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1

Investigation of Structural Information for Boron - Solids and Aluminates via NMR and Nqr Studies.  

NASA Astrophysics Data System (ADS)

Nuclear Magnetic Resonance (NMR) has been prevailed in investigating local structures for a variety of materials: various oxide glasses, zeolites, superconductors, etc. Since glasses have short range ordered structures instead of long range ordered ones in crystals, NMR is usually more useful in determining the local structures for many glasses than any other detection methods do. Along with NMR, Nuclear Quadrupole Resonance (NQR) has become important recently for obtaining structural information from such glasses. The NQR studies prove in this thesis that they provide more accurate structural information than the NMR studies have done. This study presents boron and aluminum NMR, and NQR studies for some borate glasses and compounds, icosahedral boron-rich solids, some crystalline aluminosilicates. Various borates were employed to acquire structural information as well as to determine the quadrupole parameters (the quadrupole coupling constant Q_{cc } and the asymmetry parameter eta ) using NQR under a guidance of NMR or vice versa. By NQR a previously unknown boron site was observed for vitreous Li_2OcdotB _2O_3. The boron site had an intermediate Q_{cc } value in-between the reported value ranges of Q_{cc} for BO _3 and BO_4 sites, and was concluded to be a previously unknown BO _4 site. The NMR and NQR studies were performed on some icosachedral boron-rich solids: alpha -rhombohedral boron (B_{12}), beta-boron (B_{105 }) and boron carbide (B_{12 }C_3). Strong NQR responses were obtained from boron atoms in the C-B-C chains along with several other NQR responses from boron atoms in the icosahedral. These NQR results were consistent with the NMR studies by Silver and Bray, and those by Hynes and Alexander. Also, for the icosahedral boron-rich solids, the ^{11}B NMR studies revealed the possibility of chemical shifts due to two distinct boron sites in the icosahedra. A very interesting phenomenon was found from an isotopic change of boron nuclei (substitution of ^{10}B for ^{11}B) in boron carbide: in ^{11}B high field (7.05 Tesla) NMR spectra, two distinct peaks separated by some chemical shifts for unenriched boron carbide (B _{12}C_3) became a single peak for ^{10} B enriched boron carbide (90.61 at.% of ^{10}B). Three different forms of crystalline aluminosilicate (Al_2SiO_5) were studied by NQR. The NQR study yielded more accurate values of the quadrupole parameters for ^ {27}Al than the previous NMR single crystal study did.

Lee, Donghoon

2

27Al-NQR\\/NMR Study of Kondo Semiconductor CeFe2Al10  

Microsoft Academic Search

27Al-NQR\\/NMR measurements have been performed on CeFe2Al10 in relevance to the novel phase below T0=27 K of isostructural CeRu2Al10. NQR peaks are assigned to five crystallographically inequivalent Al sites. No splitting of the NQR spectra down to 1.5 K confirms the lack of phase transition in this compound. The gaplike decrease in the spin-lattice relaxation rate 1\\/T1 above about 20

Yukihiro Kawamura; Shingo Edamoto; Tomoaki Takesaka; Takashi Nishioka; Harukazu Kato; Masahiro Matsumura; Yo Tokunaga; Shinsaku Kambe; Hiroshi Yasuoka

2010-01-01

3

First-principles study of (75)As NQR in arsenic-chalcogenide compounds.  

PubMed

We present a theoretical study of the nuclear quadrupole interaction, ?(Q), of (75)As in crystalline and amorphous materials containing sulfur and selenium, and compare them with experiment. We studied a combination of hydrogen-terminated molecular clusters and periodic cells at various levels of quantum chemical theory. The results show clearly that the standard density functional theory (DFT) approximations, LDA and GGA, underestimate the nuclear quadrupole (NQR) interaction systematically, while Hartree-Fock theory overestimates it to an even greater degree. However, various levels of configuration interaction and the B3LYP hybrid exchange-correlation functional, which includes some exact exchange, give very good quantitative agreement for As bonded only to the chalcogen species. As-As bonds require highly converged basis sets. We have performed a systematic study of the effect of local distortions around an arsenic atom on ?(Q) and ?. Using a simple, semiclassical model, we have combined our total energy results with our NQR calculations to predict ?(Q) lineshapes for bond angle and bond length distortions. Our predictions for lineshape, including first and second moments, are in excellent agreement with the results of Su et al for a-As(2)S(3), a-As(2)Se(3) and a-AsSe. We offer new insight into the distortions that led to this inhomogeneous broadening. Our results show clearly that, for trivalent arsenic atoms with zero or one arsenic nearest neighbor, symmetric bond stretching is the predominant contributor to the ?(Q) linewidth. However, in the presence of two arsenic nearest neighbors, distortions of the As-As-As apex angle dominates and, in fact, leads to a much larger second moment, in agreement with experiment. PMID:21406910

Edwards, Arthur H; Taylor, P C; Campbell, Kristy A; Pineda, Andrew C

2011-02-01

4

First-principles study of 75As NQR in arsenic-chalcogenide compounds  

NASA Astrophysics Data System (ADS)

We present a theoretical study of the nuclear quadrupole interaction, ?Q, of 75As in crystalline and amorphous materials containing sulfur and selenium, and compare them with experiment. We studied a combination of hydrogen-terminated molecular clusters and periodic cells at various levels of quantum chemical theory. The results show clearly that the standard density functional theory (DFT) approximations, LDA and GGA, underestimate the nuclear quadrupole (NQR) interaction systematically, while Hartree-Fock theory overestimates it to an even greater degree. However, various levels of configuration interaction and the B3LYP hybrid exchange-correlation functional, which includes some exact exchange, give very good quantitative agreement for As bonded only to the chalcogen species. As-As bonds require highly converged basis sets. We have performed a systematic study of the effect of local distortions around an arsenic atom on ?Q and ?. Using a simple, semiclassical model, we have combined our total energy results with our NQR calculations to predict ?Q lineshapes for bond angle and bond length distortions. Our predictions for lineshape, including first and second moments, are in excellent agreement with the results of Su et al for a-As2S3, a-As2Se3 and a-AsSe. We offer new insight into the distortions that led to this inhomogeneous broadening. Our results show clearly that, for trivalent arsenic atoms with zero or one arsenic nearest neighbor, symmetric bond stretching is the predominant contributor to the ?Q linewidth. However, in the presence of two arsenic nearest neighbors, distortions of the As-As-As apex angle dominates and, in fact, leads to a much larger second moment, in agreement with experiment.

Edwards, Arthur H.; Taylor, P. C.; Campbell, Kristy A.; Pineda, Andrew C.

2011-02-01

5

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

PubMed

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 ?iso((93)Nb) values are in the range from 2400 to 3000ppm. 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 ?33) 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 (?11) 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

Peri?, Berislav; Gautier, Régis; Pickard, Chris J; Bosio?i?, Marko; Grbi?, Mihael S; Požek, Miroslav

2014-01-01

6

NQR investigation and characterization of cocrystals and crystal polymorphs  

NASA Astrophysics Data System (ADS)

The application of 14N NQR to the study of cocrystals and crystal polymorphs is reviewed. In ferroelectric and antiferroelectric organic cocrystals 14N NQR is used to determine proton position in an N-H...O hydrogen bond and proton displacement below TC. In cocrystal isonicitinamide - oxalic acid (2:1) 14N NQR is used to distinguish between two polymorphs and to determine the type of the hydrogen bond (N-...H-O). The difference in the 14N NQR spectra of cocrystal formers and cocrystal is investigated in case of carbamazepine, saccharin and carbamazepine - saccharin (1:1). The experimental resolution allows an unambiguous distinction between the 14N NQR spectrum of the cocrystal and the 14N NQR spectra of the cocrystal formers. The possibility of application of NQR and double resonance for the determination of the inhomogeneity of the sample and for the study of the life time of an unstable polymorph is discussed.

Seliger, Janez; Žagar, Veselko; Asaji, Tetsuo

2013-05-01

7

27Al-NQR Study on Novel Phase Transition in CeOs2Al10  

NASA Astrophysics Data System (ADS)

We have performed 27Al-NQR measurements in CeOs2Al10 which exhibits a novel phase transition at T0=29 K The NQR parameters determined for all the Al sites in ambient pressure were compared with those in CeRu2Al10 with T0=27 K and CeFe2Al10 with no phase transition. The distinct NQR splitting just below T0=32.5 K under pressure 0.66 GPa ensures an enhancement of T0 and a homogeneous transition. Despite the increase of T0, the nuclear spin-lattice relaxation rate 1/Tl is suppressed over whole range of temperature than in ambient pressure. The characteristic features of no critical slowing down at T0 and of the remarkable decrease of 1/T1T starting at T > T0 become prominent under pressure, suggesting an approach to Kondo semiconductor in a valence fluctuation regime.

Matsumura, M.; Inagaki, T.; Kato, H.; Nishioka, T.; Tanida, H.; Sera, M.

2012-12-01

8

Unconventional Pairing States in Heavy-Fermion Superconductors Studied by the NQR/NMR Experiments  

NASA Astrophysics Data System (ADS)

We review the studies on the unconventional superconducting pairing states and their relevance with magnetism in the f-electron derived heavy-fermion (HF) systems by means of nuclear-magnetic-resonance (NMR) and nuclear-quadrupole-resonance (NQR). These studies have unraveled a rich variety of the phenomena in the ground state of HF systems. In this article, we address an intimate relationship between the onset of strong-coupling superconductivity (SC) and critical magnetic fluctuations emerging in the vicinity of quantum critical point (QCP). Furthermore, we focus on the novel phase diagram of the HF antiferromagnet CeRhIn5 under pressure which is characterized by the tetracritical point separating the pure antiferromagnetism (AFM) phase, the AFM+SC uniformly coexisting phase, and the paramagnetic SC phase. A comparison is also presented on the AFM+SC uniformly coexisting phase in high-temperature superconductors as the function of carrier doping. As a consequence, we raise a question; Do we need a bosonic glue to pair electrons in these superconductors? Finally, we address a possible origin of the novel SC in the itinerant ferromagnet UGe2, which is mediated by ferromagnetic spin-density fluctuations relevant with the first-order transition inside the ferromagnetic states.

Kitaoka, Yoshio; Mukuda, Hidekazu; Yashima, Mitsuharu; Harada, Atsushi

2007-05-01

9

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)

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.

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

2006-06-01

10

35Cl-NQR and DFT study of electronic structure of amlodipine and felodipine vascular-selective drugs from the dihydropyridine Ca ++ antagonists group  

NASA Astrophysics Data System (ADS)

Amlodipine (AM) and felodipine (FL) have been studied in solid state by the nuclear quadrupole resonance (NQR) and density functional theory (DFT). The results have shown that NQR data do not permit a differentiation between R and S enantiomers, which is a consequence of the symmetry of the 4-aryl ring, whereas they permit a differentiation between free bases and salts. The HOMO-LUMO gap is smaller for AM than for FL, which suggests smaller energy of excitation for AM. The absolute hardness, chemical potential and electrophilicity of both AM enantiomers are lower than the corresponding values for FL enantiomers, suggesting that AM should be more reactive than FL in unimolecular reactions.

Latosi?ska, J. N.; Latosi?ska, M.; Kasprzak, J.

2008-09-01

11

27Al-NQR/NMR Study of Kondo Semiconductor CeFe2Al10  

NASA Astrophysics Data System (ADS)

27Al-NQR/NMR measurements have been performed on CeFe2Al10 in relevance to the novel phase below T0=27 K of isostructural CeRu2Al10. NQR peaks are assigned to five crystallographically inequivalent Al sites. No splitting of the NQR spectra down to 1.5 K confirms the lack of phase transition in this compound. The gaplike decrease in the spin-lattice relaxation rate 1/T1 above about 20 K, following the Korringa law (T1T = const.) below 20 K, indicates a pseudogap opening near the Fermi level. The gap magnitude of 70 K with a mid-gap state of 42% is estimated based on a rectangular density of states. The gap magnitude is much larger than the gap of 15 K evaluated previously from the electrical resistivity, which suggests CeFe2Al10 to be a Kondo semiconductor with a Kondo temperature much higher than 300 K.

Kawamura, Yukihiro; Edamoto, Shingo; Takesaka, Tomoaki; Nishioka, Takashi; Kato, Harukazu; Matsumura, Masahiro; Tokunaga, Yo; Kambe, Shinsaku; Yasuoka, Hiroshi

2010-10-01

12

Conformational isomerism of methyl dichloroacetate. An infrared, Raman and 35Cl NQR study  

NASA Astrophysics Data System (ADS)

The IR and Raman spectra of methyl dichloroacetate (M-DCA) have been recorded on the liquid, glassy and crystalline states. The vibrational assignment for M-DCA is proposed on the basis of the spectral comparisons between CCl nH 3? n COOCH 3 and CCl nH 5? n CONHCH 5 ( n = 0-3) in the solid state. The observed spectral data indicate that M-DCA exists as a conformational equilibrium in the liquid and in the glassy state and that the conformation in the crystalline state is entirely different from those in the liquid and glassy states. The 35Cl NQR spectrum suggests that the conformation of M-DCA in the crystalline state is the cis form in which one of the two chlorine atoms is located in the cis position with respect to the carbonyl group. Examination of vibrational spectra also leads to the same conclusion.

Mido, Yoshiyuki; Hashimoto, Masao

1985-10-01

13

Cooperative Phenomenon of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

Microsoft Academic Search

We report on a cooperative phenomenon of ferromagnetism and unconventional superconductivity (SC) in UGe2 through the measurements of 73Ge nuclear-quadrupole-resonance (NQR) under pressure (P). The NQR spectra evidenced phase separation into ferromagnetic and paramagnetic phases in the vicinity of Pc˜ 1.5 GPa, pointing to a first-order transition. The measurements of nuclear-spin-lattice-relaxation-rate 1\\/T1 revealed that SC emerges under the background of

Atsushi Harada; Shinji Kawasaki; Hisashi Kotegawa; Yoshio Kitaoka; Yoshinori Haga; Etsuji Yamamoto; Yoshichika Onuki; K. M. Itoh; Eugene Haller; Hisatomo Harima

2005-01-01

14

Novel phase diagram of superconductivity and ferromagnetism in UGe2: a 73Ge-NQR study under high pressure  

Microsoft Academic Search

We report on the pressure-induced novel phases of ferromagnetism (FM) and superconductivity (SC) in the itinerant ferromagnet UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum points to a first-order transition from strongly to weakly polarized ferromagnetic phases (SP and WP) around a critical pressure of P_{\\\\mathrm {c}}^*\\\\sim 1.2 GPa. Furthermore, it shows the phase

Y. Kitaoka; H. Kotegawa; A. Harada; S. Kawasaki; Y. Kawasaki; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima

2005-01-01

15

Evidence for the microscopic coexistence of superconductivity and ferromagnetism in UGe2:Ge-NMR\\/NQR study  

Microsoft Academic Search

We report on the pressure-induced novel phases of ferromagnetism and superconductivity (SC) in the itinerant ferromagnet UGe2 via the 73Ge-NQR measurements under pressure (P). The NQR spectrum has revealed that the ferromagnetic phases are separated into weakly and strongly polarized phases around a critical value of Pc*˜1.2GPa, pointing to a first-order transition around Pc*. Here we present further evidence for

A. Harada; H. Kotegawa; Y. Kawasaki; G.-Q. Zheng; Y. Kitaoka; E. Yamamoto; Y. Haga; Y. Onuki; K. Itoh; E. E. Haller

2005-01-01

16

Evidence for Uniform Coexistence of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

Microsoft Academic Search

We report on the itinerant ferromagnetic superconductor UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum signals a first-order transition from the low-temperature (T) and low-P ferromagnetic phase (FM2) to high-T and high-P one (FM1) around a critical pressure of Px ˜ 1.2 GPa. The superconductivity exhibiting a maximum value of Tsc=0.7 K at Px

H. Kotegawa; A. Harada; S. Kawasaki; Y. Kawasaki; Y. Kitaoka; Y. Haga; E. Yamamoto; Y. Onuki; K. M. Itoh; E. E. Haller; H. Harima

2005-01-01

17

Cooperative Phenomenon of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

NASA Astrophysics Data System (ADS)

We report on a cooperative phenomenon of ferromagnetism and unconventional superconductivity (SC) in UGe2 through the measurements of 73Ge nuclear-quadrupole-resonance (NQR) under pressure (P). The NQR spectra evidenced phase separation into ferromagnetic and paramagnetic phases in the vicinity of Pc˜ 1.5 GPa, pointing to a first-order transition. The measurements of nuclear-spin-lattice-relaxation-rate 1/T1 revealed that SC emerges under the background of ferromagnetism, but not of the paramagnetic phase.

Harada, A.; Kawasaki, S.; Kotegawa, H.; Kitaoka, Y.; Haga, Y.; Yamamoto, E.; ?nuki, Y.; Itoh, K. M.; Haller, E. E.; Harima, H.

2005-10-01

18

Stability and molecular dynamics of chloroxylenol (API of antiseptics and drugs) in solid state studied by 35Cl-NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

Thermal stability of 4-chloro-3,5-dimethyl-phenol (chloroxylenol) in solid state has been studied by 35Cl-NQR spectroscopy. Two NQR resonance lines at the frequencies 34.348 and 34.415 MHz at 77 K have been assigned to chlorine atoms from two crystallographically inequivalent molecules on the basis of the B3LYP/6-311++G ?? results. The temperature dependence of the resonance frequency and full width at half maximum suggest the occurrence of small-angle torsional oscillations of the mean activation energy of 3.83 kJ/mol and rotation of both methyl groups around their symmetry axis C3 with the activation energies 12.49 and 11.27 kJ/mol for CH 3 in molecule A and B, respectively. B3LYP/6-311++G ?? method reproduced very well the activation energies of both motions.

Latosi?ska, J. N.; Tomczak, M. A.; Kasprzak, J.

2009-02-01

19

Critical behavior study of antiferromagnetism in isostructural La2CuO4+delta and La2NiO4+delta  

Microsoft Academic Search

Neutron diffraction [1] and nuclear quadruple resonance [2] experiments coupled with theory calculations provide substantial evidence to support the widely-accepted belief that the two-dimensional Heisenberg model describes the antiferromagnetic interactions in La2CuO4 (S = .5ex1-.1em\\/ -.15em.25ex2 ) and La2NiO4 (S = 1). The heat capacity critical exponent alpha, which could provide further evidence, has never been studied in these two

Benjamin White; John Neumeier; A. Erb

2009-01-01

20

Copper Nqr and NMR Study of Metal-Substituted Yttrium BARIUM(2) COPPER(3) OXYGEN(7) and Yttrium BARIUM(2) COPPER(4) OXYGEN(8)  

NASA Astrophysics Data System (ADS)

Pulsed nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) have been used to investigate the effect of metal-substitution for copper in YBa_2Cu_3O_7 (YBCO123) and YBa_2Cu_4O_8 (YBCO124). Among many metal substitutions, Zn has an especially dramatic effect in suppressing the superconducting temperature T_{c}, and hence superconductivity. More interesting is that Zn and Fe have the same T_{c} suppression effect in YBCO124. This study focuses on the Zn substitutions in YBCO123 and Zn, Fe, and Co substitutions in YBCO124. In Zn doped YBCO123, Cu(2), plane site, NQR spectra and the frequency dependence of the spin-lattice relaxation rates have been measured over a temperature range from 77 K to 300 K to study the correlation of the suppression of the relaxation rate with the distance between the probe Cu nuclei and the impurity. It is found that the relaxation rate is insensitive to the variation of the NQR resonance frequency. However, by comparing the results of the Zn doped YBCO124 with those of YBCO123, it can be concluded that the suppression of the relaxation rate for both YBCO compounds in the normal state is caused by destruction of short-range antiferromagnetic correlation with substitution of nonmagnetic ion Zn on the Cu(2) sites. NQR and NMR measurements were carried out on both Cu(2), plane, and Cu(1), chain sites, for various concentrations of Zn, Fe, and Co dopants in YBCO124 over a temperature range from 77 K to 300 K. A strong correlation of the enhancement of Cu(2) spin lattice relaxation rate and suppression of superconductivity by impurities was found. The temperature dependence of the Cu(2) NMR linewidth exhibits a strong RKKY type exchange interaction below 225 K for Zn and Fe doped samples, which indicates the formation of the local magnetic moment. The enhancement of the relaxation rate is caused by the local magnetic moment Fe^ {+3} ion and the moments on Cu(2) neighbors when Zn^{+2} is substituted on Cu(2). This study gives us a clear picture of the spin pseudogap behavior in the high temperature superconductor cuprates. It also suggests that the magnetic moment on the CuO_2 plane may relate to the suppression of T_{c} in metal-substituted YBCO124.

Cheng, Show-Jye

21

Evidence for the microscopic coexistence of superconductivity and ferromagnetism in UGe2:73Ge-NMR/NQR study  

NASA Astrophysics Data System (ADS)

We report on the pressure-induced novel phases of ferromagnetism and superconductivity (SC) in the itinerant ferromagnet UGe2 via the 73Ge-NQR measurements under pressure ( P). The NQR spectrum has revealed that the ferromagnetic phases are separated into weakly and strongly polarized phases around a critical value of Pc*?1.2 GPa, pointing to a first-order transition around Pc*. Here we present further evidence for the phase separation into ferromagnetic and paramagnetic phases around a critical pressure Pc?1.6 GPa. The measurements of nuclear spin-lattice relaxation rate 1/T1 have probed that SC sets only in the ferromagnetic phase at Tsc?0.2 K, but it does not in the paramagnetic phase.

Harada, A.; Kotegawa, H.; Kawasaki, Y.; Zheng, G.-q.; Kitaoka, Y.; Yamamoto, E.; Haga, Y.; ?nuki, Y.; Itoh, K.; Haller, E. E.

2005-04-01

22

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)

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.

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

2008-02-01

23

Evidence for Uniform Coexistence of Ferromagnetism and Unconventional Superconductivity in UGe2: A 73Ge-NQR Study under Pressure  

NASA Astrophysics Data System (ADS)

We report on the itinerant ferromagnetic superconductor UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum signals a first-order transition from the low-temperature (T) and low-P ferromagnetic phase (FM2) to high-T and high-P one (FM1) around a critical pressure of Px ˜ 1.2 GPa. The superconductivity exhibiting a maximum value of Tsc=0.7 K at Px ˜ 1.2 GPa, was found to take place in connection with the P-induced first-order transition. The nuclear spin-lattice relaxation rate 1/T1 has probed the ferromagnetic transition, exhibiting a peak at the Curie temperature as well as a decrease without the coherence peak below~Tsc. These results reveal the uniformly coexistent phase of ferromagnetism and unconventional superconductivity with a line--node gap. We remark on an intimate interplay between the onset of superconductivity and the underlying electronic state for the ferromagnetic phases.

Kotegawa, H.; Harada, A.; Kawasaki, S.; Kawasaki, Y.; Kitaoka, Y.; Haga, Y.; Yamamoto, E.; ?nuki, Y.; Itoh, K. M.; Haller, E. E.; Harima, H.

2005-02-01

24

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

Microsoft Academic Search

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

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

2006-01-01

25

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)

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 = 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.

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

2013-12-01

26

Explosives detection by nuclear quadrupole resonance (NQR)  

NASA Astrophysics Data System (ADS)

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.

Garroway, Allen N.; Buess, M. L.; Yesinowski, J. P.; Miller, J. B.; Krauss, Ronald A.

1994-10-01

27

Pressure-induced unconventional superconductivity in the heavy-fermion antiferromagnet CeIn3 : An In115 -NQR study under pressure  

NASA Astrophysics Data System (ADS)

We report on pressure-induced unconventional superconductivity (SC) in the heavy-fermion (HF) antiferromagnet CeIn3 by means of nuclear-quadrupole-resonance (NQR) studies conducted under a high pressure. The temperature (T) and pressure (P) dependences of the In-NQR spectra have revealed a first-order quantum-phase transition (QPT) from antiferromagnetism (AFM) to paramagnetism (PM) at a critical pressure Pc=2.46GPa at which AFM disappears with a minimum value of TN(Pc)=1.2K . High-energy x-ray scattering measurements under P show a progressive decrease in the lattice density without any change in the crystal structure, whereas an increase in the NQR frequency (?Q) indicates an increase in the hybridization between 4f electrons and conduction electrons, which stabilizes the HF-PM state. This competition between the AFM phase where TN is reduced and the formation of the HF-PM phase triggers the first-order QPT at Pc=2.46GPa . Despite the lack of an AFM quantum critical point in the P-T phase diagram, we highlight the fact that unconventional SC occurs in both phases of AFM and PM. The measurements of the nuclear spin-lattice relaxation rate 1/T1 in the AFM phase have provided evidence for the uniformly coexisting AFM+SC phase. Remarkably, the significant increase in 1/T1 upon cooling in the AFM phase has revealed the development of low-lying magnetic excitations down to Tc in the AFM phase; it is indeed relevant to the onset of the uniformly coexisting AFM+SC phase. In the HF-PM phase where AFM fluctuations are not developed, 1/T1 decreases without the coherence peak just below Tc , followed by a power-law-like T dependence that indicates an unconventional SC with a line-node gap. Remarkably, Tc has a peak around Pc in the HF-PM phase as well as in the AFM phase. In other words, an SC dome exists with a maximum value of Tc=230mK around Pc , indicating that the origin of the pressure-induced HF SC in CeIn3 is not relevant to AFM spin fluctuations but to the emergence of the first-order QPT in CeIn3 . These phenomena observed in CeIn3 should be understood in terms of the first-order QPT because these new phases of matter are induced by applying P . When the AFM critical temperature is suppressed at the termination point of the first-order QPT, Pc=2.46GPa , the diverging AFM spin-density fluctuations emerge at the critical point from AFM to PM. The results with CeIn3 leading to a new type of quantum criticality deserve further theoretical investigations.

Kawasaki, S.; Yashima, M.; Kitaoka, Y.; Takeda, K.; Shimizu, K.; Oishi, Y.; Takata, M.; Kobayashi, T. C.; Harima, H.; Araki, S.; Shishido, H.; Settai, R.; ?nuki, Y.

2008-02-01

28

Conformations and intermolecular interactions pattern in solid chloroxylenol and triclosan (API of anti-infective agents and drugs). A (35) Cl NQR, (1) H-(14) ?N NQDR, X-ray and DFT/QTAIM study.  

PubMed

Two antibacterial and antifungal agents, chloroxylenol (4-chloro-3,5-dimethyl-phenol) and triclosan (5-chloro-2-(2',4'-dichlorophenoxy)-phenol), were studied experimentally in solid state with an X-ray, (35) Cl-nuclear quadrupole resonance (NQR) and (17) O-nuclear quadrupole double resonance (NQDR) spectroscopies and, theoretically, with the density functional theory/quantum theory of atoms in molecules (DFT/QTAIM). The crystallographic structure of triclosan, which crystallises in space group P3(1) with one molecule in the asymmetric unit [a?=?12.64100(10), b?=?12.64100(10), c = 6.71630(10) Å], was solved with an X-ray and refined to a final R-factor of 2.81% at room temperature. The NQR frequencies of (35) Cl and (17) O were detected with the help of the density functional theory (DFT) assigned to particular chlorine and oxygen sites in the molecules of both compounds. The NQR frequencies at (35) Cl sites in chloroxylenol and triclosan were found to be more differentiated than frequencies at the (17) O site. The former better describes the substituent withdrawing effects connected to ?-electron delocalization within the benzene rings and the influence of temperature; whereas, those at the (17) O site provide more information on O-H bond and intermolecular interactions pattern. The conformation adopted by diphenyl ether of triclosan in solid state was found to be typical of diphenyl ethers, but the opposite to those adopted when it was bound to different inhibitors. According to an X-ray study, temperature had no effect on the conformation of the diphenyl ring of triclosan, which was the same at 90?K and at room temperature (RT). The scattering of NQR frequencies reproduced by the DFT under assumption of the X-ray data at 90?K and RT is found to be a good indicator of the quality of resolution of the crystallographic structure. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22354770

Latosi?ska, J N; Latosi?ska, M; Tomczak, M A; Seliger, J; Zagar, V; Maurin, J K

2012-02-21

29

FPGA based pulsed NQR spectrometer  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

30

NMR and NQR parameters of the SiC-doped on the (4,4) armchair single-walled BPNT: a computational study.  

PubMed

The structural properties, NMR and NQR parameters in the pristine and silicon carbide (SiC) doped boron phosphide nanotubes (BPNTs) were calculated using DFT methods (BLYP, B3LYP/6-31G) in order to evaluate the influence of SiC-doped on the (4,4) armchair BPNTs. Nuclear magnetic resonance (NMR) parameters including isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (13)C, (29)Si, (11)B, and (31)P atoms and quadrupole coupling constant (C ( Q )), and asymmetry parameter (? ( Q )) at the sites of various (11)B nuclei were calculated in pristine and SiC- doped (4,4) armchair boron phosphide nanotubes models. The calculations indicated that doping of (11)B and (31)P atoms by C and Si atoms had a more significant influence on the calculated NMR and NQR parameters than did doping of the B and P atoms by Si and C atoms. In comparison with the pristine model, the SiC- doping in Si(P)C(B) model of the (4,4) armchair BPNTs reduces the energy gaps of the nanotubes and increases their electrical conductance. The NMR results showed that the B and P atoms which are directly bonded to the C atoms in the SiC-doped BPNTs have significant changes in the NMR parameters with respect to the B and P atoms which are directly bonded to the Si atoms in the SiC-doped BPNTs. The NQR results showed that in BPNTs, the B atoms at the edges of nanotubes play dominant roles in determining the electronic behaviors of BPNTs. Also, the NMR and NQR results detect that the Fig. 1b (Si(P)C(B)) model is a more reactive material than the pristine and the Fig. 1a (Si(B)C(p)) models of the (4,4) armchair BPNTs. PMID:21625895

Baei, Mohammad T; Sayyad-Alangi, S Zahra; Moradi, Ali Varasteh; Torabi, Parviz

2012-03-01

31

14N NQR in the tetrazole family  

NASA Astrophysics Data System (ADS)

14N NQR frequencies and spin-lattice relaxation times were measured in technologically important 5-aminotetrazole and 5-aminotetrazole monohydrate at different temperatures between 77 K and 300 K. Five NQR triplets ?+, ?- and ?0 were found for the five inequivalent nitrogen atoms in each compound between 0.7 MHz and 4 MHz. Carr-Purcell based multipulse sequences were used to accumulate quadrupole echo signals before the FFT analysis. Assignment of the frequencies to atomic positions was made and the results are analysed in relation to the molecular chemical bonds and possible H-bonds in the crystal structures. The new NQR frequencies are reasonably related to the previously published NQR spectrum of the third family member, 1H-tetrazole.

Pirnat, Janez; Lužnik, Janko; Jazbinšek, Vojko; Žagar, Veselko; Seliger, Janez; Klapötke, Thomas M.; Trontelj, Zvonko

2009-10-01

32

Supramolecular synthon pattern in solid clioquinol and cloxiquine (APIs of antibacterial, antifungal, antiaging and antituberculosis drugs) studied by ³?Cl NQR, ¹H-¹?O and ¹H-¹?N NQDR and DFT/QTAIM.  

PubMed

The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were studied experimentally in the solid state via ³?Cl NQR, ¹H-¹?O and ¹H-¹?N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O-H···N hydrogen bonds linking dimers and ?-? stacking interactions were described within the QTAIM (quantum theory of atoms in molecules) /DFT (density functional theory) formalism. Both proton donor and acceptor sites in O-H···N bonds were characterized using ¹H-¹?O and ¹H-¹?N NQDR spectroscopies and QTAIM. The possibility of the existence of O-H···H-O dihydrogen bonds was excluded. The weak intermolecular interactions in the crystals of clioquinol and cloxiquine were detected and examined. The results obtained in this work suggest that considerable differences in the NQR parameters for the planar and twisted supramolecular synthons permit differentiation between specific polymorphic forms, and indicate that the more planar supramolecular synthons are accompanied by a greater number of weaker hydrogen bonds linking them and stronger ?···? stacking interactions. PMID:21080020

Latosi?ska, Jolanta Natalia; Latosi?ska, Magdalena; Tomczak, Marzena Agnieszka; Seliger, Janez; Zagar, Veselko

2011-07-01

33

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

SciTech Connect

[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.

Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I. (Ames Laboratory, U.S. Department of Energy and Department of Physics Astronomy, Iowa State University, Ames, Iowa 50011 (United States))

1994-12-01

34

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

PubMed

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

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

2012-09-01

35

35Cl NQR of an organic ferroelectric phenazine chloranilic acid co-crystal  

NASA Astrophysics Data System (ADS)

A ferroelectric transition of phenazine (Phz) chloranilic acid (H 2ca) co-crystal was studied by 35Cl nuclear quadrupole resonance (NQR). The single NQR line observed at 36.689 MHz at 295 K, split into a doublet below the ferroelectric transition temperature Tc=253 K in accord with the inversion-symmetry breaking at the H 2ca molecular center in the crystal. The continuous variation of the splitting-width through Tc suggests a second-order nature of this phase transition. The NQR frequency is consistent with the crystal structure in which the two acid hydrogen atoms of H 2ca remain as attached to the quinone molecules. The spin-lattice relaxation time T1 showed a decrease with decreasing temperature in the ferroelectric phase. This suggests the existence of a fast motion of nearby atomic group, which is a cause of electric field gradient fluctuation.

Asaji, Tetsuo; Gotoh, Kazuma; Watanabe, Jun

2006-06-01

36

Roles of the sodium-translocating NADH:quinone oxidoreductase (Na+-NQR) on vibrio cholerae metabolism, motility and osmotic stress resistance.  

PubMed

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

Minato, Yusuke; Fassio, Sara R; Kirkwood, Jay S; Halang, Petra; Quinn, Matthew J; Faulkner, Wyatt J; Aagesen, Alisha M; Steuber, Julia; Stevens, Jan F; Häse, Claudia C

2014-01-01

37

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

PubMed Central

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

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

2014-01-01

38

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

PubMed

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

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

2014-07-01

39

Pressure and temperature dependence of the chlorine NQR in caesium and sodium chlorates.  

PubMed

The (35)Cl nuclear quadrupole resonance (NQR) frequencies (nu(Q)) in caesium and sodium chlorates were measured as a function of temperature, from 77 to 300 K at different pressures up to 5.1 kbar, and the data were analysed to estimate the volume dependence of the electric field gradient (EFG), torsional frequency and also the contributions to the NQR frequency from static and dynamic effects. The variation of spin-lattice relaxation time with pressure at different temperatures was studied in the case of sodium chlorate and at room temperature in case of caesium chlorate. The pressure dependence of the spin-lattice relaxation time (T(1)) suggests that the relaxation is mainly due to the torsional motions. PMID:18324738

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

2008-06-01

40

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

NASA Astrophysics Data System (ADS)

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.

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

2006-06-01

41

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

PubMed

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

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

2011-04-01

42

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

NASA Astrophysics Data System (ADS)

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

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

1983-12-01

43

Two-dimensional NQR using ultra-broadband electronics.  

PubMed

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 (14)N) by using multi-frequency excitation and a single RF coil. Experimental results on pure samples and mixtures are also presented. PMID:24495675

Mandal, S; Song, Y-Q

2014-03-01

44

Structure and phase transition in bis(pyrrolidinium) hexachlorometallates, (C 4H 8NH 2) 2MCl 6 (M=Sn, Te and Pt), studied by X-ray diffraction, 35Cl NQR and DSC  

NASA Astrophysics Data System (ADS)

Single crystal X-ray diffraction, 35Cl nuclear quadrupole resonance (NQR) and differential scanning calorimetry (DSC) measurements were taken for bis(pyrrolidinium) hexachlorometallates, (C 4H 8NH 2) 2MCl 6 (M=Sn, Te and Pt). A solid-solid phase transition was observed at 150(1), 159(1) and 134(1) K for stannate, tellurate and platinate, respectively. 35Cl NQR signals were observed in stannate and platinate, both of which showed a two-line spectrum in the high-temperature phase and a three-line spectrum in the low-temperature phase. The high-temperature phases of the three complexes were found to be isostructural with each other belonging to the space group C2/ m (#12). The C 4H 8NH 2+ and MCl 62- ions are connected by N-H⋯Cl hydrogen bonds forming parallel sheets in the crystals. Disorder of the cation ring appears in these high-temperature phases. Semi-empirical MO calculations were performed to estimate the stable structure of the pyrrolidinium ion.

Ishida, H.; Furukawa, Y.; Sato, S.; Kashino, S.

2000-06-01

45

NQR spin-echo methods at very low temperatures  

Microsoft Academic Search

Pulsed methods may be successfully used in very low temperature NMR or NQR experiments provided good thermal anchoring of the sample is achieved. In order to reduce heating effects, it is advantageous to use rf pulses that are shorter than the standard magnetization tipping pulses used at higher temperatures. The present work describes the use of short nonstandard rf pulses

I. P. Goudemond; J. M. Keartland; M. J. R. Hoch

1991-01-01

46

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

PubMed

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

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

2012-10-01

47

Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms  

NASA Astrophysics Data System (ADS)

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.

Malone, Michael W.

48

Stark effect of 14N NQR in single crystals of ferroelectric NaNO2  

Microsoft Academic Search

The effects of the external electric field on 14N nuclear quadrupole resonance (NQR) have been investigated in the ferroelectric phase of sodium nitrite (NaNO2) single crystals with either the single domain or the multidomain structure. NQR measurements of two resonance lines of n and n were made at 77 K under the external electric field up to 25 kV\\/cm. The

S. H. Choh; Y. J. Park; H. K. Kim; Y. M. Chang

1989-01-01

49

Possible stripe fluctuations in La2 - x - yNdySrxCuO4 at room temperature observed by 63Cu NQR spectroscopy  

NASA Astrophysics Data System (ADS)

63Cu nuclear quadrupole resonance (NQR) studies at room temperature were reported on six Nd-doped La2 - xSrxCuO4 samples. The NQR spectrum for La1.48Nd0.4Sr0.12CuO4 has a different line shape compared with those from the other samples, which is similar to the case of the insulating La2CuO4. This may suggest that the stripe fluctuations at such a special Nd and Sr doping fall into the frequency window of 63Cu NQR. The spectra of the other five samples were analysed by pairs of 63Cu and 65Cu Gaussians at A and B sites. The full width of half-maxim (FWHM) for 63Cu at B sites is anomalously large for La1.45Nd0.4Sr0.15CuO4, which was considered to be related to the stripe fluctuations.

Zhang, Q.-M.; Ying, X. N.; Gu, M.; Wang, Y. N.

2005-04-01

50

A general numerical analysis of time-domain NQR experiments.  

PubMed

We introduce a general numerical approach for solving the Liouville equation of an isolated quadrupolar nuclide that can be used to analyze the unitary dynamics of time-domain NQR experiments. A numerical treatment is necessitated by the dimensionality of the Liouville space, which precludes analytical, closed form solutions for I > 3/2. Accurate simulations of experimental nutation curves, forbidden transition intensities, powder and single crystal spectra, and off-resonance irradiation dynamics can be computed with this method. We also examine the validity of perturbative approximations where the signal intensity of a transition is proportional to the transition moment between the eigenstates of the system, thus providing a simple basis for determining selection rules. Our method allows us to calculate spectra for all values of the asymmetry parameter, eta, and sample orientations relative to the coil axis. We conclude by demonstrating the methodology for calculating the response of the quadrupole system to amplitude- and frequency-modulated pulses. PMID:16996760

Harel, Elad; Cho, Herman

2006-12-01

51

^63Cu NQR relaxation in the p-type transparent conductor CuScO_2:Mg  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides with p-type conductivity are of interest as electronic complements to the more familiar n-type transparent conductors. This paper reports the first results of a study of carrier spin dynamics in p-type CuScO_2:Mg using ^63Cu nuclear spin-lattice relaxation measurements. Relaxation rates 1/T1 have been measured by nuclear quadrupole resonance (NQR) over the range 280 K to 400 K. The ^63Cu NQR frequency is found to be 28,135 ± 5 kHz at 300 K and to decrease linearly with temperature over the experimental range. The value of 1/T1 at 300 K is 130 ± 10 s-1. The rate is weakly dependent on temperature and increases by only about 15 % up to 400 K. This behavior contrasts sharply with results obtained previously(1. A. Rajabzadeh, J. Tate and W. Warren, Bull. Am. Phys. Soc. 48, 1009 (2003).) for the related material CuYO_2:Ca. In that material, relaxation rates for ^63Cu and ^65Cu were strongly temperature dependent, being approximately thermally-activated with activation energy 152 ± 10 meV. The nuclear relaxation properties of CuScO_2:Mg are suggestive of more conventional metallic transport in CuScO_2:Mg compared with CuYO_2:Ca.

Rossi, Vincent; Tate, Janet; Warren, William; Li, Jun; Sleight, Arthur

2003-05-01

52

NQR1 controls lifespan by regulating the promotion of respiratory metabolism in yeast  

PubMed Central

Summary The activity and expression of plasma membrane NADH coenzyme Q reductase is increased by calorie restriction (CR) in rodents. Although this effect is well established and is necessary for CR's ability to delay aging, the mechanism is unknown. Here we show that the Saccharomyces cerevisiae homolog, NQR1, resides at the plasma membrane and when overexpressed extends both replicative and chronological lifespan. We show that NQR1 extends replicative lifespan in a SIR2-dependent manner by shifting cells towards respiratory metabolism. Chronological lifespan extension, in contrast, occurs via a SIR2-independent decrease in ethanol production. We conclude that NQR1 is a key mediator of lifespan extension by CR through its effects on yeast metabolism and discuss how these findings could suggest a function for this protein in lifespan extension in mammals.

Jimenez-Hidalgo, Maria; Santos-Ocana, Carlos; Padilla, Sergio; Villalba, Jose M.; Lopez-Lluch, Guillermo; Martin-Montalvo, Alejandro; Minor, Robin K.; Sinclair, David A.; de Cabo, Rafael; Navas, Placido

2009-01-01

53

Cu-NQR of CeCu2Si2 under high pressure  

NASA Astrophysics Data System (ADS)

We have measured 63Cu-NQR spectral lines and nuclear spin-lattice relaxation time T1 under pressure up to 5.4 GPa. Daphne oil 7474 is used as the pressure-transmitting medium to obtain good hydrostaticity. NQR frequency 63?q above 4 GPa suddenly decreases from the linear pressure dependence in the low pressure range (P <= 3.5 GPa). The observed sudden downward deviation of 63?q is associated with an increase of Ce valence. Above 4.5 GPa, the linear pressure dependence of 63?q is observed again, most likely related to the sharp crossover to the high valence state.

Fujiwara, K.; Iwata, M.; Okazaki, Y.; Ikeda, Y.; Araki, S.; Kobayashi, T. C.; Murata, K.; Geibel, C.; Steglich, F.

2012-12-01

54

Optimised NQR pulse technique for the effective detection of Heroin Base.  

PubMed

The nuclear quadrupole resonance (NQR) method has been applied to Heroin Base (HB) to find an optimised multi-pulse technique for effective detection of HB. Experimental results of applying the proposed spin-locking multi-pulse (SLMP) technique to nitrogen-14 NQR in this sample are presented and convincingly demonstrate as a path towards efficient detection. A detection using a sequence of this character could be achieved over real-world scan volumes for screening of goods. All experiments were carried out at room temperature. PMID:18342493

Rudakov, T N; Hayes, P A; Flexman, J H

2008-03-01

55

Measurement of the spin-lattice relaxation time in the NQR of light nuclei  

SciTech Connect

This work proposed a method for increasing the signal/noise ratio in NQR by preliminary magnetization of the sample in a constant magnetic field B/sub 0/ and it subsequent adiabatic demagnetization. The proposed method for the measurement of spin-lattice relaxation times is verified experimentally with a number of compounds. The results agree well with published data.

Anferov, V.P.; Anferova, S.V.; Grechishkin, V.S.; Sinyavskii, N.Ya.

1988-01-01

56

Nuclear quadrupole resonance study of hydrogen bonded solid materials.  

PubMed

Nuclear quadrupole resonance is presented as a method for the study of solid hydrogen bonded materials. NQR study of hydrogen bonds in ferroelectric and paraelectric KH2PO4, antiferroelectric and paraelectric squaric acid, ferroelectric croconic acid and antiferroelectric and paraelectric cocrystal 5'-dimethyl-2, 2'-bipyridine - chloranilic acid (1:1) are discussed in more details. A 14N NQR study of the strong short O-HKN hydrogen bond in two polymorphic forms of cocrystal isonicotinamide-oxalic acid (2:1) is presented as well. Various correlations between the NQR parameters and between the NQR and structural parameters have been observed. These correlations may be used to determine the proton position in a hydrogen bond and some other structural parameters from the NQR data. PMID:24062106

Seliger, Janez

2011-09-01

57

Neutral-Ionic Phase Transition in DMTTF-QCl4 Investigated by 35Cl NQR  

NASA Astrophysics Data System (ADS)

We report a 35Cl NQR investigation into the neutral-ionic (NI) phase transition in DMTTF-QCl4 (4,4'-dimethyltetrathiafulvalene- p-chloranil), the end material of the family containing an NI quantum transition system. Four distinct lines with comparable intensities were observed well below Tc=65 K; this observation is consistent with the antiferroelectric nature of the ionic phase. The temperature dependences of the spectral shift and splitting below Tc are moderate in contrast with the case of TTF-QCl4. Low-energy charge-lattice fluctuations are observed around Tc as a drastic increase of 1/T1, allowing the observation of the quantum fluctuations in a chemically substituted complex. An analysis of the NQR spectra yields detailed temperature variations in the charge transfer and the concomitant lattice distortion around the NI transition.

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

2007-07-01

58

Ru NQR Probe of Superconducting Property in Impurity-Doped CeRu 2  

Microsoft Academic Search

Superconducting characteristics of CeRu2 have been investigated by systematic measurements of the nuclear-spin lattice relaxation rate, 1\\/T1 of 101Ru on pure and impurity-substituted CeRu2, employing an NQR technique in zero magnetic field. (1\\/T1) for CeRu2 shows a broad coherence plateau just below T c followed by an exponential decrease well below T c. By contrast, a distinct coherence peak of

Hidekazu Mukuda; Kenji Ishida; Yoshio Kitaoka; Kunisuke Asayama

1998-01-01

59

Addition compounds of antimony trichloride and tribromide. Crystal structure and charge transfer from NQR data  

NASA Astrophysics Data System (ADS)

The correlation analysis of the quadrupcle coupling constants(QCC) for the antimony nuclei in the intermolecular compounds of SbCl 3 and SbBr 3 with aromatic hydrocarbons is carried out. The results confirm a supposition about the general similarity of the crystal structures of these complexes. The correlative dependence between the antimony QCC values and also the results of the chlorine and bromine NQR spectra Investigation permit the evaluation of the relative acceptor strength of the antimony trihalide molecules.

Kjuntsel, I. A.; Gordeev, A. D.

60

NQR Line Broadening Due to Crystal Lattice Imperfections and Its Relationship to Shock Sensitivity  

NASA Astrophysics Data System (ADS)

The hydrodynamic hot spot model is used to explain the difference between shock sensitive and shock insensitive explosives. Among the major factors that influence the shock sensitivity of energetic compounds are the quality and particle size of the energetic crystals used to formulate the cast plastic bonded explosive. As do all energetic compounds, RDX and HMX exhibit internal crystal defects the magnitude and type of which depend on the manufacturing process used to synthesize and re-crystallize the energetic compound. Nuclear Quadrupole Resonance (NQR) spectroscopy was used to determine the crystal quality of RDX, HMX and CL-20 obtained from various manufacturers. The NQR experimental results are discussed. Cast plastic bonded explosives were made using the RDX and HMX obtained from the various manufacturers and subsequently subjected to the NOL large-scale gap test (LSGT). The results of the LSGT are discussed and correlated with the NQR results. A relationship between the crystal defect density and shock initiation pressure of the plastic bonded explosive is developed and discussed.

Caulder, S. M.; Buess, M. L.; Garroway, A. N.; Miller, P. J.

2004-07-01

61

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

NASA Technical Reports Server (NTRS)

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.

Brinkmann, D.

1995-01-01

62

63Cu-NMR/NQR studies on apical-F bi-layered cuprates Ba2CaCu2O4F2 and Ba2CaCu2O4(F1.6O0.4)  

NASA Astrophysics Data System (ADS)

We report 63Cu-NMR/NQR on the bi-layered high- Tc copper oxide Ba2CaCu2O4F2, which is expected to be a Mott insulator in an ideal case of a nominal content of fluorine, and less fluorinated Ba2CaCu2O4(F1.6O0.4) to clear the doping mechanism in apical-fluorine multilayered system Ba2CaCunO2nF2, where n is the number of the layers in a unit cell. In the case of n=3 and, especially, n=4, the origin of carrier doping has been attributed to a self-doping mechanism based on the nominal stoichiometry; electrons are transferred between the inner CuO2 plane (IP) and the outer one (OP), keeping Cu+2 on average. It is revealed that Ba2CaCu2O4F2 is an underdoped superconductor with hole carriers, doped by an inevitable deviation from the nominal content of apical fluorines. This result suggests that hole carriers are doped in the same manner for the case of n=3 and 4, and that we should reconsider the self-doping mechanism as the carrier source in the apical-fluorine system.

Shimizu, S.; Sakaguchi, T.; Mukuda, H.; Kitaoka, Y.; Iyo, A.; Shirage, P. M.; Kito, H.; Kodama, Y.

2009-10-01

63

Multiple-pulse NQR dynamics of spin systems with strong heteronuclear coupling  

NASA Astrophysics Data System (ADS)

The results are presented of a theoretical consideration of the nuclear quadrupole resonance (NQR) and spin—spin relaxation for a paramagnetic body containing nuclei of two different sorts coupled by the strong homonuclear and heteronuclear dipole—dipole interactions and influenced by an external multiple-pulse radiofrequency magnetic field acting only on nuclei of one sort. Kinetic equations were obtained giving the possibility of finding the time dependence of the magnetization of the body and the kinetic coefficients calculated as a function of the multiple-pulse field parameters. The possibilities of using the results in question for molecular structure and molecular dynamics investigations are briefly surveyed.

Furman, G. B.; Shaposhnikov, I. G.

1994-05-01

64

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)

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.

Asaji, Tetsuo

2013-05-01

65

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

SciTech Connect

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.

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

1980-12-01

66

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

NASA Astrophysics Data System (ADS)

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

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

2007-06-01

67

Relaxation Anomalies of 69/71Ga NQR in the Paramagnetic State of the Itinerant Antiferromagnet UGa3: Possible Evidence for a Crossover to Localized Spin Fluctuations and Development of Orbital Fluctuations of 5f-electrons at High Temperatures  

NASA Astrophysics Data System (ADS)

The microscopic magnetic properties of the itinerant 5f-electron antiferromagnet UGa3 (TN=67 K) have been investigated in the paramagnetic state by means of Ga NQR studies of the two naturally abundant isotopes 69Ga and 71Ga. A striking and unusual increase of the nuclear longitudinal relaxation rate 1/T1 has been observed above 230 K, which includes a strong component of nuclear quadrupolar relaxation. Both the magnetic and quadrupolar relaxation rates have been found to increase simultaneously above 230 K. Correspondingly, the NQR frequencies also show a clear deviation from lower-T T3/2-dependence above 230 K. These results are discussed in terms of a crossover from lower-T itinerant to higher-T more localized spin fluctuations and associated orbital fluctuations on the part of the U 5f electrons. A mechanism of transferred quadrupole interaction is presented, through which the fluctuations among the U 5f orbitals involve those among the counter-anion Ga 4p orbitals and thereby cause quadrupolar relaxation of the Ga nuclear spins.

Takagi, Shigeru; Muraoka, Hideaki; Matsuda, Tatsuma D.; Haga, Yoshinori; Kambe, Shinsaku; Walstedt, Russell E.; Yamamoto, Etsuji; ?nuki, Yoshichika

2004-02-01

68

NMR and NQR fluctuation effects in layered superconductors  

Microsoft Academic Search

We study the effect of thermal fluctuations of the s-wave order parameter of a quasi-two-dimensional superconductor on the nuclear spin relaxation rate near the transition temperature TC. We consider both the effects of the amplitude fluctuations and the Berezinskii-Kosterlitz-Thouless (BKT) phase fluctuations in weakly coupled layered superconductors. In the treatment of the amplitude fluctuations we employ the Gaussian approximation and

D. Fay; J. Appel; C. Timm; A. Zabel

2001-01-01

69

Application of the spherical tensor method for Two-Frequency pure NQR of spin I =1 nuclei  

Microsoft Academic Search

The results of a theoretical investigation of two-frequency excitation in pure nuclear quadrupole resonance (NQR) for a spinI=1 nucleus with a nonaxial elecric field gradient are presented. The multipole tensor operator technique is used for the treatment\\u000a of the one- and two-frequency pulse excitations. The results are applied to the characterization of the two-frequency signal\\u000a of nitrogen14N nuclei. The experiments

G. V. Mozjoukhine

2002-01-01

70

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

SciTech Connect

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.

Yesinowski, J.P.; Buess, M.L.; Garroway, A.N. [Naval Research Lab., Washington, DC (United States); Ziegeweid, M.; Pines, A. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

1995-07-01

71

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

SciTech Connect

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.

Ziegeweid, M.A.

1995-11-29

72

N.Q.R measurements of low energy Chiral structures in powdered glassy As2Se3  

NASA Astrophysics Data System (ADS)

Experimental and theoretical work on the As-chalcogen glasses have shown that in the glassy state the local cylindrical symmetry associated with the elemental pyramidal unit is preserved. Here we introduce a local paracrystalline model of glassy As2Se3. This model is based on a tight binding calculation of the electric field gradient (EFG) at the core of an As atom located at the apex of the pyramidal structure. This EFG is shown to be hyper sensitive to the bond angles and bond lengths the As atom forms with the chalcogen nearest neighbors, as well as the hybrid angle formed with second neighbor As atoms. A continuous variation of the bonding parameters produces a unique set of these pyramidal units which are shown to fit the NQR data for powdered glassy samples. The best fit to the NQR data indicates that the pyramidal units organize themselves into Chiral structures in the glass. A plot of the electronic energy per molecular site shows that the chiral structures have on average a lower electronic energy than a random configuration.

Nelson, Chris

2012-02-01

73

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

NASA Technical Reports Server (NTRS)

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.

Borsa, F.; Rigamonti, A.

1991-01-01

74

INDO Investigation of the halogen N.Q.R. frequencies and 14 N nuclear quadrupole coupling constants of halothiophenes and halopyridines  

Microsoft Academic Search

The 35Cl, 79Br, and 127I N.Q.R. frequencies of a number of halothiophenes and halopyridines and the 14N nuclear quadrupole coupling constants of halopyridines have been determined in terms of the Kaplansky-Whitehead theory with the INDO MO approximations using a consistent set of atomic parameters derived from SCF Hartree-Fock calculations. The theoretical spectral properties are in satisfactory overall agreement with experiment.

V. Galasso

1974-01-01

75

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

NASA Astrophysics Data System (ADS)

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.

Pramanik, Sanhita

76

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

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

77

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

NASA Astrophysics Data System (ADS)

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.

Borsa, F.; Rigamonti, A.

1990-04-01

78

Structural study of selected polyhalogenated benzimidazoles (protein kinase CK2 inhibitors) by nuclear quadrupole double resonance, X-ray, and density functional theory.  

PubMed

Protein kinase CK2 inhibitors, polyhalogenated benzimidazoles, have been studied experimentally in solid state by NMR-NQR double resonance and X-ray and theoretically by the density functional theory (DFT). Six resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in each polyhalogenated benzimidazole molecule. The effects of prototropic annular tautomerism and polymorphism related to stable cluster formation due to intermolecular hydrogen bonding interactions on the (14)N NQR parameters have been analyzed within the DFT and AIM (atoms in molecules) formalism. The studies suggest that all polyhalogenobenzimidazoles are isostructural and can exhibit polymorphism and that (14)N NQR is very sensitive to hydrogen bondings but less sensitive to the specific arrangement of the hydrogen bonded molecules. NQDR and DFT results suggest the presence of the prototropic annular tautomerism 50:50, which is in a good agreement with the X-ray and (1)H NMR data. PMID:20055520

Latosi?ska, J N; Latosi?ska, M; Seliger, J; Zagar, V; Maurin, J K; Orzeszko, A; Kazimierczuk, Z

2010-01-14

79

Novel Phase Transition in CeRu2Al10 Probed by 27Al-NQR/NMR —No Evidence of Magnetic Ordering—  

NASA Astrophysics Data System (ADS)

The 27Al-NQR/NMR measurements of CeRu2Al10 were carried out to clarify the unusual phase transition at T0=27 K. Distinct NQR peaks associated with five nonequivalent Al sites have been observed at T > T0, and each peak is successfully assigned to their respective Al sites. Below the transition temperature T < T0, each peak simply splits into two peaks except for one site. This indicates that the phase transition is not accompanied by magnetic order, but is presumably associated with the onset of structural transition with lowering symmetry. The nuclear spin-lattice relaxation rate 1/T1 suggests a local moment picture above T*˜ 60 K, and the development of Kondo coherence toward T0. Below T0, 1/T1 shows a gaplike decrease with a gap magnitude of 106 K, being consistent with the macroscopic measurements. The Korringa term below 10 K after the gaplike decrease suggests a gap opening over a portion of the Fermi surface.

Matsumura, Masahiro; Kawamura, Yukihiro; Edamoto, Shingo; Takesaka, Tomoaki; Kato, Harukazu; Nishioka, Takashi; Tokunaga, Yo; Kambe, Shinsaku; Yasuoka, Hiroshi

2009-12-01

80

NQR investigation of pressure-induced charge transfer in oxygen-deficient YBa sub 2 Cu sub 3 O sub 7-. delta. (. delta. = 0. 38)  

SciTech Connect

Measurements of the pressure dependence of {sup 63}Cu nuclear quadrupole frequency in YBa{sub 2}Cu{sub 3}O{sub 6.62} from ambient pressure up to 1.5 GPa at 4k have been performed. {Tc} was found to increase with pressure: d{Tc}/dp {approximately} 5 K/GPa. All observed NQR lines are linear in pressure: dln{nu}{sub Q}/dp=z. We found positive z for the empty chain sites, consistent with ionic (Cu{sup 1+}) configuration in which the atom simply feels a squeezing lattice. Planar coppers close to the empty chains have positive z, while those that are close to full chains have z {approximately} 0. We present an analysis of the NQR result on the basis of the charge transfer model in which the mobile charges migrate from the chain to the plane sites. We deduced that a transfer of 0.021 holes to the O(2,3) sites would explain the result in YBa{sub 2}Cu{sub 3}O{sub 6.62}, whereas only 0.007 holes transfer in fully oxygenated YBa{sub 2}Cu{sub 3}O{sub 7}.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H. (Los Alamos National Lab., NM (United States)); Takigawa, M. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center)

1992-01-01

81

Density functional calculations of 14N and 11B NQR parameters in the H-capped (6,0) and (4,4) single-walled BN nanotubes  

NASA Astrophysics Data System (ADS)

Density functional theory (DFT) calculations were performed to calculate nitrogen-14 and boron-11 nuclear quadrupole resonance (NQR) spectroscopy parameters in the representative considered models of zigzag and armchair boron nitride nanotubes (BNNTs) for the first time. The considered models consisting of 1 nm length of H-capped (6,0) and (4,4) single-walled BNNT were first allowed to fully relax and then the NQR calculations were performed on the geometrically optimized models. The evaluated nuclear quadrupole coupling constants and asymmetry parameters for the mentioned nuclei reveal that the considered models can be divided into four layers of nuclei with an equivalent electrostatic environment where those nuclei at the ends of tubes have a very strong electrostatic environment compared to the other nuclei along the length of tubes. Those nuclei at the center of the tube length also have an equivalent electrostatic environment. The calculations were performed based on the B3LYP DFT method and 6-311G** and 6-311++G** standard basis sets using the Gaussian 98 package of program.

Mirzaei, Mahmoud; Hadipour, Nasser L.

2008-02-01

82

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

NASA Astrophysics Data System (ADS)

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.

Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

2013-07-01

83

NQR investigation of pressure-induced charge transfer in oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} ({delta} = 0.38)  

SciTech Connect

Measurements of the pressure dependence of {sup 63}Cu nuclear quadrupole frequency in YBa{sub 2}Cu{sub 3}O{sub 6.62} from ambient pressure up to 1.5 GPa at 4k have been performed. {Tc} was found to increase with pressure: d{Tc}/dp {approximately} 5 K/GPa. All observed NQR lines are linear in pressure: dln{nu}{sub Q}/dp=z. We found positive z for the empty chain sites, consistent with ionic (Cu{sup 1+}) configuration in which the atom simply feels a squeezing lattice. Planar coppers close to the empty chains have positive z, while those that are close to full chains have z {approximately} 0. We present an analysis of the NQR result on the basis of the charge transfer model in which the mobile charges migrate from the chain to the plane sites. We deduced that a transfer of 0.021 holes to the O(2,3) sites would explain the result in YBa{sub 2}Cu{sub 3}O{sub 6.62}, whereas only 0.007 holes transfer in fully oxygenated YBa{sub 2}Cu{sub 3}O{sub 7}.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H. [Los Alamos National Lab., NM (United States); Takigawa, M. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center

1992-03-01

84

Evolution of an Unconventional Superconducting State inside the Antiferromagnetic Phase of CeNiGe3 under Pressure: A 73Ge-Nuclear-Quadrupole-Resonance Study  

NASA Astrophysics Data System (ADS)

We report a 73Ge nuclear-quadrupole-resonance (NQR) study on novel evolution of unconventional superconductivity in antiferromagnetic (AFM) CeNiGe3. The measurements of the 73Ge-NQR spectrum and the nuclear spin-lattice relaxation rate (1/T1) have revealed that the unconventional superconductivity evolves inside a commensurate AFM phase around the pressure (P) where Néel temperature TN exhibits its maximum at 8.5 K. The superconducting transition temperature TSC has been found to be enhanced with increasing TN, before reaching the quantum critical point at which the AFM order collapses. Above TSC, the AFM structure transits from an incommensurate spin-density-wave order to a commensurate AFM order at T˜ 2 K, accompanied by a longitudinal spin-density fluctuation. With regard to heavy-fermion compounds, these novel phenomena have hitherto never been reported in the P-T phase diagram.

Harada, Atsushi; Mukuda, Hidekazu; Kitaoka, Yoshio; Thamizhavel, Arumugam; Okuda, Yusuke; Settai, Rikio; ?nuki, Yoshichika; Itoh, Kouhei M.; Haller, Eugene E.; Harima, Hisatomo

2008-10-01

85

Electron configuration and hydrogen-bonding pattern in several thymine and uracil analogues studied by 1H-14N NQDR and DFT/QTAIM.  

PubMed

Some thio- and aza-derivatives of natural nucleobases uracil and thymine: 2-thiouracil, 4-thiouracil, 6-methyl-2-thiouracil, 6-azauracil, and 6-aza-2-thiothymine have been studied experimentally in solid state by (1)H-(14)N NMR-NQR double resonance (NQDR) and theoretically by the Density Functional Theory (DFT)/Quantum Theory of Atoms in Molecules (QTAIM). The (14)N resonance frequencies have been measured at 173 and 295 K and assigned to particular nitrogen sites (-N? and -NH-). The temperature factor has been found negligible. The changes in the molecular skeletons, electric charge distribution, intermolecular interactions pattern, and molecular aggregations caused by oxygen replacement with sulfur and carbon replacement with nitrogen are discussed in detail. Correlations between all the principal components of the (14)N quadrupole coupling tensor have been found helpful in the search for the experimental (14)N NQR frequencies, their assignment to a particular nitrogen positions and estimation of the strength of the inter- and intramolecular interactions. The variation in the NQR parameters have been mainly related to the variation in the population of ?-electron orbital. For thiouracil derivatives a general trend is that the stronger the hydrogen bond is, the lower is the asymmetry parameter, while for thymine and 6-aza-2-thiotymine, the opposite relation holds. Differences in correlations of the principal components of the (14)N quadrupole coupling tensor at the amino and iminonitrogen positions in heterocyclic rings are discussed. The effect of C?H and C?N substitution at the amino nitrogen position and C?N substitution at the iminonitrogen position on the quadrupole coupling tensor is analyzed. This study also demonstrates the advantages of combining NQR and DFT/QTAIM to predict an unsolved crystalline structure of 4-thiouracil. PMID:22747063

Seliger, Janez; Žagar, Veselko; Latosi?ska, Magdalena; Latosi?ska, Jolanta Natalia

2012-08-01

86

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

SciTech Connect

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.

Jayakody, J.R.P.

1993-12-31

87

Reconstructive Phase Transformation and Kinetics of Cs 3Sb 2I 9by Means of Rietveld Analysis of X-Ray Diffraction and 127I NQR  

NASA Astrophysics Data System (ADS)

The reconstructive phase transformation between two polymorphs of Cs 3Sb 2I 9has been studied kinetically by means of powder X-ray diffraction and 127INQR spectroscopy. The low-temperature form of Cs 3Sb 2I 9contains isolated dimer anions, whereas the high-temperature form consists of polyanions in which distorted SbI 6octahedra form infinite layers viaiodine bridges. The activation energy required for the reconstructive phase transition was determined to be 189±5 kJ/mol, which corresponds to the energy required to break two Sb-I(bridge) bonds of the dimer anion. The mechanism of this reconstructive phase transition was discussed on the basis of their structures and kinetic parameters.

Yamada, Koji; Sera, Hiroshi; Sawada, Shigeko; Tada, Hironobu; Okuda, Tsutomu; Tanaka, Haruhiko

1997-12-01

88

Correlation of far-infrared and nuclear quadrupole resonance studies in 1,3,5-tribromobenzene  

NASA Astrophysics Data System (ADS)

The torsional modes that contribute to the change in nuclear quadrupole resonance (NQR) frequencies with temperatures in 1,3,5-tribromobenzene are indentified by correlating the observed variation of 79Br NQR frequencies with temperature with the theoretical expectations using the low frequency vibrational modes obtained from the far-infrared (FIR) spectrum.

Venkatacharyulu, P.; Krishnamurthy, V.

1991-02-01

89

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

SciTech Connect

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.

Bota, K.B.

1991-01-01

90

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

SciTech Connect

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.

Bota, K.B.

1991-12-31

91

13C CP MAS NMR and DFT study of vascular-selective drugs felodipine and amlodipine  

NASA Astrophysics Data System (ADS)

Amlodipine besylate (AM) and felodipine (FL) have been studied in solid by 13C CP MAS NMR and DFT. The spectra have been successfully reproduced from the theoretical calculations of the nuclear magnetic shielding tensors, using the GIAO method, after the SCF partial geometry optimisation. A very good correlation between the 13C chemical shifts and quadrupole coupling constants for chlorobenzene, AM and FL was obtained. 13C NMR as well as 35Cl NQR do not differentiate between S and R enantiomers of AM and FL due to the symmetry of the 4-aryl ring comprising one (AM) or two (FL) chlorine atoms oriented in a perpendicular fashion over the 1,4-DHP ring.

Latosi?ska, J. N.

2008-09-01

92

Sequencing and preliminary characterization of the Na+-translocating NADH:ubiquinone oxidoreductase from Vibrio harveyi.  

PubMed

The Na(+)-translocating NADH: ubiquinone oxidoreductase (Na(+)-NQR) generates an electrochemical Na(+) potential driven by aerobic respiration. Previous studies on the enzyme from Vibrio alginolyticus have shown that the Na(+)-NQR has six subunits, and it is known to contain FAD and an FeS center as redox cofactors. In the current work, the enzyme from the marine bacterium Vibrio harveyi has been purified and characterized. In addition to FAD, a second flavin, tentatively identified as FMN, was discovered to be covalently attached to the NqrC subunit. The purified V. harveyi Na(+)-NQR was reconstituted into proteoliposomes. The generation of a transmembrane electric potential by the enzyme upon NADH:Q(1) oxidoreduction was strictly dependent on Na(+), resistant to the protonophore CCCP, and sensitive to the sodium ionophore ETH-157, showing that the enzyme operates as a primary electrogenic sodium pump. Interior alkalinization of the inside-out proteoliposomes due to the operation of the Na(+)-NQR was accelerated by CCCP, inhibited by valinomycin, and completely arrested by ETH-157. Hence, the protons required for ubiquinol formation must be taken up from the outside of the liposomes, which corresponds to the bacterial cytoplasm. The Na(+)-NQR operon from this bacterium was sequenced, and the sequence shows strong homology to the previously reported Na(+)-NQR operons from V. alginolyticus and Haemophilus influenzae. Homology studies show that a number of other bacteria, including a number of pathogenic species, also have an Na(+)-NQR operon. PMID:10587447

Zhou, W; Bertsova, Y V; Feng, B; Tsatsos, P; Verkhovskaya, M L; Gennis, R B; Bogachev, A V; Barquera, B

1999-12-01

93

B 24 N 24 nanocages: a GIAO density functional theory study of 14 N and 11 B nuclear magnetic shielding and electric field gradient tensors  

Microsoft Academic Search

\\u000a Abstract  Density functional theory (DFT) calculations were performed to determine boron-11 and nitrogen-14 nuclear magnetic resonance\\u000a (NMR) and nuclear quadrupole resonance (NQR) spectroscopy parameters in the three most stable B24N24 fullerenes for the first time. The considered samples were first allowed to relax entirely, and then the NMR and NQR calculations\\u000a were performed on the geometrically optimized models. The calculations of

Goudarz Mohseni Rouzbehani; Asadollah Boshra; Ahmad Seif

2009-01-01

94

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

PubMed

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

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

2014-01-01

95

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

PubMed Central

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

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

2014-01-01

96

Multi-Frequency Resonances in Pure Multiple-Pulse NQR  

NASA Astrophysics Data System (ADS)

We have observed multi-frequency resonances in a system with a spin 3/2 irradiated simultaneously by a multiple-pulse radiofrequency sequence and a low frequency field swept in the range 0 ÷ 80 kHz. The theoretical description of the effect is presented using both the rotating frame approximation and the Floquet theory. Both approaches give indentical results at the calculation of the resonance frequencies, transition probabilities and shifts of resonance frequency. The calculated magnetization vs. the frequency of the low-frequency field agrees with the obtained experimental data.

Furman, G. B.; Kibrik, G. E.; Polyakov, A. Yu.

2004-12-01

97

Optimal filtering in multipulse sequences for nuclear quadrupole resonance detection  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

98

Muon-Spin-Rotation study of PrxY1-xBa2Cu3O7: Pr at Ba sites, and other anomalies.*  

NASA Astrophysics Data System (ADS)

Muon-spin-rotation data of (PrxY1-x)BCO recorded at room temperature (RT) have been analyzed by the Maximum-Entropy Burg technique. For different Pr doping, the obtained magnetic field distributions show distinct differences. Apparently, not all Pr ions are at the rare-earth sites. NQR has suggested evidence of some Pr at the Ba sites. [1] This Pr occupation requires an extra O(2-) at an oxygen-vacancy site. Thus, the muon-probe environment will change. [2] The field distributions have been fitted using two Lorentzians, affirming trends seen for the (x < 0.5) superconductors. These trends correlate with Tc(x), and indicate Pr presence in BaO layers. Further, we are studying the effect of Pr doping on the vortex field distributions in (PrxY1-x)BCO. For vortex states (x = 0.2 and 0.4) below 30 K, we have found similar anomalies in the magnetic field distributions, as seen for RBCO. [3] [1] Reyes, Abdelrazek et al, M2S-HTSC-VI Conf Proc, Physica C341-348 (2000) 2129. [2] Dawson et al, Hyperfine Interactions 63 (1990) 219. [3] Boekema et al, Physica C282-287 (1997) 2069, and Phys Rev B63 in print.

Aslanian, Helen; Tun, Magnolia; Boekema, Carel

2001-03-01

99

Low-temperature nuclear quadrupole resonance studies of antimony and application to thermometry  

NASA Astrophysics Data System (ADS)

The spin-lattice retaxation time, Tsb1, of finely divided powdered metallic antinomy immersed in liquid sp3He was measured using pulsed Nuclear Quadrupole Resonance (NQR) techniques. In this technique, the nuclear quadrupole resonant antinomy nuclei were saturated using an RF pulse. The recovery back to equilibrium was monitored using short inspection pulses and the magnetization recovery follows a recovery curve characterized by the relaxation time Tsb1. Tsb1 measurements were performed at temperatures ranging from 150 mK to 1.25 mK. Temperatures down to 11 mK were achieved by using a dilution refrigerator. Lower temperatures were achieved using adiabatic nuclear demagnetization of a copper bundle starting at 8.5 Tesla (7.5 Tesla average field over the copper bundle). The sample was cooled by immersion in liquid sp3He which is in thermal contact with silver sinter packed in the bottom of a silver cell. This cell was bolted onto a cold plate attached to the copper bundle. It was found that a low temperatures starting near 75 mK, the measured total relaxation was significantly enhanced with respect to the Korringa relaxation, the dominant relaxation mechanism expected for a metal at these temperatures. This enhancement is attributed to a surface relaxation mechanism mediated by the surface sp3He atoms. In systems immersed in liquid sp3He, a surface relaxation mechanism is present due to a modulation of the interaction between the solid-like sp3He atoms on the surface and the surface spins. This modulation is due to the quantum zero-point motion of the sp3He atoms on the surface. This phenomenon has been well studied in insulating systems using Nuclear Magnetic Resonance. The measurements undertaken in this study demonstrate that this phenomenon is present in a metallic and quadrupolar system. This surface relaxation mechanism becomes the dominant relaxation mechanism at low temperatures. Considering the surface and bulk spins as belonging to different phases, a two phase relaxation analysis was used to extract the surface relaxation parameters. This work helps explain previous relaxation measurements by other groups, on powdered metals (with spin I? 0) immersed in liquid sp3He. In these studies, anomalies were reported whose features are consisted with the surface relaxation mechanism discussed in this work. Using magnetic field perturbed NQR, the intensity ratio of two transitions was studied from 1.4 mK to 0.25 mK. The intensity ratio was observed to change as a function of temperature. A comparison is made with the expected Boltzmann distribution. This intensity ratio can be used as a self-calibrating, absolute thermometer for the ultra-low temperature region.

Genio, Edgar Baylon

1997-11-01

100

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

101

Magnetic resonance study of arsenic bonding sites in ternary chalcogenide glasses  

NASA Astrophysics Data System (ADS)

75As NQR and high-field NMR experiments have been performed on Ge xAs ySe 1- x- y glasses. Evolution of As bonding structure from arsenic sites with axially symmetric distribution of the electric field gradient (EFG) to highly asymmetric As surroundings has been revealed. Arsenic atoms form pyramidal structural units in Ge 2As 2Se 7 with no evidence of significant concentration of homopolar bonds. In Ge 2As 2Se 5 most of arsenic atoms form structural units with two As-As bonds per atom and asymmetric EFG distribution. Arsenic bondings become more complicated in Ge 0.33As 0.12Se 0.55 where all arsenic sites are highly distorted. The combination of NQR and NMR data provide valuable information on arsenic bonding dynamics in these glasses.

Mammadov, E.; Bobela, D.; Reyes, A.; Mehdiyeva, S.; Taylor, P. C.

2011-10-01

102

Low-temperature nuclear quadrupole resonance studies of antimony and application to thermometry  

Microsoft Academic Search

The spin-lattice retaxation time, Tsb1, of finely divided powdered metallic antinomy immersed in liquid sp3He was measured using pulsed Nuclear Quadrupole Resonance (NQR) techniques. In this technique, the nuclear quadrupole resonant antinomy nuclei were saturated using an RF pulse. The recovery back to equilibrium was monitored using short inspection pulses and the magnetization recovery follows a recovery curve characterized by

Edgar Baylon Genio

1997-01-01

103

Measurements of N.Q.R. apparent spin-spin relaxation times in monochloroacetic acid  

NASA Astrophysics Data System (ADS)

Measurements of T ?2 for monochloroacetic acid in the ?,? and ? phases were made. Major variations in T ?2 values following the ??? and ??? transitions were observed, leading the authors to conclude that these transitions were a source of defects and crystal strains. The results further emphasized the need for describing the history of samples when quoting T ?2 measurements. The observation of T ?2 variations in all three phases highlights the sensitivity of T ?2 measurements to changes in these defects and strains.

McDonald, A. D.; Hacobian, S.

104

Multipulse sequences for explosives detection by NQR under conditions of magnetoacoustic and piezoelectric ringing  

Microsoft Academic Search

A number of methods for cancelling magnetoacoustic and piezoelectric ringing signals in the spectroscopy of the nuclear quadrupole\\u000a resonance are presented. The suggested methods include using the sequence (?0)?-(?-?x-2?-?\\u000a y\\u000a -2?-??x\\u000a -2?-??y\\u000a -?)\\u000a n\\u000a and a multipulse analog of the two-pulse Hahn sequence with the first pulse replaced by a short steady-state sequence. Another\\u000a method presented is the method of

V. T. Mikhaltsevitch; T. N. Rudakov; J. H. Flexman; P. A. Hayes; W. P. Chisholm

2004-01-01

105

Unconventional superconductivity in ferromagnetic UGe2: a 73Ge nuclear magnetic resonance\\/nuclear quadrupole resonance study  

Microsoft Academic Search

We report 73Ge nuclear magnetic resonance\\/nuclear quadrupole resonance (NMR\\/NQR) measurements on the itinerant ferromagnetic superconductor UGe2 at ambient pressure (P = 0) and P = 1.3 GPa. Measurements of the nuclear spin-lattice relaxation rate 1\\/T1 of the 73Ge NMR at P = 0 have revealed a T1T = constant behaviour well below TCurie = 52 K, evidencing the presence of

H. Kotegawa; S. Kawasaki; A. Harada; Y. Kawasaki; K. Okamoto; G.-q. Zheng; Y. Kitaoka; E. Yamamoto; Y. Haga; Y. Onuki; K. M. Itoh; E. E. Haller

2003-01-01

106

Superconductivity and magnetic fluctuations in Cd(2))Re(2)O(7) via Cd nuclear magnetic resonance and re nuclear quadrupole resonance.  

PubMed

We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K. PMID:12097064

Vyaselev, O; Arai, K; Kobayashi, K; Yamazaki, J; Kodama, K; Takigawa, M; Hanawa, M; Hiroi, Z

2002-07-01

107

A theoretical study of 17O, 14N and 2H nuclear quadrupole coupling tensors in the real crystalline structure of acetaminophen  

NASA Astrophysics Data System (ADS)

A systematic computational investigation was carried out to characterize the 17O, 14N and 2H electric field gradient, EFG, tensors in the acetaminophen real crystalline structure. To include the hydrogen bonding effects in the calculations, the most probable interacting molecules with the target molecule in the crystalline phase were considered through the various molecular clusters. The calculations were performed with the B3LYP method and 6-311++G ?? and 6-311+G ? standard basis sets using the Gaussian 98 suite of programs. Calculated EFG tensors were used to evaluate the 17O, 14N, and 2H nuclear quadrupole resonance, NQR, parameters in acetaminophen crystalline structure, which are in good agreement with the available experimental data. The difference between the calculated NQR parameters of the monomer and molecular clusters shows how much hydrogen bonding interactions affect the EFG tensors of each nucleus. These results indicate that both O-H⋯O and N-H⋯O hydrogen bonding have major influence on the NQR parameters. Moreover, the quantum chemical calculation indicated that the intermolecular hydrogen bonding interactions play an essential role in determining the relative orientation of quadrupole coupling principal components in the molecular frame axes.

Behzadi, Hadi; Esrafili, Mehdi D.; Hadipour, Nasser L.

2007-03-01

108

Photodarkening effect in glassy As 2S 3 and As 2O 3  

Microsoft Academic Search

Photodarkening, or the shift of the optical absorption edge to smaller energies after excitation with light whose energy is near that of the optical band edge, has been studied in the chalcogenide glasses for many years. Recently we have conducted high field nuclear magnetic resonance (NMR) studies at 17 T and nuclear quadrupole resonance (NQR) studies of 75As in glassy

P. Hari; S. Guzel; T. Su; P. C. Taylor; P. L. Kuhns; W. G. Moulton; N. S. Sullivan

2003-01-01

109

Low-frequency nuclear quadrupole resonance with a dc SQUID  

SciTech Connect

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.

Chang, J.W.

1991-07-01

110

High precision measurement of the 11Li and 9Li quadrupole moment ratio using zero-field ?-NQR  

NASA Astrophysics Data System (ADS)

The ratio of electric quadrupole moments of 11Li and 9Li was measured using the zero-field ?-detected nuclear quadrupole resonance technique at Triumf-Isac. The precision on the ratio Q11/Q9 = 1.0775(12) was improved by more than one order of magnitude and an absolute value for the quadrupole moment of 11Li was inferred. Systematic effects, as argued here, are not expected to contribute to the ratio on this scale. The zero-field spin-lattice relaxation time for 8Li implanted within SrTiO3 at 295?K in zero-field was found to be T1 = 1.73(2)?s. A comparison of the quadrupole moments of 9, 11Li and their ratio is made with the latest models, however, no conclusion may yet be drawn owing to the size of the theoretical uncertainties.

Voss, A.; Pearson, M. R.; Buchinger, F.; Crawford, J. E.; Kiefl, R. F.; Levy, C. D. P.; MacFarlane, W. A.; Mané, E.; Morris, G. D.; Shelbaya, O. T. J.; Song, Q.; Wang, D.

2014-01-01

111

Nuclear quadrupole resonance. Electronic structure and sterochemistry of halogenonaphthalenones  

SciTech Connect

The /sup 35/Cl NQR spectra of 2-chloro-, 2, 3-dihydro-2-bromo-2,3-dichloro-, and 2,2,3-trichloro-4-diphenyl-methylene-1(4H)-napthalenones (I-III) were studied. The experimental data are compared with the results from quantum-chemical calculations for the conformers of the molecules of (I-III) by the CNDO/2 method. The adequacy of the conformation description of systems (I-III) by the method using the /sup 35/Cl NQR frequencies was established by study of 1,2-dichloroacenaphthene and 2-chlorotetrahydropyran. It was established that compound (II) in the crystal exists in the form of the conformer with the bromine atom in the axial position. The possibilities of using an electrostatic model for the discussion of the conformations of the 2,3-dyhydro derivatives (II) and (III) with separate allowance for the geminal and vicinal environments of the chlorine probe atom are examined.

Romanenko, E.A.; Nesterenko, A.M.; Novikov, V.P.; Kolesnikov, V.T.

1987-11-01

112

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

SciTech Connect

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.

Pollack, L.; Smith, E.N.; Richardson, R.C. [Cornell Univ., Ithaca, NY (United States)

1997-01-01

113

Magnetic field-cycling NMR and 14N, 17O quadrupole resonance in the explosive pentaerythritol tetranitrate (PETN)  

NASA Astrophysics Data System (ADS)

The explosive pentaerythritol tetranitrate (PETN) C(CH 2-O-NO 2) 4 has been studied by 1H NMR and 14N NQR. The 14N NQR frequency and spin-lattice relaxation time T1Q for the ? + line have been measured at temperatures from 255 to 325 K. The 1H NMR spin-lattice relaxation time T1 has been measured at frequencies from 1.8 kHz to 40 MHz and at temperatures from 250 to 390 K. The observed variations are interpreted as due to hindered rotation of the NO 2 group about the bond to the oxygen atom of the CH 2-O group, which produces a transient change in the dipolar coupling of the CH 2 protons, generating a step in the 1H T1 at frequencies between 2 and 100 kHz. The same mechanism could also explain the two minima observed in the temperature variation of the 14N NQR T1Q near 284 and 316 K, due in this case to the transient change in the 14N… 1H dipolar interaction, the first attributed to hindered rotation of the NO 2 group and the second to an increase in torsional amplitude of the NO 2 group due to molecular distortion of the flexible CH 2-O-NO 2 chain which produces a 15% increase in the oscillational amplitude of the CH 2 group. The correlation times governing the 1H T1 values are approximately 25 times longer than those governing the 14N NQR T1Q, explained by the slow spin-lattice cross-coupling between the two spin systems. At higher frequencies, the 1H T1 dispersion results show well-resolved dips between 200 and 904 kHz assigned to level crossing with 14N and weaker features between 3 and 5 MHz tentatively assigned to level crossing with 17O.

Smith, John A. S.; Rayner, Timothy J.; Rowe, Michael D.; Barras, Jamie; Peirson, Neil F.; Stevens, Andrew D.; Althoefer, Kaspar

2010-05-01

114

Magnetic field-cycling NMR and (14)N, (17)O quadrupole resonance in the explosive pentaerythritol tetranitrate (PETN).  

PubMed

The explosive pentaerythritol tetranitrate (PETN) C(CH(2)-O-NO(2))(4) has been studied by (1)H NMR and (14)N NQR. The (14)N NQR frequency and spin-lattice relaxation time T(1Q) for the nu(+) line have been measured at temperatures from 255 to 325K. The (1)H NMR spin-lattice relaxation time T(1) has been measured at frequencies from 1.8kHz to 40MHz and at temperatures from 250 to 390K. The observed variations are interpreted as due to hindered rotation of the NO(2) group about the bond to the oxygen atom of the CH(2)-O group, which produces a transient change in the dipolar coupling of the CH(2) protons, generating a step in the (1)H T(1) at frequencies between 2 and 100kHz. The same mechanism could also explain the two minima observed in the temperature variation of the (14)N NQR T(1Q) near 284 and 316K, due in this case to the transient change in the (14)N...(1)H dipolar interaction, the first attributed to hindered rotation of the NO(2) group and the second to an increase in torsional amplitude of the NO(2) group due to molecular distortion of the flexible CH(2)-O-NO(2) chain which produces a 15% increase in the oscillational amplitude of the CH(2) group. The correlation times governing the (1)H T(1) values are approximately 25 times longer than those governing the (14)N NQR T(1Q), explained by the slow spin-lattice cross-coupling between the two spin systems. At higher frequencies, the (1)H T(1) dispersion results show well-resolved dips between 200 and 904kHz assigned to level crossing with (14)N and weaker features between 3 and 5MHz tentatively assigned to level crossing with (17)O. PMID:20236842

Smith, John A S; Rayner, Timothy J; Rowe, Michael D; Barras, Jamie; Peirson, Neil F; Stevens, Andrew D; Althoefer, Kaspar

2010-05-01

115

Nuclear quadrupole resonance detection of explosives: an overview  

NASA Astrophysics Data System (ADS)

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.

Miller, Joel B.

2011-05-01

116

New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique  

Microsoft Academic Search

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

Vadim S Grechishkin; Nikolai Ya Sinyavskii

1997-01-01

117

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

NASA Astrophysics Data System (ADS)

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

Grechishkin, Vadim S.; Sinyavskii, Nikolai Ya

1997-04-01

118

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

PubMed Central

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

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

2009-01-01

119

Coexistence of Antiferromagnetism with Superconductivity in CePt2In7: Microscopic Phase Diagram Determined by In115 NMR and NQR  

NASA Astrophysics Data System (ADS)

Single crystals of the heavy-fermion antiferromagnet CePt2In7 with a Néel temperature (TN) of 5.2 K at ambient pressure have been investigated by zero-field In115-nuclear magnetic and quadrupole resonance measurements as a function of applied pressure. Within the antiferromagnetic state, the character of Ce's 4f electron appears to change from localized to itinerantlike at P*˜2.4 GPa, approximately the pressure where superconductivity first emerges. With increased pressure, the superconducting transition Tc reaches a maximum just at or slightly before antiferromagnetic order disappears, and not at the pressure Pc˜3.4 GPa, where the steeply decreasing Néel boundary extrapolates to zero temperature. For P >Pc, the spin relaxation rate drops sharply by more than 2 orders of magnitude at Tc, suggestive of a first-order transition.

Sakai, H.; Tokunaga, Y.; Kambe, S.; Ronning, F.; Bauer, E. D.; Thompson, J. D.

2014-05-01

120

On the manifestation of electron-nuclear dynamics in 59Co NQR spectra for the series of ?-cyclopentadienyl-?-(3)-1,2-dicarbollylcobalt derivatives  

NASA Astrophysics Data System (ADS)

The dependence between quadrupole coupling constants and 59Co asymmetry parameters at 77 K was established in the series (?-C5H4X)Co[?-(3)-1,2-B9H8(8-Z)C2HY]. It was shown that a region of the dynamic Opic-Pryce effect can be determined for these compounds.

Semin, G. K.; Bryukhova, E. V.

2010-02-01

121

Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As Nuclear Quadrupole Resonance and Specific Heat  

NASA Astrophysics Data System (ADS)

We report the 75As nuclear quadrupole resonance (NQR) and specific heat measurements of the heavily hole-doped superconductor KFe2As2 (superconducting transition temperature Tc? 3.5 K). The spin-lattice relaxation rate 1/T1 in the superconducting state exhibits a gradual temperature dependence with no coherence peak below Tc. The quasiparticle specific heat CQP/T shows a small jump, which is about 30% of the electronic specific heat coefficient just below Tc. The CQP/T suggests the existence of low-energy quasiparticle excitation at the lowest measurement temperature T=0.4 K? Tc/10. The T dependences of 1/T1 and CQP/T can be explained by a multiple nodal superconducting gap scenario rather than by a multiple fully gapped s±-wave scenario determined using simple gap analysis.

Fukazawa, Hideto; Yamada, Yuji; Kondo, Kenji; Saito, Taku; Kohori, Yoh; Kuga, Kentarou; Matsumoto, Yosuke; Nakatsuji, Satoru; Kito, Hijiri; Shirage, Parasharam M.; Kihou, Kunihiro; Takeshita, Nao; Lee, Chul-Ho; Iyo, Akira; Eisaki, Hiroshi

2009-08-01

122

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.

123

Nuclear quadrupole resonance studies on weak exchange interactions between paramagnetic ions in M(II)(H2O)6SnCl6 (M(II) = Mn, Co, and Ni)  

NASA Astrophysics Data System (ADS)

The 35Cl NQR spin-lattice relaxation times T1Q in paramagnetic Mn(H2O)6SnCl6 and Co(H2O)6SnCl6 crystals were measured as a function of temperature. Using the T1Q values observed, the correlation times ?f of electron-spin flip-flops and exchange parameters J were estimated. The J value in Mn salt was found to be smaller than those found for Co and Ni salts. It is inferred from the J values that the indirect interaction where some chemical bonds (including OH...Cl hydrogen bonds) intervene is dominant in the exchange interactions between the paramagnetic ions in M(II)(H2O)6SnCl6 (M(II) = Mn, Co and Ni).

Miyoshi, Hiroshi; Ikeda, Ryuichi; Koshio, Akira; Horiuchi, Keizo

2002-02-01

124

Nonresonant Photon Dressing in Spin One Quadrupolar Systems  

NASA Astrophysics Data System (ADS)

The main part of this thesis is a study of the effects of nonresonant photon dressing on spin 1 pure quadrupolar system with symmetric EFG. Energy levels of spin 1 nuclei dressed by linearly or circularly polarized photons were theoretically derived and numerically analyzed. In both cases, the degeneracy of m_zeta equals +/-1 states is not lifted, so only one line can be excited and it is shifted up in frequency. The energy levels are found to depend on the angle theta between the principle EFG zeta axis and the dressing field. Since most NQR samples are polycrystalline, a general formula for powder patterns due to photon dressing was derived and numerical examples were plotted for the case of linearly polarized photons, spin 1 and {3over2 }, and circularly polarized photons, spin 1. In all of these cases, NQR lines are broadened, and have a peak located at theta = 90 ^circ. Energy levels of photon dressed protons in zero static field are analyzed for the purpose of discussing ^{14}N^in-echo time. Protons are shown to reorient between +/-{1over2 } states rapidly, so that their local field tends to average out. Powdered crystalline samples Trimethylamine (TMA), Triethylenediamine (TED), and Hexanethylenetetramine (HMT) all with symmetric EFG were experimentally investigated by ^{14}N NQR. For circularly polarized dressing of 25 G peak, no NQR frequency shift was observed; a monotonic line narrowing was observed in TMA and TED, but not HMT; fine structure details of TED and HMT were revealed as a result of the line narrowing, but the cause of the fine structure was not determined. Experimental results are in good agreement with theory. A minor portion of this thesis is to study the effects of annealing and hydrogenation on short-range order in amorphous III-V compounds through NMR linewidth. alpha - GaP, alpha - GaAs, and alpha - GaAs: H grown on single crystal alkali halide substrates by rf-sputtering have been studied. The results were compared with that of previous measurements on alpha - GaP and alpha - GaAs grown on different substrates at different temperature. The study showed that sample microstructure is directly influenced by sample preparation conditions, however, the presence of 10% hydrogen in the sample did not influence the NMR linewidth at room temperature nor the annealing behavior.

Zhuang, Yi-Li.

125

Proton dynamics in one-dimensional hydrogen-bonding system in molecular co-crystals TMP-D2ca and DMP-H2ca  

NASA Astrophysics Data System (ADS)

The proton dynamics in one-dimensional hydrogen-bonding system in molecular co-crystals of tetramethylpyrazine (TMP) with chloranilic acid (H2ca), as well as 2,6-dimethylpyrazine (DMP) with H2ca is studied by 35Cl NQR and 2H NMR spin-lattice relaxation measurements. No transfer motion of proton between the acid and base molecules is observed in DMP-H2ca, while the motion of the acid proton is excited in TMP-H2ca and the activation energy for the motion increases from 35 kJ mol - 1 to 50 kJ mol - 1 by the deuteration.

Asaji, T.; Amino, D.; Tago, N.; Mizuno, M.

2010-04-01

126

Peace Studies.  

ERIC Educational Resources Information Center

Themes that should be included in an elementary and secondary peace studies curriculum are discussed in this newsletter essay. Social studies teachers must use great discretion as to what topics in the peace studies curriculum are taught at what level. The study of nuclear arms should be included in peace studies at the secondary level. Research…

Perrone, Vito

1986-01-01

127

Funded Studies  

Cancer.gov

Funded Studies To date, 34 studies have been funded as part of the BIQSFP program: Type of Study FY Approved Integral/ Integrated Coop Group/ CCOP Study Number Phase Concept Title Cancer Site Biomarker 2014 Integral Alliance A071102 II-III

128

Biofeasibility Study.  

ERIC Educational Resources Information Center

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)

Chaparian, Michael

1995-01-01

129

Intelligence Studies  

ERIC Educational Resources Information Center

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…

Monaghan, Peter

2009-01-01

130

College Studying.  

ERIC Educational Resources Information Center

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…

Nist, Sherrie L.; Simpson, Michele

2002-01-01

131

35 C1 nor spectra for crystalline forms of monochloroacetic acid  

Microsoft Academic Search

thermocouple calibrated from the temperature dependence of the ~ssCl NQR line in KCI03 (5), and in the second, by a thermometer. The tempera- tures were maintained and measured toK, while the relative error in measuring the NQR fre- quency was 0.01% in all cases, apart from the ~ phase near the second-order phase transition (see below), where the NQR lines

1988-01-01

132

Image restoration using fast Fourier and wavelet transforms  

NASA Astrophysics Data System (ADS)

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.

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

1994-02-01

133

Narcotics and explosives detection by 14N pure nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

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.

Garroway, Allen N.; Buess, M. L.; Yesinowski, J. P.; Miller, J. B.

1994-03-01

134

Studying Abroad  

NSDL National Science Digital Library

Recently unveiled by UNESCO, this site is designed to serve as a resource for students considering studying abroad at institutions of higher education, university community members, Secretariats of Regional Committees, and other interested parties. At present, much of the site is under construction, but it does offer an electronic version of Study Abroad, UNESCO's massive guide to higher-education study opportunities and scholarships. The guide totals 629 pages and includes 2,659 entries on courses and scholarships in different higher-education academic and professional disciplines in 129 countries. Anyone interested in studying abroad will want to take a look at this guide and monitor the site for future developments.

2001-01-01

135

Social Studies.  

ERIC Educational Resources Information Center

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

White, Cam, Ed.

136

Case Studies  

Microsoft Academic Search

This study was designed to document the effect that wet abrasive blasting has on reducing worker exposure to crystalline silica, which has been associated with silicosis and premature death. In this study, worker exposure to respirable crystalline silica was monitored during wet abrasive blasting on the exterior walls of a parking garage to remove surface concrete and expose the underlying

Lawrence Mazzuckelli; Vijay Golla; William Heitbrink

2004-01-01

137

Observational Studies  

NSDL National Science Digital Library

This lesson on observational studies discusses the nature of such studies, the relationships between various data sets, and regression. Graphs illustrate the relationships, and exercises at the end test the user's comprehension and understanding. It is taken from the online textbook for Western Michigan University online introductory stats course.

Abebe, Asheber; Daniels, John E.; Kapenga, J. A.; Mckean, Joe W.

2008-12-25

138

Stream Study  

NSDL National Science Digital Library

The Stream Study provides a method to determine the water quality of a stream based on the collection and identification of stream-bottom macroinvertebrates. The site includes a catalog of common stream macroinvertebrates and a glossary of terms used to study streams.

Bull, Glenn; Deviney, Frank; Firehock, Karen; Rivers, Barbara; Webb, Susan

1999-03-01

139

Study Stack  

NSDL National Science Digital Library

Developed by John Weidner, the Study Stack concept basically assists individuals to memorize information about various subjects, including geography, history, math, languages, and science. Users of the site can select one of the existing stacks, which consists of virtual study cards allowing individuals to learn at their own pace until they are satisfied with their progress. What is also particularly novel about this learning tool is that data entered for customized study stacks can be automatically displayed as a matching game, a word search puzzle, or a hangman game. So far, the site contains dozens of study stacks for each subject, with the areas dedicated to math and science containing quite a number of rather helpful stacks. With its wide range of applications, this site will be very helpful to students at different age levels and teachers who may be seeking to develop a new study tool for any number of topics or themes within a subject area.

Weidner, John

140

ME-Burg Muon-spin-rotation Study of (Pr,Y)BCO: Pr in BaO layer?!  

NASA Astrophysics Data System (ADS)

Muon-spin-rotation data of polycrystalline Pr(x)Y(1-x)BCO (0 < x < 1) recorded at 1-kOe transverse fields and room temperature (RT) have been analyzed by a Maximum-Entropy (ME) Burg technique. The obtained magnetic field distributions for different Pr doping show distinct differences just below the applied field. This is inconsistent with the assumption that all Pr ions are at the rare-earth sites. NQR has suggested direct evidence of some Pr occupation of the Ba sites. [1] At RT, the muon locally probes among the Balmer sites located between the BaO and CuO-chain layers. [2] Because of charge neutrality, Ba-site occupation by Pr requires an extra negative O ion at a nearby vacancy site. These atomic changes lead to differences in the muon environment, and can explain the variations seen in the ME-Burg transforms. These magnetic field distributions have been fitted using two Lorentzians affirming consistent trends seen for the (x < 0.5) superconductors. A magnetic presence of Pr in the BaO layer may explain the disappearance of superconductivity for PrBCO. Research is supported by NHMFL, NSF-REU, DOE-LANL and WiSE@SJSU. 1] A. P. Reyes, M. M. Abdelrazek et al, M2S-HTSC-VI Conf Proc, Physica C (2000). 2] W. K. Dawson et al, Hyperfine Interactions 63 (1990) 219.

Aslanian, H. H.; Tun, M.; Abdelrazek, M. M.; Cavanaugh, S. X.; Boekema, C.

2001-03-01

141

Polarization study.  

National Technical Information Service (NTIS)

Brief review is presented of the high energy polarization study including experimental data and the theoretical descriptions. The most important proposals at the biggest accelerators and the crucial technical developments are also listed which may become ...

S. B. Nurushev

1989-01-01

142

Sleep Studies  

MedlinePLUS

... Clinical Trials Links Related Topics Sleep Apnea CPAP Narcolepsy Sleep Deprivation and Deficiency Related Media Videos Widgets ... your doctor find out whether you have a sleep disorder and how severe it is. Sleep studies are ...

143

Zoning Study.  

National Technical Information Service (NTIS)

The study analyzes existing zoned properties in the Shreveport Standard Metropolitan Statistical Area to determine if current development justifies the amount of such zoning. It reviews administrative procedures and policies used in carrying out zoning ch...

1968-01-01

144

Phase transition and temperature dependent electronic state of an organic ferroelectric, phenazine chloranilic acid (1:1)  

NASA Astrophysics Data System (ADS)

The isotope effect of hydrogen motion in an organic ferroelectric, phenazine (Phz)-chloranilic acid (H2ca and D2ca for normal and deuterated compounds, respectively) co-crystal, was studied by 35Cl nuclear quadrupole resonance (NQR). Besides a ferroelectric transition at Tc = 253 K (303 K), a neutral-to-ionic transition was found below 170 K (200 K) for Phz-H2ca (Phz-D2ca). 1H-14N nuclear quadrupole double resonance measurements were also made in order to study the temperature dependent electronic state of Phz-(H/D)2ca. 14N NQR parameters suggested that donor orbital populations of the two nitrogen atoms in a phenazine molecule become nonequivalent (1.78 and 1.97) in the ferroelectric phase, while they are both equal to 1.89 in the paraelectric phase. In the ionic phase of Phz-D2ca, which was obtained by cooling below 188 K, they became 1.50 and 1.95, suggesting a proton transfer from D2ca to Phz.

Asaji, T.; Seliger, J.; Zagar, V.; Sekiguchi, M.; Watanabe, J.; Gotoh, K.; Ishida, H.; Vrtnik, S.; Dolinšek, J.

2007-06-01

145

Visibility Studies  

NASA Technical Reports Server (NTRS)

Studies conducted by the Environmental Studies Laboratory of the University of Utah embrace investigations of the effects of air pollutants on vegetation; air quality in arid and semi-arid regions surrounding energy developments; and the amount, size and type of particles in the atmosphere. In its visibility studies, the laboratory uses a computer program called RADTMO for Radiative Transfer Models. The program computes the characteristics of scattered radiation in the atmosphere including ozone concentration and aerosol density at various altitudes. Calculations provide information used in determining sky color intensity for visibility modeling under different atmospheric conditions. The laboratory was able to avoid the cost of developing a new computer program by using RADTMO for their calculations.

1982-01-01

146

CREOLE STUDIES.  

ERIC Educational Resources Information Center

THE AUTHOR FEELS THAT THE STUDY OF THE CREOLIZATION OF LANGUAGE IN THE CARIBBEAN AREA IS IMPORTANT TO LINGUISTS, LANGUAGE TEACHERS, AND SOCIOLINGUISTS IN ALL PARTS OF THE WORLD. IN THIS PAPER, PRESENTED AT THE SECOND INSTITUTE OF THE INTER-AMERICAN PROGRAM IN LANGUAGES AND LINGUISTICS (MEXICO CITY, FEBRUARY 1968), HE FIRST REPORTS ON WORK DONE AT…

FIGUEROA, JOHN J.

147

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...

148

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...

149

Cholera studies*†  

PubMed Central

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.

Pollitzer, R.; Burrows, W.

1955-01-01

150

Readability Study.  

ERIC Educational Resources Information Center

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

White, Robert; Jordan, William

151

NMR reveals double occupancy of quinone-type ligands in the catalytic quinone binding site of the Na+-translocating NADH:Quinone oxidoreductase from Vibrio cholerae.  

PubMed

The sodium ion-translocating NADH:quinone oxidoreductase (Na(+)-NQR) from the pathogen Vibrio cholerae exploits the free energy liberated during oxidation of NADH with ubiquinone to pump sodium ions across the cytoplasmic membrane. The Na(+)-NQR consists of four membrane-bound subunits NqrBCDE and the peripheral NqrF and NqrA subunits. NqrA binds ubiquinone-8 as well as quinones with shorter prenyl chains (ubiquinone-1 and ubiquinone-2). Here we show that the quinone derivative 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), a known inhibitor of the bc1 and b6f complexes found in mitochondria and chloroplasts, also inhibits quinone reduction by the Na(+)-NQR in a mixed inhibition mode. Tryptophan fluorescence quenching and saturation transfer difference NMR experiments in the presence of Na(+)-NQR inhibitor (DBMIB or 2-n-heptyl-4-hydroxyquinoline N-oxide) indicate that two quinone analog ligands are bound simultaneously by the NqrA subunit with very similar interaction constants as observed with the holoenzyme complex. We conclude that the catalytic site of quinone reduction is located on NqrA. The two ligands bind to an extended binding pocket in direct vicinity to each other as demonstrated by interligand Overhauser effects between ubiquinone-1 and DBMIB or 2-n-heptyl-4-hydroxyquinoline N-oxide, respectively. We propose that a similar spatially close arrangement of the native quinone substrates is also operational in vivo, enhancing the catalytic efficiency during the final electron transfer steps in the Na(+)-NQR. PMID:24003222

Nedielkov, Ruslan; Steffen, Wojtek; Steuber, Julia; Möller, Heiko M

2013-10-18

152

OPEN Study  

Cancer.gov

Over the course of the study, OPEN participants completed 2 Food Frequency Questionnaires (FFQ), 2 24-recall interviews, and filled out several other health-related questionnaires. They were dosed with doubly labeled water (a biomarker used for measuring energy expenditure), provided several spot urine samples to complete the doubly labeled water assessment, completed two 24-hour urine collections and had their height and weight measured.

153

Cholera studies*  

PubMed Central

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.

Pollitzer, R.

1956-01-01

154

Cholera studies*  

PubMed Central

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

Swaroop, S.; Pollitzer, R.

1955-01-01

155

Quaternary Studies  

NSDL National Science Digital Library

First, the Irish Quaternary Association (IQUA) website publicizes its aim "to promote Quaternary studies in Ireland through its publications, and the organization of field meetings and conferences" (1). Visitors can learn about the importance of quaternary studies as well as find out the latest news and upcoming meetings. At the second website, the University of Wisconsin-Madison describes the current and recent studies dealing with "basic and applied problems in glacial geology, surficial geology, palynology, sedimentology, geologic mapping, hydrogeology, soils, and environmental geology "(2). The website offers abstracts of publications of members of the Department of Geology and Geophysics and the Wisconsin Geological and Natural History Survey along with descriptions of the lab, a shaded relief map of the Wisconsin area, and amusing glacial songs. Next, the Godwin Institute of Quaternary Research (GIQR) presents the University of Cambridge's history in quaternary research and the seven current research groups and four recent research projects (3 ). The website furnishes news from the research groups, a gallery of historical images of the East Anglia excursion, and summaries of the Institute's reference collections. Fourth, the International Union for Quaternary Research (INQUA) discusses quaternary scientists' investigations "to interpret the changing world of the glacial ages and their impact on our planet's surface environments" (4). Researchers can find out about INQUA-funded projects, meetings, and scientific commissions. Next, the Quaternary Research Association explains that it "exists to promote understanding of the Quaternary Period by publishing field guides, technical guides, and an international journal as well as holding field meetings and speaker meetings" (5). Students and researchers can discover employment, research, grant, meetings, and educational opportunities. Sixth, the University of Wales presents its investigations in the Remote Sensing Laboratory, Palaeoecology Laboratory, and the Luminescence Laboratory (6 ). Users can find concise descriptions of individual researchers' successes, abstracts of published papers, and links to conference information. The seventh website illustrates the Alaska Quaternary Center's commitment "to the promotion of interdisciplinary research and the enhancement of interdisciplinary instruction in Quaternary sciences" (7). Users can view images of the field work and learn how to obtain quaternary data from the Geographic Information Network of Alaska (GINA). Lastly, Rutgers University promotes its Graduate Certificate in Quaternary Studies where students take part in geology, geography, meteorology, and other disciplines interested in the last couple of million years of Earth's history (8). Students and educators can find information on the researchers involved with the program and the necessary course work.

156

Plague studies*  

PubMed Central

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.

Pollitzer, R.

1953-01-01

157

Plague studies*  

PubMed Central

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.

Pollitzer, R.

1953-01-01

158

Nutritional studies  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

159

Cholera studies*  

PubMed Central

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.

Pollitzer, R.

1957-01-01

160

Limiter study  

SciTech Connect

Studies of energy deposition on a mushroom-shaped limiter have been performed on ZT-40M. Total energy deposition, estimated power deposition per unit area, the effects of gas puffing and vertical and error field application, and approximate time histories of the extent of the impact area are presented for two different current levels (120 and 190 kA), protrusions into the body of the plasma (+2 - +12 mm from the wall) and limiter materials. Photographs of a bare graphite and TiC-coated graphite limiter before and after exposure to the plasma are shown. Massive spallation of the TiC-coated limiter is observed at the higher current level. Spallation occurs during the discharge and after termination. The degree of spallation is dependent on the current level. The average power deposition on the limiter over the discharge is estimated to be less than or equal to 1 MW.

Downing, J.N.; Gordon, R.A.; Thomas, K.S.; Watt, R.G.

1983-08-01

161

Cholera studies*  

PubMed Central

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.

Pollitzer, R.

1957-01-01

162

Astrophysical Studies  

NASA Astrophysics Data System (ADS)

Research was carried out in the following areas: (1) structure of molecular clouds: Bertoldi (in collaboration with C.F. McKee) investigated the structure of molecular clouds. Bertoldi & McKee (1992) conclude that many of the clumps in molecular clouds are actually pressure-confined. Only the more massive clumps are self-gravitating; the most massive of these are 'magnetically supercritical' (i.e., cannot be supported by magnetic pressure alone) and require generation of internal turbulence to support them. (2) Structure of HII regions: Bertoldi (in collaboration with E.B. Jenkins) investigated the implications of IMAPS ultraviolet observations of absorption toward pi-Sco by NII ions in the excited fine structure levels. The observed absorption indicates surprisingly high pressure in the region where the excited NII is located. Bertoldi and Jenkins (1992) concluded that this high-pressure 'clump' is probably a photoevaporating outflow from a protoplanetary disk around a low mass star. They argued that there are likely to be large numbers of such systems in the neighborhood of pi-Sco, presumably a gravitationally bound star cluster of which pi-Sco is the only bright member. (3) PAH molecules -- Charging and Photoelectric Heating: Bakes & Tielens (1994ab) studied the charging of PAH molecules by photoelectric emission and collisions with electrons, and evaluated the heating of the interstellar gas due to the photoelectric emission. They concluded that if PAH's are present in the ISM with the abundances required to explain the UIR emission bands, then the photoelectric heating by PAH's should be the dominant heating process in diffuse clouds and in photodissociation regions. The resulting rates of photoelectric heating by PAH's and small grains were used to study the thermal equilibrium of gas in photodissociation fronts illuminated by cool stars (Spaans et al. 1994), and the thermal equilibrium of interstellar gas (Wolfire et al. 1995). Publications supported by this grant are listed.

Draine, Bruce T.

1996-02-01

163

The role of glycine residues 140 and 141 of subunit B in the functional ubiquinone binding site of the Na+-pumping NADH:quinone oxidoreductase from Vibrio cholerae.  

PubMed

The Na(+)-pumping NADH:quinone oxidoreductase (Na(+)-NQR) is the main entrance for electrons into the respiratory chain of many marine and pathogenic bacteria. The enzyme accepts electrons from NADH and donates them to ubiquinone, and the free energy released by this redox reaction is used to create an electrochemical gradient of sodium across the cell membrane. Here we report the role of glycine 140 and glycine 141 of the NqrB subunit in the functional binding of ubiquinone. Mutations at these residues altered the affinity of the enzyme for ubiquinol. Moreover, mutations in residue NqrB-G140 almost completely abolished the electron transfer to ubiquinone. Thus, NqrB-G140 and -G141 are critical for the binding and reaction of Na(+)-NQR with its electron acceptor, ubiquinone. PMID:22645140

Juárez, Oscar; Neehaul, Yashvin; Turk, Erin; Chahboun, Najat; DeMicco, Jessica M; Hellwig, Petra; Barquera, Blanca

2012-07-20

164

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...

165

Peptide backbone orientation and dynamics in spider dragline silk and two-photon excitation in nuclear magnetic and quadrupole resonance  

NASA Astrophysics Data System (ADS)

In the first part of the dissertation, spider dragline silk is studied by solid state NMR techniques. The dependence of NMR frequency on molecular orientation is exploited using the DECODER experiment to determine the orientation of the protein backbone within the silk fibre. Practical experimental considerations require that the silk fibres be wound about a cylindrical axis perpendicular to the external magnetic field, complicating the reconstruction of the underlying orientation distribution and necess-itating the development of numerical techniques for this purpose. A two-component model of silk incorporating static b-sheets and polyglycine II helices adequately fits the NMR data and suggests that the b-sheets are well aligned along the silk axis (20 FWHM) while the helices are poorly aligned (68 FWHM). The effects of fibre strain, draw rate and hydration on orientation are measured. Measurements of the time-scale for peptide backbone motion indicate that when wet, a strain-dependent frac-tion of the poorly aligned component becomes mobile. This suggests a mechanism for the supercontraction of silk involving latent entropic springs that undergo a local strain-dependent phase transition, driving supercontraction. In the second part of this dissertation a novel method is developed for exciting NMR and nuclear quadrupole resonance (NQR) by rf irradiation at multiple frequencies that sum to (or differ by) the resonance frequency. This is fundamentally different than traditional NMR experiments where irradiation is applied on-resonance. With excitation outside the detection bandwidth, two-photon excitation allows for detection of free induction signals during excitation, completely eliminating receiver dead-time. A theoretical approach to describing two-photon excitation is developed based on average Hamiltonian theory. An intuition for two-photon excitation is gained by analogy to the coherent absorption of multiple photons requiring conservation of total energy and momentum. It is shown that two-photon excitation efficiency impro-ves when the two applied rf frequencies deviate from half-resonance. For two-photon NQR, it is shown that observable magnetization appears perpendicular to the excita-tion coil, requiring a second coil for detection, and that double quantum coherences are also generated. Several model systems and experimental geometries are used to demonstrate the peculiarities of two-photon excitation in NMR and NQR.

Eles, Philip Thomas

166

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 ...

167

Science and Technology Studies and Information Studies.  

ERIC Educational Resources Information Center

Reviews the literature of the field of Science and Technology Studies (STS) and describes its relevance to Information Studies (IS). Workplace studies, key themes, the use of STS in IS research, and implications of STS for IS are also covered. (Contains 194 references.) (MES)

Van House, Nancy A.

2004-01-01

168

Ferromagnetic and Triplet-Pairing Instabilities Controlled by Trigonal Distortion of CoO6 Octahedra in NaxCoO2\\cdotyH2O  

NASA Astrophysics Data System (ADS)

In the recently discovered Co-oxide superconductor NaxCoO2\\cdotyH2O, the edge-shared CoO6 octahedra are trigonally contracted along the c-axis in the CoO2-plane. We study how this CoO6 distortion affects the magnetic properties and superconductivity in this compound by analyzing the multiorbital Hubbard model using the fluctuation-exchange approximation. It is shown that through generating the trigonal crystal field, the distortion pushes the Co {e}\\primeg bands up and consequently gives rise to the hole-pocket Fermi surfaces, which have been predicted in the band calculations. As the distortion increases, the hole pockets are enlarged and the ferromagnetic fluctuation as well as the pairing instability increases, which is in good agreement with recent NQR results.

Mochizuki, Masahito; Yanase, Youichi; Ogata, Masao

2005-06-01

169

Recent Advances in the 5f-Relevant Electronic States and Unconventional Superconductivity of Actinide Compounds  

NASA Astrophysics Data System (ADS)

Recent advances in the understanding of the 5f-relevant electronic states and unconventional superconducting properties are reviewed in actinide compounds of UPd2Al3, UPt3, URu2Si2, UGe2, and PuRhGa5. These are based on the experimental results carried out on high-quality single crystal samples, including transuranium compounds, which were grown by using combined techniques. The paring state and the gap structure of these superconductors are discussed, especially for the corresponding Fermi surfaces which were clarified by the de Haas-van Alphen experiment and the energy band calculations. A detailed systematic study using the NQR/NMR spectroscopy reveals the d-wave superconductivity in PhRhGa5 and the difference of magnetic excitations due to the difference of ground states in U-, Np-, and Pu-based AnTGa5 (T: transition metal) compounds.

Haga, Yoshinori; Sakai, Hironori; Kambe, Shinsaku

2007-05-01

170

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

NASA Astrophysics Data System (ADS)

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.

Hasegawa, Yasumasa

2003-10-01

171

Low pressure phase diagram of CeCoGe3  

NASA Astrophysics Data System (ADS)

We have performed measurements of the Hall magnetization and electrical resistivity on a pressure-induced antiferromagnetic heavy fermion superconductor CeCoGe3 at pressures up to ~1.7 GPa, which crystallizes in the tetragonal BaNiSn3-type structure without inversion symmetry. We have clarified that five successive phase transitions appear at ambient pressure. As pressure is applied, these transitions approach one another until ~1.2 GPa, and then separate again. We have also found another phase transition emerges above ~0.5 GPa, which is consistent with a recent Co-NQR study. From these results, we propose a low pressure P-T phase diagram, which contains at least eight ordered phases below ~2 GPa. This phase diagram is consistent with a recent reported high pressure phase diagram.

Mizoo, Masakazu; Nishioka, Takashi; Kato, Harukazu; Matsumura, Masahiro

2011-01-01

172

High-field 127I NMR of solid sheelite structures: periodates revisited.  

PubMed

We report new solid-state 127I NMR results for sheelite periodates, MIO4 (M = Na+, K+, Rb+, and NH4+), and for pseudo-scheelite CsIO4 and HIO4. The observed 127I quadrupole coupling constants were between 1.0 and 43.0 MHz in agreement with previous NQR data. In contrast to an early 127I NMR study (S. L. Segel and H. M. Vyas, 1980, J. Chem. Phys. 72, 1406), we found that the 127I chemical shift anisotropy is negligibly small in sheelite periodates. A small but definite 127I chemical shift tensor was observed for pseudo-scheelite CsIO4. PMID:11846233

Wu, G; Dong, S

2001-01-01

173

NMR Studies of magnetism and unconventional superconductivity in CeMIn_5  

NASA Astrophysics Data System (ADS)

We report the novel interplay between magnetism and superconductivity in CeMIn5 that forms in a tetragonal structure, focusing on spin dynamics probed by In-NQR measurement via the nuclear spin lattice relaxation rate (1/T_1). At the normal state of CeIrIn5 (T_c=0.4 K) and CeCoIn5 (T_c= 2.1 K), 1/T1 is strongly T-dependent, which indicates that both are much more itinerant than known Ce-based heavy-fermion superconductors. We find that 1/T_1T follows a [1/(T+?)]^3/4 variation with the respective ?=8 and 0.5 K. This novel feature points to anisotropic, due to a layered crystal structure, spin fluctuations near a magnetic ordering. Remarkably, as the system approaches the magnetic critical point at ?=0, a Tc seems to be more enhanced up to 2.1 K for CeCoIn5 rather than for CeIrIn5 [1,2]. In the superconducting (SC) state, 1/T1 follows a T^3 variation without the coherence peak, suggesting unconventional superconductivity with line-node gap. In the itinerant helical magnet CeRhIn_5, we found that the Néel temperature TN is reduced at P > 1.23 GPa with an emergent pseudogap behavior [3,4]. The coexistence of magnetism and superconductivity is found in a narrow P range of 1.63 - 1.75 GPa [5], followed by the onset of SC state with line-node gap at pressures exceeding a value of P=2.1 GPa [3,6]. By contrast, in CeIn3 that forms in a cubic structure, the localized magnetic character is robust against the application of pressure up to P=1.9 GPa, beyond which the system evolves into an itinerant regime in which the resistive SC phase emerges [4]. We discuss the relationship between the phase diagram and the magnetic fluctuation. [1] G. -q. Zheng et al., Phys. Rev. Lett. 86, 4664 (2001). [2] Y. Kawasaki et al., unpublished. [3] T. Mito et al., Phys. Rev. B 63, 220507(R) (2001). [4] S. Kawasaki et al., to appear in Phys. Rev. B in January, 2002. [5] T. Mito et al., unpublished. [6] Y. Kohori et al., Eur. Phys. J. B 18, 601 (2000).

Kitaoka, Yoshio

2002-03-01

174

Magnetic and quadrupole resonance studies of high-T(c) cuprates  

NASA Astrophysics Data System (ADS)

The 63,65Cu NQR spectrum has been measured as a function of Pr doping (x) in the material Y1-xPrxBa 2Cu3O7-delta (x = 0--1.0) at 300K. The chain copper, Cu(1), spectrum showed anomalous peaks as the Pr content increased, while the quadrupolar resonance frequency, nuQ, decreased with x. Point dipole electric field gradient (EFG) simulations performed for all Cu sites point towards the occupation of a new oxygen site, O(5), as the cause for the newly observed peaks in the Cu(1) spectrum. Oxygen deficiency simulations were also performed and cannot account for the anomalous peak seen in the Cu(1) spectrum. 17O NMR at 9T, 13T, 23T, 37T, and 42T has also been measured in NdBa2Cu3O7-delta for both apical and planar oxygen sites. The spin Knight shift for the planar oxygen sites, O(2,3), is smaller than its counterpart in YBCO. We speculate this maybe due to less superconducting carriers in NdBCO. The spin Knight shift of the apical oxygen, O(4), sites is far larger than the value reported in the parent compound, YBCO, and we speculate this may be due to enhanced polarization on the O(4) site, though we are unsure why. The spin-lattice relaxation rate, 1/T1, has also been measured as a function of temperature and is roughly two orders faster than those of YBCO. Moreover, 1/T1 shows a peak at 20K at 9T that shifts to higher temperatures as the field is increased, along with the suppression of this peak with increasing field. The relaxation mechanism in this system has been attributed to the fluctuations of the Nd-moments on the rare earth (RE) site and the enhanced Cu-Cu antiferromagnetic fluctuations. The temperature dependence of the spin-spin relaxation rate, 1/T 2 has been measured at low fields. The onset of vortex "freezing" is observed at low temperatures, while at higher temperatures, the vortices are in the liquid state. The vortex freezing occurs at a lower temperature than in YBCO, but is consistent with samples that have more defects. One possible reason for the increased defects could be Nd-substituted Ba sites, which act as point defects and pinning centers.

Abdelrazek, Margie Mahmoud

175

Nuclear quadrupole resonance of boron in borate glasses  

NASA Astrophysics Data System (ADS)

A continuous wave nuclear quadrupole resonance spectrometer that has a high sensitivity even at low frequencies has been built. Boron and aluminum NQR has been detected in the region 200 kHz to 1.4 MHz. For the first time, boron NQR has been detected in a glass. The NQR spectrum of pure B 20 3 glass is consistent with 85 ± 2% of the boron atoms belonging to boroxol rings. In sodium borate glasses, the number of borons in boroxol rings decreases with increasing sodium content, until when sodium oxide comprises 20 mol% of the glass less than 2% of the borons are in boroxol rings.

Gravina, Samuel J.; Bray, Phillip J.

176

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

PubMed

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

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

2011-12-01

177

Coordination of Cu(II) to lipophilic bis-hydroxamate binders as studied by one- and two-dimensional electron spin echo spectroscopy  

SciTech Connect

The binding of Cu(II) to a lipophilic bis-hydroxamate binder, RL252, and its parent RL239, was investigated by pulsed EPR. The binders have two arms, each terminated with a hydroxamate group which serves as a donor. The major difference between RL252 an RL239 is the absence of the leucine amino acid bridge in RL239. Orientation-selective electron spin echo envelope modulation (ESEEM) experiments were carried out at 8.45 and 9.15 GHz. The spectra obtained were exceptionally well resolved and indicated that the cancellation condition, which requires that the hyperfine coupling is approximately twice the nuclear Larmor frequency, is met at 8-9 GHz. The spectra of both Cu-RL252 and Cu-RL239 showed the nuclear quadrupole resonance (NQR) frequencies, v{sub o}, v{sub -}, and v{sub +}, of the {sup 14}N of the hydroxamate groups at 1.6-1.7, 2.15-2.25, and 3.8-3.9 MHz. A peak corresponding to the double quantum transition in the `noncanceled manifold` v{sub DQ}, was observed at 5-5.2 MHz, and at some magnetic fields a peak corresponding to a single quantum transition, v{sub SQ}, and its combination harmonic appeared as well. The assignment of all the ESEEM frequencies was achieved by the application of the two-dimensional hyperfine sublevel correlation (HYSCORE) experiment. Following the assignment, simulations of the orientation-selective ESEEM spectra were performed, yielding the magnitude and orientation of the quadrupole and hyperfine tensors of the coupled nitrogens. 52 refs., 9 figs., 3 tabs.

Kofman, V.; Shane, J.J.; Goldfarb, D. [Weizmann Inst. of Science, Rehovot (Israel); Dikanov, S.A. [Weizmann Inst. of Science, Rehovot (Israel)]|[Pacific Northwest Lab., Richland, WA (United States); Bowman, M.K. [Pacific Northwest Lab., Richland, WA (United States); Libman, J.; Shanzer, A. [Inst. of Chemical Kinetics and Combustion, Novobirsk (Russian Federation)

1995-12-27

178

Social Studies, Urban Studies, and Ekistics  

ERIC Educational Resources Information Center

A high school-level course utilizing a model from Constantine A. Doxiadis' study, Ekistics: The Science of Human Settlements, is discussed. The model is interdisciplinary and can be adapted for a wide variety of teaching techniques and social studies curricula. (Author/MB)

Surgal, Joel R.; Yashon, Julius R.

1971-01-01

179

Electrodynamic Tether System Study: Extended Study.  

National Technical Information Service (NTIS)

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...

1988-01-01

180

Clinical Nursing Records Study.  

National Technical Information Service (NTIS)

Study assigned as part of the FY 84 AMEDD Study Program; examined inpatient nursing documentation issues, testing new documentation forms and concepts. The study purposes were twofold: assess AMEDD nursing documentation system to identify specific problem...

M. R. Bell P. Twist T. R. Misener

1991-01-01

181

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

182

Collaborative Ocular Melanoma Study (COMS). Study Forms.  

National Technical Information Service (NTIS)

The Collaborative Ocular Melanoma Study (COMS) is a multicenter investigation designed to evaluate therapeutic interventions for patients who have choroidal melanoma. Two randomized controlled trials are currently being conducted. Eligible patients for th...

1991-01-01

183

Advanced planetary studies  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

184

Methodology in Black Studies  

ERIC Educational Resources Information Center

The author suggest six methods of approaching Black Studies: (1) study of the contributions of Africans to world culture; (2) study of the influences of African culture on white culture; (3) interdisciplinary study; (4) research designed to test a hypothesis; (5) use of the novel as a teaching tool; and (6) use of historical materials in the…

Bryant, Henry A., Jr.

1975-01-01

185

Communication Studies, Cultural Studies, and Media Studies Infobase  

NSDL National Science Digital Library

Mick Underwood's extensive infobase of communication, culture, and media studies introduces various models and theories of communication and explains their social and cultural implications. In addition, the infobase includes a detailed index of terms, a bibliography of references, a list of links, a message forum, a chat room, and a series of online quizzes. The great volume of information at this site is effectively managed via several navigation tools: a site map, an index, pull-down menus, and meaningful icons.

186

The National Children's Study  

NSDL National Science Digital Library

The National Children's Study is an ongoing study by the National Institute of Child Health and Human Development, the National Institute of Environmental Health Sciences, the Centers for Disease Control and Prevention, and the US Environmental Protection Agency. This new Web siteprovides comprehensive information about the study, including background, an overview of the study, information from previous meetings, and a list of people involved in coordinating and conducting the study.

2001-01-01

187

Electrodynamic tether system study: Extended study  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

188

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

PubMed

A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary motional conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow motion theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000)] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion models. The two latter models account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow motion spectra to the mechanism of the motional processes modulating the nuclear quadrupole interaction is discussed. PMID:22168707

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

2011-12-14

189

The two-frequency nuclear quadrupole resonance for explosives detection  

Microsoft Academic Search

The two-frequency nuclear quadrupole resonance (NQR) of14N nuclei is described for purposes of explosives detection. Two applications are known: two-frequency NQR for increasing the\\u000a signal intensity, two-frequency NQR for improved reliability of explosives detection. The two-frequency experiments were carried\\u000a out in hexahydro-1,3,5-trinitro-s-triazine C3H6N6O6 and sodium nitrite NaNO2 as a substitute for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocycine C4H8N8O8. The two-frequency sequences for NQR are proposed

G. V. Mozjoukhine

2000-01-01

190

Orbital electronegativities and the determination of s and d hybridization in various halides from nuclear quadrupole resonance frequencies  

Microsoft Academic Search

The use of Orbital Electronegativities in the interpretation of NQR results for various halides is discussed, and an attempt to determine the amount of d hybridization in s and p bonding is made. The ionic characters are assessed.

M. A. Whitehead; H. H. Jaffé

1963-01-01

191

Habitat Study. Transect Study. [Environmental Education Units.  

ERIC Educational Resources Information Center

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.…

Minneapolis Independent School District 275, Minn.

192

STUDY CARRELS, DESIGNS FOR INDEPENDENT STUDY SPACE.  

ERIC Educational Resources Information Center

BECAUSE OF THE DEMAND FOR INDIVIDUALIZED INSTRUCTION, NEW SCHOOLS ARE BEING PLANNED WITH LESS CLASSROOM SPACE AND MORE LIBRARY AND INDIVIDUAL STUDY SPACES. THESE NEW SCHOOLS REQUIRE NEW KINDS OF FURNITURE DESIGNED PRIMARILY TO GIVE THE STUDENT A DEGREE OF PRIVACY RATHER THAN TO PROVIDE OPTIMUM CONTROL TO TEACHERS. THE CARREL, PREVIOUSLY USED…

BEYNON, JOHN

193

Hanford Groundwater Scenario Studies.  

National Technical Information Service (NTIS)

This report documents the results of two Hanford groundwater scenario studies. The first study examines the hydrologic impact of increased groundwater recharge resulting from agricultural development in the Cold Creek Valley located west of the Hanford Re...

R. C. Arnett R. E. Gephart R. A. Deju C. R. Cole S. W. Ahlstrom

1977-01-01

194

Diabetic Retinopathy Study.  

National Technical Information Service (NTIS)

The Diabetic Retinopathy Study (DRS) was a multicenter clinical trial to evaluate the efficacy of photocoagulation, (argon laser and xenon arc) in the treatment of proliferative diabetic retinopathy. This randomized, controlled study involved 1,758 patien...

1981-01-01

195

Diabetic Retinopathy Study Data.  

National Technical Information Service (NTIS)

The Diabetic Retinopathy Study (DRS) was a multicenter clinical trail to evaluate the efficacy of photocoagulation, (argon laser and xenon arc) in the treatment of proliferative diabetic retinopathy. This randomized, controlled study involved 1,758 patien...

1983-01-01

196

National Cooperative Gallstone Study.  

National Technical Information Service (NTIS)

The study was divided into two phases: (1) the pre-clinical (Phase I) which included all organizational, protocol development, treatment center and service laboratory selections, and animal toxicology studies and (2) the clinical phase (Phase II). The cli...

1975-01-01

197

National Cooperative Gallstone Study.  

National Technical Information Service (NTIS)

The study was divided into two phases; (1) the pre-clinical (Phase I) which included all organizational, protocol development, treatment center and service laboratory selections, and animal toxicology studies and (2) the clinical phase (Phase II). The cli...

1977-01-01

198

National Cooperative Gallstone Study.  

National Technical Information Service (NTIS)

A comprehensive progress report of the National Cooperative Gallstone Study is provided. The Study was divided into two phases: (1) The pre-clinical (Phase I) which included all organizational, protocol development, treatment center and service laboratory...

1979-01-01

199

Population and Economic Study.  

National Technical Information Service (NTIS)

The Population and Economic Study is an analysis of past, present, and future trends in population and economic growth. The Study presents a brief discussion of the historical, geographic, and socio-economic characteristics of the area. The population sec...

1972-01-01

200

Psychiatry Practice Study Report.  

National Technical Information Service (NTIS)

The University of Southern California School of Medicine's Division of Research in Medical Education (USC/DRME) is conducting a nationwide study of practicing physicians in more than 20 medical and surgical specialties. The study's purpose is to provide a...

R. C. Mendenhall

1979-01-01

201

Wound Healing Studies.  

National Technical Information Service (NTIS)

Studies directed toward improving wound healing and resistance to wound infection of severely injured soldiers have been carried out aimed at establishing improved prophylactic and therapeutic measures. The studies are based on our view that some of the c...

S. M. Levenson

1981-01-01

202

Hematology Practice Study Report.  

National Technical Information Service (NTIS)

The University of Southern California School of Medicine's Division of Research in Medical Education (USC/DRME) is conducting a nationwide study of practicing physicians in more than 20 medical and surgical specialties. The study's purpose is to provide a...

R. C. Mendenhall

1979-01-01

203

Industrial Time Service Study.  

National Technical Information Service (NTIS)

The study examines options for delivery of accurate time and frequency information to industrial users. The study is sponsored by the Bonneville Power Administration (BPA) who finds a need for accurate timing to the one microsecond level. Prospective exis...

D. W. Hanson D. A. Howe

1986-01-01

204

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 ...

205

Case Study Teaching  

ERIC Educational Resources Information Center

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.)

Herreid, Clyde Freeman

2011-01-01

206

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.

207

Qualitative Case Study Guidelines.  

National Technical Information Service (NTIS)

This report presents guidelines for conducting qualitative case studies. Yin's case study process is elaborated on and additional principles from the wider literature are integrated and explained. It is expected that following the guidelines presented in ...

S. Baskarada

2013-01-01

208

PPP Effectiveness Study.  

National Technical Information Service (NTIS)

This design note presents a study of the Procedures and Performance Program (PPP) effectiveness. The intent of the study is to determine manpower time savings and the improvements in job performance gained through PPP automated techniques. The discussion ...

J. D. Arbet R. L. Benbow

1976-01-01

209

Cultural Environmental Studies  

NSDL National Science Digital Library

The American Studies Program of Washington State University offers this online directory to Websites and resources in cultural environmental studies. The directory presents a subject overview followed by a dozen or more subtopic headings which lead to annotated listings further broken down by subheadings. The site is frequently updated and provides a wealth of links for studying the last two centuries from a cultural studies viewpoint.

210

Case Study: Shark Attack  

NSDL National Science Digital Library

This is a case study for undergraduate students in anatomy or anatomy lab. In particular this case study explores the anatomy of the upper extremity. Users of the National Center for Case Study Teaching in Science will be required to register (free) to gain access to the answer key (and must be of teaching status to receive the key). Included in the resource are the case overview, objectives, case study, teaching notes and answer key.

Herbert House (Elon University Biology)

2002-05-24

211

Satellite servicing economic study  

NASA Technical Reports Server (NTRS)

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.

1990-01-01

212

Satellite servicing economic study  

NASA Technical Reports Server (NTRS)

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.

1990-01-01

213

Case Study: Uretero What?  

NSDL National Science Digital Library

This is a case study for high school, undergraduate and/or professional students in physiology and anatomy. In particular this case study explores reproductive biology. Users of the National Center for Case Study Teaching in Science will be required to register (free) to gain access to the answer key (and must be of teaching status to receive the key). Included in the resource are the case overview, objectives, case study, teaching notes and answer key.

Laura Lorentzen (Kean University Science and Technology Education)

2008-04-08

214

Case Study: Ellen's Choice  

NSDL National Science Digital Library

This is a case study for undergraduate students in anatomy and physiology. In particular this case study explores spinal anatomy, aging of bone, and explores the basic physiology of inflammation. Users of the National Center for Case Study Teaching in Science will be required to register (free) to gain access to the answer key (and must be of teaching status to receive the key). Included in the resource are the case overview, objectives, case study, teaching notes and answer key.

Elizabeth Harper (New York University Steinhardt School of Education Department of Health Studies)

2001-04-03

215

Case Study Research  

ERIC Educational Resources Information Center

Case study research aims to explore and depict a setting with a view to advancing understanding. This note explores the dimensions of case study research in higher education, with special reference to geographical fieldwork. It explores Stake's three categories of case study research: intrinsic, instrumental and collective. It provides guidelines…

Cousin, Glynis

2005-01-01

216

Hanford groundwater scenario studies  

Microsoft Academic Search

This report documents the results of two Hanford groundwater scenario studies. The first study examines the hydrologic impact of increased groundwater recharge resulting from agricultural development in the Cold Creek Valley located west of the Hanford Reservation. The second study involves recovering liquid radioactive waste which has leaked into the groundwater flow system from a hypothetical buried tank containing high-level

R. C. Arnett; R. E. Gephart; R. A. Deju; C. R. Cole; S. W. Ahlstrom

1977-01-01

217

NYU Women's Health Study  

Cancer.gov

For more than 25 years, the NYU Women’s Health Study has been committed to studying the potential causes of serious diseases in women in the United States. When the study began in 1985, its goal was to identify the role of hormones and diet in the development of the most common cancers in women, especially breast cancer.

218

Graduate Liberal Studies.  

ERIC Educational Resources Information Center

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

Brown, Peggy, Ed.

1982-01-01

219

Qualitative Studies: Historiographical Antecedents.  

ERIC Educational Resources Information Center

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…

Mills, Rilla Dean

220

Foreign Studies: Teacher's Guide.  

ERIC Educational Resources Information Center

Foreign Studies, an elective course for junior and senior students, is a study of selected Asian cultures, including the nations of China, Japan, and India, and of African cultures, including the nations of Nigeria, Ethiopia, and the Democratic Republic of the Congo. Asia and Africa are studied from the American cultural viewpoint with emphasis…

Hantula, James

221

Explanatory Observational Studies.  

ERIC Educational Resources Information Center

The state of the art in observational studies is discussed, with emphasis on explanatory research--studies of program effectiveness in which an attempt is made to explain the reasons for the results as well as describing the results. In addition to the collection of data and presentation of statistical facts, the explanatory study involves the…

Cooley, William W.

222

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

223

Social Psychoanalytic Disability Studies  

ERIC Educational Resources Information Center

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…

Goodley, Dan

2011-01-01

224

Defining (Conceptualizing) Social Studies.  

ERIC Educational Resources Information Center

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

Shaver, James P.

1990-01-01

225

Why Study Italian?  

ERIC Educational Resources Information Center

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

Haines, Charles

1978-01-01

226

Moving Force Identification Studies, II: Comparative Studies  

NASA Astrophysics Data System (ADS)

The theoretical background for four moving force identification methods has been presented in a companion paper. This part of the paper is an extension of the work to study the applicability of the four moving force identification methods. The parameters under study include the speed of vehicles, sampling frequency, axle-spacing-to-span ratio, and sensitivity towards noise. For the time domain method and frequency-time domain method, recommendation of the number of strain gauges is included. A comparison of the accuracy of the force identification using the four methods is given. Both illustrative and experimental results show that each method has its merits and limitations. It is found that the TDM gives the best results, but it is time consuming. Recommendations are given for each method to improve their performance and range of application. Further investigation would be to merge the four identification methods into a moving force identification system (MFIS).

CHAN, T. H. T.; YU, L.; LAW, S. S.; YUNG, T. H.

2001-10-01

227

Chemical studies for SYNTHOIL Processes heater studies  

Microsoft Academic Search

Non-catalytic liquefaction of West Virginia (Ireland Mine) coal in creosote oil was studied in a four stage, packed continuous reactor. Reactor conditions included 425°C, 4000 psi, liquid space velocities of 140 to 1600 lbs\\/h-ft³ and gas rates of 260 to 2800 MSCF\\/ton of coal to bracket conditions used in the SYNTHOIL preheater. Gas flow rates had no significant effect on

R. K. Traeger; R. M. Curlee

1978-01-01

228

Mars Aerocapture Systems Study  

NASA Technical Reports Server (NTRS)

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.

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

229

[Under study or treatment?].  

PubMed

Persons taking part in a clinical study are patients in the need of treatment. Although the values of the study and the treatment are largely consistent with each other, their goals, methods and ethics differ. Randomized studies in particular involve features that are strange to conventional treatments, such as blinding and placebo medication. Anyone participating in a study should understand that instead of obtaining a health benefit for an individual participant, its primary goal is generalizable knowledge. Any misunderstanding of the therapeutic meaning of the study may lead to disappointment of the participant. PMID:23786109

Keränen, Tapani; Pasternack, Amos

2013-01-01

230

Morphological Study of Lumbricals - A Cadaveric Study  

PubMed Central

The apparently simple human function of closing the hand to grasp an object or opening the palm to release it are in reality tasks of considerable mechanical complexity requiring the contraction of many individual muscles Lumbricals are important part of intrinsic musculature of hand. Though several deviations from normal have been described in standard textbooks of anatomy, a review of basic anatomy of lumbricals will be helpful. Aim: Proper knowledge about anatomy and variaitions prevalent in intrinsic musculature of hand is mandatory for various surgical procedure like cleft hand surgery, pollicization & other digital transposition procedures Present study was conducted to study morphology & variations prevalent in this region. The results were compiled and tried to find out commonest variations Phylogenetical & ontogenetical basis and clinical applications related to variations encountered were tried to know by correlating it with available literature. Material & Methods: For this study 50 hands of formalin embalmed cadavers were dissected The limbs were labelled R OR L for right or left, M or F for male or female. Cunnigham’s manual for dissection was followed for dissection. Results: Origin and nerve supply of lumbricals was normal in all hands. The variations were encountered in insertion of the 3rd lumbrical (32%) and 4th lumbrical (24%) were more confined to the right hand. Variations encountered commonly were split and misplaced insertion of third & fourth lumbricals. These variations are critically analyzed in the light of accessible literature. Conclusion: Lumbricals are more variable in the insertion rather than the origin & nerve supply. The variation commonly seen were split & misplaced insertion Split insertion was common in the third lumbrical whereas misplaced insertion is more common in the fourth lumbrical Variations are more common on right hands.

Parminder, Kaur

2013-01-01

231

Teleoperator human factors study  

NASA Technical Reports Server (NTRS)

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.

1986-01-01

232

The Stream Study  

NSDL National Science Digital Library

The Stream Study provides a method to determine the water quality of a stream based on the collection and identification of stream-bottom macroinvertebrates. This is a multi-chapter activity designed for teachers, parents, and students. Specific sections of this site include the following: why it is important to study stream-bottom macroinvertebrates, identification of stream-bottom macroinvertebrates, collection and interpretation of data, and a glossary of terms used in the stream study.

Webb, Rick

1999-03-01

233

Pathology Case Study: Hydrocephalus  

NSDL National Science Digital Library

The University of Pittsburgh School of Medicine's Department of Pathology has compiled a series of case studies to help both students and instructors. In this particular study an otherwise healthy 9 month old infant is presented with hydrocephalus. The case study provides test results and images along with microscopic photos and description. Clicking on the final diagnosis provides a thorough explanation of the diagnosis and treatment.

2007-08-20

234

Piloted rover technology study  

NASA Technical Reports Server (NTRS)

This is the May 25, 1990 summary report for Space Transfer Concepts and Analyses (STCA) Study, special study task 9.1, Piloted Rovers Technology Study. Piloted rover concepts, mission scenarios, and the requirements necessary for completion of these missions resulting in the establishment of a lunar base. These tasks were intended to lead to a logical conclusion concerning which piloted rovers technologies are needed to accomplish the various missions, along with a recommended schedule for the development of these technologies.

Thrasher, D. L.

1990-01-01

235

Scripture Study 101  

NSDL National Science Digital Library

In addition to learning HOW to study the sciptures, it\\'s important to understand WHY. OBJECTIVE The student will be able to name at least three reasons why we are to study the scriptures. The student will also be able to name three scripture study ideas. The student will demonstrate his mastery in the following three ways: (a) recording his findings in his class journal; (b) ...

Taylor, Jennie

2006-10-03

236

STRATNET: Strategic Studies Network  

NSDL National Science Digital Library

The University of Calgary's Strategic Studies Program developed STRATNET to provide a network of research resources germane to the study of international relations, security, and politics. STRATNET includes three main sections: StratChat, an interactive discussion forum; StratLink, a well-organized collection of hundreds of annotated strategic studies pointers; and StratJournal, which contains a multidisciplinary online journal entitled STRATNET. In addition, the site provides information about the fellows and the outreach projects of the Strategic Studies Program at the University of Calgary.

237

Case Study: Football Fanaticism  

NSDL National Science Digital Library

This is a case study for undergraduate and professional degree students in anatomy, physiology and/or pharmaceutical sciences. In particular this case study explores the anatomy of the central nervous system, major motor and sensory tracts. Integrative physiology courses may use this case to incorporate the immune, nervous and cardiovascular systems. Users of the National Center for Case Study Teaching in Science will be required to register (free) to gain access to the answer key (and must be of teaching status to receive the key). Included in the resource are the case overview, objectives, case study, teaching notes and answer key.

PhD Dayton J Ford (St. Louis College of Pharmacy Department of Pharmaceutical Sciences)

2003-07-03

238

Xenia Spacecraft Study  

NASA Technical Reports Server (NTRS)

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.

Hopkins, Randy

2009-01-01

239

Field Polymer Stability Studies  

Microsoft Academic Search

The highlights of the results obtained from a field test designed to study shear degradation of polyacrylamide polymers are presented. Recently, most major research laboratories have been studying shear degradation in the laboratory; however, no extensive field testing has been reported. The field test consisted of injecting Pusher 700 into a well at 4 different rates and back producing the

Bilhartz H. L; G. S. Charlson

1975-01-01

240

Dose Translation Study - 1964.  

National Technical Information Service (NTIS)

Based on the exposure data collected in a 1964 X-ray exposure study, the gonad dose and the genetically significant dose for the U.S. population have been estimated in the dose translation study. The application of several models was required in the proce...

J. Gitlin, N. Goldstein, J. Gaskill

1964-01-01

241

Cuban Studies Newsletter.  

ERIC Educational Resources Information Center

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…

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

242

Delaware Valley Impact Study.  

National Technical Information Service (NTIS)

The study is directed toward the evaluation of the impact of various projects proposed along the Delaware River, upon the transportation, economic and population growth of the region. The findings of the study are presented in four parts: the existing con...

1969-01-01

243

KET Social Studies Posters  

NSDL National Science Digital Library

The KET Social Studies posters provide an overview of the five “big ideas” that make up Kentucky’s K-12 social studies curriculum. These posters are appropriate for classroom display for both student and teacher reference. Each poster is available in two sizes and may be printed in color or black and white.

Ket

2012-02-15

244

Ethnic Studies in Pennsylvania.  

ERIC Educational Resources Information Center

To provide information to educators and curriculum developers on strengths, weaknesses, and needs of ethnic studies programs in Pennsylvania, the report offers an overview of the nature and extent of ethnic studies programs operated by Pennsylvania's postsecondary institutions, public school systems, and nonpublic schools. Information is based on…

Washburn, David E.

245

Morphological studies on neuroglia  

Microsoft Academic Search

The silver-impregnation procedure of Tsujiyama is suitable for demonstration of all three classical types of neuroglial cells; in the present study it was used for electron microscopic identification of neuroglial cells in the brain of the cat. The aim of the present study was 1) to determine impregnated structural correlates of neuroglial cells at the light- and electron-microscopic levels, and

Y. Murabe; Y. Sano

1981-01-01

246

Studying Management. Inaugural Lecture,  

National Technical Information Service (NTIS)

The purpose of the paper is to describe what the study of Management is, why Universities in general, and this one in particular, should pursue this study, and how the recent establishment of this subject on a proper basis at Cambridge University should b...

S. R. Watson

1987-01-01

247

Teaching Lesbian Studies  

Microsoft Academic Search

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

Esther D. Rothblum

2012-01-01

248

Naval Battle Casualty Study.  

National Technical Information Service (NTIS)

The study was carried out from January to June 1968 at the Naval Support Activity Station Hospital, DaNang, Republic of Vietnam. The purpose of the study was to document the injuries sustained, treatment given, and initial results of treatment occurring t...

J. G. Garrick

1973-01-01

249

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...

250

Extreme Scale Computing Studies.  

National Technical Information Service (NTIS)

This document is the draft Final Technical Report for Georgia Institute of Technology (Georgia Tech, GT) Project 210667V, 'Exascale Computing Study' (ECS). Four studies were conducted to determine the technical developments needed for a 1,000x increase in...

D. P. Campbell M. A. Richards

2010-01-01

251

Study Close-Out  

Cancer.gov

Step 4: Closing Out a Cancer Prevention Clinical Trial These documents are intended for the use of DCP Consorta staff conducting cancer chemoprevention studies under contract with NCI/DCP. SOP #2: Study Close-Out Responsibilities (SOP) (doc, 48kb) Lists

252

The safeguards options study  

Microsoft Academic Search

The Safeguards Options Study was initiated to aid the International Safeguards Division (ISD) of the DOE Office of Arms Control and Nonproliferation in developing its programs in enhanced international safeguards. The goal was to provide a technical basis for the ISD program in this area. The Safeguards Options Study has been a cooperative effort among ten organizations. These are Argonne

E. A. Hakkila; M. F. Mullen; C. T. Olinger; W. D. Stanbro; A. P. Olsen; C. T. Roche; R. R. Rudolph; A. M. Bieber; J. Lemley; E. Filby

1995-01-01

253

Advanced planetary studies  

NASA Technical Reports Server (NTRS)

Results of planetary advanced studies and planning support are summarized. The scope of analyses includes cost estimation research, planetary mission performance, penetrator mission concepts for airless planets/satellites, geology orbiter payload adaptability, lunar mission performance, and advanced planning activities. Study reports and related publications are included in a bibliography section.

1976-01-01

254

1990 NACUBO Endowment Study.  

ERIC Educational Resources Information Center

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,…

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

255

Measuring Maths Study Support  

ERIC Educational Resources Information Center

This article presents evidence that maths diagnostic assessments, consequent individualized learning programmes and face-to-face maths study support can combine to significantly increase maths related module pass rates and scores for undergraduate engineering students. It is argued that simply having a quiet, relaxed, supported study area,…

Patel, Chetna; Little, John

2006-01-01

256

Neurology Practice Study Report.  

National Technical Information Service (NTIS)

This is a report of a study on the practice of Neurology in the United States. The study, is intended to provide practice-relevant information to guide decision making in both educational program development and manpower planning. This report describes th...

R. C. Mendenhall

1979-01-01

257

Advanced Engine Study Program.  

National Technical Information Service (NTIS)

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 de...

A. I. Masters D. E. Galler T. F. Denman R. A. Shied J. R. Black

1993-01-01

258

Managerial Accounting. Study Guide.  

ERIC Educational Resources Information Center

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…

Plachta, Leonard E.

259

Digital Hydraulic Actuator Study.  

National Technical Information Service (NTIS)

The progress is reported on the Digital Hydraulic Actuator (DHA) Study as related to a Polaris application. The purpose of the DHA Phase I Study is to establish and define the pertinent parameters which impact control system performance with Polaris as a ...

1964-01-01

260

Age Discrimination Study.  

National Technical Information Service (NTIS)

An age discrimination study was initiated in July, 1976 in response to provisions of the Age Discrimination Act enacted by Congress in 1975. The act requires the U.S. Commission on Civil Rights to study unreasonable discrimination based on age in programs...

1977-01-01

261

Study Skills and Learning.  

ERIC Educational Resources Information Center

The series of research studies contained in this project emphasize the central position of the learning process in research into teaching. The main studies under the project were based on four sets of material collected in the course of three academic years. A number of supplementary collections and processings of other material were also…

Marton, Ference; Svensson, Lennart

1976-01-01

262

Energy conversion alternatives study  

NASA Technical Reports Server (NTRS)

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.

Shure, L. T.

1979-01-01

263

Qualitative Studies in HRD.  

ERIC Educational Resources Information Center

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

1999

264

Facilitating Teacher Study Groups  

ERIC Educational Resources Information Center

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…

Walpole, Sharon; Beauchat, Katherine A.

2008-01-01

265

Interagency Depainting Study Status  

NASA Technical Reports Server (NTRS)

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.

Clark-Ingram, Marceia; Cook, Beth

1999-01-01

266

Flood Insurance Study  

Microsoft Academic Search

This Flood Insurance Study investigates the existence and severity of flood hazards in the City of Layton, Davis County, Utah, and aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. This study will be used to convert Layton to the regular program of flood insurance by the Federal Emergency

1982-01-01

267

Computer Associative Memory Study.  

National Technical Information Service (NTIS)

Work done in the Computer Associative Memory Study Program is described. The object was to determine whether use of an Associative Memory would be of value in spaceborne computing problems. The results of the study are that a class of spaceborne problems ...

1964-01-01

268

Textbook Theme Studies.  

ERIC Educational Resources Information Center

Focuses on thematic units in elementary social studies, arguing that theme studies engage students, reduce boredom, and encourage cooperation, and more effectively use textbook information. Explores the selection process for choosing themes and subthemes. Illustrates two themes--festivals and buildings/houses--and suggests several activities…

Handley, Leslie Mills, Ed.

1989-01-01

269

Ontario Health Study (OHS)  

Cancer.gov

Launched in September 2010, the Ontario Health Study (OHS) is a prospective longitudinal cohort study. The OHS is an integrated platform for investigating the complex interplay of environmental, lifestyle and genetic components that increase individual and community risk of common adult diseases.

270

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...

271

The Monitoring Case Studies  

Microsoft Academic Search

The book so far has focused on the problems associated with habitat monitoring and ways of overcoming them: the remainder of the book primarily comprises case studies that demonstrate the practical application of monitoring. The case study sites are distributed in five countries: England, Finland, Germany, Sweden and Wales, though most originate from Wales (Fig.16-1) and Sweden. In selecting the

Clive Hurford; Michael Schneider

272

Teaching Social Studies Creatively.  

ERIC Educational Resources Information Center

Addresses the issue of creative teaching in social studies. Examines the way the creative classroom looks, how teachers can become more creative, and the importance of creative teaching in social studies. Concludes that creativity can foster students' understanding of social issues and aid in the retention of students until graduation. (RW)

Solomon, Warren

1989-01-01

273

SIAST Longitudinal Study.  

ERIC Educational Resources Information Center

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

Sarkar, Gerlinde

274

SETDA Case Studies 2012  

ERIC Educational Resources Information Center

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…

State Educational Technology Directors Association, 2012

2012-01-01

275

World Biofuels Study.  

National Technical Information Service (NTIS)

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 Inde...

T. Alfstad

2008-01-01

276

Laser ignition studies  

SciTech Connect

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.

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

1985-10-01

277

Teaching lesbian studies.  

PubMed

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

Rothblum, Esther D

2012-01-01

278

Women's Studies Librarian  

NSDL National Science Digital Library

The University of Wisconsin System Women's Studies Librarian offers a web page that provides exhaustive lists of bibliographies of monographs and scholarly articles in women's studies. The site also offers core lists of women's studies books in print on subjects from aging to women of color, compiled by the Association of College and Research Libraries Women's Studies Section. These core lists are intended to aid librarians in building women's collections, as well as guide teaching faculty in selecting course materials. Publishers and prices are provided. The page also points to selected women's Internet subject resources, e-zines and newsletters, and syllabi and course materials. http://www.library.wisc.edu/libraries/WomensStudies/

279

National Election Studies  

NSDL National Science Digital Library

In this season of electoral uncertainty, both researchers and concerned citizens can find the extensive data available at the National Election Studies Website quite useful. "NES conducts national surveys of the American electorate in presidential and midterm election years and carries out research and development work through pilot studies in odd-numbered years. The NES time-series now encompasses 23 biennial election studies spanning five decades." The data from these studies, along with codebooks, cover public opinion and political participation themes such as "expectations about the election outcome; perceptions and evaluations of the major parties and their candidates; interest in the campaign; information about politics; partisanship; assessments of the relative importance of major problems facing the country; attention to campaign coverage in the mass media; feelings of political efficacy; political values; conservatism vs. liberalism; trust in government; political participation; vote choice; economic well-being; positions on social welfare, economic, social, and civil rights issues" and more. Pilot studies, whose data is also available on-site, are conducted in off-election years in order "to test new, or refine existing, instrumentation and study designs." A major feature of the site, useful to not only researchers but journalists and the general public, is The NES Guide to Public Opinion and Electoral Behavior, which offers easily digestible data on a whole range of issues drawn from the time-series studies.

280

Outer planet studies  

NASA Technical Reports Server (NTRS)

Spectrophotometric observation were completed of Titan and determinations of its geometric and Bond albedos and completion of like observations of Uranus, pre-Voyager encounter. CH3D was studied in the spectrum of Uranus and a determination of the CH3D/CH4 mixing ratio in its atmosphere. The observations needed for a direct calibration of the Sun against Vega was completed. The study was continued of CH3D in the spectra of Saturn and Titan. High resolution observations of O I, C2 and C-12 C-13 in the coma of P/Halley were also studied.

Lutz, B. L.; Lockwood, G. W.

1986-01-01

281

Studying aging in Drosophila.  

PubMed

Drosophila melanogaster represents one of the most important genetically accessible model organisms for aging research. Studies in flies have identified single gene mutations that influence lifespan and have characterized endocrine signaling interactions that control homeostasis systemically. Recent studies have focused on the effects of aging on specific tissues and physiological processes, providing a comprehensive picture of age-related tissue dysfunction and the loss of systemic homeostasis. Here we review methodological aspects of this work and highlight technical considerations when using Drosophila to study aging and age-related diseases. PMID:24751824

He, Ying; Jasper, Heinrich

2014-06-15

282

Tokamak reactor studies  

SciTech Connect

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.

Baker, C.C.

1981-01-01

283

F-14 modeling study  

NASA Technical Reports Server (NTRS)

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.

Levison, William H.

1988-01-01

284

IUPAP Report: Benchmarking Study  

NASA Astrophysics Data System (ADS)

This paper reports on an international study that was conducted on the participation of women in physics. Rachel Ivie and Katie Stowe of the Statistical Research Center carried out this study during 2001. Approximately 900 women physicists from over 50 countries provided information about their educational and employment histories. These personal narratives were analyzed in the context of the educational systems of the countries in which the women physicists studied and the economic structure of the countries within which they worked. This paper will also address critical events and environment features that facilitate the participation of women and those that are barriers to their success.

Czujko, Roman

2002-03-01

285

Materials Failure Case Studies  

NSDL National Science Digital Library

This website offers innovative course materials for teaching engineering design and analysis through failure case studies, supporting the integration of research in forensic engineering into undergraduate education. The site includes an introduction to the overall project and a bibliography as well as typical civil engineering and engineering mechanics courses, with over 50 case studies currently listed. This web site is a companion to the book Beyond Failure: Forensic Case Studies for Civil Engineers, Delatte, Norbert J., ASCE Press. The site is a living document that will supplement the book with web links, additional information, and supplemental illustrations. At this time, not all of the cases have been filled in yet.

Delatte, Norbert J., Jr.

2008-12-12

286

Online Study Guides  

NSDL National Science Digital Library

This site features study guides prepared by English Professor Paul Brians of Washington State University for his classes, but available free of charge to Web users, provided they credit the author. The site offers study guides to an extensive library of works, including texts in the fields of science fiction, world history, eighteenth and nineteenth century European classics, Renaissance and World Literature, and the Bible. The study guides not only provide detailed summaries and analyses of the texts, but helpful glossaries of vocabulary and allusions, related Web links, and explanations of key cultural concepts. All together, there are study guides for about 75 texts as well as useful guides to such things as Misconceptions, Confusions, and Conflicts Concerning Socialism, Communism, and Capitalism; and French Impressionist painting.

Brians, Paul.

287

Irrigation Systems Study.  

National Technical Information Service (NTIS)

This study was undertaken to upgrade and improve existing and future highway landscaping irrigation methods and procedures. The selection, installation, and use of materials and equipment are covered in relation to design, construction, and maintenance. E...

R. F. Reiland F. Salvisberg W. F. Crozier R. A. Pelkey

1980-01-01

288

Battered Women Syndrome Study.  

National Technical Information Service (NTIS)

Identification and assistance in understanding battered women were studied. Among the conclusions were that women behaved in ways that were reactive to battering. Battered women come from all social classes, they held attitudes toward women's roles that w...

L. E. Walker

1983-01-01

289

Milwaukee Study Area.  

National Technical Information Service (NTIS)

This report is part of an overall research study being conducted by the American Society of Civil Engineers (ASCE) to determine the feasibility of separating combined sewerage by using a system of pressure conduits to convey sanitary sewage from individua...

1968-01-01

290

Studying Eco Climatic Domains  

NSDL National Science Digital Library

Activity is a Project BudBurst/National Ecological Observatory Network (NEON) exploration of eco-climactic domains, as defined by NEON, by investigating characteristics of a specific domain and studying two representative plants in that domain.

Neon; Budburst, Project

291

Soil-Cement Study.  

National Technical Information Service (NTIS)

This study consisted of an examination of the compressive strengths of soil-cement mixtures on 15 construction projects from the standpoint of design and actual achievement. The laboratory design test was examined closely along with the present field meth...

J. L. Melancon S. C. Shah

1973-01-01

292

Propylene Glycol Antifreeze Study.  

National Technical Information Service (NTIS)

The use of propylene glycol (PG) base antifreeze in military vehicles is examined. Two approaches of adopting PG antifreeze into military maintenance practices are studied. The approaches include the use of a design specification and the use of a performa...

D. Davis

1996-01-01

293

Operator Certification Study Guide.  

ERIC Educational Resources Information Center

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)

American Water Works Association, Denver, CO.

294

Tethered gravity laboratories study  

NASA Technical Reports Server (NTRS)

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

Lucchetti, F.

1989-01-01

295

Long Term Care Study.  

National Technical Information Service (NTIS)

Long-term care needs and facilities in Saginaw, Mich., and alternatives to institutionalization were investigated. The instrument for the study was designed by the East Central Michigan Health Systems Agency. Long-term care facilities in Saginaw were surv...

1978-01-01

296

Studies in Chemical Dynamics.  

National Technical Information Service (NTIS)

Progress made in the following studies is reported: low-energy electron scattering; variable-angle photoelectron spectroscopy; laser photochemistry and spectroscopy; and collisions in crossed molecular beams. (ERA citation 04:034377)

A. Kuppermann

1978-01-01

297

Tonto Creek: Backwater Study.  

National Technical Information Service (NTIS)

The Bureau of Reclamation studied backwater and sediment deposition effects at Tonto Creek resulting from the recent modifications to Theodore Roosevelt Dam. The top of active conservation pool at Theodore Roosevelt Reservoir will be raised from 2,136 fee...

L. Lest

1997-01-01

298

Comparative Packaging Study  

NASA Technical Reports Server (NTRS)

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.

Perchonok, Michele; Antonini, David

2008-01-01

299

TNT Purification Studies.  

National Technical Information Service (NTIS)

This report describes laboratory studies of the purification of crude 2,4,6-trinitrotoluene (TNT) using ammonium sulfite and magnesium sulfite hexahydrate. The magnesium sulfite hexahydrate purification process produces acceptable TNT, but the TNT produce...

E. E. Gilbert J. R. Spencer R. A. Mundy

1981-01-01

300

LIMB PROCESS DEVELOPMENT STUDIES  

EPA Science Inventory

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

301

Advanced planetary studies  

NASA Technical Reports Server (NTRS)

Study concepts and planning analyses programs for NASA's solar system exploration are summarized. Data cover manpower/cost estimation research, Jupiter orbiter lifetime analysis, error/control analysis of penetrator deployment at the moon and Mercury, and advanced planning activities.

1975-01-01

302

Applied Research Study  

NASA Technical Reports Server (NTRS)

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.

Leach, Ronald J.

1997-01-01

303

Agricultural Health Study  

Cancer.gov

A fact sheet about the Agricultural Heath Study, begun In 1993 by scientists from the National Cancer Institute, the National Institute of Environmental Health Sciences, and the U.S. Environmental Protection Agency.

304

Current Research Studies  

MedlinePLUS

... disease and itslifelong consequences. Learn more about the Pediatric Risk Stratification Initiative. CCFA Partners CCFA Partners is a comprehensive Internet-based registry designed to study thousands of patients with Crohn's disease or ulcerative colitis under a ...

305

Management Tools Case Study.  

National Technical Information Service (NTIS)

This study investigated documentation and procedures for the NASA Integrated Programs for Aerospace Vehicle Design (IPAD) Program. The purpose was to assess IPAD's value to a proposed R&D program for evaluating the application of management principles and...

J. R. Brown L. S. Hammond

1979-01-01

306

SYSTEM STUDIES FOR ITER  

SciTech Connect

The following system studies were performed for the International Thermonuclear Experimental Reactor (ITER) using the Tokamak Engineering Test Reactor Analysis (TETRA) systems code: (1) a study of inductive vs current drive options for ITER, which addresses the cost trade-off of providing increased plasma burn capability inductively by increasing the bore of the ohmic heating (OH) solenoid (resulting in a tokamak with a larger major radius) as opposed to providing plasma current drive via rf or neutral beam injection (NBI); (2) an inboard shield trade study, which addresses the tradeoff of using tungsten or stainless steel shielding; and (3) a study of the impact of Confinement scaling on ITER parameters, which addresses the sensitivity of various proposed energy confinement time scaling algorithms on ITER ignition margin and cost.

Reid, R. L. [Oak Ridge National Laboratory (ORNL); Peng, Yueng Kay Martin [ORNL; Galambos, John D [ORNL

1989-01-01

307

Cancers Selected for Study  

Cancer.gov

The Cancer Genome Atlas researchers are mapping the genetic changes in 20 cancers. Find out which cancers have been selected for study, the criteria for selection and the scientific questions being asked about each cancer.

308

Genetic Services Benefit Study.  

National Technical Information Service (NTIS)

The report presents the final results of the Genetic Services Demonstration--an information-gathering project that assisted Blue Cross and Blue Shield Plans interested in expanding their coverage of genetic services. The categories of data studied were co...

J. O. Gibbs C. Henes G. N. Kaplan

1987-01-01

309

Aircraft Avionics Tradeoff Study.  

National Technical Information Service (NTIS)

The results of studies into digital system architectures, applicable to next-generation avionics systems, are presented in this report. Representative requirements are developed for a lightweight fighter and a close air support system, both assumed to be ...

R. N. Furtaw D. T. Edson R. P. Teutsch J. S. Steiner

1973-01-01

310

Friction Pile Resistance Study.  

National Technical Information Service (NTIS)

This 1976 research study presents a rational application of empirical methods of estimating the driving resistance of prestressed concrete, steel and timber piling into the recent alluvial soils of Oregon, through the use of the Standard Split-Tube Sample...

J. L. Davis

1976-01-01

311

Wire Object Detection Study.  

National Technical Information Service (NTIS)

An analytic study and an experimental feasibility demonstration of the detection of wire objects has been completed. The techniques employed were based upon the geometric compatibility of the object to be detected and the sensor used, which in this instan...

R. Kleehammer

1978-01-01

312

Exploratory studies, 1988  

SciTech Connect

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.

Not Available

1989-05-01

313

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

314

Imaging Studies of Galaxies  

NASA Technical Reports Server (NTRS)

This talk will discuss the impact of imaging x-ray astronomy in our under- standing of galaxy properties. It will review the principal results of this type of studies and will address some recent Chandra results.

Fabbiano, Giuseppina

2000-01-01

315

Rotorcraft convertible engine study  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

316

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...

317

Gastroenterology Practice Study Report.  

National Technical Information Service (NTIS)

Descriptive and statistical analyses of the characteristics of gastroenterologists' practices in the United States are provided by this University of Southern California medical research study. Data reveal an overrepresentation of gastroenterologists in l...

1977-01-01

318

Teleportation Physics Study.  

National Technical Information Service (NTIS)

This study was tasked with the purpose of collecting information describing the teleportation of material objects, providing a description of teleportation as it occurs in physics, its theoretical and experimental status, and a projection of potential app...

E. W. Davis

2004-01-01

319

Accelerator research studies  

SciTech Connect

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.

Not Available

1992-01-01

320

Multiple Target Tracking Study.  

National Technical Information Service (NTIS)

A particular multiple target tracking mission was studied to determine the radar requirements. Several phased array radar configurations are described. A limited scan array is selected as the most cost effective. The phased array radar is compared with a ...

E. M. Brown D. N. Thomson

1974-01-01

321

Self Study Guide: Russia.  

National Technical Information Service (NTIS)

Self -Study Guide Russia is intended to provide U.S. government personnel in the foreign affairs community with an overview of important Russian issues related to history, culture, politics, economics, security and international relations. This guide shou...

2000-01-01

322

Vietnam: Self Study Guide.  

National Technical Information Service (NTIS)

The Self-Study Guide Vietnam is intended to provide U.S. government personnel in the foreign affairs community with an overview of important issues related to history, geography, politics, religion, culture, economics, and international relations. The gui...

2006-01-01

323

Civil Law Study Guide.  

National Technical Information Service (NTIS)

This study guide is intended to be a convenient reference for use by Navy and Marine Corps personnel on civil law subjects. Those subjects include, inter alia, JAG Manual investigations, enlisted administrative separations, officer personnel matters, rela...

1987-01-01

324

ADVANCED CUTTINGS TRANSPORT STUDY  

SciTech Connect

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.

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

325

Connecticut River Shad Study.  

National Technical Information Service (NTIS)

During the three years of the study period, the number of American shad (Alosa sapidissima) entering the Connecticut River was estimated. The Petersen Method was employed for this population estimate. The estimate for 1976 was greater than those during al...

P. Minta

1977-01-01

326

NCCCP: Comparative Case Studies  

Cancer.gov

For the case studies, RTI will conduct site visits during each of the three years of program implementation to obtain in-depth information about aspects of each program's design, development, and implementation.

327

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. ...

328

Habitability study shuttle orbiter  

NASA Technical Reports Server (NTRS)

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.

1972-01-01

329

IRD dropout study  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

330

Aquaculture Feasibility Study.  

National Technical Information Service (NTIS)

The Klamath Tribes contracted a study to determine the feasibility of tribal members establishing aquaculture ventures in Klamath County, Oregon. An evaluation of five privately owned sites showed three as having potential for Aquaculture. Potential speci...

1995-01-01

331

Community Child Health Studies.  

National Technical Information Service (NTIS)

The present research has sought to describe and analyze the overlapping health and educational services utilization pattern of children with disabilities and their families in a defined geographic area: Berkshire County, Massachusetts. The study tried to ...

D. K. Walker S. L. Gortmaker

1983-01-01

332

Fresnel Lens Study.  

National Technical Information Service (NTIS)

Thick film sol-gel technology was evaluated to determine the feasibility of utilizing sol-gels to produce embossable materials ultimately for the production of all-glass Fresnel optics. The feasibility study has utilized the relatively undeveloped branch ...

1986-01-01

333

Jordan: Self Study Guide.  

National Technical Information Service (NTIS)

The Self-Study Guide: Jordan is intended to provide U.S. Government personnel in the foreign affairs community with an overview of important issues related to Jordanian history, geography, politics, economics, culture, religion, media, and international r...

2002-01-01

334

Studies of Perceptual Memory.  

National Technical Information Service (NTIS)

Perceptual memory refers to experience-induced changes in perceptual processing of particular objects or scenes. Part 1 of this report summarizes the results of 8 studies of the role of perceptual memory in recognition memory. The hypothesis was confirmed...

J. M. Farnham K. J. Hawley W. A. Johnston

1992-01-01

335

Mass Memory Organization Study.  

National Technical Information Service (NTIS)

The purpose of this study is to develop a recommended organization for gigabit storage device having speed/bandwidth capabilities compatible with an associating type computer processor. Data acquired under this effort is based on the use of nonvolatile MN...

D. L. Farnsworth C. P. Hoffman J. J. Shutt

1976-01-01

336

Aquaculture Siting Study.  

National Technical Information Service (NTIS)

The Aquaculture Siting Study documents the analysis of potential visual and cumulative impacts from proposed aquaculture facilities. The intent is to provide an environmental assessment tool for use in evaluating and regulating these facilities.

1986-01-01

337

Electrical Propulsion Machinery Study.  

National Technical Information Service (NTIS)

The report covers the design analysis of electrical propulsion machinery suitable for naval propulsion applications. The primary objectives of this study were to identify the technical problem areas in the machines analyzed, and to develop methods of solv...

C. J. Mole

1973-01-01

338

IND Case Studies  

Cancer.gov

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES NATIONAL INSTITUTES OF HEALTH Working with FDA: Biological Products and Clinical Development IND Case Studies Karen D. Jones Chief, Project Management Staff Division of Biologic Oncology Products Office of

339

Earth study from space  

NASA Technical Reports Server (NTRS)

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.

Sidorenko, A. V.

1981-01-01

340

Wilson Cycle studies  

NASA Technical Reports Server (NTRS)

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.

Burke, Kevin

1987-01-01

341

LAKE NUTRIENT MODELING STUDY  

EPA Science Inventory

Determining the effects of morphological conditions, turbidity and watershed land use / land cover patterns on nutrient levels in Central Plains lakes and reservoirs. The study involves intensive field monitoring for the calibration and verification of basin and watershed models...

342

Power subsystem automation study  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

343

Tethered subsatellite study  

NASA Technical Reports Server (NTRS)

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.

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

344

Mysore childhood obesity study  

Microsoft Academic Search

We conducted this study to document the prevalence of obesity, overweight and underweight in the school children aged 5 to\\u000a 16 years from Mysore. 5 Principal Investigators and 13 Co-Investigators trained the teachers of 139 schools (Private-111,\\u000a Govt-28) to record the vital statistics of the children studying in their schools. A total of 43152 school children (23527\\u000a boys and 19625

M. Premanath; H. Basavanagowdappa; M. A. Shekar; S. B. Vikram; D. Narayanappa

2010-01-01

345

Banner Ad Placement Study  

NSDL National Science Digital Library

Webreference.com (discussed in the April 19, 1996 Scout Report) has recently added this interesting and thought-provoking resource to its site. The resource presents the results of a study of banner ad placement at webreference.com, conducted between March 25 and April 15, 1997 by three University of Michigan School of Business Administration students. The study concludes that changes in placement of banner ads affects "click-through" rates.

Doyle, Kim.; Minor, Anastasia.; Weyrich, Carolyn.

1997-01-01

346

IGCC system studies  

SciTech Connect

Systems studies are performed on both the currently available, but not fully demonstrated, integrated gasification combined-cycle (IGCC) technologies and the future technologies. The objective of these studies is to support and guide the Morgantown Energy Technology Center`s METC Strategic Product Planning efforts. Through these efforts, the research, development and demonstration needs of various alternative gasification and power island components can be quantified and factored into the overall planning processes.

Rath, L.K.

1994-10-01

347

Concrete containment aging study  

SciTech Connect

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).

Pachner, J. [International Atomic Energy Agency, Vienna (Austria); Tai, T.M. [Bechtel National, Inc., Oak Ridge, TN (United States); Naus, D. [Oak Ridge National Lab., TN (United States)

1994-04-01

348

NASA Propagation Studies Website  

NASA Technical Reports Server (NTRS)

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.

Angkasa, Krisjani S.

1996-01-01

349

PFBC system studies  

SciTech Connect

System studies of PFBC systems are summarized in this paper. These studies include: thermal efficiency; NO{sub x} stochastic analysis; dynamic modeling; scoping studies; and hazardous air pollutant (HAP) studies. These studies are being used for various reasons: to validate the economic and environmental benefits that this technology offers the country, to identify issues associated with the commercialization of PFBC technology, and to help the DOE and its industrial partners focus on those RD&D activities which produce the biggest bang for the buck, an increasingly important goal in the present climate of increasingly tight Federal and corporate budgets. This year, the conclusion that NO{sub x} generation in the solids combustor is the most important factor in determining NO{sub x} production in an uncontrolled system was of particular significance. The initial assessment of HAP`s, showing a possible reduction in HAPs emissions if the barrier filter is operated below 600 C in a first-generation PFBC, was the first time this type of data was produced on the ability of PFBC systems to be a low HAP`s emission technology. Work will continue to improve these analytic tools used in these system studies useful for both DOE and its industrial partners.

Reed, M.E.

1994-10-01

350

Wilson Cycle studies  

NASA Technical Reports Server (NTRS)

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.

Burke, Kevin

1987-01-01

351

ADVANCED CUTTINGS TRANSPORT STUDY  

SciTech Connect

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.

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

352

Rugby headgear study.  

PubMed

A two year randomised controlled trial of headgear in Rugby Union football is being conducted in Sydney, Australia. This paper gives an overview of this study in progress and presents results related to the development and laboratory performance of the headgear. The study commenced in 2002. Participants recruited to the study are in the under 13, 15, school open (U18) and colts age groups. There are three study arms: control, IRB-approved headgear, and modified headgear. The IRB approved headgear is a popular model in rugby, the Canterbury Honeycomb model manufactured by BodyArmour in New Zealand. The dimensions of this model were altered by increasing foam density and thickness to produce the modified headgear. In impact energy attenuation tests of 15 and 20 Joules onto a flat anvil, the modified headgear demonstrated average maximum headform accelerations of 23% and 33% of the standard model, respectively. Whether or not this improvement translates into reductions in injury will be determined by a comparison of the rates and severities of head injuries across study arms. Furthermore, these dimensional changes may not be acceptable to rugby players. Player attitudes towards safety and the use of protective clothing, injury history, experience and on-field behaviour will be examined via structured pre- and end of season surveys and analysis of match video. PMID:14609153

McIntosh, A S; McCrory, P; Finch, C F; Chalmers, D J; Best, J P

2003-09-01

353

Partial gravity habitat study  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

354

Cosmos-1989 immunology studies  

NASA Technical Reports Server (NTRS)

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.

Sonnenfeld, Gerald

1991-01-01

355

Black Hills hydrology study  

USGS Publications Warehouse

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.

Driscoll, D. G.

1994-01-01

356

REP Concept Feasibility Study  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

357

Ventilation technologies scoping study  

SciTech Connect

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).

Walker, Iain S.; Sherman, Max H.

2003-09-30

358

Wright Field turboprop study  

SciTech Connect

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.

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

1981-01-01

359

Cosmos: 1989 immunology studies  

NASA Technical Reports Server (NTRS)

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.

Sonnenfeld, Gerald

1991-01-01

360

Pathology Case Study: Sepsis  

NSDL National Science Digital Library

This is a case study presented by the University of Pittsburgh Department of Pathology where a 74 year old man with a history of diabetes mellitus, coronary artery disease, inferior wall myocardial infarction, peripheral vascular disease, hypertension, and hypercholesterolemia. He was admitted for a left femoral-popliteal bypass graft. The case study provides both gross and microscopic descriptions along with pertinent laboratory studies in order to allow the user the opportunity to diagnose the patient. Clicking on the final diagnosis link will provide users with a discussion of the actual diagnosis along with important learning points as well as a list of references. This is an excellent resource for students in health sciences to familiarize themselves with using patient history and laboratory results to develop a diagnosis. It is also a helpful site for educators to use to introduce or test student learning in pathology and clinical microbiology.

Callahan, Debra L.

2009-10-08

361

Seal design alternatives study  

SciTech Connect

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.

Van Sambeek, L.L. [RE/SPEC Inc., Rapid City, SD (US); Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D. [Parsons Brinckerhoff Quade & Douglas, Inc., San Francisco, CA (US)

1993-06-01

362

Iron studies in hemophilia  

SciTech Connect

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.

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

1981-12-01

363

Radiochemistry in RIB Studies  

SciTech Connect

Radiochemistry can be an important tool in studies of nuclear reactions induced by radioactive ion beams (RIBs). RIB intensities are typically 10{sup 3}-10{sup 5} particles/s leading to very low reaction rates. The sensitivity of radiochemical methods and the ability to uniquely determine the atomic properties of the reaction products offer substantial advantages. The application of radiochemical techniques to study the fusion of {sup 9,11}Li with {sup 70}Zn and the 'inverse fission' of uranium is described.

Loveland, Walter [Oregon State University; Shapira, Dan [ORNL

2008-09-01

364

Hybrid receiver study  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

365

Pathology Case Study: Dysphagia  

NSDL National Science Digital Library

The University of Pittsburgh School of Medicine's Department of Pathology has compiled a series of case studies to help both students and instructors. The patient in this particular case is a 64-year-old male with difficulty swallowing anything other than liquids. Patient history and both the gross and microscopic descriptions, which include images, are included in this case study. The contributing doctors provide a detailed discussion of the patientâÂÂs condition in the âÂÂFinal Diagnosisâ section. Students will find this resource especially helpful, as it provides experience with patient history, lab results, and diagnostics.

Barnes, Leon, 1941-; Fusco, Gregory P.; Perez, Mia C.

2009-08-25

366

Photothermal degradation studies  

NASA Technical Reports Server (NTRS)

Key reaction intermediates of photooxidation identified and characterized by laser flash Electron Spin Resonance (ESR) spectroscopy were discussed. Effects of temperature and ultraviolet intensity were studied in order to develop meaningful accelerated testing procedures for encapsulant evaluation. In a program to study the failure of Tedlar/ethylene vinyl acetate (EVA)/stainless steel modules, failure modes similar to those observed outdoors in real-time conditions were simulated in accelerated testing. An experimental technique was developed to quantitatively assess the extent of degradation.

Liang, R. H.

1985-01-01

367

Center for Nonlinear Studies  

NSDL National Science Digital Library

The Los Alamos National Laboratory provides the Center for Nonlinear Studies (CNLS) Website. The goals of the center are "to identify and study fundamental nonlinear phenomena and promote their use in applied research and to stimulate interdisciplinary research and information exchanges inside and outside the laboratory." Research topics include molecular dynamics, patterns in turbulence, stochastic dynamics, combinatorial optimization, and condensed matter, among others. Those interested in supercomputing will want to visit the section dedicated to Avalon, the CNLS supercomputer that is being used for applications ranging from astrophysics to molecular dynamics. Also at the Website, users may access information pertaining to jobs, meetings, talks, and papers.

Center for Nonlinear Studies (Los Alamos National Laboratory).

2005-10-31

368

Center for Nonlinear Studies  

NSDL National Science Digital Library

The Los Alamos National Laboratory provides the Center for Nonlinear Studies (CNLS) Website. The goals of the center are "to identify and study fundamental nonlinear phenomena and promote their use in applied research and to stimulate interdisciplinary research and information exchanges inside and outside the laboratory." Research topics include molecular dynamics, patterns in turbulence, stochastic dynamics, combinatorial optimization, and condensed matter, among others. Those interested in supercomputing will want to visit the section dedicated to Avalon, the CNLS supercomputer that is being used for applications ranging from astrophysics to molecular dynamics. Also at the Website, users may access information pertaining to jobs, meetings, talks, and papers.

Center for Nonlinear Studies (Los Alamos National Laboratory).

1999-01-01

369

Breakthrough Generations Study  

Cancer.gov

The Breakthrough Generations Study is a long-term cohort study of more than 110,000 women aged 16 years and older from the general population of the United Kingdom. Detailed questionnaire information is gathered at recruitment about factors that might relate to breast cancer risk or protection. Blood samples have been collected from more than 90 percent of cohort members. Follow-up rounds are designed to occur every 2½ years, with the intention to continue to collect data for the next 40 years or longer.

370

National Facilities study  

NASA Technical Reports Server (NTRS)

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.

1994-01-01

371

Studies in neuroendocrine pharmacology  

NASA Technical Reports Server (NTRS)

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.

Maickel, R. P.

1976-01-01

372

Cryogenic Propellant Densification Study  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

373

DWPF Welder Parametric Study  

SciTech Connect

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.

Plodinec, M.J.

1998-11-20

374

Study of electroweak interactions  

NASA Astrophysics Data System (ADS)

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.

Abashian, A.

375

Science Curriculum Topic Study  

NSDL National Science Digital Library

Need help making the connection between science standards, teacher practice, and improved student achievement? Science Curriculum Topic Study is your missing link. The book offers a systematic professional development strategy that brings together science standards and research with curriculum, instruction, and assessment. Writing in the book's foreword, Harold Pratt, former NSTA President, calls Science Curriculum Topic Study "by far the best thing I have seen on how to effectively use the standards." The CTS process will help you: � Improve your understanding of science content � Clarify a hierarchy of content and skills in a learning goal from state or local standards � Define formative and summative assessment goals and strategies � Learn to recognize and address learning difficulties � Design or use instructional materials effectively � Increase opportunities for students of all backgrounds to achieve science literacy Science Curriculum Topic Study is rich with features that make it both easy to use and illuminating. It contains 147 separate curriculum topic study guides arranged in 11 categories representing the major domains of science. You get worksheets to help you apply the CTS process to curriculum, instruction, and assessment, plus a quick-reference guide to the major standards and research documents. In addition, teacher vignettes show how to use the CTS process to enrich your own teaching immediately.

Keeley, Page

2005-01-01

376

Area Studies: China.  

ERIC Educational Resources Information Center

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

Blouin, Virginia; And Others

377

Graduate Time Study. 1992.  

ERIC Educational Resources Information Center

To determine the average time students take to complete an associate degree, certificate, or diploma, Harrisburg Area Community College (HACC), in Pennsylvania, conducted a study of all 944 students who graduated during the 1991-92 academic year. Data for the sample were gathered related to age, sex, grade point average, academic major, attendance…

Harrisburg Area Community Coll., PA. Office of Institutional Research.

378

An Ethnic Studies Library.  

ERIC Educational Resources Information Center

This annotated bibliography of ethnic studies materials is intended to be used in conjunction with a teacher education program. The collection of selected materials is designed to help elementary, secondary, and college teachers gain a greater understanding of the ethnic experience in the United States. Some of the items may also be used with…

Travalini, Paul, Comp.; Stavros, Gwen

379

Broadcast Regulation Tradeoff Study.  

National Technical Information Service (NTIS)

The primary objective of the study was to evaluate the overall and relative cost-effectiveness of five generic broadcast regulatory activities carried out by the FCC. The five areas are: (1) field enforcement; (2) station and operator licensing; (3) equip...

R. W. Rice E. E. Donaldson F. E. Gramling H. H. Jenkins D. L. Kelly

1979-01-01

380

Eiscat Electron Density Studies.  

National Technical Information Service (NTIS)

Studies of the auroral ionosphere by incoherent-scatter radar have continued, with further observations of the fine structure of the F-region and with detailed analyses of data so obtained during the last three years. It has been demonstrated that irregul...

J. K. Hargreaves C. J. Burns

1985-01-01

381

Plant Study Guide.  

ERIC Educational Resources Information Center

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…

Brynildson, Inga

382

Haemogenetic studies in Bulgaria.  

PubMed

Within a study of the genetics of Bulgarian populations, the markers AB0, RH, MNS, P, HPA, GM(1), PGM1, ACP and ESD were examined in 2346 individuals from seven subpopulations of south-central and south-eastern Bulgaria. The combined data have been compared with other populations of the Balkans. PMID:15962566

Baltova, S; Scheil, H G; Schmidt, H D

2005-06-01

383

Comparative study of \\  

Microsoft Academic Search

The paper compares the findings coming from three case studies for the case of mobile data services and highlights factors that could explain the low usage rates among the users. The movement of applications from desktop platforms to wireless and mobile configurations may have a significant impact on future daily activities. Mobile computing supported by broadband wireless networks allows users

Homer Papadopoulos

2008-01-01

384

Developmental Studies: Whose Responsibility?  

ERIC Educational Resources Information Center

A national study on Adult Functional Competency, conducted by the University of Texas, determined that less than one-half of the adult population (46%) was proficient in handling the demands of modern living. Educators have never done even an adequate job of educating the country's people. If the primary goal of the teaching profession is to…

Herd, Ruby H.

385

Harpoon pyrotechnic shock study  

Microsoft Academic Search

A study was conducted to compare predicted Harpoon missile pyrotechnic shock response with Harpoon missile design criteria. This report discusses the pyrotechnic shock environment and component failures encountered in this type of environment. Correct shock test simulation techniques and 'state-of-the-art' limitations are delineated. Actual testing techniques and test apparatus that can be used to achieve the proper test environment are

D. Powers; C. E. Wright; W. N. Jones

1979-01-01

386

Hypersonic Monorail Environmental Studies.  

National Technical Information Service (NTIS)

The results of a one year study program to define slipper loads and slipper gap air pressures on monorail test vehicles are presented and discussed. Two test vehicles, the Instrumented Monorail and the Slipper Test Device, were instrumented to measure the...

R. L. Abelt J. D. Richards

1968-01-01

387

Wood pellet feasibility study  

Microsoft Academic Search

This study effort was undertaken to determine the feasibility of using pelletized wood as an alternative fuel supply while retaining the capabilities of returning to the use of coal without interrupting steam production. Pelletized wood fuel was fired in two of four boilers rated at 80,000 pounds of steam per hour each. No modifications to the existing systems were required

Dohrer

1979-01-01

388

Morphological studies on neuroglia  

Microsoft Academic Search

Immunohistochemical studies with the use of the peroxidase-antiperoxidase (PAP) method revealed that “amoeboid microglial cells”, in the brains of neonatal rats and “brain macrophages” in lesioned brains of adult rats react positively to an antiserum raised against macrophages. In brains of neonatal rats, “amoeboid microglial cells” stained by means of the PAP-method were observed in the corpus callosum, internal capsule,

Y. Murabe; Y. Sano

1983-01-01

389

Parts application handbook study  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

390

Geostatistical case studies  

Microsoft Academic Search

The objective of this volume of contributed chapters is to present a series of applications of geostatistics. These range from a careful variographic analysis on uranium data, through detailed studies on geologically complex deposits, right up to the latest nonlinear methods applied to deposits with highly skewed data contributions. Applications of new techniques such as the external drift method for

G. Matheron; M. Armstrong

1987-01-01

391

Studies in Southwest Spanish.  

ERIC Educational Resources Information Center

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…

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

392

Future Titan Mission Studies  

Microsoft Academic Search

Exploration of Titan will remain a solar system science priority even (or especially) after Cassini. Not only does Titan offer an array of meteorological, oceanographical and geological phenomena richer than anywhere except Earth, but Titan's importance as an astrobiological target with a rich organic inventory has been long recognized. In-situ surface chemistry studies, meteorological and seismological monitoring and high-resolution geomorphological

R. Kakuda; T. Spilker; K. Baines; R. Lorenz

2002-01-01

393

Master Study: Ceramics  

ERIC Educational Resources Information Center

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.…

Clark, Kelly

2004-01-01

394

Cavitation studies in microgravity  

Microsoft Academic Search

The hydrodynamic cavitation phenomenon is a major source of erosion for many industrial systems such as cryogenic pumps for rocket propulsion, fast ship propellers, hydraulic pipelines and turbines. Erosive processes are associated with liquid jets and shockwaves emission fol-lowing the cavity collapse. Yet, fundamental understanding of these processes requires further cavitation studies inside various geometries of liquid volumes, as the

Philippe Kobel; Danail Obreschkow; Mohamed Farhat; Nicolas Dorsaz; Aurele de Bosset

2010-01-01

395

Connecticut Hurricane Evacuation Study.  

National Technical Information Service (NTIS)

This Hurricane Evacuation study is being conducted at the request of the State of Connecticut. The purpose of this investigation is to identify the areas and population within the State of Connecticut vulnerable to the effects of a potential hurricane lan...

1988-01-01

396

Booklet Classification Study.  

ERIC Educational Resources Information Center

Research studies using booklet classification were implemented by the American College Testing Program to investigate the linkage between the National Assessment of Educational Progress (NAEP) Achievement Levels Descriptions and the cutpoints set to represent student performance with respect to the achievement levels. This paper describes the…

Hanson, Bradley A.; Bay, Luz; Loomis, Susan Cooper

397

Pangnirtung: A Community Study.  

ERIC Educational Resources Information Center

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,…

Benyk, Pearl, Ed.

398

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...

399

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...

400

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 among the National Cancer Institute, the National Institute of Environmental Health Sciences, the U.S. Environmental Protection Agency and the National Institute for Occupational Safety and Health. 

401

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...

402

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 ...

403

A Feasibility Study.  

National Technical Information Service (NTIS)

A feasibility study has produced a sporozoite-induced rodent malaria test system that is based on the mortality rather than on the morbidity of negative controls. The test is performed with the NK65 strain of Plasmodium berghei, Anopheles stephensi and IC...

D. S. Rane

1975-01-01

404

Ethics and Study Abroad  

ERIC Educational Resources Information Center

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."…

Hoffa, William W.

2007-01-01

405

Hydrogasification Gas Processing Studies.  

National Technical Information Service (NTIS)

Three methods of separating hydrogen from methane and carbon monoxide were evaluated: use of a moving bed of activated carbon (hypersorption), use of cryogenics, and use of an ''absorbing oil'' to absorb the methane. The feed gas stream studied was the ma...

1978-01-01

406

Hydrogasification PDU studies  

SciTech Connect

Since April 1981, this ongoing study has completed (1) three hydrogasification tests using Florida peat, (2) experiments on the effect of dewatering technique on the hydrogasification of North Carolina sod peat, and (3) Sulzer belt-press dewatering of the Minnesota peat shipped to West Germany.

Not Available

1981-01-01

407

3?Critical Management Studies  

Microsoft Academic Search

Critical management studies (CMS) offers a range of alternatives to mainstream management theory with a view to radically transforming management practice. The common core is deep skepticism regarding the moral defensibility and the social and ecological sustainability of prevailing conceptions and forms of management and organization. CMS's motivating concern is neither the personal failures of individual managers nor the poor

Paul S. Adler; Linda C. Forbes; Hugh Willmott

2007-01-01

408

Studies in Manpower Planning.  

ERIC Educational Resources Information Center

This compilation consists of a collection of reports on models and studies in the area of manpower management and planning. Part One contains a doctoral dissertation, "The Application of Computer-Assisted Multi-Level Manpower Planning Models in the Federal Government" by R. J. Niehaus, which provides a comprehensive summary of the U.S. Navy's…

Charnes, A.; And Others

409

Study of Community Corrections.  

National Technical Information Service (NTIS)

Phase I of a two - year study of community corrections systems in the State of Colorado is presented to the State General Assembly by the Committee on Criminal Justice. Phase I involved the collection and analysis of available data on State and local corr...

1974-01-01

410

Rx for Social Studies.  

ERIC Educational Resources Information Center

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

Wheeler, Ron

1996-01-01

411

Studies in Vortex Dynamics.  

National Technical Information Service (NTIS)

This AASERT provided support for graduate student Kara Lavender who has just completed her fourth year of graduate study in physical oceanography. Ms. Lavender has been steadily working on the thesis project she proposed in her qualifying exam one year ag...

D. Rudnick G. Carnevale

1999-01-01

412

Planning for study abroad.  

PubMed

There is more to planning for study abroad than buying airplane tickets. Providing a successful course away from the host institution requires a great deal of planning by the educator. This planning includes course development, budget, marketing, travel, housing, food, and entertainment. Careful preparation provides both the educator and student a unique and enriching experience that goes beyond the traditional course. PMID:7862307

Freeman, L H; Hermann, C P

1994-01-01

413

Turbine blade damping study  

NASA Technical Reports Server (NTRS)

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.

Dominic, R. J.

1984-01-01

414

1991 NACUBO Endowment Study.  

ERIC Educational Resources Information Center

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…

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

415

Humanizing Home Study.  

ERIC Educational Resources Information Center

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

Hass, Glen; Fleury, Donna

416

LOS ANGELES CATALYST STUDY  

EPA Science Inventory

This report is a summary of the data collected at the Los Angeles Catalyst Study (LACS) from June 1974 through December 1977. Previous reports of the LACS data were presented at the symposium held in April 1977, covering the data through 1976. The current report follows the same ...

417

Case Studies in Biology.  

ERIC Educational Resources Information Center

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)

Zeakes, Samuel J.

1989-01-01

418

Repository seals requirements study  

SciTech Connect

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.

NONE

1997-11-03

419

Mirror reactor surface study  

Microsoft Academic Search

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are

A. L. Hunt; C. C. Damm; A. H. Futch; J. R. Hiskes; R. G. Meisenheimer; R. W. Moir; T. C. Simonen; B. W. Stallard; C. E. Taylor

1976-01-01

420

Linear Aerospike Engine Study.  

National Technical Information Service (NTIS)

Parametric data on split-combustor linear engine propulsion systems are presented for use in mixed-mode single-stage-to-orbit (SSTO) vehicle studies. Preliminary design data for two selected engine systems are included. The split combustor was investigate...

H. G. Diem F. M. Kirby

1977-01-01

421

Space Station Evolution Study.  

National Technical Information Service (NTIS)

This is the Space Station Freedom (SSF) Evolution Study 1993 Final Report, performed under NASA Contract NAS8-38783, Task Order 5.1. This task examined: (1) the feasibility of launching current National Space Transportation System (NSTS) compatible logist...

D. B. Evans

1993-01-01

422

Energetic Component Treatability Study  

Microsoft Academic Search

The effectiveness of three environmentally sound processes for small energetic component disposalwas examined experimentally in this study. The three destruction methods, batch reactorsupercritical water oxidation, sodium hydroxide base hydrolysis and calcium carbonate cookoff wereselected based on their potential for producing a clean solid residue and a minimum release of toxicgases after component detonation. The explosive hazard was destroyed by all

P. D. Gildea; S. L. Brandon; B. G. Brown; B. L. Haroldsen; J. Lipkin; W. C. Replogle; T. J. Shepodd; D. V. Zanini

1998-01-01

423

Energetic component treatability study  

Microsoft Academic Search

The effectiveness of three environmentally sound processes for small energetic component disposal was examined experimentally in this study. The three destruction methods, batch reactor supercritical water oxidation, sodium hydroxide base hydrolysis and calcium carbonate cookoff were selected based on their potential for producing a clean solid residue and minimum release of toxic gases after component detonation. The explosive hazard was

P. D. Gildea; S. L. Brandon; B. G. Brown

1997-01-01

424

Nesidioblastosis: a case study.  

PubMed

Hypoglycemia is a common problem among neonates. Transient in nature, it usually resolves with an increase in glucose intake. However, as clinicians, we must recognize that prolonged hypoglycemia may be caused by increased insulin production. Nesidioblastosis is one cause of persistent hyperinsulinism of the newborn. This case study reviews fetal physiology, neonatal presentation, and treatment. PMID:9325879

Starbuck, A L

1997-09-01

425

Acoustic Gravity Wave Study.  

National Technical Information Service (NTIS)

The report describes the efforts of the first four months of a one-year contract to study the propagation of acoustic gravity waves in the lower atmosphere and ionosphere, considering in particular the static firing of rocket engines and the occurrence of...

D. G. Detert C. A. Moo A. L. Oster W. E. Woolhiser

1967-01-01

426

Study of Vacuum Welding.  

National Technical Information Service (NTIS)

Vacuum cold welding and shear friction of several engineering materials was studied at extremely high vacuum levels above 10 to the -12th power torr in the temperature range 90 to 260 C with interface contact stresses up to 1000 psi. The effect of surface...

M. J. Hordon J. R. Roehrig

1967-01-01

427

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...

428

Caucasus: Self Study Guide.  

National Technical Information Service (NTIS)

The Self-Study Guide to the Caucasus (Armenia, Azerbaijan, Georgia and certain aspects of the North Caucasus, Russia) is intended to provide U.S. Government personnel in the foreign affairs community with an overview of important issues related to Caucasu...

A. van Oss

2004-01-01

429

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...

430

Social Studies: Grade 8.  

ERIC Educational Resources Information Center

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,…

Manitoba Dept. of Education, Winnipeg.

431

Physiological studies on Rhizobium  

Microsoft Academic Search

In recent years a number of investigations have been conducted to study the influence of u wide variety of materials upon the oxygen utilization of Rhizobium. The results secured, while giving indications of growth effects, furnish only a very incomplete picture of the physiological changes brought about by the organisms. In order to follow more closely the oxidative and reductive

D. W. Thorne; O. R. Neal; R. H. Walker

1936-01-01

432

Tethered gravity laboratories study  

NASA Technical Reports Server (NTRS)

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.

Lucchetti, F.

1989-01-01

433

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....

434

Soil washing treatability study  

SciTech Connect

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.

Krstich, M.

1995-12-01

435

Studies Probe Information Systems.  

ERIC Educational Resources Information Center

Summarizes the two recent studies of interest to the library community: (1) an A. D. Little analysis of past and present systems for dissemination of scientific technical information, and (2) Fritz Machlup's economic profile of key disseminators of scholarly, scientific, and intellectual knowledge. (FM)

Lynch, Mary Jo

1979-01-01

436

Waste energy recovery study  

Microsoft Academic Search

Part I of this report outlines the techniques used for determining appropriate schemes for energy recovery. Both thermodynamic and economic considerations are presented. Part 2 contains rejected-energy recovery studies for facilities, which are typical at most installations Part 3 is primarily concerned with special industrial recovery systems and most examples are a result of the Tinker AFB, OK, survey. Wright-Patterson

R. A. Golobic; D. A. Mrkvicka; H. C. Schlicht

1978-01-01

437

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...

438

MCE Field Study Project.  

ERIC Educational Resources Information Center

The effectiveness of six microcomputer programs designed for the secondary to adult population to teach concepts associated with daily living skills (vocations, elementary budgeting, money management assessment, banking, and home safety) was studied. These programs were field tested in special education classrooms in three different school…

Taber, Florence M.

439

Everglades Environmental Study Units.  

ERIC Educational Resources Information Center

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…

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

440

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...

441

Urban Expansion Study  

NASA Technical Reports Server (NTRS)

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.

1985-01-01

442

LIGHTPC Accuracy Study.  

National Technical Information Service (NTIS)

This report documents the results of a USAFETAC study of the accuracy of LIGHTPC and ICE PC small computer programs, both of which were used to compute astronomical data such as sunrise, sunset, moonrise, and moonset. It presents error distributions for p...

M. C. Peterson

1992-01-01

443

Admission Policy Impact Study.  

ERIC Educational Resources Information Center

This study reviews admissions policies at Oklahoma state colleges and universities to ensure that implementation of admission standards is consistent with the policy's intent and to document the impact of policy on student success. The report covers the period fall 1989 (the year prior to the phase-in of higher admission standards) to fall 1998.…

Oklahoma State Regents for Higher Education, Oklahoma City.

444

National Indian Education Study  

ERIC Educational Resources Information Center

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…

Harvey, Karen Kay

2006-01-01

445

Program of Studies. Foreword.  

ERIC Educational Resources Information Center

This bulletin provides a foreword to the Program of Studies series published by the Montgomery County, Maryland Public Schools. This series outlines the unified curriculum for students from kindergarten through high school. A statement of educational goals of the system and a discussion of educational standards and requirements for graduation from…

Montgomery County Public Schools, Rockville, MD. Dept. of Instructional Planning and Development.

446

CCD Signal Processor Study.  

National Technical Information Service (NTIS)

This report presents the results of a study of the application of charge coupled devices (CCD's) to radar signal processing systems. The particular radar problem considered was the detection of satellites at ranges of up to 25,000 NM. A CCD baseline desig...

L. W. Martinson B. P. Gaffney G. J. Mayer

1977-01-01

447

Tank Battalion Study.  

National Technical Information Service (NTIS)

The Tank Battalion Study is an analytical evaluation using the Close Combat Tactical Trainer (CCTT) at Ft Knox Ky. The tested alternative structures are the 4 company, 3 platoon, 3 tank per platoon and the 3 company, 3 platoon, 4 tank per platoon battalio...

D. Lindow T. Russell L. Vowels

2001-01-01

448

Election Studies in India  

Microsoft Academic Search

The election system is the pillar of Indian democracy. The system consists of various levels of elections to the Lok Sabha (the House of Representatives of the Union), State Legislative Assemblies, and Panchayati Raj Institutions (local self-governing bodies under State Governments). This article includes a review of studies related to the elections of Lok Sabha and State Legislative Assemblies conducted

Norio Kondo

2007-01-01

449

Creating a Study Guide.  

ERIC Educational Resources Information Center

Argues that making a theater study guide is an excellent in-class project, encouraging research, analysis, writing, and creative thinking. Offers a framework for creating one as a classroom project using John Steinbeck's "Of Mice and Men" as an example. Lists further resources. (SR)

Kelley, Laura C.

2001-01-01

450

SERT C project study  

NASA Technical Reports Server (NTRS)

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.

1974-01-01

451

Infrared Dye Laser Study.  

National Technical Information Service (NTIS)

Building on work done in Phase I of this study (See AD-748 863), research on near-infrared dye lasers continued along several lines. Eighteen more Kodak organic dyes were screened for laser action using a linear flash lamp for excitation. Six dyes lased b...

B. E. Plourde J. P. Webb

1973-01-01

452

Micromechanical Study of Metals  

NASA Technical Reports Server (NTRS)

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.

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

1945-01-01

453

Screen Study Guides.  

ERIC Educational Resources Information Center

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…

Duncan, Barry

1969-01-01

454

General Aviation Manpower Study.  

ERIC Educational Resources Information Center

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

Feller, Richard

1982-01-01

455

Vasectomy Camps: A Study.  

National Technical Information Service (NTIS)

This report has three parts. The first part deals with the demographic and socioeconomic characteristics of the acceptors of vasectomy and tubectomy in different camps in India. Studies included in this part have been arranged state-wide. The second part ...

1973-01-01

456

Aircraft EMP isolation study  

NASA Astrophysics Data System (ADS)

This report presents the results of a preliminary study into methods for electrically isolating the E-4B, the EC-135, and the EC-130 aircraft during EMP tests where the aircraft under test is directly driven by a high-voltage pulser.

Finci, A.; Price, H.; Chao, P.; Mercer, S.; Naff, T.

1980-07-01

457

Rain Attenuation Studies.  

National Technical Information Service (NTIS)

The statistical properties of rain attenuation which dominate propogation at frequencies above 10 GHz are required for planning radio systems at these frequencies. These properties are studied for three frequencies, 11.2, 12.7 and 18.76 GHz and various li...

G. Drufuca

1973-01-01

458

Study Blasts Leadership Preparation  

ERIC Educational Resources Information Center

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…

Archer, Jeff

2005-01-01

459

Faculty Retention Study, 2002.  

ERIC Educational Resources Information Center

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

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

460

Geosynchronous Technology Infusion Studies  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

461

Legal Studies and Mediation.  

ERIC Educational Resources Information Center

The dispute resolution center at the University of Massachusetts illustrates how a legal studies program can form the basis for conflict resolution in the local community as well as on campus. The center draws heavily on the skills and experience of individuals in both the academic and public sectors. (MLW)

Rifkin, Janet; And Others

1980-01-01

462

NACUBO Endowment Study, 1998.  

ERIC Educational Resources Information Center

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

Cambridge Associates, Inc., Boston, MA.

463

Digital communications study  

NASA Technical Reports Server (NTRS)

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.

Boorstyn, R. R.

1973-01-01

464

Recycling Study Guide.  

ERIC Educational Resources Information Center

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…

Hallowell, Anne; And Others

465

Acid Rain Study Guide.  

ERIC Educational Resources Information Center

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…

Hunger, Carolyn; And Others

466

Social Studies Journal, 2003.  

ERIC Educational Resources Information Center

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

West, Leo R., Ed.

2003-01-01

467

Charter School Achievement Studies  

Microsoft Academic Search

A study on charter school performance always makes for a good news story. Unfortunately, like many press reports on medicine and other scientific issues, stories about student achievement in charter schools are premature and often misleading. Americans are just now starting to ask tough questions about the effectiveness of particular schools and to keep and analyze the hard data needed.

Paul T. Hill; Lawrence Angel; Jon Christensen

2006-01-01

468

Central American resource studies  

Microsoft Academic Search

Los Alamos National Laboratory has been working with five Central American countries to assist in the development of their energy and mineral resources. Since 1985, mineral resources in Costa Rica, peat resources in Costa Rica and Panama, geothermal energy resources in Honduras and Guatemala, and geothermal field development in El Salvador and Costa Rica have been topics of study. This

E. Van Eeckhout; A. W. Laughlin

1989-01-01

469

Magnetic Techniques Study.  

National Technical Information Service (NTIS)

The objective of this feasibility study was to provide the capability to encode data magnetically on new passports and this data be frozen i.e. -- once encoded the information should be incapable of being altered, supplemented or erased. This work was und...

A. A. Greene S. T. C. Chen L. T. Farris

1977-01-01

470

Polymer infiltration studies  

NASA Technical Reports Server (NTRS)

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.

Marchello, Joseph M.

1992-01-01

471

Skin Cancer Prevention Study  

Cancer.gov

Actinic keratoses (AKs) are precancerous skin growths that are usually caused by sun exposure. This study seeks to determine if the drug celecoxib prevents new AKs from developing, causes existing AKs to go away, and prevents AKs from progressing to squamous cell cancer.

472

Demography & Population Studies  

NSDL National Science Digital Library

Coombs Computing Unit at the Australian National University, Canberra now administers CERN's Virtual Library page on Demography & Population Studies. The server has links to 105 sites worldwide which may be of interest to demography and population researchers and others. Listings are nicely organized by access method.

473

FlexiStudy.  

ERIC Educational Resources Information Center

FlexiStudy is a new type of correspondence course developed by the National Extension College, which has become a center for the production and distribution of distance learning materials, while local colleges take the responsibility for teaching, counseling, and administration. (EAO)

Freeman, Richard

1982-01-01

474

Why Indigenous Nations Studies?  

ERIC Educational Resources Information Center

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

Porter, Robert; Yellow Bird, Michael

2000-01-01

475

Autism\\/excel study  

Microsoft Academic Search

Five high school students with ASD (autistic spectrum disorder) participating in the Excel\\/Autism study were able to demonstrate mastery of a set of Excel topics. The Excel curriculum covered approximately the same topics as are covered in the Excel portion of Computer Business Applications, a class for regular education students at Fox Chapel Area High School, a high school in

Mary Hart

2005-01-01

476

Laboratory and simulation studies  

Microsoft Academic Search

The study of Solar System bodies by remote and in situ measurements provides information about geological, chemical and physical properties of materials present in different space environments. Processes (e.g., thermal annealing, UV irradiation, ion bombardment, gas-solid interaction) contribute with different efficiencies to determine the characteristics of materials, depending on both the local environment properties and on the sensitivity of species

L. Colangeli; R. Battaglia; J. R. Brucato; V. della Corte; A. Esposito; F. Esposito; G. Ferrini; E. Mazzotta Epifani; V. Mennella; E. Palomba; P. Palumbo; A. Rotundi

2002-01-01

477

Conducting Student Retention Studies.  

ERIC Educational Resources Information Center

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…

Ewell, Peter T.

478

Study of Vacuum Welding.  

National Technical Information Service (NTIS)

Cold welding between aluminum, copper, stainless steel (440 C and 17-4 PH), and tungsten carbide was studied experimentally over the temperature range of 90 to 260 C with interface contact stresses at 0,100 and 1000 psi under extremely low pressures about...

F. J. Brock L. G. Fasolino M. J. Hordon

1965-01-01

479

Advanced Antitorque Concepts Study.  

National Technical Information Service (NTIS)

The report summarizes a study of possible alternatives to the tail rotor on single-rotor shaft-driven helicopters. The objective was to select concepts that show improvements over the tail rotor in high-speed dynamics, vulnerability, reliability and maint...

A. W. Grumm G. E. Herrick

1971-01-01

480

Studies in Battle Command.  

National Technical Information Service (NTIS)

In response to the recent Battle Command Initiative at Headquarters U.S. Army Training and Doctrine Command, the faculty of the Combat Studies Institute at the U.S. Army Command and General Staff College wrote a series of essays analyzing various combat e...

1995-01-01

481

Vocational Teacher Education Study.  

ERIC Educational Resources Information Center

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

Tulloch, Charlotte

482

Collaboration through Study Circles  

ERIC Educational Resources Information Center

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

McCoy, Martha L.

2005-01-01

483

Ecological Field Studies  

ERIC Educational Resources Information Center

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…

Dobson, Christopher

2008-01-01

484

Antibodies for CFTR studies  

Microsoft Academic Search

Abstract For most expression studies focusing on the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, sensitive and specific antibodies (Abs) are critically needed. Several Abs have been produced commercially,or by research laboratories for CFTR detection in both cell lines with heterologous or endogenous expression and native cells\\/tissues. Here, we review the applicability of most Abs currently in use in CF

Filipa Mendes; Carlos M. Farinha; M Onica Roxo-rosa; Pascale Fanen; Aleksander Edelman; Robert Dormer; Margaret Mcpherson; Heather Davidson; Edith Puchelle; Hugo De Jonge; Ghanshyam D. Heda; Martina Gentzsch; Gergely L. Lukacs; Deborah Penque; Margarida D. Amaral

485

Antibodies for CFTR studies  

Microsoft Academic Search

For most expression studies focusing on the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, sensitive and specific antibodies (Abs) are critically needed. Several Abs have been produced commercially or by research laboratories for CFTR detection in both cell lines with heterologous or endogenous expression and native cells\\/tissues. Here, we review the applicability of most Abs currently in use in CF

Filipa Mendesa; Carlos M. Farinhaa; Pascale Fanenc; Robert Dormere; Ghanshyam D. Hedai; Gergely L. Lukacsk; Margarida D. Amarala; Ricardo Jorge; S. C. Johnson

486

Antibodies for CFTR studies  

Microsoft Academic Search

For most expression studies focusing on the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, sensitive and specific antibodies (Abs) are critically needed. Several Abs have been produced commercially or by research laboratories for CFTR detection in both cell lines with heterologous or endogenous expression and native cells\\/tissues. Here, we review the applicability of most Abs currently in use in CF

Filipa Mendes; Carlos M. Farinha; Mónica Roxo-Rosa; Pascale Fanen; Aleksander Edelman; Robert Dormer; Margaret McPherson; Heather Davidson; Edith Puchelle; Hugo De Jonge; Ghanshyam D. Heda; Martina Gentzsch; Gergely Lukacs; Deborah Penque; Margarida D. Amaral

2004-01-01

487

Study of Boundary Structures.  

National Technical Information Service (NTIS)

The project extends previous studies on structures of a 2-D grain boundary (g.b.). The basic analytical tool is the cluster variation method (CVM) and the path probability method (PPM), both developed by the author. In the CVM, the free energy is minimize...

R. Kikuchi

1987-01-01

488

Remote connector development study  

SciTech Connect

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.

Parazin, R.J.

1995-05-01

489

Fundamental Pyrolysis Studies  

SciTech Connect

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.

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

1983-03-01

490

2007 CEO Compensation Study  

NSDL National Science Digital Library

Charity Navigator provides high-quality information about charities in order "to advance a more efficient and responsive philanthropic marketplace." One of the more recently published studies is the 2007 CEO Compensation Study. Visitors can read this annotated report here in its entirety, and it contains a wealth of information about the subject. In the year 2007, their research shows that the top leaders of the 5242 largest charities in America earn an average salary of $145,270. While this amount may strike some as rather large, the report also notes that CEO compensation accounts for just 3.37% of the average organization's spending. The report contains a number of helpful charts, such as those that list average CEO salary by geographic region and by size of charity.

2007-08-01

491

STUDIES ON MALARIAL PARASITES  

PubMed Central

1. Methods of recovering adequate amounts of Plasmodium knowlesi from the monkey (Macaca, mulatta) for biochemical studies and in vitro cultivation are described. Concentrates of red blood cells parasitized with P. knowlesi can be obtained by differential sedimentation of parasitized blood because of physical and chemical changes produced by the parasites in the host cell and the plasma of the blood. 2. Two different techniques, the rocker-dilution and the rocker-perfusion methods, are described for the cultivation of malarial parasites. Details of the apparatus, assembly, and sterilization are given, as well as methods of counting and evaluating parasites. 3. In a series of 235 control experiments for 20 to 24 hours using three types of apparatus, the average rate of multiplication was 3.9. Each technique has specific value for studying the various aspects of metabolism, nutrition, and the action of antimalarial drugs.

Geiman, Quentin M.; Anfinsen, Christian B.; McKee, Ralph W.; Ormsbee, Richard A.; Ball, Eric G.

1946-01-01

492

LOXT mirror design study  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

493

Repository seals requirement study  

SciTech Connect

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

NONE

1997-11-03

494

Rotating gravity gradiometer study  

NASA Technical Reports Server (NTRS)

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

Forward, R. L.

1976-01-01

495

Studies of magnetopause structure  

NASA Technical Reports Server (NTRS)

From the International Sun-Earth Explorers (ISEE) 1 magnetopause crossings on November 10, 1977, three-dimensional distribution functions for energetic ions were studied in the magnetosphere, through the magnetopause, and in the magnetosheath (Speiser and Williams, 1982). The particle distributions were particularly examined at and near the times that Russell and Elphic (1978) identified as flux transfer events (FTE). Using a simple, one-dimensional, quasi-static model, particle orbits were followed numerically, from the magnetosphere into the sheath. The inner, trapped, distribution initializes the distribution function. Liouville's theorem allows the inner distribution to be mapped into the sheath following the orbits. This mapping is shown for four mangetosheath ion flows (MIF's) corresponding to four flux transfer events. Results from the studies are discussed. A brief discussion of current sheet particle motion is presented.

Speiser, Theodore W.

1991-01-01

496

Study Thermographic Flaw Detection  

NASA Technical Reports Server (NTRS)

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.

Walker, James L.; Workman, Gary L.

1996-01-01

497

Study Thermographic Flaw Detection  

NASA Technical Reports Server (NTRS)

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.

Walker, James L.; Workman, Gary L.

1996-01-01

498

Postmortem studies in schizophrenia  

PubMed Central

For over a century, postmortem studies have played a central part in the search for the structural and biochemical pathology of schizophrenia. However, for most of this time, little progress has been made. Recently, the situation has begun to change, helped by the emergence of more powerful methodologies and research designs, and by the availability of brain imaging to provide complementary information. As a result, it can now be clearly concluded that there are structural cerebral abnormalities in schizophrenia that are intrinsic to the disorder. The neuropathological process is not primarily degenerative, but involves a change in the normal cytoarchitecture of the brain, probably originating in development. Neurochemically, there is postmortem evidence for alterations in several transmitter systems including dopamine, glutamate, serotonin, and ?-aminobutyric acid (GABA). The cardinal findings are reviewed here, together with a consideration of the conceptual and methodological issues that face postmortem studies of schizophrenia.

Harrison, Paul J.

2000-01-01

499

PSU Case Studies  

NSDL National Science Digital Library

How does one teach ethics? It can be a difficult subject and different fields (medicine, law, and so on) all have different ethical considerations and issues. This fine collection of engineering case studies from the Pennsylvania State University College of Engineering brings together resources from a variety of universities that have worked to address this matter. The cases are divided into separate areas that include Developing and Using Case Studies, General Science Cases, and Research Integrity Cases. Visitors shouldn't miss the bulk of the material covered in the General Engineering Cases area, which includes high-quality and contemplative materials on engineering practice ethics from SUNY-Buffalo and the National Science Foundation. The site is rounded out by a number of helpful cases developed in-house by Penn State engineering students.

2013-04-26

500

EUROv Super Beam Studies  

SciTech Connect

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.

Dracos, Marcos [IPHC, Universite de Strasbourg, CNRS/IN2P3, F-67037 Strasbourg (France)

2011-10-06