Classic and recent results for gauge effects on the properties of the normal-to-superconducting phase transition in bulk and thin film superconductors are reviewed. Similar problems in the description of other natural systems (liquid crystals, quantum field theory, early universe) are also discussed. The relatively strong gauge effects on the fluctuations of the ordering field at low spatial dimensionality D and, in particular, in thin (quasi-2D) films are considered in details. A special attention is paid to the fluctuations of the gauge field. It is shown that the mechanism in which these gauge fluctuations affect on the order of the phase transition and other phase transition properties varies with the variation of the spatial dimensionality D. The problem for the experimental confirmation of the theoretical predictions about the order of the phase transitions in gauge systems is discussed.
Tunneling spectroscopy of normal-insulator-superconductor junction is investigated theoretically. In anisotropic superconductors, differently from the case of isotropic superconductor, the effective pair potentials felt by quasiparticles depend on the direction of their motion. By taking this effect into account, it is shown that the conductance spectra strongly depend on the crystal orientation. Using Green`s function method, local density of states (LDOS) in superconductor is also calculated. The close relation between conductance spectra and LDOS is presented. The calculation is compared with experimental spectra of high-{Tc} superconductors.
This paper reports Palladium alloy compositions investigated for suitability as a nonreactive material for the processing of ceramic superconductors. Barium-based superconductors were tested on Pd-Au and Pd-Ag alloys for reactivity. Bismuth-based superconductors were tested on a Pd-Ag alloy. The least reactive was found to be 70% Pd-30% Ag for the barium-based high-temperature superconductors (HTSC), whereas 30% Pd-70% Ag was found to be least reactive for bismuth-based HTSC.
We consider a Bose-Einstein condensate (BEC) of N atoms of repulsive interaction #approx# U_0, in an elliptical trap, axially pierced by a Gaussian-intensity laser beam, forming an effective (quasi-2D) toroidal trap with minimum at radial distance #rho# = #rho#_p. The macroscopic angular momentum states #PSI#_l(#rho#,#theta#) #approx# #sq root#N#PHI#_l(#rho#)e"i"l"#theta# for integer l spread up to #rho# > #rho#_p. The spreading lowers rotational energies, so estimated low metastability barriers can support large l < or approx. l_m_a_x #approx# (NU_0)"1"/"4, < or approx. 10 for typical parameters. The l-dependent density profile module #PHI#_l(#rho#)"2 -#PHI#_0(#rho#)"2 is a signature of BEC rotation. Results are insensitive to off-axis laser displacements #rho#_0, for #rho#_0 #rho#_m_a_x << 1. (author).
We review the interplay of frustration and strong electronic correlations in quasi-two-dimensional organic charge transfer salts, such as k-(BEDT-TTF)_2X and Et_nMe_{4-n}Pn[Pd(dmit)2]2. These two forces drive a range of exotic phases including spin liquids, valence bond crystals, pseudogapped metals, and unconventional superconductivity. Of particular interest is that in several materials there is a direct transition as a function of pressure from a spin liquid Mott insulating state to a superconducting state. Experiments on these materials raise a number of profound questions about the quantum behaviour of frustrated systems, particularly the intimate connection between spin liquids and superconductivity. Insights into these questions have come from a wide range of theoretical techniques including first principles electronic structure, quantum many-body theory and quantum field theory. In this review we introduce the basic ideas of the field by discussing a simple ...
This report discusses the following topics on superconductivity: nonlinearities in hard superconductors such as surface impedance of a type II superconductimg half space and harmonic generation and intermodulation due to alternating transport currents; and nonlinearities in superconducting weak links such as harmonic generation by a long Josephson Junction in a superconducting slab.
Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs.
A brief review is given of the nature of lattice instabilities in high-T/sub c/ superconductors. The Frohlich instability in A-15 compounds is indicated to be a microdomain which acts as an embryo for the Martensitic transformations in these compounds.
We propose triplet superconductors, such as ruthenates, as prospective materials for qubit construction. The vectorial nature of the order parameter in triplet superconductors makes it conceptually easy to estimate the performance of the qubits. The Cooper condensate of pairs in triplet superconductors has all the attributes of Bose-Einstein condensates and should facilitate long decoherence times for these qubits, relative to other vectorial schemes for qubits, such as small ferromagnets. There are other benefits, which the superconducting state provides for requirements such as entanglement between qubits via the proximity effect, etc. We consider these benefits in detail, although our consideration is only preliminary and further experimental and theoretical research will undoubtedly introduce correctives.
... Abstract : The inherent brittleness of the A-15 compounds, and the requirement for a filamentary morphology, led to a heavy reliance on a powder ...
A method of preparing a high temperature superconductor from an amorphous phase. The method involves preparing a starting material of a composition of Bi.sub.2 Sr.sub.2 Ca.sub.3 Cu.sub.4 Ox or Bi.sub.2 Sr.sub.2 Ca.sub.4 Cu.sub.5 Ox, forming an amorphous phase of the composition and heat treating the amorphous phase for particular time and temperature ranges to achieve a single phase high temperature superconductor.
The results of this research centered on the experimental studies of a single superconducting persistent current qubit, the implementation of type-II algorithms using these qubits, and the proposal for adiabatic quantum computing using these qubits. The m...
Development of useful high-critical-temperature (high-{Tc}) superconductors requires synthesis of superconducting compounds; fabrication of wires, tapes, and films from these compounds; production of composite structures that incorporate stabilizers or insulators; and design and testing of efficient components. This report describes technical progress of research and development efforts aimed at producing superconducting components based on the Y-Ba-Cu, Bi-Sr-Ca-Cu, Bi-Pb-Sr-Ca-Cu, and Tl-Ba-Ca-Cu oxides systems. Topics discussed are synthesis and heat treatment of high-{Tc} superconductors, formation of monolithic and composite wires and tapes, superconductor/metal connectors, characterization of structures and superconducting and mechanical properties, and fabrication and properties of thin films. Collaborations with industry and academia are also documented. 10 figs.
In the present study the Pb content in Bi(2223) phase by regression or curve fitting method are optimized. The best fitting curve can be obtained by the method of least square. To study the effect of Pb content in Pb substituted Bi (2223) superconductors, prepared by solid state reaction method data is obtained. The deviation of T_c from the target value for different Pb content is summarized
Multifilamentary superconductors with 2.5 micron sized NbTi filaments are being proposed for the High Energy Booster part of the SSC project. The small filament size and the large number of filaments in the superconductor strands make the fabrication a challenge, especially in view of the high critical current performance required of them. IGC has produced two 309 mm diameter prototype billets and fabricated both the 'Inner' and the 'Outer' grade strands. The production approach was based on a triple extrusion process incorporating Cu-0.6 st.% Mn as the interfilament matrix material. The results of this pilot development effort, in terms of critical current density and mechanical properties, are presented in this paper. Appropriate comparisons with past performances are made.
The controlled growth of nanowires (NWs) with dimensions comparable to the Fermi wavelengths of the charge carriers allows fundamental investigations of quantum confinement phenomena. Here, we present studies of proximity-induced superconductivity in undoped Ge/Si core/shell NW heterostructures contacted by superconducting leads. By using a top gate electrode to modulate the carrier density in the NW, the critical supercurrent can be tuned from zero to greater than 100 nA. Furthermore, discrete sub-bands form in the NW due to confinement in the radial direction, which results in stepwise increases in the critical current as a function of gate voltage. Transport measurements on these superconductor-NW-superconductor devices reveal high-order (n = 25) resonant multiple Andreev reflections, indicating that the NW channel is smooth and the charge transport is highly coherent. The ability to create and control coherent superconducting ordered states in ...
In these lecture notes we derive a generic holographic string theory realization of a p-wave superconductor and superfluid. For this purpose we also review basic D-brane physics, gauge/gravity methods at finite temperature, key concepts of superconductivity and recent progress in distinct realizations of holographic superconductors and superfluids. Then we focus on a D3/D7-brane construction yielding a superconducting or superfluid vector-condensate. The corresponding gauge theory is 3+1-dimensional N=2 supersymmetric Yang-Mills theory with SU(N) color and SU(2) flavor symmetry. It shows a second order phase transition to a phase in which a U(1) subgroup of the SU(2) symmetry is spontaneously broken and typical superconductivity signatures emerge, such as a conductivity (pseudo-)gap and the Meissner-Ochsenfeld effect. Condensates of this nature are comparable to those recently found experimentally in p-wave superconductors ...
The federating theme of superconductivity has given rise to a number of experimental studies of point defects in solids as different as transition metals (V, Nb, ...), A-15 compounds (V{sub 3}Si, Nb{sub 3}Ge, ...), or perovskite-like copper oxides. Some of these experiments are presented here. (orig.).
The federating theme of superconductivity has given rise to a number of experimental studies of point defects in solids as different as transition metals (V, Nb, ...), A-15 compounds (V_3Si, Nb_3Ge, ...), or perovskite-like copper oxides. Some of these experiments are presented here. (orig.).
This patent describes a method comprising applying a passivation layer of CaF{sub 2} to the surface of a superconductive ceramic oxide by evaporation. The CaF{sub 2} layer is effective to passivate the oxide surface without disrupting the superconductive properties.
A new empirical expression is presented for the T/sub c/ of A-15 compounds, T/sub c/ = 210 2R/sub A/-d/sub 0//R/sub B/..sqrt..M/sub A/ x R/sup 3//sub A/g-barZ-bary/sub B//RB/R/sup 3//sub B/n-baray/sub A//R/sub A/, from which the effects of some structural factors on T/sub c/ for high-T/sub c/ superconductors are obvious.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high {Tc} superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high T_c superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high [Tc] superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
In general there are actually two different types of A-15 compounds (A_3B) whose superconducting properties depend on whether the B atoms are transition elements (s-d type) or nontransition elements (s-p type). The properties in which the s-d type superconductors show marked differences in behavior from the s-p type include: (1) stoichiometry and range of composition, (2) the strong influence of N(O) on the stability and T/sub c/ of the phase, and (3), the effect of composition and atomic ordering on the T/sub c/ of the phase. These differences are discussed and a conclusion presented.
We discuss how magnetic phenomena affect superconductivity in simple metals, transition metals and alloys thereof, and dilute Rare-Earth alloys. It is shown both qualitatively and quantitatively that superconductors are sensitive probes for studying itinerant spin excitations, local spin excitations associated with nearly magnetic impurities, the effect of the atomic environment on the stability of local magnetic moments, and the nature of the spin order in Rare-Earth alloys. Also, we discuss how magnetic impurities can be used to study the electronic configuration which is responsible for superconductivity in Laves-phase crystals like A-15 compounds and ..beta..-W crystals, for example.
This paper presents a new method for the determination of the energy gap of superconductors. The V/sub max//kT versus ..delta../kT curve was calculated from tunneling theory. The maximum voltage in differential conductance V/sub max/ was measured from the electron tunneling spectrum. From V/sub max//kT and the curve, one can easily calculate the energy gap value ..delta... This method is simple, and the accuracy almost approaches that of the curve-fitting method.
This paper presents a new method for the determination of the energy gap of superconductors. The V/sub max//kT versus #DELTA#/kT curve was calculated from tunneling theory. The maximum voltage in differential conductance V/sub max/ was measured from the electron tunneling spectrum. From V/sub max//kT and the curve, one can easily calculate the energy gap value #DELTA#. This method is simple, and the accuracy almost approaches that of the curve-fitting method.
A new method for determining the energy gap of a superconductor using the maximum in the differential conductance curve of electron tunneling spectrum is given in this paper. The V/sub max//kT versus ..delta../kT curve was calculated from tunneling theory. V/sub max/, the voltage of the conductance maximum, can be measured from electron tunneling spectrum. ..delta../kT can be found from this curve, then the energy gap ..delta.. can be calculated. This method is simple, fast and accurate. The accuracy almost approaches that of the curve fitting method.
The A-15 compounds with the highest critical temperatures and critical fields are stable only at high temperatures and sometimes are not stable at any temperature. Fabrication of such materials thus necessarily involves the creation and manipulation of metastable phases. It follows that the bronze matrix technique now under development for Nb_3Sn- and V_3Ga-based composite superconductors is not suitable for high-T/sub c/ materials of the Nb_3 (Al, Ge, Ga, Si) family. Alternative technologies will be necessary for such materials. Efforts to develop suitable alternatives, using Nb_3Al, are described.
The characteristics of the temperature dependence of the upper critical magnetic field, Hc2(T), of structurally inhomogeneous superconductors (e.g., ternary molybdenum chalcogenides, A-15 compounds, transition metal alloys, and amorphous films) are investigated analytically. The MWGH equation for Hc2(T) is generalized to the case of weakly inhomogeneous systems with a characteristic inhomogeneity scale much smaller than the effective coherence length. It is shown that an increase in the dispersion of the diffusion coefficient leads to an increase in the slope and width of the linear section of the Hc2(T) curve. 11 references.
In this paper, we review some of the work our group has done in the past few years to obtain the electron self-energy of high temperature superconductors by analysis of angle-resolved photoemission data. We focus on three examples which have revealed: (1) a d-wave superconducting gap, (2) a collective mode in the superconducting state, and (3) pairing correlations in the pseudogap phase. In each case, although a novel result is obtained which captures the essence of the data, the conventional physics used leads to an incomplete picture. This indicates that new physics needs to be developed to obtain a proper understanding of these materials.
In one of the first uses of high Tc superconductors in an end-use product, Lake Shore Cryotronics and a Swiss lab have developed a liquid nitrogen level sensor using a high Tc thin film. The probe is manufactured using a seamless stainless steel tube with an yttrium-based zirconium oxide flame-sprayed on the tube. A plasma-sprayed superconductor compound is deposited on top of that. The probe is coated with a sealant that protects the superconducting film from the atmosphere. This manufacturing method has yielded an extremely durable product. Unaffected by ice formation and related mechanical problems, the superconducting level sensor can be kept in the dewar for long periods of time.
The vomeronasal organ is the primary olfactory organ that detects sexual pheromones in mammals. We investigated the anatomy of the vomeronasal organ of the tammar wallaby (Macropus eugenii),...Full Text Available
We have investigated the superconducting and metallurgical properties of the ternary compounds RPd_2Si_2 and RRh_2Si_2 with R = Y, La, and Lu. All RPd_2Si_2 compounds and LaRh_2Si_2 were found to be type-I superconductors below 1 K. A detailed metallurgical analysis shows that segregation of second phases can easily mask the intrinsic (stoichiometric ratio 1:2:2) intermetallic-compound properties. Two sample-preparation techniques, viz., single crystals and off-stoichiometry, were utilized to establish where bulk superconductivity occurs. The type-I behavior of these compounds is explained with an analogous model as is used for the heavy-fermion superconductors CeCu_2Si_2 and URu_2Si_2.
The proposed Superconducting Super Collider (SSC) in the US and plans for a Large Hadron Collider LHC at CERN are likely to require micron size filaments to reduce micron size filaments to reduce magnetization effects at the low injection fields envisioned. Superconductors of NbTi, designed to meet these requirements, are described. These conductors contain from 6000 to 36,613 filaments. Results are presented on NbTi conductors made by multiple extrusion techniques. Filament sizes of between 2.2 and 17 micron have been obtained. Current densities of between 2400 A/mm"2 and nearly 3400 A/mm"2 at 5 Tesla have been achieved. Metallurgical aspects of these conductors are presented using both optical and SEM views of conductor cross section and filament surface.
Recent progress in yttrium-based oxide high-temperature superconductors has enabled the production of a large diameter bulk with a strong flux-pinning force. A combination of this superconductor and a permanent magnet makes it feasible to fabricate a noncontact, non-controlled superconducting magnetic bearing with a very small rotational loss, applicable to a flywheel energy storage system. A conceptual design of an 8 MWh flywheel energy storage system using the new bearing has been developed, based on measured data on a miniature bearing model, which proved to be potentially capable of achieving a high energy storage efficiency of 84 pc. A 100 W h-class experimental system was then built, which attained a high revolution rate of 17000 rpm, with a rotational loss of about 0.6 W. (authors). 2 refs., 7 figs., 3 tabs.
Our previous point-contact Andreev reflection studies of the heavy-fermion superconductor CeCoIn{sub 5} using Au tips have shown two clear features: reduced Andreev signal and asymmetric background conductance. To explore their physical origins, we have extended our measurements to point-contact junctions between single crystalline heavy-fermion metals and superconducting Nb tips. Differential conductance spectra are taken on junctions with three heavy-fermion metals, CeCoIn{sub 5}, CeRhIn{sub 5}, and YbAl{sub 3}, each with different electron mass. In contrast with Au/CeCoIn{sub 5} junctions, Andreev signal is not reduced and no dependence on effective mass is observed. A possible explanation based on a two-fluid picture for heavy fermions is proposed.
Our previous point-contact Andreev reflection studies of the heavy-fermion superconductor CeCoIn{sub 5} using Au tips have shown two clear features: reduced Andreev signal and asymmetric background conductance. To explore their physical origins, we have extended our measurements to point-contact junctions between single crystalline heavy-fermion metals and superconducting Nb tips. Differential conductance spectra are taken on junctions with three heavy-fermion metals, CeCoIn{sub 5}, CeRhIn{sub 5}, and YbAl{sub 3}, each with different electron mass. In contrast with Au/CeCoIn{sub 5} junctions, Andreev signal is not reduced and no dependence on effective mass is observed. A possible explanation based on a two-fluid picture for heavy fermions is proposed.
The dynamic response of cylindrical and ring-shaped YBaCuO bulk parts to pulsed magnetic fields is calculated by using small sets of finite elements. Some comparisons with experimental results are provided, and they give confidence in the modelling of the superconducting properties. Transient magnetizations as a function of time and space as well as shapes and absolute values of trapped magnetic flux profiles are presented. The influence of the sample geometry is investigated for different millisecond pulsed magnetization processes. Results are reported for different radial thicknesses and heights, different pulse durations, peak magnetic fields and pulse sequences with and without stepwise cooling. Comparisons concerning the achievable trapped magnetic field and flux are made, and implications for the use of high-temperature superconductor bulk parts as cryo-permanent magnets in potential applications like electric machinery are discussed.
The effects of intradot electron-electron interaction on the photon-assisted Andreev tunneling of a superconductor/carbon-nanotube/superconductor system are studied by using nonequilibrium Green's function technique. The inverse supercurrent reflecting the #pi#-junction transition emerges in the spin-split energy-levels regime polarized by the Coulomb interaction. For the positive tunneling case, the supercurrent reaches its maximum when the spin-degenerate energy-levels are nearest to the Fermi surface. Conversely, for the negative tunneling case, the supercurrent reaches its maximum when two split energy-levels are symmetric with respect of the Fermi surface. The sign and the amplitude of the Andreev tunneling depend distinctly on the energy-level spacing tuned by photon-assisted tunneling. In order to fully understand the transport characteristics, the current-carrying density of states are investigated, which clearly shows the enhancement, suppression or even ...
Spectroscopy based on the Andreev reflection (AR) process at the interface between the normal metal tip and the superconductor has become one of the very successful methods for studies in novel exotic superconductors. The method is capable to address the size, symmetry as well as multiplicity of the superconducting order parameter. The method provided one of the first evidences of the two-gap superconductivity in MgB{sub 2} with a detailed temperature dependence of the both gaps. A theory treating the Andreev reflection spectroscopy in the mixed state is missing. We analyse the AR spectra of MgB{sub 2} in the mixed state via modelling the magnetic pair-breaking by the increasing spectral broadening parameter {gamma}. As a result a non-trivial pair breaking effect in the {pi}-band is found.
Although hydrogen is the simplest of atoms, it does not form the simplest of solids or liquids. Quantum effects in these phases are considerable (a consequence of the light proton mass) and they have a demonstrable and often puzzling influence on many physical properties, including spatial order. To date, the structure of dense hydrogen remains experimentally elusive. Recent studies of the melting curve of hydrogen indicate that at high (but experimentally accessible) pressures, compressed hydrogen will adopt a liquid state, even at low temperatures. In reaching this phase, hydrogen is also projected to pass through an insulator-to-metal transition. This raises the possibility of new state of matter: a near ground-state liquid metal, and its ordered states in the quantum domain. Ordered quantum fluids are traditionally categorized as superconductors or superfluids; these respective systems feature dissipationless electrical currents or mass flow. Here we report an ...
... In order to produce organic livestock feed, feed mills must be inspected and certified. If they produce both organic and non-organic feed, they must implement procedures, backed up by records, to prevent the commingling of organic and non-organic feed. This includes steps to clean storage bins and mixing and bagging equipment prior to producing batches of organic feed. Organic feed mills also must prevent ...
It is shown that thermodynamic properties can be used to determine whether, the degradation in Tsub(c) with increasing disorder observed in some A-15 compounds, is due to a reduction in electronic density of states and/or electron-phonon interaction or is due instead to an increase in Coulomb repulsion ..mu..* coming from increased localization as suggested by Anderson et al.
The defect-induced effect on superconducting transition temperature T_c of A-15 compounds is examined. T_c is found from the Eliashberg equations which take into account the defect-induced changes in the electron-phonon spectral function and electron density of states. The dependence of T_c on the defect type in the superconductor is obtained.
Structural instabilities are now being found in many high-temperature superconductors. Compounds with the A-15 (#beta#-W) structure comprise the most important group of these materials, and their properties have been extensively studied for over 15 years. A review is given of some of these results, particularly those relating to the elastic behavior. The empirical relation of the structural instability and the anharmonicity to the high superconducting transition temperature is discussed.
A brief article gives an update on the commercial exploitation of superconductivity by the American Superconductor Corporation. Potential applications include transmission and distribution, motors, magnetic storage systems, current limiters and transport. The company have produced a kilometre long, ''wrappable'' cable capable of carrying thousands of amps when operating at a temperature of below -140[sup o]C. (UK)
It is suggested that the large reduction of the superconducting transition temperature Tc due to defects observed experimentally in some A-15 compounds is caused by smearing of a high peak in the density of states at the Fermi level. The influence of defects on other physical properties (the magnetic susceptibility ?, the elastic modulus Cs, the structural transformation temperature Tm and the electrical resistivity ?) is also discussed from the same point of view. We expect the anomalous temperature dependence of ?, Cs and ? will be suppressed by defects.
Partial Contents: Ternary Compounds; Granular Superconductors; Superconductivity in (SN)x and its Halogen Derivative (SNBr0.4)x; Studies of cuCl at Elevated Pressures; Superconducting Properties of Hydride Systems; Thin Film Superconducting Materials Research; Synthesis of Superconducting Nb3Si using High Pressures; Synthesis of Unstable A-15 Compounds by Epitaxial Recrystallization of Ion Implanted Layers; and Sputtering of Nb3Si.
The structural instability in high temperature A-15 superconductors is examined from a phenomenological, Landau theoretic point of view, based on the picture of an electronically driven lattice instability. emphasis is given to lattice properties--in particular, the extended softening of phonons in k-pace and phonon linewidth. Implications of the extended softening on the microscopic picture of the transition, and the interplay between structural and superconducting instabilities in the A-15 compounds are discussed.
A review of the information on the electron and phonon spectra in the A-15 compounds and Chevrel phase superconductors obtained from nuclear magnetic resonance, heat capacity, and Moessbauer effect experiments is presented. Relationships of the Fermi energy electrons and the soft phonons to the strength of the electron-phonon interaction are discussed.
A review of the information on the electron and phonon spectra in the A-15 compounds and Chevrel phase superconductors obtained from nuclear magnetic resonance, heat capacity, and Moessbauer effect experiments is presented. Relationships of the Fermi energy electrons and the soft phonons to the strength of the electron-phonon interaction are discussed.
Radionuclide x-ray fluorescence analysis was used for the determination of Y, Ba and Cu in thin high-temperature superconducting films. Atomic emission ICP spectrometry was used to estimate the precision and accuracy of analytical results. Reasonable agreement between both methods was obtained when a polynomial calibration curve was applied. (author) 4 refs.; 4 tabs.
Recently, organic semiconducting materials have gained a broad interest due to their potential for organic electronic devices such as organic light emitting diode (OLED), organic photovoltaic devices and organic field-effect transistors (OFETs). Optical properties of organic semiconducting materials are important for practical application. For example, the power conversion efficiency of organic photovoltaic devices is mainly affected by absorption properties of organic materials. Proton irradiation is one of the efficient methods to change the optical properties of organic materials. In this paper, we investigate the changes of optical properties of various polymers using the proton irradiation.
This paper addresses one source of degradation in OPV devices: the metal/organic interface. The basic approach was to study the completed device stability vs. the stability of the organic film itself as shown in subsequent devices fabricated from the films.
Nitrogens, Sulfurs, Isotopes, and Hydrocarbons Gases Elements Ions and Inorganic Acids Organic Compounds Co-eluting Organics Hopanes, Cholestanes, and Sterols Pesticides,...
We have investigated the superconducting and metallurgical properties of the ternary compounds RPd/sub 2/Si/sub 2/ and RRh/sub 2/Si/sub 2/ with R = Y, La, and Lu. All RPd/sub 2/Si/sub 2/ compounds and LaRh/sub 2/Si/sub 2/ were found to be type-I superconductors below 1 K. A detailed metallurgical analysis shows that segregation of second phases can easily mask the intrinsic (stoichiometric ratio 1:2:2) intermetallic-compound properties. Two sample-preparation techniques, viz., single crystals and off-stoichiometry, were utilized to establish where bulk superconductivity occurs. The type-I behavior of these compounds is explained with an analogous model as is used for the heavy-fermion superconductors CeCu/sub 2/Si/sub 2/ and URu/sub 2/Si/sub 2/.
Recently we have found a highly effective additive for the melt growth processings attaining high critical currents in YBCO superconductor. It is platinum and it behaves as an effective grain growth inhibitor for the Y{sub 2}BaCuO{sub 5} phase. Even with less than 1 wt.% doping, Y{sub 2}BaCuO{sub 5} particles becomes less than one micron in size and distribute themselves to become homogeneously embedded in the large grown YBa{sub 2}Cu{sub 3}O{sub y} grains. The sample shows large magnetic hysteresis and a typical J{sub c} value estimated by using Bean's model critical state model is 18000 A/cm{sup 2} at 77 K and 1 T. We found that rhodium has a similar remarkable effect. (orig.).
We report ab initio calculations of positron wave functions in the high-T/sub c/ superconductors YBa_2Cu_3O_7, Bi_2Sr_2CaCu_2O_8, and Tl_2Ba_2CaCu_2O_8 using the general potential linearized augmented plane-wave method. The calculated positron wave functions are fairly insensitive to whether or not electron-positron correlation is included in the calculation for YBa_2Cu_3O_7 and Tl_2Ba_2CaCu_2O_8, but the calculated positron density is quite sensitive to correlation in Bi_2Sr_2CaCu_2O_8. While the positron wave function samples primarily the chain region in YBa_2Cu_3O_7, the results indicate that positrons should be good probes of the Cu-O layer-derived electronic states near the Fermi energy in Tl_2Ba_2CaCu_2O_8 since a large overlap with these states is predicted.
The authors have measured the magnetization of single-phase 90-K superconductors, GdBa_2Cu_3O/sub 6+#delta#/, EuBa_2Cu_3O/sub 6+#delta#/, and SmBa_2Cu_3O/sub 6+#delta#/ with a SQUID magnetometer. They have shown that, in the superconducting state, each magnetization-field curve exhibits a maximum at #approx# 100 G, followed by a linear increase of the magnetization with a slope only approximately one-fifth of the slope for a field smaller than 50 G. They have also investigated the effect of #gamma#-irradiation on YBa_2Cu_3O/sub 6+#delta#/, SmBa_2Cu_3O/sub 6+#delta#/, and have found that the radiation damage results in the appearance of a tail in the superconducting transition. They have also shown that the normal resistance decreases with increasing radiation exposure up to a dose of 10 Mrad.
A technique and a particular apparatus for an inductive measurement of critical currents as a function of temperature and magnetic field in thin-film superconductors are described. The technique has been found to be particularly useful for high-field A-15 compounds 2 to 3 ..mu..m thick. Samples with lower critical current densities would have to be correspondingly thicker to measure over the same broad range of temperature and field. The design of the apparatus is detailed showing that the film can be taken directly from the deposition chamber and mounted without electrical contacts so samples can be changed easily. The principles of operation are developed based on the Critical State Model. These principles are tested by measurements which verify that the measured value of critical curent is independent of the amplitudes and frequency of the small ac magnetic field which is added to a much larger quasistatic field. The inductive measurements are compared with ...
Focused ion beam (FIB) processes have been developed for Y--Ba--Cu--O superconductor films. A Y--Cu liquid metal ion source has been fabricated, using a Y_6_7 --Cu_3_3 eutectic alloy as the ion source. As-sputtered Y--Ba--Cu--O film etch rate ratios to GaAs(100) and Si(100) substrates are 0.28 and 1.4 for 130-keV Au"+ FIB ion etching, respectively. Y--Ba--Cu--O submicron patterns have been demonstrated by using FIB lithography and Cl_2 reactive ion beam etching. Moreover, a Y--Ba--Cu--O superconducting line with 4-#mu#m linewidth has been fabricated by annealing an as-sputtered Y--Ba--Cu--O line pattern. T/sub c/ control of Y--Ba--Cu--O film has been achieved by 200-keV Ne"+, using conventional ion implantation and 300 keV Si"+"+ FIB ion implantation.
The passive films formed on iron metal, alloys or stainless steel are extremely thin oxides or hydroxides and possess the properties of high chemical stability in the environment. These films show characteristics interested both electrical as well as electrochemical point of view due to the thin thickness of the films. Auger Electron Spectroscopy, X-ray Photoelectron spectroscopy and so on which are the conventional electrochemical measurement methods or the surface analysis methods are used for the analysis and evaluation of these films, however, at present, the application of research technique focusing the superconductor characteristics of the films are tried. Although, the potential modulation reflection spectroscopy method has merits like possibility of in-situ measurement, high precision, possibility of stable analysis even for extremely thin film and so forth, it has also demerits like difficulty to response the potential modulation of hydroxides and also ...
This paper reports on superconductor-semiconductor-superconductor (S-N-S) weak-link junctions with the normal layer of Si or InSb thin films were prepared by using focused ion beam (FIB), and electrical properties were measured. Whereas InSb thin films on single crystals did not have an intrinsic mobility, S-N-S junction with InSb shows the characteristics of Josephson S-N-S junction. A 200nm-thick film of InSb deposited on MgO had a mobility of 83 cm{sup 2}.V {center dot} s and a carrier density of 6.5 {times} 10{sup 17} cm{sup {minus}3} at 4.2K. The coherence length {xi}{sub n} was computed to be 17 nm from these experimental data, and we obtained critical superconducting current Ic of 100 {mu} A for the S-N-S junction which had a line width of 10{mu} m and a channel length of 20 nm.
Gantries in the proton/carbon cancer therapy machines represent the major cost and are of the largest size. This report explains a new way to the gantry design. The size and cost of the gantries are reduced and their use is simplified by using the fixed magnetic field. The ''new'' gantry is made of a very large momentum acceptance non-scaling Fixed Field Alternating Gradient (FFAG) quarter and half arc beam lines. The gantry is made of combined function magnets with a very strong focusing and small dispersion function. Additional magnets with a fast response are required to allow adjustments of the beam position for different energies at the beginning of the gantry. Additional strong focusing magnets following the gantry have also to be adjustable to provide required spot size and radial scanning above the patients. The fixed field combined function magnets could be made of small permanent magnets for the proton machine, or of the high temperature ...
For spintronic applications it is important to establish how efficiently spins can be injected from a magnetic material into a non-magnetic material and the distance over which those spins survive. It is thought that spin polarised transport current can be determined by using the suppression of the Andreev reflection between a superconductor and the spin polarised material (Science 282 (1998) 85). Cu/Co bilayers are potentially an ideal test system for such study. In this paper we assess the feasibility of using point contact Andreev reflection spectroscopy to address this problem using a superconducting niobium tip at 4.2 K.
YBa_2Cu_3O_7_-_x thick films have been deposited on silver sheets and MgO single crystals by spray pyrolysis. Film texture is related to film thickness and sintering temperature. The X-ray intensity ratio of the 005 peak to the 110 peak is higher for thin films deposited at the higher temperatures. However, elevated temperatures promote copper diffusion and second-phase formation in films deposited on silver. Films deposited on MgO can have larger grain sizes and are more oriented than those deposited on silver.
A discussion of some of the difficulties with previous analyses of the resistivity of A-15 compounds is given. Precise high-temperature data on ..cap alpha..-particle- and electron-damaged Nb/sub 3/Ge and Nb/sub 3/Sn samples with different defect concentrations are presented here and analyzed in a simple way with use of a phenomenological model based on the idea that the ideal resistivity must approach some limiting value in the regime where the mean free path becomes comparable to the interatomic spacing.
It is suggested that the large reduction of the superconducting transition temperature T sub(c) due to defects observed experimentally in some A-15 compounds is caused by smearing of a high peak in the density of states at the Fermi level. The influence of defects on other physical properties (the magnetic susceptibility chi, the elastic modulus C sub(s), the structural transformation temperature T sub(m) and the electrical resistivity rho) is also discussed from the same point of view. We expect the anomalous temperature dependence of chi C sub(s) and rho will be suppressed by defects. (auth.).
The mission of the Midwest Superconductivity Consortium, MISCON, is to advance the science and understanding of high {Tc} superconductivity. During the past year, 27 projects produced over 123 talks and 139 publications. Group activities and interactions involved 2 MISCON group meetings (held in August and January); with the second MISCON Workshop held in August; 13 external speakers; 79 collaborations (with universities, industry, Federal laboratories, and foreign research centers); and 48 exchanges of samples and/or measurements. Research achievements this past year focused on understanding the effects of processing phenomena on structure-property interrelationships and the fundamental nature of transport properties in high-temperature superconductors.
We review 25 specific heat measurements performed in Geneva on binary and pseudo-binary A-15 compounds. The rather extended temperature range allows us to make reliable estimates of several moments of the phonon spectrum which are required in the theory of superconductivity. The Tsub(c) expression of Allen and Dynes can then be used consistently to estimate the microscopic parameters lambda, eta, Nsub(bs) (Esub(F)), etc. The broad range of values reviewed permits to establish significant correlations between the parameters in stoichiometric and ordered compounds. (orig.).
Recently, a superconducting cryo-electron microscope in which specimens are cooled to the liquid helium temperature (4.2 K) has been developed. The main components and functional features of this new microscope are reported together with application data on polyethylene, poly (4-methyl-1-pentene), valonia cellulose, rock salt, ice crystallites and ceramic superconductor. The resistance to electron radiation damage, of beam-sensitive specimens including polymers has been increased more than ten times. Thus, the microscope has made it possible to take high resolution images and to analyze the crystal-structure of micro-areas. (orig.).
Measurements of the temperature dependence of the electrical resistivity and correlations observed with T/sub c/ for V_3Si, V_3Ge, and A-15 Nb-Ge show (i) the existence of a universal defect in the A-15 superconductors which is not nonstoichiometry, (ii) a normal state anomaly also strongly influenced by the defects, and (iii) evidence that T/sub c/ and the electron-phonon interactions for transport processes are approx.100 times more sensitive to defect producing sample modifications in the A-15 compounds than in Nb.
High energy ion backscattering analysis in combination with recently-developed resonance scattering analysis is described, with a stress on precise and quantitative oxygen analysis and its successful application to the characterization and quality estimation of high T_c oxide superconductors. Particularly, the present status of high energy ion backscattering analysis, the review of analytical results for YBa_2Cu_3O_7 _- _x, the estimation of composition and crystalline quality of (La_1 _- _xSr_x)_2CuO_4 by 7 MeV alpha particle backscattering analysis are described.
The baseline design for the SSC High Energy Booster (HEB) has dipole bending magnets with a 50 mm aperture. An analysis of the cryogenic heat load due to A.C. losses generated in the HEB ramp cycle are reported for this magnet. Included in this analysis are losses from superconductor hysteresis, yoke hysteresis, strand eddy currents, and cable eddy currents. The A.C. loss impact of 2.5 {mu}m vs. 6 {mu}m filament conductor is presented. A 60 mm aperture design is also investigated. 8 refs., 3 tabs.
Superconducting generators for high power applications have been of interest for a number of years. Superconducting generators using low temperature superconductors (LTS) have been manufactured to produce up to 20 MW of electrical power and have been configured in either synchronous alternators which have an AC output that may be subsequently rectified to produce DC and homopolar generators which produce low voltage DC. Typically these generators require scrupulous attention to vacuum integrity for cryogenic insulation at 4.2K and tend to be somewhat fragile because of extensive thermal and magnetic shields that are not required in conventional power generators. Recently, high purity aluminum composites have been developed for a high power AC generator that is cooled by cryogenic hydrogen at 21K. This aluminum generator is very compact and lightweight and is much more robust than a generator made with LTS because extensive thermal and magnetic shields are not ...
Maintaining uniformity of properties over long distances is one of the fabrication problems encountered with the new high {Tc} superconductors. Uniform properties are crucial in long tapes or wires with high critical current since local nonuniformities can limit the current carrying capacity of the whole piece. Transport critical currents in high {Tc} superconductors are conventionally measured with the contact 4-point probe DC current-voltage technique. This technique requires contact with the sample and and spatially averages over the region between the two voltage contacts. Two techniques have been used to infer the critical state model. The first uses the net magnetization of a suitably shaped sample in an external magnetic field. The second combines a DC magnetic field with AC induced currents to infer spatial flux profiles. The AC magnetization technique offers an advantage in that it is noncontacting; however, it also averages the ...
We review the current status of Andreev reflection spectroscopy on the heavy fermions, mostly focusing on the case of CeCoIn5, a heavy-fermion superconductor with a critical temperature of 2.3 K. This is a well-established technique to investigate superconducting order parameters via measurements of the differential conductance from nanoscale metallic junctions. Andreev reflection is clearly observed in CeCoIn5 as in other heavy-fermion superconductors. Considering the large mismatch in Fermi velocities, this observation seemingly appears to disagree with the Blonder-Tinkham-Klapwijk (BTK) theory. The measured Andreev signal is highly reduced to the order of maximum ?13% compared to the theoretically predicted value (100%). The background conductance exhibits a systematic evolution in its asymmetry over a wide temperature range from above the heavy-fermion coherence temperature down to well below the superconducting transition temperature. ...
The concentration of some organic acids in the atmosphere was determined using a wet effluent diffusion denuder-aerosol collector coupled with Ion Chromatography. Three organic acids and four inorganic anions were identified and quantified in the air sample, taken from the backyard of PSI. (author)
...In your area Get connected Farmers & growers news Training & events Poultry (laying) Poultry production can be a profitable enterprise for organic farmers and eggs are ... To find out more about organic poultry production download our free comprehensive introductory guide: Organic poultry production - an introductory guide [PDF, ...
... Do you certify Halal or Kosher meat? What fish feed do you allow? What levels of polychlorinated biphenyls (PCBs) have been found in organic fish? How can I be sure that organic products from abroad are really organic? Do you prosecute businesses that break the rules? Does the Soil Association carry out any routine testing of food? Do you test for GM material? Why do you allow additives in organic food? Is organic food fortified with vitamins and minerals? Why choose organic during pregnancy?...
... TITLE (Include Security Classification) Sorption of Selected Volatile Organic Constituents of Jet Fuels and Solvents on Natural Sorbents from Gas ...
Described as the body's largest organ, the skin is strategically located at the interface with the external environment where it has evolved to detect, integrate and respond to a diverse range...Full Text Available
Hypocalcemia in the hypomagnesemic state in man is usually attributed to refractoriness of end-organs to the calcemic action of parathyroid hormone. We studied the responsiveness of end-organs to bovine...Full Text Available
FT-IR spectroscopic studies of major organic matter in carbonaceous chondrites using microscopic technique and comparison with terrestrial kerogen. ...
This paper aims to explore consumer preference for fresh vegetables labelled as organic in combination with health and environment related quality traits. The study decomposes organic farming into its main quality aspects and measures consumers' preference structure for organic, in general, and for specific organic quality traits in particular. By means of stated choice preference modelling, the following hypotheses are tested: consumers prefer health over environment related quality traits; the organic label plays a significant role in consumers' choice for organic products; organic farming is perceived as healthier and more environmentally friendly than conventional farming; purchase intention is mainly driven by health related quality traits; both health and environmental concerns influ...
years I chaired a national committee drafting recommended standards for organic livestock production for the Organic Trade Association and had the opportunity to work with...
The study of the intrinsic behavior of high transition temperature copper-oxide superconductors (HTSC) has proven to be challenging because of the extreme sensitivity of their transport properties on material quality. These compounds are characterized by a high degree of structural and electrical anisotropy, and a very short superconductive coherence length of the same order as the size of the crystalline unit cell (~5-30 A). As a result, microscopic defects such as oxygen vacancies, cationic disorder, and the presence of minute impurities have a significant effect on electrical transport in these materials. Therefore, much effort has been expended in synthesizing sizable samples that are homogeneous, well characterized, and emenable to the study of the anisotropic properties of the HTSC. We have demonstrated that thin films of HTSC compounds such as rm YBa_2Cu_3O_{7 -delta}, which is a 92 K superconductor, can be synthesized easily by a ...
The frequency dependence of the tunneling spectrum #alpha#"2F (#omega#) is analyzed in terms of electron pairing induced by exchange of acoustic plasmons in addition to the usual phonon-exchange mechanism. Analytic expressions are obtained for the electron self-energy, the tunneling function #alpha#"2F, and the electron pairing coupling lambda which determines the superconducting properties. The resulting theory is applied to recent tunneling data of Nb_3Sn in order to examine the anomalous discrepancies with the phonon density of states found by neutron scattering experiments. The results demonstrate how the high-temperature (T/sub c/ approx. 20 "0K) superconducting properties of A-15 compounds are enhanced by acoustic-plasmon contributions, and thus they reconcile these high transition temperatures with the relatively small values of the phonon part of lambda estimated from several independent experiments.
The Fe-based copper oxide Formula Not Shown exhibits superconductivity around 50K only when it is properly annealed in Formula Not Shown atmosphere and subsequently in Formula Not Shown atmosphere. In contract Formula Not Shown does not exhibit superconductivity even if it is annealed along the same process as Formula Not Shown . We have synthesized the polycrystalline samples of Formula Not Shown solid solution system Formula Not Shown to investigate the Nd substitution effects. DC magnetization measurements have shown that, the samples in a range of Formula Not Shown exhibit superconductivity and Formula Not Shown was reduced with increasing the Nd content. However, we could not observe the superconductivity for Formula Not Shown and 1. Rietveld refinement results revealed that due to th...
The structural and electronic properties of the A-15 compounds Nb_3Rh and Nb_3Ir were studied by means of escalar relativistic full-potential linearized augmented-plane wave (FP-LAPW) calculations with generalized gradient corrections. An investigation of the band structure of the hypothetical Nb_3Nb compound was also performed at the theoretical equilibrium lattice constant to ascertain the contribution of the nontransition elements on the B site in these A_3B-type compounds. Band structures and total densities of states were obtained. A rough estimate of the electron-phonon coupling parameter #lambda# as well as of the electronic specific-heat coefficient #gamma# were obtained for both Nb_3Rh and Nb_3Nb, which confirms that this latter is a low-temperature superconductor with T_c - 10K.
The results on 5 K irradiation available so far may be summarized as follows. (1) Increases of j/sub c/ following neutron irradiation occur only in conductors which are far from the optimal metallurgical treatments. (2) The changes of j/sub c/ following neutron irradiation and a thermal cycle to room temperature are small and in most cases comparable to the results obtained after 77 K irradiation. (3) The data available so far indicate that the degradation of j/sub c/ at 8 T is larger by about 5 to 10% than the corresponding changes at 5 T at a neutron fluence of 1.3 x 10/sup 22/ m/sup -2/ (E > 0.1 MeV). (4) The increase of Cu-resistivity is significant even after a thermal cycle to room temperature and requires design changes for a stable magnet operation.
The universal depression of the superconducting transition temperature T/sub c/ in disordered A-15 compounds is examined. It is found that their anomalous behavior can be explained by a simple model for the density of states, which is enhanced by disorder in some cases. The dramatic drop in T/sub c/ in constant density-of-states A-15 compounds like Nb/sub 3/Ge or Nb/sub 3/Al at a critical value of the resistivity can be attributed to overdamping of acoustic plasmons, which decreases the electron pairing interaction despite relatively small changes in the density of states. Agreement for T/sub c/ and susceptibility chi with previous calculations is found of the position of the Fermi energy is near a peak. Possible experiments are proposed to check the above models.
The universal depression of the superconducting transition temperature T/sub c/ in disordered A-15 compounds is examined. It is found that their anomalous behavior can be explained by a simple model for the density of states, which is enhanced by disorder in some cases. The dramatic drop in T/sub c/ in constant density-of-states A-15 compounds like Nb_3Ge or Nb_3Al at a critical value of the resistivity can be attributed to overdamping of acoustic plasmons, which decreases the electron pairing interaction despite relatively small changes in the density of states. Agreement for T/sub c/ and susceptibility chi with previous calculations is found of the position of the Fermi energy is near a peak. Possible experiments are proposed to check the above models.
Superfluidity in fermionic systems originates from pairing of fermions, and Bose condensation of these so-called Cooper pairs. The Cooper pairs are usually made of fermions of different species; for example in superconductors they are pairs of electrons with opposite spins. Thus the most favorable situation for pairing and superfluidity is when the two species of fermions that form pairs have the same density. This paper studies the possible superfluid states when the two pairing species have different densities, and show that the resultant states have remarkable similarities to the phases of liquid crystals. This enables us to provide a unified description of the possible pairing phases, and understand the phase transitions among them.
This renewal request for DOE grant DE-FG02-86ER45238, is dedicated to providing a complete thermodynamic profile of solids fluids, and fluid mixtures, over a wide range of temperatures and pressures. We are partially motivated by technological interest in detonation, combustion, superhard high pressure materials, and high temperature superconductors, which are important components of interest of various DOE laboratories. Our work on fluids and solids, composed of simple molecules, involves the determination of structures, phase transitions, pressure-volume relations, phonon, vibron, and libron modes of excitation, sound velocities, specific heats, thermal expansion, virial coefficients, sublimation energies, and orientational translational, and magnetic correlations. We hope that the study of these systems under extreme thermodynamic conditions will lead to exotic new materials of value, as well as enhanced fundamental understanding.
The newly discovered oxypnictide family of superconductors show very high critical temperatures of up to 55 K. Whilst there is growing evidence that suggests a nodal order parameter, point contact Andreev reflection spectroscopy can provide crucial information such as the gap value and possibly the number of energy gaps involved. For the oxygen deficient NdFeAsO_0_._8_5 with a T_c of 45.5 K, we show that there is clearly a gap value at 4.2 K that is of the order of 7 meV, consistent with previous studies on oxypnictides with lower T_c. In addition, taking the spectra as a function of gold tip contact pressure reveals important changes in the spectra which may be indicative of more complex physics underlying this structure. (rapid communication)
We compare the effect of isotropic point defects vis a vis extended defects on the inter and intra grain properties of superconducting MgB{sub 2} thin films. In a recent paper Gandikota et al. [Appl. Phys. Lett. 86 (2005) 012508] reported that after 200 MeV {alpha} particle irradiation intergrain connectivity remains unaffected. Our results on the contrary indicate that connectivity does depend on irradiation dose and type of ions used. We ascertain that extended defects alter the {sigma} band properties of this two-band superconductor more effectively than the point defects. The improvement in upper critical field and critical current density is intricately related to the type and density of defects created.
By using a variational Monte Carlo method, we examine an effective low-energy model for LaFeAsO derived from an ab initio downfolding scheme. We show that quantum and many-body fluctuations near the antiferromagnetic (AF) quantum critical point largely reduce the antiferromagnetic ordered moment. Our derived model not only quantitatively reproduces the small ordered moment in LaFeAsO, but also accounts for the diversity from LaFePO, BaFe_2As_2 to FeTe. Electron correlation is found to determine the observed material dependence. We also find that LaFeAsO is subject to large orbital fluctuations, sandwiched by the AF Mott insulator and weakly correlated metals. The orbital fluctuations and Dirac-cone dispersion hold keys for the diverse magnetic properties. (author)
The present conference discusses plasma-assisted surface coating/modification processes, the applications to date of ion nitriding, the effects of nitrogen on metal surfaces, ion nitriding mechanisms in Cr, Al and Cr + Al-containing 1040 steel, ion nitriding of Al and its alloys, life enhancement for forging dies, novel anode plasma nitriding developments, and a comparative study of the pulsed and dc ion-nitriding behavior in specimens with blind holes. Also discussed are the influence of heating method on ion nitriding, surface hardening of marage steels by ion nitriding without core hardness reduction, plasma nitriding of nodular cast iron sput gears, NbN composites for superconductors, the carburization of tungsten in a glow discharge methane plasma, economic considerations concerning plasma nitriding, and the corrosion properties obtained by ion nitriding.
We report significant enhancement in superconducting properties of yttrium substituted Ce1-xYxOFFeAs superconductors. The polycrystalline samples were prepared by two step solid state reaction technique. X-ray diffraction confirmed tetragonal ZrCuSiAs structure with decrease in both a and c lattice parameters on increasing yttrium substitution (with fixed F content). With smaller ion Y in place of Ce, the transition temperature increased by 6 K. Yttrium doping also lead to higher critical fields as well as broader magnetization loops, particularly at elevated temperature.
As a general approach to the problem of precursive behavior in alloys that undergo a displacive transformation, defect theories are becoming increasingly popular. However, the microscopic origin of the proposed defects is usually not considered. Yu and Anderson (1984) have argued that properties of strong-coupling superconductors, such as the A-15 compounds, imply a breakdown of Migdal's theorem (the adiabatic, or Born-Oppenheimer approximation for separation of electrons and phonons) in these systems. The electron-phonon coupling is so strong that it must be incorporated already in zeroth order. This is the basis for local phonon models, in which the electron-phonon coupling provides an effective double well potential for a localized group of atoms. The Yu-Anderson model and an analogous local Jahn-Teller model (Abell, 1983) are reviewed in connection with displacive transformations in strong-coupling alloys.
We investigated the magnet field dependence of the X-ray pulse height and the critical current of a Ti/Au bilayer TES micro-calorimeter. The pulse height was strongly affected by the magnetic field intensity applied perpendicularly to the TES surface. We found that the critical current at zero temperature, I c0, decreased by a factor of two by applying a magnet field of ?10??T. Our data are consistent with a TES sensitivity proportional to (I/I c0)?2/3, as predicted by the Ginzburg-Landau theory. This fact implies that the shape of the R?T curve of the TES is partly determined by the critical current of the superconductor. In order to make our TES microcalorimeters less sensitive to the external magnetic field, we fabricated devices equipped with on-chip magnetic shielding. One device has ...
The Superconducting Super Collider uses approx. =9600 dipole magnets. The magnets have been carefully designed to exhibit minimal magnetic field harmonics. However, because of superconductor magnetization effects, iron saturation and conductor/coil positioning errors, certain harmonic errors are possible and must be corrected by use of multipole correctors called trim coils. For the most efficient use of axial space in the magnet, and lowest possible current, a distributed internal correction coil design is planned. The trim coil assembly is secured to the beam tube, a uhv tube with special strength, size, conductivity and vacuum. The report details the SSC trim coil/beam tube assembly specifications, history, and ongoing development.
To study the nanoscale electronic order in strongly correlated electron systems and vortex states in high-Tc superconductors in high magnetic fields, we have developed scanning tunneling microscopy (STM) for the 18 T cryocooled superconducting magnet (18T-CSM). The test results of the STM operation in the 18T-CSM at room temperature indicate that our STM has a good atomic resolution up to 18 T when we use the nonmagnetic vibration-isolation table which reduce the vibration noise from the cryocoolers of the 18T-CSM. In this paper, we report on the design of the high-field STM system for large-scale magnets and its performance.
The thermal recovery of superconducting elements working as secondaries in fault current limiters can be enhanced by taking advantage of the removal of heat by conduction from an array of artificial weak zones (AWZ) distributed along the superconductor perimeter (hot parts) to the non-weak segments (cold parts). These results were obtained by studying samples with weak parts in the shape of grooves, all identical in size. In this paper we consider the case in which one of the AWZ is slightly different from the rest. Our results show that a change in its length has a negligible effect. On the contrary, a groove which is slightly deeper can be overheated and hence can strongly determine the recovery time of the whole limiter.
From optical point of view and due to the magnetic interaction of the cold neutrons with the unpaired electron shell, magnetic materials hae a neutron spin-dependent refractive index n[sup +] [spin up] and n[sup -] [spin down]. Magnetic media such as Fe, Co and Ni react like birefringent uniaxial crystals in ordinary optica. n[sup +] and n[sup -] are the equivalent of the ordinary and extraordinary refractive indices. The specular reflection of spin polarized neutrons which is due to the discontinuity of the magnetic induction at the surface of the ferromagnet is a sensitive probe of surface and interface magnetism. We shall first give the background of the art of polarized neutron optics. Secondly, some recent examples from surface and interface magnetism will be given to illustrate the power of this technique such as the magnetic coupling in thin films and multilayers and flux penetration in superconductors. (orig.).
Our Andreev reflection measurements (Phys. Rev. Lett. 87 (2001) 137005) along with other experiments have led to a general consensus that MgB{sub 2} is a multiband superconductor with two main superconducting gaps closing at the same T{sub c}. Here we show the behavior of the small gap as a function of the temperature and magnetic field. This gap is isotropic with T{sub c} of the bulk material but with a specific small (crossover) critical magnetic field of about 1 T much lower than the real H{sub c2}. The latter field is anisotropic and is rather governed by the large gap and strongly anisotropic Fermi surface of the material.
We discuss the current state of the art in the IGC Internal Tin Nb_3Sn process which routinely is delivering current densities greater than 1 x 10"3 A/mm"2 at 10 Tesla. We focus especially on the conductors suitability for high current density applications such as High Energy Physics and small magnets. Projections are also made as to its suitability for high field applications such as in Fusion. A discussion of the manufacturing process is given with comparisons made to other accepted Nb_3Sn processes and NbTi. Superconductor characteristics such as filament quality and Nb_3Sn phase uniformity are compared to those obtained in conventional bronze process.
The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS_2 amd NbS_2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the ...
A novel algebraic topology approach to supersymmetry (SUSY) and symmetry breaking in quantum field and quantum gravity theories is presented with a view to developing a wide range of physical applications. These include: controlled nuclear fusion and other nuclear reaction studies in quantum chromodynamics, nonlinear physics at high energy densities, dynamic Jahn-Teller effects, superfluidity, high temperature superconductors, multiple scattering by molecular systems, molecular or atomic paracrystal structures, nanomaterials, ferromagnetism in glassy materials, spin glasses, quantum phase transitions and supergravity. This approach requires a unified conceptual framework that utilizes extended symmetries and quantum groupoid, algebroid and functorial representations of non-Abelian higher dimensional structures pertinent to quantized spacetime topology and state space geometry of quantum operator algebras. Fourier transforms, generalized Fourier-Stieltjes ...
We present a new aspect of superconductivity in A-15 compounds which is able to explain their exceptional role among the high Tc superconductors. The basic idea is that a strong energy dependence of the the electronic density of states near the Fermi level may greatly reduce the repulsive part of the frequency dependent electron-phonon interaction. This leads to a large enhancement of Tc which is a maximum when the Fermi energy is comparable to a typical phonon energy. Our findings are based on numerical solutions of the Eliashberg equations where both the retardation of the electron-phonon coupling and the energy dependence of the electronic density of states have been included. For the electronic density of states we use the models of Labbe and Friedel and of Cohen et al., while the shape of the Eliashberg function #alpha#"2F(#omega#) is taken from the tunneling results of Shen. We compare our theory to experimental results for ternary A-15 compounds. (orig.).
DescriptionThe overall objective of the project is to provide an improved understanding of the processes and linkages through which organic carbon additions influence soil bio-physical and physico-chemical properties. Soil organic carbon (SOC) levels and turnover rates are intimately linked to the soil properties that are important in the maintenance of soil quality and fertility, and sustainable crop production. However, it has been difficult to distinguish the various processes and linkages through which [continued...
...Assemblages of plants and invertebrate animals of tumulus (organic mound) springs of the Swan Coastal Plain Assemblages of plants and invertebrate animals of tumulus ...organic mound) springs of the Swan Coastal Plain [Skip navigation links] About us | Contact us | Publications |...ecological communities Assemblages of plants and invertebrate animals of tumulus (organic mound) springs of the Swan Coastal Plain Advice to the Minister for the ...of the 'Assemblages of plants and invertebrate animals of tumulus (organic mound) springs of the Swan Coastal Plain' community sufficient to distinguish it from ...
The method and results of the quantitative gas chromatographic determination of volatile organic substances in an urban atmosphere are presented. The concentration of organic substances was determined by using a mixed adsorber consisting of graphitized thermal carbon black and activated charcoal modified by pyrocarbon. Average, maximum and minimum concentrations of constant organic components in the atmosphere of Leningrad as a typical large industrial city are reported.
As the Operating and Support staffs of the FFTF organization have gained experience, the plant reliability and capacity factors have shown a steadily improving trend. The plant capacity factor for Cycle 4 was 99.5%. It is the purpose of this report to describe the evolution of the maintenance organization at the FFTF site from a general support organization to a technically proficient organization playing a major role in planning and performance of plant maintenance evolutions.
One of the most challenging topics in the area of organic electronic devices is the growth of transparent electrodes onto flexible polymeric substrates that will be characterized by enhanced conductivity in combination with high optical transparency. An essential aspect for these materials is their synthesis and/or microstructure which define the transparency, the stability and the interfacial chemistry which in turn determine the performance and stability of the organic electronic devices, such as organic light emitting diodes, organic photovoltaics, etc. In this work, we will discuss the latest advances in the growth of organic (e.g. PEDOT:PSS) and inorganic (e.g. zinc oxide-ZnO, indium tin oxide-ITO) conductive materials and their deposition onto flexible polymeric substrates. We will compare the optical, structural, nano-mechanical and nano-topographical properties of the ...
The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi_2B_2C and LuNi_2B_2C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi_2B_2C and LuNi_2B_2C single-crystal samples exhibit large transverse magnetoresistance (#approx#6 8% at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T_c. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between #approx#150 K and RT. Extrapolation to T=0 gives large intercepts (few #mu#V/K) for both samples suggesting the presence of a much larger knee than would be expected from electron-phonon interaction renormalization effects. The upper ...
We present accurate tight-binding parametrizations of the first-principles augmented-plane-wave or linear-augmented-plane-wave band structures of LaCuO_3, La_2CuO_4, Ba_2CuO_4, and the high-temperature superconductor YBa_2Cu_3O_7. We discuss the methodology and efficient application of these fits, including as an example our tight-binding coherent-potential-approximation (CPA) calculations of the effects of disorder on the electronic structure of La/sub 2-//sub x/Ba/sub x/CuO/sub 4-//sub y/. Our CPA calculations support the hypothesis of a rigid-band lowering of the Fermi level for La/sub 2-//sub x/Ba/sub x/CuO_4, enhancing the density of states there. However, for La_2BaCuO/sub 4-//sub y/ they yield the interesting result that oxygen vacancies also lower E/sub F/ and raise N(E/sub F/). This is a significant result for the theory of superconductivity in these materials. In addition to CPA calculations, our parametrizations of the band structures should prove to be ...
Organization factors have been known as an important contributor to plant safety. Previous studies associated with assessing organisation factors mainly deals with the aspect of safety of an organization. For an organization, however, efficiency or an aspect of economy related with work activities is also important. This paper introduces a conceptual model, SPOOM-EDM (Self Poly-Oriented Organizational Model - Evaluation Diamond Model), for evaluating an organization with respect to both safety and economy. It also shows how the proposed model can be applied for the evaluation of an organization through the analysis of real events. (author)
In order to calculate the doses received by the organs of 530 children treated by radiation for cancer between 1945 and 1969 at the G. Roussy Institute, we have developed a computer program for organ location calculation. To calculate the location of each child's organs of interest at the time of the treatment, only two parameters are necessary; sex and height or sex and age when the height at the time of the treatment is unknown. The algorithm is based on the metric studies of growth known as auxology. Each organ is located by one point representing its center. The model has been checked on 100 healthy children.
Development in organic farming has been stimulated by farmers and consumers becoming interested in healthy food products and sustainable environment. Organic agriculture is a holistic production management system which is based on the principles of health, ecology, care, and fairness. Organic development in Uganda has focused more on the crop sector than livestock sector and has primarily involved the private sector, like organic products export companies and non-governmental organizations. Agriculture in Uganda and many African countries is predominantly traditional, less mechanized, and is usually associated with minimum use of chemical fertilizers, pesticides, and drugs. This low external input agriculture also referred to as "organic by default" can create basis for organic farming where agroecological methods are introduced and present ...
Abstract:- This study was undertaken to investigate the antimicrobial effect of organic acids against-Escherichia coli-O157:H7,-Salmonella-Typhimurium, and-Listeria monocytogenes-on whole red organic apples and lettuce. Several studies have been conducted to evaluate organic acids as sanitizers. However, no studies have compared antimicrobial effects of various organic acids on organic fresh produce, including evaluation of color changes of produce. Apples and lettuce were inoculated with a cocktail of 3 strains each of 3 foodborne pathogens provided above and treated with 1% and 2% organic acids (propionic, acetic, lactic, malic, and citric acid) for 0, 0.5, 1, 5, and 10 min. With increasing treatment time and acid concentration, organic acid treatments showed significant reduction compar...
This paper presents the characteristics of selected parameters of organic matter of the Tertiary coal samples and organic matter of Carboniferous rock samples from the Spitsbergen. The coal samples were taken from Central Coal Basin (the Longyearbyen region) and from the Forlandsundet Basin (Oscar II Land, the Kaffioyra region). Samples of dispersed organic matter were collected from Suffolk Pynten and Sergeijevfjellet area in Sorkapp Land. The optical properties of coal samples are different from properties of dispersed organic matter. Macerals of vitrinite group dominate in all of the samples. The average content of vitrinite group macerals is much lower in dipersed organic matter samples than it is in coals. The average content of liptinite group macerals is a little lower, and inertinite group macerals is much higher. The average content of mineral matter is higher in ...
The erosion of rocks rich in organic matter typically leads to the complete mineralization of the organic material. However, in some cases, it is re-deposited to become a part of sediments once more. This process should be considered to be a part of global carbon cycle, possibly much more significant than assumed to-date. The research presented here aims to characterize re-worked organic matter occurring in post-glacial sediments of southern part of Poland, in the Oder river valley (the Racib?rz town region, Miocene, Pleistocene and Holocene age). Organic substances extracted from the sediments originated from organic matter that had resided in rocks eroded by glaciers. Sediments were sampled in two boreholes which sediments were correlated. Sediments were extracted and extracts analyzed w...
...qualified and who were under consideration at the time, USDA Secretary Tom Vilsack chose an animal husbandry specialist employed by one of the largest organic livestock product marketers in the country. While this appointee had grown up on a conventional farm, her immediate occupation is not that of ...
A detailed map of the transcriptional organization of the CELO virus genome was produced. Recent computer analysis of CELO virus has indicated the presence of 38 putative open reading frames (ORFs)....Full Text Available
To study the topographical organization of mu and beta band event-related desynchronization (ERD) associated with voluntary hand and foot movements, we used magnetoencephalographic (MEG) recordings...Full Text Available
The effect of thiamin on the organ distribution of lead was evaluated in CD-1 mice exposed intragastrically or intraperitoneally to a single dose of lead acetate (100 micrograms) containing 100 microCi...Full Text Available
Microbes in nature frequently function as members of complex multitaxon communities, but the structural organization of these communities at the micrometer level is poorly understood because of limitations...Full Text Available
We present experimental evidence for self-organization of nickel microparticles in silicon under certain thermodynamic conditions of nickel diffusion doping. The concentration and distribution of the microparticles in silicon are very uniform. Additional anneals lead to self-ordering of the impurity microparticles.
The subfornical organ is a major receptor area for one of the principal stimuli of thirst, the octapeptide, angiotensin II. In conscious water-sated rats, the authors examined the effects of intravenous infusion of angiotensin II on the rate of glucose utilization in the subfornical organ and in structures anatomically and functionally connected with it. Angiotensin II produced pressor and drinking responses and increased glucose utilization selectively in the subfornical organ and pituitary neural lobe and in no other brain structure. Treatment with the angiotensin II antagonist, sar1-leu8-angiotensin II, before intravenous administration of angiotensin II prevented metabolic stimulation of the subfornical organ and neural lobe. Captopril, an inhibitor of angiotensin-converting enzyme, reduced subfornical organ glucose metabolism to a level similar to that found in control animals. ...
Administrative procedure connecting for licensing new materials or consumer products appropriated to radiosterilization have been performed and explained. Also the organization of irradiation process for attaining the proper result have been described in detail. 4 refs, 1 tab.
Overviews, publications, and new directions are presented for the following research topics: geminate charge pairs in hexane, dipoles in nonpolar and polar organic liquids, organic donor-acceptor interfaces, and charge-transfer states (phenanthrene/PMDA).
I briefly review the process of community organization, education, and advocacy activities that ended the harmful military practices in the island-municipality of Vieques, Puerto Rico, while drawing...Full Text Available
An organ-specific invertase deficiency affecting only the primary root system is described in the Oh 43 inbred maize (Zea mays). Invertases (acid and neutral/soluble and insoluble)...Full Text Available
The acute shortage of human organs and tissues for transplantation has been attributed in part to health professionals, including nurses, for their reluctance to recognize and refer suitable candidates...Full Text Available
Large quantity of reliable protein interaction data are available for model organisms in public depositories (e.g., MINT, DIP, HPRD, INTERACT). Most data correspond to experiments with the proteins...Full Text Available
The OH-initiated photo-oxidation of n-butane was used as a source of 1- and 2-butoxy radicals. Reactions producing ketones and other organic compounds are explained. Rates of photolysis were determined and are discussed.
The corrosion behavior of Ta, Ti, and Zr in inorganic acids, bases, chlorides and miscellaneous salts, waters and gases, and organic acids and miscellaneous organic chemicals is summarized. (W.L.H)
The impact of introducing a 3,6,9-trioxadecyloxyl group at various positions of the desazadesferrithiocin (DADFT) aromatic ring on iron clearance and organ distribution is described. Three DADFT...Full Text Available
Supercoiled double-stranded DNA molecules (plasmids) were isolated from plants infected with three laboratory strains of western aster yellows mycoplasma-like organism (AY-MLO) by using cesium chloride-ethidium...Full Text Available
This book provides differential diagnostic possibilities of specific scan abnormalities in one volume for easy reference. This book is organized by organ systems and covers the central nervous system, the endocrine, skeletal, pulmonary, gastrointestinal, genitourinary, and cardiovascular systems. The gamuts are designed to teach differential diagnosis and to assist in the actual interpretation of patient slides.
Although functional organ stem cells persist in the old, tissue damage invariably overwhelms tissue repair, ultimately causing the demise of an organism. The poor performance of stem cells in an aged...Full Text Available
BackgroundSelenium is a trace element performing important biological functions in many organisms including humans. It usually affects organisms in a strictly dosage-dependent manner...Full Text Available
Abstract This paper focuses on the basic principles of information technology (IT) organization within health sciences centers. The paper considers the placement of the leader of the...Full Text Available
This report describes the work performed during FY 1995 by Pacific Northwest Laboratory in developing and optimizing analysis techniques for identifying organics present in Hanford waste tanks. The main focus was to provide a means for rapidly obtaining the most useful information concerning the organics present in tank waste, with minimal sample handling and with minimal waste generation. One major focus has been to optimize analytical methods for organic speciation. Select methods, such as atmospheric pressure chemical ionization mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry, were developed to increase the speciation capabilities, while minimizing sample handling. A capillary electrophoresis method was developed to improve separation capabilities while minimizing additional waste generation. In addition, considerable emphasis has been placed on developing a rapid screening tool, based ...
In the past decade in vitro tests have been developed that represent a range of anatomic structure from perfused whole organs to subcellular fractions. To assess the use of in vitro tests for toxicity...Full Text Available
DescriptionChamber studies have shown that biogenic organic compounds, including isoprene, are capable of producing secondary organic aerosol in significant quantities. This is surprising as isoprene and its photo-oxidation products have relatively high vapour pressures. However, it is very important as isoprene has the largest global emissions flux of any biogenic hydrocarbon, most of which is in the tropics. Despite this, secondary organic aerosol has been poorly studied in tropical regions with only [continued...
... counseling, some training, and assure the general health and welfare of the command. ... publications, promotions, OERs/NCOER's (Officer Efficiency ...
This forum showcases the work of a variety of different heritage-based centers, organizations, and projects dedicated to research, education, and preservation of tangible and intangible forms of cultural heritage. The descriptions of these centers demonstrate the diversity of heritage work being done today. The centers and projects described in the forum vary in their contexts, missions, and outcomes. Highlighted in the forum are preservation organizations, university-based heritage centers, and a global collaborative cultural heritage project. Each organization in the forum provides information about their missions and goals, their approaches or methods to heritage work, and a brief description of some of their initiatives.
The partial project SR 2039/4 investigates organizational demands and factors of the man-organization interface. Thee study is divided into the sections inventory of rules and guidelines; evaluation of organizational structures and modes of operation, and working out of demand characteristics and evaluation criteria. The objective consists in representing, analyzing and evaluating the efficiency structure of sequence organization, and deriving practice-relevant concept proposals in order to optimize the man-organization interface. In this regard, the working out of control mechanisms for the evaluation of organizational sequences is of considerable importance as a kind of working aid. (orig./DG).
The purpose of this document is to describe the NIF Project Organization and the roles and responsibilities of the managers charged with executing the Project.
The investigation of the petroleum contamination in marine organisms requires the trace level quantitative determination of indicative substances to be identified by a fingerprint of petroleum. Polymethylnaphthalene (PMN) and polymethylphenanthrene (PMP) were chosen because of their simple separation from a crude oil by means of an activated charcoal chromatography, their relatively high existence in aromatic compounds, and their persistence relative to other petroleum components in the tissue of oil contaminated marine organisms. The purpose of this paper is to present an activated charcoal chromatographic separation procedure of PMN and PMP in a crude oil and a trace level quantitative analytical method of them in marine organisms by mass fragmentography (MF).
The carbon cycle is an important part of major biogeochemical cycles. Many techniques may be used to characterize carbon amounts and sources in the environment. Here we first review the most popular techniques for the determination of organic and inorganic carbon concentrations. Decarbonatation techniques are also reviewed in details since it is often an important part of organic carbon analysis. The second part of this paper addresses the use of carbon stable isotopes to characterize organic carbon sources and processes in the environment. An overview of general stable isotopes background and terminology is given as well as the most popular analytical techniques.
The concentrates of scattered organic matter???kerogen-like polymer, which is insoluble in acids and organic solvents???were isolated from rock samples taken at different depths from various stratigraphic units at the productive deposits of the Orenburg oil-gas condensate field using chemical methods. The chemical composition of the kerogen-like polymer and the concentrations of trace elements in it were studied. The regularities of evolutionary changes in the composition of the organic matter and the concentrations of trace elements in it in the order of the kerogen-like polymer and the following its consecutive derivatives were established: asphaltenes, ethanol-benzene tars, benzene tars, oils, and paraffins
DescriptionThis cross-disciplinary project will combine chemical, ecological and modelling techniques to determine whether cabbages grown under an organic regime differ in terms of pest dynamics and plant chemistry. There is increasing pressure to de-intensify agricultural practice and organic approaches are becoming more popular and widely adopted. However, there are very few, if any, detailed scientific investigations into the claims made about improved pest control, reduced environmental impact and be [continued...
Zr-Al metallo-organic compounds were thermally decomposed to prepare ZrO_2-Al_2O_3 composite powders. The specific surface area was dependent on the organofunctional groups of the starting organic compounds. The pore size distribution was dependent on the heating rate when the heating temperature was the same. 4 refs.; 4 figs.
When an animal is exposed to a sufficient amount of radiation, there will be changes in many organs of the body, and as a result of either the effects in one particular organ or the interaction of effects in several organs, the animal as a whole will show...
The use of filters of activated-charcoal particles in drinking-water purification plants assists in the elimination of organic micropollutant substances. The authors report on a study which sought to investigate the mechanism of organic matter; they describe the experimental programme, which used different size ranges of mineral-based activated charcoal, present the experimental findings and discuss the results. 16 references.
X-ray scattering methods suitable for the investigation of the morphology and chemical composition of self-organized quantum dots and quantum wires are reviewed. Their application is demonstrated in experimental examples showing that a combination of small angle X-ray scattering with high-resolution X-ray diffraction can reveal both the shape and the chemical composition of the self-organized objects. (author)
Loss of organic matter is one of the main forms of soil degradation in Mediterranean agricultural soils, and external sources of organic matter are required to improve soil properties. the two-phase centrifugation system in the olive-oil extraction industry produces a large amount of olive mill waste sludge (TPOMW) which can be used to add organic C to degraded soils. (Author)
Papers presented at a meeting on indoor and outdoor climates on sites polluted with volatile organic chemicals. The papers deal with the subject of evaporation of organic chemicals on the polluted sites in relation to the influence on indoor and outdoor climates. Themes dealt with are diffusion through soils and transport of pollutants from the soil into buildings. (AB).
Fe and Zn were determined in various parts of maize (Zea mays) in dependence on quantity of organic substrate EKOFERT as organic fertilizer in soil, using radionuclide X-ray fluorescence analysis. The increase of quantity of organic substrate EKOFERT in soil causes a decrease of heavy metal concentrations in certain parts of the plant. (author). 4 refs., 1 tab.
The metabolism of organic matter in the coastal regions of the ocean may significantly affect the oceanic carbon budget. This paper describes the high percentage (30%) of oceanic oxidation that occurs in coastal areas and the impact of this metabolism on the carbon cycle and climate of earth. Organic metabolism in the ocean appears to be a source of carbon dioxide release into the atmosphere. Oxidation in the coastal zone is of special interest, as it is likely influenced by anthropogenic activity. Recommendations for future research on this topic are proposed. 129 refs., 2 figs., 6 tabs.
DescriptionThe objective of this project is to relate the processing quality of wheat to the composition of the developing and mature grain using material grown under a range of nutrient regimes including long term organic and fertilised systems from the Rothamsted Broadbalk experiment, variety trials and organically grown wheat. Preliminary studies have indicated substantial differences in the transcriptome profiles of wheat grown with artificial fertiliser and with organic fertiliser on Broadbalk and tru [continued...
The Advances in Library Administration and Organization Series provides a body of research literature that contributes to the base of organizational theory upon which library administrators rely. Its mix of contributions to the literature of library administration and organization is both diverse and eclectic. This volume of the series covers a variety of topics relating to the management of academic, public and school libraries
High-spatial-resolution microfocus-based X-ray imaging technology, both real-time and film, has been used to study the thickness variation that occurs in the oxide core of silver-sheathed BSCCO ribbons produced by the powder-in-tube method. This thickness variation (also called ``sausaging``) occurs during incremental rolling and degrades the critical current densities of the ribbons. Using X-ray image data the authors determined the onset and severity of sausaging. Onset occurred at a ribbon thickness of 203 {micro}m, and the severity increased with subsequent rolling reductions. Scanning electron microscopy was used to confirm the X-ray image data. X-ray imaging provides several advantages over more traditional methods for characterizing the superconductors such as optical or scanning electron microscopy. The X-ray imaging provides nondestructive information about the entire width of the ribbon, with far greater speed, lower cost, and more flexibility than the ...
The T/sub c/ behavior of vapor-deposited Nb_3Ge and Nb_3Sn is examined as a function of low-fluence alpha-particle irradiation. It is found that for Nb_3Sn with rho_0approx.15 #mu##OMEGA#-cm the T/sub c/ is insensitive to low doses of radiation, whereas Nb_3Ge with rho_0approx.50 #mu##OMEGA#-cm has its T/sub c/ depressed immediately with irradiation. It is suggested that the T/sub c/ behavior of A-15 superconductors in the regime of small dose is strongly influenced by the initial state of the sample. Furthermore, it is argued that the behavior of the T/sub c/ with dose can be qualitatively explained by considering a sharp structure in the density of states N(E), the smearing of which by defects leads to a depression in T/sub c/.
The aim of this thesis is to study the coherent transport in semiconducting-superconducting junctions. The SnPb-GaAs system has been studied. It has been shown that the behaviour of this junction is controlled by the disordered area induced by the annealing of the connection near the interface. For a few resistant junction, a conductance anomaly under the gap has been observed and has been explained by a mesoscopic effect in the limit of the very high disorders. The conductance of more resistant junctions has only been bound to the properties of the very disordered area of the semiconductor. The part of the electron-electron interactions on the phase coherence length and on the conductance has been studied. The evolving of the correction of the conductance due to interactions in magnetic field has been followed. The effect of the spin degeneration suppression in CdTe and the GaAs sign inversion in Shubnikov de Haas oscillations rate has been observed. At last has been studied the ...
The structural and electronic properties of the A-15 compounds Nb{sub 3}Rh and Nb{sub 3}Ir were studied by means of escalar relativistic full-potential linearized augmented-plane wave (FP-LAPW) calculations with generalized gradient corrections. An investigation of the band structure of the hypothetical Nb{sub 3}Nb compound was also performed at the theoretical equilibrium lattice constant to ascertain the contribution of the nontransition elements on the B site in these A{sub 3}B-type compounds. Band structures and total densities of states were obtained. A rough estimate of the electron-phonon coupling parameter {lambda} as well as of the electronic specific-heat coefficient {gamma} were obtained for both Nb{sub 3}Rh and Nb{sub 3}Nb, which confirms that this latter is a low-temperature superconductor with T{sub c} - 10K.
We provide a numerically efficient procedure to perform LDA+Hubbard I calculations including self-consistency over the charge density in the FP-LAPW basis. The method is applied to Pu, Am, and PuAm and PuCe alloys. Our results for valence photoemission spectra (PES) agree with experimental data and with previous LDA+DMFT calculations. Analysis of the J=5/2 and J=7/2 contributions to the f-occupation supports the intermediate-coupling picture of f-states in heavy actinides. The electronic specific heat coefficient is calculated for PuAm and PuCe alloys in reasonable agreement with recent experiments. We show that Pu atoms keep their mixed-valence character in these alloys. Next, we study electronic and spectral properties of Pu-based superconductor PuCoGa_5 and obtain good agreement with experimental PES. Finally, we analyze surface effects. In Pu monolayer, we find substantial modification of PES due to 5f-electron localization consistent with experimental ...
We discuss recent results obtained for the heavy-fermion metals UPd{sub 2}Al{sub 3} and YbRh{sub 2}Si{sub 2}. UPd{sub 2}Al{sub 3} is the first among all superconductors for which tunneling and inelastic neutron-scattering data highlight a non-phononic, i.e., magnetic-exciton mediated, pair state. YbRh{sub 2}Si{sub 2} represents a model system exhibiting pronounced non-Fermi liquid effects above a weak antiferromagnetic phase transition at T{sub N}=70 mK. Upon approaching the quantum critical point (T{sub N}{yields}0), by low doping with Ge, one observes for T<0.3 K disparate behavior in the temperature dependences of both the electrical resistivity and the electronic specific heat as well as a Curie-Weiss law in the uniform magnetic susceptibility, implying uncompensated large 4f moments. These observations indicate a break up of the composite quasiparticles into their local f-spin and itinerant conduction-electron parts.
A dipole magnet based on the common coil design, using prereacted Nb{sub 3}Sn superconductor, is under development at Fermilab, for a future Very Large Hadron Collider. This magnet has some innovative design and technological features such as single layer coils, a 22 mm wide 60-strand Rutherford type cable and stainless steel collars reinforced by horizontal bridges inserted between coil blocks. Both left and right coils are wound simultaneously into the collar structure and then impregnated with epoxy. In order to optimize the design and fabrication techniques an R&D program is underway. The production of cables with the required characteristics was shown possible. Collar laminations were produced, assembled and tested in order to check the effectiveness of the bridges and the validity of the mechanical design. A mechanical model consisting of a 165 mm long section of the magnet straight section was assembled and tested. This paper summarizes the status of ...
The main LHC superconducting magnets (dipoles and quadrupoles) use Rutherford type cables, stabilized electrically and thermally with copper profiles. The portions of cables are connected to each other by a soft soldering technique (Sn96Ag4) with an overlapping length corresponding to one pitch of the superconducting strands. The splice constitutes a "composite" structure with the interchanging layers of Sn96Ag4 and NbTi superconductor, located inside a Cu cage. In order to ensure a high level of reliability (failure probability not exceeding 10-8) for some 10000 connections in the LHC, a non-destructive technique to check the quantity of solder in the joint is foreseen. The technique is based on a gamma ray source (241Am) and the detection is position-sensitive in the transmission mode. Scintillating detectors of gamma rays are used and their accumulated length corresponds to the length of the radioactive source (120 mm). The method can be used in-situ, the ...
Results of our systematic NMR study in high T_c cuprates are reviewed. The antiferromagnetic spin fluctuations (AFSF) decrease in the order of La_1_._8_5Sr_0_._1_5CuO_4. YBa_2Cu_3O_7 and Tl_2Ba_2CuO_6_+_y. 1/T_1 of "6"3Cu in the CuO_2 plane in the normal state follows essentially a Curie-Weiss law at high temperature and T_1T = const. law at low temperature. The temperature dependence of 1/T_1 and the Knight shift together with their impurity effect in the superconducting state strongly suggest d-wave pairing implying the AFSF to be responsible for the occurrence of superconductivity. From the NQR frequency measurement the density of Cu 3d and O 2p holes decreases and increases, respectively, in the order of La, Y and Tl compounds, which is consistent with the change of AFSF. The relation between T_c and #nu#_Q, and their pressure dependence suggest that there exists and optimum value of the ratio of Cu 3d and O 2p hole density to give a maximum in T_c. (orig.).
The LHC magnet tests operation team developed various innovative techniques, particularly since early 2004, to complete the superconductor magnet tests by Feb. 2007. Overall and cryogenic priority handling, rapid on-bench thermal cycling, rule-based goodness evaluation on round-the-clock basis, multiple, mashed web systems are some of these techniques applied with rigour for successful tests completion in time. This paper highlights these operation empowerment tools which had a pivotal role for success. A priority handling method was put in place to enable maximum throughput from twelve test benches, having many different constraints. For the cryogenics infrastructure, it implied judicious allocation of limited resources to the benches. Rapid On-Bench Thermal Cycle was a key strategy to accelerate magnets tests throughput, saving time and simplifying logistics. First level magnet appraisal was developed for 24 hr decision making so as to prepare a magnet further ...
The resonance line shift of a series of A-15 structures (V_3Pt, Vsub(0.76)Ptsub(0.24) and Vsub(0.62)Irsub(0.38) is measured as a function of temperature in the superconducting state. A method will be described to separate the contribution of the diamagnetism of the superconductor (Meissner effect) and that of the Knight shift to this line shift. From the temperature dependence of the Knight shift of the V atoms the sum of the s and d contribution to the Knight shift can be determined. In these three compounds the s and d contributions appear to cancel out nearly. Moreover the temperature dependence of kappa_2 can be calculated from the measurements. The values of kappa_2 extrapolated at T=Tsub(c) are about 70 for these samples. From the obtained sum of Ksub(s) and Ksub(d) and the data of the susceptibility or of the specific heat of these samples Ksub(s) and Ksub(d) can be separated. For all samples Ksub(s)=0.06+-0.005%. Finally it was observed that the quadrupolar ...
Brittleness and poor low-temperature thermal conductivity of A-15 compounds remain the major obstacles preventing the effective use of these superconductors in large-scale engineering applications. In order to circumvent these difficulties, a new type of ductile superconducting filamentary alloy has been developed recently by a simple metallurgical process which consists of melting the constituent elements and subsequent cold working and appropriate heat treatment. These superconducting materials are essentially Cu-base alloys containing a few percent of A-15 phase such as Nb_3Sn or V_3Ga which is in the form of fine filaments embedded in the Cu matrix. The emphasis of this work is on the formation of the A-15 phase in the Cu-base alloys and its correlation with superconducting properties such as transition temperature and critical current density. The formation of Nb_3Sn, Nb_3Al, V_3Si, and V_3Ga will serve as examples to illustrate the importance of some features ...
The relationship between processing, microstructure, and properties was studied for A-15 compounds in multifilamentary composites produced by solid-state diffusion and in thin-film samples produced by vapor deposition. Grain sizes of A-15 superconducting compounds were measured by transmission electron microscopy of multifilamentary composites reacted at various temperatures. Critical current densities at 4.2 K and fields up to 6 T were found to be similar for niobium-tin, vanadium-gallium, and vanadium-silicon of the same grain size. Study of the Cu-V-Si phase diagram led to the production of improved multifilamentary vanadium-silicon conductors. The effects of various alloying elements on A-15 layers produced by solid-state diffusion were studied. The most promising new observation was that tantalum can be incorporated into niobium-tin reaction layers, leading to an enhancement of critical currents at high fields. The critical temperature of vapor-deposited, niobium-germanium films ...
Fault current limiters (FCLs) are devices for to suppress current in electric power system. The FCL is extensively expected to suppress fault current, particularly required for trunk power systems heavily connected high-voltage transmission lines, such as 500 kV class power system. For this reason, FCLs based on various principles of operation have been developed. Most of the FCLs under development which employ superconductors are based on the quenching phenomenon peculiar to the superconducting state, that is, making use of a rapid transition to normal conducting state, an electrical resistance appears, and this resistance is used to suppress fault currents. However, this elevation of resistance, although increasing the fault current suppression effect, also tend to raise the overvoltage occurring FCL, the ascertainment of the overvoltage is important as regards the protection of the FCL as well as other power system devices. Hence the waveform created in the FCL ...
The electronic structure and surface interactions vapor-deposited Cu on single-crystal and polycrystalline Bi_2Ca/sub 1+//sub x//sub Sr>2-//sub x//sub Cu>2/O/sub 8+//sub y/ were studied using x-ray photoelectron spectroscopy. The results are compared to the Cu/YBa_2Cu_3O/sub 7-//sub x/ interface. Changes in the Cu 2p satellite emission indicate that the Cu adatoms do not disrupt Bi_2Ca/sub 1+//sub x/Sr/sub 2-//sub x/Cu_2O/sub 8+//sub y/ as extensively as YBa_2Cu_3O/sub 7-//sub x/. However, deposition of Cu induces changes in the Bi environment in the superconductor, and surface segregation of Bi metal was observed at high coverages. Core-level attenuation results suggests minimal outdiffusion of oxygen, in contrast with what is observed for Cu/YBa_2Cu_3O/sub 7-//sub x/.
Theoretical work supported by this grant has lead to the concept of the specific pinning force Q and the development of new methods to sum elementary interaction forces to find Q. Pinning due to changes in transition temperature or thermodynamic critical field in thin layers (e.g., a grain boundary), is greatly reduced due to the proximity effect and the stress field interaction due to the dislocations in the grain boundary has been shown to be negligible. The crystalline anisotropy (CA) and electron scattering (ES) interactions have been computed for the first time for an arbitrary boundary. Experiments on niobium bicrystals, polycrystalline niobium thin foils doped with oxygen, lead-bismuth alloy thin films and lead-bismuth alloy films in which either lead or thallium has been allowed to diffuse down the grain boundaries and out into the grains provide evidence that confirms the predictions of the theory. These results suggest that further improvements in grain boundary pinning in ...
We present results of electronic structure calculations for the intermetallic perovskite Sc3InB with the full-potential KKR-LDA method. Sc3InB is a very promising candidate for a new superconductor (related to 8 K MgCNi3) and can be regarded as a boron-inserted cubic Sc3In, which is a high-pressure allotropic form of the hexagonal weak ferromagnet Sc3In. We predict that cubic Sc3In can also be magnetic, whereas Sc3InB having large DOS in the vicinity of E F exhibits non-magnetic ground state. Estimation of the electron-phonon coupling for Sc3InB gives 1. Furthermore, the effect of vacancies in Sc3InB1-x and antisite disorder in Sc3(In-B) on critical parameters is also discussed using the KKR-CPA method. All theoretical results support the possibility of the superconductivity onset in Sc3InB. Preliminary experimental measurements established the transition temperature close to 4.5 K, with a very abrupt change in susceptibility and a correlated drop of the ...
A comparative study on the critical current performance of Bi-2223/Ag and YBCO coated conductor wires in low magnetic fields at liquid nitrogen temperature was carried out in this work. Five commercial high temperature superconductor wires from different manufacturers were collected. Their critical currents were measured in magnetic fields, ranging from 0 to 0.4 T. On contrary to the common conception, the Bi-2223/Ag samples had better performance than YBCO coated conductor samples in the magnetic fields parallel to the wide surface of superconducting wires within the experimental scope. We also found similar results by collecting the concerned datum from the published literatures to confirm our measurement results. At the present stage, this fact made that the Bi-2223/Ag wires might be the preferred choice for the applications with mainly low parallel fields involved, unless other considerations were prioritized.
Low transition temperature (low-{Tc}) and high-{Tc} Superconducting QUantum Interference Devices (SQUIDs) have been used to perform high-resolution magnetic measurements on samples whose temperatures are much higher than the operating temperatures of the devices. Part 1 of this work focuses on measurements of the rigidity of flux vortices in high-{Tc} superconductors using two low-{Tc} SQUIDs, one on either side of a thermally-insulated sample. The correlation between the signals of the SQUIDs is a direct measure of the extent of correlation between the movements of opposite ends of vortices. These measurements were conducted under the previously-unexplored experimental conditions of nominally-zero applied magnetic field, such that vortex-vortex interactions were unimportant, and with zero external current. At specific temperatures, the authors observed highly-correlated noise sources, suggesting that the vortices moved as rigid rods. At other temperatures, the ...
Model construction of the laboratory scale superconducting fault current limiter circuit (SFCL) has been performed. The SFCL is fault current limiter and used as electric network security. It mainly consists of a copper coil, a superconducting ring and an iron core that are concentrically arranged. The SFCL circuit is essentially a transformer where the secondary windings are being replaced by the ring of YBa_2Cu_3O_7_-_x superconductor (HTS). The ring has critical transition temperature Tc = 92 K and critical current Ic = 3.61 A. Characterization of the SFCL circuit is simulated by ANSYS version 5.4 software. The SFCL circuit consists of load and transformer impedances. The results show that the inductions of magnet field flux in the iron core of primer windings and ring disappear to one other before fault state. It means that impedance of the transformer is zero. After the condition a superconductivity behavior of the ring is disappear so that the impedance of ...
This report summarizes the work on high field superconducting materials and processes performed at the Materials and Molecular Research Division of the Lawrence Berkeley Laboratory. Two major interrelated focal points characterize this research. One was the decision to restrict the effort to A-15 compounds because of their superior critical temperatures and critical fields. The inherent brittleness of these compounds along with the requirement for a filamentary morphology led to the second focal point: a heavy reliance on a powder approach for the fabrication of superconducting tapes and wires. There have been exceptions to the use of powder techniques where special circumstances such as the nature of a particular alloy system suggested on alternative approach. The quench-age technique described herein is an example of a non-powder approach. Here the niobium-aluminum system is involved and the methodology is based on the fact that in a certain composition range a solid solution of ...
The grain boundary misorientation distribution of 203 grain boundaries in bulk processed high Tc superconductor YBa_2Cu_3O_7_-_#delta# with five processing conditions;, was studied. Two complementary analytical approaches, Grain Boundary Misorientation Distribution (GBMD) from the random description, using a hypothesis test and #chi#"2 analysis, and Grain Boundary Character Distribution (GBCD), using the Coincidence Site Lattice (CSL) model, were applied. The GBMD and GBCD both showed grain boundary evolution departing from a random distribution above 935 C processing temperature. The GBCD analyses indicated an approximately linear increase in the population of CSL-related boundaries, among which the tetragonal CSL (c/a #not =# 3) boundaries grew in the same trend while orthorhombic boundaries (c/a = 3) became stagnated. The results from comparing the corresponding GBCD and volume averaged J_c for each batch indicated that the tetragonal CSL boundaries were oxygen ...
Specific objectives were to: (1) develop and refine a methodology that can be used to evaluate the feasibility of MAG-LEV trains; (2) apply this methodology to the state of Oklahoma. The methodology is based on an aggregate econometric demand model and mathematical programming. A city-pair network is constructed to evaluate alternative MAG-LEV routes between Oklahoma City and nine other cites in and out of the state of Oklahoma. Results obtained from the aggregate econometric demand model indicates that MAG-LEV trains would attract significant ridership along different types of origin-destination routes. All nine corridors exhibit induced demand for MAG-LEV trains as well as attracting riderships from other modes. Based on the results of both single and multiobjective LP models, fixed-capital-cost requirements and annual operating cost for each of the above corridors are estimated, and by using different scenarios for discount rates, both costs and revenue were converted to annual ...
Tests have recently been performed at Fermilab in order to measure the energy losses due to eddy currents and iron and superconductor magnetization. These measurements were performed on six 1.5m long model magnets and eight 15m long full scale collider dipole magnets. AC losses were measured as a function of ramp rate using sawtooth ramps from 500, to 5000 Amps for both types of magnets, while bipolar studies were additionally performed on some of the short magnets. The measured magnet voltage and current for a complete cycle are digitally integrated to yield the energy loss per cycle. Measurement reproducibility is typically 5%, with good agreement between long magnet measurements and extrapolations from short magnet measurement results. Magnetization loss measurements among similar magnet types agree to within experimental error, while eddy current losses correlate strongly with the observed dependence of quench current on ramp rate.
The A-15 compounds are known to favor the occurrence of high temperature superconductivity (transition temperature T/sub c/ > 15K). The origin of superconductivity in these metals is a subject of much controversy and importance. A useful approach to this problem is to study comparatively the superconducting and normal-state properties of the A-15 superconductors and their amorphous counterparts. Efforts along these lines have yielded some insight into the mechanisms responsible for high temperature superconductivity. It is interesting to note that most high-T/sub c/ A-15 compounds contain one glass-forming element such as Ge, Si or Al and are thus conducive to the formation of a non-crystalline phase. The amorphous (or higher disordered) state of the A-15 compounds can be achieved, for example, by one of the following techniques: (1) sputtering or co-evaporation onto substrates held at relatively low temperatures; (2) particle irradiation; and (3) ion-mixing. It ...
This paper contains literature from American Power Conference Air Toxics Being Measured Accurately, Controlled Effectively NO{sub x} and SO{sub 2} Emissions Reduced; Surface Condensers Improve Heat Rate; Usable Fuel from Municipal Solid Waste; Cofiring Technology Reduces Gas Turbine Emissions; Trainable, Rugged Microsensor Identifies of Gases; High-Tc Superconductors Fabricated; High-Temperature Superconducting Current Leads; Vitrification of Low-Level Radioactive and Mixed Wastes; Characterization, Demolition, and Disposal of Contaminated Structures; On-Line Plant Diagnostics and Management; Sulfide Ceramic Materials for Improved Batteries; Flywheel Provides Efficient Energy Storage; Battery Systems for Electric Vehicles; Polymer-Electrolyte Fuel Cells for Transportation; Solid-Oxide Fuel Cells for Transportation; Surface Acoustic Wave Sensor Monitors Emissions in Real-Time; Advance Alternative-Fueled Automotive Technologies; Thermal & Mechanical Process; ...
The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C single-crystal samples exhibit large transverse magnetoresistance ({approx}6{endash}8{percent} at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T{sub c}. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between {approx}150 K and RT. Extrapolation to T=0 gives large intercepts (few {mu}V/K) for both samples suggesting the presence of a much larger {open_quotes}knee{close_quotes} than ...
Low-temperature specific-heat measurements have been carried out between 0.5 and 30--50 K on the high-T/sub c/ copper oxide superconductors La/sub 1.8/Sr/sub 0.2/CuO/sub 4-//sub delta/ and RBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ (R = Y, Eu, Ho, Tm, and Yb). The specific heat of the La/sub 1.8/Sr/sub 0.2/CuO/sub 4-//sub delta/ and YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ compounds below T/sub c/ can be resolved into a contribution of the form C/sub e/(T) = ..gamma..'T with a finite ..gamma..' and a lattice contribution that consists of Debye and Einstein terms. Specific-heat data for the RBa/sub 3/Cu/sub 3/O/sub 7-//sub delta/ compounds with R = Ho, Tm, and Yb exhibit no features due to magnetic order above 0.5 K, but reveal electronic Schottky anomalies associated with crystalline electric field (CEF) splitting of the Hund's-rules ground-state multiplet of the R/sup 3+/ ions. The Schottky anomalies can be described by calculations based on ...
Large quantities of organic chemicals used in reprocessing spent nuclear-fuels at the Hanford Site have accumulated in underground high-level radioactive waste tanks. The organic content of these tanks must he known so that the potential for hazardous reactions between organic components and sodium nitrate/nitrite salts in the waste can he evaluated. The solubilities of organic compounds described in this report will help determine if they are present in the solid phases (salt cake and sludges) as well as the liquid phase (interstitial liquor/supernate) in the tanks. The solubilities of five significant sodium salts of carboxylic acids and aminocarboxylic acids [sodium oxalate, formate, citrate, nitrilotriacetate (NTA) and ethylendiaminetetraacetate (EDTA)] were measured in a simulated supernate solution at 25 degrees C, 30 degrees C, 40 degrees C, and 50 degrees C.
Mechanistic studies on a charged ultrafiltration (UF) membrane fouled with natural organic matter (NOM) and colloidal particles are systematically investigated to understand the relative role of each NOM fraction and the presence of colloidal particulate to membrane fouling. Humic acid (HA), dextran, and kaolin were employed as surrogate model foulants representing the organic hydrophobic acid NOM, hydrophilic neutral NOM, and inorganic colloidal materials, respectively. The results obtained showed that the organic NOM of hydrophilic surrogate (dextran) plays a primary role in promoting membrane fouling, followed by hydrophobic acids and inorganic kaolin, but to a lesser extent than organic NOM compounds. Significant differences in the extent of fouling between dextran and HA have been obs...
Recovery of soil organic matter, organic matter turnover and mineral nutrient cycling is critical to the success of rehabilitation schemes following major ecosystem disturbance. We investigated successional changes in soil nutrient contents, microbial biomass and activity, C utilisation efficiency and N cycling dynamics in a chronosequence of seven ages (between 0 and 26 years old) of jarrah (Eucalyptus marginata) forest rehabilitation that had been previously mined for bauxite. Recovery was assessed by comparison of rehabilitation soils to non-mined jarrah forest references sites. Mining operations resulted in significant losses of soil total C and N, microbial biomass C and microbial quotients. Organic matter quantity recovered within the rehabilitation chronosequence soils to a level co...
We present a detailed analysis of the self-organization phenomenon in which the stylized facts originate from finite size effects with respect to the number of agents considered and disappear in the limit of an infinite population. By introducing the possibility that agents can enter or leave the market depending on the behavior of the price, it is possible to show that the system self-organizes in a regime with a finite number of agents which corresponds to the stylized facts. The mechanism to enter or leave the market is based on the idea that a too stable market is unappealing for traders while the presence of price movements attracts agents to enter and speculate on the market. We show that this mechanism is also compatible with the idea that agents are scared by a noisy and risky market at shorter time scales. We also show that the mechanism for self-organization is robust with respect to variations of the exit/entry ...
Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HL) in benzene, toluene, chloroform and tetrachloromethane from aqueous-alcoholic solutions of the formal acidity of 2M-HClO_4 was studied. Methyl, ethyl, n- and isopropyl, tert-butyl and allyl alcohol as well as ethylene glycol monomethyl ether and propylene glycol were used as organic components of the mixed aqueous-organic phase. Their presence in some cases resulted in a synergic increase in the distribution ratio of hafnium. The increase is interpreted using the results of a slope analysis and measurements of the alcohol distribution and the relative permittivity of the organic phase. It is suggested that HfL_4 molecules were solvated by alcohol molecules in the organic phase. At high alcohol concentration synergism changed into antagonism. This was caused by changes in the distribution of HL and its interaction with the alcohol in ...
This paper summarizes studies on the water treatment by adsorption, as for the adsorption during water treatment, reactivation of activated charcoal, and clarification of heating process. Reactivation of activated charcoal for the water treatment is carried out through drying in the heating furnace. Basic problems are the recovery degree of adsorption performance of reactivated activated charcoal and the recovery yield. Behavior of the activated charcoal in the heating reactivation furnace is divided into three stages including drying process, heating process, and gasification process. Among these processes, behaviors of organic matters during heating process are described. Thermogravimetric analyses (TGA) were conducted for activated charcoals adsorbing various organic matters in aqueous solutions. Three types of organic matters were classified from the TGA pattern, i.e., organic matters with ...
Red mud is a waste product of the aluminium refining industry. It is composed of aluminium hydroxide and iron oxide. This study examined the feasibility of using red mud as a catalyst to eliminate volatile organic compounds in atmospheric pollutants. Volatile organic compounds can be eliminated by thermal oxidation between 600 and 1100 degrees C. However, the oxidation of volatile organic compounds can also be accomplished at lower temperatures (200 to 450 degrees C) if a catalyst is present. Currently, the low temperature destruction of volatile organic compounds is not widespread because of the difficulty in deactivating the catalyst. In this study, red mud was calcined in air at 500 degrees C. Under such conditions, the red mud converts to aluminium oxide and iron oxide. These 2 oxides are active and are carbon dioxide selective in the oxidation of volatile organic compounds. The ...
Organic farming (or ecological agriculture) is of growing importance in the agricultural sector worldwide. In the Nordic countries, 1-10% of the arable land was in organic production in 1999. Organic farming can be seen as an approach to agriculture where the aim is to create integrated, humane, environmentally and economically sustainable agricultural production systems. Principles like nutrient recycling, prevention rather than treatment and the precautionary principle are included in aims and standards. Animal welfare is another hallmark of organic livestock production but despite this, several studies have indicated severe health problems e.g. in organic poultry production in Denmark. Also the quality of animal food products in relation to human health, particularly the risk of zoonotic infections, has been debated. For these reasons there is a need for improvement of production ...
We demonstrate tuning of Schottky energy barriers in organic electronic devices by utilizing chemically tailored electrodes. The Schottky energy barrier of Ag on poly[2-methoxy], 5-(2{prime}-ethyl-hexyloxy)- 1,4-phenylene was tuned over a range of more than 1 eV by using self-assembled monolayers (SAM{close_quote}s) to attach oriented dipole layers to the Ag prior to device fabrication. Kelvin probe measurements were used to determine the effect of the SAM{close_quote}s on the Ag surface potential. {ital Ab} {ital initio} Hartree-Fock calculations of the molecular dipole moments successfully describe the surface potential changes. The chemically tailored electrodes were then incorporated in organic diode structures and changes in the metal/organic Schottky energy barriers were measured using an electroabsorption technique. These results demonstrate the use of self-assembled monolayers to control ...
Distinguishing between effects of natural and anthropogenic environmental factors on ecosystems is a fundamental problem in environmental science. In river systems the longitudinal gradient of environmental factors is one of the most relevant sources of dissimilarity between communities that could be confounded with anthropogenic disturbances. To test the hypothesis that in macroinvertebrate communities the distribution of species' sensitivity to organic toxicants is independent of natural longitudinal factors, but depends on contamination with organic toxicants, we analysed the relationship between community sensitivity SPEARorganic (average community sensitivity to organic toxicants) and natural and anthropogenic environmental factors in a large-scale river system, from alpine streams to a lowland river. The results show that SPEARorganic is largely independent of natural longitudinal factors, but strongly dependent on ...
Several short-lived, high-energy beta emitters are being proposed as the radionuclide components for molecular-targeted potential cancer therapeutic agents. The laboratory mice used to determine the efficacy of these new agents have organs that are relatively small compared to the ranges of these high-energy particles. The dosimetry model developed by Hui et al. was extended to provide realistic beta-dose estimates for organs in mice that received therapeutic radiopharmaceuticals containing 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177 Lu. Major organs in this model included the liver, spleen, kidneys, lungs, heart, stomach, small and large bowel, thyroid, pancreas, bone, marrow, carcass, and a 0.025-g tumor. The study as reported in this paper verifies their results for 90Y and extends them by using their organ geometry factors combined with newly calculated organ self-absorbed fractions ...
A laboratory stream consisting of two stream sections interrupted by two pools was filled with a mixture of tap water and organically enriched water from rivers nearby. Bottom sediment material, Potamogeton pectinatus, macro-invertebrate organisms, as well as the mosquito fish, Aplocheilichthys johnstonii were collected from rivers around Johannesburg and introduced into the laboratory stream. After initial acclimatization, the distribution of the isotope "3"2P through this laboratory stream was followed. Absorption of this isotope by benthic algae, Potamogeton pectinatus, several macro-invertebrate organisms as well as Aplocheilichthys johnstonii was recorded.
Iodine-131 MIBG, a radiolabeled adrenergic neuron-blocking agent, decreased rapidly from the heart and liver of patients with adrenergic dysfunction and pheochromocytoma when compared with eight controls. However, there was no significant difference in the rate of (/sup 131/I)MIBG decrease in these organs between controls and patients in the intervals subsequent to 4 hr. These findings suggest that adrenergic neuronal uptake of (/sup 131/I)MIBG in these organs is smaller in the patients than in the controls. Measurements of time-activity relationships of radioiodinated MIBG may be useful for assessment of adrenergic function of these organs and thus of generalized disorders of adrenergic innervation.
Organ and tissue doses and integral doses in patients due to diagnostic x-ray examinations of the chest and of the head will be presented. These data have been obtained by measuring the dose distributions in man phantoms by LiF-dosimetry. The data will be compared with data obtained by Monte-Carlo calculations. To obtain average organ doses for a special type of examination for the population or for a specified subpopulation in the variation of the exposure, data due to the different techniques used by the different radiologists has to be known. Such data will be presented. The results of the investigation will be discussed in connection with the concept of the 'somatic significant.
One of the major scientific and technological challenges for the production of flexible organic electronic devices is the device protection against atmospheric molecule permeation, which causes corrosion reducing its operation and lifetime. In this work, Spectroscopic Ellipsometry has been implemented to investigate the influence of silicon dioxide nanoparticles on the optical properties of hybrid polymers. The spectra analysis revealed valuable information about the electronic and vibrational response as well as the cross-linking mechanisms of these materials. The correlation of the optical properties with the synthesis parameters and the barrier response will contribute towards their optimization in order to be used as high barrier coatings for flexible organic electronics applications.
Intensive measurements of organic acids, inorganic acids, aldehydes and peroxyacetyl nitrate (PAN) in urban air were carried out at a Southern California smog receptor site, Glendora, CA, August 12-22, 1986. The objective of this project was to augment the data base regarding organic acids in urban air and to assess their role with emphasis on ambient levels, diurnal variations, phase distribution, emissions, in-situ formation and removal. The relative abundance of organic acids and inorganic acids was determined for the first time from simultaneous measurements carried out during this study.
The anaerobic biogasification of organic wastes generates two useful products: a medium-Btu fuel gas and a compost-quality organic residue. Although commercial-scale digestion systems are used to treat municipal sewage wastes, the disposal of solid organic wastes, including municipal solid wastes (MSW), requires a more cost-efficient process. Modern biogasification systems employ high-rate, high-solids fermentation methods to improve process efficiency and reduce capital costs. The design criteria and development stages are discussed. These systems are also compared with conventional low-solids fermentation technology.
Capacity is defined as the power resulting from the specific position of a company in a network organization. This article extends the theory of network organizations to examine Mazda?s Yokokai Keiretsu, and proposes a new approach to calculating a firm?s capacity in a network. Capacity is divided into two categories, take-in capacity and take-out capacity, and the gap between them is called the capacity difference. We analyze the impact of capacity difference as a determinant of corporate performance in network organizations, thus providing a new perspective for successful corporate management.
This paper presents a self-organizing power system stabilizer (SOPSS) which use the Fuzzy Auto-Regressive Moving Average (FARMA) model. The control rules and the membership functions of the proposed logic controller are generated automatically without using any plant model. The generated rules are stored in the fuzzy rule space and updated on-line by a self-organizing procedure. To show the effectiveness of the proposed controller, comparison with a conventional controller for one-machine infinite-bus system is presented.
BackgroundDuplications of stretches of the genome are an important source of individual genetic variation, but their unrecognized presence in laboratory organisms would be a confounding...Full Text Available
The adverse effects of aging of other organs (ovaries at menopause) on the skeleton are well known, but ironically little is known of skeletal aging itself. Evidence indicates that age-related...Full Text Available
The lipid composition of skin is important to a variety of functions served by this organ. Therefore, skin expresses multiple enzymes that synthesize and metabolize lipids. An important class of lipid...Full Text Available
Denturism, an organized movement by dental laboratory technicians to increase their control over the provision of denture services to the public, has generated a great deal of controversy among members...Full Text Available
Mitochondria are the major sites where energy is produced in the cell. Functions of organs such as the heart which has high energy demand are seriously affected by dysfunction of mitochondria....Full Text Available
This article discusses issues in teaching secure coding in the context of both academic institutions and training organizations. The emphasis is on the importance of assurance. There is also some discussion of the role of checklists.
BackgroundWith the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional...Full Text Available
Strong coupled organic-inorganic microcavities device has been realized and studied. One of the two cavities contains an organic thin film of tetrakis(4-methoxyphenyl)porphyrin, whereas the other microcavity is a dielectric structure coupled to the organic one by means of a LiF/ZnS Bragg mirror. Reflectivity spectra show the presence of two well defined cavity dips. We observe an energy splitting of the two cavity-modes. Despite only one cavity contains the active layer, the photoluminescence spectra display two peaks at the same energy of the reflectivity dips. These observations indicate the strong coupling of the two cavities. The comparison of the diagonalized effective Hamiltonian with the observed resonances further confirms the strong coupling.
The oviduct is an exquisitely designed organ that functions in picking-up ovulated oocytes, transporting gametes in opposite directions to the site of fertilization, providing a suitable environment...Full Text Available
The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function,...Full Text Available
In the wake of the 2010 earthquake in Haiti, medical relief organizations and individual practitioners mobilized to provide assistance. Here, an emergency medicine physician who worked with a Louisiana-based...Full Text Available
BackgroundAlternative splicing is an important mechanism mediating the diversified functions of genes in multicellular organisms, and such event occurs in around 40-60% of human...Full Text Available
ConspectusSelf-assembly allows for the preparation of highly complex molecular and supramolecular systems from relatively simple starting materials. Typically, self-assembled...Full Text Available
Safety in general and harmonization of International Maritime Organization rules on mobile offshore drilling rig operation in particular are discussed. The improvement of the industry's safety record is also discussed.
Summary: The increasing emergence of antimicrobial-resistant organisms, especially methicillin-resistant Staphylococcus aureus (MRSA), has resulted in the increased...Full Text Available
Endogenous opioid peptides are substances involved in cell communication. They are present in various organs and tissues of the male and female reproductive tract, suggesting that they may regulate...Full Text Available
Purpose: Reconstruction of organ doses of selected organs and tissues from radiographic settings and exposure data collected during chest X-ray examinations of children of various age groups performed in Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007. Materials and Method: The dosimetric data of all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 119 150 chest radiographs of all age groups. Reconstruction of organ doses in 40 organs and tissues in X-ray examinations of the chest was performed based on the conversion factor concept. Results: The radiation exposure of organs in projection radiography is determined by the exact ...
Researchers have identified as effective and worthy of broader dissemination a variety of intervention strategies to promote physical activity among older adults. This paper reports results of a community-organizing approach to disseminating evidence-based interventions in a sustainable way: The Southeast Seattle Senior Physical Activity Network (SESPAN). SESPAN was implemented in Southeast Seattle, a group of multicultural neighborhoods extending 8?miles southeast of downtown Seattle, with a population of 56,469 in 2000, with 12% (7,041) aged 65 and older. The SESPAN organizing strategy involved networking to: (1) make connections between two or more community organizations to create new senior physical activity programs; and (2) build coalitions of community groups and organizations to a...
BackgroundEmphysematous cholecystitis is a variant of acute cholecystitis which is generally caused by gas-forming organisms. Emphysematous cholecystitis may cause gas spreading...Full Text Available
Eukaryotic genomes are packaged in two basic forms, euchromatin and heterochromatin. We have examined the composition and organization of Drosophila melanogaster heterochromatin in...Full Text Available
In ozonization of polyfunctional and humic acids in icy acetic acid the whole of organic carbon can turn into a soluble form. Mono - and dicarboxylic acids of normal structure were found in the products of ozonization.
There is a mismatch between the documentation of the visually guided behaviors and visual physiology of decapods (Malacostraca, Crustacea) and knowledge about the neural architecture of their...Full Text Available
Like few other organs, the skin is continuously exposed to multiple exogenous and endogenous stressors. Superimposed on this is the impact of psychological stress on skin physiology and pathology....Full Text Available
We summarize recent developments in x-ray microscopy of polymers by focusing on the characterization of organic electronic devices. The quantitative compositions of model polymer blends have been mapped at a resolution of {approx}35 nm. Since it could be inferred that these devices have structures smaller than 35 nm, quantitative compositional mapping at length scales below the present resolution limit of x-ray microscopy is required. Organic devices thus serve to both highlight the success of NEXAFS microscopy to date, but to also outline the very real need for higher spatial resolution. New approaches to create improved optics or different acquisition modalities are required if x-ray microscopy is to make sustained contributions to such an important area of research as organic devices.
Jun 4, 2004 ... On a two-year trip to Mars, according to one estimate, a crew of six humans will generate more than six tons of solid organic waste--much of ...
Jun 21, 2006 ... The competition is organized by the Marine Advanced Technology Education Center (MATE) and Marine Technology Society's (MTS) ROV Committee. ...
... WHS- Washington Headquarters Service ... but also with respect to other Joint, National and ... unit of action (UA) combat team or task force is organized ...
Fourier-transform infrared (FTIR) spectroscopy was used to monitor amino acids, organic acids, and changes during ripening. Twelve Cheddar cheese samples were ripened for 73 days and samples were drawn periodically. Water-soluble fractions of samples were analyzed by gas chromatography (20 amino acids), liquid chromatography (three organic acids), and FTIR spectroscopy (4000-700 cm-1). Spectra were correlated with chromatographic data and ripening events and analyzed by multivariate statistics to develop prediction and classification models. Most models showed a good fit (correlation coefficient > or =0.89) and could predict the levels of amino acids and organic acids and age of the cheese in less than 20 min. Lactic acid, leucine, glutamic acid, asparagine, phenylalanine, and valine were ...
... of electronic systems (satellite terminals, radio and ... helps organizations investigate the stochastic nature of ... cycle time, maximum queue lengths, and ...
Purpose: To enable the solidification of liquid waste containing radioactive substance in a free shape with large volume reduction ratio without a pulverizing step by producing solute in the liquid waste as a slurry in a predetermined organic solvent and forming it into a cake by mechanical exfoliation. Method: Liquid waste containing suitably concentrated radioactive substances is supplied to a centrifugal thin film evaporator together with an organic agent having a higher boiling point than water and a non aqueous solution to evaporate the water content, the solute in the waste is produced as a slurry in the organic solvent, and removed as cake-state solute slightly residued with the organic solvent by the mechanical exfoliation such as centrifugal exfoliation or settling exfoliation from the slurry-state liquid. Accordingly, it can be increased in size as compared with the powder reduced in volume of ...
The acute acetoclastic methanogenic inhibition of several inorganic and organic arsenicals was assayed. Trivalent species, i.e., methylarsonous acid and arsenite, were highly inhibitory, with 50% inhibitory...Full Text Available
... XVIII Airborne Corps forces grew from one brigade of the 82nd Airborne Division to a multi-national organization of five full divisions (Eastern Area ...
SYNOPSISPreterm infants are at risk for both iron deficiency and iron overload. The role of iron in multiple organ functions suggests that iron supplementation is essential for...Full Text Available
The need for material standards in the field of clinical immunology, together with the mode of operation of the combined World Health Organization/International Union of Immunological Societies programme...Full Text Available
Aging is a biological process that affects most cells, organisms and species. Human aging is associated with increased susceptibility to a variety of chronic diseases, including cardiovascular disease,...Full Text Available
Analytical procedures are described for the determination of organic compounds, metals and radioisotopes in environmental materials, human tissues, urine, feces, and waste water.
The fields in this dataset are: Date Lake Depth Dissolved Organic Carbon Dissolved carbohydrates and amino acids Inorganic Nutrient Concentrations Primary ...
The following topics are discussed: program goal and objectives, program organization, and program status. Current program projects are described. (MHR)
The eye is an easily accessible, highly compartmentalised and immune-privileged organ that offers unique advantages as a gene therapy target. Significant advancements have been made in understanding...Full Text Available
The research for the development of flexible organic electronic devices (FEDs) is rapidly increasing worldwide, since FEDs will change radically several aspects of everyday life. Although there has been considerable progress in the area of flexible inorganic devices (a-Si or solution processed Si), there are numerous advances in the organic (semiconducting, conducting and insulating), inorganic and hybrid (organic-inorganic) materials that exhibit customized properties and stability, and in the synthesis and preparation methods, which are characterized by a significant amount of multidisciplinary efforts. Furthermore, the development and encapsulation of organic electronic devices onto flexible polymeric substrates by large-scale and low-cost roll-to-roll production processes will allow their market implementation in numerous application areas, including displays, lighting, photovoltaics, ...
The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues...Full Text Available
Social organisms that cooperate with some members of their own species, such as close relatives, may fail to cooperate with other genotypes of the same species. Such noncooperation may take the form...Full Text Available
Effective and efficient strategic decision making is the backbone for the success of a business organization. These decision making processes, used among its competitors in a particular industry, determine whether the business will continue to survive or not. In this research, fuzzy logic (FL) concept and game theory are being used to model strategic decision making processes by business organizations. Competition between business organizations is viewed as a game with each business organization as a player. A player formulates his own decisions by making his strategic moves based on uncertain information. This is the information he has about the opponents with respect to prevailing or anticipated market demand, cost of production, marketing, consolidation efforts and some other business v...
Contact precautions are implemented to reduce transmission of multidrug-resistant organisms but may also increase hospital costs and patient complications. The goal of this study was to determine...Full Text Available
Despite the fact that humans are exposed to multiple forms of mercury (elemental, inorganic, and organic), most research on mercury toxicity has focused on methylmercury (MeHg) and on neurotoxic outcomes and mechanisms. Recent work has indicated that the immunotoxic effects of mercury compounds may be significant contributors to human disease as well as mechanistically relevant to other target organ toxicities. In this study, we compared the effects of inorganic Hg (iHg) to organic Hg species (MeHg and ethylmercury, EtHg) in human peripheral blood mononuclear cells (PBMCs) in vitro at sub-cytotoxic concentrations, using methods developed to characterize response of human PBMCs to iHg in vitro. PBMCs were isolated from six volunteer blood donors (three males and three females) and cultured ...
Conditions of the separation and detection of organic and inorganic anions by gradient ion chromatography and suppressed conductivity detection were studied, and the procedure of gradient elution was optimized. A detection limit of 1 x 10{sup -3} {mu}g x L{sup -1} was obtained using the pre-concentrated column and most relative standard deviations obtained in the determination of seven organic and inorganic anions were below 5%. This method was proved to be simple, rapid and accurate for the separation and determination of low-molecular-weight organic acids and inorganic anions and could be applied in the analysis of the samples from water and steam systems of thermal power plants with satisfactory results. (orig.)
Systemic lupus erythematosus (SLE) persists as a chronic inflammatory autoimmune disease and is characterized by the production of autoantibodies and immune complexes that affects multiple organs....Full Text Available
We demonstrate control and improvement of charge injection in organic electronic devices by utilizing self-assembled monolayers (SAMs) to manipulate the Schottky energy barrier between a metal electrode and the organic electronic material. Hole injection from Cu electrodes into the electroluminescent conjugated polymer poly[2-methoxy,5-(2{sup {prime}}-ethyl-hexyloxy)-1,4-phenylene vinylene] was varied by using two conjugated-thiol based SAMs. The chemically modified electrodes were incorporated in organic diode structures and changes in the metal/polymer Schottky energy barriers and current{endash}voltage characteristics were measured. Decreasing (increasing) the Schottky energy barrier improves (degrades) charge injection into the polymer. {copyright} {ital 1997 American Institute of Physics.}
Objectives:The efficacy of user-defined subject tagging and software-generated subject tagging for describing and organizing cancer blog contents was explored.Methods:The...Full Text Available
The phytochrome photoreceptors and the circadian clock control many of the same developmental processes, in all organs and throughout the growth of Arabidopsis plants. Phytochrome A (phyA) provides...Full Text Available
The dipteran parasitoids Therobia leonidei and Homotrixa alleni (Tachinidae) use acoustic cues to locate their calling tettigoniid (Ensifera, Orthoptera) hosts. The sexually dimorphic tympanal organs of both fly species are located at the prosternum. For comparison a homologous chordotonal organ in the non-hearing fly Phormia regina, Meigen (Phoridae) is also described. The scolopidial sense organs of the ears have approximately 180 sensory cells in Th. leonidei and 250 cells in H. alleni. Interspecific analysis indicates that the cell number and arrangement might be genus specific in Tachinidae. The mononematic scolopidia, each with one sensory cell, are of different sizes and insert at the tympanal membrane. Large scolopidial units (diameter of sensory cells up to 50??m) extend longitudi...
In recent years, there have been major advances in knowledge of Vibrio species and related organisms that are responsible for diarrhoeal diseases, particularly V. cholerae...Full Text Available
... Mineral and Organic Matter in the Coastal and Near-Coastal Ocean. ... Personal Author(s) : Stavn, Robert H. ; Spiering, Bruce A. ; Gould, Richard W ...
Vibrios are ubiquitous and abundant in the aquatic environment. A high abundance of vibrios is also detected in tissues and/or organs of various marine algae and animals, e.g., abalones, bivalves, corals,...Full Text Available
Haloorganic biocides are widely employed as soil fumigants to combat the destructive action of plant parasitic nematodes and fungi. These substances are dehalogenated by soil organisms, principally...Full Text Available
The early Miocene Pedregoso Formation is one of the numerous formations rich in organic matter within the stratigraphic record of the Urumaco Trough, in the central area of the Falcon Basin. Due to its lithological characteristics and stratigraphic position, this formation is of great interest regarding the basin's petroliferous systems. The evaluation of various inorganic and organic geochemical parameters indicates that the organic matter is primarily of marine origin, deposited in a marine carbonate environment typical of reefal systems, under oxic-to-dysoxic conditions. The low variability in the TOC concentrations and in the distributions of the biomarkers extracted from the samples suggests that the paleoenvironmental conditions and the organic-matter supply remained approximately co...
New methods for the reduction and remediation of hazardous wastes like carcinogenic organic solvents, toxic materials, and nuclear contamination are vital to environmental health. Procedures for effective...Full Text Available
... on some results we obtained, using stochastic methods as ... choice between two customers in a queue and one ... with the terminal of edge I being the ...
Mung bean seedlings inoculated with Enterobacter asburiae PSI3, a gluconic acid-producing rhizosphere isolate, enhanced plant growth in the presence of phytotoxic levels of Cd2+ in gnotobiotic pot experiments as compared to the uninoculated Cd-treated plants. Addition of organic acids to Cd-stressed seedlings promoted root elongation. Hematoxylin competition assays showed that organic acids could displace Cd2+ from the Cd2+: hematoxylin complex in the same order of effectiveness as was found for restoration of root net elongation viz. oxalate?>?malate?>?succinate while gluconate was effective at higher concentrations. Root associated Cd2+, assessed by hematoxylin staining of roots was found to be reduced when roots were treated with organic acid. Cd stress increased antioxidant enzymes suc...
The challenges of lung cancer radiotherapy are intra/inter-fraction tumor/organ anatomy/motion changes and the need to spare surrounding critical structures. Evolving radiotherapy technologies, such...Full Text Available
The role of apoptosis or programmed cell death in the regulation of development and maintenance of homeostasis in multicellular organisms is well established. During the last decade, naturally...Full Text Available
BackgroundMultilevelness is a defining characteristic of complex systems. For example, in the intestinal tissue the epithelial lining is organized into crypts that are maintained...Full Text Available
Cyanobacteria have become a major model system for analyzing clock phenomena. The temporal program in this organism enhances fitness in rhythmic environments and is truly global—essentially...Full Text Available
Recently the ISO standards organization has requested the PV community to establish AMO calibration methodologies for space solar cells. The PV community responded by organizing a series of workshops to review and recommend AMO calibration techniques. One of the activities of the workshop is to review the various calibration methodologies and conduct a comprehensive uncertainty analysis of each method. This paper outlines NASA`s methodology of AMO calibration using the high altitude aircraft method.
Degradation of cellulosics or starch in alkaline solution produces mostly organic acids which are monocarboxylic in nature. Seven of the organic acids have been identified as formic, acetic, glycolic, lactic, 2-hydroxybutyric, 2-hydroxyisobutyric and 2-hydroxyvaleric acids. In total, their yields amount to 41-46% of starting material weight.
... (last modified: 10/22/2002) Organizations Saratoga Foundation (last modified: 02/11/2003) Actions You Can Take Global Response (last modified: 05/10/2000) Organizations University of Pittsburgh Cancer Institute - Center for Environmental Oncology (last modified: 01/14/2005) Home | Site Map | About EnviroLink | Advanced Search | Suggest ...
Scheme of theoretical method of molecular configuration definition for small organic molecules in solution has been presented. The method bases on measurements of nuclear Overhauser effects for proton-proton interactions and molecular mechanics calculations. 3 refs, 1 fig.
Our work is towards mechanistically understanding interactions of unsaturated bacterial biofilms and their extracellular polymeric substances (EPS) with actinide metals and metal surrogates under vadose zone conditions. Because metal contaminants in the vadose zone co-occur with organic pollutants, some of our work has included experiments with organic pollutants.
Only a small number of radiation accidents in the United States have been severe enough to result in multi-organ failure (MOF). Medical details of selected medical misadministration and criticality cases are reviewed, with an emphasis on pathophysiology. The four criticality cases are particularly relevant for analysis of MOF, since medical treatment was supportive and did not appreciably alter the clinical evolution of radiation injury. PMID:15975871
Plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic...Full Text Available
Radiation therapy has shown definite technical improvement due to application of proton beam irradiation. Clinical results of proton beam therapy also suggested enlargement of indication ranges in radial treatment and decrease of post radiation damages of the treatment of cancers in deep-seated organs. Inprovement of result in cancer therapy could be expected by this treatment technique in the future.
The possibility of modifying the functional composition of humic acids by gas-phase ozonation of bed-oxidized brown coal was examined. About 90% of the organic matter of brown coal was converted to low-molecular weight soluble oxygen-containing products by stepwise liquid-phase ozonation (in chloroform and acetic acid).
A piezoelectric biosensor substrate useful for immobilizing biomolecules in an oriented manner on the surface of a piezoelectric sensor has a ladder polymer of polyacrylonitrile. To make the substrate, a solution of an organic polymer, preferably polyacrylonitrile, is applied to the surface of a piezoelectric sensor. The organic polymer is modifying by heating the polymer in a controlled fashion in air such that a ladder polymer is produced which, in turn, forms the attachment point for the biomolecules comprising the piezoelectric biosensor. 3 figs.
Unequal segregation of cell fate determinants at mitosis is a conserved mechanism whereby cell fate diversity can be generated during development. In Drosophila, each sensory organ...Full Text Available
The main aim of sanitary pass-control regime is to prevent propagation of radioactive contamination outside the area of emergency-rescue works and guarantee of sanitary treatment of all persons having radioactive contamination. The paper has studied the questions of organization of sanitary pass-control regime, arrangement of sanitary treatment of the injured persons and rendering first aid in case of radioactive contamination of wounds. 5 refs.
The organization of lin genes and IS6100 was studied in three strains of Sphingomonas paucimobilis (B90A, Sp+, and UT26) which degraded hexachlorocyclohexane...Full Text Available
A self-organizing particle swarm is presented. It works in dissipative state by employing the small inertia weight, according to experimental analysis on a simplified model, which with fast convergence. Then by recognizing and replacing inactive particles according to the process deviation information of device parameters, the fluctuation is introduced so as to driving the irreversible evolution process with better fitness. The testing on benchmark functions and an application example for device optimization with designed fitness function indicates it improves the performance effectively.
The effect of small misch metal additions (0.25 to 1 wt.%) on the corrosion behaviour of aluminium was studied through electrochemical polarization in 0.1 N inorganic and organic acids at room temperature. It has been observed that rare earth addition improves the corrosion resistance of aluminium. (orig.).
"Nine of CERN 's 20 Member States today a signed new Protocol on privileges and immunities. This brings the Organization into line with other European intergovernmental organizations, such as the European Space Agency and the European Southern Observatory, which already enjoy international status in all of their Member States" (2
Mission-directed public-sector research facilities are experiencing increasingly severe budget environments while seeing expanding missions and responsibilities. In an effort to identify research leveraging methodologies an information search was conducted in conjunction with some efforts to find the proper links to systems engineering fundamentals. The result is an initial model for use in a pre-concept/phase-1 engineering design organization, with a goal of improving the organizations performance.
Chemical oxidation is a treatment technology that uses powertul chemical oxidizers to destroy organic contaminants. Typical oxidizers used in chemical oxidation processes include ozone, hydrogen peroxide, chlorine, and potassium permanganate. The chemical reaction products are usually simple organic compounds, such as carboxylic acids, and/or inorganic compounds, such as carbon dioxide, water, and simple inorganic complexes (e.g., chloride salts, in the case of chemical oxidation treatment of chlorinated solvents).
Organic molecules are a significant and highly varied component of atmospheric aerosols. Measurement of aerosol composition and improvements in our understanding of the complex chemistry involved in their formation and aging are being aided by innovations in soft ionization aerosol MS. (To listen to a podcast about this feature, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html.). PMID:21275431
Occupational and environmental exposure to organic ligands, solvents, fuel hydrocarbons, and polychlorinated biphenyls are linked with increased risk of hematologic malignancies. DOE facilities and waste sites in the U.S. are contaminated with mixtures of potentially hazardous chemicals such as metals, organic ligands, solvents, fuel hydrocarbons, polychlorinated biphenyls and radioactive isotopes. A major goal of this project was to establish linkage between chemical/radiation exposure and induction of genomic damage in target populations with the capability to undergo transformation.
Short review of works on astatine chemistry carried out by authors for the last thirty years are done. Discovery of single-charged cation stable in aqueous solutions is predominant attainment of authors in the branch of inorganic chemistry. The first successful synthesis of heptavalent astatine compounds is a new and significant result of the last years. New direction in the chemistry of the fifth halogen is organic chemistry of astatine
...contributions from the following fields: Catalytic elimination of environmental pollutants, such as nitrogen oxides, carbon monoxide, sulfur compounds, chlorinated and other organic compounds, ...contributions from the following fields: Catalytic elimination of environmental pollutants, such as nitrogen oxides, carbon monoxide, sulfur compounds, chlorinated and other organic compounds, ...
...DEPARTMENT OF THE ARMY MILITARY RESERVATIONS AND...REGULATIONS AFFECTING MILITARY RESERVATIONS ...or guide service, dog training for reimbursement...non-profit organizations working in the public...profit, including dog training for reimbursement...non-profit organizations working in the public...
Perylene bisimides (PBIs) represent an important class of organic n-type semiconductors exhibiting a relatively high electron affinity among large-band-gap materials. Herein synthesis and characterization of several unsymmetrical N-substituted PBI dyes is presented and the thermotropic behavior, which is strongly affected by the respective N-substituents was investigated. Two different series of highly soluble and fluorescent derivatives have been synthesized: (1) PBIs bearing swallow-tailed alkyl chains, different in size or (2) one swallow-tailed alkyl chain and one branched oligoethylenglycolether. Synthesis of these PBIs is generally feasible by two distinct divergent synthesis approaches. Thermotropic behavior was studied by DSC, POM and XRD measurements. Inherent {pi}-{pi} interactions between cofacially orientated perylene molecules and the elliptic shape of the molecule favor the ordering in columns and self-organized architectures. ...
Sediment trap fluxes of solids, organic carbon, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were measured in Lake Superior in 1984 and 1985. Mass fluxes from surface waters ranged from 0.14 to 1.1 g/m{sup 2}{center dot}day and increased near the lake floor due to resuspension of surficial sediment and horizontal transport in the benthic nepheloid layer. Organic matter fluxes from surface water ranged from 60 to 90 mg of C/m{sup 2}{center dot}day, with {approximately}5% of organic carbon settling from surface waters accumulating in bottom sediments. Concentrations of PCBs and PAHs are enriched 10-100 times on settling particles relative to those on suspended particles. Resultant settling fluxes are 10-100 times greater for several PCB and PAH compounds than net accumulation rates in bottom sediments, indicating the effective and rapid recycling in the benthic region. Biological packaging of ...
The effect of yttrium substitution at the lanthanum site on the superconducting properties of La_1_-_xY_xO_0_._9F_0_._1FeAs ('x' = 0, 0.10, 0.20, 0.30, 0.50 and 0.60) oxypnictides has been studied. Powder X-ray diffraction studies confirm single phases till x = 0.1 beyond which minor amount of Y_2O_3 is observed. The temperature dependence of resistivity measurements confirm the superconducting transition temperature (T_c) of 34.8 (#+-#0.05) K and corresponding Meissner transition at 34.3 K in the 'x' = 0.3 composition which is higher than that reported for the parent phase (LaO_0_._9F_0_._1FeAs (T_c = 28 K)). Further increase in the concentration of yttrium leads to broadening and suppression of the superconducting transition. The value of H_c_2 at zero temperature is estimated to be about 60.5 T. The Seebeck coefficient (S) shows a negative sign indicating that the major contribution to the conductivity is by electrons. The Hall coefficient (R_H) also remains negative throughout the ...
Cold deformation of YBa{sub 2}Cu{sub 3}O{sub 7-x}(phase 123, T{sub c} = 88.5-92 K) powders and strips causes partial decomposition of the 123 phase, a reduction in the degree of orthorhombicity of the structure up to almost complete degradation, and a decrease in T{sub c}. When they are deformed, yttrium high temperature superconductors acquire basal (001) (110) texture with high pole density (13-15 arbitrary units), low scattering angle ({+-} 6deg--7deg from the normal direction), and a weak preference for a, b or a + b in the rolling direction; traces of (139) orientations may also be found. This texture is known to be favourable for increasing j{sub k}. The combined effect of cold deformation and a carbon-containing binder leads, however, to a complete loss of superconductivity at 77 K or above. Depending on the regime of subsequent annealing, the following effects may be observed: degradation of the orthorhombic structure with a decrease in T{sub c}; ...
A processing technique for A-15 compounds which has improved mechanical and superconducting properties has been developed. This technique consists of rapid solidification of the alloy by the chill block spinning machine (CBSM) to form amorphous ribbons and by subsequent annealing crystallizes the stable or metastable fine grain flexible A-15 structure. The CBSM has been modified so that all the processing parameters could be controlled and optimized for each alloy composition. By the improved CBSM it was possible to form amorphous Nb_3Si, Nb_3Ge and Nb_3(AlSi) ribbons with more than 80% reproducible rate. Critical current density measurements are limited by contact resistance. A Cu plating technique was introduced in this research that made the contact resistance three orders of magnitude lower than that obtained by other methods. This plated coating also gave an additional mechanical support to the sample and acted as a shunt for thermal stabilization of the sample. J_c of Nb_3Ge at ...
A processing technique for A-15 compounds which has improved mechanical and superconducting properties has been developed. This technique consists of rapid solidification of the alloy by the chill block spinning machine (CBSM) to form amorphous ribbons and by subsequent annealing crystallizes the stable or metastable fine grain flexible A-15 structure. The CBSM has been modified so that all the processing parameters could be controlled and optimized for each alloy composition. By the improved CBSM it was possible to form amorphous Nb{sub 3}Si, Nb{sub 3}Ge and Nb{sub 3}(AlSi) ribbons with more than 80% reproducible rate. Critical current density measurements are limited by contact resistance. A Cu plating technique was introduced in this research that made the contact resistance three orders of magnitude lower than that obtained by other methods. This plated coating also gave an additional mechanical support to the sample and acted as a shunt for thermal stabilization of the sample. ...
The complex phase relationships near the BaO-poor region of the quaternary Ba-Sm-Y-Cu-O oxide system prepared in pure air (pO2=22 kPa, 950 oC) and in 0.1% O2 (pO2=100 Pa, 810 oC) have been determined. This investigation also included the subsolidus compatibilities in ten subsystems (Ba-Sm-Y-O, Ba-Sm-Cu-O, Ba-Y-Cu-O, Sm-Y-Cu-O, Ba-Sm-O, Ba-Y-O, Ba-Cu-O, Sm-Y-O, Sm-Cu-O, and Y-Cu-O), and the homogeneity range of five solid solutions (Ba(SmxY2-x)CuO5, (Sm,Y)2O3, (Sm,Y)2CuO4, (Y,Sm)2Cu2O5, and Ba(Sm,Y)2O4). The single phase range of the superconductor solid solution, (Ba2-xSmx)(Sm1-yYy)Cu3O6+z, and the phase compatibilities in its vicinity, which are particularly important for processing, are described in detail. The phase equilibrium data of the Ba-Sm-Y-Cu-O system will enable the improvement of the intrinsic superconducting properties of second-generation wires, and facilitate the flux-pinning process. -- Graphical Abstract: Phase diagram overview of the Ba-Sm-Y-Cu-O ...
The purpose of this work was to investigate the optical properties of several high T/sub c/ compounds in the form of sputtered films. The measurements are used toward this end: optical absorptance (using a calorimetric technique near 4.2K), which yields (after Kramers-Kronig analysis) the complex dielectric function, and thermoreflectance (which measures the change in reflectance in the optical range when a 1 to 10/sup 0/K temperature wave is applied), performed at two ambient temperatures (80 and 300/sup 0/K), yielding the differential dielectric function. The sputtered films included Nb/sub 3/Ge, Nb/sub 3/Al, V/sub 3/Ga and Nb/sub 3/Ir. It is noted that Nb/sub 3/Ir is not a high T/sub c/ superconductor. The thermoreflectance on the bulk samples V/sub 3/Si, V/sub 3/Ge and single crystal Cr/sub 3/Si were not performed because the samples were not in the form of thin films. The thermomodulation studies are correlated with the absorptance measurements in comparison ...
The purpose of this work was to investigate the optical properties of several high T/sub c/ compounds in the form of sputtered films. The measurements are used toward this end: optical absorptance (using a calorimetric technique near 4.2K), which yields (after Kramers-Kronig analysis) the complex dielectric function, and thermoreflectance (which measures the change in reflectance in the optical range when a 1 to 10_0K temperature wave is applied), performed at two ambient temperatures (80 and 300_0K), yielding the differential dielectric function. The sputtered films included Nb"3Ge, Nb"3Al, V"3Ga and Nb"3Ir. It is noted that Nb"3Ir is not a high T/sub c/ superconductor. The thermoreflectance on the bulk samples V"3Si, V"3Ge and single crystal Cr"3Si were not performed because the samples were not in the form of thin films. The thermomodulation studies are correlated with the absorptance measurements in comparison to band structure calculations. When ...
A study of the magnetic properties and the heat capacity as functions of temperature and magnetic field of two ternary carbides RNiC_2, where R=La and Ce, confirms that LaNiC_2 becomes superconducting at T_c=2.7thinspK, and that CeNiC_2 orders antiferromagnetically below 18thinspK. LaNiC_2 is a conventional superconductor with a critical field of 900 Oe at T=2thinspK. CeNiC_2 obeys the Curie-Weiss law between 50 and 300thinspK showing the nearly full Ce"3"+ magnetic moment, p_e_f_f=2.47(1)#mu#_B, and has a negative paramagnetic Weiss temperature #THETA#_p=-18.3(8)thinspK. A low net magnetic moment in the ordered state, which is far from saturation in a magnetic field of 5thinspT, is consistent with an antiferromagnetic ground state. Below 20thinspK CeNiC_2 shows multiple-step magnetic transitions at 18, 10, and 2.4thinspK. Both LaNiC_2 (in the normal state) and CeNiC_2 have the same electronic heat capacity, #gamma#=6.5(2)thinspmJ/molthinspK"2, which is typical for ...
The structural transition and anomalous properties of the high temperature A-15 superconductors have been investigated from two different standpoints. The first is a Landau theory based on Gorkov's physical model of a Peierls-like charge density wave (CDW) transition involving electronic CDW order parameters coupled to phonon coordinates. Pretransition elastic anomalies, softening of the [1 anti 10] transverse ([1 anti 10] polarized) phonon, sublattice distortions, variation of transition temperature with stress and alloying and other effects have been accurately predicted, and a detailed comparison is made with experimental results. Central peaks in neutron scattering are shown to be non-dynamic in nature and no pretransition forbidden (300) reflection is predicted. The GAMMA_1_2 optic mode does not go soft at the transition, though its frequency is expected to be temperature dependent right up to room temperature. A tight binding, two (3-D) band model of the A-15 ...
A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 to 50 gms of V-(14 approx. 19 at. %) Ga and Nb-(13 approx. 22 at. %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatures in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features demonstrated by the process are very attractive for practical applications. In the V-Ga system, transmission electron microscopy (TEM) studies revealed the A15 precipitates in an elongated form. However, for the Nb-Al samples, deformed and aged at 750/sup 0/C, TEM studies revealed A15 precipitation in fine equi-axed particles which formed as a semi-continuous network over sub-grain boundaries formed by the recovery of deformation-induced dislocations. In the V-Ga system, the maximum critical ...
Research highlights: {yields} The use of resonant photoemission in its 'core-hole clock' expression for the study of the dynamical charge transfer across hybrid organic-inorganic interfaces and for the intermolecular charge transfer in the bulk of organic thin films is reviewed. {yields} The electronic coupling to the substrate and the efficiency of charge transport across hybrid interfaces is different for individual electronic subsystems of the molecular adsorbate. {yields} The intermolecular charge transfer in the bulk of discotic liquid crystals occurs on the order of a few femtoseconds and is faster than expected from the macroscopic charge transport characteristics of the material. -- Abstract: The focus of this brief review is the use of resonant photoemission in its 'core-hole clock' expression for the study of two important problems relevant for the field of organic electronics: ...
The organization of organic semiconductor molecules in the active layer of organic electronic devices has important consequences to overall device performance. This is due to the fact that molecular organization directly affects charge carrier mobility of the material. Organic field-effect transistor (OFET) performance is driven by high charge carrier mobility while bulk heterojunction (BHJ) solar cells require balanced hole and electron transport. By investigating the properties and device performance of three structural variations of the fluorenyl hexa-peri-hexabenzocoronene (FHBC) material, the importance of molecular organization to device performance was highlighted. It is clear from {sup 1}H NMR and 2D wide-angle X-ray scattering (2D WAXS) experiments that the sterically demanding 9,9-dioctylfluorene groups are preventing {pi}-{pi} intermolecular contact ...
To prove that two-layer, TBP-nitric acid mixtures can be safely stored in the Canyon evaporators, it must be demonstrated that a runaway reaction between TBP and nitric acid will not occur. Previous bench-scale experiments showed that, at typical evaporator temperatures, this reaction is endothermic and therefore cannot run away, due to the loss of heat from evaporation of water in the organic layer. However, the reaction would be exothermic and could run away if the small amount of water in the organic layer evaporates before the nitric acid in this layer is consumed by the reaction. Provided that there is enough water in the aqueous layer, this would occur if the organic layer is sufficiently thick so that the rate of loss of water by evaporation exceeds the rate of replenishment due to mixing with the aqueous layer. Bubbles containing reaction products enhance the rate of transfer of water from the aqueous layer to the ...
Abstract in english Human organism is interpenetrated by the world of microorganisms, from the conception until the death. This interpenetration involves different levels of interactions between the partners including trophic exchanges, bi-directional cell signaling and gene activation, besides genetic and epigenetic phenomena, and tends towards mutual adaptation and coevolution. Since these processes are critical for the survival of individuals and species, they rely on the existence of a c (more) omplex organization of adaptive systems aiming at two apparently conflicting purposes: the maintenance of the internal coherence of each partner, and a mutually advantageous coexistence and progressive adaptation between them. Humans possess three adaptive systems: the nervous, the endocrine and the immune system, each internally organized into subsystems functionally connected by intraconnections, to maintain the internal ...
Soil erosion and small annual additions of organic matter from plant-sources are the major causes of low organic-matter content in our soils. The tops of the plants, fallen to the soil- surface, remain there are incorporated, the plant-roots, shrubs, grasses. And other native plants contribution much towards the soil organic matter. Populus spp. Are grown commonly around farmers' fields in the state of Azad Jammu and Kashmir. A pot-experiment was conducted to study the effect of addition of populus euramericana leaves on various physical and chemical characteristics of the soil. Soil was kept at field-capacity level and incubated at room temperature for 10 months after adding 25, 50, and 75 g of Populus curamericana leaves per pot. Changes in organic-matter content. PH, cation-exchange capacity extractable potassium, water-holding capacity, and bulk density were investigated, after incubation for ...
N/C and S/C ratios show only minor differences between asphaltenes and coal on this basis, the asphaltenes continue to appear to be good surrogates for the characterization of organic acid rain precursors in coal. Alkylmethoxythiophene carboxylic acids (ATCA) are detected in all dichromate oxidation products analyzed to date. Relative concentrations of ATCA compounds are directly proportional to the sample`s bulk organic sulfur contents. Concentrations of ATCA compounds in oxidation products decrease upon repeated oxidation. This may indicate that the thiophenic groups tend to be located in external positions on the coal macromolecular structure and a high proportion of them can be stripped away with only one mild oxidation step. If true, this may make industrial-scale removal of organic sulfur easier than expected. Using analytical micropyrolysis-gas chromatography with a sulfur-selective flame photometric detector, it is ...
A meeting was held on October 15, 16, 17, 1990 to discuss the state of tritium safety and environmental effects. The meeting was organized with the help of the International Energy Agency planning committee consisting of K. Steinmetz, Y. Seki, G. Nardella, and G. Vivian. Representative of tritium production facilities and heavy water reactor power production were also involved. The meeting was organized to address seven topics in tritium safety that were thought to require further work. The topics were: (1) materials science, (2) environmental models, (3) environmental model validation, (4) tritiated organic compounds, (5) human dosimetry, (6) tritium sampling and measurement, and (7) long-term environmental databases.
The treatment of peat with the solutions of phosphoric, citric, and oxalic acids in concentrations of 10???4 and 10???2 mol/l at solid phase to liquid ratios of 1: 2.5 and 1: 5 increased the absorption of ammonia by 6.4???39.7%. The absorption of ammonia was higher than the concentration of doping ion-exchange groups by a factor of 5???2000. With the use of EPR and IR spectroscopy, it was found that this phenomenon was caused by the transformation of polyconjugation systems as a result of the interaction of acids with the organic matrix of peat by a macrocoordination mechanism, which also improved the technological characteristics of the resulting sorbents. The absence of the destruction of organic matter with the use of low concentrations of weak acids makes it possible to use these sorbe...
Understanding the dependence and interplay between architecture and function in biological networks has great relevance to disease progression, biological fabrication and biological systems in general. Recent research in complex systems and networks, presents methods to properly mine the architectural interdependence in networks. Guided by such work, we propose methods to associate organism characteristics with network topology by analyzing a large number of architectural patterns. We adopt an automated approach using 11 topological metrics from complex networks to characterize a collection of various kinds of biological networks. Principal component analysis and clustering allow us to extract the indispensable, independent and informative metrics. Using hierarchical linear modeling, we observe that organism characteristics associate with these metrics, surprisingly well. This work can serve as a stepping stone to cataloging biologically ...
The antimicrobial activity of simulated solar disinfection (SODIS) in the presence and absence of riboflavin against various protozoa and helminth organisms was investigated in this study. Assays were conducted in transparent 12 well microtitre plates containing a suspension of test organisms in the presence or absence of 250mM riboflavin. Plates were exposed to simulated sunlight at an optical irradiance of 550Wm^-^2 (watts per square metre) delivered from a SUNTEST(TM) CPS+ solar simulator. Aliquots of the test suspensions were taken at set time points and the viability of the test organisms was determined by either culture, microscopy or flow cytometry where applicable. With Acanthamoeba, Naegleria, Entamoeba and Giardia exposure to SODIS at an optical irradiance of 550Wm^-^2 for up to ...
The environmental behavior of antibiotics has attracted great research attention. However, their sorption mechanisms in soils/sediments are still unknown. Comparison of the sorption properties between the widely-studied hydrophobic organic contaminants (HOCs) and antibiotics may provide valuable insight to antibiotic sorption mechanisms. Thus, in this study batch experiments for pyrene (PYR), bisphenol A (BPA), and sulfamethoxazole (SMX) sorption were conducted on a sediment sample and its separated fractions. Our results showed the high sorption of PYR on black carbon and organic matter. Although high sorption of SMX was observed for both separated organic fractions (humic acids) and inorganic mineral particles, the original sediment particles showed relatively low sorption. Competitive s...
Abstract Superoxide dismutase (SOD) is ubiquitous in aerobic organisms and constitutes the first link in the enzyme scavenging system of reactive oxygen species. In the present study, species and organ diversity of SOD activity in a solution and in an in-gel assay system, as well as the effects of hydrogen peroxide (H2O2) on SOD activity, were investigated. In a solution assay system, SOD activity of jackfruit root, shoot, leaves, axes, and cotyledons, of maize embryos and endosperms, of mung bean leaves and seeds, of sacred lotus axes and cotyledons, and of rice and wheat leaves was increased by 1-15 mmol/L H2 O2. However, SOD activity in rice root and seeds, maize roots and leaves, mung bean roots and shoots, and wheat seeds was decreased by 1-15 mmol/L H2O2. The SOD activity of wheat ro...
Porcine pancreatic lipase immobilized on celite particles has been employed as a catalyst for the esterification of dodecanol and decanoic acid in a predominantly organic system. Solvent influence on the equilibrium position and on the catalyst activity has been studied using 20 solvents, including aliphatic and aromatic hydrocarbons, ethers, ketones, nitro- and halogenated hydrocarbons, and esters. The equilibrium constant for esterification correlates well with the solubility of water in the organic solvent, which in turn shows a good relationship with a function of Guttman's donor number and the electron pair acceptance index number of the solvent. This may be rationalized in terms of the requirements for solvation of water and of the reactants. The catalyst activity, measured as the initial rate of the esterification reaction, is best correlated as a function of both n-octanol-water partition coefficient (log P) and either the electron pair ...
As organizations merge or collaborate closely, an important question is how their existing software assets should be handled. If these previously separate organizations are in the same business domain - they might even have been competitors - it is likely that they have developed similar software systems. To rationalize, these existing software assets should be integrated, in the sense that similar features should be implemented only once. The integration can be achieved in different ways. Success of it involves properly managing challenges such as making as well founded decisions as early as possible, maintaining commitment within the organization, managing the complexities of distributed teams, and synchronizing the integration efforts with concurrent evolution of the existing systems.Th...
Collectively, the organizations participating in the Site Operator Program have over forty years of EV experience and have operated electric vehicles (EVs) for over 600,000 miles, providing the most extensive EV operating and knowledge base in the country. The Site Operator Program is intended to provide financial and technical support and organizational resources to organizations active in the advancement of electric vehicles. Support is provided for the demonstration of vehicles and the test and evaluation of vehicles, components, and batteries. Support is also provided for the management and support of the program for the participating organizations. The Program provides a forum for participants to exchange information among the group, as well as with vehicle and equipment manufacturers and suppliers, and the public. A central data base at the Idaho National Engineering Laboratory provides a repository for-data on the ...
Collectively, the organizations participating in the Site Operator Program have over forty years of EV experience and have operated electric vehicles (EVs) for over 600,000 miles, providing the most extensive EV operating and knowledge base in the country. The Site Operator Program is intended to provide financial and technical support and organizational resources to organizations active in the advancement of electric vehicles. Support is provided for the demonstration of vehicles and the test and evaluation of vehicles, components, and batteries. Support is also provided for the management and support of the program for the participating organizations. The Program provides a forum for participants to exchange information among the group, as well as with vehicle and equipment manufacturers and suppliers, and the public. A central data base at the Idaho National Engineering Laboratory provides a repository for-data on the ...
We present a simple discrete model for the non-linear spatial interaction ofdifferent kinds of ``subpopulations'' composed of identical moving entitieslike particles, bacteria, individuals, etc. The model allows to mimic a varietyof self-organized agglomeration and segregation phenomena. By relating it togame-theoretical ideas, it can be applied not only to attractive and repulsiveinteractions in physical and chemical systems, but also to the much richercombinations of positive and negative interactions found in biological andsocio-economic systems. Apart from investigating symmetric interactions relatedto a continuous increase of the ``overall success'' within the system(``self-optimization''), we will focus on cases, where fluctuations further orinduce self-organization, even though the initial conditions and theinteractions are assumed homogeneous in space (translation invariant).
An hydrazone derivative, 1,2-cyclohexanedione bis-benzoyl-hydrazone (1,2-CHBBH), has been used as a selective reagent for an advanced environmental application consisting of separating the different species of nickel in natural waters by solvent extraction. The effects of pH and reagent concentration on the extraction process were studied, as well as the influence of both organic (humic acids) and inorganic ligands (Cl-). Under natural conditions, organic and inorganic nickel species presented different extraction behaviors, and the variations in extraction yields could be correlated with the concentrations of organic complexes in the samples, allowing the separation of labile and non-labile nickel species in both fresh and marine waters.
Photoelectron resonance capture ionization (PERCI) is a soft and sensitive ionization method, based on the attachment of low-energy (<1 eV) photoelectrons to organic analyte molecules. PERCI has been developed in our laboratory for the real-time analysis of organic particles by mass spectrometry, and is employed here to monitor the heterogeneous reaction of ozone with oleic acid. Simplified identification of the reaction products is possible as a result of the soft nature of PERCI, giving predominantly the [M--H](-) ions. The major particle-phase products are identified as: 1-nonanal, nonanoic acid, 9-oxononanoic acid, and azelaic acid, consistent with proposed mechanisms. New insight into this well-studied heterogeneous reaction is gained as additional minor particle-phase products, consistent with the Criegee mechanism, are readily detected. PMID:15468105
Photoemission-electron-microscopy (PEEM) is introduced as a tool for the characterization of organic electronic devices. PEEM-measurements are used for imaging as well as for spectroscopic analyses by illumination with light of a Hg-lamp (4.9 eV), a D2 lamp (7.3 eV), and with synchrotron radiation for resonant photoelectron spectroscopy. We determine the charge carrier concentration inside the channel region of the organic device and its lateral distribution. From resonant photoelectron spectroscopy (RPES) we deduce the electronic states which are accessible with the Hg and D2 illumination. Photoelectron-spectroscopy at selected areas ({mu}-PES) gives information on the absolute values of surface potentials in lateral resolution. We are able to perform these studies with applied voltages at the source- and drain-electrode.
It is a useful hypothesis to thing of the reaction to protein deprivation as made up of two parts. First there is an initial adaptation involving rapid losses of protein. This is followed by slow continuing depletion. When considering two organ groups, such as the liver and muscle, it appears that the curve of urinary nitrogen excretion reflects the different parts they play in these two phases. The changes in the relative amounts of protein in different organs results in an alteration in the pattern of body protein at the level of the organ, the tissue and the cell. These changes are themselves the result of altered rates of synthesis and breakdown. The questions that must be asked and hopefully will be answered with the help of isotopes, are how these changes are brought about, how they are inter-related and controlled, and what is their significance? This paper contains a discussion of the few results that have been ...
The interfaces between metal electrodes and electroactive organic materials are important for the performance of organic electronic devices. One way of optimizing the anode/organic interface is the insertion of a (sub-)monolayer of molecular acceptors. Here we present an UPS study of new electron acceptor molecules deposited on Au(111), Cu(111) and Ag(111). This study intends to improve the understanding of how the interactions of specific electron withdrawing groups with metal surfaces are correlated with observed modifications of interfacial electron density distribution, work function change ({delta}{phi}), and the energy level alignment. We find that {delta}{phi}, which is the difference between the work function ({phi}) of the clean metal surface and {phi} after formation of a molecular monolayer, is a monotonic function of initial {phi} of the metal. Two different slopes were observed for acceptors with cyano and ...
Many organizations are challenged with the tasks of identifying customer needs and expectations for their products, anticipating future product needs, communicating a future product vision to clients, and designing with today's technology to bring a future vision to successful realization. The design evolution of plant control centres is one aspect of CANDU development that faces such challenges. The Disney Corporation is an example of an organization that has been successful in consistently meeting these challenges for over fifty years; and some of the design practices proven in moviemaking, theme park and resort layout, and vacation experience organization may be helpful and effective when applied in other domains. This paper summarizes the findings from an examination of Disney Corporation design practices, and suggests how some practices could be used to simplify and enhance the design of future CANDU control ...
Lead is a heavy metal which is widely used in paint industry, pigments, dyes, electrical components and electronics, plastic chemicals and in various other things. Since some of the lead salts are soluble in water, lead presents a potential threat to aquatic organisms. Studies dealing with invertebrates include those on mortality, growth and lead uptake in Lymnaea palustris and bioaccumulation of heavy metals in oysters and mussels. Little information exists regarding the effect of lead on the fresh water crustaceans. Hence the present investigation has been undertaken to study the uptake and loss of lead on exposure to subtoxic levels or organic and inorganic lead.
The authors discuss 84 cases of laparoscopic examination of women with primary or secondary infertility. The patients qualified for this examination had undergone at least 26 weeks of conventional treatment with no effect. In 7 cases the reproductive organ was found to be in order, with fallopian tubes fully patent. In 43 cases tubar inpatency was found (using hysterosalpingographic examination). The remaining patients suffered from other reproductive organ disorders. Therefore, the laparoscopic examination made detailed recognition of the causes of infertility possible and thus helped to establish the proper treatment. Additionally, in some cases it enabled the immediate removal of the source of infertility. (author)
Charge transport in disordered organic semiconductors is generally described as thermally activated hopping in a gaussian distribution of localized states. The presence of charge traps is critical to the performance of organic electronic devices, since trapped charge carriers do no longer contribute to the current flow. The trap distribution in the polymer poly(3-hexylthiophene) (P3HT) is investigated by applying the fractional thermally stimulated current technique. Thereby, a low temperatur double-peak distribution has been revealed. One of the peaks is believed to belong to the tail of the intrinsic density of states, whereas the other trap is strongly affected by exposure to oxygen. We discuss the influence of oxygen exposure time on the trap distribution.
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The primary aim of this project is to obtain a basic scientific understanding of electrical transport processes at interfaces that contain an organic electronic material. Because of their processing advantages and the tunability of their electronic properties, organic electronic materials are revolutionizing major technological areas such as information display. We completed an investigation of the fundamental electronic excitation energies in the prototype conjugated polymer MEH-PPV. We completed a combined theoretical/experimental study of the energy relation between charged excitations in a conjugated polymer and the metal at a polymer/metal interface. We developed a theoretical model that explains injection currents at polymer/metal interfaces. We have made electrical measurements on devices ...
An organic inhibitor for acid corrosion inhibition is described. The inhibitor is a condensation product of a mixture of diethyl- and dibutyl-thiourea with hexamethylenetatramine. This condensation product is preferably made by reacting a mixture of diethyl- and dibutyl-thiourea, in a weight ratio of from 1:5 to 5:1, with 0.1 to 1 mole of hexamethylene tetramine per mole of the thiourea mixture, at temperatures of from 100 to 150 C. It is possible to modify this by using other organic thiourea derivatives containing organic radicals (aliphatic or aromatic) having up to 10 carbon atoms, for example, ditoluyl-thiourea, in addition to the mixture of diethyl- and dibutyl-thiourea, but the amount by weight of these other derivatives must not exceed 20% of the diethyl-dibutyl-thiourea mixture. The advantages of the inhibitor are observed mainly when it is used in hydrofluoric acid solutions. 6 claims.
Purpose Video-assisted thoracic surgery (VATS) has recently been adopted for complicated anatomical lung resections. During these thoracoscopic procedures, surgeons view the operative field on a two-dimensional (2-D) video monitor and cannot palpate the organ directly, thus frequently encountering anatomical difficulties. This study aimed to estimate the usefulness of preoperative three-dimensional (3-D) imaging of thoracic organs. Methods We compared the preoperative 64-row three-dimensional multidetector computed tomography (3DMDCT) findings of lung cancer-affected thoracic organs to the operative findings. Results In comparison to the operative findings, the branches of pulmonary arteries, veins, and bronchi were well defined in the 3D-MDCT images of 27 patients. Conclusion 3D-MDCT imag...
Studies continued on organic tracers for use as hydrologic tracers as part of the Yucca Mountain Site Characterization project. This subject report for the quarter 01/01/93 through 03/31/93 discusses the following issues: project organization and responsibilities; quality assurance program; design control; procurement document control; instructions, procedures, and drawings; document control; control of purchased items and services; identification and control of items; control of processes; inspection; test control; control of measuring and test equipment; handling, storage, and shipping; inspection, test, and operating status; control of nonconforming items and conditions; corrective action; quality assurance records; audits; software quality assurance; and scientific investigation.
Individual canine synovial villi were used to establish short-term synovial organ cultures. These villi incorporated /sup 3/H-glucosamine into highly-polymerized /sup 3/H-hyaluronic acid (/sup 3/H-HA), which was the only /sup 3/H-glycosaminoglycan identified in the culture medium. Some /sup 3/H-HA, and larger amounts of other /sup 3/H-glycosaminoglycans, were recovered from cultured tissues. Culture medium /sup 3/H-HA content was proportional to the surface area of cultured villi. Organ cultures of nonvillous synovium were compared with villi; nonvillous cultures synthesized less /sup 3/H-HA per mm2 of their synovial intimal surface than villi. These cultures complement cell culture techniques for in vitro studies of synovial lining cell function.
This study has confirmed large seasonal and daily variations of Rn in soil gas, developed models for the effects of temperature and moisture on air-water Rn partition, inhibited Rn diffusion from wet soil into sparse large air-filled pores and effects of diffusion into bedrock, demonstrated that organic matter is a major host for 226Ra in soils and that organic-bound Ra largely determines the proportion of 222Rn emanated to pore space, shown that in contrast 220Rn is emanated mainly from 224Ra in Fe-oxides, detected significant disequilibrium between 226Ra and 238U in organic matter and in some recent glacial soils, demonstrated by computer models that air convection driven by temperature differences is expected in moderately permeable soils on hillsides.
This study has confirmed large seasonal and daily variations of Rn in soil gas, developed models for the effects of temperature and moisture on air-water Rn partition, inhibited Rn diffusion from wet soil into sparse large air-filled pores and effects of diffusion into bedrock, demonstrated that organic matter is a major host for 226Ra in soils and that organic-bound Ra largely determines the proportion of 222Rn emanated to pore space, shown that in contrast 220Rn is emanated mainly from 224Ra in Fe-oxides, detected significant disequilibrium between 226Ra and 238U in organic matter and in some recent glacial soils, demonstrated by computer models that air convection driven by temperature differences is expected in moderately permeable soils on hillsides.
Organic/metal interface properties are of high interest for the application of molecular (sub)monolayers to modify surface properties. They are applied for, e.g., molecular electronics, chemical sensing, or the tuning of injection barriers in organic electronic devices. We present a joint theoretical and experimental study of F{sub 4}TCNQ adsorbed on Cu(111). The electronic and structural properties were determined by ultraviolet photoelectron spectroscopy (UPS) and X-ray standing wave (XSW) measurements. To better understand the complex process of binding, we modelled the system using density-functional theory. We find forward-donation from the lone pairs of the molecule into metallic states and back-donation from the metal into the LUMO of the molecule. The data on Cu(111) are compared to F4TCNQ on Au(111) and Ag(111) as well as to investigations of pyrenetetraone on various coinage metals.
BackgroundMore than 11 million Americans live with chronic lung disease; in search for an alternative to donor organs, we attempted to regenerate lungs based on perfusion decellularized lung scaffolds that can be transplanted similar to a donor organ. MethodsCadaveric rat lungs were decellularized by detergent perfusion. Resulting scaffolds were mounted in bioreactors and seeded with endothelial and fetal lung cells. Biomimetic organ culture was maintained for 7 days. Resulting bioartificial left lungs were transplanted in orthotopic position after left pneumonectomy in rats. Cadaveric left lung transplants and pneumonectomies served as controls. Blood gas analyses, compliance testing, and fluoroscopies were performed on postoperative days 1, 7, and 14. Lungs were removed for final analysi...
Haemocyanin serves as normal transporter of oxygen in many Arthropods. The oxygen equilibrium curves have been described for the haemocyanins of many Arthropods and Molluscs. Oxygen equilibrium curves of the blood reveal the relationship between the oxygen tension and the percentage saturation of the haemocyanin. The shape of the oxygen equilibrium curves vary in position from sigmoid to hyperbolic in different animals or even undulatory as shown in some chitons. Oxygen equilibrium curves are known to be influenced by pH, temperature and inorganic ions. The effect of environmental pollutants like the heavy metals on the oxygen equilibrium curves of the fresh water crab has not been previously reported. One of the toxic heavy metals with regard to aquatic organisms is lead. Hence the present study was designed to determine the effect of organic and inorganic lead on the oxygen equilibrium curve of the fresh water crab, Barytelphusa guerini.
Young children are at increased risk for valproic acid (VPA) hepatotoxicity. Urinary organic acid profiles, as a surrogate of mitochondrial function, were obtained in children 1.9 to 17.3 years of age (n = 52) who were undergoing treatment with VPA for seizure disorders. Age-matched patients receiving treatment with carbamazepine (CBZ; n = 50) and healthy children not undergoing treatment (n = 22) served as controls. Age-related changes in organic acid profiles were observed in all three groups. Although the untreated and CBZ control groups were indistinguishable from each other with respect to the principal-component analysis (PCA) score plots of the subjects, a distinct boundary was apparent between the VPA and each of the control groups. Interindividual variability was observed in the V...
The Effective Dose Equivalent Concept defined by the International Commission on Radiological Protection in 1977 considers the risk from irradiation including both hereditary and somatic effects. This paper will deal with the definition of a concept for somatic effects only, the somatically significant dose equivalent. This is defined as the dose equivalent which if received by every member of the population, would be expected to produce the same total somatic injury to the population as does the actual dose equivalent received by various individuals. The somatically effective dose equivalent for a particular radiopharmaceutical is the weighted sum of the average dose equivalent to various organs. The dose equivalent to various organs can be derived from an extended MIRD formalism also considering the rest of body excluding the source volumes and the re iden e times in total body and the target organs. Examples are given ...
The Effective Dose Equivalent Concept defined by the International Commission on Radiological Protection in 1977 considers the risk from irradiation including both hereditary and somatic effects. This paper will deal with the definition of a concept for somatic effects only, the somatically significant dose equivalent. This is defined as the dose equivalent which if received by every member of the population, would be expected to produce the same total somatic injury to the population as does the actual dose equivalent received by various individuals. The somatically effective dose equivalent for a particular radiopharmaceutical is the weighted sum of the average dose equivalent to various organs. The dose equivalent to various organs can be derived from an extended MIRD formalism also considering the rest of body excluding the source volumes and the re iden e times in total body and the target organs. Examples are given ...
The atmospheric processing by ozone of peptide-containing mixed particles was investigated as proxies for biogenic and sea spray primary organic aerosol. Reactions were performed in a flow reactor and particle composition was monitored by photoelectron resonance capture ionization aerosol mass spectrometry. Mixed particles containing dipeptides in a saturated organic matrix of stearic and palmitic acids showed no reaction under ozonolysis at exposure levels of 2.5???10?4?atm s O3. However reactions of mixed particles of a dipeptide (Leu-Leu) in an unsaturated matrix (oleic acid) under the same conditions resulted in a rapid loss of the peptide ion signal, as well as the carrier matrix, and appearance of a number of ion signals corresponding to secondary products. High molecular weight imid...
Composting of sawdust and paper mill sludge, using a 'Kneer' process reactor, was studied in an attempt to elaborate upon organic matter transformation during the process and to define parameters to measure the compost maturity level. Temperature, electron paramagnetic resonance data, ash and C, H, N and S contents, and a spectroscopic method using ultraviolet-visible (UV-VIS) for alkaline (pH = 8.5) and solid samples was used to study the maturity of the compost samples. These parameters were measured in 6 humic acids extracted from the compost samples during 29 days. The results of this work show that the 'Kneer' process is efficient in transforming ligno-celulitic residues in a short time (29 days), into an organic fertilizer material with application perspectives (author)
A new strontium metal-organic framework, [Sr2(BTEC)(H2O)4] 2H2O (1) (H4BTEC=benzene-1,2,4,5-tetracarboxylic acid), has been successfully synthesized by mixing the starting reagents. The single-crystal structure analysis showed that compound 1 displayed three-dimensional structures containing inorganic motifs with two-dimensional layers pillar-connected through organic linkers and forming water-coordinated neutral framework. Further studies revealed that compound 1 was insoluble in water and that it emitted strong luminescence at approximately 437nm after dehydration.
The study reports the identification of different organic acids that are formed during the pyrohydrolysis of mixed carbide of uranium and plutonium using ion chromatography (IC). The identification of organic acids present in the pyrohydrolysis distillate is required to carry out interference free analysis of Cl and F. The study describes three stage isocratic separations with NaOH eluents having concentrations 2 mM, 10 mM and 50 mM respectively in order to separate and identify both aliphatic and aromatic acids. The present investigation identified formic, acetic, propionic, butyric, tartaric and oxalic acids in the distillate, however, aromatic acids could not be identified. (author)
We report here a many-year study of the qualitative and quantitative content of flavonoids in the reproductive organs of the showy tick trefoil (Desmodium canadense (L.) DC., Fabaceae) - stems, leaves, buds, inflorescences,pods, and seeds - collected at different phases of growth at the Department of Medicinal Plants, Kaunas Botanical Garden, Vytautas Magnus University. HPLC studies identified 15 aglycone and glycoside flavonoids: apigenin, apigenin-7-O-glycoside, luteolin, rutin, vicenin-2, vitexin, isovitexin, vitexin rhamnoside, orientin, homoorientin, quercetrin, quercetin, hyperoside, astralagin, and kaempferol. The largest quantities of flavonoids in the vegetative organs from year 2 to year 4 of plant growth were present in the leaves (2.64% and 2.61% at budding and flowering in the...
The World Health Organization (WHO) estimates that as many as 80% of the world's more than six billion people rely primarily on animal and plant-based medicines. The healing of human ailments by using...Full Text Available
We report a whole-genome shotgun assembly (called WGSA) of the human genome generated at Celera in 2001. The Celera-generated shotgun data set consisted of 27 million sequencing reads organized in pairs...Full Text Available
Autophagy is a ubiquitous catabolic process that ensures organism’s well-being by sequestering a wide array of undesired intracellular constituents into double-membrane vesicles termed...Full Text Available
Ecological investigations were made of habitats containing natural populations of the snail Oncomelania hupensis quadrasi and of habitats free from the snail in the island of Leyte,...Full Text Available
We recently discovered that human activity possesses a complex temporal organization characterized by scale-invariant/self-similar fluctuations from seconds to ~4 hour—statistical properties...Full Text Available
Assessments of drinking water safety rely on the assumption that ingestion represents the principal route of exposure. A review of the experimental literature revealed that skin penetration rates for...Full Text Available
We tried to apply a quartz crystal as a sensor by using the resonant frequency and the resistance properties of quartz crystals. Four kinds of fatty acids that have the same head groups were coated on the surfaces of the quartz crystals, and the shift of the resonant frequency and the resistance were observed based on the lengths of the tail groups. Myristic acid (C{sub 14}), palmitic acid (C{sub 16}), stearic acid (C{sub 18}), and arachidic acid (C{sub 20}) were deposited on the surfaces of quartz crystals by using the Langmuir-Blodgett (LB) method. As a result, the resonant frequency change was more sensitive to high molecular-weight fatty acids than to low molecular-weight ones. We also observed the effect of temperature on stearic acid LB films, and the response properties of quartz crystals coated with stearic-acid LB films to organic gases were investigated. As a result, the sensitivity of quartz crystals to organic gases was higher for ...
The target of rapamycin (TOR) pathway regulates cell growth and aging in various organisms. In Saccharomyces cerevisiae, silent information regulator 2 (Sir2) modulates cellular senescence. Moreover,...Full Text Available
Many healthcare organizations utilize network "firewalls" to protect their networks from being accessed by unauthorized external entities. These same firewalls are also often configured to deny access...Full Text Available
The world's oceans contain a complex mixture of micro-organisms that are for the most part, uncharacterized both genetically and biochemically. We report here a metagenomic study of the marine planktonic...Full Text Available
We have developed a method to extract and separate phytochelatins (PCs)—metal(loid) complexes using parallel metal(loid)-specific (inductively coupled plasma-mass spectrometry) and organic-specific...Full Text Available
In pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions, the Petroleum Technology Transfer Council (PTTC) functions as a cohesive national organization that implements industry's directives through active regional programs. The role of the national headquarters (HQ) organization includes planning and managing the PTTC program, conducting nation-wide technology transfer activities, and implementing a comprehensive communications effort. PTTC relies on 10 Regional Lead Organizations (RLOs) as its main program delivery mechanism to industry. Through its regions, PTTC connects with independent oil and gas producers--through technology workshops, resources centers, websites, newsletters, and other outreach efforts. The organization effectively combines federal, state, and industry funding to achieve important goals for all of these ...
Lectin is a generic name of sugar binding protein in living organisms. With an objective to clarify physiological functions of lectin in marine invertebrates and utilize it as a useful material in the bio-chemical industry, studies were carried out on the chemical structure, distribution in living organisms and structural changes of lectin. Lectin is involved with such physiological actions as immunity reactions, generation and differentiation, Ca fixation and symbiosis. Lectin is one of the main components of lymph fluid in shellfish and crustacean, and is a multi-functional polymer that is related with foreign substance recognition, Ca transport, and shell formation. Lectin of a certain kind shows strong actions to accelerate cell division. Organs and cells were cultivated for lectin producing organs and lectin producing cells to verify the production thereof. Elucidation was attempted in a molecular ...
This annual review focuses on invertebrate model organisms, which continue to yield fundamental new insights into mechanisms of aging. This year, the budding yeast has been used to understand how asymmetrical...Full Text Available
Organisms ranging from bacteria and corals to plants and vertebrates can form intransitive competitive networks, in which coexistence can be maintained because no one species or genotype is superior...Full Text Available
Serratia odorifera biogroup 1 was isolated from the blood and urine of an alcoholic male with cirrhosis and signs of septic shock. The organism is rarely reported to occur in clinical specimens. This...Full Text Available
BackgroundGenomes store information for building and maintaining organisms. Complete sequencing of many genomes provides the opportunity to study and compare global information properties...Full Text Available
This report of an interview with T. Watamori, Chairman of the Board of Directors of the New Energy Development Organization (NEDO), Japan outlines the general activities of NEDO, and then gives emphasis to the prospects of the liquefaction of brown coal from Australia. (In Japanese)
From view on Organization Behavior theory, the concept, development and affecting factors of safety culture are introduced. The focuses are on the establishment, development and management practice for safety culture at Daya Bay NPP. A strong safety culture, also demonstrated, has contributed greatly to improving performance at Daya Bay
The planned spallation source can be of considerable significance for biomedical basic research and for clinically relevant diagnostic and therapeutic applications. The following gives a brief description and explanations for its possible use in clinical medicine: I. Treatment of Malignant Tumors II. Production of Isotopes for Biochemical Investigations in Living Organisms for Diagnostic Purposes.
The intracellular bioavailability of lead (Pb) at low dosage levels in major target organs such as the kidney and brain appears to be largely determined by complexation with a group of low molecular...Full Text Available
A recent EPA-sponsored study of sediment and seafood contamination in Quincy Bay revealed elevated levels of several complex organic pollutants frequently of concern in human health assessments. A seafood...Full Text Available
CSIRO is Australia's one and only federal government research organization. After a description of Australian coal resources and coal-related research, accounts are given of the selection of research topics at CSIRO and of the coal utilization and coal liquefaction research which is being undertaken.
Gene expression is a unique way of characterizing how cells and organisms adapt to changes in the external environment. The measurements of gene expression levels upon exposure to a chemical can be...Full Text Available
Purpose: calculation of conversion coefficients for the reconstruction of organ doses from entrance doses for abdomen radiographs of 0, 1, 5, 10, 15, and 30-year-old patients in conventional pediatric radiology for the radiographic settings recommended by the German and European guidelines for quality management in diagnostic radiology. Materials und method: using the commercially available personal computer program PCXMC developed by the Finnish Center for Radiation and Nuclear Safety (Saeteilyturvakeskus STUK), conversion coefficients for conventional abdomen radiographs were calculated performing Monte Carlo simulations in mathematical hermaphrodite phantom models describing patients of different ages. The possible clinical variation of beam collimation was taken into consideration by defining optimal and suboptimal radiation fields on the phantoms' surfaces. Results: conversion coefficients for the reconstruction of organ does in ...
Stem cells are expected to play a key role in the development and maintenance of organisms, and hold great therapeutic promises. However, a number of questions must be answered to achieve an...Full Text Available
A patient’s electronic medical record contains a large amount of unstructured textual information. As patient records become increasingly dense owing to an aging population and increased occurrence...Full Text Available
This report will be revised upon completion of current testing investigating the radiolytic stability of additional energetic materials and the analysis of tank farm samples for volatile and semi-volatile organic compounds.
This chapter summarizes research progress in development of phytoremediation technologies. Some soils have become contaminated by trace elements enough to kill plants, inhibit soil organisms, and/or threaten wildlife, humans or the environment. Traditional remediation by dig and haul methods are v...
A strain of Chromobacterium violaceum has been isolated which produces bacteriophage tail-like particles in high numbers. The extracellular morphology and the intracellular arrangement...Full Text Available
Noncoding RNAs play important roles in various aspects of gene regulation. We have identified 7SK RNA to be enriched in nuclear speckles or interchromatin granule clusters (IGCs), a subnuclear domain...Full Text Available
for an Air Force Manufacturing technology program whose aim is the establishment of organic matrix ...... display considerations for advanced energy/flight management sys- ...... Future System - The Roadmap of the System of the Future - ...... data storage units, pilot's guidance indicators, and a quick look ...
The pharmacokinetic parameters of amikacin and ceftazidime were assessed in four patients undergoing hemofiltration for septic shock. The parameters were assessed during hemofiltration and in the interim...Full Text Available
For the risk estimate of fatal malignancies, an effective dose was proposed on the basis of the assumption that the risk should be equal whether the whole body irradiated uniformly or whether there is non-uniform irradiation. The effective dose was defined by the product of organ or tissue doses and a weighting factor representing the proportion of risk factor for a fatal malignancy resulting from organ or tissue irradiation to the total malignant factor. The risk of malignancies can be derived by multiplying the malignant significant factor by the product of the risk factor and the effective dose. For the genetic risk, a significant factor was a relative child expectancy and organ or tissue doses were gonad doses. And, for the leukemogenic risk, a significant factor was the leukemia significant factor and organ or tissue dose was mean bone marrow dose. The present method makes it easy to estimate the ...
Sirtuins are highly conserved NAD+-dependent protein deacetylases and/or ADP-ribosyltransferases that can extend the lifespan of several lower model organisms including yeast, worms and flies....Full Text Available
The mammalian circadian system consists of a central oscillator in the suprachiasmatic nucleus of the hypothalamus, which coordinates peripheral clocks in organs throughout the body. Although circadian...Full Text Available
All molybdenum enzymes except nitrogenase contain a common molybdenum cofactor, whose organic moiety is a novel pterin called molybdopterin (MPT). To assist in elucidating the biosynthetic pathway of...Full Text Available
BackgroundRecent data show aberrant and altered expression of regulatory noncoding micro (mi) RNAs in prostate cancer (PCa). A large number of miRNAs are encoded in organized intronic...Full Text Available
In the information age, information utilities like libraries are as sensitive to the stresses of change as any other organization. This article is a case study of a small, specialized medical library...Full Text Available
BackgroundAlthough the World Health Organization had recommended that every child be vaccinated for Hepatitis B by the early 1980s, large multinational pharmaceutical companies held...Full Text Available
Recent research has shown that biologically inspired approaches to materials synthesis and self-assembly, hold promise of unprecedented atomic level control of structure and interfaces. In particular, the use of organic molecules to control the production of inorganic technological materials has the potential for controlling grain structure to enhance material strength; controlling facet expression for enhanced catalytic activity; and controlling the shape of nanostructured materials to optimize optical, electrical and magnetic properties. In this work, we use organic molecules to modify silver crystal shapes towards understanding the metal-organic interactions that lead to nanoparticle shape control. Using in situ electrochemical AFM (EC-AFM) as an in situ probe, we study the influence of a cationic surfactant cetyltrimethylamminobromide (CTAB) on Ag growth during electrochemical deposition on Ag(100). The results show ...
We report here on a case of localized lymphoid hyperplasia of the pancreas in a 70-year-old man which manifested as double lesions (uncinate process and tail) in the organ. The lesions were incidentally...Full Text Available
BackgroundIn recent years, the sea anemone Nematostella vectensis has emerged as a critical model organism for comparative genomics and developmental biology. Although...Full Text Available
Foreward: Preface; Introduction; The natural science of global climate change; Land and water use; Coastal zones and oceans; Energy and industry; Energy and social systems; Technological change; and Sponsoring organizations, International Advisory Board, and project participants.
BackgroundPolyadenylation of RNA has a decisive influence on RNA stability. Depending on the organisms or subcellular compartment, it either enhances transcript stability or targets...Full Text Available
Hydrothermal vent mussels belonging to the genus Bathymodiolus are distributed worldwide and dominate communities at shallow Atlantic hydrothermal sites. While organisms inhabiting...Full Text Available
The genetic architecture of complex traits underlying physiology and disease in most organisms remains elusive. We still know little about the number of genes that underlie these traits, the magnitude...Full Text Available
BackgroundA strong association between stress resistance and longevity in multicellular organisms has been established as many mutations that extend lifespan also show increased...Full Text Available
Francisella tularensis requires iron (Fe) for growth, but the biologic sources of Fe for this organism are largely unknown. We found that Francisella sp. growing in...Full Text Available
Summarizing the three main reasons why customized programs are commissioned, this book explains and explores the key aspects of successful development programs, with views from corporate sponsors, participants, faculty contributors and case studies of customised programs commissioned by 6 organizations
All eukaryotes require mitochondria for survival and growth. The origin of mitochondria can be traced down to a single endosymbiotic event between two probably prokaryotic organisms. Subsequent evolution...Full Text Available
Scaling relations among plant traits are both cause and consequence of processes at organ-to-ecosystem scales. The relationship between leaf nitrogen and phosphorus is of particular interest, as both...Full Text Available
Using pharmacological and chromatographic techniques, it was shown that acetylcholine was present in all organs of both light- and dark-grown mung bean seedings (Phaseolus aureus)....Full Text Available
BackgroundEpidemiologic studies associate lung cancer in non-smoking Chinese women with Chinese-style wok cooking. Our goal was to quantify carcinogen and toxicant...Full Text Available
Soybean (Glycine max) is a paleopolyploid whose genome has gone through at least two rounds of polyploidy and subsequent diploidization events. Several studies have investigated the...Full Text Available
In virtually all organisms, life expectancy is profoundly affected by caloric intake. For example, dietary restriction (DR; a feeding regimen of fewer calories compared to the ad libitum level without...Full Text Available
Ammonium sulfate is produced from spent sulfuric acid from the production of alcohols. Certain mineral and organic impurities exist in the sulfuric acid that impair the quality of the ammonium sulfate. A detailed method for the chemical analysis for the impurities is presented.
For the purpose of risk estimates from radiation carcinogenesis including leukemogenesis and radiation genetic effects, the biological significant dose is not the tissue kerma in air but the absorbed dose in organ or tissue with respect to carcinogenic and leukemogenic effects or genetic effects. In order to estimate organ or tissue dose from the tissue kerma in air, a ratio of the organ or tissue dose to the tissue kerma in air for survivors in Hiroshima and Nagasaki was calculated with the aid of the Snyder's mathematical phantoms constructed so as to simulate the body shape of survivors aged 5, 10 years old and adult at the time of atomic bomb detonations. The ratios were corrected for the angular distribution of atomic bomb radiations, assuming an anisotropic angular distribution for the survivors exposed to the atomic bombs in open air and the isotropic distribution for the survivors incide a Japanese house or other ...
Examples are used to demonstrate that a shift in the point of emphasis is necessary with regard to radiation hazard in medicinal X-ray diagnosis. The parameters employed in this study to calculate somatic dose (SD) and somatically significant dose (SSD) m...
Polycyclic aromatic hydrocarbons (PAH`s) are ubiquitous hydrophobic organic pollutants in the marine environment. Many of the PAM`s are classified as possible carcinogens or mutagens, therefore they are of considerable concern to human and environmental health. The highest concentrations are found in coastal regions due to anthropogenic activities including oil spills, tanker operations, incomplete fossil fuel combustion and runoff. The sources and distribution of PAM`s in sediments are fairly well known, while the fate and transport of PAH`s in the marine environment are less known. Desorption is an important factor influencing the fate and transport of hydrophobic molecules at the seawater/sediment interface. The desorption of PAH`s from contaminated marine sediments to the water column/pore water affects the availability of the pollutant to biota. The sorption of PAH`s is determined in part by the organic carbon content of the sediments. The ...
The potential for oxidation of ammonia in anoxic marine sediments exists through anaerobic oxidation by Nitrosomonas-like organisms, utilizing nitrogen dioxide, coupling of nitrification,...Full Text Available
This article addresses the problem of how to ensure consistency in messages communicating public health recommendations on environmental health and on child health. The World Health Organization states...Full Text Available
The F1F0 ATPase of Vibrio alginolyticus was cloned from a chromosomal lambda library. The unc operon, which contains the structural genes for the ATPase, was sequenced and shown to have a gene organization...Full Text Available
Organisms belonging to the genus Streptomyces produce numerous important secondary metabolites and undergo a sophisticated morphological differentiation program. In many instances these...Full Text Available
Fish living in contaminated environments accumulate toxic chemicals in their tissues. Biomarkers are needed to identify the resulting health effects, particularly focusing on early changes at a subcellular...Full Text Available
BackgroundThe aim of this paper is to discuss the controversial origins of petals from tepals or stamens and the links between the morphological expression of petals and floral organ...Full Text Available
BackgroundNormal and pathological processes entail the production of oxidative substances that can damage biological molecules and harm physiological functions. Organisms have evolved...Full Text Available
To study the occurrence and distribution of various strains of Haemophilus parasuis in southern Ontario swine, organisms isolated from healthy swine, from specific pathogen-free and conventional herds,...Full Text Available
Evolutionary theory holds that aging is a consequence of the declining force of natural selection with age. We discuss here the evidence that among the causes of aging in complex multicellular organisms, such as mammals, is the antagonistically pleiotropic effects of the cellular responses that protect the organism from cancer. Cancer is relatively rare in young mammals, owing in large measure to the activity of tumor suppressor mechanisms. These mechanisms either protect the genome from damage and/or mutations, or they elicit cellular responses--apoptosis or senescence--that eliminate or prevent the proliferation of somatic cells at risk for neoplastic transformation.We focus here on the senescence response, reviewing its causes, regulation and effects. In addition, we describe recent data that support the idea that both senescence and apoptosis may indeed be the double-edged swords predicted by the evolutionary hypothesis of antagonistic ...
Recent research at the laboratory scale by a number of organizations in different countries has shown that with the use of particular types of solvents it is possible to achieve almost complete conversion of coal to liquid products under relatively mild process conditions. This work is reviewed and the conclusions to be drawn from it are summarized.
BackgroundWe have recently introduced a predictive framework for studying gene transcriptional regulation in simpler organisms using a novel supervised learning algorithm called...Full Text Available
In this era of complete genomes, our knowledge of neuroanatomical circuitry remains surprisingly sparse. Such knowledge is critical, however, for both basic and clinical research into brain function....Full Text Available
Several nematode species have now attained ‘model organism’ status, yet there remain many niches in basic biological inquiry for which nematodes would be ideal model systems of study....Full Text Available
The pattern of biodegradation and the chemical changes occurring in the macromolecular fraction of domestic sludge during autothermal thermophilic aerobic digestion (ATAD) was monitored and characterised...Full Text Available