup 3}/g and current density 2800 A/cm{sup 2} at 77 K.

  6. The Dynamic Mechanical Analysis of Highly Filled Rice Husk Biochar/High-Density Polyethylene Composites

    Directory of Open Access Journals (Sweden)

    Qingfa Zhang

    2017-11-01

    Full Text Available In this study, rice husk biochar/high-density polyethylene (HDPE composites were prepared via melt mixing followed by extrusion. Effects of biochar content and testing temperature on the dynamic mechanical analysis (DMA of the composites were studied. Morphological analysis of the rice husk biochar and composites were evaluated by scanning electron microscopy (SEM. The results showed that biochar had a positive effect on dynamic viscoelasticity, creep resistance and stress relaxation properties of the composites, but the creep resistance and stress relaxation of the composites decreased with the increase of temperature. SEM analysis showed that HDPE components were embedded in the holes of the rice husk biochar, and it is believed that strong interaction was achieved.

  7. Implementation Challenges for Ceramic Matrix Composites in High Temperature Applications

    Science.gov (United States)

    Singh, Mrityunjay

    2004-01-01

    Ceramic matrix composites are leading candidate materials for a number of applications in aeronautics, space, energy, electronics, nuclear, and transportation industries. In the aeronautics and space exploration systems, these materials are being considered for applications in hot sections of jet engines such as the combustor liner, nozzle components, nose cones, leading edges of reentry vehicles and space propulsion components. Applications in the energy and environmental industries include radiant heater tubes, heat exchangers, heat recuperators, gas and diesel particulate filters (DPFs), and components for land based turbines for power generation. These materials are also being considered for use in the first wall and blanket components of fusion reactors. There are a number of critical issues and challenges related to successful implementation of composite materials. Fabrication of net and complex shape components with high density and tailorable matrix properties is quite expensive, and even then various desirable properties are not achievable. In this presentation, microstructure and thermomechanical properties of composites fabricated by two techniques (chemical vapor infiltration and melt infiltration), will be presented. In addition, critical need for robust joining and assembly technologies in successful implementation of these systems will be discussed. Other implementation issues will be discussed along with advantages and benefits of using these materials for various components in high temperature applications.

  8. Studies on Automated Manufacturing of High Performance Composites

    Science.gov (United States)

    Cano, R. J.; Belvin, H. L.; Hulcher, A. B.; Grenoble, R. W.

    2001-01-01

    The NASA Langley Research Center fiber placement facility has proven to be a valuable asset for obtaining data, experience, and insights into the automated fabrication of high performance composites. The facility consists of two automated devices: an Asea Brown Boveri (ABB) robotic arm with a modified heated head capable of hot gas and focused infrared heating and a 7' x 17' gantry containing a feeder head, rotating platform, focused infrared lamp and e-beam gun. While uncured thermoset tow and tape, e.g., epoxy and cyanate prepreg, can be placed with a robot, the placement facility s most powerful attribute is the ability to place thermoplastic and e-beam curable material to net shape. In recent years, ribbonizing techniques have been developed to make high quality thermoplastic and thermoset dry material forms to the standards required for robotic placement. A variety of composites have been fabricated from these ribbons by heated head tow and tape placement including both flat plates and cylinders. Composite mechanical property values of the former were between 85 and 100 percent of those obtained by hand lay-up/autoclave processing.

  9. High-cycle fatigue strength of a pultruded composite material

    Directory of Open Access Journals (Sweden)

    L. Vergani

    2009-01-01

    Full Text Available Dealing with composites in polymeric matrix, the pultruded ones are among the more suitable for large production rates and volumes. For this reason, their use is increasing also in structural applications in civil and mechanical engineering. However, their use is still limited by the partial knowledge of their fatigue behaviour; in many applications it is, indeed, required a duration of many millions of cycles, while most of the data that can be found in literature refer to a maximum number of cycles equal to 3 millions. In this paper a pultruded composite used for manufacturing structural beams is considered and its mechanical behaviour characterized by means of static and high-cycle fatigue tests. The results allowed to determine the S-N curve of the material and to assess the existence of a fatigue limit. Observations at the scanning electronic microscope (SEM allowed to evaluate the damage mechanisms involved in the static and fatigue failure of the material.

  10. Ti-Al Composite Wires with High Specific Strength

    Directory of Open Access Journals (Sweden)

    Ludwig Schultz

    2011-11-01

    Full Text Available An alternative deformation technique was applied to a composite made of titanium and an aluminium alloy in order to achieve severe plastic deformation. This involves accumulative swaging and bundling. Furthermore, it allows uniform deformation of a composite material while producing a wire which can be further used easily. Detailed analysis concerning the control of the deformation process, mesostructural and microstructural features and tensile testing was carried out on the as produced wires. A strong grain refinement to a grain size of 250–500 nm accompanied by a decrease in 〈111〉 fibre texture component and a change from low angle to high angle grain boundary characteristics is observed in the Al alloy. A strong increase in the mechanical properties in terms of ultimate tensile strength ranging from 600 to 930 MPa being equivalent to a specific strength of up to 223 MPa/g/cm3 was achieved.

  11. High performance hydrophilic pervaporation composite membranes for water desalination

    KAUST Repository

    Liang, Bin

    2014-08-01

    A three-layer thin film nanofibrous pervaporation composite (TFNPVC) membrane was prepared by sequential deposition using electrospraying/electrospinning. The poly(vinyl alcohol) (PVA) top barrier layer was first electrosprayed on aluminum foil and its thickness can be easily controlled by adjusting the collecting time. Next a polyacrylonitrile (PAN) nanofibrous scaffold was deposited by electrospinning as a mid-layer support. A nonwoven PET layer is used to complete the composite membrane. The pervaporation desalination performance of TFNPVC membranes was tested using NaCl solutions at 100. Pa and at room temperature. The TFNPVC membranes show excellent desalination performance (high water flux and salt rejection >. 99.5%) for different salt concentrations with virtually no change in performance after 50. h of operation. © 2014 Elsevier B.V.

  12. The Impact of Virgin Coconut Oil and High-Oleic Safflower Oil on Body Composition, Lipids, and Inflammatory Markers in Postmenopausal Women.

    Science.gov (United States)

    Harris, Margaret; Hutchins, Andrea; Fryda, Lisa

    2017-04-01

    This randomized crossover study compared the impact of virgin coconut oil (VCO) to safflower oil (SO) on body composition and cardiovascular risk factors. Twelve postmenopausal women (58.8 ± 3.7 year) consumed 30 mL VCO or SO for 28 days, with a 28-day washout. Anthropometrics included body weight and hip and waist circumference. Fat percent for total body, android and gynoid, fat mass, and lean mass were measured using dual-energy X-ray absorptiometry. Women maintained their typical diet recording 28 days of food records during the study. Results were analyzed with SPSS v24 with significance at P ≤ .05. Comparisons are reported as paired t-test since no intervention sequence effect was observed. VCO significantly raised total cholesterol, TC (+18.2 ± 22.8 mg/dL), low-density lipoprotein (+13.5 ± 16.0 mg/dL), and high-density lipoprotein, HDL (+6.6 ± 7.5 mg/dL). SO did not significantly change lipid values. TC and HDL were significantly different between test oils. The TC/HDL ratio change showed a neutral effect of both VCO and SO. One person had adverse reactions to VCO and increased inflammation. VCO decreased IL-1β for each person who had a detected sample. The impact of VCO and SO on other cytokines varied on an individual basis. This was the first study evaluating the impact of VCO on body composition in Caucasian postmenopausal women living in the United States. Results are suggestive that individuals wishing to use coconut oil in their diets can do so safely, but more studies need to be conducted with larger sample sizes, diverse populations, and more specific clinical markers such as particle size.

  13. Transient Response of Different Highly Conductive PCM Composites

    Science.gov (United States)

    Mahmoud Alhamdo, Mohammed H.; Bdaiwi, Bashar A.; Hasan, Ali H.

    In this work, the thermal conductivity of paraffin wax has been enhanced by employing four different high conductivity additives infiltrated within the PCM. These include the use of Graphite Powder (GP), Copper Particles (CP), Aluminum oxide Particles (AP), and Copper Network (CN). Four different types of pure waxes were selected, tested and compared. Twelve samples of wax/additives composites were prepared by adding different mass ratios of 3, 6 and 9 % of additives by weight in each type of wax. The storage system contains spherical capsules filled with composite PCMs that are packed in an insulated cylindrical storage. Transient temperature based governing equations have been developed and solved numerically by both ANSYS FLUENT 14 code and by numerical implicit time marching model. With progress of time, results showed that the numerical predictions of ANSYS software start to deviate from the experimental observations. The grade-B paraffin was found to be the best one. Results indicate that all the enhancement methods have significant effect on the thermal response of the system. However, the utilization of 6 % additives by weight has been found to provide the best enhancement effect. The developed new-sort CN composite is found to produce the best thermal response due to its good homogeneity with wax and its high conductivity. Results showed that for CN composite with 6 % additives, the charging and discharging time decreased by 26.4 and 30.3 % respectively than that of pure wax and the thermal conductivity enhanced by 2.57 times that of pure wax.

  14. Power Systems Development Facility Gasification Test Campaign TC25

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-12-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

  15. A correlative study between {sup 99m}Tc-ESTCPTA and {sup 99m}Tc-MIBI in rats

    Energy Technology Data Exchange (ETDEWEB)

    Unak, Perihan E-mail: unak@bornova.ege.edu.tr; Enginar, Huseyin; Zuemruet Biber, F.; Yurt Lambrecht, Fatma; Aslani, M.A.A.; Ozkilic, Hayal

    2002-11-01

    Tissue distribution of the {sup 99m}Tc labeled derivative of the estrogen compound 3,17-{alpha}-estradiolyl propyl 1,4,8,11-tetraazacyclotetradecanyl-1-(4-methylbenzoic acid) ester (ESTCPTA), which has an 3,17-{alpha}-estradiolyl propinol coupled to 1-(4-methylbenzoic acid)1,4,8,11-tetraazacyclotetradecane (CPTA), was compared to {sup 99m}Tc-MIBI (methoxyisobutyl isonitrile) in female Albino Wistar rats. Tissues of interest included lung, liver, heart, kidneys, spleen, stomach, intestines, pancreas, muscle, blood, breast, ovary, fat, and uterus. {sup 99m}Tc-ESTCPTA uptake by the uterus and ovary, as ER-rich tissues, was highly selective. Maximum uptakes for {sup 99m}Tc-MIBI and {sup 99m}Tc-ESTCPTA are 90 min in breast, ovary and uterus. The pancreas also showed significant receptor saturated and unsaturated ratios for {sup 99m}Tc-ESTCPTA. Results are sufficiently encouraging to generate further evaluation of these and related compounds as possible estrogen receptor based tumor imaging and therapeutic agents in estrogen-rich tissues.

  16. Weak bond detection in composites using highly nonlinear solitary waves

    Science.gov (United States)

    Singhal, Taru; Kim, Eunho; Kim, Tae-Yeon; Yang, Jinkyu

    2017-05-01

    We experimentally investigate a diagnostic technique for identifying a weak bond in composites using highly nonlinear solitary waves (HNSWs). We set up a one-dimensional chain of granular crystals, consisting of spherical particles with nonlinear interactions, to generate HNSWs. These solitary wave packets are transmitted into an inspection area of composites by making a direct contact with the chain. We demonstrate that a strong type of solitary waves injected to the weak bond area can break the weak bond of laminates, thereby causing delamination. Then, to identify the creation of the delamination, we transmit a weak type of solitary waves by employing the same apparatus, and measure the solitary waves reflected from the specimens. By analyzing these reflected solitary waves, we differentiate the weak bond samples with the pristine bond ones in an efficient and fast manner. The diagnostic results based on the proposed method are compared with the strength and energy release rate at bond interfaces, which are measured via standard testing methods such as three point bending and end notched flexure tests. This study shows the potential of solitary wave-based detection of weak bonds for hot spot monitoring of composite-based structures.

  17. Highly Conductive Polypropylene-Graphene Nonwoven Composite via Interface Engineering.

    Science.gov (United States)

    Pan, Qin; Shim, Eunkyoung; Pourdeyhimi, Behnam; Gao, Wei

    2017-08-01

    Here we report a highly conductive polypropylene-graphene nonwoven composite via direct coating of melt blown polypropylene (PP) nonwoven fabrics with graphene oxide (GO) dispersions in N,N-dimethylformamide (DMF), followed by the chemical reduction of GO with hydroiodic acid (HI). GO as an amphiphilic macromolecule can be dispersed in DMF homogeneously at a concentration of 5 mg/mL, which has much lower surface tension (37.5 mN/m) than that of GO in water (72.9 mN/m, at 5 mg/mL). The hydrophobic PP nonwoven has a surface energy of 30.1 mN/m, close to the surface tension of GO in DMF. Therefore, the PP nonwoven can be easily wetted by the GO/DMF dispersion without any pretreatment. Soaking PP nonwoven in a GO/DMF dispersion leads to uniform coatings of GO on PP-fiber surfaces. After chemical reduction of GO to graphene, the resulting PP/graphene nonwoven composite offers an electrical conductivity of 35.6 S m -1 at graphene loading of 5.2 wt %, the highest among the existing conductive PP systems reported, indicating that surface tension of coating baths has significant impact on the coating uniformity and affinity. The conductivity of our PP/graphene nonwoven is also stable against stirring washing test. In addition, here we demonstrate a monolithic supercapacitor derived from the PP-GO nonwoven composite by using a direct laser-patterning process. The resulted sandwich supercapacitor shows a high areal capacitance of 4.18 mF/cm 2 in PVA-H 2 SO 4 gel electrolyte. The resulting highly conductive or capacitive PP/graphene nonwoven carries great promise to be used as electronic textiles.

  18. High strain rate superplasticity in metals and composites

    Energy Technology Data Exchange (ETDEWEB)

    Nieh, T.G.; Wadsworth, J. [Lawrence Livermore National Lab., CA (United States); Higashi, K. [Osaka Prefecture Univ., Sakai (Japan). Dept. of Mechanicl Systems Engineering

    1993-07-01

    Superplastic behavior at very high strain rates (at or above 1 s{sup {minus}1}) in metallic-based materials is an area of increasing interest. The phenomenon has been observed quite extensively in metal alloys, metal-matrix composites (MMC), and mechanically-alloyed (MA) materials. In the present paper, experimental results on high strain rate behavior in 2124 Al-based materials, including Zr-modified 2124, SiC-reinforced 2124, MA 2124, and MA 2124 MMC, are presented. Except for the required fine grain size, details of the structural requirements of this phenomenon are not yet understood. Despite this, a systematic approach to produce high strain rate superplasticity (HSRS) in metallic materials is given in this paper. Evidences indicate that the presence of a liquid phase, or a low melting point region, at boundary interfaces is responsible for HSRS.

  19. PHYSICAL CHARACTERIZATION OF ∼2 m DIAMETER NEAR-EARTH ASTEROID 2015 TC25: A POSSIBLE BOULDER FROM E-TYPE ASTEROID (44) NYSA

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Vishnu; Sanchez, Juan A.; Bottke, William F.; Thirouin, Audrey; Rivera-Valentin, Edgard G.; Kelley, Michael S.; Ryan, William; Cloutis, Edward A.; Tegler, Stephen C.; Ryan, Eileen V.; Taylor, Patrick A.; Richardson, James E.; Le Corre, Lucille [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States); Moskovitz, Nicholas [Lowell Observatory, Flagstaff, AZ 86001 (United States)

    2016-12-01

    Small near-Earth asteroids (NEAs) (<20 m) are interesting, because they are progenitors for meteorites in our terrestrial collection. The physical characteristics of these small NEAs are crucial to our understanding of the effectiveness of our atmosphere in filtering low-strength impactors. In the past, the characterization of small NEAs has been a challenge, because of the difficulty in detecting them prior to close Earth flyby. In this study, we physically characterized the 2 m diameter NEA 2015 TC25 using ground-based optical, near-infrared and radar assets during a close flyby of the Earth (distance 128,000 km) in 2015 October 12. Our observations suggest that its surface composition is similar to aubrites, a rare class of high-albedo differentiated meteorites. Aubrites make up only 0.14% of all known meteorites in our terrestrial meteorite collection. 2015 TC25 is also a very fast rotator with a period of 133 ± 6 s. We combined the spectral and dynamical properties of 2015 TC25 and found the best candidate source body in the inner main belt to be the 70 km diameter E-type asteroid (44) Nysa. We attribute the difference in spectral slope between the two objects to the lack of regolith on the surface of 2015 TC25. Using the albedo of E-type asteroids (50%–60%) we refine the diameter of 2015 TC25 to 2 m, making it one of the smallest NEAs ever to be characterized.

  20. High Performance Brittle Matrices and Brittle Matrix Composites. Book 1

    Science.gov (United States)

    1989-12-31

    Metall., 20 (1986), 285-289. 14. P.D. Funkenbusch, T.H. Courtney and D.G. Kubisch , "Fabricability and Microstructural Development in Cold Worked Metal...Matrix Composites", Scripta Metall., 18(1984), 1099-1104. 15. D.G. Kubisch and T.H. Courtney, "The Processing and Properties of Heavi- ly Cold Worked...oxidation resistance is also required, and must be an integral part of th’ alloy development program. High temperature oxidation resistance can be achieved

  1. Simulation of Fatigue Behavior of High Temperature Metal Matrix Composites

    Science.gov (United States)

    Tong, Mike T.; Singhal, Suren N.; Chamis, Christos C.; Murthy, Pappu L. N.

    1996-01-01

    A generalized relatively new approach is described for the computational simulation of fatigue behavior of high temperature metal matrix composites (HT-MMCs). This theory is embedded in a specialty-purpose computer code. The effectiveness of the computer code to predict the fatigue behavior of HT-MMCs is demonstrated by applying it to a silicon-fiber/titanium-matrix HT-MMC. Comparative results are shown for mechanical fatigue, thermal fatigue, thermomechanical (in-phase and out-of-phase) fatigue, as well as the effects of oxidizing environments on fatigue life. These results show that the new approach reproduces available experimental data remarkably well.

  2. Antifungal Tc17 cells are durable and stable, persisting as long-lasting vaccine memory without plasticity towards IFNγ cells.

    Directory of Open Access Journals (Sweden)

    Som Gowda Nanjappa

    2017-05-01

    Full Text Available Our understanding of persistence and plasticity of IL-17A+ memory T cells is clouded by conflicting results in models analyzing T helper 17 cells. We studied memory IL-17A+ CD8+ T-cell (Tc17 homeostasis, persistence and plasticity during fungal vaccine immunity. We report that vaccine-induced memory Tc17 cells persist with high fidelity to the type 17 phenotype. Tc17 cells persisted durably for a year as functional IL-17A+ memory cells without converting to IFNγ+ (Tc1 cells, although they produced multiple type I cytokines in the absence of residual vaccine antigen. Memory Tc17 cells were canonical CD8+ T cells with phenotypic features distinct from Tc1 cells, and were Ror(γthi, TCF-1hi, T-betlo and EOMESlo. In investigating the bases of Tc17 persistence, we observed that memory Tc17 cells had much higher levels of basal homeostatic proliferation than did Tc1 cells. Conversely, memory Tc17 cells displayed lower levels of anti-apoptotic molecules Bcl-2 and Bcl-xL than Tc1 cells, yet were resistant to apoptosis. Tc1 cells required Bcl-2 for their survival, but Bcl-2 was dispensable for the maintenance of Tc17 cells. Tc17 and Tc1 cells displayed different requirements for HIF-1α during effector differentiation and sustenance and memory persistence. Thus, antifungal vaccination induces durable and stable memory Tc17 cells with distinct requirements for long-term persistence that distinguish them from memory Tc1 cells.

  3. Acute thromboscintigraphy with (99m)Tc-apcitide: Results of the phase 3 multicenter clinical trial comparing (99m)Tc-apcitide scintigraphy with contrast venography for

    National Research Council Canada - National Science Library

    Raymond Taillefer; Stephen Edell; Grant Innes; John Lister-James

    2000-01-01

    (99m)Tc-apcitide (formerly known as (99m)Tc-P280) is a radiolabeled peptide that binds with high affinity and specificity to the glycoprotein IIb/IIIa receptors expressed on the activated platelets that are involved in acute thrombosis...

  4. Molybdenum target specifications for cyclotron production of 99mTc based on patient dose estimates.

    Science.gov (United States)

    Hou, X; Tanguay, J; Buckley, K; Schaffer, P; Bénard, F; Ruth, T J; Celler, A

    2016-01-21

    In response to the recognized fragility of reactor-produced (99)Mo supply, direct production of (99m)Tc via (100)Mo(p,2n)(99m)Tc reaction using medical cyclotrons has been investigated. However, due to the existence of other Molybdenum (Mo) isotopes in the target, in parallel with (99m)Tc, other technetium (Tc) radioactive isotopes (impurities) will be produced. They will be incorporated into the labeled radiopharmaceuticals and result in increased patient dose. The isotopic composition of the target and beam energy are main factors that determine production of impurities, thus also dose increases. Therefore, they both must be considered when selecting targets for clinical (99m)Tc production. Although for any given Mo target, the patient dose can be predicted based on complicated calculations of production yields for each Tc radioisotope, it would be very difficult to reverse these calculations to specify target composition based on dosimetry considerations. In this article, a relationship between patient dosimetry and Mo target composition is studied. A simple and easy algorithm for dose estimation, based solely on the knowledge of target composition and beam energy, is described. Using this algorithm, the patient dose increase due to every Mo isotope that could be present in the target is estimated. Most importantly, a technique to determine Mo target composition thresholds that would meet any given dosimetry requirement is proposed.

  5. Bimetallic Porous Iron (pFe) Materials for Remediation/Removal of Tc from Aqueous Systems

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-29

    Remediation of Tc remains an unresolved challenge at SRS and other DOE sites. The objective of this project was to develop novel bimetallic porous iron (pFe) materials for Tc removal from aqueous systems. We showed that the pFe is much more effective in removing TcO4 - (×30) and ReO4 - (×8) from artificial groundwater than granular iron. Tc K-edge XANES spectroscopy indicated that Tc speciation on the pFe was 18% adsorbed TcO4 -, 28% Tc(IV) in Tc dioxide and 54% Tc(IV) into the structure of Fe hydroxide. A variety of catalytic metal nanoparticles (i.e., Ni, Cu, Zn, Ag, Sn and Pd) were successfully deposited on the pFe using scalable chemical reduction methods. The Zn-pFe was outstanding among the six bimetallic pFe materials, with a capacity increase of >100% for TcO4 - removal and of 50% for ReO4 - removal, compared to the pFe. These results provide a highly applicable platform for solving critical DOE and industrial needs related to nuclear environmental stewardship and nuclear power production.

  6. Metabolic comparison of radiolabeled bleomycin and bleomycin-glucuronide labeled with 99mTc.

    Science.gov (United States)

    Koçan, Feray; Avcıbaşı, Ugur; Unak, Perihan; Müftüler, Fazilet Zümrüt Biber; Içhedef, Cigdem A; Demiroğlu, Hasan; Gümüşer, Fikriye G

    2011-10-01

    The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with (99m)Tc ((99m)Tc-BLM and (99m)Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with (99m)Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of (99m)Tc-BLM and (99m)Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for (99m)Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for (99m)Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the (99m)Tc-BLMG was found to be better than that of (99m)Tc-BLM.

  7. Electron Beam Cured Epoxy Resin Composites for High Temperature Applications

    Science.gov (United States)

    Janke, Christopher J.; Dorsey, George F.; Havens, Stephen J.; Lopata, Vincent J.; Meador, Michael A.

    1997-01-01

    Electron beam curing of Polymer Matrix Composites (PMC's) is a nonthermal, nonautoclave curing process that has been demonstrated to be a cost effective and advantageous alternative to conventional thermal curing. Advantages of electron beam curing include: reduced manufacturing costs; significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvement in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance the electron beam curing of PMC technology. Over the last several years a significant amount of effort within the CRADA has been devoted to the development and optimization of resin systems and PMCs that match the performance of thermal cured composites. This highly successful materials development effort has resulted in a board family of high performance, electron beam curable cationic epoxy resin systems possessing a wide range of excellent processing and property profiles. Hundreds of resin systems, both toughened and untoughened, offering unlimited formulation and processing flexibility have been developed and evaluated in the CRADA program.

  8. Matrix free fiber reinforced polymeric composites via high-temperature high-pressure sintering

    Science.gov (United States)

    Xu, Tao

    2004-11-01

    A novel manufacturing process called high-temperature high-pressure sintering was studied and explored. Solid fiber reinforced composites are produced by consolidating and compacting layers of polymeric fabrics near their melting temperature under high pressure. There is no need to use an additional matrix as a bonding material. Partial melting and recrystallization of the fibers effectively fuse the material together. The product is called a "matrix free" fiber reinforced composite and essentially a one-polymer composite in which the fiber and the matrix have the same chemical composition. Since the matrix is eliminated in the process, it is possible to achieve a high fiber volume fraction and light weight composite. Interfacial adhesion between fibers and matrix is very good due to the molecular continuity throughout the system and the material is thermally shapeable. Plain woven Spectra RTM cloth made of SpectraRTM fiber was used to comprehensively study the process. The intrinsic properties of the material demonstrate that matrix free SpectraRTM fiber reinforced composites have the potential to make ballistic shields such as body armor and helmets. The properties and structure of the original fiber and the cloth were carefully examined. Optimization of the processing conditions started with the probing of sintering temperatures by Differential Scanning Calorimetry. Coupled with the information from structural, morphological and mechanical investigations on the samples sintered at different processing conditions, the optimal processing windows were determined to ensure that the outstanding original properties of the fibers translate into high ballistic performance of the composites. Matrix free SpectraRTM composites exhibit excellent ballistic resistance in the V50 tests conducted by the US Army. In the research, process-structure-property relationship is established and correlations between various properties and structures are understood. Thorough knowledge is

  9. Risk assessment of desert pollution on composite high voltage insulators.

    Science.gov (United States)

    El-Shahat, Mohammed; Anis, Hussein

    2014-09-01

    Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber) insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator's leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing - and thus justifying - the use of this type of insulators in Sinai and similar critical areas.

  10. Risk assessment of desert pollution on composite high voltage insulators

    Directory of Open Access Journals (Sweden)

    Mohammed El-Shahat

    2014-09-01

    Full Text Available Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator’s leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing – and thus justifying – the use of this type of insulators in Sinai and similar critical areas.

  11. Properties of Polymer Composites Used in High-Voltage Applications

    Directory of Open Access Journals (Sweden)

    Ilona Pleşa

    2016-04-01

    Full Text Available The present review article represents a comprehensive study on polymer micro/nanocomposites that are used in high-voltage applications. Particular focus is on the structure-property relationship of composite materials used in power engineering, by exploiting fundamental theory as well as numerical/analytical models and the influence of material design on electrical, mechanical and thermal properties. In addition to describing the scientific development of micro/nanocomposites electrical features desired in power engineering, the study is mainly focused on the electrical properties of insulating materials, particularly cross-linked polyethylene (XLPE and epoxy resins, unfilled and filled with different types of filler. Polymer micro/nanocomposites based on XLPE and epoxy resins are usually used as insulating systems for high-voltage applications, such as: cables, generators, motors, cast resin dry-type transformers, etc. Furthermore, this paper includes ample discussions regarding the advantages and disadvantages resulting in the electrical, mechanical and thermal properties by the addition of micro- and nanofillers into the base polymer. The study goals are to determine the impact of filler size, type and distribution of the particles into the polymer matrix on the electrical, mechanical and thermal properties of the polymer micro/nanocomposites compared to the neat polymer and traditionally materials used as insulation systems in high-voltage engineering. Properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, erosion resistance, space charge behavior, electric breakdown, tracking and electrical tree resistance, thermal conductivity, tensile strength and modulus, elongation at break of micro- and nanocomposites based on epoxy resin and XLPE are analyzed. Finally, it was concluded that the use of polymer micro/nanocomposites in electrical engineering is very promising and further research work

  12. Testing of fiber composites at high strain rates

    Science.gov (United States)

    Daniel, I. M.; Liber, T.

    1978-01-01

    An experimental investigation was conducted to determine strain rate effects in fiber composites. Unidirectional composite specimens of boron/epoxy, graphite/epoxy, S-glass/epoxy and Kevlar/epoxy were tested at tensile strain rates of up to 27 m/m/sec. Longitudinal, transverse and in-plane shear properties, including modulus, Poisson's ratio, strength and ultimate strain, were determined by testing 0-, 90and 10-degree unidirectional coupons. Strains were measured by means of strain gages bonded on the coupons and loads were measured by means of a strain gage load cell. All specimens were loaded in an electrohydraulic loading system. The 0-degree properties which are governed by the fibers do not vary much with strain rate except for the Kevlar/epoxy material which shows an increase in both modulus and strength. The strain rate effects on 90-degree properties were small with a general trend toward higher strength with increasing strain rate. The most noticeable effect was on in-plane shear properties with shear strength values at high strain rates approximately fifteen percent higher than static values.

  13. High breakdown-strength composites from liquid silicone rubbers

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Zakaria, Shamsul Bin; Yu, Liyun

    2014-01-01

    In this paper we investigate the performance of liquid silicone rubbers (LSRs) as dielectric elastomer transducers. Commonly used silicones in this application include room-temperature vulcanisable (RTV) silicone elastomers and composites thereof. Pure LSRs and their composites with commercially...

  14. Estimation of myocardial perfusion and viability using simultaneous 99mTc-tetrofosmin--FDG collimated SPECT.

    Science.gov (United States)

    Fukuchi, K; Katafuchi, T; Fukushima, K; Shimotsu, Y; Toba, M; Hayashida, K; Takamiya, M; Ishida, Y

    2000-08-01

    This study was designed to elucidate the usefulness of crosstalk correction for dual-isotope simultaneous acquisition (DISA) with 99mTc-tetrofosmin and FDG in estimating myocardial perfusion and viability. Eighteen patients with coronary artery disease were studied. First, SPECT was performed with a low-energy high-resolution collimator after a single injection of 99mTc-tetrofosmin (single 99mTc-tetrofosmin). Second, PET and DISA with an ultra-high-energy collimator were performed after glucose loading and an injection of FDG. DISA was designed to operate with simultaneous 3-channel acquisition, and weighted scatter correction of crosstalk from the 18F photopeak to the 99mTc photopeak was performed by modification of an existing dual-window technique. The FDG SPECT images were compared with the images obtained by PET. Both crosstalk-corrected and uncorrected 99mTc-tetrofosmin images were generated and compared with the single 99mTc-tetrofosmin images. Regional percentage uptake of FDG agreed well between DISA and PET. However, regional percentage uptake of 99mTc-tetrofosmin was generally higher on the uncorrected 99mTc-tetrofosmin images than on the single 99mTc-tetrofosmin images, especially in areas of low flow (percentage count of 99mTc-tetrofosmin > or = 50%). The crosstalk correction contributed to improving the agreement between regional percentage uptakes and significantly improved the detectability of myocardial perfusion-metabolism mismatching. With 3-channel acquisition and weighted-scatter correction of crosstalk from the 18F photopeak to the 99mTc photopeak, DISA with 99mTc-tetrofosmin and FDG is feasible for assessing regional myocardial perfusion and viability.

  15. Host cell invasion and oral infection by Trypanosoma cruzi strains of genetic groups TcI and TcIV from chagasic patients.

    Science.gov (United States)

    Maeda, Fernando Yukio; Clemente, Tatiana Mordente; Macedo, Silene; Cortez, Cristian; Yoshida, Nobuko

    2016-04-01

    Outbreaks of acute Chagas disease by oral infection have been reported frequently over the last ten years, with higher incidence in northern South America, where Trypanosoma cruzi lineage TcI predominates, being responsible for the major cause of resurgent human disease, and a small percentage is identified as TcIV. Mechanisms of oral infection and host-cell invasion by these parasites are poorly understood. To address that question, we analyzed T. cruzi strains isolated from chagasic patients in Venezuela, Guatemala and Brazil. Trypanosoma cruzi metacyclic trypomastigotes were orally inoculated into mice. The mouse stomach collected four days later, as well as the stomach and the heart collected 30 days post-infection, were processed for histological analysis. Assays to mimic parasite migration through the gastric mucus layer were performed by counting the parasites that traversed gastric mucin-coated transwell filters. For cell invasion assays, human epithelial HeLa cells were incubated with metacyclic forms and the number of internalized parasites was counted. All TcI and TcIV T. cruzi strains were poorly infective by the oral route. Parasites were either undetectable or were detected in small numbers in the mouse stomach four days post oral administration. Replicating parasites were found in the stomach and/or in the heart 30 days post-infection. As compared to TcI lineage, the migration capacity of TcIV parasites through the gastric mucin-coated filter was higher but lower than that exhibited by TcVI metacyclic forms previously shown to be highly infective by the oral route. Expression of pepsin-resistant gp90, the surface molecule that downregulates cell invasion, was higher in TcI than in TcIV parasites and, accordingly, the invasion capacity of TcIV metacyclic forms was higher. Gp90 molecules spontaneously released by TcI metacyclic forms inhibited the parasite entry into host cells. TcI parasites exhibited low intracellular replication rate. Our findings

  16. Microstructural Design & Optimization of Highly Filled Epoxy Based Composites

    Science.gov (United States)

    2009-11-01

    properties of the constituents can affect the properties of particulate composites. In composites of Al2O3 particles in epoxy ( Epon 828 /Z), increasing the...composites. In composites of Al2O3 particles in epoxy ( Epon 828 /Z), increasing the particle concentration and decreasing the particle size is found...2004. 20: p. 481-495. 13. Jordan, J.L., C.R. Siviour, and J.R. Foley, Mechanical properties of Epon 826/DEA epoxy. Mechanics of Time Dependant

  17. High resolution miniaturized stepper ultrasonic motor using differential composite motion.

    Science.gov (United States)

    Chu, Xiangcheng; Xing, Zengping; Li, Longtu; Gui, Zhilun

    2004-03-01

    Experiments show that there is a limited minimum stepped angle in ultrasonic motors (USM). The research on the minimum angle of stepper USM with 15 mm in diameter and wobbling mode is being carried out. This paper presents a novel way to decrease the minimum stepped angle of USM based on the principle of differential composite motion (DCM), i.e. clockwise and counterclockwise rotation. The prototype was fabricated and experiments proved that this method is useful and also keeps a high torque for a large stepped angle. The stator of the prototype is steel, and rotor is fiberglass, antifriction material or steel. The prototype can operate well over 150 h with a 5 kHz wide frequency band. The minimum stepped angle is 46" using a coventional method while 12" using DCM method proposed in this paper.

  18. Preparation and characterization of [99TcO] apcitide: a technetium labeled peptide.

    Science.gov (United States)

    Francesconi, Lynn C; Zheng, Yongyong; Bartis, Judit; Blumenstein, Michael; Costello, Catherine; De Rosch, Mark A

    2004-05-03

    [99mTcO] apcitide (99mTcO(P246)), the technetium complex of the 13 amino acid, apcitide, cyclo-(D-Tyr-Apc-Gly-Asp-Cys)-Gly-Gly-Cys(Acm)-Gly-Cys(Acm)-Gly-Gly-Cys-NH2, where Apc is L-[S-(3-aminopropyl)]cysteine (an arginine mimetic) and Acm is the acetamidomethyl protecting group, has high affinity and selectivity for the GPIIb/IIIa receptor that is expressed on the membrane surface of activated platelets and plays an integral role in platelet aggregation and thrombus formation. Bibapcitide, a 26 amino acid, bis-succinimidomethyl ether-linked dimer of the peptide apcitide has been formulated as a single-vial, lyophilized kit having the trade name AcuTect. When sterile, nonpyrogenic sodium pertechnetate (99mTcO4-) in 0.9% sodium chloride is added to the AcuTect radiopharmaceutical kit and the resulting kit is heated, [99mTcO] apcitide forms. This is the first radiopharmaceutical to target acute deep vein thrombosis (DVT) in the lower extremities. We report here the preparation, purification, and isolation of the 99Tc complex of apcitide and its characterization to determine the mode of binding of Tc to apcitide. [99TcO] apcitide was prepared, on the macroscopic level, by reaction of [99TcOCl4]- with apcitide, purified by preparative HPLC and isolated as a trifluoroacetate salt. [99TcO] apcitide can also be formed from the reaction of bibapcitide and 99TcO4- in the presence of Sn(II) and glucoheptonate at 80 degrees C, conditions that mimic the radiopharmaceutical kit preparation. FTIR data show a Tc=O stretch at 961.2 cm(-1), in the range observed for anionic [TcVO]3+ amide thiolate complexes. The mass spectral data is in agreement with the formula, [C51H73O20N17S5Tc]-, consistent with retention of Acm groups and the Tc binding in the Gly11-Gly12-Cys13 region of the peptide. Despite significant spectral overlap due to numerous similar amino acids, all protons of apcitide and [99TcO] apcitide were unambiguously assigned. The observation of two nonequivalent Acm groups

  19. High T$_{c}$ superconductors and related transition metal oxides special contributions in honor of K. Alex Müller on the occasion of his 80th birthday

    CERN Document Server

    Bussmann-Holder, Annette

    2007-01-01

    This book containing 30 articles written by highly reputed experts is dedicated to K. Alex Müller on the occasion of his 80th birthday. The contributions reflect the major research areas of K. Alex Müller which he activated in high temperature superconductivity and phase transitions. They are theoretical as well as experimental ones and focus mainly on high temperature superconductivity. A smaller part deals with ferroelectricity and their applications. Also in this field there have recently been major break throughs experimentally as well as theoretically which will be addressed by the invited authors. During the scientific career of K. Alex Müller he made major advances in the understanding of ferroelectricity, which used to be his major research field. The discovery of superconductivity in cuprates for which he received together with J. Georg Bednorz the Nobel Prize in 1987 has not diminished his interest in this area, but has enlarged his activities considerably.

  20. Electronic materials high-T(sub c) superconductivity polymers and composites structural materials surface science and catalysts industry participation

    Science.gov (United States)

    1988-01-01

    The fifth year of the Center for Advanced Materials was marked primarily by the significant scientific accomplishments of the research programs. The Electronics Materials program continued its work on the growth and characterization of gallium arsenide crystals, and the development of theories to understand the nature and distribution of defects in the crystals. The High Tc Superconductivity Program continued to make significant contributions to the field in theoretical and experimental work on both bulk materials and thin films and devices. The Ceramic Processing group developed a new technique for cladding YBCO superconductors for high current applications in work with the Electric Power Research Institute. The Polymers and Composites program published a number of important studies involving atomistic simulations of polymer surfaces with excellent correlations to experimental results. The new Enzymatic Synthesis of Materials project produced its first fluorinated polymers and successfully began engineering enzymes designed for materials synthesis. The structural Materials Program continued work on novel alloys, development of processing methods for advanced ceramics, and characterization of mechanical properties of these materials, including the newly documented characterization of cyclic fatigue crack propagation behavior in toughened ceramics. Finally, the Surface Science and Catalysis program made significant contributions to the understanding of microporous catalysts and the nature of surface structures and interface compounds.

  1. Polymer nanocomposites for high-temperature composite repair

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Xia [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    A novel repair agent for resin-injection repair of advanced high temperature composites was developed and characterized. The repair agent was based on bisphenol E cyanate ester (BECy) and reinforced with alumina nanoparticles. To ensure good dispersion and compatibility with the BECy matrix in nanocomposites, the alumina nanoparticles were functionalized with silanes. The BECy nanocomposites, containing bare and functionalized alumina nanoparticles, were prepared and evaluated for their thermal, mechanical, rheological, and viscoelastic properties. The monomer of BECy has an extremely low viscosity at ambient temperature, which is good for processability. The cured BECy polymer is a highly cross-linked network with excellent thermal mechanical properties, with a high glass transition temperature (Tg) of 270 C and decomposition temperature above 350 C. The incorporation of alumina nanoparticles enhances the mechanical and rheological properties of the BECy nanocomposites. Additionally, the alumina nanoparticles are shown to catalyze the cure of BECy. Characterization of the nanocomposites included dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy. The experimental results show that the BECy nanocomposite is a good candidate as repair agent for resin-injection repair applications.

  2. Polyimide/Glass Composite High-Temperature Insulation

    Science.gov (United States)

    Pater, Ruth H.; Vasquez, Peter; Chatlin, Richard L.; Smith, Donald L.; Skalski, Thomas J.; Johnson, Gary S.; Chu, Sang-Hyon

    2009-01-01

    Lightweight composites of RP46 polyimide and glass fibers have been found to be useful as extraordinarily fire-resistant electrical-insulation materials. RP46 is a polyimide of the polymerization of monomeric reactants (PMR) type, developed by NASA Langley Research Center. RP46 has properties that make it attractive for use in electrical insulation at high temperatures. These properties include high-temperature resistance, low relative permittivity, low dissipation factor, outstanding mechanical properties, and excellent resistance to moisture and chemicals. Moreover, RP46 contains no halogen or other toxic materials and when burned it does not produce toxic fume or gaseous materials. The U. S. Navy has been seeking lightweight, high-temperature-resistant electrical-insulation materials in a program directed toward reducing fire hazards and weights in ship electrical systems. To satisfy the requirements of this program, an electrical-insulation material must withstand a 3-hour gas-flame test at 1,600 F (about 871 C). Prior to the development reported here, RP46 was rated for use at temperatures from -150 to +700 F (about -101 to 371 C), and no polymeric product - not even RP46 - was expected to withstand the Navy 3-hour gas-flame test.

  3. High Temperature Permeability of Carbon Cloth Phenolic Composite

    Science.gov (United States)

    Park, O. Y.; Lawrence, T. W.

    2003-01-01

    The carbon fiber phenolic resin composite material used for the RSRM nozzle insulator occasionally experiences problems during operation from pocketing or spalling-like erosion and lifting of plies into the char layer. This phenomenon can be better understood if the permeability of the material at elevated temperatures is well defined. This paper describes an experimental approach to determining high temperature permeability of the carbon phenolic material used as the RSRM nozzle liner material. Two different approaches were conducted independently using disk and bar type specimens with the designed permeability apparatus. The principle of the apparatus was to subject a test specimen to a high pressure differential and a heat supply and to monitor both the pressure and temperature variations resulting from gas penetration through the permeable wall between the two chambers. The bar types, especially designed to eliminate sealing difficulties at a high temperature environment, were directly exposed to real time temperature elevation from 22 C to 260 C during the test period. The disk types were pre-heat treated up to 300 C for 8 hours and cooled to room temperature before testing. Nonlinear variation of downstream pressure at a certain temperature range implied moisture release and matrix pyrolysis. Permeability was calculated using a semi-numerical model of quasi-steady state. The test results and the numerical model are discussed in the paper.

  4. The compositional variation of synthetic sodic amphiboles at high and ultra-high pressures

    Science.gov (United States)

    Tropper, P.; Manning, C. E.; Essene, E. J.; Kao, L.-S.

    Sodic amphiboles in high pressure and ultra-high pressure (UHP) metamorphic rocks are complex solid solutions in the system Na2O-MgO-Al2O3-SiO2-H2O (NMASH) whose compositions vary with pressure and temperature. We conducted piston-cylinder experiments at 20-30kbar and 700-800°C to investigate the stability and compositional variations of sodic amphiboles, based on the reaction glaucophane=2jadeite+talc, by using the starting assemblage of natural glaucophane, talc and quartz, with synthetic jadeite. A close approach to equilibrium was achieved by performing compositional reversals, by evaluating compositional changes with time, and by suppressing the formation of Na-phyllosilicates. STEM observations show that the abundance of wide-chain structures in the synthetic amphiboles is low. An important feature of sodic amphibole in the NMASH system is that the assemblage jadeite-talc+/-quartz does not fix its composition at glaucophane. This is because other amphibole species such as cummingtonite (Cm), nyböite (Nyb), Al-Na-cummingtonite (Al-Na-Cm) and sodium anthophyllite (Na-Anth) are also buffered via the model reactions: 3cummingtonite+4quartz+4H2O=7talc, nyböite+3quartz=3jadeite+talc, 3Al-Na-cummingtonite + 11quartz + 2H2O=6jadeite + 5talc, and 3 sodium anthophyllite+13quartz+4H2O=3 jadeite + 7talc. We observed that at all pressures and temperatures investigated, the compositions of newly grown amphiboles deviate significantly from stoichiometric glaucophane due to varying substitutions of AlIV for Si, Mg on the M(4) site, and Na on the A-site. The deviation can be described chiefly by two compositional vectors: [NaAAlIV][□ASi] (edenite) toward nyböite, and [Na(M4)AlVI][Mg(M4)MgVI] toward cummingtonite. The extent of nyböite and cummingtonite substitution increases with temperature and decreases with pressure in the experiments. Similar compositional variations occur in sodic amphiboles from UHP rocks. The experimentally calibrated compositional changes

  5. Energy Gaps in the Failed High-Tc Superconductor La_1.875Ba_0.125Cu_O4

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, K.

    2011-08-19

    A central issue on high-T{sub c} superconductivity is the nature of the normal-state gap (pseudogap) in the underdoped regime and its relationship with superconductivity. Despite persistent efforts, theoretical ideas for the pseudogap evolve around fluctuating superconductivity, competing order and spectral weight suppression due to many-body effects. Recently, while some experiments in the superconducting state indicate a distinction between the superconducting gap and pseudogap, others in the normal state, either by extrapolation from high-temperature data or directly from La{sub 1.875}Ba{sub 0.125}CuO{sub 4} (LBCO-1/8) at low temperature, suggest the ground-state pseudogap is a single gap of d-wave form. Here we report angle-resolved photoemission (ARPES) data from LBCO-1/8, collected with improved experimental conditions, that reveal the ground-state pseudogap has a pronounced deviation from the simple d-wave form. It contains two distinct components: a d-wave component within an extended region around the node and the other abruptly enhanced close to the antinode, pointing to a dual nature of the pseudogap in this failed high-T{sub c} superconductor which involves a possible precursor pairing energy scale around the node and another of different but unknown origin near the antinode.

  6. Motion stability of the magnetic levitation and suspension with YBa2Cu3O7-x high-Tc superconducting bulks and NdFeB magnets

    Science.gov (United States)

    Li, Jipeng; Zheng, Jun; Huang, Huan; Li, Yanxing; Li, Haitao; Deng, Zigang

    2017-10-01

    The flux pinning effect of YBa2Cu3O7-x high temperature superconducting (HTS) bulk can achieve self-stable levitation over a permanent magnet or magnet array. Devices based on this phenomenon have been widely developed. However, the self-stable flux pinning effect is not unconditional, under disturbances, for example. To disclose the roots of this amazing self-stable levitation phenomenon in theory, mathematical and mechanical calculations using Lyapunov's stability theorem and the Hurwitz criterion were performed under the conditions of magnetic levitation and suspension of HTS bulk near permanent magnets in Halbach array. It is found that the whole dynamical system, in the case of levitation, has only one equilibrium solution, and the singular point is a stable focus. In the general case of suspension, the system has two singular points: one is a stable focus, and the other is an unstable saddle. With the variation of suspension force, the two first-order singular points mentioned earlier will get closer and closer, and finally degenerate to a high-order singular point, which means the stable region gets smaller and smaller, and finally vanishes. According to the center manifold theorem, the high-order singular point is unstable. With the interaction force varying, the HTS suspension dynamical system undergoes a saddle-node bifurcation. Moreover, a deficient damping can also decrease the stable region. These findings, together with existing experiments, could enlighten the improvement of HTS devices with strong anti-interference ability.

  7. Evaluation of 99mTc-Labeled Cyclic RGD Dimers: Impact of Cyclic RGD Peptides and 99mTc Chelates on Biological Properties

    Science.gov (United States)

    Zhou, Yang; Kim, Young-Seung; Lu, Xin; Liu, Shuang

    2012-01-01

    The main objective of this study is to explore the impact of cyclic RGD peptides and 99mTc chelates on biological properties of 99mTc radiotracers. Cyclic RGD peptide conjugates, HYNIC-K(NIC)-RGD2 (HYNIC = 6-hydrazinonicotinyl; RGD2 = E[c(RGDfK)]2 and NIC = nicotinyl) HYNIC-K(NIC)-3G-RGD2 (3G-RGD2 = Gly-Gly-Gly-E[Gly-Gly-Gly-c(RGDfK)]2), and HYNIC-K(NIC)-3P-RGD2 (3P-RGD2 = PEG4-E[PEG4-c(RGDfK)]2), were prepared. Macrocyclic 99mTc complexes [99mTc(HYNIC-K(NIC)-RGD2)(tricine)] (1), [99mTc(HYNIC-K(NIC)-3G-RGD2)(tricine)] (2) and [99mTc(HYNIC-K(NIC)-3P-RGD2)(tricine)] (3) were evaluated for their biodistribution and tumor-targeting capability in athymic nude mice bearing MDA-MB-435 human breast tumor xenografts. It was found that 1, 2 and 3 could be prepared with high specific activity (~111GBq/3mol). All three 99mTc radiotracers have two major isomers, which show almost identical uptake in tumors and normal organs. Replacing the bulky and highly charged [99mTc(HYNIC)(tricine)(TPPTS)] (TPPTS = trisodium triphenylphosphine-3,3′,3″-trisulfonate) with a smaller [99mTc(HYNIC-K(NIC))(tricine)] resulted in less uptake in the kidneys and lungs for 3. Surprisingly, all three 99mTc radiotracers shared a similar tumor uptake (1: 5.73 ± 0.40 %ID/g; 2: 5.24 ± 1.09 %ID/g; and 3: 4.94 ± 1.71 %ID/g) at 60 min p.i. The metabolic stability of 99mTc radiotracers depends on cyclic RGD peptides (3P-RGD2 > 3G-RGD2 ~ RGD2) and 99mTc chelates ([99mTc(HYNIC)(tricine)(TPPTS)] > [99mTc(HYNIC-K(NIC))(tricine)]). Immunohistochemical studies revealed a linear relationship between the αvβ3 expression levels and tumor uptake or tumor/muscle ratios of 3, suggesting that 3 is useful for monitoring the tumor αvβ3 expression. Complex 3 is a very attractive radiotracer for detection of integrin αvβ3 –positive tumors. PMID:22369387

  8. Evaluation of 99mTc-labeled cyclic RGD dimers: impact of cyclic RGD peptides and 99mTc chelates on biological properties.

    Science.gov (United States)

    Zhou, Yang; Kim, Young-Seung; Lu, Xin; Liu, Shuang

    2012-03-21

    The main objective of this study is to explore the impact of cyclic RGD peptides and (99m)Tc chelates on biological properties of (99m)Tc radiotracers. Cyclic RGD peptide conjugates, HYNIC-K(NIC)-RGD(2) (HYNIC = 6-hydrazinonicotinyl; RGD(2) = E[c(RGDfK)](2) and NIC = nicotinyl), HYNIC-K(NIC)-3G-RGD(2) (3G-RGD(2) = Gly-Gly-Gly-E[Gly-Gly-Gly-c(RGDfK)](2)), and HYNIC-K(NIC)-3P-RGD(2) (3P-RGD(2) = PEG(4)-E[PEG(4)-c(RGDfK)](2)), were prepared. Macrocyclic (99m)Tc complexes [(99m)Tc(HYNIC-K(NIC)-RGD(2))(tricine)] (1), [(99m)Tc(HYNIC-K(NIC)-3G-RGD(2))(tricine)] (2), and [(99m)Tc(HYNIC-K(NIC)-3P-RGD(2))(tricine)] (3) were evaluated for their biodistribution and tumor-targeting capability in athymic nude mice bearing MDA-MB-435 human breast tumor xenografts. It was found that 1, 2, and 3 could be prepared with high specific activity (∼111 GBq/μmol). All three (99m)Tc radiotracers have two major isomers, which show almost identical uptake in tumors and normal organs. Replacing the bulky and highly charged [(99m)Tc(HYNIC)(tricine)(TPPTS)] (TPPTS = trisodium triphenylphosphine-3,3',3″-trisulfonate) with a smaller [(99m)Tc(HYNIC-K(NIC))(tricine)] resulted in less uptake in the kidneys and lungs for 3. Surprisingly, all three (99m)Tc radiotracers shared a similar tumor uptake (1, 5.73 ± 0.40%ID/g; 2, 5.24 ± 1.09%ID/g; and 3, 4.94 ± 1.71%ID/g) at 60 min p.i. The metabolic stability of (99m)Tc radiotracers depends on cyclic RGD peptides (3P-RGD(2) > 3G-RGD(2) ∼ RGD(2)) and (99m)Tc chelates ([(99m)Tc(HYNIC)(tricine)(TPPTS)] > [(99m)Tc(HYNIC-K(NIC))(tricine)]). Immunohistochemical studies revealed a linear relationship between the α(v)β(3) expression levels and tumor uptake or tumor/muscle ratios of 3, suggesting that 3 is useful for monitoring the tumor α(v)β(3) expression. Complex 3 is a very attractive radiotracer for detection of integrin α(v)β(3)-positive tumors.

  9. High performance dental resin composites with hydrolytically stable monomers.

    Science.gov (United States)

    Wang, Xiaohong; Huyang, George; Palagummi, Sri Vikram; Liu, Xiaohui; Skrtic, Drago; Beauchamp, Carlos; Bowen, Rafael; Sun, Jirun

    2018-02-01

    The objectives of this project were to: 1) develop strong and durable dental resin composites by employing new monomers that are hydrolytically stable, and 2) demonstrate that resin composites based on these monomers perform superiorly to the traditional bisphenol A glycidyl dimethacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) composites under testing conditions relevant to clinical applications. New resins comprising hydrolytically stable, ether-based monomer, i.e., triethylene glycol divinylbenzyl ether (TEG-DVBE), and urethane dimethacrylate (UDMA) were produced via composition-controlled photo-polymerization. Their composites contained 67.5wt% of micro and 7.5wt% of nano-sized filler. The performances of both copolymers and composites were evaluated by a battery of clinically-relevant assessments: degree of vinyl conversion (DC: FTIR and NIR spectroscopy); refractive index (n: optical microscopy); elastic modulus (E), flexural strength (F) and fracture toughness (K IC ) (universal mechanical testing); Knoop hardness (HK; indentation); water sorption (W sp ) and solubility (W su ) (gravimetry); polymerization shrinkage (S v ; mercury dilatometry) and polymerization stress (tensometer). The experimental UDMA/TEG-DVBE composites were compared with the Bis-GMA/TEGDMA composites containing the identical filler contents, and with the commercial micro hybrid flowable composite. UDMA/TEG-DBVE composites exhibited n, E, W sp , W su and S v equivalent to the controls. They outperformed the controls with respect to F (up to 26.8% increase), K IC (up to 27.7% increase), modulus recovery upon water sorption (full recovery vs. 91.9% recovery), and stress formation (up to 52.7% reduction). In addition, new composites showed up to 27.7% increase in attainable DC compared to the traditional composites. Bis-GMA/TEGDMA controls exceeded the experimental composites with respect to only one property, the composite hardness. Significantly, up to 18.1% lower HK values in

  10. Radiochemical purity of Mo and Tc solution obtained after irradiation and dissolution of Mo-100-enriched and ultra-high-purity natural Mo disks

    Energy Technology Data Exchange (ETDEWEB)

    Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey D. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    Four irradiations of ultra-high-purity natural Mo targets and one irradiation using 97.4% Mo-100-enriched material were performed. The purpose of these irradiations was to determine whether the presence of Sn stabilizer in the H2O2 used for the dissolution of sintered Mo disks can affect the radiochemical purity of the final K2MoO4 in 5M KOH solution. Results from radiochemical purity tests performed using thin-layer paper chromatography show that even 2– 3× excess of Sn-stabilized H2O2 typically used for dissolution of sintered Mo disks did not affect the radiochemical purity of the final product.

  11. Transport measurements in superconductors: critical current of granular high TC ceramic superconductor samples; Medidas de transporte em supercondutores: corrente critica de supercondutores granulares de alta temperatura critica

    Energy Technology Data Exchange (ETDEWEB)

    Passos, W.A.C., E-mail: wagner.passos@univasf.edu.br [Universidade Federal do Vale do Sao Francisco (IPCM/UNIVASF), Juazeiro do Norte, BA (Brazil). Instituto de Pesquisas em Ciencia dos Materiais; Silva, E.B. [Companhia Energetica do Sao Francisco (CHESF), Recife, PE (Brazil)

    2016-07-01

    This work presents a method to obtain critical current of granular superconductors. We have carried out transport measurements (ρxT curves and VxI curves) in a YBa{sub 2}Cu{sub 3}O{sub 7-δ} sample to determine critical current density of it. Some specimens reveal a 'semiconductor-like' behavior (electrical resistivity decreases with increasing temperatures above critical temperature T{sub c} of material) competing with superconductor behavior. Due to high granular fraction of the sample, these competition is clearly noted in ρxT curves. Measurements carried out from 0 to 8500 Oe of applied field show the same behavior, and the critical current density of the samples is shown. (author)

  12. Ceramic Composite Mechanical Fastener System for High-Temperature Structural Assemblies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Under Phase I, the feasibility of a novel thermal stress-free ceramic composite mechanical fastener system suitable for assembly of high-temperature composite...

  13. Tc-99m HMPAO brain SPECT scanning in Munchausen syndrome.

    Science.gov (United States)

    Mountz, J M; Parker, P E; Liu, H G; Bentley, T W; Lill, D W; Deutsch, G

    1996-01-01

    Regional cerebral blood flow was studied in a patient with Munchausen syndrome using high resolution Tc-99m HMPAO SPECT. The scan demonstrated marked hyperperfusion of the right hemithalamus. The cranial CT scan was normal. The abnormal right hemithalamic blood flow is discussed in relation to the hypothesized neuropathy of this disorder. Images Figure 1 Figure 2 Figure 3 PMID:8580117

  14. High conducting oxide--sulfide composite lithium superionic conductor

    Science.gov (United States)

    Liang, Chengdu; Rangasamy, Ezhiylmurugan; Dudney, Nancy J.; Keum, Jong Kahk; Rondinone, Adam Justin

    2017-01-17

    A solid electrolyte for a lithium-sulfur battery includes particles of a lithium ion conducting oxide composition embedded within a lithium ion conducting sulfide composition. The lithium ion conducting oxide composition can be Li.sub.7La.sub.3Zr.sub.2O.sub.12 (LLZO). The lithium ion conducting sulfide composition can be .beta.-Li.sub.3PS.sub.4 (LPS). A lithium ion battery and a method of making a solid electrolyte for a lithium ion battery are also disclosed.

  15. AC-flux penetration into high-Tc superconductors with hall effects 2; Koon chodendotai ni okeru koryu jiba shinnyu to horu koka 2

    Energy Technology Data Exchange (ETDEWEB)

    Mawatari, Y. [Electrotechnical Laboratory, Tsukuba (Japan)

    1999-06-07

    It has been confirmed that high temperature superconductor can become the superclean condition in which mean free path is abnormally long in the scattering time of the quasiparticle in the nucleus of line of magnetic flux. Though in this condition, the Hall effect concerning magnetic flux motion remarkably appears, we have not studied it until now on pinning and AC characteristic which together considered Hall effect of line of magnetic flux. For this, we analyzed linear alternating current response of line of magnetic flux for minute alternating magnetic field on the basis of equation of motion of line of magnetic flux considering Hall effect theoretically, and line of magnetic flux had effective mass in the superclean condition, and it was reported that resonance phenomenas were generated in the last time. This time, we carried out magnetic flux motion, alternating magnetic field invasion and more and more detailed analysis on the alternating current permeability, and we examined new possibility of the phenomenon such as elliptic motion of line of magnetic flux and excitation of standing wave. (NEDO)

  16. Robust high temperature composite and CO sensor made from such composite

    Science.gov (United States)

    Dutta, Prabir K.; Ramasamy, Ramamoorthy; Li, Xiaogan; Akbar, Sheikh A.

    2010-04-13

    Described herein is a composite exhibiting a change in electrical resistance proportional to the concentration of a reducing gas present in a gas mixture, detector and sensor devices comprising the composite, a method for making the composite and for making devices comprising the composite, and a process for detecting and measuring a reducing gas in an atmosphere. In particular, the reducing gas may be carbon monoxide and the composite may comprise rutile-phase TiO2 particles and platinum nanoclusters. The composite, upon exposure to a gas mixture containing CO in concentrations of up to 10,000 ppm, exhibits an electrical resistance proportional to the concentration of the CO present. The composite is useful for making sensitive, low drift, fast recovering detectors and sensors, and for measuring CO concentrations in a gas mixture present at levels from sub-ppm up to 10,000 ppm. The composites, and devices made from the composites, are stable and operable in a temperature range of from about 450.degree. C. to about 700.degree. C., such as may be found in a combustion chamber.

  17. Potential value of color-coded dynamic breast-specific gamma-imaging; comparing {sup 99m}Tc-(V)-DMSA, {sup 99m}Tc-MIBI, and {sup 99m}Tc-HDP in a mouse mammary tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Leeuwen, Fijs W.B. van, E-mail: fw.v.leeuwen@nki.n [Departments of Radiology and Nuclear Medicine, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands); Buckle, Tessa; Batteau, Lukas; Pool, Bert; Sinaasappel, Michiel [Departments of Radiology and Nuclear Medicine, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands); Jonkers, Jos [Department of Molecular Biology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands); Gilhuijs, Kenneth G.A. [Departments of Radiology and Nuclear Medicine, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, 1066 CX Amsterdam (Netherlands)

    2010-12-15

    Using a mouse mammary tumor model based on orthotopic transplantation of luciferase-expressing mouse ILC cells (KEP1-Luc cells), we evaluated the diagnostic value of three clinically applied tracers: {sup 99m}Tc-(V)-DMSA, {sup 99m}Tc-MIBI, and {sup 99m}Tc-HDP. Uptake of the tracers is compared using static and dynamic imaging procedures. We found that dynamic imaging in combination with pixel-by-pixel color coding has an added value over (high resolution) static imaging procedures. Such dynamic imaging procedures could enhance the potential of breast-specific gamma-imaging.

  18. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

    2010-08-01

    Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

  19. Matter composition at high density by effective scaled lagrangian

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Chang Ho; Min, Dong Pil [Dept. of Physics, Seoul National Univ., Seoul (Korea, Republic of)

    1998-06-01

    We investigate the matter composition at around the neutron star densities with a model lagrangian satisfying Brown-Rho scaling law. We calculate the neutron star properties such as maximum mass, radius, hyperon compositions and central density. We compare our results with those of Walecka model. (orig.)

  20. Chitosan/kaolin composite porous microspheres with high hemostatic efficacy.

    Science.gov (United States)

    Sun, Xun; Tang, Zonghao; Pan, Meng; Wang, Zhengchao; Yang, Hongqin; Liu, Haiqing

    2017-12-01

    The hemostatic performance of chitosan was greatly improved by blending it with kaolin to fabricate porous composite microspheres (CSMS-K) through inverse emulsion method combining with thermally induced phase separation. The CSMS-K had high amount of interior and surface pores. The synergetic hemostatic competence of chitosan and kaolin components made the hemostatic efficacy of CSMS-K superior to chitosan porous microspheres (CSMS). The hemostatic time of CSMS-K3 in the rat tail amputation and liver laceration models was down to respective 120 and 99s from 183 and 134s of CSMS, and the blood loss of CSMS-K3 was respectively 65% and 36% of that of CSMS in the rat tail amputation and liver laceration models. The whole blood clotting kinetics proved that CSMS-K3 formed larger blood clots than CSMS and Celox within a same time period. Our results suggested that the CSMS-K is a potential quick pro-coagulant agent for traumatic hemorrhaging control. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Evaluation of the technical performance of novel holotranscobalamin (holoTC) assays in a multicenter European demonstration project.

    Science.gov (United States)

    Morkbak, Anne L; Heimdal, Randi M; Emmens, Kathleen; Molloy, Anne; Hvas, Anne-Mette; Schneede, Joern; Clarke, Robert; Scott, John M; Ueland, Per M; Nexo, Ebba

    2005-01-01

    A commercially available holotranscobalamin (holo-TC) radioimmunoassay (RIA) (Axis-Shield, Dundee, Scotland) was evaluated in four laboratories and compared with a holoTC ELISA run in one laboratory. The performance of the holoTC RIA assay was comparable in three of the four participating laboratories. The results from these three laboratories, involving at least 20 initial runs of "low", "medium" and "high" serum-based controls (mean holoTC concentrations 34, 60 and 110 pmol/L, respectively) yielded an intra-laboratory imprecision of 6-10%. No systematic inter-laboratory deviations were observed on runs involving 72 patient samples (holoTC concentration range 10-160 pmol/L). A fourth laboratory demonstrated higher assay imprecision for control samples and systematic deviation of results for the patient samples. Measurement of holoTC by ELISA showed an imprecision of 4-5%, and slightly higher mean values for the controls (mean holoTC concentrations 40, 70 and 114 pmol/L, respectively). Comparable results were obtained for the patient samples. The long-term intra-laboratory imprecision was 12% for the holoTC RIA and 6% for the ELISA. In conclusion, it would be prudent to check the calibration and precision prior to starting to use these holoTC assays in research or clinical practice. The results obtained using the holoTC RIA were similar to those obtained using the holoTC ELISA assay.

  2. High voltage cathode compositions for lithium-ion batteries

    Science.gov (United States)

    Lu, Zhonghua; Eberman, Kevin W

    2017-03-21

    A lithium transition metal oxide composition. The composition has the formula Li.sub.a[Li.sub.bNi.sub.cMn.sub.dCo.sub.e]O.sub.2, where a.gtoreq.0.9, b.gtoreq.0, c>0, d>0, e>0, b+c+d+e=1, 1.05.ltoreq.c/d.ltoreq.1.4, 0.05.ltoreq.e.ltoreq.0.30, 0.9.ltoreq.(a+b)/M.ltoreq.1.06, and M=c+d+e. The composition has an O3 type structure.

  3. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  4. Semiconductor/High-Tc-Superconductor Hybrid ICs

    Science.gov (United States)

    Burns, Michael J.

    1995-01-01

    Hybrid integrated circuits (ICs) containing both Si-based semiconducting and YBa(2)Cu(3)O(7-x) superconducting circuit elements on sapphire substrates developed. Help to prevent diffusion of Cu from superconductors into semiconductors. These hybrid ICs combine superconducting and semiconducting features unavailable in superconducting or semiconducting circuitry alone. For example, complementary metal oxide/semiconductor (CMOS) readout and memory devices integrated with fast-switching Josephson-junction super-conducting logic devices and zero-resistance interconnections.

  5. Recent achievements in Tc-99m radiopharmaceutical direct production by medical cyclotrons.

    Science.gov (United States)

    Boschi, Alessandra; Martini, Petra; Pasquali, Micol; Uccelli, Licia

    2017-09-01

    99mTc is the most commonly used radionuclide in the field of diagnostic imaging, a noninvasive method intended to diagnose a disease, assess the disease state and monitor the effects of treatments. Annually, the use of 99mTc, covers about 85% of nuclear medicine applications. This isotope releases gamma rays at about the same wavelength as conventional X-ray diagnostic equipment, and owing to its short half-life (t½ = 6 h) is ideal for diagnostic nuclear imaging. A patient can be injected with a small amount of 99mTc and within 24 h almost 94% of the injected radionuclide would have decayed and left the body, limiting the patient's radiation exposure. 99mTc is usually supplied to hospitals through a 99Mo/99mTc radionuclide generator system where it is produced from the β decay of the parent nuclide 99Mo (t½ = 66 h), which is produced in nuclear reactors via neutron fission. Recently, the interruption of the global supply chain of reactor-produced 99Mo, has forced the scientific community to investigate alternative production routes for 99mTc. One solution was to consider cyclotron-based methods as potential replacement of reactor-based technology and the nuclear reaction 100Mo(p,2n)99mTc emerged as the most worthwhile approach. This review reports some achievements about 99mTc produced by medical cyclotrons. In particular, the available technologies for target design, the most efficient extraction and separation procedure developed for the purification of 99mTc from the irradiated targets, the preparation of high purity 99mTc radiopharmaceuticals and the first clinical studies carried out with cyclotron produced 99mTc are described.

  6. Phyto extraction of {sup 99}Tc on soil cores with aged contamination

    Energy Technology Data Exchange (ETDEWEB)

    Massoura, S.T.; Echevarria, G.; Morel, J.L. [Institut National Polytechnique, Lab. Sols et Environnement, ENSAIA/INRA-INPL, 54 - Vandoeuvre-les-Nancy (France); Massoura, S.T.; Leclerc-Cessac, E. [Agence Nationale pour la Gestion des Dechets Radioactifs, ANDRA, 92 - Chatenay Malabry (France); Denys, D. [INERIS, 60 - Verneuil en Halatte (France)

    2004-07-01

    {sup 99}Tc is an artificial radionuclide which is found in high-activity and long-lived nuclear waste. This work was designed to study the phyto-extraction of {sup 99}Tc in soils that had received aged contamination and to monitor the resulting {sup 99}Tc concentrations in the soil solution of undisturbed soil cores in a greenhouse. Undisturbed soil cores had been sampled previously from a Rendzic Leptosol (R), a Fluvic cambisol (F) and a Dystric cambisol (D), using 0.5-m diameter PVC tubing (3 samples/soil type) without disturbing soil structure (1). Each core was equipped with two nylon porous cups (respectively 20 and 35 cm deep) and a final leachate collector. A {sup 99}TcNO{sub 3} solution had been supplied at the soil surface of each core during the two previous years (4200 kBq in total) in which maize and wheat had been successively cropped. These two crops had already removed 30-65% of total contamination before the present study. After the second year no more {sup 99}Tc was added to the cores. Thereafter, Lolium perenne was cultivated for 20 successive months. {sup 99}Tc was determined in both plant aerial parts and water samples (from both cups and collectors), and the balance of {sup 99}Tc in the system was established after phyto-extraction. Results showed that transfer of {sup 99}Tc to plants vary among soils: 7% on soil R to 11% on soil D. Concentration of {sup 99}Tc in the porous cups dramatically decreased in all soils. The plants maintained low and stable concentration levels of {sup 99}Tc in the soil solution which decreased the potential migration of the radionuclide through the cores: The leaching of {sup 99}Tc in the final collectors of the R soil cores decreased from 18 to 1.7 Bq mL{sup -1}. (author)

  7. High Volume Fraction Carbon Nanotube Composites for Aerospace Applications

    Science.gov (United States)

    Siochi, E. J.; Kim, J.-W.; Sauti, G.; Cano, R. J.; Wincheski, R. A.; Ratcliffe, J. G.; Czabaj, M.

    2016-01-01

    Reported mechanical properties of carbon nanotubes (CNTs) at the nanoscale suggest their potential to enable significantly lighter structures of interest for space applications. However, their utility depends on the retention of these properties in bulk material formats that permit practical fabrication of large structures. This presentation summarizes recent progress made to produce carbon nanotube composites with specific tensile properties that begin to rival those of carbon fiber reinforced polymer composites. CNT content in these nanocomposites was greater than 70% by weight. Tested nanocomposite specimens were fabricated from kilometers or tens of square meters of CNT, depending on the starting material format. Processing methods to yield these results, and characterization and testing to evaluate the performance of these composites will be discussed. The final objective is the demonstration of a CNT composite overwrapped pressure vessel to be flight tested in the Fall of 2016.

  8. Ti-Al Composite Wires with High Specific Strength

    OpenAIRE

    Ludwig Schultz; Jürgen Eckert; Carl-Georg Oertel; Werner Skrotzki; Ilya Okulov; Jan Romberg; Dirk Seifert; Jens Freudenberger; Juliane Scharnweber; Andy Eschke; Tom Marr; Uta Kühn; Hansjörg Klauß

    2011-01-01

    An alternative deformation technique was applied to a composite made of titanium and an aluminium alloy in order to achieve severe plastic deformation. This involves accumulative swaging and bundling. Furthermore, it allows uniform deformation of a composite material while producing a wire which can be further used easily. Detailed analysis concerning the control of the deformation process, mesostructural and microstructural features and tensile testing was carried out on the as produced wire...

  9. Autoclave cycle optimization for high performance composite parts manufacturing

    OpenAIRE

    Nele, L.; Caggiano, A.; Teti, R.

    2016-01-01

    In aeronautical production, autoclave curing of composite parts must be performed according to a specified diagram of temperature and pressure vs time. Part-tool assembly thermal inertia and shape have a large influence on the heating and cooling rate, and therefore on the dwell time within the target temperature range. When simultaneously curing diverse composite parts, the total autoclave cycle time is driven by the part-tool assembly with the lower heating and cooling rates. With the aim t...

  10. Radiolucent Composites Providing High Resistance against Sterilization Decomposition

    Czech Academy of Sciences Publication Activity Database

    Suchý, Tomáš; Balík, Karel; Sedláček, R.; Sucharda, Zbyněk; Sochor, M.; Prokop, J.; Beneš, J.; Křena, J.

    2011-01-01

    Roč. 55, č. 4 (2011), s. 401-409 ISSN 0862-5468 R&D Projects: GA ČR(CZ) GAP108/10/1457 Institutional research plan: CEZ:AV0Z30460519 Keywords : composite material * polymer matrix * radiolucency Subject RIV: JI - Composite Materials Impact factor: 0.382, year: 2011 http://www.ceramics-silikaty.cz/2011/2011_04_401.htm

  11. Architectures for High-Performance Ceramic Composites Being Improved

    Science.gov (United States)

    Yun, Hee Mann; DiCarlo, James A.

    2002-01-01

    A major thrust of the Ultra-Efficient Engine Technology (UEET) Program at the NASA Glenn Research Center is to develop advanced hot-section engine components using SiC/SiC ceramic matrix composites (CMC's) with thermostructural capability to 2400 F (1315 C). In previous studies, UEET determined that the higher the ultimate tensile strength (UTS) of the as-fabricated CMC, the greater its structural performance at 2400 F. Thus efforts have been ongoing within UEET to understand and develop fiber architecture approaches that can improve the UTS of SiC/SiC CMC's. Under UEET, SiC/SiC test panels and demonstration engine components are currently produced by the multi-ply layup of two-dimensional fabric pieces. The fabric is typically formed of multifilament tows containing high-performance Sylramic (Dow Corning) SiC fiber that is woven into two-dimensional five-harness satin fabric with 20 ends per inch in the 0 degree and 90 degree directions. In some cases, fabric pieces containing woven Sylramic fiber tows are thermally treated at NASA to form Sylramic-iBN fibers that contain a very thin in-situ-grown boron nitride layer on their surfaces. The final SiC/SiC panels and components are fabricated at the CMC vendor by compressing the fabric pieces in tools and then depositing a thin BN interphase coating on the fibers by chemical vapor deposition. The last step at the vendor is to infiltrate the BN-coated fiber architecture with SiC and silicon matrix constituents to form a dense product. Because the as-produced Sylramic fiber tows are sized with a thin polymer coating to facilitate handling and weaving, the individual fibers within the tows and fabric are in close contact with each other. This contact is further increased during fabric compression. One important recent finding is that increasing Sylramic fiber tow width in a fabric increases the UTS of the final SiC/SiC CMC. This effect is presumably related to minimizing fiber/fiber contact, which can be detrimental to

  12. High strain rate modeling of ceramics and ceramic composites

    Science.gov (United States)

    Espinosa, H. D.

    1994-07-01

    The high strain rate response of an AlN/AlN/Al composite manufactured by Lanxide Armor Products, Inc., has been studied through normal and pressure-shear plate impact experiments. Differences in the measured shear resistance, as a function of the impact configuration, motivated the examination of the material response by means of a microcracking multiple-plane model and a continuum elasto-viscoplastic constitutive model. Numerical simulations of the normal impact experiments do not support microcracking as the dominant inelastic mechanism. By contrast, an elasto-viscoplastic description of the material behavior predicts the main features of the normal stress history and the thickness dependence of the Hugoniot elastic limit. Nonetheless, the elasto-viscoplastic model cannot reproduce both the normal and pressure-shear experiments with a single set of model parameters. The inadequacy of the continuum elasto-viscoplastic model seems to result from the isotropic assumption embodied in its formulation. The shear resistance measured in the pressure-shear experiments is adequately predicted by a microcracking multiple-plane model. The agreement seems to hinge in the continuous shearing of the material on a micro-localized fashion, i.e. only one orientation becomes dominant and controls the inelastic shear deformation rate. This event does not occur in the normal impact configuration, in which the amount of inelasticity is primarily controlled by the elastic compressibility of the material. These findings explain the higher sensitivity to damage and microplasticity observed in the pressure-shear configuration, as well as the softer material response recorded in this configuration.

  13. Composite pellets of coal - Binders and high temperature testing

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, V.

    1985-01-01

    The present paper is a report on Phase III of Project B1-315, 'Technics for production and combustion of composite pellets', including environmental aspects on the method of application. Recipes were developed and tested for the following four binders: CMC, Slaggcement, water glass, and bentonite. Determinations of softening temperatures shows that all four pellet types are stable in nitrogen-atmosphere up to 1500/sup 0/C. When simulating combustion in air, softening starts at 1050 - 1200/sup 0/C, the best results being achieved with bentonite. Combusiton tests were first performed on separate pellets in order to keep conditions well within control. Very soon it showed that unsufficiently small retention of sulphur was achieved, in spite of low combustion temperature and high Ca/S-relation. As an explanation to this it was suggested that no reaction between SO/sub 2/ and CaO can be expected within pellets which still contain coal. The sulphur is presumable excaping as COS, H/sub 2/ S or elementary sulphur. These compounds do not react with CaO, but they are oxidized outside the pellets forming SO/sub 2/ which later is absorbed by CaO - containing ash. This pattern makes it less interesting to study the combustion of single pellets. So, the test programme was changed and combustion tests with bedded pellets were introduced which gave a better result. At 1050/sup 0/C lower retention was attained, possibly because the combustion was carried out too far. The burning time was long because of the low temperature.

  14. Dielectrophoretically structured piezoelectric composites with high aspect ratio piezoelectric particles inclusions

    NARCIS (Netherlands)

    Van den Ende, D.A.; Van Kempen, S.E.; Wu, X.; Groen, W.A.; Randall, C.A.; Van der Zwaag, S.

    2012-01-01

    Piezoelectric composites were prepared by dielectrophoretic alignment of high aspect ratio piezoelectric particles in a thermosetting polymer matrix. A high level of alignment was achieved in the cured composite from a resin containing randomly oriented high aspect ratio particles. Upon application

  15. The Development of High Temperature Thermoplastic Composite Materials for Additive Manufactured Autoclave Tooling

    Energy Technology Data Exchange (ETDEWEB)

    Kunc, Vlastimil [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lindahl, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hassen, Ahmed A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    In this work, ORNL and Techmer investigated and screened different high temperature thermoplastic reinforced materials to fabricate composite molds for autoclave processes using Additive Manufacturing (AM) techniques. This project directly led to the development and commercial release of two printable, high temperature composite materials available through Techmer PM. These new materials are targeted for high temperature tooling made via large scale additive manufacturing.

  16. Redox chemistry of Tc(VII)/Tc(IV) in dilute to concentrated NaCl and MgCl{sub 2} solutions

    Energy Technology Data Exchange (ETDEWEB)

    Yalcintas, Ezgi; Gaona, Xavier; Altmaier, Marcus; Geckeis, Horst [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). Inst. for Nuclear Waste Disposal; Scheinost, Andreas C. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany). Inst. of Resource Ecology; Rossendorf Beamline (ROBL) at ESRF, Grenoble (France); Kobayashi, Taishi [Kyoto Univ. (Japan). Faculty of Engineering

    2015-05-01

    The redox behaviour of Tc(VII)/Tc(IV) was investigated within the pH{sub c} range 2-14.6 in (0.5 M and 5.0 M) NaCl and (0.25 M, 2.0 M and 4.5 M) MgCl{sub 2} solutions in the presence of different reducing agents (Na{sub 2}S{sub 2}O{sub 4}, Sn(II), Fe(II)/Fe(III), Fe powder) and macroscopic amounts of Fe minerals (magnetite, mackinawite, siderite: S/L = 20-30 g L{sup -1}). In the first group of samples, the decrease of the initial Tc concentration (1 x 10{sup -5} M, as Tc(VII)) indicated the reduction to Tc(IV) according to the chemical reaction TcO{sub 4}{sup -} + 4H{sup +} + 3e{sup -} <=> TcO{sub 2} . 1.6H{sub 2}O(s) + 0.4H{sub 2}O. Redox speciation of Tc in the aqueous phase was further confirmed by solvent extraction. A good agreement is obtained between the experimentally determined Tc redox distribution and thermodynamic calculations based on NEA-TDB (Nuclear Energy Agency, Thermochemical Database) and ionic strength corrections by SIT or Pitzer approaches. These observations indicate that experimental pH{sub c} and E{sub h} values in buffered systems can be considered as reliable parameters to predict the redox behaviour of Tc in dilute to highly concentrated NaCl and MgCl{sub 2} solutions. E{sub h} of the system and aqueous concentration of Tc(IV) in equilibrium with TcO{sub 2} . 1.6H{sub 2}O(s) are strongly affected by elevated ionic strength, especially in the case of 4.5 M MgCl{sub 2} solutions. In such concentrated brines and under alkaline conditions (pH{sub c} = pH{sub max} ∝ 9), kinetics play a relevant role and thermodynamic equilibrium for the system Tc(IV)(aq) <=> Tc(IV)(s) was not attained from oversaturation conditions within the timeframe of this study (395 days). Tc(VII) is reduced to Tc(IV) by magnetite, mackinawite and siderite suspensions at pH{sub c} = 8-9 in concentrated NaCl and MgCl{sub 2} solutions. Sorption is very high in all cases (R{sub d} ≥ 10{sup 3} L kg{sup -1}), although Rd values are significantly lower in 4.5 M MgCl{sub 2

  17. Imaging endocarditis with Tc-99m-labeled antibody--an experimental study: concise communication

    Energy Technology Data Exchange (ETDEWEB)

    Wong, D.W.; Dhawan, V.K.; Tanaka, T.; Mishkin, F.S.; Reese, I.C.; Thadepalli, H.

    1982-03-01

    The sensitivity and specificity of Tc-99m-labeled antibacterial antibody (Tc-99m Ab) for detecting bacterial endocarditis were evaluated in an experimental model. Rabbit-produced antistaphylococcal antibody was extracted using Rivanol and chemically labeled with Tc-99m. This Tc-99m Ab was injected intravenously in New Zealand rabbits 24 hr after producing Staphylococcus aureus endocarditis of the aortic valve. Imaging and tissue analyses were performed on the following day. All 11 animals developed S. aureus aortic-valve vegetations and showed increased uptake of Tc-99m Ab at the aortic valve, 118 times higher than at the uninfected tricuspid valve. Although high hepatic radioactivity and anatomic uncertainties interfered with in vivo delineation of these lesions, images of the excised hearts showed all affected valves. Two rabbits inoculated with Escherichia coli did not develop endocarditis and had little uptake of Tc-99m Ab, while six rabbits with enterococcal endocarditis had no uptake of the Tc-99m Ab in their vegetations. The findings suggest potential value of Tc-99m Ab on the rapid diagnosis of endocarditis.

  18. Use of 99mTc from a commercial 99Mo/9mTc generator as yield tracer for the determination of 99Tc at low levels

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Jensen, Mikael; Nielsen, Sven Poul

    2007-01-01

    The concentrations of Tc-99 and impurity radionuclides in the Tc-99m tracer solution obtained from a commercial Mo-99/Tc-99m generator were measured by gamma spectrometry and liquid scintillation counting. Mo-99 and Ru-103 were found in the Tc-99m eluate. A simple separation using two extra alumina...

  19. Graphite-high density polyethylene laminated composites with high thermal conductivity made by filament winding

    Directory of Open Access Journals (Sweden)

    W. Lv

    2018-03-01

    Full Text Available The low thermal conductivity of polymers limits their use in numerous applications, where heat transfer is important. The two primary approaches to overcome this limitation, are to mix in other materials with high thermal conductivity, or mechanically stretch the polymers to increase their intrinsic thermal conductivity. Progress along both of these pathways has been stifled by issues associated with thermal interface resistance and manufacturing scalability respectively. Here, we report a novel polymer composite architecture that is enabled by employing typical composites manufacturing method such as filament winding with the twist that the polymer is in fiber form and the filler in form of sheets. The resulting novel architecture enables accession of the idealized effective medium composite behavior as it minimizes the interfacial resistance. The process results in neat polymer and 50 vol% graphite/polymer plates with thermal conductivity of 42 W·m–1·K–1 (similar to steel and 130 W·m–1·K–1 respectively.

  20. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2014-01-01

    Cue Rondo is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear at all...

  1. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  2. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2010-01-01

    New Year is an open composition to be realised by improvising musicians. It is included in "From the Danish Seasons" (see under this title). See more about my composition practise in the entry "Composition - General Introduction". This work is licensed under a Creative Commons "by-nc" License. You...

  3. Composition

    DEFF Research Database (Denmark)

    2014-01-01

    Memory Pieces are open compositions to be realised solo by an improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them...

  4. High Temperature Advanced Structural Composites. Volume 3. Mechanics

    Science.gov (United States)

    1993-04-02

    funcions of 00. For an incrase in temperature and stress denoted by A6, and so, we can now write do, - BAz; 6) do + b.(x; 9,) Ae, (5.1) with b,(x 9...Plasticity Theory of Fibrous Composite Materials," Metal Matriz Composites: Testig, Ana44iis, an Faiure Modes, ASTM STP 1032, W.S. Johnson, ed., American...diagraams of matriz material at various temperatures. 420 Table 1. Elastic Properties for Boron and Graphite Fibers Properties B Gr (****) E13 (MPa

  5. Measure of the magnitude of Young's modulus in whisker-like samples of the Bi-based high-Tc materials Bi sub 2 Sr sub 2 CaCu sub 2 O sub x and Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub x

    Energy Technology Data Exchange (ETDEWEB)

    Tritt, T.M.; Ehrlich, A.C.; Gillespie, D.J. (Materials Physics Branch, Naval Research Lab., Washington, DC (USA)); Marone, M.; Chen Xinfen; Skove, M.J.; Tessema, G.X. (Clemson Univ., Dept. of Physics, SC (USA)); Franck, J.P.; Jung, J. (Univ. of Alberta, Dept. of Physics, Edmonton, AB (Canada))

    1991-08-01

    We have measured Young's modulus in ribbon-like whisker samples of the high-Tc materials: Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}. This is the first direct measurement of Young's modulus for whiskers of any of the high Tc materials. We used a stress-strain probe that applies an axial force (uniaxial stress) to the whisker-like sample and simultaneously measures the corresponding sample elongation. The slope of the resulting stress-strain curve yields the magnitude of Young's modulus (Y). We found these Bi based high-Tc materials to be soft with Y {approx equal} 20 GPa for Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} and Y {approx equal} 25 GPa for Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}. (orig.).

  6. Nanostructured Composite Materials for High Temperature Thermoelectric Energy Conversion

    Science.gov (United States)

    2012-08-29

    classes of materials, half-Heusler intermetallic bulk nanocomposites and bismuth -telluride based nanocomposites; • Complete structural and...measurements K. Stokes Physics/AMRI Bismuth telluride/metallic nanoparticle composites, transport measurements J. Wiley Chemistry/AMRI Chemical...as inclusions for nanocomposites. Here, the nanoparticles are synthesized by sol-gel chemistry using hafnium(IV) tert-butoxide and ammonium hydroxide

  7. Highly Elastic and Self-Healing Composite Colloidal Gels.

    NARCIS (Netherlands)

    Diba, M.; Wang, H.; Kodger, T.E.; Parsa, S.; Leeuwenburgh, S.C.G.

    2017-01-01

    Composite colloidal gels are formed by the pH-induced electrostatic assembly of silica and gelatin nanoparticles. These injectable and moldable colloidal gels are able to withstand substantial compressive and tensile loads, and exhibit a remarkable self-healing efficiency. This study provides new,

  8. Comparative {sup 99m}Tc-MIBI, {sup 99m}Tc-tetrofosmin and {sup 99m}Tc-furifosmin uptake in human soft tissue sarcoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M.; Chehne, F.; Sinzinger, H. [Dept. of Nuclear Medicine, University Hospital, Vienna (Austria); Kalinowska, W.; Zielinski, C. [Clinical Div. of Oncology, Department of Internal Medicine I, University Hospital, Vienna (Austria)

    2000-12-01

    The uptake characteristics of technetium-99m hexakis-2-methoxyisobutylisonitrile (MIBI), {sup 99m}Tc-tetrofosmin and {sup 99m}Tc-furifosmin in human soft tissue sarcoma cell lines were investigated and compared. After 10-120 min of incubation at 37 C, 32 C and 22 C with {sup 99m}Tc-MIBI, {sup 99m}Tc-tetrofosmin and {sup 99m}Tc-furifosmin, the kinetics of cellular uptake of these tracers in human soft tissue sarcoma cells SW 684 (fibrosarcoma), SW 872 (liposarcoma), SW 982 (synovial sarcoma) and SW 1353 (chondrosarcoma) was assessed. The uptake of {sup 99m}Tc-MIBI, {sup 99m}Tc-tetrofosmin and {sup 99m}Tc-furifosmin was temperature dependent. The kinetics of uptake of {sup 99m}Tc-MIBI and of {sup 99m}Tc-tetrofosmin was similar between fibrosarcoma and liposarcoma cells, as well as between synovial sarcoma and chondrosarcoma cells. {sup 99m}Tc-furifosmin showed similar uptake kinetics in all cell lines. The uptake of {sup 99m}Tc-furifosmin was, however, significantly higher in liposarcoma than in the other cells. The data indicate that the cellular uptake of {sup 99m}Tc-MIBI, {sup 99m}Tc-tetrofosmin and {sup 99m}Tc-furifosmin is dependent on cellular metabolic activity. (orig.)

  9. {sup 99m}Tc-MDP and {sup 99m}Tc-MIBI scintimammography in patients with clinically suspicious breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Park, Chan H.; Kim, Su Zy; Yoon, Suk Nam; Park, Hee Boong [College of Medicine, Ajou Univ., Suwon (Korea, Republic of)

    1997-07-01

    around the tumor on MDP scan than MIBI scan. The sensitivity of MDP-SM for the detection of breast lesions was 90% and 57% for the lymph node lesion. There were the same in MIBI scintimammography, but the quality of MDP images was inferior to that of MIBI. {sup 99m}Tc-MDP scintimammography can demonstrate malignant breast lesions during the preoperative bone scan with a high accuracy. However, the scan quality is not as good as MIBI scintimammography.

  10. Order of amino acids in C-terminal cysteine-containing peptide-based chelators influences cellular processing and biodistribution of 99mTc-labeled recombinant Affibody molecules.

    Science.gov (United States)

    Altai, Mohamed; Wållberg, Helena; Orlova, Anna; Rosestedt, Maria; Hosseinimehr, Seyed Jalal; Tolmachev, Vladimir; Ståhl, Stefan

    2012-05-01

    Affibody molecules constitute a novel class of molecular display selected affinity proteins based on non-immunoglobulin scaffold. Preclinical investigations and pilot clinical data have demonstrated that Affibody molecules provide high contrast imaging of tumor-associated molecular targets shortly after injection. The use of cysteine-containing peptide-based chelators at the C-terminus of recombinant Affibody molecules enabled site-specific labeling with the radionuclide 99mTc. Earlier studies have demonstrated that position, composition and the order of amino acids in peptide-based chelators influence labeling stability, cellular processing and biodistribution of Affibody molecules. To investigate the influence of the amino acid order, a series of anti-HER2 Affibody molecules, containing GSGC, GEGC and GKGC chelators have been prepared and characterized. The affinity to HER2, cellular processing of 99mTc-labeled Affibody molecules and their biodistribution were investigated. These properties were compared with that of the previously studied 99mTc-labeled Affibody molecules containing GGSC, GGEC and GGKC chelators. All variants displayed picomolar affinities to HER2. The substitution of a single amino acid in the chelator had an appreciable influence on the cellular processing of 99mTc. The biodistribution of all 99mTc-labeled Affibody molecules was in general comparable, with the main difference in uptake and retention of radioactivity in excretory organs. The hepatic accumulation of radioactivity was higher for the lysine-containing chelators and the renal retention of 99mTc was significantly affected by the amino acid composition of chelators. The order of amino acids influenced renal uptake of some conjugates at 1 h after injection, but the difference decreased at later time points. Such information can be helpful for the development of other scaffold protein-based imaging and therapeutic radiolabeled conjugates.

  11. Tc-99m-EDDA-HYNIC-TOC somatostatin receptor scintigraphy in patients with carcinoids

    Directory of Open Access Journals (Sweden)

    Vlajković Marina

    2014-11-01

    Full Text Available The aim of this paper is to determine the influence of Ki-67 proliferation index on somatostatin receptor scintigraphy (SSRS with Tc-99m-EDDA-HYNIC-TOC (Tc-99m-Tektrotyd somatostatin analogue in patients with carcinoid tumors. Sixty-one patients (31 female, 30 male; age range: 33-76 years were examined: 13 patients highly suspected of having a carcinoid, and 48 patients who had undergone the surgical removal of the tumor. Whole body SSRS at 4 h postinjection, spot scintigrams and SPECT of the selected regions were obtained for all patients. Tc-99m-Tektrotyd scintigraphy was classified as true positive in 26 out of 30 and true negative in 24 out of 28 patients. The sensitivity of Tc-99mTc-Tektrotyd scintigraphy was found to be as high as 94.74% in the group of patients with low mitotic index Ki67 (20%. The likelihood of Tc-99m-Tektrotyd scan being positive when a carcinoid is present was found to be inversely proportional to the value of Ki67 proliferation index. The results showed that Tc-99m-Tektrotyd SSRS is a sensitive method for diagnosing and staging patients with well-differentiated carcinoid tumors. However, in poorly differentiated tumors with high Ki67 proliferation index, additional analyses are necessary for precise staging.

  12. Lead (Pb) column for concentration of {sup 99m}Tc-pertechnetate

    Energy Technology Data Exchange (ETDEWEB)

    Bukhari, T.H.; Khan, I.U. [Government College Univ., Lahore (Pakistan). Dept. of Chemistry; Mushtaq, A. [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Isotope Production Division

    2007-07-01

    Because of the high content of inactive molybdenum in neutron irradiated MoO{sub 3}, large columns containing alumina or gel are needed to produce chromatographic {sup 99}Mo{yields}{sup 99m}Tc generator. This results in large elution volumes containing relatively high {sup 99}Mo breakthrough and low concentrations of {sup 99m}TcO{sub 4}{sup -}. The decrease in specific volume of {sup 99m}Tc places a limitation on reconstitution of some kits for {sup 99m}Tc radiopharmaceuticals applied in diagnostic nuclear medicine. Hence concentration technique is mandatory for effective utilization of (n,{gamma}) produced {sup 99}Mo/{sup 99m}Tc generators at the start of its life whereas in case of fission {sup 99}Mo/{sup 99m}Tc generator the technique may be quite useful at the end of first week of its life. We report post elution concentration of {sup 99m}Tc using in house prepared Pb column. The high bolus volumes (10-60 ml saline) can conveniently be concentrated in {proportional_to} 1 ml of saline. (orig.)

  13. Test method development for structural characterization of fiber composites at high temperatures

    Science.gov (United States)

    Mandell, J. F.; Grande, D. H.; Edwards, B.

    1985-01-01

    Test methods used for structural characterization of polymer matrix composites can be applied to glass and ceramic matrix composites only at low temperatures. New test methods are required for tensile, compressive, and shear properties of fiber composites at high temperatures. A tensile test which should be useful to at least 1000 C has been developed and used to characterize the properties of a Nicalon/glass composite up to the matrix limiting temperature of 600 C. Longitudinal and transverse unidirectional composite data are presented and discussed.

  14. A novel {sup 99m}Tc-labeled dimethyl-substituted zoledronic acid (DMIDP) with improved bone imaging efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, L.; Lin, J.; Luo, S.; Wang, Y.; Cheng, W.; Zhang, S. [Jiangsu Institute of Nuclear Medicine, Wuxi (China). Key Laboratory of Nuclear Medicine

    2012-07-01

    A novel zoledronic acid (ZL) derivative, 1-hydroxy-2-(2,4-dimethyl-1H-imidazol-1-yl)-ethane-1,1-diyldiphosphonic acid (DMIDP, dimezoledronate), was successfully prepared and labeled with {sup 99m}Tc in a high labeling yield. The biodistribution in mice shows that {sup 99m}Tc-DMIDP has significant advantage regarding bone resorption and clearance from soft tissues compared with {sup 99m}Tc-ZL and the clinically widely-used bone-imaging agent {sup 99m}Tc-MDP (methylenediphosphonic acid). Kinetics of blood clearance displayed that distribution half-life (T{sub 1/2{alpha}}) and elimination half-life (T{sub 1/2{beta}}) of {sup 99m}Tc-DMIDP were 2.53 min and 23.53 min, while those of {sup 99m}Tc-ZL were 2.28 and 52.63 min, respectively. Excellent images of the rabbit skeleton can be quickly obtained from {sup 99m}Tc-DMIDP, which was faster than {sup 99m}Tc-ZL and {sup 99m}Tc-MDP. The present findings indicate that {sup 99m}Tc-DMIDP possesses excellent potential for application as a novel bone scanning agent. (orig.)

  15. The behavior of high-strength unidirectional composites under tension with superposed hydrostatic pressure

    NARCIS (Netherlands)

    Zinoviev, P.A.; Tsvetkov, S.V.; Kulish, G.G.; Berg, van den R.W.; Schepdael, van L.J.M.M.

    2001-01-01

    Three types of high-strength unidirectional composite materials were studied under longitudinal tension with superposed high hydrostatic pressure. Reinforcing fibers were T1000G carbon, S2 glass and Zylon PBO fibers; the Ciba 5052 epoxy resin was used as matrix. The composites were tested under

  16. Hydrogen Isotope Measurements of Organic Acids and Alcohols by Pyrolysis-GC-MS-TC-IRMS

    Science.gov (United States)

    Socki, Richard A.; Fu, Qi; Niles, Paul B.

    2011-01-01

    One possible process responsible for methane generation on Mars is abiotic formation by Fischer-Tropsch-type (FTT) synthesis during serpentinization reactions. Measurement of carbon and hydrogen isotopes of intermediary organic compounds can help constrain the origin of this methane by tracing the geochemical pathway during formation. Of particular interest within the context of this work is the isotopic composition of organic intermediaries produced on the surfaces of mineral catalysts (i.e. magnetite) during hydrothermal experiments, and the ability to make meaningful and reproducible hydrogen isotope measurements. Reported here are results of experiments to characterize the hydrogen isotope composition of low molecular weight organic acids and alcohols. The presence of these organic compounds has been suggested by others as intermeadiary products made during mineral surface catalyzed reactions. This work compliments our previous study characterizing the carbon isotope composition of similar low molecular weight intermediary organic compounds (Socki, et al, American Geophysical Union Fall meeting, Abstr. #V51B-2189, Dec., 2010). Our hydrogen isotope measurements utilize a unique analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-High Temperature Conversion-Isotope Ratio Mass Spectrometry (Py-GC-MS-TC-IRMS). Our technique is unique in that it carries a split of the pyrolyzed GC-separated product to a Thermo DSQ-II? quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of separated organic compounds, therefore both chemical and isotopic measurements can be carried out simultaneously on the same sample.

  17. High temperature tensile properties and deep drawing of fully green composites

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available In recent years, research and development of materials using biomass sources are much expected to construct a sustainable society. The so-called green composite consisting of natural fibers and biodegradable resin, is one of the most promising materials in developing biomass products. In this study, especially, we focus on the tensile deformation behavior of the green composites reinforced with ramie woven fabrics at high temperature. The results show that the fracture strain at high temperatures increases larger than that of room temperature, and initial deformation resistance of the composites seen at room temperature does not appear at high temperatures. Thus, several conditions to cause more deformability of the green composites were found. Finally, in order to utilize such deformability, Lankford-values of the green composites were clarified, and deep drawing was carried out for sheet materials made of the green composites.

  18. Performance enhancement of direct ethanol fuel cell using Nafion composites with high volume fraction of titania

    Science.gov (United States)

    Matos, B. R.; Isidoro, R. A.; Santiago, E. I.; Fonseca, F. C.

    2014-12-01

    The present study reports on the performance enhancement of direct ethanol fuel cell (DEFC) at 130 °C with Nafion-titania composite electrolytes prepared by sol-gel technique and containing high volume fractions of the ceramic phase. It is found that for high volume fractions of titania (>10 vol%) the ethanol uptake of composites is largely reduced while the proton conductivity at high-temperatures is weakly dependent on the titania content. Such tradeoff between alcohol uptake and conductivity resulted in a boost of DEFC performance at high temperatures using Nafion-titania composites with high fraction of the inorganic phase.

  19. Composition of cosmic rays at ultra high energies

    Science.gov (United States)

    Berezhko, E. G.; Knurenko, S. P.; Ksenofontov, L. T.

    2012-08-01

    We present measurements of the cosmic ray (CR) composition above 1015 eV, performed with the Yakutsk extensive air shower array. Almost 42,000 events above 1017 eV observed by Cherenkov detectors are selected for the analysis of the depth of maximum of the longitudinal development of air showers induced by CRs. The interpretation of these results in terms of CR mass composition is given. It is shown that mean logarithm of the CR atomic number is characterized by the peak value ≈ 2.5 achieved at ɛ ˜ 1017 eV and its substantial decrease within the energy interval 1017 - 1018 eV to ≈ 1 at ɛ > 1018 eV. Such a behavior can be considered as indication for the transition from galactic CR component, which is produced in galactic supernova remnants, to extragalactic CR component at ɛ = 1017 - 1018 eV.

  20. Discordant results in Tc-99m tetrofosmin and Tc-99m sestamibi parathyroid scintigraphies

    OpenAIRE

    Duarte, Paulo Schiavom; Domingues, Fernanda C.; Costa, Michele Santi; Brandão, Cynthia; Oliveira, Marco A.C. de; Vieira, José G.H.

    2007-01-01

    Parathyroid scintigraphies have been used to detect pathological parathyroid glands either before as well as after the parathyroid resection surgery in patients with hyperparathyroidism. One of the most utilized techniques to perform the studies is the double-phase images with Tc-99m sestamibi, which has been shown to be very accurate in the localization of enlarged parathyroid glands. Similar to Tc-99m sestamibi, Tc-99m tetrofosmin is a radiopharmaceutical initially developed to perform myoc...

  1. Highly energetic compositions based on functionalized carbon nanomaterials

    Science.gov (United States)

    Yan, Qi-Long; Gozin, Michael; Zhao, Feng-Qi; Cohen, Adva; Pang, Si-Ping

    2016-02-01

    In recent years, research in the field of carbon nanomaterials (CNMs), such as fullerenes, expanded graphite (EG), carbon nanotubes (CNTs), graphene, and graphene oxide (GO), has been widely used in energy storage, electronics, catalysts, and biomaterials, as well as medical applications. Regarding energy storage, one of the most important research directions is the development of CNMs as carriers of energetic components by coating or encapsulation, thus forming safer advanced nanostructures with better performances. Moreover, some CNMs can also be functionalized to become energetic additives. This review article covers updated preparation methods for the aforementioned CNMs, with a more specific orientation towards the use of these nanomaterials in energetic compositions. The effects of these functionalized CNMs on thermal decomposition, ignition, combustion and the reactivity properties of energetic compositions are significant and are discussed in detail. It has been shown that the use of functionalized CNMs in energetic compositions greatly improves their combustion performances, thermal stability and sensitivity. In particular, functionalized fullerenes, CNTs and GO are the most appropriate candidate components in nanothermites, solid propellants and gas generators, due to their superior catalytic properties as well as facile preparation methods.

  2. Composite smart materials using high-volume microelectronics fabrication techniques

    Science.gov (United States)

    Winzer, Stephen R.; Shankar, Natarajan; Caldwell, Paul J.; May, Russell G.

    1995-05-01

    Smart materials, containing sensors, actuators and processing electronics, are of great potential use in defense and commercial applications from acoustic stealth to medial imaging. While 1:3 composites using PZT rods are now available commercially in limited quantities, composites with individually addressable actuator and sensor arrays are not, nor have conditioning and processing electronics been embedded in the same material. There are several technical and cost reasons for this, including the complexity of interconnections, capacitance of individual elements, thermal dissipation, and the expense of fabricating the material. We have been developing composite materials comprising arrays of miniature actuators fabricated using surface mount capacitor technology, and amenable to automated fabrication using `pick and place' techniques. Miniature actuators with up to 0.1% strain, and operating at 30 V bias and ac swing of +/- 30 V have been fabricated, and placed in 10-by- 10 actuator arrays on Kapton sheets on which circuits have been printed. The arrays were then `potted' in RTV liquid rubbers. Individual actuator motion and multiple actuator influence functions were measured as a function of applied voltage and adjacent actuator motion. These results, along with in-water performance (source level and directivity), are presented.

  3. Technetium Removal Using Tc-Goethite Coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Wang, Guohui; Jung, Hun Bok; Peterson, Reid A.

    2013-11-18

    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Low temperature waste forms coupled with technetium removal using an alternative immobilization process such as Fe(II) treated-goethite precipitation” to increase our understanding of 99Tc long-term stability in goethite mineral form and the process that controls the 99Tc(VII) reduction and removal by the final Fe (oxy)hydroxide forms. The overall objectives of this task were to 1) evaluate the transformation process of Fe (oxy)hydroxide solids to the more crystalline goethite (α-FeOOH) mineral for 99Tc removal and 2) determine the mechanism that limits 99Tc(IV) reoxidation in Fe(II)-treated 99Tc-goethite mineral and 3) evaluate whether there is a long-term 99Tcoxidation state change for Tc sequestered in the iron solids.

  4. A high-porosity carbon molybdenum sulphide composite with enhanced electrochemical hydrogen evolution and stability

    DEFF Research Database (Denmark)

    Laursen, Anders B.; Vesborg, Peter C. K.; Chorkendorff, Ib

    2013-01-01

    This work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show an impro......This work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show...

  5. Changes in chemical composition and physico-chemical properties of chick low- and high-density lipoproteins induced by supplementation of coconut oil to the diet.

    Science.gov (United States)

    Talavera, E M; Zafra, M F; Gil-Villarino, A; Pérez, M I; Alvarez-Pez, J M; García-Peregrín, E

    1997-06-01

    Supplementation of coconut oil to the diet for 1-2 weeks produced a significant hypercholesterolemia in 14-day-old chicks. Changes in plasma fatty acid composition correlated positively with those of diets. In this study, we have shown a different response of low- and high-density lipoprotein (LDL and HDL) fractions to dietary saturated fat (coconut oil) rich in lauric and myristic acids. Although all the components of these particles seemed to increase, the percentages of increases found in total (TC), free (FC) and esterified cholesterol (EC) were higher in LDL than in HDL. TC/phospholipid (PL) ratio, considered as an inverse index of membrane fluidity, also increased with the dietary regimen in LDL, while no significant differences were found in HDL. These results suggest that supplementation of coconut oil to the diet decreased the fluidity of LDL. The EC/triglycerides (TG) ratio was also significantly increased in LDL, corroborating the main atherogenic function of this lipoprotein fraction in response to lauric and myristic acids. We have also estimated the lipidic order parameter, S, from the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH)-labelled low- and high-density lipoproteins. In LDL, temperature dependence of S shows two different behaviour zones at about 20 degrees C. In HDL, the plot of S values versus T is linear. DPH anisotropy and S increased in both LDL and HDL from treated chicks. This increase becomes more evident as temperature rises and also with dietary treatment.

  6. COMPOSITE

    African Journals Online (AJOL)

    An effective medium theory of ferroelectric ceramic-polymer composite materials which treats both components symmetrically has been investigated to demonstrate the role played by the microgeometry of inclusions on dielectric, mechanical and piezoelectric properties of 0-3 composites. The limits of the various theoretical ...

  7. Polydopamine and MnO2 core-shell composites for high-performance supercapacitors

    Science.gov (United States)

    Hou, Ding; Tao, Haisheng; Zhu, Xuezhen; Li, Maoguo

    2017-10-01

    Polydopamine and MnO2 core-shell composites (PDA@MnO2) for high-performance supercapacitors had been successfully synthesized by a facile and fast method. The morphology, crystalline phase and chemical composition of PDA@MnO2 composites are characterized using SEM, TEM, XRD, EDS and XPS. The performance of PDA@MnO2 composites are further investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy in 1 M Na2SO4 electrolyte. The PDA@MnO2 core-shell nanostructure composites exhibit a high capacitance of 193 F g-1 at the current density of 1A g-1 and retained over 81.2% of its initial capacitance after 2500 cycles of charge-discharge at 2 A g-1. The results manifest that the PDA@MnO2 composites can be potentially applied in supercapacitors.

  8. High Temperature Composites Using Schiff’s Base Pyropolymer Matrices

    Science.gov (United States)

    1988-07-15

    temperature on the AS4/T1000 material using the ASTM D3039 -76 test method. Mode I fracture toughness of AS4/T1000 was evaluated with the double cantilever beam...and Mode I fracture toughness tests. Interlaminar shear was evaluated with the ASTM D2344-76 short beam method. Testing was performed at room...Electrical Properties", Society of Plastics Engineers, April 1988, pp. 896-899. 8 NADC-88096-60 10. " Standard Tests for Toughened Resin Composites

  9. Milking technique of sup(99m)Tc generators and labeling efficiencies

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, N.; Guignard, P.A. (Royal Melbourne Hospital, Parkville (Australia). Dept. of Nuclear Medicine)

    1985-05-01

    Increased levels of /sup 99/Tc in generator produced sup(99m)Tc have an adverse effect on the labelling efficiency of red blood cells and human serum albumin. A two-step milking technique in which the first 1-2 ml of eluate is discarded has been found to produce higher and more constant labelling efficiency of lymphocytes and platelets than a one-step procedure. Binding efficiency of platelet-rich plasma and lymphocytes with sup(99m)Tc is greater in the two-step technique. High activity concentration in the eluate for critical labelling is between 1.5-3 ml.

  10. High Thermal Conductivity of Copper Matrix Composite Coatings with Highly-Aligned Graphite Nanoplatelets.

    Science.gov (United States)

    Simoncini, Alessandro; Tagliaferri, Vincenzo; Ucciardello, Nadia

    2017-10-25

    Nanocomposite coatings with highly-aligned graphite nanoplatelets in a copper matrix were successfully fabricated by electrodeposition. For the first time, the disposition and thermal conductivity of the nanofiller has been evaluated. The degree of alignment and inclination of the filling materials has been quantitatively evaluated by polarized micro-Raman spectroscopy. The room temperature values of the thermal conductivity were extracted for the graphite nanoplatelets by the dependence of the Raman G-peak frequency on the laser power excitation. Temperature dependency of the G-peak shift has been also measured. Most remarkable is the global thermal conductivity of 640 ± 20 W·m -1 ·K -1 (+57% of copper) obtained for the composite coating by the flash method. Our experimental results are accounted for by an effective medium approximation (EMA) model that considers the influence of filler geometry, orientation, and thermal conductivity inside a copper matrix.

  11. High Thermal Conductivity of Copper Matrix Composite Coatings with Highly-Aligned Graphite Nanoplatelets

    Directory of Open Access Journals (Sweden)

    Alessandro Simoncini

    2017-10-01

    Full Text Available Nanocomposite coatings with highly-aligned graphite nanoplatelets in a copper matrix were successfully fabricated by electrodeposition. For the first time, the disposition and thermal conductivity of the nanofiller has been evaluated. The degree of alignment and inclination of the filling materials has been quantitatively evaluated by polarized micro-Raman spectroscopy. The room temperature values of the thermal conductivity were extracted for the graphite nanoplatelets by the dependence of the Raman G-peak frequency on the laser power excitation. Temperature dependency of the G-peak shift has been also measured. Most remarkable is the global thermal conductivity of 640 ± 20 W·m−1·K−1 (+57% of copper obtained for the composite coating by the flash method. Our experimental results are accounted for by an effective medium approximation (EMA model that considers the influence of filler geometry, orientation, and thermal conductivity inside a copper matrix.

  12. In-service Behaviour of Flax Fibre Reinforced Composites for High Performance Applications

    OpenAIRE

    Bensadoun, Farida

    2016-01-01

    The use of flax fibres in the composites industry has been steadily growing, thanks to their good mechanical properties, manufacturing effectiveness, acoustic and thermal insulation, good vibration damping, low density and renewability. Flax fibres are a good alternative to less sustainable fibres, such as glass fibres, and they are good candidates to be used for high performance composite applications. The performance of flax fibre composites is believed to be controlled by the intrinsic pro...

  13. PREFACE: 2014 Joint IMEKO TC1-TC7-TC13 Symposium: Measurement Science Behind Safety and Security

    Science.gov (United States)

    Sousa, João A.; Ribeiro, Álvaro S.; Filipe, Eduarda

    2015-02-01

    The 2014 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium was organized by RELACRE - Portuguese Association of Accredited Laboratories and the Portuguese Society for Metrology, on 3-5 September 2014. The work of this symposium is reported in this volume. The scope of the symposium includes the main topics covered by the above Technical Committees: - TC1 Education and Training in measurement and Instrumentation - TC7 Measurement Science - TC13 Measurements in Biology and Medicine The effort towards excellence of previous events, in this well established series, is maintained. There has been a special focus on measurement science behind safety and security, with the aim of highlighting the interdisciplinary character of measurement science and the importance of metrology in our daily lives. The discussion was introduced by keynote lectures on measurement challenges in biometrics, health monitoring and social sciences, to promote useful interactions with scientists from different disciplines. The Symposium was attended by experts working in these areas from 18 countries, including USA, Japan and China, and provided a useful forum for them to share and exchange their work and ideas. In total over fifty papers are included in the volume, organized according to the presentation sessions. Each paper was independently peer-reviewed by two reviewers from a distinguished international panel. The Symposium was held in Funchal, capital of Madeira Islands, known as the Atlantic Pearl. This wonderful Atlantic archipelago, formed by Madeira and Porto Santo islands, discovered in the 14th century, was chosen to host the 2014 IMEKO TC1-TC7-TC13 Joint Symposium ''Measurement Science behind Safety and Security''. It was the first territory discovered by the Portuguese sailors, when set out to discover a new world, in an epic journey where instrumentation and quality of measurement played a central role in the success of the enterprise, and gave an

  14. Composite reinforced metallic cylinder for high speed rotation

    Science.gov (United States)

    Pradhan, Sahadev

    2017-11-01

    The objective of the present study is to design and development of the composite reinforced thin metallic cylinder to increase the peripheral speed significantly and thereby improve the separation performance in a centrifugal gas separation processes through proper optimization of the internal parameters. According to Dirac equation (Cohen (1951)), the maximum separative work for a centrifugal gas separation process increase with 4th power of the peripheral speed. Therefore, it has been intended to reinforce the metallic cylinder with composites (carbon fibers: T-700 and T- 1000 grade with suitable epoxy resin) to increase the stiffness and hoop stress so that the peripheral speed can be increased significantly, and thereby enhance the separative output. Here, we have developed the mathematical model to investigate the elastic stresses of a laminated cylinder subjected to mechanical, thermal and thermo-mechanical loading. A detailed analysis is carried out to underline the basic hypothesis of each formulation. Further, we evaluate the steady state creep response of the rotating cylinder and analyze the stresses and strain rates in the cylinder.

  15. Elemental composition of arbuscular mycorrhizal fungi at high salinity.

    Science.gov (United States)

    Hammer, Edith C; Nasr, Hafedh; Pallon, Jan; Olsson, Pål Axel; Wallander, Håkan

    2011-02-01

    We investigated the elemental composition of spores and hyphae of arbuscular mycorrhizal fungi (AMF) collected from two saline sites at the desert border in Tunisia, and of Glomus intraradices grown in vitro with or without addition of NaCl to the medium, by proton-induced X-ray emission. We compared the elemental composition of the field AMF to those of the soil and the associated plants. The spores and hyphae from the saline soils showed strongly elevated levels of Ca, Cl, Mg, Fe, Si, and K compared to their growth environment. In contrast, the spores of both the field-derived AMF and the in vitro grown G. intraradices contained lower or not elevated Na levels compared to their growth environment. This resulted in higher K:Na and Ca:Na ratios in spores than in soil, but lower than in the associated plants for the field AMF. The K:Na and Ca:Na ratios of G. intraradices grown in monoxenic cultures were also in the same range as those of the field AMF and did not change even when those ratios in the growth medium were lowered several orders of magnitude by adding NaCl. These results indicate that AMF can selectively take up elements such as K and Ca, which act as osmotic equivalents while they avoid uptake of toxic Na. This could make them important in the alleviation of salinity stress in their plant hosts.

  16. Evaluating 99mTc Auger electrons for targeted tumor radiotherapy by computational methods.

    Science.gov (United States)

    Tavares, Adriana Alexandre S; Tavares, João Manuel R S

    2010-07-01

    Technetium-99m (99mTc) has been widely used as an imaging agent but only recently has been considered for therapeutic applications. This study aims to analyze the potential use of 99mTc Auger electrons for targeted tumor radiotherapy by evaluating the DNA damage and its probability of correct repair and by studying the cellular kinetics, following 99mTc Auger electron irradiation in comparison to iodine-131 (131I) beta minus particles and astatine-211 (211At) alpha particle irradiation. Computational models were used to estimate the yield of DNA damage (fast Monte Carlo damage algorithm), the probability of correct repair (Monte Carlo excision repair algorithm), and cell kinetic effects (virtual cell radiobiology algorithm) after irradiation with the selected particles. The results obtained with the algorithms used suggested that 99mTc CKMMX (all M-shell Coster-Kroning--CK--and super-CK transitions) electrons and Auger MXY (all M-shell Auger transitions) have a therapeutic potential comparable to high linear energy transfer 211At alpha particles and higher than 131I beta minus particles. All the other 99mTc electrons had a therapeutic potential similar to 131I beta minus particles. 99mTc CKMMX electrons and Auger MXY presented a higher probability to induce apoptosis than 131I beta minus particles and a probability similar to 211At alpha particles. Based on the results here, 99mTc CKMMX electrons and Auger MXY are useful electrons for targeted tumor radiotherapy.

  17. Synthesis and biological evaluation of the four isomers of technetium-99m labeled ethylenecysteamine cysteine ({sup 99m}Tc-ECC), the mono-acid derivative of {sup 99m}tc-L,L-ethylenedicysteine

    Energy Technology Data Exchange (ETDEWEB)

    Vanbilloen, Hubert P.; Cleynhens, Bernard J.; Verbruggen, Alfons M. E-mail: alfons.verbruggen@uz.kuleuven.ac.be

    2000-02-01

    A few years ago {sup 99m}Tc-ethylenedicysteine ({sup 99m}Tc-L,L-EC) had been proposed as an interesting substitute for technetium-99m labeled mercaptoacetyltriglycine (MAG3) as renal function tracer agent. It possesses in its structure two carboxylate functions and is in this respect different from other renal tracers such as {sup 99m}Tc-N,N'-bis-(mercaptoacetyl)-2,3-diaminopropionate ({sup 99m}Tc-CO{sub 2}DADS), {sup 99m}Tc-MAG3, and Hippuran, which have only one carboxylic group. To study whether both carboxylic acid groups of {sup 99m}Tc-L,L-EC contribute to the efficient renal handling of this compound we synthesized and biologically evaluated the technetium-99m labeled isomers of L- and D-ethylenecysteamine cysteine (ECC), the mono-acid derivative of {sup 99m}Tc-L,L-EC. Labeling of L-ECC or D-ECC with {sup 99m}Tc using a direct or exchange labeling method yields for each of them two diastereomeric {sup 99m}Tc complexes (A and B, in the order of elution during reversed phase high performance liquid chromatography) in relative amounts depending on the pH during labeling. In mice, all four isomers of {sup 99m}Tc-ECC (LA, LB, DA, and DB) are cleared rapidly from the blood, mainly by the renal system. The isomers LB and DB show the most efficient renal handling, but none of the mono-acid derivatives has a urinary excretion rate as high as that of {sup 99m}Tc-L,L-EC. The renal handling of the isomers of {sup 99m}Tc-ECC is partly due to tubular secretion because the urinary excretion of these compounds is significantly lower in mice pretreated with probenecid. In the baboon, isomers DA and DB show a plasma clearance comparable to that of {sup 99m}Tc-L,L-EC. The plasma clearance of isomers LA and LB is lower but still comparable to or higher than that of {sup 99m}Tc-MAG3. In a human volunteer, isomer DB shows a plasma clearance rate only slightly lower than that of {sup 99m}Tc-L,L-EC. Thus, it appears that the presence of one carboxylate in {sup 99m}Tc

  18. Properties of high density polyethylene – Paulownia wood flour composites via injection molding

    Science.gov (United States)

    Paulownia wood (PW) flour is evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE), 25% by weight of PW, and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding followed by injection molding. Molded test composite...

  19. Rational synthesis of zerovalent iron/bamboo charcoal composites with high saturation magnetization

    Science.gov (United States)

    Mingshan Wu; Jianfeng Ma; Zhiyong Cai; Genlin Tian; Shumin Yang; Youhong Wang; Xing' e Liu

    2015-01-01

    The synthesis of magnetic biochar composites is a major new research area in advanced materials sciences. A series of magnetic bamboo charcoal composites (MBC800, MBC1000 and MBC1200) with high saturation magnetization (Ms) was fabricated in this work by mixing bamboo charcoal powder with an aqueous ferric chloride solution and subsequently...

  20. Effects of soluble organic complexants and their degradation products on the removal of selected radionuclides from high-level waste. Part 3, Distributions of Sr, Cs, Tc, Pu, and Am onto 33 absorbers from four variations of a 3:1 dilution of Hanford complexant concentrate (CC) simulant: Part 4, The effects of varying dilution ratios on the distributions of Sr, Cs, Tc, Pu, and Am onto 12 absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F. [Sandia National Labs., Albuquerque, NM (United States); Svitra, Z.V.; Bowen, S.M. [Los Alamos National Lab., NM (United States)

    1995-09-01

    Many of the radioactive waste storage tanks at USDOE facilities contain organic compounds that have been degraded by radiolysis and chemical reactions during decades of storage. Objective of this study was to measure effects of soluble organic complexants and their degradation products on sorption of Sr, Cs, Tc, Pu and Am onto 33 absorbers that in the absence of these organic compounds offer high sorption of these elements. The elements were in a generic simulant for Hanford complexant concentrate supernate that initially contained six organic complexants: EDTA, HEDTA, NTA, citrate, gluconate, and iminodiacetate. This simulant was tested as prepared and after gamma-irradiation to approximately 34 Mrads. Two other variations consisted of the unirradiated and irradiated simulants after treatment at 450C and 15,000 psi in a hydrothermal organic-destruction process. These experiments were conducted with a 3:1 water-to-simulant dilution of each of the four simulant variations. To determine effects of varying dilution ratios on the sorption of these five elements from the unirradiated and gamma-irradiated simulants that were not treated with the hydrothermal process, we measured their distribution from a 1:1 dilution, using 1 M NaOH as the diluent, onto the 12 best-performing absorbers. We then measured the sorption of these five elements from solutions having diluent-simulant ratios of 0, 0.5, 2.0, and 3.0 onto the three absorbers that performed best for sorbing Sr, Pu and Am from the 1:1 dilution. For each of 900 element/absorber/solution combinations, we measured distribution coefficients (Kd values) twice for each period for dynamic contact periods of 30 min, 2 h, and 6 h to obtain information about absorber stability and sorption kinetics. The 5400 measured Kd values indicate that the sorption of Sr, Pu, and Am is significantly decreased by the organic complexants in these simulant solutions, whereas the sorption of Cs and Tc is much less affected.

  1. Engineering of High-Toughness Carbon Nanotubes Hierarchically Laminated Composites

    Science.gov (United States)

    2012-01-27

    the design and manufacturing of high-toughness materials quite challenging. Review of the current achievements and failures in this field give strongest...reaching high values of strain, Young’s modulus, and ultimate strength, simultaneously, which makes the design and manufacturing of high-toughness...Sapelkin, A.V.; Shim, B. S.; Khomutov, G. B.; Kotov, N. A.; Sukhorukov, G. B.; Moehwald, H.; Skirtach, A. G. Carbon Nanotubes on Polymeric Microcapsules

  2. Multifunctional Magnetodielectric Composites for Antenna and High Frequency Applications

    National Research Council Canada - National Science Library

    Zhang, Xiaokai; Golt, Michael C; Ekiert, Jr., Thomas F; Yarlagadda, Shridhar; Unruh, Karl M; Xaio, John Q

    2006-01-01

    Miniaturization of high frequency antennas while maintaining desirable bandwidth, impedance, and loss characteristics has recently attracted great attention in part due to the development of metamaterials...

  3. Asialoglycoprotein-receptor-targeted hepatocyte imaging using {sup 99m}Tc galactosylated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Mi [Department of Nuclear Medicine, Research Institute of Clinical Medicine, Chonbuk National University School of Medicine, Jeonju, Jeonbuk (Korea, Republic of); Jeong, Hwan-Jeong [Department of Nuclear Medicine, Research Institute of Clinical Medicine, Chonbuk National University School of Medicine, Jeonju, Jeonbuk (Korea, Republic of)]. E-mail: jayjeong@chonbuk.ac.kr; Kim, Se-Lim [Department of Nuclear Medicine, Research Institute of Clinical Medicine, Chonbuk National University School of Medicine, Jeonju, Jeonbuk (Korea, Republic of); Sohn, Myung-Hee [Department of Nuclear Medicine, Research Institute of Clinical Medicine, Chonbuk National University School of Medicine, Jeonju, Jeonbuk (Korea, Republic of); Nah, Jae-Woon [Division of Applied Materials Engineering, Department of Polymer Science and Engineering, Sunchon National University, Sunchon, Jeonnam (Korea, Republic of); Bom, Hee-Seung [Department of Nuclear Medicine, Chonnam National University School of Medicine, Gwangju (Korea, Republic of); Park, In-Kyu [School of Agricultural Biotechnology, Seoul National University, Seoul (Korea, Republic of); Cho, Chong-Su [School of Agricultural Biotechnology, Seoul National University, Seoul (Korea, Republic of)

    2006-05-15

    This study investigated the usefulness of {sup 99m}Tc hydrazinonicotinamide-galactosylated chitosan (HGC) in hepatocyte imaging. HGC was obtained by coupling the galactose moiety of both lactobionic acid and succinimidyl 6-hydrazinonicotinate hydrochloride (succinimidyl HYNIC). The coupled product was then radiolabeled with {sup 99m}Tc using stannous chloride and tricine as reducing agent and coligand, respectively. Labeling efficiency was >90% both in room temperature and in serum up to 24 h after injection. The hepatic uptake properties of {sup 99m}Tc HGC were studied in Balb/C mice. {sup 99m}Tc HGC and {sup 99m}Tc hydrazinonicotinamide chitosan (HC) were intravenously injected into mice, with receptor binding identified by coinjection with 9 and 14 mg of free galactose. Images were acquired with a {gamma}-camera. After injection via the tail vein of the mice, {sup 99m}Tc HGC showed high selectivity for the liver, while {sup 99m}Tc HC without a galactose group showed low liver uptake. In addition, the hepatic uptake of {sup 99m}Tc HGC was blocked by coinjection of free galactose. Tissue distribution was determined at three different times (10, 60 and 120 min). The liver accumulated 13.16{+-}2.72%, 16.11{+-}5.70% and 16.55{+-}2.28% of the injected dose per gram at 10, 60 and 120 min after injection, respectively. {sup 99m}Tc HGC showed specific and rapid targeting of hepatocytes. It is a promising receptor-specific radiopharmaceutical with potential applications in liver imaging for the evaluation of hepatocytic function.

  4. Is [(99m)Tc]glucarate uptake mediated by fructose transporter GLUT-5?

    Science.gov (United States)

    Isnardi, Vanina; Clotagatide, Anthony; Bruel, Sebastien; Perek, Nathalie

    2012-11-01

    There is growing interest in the ability of [(99m)Tc]Glucarate ([(99m)Tc]GLA) to accumulate in viable tumor cells. Recent vivo studies suggest that [(99m)Tc]Glucarate could be helpful for tumor detection. Fructose transport is thought to be implicated. It is clearly established that facilitated fructose transport in tumor cells is related to the GLUT-5 transporter. This study therefore investigated whether [(99m)Tc]GLA uptake is mediated by GLUT-5 transporter. Different tumor cell lines were used. Modulation of GLUT-5 expression was assessed with and without antisense oligonucleotides directed against GLUT-5. GLUT-5 expression was assessed by indirect cell ELISA. To correlate GLUT-5 expression with tracer accumulation, [(99m)Tc]GLA uptake was determined after antisense treatment. A competition with fructose was also monitored. Inhibition of GLUT-5 expression by antisense oligonucleotides directed against GLUT-5 was effective after 24 h. An optimal of 10μM antisense oligonucleotides directed against GLUT-5 produced a 30%-40% decrease in protein expression. Modulation of [(99m)Tc]GLA uptake was monitored either by use of specific antisense oligonucleotides or by competition with fructose. Both of them produced a significant decrease of [(99m)Tc]GLA accumulation in all tested cell lines. Our results clearly demonstrate that [(99m)Tc]GLA uptake is related to GLUT-5 transporter expression and transport. In tumor imaging, [(99m)Tc]GLA may be a useful tool for non-invasive detection of malignant tumors expressing high levels of GLUT-5 transporter as, for example, breast cancers. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Direct production of 99mTc using a small medical cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Lapi, Suzanne [Washington Univ., St. Louis, MO (United States)

    2017-10-03

    This project describes an investigation towards the production of 99mTc with a small medical cyclotron. This endeavor addresses the current urgent problem of availability of 99mTc due to the ongoing production reactor failures and the upcoming Canadian reactor shut down. Currently, 99mTc is produced via nuclear fission using highly enriched uranium which is a concern due to nuclear proliferation risks. In addition to this, the United States is dependent solely on currently unreliable foreign sources of this important medical isotope. Clearly, a need exists to probe alternative production routes of 99mTc. In the first year, this project measured cross-sections and production yields of potential pathways to 99mTc and associated radionuclidic impurities produced via these pathways using a small 15 MeV medical cyclotron. During the second and third years target systems for the production of 99mTc via the most promising reaction routes were developed and separation techniques for the isolation of 99mTc from the irradiated target material will be investigated. Systems for the recycling of the enriched target isotopes as well as automated target processing systems were examined in years four and five. This project has the potential to alleviate some of the current crisis in the medical community by developing a technique to produce 99mTc on location at a university hospital. This technology will be applicable at many other sites in the United States as many other similar, low energy (<20 MeV) cyclotrons (currently used for a few hours per day for the production of [18F]fluorodeoxyglucose) are available for production of 99mTc though this method, thus leading to job creation and preservation.

  6. {sup 99m}Tc labeled VIP analog: evaluation for imaging colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P.S.; Thakur, M.L. E-mail: Mathew.Thakur@mail.tju.edu; Pallela, V.; Patti, R.; Reddy, K.; Li, H.; Sharma, S.; Pham, H.L.; Diggles, L.; Minami, C.; Marcus, C.S

    2001-05-01

    Early and reliable diagnosis of colorectal cancer continues to be demanding and challenging. Colorectal cancer cells express Vasoactive Intestinal Peptide (VIP) receptors in high density. We have prepared a VIP analog (TP3654), labeled it with {sup 99m}Tc, and evaluated it in experimental animals as an agent for imaging colorectal cancer. The tissue distribution of {sup 99m}Tc-TP3654 has been compared with that of {sup 111}In-DTPA-Octreotide and {sup 99m}Tc-anti-CEA scan in nude mice bearing human colorectal cancer LS174T. Finally, pharmacokinetic and tissue distribution studies of {sup 99m}Tc-TP3654 have been performed in four normal human volunteers. Data suggest that {sup 99m}Tc-TP3654 can be prepared efficiently without loss of its receptor specificity and biological activity. Although the 24 hr tumor uptake of {sup 99m}Tc-TP3654 in the animal model used was modest (0.21 {+-} 0.07% I.D./g), the tissue distribution profile was more favorable than that of {sup 111}In-DTPA-Octreotide or {sup 99m}Tc-anti-CEA scan. Human studies indicated that {sup 99m}Tc-TP3654 had no adverse effect in any subject. Within 24 hours, approximately 70% of the injected dose cleared through the kidneys, and approximately 20% through the hepatobiliary system. In these non-fasting volunteers hepatobiliary clearance was slow and in cancer patients tumor uptake was rapid. Data suggest that {sup 99m}Tc-TP3654 is a promising agent for imaging colorectal cancer.

  7. High temperature C/C–SiC composite by liquid silicon infiltration: a ...

    Indian Academy of Sciences (India)

    Abstract. The ceramic matrix carbon fibre (CMC) reinforced composite has received great attention for use in aerospace engineering. In aerospace, the atmosphere is highly oxidative and experiences very high temperature. In addition to this, the materials require high thermal stability and high abrasion resistance in that ...

  8. High temperature C/C–SiC composite by liquid silicon infiltration: a ...

    Indian Academy of Sciences (India)

    The ceramic matrix carbon fibre (CMC) reinforced composite has received great attention for use in aerospace engineering. In aerospace, the atmosphere is highly oxidative and experiences very high temperature. In addition to this, the materials require high thermal stability and high abrasion resistance in that atmosphere.

  9. Acute Thromboscintigraphy with 99mTc-Apcitide: Results of the Phase 3 Multicenter Clinical Trial Comparing 99mTc-Apcitide Scintigraphy with Contrast Venography for Imaging Acute DVT

    National Research Council Canada - National Science Library

    Taillefer, Raymond; Edell, Stephen; Innes, Grant; Lister-James, John

    2000-01-01

    .... ABSTRACT 99m Tc-apcitide (formerly known as 99m Tc-P280) is a radiolabeled peptide that binds with high affinity and specificity to the glycoprotein IIb/IIIa receptors expressed on the activated platelets that are involved in acute thrombosis...

  10. Acute thromboscintigraphy with (99m)Tc-apcitide: results of the phase 3 multicenter clinical trial comparing 99mTc-apcitide scintigraphy with contrast venography for imaging acute DVT. Multicenter Trial Investigators

    National Research Council Canada - National Science Library

    Taillefer, R; Edell, S; Innes, G; Lister-James, J

    2000-01-01

    (99m)Tc-apcitide (formerly known as (99m)Tc-P280) is a radiolabeled peptide that binds with high affinity and specificity to the glycoprotein IIb/IIIa receptors expressed on the activated platelets that are involved in acute thrombosis...

  11. High-speed Impact Modelling and Testing of Dyneema Composite

    NARCIS (Netherlands)

    Heru Utomo, B.D.

    2011-01-01

    Dyneema (Ultra High Molecular Weight Polyethylene – UHMW PE) is a high performance material that is used in many applications. These applications vary from leisure articles such as sails and kite wires to surgical wires and personal protection products. The reason that Dyneema outperforms many other

  12. Review of high and ultrahigh performance cementitious composites incorporating various combinations of fibers and ultrafines

    Directory of Open Access Journals (Sweden)

    M.I. Khan

    2017-10-01

    Full Text Available The outcomes of the research in modern cementitious composites have paved the way for their wide use in construction industry. The introduction of short, discontinuous and randomly distributed fibers to these composites has altered their inherent brittleness. Extensive research has been carried out on the effects of using of mono-fibers in a cementitious composite. However, limited reports in the approachable references on the use of hybrid fibers are available. The synergetic interaction between hybrid fibers have beneficial impact on cementitious composites. The incorporation of micro- and nano-pozzolanic materials, such as fly ash and silica fume have been used to develop high performance cementitious composites such as reactive powder concrete, DUCTAL and CEMTEC multiscale. Further developments were recently achieved by the development of ultra-high performance cementitious composites. The matter of developing high and ultrahigh cementitious composites using various kinds of fibers and particles has received enormous attention from the scientific community. This paper presents a comprehensive critical literature review on the area of high and ultra-high performance cement-based materials.

  13. Natural rubber/nitrile butadiene rubber/hindered phenol composites with high-damping properties

    Directory of Open Access Journals (Sweden)

    Xiuying Zhao

    2015-10-01

    Full Text Available New natural rubber (NR/nitrile butadiene rubber (NBR/hindered phenol (AO-80 composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM, polarized Fourier transform infrared spectrometer (FTIR, dynamic mechanical thermal analyzer (DMTA, and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20 composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20 composite presented a high loss factor, high area of loss peak (TA, and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing.

  14. A {sup 99m}Tc Generator using PZC for (n,{gamma}) {sup 99}Mo

    Energy Technology Data Exchange (ETDEWEB)

    Adang, H.G.; Mutalib, A.; Suparman, I.; Hamid; Purwadi, B.; Pancoko, M.; Setiowati, S.; Yulianti, V.; Robertus, D.H. [Radioisotope Production Center, National Atomic Energy Agency Kawasan PUSPIPTEK, Serpong (Indonesia)

    1998-10-01

    The high performance adsorbent Poly Zirconium Compound (PZC) was produced by Department of Radioisotope, Japan Atomic Energy Research Institute. This compound was developed as an adsorbent for natural Mo (n,{gamma}) {sup 99}Mo-{sup 99m}Tc Generator. In the present paper, we report the performance of the PZC for a {sup 99m}Tc Generator which was focused on the yield, on elution profile and {sup 99}Mo breakthrough. (author)

  15. Systematic approach to preparing ceramic-glass composites with high translucency for dental restorations.

    Science.gov (United States)

    Yoshimura, Humberto N; Chimanski, Afonso; Cesar, Paulo F

    2015-10-01

    Ceramic composites are promising materials for dental restorations. However, it is difficult to prepare highly translucent composites due to the light scattering that occurs in multiphase ceramics. The objective of this work was to verify the effectiveness of a systematic approach in designing specific glass compositions with target properties in order to prepare glass infiltrated ceramic composites with high translucency. First it was necessary to calculate from literature data the viscosity of glass at the infiltration temperature using the SciGlass software. Then, a glass composition was designed for targeted viscosity and refractive index. The glass of the system SiO2-B2O3-Al2O3-La2O3-TiO2 prepared by melting the oxide raw materials was spontaneously infiltrated into porous alumina preforms at 1200°C. The optical properties were evaluated using a refractometer and a spectrophotometer. The absorption and scattering coefficients were calculated using the Kubelka-Munk model. The light transmittance of prepared composite was significantly higher than a commercial ceramic-glass composite, due to the matching of glass and preform refractive indexes which decreased the scattering, and also to the decrease in absorption coefficient. The proposed systematic approach was efficient for development of glass infiltrated ceramic composites with high translucency, which benefits include the better aesthetic performance of the final prosthesis. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    Science.gov (United States)

    Singh, Mrityunjay

    2003-01-01

    Advanced ceramic matrix composites (CMCs) are under active consideration for use in a wide variety of high temperature applications within the aerospace, energy, and nuclear industries. The engineering designs of CMC components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in ceramic matrix composites will be presented. A wide variety of ceramic composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and mechanical properties of joints in melt infiltrated and CVI Sic matrix composites will be reported. Various joint design philosophies and design issues in joining of composites will be discussed.

  17. Urinary stone composition in Oman: with high incidence of cystinuria.

    Science.gov (United States)

    Al-Marhoon, Mohammed S; Bayoumi, Riad; Al-Farsi, Yahya; Al-Hinai, Abdullhakeem; Al-Maskary, Sultan; Venkiteswaran, Krishna; Al-Busaidi, Qassim; Mathew, Josephkunju; Rhman, Khalid; Sharif, Omar; Aquil, Shahid; Al-Hashmi, Intisar

    2015-06-01

    Urinary stones are a common problem in Oman and their composition is unknown. The aim of this study is to analyze the components of urinary stones of Omani patients and use the obtained data for future studies of etiology, treatment, and prevention. Urinary stones of 255 consecutive patients were collected at the Sultan Qaboos University Hospital. Stones were analyzed by Fourier transform infrared spectrophotometer. The biochemical, metabolic, and radiological data relating to the patients and stones were collected. The mean age was 41 years, with M:F ratio of 3.7:1. The common comorbidities associated with stone formation were hypertension; diabetes, benign prostate hyperplasia; urinary tract infection; obesity; and atrophic kidney. The common presentation was renal colic and flank pain (96%). Stones were surgically retrieved in 70% of patients. Mean stone size was 9 ± 0.5 mm (range 1.3-80). Stone formers had a BMI ≥ 25 in 56% (P = 0.006) and positive family history of stones in 3.8%. The most common stones in Oman were as follows: Calcium Oxalates 45% (114/255); Mixed calcium phosphates & calcium oxalates 22% (55/255); Uric Acid 16% (40/255); and Cystine 4% (10/255). The most common urinary stones in Oman are Calcium Oxalates. Overweight is an important risk factor associated with stone formation. The hereditary Cystine stones are three times more common in Oman than what is reported in the literature that needs further genetic studies.

  18. Ceramic Composite Mechanical Fastener System for High-Temperature Structural Assemblies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hot structures fabricated from ceramic composite materials are an attractive design option for components of future high-speed aircraft, re-entry vehicles and...

  19. High-Strength and Optically Transparent Fiber-Reinforced Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For many applications there exists a need for mechanically strong composite materials of high optical quality and transparency equivalent to window glass. One method...

  20. AVHRR Composites = Advanced Very High Resolution Radiometer U.S. Alaska: 1989 - Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Normalized Difference Vegetation Index (NDVI) Composites are produced from multiple Advanced Very High Resolution Radiometer (AVHRR) daily observations that have...

  1. Moderate doses of alcoholic beverages with dinner and postprandial high density lipoprotein composition

    NARCIS (Netherlands)

    Hendriks, H.F.J.; Veenstra, J.; Tol, A. van; Groener, J.E.M.; Schaafsma, G.

    1998-01-01

    Moderate alcohol consumption is associated with a reduced risk of coronary heart disease. In this study, postprandial changes in plasma lipids, high-density lipoprotein (HDL) composition and cholesteryl ester transfer protein (CETP) and lecithin: cholesterol acyltransferase (LCAT) activity levels

  2. 99mTc Nanocoll: a radiopharmaceutical for sentinel node localisation in breast cancer - In vitro and in vivo results

    NARCIS (Netherlands)

    Gommans, G.M.M.; Gommans, E.; van der Zant, F.M.; Teule, G.J.J.; van der Schors, T.G.; de Waard, J.W.D.

    2009-01-01

    This study evaluated labelling efficiency and radiochemical purity of 99mTc colloid albumin to identify an optimal labelling protocol for sentinel node detection. Results indicate that a 72 h eluate is not recommended for high specific labelling of 99mTc colloid albumin. Ex vivo, significantly

  3. Clinical application of TcGSA

    Energy Technology Data Exchange (ETDEWEB)

    Kokudo, Norihiro E-mail: KOKUDO-2SU@h.u-tokyo.ac.jp; Vera, David R.; Makuuchi, Masatoshi

    2003-11-01

    Asialoglycoprotein receptor (ASGP-R) is a hepatic cell surface receptor specific for galactose-terminated glycoprotein. The {sup 99m}Tc-labeled asialoglycoprotein analog, TcGSA (galactosyl-human serum albumin-diethylenetriamine-pentaacetic acid) has been applied to human hepatic receptor imaging. This method is unique and provides information that is totally independent of the ICG test or Child-Turcotte Score. However, simple parameters, HH15 or LHL15 are no better than conventional Child-Turcotte Score. Parameters obtained from kinetic modeling were useful in detecting liver cirrhosis or postoperative liver failure. They provide quantitative data on functioning liver mass. Considering the moderate cost and widespread availability of gamma cameras, a TcGSA test should be performed on patients whose liver function are not adequately estimated by an ICG test or a Child-Turcotte score.

  4. NARloy-Z-Carbon Nanotube Composites

    Science.gov (United States)

    Bhat, Biliyar N.

    2012-01-01

    Motivation: (1) NARloy-Z (Cu-3%Ag-0.5%Zr) is the state of the art, high thermal conductivity structural alloy used for making liquid rocket engine main combustion chamber liner. It has a Thermal conductivity approx 80% of pure copper. (2) Improving the thermal conductivity of NARloy-Z will help to improve the heat transfer efficiency of combustion chamber. (3)Will also help to reduce the propulsion system mass and increase performance. It will also increases thrust to weight ratio. (4) Improving heat transfer helps to design and build better thermal management systems for nuclear propulsion and other applications. Can Carbon nanotubes (CNT) help to improve the thermal conductivity (TC)of NARloy-Z? (1)CNT's have TC of approx 20X that of copper (2) 5vol% CNT could potentially double the TC of NARloy-Z if properly aligned (3) Improvement will be less if CNT s are randomly distributed, provided there is a good thermal bond between CNT and matrix. Prior research has shown poor results (1) No TC improvement in the copper-CNT composite reported (2)Reported values are typically lower (3) Attributed to high contact thermal resistance between CNT and Cu matrix (4)Results suggest that a bonding material between CNT and copper matrix is required to lower the contact thermal resistance It is hypothesized that Zr in NARloy-Z could act as a bonding agent to lower the contact thermal resistance between CNT and matrix.

  5. Residual activities of 99mTc-labelled radiopharmaceuticals in routine nuclear medicine practice.

    Science.gov (United States)

    Stavrou, Petros Z; Papachristou, Maria; Persakis, Evangelos; Kouvelis, Konstantinos; Datseris, Ioannis E

    2016-06-01

    In this study, we present a series of common Tc-labelled radiopharmaceuticals administrations performed in a busy nuclear medicine department within a 1-year timeframe in routine practice. The main objective is to identify the true activity administered to the patient and whether that is in compliance with the EANM guidelines, where applicable, and/or with the department's protocols. As a secondary objective, we aimed to assess whether the volume of the injected dose correlates to the percentage of residual activity measured after injection for each studied radiotracer. A number of commonly used Tc-labelled radiopharmaceuticals including Tc-pertechnetate, Tc-methylenediphosphonic acid, Tc-hydroxymethylenediphosphonic acid, Tc-3,3-diphosphono-1,2-propanedicarboxylic acid, Tc-dimercaptosuccinic acid (DMSA), Tc-mercaptoacetyltriglycine, Tc-2-methoxyisobutylisonitrile (sestamibi), Tc-1,2-bis[bis(2-ethoxyethyl)phosphino]ethane (tetrofosmin) and Tc-HYNIC-Tyr-octreotide (Tektrotyd) were assessed. All data were collected prospectively within a 1-year period under routine medical practice and included (a) injected activity, (b) residual activity, (c) percentage of residual activity (residual activity/injected activity×100), (d) effective activity (injected activity minus the residual activity), (e) injected volume, (f) time of injection and (g) type of procedure. In the 1837 collected measurements, the average percentage of residual activity was 13% (95% confidence interval: 12.75-13.39%). The mean effective activities were within the recommended range by the EANM guidelines, where applicable, or did not exceed the recommended doses from the department's protocols. In cases where actual injected activity was lower than the minimum suggested by the department's protocols, the imaging quality was not compromised. There was a negative correlation and thus an inverse relationship between the percentage of residual activity and administered volume for Tc-pertechnetate, Teceos

  6. Damage Assessment in Glass Fiber-Epoxy Matrix Composite under High Velocity Impact of Ice

    Directory of Open Access Journals (Sweden)

    Shokoofeh Dolati

    2013-12-01

    Full Text Available This study investigated the influence of nanoclay on the impact damage resistance of glass fiber-epoxy composites under high velocity ice impact loading. Addition of 0.5 wt. % nanoclay into epoxy was shown to improve damage resistance compared to composite plates having no nanoclay platelet. The glass fiber-epoxy composites containing nanoclay brought about substantial improvement in ice impact damage resistance and damage tolerance in the form of smaller damage area. Delamination followed by high velocity ice impact constituted major damage mode in the specimens tested.

  7. Global Failure Modes in Composite Structures for High Altitudes

    Science.gov (United States)

    Knauss, W. G.

    2004-01-01

    This report summarizes the accomplishments under the referenced grant. The work described was started under the guidance and supervision of the late Dr. James Stames as the technical contact. It was aimed at investigating the development of analysis tools to deal with the problem of rupture in reinforced structural skin of future composites-based aircraft. It was of particular interest to assess methods by which failure features reminiscent of cracks in metallic structures would develop and propagate in fiber reinforced structures in interaction with the reinforcing frame. To eventually achieve that goal it was necessary to first understand the stress or strain distribution at the front of such features so that interactions between such features and reinforcing agents could be assessed computationally. Thus the major emphasis here was on the assessment of damage front and methods on how to assess or characterize it. During the conduct of this research program Dr. Stames changed to a different NASA- internal assignment, which divorced him of the direct supervision of this grant. A student who was approximately % into the completion of his Ph.D. research needed to finish this work, and NASA funds were made available under Dr. Damodar Ambur, the successor Branch Manager for Dr. James Starnes, for the completion of this work. The current grant was the thus a new and fmal support increment for completion of the started research. Final reports for previous funding have been completed and submitted. Because of the interconnection of this last phase of the investigation with previous work it is deemed useful to make the Ph.D. thesis by Luis Gonzales the body of this report.

  8. Power Systems Development Facility Gasification Test Campaing TC18

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2005-08-31

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device (PCD), advanced syngas cleanup systems, and high pressure solids handling systems. This report details Test Campaign TC18 of the PSDF gasification process. Test campaign TC18 began on June 23, 2005, and ended on August 22, 2005, with the gasifier train accumulating 1,342 hours of operation using Powder River Basin (PRB) subbituminous coal. Some of the testing conducted included commissioning of a new recycle syngas compressor for gasifier aeration, evaluation of PCD filter elements and failsafes, testing of gas cleanup technologies, and further evaluation of solids handling equipment. At the conclusion of TC18, the PSDF gasification process had been operated for more than 7,750 hours.

  9. Power Systems Development Facility Gasification Test Campaign TC24

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-03-30

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC24, the first test campaign using a bituminous coal as the feedstock in the modified Transport Gasifier configuration. TC24 was conducted from February 16, 2008, through March 19, 2008. The PSDF gasification process operated for about 230 hours in air-blown gasification mode with about 225 tons of Utah bituminous coal feed. Operational challenges in gasifier operation were related to particle agglomeration, a large percentage of oversize coal particles, low overall gasifier solids collection efficiency, and refractory degradation in the gasifier solids collection unit. The carbon conversion and syngas heating values varied widely, with low values obtained during periods of low gasifier operating temperature. Despite the operating difficulties, several periods of steady state operation were achieved, which provided useful data for future testing. TC24 operation afforded the opportunity for testing of various types of technologies, including dry coal feeding with a developmental feeder, the Pressure Decoupled Advanced Coal (PDAC) feeder; evaluating a new hot gas filter element media configuration; and enhancing syngas cleanup with water-gas shift catalysts. During TC24, the PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane.

  10. Synthesis and evaluation of {sup 99m}Tc/{sup 99}Tc-MAG3-biotin conjugates for antibody pretargeting strategies

    Energy Technology Data Exchange (ETDEWEB)

    Gog, Frank B. van; Visser, Gerard W.M.; Gowrising, Radjish W.A.; Snow, Gordon B.; Dongen, Guus A.M.S. van E-mail: gams.vandongen@azvu.nl

    1998-10-01

    Four {sup 99m}Tc-MAG3-biotin conjugates were synthesized to determine their potential use in antibody pretargeting strategies for radioimmunoscintigraphy (RIS). To use these {sup 99m}Tc-MAG3-biotin conjugates as model compounds for {sup 186}Re-MAG3-biotin conjugates for radioimmunotherapy (RIT), nanomolar amounts of {sup 99}Tc were added as carrier to {sup 99m}Tc. The biotin derivatives used for the preparation of the conjugates - biocytin, biotin hydrazide, biotinyl-piperazine, and biotinyl-diaminosuccinic acid - differed at the site that is regarded to be susceptible to hydrolysis by biotinidase present in human plasma. All four conjugates were produced with high radiochemical purity, were stable in PBS, and demonstrated full binding capacity to streptavidin. The {sup 99m}Tc/{sup 99}Tc-MAG3-labeled biotinyl-piperazine and biotinyl-diaminosuccinic acid conjugates were stable in mouse as well as human plasma, whereas the corresponding biocytin and biotin hydrazide conjugates were rapidly degraded. The biodistribution in nude mice at 30 min after injection was similar for all conjugates, and a rapid blood clearance and high intestinal excretion were both observed. It is concluded that the metabolic routing of a conjugate containing biotin and MAG3 is dominated by these two moieties. For this reason, MAG3-biotin conjugates do not seem suited for pretargeted RIT, for which quantitative and fast renal excretion is a prerequisite to minimize radiation toxicity. However, in a pretargeted RIS approach the {sup 99m}Tc-MAG3-biotin conjugates might have potential.

  11. {sup 99}Tc in Norwegian marine environments

    Energy Technology Data Exchange (ETDEWEB)

    Kolstad, A.K.; Brown, J.; Rudjord, A.L. [Norwegian Radiation Protection Authority, Oesteraas (Norway); Straelberg, E.; Christensen, G.C. [Inst. for Energy Technology, Kjeller (Norway); Oughton, D.H. [The Agricultural Univ. og Norway, Aas (Norway)

    2002-12-01

    In February and July 1999, the {sup 99}Tc concentrations varied between 0.09 Bq m {sup -3} and 1.14 Bq m {sup -3} in the Barents Sea and in the Norwegian Sea. The highest levels of {sup 99}Tc were observed in the eastern part of the Seas. The results reflect the general circulation of water masses in the Norwegian Sea and the Barents Sea. It is evident from the seaweed data from Utsira that the discharge front from Sellafield reached Utsira waters already in the winter 1996/97.This is in agreement with seawater data from late 1996 and 1997. Sea water data from Hillesoey show a best-fit transit time of 42 months (3 years, 6 months), with an estimated uncertainty of {+-} 9 months. The transit time for {sup 99}Tc, from Sellafield to the Norwegian coastal current (Kvitsoey), is estimated to be about 3 years from the results of the Laminaria Hyperborea study. The Utsira data indicates a longer transit time, probably 3-4 years. The distribution of technetium in Laminaria Hyperborea is clearly not homogenous with the stipes containing more technetium than the leaves. The observed {sup 99}Tc concentrations in Laminaria Hyperborea from the Kvitsoey, Buskoey and Smoela are in the range 20-72 Bq kg {sup -1} (d.w.), corresponding to concentration factors of about 7,000- 9,000 Bq kg {sup 1} (d.w.)/ Bq l {sup -1} for the leaves and 11,000-17,000 Bq kg {sup 1} (d.w.)/ Bq l {sup -1} for the stems. In 1997 and 1998, the seaweed results from Utsira show an annual variation in the {sup 99}Tc concentration with a peak in the winter, but for the years 1999 and 2000 the results are however different. The observed variations may instead be related to varying seawater concentrations due to large variations in the monthly Sellafield discharges. The results of the stable analogues study for seaweed show that Re (the closest analogue to Tc) shows a slight seasonal variation, yet with peaks in the summer rather than winter months as observed for {sup 99}Tc. At Hillesoey substantial variations

  12. Antioxidant composition in cherry and high-pigment tomato cultivars.

    Science.gov (United States)

    Lenucci, Marcello S; Cadinu, Daniela; Taurino, Marco; Piro, Gabriella; Dalessandro, Giuseppe

    2006-04-05

    Fourteen cultivars of cherry tomatoes and four cultivars of high-pigment tomato hybrids were cultivated in southern Italy, and the red-ripe fruits were analyzed for their content in different classes of antioxidants and for their antioxidant activity. Among the different cultivars, significant differences were found between lycopene, beta-carotene, alpha-tocopherol, vitamin C (ascorbic acid and dehydroascorbic acid), and total phenolic and flavonoid contents. LS203 and Corbus appear to be the cultivars with the highest content of lipophilic and hydrophilic antioxidants among cherry tomatoes, respectively. All cultivars of high-pigment tomato hybrids showed an expected exceptionally high lycopene content. Among them, the highest content of lipophilic and hydrophilic antioxidants was found in cv. HLY 13. Hydrophilic and lipophilic antioxidant activities were both significantly influenced by genotype. Such results highlight an existing unexploited variability in tomato germplasm and stress the need to evaluate the biodiversity and to support conventional breeding programs to improve tomato nutritional value.

  13. Mechanism-Based Design for High-Temperature, High-Performance Composites. Book 4

    Science.gov (United States)

    1997-09-01

    Measurement of Residual Stress in Ti-6Al-4V/SiC Fiber Composites Using Cr3+ Doped Sapphire Fibers Gareth T. Munger and Haydn N. G. Wadley...SCS-6 FIBER FRACTURE IN TITANIUM MATRIX COMPOSITES David J. Sypeck and Haydn N.G. Wadley School of Engineering and Applied Science University of

  14. Strategy for addressing composition uncertainties in a Hanford high-level waste vitrification plant

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, M.F.; Piepel, G.F.

    1996-03-01

    Various requirements will be imposed on the feed material and glass produced by the high-level waste (HLW) vitrification plant at the Hanford Site. A statistical process/product control system will be used to control the melter feed composition and to check and document product quality. Two general types of uncertainty are important in HLW vitrification process/product control: model uncertainty and composition uncertainty. Model uncertainty is discussed by Hrma, Piepel, et al. (1994). Composition uncertainty includes the uncertainties inherent in estimates of feed composition and other process measurements. Because feed composition is a multivariate quantity, multivariate estimates of composition uncertainty (i.e., covariance matrices) are required. Three components of composition uncertainty will play a role in estimating and checking batch and glass attributes: batch-to-batch variability, within-batch uncertainty, and analytical uncertainty. This document reviews the techniques to be used in estimating and updating composition uncertainties and in combining these composition uncertainties with model uncertainty to yield estimates of (univariate) uncertainties associated with estimates of batch and glass properties.

  15. Limitations and pitfalls of 99mTc-EDDA/HYNIC-TOC (Tektrotyd) scintigraphy.

    Science.gov (United States)

    Garai, Ildikó; Barna, Sandor; Nagy, Gabor; Forgacs, Attila

    2016-01-01

    Tektrotyd kit was developed by Polatom company for 99mTc labeling to make an alternative tracer of somatostatin receptor scintigraphy available. Since 2005, 99mTc-EDDA/HYNIC-Tyr3-Octreotide has been used in clinical imaging and achieved high impact in management of patients with neuroendocrine tumors. Knowing the limitations and pitfalls is essential to provide ac-curate diagnosis. Therefore, the potential pitfalls associated with the use of 99mTc-EDDA/HYNIC-TOC are reviewed on the basis of own experience. Data were analyzed of 310 patients who underwent somatostatin receptor scintigraphy with 99mTc-Tektrotyd. Pitfalls during radiolabeling process or acquisition can worsen the sensitivity of SRS (somatostatin receptor scintigraphy). Recognizing physi-ological and clinical pitfalls, the diagnostic accuracy will improve.

  16. Synthesis and biological assessment of folate-accepted developer (99m)Tc-DTPA-folate-polymer.

    Science.gov (United States)

    Chen, Fei; Shao, Kejing; Zhu, Bao; Jiang, Mengjun

    2016-05-15

    A novel cancer-targetable folate-poly(2-hydroxyethyl methacrylate) (PFDH) copolymer containing DTPA segment was prepared by conventional chemical synthesis and labeled with (99m)Tc subsequently. The (99m)Tc-labled PFDH could be produced easily with high radiochemical yield of 91% and radiochemical purity of 95%. The LogP octanol-water value for the (99m)Tc-labled PFDH was -2.19 and the radiotracer was stable in phosphate-buffered saline and human serum for 2h (>95% in PBS or ∼90% in human serum). To investigate (99m)Tc-labled PFDH tumor targeting, the in vitro and in vivo stability, cell uptake, in vivo biodistribution, and SPECT imaging were evaluated, respectively. These preliminary results strongly suggest that the novel folate conjugated dendrimer maybe developed to be potential for delivery of therapeutic radionuclides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. High-Energy Impact Behaviors of Hybrid Composite Plates Strengthened with 3D-UHMWPE Composites

    Directory of Open Access Journals (Sweden)

    Sang-Youl Lee

    2018-01-01

    Full Text Available This study deals with drop-impact effects of new hybrid concrete plates strengthened with an ultrahigh molecular weight polyethylene (UHMWPE. The proposed 3D-UHMWPE results in excellent mechanical properties such as high abrasion resistance, impact strength, and low coefficient of friction. These special properties allow the product to be used in several high-performance applications. In this study, we used two kinds of high-performance materials for the impact reinforcement of a structure made of conventional materials such as a concrete. In particular, the impact mechanism of a fiber-concrete hybrid structure was studied using various parameters. The parametric studies are focused on the various effects of drop-impact on the structural performance. The combined effects of using different fiber-reinforced materials on the impact behavers are also investigated.

  18. Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites.

    Science.gov (United States)

    Shibasaki, S; Takamizawa, T; Nojiri, K; Imai, A; Tsujimoto, A; Endo, H; Suzuki, S; Suda, S; Barkmeier, W W; Latta, M A; Miyazaki, M

    The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m 3 . There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and

  19. Variation in nutrient composition and structure of high-moisture ...

    African Journals Online (AJOL)

    The morphological structure of maize observed under a scanning electron microscope showed some shrinkage of starch granules as a consequence of artificial drying temperature. In vitro digestibility of DM was improved as a result of artificial drying of high moisture maize but starch digestibility was reduced. It may be ...

  20. Diffusion Concept in Phase Stability of High Temperature Composites

    National Research Council Canada - National Science Library

    Zhao, Ji-Cheng

    2003-01-01

    A high-efficiency "diffusion multiple" approach was employed to determine the phase diagrams of nine ternary systems Nb-Ti-Si, Nb-Cr- Si, Nb-Cr-Ti, Ti-Cr-Si, Nb-Si-Al, Nb-Cr-Al, Nb-Ti-Al, Ti-Si-Al, and Ti-Cr-Al...

  1. The plasma composition of karakul lambs fed isocaloric high- and ...

    African Journals Online (AJOL)

    cogenolytic and gluconeogenic actions, whereas a high ratio would promote glycogenesis and peripheral glucose use (de. Boer et al. 1985). This lower ratio in the LF lambs may have shifted the hormonal site of glucose regulation to the liver, increasing hepatic gluconeogenesis when compared to the HF lambs. This may ...

  2. Composition.

    Science.gov (United States)

    Communication: Journalism Education Today, 2002

    2002-01-01

    Considers how photography is more than just pointing a camera in the right direction. Explains that good pictures use elements of composition such as the Rule of Thirds, leading lines, framing and repetition of shapes. Presents 16 photographs from college and secondary school publications, and describes the techniques that makes them effective.…

  3. Bulk metallic glass composite with good tensile ductility, high strength and large elastic strain limit.

    Science.gov (United States)

    Wu, Fu-Fa; Chan, K C; Jiang, Song-Shan; Chen, Shun-Hua; Wang, Gang

    2014-06-16

    Bulk metallic glasses exhibit high strength and large elastic strain limit but have no tensile ductility. However, bulk metallic glass composites reinforced by in-situ dendrites possess significantly improved toughness but at the expense of high strength and large elastic strain limit. Here, we report a bulk metallic glass composite with strong strain-hardening capability and large elastic strain limit. It was found that, by plastic predeformation, the bulk metallic glass composite can exhibit both a large elastic strain limit and high strength under tension. These unique elastic mechanical properties are attributed to the reversible B2↔B19' phase transformation and the plastic-predeformation-induced complicated stress state in the metallic glass matrix and the second phase. These findings are significant for the design and application of bulk metallic glass composites with excellent mechanical properties.

  4. STIR: Tailored Interfaces for High Strength Composites Across Strain Rates

    Science.gov (United States)

    2013-09-02

    the aramid class of fibers (Kevlar®, Twaron®) because the highly crystalline structure offers one of the highest specific toughness ratios and specific...1. Structure of an aramid (Kevlar®) fiber , showing stable aromatic carbon rings attached to backbone chains and hydrogen bonding among the chains...surface groups of the aramid fiber have been attempted with limited success. Most of these chemical enhancements focused on the attachment of

  5. Virtual Testing of Composite Structures Made of High Entropy Alloys and Steel

    Directory of Open Access Journals (Sweden)

    Victor Geantă

    2017-11-01

    Full Text Available High entropy alloys (HEA are metallic materials obtained from a mixture of at least five atomic-scale chemical elements. They are characterized by high mechanical strength, good thermal stability and hardenability. AlCrFeCoNi alloys have high compression strength and tensile strength values of 2004 MPa, respectively 1250 MPa and elongation of about 32.7%. These materials can be used to create HEA-steel type composite structures which resist to dynamic deformation during high speed impacts. The paper presents four different composite structures made from a combination of HEA and carbon steel plates, using different joining processes. The numerical simulation of the impact behavior of the composite structures was performed by virtual methods, taking into account the mechanical properties of both materials. For analyzing each constructive variant, three virtual shootings were designed, using a 7.62 × 39 mm cal. incendiary armor-piercing bullet and different impact velocities. The best ballistic behavior was provided by the composite structures obtained by welding and brazing that have good continuity and rigidity. The other composite structures, which do not have good surface adhesion, show high fragmentation risk, because the rear plate can fragment on the axis of shooting due to the combination between the shock waves and the reflected ones. The order of materials in the composite structure has a very important role in decreasing the impact energy.

  6. Evaluation of High Temperature Composites Thermal Properties under Different Heat Flux Conditions

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Bahramian

    2014-06-01

    Full Text Available The thermal protection of structures in vehicles, at instantaneous high thermal shocks, would be more effective and economically feasible among other thermal protection methods using the passive heat shields especially charring the ablative composites. The most important limitations reported are lack of compiled knowledge on designing heat shield with optimal thickness under real conditions and high surface erosion rate and low mechanical strength of char layer of a composite created by ablation process. In this paper SiAlON ceramic composites, reinforced with short carbon fiber, are identified as high performance heat shields for challenging these limitations. Ablation rate and effective thermal diffusivity at different external heat fluxes are determined and calculated using oxyacetylene flame test and modeling of temperature distributions in ablation process for evaluation of thermal protection performance and effective thermal diffusivity of this composite, as a thermal protection system. The results of this work have indicated that the carbon fiber reinforced SiAlON ceramic composite can be considered as a high ablation heat shield. Under the same condition of ablation test, SiAlON ceramic composites reinforced by carbon fiber show higher ablation performance relative to other commercial carbon fiber reinforced composite heat shields. At 8500 and 5000 kWm-2 external heat flux the ablation rates of this composite are 0.075 and 0.026 mms-1, respectively. Also, at 2500 kWm-2 external heat flux and test duration time of less than 25 s, this composite displays an adequate thermal shock protection with maximum flexural strength loss of about 23.4 %.

  7. Jasmonate-responsive expression of paclitaxel biosynthesis genes in Taxus cuspidata cultured cells is negatively regulated by the bHLH transcription factors TcJAMYC1, TcJAMYC2 and TcJAMYC4

    Directory of Open Access Journals (Sweden)

    Sangram Keshari Lenka

    2015-02-01

    Full Text Available Taxus cell suspension culture is a sustainable technology for the industrial production of paclitaxel (Taxol®, a highly modified diterpene anti-cancer agent. The methyl jasmonate (MJ-mediated paclitaxel biosynthetic pathway is not fully characterized, making metabolic engineering efforts difficult. Here, promoters of seven genes (TASY, T5αH, DBAT, DBBT, PAM, BAPT and DBTNBT, encoding enzymes of the paclitaxel biosynthetic pathway were isolated and used to drive MJ-inducible expression of a GUS reporter construct in transiently transformed Taxus cells, showing that elicitation of paclitaxel production by MJ is regulated at least in part at the level of transcription. The paclitaxel biosynthetic pathway promoters contained a large number of E-box sites (CANNTG, similar to the binding sites for the key MJ-inducible transcription factor AtMYC2 from Arabidopsis thaliana. Three MJ-inducible MYC transcription factors similar to AtMYC2 (TcJAMYC1, TcJAMYC2 and TcJAMYC4 were identified in Taxus. Transcriptional regulation of paclitaxel biosynthetic pathway promoters by transient over expression of TcJAMYC transcription factors indicated a negative rather than positive regulatory role of TcJAMYCs on paclitaxel biosynthetic gene expression.

  8. High Temperature Advanced Structural Composites. Volume 2. Ceramic Matrix Composites, Fiber Processing and Properties, and Interfaces

    Science.gov (United States)

    1993-04-02

    The obvious problems with this approach to a high melting point, creep resistance and service life are 9, n to corre for poble m temperaththe eed ct...divided by the frequency of measurement (in radians per sec ). Figure 4 shows the data for one of the load/temperature histories plotted as real (in...measurements are an exceedingly useful complement to the creep results, especially at short timescales (less than I sec .) for which creep results are

  9. Comparison of 99mTc-sestamibi-18F-fluorodeoxyglucose dual isotope simultaneous acquisition and rest-stress 99mTc-sestamibi single photon emission computed tomography for the assessment of myocardial viability.

    Science.gov (United States)

    De Boer, J; Slart, R H J A; Blanksma, P K; Willemsen, A T M; Jager, P L; Paans, A M J; Vaalburg, W; Piers, D A

    2003-03-01

    Dual isotope simultaneous acquisition single photon emission computed tomography (DISA SPECT) offers the advantage of obtaining information on myocardial perfusion using Tc-sestamibi ( Tc-MIBI) and metabolism using F-fluorodeoxyglucose ( F-FDG) in a single study. The prerequisite is that the Tc-MIBI images are not degraded by scattered 511 keV photons or poor count statistics due to the lower efficiency of the extra high energy (EHE) collimator. Therefore, we compared the registered Tc-MIBI uptake and image quality of DISA and single isotope acquisition. Furthermore, we investigated whether DISA yields additional information for the assessment of myocardial viability in comparison with rest-stress Tc-MIBI. Nineteen patients with known coronary artery disease and irreversible perfusion defects on previous rest-stress MIBI test studies were investigated. After oral glucose loading and simultaneous injection of 600 MBq of Tc-MIBI and 185 MBq of F-FDG at rest, DISA was performed using energy windows of 140 (+/-15%), 170 (+/-20%) and 511 keV (+/-15%). Planar 140 keV images were corrected for scatter by subtraction using the 170 keV window. The single and dual isotope Tc-MIBI images were both displayed in a polar map with 128 segments normalized to maximum counts. F-FDG and Tc-MIBI images were visually scored for a perfusion-metabolism mismatch pattern using nine regions per heart. There was an excellent correlation (r =0.93, PDISA does not affect the quality of the Tc-MIBI images. Furthermore, F-FDG- Tc-MIBI DISA may show viability in a small but significant (7.6%, P<0.0034) number of regions with irreversible perfusion defects on rest-stress Tc-MIBI.

  10. High frequency characterization of conductive inks embedded within a structural composite

    Science.gov (United States)

    Pa, Peter; McCauley, Raymond; Larimore, Zachary; Mills, Matthew; Yarlaggada, Shridhar; Mirotznik, Mark S.

    2015-06-01

    Woven fabric composites provide an attractive platform for integrating electromagnetic functionality—such as conformal load-bearing antennas and frequency selective surfaces—into a structural platform. One practical fabrication method for integrating conductive elements within a woven fabric composite system involves using additive manufacturing systems such as screen printing. While screen printing is an inherently scalable, flexible and cost effective method, little is known about the high frequency electrical properties of its conductive inks when they are embedded within the woven fabric composite. Thus, we have completed numerical and experimental studies to determine the electrical conductivity of screen printable conductive inks that are embedded within this composite. We have also performed mechanical studies to evaluate how printing affects the structural performance of the composite.

  11. The effect of high-level waste glass composition on spinel liquidus temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.; Riley, Brian J.; Crum, Jarrod V.; Matyas, Josef

    2014-01-15

    Spinel crystals precipitate in high-level waste glasses containing Fe, Cr, Ni , Mn, Zn, and Ru. The liquidus temperature (TL) of spinel as the primary crystallization phase is a function of glass composition and the spinel solubility (c0) is a function of both glass composition and temperature (T). Previously reported models of TL as a function of composition are based on TL measured directly, which requires laborious experimental procedures. Viewing the curve of c0 versus T as the liquidus line allows a significant broadening of the composition region for model fitting. This paper estimates TL as a function of composition based on c0 data obtained with the X-ray diffraction technique.

  12. Polyaniline/single-wall carbon nanotube (PANI/SWCNT) composites for high performance supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinay; Miura, Norio [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2006-12-01

    PANI/SWCNT composites were prepared by electrochemical polymerisation of polyaniline onto SWCNTs and their capacitive performance was evaluated by means of cyclic voltammetry and charge-discharge cycling in 1M H{sub 2}SO{sub 4} electrolyte. The PANI/SWCNT composites single electrode showed much higher specific capacitance, specific energy and specific power than pure PANI and SWCNTs. The highest specific capacitance, specific power and specific energy values of 485F/g, 228Wh/kg and 2250W/kg were observed for 73wt.% PANI deposited onto SWCNTs. PANI/SWCNT composites also showed long cyclic stability. Based upon the variations in the surface morphologies and specific capacitance of the composite, a mechanism is proposed to explain enhancement in the capacitive characteristics. The PANI/SWCNT composites have demonstrated the potential as excellent electrode materials for application in high performance supercapacitors. (author)

  13. The effect of high-level waste glass composition on spinel liquidus temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A. A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Riley, Brian J. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Crum, Jarrod V. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Hrma, Pavel [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Matyas, Josef [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2012-11-15

    Spinel crystals precipitate in high-level waste glasses containing Fe, Cr, Ni, Mn, Zn, and Ru. The liquidus temperature (T{sub L}d) of spinel as the primary crystallization phase is a function of glass composition, and the spinel solubility (c{sub o}) is a function of both glass composition and temperature (T). Previously reported models of T{sub L} as a function of composition are based on T{sub L} measured directly, which requires laborious experimental procedures. Viewing the curve of c{sub o} versus T as the liquidus line allows a significant broadening of the composition region for model fitting. This paper estimates T{sub L} as a function of composition based on c{sub o} data obtained with the X-ray diffraction technique.

  14. A fast and simple dose-calibrator-based quality control test for the radionuclidic purity of cyclotron-produced (99m)Tc.

    Science.gov (United States)

    Tanguay, J; Hou, X; Esquinas, P; Vuckovic, M; Buckley, K; Schaffer, P; Bénard, F; Ruth, T J; Celler, A

    2015-11-07

    Cyclotron production of 99mTc through the (100)Mo(p,2n)99mTc reaction channel is actively being investigated as an alternative to reactor-based (99)Mo generation by nuclear fission of (235)U. Like most radioisotope production methods, cyclotron production of 99mTc will result in creation of unwanted impurities, including Tc and non-Tc isotopes. It is important to measure the amounts of these impurities for release of cyclotron-produced 99mTc (CPTc) for clinical use. Detection of radioactive impurities will rely on measurements of their gamma (γ) emissions. Gamma spectroscopy is not suitable for this purpose because the overwhelming presence of 99mTc and the count-rate limitations of γ spectroscopy systems preclude fast and accurate measurement of small amounts of impurities. In this article we describe a simple and fast method for measuring γ emission rates from radioactive impurities in CPTc. The proposed method is similar to that used to identify (99)Mo breakthrough in generator-produced 99mTc: one dose calibrator (DC) reading of a CPTc source placed in a lead shield is followed by a second reading of the same source in air. Our experimental and theoretical analysis show that the ratio of DC readings in lead to those in air are linearly related to γ emission rates from impurities per MBq of 99mTc over a large range of clinically-relevant production conditions. We show that estimates of the γ emission rates from Tc impurities per MBq of 99mTc can be used to estimate increases in radiation dose (relative to pure 99mTc) to patients injected with CPTc-based radiopharmaceuticals. This enables establishing dosimetry-based clinical-release criteria that can be tested using commercially-available dose calibrators. We show that our approach is highly sensitive to the presence of 93gTc, 93mTc, 94gTc, 94mTc, 95mTc, 95gTc, and 96gTc, in addition to a number of non-Tc impurities.

  15. Viscosity-based high temperature waste form compositions

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, G.A.

    1994-12-31

    High-temperature waste forms such as iron-enriched basalt are proposed to immobilize and stabilize a variety of low-level wastes stored at the Idaho National Engineering Laboratory. The combination of waste and soil anticipated for the waste form results in high SiO{sub 2} + Al{sub 2}O{sub 3} producing a viscous melt in an arc furnace. Adding a flux such as CaO to adjust the basicity ratio (the molar ratio of basic to acid oxides) enables tapping the furnace without resorting to extreme temperatures, but adds to the waste volume. Improved characterization of wastes will permit adjusting the basicity ratio to between 0.7 and 1.0 by blending of wastes and/or changing the waste-soil ratio. This minimizes waste form volume. Also, lower pouring temperatures will decrease electrode and refractory attrition, reduce vaporization from the melt, and, with suitable flux, facilitate crystallization. Results of laboratory tests were favorable and pilot-scale melts are planned; however, samples have not yet been subjected to leach testing.

  16. Anatomic composition of plant tissues of highly metamorphosed coals

    Energy Technology Data Exchange (ETDEWEB)

    Kizil' shtein, L.Ya.; Shpitsgluz, A.L.

    1985-09-01

    Method is described to improve microscopic study of highly metamorphosed coals (anthracite). Study of such coals with aid of reflected polarized light is enhanced by means of ionic etching of surface of slides that enables observation not only of structures of basic microcomponents but also of finest structural details of individual cells by reflected non-polarized light. Figures illustrate results of studying many samples by ionic etching (bombing a polished surface in a vacuum with ions and pulverizing material of microcomponents to reveal heterogeneity of crystal chemistry of surface) which reveals great variety of structures of plant tissues and their component cells. Pictures of 35 slides depict gelified coal-forming plants of Donbass and central Ural coal fields; fusainized coal-forming plants of Donetsk, Gorlovsk and Tungus basins; organs of Donbass plants; structure of cells and organs of plants of Donbass. Method of ionic etching opens new perspectives for studying anatomy and histology in area of classical paleobotany by making available a large number of samples of plant material and components of highly metamorphosed coals compared with the rare samples obtained by using the polarized light method. 14 references.

  17. General report of TC 106 : Unsaturated soils

    NARCIS (Netherlands)

    Jommi, C.

    2013-01-01

    This general report summarises the contributions on unsaturated soil mechanics submitted to the Discussion Session of TC106 – Unsaturated soils –at the 18th International Conference on Soil Mechanics and Geotechnical Engineering held in Paris in September 2013. The thirty-five papers collected under

  18. High Capacity and High Voltage Composite Oxide Cathode for Li-ion Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NEI Corporation and University of Florida propose to develop a mixed metal oxide cathode that is a composite of two and three dimensional structures. At the atomic...

  19. Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

    Directory of Open Access Journals (Sweden)

    Jaqueline Albano de Morais

    Full Text Available Abstract Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate, EVA, to recover the impact resistance of high density polyethylene, HDPE, reinforced with Curauá fibers, CF. Blends and composites were processed in a corotating twin screw extruder. The pure polymers, blends and composites were characterized by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, scanning electron microscopy, tensile mechanical properties and Izod impact resistance. EVA used as impact modifier in the HDPE matrix exhibited a co-continuous phase and in the composites the fibers were homogeneously dispersed. The best combination of mechanical properties, tensile, flexural and impact, were obtained for the formulations of composites with 20 wt. % of CF and 20 to 40 wt. % of EVA. The composite prepared with 20 wt. % EVA and containing 30 wt. % of CF showed impact resistance comparable to pure HDPE and improved tensile and flexural mechanical properties.

  20. Evaluation of 99mTc-mercaptoacetyltriglycine-biocytin as a new hepatobiliary imaging agent in mice coinjected with bilirubin.

    Science.gov (United States)

    Kim, M; Seidel, J; Le, N; Kim, I S; Yoo, T M; Barker, C; Kobayashi, H; Green, M V; Carrasquillo, J A; Paik, C H

    1999-01-01

    We evaluated 99mTc-labeled mercaptoacetyltriglycine (99mTc-MAG3)-biocytin as a hepatobiliary imaging agent in the absence and presence of bilirubin in mice. We then compared its pharmacokinetic parameters; peak liver/heart activity ratio (rmax) and half clearance time (HCT) with those of 99mTc-labeled diisopropyl-iminodiacetic acid (99mTc-disofenin). Balb/c mice were injected intravenously with hepatobiliary agent (99mTc-MAG3-biocytin or 99mTc-disofenin) alone or in combination with bilirubin at two doses (7 and 14 mg/kg) dissolved in 5% human serum albumin. Images were acquired every 15 s for 30 min with a gamma-camera equipped with a pinhole collimator. Dynamic images showed rapid hepatic uptake of 99mTc-MAG3-biocytin, with rapid clearance from the blood and rapid excretion via the biliary system. Its hepatic uptake was not affected by bilirubin coinjection, whereas 99mTc-disofenin coinjected with bilirubin showed a higher blood background than 99mTc-disofenin alone. These qualitative findings were reflected in pharmacokinetic parameters, rmax and HCT. The rmax was obtained from plots of time versus liver/heart activity ratios obtained in equal-area regions of interest over the heart and liver. The HCT was calculated from the hepatic clearance curve from plots of time versus liver activity. 99mTc-MAG3-biocytin without bilirubin coinjection showed an rmax of 8.9+/-1.3 and an HCT of 399+/-36 s. These values did not change even when 14 mg/kg of bilirubin were coinjected. By contrast, the parameters for 99mTc-disofenin with bilirubin were significantly (p biocytin hepatobiliary scintigraphy in mice is not affected by bilirubin coinjection, and this hepatobiliary agent appears to offer promise for estimating hepatic function in patients with high bilirubin levels.

  1. Niobium Carbide-Reinforced Al Matrix Composites Produced by High-Energy Ball Milling

    Science.gov (United States)

    Travessa, Dilermando Nagle; Silva, Marina Judice; Cardoso, Kátia Regina

    2017-06-01

    Aluminum and its alloys are key materials for the transportation industry as they contribute to the development of lightweight structures. The dispersion of hard ceramic particles in the Al soft matrix can lead to a substantial strengthening effect, resulting in composite materials exhibiting interesting mechanical properties and inspiring their technological use in sectors like the automotive and aerospace industries. Powder metallurgy techniques are attractive to design metal matrix composites, achieving a homogeneous distribution of the reinforcement into the metal matrix. In this work, pure aluminum has been reinforced with particles of niobium carbide (NbC), an extremely hard and stable refractory ceramic. Its use as a reinforcing phase in metal matrix composites has not been deeply explored. Composite powders produced after different milling times, with 10 and 20 vol pct of NbC were produced by high-energy ball milling and characterized by scanning electron microscopy and by X-ray diffraction to establish a relationship between the milling time and size, morphology, and distribution of the particles in the composite powder. Subsequently, an Al/10 pct NbC composite powder was hot extruded into cylindrical bars. The strength of the obtained composite bars is comparable to the commercial high-strength, aeronautical-grade aluminum alloys.

  2. A New Highly Bioactive Composite for Scaffold Applications: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    Antonella Sola

    2011-01-01

    Full Text Available Hydroxyapatite (HA has been widely investigated as scaffolding material for bone tissue engineering, mainly for its excellent biocompatibility. Presently, there is an increasing interest in the composites of hydroxyapatite with bioactive glasses, with the aim to obtain systems with improved bioactivity or mechanical properties. Moreover, modifying the ratio between bioactive glass and hydroxyapatite results in the possibility of controlling the reaction rate of the composite scaffold in the human body. However, high temperature treatments are usually required in order to sinter HA-based composites, causing the bioactive glass to crystallize into a glass-ceramic, with possible negative effects on its bioactivity. In the present research work, a glass composition belonging to the Na2O-CaO-P2O5-SiO2 system, with a reduced tendency to crystallize, is applied to realize HA-based composites. The novel samples can be sintered at a relative low temperature (750 °C compared to the widely studied HA/45S5 Bioglass® composites. This fact greatly helps to preserve the amorphous nature of the glass, with excellent effects in terms of bioactivity, according to in vitro tests. As a first application, the obtained composites are also tested to realize highly porous scaffolds by means of the standard burning out method.

  3. Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder.

    Science.gov (United States)

    Xiong, Yabo; Huang, Shaoyun; Wang, Wenqi; Liu, Xinghai; Li, Houbin

    2017-11-29

    Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced (p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications.

  4. Simulation of Impact Phenomena on the Composite Structures Containing Ceramic Plates and High Entropy Alloys

    Science.gov (United States)

    Geantă, V.; Cherecheș, T.; Lixandru, P.; Voiculescu, I.; Ștefănoiu, R.; Dragnea, D.; Zecheru, T.; Matache, L.

    2017-06-01

    Due to excellent mechanical properties, high entropy alloys from the system AlxCrFeCoNi can be used successfully to create composite structures containing both metallic and ceramic plates, which resists at dynamic load during high speeds impact (like projectiles, explosion). The paper presents four different composite structures made from a combination of metallic materials and ceramics plates: duralumin-ceramics, duralumin-ceramics-HEA, HEA-ceramics-HEA, HEA-ceramics-duralumin. Numerical simulation of impact behavior of the composite structures was performed by virtual methods, taking into account the mechanical properties of both materials. The best results were obtained using composite structures HEA-ceramics-HEA, HEA-ceramics-duralumin.

  5. A review of recent developments in joining high-performance thermoplastic composites

    Science.gov (United States)

    Cole, K. C.

    1991-06-01

    There is currently a great deal of interest in the use of thermoplastic polymers as matrices in fiber reinforced composites for high performance applications, such as those encountered in the aerospace industry. These materials include polyether ether ketone (PEEK), polyphenylene sulphide (PPS), polyetherimide (PEI), polyamideimide (PAI), polyamides, polyimides, and polysulphones. A literature review is provided on the different ways of joining high performance thermoplastic composites by adhesive and fusion bonding. The discussion on adhesive bonding includes examination of the performance of specific adhesive/thermoplastic combinations and of techniques for the preparation of composite surfaces: abrasion, etching, flame, and plasma treatments. Thermoplastic composite welding techniques discussed in depth include the following: heated press welding, resistance welding, induction welding, and ultrasonic welding. Works which examine or compare applications for these bonding techniques are also reviewed.

  6. Hierarchical nanoreinforced composites for highly reliable large wind turbines: Computational modelling and optimization

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon

    2014-01-01

    , with modified, hybridor nanomodified structures. In this project, we seek to explore the potential of hybrid (carbon/glass),nanoreinforced and hierarchical composites (with secondary CNT, graphene or nanoclay reinforcement) as future materials for highly reliable large wind turbines. Using 3D multiscale...... computational models ofthe composites, we study the effect of hybrid structure and of nanomodifications on the strength, lifetime and service properties of the materials (see Figure 1). As a result, a series of recommendations toward the improvement of composites for structural applications under long term...

  7. Characterization and modeling of performance of Polymer Composites Reinforced with Highly Non-Linear Cellulosic Fibers

    Science.gov (United States)

    Rozite, L.; Joffe, R.; Varna, J.; Nyström, B.

    2012-02-01

    The behaviour of highly non-linear cellulosic fibers and their composite is characterized. Micro-mechanisms occurring in these materials are identified. Mechanical properties of regenerated cellulose fibers and composites are obtained using simple tensile test. Material visco-plastic and visco-elastic properties are analyzed using creep tests. Two bio-based resins are used in this study - Tribest and EpoBioX. The glass and flax fiber composites are used as reference materials to compare with Cordenka fiber laminates.

  8. Preparation and evaluation of hydrous titanium oxide as a high affinity adsorbent for molybdenum ({sup 99}Mo) and its potential for use in {sup 99m}Tc generators

    Energy Technology Data Exchange (ETDEWEB)

    Qazi, Q.M.; Mushtaq, A. [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Isotope Production Div.

    2011-07-01

    Hydrous titanium oxide was prepared and its affinity as an adsorbent for molybdenum ({sup 99}Mo) and its potential for use in {sup 99m}Tc generators were evaluated. Adsorption behavior of molybdate on hydrous titanium oxide was studied at boiling water bath temperature ({proportional_to} 100 C) using radiotracer technique. Various parameters affecting the adsorption of molybdenum, such as pH, amount of molybdenum, incubation period etc., were determined. Technetium-99m generators were prepared by adsorbing low specific activity Molybdenum-99 ({proportional_to} 230 mg) on 1 g hydrous titanium oxide. Elutions were carried out with normal saline. Performance of the generators, such as {sup 99}Mo breakthrough, titanium content, pH, elution profile, radiochemical purity and labeling efficiency of kits, was checked. (orig.)

  9. Dose calibrator linearity test: 99mTc versus 18F radioisotopes*

    Science.gov (United States)

    Willegaignon, José; Sapienza, Marcelo Tatit; Coura-Filho, George Barberio; Garcez, Alexandre Teles; Alves, Carlos Eduardo Gonzalez Ribeiro; Cardona, Marissa Anabel Rivera; Gutterres, Ricardo Fraga; Buchpiguel, Carlos Alberto

    2015-01-01

    Objective The present study was aimed at evaluating the viability of replacing 18F with 99mTc in dose calibrator linearity testing. Materials and Methods The test was performed with sources of 99mTc (62 GBq) and 18F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical 99mTc and 18F sources activities were calculated and subsequently compared. Results Mean deviations between experimental and theoretical 99mTc and 18F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the 99mTc source as measured with the equipment pre-calibrated to measure 99mTc and 18F was 3.42 (± 0.06), and for the 18F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. Conclusion The results of the linearity test using 99mTc were compatible with those obtained with the 18F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in 18F acquisition suggest 99mTc as the element of choice to perform dose calibrator linearity tests in centers that use 18F, without any detriment to the procedure as well as to the quality of the nuclear medicine service. PMID:25798005

  10. Mass estimate and close approaches of near-Earth asteroid 2015 TC25

    Science.gov (United States)

    Farnocchia, Davide; Tholen, David J.; Micheli, Marco; Ryan, William; Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Giorgini, Jon D.

    2017-10-01

    Near-Earth asteroid 2015 TC25 was discovered by the Catalina Sky Survey in October 2015, just two days before an Earth flyby at 0.3 lunar distances. By using ground-based optical, near-infrared, and radar assets during the flyby, Reddy et al. (2016) successfully characterized 2015 TC25. They suggested that the object has a high albedo and a diameter of 2 m, which makes 2015 TC25 one of the smallest asteroids ever detected. Moreover, the orbital information available at the end of the 2015 apparition indicated that 2015 TC25 had a probability of an Earth impact of more than 1 in 10000 from 2070 to 2115. To rule out possible impacts we recovered 2015 TC25 at the end of March 2017 and continued tracking the object through the end of April, when it became too faint to be observable. The recent 2017 astrometry clearly shows the action of solar radiation pressure on the orbit of 2015 TC25 with a 7.6-sigma detection. This solar radiation pressure estimate allows us to put constraints on the density and mass of 2015 TC25 and further suggests that the object is only a couple of meters in size. In particular, the area-to-mass ratio is between 0.6 m^2/t and 0.7 m^2/t and, for a diameter of 2 m, the density is about 1.1 g/cm^3. By accounting for the contribution of non-gravitational perturbations, we analyze the future trajectory of 2015 TC25. Based on the extended data arc, ephemeris predictions are now deterministic until the Earth close approach in 2089 and a Monte Carlo search rules out impacts for the next 100 years.

  11. Dose calibrator linearity test: {sup 99m}Tc versus {sup 18}F radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Willegaignon, Jose; Coura-Filho, George Barberio; Garcez, Alexandre Teles, E-mail: willegaignon@hotmail.com [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil); Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Fac. de Medicina; Alves, Carlos Eduardo Gonzalez Ribeiro; Cardona, Marissa Anabel Rivera; Gutterres, Ricardo Fraga [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2015-01-15

    Objective: the present study was aimed at evaluating the viability of replacing {sup 18}F with {sup 99m}Tc in dose calibrator linearity testing. Materials and methods: the test was performed with sources of {sup 99m}Tc (62 GBq) and {sup 18}F (12 GBq) whose activities were measured up to values lower than 1 MBq. Ratios and deviations between experimental and theoretical {sup 99m}Tc and {sup 18}F sources activities were calculated and subsequently compared. Results: mean deviations between experimental and theoretical {sup 99m}Tc and {sup 18}F sources activities were 0.56 (± 1.79)% and 0.92 (± 1.19)%, respectively. The mean ratio between activities indicated by the device for the {sup 99m}Tc source as measured with the equipment precalibrated to measure {sup 99m}Tc and {sup 18}F was 3.42 (± 0.06), and for the {sup 18}F source this ratio was 3.39 (± 0.05), values considered constant over the measurement time. Conclusion: the results of the linearity test using {sup 99m}Tc were compatible with those obtained with the {sup 18}F source, indicating the viability of utilizing both radioisotopes in dose calibrator linearity testing. Such information in association with the high potential of radiation exposure and costs involved in {sup 18}F acquisition suggest {sup 99m}Tc as the element of choice to perform dose calibrator linearity tests in centers that use {sup 18}F, without any detriment to the procedure as well as to the quality of the nuclear medicine service. (author)

  12. High-Performance Supercapacitor Electrode Based on Buckypaper/Polyaniline Composite

    Science.gov (United States)

    Tran, Toan Phuoc; Do, Quyet Huu

    2017-10-01

    Polyaniline (PANI) was coated on carbon nanotubes within a nanoporous sheet (buckypaper) by in situ electrochemical polymerization. The chemical structure and morphology of the polyaniline and the resulting composites were studied. This work shows a strong effect of aniline concentration and buckypaper soaking time on the synthesis of polyaniline. Outstanding composite areal and gravimetric capacitances of 54 F/cm2 and 400 F g-1, respectively, could be achieved at high weight loading of PANI.

  13. Mechanical and thermal properties of high density polyethylene - dried distillers grains with solubles composites

    OpenAIRE

    Brent Tisserat; Louis Reifschneider; Rogers Harry O’Kuru; Victoria L. Finkenstadt

    2013-01-01

    Dried Distillers Grain with Solubles (DDGS) was evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE) composed of 25% by weight DDGS and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding and injection molding. An improved DDGS bio-filler was produced by solvent treating DDGS (STDDGS). Injection-molded test specimens were evaluated for their tensile, flexural, impact, and thermal properties. Composite blends...

  14. Advanced thermoplastic composites: An attractive new material for usage in highly loaded vehicle components

    Energy Technology Data Exchange (ETDEWEB)

    Mehn, R.; Seidl, F.; Peis, R.; Heinzmann, D.; Frei, P. [BMW AG Muenchen (Germany)

    1995-10-01

    Beside the lightweight potential and further well known advantages of advanced composite materials, continuous fiber reinforced thermoplastics employed in vehicle structural parts especially offer short manufacturing cycle times and an additional economically viable manufacturing process. Presenting a frame structure concept for two highly loaded vehicle parts, a safety seat and a side door, numerous features concerning the choice of suitable composite materials, design aspects, investigations to develop a thermoforming technique, mature for a series production of vehicle parts, are discussed.

  15. Reactive Processing and Co-Extrusion of Ultra-High Temperature Ceramics and Composites

    Science.gov (United States)

    2006-02-28

    Faenza, Italy. Ultra-high temperature ceramics (UHTCs) are a unique class of materials with melting temperatures in excess of 3000’C. The borides ...composites with silicon carbide (SiC) and molybdenum disilicide (MoSi 2) were examined. Two main approaches were pursued: 1) the use of reactive processing...Diboride- Molybdenum Disilicide Ceramics," pp. 299-308 in Advances in Ceramic Matrix Composites IX, Ceramic Transactions, Volume 153, ed. by N.P. Bansal, J.P

  16. Apollo 17 high-Ti mare basalts - New bulk compositional data, magma types, and petrogenesis

    Science.gov (United States)

    Warner, R. D.; Taylor, G. J.; Conrad, G. H.; Northrop, H. R.; Barker, S.; Keil, K.; Ma, M.-S.; Schmitt, R.

    1979-01-01

    Bulk compositional and mineral chemical data for 28 previously unanalyzed samples support the classification of Apollo-17 high-Ti mare basalts into three-types (A, B, and C), defined on the basis of analyses of fine-grained basalts. The most MgO- and TiO2-rich fine-grained basalts of these types appear to be the best choices for representing the compositions of the parent magmas.

  17. Enhanced electroactive response of unidirectional elastomeric composites with high-dielectric-constant fibers.

    Science.gov (United States)

    Subramani, Krishna Bala; Cakmak, Enes; Spontak, Richard J; Ghosh, Tushar K

    2014-05-01

    A fiber-elastomer composite design with a vastly improved and directional actuation response is proposed for dielectric elastomer actuators. The all-elastomer composites are capable of achieving remarkably high actuation stresses, directional strains, electromechanical coupling efficiencies, and energy densities at relatively low electric fields. Their electromechanical metrics are among the highest reported for this class of electroactive materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Sorption Isotherm of Southern Yellow Pine—High Density Polyethylene Composites

    OpenAIRE

    Feihong Liu; Guangping Han; Wanli Cheng,; Qinglin Wu

    2015-01-01

    Temperature and relative humidity (RH) are two major external factors, which affect equilibrium moisture content (EMC) of wood-plastic composites (WPCs). In this study, the effect of different durability treatments on sorption and desorption isotherms of southern yellow pine (SYP)-high density polyethylene (HDPE) composites was investigated. All samples were equilibriumed at 20 °C and various RHs including 16%, 33%, 45%, 66%, 75%, 85%, 93%, and100%. EMCs obtained from desorption and absorpt...

  19. Thymidine kinase enzyme selective imaging radiopharmaceutical. {sup 99m}Tc(CO){sub 3}-Ganciclovir

    Energy Technology Data Exchange (ETDEWEB)

    Gedik, B.; Teksoez, S.; Ichedef, C.; Kilcar, A.Y.; Medine, E.I.; Ucar, E. [Ege Univ., Bornova, Izmir (Turkey). Dept. of Nuclear Applications

    2013-03-01

    The aim of this study is to radiolabel Ganciclovir, known as having selective antiviral properties against thymidine kinase, with technetium tricarbonylcore ({sup 99m}Tc(CO){sub 3}{sup +}) and to investigate the biological behavior of this complex in vitro and in vivo. Commercially provided Ganciclovir (GCV) was radiolabeled with {sup 99m}Tc(CO){sub 3}{sup +}. Initially, optimum radiolabeling conditions were determined by analyzing factors such as temperature, pH and time. Quality control of the radiolabeled compound was performed. The radiolabeling yield was found to be 97%. The {sup 99m}Tc(CO){sub 3}-GCV complex also displayed good in vitro stability during the 24 h period. In vitro cell uptake studies showed that the {sup 99m}Tc(CO){sub 3}-GCV complex is highly uptaken in A-549, PC-3, HeLa cell lines according to the control group {sup 99m}Tc(I)-tricarbonyl core. The knowledge gained from in vivo and in vitro studies of {sup 99m}Tc(CO){sub 3}-GCV could contribute to the development of a new HSV1-tk gene imaging agent. (orig.)

  20. Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)

    Science.gov (United States)

    Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

    2011-09-01

    99Technetium ( 99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life ( t1/2 = 2.13 × 10 5 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron, either in aqueous form (Fe 2+) or in mineral form [Fe(II)], has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) has not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Surface Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total structural Fe content of these clay minerals, after surface Fe-oxide removal, ranged from 0.7% to 30.4% by weight, and the structural Fe(III)/Fe(total) ratio ranged from 45% to 98%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with structural Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella putrefaciens CN32 cells as a mediator. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. In the S-I series, smectite (montmorillonite) was the most reducible (18% and 41% without and with AQDS, respectively) and illite the least (1% for both

  1. Th1 Th2, Tc1 Tc2 cells of patients with otolaryngological diseases

    Directory of Open Access Journals (Sweden)

    Nobuo Ohta

    2004-01-01

    Full Text Available Cytokines are important regulatory mediators secreted by T cells and other immunoactive cells. Based on the cytokine synthesis patterns, CD4 T cells can often be classified into at least two populations with different immune regulatory functions. The Th1 cells, producing interleukin (IL-2 and interferon (IFN-γ, are often associated with cell-mediated immune responses such as delayed type hypersensitivity (DTH, whereas Th2 cells, secreting IL-4, IL-5 and IL-13, usually provide B cell help and enhance allergic reactions. Naïve CD8 T cells, similar to CD4 T cells, can differentiate into at least two subsets of cytolytic effector cells with distinct cytokine patterns. The Tc1 cells secrete a Th 1 - like cytokine pattern, including IL-2 and IFN-γ. The Tc2 cells produce Th2 cytokines, including IL-4, IL-5 and 11—10. There is increasing evidence that Th1/Th2 and Tc1/Tc2 cytokine imbalance has been of patho- genetic importance in various diseases, such as allergic and autoimmune diseases. The present review article focuses on the evidence that the imbalance of Th1/Th2 and Tc1/Tc2 cytokines plays an important role in various otolaryngological diseases, such as Kimura's disease, Wegener's granulomatosism, acute perceptive hearing loss and Meniere's disease. It is concluded that the predominance of Th 1 or Th2 and Tc1 or Tc2 cells may contribute to the mechanism in the pathogenesis of these otolaryngological diseases.

  2. Joining and Assembly of Silicon Carbide-based Advanced Ceramics and Composites for High Temperature Applications

    Science.gov (United States)

    Singh, M.

    2004-01-01

    Silicon carbide based advanced ceramics and fiber reinforced composites are under active consideration for use in wide variety of high temperature applications within the aeronautics, space transportation, energy, and nuclear industries. The engineering designs of ceramic and composite component require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. In addition these components have to be joined or assembled with metallic sub-components. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing o high temperature joints in ceramic matrix composites will be presented. Silicon carbide based advanced ceramics (CVD and hot pressed), and C/SiC and SiC/SiC composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and high temperature mechanical properties of joints in silicon carbide ceramics and CVI and melt infiltrated SiC matrix composites will,be reported. Various joint design philosophies and design issues in joining of ceramics and composites well be discussed.

  3. Monte Carlo simulations for optimum design of composite detectors for high energy gamma ray

    CERN Document Server

    Wen Wan Xin

    2002-01-01

    The efficiencies of clover and cluster composite detectors using NaI and BGO crystals as the media for detection of high energy gamma ray are systematically simulated with Monte Carlo method. It is shown that for the same geometry of detection media concerned the efficiency of the composite BGO detector is much higher than that of the composite NaI detector. Therefore NaI crystal is not a suitable medium of composite detectors for high energy gamma ray duo to low efficiency. Doppler broadening and distortion to gamma spectrum in comparison with BGO crystal. The composite BGO detectors have many advantages such as large photopeak efficiency, small Doppler effect and regular gamma spectrum. As to the clover and cluster composite detectors consisting of the cylinders of BGO crystal with original size phi 76 x 127, the intrinsic photopeak efficiencies are over 40% and the enhanced factor of absolute efficiencies is as high as 2.4 and 2.7, respectively, for 22 MeV gamma ray

  4. Understanding the in vivo uptake kinetics of a phosphatidylethanolamine-binding agent (99m)Tc-Duramycin.

    Science.gov (United States)

    Audi, Said; Li, Zhixin; Capacete, Joseph; Liu, Yu; Fang, Wei; Shu, Laura G; Zhao, Ming

    2012-08-01

    (99m)Tc-Duramycin is a peptide-based molecular probe that binds specifically to phosphatidylethanolamine (PE). The goal was to characterize the kinetics of molecular interactions between (99m)Tc-Duramycin and the target tissue. High level of accessible PE is induced in cardiac tissues by myocardial ischemia (30 min) and reperfusion (120 min) in Sprague-Dawley rats. Target binding and biodistribution of (99m)Tc-duramycin were captured using SPECT/CT. To quantify the binding kinetics, the presence of radioactivity in ischemic versus normal cardiac tissues was measured by gamma counting at 3, 10, 20, 60 and 180 min after injection. A partially inactivated form of (99m)Tc-Duramycin was analyzed in the same fashion. A compartment model was developed to quantify the uptake kinetics of (99m)Tc-Duramycin in normal and ischemic myocardial tissue. (99m)Tc-duramycin binds avidly to the damaged tissue with a high target-to-background radio. Compartment modeling shows that accessibility of binding sites in myocardial tissue to (99m)Tc-Duramycin is not a limiting factor and the rate constant of target binding in the target tissue is at 2.2 ml/nmol/min/g. The number of available binding sites for (99m)Tc-Duramycin in ischemic myocardium was estimated at 0.14 nmol/g. Covalent modification of D15 resulted in a 9-fold reduction in binding affinity. (99m)Tc-Duramycin accumulates avidly in target tissues in a PE-dependent fashion. Model results reflect an efficient uptake mechanism, consistent with the low molecular weight of the radiopharmaceutical and the relatively high density of available binding sites. These data help better define the imaging utilities of (99m)Tc-Duramycin as a novel PE-binding agent. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Room temperature synthesis of high temperature stable lanthanum phosphate–yttria nano composite

    Energy Technology Data Exchange (ETDEWEB)

    Sankar, Sasidharan; Raj, Athira N.; Jyothi, C.K. [Material Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Thiruvananthapuram 695019 (India); Warrier, K.G.K., E-mail: wwarrierkgk@yahoo.co.in [Material Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Thiruvananthapuram 695019 (India); Padmanabhan, P.V.A. [Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2012-07-15

    Graphical abstract: A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Highlights: ► A novel lanthanum phosphate–Y{sub 2}O{sub 3} nano composite is synthesized for the first time using a modified facile sol gel process. ► The composite becomes crystalline at 600 °C and X-ray diffraction pattern is indexed for monoclinic LaPO{sub 4} and cubic yttria. ► The composite synthesized was tested up to 1300 °C and no reaction between the phases of the constituents is observed with the morphologies of the phases being retained. -- Abstract: A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Lanthanum phosphate (80 wt%)–yttria (20 wt%) nano composite (LaPO{sub 4}–20%Y{sub 2}O{sub 3}), has an average particle size of ∼70 nm after heat treatment of precursor at 600 °C. TG–DTA analysis reveals that stable phase of the composite is formed on heating the precursor at 600 °C. The TEM images of the composite show rod shape morphology of LaPO{sub 4} in which yttria is acquiring near spherical shape. Phase identification of the composite as well as the phase stability up to 1300 °C was carried out using X-ray diffraction technique. With the phases being stable at higher temperatures, the composite synthesized should be a potential material for high temperature applications like thermal barrier coatings and metal melting applications.

  6. Modeling and characterization of dielectrophoretically structured piezoelectric composites using piezoceramic particle inclusions with high aspect ratios

    NARCIS (Netherlands)

    Ende, D.A. van den; Maier, R.A.; Neer, P.L.M.J. van; Zwaag, S. van der; Randall, C.A.; Groen, W.A.

    2013-01-01

    In this work, the piezoelectric properties at high electric fields of dielectrophoretically aligned PZT - polymer composites containing high aspect ratio particles (such as short fibers) are presented. Polarization and strain as a function of electric field are evaluated. The properties of the

  7. Metal-induced shifts in benthic macroinvertebrate community composition in Andean high altitude streams

    NARCIS (Netherlands)

    Loayza-Muro, R.A.; Elías-Letts, R.; Marticorena-Ruíz, J.K.; Palomino, E.J.; Duivenvoorden, J.F.; Kraak, M.H.S.; Admiraal, W.

    2010-01-01

    High altitude creates unique challenging conditions to biota that limit the diversity of benthic communities. Because environmental pollution may add further stress to life at high altitude, the present study explored the effect of metal pollution on the macroinvertebrate community composition in

  8. Advanced processing of lead titanate-polyimide composites for high temperature piezoelectric sensing

    NARCIS (Netherlands)

    Khanbareh, H.; Hegde, M.; Zwaag, S. van der; Groen, W.A.

    2015-01-01

    High performance polymer-ceramic composites are presented as promising candidates for high temperature piezoelectric sensing applications. lead-titanate (PT) ceramic particulate is incorporated into a polyetherimide polymer matrix, (PEI) at a specific volume fraction of 20% in the forms of 0-3 and

  9. A model for the bioaccumulation of {sup 99}Tc in lobsters (Homarus gammarus) from the West Cumbrian coast

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Y.S.; Vives i Batlle, J. E-mail: jordi.vives@westlakes.ac.uk

    2003-07-01

    A biokinetic model is presented that simulates the uptake and release of {sup 99}Tc by the European lobster (Homarus gammarus). This organism is of significant radioecological interest since lobsters, in contrast to most other organisms, have a high affinity for {sup 99}Tc. The model is designed to represent annually averaged {sup 99}Tc concentrations in lobsters from the Cumbrian coast, where significant levels of {sup 99}Tc have been released under authorisation by the nuclear fuel reprocessing plant at BNFL Sellafield. This paper describes the construction of the model, how it was calibrated using data from published literature, and preliminary results indicating that model output agrees well with the available monitoring data. Given that this model successfully combines laboratory and field data, this research could potentially make a significant contribution to the field, as, to date, it has been difficult to predict and explain concentrations of {sup 99}Tc in lobsters.

  10. Preparation, quality control and biological evaluation of {sup 99m}Tc-labelled cationic steroid antibiotic (CSA-13)

    Energy Technology Data Exchange (ETDEWEB)

    Roohi, S.; Amir, N.; Mushtaq, A.; Salahuddin, S.M.; Jehangir, M. [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Isotope Production Div.; Savage, P.B. [Brigham Young Univ., Provo, UT (United States). Dept. of Chemistry and Biochemistry

    2009-07-01

    Ceragenins (CSAs) are a new class of antimicrobial agents that display broad spectrum antibacterial activity and may find use in the treatment of various infections. A member of this class CSA-13 was labelled with {sup 99m}Tc using SnCl{sub 2}.H{sub 2}O as a reducing agent. The labelling efficiency depended on the ligand/reductant ratio, pH and volume of the reaction mixture. The radiochemical purity and stability of {sup 99m}Tc-CSA was determined by thin layer chromatography. Biodistribution studies of {sup 99m}Tc-CSA were performed in Sprague Dawley rats. Liver and spleen uptake was quite high. A significantly higher accumulation of {sup 99m}Tc-CSA was seen at sites of S. aureus infected rats. The results were compared with {sup 99m}Tc-Ciprofloxacin. (orig.)

  11. Pharmacokinetic characteristics of 99mTc-Ethylene-l-dicysteine (99mTc-EC).

    Science.gov (United States)

    Surma, M J; Wiewiórka, J; Szadkowska, A; Liniecki, J

    1999-01-01

    Ethylenedicysteine-99mTc (99mTc-EC) has been more and more commonly applied in dynamic studies as well as for clearance determinations. However, it was necessary to investigate in detail the pharmacokinetic characteristics of the radiopharmaceutical which may be important for its applicability in assessment of renal function. Kidney images obtained from renoscintigraphy are characterised by excellent quality without visualisation of the organs adjacent to kidneys (liver, spleen). Renoscintigraphic curves demonstrate typical shapes with TMAX and T1/2 values not differing from the corresponding values obtained for other radiopharmaceuticals (99mTc-MAG3, 131I-OIH). In plasma, 99mTc-EC binds with proteins to a considerably lesser degree (c. 1/3) than 131I-OIH (c. 2/3), or 99mTc-MAG3 (> 9/10). No binding of 99mTc-EC with erythrocytes has been demonstrated, whereas 131I-OIH attaches to or penetrates the red blood cells (10-12%). 99mTc-EC is quickly excreted from the organism: 40 min after i.v. injection up to 70% of the administered radiopharmaceutical is found in urine, and at 1 and 1.5 h after the administration 80% and 95%, respectively. The distribution of 99mTc-EC in the organism can be described in a fully satisfactory way by means of an open two-compartment model, which allows this model to be used for clearance determinations. Comparison of the values of renal plasma clearance without collection of urine with the values determined by means of measurement of activity excreted with urine and mean blood concentration over a finite time interval leads to the conclusion that extrarenal plasma clearance of this compound (via the liver?) is negligible and amounts to c. 17 ml/min (5-6% of the total). The obtained correlation between clearance values for 99mTc-EC and 131I-OIH supports the contention that extrarenal excretion rate of 99mTc-EC (through the liver and bile ducts) is lower than the corresponding rates of either 131I-OIH or 99mTc-MAG3. A very close correlation

  12. Hemocompatible polyethersulfone/polyurethane composite membrane for high-performance antifouling and antithrombotic dialyzer.

    Science.gov (United States)

    Yin, Zehua; Cheng, Chong; Qin, Hui; Nie, Chuanxiong; He, Chao; Zhao, Changsheng

    2015-01-01

    Researches on blood purification membranes are fuelled by diverse clinical needs, such as hemodialysis, hemodiafiltration, hemofiltration, plasmapheresis, and plasma collection. To approach high-performance dialyzer, the integrated antifouling and antithrombotic properties are highly necessary for the design/modification of advanced artificial membranes. In this study, we propose and demonstrate that the physical blend of triblock polyurethane (PU) and polyethersulfone (PES) may advance the performance of hemodialysis membranes with greatly enhanced blood compatibility. It was found that the triblock PU could be blended with PES at high ratio owing to their excellent miscibility. The surfaces of the PES/PU composite membranes were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurement, and surface ζ-potentials. The results indicated that the membrane surfaces were assembled with hydrophilic segregation layer owing to the migration of amphiphilic PU segments during membrane preparation, which might confer the composite membranes with superior hemocompatibility. The cross-section scanning electron microscopy images of the composite membranes exhibited structure transformation from finger-like structure to sponge-like structure, which indicated that the composite membrane had tunable porosity and permeability. The further ultrafiltration experiments indicated that the composite membranes showed increased permeability and excellent antifouling ability. The blood compatibility observation indicated that PES/PU composite membranes owned decreased protein adsorption, suppressed platelet adhesion, and prolonged plasma recalcification time. These results indicated that the PES/PU composite membranes exhibited enhanced antifouling and antithrombotic properties than the pristine PES membrane. The strategy may forward the fabrication of blood compatible composite membranes for

  13. High Speed Thermal Imaging on Ballistic Impact of Triaxially Braided Composites

    Science.gov (United States)

    Johnston, Joel P.; Pereira, J. Michael; Ruggeri, Charles R.; Roberts, Gary D.

    2017-01-01

    Ballistic impact experiments were performed on triaxially braided polymer matrix composites to study the heat generated in the material due to projectile velocity and penetration damage. Quantifying the heat generation phenomenon is crucial for attaining a better understanding of composite behavior and failure under impact loading. The knowledge gained can also be used to improve physics-based models which can numerically simulate impact of composites. Triaxially braided (0/+60/-60) composite panels were manufactured with T700S standard modulus carbon fiber and two epoxy resins. The PR520 (toughened) and 3502 (untoughened) resin systems were used to make different panels to study the effects of resin properties on temperature rise. Ballistic impact tests were conducted on these composite panels using a gas gun, and different projectile velocities were applied to study the effect on the temperature results. Temperature contours were obtained from the rear surface of the panel during the test through a high speed, infrared (IR) thermal imaging system. The contours show that high temperatures were locally generated and more pronounced along the axial tows for the T700S/PR520 composite specimens; whereas, tests performed on T700S/3502 composite panels using similar impact velocities demonstrated a widespread area of lower temperature rises. Nondestructive, ultrasonic C-scan analyses were performed to observe and verify the failure patterns in the impacted panels. Overall, the impact experimentation showed temperatures exceeding 525 K (485degF) in both composites which is well above the respective glass transition temperatures for the polymer constituents. This expresses the need for further high strain rate testing and measurement of the temperature and deformation fields to fully understand the complex behavior and failure of the material in order to improve the confidence in designing aerospace components with these materials.

  14. {sup 99m}Tc-interleukin-2 and {sup 99m}Tc-HMPAO granulocyte scintigraphy in patients with inactive Crohn's disease

    Energy Technology Data Exchange (ETDEWEB)

    Annovazzi, Alessio; Chianelli, Marco; Capriotti, Gabriela; Signore, Alberto [Nuclear Medicine Unit, Department of Clinical Sciences, Policlinico Umberto I, University ' ' La Sapienza' ' , 00161, Rome (Italy); Biancone, Livia; Pallone, Francesco [Gastroenterology Unit, University ' ' Tor Vergata' ' , Rome (Italy); Caviglia, Renato [Gastroenterology Unit, University ' ' Campus Biomedico' ' , Rome (Italy); Mather, Stephen J. [Department of Nuclear Medicine, St Bartholomew' s Hospital, Cancer Research UK, London (United Kingdom); Caprilli, Renzo [Gastroenterology Unit, Department of Clinical Sciences, University ' ' La Sapienza' ' , Rome (Italy); Scopinaro, Francesco [Department of Radiological Sciences, University ' ' La Sapienza' ' , Rome (Italy)

    2003-03-01

    Crohn's disease (CD) is a chronic inflammatory bowel disease that may involve the whole gut. Marked intestinal T cell and macrophage activation is a key feature of the disease. Polymorphonuclear cell infiltration is also observed in the diseased gut, mainly during active inflammation. Scintigraphic detection of granulocytes and activated lymphocytes infiltrating the gut wall may be useful in identifying a subgroup of patients with clinically inactive CD who are undergoing early clinical relapse. The aims of the present study were (a) to compare the effectiveness of scintigraphy with {sup 99m}Tc-labelled interleukin-2 ({sup 99m}Tc-IL2) and with {sup 99m}Tc-HMPAO labelled granulocytes ({sup 99m}Tc-WBC) in detecting the presence and extent of bowel inflammation in patients with long-term inactive CD (>12 months) and (b) to assess the accuracy of these techniques in predicting future disease relapse. We studied 29 patients with ileal and/or colonic CD in stable clinical remission (Crohn's Disease Activity Index <150 for at least 12 months) using both {sup 99m}Tc-IL2 and {sup 99m}Tc-WBC scintigraphy in order to evaluate the extent of acute and chronic inflammation in the bowel. Planar and single-photon emission tomography images were acquired in each patient at 1 h p.i. For quantitative analysis of {sup 99m}Tc-IL2 uptake, the abdomen was divided into 32 regions of interest. Despite the absence of symptoms, 18 patients (62%) showed a positive {sup 99m}Tc-IL2 and 18 (62%) a positive {sup 99m}Tc-WBC scan. Only 12 patients (41.4% of the total group) were positive on both scans, and the sites of IL2 and granulocyte bowel uptake were usually located in different segments, indicating that in CD, acute and chronic inflammation can be present in different sites. As far as the prognostic role of the two scans in predicting future disease relapse is concerned, both {sup 99m}Tc-IL2 and {sup 99m}Tc-WBC scintigraphy showed a high negative predictive value (1.00 and 0

  15. High efficiency solid state dye sensitized solar cells with graphene-polyethylene oxide composite electrolytes.

    Science.gov (United States)

    Akhtar, M Shaheer; Kwon, Soonji; Stadler, Florian J; Yang, O Bong

    2013-06-21

    Novel and highly effective composite electrolytes were prepared by combining the two dimensional graphene (Gra) and polyethylene oxide (PEO) for the solid electrolyte of dye sensitized solar cells (DSSCs). Gra sheets were uniformly coated by the polymer layer through the ester carboxylate bonding between oxygenated species on Gra sheets and PEO. The Gra-PEO composite electrolyte showed the large scale generation of iodide ions in a redox couple. From rheological analysis, the decrease in viscosity after the addition of LiI and I2 in the Gra-PEO electrolyte might be explained by the dipolar interactions being severely disrupted by the ionic interactions of Li(+), I(-), and I3(-) ions. A composite electrolyte with 0.5 wt% Gra presented a higher ionic conductivity (3.32 mS cm(-1)) than those of PEO and other composite electrolytes at room temperature. A high overall conversion efficiency (∼5.23%) with a very high short circuit current (JSC) of 18.32 mA cm(-2), open circuit voltage (VOC) of 0.592 V and fill factor (FF) of 0.48 was achieved in DSSCs fabricated with the 0.5 wt% Gra-PEO composite electrolyte. This enhanced photovoltaic performance might be attributed to the large scale formation of iodide ions in the redox electrolyte and the relatively high ionic conductivity.

  16. Uniform mixing of antiferromagnetism and high- Tc superconductivity in multilayer copper oxides Ba2Can-1CunO2nF2 (n=2,3,4) with apical fluorines: C63u-NMR/NQR and F19-NMR studies

    Science.gov (United States)

    Shimizu, S.; Sakaguchi, T.; Mukuda, H.; Kitaoka, Y.; Shirage, P. M.; Kodama, Y.; Iyo, A.

    2009-02-01

    We report C63u-NMR/NQR and F19-NMR studies on the multilayered high- Tc copper oxides Ba2Can-1CunO2nF2 with n=2,3,4 , where n is the number of CuO2 planes. It is revealed that bilayered Ba2CaCu2O4F2 is an underdoped superconductor with hole carriers, which are introduced into CuO2 planes by an unexpected deviation from the nominal content of apical fluorines. In a previous paper, we proposed a self-doping mechanism as the origin of carrier doping in n=3 and n=4 ; in the mechanism, electrons are transferred from the inner CuO2 plane (IP) to the outer one (OP). However, since it has been found that the bilayered compound is hole doped, we have re-examined the superconducting and magnetic properties in n=3 and n=4 by C63u-NMR/NQR and F19-NMR . The extensive NMR studies have confirmed that the apical-fluorine compounds are not self-doped but hole doped and that antiferromagnetism (AFM) and superconductivity (SC) coexist in a single CuO2 plane. In n=4 , the AFM ordering occurs at TN=80K well above Tc=55K , where the respective AFM moments are MAFM=0.11μB and 0.18μB at the OP and the IP. In n=3 , on the other hand, the underdoped single IP exhibits a spontaneous moment MAFM=0.12μB at low temperatures and a peak in the nuclear-spin-lattice relaxation rate 1/T1 of F19 at TN=23K much lower than Tc=76K . We note that the increase in the number of IPs from one to two results in the strengthening of the interlayer coupling; TN increases as the interlayer coupling becomes stronger, although the doping levels for both compounds are comparable. Consequently, we conclude that the uniform mixing of AFM and SC is a general property inherent to a single CuO2 plane in an underdoped regime for hole doping. This conclusion incorporates the angle-resolved photoemission spectroscopy results on the n=4 compound [Chen , Phys. Rev. Lett. 97, 236401 (2006)]; it was found that the two Fermi sheets of the IP and OP are observed and that the SC gap opens at the IP and OP below Tc=55K .

  17. High Temperature Joining and Characterization of Joint Properties in Silicon Carbide-Based Composite Materials

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay

    2015-01-01

    Advanced silicon carbide-based ceramics and composites are being developed for a wide variety of high temperature extreme environment applications. Robust high temperature joining and integration technologies are enabling for the fabrication and manufacturing of large and complex shaped components. The development of a new joining approach called SET (Single-step Elevated Temperature) joining will be described along with the overview of previously developed joining approaches including high temperature brazing, ARCJoinT (Affordable, Robust Ceramic Joining Technology), diffusion bonding, and REABOND (Refractory Eutectic Assisted Bonding). Unlike other approaches, SET joining does not have any lower temperature phases and will therefore have a use temperature above 1315C. Optimization of the composition for full conversion to silicon carbide will be discussed. The goal is to find a composition with no remaining carbon or free silicon. Green tape interlayers were developed for joining. Microstructural analysis and preliminary mechanical tests of the joints will be presented.

  18. Additive Manufacturing of Reactive In Situ Zr Based Ultra-High Temperature Ceramic Composites

    Science.gov (United States)

    Sahasrabudhe, Himanshu; Bandyopadhyay, Amit

    2016-03-01

    Reactive in situ multi-material additive manufacturing of ZrB2-based ultra-high-temperature ceramics in a Zr metal matrix was demonstrated using LENS™. Sound metallurgical bonding was achieved between the Zr metal and Zr-BN composites with Ti6Al4V substrate. Though the feedstock Zr power had α phase, LENS™ processing of the Zr powder and Zr-BN premix powder mixture led to the formation of some β phase of Zr. Microstructure of the Zr-BN composite showed primary grains of zirconium diboride phase in zirconium metal matrix. The presence of ZrB2 ceramic phase was confirmed by X-ray diffraction (XRD) analysis. Hardness of pure Zr was measured as 280 ± 12 HV and, by increasing the BN content in the feedstock, the hardness was found to increase. In Zr-5%BN composite, the hardness was 421 ± 10 HV and the same for Zr-10%BN composite was 562 ± 10 HV. It is envisioned that such multi-materials additive manufacturing will enable products in the future that cannot be manufactured using traditional approaches particularly in the areas of high-temperature metal-ceramic composites with compositional and functional gradation.

  19. Construction of 3D Skeleton for Polymer Composites Achieving a High Thermal Conductivity.

    Science.gov (United States)

    Yao, Yimin; Sun, Jiajia; Zeng, Xiaoliang; Sun, Rong; Xu, Jian-Bin; Wong, Ching-Ping

    2018-02-02

    Owing to the growing heat removal issue in modern electronic devices, electrically insulating polymer composites with high thermal conductivity have drawn much attention during the past decade. However, the conventional method to improve through-plane thermal conductivity of these polymer composites usually yields an undesired value (below 3.0 Wm -1 K -1 ). Here, construction of a 3D phonon skeleton is reported composed of stacked boron nitride (BN) platelets reinforced with reduced graphene oxide (rGO) for epoxy composites by the combination of ice-templated and infiltrating methods. At a low filler loading of 13.16 vol%, the resulting 3D BN-rGO/epoxy composites exhibit an ultrahigh through-plane thermal conductivity of 5.05 Wm -1 K -1 as the best thermal-conduction performance reported so far for BN sheet-based composites. Theoretical models qualitatively demonstrate that this enhancement results from the formation of phonon-matching 3D BN-rGO networks, leading to high rates of phonon transport. The strong potential application for thermal management has been demonstrated by the surface temperature variations of the composites with time during heating and cooling. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Fabrication of Aligned-Carbon-Nanotube-Composite Paper with High and Anisotropic Conductivity

    Directory of Open Access Journals (Sweden)

    Yuki Fujitsuka

    2012-01-01

    Full Text Available A functional carbon-nanotube (CNT-composite paper is described in which the CNTs are aligned. This “aligned-CNT composite paper” is a flexible composite material that has CNT functionality (e.g., electrical conductivity despite being a paper. An advanced fabrication method was developed to overcome the problem of previous CNT-composite papers, that is, reduced conductivity due to random CNT alignment. Aligning the CNTs by using an alternating current (AC field was hypothesized to increase the electrical conductivity and give the paper an anisotropic characteristic. Experimental results showed that a nonionic surfactant was not suitable as a CNT dispersant for fabricating aligned-CNT composite paper and that catechin with its six-membered rings and hydrophilic groups was suitable. Observation by scanning electron microscopy of samples prepared using catechin showed that the CNTs were aligned in the direction of the AC field on the paper fibers. Measurement of the electric conductivity showed that the surface resistance was different between the direction of the aligned CNTs (high conductivity and that of verticality (low. The conductivity of the aligned-CNT-composite paper samples was higher than that of nonaligned samples. This unique and functional paper, which has high and anisotropic conductivity, is applicable to a conductive material to control the direction of current.

  1. Concentration of {sup 99m}Tc-pertechnetate and {sup 188}Re-perrhenate

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, M.S.; Mushtaq, A.; Jehangir, M. [Isotope Production Div., Pakistan Inst. of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)

    2006-07-01

    The radioactive concentrations of {sup 99m}Tc/{sup 188}Re from their generators are dependent upon the specific activity of {sup 99}Mo/{sup 188}W, which dictates the bed size of the alumina/gel column and the volume of physiological saline needed as eluent. Because of the high content of inactive molybdenum/tungsten in neutron irradiated MoO{sub 3}/WO{sub 3}, large columns containing alumina/gel are needed to produce chromatographic {sup 99}Mo {yields} {sup 99m}Tc/{sup 188}W {yields} {sup 188}Re generators. This results in large elution volumes containing relatively high {sup 99}Mo/{sup 188}W contents and low concentrations of {sup 99m}Tc/{sup 188}Re. The decrease in radioactive concentration, or specific volume, places a limitation on some of the clinical procedures. We report post elution concentration of {sup 99m}Tc/{sup 188}Re using in house prepared silver cation exchange and alumina column. The high bolus volumes (10-60 ml saline) can conveniently be concentrated in 1 ml of saline. This approach also works very effectively to yield high specific volume solutions of {sup 99m}Tc-pertechnetate from a fission {sup 99}Mo loaded alumina generator towards the end of its normal working life. (orig.)

  2. Mismatched uptake of Tc-99m-ECD and Tc-99m-HMPAO in subacute cerebral infarction: Tc-99m-ECD for viability and Tc-99m-HMPAO for flow restoration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D. S.; Hyun, I. Y.; Kim, S. K. [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)] [and others

    1997-07-01

    Tc-99m-HMPAO reflects tissue perfusion but Tc-99m-ECD uptake is affected by tissue viability in addition to tissue perfusion which the varied state of cellular retention of Tc-99m-ECD reflects. Luxuriously perfused area on Tc-99m-HMPAO SPECT implies that this cortex was already reperfused either spontaneously or after thrombolysis and that accompanied paralysis of vascular reactivity in those zones warms progressive deterioration. We tried to find out if we can use sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT to reveal cortical perfusion and severity and range of risky areas of cerbral cortex despite reperfusion in sub-acute infarction. In 13 patients (M ; F =7 : 6, mean age 57 (range: 26-84)) with cortical (n=12) and basal ganglia infarction (1), we performed sequential Tc-99m-ECD/Tc-99m-HMPAO SPECT at the same position. At first, 555 MBq of Tc-99m-ECD was injected and imaged and then 1110 MBq of Tc-99m-HMPAO was injected again and imaged with the patients in situ, and the first image (Tc-99m-ECD) and the subtracted image (2nd- 1st : Tc-99m-HMPAO) were compared slice by slice. Study was done from 3 days to 31 days (16{+-}9) after ictus. Tc-99m-ECD uptake was always less than or equal to Tc-99m-HMPAO uptake at the lesion in all cases. Luxury perfusion was prominent in four patients. Mismatched uptake was found in 10 patients. Severity of mismatch showed diverse spectrum and was ranged from total middle cerebral artery territory (1 case) to peripheral thin zones around infarction (2 cases). The other 7 showed intermediate amount of tissues with mismatch , i.e., Tc-99m-ECD defects where Tc-99m-HMPAO uptake is in part increased, normal or decreased. Upon discharge, patients having more uptake with Tc-99m-ECD predicted improvement. Patients having mismatched uptake went dichotomous way. In conclusion, Tc-99m-ECD/Tc-99m-HMPAO sequential SPECT is feasible and reveal both tissue perfusion (Tc-99m-HMPAO ) and discrepant Tc-99m-ECD uptake probably reflecting viability in acute

  3. Supplementary Material for: High-Order Composite Likelihood Inference for Max-Stable Distributions and Processes

    KAUST Repository

    Castruccio, Stefano

    2016-01-01

    In multivariate or spatial extremes, inference for max-stable processes observed at a large collection of points is a very challenging problem and current approaches typically rely on less expensive composite likelihoods constructed from small subsets of data. In this work, we explore the limits of modern state-of-the-art computational facilities to perform full likelihood inference and to efficiently evaluate high-order composite likelihoods. With extensive simulations, we assess the loss of information of composite likelihood estimators with respect to a full likelihood approach for some widely used multivariate or spatial extreme models, we discuss how to choose composite likelihood truncation to improve the efficiency, and we also provide recommendations for practitioners. This article has supplementary material online.

  4. High-order Composite Likelihood Inference for Max-Stable Distributions and Processes

    KAUST Repository

    Castruccio, Stefano

    2015-09-29

    In multivariate or spatial extremes, inference for max-stable processes observed at a large collection of locations is a very challenging problem in computational statistics, and current approaches typically rely on less expensive composite likelihoods constructed from small subsets of data. In this work, we explore the limits of modern state-of-the-art computational facilities to perform full likelihood inference and to efficiently evaluate high-order composite likelihoods. With extensive simulations, we assess the loss of information of composite likelihood estimators with respect to a full likelihood approach for some widely-used multivariate or spatial extreme models, we discuss how to choose composite likelihood truncation to improve the efficiency, and we also provide recommendations for practitioners. This article has supplementary material online.

  5. High-Dielectric-Constant Silver-Epoxy Composites as Embedded Dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Lai; Lee, Burtrand I.; Chen, Sihai; Samuels, William D.; Exarhos, Gregory J.

    2005-07-08

    We report the synthesis of an epoxy-based composite containing randomly distributed silver nanoparticles with a narrow size distribution centered around 40nm. The surface of the Ag nanoparticles is coated with a thin layer of mercaptosuccinic acid (MSA) in order to promote formation of the Ag-epoxy while retaining flexibility of the polymer matrix. This composite is the basis of a prototype capacitor formed by spin coating the synthesized Ag-epoxy (40nm Ag) mixture onto a gold-deposited aluminum substrate. A series of Ag-epoxy composites with various Ag volume fractions was investigated in order to determine the composition associated with optimum capacitor performance. The high dielectric constant (> 300) and relatively low dielectric loss (<0.05) render this material of promising potential for embedded capacitor applications.

  6. Thermal properties of silica-filled high density polyethylene composites compatibilized with glut palmitate

    Science.gov (United States)

    Samsudin, Dalina; Ismail, Hanafi; Othman, Nadras; Hamid, Zuratul Ain Abdul

    2017-07-01

    A study of thermal properties resulting from the utilization of Glut Palmitate (GP) on the silica filled high density polyethylene (HDPE) composites was carried out. The composites with the incorporation of GP at 0.5, 1.0, 2.0 and 3.0 phr were prepared by using an internal mixer at the temperature 180 °C and the rotor speed of 50 rpm. The thermal behaviours of the composites were then investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the crystallinity and the thermal stability of the composites increased with the incorporation of GP. The highest crystallinity contents and decomposition temperatures were observed at the 1 phr GP loading.

  7. Modeling of high composition AlGaN channel high electron mobility transistors with large threshold voltage

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, Sanyam, E-mail: bajaj.10@osu.edu; Hung, Ting-Hsiang; Akyol, Fatih; Nath, Digbijoy; Rajan, Siddharth [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2014-12-29

    We report on the potential of high electron mobility transistors (HEMTs) consisting of high composition AlGaN channel and barrier layers for power switching applications. Detailed two-dimensional (2D) simulations show that threshold voltages in excess of 3 V can be achieved through the use of AlGaN channel layers. We also calculate the 2D electron gas mobility in AlGaN channel HEMTs and evaluate their power figures of merit as a function of device operating temperature and Al mole fraction in the channel. Our models show that power switching transistors with AlGaN channels would have comparable on-resistance to GaN-channel based transistors for the same operation voltage. The modeling in this paper shows the potential of high composition AlGaN as a channel material for future high threshold enhancement mode transistors.

  8. Hypervelocity Impact Experiments on Epoxy/Ultra-High Molecular Weight Polyethylene Composite Panels Reinforced with Nanotubes

    Science.gov (United States)

    Khatiwada, Suman; Laughman, Jay W.; Armada, Carlos A.; Christiansen, Eric L.; Barrera, Enrique V.

    2012-01-01

    Advanced composites with multi-functional capabilities are of great interest to the designers of aerospace structures. Polymer matrix composites (PMCs) reinforced with high strength fibers provide a lightweight and high strength alternative to metals and metal alloys conventionally used in aerospace architectures. Novel reinforcements such as nanofillers offer potential to improve the mechanical properties and add multi-functionality such as radiation resistance and sensing capabilities to the PMCs. This paper reports the hypervelocity impact (HVI) test results on ultra-high molecular weight polyethylene (UHMWPE) fiber composites reinforced with single-walled carbon nanotubes (SWCNT) and boron nitride nanotubes (BNNT). Woven UHMWPE fabrics, in addition to providing excellent impact properties and high strength, also offer radiation resistance due to inherent high hydrogen content. SWCNT have exceptional mechanical and electrical properties. BNNT (figure 1) have high neutron cross section and good mechanical properties that add multi-functionality to this system. In this project, epoxy based UHMWPE composites containing SWCNT and BNNT are assessed for their use as bumper shields and as intermediate plates in a Whipple Shield for HVI resistance. Three composite systems are prepared to compare against one another: (I) Epoxy/UHMWPE, (II) Epoxy/UHMWPE/SWCNT and (III) Epoxy/UHMWPE/SWCNT/BNNT. Each composite is a 10.0 by 10.0 by 0.11 cm3 panel, consisting of 4 layers of fabrics arranged in cross-ply orientation. Both SWCNT and BNNT are 0.5 weight % of the fabric preform. Hypervelocity impact tests are performed using a two-stage light gas gun at Rice University

  9. PREFACE: 2013 Joint IMEKO (International Measurement Confederation) TC1-TC7-TC13 Symposium: Measurement Across Physical and Behavioural Sciences

    Science.gov (United States)

    Battista Rossi, Giovanni; Crenna, Francesco; Belotti, Vittorio

    2013-09-01

    The 2013 Joint IMEKO (International Measurement Confederation) TC1-C7-TC13 was organised by the University of Genova - DIME/MEC, Measurement Laboratory, Italy, on 4-6 September 2013. The work of this symposium is reported in this volume. The scope of the symposium includes the main topics covered by the above Technical Committees: TC1 Education and Training in Measurement and Instrumentation TC7 Measurement Science TC13 Measurements in Biology and Medicine This is in keeping with the tradition set by the previous events of this well established series. There has been a special focus on measurement across physical and behavioural sciences, with the aim of highlighting the interdisciplinary character of measurement science and of promoting constructive interactions with scientists in other disciplines. The discussion was introduced by keynote lectures on measurement challenges in psychophysics, psychometrics and quantum physics. The symposium was attended by experts working in these areas from 18 countries, including USA, Australia and Japan, and provided a useful forum for them to share and exchange their work and ideas. In total over sixty papers are included in the volume, organised according to the presentation sessions. Each paper was independently peer-reviewed by two reviewers from a distinguished international panel. The Symposium was held in Genova, which was the European Capital of Culture in 2004, and took place in Palazzo Ducale, an important historical building whose construction started in the 13th century, and that has been the house of the Duke of Genova from the 14th century. Genova, whose name comes from the Latin word 'Janua' (meaning 'door', as January is the door month of the year), has been regarded over the centuries as a door connecting Europe with the different countries and cultures of the Mediterranean basin and thus was an appropriate site for an international symposium involving different and new scientific visions and approaches to

  10. Effect of different light-curing devices and aging procedures on composite knoop microhardness

    Directory of Open Access Journals (Sweden)

    Fernanda Regina Voltarelli

    2009-12-01

    Full Text Available The aim of this study was to evaluate the effect of light-curing devices (Halogen/HAL, Light Emitting Diodes/LED, Argon Laser/LAS and Plasma Arc/PAC and aging procedures (Mechanical Cycling/MC, Thermal Cycling/TC, Storage/S, MC+TC and MC+TC+S on the micro-hardness of bottom/B and top/T surfaces of 2-mm-high composite resin cylinders. The Knoop microhardness test (25 g, 20 s on both B and T was performed before and after each aging procedure. For B and T, before aging procedures, PAC showed reduced polymerization effectiveness when compared with HAL. In the T, after TC, PAC and LAS had also showed reduced polymerization effectiveness when compared to HAL and LED. For all light-curing devices, MC+TC+S and S affected the Knoop microhardness values. In the B, no difference could be observed among the aging procedures for PAC. From all light-curing units, PAC may have rendered composites of reduced quality and the storage aging procedures were the most harmful to the polymer hardness.

  11. Synthesis of trevorite to capture Tc

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Colin

    2011-09-02

    Spinel containing technetium can be used to prevent Tc volatilization during vitrification of radioactive waste. Spinel dissolves in glass at elevated temperatures. This study focuses on the synthesis of spinel and the retention of rhenium, a nonradioactive surrogate for Tc in the crystals. To produce trevorite, a nickel-iron spinel (NiFe2O4), Fe and Ni nitrates were mixed with alkali nitrates along with Al(OH)3 and heated to 500 to 800°C. The trevorite content in samples (up to 40 mass%) was measured with x-ray diffraction. Viable samples were rerun with KReO4. Scanning electron microscopy-energy dispersive spectroscopy detected that Re became partly immobilized in spinel-forming crystals.

  12. Detection of sites of infection in mice using {sup 99m}Tc-labeled PN{sub 2}S-PEG conjugated to UBI and {sup 99m}Tc-UBI: a comparative biodistribution study

    Energy Technology Data Exchange (ETDEWEB)

    Melendez-Alafort, Laura [Department of Pharmaceutical Sciences, University of Padua, 35131 Padova (Italy)], E-mail: lmalafort@yahoo.com; Nadali, Anna; Pasut, Gianfranco; Zangoni, Elena [Department of Pharmaceutical Sciences, University of Padua, 35131 Padova (Italy); De Caro, Raffaele [Department of Anatomy and Physiology, University of Padua, 35131 Padova (Italy); Cariolato, Luca [Department of Pharmaceutical Sciences, University of Padua, 35131 Padova (Italy); Giron, Maria Cecilia [Department of Pharmacology and Anesthesiology, University of Padua, 35131 Padova (Italy); Castagliuolo, Ignazio [Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, 35131 Padova (Italy); Veronese, Francesco M.; Mazzi, Ulderico [Department of Pharmaceutical Sciences, University of Padua, 35131 Padova (Italy)

    2009-01-15

    The antimicrobial peptide ubiquicidin (UBI) directly labeled with technetium-99m ({sup 99m}Tc) has recently been shown to be specifically taken up at sites of infection; however, its chemical structure is not well defined. To address this problem, the aim of the present study was to label UBI using poly(ethyleneglycol)-N-(N-(3-diphenylphosphinopropionyl)glycyl) -S-tritylcysteine ligand (PEG-PN{sub 2}S) in order to compare its ability to detect infection sites with that of {sup 99m}Tc-UBI. Methods: The PN{sub 2}S-PEG-UBI conjugate was prepared and labeled with {sup 99m}Tc, and its radiochemical purity was subsequently assessed. The stability of the conjugate to cysteine challenge and dilution with both saline solution and phosphate buffer was determined and serum stability and protein binding were also assessed. In vivo studies were carried out in healthy mice to study the biodistribution of {sup 99m}Tc-PN{sub 2}S-PEG-UBI and its precursor {sup 99m}Tc-PN{sub 2}S-PEG and in infected mice to compare the uptakes of {sup 99m}Tc-UBI and {sup 99m}Tc-PN{sub 2}S-PEG-UBI at the site of infection using scintigraphic imaging and ex vivo tissue counting. Results: {sup 99m}Tc-PN{sub 2}S-PEG-UBI was obtained with high radiochemical purity (98{+-}1%) and high stability. The amphiphilic nature of the conjugate leads to a tendency to form micellar aggregates that explain the high protein binding values obtained. Biodistribution studies in mice showed low renal clearance followed by a predominant reticuloendothelial system clearance that limits its application in the abdominal area. Statistical analysis revealed no significant difference between {sup 99m}Tc-UBI and {sup 99m}Tc-PN{sub 2}S-PEG-UBI uptake in infected mouse thigh, and the site of infection was clearly visualized using scintigraphic imaging. Conclusions: {sup 99m}Tc-PN{sub 2}S-PEG-UBI proved to be as effective as {sup 99m}Tc-UBI in detecting sites of infection; however, the well-defined chemical structure of {sup 99m}Tc

  13. High-tip-speed fiber composite compressor blades: Vibration and strength analysis

    Science.gov (United States)

    Chamis, C. C.; Lynch, J. E.

    1974-01-01

    An analytical procedure is described which couples composite mechanics computer codes with NASTRAN. This procedure was used to perform a detailed analysis of a high-tip-speed fiber composite compressor fan blade. The results indicate that the various vibration modes of this blade are highly coupled. Mechanical load ply stresses are well below the corresponding room temperature strengths. Lamination residual stresses are likely to cause transply cracks and interply delamination. Transply cracks and relaxation of root fixity decrease the vibrational frequencies whereas centrifugal stiffening increases them. Comparisons of results for various parameters are presented in tabular and graphical form.

  14. Evaluation of CVI SiC/SiC Composites for High Temperature Applications

    Science.gov (United States)

    Kiser, D.; Almansour, A.; Smith, C.; Gorican, D.; Phillips, R.; Bhatt, R.; McCue, T.

    2017-01-01

    Silicon carbide fiber reinforced silicon carbide (SiC/SiC) composites are candidate materials for various high temperature turbine engine applications because of their high specific strength and good creep resistance at temperatures of 1400 C (2552 F) and higher. Chemical vapor infiltration (CVI) SiC/SiC ceramic matrix composites (CMC) incorporating Sylramic-iBN SiC fiber were evaluated via fast fracture tensile tests (acoustic emission damage characterization to assess cracking behavior), tensile creep testing, and microscopy. The results of this testing and observed material behavior degradation mechanisms are reviewed.

  15. Plutonium Finishing Plant (PFP) Waste Composition and High Efficiency Particulate Air Filter Loading

    Energy Technology Data Exchange (ETDEWEB)

    ZIMMERMAN, B.D.

    2000-12-11

    This analysis evaluates the effect of the Plutonium Finishing Plant (PFP) waste isotopic composition on Tank Farms Final Safety Analysis Report (FSAR) accidents involving high-efficiency particulate air (HEPA) filter failure in Double-Contained Receiver Tanks (DCRTs). The HEPA Filter Failure--Exposure to High Temperature or Pressure, and Steam Intrusion From Interfacing Systems accidents are considered. The analysis concludes that dose consequences based on the PFP waste isotopic composition are bounded by previous FSAR analyses. This supports USQD TF-00-0768.

  16. A constitutive model for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures

    Directory of Open Access Journals (Sweden)

    Song Wei-Dong

    2013-01-01

    Full Text Available Quasi-static and dynamic tension tests were conducted to study the mechanical properties of particulate-reinforced titanium matrix composites at strain rates ranging from 0.0001/s to 1000/s and at temperatures ranging from 20 °C to 650 °C Based on the experimental results, a constitutive model, which considers the effects of strain rate and temperature on hot deformation behavior, was proposed for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures by using Zener-Hollomon equations including Arrhenius terms. All the material constants used in the model were identified by fitting Zener-Hollomon equations against the experimental results. By comparison of theoretical predictions presented by the model with experimental results, a good agreement was achieved, which indicates that this constitutive model can give an accurate and precise estimate for high temperature flow stress for the studied titanium matrix composites and can be used for numerical simulations of hot deformation behavior of the composites.

  17. Superplastic Deformation of TC6 Alloy

    Directory of Open Access Journals (Sweden)

    DING Ling

    2016-12-01

    Full Text Available The superplastic tensile tests of TC6 alloy were conducted in the temperature range of 800-900℃ by using the maximum m value superplasticity deformation (Max m SPD method and the constant strain rate deformation method at the strain rate range of 0.0001-0.1 s-1. The stress-strain curve of the tensile tests was obtained and the microstructure near the fracture were analyzed by metallographic microscope. The result shows that the superplasticity of TC6 alloy is excellent, and the elongation increases first and then decreases with the increase of strain rate or temperature. When the temperature is 850℃ and strain rate is 0.001 s-1 at constant stain rate tensile tests, the elongation reaches up to 993%. However, the elongation using Max m SPD method at 850℃ is 1353%. It is shown that the material can achieve better superplasticity by using Max m SPD tensile compared to constant stain rate tensile under the same temperature. The superplastic deformation of TC6 alloy can enhance the dynamic recrystallization behavior significantly, the dynamic recrystallization behavior is promoted when strain rate and temperature are increased.

  18. Preparation and preliminary evaluation of {sup 99m}Tc-EC-For-MLFK

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, K.; Verbeke, A.; Vanbilloen, H.; Verbruggen, A. E-mail: alfons.verbruggen@uz.kuleuven.ac.be

    2002-07-01

    For-Met-Leu-Phe-Lys (For-MLFK), a chemotactic peptide that binds with high affinity to granulocytes and monocytes, was labeled with {sup 99m}Tc using ethylene dicysteine (EC) as the metal chelating system. EC was selected because of the rapid renal excretion of its {sup 99m}Tc-complex and therefore, was expected to enhance the degree of urinary elimination of the peptide-conjugate. {sup 99m}Tc-EC-For-MLFK was prepared using a preformed chelate approach. After incubation of {sup 99m}Tc-EC-For-MLFK with total blood, 68.1% of the labeled peptide was associated with WBC and 86% of this cell-associated activity was bound to granulocytes. Biodistribution studies in normal mice revealed a very fast blood clearance (4.1% and 0.6% of I.D. in blood at respectively 5 and 60 min p.i.). However, elimination of the labeled peptide proceeds mainly via the hepatobiliary system (24.5% of I.D. in liver and 48.8% of I.D. in intestines at 60 min p.i.) and to a much lower degree via the kidneys (17.9% in renal system at 60 min p.i.). From these results, it is concluded that {sup 99m}Tc-EC-For-MLFK is not suited to image infections, despite its high binding to granulocytes, since it leads to high, non-specific, abdominal activity.

  19. Nacre-mimetic bulk lamellar composites reinforced with high aspect ratio glass flakes.

    Science.gov (United States)

    Guner, Selen N Gurbuz; Dericioglu, Arcan F

    2016-12-05

    Nacre-mimetic epoxy matrix composites reinforced with readily available micron-sized high aspect ratio C-glass flakes were fabricated by a relatively simple, single-step, scalable, time, cost and man-power effective processing strategy: hot-press assisted slip casting (HASC). HASC enables the fabrication of preferentially oriented two-dimensional inorganic reinforcement-polymer matrix bulk lamellar composites with a micro-scale structure resembling the brick-and-mortar architecture of nacre. By applying the micro-scale design guideline found in nacre and optimizing the relative volume fractions of the reinforcement and the matrix as well as by anchoring the brick-and-mortar architecture, and tailoring the interface between reinforcements and the matrix via silane coupling agents, strong, stiff and tough bio-inspired nacre-mimetic bulk composites were fabricated. As a result of high shear stress transfer lengths and effective stress transfer at the interface achieved through surface functionalization of the reinforcements, fabricated bulk composites exhibited enhanced mechanical performance as compared to neat epoxy. Furthermore, governed flake pull-out mode along with a highly torturous crack path, which resulted from extensive deflection and meandering of the advancing crack around well-aligned high aspect ratio C-glass flakes, have led to high work-of-fracture values similar to nacre.

  20. SEISMIC Analysis of high-rise buildings with composite metal damper

    Directory of Open Access Journals (Sweden)

    Chen Ruixue

    2015-01-01

    Full Text Available This paper mainly studies on the mechanical characteristics and application effect of composite metal damper in the high-rise buildings via the numerical simulation analysis. The research adopts the elastic and elastic-plastic dynamic approach and the displacement time history response and damper energy dissipation capacity and so on of the high-rise building are compared and analyzed before and after installation. The analysis found that the energy dissipation characteristic of metallic dampers is good. High-rise building story drift significantly is reduced and the extent of damage of the walls and coupling beams is decreased, achieved a good energy dissipation effect. Composite metal damper can effectively and economically improve the seismic performance of high-rise buildings, meet the requirement of the 3-level design for seismic resistance. The result has certain reference significance for the application of metallic damper in the high-rise buildings.