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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. A computational NQR study on the hydrogen-bonded lattice of cytosine-5-acetic acid.

    PubMed

    Mirzaei, Mahmoud; Hadipour, Nasser L

    2008-04-15

    A computational study at the level of density functional theory (DFT) employing 6-311++G** standard basis set was carried out to evaluate nuclear quadrupole resonance (NQR) spectroscopy parameters in cytosine-5-acetic acid (C5AA). Since the electric field gradient (EFG) tensors are very sensitive to the electrostatic environment at the sites of quadruple nuclei, the most possible interacting molecules with the target one were considered in a five-molecule model system of C5AA using X-ray coordinates transforming. The hydrogen atoms positions were optimized and two model systems of original and H-optimized C5AA were considered in NQR calculations. The calculated EFG tensors at the sites of (17)O, (14)N, and (2)H nuclei were converted to their experimentally measurable parameters, quadrupole coupling constants and asymmetry parameters. The evaluated NQR parameters reveal that the nuclei in original and H-optimized systems contribute to different hydrogen bonding (HB) interaction. The comparison of calculated parameters between optimized isolated gas-phase and crystalline monomer also shows the relationship between the structural deformation and NQR parameters in C5AA. The basis set superposition error (BSSE) calculations yielded no significant errors for employed basis set in the evaluation of NQR parameters. All the calculations were performed by Gaussian 98 package of program. PMID:17926341

  4. 35Cl NQR study of incommensurate state in thiourea-hexachloroethane inclusion compound

    NASA Astrophysics Data System (ADS)

    Panich, A. M.; Semenov, A. R.; Chekhova, G. N.; Krieger, Ju. H.; Goren, S. D.

    1999-04-01

    A study of the incommensurate phase of the channel thiourea-hexachloroethane inclusion compound by means of 35Cl NQR, in the temperature range from 68 to 88 K, is presented. Hahn echo measurements indicate the slow diffusion-like motion of the modulation wave. This motion is obtained close to the transition temperature Ti˜90 K. At higher temperatures, the NQR spectrum is not observed. We attribute this fact to the reorientational mobility of C 2Cl 6 molecules in the host sublattice, probably accompanied by an order-disorder phase transition.

  5. 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.

  6. 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.

  7. NQR study of neutral-ionic phase transition and quantum paraelectric state in organic charge-transfer complexes

    NASA Astrophysics Data System (ADS)

    Iwase, Fumitatsu; Miyagawa, Kazuya; Kanoda, Kazushi; Horiuchi, Sachio; Tokura, Yoshinori

    2008-12-01

    NQR measurements were performed for the charge-transfer complexes DMTTF-QBr nCl n-4 under ambient and hydrostatic pressures in order to understand the neutral-ionic phase transition and the quantum critical behavior. The 35Cl NQR spectrum of DMTTF-QCl 4 showed a splitting and a shift below Tc, indicating the occurrence of dimerization and charge transfer. The spin-lattice relaxation rate 1/ T1 showed a peak anomaly around Tc, reflecting the critical slowing down. The quantum paraelectric states in DMTTF-2,6-QBr 2Cl 2 and pressured DMTTF-QBr 4 were studied by the 79Br NQR. We found the microscopic evidence for the evolution of the critical fluctuations at low temperatures in the temperature dependence of spin-lattice relaxation rate.

  8. Ru-NQR studies on filled skutterudite compounds RRu4P12 (R=La,Nd,Sm)

    NASA Astrophysics Data System (ADS)

    Masaki, S.; Mito, T.; Takemura, M.; Wada, S.; Harima, H.; Kikuchi, D.; Sato, H.; Sugawara, H.; Takeda, N.; Zheng, G.-q.

    2008-04-01

    We report nuclear quadrupole resonance (NQR) studies on Ru-sites of filled skutterudite compounds RRu4P12 (R=La,Nd,Sm) in zero magnetic field. For NdRu4P12, the Ru101-NQR signal disappears below TC=1.6 K, which is indicative of the transformation into the ferromagnetically ordered ground state. For SmRu4P12, a single Ru101-NQR line splits into two lines below the metal-insulator transition temperature TMI=16.5 K with the intensity ratio of 3:1. This result gives evidence that there are two inequivalent Ru-sites with different electric field gradient. The intensity ratio leads to a conclusion that the symmetry is lowered below TMI from a cubic Im3bar space group to a trigonal R3bar one.

  9. Cu NQR study of charge localization in HgBa2CuO4+? with different oxygen content

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Antipov, E. V.; Hoffmann, W.; Lders, K.

    1996-02-01

    Variation of the oxygen content ? in HgBa2CuO4+?(1201) provides a good opportunity to study the influence of oxygen doping on nuclear quadrupole interactions (NQI) and charge localization in different regions of (Tc-?) phase diagram. We performed63,65Cu NQR of series HgBa2CuO4+? samples with different oxygen content ?.

  10. 93Nb- and 27Al-NMR/NQR studies of the praseodymium based PrNb2Al20

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-03-01

    We report a study of 93Nb- and 27Al-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) in a praseodymium based compound PrNb2Al20. The observed NMR line at around 3 T and 30 K shows a superposition of typical powder patterns of one Nb signal and at least two Al signals. 93Nb-NMR line could be reproduced by using the previously reported NQR frequency ?Q ? 1.8MHz and asymmetry parameter ? ? 0 [Kubo T et al 2014 JPS Conf. Proc. 3 012031]. From 27Al-NMR/NQR, NQR parameters are obtained to be ?Q,A ? 1.53 MHz, and ?A ? 0.20 for the site A, and ?Q,B ? 2.28 MHz, and ?B ? 0.17 for the site B. By comparing this result with the previous 27Al-NMR study of PrT2Al20 (T = Ti, V) [Tokunaga Y et al 2013 Phys. Rev. B 88 085124], these two Al site are assigned to the two of three crystallographycally inequivalent Al sites.

  11. 35Cl NQR Study of Thermoactivated Motions of Nitro Groups in Picryl Chloride

    NASA Astrophysics Data System (ADS)

    Kyuntsel, Igor A.

    1996-06-01

    The temperature dependences of the 35Cl NQR frequency (ν), spin-lattice relaxation time (T1), and spin-spin relaxation time (T2) have been studied in 2,4,6-trinitrochlorobenzene (picryl chloride) from 77 K up to the melting point (354 K). The T1(T) curve exhibits a pronounced composite mimimum near 300 K which gives evidence for the reorientations of the two ortho-NO2 groups around their two-fold symmetry axes with the activation energies of 27.4 kJ mol - 1 and 31.2 kJ mol - 1. These values can be related to the ortho-NO2 groups having the twist angles of 33° and 81°, respectively (the crystal structure of picryl chloride is known). The T2(T) dependence exhibits interesting features, too: a deep minimum about 140 K and a new rapid decrease above 270 K.

  12. 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.

  13. 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

  14. 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, ? and asymmetry parameter, ?. 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 (?, ?) 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

  15. NQR study of local structures and cooling rate dependent superconductivity in La sub 2 CuO sub 4+. delta

    SciTech Connect

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

    1992-01-01

    Structural properties of oxygen-annealed polycrystals of La{sub 2}CuO{sub 4 + {delta}} ({delta}{approximately}0.03) have been studied using {sup 139}La NQR spectroscopy. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range at about 195K. Preliminary analysis of the {sup 139}La NQR spectra suggest that the oxygen-rich phase-separated region is composed of two structurally distinct phases, both of which are metallic and super-conducting. One phase has a structure closely related to the stoichiometric oxygen-poor compound. The second shows a considerable amount of apical oxygen disorder, a large shift in NQR frequency {nu}{sub Q}, and a volume fraction which increases with cooling rate. The formation of the second phase below {minus}200K is indicative of the freezing Of CuO{sub 6} octahedral tilting. Abrupt shifts in {nu}{sub Q} above {Tc} were also observed for both phases, suggestive of a local structural anomaly or charge transfer to the Cu-O plane.

  16. 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)

    Latosi?ska, J. N.; Latosi?ska, M.; Seliger, J.; agar, 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.

  17. 75As-NQR study of the hybridization gap semiconductor CeOs4As12

    NASA Astrophysics Data System (ADS)

    Yogi, M.; Higa, N.; Niki, H.; Kawata, T.; Sekine, C.

    2016-02-01

    We performed an 75As nuclear quadrupole resonance (NQR) measurement on CeOs4As12. The 75As-NQR spectrum shape demonstrates that the Ce-site filling fraction of our high-pressure synthesized sample is close to unity. A presence of the c — f hybridization gap is confirmed from the temperature dependence of the nuclear spin-lattice relaxation rate 1/T1. An increase of 1/T1 below ∼3 K indicates a development of the spin fluctuations. The 1/T1 for CeOs4As12 shows similar behavior as that for CeOs4Sb12 with different magnitude of the c — f hybridization gap. An absence of phase transition in CeOs4As12 may be caused by the increase of the c — f hybridization, which increases the gap magnitude and reduces the residual density of state inside the gap.

  18. Sodium and potassium salts of dichloroisocyanuric acid and their hydrates as antimicrobials agents studied by 35Cl-NQR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Walczak, A.; Brycki, B.; Kaczmarek, M.; Poleshchuk, O. Kh.; Ostafin, M.; Nogaj, B.

    2006-06-01

    The electronic structure of dichloroisocyanuric acid derivatives was analysed by 35Cl-NQR spectroscopy and DFT calculations. Here we concentrate our attention on three different factors: type of metallic substituent (sodium and potassium), temperature of the sample (liquid nitrogen and room) and degree of hydration (an amount of water molecules attached to analysed compounds). In particular, all the variations in 35Cl-NQR frequencies upon hydration of salts containing sodium and potassium ions are explained as a consequence of H-bonds formation and accompanied effects of charge redistribution. Our studies can be useful in searching for the derivatives of dichloroisocyanuric acid revealing higher antimicrobial activity.

  19. 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 should not be any obstacle, which is relevant from the pharmaceutical industry point of view. PMID:26826282

  20. 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 BayerKushidaBrown 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.

  1. 105Pd NMR/NQR studies in UPd 2Al 3

    NASA Astrophysics Data System (ADS)

    Matsuda, K.; Kohori, Y.; Kohara, T.

    1999-01-01

    105Pd NMR and NQR measurements have been performed both in the normal and in the superconducting states for UPd 2Al 3. In the antiferromagnetically (AF) ordered state, the small internal field of about 3 kOe (at 4.2 K), which is perpendicular to the c-axis, appears below 14.5 K and does not decrease in the superconducting state. The nuclear spin-lattice relaxation rate, 1/ T1, in UPd 2Al 3 is nearly temperature, T, independent in the paramagnetic state up to 60 K, successively diverges at Nel temperature associated with the critical slowing down of U magnetic moments, and then decreases markedly in the AF ordered state. In the superconducting state, 1/ T1 decreases in proportion to T3 down to 0.4 K with no coherence peak just below TC, which indicates the occurrence of anisotropic superconductivity having line nodes in the superconducting energy gap.

  2. 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.

  3. 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.; ?nuki, 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).

  4. Intensity of NQR lines for integer spins

    NASA Astrophysics Data System (ADS)

    Anferov, V. P.; Beloglazov, G. S.; Grechishkin, V. S.

    1986-12-01

    Because of the publication of contradictory information demonstrating an incorrect approach to the modeling of NQR-NMR frequency-intensity spectra of integral-spin isotopes (for example, boron-10), we study the NQR-NMR double resonance with level crossing (DRLC) in10B-1H,11B-1H,59K-1H and23Na-1H in crystal hydrates of sodium tetraborate (Na2B4O710H2O) and potassium tetraborate (K2B4O74H2O) and the results of the measurements are compared with theoretical calculations. The fact that for a system including three elements-quadrupole (NQR), Zeeman (NMR), and dipole-dipole, which establishes the interaction of the first two- the intensities of the lines in double resonance spectra are determined both by the equations of balance of the populations of the levels of the quadrupole and Zeeman reservoirs and by the probabilities of transitions within each reservoir is taken into account in the calculations. The distortion of the energy levels of the NQR subsystem by the magnetic field in the process of level crossing with the NMR subsystem is taken into account.

  5. 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.

  6. 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

    Latosi?ska, Jolanta Natalia; Latosi?ska, 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) , b = 8.3158(3) , c = 8.6892(3) ; ? = 81.212(3), ? = 73.799(3), ? = 67.599(3). Its molecules form symmetric dimers linked by two short and linear intermolecular hydrogen bonds O-HO (O-HO = 2.648 and ?OHO = 171.5), which are further linked by weaker and longer intermolecular hydrogen bonds N-HO (N-HO = 2.965 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 displacements at both chlorine sites is derived from the (35)Cl-NQR temperature dependence. The frequencies of torsional vibrations higher for the para site than the ortho site are in good agreement with those obtained from thermal parameters obtained from X-ray studies. The mean square angle displacements are in good agreement with those estimated from X-ray data with the use of the TLS model. The detailed DFT/QTAIM analysis suggests that the interplay between different hydrogen bonds in adjacent molecules forming dimers is responsible for the differences in flexibility of the carboxyl and sulphonamide substituents as well as both C-Cl(1) and C-Cl(2) bonds. Three ultralow wavenumber modes of internal vibrations in Raman and IR spectra obtained at the B3LYP/6-311++G(d,p) level close to those obtained within the TLS model suggest that internal and external modes of vibrations are not well separated. PMID:23020838

  7. Chlorine-35 NQR and 1H NMR study of guest structure and dynamics in the thiourea-hexachloroethane inclusion compound

    NASA Astrophysics Data System (ADS)

    Panich, A. M.; Krieger, Ju H.; Semenov, A. R.; Goren, S. D.; Chekhova, G. N.

    2000-07-01

    Atom-atomic potential calculation of the channel non-stoichiometric thiourea-hexachloroethane inclusion compound shows that the structure of the guest sublattice comprises two types of finite molecular chain, having different structure and separated by domain walls. In the present paper we present results of 35Cl NQR and 1H NMR measurements of thiourea-hexachloroethane, [2.95(NH2)2CS]C2Cl6, in the temperature range from 7.5 to 90 K, which confirm this model and show the existence of such a state at least below 60 K. Two resonances in the NQR spectra were assigned to the two nearly commensurate regions, while the third resonance, showing an anomalous behaviour, was attributed to the guest molecules in the domain wall. The observed structure results from the different periodicity of the guest and host substructures and shows a difference from conventional continuum models of the incommensurate state. Propagation motion of the domain wall over the channel is discussed.

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

    SciTech Connect

    Murty, A.N.

    1992-01-01

    We have investigated a series of Cu/Co catalysts supported on Titanium Dioxide. This study has sought to examine and compare the nature and effect of the supports Chromia and Titania (Cr[sub 2]O[sub 3], and TiO[sub 2]) on the magnetic character of the Cu-Co-Cr and Cu-Co-TiO[sub 2] catalysts. The magnetization results for Cu/Co, Cu/Co/Cr, Cu/Co/TiO[sub 2] system are presented along with the magnetization data for the unsupported Cu/Co catalysts and data for supported catalysts. Pure cobalt metal has a magnetic moment of 161 emu/g. The measured emu values and the corresponding reduction percentages are given for the various catalysts investigated. The vibration sample magnetometer determines S[sub s], the saturation magnetization, emu per gram of the composite sample. The magnetization values reported are emu per gram of cobalt in the composite. As such the data normally reflects the proportion of cobalt metal that is reduced to metallic form. However, if electronic exchanges occur between cobalt and other elements in the system, the magnetic moment itself differs from the assumed value of 161 emu/g Co then the emu value observed will be the resultant due to the electronic charge density modifications in Co as well as reduction to metallic state. Our earlier NMR studies reveal such electronic structural modifications occur for Cobalt in Cu-Co and Co-TiO[sub 2] systems. The magnetization data in column 3 for Cu-Co-TiO[sub 2] systems unambiguously shows such electron exchanges do occur between cobalt and titania.

  9. Two-dimensional exchange 35Cl NQR spectroscopy of hexachloroethane

    NASA Astrophysics Data System (ADS)

    Maćkowiak, Mariusz; Sinyavsky, Nicolay; Bluemich, Bernhard

    2005-05-01

    Two-dimensional exchange 35Cl NQR spectroscopy for studies of the CCl 3-group reorientation processes in hexachloroethane has been applied. It has been demonstrated that 2D NQR exchange spectroscopy is appropriate for quantitative studies of exchange processes in molecular crystals containing quadrupole nuclei. The method is of particular value for the detection of exchange networks in systems with many sites. Thus, detailed information on the exchange pathways within a network of structural isomers in hexachloroethane can be deduced and a proper assignment of the NQR lines can be made. Temperature dependence of the exchange rate was studied. The mixing dynamics by exchange and the expected cross-peak intensities have been derived. The very good agreement of the experimental results with theoretical predictions confirms the validity of the motion model.

  10. Experimental study of the structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se by means of NQR and EPR spectroscopy

    NASA Astrophysics Data System (ADS)

    Bolebrukh, Olga; Sinyavsky, Nikolay; Korneva, Irina; Dobosz, Bernadeta; Ostafin, Michal; Nogaj, Boleslaw; Krzyminiewski, Ryszard

    2013-12-01

    The structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se has been studied by means of both NQR (nuclear quadrupole resonance) and EPR (electron paramagnetic resonance) spectroscopy. It is investigated that in the glasses of both systems the value of the electric field gradient at the resonating nuclei grows with increasing concentration of the clusters As2Se3 and Sb2Se3, thereby increasing the NQR resonance frequencies. It appears that for the Ge-As-Se system the structural transition from a two-dimensional to three-dimensional structure occurs at average coordination number bar r = 2.45. The EPR spectral parameters of glasses depend on the composition, the average coordination number and the temperature, and these are discussed. The effect of "ageing" for CGS (chalcogenide glassy semiconductors) of As-Sb-Se system due to partial crystallization of the sample is observed from the EPR spectra.

  11. 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.

  12. 139La NQR and NMR studies of the structural phase transitions in La 1.8- xEu 0.2Sr xCuO 4

    NASA Astrophysics Data System (ADS)

    Suh, B. J.; Hammel, P. C.

    139La NQR and NMR relaxation measurements in the title compound have been used to investigate the dynamical properties of the structural phase transitions (SPT): HTT ? LTO and LTO ? LTT of lathanum cuprate. We present the data for thermodynamic fluctuations of critical modes in the vicinity of the SPT's which clearly reveal the character of each SPT and its dependence on doped hole concentration.

  13. 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.

  14. A study of transition-metal organometallic complexes combining 35Cl solid-state NMR spectroscopy and 35Cl?NQR spectroscopy and first-principles DFT calculations.

    PubMed

    Johnston, Karen E; O'Keefe, Christopher A; Gauvin, Rgis M; Trbosc, Julien; Delevoye, Laurent; Amoureux, Jean-Paul; Popoff, Nicolas; Taoufik, Mostafa; Oudatchin, Konstantin; Schurko, Robert W

    2013-09-01

    A series of transition-metal organometallic complexes with commonly occurring metal-chlorine bonding motifs were characterized using (35)Cl solid-state NMR (SSNMR) spectroscopy, (35)Cl nuclear quadrupole resonance (NQR) spectroscopy, and first-principles density functional theory (DFT) calculations of NMR interaction tensors. Static (35)Cl ultra-wideline NMR spectra were acquired in a piecewise manner at standard (9.4?T) and high (21.1?T) magnetic field strengths using the WURST-QCPMG pulse sequence. The (35)Cl electric field gradient (EFG) and chemical shielding (CS) tensor parameters were readily extracted from analytical simulations of the spectra; in particular, the quadrupolar parameters are shown to be very sensitive to structural differences, and can easily differentiate between chlorine atoms in bridging and terminal bonding environments. (35)Cl?NQR spectra were acquired for many of the complexes, which aided in resolving structurally similar, yet crystallographically distinct and magnetically inequivalent chlorine sites, and with the interpretation and assignment of (35)Cl?SSNMR spectra. (35)Cl?EFG tensors obtained from first-principles DFT calculations are consistently in good agreement with experiment, highlighting the importance of using a combined approach of theoretical and experimental methods for structural characterization. Finally, a preliminary example of a (35)Cl?SSNMR spectrum of a transition-metal species (TiCl4) diluted and supported on non-porous silica is presented. The combination of (35)Cl?SSNMR and (35)Cl?NQR spectroscopy and DFT calculations is shown to be a promising and simple methodology for the characterization of all manner of chlorine-containing transition-metal complexes, in pure, impure bulk and supported forms. PMID:23907813

  15. NMR and NQR study of the electronic and structural properties of Al-Cu-Fe and Al-Cu-Ru quasicrystals

    SciTech Connect

    Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I. )

    1994-12-01

    [sup 27]Al and [sup 63,65]Cu NMR is reported for powdered stable Al-Cu-Fe and Al-Cu-Ru icosahedral quasicrystals and crystalline approximants, and for an Al-Pd-Mn single-grain quasicrystal. [sup 27]Al NQR spectra at 4.2 K were observed in Al-Cu-Fe and Al-Cu-Ru samples. From quadrupole-perturbed NMR spectra at different magnetic fields, and from 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 Al-Cu-Fe approximant successfully explained the observed NQR spectra. The average local gradient is largely determined by the [ital p]-electron wave function at the Al site, while the width of the distribution is due to EFG lattice contribution. Comparison of [sup 63]Cu and [sup 27]Al NMR shows the EFG distribution at the two sites is similar, but the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more [ital s]-type wave function of the conduction electrons. Overall spread of EFG values is well reproduced by calculation based on the approximant. However, the experimental spectra indicate a much larger number of nonequivalent sites when compared with the simulated NQR spectra based on the 1/1 approximant. The short-range, local chemical order is well represented by the approximant, but differences in coordination must be included at intermediate range in the quasicrystal. Measured [sup 27]Al Knight shift, magnetic susceptibility, and nuclear spin-lattice relaxation time as a function of temperature indicate reduced density of states at the Fermi level by a factor of 7 or 8 from the value in Al metal, consistent with the notion of a pseudogap for these quasicrystals. No differences in measured parameters were detected as a function of composition of the quasicrystalline alloys.

  16. 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

  17. A Pulsed Spectrometer Designed for Feedback NQR

    NASA Astrophysics Data System (ADS)

    Schiano, J. L.; Ginsberg, M. D.

    2000-02-01

    A pulsed NQR spectrometer specifically designed to facilitate real-time tuning of pulse sequence parameters is described. A modular approach based on the interconnection of several rack-mounted blocks provides easy access to all spectrometer signals and simplifies the task of modifying the spectrometer design. We also present experimental data that demonstrates the ability of the spectrometer to increase the signal to noise ratio of NQR measurements by automatically adjusting the pulse width in the strong off-resonant comb pulse sequence.

  18. 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.

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

    PubMed

    Begu, Samo; Jazbinek, 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

  20. Jun2006 Years of Nmr/nqr Experiments in Solid Electrolytes

    NASA Astrophysics Data System (ADS)

    Brinkmann, Detlef

    2006-06-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) experiments in solid electrolytes started around 1975 when a new interest arose in solids with high ionic conductivity. The emphasis of this revue is on experiments rather than theoretical issues. We will present typical NMR/NQR studies which demonstrate the power of these techniques to elucidate dynamic and static behavior of these solids at a microscopic level. Because of the overwhelming wealth of results accumulated in the last 30 years, we will be limited to some characteristic examples.

  1. 14 N NQR spectrum of sildenafil citrate

    NASA Astrophysics Data System (ADS)

    Stephenson, David; Singh, Nadia

    2015-04-01

    The 14N nuclear quadrupole resonance (NQR) spectrum of sildenafil citrate tablets has been recorded allowing the quadrupole coupling constants and asymmetry parameters of all six unique nitrogen atoms in its structure to be determined. A density function calculation gives results that are largely in agreement with the experimental values.

  2. 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 ?m?=?1 and ?m?=?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

  3. PEANUT experiment in NQR spectroscopy for I=3/2.

    PubMed

    Sinyavsky, Nikolay; Dolinenkov, Philip; Ma?kowiak, Mariusz

    2012-01-01

    The experiment with phase inversion and phase-inverted echo-amplitude detected nutation (PEANUT) was introduced in the nuclear quadrupole resonance (NQR). Formulas were obtained describing the NQR (I=3/2) experiment. Exemplary experiments are provided confirming the predicted particularities of the PEANUT spectra in NQR Cl-35. It is proposed to apply the method for the purpose of determination the asymmetry parameter of the electric field gradient (EFG) tensor in powders with the help of the analysis of PEANUT interferograms. Application of two-dimensional PEANUT experiments, in which the nutation frequencies correlate with the resonance NQR frequencies, can substantially simplify the interpretation of complex spectra. PMID:22365993

  4. An innovative method for the non-destructive identification of photodegradation products in solid state: 1H-14N NMR-NQR and DFT/QTAIM study of photodegradation of nifedipine (anti-hypertensive) to nitrosonifedipine (potential anti-oxidative).

    PubMed

    Latosi?ska, J N; Latosi?ska, M; Seliger, J; Zagar, V

    2012-08-30

    Stability of the antihypertensive drug nifedipine (NIF) has been studied experimentally in solid state by (1)H-(14)N NMR-NQR double resonance (NQDR) and theoretically by the Density Functional Theory (DFT). Photodegradation of NIF to its metabolite in vivo nitrosonifedipine, NO-NIF (antioxidative agent) upon long term daylight exposure was detected and the changes in the molecular structure of NIF were analysed. The photoconversion of NIF to NO-NIF in solid was found to be accompanied with the electron density redistribution at nitrogen sites (NH to N and NO(2) to NO) and proved to be successfully detected with identification of photoproducts by (1)H-(14)N NQDR and DFT methods. The increase in the e(2)qQ/h and ? describing EFG tendency towards non-spherical symmetry was significantly greater upon the reduction of NO(2) site than upon hydrogen abstraction from NH site. The level of sensitivity of detection of the photodegradation product was about 1% of the original sample. The Quantum Theory of Atoms in Molecules (QTAIM) analysis has been found useful in predicting photoreactive sites in the molecules and finding the explanation of differences in reactivity between parent NIF and its photoproduct NO-NIF. Using NIF as a model, this study demonstrates the suitability of NQDR supported by DFT for non-destructive determination of the photodegradation products in solid state. PMID:22609436

  5. Absence of Magnetic Dipolar Phase Transition and Evolution of Low-Energy Excitations in PrNb2Al20 with Crystal Electric Field ?3 Ground State: Evidence from 93Nb-NQR Studies

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-07-01

    We report measurements of bulk magnetic susceptibility and 93Nb nuclear quadrupole resonance (NQR) in the Pr-based caged compound PrNb2Al20. By analyzing the magnetic susceptibility and magnetization, the crystal electric field (CEF) level scheme of PrNb2Al20 is determined to be ?3(0 K)-?4(21.32 K)-?5(43.98 K)-?1(51.16 K) within the framework of the localized 4f electron picture. The 93Nb-NQR spectra exhibit neither spectral broadening nor spectral shift upon cooling down to 75 mK. The 93Nb-NQR spin-lattice relaxation rate 1/T1 at 5 K depends on the frequency and remains almost constant below 5 K. The frequency dependence of 1/T1 is attributed to the magnetic fluctuation due to the hyperfine-enhanced 141Pr nuclear moment inherent in the nonmagnetic ?3 CEF ground state. The present NQR results provide evidence that no symmetry-breaking magnetic dipole order occurs down to 75 mK. Also, considering an invariant form of the quadrupole and octupole couplings between a 93Nb nucleus and Pr 4f electrons, Pr 4f quadrupoles and an octupole can couple with a 93Nb nuclear quadrupole moment and nuclear spin, respectively. Together with the results of bulk measurements, the present NQR results suggest that the possibility of a static quadrupole or octupole ordering can be excluded down to 100 mK. At low temperatures below 500 mK, however, the nuclear spin-echo decay rate gradually increases and the decay curve changes from Gaussian decay to Lorentzian decay, suggesting the evolution of a low-energy excitation.

  6. Pressure Dependence of the Chlorine NQR in Chloro Pyridines

    NASA Astrophysics Data System (ADS)

    Ramesh, K. P.; Ramakrishna, J.; Suresh, K. S.; Rao, C. Raghavendra

    2000-02-01

    The 35CI NQR frequency (?Q) and spin lattice relaxation time (T1 ) in 2,6-dichloropyridine, 2 amino 3,5-dichloropyridine and 6 chloro 2-pyridinol have been measured as a function of pressure up to 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three compounds show a non linear variation of the NQR frequency with pressure which can be described by a 2nd order polynomial in pressure. The rate of change of the NQR frequency with pressure is positive and decreases with increasing pressure. The spin lattice relaxation time T1, in all the three compounds shows a small increase with pressure, indicating that the relaxation is mainly due to the torsional motions.

  7. 35Cl NQR Spectra of several 2,2-bis- p-chlorophenyl chloroethane derivatives

    NASA Astrophysics Data System (ADS)

    Nogaj, B.; Pietrzak, J.; Wielopolska, E.; Schroeder, G.; Jarczewski, A.

    Measurement of NQR line frequency at 77 K have been performed for the following compounds: 1-chloro-2,2-bis-(p-chlorophenyl) ethylene (DDMU), 1,1-dichloro-2,2-bis-(p-chlorophenyl) ethylene (DDE), 1,1-dichloro-2,2-bis-(p-chlorophenyl) ethane (ODD), 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT). An attempt to assign spectrum lines to particular Cl nuclei in a molecule has been made. Molecular and crystallographic inequivalences occurring in these compounds have been considered. Comparison of the NQR and crystallographic data revealed the influence of phenyl rings conformation on electric charge distribution in the studied molecules.

  8. 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.

  9. 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 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

  10. Low-Frequency NMR and Nqr with a DC SQUID Amplifier

    NASA Astrophysics Data System (ADS)

    Fan, Nong-Qiang

    A sensitive Fourier-transform spectrometer based on a dc SQUID (Superconducting QUantum Interference Device) has been developed for the direct detection of nuclear magnetic resonance (NMR) in zero applied magnetic field and pure nuclear quadrupole resonance (NQR) at low frequencies. The motivation to detect zero field NMR and NQR is to provide a new high resolution spectroscopy technique at frequencies below 200 kHz to study ultra-weak interactions in chemicals and materials. By comparing the sensitivity of a SQUID amplifier with that of a conventional semiconductor amplifier, it is shown that a SQUID amplifier is essential for the direct detection of low frequency resonant signals. The spectrometer has a frequency response extending from about 10 to 200 kHz, and a recovery time (after the magnetic pulse is removed) of about 50 mus. The spectrometer is used to detect NMR spectra from Pt and Cu metal powders in a magnetic field of 6 mtesla, and NQR spectra from ^2D in a tunneling methyl group and ^{14}N in rm NH_4ClO_4. Finally, the zero field NMR spectrum from a quantum tunneling methyl group is calculated.

  11. Mutual effect of ligands in nitrido and nitroso complexes of osmium and ruthenium from NQR data

    SciTech Connect

    Kravchenko. E.A.; Burtsev, M.Yu.; Sinitsyn, M.N.; Svetlov, A.A.; Kokunov, Ya.V.; Buslaev, A.

    1987-11-01

    The purpose of this investigation was to study by NQR the spectral results of the mutual ligand effect in complex compounds having various types of short bonds. The authors obtained the /sup 35/Cl, /sup 81/Br, and /sup 127/I NQR spectra of a large number of halogen complexes of osmium and ruthenium having short Os=N and M in equilibrium NO bonds of the following types: R(OsNHal/sub 4/) (R = (Ph/sub 4/P)/sup +/, (Bu/sub 4/N)/sup +/; Hal = Cl/sup -/, Br/sup -/, I/sup -/), K/sub 2/(OsNCl/sub 5/), Rb/sub 2/(OsNBr/sub 5/), (NH/sub 4/)/sub 2/(OsNBr/sub 5/), K(OsNHal/sub 4/L) (Hal = Cl/sup -/, Br/sup -/; L = H/sub 2/O, CH/sub 3/CN), K/sub 2/(MNOHal/sub 5/) (M = Os, Ru; Hal = Cl/sup -/, Br/sup -/, I/sup -/). The experimental NQR values measured are connected by the Townes and Dailey theory with the chemical bond characteristics i, sigma, ..pi.., the degree of the ionic, the sigma-covalent, and the ..pi..-covalent natures respectively ( i + sigma + ..pi.. = 1).

  12. Numerical simulation of NQR/NMR: Applications in quantum computing.

    PubMed

    Possa, Denimar; Gaudio, Anderson C; Freitas, Jair C C

    2011-04-01

    A numerical simulation program able to simulate nuclear quadrupole resonance (NQR) as well as nuclear magnetic resonance (NMR) experiments is presented, written using the Mathematica package, aiming especially applications in quantum computing. The program makes use of the interaction picture to compute the effect of the relevant nuclear spin interactions, without any assumption about the relative size of each interaction. This makes the program flexible and versatile, being useful in a wide range of experimental situations, going from NQR (at zero or under small applied magnetic field) to high-field NMR experiments. Some conditions specifically required for quantum computing applications are implemented in the program, such as the possibility of use of elliptically polarized radiofrequency and the inclusion of first- and second-order terms in the average Hamiltonian expansion. A number of examples dealing with simple NQR and quadrupole-perturbed NMR experiments are presented, along with the proposal of experiments to create quantum pseudopure states and logic gates using NQR. The program and the various application examples are freely available through the link http://www.profanderson.net/files/nmr_nqr.php. PMID:21324720

  13. (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

  14. Two-dimensional NQR using ultra-broadband electronics

    NASA Astrophysics Data System (ADS)

    Mandal, S.; Song, Y.-Q.

    2014-03-01

    We have recently developed an ultra-broadband instrument that can effectively excite and detect NMR and NQR signals over a wide frequency range. Our current system operates between 100 kHz and 3.2 MHz using an un-tuned sample coil. The major benefits of this instrument compared to conventional NQR/NMR systems include increased robustness, ease of use (in particular for multi-frequency experiments), and elimination of the need for tuning adjustments in the hardware. Here we describe its use for performing two-dimensional (2D) scans, which allow improved interpretation of complex NQR spectra by detecting the connected resonances. Our method relies on population transfers between the three energy levels of spin-1 nuclei (such as 14N) by using multi-frequency excitation and a single RF coil. Experimental results on pure samples and mixtures are also presented.

  15. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, September 15--December 15, 1992

    SciTech Connect

    Murty, A.N.

    1992-12-31

    We have investigated a series of Cu/Co catalysts supported on Titanium Dioxide. This study has sought to examine and compare the nature and effect of the supports Chromia and Titania (Cr{sub 2}O{sub 3}, and TiO{sub 2}) on the magnetic character of the Cu-Co-Cr and Cu-Co-TiO{sub 2} catalysts. The magnetization results for Cu/Co, Cu/Co/Cr, Cu/Co/TiO{sub 2} system are presented along with the magnetization data for the unsupported Cu/Co catalysts and data for supported catalysts. Pure cobalt metal has a magnetic moment of 161 emu/g. The measured emu values and the corresponding reduction percentages are given for the various catalysts investigated. The vibration sample magnetometer determines S{sub s}, the saturation magnetization, emu per gram of the composite sample. The magnetization values reported are emu per gram of cobalt in the composite. As such the data normally reflects the proportion of cobalt metal that is reduced to metallic form. However, if electronic exchanges occur between cobalt and other elements in the system, the magnetic moment itself differs from the assumed value of 161 emu/g Co then the emu value observed will be the resultant due to the electronic charge density modifications in Co as well as reduction to metallic state. Our earlier NMR studies reveal such electronic structural modifications occur for Cobalt in Cu-Co and Co-TiO{sub 2} systems. The magnetization data in column 3 for Cu-Co-TiO{sub 2} systems unambiguously shows such electron exchanges do occur between cobalt and titania.

  16. 35CI NQR and Structural Studies of N-(2,6-Dichlorophenyl)-Amides, 2,6-Cl2C6H3-NHCO-R (R = H or CH3-y Xy and X = CH3 or CI; y = 0,1, 2 or 3)

    NASA Astrophysics Data System (ADS)

    Gowda, B. Thimme; Paulus, Helmut; Fuess, Hartmut

    2000-10-01

    The effect of side chain substitution on the 35CI NQR and crystal structure of amides of the type N-(2,6-dichlorophenyl)-amides, 2,6-Cl2C6H3-NHCO-R (R = H or CH3_yXy where X = CH3 or CI and y = 0, 1, 2 or 3), has been studied by measuring the 35C1 NQR spectra and determining the crystal structures of the compounds N-(2,6-dichlorophenyl)-formamide, 2,6-Cl2C6H3- NHCO-H (DCPFA); N-(2,6-dichlorophenyl)-2-methylacetamide(propionamide), 2,6-Cl2C6H3- NHCO-CH2CH3 (DCPMA); N-(2,6-dichlorophenyl)-2,2-dimethylacetamide(isobutyramide), 2,6- Cl2C6H3-NHCO-CH(CH3 ) 2 (DCPDMA) and N-(2,6-dichlorophenyl)-2,2,2-trimethylacetamide (neopentylamide), 2,6-Cl2C6H3-NHCO-C(CH3)3 (DCPTMA), and by analysing the present data along with the 35CI NQR spectra and / or crystal structures of the compounds, 2,6-dichloroaniline, 2,6-Cl2C6H3-NH2 (DCA), N-(2,6-dichlorophenyl)-acetamide, 2,6-Cl2C6H3--NHCO-CH3 (DCPA), N-(2,6-dichlorophenyl)-2-chloroacetamide, 2,6-Cl2C6H3-NHCO-CH2Cl (DCPCA), N- (2,6-dichlorophenyl)-2,2-dichloroacetamide, 2,6-Cl2C6H3-NHCO-CHCl2 (DCPDCA) and N- (2,6-dichlorophenyl)-2,2,2-trichloroacetamide, 2,6-Cl2C6H3-NHCO-CCl3 (DCPTCA). The crystal type, space group, formula units and lattice constants in A of the new structures are;DCPFA: orthorhombic, Pbca, Z = 8, a = 8.593(3), b = 12.728(4), c = 14.376(4); DCPMA: orthorhombic, P212121, Z = 4, a = 4.774(2), b = 10.961(5), c = 19.562(8); DCPDMA: monoclinic, P21/c, Z = 4, a = 9.901(4), b = 13.785(5), c = 9.060(3), = 103.58(2) and DCPTMA: monoclinic, P21/n, Z = 8, a = 16.047(5), b = 9.882(3), c = 16.270(5) = 102.12(1). The compound, DCPTMA shows two molecules in its asymmetric unit. This is in agreement with the multiple lines observed in the 35CI NQR spectra of the compound. The conversion of DCA (monoclinic) into it's various acid amides DCPFA, DCPA, DCPMA, DCPDMA, DCPTMA, DCPCA and DCPTCA affects it's crystal symmetry. The replacement of the side chain CH3 in DCPA by the H atom or substitution of either a CH3 group or a CI atom for one of the H atoms in the side chain CH3 or replacement of the two ring CI atoms by the H atoms changes it's crystal symmetry from monoclinic to orthorhombic, while the substitution of 2 or all the 3 H atoms in the CH3 group of DCPA by 2 or 3 CH3 groups or CI atoms restores it's crystal symmetry back to the monoclinic type. The bond lengths and bond angles are normal except for some deviations.

  17. 14N NQR and relaxation in ammonium nitrate

    NASA Astrophysics Data System (ADS)

    Stephenson, David

    2015-04-01

    The complete 14N nuclear quadrupole resonance (NQR) spectrum of ammonium nitrate is presented recorded using two double resonance techniques - double contact cross relaxation and zero field NQR. The spectra gave the quadrupole coupling constant (Qcc) and asymmetry parameter ( ?) values for the nitro of 611 kHz, 0.229 and that for the ammonium nitrogen of 242 kHz, 0.835. The three relaxation transition probabilities have been determined for both the nitro and ammonium nitrogen atoms. The bi-exponential relaxation times (T 1) were measured at 295 K. The values for nitro are 16.9 s and 10.5 s and that of the ammonium are 23.0 s and 16.4 s.

  18. 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, and therefore might have a significant heteronuclear dipolar coupling component. To incorporate this, a second model is developed composed of two different nuclear species, one spin 1 the other spin 1/2, although the work can be extended to additional spin species. This model reveals that heteronuclear dipolar coupling for this system behaves just like EFG broadening under spin locking, and that the strong homonuclear response is still observable. The experimental results closely match theoretical predictions, and the conclusions greatly expand the number of target substances that are suitable for this measurement technique of homonuclear dipolar coupling. The combined results explain why certain pulse sequences perform better than others for substance detection: it is because of the relative strengths of the line broadening mechanisms. Therefore the ability to measure homonuclear dipolar coupling's contribution to the linewidth is useful not only for material characterization, but also for substance detection. By explaining the conditions that reveal homonuclear coupling, we make it possible to measure the relative broadening strengths, increasing the efficiency of NQR in these roles.

  19. Optimization of NQR Pulse Parameters using Feedback Control

    NASA Astrophysics Data System (ADS)

    Schiano, J. L.; Blauch, A. J.; Ginsberg, M. D.

    2000-02-01

    A new method for increasing the probability of detecting nuclear resonance signals is demon-strated experimentally. It is well known that the detection of signals with a low signal to noise ratio (SNR) results in missed detections of false alarms. In situations where the noise is correlated or where limited data is averaging, it may not be possible to achieve a desired SNR through averaging alone. We present an alternative approach in which a feedback algorithm automatically adjusts pulse parameters so that the SNR and probability of correct detection are increased. Experimental results are presented for the detection of 14N NQR signals.

  20. A new dedicated ?-NMR/?-NQR setup for LISE-GANIL

    NASA Astrophysics Data System (ADS)

    De Rydt, M.; Lozeva, R.; Vermeulen, N.; de Oliveira Santos, F.; Grvy, S.; Himpe, P.; Stdel, C.; Thomas, J. C.; Vingerhoets, P.; Neyens, G.

    2009-12-01

    A new ?-NMR/?-NQR setup is developed to study nuclear magnetic dipole moments and electric quadrupole moments at the LISE fragment separator at GANIL. Two key elements make the new design very powerful: the homogeneous magnet and the strong radio-frequency amplifier. The combination of both makes it possible to examine a broad spectrum of magnetic dipole and electric quadrupole moments. Several factors have an influence on the detection efficiency and on the sensitivity of the setup to observe a resonant change in the ?-asymmetry: the thickness and the tilting angle of the implantation crystal, the material in the vacuum chamber, the applied magnetic field and the Q?-value of the decaying nuclei. A detailed study of these effects is made using a dedicated GEANT4 Monte Carlo simulation code.

  1. Application of a dc SQUID to rf amplification: NQR

    SciTech Connect

    Hilbert, C.; Clarke, J.; Sleator, T.; Hahn, E.L.

    1985-05-01

    Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.

  2. Zeeman shift--a tool for assignment of 14N NQR lines of nonequivalent 14N atoms in powder samples.

    PubMed

    Luznik, J; Jazbinsek, V; Pirnat, J; Seliger, J; Trontelj, Z

    2011-09-01

    The use of Zeeman perturbed 14N nuclear quadrupole resonance (NQR) to determine the ?+ and ?-14N lines in polycrystalline samples with several nonequivalent nitrogen atoms was investigated. The 14N NQR line shift due to a weak external Zeeman magnetic field was calculated, assuming isotropic distribution of EFG tensor directions. We calculated the broad line distribution of the ?+ and ?- line shifts and experimentally confirmed the calculated Zeeman field dependence of singularities (NQR peaks) in cyclotrimethylenetrinitramine (RDX) and aminotetrazole monohydrate (ATMH). The calculated and measured frequency shifts agreed well. The proposed measurement method enabled determination of which 14N NQR lines in ATMH belong to ?+ and which to ?- transitions. PMID:21783395

  3. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement

    NASA Astrophysics Data System (ADS)

    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; Iyo, Akira; Eisaki, Hiroshi

    2012-05-01

    We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) meas urements on single-crystalline Ba1-xKxFe2As2 for x = 0.27{--}1. 75As nuclear quadruple resonance frequency (?Q) 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.

  4. 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 = 0.271. 75As nuclear quadruple resonance frequency (?Q) 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 spinlattice 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.

  5. Local electric state of noncentrosymmetric superconductor Mo3Al2C revealed by Mo NQR and NMR experiments

    NASA Astrophysics Data System (ADS)

    Ihara, Y.; Kimura, Y.; Kumagai, K.; Bauer, E.; Rogl, G.; Rogl, P.

    2012-12-01

    Mo nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements were performed on a noncentrosymmetric superconductor Mo3Al2C to investigate the local electronic state at Mo nuclei, which carries the electrons responsible for superconductivity. The NQR frequency, which is linked to the electric field gradient at Mo site, was determined from 95Mo NMR spectrum and the result was verified by the independent 97Mo NQR measurement. The experimentally obtained value is compared to the result of a point charge calculation to extract the EFG induced by conduction electrons and reveal the local electronic state.

  6. 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.

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

    PubMed

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

    2015-10-01

    We report (75)As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies on the superconductor Rb(2)Cr(3)As(3) with a quasi-one-dimensional crystal structure. Below T∼100  K, the spin-lattice relaxation rate (1/T(1)) divided by temperature, 1/T(1)T, increases upon cooling down to T(c)=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/T(1) decreases rapidly below T(c) without a Hebel-Slichter peak, and follows a T(5) variation below T∼3  K, which points to unconventional superconductivity with point nodes in the gap function. PMID:26551818

  8. 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.

  9. 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

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

    NASA Astrophysics Data System (ADS)

    Lunik, 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.

  11. A Computer-controlled, Fully Automatic NMR/NQR Double Resonance Spectrometer

    NASA Astrophysics Data System (ADS)

    Zhenye, Feng; Lcken, Edwin A. C.; Diolot, Jacques

    1992-02-01

    A completely automatic computer-controlled NMR/NQR double resonance spectrometer is described. It features automatic tuning of the low, variable frequency power amplifier, thus permitting untended use over long periods, with high sensitivity and signal reproducibility. The sample is transferred between the low-frequency, zero-field region and the high-field region using compressed air and the possibility of switching on a field of several tens of gauss during the transfer of the sample is also included

  12. 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.

  13. Part I. Analyzing the distribution of gas law questions in chemistry textbooks. Part II. Chlorine-35 NQR spectra of group 1 and silver dichloromethanesulfonates

    NASA Astrophysics Data System (ADS)

    Gillette, Gabriel

    Part I. Two studies involving the gas law questions in eight high school and Advanced Placement/college chemistry textbooks were performed using loglinear analysis to look for associations among six variables. These variables included Bloom's Taxonomy (higher-order, lower-order), Book Type (high school, college), Question Format (multiple-choice, problem, short answer), Question Placement (in-chapter, end-of-chapter, test bank), Representation (macroscopic, microscopic, symbolic), and Arkansas Science Standard (conceptual, mathematical; gas laws, pressure conversion, stoichiometry). The first study, involving the conceptual gas law questions, found the Book Type and Question Placement variables had the biggest impact, each appearing in 5 of the 11 significant associations. The second study, involving the mathematical gas law questions, found the Question Placement had the biggest impact, appearing in 7 of the 11 significant associations, followed by Book Type and the Arkansas Science Standard variables, which appeared in 5 of the 11 significant associations. These studies showed that compared to the high school books, college books have fewer multiple-choice questions (compared to short-answer and problem questions), fewer in-chapter questions (compared to end-of-chapter and test bank questions), fewer questions in the chapters and more questions at the end of the chapters and fewer multiple-choice questions in and at the end of the books and more multiple-choice questions in the test banks. Part II. The dichloromethanesulfonate salts of several +1 charged cations, M+Cl2CHSO3 - (M = Li, Na, K, Rb Ag, Cs Tl) were synthesized and studied by 35Cl nuclear quadrupole resonance (NQR). Dichloromethanesulfonic acid was prepared by the methanolysis of dichloromethanesulfonyl chloride, which was neutralized with the metal carbonates to produce the corresponding metal dichloromethanesulfonate salts. This study completed the NQR investigation of the family of chloroacetates and chloromethanesulfonates of silver. The study suggests that the ability of organochlorine atoms to coordinate to silver ions decreases as the number of electron-withdrawing groups attached to carbon atom bound to the coordinating chlorine atom increases. The unusually large NQR spectral width found among M+Cl2CHCO2 - salts are not present among M+Cl2CHSO 3- salts and does not appear to be generally characteristic of the dichloromethyl family of salts.

  14. 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.

  15. Isotope ratio of Cl NQR spin-lattice relaxation times in 1D hydrogen-bonding system of tetramethylpyrazine-chloranilic acid at high temperatures

    NASA Astrophysics Data System (ADS)

    Asaji, Tetsuo

    2013-05-01

    The temperature dependences of spin-lattice relaxation time T 1 of 35Cl and 37Cl NQR were studied for the co-crystal of tetramethylpyrazine (TMP) with chloranilic acid (H2ca), TMP-H2ca, in which one-dimensional hydrogen bonding is formed by alternate arrangement of TMP and H2ca. The isotope ratio 37Cl T 1 / 35Cl T 1 was determined to be 1.0 0.1 above ca. 290 K where a steep decrease of spin-lattice relaxation time T 1 with increasing temperature was observed. In this temperature range it is suggested that the relaxation is originated from the slow fluctuation of electric field gradient (EFG). Beside EFG fluctuation due to the external-charge-density fluctuation, the small angle reorientation of the quantization axis triggered by a proton transfer motion between N...H-O and N-H...O hydrogen bonding states is proposed.

  16. Measurement of in-situ stress in salt and rock using NQR techniques

    SciTech Connect

    Schempp, E.; Hirschfeld, T.; Klainer, S.

    1980-12-01

    A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole instrumentation suitable for in-situ determinations of stress appears within the state of the art. Additional tasks required on the project are identified.

  17. Beta-detected NQR in zero field with a low energy beam of 8Li+

    NASA Astrophysics Data System (ADS)

    Salman, Z.; Kiefl, R. F.; Chow, K. H.; MacFarlane, W. A.; Kreitzman, S. R.; Arseneau, D. J.; Daviel, S.; Levy, C. D. P.; Maeno, Y.; Poutissou, R.

    2006-03-01

    Beta-detected nuclear quadrupole resonances ( ?-NQR) in zero field are observed using a beam of low energy highly polarized radioactive Li+8. The resonances were detected in SrTiO 3, Al 2O 3 and Sr 2RuO 4 single crystals by monitoring the beta-decay anisotropy as a function of a small audio frequency magnetic field. The resonances show clearly that Li+8 occupies one site with non-cubic symmetry in SrTiO 3, two in Al 2O 3 and three sites in Sr 2RuO 4. The resonance amplitude and width are surprisingly large compared to the values expected from transitions between the |2>?|1> spin states, indicating a significant mixing between the |m> quadrupolar split levels.

  18. 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.

  19. 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.

  20. 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{sub 5}H{sub 5}) and Sn({eta}{sup 1}-C{sub 5}H{sub 5}){sub 4}. This work was undertaken in the hope of gaining insight into the intramolecuhrr dynamics, specifically which fluxional processes exist in the solid state, by what mechanism rearrangements are occurring, and the activation energies by which these processes are governed.

  1. NQR experiments on Sc-Y alloys at very low temperatures. [Absolute thermometry below 500[mu]K

    SciTech Connect

    Pollack, L.; Smith, E.N.; Richardson, R.C. )

    1992-10-01

    The authors performed Nuclear Quadrupole Resonance (NQR) experiments on an alloy of scandium and yttrium. They find that the characteristic resonance frequencies in zero external field are 50% larger than in pure scandium. This increase in frequency makes the Sc-Y alloy a better candidate for absolute thermometry below 500 [mu]K. However, the spin-lattice relaxation time of this alloy is more than an order of magnitude longer than in the pure scandium. In addition, an abrupt increase in the Korringa constant was observed for temperatures below 5mK.

  2. New perspectives in the PAW/GIPAW approach: J(P-O-Si) coupling constants, antisymmetric parts of shift tensors and NQR predictions.

    PubMed

    Bonhomme, Christian; Gervais, Christel; Coelho, Cristina; Pourpoint, Frédérique; Azaïs, Thierry; Bonhomme-Coury, Laure; Babonneau, Florence; Jacob, Guy; Ferrari, Maude; Canet, Daniel; Yates, Jonathan R; Pickard, Chris J; Joyce, Siân A; Mauri, Francesco; Massiot, Dominique

    2010-12-01

    In 2001, Pickard and Mauri implemented the gauge including projected augmented wave (GIPAW) protocol for first-principles calculations of NMR parameters using periodic boundary conditions (chemical shift anisotropy and electric field gradient tensors). In this paper, three potentially interesting perspectives in connection with PAW/GIPAW in solid-state NMR and pure nuclear quadrupole resonance (NQR) are presented: (i) the calculation of J coupling tensors in inorganic solids; (ii) the calculation of the antisymmetric part of chemical shift tensors and (iii) the prediction of (14)N and (35)Cl pure NQR resonances including dynamics. We believe that these topics should open new insights in the combination of GIPAW, NMR/NQR crystallography, temperature effects and dynamics. Points (i), (ii) and (iii) will be illustrated by selected examples: (i) chemical shift tensors and heteronuclear (2)J(P-O-Si) coupling constants in the case of silicophosphates and calcium phosphates [Si(5)O(PO(4))(6), SiP(2)O(7) polymorphs and α-Ca(PO(3))(2)]; (ii) antisymmetric chemical shift tensors in cyclopropene derivatives, C(3)X(4) (X = H, Cl, F) and (iii) (14)N and (35)Cl NQR predictions in the case of RDX (C(3)H(6)N(6)O(6)), β-HMX (C(4)H(8)N(8)O(8)), α-NTO (C(2)H(2)N(4)O(3)) and AlOPCl(6). RDX, β-HMX and α-NTO are explosive compounds. PMID:20589728

  3. 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.

  4. 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.

  5. Stereoelectronic structure and 35Cl NQR parameters of 4-(trichlorgermyl)butan-2-one using ab initio calculations

    NASA Astrophysics Data System (ADS)

    Feshin, V. P.; Feshina, E. V.

    2012-03-01

    The results of ab initio calculations at the RHF/6-31G(d) and MP2/6-31G(d) levels of two stable structures of the 4-(trichlorgermyl)butan-2-one molecule with total optimization of their geometry have been represented. The structure with pentacoordinated Ge atom is energetically more advantageous as compared with that with tetracoordinated one. Using these results, the 35Cl nuclear quadrupole resonance (NQR) frequencies and asymmetry parameters of the electric field gradient (EFG) at the 35Cl nuclei in molecule with pentacoordinated Ge atom have been assessed, the frequencies satisfactorily agreeing with experimental data. Calculations at the RHF/6-31G(d) level have been performed also at various Ge⋯O distances. It has been demonstrated that convergence of the Ge and O coordination centers leads to the increase of positive charge at the Ge coordination center and of negative charge at the O coordination center, at that, electron density from the Ge atom shifts mainly to the axial Cl atom and from the C atom of carbonyl group - to its O atom. The electron density transfer from the O to Ge atom does not occur.

  6. 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.

  7. 127I NQR, 1H NMR and crystal structure of a novel compound, guanidinium heptaiodomercurate(II) [C(NH 2) 3] 3Hg 2I 7

    NASA Astrophysics Data System (ADS)

    Terao, Hiromitsu; Kai, Yoshihiko; Gesing, Thorsten M.; Ishihara, Hideta; Furukawa, Yoshihiro; Gowda, B. Thimme

    2009-08-01

    The crystal structure of [C(NH 2) 3] 3Hg 2I 7 crystallizes in the monoclinic space group C2/ c with a = 10.301(2), b = 11.919(2), c = 22.143(4) , ? = 100.50(3), and Z = 4. The asymmetric unit of the structure consists of an Hg 2I 73- anion and three guanidinium cations [C(NH 2) 3] +. The Hg 2I 73- anion is composed of two distorted HgI 4 tetrahedra which share an apex of I(4) atom and are related to each other by the C 2 axis. The lengths of the four Hg-I bonds of the tetrahedron are different, the longest being the bridging Hg-I(4) bond. In accordance with the crystal structure, four 127I NQR resonance lines have been observed and are assigned to m = 1/2 ? 3/2 transitions. With decreasing temperature one line assigned to the bridging I(4) atom faded out around 250 K. The temperature dependence of 1H NMR T1 has been analyzed by postulating the C 3 reorientations of two crystallographically independent cations with the BPP and the Arrhenius type relations. The hydrogen bond interactions N-H⋯I are important in the architecture of the crystal structure, which manifest themselves on the differences in the Hg-I bond lengths, in the NQR frequencies, and in the activation energies of the cation reorientations.

  8. Zero-field NMR study on a spin glass: iron-doped 2H-niobium diselenide

    SciTech Connect

    Chen, M C

    1982-01-01

    Spin echoes are used to study the /sup 93/Nb NQR in 2H-NbSe/sub 2/Fe/sub x/. Measured are (intensity) x (temperature), and T/sub 1P/ (spin-lattice relaxation parameter) and T/sub 2/ (spin-spin relaxation time) as a function of temperature. Data reveal dramatic differences between non-spin glass samples (x = 0, 0.25%, 1% and 5%) and spin glass samples (x = 8%, 10% and 12%). All of the NQR results and the model calculation of the correlation times of Fe spins are best described by the phase transition picture of spin glasses.

  9. 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 and bpe) but different structures have also been investigated. Photoluminescence studies show that the guest-free samples of these compounds also exhibit quenching or enhancement phenomena, when exposed to the vapors of two different types of analyte molecules having electron rich and electron deficient functional groups. The origin of such effect can be well understood and explained based on molecular orbital and band structure calculations, as well as the comparison of their redox potentials. In addition, synthesis and characterization of some new MMOFs, composed of V-shaped dicarboxylic acid and selected diamine ligands are briefly discussed. Clearly, ligands play an important role in the crystal structure formation as well as pore characteristics of the resultant MMOFs.

  10. 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 ? and the T dependence of 1/T1T?, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  11. 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 ? and the T dependence of 1/T1T?, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  12. 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.

  13. 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.

  14. Phase transition study of confined water molecules inside carbon nanotubes: hierarchical multiscale method from molecular dynamics simulation to ab initio calculation.

    PubMed

    Javadian, Soheila; Taghavi, Fariba; Yari, Faramarz; Hashemianzadeh, Seyed Majid

    2012-09-01

    In this study, the mechanism of the temperature-dependent phase transition of confined water inside a (9,9) single-walled carbon nanotube (SWCNT) was studied using the hierarchical multi-scale modeling techniques of molecular dynamics (MD) and density functional theory (DFT). The MD calculations verify the formation of hexagonal ice nanotubes at the phase transition temperature T(c)=275K by a sharp change in the location of the oxygen atoms inside the SWCNT. Natural bond orbital (NBO) analysis provides evidence of considerable intermolecular charge transfer during the phase transition and verifies that the ice nanotube contains two different forms of hydrogen bonding due to confinement. Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) analyses were used to demonstrate the fundamental influence of intermolecular hydrogen bonding interactions on the formation and electronic structure of ice nanotubes. In addition, the NQR analysis revealed that the rearrangement of nano-confined water molecules during the phase transition could be detected directly by the orientation of ¹⁷O atom EFG tensor components related to the molecular frame axes. The effects of nanoscale confinements in ice nanotubes and water clusters were analyzed by experimentally observable NMR and NQR parameters. These findings showed a close relationship between the phase behavior and orientation of the electronic structure in nanoscale structures and demonstrate the usefulness of NBO and NQR parameters for detecting phase transition phenomena in nanoscale confining environments. PMID:23085156

  15. Towards ferromagnetic quantum criticality in FeGa3 -xGex :71Ga NQR as a zero-field microscopic probe

    NASA Astrophysics Data System (ADS)

    Majumder, M.; Wagner-Reetz, M.; Cardoso-Gil, R.; Gille, P.; Steglich, F.; Grin, Y.; Baenitz, M.

    2016-02-01

    71Ga NQR, magnetization, and specific-heat measurements have been performed on polycrystalline Ge-doped FeGa3 samples. A crossover from an insulator to a correlated local moment metal in the low-doping regime and the evolution of itinerant ferromagnet upon further doping is found. For the nearly critical concentration at the threshold of ferromagnetic order, xC=0.15, 71(1 /T1T ) exhibits a pronounced T-4 /3 power law over two orders of magnitude in temperature, which indicates three-dimensional quantum critical ferromagnetic fluctuations. Furthermore, for the ordered x =0.2 sample (TC≈6 K), 71(1 /T1T ) could be fitted well in the frame of Moriya's self-consistent renormalization theory for weakly ferromagnetic systems with 1 /T1T ˜χ . In contrast to this, the low-doping regime nicely displays local moment behavior where 1 /T1T ˜χ2 is valid. For T →0 , the Sommerfeld ratio γ =(C /T ) is enhanced (70 mJ /mole K2 for x =0.1 ) , which indicates the formation of heavy 3 d electrons.

  16. An insight into prototropism and supramolecular motifs in solid-state structures of allopurinol, hypoxanthine, xanthine, and uric acid. A H-?N NQDR spectroscopy, hybrid DFT/QTAIM, and Hirshfeld surface-based study.

    PubMed

    Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Seliger, Janez; agar, Veselko; Kazimierczuk, Zygmunt

    2014-09-18

    Allopurinol (1,5-dihydro-4H-pyrazolo [3,4-d]pyrimidin-4-one), the active pharmaceutical ingredient (API) of the drugs applied for the treatment of gout and tumor lysis syndrome, recently discovered to have multifaceted therapeutic potential, and hypoxanthine which is a naturally occurring purine have been studied experimentally in the solid state by (1)H-(14)N NMR-NQR double resonance. Twelve (14)N resonance frequencies have been detected at 295 K and assigned to two pairs of two kinds of nitrogen sites (-N? and -NH) in each compound. The experimental results are supported by and interpreted with the help of quantum theory of atoms in molecules (QTAIM)/density functional theory (DFT) calculations. The factors, such as the substituent effect, in particular the shift of nitrogen from position 7 (as in hypoxanthine) to position 8 (as in allopurinol), hybridization, possible prototropic tautomerism, and the pattern of intermolecular bonding, have been taken into account in (1)H-(14)N NMR-NQR spectra interpretation. This study demonstrates the advantages of combining NQR, DFT/QTAIM, and Hirshfeld surface analysis to extract detailed information on electron density distribution and complex H-bonding networks in crystals of purinic type heterocycles, relevant in pharmacological processes. In the absence of X-ray data for xanthine, the NQR parameters supported by DFT/QTAIM calculations and Hirshfeld surface analysis were proved to be valuable tools for clarifying the details of crystalline packing and predicting an unsolved crystalline structure of xanthine. The influence of a decrease in purine ring conjugation level upon oxidation on the biological activity of allopurinol, a xanthine oxidase (XO) enzyme inhibitor, which blocks the conversion of hypoxanthine to xanthine and subsequently xanthine to uric acid, is also discussed. PMID:25079386

  17. 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.

  18. Topology of the interactions pattern in pharmaceutically relevant polymorphs of methylxanthines (caffeine, theobromine, and theophiline): combined experimental (H-?N nuclear quadrupole double resonance) and computational (DFT and Hirshfeld-based) study.

    PubMed

    Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Olejniczak, Grzegorz A; Seliger, Janez; agar, Veselko

    2014-09-22

    Three anhydrous methylxanthines: caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) and its two metabolites theophylline (1,3-dimethylxanthine; 1,3-dimethyl-7H-purine-2,6-dione) and theobromine (3,7-dimethyl-xanthine; 3,7-dimethyl-7H-purine-2,6-dione), which reveal multifaceted therapeutic potential, have been studied experimentally in solid state by (1)H-(14)N NMR-NQR (nuclear magnetic resonance-nuclear quadrupole resonance) double resonance (NQDR). For each compound the complete NQR spectrum consisting of 12 lines was recorded. The multiplicity of NQR lines indicates the presence of a stable ? form of anhydrous caffeine at 233 K and stable form II of anhydrous theobromine at 213 K. The assignment of signals detected in NQR experiment to particular nitrogen atoms was made on the basis of quantum chemistry calculations performed for monomer, cluster, and solid at the DFT/GGA/BLYP/DPD level. The shifts due to crystal packing interactions were evaluated, and the multiplets detected by NQR were assigned to N(9) in theobromine and N(1) and N(9) in caffeine. The ordering theobromine > theophylline > caffeine site and theophylline < theobromine < caffeine according to increasing electric field gradient (EFG) at the N(1) and N(7) sites, respectively, reflects the changes in biological activity profile of compounds from the methylxanthines series (different pharmacological effects). This difference is elucidated on the basis of the ability to form intra- and intermolecular interactions (hydrogen bonds and ?? stacking interactions). The introduction of methyl groups to xanthine restricts the ability of nitrogen atoms to participate in strong hydrogen bonds; as a result, the dominating effect shifts from hydrogen bond (theobromine) to ?? stacking (caffeine). Substantial differences in the intermolecular interactions in stable forms of methylxanthines differing in methylation (site or number) were analyzed within the Hirshfeld surface-based approach. The analysis of local environment of the nitrogen nucleus permitted drawing some conclusions on the nature of the interactions required for effective processes of recognition and binding of a given methylxanthine to A1-A(2A) receptor (target for caffeine in the brain). Although the interactions responsible for linking neighboring methylxanthines molecules in crystals and methylxanthines with targets in the human organism can differ significantly, the knowledge of the topology of interactions provides reliable preliminary information about the nature of this binding. PMID:25184363

  19. Investigation of H-bonding and halogen-bonding effects in dichloroacetic acid: DFT calculations of NQR parameters and QTAIM analysis.

    PubMed

    Esrafili, Mehdi D

    2012-12-01

    A theoretical study was performed to examine hydrogen and halogen bonds properties in gas phase and crystalline dichloroacetic acid (DCAA). The specific pattern of O-H???O, C-H???O, HCl, Cl???O and Cl???Cl interactions in DCAA dimers is described within the quantum theory of atoms in molecules (QTAIM) formalism. Based on QTAIM results, a partial covalent character is attributed to the O-H???O hydrogen bonds in DCAA, whereas all the C-H???O, ClO and Cl???Cl intermolecular interactions are weak and basically electrostatic in nature. MP2/6-311++G** calculations indicate that the interaction energies for DCAA dimers lie in the range between -0.40 and -14.58kcalmol(-1). One of the most important results of this study is that, according to energy decomposition analyses, halogen bonds are largely dependent on both electrostatic and dispersion interactions. For those nuclei participating in the hydrogen-bonding and halogen-bonding interactions, nuclear quadrupole coupling constants exhibit significant changes on going from the isolated molecule model to the crystalline DCAA. Of course, the magnitude of these changes at each nucleus depends directly on its amount of contribution to the interactions. PMID:22736221

  20. 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 process were obtained from measurements of spin-lattice relaxation vs. pressure. From the NMR measurements of Nafion films containing methanol, it was found that the molecular motion is much more rapid than the molecular motion of water in Nafion membranes.

  1. Zero-field NMR study on a spin-glass: Iron-doped 2H-niobium diselenide

    NASA Astrophysics Data System (ADS)

    Chen, M. C.; Slichter, C. P.

    1983-01-01

    We describe a zero-field NMR study attempting to resolve the controversy between phase-transition theories and nonequilibrium glasslike theories of the spin-glass transition. The spin dynamics of Fe spins in 2H-NbSe2Fex is probed through its influence on the nuclear quadrupole resonance (NQR) of 93Nb nuclei. The spin-echo method is used. We measure intensity times temperature, T1P (spin-lattice relaxation parameter), and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic differences between non-spin-glass samples (x=0, 0.25, 1, and 5 at.%) and spin-glass samples (x=8, 10, and 12 at.%). Defining the spin-glass transition temperature Tg by the cusp of the susceptibility-versus-temperature curve, we find well-defined minima at T=Tg in intensity times temperature, T1P and T2 as a function of temperature. Deduction of a correlation time of Fe spins from T1P and T2 is complicated by the intensity changes which imply that one observes different groups of nuclei at different temperatures. We propose a two-correlation-time model, which utilizes the anisotropy of the exchange interaction, to overcome this difficulty. All of our NQR results and the model calculation of the correlation times of Fe spins are best described by the phase-transition picture of spin-glasses.

  2. Specific Heat and Nuclear Quadrupole Resonance Study of Thiourea-Hexachloroethane Inclusion Compound

    NASA Astrophysics Data System (ADS)

    Chekhova, G. N.; Goren, S. D.; Krieger, Ju. H.; Linsky, D.; Lusternik, V.; Panich, A. M.; Semenov, A. R.; Voronel, A.

    2000-02-01

    Specific heat and 35Cl nuclear quadrupole resonance (NQR) measurements of the channel thio-urea-hexachloroethane inclusion compound are presented. Experimental NQR data confirm the results of atom-atom potential calculations that the guest sublattice comprises two types of nearly commensurate finite molecular chains, having different structure and separated by domain walls. Specific heat measurements show phase transition near 96 K.

  3. 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.

  4. 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.

  5. Utilization of pure nuclear quadrupole resonance spectroscopy for the study of pharmaceutical crystal forms.

    PubMed

    Prez, S C; Cerioni, L; Wolfenson, A E; Faudone, S; Cuffini, S L

    2005-07-14

    Solid-state physical characterization of a pharmaceutical substance is necessary for successful development and approval of the final product. Different physical analytical techniques are available to do so: X-ray diffraction (XRD), IR, Raman, DSC, TG and NMR. Moreover, all of them detect the presence of excipients perturbing the analysis of the pure substance in low doses. In order to study polymorphism and pseudo polymorphism of drug, this paper introduces possible applications of pure nuclear quadrupole resonance, as a non-destructive technique in qualitative and quantitative approaches. Chlorpropamide and diclofenac sodium were used as examples. Unlike the mentioned techniques, the nuclear quadrupole resonance (NQR) signal of pharmaceutical compounds is not perturbed by the presence of solid excipient or other substances unless they possess resonance frequencies in the same frequency range of the compound studied. PMID:15913931

  6. 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.

  7. Application of two-dimensional exchange nuclear magnetic resonance techniques for the study of incommensurate solids

    NASA Astrophysics Data System (ADS)

    Muntean, Ligia Aurora

    This dissertation includes a study of atomic dynamics in incommensurate systems by specialized nuclear magnetic resonance (NMR) techniques, such as two-dimensional (2D) exchange NMR, and Hahn spin-echo decay. The atomic dynamics described by the diffusion-like motion of the modulation wave in incommensurate phases is one of the subjects of condensed matter physics that is not fully understood and has attracted a great deal of attention in recent years. Our Hahn spin-echo decay and 2D exchange and exchange-difference NMR experiments have contributed to understanding some of the aspects of this debated subject and have brought conclusive experimental evidence for the existence of the modulation wave diffusion in Rb2ZnCl 4 and BaNaNb5O15. We performed 87Rb NMR and 35Cl nuclear quadrupole resonance (NQR) Hahn spin echo magnetization decay measurements in the incommensurate (I) phase of Rb2ZnCl4. From these measurements we obtained values for the diffusion coefficients for 87Rb NMR and 35Cl NQR and found them to be similar. This fact strongly supports the existence of modulation wave diffusion in the I phase, that should affect both Rb and Cl ions comparably. We also used 87Rb 2D exchange-difference NMR to study atomic motions in the incommensurate (I) and paraelectric (P) phases, to elucidate the nature of the I-P transition. The P phase results are identified as normal modes arising from simultaneous reorientations of ZnCl4 tetrahedra and corresponding Rb ions displacements between two sites. These normal modes freeze out in the I phase and change to the diffusion-like motion of the modulation wave. This dissertation also includes a study of modulation wave dynamics in the I phase of barium sodium niobate (BSN) by 2D exchange NMR. The modulation wave diffusion has been previously inferred in BSN from a complementary experiment, the Hahn spin-echo decay. However, since this experiment cannot unambiguously distinguish between different types of motional mechanisms, the modulation wave diffusion interpretation of the Hahn echo experimental results could still be under question. Our 93Nb 2D exchange NMR data provide additional strong evidence for the existence of progressive diffusion-like motion of the modulation wave and rules out a two-site jump model in BSN.

  8. 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.

  9. Applications of nuclear quadrupole resonance spectroscopy in drug development.

    PubMed

    Latosin?ska, Jolanta N

    2007-02-01

    In this review, fundamentals of nuclear quadrupole resonance (NQR) spectroscopy are briefly outlined. Examples of its applications in drug development are discussed to demonstrate that the NQR method is a sophisticated, non-destructive and valuable analytical technique for studying pharmaceuticals, providing effective assistance at the two main steps of drug development: the physical and chemical characterization of the active pharmaceutical ingredients (API) at the analytical step and API development. This review covers different aspects of the use of NQR spectroscopy for drug development and analysis and illustrates the power and versatility of this method in the determination of impurities, polymorphic forms, the drug's structure and conformation, characterization of the interactions between the drug and ligands, search for analogs (second- or third-generation drugs) and the drug's thermal stability. Lastly, NQR advantages and restrictions in the aspect of application in drug development studies are summarized. PMID:23496079

  10. Optimal filtering in multipulse sequences for nuclear quadrupole resonance detection

    NASA Astrophysics Data System (ADS)

    Osokin, D. Ya.; Khusnutdinov, R. R.; Mozzhukhin, G. V.; Rameev, B. Z.

    2014-05-01

    The application of the multipulse sequences in nuclear quadrupole resonance (NQR) detection of explosive and narcotic substances has been studied. Various approaches to increase the signal to noise ratio (SNR) of signal detection are considered. We discussed two modifications of the phase-alternated multiple-pulse sequence (PAMS): the 180 pulse sequence with a preparatory pulse and the 90 pulse sequence. The advantages of optimal filtering to detect NQR in the case of the coherent steady-state precession have been analyzed. It has been shown that this technique is effective in filtering high-frequency and low-frequency noise and increasing the reliability of NQR detection. Our analysis also shows the PAMS with 180 pulses is more effective than PSL sequence from point of view of the application of optimal filtering procedure to the steady-state NQR signal.

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

    PubMed

    Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Szafra?ski, Marek; Seliger, Janez; agar, 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). 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=3.106) the formation of alternative O'H?O bonds (O'?O=2.785) is possible within the 1D ribbons. The adjacent ribbons are further stabilised by O'H?O bonds (O'?O=2.951). 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

  12. Pulsed Bromine-81 Nuclear Quadrupole Resonance Spectroscopy of Brominated Flame Retardants and Associated Polymer Blends.

    NASA Astrophysics Data System (ADS)

    Mrse, Anthony A.; Lee, Youngil; Bryant, Pamela L.; Fronczek, Frank R.; Butler, Leslie G.; Simeral, Larry S.

    1998-03-01

    The dispersion of brominated flame retardants in polymers is monitored with bromine-81 NQR using a pulse NQR spectrometer. The NQR spectrometer consists of a homemade 10-300 MHz single-channel NMR console coupled to a broadly tunable probe. The probe is a loop-gap resonator usable from 220 to 300 MHz, and automatically tuned over any 5 MHz region with a stepping motor and an RF bidirectional coupler. Bromine-81 NQR spectra of several brominated aromatic flame retardants, as pure materials and in polymers, were recorded in the range of 227 to 256 MHz in zero applied magnetic field. Two factors affect the bromine-79/81 NQR transition frequencies in brominated aromatics: electron withdrawing substituents on the ring and intermolecular contacts with other bromine atoms in the crystal structure. An existing model for substituents is updated and a point charge model for the intermolecular contacts is developed. In this study, we exploit the bromine-81 NQR transition frequency dependence on intermolecular contacts to learn how a flame retardant is dispersed in a polymer matrix.

  13. 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

  14. Purification and characterization of the recombinant Na(+)-translocating NADH:quinone oxidoreductase from Vibrio cholerae.

    PubMed

    Barquera, Blanca; Hellwig, Petra; Zhou, Weidong; Morgan, Joel E; Hse, Claudia C; Gosink, Khoosheh K; Nilges, Mark; Bruesehoff, Peter J; Roth, Annette; Lancaster, C Roy D; Gennis, Robert B

    2002-03-19

    The nqr operon from Vibrio cholerae, encoding the entire six-subunit, membrane-associated, Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR), was cloned under the regulation of the P(BAD) promoter. The enzyme was successfully expressed in V. cholerae. To facilitate molecular genetics studies of this sodium-pumping enzyme, a host strain of V. cholerae was constructed in which the genomic copy of the nqr operon was deleted. By using a vector containing a six-histidine tag on the carboxy terminus of the NqrF subunit, the last subunit in the operon, the recombinant enzyme was readily purified by affinity chromatography in a highly active form from detergent-solubilized membranes of V. cholerae. The recombinant enzyme has a high specific activity in the presence of sodium. NADH consumption was assessed at a turnover number of 720 electrons per second. When purified using dodecyl maltoside (DM), the isolated enzyme contains approximately one bound ubiquinone, whereas if the detergent LDAO is used instead, the quinone content of the isolated enzyme is negligible. Furthermore, the recombinant enzyme, purified with DM, has a relatively low rate of reaction with O(2) (10-20 s(-1)). In steady state turnover, the isolated, recombinant enzyme exhibits up to 5-fold stimulation by sodium and functions as a primary sodium pump, as reported previously for Na(+)()-NQR from other bacterial sources. When reconstituted into liposomes, the recombinant Na(+)-NQR generates a sodium gradient and a Delta Psi across the membrane. SDS-PAGE resolves all six subunits, two of which, NqrB and NqrC, contain covalently bound flavin. A redox titration of the enzyme, monitored by UV-visible spectroscopy, reveals three n = 2 redox centers and one n = 1 redox center, for which the presence of three flavins and a 2Fe-2S center can account. The V. cholerae Na(+)-NQR is well-suited for structural studies and for the use of molecular genetics techniques in addressing the mechanism by which NADH oxidation is coupled to the pumping of Na(+) across the membrane. PMID:11888296

  15. 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.

  16. 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, Frdric 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)22H2O), 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., ?Q) to nearly an order-of-magnitude greater precision than competing SSNMR and nuclear quadrupole resonance (NQR) approaches. Samples of AgReO4 and Ca(ReO4)22H2O 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)22H2O, 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 provided for NH4ReO4, NaReO4 and RbReO4. These calculations are able to reproduce many of the experimental trends in rhenium ?iso values and EFG tensor magnitudes. Using KReO4 as a prototypical perrhenate-containing system, we establish a correlation between the tetrahedral shear strain parameter (|?|) and the nuclear electric quadrupolar coupling constant (CQ), which enables the refinement of the structure of ND4ReO4. Shortcomings in traditional DFT approaches, even when including relativistic effects via the zeroth-order regular approximation (ZORA), for calculating rhenium NMR tensor parameters are identified for Re2(CO)10. PMID:25790263

  17. Crossover behavior from magnetism to superconductivity in Ce xCu 2Si 2

    NASA Astrophysics Data System (ADS)

    Ishida, K.; Kawasaki, Y.; Tabuchi, K.; Kashima, K.; Kitaoka, Y.; Asayama, K.; Geibel, C.; Steglich, F.

    1999-01-01

    Cu-NQR studies have been performed to clarify the ground-state characteristics in a series of Ce xCu 2Si 2 system. It was found that the ground state evolves from magnetically ordered state at x=0.975 to heavy-electron superconducting state at x=1.025. At the border between the two phases ( x=0.99), the novel magnetic character survives even at the lowest temperature. We propose that this magnetic state may be a dynamical SDW state oscillating with finite frequencies comparable to Cu-NQR frequency (?3 MHz).

  18. 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 Tmax20 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.

  19. 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 encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.

  20. 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.

  1. Zero-field splittings of NQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. A.; Orlov, V. G.; Morgunov, V. G.; Shlykov, M. P.

    2007-11-01

    Local magnetic fields up to 250 G were earlier found by measuring the NQI parameters in bismuth(III) oxy compounds conventionally considered as diamagnets, a strong increase in the 209Bi line intensities being observed in external magnetic fields. An approach based on registration of the quadrupole spin-echo envelopes enabled to reveal small (within an inhomogeneous line broadening) splittings in some other compounds of this type. The modeling of time dependence of the quadrupole spin echo amplitude indicated that modulations of the spin echo envelope in BaBiO2Cl and Bi3B5O12 resulted from weak (?5 G) local magnetic fields. By using this approach, it was found that an increase in the 209Bi resonance intensity in external magnetic fields is related to an influence of the fields on the nuclear spin-spin relaxation rate for the appropriate compounds.

  2. Zero-field splittings of NQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. A.; Orlov, V. G.; Morgunov, V. G.; Shlykov, M. P.

    Local magnetic fields up to 250 G were earlier found by measuring the NQI parameters in bismuth(III) oxy compounds conventionally considered as diamagnets, a strong increase in the 209Bi line intensities being observed in external magnetic fields. An approach based on registration of the quadrupole spin-echo envelopes enabled to reveal small (within an inhomogeneous line broadening) splittings in some other compounds of this type. The modeling of time dependence of the quadrupole spin echo amplitude indicated that modulations of the spin echo envelope in BaBi02Cl and Bi3B5012 resulted from weak (?5 G) local magnetic fields. By using this approach, it was found that an increase in the 209Bi resonance intensity in external magnetic fields is related to an influence of the fields on the nuclear spin-spin relaxation rate for the appropriate compounds.

  3. Determination of the sign of the electric field gradient in indium by nuclear resonance

    SciTech Connect

    Pollack, L.; Smith, E.N.; Richardson, R.C.

    1997-01-01

    The authors have studied the temperature dependence of two of the four magnetic-field perturbed NQR lines in indium. Their results indicate that the sign of the internal electric field gradient (EFG) is positive, in accord with the recent heat capacity measurements of the ISSP group and one recent theoretical prediction. They also discuss the implications of the sign of the EFG on the use of indium as an absolute thermometer below 1 mK.

  4. 63,65Cu Nuclear Resonance Study of the Coupled Spin Dimers and Chains Compound Cu2Fe2Ge4O13

    NASA Astrophysics Data System (ADS)

    Kikuchi, Jun; Nagura, Shiro; Murakami, Kazumasa; Masuda, Takatsugu; Redhammer, Gnther J.

    2013-03-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) of Cu have been measured in a coupled spin dimers and chains compound Cu2Fe2Ge4O13. Cu NQR has also been measured in an isostructural material Cu2Sc2Ge4O13 including only spin dimers. Comparison of the temperature dependence of the 63Cu nuclear spin--lattice relaxation rate between the two compounds reveals that the Fe chains in Cu2Fe2Ge4O13 do not change a spin gap energy of the Cu dimers from that in Cu2Sc2Ge4O13, contributing additionally to the relaxation rate at the Cu site. A modestly large internal field of 3.39 T was observed at the Cu site in the antiferromagnetic state of Cu2Fe2 Ge4O13 at 4.2 K, which is partly because of quantum reduction of the ordered moment of a Cu atom. The internal field and the ordered moment of Cu are noncollinear due to large anisotropy of the hyperfine interaction at the Cu site. A model analysis of the internal field based on the fourfold planar coordination of Cu suggests that a 3d hole of the Cu2+ ion is mainly in the d(x2-y2) orbital state.

  5. 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

  6. Cu nuclear magnetic resonance of aligned single crystals of YBa/sub 2/Cu/sub 3/O/sub 7/. sqrt. /sub delta/

    SciTech Connect

    Pennington, C.H.; Durand, D.J.; Zax, D.B.; Slichter, C.P.; Rice, J.P.; Ginsberg, D.M.

    1988-05-01

    There are two types of Cu sites in YBa/sub 2/Cu/sub 3/O/sub 7/..sqrt../sub delta/, plane and chain. One gives a nuclear quadrupole resonance (NQR) at 22.0 MHz, the other at 31.5 MHz. Measurements of nuclear spin-lattice relaxation time in the superconducting state show that the 31.5-MHz site has a much larger energy gap (as though its T/sub c/ were 200 K), but different experimental workers have differed as to whether this is the chain or plane site. We report nuclear magnetic resonance (NMR) studies at 81.1 kG and 100 K on oriented single crystals, and conclude from symmetry arguments that the 31.5-MHz NQR arises from the plane site.

  7. 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.

  8. 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.

  9. 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

  10. Nuclear quadrupole interactions and charge localization in HgBa 2CuO 4 + ? with different oxygen content

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Antipov, E. V.; Hoffmann, W.; Lders, K.

    1997-02-01

    Variation of the oxygen content ? in HgBa 2CuO 4 + ? (Hg-1201) provides a good opportunity to study the influence of oxygen doping on nuclear quadrupole interactions (NQI) and charge localisation in different regions of the ( Tc- ?) phase diagram. We performed 63,65Cu Nuclear Quadrupole Resonance (NQR) studies on a series of HgBa 2CuO 4 + ? samples with different oxygen content ?. Based on the experimental NQR spectra of the Hg-1201 compounds and the known copper NQR frequency for the undoped Nd 2CuO 4 a phenomenological method is developed to analyze the NQI in high temperature superconductors (HTSC) including both, the on-site electric field gradient (EFG) and the lattice contribution in the EFG. Using this method we estimated the Sternheimer antishielding factor ?? = -16.2 for Cu 2+ and the hole concentration nx2- y2 on the copper 3d x2- y2 orbital. The nx2- y2 value rises monotonously with increasing doping level over the whole Hg-1201 sample series and is the main factor causing the increase of quadrupole frequency vQ. No saturation effect on the copper hole doping process has been found at high oxygen content level.

  11. 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 thephysiological capabilities of the bacterial periplasm, and they also clarify a possiblemechanism by which flavoproteins are generated. PMID:26626129

  12. 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

  13. 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.

  14. Mechanism of metallization and superconductivity suppression in YBa2(Cu0.97 Zn0.03)3 O6.92 revealed by 67Zn NQR

    NASA Astrophysics Data System (ADS)

    Pelc, D.; Poek, M.; Despoja, V.; Sunko, D. K.

    2015-08-01

    We measure the nuclear quadrupole resonance signal on the Zn site in nearly optimally doped YBa2Cu3O6.92, when Cu is substituted by 3% of isotopically pure 67Zn. We observe that Zn creates large insulating islands, confirming two earlier conjectures: that doping provokes an orbital transition in the CuO2 plane, which is locally reversed by Zn substitution, and that the islands are antiferromagnetic. Also, we find that the Zn impurity locally induces a breaking of the D4 symmetry. Cluster and DFT calculations show that the D4 symmetry breaking is due to the same partial lifting of degeneracy of the nearest-neighbor oxygen sites as in the LTT transition in {La}{}2-xBaxCuO4, similarly well-known to strongly suppress superconductivity (SC). These results show that in-plane oxygen 2p5 orbital configurations are principally involved in the metallicity and SC of all high-Tc cuprates, and provide a qualitative symmetry-based constraint on the SC mechanism.

  15. ATBC Study - Study Details

    Cancer.gov

    The Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study was conducted in Finland as a joint project between the National Institute for Health and Welfare of Finland and the US National Cancer Institute (NCI) . The overall design, rationale, objectives, and initial results of this intervention study have been published1,2. Briefly, this was a randomized, double-blind, placebo-controlled, primary prevention trial to determine whether daily supplementation with alpha-tocopherol, beta-carotene, or both would reduce the incidence of lung or other cancers among male smokers.

  16. Light-induced transcriptional responses associated with proteorhodopsin-enhanced growth in a marine flavobacterium.

    PubMed

    Kimura, Hiroyuki; Young, Curtis R; Martinez, Asuncion; Delong, Edward F

    2011-10-01

    Proteorhodopsin (PR) is a photoprotein that functions as a light-driven proton pump in diverse marine Bacteria and Archaea. Recent studies have suggested that PR may enhance both growth rate and yield in some flavobacteria when grown under nutrient-limiting conditions in the light. The direct involvement of PR, and the metabolic details enabling light-stimulated growth, however, remain uncertain. Here, we surveyed transcriptional and growth responses of a PR-containing marine flavobacterium during carbon-limited growth in the light and the dark. As previously reported (Gmez-Consarnau et al., 2007), Dokdonia strain MED134 exhibited light-enhanced growth rates and cell yields under low carbon growth conditions. Inhibition of retinal biosynthesis abolished the light-stimulated growth response, supporting a direct role for retinal-bound PR in light-enhanced growth. Among protein-coding transcripts, both PR and retinal biosynthetic enzymes showed significant upregulation in the light. Other light-associated proteins, including bacterial cryptochrome and DNA photolyase, were also expressed at significantly higher levels in the light. Membrane transporters for Na(+)/phosphate and Na(+)/alanine symporters, and the Na(+)-translocating NADH-quinone oxidoreductase (NQR) linked electron transport chain, were also significantly upregulated in the light. Culture experiments using a specific inhibitor of Na(+)-translocating NQR indicated that sodium pumping via NQR is a critical metabolic process in the light-stimulated growth of MED134. In total, the results suggested the importance of both the PR-enabled, light-driven proton gradient, as well as the generation of a Na(+) ion gradient, as essential components for light-enhanced growth in these flavobacteria. PMID:21472017

  17. Ancillary Studies

    Cancer.gov

    Skip to Main Content Home | Data | Statistics | Tools | Collaborations | Work with Us | Publications | About | Links Ongoing Collaborations CISNET ACS FAVOR Comprehensive Cancer Centers Ancillary Studies Ancillary Studies Year

  18. 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.

  19. 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.

  20. 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)

  1. 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)

  2. 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

  3. 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

  4. 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…

  5. Quadrupole and magnetic mechanisms of 209Bi spin-lattice relaxation in Bi4Ge3O12

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Khozeev, D. F.; Morozova, E. N.; Orlov, V. G.; Shlikov, M. P.; Kargin, Yu F.

    2002-04-01

    The nuclear spin-lattice relaxation in the Bi4Ge3O12 single crystal was studied by the 209Bi NQR spin-echo technique. The recovery curves were measured for all 209Bi NQR transitions of nuclear spin I = 9/2 in a large temperature range 10-230 K. The experimental relaxation curves were described in terms of the single effective spin-lattice relaxation time T1*. The temperature dependence of 1/T1* was close to a Tn-law with n = 2.4-2.7. A theoretical treatment was given for the nuclear spin-lattice relaxation in the multi-level system for the case of a single-axial crystalline electric field. Both quadrupole and magnetic mechanisms of relaxation were taken into account. In separating the quadrupole and magnetic contributions, an idea of Rega (Rega T 1991 J. Phys.: Condens. Matter 3 1871) was used. To extract the temperature dependences of the parameters W1, W2 and WM the fitting procedure for calculated and experimental relaxation times was used. High-accuracy measurements of the recovery curves enable us to conclude that the magnetic mechanism contributes noticeably to the spin-lattice relaxation in Bi4Ge3O12 at T?50 K.

  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, Laous; Aissani, Sarra; March, Jean-Franois; 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. 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

  8. Study Carrels

    ERIC Educational Resources Information Center

    Training, 1977

    1977-01-01

    Information on various study carrels to provide individualized learning space for training use is presented. It is noted that carrels may be standard models or customized, and most are wired for audiovisual equipment. A list of study carrel suppliers and manufacturers is included. (MF)

  9. American Studies.

    ERIC Educational Resources Information Center

    Central Point School District 6, OR.

    Offering a program for uniting English with social studies, this curriculum guide for 11th grade American studies helps students develop into responsible, informed, capable citizens. The integrated approach of the social sciences, humanities, history, literature, writing, art, music, speech, and fields related to science and technology emphasizes

  10. 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

  11. 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...

  12. 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…

  13. 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

  14. 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…

  15. 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

  16. 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…

  17. 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...

  18. 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...

  19. 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.

  20. 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

  1. NMR studies of the internal electric field in a single crystal of the quasi-one-dimensional conductor Li0.9Mo6O17

    NASA Astrophysics Data System (ADS)

    Wu, Guoqing; Wu, Bing

    2015-03-01

    The quasi-one-dimensional (Q1D) conductor Li0.9Mo6O17 is of considerable interest because it has a highly conducting phase with properties likely associated with a Luttinger liquid, a poorly understood ``metal-insulator'' crossover at temperature TMI = 24 K, and a 3D superconducting phase that may involve triplet Cooper pairs at Tc = 2.2 K, while the mechanism for many of its properties has been a long mystery and it presents tremendous experimental challenges. We report the 7Li-NMR measurements of the internal electric field with an externally applied magnetic field B0 = 9 - 12 T, and we also show our theoretically calculated result of the electric field based on the structure of the crystal lattice. We find that the 7Li-NQR frequency (?Q) has a value of ~ 45 kHz and the electric field gradient (EFG) at the Li site due to the charges of the surrounding Mo conduction electrons has an axial symmetry with the principle axis (pz) to be along the lattice a-axis. There is no temperature or field dependence for the value of ?Q or EFG, indicating that the ``metal-insulator'' crossover has a magnetic origin, rather than the charge density wave (CDW) as one of the possible mechanisms previously thought in literature.

  2. 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

  3. 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

  4. Land mine detection by nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Hibbs, Andrew D.; Barrall, Geoffrey A.; Czipott, Peter V.; Lathrop, Daniel K.; Lee, Y. K.; Magnuson, Erik E.; Matthews, Robert; Vierkotter, Stephie A.

    1998-09-01

    Nuclear Quadrupole Resonance (NQR) combines the compound specific detection capability offered by chemical detection techniques with the spatial localization capability and convenience of an induction coil metal detector. In the 16 years since NQR was last applied to mine detection in the U.S., there has been considerable improvement in the basic techniques. This paper reviews the progress achieved under a recent initiative to detect landmines by NQR. Two basic technical developments are summarized: the design of a detection coil suitable for probing the ground for landmines buried at typical depths, and an increase in the NQR signal obtained from the explosive TNT. In addition, we report the sensitivity of an NQR detection system to detect the electromagnetic response of metal-cased landmines.

  5. Analysis of 27Al- and 93Nb-NMR spectra of PrNb2Al20 single crystal

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2016-02-01

    We report the results of 27Al- and 93Nb- nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements in PrNb2Al20 single crystals. The field angle dependence of the observed 93Nb-NMR lines for the single crystal at around 5 T and at 50 K is reproduced by a simulation using previously reported NQR parameters νQ,Nb ≈ 1.82 MHz and ηNb ≈ 0, while 27Al-NMR lines were not reproduce by the previously reported NQR parameters νQ,Al(3) ≈ 1.53 MHz and ηAl(3) ≈ 0.17. By reexamining and reconsidering the NMR and NQR lines for powder samples, we obtained a correct NQR parameters for Al(3) site to be νQ,Al(3),new ≈ 1 MHz and ηAl(3),new ≈ 0.4.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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.

  13. A DFT study of the 67Zn, 14N and 2H electric field gradient tensors in Zinc(II)-4-MeIm complexes and extrapolation to superoxide dismutase.

    PubMed

    Javadian, S; Araghi, R

    2009-01-01

    A computational investigation was carried out to characterize the (14)N and (2)H electric field gradient, EFG, in four protonated forms of 4-methyl imidazole (4-MeIm) and Histidine. In an attempt to establish metal binding effect in biological systems, we have considered the various forms of zinc (II) complexes of 4-MeIm. The computations were performed at the B3LYP and PW91P86 levels with 6-311++G(d,P) standard basis set. Calculated EFG tensors were used to determine (14)N and (2)H nuclear quadrupole coupling constant, chi and asymmetry parameter, eta. The results show that Zn(2+) has a strong effect on the NQR parameters (chi, eta) of proximal nitrogen in contrast with the remote nitrogen. In addition, EFG tensors at the Zn nuclear site were calculated for Zn-4-MeIm complexes and estimated the chi and eta values of (67)Zn. The influence of the bulk solvent was investigated at the B3LYP/6-311++G(d,p) level using the polarizable continuum model. Finally, we predicted (chi=1.95 MHz, eta=0.84) for proximal nitrogen, (chi=2.38 MHz, eta=0.07) for remote nitrogen and (chi=1.28 MHz, eta=0.22) for Zn in superoxide dismutase. PMID:19046908

  14. 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.

  15. 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…

  16. 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

  17. Modified steady-state free precession pulse sequences for the detection of pure nuclear quadrupole resonance.

    PubMed

    Rudakov, T N; Mikhaltsevitch, V T; Flexman, J H

    2004-01-01

    Modifications of the steady-state free precession multi-pulse technique for the effective detection of the nuclear quadrupole resonance (NQR) signals are proposed. These modifications are based on the use of composite pulses and enable the suppression of the coherent noise signals such as the magneto-acoustic and piezo-electric signals or the ringing signal from the NQR probe. Experimental results of applying the proposed technique to nitrogen-14 NQR in the sample of C6H12N4 are also presented and convincingly demonstrate its effectiveness. PMID:14698393

  18. Dipole Interaction in Triplet Superconductivity with Horizontal Line Nodes: Orientation of the Superconducting Order Parameter in Sr2RuO4

    NASA Astrophysics Data System (ADS)

    Hasegawa, Yasumasa

    2003-10-01

    Dipole interaction in triplet superconductivity is studied. If Cooper pairs are formed by electrons at r and r+(\\frac{a}{2},\\frac{a}{2},\\frac{c}{2}) in a body-centered tetragonal lattice (in this case line nodes run horizontally on a cylindrical Fermi surface), the dipole energy is low when the d-vector is perpendicular to the direction of the angular momentum of the Cooper pairs (l-vector). This result is in contrast with the dipole energies in the Anderson-Brinkman-Morel (ABM) state of superfluid 3He, where the d-vector is forced to be parallel or antiparallel to the l-vector by dipole interaction. The recent NQR experiment in Sr2RuO4 by Ishida et al. can be explained by this result.

  19. 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...

  20. Learn about Clinical Studies

    MedlinePLUS

    ... Studies Glossary of Common Site Terms Learn About Clinical Studies Contents What Is a Clinical Study? Clinical ... for Participation Questions to Ask What Is a Clinical Study? A clinical study involves research using human ...

  1. CASE STUDY CRITIQUE; UPPER CLINCH CASE STUDY

    EPA Science Inventory

    Case study critique: Upper Clinch case study (from Research on Methods for Integrating Ecological Economics and Ecological Risk Assessment: A Trade-off Weighted Index Approach to Integrating Economics and Ecological Risk Assessment). This critique answers the questions: 1) does ...

  2. Social Studies: Elementary Course of Study.

    ERIC Educational Resources Information Center

    Idaho State Dept. of Education, Boise.

    The purpose of this course of study guide is to delineate content requirements needed to satisfy K-9 proficiency expectations in social studies for the state of Idaho. Local school districts are given the task of producing instructional guides based on this course of study. For each grade, K-6, a course description is outlined and critical

  3. Paraguayan Education Study: A Pilot Study.

    ERIC Educational Resources Information Center

    Garcia, Patricia

    A qualitative pilot study, guided by an ecological framework, illustrates the complexities involved in studying the unique linguistic situation in Paraguay between Spanish and the indigenous language of Guarani, and its relationship with education. The pilot study interviewing eight kindergarten children. Seventy five children have been

  4. Design and testing of a low impedance transceiver circuit for nitrogen-14 nuclear quadrupole resonance.

    PubMed

    Sato-Akaba, Hideo

    2014-01-01

    A low impedance transceiver circuit consisting of a transmit-receive switch circuit, a class-D amplifier and a transimpedance amplifier (TIA) was newly designed and tested for a nitrogen-14 NQR. An NQR signal at 1.37MHz from imidazole was successfully observed with the dead time of ~85µs under the high Q transmission (Q~120) and reception (Q~140). The noise performance of the low impedance TIA with an NQR probe was comparable with a commercial low noise 50Ω amplifier (voltage input noise: 0.25 nV/Hz) which was also connected to the probe. The protection voltage for the pre-amplifier using the low impedance transceiver was ~10 times smaller than that for the pre-amplifier using a 50Ω conventional transceiver, which is suitable for NQR remote sensing applications. PMID:25293696

  5. Detection of RDX and TNT mine-like targets by nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Deas, Robert M.; Burch, Ian A.; Port, Daniel M.

    2002-08-01

    Nuclear quadrupole resonance (NQR) is being researched in order to confirm the presence of explosives as part of landmine sensor suites for the UK MOD hand held and vehicle mounted detection applied research programs. A low power NQR system has been developed as a non-contacting, but short range, detection method for explosives typically found in landmines. The results of stand-off detection of buried anti-personnel and anti-tank quantities of RDX and TNT by this system are presented and the differences in the detection of these explosives by NQR are discussed. Signal processing and radio frequency interference rejection methods to improve the performance of NQR explosive detection have been investigated.

  6. 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

  7. Social Studies Graded Course of Study.

    ERIC Educational Resources Information Center

    Stark County Dept. of Education, Louisville, OH.

    Basic social studies concepts and corresponding generalizations serve as the overall framework holding together the changing content of the curriculum in this guide. The K-6 organization of skills and concepts reflects an integrated social studies curriculum representing all the social sciences. The K-6 scope and sequence integrates five major

  8. Using Analogies to Study Social Studies Texts.

    ERIC Educational Resources Information Center

    Kuse, Loretta S.; Kuse, Hildegard R.

    1986-01-01

    A strategy to help senior high school social studies students overcome reading problems is suggested. Students are asked to use analogies to describe how they feel when they reach a difficult passage in their textbook. The students then use their own analogies to analyze ways to study the text. (RM)

  9. 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...

  10. ATBC Study - Contact Us

    Cancer.gov

    Skip to Main Content Home Contact Us Links Study Details Questionnaires & Forms Current Projects ATBC Study Bibliography Study Investigators & Collaborators Proposal Review & Collaboration Research Consortium Projects Contact Us If you are seeking general

  11. Shanghai Women's Health Study

    Cancer.gov

    The Shanghai Women's Health Study, a collaborative study by NCI, Vanderbilt University, and the Shanghai Cancer Institute, is a prospective cohort study of approximately 75,000 women, which aims to evaluate the causes of cancer among Chinese women.

  12. Learning to Study: Study Skills/Study Strategies. Book H.

    ERIC Educational Resources Information Center

    Mangrum, Charles T., II

    This workbook is one of a series that provides students with examples of location skills, organizational skills, interpretation skills, retention skills, test-taking skills, rate skills, and study strategies. Location skills include locating general reference sources and reviewing the card catalog system and the Dewey decimal system.…

  13. Nuclear quadrupole relaxation in chlorates

    NASA Astrophysics Data System (ADS)

    Kasprzak, J.; Pietrzak, J.

    Sodium, barium and silver chlorates have been subjected to NQR investigations, Measurements of the 35Cl pure quadrupole resonance frequency and relaxation times were carried out in the temperature range from 290 K to temperatures where the NQR signal vanishes. It was found, that temperature dependence of the T 1 indicates some activation processes. The hindered rotation of ClO 3 groups and the water diffusion are playing an essential role in the description of phenomena occuring in these crystals.

  14. Study Skills and Learning.

    ERIC Educational Resources Information Center

    Marton, Ference

    This report describes a study that investigated the relationship between the learning process and teaching at the university level. Specifically, the study sought to answer three questions: (1) What is a fruitful way of observing and describing knowledge? (2) How can study skill be observed and described? and (3) How can study skill be influenced?

  15. 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.

  16. A Canadian Social Studies.

    ERIC Educational Resources Information Center

    Parsons, Jim, Ed.; And Others

    The many ways social studies is taught and learned in elementary and secondary schools across Canada are examined. There are five parts. Part 1, "The Nature of the Social Studies," discusses what social studies is, describes the educational history of Canadian social studies, and examines the need and techniques for implementing a global

  17. Mixed-radiation-field dosimetry utilizing Nuclear Quadrupole Resonance. Final report

    SciTech Connect

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

    1992-12-31

    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.

  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. Electrodynamic tether system study: Extended study

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This document is the final report of a study performed by Ball Space Systems Division (BSSD) for the NASA Johnson Space Center under an extension to contract NAS9-17666. The tasks for the extended study were as follows: (1) Define an interface between the Electrodynamic Tether System (ETS) and the Space Station (SS); (2) Identify growth paths for the 100 kW ETS defined in the original study to a 200 kW level of performance; (3) Quantify orbit perturbations caused by cyclic day/night operations of a Plasma Motor/Generator (PMG) on the SS and explore methods of minimizing these effects; (4) Define the analyses, precursor technology, ground tests, and precursor demonstrations leading up to a demonstration mission for an electrodynamic tether system that would be capable of producing maneuvering thrust levels of 25 newtons; and (5) Propose a development schedule for the demonstration mission and preliminary cost estimates.

  20. 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.

  1. 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.…

  2. 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 ...

  3. 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)

  4. Home-Study Microlabs.

    ERIC Educational Resources Information Center

    Kennepohl, Dietmar

    1996-01-01

    Describes a pilot project for the home-study component of a first-year general chemistry course at Athabasca University that uses microscaled experiments. Presents four experiments and discusses home-study versus in-lab experience. (JRH)

  5. 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.

  6. 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.)

  7. Netherlands Cohort Study (NLCS)

    Cancer.gov

    The Netherlands Cohort Study (NLCS) started in 1986 and includes 120,852 men and women. The study population originates from 204 municipal population registries throughout The Netherlands, by gender-stratified random sampling.

  8. Boeing flywheel study

    SciTech Connect

    Rice, R.R.

    1983-12-01

    The major features of the history of the Boeing flywheel were studied. The analysis of the regenerative fuel cell was started as an outgrowth of the original Boeing study of the Space Operations Center, and was completed in November 1982 with the publication of the final report number D180-27160-1. The current flywheel effort attempts to study the integrated flywheel using the same ground rules that were used on the fuel cell study.

  9. 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.

  10. 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.

  11. Indian Studies Program.

    ERIC Educational Resources Information Center

    Peck, Cy, Sr.; And Others

    A product of the Indian Studies Curriculum Committee and the Indian Studies Staff, this manual on the Indians of Southeast Alaska constitutes a useable classroom tool designed for the cross-cultural program in the Juneau School District. Objectives of this Indian Studies Program are identified as: to increase knowledge, awareness, and positive…

  12. 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

  13. 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…

  14. Languages and International Studies

    ERIC Educational Resources Information Center

    Knoll, Samson B.

    1976-01-01

    International studies are defined as multicultural studies and students should be taught awareness and appreciation of diverse cultures as they relate to each other. Language study should be integrated into an interdisciplinary curriculum where languages receive new meaning and make new contributions. (CHK)

  15. 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)

  16. 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

  17. Effective Elementary Social Studies.

    ERIC Educational Resources Information Center

    Hoge, John Douglas

    This book advocates providing high-quality K-6 social studies instruction. The text provides practical information on how teachers can conduct high-quality social studies programs in their classrooms. The volume is divided into three parts. Part 1 offers an overview of the formal and informal social studies curriculum, its history, current status,

  18. Laboratory plasma studies

    NASA Astrophysics Data System (ADS)

    Fliflet, Arne

    1993-11-01

    The contents of the document are as follows: NIKE KrF Laser Support; Microwave and Millimeter Wave Experiments; Studies of Novel Accelerator Concepts and Free Electron Lasers; Studies for the Modified Betatron Accelerator (MBA); PHAROS 3 Studies; Electron Beam Diagnostics; Microwave Energy Deposition in the Upper Atmosphere; and Visualization Tools and Parallel Processing for Physics Applications.

  19. 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?

  20. Student Access Study.

    ERIC Educational Resources Information Center

    Wyoming Community Coll. Commission, Cheyenne.

    This study of Wyoming citizen access to community college education explored several factors related to college enrollments over the period 1990-1997. The study further examined projected student enrollment for 1998-2006. This study reports on the findings for: (1) Wyoming population trends and community college enrollments and projected…

  1. ATBC Study - Current Projects

    Cancer.gov

    Skip to Main Content Home Contact Us Links Study Details Questionnaires & Forms Current Projects ATBC Study Bibliography Study Investigators & Collaborators Proposal Review & Collaboration Research Consortium Projects Current Projects Prostate Lung Colorectal Pancreas Bladder Gastric Esophagus Renal Lymphomas/Leukemias Liver/biliary Head

  2. 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...

  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. 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

  5. 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…

  6. 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.

  7. 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-shirts, study 5, knitted ZQ Merino and modacrylic routine-wear T-shirts, with study 6 using only knitted polyester exercise shorts. No finishing treatment is used. Studies 4 and 5 use cross-over experimental designs, and all three studies were conducted aboard the ISS with six crew. Studies 4 and 6 were repeated on the ground with the same participants to learn if perception was affected microgravity. Study 7 is a longer-term, single-blind panel study of knitted routine-wear undershirts with at least 12 participants to assess tolerance to Merino by comparing it with a cotton/rayon blends, using a cross-over design, eliminating carryover effects with wash-out periods between shirts.

  8. 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 1640 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

  9. 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

  10. 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.

  11. New marine studies center

    NASA Astrophysics Data System (ADS)

    Temple University has established a Center for Marine Studies with faculty members from four of its colleges. The center will offer courses leading to a certificate in marine studies.Studies will focus on urbanization's impact on the marine environment and will focus on management and economics of waterfront utilization. In addition, faculty members will be constructing an artificial reef off Absecon Inlet to determine if increasing protective environments will permit increased sport fishing.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. College Environmental Study.

    ERIC Educational Resources Information Center

    Daniel, Gary Shelton

    Ways to study and evaluate different types of college environments are discussed, and sources of practical information about specific types of colleges are presented. Three main types of approaches used to measure college environments concern student behaviors (amount of time spent studying), student perceptions (the college is highly…

  18. 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.

  19. Poland's Jewish Studies.

    ERIC Educational Resources Information Center

    Bollag, Burton

    1995-01-01

    Scholarly interest in Jewish studies, discouraged during Communist rule, is experiencing a renaissance in Poland. However, because the Jewish community is largely gone from Poland, much of the research must be conducted outside the country. It is felt that earlier censorship has stimulated interest in Jewish studies. Polish scholars feel their…

  20. 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…

  1. Studies of Unwanted Babies

    ERIC Educational Resources Information Center

    Sigal, John J.

    2004-01-01

    Comments on the article by David, Dytrych, and Matejcek (see record 2003-03645-009) which showed the long-term negative psychological effects of unwantedness, up to 35 years after birth. The author states that despite their contention, this is not the only such long-term study. The authors briefly discuss other longitudinal studies of children

  2. 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

  3. 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…

  4. 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...

  5. Management Development Study.

    ERIC Educational Resources Information Center

    Department of Transportation, Washington, DC.

    This document reports on a management development study within the Department of Transportation (DOT). The aim of the study was to develop a systematic approach to management development for military and civilian personnel. A variety of methods was used to gather data including having DOT staff members gather the information to be passed on to the…

  6. 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…

  7. Methods of Studying Persons.

    ERIC Educational Resources Information Center

    Heinemann, Allen W.; Shontz, Franklin C.

    Conventional research strategies typically emphasize behavior-determining tendencies so strongly that the person as a whole is ignored. Research strategies for studying whole persons focus on symbolic structures, formulate specific questions in advance, study persons one at a time, use individualized measures, and regard participants as expert

  8. Social Studies Resource Guide.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany.

    This social studies guide is designed to serve as a companion document to the New York Framework and State Standards. The guide provides teachers with a wealth of information, strategies, learning experiences, sample assessments, research, and specific discipline materials to be used in the social studies curriculum development process within each

  9. 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:

  10. 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

  11. 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)

  12. Before 1776. Study Guide.

    ERIC Educational Resources Information Center

    Gruenbaum, Thelma

    Designed for use at the elementary level, this study guide accompanies a short history of the life and culture of the Massachusetts Bay Colony prior to the American Revolution (see related document, ED 108 997). The guide provides additional material as well as a series of study questions, suggestions for additional reading, and field trips within

  13. 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

  14. 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 ...

  15. 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,

  16. 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.

  17. Fall 1984 Retention Study.

    ERIC Educational Resources Information Center

    Peralta Community Coll. District, Oakland, CA. Office of Research, Planning and Development.

    A study was conducted of the retention patterns of students enrolled in the Peralta Community College District (PCCD) in fall 1984 using college reports on withdrawals and grade distributions. The study focused on successful retention (i.e., all students who received a passing grade) and on total retention (i.e., all students who received any

  18. Peace Studies Courses.

    ERIC Educational Resources Information Center

    Demeter, John; Marion, Kevin

    1974-01-01

    This publication provides a descriptive list of university peace studies programs and organizations that maintain resources in peace education. After a brief introduction in Chapter 1, Chapter 2 describes 34 undergraduate peace studies programs in universities in Canada, Sweden, United Kingdom, and the United States. Chapter 3 describes six

  19. Nuclear medicine case studies

    SciTech Connect

    Wagner, H.N. Jr.

    1986-01-01

    This text presents case studies in nuclear medicine which emphasize the diagnosis of the patient's problem rather than the technical performance of the procedure. The book is arranged by organ systems and each section begins with a description of the technique and findings in a normal study.

  20. Studies of Supervisory Behavior.

    ERIC Educational Resources Information Center

    Sistrunk, Walter E.

    A series of supervisory behavior studies that began at Mississippi State University in 1980 are summarized. The studies were instigated because of interest in effective supervision and dissatisfaction with an indepth literature search of supervision literature. The theories disclosed were fragmentary, contradictory, and impractical for use by

  1. 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…

  2. What Are Sleep Studies?

    MedlinePLUS

    ... Events Spokespeople Email Alerts E-Newsletters About NHLBI Organization NHLBI Director Budget, Planning, & Legislative Advisory Committees Contact Us FAQs Home » Health Information for the Public » Health Topics » Sleep Studies Explore Sleep Studies What Are... What To Expect ...

  3. Case Studies on Teaching.

    ERIC Educational Resources Information Center

    Kowalski, Theodore J.; And Others

    This book presents 36 case studies, based on data gathered from first-year teachers throughout the country, that provide direct involvement with some of the most common and important experiences new teachers face. By typing together practice and theory in the study of real problems, prospective teachers will be able to: (1) identify and use major

  4. Introduction to Childhood Studies

    ERIC Educational Resources Information Center

    Kehily, Mary Jane, Ed.

    2004-01-01

    Educationalists and social scientists are increasingly interested in childhood as a distinct social category, and Childhood Studies is now a recognized area of research and analysis. This book brings together the key themes of Childhood Studies in a broad and accessible introduction for students and practitioners working in this field.

  5. Women's Studies in India.

    ERIC Educational Resources Information Center

    Talwar, Rashmi

    1997-01-01

    Interest in women's issues in India has grown since 1975, when a report on the status of women raised concern about women's equality. Women's studies entered India's university curriculum only in 1986 but with little encouragement from the emerging women's movement. In India, women's studies looks to the West for research methods and ideas and is

  6. 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...

  7. 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

  8. 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…

  9. Case Study: Challenging Change.

    ERIC Educational Resources Information Center

    May, Steven K.

    2003-01-01

    Discusses a case study involving organizational change and its effect on employees. Presents three responses to the case study: "Paradox of Ordering Change: I Insist That We Work as a Team" (Paaige K. Turner); "Managing Change Is Managing Meaning" (Greg Hearn and Abraham Ninan); and "The Psychodynamics of an Organizational Change Initiative"

  10. 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.

  11. Facilitating Teacher Study Groups

    ERIC Educational Resources Information Center

    Walpole, Sharon; Beauchat, Katherine A.

    2008-01-01

    Although literacy coaching means many different things, all coaching initiatives have one common commitment: the goal of building teacher expertise. In the authors' work as coaches and with coaches, they have relied on teacher study groups as a main strategy for accomplishing this task. Their understanding of the potential for study groups has

  12. 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

  13. STUDIES IN MNEMONIC PROGRAMING.

    ERIC Educational Resources Information Center

    COHEN, JOZEF; AND OTHERS

    THIS STUDY CLASSIFIED MNEMONIC STRATEGIES, EXAMINED THEIR THEORETICAL CHARACTERISTICS, AND REPORTED EXPERIMENTS INVESTIGATING THE RELATIVE EFFECTIVENESS OF MNEMONICS IN PROGRAMED INSTRUCTIONAL MATERIALS. THE FIRST EXPERIMENT INVESTIGATED THE COMMON MNEMONICS USED BY STUDENTS IN STUDYING A MEDICAL TEXTBOOK. THE SECOND EXPERIMENT TESTED THE

  14. 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);…

  15. 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…

  16. 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...

  17. 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.

  18. Laser ignition studies

    SciTech Connect

    Fredin, L.; Hansen, G.P.; Margrave, J.L.; Behrens, R.G.

    1985-10-01

    The goal of this work is to study the details of laser induced ignition and combustion of high-temperature condensed-phase exothermic reactions. In this work high-speed photography (HSP) and real-time optical pyrometry have been combined to provide a diagnostic tool with a 1 ms temporal resolution for studying laser ignition and combustion wave propagation. Previous experiments have involved the use of HSP for studying combustion wave propagation (1) Real-time pyrometry studies of the ignition process have also been performed previously. The present paper describes how HSP has been expanded to include three-view split-frame photography to allow the ignition and combustion processes to be recorded and studied simultaneously. 2 refs., 3 figs.

  19. Teaching lesbian studies.

    PubMed

    Rothblum, Esther D

    2012-01-01

    Editorial Note: This essay on teaching lesbian studies is the first submission in a new feature in the Journal of Homosexuality, aimed at providing guidance to students and faculty who wish to teach courses in LGBT studies or to learn about basic concepts in the field such as minority stress, coming out models, heterosexism, etc. Esther D. Rothblum starts us out on this mission with her experiences teaching a course in lesbian studies. We encourage commentary on this piece and submissions about other experiences in teaching or introductions to basic concepts in sexuality and gender studies. This article describes teaching an upper-level undergraduate course on lesbian studies. It focuses on the types of students likely to enroll in this course, key aspects of gender identity and sexual orientation to be included, national and international issues to be discussed, and potential readings. PMID:22269051

  20. 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.

  1. 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.

  2. 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.

  3. Tokamak reactor studies

    SciTech Connect

    Baker, C.C.

    1981-01-01

    This paper presents an overview of tokamak reactor studies with particular attention to commercial reactor concepts developed within the last three years. Emphasis is placed on DT fueled reactors for electricity production. A brief history of tokamak reactor studies is presented. The STARFIRE, NUWMAK, and HFCTR studies are highlighted. Recent developments that have increased the commercial attractiveness of tokamak reactor designs are discussed. These developments include smaller plant sizes, higher first wall loadings, improved maintenance concepts, steady-state operation, non-divertor particle control, and improved reactor safety features.

  4. 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.

  5. [Case and studies].

    PubMed

    Schubert, András

    2015-11-15

    Case studies and case reports form an important and ever growing part of scientific and scholarly literature. The paper deals with the share and citation rate of these publication types on different fields of research. In general, evidence seems to support the opinion that an excessive number of such publications may negatively influence the impact factor of the journal. In the literature of scientometrics, case studies (at least the presence of the term "case study" in the titles of the papers) have a moderate share, but their citation rate is practically equal to that of other publication types. PMID:26548472

  6. Videofluoroscopic Swallowing Study (VFSS)

    MedlinePLUS

    ... Public / Speech, Language and Swallowing / Swallowing Videofluoroscopic Swallowing Study (VFSS) Do you have problems swallowing? You may ... to put yourself out there professionally on the Internet? Learn the cost and effort needed to best ...

  7. Genetic and Molecular Studies

    Cancer.gov

    DCEG strives to understand the interplay of molecular and genetic effects and radiation on cancer etiology. This type of work involves biological samples and high-quality dosimetry or other exposure assessment.Examples of such studies include:Childhood

  8. 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...

  9. 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.

  10. 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)

  11. Current Research Studies

    MedlinePLUS

    ... Be an Advocate CCFA Partners National Council of College Leaders CCFA Campus Connection Connect with Our Community IBD Help Center Explore CCFA Research Participate in Research Research Success Current Research Studies Microbiome Initiative Genetics Initiative Pediatric ...

  12. Diagnostic Errors Study Findings

    MedlinePLUS

    ... The study, partially funded by the Agency for Healthcare Research and Quality (AHRQ), estimates that approximately 12 million adults in the United States could experience an outpatient diagnostic error each year. ...

  13. 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.

  14. 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.

  15. 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.

  16. Kuwait oil spill studied

    NASA Astrophysics Data System (ADS)

    Bush, Susan

    1992-02-01

    More than a year after the Persian Gulf War, scientists are still trying to assess the environmental impact of the estimated 6-8 million barrels of oil that were dumped into the gulf and to understand the environmental processes that take place in such a disturbance. Many atmospheric studies were done in the months immediately following the war, but oceanographic studies have been slower in getting started.The National Oceanic and Atmospheric Administration is currently spearheading a major oceanographic study being undertaken in the Persian Gulf by the research vessel Mt. Mitchell. The ship left its home port of Norfolk, Va., in mid-January and arrived in Muscat, Oman, on February 16 to begin a 100-day oceanographic and environmental survey. The six-leg cruise will feature physical oceanography, near-shore, and marine life studies.

  17. 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.

  18. 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.

  19. Putting the Study Together

    ERIC Educational Resources Information Center

    Child & Youth Services, 2007

    2007-01-01

    This chapter outlines the research design including the nature of the research strategy, tools, respondents, and theoretical and methodological concerns in a child and youth care qualitative study. (Contains 3 figures and 9 notes.)

  20. 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)

  1. 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.

  2. 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.

  3. IRD dropout study

    NASA Technical Reports Server (NTRS)

    Yalowitz, Jeffrey S.; Schroer, Michael A.; Dickson, John E., Jr.

    1992-01-01

    This final report describes work performed by SRS Technologies for the NASA Marshall Space Flight Center under Contract NAS8-39077, entitled 'Integrated Receiver-Decoder Dropout Study'. The purpose of the study was to determine causes of signal fading effects on ultra-high-frequency (UHF) range safety transmissions to the Space Shuttle during flyout. Of particular interest were deep fades observed at the External Tank (ET) Integrated Receiver-Decoder (IRD) during the flyout interval between solid rocket booster separation and ET separation. Analytical and simulation methods were employed in this study to assess observations captured in flight telemetry data records. Conclusions based on the study are presented in this report, and recommendations are given for future experimental validation of the results.

  4. 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, ...

  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. 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.

  7. 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.

  8. Studying Sea Otters

    USGS Multimedia Gallery

    Sea otter researcher Michelle Staedler, of the Monterey Bay Aquarium, records sea otter behavior in her logbook as part of a study with the USGS and the University of California at Santa Cruz on sea otter behavior. ...

  9. 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)

  10. 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.

  11. 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.

  12. 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)

  13. 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.

  14. 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.

  15. 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 ...

  16. Manitoba Vision Screening Study.

    ERIC Educational Resources Information Center

    Rathgeber, Arthur J.

    1981-01-01

    The article describes a vision screening program in Manitoba to identify high-risk children. Organizational strategies, instrumentation, and results of a study of the effectiveness of the screening process with 732 children are detailed. (Author)

  17. 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

  18. 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)

  19. 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.

  20. Concrete containment aging study

    SciTech Connect

    Pachner, J.; Tai, T.M.; Naus, D.

    1994-04-01

    In 1989, IAEA initiated a pilot study on the management of aging of nuclear power plant components. The Phase I and II studies of concrete containment are discussed. With the data base, plant owners will be able to review and enhance their existing programs. IAEA will analyze data provided by participating plants and the report is scheduled to be released by late 1994 (final report release mid-1995).

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Model evaluation studies

    SciTech Connect

    Addis, R.P.; Bunker, S.S.; Dobosy, R.J.; Lange, R.; Porch, W.M.; Los Alamos National Lab., NM; National Oceanic and Atmospheric Administration, Oak Ridge, TN . Air Resources Lab. Atmospheric Turbulence and Diffusion Div.; Lawrence Livermore National Lab., CA; Los Alamos National Lab., NM )

    1989-01-01

    The Office of Health and Environmental Research (OHER) of the US Department of Energy (DOE) sponsors an ongoing series of atmospheric field studies whose main objectives are to increase fundamental knowledge of atmospheric transport and dispersion. This knowledge is used to develop technologies and methodologies required for both air quality assessments and real-time emergency response. These field studies have ranged from point releases of tracers in relatively simple terrain, to intensive field studies in extremely complex terrain. Scales have ranged from the mesoscale to the synoptic. This paper will give an overview of several DOE/OHER sponsored field experiments with particular emphasis on the role they have played in helping to improve and evaluate real-time atmospheric transport and dispersion models. The Mesoscale Atmospheric Transport Studies (MATS) and STable Atmospheric Boundary Layer Experiment (STABLE), conducted at Savannah River Site in South Carolina, have provided valuable data for model evaluation over gently rolling forested terrain. In contrast, the extensive series of Atmospheric Studies in COmplex Terrain (ASCOT) involve experiments in the extremely complex terrain of the Geysers area of northern California and Brush Creek in Colorado. Remote sensing has played a significant role in ASCOT in providing meteorological parameters for input into models. The vital role played by models in the initial design of these experiments will also be discussed. 41 refs., 3 figs., 1 tab.

  15. 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.

  16. 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.

  17. 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.

  18. Wright Field turboprop study

    SciTech Connect

    Lorenzetti, R.C.; Dull, P.P.

    1981-01-01

    The considered investigation was conducted as part of an effort to reduce aircraft fuel costs. Turboprops are very fuel efficient at speeds below Mach 0.6. One of the most promising approaches to reduce fuel consumption in the speed range from Mach 0.6 to 0.8 is related to an employment of the swept eight to ten blade propeller (propfan) being developed by NASA. All studies to date indicate that turboshaft engines with propfans might save 15% or more of the fuel used by a turbofan engine of comparable technology. Attention is given to a turboprop status review, contractor studies, the NASA propfan program, an in-house performance study, specific problems which have to be solved to make a twin-turboprop, 100-150 passenger transport a viable possibility for the early 1990s, and turboprop dilemmas.

  19. 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).

  20. 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 %22lessons learned%22 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 (~40 days) aging experiments with free standing and ceramic-supported Parylene C films highlighted %22lessons learned%22 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 (%22necking%22) for robust accelerated aging of Parylene C.

  1. 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.

  2. 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.

  3. Study of electroweak interactions

    NASA Astrophysics Data System (ADS)

    Abashian, A.; Gotow, K.; Piilonen, L.; Morgan, N.

    1992-10-01

    The experimental study of electroweak interactions at Virginia Tech is multifaceted and consists of three parts. The first consists of analysis of the final states of matter produced in electron-positron annihilations at center-of-mass energies (radical)s = 60 GeV at the TRISTAN collider in Japan (AMY). The second is a sensitive search for rare electroweak processes through a study of mu(+) yields e(+) gamma at the LAMPF facility at Los Alamos (MEGA). It also includes a precise measurement of the Michel (rho) parameter (RHO). The third activity is a R & D detector development and is a precursor to anticipated experiments at proposed B(sup o) meson factories in this country and/or abroad. The physics goals are the study of CP violation in the B(sup 0) system and the determination of the values for Kobayashi-Maskawa matrix.

  4. Black Hills hydrology study

    USGS Publications Warehouse

    Driscoll, D.G.

    1994-01-01

    The Black Hills area of western South Dakota is a valuable resource center. The area has attracted numerous residents and industries because of the availability of mineral, timber, agricultural, recreational, and water resources. The water resources of the area have been stressed locally by increasing population, periodic drought, and development of other resources. In response to residents' concerns about these stresses on the water resources, the Black Hills Hydrology Study was initiated in 1990 as a cooperative effort among the U.S. Geological Survey, the South Dakota Department of Environment and Natural Resources, and the West Dakota Water Development District. West Dakota represents the various local and county cooperators. This report describes the purpose, scope, approach, and status of the study and presents highlights from the first project data report produced for the study.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. ARIES tokamak reactor study

    SciTech Connect

    Steiner, D.; Embrechts, M.

    1990-07-01

    This is a status report on technical progress relative to the tasks identified for the fifth year of Grant No. FG02-85-ER52118. The ARIES tokamak reactor study is a multi-institutional effort to develop several visions of the tokamak as an attractive fusion reactor with enhanced economic, safety, and environmental features. The ARIES study is being coordinated by UCLA and involves a number of institutions, including RPI. The RPI group has been pursuing the following areas of research in the context of the ARIES-I design effort: MHD equilibrium and stability analyses; plasma-edge modeling and blanket materials issues. Progress in these areas is summarized herein.

  12. Advanced engine study program

    NASA Astrophysics Data System (ADS)

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

    1993-06-01

    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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Study of electroweak interactions

    NASA Astrophysics Data System (ADS)

    Abashian, A.

    This report is the final technical report for research conducted during the period 1 Feb. 1992 to 31 Jan. 1993. It covers three primary activities: the AMY experiment on the study of final states produced in e(+)e(-) collisions at the square root of s is approximately equal to 60 GeV, the MEGA/RHO experiment on the study of decay modes of the muon, and the R&D program on the development of resistive plate chambers for use at B factory electron colliders and possible SSC experiments.

  1. 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.

  2. 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.

  3. 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, Jaros?aw; 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 unusual characteristics such as large temperature effects on the intensity of some bands, thus presenting a challenge for theoretical band shape treatments. Our calculations clearly show that the present system is characterized by an asymmetric single well potential with no large amplitudes in the hydronium motion, which extends the existence of Zundel-type spectra beyond the established set of hydrogen bonds with large hydronic vibrational amplitudes. PMID:18225869

  4. Why Study Classical Languages?

    ERIC Educational Resources Information Center

    Lieberman, Samuel

    This speech emphasizes the significance of living literatures and living cultures which owe a direct debt to the Romans and the Greeks from whom they can trace their origins. After commenting on typical rejoinders to the question "Why study classical languages?" and poking fun at those who advance jaded, esoteric responses, the author dispels the

  5. 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.

  6. 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

  7. 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

  8. Study Blasts Leadership Preparation

    ERIC Educational Resources Information Center

    Archer, Jeff

    2005-01-01

    A far-reaching study offers a damning assessment of the programs that prepare most of the nation's principals and superintendents. Led by Arthur E. Levine, the president of Teachers College, Columbia University, the report says most university-based preparation programs for administrators range in quality from "inadequate to appalling." The

  9. 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.

  10. 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…

  11. 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...

  12. 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.

  13. 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

  14. 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,

  15. 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...

  16. 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 ...

  17. The Study of Education.

    ERIC Educational Resources Information Center

    Levit, Martin

    This paper examines several approaches to the study of the foundations of education and rejects all of them. Approaches are classified as "system-adaptive" or "system-reform" according to whether they examine existing educational systems and objectively analyze alternatives or whether they advocate specific new values or, indeed, freedom from all

  18. 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,…

  19. 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…

  20. Environmental Studies Model.

    ERIC Educational Resources Information Center

    George, David R.

    1986-01-01

    Presents a model of an environmental studies course that reflects a spaceship earth philosophy. Includes a rationale and a listing of concepts and processes for this action oriented program. Suggests several interdisciplinary experiences that emphasize problem-solving and decision-making skills. (ML)

  1. 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

  2. South America Map Study.

    ERIC Educational Resources Information Center

    Canipe, Stephen L.

    A simple "menu-driven" microcomputer program on map studies, designed to teach the geography of South America and certain economic facts about its countries, is presented. The program is written for an Apple II+ or Apple IIe computer; use on any other microcomputer will require substantial changes due to high resolution drawings and shape tables

  3. 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.

  4. 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."

  5. Cognitive Studies in Alcoholism.

    ERIC Educational Resources Information Center

    Wilson, G. Terence

    1987-01-01

    Commends cognitive studies for extending our understanding of alcohol use and abuse. The role of vicarious learning and efficacy and outcome expectations in the development, maintenance, and prevention of drinking, is stressed. Reinterpreted concepts of craving and loss of control as well as models of relapse and prevention treatment strategies,

  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. 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. 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...

  9. The Black Studies Debate.

    ERIC Educational Resources Information Center

    Gordon, Jacob U., Ed.; Rosser, James M., Ed.

    Beginning with the selection of Professor Newby, who attempts to reveal the role which historians, perhaps more specifically white historians, have played and continue to play in the perpetuation of racism in American culture, this anthology concludes with an analysis of the present status of Black Studies. W. Arthur Lewis' critical essay attempts

  10. 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

  11. 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

  12. 1992 NACUBO Endowment Study.

    ERIC Educational Resources Information Center

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

    This report presents the results of a 1992 study of the performance and management of college and university endowments. Part I offers succinct information on the data collection process, provides definitions, and explains the formula used in the analysis. Part II presents the report's exhibits in two sections. The first section describes: (1)

  13. 1991 NACUBO Endowment Study.

    ERIC Educational Resources Information Center

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

    This report presents the results of a 1991 study of the performance and management of endowments of colleges and universities. Part I offers information on the data collection and describes several definitions and formula used in the analysis. Part II presents the report's exhibits in two sections the first of which treats endowment

  14. Silicon sheet surface studies

    NASA Technical Reports Server (NTRS)

    Danyluk, S.

    1984-01-01

    Several activities were performed in the area of silicon sheet surface studies. An interferometry technique was developed for measuring residual stresses in short, thin silicon sheets. Simulation of abrasion of silicon by diamond and by scrating and indentation tests was carried out. The wear rate in silicon was correlated with a wear model.

  15. 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.

  16. 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.

  17. Elementary Course of Study.

    ERIC Educational Resources Information Center

    Nevada State Dept. of Education, Carson City.

    Designed to meet legislative requirements of the state of Nevada, the course of study for elementary school students presented in this guide establishes common goals for average students, which are to be adopted and followed by each school district. The course offers a foundation upon which local school districts can build curricula that are

  18. 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,

  19. RADON / MOISTURE STUDY

    EPA Science Inventory

    Limited field study in three basement houses in Mechanicsburg, Pa. Each house will have a radon mitigation installed and be monitored over the course of a year for moisture entry and control. Followed by a more extensive statistical analysis of the data.

  20. 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.

  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. HANOVER PARK TERTIARY STUDIES

    EPA Science Inventory

    During a one year study, four tertiary treatment units were tested and evaluated. Three of the units were deep-bed filters which were used to treat secondary plant effluent. The types of filters used were: (1) an upflow filter with a sand media, (2) a downflow gravity filter with...

  3. 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...

  4. 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…

  5. 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

  6. 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,…

  7. 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

  8. Geosynchronous Technology Infusion Studies

    NASA Technical Reports Server (NTRS)

    Hilliard, L.; Jenstrom, D.; Chesters, D.; Racette, P.

    1997-01-01

    NASA and NOAA are now sponsoring Advanced Geosynchronous Studies (AGeoS), technology work that will lead to the next generation of space sensors located in geosynchronous orbit. This report briefly describes the initial steps being taken to investigate the high priority geosynchronous measurement needs identified so far.

  9. 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)

  10. Fall 1982 Retention Study.

    ERIC Educational Resources Information Center

    Peralta Community Coll. District, Oakland, CA. Office of Research, Planning and Development.

    In fall 1982, a study was conducted in the Peralta Community College District (PCCD) using withdrawal and grade distribution data to analyze student retention patterns. Successful retention rates were based on the percentage of students who received a passing grade, while total retention rates were based on the percentage of students who received

  11. PEER Math Study Report.

    ERIC Educational Resources Information Center

    Giese, Elizabeth

    During the 1981-82 school year, the American Association of University Women (AAUW), collected mathematics data from school districts throughout the state of Michigan. AAUW is involved in a study of high technology and wanted to find out how education is preparing young people for the world of robotics, biotechnology, telecommunications, and the

  12. Studies on reactive flows

    SciTech Connect

    Sheu, Wenjenn.

    1989-01-01

    Theoretical, numerical and experimental studies are presented on the upstream interactions between premixed flamelets in turbulent combustions, the effect of centrifugal acceleration due to the rotation on Bunsen flames, extinction of counterflow diffusion flames in a counter-rotating finite jet, and nonplanar flame configurations in stagnation point flow. The processes during the upstream flame interactions are numerically investigated using two ozone decomposition planar flames propagating towards each other. The flame temperature and speed during the whole interaction process are also analyzed. One basic kind of rotational effects on the shape and stability of the premixed flames stabilized in Bunsen burner is theoretically and experimentally studied. The relation between the flame stabilization by the burner rim and rotation across the flame is examined. In addition the stable and unstable flame configuration are identified. In the study of the extinction characteristics of diffusion flames in opposed-jet flows with angular velocities which are equal in magnitude but opposite in directions, the extinction characteristics with vorticity in the flow were explored. The general configurations of premixed flame fronts in a stagnation point flow is pursued. Some flame shapes other than planar flames were verified. A simple mathematical model is given to provide the explicit expressions of flame fronts. The implications of these studies to the modeling of turbulent combustion are discussed.

  13. 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...

  14. 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...

  15. Why I Study Spanish.

    ERIC Educational Resources Information Center

    Uchmanowicz, Pauline

    English teachers together with multilingual and multidialect students can create new standards for language use and learning in the classroom. A teacher of writing and ethnic studies finds herself telling her students "I still have time to learn Spanish." Many to whom she speaks these words are native speakers of Spanish, struggling in classroom…

  16. 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,…

  17. Sidewalk Social Studies.

    ERIC Educational Resources Information Center

    Hatcher, Barbara; Olson, Mary

    1984-01-01

    Elementary teachers can increase public awareness of the value of social studies by having students conduct a sidewalk fair in a local shopping mall. One exemplary fair used the "Revolutionary Times" in American history theme; students read stories, showed filmstrips, and sang songs. Considerations for implementing a fair are discussed. (RM)

  18. 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…

  19. Ecological Field Studies

    ERIC Educational Resources Information Center

    Dobson, Christopher

    2008-01-01

    Field studies are an excellent way for students to learn ecological concepts and practice doing science. This article presents an approach for the secondary science classroom that permits students to ask and answer their own questions, a prerequisite for truly experiencing the process of science. Students explore a local natural area and, in

  20. 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...

  1. 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

  2. A Study of Sharing.

    ERIC Educational Resources Information Center

    Wolff, Joseph L.; Levy, Janet

    This paper is a report of a study which explores the relative contributions of norms, modeling, positive affect, and empathy to generalized reciprocity (prior help by one person leading to greater helpfulness by the recipient toward another person). Preschool children were randomly assigned to one of six groups and individually exposed to two…

  3. 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…

  4. 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,

  5. 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.

  6. 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...

  7. 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.

  8. School Staffing Trends Study.

    ERIC Educational Resources Information Center

    Oregon State Board of Education, Salem.

    This study examined the future staffing trends in Oregon's public schools, particularly with regard to teachers and counselors, within the context of the Oregon Educational Act for the 21st Century (HB 3565). Twenty-nine persons were interviewed, primarily superintendents, superintendent/principals, and assistant superintendents. Budget…

  9. Studying Philology Today

    ERIC Educational Resources Information Center

    Castanyer, Laura Borras

    2007-01-01

    As higher education is currently undergoing a radical transformation throughout Europe, philological studies face challenges from both inside and outside the discipline, some of which put into question the very existence of the field. This article investigates whether this crisis can also be seen as an opportunity for a profound rethinking of the

  10. 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

  11. 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 ...

  12. 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,

  13. 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.

  14. Dynamic EKG Study

    NASA Technical Reports Server (NTRS)

    Fleck, R. L.

    1970-01-01

    The use of the dynamic EKG study as a part of periodic health examination is considered to be a valuable complement to other forms of stress testing with its ability to detect abnormal heart responses to stress stimuli. It is believed that statistical correlations of dynamic EKG findings with physical examination results contribute greatly to the understanding of cardiac abnormalities.

  15. Australian Film Studies.

    ERIC Educational Resources Information Center

    Breen, Myles P.

    Although Australia had a vigorous film industry in the silent film era, it was stifled in the 1930s when United States and British interests bought up the Australian distribution channels and closed down the indigenous industry. However, the industry and film study have undergone a renaissance since the advent of the Labor government in 1972,

  16. 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…

  17. 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.

  18. Intermediate Mathematics Study Guide.

    ERIC Educational Resources Information Center

    Stanford Univ., CA. School Mathematics Study Group.

    This SMSG study guide is intended to provide teachers who use "Intermediate Mathematics," as a textbook with references to materials which will help them to gain a better understanding of the mathematics contained in the text. For each chapter of the text a brief resume of its content is followed by a list of annotated references which are…

  19. 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

  20. 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.

  1. The TIMSS Videotape Study.

    ERIC Educational Resources Information Center

    Stigler, James W.; Hiebert, James

    1998-01-01

    As part of the Third International Mathematics and Science Study (TIMSS), videotapes of classroom instruction were collected from 231 eighth-grade mathematics classrooms in Germany, the United States, and Japan. Findings suggest that written reports about teaching disseminated to teachers may have little effect on classroom practices. (SLD)

  2. 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.

  3. 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

  4. Oxygen boost pump study

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An oxygen boost pump is described which can be used to charge the high pressure oxygen tank in the extravehicular activity equipment from spacecraft supply. The only interface with the spacecraft is the +06 6.205 Pa supply line. The breadboard study results and oxygen tank survey are summarized and the results of the flight-type prototype design and analysis are presented.

  5. Albatross Satellite Tracking Study

    USGS Multimedia Gallery

    2007 Research crew for the short-tailed albatross satellite tracking study conducted on Torishima Island, Japan. Front row (left to right): Noboru Nakamura, Hayao Murakami, Paul Sievert, Yuki Watanabe, Fumio Sato. Back row: Miwa Tsuchiya, Robert Suryan. All of the Japanese researchers are from the Y...

  6. Study Mode Negotiation.

    ERIC Educational Resources Information Center

    Vasan, Mani Le; Sargunan, Rajeswary

    This paper outlines a model of study mode negotiation between clients and English Language Training providers that has been developed at the University of Malaya, specifically related to English language writing skills as taught to corporate clients. Negotiation is used to reach decisions concerning the goals and methodology of learning to ensure…

  7. Writing in Social Studies.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    Writing needs to be given adequate emphasis in the area of social studies. Teachers should attempt to be creative and to assign different kinds of writing in their classes. This paper discusses possible activities for students in a unit on the Middle East to illustrate diverse purposes in writing. An initial assignment could be to ask students to

  8. Conducting Student Retention Studies.

    ERIC Educational Resources Information Center

    Ewell, Peter T.

    Techniques for conducting student-attrition studies using the Student-Outcomes Information Service (SOIS) are outlined. General concepts to effectively guide an institutional research effort are discussed, with attention to better defining student attrition and a summary of results of recent research on the reasons why students withdraw from…

  9. 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.

  10. 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…

  11. Ecological Field Studies

    ERIC Educational Resources Information Center

    Dobson, Christopher

    2008-01-01

    Field studies are an excellent way for students to learn ecological concepts and practice doing science. This article presents an approach for the secondary science classroom that permits students to ask and answer their own questions, a prerequisite for truly experiencing the process of science. Students explore a local natural area and, in…

  12. ATTRITION RATE STUDY.

    ERIC Educational Resources Information Center

    HANSEN, M. DUANE; WENZEL, GUSTAVE G.

    INSTEAD OF FOCUSING ON STUDENT CHARACTERISTICS, AS DO MOST DROPOUT STUDIES, THIS ONE (1) CONSIDERS SPECIFIC INSTITUTIONAL CHARACTERISTICS OF GRADING PRACTICES, (2) ANALYZES THESE PRACTICES WITHIN A GIVEN TERM INSTEAD OF OVER SEVERAL YEARS, AND (3) BROADENS THE DEFINITION OF ATTRITION TO INCLUDE BOTH FAILURE AND WITHDRAWAL. IT ATTEMPTS TO IDENTIFY

  13. Regenerative fuel cell study

    NASA Technical Reports Server (NTRS)

    Wynveen, R. A.; Schubert, F. H.

    1972-01-01

    The completion of the study is reported for the regenerative fuel cell subsystem (RFCS) as an energy storage process for use aboard the space shuttle launched modular space station (MSS). The MSS mission requirements, and RFCS are discussed, and a comparison between RFCS and a nickel cadmium battery subsystem is presented. Development costs are also discussed.

  14. 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.

  15. 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,

  16. 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,

  17. 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…

  18. STRUCTURED CASE REVIEW STUDY.

    ERIC Educational Resources Information Center

    MILLER, LEONARD A.; MUTHARD, JOHN E.

    THIS STUDY EXAMINES A PROCEDURE FOR USING THE WRITTEN CASE RECORD AS A CRITERION FOR EVALUATING REHABILITATION COUNSELOR PERFORMANCE IN STATE "DVR" (STATE-FEDERAL GENERAL VOCATIONAL REHABILITATION PROGRAM) AGENCIES. THE RESEARCHERS OUTLINE CERTAIN OBJECTIVES (TECHNICAL, AGENCY SERVICES, AND STAFF DEVELOPMENT) AS DESIRABLE IN THE EVALUATION

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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

  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. Personnel Administration Department Study.

    ERIC Educational Resources Information Center

    Goren, Paul; Carriedo, Ruben

    This document reports on a study in the San Diego City Schools designed to (1) assess the level of satisfaction that school site staffs derived from the services of the Personnel Administration Department (PAD) and (2) make recommendations for improving PAD services to sites. The report, organized in five chapters, focuses on three major

  7. 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…

  8. 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…

  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 asked to identify the alert as quickly and as accurately as possible. Reaction time and accuracy were measured. Participants identified speech alerts significantly faster than tone alerts. The HERA study investigated the performance of participants in a flight-like environment. Participants were instructed to complete items on a task list and respond to C&W alerts as they occurred. Reaction time and accuracy were measured to determine if the benefits of speech alarms are still present in an applied setting.

  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 diagnostics of the anode closure phenomenon, and the use of arc jet thrusters for the deposition of c-BN, are being prepared.

  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. 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.

  13. 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.

  14. PET studies in epilepsy.

    PubMed

    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. (18)Fluoro-2-deoxyglucose ((18)F-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 (11)C-flumazenil (GABAA-cBDZ) and (18)F-MPPF (5-HT1A serotonin) and increased (11)C-cerfentanil (mu opiate) and (11)C-MeNTI (delta opiate) bindings in the area of seizure. (11)C-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 (11)C-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)O-H2O PET was reported to have a similar sensitivity to FDG-PET in detecting epileptic foci. PMID:26550535

  15. 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. 15O-H2O PET was reported to have a similar sensitivity to FDG-PET in detecting epileptic foci. PMID:26550535

  16. 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.

  17. [Bioavailability study of micronutrients].

    PubMed

    Pietrzik, K; Remer, T

    1989-06-01

    Bioavailability studies of micronutrients (vitamins, minerals) from different food stuffs, as well as from pharmaceutical preparations are of great importance for the calculation of nutrient intake and/or the evaluation of the therapeutic value. In practice, bioavailability studies are not generally performed on a standardized level. For this reason basic criterions are presented and discussed. Finally, the investigation of the bioavailability of folate is demonstrated by an example. The parameters investigated are: the maximal concentration (cmax), the time to reach this maximum (tmax), and especially the bioavailability ratio determined from the area under the curve (AUC) after administration of the folic acid containing test and reference preparation. The results indicate that 5-formyl-tetrahydrofolic acid given in the tested form has nearly the same bioavailability (ratio: 1.02) as folic acid (pteroylmonoglutamic acid) in aqueous solution. PMID:2669383

  18. 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.

  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. 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.

  1. Laser evaporation studies

    NASA Astrophysics Data System (ADS)

    Sankur, H.

    1986-10-01

    The use of a pulsed laser to evaporate dielectric materials for optical thin film deposition was investigated. The electrical properties of the laser induced plasma in the evaporant plume were studied. High flux (20A/sq cm) of high velocity (1 to 10 million) cm/s) ionic species were observed in the TEA-CO2 laser evaporation of many refractory oxides, chalcogenides and fluorides. Thin films of ZrO2 were deposited out of a plasma described above. These films were dense, oriented polycrystalline and had bulk refractive index values (2,15), low absorption (K about 0.001) and low particulate density for a range of laser fluence values. In the next and final phase of this project, thin film studies will be extended to a wider array of materials, with emphasis on obtaining high quality films with low particulate densities.

  2. 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.

  3. EUROv Super Beam Studies

    SciTech Connect

    Dracos, Marcos

    2011-10-06

    Neutrino Super Beams use conventional techniques to significantly increase the neutrino beam intensity compared to the present neutrino facilities. An essential part of these facilities is an intense proton driver producing a beam power higher than a MW. The protons hit a target able to accept the high proton beam intensity. The produced charged particles are focused by a system of magnetic horns towards the experiment detectors. The main challenge of these projects is to deal with the high beam intensity for many years. New high power neutrino facilities could be build at CERN profiting from an eventual construction of a high power proton driver. The European FP7 Design Study EUROv, among other neutrino beams, studies this Super Beam possibility. This paper will give the latest developments in this direction.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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 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 91 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.

  9. 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.

  10. 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.

  11. 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 identify any nuclear fuel cycle technology or option that may result in a significant beneficial impact to the issues as compared to the current U.S. approach of once-through use of nuclear fuel in LWRs or similar reactors followed by direct disposal of UNF. This approach was taken because incremental differences may be difficult to clearly identify and justify due to the large uncertainties that can be associated with the specific causes of the issues. Phase II of this Options Study continued the review of nuclear fuel cycle options that was initiated and documented during Phase I, concentrating on reviewing and summarizing the potential of integrated nuclear fuel cycles. However, based on the reviews of previous studies and available data, it was not always possible to clearly determine sufficiently large differences between the various fuel cycle and technology options for some of the issues or evaluation measures, for example, in cases where only incremental differences with respect to the issues might be achieved regardless of the fuel cycle option or technologies being considered, or where differences were insufficient to clearly rise above the uncertainties.

  12. Study of electroweak interactions

    NASA Astrophysics Data System (ADS)

    This document is a technical progress report for research conducted at Virginia Tech under DOE contract of 'Study of Electron-Positron Interactions' DE-AS05-80ER10713, Task B, during the past year. The report is divided into three main sections, dealing with the three primary activities of the group: the AMY experiment at TRISTAN (hardware upgrade, inclusive and isolated photon production, study of Bhabha scattering, electron substructure, and extra Z bosons, production of Lambda(sup 0) and Lambda(sup 0), and QED and search for pair production of massive photinos), the MEAGER/RHO experiment at LAMPF (planning and data acquisition for the decays mu(sup +) yields e+ gamma and mu+ yields e+nu(sub e)(anti nu)(sub mu)), and an r and d program on resistive plate chamber development at Virginia Tech.

  13. Millimeter wavelength propagation studies

    NASA Technical Reports Server (NTRS)

    Hodge, D. B.

    1974-01-01

    The investigations conducted for the Millimeter Wavelength Propagation Studies during the period December, 1966, to June 1974 are reported. These efforts included the preparation for the ATS-5 Millimeter Wavelength Propagation Experiment and the subsequent data acquisition and data analysis. The emphasis of the OSU participation in this experiment was placed on the determination of reliability improvement resulting from the use of space diversity on a millimeter wavelength earth-space communication link. Related measurements included the determination of the correlation between radiometric temperature and attenuation along the earth-space propagation path. Along with this experimental effort a theoretical model was developed for the prediction of attenuation statistics on single and spatially separated earth space propagation paths. A High Resolution Radar/Radiometer System and Low Resolution Radar System were developed and implemented for the study of intense rain cells in preparation for the ATS-6 Millimeter Wavelength Propagation Experiment.

  14. 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 the next two decades, provided policymakers stay the course with their policy goals. This project relied on a scenario-based analysis to study global biofuel markets. Scenarios were designed to evaluate the impact of different policy proposals and market conditions. World biofuel supply for selected scenarios is shown in Figure 1. The reference case total biofuel production increases from 12 billion gallons of ethanol equivalent in 2005 to 54 billion gallons in 2020 and 83 billion gallons in 2030. The scenarios analyzed show volumes ranging from 46 to 64 billion gallons in 2020, and from about 72 to about 100 billion gallons in 2030. The highest production worldwide occurs in the scenario with high feedstock availability combined with high oil prices and more rapid improvements in cellulosic biofuel conversion technologies. The lowest global production is found in the scenario with low feedstock availability, low oil prices and slower technology progress.

  15. 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.

  16. 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.

  17. 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)

  18. 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.

  19. QUADRENNIAL MCNP TIMING STUDY

    SciTech Connect

    E. C. SELCOW; B. D. LANSRUD

    2000-09-01

    The Los Alamos National Laboratory Monte Carlo N-Particle radiation transport code, MCNP, is widely used around the world for many radiation protection and shielding applications. As a well-known standard it is also an excellent vehicle for assessing the relative performance of scientific computing platforms. Every three-to-four years a new version of MCNP is released internationally by the Radiation Safety Information Computational Center (RSICC) in Oak Ridge, Tennessee. For each of the past few releases, we have also done a timing study to assess the progress of scientific computing platforms and software. These quadrennial timing studies are valuable to the radiation protection and shielding community because (a) they are performed by a recognized scientific team, not a computer vendor, (b) they use an internationally recognized code for radiation protection and shielding calculations, (c) they are eminently reproducible since the code and the test problems are internationally distributed. Further, if one has a computer platform, operating system, or compiler not presented in our results, its performance is directly comparable to the ones we report because it can use the same code, data, and test problems as we used. Our results, using a single processor per platform, indicate that hardware advances during the past three years have improved performance by less than a factor of two and software improvements have had a marginal effect on performance. The most significant impacts on performance have resulted from developments in multiprocessing and multitasking. The other most significant advance in the last three years has been the accelerated improvements in personal computers. In the last timing study, the tested personal computer was approximately a factor of four slower that the fastest machine tested, a DEC Alphastation 500. In the present study, the fastest PC tested was less than a factor of two slower than the fastest platform, which is a Compaq (previously DEC) Alpha XP1000.

  20. Singapore Chinese Health Study

    Cancer.gov

    The current research project continues support for a residential cohort of 63,257 middle-aged and older (45 to 74 years of age) Singapore Chinese men and women accrued between 1993 and 1998. At recruitment, each study participant was interviewed in person by a trained interviewer using a structured questionnaire that emphasized current diet assessed via a validated, 165-item food frequency questionnaire.