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Sample records for nuclear-quadruple-resonance nqr study

  1. Temperature and baric dependence of nuclear quadruple resonance spectra in indium and gallium monoselenides

    NASA Astrophysics Data System (ADS)

    Khandozhko, Victor; Raranskii, Nikolai; Balazjuk, Vitaly; Samila, Andriy; Kovalyuk, Zahar

    2013-12-01

    Pulsed radiospectroscopy method has been used to study nuclear quadruple resonance (NQR) spectra of 69Ga and 115In isotopes in the layered semiconductors GaSe and InSe. It has been found that in GaSe and InSe there is a considerable temperature dependence of NQR frequency which in the temperature range of 250 to 390 K is practically linear with conversion slope 1.54 kHz/degree for 69Ga and 2.35 kHz/degree for 115In. In the same crystals the effect of uniaxial pressure on NQR spectra applied along the optical axis с up to the values of 500 kg/сm2 has been studied. A strong attenuation of NQR spectra intensity with increase in pressure on layered crystal package has been established. The unvaried multiplicity of resonance spectra indicates the absence of structural transformations in these layered crystals over the investigated range of temperatures and pressures.

  2. NQR studies on 2,5-dichlorophenol

    NASA Astrophysics Data System (ADS)

    Kasturi, Alapati; Venkatacharyulu, P.; Premaswarup, D.

    1990-11-01

    Nuclear quadrupole resonance (NQR) Zeeman effect studies were carried out on cylindrical single crystals of 2,5-dichlorophenol, using the two 35Cl-NQR frequencies. A self-quenched superregenerative NQR spectrometer was used, and the spectra were analysed ot obtain information on the nature of the crystalline unit cell. An analysis of the experimental data reveals that: (1) the results are in good agreement with the structural reports of Bavoux and Perrin; (2) the crystal unequivocally belongs to the monoclinic system; (3) there are two crystallographically equivalent but physically inequivalent directions for the principal field gradient axes for both the low- and high-frequency resonance lines; (4) as the number of physically inequivalent directions for each of the two resonance lines is two, the minimum number of molecules per unit cell is two; (5) the b axis (90°,90°) is identified as the symmetry axis; (6) the growth axis is slightly inclined to the c axis; (7) the asymmetry parameters obtained for the loci corresponding to the low-frequency line, which is hydrogen bonded, are greater than those for the high-frequency line, which is nonhydrogen bonded; (8) the double-bond character is greater for the hydrogen-bonded chlorine than for the non-hydrogen-bonded chlorine; (9) the ratios of the various bond characters estimated for both the low- and high-frequency resonance lines are 69:24:7 and 74:24:2.

  3. NMR and NQR study of the thermodynamically stable quasicrystals

    SciTech Connect

    Shastri, A.

    1995-02-10

    {sup 27}Al and {sup 61,65}Cu NMR measurements are reported for powder samples of stable AlCuFe and AlCuRu icosahedral quasicrystals and their crystalline approximants, and for a AlPdMn single grain quasicrystal. Furthermore, {sup 27}Al NQR spectra at 4.2 K have been observed in the AlCuFe and AlCuRu samples. From the quadrupole perturbed NMR spectra at different magnetic fields, and from the zero field NQR spectra, a wide distribution of local electric field gradient (EFG) tensor components and principal axis system orientations was found at the Al site. A model EFG calculation based on a 1/1 AlCuFe approximant was successful in explaining the observed NQR spectra. It is concluded that the average local gradient is largely determined by the p-electron wave function at the Al site, while the width of the distribution is due to the lattice contribution to the EFG. Comparison of {sup 63}Cu NMR with {sup 27}Al NMR shows that the EFG distribution at the two sites is similar, but that the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more s-type wave function of the conduction electrons.

  4. Methyl quantum tunneling and nitrogen-14 NQR NMR studies using a SQUID magnetic resonance spectrometer

    SciTech Connect

    Black, B.E. |

    1993-07-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) techniques have been very successful in obtaining molecular conformation and dynamics information. Unfortunately, standard NMR and NQR spectrometers are unable to adequately detect resonances below a few megahertz due to the frequency dependent sensitivity of their Faraday coil detectors. For this reason a new spectrometer with a dc SQUID (Superconducting Quantum Interference Device) detector, which has no such frequency dependence, has been developed. Previously, this spectrometer was used to observe {sup 11}B and {sup 27}Al NQR resonances. The scope of this study was increased to include {sup 23}Na, {sup 51}V, and {sup 55}Mn NQR transitions. Also, a technique was presented to observe {sup 14}N NQR resonances through cross relaxation of the nitrogen polarization to adjacent proton spins. When the proton Zeeman splitting matches one nitrogen quadrupoler transition the remaining two {sup 14}N transitions can be detected by sweeping a saturating rf field through resonance. Additionally, simultaneous excitation of two nitrogen resonances provides signal enhancement which helps to connect transitions from the same site. In this way, nitrogen-14 resonances were observed in several amino acids and polypeptides. This spectrometer has also been useful in the direct detection of methyl quantum tunneling splittings at 4.2 K. Tunneling, frequencies of a homologous series of carboxylic acids were measured and for solids with equivalent crystal structures, an exponential correlation between the tunneling frequency and the enthalpy of fusion is observed. This correlation provides information about the contribution of intermolecular interactions to the energy barrier for methyl rotation.

  5. NQR application to the study of hydrogen dynamics in hydrogen-bonded molecular dimers

    NASA Astrophysics Data System (ADS)

    Asaji, Tetsuo

    2016-12-01

    The temperature dependences of 1H NMR as well as 35Cl NQR spin-lattice relaxation times T 1 were investigated in order to study the hydrogen transfer dynamics in carboxylic acid dimers in 3,5-dichloro- and 2,6-dichlorobenzoic acids. The asymmetry energy A/ k B and the activation energy V/ k B for the hydrogen transfer were estimated to be 240 K and 900 K, and 840 K and 2500 K, respectively, for these compounds. In spite of a large asymmetric potential the quantum nature of hydrogen transfer is recognized in the slope of the temperature dependence of T 1 on the low-temperature side of the T 1 minimum. The NQR T 1 measurements was revealed to be a good probe for the hydrogen transfer dynamics.

  6. Single crystal zeeman effect studies on 35Cl NQR lines of 2,6-dichlorophenol

    NASA Astrophysics Data System (ADS)

    Prasad, N. V. L. N.; Venkatacharyulu, P.; Premaswarup, D.

    1987-10-01

    Zeeman effect studies on the two 35Cl NQR lines in cylindrical single crystals of 2,6-dichlorophenol were carried out using a self-quenched super-regenerative NQR spectrometer to obtain information on the nature of the crystalline unit cell and the effect of hydrogen bonding on the electric field gradient tensor. Analysis of the experimental data reveals: (1) the results are in good agreement with those reported from X-ray studies; (2) the crystal is unequivocally identified as belonging to the orthorhombic system; (3) there are two crystallographically equivalent and four physically nonequivalent directions for the principal field gradients for both the low and high frequency resonance lines; (4) the directions of the crystalline a, b, c axes are uniquely identified as (90°, 0°), (0°, -), and (90°, 90°); (5) the b-axis is identified as the growth axis; (6) there are a minimum of four molecules per unit cell, the four molecules lie in different planes, which are, however, connected by symmetry operations; (7)_there exists a weak intramolecular hydrogen bonding in the crystal; (8) the asymmetry parameters for the loci corresponding to the low frequency resonance line, which is affected by hydrogen bonding, are less than the asymmetry parameters of the loci corresponding to the high frequency resonance line, which is not affected by hydrogen bonding; (9) the single bond and ionic bond characters for the hish frequency line are less than that of the low frequency line, while the double bond character for the low frequency line is less than that of the high frequency line and (10) the small deviation between the single bond and double bond characters of the two resonance lines is attributed to the existence of weak hydrogen bonding in the crystal.

  7. Solid-state NMR/NQR and first-principles study of two niobium halide cluster compounds.

    PubMed

    Perić, Berislav; Gautier, Régis; Pickard, Chris J; Bosiočić, Marko; Grbić, Mihael S; Požek, Miroslav

    2014-01-01

    Two hexanuclear niobium halide cluster compounds with a [Nb6X12](2+) (X=Cl, Br) diamagnetic cluster core, have been studied by a combination of experimental solid-state NMR/NQR techniques and PAW/GIPAW calculations. For niobium sites the NMR parameters were determined by using variable Bo field static broadband NMR measurements and additional NQR measurements. It was found that they possess large positive chemical shifts, contrary to majority of niobium compounds studied so far by solid-state NMR, but in accordance with chemical shifts of (95)Mo nuclei in structurally related compounds containing [Mo6Br8](4+) cluster cores. Experimentally determined δiso((93)Nb) values are in the range from 2,400 to 3,000 ppm. A detailed analysis of geometrical relations between computed electric field gradient (EFG) and chemical shift (CS) tensors with respect to structural features of cluster units was carried out. These tensors on niobium sites are almost axially symmetric with parallel orientation of the largest EFG and the smallest CS principal axes (Vzz and δ33) coinciding with the molecular four-fold axis of the [Nb6X12](2+) unit. Bridging halogen sites are characterized by large asymmetry of EFG and CS tensors, the largest EFG principal axis (Vzz) is perpendicular to the X-Nb bonds, while intermediate EFG principal axis (Vyy) and the largest CS principal axis (δ11) are oriented in the radial direction with respect to the center of the cluster unit. For more symmetrical bromide compound the PAW predictions for EFG parameters are in better correspondence with the NMR/NQR measurements than in the less symmetrical chlorine compound. Theoretically predicted NMR parameters of bridging halogen sites were checked by (79/81)Br NQR and (35)Cl solid-state NMR measurements. PMID:24581866

  8. Ab initio DFT study of bisphosphonate derivatives as a drug for inhibition of cancer: NMR and NQR parameters.

    PubMed

    Aghabozorg, Hussein; Sohrabi, Beheshteh; Mashkouri, Sara; Aghabozorg, Hamid Reza

    2012-03-01

    DFT computations were carried out to characterize the (17)Oand (2)H electric field gradient, EFG, in various bisphosphonate derivatives. The computations were performed at the B3LYP level with 6-311++G (d,P) standard basis set. Calculated EFG tensors were used to determine the (17)O and (2)H nuclear quadrupole coupling constant, χ and asymmetry parameter, η. For better understanding of the bonding and electronic structure of bisphosphonates, isotropic and anisotropic NMR chemical shieldings were calculated for the (13)C, (17)O and (31)P nuclei using GIAO method for the optimized structure of intermediate bisphosphonates at B3LYP level of theory using 6-311++G (d, p) basis set. The results showed that various substituents have a strong effect on the nuclear quadrupole resonance (NQR) parameters (χ, η) of (17)O in contrast with (2)H NQR parameters. The NMR and NQR parameters were studied in order to find the correlation between electronic structure and the activity of the desired bisphosphonates. In addition, the effect of substitutions on the bisphosphonates polarity was investigated. Molecular polarity was determined via the DFT calculated dipole moment vectors and the results showed that substitution of bromine atom on the ring would increase the activity of bisphosphonates. PMID:21633790

  9. Electron density distribution in cladribine (2-chloro-2‧-deoxyadenosine) - A drug against leukemia and multiple sclerosis - Studied by multinuclear NQR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Latosińska, J. N.; Latosińska, M.; Seliger, J.; Žagar, V.; Kazimierczuk, Z.

    2009-07-01

    2-Chloro-2'-deoxyadenosine (Cladribine) chemotherapeutic drug has been studied experimentally in solid state by 35Cl NQR and NMR-NQR double resonance and theoretically by the Density Functional Theory. Fifteen resonance frequencies on 14N have been detected and assigned to particular nitrogen sites in the 2-CdA molecule. The effects of tautomerism, regioisomerism, conformations and molecular aggregations, related to intermolecular hydrogen bond formation, on the NQR parameters have been analysed within the DFT and AIM ( Atoms in Molecules) formalism. The properties of the whole molecule, the so-called global reactivity descriptors, have been calculated for a comparison of both syn and anti conformations of 2-CdA molecule to check the effect of crystal packing on molecular conformation.

  10. Polymorphism and disorder in natural active ingredients. Low and high-temperature phases of anhydrous caffeine: Spectroscopic ((1)H-(14)N NMR-NQR/(14)N NQR) and solid-state computational modelling (DFT/QTAIM/RDS) study.

    PubMed

    Seliger, Janez; Žagar, Veselko; Apih, Tomaž; Gregorovič, Alan; Latosińska, Magdalena; Olejniczak, Grzegorz Andrzej; Latosińska, Jolanta Natalia

    2016-03-31

    The polymorphism of anhydrous caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) has been studied by (1)H-(14)N NMR-NQR (Nuclear Magnetic Resonance-Nuclear Quadrupole Resonance) double resonance and pure (14)N NQR (Nuclear Quadrupole Resonance) followed by computational modelling (Density Functional Theory, supplemented Quantum Theory of Atoms in Molecules with Reduced Density Gradient) in solid state. For two stable (phase II, form β) and metastable (phase I, form α) polymorphs the complete NQR spectra consisting of 12 lines were recorded. The assignment of signals detected in experiment to particular nitrogen sites was verified with the help of DFT. The shifts of the NQR frequencies, quadrupole coupling constants and asymmetry parameters at each nitrogen site due to polymorphic transition were evaluated. The strongest shifts were observed at N(3) site, while the smallest at N(9) site. The commercial pharmaceutical sample was found to contain approximately 20-25% of phase I and 75-80% of phase II. The orientational disorder in phase II with a local molecular arrangement mimics that in phase I. Substantial differences in the intermolecular interaction phases I and II of caffeine were analysed using computational (DFT/QTAIM/RDS) approach. The analysis of local environment of each nitrogen nucleus permitted drawing some conclusions on the topology of interactions in both polymorphs. For the most stable orientations in phase I and phase II the maps of the principal component qz of EFG tensor and its asymmetry parameter at each point of the molecular system were calculated and visualized. The relevant maps calculated for both phases I and II indicates small variation in electrostatic potential upon phase change. Small differences between packings in phases slightly disturb the neighbourhood of the N(1) and N(7) nitrogens, thus are meaningless from the biological point of view. The composition of two phases in pharmaceutical material

  11. 35C NQR studies in 2,4,6-,2,3,6-, and 2,3,4-trichloro anisoles

    NASA Astrophysics Data System (ADS)

    Rukmani, K.; Ramakrishna, J.

    1985-02-01

    The chlorine-35 NQR frequencies and their temperature variation in 2,4,6-, 2,3,6- and 2,3,4-trichloro anisoles have been studied and compared with the corresponding chlorophenols with a view to studying the effect of hydrogen bonding. The observed frequencies have been assigned to the various chlorines with the help of the additive model of the substituent effect. The temperature dependence has been analysed in terms of the Bayer—Kushida—Brown models. The torsional frequencies and their temperature dependence have been calculated numerically under a two mode approximation. A comparison of the trichloro anisoles with the corresponding trichloro phenols has shown that the resonance frequency decreases due to hydrogen bonding while the torsional frequencies are not affected.

  12. Studies of the electronic structure and biological activity of chosen 1,4-benzodiazepines by 35Cl NQR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Bronisz, K.; Ostafin, M.; Poleshchuk, O. Kh.; Mielcarek, J.; Nogaj, B.

    2006-11-01

    Selected derivatives of 1,4-benzodiazepine: lorazepam, lormetazepam, oxazepam and temazepam, used as active substances in anxiolytic drugs, have been studied by 35Cl NQR method in order to find the correlation between electronic structure and biological activity. The 35Cl NQR resonance frequencies ( νQ) measured at 77 K have been correlated with the following parameters characterising their biological activity: biological half-life period ( t0.5), affinity to benzodiazepine receptor (IC 50) and mean dose equivalent. The results of experimental study of some benzodiazepine derivatives by nuclear quadrupole resonance of 35Cl nuclei are compared with theoretical results based on DFT calculations which were carried out by means of Gaussian'98 W software.

  13. Studies of Ga NMR and NQR in SrGa4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Higa, N.; Nakamura, S.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; Ōnuki, Y.; Harima, H.

    2015-04-01

    In order to microscopically investigate the properties in SrGa4, the Ga NMR measurements of a powder sample were carried out. The Ga NMR spectra corresponding to Ga(I) and Ga(II) sites are obtained. The NMR spectra of 69&71Ga (a nuclear spin I = 3/2) in the powder sample of SrGa4 do not take a typical powder pattern caused by the NQR interaction, but take the spectra consisting of three well resolved resonance-lines, which indicates that the nonuniform distribution of crystal orientation in the powder sample occurs because of the magnetic anisotropy. From the analysis of the Ga NMR spectrum, it is found that the ab-plane of the crystal is parallel to the external magnetic field, which would be attributed to the anisotropy of the magnetic susceptibility with the easy axis parallel to the ab-plane. This result is also confirmed by the 69Ga NQR in SrGa4. The Knight shifts of the 69Ga(I) and 69Ga(II) shift slightly to the negative side with decreasing temperature due to the core polarization of the d-electrons. The values of the Knight shift of the 69Ga(I) and 69Ga(II) are 0.01 and -0.11 % at 4.2 K, and 0.09 and -0.08 % at 300 K, respectively. The values of the 1/ T 1 T of the NMR of both 69Ga(I) and 69Ga(II) are almost constant between 4.2 and 100 K, whose values are 1.5 s -1 K -1 at 69Ga(I) and 0.12 s -1 K -1 at 69Ga(II), while the 1/ T 1 T slightly increase above 100K with increasing temperature. The value of T 1 of 69Ga(I) is one order of magnitude less than that of 69Ga(II).

  14. 35Cl NQR study of lattice dynamic and magnetic property of a crystalline coordination polymer {CuCA(phz)(H 2O) 2} n

    NASA Astrophysics Data System (ADS)

    Gotoh, Kazuma; Terao, Takeshi; Asaji, Tetsuo

    2007-01-01

    Copper(II) compounds {CuCA(phz)(H 2O) 2} n (H 2CA = chloranilic acid, phz = phenazine) having a layer structure of -CuCA(H 2O) 2- polymer chains and phenazine were studied by 35Cl nuclear quadrupole resonance (NQR). The single NQR line observed at 35.635 MHz at 261.5 K increased to 35.918 MHz at 4.2 K. The degree of reduction of electric field gradient due to lattice vibrations was similar to that of chloranilic acid crystal. Temperature dependence of spin-lattice relaxation time, T1, of the 35Cl NQR signal below 20 K, between 20 and 210 K, and above 210 K, was explained by (1) a decrease of effective electron-spin density caused by antiferromagnetic interaction, (2) a magnetic interaction between Cl nuclear-spin and electron-spins on paramagnetic Cu(II) ions, and (3) an increasing contribution from reorientation of ligand molecules, respectively. The electron spin-exchange parameter ∣ J∣ between the neighboring Cu(II) electrons was estimated to be 0.33 cm -1 from the T1 value of the range 20-210 K. Comparing this value with that of J = -1.84 cm -1 estimated from the magnetic susceptibility, it is suggested that the magnetic dipolar coupling with the electron spins on Cu(II) ions must be the principal mechanism for the 35Cl NQR spin-lattice relaxation of {CuCA(phz)(H 2O) 2} n but a delocalization of electron spin over the chloranilate ligand has to be taken into account.

  15. Ferromagnetic Quantum Critical Fluctuations and Anomalous Coexistence of Ferromagnetism and Superconductivity in UCoGe Revealed by Co-NMR and NQR Studies

    NASA Astrophysics Data System (ADS)

    Ohta, Tetsuya; Nakai, Yusuke; Ihara, Yoshihiko; Ishida, Kenji; Deguchi, Kazuhiko; Sato, Noriaki K.; Satoh, Isamu

    2008-02-01

    Co nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies were carried out for the recently discovered UCoGe, in which the ferromagnetic and superconducting (SC) transitions are reported to occur at TCurie˜ 3 K and TS˜ 0.8 K [Huy et al.: Phys. Rev. Lett. 99 (2007) 067006], in order to investigate the coexistence of ferromagnetism and superconductivity as well as the normal-state and SC properties from a microscopic point of view. From the nuclear spin-lattice relaxation rate 1/T1 and Knight-shift measurements, we confirm that ferromagnetic fluctuations that possess a quantum critical character are present above TCurie and also the occurrence of a ferromagnetic transition at 2.5 K in our polycrystalline sample. The magnetic fluctuations in the normal state show that UCoGe is an itinerant ferromagnet similar to ZrZn2 and YCo2. The onset SC transition is identified at TS˜ 0.7 K, below which 1/T1 arising from 30% of the volume fraction starts to decrease due to the opening of the SC gap. This component of 1/T1, which follows a T3 dependence in the temperature range 0.3-0.1 K, coexists with the magnetic components of 1/T1 showing a \\sqrt{T} dependence below TS. From the NQR measurements in the SC state, we suggest that the self-induced vortex state is realized in UCoGe.

  16. Temperature variation of ultralow frequency modes and mean square displacements in solid lasamide (diuretic drug) studied by 35Cl-NQR, X-ray and DFT/QTAIM.

    PubMed

    Latosińska, Jolanta Natalia; Latosińska, Magdalena; Kasprzak, Jerzy; Tomczak, Magdalena; Maurin, Jan Krzysztof

    2012-10-25

    The application of combined (35)Cl-NQR/X-ray/DFT/QTAIM methods to study the temperature variation of anisotropic displacement parameters and ultralow frequency modes of anharmonic torsional vibrations in the solid state is illustrated on the example of 2,4-dichloro-5-sulfamolybenzoic acid (lasamide, DSBA) which is a diuretic and an intermediate in the synthesis of furosemide and thus its common impurity. The crystallographic structure of lasamide is solved by X-ray diffraction and refined to a final R-factor of 3.06% at room temperature. Lasamide is found to crystallize in the triclinic space group P-1, with two equivalent molecules in the unit cell a = 7.5984(3) Å, b = 8.3158(3) Å, c = 8.6892(3) Å; α = 81.212(3)°, β = 73.799(3)°, γ = 67.599(3)°. Its molecules form symmetric dimers linked by two short and linear intermolecular hydrogen bonds O-H···O (O-H···O = 2.648 Å and ∠OHO = 171.5°), which are further linked by weaker and longer intermolecular hydrogen bonds N-H···O (N-H···O = 2.965 Å and ∠NHO = 166.4°). Two (35)Cl-NQR resonance frequencies, 36.899 and 37.129 MHz, revealed at room temperature are assigned to chlorine sites at the ortho and para positions, relative to the carboxyl functional group, respectively. The difference in C-Cl(1) and C-Cl(2) bond lengths only slightly affects the value of (35)Cl-NQR frequencies, which results mainly from chemical inequivalence of chlorine atoms but also involvement in different intermolecular interactions pattern. The smooth decrease in both (35)Cl-NQR frequencies with increasing temperature in the range of 77-300 K testifies to the averaging of EFG tensor at each chlorine site due to anharmonic torsional vibrations. Lasamide is thermally stable; no temperature-induced release of chlorine or decomposition of this compound is detected. The temperature dependence of ultralow frequency modes of anharmonic small-angle internal torsional vibrations averaging EFG tensor and mean square angle

  17. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

    SciTech Connect

    Not Available

    1991-12-17

    Our previous studies (1,2) on the zerofield NMR spectra of Cu/Co catalysts revealed that the method of preparation sensitively influences the magnetic character of the Catalyst. Catalytic studies of the earlier investigators also (3) show similar influence on the product selectivity and indicate reproducible performance is critically dependent on the control and rigor of the preparation technique. To compliment the NMR results, we have made a thorough investigation of the Hysteresis character of the Cu/Co catalysts with the metal ratio varying from 0.2 to 4.0.

  18. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

    SciTech Connect

    Not Available

    1991-12-17

    The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.

  19. Sb-NQR study on novel superconductivity in (Pr 1-xLa x)Os 4Sb 12

    NASA Astrophysics Data System (ADS)

    Nagai, Takayuki; Yogi, Mamoru; Imamura, Yoju; Mukuda, Hidekazu; Kitaoka, Yoshio; Kikuchi, Daisuke; Sugawara, Hitoshi; Sato, Hideyuki

    2007-03-01

    We report on superconducting (SC) properties in a series of filled-skutterudite compounds (Pr 1-xLa x)Os 4Sb 12 through the Sb nuclear-quadrupole-resonance (NQR). In the SC state, the nuclear spin-lattice relaxation rate 1/ T1Pr at Pr-cage decreases exponentially with no coherence peak below TC, consistent with the results for the pure PrOs 4Sb 12. In the Pr-rich compounds of x=0.05 and 0.2, the residual density of states (RDOS) at the Fermi level are induced below TC due to the La substitution. It is concluded that the RDOS is not due to the impurity effect that used to be observed in unconventional superconductors with line-node gap. Rather, a part of the Fermi surface that contributes to 5.5% of the total is suggested to become gapless for x=0.05 and 0.2, yielding the RDOS. For the La-rich compounds of x=0.4, 0.8 and 1, as the Pr-substitution for La increases, TC increases and a size of energy gap increases. The Pr-substitution for La makes the pairing interaction for forming the Cooper pairs strong and causes an anisotropy in its energy-gap structure.

  20. Explosives detection by nuclear quadrupole resonance (NQR)

    NASA Astrophysics Data System (ADS)

    Garroway, Allen N.; Buess, Michael L.; Yesinowski, James P.; Miller, Joel B.; Krauss, Ronald A.

    1994-10-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a laboratory prototype NQR explosives detector which interrogates a volume of 300 liters (10 ft3). This paper presents abbreviated results from a demonstration of the laboratory prototype NQR explosives detector conducted at the Federal Aviation Administration Technical Center in May 1994 on RDX-based explosives.

  1. NQR in tert-butyl chloride

    NASA Astrophysics Data System (ADS)

    Brunetti, Aldo H.

    2004-03-01

    Tert-butyl chloride has been broadly studied experimentally through various techniques such as X-ray crystallography, DTA, and NMR. It was also studied experimentally through nuclear quadrupole resonance (NQR), but this study was limited and incomplete. In this paper, we present a more detailed study of TBC through the NQR of 35Cl. Our results show that near 120 K, the onset of the CH 3 groups semirotations around symmetry axis C3 takes place with an activation energy U=16.1 kJ mol -1. This intramolecular movement produces a T1 minimum near 148 K and is the dominant mechanism of the nuclear spin-lattice relaxation in phase III of this compound. In phase II of TBC, we show that there are not only methyl groups semirotations, but also semirotations of the whole molecule around a different axis from the symmetry axis C' 3 (C-Cl bond) with an activation energy of E=10.4 kJ mol -1.

  2. /sup 127/I NQR spectra of carborane-containing compounds of polycoordinated iodine

    SciTech Connect

    Semin, G.K.; Grushin, V.V.; Gushchin, S.I.; Lisichkina, I.N.; Petokhov, S.A.; Tolstaya, T.P.

    1985-05-20

    The NQR spectra of polycoordinated iodine compounds is studied. A table presents the I 127 NQR spectra of electroneutral PhIC1/sub 2/ derivatives with intermolecular coordination in the solid state and ionic compounds including compounds with interionic coordination. A considerable increase in the quadrupole coupling constants and significant decrease in the asymmetry parameter is found in carborane-containing CBIC1/sub 2/ and PhCBIX compounds in comparison with the corresponding phenyl and diphenyl derivatives.

  3. FPGA based pulsed NQR spectrometer

    NASA Astrophysics Data System (ADS)

    Hemnani, Preeti; Rajarajan, A. K.; Joshi, Gopal; Motiwala, Paresh D.; Ravindranath, S. V. G.

    2014-04-01

    An NQR spectrometer for the frequency range of 1 MHz to 5 MHZ has been designed constructed and tested using an FPGA module. Consisting of four modules viz. Transmitter, Probe, Receiver and computer controlled (FPGA & Software) module containing frequency synthesizer, pulse programmer, mixer, detection and display, the instrument is capable of exciting nuclei with a power of 200W and can detect signal of a few microvolts in strength. 14N signal from NaNO2 has been observed with the expected signal strength.

  4. 63Cu NQR in copper (II) compounds

    NASA Astrophysics Data System (ADS)

    Bastow, T. J.; Campbell, I. D.; Whitfield, H. J.

    1980-01-01

    We report observations of 63Cu NQR in CuF 2, KCuF 3, and RbCuF 3 in the paramagnetic state, NQR line widths of 63Cu in CuF 2 and CuBr 2 and of 81Br in CuBr 2, SnBr 2 and ZnBr 2. The NQR resonances of certain Cu (II) paramagnetic compounds are exchange-narrowed to values commensurate with linewidths of the diamagnetic infinite-lattice compounds.

  5. SQUID detected NMR and NQR. Superconducting Quantum Interference Device.

    PubMed

    Augustine, M P; TonThat, D M; Clarke, J

    1998-03-01

    The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K. PMID:9650797

  6. NMR and NQR study of Si-doped (6,0) zigzag single-walled aluminum nitride nanotube as n or P-semiconductors.

    PubMed

    Baei, Mohammad T; Peyghan, Ali Ahmadi; Tavakoli, Khadijeh; Babaheydari, Ali Kazemi; Moghimi, Masoumeh

    2012-09-01

    Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of pristine and Si-doped aluminum nitride nanotubes as n or P-semiconductors at the B3LYP/6-31G* level of theory in order to evaluate the influence of Si-doped in the (6,0) zigzag AlNNTs. We extended the DFT calculation to predict the electronic structure properties of Si-doped aluminum nitride nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Si-doped AlNNT structures in two models (Si(N) and Si(Al)) were optimized, and then the electronic properties, the isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (27)Al and (14)N atoms, NQR parameters for the sites of various of (27)Al and (14)N atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, the electronic properties, NMR and NQR parameters, and quantum molecular descriptors for the Si(N) and Si(Al) models show that the Si(N) model is a more reactive material than the pristine or Si(Al) model. PMID:22588584

  7. Anisotropic pairing in superconducting Sr{sub 2}RuO{sub 4}: Ru NMR and NQR studies

    SciTech Connect

    Ishida, K.; Kitaoka, Y.; Asayama, K.; Ikeda, S.; Nishizaki, S.; Maeno, Y.; Yoshida, K.; Fujita, T.

    1997-07-01

    Ru NMR and nuclear quadrupole resonance studies are reported on single-crystal Sr{sub 2}RuO{sub 4} (T{sub c}=0.7 K) with the same layered perovskite structure as La{sub 2}CuO{sub 4}. The Pauli spin susceptibility deduced from the Ru Knight shift is found to be largely enhanced by a factor of {approximately}5.4 as compared with the value from the band calculation. In the superconducting state, the nuclear spin-lattice relaxation rate 1/T{sub 1} exhibits a sharp decrease with no coherence peak just below T{sub c} and the T{sub 1}T=constant behavior well below T{sub c}, suggesting that the anisotropic pairing state is realized as in heavy-fermion and high-T{sub c} superconductors. {copyright} {ital 1997} {ital The American Physical Society}

  8. A miniaturized NQR spectrometer for a multi-channel NQR-based detection device.

    PubMed

    Beguš, Samo; Jazbinšek, Vojko; Pirnat, Janez; Trontelj, Zvonko

    2014-10-01

    A low frequency (0.5-5 MHz) battery operated sensitive pulsed NQR spectrometer with a transmitter power up to 5 W and a total mass of about 3 kg aimed at detecting (14)N NQR signals, predominantly of illicit materials, was designed and assembled. This spectrometer uses a standard software defined radio (SDR) platform for the data acquisition unit. Signal processing is done with the LabView Virtual instrument on a personal computer. We successfully tested the spectrometer by measuring (14)N NQR signals from aminotetrazole monohydrate (ATMH), potassium nitrate (PN), paracetamol (PCM) and trinitrotoluene (TNT). Such a spectrometer is a feasible component of a portable single or multichannel (14)N NQR based detection device. PMID:25233110

  9. A miniaturized NQR spectrometer for a multi-channel NQR-based detection device

    NASA Astrophysics Data System (ADS)

    Beguš, Samo; Jazbinšek, Vojko; Pirnat, Janez; Trontelj, Zvonko

    2014-10-01

    A low frequency (0.5-5 MHz) battery operated sensitive pulsed NQR spectrometer with a transmitter power up to 5 W and a total mass of about 3 kg aimed at detecting 14N NQR signals, predominantly of illicit materials, was designed and assembled. This spectrometer uses a standard software defined radio (SDR) platform for the data acquisition unit. Signal processing is done with the LabView Virtual instrument on a personal computer. We successfully tested the spectrometer by measuring 14N NQR signals from aminotetrazole monohydrate (ATMH), potassium nitrate (PN), paracetamol (PCM) and trinitrotoluene (TNT). Such a spectrometer is a feasible component of a portable single or multichannel 14N NQR based detection device.

  10. 35Cl NQR frequency and spin lattice relaxation time in 3,4-dichlorophenol as a function of pressure and temperature.

    PubMed

    Ramu, L; Ramesh, K P; Chandramani, R

    2013-01-01

    The pressure dependences of (35)Cl nuclear quadrupole resonance (NQR) frequency, temperature and pressure variation of spin lattice relaxation time (T(1)) were investigated in 3,4-dichlorophenol. T(1) was measured in the temperature range 77-300 K. Furthermore, the NQR frequency and T(1) for these compounds were measured as a function of pressure up to 5 kbar at 300 K. The temperature dependence of the average torsional lifetimes of the molecules and the transition probabilities W(1) and W(2) for the Δm = ±1 and Δm = ±2 transitions were also obtained. A nonlinear variation of NQR frequency with pressure has been observed and the pressure coefficients were observed to be positive. A thermodynamic analysis of the data was carried out to determine the constant volume temperature coefficients of the NQR frequency. An attempt is made to compare the torsional frequencies evaluated from NQR data with those obtained by IR spectra. On selecting the appropriate mode from IR spectra, a good agreement with torsional frequency obtained from NQR data is observed. The previously mentioned approach is a good illustration of the supplementary nature of the data from IR studies, in relation to NQR studies of compounds in solid state. PMID:23161529

  11. Roles of the Sodium-Translocating NADH:Quinone Oxidoreductase (Na+-NQR) on Vibrio cholerae Metabolism, Motility and Osmotic Stress Resistance

    PubMed Central

    Minato, Yusuke; Halang, Petra; Quinn, Matthew J.; Faulkner, Wyatt J.; Aagesen, Alisha M.; Steuber, Julia; Stevens, Jan F.; Häse, Claudia C.

    2014-01-01

    The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I). Thus, Na+-NQR should significantly contribute to multiple aspects of V. cholerae physiology; however, no detailed characterization of this aspect has been reported so far. In this study, we broadly investigated the effects of loss of Na+-NQR on V. cholerae physiology by using Phenotype Microarray (Biolog), transcriptome and metabolomics analyses. We found that the V. cholerae ΔnqrA-F mutant showed multiple defects in metabolism detected by Phenotype Microarray. Transcriptome analysis revealed that the V. cholerae ΔnqrA-F mutant up-regulates 31 genes and down-regulates 55 genes in both early and mid-growth phases. The most up-regulated genes included the cadA and cadB genes, encoding a lysine decarboxylase and a lysine/cadaverine antiporter, respectively. Increased CadAB activity was further suggested by the metabolomics analysis. The down-regulated genes include sialic acid catabolism genes. Metabolomic analysis also suggested increased reductive pathway of TCA cycle and decreased purine metabolism in the V. cholerae ΔnqrA-F mutant. Lack of Na+-NQR did not affect any of the Na+ pumping-related phenotypes of V. cholerae suggesting that other secondary Na+ pump(s) can compensate for Na+ pumping activity of Na+-NQR. Overall, our study provides important insights into the contribution of Na+-NQR to V. cholerae physiology. PMID:24811312

  12. Nanoscale NMR and NQR with Nitrogen Vacancy Centers

    NASA Astrophysics Data System (ADS)

    Urbach, Elana; Lovchinsky, Igor; Sanchez-Yamagishi, Javier; Choi, Soonwon; Bylinskii, Alexei; Dwyer, Bo; Andersen, Trond; Sushkov, Alex; Park, Hongkun; Lukin, Mikhail

    2016-05-01

    Nuclear quadrupole resonance (NQR) is a powerful tool which is used to detect quadrupolar interaction in nuclear spins with I > 1/2. Conventional NQR and NMR technology, however, rely on measuring magnetic fields from a macroscopic number of spins. Extending NMR and NQR techniques to the nanoscale could allow us to learn structural information about interesting materials and biomolecules. We present recent progress on using Nitrogen-Vacancy (NV) centers in diamond to perform room temperature nanoscale NMR and NQR spectroscopy on small numbers of nuclear spins in hexagonal boron nitride.

  13. NQR detection of explosive simulants using RF atomic magnetometers

    NASA Astrophysics Data System (ADS)

    Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) is a highly selective spectroscopic method that can be used to detect and identify a number of chemicals of interest to the defense, national security, and law enforcement community. In the past, there have been several documented attempts to utilize NQR to detect nitrogen bearing explosives using induction sensors to detect the NQR RF signatures. We present here our work on the NQR detection of explosive simulants using optically pumped RF atomic magnetometers. RF atomic magnetometers can provide an order of magnitude (or more) improvement in sensitivity versus induction sensors and can enable mitigation of RF interference, which has classically has been a problem for conventional NQR using induction sensors. We present the theory of operation of optically pumped RF atomic magnetometers along with the result of laboratory work on the detection of explosive simulant material. An outline of ongoing work will also be presented along with a path for a fieldable detection system.

  14. Crystallization and preliminary analysis of the NqrA and NqrC subunits of the Na+-translocating NADH:ubiquinone oxidoreductase from Vibrio cholerae

    PubMed Central

    Vohl, Georg; Nedielkov, Ruslan; Claussen, Björn; Casutt, Marco S.; Vorburger, Thomas; Diederichs, Kay; Möller, Heiko M.; Steuber, Julia; Fritz, Günter

    2014-01-01

    The Na+-translocating NADH:ubiquinone oxidoreductase (Na+-NQR) from Vibrio cholerae is a membrane protein complex consisting of six different subunits NqrA–NqrF. The major domains of the NqrA and NqrC subunits were heterologously expressed in Escherichia coli and crystallized. The structure of NqrA1–377 was solved in space groups C2221 and P21 by SAD phasing and molecular replacement at 1.9 and 2.1 Å resolution, respectively. NqrC devoid of the transmembrane helix was co-expressed with ApbE to insert the flavin mononucleotide group covalently attached to Thr225. The structure was determined by molecular replacement using apo-NqrC of Parabacteroides distasonis as search model at 1.8 Å resolution. PMID:25005105

  15. NQR Characteristics of an RDX Plastic Explosives Simulant.

    PubMed

    Turecek, J; Schwitter, B; Miljak, D; Stancl, M

    2012-12-01

    For reliable detection of explosives, a combination of methods integrated within a single measurement platform may increase detection performance. However, the efficient field testing of such measurement platforms requires the use of inexplosive simulants that are detectable by a wide range of methods. Physical parameters such as simulant density, elemental composition and crystalline structure must closely match those of the target explosive. The highly discriminating bulk detection characteristics of nuclear quadrupole resonance (NQR) especially constrain simulant design. This paper describes the development of an inexplosive RDX simulant suited to a wide range of measurement methods, including NQR. Measurements are presented that confirm an RDX NQR response from the simulant. The potential use of the simulant for field testing a prototype handheld NQR-based RDX detector is analyzed. Only modest changes in prototype operation during field testing would be required to account for the use of simulant rather than real explosive. PMID:23204647

  16. Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

    NASA Astrophysics Data System (ADS)

    Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

    2006-05-01

    Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

  17. Site-directed mutagenesis of conserved cysteine residues in NqrD and NqrE subunits of Na+-translocating NADH:quinone oxidoreductase.

    PubMed

    Fadeeva, M S; Bertsova, Y V; Verkhovsky, M I; Bogachev, A V

    2008-02-01

    Each of two hydrophobic subunits of Na+-translocating NADH:quinone oxidoreductase (NQR), NqrD and NqrE, contain a pair of strictly conserved cysteine residues within their transmembrane alpha-helices. Site-directed mutagenesis showed that substitutions of these residues in NQR of Vibrio harveyi blocked the Na+-dependent and 2-n-heptyl-4-hydroxyquinoline N-oxide-sensitive quinone reductase activity of the enzyme. However, these mutations did not affect the interaction of NQR with NADH and menadione. It was demonstrated that these conserved cysteine residues are necessary for the correct folding and/or the stability of the NQR complex. Mass and EPR spectroscopy showed that NQR from V. harveyi bears only a 2Fe-2S cluster as a metal-containing prosthetic group. PMID:18298367

  18. Structural and Functional Investigation of Flavin Binding Center of the NqrC Subunit of Sodium-Translocating NADH:Quinone Oxidoreductase from Vibrio harveyi

    PubMed Central

    Bertsova, Yulia; Polovinkin, Vitaly; Gushchin, Ivan; Ishchenko, Andrii; Kovalev, Kirill; Mishin, Alexey; Kachalova, Galina; Popov, Alexander; Bogachev, Alexander; Gordeliy, Valentin

    2015-01-01

    Na+-translocating NADH:quinone oxidoreductase (NQR) is a redox-driven sodium pump operating in the respiratory chain of various bacteria, including pathogenic species. The enzyme has a unique set of redox active prosthetic groups, which includes two covalently bound flavin mononucleotide (FMN) residues attached to threonine residues in subunits NqrB and NqrC. The reason of FMN covalent bonding in the subunits has not been established yet. In the current work, binding of free FMN to the apo-form of NqrC from Vibrio harveyi was studied showing very low affinity of NqrC to FMN in the absence of its covalent bonding. To study structural aspects of flavin binding in NqrC, its holo-form was crystallized and its 3D structure was solved at 1.56 Å resolution. It was found that the isoalloxazine moiety of the FMN residue is buried in a hydrophobic cavity and that its pyrimidine ring is squeezed between hydrophobic amino acid residues while its benzene ring is extended from the protein surroundings. This structure of the flavin-binding pocket appears to provide flexibility of the benzene ring, which can help the FMN residue to take the bended conformation and thus to stabilize the one-electron reduced form of the prosthetic group. These properties may also lead to relatively weak noncovalent binding of the flavin. This fact along with periplasmic location of the FMN-binding domains in the vast majority of NqrC-like proteins may explain the necessity of the covalent bonding of this prosthetic group to prevent its loss to the external medium. PMID:25734798

  19. Structural and functional investigation of flavin binding center of the NqrC subunit of sodium-translocating NADH:quinone oxidoreductase from Vibrio harveyi.

    PubMed

    Borshchevskiy, Valentin; Round, Ekaterina; Bertsova, Yulia; Polovinkin, Vitaly; Gushchin, Ivan; Ishchenko, Andrii; Kovalev, Kirill; Mishin, Alexey; Kachalova, Galina; Popov, Alexander; Bogachev, Alexander; Gordeliy, Valentin

    2015-01-01

    Na+-translocating NADH:quinone oxidoreductase (NQR) is a redox-driven sodium pump operating in the respiratory chain of various bacteria, including pathogenic species. The enzyme has a unique set of redox active prosthetic groups, which includes two covalently bound flavin mononucleotide (FMN) residues attached to threonine residues in subunits NqrB and NqrC. The reason of FMN covalent bonding in the subunits has not been established yet. In the current work, binding of free FMN to the apo-form of NqrC from Vibrio harveyi was studied showing very low affinity of NqrC to FMN in the absence of its covalent bonding. To study structural aspects of flavin binding in NqrC, its holo-form was crystallized and its 3D structure was solved at 1.56 Å resolution. It was found that the isoalloxazine moiety of the FMN residue is buried in a hydrophobic cavity and that its pyrimidine ring is squeezed between hydrophobic amino acid residues while its benzene ring is extended from the protein surroundings. This structure of the flavin-binding pocket appears to provide flexibility of the benzene ring, which can help the FMN residue to take the bended conformation and thus to stabilize the one-electron reduced form of the prosthetic group. These properties may also lead to relatively weak noncovalent binding of the flavin. This fact along with periplasmic location of the FMN-binding domains in the vast majority of NqrC-like proteins may explain the necessity of the covalent bonding of this prosthetic group to prevent its loss to the external medium. PMID:25734798

  20. (121,123)Sb and (75)As NMR and NQR investigation of the tetrahedrite (Cu12Sb4S13)--Tennantite (Cu12As4S13) system and other metal arsenides.

    PubMed

    Bastow, T J; Lehmann-Horn, J A; Miljak, D G

    2015-10-01

    This work is motivated by the recent developments in online minerals analysis in the mining and minerals processing industry via nuclear quadrupole resonance (NQR). Here we describe a nuclear magnetic resonance (NMR) and NQR study of the minerals tennantite (Cu12As4S13) and tetrahedrite (Cu12 Sb4S13). In the first part NQR lines associated with (75)As in tennantite and (121,123)Sb isotopes in tetrahedrite are reported. The spectroscopy has been restricted to an ambient temperature studies in accord with typical industrial conditions. The second part of this contribution reports nuclear quadrupole-perturbed NMR findings on further, only partially characterised, metal arsenides. The findings enhance the detection capabilities of NQR based analysers for online measurement applications and may aid to control arsenic and antimony concentrations in metal processing stages. PMID:26453410

  1. Bonding and molecular motions in the 1:1 molecular complexes of 1,4-diazabicyclo[2.2.2]octane with tetrahalomethane as studied by means of NQR

    NASA Astrophysics Data System (ADS)

    Okuda, T.; Suzuki, T.; Negita, H.

    1983-12-01

    NQR spectra were observed in the complexes of 1,4-diazabicyclo[2.2.2]octane (DABCO) with tetrachloromethane and tetrabromomethane at various temperatures. A phase transition was found at 319 K for DABCO·CBr 4. From spin-lattice relaxation times of nitrogen-14 in DABCO·CBr 4, the activation energy of the reorientation of DABCO about the NN axis was calculated to be 18.3 kJ/mol which agrees with the value obtained from the second moment of proton NMR spectra. The bond nature is discussed using the Townes-Dailey treatment.

  2. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, June 15--September 15, 1991

    SciTech Connect

    Not Available

    1991-12-17

    Our previous studies (1,2) on the zerofield NMR spectra of Cu/Co catalysts revealed that the method of preparation sensitively influences the magnetic character of the Catalyst. Catalytic studies of the earlier investigators also (3) show similar influence on the product selectivity and indicate reproducible performance is critically dependent on the control and rigor of the preparation technique. To compliment the NMR results, we have made a thorough investigation of the Hysteresis character of the Cu/Co catalysts with the metal ratio varying from 0.2 to 4.0.

  3. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, June 15--September 15, 1991

    SciTech Connect

    Not Available

    1991-12-17

    The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.

  4. NqrM (DUF539) Protein Is Required for Maturation of Bacterial Na+-Translocating NADH:Quinone Oxidoreductase

    PubMed Central

    Kostyrko, Vitaly A.; Bertsova, Yulia V.; Serebryakova, Marina V.; Baykov, Alexander A.

    2015-01-01

    ABSTRACT Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) catalyzes electron transfer from NADH to ubiquinone in the bacterial respiratory chain, coupled with Na+ translocation across the membrane. Na+-NQR maturation involves covalent attachment of flavin mononucleotide (FMN) residues, catalyzed by flavin transferase encoded by the nqr-associated apbE gene. Analysis of complete bacterial genomes has revealed another putative gene (duf539, here renamed nqrM) that usually follows the apbE gene and is present only in Na+-NQR-containing bacteria. Expression of the Vibrio harveyi nqr operon alone or with the associated apbE gene in Escherichia coli, which lacks its own Na+-NQR, resulted in an enzyme incapable of Na+-dependent NADH or reduced nicotinamide hypoxanthine dinucleotide (dNADH) oxidation. However, fully functional Na+-NQR was restored when these genes were coexpressed with the V. harveyi nqrM gene. Furthermore, nqrM lesions in Klebsiella pneumoniae and V. harveyi prevented production of functional Na+-NQR, which could be recovered by an nqrM-containing plasmid. The Na+-NQR complex isolated from the nqrM-deficient strain of V. harveyi lacks several subunits, indicating that nqrM is necessary for Na+-NQR assembly. The protein product of the nqrM gene, NqrM, contains a single putative transmembrane α-helix and four conserved Cys residues. Mutating one of these residues (Cys33 in V. harveyi NqrM) to Ser completely prevented Na+-NQR maturation, whereas mutating any other Cys residue only decreased the yield of the mature protein. These findings identify NqrM as the second specific maturation factor of Na+-NQR in proteobacteria, which is presumably involved in the delivery of Fe to form the (Cys)4[Fe] center between subunits NqrD and NqrE. IMPORTANCE Na+-translocating NADH:quinone oxidoreductase complex (Na+-NQR) is a unique primary Na+ pump believed to enhance the vitality of many bacteria, including important pathogens such as Vibrio cholerae, Vibrio

  5. The single NqrB and NqrC subunits in the Na(+)-translocating NADH: quinone oxidoreductase (Na(+)-NQR) from Vibrio cholerae each carry one covalently attached FMN.

    PubMed

    Casutt, Marco S; Schlosser, Andreas; Buckel, Wolfgang; Steuber, Julia

    2012-10-01

    The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) is the prototype of a novel class of flavoproteins carrying a riboflavin phosphate bound to serine or threonine by a phosphodiester bond to the ribityl side chain. This membrane-bound, respiratory complex also contains one non-covalently bound FAD, one non-covalently bound riboflavin, ubiquinone-8 and a [2Fe-2S] cluster. Here, we report the quantitative analysis of the full set of flavin cofactors in the Na(+)-NQR and characterize the mode of linkage of the riboflavin phosphate to the membrane-bound NqrB and NqrC subunits. Release of the flavin by β-elimination and analysis of the cofactor demonstrates that the phosphate group is attached at the 5'-position of the ribityl as in authentic FMN and that the Na(+)-NQR contains approximately 1.7mol covalently bound FMN per mol non-covalently bound FAD. Therefore, each of the single NqrB and NqrC subunits in the Na(+)-NQR carries a single FMN. Elimination of the phosphodiester bond yields a dehydro-2-aminobutyrate residue, which is modified with β-mercaptoethanol by Michael addition. Proteolytic digestion followed by mass determination of peptide fragments reveals exclusive modification of threonine residues, which carry FMN in the native enzyme. The described reactions allow quantification and localization of the covalently attached FMNs in the Na(+)-NQR and in related proteins belonging to the Rhodobacter nitrogen fixation (RNF) family of enzymes. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012). PMID:22366169

  6. Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms

    NASA Astrophysics Data System (ADS)

    Malone, Michael W.

    Nuclear Quadrupole Resonance (NQR) is a branch of magnetic resonance physics that allows for the detection of spin I > 1/2 nuclei in crystalline and semi-crystalline materials. Through the application of a resonant radio frequency (rf) pulse, the nuclei's response is to create an oscillating magnetic moment at a frequency unique to the target substance. This creates the NQR signal, which is typically weak and rapidly decaying. The decay is due to the various line broadening mechanisms, the relative strengths of which are functions of the specific material, in addition to thermal relaxation processes. Through the application of a series of rf pulses the broadening mechanisms can be refocused, narrowing the linewidth and extending the signal in time. Three line broadening mechanisms are investigated to explain the NQR signal's linewidth and behavior. The first, electric field gradient (EFG) inhomogeneity, is due to variations in the local electric environment among the target nuclei, for instance from crystal imperfections. While EFG inhomogeneity can vary between samples of the same chemical composition and structure, the other broadening mechanisms of homonuclear and heteronuclear dipolar coupling are specific to this composition and structure. Simple analytical models are developed that explain the NQR signal response to pulse sequences by accounting for the behavior of each broadening mechanism. After a general theoretical introduction, a model of pairs of spin-1 nuclei is investigated, and the refocusing behaviors of EFG and homonuclear dipolar coupling are analyzed. This reveals the conditions where EFG is refocused but homonuclear dipolar coupling is not. In this case the resulting signal shows a rapid decay, the rate of which becomes a measure of interatomic distances. This occurs even in the more complex case of a powder sample with its many randomly oriented crystallites, under particular pulsing conditions. Many target NQR compounds are rich in hydrogen

  7. Enhancing nuclear quadrupole resonance (NQR) signature detection leveraging interference suppression algorithms

    NASA Astrophysics Data System (ADS)

    DeBardelaben, James A.; Miller, Jeremy K.; Myrick, Wilbur L.; Miller, Joel B.; Gilbreath, G. Charmaine; Bajramaj, Blerta

    2012-06-01

    Nuclear quadrupole resonance (NQR) is a radio frequency (RF) magnetic spectroscopic technique that has been shown to detect and identify a wide range of explosive materials containing quadrupolar nuclei. The NQR response signal provides a unique signature of the material of interest. The signal is, however, very weak and can be masked by non-stationary RF interference (RFI) and thermal noise, limiting detection distance. In this paper, we investigate the bounds on the NQR detection range for ammonium nitrate. We leverage a low-cost RFI data acquisition system composed of inexpensive B-field sensing and commercial-off-the-shelf (COTS) software-defined radios (SDR). Using collected data as RFI reference signals, we apply adaptive filtering algorithms to mitigate RFI and enable NQR detection techniques to approach theoretical range bounds in tactical environments.

  8. (14)N NQR, relaxation and molecular dynamics of the explosive TNT.

    PubMed

    Smith, John A S; Rowe, Michael D; Althoefer, Kaspar; Peirson, Neil F; Barras, Jamie

    2015-10-01

    Multiple pulse sequences are widely used for signal enhancement in NQR detection applications. Since the various (14)N NQR relaxation times, signal decay times and frequency of each NQR line have a major influence on detection sequence performance, it is important to characterise these parameters and their temperature variation, as fully as possible. In this paper we discuss such measurements for a number of the ν+ and ν- NQR lines of monoclinic and orthorhombic TNT and relate the temperature variation results to molecular dynamics. The temperature variation of the (14)N spin-lattice relaxation times T1 is interpreted as due to hindered rotation of the NO2 group about the C-NO2 bond with an activation energy of 89 kJ mol(-1) for the ortho and para groups of monoclinic TNT and 70 kJ mol(-1) for the para group of orthorhombic TNT. PMID:26440130

  9. Localization and Function of the Membrane-bound Riboflavin in the Na+-translocating NADH:Quinone Oxidoreductase (Na+-NQR) from Vibrio cholerae*

    PubMed Central

    Casutt, Marco S.; Huber, Tamara; Brunisholz, René; Tao, Minli; Fritz, Günter; Steuber, Julia

    2010-01-01

    The sodium ion-translocating NADH:quinone oxidoreductase (Na+-NQR) from the human pathogen Vibrio cholerae is a respiratory membrane protein complex that couples the oxidation of NADH to the transport of Na+ across the bacterial membrane. The Na+-NQR comprises the six subunits NqrABCDEF, but the stoichiometry and arrangement of these subunits are unknown. Redox-active cofactors are FAD and a 2Fe-2S cluster on NqrF, covalently attached FMNs on NqrB and NqrC, and riboflavin and ubiquinone-8 with unknown localization in the complex. By analyzing the cofactor content and NADH oxidation activity of subcomplexes of the Na+-NQR lacking individual subunits, the riboflavin cofactor was unequivocally assigned to the membrane-bound NqrB subunit. Quantitative analysis of the N-terminal amino acids of the holo-complex revealed that NqrB is present in a single copy in the holo-complex. It is concluded that the hydrophobic NqrB harbors one riboflavin in addition to its covalently attached FMN. The catalytic role of two flavins in subunit NqrB during the reduction of ubiquinone to ubiquinol by the Na+-NQR is discussed. PMID:20558724

  10. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704

    SciTech Connect

    Hirano, Masanori; Yamada, Yuji; Saito, Taku; Nagashima, Ryo; Konishi, Takehisa; Toriyama, Tatsuya; Ohta, Yukinori; Fukazawa, Hideto; Kohori, Yoh; Furukawa, Yuji; Kihou, Kunihiro; Lee, Chul-Ho; Eisaki, Hiroshi

    2012-04-12

    We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on single-crystalline Ba1-xKxFe2As2 for x = 0.27–1. 75As nuclear quadruple resonance frequency (νQ) increases linearly with increasing x. The Knight shift K in the normal state shows Pauli paramagnetic behavior with a weak temperature T dependence. K increases gradually with increasing x. By contrast, the nuclear spin–lattice relaxation rate 1/T1 in the normal state has a strong T dependence, which indicates the existence of large antiferomagnetic (AF) spin fluctuations for all x's. The T dependence of 1/T1 shows a gaplike behavior below approximately 100 K for 0.6 < x < 0.9. This behaviors is well explained by the change in the band structure with the expansion of hole Fermi surfaces and the shrinkage and disappearance of electron Fermi surfaces at the Brillouin zone (BZ) with increasing x. The anisotropy of 1/T1, represented by the ratio of 1/T1ab to 1/T1c, is always larger than 1 for all x's, which indicates that stripe-type AF fluctuations are dominant in this system. The K in the superconducting (SC) state decreases, which corresponds to the appearance of spin-singlet superconductivity. The T dependence of 1/T1 in the SC state indicates a multiple-SC-gap feature. A simple two-gap model analysis shows that the larger superconducting gap gradually decreases with increasing x from 0.27 to 1 and a smaller gap decreases rapidly and nearly vanishes for x > 0.6 where electron pockets in BZ disappear.

  11. Studies of Structure and Phase Transition in [C(NH2)3]HgBr3 and [C(NH2)3]HgI3 by Means of Halogen NQR, 1H NMR, and Single Crystal X-Ray Diffraction

    NASA Astrophysics Data System (ADS)

    Terao, Hiromitsu; Hashimoto, Masao; Hashimoto, Shinichi; Furukawa, Yoshihiro

    2000-02-01

    The crystal structure of [C(NH2)3]HgBr3 was determined at room temperature: monoclinic, space group C2/c, Z = 4, a = 775.0(2), b = 1564.6(2), c = 772.7(2) pm, β = 109.12(2)°. In the crystal, almost planar HgBr3- ions are connected via Hg ··· Br bonds, resulting in single chains of trigonal bipyramidal HgBr5 units which run along the c direction. [C(NH2)3]HgI3 was found to be isomorphous with the bromide at room temperature. The temperature dependence of the halogen NQR frequencies (77 < 77K < ca. 380) and the DTA measurements evidenced no phase transition for the bromide, but a second-order phase transition at (251 ± 1) K (Tc1) and a first-order one at (210 ± 1) K for the iodide. The transitions at Tc2are accompanied with strong supercooling and significant superheating. The room temperature phase (RTP) and the intermediate temperature phase (ITP) of the iodide are characterized by two 127I(m=1/2↔3/2) NQR lines which are assigned to the terminal and the bridging I atoms, respectively. There exist three lines in the lowest temperature phase (LTP), indicating that the resonance line of the bridging atom splits into two. The signal intensities of the 127I(m =1/2↔3/2) NQR lines in the LTP decrease with decreasing temperature resulting in no detection below ca. 100 K. The 127I(m=1/2↔3/2) NQR frequency vs. temperature curves are continuous at Tcl, but they are unusual in the LTP. The T1vs. Tcurves of 1H NMR for the bromide and iodide are explainable by the reorientational motions of the cations about their pseudo three-fold axes. The estimated activation energies of the motions are 35.0 kJ/mol for the bromide, and 24.1, 30.1, and 23.0 kJ/mol for the RTP, FTP, and LTP of the iodide, respectively

  12. Ferromagnetic Spin Fluctuation and Unconventional Superconductivity in Rb2Cr3As3 Revealed by 75As NMR and NQR

    NASA Astrophysics Data System (ADS)

    Yang, J.; Tang, Z. T.; Cao, G. H.; Zheng, Guo-qing

    2015-10-01

    We report 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies on the superconductor Rb2Cr3As3 with a quasi-one-dimensional crystal structure. Below T ˜100 K , the spin-lattice relaxation rate (1 /T1 ) divided by temperature, 1 /T1T , increases upon cooling down to Tc=4.8 K , showing a Curie-Weiss-like temperature dependence. The Knight shift also increases with decreasing temperature. These results suggest ferromagnetic spin fluctuation. In the superconducting state, 1 /T1 decreases rapidly below Tc without a Hebel-Slichter peak, and follows a T5 variation below T ˜3 K , which points to unconventional superconductivity with point nodes in the gap function.

  13. Temperature dependence of 35Cl NQR in 3,4-Dichlorophenol

    NASA Astrophysics Data System (ADS)

    Chandramani, R.; Devaraj, N.; Indumathy, A.; Ramakrishna, J.

    NQR frequencies in 3,4-dichlorophenol are investigated in the temperature range 77 K to room temperature. Two resonances have been observed throughout the temperature range, corresponding to the two chemically inequivalent chlorine sites. Using Bayer's theory and Brown's method torsional frequencies and their temperature dependence in this range are estimated.

  14. The Conformational Changes Induced by Ubiquinone Binding in the Na+-pumping NADH:Ubiquinone Oxidoreductase (Na+-NQR) Are Kinetically Controlled by Conserved Glycines 140 and 141 of the NqrB Subunit*

    PubMed Central

    Strickland, Madeleine; Juárez, Oscar; Neehaul, Yashvin; Cook, Darcie A.; Barquera, Blanca; Hellwig, Petra

    2014-01-01

    Na+-pumping NADH:ubiquinone oxidoreductase (Na+-NQR) is responsible for maintaining a sodium gradient across the inner bacterial membrane. This respiratory enzyme, which couples sodium pumping to the electron transfer between NADH and ubiquinone, is not present in eukaryotes and as such could be a target for antibiotics. In this paper it is shown that the site of ubiquinone reduction is conformationally coupled to the NqrB subunit, which also hosts the final cofactor in the electron transport chain, riboflavin. Previous work showed that mutations in conserved NqrB glycine residues 140 and 141 affect ubiquinone reduction and the proper functioning of the sodium pump. Surprisingly, these mutants did not affect the dissociation constant of ubiquinone or its analog HQNO (2-n-heptyl-4-hydroxyquinoline N-oxide) from Na+-NQR, which indicates that these residues do not participate directly in the ubiquinone binding site but probably control its accessibility. Indeed, redox-induced difference spectroscopy showed that these mutations prevented the conformational change involved in ubiquinone binding but did not modify the signals corresponding to bound ubiquinone. Moreover, data are presented that demonstrate the NqrA subunit is able to bind ubiquinone but with a low non-catalytically relevant affinity. It is also suggested that Na+-NQR contains a single catalytic ubiquinone binding site and a second site that can bind ubiquinone but is not active. PMID:25006248

  15. Measurement of temperature and temperature gradient in millimeter samples by chlorine NQR

    NASA Astrophysics Data System (ADS)

    Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko

    2009-09-01

    A mini-thermometer based on the 35Cl nuclear quadrupole resonance (NQR) frequency temperature dependence in the chlorates KClO3 and NaClO3 was built and successfully tested by measuring temperature and temperature gradient at 77 K and higher in about 100 mm3 active volume of a mini Joule-Thomson refrigerator. In the design of the tank-circuit coil, an array of small coils connected in series enabled us (a) to achieve a suitable ratio of inductance to capacity in the NQR spectrometer input tank circuit, (b) to use a single crystal of KClO3 or NaClO3 (of 1-2 mm3 size) in one coil as a mini-thermometer with a resolution of 0.03 K and (c) to construct a system for measuring temperature gradients when the spatial coordinates of each chlorate single crystal within an individual coil are known.

  16. Coexistence of multiple charge-density waves and superconductivity in SrPt2As2 revealed by 75As-NMR /NQR and 195Pt-NMR

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shinji; Tani, Yoshihiko; Mabuchi, Tomosuke; Kudo, Kazutaka; Nishikubo, Yoshihiro; Mitsuoka, Daisuke; Nohara, Minoru; Zheng, Guo-qing

    2015-02-01

    The relationship between charge-density wave (CDW) orders and superconductivity in arsenide superconductor SrPt2As2 with Tc=5.2 K which crystallizes in the CaBe2Ge2 -type structure was studied by 75As nuclear magnetic resonance (NMR) measurements up to 520 K, and 75As nuclear quadrupole resonance (NQR) and 195Pt-NMR measurements down to 1.5 K. At high temperature, 75As-NMR spectrum and nuclear-spin-relaxation rate (1 /T1) have revealed two distinct CDW orders, one realized in the As-Pt-As layer below TCDWAs (1 )=410 K and the other in the Pt-As-Pt layer below TCDWAs (2 )=255 K . The 1 /T1 measured by 75As-NQR shows a clear Hebel-Slichter peak just below Tc and decreases exponentially well below Tc. Concomitantly, 195Pt Knight shift decreases below Tc. Our results indicate that superconductivity in SrPt2As2 is in the spin-singlet state with an s -wave gap and is robust under the two distinct CDW orders in different layers.

  17. Broadband echo sequence using a pi composite pulse for the pure NQR of a spin I = 32 powder sample

    PubMed

    Odin

    2000-04-01

    This work presents a numerical approach to optimizing sequences with composite pulses for the pure NQR of a spin I = 32 powder sample. The calculations are based on a formalism developed in a previous paper, which allows a fast powder-averaging procedure to be implemented. The framework of the Cayley-Klein matrices to describe space rotations by 2 x 2 unitary and unimodular complex matrices is used to calculate the pulse propagators. The object of such a study is to design a high-performance echo sequence composed of a single preparation pulse and a three-pulse composite transfer pulse. We mean a sequence leading to a large excitation bandwidth with a good signal-to-noise ratio, a flat excitation profile near the irradiation frequency, and a good linearity of the phase as a function of frequency offset. Such a composite echo sequence is intended to give a better excitation profile than the classical Hahn (θ)-tau-(2θ) echo sequence. It is argued that in pure NQR of a powder sample, the sequence must be optimized as a whole since both the excitation and the reception of the signal depend on the relative orientation of the crystallites with respect to the coil axis. To our knowledge, this is the first time such a global approach is presented. An extensive numerical study of the composite echo sequence described above is performed in this article. The key of the discrimination between the sequences lies in using the first five reduced moments of the excitation profile as well as an estimator of the phase linearity. Based on such information, we suggest that the echo sequence that best fulfills our criterion is (1)(0)-tau-(0.35)(0)(2.1)(pi)(0.35)(0), the pulse angles omega(RF)t(p) being in radians. The subscripts are the relative pulse phases. We outlined the way to implement the spin echo mapping method to reconstruct large spectra with this sequence, and it is shown that it reduces the acquisition time by a factor of 1.7 if compared to the classical Hahn echo. Some

  18. Electronic properties of Y-Ba-Cu-O superconductors as seen by Cu and O NMR/NQR

    NASA Technical Reports Server (NTRS)

    Brinkmann, D.

    1995-01-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) allow the investigation of electronic properties at the atomic level. We will report on such studies of typical members of the the Y-Ba-Cu-O family such as YBa2Cu30(6 + x) (1-2-3-(6 + x)), YBa2Cu4O8 (1-2-4) and Y2Ba4Cu7015 (2-4-7) with many examples of recent work performed in our laboratory. In particular, we will deal with Knight shift and relaxation studies of copper and oxygen. We will discuss important issues of current studies such as: (1) Existence of a common electronic spin-susceptibility in the planes (and perhaps in the chains) of 1-2-4; (2) Strong evidence for the existence of a pseudo spin-gap of the antiferromagnetic fluctuations in 1-2-4 and 2-4-7; (3) Evidence for d-wave pairing in 1-2-4; (4) Strong coupling of inequivalent Cu-O planes in 2-4-7 and possible origin for the high Tc value of this compound; and (5) The possibility to describe NMR data in the framework of a charge-excitation picture.

  19. 14N NQR investigation of some thermochromic and photochromic salicylideneanilines and related compounds

    NASA Astrophysics Data System (ADS)

    Hadjoudis, E.; Milia, F.; Seliger, J.; Zagar, V.; Blinc, R.

    1991-09-01

    The temperature dependence of the 14N NQR frequencies have been measured in a series of thermochromic and photochromic salicylideneanilines and related compounds using nuclear quadrupole double resonance. The results show that, in agreement with previous measurements, there is a fast exchange between inequivalent sites in the OH…N bond. The energy difference Δ E of the two proton sites was calculated for all the compounds and shows that it depends on their thermochromic behavior which is connected with the structure of the compounds.

  20. 63Cu NQR spectra of dicoordinated Cu(I) cations with imidazole and pyrazole ligands

    NASA Astrophysics Data System (ADS)

    Khajenhouri, Fereidoun; Motallebi, Shahrock; Lucken, Edwin A. C.

    1995-02-01

    The 63Cu NQR spectra of five dicoordinated complex cations of Cu(I) with substituted imidazoles as ligands and six analogous complexes with substituted pyrazoles as ligands are reported. The structures of four of these complexes have been previously determined and the relationship of their 63Cu resonance frequency to the average CuN bond length is compared to that of the analogous lutidine or collidine complexes. It is concluded that there are probably significant differences between the electronic structures of the pyridine complexes and those of the pyrazole or imidazole series.

  1. Radio-frequency tunable atomic magnetometer for detection of solid-state NQR

    NASA Astrophysics Data System (ADS)

    Lee, S.-K.; Sauer, K. L.; Seltzer, S. J.; Alem, O.; Romalis, M. V.

    2007-06-01

    We constructed a potassium atomic magnetometer which resonantly detects rf magnetic fields with subfemtotesla sensitivity. The resonance frequency is set by the Zeeman resonance of the potassium atoms in a static magnetic field applied to the magnetometer cell. Strong optical pumping of the potassium atoms into a stretched state reduces spin-exchange broadening of the Zeeman resonance, resulting in relatively small linewidth of about 200 Hz (half-width at half-maximum). The magnetometer was used to detect ^14N NQR signal from powdered ammonium nitrate at 423 kHz, with sensitivity an order of magnitude higher than with a conventional room temperature pickup coil with comparable geometry. The demonstrated sensitivity of 0.24 fT/Hz^1/2 can be improved by several means, including use of higher power lasers for pumping and probing. Our technique can potentially be used to develop a mobile, open-access NQR spectrometer for detection of nitrogen-containing solids of interest in security applications.

  2. Critical behavior study of antiferromagnetism in isostructural La2CuO4+δ and La2NiO4+δ

    NASA Astrophysics Data System (ADS)

    White, Benjamin; Neumeier, John; Erb, A.

    2009-03-01

    Neutron diffraction [1] and nuclear quadruple resonance [2] experiments coupled with theory calculations provide substantial evidence to support the widely-accepted belief that the two-dimensional Heisenberg model describes the antiferromagnetic interactions in La2CuO4 (S = .5ex1-.1em/ -.15em.25ex2 ) and La2NiO4 (S = 1). The heat capacity critical exponent α, which could provide further evidence, has never been studied in these two compounds because of the weak nature of the anomalies at TN. [3] We will present heat capacity and high-resolution thermal expansion measurements of La2CuO4 and La2NiO4 single crystals, grown by the floating-zone method, and an analysis of α within the context of predicted values for a variety of universality classes. This material is based upon work supported by the NSF (DMR-0504769) and US DOE Office of Basic Energy Sciences (DE-FG-06ER46269) [1] Y. Endoh et al., PRB 37, 7443 (1988); G. Aeppli and D.J. Buttrey, PRL 61, 203 (1988). [2] P. Carretta, A. Rigamonti, and R. Sala, PRB 55, 3734 (1997). [3] T. Kyomen et al., PRB 60, 14841 (1999); K. Sun et al., PRB 43, 239 (1991).

  3. 14N NQR and the Molecular Charge Topology in Coordinated Ammonia

    NASA Astrophysics Data System (ADS)

    Murgich, Juan; Aray, Yosslen; Ospina, Edgar

    1992-02-01

    14N NQR spectra of [Co(NH3 ) 6 ] • 3Cl, [Co(NH3 ) 5CO3 ] • NO 3 , [Zn(NH3 ) 4 ] • 2Cl, [Zn(NH3 ) 4 ] •(BF4)2, and [Ag(NH3) 4 ] • NO 3 were obtained at 77 K. The results, analyzed by means of the topology of the charge distribution obtained from ab-initio MO calculations of free and of a model of coordinated NH3 , showed that bonding to the metal-ion produces a strong decrease (Co ≫ Zn ≈Ag) in the N nonbonded density ("lone pair") and an increase in the bonded maxima found in the N - H bond direction of the N valence shell.

  4. Detection of {sup 14}N and {sup 35}Cl in cocaine base and hydrochloride using NQR, NMR, and SQUID techniques

    SciTech Connect

    Yesinowski, J.P.; Buess, M.L.; Garroway, A.N.; Ziegeweid, M.; Pines, A. |

    1995-07-01

    Results from {sup 14}N pure NQR of cocaine in the free base form (cocaine base) yield a nuclear quadrupole coupling constant (NQCC) e{sup 2}Qq/h of 5.0229 ({+-}0.0001) MHz and an asymmetry parameter {eta} of 0.0395 ({+-}0.0001) at 295 K, with corresponding values of 5.0460 ({+-}0.0013) MHz and 0.0353 ({+-}0.0008) at 77 K. Both pure NQR (at 295-77 K) and a superconducting quantum interference device (SQUID) detector (at 4.2 K) were used to measure the very low (<1 MHz) {sup 14}N transition frequencies in cocaine hydrochloride; at 295 K the NQCC is 1.1780 ({+-}0.0014) MHz and the asymmetry parameter is 0.2632 ({+-}0.0034). Stepping the carrier frequency enables one to obtain a powder pattern without the severe intensity distortions that otherwise arise from finite pulse power. A powder pattern simulation using an NQCC value of 5.027 MHz and an asymmetry parameter {eta} of 0.2 agrees reasonably well with the experimental stepped-frequency spectrum. The use of pure NQR for providing nondestructive, quantitative, and highly specific detection of crystalline compounds is discussed, as are experimental strategies. 31 refs., 8 figs., 1 tab.

  5. An analytical method for estimating the {sup 14}N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    SciTech Connect

    Iselin, L.H.

    1992-12-31

    The use of {sup 14}N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing {sup 14}N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The {sup 14}N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

  6. I: Low Frequency NMR and NQR Using a dc SQUID. II: Variable-temperature 13C CP/MAS of Organometallics

    SciTech Connect

    Ziegeweid, M.A.

    1995-11-29

    NMR and NQR at low frequencies are difficult prospects due to small nuclear spin polarization. Furthermore, the sensitivity'of the inductive pickup circuitry of standard spectrometers is reduced as the frequency is lowered. I have used a cw-SQUID (Superconducting QUantum Interference Device) spectrometer, which has no such frequency dependence, to study the local atomic environment of {sup 14}N via the quadrupolar interaction. Because {sup 14}N has spin I = 1 and a 0-6 MHz frequency range, it is not possible to obtain well-resolved spectra in high magnetic fields. I have used a technique to observe {sup 14}N NQR resonances via their effect on neighboring protons mediated by the heteronuclear dipolar interaction to study peptides and narcotics. The sensitivity of the SQUID is not enough to measure low-frequency surface (or other low spin density) systems. The application of spin-polarized xenon has been previously used to enhance polarization in conventional NMR experiments. Because xenon only polarizes spins with which it is in contact, it is surface selective. While differences in chemical shifts between surface and bulk spins are not large, it is expected that the differences in quadrupole coupling constant should be very large due to the drastic change of the electric field gradient surrounding spins at the surface. With this in mind, I have taken preliminary steps to measure SQUID detected polarization transfer from Xe to another spin species at 4.2 K and in small magnetic fields (<50 G). In this regime, the spin-lattice relaxation of xenon is dependent on the applied magnetic field. The results of our efforts to characterize the relaxation of xenon are presented. The final section describes the solid-state variable-temperature (VT) one- and two-dimensional {sup 13}C cross polarization (CP)/magic angle spinning (MAS) NMR of Hf({eta}{sup 5}-C{sub 5}H{sub 5}){sub 2}({eta}{sup 1}-C{sub 5}H{sub 5}){sub 2}, Zr({eta}{sup 5}-C{sub 5}H{sub 5}){sub 3}({eta}{sup 1}-C

  7. Persistence of singlet fluctuations in the coupled spin tetrahedra system Cu2Te2O5Br2 revealed by high-field magnetization, 79Br NQR, and 125Te NMR

    NASA Astrophysics Data System (ADS)

    Baek, S.-H.; Choi, K.-Y.; Berger, H.; Büchner, B.; Grafe, H.-J.

    2012-11-01

    We present high-field magnetization and 79Br nuclear quadrupole resonance (NQR) and 125Te nuclear magnetic resonance (NMR) studies in the weakly coupled Cu2+ (S=1/2) tetrahedral system Cu2Te2O5Br2. The field-induced level crossing effects were observed by the magnetization measurements in a long-ranged magnetically ordered state which was confirmed by a strong divergence of the spin-lattice relaxation rate T1-1 at T0=13.5 K. In the paramagnetic state, T1-1 reveals an effective singlet-triplet spin gap much larger than that observed by static bulk measurements. Our results imply that the inter- and the intratetrahedral interactions compete, but at the same time they cooperate strengthening effectively the local intratetrahedral exchange couplings. We discuss that the unusual feature originates from the frustrated intertetrahedral interactions.

  8. Chemical structure and intra-molecular effects on NMR-NQR tensors of harmine and harmaline alkaloids

    NASA Astrophysics Data System (ADS)

    Ahmadinejad, Neda; Tahan, Arezoo; Talebi Tari, Mostafa

    2016-02-01

    Density functional theory (DFT) methods were used to analyze the effects of molecular structure and ring currents on the NMR chemical shielding tensors and NQR frequencies of harmine and harmaline alkaloids in the gas phase. The results demonstrated that NMR tensors and NQR frequencies of 15N nuclei in these compounds depend on chemical environment and resonance interactions. Hence, their values are obviously different in the mentioned structures. The interpretation of natural bond orbital (NBO) data suggests that in harmine structure, the lone pair participation of N9 in π-system electron clouds causes to development of aromaticity nature in pyrrole ring. However, the chemical shielding around N9 atom in harmine structure is higher than in harmaline, while in harmaline structure, lone pair participation of N2 in π-system electron clouds causes to development of aromaticity nature in pyridine ring. Hence, chemical shielding around N2 atom in harmaline structure is higher than in harmine. It can be deduced that by increasing lone pair electrons contribution of nitrogen atoms in ring resonance interactions and aromaticity development, the values of NMR chemical shielding around them increase, while χ and q zz values of these nuclei decrease.

  9. Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat

    NASA Technical Reports Server (NTRS)

    Borsa, F.; Rigamonti, A.

    1991-01-01

    La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for x ranging from 0 up to 0.3, with particular emphasis on the effect of doping on the Cu(2+) magnetic correlations and dynamics, are reviewed. In the low doping limit, x less than or equal to 0.05, the results can be interpreted consistently in terms of a simple phenomenological 'two-fluids' model whereby the effect of thermally-activated mobile O(2p) holes is the one of disrupting locally the Cu(2+) spin correlations. For x greater than or equal to 0.1, the results indicate the onset, as T approaches T(sub c)(+), of a strong coupling between Cu(2+) spins and the Fermi liquid of O(2p) holes leading to the apparent disappearance of localized Cu(2+) moment in connection with the opening of a superconducting gap.

  10. Volovik effect and Fermi-liquid behavior in the s-wave superconductor CaPd2As2: As75 NMR-NQR measurements

    DOE PAGESBeta

    Ding, Q. -P.; Wiecki, P.; Anand, V. K.; Sangeetha, N. S.; Lee, Y.; Johnston, D. C.; Furukawa, Y.

    2016-04-07

    The electronic and magnetic properties of the collapsed-tetragonal CaPd2As2 superconductor (SC) with a transition temperature of 1.27 K have been investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. The temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts indicate the absence of magnetic correlations in the normal state. In the SC state, 1/T1 measured by 75As NQR shows a clear Hebel-Slichter (HS) peak just below Tc and decreases exponentially at lower T, confirming a conventional s-wave SC. Additionally, the Volovik effect, also known as the Doppler shift effect, hasmore » been clearly evidenced by the observation of the suppression of the HS peak with applied magnetic field.« less

  11. Volovik effect and Fermi-liquid behavior in the s -wave superconductor CaPd2As2: 75As NMR-NQR measurements

    NASA Astrophysics Data System (ADS)

    Ding, Q.-P.; Wiecki, P.; Anand, V. K.; Sangeetha, N. S.; Lee, Y.; Johnston, D. C.; Furukawa, Y.

    2016-04-01

    The electronic and magnetic properties of the collapsed-tetragonal CaPd2As2 superconductor (SC) with a transition temperature of 1.27 K have been investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. The temperature (T ) dependence of the nuclear spin lattice relaxation rates (1 /T1) and the Knight shifts indicate the absence of magnetic correlations in the normal state. In the SC state, 1 /T1 measured by 75As NQR shows a clear Hebel-Slichter (HS) peak just below Tc and decreases exponentially at lower T , confirming a conventional s -wave SC. In addition, the Volovik effect, also known as the Doppler shift effect, has been clearly evidenced by the observation of the suppression of the HS peak with applied magnetic field.

  12. Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat

    NASA Technical Reports Server (NTRS)

    Borsa, F.; Rigamonti, A.

    1990-01-01

    La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for O = to or less than 0.3 and in the temperature range 1.6 + 450 K are analyzed in terms of Cu(++) magnetic correlations and dynamics. It is described how the magnetic correlations that would result from Cu-Cu exchange are reduced by mobile charge defects related to x-doping. A comprehensive picture is given which explains satisfactorily the x and T dependence of the correlation time, of the correlation length and of the Neel temperature T(sub n)(x) as well as being consistent with known electrical resistivity and magnetic susceptibility measurements. It is discussed how, in the superconducting samples, the mobile defects also cause the decrease, for T yields T(sub c)(+) of the hyperfine Cu electron-nucleus effective interaction, leading to the coexistence of quasi-localized, reduced magnetic moments from 3d Cu electrons and mobile oxygen p-hole carriers. The temperature dependence of the effective hyperfine field around the superconducting transition yields an activation energy which could be related to the pairing energy. New specific heat measurements are also presented and discussed in terms of the above picture.

  13. (14) N nuclear quadrupole resonance study of piroxicam: confirmation of new polymorphic form V.

    PubMed

    Lavrič, Zoran; Pirnat, Janez; Lužnik, Janko; Puc, Uroš; Trontelj, Zvonko; Srčič, Stane

    2015-06-01

    A new polymorphic crystal form of piroxicam was discovered while preparing crystalline samples of piroxicam for (14) N nuclear quadrupole resonance (NQR) analysis. The new crystal form, designated as V, was prepared by evaporative recrystallization from dichloromethane. Three known polymorphic forms (I, II, and III) were also prepared. Our aim was to apply (14) N NQR to characterize the new polymorphic form of piroxicam and compare the results with those of the other known polymorphic forms. Additional analytical methods used for characterization were X-ray powder diffraction (XRPD), thermal analysis, and vibrational spectroscopy. For the first time, a complete set of nine characteristic (14) N NQR frequencies was found for each prepared polymorph of piroxicam. The consistent set of measured frequencies and calculated characteristic quadrupole parameters found for the new polymorphic form V is a convincing evidence that we are dealing with a new form. The already known piroxicam polymorphic forms were characterized similarly. The XRPD results were in accordance with the conclusions of (14) N NQR analysis. The performed study clearly demonstrates a strong potential of (14) N NQR method to be applied as a highly discriminative spectroscopic analytical tool to characterize polymorphic forms. PMID:25776345

  14. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    SciTech Connect

    Furukawa, Yuji; Roy, Beas; Ran, Sheng; Budko, Sergey L.; Canfield, Paul C.

    2014-03-20

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility χ and the T dependence of 1/T1Tχ, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  15. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    NASA Astrophysics Data System (ADS)

    Furukawa, Y.; Roy, B.; Ran, S.; Bud'ko, S. L.; Canfield, P. C.

    2014-03-01

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility χ and the T dependence of 1/T1Tχ, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  16. Isotope effect on the temperature dependence of the 35Cl NQR frequency in (NH4)2RuCl6

    NASA Astrophysics Data System (ADS)

    Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

    2013-07-01

    The 35Cl nuclear quadrupole resonance frequencies and spin-lattice relaxation times for (NH4)2RuCl6, (ND4)2RuCl6, (NH4)2SnCl6, and (ND4)2SnCl6 were measured in the temperature range 4.2-300 K. In these four compounds, it was confirmed that no phase transition occurs in the observed temperature range. At 4.2 K, discrepancies of the NQR frequency between non-deuterated and deuterated compounds, which are attributed to the difference in the spatial distributions of hydrogen (deuterium) atoms in the ground states of the rotational motion of ammonium ion, reached to 24 kHz and 23 kHz for the ruthenate compounds and the stannate compounds, respectively. The separation between the ground and the first excited states of the rotational motion of the ammonium ion was estimated to be 466 J mol-1 and 840 J mol-1 for (ND4)2RuCl6 and (NH4)2RuCl6, respectively, by least-square fitting calculations of temperature dependence of the NQR frequency. For (ND4)2SnCl6 and (NH4)2SnCl6, these quantities were estimated to be 501 J mol-1 and 1544 J mol-1, respectively. It was clarified that the T1 minimum, which has been observed for the stannate compounds at around 60 K as a feature of the temperature dependence, was dependent on a method of sample preparation. It is concluded that the minimum is not an essential character of the ammonium hexachlorostannate(IV) since the crystals prepared in strong acid condition to prevent a partial substitution of chlorine atoms by hydroxyl groups, did not show such T1 minimum.

  17. Nuclear Quadrupole Resonance Studies of Charge Distributions in Molecular Solids.

    NASA Astrophysics Data System (ADS)

    Greenbaum, Steven Garry

    A detailed description of an NMR-NQR double resonance spectrometer designed and constructed in this laboratory is given, including some instruction on its use. ('14)N NQR data obtained by pulse methods for six classes of nitrogen-containing compounds are presented and analyzed in the framework of the Townes and Dailey theory. A study of the anti-cancer drugs cyclophosphamide, isophosphamide and triphosphamide suggests the existence of a correlation between the substance's chemotherapeutic efficacy and the (pi) - (sigma)(,NP) charge density at the trigonal nitrogen. Satisfactory correlations of the NQR spectra of 22 monosubstituted anilines with both the Hammett (sigma) parameters and the in vitro biological activities of the corresponding sulfanilamides have been found, indicating that the nitrogen lone-pair orbital is more sensitive than the nitrogen-carbon sigma orbital is to substituent effects. NQR spectra of several N-acetyl amino acids and related compounds are reported. The inductive effect of the chloroacetyl group on the nitrogen is discussed. A positive correlation between the (pi) - (sigma)(,NC) electron density at the nitrogen and the Taft inductive parameter (sigma)* is observed, suggesting that the nitrogen (pi) -charge density in the N-acetyl amino acids does not vary appreciably. Both ('14)N and ('35)Cl NQR data have been obtained for a series of compounds containing nitrogen directly bonded to chlorine. The existence of a linear correlation between the ('14)N and ('35)Cl quadrupole coupling constants is interpreted in terms of a simple model dealing with charge excesses and deficiencies at the respective nuclei. A study of two complexes of 4-aminopyridine (4AP) addresses the loss of pyridine nitrogen lone-pair charge upon formation of the strong and asymmetric N-H-N bond characteristic of these complexes. Evidence of hydrogen bonding interactions involving the amino nitrogens is found to be in agreement with a published neutron diffraction study

  18. Synthesis and phtoluminescence study of Microporous Metal Organic Frameworks (MMOFs) for sensing and detection of nitroexplosives and aromatic compounds

    NASA Astrophysics Data System (ADS)

    Pramanik, Sanhita

    Due to the increased terrorist activity worldwide and the use of modern bombs in those attacks, the development of a new method capable of rapidly and cost-efficiently detecting trace vapor of explosives is highly desirable. Chemical explosives composed of a diverse group of compounds, including nitroaromatics, nitramines, nitrate esters as well as some inorganic/organic nitrates and peroxides. Current methodologies include use of well trained dogs and sophisticated instrumentation such as gas chromatography coupled with a mass spectrometer, nuclear quadruple resonance, ionization mass spectrometry (IMS). These methods are highly sensitive and selective, but often expensive, not always easily accessible, and require intense training for operation. As a complementary method, chemical sensors can provide new ways to the rapid detection of ultra trace explosives, and can be easily incorporated into inexpensive and portable microelectronic devices. Fluorescence based sensors utilizing conjugated polymers have attracted enormous attention in the recent years for their excellent performance. In this thesis, a systematic study was performed in a series of luminescent MMOFs and their behavior upon exposure to the vapor of different analytes. For example, [Zn2(oba)2(bpy)]·DMA, one of the MMOFs made of paddle-wheel SBU, selectively responds to nitroaromatics (with electron-withdrawing groups) and other aromatic compounds, like benzene, toluene (with electron-donating groups) via fluorescent quenching and enhancement respectively. The study also shows that nitro-containing non-aromatic analytes (nitroaliphatics) make negligible effect on the fluorescence of [Zn2(oba)2(bpy)]·DMA . The results demonstrate the exceptional ability of this particular MMOF to selectively detect explosives of different types (e.g. aromatic DNT vs. non-aromatic or aliphatic DMNB). Another series of highly luminescent MMOFs made of the same metal center (Zn) and similar ligands (bpdc, bpy, 2,2'dmbpy

  19. Hybridization-driven gap in U3Bi4Ni3: a 209Bi NMR/NQR study

    SciTech Connect

    Baek, Seung H

    2009-01-01

    We report {sup 209}Bi nuclear-magnetic-resonance and nuclear-quadrupole-resonance measurements on a single crystal of the Kondo insulator U{sub 3}Bi{sub 4}Ni{sub 3}. The {sup 209}Bi nuclear-spin-lattice relaxation rate (T{sub 1}{sup -1}) shows activated behavior and is well fit by a spin gap of 220 K. The {sup 209}Bi Knight shift (K) exhibits a strong temperature dependence arising from 5f electrons, in which K is negative at high temperatures and increases as the temperature is lowered. Below 50 K, K shows a broad maximum and decreases slightly upon further cooling. Our data provide insight into the evolution of the hyperfine fields in a fully gapped Kondo insulator based on 5f electron hybridization.

  20. Nuclear quadrupole resonance studies of the SORC sequence and nuclear magnetic resonance studies of polymers

    SciTech Connect

    Jayakody, J.R.P.

    1993-12-31

    The behavior of induction signals during steady-state pulse irradiation in {sup 14}N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work nitrocellulose isotopically highly enriched with {sup 15}N was studied at four different temperatures between 27{degrees} and 120{degrees} Celsius and the correlation times for polymer backbone motions were obtained. Naflon films containing water (D{sub 2}O and H{sub 2} {sup 17}O) and methanol (CH{sub 3}OD, CH{sub 3} {sup 17}OH), have been studied using deuteron and oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the {sup 2}H NMR lineshapes. Activation energies extracted from {sup 2}H spin-lattice relaxation data on the high temperature side of the T{sub 1} minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotrophy of the host polymer.

  1. Nuclear Quadrupole Resonance Studies of the Sorc Sequence and Nuclear Magnetic Resonance Studies of Polymers.

    NASA Astrophysics Data System (ADS)

    Jayakody, Jayakody R. Pemadasa

    1993-01-01

    The behavior of induction signals during steady -state pulse irradiation in ^{14} N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, Cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work Nitrocellulose isotopically highly enriched with ^{15}N was studied at four different temperatures between 27^ circ and 120^circ Celsius and the correlation times for polymer backbone motions were obtained. Nafion films containing, water (D_2 O and H_2^{17}O) and methanol (CH_3OD, CH _3^{17}OH), have been studied using Deuteron and Oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the ^2H NMR lineshapes. Activation energies extracted from ^2H spin-lattice relaxation data on the high temperature side of the T_1 minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotropy of the host polymer. Activation volumes corresponding to a specific dynamical

  2. Undergraduate research studies program at participating institutions of the HBCU Fossil Energy Consortium

    SciTech Connect

    Bota, K.B.

    1991-01-01

    The primary objective of this research program is to expose students in the Historically Black Colleges and Universities (HBCU) Fossil Energy Consortium Institutions to energy and fossil fuels research, to stimulate their interest in the sciences and engineering and to encourage them to pursue graduate studies. This report provides the research accomplishment of the various students who participated in the program. Research results are presented on the following topics: Energy Enhancement and Pollutant Reduction in Coal by Cryogenic Diminution; Competition of NO and SO[sub 2] for OH Generated witin Electrical Aerosol Analyzers; Dispersed Iron Catalysts for Coal Gasification; NQR/NMR Studies of Copper-Cobalt Catalysts for Syngas Concersion; Catalytic gasification of Coal Chars by Potassium Sulfate and Ferrous Sulfate Mixtures; A New Method for Cleaning and Beneficiation of Ultrafine Coal; Characterization Studies of Coal-Derived Liquids; Study of Coal Liquefaction Catalysts and Removal of Certain Toxic Heavy Metal Ions from Coal Conversion Process Wastewaters.

  3. Undergraduate research studies program at participating institutions of the HBCU Fossil Energy Consortium. Final report

    SciTech Connect

    Bota, K.B.

    1991-12-31

    The primary objective of this research program is to expose students in the Historically Black Colleges and Universities (HBCU) Fossil Energy Consortium Institutions to energy and fossil fuels research, to stimulate their interest in the sciences and engineering and to encourage them to pursue graduate studies. This report provides the research accomplishment of the various students who participated in the program. Research results are presented on the following topics: Energy Enhancement and Pollutant Reduction in Coal by Cryogenic Diminution; Competition of NO and SO{sub 2} for OH Generated witin Electrical Aerosol Analyzers; Dispersed Iron Catalysts for Coal Gasification; NQR/NMR Studies of Copper-Cobalt Catalysts for Syngas Concersion; Catalytic gasification of Coal Chars by Potassium Sulfate and Ferrous Sulfate Mixtures; A New Method for Cleaning and Beneficiation of Ultrafine Coal; Characterization Studies of Coal-Derived Liquids; Study of Coal Liquefaction Catalysts and Removal of Certain Toxic Heavy Metal Ions from Coal Conversion Process Wastewaters.

  4. Nuclear magnetic and quadrupole resonance studies of the stripes materials

    NASA Astrophysics Data System (ADS)

    Grafe, H.-J.

    2012-11-01

    Nuclear Magnetic and Quadrupole Resonance (NMR/NQR) is a powerful tool to probe electronic inhomogeneities in correlated electron systems. Its local character allows for probing different environments due to spin density modulations or inhomogeneous doping distributions emerging from the correlations in these systems. In fact, NMR/NQR is not only sensitive to magnetic properties through interaction of the nuclear spin, but also allows to probe the symmetry of the charge distribution and its homogeneity, as well as structural modulations, through sensitivity to the electric field gradient (EFG). We review the results of NMR and NQR in the cuprates from intrinsic spatial variations of the hole concentration in the normal state to stripe order at low temperatures, thereby keeping in mind the influence of doping induced disorder and inhomogeneities. Finally, we briefly discuss NQR evidence for local electronic inhomogeneities in the recently discovered iron pnictides, suggesting that electronic inhomogeneities are a common feature of correlated electron systems.

  5. Origin and Evolution of the Sodium -Pumping NADH: Ubiquinone Oxidoreductase

    PubMed Central

    Reyes-Prieto, Adrian; Barquera, Blanca; Juárez, Oscar

    2014-01-01

    The sodium -pumping NADH: ubiquinone oxidoreductase (Na+-NQR) is the main ion pump and the primary entry site for electrons into the respiratory chain of many different types of pathogenic bacteria. This enzymatic complex creates a transmembrane gradient of sodium that is used by the cell to sustain ionic homeostasis, nutrient transport, ATP synthesis, flagellum rotation and other essential processes. Comparative genomics data demonstrate that the nqr operon, which encodes all Na+-NQR subunits, is found in a large variety of bacterial lineages with different habitats and metabolic strategies. Here we studied the distribution, origin and evolution of this enzymatic complex. The molecular phylogenetic analyses and the organizations of the nqr operon indicate that Na+-NQR evolved within the Chlorobi/Bacteroidetes group, after the duplication and subsequent neofunctionalization of the operon that encodes the homolog RNF complex. Subsequently, the nqr operon dispersed through multiple horizontal transfer events to other bacterial lineages such as Chlamydiae, Planctomyces and α, β, γ and δ -proteobacteria. Considering the biochemical properties of the Na+-NQR complex and its physiological role in different bacteria, we propose a detailed scenario to explain the molecular mechanisms that gave rise to its novel redox- dependent sodium -pumping activity. Our model postulates that the evolution of the Na+-NQR complex involved a functional divergence from its RNF homolog, following the duplication of the rnf operon, the loss of the rnfB gene and the recruitment of the reductase subunit of an aromatic monooxygenase. PMID:24809444

  6. Detecting body cavity bombs with nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Collins, Michael London

    Nuclear Quadrupole Resonance (NQR) is a technology with great potential for detecting hidden explosives. Past NQR research has studied the detection of land mines and bombs concealed within luggage and packages. This thesis focuses on an NQR application that has received less attention and little or no publicly available research: detecting body cavity bombs (BCBs). BCBs include explosives that have been ingested, inserted into orifices, or surgically implanted. BCBs present a threat to aviation and secure facilities. They are extremely difficult to detect with the technology currently employed at security checkpoints. To evaluate whether or not NQR can be used to detect BCBs, a computational model is developed to assess how the dielectric properties of biological tissue affect the radio frequency magnetic field employed in NQR (0.5-5MHz). The relative permittivity of some biological tissue is very high (over 1,000 at 1MHz), making it conceivable that there is a significant effect on the electromagnetic field. To study this effect, the low-frequency approximation known as the Darwin model is employed. First, the electromagnetic field of a coil is calculated in free space. Second, a dielectric object or set of objects is introduced, and the free-space electric field is modified to accommodate the dielectric object ensuring that the relevant boundary conditions are obeyed. Finally, the magnetic field associated with the corrected electric field is calculated. This corrected magnetic field is evaluated with an NQR simulation to estimate the impact of dielectric tissue on NQR measurements. The effect of dielectric tissue is shown to be small, thus obviating a potential barrier to BCB detection. The NQR model presented may assist those designing excitation and detection coils for NQR. Some general coil design considerations and strategies are discussed.

  7. Nuclear Quadrupole Resonance Study of the Nitrogen Mustards and Local Anesthetics.

    NASA Astrophysics Data System (ADS)

    Buess, Michael Lee

    The density matrix description of pulsed nitrogen -14 nuclear quadrupole resonance (NQR) spin-echoes is presented. The parallel between this problem, when formulated in terms of the fictitious spin- 1/2 operators, and that of spin - 1/2 NMR spin-echoes in liquids is discussed along with the complications which arise in multiple-pulse NQR experiments in powders due to the random orientation of the electric field gradient tensors. The equipment and procedures involved in searching for, detecting and identifying NQR resonances using pulsed techniques are described. The ('14)N NQR spectra of several nitrogen mustard compounds in the solid state are reported and analyzed in the framework of the Townes and Dailey theory. For the aniline derivatives, a correlation exists between l -(sigma), l being the nitrogen lone-pair electron density and (sigma) the average N-C sigma bond electron density, and the enhanced Hammett sigma constant (sigma)('-). An improved correlation is obtained between l-(sigma) and (sigma)(,R)('-), which emphasizes the importance of resonance effects in determining l-(sigma). The increase of hydrolysis and alkylation rates with increasing values of l-(sigma) is in agreement with the identification of the cyclic immonium ion as the intermediate in the hydrolysis and alkylation processes of the aromatic nitrogen mustards. A possible correlation is noted between the ('35)Cl NQR spectra for some of the mustards and measures of toxic and antitumor activity. ('14)N NQR spectra for several local anesthetics in the solid state are also reported and analyzed using the Townes and Dailey approach. The changes in the electron distributions at various nitrogen sites, produced by protonating the tertiary amino nitrogen, are discussed and shown to be in general agreement with expectations bases on the increased electrophilic character of the protonated amino group.

  8. Rotational dynamics of water molecules near biological surfaces with implications for nuclear quadrupole relaxation.

    PubMed

    Braun, Daniel; Schmollngruber, Michael; Steinhauser, Othmar

    2016-09-21

    Based on Molecular Dynamics simulations of two different systems, the protein ubiquitin dissolved in water and an AOT reverse micelle, we present a broad analysis of the single particle rotational dynamics of water. A comprehensive connection to NQR, which is a prominent experimental method in this field, is developed, based on a reformulation of its theoretical framework. Interpretation of experimental NQR results requires a model which usually assumes that the NQR experiences retardation only in the first hydration shell. Indeed, the present study shows that this first-shell model is correct. Moreover, previous experimental retardation factors are quantitatively reproduced. All of this is seemingly contradicted by results of other methods, e.g., dielectric spectroscopy, responsible for a long-standing debate in this field. Our detailed analysis shows that NQR omits important information contained in overall water dynamics, most notably, the retardation of the water dipole axis in the electric field exerted by a biological surface. PMID:27546227

  9. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    NASA Astrophysics Data System (ADS)

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3 / 2 , 5 / 2 , 7 / 2, and 9 / 2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  10. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    DOE PAGESBeta

    Cho, Herman

    2016-02-28

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  11. Role of the Na(+)-translocating NADH:quinone oxidoreductase in voltage generation and Na(+) extrusion in Vibrio cholerae.

    PubMed

    Vorburger, Thomas; Nedielkov, Ruslan; Brosig, Alexander; Bok, Eva; Schunke, Emina; Steffen, Wojtek; Mayer, Sonja; Götz, Friedrich; Möller, Heiko M; Steuber, Julia

    2016-04-01

    For Vibrio cholerae, the coordinated import and export of Na(+) is crucial for adaptation to habitats with different osmolarities. We investigated the Na(+)-extruding branch of the sodium cycle in this human pathogen by in vivo (23)Na-NMR spectroscopy. The Na(+) extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR). In a V. cholerae deletion mutant devoid of the Na(+)-NQR encoding genes (nqrA-F), rates of respiratory Na(+) extrusion were decreased by a factor of four, but the cytoplasmic Na(+) concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (ΔΨ, inside negative) and did not grow under hypoosmotic conditions at pH8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na(+)/H(+) antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na(+) concentrations, the Na(+)-NQR is crucial for generation of a transmembrane voltage to drive the import of H(+) by electrogenic Na(+)/H(+) antiporters. Our study provides the basis to understand the role of the Na(+)-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na(+) pump for respiration. PMID:26721205

  12. Impact of structural differences in carcinopreventive agents indole-3-carbinol and 3,3'-diindolylmethane on biological activity. An X-ray, ¹H-¹⁴N NQDR, ¹³C CP/MAS NMR, and periodic hybrid DFT study.

    PubMed

    Latosińska, Jolanta Natalia; Latosińska, Magdalena; Szafrański, Marek; Seliger, Janez; Žagar, Veselko; Burchardt, Dorota V

    2015-09-18

    Three experimental techniques (1)H-(14)N NQDR, (13)C CP/MAS NMR and X-ray and Density Functional Theory (GGA/BLYP with PBC) and Hirshfeld surfaces were applied for the structure-activity oriented studies of two phyto-antioxidants and anticarcinogens: indole-3-carbinol, I3C, and 3,3'-diindolylmethane, DIM, (its bioactive metabolite). One set of (14)N NQR frequencies for DIM (2.310, 2.200 and 0.110 MHz at 295K) and I3C (2.315, 1.985 and 0.330 MHz at 160K) was recorded. The multiplicity of NQR lines recorded at RT revealed high symmetry (chemical and physical equivalence) of both methyl indazole rings of DIM. Carbonyl (13)C CSA tensor components were calculated from the (13)C CP/MAS solid state NMR spectrum of I3C recorded under fast and slow spinning. At room temperature the crystal structure of I3C is orthorhombic: space group Pca21, Z=4, a=5.78922(16), b=15.6434(7) and c=8.4405(2)Å. The I3C molecules are aggregated into ribbons stacked along [001]. The oxygen atomsare disorderedbetween the two sites of different occupancy factors. It implies that the crystal is built of about 70% trans and 30% gauche conformers, and apart from the weak OH⋯O hydrogen bonds (O⋯O=3.106Å) the formation of alternative O'H⋯O bonds (O'⋯O=2.785Å) is possible within the 1D ribbons. The adjacent ribbons are further stabilised by O'H⋯O bonds (O'⋯O=2.951Å). The analysis of spectra and intermolecular interactions pattern by experimental techniques was supported by solid (periodic) DFT calculations. The knowledge of the topology and competition of the interactions in crystalline state shed some light on the preferred conformations of CH2OH in I3C and steric hindrance of methyl indole rings in DIM. A comparison of the local environment in gas phase and solid permitted drawing some conclusions on the nature of the interactions required for effective processes of recognition and binding of a given anticarcinogen to the protein or nucleic acid. PMID:26066413

  13. Induction and inhibition of NAD(P)H: quinone reductase in murine and human skin.

    PubMed

    Merk, H; Jugert, F; Bonnekoh, B; Mahrle, G

    1991-01-01

    The purpose of this study was to characterize the human cutaneous NAD(P)H: quinone reductase (NQR) activity by known inhibitors of different reductases and to compare it with the murine skin and liver NQR activity. This enzyme plays a major role in the defence of cells against oxygen stress because it inhibits the 1-electron reduction of quinones to semiquinones and their subsequent oxidation to quinones termed as quinone redox cycle. It belongs to the aromatic hydrocarbon-responsive (Ah) battery. This gene battery includes Cyp1a1 (cytochrome P-450 IA1), Cyp1a2 (cytochrome P-450 IA2) and Nmo-1 [NAD(P)H: quinone reductase]. In the skin cytochrome P-450 IA1-dependent activity is about 1-5% compared to the corresponding activity in the liver, whereas NQR has the same activity in skin and liver. NQR was determined in the cytoplasm of murine skin, liver, and human keratinocytes using 2,6-dichlorophenolindophenol as the substrate. The Ah-receptor binding compounds, such as coal tar constituents, or 3-methylcholanthrene induce cytochrome P-450-dependent activities such as aryl hydrocarbon hydroxylase or 7-ethoxyresorufin-O-de-ethylase and NQR, whereas butyl hydroxytoluol, which does not bind to the Ah receptor, induces only NQR. For inhibition studies several known inhibitors of dihydrodiol dehydrogenase, aldo-keto and carbonyl reductase activities were used. There was a similar pattern of inhibition of the basal and induced activity in all tissues investigated. Pyrazole, progesterone and phenobarbital did not inhibit, whereas dicoumarol, rutin and indomethacin inhibited NQR activity in murine skin and liver as well as in human keratinocytes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1768430

  14. Number of CuO2 layers dependence of magnetic quantum criticality in homogeneously doped high-T copper oxides: A 63Cu-NMR study on four-layered high-T compounds HgBa2Ca3Cu4O8+y

    NASA Astrophysics Data System (ADS)

    Itohara, Keita; Shimizu, Sunao; Mukuda, Hidekazu; Kitaoka, Yoshio; Shirage, Parasharam M.; Kito, Hijiri; Iyo, Akira

    2010-12-01

    We report 63Cu-NMR/NQR studies on Hg-based four-layered compounds HgBa2Ca3Cu4 O8+y (Hg-1234) with T=123, 110, and 95 K. The 63Cu Knight shift measurements have revealed that the carrier density (N) monotonously decreases with decreasing T. Although static magnetic order was not observed at N=0.15 for the IP with T=95K, it was revealed that antiferromagnetic correlations critically develop, preventing from observing the NMR spectrum below ˜200 K far above T. Thus, we deduce that a magnetic quantum critical point, where an AFM order collapses, may exist at slightly less than N˜0.15 in the Hg-based four-layered compounds, which is lower than that in Hg-based five-layered compounds, N˜0.17. This result suggests that a magnetic interlayer coupling, which stabilizes an AFM order, becomes weaker in the four-layered compounds than in five-layered compounds.

  15. Reexamination of Spin Dynamics in La2CuO4 by Cu-NQR

    NASA Astrophysics Data System (ADS)

    Matsumura, Masahiro; Yasuoka, Hiroshi; Ueda, Yutaka; Yamagata, Hideki; Itoh, Yutaka

    1994-12-01

    The nuclear spin-lattice relaxation rate 1/T1 and the indirect nuclear spin-spin relaxation rate 1/T 2g for 63Cu in La2CuO4 (T N=312 K) were reexamined from 400 K to 1000 K, expanding the temperature range of the first observation by Imai et al. The temperature dependence of 1/T1 is in good agreement with the previous result, while 1/T 2g decreases more rapidly with temperature. The temperature dependences of both 1/T1 and 1/T 2g closely follow the renormalized classical (RC) formula below about 600 K, but deviate from the RC prediction above 600 K. The scaling relation between 1/T1 and 1/T 2g was not confirmed above 600 K, in conflict with the theoretical prediction for the quantum critical (QC) regime. Hence, we argue that the deviation from the RC formula above 600 K does not necessarily correspond to a crossover from the RC to the QC regime.

  16. Synthesis, conformational and NQR analysis of phosphoric triamides containing the P(O)[N]3 skeleton

    NASA Astrophysics Data System (ADS)

    Shariatinia, Zahra; Della Védova, Carlos O.; Erben, Mauricio F.; Tavasolinasab, Vahid; Gholivand, Khodayar

    2012-09-01

    New phosphoric triamides with general formula P(O)X3 where X = N-4-methylpiperazinyl (1), N-4-phenylpiperazinyl (2), N-4-ethoxycarbonyl piperazinyl (3), N-2-tetrahydrofurfuryl (4) were synthesized and characterized by 1H, 13C, 31P NMR, IR, Mass spectroscopy and elemental analysis. The molecular structure for compounds 1-4 were obtained by using quantum chemical calculations (HF and B3LYP methods with the 6-31+G∗∗ basis set). Moreover, optimized structures for previously reported 4-FC6H4C(O)NHP(O)X2 phosphoric triamides, X = pyrrolidin-1-yl (5), piperidin-1-yl (6) and hexamethyleneimin-1-yl (7) were obtained using the solid state structure (CIF files) as a starting point for the gas phase computation in which all independent molecules in structures 6 (seven structures) and 7 (two structures) were included. The computed results were in good agreement with the data obtained from the X-ray crystal structures reported earlier. The nuclear quadrupole coupling constants (NQCCs or χs) were calculated about 5.0 and 10.0 MHz for the 17O atoms of Pdbnd O and Cdbnd O bonds. For nitrogen atoms bonded to the phosphorus the NQCCs were found in the range between 4.0 and 5.5 MHz, whereas for compounds 4-7, the expected values for amidic hydrogen atoms are near 300 kHz.

  17. Pulsed Fourier-transform NQR of 14N with a dc SQUID

    NASA Astrophysics Data System (ADS)

    Hürlimann, M. D.; Pennington, C. H.; Fan, N. Q.; Clarke, John; Pines, A.; Hahn, E. L.

    1992-07-01

    The zero-field free induction decay of solid ammonium perchlorate at 1.5 K has been directly detected with a dc superconducting quantum interference device. The Fourier-transform spectrum consists of three sharp lines at 17.4, 38.8, and 56.2 kHz arising from pure 14N nuclear quadrupole resonance transitions. The absence of splittings and resonance transitions from dipolar-coupled proton spins is attributed to reorientation of the ammonium groups by quantum tunneling in combination with motional averaging in the three proton levels characterized by the irreducible representation T. The measured 14N spin-spin relaxation time is 22+/-2 ms and the spin-lattice relaxation time is 63+/-6 ms.

  18. Using nitrogen-14 nuclear quadrupole resonance and electric field gradient information for the study of radiation effects

    SciTech Connect

    Iselin, L.H.

    1995-12-01

    Nitrogen-14 nuclear quadrupole resonance (NQR) was used in an attempt to detect the effects of ionizing radiation on organic material. Previously reported resonances for urea were detected at 2,913.32 {+-} 0.01 kHz and 2,347.88 {+-} 0.08 kHz with associated T{sub 2}* values 780 {+-} 20 {micro}s and 523 {+-} 24 {micro}s, respectively. The previously unreported {nu}{sub {minus}} line for urea-d{sup 4} was detected at 2,381 {+-} 0.04 Khz and used to determine accurately for the first time the values for the nuclear quadrupole coupling constant {chi} (3,548.74 {+-} 0.03 kHz) and the asymmetry parameter {eta} (0.31571 {+-} 0.00007) for urea-d{sup 4}. The inverse linewidth parameter T{sub 2}* for {nu}{sub +} was measured at 928 {+-} 23 {micro}s and for {nu}{sub {minus}} at 721 {+-} 12 {micro}s. Townes and Dailey analysis was performed and urea-d{sup 4} exhibits a 0.004 increase in lone pair electronic density and a slight decrease in N-H bond electronic density, as compared to urea, probably due to the mass difference. A relationship is proposed, referred to as NQR linewidth analysis, between the dynamic spin relaxation times T{sub 2} and T{sub 2}* and the widths of the distributions of the NQR parameters. Linewidth analysis is presented as a tool for possible use in future NQR work in all area, not just radiation effects. This relationship is tested using sodium nitrite T{sub 2} and T{sub 2}* values for {nu}{sub {minus}} and {nu}{sub {minus}} as a function of temperature.

  19. Solid-state (185/187)Re NMR and GIPAW DFT study of perrhenates and Re2(CO)10: chemical shift anisotropy, NMR crystallography, and a metal-metal bond.

    PubMed

    Widdifield, Cory M; Perras, Frédéric A; Bryce, David L

    2015-04-21

    Advances in solid-state nuclear magnetic resonance (SSNMR) methods, such as dynamic nuclear polarization (DNP), intricate pulse sequences, and increased applied magnetic fields, allow for the study of systems which even very recently would be impractical. However, SSNMR methods using certain quadrupolar probe nuclei (i.e., I > 1/2), such as (185/187)Re remain far from fully developed due to the exceedingly strong interaction between the quadrupole moment of these nuclei and local electric field gradients (EFGs). We present a detailed high-field (B0 = 21.1 T) experimental SSNMR study on several perrhenates (KReO4, AgReO4, Ca(ReO4)2·2H2O), as well as ReO3 and Re2(CO)10. We propose solid ReO3 as a new rhenium SSNMR chemical shift standard due to its reproducible and sharp (185/187)Re NMR resonances. We show that for KReO4, previously poorly understood high-order quadrupole-induced effects (HOQIE) on the satellite transitions can be used to measure the EFG tensor asymmetry (i.e., ηQ) to nearly an order-of-magnitude greater precision than competing SSNMR and nuclear quadrupole resonance (NQR) approaches. Samples of AgReO4 and Ca(ReO4)2·2H2O enable us to comment on the effects of counter-ions and hydration upon Re(vii) chemical shifts. Calcium-43 and (185/187)Re NMR tensor parameters allow us to conclude that two proposed crystal structures for Ca(ReO4)2·2H2O, which would be considered as distinct, are in fact the same structure. Study of Re2(CO)10 provides insights into the effects of Re-Re bonding on the rhenium NMR tensor parameters and rhenium oxidation state on the Re chemical shift value. As overtone NQR experiments allowed us to precisely measure the (185/187)Re EFG tensor of Re2(CO)10, we were able to measure rhenium chemical shift anisotropy (CSA) for the first time in a powdered sample. Experimental observations are supported by gauge-including projector augmented-wave (GIPAW) density functional theory (DFT) calculations, with NMR tensor calculations also

  20. Ferromagnetic critical behavior in U(Co1-xFex)Al (0 ≤x ≤0.02 ) studied by 59Co nuclear quadrupole resonance measurements

    NASA Astrophysics Data System (ADS)

    Karube, K.; Hattori, T.; Ishida, K.; Kimura, N.

    2015-02-01

    In order to investigate physical properties around a ferromagnetic (FM) quantum transition point and a tricritical point (TCP) in the itinerant-electron metamagnetic compound UCoAl, we have performed the 59Co nuclear quadrupole resonance (NQR) measurement for the Fe-substituted U(Co1-xFex)Al(x =0 ,0.5 ,1 ,and2 %) in zero external magnetic field. The Fe concentration dependence of 59Co -NQR spectra at low temperatures indicates that the first-order FM transition occurs at least above x =1 % . The magnetic fluctuations along the c axis detected by the nuclear spin-spin relaxation rate 1 /T2 exhibit an anomaly at Tmax˜20 K and enhance with increasing x . These results are in good agreement with theoretical predictions and indicate the presence of prominent critical fluctuations at the TCP in this system.

  1. Mössbauer Spectroscopic Studies of (Me2NH2)2SnX6 (X = Cl or Br) and Their Related Complexes

    NASA Astrophysics Data System (ADS)

    Katada, Motomi; Afroj, Dilara; Yamauchi, Takashi; Kawata, Satoshi

    2002-07-01

    The temperature dependence in the 119Sn Mössbauer spectral area for {(CH3)2NH2}2SnCl6 was found to be almost linear, although a phase transition of the complex has been suggested by IR, 35Cl NQR and NMRstudies, while an anomaly in the temperature dependence for {(CH3)2NH2}2SnBr6 was found at 235 K, which is close to the phase transition temperature 253 K determined by 89Br NQR. These differences are attributable to molecular motion of the dimethylammonium ion in the complexes. The X-ray powder diffraction pattern of {(CH3)2NH2}2SnCl6 did not change near the phase transition point, but that of {(CH3)2NH2}2SnBr6 changed at 108 - 123 K and 233 - 253 K

  2. Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

    SciTech Connect

    Urban, Jeffry Todd

    2004-12-21

    Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics. The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nuclei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy. The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an

  3. Low-frequency nuclear quadrupole resonance with a dc SQUID

    SciTech Connect

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.

  4. The Kinetic Reaction Mechanism of the Vibrio cholerae Sodium-dependent NADH Dehydrogenase*♦

    PubMed Central

    Tuz, Karina; Mezic, Katherine G.; Xu, Tianhao; Barquera, Blanca; Juárez, Oscar

    2015-01-01

    The sodium-dependent NADH dehydrogenase (Na+-NQR) is the main ion transporter in Vibrio cholerae. Its activity is linked to the operation of the respiratory chain and is essential for the development of the pathogenic phenotype. Previous studies have described different aspects of the enzyme, including the electron transfer pathways, sodium pumping structures, cofactor and subunit composition, among others. However, the mechanism of the enzyme remains to be completely elucidated. In this work, we have studied the kinetic mechanism of Na+-NQR with the use of steady state kinetics and stopped flow analysis. Na+-NQR follows a hexa-uni ping-pong mechanism, in which NADH acts as the first substrate, reacts with the enzyme, and the oxidized NAD leaves the catalytic site. In this conformation, the enzyme is able to capture two sodium ions and transport them to the external side of the membrane. In the last step, ubiquinone is bound and reduced, and ubiquinol is released. Our data also demonstrate that the catalytic cycle involves two redox states, the three- and five-electron reduced forms. A model that gathers all available information is proposed to explain the kinetic mechanism of Na+-NQR. This model provides a background to understand the current structural and functional information. PMID:26004776

  5. The Kinetic Reaction Mechanism of the Vibrio cholerae Sodium-dependent NADH Dehydrogenase.

    PubMed

    Tuz, Karina; Mezic, Katherine G; Xu, Tianhao; Barquera, Blanca; Juárez, Oscar

    2015-08-14

    The sodium-dependent NADH dehydrogenase (Na(+)-NQR) is the main ion transporter in Vibrio cholerae. Its activity is linked to the operation of the respiratory chain and is essential for the development of the pathogenic phenotype. Previous studies have described different aspects of the enzyme, including the electron transfer pathways, sodium pumping structures, cofactor and subunit composition, among others. However, the mechanism of the enzyme remains to be completely elucidated. In this work, we have studied the kinetic mechanism of Na(+)-NQR with the use of steady state kinetics and stopped flow analysis. Na(+)-NQR follows a hexa-uni ping-pong mechanism, in which NADH acts as the first substrate, reacts with the enzyme, and the oxidized NAD leaves the catalytic site. In this conformation, the enzyme is able to capture two sodium ions and transport them to the external side of the membrane. In the last step, ubiquinone is bound and reduced, and ubiquinol is released. Our data also demonstrate that the catalytic cycle involves two redox states, the three- and five-electron reduced forms. A model that gathers all available information is proposed to explain the kinetic mechanism of Na(+)-NQR. This model provides a background to understand the current structural and functional information. PMID:26004776

  6. Evidence for Unconventional Strong-Coupling Superconductivity in PrOs4Sb12: An Sb Nuclear Quadrupole Resonance Study

    NASA Astrophysics Data System (ADS)

    Kotegawa, H.; Yogi, M.; Imamura, Y.; Kawasaki, Y.; Zheng, G.-Q.; Kitaoka, Y.; Ohsaki, S.; Sugawara, H.; Aoki, Y.; Sato, H.

    2003-01-01

    We report Sb-NQR results which evidence a heavy-fermion (HF) behavior and an unconventional superconducting (SC) property in Pr(Os4Sb12 with Tc=1.85 K. The temperature (T) dependence of nuclear-spin-lattice-relaxation rate, 1/T1, and NQR frequency unravel a low-lying crystal-electric-field splitting below T0˜10 K, associated with Pr3+(4f2)-derived ground state. In the SC state, 1/T1 shows neither a coherence peak just below Tc K nor a T3-like power-law behavior observed for anisotropic HF superconductors with the line-node gap. The isotropic energy gap with its size Δ/kB=4.8 K seems to open up across Tc below T*˜2.3 K. It is surprising that Pr(Os4Sb12 looks like an isotropic HF superconductor—it may indeed argue for Cooper pairing via quadrupolar fluctuations.

  7. Applications of Nanoscale NMR Using Ensembles of NV Centers in Diamond

    NASA Astrophysics Data System (ADS)

    Bucher, Dominik; Glenn, David; Walsworth, Ronald

    2016-05-01

    Ensembles of nitrogen vacancy (NV) centers in diamond are now the frontier modality for nuclear magnetic resonance (NMR) signals at length-scales of microns to Angstroms. Promising applications including NMR and nuclear quadrupole resonance (NQR) spectroscopy in sub-nanoliter volumes, studies of diffusion and transport in small samples of biological tissue, and magnetic resonance imaging (MRI) of individual biological cells and molecules. Here, we describe recent progress toward such applications.

  8. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    SciTech Connect

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependent momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.

  9. Effects of charge inhomogeneities on elementary excitations in La2-xSrxCuO₄

    DOE PAGESBeta

    Park, S. R.; Hamann, A.; Pintschovius, L.; Lamago, D.; Khaliullin, G.; Fujita, M.; Yamada, K.; Gu, G. D.; Tranquada, J. M.; Reznik, D.

    2011-12-12

    Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic imaging shows strong variations in real space, and according to nuclear quadrupole resonance (NQR) studies, the charge distribution in the bulk varies on the nanoscale. However, the analysis of the experimental results utilizing spatially averaged probes often ignores this fact. We have performed a detailed investigation of the doping dependence of the energy and linewidth of the zone-boundary Cu-O bond-stretching vibration in La2-xSrxCuO₄ by inelastic neutron scattering. Both our results as well as previously reported angle-dependentmore » momentum widths of the electronic spectral function detected by angle-resolved photoemission can be reproduced by including the same distribution of local environments extracted from the NQR analysis.« less

  10. Electron spin echo envelope modulation of molecular motions of deuterium nuclei

    NASA Astrophysics Data System (ADS)

    Syryamina, V. N.; Maryasov, A. G.; Bowman, M. K.; Dzuba, S. A.

    2015-12-01

    Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy is a powerful technique for the study of hyperfine interactions between an unpaired electron and nearby nuclei in solids, and is employed in quantitative structural studies. Here, we describe the use of ESEEM to study the slow motion of deuterium nuclei using their nuclear quadrupole resonance (NQR) line shapes. Two ESEEM techniques were employed: the conventional three-pulse ESEEM experiment, π/2 - τ - π/2 - T- π/2 - τ - echo, and the four-pulse ESEEM, π/2 - τ - π/2 - T/2 - π - T/2 - π/2 - τ - echo, with the time variable T scanned in both cases. The nitroxide free radical 4-tert-butyliminomethyl-2,2,5,5-tetramethyl(d12)-3-imidazoline-1-oxyl with four deuterated methyl groups was investigated in a glassy ortho-terphenyl matrix over a wide temperature range. It was shown that four-pulse ESEEM allowed measurement of the nearly pure 2H NQR line shape. Between 90 K and 120 K, the ESEEM spectra change drastically. At low temperatures, four-pulse ESEEM spectra show a Pake-like pattern, which evolves into a single line at higher temperatures, which is typical for NQR of rotating methyl CD3 groups. Comparison with literature data on NQR allows estimation of the reorientation rate, k. At ∼100 K, where the spectral changes are most pronounced, k was found to be ∼105 s-1. The spectral linewidths for the three-pulse ESEEM were found to decrease similarly with increasing temperature; so the three-pulse technique is also capable to detect motion of this type. The ESEEM approach, along with site-directed spin labeling, may be useful for detection of motional transitions near the spin labels in biological systems, when information on motion is required in a wide temperature range.

  11. Electron spin echo envelope modulation of molecular motions of deuterium nuclei.

    PubMed

    Syryamina, V N; Maryasov, A G; Bowman, M K; Dzuba, S A

    2015-12-01

    Electron Spin Echo Envelope Modulation (ESEEM) spectroscopy is a powerful technique for the study of hyperfine interactions between an unpaired electron and nearby nuclei in solids, and is employed in quantitative structural studies. Here, we describe the use of ESEEM to study the slow motion of deuterium nuclei using their nuclear quadrupole resonance (NQR) line shapes. Two ESEEM techniques were employed: the conventional three-pulse ESEEM experiment, π/2 - τ - π/2 - T- π/2 - τ - echo, and the four-pulse ESEEM, π/2 - τ - π/2 - T/2 - π - T/2 - π/2 - τ - echo, with the time variable T scanned in both cases. The nitroxide free radical 4-tert-butyliminomethyl-2,2,5,5-tetramethyl(d12)-3-imidazoline-1-oxyl with four deuterated methyl groups was investigated in a glassy ortho-terphenyl matrix over a wide temperature range. It was shown that four-pulse ESEEM allowed measurement of the nearly pure (2)H NQR line shape. Between 90K and 120K, the ESEEM spectra change drastically. At low temperatures, four-pulse ESEEM spectra show a Pake-like pattern, which evolves into a single line at higher temperatures, which is typical for NQR of rotating methyl CD3 groups. Comparison with literature data on NQR allows estimation of the reorientation rate, k. At ∼100K, where the spectral changes are most pronounced, k was found to be ∼10(5)s(-1). The spectral linewidths for the three-pulse ESEEM were found to decrease similarly with increasing temperature; so the three-pulse technique is also capable to detect motion of this type. The ESEEM approach, along with site-directed spin labeling, may be useful for detection of motional transitions near the spin labels in biological systems, when information on motion is required in a wide temperature range. PMID:26583529

  12. Complete topology of the RNF complex from Vibrio cholerae.

    PubMed

    Hreha, Teri N; Mezic, Katherine G; Herce, Henry D; Duffy, Ellen B; Bourges, Anais; Pryshchep, Sergey; Juarez, Oscar; Barquera, Blanca

    2015-04-21

    RNF is a redox-driven ion (Na(+) and in one case possibly H(+)) transporter present in many prokaryotes. It has been proposed that RNF performs a variety of reactions in different organisms, delivering low-potential reducing equivalents for specific cellular processes. RNF shares strong homology with the Na(+)-pumping respiratory enzyme Na(+)-NQR, although there are significant differences in subunit and redox cofactor composition. Here we report a topological analysis of the six subunits of RNF from Vibrio cholerae. Although individual subunits from other organisms have previously been studied, this is the first complete, experimentally derived, analysis of RNF from any one source. This has allowed us to identify and confirm key properties of RNF. The putative NADH binding site in RnfC is located on the cytoplasmic side of the membrane. FeS centers in RnfB and RnfC are also located on the cytoplasmic side. However, covalently attached FMNs in RnfD and RnfG are both located in the periplasm. RNF also contains a number of acidic residues that correspond to functionally important groups in Na(+)-NQR. The acidic residues involved in Na(+) uptake and many of those implicated in Na(+) translocation are topologically conserved. The topology of RNF closely matches the topology represented in the newly published structure of Na(+)-NQR, consistent with the close relation between the two enzymes. The topology of RNF is discussed in the context of the current structural model of Na(+)-NQR, and the proposed functionality of the RNF complex itself. PMID:25831459

  13. A dual role for plant quinone reductases in host-fungus interaction.

    PubMed

    Heyno, Eiri; Alkan, Noam; Fluhr, Robert

    2013-11-01

    Quinone reductases (QR, EC 1.5.6.2) are flavoproteins that protect organisms from oxidative stress. The function of plant QRs has not as yet been addressed in vivo despite biochemical evidence for their involvement in redox reactions. Here, using knock-out (KO) and overexpressing lines, we studied the protective role of two groups of Arabidopsis thaliana cytosolic QRs, Nqr (NAD(P)H:quinone oxidoreductase) and Fqr (flavodoxin-like quinone reductase), in response to infection by necrotrophic fungi. The KO lines nqr(-) and fqr1(-) displayed significantly slower development of lesions of Botrytis cinerea and Sclerotinia sclerotium in comparison to the wild type (WT). Consistent with this observation, the overexpressing line FQR1(+) was hypersensitive to the pathogens. Both the nqr(-) and fqr1(-) displayed increased fluorescence of 2',7'-dichlorofluorescein,‬ a reporter for reactive oxygen species in response to B. cinerea. Infection by B. cinerea was accompanied with increased Nqr and Fqr1 protein levels in the WT as revealed by western blotting. In addition, a marked stimulation of salicylic acid-sensitive transcripts and suppression of jasmonate-sensitive transcripts was observed in moderately wounded QR KO mutant leaves, a condition mimicking the early stage of infection. In contrast to the above observations, germination of conidia was accelerated on leaves of QR KO mutants in comparison with the WT and FQR1(+). The same effect was observed in water-soluble leaf surface extracts. It is proposed that the altered interaction between B. cinerea and the QR mutants is a consequence of subtly altered redox state of the host, which perturbs host gene expression in response to environmental stress such as fungal growth.‬‬‬‬‬‬ PMID:23464356

  14. Molecular insights into the enzymatic diversity of flavin-trafficking protein (Ftp; formerly ApbE) in flavoprotein biogenesis in the bacterial periplasm.

    PubMed

    Deka, Ranjit K; Brautigam, Chad A; Liu, Wei Z; Tomchick, Diana R; Norgard, Michael V

    2016-02-01

    We recently reported a flavin-trafficking protein (Ftp) in the syphilis spirochete Treponema pallidum (Ftp_Tp) as the first bacterial metal-dependent FAD pyrophosphatase that hydrolyzes FAD into AMP and FMN in the periplasm. Orthologs of Ftp_Tp in other bacteria (formerly ApbE) appear to lack this hydrolytic activity; rather, they flavinylate the redox subunit, NqrC, via their metal-dependent FMN transferase activity. However, nothing has been known about the nature or mechanism of metal-dependent Ftp catalysis in either Nqr- or Rnf-redox-containing bacteria. In the current study, we identified a bimetal center in the crystal structure of Escherichia coli Ftp (Ftp_Ec) and show via mutagenesis that a single amino acid substitution converts it from an FAD-binding protein to a Mg(2+) -dependent FAD pyrophosphatase (Ftp_Tp-like). Furthermore, in the presence of protein substrates, both types of Ftps are capable of flavinylating periplasmic redox-carrying proteins (e.g., RnfG_Ec) via the metal-dependent covalent attachment of FMN. A high-resolution structure of the Ftp-mediated flavinylated protein of Shewanella oneidensis NqrC identified an essential lysine in phosphoester-threonyl-FMN bond formation in the posttranslationally modified flavoproteins. Together, these discoveries broaden our understanding of the physiological capabilities of the bacterial periplasm, and they also clarify a possible mechanism by which flavoproteins are generated. PMID:26626129

  15. Nuclear magnetic and quadrupole resonance in metallic powders in the presence of strong quadrupole interaction: Rhenium metal

    SciTech Connect

    Dimitropoulos, C.; Maglione, M.; Borsa, F.

    1988-03-01

    The nuclear-magnetic-resonance and nuclear-quadrupole-resonance (NQR-NMR) spectra of /sup 187/Re and /sup 185/Re in a powder of rhenium metal were measured in the temperature range 5--10 K both in zero field and with an external magnetic field. The zero-field NQR spectrum is severely broadened by a nonuniform distribution of quadrupole interactions. The average quadrupole coupling frequencies measured at 5 K are, for the two isotopes, ..nu../sub Q/ = 39 +- 0.2 MHz (/sup 187/Re) and ..nu../sub Q/ = 40.8 +- 0.3 MHz (/sup 185/Re). The spectra obtained in the presence of an external magnetic field can be interpreted satisfactorily in terms of transitions among the eigenstates of the full Hamiltonian (Zeeman plus quadrupolar). Measurements of relaxation rates yield T/sub 1/T = 0.03 sK, indicating a relaxation mechanism driven by the hyperfine interaction with the conduction electrons. The feasibility of NQR-NMR studies in small metal particles in the presence of strong inhomogeneous quadrupole interactions is assessed

  16. INSTRUMENTS AND METHODS OF INVESTIGATION: New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique

    NASA Astrophysics Data System (ADS)

    Grechishkin, Vadim S.; Sinyavskii, Nikolai Ya

    1997-04-01

    Possibilities of detecting nuclear quadrupole resonance (NQR) signals in explosives and drugs are considered. Direct and indirect NQR techniques for searching substances are described and the potentialities of various experimental methods are compared.

  17. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

    Nuclear Quadrupole Resonance (NQR) is a spectroscopic technique closely related to Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). These techniques, and NQR in particular, induce signals from the material being interrogated that are very specific to the chemical and physical structure of the material, but are relatively insensitive to the physical form of the material. NQR explosives detection exploits this specificity to detect explosive materials, in contrast to other well known techniques that are designed to detect explosive devices. The past two decades have seen a large research and development effort in NQR explosives detection in the United States aimed at transportation security and military applications. Here, I will briefly describe the physical basis for NQR before discussing NQR developments over the past decade, with particular emphasis on landmine detection and the use of NQR in combating IED's. Potential future directions for NQR research and development are discussed.

  18. Analysis of the performance of a phase alternated multiple pulse sequence in spin I = 7/2 zero-field NQR spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, A.

    Zero-field nuclear magnetic resonance spectroscopy of solids containing quadrupole nuclei usually results in broad spectral lines. This line-broadening is due mainly to the inhomogeneity of the electric field gradient (EFG) at the quadrupolar nuclear site. High resolution spectra of such solids can be obtained with the application of suitably designed multiple radiofrequency (RF) pulse sequences. The performance is reported for a periodic and cyclic phase alternated multiple RF pulse sequence (PAPS) in a spin I = 7/2 system in zero external magnetic field. Average Hamiltonian theory based on the Magnus expansion is used to solve the time-dependent Liouville-von Neumann equation of motion of the spin system under the effect of the PAPS sequence. Single transition operators are employed in the spin dynamics calculations. It is shown that the multiple pulse seqeuncearation pulse, suppresses the EFG inhomogeneity to a maximum extent when = 2 . [-- ] 2 , where is the prep1 2 2 N 1 2 1

  19. Covalent Binding of Flavins to RnfG and RnfD in the Rnf Complex from Vibrio cholerae

    PubMed Central

    Backiel, Julianne; Juárez, Oscar; Zagorevski, Dmitri V.; Wang, Zhenyu; Nilges, Mark J.; Barquera, Blanca

    2009-01-01

    Enzymes of the Rnf family are believed to be bacterial redox-driven ion pumps, coupling an oxidoreduction process to the translocation of Na+ across the cell membrane. Here we show for the first time that Rnf is a flavoprotein, with FMN covalently bound to threonine-175 in RnfG and a second flavin bound to threonine-187 in RnfD. Rnf subunits D and G are homologous to subunits B and C of Na+-NQR, respectively. Each of these Na+-NQR subunits includes a conserved S(T)GAT motif, with FMN covalently bound to the final threonine. RnfD and RnfG both contain the same motif, suggesting that they bind flavins in a similar way. In order to investigate this, the genes for RnfD and RnfG from Vibrio cholerae were cloned and expressed individually in that organism. In both cases the produced protein fluoresced under UV illumination on an SDS gel, further indicating the presence of flavin. However, analysis of the mutants RnfG-T175L, RnfD-T278L, and RnfD-T187V showed that RnfG-T175 and RnfD-T187 are the likely flavin ligands. This indicates that, in the case of RnfD, the flavin is bound, not to the SGAT sequence but to the final residues of a TMAT sequence, a novel variant of the flavin binding motif. In the case of RnfG, flavin analysis, followed by MALDI-TOF-TOF mass spectrometry, showed that an FMN is covalently attached to threonine-175, the final threonine of the S(T)GAT sequence. Studies by visible, EPR, and ENDOR spectroscopy showed that, upon partial reduction, the isolated RnfG produces a neutral semiquinone intermediate. The semiquinone species disappeared upon full reduction and was not observed in the denatured protein. A topological analysis combining reporter protein fusion and computer predictions indicated that the flavins in RnfG and RnfD are localized in the periplasmic space. In contrast, in NqrC and NqrB the flavins are located in a cytoplasmic loop. This topological analysis suggests that there may be mechanistic differences between the Rnf and Na+-NQR

  20. Microscopic study of local structure and charge distribution in metallic La{sub 2}CuO{sub 4+{delta}}

    SciTech Connect

    Hammel, P.C.; Reyes, A.P.; Ahrens, E.T.; Fisk, Z.; Canfield, P.C.; Thompson, J.D.; Schirber, J.E.

    1993-10-29

    The authors employ NMR and NQR spectroscopy as probes of local structure and charge environments in metallic La{sub 2}CuO{sub 4+{delta}} ({Tc} = 38 K). They discuss the effect of annealing the sample at various temperatures T{sub a} ({Tc} < T{sub a} < 300K) on the superconducting {Tc}. The dependence of {Tc} on annealing indicates that annealing allows the development of structural order which is important for {Tc}. The {sup 139}La quadrupole frequency, {nu}{sub Q} is smaller than in undoped materials. This is unexpected and may indicate a smaller charge on the apex oxygen in the doped material and thus a different distribution of charge between the La-O layer to the planes. The further, rapid decrease in {nu}{sub Q} just above {Tc} indicates that temperature dependent charge redistribution is occurring. The presence of doped holes induces a distribution of displacements of the apex oxygen off of the vertical La-Cu bond axis. These vary from zero to the value observed in lightly doped (antiferromagnetic) La{sub 2}CuO{sub 4+{delta}}. These measurements demonstrate a striking degree of inhomogeneity in the crystal structure of the La-O layer. Copper NQR spectroscopy shows that there are two distinct copper sites in the CuO{sub 2} planes and thus that either the structure or the charge distribution in the planes is inhomogeneous as well. These inhomogeneities are the intrinsic response of the crystal to doped holes; they are not the result of distortions of the lattice due to the presence of interstitial oxygen atoms.

  1. 1H and 13C NMR study of substituted 3-OH pyridines

    NASA Astrophysics Data System (ADS)

    De Kowalewski, D. G.; De Los Santos, C.

    1990-04-01

    nJHH, nJCH and δ 13C values have been measured for a series of X substituted 3-hydroxypyridines (X = 2-NH 2, 2-NO 2, 5-Cl, 6-CH 3, 2-Cl, 2-Br, 2-I). The results show that the additivity of δ 13C provides a valuable criterion to differentiate the phenolic from the zwitterion structure. This conclusion is based on the fact that in the first case, for 2-NH 2-, 2-NO 2-, 5-Cl- and 6-CH 3-3-hydroxypyridines, there is agreement between the experimental and the additivity δ 13C values, while in the three halogen derivatives (2-Cl-, 2-Br- and 2-I-3-hydroxypyridines) the δ exp—addC3 values of -4.95, -7.25 and 9.05 are probably due to the negative charge present on the three position of the zwitterion. Since the additivity of 1JCH values holds in all substances examined (unlike the case of the 2-pyridone derivatives) it is not possible to use that criterion to differentiate between the phenolic and dipolar structures. The above conclusions are in agreement with IR, p K, NQR, RX, kinetics experiments and quantum chemical calculations of other authors.

  2. 79Br Nuclear Quadrupole Relaxation in the High Temperature Modification of Niobium Pentabromide

    NASA Astrophysics Data System (ADS)

    Okubo, Noriaki; Sekiya, Harutaka; Ishikawa, Chiaki; Abe, Yoshihito

    1992-06-01

    The spin-lattice relaxation time of 79Br NQR has been measured between 4.2 K and room temperature. The result is compared with that of 35Cl NQR in NbCl5. The origin of the relaxation is attributed to the quadrupolar interaction and the temperature dependence is explained by the Raman process. The Debye temperature is determined to be 94 K and the relaxation time is related with the NQR frequency through the covalency.

  3. Polarization enhanced Nuclear Quadrupole Resonance with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Malone, Michael W.; Barrall, Geoffrey A.; Espy, Michelle A.; Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) has been demonstrated for the detection of 14-N in explosive compounds. Application of a material specific radio-frequency (RF) pulse excites a response typically detected with a wire- wound antenna. NQR is non-contact and material specific, however fields produced by NQR are typically very weak, making demonstration of practical utility challenging. For certain materials, the NQR signal can be increased by transferring polarization from hydrogen nuclei to nitrogen nuclei using external magnetic fields. This polarization enhancement (PE) can enhance the NQR signal by an order of magnitude or more. Atomic magnetometers (AM) have been shown to improve detection sensitivity beyond a conventional antenna by a similar amount. AM sensors are immune to piezo-electric effects that hamper conventional NQR, and can be combined to form a gradiometer for effective RF noise cancellation. In principle, combining polarization enhancement with atomic magnetometer detection should yield improvement in signal-to-noise ratio that is the product of the two methods, 100-fold or more over conventional NQR. However both methods are even more exotic than traditional NQR, and have never been combined due to challenges in operating a large magnetic field and ultra-sensitive magnetic field sensor in proximity. Here we present NQR with and without PE with an atomic magnetometer, demonstrating signal enhancement greater than 20-fold for ammonium nitrate. We also demonstrate PE for PETN using a traditional coil for detection with an enhancement factor of 10. Experimental methods and future applications are discussed.

  4. Narcotics and explosives detection by 14N pure nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Garroway, Allen N.; Buess, Michael L.; Yesinowski, James P.; Miller, Joel B.

    1994-03-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

  5. Image restoration using fast Fourier and wavelet transforms

    NASA Astrophysics Data System (ADS)

    Harrod, William J.; Nagy, James G.; Plemmons, Robert J.

    1994-02-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

  6. Effect of a weak static magnetic field on nitrogen-14 quadrupole resonance in the case of an axially symmetric electric field gradient tensor.

    PubMed

    Guendouz, Laouès; Aissani, Sarra; Marêché, Jean-François; Retournard, Alain; Marande, Pierre-Louis; Canet, Daniel

    2013-01-01

    The application of a weak static B0 magnetic field (less than 1 mT) may produce a well-defined splitting of the (14)N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. It is theoretically shown and experimentally confirmed that the actual splitting (when it exists) as well as the line-shape and the signal intensity depends on three factors: (i) the amplitude of B0, (ii) the amplitude and pulse duration of the radio-frequency field, B1, used for detecting the NQR signal, and (iii) the relative orientation of B0 and B1. For instance, when B0 is parallel to B1 and regardless of the B0 value, the signal intensity is three times larger than when B0 is perpendicular to B1. This point is of some importance in practice since NQR measurements are almost always performed in the earth field. Moreover, in the course of this study, it has been recognized that important pieces of information regarding line-shape are contained in data points at the beginning of the free induction decay (fid) which, in practice, are eliminated for avoiding spurious signals due to probe ringing. It has been found that these data points can generally be retrieved by linear prediction (LP) procedures. As a further LP benefit, the signal intensity loss (by about a factor of three) is regained. PMID:24183810

  7. Aspartic Acid 397 in Subunit B of the Na+-pumping NADH:Quinone Oxidoreductase from Vibrio cholerae Forms Part of a Sodium-binding Site, Is Involved in Cation Selectivity, and Affects Cation-binding Site Cooperativity

    PubMed Central

    Shea, Michael E.; Juárez, Oscar; Cho, Jonathan; Barquera, Blanca

    2013-01-01

    The Na+-pumping NADH:quinone complex is found in Vibrio cholerae and other marine and pathogenic bacteria. NADH:ubiquinone oxidoreductase oxidizes NADH and reduces ubiquinone, using the free energy released by this reaction to pump sodium ions across the cell membrane. In a previous report, a conserved aspartic acid residue in the NqrB subunit at position 397, located in the cytosolic face of this protein, was proposed to be involved in the capture of sodium. Here, we studied the role of this residue through the characterization of mutant enzymes in which this aspartic acid was substituted by other residues that change charge and size, such as arginine, serine, lysine, glutamic acid, and cysteine. Our results indicate that NqrB-Asp-397 forms part of one of the at least two sodium-binding sites and that both size and charge at this position are critical for the function of the enzyme. Moreover, we demonstrate that this residue is involved in cation selectivity, has a critical role in the communication between sodium-binding sites, by promoting cooperativity, and controls the electron transfer step involved in sodium uptake (2Fe-2S → FMNC). PMID:24030824

  8. Biofeasibility Study.

    ERIC Educational Resources Information Center

    Chaparian, Michael

    1995-01-01

    Discusses the use of bioremediation as a method for disposing of contaminants by exploiting natural biodegradation processes. The process of conducting a biofeasibility study and a case study are reviewed. (LZ)

  9. Intelligence Studies

    ERIC Educational Resources Information Center

    Monaghan, Peter

    2009-01-01

    To make an academic study of matters inherently secret and potentially explosive seems a tall task. But a growing number of scholars are drawn to understanding spycraft. The interdisciplinary field of intelligence studies is mushrooming, as scholars trained in history, international studies, and political science examine such subjects as the…

  10. Social Studies.

    ERIC Educational Resources Information Center

    Bieber, Edward

    The product of a Special Studies Institute, this teacher developed resource guide for the emotionally handicapped (K-6) presents social study concepts and activities relative to education in the urban out-of-doors. Focus is on the study of man (past, present, and future) interacting with his environment. Listed below are activity examples: (1)…

  11. College Studying.

    ERIC Educational Resources Information Center

    Nist, Sherrie L.; Simpson, Michele

    2002-01-01

    Notes that many students enter postsecondary institutions unprepared to meet the studying demands placed on them. Examines models and taxonomies that have guided researchers as they have investigated studying. Reviews research factors related to studying at the college level: course characteristics, learner characteristics, and learning…

  12. Toxicity Studies.

    PubMed

    2016-01-01

    Toxicity studies in the animal models are done to determine the dose level recommended for the treatment of disease as drug. This guideline enables the characterization of adverse effects following repeated daily inhalation exposure to a test. This chapter includes oral and dermal toxicity studies which are discussed as per OECD guidelines. Both acute and subacute toxicity studies are given special emphasis. PMID:26939270

  13. Nondestructive testing of adhesive bonds by nuclear quadrupole resonance method

    NASA Technical Reports Server (NTRS)

    Hewitt, R. R.

    1971-01-01

    Inert, strain sensitive tracer, cuprous oxide, added to polymeric adhesive ensures sufficiently large signal to noise ratio in NQR system output. Method is successful, provided that RF-transparent structural materials are used between modified adhesive and probe of NQR spectrometer.

  14. Aerosal studies

    NASA Technical Reports Server (NTRS)

    Harris, F. S., Jr.

    1976-01-01

    Various methods of measuring aerosols were studied in terms of the best methods to use, the instruments or techniques actually employed, and those techniques applied in field measurements on air quality as influenced by rocket launch effluents, and in an urban environment. Further studies were initiated on the remote sensing of aerosols by satellites and the influence of aerosols on visibility. The characterization of aerosols by measurement of scattered light was studied on Mie theory calculations.

  15. Stream Studies.

    ERIC Educational Resources Information Center

    Hamilton City Board of Education (Ontario).

    This manual provides teachers with some knowledge of ecological study methods and techniques used in collecting data when plants and animals are studied in the field. Most activities deal with the interrelatedness of plant and animal life to the structure and characteristics of a stream and pond. Also included in this unit plan designed for the…

  16. Women's Studies.

    ERIC Educational Resources Information Center

    Davis, James E., Ed.; Davis, Hazel K., Ed.

    1981-01-01

    The 16 articles in this journal issue deal with women's studies within the English curriculum. Topics discussed in the articles include (1) the feminist challenge to the male-centered curriculum in higher education; (2) the women's movement and women's studies; (3) connotations of the word "girl"; (4) women in English education; (5) the new…

  17. Study Skills.

    ERIC Educational Resources Information Center

    Thomas, Anne

    1993-01-01

    Three developments lend support to the idea that schools must help teach study skills: (1) advances in cognitive psychology that suggest children are active learners; (2) society's concern for at-risk students; and (3) growing demands for improved student performance. There is evidence that systematic study skills instruction does improve academic…

  18. Studying Zooarchaeology

    ERIC Educational Resources Information Center

    Moore, Molly; Wolf, Deborah; Butler, Virginia L.

    2012-01-01

    Children often associate the study of bones with dinosaurs or crime scenes. This unit introduces students to "zooarchaeology," the study of animal remains from archaeological sites. Students in grades 3-5 engage in hands-on activities examining bones, shells, and other "hard parts" of animals. They use their observations as a starting point for…

  19. SISTER STUDY

    EPA Science Inventory

    The Sister Study will investigate the role of genetic, environmental, and lifestyle factors on the risk of breast cancer and other diseases in sisters of women with breast cancer. This research study will enroll 50,000 women who live in the United States and who are the cancer-fr...

  20. Social Studies.

    ERIC Educational Resources Information Center

    White, Cam, Ed.

    This document contains the following papers on social studies instruction and technology: (1) "Waking the Sleeping Giant: Social Studies Teacher Educators Collaborate To Integrate Technology into Methods' Courses" (Cheryl Mason, Marsha Alibrandi, Michael Berson, Kara Dawson, Rich Diem, Tony Dralle, David Hicks, Tim Keiper, and John Lee); (2)…

  1. Culture Studies: Hawaiian Studies Project.

    ERIC Educational Resources Information Center

    Hazama, Dorothy, Ed.

    Reports and materials from the Hawaiian Studies Project are presented. The document, designed for elementary school teachers contains two major sections. The first section describes the planning phase of the project, the Summer Institute for Hawaiian Culture Studies (1976) and the follow-up workshops and consultant help (1976-77). The appendix to…

  2. NEUROTOXICITY STUDIES

    EPA Science Inventory

    The neurotoxicity of DBPs in general has not been well characterized. The literature provides reports of neurotoxicity of DCA following exposures to relatively high doses. Studies completed at EPA, however, have shown that relatively low doses of DCA (as low as 16 mg/kg/day; simi...

  3. Readability Study.

    ERIC Educational Resources Information Center

    White, Robert; Jordan, William

    A readability study for the Albuquerque Technical-Vocational Institute (T-VI) was undertaken to provide information regarding the reading ability required to complete training and to function in entry-level jobs. Readability formulas were applied to materials used in training and on the job. In addition, students were tested for level of reading,…

  4. Case Studies

    ERIC Educational Resources Information Center

    Ritter, Lois A., Ed.; Sue, Valerie M., Ed.

    2007-01-01

    This article presents two case studies using online surveys for evaluation. The authors begin with an example of a needs assessment survey designed to measure the amount of help new students at a university require in their first year. They then discuss the follow-up survey conducted by the same university to measure the effectiveness of the…

  5. MEDIEVAL STUDIES.

    ERIC Educational Resources Information Center

    MARTONFFY, ANDREA PONTECORVO; AND OTHERS

    A CURRICULUM GUIDE ON MEDIEVAL STUDIES IS PRESENTED, INCLUDING TEACHER MATERIALS AND STUDENT PROBLEM SETS. THE TEACHER MATERIALS DESCRIBE AND EXPLAIN THE ECONOMIC, SOCIAL, AND POLITICAL ASPECTS OF MANORIAL LIFE--THE PREDOMINANT FORM OF AGRICULTURAL LIFE IN NORTHERN FRANCE, ENGLAND, AND GERMANY DURING THE PERIOD FROM APPROXIMATELY 800 TO 1300 A.D.…

  6. IMMUNOTOXICITY STUDIES

    EPA Science Inventory

    Few D/DBPs have been evaluated for effects on the immune system, but certain studies suggest that immunosuppression may follow exposure to D/DBPs. Suppressed immune function is associated with increased susceptibility to infectious disease and certain types of cancer in humans a...

  7. Discipline Study.

    ERIC Educational Resources Information Center

    Queer, Glenn E.

    This report discusses a study designed to elicit opinions from Pittsburgh School District principals, parents, and teachers concerning corporal punishment and other disciplinary action. Questionnaires were aimed at (1) determining reactions to current regulations governing the use of corporal punishment, (2) eliciting instances of experience or…

  8. Research Study

    ERIC Educational Resources Information Center

    Glick, Ashley

    2010-01-01

    Background: Action Research about my 2nd grade classroom in the Buffalo School District. I examined three areas of interest and tried to find some conclusions related to behavior management. Purpose: The purpose of this study is how will implementing procedures, rules, and consequences help improve student behavior. Research Design: Descriptive;…

  9. Study Design for Sequencing Studies.

    PubMed

    Honaas, Loren A; Altman, Naomi S; Krzywinski, Martin

    2016-01-01

    Once a biochemical method has been devised to sample RNA or DNA of interest, sequencing can be used to identify the sampled molecules with high fidelity and low bias. High-throughput sequencing has therefore become the primary data acquisition method for many genomics studies and is being used more and more to address molecular biology questions. By applying principles of statistical experimental design, sequencing experiments can be made more sensitive to the effects under study as well as more biologically sound, hence more replicable. PMID:27008009

  10. Retrospective studies.

    PubMed

    Silveira, Patrícia Pelufo; Manfro, Gisele Gus

    2015-01-01

    Large retrospective, epidemiological studies accumulated in the late 1980s, providing increasing evidence to the deeply rooted thought that perinatal events could persistently affect the individual's functioning and health/disease patterns throughout the lifetime. Evidences of such associations can be found in the literature since the beginning of the twentieth century, but studies from Barker, Hales, and colleagues serve as an important hallmark. They proposed the "thrifty phenotype" hypothesis, stating that poor nutrition in fetal and early infant life is detrimental to the development and function of the individuals' organism, predisposing them to the later development of adult chronic diseases. At first used to explain the increased risk for type 2 diabetes in low birth weight individuals, the hypothesis was soon adapted to other systems, becoming one of the core assumptions of the Developmental Origins of Adult Health and Disease (DOHaD) model. The central nervous system is also vulnerable to the effects of environmental variation during fetal or neonatal life. Many researchers have explored the effects of perinatal programming on the human neurodevelopment, and some aspects of the brain structure and/or functioning (such as cognitive function, physiological reactivity to stress, and the risk for behavioral disorders or psychopathology) were shown to be modifiable by the exposure to certain adverse events early in life such as neonatal infections, exposure to gestational psychosocial stress, nutrition during gestation, exposure to drugs, or tobacco smoking during pregnancy. Until recently, most studies focused on birth weight as a strong surrogate of the intrauterine environment, investigating the effects of low birth weight (as a marker of suboptimal fetal environment) on a variety of neurodevelopmental outcomes. Despite the fact that literature reviews on this topic are as old as 1940, the more recent retrospective studies are summarized in this chapter

  11. Cholera studies*

    PubMed Central

    Pollitzer, R.

    1956-01-01

    The first portion of this study describes in detail the different aspects of stool examinations, including the collection, preservation, and pooling of specimens, macroscopic and bacterioscopic examination, enrichment methods, and cultivation on a variety of solid media. The author also deals with the examination of vomits and of water. The performance and value of different identification tests (agglutination, haemolysis, and bacteriophage) and confirmatory tests are then considered. An annex is included on bacteriological procedures in the laboratory diagnosis of cholera. PMID:13356145

  12. Cholera studies*

    PubMed Central

    Pollitzer, R.

    1957-01-01

    Discussing the symptomatology of cholera, the author deals first with the incubation period, the clinical types, choleraic diarrhoea, and cholerine; he then considers in detail the various stages of cholera gravis and the relapses and complications that may be met. This is followed by sections on diagnosis and differential diagnosis, and on prognosis and the various factors influencing it. The author's highly detailed review of the treatment of cholera which concludes this study is divided into three parts, dealing with attempts at specific therapy, with infusion treatment, and with adjuvant treatment. PMID:13426761

  13. Anticorrosion studies

    NASA Technical Reports Server (NTRS)

    Boerio, J.

    1986-01-01

    The aging behavior of chemically bonded interfaces between metals and pottants, such as ethylene vinyl acetate (EVA) was studied using the Dow Corning primer systems. It was observed that the primers seem to function as anticorrosive agents on metal surfaces. It was demonstrated that EVA, and the A-11861 EVA/glass primer stops corrosion of the aluminum used on the back surfaces of crystalline silicon solar cells. However, this same treatment does not work for the aluminum on the back surfaces of amorphous silicon solar cells.

  14. Ethnobotanical Study.

    PubMed

    2016-01-01

    Ethnobotany is the study of interrelationships between human cultures and plants, animals, and other organisms in their environment. It also creates an awareness of the link between biodiversity and cultural diversity. From the beginning of civilization, people have been using plants for various purposes like food, shelter, medicines, etc. Ethnobotanists play a key role in exploring these kinds of information from indigenous people which creates a gateway for formulating a novel drug. The content in this chapter deals with these aspects in an approachable manner. PMID:26939258

  15. Anticorrosion studies

    NASA Astrophysics Data System (ADS)

    Boerio, J.

    The aging behavior of chemically bonded interfaces between metals and pottants, such as ethylene vinyl acetate (EVA) was studied using the Dow Corning primer systems. It was observed that the primers seem to function as anticorrosive agents on metal surfaces. It was demonstrated that EVA, and the A-11861 EVA/glass primer stops corrosion of the aluminum used on the back surfaces of crystalline silicon solar cells. However, this same treatment does not work for the aluminum on the back surfaces of amorphous silicon solar cells.

  16. Cholera studies*

    PubMed Central

    Swaroop, S.; Pollitzer, R.

    1955-01-01

    In this study, figures relating to cholera deaths occurring in individual countries, from 1900 to 1952, are recorded as well as the incidence of the disease from 1923 up to the present time. The mode of spread of cholera from its endemic home in India to outside countries is described in relation to favourable seasons, main routes followed by the infection, and the role played by large religious gatherings. The incidence of the disease in the various seaports infected within recent years is discussed. PMID:14364186

  17. Plague studies*

    PubMed Central

    Pollitzer, R.

    1953-01-01

    In examining the control and prevention of plague, the author pays particular attention to the control of commensal rodents and their fleas. The various rat poisons in current use, their efficacy and practical application, and the dangers involved in their manipulation are described in great detail. The author also discusses other anti-rodent measures such as fumigation, rat-proofing, sanitation, protection of food, etc. The second part of the study deals with: vector control—the outstanding value of DDT application in rodent-flea control is emphasized—, the direct control of bubonic and pneumonic plague, and the control of the spread of plague at a distance. PMID:20603968

  18. Complementary Study

    SciTech Connect

    Yamada, H.

    2009-02-19

    In this lecture, it is emphasized that sufficient resolution of scientific issues for a fusion energy reactor can be given by complementary studies. Key scientific issues for a fusion energy reactor and ITER addressed by a complementary study in the Large Helical Device (LHD) are discussed. It should be noted that ITER is definitely a necessary condition but not a sufficient condition. Helical systems including stellarators and heliotrons are defined as alternative concepts. These approaches also aim at a fusion energy reactor based on their own concept and simultaneously benefit progress in tokamaks, more specifically ITER itself. The exact science to manage a 3-D geometry has been being developed in helical systems. A physical model with much accuracy and breadth will demonstrate its applicability to ITER. Topics to validate ''complementary'' approaches such as 3-D equilibrium, interchange MHD mode, control of radial electric field and structure formation, dynamics of a magnetic island, density limit and edge plasmas are discussed. Complementary is not Supplementary. ITER is complementary to development of a helical fusion energy reactor as well. Complementary approaches transcend existing disciplinary horizons and enable big challenges.

  19. Nutritional studies

    NASA Technical Reports Server (NTRS)

    Rambaut, P. C.; Smith, M. C., Jr.; Wheeler, H. O.

    1975-01-01

    Detailed metabolic studies were conducted of the Apollo 16 and Apollo 17 flight crews, and the results are presented in tabular form. Intake and absorption data are also included. Apollo nutrient intakes were found to be characteristically hypocaloric. Estimates of body composition changes from metabolic balance data, from preflight and postflight weights and volumes, and from total body water and potassium provide no evidence for diminished caloric requirements during a flight. As observed during the Gemini Program and during periods of bed rest, measurements of bone density and metabolic balance confirm a tendency toward loss of skeletal tissue in weightlessness. No evidence exists that any inflight metabolic anomaly, including hypokalemia, was induced by marginal or deficient nutrient intakes. In general, the Apollo crewmen were well nourished and exhibited normal gastroenterological functions, although appetite was somewhat diminished and the organoleptic response to food was somewhat modified during flight.

  20. Plague studies*

    PubMed Central

    Pollitzer, R.

    1953-01-01

    Epidemiological aspects of (a) bubonic plague and (b) primary pneumonic plague are discussed separately in this study. The cause, spread, and persistence of bubonic outbreaks are dealt with. In the case of primary pneumonic plague, the author systematically reviews the factors influencing the spread of the disease: climatic and social conditions, infectivity of the patients, immunity, and control measures. In discussing the cause of pneumonic plague outbreaks, the author deals with the possible influence of a special virulence of pneumonic strains, the role of the rodent and flea species involved, and the possibility of a pneumotropismus acquired by Pasteurella pestis. The periodicity (cyclical and secular) of bubonic plague epidemics is discussed with a view to the possible forecasting of future epidemics. The author indicates the influence of race, age, sex, and occupation on the incidence of both forms of the disease. PMID:13082391

  1. Cholera studies*

    PubMed Central

    Pollitzer, R.

    1957-01-01

    In discussing prevention, the author deals first with the provision of permanently safe water, supplied from waterworks or wells, and with other improvements in environmental sanitation. Control of food and drinks, public health propaganda and education, and vaccination are also considered under this heading. The greater part of this study is devoted to suppressive measures, affecting the individual, the environment, and persons in the mass. Discussion of the isolation, detection and management of cholera patients, the management of contacts, and the management and treatment of carriers is followed by sections on, inter alia, disinfection, temporary improvements in water supplies, fly control, and personal prophylaxis. In dealing with mass prophylaxis, the author pays particular attention to vaccination. In the concluding sections he goes into the control of pilgrimages and local and international quarantine measures. PMID:13479774

  2. Cholera studies*

    PubMed Central

    Pollitzer, R.

    1957-01-01

    The first section of this study deals with areas where cholera is endemic and with the conditions normally favouring endemicity. Turning next to epidemics, the author discusses their origin and types, climatic influences on them, their periodicity and the possibility of forecasting them, the role played in them by different serological races of V. cholerae, and the causes of their decline. In a section on the factors governing the local spread of cholera, he considers contact and water-borne infection; the role of contaminated food and drink, of fomites, of flies, and of carriers; and the incidence according to sex, age, race, and occupation. The last part deals with factors governing the spread of cholera over longer distances, and includes discussion of the effect of movements of individuals and groups and of assemblies of the population on pilgrimages or at religious festivals. PMID:13472431

  3. Plague studies*

    PubMed Central

    Pollitzer, R.

    1953-01-01

    The author examines in detail the symptomatology, diagnosis, and treatment of plague, and outlines the problem of the length of the incubation period. The clinical features commonly met with in all severely-affected plague patients, regardless of the primary localization of the infection, are described. The author then deals with the symptomatology and manifestations of bubonic plague as compared to those of primary pneumonic plague. The importance of a clinical diagnosis, from the point of view of prevention, is stressed, and the differential diagnosis of various forms of the disease is described. The study contains a detailed discussion of the respective merits of antibiotic treatment, serotherapy, and sulfonamide treatment. The author points out that the outstanding success of streptomycin and some other antibiotics will probably relegate the sulfonamides to the second rank in the treatment of bubonic plague. PMID:13082390

  4. Systems Studies

    SciTech Connect

    Graham, R.L.

    1998-03-17

    The Systems Studies Activity had two objectives: (1) to investigate nontechnical barriers to the deployment of biomass production and supply systems and (2) to enhance and extend existing systems models of bioenergy supply and use. For the first objective, the Activity focused on existing bioenergy markets. Four projects were undertaken: a comparative analysis of bioenergy in Sweden and Austria; a one-day workshop on nontechnical barriers jointly supported by the Production Systems Activity; the development and testing of a framework for analyzing barriers and drivers to bioenergy markets; and surveys of wood pellet users in Sweden, Austria and the US. For the second objective, two projects were undertaken. First, the Activity worked with the Integrated BioEnergy Systems (TBS) Activity of TEA Bioenergy Task XIII to enhance the BioEnergy Assessment Model (BEAM). This model is documented in the final report of the IBS Activity. The Systems Studies Activity contributed to enhancing the feedstock portion of the model by developing a coherent set of willow, poplar, and switchgrass production modules relevant to both the US and the UK. The Activity also developed a pretreatment module for switchgrass. Second, the Activity sponsored a three-day workshop on modeling bioenergy systems with the objectives of providing an overview of the types of models used to evaluate bioenergy and promoting communication among bioenergy modelers. There were nine guest speakers addressing different types of models used to evaluate different aspects of bioenergy, ranging from technoeconomic models based on the ASPEN software to linear programming models to develop feedstock supply curves for the US. The papers from this workshop have been submitted to Biomass and Bioenergy and are under editorial review.

  5. Noncentrosymmetric superconductivity in a clean crystal of type II superconductor Bi-Pd

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Srinivasan; Pratap, Bhanu; Thamizhavel, A.

    2016-02-01

    In this work, we present the bulk superconductivity of a high-quality single crystal of monoclinic BiPd (α-BiPd, space group P21) below 3.8 K by studying its electrical resistivity, magnetic susceptibility, and heat capacity. This is the cleanest noncentrosymmetric superconductor (NCS) that display anisotropy due to spin-orbit scattering and also exhibits unusual superconducting properties due to s and p wave mixing as evidenced by the observation of Andreev bound state and multiple energy gaps via point contact measurements. In addition, Fermi surface studies suggest multiband superconductivity in this compound. Penetration depth studies and NQR investigations support mixing of s and p wave Copper paring in this crystal. Moroever, Muon spin rotation measurements indicate strong field dependence of the Ginzburg- Landau coefficient of this superconductor. Unusual pairing and multiband superconductivity are extremely sensitive to disorder and they can be observed only in cleanest (RRR > 170) single crystals.

  6. Optical and Nuclear Spin Spectroscopy in PRASEODYMIUM(3+):LANTHANUM Fluoride by Optical Pumping

    NASA Astrophysics Data System (ADS)

    Wald, Lawrence Leroy

    A Stark Modulated Optical Pumping (SMOP) technique was used as a sensitive probe of optical hole-burning to study the effects of nuclear spin interactions in Pr ^{3+}:LaF_3. The results of two experiments are reported. In the first experiment, the SMOP technique is applied for optical detection of the NQR spectrum of the Pr^{3+} optical ground state. Frequency and linewidth variations of the Pr ^{3+} ground state hyperfine levels for different positions within the main ^3 H_4(Gamma1) -^1D_2(Gamma 1) inhomogeneous optical line and satellite transitions of Pr^{3+}:LaF _3 are observed. A linear increase in the broadening of the Pr^{3+} hyperfine transitions, without a shift of central frequency, is measured as the laser is tuned toward the wings of the inhomogeneous optical transition. The linear variation is attributed to electric quadrupole broadening caused by changes in local density of point defects across the Stark broadened optical transition. The optically detected NQR spectra of the satellite transitions associated with Pr ion pairs are shifted in frequency, and for most satellites are narrower in width than the NQR spectra found in the wings of the main inhomogeneous optical line. In the second experiment, direct evidence for the presence of a spin diffusion barrier or "frozen core" in Pr^{3+}:LaF _3 is observed by examining the cross relaxation between the Pr and F nuclei in a magnetic field chosen so that a pair of the optical ground state Pr^ {3+} hyperfine energy levels matches the F splitting or a multiple of the F splitting. This level crossing condition allows resonant flip-flop interactions with the nearest neighbor frozen core fluorine spins to re-populate Pr^{3+} hyperfine levels emptied by laser hole-burning, and is detected as enhanced absorption of the laser beam. The coupling of core fluorine spins to bulk fluorine spins during Pr-F cross-relaxation is measured by NMR of the bulk fluorine spin magnetization. The rate of cross relaxation between

  7. Apparent spin-spin relaxation times, T 2★, of some nitrogen compounds using a super-regenerative nuclear quadrupole spectrometer

    NASA Astrophysics Data System (ADS)

    Trepanier, R. J.; Whitehead, M. A.

    The T 2★ of hexainethylenetetramine, C 6H 12 N 4, and sodium nitrite, NaNO 2, at 297°K and 77°K, and of 4-methoxy analine, C 5H 9 NO, at 297°K are reported. Two different nitrogen super-regenerative N.Q.R. spectrometers were used. Two different techniques for obtaining T 2★ were used: one measured the shift in signal detection threshold quench frequency with changing sample mass; the other measured the change in signal intensity for a small change of quench frequency near threshold. The importance of quench frequency studies and spectrometer construction for signal detection are discussed.

  8. 14N quadrupole resonance and 1H T1 dispersion in the explosive RDX.

    PubMed

    Smith, John A S; Blanz, Martin; Rayner, Timothy J; Rowe, Michael D; Bedford, Simon; Althoefer, Kaspar

    2011-12-01

    The explosive hexahydro-1,3,5-trinitro-s-triazine (CH2-N-NO2)3, commonly known as RDX, has been studied by 14N NQR and 1H NMR. NQR frequencies and relaxation times for the three ν+ and ν- lines of the ring 14N nuclei have been measured over the temperature range 230-330 K. The 1H NMR T1 dispersion has been measured for magnetic fields corresponding to the 1H NMR frequency range of 0-5.4 M Hz. The results have been interpreted as due to hindered rotation of the NO2 group about the N-NO2 bond with an activation energy close to 92 kJ mol(-1). Three dips in the 1H NMR dispersion near 120, 390 and 510 kHz are assigned to the ν0, ν- and ν+ transitions of the 14NO2 group. The temperature dependence of the inverse line-width parameters T2∗ of the three ν+ and ν- ring nitrogen transitions between 230 and 320 K can be explained by a distribution in the torsional oscillational amplitudes of the NO2 group about the N-NO2 bond at crystal defects whose values are consistent with the latter being mainly edge dislocations or impurities in the samples studied. Above 310 K, the 14N line widths are dominated by the rapid decrease in the spin-spin relaxation time T2 due to hindered rotation of the NO2 group. A consequence of this is that above this temperature, the 1H T1 values at the quadrupole dips are dominated by the spin mixing time between the 1H Zeeman levels and the combined 1H and 14N spin-spin levels. PMID:21978662

  9. Fostering Effective Studying and Study Planning with Study Questions

    ERIC Educational Resources Information Center

    Wilhelm, Pascal; Pieters, Jules M.

    2007-01-01

    In a course on biological psychology and neuropsychology, study questions were provided that also appeared as test questions in the course exam. This method was introduced to support students in active processing and reproduction of the study texts, and study planning. Data were gathered to test the hypothesis that study question use would be…

  10. Case Study: Testing with Case Studies

    ERIC Educational Resources Information Center

    Herreid, Clyde Freeman

    2015-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue discusses using case studies to test for knowledge or lessons learned.

  11. AGRICULTURAL HEALTH STUDY/PESTICIDE EXPOSURE STUDY

    EPA Science Inventory

    The Agricultural Health Study (AHS) is a prospective epidemiologic study of a large cohort of pesticide applicators and their spouses in Iowa and North Carolina. The Pesticide Exposure Study is a sub-study to evaluate exposure factors and to provide data to assess exposure cla...

  12. Authentication of Medicines Using Nuclear Quadrupole Resonance Spectroscopy.

    PubMed

    Chen, Cheng; Zhang, Fengchao; Barras, Jamie; Althoefer, Kaspar; Bhunia, Swarup; Mandal, Soumyajit

    2016-01-01

    The production and sale of counterfeit and substandard pharmaceutical products, such as essential medicines, is an important global public health problem. We describe a chemometric passport-based approach to improve the security of the pharmaceutical supply chain. Our method is based on applying nuclear quadrupole resonance (NQR) spectroscopy to authenticate the contents of medicine packets. NQR is a non-invasive, non-destructive, and quantitative radio frequency (RF) spectroscopic technique. It is sensitive to subtle features of the solid-state chemical environment and thus generates unique chemical fingerprints that are intrinsically difficult to replicate. We describe several advanced NQR techniques, including two-dimensional measurements, polarization enhancement, and spin density imaging, that further improve the security of our authentication approach. We also present experimental results that confirm the specificity and sensitivity of NQR and its ability to detect counterfeit medicines. PMID:26841409

  13. Nuclear quadrupole resonance lineshape analysis for different motional models: Stochastic Liouville approach

    NASA Astrophysics Data System (ADS)

    Kruk, D.; Earle, K. A.; Mielczarek, A.; Kubica, A.; Milewska, A.; Moscicki, J.

    2011-12-01

    A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary motional conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow motion theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000), 10.1006/jmre.2000.2125] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion models. The two latter models account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow motion spectra to the mechanism of the motional processes modulating the nuclear quadrupole interaction is discussed.

  14. Spin dynamics in CuO and Cu[sub 1[minus][ital x

    SciTech Connect

    Carretta, P.; Corti, M.; Rigamonti, A. )

    1993-08-01

    [sup 63]Cu nuclear quadrupole resonance (NQR), nuclear antiferromagnetic resonance (AFNMR), and spin-lattice relaxation, as well as [sup 7]Li NMR and relaxation measurements in CuO and in Cu[sub 1[minus][ital x

  15. The application of frequency swept pulses for the acquisition of nuclear quadrupole resonance spectra

    NASA Astrophysics Data System (ADS)

    Rossini, Aaron J.; Hamaed, Hiyam; Schurko, Robert W.

    2010-09-01

    The acquisition of nuclear quadrupole resonance (NQR) spectra with wideband uniform rate and smooth truncation (WURST) pulses is investigated. 75As and 35Cl NQR spectra acquired with the WURST echo sequence are compared to those acquired with standard Hahn-echo sequences and echo sequences which employ composite refocusing pulses. The utility of WURST pulses for locating NQR resonances of unknown frequency is investigated by monitoring the integrated intensity and signal to noise of 35Cl and 75As NQR spectra acquired with transmitter offsets of several hundreds kilohertz from the resonance frequencies. The WURST echo sequence is demonstrated to possess superior excitation bandwidths in comparison to the pulse sequences which employ conventional monochromatic rectangular pulses. The superior excitation bandwidths of the WURST pulses allows for differences in the characteristic impedance of the receiving and excitation circuits of the spectrometer to be detected. Impedance mismatches have previously been reported by Marion and Desvaux [D.J.Y. Marion, H. Desvaux, J. Magn. Reson. (2008) 193(1) 153-157] and Muller et al. [M. Nausner, J. Schlagnitweit, V. Smrecki, X. Yang, A. Jerschow, N. Muller, J. Magn. Reson. (2009) 198(1) 73-79]. In this regard, WURST pulse sequences may afford an efficient new method for experimentally detecting impedance mismatches between receiving and excitation circuits, allowing for the optimization of solids and solution NMR and NQR spectrometer systems. The use of the Carr-Purcell Meiboom-Gill (CPMG) pulse sequence for signal enhancement of NQR spectra acquired with WURST pulses and conventional pulses is also investigated. Finally, the utility of WURST pulses for the acquisition of wideline NQR spectra is demonstrated by acquiring part of the 63/65Cu NQR spectrum of CuCN.

  16. Case Study: Writing a Journal Case Study

    ERIC Educational Resources Information Center

    Prud'homme-Genereux, Annie

    2016-01-01

    This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue describes incorporating a journal article into the classroom by first converting it into a case study.

  17. Ecological baseline studies

    NASA Technical Reports Server (NTRS)

    Vickers, D.

    1980-01-01

    Environmental studies of Merritt Island are discussed. Five areas of the island's ecology are examined. They include: a terrestrial community analyses, a plant community study, a small mammal population study, a rainfall study, and an ichthyological analyses.

  18. Mixed-radiation-field dosimetry utilizing Nuclear Quadrupole Resonance

    SciTech Connect

    Hintenlang, D.E.; Jamil, K.; Iselin, L.H.

    1992-01-01

    Radiation effects on urea, thiourea, guanidine carbonate and guanine sulfate were evaluated for both photon and neutron irradiations. Hydration of these materials typically provides a greatly increased sensitivity to both forms of radiation exposure, although not all materials lend themselves to this treatment without changing the chemical structure of the compound. Urea was found to be the most stable hydrated compound and provides the best sensitivity for quantifying radiation effects using NQR techniques. Urea permits a straight-forward quantification of each of the important parameters of the observed NQR signal, the FID. Several advanced data analysis methods were developed to assist in quantifying NQR spectra, both from urea and materials having more complex molecular structures, such as thiourea and guanidine sulfate. Unfortunately, these analysis techniques are frequently quite time consuming for the complex NQR spectra that result from some of these materials. The simpler analysis afforded by urea has therefore made it the prime candidate for an NQR dosimetry material. The moderate sensitivity of hydrated urea to photon irradiation does not permit this material to achieve the levels of performance required for a personnel dosimeter. It does, however, demonstrate acceptable sensitivity over dose ranges where it could provide a good biological dosimeter for several areas of radiation processing. The demonstrated photon sensitivity could permit hydrated urea to be used in applications such as food irradiation dosimetry. This material also exhibits a good sensitivity to neutron irradiation. The precise correlation between neutron exposure and the parameters of the resulting NQR spectra are currently being developed.

  19. Social Studies: Secondary Course of Study.

    ERIC Educational Resources Information Center

    Idaho State Dept. of Education, Boise.

    This course of study guide describes the social studies curriculum to be offered by Idaho schools for secondary students. The guide puts forth content requirements that local school districts need to meet. The following courses are covered: United States history, American government, and economics. The information for the courses includes a…

  20. German Studies in America. German Studies Notes.

    ERIC Educational Resources Information Center

    Sander, Volkmar; Osterle, Heinz D.

    This volume contains two papers, "German Studies in America," by Volkmar Sander, and "Historicism, Marxism, Structuralism: Ideas for German Culture Courses," by Heinz D. Osterle. The first paper discusses the position of German studies in the United States today. The greatest challenge comes from low enrollments; therefore, German departments must…

  1. Oxygen-17 and copper-63 NMR study of spindynamics in low- dimensional spin 1/2 antiferromagnets

    NASA Astrophysics Data System (ADS)

    Thurber, Kent Robert

    63Cu and 17O nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) experiments are reported on copper-oxide compounds related to high temperature superconductors that are nearly ideal realizations of spin 1/2 Heisenberg antiferromagnets with different geometries of the magnetic interactions: 1 dimensional spin chains, 2 dimensional planes, two coupled chains (two-leg ladder), and three coupled chains (three-leg ladder). Comparison of the spin-lattice relaxation rate, 1/T1, for 63Cu and 17O reveals the wave-vector, q, dependence of low-energy magnetic fluctuations, and 1/T2 G the Gaussian spin-spin relaxation rate provides information about the electron spin correlation length, ξ. In the 1d material, Sr 2CuO3, 171/T1(q = 0) ~ aT + bT2 over the whole temperature range 10 to 700 K. Frequency dependence measurements show that diffusive contributions dominate T1(q ~ 0) for the double chain 1d material, SrCuO2. For the undoped 2d copper oxide material, Sr2CuO2Cl2, we demonstrate that 17O 1/T1 measures the spin wave damping in the undoped antiferromagnet for short wavelengths. We find that the spin wave damping is small, clarifying one of the unique properties of these 2d copper-oxide antiferromagnetic materials: there is a wide temperature range where short range spin excitations exist with long lifetimes, without long range 3-dimensional order. The two-leg ladder materials, SrCu2O3 and A 14Cu24O41 (A = La,Sr,Ca), have a large energy gap for spin excitations. There is a crossover in magnetic fluctuations from temperatures below the spin gap to above the spin gap. For the doped two-leg ladders, the effective doping of the ladders changes with temperature, and this temperature is correlated to the magnetic spin gap energy. The three-leg ladder material, Sr2Cu3O5, demonstrates a crossover in the temperature dependence of the spin correlation length, ξ. At high temperatures, we find the ξ ~ 1/T behavior characteristic of a 1d structure (isolated three

  2. LONGITUDINAL COHORT METHODS STUDIES

    EPA Science Inventory

    Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Exposure classification for occupational studies is relatively easy compared to predicting residential childhood exposures. Recent NHEXAS (Maryland) study articl...

  3. Effectiveness of Home Study.

    ERIC Educational Resources Information Center

    Diehl, Grover E.; And Others

    Home study has enjoyed a slow but steady growth in popularity and acceptance. The growth of independent home study may be attributed to both the realities of the present educational environment and the consistently positive results of the home study method. At least one researcher has suggested that the initially slow growth of home study may have…

  4. Advanced planetary studies

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Eleven study tasks are described and key results are discussed for the following: advanced planning activity; cost estimation research; planetary missions performance handbooks-revisions; multiple discipline science assessment; asteroid workshop; galilean lander mission strategies; asteroid exploration study; ion drive transport capabilities; Mars strategy study; Venus surface sample return; and ion drive/solar sail assessment study.

  5. Southeastern Cancer Study Group: breast cancer studies

    SciTech Connect

    Smalley, R.V.; Bartolucci, A.A.; Moore, M.

    1983-12-01

    During the past 10 years, the Southeastern Cancer Study Group (SECSG) has been engaged in one major adjuvant study and three major advanced disease studies for patients with adenocarcinoma of the breast. The adjuvant study is demonstrating that six months of adjuvant CMF is the therapeutic equivalent of 12 months and that post-operative irradiation is of no added therapeutic benefit. In patients with advanced disease, a low dose 5 drug combination of CMFVP induces more objective responses than single agent 5FU, but improves survival only for those patients with liver metastases when compared to the sequential use of the same 5 single agents. The three drug combination, CAF, utilizing doxorubicin, induces more objective responses than low dose CMFVP, but it does not improve overall survival. The addition of a phase active combination, CAMELEON, (i.e., sequentially alternating therapy) of CAF has not improved the duration of disease control and survival for patients with liver metastases, lymphangitic and nodular lung metastases compared to CAF. Aggressive combination chemotherapeutic approaches to patients with advanced disease provide better and longer disease and tumor control but only marginal improvements in overall survival. Adding additional agents to a maximally tolerable regimen has not improved the therapeutic outcome.

  6. Habitat Study. Transect Study. [Environmental Education Units.

    ERIC Educational Resources Information Center

    Minneapolis Independent School District 275, Minn.

    These three documents outline teaching activities intended to involve children with their environment. Suggested preliminary studies to motivate and familiarize elementary school students with some characteristics of organisms and their physical environment are followed by descriptions of class activities that may be undertaken in the field.…

  7. Chemical Industry Bandwidth Study

    SciTech Connect

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  8. Excellence in Social Studies.

    ERIC Educational Resources Information Center

    Durfee, David A.

    1986-01-01

    Discusses a strategy for unifying and improving the social studies curriculum through an "outcomes sought" approach. Outlines eight measurable qualities students completing social studies should have achieved. Discusses implications of this approach. (LP)

  9. Case Study Teaching

    ERIC Educational Resources Information Center

    Herreid, Clyde Freeman

    2011-01-01

    This chapter describes the history of case study teaching, types of cases, and experimental data supporting their effectiveness. It also describes a model for comparing the efficacy of the various case study methods. (Contains 1 figure.)

  10. The Study of Algae

    ERIC Educational Resources Information Center

    Rushforth, Samuel R.

    1977-01-01

    Included in this introduction to the study of algae are drawings of commonly encountered freshwater algae, a summary of the importance of algae, descriptions of the seven major groups of algae, and techniques for collection and study of algae. (CS)

  11. Esophagram (Barium Swallow Study)

    MedlinePlus

    ... esophagram is a study that is completed in radiology. The test evaluates the esophagus. The esophagus is ... to wear. The study is completed in a radiology (x-ray/fluoroscopy) room. If a child is ...

  12. Chesapeake Bay study

    NASA Technical Reports Server (NTRS)

    Love, W. J.

    1972-01-01

    The objectives and scope of the Chesapeake Bay study are discussed. The physical, chemical, biological, political, and social phenomena of concern to the Chesapeake Bay area are included in the study. The construction of a model of the bay which will provide a means of accurately studying the interaction of the ecological factors is described. The application of the study by management organizations for development, enhancement, conservation, preservation, and restoration of the resources is examined.

  13. Satellite servicing economic study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Previous studies have shown that satellite servicing is cost effective; however, all of these studies were of different formats, dollar year, learning rates, availability, etc. Therefore, it was difficult to correlate any useful trends from these studies. The reviewed study was initiated to correlate the economic data into a common data base, using a common set of assumptions. A selected set of existed funded programs was then analyzed to provide an independent analysis of the servicing options and potential economic benefits.

  14. Satellite servicing economic study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Previous studies have shown that satellite servicing is cost effective; however, all of these studies were of different formats, dollar year, learning rates, availability, etc. Threfore, it was difficult to correlate any useful trends from these studies. The reviewed study was initiated to correlate the economic data into a common data base, using a common set of assumptions. A selected set of existed funded programs was then analyzed to provide an independent analysis of the servicing options and potential economic benefits.

  15. Graduate Liberal Studies.

    ERIC Educational Resources Information Center

    Brown, Peggy, Ed.

    1982-01-01

    An article on graduate liberal studies (GLS) and descriptions of GLS programs are presented. In "The Concept of Graduate Liberal Studies," Allie M. Frazier considers GLS curricular offerings, characteristics of students pursuing these studies, and the future of GLS. GLS degree programs allow adults to pursue a liberal education, which is seen as a…

  16. Cave Water Studies.

    ERIC Educational Resources Information Center

    O'Keefe, Elizabeth S.

    1996-01-01

    Describes a comparative study project where seventh grade students tested water samples from 10 cave sites that had been tested 24 years ago in a study that had attempted to determine if pollution in the environment had reached cave water. Discusses lab skills and some results of the study. (JRH)

  17. Centering on Independent Study.

    ERIC Educational Resources Information Center

    Miller, Stephanie

    Independent study is an instructional approach that can have enormous power in the classroom. It can be used successfully with students at all ability levels, even though it is often associated with gifted students. Independent study is an opportunity for students to study a subject of their own choosing under the guidance of a teacher. The…

  18. Developing Environmental Study Areas.

    ERIC Educational Resources Information Center

    Wert, Jonathan M.

    This publication is designed to help the teacher in developing environmental study areas. Numerous examples of study areas, including airports, lakes, shopping centers, and zoos, are listed. A current definition of environmental study areas is given and guidelines for their development and identification are included. The appendix, which comprises…

  19. Why Study Italian?

    ERIC Educational Resources Information Center

    Haines, Charles

    1978-01-01

    One studies Italian for the same reason one studies any language--to become educated. Even more than for art and music, Italian is necessary for literature. Dante must be read, and in the original. Further, we study Italian to know our cultural roots and heritage. (AMH)

  20. Qualitative Studies: Historiographical Antecedents.

    ERIC Educational Resources Information Center

    Mills, Rilla Dean

    This paper provides an overview of qualitative studies' antecedents among historiographers and of the positivist tide which nearly engulfed them. Humans live by interpretations. The task of social science--the basic task of qualitative studies--is to study these interpretations so that we can better understand the meanings which people use to…

  1. Defining (Conceptualizing) Social Studies.

    ERIC Educational Resources Information Center

    Shaver, James P.

    1990-01-01

    Critiques James Barth, Robert Barr, and Sam Shermis' three social studies traditions theory and National Commission on Social Studies task force report. Argues first falsely splits essential social studies components; second creates a curricular hodgepodge. Highlights need to consider values as both affective and cognitive and to create…

  2. Critical Education Studies

    ERIC Educational Resources Information Center

    Boxley, Simon

    2015-01-01

    Education Studies as an academic discipline within HE in the UK is a contested area. One thing most Education Studies programmes might agree on is that they are "critical". But what is a genuinely critical Education Studies degree? And, how could such a programme survive within the hostile neoliberal environment of the contemporary UK?…

  3. American Studies through Folktales.

    ERIC Educational Resources Information Center

    Pedersen, E. Martin

    1992-01-01

    American studies is a combination of fields such as literature, history, philosophy, politics, and economics. This publication examines how the different fields of study relate to American studies through folklore or folktales. The use of folktales can provide better illustrations and understandings of U.S. individuals' heritage and evolution.…

  4. Home Start Evaluation Study.

    ERIC Educational Resources Information Center

    High/Scope Educational Research Foundation, Ypsilanti, MI.

    Case studies of seven Home Start programs are given as the third section of an evaluation study. Communities involved are Huntsville, Alabama; Fairbanks, Alaska; Fort Defiance, Arizona; Dardanelle, Arkansas; Wichita, Kansas; Gloucester, Massachusetts; and Reno, Nevada. Although each study varies in format, each describes in detail the degree and…

  5. Jefferson Township Schools Study.

    ERIC Educational Resources Information Center

    Dayton Univ., OH. Office of Educational Services.

    This report presents a study that examines the possibility of reorganizing the Jefferson Township (Ohio) Schools' junior high and high school from their present 7-9/10-12 configuration to a 7-8/9-12 grade plan. Data for the study were gathered through 1) a facilities study of the junior high and high school to examine space availability, present…

  6. Social Psychoanalytic Disability Studies

    ERIC Educational Resources Information Center

    Goodley, Dan

    2011-01-01

    This paper explores connections and tensions between psychoanalysis and disability studies. The first part of the paper considers contemporaneous engagements with the psyche by a number of disability studies writers. These scholars have remained accountable to a politicised disability studies but have pushed for critical encounters with the…

  7. Nebraska Social Studies Statutes.

    ERIC Educational Resources Information Center

    Nebraska State Dept. of Education, Lincoln.

    This booklet lists the laws that relate to Nebraska social studies. The volume is intended for administrators, teachers, and curriculum planners to assist them to do a more thorough job of planning social studies programs. The Nebraska Social Studies Statutes are designed to be a primary tool in developing a district's curriculum, as they speak to…

  8. WISCONSIN LONGITUDINAL STUDY (WLS)

    EPA Science Inventory

    The Wisconsin Longitudinal Study (WLS) is a long-term study of a random sample of 10,317 men and women who graduated from Wisconsin high schools in 1957. The WLS provides an opportunity to study of the life course, intergenerational transfers and relationships, family functioning...

  9. Professors' Irritating Behavior Study

    ERIC Educational Resources Information Center

    Malikow, Max

    2007-01-01

    The purpose of this study was to quantify the irritating behaviors of professors as experienced and reported by 232 Le Moyne College students. In this study, "irritating behavior" was understood as "actions that vex, annoy, bother, pester, frustrate, or provoke anger." The survey used in this study was developed by Larry M. Ludewig, Ph.D.,…

  10. The Georgia Centenarian Study.

    ERIC Educational Resources Information Center

    Poon, Leonard W.; And Others

    1992-01-01

    Presents theoretical rationale, hypotheses, models, and methods and procedures of Georgia Centenarian Study, interdisciplinary study of oldest-old which began in 1988 to investigate adaptational characteristics of long-lived individuals. Introduces other articles in journal issue: first four reports of study, summarizing data collected in first…

  11. Mars Aerocapture Systems Study

    NASA Technical Reports Server (NTRS)

    Wright, Henry S.; Oh, David Y.; Westhelle, Carlos H.; Fisher, Jody L.; Dyke, R. Eric; Edquist, Karl T.; Brown, James L.; Justh, Hilary L.; Munk, Michelle M.

    2006-01-01

    Mars Aerocapture Systems Study (MASS) is a detailed study of the application of aerocapture to a large Mars robotic orbiter to assess and identify key technology gaps. This study addressed use of an Opposition class return segment for use in the Mars Sample Return architecture. Study addressed mission architecture issues as well as system design. Key trade studies focused on design of aerocapture aeroshell, spacecraft design and packaging, guidance, navigation and control with simulation, computational fluid dynamics, and thermal protection system sizing. Detailed master equipment lists are included as well as a cursory cost assessment.

  12. Advanced Clothing Studies

    NASA Technical Reports Server (NTRS)

    Orndoff, Evelyne; Poritz, Darwin

    2014-01-01

    All human space missions require significant logistical mass and volume that add an unprecedented burden on longduration missions beyond low-Earth orbit. For these missions with limited cleaning resources, a new wardrobe must be developed to reduce this logistical burden by reducing clothing mass and extending clothing wear. The present studies have been undertaken, for the first time, to measure length of wear and to assess the acceptance of such extended wear. Garments in these studies are commercially available exercise T-shirts and shorts, routine-wear T-shirts, and longsleeved pullover shirts. Fabric composition (cotton, polyester, light-weight, superfine Merino wool, modacrylic, cotton/rayon, polyester/Cocona, modacrylic/Xstatic, modacrylic/rayon, modacrylic/lyocell/aramid), construction (open knit, tight knit, open weave, tight weave), and finishing treatment (none, quaternary ammonium salt) are the independent variables. Eleven studies are reported here: five studies of exercise T-shirts, three of exercise shorts, two of routine wear Tshirts, and one of shirts used as sleep-wear. All studies are conducted in a climate-controlled environment, similar to a space vehicle's. For exercise clothing, study participants wear the garments during aerobic exercise. For routine wear clothing, study participants wear the T-shirts daily in an office or laboratory. Daily questionnaires collected data on ordinal preferences of nine sensory elements and on reason for retiring a used garment. Study 1 compares knitted cotton, polyester, and Merino exercise T-shirts (61 participants), study 2, knitted polyester, modacrylic, and polyester/Cocona exercise T-shirts (40 participants), study 3, cotton and polyester exercise shorts, knitted and woven (70 participants), all three using factorial experimental designs with and without a finishing treatment, conducted at the Johnson Space Center, sharing study participants. Study 4 compares knitted polyester and ZQ Merino exercise T

  13. Investigation of Wavelet-Based Enhancements to Nuclear Quadrupole Resonance Explosives Detectors

    SciTech Connect

    Kercel, Stephen W.; Dress, William B.; Hibbs, Andrew D.; Barrall, Geoffrey A.

    1998-06-01

    Nuclear Quadrupole Resonance (NQR) is effective for the detection and identification of certain types of explosives such as RDX, PETN and TNT. In explosive detection, the NQR response of certain 14N nuclei present in the crystalline material is probed. The 14N nuclei possess a nuclear quadrupole moment which in the presence of an electric field gradient produces an energy level splitting which may be excited by radio-frequency magnetic fields. Pulsing on the sample with a radio signal of the appropriate frequency produces a transient NQR response which may then be detected. Since the resonant frequency is dependent upon both the quadrupole moment of the 14N nucleus and the nature of the local electric field gradients, it is very compound specific. Under DARPA sponsorship, the authors are using multiresolution methods to investigate the enhancement of operation of NQR explosives detectors used for land mine detection. For this application, NQR processing time must be reduced to less than one second. False alarm responses due to acoustic and piezoelectric ringing must be suppressed. Also, as TNT is the most prevalent explosive found in land mines, NQR detection of TNT must be made practical despite unfavorable relaxation tunes. All three issues require improvement in signal-to-noise ratio, and all would benefit from improved feature extraction. This paper reports some of the insights provided by multiresolution methods that can be used to obtain these improvements. It includes results of multiresolution analysis of experimentally observed NQR signatures for RDX responses and various false alarm signatures in the absence of explosive compounds.

  14. Mysore study: A study of suicide notes

    PubMed Central

    Namratha, P.; Kishor, M.; Sathyanarayana Rao, T. S.; Raman, Rajesh

    2015-01-01

    Background: Suicide is one of the leading causes of preventable deaths. Recent data suggest South India as one of the regions with highest suicide rates in the world. In 2013, 134,799 people committed suicide in India according to the statistics released by the National Crime Records Bureau. Suicide note is one of the most important sources to understand suicide, which may be beneficial in suicide prevention. Studies on suicidal notes from this part of the world are sparse. Objective: The aim was to study the themes in suicide notes that might be useful in prevention strategies. Materials and Methods: A descriptive study of all suicide notes of those individuals who committed suicide between 2010 and 2013 available with Police Department, Mysore district was obtained and analyzed. Results: A total of 22 suicide note were available. A majority of suicide note was in age group of 16–40 years (86%) and most were men (59%). All suicide notes were handwritten, the majority (70%) in regional language Kannada. Length of notes varied from just few words to few pages. Contents of suicide notes included apology/shame/guilt (80%), love for those left behind (55%) and instruction regarding practical affairs (23%). Most have blamed none for the act (50%). 23% mentioned that they are committing suicide to prove their innocence. 32% mentioned a last wish. Conclusion: The majority of suicidal note contained “guilt” which is a strong indicator of possible depression in deceased. Creating awareness about suicide among public and ensuring access to professionals trained in suicide prevention is need of the hour in this part of the world. PMID:26816426

  15. The case study approach

    PubMed Central

    2011-01-01

    The case study approach allows in-depth, multi-faceted explorations of complex issues in their real-life settings. The value of the case study approach is well recognised in the fields of business, law and policy, but somewhat less so in health services research. Based on our experiences of conducting several health-related case studies, we reflect on the different types of case study design, the specific research questions this approach can help answer, the data sources that tend to be used, and the particular advantages and disadvantages of employing this methodological approach. The paper concludes with key pointers to aid those designing and appraising proposals for conducting case study research, and a checklist to help readers assess the quality of case study reports. PMID:21707982

  16. Teleoperator Human Factors Study

    NASA Technical Reports Server (NTRS)

    1986-01-01

    An investigation of the spectrum of space teleoperation activities likely in the 1985 to 1995 decade focused on the resolution of critical human engineering issues and characterization of the technology effect on performance of remote human operators. The study began with the identification and documentation of a set of representative reference teleoperator tasks. For each task, technology, development, and design options, issues, and alternatives that bear on human operator performance were defined and categorized. A literature survey identified existing studies of man/machine issues. For each teleoperations category, an assessment was made of the state of knowledge on a scale from adequate to void. The tests, experiments, and analyses necessary to provide the missing elements of knowledge were then defined. A limited set of tests were actually performed, including operator selection, baseline task definition, control mode study, lighting study, camera study, and preliminary time delay study.

  17. Human exploration mission studies

    NASA Technical Reports Server (NTRS)

    Cataldo, Robert L.

    1989-01-01

    The Office of Exploration has established a process whereby all NASA field centers and other NASA Headquarters offices participate in the formulation and analysis of a wide range of mission strategies. These strategies were manifested into specific scenarios or candidate case studies. The case studies provided a systematic approach into analyzing each mission element. First, each case study must address several major themes and rationale including: national pride and international prestige, advancement of scientific knowledge, a catalyst for technology, economic benefits, space enterprise, international cooperation, and education and excellence. Second, the set of candidate case studies are formulated to encompass the technology requirement limits in the life sciences, launch capabilities, space transfer, automation, and robotics in space operations, power, and propulsion. The first set of reference case studies identify three major strategies: human expeditions, science outposts, and evolutionary expansion. During the past year, four case studies were examined to explore these strategies. The expeditionary missions include the Human Expedition to Phobos and Human Expedition to Mars case studies. The Lunar Observatory and Lunar Outpost to Early Mars Evolution case studies examined the later two strategies. This set of case studies established the framework to perform detailed mission analysis and system engineering to define a host of concepts and requirements for various space systems and advanced technologies. The details of each mission are described and, specifically, the results affecting the advanced technologies required to accomplish each mission scenario are presented.

  18. Communications systems checkout study

    NASA Technical Reports Server (NTRS)

    Ginter, W. G.

    1972-01-01

    The results and conclusions of an engineering study of Space Station communications subsystem checkout are reported. The primary purpose of the study is to recommend specific guidelines and constraints for the design and utilization of the communications subsystem leading to a practical and effective means of onboard checkout implementation. Major study objectives are as follows: (1) identify candidate communications subsystem checkout concepts, (2) determine implementation impacts of feasible concepts, (3) evaluate practicality and effectiveness of alternative concepts, (4) propose baseline modifications to accommodate preferred concepts, and (5) recommend areas for additional investigation. In addition, study results are interpreted, where appropriate, in terms of their applicability to checkout of Shuttle-Orbiter communications subsystem.

  19. Research Studies & Networks

    Cancer.gov

    These epidemiological studies may assist in evaluating associations between certain pharmaceuticals and disease risk and contain detailed information on pharmaceutical use and disease risk, including cancer.

  20. Xenia Spacecraft Study

    NASA Technical Reports Server (NTRS)

    Hopkins, Randy

    2009-01-01

    This slide presentation reviews the proposed design for the Xenia mission spacecraft. The goal of this study is to perform a mission concept study for the mission. Included in this study are: the overall ground rules and assumptions (GR&A), a mission analysis, the configuration, the mass properties, the guidance, Navigation and control, the proposed avionics, the power system, the thermal protection system, the propulsion system, and the proposed structures. Conclusions from the study indicate that the observatory fits within the Falcon 9 mass and volume envelope for launching from Omelek, the pointing, slow slewing, and fast slewing requirements and the thermal requirements are met.

  1. Future Spacelift Requirements Study

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This study addresses future space applications and the derived requirements these potential applications will have on future spacelift systems. This NASA sponsored activity is a comprehensive study of potential missions including those of the military, civil, and commercial users. The study objectively evaluated the key architectural requirements for future launch systems. The results of this study are technical, economic, and policy analyses of future spacelift systems. It is intended to assist NASA and DOD decision-makers in planning technical investments and establishing policy for future U.S. spacelift systems.

  2. Access to space studies

    NASA Technical Reports Server (NTRS)

    Martin, James A.

    1993-01-01

    The National Aeronautics and Space Administration is currently considering possible directions in Earth-to-orbit vehicle development under a study called 'Access to Space.' This agency-wide study is considering commercial launch vehicles, human transportation, space station logistics, and other space transportation requirements over the next 40 years. Three options are being considered for human transportation: continued use of the Space Shuttle; development of a small personnel carrier (personnel logistics system (PLS)); or development of an advanced vehicle such as a single-stage-to-orbit (SSTO). Several studies related to the overall Access to Space study are reported in this document.

  3. Lesson Study: Beyond Coaching

    ERIC Educational Resources Information Center

    Lewis, Catherine; Perry, Rebecca; Foster, David; Hurd, Jacqueline; Fisher, Linda

    2011-01-01

    The authors assert that lesson study--a collaborative, teacher-led approach to learning from practice--offers a deeper, broader, more sustainable method of improving teacher practice than one-on-one coaching does. In lesson study, teachers and coaches of all levels of experience can work together, each bringing his or her own professional…

  4. Five year spinning study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA-ARS Cotton Quality Research Station (CQRS) has complete a comprehensive study of the relationship of cotton fiber properties to the quality of ring spun yarn. Cottons in this study demonstrated fiber quality traits that allow them to operate at high speeds on the latest generation of ring ...

  5. Library Studies I Workbook.

    ERIC Educational Resources Information Center

    Frost, William J.

    Developed for use in the Library Studies I component of the Library Studies Program at Bloomsburg University (Pennsylvania), this self-paced workbook is intended to acquaint students with the Harvey A. Andruss Library and help them develop information-seeking skills. The workbook is designed to be used in conjunction with an exercise book, and…

  6. Survey of Study Programs.

    ERIC Educational Resources Information Center

    Ellis, E. N.; Moodie, Allan G.

    This appendix contains the questionnaire, Survey of Study Programs, which was sent to the principals of the Vancouver secondary schools to determine what opportunities were provided for students to study independently. The thirteen questions are in short answer and "Yes/No" form. There is room available for comment. (See TM 000 969.) (MS)

  7. Asterisk Grade Study Report.

    ERIC Educational Resources Information Center

    Kokorsky, Eileen A.

    A study was conducted at Passaic County Community College (PCCC) to investigate the operation of a grading system which utilized an asterisk (*) grade to indicate progress in a course until a letter grade was assigned. The study sought to determine the persistence of students receiving the "*" grade, the incidence of cases of students receiving…

  8. SIAST Longitudinal Study.

    ERIC Educational Resources Information Center

    Sarkar, Gerlinde

    In 1991, the Saskatchewan Institute of Applied Science and Technology (SIAST) initiated a study of factors affecting student persistence, finding that high employment rates in particular sectors were related to higher rates of student attrition. In 1994, a follow-up study was conducted of the career/educational paths of 1,498 respondents from the…

  9. Simulation in International Studies

    ERIC Educational Resources Information Center

    Boyer, Mark A.

    2011-01-01

    Social scientists have long worked to replicate real-world phenomena in their research and teaching environments. Unlike our biophysical science colleagues, we are faced with an area of study that is not governed by the laws of physics and other more predictable relationships. As a result, social scientists, and international studies scholars more…

  10. Study Canada: International Outlook.

    ERIC Educational Resources Information Center

    Monahan, Robert L.; And Others

    This self-contained unit of study on Canada is one of a series which can be used to supplement secondary level courses of social studies, contemporary world problems, government, history, and geography. Developed by teachers, the unit focuses on international relations. A comparative approach is used which stresses understanding Canada from…

  11. COLD WEATHER PLUME STUDY

    EPA Science Inventory

    While many studies of power plant plume transport and transformation have been performed during the summer, few studies of these processes during the winter have been carried out. Accordingly, the U.S. Environmental Protection Agency and the Electric Power Research Institute join...

  12. Qualitative Studies in HRD.

    ERIC Educational Resources Information Center

    1999

    The first of the four papers in this symposium, "What Is It Like To Be an Independent HRD Consultant?" (Alexander Ardishvili), reports on a phenomenological study that investigated the experience of being an independent HRD (human resource development) consultant through interviews with 10 successful HRD consultants. The study identified eight…

  13. Contemporary American Indian Studies

    ERIC Educational Resources Information Center

    Larson, Sidner

    2009-01-01

    In his keynote address to the Fifth Annual American Indian Studies Consortium in 2005 David Wilkins began by commenting on earlier attempts to formally organize such a gathering in ways that might help establish and accredit Indian studies programs. He said he had the sense that the thrust of earlier meetings "was really an opportunity for Native…

  14. Managerial Accounting. Study Guide.

    ERIC Educational Resources Information Center

    Plachta, Leonard E.

    This self-instructional study guide is part of the materials for a college-level programmed course in managerial accounting. The study guide is intended for use by students in conjuction with a separate textbook, Horngren's "Accounting for Management Control: An Introduction," and a workbook, Curry's "Student Guide to Accounting for Management…

  15. Databases Improve Technical Studies

    ERIC Educational Resources Information Center

    Graube, Gabriele

    2004-01-01

    In Lower Saxony, technology studies as part of preparing technical education teachers for primary and partly for secondary education can be studied only at two universities--the Technical University of Brunswick and the University of Oldenburg. Technology education is not available at the Gymnasium (a type of secondary school leading to the…

  16. NACUBO Endowment Study, 1995.

    ERIC Educational Resources Information Center

    Cambridge Associates, Inc., Boston, MA.

    This report presents the results of the 1995 study of the performance and management of college and university endowments, based on 394 institutions providing data. A summary abstract provides an overview of performance and investment data; and Part 1 of the study provides a brief commentary covering endowment characteristics, historical…

  17. Brine stability study

    SciTech Connect

    Gary Garland

    2015-04-15

    This is a study of the brine formulations that we were using in our testing were stable over time. The data includes charts, as well as, all of the original data from the ICP-MS runs to complete this study.

  18. 1990 NACUBO Endowment Study.

    ERIC Educational Resources Information Center

    National Association of College and University Business Officers, Washington, DC.

    The 1990 Endowment Study of America's colleges and universities covered a broad variety of endowment issues of concern to trustees and administrators. The survey was mailed to 450 institutions and 369 institutions (82%) responded. Results of the study showed that 367 institutions had endowment assets totaling $60.1 billion. For fiscal year 1990,…

  19. MIXTURES FEASIBILITY STUDY

    EPA Science Inventory

    A number of studies have been conducted to address questions concerning the toxicity of "real world" mixtures of DBPs. These studies, which used either concentrates of drinking water or humic acid preparations treated with various disinfectants, were largely negative and had a nu...

  20. Independent Human Studies.

    ERIC Educational Resources Information Center

    Kaplan, Suzanne; Wilson, Gordon

    1978-01-01

    The Independent Human Studies program at Schoolcraft College offers an alternative method of earning academic credits. Students delineate an area of study, pose research questions, gather resources, synthesize the information, state the thesis, choose the method of presentation, set schedules, and take responsibility for meeting deadlines. (MB)

  1. Theorizing Iberian Studies

    ERIC Educational Resources Information Center

    Newcomb, Robert Patrick

    2015-01-01

    A growing number of scholars invested in Iberian Studies are asking how peninsular literary and cultural studies might be reimagined, and reinvigorated, by placing the Spanish and Portuguese canons into critical dialogue with each other, and with Galician, Catalan, Basque/Euskadi, and Latin American and North African immigrant writers, cultural…

  2. Nigerian Social Studies.

    ERIC Educational Resources Information Center

    Adeyemi, Michael B.

    1986-01-01

    Provides a brief history of Nigeria and describes the origin and development of present-day social studies instruction. Concludes that while Nigerian social studies instruction appears to be changing from the traditional passive approach to modern activity methods, instruction continues to be organized by traditional disciplines and motivated by…

  3. English Intonation Studies.

    ERIC Educational Resources Information Center

    Lewis, Jack Windsor

    This paper is a critical survey of the work of various linguists in the field of English intonation studies. Crystal's work is cited as being particularly influential in the author's work. It is argued that there is a lack of progress in this field because of a preoccupation on the part of scholars with their own studies and their application and…

  4. Cuban Studies Newsletter.

    ERIC Educational Resources Information Center

    Pittsburgh Univ., PA. University Center for International Studies.

    This is the first issue of the Cuban Studies Newsletter, a biannual publication designed to provide comprehensive and timely communication among those interested in Cuban Studies. The purpose of the newsletter stated in a recommendation by the International Conference on Cuban Bibliography and Acquisitions, April, 1970, is to promote the scholarly…

  5. [Qualitative case study].

    PubMed

    Debout, Christophe

    2016-06-01

    The qualitative case study is a research method which enables a complex phenomenon to be explored through the identification of different factors interacting with each other. The case observed is a real situation. In the field of nursing science, it may be a clinical decision-making process. The study thereby enables the patient or health professional experience to be conceptualised. PMID:27338694

  6. Study of strange nuclei

    SciTech Connect

    Chrien, R.E.

    1982-12-08

    A brief history of the discovery of hypernuclei is given and some recent hypernuclei studies are described. Topics include the study of p-shell hypernuclei, /sup 12/C (K/sup -/, ..pi../sup -/) experiment, and hypernuclear gamma rays. 13 references. (WHK)

  7. The Study of Teaching.

    ERIC Educational Resources Information Center

    Corrigan, Dean, Ed.

    This publication represents four years of work by the Commission on Implications of Recent Research on Teaching. An article by Henry Hermanowicz, "Studies of Teaching and Their Impact on Future Developments in Teacher Education," (ED 024 624) reviews recent critical examinations of teacher education, new developments in the systematic study of…

  8. International Study Tour Groups

    ERIC Educational Resources Information Center

    O'Reilly, Frances L.; Matt, John J.; McCaw, William P.; Kero, Patty; Stewart, Courtney; Haddouch, Reda

    2014-01-01

    Using the context of international study tour groups, this study examined the personal and professional transformation that occurred among host faculty and staff at The University of Montana-Missoula as a result of their interactions with traveling academics from other countries. Data were collected from participant responses (n = 27) using a…

  9. Social Studies Resource Units.

    ERIC Educational Resources Information Center

    Bemiss, Clair W.

    Based on the premise that fundamental solutions to environmental problems must include social solutions, these three resource units are designed to study the interrelation of man and nature as part of the social studies curriculum. A series of inquiry questions are posed with the intent of stimulating students to find solutions to our…

  10. Cooperative Agreements Study Report.

    ERIC Educational Resources Information Center

    Lawton, R. E.; Magruder, D.

    During the 1983 meeting of the Florida Legislature, action was taken to begin a systematic study of the level of cooperation between the Florida public schools K-12 program and the community and junior colleges. The goals and objectives of the Cooperative Agreements Study were to review and compile a list of the cooperative agreements and identify…

  11. Home Study Advertising Handbook.

    ERIC Educational Resources Information Center

    Lambert, Michael P., Ed.; Welch, Sally R., Ed.

    This handbook contains a collections of nine articles on the subject of direct-response advertising. The handbook gives advice on how to create effective advertisements for home study courses. The nine articles are the following: "Overview of Home Study Advertising in the 1990s" (Michael P. Lambert); "Ad Features that Sell" (Nancie E. Robertson);…

  12. Advanced planetary studies

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Results of planetary advanced studies and planning support are summarized. The scope of analyses includes cost estimation research, planetary mission performance, penetrator advanced studies, Mercury mission transport requirements, definition of super solar electric propulsion/solar sail mission discriminators, and advanced planning activities.

  13. STUDIES OF TROUBLESOME CHILDREN.

    ERIC Educational Resources Information Center

    STOTT, D.H.

    TWO STUDIES ARE REPORTED AND THEIR IMPLICATIONS DISCUSSED. IN THE FIRST STUDY AN ATTEMPT WAS MADE TO AVERT DELINQUENCY IN CHILDREN (AGED 12 AND 13) BY IDENTIFYING THE DELINQUENCY PRONE AND TREATING A PORTION OF THEM BY FAMILY CASEWORK METHODS. THROUGH USE OF THE DELINQUENCY PREDICTION INSTRUMENT AND THE BRISTOL SOCIAL ADJUSTMENT GUIDES, 33…

  14. Interagency Depainting Study Status

    NASA Technical Reports Server (NTRS)

    Clark-Ingram, Marceia; Cook, Beth

    1999-01-01

    This document discusses coating removal in general. Sections of this presentation include: regulatory background, the initial parameters of the study, the current parameters of the study, stages in each sequence, preparation of the test specimen, material evaluation testing, chemical stripping, CO2 blasting, Flashjet coating removal, plastic media blasting, sodium bicarbonate wet stripping, water stripping, and wheat starch stripping.

  15. Energy conversion alternatives study

    NASA Technical Reports Server (NTRS)

    Shure, L. T.

    1979-01-01

    Comparison of coal based energy systems is given. Study identifies and compares various advanced energy conversion systems using coal or coal derived fuels for baselaoad electric power generation. Energy Conversion Alternatives Study (ECAS) reports provede government, industry, and general public with technically consistent basis for comparison of system's options of interest for fossilfired electric-utility application.

  16. Spacing Studies in Peppers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Higher plant stand densities usually result in greater pepper fruit yields. While the impact of stand density on yield has been studied for bell and non-bell peppers, but very little information exists regarding implications on pesticide efficacy. The objective of these studies was to determine th...

  17. TOTAL DIET STUDY

    EPA Science Inventory

    The Total Diet Study (TDS), sometimes called the Market Basket Study, is an ongoing FDA program that determines levels of various pesticide residues, contaminants, and nutrients in foods, for the purpose of estimating intakes of these substances in representative diets of specifi...

  18. Social Studies. Chapter Nineteen.

    ERIC Educational Resources Information Center

    Lussie, Rick; Stradley, Mary

    Methods are examined for developing an instructional program in social studies for students with mental disabilities. A natural arena for teaching social studies--the community--provides a setting where basic skills can be applied to increase students' knowledge of the social, economic, and political environments in which they will be…

  19. Censorship in Social Studies.

    ERIC Educational Resources Information Center

    Seiferth, Berniece B.

    In order to determine how much censorship was taking place in Illinois social studies classes, 200 principals were asked to respond to a questionnaire regarding censorship of teaching methods and social studies textbooks. The principals were asked to respond to the following topics concerning the degree of censorship encountered for each item:…

  20. SETDA Case Studies 2012

    ERIC Educational Resources Information Center

    State Educational Technology Directors Association, 2012

    2012-01-01

    The State Educational Technology Directors Association (SETDA) published a series of case studies from 28 states to showcase examples of how ARRA EETT ("American Recovery and Reinvestment Act of 2009 Enhancing Education Through Technology") grant funds have impacted teaching and learning. SETDA collected data for the case studies through a variety…

  1. Geysers reservoir studies

    SciTech Connect

    Bodvarsson, G.S.; Lippmann, M.J.; Pruess, K.

    1993-04-01

    LBL is conducting several research projects related to issues of interest to The Geysers operators, including those that deal with understanding the nature of vapor-dominated systems, measuring or inferring reservoir processes and parameters, and studying the effects of liquid injection. All of these topics are directly or indirectly relevant to the development of reservoir strategies aimed at stabilizing or increasing production rates of non-corrosive steam, low in non-condensable gases. Only reservoir engineering studies will be described here, since microearthquake and geochemical projects carried out by LBL or its contractors are discussed in accompanying papers. Three reservoir engineering studies will be described in some detail, that is: (a) Modeling studies of heat transfer and phase distribution in two-phase geothermal reservoirs; (b) Numerical modeling studies of Geysers injection experiments; and (c) Development of a dual-porosity model to calculate mass flow between rock matrix blocks and neighboring fractures.

  2. Proton dynamics in the strong chelate hydrogen bond of crystalline picolinic acid N-oxide. A new computational approach and infrared, raman and INS study.

    PubMed

    Stare, Jernej; Panek, Jarosław; Eckert, Juergen; Grdadolnik, Joze; Mavri, Janez; Hadzi, Dusan

    2008-02-21

    Infrared, Raman and INS spectra of picolinic acid N-oxide (PANO) were recorded and examined for the location of the hydronic modes, particularly O-H stretching and COH bending. PANO is representative of strong chelate hydrogen bonds (H-bonds) with its short O...O distance (2.425 A). H-bonding is possibly well-characterized by diffraction, NMR and NQR data and calculated potential energy functions. The analysis of the spectra is assisted by DFT frequency calculations both in the gas phase and in the solid state. The Car-Parrinello quantum mechanical solid-state method is also used for the proton dynamics simulation; it shows the hydron to be located about 99% of time in the energy minimum near the carboxylic oxygen; jumps to the N-O acceptor are rare. The infrared spectrum excels by an extended absorption (Zundel's continuum) interrupted by numerous Evans transmissions. The model proton potential functions on which the theories of continuum formation are based do not correspond to the experimental and computed characteristics of the hydrogen bond in PANO, therefore a novel approach has been developed; it is based on crystal dynamics driven hydronium potential fluctuation. The envelope of one hundred 0 --> 1 OH stretching transitions generated by molecular dynamics simulation exhibits a maximum at 1400 cm-1 and a minor hump at approximately 1600 cm-1. These positions square well with ones predicted for the COH bending and OH stretching frequencies derived from various one- and two-dimensional model potentials. The coincidences with experimental features have to be considered with caution because the CPMD transition envelope is based solely on the OH stretching coordinate while the observed infrared bands correspond to heavily mixed modes as was previously shown by the normal coordinate analysis of the IR spectrum of argon matrix isolated PANO, the present CPMD frequency calculation and the empirical analysis of spectra. The experimental infrared spectra show some

  3. Effective Physics Study Habits

    NASA Astrophysics Data System (ADS)

    Zettili, Nouredine

    2011-04-01

    We discuss the methods of efficient study habits and how they can be used by students to help them improve learning physics. In particular, we deal with ideas pertaining to the most effective techniques needed to help students improve their physics study skills. These ideas were developed as part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), an outreach grant funded by the Alabama Commission on Higher Education. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. In the presentation, focus on topics such as the skills of how to develop long term memory, how to improve concentration power, how to take class notes, how to prepare for and take exams, how to study scientific subjects such as physics. We argue that the student who conscientiously uses the methods of efficient study habits will be able to achieve higher results than the student who does not; moreover, a student equipped with the proper study skills will spend much less time to learn a subject than a student who has no good study habits. The underlying issue here is not the quantity of time allocated to the study efforts by the student, but the efficiency and quality of actions. This work is supported by the Alabama Commission on Higher Education as part of IMPACTSEED grant.

  4. Molecular photoionization studies

    SciTech Connect

    Dehmer, P.M.

    1983-01-01

    This program is concerned with the study of the electronic structure of small molecules and clusters of molecules. Of particular interest is the interaction of discrete electronic states with one another and with the various ionization and dissociation continua. Since the Second Annual Meeting of the DOE-OHER Program on The Physics and Chemistry of Energy-Related Atmospheric Pollutants in April 1981, significant progress has been made in the following areas: (1) the study of the electronic structure of dimers and small clusters of rare gas atoms using photoionization techniques; (2) similar studies on clusters of CO/sub 2/ molecules; (3) the study of electronic structure of rare gas dimers and trimers using photoelectron and photoelectron-photoion coincidence techniques; (4) the investigation of the relationship between Rydberg states in atoms, van der Waals molecules, and chemically-bonded molecules; (5) the extension of the study of photoabsorption, photoionization, and predissociation processes in H/sub 2/ to the unsymmetric isotope HD; (6) the study of photoelectron spectra of H/sub 2/ and C/sub 2/H/sub 2/; (7) a review of some of the aspects of dissociation processes in small molecules; and (8) the creation of a new program to study the spectra and dynamics of the photoionization processes in small molecules using the technique of multiphoton ionization followed by mass and electron energy analysis of the product ions and electrons. Some of the highlights of this work are reviewed.

  5. F-14 modeling study

    NASA Technical Reports Server (NTRS)

    Levison, William H.

    1988-01-01

    This study explored application of a closed loop pilot/simulator model to the analysis of some simulator fidelity issues. The model was applied to two data bases: (1) a NASA ground based simulation of an air-to-air tracking task in which nonvisual cueing devices were explored, and (2) a ground based and inflight study performed by the Calspan Corporation to explore the effects of simulator delay on attitude tracking performance. The model predicted the major performance trends obtained in both studies. A combined analytical and experimental procedure for exploring simulator fidelity issues is outlined.

  6. Decontamination solution development studies

    SciTech Connect

    Allen, R.P.; Fetrow, L.K.; Kjarmo, H.E.; Pool, K.H.

    1993-09-01

    This study was conducted for the Westinghouse Hanford Company (WHC) by Pacific Northwest Laboratory (PNL) as part of the Hanford Grout Technology Program (HGTP). The objective of this study was to identify decontamination solutions capable of removing radioactive contaminants and grout from the Grout Treatment Facility (GTF) process equipment and to determine the impact of these solutions on equipment components and disposal options. The reference grout used in this study was prepared with simulated double-shell slurry feed (DSSF) and a dry blend consisting of 40 wt % limestone flour, 28 wt % blast furnace slag, 28 wt % fly ash, and 4 wt % type I/II Portland cement.

  7. Variability study for saltstone

    SciTech Connect

    Harbour, J. R.; Edwards, T. B.; Hansen, E. K.; Williams, V. J.

    2005-10-01

    This report is a summary of the bench-scale experimental studies performed by the Savannah River National Laboratory (SRNL) for Waste Solidification Engineering (WSE) to establish the viability of a grout-based variability study. In order for a variability study to be useful, the property measurements of the fresh and cured Saltstone must be reproducible with an inherent variation that is small compared to the changes in the properties measured over the expected range of variability for a Salt Batch. This scoping task addressed the issue of reproducibility for Saltstone.

  8. Nuclear material shipment study

    SciTech Connect

    Shepherd, E.W.

    1980-01-01

    The Radioactive Material Transport Assessment Study is expected to provide a flexible set of capabilities and useful information to the public, industry and government users by using a system design to assure obtaining high quality data from selected industry sources at acceptable cost. It is expected that the shipping record approach coupled with an efficient sampling strategy will accomplish this. The study is also designed to yield analytical capabilities and statistical output to serve public, industry and government users. The information provided by the study will make a valuable contribution to environmental and accident risk assessment, policy development and operational planning and management activities.

  9. Schoolground Soil Studies.

    ERIC Educational Resources Information Center

    Doyle, Charles

    1978-01-01

    Outlined are simple activities for studying soil, which can be conducted in the schoolyard. Concepts include soil profiles, topsoil, soil sizes, making soil, erosion, slope, and water absorption. (SJL)

  10. Electrophysiology Studies (EPS)

    MedlinePlus

    ... you need medicine, a pacemaker , an implantable cardioverter defibrillator (ICD) , cardiac ablation or surgery. These studies take ... catheter ablation . If a pacemaker or implantable cardioverter defibrillator (ICD) might help you. If you are at ...

  11. What Are Sleep Studies?

    MedlinePlus

    ... August 19, 2014 Gary H. Gibbons Why Do Fruit Flies Take Naps? NHLBI Investigator Studies Connections Between Sleep Patterns and Gene Networks in Fruit Flies Read all Director's Messages Twitter Facebook YouTube Google+ ...

  12. Building an Integrated Study

    ERIC Educational Resources Information Center

    Collins, Myrtle T.; Greenberg, Marvin

    1974-01-01

    Article described a plan to develop integrated study through music activities. Students learned to become more independent learners while concentrating on more complex and creative activities. (Author/RK)

  13. Habitability study shuttle orbiter

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Studies of the habitability of the space shuttle orbiter are briefly summarized. Selected illustrations and descriptions are presented for: crew compartment, hygiene facilities, food system and galley, and storage systems.

  14. American Studies in Britain

    ERIC Educational Resources Information Center

    Avery, Roy

    1976-01-01

    American studies in British schools touch on issues like democracy in political theory and practice, war and peace, race relations, the situations and feelings of the adolescent. Considers the implications for educational standards in Great Britain. (Author/RK)

  15. ADVANCED CUTTINGS TRANSPORT STUDY

    SciTech Connect

    Ergun Kuru; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Len Volk; Mark Pickell; Evren Ozbayoglu; Barkim Demirdal; Paco Vieira; Affonso Lourenco

    1999-10-15

    This report includes a review of the progress made in ACTF Flow Loop development and research during 90 days pre-award period (May 15-July 14, 1999) and the following three months after the project approval date (July15-October 15, 1999) The report presents information on the following specific subjects; (a) Progress in Advanced Cuttings Transport Facility design and development, (b) Progress report on the research project ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (c) Progress report on the research project ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (d) Progress report on the research project ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (e) Progress report on the research project ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Progress report on the instrumentation tasks (Tasks 11 and 12) (g) Activities towards technology transfer and developing contacts with oil and service company members.

  16. Current Research Studies

    MedlinePlus

    ... generation of massively parallel DNA sequencers and sophisticated computational methods, the initiative studies the complex role that ... complications of severe disease. CCFA’s Professional KIIDS Pediatric Network is committed to identifying the genetic, microbiological, and ...

  17. LANL Studies Earth's Magnetosphere

    ScienceCinema

    Daughton, Bill

    2014-08-12

    A new 3-D supercomputer model presents a new theory of how magnetic reconnection works in high-temperature plasmas. This Los Alamos National Laboratory research supports an upcoming NASA mission to study Earth's magnetosphere in greater detail than ever.

  18. MULTIPLE CONTAMINANTS CASE STUDIES

    EPA Science Inventory

    The presentation provides information taken from the arsenic demonstration program projects that have treatment systems removing multiply contaminants from drinking water. The case studies sited in the presentation consist of projects that have arsenic along with either nitrate, ...

  19. Methods of Studying Persons.

    ERIC Educational Resources Information Center

    Heinemann, Allen W.; Shontz, Franklin C.

    1985-01-01

    Describes a method that permits answering research questions of general importance by examining individuals in a comprehensive, whole-person manner. Discusses their use in two studies of persons with spinal cord injuries. (LLL)

  20. LIMB PROCESS DEVELOPMENT STUDIES

    EPA Science Inventory

    The report covers basic and applied studies concerned with three Limestone Injection Multistage Burner (LIMB) process objectives: (1) avoiding degradation of collection efficiency in the electrostatic precipitator (ESP) during LIMB, (2) achieving satisfactory sulfur dioxide (SO2)...

  1. Applied Research Study

    NASA Technical Reports Server (NTRS)

    Leach, Ronald J.

    1997-01-01

    The purpose of this project was to study the feasibility of reusing major components of a software system that had been used to control the operations of a spacecraft launched in the 1980s. The study was done in the context of a ground data processing system that was to be rehosted from a large mainframe to an inexpensive workstation. The study concluded that a systematic approach using inexpensive tools could aid in the reengineering process by identifying a set of certified reusable components. The study also developed procedures for determining duplicate versions of software, which were created because of inadequate naming conventions. Such procedures reduced reengineering costs by approximately 19.4 percent.

  2. Study the Problem.

    ERIC Educational Resources Information Center

    Choate, Joyce S.

    1990-01-01

    The initial step of a strategic process for solving mathematical problems, "studying the question," is discussed. A lesson plan for teaching students to identify and revise arithmetic problems is presented, involving directed instruction and supervised practice. (JDD)

  3. Intracardiac electrophysiology study (EPS)

    MedlinePlus

    ... called catheter ablation ) Watch this video about: Cardiac conduction system How to Prepare for the Test You ... study - intracardiac; EPS - intracardiac Images Heart, front view Conduction system of the heart References Miller JM, Zipes ...

  4. Rotorcraft convertible engine study

    NASA Technical Reports Server (NTRS)

    Gill, J. C.; Earle, R. V.; Mar, H. M.

    1982-01-01

    The objective of the Rotorcraft Convertible Engine Study was to define future research and technology effort required for commercial development by 1988 of convertible fan/shaft gas turbine engines for unconventional rotorcraft transports. Two rotorcraft and their respective missions were defined: a Fold Tilt Rotor aircraft and an Advancing Blade Concept (ABC) rotorcraft. Sensitivity studies were conducted with these rotorcraft to determine parametrically the influence of propulsion characteristics on aircraft size, mission fuel requirements, and direct operating costs (DOC). The two rotorcraft were flown with conventional propulsion systems (separate lift/cruise engines) and with convertible propulsion systems to determine the benefits to be derived from convertible engines. Trade-off studies were conducted to determine the optimum engine cycle and staging arrangement for a convertible engine. Advanced technology options applicable to convertible engines were studied. Research and technology programs were identified which would ensure technology readiness for commercial development of convertible engines by 1988.

  5. The Study of Matter.

    ERIC Educational Resources Information Center

    Campbell, Peter

    2000-01-01

    Reviews the booklet "The Study of Matter" produced by the Institute of Physics as part of their Shaping the Future series. This booklet is designed for teachers of chemistry, physics, design and technology, and biology. (Author/CCM)

  6. Exploratory studies, 1988

    SciTech Connect

    Not Available

    1989-05-01

    This report discusses the following topics: accelerator physics for the ALS; SSC support; machine investigations; mathematical techniques in particle dynamics; APIARY: B-factory studies; and two-beam accelerators and bright electron sources.

  7. Studies in Aeolian geology

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1988-01-01

    The objective of the research was to assess the significance of aeolian (windblown) processes in the evolution of planetary surfaces. The approach was to use wind tunnel simulations, field studies of possible analogs, and analyses of spacecraft data.

  8. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    Variable Gravity Laboratory studies are discussed. The following subject areas are covered: (1) conceptual design and engineering analysis; (2) control strategies (fast crawling maneuvers, main perturbations and their effect upon the acceleration level); and (3) technology requirements.

  9. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    Tethered gravity laboratories study is presented. The following subject areas are covered: variable gravity laboratory; attitude tether stabilizer; configuration analysis (AIT); dynamic analysis (SAO); and work planned for the next reporting period.

  10. Nature Study Tips. Spiders.

    ERIC Educational Resources Information Center

    Mulaik, Stanley B.

    1990-01-01

    Different types of spiders, their ranges and habits are discussed. Activities associated with the study of spiders are suggested. Four references are listed which may be of interest to beginners. (CW)

  11. Wilson Cycle studies

    NASA Technical Reports Server (NTRS)

    Burke, Kevin

    1987-01-01

    Regional lineaments in continental evolution were studied. It was concluded that lineaments within continents are attributed to a small number of processes of continent formation and modification, but interactions among these processes may produce complex patterns.

  12. Accelerator research studies

    SciTech Connect

    Not Available

    1992-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.

  13. Laos case study

    PubMed Central

    2012-01-01

    Peuan Mit is a Lao organization working to address the needs of children and youth living and working on the streets. This case study outlines how a trusted and strong relationship with local police provides mutual benefit. PMID:22769869

  14. Videofluoroscopic Swallowing Study (VFSS)

    MedlinePlus

    ... hear are: videofluoroscopic swallowing study, or videofluoroscopy modified barium swallow, or MBS esophagram cookie swallow The American ... give you different foods and drinks mixed with barium. The barium makes the food and liquid show ...

  15. River Meander Studies

    NASA Technical Reports Server (NTRS)

    Lingenfelter, R. E.

    1972-01-01

    The meander patterns of the Feather and Colorado rivers were studied in an attempt to correlate pattern changes and flood probability. Attempts were also made to correlate stream meander power spectrum and stream discharge frequency distribution.

  16. LANL Studies Earth's Magnetosphere

    SciTech Connect

    Daughton, Bill

    2011-04-15

    A new 3-D supercomputer model presents a new theory of how magnetic reconnection works in high-temperature plasmas. This Los Alamos National Laboratory research supports an upcoming NASA mission to study Earth's magnetosphere in greater detail than ever.

  17. Sturgeon study - specimens needed

    SciTech Connect

    Snyder, D.E.; Matthews, R.A.

    1983-01-01

    Preliminary results of a study to determine morphological criteria and verify those already suggested in the published literature for identifying the larvae of the Atlantic sturgeon and the endangered short nose sturgeon are presented. (ACR)

  18. Operator Certification Study Guide.

    ERIC Educational Resources Information Center

    American Water Works Association, Denver, CO.

    This study guide contains typical questions and answers that all levels of water treatment plant operators might expect to find on a certification examination. The manual covers the basic sciences, treatment techniques, testing procedures, and federal legislation. (Author/SB)

  19. The Black Studies Boondoggle

    ERIC Educational Resources Information Center

    Long, Richard A.

    1970-01-01

    Indicates tendencies dangerous to the basic purpose of Black Studies, and identifies four external challeges--imperialism, paternalism, nihilism, and materialism. An internal challenge is considered to be the use of European and Establishment constructs to analyze black reality. (DM)

  20. PPB | Study Team

    Cancer.gov

    The Pleuropulmonary Blastoma (PPB) DICER1 Syndrome Study team is made up of researchers from the National Cancer Institute, Children¹s National Medical Center, the International Pleuropulmonary Blastoma Registry, and Washington University in St. Louis.

  1. Agricultural Health Study

    Cancer.gov

    A prospective cohort study of commercial pesticide applicators, farmers and farmers' spouses in Iowa and North Carolina conducted in collaboration between the NIH and the U.S. Evironmental Protection Agency

  2. HYDROGEOLOGIC CASE STUDIES

    EPA Science Inventory

    Hydrogeology is the foundation of subsurface site characterization for evaluations of monitored natural attenuation (MNA). Three case studies are presented. Examples of the potentially detrimental effects of drilling additives on ground-water samples from monitoring wells are d...

  3. Earth study from space

    NASA Technical Reports Server (NTRS)

    Sidorenko, A. V.

    1981-01-01

    The significance that space studies are making to all Earth sciences in the areas of geography, geodesy, cartography, geology, meteorology, oceanology, agronomy, and ecology is discussed. It is predicted that cosmonautics will result in a revolution in science and technology.

  4. Accelerator research studies

    SciTech Connect

    Not Available

    1993-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the second year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' (P.I., M. Reiser); TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' (Co-P.I.'s, W.W. Destler, M. Reiser, M.J. Rhee, and C.D. Striffler); TASK C, Study of a Gyroklystron High-Power Microwave Source for Linear Colliders,'' (Co-P.I.'s, V.L. Granatstein, W. Lawson, M. Reiser, and C.D. Striffler). In this report we document the progress that has been made during the past year for each of the three tasks.

  5. Comparative Packaging Study

    NASA Technical Reports Server (NTRS)

    Perchonok, Michele; Antonini, David

    2008-01-01

    This viewgraph presentation describes a comparative packaging study for use on long duration space missions. The topics include: 1) Purpose; 2) Deliverables; 3) Food Sample Selection; 4) Experimental Design Matrix; 5) Permeation Rate Comparison; and 6) Packaging Material Information.

  6. Constellation Commodities Studies Summary

    NASA Technical Reports Server (NTRS)

    Dirschka, Eric

    2011-01-01

    Constellation program was NASA's long-term program for space exploration. The goal of the commodities studies was to solicit industry expertise in production, storage, and transportation required for future use and to improve efficiency and life cycle cost over legacy methods. Objectives were to consolidate KSC, CCAFS and other requirements; extract available industry expertise; identify commercial opportunities; and establish synergy with State of Florida partnerships. Study results are reviewed.

  7. Vitrification melter study

    SciTech Connect

    Jones, J.A.

    1995-04-01

    This report presents the results of a study performed to identify the most promising vitrification melter technologies that the Department of Energy (EM-50) might pursue with available funding. The primary focus was on plasma arc systems and graphite arc melters. The study was also intended to assist EM-50 in evaluating competing technologies, formulating effective technology strategy, developing focused technology development projects, and directing the work of contractors involved in vitrification melter development.

  8. Advanced planetary studies

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Results of planetary advanced studies and planning support provided by Science Applications, Inc. staff members to Earth and Planetary Exploration Division, OSSA/NASA, for the period 1 February 1981 to 30 April 1982 are summarized. The scope of analyses includes cost estimation, planetary missions performance, solar system exploration committee support, Mars program planning, Galilean satellite mission concepts, and advanced propulsion data base. The work covers 80 man-months of research. Study reports and related publications are included in a bibliography section.

  9. Tethered subsatellite study

    NASA Technical Reports Server (NTRS)

    Baker, W. P.; Dunkin, J. A.; Galaboff, Z. J.; Johnston, K. D.; Kissel, R. R.; Rheinfurth, M. H.; Siebel, M. P. L.

    1976-01-01

    The results are presented of studies performed relating to the feasibility of deploying a subsatellite from the shuttle by means of a tether. The dynamics, the control laws, the aerodynamics, the heating, and some communication considerations of the tethered subsatellite system are considered. Nothing was found that prohibits the use of a subsatellite joined to the shuttle by a long (100 km) tether. More detailed studies directed at specific applications are recommended.

  10. Cholera studies*†

    PubMed Central

    Pollitzer, R.

    1955-01-01

    In this study, the author describes in detail experimental cholera infection of mammals (infection by the oral route, intragastric inoculation, and intestinal, gall-bladder, and parenteral infection). The pathogenicity for lower animals is examined, and certain observations on insects are included. The second part of the study is devoted to the pathology of human cholera (morbid anatomy distribution of the causative organisms in the dead bodies of cholera victims, and pathogenesis). PMID:13284569

  11. Salary Study, 1999.

    ERIC Educational Resources Information Center

    Feagans, Laura

    This report details a study of trends in the salaries of Chief Executive Officers (CEOs) and other personnel at member agencies of the Child Welfare League of America (CWLA). Responding to the study's mail survey were 437 out of 977 CEOs (44.7 percent) and 337 out of 825 CWLA member agencies (40.8 percent). The bulk of the report is comprised of…

  12. Power subsystem automation study

    NASA Technical Reports Server (NTRS)

    Tietz, J. C.; Sewy, D.; Pickering, C.; Sauers, R.

    1984-01-01

    The purpose of the phase 2 of the power subsystem automation study was to demonstrate the feasibility of using computer software to manage an aspect of the electrical power subsystem on a space station. The state of the art in expert systems software was investigated in this study. This effort resulted in the demonstration of prototype expert system software for managing one aspect of a simulated space station power subsystem.

  13. Workshop I: Gender Studies

    NASA Astrophysics Data System (ADS)

    Hennessey, Eden; Kurup, Anitha; Meza-Montes, Lilia; Shastri, Prajval; Ghose, Shohini

    2015-12-01

    Participants in the Gender Studies workshop of the 5th IUPAP International Conference on Women in Physics discussed the gender question in science practice from a policy perspective, informed by investigations from the social science disciplines. The workshop's three sessions—"Equity and Education: Examining Gender Stigma in Science," "A Comparative Study of Women Scientists and Engineers: Experiences in India and the US," and "Toward Gender Equity Through Policy: Characterizing the Social Impact of Interventions—are summarized, and the resulting recommendations presented.

  14. The Agricultural Health Study.

    PubMed Central

    Alavanja, M C; Sandler, D P; McMaster, S B; Zahm, S H; McDonnell, C J; Lynch, C F; Pennybacker, M; Rothman, N; Dosemeci, M; Bond, A E; Blair, A

    1996-01-01

    The Agricultural Health Study, a large prospective cohort study has been initiated in North Carolina and Iowa. The objectives of this study are to: 1) identify and quantify cancer risks among men, women, whites, and minorities associated with direct exposure to pesticides and other agricultural agents; 2) evaluate noncancer health risks including neurotoxicity reproductive effects, immunologic effects, nonmalignant respiratory disease, kidney disease, and growth and development among children; 3) evaluate disease risks among spouses and children of farmers that may arise from direct contact with pesticides and agricultural chemicals used in the home lawns and gardens, and from indirect contact, such as spray drift, laundering work clothes, or contaminated food or water; 4) assess current and past occupational and nonoccupational agricultural exposures using periodic interviews and environmental and biologic monitoring; 5) study the relationship between agricultural exposures, biomarkers of exposure, biologic effect, and genetic susceptibility factors relevant to carcinogenesis; and 6) identify and quantify cancer and other disease risks associated with lifestyle factors such as diet, cooking practices, physical activity, smoking and alcohol consumption, and hair dye use. In the first year of a 3-year enrollment period, 26,235 people have been enrolled in the study, including 19,776 registered pesticide applicators and 6,459 spouses of registered farmer applicators. It is estimated that when the total cohort is assembled in 1997 it will include approximately 75,000 adult study subjects. Farmers, the largest group of registered pesticide applicators comprise 77% of the target population enrolled in the study. This experience compares favorably with enrollment rates of previous prospective studies. Images Figure 1. Figure 2. Figure 3. Figure 4. PMID:8732939

  15. NASA Propagation Studies Website

    NASA Technical Reports Server (NTRS)

    Angkasa, Krisjani S.

    1996-01-01

    The NASA propagation studies objective is to enable the development of new commercial satellite communication systems and services by providing timely data and models about propagation of satellite radio signals through the intervening environment and to support NASA missions. In partnership with industry and academia, the program leverages unique NASA assets (currently Advanced Communications Technology Satellite) to obtain propagation data. The findings of the study are disseminated through referred journals, NASA reference publications, workshops, electronic media, and direct interface with industry.

  16. Laboratory microfusion capability study

    NASA Astrophysics Data System (ADS)

    1993-05-01

    The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility; and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options: the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase 2 study are described in the present report.

  17. Partial gravity habitat study

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Lorandos, Jason; Akhidime, Eval; Bunch, Michael; Lund, Denise; Moore, Nathan; Murakawa, Kiosuke

    1989-01-01

    The purpose of this study is to investigate comprehensive design requirements associated with designing habitats for humans in a partial gravity environment, then to apply them to a lunar base design. Other potential sites for application include planetary surfaces such as Mars, variable-gravity research facilities, and a rotating spacecraft. Design requirements for partial gravity environments include locomotion changes in less than normal earth gravity; facility design issues, such as interior configuration, module diameter, and geometry; and volumetric requirements based on the previous as well as psychological issues involved in prolonged isolation. For application to a lunar base, it is necessary to study the exterior architecture and configuration to insure optimum circulation patterns while providing dual egress; radiation protection issues are addressed to provide a safe and healthy environment for the crew; and finally, the overall site is studied to locate all associated facilities in context with the habitat. Mission planning is not the purpose of this study; therefore, a Lockheed scenario is used as an outline for the lunar base application, which is then modified to meet the project needs. The goal of this report is to formulate facts on human reactions to partial gravity environments, derive design requirements based on these facts, and apply the requirements to a partial gravity situation which, for this study, was a lunar base.

  18. ADVANCED CUTTINGS TRANSPORT STUDY

    SciTech Connect

    Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira; Lei Zhou

    2000-01-30

    This is the second quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between Oct 1, 2000 and December 31, 2000. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 2: Addition of a foam generation and breaker system), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (d) Research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (e) Research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Research on instrumentation tasks to measure: Cuttings concentration and distribution in a flowing slurry (Task 11), and Foam properties while transporting cuttings. (Task 12), (h) Development of a Safety program for the ACTS Flow Loop. Progress on a comprehensive safety review of all flow-loop components and operational procedures. (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members. The tasks Completed During This Quarter are Task 7 and Task 8.

  19. Study downplays health concerns

    SciTech Connect

    Stringer, J.

    1996-03-13

    A government-funded study has concluded that reformulated gasoline containing methyl tert-butyl ether (MTBE) does not increase short-term health risks when compared with gasoline that does not contain the additive. The study, performed by the Health Effects Institute (Cambridge, MA), compared data from dozens of animal, human, and epidemiological studies of health effects linked to oxygenates, including MTBE and ethanol, but did not find enough evidence to warrant an immediate reduction in oxygenate use. However, the study did recommend that additional research be conducted on possible health consequences associated with the gasoline additives, including neurotoxic effects, if oxygenates continue to be used long term. Oxygenates have been used in gasoline since 1992, when EPA mandated that several municipalities use MTBE or other oxygenates in reformulated gasoline to reduce carbon monoxide emissions and meet Clean Air Act requirements. Shortly after the program began, residents in areas where the oxygenates were used complained of nausea, headaches, and dizziness. The institute says the study--funded by EPA and the Centers for Disease Control--will be used for a broader review of gasoline oxygenates by the White House Office of Science and Technology Policy.

  20. ADVANCED CUTTINGS TRANSPORT STUDY

    SciTech Connect

    Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira

    2000-10-30

    This is the first quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between July 14, 2000 and September 30, 2000. This report presents information on the following specific tasks: (a) Progress in Advanced Cuttings Transport Facility design and development (Task 2), (b) Progress on research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (c) Progress on research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (d) Progress on research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (e) Progress on research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Initiate research on project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Progress on instrumentation tasks to measure: Cuttings concentration and distribution (Tasks 11), and Foam properties (Task 12), (h) Initiate a comprehensive safety review of all flow-loop components and operational procedures. Since the previous Task 1 has been completed, we will now designate this new task as: (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members.

  1. Wilson Cycle studies

    NASA Technical Reports Server (NTRS)

    Burke, Kevin

    1987-01-01

    The main activity relating to the study during this half year was a three week field trip to study Chinese sedimentary basins (June 10 to July 3, 1986) at no cost to the project. This study, while of a reconnaissance character, permitted progress in understanding how the processes of island arc-collision and micro-continental collision operated during the Paleozoic in far western China (especially the Junggar and Tarim basins and in the intervening Tien Shan Mountains). These effects of the continuing collision of India and Asia on the area were also studied. Most specifically, these result in the elevation of the Tien Shan to more than 4 km above sea level and the depression of Turfan to move 150m below sea level. Both thrusting and large-scale strike-slip motion are important in producing these elevation changes. Some effort during the half year was also devoted to the study of greenstone-belts in terms of the Wilson Cycle.

  2. Studies In Planetary Volcanology

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    2002-01-01

    Modeling and field studies of the potential for flowing lavas to erode the terrain over which they pass: this study involved numerical solutions for the heat transfer, and analysis of lava flows on Earth where erosion appears to have taken place, coupled with observations of active flows in Hawaii. The conclusion is that some basaltic lava flows are capable of both thermal erosion (melting) and mechanical erosion, depending on the composition and structure of the pre-flow terrain. The case of high-temperature komatiite flows was also considered, especially as a potential analog for some of the flows on the moon of Jupiter, Io. 2. Application of modeling studies and field investigations to extraterrestrial cases: this aspect involved an analysis of lava flows on the Moon, considerations of the 1997 eruption observed via spacecraft (Galileo) on to, and a general review of volcanism on Mars. 3. Considerations of the interaction of lava flows and water: this aspect of the investigation involved a numerical analysis and incorporation of field studies in Iceland where such features occur; the final part of this study was to apply the results to Mars.

  3. Photovoltaics information user study

    SciTech Connect

    Belew, W.W.; Wood, B.L.; Marie, T.L.; Reinhardt, C.L.

    1980-10-01

    The results of a series of telephone interviews with groups of users of information on photovoltaics (PV) are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The report is 1 of 10 discussing study results. The overall study provides baseline data about information needs in the solar community. It covers these technological areas: photovoltaics, passive solar heating and cooling, active solar heating and cooling, biomass energy, solar thermal electric power, solar industrial and agricultural process heat, wind energy, ocean energy, and advanced energy storage. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from seven PV groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Researchers Working for Manufacturers, Representatives of Other Manufacturers, Representatives of Utilities, Electric Power Engineers, and Educators.

  4. [The DIAN study].

    PubMed

    Shimada, Hiroyuki

    2013-10-01

    The DIAN study compared the pathophysiological markers between carriers and non-carriers of mutation for autosomal dominant Alzheimer's disease (AD). They used the participant's age at baseline assessment and the parent's age at the onset of symptoms of AD to calculate the estimated delay in symptom onset. The study revealed that the biomarker change, which is the reduction of Aβ42 in the CSF of the carrier's brain, started approximately 15-20 years prior to the onset of symptoms. Subsequently, a chronological series of events took place: deposition of fibrillar Aβ as measured by positron emission tomography with the use of Pittsburgh compound B, increase in tau protein in the CSF, hippocampal atrophy and hypometabolism of FDG-PET, and cognitive and clinical changes. The researchers planned to start the prevention trial with 2 monoclonal antibodies and a BACE inhibitor. In contrast, the API study is the clinical trial of the anti-amyloid monoclonal antibody therapy associated with the early-onset familial AD (EOAD), which carries the PSEN1 E280A mutation. This study also showed changes in the same biomarker as reported in the DIAN study. Anti-amyloid treatment in asymptomatic AD (A4) is a prevention trial aimed at treating older individuals with normal cognition but at risk of developing AD dementia on the basis of having biomarker evidence of amyloid (preclinical AD). They selected solanezumab for the anti-amyloid treatment for A4. PMID:24101429

  5. Cosmos-1989 immunology studies

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, Gerald

    1991-01-01

    Evidence from both human and rodent studies has indicated that alterations in immunological parameters occur after space flight. The number of flight experiments has been small, and the full breadth of immunological alterations occurring after space flight remains to be established. Among the major effects on immune responses after space flight that have been reported are: alterations in lymphocyte blastogenesis and natural killer cell activity, alterations in production of cytokines, changes in leukocyte sub-population distribution, and decreases in the ability in the ability of bone marrow cells to respond to colony stimulating factors. Changes have been reported in immunological parameters of both humans and rodents. The significance of these alterations in relation to resistance to infection remains to be established. The current study involved a determination of the effects of flight on Cosmos mission 2044 on leukocyte subset distribution and the sensitivity of bone marrow cells to colony stimulating factor-GM. A parallel study with antiorthostatic suspension was also carried out. The study involved repetition and expansion of studies carried out on Cosmos 1887.

  6. Crystallization of the NADH-oxidizing domain of the Na{sup +}-translocating NADH:ubiquinone oxidoreductase from Vibrio cholerae

    SciTech Connect

    Tao, Minli; Türk, Karin; Diez, Joachim; Grütter, Markus G.; Fritz, Günter; Steuber, Julia

    2006-02-01

    The FAD domain of the NqrF subunit from the Na{sup +}-translocating NADH dehydrogenase from V. cholerae has been purified and crystallized. A complete data set was recorded at 3.1 Å. The Na{sup +}-translocating NADH:quinone oxidoreductase (Na{sup +}-NQR) from pathogenic and marine bacteria is a respiratory complex that couples the exergonic oxidation of NADH by quinone to the transport of Na{sup +} across the membrane. The NqrF subunit oxidizes NADH and transfers the electrons to other redox cofactors in the enzyme. The FAD-containing domain of NqrF has been expressed, purified and crystallized. The purified NqrF FAD domain exhibited high rates of NADH oxidation and contained stoichiometric amounts of the FAD cofactor. Initial crystallization of the flavin domain was achieved by the sitting-drop technique using a Cartesian MicroSys4000 robot. Optimization of the crystallization conditions yielded yellow hexagonal crystals with dimensions of 30 × 30 × 70 µm. The protein mainly crystallizes in long hexagonal needles with a diameter of up to 30 µm. Crystals diffract to 2.8 Å and belong to space group P622, with unit-cell parameters a = b = 145.3, c = 90.2 Å, α = β = 90, γ = 120°.

  7. Ventilation technologies scoping study

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2003-09-30

    This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the needs of California, determining residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and level of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  8. Seal design alternatives study

    SciTech Connect

    Van Sambeek, L.L.

    1993-06-01

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information.

  9. REP Concept Feasibility Study

    NASA Technical Reports Server (NTRS)

    Edwards, Daryl A.; Ensworth, Clinton B. F.; Goodnight, Thomas W.; Sheehe, Charles J.; Wiersma, Stephen C.; Adamsen, Paul B., II; Frank, Larry

    2004-01-01

    Radioisotope Electric Propulsion (REP) may have the potential to provide certain advantages, over conventional chemical propulsion, for outer planetary exploration involving small bodies and long term investigations for medium class missions requiring power comparable to past outer planetary exploration missions. This paper describes a study that investigates the concept s feasibility by performing a preliminary conceptual design of an REP-based spacecraft for a design reference mission. The mission utilizes a spacecraft with a radioisotope power supply less than one kilowatt while operating for a minimum of 10-years. A key element of the REP spacecraft is to ensure sustained science return by orbiting or flying in formation with selected targets. Utilizing current and impending technological advances, this study finds that at a conceptual design level a small body REP orbiter/explorer appears to be feasible for the design reference mission selected for this study.

  10. Parylene C Aging Studies.

    SciTech Connect

    Achyuthan, Komandoor; Sawyer, Patricia Sue.; Mata, Guillermo Adrian; White II, Gregory Von; Bernstein, Robert

    2014-09-01

    Parylene C is used in a device because of its conformable deposition and other advantages. Techniques to study Parylene C aging were developed, and "lessons learned" that could be utilized for future studies are the result of this initial study. Differential Scanning Calorimetry yielded temperature ranges for Parylene C aging as well as post-deposition treatment. Post-deposition techniques are suggested to improve Parylene C performance. Sample preparation was critical to aging regimen. Short-term (%7E40 days) aging experiments with free standing and ceramic-supported Parylene C films highlighted "lessons learned" which stressed further investigations in order to refine sample preparation (film thickness, single sided uniform coating, machine versus laser cutting, annealing time, temperature) and testing issues ("necking") for robust accelerated aging of Parylene C.

  11. Optimal symmetric flight studies

    NASA Technical Reports Server (NTRS)

    Weston, A. R.; Menon, P. K. A.; Bilimoria, K. D.; Cliff, E. M.; Kelley, H. J.

    1985-01-01

    Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory.

  12. Cosmos: 1989 immunology studies

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, Gerald

    1991-01-01

    The effects of flight on Cosmos mission 2044 on leukocyte subset distribution and the sensitivity of bone marrow cells to colony stimulating factor-GM were determined. A parallel study with antiorthostatic suspension was also carried out. The study involved repetition and expansion of studies performed on Cosmos 1887. Spleen and bone marrow cells were obtained from flown, vivarium control, synchronous control, and suspended rats. The cells were stained with a series of monoclonal antibodies directed against rat leukocyte cell surface antigens. Control cells were stained with a monoclonal antibody directed against an irrelevant species or were unstained. Cells were then analyzed for fluorescence using a FACSCAN flow cytometer. Bone marrow cells were placed in culture with GM-CSF in McCoy's 5a medium and incubated for 5 days. Cultures were then evaluated for the number of colonies of 50 cells or greater.

  13. Critical Density Interaction Studies

    SciTech Connect

    Young, P; Baldis, H A; Cheung, P; Rozmus, W; Kruer, W; Wilks, S; Crowley, S; Mori, W; Hansen, C

    2001-02-14

    Experiments have been performed to study the propagation of intense laser pulses to high plasma densities. The issue of self-focusing and filamentation of the laser pulse as well as developing predictive capability of absorption processes and x-ray conversion efficiencies is important for numerous programs at the Laboratory, particularly Laser Program (Fast Ignitor and direct-drive ICF) and D&NT (radiography, high energy backlighters and laser cutting). Processes such as resonance absorption, profile modification, linear mode conversion, filamentation and stimulated Brillouin scattering can occur near the critical density and can have important effects on the coupling of laser light to solid targets. A combination of experiments have been used to study the propagation of laser light to high plasma densities and the interaction physics of intense laser pulses with solid targets. Nonparaxial fluid codes to study nonstationary behavior of filamentation and stimulated Brillouin scattering at high densities have also been developed as part of this project.

  14. LAWS hurricane studies

    NASA Technical Reports Server (NTRS)

    Molinari, John

    1995-01-01

    The Laser Atmospheric Wind Sounder (LAWS) has recently been deselected from the Earth Observing System (EOS). A broad range of orbital altitudes and laser power are being considered for future wind lidar missions. As a result, as was anticipated in the proposed work, it may be impossible to meaningfully study tropical cyclones with lidar wind data because data coverage (i.e., swath width) is insufficient. Research on this grant has focused on how to maximize the benefits of a wind lidar regardless of the choice of platform or laser. Our studies have shown that major unsolved problems in tropical meteorology relate to the structure, dynamics, and role in tropical cyclogenesis of 'easterly waves'. These disturbances exist almost everywhere in the global subtropics. Results are described that focus upon easterly wave impacts on eastern Pacific tropical cyclogenesis. The availability of wind lidar data would create tremendous opportunities for the study of these waves and their role in the general circulation.

  15. Iron studies in hemophilia

    SciTech Connect

    Lottenberg, R.; Kitchens, C.S.; Roessler, G.S.; Noyes, W.D.

    1981-12-01

    Although iron deficiency is not recognized as a usual complication of hemophilia, we questioned whether intermittent occult loss of blood in urine or stool might predispose hemophiliacs to chronic iron deficiency. Seven men with factor VII and one with factor IX deficiency were studied. Blood studied, bone marrow aspirates, urine and stool samples, and ferrokinetics with total-body counting up to five months were examined. These data showed no excessive loss of blood during the study period; however, marrow iron stores were decidedly decreased, being absent in four subjects. We suggest that in some hemophiliacs, iron deposits in tissues such as synovial membranes may form a high proportion of the body's total iron stores.

  16. DWPF welder parametric study

    SciTech Connect

    Eberhard, B.J.; Harbour, J.R.; Plodinec, M.J.

    1994-06-01

    As part of the DWPF Startup Test Program, a parametric study has been performed to determine a range of welder operating parameters which will produce acceptable final welds for canistered waste forms. The parametric window of acceptable welds defined by this study is 90,000 {plus_minus} 15,000 lb of force, 248,000 {plus_minus} 22,000 amps of current, and 95 {plus_minus} 15 cycles (@ 60 cops) for the time of application of the current.

  17. Fireset materials aging study

    SciTech Connect

    Smith, H.M.; Arnold, C.; Bailey, M.E.

    1982-07-01

    A thermally-accelerated aging study of 10 selected organic materials used in a fireset has been conducted. The study included both quantitative and qualitative gas analyses as well as the measurement of physical properties before and after accelerated aging. The test plan involved single material aging, as well as pairs and larger groups to look for synergistic interactions. The material types tested were epoxies, polyurethanes, polysulfides, silicones, phenolics, polyolefins, and diallyl phthalates. Only two of the materials tested showed evidence of degradation as a result of aging.

  18. Radionuclide studies in impotence

    SciTech Connect

    Hilson, A.J.; Lewis, C.A. )

    1991-04-01

    Impotence may be of physiological origin with causes including vascular or neurological pathology. Alternatively, it may be of psychogenic origin. Clinicians can distinguish between psychological and organic impotence by observing nocturnal penile tumescence. Non-radionuclide investigations for organic impotence include penile plethysmography or pulse Doppler analysis for arterial supply, cavernosometry for venous drainage, and biothesiometry or evoked potentials for neurological pathology. Radionuclide studies are primarily based on the use of technetium 99m-pertechnetate, 99mTc-red blood cells, or xenon 133 to study the blood flow, with or without pharmacological intervention, commonly papaverine. 26 references.

  19. Studies in occultation astronomy

    NASA Technical Reports Server (NTRS)

    Veverka, J.

    1980-01-01

    Major scientific results are summarized for the following studies: (1) observations of the 8 April 1976 occultation of epsilon Geminorum by Mars; (2) studies in occultation techniques; and (3) the March 1974 occultation of Saturn by the Moon. A re-analysis of the 1974 lunar occultation of the Titan indicates that Titan is strongly limb darkened, with D approximately greater than 5800km; there is internal evidence in the data that Titan's atmosphere is inhomogeneous; and that observations are inconsistent with any sample homogeneous model atmosphere which matches the P (lambda) and Beta (lambda) observations of Titan.

  20. Mycology studies in space.

    PubMed

    Volz, P A

    1990-02-01

    The postflight phase of the Apollo MEED mycology attempts to identify survival according to exposure to specific quantitative space flight factors, while the second phase of studies identifies qualitative change other than cell survival [57]. Initial changes incurred in space on a fungal cell can be monitored and further examined on return of the fungal species test system to Earth. The postflight studies present a better understanding of the space environmental influences on living cells and a more clear understanding of the fungal species under examination. PMID:2325748

  1. Advanced engine study program

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Galler, D. E.; Denman, T. F.; Shied, R. A.; Black, J. R.; Fierstein, A. R.; Clark, G. L.; Branstrom, B. R.

    1993-01-01

    A design and analysis study was conducted to provide advanced engine descriptions and parametric data for space transfer vehicles. The study was based on an advanced oxygen/hydrogen engine in the 7,500 to 50,000 lbf thrust range. Emphasis was placed on defining requirements for high-performance engines capable of achieving reliable and versatile operation in a space environment. Four variations on the expander cycle were compared, and the advantages and disadvantages of each were assessed. Parametric weight, envelope, and performance data were generated over a range of 7,500 to 50,000 lb thrust and a wide range of chamber pressure and nozzle expansion ratio.

  2. Hybrid receiver study

    NASA Technical Reports Server (NTRS)

    Stone, M. S.; Mcadam, P. L.; Saunders, O. W.

    1977-01-01

    The results are presented of a 4 month study to design a hybrid analog/digital receiver for outer planet mission probe communication links. The scope of this study includes functional design of the receiver; comparisons between analog and digital processing; hardware tradeoffs for key components including frequency generators, A/D converters, and digital processors; development and simulation of the processing algorithms for acquisition, tracking, and demodulation; and detailed design of the receiver in order to determine its size, weight, power, reliability, and radiation hardness. In addition, an evaluation was made of the receiver's capabilities to perform accurate measurement of signal strength and frequency for radio science missions.

  3. Amtrak fuel consumption study

    SciTech Connect

    Hitz, J.

    1981-02-01

    This report documents a study of fuel consumption on National Railroad Passenger Corporation (Amtrak) trains and is part of an effort to determine effective ways of conserving fuel on the Amtrak system. The study was performed by the Transportation Systems Center (TSC). A series of 26 test runs were conducted on Amtrak trains operating between Boston, Massachusetts, and New Haven, Connecticut, to measure fuel consumption, trip time and other fuel-use-related parameters. The test data were analyzed and compared with results of the TSC Train Performance Simulator replicating the same operations.

  4. Studies in neuroendocrine pharmacology

    NASA Technical Reports Server (NTRS)

    Maickel, R. P.

    1976-01-01

    The expertise and facilities available within the Medical Sciences Program section on Pharmacology were used along with informational input from various NASA sources to study areas relevant to the manned space effort. Topics discussed include effects of drugs on deprivation-induced fluid consumption, brain biogenic amines, biochemical responses to stressful stimuli, biochemical and behavioral pharmacology of amphetamines, biochemical and pharmacological studies of analogues to biologically active indole compounds, chemical pharmacology: drug metabolism and disposition, toxicology, and chemical methodology. Appendices include a bibliography, and papers submitted for publication or already published.

  5. Reporting of teratology studies.

    PubMed

    Barrow, Paul C; Reynaud, Lucie

    2013-01-01

    The regulatory toxicology report is an unusual document that requires a particular skill to write. The report must be clear, accurate, concise, and focused. A clear and direct writing style is required. The end-users of the report will hope to find the information they seek with as little effort as possible. Few, or none, will read the entire document. The author should aim to appease the user by obliging him to read as little text and turn as few pages as possible. This chapter gives tips and guidance on how to present the experimental data and write the narrative text in the final study report for a teratology study. PMID:23138913

  6. Outer planet studies

    NASA Technical Reports Server (NTRS)

    Lutz, Barry L.

    1991-01-01

    The focus is on observational studies of the composition, structure, and variability of planetary, satellite, and cometary atmospheres. The techniques used include spectroscopy, spectrophotometry, and photometric imaging in the spectral region from 3000 A to 5 microns. In addition to carrying out basic research into the origin, evolution, and current state of the solar system, these studies provide ground-truth support for observations of the solar system by NASA's missions, including the Voyager and Galileo Spacecraft, the Hubble Space Telescope, and the proposed Comet Rendezvous Asteroid Flyby (CRAF)-Cassini Mission.

  7. DWPF Welder Parametric Study

    SciTech Connect

    Plodinec, M.J.

    1998-11-20

    After being filled with glass, DWPF canistered waste forms will be welded closed using an upset resistance welding process. This final closure weld must be leaktight, and must remain so during extended storage at SRS. As part of the DWPF Startup Test Program, a parametric study (DWPF-WP-24) has been performed to determine a range of welder operating parameters which will produce acceptable welds. The parametric window of acceptable welds defined by this study is 90,000 + 15,000 lb of force, 248,000 + 22,000 amps of current, and 95 + 15 cycles* for the time of application of the current.

  8. Morphing Terminology Study

    SciTech Connect

    Rose, Stuart J.; Brockman, Fred J.; Hart, Michelle L.; Engel, David W.; Valentine, Nancy B.; Calapristi, Augustin J.

    2010-06-28

    This study investigates methods of automatically identifying and characterizing significant transitions in term usage over time. Within scientific literature, the occurrence of terms reflects the use of technologies and techniques as well as the study of specific species and materials. Transitions in terminology usage may be a result of vocabulary standardization or specialization in which terms are replaced with their shorter form. They may also be a result of new applications, combinations, alternatives, or interests that result in the appearance of new or existing terminology in unexpected contexts.

  9. Fathead fecundity study

    SciTech Connect

    Barman, M.A.E.; Geis, S.; Repavich, W.; Schappe, K.

    1995-12-31

    Fathead minnows (Pimephales promelas) are cultured in controlled laboratory settings for use in aquatic toxicity testing. Culturing is done to maintain a continuous supply of organisms of all ages; breeders, juveniles and larvae. This study is designed to determine the age at which peak egg production occurs. Fish are paired, one male to one female, at three to four months of age. Daily egg production is recorded and graphed. The graph of egg production vs. fish age will determine the age at which peak egg production occurs. The results of this study will provide information for more efficient use of lab space and staff, while maximizing egg production.

  10. National Facilities study

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This study provides a set of recommendations for improving the effectiveness of our nation's aeronautics and space facilities. The study plan considers current and future government and commercial needs as well as DOD and NASA mission requirements through the year 2023. It addresses shortfalls in existing capabilities, new facility requirements, upgrades, consolidations, and phase-out of existing facilities. If the recommendations are implemented, they will provide world-class capability where it is vital to our country's needs and make us more efficient in meeting future needs.

  11. Fluorescence study of sugars

    NASA Astrophysics Data System (ADS)

    Thongjamroon, Sunida; Pattanaporkratana, Apichart

    2015-07-01

    We studied photoemission of monosaccharides and disaccharides using laser-induced fluorescence spectroscopy. A 532- nm, 10 mW, laser was used to excite the samples and back-scattering signals were collected by a spectrometer. We found that most sugars show weak fluorescence in solid phase but do not fluoresce when dissolved in water solutions. The emission spectra show similar peak intensity at 590 nm, but they are different in emission intensities. We suggest that the fluorescence spectra may be used to differentiate sugar type, even though the origin of the fluorescence is unclear and needed further study.

  12. Cryogenic Propellant Densification Study

    NASA Technical Reports Server (NTRS)

    Ewart, R. O.; Dergance, R. H.

    1978-01-01

    Ground and vehicle system requirements are evaluated for the use of densified cryogenic propellants in advanced space transportation systems. Propellants studied were slush and triple point liquid hydrogen, triple point liquid oxygen, and slush and triple point liquid methane. Areas of study included propellant production, storage, transfer, vehicle loading and system requirements definition. A savings of approximately 8.2 x 100,000 Kg can be achieved in single stage to orbit gross liftoff weight for a payload of 29,484 Kg by utilizing densified cryogens in place of normal boiling point propellants.

  13. Studies in Empowerment.

    ERIC Educational Resources Information Center

    Van Galen, Jane, Ed.; And Others

    1992-01-01

    This theme issue of the serial "Educational Foundations" contains five articles devoted to the topic of "Studies in Empowerment." In "The Disempowering of Empowerment: Out of the Revolution and into the Classroom," Margaret D. LeCompte and Kathleen Bennett deMarrais focused on placing the term in proper historical context. Guy B. Senese "Away from…

  14. Shuttle Communications Blackout Study

    NASA Technical Reports Server (NTRS)

    Haben, R. L.; Budica, R. J.

    1983-01-01

    Space Shuttle Orbiter Entry Communications Blackout Study computer program models, investigates, and predicts communication blackout envelopes based on mission entry trajectory and associated data from tracking stations. Of interest to those designing and using communications systems susceptible to blackout. Program is readily adapted to predict entry communications blackout for any nonablative entry vehicle.

  15. Humanizing Home Study.

    ERIC Educational Resources Information Center

    Hass, Glen; Fleury, Donna

    The use of correspondence or home study courses for noncredit is a recent development in the field of adult education. The challenge facing the extension worker is to be able to develop and deliver the type of program that not only meets the learning (content) need of the participant but that also meets the learning situation. Unfortunately, the…

  16. Object motion analysis study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The use of optical data processing (ODP) techniques for motion analysis in two-dimensional imagery was studied. The basic feasibility of this approach was demonstrated, but inconsistent performance of the photoplastic used for recording spatial filters prevented totally automatic operation. Promising solutions to the problems encountered are discussed, and it is concluded that ODP techniques could be quite useful for motion analysis.

  17. Female Studies: No. 1.

    ERIC Educational Resources Information Center

    Tobias, Sheila

    This document presents an anthology of syllabi of courses taught or proposed during 1969-70 in the field of Womens Studies. The courses originated in a variety of manners. In some colleges, students pressed for courses based on the insights and challenges of women's liberation material. In other institutions, faculty offered interdisciplinary…

  18. Teaching Biblical Studies Online

    ERIC Educational Resources Information Center

    Delamarter, Stephen; Gravett, Sandra L.; Ulrich, Daniel W.; Nysse, Richard W.; Polaski, Sandra Hack

    2011-01-01

    In this edited transcript of a panel at the Society of Biblical Literature (November 23, 2009, Boston, Massachusetts), five Bible scholars give brief presentations on various challenges and opportunities encountered when teaching academic biblical studies courses online in both undergraduate and theological education contexts. Each presentation is…

  19. Ethics and Study Abroad

    ERIC Educational Resources Information Center

    Hoffa, William W.

    2007-01-01

    It came as a great surprise recently to read in "The New York Times" that the New York attorney general's office had launched an investigation into possible financial improprieties between colleges and outside organizations that provide study-abroad programs. Subpoenas had been issued to five of the largest program providers, "with more to come."…

  20. INTRODUCTION AND STUDY DESIGN

    EPA Science Inventory

    Under the sponsorship of the UNEP/ILO/IPCS, 17 laboratories from diverse regions of the world participated in evaluating the utility of four plant bioassays for detecting genetic hazards of environmental chemicals. he bioassays included in this collaborative study were Arabidopsi...

  1. Eastern Frequency Response Study

    SciTech Connect

    Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  2. An Ethnic Studies Evolution

    ERIC Educational Resources Information Center

    Boulard, Garry

    2006-01-01

    As a student in the Chicana/o studies program at the University of Texas at El Paso (UTEP), Jesse S. Arrieta decided that her classroom instruction about the culture and history of people of Mexican origin wasn't enough. Arrieta, 27, who graduated from UTEP in 2002 before earning a master's in American history from the University of California,…

  3. Screen Study Guides.

    ERIC Educational Resources Information Center

    Duncan, Barry

    1969-01-01

    This study guide for Arthur Lipsett's film "Very Nice, Very Nice" is in four parts. First, it describes and evaluates the film, discusses Lipsett's unusual juxtapositions, fast cutting, and fragmented speeches as indications of his satirical intent, and suggests that the only meaningful summation of the film's content is through pattern…

  4. Cholera studies*†

    PubMed Central

    Pollitzer, R.

    1955-01-01

    The morphological characteristics, biochemical properties, and cultural characteristics of V. cholerae are described in great detail in this study. The author also discusses the resistance of the organism to temperature, humidity, sunlight, and various chemicals, as well as the viability of V. cholerae outside the body (in faeces, contaminated material, food, beverages, water, etc.). PMID:14379012

  5. Studies in zirconium oxidation

    NASA Technical Reports Server (NTRS)

    Draley, J. E.; Drunen, C. J.; Levitan, J.

    1968-01-01

    Study provides insight into the oxidation mechanism of zirconium by combining electrical measurements with oxidation data. The measurement of electrical potential across growing scale on zirconium and the determination of conventional weight-change oxidation data were carried out at 550, 700, and 800 degrees C.

  6. Turbine blade damping study

    NASA Technical Reports Server (NTRS)

    Dominic, R. J.

    1984-01-01

    Research results and progress on the performance of bladed systems is reported the different topics discussed include: the study of turbine blade damping; forced vibrations of friction damped beam moistures in two dimensions; and a users manual for a computer program for dynamic analysis of bladed systems.

  7. NGLW RCRA Storage Study

    SciTech Connect

    R. J. Waters; R. Ochoa; K. D. Fritz; D. W. Craig

    2000-06-01

    The Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Engineering and Environmental Laboratory contains radioactive liquid waste in underground storage tanks at the INTEC Tank Farm Facility (TFF). INTEC is currently treating the waste by evaporation to reduce the liquid volume for continued storage, and by calcination to reduce and convert the liquid to a dry waste form for long-term storage in calcine bins. Both treatment methods and activities in support of those treatment operations result in Newly Generated Liquid Waste (NGLW) being sent to TFF. The storage tanks in the TFF are underground, contained in concrete vaults with instrumentation, piping, transfer jets, and managed sumps in case of any liquid accumulation in the vault. The configuration of these tanks is such that Resource Conservation and Recovery Act (RCRA) regulations apply. The TFF tanks were assessed several years ago with respect to the RCRA regulations and they were found to be deficient. This study considers the configuration of the current tanks and the RCRA deficiencies identified for each. The study identifies four potential methods and proposes a means of correcting the deficiencies. The cost estimates included in the study account for construction cost; construction methods to minimize work exposure to chemical hazards, radioactive contamination, and ionizing radiation hazards; project logistics; and project schedule. The study also estimates the tank volumes benefit associated with each corrective action to support TFF liquid waste management planning.

  8. Pilot Training Study.

    ERIC Educational Resources Information Center

    Mooz, William E.

    The purpose of the Pilot Training Study is to produce tools with which to analyze the pilot training process of the Air Force in terms of the resources required to train pilots and the cost of pilot training. These tools allow examination of the training courses themselves, and also of the policy factors which drive the need for pilots. The tools…

  9. AGRICULTURAL HEALTH STUDY

    EPA Science Inventory

    The Agricultural Health Study is a large cohort of 90,000 licensed pesticide applicators, plus 30,000 spouses and 20,000 children who are exposed either directly or indirectly. Exposure to pesticides is widespread and is important beyond the agricultural community. Other exposure...

  10. FLARE EFFICIENCY STUDY

    EPA Science Inventory

    The report gives results of a full-scale experimental study to determine the efficiencies of flare burners for disposing of hydrocarbon (HC) emissions from refinery and petrochemical processes. With primary objectives of determining the combustion efficiency and HC destruction ef...

  11. Comet rendezvous mission study

    NASA Technical Reports Server (NTRS)

    Friedlander, A. L.; Wells, W. C.

    1971-01-01

    Four periodic comets with perihelia between 1980 and 1986 (Encke, d'Arrest, Kipff, and Halley) are used as candidates for the comet rendezvous mission study. All these comet apparitions are especially favorable for rendezvous missions, because of early earth-based comet recovery, good opportunities to view their activity from earth, and reasonable launch vehicle and trajectory requirements for nominal payloads.

  12. Geothermal Case Studies

    DOE Data Explorer

    Young, Katherine

    2014-09-30

    database.) In fiscal year 2015, NREL is working with universities to populate additional case studies on OpenEI. The goal is to provide a large enough dataset to start conducting analyses of exploration programs to identify correlations between successful exploration plans for areas with similar geologic occurrence models.

  13. Racer efficacy study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Racer (ammonium nonanoate) is a non-selective contact herbicide that controls several weed species. Racer has been labeled by EPA in the past year for weed control in food crops and is close to receiving approval for use by organic producers. The objective of this study was to verify results from ...

  14. Acid Rain Study Guide.

    ERIC Educational Resources Information Center

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  15. Study of coronagraphic techniques

    NASA Astrophysics Data System (ADS)

    Tolls, Volker; Aziz, Michael; Gonsalves, Robert A.; Korzennik, Sylvain; Labeyrie, Antoine; Lyon, Richard; Melnick, Gary; Schlitz, Ruth; Somerstein, Steve; Vasudevan, Gopal; Woodruff, Robert

    2006-06-01

    Smithsonian Astrophysical Observatory (SAO) has set up a program to study coronagraphic techniques. The program consists of the development of new fabrication methods of occulter masks, characterization of the manufactured masks, and application of the masks to study speckle reduction technique. Our occulter mask fabrication development utilizes a focused ion beam system to directly shape mask profiles from absorber material. Initial milling trials show that we can shape nearly Gaussian-shaped mask profiles. Part of this development is the characterization of absorber materials, poly(methyl methacrylate) doped with light-stable chromophores. For the characterization of the masks we have built a mask scanner enabling us to scan the transmission function of occulter masks. The real mask transmission profile is retrieved applying the maximum entropy method to deconvolve the mask transmission function from the beam profile of the test laser. Finally, our test bed for studying coronagraphic techniques is nearing completion. The optical setup is currently configured as a classical coronagraph and can easily be re-configured for studying speckle reduction techniques. The development of the test bed control software is under way. This paper we will give an update of the status of the individual program elements.

  16. Alternative School Administration Study

    ERIC Educational Resources Information Center

    Shellinger, Mark

    2005-01-01

    The purpose of this study was to determine how principals spend their time and to test a new structure using business management trained staff to increase principal time spent on academic achievement and gap closure. Twenty-one elementary school principals were randomly selected for a week-long time-task analysis. Data collectors shadowed the…

  17. Applied Music (Individual Study).

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin.

    Background information and resources to help students in grades 9-12 in Texas pursue an individual study contract in applied music is presented. To fulfill a contract students must publicly perform from memory, with accompaniment as specified, three selections from a list of approved music for their chosen field (instrument or voice). Material…

  18. Tailored Barium Swallow Study

    MedlinePlus

    ... a perfect study, but it is the best method to gather information about how you/your child swallows and the risk there may be for food or liquids going into the airway. The Speech Pathologist plans the TBS so that a sample of a few swallows of various textures shows ...

  19. Eye tissues study

    NASA Astrophysics Data System (ADS)

    Tuchin, Valery V.; Bashkatov, Alexey N.; Maksimova, Irina L.; Sinichkin, Yurii P.; Simonenko, Georgy V.; Genina, Elina A.; Lakodina, Nina A.

    2001-08-01

    Theoretical and in vitro and in vivo experimental study of spectral and polarization characteristics of the human and rabbit eye tissues are presented. The possibility of control of optical properties of eye cornea, lens and sclera is discussed and realized experimentally for glucose solution as the refractive index matching factor.

  20. Energy Manpower Study, 1980.

    ERIC Educational Resources Information Center

    Seward County Community Coll., Liberal, KS.

    A study was conducted in Kansas to determine the need for vocational education programs in solar energy technology in community colleges. After a literature search revealed a project need for trained solar energy technicians, Seward County Community College surveyed 100 Kansas heating, air conditioning, and plumbing companies to determine future…

  1. Case Studies in Biology.

    ERIC Educational Resources Information Center

    Zeakes, Samuel J.

    1989-01-01

    A case study writing exercise used in a course on parasitology was found to be a powerful learning experience for students because it involved discipline-based technical writing and terminology, brought the students in as evaluators, applied current learning, caused interaction among all students, and simulated real professional activities. (MSE)

  2. Social Studies Journal, 2003.

    ERIC Educational Resources Information Center

    West, Leo R., Ed.

    2003-01-01

    This theme issue of the "Social Studies Journal" focuses on the worldwide conflict known in the United States as the French and Indian War (1754-1763). The volume is dedicated to examining the conflict in Pennsylvania. Western Pennsylvania became a battle-scarred landscape as the British and French, with their Native American allies, struggled for…

  3. Summer Study Abroad.

    ERIC Educational Resources Information Center

    Cohen, Gail A., Ed.

    This catalog describes summer study abroad programs around the world for students of college age and up. The included information was obtained from surveys conducted by the Institute of International Education in September 1978. The catalog contains programs of interest to the pre-college student who wants to improve his language skills before…

  4. World Studies: Selected Organizations.

    ERIC Educational Resources Information Center

    Social Studies Development Center, Bloomington, IN.

    Descriptive information is given for 80 organizations. The organizations are concerned with world studies ranging from global population concerns to specific cultural societies. They represent global issues concerning education and teaching, international education, population and food, war and peace, religion, economics, and ocean education.…

  5. Vacation Study Abroad.

    ERIC Educational Resources Information Center

    Howard, Edrice Marguerite, Ed.

    This directory of vacation study-abroad programs provides brief descriptions of the programs offered by institutions around the world. An introductory section describes the organization of the listings (which provide program sponsor and name, location, dates, subjects, credit, eligibility, instruction, highlights, costs, housing, deadline, and…

  6. The smallest study club.

    PubMed

    Sauget, Earl

    2002-01-01

    A specialist on Guam describes a study club of specialists on the island. Although the number of participants is small in absolute terms, the group's monthly meetings centered around cases serves the functions of stimulating currency and self learning and enhances coordination of complex treatment cases. PMID:12602217

  7. Study Leave in Sweden.

    ERIC Educational Resources Information Center

    Gould, Arthur

    2003-01-01

    Analysis of statistics since 1994 on the use of study leave as allowed by a 1974 Swedish law indicates that about 1% of the work force takes leave at any time. Women and manual workers benefit more than men and salaried workers. Leave application causes employees few problems with employers but financial assistance is a concern. (Contains 37…

  8. NACUBO Endowment Study, 1998.

    ERIC Educational Resources Information Center

    Cambridge Associates, Inc., Boston, MA.

    This report presents the results of a 1998 study of endowment assets of 509 higher education institutions, and is intended to allow administrators and trustees to evaluate the performance of their endowments and to acquaint them with the investment policies and practices of other higher education institutions. A brief abstract notes some…

  9. Rx for Social Studies.

    ERIC Educational Resources Information Center

    Wheeler, Ron

    1996-01-01

    Maintains that the explosion of information and teaching resources (multimedia, audio-visual, computer networks) represents a mixed blessing. Argues that the proliferation of information access necessitates students learning critical and evaluative skills. Discusses the implications of this for social studies instruction. (MJP)

  10. General Aviation Manpower Study.

    ERIC Educational Resources Information Center

    Feller, Richard

    1982-01-01

    Highlights a study examining manpower supply/demand in general aviation. Eight job categories were examined: pilots, flight instructors, engineers, machinists/toolers, and A&P, airframe, and avionics technicians. Findings among others indicate that shortages in indicated job categories exist because personnel are recruited by other industries. (JN)

  11. Child Study Manual.

    ERIC Educational Resources Information Center

    Polk County Public Schools, Bartow, FL.

    This manual from the Polk County Public Schools in Bartow, Florida, was developed for school personnel and parents to aid in their efforts to develop successful behavioral and academic interventions to enhance the educational outcomes for students. Section 1 describes the child study team which is comprised of an administrator, guidance counselor,…

  12. African Studies Computer Resources.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

    African studies computer resources that are readily available in the United States with linkages to Africa are described, highlighting those most directly corresponding to African content. Africanists can use the following four fundamental computer systems: (1) Internet/Bitnet; (2) Fidonet; (3) Usenet; and (4) dial-up bulletin board services. The…

  13. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    The use is studied of tether systems to improve the lowest possible steady gravity level on the Space Station. Particular emphasis is placed by the microgravity community on the achievement of high quality microgravity conditions. The tether capability is explored for active control of the center of gravity and the analysis of possible tethered configurations.

  14. [Prehistoric population studies].

    PubMed

    Posse, Z C

    1985-01-01

    Studies concerning prehistoric populations in the Americas are discussed. "A review is made of research conducted in America focusing...on indigenous populations prior to contacts with Europeans, and those which, employing archaeological and historical sources, seek to evaluate the population and establish depopulation indexes for the said societies." (SUMMARY IN ENG) PMID:12341861

  15. HOUSTON AEROSOL CHARACTERIZATION STUDY

    EPA Science Inventory

    An intensive field study of ambient aerosols was conducted in Houston between September 14 and October 14, 1978. Measurements at 12 sites were made using (1) two relocatable monitoring systems instrumented for aerosol and gaseous pollutants, (2) a network of high volume samplers ...

  16. Asian American Studies.

    ERIC Educational Resources Information Center

    Liu, William T.; Yu, Elena S. H.

    The sociodemographic and socioeconomic characteristics of all Asian American communities since 1950 have been greatly influenced by federal immigration legislation, and it is not possible to consider the field of Asian American studies without an understanding of the history of immigration legislation. Asian American research may be divided into…

  17. EUDISED: Technical Studies, 1971.

    ERIC Educational Resources Information Center

    Council of Europe, Strasbourg (France). Documentation Center for Education in Europe.

    This collection of technical studies concerning the European Documentation and Information System for Education (EUDISED) presents the problems of educational information, documentation, and dissemination in Europe. In the first report, transmitter-receiver relationships and the understanding of each other's roles and needs are discussed. The…

  18. Access to space study

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report summarizes the results of a comprehensive NASA in-house study to identify and assess alternate approaches to access to space through the year 2030, and to select and recommend a preferred cause of action. The goals of the study were to identify the best vehicles and transportation architectures to make major reductions in the cost of space transportation (at least 50%), while at the same time increasing safety for flight crews by at least an order of magnitude. In addition, vehicle reliability was to exceed 0.98 percent, and, as important, the robustness, pad time, turnaround time, and other aspects of operability were to be vastly improved. This study examined three major optional architectures: (1) retain and upgrade the Space Shuttle and expendable launch vehicles; (2) develop new expendable vehicles using conventional technologies and transition from current vehicles beginning in 2005; and (3) develop new reusable vehicles using advanced technology, and transition from current vehicles beginning in 2008. The launch-needs, mission model utilized for for the study was based upon today's projection of civil, defense, and commercial mission payload requirements.

  19. WELL PURGING STUDY

    EPA Science Inventory

    Purging of wells with bailers has been a standard practice in the underground storage tank program as well as other groundwater regulatory programs for many years. Several studies in the Northeast and the West have shown that, under certain circumstances, samples collected witho...

  20. PHILADELPHIA ROADWAY STUDY

    EPA Science Inventory

    The Philadelphia Roadway Study was conducted to determine the horizontal and vertical extinction profiles of particles generated by vehicles, including fine (0-2.5 micrometers), coarse (2.5-15 micrometers), and total (0-15 micrometers) size fractions in the area surrounding a maj...

  1. Pangnirtung: A Community Study.

    ERIC Educational Resources Information Center

    Benyk, Pearl, Ed.

    This booklet provides reference materials for teachers of social studies in the Northwest Territories (Canada). The information was gathered during workshops attended by elders, community representatives, and teachers from the region. A geography section describes the location of Pangnirtung on Baffin Island and the geology, climate, vegetation,…

  2. DETROIT CHILDREN'S HEALTH STUDY

    EPA Science Inventory

    The Detroit Children's Health Study will consist of health questionnaires for 15,000 children enrolled in the fourth- and fifth-grades of selected elementary schools, and measurements of lung function and exhaled breath in a subset of 3,500 of these children. Participation in bo...

  3. 12 Batch coalescing studies

    SciTech Connect

    Kourbanis, I.; Wildman, D.; /Fermilab

    1995-01-01

    The purpose of the study was to identify and correct the problems in the 12 batch coalescing. The final goal is to be able to coalesce 12 booster batches of 11 bunches each into 12 bunches spaced at 21 buckets apart with an average intensity of 200 E9 ppb.

  4. Urban Expansion Study

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Under an Egyptian government contract, PADCO studies urban growth in the Nile Area. They were assisted by LANDSAT survey maps and measurements provided by TAC. TAC had classified the raw LANDSAT data and processed it into various categories to detail urban expansion. PADCO crews spot checked the results, and correlations were established.

  5. Reinventing Social Studies

    ERIC Educational Resources Information Center

    St. Jarre, Kevin

    2008-01-01

    There is so much more to preparing a citizen than merely running students like lemmings through a three-year succession of history survey courses. Everyone is neglecting most of the social sciences in American high schools today, favoring the sequential and systematic delivery of history. What should be primary in the teaching of social studies,…

  6. MONTEFIORE - ASTHMA INTERVENTION STUDY

    EPA Science Inventory

    Montefiore Medical Center is conducting an asthma intervention study using, in part, their Lead Safe House on the Montefiore campus, a low-allergen controlled setting. There are three groups of participants, all severe asthmatics. The first group is being moved temporarily into...

  7. Studying Ancient History.

    ERIC Educational Resources Information Center

    Barrow, Robin

    1982-01-01

    Defends the value and relevance of the study of ancient history and classics in history curricula. The unique homogeneity of the classical period contributes to its instructional manageability. A year-long, secondary-level course on fifth-century Greece and Rome is described to illustrate effective approaches to teaching ancient history. (AM)

  8. Social Studies: Grade 8.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education, Winnipeg.

    This Manitoba (Canada) curriculum guide for eighth grade social studies students contains suggested teaching strategies and learning activities in four units covering: (1) life during prehistoric and early historic times; (2) ancient civilizations; (3) life in early modern Europe; and (4) life in the modern world. Each unit includes an overview,…

  9. Repository seals requirements study

    SciTech Connect

    1997-11-03

    The Yucca Mountain Site Characterization Project, managed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) is conducting investigations to support the Viability Assessment and the License Application for a high-level nuclear waste repository at Yucca Mountain, Nevada. The sealing subsystem is part of the Yucca Mountain Waste Isolation System. The Yucca Mountain Site Characterization Project is currently evaluating the role of the sealing subsystem (shaft, ramp and exploratory borehole seals) in achieving the overall performance objectives for the Waste Isolation System. This report documents the results of those evaluations. This report presents the results of a repository sealing requirements study. Sealing is defined as the permanent closure of the shafts, ramps, and exploratory boreholes. Sealing includes those components that would reduce potential inflows above the repository, or that would divert flow near the repository horizon to allow vertical infiltration to below the repository. Sealing of such features as emplacement drifts was not done in this study because the current capability to calculate fracture flow into the drifts is not sufficiently mature. The objective of the study is to provide water or air flow performance based requirements for shafts, ramps, and exploratory boreholes located near the repository. Recommendations, as appropriate, are provided for developing plans, seals component testing, and other studies relating to sealing.

  10. Parts application handbook study

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The requirements for a NASA application handbook for standard electronic parts are determined and defined. This study concentrated on identifying in detail the type of information that designers and parts engineers need and expect in a parts application handbook for the effective application of standard parts on NASA projects.

  11. Vocational Teacher Education Study.

    ERIC Educational Resources Information Center

    Tulloch, Charlotte

    A study was conducted to determine the present state of vocational education in Kentucky and the supply of and demand for vocational teachers. Results are summarized for vocational teacher education in general and for teachers in the areas of agricultural education, business and office education, marketing and distributive education, health and…

  12. Case Studies Behavior Modification.

    ERIC Educational Resources Information Center

    Wark, David M.

    The case histories of five students enrolled in a university course in how to study are reported. The students ranged in age from 18 to 35, included two males and three females, and varied in school experience from no college in one case and some college in two cases to college degrees in two cases. Students were initially taught to chart their…

  13. Collaboration through Study Circles

    ERIC Educational Resources Information Center

    McCoy, Martha L.

    2005-01-01

    Communities are telling inspiring stories about what happens when they use public dialogue and action to involve large numbers of citizens--with the greatest diversity possible--in a search for common ground to resolve tough issues like race, community police relations, and education reform. These efforts, often called "study circles," are…

  14. IMMUNOASSAY HUMAN EXPOSURE STUDIES

    EPA Science Inventory

    The Human Exposure Research Branch has developed several enzyme-linked immunosorbent assay (ELISA) methods to support human exposure assessment studies. Immunoassays to detect low levels (<10 ng/mL) of chlorpyrifos in food, track-in dirt and house dust have been applied to sam...

  15. TRAHC Folklife Study Guides.

    ERIC Educational Resources Information Center

    Texarkana Regional Arts and Humanities Council, Inc., TX.

    Each of the seven study guides combined in this packet provides a lesson that includes a reading or descriptive narrative of the topic, along with teaching objectives, questions to consider, and suggested classroom activities. Topics covered are: (1) "Introduction to the Concept of Folklife"; (2) "Southern Gospel Music and Song"; (3) "No Brag,…

  16. Studies in Southwest Spanish.

    ERIC Educational Resources Information Center

    Bowen, J. Donald, Ed.; Ornstein, Jacob, Ed.

    The Spanish dialects of the Southwest United States have received little serious attention until recently. The present volume contains studies designed to contribute to the understanding and acceptance of Southwest Spanish. The book consists of the following chapters: (1) "Linguistic Diversity in Southwest Spanish," by Garland D. Bills and Jacob…

  17. SOLID WASTE STUDY

    SciTech Connect

    PAUL G. ORTIZ - COLEMAN RESEARCH CORP /COMPA INDUSTRIES

    1995-08-01

    The purpose of this document is to study the solid waste issues brought about by a Type C Investigation; ``Disposal of Inappropriate Material in the Los Alamos County Landfill'' (May 28, 1993). The study was completed in August 1995 by Coleman Research Corporation, under subcontract number 405810005-Y for Los Alamos National Laboratory (LANL). The study confirmed the issues identified in the Type C investigation, and also ascertained further issues or problems. During the course of this study two incidents involving hazardous waste resulted in the inappropriate disposal of the waste. An accidental spill, on June 8, 1995, at one of Laboratory buildings was not handled correctly, and ended up in the LAC Landfill. Hazardous waste was disposed of in a solid waste container and sent to the Los Alamos County Landfill. An attempt to locate the hazardous waste at the LAC Landfill was not successful. The second incident involving hazardous waste was discovered by the FSS-8, during a random dumpster surveillance. An interim dumpster program managed by FSS-8 discovered hazardous waste and copper chips in the solid waste, on August 9, 1995. The hazardous waste and copper chips would have been transported to the LAC Landfill if the audit team had not brought the problem to the awareness of the facility waste management personnel.

  18. Cholera studies*†

    PubMed Central

    Pollitzer, R.; Burrows, W.

    1955-01-01

    Relevant information regarding the numerous problems encountered in cholera immunity is dealt with in great detail in this study. Toxin production, bacterial virulence, serological reactions, and the antigenic structure of V. cholerae are discussed. Natural, passive, and active cholera immunity receives special attention, the authors describing the various means of vaccination as well as the evaluation of the immunity induced. PMID:13240451

  19. LUXEMBOURG INCOME STUDY (LIS)

    EPA Science Inventory

    The LIS database is a collection of household income surveys. The LIS project began in 1983 under the joint sponsorship of the government of the Grand Duchy of Luxembourg and the Center for Population, Poverty and Policy Studies (CEPS). The project is mainly funded by the nationa...

  20. Everglades Environmental Study Units.

    ERIC Educational Resources Information Center

    Florida State Dept. of Education, Tallahassee. Office of Environment Education.

    These environmental study units consist of four modules and a tape-slide presentation on the Everglades National Park. Although not required for completion of the modules, the slide-tape presentation provides a resource for orientation of teachers and parents to camping experience for school children in an environmental education program. The four…

  1. Unwelcome in Women's Studies

    ERIC Educational Resources Information Center

    Kamolnick, Paul

    2007-01-01

    In this article, the author presents a case of a professor who, in electing to teach a special-topics course on human sex differences, discovers an entire program in the College of Arts and Sciences--Women's Studies (WMST)--whose criteria for course inclusion are in direct violation of several major rules and regulations governing academics at…

  2. SERT C project study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The SERT C (Space Electric Rocket Test - C) project study defines a spacecraft mission that would demonstrate the technology readiness of ion thruster systems for primary propulsion and station keeping applications. As a low cost precursor, SERT C develops the components and systems required for subsequent Solar Electric Propulsion (SEP) applications. The SERT C mission requirements and preliminary spacecraft and subsystem design are described.

  3. Cholera studies*†

    PubMed Central

    Pollitzer, R.

    1954-01-01

    In this, the first of a series of cholera studies, the history of the disease from its earliest recorded appearance up to 1923 is outlined, and its geographical distribution described. The origins and main routes of spread of the six great pandemics are indicated; possible causes of the variations in mortality which accompanied them are discussed. PMID:13160764

  4. Teaching Social Studies Indepth

    ERIC Educational Resources Information Center

    Ediger, Marlow

    2014-01-01

    Social studies, too frequently, is taught in a survey approach whereby pupils obtain subject matter in a shallow manner. Forgetting and hazy recalls are typical of this procedure of instruction. Covering many topics in a relatively short period of time does not make for achievement which is long-lasting. Then too, selected pupils might be left…

  5. Area Studies: China.

    ERIC Educational Resources Information Center

    Blouin, Virginia; And Others

    The guide outlines a course of study for elementary students on the history, geography, language, and general culture of China. Course objectives are to identify the major mountains, the major cities, and the types of climate affecting each region of China; locate and record on a time line the important events in the development of Chinese…

  6. Faculty Retention Study, 2002.

    ERIC Educational Resources Information Center

    South Texas Community Coll., McAllen. Office of Institutional Research and Effectiveness.

    This survey attempted to study factors important to making faculty decide to continue or terminate employment at South Texas Community College (STCC). Surveys were e-mailed to 276 full time, regular faculty and 170 adjunct faculty with valid STCC e-mail addresses. Although 54% (150) of the full time faculty responded to the survey, it remains a…

  7. Soil washing treatability study

    SciTech Connect

    Krstich, M.

    1995-12-01

    Soil washing was identified as a viable treatment process option for remediating soil at the FEMP Environmental Management Project (FEMP). Little information relative to the specific application and potential effectiveness of the soil washing process exists that applies to the types of soil at the FEMP. To properly evaluate this process option in conjunction with the ongoing FEMP Remedial Investigation/Feasibility Study (RI/FS), a treatability testing program was necessary to provide a foundation for a detailed technical evaluation of the viability of the process. In August 1991, efforts were initiated to develop a work plan and experimental design for investigating the effectiveness of soil washing on FEMP soil. In August 1992, the final Treatability Study Work Plan for Operable Unit 5: Soil Washing (DOE 1992) was issued. This document shall be referenced throughout the remainder of this report as the Treatability Study Work Plan (TSWP). The purpose of this treatability study was to generate data to support initial screening and the detailed analysis of alternatives for the Operable Unit 5 FS.

  8. Recycling Study Guide.

    ERIC Educational Resources Information Center

    Hallowell, Anne; And Others

    This study guide was designed to help teachers and students understand the problems surrounding solid wastes. It includes an overview of solid waste and recycling, a glossary, suggested activities and a list of resource publications, audiovisual materials and organizations. There are 19 activity suggestions included in this guide designed for use…

  9. National Indian Education Study

    ERIC Educational Resources Information Center

    Harvey, Karen Kay

    2006-01-01

    This report includes information from the National Indian Education Study of American Indian/Alaska Native students in grades 4 and 8 on the 2005 National Assessment of Education Progress (NAEP) in reading and mathematics. The national sample includes both public and private schools (i.e. Bureau of Indian Affairs, Department of Defense Education…

  10. Resources for Interdisciplinary Studies

    ERIC Educational Resources Information Center

    Klein, Julie Thompson

    2006-01-01

    Resources for interdisciplinary studies (IDS) appear in a multitude of print publications, online forums, and the "fugitive" or "gray" literature of conference papers, reports, and curriculum materials. The quantity is not surprising, since interdisciplinary discussions have expanded as new fields and approaches emerged across all domains of…

  11. Black Studies Year One.

    ERIC Educational Resources Information Center

    Long, Richard A.

    Though Dubois tried to begin a series of scientific studies on the Negro problem in America more than 70 years ago, only recently have attempts been made to present a true history of the Black man in institutions of higher learning. Until that time, the experience of the Black man was defined in Euro-American terms, or in most cases was completely…

  12. Environmental Modification: A Study

    ERIC Educational Resources Information Center

    Grinnell, Richard M., Jr.; Kyte, Nancy S.

    1975-01-01

    This study shows that environmental modification is a surprisingly intricate technique. This may account for its relatively low use and also for its more frequent use by MSW than non-MSW caseworkers. The findings indicate the need for further research on environmental modification. (Author)

  13. Fundamental studies in geodynamics

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1980-01-01

    Progress in modeling instantaneous plate kinematics is reviewed, with emphasis on recently developed models of present day plate motions derived by the systematic inversion of globally distributed data sets. Rivera plate motions, the Caribbean South American boundary, Indian plate deformation, Pacific-North America, seismicity and subduction processes, and the study of slow earthquakes and free oscillations are discussed.

  14. Plant Study Guide.

    ERIC Educational Resources Information Center

    Brynildson, Inga

    Appropriate for secondary school botany instruction, this study guide focuses on the important roles of plants in human lives. Following a rationale for learning the basic skills of a botanist, separate sections discuss the process sunlight undergoes during photosynthesis, the flow of energy in the food chain, alternative plant lifestyles, plant…

  15. Digital communications study

    NASA Technical Reports Server (NTRS)

    Boorstyn, R. R.

    1973-01-01

    Research is reported dealing with problems of digital data transmission and computer communications networks. The results of four individual studies are presented which include: (1) signal processing with finite state machines, (2) signal parameter estimation from discrete-time observations, (3) digital filtering for radar signal processing applications, and (4) multiple server queues where all servers are not identical.

  16. NEVADA ARSENIC STUDY

    EPA Science Inventory

    The effects of exposure to arsenic in U.S. drinking water at low levels are difficult to assess. In particular, studies of sufficient sample size on US populations exposed to arsenic in drinking water are few. Churchill County, NV (population 25000) has arsenic levels in drinki...

  17. Technion Libraries Systems Study.

    ERIC Educational Resources Information Center

    Thomas, Pauline

    This study is aimed at clarifying the objectives of the Technion Libraries' Systems, both within the Technion and as a national information resource, by defining the structure, organization, and methods to achieve these objectives. It considers Technion's future plans and current library practices as based on reports on the system, Technion…

  18. Study of Nursing Mothers

    ERIC Educational Resources Information Center

    Kazeem, Kolawole

    2006-01-01

    The participation of women in a higher education program depends on the extent to which the program takes into consideration the special needs of women--issues that have long plagued women's participation in education programs. In this study, we found that issues like childcare have not received any special consideration in the delivery of…

  19. URBAN STUDIES CENTER.

    ERIC Educational Resources Information Center

    HEBOUT, JOHN E.

    THE CENTER WORKS WITH RUTGERS UNIVERSITY TO MAKE USE OF URBAN STUDIES IN APPROPRIATE RESEARCH AND TEACHING PROGRAMS AND IN OTHER INTELLECTUAL SERVICES TO THE COMMUNITY. THE FIVE MAIN RESPONSIBILITIES OF THE CENTER - EXTENSION, RESEARCH AND EDUCATION, LIBRARY SERVICES, OPPORTUNITIES EXPANSION PROJECT, AND THE URBAN FELLOWSHIP PROGRAM - ARE…

  20. Plants Study Guide.

    ERIC Educational Resources Information Center

    Brynildson, Inga

    This study quide is intended to provide students with information about the types and functions of plants, along with some individual learning activities. The guide contains sections about: (1) the contributions of plants to life on earth and the benefits they afford to humanity; (2) the processes of photosynthesis and respiration; (3) the flow of…

  1. Micromechanical Study of Metals

    NASA Technical Reports Server (NTRS)

    Velikov, P. A.; Stchapov, N. P.; Lorenz, W. F.

    1945-01-01

    The Institut Scientifique Experimental des Transports at Moscow established toward the end of 1925 had since its inception included in its program the study of the mechanism of plastic deformation and the problems associated with it with reference to the materials of the means of transport. Before the program thus determined upon could be carried out, it was necessary to adopt a method of research, or, more exactly, a system of such methods. Because of the modest equipment of the laboratory of the recently established institute, the choice of any particular method was determined not only by the advantages it offered but also by the resources available. As a result of a series of studies and investigations, a method was determined upon which in this paper will be denoted as the micromechanical method. The underlying basis of this method is already known. As will be seen from the description that follows, the micromechanical method is merely a combination of the micrographic study of plastic deformations with mechanical tests on small specimens. It is a well-known fact that a number of investigators have largely employed and still are employing these two procedures and have thereby obtained good results. The authors of the present paper have found it useful to combine the two methods, by making the two studies simultaneously on the sane specimen.

  2. Why Indigenous Nations Studies?

    ERIC Educational Resources Information Center

    Porter, Robert; Yellow Bird, Michael

    2000-01-01

    The development of a new Indigenous Nations Studies program at the University of Kansas is described. Success depended on a critical mass of Indigenous and non-Indigenous faculty and students that had a sense of political and social justice and understood the need for institutional change. The biggest challenge was countering the entrenched…

  3. Resources for Women's Studies.

    ERIC Educational Resources Information Center

    Ridinger, Robert B.

    Over 120 bibliographies and other reference sources relevant to women's studies are identified in this annotated listing. Subjects include feminist scholarship, women in management, popular culture, autobiographies, other cultures and countries, history, lesbian women, women's education, the arts, politics, and rape. In addition to author, title,…

  4. HIM Correlational Study

    ERIC Educational Resources Information Center

    Powell, Evan R.

    1977-01-01

    This study uses two methods of analysis to examine the degree to which items within the cells of the Hill Interaction Matrix correlate. It is found that the table of specifications does not hold up. But the author recommends caution in interpreting this finding. (Author/BP)

  5. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1992-01-01

    The preparation is reported of carbon fiber composites using advanced polymer resins. Current and ongoing research activities include: powder towpreg process; weaving, braiding and stitching dry powder prepreg; advanced tow placement; and customized ATP towpreg. The goal of these studies is to produce advanced composite materials for automated part fabrication using textile and robotics technology in the manufacture of subsonic and supersonic aircraft.

  6. Educational Feasibility Study -- 1966.

    ERIC Educational Resources Information Center

    Hubbard, Ben C., Comp.; And Others

    By virtue of a Title III Elementary and Secondary Education Act grant, the feasibility of consolidating 7 Illinois high schools was studied. Areas of consideration were geographic characteristics, high school and elementary curriculum, and cost considerations relative to high school and elementary school buildings, curriculum, transportation,…

  7. Elementary Social Studies Program.

    ERIC Educational Resources Information Center

    Bay Shore School District, NY. Office of Instructional Services.

    The teacher-developed, elementary social studies program outlined here is a sequential curriculum that emphasizes educational objectives. It is intended to help students develop skills necessary for maintaining meaningful interpersonal relationships, recognize and cope with the problems of a rapidly changing world, and experience opportunities for…

  8. Outdoor Unified Studies.

    ERIC Educational Resources Information Center

    Liston, Louise

    Escalante (Utah) High School's outdoor unified studies field trip is a learning experience to be remembered. The four-day camping experience begins with pre-trip plans, pretests, and lecture/introductions to the Anasazi culture and to geologic formations to be visited. Horses (and equipment-carrying trucks) take the students into the desert to set…

  9. Speech Alarms Pilot Study

    NASA Technical Reports Server (NTRS)

    Sandor, A.; Moses, H. R.

    2016-01-01

    Currently on the International Space Station (ISS) and other space vehicles Caution & Warning (C&W) alerts are represented with various auditory tones that correspond to the type of event. This system relies on the crew's ability to remember what each tone represents in a high stress, high workload environment when responding to the alert. Furthermore, crew receive a year or more in advance of the mission that makes remembering the semantic meaning of the alerts more difficult. The current system works for missions conducted close to Earth where ground operators can assist as needed. On long duration missions, however, they will need to work off-nominal events autonomously. There is evidence that speech alarms may be easier and faster to recognize, especially during an off-nominal event. The Information Presentation Directed Research Project (FY07-FY09) funded by the Human Research Program included several studies investigating C&W alerts. The studies evaluated tone alerts currently in use with NASA flight deck displays along with candidate speech alerts. A follow-on study used four types of speech alerts to investigate how quickly various types of auditory alerts with and without a speech component - either at the beginning or at the end of the tone - can be identified. Even though crew were familiar with the tone alert from training or direct mission experience, alerts starting with a speech component were identified faster than alerts starting with a tone. The current study replicated the results from the previous study in a more rigorous experimental design to determine if the candidate speech alarms are ready for transition to operations or if more research is needed. Four types of alarms (caution, warning, fire, and depressurization) were presented to participants in both tone and speech formats in laboratory settings and later in the Human Exploration Research Analog (HERA). In the laboratory study, the alerts were presented by software and participants were

  10. Arc electrode interaction study

    NASA Technical Reports Server (NTRS)

    Zhou, X.; Berns, D.; Heberlein, J.

    1994-01-01

    The project consisted of two parts: (1) the cathode interaction studies which were a continuation of previous work and had the objective of increasing our understanding of the microscopic phenomena controlling cathode erosion in arc jet thrusters, and (2) the studies of the anode attachment in arc jet thrusters. The cathode interaction studies consisted of (1) a continuation of some modeling work in which the previously derived model for the cathode heating was applied to some specific gases and electrode materials, and (2) experimental work in which various diagnostics was applied to the cathode. The specific diagnostics used were observation of the cathode tip during arcing using a Laser Strobe Video system in conjunction with a tele-microscope, a monochromator with an optical multichannel analyzer for the determination of the cathode temperature distribution, and various ex situ materials analysis methods. The emphasis of our effort was shifted to the cathode materials analysis because a parallel project was in place during the second half of 1993 with a visiting scientist pursuing arc electrode materials studies. As a consequence, the diagnostic investigations of the arc in front of the cathode had to be postponed to the first half of 1994, and we are presently preparing these measurements. The results of last year's study showed some unexpected effects influencing the cathode erosion behavior, such as increased erosion away from the cathode tip, and our understanding of these effects should improve our ability to control cathode erosion. The arc jet anode attachment studies concentrated on diagnostics of the instabilities in subsonic anode attachment arc jet thrusters, and were supplemental measurements to work which was performed by one of the authors who spent the summer as an intern at NASA Lewis Research Center. A summary of the results obtained during the internship are included because they formed an integral part of the study. Two tasks for 1994, the

  11. Tire footprint studies

    NASA Astrophysics Data System (ADS)

    Chawla, Mangal; Medzorian, John

    1995-08-01

    This presentation covers the results of tire footprint studies conducted in the Landing Gear Development Facility of the USAF Wright Laboratory at the Wright Patterson Air force Base, OH. Tire footprint studies are essential in understanding tire wear mechanisms and computing tire tread wear rates. The power input into the tread is the driving force for tread wear. Variables needed for power input calculations include the footprint pressure and slip velocity distributions. Studies were performed on the effects of power input distributions due to vertical load, camber, yaw, inflation pressure, and tire construction. For the present study, two tire constructions, one radial and the other bias, were selected. These tires were for the F-16 Block 30 fighter aircraft, both of which were previously worn. The present study was limited to steady straight roll with a 14,000 lb vertical load, a 310 psi inflation pressure, and zero yaw and camber. All tests were conducted on the Tire Force Machine (TFM) with a specialized sensor plate with embedded pressure sensors (X, Y, and Z) and slip sensors (X and Y). All tests were conducted for a table speed of 1 in/s. Tests on the TFM show that the power intensity distributions and total power for both tire constructions are quite similar for straight roll. Later on, tests were also conducted on a modified dynamometer which was overlaid with a grit wear surface. The tire speed was maintained at 40 miles per hour and yaw was set to four degrees. Dynamometer tests showed that radial tires have more tread wear than the bias tire; however, in the field, radial tires have longer life.

  12. Photovoltaic evaluation study

    NASA Astrophysics Data System (ADS)

    Johnson, G.; Heikkilae, M.; Melasuo, T.; Spanner, S.

    Realizing the value and potential of PV-power as well as the growing need for increased cooperation and sharing of knowledge in the field of photovoltaics, FINNIDA and UNICEF decided to undertake a study of selected PV-projects. There were two main objectives for the study: To gather, compile, evaluate and share information on the photovoltaic technology appropriate to developing countries, and to promote the interest and competence of Finnish research institutes, consultants and manufacturers in photovoltaic development. For this purpose a joint evaluation of significant, primarily UN-supported projects providing for the basic needs of rural communities was undertaken. The Gambia and Kenya offered a variety of such projects, and were chosen as target countries for the study. The projects were chosen to be both comparable and complimentary. In the Gambia, the main subject was a partially integrated health and telecommunications project, but a long-operating drinking water pumping system was also studied. In Kenya, a health project in the Turkana area was examined, and also a large scale water pumping installation for fish farming. Field visits were made in order to verify and supplement the data gathered through document research and earlier investigations. Individual data gathering sheets for the project form the core of this study and are intended to give the necessary information in an organized and accessible format. The findings could practically be condensed into one sentence: PV-systems work very well, if properly designed and installed, but the resources and requirements of the recipients must be considered to a higher degree.

  13. Tire footprint studies

    NASA Technical Reports Server (NTRS)

    Chawla, Mangal; Medzorian, John

    1995-01-01

    This presentation covers the results of tire footprint studies conducted in the Landing Gear Development Facility of the USAF Wright Laboratory at the Wright Patterson Air force Base, OH. Tire footprint studies are essential in understanding tire wear mechanisms and computing tire tread wear rates. The power input into the tread is the driving force for tread wear. Variables needed for power input calculations include the footprint pressure and slip velocity distributions. Studies were performed on the effects of power input distributions due to vertical load, camber, yaw, inflation pressure, and tire construction. For the present study, two tire constructions, one radial and the other bias, were selected. These tires were for the F-16 Block 30 fighter aircraft, both of which were previously worn. The present study was limited to steady straight roll with a 14,000 lb vertical load, a 310 psi inflation pressure, and zero yaw and camber. All tests were conducted on the Tire Force Machine (TFM) with a specialized sensor plate with embedded pressure sensors (X, Y, and Z) and slip sensors (X and Y). All tests were conducted for a table speed of 1 in/s. Tests on the TFM show that the power intensity distributions and total power for both tire constructions are quite similar for straight roll. Later on, tests were also conducted on a modified dynamometer which was overlaid with a grit wear surface. The tire speed was maintained at 40 miles per hour and yaw was set to four degrees. Dynamometer tests showed that radial tires have more tread wear than the bias tire; however, in the field, radial tires have longer life.

  14. PET studies in epilepsy

    PubMed Central

    Sarikaya, Ismet

    2015-01-01

    Various PET studies, such as measurements of glucose, serotonin and oxygen metabolism, cerebral blood flow and receptor bindings are availabe for epilepsy. 18Fluoro-2-deoxyglucose (18F-FDG) PET imaging of brain glucose metabolism is a well established and widely available technique. Studies have demonstrated that the sensitivity of interictal FDG-PET is higher than interictal SPECT and similar to ictal SPECT for the lateralization and localization of epileptogenic foci in presurgical patients refractory to medical treatments who have noncontributory EEG and MRI. In addition to localizing epileptogenic focus, FDG-PET provide additional important information on the functional status of the rest of the brain. The main limitation of interictal FDG-PET is that it cannot precisely define the surgical margin as the area of hypometabolism usually extends beyond the epileptogenic zone. Various neurotransmitters (GABA, glutamate, opiates, serotonin, dopamine, acethylcholine, and adenosine) and receptor subtypes are involved in epilepsy. PET receptor imaging studies performed in limited centers help to understand the role of neurotransmitters in epileptogenesis, identify epileptic foci and investigate new treatment approaches. PET receptor imaging studies have demonstrated reduced 11C-flumazenil (GABAA-cBDZ) and 18F-MPPF (5-HT1A serotonin) and increased 11C-cerfentanil (mu opiate) and 11C-MeNTI (delta opiate) bindings in the area of seizure. 11C-flumazenil has been reported to be more sensitive than FDG-PET for identifying epileptic foci. The area of abnormality on GABAAcBDZ and opiate receptor images is usually smaller and more circumscribed than the area of hypometabolism on FDG images. Studies have demonstrated that 11C-alpha-methyl-L-tryptophan PET (to study synthesis of serotonin) can detect the epileptic focus within malformations of cortical development and helps in differentiating epileptogenic from non-epileptogenic tubers in patients with tuberous sclerosis complex

  15. Remote connector development study

    SciTech Connect

    Parazin, R.J.

    1995-05-01

    Plutonium-uranium extraction (PUREX) connectors, the most common connectors used at the Hanford site, offer a certain level of flexibility in pipe routing, process system configuration, and remote equipment/instrument replacement. However, these desirable features have inherent shortcomings like leakage, high pressure drop through the right angle bends, and a limited range of available pipe diameters that can be connect by them. Costs for construction, maintenance, and operation of PUREX connectors seem to be very high. The PUREX connector designs include a 90{degree} bend in each connector. This increases the pressure drop and erosion effects. Thus, each jumper requires at least two 90{degree} bends. PUREX connectors have not been practically used beyond 100 (4 in.) inner diameter. This study represents the results of a survey on the use of remote pipe-connection systems in US and foreign plants. This study also describes the interdependence between connectors, remote handling equipment, and the necessary skills of the operators.

  16. NASA study grants

    NASA Astrophysics Data System (ADS)

    To expand human exploration of the Solar System, the Office of Exploration of the National Aeronautics and Space Administration has awarded 20 contracts for ideas, concepts, devices, systems, and trajectory, operation and implementation plans. Winning proposals came from five industry-related firms, two organizations in the space-support business, and thirteen universities; they were chosen from 115 entries.Geophysical studies to be supported include site characterization of the Oregon moonbase (Oregon L-5 Society, Inc., Oregon City), evolution of design alternatives for exploration of Mars by balloon (Titan Systems, Inc., San Diego, Calif.), design considerations of a lunar production plant (Boston University, Chestnut Hill, Mass.), planetary materials and resource utilization (Michigan Technological University, Houghton), Mars tethered sample return study (University of Colorado, Boulder), Teleprospector, a teleoperated robotic field geologist (University of New Mexico, Albuquerque), and the International Lunar Polar Orbiter (International Space University, Boston, Mass.).

  17. Geological science needs studied

    NASA Astrophysics Data System (ADS)

    The Geological Sciences Board of the National Academy of Science is conducting a study of the trends, needs, and priorities of the geological sciences for the 1980s. Many organizations and individuals already have been contacted regarding this task; however, in order to ensure that the forthcoming report is based broadly on ideas from the scientific community, the Geological Sciences Board solicits the thoughts of AGU members about the substance of the study. Please send your questions and comments by early this fall to William Dickinson, chairman of the Geological Sciences Board, National Academy of Sciences, Room 69, 2101 Constitution Ave., N.W., Washington, D.C. 20418. A draft report is expected in January 1983.

  18. Advanced life support study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Summary reports on each of the eight tasks undertaken by this contract are given. Discussed here is an evaluation of a Closed Ecological Life Support System (CELSS), including modeling and analysis of Physical/Chemical Closed Loop Life Support (P/C CLLS); the Environmental Control and Life Support Systems (ECLSS) evolution - Intermodule Ventilation study; advanced technologies interface requirements relative to ECLSS; an ECLSS resupply analysis; the ECLSS module addition relocation systems engineering analysis; an ECLSS cost/benefit analysis to identify rack-level interface requirements of the alternate technologies evaluated in the ventilation study, with a comparison of these with the rack level interface requirements for the baseline technologies; advanced instrumentation - technology database enhancement; and a clean room survey and assessment of various ECLSS evaluation options for different growth scenarios.

  19. Space Studies Board, 1994

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This 1994 report of the Space Studies Board of the National Research Council summarizes the charter and organization of the board, activities and membership, major and short reports, and congressional testimony. A cumulative bibliography of the Space Studies (formerly Space Science) Board and its committees is provided. An appendix contains reports of the panel to review Earth Observing System Data and Information System (EOSDIS) plans. Major reports cover scientific opportunities in the human exploration of space, the dichotomy between funding and effectiveness in space physics, an integrated strategy for the planetary sciences for the years 1995-2010, and Office of Naval Research (ONR) research opportunities in upper atmospheric sciences. Short reports cover utilization of the space station, life and microgravity sciences and the space station program, Space Infrared Telescope Facility and the Stratospheric Observatory for Infrared Astronomy, and the Advanced X-ray Astrophysics Facility and Cassini Saturn Probe.

  20. Industrial cogeneration case studies

    NASA Astrophysics Data System (ADS)

    Limaye, D. R.; Isser, S.; Hinkle, B.; Friedman, N. R.

    1980-09-01

    Studies were performed on a number of operating cogeneration systems to determine application, economics, and attitudes of industrial and utility executives toward cogeneration. A literature survey was conducted and an identification of candidate cogeneration sites was carried out. This was followed by a screening of these sites down to 20 to 30 candidate sites. The screening was carried out on the basis of cogeneration capacity, geographical diversity, generation type, and industrial diversity. The remaining sites were contacted as to their willingness to work with EPRI, and an industrial questionnaire was developed on technical, economic, and institutional cogeneration issues. Each of the seventeen sites was visited during this task. A utility questionnaire was developed and utilities with cogeneration systems studied in this survey were contacted as to their attitudes toward cogeneration. In addition, a compilation of a list of operating cogeneration systems was performed.

  1. Fundamental Pyrolysis Studies

    SciTech Connect

    Milne, T. A.; Evans, R. J.; Soltys, M. N.

    1983-03-01

    Progress on the direct mass spectrometric sampling of pyrolysis products from wood and its constituents is described for the period from June 1982 to February 1983. A brief summary and references to detailed reports, of the qualitative demonstration of our approach to the study of the separated processes of primary and secondary pyrolysis is presented. Improvements and additions to the pyrolysis and data acquisition systems are discussed and typical results shown. Chief of these are a heated-grid pyrolysis system for controlled primary pyrolysis and a sheathed flame arrangement for secondary cracking studies. Qualitative results of the secondary cracking of cellulose, lignin, and wood are shown as are comparisons with the literature for the pyrolysis spectra of cellulose, lignin, and levoglucosan. 'Fingerprints' for a number of materials are shown, with spectra taken under carefully controlled conditions so that sensitivity calibrations for different compounds, now being determined, can be applied.

  2. LOXT mirror design study

    NASA Technical Reports Server (NTRS)

    Vanspeybroeck, L.; Antrim, W.; Boyd, D.; Giacconi, R.; Sinnamon, G.; Stille, F.

    1972-01-01

    The final report for the large orbiting X-ray telescope (LOXT) high resolution mirror design study is presented. The following tasks were performed: (1) Generation of a reference and alternate preliminary design for the LOXT high resolution mirror assembly, which will meet the LOXT scientific requirements, and are within the present state of the art of materials and fabrication techniques. (2) Measurement, in X-rays, of the scattering properties of a variety of optical flats, embodying materials, coatings, and polishing techniques which might be applicable to the flight configuration LOXT high resolution mirror. (3) Preparation of a procurement specification for a paraboloid test mirror of the size of the innermost paraboloid of the high resolution mirror assembly, including the design requirements for the reference design evolved from this preliminary design study. The results of the engineering and scientific analysis and the conclusions drawn are presented. The procurement specification for the test mirror is included.

  3. EOS mapping accuracy study

    NASA Technical Reports Server (NTRS)

    Forrest, R. B.; Eppes, T. A.; Ouellette, R. J.

    1973-01-01

    Studies were performed to evaluate various image positioning methods for possible use in the earth observatory satellite (EOS) program and other earth resource imaging satellite programs. The primary goal is the generation of geometrically corrected and registered images, positioned with respect to the earth's surface. The EOS sensors which were considered were the thematic mapper, the return beam vidicon camera, and the high resolution pointable imager. The image positioning methods evaluated consisted of various combinations of satellite data and ground control points. It was concluded that EOS attitude control system design must be considered as a part of the image positioning problem for EOS, along with image sensor design and ground image processing system design. Study results show that, with suitable efficiency for ground control point selection and matching activities during data processing, extensive reliance should be placed on use of ground control points for positioning the images obtained from EOS and similar programs.

  4. Studying the Human Microbiota.

    PubMed

    Walker, Alan W

    2016-01-01

    There are a range of methodologies available to study the human microbiota, ranging from traditional approaches such as culturing through to state-of-the-art developments in next generation DNA sequencing technologies. The advent of molecular techniques in particular has opened up tremendous new avenues for research, and has galvanised interest in the study of our microbial inhabitants. Given the dazzling array of available options, however, it is important to understand the inherent advantages and limitations of each technique so that the best approach can be employed to address the particular research objective. In this chapter we cover some of the most widely used current techniques in human microbiota research and highlight the particular strengths and caveats associated with each approach. PMID:27161348

  5. Heliostat cost optimization study

    NASA Astrophysics Data System (ADS)

    von Reeken, Finn; Weinrebe, Gerhard; Keck, Thomas; Balz, Markus

    2016-05-01

    This paper presents a methodology for a heliostat cost optimization study. First different variants of small, medium sized and large heliostats are designed. Then the respective costs, tracking and optical quality are determined. For the calculation of optical quality a structural model of the heliostat is programmed and analyzed using finite element software. The costs are determined based on inquiries and from experience with similar structures. Eventually the levelised electricity costs for a reference power tower plant are calculated. Before each annual simulation run the heliostat field is optimized. Calculated LCOEs are then used to identify the most suitable option(s). Finally, the conclusions and findings of this extensive cost study are used to define the concept of a new cost-efficient heliostat called `Stellio'.

  6. World Biofuels Study

    SciTech Connect

    Alfstad,T.

    2008-10-01

    This report forms part of a project entitled 'World Biofuels Study'. The objective is to study world biofuel markets and to examine the possible contribution that biofuel imports could make to help meet the Renewable Fuel Standard (RFS) of the Energy Independence and Security Act of 2007 (EISA). The study was sponsored by the Biomass Program of the Assistant Secretary for Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy. It is a collaborative effort among the Office of Policy and International Affairs (PI), Department of Energy and Oak Ridge National Laboratory (ORNL), National Renewable Energy Laboratory (NREL) and Brookhaven National Laboratory (BNL). The project consisted of three main components: (1) Assessment of the resource potential for biofuel feedstocks such as sugarcane, grains, soybean, palm oil and lignocellulosic crops and development of supply curves (ORNL). (2) Assessment of the cost and performance of biofuel production technologies (NREL). (3) Scenario-based analysis of world biofuel markets using the ETP global energy model with data developed in the first parts of the study (BNL). This report covers the modeling and analysis part of the project conducted by BNL in cooperation with PI. The Energy Technology Perspectives (ETP) energy system model was used as the analytical tool for this study. ETP is a 15 region global model designed using the MARKAL framework. MARKAL-based models are partial equilibrium models that incorporate a description of the physical energy system and provide a bottom-up approach to study the entire energy system. ETP was updated for this study with biomass resource data and biofuel production technology cost and performance data developed by ORNL and NREL under Tasks 1 and 2 of this project. Many countries around the world are embarking on ambitious biofuel policies through renewable fuel standards and economic incentives. As a result, the global biofuel demand is expected to grow very rapidly over

  7. Payload training methodology study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The results of the Payload Training Methodology Study (PTMS) are documented. Methods and procedures are defined for the development of payload training programs to be conducted at the Marshall Space Flight Center Payload Training Complex (PCT) for the Space Station Freedom program. The study outlines the overall training program concept as well as the six methodologies associated with the program implementation. The program concept outlines the entire payload training program from initial identification of training requirements to the development of detailed design specifications for simulators and instructional material. The following six methodologies are defined: (1) The Training and Simulation Needs Assessment Methodology; (2) The Simulation Approach Methodology; (3) The Simulation Definition Analysis Methodology; (4) The Simulator Requirements Standardization Methodology; (5) The Simulator Development Verification Methodology; and (6) The Simulator Validation Methodology.

  8. Options Study - Phase II

    SciTech Connect

    R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin

    2010-09-01

    The Options Study has been conducted for the purpose of evaluating the potential of alternative integrated nuclear fuel cycle options to favorably address the issues associated with a continuing or expanding use of nuclear power in the United States. The study produced information that can be used to inform decisions identifying potential directions for research and development on such fuel cycle options. An integrated nuclear fuel cycle option is defined in this study as including all aspects of the entire nuclear fuel cycle, from obtaining natural resources for fuel to the ultimate disposal of used nuclear fuel (UNF) or radioactive wastes. Issues such as nuclear waste management, especially the increasing inventory of used nuclear fuel, the current uncertainty about used fuel disposal, and the risk of nuclear weapons proliferation have contributed to the reluctance to expand the use of nuclear power, even though it is recognized that nuclear power is a safe and reliable method of producing electricity. In this Options Study, current, evolutionary, and revolutionary nuclear energy options were all considered, including the use of uranium and thorium, and both once-through and recycle approaches. Available information has been collected and reviewed in order to evaluate the ability of an option to clearly address the challenges associated with the current implementation and potential expansion of commercial nuclear power in the United States. This Options Study is a comprehensive consideration and review of fuel cycle and technology options, including those for disposal, and is not constrained by any limitations that may be imposed by economics, technical maturity, past policy, or speculated future conditions. This Phase II report is intended to be used in conjunction with the Phase I report, and much information in that report is not repeated here, although some information has been updated to reflect recent developments. The focus in this Options Study was to

  9. [Twin studies in psychiatry].

    PubMed

    Kringlen, E

    1999-09-20

    Twin research in medicine and psychology has blossomed during the last decades. A brief presentation of twin research methods is given, followed by a review of psychiatric studies, particularly Norwegian ones. The Nordic investigations are of great importance because many of these studies have been able to avoid shortcomings in sampling by linking national twin registers to disease registers. This procedure is of consequence for the estimation of heritability. Twin research shows that the genetic contribution to Alzheimer's disease, manic-depressive (bipolar) disorder, schizophrenia and childhood autism is relatively strong, whereas genetic factors play a minor role in common depressions, anxiety and somatoform disorders, and alcohol abuse. Since the concordance rates are far from 100 percent in most of these illnesses, environmental factors must also be important. PMID:10533417

  10. RF Gun Optimization Study

    SciTech Connect

    A. S. Hofler; P. Evtushenko; M. Krasilnikov

    2007-08-01

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. RF and SRF gun design is further complicated because the bunches are space charge dominated and require additional emittance compensation. A genetic algorithm has been successfully used to optimize DC photo injector designs for Cornell* and Jefferson Lab**, and we propose studying how the genetic algorithm techniques can be applied to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize gun designs that have been benchmarked with beam measurements and simulation.

  11. E85 Dispenser Study

    SciTech Connect

    Moriarty, K.; Johnson, C.; Sears, T.; Bergeron, P.

    2009-12-01

    This study reviews E85 dispensing infrastructure advances and issues and evaluates the geographic concentration of flexible fuel vehicles (FFVs), E85 stations, ethanol production facilities, and E85 suppliers. Costs, space, financial incentives, and barriers to adding E85 fueling equipment at existing stations are also assessed. This study found that E85 is increasingly available in the U.S. in half of the states; however, the other half have minimal or no E85 fueling options. Despite these gains, E85 is only available at 1% of U.S. gasoline stations. Ethanol production reached 9.5 billion gallons in 2008, but less than 1% is consumed as E85. FFVs have not reached a significant concentration in any county, metropolitan area, or state.

  12. Repository seals requirement study

    SciTech Connect

    1997-11-03

    The Yucca Mountain Site Characterization Project, managed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) is conducting investigations to support the Viability Assessment and the License Application for a high-level nuclear waste repository at Yucca Mountain, Nevada. The sealing subsystem is part of the Yucca Mountain Waste Isolation System. The Yucca Mountain Site Characterization Project is currently evaluating the role of the sealing subsystem (shaft, ramp and exploratory borehole seals) in achieving the overall performance objectives for the Waste Isolation System. This report documents the results of those evaluations. The objective of the study is to provide water or air flow performance based requirements for shafts, ramps, and exploratory boreholes located near the repository. Recommendations, as appropriate, are provided for developing plans, seals component testing, and other studies relating to sealing.

  13. Study Thermographic Flaw Detection

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Workman, Gary L.

    1996-01-01

    The development of thermographic inspection methods for use on aerospace structures is under investigation. Several different material systems, structural geometries and defect types have been included in this study so as to establish a baseline from which future Infrared Thermography(IRT) testing can be made. This study examines various thermal loading techniques in an attempt to enhance the likelihood of capturing and identifying critically sized flaws under 'non laboratory' actual working conditions. Qualification techniques and calibration standards are also being investigated to standardize the thermographic method. In conjunction with the thermographic inspections, advanced image processing techniques including digital filtering and neural networks have been investigated to increase the ability of detecting and sizing flaws. Here, the digitized thermographic images are mathematically manipulated through various filtering techniques and/or artificial neural mapping schemes to enhance its overall quality, permitting accurate flaw identification even when the signal-to-noise ratio is low.

  14. Rotating Gravity Gradiometer Study

    NASA Technical Reports Server (NTRS)

    Forward, R. L.

    1976-01-01

    The application of a Rotating Gravity Gradiometer (RGG) system on board a Lunar Polar Orbiter (LPO) for the measurement of the Lunar gravity field was investigated. A data collection simulation study shows that a gradiometer will give significantly better gravity data than a doppler tracking system for the altitudes under consideration for the LOP, that the present demonstrated sensitivity of the RGG is adequate for measurement of the Lunar gravity gradient field, and that a single RGG instrument will provide almost as much data for geophysical interpretation as an orthogonal three axis RGG system. An engineering study of the RGG sensor/LPO spacecraft interface characteristics shows that the RGG systems under consideration are compatible with the present models of the LPO spacecraft.

  15. Simulation verification techniques study

    NASA Technical Reports Server (NTRS)

    Schoonmaker, P. B.; Wenglinski, T. H.

    1975-01-01

    Results are summarized of the simulation verification techniques study which consisted of two tasks: to develop techniques for simulator hardware checkout and to develop techniques for simulation performance verification (validation). The hardware verification task involved definition of simulation hardware (hardware units and integrated simulator configurations), survey of current hardware self-test techniques, and definition of hardware and software techniques for checkout of simulator subsystems. The performance verification task included definition of simulation performance parameters (and critical performance parameters), definition of methods for establishing standards of performance (sources of reference data or validation), and definition of methods for validating performance. Both major tasks included definition of verification software and assessment of verification data base impact. An annotated bibliography of all documents generated during this study is provided.

  16. Advanced Motor Drives Studies

    NASA Technical Reports Server (NTRS)

    Ehsani, M.; Tchamdjou, A.

    1997-01-01

    This report presents an evaluation of advanced motor drive systems as a replacement for the hydrazine fueled APU units. The replacement technology must meet several requirements which are particular to the space applications and the Orbiter in general. Some of these requirements are high efficiency, small size, high power density. In the first part of the study several motors are compared, based on their characteristics and in light of the Orbiter requirements. The best candidate, the brushless DC is chosen because of its particularly good performance with regards to efficiency. Several power electronics drive technologies including the conventional three-phase hard switched and several soft-switched inverters are then presented. In the last part of the study, a soft-switched inverter is analyzed and compared to its conventional hard-switched counterpart. Optimal efficiency is a basic requirement for space applications and the soft-switched technology represents an unavoidable trend for the future.

  17. Skylab Earth Observation Studies

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This concept illustrates Skylab Earth observation studies, an Earth Resources Experiment Package (EREP). EREP was designed to explore the use of the widest possible portion of the electromagnetic spectrum for Earth resource investigations with sensors that recorded data in the visible, infrared, and microwave spectral regions. Resources subject to this study included a capability of mapping Earth resources and land uses, crop and forestry cover, health of vegetation, types of soil, water storage in snow pack, surface or near-surface mineral deposits, sea surface temperature, and the location of likely feeding areas for fish, etc. A significant feature of EREP was the ability of man to operate the sensors in a laboratory fashion.

  18. Protein crystallization studies

    NASA Technical Reports Server (NTRS)

    Lyne, James Evans

    1996-01-01

    The Structural Biology laboratory at NASA Marshall Spaceflight Center uses x-ray crystallographic techniques to conduct research into the three-dimensional structure of a wide variety of proteins. A major effort in the laboratory involves an ongoing study of human serum albumin (the principal protein in human plasma) and its interaction with various endogenous substances and pharmaceutical agents. Another focus is on antigenic and functional proteins from several pathogenic organisms including the human immunodeficiency virus (HIV) and the widespread parasitic genus, Schistosoma. My efforts this summer have been twofold: first, to identify clinically significant drug interactions involving albumin binding displacement and to initiate studies of the three-dimensional structure of albumin complexed with these agents, and secondly, to establish collaborative efforts to extend the lab's work on human pathogens.

  19. Electroencephalographic studies of sleep

    NASA Technical Reports Server (NTRS)

    Webb, W. B.; Agnew, H. W., Jr.

    1975-01-01

    Various experimental studies on sleep are described. The following areas are discussed: (1) effect of altered day length on sleep, (2) effect of a partial loss of sleep on subsequent nocturnal sleep; (3) effect of rigid control over sleep-wake-up times; (4) sleep and wakefulness in a time-free environment; (5) distribution of spindles during a full night of sleep; and (6) effect on sleep and performance of swiftly changing shifts of work.

  20. Human exploration mission studies

    NASA Technical Reports Server (NTRS)

    Cataldo, Robert L.

    1990-01-01

    This paper describes several case studies of human space exploration, considered by the NASA's Office of Exploration in 1988. Special attention is given to the mission scenarios, the critical technology required in these expeditions, and the extraterrestrial power requirements of significant system elements. The cases examined include a manned expedition to Phobos, the inner Martian moon; a human expedition to Mars; the Lunar Observatory; and a lunar outpost to early Mars evolution.

  1. Electron microscope studies

    SciTech Connect

    Crewe, A.V.; Kapp, O.H.

    1991-06-01

    This year our laboratory has continued to make progress in the design of electron-optical systems, in the study of structure-function relationships of large multi-subunit proteins, in the development of new image processing software and in achieving a workable sub-angstrom STEM. We present an algebraic approach to the symmetrical Einzel (unipotential) lens wherein we simplify the analysis by specifying a field shape that meets some preferred set of boundary or other conditions and then calculate the fields. In a second study we generalize this approach to study of three element electrostatic lenses of which the symmetrical Einzel lens is a particular form. The purpose is to develop a method for assisting in the design of a lens for a particular purpose. In our biological work we study a stable and functional dodecameric complex of globin chains from the hemoglobin of Lumbricus terrestris. This is a complex lacking the linker'' subunit first imaged in this lab and required for maintenance of the native structure. In addition, we do a complete work-up on the hemoglobin of the marine polychaete Eudistylia vancouverii demonstrating the presence of a hierarchy of globin complexes. We demonstrate stable field-emission in the sub-angstrom STEM and the preliminary alignment of the beam. We continue our exploration of a algorithms for alignment of sequences of protein and DNA. Our computer facilities now include four second generation RISC workstations and we continue to take increasing advantage of the floating-point and graphical performance of these devices.

  2. Mars Rover RTG Study

    SciTech Connect

    Schock, Alfred

    1989-08-25

    This report summarizes the results of a Radioisotope Thermoelectric Generator (RTG) design study conducted by Fairchild Space Company at the direction of the U.S. Department of Energy's Office of SpecialApplications, in suppport of the Mars Rover and Sample Return mission under investigation at NASA's Jet Propulsion Laboratory. The report is a rearranged, updated, and significantly expanded amalgam of three interrelated papers presented at the 24th Intersocity Energy Conversion Engineering Conference (IECEC) at Arlington, Virginia, on August 10, 1989.

  3. HIRIS performance study

    NASA Technical Reports Server (NTRS)

    Kerekes, John P.; Landgrebe, David A.

    1989-01-01

    The remote sensing system simulation is used to study a proposed sensor concept. An overview of the instrument and its parameters is presented, along with the model of the instrument as implemented in the simulation. Signal-to-noise levels of the instrument under a variety of system configurations are presented and discussed. Classification performance under these varying configurations is also shown, along with relationships between signal-to-noise ratios, feature selection, and classification performance.

  4. Protein Crystal Quality Studies

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Eddie Snell, Post-Doctoral Fellow the National Research Council (NRC) uses a reciprocal space mapping diffractometer for macromolecular crystal quality studies. The diffractometer is used in mapping the structure of macromolecules such as proteins to determine their structure and thus understand how they function with other proteins in the body. This is one of several analytical tools used on proteins crystallized on Earth and in space experiments. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  5. NASA Propagation Studies Website

    NASA Technical Reports Server (NTRS)

    Angkasa, Krisjani S.

    1996-01-01

    This paper describes an Internet website which provides information to enable the development of new commerical satellite systems and services by providing timely data and models about the propagation of satellite radio signals. In partnership with industry and academia, the program leverages NASA assets, currently the Advanced Communications Technology Satellite (ACTS), to obtain propagation data. The findings of the study are disseminated through refereed journals, NASA reference publications, workshops, electronic media, and direct interface with industry.

  6. Advanced studies program overview

    NASA Technical Reports Server (NTRS)

    Ahlf, Peter R.

    1991-01-01

    The topics covered are presented in view graph form and include the following: (1) Space Station Engineering; (2) level 1 engineering organization; (3) advanced studies program organization; (4) NASA Center support areas; (5) work breakdown; (6) Space Station Freedom (SSF) Program Phases; (7) distributed systems evolution; (8) Space Shuttle ET mating analogy to on-orbit tank mating; (9) reference growth concept; (10) technology assessment process; (11) SSF technology priorities; (12) accomplishments; and (13) near term direction.

  7. Lighting Retrofit Study

    SciTech Connect

    Kromer, S.; Morse, O.; Siminovitch, M.

    1991-09-01

    The Lighting Retrofit Study was an effort to determine the most cost-effective methods of retrofitting several configurations of lighting systems at Lawrence Berkeley Laboratory (LBL) and Lawrence Livermore National Laboratory (LLNL). We developed a test protocol to compare a variety of lighting technologies for their applicability in labs and offices and designed and constructed a novel lighting contrast potential meter to allow for comparison of lighting quality as well as quantity.

  8. Solar Coronal Structure Study

    NASA Technical Reports Server (NTRS)

    Bruner, Marilyn E.; Saba, Julia; Strong, Keith; Nitta, Nariaki; Harvey, Karen

    1997-01-01

    The subject of this investigation is the study the physics of the solar corona through the analysis of the EUV and UV data produced by two flights (12 May 1992 and 25 April 1994) of the Lockheed Solar Plasma Diagnostics Experiment (SPDE) sounding rocket payload, in combination with Yohkoh and groundbased data. These joint datasets are useful for understanding the physical state of the solar atmosphere from the photosphere to the corona at the time of the rocket flights. Each rocket flight produced both spectral and imaging data. Highlights of this initial year of the contract included compilation, scaling and co-alignment of image sets, substantial progress on the Bright Point study, initial work on the Active Region and Large Scale Structure studies, DRSC slit-aspect determination work and calibration activities. One paper was presented at the 1997 Annual Meeting of the AAS/SPD in Bozeman, Montana. An initial set of calibrated spectra were placed into the public domain via the World Wide Web. Three Quarterly Progress Reports have been submitted; progress for the fourth quarter of the contract is summarized in this Final Contract Report. The intent of the investigation is to compare the physics of small- and medium-scale structure with that of large-scale structures with weak fields. A study has been identified in each size domain. The calibration of the rocket data forms an important element of the work. Of equal importance is the slit-aspect solution, which determines the correspondence between locations along the spectrograph slit and points on the solar disk.

  9. Electrochemical corrosion studies

    NASA Technical Reports Server (NTRS)

    Knockemus, W. W.

    1986-01-01

    The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel.

  10. Space Station evolution study

    NASA Technical Reports Server (NTRS)

    Evans, David B.

    1993-01-01

    This is the Space Station Freedom (SSF) Evolution Study 1993 Final Report, performed under NASA Contract NAS8-38783, Task Order 5.1. This task examined: (1) the feasibility of launching current National Space Transportation System (NSTS) compatible logistics elements on expendable launch vehicles (ELV's) and the associated modifications, and (2) new, non-NSTS logistics elements for launch on ELV's to augment current SSF logistics capability.

  11. Integrated optics technology study

    NASA Technical Reports Server (NTRS)

    Chen, B.

    1982-01-01

    The materials and processes available for the fabrication of single mode integrated electrooptical components are described. Issues included in the study are: (1) host material and orientation, (2) waveguide formation, (3) optical loss mechanisms, (4) wavelength selection, (5) polarization effects and control, (6) laser to integrated optics coupling,(7) fiber optic waveguides to integrated optics coupling, (8) souces, (9) detectors. The best materials, technology and processes for fabrication of integrated optical components for communications and fiber gyro applications are recommended.

  12. Speech Alarms Pilot Study

    NASA Technical Reports Server (NTRS)

    Sandor, Aniko; Moses, Haifa

    2016-01-01

    Speech alarms have been used extensively in aviation and included in International Building Codes (IBC) and National Fire Protection Association's (NFPA) Life Safety Code. However, they have not been implemented on space vehicles. Previous studies conducted at NASA JSC showed that speech alarms lead to faster identification and higher accuracy. This research evaluated updated speech and tone alerts in a laboratory environment and in the Human Exploration Research Analog (HERA) in a realistic setup.

  13. Computerizing Audit Studies

    PubMed Central

    Lahey, Joanna N.; Beasley, Ryan A.

    2014-01-01

    This paper briefly discusses the history, benefits, and shortcomings of traditional audit field experiments to study market discrimination. Specifically it identifies template bias and experimenter bias as major concerns in the traditional audit method, and demonstrates through an empirical example that computerization of a resume or correspondence audit can efficiently increase sample size and greatly mitigate these concerns. Finally, it presents a useful meta-tool that future researchers can use to create their own resume audits. PMID:24904189

  14. Depth Optimization Study

    DOE Data Explorer

    Kawase, Mitsuhiro

    2009-11-22

    The zipped file contains a directory of data and routines used in the NNMREC turbine depth optimization study (Kawase et al., 2011), and calculation results thereof. For further info, please contact Mitsuhiro Kawase at kawase@uw.edu. Reference: Mitsuhiro Kawase, Patricia Beba, and Brian Fabien (2011), Finding an Optimal Placement Depth for a Tidal In-Stream Conversion Device in an Energetic, Baroclinic Tidal Channel, NNMREC Technical Report.

  15. Fundamental studies in geodynamics

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.; Hager, B. H.; Kanamori, H.

    1981-01-01

    Research in fundamental studies in geodynamics continued in a number of fields including seismic observations and analysis, synthesis of geochemical data, theoretical investigation of geoid anomalies, extensive numerical experiments in a number of geodynamical contexts, and a new field seismic volcanology. Summaries of work in progress or completed during this report period are given. Abstracts of publications submitted from work in progress during this report period are attached as an appendix.

  16. Master Study: Ceramics

    ERIC Educational Resources Information Center

    Clark, Kelly

    2004-01-01

    In painting and drawing classes, it is typical to ask students to work directly from a master. It is one way to study composition techniques, and to become familiar with classical style firsthand. In museums, easels are set up as artists work, not in an attempt to copy or plagiarize, but in an attempt to be part of history by participating in it.…

  17. Software breadboard study

    NASA Technical Reports Server (NTRS)

    Nuckolls, C.; Frank, Mark

    1990-01-01

    The overall goal of this study was to develop new concepts and technology for the Comet Rendezvous Asteroid Flyby (CRAF), Cassini, and other future deep space missions which maximally conform to the Functional Specification for the NASA X-Band Transponder (NXT), FM513778 (preliminary, revised July 26, 1988). The study is composed of two tasks. The first task was to investigate a new digital signal processing technique which involves the processing of 1-bit samples and has the potential for significant size, mass, power, and electrical performance improvements over conventional analog approaches. The entire X-band receiver tracking loop was simulated on a digital computer using a high-level programming language. Simulations on this 'software breadboard' showed the technique to be well-behaved and a good approximation to its analog predecessor from threshold to strong signal levels in terms of tracking-loop performance, command signal-to-noise ratio and ranging signal-to-noise ratio. The successful completion of this task paves the way for building a hardware breadboard, the recommended next step in confirming this approach is ready for incorporation into flight hardware. The second task in this study was to investigate another technique which provides considerable simplification in the synthesis of the receiver first LO over conventional phase-locked multiplier schemes and in this approach, provides down-conversion for an S-band emergency receive mode without the need of an additional LO. The objective of this study was to develop methodology and models to predict the conversion loss, input RF bandwidth, and output RF bandwidth of a series GaAs FET sampling mixer and to breadboard and test a circuit design suitable for the X and S-band down-conversion applications.

  18. Ocean circulation studies

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.

    1984-01-01

    Remotely sensed signatures of ocean surface characteristics from active and passive satellite-borne radiometers in conjunction with in situ data were utilized to examine the large scale, low frequency circulation of the world's oceans. Studies of the California Current, the Gulf of California, and the Kuroshio Extension Current in the western North Pacific were reviewed briefly. The importance of satellite oceanographic tools was emphasized.

  19. Laser Initiated Actuator study

    SciTech Connect

    Watson, B.

    1991-06-27

    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  20. Electron microscope studies

    NASA Astrophysics Data System (ADS)

    Crewe, A. V.; Kapp, O. H.

    1991-06-01

    This year our laboratory has continued to make progress in the design of electron-optical systems, in the study of structure-function relationships of large multi-subunit proteins, in the development of new image processing software and in achieving a workable sub-angstrom STEM. We present an algebraic approach to the symmetrical Einzel (unipotential) lens wherein we simplify the analysis by specifying a field shape that meets some preferred set of boundary or other conditions and then calculate the fields. In a second study we generalize this approach to study of three element electrostatic lenses of which the symmetrical Einzel lens is a particular form. The purpose is to develop a method for assisting in the design of a lens for a particular purpose. In our biological work we study a stable and functional dodecameric complex of globin chains from the hemoglobin of Lumbricus terrestris. This is a complex lacking the 'linker' subunit first imaged in this lab and required for maintenance of the native structure. In addition, we do a complete work-up on the hemoglobin of the marine polychaete Eudistylia vancouverii, demonstrating the presence of a hierarchy of globin complexes. We demonstrate stable field-emission in the sub-angstrom STEM and the preliminary alignment of the beam. We continue our exploration of a algorithms for alignment of sequences of protein and DNA. Our computer facilities now include four second generation RISC workstations and we continue to take increasing advantage of the floating-point and graphical performance of these devices.