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Sample records for earth quadrupolar effects

  1. Quadrupolar Kondo effect in uranium heavy-electron materials?

    NASA Technical Reports Server (NTRS)

    Cox, D. L.

    1987-01-01

    The possibility of an electric quadrupole Kondo effect for a non-Kramers doublet on a uranium (U) ion is a cubic metallic host is demonstrated by model calculations showing a Kondo upturn in the resistivity, universal quenching of the quadrupolar moment, and a heavy-electron anomaly in the electronic specific heat. With inclusion of excited crystal-field levels, some of the unusual magnetic-response data in the heavy-electron superconductor UBe13 may be understood. Structural phase transitions at unprecedented low temperatures may occur in U-based heavy-electron materials.

  2. Effects of the quadrupolar interaction in Γ3-Γ4 systems observed through a reduced model

    NASA Astrophysics Data System (ADS)

    von Ranke, P. J.; Caldas, A.; de Oliveira, N. A.; Palermo, L.

    1997-07-01

    We study the magnetism of PrX2 intermetallic compounds (X = Rh, Al, Ru Mg) on the basis of a Hamiltonian which includes the quadrupolar interaction in addition to the magnetic and crystal field interactions. The calculations are carried out through a reduced model in which we neglect the highest energy levels of the ground state multiplet of the Pr ion. In this simplified picture, we obtain an analytic expression for the magnetic state equation. This equation is used to investigate how the quadrupolar interaction affects the nature of the magnetic phase transition. We also investigate the effects of the quadrupolar interaction on the behaviour of the gyromagnetic and dipolar exchange parameters in the present PrX2 compounds.

  3. Quadrupolar and anisotropy effects on dephasing in two-electron spin qubits in GaAs

    PubMed Central

    Botzem, Tim; McNeil, Robert P. G.; Mol, Jan-Michael; Schuh, Dieter; Bougeard, Dominique; Bluhm, Hendrik

    2016-01-01

    Understanding the decoherence of electron spins in semiconductors due to their interaction with nuclear spins is of fundamental interest as they realize the central spin model and of practical importance for using them as qubits. Interesting effects arise from the quadrupolar interaction of nuclear spins with electric field gradients, which have been shown to suppress diffusive nuclear spin dynamics and might thus enhance electron spin coherence. Here we show experimentally that for gate-defined GaAs quantum dots, quadrupolar broadening of the nuclear Larmor precession reduces electron spin coherence by causing faster decorrelation of transverse nuclear fields. However, this effect disappears for appropriate field directions. Furthermore, we observe an additional modulation of coherence attributed to an anisotropic electronic g-tensor. These results complete our understanding of dephasing in gated quantum dots and point to mitigation strategies. They may also help to unravel unexplained behaviour in self-assembled quantum dots and III–V nanowires. PMID:27079269

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

    SciTech Connect

    Urban, Jeffry Todd

    2004-01-01

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

  5. Interaction of Strain and Nuclear Spins in Silicon: Quadrupolar Effects on Ionized Donors

    NASA Astrophysics Data System (ADS)

    Franke, David P.; Hrubesch, Florian M.; Künzl, Markus; Becker, Hans-Werner; Itoh, Kohei M.; Stutzmann, Martin; Hoehne, Felix; Dreher, Lukas; Brandt, Martin S.

    2015-07-01

    The nuclear spins of ionized donors in silicon have become an interesting quantum resource due to their very long coherence times. Their perfect isolation, however, comes at a price, since the absence of the donor electron makes the nuclear spin difficult to control. We demonstrate that the quadrupolar interaction allows us to effectively tune the nuclear magnetic resonance of ionized arsenic donors in silicon via strain and determine the two nonzero elements of the S tensor linking strain and electric field gradients in this material to S11=1.5 ×1022 V /m2 and S44=6 ×1022 V /m2 . We find a stronger benefit of dynamical decoupling on the coherence properties of transitions subject to first-order quadrupole shifts than on those subject to only second-order shifts and discuss applications of quadrupole physics including mechanical driving of magnetic resonance, cooling of mechanical resonators, and strain-mediated spin coupling.

  6. Quadrupolar Effect on Two Layered Thin Film Antiferroelectric Smectic Liquid Crystal

    SciTech Connect

    Lum, Chia-Yuee; Ong, Lye-Hock; Cepic, Mojca

    2011-03-30

    Within the framework of the discrete Landau phenomenological model, the free energy of an antiferroelectric smectic liquid crystal is analyzed. This model considers the interactions between the liquid crystal molecules within the nearest and the next nearest layers. Electrostatic quadrupolar interaction up to the nearest layers is included. This quadrupolar term, b{sub q{xi}}???{sub i{center_dot}{xi}}???{sub i+1}{sup 2} is positive, thus favouring a perpendicular orientation in the adjacent layer respectively. We show how quadrupolar interaction can affects the planar regions of the phase diagram of a two layered thin antiferroelectric smectic liquid crystal film.

  7. The Effect of Tidal Friction and Quadrupolar Distortion on Orbits of Stars or Planets in Hierarchical Triple systems

    NASA Astrophysics Data System (ADS)

    Kiseleva, L. G.; Eggleton, P. P.

    In hierarchical triple stars, such as lambda Tau and beta Per the combination of a) fluctuating eccentricity due to the third body and b) tidal friction, mainly within the close pair, which tries to remove such fluctuations, can lead to potentially large but slow secular changes in orbital parameters. We model the orbits of both the above systems using a force law which includes a combination of point-mass gravity, quadrupolar distortion of each star by the other two, and a dissipative tidal-friction term. For lambda Tau we find a preferred model where expansion of the inner orbit due to mass transfer on a nuclear timescale is balanced by contraction because tidal friction transfers angular momentum from the inner to the outer orbit. In beta Per, the two orbits are nearly orthogonal (i=100 deg), and the effect of the third star would periodically increase the inner eccentricity up to nearly unity if we neglect the effects of quadrupolar distortion and tidal friction. In fact, in beta Per quadrupolar distortion alone can almost completely suppress the inner eccenticity fluctuations. In a hypothetcal zero-age state of this system, when the inner binary can be supposed to be well-detached, we find large fluctuations in eccentricity which, on being damped by tidal friction, lead to shrinkage of the inner orbit on a surprisingly short timescale. However, the shrinkage is halted by the fact that as the inner pair becomes closer they become more distorted: this quadrupolar distortion leads to apsidal motion which prevents further large fluctuations in eccentricity. In hypothetical cases of nearly orthogonal triple systems with one component of the close pair being a Jupiter-like planet, the combined effect of quadrupolar distortion and tidal friction may reduce the fluctuations of the inner eccentricity, and in some cases the Jupiter orbit can in principle be shrunk quite drastically over a suitably long interval of time. This is potentially important for the long

  8. Magnetic Structure and Quadrupolar Order Parameter Driven by Geometrical Frustration Effect in NdB4

    NASA Astrophysics Data System (ADS)

    Yamauchi, Hiroki; Metoki, Naoto; Watanuki, Ryuta; Suzuki, Kazuya; Fukazawa, Hiroshi; Chi, Songxue; Fernandez-Baca, Jaime A.

    2017-04-01

    Neutron diffraction experiments have been carried out to characterize the magnetic structures and order parameters in an intermediate phase of NdB4 showing the successive phase transitions at T0 = 17.2 K, TN1 = 7.0 K, and TN2 = 4.8 K. We have revealed the antiferromagnetic ordering with the propagation vectors q0 = (0,0,0), q0 and qs1 = (δ ,δ ,0.4) (δ ˜ 0.14), and q0 and qs2 = (0.2,0,0.4) in phase II (TN1 < T < T0), phase III (TN2 < T < TN1), and phase IV (T < TN2), respectively. The observed patterns in phase II are successfully explained by postulating a coplanar structure with static magnetic moments in the tetragonal ab-plane. We have found that the magnetic structure in phase II can be uniquely determined to be a linear combination of antiferromagnetic "all-in/all-out"-type (Γ4) and "vortex"-type (Γ2) structures, consisting of a Γ4 main component (77%) with a small amplitude of Γ2 (23%). We propose that the quadrupolar interaction holds the key to stabilizing the noncollinear magnetic structure and quadrupolar order. Here, the frustration in the Shastry-Sutherland lattice would play an essential role in suppressing the dominance of the magnetic interaction.

  9. Earth's magnetic field enabled scalar coupling relaxation of 13C nuclei bound to fast-relaxing quadrupolar 14N in amide groups.

    PubMed

    Chiavazza, Enrico; Kubala, Eugen; Gringeri, Concetta V; Düwel, Stephan; Durst, Markus; Schulte, Rolf F; Menzel, Marion I

    2013-02-01

    Scalar coupling relaxation, which is usually only associated with closely resonant nuclei (e.g., (79)Br-(13)C), can be a very effective relaxation mechanism. While working on hyperpolarized [5-(13)C]glutamine, fast liquid-state polarization decay during transfer to the MRI scanner was observed. This behavior could hypothetically be explained by substantial T(1) shortening due to a scalar coupling contribution (type II) to the relaxation caused by the fast-relaxing quadrupolar (14)N adjacent to the (13)C nucleus in the amide group. This contribution is only effective in low magnetic fields (i.e., less than 800 μT) and prevents the use of molecules bearing the (13)C-amide group as hyperpolarized MRS/MRI probes. In the present work, this hypothesis is explored both theoretically and experimentally. The results show that high hyperpolarization levels can be retained using either a (15)N-labeled amide or by applying a magnetic field during transfer of the sample from the polarizer to the MRI scanner.

  10. Effect of strongly coupled plasma on the magnetic dipolar and quadrupolar transitions of two-electron ions

    SciTech Connect

    Saha, Jayanta K.; Mukherjee, T. K.; Mukherjee, P. K.; Fricke, B.

    2013-04-15

    Effect of strongly coupled plasma on the excitation energies and transition probabilities for the respective transitions 1s{sup 2}:{sup 1}S{sup e}{yields} 1sns:{sup 3}S{sup e} (n = 2, 3, 4) and 1s{sup 2}:{sup 1}S{sup e}{yields} 1snp:{sup 3}P{sup o} (n = 2, 3, 4) allowed by magnetic dipolar and quadrupolar excitations have been analyzed for the first time for the two-electron ions C{sup 4+}, O{sup 6+}, Ne{sup 8+}, Mg{sup 10+}, Si{sup 12+}, and S{sup 14+}. Time dependent Hatree-Fock theory within variational approach has been adopted for such a study. The effect of surrounding plasma has been treated through the standard Ion-Sphere (IS) model of the plasma where the plasma density is varied systematically from a low value to a pretty high value such that the respective excited states go over to continuum due to such a confinement. The effect of external pressure generated due to plasma confinement on the estimated spectral properties has been analyzed systematically.

  11. Relaxation Effects in a System of a Spin-1solar2 Nucleus Coupled to a Quadrupolar Spin Subjected to RF Irradiation: Evaluation of Broadband Decoupling Schemes

    NASA Astrophysics Data System (ADS)

    Smith, Scott A.; Murali, Nagarajan

    1999-01-01

    We have investigated the suitability and performance of various decoupling methods on systems in which an observed spin-1/2 nucleusI(13C or15N) is scalar-coupled to a quadrupolar spinS(2H). Simulations and experiments have been conducted by varying the strength of the irradiating radiofrequency (RF) field, RF offset, relaxation times, and decoupling schemes applied in the vicinity of theS-spin resonance. TheT1relaxation of the quadrupolar spin has previously been shown to influence the efficiency of continuous wave (CW) decoupling applied on resonance in such spin systems. Similarly, the performance of broadband decoupling sequences should also be affected by relaxation. However, virtually all of the more commonly used broadband decoupling schemes have been developed without consideration of relaxation effects. As a consequence, it is not obvious how one selects a suitable sequence for decoupling quadrupolar nuclei with exotic relaxation behavior. Herein we demonstrate that, despite its simplicity, WALTZ-16 decoupling is relatively robust under a wide range of conditions. In these systems it performs as well as the more recently developed decoupling schemes for wide bandwidth applications such as GARP-1 and CHIRP-95. It is suggested that in macromolecular motional regimes, broadband deuterium decoupling can be achieved with relatively low RF amplitudes (500-700 Hz) using WALTZ-16 multiple pulse decoupling.

  12. Two-Photon Absorption and Fluorescence with Quadrupolar and Branched CHROMOPHORES—EFFECT of Structure and Branching

    NASA Astrophysics Data System (ADS)

    Porrès, Laurent; Mongin, Olivier; Katan, Claudine; Charlot, Marina; Bhatthula, Bharath Kumar Goud; Jouikov, Viatcheslav; Pons, Thomas; Mertz, Jerome; Blanchard-Desce, Mireille

    The photophysical and two-photon absorption (TPA) properties of three homologous quadrupolar and one related three-branched chromophores were investigated. Design of the quadrupoles is based on the symmetrical functionalization of a biphenyl core. Modulation of the nonlinear absorptivity/transparency/photostability trade-off can be achieved by playing with the twist angle of the core and on the spacers (phenylene-vinylene versus phenylene-ethynylene). The quadrupolar chromophores combine high TPA cross-sections, high fluorescence quantum yield and solvent sensitive photoluminescence properties. The branched structure exhibits spectrally broadened TPA in the NIR region (up to 3660 GM at 740 nm measured in the femtosecond regime) but reduced sensitivity to the environment.

  13. Quadrupolar effects on nuclear spins of neutral arsenic donors in silicon

    NASA Astrophysics Data System (ADS)

    Franke, David P.; Pflüger, Moritz P. D.; Mortemousque, Pierre-André; Itoh, Kohei M.; Brandt, Martin S.

    2016-04-01

    We present electrically detected electron nuclear double resonance measurements of the nuclear spins of ionized and neutral arsenic donors in strained silicon. In addition to a reduction of the hyperfine coupling, we find significant quadrupole interactions of the nuclear spin of the neutral donors of the order of 10 kHz. By comparing these to the quadrupole shifts due to crystal fields measured for the ionized donors, we identify the effect of the additional electron on the electric field gradient at the nucleus. This extra component is expected to be caused by the coupling to electric field gradients created due to changes in the electron wave function under strain.

  14. Gyroscopic effect in low-energy classical capture of a rotating quadrupolar diatom by an ion.

    PubMed

    Dashevskaya, Elena; Litvin, Iliya; Nikitin, Evgueni

    2006-03-09

    The low-energy capture of homonuclear diatoms by ions is due mainly to the long-range part of the interpartner potential with leading terms that correspond to charge-quadrupole interaction and charge-induced dipole interaction. The capture dynamics is described by the perturbed-rotor adiabatic potentials and the Coriolis interaction between manifold of states that belong to a given value of the intrinsic angular momentum. When the latter is large enough, it can noticeably affect the capture cross section calculated in the adiabatic channel approximation due to the gyroscopic property of a rotating diatom. This paper presents the low-energy (low-temperature) state-selected partial and mean capture cross sections (rate coefficients) for the charge-quadrupole interaction that include the gyroscopic effect (decoupling of intrinsic angular momentum from the collision axis), quantum correction for the diatom rotation, and the correction for the charge-induced dipole interaction. These results complement recent studies on the gyroscopic effect in the quantum regime of diatom-ion capture (Dashevskaya, E. I.; Litvin, I.; Nikitin, E. E.; Troe, J. J. Chem. Phys. 2004, 120, 9989-9997).

  15. Resonant spectra of quadrupolar anions

    NASA Astrophysics Data System (ADS)

    Fossez, K.; Mao, Xingze; Nazarewicz, W.; Michel, N.; Garrett, W. R.; Płoszajczak, M.

    2016-09-01

    In quadrupole-bound anions, an extra electron is attached at a sufficiently large quadrupole moment of a neutral molecule, which is lacking a permanent dipole moment. The nature of the bound states and low-lying resonances of such anions is of interest for understanding the threshold behavior of open quantum systems in general. In this work, we investigate the properties of quadrupolar anions as halo systems, the formation of rotational bands, and the transition from a subcritical to supercritical electric quadrupole moment. We solve the electron-plus-rotor problem using a nonadiabatic coupled-channel formalism by employing the Berggren ensemble, which explicitly contains bound states, narrow resonances, and the scattering continuum. The rotor is treated as a linear triad of point charges with zero monopole and dipole moments and nonzero quadrupole moment. We demonstrate that binding energies and radii of quadrupolar anions strictly follow the scaling laws for two-body halo systems. Contrary to the case of dipolar anions, ground-state band of quadrupolar anions smoothly extend into the continuum, and many rotational bands could be identified above the detachment threshold. We study the evolution of a bound state of an anion as it dives into the continuum at a critical quadrupole moment and we show that the associated critical exponent is α =2 . Everything considered, quadrupolar anions represent a perfect laboratory for the studies of marginally bound open quantum systems.

  16. Quadrupolar Echo Spectra of the Tunneling CD 3Group

    NASA Astrophysics Data System (ADS)

    Olejniczak, Z.; Detken, A.; Manz, B.; Haeberlen, U.

    Deuteron NMR spectra of both single crystal and powder samples of acetylsalicylic acid-CD 3were measured using the quadrupolar-echo technique. The experiments were done in the temperature range 17-100 K, with a special emphasis on the range 20- 30 K, in which the observable tunneling frequency decreases rapidly from its low-temperature value of 2.7 down to 1.2 MHz. In the tunneling regime, modulations of the line intensities and phases as a function of the echo time τ are observed in the single-crystal spectra. The modulation frequency is equal to the orientation-dependent displacement of the inner satellite pairs (α lines) from the Larmor frequency. These effects were confirmed in numerical simulations and fully explain the phase-modulation effects observed previously in quadrupolar-echo spectra of methyl-deuterated methanol and para-xylene guest molecules in some inclusion compounds. By measuring the temperature and orientation dependence of the quadrupolar lineshapes, it was found that the echo spectra are more sensitive to the value of the tunneling frequency than the spectra obtained from the free induction decay. It is pointed out that, because of the modulation effects, special care must be taken when structural parameters are to be extracted from quadrupolar-echo spectra, in particular from spectra of powder samples.

  17. A continuum theory of solvation in quadrupolar solvents. I. Formulation

    NASA Astrophysics Data System (ADS)

    Jeon, Jonggu; Kim, Hyung J.

    2003-10-01

    A continuum theory to describe equilibrium and nonequilibrium solvation in polarizable, nondipolar, quadrupolar solvents is developed. By employing the densities of the solvent quadrupole and induced dipole moments as primary field variables, a reaction field theory formulation for quadrupolar solvents is constructed with account of their electronic polarizability. Nonequilibrium solvation aspects are effected via the solvent coordinate description for the quadrupole moment density. It is found that the theory is consistent with the macroscopic Maxwell equations and satisfies the continuity of the electric potential across the cavity boundaries. Solvation stabilization arising from the solvent quadrupoles is captured via novel reaction field factors analogous to those for dipolar solvents. Comparison is made with the dielectric continuum description of the polarizable, dipolar solvents as well as with previous theories of the quadrupolar solvents. Extensions and applications of the current theoretical formulation to study free energetics and dynamics of reactive and spectroscopic processes in the quadrupolar solvents are reported in the following paper [J. Jeon and H. J. Kim, J. Chem. Phys. 119, 8626 (2003)].

  18. Quadrupolar Interactions in Praseodymium - SILVER(1 - Copper(x)

    NASA Astrophysics Data System (ADS)

    Gotaas, James Alan

    We have utilized magnetization, specific heat, resistivity and diffraction experiments (each as a function of applied magnetic field and temperature) to investigate the magnetic properties of the series of pseudo-binary rare earth-intermetallic compounds PrAg(,1-x)Cu(,x) (for x = 0, 0.15, 0.25, 0.35, 0.4, 0.5, 0.75 and 1.0). For 0 <= x <= 0.4, the samples possess a CsCl -type (cubic) crystal structure and exhibit antiferromagnetic ordering at low temperatures (T(,N) < 11K), as revealed by x-ray and neutron diffraction and magnetization measurements. For x = 0.75 and 1.0, the crystal structure is FeB-type (orthorhombic) and no magnetic ordering occurs for T > 2K. For x = 0.5, the sample undergoes a structural transition from CsCl - to FeB-type upon cooling below 160K. Analysis of magnetization measurements reveals that, in addition to the typical bilinear exchange interactions, the CsCl-type compounds also possess effective negative quadrupolar interactions which increase in magnitude by a factor of five as x increases from 0 to 0.4. Such negative (antiferroquadropolar) interactions favor quadrature alignment of neighboring quadrupoles. Specific heat and resistivity measurements indicate that the magnetic order-disorder transition for x = 0 is a typical antiferromagnetic-paramagnetic transition, displaying a sharp peak in C(,m) vs T and a well-defined spin-disorder contribution to the resistivity. As x increases, however, the peak in the magnetic specific heat broadens and decreases in magnitude, accompanied by a change in the rate of development of entropy and a change in the nature of the magnetic excitations in the ordered state. In addition, the change in the resistivity at the magnetic transition becomes more gradual, and the apparent spin-disorder terms becomes a factor of four smaller. The effective quadrupolar interactions in these systems linked to incipient structural instabilities in the CsCl-type structure which ultimately lead to the structural

  19. The Effect of Magnetic Field Inhomogeneity on the Transverse Relaxation of Quadrupolar Nuclei Measured by Multiple Quantum Filtered NMR

    NASA Astrophysics Data System (ADS)

    Eliav, U.; Kushnir, T.; Knubovets, T.; Itzchak, Y.; Navon, G.

    1997-09-01

    The effects of magnetic fieldsB0andB1inhomogeneities on techniques which are commonly used for the measurements of triple-quantum-filtered (TQF) NMR spectroscopy of23Na in biological tissues are analyzed. The results of measurements by pulse sequences with and without refocusing ofB0inhomogeneities are compared. It is shown that without refocusing the errors in the measurement of the transverse relaxation times by TQF NMR spectroscopy may be as large as 100%, and thus, refocusing of magnetic field inhomogeneity is mandatory. Theoretical calculations demonstrate that without refocusingB0inhomogeneities the spectral width and phase depend on the interpulse time intervals, thus, leading to errors in the measured relaxation times. It is shown that pulse sequences that were used for the refocusing of the magnetic field (B0) inhomogeneity also reduce the sensitivity of the experimental results to radiofrequency (B1) magnetic field inhomogeneity.

  20. Understanding Earth's Albedo Effect

    ERIC Educational Resources Information Center

    Fidler, Chuck

    2012-01-01

    Earth and space science in the middle school classroom are composed of intricately intertwined sets of conceptual systems (AAAS 1993; NRC 1996). Some systems of study, such as the water and rock cycles, are quite explicit and often found as stand-alone middle school science units. Other phenomena are not so apparent, yet they play an extremely…

  1. General quadrupolar statistical anisotropy: Planck limits

    NASA Astrophysics Data System (ADS)

    Ramazanov, S.; Rubtsov, G.; Thorsrud, M.; Urban, F. R.

    2017-03-01

    Several early Universe scenarios predict a direction-dependent spectrum of primordial curvature perturbations. This translates into the violation of the statistical isotropy of cosmic microwave background radiation. Previous searches for statistical anisotropy mainly focussed on a quadrupolar direction-dependence characterised by a single multipole vector and an overall amplitude g*. Generically, however, the quadrupole has a more complicated geometry described by two multipole vectors and g*. This is the subject of the present work. In particular, we limit the amplitude g* for different shapes of the quadrupole by making use of Planck 2015 maps. We also constrain certain inflationary scenarios which predict this kind of more general quadrupolar statistical anisotropy.

  2. High-resolution solid-state NMR of quadrupolar nuclei

    PubMed Central

    Meadows, Michael D.; Smith, Karen A.; Kinsey, Robert A.; Rothgeb, T. Michael; Skarjune, Robert P.; Oldfield, Eric

    1982-01-01

    We report the observation of high-resolution solid-state NMR spectra of 23Na (I = [unk]), 27Al (I = [unk]) and 51V (I = [unk]) in various inorganic systems. We show that, contrary to popular belief, relatively high-resolution (≈10 ppm linewidth) spectra may be obtained from quadrupolar systems, in which electric quadrupole coupling constants (e2qQ/h) are in the range ≈1-5 MHz, by means of observation of the (½, -½) spin transition. The (½, -½) transition for all nonintegral spin quadrupolar nuclei (I = [unk], [unk], [unk], or [unk]) is only normally broadened by dipolar, chemical shift (or Knight shift) anisotropy or second-order quadrupolar effects, all of which are to a greater or lesser extent averaged under fast magic-angle sample rotation. In the case of 23Na and 27Al, high-resolution spectra of 23NaNO3 (e2qQ/h ≈300 kHz) and α-27Al2O3 (e2qQ/h ≈2-3 MHz) are presented; in the case of 51V2O5 (e2qQ/h ≈800 kHz), rotational echo decays are observed due to the presence of a ≈103-ppm chemical shift anisotropy. The observation of high-resolution solid-state spectra of systems having spins I = [unk], [unk], and [unk] in asymmetric environments opens up the possibility of examining about two out of three nuclei by solid-state NMR that were previously thought of as “inaccessible” due to the presence of large (a few megahertz) quadrupole coupling constants. Preliminary results for an I = [unk] system, 93Nb, having e2qQ/h ≈19.5 MHz, are also reported. PMID:16593165

  3. Resonant Auger for the detection of quadrupolar transitions

    SciTech Connect

    Danger, J.; Le Fevre, P.; Chandesris, D.; Magnan, H.; Jupille, J.; Bourgeois, S.; Eickhoff, T.; Drube, W.

    2003-01-24

    Quadrupolar transitions can play an important role in X-ray absorption spectroscopy, especially when it is used for magnetic measurements, like in X-ray Magnetic Circular Dichroism or Resonant Magnetic Scattering. We show here that resonantly excited Ti KL2,3L2,3 Auger spectra of TiO2 (110) carry a clear signature of quadrupolar transitions from the 1s to localized eg and t2g d-like states. The quadrupolar nature of the observed additional spectator lines are clearly demonstrated by their angular dependence, and their intensity is used to locate and quantify the quadrupolar transitions in the absorption spectrum.

  4. Theoretical study of homonuclear J coupling between quadrupolar spins: single-crystal, DOR, and J-resolved NMR.

    PubMed

    Perras, Frédéric A; Bryce, David L

    2014-05-01

    The theory describing homonuclear indirect nuclear spin-spin coupling (J) interactions between pairs of quadrupolar nuclei is outlined and supported by numerical calculations. The expected first-order multiplets for pairs of magnetically equivalent (A2), chemically equivalent (AA'), and non-equivalent (AX) quadrupolar nuclei are given. The various spectral changeovers from one first-order multiplet to another are investigated with numerical simulations using the SIMPSON program and the various thresholds defining each situation are given. The effects of chemical equivalence, as well as quadrupolar coupling, chemical shift differences, and dipolar coupling on double-rotation (DOR) and J-resolved NMR experiments for measuring homonuclear J coupling constants are investigated. The simulated J coupling multiplets under DOR conditions largely resemble the ideal multiplets predicted for single crystals, and a characteristic multiplet is expected for each of the A2, AA', and AX cases. The simulations demonstrate that it should be straightforward to distinguish between magnetic inequivalence and equivalence using J-resolved NMR, as was speculated previously. Additionally, it is shown that the second-order quadrupolar-dipolar cross-term does not affect the splittings in J-resolved experiments. Overall, the homonuclear J-resolved experiment for half-integer quadrupolar nuclei is demonstrated to be robust with respect to the effects of first- and second-order quadrupolar coupling, dipolar coupling, and chemical shift differences.

  5. Dynamic-angle spinning and double rotation of quadrupolar nuclei

    SciTech Connect

    Mueller, K.T. California Univ., Berkeley, CA . Dept. of Chemistry)

    1991-07-01

    Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-{1/2} nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids.

  6. On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water

    NASA Astrophysics Data System (ADS)

    Carof, Antoine; Salanne, Mathieu; Charpentier, Thibault; Rotenberg, Benjamin

    2015-11-01

    Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as 7Li+, 23Na+, 25Mg2+, 35Cl-, 39K+, or 133Cs+. Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion.

  7. On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water.

    PubMed

    Carof, Antoine; Salanne, Mathieu; Charpentier, Thibault; Rotenberg, Benjamin

    2015-11-21

    Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as (7)Li(+), (23)Na(+), (25)Mg(2+), (35)Cl(-), (39)K(+), or (133)Cs(+). Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion.

  8. Gravitational quadrupolar coupling and center of gravity: application for Drag-Free Satellites

    NASA Astrophysics Data System (ADS)

    Guilherme, M. S.; Theil, S.

    The motivation of this work is the refinement of modelling of a Drag-Free Satellite DFS for improvement of the disturbance reduction system a so called Drag-Free Control DFC and for the improvement of the data analysis Drag-Free Satellites are missions on fundamental physics as well as geodesy They measure accelerations on a very small scale Especially for the satellites planned for fundamental physics the level of acceleration to be measured is in the range of 10e-15 to 10e-18 m s 2 Because of that any disturbance and misalignment should be modelled Due to the gravity gradient for most extended bodies the center of gravity deviates from the center of mass This results in a gravity gradient torque on satellites as well as on the test masses which depends on the attitude with respect to the gravity gradient In addition the gravity force is also attitude dependent This paper describes this gravity gradient force acting on arbitrary bodies for higher orders of the inertia moments It shows also the influence of the quadrupolar gravitational coupling to the Earth gravity field An equation is developed that determines the center of gravity in the body frame It provides a visualization of the deviation of the center of gravity from the center of mass In order to evaluate the significance of this effects values are computed for several fundamental physicals missions e g GRAVITY PROBE B and STEP

  9. Detecting supernovae neutrino with Earth matter effect

    NASA Astrophysics Data System (ADS)

    Liao, Wei

    2016-12-01

    We study Earth matter effect in oscillations of supernovae neutrinos. We show that detecting Earth matter effect gives an independent measurement of spectra of supernovae neutrinos, i.e., the flavor difference of the spectra of supernovae neutrinos. We study the effect of energy resolution and angular resolution of a final electron or positron on detecting the signal of Earth matter effect. We show that varying the widths of energy bins in analysis can change the signal strength of Earth matter effect and the statistical fluctuation. A reasonable choice of energy bins can both suppress the statistical fluctuation and make a good signal strength relative to the statistical fluctuation. Neutrino detectors with good energy resolution and good angular resolution are therefore preferred so that there is more freedom to vary energy bins and to optimize the signal of Earth matter effect in analyzing events of supernovae neutrinos.

  10. Geophysical Effects of the Earth's Monthly Motion

    NASA Astrophysics Data System (ADS)

    Sidorenkov, N. S.; Zhigailo, T. S.

    The generation of a lunar tidal force is a major geophysical effect of the Earth's monthly motion.It is shown that synoptic processes vary simultaneously with tidal oscillations of the Earth's rotation rate and weather exhibits changes near their extremes, i.e., when the Earth is in certain positions on its monthly orbit.It is found that the quasi-biennial oscillation of the wind direction in the equatorial stratosphere is a combined oscillation caused by three periodic processes experienced by the atmosphere: (a) lunisolar tides, (b) the precession of the orbit of the Earth's monthly rotation around the barycenter of the Earth-Moon system, and (c) the motion of the perigee of this orbit.Interference of the 1.20-year Chandler wobble with sidereal, anomalistic, and synodic lunar oscillations gives rise to beats, i.e., to slow periodic variations in the wobble amplitude with periods of 32 to 51 years.

  11. High-Resolution NMR of Quadrupolar Nuclei in the Solid State

    SciTech Connect

    Gann, Sheryl Lee

    1995-11-01

    This dissertation describes recent developments in solid state nuclear magnetic resonance (NMR), for the most part involving the use of dynamic-angle spinning (DAS) NMR to study quadrupolar nuclei. Chapter 1 introduces some of the basic concepts and theory that will be referred to in later chapters, such as the density operator, product operators, rotations, coherence transfer pathways, phase cycling, and the various nuclear spin interactions, including the quadrupolar interaction. Chapter 2 describes the theory behind motional averaging experiments, including DAS, which is a technique where a sample is spun sequentially about two axis oriented at different angles with respect to the external magnetic field such that the chemical shift and quadrupolar anisotropy are averaged to zero. Work done on various rubidium-87 salts is presented as a demonstration of DAS. Chapter 3 explains how to remove sidebands from DAS and magic-angle spinning (MAS) experiments, which result from the time-dependence of the Hamiltonian under sample spinning conditions, using rotor-synchronized π-pulses. Data from these experiments, known as DAH-180 and MAH-180, respectively, are presented for both rubidium and lead salts. In addition, the applicability of this technique to double rotation (DOR) experiments is discussed. Chapter 4 concerns the addition of cross-polarization to DAS (CPDAS). The theory behind spin locking and cross polarizing quadrupolar nuclei is explained and a method of avoiding the resulting problems by performing cross polarization at 0° $\\parallel$ with respect to the magnetic field is presented. Experimental results are shown for a sodium-23 compound, sodium pyruvate, and for oxygen-17 labeled L-akmine. In Chapter 5, a method for broadening the Hartmann-Hahn matching condition under MAS, called variable effective field cross-polarization (VEFCP), is presented, along with experimental work on adamantane and polycarbonate.

  12. Solution deuterium NMR quadrupolar relaxation study of heme mobility in myoglobin

    SciTech Connect

    Johnson, R.D.; La Mar, G.N.; Smith, K.M.; Parish, D.W.; Langry, K.C. )

    1989-01-18

    NMR spectroscopy has been used to monitor the quadrupolar relaxation and motional dynamics of {sup 2}H selectively incorporated into skeletal and side chain positions of the heme in sperm whale myoglobin. The hyperfine shifts of the heme resonances in paramagnetic states of myoglobin allow resolution of the signals of interest, and paramagnetic contributions to the observed line widths are shown to be insignificant. The {sup 2}H line widths for the skeletal positions of deuterohemin-reconstituted myoglobin yield a correlation time identical with that of overall protein tumbling (9 ns at 30{degree}C) and hence reflect an immobile heme group. The {sup 2}H NMR line widths of heme methyl groups exhibit motional narrowing indicative of very rapid internal rotation. Hence the methyl rotation is effectively decoupled from the overall protein tumbling, and the residual quadrupolar line width can be used directly to determine the protein tumbling rate. The {sup 2}H NMR lines from heme vinyl groups were found narrower than those from the heme skeleton. However, the range of quadrupolar coupling constants for sp{sup 2} hybridized C-{sup 2}H bonds does not permit an unequivocal interpretation in terms of mobility. 48 refs., 4 figs.

  13. Quantitative structure parameters from the NMR spectroscopy of quadrupolar nuclei

    SciTech Connect

    Perras, Frederic A.

    2015-12-15

    Here, nuclear magnetic resonance (NMR) spectroscopy is one of the most important characterization tools in chemistry, however, 3/4 of the NMR active nuclei are underutilized due to their quadrupolar nature. This short review centers on the development of methods that use solid-state NMR of quadrupolar nuclei for obtaining quantitative structural information. Namely, techniques using dipolar recoupling as well as the resolution afforded by double-rotation are presented for the measurement of spin–spin coupling between quadrupoles, enabling the measurement of internuclear distances and connectivities.

  14. On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water

    SciTech Connect

    Carof, Antoine; Salanne, Mathieu; Rotenberg, Benjamin; Charpentier, Thibault

    2015-11-21

    Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as {sup 7}Li{sup +}, {sup 23}Na{sup +}, {sup 25}Mg{sup 2+}, {sup 35}Cl{sup −}, {sup 39}K{sup +}, or {sup 133}Cs{sup +}. Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion.

  15. Quadrupolar, Triple [Delta]-Function Potential in One Dimension

    ERIC Educational Resources Information Center

    Patil, S. H.

    2009-01-01

    The energy and parity eigenstates for quadrupolar, triple [delta]-function potential are analysed. Using the analytical solutions in specific domains, simple expressions are obtained for even- and odd-parity bound-state energies. The Heisenberg uncertainty product is observed to have a minimum for a specific strength of the potential. The…

  16. 127I NMR study of quadrupolar echoes in KI

    NASA Astrophysics Data System (ADS)

    Lee, Nelson; Sanctuary, B. C.; Halstead, T. K.

    Potassium iodide (K 121I), like KBr and many other alkali halide solids, has cubic symmetry. Distortion of this cubic symmetry in single crystals of KI creates electric field gradients of sufficient strength for the quadrupolar interactions to dominate the dynamics of the system. Simple one-, two-, and three-pulse sequences applied to such crystals permit the observation, in the time domain, of the solid- or quadrupolar-echo phenomenon for spin I = {5}/{2}( 127I) . Using the multipole approach to interpret the experimental responses of three-pulse sequences, the characteristic relaxation behavior of the first-, second-, third-, and fifth-rank zero- and multiquantum polarizations are determined. The experimental determination of distinct relaxation times for the higher rank polarizations in both KI and KBr ( I = {3}/{2}) lends credibility to the concept of the multipoles as physical quantities.

  17. Two-dimensional nuclear magnetic resonance of quadrupolar systems

    SciTech Connect

    Wang, Shuanhu

    1997-09-01

    This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combining the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.

  18. Population transfer HMQC for half-integer quadrupolar nuclei

    SciTech Connect

    Wang, Qiang; Xu, Jun; Feng, Ningdong; Deng, Feng E-mail: jean-paul.amoureux@univ-lille1.fr; Li, Yixuan; Trébosc, Julien; Lafon, Olivier; Hu, Bingwen; Chen, Qun; Amoureux, Jean-Paul E-mail: jean-paul.amoureux@univ-lille1.fr

    2015-03-07

    This work presents a detailed analysis of a recently proposed nuclear magnetic resonance method [Wang et al., Chem. Commun. 49(59), 6653-6655 (2013)] for accelerating heteronuclear coherence transfers involving half-integer spin quadrupolar nuclei by manipulating their satellite transitions. This method, called Population Transfer Heteronuclear Multiple Quantum Correlation (PT-HMQC), is investigated in details by combining theoretical analyses, numerical simulations, and experimental investigations. We find that compared to instant inversion or instant saturation, continuous saturation is the most practical strategy to accelerate coherence transfers on half-integer quadrupolar nuclei. We further demonstrate that this strategy is efficient to enhance the sensitivity of J-mediated heteronuclear correlation experiments between two half-integer quadrupolar isotopes (e.g., {sup 27}Al-{sup 17}O). In this case, the build-up is strongly affected by relaxation for small T{sub 2}′ and J coupling values, and shortening the mixing time makes a huge signal enhancement. Moreover, this concept of population transfer can also be applied to dipolar-mediated HMQC experiments. Indeed, on the AlPO{sub 4}-14 sample, one still observes experimentally a 2-fold shortening of the optimum mixing time albeit with no significant signal gain in the {sup 31}P-({sup 27}Al) experiments.

  19. Earth Sphericity Effects on Subduction Morphology

    NASA Astrophysics Data System (ADS)

    Morra, G.; Chatelain, P.; Tackley, P.; Koumoutsakos, P.

    2007-12-01

    We present here the first application in Geodynamics of a Multipole accelerated Boundary Element Method (FMM- BEM) for Stokes Flow. The approach offers the advantage of a reduced number of computational elements and linear scaling with the problem size. We show that this numerical mehod can be fruitfully applied to the simulation of several geodynamic systems at the planetary scale in spheical coordinates and we suggest a general appraoch for modeling combined mantle convection and plate tectonics. The potentialities of the approach are shown investigating the effect played by Earth sphericity on the subduction of a very wide oceanic lithosphere , comparing the morphology of the subducted lithosphere in a spherical and in flat setting. The results show a striking difference between the two models: while the slab on a "flat Earth" shows slight undulation, the same subducting plate on a spherical Earth-like setting presents a distinct folding below the trench far from the edges, with wavelength of (1000km-2000km) as Pacific trenches.

  20. Effect of rotating earth for AOTV analysis

    NASA Astrophysics Data System (ADS)

    Ikawa, H.

    The Aeroassisted Orbit Transfer Vehicle (AOTV) operates in the endo/exoatmosphere. Exoatmospheric flight phase is dictated only by the inertial properties. In endoatmospheric flight phase, the trajectory is also shaped by the inertial velocity. However, the aerodynamic maneuver that causes the trajectory perturbation is controlled by the relative velocity. For example, along the equatorial flight path: (1) the velocity difference between the inertial and the relative reference frames represents 5 to 7 percent of the entry velocity; (2) the dynamic pressure difference becomes 10 to 14 percent, which is significant in evaluating the proper atmospheric flight maneuver; (3) in consequence, exit errors that are induced at the edge of the sensible atmosphere produce significant deviation in the final orbit transfer. The possible errors affecting AOTV analyses conducted by neglecting the earth's rotation are discussed. The control laws using the shallow glide path ascent and the constant altitude glide trajectories in the atmosphere, with the required pull-up maneuver, are also demonstrated. Conclusions are: (1) AOTV analyses using the stationary earth assumption tend to underpredict the final LEO altitude and to overpredict the orbital inclination change, and (2) effects of the rotating earth cannot be ignored for realistic AOTV simulations.

  1. On the relationship between quadrupolar magnetic field and collisionless reconnection

    SciTech Connect

    Smets, R. Belmont, G.; Aunai, N.; Boniface, C.

    2014-06-15

    Using hybrid simulations, we investigate the onset of fast reconnection between two cylindrical magnetic shells initially close to each other. This initial state mimics the plasma structure in High Energy Density Plasmas induced by a laser-target interaction and the associated self-generated magnetic field. We clearly observe that the classical quadrupolar structure of the out-of-plane magnetic field appears prior to the reconnection onset. Furthermore, a parametric study reveals that, with a non-coplanar initial magnetic topology, the reconnection onset is delayed and possibly suppressed. The relation between the out-of-plane magnetic field and the out-of-plane electric field is discussed.

  2. Quinoline-Derived Two-Photon Sensitive Quadrupolar Probes.

    PubMed

    Tran, Christine; Berqouch, Nawel; Dhimane, Hamid; Clermont, Guillaume; Blanchard-Desce, Mireille; Ogden, David; Dalko, Peter I

    2017-02-03

    Quadrupolar probes derived from 8-dimethylamino-quinoline (8-DMAQ) having a pegylated fluorene core were prepared and studied under "one-photon" (λ=365 nm) and "two-photon" (TP) (λ=730 nm) irradiation conditions. Compound 1 a was identified as the most efficient probe by UV activation that showed sequential release of acetic acid as a model. Although the probe showed high two-photon absorption it stayed inert under femtosecond irradiation conditions. Fast and selective photolysis was observed, however, by using picosecond irradiation conditions with a remarkably high TP uncaging cross-section (δu =2.3 GM).

  3. High-field QCPMG NMR of large quadrupolar patterns using resistive magnets.

    PubMed

    Hung, Ivan; Shetty, Kiran; Ellis, Paul D; Brey, William W; Gan, Zhehong

    2009-12-01

    Spectroscopy in a high magnetic field reduces second-order quadrupolar shift while increasing chemical shift. It changes the scale between quadrupolar and chemical shift of half-integer quadrupolar spins. The application of QCPMG multiple echo for acquiring large quadrupolar pattern under the high magnetic field of a 25 T resistive magnet is presented for acquiring large quadrupolar patterns. It shows that temporal field fluctuations and spatial homogeneity of the Keck magnet at the NHMFL contribute about +/- 20 ppm in line broadening. NMR patterns which have breadths of hundreds to thousands of kilohertz can be efficiently recorded using a combination of QCPMG and magnetic field stepping with negligible hindrance from the inhomogeneity and field fluctuations of powered magnets.

  4. Quantum mechanical identification of quadrupolar plasmonic excited states in silver nanorods

    SciTech Connect

    Gieseking, Rebecca L.; Ratner, Mark A.; Schatz, George C.

    2016-10-27

    Quadrupolar plasmonic modes in noble metal nanoparticles have gained interest in recent years for various sensing applications. Although quantum mechanical studies have shown that dipolar plasmons can be modeled in terms of excited states where several to many excitations contribute coherently to the transition dipole moment, new approaches are needed to identify the quadrupolar plasmonic states. We show that quadrupolar states in Ag nanorods can be identified using the semiempirical INDO/SCI approach by examining the quadrupole moment of the transition density. The main longitudinal quadrupolar states occur at higher energies than the longitudinal dipolar states, in agreement with previous classical electrodynamics results, and have collective plasmonic character when the nanorods are sufficiently long. In conclusion, the ability to identify these states will make it possible to evaluate the differences between dipolar and quadrupolar plasmons that are relevant for sensing applications.

  5. Quantum mechanical identification of quadrupolar plasmonic excited states in silver nanorods

    DOE PAGES

    Gieseking, Rebecca L.; Ratner, Mark A.; Schatz, George C.

    2016-10-27

    Quadrupolar plasmonic modes in noble metal nanoparticles have gained interest in recent years for various sensing applications. Although quantum mechanical studies have shown that dipolar plasmons can be modeled in terms of excited states where several to many excitations contribute coherently to the transition dipole moment, new approaches are needed to identify the quadrupolar plasmonic states. We show that quadrupolar states in Ag nanorods can be identified using the semiempirical INDO/SCI approach by examining the quadrupole moment of the transition density. The main longitudinal quadrupolar states occur at higher energies than the longitudinal dipolar states, in agreement with previous classicalmore » electrodynamics results, and have collective plasmonic character when the nanorods are sufficiently long. In conclusion, the ability to identify these states will make it possible to evaluate the differences between dipolar and quadrupolar plasmons that are relevant for sensing applications.« less

  6. QUEST-QUadrupolar Exact SofTware: a fast graphical program for the exact simulation of NMR and NQR spectra for quadrupolar nuclei.

    PubMed

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

    2012-01-01

    We present a new program for the exact simulation of solid-state NMR spectra of quadrupolar nuclei in stationary powdered samples which employs diagonalization of the combined Zeeman-quadrupolar Hamiltonian. The program, which we call QUEST (QUadrupolar Exact SofTware), can simulate NMR spectra over the full regime of Larmor and quadrupolar frequency ratios, which encompasses scenarios ranging from high-field NMR to nuclear quadrupole resonance (NQR, where the Larmor frequency is zero) and does not make use of approximations when treating the quadrupolar interaction. With the use of the fast powder averaging scheme of Alderman, Solum, and Grant, exact NMR spectral simulations are only marginally slower than the second-order perturbation theory counterpart. The program, which uses a graphical user interface, also incorporates chemical shift anisotropy and non-coincident chemical shift and quadrupolar tensor frames. The program is validated against newly-acquired experimental data through several examples including: the low-field (79/81)Br NMR spectra of CaBr(2), the (14)N overtone NMR spectrum of glycine, the (187)Re NQR spectra of Re(2)(CO)(10), and lastly the (127)I overtone NQR spectrum of SrI(2), which, to the best of our knowledge, represents the first direct acquisition of an overtone NQR spectrum for a powdered sample.

  7. Structure and orientational ordering in a fluid of elongated quadrupolar molecules

    NASA Astrophysics Data System (ADS)

    Singh, Ram Chandra

    2013-01-01

    A second-order density-functional theory is used to study the effect of quadrupolar interactions on the isotropic-nematic transition in a system of fluids of elongated molecules interacting via the Gay-Berne potential. The direct pair-correlation functions of the coexisting isotropic fluid that enter in the theory as input information are obtained by solving the Ornstein-Zernike equation using the Percus-Yevick integral equation theory in the (reduced) temperature range of 1.6≤T∗≤3.0 for different densities, temperatures and quadrupole moments. Using the harmonic coefficients of the direct pair-correlation functions, isotropic-nematic phase coexistence and thermodynamic parameters have been calculated. The theoretical results have been compared with the available computer simulation results.

  8. Quadrupolar relaxation of hyperpolarized krypton-83 as a probe for surfaces.

    PubMed

    Stupic, Karl F; Cleveland, Zackary I; Pavlovskaya, Galina E; Meersmann, Thomas

    2006-02-01

    This work reports the first systematic study of relaxation experienced by the hyperpolarized (hp) noble gas isotope (83)Kr (I=9/2) in contact with surfaces. The spin-lattice relaxation of (83)Kr is found to depend strongly on the chemical composition of the surfaces in the vicinity of the gas. This effect is caused by quadrupolar interactions during brief periods of surface adsorption that are the dominating source of longitudinal spin relaxation in the (83)Kr atoms. Simple model systems of closest packed glass beads with uniform but variable bead sizes are used for the relaxation measurements. The observed relaxation rates depend strongly on the chemical treatment of the glass surfaces and on the surface to volume ratio. Hp (83)Kr NMR relaxation measurements of porous polymers with pore sizes of 70-250 microm demonstrate the potential use of this new technique for material sciences applications.

  9. Distinguishing magnetic vs. quadrupolar relaxation in b-NMR using 8Li and 9Li

    NASA Astrophysics Data System (ADS)

    Chatzichristos, A.; McFadden, R. M. L.; Karner, V. L.; Cortie, D. L.; Fang, A.; Levy, C. D. P.; Macfarlane, W. A.; Morris, G. D.; Pearson, M. R.; Salman, Z.; Kiefl, R. F.

    2016-09-01

    Beta-detected NMR is a powerful technique in condensed matter physics. It uses the parity violation of beta decay to detect the NMR signal from a beam of highly polarized radionuclides implanted in a sample material. Spin-lattice relaxation (SLR) is studied by monitoring the rate with which the asymmetry between the beta counts in two opposing detectors is lost. Unlike classical NMR, b-NMR can study thin films and near-surface effects. The most common b-NMR isotope at TRIUMF is 8Li, which has a quadrupole moment, thus it is sensitive to both magnetic fields and electric field gradients. A challenge with 8Li b-NMR is identifying the predominant mechanism of SLR in a given sample. It is possible to distinguish between SLR mechanisms by varying the probe isotope. For two isotopes with different nuclear moments, the ratio of SLR rates should be different in the limits of either pure magnetic or quadrupolar relaxation. This method has been used in classical NMR and we report its first application to b-NMR. We measured the SLR rates for 8Li and 8Li in Pt foil and SrTiO3. Pt is a test case for pure magnetic relaxation. SrTiO3 is a non-magnetic insulator, but the source of its relaxation is not well understood. Here we show that its relaxation is mainly quadrupolar. We thank TRIUMF's CMMS for their technical support. This work was supported by: NSERC Discovery Grants to R.F.K. and W.A.M.; and IsoSiM fellowships to A.C. and R.M.L.M.

  10. Effects of spraying rare earths on contents of rare Earth elements and effective components in tea.

    PubMed

    Wang, Dongfeng; Wang, Changhong; Ye, Sheng; Qi, Hongtao; Zhao, Guiwen

    2003-11-05

    Rare earth (RE) fertilizer is widely applied in China to increase the yield and the quality of crops including tea. However, the effects of spraying RE fertilizer on the contents of rare earth elements (REE) and effective components in tea are unknown. The results from basin and field experiments show that the values of the REE concentrations in new shoots of tea plants and the concentration of REE in the soil (REE/REEs) either from control basins or from treatment basins were smaller than those in other parts of tea plant and similar between control and treatment. The longer the interval between spraying RE fertilizer and picking the shoots of tea plants, the less the effects from spraying. About 80% summation operator REE (the sum of the concentrations of 15 REE) in tea, whether it came from spraying or not, was insoluble in the infusion. About 10% the soluble REE of summation operator REE in tea infusion was bound to polysaccharide, and the amount of REE bound polysaccharide decreased over time. At least a 25 day safety interval is needed between spraying and picking if the microelement fertilizer is used, in order to enhance tea output and to ensure tea safety.

  11. Effects of the tidal mass redistribution on the Earth rotation

    NASA Astrophysics Data System (ADS)

    Baenas, T.; Ferrándiz, J.; Escapa, A.; Getino, J.

    2015-08-01

    The effects of the tidal mass redistributions on the Earth precession and nutations are revisited, under various hypothesis on the elastic response of the Earth and using the Hamiltonian approach. New non-negligible secular and periodic contributions have been found.

  12. Studies of heteronuclear dipolar interactions between spin-1/2 and quadrupolar nuclei by using REDOR during multiple quantum evolution

    NASA Astrophysics Data System (ADS)

    Pruski, M.; Bailly, A.; Lang, D. P.; Amoureux, J.-P.; Fernandez, C.

    1999-06-01

    A new technique for measurements of dipolar interactions in rotating solids is presented that combines the capabilities of multiple quantum magic angle spinning (MQMAS) with the rotational echo double resonance (REDOR). It employs the dipolar recoupling between spin-1/2 ( I) and quadrupolar ( S) nuclei by applying a series of π pulses to the I spins. In contrast to the previously reported MQ-REDOR method, the recoupling sequence is applied during the triple quantum, rather than single quantum evolution. As the dipolar effect is enhanced by the MQ coherence order, this new technique exhibits improved sensitivity toward weak dipolar interactions.

  13. DFT-D study of 14N nuclear quadrupolar interactions in tetra-n-alkyl ammonium halide crystals.

    PubMed

    Dib, Eddy; Alonso, Bruno; Mineva, Tzonka

    2014-05-15

    The density functional theory-based method with periodic boundary conditions and addition of a pair-wised empirical correction for the London dispersion energy (DFT-D) was used to study the NMR quadrupolar interaction (coupling constant CQ and asymmetry parameter ηQ) of (14)N nuclei in a homologous series of tetra-n-alkylammonium halides (C(x)H(2x+1))4N(+)X(-) (x = 1-4), (X = Br, I). These (14)N quadrupolar properties are particularly challenging for the DFT-D computations because of their very high sensitivity to tiny geometrical changes, being negligible for other spectral property calculations as, for example, NMR (14)N chemical shift. In addition, the polarization effect of the halide anions in the considered crystal mesophases combines with interactions of van der Waals type between cations and anions. Comparing experimental and theoretical results, the performance of PBE-D functional is preferred over that of B3LYP-D. The results demonstrated a good transferability of the empirical parameters in the London dispersion formula for crystals with two or more carbons per alkyl group in the cations, whereas the empirical corrections in the tetramethylammonium halides appeared to be inappropriate for the quadrupolar interaction calculation. This is attributed to the enhanced cation-anion attraction, which causes a strong polarization at the nitrogen site. Our results demonstrated that the (14)N CQ and ηQ are predominantly affected by the molecular structures of the cations, adapted to the symmetry of the anion arrangements. The long-range polarization effect of the surrounding anions at the target nitrogen site becomes more important for cells with lower spatial symmetry.

  14. Asymmetric effects on Earth's polar motion

    NASA Astrophysics Data System (ADS)

    Bizouard, Christian; Zotov, Leonid

    2013-06-01

    Differential equations ruling the Earth's polar motion are slightly asymmetric with respect to the pole coordinates. This is not only associated with the lack of axial symmetry around the Earth figure axis (triaxiality) but also with the longitude dependency of the pole tide (the main contribution). We propose a consistent handling of both asymmetric contributions, formulating a unique equation in the complex equatorial plane, of which we derive a general solution. Difference with respect to the usual symmetric solution is discussed and found significant in light of the present accuracy of the observed pole coordinates. For the same geophysical excitation, the prograde Chandler wobble is accompanied by a retrograde component up to 2 milliarcseconds (mas), transforming it in a slight elliptic motion. The asymmetric contribution is relatively larger in the geodetic excitation function, for Chandler wobble excitation mixes prograde and retrograde components of comparable level (1 mas).

  15. High radio-frequency field strength nutation NMR of quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Franssen, W. M. J.; Rezus, Y. L. A.; Kentgens, A. P. M.

    2016-12-01

    Owing to the introduction of microcoils, high RF field strength nutation NMR is a viable candidate for the study of quadrupolar nuclei with strong quadrupolar couplings, not accessible using contemporary NMR techniques. We show powder 23 Na nutation spectra on sodium nitrite for RF field strengths of up to 1170 kHz, that conform to theoretical predictions. For lanthanum fluoride powder, 139 La nutation spectra taken at elevated RF field amplitudes show clear discrepancies when compared to the theory. These errors are shown to be mainly caused by pulse transients at the end of the pulse, which proved to be detrimental to the shape of the nutation spectra. Using a nutation pulse which ends in a sudden frequency jump, we show that these errors can be reduced, and nutation spectra that conform to theory can be readily acquired. This enables nutation NMR for the study of quadrupolar nuclei with a strong quadrupolar coupling, bridging the gap between NMR, which can only analyse nuclei with a weak to medium quadrupolar coupling, and NQR, were extensive searching for the right quadrupolar frequency is the limiting factor.

  16. Earth matter effects in detection of supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Guo, X.-H.; Young, Bing-Lin

    2006-05-01

    We calculated the matter effect, including both the Earth and supernova, on the detection of neutrinos from type II supernovae at the proposed Daya Bay reactor neutrino experiment. It is found that apart from the dependence on the flip probability PH inside the supernova and the mass hierarchy of neutrinos, the amount of the Earth matter effect depends on the direction of the incoming supernova neutrinos, and reaches the biggest value when the incident angle of neutrinos is around 93°. In the reaction channel ν¯e+p→e++n the Earth matter effect can be as big as about 12%. For other detection processes the amount of the Earth matter effect is a few per cent.

  17. Earth matter effects in detection of supernova neutrinos

    SciTech Connect

    Guo, X.-H.; Young Binglin

    2006-05-01

    We calculated the matter effect, including both the Earth and supernova, on the detection of neutrinos from type II supernovae at the proposed Daya Bay reactor neutrino experiment. It is found that apart from the dependence on the flip probability P{sub H} inside the supernova and the mass hierarchy of neutrinos, the amount of the Earth matter effect depends on the direction of the incoming supernova neutrinos, and reaches the biggest value when the incident angle of neutrinos is around 93 deg. In the reaction channel {nu}{sub e}+p{yields}e{sup +}+n the Earth matter effect can be as big as about 12%. For other detection processes the amount of the Earth matter effect is a few per cent.

  18. DFT calculations of quadrupolar solid-state NMR properties: Some examples in solid-state inorganic chemistry.

    PubMed

    Cuny, Jerome; Messaoudi, Sabri; Alonzo, Veronique; Furet, Eric; Halet, Jean-François; Le Fur, Eric; Ashbrook, Sharon E; Pickard, Chris J; Gautier, Regis; Le Polles, Laurent

    2008-10-01

    This article presents results of first-principles calculations of quadrupolar parameters measured by solid-state nuclear magnetic measurement (NMR) spectroscopy. Different computational methods based on density functional theory were used to calculate the quadrupolar parameters. Through a series of illustrations from different areas of solid state inorganic chemistry, it is shown how quadrupolar solid-state NMR properties can be tackled by a theoretical approach and can yield structural information.

  19. Effects of Earth Encounters on the Rotational Properties of Near-Earth Objects

    NASA Astrophysics Data System (ADS)

    Chit Siu, Ho; Keane, James T.; Moskovitz, Nicholas; Binzel, Richard P.

    2015-11-01

    The effects of Earth encounters on the physical properties of near-Earth objects (NEOs) have been shown to be significant factors in their evolution. Previous studies have examined the effects of these encounters on reflectance spectra, and effects such as spin state and shape changes have been studied for specific asteroids and through simulation. In this study, archive data from previous NEO surveys were used to investigate rotational frequencies as a function of minimum orbit intersection distance (MOID), which we use as a proxy for Earth encounter likelihood.When comparing objects of similar sizes, we find a highly significant difference in the dispersion of rotational frequency (p < 0.01; significant at a >99% confidence level) between NEO populations that were likely to have had an Earth encounter and those that are less likely to have had such an encounter. The encounter/non-encounter distinction is found at a dividing MOID value of 1 lunar distance (LD). These results were robust to changes in the size of the moving average window, as well as to removal of the smallest objects from the encounter population and the largest objects from the non-encounter population, which would be most strongly affected by a known size/spin period bias where smaller objects tend to have shorter periods. There was no statistically significant difference in the mean rotation rates of encounter and non-encounter objects, however, indicating that encounters cause greater dispersion, but do not preferentially spin objects up or down at a detectable level. Recent modeling work also lends credibility to the idea that NEO interactions with the Earth-Moon system as a whole may be leading to the dispersion difference boundary at 1 LD (Keane et al. 2015, DPS).

  20. Instability of some divalent rare earth ions and photochromic effect

    NASA Astrophysics Data System (ADS)

    Egranov, A. V.; Sizova, T. Yu.; Shendrik, R. Yu.; Smirnova, N. A.

    2016-03-01

    It was shown that the divalent rare earth ions (La, Ce, Gd, Tb, Lu, and Y) in cubic sites in alkaline earth fluorides are unstable with respect to electron autodetachment since its d1(eg) ground state is located in the conduction band which is consistent with the general tendency of these ions in various compounds. The localization of doubly degenerate d1(eg) level in the conduction band creates a configuration instability around the divalent rare earth ion that leading to the formation of anion vacancy in the nearest neighborhood, as was reported in the previous paper [A. Egranov, T. Sizova, Configurational instability at the excited impurity ions in alkaline earth fluorites, J. Phys. Chem. Solids 74 (2013) 530-534]. Thus, the formation of the stable divalent ions as La, Ce, Gd, Tb, Lu, and Y (PC+ centers) in CaF2 and SrF2 crystals during x-ray irradiation occurs via the formation of charged anion vacancies near divalent ions (Re2+va), which lower the ground state of the divalent ion relative to the conductivity band. Photochromic effect occurs under thermally or optically stimulated electron transition from the divalent rare earth ion to the neighboring anion vacancy and reverse under ultraviolet light irradiation. It is shown that the optical absorption of the PC+ centers due to d → d and d → f transitions of the divalent rare-earth ion.

  1. Solid state nuclear magnetic resonance studies of cross polarization from quadrupolar nuclei

    SciTech Connect

    De Paul, Susan M.

    1997-08-01

    The development of solid-state Nuclear Magnetic Resonance (NMR) has, to a large extent, focused on using spin-1/2 nuclei as probes to investigate molecular structure and dynamics. For such nuclei, the technique of cross polarization is well-established as a method for sensitivity enhancement. However, over two-thirds of the nuclei in the periodic table have a spin-quantum number greater than one-half and are known as quadrupolar nuclei. Such nuclei are fundamental constituents of many inorganic materials including minerals, zeolites, glasses, and gels. It is, therefore, of interest to explore the extent to which polarization can be transferred from quadrupolar nuclei. In this dissertation, solid-state NMR experiments involving cross polarization from quadrupolar nuclei to spin-1/2 nuclei under magic-angle spinning (MAS) conditions are investigated in detail.

  2. PRESTO polarization transfer to quadrupolar nuclei: Implications for dynamic nuclear polarization

    DOE PAGES

    Perras, Frederic A.; Kobayashi, Takeshi; Pruski, Marek

    2015-08-04

    In this study, we show both experimentally and numerically on a series of model systems that in experiments involving transfer of magnetization from 1H to the quadrupolar nuclei under magic-angle-spinning (MAS), the PRESTO technique consistently outperforms traditionally used cross polarization (CP), affording more quantitative intensities, improved lineshapes, better overall sensitivity, and straightforward optimization. This advantage derives from the fact that PRESTO circumvents the convoluted and uncooperative spin dynamics during the CP transfer under MAS, by replacing the spin-locking of quadrupolar nuclei with a single central transition selective 90° pulse and using a symmetry-based recoupling sequence in the 1H channel. Thismore » is important in the context of dynamic nuclear polarization (DNP) NMR of quadrupolar nuclei, where the efficient transfer of enhanced 1H polarization is desired to obtain the highest sensitivity.« less

  3. PRESTO polarization transfer to quadrupolar nuclei: Implications for dynamic nuclear polarization

    SciTech Connect

    Perras, Frederic A.; Kobayashi, Takeshi; Pruski, Marek

    2015-08-04

    In this study, we show both experimentally and numerically on a series of model systems that in experiments involving transfer of magnetization from 1H to the quadrupolar nuclei under magic-angle-spinning (MAS), the PRESTO technique consistently outperforms traditionally used cross polarization (CP), affording more quantitative intensities, improved lineshapes, better overall sensitivity, and straightforward optimization. This advantage derives from the fact that PRESTO circumvents the convoluted and uncooperative spin dynamics during the CP transfer under MAS, by replacing the spin-locking of quadrupolar nuclei with a single central transition selective 90° pulse and using a symmetry-based recoupling sequence in the 1H channel. This is important in the context of dynamic nuclear polarization (DNP) NMR of quadrupolar nuclei, where the efficient transfer of enhanced 1H polarization is desired to obtain the highest sensitivity.

  4. Multiple-quantum cross-polarization in MAS NMR of quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Ashbrook, Sharon E.; Brown, Steven P.; Wimperis, Stephen

    1998-05-01

    Using 27Al ( I=5/2) NMR of aluminium acetylacetonate, we show that it is possible to cross-polarize from a spin I=1/2 nucleus ( 1H) directly to the central triple-quantum transition of a half-integer quadrupolar nucleus ( 27Al) in a powdered sample under MAS conditions. The optimum conditions for this multiple-quantum cross-polarization (MQCP) are investigated experimentally and compared with existing theoretical results. The new technique is applied to the recently introduced two-dimensional MQMAS experiment for recording high-resolution NMR spectra of half-integer quadrupolar nuclei.

  5. Propagation Effects in Space/Earth Paths.

    DTIC Science & Technology

    1980-08-01

    staff and other collaborators. H.J.ALBRECHT Editor &COeSsioi or- XTIS GRPA.I TDC TAB LVve ounc ed Justification Di t ribut’i / .li /vfl.,Q4."s Codes...SOLUTIONS by E.Baha and B.S.Agrawal 24 1979-1980 DATA PROCESSING AND RESULTS FROM THE OTS BEACONS BO/B I AND TM , AND RADIOMETRY AT 11.4 AND 35 GHz by...scatterers, neglecting high order scattering 1 4 may be written: a(dB) =[1/(l-w)]10 log [ Tm /( Tm -TA)] where w is the scattering albedo and Tm the effective

  6. The Runaway Greenhouse Effect on Earth and other Planets

    NASA Technical Reports Server (NTRS)

    Rabbette, Maura; Pilewskie, Peter; McKay, Christopher; Young, Robert

    2001-01-01

    Water vapor is an efficient absorber of outgoing longwave infrared radiation on Earth and is the primary greenhouse gas. Since evaporation increases with increasing sea surface temperature, and the increase in water vapor further increases greenhouse warming, there is a positive feedback. The runaway greenhouse effect occurs if this feedback continues unchecked until all the water has left the surface and enters the atmosphere. For Mars and the Earth the runaway greenhouse was halted when water vapor became saturated with respect to ice or liquid water respectively. However, Venus is considered to be an example of a planet where the runaway greenhouse effect did occur, and it has been speculated that if the solar luminosity were to increase above a certain limit, it would also occur on the Earth. Satellite data acquired during the Earth Radiation Budget Experiment (ERBE) under clear sky conditions shows that as the sea surface temperature (SST) increases, the rate of outgoing infrared radiation at the top of the atmosphere also increases, as expected. Over the pacific warm pool where the SST exceeds 300 K the outgoing radiation emitted to space actually decreases with increasing SST, leading to a potentially unstable system. This behavior is a signature of the runaway greenhouse effect on Earth. However, the SST never exceeds 303K, thus the system has a natural cap which stops the runaway. According to Stefan-Boltzmann's law the amount of heat energy radiated by the Earth's surface is proportional to (T(sup 4)). However, if the planet has a substantial atmosphere, it can absorb all infrared radiation from the lower surface before the radiation penetrates into outer space. Thus, an instrument in space looking at the planet does not detect radiation from the surface. The radiation it sees comes from some level higher up. For the earth#s atmosphere the effective temperature (T(sub e)) has a value of 255 K corresponding to the middle troposphere, above most of the

  7. The effects of general relativity on near-earth satellites

    NASA Technical Reports Server (NTRS)

    Ries, J. C.; Watkins, M. M.; Tapley, B. D.; Huang, C.

    1990-01-01

    Whether one uses a solar system barycentric frame or a geocentric frame when including the general theory of relativity in orbit determination for near-earth satellites, the results should be equivalent to some limiting accuracy. The purpose of this paper is to clarify the effects of relativity in each frame and to demonstrate their equivalence through the analysis of three years of laser tracking data taken on the Lageos satellite. It is demonstrated that the simpler formulation in the geocentric frame is adequate for the purpose of near-earth satellite orbit determination. A correction to the conventional barycentric equations of motion is shown to be required.

  8. Systematic Effects in Earth Orientation Parameters Determined by VLBI

    NASA Astrophysics Data System (ADS)

    Schuh, H.; Heinkelmann, R.

    2015-12-01

    Very Long Baseline Interferometry (VLBI) is the only technique that directly connects on the observation level the realizations of ITRS and ICRS in terms of their orientation. Many applications in spacecraft navigation, fundamental astronomy, astrometry and geosciences depend on the Earth Orientation Parameters (EOP) determined by VLBI. Currently, under the IAG/IAU Joint Working Group on the Theory of Earth Rotation, activities are supported to advance the theory of Earth rotation. Some components of Earth Rotation, such as the free modes like the Free Core Nutation (FCN) are not predictable but rely entirely on the observation through VLBI. In our presentation we investigate the EOP when alternating various VLBI analysis options such as correction models, a priori parameters, and other choices with the aim to detect and quantify possible systematic effects. Our approach is purely empirical: we alternate certain analysis options and assess the differences with respect to the reference solution that adheres to the IERS Conventions (2010) and applies the standard parameterization. For demonstration we analyze the regular International VLBI Service for Geodesy and Astrometry (IVS) sessions IVS-R1 and IVS-R4.The IAG flagship component GGOS (Global Geodetic Observing System) aims to provide the EOP with an accuracy of 1 mm on the Earth surface (about 30 microarcseconds). This accuracy target will be applied as a limit to interpret the significance of the differences obtained in our comparisons.

  9. A review of ionospheric effects on Earth-space propagation

    NASA Technical Reports Server (NTRS)

    Klobuchar, J. A.

    1984-01-01

    A short description is given of each ionospheric total electron content (TEC) effect upon radio waves, along with a representative value of the magnitude of each of these effects under normal ionospheric conditions. A discussion is given of the important characteristics of average ionospheric TEC behavior and the temporal and spatial variability of TEC. Radio waves undergo several effects when they pass through the Earth's ionosphere. One of the most important of these effects is a retardation, or group delay, on the modulation or information carried on the radio wave that is due to its encounter with the free, thermal electrons in the Earth's ionosphere. Other effects the ionosphere has on radio waves include: radio frequency (RF) carrier phase advance; Doppler shift of the RF carrier of the radio wave; Faraday rotation of the plane of polarization of linearly polarized waves; angular refraction or bending of the radio wave path as it travels through the ionosphere; and amplitude and phase scintillations.

  10. Understanding and prediction of electronic-structure-driven physical behaviors in rare-earth compounds.

    PubMed

    Paudyal, Durga; Pathak, Arjun K; Pecharsky, V K; Gschneidner, K A

    2013-10-02

    Rare-earth materials, due to their unique magnetic properties, are important for fundamental and technological applications such as advanced magnetic sensors, magnetic data storage, magnetic cooling and permanent magnets. For an understanding of the physical behaviors of these materials, first principles techniques are one of the best theoretical tools to explore the electronic structure and evaluate exchange interactions. However, first principles calculations of the crystal field splitting due to intra-site electron-electron correlations and the crystal environment in the presence of exchange splitting in rare-earth materials are rarely carried out despite the importance of these effects. Here we consider rare-earth dialuminides as model systems and show that the low temperature anomalies observed in these systems are due to the variation of both exchange and crystal field splitting leading to anomalous intra-site correlated-4f and itinerant-5d electronic states near the Fermi level. From calculations supported by experiments we uncover that HoAl2 is unique among rare-earth dialuminides, in that it undergoes a cubic to orthorhombic distortion leading to a spin reorientation. Calculations of a much more extended family of mixed rare-earth dialuminides reveal an additional degree of complexity: the effective quadrupolar moment of the lanthanides changes sign as a function of lanthanide concentration, leading to a change in the sign of the anisotropy constant. At this point the quadrupolar interactions are effectively reduced to zero, giving rise to lattice instability and leading to new phenomena. This study shows a clear picture that accurate evaluation of the exchange, crystal field splitting and shape of the charge densities allows one to understand, predict and control the physical behaviors of rare-earth materials.

  11. Dynamic ocean-tide effects on Earth's rotation

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1993-01-01

    This article develops 'broad-band' Liouville equations which are capable of determining the effects on the rotation of the Earth of a periodic excitation even at frequencies as high as semi-diurnal; these equations are then used to predict the rotational effects of altimetric, numerical and 32-constituent spherical harmonic ocean-tide models. The rotational model includes a frequency-dependent decoupled core, the effects of which are especially marked near retrograde diurnal frequencies; and a fully dynamic oceanic response, whose effects appear to be minor despite significant frequency dependence. The model also includes solid-earth effects which are frequency dependent as the result of both anelasticity at long periods and the fluid-core resonance at nearly diurnal periods. The effects of both tidal inertia and relative angular momentum on Earth rotation (polar motion, length of day, 'nutation' and Universal Time) are presented for 32 long- and short-period ocean tides determined as solutions to the author's spherical harmonic tide theory. The lengthening of the Chandler wobble period by the pole tide is also re-computed using the author's full theory. Additionally, using the spherical harmonic theory, tidal currents and their effects on rotation are determined for available numerical and altimetric tide height models. For all models, we find that the effects of tidal currents are at least as important as those of tide height for diurnal and semi-diurnal constituents.

  12. Effects of megascale eruptions on Earth and Mars

    USGS Publications Warehouse

    Thordarson, T.; Rampino, M.; Keszthelyi, L.P.; Self, S.

    2009-01-01

    Volcanic features are common on geologically active earthlike planets. Megascale or "super" eruptions involving >1000 Gt of magma have occurred on both Earth and Mars in the geologically recent past, introducing prodigious volumes of ash and volcanic gases into the atmosphere. Here we discuss felsic (explosive) and mafi c (flood lava) supereruptions and their potential atmospheric and environmental effects on both planets. On Earth, felsic supereruptions recur on average about every 100-200,000 years and our present knowledge of the 73.5 ka Toba eruption implies that such events can have the potential to be catastrophic to human civilization. A future eruption of this type may require an unprecedented response from humankind to assure the continuation of civilization as we know it. Mafi c supereruptions have resulted in atmospheric injection of volcanic gases (especially SO2) and may have played a part in punctuating the history of life on Earth. The contrast between the more sustained effects of flood basalt eruptions (decades to centuries) and the near-instantaneous effects of large impacts (months to years) is worthy of more detailed study than has been completed to date. Products of mafi c supereruptions, signifi cantly larger than known from the geologic record on Earth, are well preserved on Mars. The volatile emissions from these eruptions most likely had global dispersal, but the effects may not have been outside what Mars endures even in the absence of volcanic eruptions. This is testament to the extreme variability of the current Martian atmosphere: situations that would be considered catastrophic on Earth are the norm on Mars. ?? 2009 The Geological Society of America.

  13. A very sensitive high-resolution NMR method for quadrupolar nuclei: SPAM-DQF-STMAS.

    PubMed

    Amoureux, Jean-Paul; Flambard, Alexandrine; Delevoye, Laurent; Montagne, Lionel

    2005-07-21

    We show that by combining the intrinsically larger (with respect to MQMAS) efficiency of Double-Quantum Filtered Satellite-Transition MAS (DQF-STMAS), with the large S/N gain of the Soft-Pulse Added Mixing (SPAM) concept, a new very sensitive high-resolution solid-state NMR method can be obtained for semi-integer quadrupolar nuclei.

  14. Design of Scalable and Effective Earth Science Collaboration Tool

    NASA Astrophysics Data System (ADS)

    Maskey, M.; Ramachandran, R.; Kuo, K. S.; Lynnes, C.; Niamsuwan, N.; Chidambaram, C.

    2014-12-01

    Collaborative research is growing rapidly. Many tools including IDEs are now beginning to incorporate new collaborative features. Software engineering research has shown the effectiveness of collaborative programming and analysis. In particular, drastic reduction in software development time resulting in reduced cost has been highlighted. Recently, we have witnessed the rise of applications that allow users to share their content. Most of these applications scale such collaboration using cloud technologies. Earth science research needs to adopt collaboration technologies to reduce redundancy, cut cost, expand knowledgebase, and scale research experiments. To address these needs, we developed the Earth science collaboration workbench (CWB). CWB provides researchers with various collaboration features by augmenting their existing analysis tools to minimize learning curve. During the development of the CWB, we understood that Earth science collaboration tasks are varied and we concluded that it is not possible to design a tool that serves all collaboration purposes. We adopted a mix of synchronous and asynchronous sharing methods that can be used to perform collaboration across time and location dimensions. We have used cloud technology for scaling the collaboration. Cloud has been highly utilized and valuable tool for Earth science researchers. Among other usages, cloud is used for sharing research results, Earth science data, and virtual machine images; allowing CWB to create and maintain research environments and networks to enhance collaboration between researchers. Furthermore, collaborative versioning tool, Git, is integrated into CWB for versioning of science artifacts. In this paper, we present our experience in designing and implementing the CWB. We will also discuss the integration of collaborative code development use cases for data search and discovery using NASA DAAC and simulation of satellite observations using NASA Earth Observing System Simulation

  15. Semi-empirical refinements of crystal structures using (17)O quadrupolar-coupling tensors.

    PubMed

    Holmes, Sean T; Iuliucci, Robbie J; Mueller, Karl T; Dybowski, Cecil

    2017-02-14

    We demonstrate a modification of Grimme's two-parameter empirical dispersion force field (referred to as the PW91-D2* method), in which the damping function has been optimized to yield geometries that result in predictions of the principal values of (17)O quadrupolar-coupling tensors that are systematically in close agreement with experiment. The predictions of (17)O quadrupolar-coupling tensors using PW91-D2*-refined structures yield a root-mean-square deviation (RMSD) (0.28 MHz) for twenty-two crystalline systems that is smaller than the RMSD for predictions based on X-ray diffraction structures (0.58 MHz) or on structures refined with PW91 (0.53 MHz). In addition, (13)C, (15)N, and (17)O chemical-shift tensors and (35)Cl quadrupolar-coupling tensors determined with PW91-D2*-refined structures are compared to the experiment. Errors in the prediction of chemical-shift tensors and quadrupolar-coupling tensors are, in these cases, substantially lowered, as compared to predictions based on PW91-refined structures. With this PW91-D2*-based method, analysis of 42 (17)O chemical-shift-tensor principal components gives a RMSD of only 18.3 ppm, whereas calculations on unrefined X-ray structures give a RMSD of 39.6 ppm and calculations of PW91-refined structures give an RMSD of 24.3 ppm. A similar analysis of (35)Cl quadrupolar-coupling tensor principal components gives a RMSD of 1.45 MHz for the unrefined X-ray structures, 1.62 MHz for PW91-refined structures, and 0.59 MHz for the PW91-D2*-refined structures.

  16. The effects of the solid inner core and nonhydrostatic structure on the earth's forced nutations and earth tides

    NASA Technical Reports Server (NTRS)

    De Vries, Dan; Wahr, John M.

    1991-01-01

    This paper computes the effects of the solid inner core (IC) on the forced nutations and earth tides, and on certain of the earth's rotational normal modes. The theoretical results are extended to include the effects of a solid IC and of nonhydrostatic structure. The presence of the IC is responsible for a new, almost diurnal, prograde normal mode which involves a relative rotation between the IC and fluid outer core about an equatorial axis. It is shown that the small size of the IC's effects on both nutations and tides is a consequence of the fact that the IC's moments of inertia are less than 1/1000 of the entire earth's.

  17. Spin-locking of half-integer quadrupolar nuclei in NMR of solids: The far off-resonance case.

    PubMed

    Odedra, Smita; Wimperis, Stephen

    2016-11-30

    Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of large resonance offsets has been studied using both approximate and exact theoretical approaches and, in the case of I=3/2, experimentally. We show the variety of coherences and population states produced in a far off-resonance spin-locking NMR experiment (one consisting solely of a spin-locking pulse) and how these vary with the radiofrequency field strength and offset frequency. Under magic angle spinning (MAS) conditions and in the "adiabatic limit", these spin-locked states acquire a time dependence. We discuss the rotor-driven interconversion of the spin-locked states, using an exact density matrix approach to confirm the results of the approximate model. Using conventional and multiple-quantum filtered spin-locking (23)Na (I=3/2) NMR experiments under both static and MAS conditions, we confirm the results of the theoretical calculations, demonstrating the applicability of the approximate theoretical model to the far off-resonance case. This simplified model includes only the effects of the initial rapid dephasing of coherences that occurs at the start of the spin-locking period and its success in reproducing both experimental and exact simulation data indicates that it is this dephasing that is the dominant phenomenon in NMR spin-locking of quadrupolar nuclei, as we have previously found for the on-resonance and near-resonance cases. Potentially, far off-resonance spin-locking of quadrupolar nuclei could be of interest in experiments such as cross polarisation as a consequence of the spin-locking pulse being applied to a better defined initial state (the thermal equilibrium bulk magnetisation aligned along the z-axis) than can be created in a powdered solid with a selective radiofrequency pulse, where the effect of the pulse depends on the orientation of the individual crystallites.

  18. Magnetostatic Effects in the Nucleation of Rare Earth Ferromagnetic Phases

    SciTech Connect

    Durfee, C. S.; Flynn, C. P.

    2001-07-30

    It has been reported that superheating, supercooling, and explosive kinetics coupled to other degrees of freedom occur at the ferromagnetic transitions of Er and Dy, and that metastable phases occur during the transition kinetics of Er. We explain these observations in terms of magnetostatic energy, which requires highly eccentric nuclei in the homogeneous nucleation of magnetic transitions in heavy rare earths. The magnetostatics favor transitions through ferrimagnetic intermediaries. The unusual kinetics derive from effective spin lattice relaxation.

  19. Earth matter effect on active-sterile neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Acero, Mario A.; Aguilar-Arevalo, Alexis A.; D'Olivo, J. C.

    2011-08-01

    Oscillations between active and sterile neutrinos remain as an open possibility to explain some experimental observations. In a four-neutrino mixing scheme, we use the Magnus expansion of the evolution operator to study the evolution of neutrino flavor amplitudes within the Earth. We apply this formalism to calculate the transition probabilities from active to sterile neutrinos taking into account the matter effect for a varying terrestrial density.

  20. On the tidal effects in the motion of earth satellites and the love parameters of the earth

    NASA Technical Reports Server (NTRS)

    Musen, P.; Estes, R.

    1972-01-01

    The tidal effects in the motion of artificial satellites are studied to determine the elastic properties of the earth as they are observed from extraterrestrial space. Considering Love numbers, the disturbing potential is obtained as the analytical continuation of the tidal potential from the surface of the earth into-outer space, with parameters which characterize the earth's elastic response to tidal attraction by the moon and the sun. It is concluded that the tidal effects represent a superposition of a large number of periodic terms, and the rotation of the lunar orbital plane produces a term of 18 years period in tidal perturbations of the ascending node of the satellite's orbit.

  1. Three-Dimensional Orbits of Earth Satellites, Including Effects of Earth Oblateness and Atmospheric Rotation

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N.; Goodwin, Frederick K.; Mersman, William A.

    1958-01-01

    The principal purpose of the present paper is to present sets of equations which may be used for calculating complete trajectories of earth satellites from outer space to the ground under the influence of air drag and gravity, including oblateness effects, and to apply these to several examples of entry trajectories starting from a circular orbit. Equations of motion, based on an "instantaneous ellipse" technique, with polar angle as independent variable, were found suitable for automatic computation of orbits in which the trajectory consists of a number of revolutions. This method is suitable as long as the trajectory does not become nearly vertical. In the terminal phase of the trajectories, which are nearly vertical, equations of motion in spherical polar coordinates with time as the independent variable were found to be more suitable. In the first illustrative example the effects of the oblateness component of the earth's gravitational field and of atmospheric rotation were studied for equatorial orbits. The satellites were launched into circular orbits at a height of 120 miles, an altitude sufficiently high that a number of revolutions could be studied. The importance of the oblateness component of the earth's gravitational field is shown by the fact that a satellite launched at circular orbital speed, neglecting oblateness, has a perigee some 67,000 feet lower when oblateness forces are included in the equations of motion than when they are not included. Also, the loss in altitude per revolution is double that of a satellite following an orbit not subject to oblateness. The effect of atmospheric rotation on the loss of altitude per revolution was small. As might be surmised, the regression of the line of nodes as predicted by celestial mechanics is unchanged when drag is included. It is clear that the inclination of the orbital plane to the equator will be relatively unaffected by drag for no atmospheric rotation since the drag lies in the orbital plane in

  2. Relativistic effects in earth-orbiting Doppler lidar return signals.

    PubMed

    Ashby, Neil

    2007-11-01

    Frequency shifts of side-ranging lidar signals are calculated to high order in the small quantities (v/c), where v is the velocity of a spacecraft carrying a lidar laser or of an aerosol particle that scatters the radiation back into a detector (c is the speed of light). Frequency shift measurements determine horizontal components of ground velocity of the scattering particle, but measured fractional frequency shifts are large because of the large velocities of the spacecraft and of the rotating earth. Subtractions of large terms cause a loss of significant digits and magnify the effect of relativistic corrections in determination of wind velocity. Spacecraft acceleration is also considered. Calculations are performed in an earth-centered inertial frame, and appropriate transformations are applied giving the velocities of scatterers relative to the ground.

  3. Anomalous Hall Effect in a Feromagnetic Rare-Earth Cobalite

    NASA Technical Reports Server (NTRS)

    Samoilov, A. V.; Yeh, N. C.; Vasquez, R. P.

    1996-01-01

    Rare-Earth manganites and cobalites with the perovskite structure have been a subject of great recent interest because their electrical resistance changes significantly when a magnetic field is applied...we have studied the Hall effect in thin film La(sub 0.5)Ca(sub 0.5)CoO(sub 3) material and have obtained convincing evidence fo the so called anomalous Hall effect, typical for magnetic metals...Our results suggest that near the ferromagnetic ordering temperature, the dominant electron scattering mechanism is the spin fluctuation.

  4. Effect of rare earth oxides for improvement of MCFC

    NASA Astrophysics Data System (ADS)

    Ota, Ken-ichiro; Matsuda, Yoshiyuki; Matsuzawa, Koichi; Mitsushima, Shigenori; Kamiya, Nobuyuki

    The solubility of rare earth metal oxides and their effect on the NiO solubility have been discussed to stabilize the cathode of molten carbonate fuel cells. The solubility of Ho, Yb, and Nd oxides were 4.4 × 10 -4, 3.4 × 10 -4, and 1.3 × 10 -3 (mole fraction) at 923 K, respectively. The solubilities of NiO in (Li 0.52/Na 0.48) 2CO 3 with the saturated Ho, Yb, and Nd were 1.57 × 10 -5, 1.41 × 10 -5, and 9.5 × 10 -6, respectively. Among these three, Nd, which has the highest solubility in the carbonates, reduced the NiO solubility most; although, the La reduced the NiO solubility more than Nd. The logarithm of the solubility of the rare earth metal oxides has a linear relation to the Coulomb force ratio between the rare earth metal and the alkaline metal. Following this relation, the La should have the highest solubility among all the lanthanides. The basicity which NiO solubility closely relates has a linear relationship to the Coulomb force parameter of the melts. Based on these two models, the La would be the best additive to reduce the NiO solubility in Li/Na eutectic carbonate melt, among all the lanthanides.

  5. Atmospheric effects on earth rotation and polar motion

    NASA Technical Reports Server (NTRS)

    Salstein, David A.

    1988-01-01

    The variability in the earth's rotation rate not due to known solid body tides is dominated on time scales of about four years and less by variations in global atmospheric angular momentum (M) as derived from the zonal wind distribution. Among features seen in the length of day record produced by atmospheric forcing are the strong seasonal cycle, quasi-periodic fluctuations around 40-50 days, and an interannual signal forced by a strong Pacific warming event known as the El Nino. Momentum variations associated with these time scales arise in different latitudinal regions. Furthermore, winds in the stratosphere make a particularly important contribution to seasonal variability. Other related topics discussed here are: (1) comparisons of the M series from wind fields produced at different weather centers; (2) the torques that dynamically link the atmosphere and earth; and (3) longer-term nonatmospheric effects that can be seen upon removal of the atmospheric signal.an interestigapplication for climatological purposes is the use of the historical earth rotation series as a proxy for atmospheric wind variability prior to the era of upper-air data. Lastly, results pertaining to the role of atmospheric pressure systems in exciting rapid polar motion are presented.

  6. Indirect measurement of N-14 quadrupolar coupling for NH3 intercalated in potassium graphite

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Fronko, R. M.; Resing, H. A.

    1987-01-01

    A method for indirect measurement of the nuclear quadrupolar coupling was developed and applied to NH3 molecules in the graphite intercalation compound K(NH3)4.3C24, which has a layered structure with alternating carbon and intercalant layers. Three triplets were observed in the H-1 NMR spectra of the compound. The value of the N-14 quadrupolar coupling constant of NH3 (3.7 MHz), determined indirectly from the H-1 NMR spectra, was intermediate between the gas value of 4.1 MHz and the solid-state value of 3.2 MHz. The method was also used to deduce the (H-1)-(H-1) and (N-14)-(H-1) dipolar interactions, the H-1 chemical shifts, and the molecular orientations and motions of NH3.

  7. H_2 bipolar emission associated with the quadrupolar molecular outflow in L723

    NASA Astrophysics Data System (ADS)

    Palacios, Javier; Eiroa, Carlos

    1999-06-01

    We present near-infrared images of the quadrupolar CO outflow in L723, formed by two lobe pairs of different size. Bipolar molecular hydrogen line emission is detected, approximately centered on the Class 0 source L723 VLA2. One of the observed H_2 nebulosities coincides with the Herbig-Haro object HH 223. The H_2 bipolar outflow is projected against the large lobe pair of the quadrupolar CO outflow. Position angles of the H_2 and HH emissions, large CO lobe pair and the thermal radio jet VLA2 are similar and also close to the magnetic field direction in the region. All these phenomena are likely powered by the young protostellar object L723 VLA2. Our near-infrared images do not show any near-ir counterpart of the smaller CO pair, whose origin and driving source remain unclear.

  8. Perturbed chain-statistical associating fluid theory extended to dipolar and quadrupolar molecular fluids.

    PubMed

    Karakatsani, Eirini K; Economou, Ioannis G

    2006-05-11

    The perturbed chain statistical associating fluid theory (PC-SAFT) is extended to polar molecular fluids, namely dipolar and quadrupolar fluids. The extension is based on the perturbation theory for polar fluids by Stell and co-workers. Appropriate expressions are proposed for dipole-dipole, quadrupole-quadrupole, and dipole-quadrupole interactions. Furthermore, induced dipole interactions are calculated explicitly in the model. The new polar PC-SAFT model is relatively complex; for this purpose, a truncated polar PC-SAFT model is proposed using only the leading term in the polynomial expansion for polar interactions. The new model is used for the calculation of thermodynamic properties of various quadrupolar pure fluids. In all cases, the agreement between experimental data and model predictions is very good.

  9. Quantum phases of quadrupolar Fermi gases in coupled one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Min; Lahrz, M.; Mathey, L.

    2014-01-01

    Following the recent proposal to create quadrupolar gases [Bhongale et al., Phys. Rev. Lett. 110, 155301 (2013), 10.1103/PhysRevLett.110.155301], we investigate what quantum phases can be created in these systems in one dimension. We consider a geometry of two coupled one-dimensional (1D) systems, and derive the quantum phase diagram of ultracold fermionic atoms interacting via quadrupole-quadrupole interactions within a Tomonaga-Luttinger-liquid framework. We map out the phase diagram as a function of the distance between the two tubes and the angle between the direction of the tubes and the quadrupolar moments. The latter can be controlled by an external field. We show that there are two magic angles θB,1c and θB,2c between 0 and π /2, where the intratube quadrupolar interactions vanish and change signs. Adopting a pseudospin language with regard to the two 1D systems, the system undergoes a spin-gap transition and displays a zigzag density pattern, above θB,2c and below θB,1c. Between the two magic angles, we show that polarized triplet superfluidity and a planar spin-density-wave order compete with each other. The latter corresponds to a bond-order solid in higher dimensions. We demonstrate that this order can be further stabilized by applying a commensurate periodic potential along the tubes.

  10. The effect of atmospheric pressure on Snowball Earth deglaciation

    NASA Astrophysics Data System (ADS)

    Edkins, Nicholas; Davies, Roger

    2017-02-01

    The most common explanation for the escape from a Snowball Earth state involves, among other factors, a strong greenhouse effect caused by a large partial pressure of CO2. This leads to an increase in surface pressure, which most models do not account for. With a higher surface pressure, pressure broadening increases, and convection reaches a deeper layer, both of which result in higher surface temperatures. The latter mechanism, which has not previously been reported, is found to be a greater source of warming than pressure broadening in the normal range of CO2 partial pressures at the point of deglaciation.

  11. The thermodynamic effect of atmospheric mass on early Earth's temperature

    NASA Astrophysics Data System (ADS)

    Chemke, R.; Kaspi, Y.; Halevy, I.

    2016-11-01

    Observations suggest that Earth's early atmospheric mass differed from the present day. The effects of a different atmospheric mass on radiative forcing have been investigated in climate models of variable sophistication, but a mechanistic understanding of the thermodynamic component of the effect of atmospheric mass on early climate is missing. Using a 3-D idealized global circulation model (GCM), we systematically examine the thermodynamic effect of atmospheric mass on near-surface temperature. We find that higher atmospheric mass tends to increase the near-surface temperature mostly due to an increase in the heat capacity of the atmosphere, which decreases the net radiative cooling effect in the lower layers of the atmosphere. Additionally, the vertical advection of heat by eddies decreases with increasing atmospheric mass, resulting in further near-surface warming. As both net radiative cooling and vertical eddy heat fluxes are extratropical phenomena, higher atmospheric mass tends to flatten the meridional temperature gradient.

  12. Magnus Effect on a Spinning Satellite in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Ramjatan, Sahadeo; Fitz-Coy, Norman; Yew, Alvin Garwai

    2016-01-01

    A spinning body in a flow field generates an aerodynamic lift or Magnus effect that displaces the body in a direction normal to the freestream flow. Earth orbiting satellites with substantial body rotation in appreciable atmospheric densities may generate a Magnus force to perturb orbital dynamics. We investigate the feasibility of using this effect for spacecraft at a perigee of 80km using the Systems Tool Kit (STK). Results show that for a satellite of reasonable properties, the Magnus effect doubles the amount of time in orbit. Orbital decay was greatly mitigated for satellites spinning at 10000 and 15000RPM. This study demonstrates that the Magnus effect has the potential to sustain a spacecraft's orbit at a low perigee altitude and could also serve as an orbital maneuver capability.

  13. The radiative effect of aerosols in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wang, W.-C.; Domoto, G. A.

    1974-01-01

    A modified two-flux approximation is employed to compute the transfer of radiation in a finite, inhomogeneous, turbid atmosphere. A perturbation technique is developed to allow the treatment of nongray gaseous absorption with multiple scattering. The perturbation method, which employs a backscatter factor as a parameter, can be used with anisotropic particle scattering as well as Rayleigh scattering. This method is used to study the effect of aerosols on radiative solar heating and infrared cooling as well as the radiative-convective temperature distribution in the earth's atmosphere. It is found that the effect of aerosols in the infrared cannot be neglected; while in the visible, the effect can be of the same order as that due to absorption by water vapor. For a high surface albedo (greater than 0.30) heating of the earth-atmosphere system results due to the presence of aerosols. The aerosols also reduce the amount of convection needed to maintain a stable atmosphere. For the case of a dense haze a temperature inversion is found to exist close to the ground.

  14. The Effect of Dark Matter on Solar System and Perihelion Precession of Earth Planet

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan; Mousavi, S. N.; Saadat, M.; Saadat, N.; Saadat, A. M.

    2010-10-01

    This paper visualizes effect of dark matter on solar system and especially perihelion precession of Earth planet. The relation between the rate of perihelion shift of Earth planet and dark matter are obtained.

  15. WIMP capture and annihilation in the Earth in effective theories

    NASA Astrophysics Data System (ADS)

    Catena, Riccardo

    2017-01-01

    I calculate the rate of WIMP capture and annihilation in the Earth in the non-relativistic effective theory of dark matter-nucleon interactions. Neglecting operator interference, I consider all Galilean invariant interaction operators that can arise from the exchange of a heavy particle of spin less than or equal to one when WIMPs have spin 0, 1/2 or 1. I compute position and shape of the expected resonances in the mass—capture rate plane and show that Iron is not the most important element in the capture process for many currently ignored interaction operators. I compare these predictions with the recent results of an Earth WIMP analysis of IceCube in the 86-string configuration and set limits on all isoscalar and isovector coupling constants of the effective theory of dark matter-nucleon interactions. For certain interaction operators and for a dark matter particle mass of about 50 GeV, I find that these limits are stronger than those I have previously derived in an analysis of the solar WIMP search performed at IceCube in the 79-string configuration.

  16. Fate of Earth Microbes on Mars -- UV Radiation Effects

    NASA Technical Reports Server (NTRS)

    Cockell, Charles

    2000-01-01

    A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment. Biological action spectra for DNA inactivation are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Although the present-day martian UV flux is similar to early earth and thus may not be a limitation to life in the evolutionary context, it is a constraint to an unadapted biota and will rapidly kill spacecraft-borne microbes not covered by a martian dust layer. Here calculations for loss of microbial viability on the Pathfinder and Polar lander spacecraft are presented and the effects of martian dust on loss of viability are discussed. Details of the radiative transfer model are presented.

  17. Fate of Earth Microbes on Mars: UV Radiation Effects

    NASA Technical Reports Server (NTRS)

    Cockell, Charles

    2000-01-01

    A radiative transfer model is used to quantitatively investigate aspects of the martian ultraviolet radiation environment. Biological action spectra for DNA inactivation are used to estimate biologically effective irradiances for the martian surface under cloudless skies. Although the present-day martian UV flux is similar to early earth and thus may not be a limitation to life in the evolutionary context, it is a constraint to an unadapted biota and will rapidly kill spacecraft-borne microbes not covered by a martian dust layer. Here calculations for loss of microbial viability on the Pathfinder and Polar lander spacecraft are presented and the effects of martian dust on loss of viability are discussed. Details of the radiative transfer model are presented.

  18. Atomic oxygen effects on POSS polyimides in low earth orbit.

    PubMed

    Minton, Timothy K; Wright, Michael E; Tomczak, Sandra J; Marquez, Sara A; Shen, Linhan; Brunsvold, Amy L; Cooper, Russell; Zhang, Jianming; Vij, Vandana; Guenthner, Andrew J; Petteys, Brian J

    2012-02-01

    Kapton polyimde is extensively used in solar arrays, spacecraft thermal blankets, and space inflatable structures. Upon exposure to atomic oxygen in low Earth orbit (LEO), Kapton is severely eroded. An effective approach to prevent this erosion is to incorporate polyhedral oligomeric silsesquioxane (POSS) into the polyimide matrix by copolymerizing POSS monomers with the polyimide precursor. The copolymerization of POSS provides Si and O in the polymer matrix on the nano level. During exposure of POSS polyimide to atomic oxygen, organic material is degraded, and a silica passivation layer is formed. This silica layer protects the underlying polymer from further degradation. Laboratory and space-flight experiments have shown that POSS polyimides are highly resistant to atomic-oxygen attack, with erosion yields that may be as little as 1% those of Kapton. The results of all the studies indicate that POSS polyimide would be a space-survivable replacement for Kapton on spacecraft that operate in the LEO environment.

  19. Adiabatic sweep cross-polarization magic-angle-spinning NMR of half-integer quadrupolar spins

    NASA Astrophysics Data System (ADS)

    Wi, Sungsool; Kim, Chul; Schurko, Robert; Frydman, Lucio

    2017-04-01

    The use of frequency-swept radiofrequency (rf) pulses for enhancing signals in the magic-angle spinning (MAS) spectra of half-integer quadrupolar nuclides was explored. The broadband adiabatic inversion cross-polarization magic-angle spinning (BRAIN-CPMAS) method, involving an adiabatic inversion pulse on the S-channel and a simultaneous rectangular spin-lock pulse on the I-channel (1H), was applied to I(1/2) → S(3/2) systems. Optimal BRAIN-CPMAS matching conditions were found to involve low rf pulse strengths for both the I- and S-spin channels. At these low and easily attainable rf field strengths, level-crossing events among the energy levels | 3 / 2 >, | 1 / 2 >, | - 1 / 2 >, | - 3 / 2 > that are known to complicate the CPMAS of quadrupolar nuclei, are mostly avoided. Zero- and double-quantum polarization transfer modes, akin to those we have observed for I(1/2) → S(1/2) polarization transfers, were evidenced by these analyses even in the presence of the quadrupolar interaction. 1H-23Na and 1H-11B BRAIN-CPMAS conditions were experimentally explored on model compounds by optimizing the width of the adiabatic sweep, as well as the rf pulse powers of the 1H and 23Na/11B channels, for different MAS rates. The experimental data obtained on model compounds containing spin-3/2 nuclides, matched well predictions from numerical simulations and from an average Hamiltonian theory model. Extensions to half-integer spin nuclides with higher spins and potential applications of this BRAIN-CPMAS approach are discussed.

  20. Quadrupolar benzobisthiazole-cored arylamines as highly efficient two-photon absorbing fluorophores.

    PubMed

    Hrobárik, Peter; Hrobáriková, Veronika; Semak, Vladislav; Kasák, Peter; Rakovský, Erik; Polyzos, Ioannis; Fakis, Mihalis; Persephonis, Peter

    2014-12-19

    A computer-aided design of novel D-π-A-π-D styrylamines containing five isomeric benzobisthiazole moieties as the electron-accepting core has revealed the linear centrosymmetric benzo[1,2-d:4,5-d']bisthiazole as the most promising building block for engineering chromophores displaying high two-photon absorption (TPA) in the near-IR region, as also confirmed experimentally. The ease of synthesis of quadrupolar derivatives thereof, combined with extraordinarly high TPA action cross sections (δTPAΦf > 1500 GM), makes these heteroaromatic systems particularly attractive as diagnostic agents in 3D fluorescence imaging.

  1. Pulsed field gradient multiple-quantum MAS NMR spectroscopy of half-integer spin quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Fyfe, C. A.; Skibsted, J.; Grondey, H.; Meyer zu Altenschildesche, H.

    1997-12-01

    Pulsed field gradients (PFGs) have been applied to select coherence transfer pathways in multiple-quantum (MQ) MAS NMR spectra of half-integer spin quadrupolar nuclei in rigid solids. 27Al triple-quantum (3Q) MAS NMR spectra of the aluminophosphate molecular sieves VPI-5 and AlPO 4-18 have been used to demonstrate the selection of the (0)→(3)→(-1) coherence transfer pathway using PFGs and no phase cycling. Compared to MQMAS experiments that employ phase cycling schemes, the main advantage of the PFG-MQMAS technique is its simplicity, which should facilitate the combination of MQMAS with other pulse sequences.

  2. Excited-state symmetry breaking of linear quadrupolar chromophores: A transient absorption study

    NASA Astrophysics Data System (ADS)

    Dozova, Nadia; Ventelon, Lionel; Clermont, Guillaume; Blanchard-Desce, Mireille; Plaza, Pascal

    2016-11-01

    The photophysical properties of two highly symmetrical quadrupolar chromophores were studied by both steady-state and transient absorption spectroscopy. Their excited-state behavior is dominated by the solvent-induced Stokes shift of the stimulated-emission band. The origin of this shift is attributed to symmetry breaking that confers a non-vanishing dipole moment to the excited state of both compounds. This dipole moment is large and constant in DMSO, whereas symmetry breaking appears significantly slower and leading to smaller excited-state dipole in toluene. Time-dependant increase of the excited-state dipole moment induced by weak solvation is proposed to explain the results in toluene.

  3. Magnetic dipolar and quadrupolar transitions in two-electron atoms under exponential-cosine-screened Coulomb potential

    SciTech Connect

    Modesto-Costa, Lucas; Canuto, Sylvio; Mukherjee, Prasanta K.

    2015-03-15

    A detailed investigation of the magnetic dipolar and quadrupolar excitation energies and transition probabilities of helium isoelectronic He, Be{sup 2+}, C{sup 4+}, and O{sup 6+} have been performed under exponential cosine screened Coulomb potential generated in a plasma environment. The low-lying excited states 1s{sup 2}:{sup 1}S{sup e} → 1sns:{sup 3}S{sup e}{sub 0}, and 1snp:{sup 3}P{sup o}{sub 2} (n = 2, 3, 4, and 5) are considered. The variational time-dependent coupled Hartree-Fock scheme has been used. The effect of the confinement produced by the potential on the structural properties is investigated for increasing coupling strength of the plasma. It is noted that there is a gradual destabilization of the energy of the system with the reduction of the ionization potential and the number of excited states. The effect of the screening enhancement on the excitation energies and transition probabilities has also been investigated and the results compared with those available for the free systems and under the simple screened Coulomb potential.

  4. 5f delocalization-induced suppression of quadrupolar order in U(Pd1-xPtx)₃

    DOE PAGES

    Walker, H. C.; Le, M. D.; McEwen, K. A.; ...

    2011-12-27

    We present bulk magnetic and transport measurements and x-ray resonant scattering measurements on U(Pd1-xPtx)₃ for x=0.005 and 0.01, which demonstrate the high sensitivity of the quadrupolar order in the canonical antiferroquadrupolar ordered system UPd₃ to doping with platinum. Bulk measurements for x=0.005 reveal behavior similar to that seen in UPd₃, albeit at a lower temperature, and x-ray resonant scattering provides evidence of quadrupolar order described by the Qxy order parameter. In contrast, bulk measurements reveal only an indistinct transition in x=0.01, consistent with the observation of short-range quadrupolar order in our x-ray resonant scattering results.

  5. Effects of the low Earth orbital environment on spacecraft materials

    NASA Technical Reports Server (NTRS)

    Leger, L. J.

    1986-01-01

    It is evident from space flights during the last three years that the low Earth orbital (LEO) environment interacts with spacecraft surfaces in significant ways. One manifestation of these interactions is recession of, in particular, organic-polymer-based surfaces presumably due to oxidation by atomic oxygen, the major component of the LEO environment. Three experiments have been conducted on Space Shuttle flights 5, 8 and 41-G to measure reaction rates and the effects of various parameters on reaction rates. Surface recession on these flights indicates reaction efficiencies approximately 3 x 10(-24) cu cm/atoms for unfilled organic polymers. Of the metals, silver and osmium are very reactive. Effects on spacecraft or experiment surfaces can be evaluated using the derived reaction efficiencies and a definition of the total exposure to atomic oxygen. This exposure is obtained using an ambient density model, solar activity data and spacecraft parameters of altitude, attitude and operational date. Oxygen flux on a given surface is obtained from the ambient density and spacecraft velocity and can then be integrated to provide the total exposure or fluence. Such information can be generated using simple computational programs and can be converted to various formats. Overall, the extent of damage is strongly dependent on the type of surface and total exposure time.

  6. Laboratory simulation of Low Earth Orbit (LEO) atomic oxygen effects

    NASA Technical Reports Server (NTRS)

    Caledonia, George E.; Krech, Robert H.; Oakes, David B.

    1994-01-01

    A pulsed fast oxygen atom source has been used extensively over the last 7 years to investigate the effects of ambient oxygen atoms impacting materials placed in low Earth orbit. In this period, we irradiated well over 2000 material samples with 8 km/s oxygen atoms generated in our source. Typical irradiance level is 3 x 10(exp 20) O atoms/sq cm although some materials have been irradiated to fluence levels as high as 6 x 10(exp 21) O atoms/sq cm. The operating principles and characteristics of our source are reviewed along with diagnostic and handling procedures appropriate to material testing. Representative data is presented on the velocity dependence of oxygen atom erosion rates (the PSI source provides oxygen atoms tunable over the velocity range of 5 to 12 km/s) as well as the dependence on material temperature. Specific examples of non-linear oxidative effects related to surface contamination and test duration are also be provided.

  7. A study of isotropic-nematic transition of quadrupolar Gay-Berne fluid using density-functional theory approach

    NASA Astrophysics Data System (ADS)

    Singh, Ram Chandra; Ram, Jokhan

    2011-11-01

    The effects of quadrupole moments on the isotropic-nematic (IN) phase transitions are studied using the density-functional theory (DFT) for a Gay-Berne (GB) fluid for a range of length-to-breadth parameters ? in the reduced temperature range ? . The pair-correlation functions of the isotropic phase, which enter into the DFT as input parameters are found by solving the Percus-Yevick integral equation theory. The method used involves an expansion of angle-dependent functions appearing in the integral equations in terms of spherical harmonics and the harmonic coefficients are obtained by an iterative algorithm. All the terms of harmonic coefficients which involve l indices up to less than or equal to 6 are considered. The numerical accuracy of the results depends on the number of spherical harmonic coefficients considered for each orientation-dependent function. As the length-to-breadth ratio of quadrupolar GB molecules is increased, the IN transition is seen to move to lower density (and pressure) at a given temperature. It has been observed that the DFT is good to study the IN transitions in such fluids. The theoretical results have also been compared with the computer simulation results wherever they are available.

  8. An electrorotation technique for measuring the dielectric properties of cells with simultaneous use of negative quadrupolar dielectrophoresis and electrorotation.

    PubMed

    Han, Song-I; Joo, Young-Don; Han, Ki-Ho

    2013-03-07

    This paper presents an effective electrorotation technique for measuring the dielectric properties of cells using a superposed electrical signal, which can simultaneously generate negative quadrupolar dielectrophoretic (nQDEP) force and electrorotational (ROT) torque. The proposed technique involves a three-dimensional (3D) octode, which includes four electrodes arranged in a crisscross pattern on the top and bottom of a microchannel, respectively. A single cell was trapped in the center of the 3D octode by the nQDEP force and simultaneously rotated by the ROT torque. Using the proposed electrorotation technique, ROT spectra of human leukocyte subpopulations (T and B lymphocytes, granulocytes, and monocytes) and metastatic human breast (SkBr3) and lung (A549) cancer cell lines were accurately measured without any disturbance. Torque on the cells generated by the ROT signal was analyzed theoretically based on the single-shell dielectric model for the cells. Furthermore, the dielectric properties of the cells, such as area-specific membrane capacitance and cytoplasm conductivity, were extracted using the measured ROT spectra and the analyzed torque.

  9. Investigating FAM-N pulses for signal enhancement in MQMAS NMR of quadrupolar nuclei.

    PubMed

    Colaux, Henri; Dawson, Daniel M; Ashbrook, Sharon E

    2017-01-18

    Although a popular choice for obtaining high-resolution solid-state NMR spectra of quadrupolar nuclei, the inherently low sensitivity of the multiple-quantum magic-angle spinning (MQMAS) experiment has limited its application for nuclei with low receptivity or when the available sample volume is limited. A number of methods have been introduced in the literature to attempt to address this problem. Recently, we have introduced an alternative, automated approach, based on numerical simulations, for generating amplitude-modulated pulses (termed FAM-N pulses) to enhance the efficiency of the triple- to single-quantum conversion step within MQMAS. This results in efficient pulses that can be used without experimental reoptimisation, ensuring that this method is particularly suitable for challenging nuclei and systems. In this work, we investigate the applicability of FAM-N pulses to a wider variety of systems, and their robustness under more challenging experimental conditions. These include experiments performed under fast MAS, nuclei with higher spin quantum numbers, samples with multiple distinct sites, low-γ nuclei and nuclei subject to large quadrupolar interactions.

  10. Earth curvature and atmospheric refraction effects on radar signal propagation.

    SciTech Connect

    Doerry, Armin Walter

    2013-01-01

    The earth isnt flat, and radar beams dont travel straight. This becomes more noticeable as range increases, particularly at shallow depression/grazing angles. This report explores models for characterizing this behavior.

  11. Effects of differentiation on the geodynamics of the early Earth

    NASA Astrophysics Data System (ADS)

    Piccolo, Andrea; Kaus, Boris; White, Richard; Johnson, Tim

    2016-04-01

    Archean geodynamic processes are not well understood, but there is general agreement that the mantle potential temperature was higher than present, and that as a consequence significant amounts of melt were produced both in the mantle and any overlying crust. This has likely resulted in crustal differentiation. An early attempt to model the geodynamic effects of differentiation was made by Johnson et al. (2014), who used numerical modeling to investigate the crust production and recycling in conjunction with representative phase diagrams (based on the inferred chemical composition of the primary melt in accordance with the Archean temperature field). The results of the simulations show that the base of the over-thickened primary basaltic crust becomes gravitational unstable due to the mineral assemblage changes. This instability leads to the dripping of dense material into the mantle, which causes an asthenospheric return flow, local partial melting and new primary crust generation that is rapidly recycled in to mantle. Whereas they gave important insights, the previous simulations were simplified in a number of aspects: 1) the rheology employed was viscous, and both elasticity and pressure-dependent plasticity were not considered; 2) extracted mantle melts were 100% transformed into volcanic rocks, whereas on the present day Earth only about 20-30% are volcanic and the remainder is plutonic; 3) the effect of a free surface was not studied in a systematic manner. In order to better understand how these simplifications affect the geodynamic models, we here present additional simulations to study the effects of each of these parameters. Johnson, T.E., Brown, M., Kaus, B., and VanTongeren, J.A., 2014, Delamination and recycling of Archaean crust caused by gravitational instabilities: Nature Geoscience, v. 7, no. 1, p. 47-52, doi: 10.1038/NGEO2019.

  12. Effects of simulated rare earth recycling wastewaters on biological nitrification

    DOE PAGES

    Fujita, Yoshiko; Barnes, Joni; Eslamimanesh, Ali; ...

    2015-07-16

    Current efforts to increase domestic availability of rare-earth element (REE) supplies by recycling and expanded ore processing efforts will result in increased generation of associated wastewaters. In some cases disposal to a sewage treatment plant may be favored but plant performance must be maintained. To assess the potential effects of such wastewaters on biological wastewater treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50 and 100 ppm), and the REE extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions above 10 ppm inhibited N.more » europaea activity, even when initially virtually all of the REE was insoluble. The provision of TBP together with Eu increased inhibition of nitrite production by the N. europaea, although TBP alone did not substantially alter nitrifying activity N. winogradskyi was more sensitive to the stimulated wastewaters, with even 10 ppm Eu or Y inducing significant inhibition, and a complete shutdown of nitrifying activity occurred in the presence of the TBP. To analyze the availability of REEs in aqueous solutions, REE solubility has been calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, which is typically controlled by the precipitation of REE hydroxides but may also be influenced by the formation of a phosphate phase.« less

  13. Effects of simulated rare earth recycling wastewaters on biological nitrification

    SciTech Connect

    Fujita, Yoshiko; Barnes, Joni; Eslamimanesh, Ali; Lencka, Malgorzata M.; Anderko, Andrzej; Riman, Richard E.; Navrotsky, Alexandra

    2015-07-16

    Current efforts to increase domestic availability of rare-earth element (REE) supplies by recycling and expanded ore processing efforts will result in increased generation of associated wastewaters. In some cases disposal to a sewage treatment plant may be favored but plant performance must be maintained. To assess the potential effects of such wastewaters on biological wastewater treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50 and 100 ppm), and the REE extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions above 10 ppm inhibited N. europaea activity, even when initially virtually all of the REE was insoluble. The provision of TBP together with Eu increased inhibition of nitrite production by the N. europaea, although TBP alone did not substantially alter nitrifying activity N. winogradskyi was more sensitive to the stimulated wastewaters, with even 10 ppm Eu or Y inducing significant inhibition, and a complete shutdown of nitrifying activity occurred in the presence of the TBP. To analyze the availability of REEs in aqueous solutions, REE solubility has been calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, which is typically controlled by the precipitation of REE hydroxides but may also be influenced by the formation of a phosphate phase.

  14. Satellite Motion Effects on Current Collection in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Zhang, T. X.; Hwang, K. S.; Wu, S. T.; Stone, N. H.; Chang, C. L.; Drobot, A.; Wright, K. H., Jr.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Results from the Tethered Satellite System (TSS) missions unambiguously show that the electrodynamic tether system produced 2 to 3 times the predicted current levels in the tether. The pre-mission predictions were based on the well-known Parker-Murphy (PM) model, which describes the collection of current by an electrically biased satellite in the ionospheric plasma. How the TSS satellite was able to collect 2-3 times the PM current has remained an open question. In the present study, self-consistent potential and motional effects are introduced into the Thompson and Dobrowolny sheath models. As a result, the magnetic field aligned sheath-an essential variable in determining current collection by a satellite-is derived and is shown to be explicitly velocity dependent. The orientation of the satellite's orbital motion relative to the geomagnetic field is also considered in the derivation and a velocity dependent expression for the collected current is obtained. The resulting model provides a realistic treatment of current collection by a satellite in low earth orbit. Moreover, the predictions, using the appropriate parameters for TSS, are in good agreement with the tether currents measured during the TSS-1R mission.

  15. Effects of Simulated Rare Earth Recycling Wastewaters on Biological Nitrification.

    PubMed

    Fujita, Yoshiko; Barnes, Joni; Eslamimanesh, Ali; Lencka, Malgorzata M; Anderko, Andrzej; Riman, Richard E; Navrotsky, Alexandra

    2015-08-18

    Increasing rare earth element (REE) supplies by recycling and expanded ore processing will result in generation of new wastewaters. In some cases, disposal to a sewage treatment plant may be favored, but plant performance must be maintained. To assess the potential effects of such wastewaters on biological treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50, and 100 ppm), and the extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions at 50 and 100 ppm inhibited N. europaea, even when virtually all of the REE was insoluble. Provision of TBP with Eu increased N. europaea inhibition, although TBP alone did not substantially alter activity. For N. winogradskyi cultures, Eu or Y additions at all tested levels induced significant inhibition, and nitrification shut down completely with TBP addition. REE solubility was calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, typically controlled by the precipitation of REE hydroxides but also likely affected by the formation of unknown phosphate phases, which determined aqueous concentrations experienced by the microorganisms.

  16. Observations and Effects of Dipolarization Fronts Observed in Earth's Magnetotail

    NASA Technical Reports Server (NTRS)

    Goldstein, Melvyn L.

    2011-01-01

    Dipolarization fronts in Earth's magnetotail are characterized by sharp jumps in magnetic field, a drop in density, and often follow earthward fast plasma flow. They are commonly detected near the equatorial plane of Earth s tail plasma sheet. Sometimes, but not always, dipolarization fronts are associated with global substorms and auroral brightenings. Both Cluster, THEMIS, and other spacecraft have detected dipolarization fronts in a variety of locations in the magnetotail. Using multi-spacecraft analyses together with simulations, we have investigated the propagation and evolution of some dipolarization events. We have also investigated the acceleration of electrons and ions that results from such magnetic-field changes. In some situations, the velocities of fast earthward flows are comparable to the Alfven speed, indicating that the flow bursts might have been generated by bursty reconnection that occurred tailward of the spacecraft. Based on multi-spacecraft timing analysis, dipolarization fronts are found to propagate mainly earthward at 160-335 km/s and have thicknesses of 900-1500 km, which corresponds to the ion inertial length or gyroradius scale. Following the passage of dipolarization fronts, significant fluctuations are observed in the x and y components of the magnetic field. These peaks in the magnetic field come approximately 1-2 minutes after passage of the dipolarization front. These Bx and By fluctuations propagate primarily dawnward and earthward. Field-aligned electron beams are observed coincident with those magnetic field fluctuations. Non-Maxwellian electron and ion distributions are observed that are associated with the dipolarization that may be unstable to a range of electrostatic and/or whistler instabilities. Enhanced electrostatic broadband noise at frequencies below and near the lower-hybrid frequency is also observed at or very close to these fronts. This broadband noise is thought to play a role in further energizing the particles

  17. Effects of Low Earth Orbit on Docking Seal Materials

    NASA Technical Reports Server (NTRS)

    Imka, Emily C.; Asmar, Olivia C.; deGroh, Henry C., III; Banks, Bruce A.

    2014-01-01

    Spacecraft docking seals are typically made of silicone elastomers. When such seals are exposed to low Earth orbit (LEO) conditions, they can suffer damage from ultraviolet (UV) radiation and atomic oxygen (AO, or monoatomic oxygen, the predominant oxygen species in LEO). An experiment flew on the International Space Station (ISS) to measure the effects of LEO on seal materials S0383-70 and ELA-SA-401 and various mating counterface materials which included anodized aluminum. Samples flown in different orientations received different amounts of UV and AO. The hypotheses were that most of the damage would be from UV, and 10 days or more of exposure in LEO would badly damage the seals. Eighteen seals were exposed for 543 days in ram (windward), zenith (away from Earth), or wake (leeward) orientations, and 15 control samples (not flown) provided undamaged baseline leakage. To determine post-flight leak rates, each of the 33 seals were placed in an O-ring groove of a leak test fixture and pressure tested over time. Resistance temperature detectors (RTDs), pressure transducers, and LabVIEW (National Instruments) programs were used to measure and analyze the temperature and pressure and calculate leakage. Average leakage of control samples was 2.6 x 10(exp -7) lbs/day. LEO exposure did not considerably damage ELA-SA-401. The S0383-70 flight samples leaked at least 10 times more than ELA-SA-401 in all cases except one, demonstrating that ELA-SA-401 may be a more suitable sealing material in LEO. AO caused greater damage than UV; samples in ram orientation (receiving an AO fluence of 4.3 x 10(exp 21) atoms/(sq cm) and in wake (2.9x 10(exp 20) atoms/(sq cm)) leaked more than those in zenith orientation (1.58 x 10(exp 20) atoms/(sq cm)), whereas variations in UV exposure did not seem to affect the samples. Exposure to LEO did less damage to the seals than hypothesized, and the data did not support the conjecture that UV causes more damage than AO.

  18. Comparison of relativistic effects in barycentric and Earth-centered coordinates and implications for determination of GM for Earth

    NASA Technical Reports Server (NTRS)

    Ashby, Neil

    1987-01-01

    The results of an investigation of relativistic effects which have an influence on the determination of GM sub E (M sub E is the mass of the Earth, G is the Newtonian gravitaional constant) are summarized. The detailed arguments and derivations are discussed. The Parametrized Post-Newtonian (PPN) coordinates; Eddington-Clark (EC) coordinates; a coordinate system based on barycentric dynamical time (TBC coordinates); and Local Inertial coordinates are discussed.

  19. From Order to Chaos in Earth Satellite Orbits

    NASA Astrophysics Data System (ADS)

    Gkolias, Ioannis; Daquin, Jérôme; Gachet, Fabien; Rosengren, Aaron J.

    2016-11-01

    We consider Earth satellite orbits in the range of semimajor axes where the perturbing effects of Earth’s oblateness and lunisolar gravity are of comparable order. This range covers the medium-Earth orbits (MEO) of the Global Navigation Satellite Systems and the geosynchronous orbits (GEO) of the communication satellites. We recall a secular and quadrupolar model, based on the Milankovitch vector formulation of perturbation theory, which governs the long-term orbital evolution subject to the predominant gravitational interactions. We study the global dynamics of this two-and-a-half degrees-of-freedom Hamiltonian system by means of the fast Lyapunov indicator (FLI), used in a statistical sense. Specifically, we characterize the degree of chaoticity of the action space using angle-averaged normalized FLI maps, thereby overcoming the angle dependencies of the conventional stability maps. Emphasis is placed upon the phase-space structures near secular resonances, which are of primary importance to the space debris community. We confirm and quantify the transition from order to chaos in MEO, stemming from the critical inclinations and find that highly inclined GEO orbits are particularly unstable. Despite their reputed normality, Earth satellite orbits can possess an extraordinarily rich spectrum of dynamical behaviors and, from a mathematical perspective, have all the complications that make them very interesting candidates for testing the modern tools of chaos theory.

  20. Atmospheric attenuation relative to earth-viewing orbital sensors. [atmospheric moisture effects on microwaves

    NASA Technical Reports Server (NTRS)

    Brown, S. C.; Jayroe, R. R., Jr.

    1973-01-01

    Earth viewing space missions offer exciting new possibilities in several earth resources disciplines - geography, hydrology, agriculture, geology, and oceanography, to name a few. A most useful tool in planning experiments and applying space technology to earth observation is a statistical description of atmospheric parameters. Four dimensional atmospheric models and a world wide cloud model are used to produce atmospheric attenuation models to predict degradation effects for all classes of sensors for application to earth sensing experiments from spaceborne platforms. To insure maximum utility and application of these products, the development of an interaction model of microwave energy and atmospheric variables provides a complete description of the effects of atmospheric moisture upon microwaves.

  1. The Effect of the Earth's Atmosphere on LSST Photometry

    SciTech Connect

    Rahlin, Alexandra S.; /MIT /SLAC

    2006-08-30

    The Large Synoptic Survey Telescope (LSST), a ground-based telescope currently under development, will allow a thorough study of dark energy by measuring, more completely and accurately than previously, the rate of expansion of the universe and the large-scale structure of the matter in it. The telescope utilizes a broadband photometric system of six wavelength bands to measure the redshifts of distant objects. The earth's atmosphere makes it difficult to acquire accurate data, since some of the light passing through the atmosphere is scattered or absorbed due to Rayleigh scattering, molecular absorption, and aerosol scattering. Changes in the atmospheric extinction distribution due to each of these three processes were simulated by altering the parameters of a sample atmospheric distribution. Spectral energy distributions of standard stars were used to simulate data acquired by the telescope. The effects of changes in the atmospheric parameters on the photon flux measurements through each wavelength band were observed in order to determine which atmospheric conditions must be monitored most closely to achieve the desired 1% uncertainty on flux values. It was found that changes in the Rayleigh scattering parameter produced the most significant variations in the data; therefore, the molecular volume density (pressure) must be measured with at most 8% uncertainty. The molecular absorption parameters produced less significant variations and could be measured with at most 62% uncertainty. The aerosol scattering parameters produced almost negligible variations in the data and could be measured with > 100% uncertainty. These atmospheric effects were found to be almost independent of the redshift of the light source. The results of this study will aid the design of the atmospheric monitoring systems for the LSST.

  2. Unusual locations of Earth`s bow shock on September 24-25, 1987: Mach number effects

    SciTech Connect

    Cairns, I.H.; Anderson, R.R.; Fairfield, D.H.; Carlton, V.E.H.; Paularena, K.I.; Lazarus, A.J.

    1995-01-01

    ISEE 1 and IMP 8 data are used to identify 19 crossings of Earth`s bow shock during a 30-hour period following 0000 UT on September 24, 1987. Apparent standoff distances for the shock are calculated for each crossing using two methods and the spacecraft location; one method assumes the average shock shape, while the other assumes a ram pressure-dependent shock shape. The shock`s apparent standoff distance normally {approximately}14 R{sub E}, is shown to increase from near 10 R{sub E} initially to near 19 R{sub E}. The Alfven M{sub A} and fast magnetosonic M{sub ms} Mach numbers remain above 2 and the number density above 4 cm{sup {minus}3} for almost the entire period. Ram pressure effects produce the initial near-Earth shock location, whereas expansions and contractions of the bow shock due to low Mach number effects account, qualitatively and semiquantitatively, for the timing and existence of almost all the remaining ISEE crossings and both IMP 8 crossings. Ram pressure-induced changes in the shock`s shape are discussed but found to be quantitatively unimportant for the shock crossings analyzed. Approximate estimates of both the deviation of the shock`s standoff distance from the standard model and of the shock`s shape are determined independently (but not consistently) for M{sub ms}{approximately}2.4. The estimates imply substantial changes in standoff distance and/or shock shape at low M{sub A} and M{sub ms}. Mach number effects can therefore be quantitatively important in determining and predicting the shape and location of the bow shock, even when M{sub A} and M{sub ms} remain above 2. This study confirms and generalizes previous studies of Mach number effects on Earth`s bow shock. Statistical studies and simulations of the bow shock`s shape and location should be performed as a function of Mach number, magnetic field orientation, and ram pressure. 25 refs., 12 figs.

  3. Solar rotation effects on the thermospheres of Mars and Earth.

    PubMed

    Forbes, Jeffrey M; Bruinsma, Sean; Lemoine, Frank G

    2006-06-02

    The responses of Earth's and Mars' thermospheres to the quasi-periodic (27-day) variation of solar flux due to solar rotation were measured contemporaneously, revealing that this response is twice as large for Earth as for Mars. Per typical 20-unit change in 10.7-centimeter radio flux (used as a proxy for extreme ultraviolet flux) reaching each planet, we found temperature changes of 42.0 +/- 8.0 kelvin and 19.2 +/- 3.6 kelvin for Earth and Mars, respectively. Existing data for Venus indicate values of 3.6 +/- 0.6 kelvin. Our observational result constrains comparative planetary thermosphere simulations and may help resolve existing uncertainties in thermal balance processes, particularly CO2 cooling.

  4. Second-order quadrupolar line shapes under molecular dynamics: An additional transition in the extremely fast regime.

    PubMed

    Hung, Ivan; Wu, Gang; Gan, Zhehong

    2016-12-10

    NMR spectroscopy is a powerful tool for probing molecular dynamics. For the classic case of two-site exchange, NMR spectra go through the transition from exchange broadening through coalescence and then motional narrowing as the exchange rate increases passing through the difference between the resonance frequencies of the two sites. For central-transition spectra of half-integer quadrupolar nuclei in solids, line shape change due to molecular dynamics occurs in two stages. The first stage occurs when the exchange rate is comparable to the second-order quadrupolar interaction. The second spectral transition comes at a faster exchange rate which approaches the Larmor frequency and generally reduces the isotropic quadrupolar shift. Such a two-stage transition phenomenon is unique to half-integer quadrupolar nuclei. A quantum mechanical formalism in full Liouville space is presented to explain the physical origin of the two-stage phenomenon and for use in spectral simulations. Variable-temperature (17)O NMR of solid NaNO3 in which the NO3(-) ion undergoes 3-fold jumps confirms the two-stage transition process. The spectra of NaNO3 acquired in the temperature range of 173-413K agree well with simulations using the quantum mechanical formalism. The rate constants for the 3-fold NO3(-) ion jumps span eight orders of magnitude (10(2)-10(10)s(-1)) covering both transitions of the dynamic (17)O line shape.

  5. Static quadrupolar susceptibility for a Blume-Emery-Griffiths model based on the mean-field approximation

    NASA Astrophysics Data System (ADS)

    Pawlak, A.; Gülpınar, G.; Erdem, R.; Ağartıoğlu, M.

    2015-12-01

    The expressions for the dipolar and quadrupolar susceptibilities are obtained within the mean-field approximation in the Blume-Emery-Griffiths model. Temperature as well as crystal field dependences of the susceptibilities are investigated for two different phase diagram topologies which take place for K/J=3 and K/J=5.0.Their behavior near the second and first order transition points as well as multi-critical points such as tricritical, triple and critical endpoint is presented. It is found that in addition to the jumps connected with the phase transitions there are broad peaks in the quadrupolar susceptibility. It is indicated that these broad peaks lie on a prolongation of the first-order line from a triple point to a critical point ending the line of first-order transitions between two distinct paramagnetic phases. It is argued that the broad peaks are a reminiscence of very strong quadrupolar fluctuations at the critical point. The results reveal the fact that near ferromagnetic-paramagnetic phase transitions the quadrupolar susceptibility generally shows a jump whereas near the phase transition between two distinct paramagnetic phases it is an edge-like.

  6. The effect of aerosols on the earth-atmosphere albedo

    NASA Technical Reports Server (NTRS)

    Herman, B. M.; Browning, S. R.

    1975-01-01

    The paper presents calculations of the change in reflected flux by the earth-atmosphere system in response to increases in the atmospheric aerosol loading for a range of complex indices of refraction, solar elevation angle and ground albedo. Results show that, for small values of ground albedo, the reflected solar flux may either increase or decrease with increasing aerosol loadings, depending upon the complex part of the index of refraction of the aerosols. For high ground albedos, an increase in aerosol levels always results in a decrease of reflected flux (i.e., a warming of the earth-atmosphere system).

  7. COLORS OF A SECOND EARTH. II. EFFECTS OF CLOUDS ON PHOTOMETRIC CHARACTERIZATION OF EARTH-LIKE EXOPLANETS

    SciTech Connect

    Fujii, Yuka; Suto, Yasushi; Turner, Edwin L.; Kawahara, Hajime; Fukuda, Satoru; Nakajima, Teruyuki; Livengood, Timothy A.

    2011-09-10

    As a test bed for future investigations of directly imaged terrestrial exoplanets, we present the recovery of the surface components of the Earth from multi-band diurnal light curves obtained with the EPOXI spacecraft. We find that the presence and longitudinal distribution of ocean, soil, and vegetation are reasonably well reproduced by fitting the observed color variations with a simplified model composed of a priori known albedo spectra of ocean, soil, vegetation, snow, and clouds. The effect of atmosphere, including clouds, on light scattered from surface components is modeled using a radiative transfer code. The required noise levels for future observations of exoplanets are also determined. Our model-dependent approach allows us to infer the presence of major elements of the planet (in the case of the Earth, clouds, and ocean) with observations having signal-to-noise ratio (S/N) {approx}> 10 in most cases and with high confidence if S/N {approx}> 20. In addition, S/N {approx}> 100 enables us to detect the presence of components other than ocean and clouds in a fairly model-independent way. Degradation of our inversion procedure produced by cloud cover is also quantified. While cloud cover significantly dilutes the magnitude of color variations compared with the cloudless case, the pattern of color changes remains. Therefore, the possibility of investigating surface features through light-curve fitting remains even for exoplanets with cloud cover similar to Earth's.

  8. Best Mitigation Paths To Effectively Reduce Earth's Orbital Debris

    NASA Technical Reports Server (NTRS)

    Wiegman, Bruce M.

    2009-01-01

    This slide presentation reviews some ways to reduce the problem posed by debris in orbit around the Earth. It reviews the orbital debris environment, the near-term needs to minimize the Kessler syndrome, also known as collisional cascading, a survey of active orbital debris mitigation strategies, the best paths to actively remove orbital debris, and technologies that are required for active debris mitigation.

  9. Implementing SPAM into STMAS: A net sensitivity improvement in high-resolution NMR of quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Amoureux, J. P.; Delevoye, L.; Fink, G.; Taulelle, F.; Flambard, A.; Montagne, L.

    2005-08-01

    Gan and Kwak recently introduced two new tools for high-resolution 2D NMR methods applied to quadrupolar nuclei: double-quantum filtering in STMAS (DQF-STMAS) and the soft-pulse added mixing (SPAM) idea. Double-quantum filtering suppresses all undesired signals in the STMAS method with limited loss in sensitivity. With SPAM, all pathways are added constructively after the second hard-pulse instead of using a single pathway as previously. Here, the sensitivity, advantages and drawbacks of DQF-STMAS are compared to 3QMAS. Additionally, SPAM can be included into DQF-STMAS method, resulting in a net sensitivity gain with respect to 3QMAS of ca. 10-15.

  10. Implementing SPAM into STMAS: a net sensitivity improvement in high-resolution NMR of quadrupolar nuclei.

    PubMed

    Amoureux, J P; Delevoye, L; Fink, G; Taulelle, F; Flambard, A; Montagne, L

    2005-08-01

    Gan and Kwak recently introduced two new tools for high-resolution 2D NMR methods applied to quadrupolar nuclei: double-quantum filtering in STMAS (DQF-STMAS) and the soft-pulse added mixing (SPAM) idea. Double-quantum filtering suppresses all undesired signals in the STMAS method with limited loss in sensitivity. With SPAM, all pathways are added constructively after the second hard-pulse instead of using a single pathway as previously. Here, the sensitivity, advantages and drawbacks of DQF-STMAS are compared to 3QMAS. Additionally, SPAM can be included into DQF-STMAS method, resulting in a net sensitivity gain with respect to 3QMAS of ca. 10-15.

  11. From bipolar to quadrupolar - The collimation processes of the Cepheus A outflow

    NASA Technical Reports Server (NTRS)

    Torrelles, Jose M.; Verdes-Montenegro, Lourdes; Ho, Paul T. P.; Rodriguez, Luis F.; Canto, Jorge

    1993-01-01

    Results of new K-band observations of the (1, 1) and (2, 2) ammonia lines toward Cepheus A are reported. The lines are mapped with approximately 2 arcsec of angular resolution and 0.3 km/s of velocity resolution. A sensitivity of 10 mJy has been achieved. The observations reveal details of the spatial and kinematics structure of the ambient high-density gas. It is suggested that the interstellar high-density gas is diverting and redirecting the outflow in the sense that the quadrupolar structure of the molecular outflow is produced by the interaction with the ammonia condensationss, with Cep A-1 and Cep A-3 splitting in two halves, respectively the blue- and redshifted lobes of an east-west bipolar molecular outflow.

  12. Pulmonary MRI contrast using Surface Quadrupolar Relaxation (SQUARE) of hyperpolarized (83)Kr.

    PubMed

    Six, Joseph S; Hughes-Riley, Theodore; Lilburn, David M L; Dorkes, Alan C; Stupic, Karl F; Shaw, Dominick E; Morris, Peter G; Hall, Ian P; Pavlovskaya, Galina E; Meersmann, Thomas

    2014-01-01

    Hyperpolarized (83)Kr has previously been demonstrated to enable MRI contrast that is sensitive to the chemical composition of the surface in a porous model system. Methodological advances have lead to a substantial increase in the (83)Kr hyperpolarization and the resulting signal intensity. Using the improved methodology for spin exchange optical pumping of isotopically enriched (83)Kr, internal anatomical details of ex vivo rodent lung were resolved with hyperpolarized (83)Kr MRI after krypton inhalation. Different (83)Kr relaxation times were found between the main bronchi and the parenchymal regions in ex vivo rat lungs. The T1 weighted hyperpolarized (83)Kr MRI provided a first demonstration of surface quadrupolar relaxation (SQUARE) pulmonary MRI contrast.

  13. Tidal effects on Earth, Planets, Sun by far visiting moons

    NASA Astrophysics Data System (ADS)

    Fargion, Daniele

    2016-07-01

    The Earth has been formed by a huge mini-planet collision forming our Earth surface and our Moon today. Such a central collision hit was statistically rare. A much probable skimming or nearby encounter by other moons or planets had to occur. Indeed Recent observations suggest that many planetary-mass objects may be present in the outer solar system between the Kuiper belt and the Oort cloud. Gravitational perturbations may occasionally bring them into the inner solar system. Their passage near Earth could have generated gigantic tidal waves, large volcanic eruptions, sea regressions, large meteoritic impacts and drastic changes in global climate. They could have caused the major biological mass extinctions in the past in the geological records. For instance a ten times a terrestrial radius nearby impact scattering by a peripherical encounter by a small moon-like object will force huge tidal waves (hundred meter height), able to lead to huge tsunami and Earth-quake. Moreover the historical cumulative planet hits in larger and wider planets as Juppiter, Saturn, Uranus will leave a trace, as observed, in their tilted spin axis. Finally a large fraction of counter rotating moons in our solar system probe and test such a visiting mini-planet captur origination. In addition the Earth day duration variability in the early past did show a rare discountinuity, very probably indebt to such a visiting planet crossing event. These far planets in rare trajectory to our Sun may, in thousands event capture, also explain sudden historical and recent temperature changes.

  14. The Impenetrable Barrier Revisited - Anthroprogenic Effects on Earth's Radiation Belts

    NASA Astrophysics Data System (ADS)

    Foster, J. C.; Baker, D. N.; Erickson, P. J.; Albert, J.; Fennell, J. F.; Mishin, E. V.; Starks, M. J.; Jaynes, A. N.; Li, X.; Kanekal, S. G.; Kletzing, C.

    2015-12-01

    The Van Allen Probes are contributing significantly to the understanding of processes effecting Earth's radiation belts. It has been noted that the earthward extent of the outer zone highly-relativistic electrons encounters a nearly impenetrable barrier at a radial distance (L) near 2.8 RE inside of which they are not observed. Modeling suggests that this is the result of a balance between slow inward diffusion and hiss-induced precipitation. The large storm of 17 March 2015 afforded an excellent opportunity to investigate the impenetrable barrier using the full complement of sensors carried by the Van Allen Probes. The storm was marked by the rapid reappearance of strong fluxes of MeV electrons directly outside the barrier with the formation of very steep MeV flux gradients. In spite of the strong rapid recovery of MeV electron fluxes immediately outside the barrier, the sharpness and constancy of the gradient at the barrier is strongly suggestive of a previously unrecognized fast-acting and spatially localized mechanism responsible for the formation of such a well-defined feature during these dramatic circumstances. The Van Allen Probes regularly observe a magnetically confined bubble of VLF emissions of terrestrial origin filling the inner magnetosphere. Strongest signals are from US Navy VLF transmitters used for one-way communication to submarines. These signals largely are confined to the region of L space where their frequency is < ½ fce. The strong signal from station NAA at 24 kHz is confined to L < 2.8 where it encounters the ½ fce limit. During the event, the flux of MeV electrons decreased by 1000x across 0.5 RE outside L = 2.8 simultaneous with a 6 order of magnitude increase in the VLF wave intensity as the Probes entered the VLF bubble. The VLF transmitter frequencies are amplified at the point where they overlap natural chorus band near ½ fce suggestive of transmitter-induced triggered emissions. MeV radiation belt electrons encounter this

  15. Analysis of earth albedo effect on sun sensor measurements based on theoretical model and mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, Dan; Sedlak, Joseph

    1998-01-01

    Analysis of flight data from previous missions indicates that anomalous Sun sensor readings could be caused by Earth albedo interference. A previous Sun sensor study presented a detailed mathematical model of this effect. The model can be used to study the effect of both diffusive and specular reflections and to improve Sun angle determination based on perturbed Sun sensor measurements, satellite position, and an approximate knowledge of attitude. The model predicts that diffuse reflected light can cause errors of up to 10 degrees in Coarse Sun Sensor (CSS) measurements and 5 to 10 arc sec in Fine Sun Sensor (FSS) measurements, depending on spacecraft orbit and attitude. The accuracy of these sensors is affected as long as part of the illuminated Earth surface is present in the sensor field of view. Digital Sun Sensors (DSS) respond in a different manner to the Earth albedo interference. Most of the time DSS measurements are not affected, but for brief periods of time the Earth albedo can cause errors which are a multiple of the sensor least significant bit and may exceed one degree. This paper compares model predictions with Tropical Rainfall Measuring Mission (TRMM) CSS measurements in order to validate and refine the model. Methods of reducing and mitigating the impact of Earth albedo are discussed. ne CSS sensor errors are roughly proportional to the Earth albedo coefficient. Photocells that are sensitive only to ultraviolet emissions would reduce the effective Earth albedo by up to a thousand times, virtually eliminating all errors caused by Earth albedo interference.

  16. Effects of Superthermal Electrons in The Young Earth Atmosphere and Its Habitability

    NASA Astrophysics Data System (ADS)

    Airapetian, V.; Khazanov, G. V.

    2014-12-01

    In this presentation, we use the Fokker-Plank code to model the effect of intensive short-wavelength (X-rays to UV band) emission from the young Sun on Earth's atmosphere. Our simulations include the photoionization processes of the Earth's atmosphere forming a population of superthermal electrons (E<600 eV), the kinetic effects of their propagation associated and their contribution in ionosphere-magnetosphere energy redistribution. We also evaluated associated non-thermal atmospheric mass loss due to induced ambipolar electric field and its effect on the habitability of early Earth.

  17. The Effect of Fulvic Acid on the Leaching of a Weathered Rare-Earth Ore

    NASA Astrophysics Data System (ADS)

    Luo, Xian-ping; Feng, Bo; Wang, Peng-cheng; Zhou, He-peng; Chen, Xiao-ming

    2015-12-01

    The effect of fulvic acid on the leaching of a weathered crust elution-deposited rare-earth ore, using ammonium sulfate as lixiviant, has been investigated. The results show that fulvic acid can enhance the leaching process effectively. With the addition of fulvic acid to the lixiviant at a concentration of 0.1 wt pct, the leaching extraction of rare-earth elements increased by 8.38 pct and the ammonium sulfate concentration decreased by 25 wt pct. Fulvic acid promotes the leaching process. It also reacts with rare-earth ions, forms soluble complexes, reduces the activity of the leached rare-earth ions, and increases the concentration difference of ion diffusion. These results highlight a new approach for making the leaching process of low-grade weathered crust elution-deposited rare-earth ore more efficient and also for lowering the lixiviant consumption.

  18. The effect of the earth's rotation on ground water motion.

    PubMed

    Loáiciga, Hugo A

    2007-01-01

    The average pore velocity of ground water according to Darcy's law is a function of the fluid pressure gradient and the gravitational force (per unit volume of ground water) and of aquifer properties. There is also an acceleration exerted on ground water that arises from the Earth's rotation. The magnitude and direction of this rotation-induced force are determined in exact mathematical form in this article. It is calculated that the gravitational force is at least 300 times larger than the largest rotation-induced force anywhere on Earth, the latter force being maximal along the equator and approximately equal to 34 N/m(3) there. This compares with a gravitational force of approximately 10(4) N/m(3).

  19. Single Event Effects Testing For Low Earth Orbit Missions with Neutrons

    NASA Technical Reports Server (NTRS)

    Reddell, Brandon; O'Neill, Pat; Bailey, Chuck; Nguyen, Kyson

    2015-01-01

    Neutrons can effectively be used to screen electronic parts intended to be used in Low Earth Orbit. This paper compares neutron with proton environments in spacecraft and discusses recent comparison testing.

  20. Telluric currents have no significant effect on the Earth's core seismicity

    NASA Astrophysics Data System (ADS)

    Chernogor, L. F.

    2017-01-01

    We show that telluric currents have no effect on the formation of macrofaults in the Earth's crust or on implementation of the intensification regime. This is mainly associated with the weakness of telluric currents and induction of the geomagnetic field.

  1. Study of effects of space power satellites on life support functions of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Douglas, M.; Laquey, R.; Deforest, S. E.; Lindsey, C.; Warshaw, H.

    1977-01-01

    The effects of the Satellite Solar Power System (SSPS) on the life support functions of the earth's magnetosphere were investigated. Topics considered include: (1) thruster effluent effects on the magnetosphere; (2) biological consequences of SSPS reflected light; (3) impact on earth bound astronomy; (4) catastrophic failure and debris; (5) satellite induced processes; and (6) microwave power transmission. Several impacts are identified and recommendations for further studies are provided.

  2. An Assessment of Relativistic Effects for Low Earth Orbiters: The GRACE Satellites

    DTIC Science & Technology

    2007-01-01

    IOP PUBLISHING METROLOGIA Metrologia 44 (2007) 484–490 doi:10.1088/0026-1394/44/6/007 An assessment of relativistic effects for low Earth orbiters...for the larger-eccentricity orbit is shown in figure 2(b). Metrologia , 44 (2007) 484–490 485 K M Larson et al Figure 1. Amplitude of the once/rev...486 Metrologia , 44 (2007) 484–490 Assessment of relativistic effects for low Earth orbiters combination was launched on TOPEX in 1992. Unfortunately

  3. The effect of EarthPulse on learning of declarative knowledge

    NASA Astrophysics Data System (ADS)

    McKinney, Heather E.

    The purpose of this double-blind, bio-medical research study was to investigate the effect of EarthPulse, a brainwave entrainment and pulsed electromagnetic field (PEMF) device, on learning of declarative knowledge. Currently, PEMF research explores physiological and psychological effects but a gap exists in the potential effects of PEMF on learning. The study explored whether a relationship existed between receiving a thirty minute EarthPulse treatment on the "Entrain Up" setting and learning of declarative knowledge; whether the relationship remained over time; whether EarthPulse had an effect on sleep; and whether EarthPulse had an effect on attrition. Ninety-eight, randomly assigned, undergraduate students participated in this double-blind, experimental design study, of which 87 remained after attrition. After receiving a thirty minute EarthPulse or placebo treatment, experimental and control groups read identical passages and completed identical instruments to test learning and retention of declarative knowledge. Participants completed the same test in two intervals: an immediate (learning) and delayed (retention) posttest. Assumptions for normality and reliability were met. One-way ANOVA revealed no statistically significant effects on learning or retention at the 0.05 level. However, Chi square analysis revealed those who received the EarthPulse treatment were significantly less likely to fall asleep than those who received the control treatment (p=0.022) and very closely approached significance for attrition (p=0.051).

  4. Q.E.COSY: determining sign and size of small deuterium residual quadrupolar couplings using an extended E.COSY principle.

    PubMed

    Tzvetkova, Pavleta; Luy, Burkhard

    2016-05-01

    Residual quadrupolar couplings contain important structural information comparable with residual dipolar couplings. However, the measurement of sign and size of especially small residual quadrupolar couplings is difficult. Here, we present an extension of the E.COSY principle to spin systems consisting of a Spin 1 coupled to a spin ½ nucleus, which allows the determination of the sign of the quadrupolar coupling of the Spin 1 nucleus relative to the heteronuclear coupling between the spins. The so-called Q.E.COSY approach is demonstrated with its sign-sensitivity using variable angle NMR, stretched gels and liquid crystalline phases applied to various CD and CD3 groups. Especially the sign-sensitive measurement of residual quadrupolar couplings that remain unresolved in conventional deuterium 1D spectra is shown.

  5. The Effect of Rare Earth on the Structure and Performance of Laser Clad Coatings

    NASA Astrophysics Data System (ADS)

    Bao, Ruiliang; Yu, Huijun; Chen, Chuanzhong; Dong, Qing

    Laser cladding is one kind of advanced surface modification technology and has the abroad prospect in making the wear-resistant coating on metal substrates. However, the application of laser cladding technology does not achieve the people's expectation in the practical production because of many defects such as cracks, pores and so on. The addiction of rare earth can effectively reduce the number of cracks in the clad coating and enhance the coating wear-resistance. In the paper, the effects of rare earth on metallurgical quality, microstructure, phase structure and wear-resistance are analyzed in turns. The preliminary discussion is also carried out on the effect mechanism of rare earth. At last, the development tendency of rare earth in the laser cladding has been briefly elaborated.

  6. NMR of group 2 element quadrupolar nuclei and some applications in materials science and biology

    NASA Astrophysics Data System (ADS)

    Li, Xiaohua

    1999-11-01

    For many years, NMR has provided an easy access for chemists to perform structural and kinetic studies on a whole variety of systems. To a great extent, these investigations have been restricted to non-quadrupolar nuclei. The study of quadrupolar nuclei (I > 1/2) offers the potential to gain insight into important problems in material science and biology. In addition to the large quadrupole moment associated with the spin active nuclei of interest, several of the most interesting species also possess an extremely low natural abundance. My recent research focuses on 87Sr NMR, which has been cited by earlier workers as being limited to only ionic species. Several strontium-containing compounds have been synthesized and characterized by single crystal x-ray diffraction. 87Sr NMR signals were determined for these compounds in a series of aprotic polar solvents. The chemical shift variation was found to be consistent with linen free energy relationship, which can be very useful in helping to elucidate mechanism, in predicting reaction rates, and the extent of reaction at equilibrium, and in discovering under what conditions a change in mechanism occurs. Control over symmetry of the compound was found to be the key to obtain the good NMR signals. One application of the new technique that has been developed was in the area of material science. An observation relative to sol-gel derived ionic conductors (La0.8Sr0.2Co0.8Fe0.2O 3.2) was that films often formed cracks upon pyrolysis. By careful examination of the sol-gel process by 87Sr NMR, a model for the structure of the sol was developed. Through the relaxation rate study of the strontium sites, the polymerization mechanism was determined to be predominantly bimolecular within the concentration region studied. The kinetic study of the fast cation exchange between two strontium sites indicated that the inhomogeneity of the polymeric network lads to the film cracking during pyrolysis. As a consequence of understanding the

  7. Solid-state NMR spectroscopy of the quadrupolar halogens: chlorine-35/37, bromine-79/81, and iodine-127.

    PubMed

    Bryce, David L; Sward, Gregory D

    2006-04-01

    A thorough review of 35/37Cl, 79/81Br, and 127I solid-state nuclear magnetic resonance (SSNMR) data is presented. Isotropic chemical shifts (CS), quadrupolar coupling constants, and other available information on the magnitude and orientation of the CS and electric field gradient (EFG) tensors for chlorine, bromine, and iodine in diverse chemical compounds is tabulated on the basis of over 200 references. Our coverage is through July 2005. Special emphasis is placed on the information available from the study of powdered diamagnetic solids in high magnetic fields. Our survey indicates a recent notable increase in the number of applications of solid-state quadrupolar halogen NMR, particularly 35Cl NMR, as high magnetic fields have become more widely available to solid-state NMR spectroscopists. We conclude with an assessment of possible future directions for research involving 35/37Cl, 79/81Br, and 127I solid-state NMR spectroscopy.

  8. In vivo observation of quadrupolar splitting in (39)K magnetic resonance spectroscopy of human muscle tissue.

    PubMed

    Rösler, M B; Nagel, A M; Umathum, R; Bachert, P; Benkhedah, N

    2016-04-01

    The purpose of this work was to explore the origin of oscillations of the T(*)2 decay curve of (39)K observed in studies of (39)K magnetic resonance imaging of the human thigh. In addition to their magnetic dipole moment, spin-3/2 nuclei possess an electric quadrupole moment. Its interaction with non-vanishing electrical field gradients leads to oscillations in the free induction decay and to splitting of the resonance. All measurements were performed on a 7T whole-body MRI scanner (MAGNETOM 7T, Siemens AG, Erlangen, Germany) with customer-built coils. According to the theory of quadrupolar splitting, a model with three Lorentzian-shaped peaks is appropriate for (39)K NMR spectra of the thigh and calf. The frequency shifts of the satellites depend on the angle between the calf and the static magnetic field. When the leg is oriented parallel to the static magnetic field, the satellites are shifted by about 200 Hz. In the thigh, rank-2 double quantum coherences arising from anisotropic quadrupolar interaction are observed by double-quantum filtration with magic-angle excitation. In addition to the spectra, an image of the thigh with a nominal resolution of (16 × 16 × 32) mm(3) was acquired with this filtering technique in 1:17 h. From the line width of the resonances, (39)K transverse relaxation time constants T(*)2, fast  = (0.51 ± 0.01) ms and T(*)2, slow  = (6.21 ± 0.05) ms for the head were determined. In the thigh, the left and right satellite, both corresponding to the short component of the transverse relaxation time constant, take the following values: T(*)2, fast  = (1.56 ± 0.03) ms and T(*)2, fast  = (1.42 ± 0.03) ms. The centre line, which corresponds to the slow component, is T(*)2, slow  = (9.67 ± 0.04) ms. The acquisition time of the spectra was approximately 10 min. Our results agree well with a non-vanishing electrical field gradient interacting with (39)K nuclei in the intracellular space of

  9. 2H 2O quadrupolar splitting used to measure water exchange in erythrocytes

    NASA Astrophysics Data System (ADS)

    Kuchel, Philip W.; Naumann, Christoph

    2008-05-01

    The 2H NMR resonance from HDO (D = 2H) in human red blood cells (RBCs) suspended in gelatin that was held stretched in a special apparatus was distinct from the two signals that were symmetrically arranged on either side of it, which were assigned to extracellular HDO. The large extracellular splitting is due to the interaction of the electric quadrupole moment of the 2H nuclei with the electric field gradient tensor of the stretched, partially aligned gelatin. Lack of resolved splitting of the intracellular resonance indicated greatly diminished or absent ordering of the HDO inside RBCs. The separate resonances enabled the application of a saturation transfer method to estimate the rate constants of transmembrane exchange of water in RBCs. However both the theory and the practical applications needed modifications because even in the absence of RBCs the HDO resonances were maximally suppressed when the saturating radio-frequency radiation was applied exactly at the central frequency between the two resonances of the quadrupolar HDO doublet. More statistically robust estimates of the exchange rate constants were obtained by applying two-dimensional exchange spectroscopy (2D EXSY), with back-transformation analysis. A monotonic dependence of the estimates of the efflux rate constants on the mixing time, tmix, used in the 2D EXSY experiment were seen. Extrapolation to tmix = 0, gave an estimate of the efflux rate constant at 15 °C of 31.5 ± 2.2 s -1 while at 25 °C it was ˜50 s -1. These values are close to, but less than, those estimated by an NMR relaxation-enhancement method that uses Mn 2+ doping of the extracellular medium. The basis for this difference is thought to include the high viscosity of the extracellular gel. At the abstract level of quantum mechanics we have used the quadrupolar Hamiltonian to provide chemical shift separation between signals from spin populations across cell membranes; this is the first time, to our knowledge, that this has been

  10. Glacier Melting Effect on the Earth's Rotation - Revisited

    NASA Astrophysics Data System (ADS)

    Na, S. H.; Sahagian, D. L.; Kim, T. H.; Jo, B. G.; Ahn, K. D.; Shin, Y. H.

    2014-12-01

    The direction of polar wander has recently been tilted eastward by several degrees. By direct calculation of Earth's inertia tensor perturbation due to observed glacier mass changes (twenty year average), we found the yearly drift polar motion excitation as (ψ1, ψ2)=(1.00, 0.05) milliarcsec. This direction closely matches the observed pole drift, and we infer that glacier melting is the primary driver of the observed polar wander. Analysis of polar motion data indicates that a substantial portion of the observed eastward pole drift has occurred since the late 1990s, also consistent with the accelerated rate of glacier melting. The associated change in LOD due to average glacier melting for the last twenty years is estimated as +114 microsec, which implies total 0.42 s delay in UT1 for the same time span.

  11. Discover Earth

    NASA Technical Reports Server (NTRS)

    Steele, Colleen

    1998-01-01

    Discover Earth is a NASA-sponsored project for teachers of grades 5-12, designed to: (1) enhance understanding of the Earth as an integrated system; (2) enhance the interdisciplinary approach to science instruction; and (3) provide classroom materials that focus on those goals. Discover Earth is conducted by the Institute for Global Environmental Strategies in collaboration with Dr. Eric Barron, Director, Earth System Science Center, The Pennsylvania State University; and Dr. Robert Hudson, Chair, the Department of Meteorology, University of Maryland at College Park. The enclosed materials: (1) represent only part of the Discover Earth materials; (2) were developed by classroom teachers who are participating in the Discover Earth project; (3) utilize an investigative approach and on-line data; and (4) can be effectively adjusted to classrooms with greater/without technology access. The Discover Earth classroom materials focus on the Earth system and key issues of global climate change including topics such as the greenhouse effect, clouds and Earth's radiation balance, surface hydrology and land cover, and volcanoes and climate change. All the materials developed to date are available on line at (http://www.strategies.org) You are encouraged to submit comments and recommendations about these materials to the Discover Earth project manager, contact information is listed below. You are welcome to duplicate all these materials.

  12. Biological effects of high ultraviolet radiation on early earth--a theoretical evaluation.

    PubMed

    Cockell, C S

    1998-08-21

    The surface of early Earth was exposed to both UVC radiation (< 280 nm) and higher doses of UVB (280-315 nm) compared with the surface of present day Earth. The degree to which this radiation environment acted as a selection pressure on organisms and biological systems has rarely been theoretically examined with respect to the biologically effective irradiances that ancient organisms would receive. Here action spectra for DNA inactivation and isolated chloroplast inhibition are used to estimate biologically effective irradiances on archean Earth. Comparisons are made with present day Earth. The theoretical estimations on the UV radiation screening required to protect DNA on archean Earth compare well with field and laboratory observations on protection strategies found in present day microbial communities. They suggest that many physical and biological methods may have been effective and would have allowed for the radiation of life even under the high UV radiation regimes of archean Earth. Such strategies would also have provided effective reduction of photoinhibition by UV radiation. The data also suggest that the UV regime on the surface of Mars is not a life limiting factor per se, although other environmental factors such as desiccation and low temperatures may contribute towards the apparent lack of a surface biota.

  13. Resonant and static cubic hyperpolarizabilities of push-pull dipolar and quadrupolar chromophores: toward enhanced two-photon absorption

    NASA Astrophysics Data System (ADS)

    Barzoukas, Marguerite; Blanchard-Desce, Mireille H.

    2001-12-01

    Recent reports of push-pull dipolar and quadrupolar chromophores with enhanced two-photon absorption have generated considerable interest in these two molecular systems. Two photon absorption is related to the imaginary part of the two-photon resonant cubic hyperpolarizability Im[(gamma) ((omega) )]. In this work, we have described both push-pull dipolar and quadrupolar chromophores using multi valence-bond states models based on measurable parameters of the valence-bond forms. We have derived analytical expressions of their non-resonant static cubic hyperpolarizability (gamma) (0) and of Im[(gamma) ((omega) )]. Comparison between the transparency / Im[(gamma) ((omega) )] trade-off and Im[(gamma) ((omega) )] / (gamma) (0) correlation helps understand the advantages and drawbacks of each of these two push-pull systems. Furthermore by understanding how the valence-bond parameters are related to the molecular structure and its environment, it is possible to predict how Im[(gamma) ((omega) )] will be affected by changing either the conjugation size, the donor-acceptor pair or the solvent polarity for both of these push-pull systems. The results of this study suggest common guidelines for the molecular engineering of both the push-pull dipolar and quadrupolar chromophores.

  14. Effect of alkaline-earth ions on the dynamics of alkali ions in bismuthate glasses

    NASA Astrophysics Data System (ADS)

    Dutta, A.; Ghosh, A.

    2005-12-01

    The effect of alkaline earth ions on the dynamics of Li+ ions in bismuthate glasses has been studied in the temperature range 353-503K and in the frequency range 10Hz-2MHz . The dc conductivity increases and activation energy decreases with the increase of a particular alkaline earth content for the glasses with a fixed alkali content. The increased modification of the network due to the increase in alkaline earth content in the compositions is responsible for the increasing conductivity. Also the compositions with smaller alkaline earth ions were found to exhibit higher conductivity. Although the conductivity increases with the decrease of ionic radii of alkaline earth ions, the activation energy shows a maximum for the Sr ion. The electric modulus and the conductivity formalisms have been employed to study the relaxation dynamics of charge carriers in these glasses. The alkali ions were observed to change their dynamics with the change of the alkaline earth ions. The same anomalous trend for activation energy for the conductivity relaxation frequency and the hopping frequency was also observed for glasses containing SrO. It was also observed that the mobile lithium ion concentrations are independent of nature of alkaline earth ions in these glasses.

  15. Collective water dynamics in the first solvation shell drive the NMR relaxation of aqueous quadrupolar cations

    NASA Astrophysics Data System (ADS)

    Carof, Antoine; Salanne, Mathieu; Charpentier, Thibault; Rotenberg, Benjamin

    2016-09-01

    Using molecular simulations, we analyze the microscopic processes driving the Nuclear Magnetic Resonance (NMR) relaxation of quadrupolar cations in water. The fluctuations of the Electric Field Gradient (EFG) experienced by alkaline and magnesium cations, which determine the NMR relaxation time, are mainly due to the dynamics of water molecules in their solvation shell. The dynamics of the ion plays a less important role, with the exception of the short-time dynamics in the lighter Li+ case, for which rattling in the solvent cage results in oscillations of the EFG autocorrelation function (ACF). Several microscopic mechanisms that may a priori contribute to the decay of the EFG-ACF occur in fact over too long time scales: entrance/exit of individual water molecules into/from the solvation shell, rotation of a molecule around the ion, or reorientation of the molecule. In contrast, the fluctuations of the ion-water distance are clearly correlated to that of the EFG. Nevertheless, it is not sufficient to consider a single molecule due to the cancellations arising from the symmetry of the solvation shell. The decay of the EFG-ACF, hence NMR relaxation, is in fact governed by the collective symmetry-breaking fluctuations of water in the first solvation shell.

  16. Modeling for IFOG Vibration Error Based on the Strain Distribution of Quadrupolar Fiber Coil.

    PubMed

    Gao, Zhongxing; Zhang, Yonggang; Zhang, Yunhao

    2016-07-21

    Improving the performance of interferometric fiber optic gyroscope (IFOG) in harsh environment, especially in vibrational environment, is necessary for its practical applications. This paper presents a mathematical model for IFOG to theoretically compute the short-term rate errors caused by mechanical vibration. The computational procedures are mainly based on the strain distribution of quadrupolar fiber coil measured by stress analyzer. The definition of asymmetry of strain distribution (ASD) is given in the paper to evaluate the winding quality of the coil. The established model reveals that the high ASD and the variable fiber elastic modulus in large strain situation are two dominant reasons that give rise to nonreciprocity phase shift in IFOG under vibration. Furthermore, theoretical analysis and computational results indicate that vibration errors of both open-loop and closed-loop IFOG increase with the raise of vibrational amplitude, vibrational frequency and ASD. Finally, an estimation of vibration-induced IFOG errors in aircraft is done according to the proposed model. Our work is meaningful in designing IFOG coils to achieve a better anti-vibration performance.

  17. Modeling for IFOG Vibration Error Based on the Strain Distribution of Quadrupolar Fiber Coil

    PubMed Central

    Gao, Zhongxing; Zhang, Yonggang; Zhang, Yunhao

    2016-01-01

    Improving the performance of interferometric fiber optic gyroscope (IFOG) in harsh environment, especially in vibrational environment, is necessary for its practical applications. This paper presents a mathematical model for IFOG to theoretically compute the short-term rate errors caused by mechanical vibration. The computational procedures are mainly based on the strain distribution of quadrupolar fiber coil measured by stress analyzer. The definition of asymmetry of strain distribution (ASD) is given in the paper to evaluate the winding quality of the coil. The established model reveals that the high ASD and the variable fiber elastic modulus in large strain situation are two dominant reasons that give rise to nonreciprocity phase shift in IFOG under vibration. Furthermore, theoretical analysis and computational results indicate that vibration errors of both open-loop and closed-loop IFOG increase with the raise of vibrational amplitude, vibrational frequency and ASD. Finally, an estimation of vibration-induced IFOG errors in aircraft is done according to the proposed model. Our work is meaningful in designing IFOG coils to achieve a better anti-vibration performance. PMID:27455257

  18. Nuclear magnetic resonance of J-coupled quadrupolar nuclei: Use of the tensor operator product basis

    NASA Astrophysics Data System (ADS)

    Kemp-Harper, R.; Philp, D. J.; Kuchel, P. W.

    2001-08-01

    In nuclear magnetic resonance (NMR) of I=1/2 nuclei that are scalar coupled to quadrupolar spins, a tensor operator product (TOP) basis set provides a convenient description of the time evolution of the density operator. Expressions for the evolution of equivalent I=1/2 spins, coupled to an arbitrary spin S>1/2, were obtained by explicit algebraic density operator calculations in Mathematica, and specific examples are given for S=1 and S=3/2. Tensor operators are described by the convenient quantum numbers rank and order and this imparts to the TOP basis features that enable an intuitive understanding of NMR behavior of these spin systems. It is shown that evolution as a result of J coupling alone changes the rank of tensors for the coupling partner, generating higher-rank tensors, which allow efficient excitation of S-spin multiple-quantum coherences. Theoretical predictions obtained using the TOP formalism were confirmed using multiple-quantum filtered heteronuclear spin-echo experiments and were further employed to demonstrate polarization transfer directly to multiple-quantum transitions using the insensitive nucleus enhancement by polarization transfer pulse sequence. This latter experiment is the basis of two-dimensional heteronuclear correlation experiments and direct generation of multiple-quantum S-spin coherences can therefore be exploited to yield greater spectral resolution in such experiments. Simulated spectra and experimental results are presented.

  19. Effects of selective fusion on the thermal history of the earth's mantle

    USGS Publications Warehouse

    Lee, W.H.K.

    1968-01-01

    A comparative study on the thermal history of the earth's mantle was made by numerical solutions of the heat equation including and excluding selective fusion of silicates. Selective fusion was approximated by melting in a multicomponent system and redistribution of radioactive elements. Effects of selective fusion on the thermal models are (1) lowering (by several hundred degrees centigrade) and stabilizing the internal temperature distribution, and (2) increasing the surface heat-flow. It was found that models with selective fusion gave results more compatible with observations of both present temperature and surface heat-flow. The results therefore suggest continuous differentiation of the earth's mantle throughout geologic time, and support the hypothesis that the earth's atmosphere, oceans, and crust have been accumulated throughout the earth's history by degassing and selective fusion of the mantle. ?? 1968.

  20. Effect of limb darkening on earth radiation incident on a spherical satellite

    NASA Technical Reports Server (NTRS)

    Katzoff, S.; Smith, G. L.

    1974-01-01

    The thermal radiation from the earth incident on a spherical satellite depends on the angular distribution of earth-emitted radiation. An analysis is presented of this dependency, and calculated results are given, based on a published limb-darkening curve for the earth. The curve was determined from Tiros data, and is a statistical average over the entire globe between 75 deg latitude. The computed effect of limb darkening was 1.8 percent at 900 km altitude, 2.5 percent at 500 km altitude, and 3.0 percent at 300 km altitude. Below 300 km, it increased rapidly with decreasing altitude. Discussion is included of various other problems inherent in the use of orbiting spheres and stabilized flat plates to measure the heat radiated from the earth.

  1. Effects of Rare-Earth Oxides on the Reliability of X7R Dielectrics

    NASA Astrophysics Data System (ADS)

    Sakabe, Yukio; Hamaji, Yukio; Sano, Harunobu; Wada, Nobuyuki

    2002-09-01

    The effects of rare-earth oxides, e.g., La, Nd, Sm, Dy and Yb, on the reliability of multilayer capacitors (MLCs) with X7R dielectrics and Ni electrodes were investigated. Microstructures of the dielectrics were analyzed by transmission electron microscopy (TEM) and electron probe microanalysis (EPMA) in order to characterize the rare-earth ions. Incorporation of rare-earth ions to BaTiO3 ceramics depended on their ionic radius, resulting in different microstructures and electric performances of dielectrics. Dy ions provided BaTiO3 ceramics with ideal X7R characteristics and high reliability. The mechanism governing leakage current was discussed in terms of the voltage dependence of leakage current. Electric properties and related reliability of the capacitors were attributed to solubility, distribution of rare-earth oxides and their occupation site in BaTiO3.

  2. Using the Earth as an Effective Model for Integrating Space Science Into Education Outreach Programs

    NASA Astrophysics Data System (ADS)

    Morris, P. A.; Allen, J.; Galindo, C.; McKay, G.; Obot, V.; Reiff, P.

    2005-05-01

    Our methods of teaching Earth and space science as two disciplines do not represent the spirit of earlier scientists such as Aristotle, da Vinci, and Galileo. We need to re-evaluate these methods and take advantage of the excitement created in the general public over the recent space science exploration programs. The information that we are obtaining from both the Mars missions and Cassini-Huygens focuses on interpreting geomorphology, mineral compositions and gas identification based on Earth as a baseline for data evaluation. This type of evaluation is an extension of Hutton's 18th century principle of Uniformitarianism, the present is the key to the past, or Earth is the key for understanding extraterrestrial bodies. Geomorphological examples are volcanic activity, meteoritic impacts, and evidence of water altering surface features. The Hawaiian, or shield, type volcanoes are analogues for Olympus Mons and the other volcanoes on Mars. Other examples include comparing sand dunes on Earth with possible Martian dunes, known stream patterns on Earth with potential stream patterns on Mars, and even comparing meteoritic impact features on Mars, the Earth, Moon and Mercury. All of these comparisons have been developed into inquiry-based activities and are available through NASA publications. Each of these activities is easily adapted to emphasize either Earth science or space science or both. Beyond geomorphology, solar storms are an excellent topic for integrating Earth and space science. Solar storms are traditionally part of space science studies, but most students do not understand their effect on Earth or the intense effects they could have on humans, whether traveling through space or exploring the surfaces of the Moon or Mars. Effects are not only limited to space travel and other planetary surfaces but also include Earth's magnetosphere, which in turn, affect radio transmission and potentially climate. Like geomorphology courses, there are extensive NASA

  3. Perceived Barriers and Strategies to Effective Online Earth and Space Science Instruction

    NASA Astrophysics Data System (ADS)

    Pottinger, James E.

    With the continual growth and demand of online courses, higher education institutions are attempting to meet the needs of today's learners by modifying and developing new student centered services and programs. As a result, faculty members are being forced into teaching online, including Earth and Space science faculty. Online Earth and Space science courses are different than typical online courses in that they need to incorporate an inquiry-based component to ensure students fully understand the course concepts and science principles in the Earth and Space sciences. Studies have addressed the barriers in other inquiry-based online science courses, including biology, physics, and chemistry. This holistic, multiple-case qualitative study investigated perceived barriers and strategies to effective online Earth and Space science instruction through in-depth interviews with six experienced post-secondary online science instructors. Data from this study was analyzed using a thematic analysis approach and revealed four common themes when teaching online Earth and Space science. A positive perception and philosophy of online teaching is essential, the instructor-student interaction is dynamic, course structure and design modification will occur, and online lab activities must make science operational and relevant. The findings in this study demonstrated that online Earth and Space science instructors need institutional support in the form of a strong faculty development program and support staff in order to be as effective as possible. From this study, instructors realize that the instructor-student relationship and course structure is paramount, especially when teaching online science with labs. A final understanding from this study was that online Earth and Space science lab activities must incorporate the use and application of scientific skills and knowledge. Recommendations for future research include (a) qualitative research conducted in specific areas within the

  4. Effect of the shrinking dipole on solar-terrestrial energy input to the Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    McPherron, R. L.

    2011-12-01

    The global average temperature of the Earth is rising rapidly. This rise is primarily attributed to the release of greenhouse gases as a result of human activity. However, it has been argued that changes in radiation from the Sun might play a role. Most energy input to the Earth is light in the visible spectrum. Our best measurements suggest this power input has been constant for the last 40 years (the space age) apart from a small 11-year variation due to the solar cycle of sunspot activity. Another possible energy input from the Sun is the solar wind. The supersonic solar wind carries the magnetic field of the Sun into the solar system. As it passes the Earth it can connect to the Earth's magnetic field whenever it is antiparallel t the Earth's field. This connection allows mass, momentum, and energy from the solar wind to enter the magnetosphere producing geomagnetic activity. Ultimately much of this energy is deposited at high latitudes in the form of particle precipitation (aurora) and heating by electrical currents. Although the energy input by this process is miniscule compared to that from visible radiation it might alter the absorption of visible radiation. Two other processes affected by the solar cycle are atmospheric entry of galactic cosmic rays (GCR) and solar energetic protons (SEP). A weak solar magnetic field at sunspot minimum facilitates GCR entry which has been implicated in creation of clouds. Large coronal mass ejections and solar flares create SEP at solar maximum. All of these alternative energy inputs and their effects depend on the strength of the Earth's magnetic field. Currently the Earth's field is decreasing rapidly and conceivably might reverse polarity in 1000 years. In this paper we describe the changes in the Earth's magnetic field and how this might affect GCR, SEP, electrical heating, aurora, and radio propagation. Whether these effects are important in global climate change can only be determined by detailed physical models.

  5. Relativity mission with two counter-orbiting polar satellites. [nodal dragging effect on earth orbiting satellites

    NASA Technical Reports Server (NTRS)

    Van Patten, R. A.; Everitt, C. W. F.

    1975-01-01

    In 1918, J. Lense and H. Thirring calculated that a moon in orbit around a massive rotating planet would experience a nodal dragging effect due to general relativity. We describe an experiment to measure this effect with two counter-orbiting drag-free satellites in polar earth orbit. For a 2 1/2 year experiment, the measurement accuracy should approach 1%. In addition to precision tracking data from existing ground stations, satellite-to-satellite Doppler ranging data are taken at points of passing near the poles. New geophysical information on both earth harmonics and tidal effects is inherent in the polar ranging data.

  6. Effect of Solar Variability on Earth Climate Patterns.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Feynman, J.

    2006-12-01

    We discuss the impact of solar variability on the patterns of Earth climate variability. These climate patterns are naturally excited in the noisy atmosphere-ocean dynamical system as deviations (anomalies) from a global (mean) state. The patterns include North Atlantic Oscillation (NAO) and related Northern Annular Mode (NAM), Southern Annular Mode (SAM), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO). An example of a pattern influenced by variations in solar UV irradiance is the NAM, a wintertime climate anomaly with two states corresponding to higher pressure at high latitudes with a band of lower pressure at lower latitudes and the other way round (Thompson &Wallace, 1998). Two states of the NAM arise due to the dynamical interaction of planetary waves and zonal mean wind (Limpasuvan &Hartmann, 2001; Ruzmaikin et al., 2006). The NAM accounts for 23% of atmospheric variability at sea level and about 50% of the variability in the stratosphere. Solar variability affects the NAM and that the influence varies dependent on the phase of the Quasi Biennial Oscillation and time in the winter season (Ruzmaikin &Feynman, 2002). The temperature pattern (cold in Europe-warm in Greenland) produced by the negative NAM was dominant during the Maunder Minimum of solar activity (Ruzmaikin et al., 2004). We discuss possible physical mechanisms by which solar variability can influence the climate patterns. In particular, we address the Rossby-Palmer hypothesis (Palmer, 1998) that external forcing (in our case solar variability) may affect only the magnitude of the pattern variability without changing its spatial structure. References: Thompson, D. W. J. &J. M. Wallace, Geophys. Res. Lett., 25, 1297, 1998; Palmer, T. N., Bull. Amer. Meteor. Soc., 79, 1412 1998; Baldwin, M. P. and T. J. Dunkerton, J. Geophys. Res. 104, 30,937, 1999; Limpasuvan, V., &D. Hartmann, J. Climate, 13, 4414, 2001; Ruzmaikin, A., J, Feynman, J. Geophys. Res., 107, D14, 10

  7. The effect of SST emissions on the earth's ozone layer

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Turco, R. P.

    1974-01-01

    The work presented here is directed toward assessment of environmental effects of the supersonic transport (SST). The model used for the purpose includes vertical eddy transport and the photochemistry of the O-H-N system. It is found that the flight altitude has a pronounced effect on ozone depletion. The largest ozone reduction occurs for NO deposition above an altitude of 20 km.

  8. Plasma and magnetic field variations in the distant magnetotail associated with near-earth substorm effects

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Bame, S. J.; Mccomas, D. J.; Zwickl, R. D.; Slavin, J. A.; Smith, E. J.

    1987-01-01

    Examination of many individual event periods in the ISEE 3 deep-tail data set has suggested that magnetospheric substorms produce a characteristic pattern of effects in the distant magnetotail. During the growth, or tail-energy-storage phase of substorms, the magnetotail appears to grow diametrically in size, often by many earth radii. Subsequently, after the substorm expansive phase onset at earth, the distant tail undergoes a sequence of plasma, field, and energetic-particle variations as large-scale plasmoids move rapidly down the tail following their disconnection from the near-earth plasma sheet. ISEE 3 data are appropriate for the study of these effects since the spacecraft remained fixed within the nominal tail location for long periods. Using newly available auroral electrojet indices (AE and AL) and Geo particle data to time substorm onsets at earth, superposed epoch analyses of ISEE 3 and near-earth data prior to, and following, substorm expansive phase onsets have been performed. These analyses quantify and extend substantially the understanding of the deep-tail pattern of response to global substorm-induced dynamical effects.

  9. Relativistic Effect on Multiplet Terms of Rare Earth Ions

    NASA Astrophysics Data System (ADS)

    Itoh, Shinichi; Saito, Riichiro; Kimura, Tadamasa; Yabushita, Satoshi

    1994-02-01

    Ab initio Spin-Orbit Configuration Interaction (SOCI) calculations for the trivalent lanthanide group ions are presented for the special purpose to investigate the relativistic SO effects on their multiplet terms. The effective nuclear charges (Z eff's) for one-body spin-orbit Hamiltonian are calculated by an atomic Dirac-Slater Xα equation and applied to the lanthanide ions. The relativistic effects of core electrons can easily be included in the reduction of Z eff and the multiplet levels shift up to 200 cm-1 by the reduction. The multiplet energies obtained by the present method are in good agreement with experimental values.

  10. Climatic effects due to halogenated compounds in the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Wang, W.-C.; Pinto, J. P.; Yung, Y. L.

    1980-01-01

    Using a one-dimensional radiative-convective model, a sensitivity study is performed of the effect of ozone depletion in the stratosphere on the surface temperature. There could be a cooling of the surface temperature by approximately 0.2 K due to chlorofluoromethane-induced ozone depletion at steady state (assuming 1973 release rates). This cooling reduces significantly the greenhouse effect due to the presence of chlorofluoromethanes. Carbon tetrafluoride has a strong nu sub 3 band at 7.8 microns, and the atmospheric greenhouse effect is shown to be 0.07 and 0.12 K/ppbv with and without taking into account overlap with CH4 and N2O bands. At concentrations higher than 1 ppbv, absorption by the nu sub 3 band starts to saturate and the greenhouse effect becomes less efficient.

  11. Thulium anomalies and rare earth element patterns in meteorites and Earth: Nebular fractionation and the nugget effect

    NASA Astrophysics Data System (ADS)

    Dauphas, Nicolas; Pourmand, Ali

    2015-08-01

    This study reports the bulk rare earth element (REEs, La-Lu) compositions of 41 chondrites, including 32 falls and 9 finds from carbonaceous (CI, CM, CO and CV), enstatite (EH and EL) and ordinary (H, L and LL) groups, as well as 2 enstatite achondrites (aubrite). The measurements were done in dynamic mode using multi-collector inductively coupled plasma mass spectrometers (MC-ICPMS), allowing precise quantification of mono-isotopic REEs (Pr, Tb, Ho and Tm). The CI-chondrite-normalized REE patterns (LaN/LuN; a proxy for fractionation of light vs. heavy REEs) and Eu anomalies in ordinary and enstatite chondrites show more scatter in more metamorphosed (petrologic types 4-6) than in unequilibrated (types 1-3) chondrites. This is due to parent-body redistribution of the REEs in various carrier phases during metamorphism. A model is presented that predicts the dispersion of elemental and isotopic ratios due to the nugget effect when the analyzed sample mass is limited and elements are concentrated in minor grains. The dispersion in REE patterns of equilibrated ordinary chondrites is reproduced well by this model, considering that REEs are concentrated in 200 μm-size phosphates, which have high LaN/LuN ratios and negative Eu anomalies. Terrestrial rocks and samples from ordinary and enstatite chondrites display negative Tm anomalies of ∼-4.5% relative to CI chondrites. In contrast, CM, CO and CV (except Allende) show no significant Tm anomalies. Allende CV chondrite shows large excess Tm (∼+10%). These anomalies are similar to those found in group II refractory inclusions in meteorites but of much smaller magnitude. The presence of Tm anomalies in meteorites and terrestrial rocks suggests that either (i) the material in the inner part of the solar system was formed from a gas reservoir that had been depleted in refractory dust and carried positive Tm anomalies or (ii) CI chondrites are enriched in refractory dust and are not representative of solar composition for

  12. Earth tides

    SciTech Connect

    Harrison, J.C.

    1984-01-01

    Nineteen papers on gravity, tilt, and strain tides are compiled into this volume. Detailed chapters cover the calculation of the tidal forces and of the Earth's response to them, as well as actual observations of earth tides. Partial Contents: On Earth tides. The tidal forces: Tidal Forces. New Computations of the Tide-Generating Potential. Corrected Tables of Tidal Harmonics. The Theory of Tidal Deformations. Body Tides on an Elliptical, Rotating, Elastic and Oceanless Earth, Deformation of the Earth by Surface Loads. Gravimetric Tidal Loading Computed from Integrated Green's Functions. Tidal Friction in the Solid Earth. Loading Tides Versus Body Tides. Lunar Tidal Acceleration from Earth Satellite Orbit Analysis. Observations: gravity. Tidal Gravity in Britain: Tidal Loading and the Spatial Distribution of the Marine Tide. Tidal Loading along a Profile Europe-East Africa-South Asia-Australia and the Pacific Ocean. Detailed Gravity-Tide Spectrum between One and Four Cycles per Day. Observations: tilt and strain. Cavity and Topographic Effects in Tilt and Strain Measurement. Observations of Local Elastic Effects on Earth Tide Tilts and Strains.

  13. Galactic cosmic rays - atmosphere clouds effect and bifurcation model of the Earth global climate

    NASA Astrophysics Data System (ADS)

    Glushkov, Alexander

    The possible physical linkage between the cosmic rays, atmosphere cloud and indirect aerosol effects is discussed using analysis of first indirect aerosol effect (Twomey effect) and its experimental representation as the dependence of mean cloud droplet effective radius versus aerosol index defining the column aerosol number. It is shown that the main kinetic equation of Earth climate energy-balance model [1] is described by the bifurcation equation (relative to the Earth surface temperature) in the form of fold catastrophe with two controlling parameters defining the variations of insolation and Earth magnetic field (or cosmic rays intensity in the atmosphere) respectively. The results of comparative analysis on the time-dependent solution (time series of global paleotemperature ) of Earth climate energy-balance model taking into account nontrivial role of galactic cosmic rays and the known experimental data on the palaeotemperature from the EPICA Dome C and Vostok ice core are pre-sented. It is discussed the sin-earth mechanism of arising the abnormal temperature breaks which are observed in the EPICA Dome C and Vostok experiments. It has been found its link with the ‘order-chaos' transitions in evolution of the convection in the Earth liquid core which are responsible for mechanism of arising inversions of the magnetic field of the Earth. It should be noted a stabilization role of the slow nuclear burning [1] georeactor with power 30 TW) on the boundary of the liquid and solid phases of the Earth's core in evolution of convection in the Earth liquid core and magnetic field. In the bifurcation model (i) the possibility of abrupt glacial climate changes analogous to the Dansgaard-Oeschger events due to stochastic resonance is theoretically argued, (ii) the concept of the climatic sensitivity of water (vapour and liquid) in the atmosphere is introduced. This concept reveals the property of temperature instability in a form of so-called hysteresis loop. It is

  14. Effects of dynamic long-period ocean tides on changes in earth's rotation rate

    NASA Technical Reports Server (NTRS)

    Nam, Young; Dickman, S. R.

    1990-01-01

    As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the zonal response function kappa of the solid earth-ocean system is defined as the ratio, in the frequency domain, of the tidal change in earth's rotation rate to the tide-generating potential. Amplitudes and phases of kappa for the monthly, fortnightly, and nine-day lunar tides are estimated from 2 1/2 years of VLBI UT1 observations, corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988, 1989), amplitudes and phases of kappa for an elastic earth-ocean system are predicted. The predictions confirm earlier results which found that dynamic effects of the longer-period ocean tides reduce the amplitude of kappa by about 1 percent.

  15. Influence of sodium ion dynamics on the 23Na quadrupolar interaction in sodalite: a high-temperature 23Na MAS NMR study.

    PubMed

    Fechtelkord, M

    2000-01-01

    High-temperature 33Na MAS NMR experiments up to 873 K for a number of different sodalites (Na8[AlSiO4]6(NO3)2, Na8[AlSiO4]6(NO2)2, Na8[AlSiO4]6I2, Na7.9[AlSiO4]6(SCN)7.9 x 0.5H2O, Na8[AlGeO4]6(NO3)2, and Na7[AlSiO4]6(H3O2) x 4H2O) were carried out. The spectra of the first five sodalites consist of a quadrupolar MAS pattern with different quadrupolar coupling constants. The quadrupolar interaction for the thiocyanate sodalite, the nitrate aluminosilicate, and germanate sodalite decreases strongly passing a coalescence state on heating, while the quadrupolar interaction of the iodide and nitrite sample shows nearly no change. The basic hydrosodalite shows an asymmetric lineshape at room temperature and, between 350 and 370 K, a second line due to the evaporation of cage-water emerges. The linewidth increases with rising temperature. The temperature dependence of the quadrupolar interaction seems to be a function of the sodalite beta-cage expansion. Two conceivable jump mechanisms are proposed for a tetrahedral two-site jump between occupied and unoccupied tetrahedral sites.

  16. Two-photon absorption properties of proquinoidal D-A-D and A-D-A quadrupolar chromophores.

    PubMed

    Susumu, Kimihiro; Fisher, Jonathan A N; Zheng, Jieru; Beratan, David N; Yodh, Arjun G; Therien, Michael J

    2011-06-09

    We report the synthesis, one- and two-photon absorption spectroscopy, fluorescence, and electrochemical properties of a series of quadrupolar molecules that feature proquinoidal π-aromatic acceptors. These quadrupolar molecules possess either donor-acceptor-donor (D-A-D) or acceptor-donor-acceptor (A-D-A) electronic motifs, and feature 4-N,N-dihexylaminophenyl, 4-dodecyloxyphenyl, 4-(N,N-dihexylamino)benzo[c][1,2,5]thiadiazolyl or 2,5-dioctyloxyphenyl electron donor moieties and benzo[c][1,2,5]thiadiazole (BTD) or 6,7-bis(3',7'-dimethyloctyl)[1,2,5]thiadiazolo[3,4-g]quinoxaline (TDQ) electron acceptor units. These conjugated structures are highly emissive in nonpolar solvents and exhibit large spectral red-shifts of their respective lowest energy absorption bands relative to analogous reference compounds that incorporate phenylene components in place of BTD and TDQ moieties. BTD-based D-A-D and A-D-A chromophores exhibit increasing fluorescence emission red-shifts, and a concomitant decrease of the fluorescence quantum yield (Φ(f)) with increasing solvent polarity; these data indicate that electronic excitation augments benzothiadiazole electron density via an internal charge transfer mechanism. The BTD- and TDQ-containing structures exhibit blue-shifted two-photon absorption (TPA) spectra relative to their corresponding one-photon absorption (OPA) spectra, and display high TPA cross sections (>100 GM) within these spectral windows. D-A-D and A-D-A structures that feature more extensive conjugation within this series of compounds exhibit larger TPA cross sections consistent with computational simulation. Factors governing TPA properties of these quadrupolar chromophores are discussed within the context of a three-state model.

  17. Two-Photon Absorption Properties of Proquinoidal D-A-D and A-D-A Quadrupolar Chromophores

    PubMed Central

    Susumu, Kimihiro; Fisher, Jonathan A. N.; Zheng, Jieru

    2011-01-01

    We report the synthesis, one- and two-photon absorption spectroscopy, fluorescence, and electrochemical properties of a series of quadrupolar molecules that feature proquinoidal π-aromatic acceptors. These quadrupolar molecules possess either donor-acceptor-donor (D–A–D) or acceptor-donor-acceptor (A–D–A) electronic motifs, and feature 4-N,N-dihexylaminophenyl, 4-dodecyloxyphenyl, 4-(N,N-dihexylamino)benzo[c][1,2,5]thiadiazolyl or 2,5-dioctyloxyphenyl electron donor moieties and benzo[c][1,2,5]thiadiazole (BTD) or 6,7-bis(3’,7’-dimethyloctyl)[1,2,5]thiadiazolo[3,4-g]quinoxaline (TDQ) electron acceptor units. These conjugated structures are highly emissive in nonpolar solvents and exhibit large spectral red-shifts of their respective lowest energy absorption bands relative to analogous reference compounds that incorporate phenylene components in place of BTD and TDQ moieties. BTD-based D-A-D and A-D-A chromophores exhibit increasing fluorescence emission red-shifts, and a concomitant decrease of the fluorescence quantum yield (Φf) with increasing solvent polarity; these data indicate that electronic excitation augments benzothiadiazole electron density via an internal charge transfer mechanism. The BTD- and TDQ-containing structures exhibit blue-shifted two-photon absorption (TPA) spectra relative to their corresponding one-photon absorption (OPA) spectra, and display high TPA cross-sections (>100 GM) within these spectral windows. D-A-D and A-D-A structures that feature more extensive conjugation within this series of compounds exhibit larger TPA cross-sections consistent with computational simulation. Factors governing TPA properties of these quadrupolar chromophores are discussed within the context of a three-state model. PMID:21568299

  18. Global single ion effects within the Earth's plasma sheet

    NASA Astrophysics Data System (ADS)

    Rothwell, Paul L.; Yates, G. Kenneth

    Two global properties of single ion motion in the magnetotail are examined. The first effect is caused by the magnetic field in the plasma sheet directing boundary ions to the neutral sheet. Exact solutions to the Lorentz equation indicate that these ions can have sufficient energy to trigger the ion tearing mode if Bo/aBz > 6.0, where Bo is the tail lobe magnetic field, Bz is the magnetic field in the north-south direction and `a' is a parameter related to the growth of the ion tearing instability. It is found that this effect occurs at a lower energy for oxygen than for protons. The second global property is related to the thinning or expansion of the plasma sheet. The results indicate that in the absence of reconnection the plasma sheet adiabatically maintains equilibruim by allowing plasma and magnetic flux to cross the boundaries. The presence of reconnection modifies the flow across the boundaries as well as the spatial distribution of the induced electric field.

  19. Global single ion effects within the earth's plasma sheet

    NASA Astrophysics Data System (ADS)

    Rothwell, P. L.; Yates, G. K.

    Two global properties of single-ion motion in the magnetotail are examined. The first effect is caused by the magnetic field in the plasma sheet directing boundary ions to the neutral sheet. Exact solutions to the Lorentz equation indicate that these ions can have sufficient energy to trigger the ion tearing mode if B0/aBz is greater than 6.0, where B0 is the tail-lobe magnetic field, Bz is the magnetic field in the north-south direction, and a is a parameter related to the growth of the ion tearing instability. It is found that this effect occurs at a lower energy for oxygen than for protons. The second global property is related to the thinning or expansion of the plasma sheet. In the absence of reconnection, the plasma sheet adiabatically maintains equilibrium by allowing plasma and magnetic flux to cross the boundaries. The presence of reconnection modifies the flow across the boundaries as well as the spatial distribution of the induced electric field.

  20. Application of static microcoils and WURST pulses for solid-state ultra-wideline NMR spectroscopy of quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Tang, Joel A.; O'Dell, Luke A.; Aguiar, Pedro M.; Lucier, Bryan E. G.; Sakellariou, Dimitris; Schurko, Robert W.

    2008-12-01

    The uses of microcoils and WURST pulses for acquiring ultra-wideline (UW) NMR spectra of half-integer quadrupolar nuclei are explored. Using large rf field strengths or frequency-swept pulses, UW spectra (breadth > 300 kHz) can be acquired without changing the transmitter frequency. The efficiency of UWNMR spectroscopy improves for both microcoil and WURST pulse experiments compared to rectangular-pulse experiments using a 4.0 mm coil. Microcoils are also used to acquire UW spectra of an unreceptive nucleus ( 91Zr) and a spectrum comprised of both central and satellite transitions ( 59Co).

  1. Low Earth Orbit Environmental Effects on Space Tether Materials

    NASA Technical Reports Server (NTRS)

    Finckernor, Miria M.; Gitlemeier, Keith A.; Hawk, Clark W.; Watts, Ed

    2005-01-01

    Atomic oxygen (AO) and ultraviolet (UV) radiation erode and embrittle most polymeric materials. This research was designed to test several different materials and coatings under consideration for their application to space tethers, for resistance to these effects. The samples were vacuum dehydrated, weighed and then exposed to various levels of AO or UV radiation at the NASA Marshall Space Flight Center. They were then re-weighed to determine mass loss due to atomic oxygen erosion, inspected for damage and tensile tested to determine strength loss. The experiments determined that the Photosil coating process, while affording some protection, damaged the tether materials worse than the AO exposure. TOR-LM also failed to fully protect the materials, especially from UV radiation. The POSS and nickel coatings did provide some protection to the tethers, which survived the entire test regime. M5 was tested, uncoated, and survived AO exposure, though its brittleness prevented any tensile testing.

  2. Imaging the earth's magnetosphere - Effects of plasma flow and temperature

    NASA Technical Reports Server (NTRS)

    Garrido, D. E.; Smith, R. W.; Swift, D. S.; Akasofu, S.-I.

    1991-01-01

    The effects of Doppler shifting on the line centers of the magnetospheric O(+) cross section are investigated, and the resulting structure of the scattering rate as a function of bulk density is explained. Whereas the Doppler shifting frequently results in a decrease of the scattering rate, it is demonstrated that for certain drift speeds the overlap of the cross section and the solar intensity profile can lead to an increased rate, thus enhancing the relative brightness of the image above that obtained when v(p) is zero. Simulated images of the magnetosphere are obtained which are used to show quantitively how the magnetospheric image responds to variations in plasma drift speed and temperature. Changes in the brightness of the magnetospheric images also depend on the variability of the solar flux at 83.4 nm. In regions where there are plasma drifts, the brightness in the image is governed by the structure of the scattering rate, assuming a fixed temperature.

  3. The Effects of an Earth Science Curriculum Revision on Teacher Behavior and Student Achievement. Final Report.

    ERIC Educational Resources Information Center

    Orgren, James R.

    A two-year study on the effects of adopting the 1970 revision of the New York State Regents Earth Science Syllabus on teachers' teaching strategies and educational opinions and students' abilities and performance was reported. A total of about 30 teachers and their classrooms were used. One group used the old syllabus in the first year and the new…

  4. Effects of dynamic long-period ocean tides on changes in Earth's rotation rate

    SciTech Connect

    Nam, Y.S.; Dickman, S.R. )

    1990-05-10

    As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the authors define the zonal response function k of the solid earth-ocean system as the ratio, in the frequency domain, of the tidal change in Earth's rotation rate to the tide-generating potential. Amplitudes and phases of k for the monthly, fortnightly, and 9-day lunar tides are estimated from 2 1/2 years of very long baseline interferometry UTI observations (both 5-day and daily time series), corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988a, 1989a), the authors predict amplitudes and phases of k for an elastic earth-ocean system. The predictions confirm earlier results which found that dynamic effects of the longer-period ocean tides reduce the amplitude of k by about 1%. However, agreement with the observed k is best achieved for all three tides if the predicted tide amplitudes are combined with the much larger satellite-observed ocean tide phases; in these cases the dynamic tidal effects reduce k by up to 8%. Finally, comparison between the observed and predicted amplitudes of k implies that anelastic effects on Earth's rotation at periods less than fortnightly cannot exceed 2%.

  5. Relativistic effects of the rotation of the earth on remote clock synchronization

    NASA Technical Reports Server (NTRS)

    Reinhardt, V.

    1974-01-01

    A treatment is given of relativistic clock synchronization effects due to the rotation of the earth. Unlike other approaches, the point of view of an earth fixed coordinate system is used which offers insight to many problems. An attempt is made to give the reader an intuitive grasp of the subject as well as to provide formulae for his use. Specific applications to global timekeeping, navigation, VLBI, relativistic clock experiments, and satellite clock synchronization are discussed. The question of whether atomic clocks are ideal clocks is also treated.

  6. The effects of solar Reimers η on the final destinies of Venus, the Earth, and Mars

    NASA Astrophysics Data System (ADS)

    Guo, Jianpo; Lin, Ling; Bai, Chunyan; Liu, Jinzhong

    2016-04-01

    Our Sun will lose sizable mass and expand enormously when it evolves to the red giant branch phase and the asymptotic giant branch phase. The loss of solar mass will push a planet outward. On the contrary, solar expansion will enhance tidal effects, and tidal force will drive a planet inward. Will our Sun finally engulf Venus, the Earth, and Mars? In the literature, one can find a large number of studies with different points of view. A key factor is that we do not know how much mass the Sun will lose at the late stages. The Reimers η can describe the efficiency of stellar mass-loss and greatly affect solar mass and solar radius at the late stages. In this work, we study how the final destinies of Venus, the Earth, and Mars can be depending on Reimers η chosen. In our calculation, the Reimers η varies from 0.00 to 0.75, with the minimum interval 0.0025. Our results show that Venus will be engulfed by the Sun and Mars will most probably survive finally. The fate of the Earth is uncertain. The Earth will finally be engulfed by the Sun while η <0.4600, and it will finally survive while η ≥ 0.4600. New observations indicate that the average Reimers η for solar-like stars is 0.477. This implies that Earth may survive finally.

  7. Crystal-field interaction and oxygen stoichiometry effects in strontium-doped rare-earth cobaltates

    NASA Astrophysics Data System (ADS)

    Furrer, A.; Podlesnyak, A.; Frontzek, M.; Sashin, I.; Embs, J. P.; Mitberg, E.; Pomjakushina, E.

    2014-08-01

    Inelastic neutron scattering was employed to study the crystal-field interaction in the strontium-doped rare-earth compounds RxSr1-xCoO3-z (R=Pr, Nd, Ho, and Er). Particular emphasis is laid on the effect of oxygen deficiencies that naturally occur in the synthesis of these compounds. The observed energy spectra are found to be the result of a superposition of crystal fields with different nearest-neighbor oxygen coordination at the R sites. The experimental data are interpreted in terms of crystal-field parameters, which behave in a consistent manner through the rare-earth series, thereby allowing a reliable extrapolation for rare-earth ions not considered in the present work.

  8. The Study of Effects of Time Variations in the Earth's Gravity Field on Geodetic Satellites

    NASA Technical Reports Server (NTRS)

    Shum, C. K.

    1998-01-01

    The temporal variations in the Earth's gravity field are the consequences of complex interactions between atmosphere, ocean, solid Earth, hydrosphere and cryosphere. The signal ranges from several hours to 18.6 years to geological time scale. The direct and indirect consequences of these variations are manifested in such phenomena as changes in the global sea level and in the global climate pattern. These signals produce observable geodetic satellites. The primary objectives of the proposed effects on near-Earth orbiting investigation include (1) the improved determination of the time-varying gravity field parameters (scale from a few hour to 18.6 year and secular) using long-term satellite laser rs ranging (SLR) observations to multiple geodetic satellites, and (2) the enhanced understanding of these variations with their associated meteorological and geophysical consequences.

  9. Spatial nonlinearities: Cascading effects in the earth system

    USGS Publications Warehouse

    Peters, Debra P.C.; Pielke, R.A.; Bestelmeyer, B.T.; Allen, Craig D.; Munson-McGee, S.; Havstad, K. M.

    2006-01-01

    Nonlinear interactions and feedbacks associated with thresholds through time and across space are common features of biological, physical and materials systems. These spatial nonlinearities generate surprising behavior where dynamics at one scale cannot be easily predicted based on information obtained at finer or broader scales. These cascading effects often result in severe consequences for the environment and human welfare (i.e., catastrophes) that are expected to be particularly important under conditions of changes in climate and land use. In this chapter, we illustrate the usefulness of a general conceptual and mathematical framework for understanding and forecasting spatially nonlinear responses to global change. This framework includes cross-scale interactions, threshold behavior and feedback mechanisms. We focus on spatial nonlinearities produced by fine-scale processes that cascade through time and across space to influence broad spatial extents. Here we describe the spread of catastrophic events in the context of our cross-disciplinary framework using examples from biology (wildfires, desertification, infectious diseases) and engineering (structural failures) and discuss the consequences of applying these ideas to forecasting future dynamics under a changing global environment.

  10. The Effect of Rare Earth Dopants on UO2 Oxidation

    SciTech Connect

    Hanson, Brady D.; Cumblidge, Stephen E.; Scheele, Randall D.; Sell, Rachel L.

    2003-06-01

    Recent work by Hanson [1] has demonstrated a clear dependence of the oxidation of Light Water Reactor spent fuel on burnup. Oxidation of spent fuel was shown to proceed via the two-step reaction UO2?UO2.4?UO2.67+x, where the U3O8-like phase does not form until conversion to UO2.4 is complete. The temperature-dependent activation energy (Ea) of the transition from UO2.4 to the hyperstoichiometric U3O8 was found to be {approx}150 kJ mol-1. Each MWD/kg M burnup added {approx}1.0 kJ mol-1. The work of McEachern et.al. [2], Choi et. al. [3], and You et. al. [4] have all verified this oxidation dependence on SIMFUEL or unirradiated doped-UO2. All present work agrees that the soluble actinides or fission products that substitute in the U matrix act to delay the onset of U3O8. However, no single model exists to explain the observed behavior, including the fact that most dopants actually allow an earlier onset for UO2.4 formation. The present work is part of a Nuclear Energy Research Initiative project attempting to develop a UO2-based matrix capable of achieving extended burnups by including soluble dopants. The resulting fuel should be highly oxidation and dissolution resistant, which will be beneficial during accident scenarios or for disposal in a geologic repository. In addition, the stabilized matrix may help delay the onset of fuel restructuring that occurs at higher burnups. Initial results of the oxidation tests to quantify effects as a function of ionic radii and charge of the dopant are presented.

  11. The Effect of the Earth's and Stray Magnetic Fields on Mobile Mass Spectrometer Systems

    NASA Astrophysics Data System (ADS)

    Bell, Ryan J.; Davey, Nicholas G.; Martinsen, Morten; Short, R. Timothy; Gill, Chris G.; Krogh, Erik T.

    2015-02-01

    Development of small, field-portable mass spectrometers has enabled a rapid growth of in-field measurements on mobile platforms. In such in-field measurements, unexpected signal variability has been observed by the authors in portable ion traps with internal electron ionization. The orientation of magnetic fields (such as the Earth's) relative to the ionization electron beam trajectory can significantly alter the electron flux into a quadrupole ion trap, resulting in significant changes in the instrumental sensitivity. Instrument simulations and experiments were performed relative to the earth's magnetic field to assess the importance of (1) nonpoint-source electron sources, (2) vertical versus horizontal electron beam orientation, and (3) secondary magnetic fields created by the instrument itself. Electron lens focus effects were explored by additional simulations, and were paralleled by experiments performed with a mass spectrometer mounted on a rotating platform. Additionally, magnetically permeable metals were used to shield (1) the entire instrument from the Earth's magnetic field, and (2) the electron beam from both the Earth's and instrument's magnetic fields. Both simulation and experimental results suggest the predominant influence on directionally dependent signal variability is the result of the summation of two magnetic vectors. As such, the most effective method for reducing this effect is the shielding of the electron beam from both magnetic vectors, thus improving electron beam alignment and removing any directional dependency. The improved ionizing electron beam alignment also allows for significant improvements in overall instrument sensitivity.

  12. Earth matter effects on supernova neutrinos in large-volume detectors

    NASA Astrophysics Data System (ADS)

    Borriello, Enrico

    2013-04-01

    Neutrino oscillations in the Earth matter may introduce peculiar modulations in the supernova (SN) neutrino spectra. The detection of this effect has been proposed as diagnostic tool for the neutrino mass hierarchy. We perform an updated study on the observability of this effect at large next-generation underground detectors (i.e., 0.4 Mton water Cherenkov, 50 kton scintillation and 100 kton liquid Argon detectors) based on neutrino fluxes from state-of-the-art SN simulations and accounting for statistical fluctuations via Montecarlo simulations. Since the average energies predicted by recent simulations are lower than previously expected and a tendency towards the equalization of the neutrino fluxes appears during the SN cooling phase, the detection of the Earth matter effect will be more challenging than expected from previous studies. We find that none of the proposed detectors shall be able to detect the Earth modulation for the neutrino signal of a typical galactic SN at 10 kpc. It should be observable in a 100 kton liquid Argon detector for a SN at few kpc and all three detectors would clearly see the Earth signature for very close-by stars only (d˜200 pc).

  13. 5f delocalization-induced suppression of quadrupolar order in U(Pd1-xPtx)₃

    SciTech Connect

    Walker, H. C.; Le, M. D.; McEwen, K. A.; Bleckmann, M.; Süllow, S.; Mazzoli, C.; Wilkins, S. B.; Fort, D.

    2011-12-27

    We present bulk magnetic and transport measurements and x-ray resonant scattering measurements on U(Pd1-xPtx)₃ for x=0.005 and 0.01, which demonstrate the high sensitivity of the quadrupolar order in the canonical antiferroquadrupolar ordered system UPd₃ to doping with platinum. Bulk measurements for x=0.005 reveal behavior similar to that seen in UPd₃, albeit at a lower temperature, and x-ray resonant scattering provides evidence of quadrupolar order described by the Qxy order parameter. In contrast, bulk measurements reveal only an indistinct transition in x=0.01, consistent with the observation of short-range quadrupolar order in our x-ray resonant scattering results.

  14. Effects of rare-earth co-doping on the local structure of rare-earth phosphate glasses using high and low energy X-ray diffraction.

    PubMed

    Cramer, Alisha J; Cole, Jacqueline M; FitzGerald, Vicky; Honkimaki, Veijo; Roberts, Mark A; Brennan, Tessa; Martin, Richard A; Saunders, George A; Newport, Robert J

    2013-06-14

    Rare-earth co-doping in inorganic materials has a long-held tradition of facilitating highly desirable optoelectronic properties for their application to the laser industry. This study concentrates specifically on rare-earth phosphate glasses, (R2O3)x(R'2O3)y(P2O5)(1-(x+y)), where (R, R') denotes (Ce, Er) or (La, Nd) co-doping and the total rare-earth composition corresponds to a range between metaphosphate, RP3O9, and ultraphosphate, RP5O14. Thereupon, the effects of rare-earth co-doping on the local structure are assessed at the atomic level. Pair-distribution function analysis of high-energy X-ray diffraction data (Q(max) = 28 Å(-1)) is employed to make this assessment. Results reveal a stark structural invariance to rare-earth co-doping which bears testament to the open-framework and rigid nature of these glasses. A range of desirable attributes of these glasses unfold from this finding; in particular, a structural simplicity that will enable facile molecular engineering of rare-earth phosphate glasses with 'dial-up' lasing properties. When considered together with other factors, this finding also demonstrates additional prospects for these co-doped rare-earth phosphate glasses in nuclear waste storage applications. This study also reveals, for the first time, the ability to distinguish between P-O and P[double bond, length as m-dash]O bonding in these rare-earth phosphate glasses from X-ray diffraction data in a fully quantitative manner. Complementary analysis of high-energy X-ray diffraction data on single rare-earth phosphate glasses of similar rare-earth composition to the co-doped materials is also presented in this context. In a technical sense, all high-energy X-ray diffraction data on these glasses are compared with analogous low-energy diffraction data; their salient differences reveal distinct advantages of high-energy X-ray diffraction data for the study of amorphous materials.

  15. The association of coronal mass ejections with their effects near the Earth

    NASA Astrophysics Data System (ADS)

    Schwenn, R.; dal Lago, A.; Huttunen, E.; Gonzalez, W. D.

    2005-03-01

    To this day, the prediction of space weather effects near the Earth suffers from a fundamental problem: The radial propagation speed of "halo" CMEs (i.e. CMEs pointed along the Sun-Earth-line that are known to be the main drivers of space weather disturbances) towards the Earth cannot be measured directly because of the unfavorable geometry. From inspecting many limb CMEs observed by the LASCO coronagraphs on SOHO we found that there is usually a good correlation between the radial speed and the lateral expansion speed Vexp of CME clouds. This latter quantity can also be determined for earthward-pointed halo CMEs. Thus, Vexp may serve as a proxy for the otherwise inaccessible radial speed of halo CMEs. We studied this connection using data from both ends: solar data and interplanetary data obtained near the Earth, for a period from January 1997 to 15 April 2001. The data were primarily provided by the LASCO coronagraphs, plus additional information from the EIT instrument on SOHO. Solar wind data from the plasma instruments on the SOHO, ACE and Wind spacecraft were used to identify the arrivals of ICME signatures. Here, we use "ICME" as a generic term for all CME effects in interplanetary space, thus comprising not only ejecta themselves but also shocks as well. Among 181 front side or limb full or partial halo CMEs recorded by LASCO, on the one hand, and 187 ICME events registered near the Earth, on the other hand, we found 91 cases where CMEs were uniquely associated with ICME signatures in front of the Earth. Eighty ICMEs were associated with a shock, and for 75 of them both the halo expansion speed Vexp and the travel time Ttr of the shock could be determined. The function Ttr=203-20.77*ln (Vexp fits the data best. This empirical formula can be used for predicting further ICME arrivals, with a 95% error margin of about one day. Note, though, that in 15% of comparable cases, a full or partial halo CME does not cause any ICME signature at Earth at all; every

  16. New Models of Water Delivery To Earth: The Effects of Ice Longevity and Collisional Water Transport

    NASA Astrophysics Data System (ADS)

    Maindl, Thomas I.; Haghighipour, Nader

    2016-10-01

    It is widely accepted that the vast majority of Earth's water was delivered to its accretion zone by water-carrying planetesimals and planetary embryos from the outer regions of the asteroid belt while Earth was still forming. Modern simulations of the formation of terrestrial planets show this process with high resolution. However, their treatment of the actual delivery of water is still rudimentary assuming that a water-carrying object will maintain all its water content during its journey from its original orbit to the accretion zone of Earth. Models of the ice longevity have, however, shown that the water-ice may not stay intact, and asteroids and planetary embryos may lose some of their original water in form of ice sublimation during the dynamical evolution of these bodies. Also, collisions among these bodies while on their journey to Earth's accretion zone will result in the loss of large amounts of their water. These effects could be especially important during the formation of terrestrial planets as this process takes tens to hundreds of millions of years. We have developed a more accurate model in which the sublimation of ice during the process of the scattering of icy asteroids and planetary embryos into the accretion zone of Earth is taken into account. Our model includes two different modes of handling ice sublimation, one for sub-surface water and one for deeper ice. We also estimate water loss and retention during collisions which depends on the physical and dynamical parameters of the impacts. The results of our simulations put stringent constraints on the initial water distribution in the protoplanetary disk, the location of snowline, and the contribution of water from the primordial nebula to the final water budget of Earth. In this poster, we will present the results of our new simulations and discuss their implications for models of solar system formation and dynamics.

  17. Effect of Oxygen Enrichment in Propane Laminar Diffusion Flames under Microgravity and Earth Gravity Conditions

    NASA Astrophysics Data System (ADS)

    Bhatia, Pramod; Singh, Ravinder

    2017-01-01

    Diffusion flames are the most common type of flame which we see in our daily life such as candle flame and match-stick flame. Also, they are the most used flames in practical combustion system such as industrial burner (coal fired, gas fired or oil fired), diesel engines, gas turbines, and solid fuel rockets. In the present study, steady-state global chemistry calculations for 24 different flames were performed using an axisymmetric computational fluid dynamics code (UNICORN). Computation involved simulations of inverse and normal diffusion flames of propane in earth and microgravity condition with varying oxidizer compositions (21, 30, 50, 100 % O2, by mole, in N2). 2 cases were compared with the experimental result for validating the computational model. These flames were stabilized on a 5.5 mm diameter burner with 10 mm of burner length. The effect of oxygen enrichment and variation in gravity (earth gravity and microgravity) on shape and size of diffusion flames, flame temperature, flame velocity have been studied from the computational result obtained. Oxygen enrichment resulted in significant increase in flame temperature for both types of diffusion flames. Also, oxygen enrichment and gravity variation have significant effect on the flame configuration of normal diffusion flames in comparison with inverse diffusion flames. Microgravity normal diffusion flames are spherical in shape and much wider in comparison to earth gravity normal diffusion flames. In inverse diffusion flames, microgravity flames were wider than earth gravity flames. However, microgravity inverse flames were not spherical in shape.

  18. Ultrahigh-field NMR spectroscopy of quadrupolar transition metals: 55Mn NMR of several solid manganese carbonyls.

    PubMed

    Ooms, Kristopher J; Feindel, Kirk W; Terskikh, Victor V; Wasylishen, Roderick E

    2006-10-16

    55Mn NMR spectra acquired at 21.14 T (nu(L)(55Mn) = 223.1 MHz) are presented and demonstrate the advantages of using ultrahigh magnetic fields for characterizing the chemical shift tensors of several manganese carbonyls: eta5-CpMn(CO)3, Mn2(CO)10, and (CO)5MnMPh3 (M = Ge, Sn, Pb). For the compounds investigated, the anisotropies of the manganese chemical shift tensors are less than 250 ppm except for eta5-CpMn(CO)3, which has an anisotropy of 920 ppm. At 21.14 T, one can excite the entire m(I) = 1/2 <--> m(I) = -1/2 central transition of eta5-CpMn(CO)3, which has a breadth of approximately 700 kHz. The breadth arises from second-order quadrupolar broadening due to the 55Mn quadrupolar coupling constant of 64.3 MHz, as well as the anisotropic shielding. Subtle variations in the electric field gradient tensors at the manganese are observed for crystallographically unique sites in two of the solid pentacarbonyls, resulting in measurably different C(Q) values. MQMAS experiments are able to distinguish four magnetically unique Mn sites in (CO)(5)MnPbPh3, each with slightly different values of delta(iso), C(Q), and eta(Q).

  19. Integrated Computational Protocol for Analyzing Quadrupolar Splittings from Natural Abundance Deuterium NMR Spectra in (Chiral) Oriented Media.

    PubMed

    Navarro-Vazquez, Armando; Berdagué, Philippe; Lesot, Philippe Georges Julien

    2017-03-03

    Despite its low natural abundance, deuterium NMR in weakly oriented (chiral) solvents gives easy access to deuterium residual quadrupolar couplings (2H-RQCs), which are formally equivalent to one-bond 1DCH (13C-1H)-RDCs for calculation of the Saupe order matrix, furnishing similar information to study molecular structure and orientational behavior. In addition, the quadrupolar interaction is one order of magnitude larger than the dipolar interaction, making 2H-RQC analysis much more sensitive tool for structural analysis. Subtle structural differences as well as tiny differences in the molecular alignment of different enantiomers in chiral aligning media can be detected. In order to promote this approach towards organic chemists interested in exploiting the analytical advantages of anisotropic, natural abundance deuterium NMR (NAD NMR), we describe a 2H-RQC/DFT-based integrated computational protocol for the evaluation of the order parameters of aligned solutes via singular value decomposition. Examples of 2H-RQC-assisted analysis of chiral and prochiral molecules dissolved in various polypeptide lyotropic chiral liquid crystals are reported. They illustrate the power of this hyphenated approach and in particular to understand the alignment processes and the role of molecular shape in the ordering mechanism through the determination of inter-tensor angles between alignment tensors and inertia tensors.

  20. The interplay of the crystalline electric field and quadrupolar interactions in the spontaneous magnetic phases of DyIn3

    NASA Astrophysics Data System (ADS)

    Galéra, R. M.; Sole, E.; Amara, M.; Morin, P.; Burlet, P.; Murani, A. P.

    2003-09-01

    DyIn3 orders at TN = 20 K and undergoes a second spontaneous magnetic transition at 16.5 K. From bulk magnetization measurements, performed on a single crystal along the three main axes of the cubic AuCu3-type structure, the magnetic phase diagrams have been established. The crystalline electric field (CEF) scheme, in the paramagnetic phase, and the magnetic structures of the spontaneous and low field-induced phases have been probed by neutron techniques. All the magnetic phases studied are found to be multiple q with q belonging to the langle1/2, 1/2, 0rangle star. In the low temperature phase (T < 16.5 K) the structure is double q with moments along twofold axes, whereas above 16.5 K it becomes triple q with moments along threefold axes. The analysis of the experimental results within the periodic molecular field model leads to a coherent interpretation of the spontaneous magnetic transitions, mainly driven by bilinear exchange and CEF interactions. Though the existence of quadrupolar interactions is definitively proved by the stabilization of multiple q magnetic structures, quadrupolar coefficients are found to be one order of magnitude smaller than those previously reported for NdIn3 and TbIn3.

  1. [Effects of arbuscular mycorrhizal fungi on the growth and rare earth elements uptake of soybean grown in rare earth mine tailings].

    PubMed

    Guo, Wei; Zhao, Ren-xin; Zhao, Wen-jing; Fu, Rui-ying; Guo, Jiang-yuan; Zhang, Jun

    2013-05-01

    A greenhouse pot experiment was conducted to investigate the influence of arbuscular mycorrhizal (AM) fungi Glomus versiforme on the plant growth, nutrient uptake, C: N: P stoichiometric, uptake of heavy metals and rare earth elements by soybean (Glycine max) grown in rare earth mine tailings. The aim was to provide a basis for the revegetation of rare earth mine tailings. The results indicated that soybean had a high mycorrhizal colonization and symbiotic associations were successfully established with G. versiforme, with an average rate of approximately 67%. The colonization of G. versiforme significantly promoted the growth of soybean, increased P, K contents, and decreased C: N: P ratios, supporting the growth rate hypothesis. Inoculation with G. versiforme significantly decreased shoots and roots La, Ce, Pr and Nd concentrations of soybean compared to the control treatment. However, inoculation with G. versiforme had no significant effect on the heavy metal concentrations, except for significantly decreased shoot Fe and Cr concentrations and increased root Cd concentrations. The experiment demonstrates that AM fungi have a potential role for soybean to adapt the composite adversity of rare earth tailings and play a positive role in revegetation of rare earth mine tailings. Further studies on the role of AM fungi under natural conditions should be conducted.

  2. Low Earth orbit environmental effects on the space station photovoltaic power generation systems

    NASA Technical Reports Server (NTRS)

    Nahra, Henry K.

    1987-01-01

    A summary of the Low Earth Orbital Environment, its impact on the Photovoltaic Power systems of the space station and the solutions implemented to resolve the environmental concerns or issues are described. Low Earth Orbital Environment (LEO) presents several concerns to the Photovoltaic power systems of the space station. These concerns include atomic oxygen interaction with the polymeric substrate of the solar arrays, ionized environment effects on the array operating voltage, the effects of the meteoroids and debris impacts and penetration through the different layers of the solar cells and their circuits, and the high energy particle and radiation effects on the overall solar array performance. Potential solutions to some of the degrading environmental interactions that will provide the photovoltaic power system of the space station with the desired life are also summarized.

  3. Low earth orbit environmental effects on the Space Station photovoltaic power generation systems

    NASA Technical Reports Server (NTRS)

    Nahra, H. K.

    1988-01-01

    A summary of the low earth orbital environment, its impact on the photovoltaic power systems of the Space Station and the solutions implemented to resolve the environmental concerns or issues are described. Low earth orbital environment (LEO) presents several concerns to the photovoltaic power systems of the Space Station. These concerns include atomic oxygen interaction with the polymeric substrate of the solar arrays, ionized environment effects on the array operating voltage, the effects of the meteoroids and debris impacts and penetration through the different layers of the solar cells and their circuits, and the high energy particle and radiation effects on the overall solar array performance. Potential solutions to some of the degrading environmental interactions that will provide the photovoltaic power system of the Space Station with the desired life are also summarized.

  4. Precambrian climate: The effects of land area and earth's rotation rate

    SciTech Connect

    Jenkins, G.S. ); Marshall, H.G.; Kuhn, W.R. )

    1993-05-20

    The authors present results of model studies using general circulation models of climatic effects of variations in the rotation rate of the earth. These studies are of relevance for the Precambrian times, when the rotation period of the earth was considerably shorter. The authors include in their model studies a number of factors which were left out in previous studies. The rotation rate has a strong effect on atmospheric circulation, as evidenced in the theory of geostrophic turbulence, mid-latitude baroclinic instability, and the Hadley cell. One can expect the contraction of circulation patterns, both horizontally and vertically. This should also impact heat transport, though questions of mean temperature effects are more open, unless one allows cloud cover to vary. The authors put more realistic starting conditions into the model, and also allow clouds and hydrology to have a feedback role to see what impact rotation rates will have on global climate.

  5. Effect of rare earth metal on the spin-orbit torque in magnetic heterostructures

    NASA Astrophysics Data System (ADS)

    Ueda, Kohei; Pai, Chi-Feng; Tan, Aik Jun; Mann, Maxwell; Beach, Geoffrey S. D.

    2016-06-01

    We report the effect of the rare earth metal Gd on current-induced spin-orbit torques (SOTs) in perpendicularly magnetized Pt/Co/Gd heterostructures, characterized using harmonic measurements and spin-torque ferromagnetic resonance (ST-FMR). By varying the Gd metal layer thickness from 0 nm to 8 nm, harmonic measurements reveal a significant enhancement of the effective fields generated from the Slonczewski-like and field-like torques. ST-FMR measurements confirm an enhanced effective spin Hall angle and show a corresponding increase in the magnetic damping constant with increasing Gd thickness. These results suggest that Gd plays an active role in generating SOTs in these heterostructures. Our finding may lead to spin-orbitronics device application such as non-volatile magnetic random access memory, based on rare earth metals.

  6. What Is the Atmosphere’s Effect on Earth's Surface Temperature?

    NASA Astrophysics Data System (ADS)

    Zeng, Xubin

    2010-04-01

    It is frequently stated in textbooks and scholarly articles that the surface temperature of Earth is 33°C warmer than it would be without the atmosphere and that this difference is due to the greenhouse effect. This Forum shows that the atmosphere effect leads to warming of only 20°C. This new conclusion requires a revision to all of the relevant literature in K-12, undergraduate, and graduate education material and to science papers and reports. The greenhouse effect on Earth's surface temperature is well understood qualitatively and is regarded as basic knowledge about Earth's climate and climate change. The 33°C warming has been used to quantify the greenhouse effect of greenhouse gases, or of greenhouse gases and clouds, in K-12 educational material (e.g., http://epa.gov/climatechange/kids/greenhouse.html), undergraduate freshman introductory textbooks on weather and climate [e.g., Ahrens, 2008], and graduate textbooks on climate [e.g., Peixoto and Oort, 1992]. Some textbooks and various other publications have less stringently attributed the warming to the greenhouse effect [e.g., Wallace and Hobbs, 2006; Le Treut et al., 2007; American Meteorological Society, 2000].

  7. Co-Seismic Mass Dislocation and Its Effect on Earth's Rotation and Gravity

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    1999-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results. The calculation uses the normal mode summation scheme, applied to 15,814 major earthquakes that occurred during 1976-1998, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J(sub 2) and J(sub 22) while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards about 140 degree E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

  8. Co-Seismic Mass Displacement and its Effect on Earth's Rotation and Gravity

    NASA Technical Reports Server (NTRS)

    Chao, B. F.; Gross, R. S.

    2004-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) displacements in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field. The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross. The calculation uses the normal mode summation scheme, applied to over twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Centroid Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies, conspiring to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards approx. 140 deg.E, roughly opposite to the observed polar drift direction. Currently, the Gravity Recovery And Climate Experiment (GRACE) is measuring the time-variable gravity to high degree and order with unprecedented accuracy. Our results show that great earthquakes such as the 1960 Chilean or 1964 Alaskan events cause gravitational field changes that are large enough to be detected by GRACE.

  9. Co-Seismic Mass Dislocation and its Effect on Earth's Rotation and Gravity

    NASA Technical Reports Server (NTRS)

    Chao, B. F.; Gross, R. S.

    2002-01-01

    Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the shaking that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross (1987). The calculation uses the normal mode summation scheme, applied to nearly twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to nudge the Earth rotation pole towards approximately 140 degrees E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

  10. The effects of refraction on transit transmission spectroscopy: application to Earth-like exoplanets

    SciTech Connect

    Misra, Amit; Meadows, Victoria; Crisp, Dave

    2014-09-01

    We quantify the effects of refraction in transit transmission spectroscopy on spectral absorption features and on temporal variations that could be used to obtain altitude-dependent spectra for planets orbiting stars of different stellar types. We validate our model against altitude-dependent transmission spectra of the Earth from ATMOS and against lunar eclipse spectra from Pallé et al. We perform detectability studies to show the potential effects of refraction on hypothetical observations of Earth analogs with the James Webb Space Telescope NIRSPEC. Due to refraction, there will be a maximum tangent pressure level that can be probed during transit for each given planet-star system. We show that because of refraction, for an Earth-analog planet orbiting in the habitable zone of a Sun-like star only the top 0.3 bars of the atmosphere can be probed, leading to a decrease in the signal-to-noise ratio (S/N) of absorption features by 60%, while for an Earth-analog planet orbiting in the habitable zone of an M5V star it is possible to probe almost the entire atmosphere with minimal decreases in S/N. We also show that refraction can result in temporal variations in the transit transmission spectrum which may provide a way to obtain altitude-dependent spectra of exoplanet atmospheres. Additionally, the variations prior to ingress and subsequent to egress provide a way to probe pressures greater than the maximum tangent pressure that can be probed during transit. Therefore, probing the maximum range of atmospheric altitudes, and in particular the near-surface environment of an Earth-analog exoplanet, will require looking at out-of-transit refracted light in addition to the in-transit spectrum.

  11. Spectral Characteristic of Tholin Produced from Possible Early Earth Atmospheres and its Role in Antigreenhouse Effect on Early Earth

    NASA Technical Reports Server (NTRS)

    Khare, B. N.; Imanaka, H.; Wilhite, P.; McKay, C.; Bakes, E.; Cruikshank, D. P.; Arakawa, E. T.

    2003-01-01

    We have produced organic material simulating a methane photochemical haze in a CO2- rich atmosphere of the early Earth by irradiating gas mixtures in an inductively coupled cold plasma chamber with pressure approx. 0.25 mbar at 100 W total power. The flow rate was 24 cm3 min. We added progressively higher levels of CH, by combining gas mixtures of N2/CH4 (9/1) and N2/CO2 (9/1) to change the ratio of CH4/CO2. Tholin was accumulated for 5 hours in each experiment; the onset of tholin formation is in the range CH4/CO2 = 0.5 to 1. As the mixing ratio of CH, is increased, the production rate of the brownish tholin film increases. IR spectra showed the C-H and N-H bands similar to that of Titan tholin and closely resemble Titan tholin made at 0.13 mbar pressure. A decrease in the CH bonds on decreasing CH4/CO2 is noted. Ether bands (-(2-O-C) were tentatively detected, but no detectable carbonyl (C=O) band was found. The absorption in the UV region for the early Earth tholin is found to be substantially greater than the Titan tholin. Quantitative values of the optical constants of early Earth tholin are currently being measured.

  12. Effect of Earth and Mars departure delays on human missions to Mars

    NASA Astrophysics Data System (ADS)

    Desai, Prasun N.; Tartabini, Paul V.

    1993-08-01

    This study determines the impact on the initial mass in low-Earth orbit (IMLEO) for delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep space maneuver (DSM) is attempted to alleviate the IMLEO penalties. Three different classes of missions are analyzed using chemical and nuclear thermal propulsion systems in the 2000-2025 time-frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction class missions have the highest IMLEO penalties, upwards of 432.4 mt and 1977.3 mt, respectively. Conjunction class missions, on the other hand, tend to be insensitive to Mars and Earth delays having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties as compared to chemical propulsion. The use of a DSM is found not to have a significant impact on reducing the IMLEO penalties. Through this investigation, the effect of off-nominal departure conditions on the overall mission (i.e., IMLEO) can be gained, enabling mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design process of a Mars transfer vehicle.

  13. Effects of the same CIR on the plasma environment of Venus, Earth and Mars

    NASA Astrophysics Data System (ADS)

    Opitz, A.; Witasse, O.; Svedhem, H.; Sauvaud, J.-A.; Fedorov, A.

    2013-09-01

    During the recent solar activity minimum the solar wind streams were very persistent, even after a few solar rotations the global solar wind properties were unchanged. The compression regions due to the fast stream - slow stream interaction were sweeping through the ecliptic plane without large longitudinal alterations, these are named corotating interaction regions (CIR). Their persistence allows the comparison of the effects of the same CIR on the different terrestrial planets. We investigated the time period in January and February 2007, when the twin solar spacecraft STEREO were still nearby Earth observing simultaneously the solar wind and the terrestrial magnetotail. When considering the solar rotation and the corotating solar wind structures, Venus was ~10 days ahead Earth, while Mars ~10 days behind. For this reason, the Venus Express in-situ plasma and magnetic field measurements were shifted by such a timelag to Earth orbit, and respectively the Mars Express observations in order to find the corresponding CIRs. Since the investigated three planets have different magnetic characteristics, their response to the CIR passage is expected to be different. We find energetic particle bursts escaping from the magnetized Earth and the unmagnetized planets Venus and Mars have increased ion escape rates.

  14. Effect of Earth and Mars departure delays on human missions to Mars

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Tartabini, Paul V.

    1993-01-01

    This study determines the impact on the initial mass in low-Earth orbit (IMLEO) for delaying departure from Mars and Earth by 5, 15, and 30 days, once a nominal mission to Mars has been selected. Additionally, the use of a deep space maneuver (DSM) is attempted to alleviate the IMLEO penalties. Three different classes of missions are analyzed using chemical and nuclear thermal propulsion systems in the 2000-2025 time-frame: opposition, conjunction, and fast-transfer conjunction. The results indicate that Mars and Earth delays can lead to large IMLEO penalties. Opposition and fast-transfer conjunction class missions have the highest IMLEO penalties, upwards of 432.4 mt and 1977.3 mt, respectively. Conjunction class missions, on the other hand, tend to be insensitive to Mars and Earth delays having IMLEO penalties under 103.5 mt. As expected, nuclear thermal propulsion had significantly lower IMLEO penalties as compared to chemical propulsion. The use of a DSM is found not to have a significant impact on reducing the IMLEO penalties. Through this investigation, the effect of off-nominal departure conditions on the overall mission (i.e., IMLEO) can be gained, enabling mission designers to incorporate the influence of off-nominal departure conditions of the interplanetary trajectory in the overall conceptual design process of a Mars transfer vehicle.

  15. Earth remote sensing as an effective tool for the development of advanced innovative educational technologies

    NASA Astrophysics Data System (ADS)

    Mayorova, Vera; Mayorov, Kirill

    2009-11-01

    Current educational system is facing a contradiction between the fundamentality of engineering education and the necessity of applied learning extension, which requires new methods of training to combine both academic and practical knowledge in balance. As a result there are a number of innovations being developed and implemented into the process of education aimed at optimizing the quality of the entire educational system. Among a wide range of innovative educational technologies there is an especially important subset of educational technologies which involve learning through hands-on scientific and technical projects. The purpose of this paper is to describe the implementation of educational technologies based on small satellites development as well as the usage of Earth remote sensing data acquired from these satellites. The increase in public attention to the education through Earth remote sensing is based on the concern that although there is a great progress in the development of new methods of Earth imagery and remote sensing data acquisition there is still a big question remaining open on practical applications of this kind of data. It is important to develop the new way of thinking for the new generation of people so they understand that they are the masters of their own planet and they are responsible for its state. They should desire and should be able to use a powerful set of tools based on modern and perspective Earth remote sensing. For example NASA sponsors "Classroom of the Future" project. The Universities Space Research Association in United States provides a mechanism through which US universities can cooperate effectively with one another, with the government, and with other organizations to further space science and technology, and to promote education in these areas. It also aims at understanding the Earth as a system and promoting the role of humankind in the destiny of their own planet. The Association has founded a Journal of Earth System

  16. Possible Effect of the Earth's Inertial Induction on the Orbital Decay of LAGEOS

    NASA Astrophysics Data System (ADS)

    Dey, Ujjal; Kar, Samanwita; Ghosh, Amitabha

    2016-09-01

    The theory of velocity dependent inertial induction, based upon extended Mach's principle, has been able to generate many interesting results related to celestial mechanics and cosmological problems. Because of the extremely minute magnitude of the effect its presence can be detected through the motion of accurately observed bodies like Earth satellites. LAGEOS I and II are medium altitude satellites with nearly circular orbits. The motions of these satellites are accurately recorded and the past data of a few decades help to test many theories including the general theory of relativity. Therefore, it is hoped that the effect of the Earth's inertial induction can have any detectable effect on the motion of these satellites. It is established that the semi-major axis of LAGEOS I is decreasing at the rate of 1.3 mm/d. As the atmospheric drag is negligible at that altitude, a proper explanation of the secular change has been wanting, and, therefore, this paper examines the effect of the Earth's inertial induction effect on LAGEOS I. Past researches have established that Yarkovsky thermal drag, charged and neutral particle drag might be the possible mechanisms for this orbital decay. Inertial induction is found to generate a perturbing force that results in 0.33 mm/d decay of the semi major axis. Some other changes are also predicted and the phenomenon also helps to explain the observed changes in the orbits of a few other satellites. The results indicate the feasibility of the theory of inertial induction i.e. the dynamic gravitation phenomenon of the Earth on its satellites as a possible partial cause for orbital decay.

  17. Effects of inherent alkali and alkaline earth metallic species on biomass pyrolysis at different temperatures.

    PubMed

    Hu, Song; Jiang, Long; Wang, Yi; Su, Sheng; Sun, Lushi; Xu, Boyang; He, Limo; Xiang, Jun

    2015-09-01

    This work aimed to investigate effects of inherent alkali and alkaline earth metallic species (AAEMs) on biomass pyrolysis at different temperatures. The yield of CO, H2 and C2H4 was increased and that of CO2 was suppressed with increasing temperature. Increasing temperature could also promote depolymerization and aromatization reactions of active tars, forming heavier polycyclic aromatic hydrocarbons, leading to decrease of tar yields and species diversity. Diverse performance of inherent AAEMs at different temperatures significantly affected the distribution of pyrolysis products. The presence of inherent AAEMs promoted water-gas shift reaction, and enhanced the yield of H2 and CO2. Additionally, inherent AAEMs not only promoted breakage and decarboxylation/decarbonylation reaction of thermally labile hetero atoms of the tar but also enhanced thermal decomposing of heavier aromatics. Inherent AAEMs could also significantly enhance the decomposition of levoglucosan, and alkaline earth metals showed greater effect than alkali metals.

  18. Thermal evolution of the earth - Effects of volatile exchange between atmosphere and interior

    NASA Technical Reports Server (NTRS)

    Mcgovern, Patrick J.; Schubert, Gerald

    1989-01-01

    The thermal history of the earth is investigated using a parameterized model of mantle convection, that includes the effects of volatile exchange between the mantle and the surface reservoir and the softening of the mantle by the dissolved volatiles. The mantle degassing rate is taken to be directly proportional to the rate of seafloor spreading which depends on the mantle heat flow. It is shown that the dependence of the mantle viscosity on the volatile content has important effects on the thermal evolution of planetary interiors and the evolution of planetary atmospheres. Degassing is compensated by an increase in temperature, while regassing is compensated by a decrease in temperature. Reasonable degassing scenarios can account for an early rapid formation of the earth's atmosphere inferred from noble gas abundances.

  19. Dynamic effect of metro-induced vibration on the rammed earth base of the Bell Tower.

    PubMed

    Lai, Jinxing; Niu, Fangyuan; Wang, Ke; Chen, Jianxun; Qiu, Junling; Fan, Haobo; Hu, Zhinan

    2016-01-01

    Xi'an Bell Tower (the Bell Tower) is a state-level ancient relic in China. The vibration caused by metro will exert adverse effect on the Bell Tower. This paper aims at presenting 3D-FEM models to predict the peak period velocity (PPV) of rammed earth base when the metro passing through the Bell Tower. The calculation results are compared with those of field test. Both results were found to be in good agreement. Furthermore, the results indicated that the effect of shock absorption measures is significant. The shock absorption tracks can obviously decrease the vibration of the Bell Tower, and the maximum decrease of PPV of the rammed earth base is 78.91 %. The proposed prediction has the potential to be developed as a decision and management tool for the evaluation of the risk associated with the influence of vibration caused by metro on buildings in urban areas.

  20. Effect of Rheology on Mantle Dynamics and Plate Tectonics in Super-Earths

    NASA Astrophysics Data System (ADS)

    Tackley, P. J.; Ammann, M. W.; Brodholt, J. P.; Dobson, D. P.; Valencia, D. C.

    2011-12-01

    The discovery of extra-solar "super-Earth" planets with sizes up to twice that of Earth has prompted interest in their possible lithosphere and mantle dynamics and evolution. Simple scalings [1,2] suggest that super-Earths are more likely than an equivalent Earth-sized planet to be undergoing plate tectonics. Generally, viscosity and thermal conductivity increase with pressure while thermal expansivity decreases, resulting in lower convective vigor in the deep mantle, which, if extralopated to the largest super-Earths might, according to conventional thinking, result a very low effective Rayleigh number in their deep mantles and possibly no convection there. Here we evaluate this. (i) As the mantle of a super-Earth is made mostly of post-perovskite we here extend the density functional theory (DFT) calculations of post-perovskite activation enthalpy of [3] to a pressure of 1 TPa. The activation volume for diffusion creep becomes very low at very high pressure, but nevertheless for the largest super-Earths the viscosity along an adiabat may approach 10^30 Pa s in the deep mantle, which would be too high for convection. (ii) We use these DFT-calculated values in numerical simulations of mantle convection and lithosphere dynamics of planets with up to ten Earth masses. The models assume a compressible mantle including depth-dependence of material properties and plastic yielding induced plate-like lithospheric behavior, solved using StagYY [4]. Results confirm the likelihood of plate tectonics and show a novel self-regulation of deep mantle temperature. The deep mantle is not adiabatic; instead internal heating raises the temperature until the viscosity is low enough to facilitate convective loss of the radiogenic heat, which results in a super-adiabatic temperature profile and a viscosity increase with depth of no more than ~3 orders of magnitude, regardless of what is calculated for an adiabat. It has recently been argued [5] that at very high pressures, deformation

  1. Preliminary Results on the Gravitational Slingshot Effect and the Population of Hyperbolic Meteoroids at Earth

    NASA Technical Reports Server (NTRS)

    Wiegert, P. A.

    2011-01-01

    Interstellar meteoroids, solid particles arriving from outside our Solar System, are not easily distinguished from local meteoroids. A velocity above the escape velocity of the Sun is often used as an indicator of a possible interstellar origin. We demonstrate that the gravitational slingshot effect, resulting from the passage of local meteoroid near a planet, can produce hyperbolic meteoroids at the Earth s orbit with excess velocities comparable to those expected of interstellar meteoroids.

  2. The effects from high-altitude storm discharges in Earth atmosphere

    NASA Astrophysics Data System (ADS)

    Kozak, L.; Odzimek, A.; Ivchenko, V.; Kozak, P.; Gala, I.; Lapchuk, V.

    2016-06-01

    The regularities of appearance of transient luminous effects in Earth atmosphere and features of their ground-based observations are considered. Using video-observations obtained in the Institution of Geophysics of Poland Academy of Sciences the energy of atmospheric afterglow from these processes in visual wavelength range has been determined. Calibrating curve was plotted using unfocal images of Vega. The star spectrum,atmosphere absorption coefficient and characteristics of the observational camera were used.

  3. The Role of Stereo Projection in Developing an Effective Concluding Earth Science Course

    NASA Astrophysics Data System (ADS)

    Kirkby, K. C.; Morin, P. J.; Finley, F.

    2003-12-01

    Remarkably few students enrolled in introductory earth science courses have any intention of continuing in earth science, and for most students, these classes are often the last science course they will take in their academic careers. These students would be better served, if the course was instead designed to be a 'concluding' science course. One that explicitly provided students with the knowledge they need to become more informed citizens in the global community. The University of Minnesota is attempting to develop a national model of an effective 'concluding' earth science course by integrating three essential approaches: use of regional case studies to increase student comprehension; a comprehensive evaluation of students' prior knowledge, misconceptions and post-instructional knowledge that is woven throughout the project; and, an ambitious use of 'GeoWall' stereo projection systems to facilitate the students' use of maps and data sets and level the classroom playing field with regard to spatial conceptualization. In every discipline there are some critical skills or assessments that serve as conscious or unconscious 'gate-keepers' for progress in that field. In earth science, map interpretation is probably the critical restriction curtailing students' ability to access and explore course concepts. So much of our discipline's information is encoded in maps, that students who are not innately predisposed to understanding maps find it difficult to understand much of the course content and methodology. GeoWall stereo projection systems can reduce the efficiency of this 'gate-keeping' process, allowing students of diverse backgrounds and abilities to understand map data and succeed in the course. In doing so, these systems will not only help increase students' scientific literacy, but may also greatly increase the diversity of students who do go on to consider earth science as a potential career.

  4. Effect of UV Radiation on the Spectral Fingerprints of Earth-like Planets Orbiting M Stars

    NASA Astrophysics Data System (ADS)

    Rugheimer, S.; Kaltenegger, L.; Segura, A.; Linsky, J.; Mohanty, S.

    2015-08-01

    We model the atmospheres and spectra of Earth-like planets orbiting the entire grid of M dwarfs for active and inactive stellar models with Teff = 2300 K to Teff = 3800 K and for six observed MUSCLES M dwarfs with UV radiation data. We set the Earth-like planets at the 1 AU equivalent distance and show spectra from the visible to IR (0.4-20 μm) to compare detectability of features in different wavelength ranges with the James Webb Space Telescope and other future ground- and spaced-based missions to characterize exo-Earths. We focus on the effect of UV activity levels on detectable atmospheric features that indicate habitability on Earth, namely, H2O, O3, CH4, N2O, and CH3Cl. To observe signatures of life—O2/O3 in combination with reducing species like CH4—we find that early and active M dwarfs are the best targets of the M star grid for future telescopes. The O2 spectral feature at 0.76 μm is increasingly difficult to detect in reflected light of later M dwarfs owing to low stellar flux in that wavelength region. N2O, another biosignature detectable in the IR, builds up to observable concentrations in our planetary models around M dwarfs with low UV flux. CH3Cl could become detectable, depending on the depth of the overlapping N2O feature. We present a spectral database of Earth-like planets around cool stars for directly imaged planets as a framework for interpreting future light curves, direct imaging, and secondary eclipse measurements of the atmospheres of terrestrial planets in the habitable zone to design and assess future telescope capabilities.

  5. EFFECT OF UV RADIATION ON THE SPECTRAL FINGERPRINTS OF EARTH-LIKE PLANETS ORBITING M STARS

    SciTech Connect

    Rugheimer, S.; Kaltenegger, L.; Segura, A.; Linsky, J.; Mohanty, S.

    2015-08-10

    We model the atmospheres and spectra of Earth-like planets orbiting the entire grid of M dwarfs for active and inactive stellar models with T{sub eff} = 2300 K to T{sub eff} = 3800 K and for six observed MUSCLES M dwarfs with UV radiation data. We set the Earth-like planets at the 1 AU equivalent distance and show spectra from the visible to IR (0.4–20 μm) to compare detectability of features in different wavelength ranges with the James Webb Space Telescope and other future ground- and spaced-based missions to characterize exo-Earths. We focus on the effect of UV activity levels on detectable atmospheric features that indicate habitability on Earth, namely, H{sub 2}O, O{sub 3}, CH{sub 4}, N{sub 2}O, and CH{sub 3}Cl. To observe signatures of life—O{sub 2}/O{sub 3} in combination with reducing species like CH{sub 4}—we find that early and active M dwarfs are the best targets of the M star grid for future telescopes. The O{sub 2} spectral feature at 0.76 μm is increasingly difficult to detect in reflected light of later M dwarfs owing to low stellar flux in that wavelength region. N{sub 2}O, another biosignature detectable in the IR, builds up to observable concentrations in our planetary models around M dwarfs with low UV flux. CH{sub 3}Cl could become detectable, depending on the depth of the overlapping N{sub 2}O feature. We present a spectral database of Earth-like planets around cool stars for directly imaged planets as a framework for interpreting future light curves, direct imaging, and secondary eclipse measurements of the atmospheres of terrestrial planets in the habitable zone to design and assess future telescope capabilities.

  6. The effect of cloud type on Earth's energy balance - Global analysis

    NASA Technical Reports Server (NTRS)

    Hartmann, Dennis L.; Ockert-Bell, Maureen E.; Michelsen, Marc L.

    1992-01-01

    The role of fractional area coverage by cloud types in the energy balance of the earth is investigated through joint use of International Satellite Cloud Climatology Project (ISCCP) C1 cloud data and Earth Radiation Budget Experiment (ERBE) broadband energy flux data for the one-year period March 1985 through February 1986. Multiple linear regression is used to relate the radiation budget data to the cloud data. Comparing cloud forcing estimates obtained from the ISCCP-ERBE regression with those derived from the ERBE scene identification shows generally good agreement except over snow, in tropical convective regions, and in regions that are either nearly cloudless or always overcast. It is suggested that a substantial fraction of the disagreement in longwave cloud forcing in tropical convective regions is associated with the fact that the ERBE scene identification does not take into account variations in upper-tropospheric water vapor. On a global average basis, low clouds make the largest contribution to the net energy balance of the Earth, because they cover such a large area and because their albedo effect dominates their effect on emitted thermal radiation. High, optically thick clouds can also very effectively reduce the energy balance, however, because their very high albedos overcome their low emission temperatures.

  7. The Earth Exploration Toolbook: Scaffolding Access and Use of Earth Science Data to Promote Effective Inquiry Investigations by Students

    NASA Astrophysics Data System (ADS)

    Ledley, T. S.; Dahlman, L.; McAuliffe, C.; Haddad, N.

    2007-12-01

    The Earth Exploration Toolbook (EET, http://serc.carleton.edu/eet) is an online collection of computer-based Earth science activities. Each activity, or chapter, introduces one or more data sets and an analysis tool that enables users to explore some aspect of the Earth system. Series of step-by-step instructions show users how to 1) access the data and analysis tool and install it if necessary, 2) examine, visualize, and interpret the data, and 3) conduct a data-based investigation using the data and analysis tool. Step-by-step instructions walk users through valid scientific inquiries of the data to produce a map, graph, or other data product. The implicit goal of each chapter though, is to build the skills and confidence of teachers and students to enable them to learn and teach with data. When educators become familiar enough with data and analysis tools, they can adapt the use of data to match their curriculum and their students" abilities. This enables educators to promote a greater use of inquiry into students learning of scientific concepts. EET chapters are rich launching points for inquiry. Embedded open-ended questions ask users to consider various aspects of the data. These questions can begin the process of guided inquiry. The "Going Further" section of each EET chapter provides ideas for independent investigations, using another dataset or employing the same analysis strategy with a different analysis tool. At least one chapter inspired an award-winning high school science fair project. In this session we will examine the components of EET chapters that promote inquiry, describe the use of EET chapters in our teacher professional development programs, and give examples of how these programs have impacted participating teachers" use of data, analysis tools, and inquiry in their teaching.

  8. Spin-orbit coupling in octamers in the spinel sulfide CuIr2S4: Competition between spin-singlet and quadrupolar states and its relevance to remnant paramagnetism

    NASA Astrophysics Data System (ADS)

    Nasu, Joji; Motome, Yukitoshi

    2014-07-01

    We theoretically investigate magnetic properties in the low-temperature phase with the formation of eight-site clusters, octamers, in the spinel compound CuIr2S4. The octamer state was considered to be a spin-singlet state induced by a Peierls instability through the strong anisotropy of d orbitals, the so-called orbital Peierls state. We reexamine this picture by taking into account the spin-orbit coupling, which was ignored in the previous study. We derive a low-energy effective model between jeff=1/2 quasispins on Ir4+ cations in an octamer from the multiorbital Hubbard model with the strong spin-orbit coupling by performing the perturbation expansion from the strong correlation limit. The effective Hamiltonian is in the form of the Kitaev-Heisenberg model but with an additional interaction, a symmetric off-diagonal exchange interaction originating from the perturbation process including both d-d and d-p-d hoppings. Analyzing the effective Hamiltonian on two sites and the octamer by the exact diagonalization, we find that there is competition between a spin-singlet state and a quadrupolar state. The former singlet state is a conventional one, adiabatically connected to the orbital Peierls state. On the other hand, the latter quadrupolar state is stabilized by the additional interaction, which consists of a linear combination of different total spin momenta along the spin quantization axis. In the competing region, the model exhibits paramagnetic behavior with a renormalized small effective moment at low temperature. This peculiar remnant paramagnetism is not obtained in the Kitaev-Heisenberg model without the additional interaction. Our results renew the picture of the octamer state and provide a scenario for the intrinsic paramagnetic behavior recently observed in a muon spin rotation experiment [K. M. Kojima et al., Phys. Rev. Lett. 112, 087203 (2014)]., 10.1103/PhysRevLett.112.087203

  9. Compact High Current Rare-Earth Emitter Hollow Cathode for Hall Effect Thrusters

    NASA Technical Reports Server (NTRS)

    Hofer, Richard R. (Inventor); Goebel, Dan M. (Inventor); Watkins, Ronnie M. (Inventor)

    2012-01-01

    An apparatus and method for achieving an efficient central cathode in a Hall effect thruster is disclosed. A hollow insert disposed inside the end of a hollow conductive cathode comprises a rare-earth element and energized to emit electrons from an inner surface. The cathode employs an end opening having an area at least as large as the internal cross sectional area of the rare earth insert to enhance throughput from the cathode end. In addition, the cathode employs a high aspect ratio geometry based on the cathode length to width which mitigates heat transfer from the end. A gas flow through the cathode and insert may be impinged by the emitted electrons to yield a plasma. One or more optional auxiliary gas feeds may also be employed between the cathode and keeper wall and external to the keeper near the outlet.

  10. Pulse-assisted homonuclear dipolar recoupling of half-integer quadrupolar spins in magic-angle spinning NMR

    NASA Astrophysics Data System (ADS)

    Edén, Mattias; Annersten, Hans; Zazzi, Åsa

    2005-07-01

    We demonstrate numerically and experimentally that zero-quantum homonuclear dipolar recoupling techniques employing rotor-synchronized 180° pulses, previously introduced for spin-1/2 applications, are useful also for magnetization transfers between half-integer quadrupolar nuclei in rotating solids. The recoupling sequences are incorporated as mixing periods in two-dimensional experimental protocols, that correlate either single-quantum coherences of coupled spins, or triple-quantum with single-quantum coherences for improving spectral resolution. We present 23Na and 27Al NMR experiments on powders of sodium sulphite [Na 2SO 3], YAG [Y 3Al 5O 12] and a synthetic chlorite mineral [Mg 4.5Al 3Si 2.5O 10(OH) 8].

  11. SIMQUADNMR: a program for simulation and interpretation of multiple quantum-filtered NMR spectra of quadrupolar nuclei.

    PubMed

    D'Amelio, Nicola; Gaggelli, Elena; Molteni, Elena; Valensin, Gianni

    2005-01-01

    In this paper, we present a computer program which simulates NMR multiple quantum-filtered spectra of quadrupolar nuclei as a function of physical parameters, of the type of experiment and experimental conditions. The program works by solving relaxation theory equations for the given system, and it can be useful in order to plan the ideal conditions to set up specific experiments or to give a physical interpretation of experimental results. The program allows to independently follow the dependence of individual coherences and relaxation rates as a function of up to 50 parameters regarding the physical properties of the system under investigation, sample conditions and instrumental setup making it an helpful tool also for teaching purposes.

  12. Effects on optical systems from interactions with oxygen atoms in low earth orbits

    NASA Technical Reports Server (NTRS)

    Peters, P. N.; Swann, J. T.; Gregory, J. C.

    1986-01-01

    Modifications of material surface properties due to interactions with ambient atomic oxygen have been observed on surfaces facing the orbital direction in low earth orbits. Some effects are very damaging to surface optical properties while some are more subtle and even beneficial. Most combustible materials are heavily etched, and some coatings, such as silver and osmium, are seriously degraded or removed as volatile oxides. The growth of oxide films on metals and semiconductors considered stable in dry air was measured. Material removal, surface roughness, reflectance, and optical densities are reported. Effects of temperature, contamination, and overcoatings are noted.

  13. Test of general relativity and measurement of the lense-thirring effect with two earth satellites

    PubMed

    Ciufolini; Pavlis; Chieppa; Fernandes-Vieira; Perez-Mercader

    1998-03-27

    The Lense-Thirring effect, a tiny perturbation of the orbit of a particle caused by the spin of the attracting body, was accurately measured with the use of the data of two laser-ranged satellites, LAGEOS and LAGEOS II, and the Earth gravitational model EGM-96. The parameter &mgr;, which measures the strength of the Lense-Thirring effect, was found to be 1.1 +/- 0.2; general relativity predicts &mgr; identical with 1. This result represents an accurate test and measurement of one of the fundamental predictions of general relativity, that the spin of a body changes the geometry of the universe by generating space-time curvature.

  14. Empirical determination of the effects of clouds on the Earth's Radiation Budget over the Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Ziskin, Daniel; Strobel, Darrell F.

    1992-01-01

    The main objectives of this research has been to learn how clouds interact with the Earth's Radiation Budget (ERB). This broad goal has been approached in three distinct ways. The first has been to analyze the direct effect cloud amount has on the radiative components of the ERB. The second has been to investigate the indirect effects clouds and water vapor may have on the climate as a feedback mechanism. And finally an attempt has been made to simulate the findings in a simple radiative-convective climate model. This report will summarize these three phases of the research.

  15. Solar and terrestrial physics. [effects of solar activities on earth environment

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The effects of solar radiation on the near space and biomental earth, the upper atmosphere, and the magnetosphere are discussed. Data obtained from the OSO satellites pertaining to the solar cycle variation of extreme ultraviolet (EUV) radiation are analyzed. The effects of solar cycle variation of the characteristics of the solar wind are examined. The fluid mechanics of shock waves and the specific relationship to the characteristics of solar shock waves are investigated. The solar and corpuscular heating of the upper atmosphere is reported based on the findings of the AEROS and NATE experiments. Seasonal variations of the upper atmosphere composition are plotted based on OGO-6 mass spectrometer data.

  16. On the Effects of the Evolution of Microbial Mats and Land Plants on the Earth as a Planet. Photometric and Spectroscopic Light Curves of Paleo-Earths

    NASA Astrophysics Data System (ADS)

    Sanromá, E.; Pallé, E.; García Munõz, A.

    2013-04-01

    Understanding the spectral and photometric variability of the Earth and the rest of the solar system planets has become of utmost importance for the future characterization of rocky exoplanets. As this is not only interesting at present times but also along the planetary evolution, we studied the effect that the evolution of microbial mats and plants over land has had on the way our planet looks from afar. As life evolved, continental surfaces changed gradually and non-uniformly from deserts through microbial mats to land plants, modifying the reflective properties of the ground and most likely the distribution of moisture and cloudiness. Here, we used a radiative transfer model of the Earth, together with geological paleo-records of the continental distribution and a reconstructed cloud distribution, to simulate the visible and near-IR radiation reflected by our planet as a function of Earth's rotation. We found that the evolution from deserts to microbial mats and to land plants produces detectable changes in the globally averaged Earth's reflectance. The variability of each surface type is located in different bands and can induce reflectance changes of up to 40% in period of hours. We conclude that by using photometric observations of an Earth-like planet at different photometric bands it would be possible to discriminate between different surface types. While recent literature proposes the red-edge feature of vegetation near 0.7 μm as a signature for land plants, observations in near-IR bands can be equally or even better suited for this purpose.

  17. ON THE EFFECTS OF THE EVOLUTION OF MICROBIAL MATS AND LAND PLANTS ON THE EARTH AS A PLANET. PHOTOMETRIC AND SPECTROSCOPIC LIGHT CURVES OF PALEO-EARTHS

    SciTech Connect

    Sanroma, E.; Palle, E.; Garcia Munoz, A.

    2013-04-01

    Understanding the spectral and photometric variability of the Earth and the rest of the solar system planets has become of utmost importance for the future characterization of rocky exoplanets. As this is not only interesting at present times but also along the planetary evolution, we studied the effect that the evolution of microbial mats and plants over land has had on the way our planet looks from afar. As life evolved, continental surfaces changed gradually and non-uniformly from deserts through microbial mats to land plants, modifying the reflective properties of the ground and most likely the distribution of moisture and cloudiness. Here, we used a radiative transfer model of the Earth, together with geological paleo-records of the continental distribution and a reconstructed cloud distribution, to simulate the visible and near-IR radiation reflected by our planet as a function of Earth's rotation. We found that the evolution from deserts to microbial mats and to land plants produces detectable changes in the globally averaged Earth's reflectance. The variability of each surface type is located in different bands and can induce reflectance changes of up to 40% in period of hours. We conclude that by using photometric observations of an Earth-like planet at different photometric bands it would be possible to discriminate between different surface types. While recent literature proposes the red-edge feature of vegetation near 0.7 {mu}m as a signature for land plants, observations in near-IR bands can be equally or even better suited for this purpose.

  18. High-Accuracy Ring Laser Gyroscopes: Earth Rotation Rate and Relativistic Effects

    NASA Astrophysics Data System (ADS)

    Beverini, N.; Di Virgilio, A.; Belfi, J.; Ortolan, A.; Schreiber, K. U.; Gebauer, A.; Klügel, T.

    2016-06-01

    The Gross Ring G is a square ring laser gyroscope, built as a monolithic Zerodur structure with 4 m length on all sides. It has demonstrated that a large ring laser provides a sensitivity high enough to measure the rotational rate of the Earth with a high precision of ΔΩE < 10-8. It is possible to show that further improvement in accuracy could allow the observation of the metric frame dragging, produced by the Earth rotating mass (Lense-Thirring effect), as predicted by General Relativity. Furthermore, it can provide a local measurement of the Earth rotational rate with a sensitivity near to that provided by the international system IERS. The GINGER project is intending to take this level of sensitivity further and to improve the accuracy and the long-term stability. A monolithic structure similar to the G ring laser is not available for GINGER. Therefore the preliminary goal is the demonstration of the feasibility of a larger gyroscope structure, where the mechanical stability is obtained through an active control of the geometry. A prototype moderate size gyroscope (GP-2) has been set up in Pisa in order to test this active control of the ring geometry, while a second structure (GINGERino) has been installed inside the Gran Sasso underground laboratory in order to investigate the properties of a deep underground laboratory in view of an installation of a future GINGER apparatus. The preliminary data on these two latter instruments are presented.

  19. Displacements of the earth's surface due to atmospheric loading - Effects of gravity and baseline measurements

    NASA Technical Reports Server (NTRS)

    Van Dam, T. M.; Wahr, J. M.

    1987-01-01

    Atmospheric mass loads and deforms the earth's crust. By performing a convolution sum between daily, global barometric pressure data and mass loading Green's functions, the time dependent effects of atmospheric loading, including those associated with short-term synoptic storms, on surface point positioning measurements and surface gravity observations are estimated. The response for both an oceanless earth and an earth with an inverted barometer ocean is calculated. Load responses for near-coastal stations are significantly affected by the inclusion of an inverted barometer ocean. Peak-to-peak vertical displacements are frequently 15-20 mm with accompanying gravity perturbations of 3-6 micro Gal. Baseline changes can be as large as 20 mm or more. The perturbations are largest at higher latitudes and during winter months. These amplitudes are consistent with the results of Rabbel and Zschau (1985), who modeled synoptic pressure disturbances as Gaussian functions of radius around a central point. Deformation can be adequately computed using real pressure data from points within about 1000 km of the station. Knowledge of local pressure, alone, is not sufficient. Rabbel and Zschau's hypothesized corrections for these displacements, which use local pressure and the regionally averaged pressure, prove accurate at points well inland but are, in general, inadequate within a few hundred kilometers of the coast.

  20. The Effect of Alkaline Earth Metal on the Cesium Loading of Ionsiv(R) IE-910 and IE-911

    SciTech Connect

    Fondeur, F.F.

    2001-01-16

    This study investigated the effect of variances in alkaline earth metal concentrations on cesium loading of IONSIV(R) IE-911. The study focused on Savannah River Site (SRS) ''average'' solution with varying amounts of calcium, barium and magnesium.

  1. Truncation effects in computing free wobble/nutation modes explored using a simple Earth model

    NASA Astrophysics Data System (ADS)

    Seyed-Mahmoud, Behnam; Rochester, Michael G.; Rogers, Christopher M.

    2017-03-01

    The displacement field accompanying the wobble/nutation of the Earth is conventionally represented by an infinite chain of toroidal and spheroidal vector spherical harmonics, coupled by rotation and ellipticity. Numerical solutions for the eigenperiods require truncation of that chain, and the standard approaches using the linear momentum description (LMD) of deformation during wobble/nutation have truncated it at very low degrees, usually degree 3 or 4, and at most degree 5. The effects of such heavy truncation on the computed eigenperiods have hardly been examined. We here investigate the truncation effects on the periods of the free wobble/nutation modes using a simplified Earth model consisting of a homogeneous incompressible inviscid liquid outer core with a rigid (but not fixed) inner core and mantle. A novel Galerkin method is implemented using a Clairaut coordinate system to solve the classic Poincaré problem in the liquid core and, to close the problem, we use the Lagrangean formulation of the Liouville equation for each of the solid parts of the Earth model. We find that, except for the free inner core nutation (FICN), the periods of the free rotational modes converge rather quickly. The period of the tiltover mode (TOM) is found to excellent accuracy. The computed periods of the Chandler wobble (CW) and free core nutation (FCN) are nearly identical to the values cited in the literature for similar Earth models, but that for the inner core wobble (ICW) is slightly different. Truncation at low-degree harmonics causes the FICN period to fluctuate over a range as large as 90 sd, with different values at different truncation levels. For example, truncation at degree 6 gives a period of 752 sd (almost identical with the value cited in the literature for such an Earth model) but truncation at degree 24 is required to obtain convergence, and the resulting period is 746 ± 1 sd, as more terms are included, with no guarantee that its proximity to earlier values

  2. The influence of earth tides on earth's coordinates

    NASA Technical Reports Server (NTRS)

    Vincente, R. O.

    1978-01-01

    The importance of the Earth's tides on Earth coordinates were examined for the following reasons: (1) the precision for obtaining the Earth's coordinates shows that the effects of Earth tides appear on the values obtained for the coordinates; (2) the possibility of determining the values of the Earth tides; and (3) the consideration of theoretical models that can compute the values of Earth tides. The astronomical and geodetic coordinates of a point at the Earth's surface are described.

  3. Effect of Irregularities in the Earth's Rotation on Relativistic Shifts in Frequency and Time of Earthbound Atomic Clocks

    NASA Astrophysics Data System (ADS)

    Fateev, V. F.; Kopeikin, S. M.; Pasynok, S. L., S. L.

    2015-10-01

    The effect of irregularities in the earth's rotation (precession and nutation of the earth's axis of rotation, oscillations in the modulus of the angular velocity, periodic deviations in the line of the poles, and the angular momentum of the globe) on the frequency and time of high-stability atomic clocks are examined in terms of the theory of relativity. It is shown that the relative shift in frequency and time owing to these effects can exceed 5×10-16.

  4. Loss of Water in Early Earth's Atmosphere and Its Effects on Habitability

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Glocer, Alex; Khazanov, George

    2015-08-01

    The short wavelength emission from the Sun has a profound impact on the Earth’s atmosphere. High energy photons ionize the atmosphere and produce photoelectrons. This process provides a major contribution to the acceleration of atmospheric ions due to the vertical separation of ions and electrons, and the formation of the resulting ambipolar electric field. Observations and theory suggest that even a relatively small fraction of super-thermal electrons (photoelectrons) produced due to photoionization can drive the ”polar wind” that is responsible for the transport of ionospheric constituents to the Earth’s magnetosphere.The young Sun was a magnetically active star generating powerful radiative output from its chromosphere, transition region and corona which was a few hundred times greater than that observed today. What effects would the photoionization processes due to the X-ray-UV solar flux from early Sun have on the loss of water from the early Earth?We use the Fokker-Plank code coupled with 1D hydrodynamic code to model the effect of intensive short-wavelength (X-rays to UV band) emission from the young Sun (3.8 and 4.4 Ga) on Earth's atmosphere. Our simulations include the photoionization processes of the Earth’s atmosphere forming a population of photoelectrons (E<600 eV), the kinetic effects of their propagation associated and their contribution in ionosphere - magnetosphere energy redistribution. Our coupled simulations show that the ambipolar electric field can drag atmospheric ions of oxygen and hydrogen to the magnetosphere and produce significant mass loss that can affect the loss of water from the early Earth in the first half a billion years. This process became less efficient in the next 0.2-0.3 Ga that could have provided a window of opportunity for origin of life.

  5. Effects of the observed J2 variations on the Earth's precession and nutation

    NASA Astrophysics Data System (ADS)

    Ferrándiz, José M.; Baenas, Tomás; Belda, Santiago

    2016-04-01

    The Earth's oblateness parameter J2 is closely related to the dynamical ellipticity H, which factorizes the main components of the precession and the different nutation terms. In most theoretical approaches to the Earth's rotation, with IAU2000 nutation theory among them, H is assumed to be constant. The precession model IAU2006 supposes H to have a conventional linear variation, based on the J2 time series derived mainly from satellite laser ranging (SLR) data for decades, which gives rise to an additional quadratic term of the precession in longitude and some corrections of the nutation terms. The time evolution of J2 is, however, too complex to be well approximated by a simple linear model. The effect of more general models including periodic terms and closer to the observed time series, although still unable to reproduce a significant part of the signal, has been seldom investigated. In this work we address the problem of deriving the effect of the observed J2 variations without resorting to such simplified models. The Hamiltonian approach to the Earth rotation is extended to allow the McCullagh's term of the potential to depend on a time-varying oblateness. An analytical solution is derived by means of a suitable perturbation method in the case of the time series provided by the Center for Space Research (CSR) of the University of Texas, which results in non-negligible contributions to the precession-nutation angles. The presentation focuses on the main effects on the longitude of the equator; a noticeable non-linear trend is superimposed to the linear main precession term, along with some periodic and decadal variations.

  6. Unusual locations of Earth's bow shock on September 24 - 25, 1987: Mach number effects

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.; Fairfield, Donald H.; Anderson, Oger R.; Carlton, Victoria E. H.; Paularena, Karolen I.; Lazarus, Alan J.

    1995-01-01

    International Sun Earth Explorer 1 (ISEE 1) and Interplanetary Monitoring Platform 8 (IMP 8) data are used to identify 19 crossings of Earth's bow shock during a 30-hour period following 0000 UT on September 24, 1987. Apparent standoff distances for the shock are calculated for each crossing using two methods and the spacecraft location; one method assumes the average shock shape, while the other assumes a ram pressure-dependent shock shape. The shock's apparent standoff distance, normally approximately 14 R(sub E), is shown to increase from near 10 R(sub E) initially to near 19 R(sub E) during an 8-hour period, followed by an excursion to near 35 R(sub E) (where two IMP 8 shock crossings occur) and an eventual return to values smaller than 19 R(sub E). The Alfven M(sub A) and fast magnetosonic M(sub ms). Mach numbers remain above 2 and the number density above 4/cu cm for almost the entire period. Ram pressure effects produce the initial near-Earth shock location, whereas expansions and contractions of the bow shock due to low Mach number effects account, qualitatively and semiquantitatively, for the timing and existence of almost all the remaining ISEE crossings and both IMP 8 crossings. Significant quantitative differences exist between the apparent standoff distances for the shock crossings and those predicted using the observed plasma parameters and the standard model based on Spreiter et al.'s (1966) gasdynamic equation. These differences can be explained in terms of either a different dependence of the standoff distance on Mach number at low M(sub A) and M(sub ms), or variations in shock shape with M(sub A) and M(sub ms) (becoming increasingly "puffed up" with decreasing M(sub A) and M(sub ms), as expected theoretically), or by a combination of both effects.

  7. Effect of a uniform sea-level change on the earth's rotation and gravitational field

    NASA Technical Reports Server (NTRS)

    Chao, B. Fong; O'Connor, William P.

    1988-01-01

    Global water redistriburtion between the oceans, atmosphere and continents causes changes in the earth's rotation and gravitational field. To conserve water mass, the effect of the small uniform change in sea-level must be considered. Explicit formulas are provided for these sea-level corrections to the gravitational Stokes coefficients, polar motion and length of day. In two recent publications, this sea-level correction term for polar motion was given incorrectly. These errors which arose from normalization conventions with the ocean function are corrected.

  8. Effects of clouds on the Earth radiation budget; Seasonal and inter-annual patterns

    NASA Technical Reports Server (NTRS)

    Dhuria, Harbans L.

    1992-01-01

    Seasonal and regional variations of clouds and their effects on the climatological parameters were studied. The climatological parameters surface temperature, solar insulation, short-wave absorbed, long wave emitted, and net radiation were considered. The data of climatological parameters consisted of about 20 parameters of Earth radiation budget and clouds of 2070 target areas which covered the globe. It consisted of daily and monthly averages of each parameter for each target area for the period, Jun. 1979 - May 1980. Cloud forcing and black body temperature at the top of the atmosphere were calculated. Interactions of clouds, cloud forcing, black body temperature, and the climatological parameters were investigated and analyzed.

  9. Cost-effective technology advancement directions for electric propulsion transportation systems in earth-orbital missions

    NASA Technical Reports Server (NTRS)

    Regetz, J. D., Jr.; Terwilliger, C. H.

    1979-01-01

    The directions that electric propulsion technology should take to meet the primary propulsion requirements for earth-orbital missions in the most cost effective manner are determined. The mission set requirements, state of the art electric propulsion technology and the baseline system characterized by it, adequacy of the baseline system to meet the mission set requirements, cost optimum electric propulsion system characteristics for the mission set, and sensitivities of mission costs and design points to system level electric propulsion parameters are discussed. The impact on overall costs than specific masses or costs of propulsion and power systems is evaluated.

  10. Effective and responsible teaching of climate change in Earth Science-related disciplines

    NASA Astrophysics Data System (ADS)

    Robinson, Z. P.; Greenhough, B. J.

    2009-04-01

    topic to cover within the Earth Science-related curricula due to wide-ranging, and sometimes polarised, existing attitudes of students and levels of existing partial and sometimes flawed knowledge in addition to the troublesome concepts that need to be grasped. These issues highlight the responsibility and challenge inherent in teaching the subject of climate change and the importance of consideration of integrating sustainability issues with the core science of climate change. The talk will include a discussion of strategies and resources for the effective teaching of climate change topics for a range of levels and discipline backgrounds.

  11. The Pale Orange Dot: Spectral Effects of a Hazy Early Earth

    NASA Astrophysics Data System (ADS)

    Arney, G.; Domagal-Goldman, S.; Meadows, V.

    2014-03-01

    Several studies have suggested that the Archean Earth atmosphere had a photochemically generated hydrocarbon haze similar to that of Titan, with important climactic implications for our early planet (Pavlov et al. 2001, Trainer al al. 2006, Haqq-Misra et al. 2008, Domagal-Goldman et al. 2008, Wolf and Toon 2012, Zerkle et al. 2012). Haze forms when the ratio of CH4 to CO2 in the atmosphere reaches ~0.1 (Haqq-Misra et al. 2008), and the resultant hydrocarbon haze can contain fractal particles. Compared to spherical particles, fractal particles produce less antigreenhouse cooling and can act as a UV shield (Wolf and Toon 2012), potentially enhancing the habitability of our young planet. If hazy exoplanets are common, the effects of hazes on planetary spectra will be relevant to future exoplanet spectral characterization missions. Previous studies of the detectability of biosignatures on early Earth (e.g. Kaltenegger et al. 2007) have not incorporated the effect of hazes. We consider the implications of spherical and fractal organic aerosol hazes on the spectrum of Archean Earth, examining in particular the impact of a haze layer in discerning spectral features from H2O, CH4, and other gases that have been suggested as putative biosignatures on anoxic planets such as C2H6 (Domagal-Goldman et al. 2011). We use a modified version of the 1-D photochemical code developed originally by Kasting et al. (1979) to generate a self-consistent haze in the model Archean atmosphere. The 1-D line-by-line fully multiple scattering Spectral Mapping Atmospheric Radiative Transfer Model (SMART) (Meadows and Crisp 1996) is then used to generate synthetic spectra of early Earth with haze. In the thermal IR, haze decreases the effective emitting temperature, so the planet appears colder than its surface temperature would dictate. Haze scattering significantly depletes the radiation at short wavelengths, but at longer visible wavelengths the haze increases the reflectivity making the planet

  12. Metal enhanced fluorescence in rare earth doped plasmonic core-shell nanoparticles.

    PubMed

    Derom, S; Berthelot, A; Pillonnet, A; Benamara, O; Jurdyc, A M; Girard, C; Colas des Francs, G

    2013-12-13

    We theoretically and numerically investigate metal enhanced fluorescence of plasmonic core-shell nanoparticles doped with rare earth (RE) ions. Particle shape and size are engineered to maximize the average enhancement factor (AEF) of the overall doped shell. We show that the highest enhancement (11 in the visible and 7 in the near-infrared) is achieved by tuning either the dipolar or the quadrupolar particle resonance to the rare earth ion's excitation wavelength. Additionally, the calculated AEFs are compared to experimental data reported in the literature, obtained in similar conditions (plasmon mediated enhancement) or when a metal-RE energy transfer mechanism is involved.

  13. Propagation effects on radio range and noise in earth-space telecommunications

    NASA Technical Reports Server (NTRS)

    Flock, W. L.; Slobin, S. D.; Smith, E. K.

    1982-01-01

    Attention is given to the propagation effects on radio range and noise in earth-space telecommunications. The use of higher frequencies minimizes ionospheric effects on propagation, but tropospheric effects often increase or dominate. For paths of geostationary satellites, and beyond, the excess range delay caused by the ionosphere and plasmasphere is proportional to the total electron content along the path and inversely proportional to frequency squared. The delay due to dry air is usually of the order of a few meters while the delay due to water vapor (a few tens of centimeters) is responsible for most of the temporal variation in the range delay for clean air. For systems such as that of the Voyager spacecraft, and for attenuation values up to about 10 dB, increased sky noise degrades the received signal-to-noise ratio more than does the reduction in signal level due to attenuation.

  14. On the effect of ocean tides and tesseral harmonics on spacecraft flybys of the Earth

    NASA Astrophysics Data System (ADS)

    Acedo, L.

    2016-12-01

    The so-called flyby anomaly has encouraged several authors to analyse in detail the minor perturbative contributions to the trajectory of spacecraft performing a flyby manoeuvre. This anomaly consist of an unexplained increase or decrease of the asymptotic velocity of the spacecraft after a flyby of the Earth in the range of a few mm per second. Some order of magnitude estimations have been performed in recent years to dismiss many possible conventional effects as the source of such an anomaly but no explanation has been found yet. In this paper we perform a study of the perturbation induced by ocean tides in a flybying spacecraft by considering the time dependence of the location of the high tide as the Moon follows its orbit. We show that this effect implies a change of the spacecraft velocity of a few micrometres per second. We also consider the coupling of tesseral harmonics inhomogeneities and the rotation of the Earth and its impact on the spacecraft outgoing velocity. Significant corrections to the observed asymptotic velocities are found in this case but neither their sign nor their magnitude coincide with the anomalies. So, we can also rule this out as a conventional explanation.

  15. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    NASA Technical Reports Server (NTRS)

    Luehr, Hermann; Xiong, Chao; Olsen, Nils; Le, Guan

    2016-01-01

    Magnetospheric currents play an important role in the electrodynamics of near- Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field. Significant progress in interpreting the magnetic fields from the different sources has been achieved thanks to magnetic satellite missions like Ørsted, CHAMP and now Swarm. Of particular interest for this article is a proper representation of the magnetospheric ring current effect. Uncertainties in modelling its effect still produce the largest residuals between observations and present-day geomagnetic field models. A lot of progress has been achieved so far, but there are still open issues like the characteristics of the partial ring current. Other currents discussed are those flowing in the magnetospheric tail. Also their magnetic contribution at LEO orbits is non-negligible. Treating them as an independent source is a more recent development, which has cured some of the problems in geomagnetic field modelling. Unfortunately there is no index available for characterizing the tail current intensity. Here we propose an approach that may help to properly quantify the magnetic contribution from the tail current for geomagnetic field modelling. Some open questions that require further investigation are mentioned at the end.

  16. Uptake and effect of rare earth elements on gene expression in Methylosinus trichosporium OB3b

    DOE PAGES

    Gu, Wenyu; Farhan Ul Haque, Muhammad; DiSpirito, Alan A.; ...

    2016-05-12

    It is well-known that M. trichosporium OB3b has two forms of methane monooxygenase responsible for the initial conversion of methane to methanol, a cytoplasmic (soluble) methane monooxygenase (sMMO) and a membrane-associated (particulate) methane monooxygenase (pMMO) and that copper strongly regulates expression of these alternative forms of MMO. More recently, it has been discovered that M. trichosporium OB3b has multiple types of the methanol dehydrogenase (MeDH), i.e. the Mxa-MeDH and Xox-MeDH, and the expression of these two forms is regulated by the availability of the rare earth element, cerium. Here we extend these studies and show that lanthanum, praseodymium, neodymium andmore » samarium also regulate expression of alternative forms of MeDH. The effect of these rare earth elements on MeDH expression, however, was only observed in the absence of copper. Further, a mutant of M. trichosporium OB3b where the Mxa-MeDH was knocked out was able to grow in the presence of lanthanum, praseodymium and neodymium, but was not able to grow in the presence of samarium. In conclusion, collectively these data suggest that multiple levels of gene regulation by metals exist in M. trichosporium OB3b but that copper overrides the effect of other metals by an as yet unknown mechanism.« less

  17. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Xiong, Chao; Olsen, Nils; Le, Guan

    2017-03-01

    Magnetospheric currents play an important role in the electrodynamics of near-Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field. Significant progress in interpreting the magnetic fields from the different sources has been achieved thanks to magnetic satellite missions like Ørsted, CHAMP and now Swarm. Of particular interest for this article is a proper representation of the magnetospheric ring current effect. Uncertainties in modelling its effect still produce the largest residuals between observations and present-day geomagnetic field models. A lot of progress has been achieved so far, but there are still open issues like the characteristics of the partial ring current. Other currents discussed are those flowing in the magnetospheric tail. Also their magnetic contribution at LEO orbits is non-negligible. Treating them as an independent source is a more recent development, which has cured some of the problems in geomagnetic field modelling. Unfortunately there is no index available for characterising the tail current intensity. Here we propose an approach that may help to properly quantify the magnetic contribution from the tail current for geomagnetic field modelling. Some open questions that require further investigation are mentioned at the end.

  18. Effects of rare-earth filters on patient exposure and image contrast

    SciTech Connect

    Mauriello, S.M.; Washburn, D.B.; Matteson, S.R.

    1987-08-01

    Minimizing patient exposure while maintaining a diagnostically acceptable radiograph is a major goal in diagnostic radiography. Rare-earth filters may be the means to achieve this goal due to their band-pass effect. The purpose of this study was to examine the image contrast effects and exposure reductions for various thicknesses of aluminum, samarium, gadolinium, gadolinium oxysulfide, and gadolinium oxysulfide added to 2.5 mm of aluminum. Trials were conducted on an intra-oral dental x-ray unit (range, 65 to 90 kVp). When compared with conventional aluminum, all of the rare-earth filters provided lower radiation exposures, with gadolinium in the metallic or oxysulfide form providing the lowest exposures. Samarium, at a thickness of 0.127 mm, yielded the highest image contrast. Gadolinium or gadolinium oxysulfide added to 2.5 mm of aluminum resulted in a slight loss of contrast when compared with conventional aluminum filtration. This loss may not be clinically significant, and when coupled with the reduced exposure afforded by these filters, they become viable as acceptable alternatives to aluminum filtration.

  19. Effective Integration of the World-Wide Web in Earth Science Education.

    ERIC Educational Resources Information Center

    Herbert, Bruce; Bednarz, Sarah; Boyd, Tom; Blake, Sally; Harder, Vicki; Sutter, Marilyn

    The earth sciences is an evolving set of disciplines encompassing more than 30 specialties; however, earth scientists continue to be trained within the traditional disciplinary structure. Earth science education should focus not only on student acquisition and retention of factual knowledge, but also on the development of higher-order skills…

  20. The effect of the Earth's oblateness on the Moon's physical libration in latitude

    NASA Astrophysics Data System (ADS)

    Kondratyev, B. P.

    2013-05-01

    The Moon's physical libration in latitude generated by gravitational forces caused by the Earth's oblateness has been examined by a vector analytical method. Libration oscillations are described by a close set of five linear inhomogeneous differential equations, the dispersion equation has five roots, one of which is zero. A complete solution is obtained. It is revealed that the Earth's oblateness: a) has little effect on the instantaneous axis of Moon's rotation, but causes an oscillatory rotation of the body of the Moon with an amplitude of 0.072″ and pulsation period of 16.88 Julian years; b) causes small nutations of poles of the orbit and of the ecliptic along tight spirals, which occupy a disk with a cut in a center and with radius of 0.072″. Perturbations caused by the spherical Earth generate: a) physical librations in latitude with an amplitude of 34.275″; b) nutational motion for centers of small spiral nutations of orbit (ecliptic) pole over ellipses with semi-major axes of 113.850″ (85.158″) and the first pole rotates round the second one along a circle with radius of 28.691″; c) nutation of the Moon's celestial pole over an ellipse with a semi-major axis of 45.04″ and with an axes ratio of about 0.004 with a period of T = 27.212 days. The principal ellipse's axis is directed tangentially with respect to the precession circumference, along which the celestial pole moves nonuniformly nearly in one dimension. In contrast to the accepted concept, the latitude does not change while the Moon's poles of rotation move. The dynamical reason for the inclination of the Moon's mean equator with respect to the ecliptic is oblateness of the body of the Moon.

  1. Proceedings of the NASA Workshop on Atomic Oxygen Effects. [low earth orbital environment

    NASA Technical Reports Server (NTRS)

    Brinza, David E. (Editor)

    1987-01-01

    A workshop was held to address the scientific issues concerning the effects of atomic oxygen on materials in the low Earth orbital (LEO) environment. The program included 18 invited speakers plus contributed posters covering topics such as LEO spaceflight experiments, interaction mechanisms, and atomic oxygen source development. Discussion sessions were also held to organize a test program to evaluate atomic oxygen exposure facilities. The key issues raised in the workshop were: (1) the need to develop a reliable predictive model of the effects of long-term exposure of materials to the LEO environment; (2) the ability of ground-based exposure facilities to provide useful data for development of durable materials; and (3) accurate determination of the composition of the LEO environment. These proceedings include the invited papers, the abstracts for the contributed posters, and an account of the test program discussion sessions.

  2. On the diamagnetic effect of the plasma sheet near 60 earth radii.

    NASA Technical Reports Server (NTRS)

    Meng, C.-I.; Mihalov, J. D.

    1972-01-01

    The two-dimensional (YZ plane) spatial distribution of magnetic field magnitudes in the geomagnetic tail at the lunar distance is given in both the solar magnetospheric and the neutral-sheet coordinate systems by using three years of data from the Ames magnetometer on Explorer 35. The effect of changes in geomagnetic activity is also presented. In the magnetotail near 60 earth radii, a broad region in which the magnetic field intensity is relatively weak in comparison with that in the other region of the tail is located adjacent to the solar magnetospheric equatorial plane and the calculated neutral sheet. This depression of the field due to the diamagnetic effect of the plasma sheet is more evident during times of minimum geomagnetic activity.-

  3. Low Earth orbital atomic oxygen and ultraviolet radiation effects on polymers

    SciTech Connect

    Dever, J.A.

    1991-02-01

    Because atomic oxygen and solar ultraviolet radiation present in the low earth orbital (LEO) environment can alter the chemistry of polymers resulting in degradation, their effects and mechanisms of degradation must be determined in order to determine the long term durability of polymeric surfaces to be exposed on missions such as Space Station Freedom. The effects of atomic oxygen on polymers which contain protective coatings must also be explored, since unique damage mechanisms can occur in areas where the protective coatings has failed. Mechanisms can be determined by utilizing results from previous LEO missions, by performing ground based LEO simulation tests and analysis, and by carrying out focussed space experiments. A survey is presented of the interactions and possible damage mechanisms for environmental atomic oxygen and UV radiation exposure of polymers commonly used in LEO.

  4. Low Earth orbital atomic oxygen and ultraviolet radiation effects on polymers

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.

    1991-01-01

    Because atomic oxygen and solar ultraviolet radiation present in the low earth orbital (LEO) environment can alter the chemistry of polymers resulting in degradation, their effects and mechanisms of degradation must be determined in order to determine the long term durability of polymeric surfaces to be exposed on missions such as Space Station Freedom. The effects of atomic oxygen on polymers which contain protective coatings must also be explored, since unique damage mechanisms can occur in areas where the protective coatings has failed. Mechanisms can be determined by utilizing results from previous LEO missions, by performing ground based LEO simulation tests and analysis, and by carrying out focussed space experiments. A survey is presented of the interactions and possible damage mechanisms for environmental atomic oxygen and UV radiation exposure of polymers commonly used in LEO.

  5. The Effect of Low Earth Orbit Atomic Oxygen Exposure on Phenylphosphine Oxide-Containing Polymers

    NASA Technical Reports Server (NTRS)

    Connell, John W.

    2000-01-01

    Thin films of phenylphosphine oxide-containing polymers were exposed to low Earth orbit aboard a space shuttle flight (STS-85) as part of flight experiment designated Evaluation of Space Environment and Effects on Materials (ESEM). This flight experiment was a cooperative effort between the NASA Langley Research Center (LaRC) and the National Space Development Agency of Japan (NASDA). The thin film samples described herein were part of an atomic oxygen exposure experiment (AOE) and were exposed to primarily atomic oxygen (1 X 1019 atoms/cm2). The thin film samples consisted of three phosphine oxide containing polymers (arylene ether, benzimidazole and imide). Based on post-flight analyses using atomic force microscopy, X-ray photoelectron spectroscopy, and weight loss data, it was found that atomic oxygen exposure of these materials efficiently produces a phosphate layer at the surface of the samples. This layer provides a barrier towards further attack by AO. Consequently, these materials do not exhibit linear erosion rates which is in contrast with most organic polymers. Qualitatively, the results obtained from these analyses compare favorably with those obtained from samples exposed to atomic oxygen and or oxygen plasma in ground based exposure experiments. The results of the low Earth orbit atomic oxygen exposure on these materials will be compared with those of ground based exposure to AO.

  6. North-South Asymmetries in Earth's Magnetic Field. Effects on High-Latitude Geospace

    NASA Astrophysics Data System (ADS)

    Laundal, K. M.; Cnossen, I.; Milan, S. E.; Haaland, S. E.; Coxon, J.; Pedatella, N. M.; Förster, M.; Reistad, J. P.

    2017-03-01

    The solar-wind magnetosphere interaction primarily occurs at altitudes where the dipole component of Earth's magnetic field is dominating. The disturbances that are created in this interaction propagate along magnetic field lines and interact with the ionosphere-thermosphere system. At ionospheric altitudes, the Earth's field deviates significantly from a dipole. North-South asymmetries in the magnetic field imply that the magnetosphere-ionosphere-thermosphere (M-I-T) coupling is different in the two hemispheres. In this paper we review the primary differences in the magnetic field at polar latitudes, and the consequences that these have for the M-I-T coupling. We focus on two interhemispheric differences which are thought to have the strongest effects: 1) A difference in the offset between magnetic and geographic poles in the Northern and Southern Hemispheres, and 2) differences in the magnetic field strength at magnetically conjugate regions. These asymmetries lead to differences in plasma convection, neutral winds, total electron content, ion outflow, ionospheric currents and auroral precipitation.

  7. Evidence of long term global decline in the Earth's thermospheric densities apparently related to anthropogenic effects

    NASA Astrophysics Data System (ADS)

    Keating, G. M.; Tolson, R. H.; Bradford, M. S.

    2000-05-01

    A study was performed of the long-term orbital decay of five Earth satellites with perigee altitudes averaging near 350km. To decouple long-term trend measurements from the effects of solar variability, measurements were evaluated during the years of solar minimum (1976, 1986 and 1996). Atmospheric densities derived from these essentially global measurements showed substantial evidence of a decline averaging 9.8 ± 2.5% in thermospheric density over 20 years pointing toward a long-term cooling of the upper atmosphere. Increases in greenhouse gases induced by human activity are hypothesized to warm the Earth's surface and lower atmosphere, but strongly cool the upper atmosphere. Assuming that the 10% increase in CO2 over these 20 years caused cooling resulting in the 10% decline in density, a doubling of CO2 could cause the thermospheric densities measured near 350km to decrease by a factor of 3. This decrease may shrink the altitude of a constant density surface by 40km before the end of the 21st century.

  8. Investigating the effect of lateral viscosity variations in the Earth's mantle

    NASA Astrophysics Data System (ADS)

    O'Farrell, K. A.; Lithgow-Bertelloni, C. R.

    2015-12-01

    Seismic tomography can be used to investigate radial viscosity variations on instantaneous flow models by predicting the global geoid and comparing with the observed geoid. This method is one of many that has been used to constrain viscosity structure in the Earth's mantle in the last few decades. Using the 3D mantle convection model, Stag-YY (e.g., Hernlund and Tackley, 2008), we are further able to explore the effect of lateral variations in viscosity in addition to the radial variations. Examining over 50 tomographic models we found notable differences by comparing a synthetically produced geoid with the observed geoid. Comparing S- and P-wave tomographic models, the S-wave models provided a better fit to the observed geoid. Using this large suite of 50 tomographic models, we have been able to constrain the radial viscosity structure of the Earth. We found that two types of viscosity profiles yielded equally good fits. A viscosity profile with a low transition zone viscosity and a lower mantle viscosity equal to the upper mantle, or a profile with a large lower mantle viscosity and a transition zone viscosity similar to the upper mantle. Using the set of radial viscosity profiles that gave the best fit to the observed geoid, we can explore a range of lateral viscosity variations and see how they affect the different types of tomographic models. Improving on previous studies of lateral viscosity variations (e.g. Ghosh, Becker and Zhong, 2010), we systematically explore a large range of tomographic models and density-velocity conversion factors. We explore which type of tomographic model (S- or P- wave) is more strongly affected by lateral viscosity variations, as well as the effect on isotropic and anisotropic models. We constrain the strength of lateral viscosity variations necessary to produce a high correlation between observed and predicted geoid anomalies. We will discuss the wavelength of flow that is most affected by the lateral viscosity variations

  9. Early Earth

    NASA Astrophysics Data System (ADS)

    Brown, M.

    2015-05-01

    Earth has continents, subduction and mobile lid plate tectonics, but details of the early evolution are poorly understood. Here I summarize the Hadean-Archean record, review evidence for a hotter Earth and consider geodynamic models for early Earth.

  10. Solar Irradiance Changes And Photobiological Effects At Earth's Surface Following Astrophysical Ionizing Radiation Events

    NASA Astrophysics Data System (ADS)

    Thomas, Brian; Neale, Patrick

    2016-01-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth for decades. Although there is some direct biological damage on the surface from redistributed radiation several studies have indicated that the greatest long term threat is from ozone depletion and subsequent heightened solar ultraviolet (UV) radiation. It is known that organisms exposed to this irradiation experience harmful effects such as sunburn and even direct damage to DNA, proteins, or other cellular structures. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In the present work, we employed a radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light). Using biological weighting functions we have considered a wide range of effects, including: erythema and skin cancer in humans; inhibition of photosynthesis in the diatom Phaeodactylum sp. and dinoflagellate Prorocentrum micans inhibition of carbon fixation in Antarctic phytoplankton; inhibition of growth of oat (Avena sativa L. cv. Otana) seedlings; and cataracts. We found that past work overestimated UVB irradiance, but that relative estimates for increase in exposure to DNA damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in

  11. Effective dose measured with a life size human phantom in a low Earth orbit mission.

    PubMed

    Yasuda, Hiroshi

    2009-03-01

    The biggest concern about the health risk to astronauts is how large the stochastic effects (cancers and hereditary effects) of space radiation could be. The practical goal is to determine the "effective dose" precisely, which is difficult for each crew because of the complex transport processes of energetic secondary particles. The author and his colleagues thus attempted to measure an effective dose in space using a life-size human phantom torso in the STS-91 Shuttle-Mir mission, which flew at nearly the same orbit as that of the International Space Station (ISS). The effective dose for about 10-days flight was 4.1 mSv, which is about 90% of the dose equivalent (H) at the skin; the lowest H values were seen in deep, radiation-sensitive organs/tissues such as the bone marrow and colon. Succeeding measurements and model calculations show that the organ dose equivalents and effective dose in the low Earth orbit mission are highly consistent, despite the different dosimetry methodologies used to determine them.

  12. Thermal inertia of near-Earth asteroids and magnitude of the Yarkovsky effect

    NASA Astrophysics Data System (ADS)

    Delbo, M.; Dell'Oro, A.; Harris, A. W.; Mottola, S.; Mueller, M.

    Thermal inertia of near-Earth asteroids and magnitude of the Yarkovsky effect M. Delbo* (1,2), A. Dell'Oro (2), A. W. Harris (3), S. Mottola (3), M. Mueller (3) (1) Observatoire de la Côte d'Azur B.P. 4229, 06034 Nice Cedex 4, France. (2) INAF-Osservatorio Astr. di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy. (3) DLR Institute of Planetary Research, Rutherfordstrasse 2, 12489 Berlin, Germany. Thermal inertia is the physical parameter that controls the temperature distribution over the surface of an asteroid. It affects the strength of the Yarkovsky effect, which causes orbital drift of km-sized asteroids and is invoked to explain the delivery of near-Earth asteroids (NEAs) from the main belt. Measurements of thermal inertia provide information on the presence or absence of loose surface material, such as thermally insulating regolith or dust. Such information is not only important for scientific studies of asteroid surface properties, but it is also vital for the design of lander missions and in the development of technology for the deflection of hazardous asteroids. At present, very little is known about the thermal inertia of asteroids in the km size range. Here we report on a method that has allowed us to derive a mean value for the thermal inertia of near-Earth asteroids on the basis of multi-wavelength thermal-infrared observations. We obtain a mean value of 200 ± 50 J m-2 s-0.5 K -1 corresponding to a surface thermal conductivity of 0.03 ± 0.01 W m-1 K-1 . We also identify a trend of increasing thermal inertia with decreasing asteroid size. As a consequence, the dependence of the Yarkovsky-induced semimajor axis drift rate on object diameter, D, departs from the 1/D dependence commonly assumed in models of the dynamical evolution of asteroids. *The work of Marco Delbo has been partially supported by the European Space Agency (ESA).

  13. Effects of low Earth orbit environment on the Long Duration Exposure Facility thermal control coatings

    NASA Technical Reports Server (NTRS)

    Sampair, Thomas R.; Berrios, William M.

    1992-01-01

    One of the benefits of the Long Duration Exposure Facility (LDEF) was the opportunity to study the before and after effects of low earth orbit space environment on the spacecraft thermal control coatings. Since the LDEF's thermal control was totally passive by design, the selection of the external surface absorptivity to emissivity ratio (alpha/epsilon) and the ability for the coating to retain the alpha/epsilon over time was an important consideration in the thermal design of the LDEF. The primary surface coating chosen for the LDEF structure was clear chromic anodized aluminum with an average design alpha/epsilon of 0.32/0.16. External surface absorptivity (alpha) and emissivity (epsilon) were measured on all intercostals, longerons, tray mounting flanges, thermal control panels, and a limited number of experiment surface coatings after the experiment trays were removed from the LDEF structure. All surface alpha/epsilon measurements were made using portable hand held infrared and solar spectrum reflectometers. The absorptivity measurements were taken with a Devices and Services SSR-ER version 5.0 solar spectra reflectometer which has a stated uncertainty of +/- 0.01, and all normal emissivity measurements were made using the Gier Dunkle DB-100 infrared reflectometer also with a stated uncertainty of +/- 0.01. Both instruments were calibrated in the laboratory by LaRC instrumentation personnel before being used in the field at KSC. A combined total of 733 measurements were taken on the anodized aluminum hardware which included the structure (intercostals, longerons, and center ring), earth and space end thermal control panels, and experiment tray mounting flanges. The facility thermal control coatings measured in this survey cover 33 percent of the total exposed LDEF surface area. To correlate low earth orbit environmental effects on the anodized coatings, measurements were taken in both exposed and unexposed surfaces and compared to quality assurance (QA

  14. Precise analytical description of the Earth matter effect on oscillations of low energy neutrinos

    SciTech Connect

    Ioannisian, A.N.; Kazarian, N.A.; Smirnov, A.Yu.; Wyler, D.

    2005-02-01

    We present a formalism for the matter effects in the Earth on low energy neutrino fluxes which is both accurate and has all the advantages of a full analytic treatment. The oscillation probabilities are calculated up to the second order term in {epsilon}(x){identical_to}2V(x)E/{delta}m{sup 2}, where V(x) is the neutrino potential at position x. We show the absence of large undamped phases which makes the expansion in {epsilon} well behaved. An improved expansion is presented in terms of the variation of V(x) around a suitable mean value which allows one to treat energies up to those relevant for supernova neutrinos. We discuss also the case of three-neutrino mixing.

  15. Compensation for effects of ambient temperature on rare-earth doped fiber optic thermometer

    NASA Technical Reports Server (NTRS)

    Adamovsky, G.; Sotomayor, J. L.; Krasowski, M. J.; Eustace, J. G.

    1989-01-01

    Variations in ambient temperature have a negative effect on the performance of any fiber optic sensing system. A change in ambient temperature may alter the design parameters of fiber optic cables, connectors, sources, detectors, and other fiber optic components and eventually the performance of the entire system. The thermal stability of components is especially important in a system which employs intensity modulated sensors. Several referencing schemes have been developed to account for the variable losses that occur within the system. However, none of these conventional compensating techniques can be used to stabilize the thermal drift of the light source in a system based on the spectral properties of the sensor material. The compensation for changes in ambient temperature becomes especially important in fiber optic thermometers doped with rare earths. Different approaches to solving this problem are searched and analyzed.

  16. Compensation for effects of ambient temperature on rare-earth doped fiber optic thermometer

    NASA Technical Reports Server (NTRS)

    Adamovsky, G.; Sotomayor, J. L.; Krasowski, M. J.; Eustace, J. G.

    1990-01-01

    Variations in ambient temperature have a negative effect on the performance of any fiber optic sensing system. A change in ambient temperature may alter the design parameters of fiber optic cables, connectors, sources, detectors, and other fiber optic components and eventually the performance of the entire system. The thermal stability of components is especially important in a system which employs intensity modulated sensors. Several referencing schemes have been developed to account for the variable losses that occur within the system. However, none of these conventional compensating techniques can be used to stabilize the thermal drift of the light source in a system based on the spectral properties of the sensor material. The compensation for changes in ambient temperature becomes especially important in fiber optic thermometers doped with rare earths. Different approaches to solving this problem are searched and analyzed.

  17. Sheath effects observed on a 10 meter high voltage panel in simulated low earth orbit plasma

    NASA Technical Reports Server (NTRS)

    Mccox, J. E.; Konradi, A.

    1979-01-01

    A large (1m x 10m) flat surface of conductive material was biased to high voltage (+ or - 3000 V) to simulate the behavior of a large solar array in low earth orbit. The model array was operated in a plasma environment of 1,000 to 1,000,000/cu cm, with sufficient free space around it for the resulting plasma sheaths to develop unimpeded for 5-10 meters into the surrounding plasma. Measurements of the resulting sheath thickness were obtained. The observed thickness varied approximately as V to the 3/4 power and N to the 1/2 power. This effect appears to limit total current leakage from the test array until sheath dimensions exceed about 1 meter. Total leakage current was also measured with the array.

  18. Relationship between microstructure and efficiency of lithium silicate scintillating glasses: The effect of alkaline earths

    SciTech Connect

    Bliss, M.; Craig, R.A.; Sunberg, D.S.; Weber, M.J.

    1996-12-31

    Lithium silicate glasses containing Ce{sup 3+} are known to be scintillators. Glasses in this family in which the Li is enriched ({sup 6}Li) are used as neutron detectors. The addition of Mg to this glass is known to increase the scintillation efficiency. We have found that substituting other alkaline earths results in a monotonic decrease of the scintillation efficiency with increasing atomic number. The total variation in scintillation efficiency from Mg to Ba is nearly a factor of 3. Prior experiments with this glass family show small differences in Raman and fluorescence spectra; evidence from thermoluminescence experiments indicates that the scintillation efficiency is most strongly correlated with structural effects in the neighborhood of the Ce{sup 3+} activator ion. The results of low-temperature studies of fluorescence and thermoluminescence of these glasses will be reported.

  19. Ammonia photolysis and the greenhouse effect in the primordial atmosphere of the earth

    NASA Technical Reports Server (NTRS)

    Kuhn, W. R.; Atreya, S. K.

    1979-01-01

    Photochemical calculations indicate that in the prebiotic atmosphere of earth ammonia would have been irreversibly converted to N2 in less than 40 years if the ammonia surface mixing ratio were no more than 0.0001. However, if a continuous outgassing of ammonia were maintained, radiative-equilibrium calculations indicate that a surface mixing ratio of ammonia of 0.0001 or greater would provide a sufficient greenhouse effect to keep the surface temperature above freezing. With a 0.0001 mixing ratio of ammonia, 60% to 70% of the present-day solar luminosity would be adequate to maintain surface temperatures above freezing. A lower limit to the time constant for accumulation of an amount of nitrogen equivalent to the present day value is 10 my if the outgassing were such as to provide a continuous surface mixing ratio of ammonia of at least 0.00001.

  20. Health effects and toxicity mechanisms of rare earth elements-Knowledge gaps and research prospects.

    PubMed

    Pagano, Giovanni; Guida, Marco; Tommasi, Franca; Oral, Rahime

    2015-05-01

    In the recent decades, rare earth elements (REE) have undergone a steady spread in several industrial and medical applications, and in agriculture. Relatively scarce information has been acquired to date on REE-associated biological effects, from studies of bioaccumulation and of bioassays on animal, plant and models; a few case reports have focused on human health effects following occupational REE exposures, in the present lack of epidemiological studies of occupationally exposed groups. The literature is mostly confined to reports on few REE, namely cerium and lanthanum, whereas substantial information gaps persist on the health effects of other REE. An established action mechanism in REE-associated health effects relates to modulating oxidative stress, analogous to the recognized redox mechanisms observed for other transition elements. Adverse outcomes of REE exposures include a number of endpoints, such as growth inhibition, cytogenetic effects, and organ-specific toxicity. An apparent controversy regarding REE-associated health effects relates to opposed data pointing to either favorable or adverse effects of REE exposures. Several studies have demonstrated that REE, like a number of other xenobiotics, follow hormetic concentration-related trends, implying stimulatory or protective effects at low levels, then adverse effects at higher concentrations. Another major role for REE-associated effects should be focused on pH-dependent REE speciation and hence toxicity. Few reports have demonstrated that environmental acidification enhances REE toxicity; these data may assume particular relevance in REE-polluted acidic soils and in REE mining areas characterized by concomitant REE and acid pollution. The likely environmental threats arising from REE exposures deserve a new line of research efforts.

  1. Effects of CubeSat Deployments in Low-Earth Orbit

    NASA Technical Reports Server (NTRS)

    Matney, M. J.; Vavrin, A. B.; Manis, A. P.

    2017-01-01

    Long-term models, such as NASA's LEGEND (LEO (Low-Earth Orbit)-to-GEO (Geosynchrous Earth Orbit) Environment Debris) model, are used to make predictions about how space activities will affect the long-term evolution of the debris environment. Part of this process is to predict how spacecraft and rocket bodies will be launched and left in the environment in the future. This has usually been accomplished by repeating past launch history to simulate future launches. It was partially upon the basis of the results of such models that both national and international orbital debris mitigation guidelines - especially the "25-year rule" for post-mission disposal - were determined. The proliferation of Cubesat launches in recent years, however, has raised concerns that we are seeing a fundamental shift in how humans launch satellites into space that may alter the assumptions upon which our current mitigation guidelines are based. The large number of Cubesats, and their short lifetime and general inability to perform collision avoidance, potentially makes them an important new source of debris. The NASA Orbital Debris Program Office (ODPO) has conducted a series of LEGEND computations to investigate the long-term effects of adding Cubesats to the environment. Several possible future scenarios were simulated to investigate the effects of the size of future Cubesat launches and the efficiency of post-mission disposal on the proliferation of catastrophic collisions over the next 200 years. These results are compared to a baseline "business-as-usual" scenario where launches are assumed to continue as in the past without major Cubesat deployments. Using these results, we make observations about the continued use of the 25-year rule and the importance of the universal application of post-mission disposal. We also discuss how the proliferation of Cubesats may affect satellite traffic at lower altitudes.

  2. Effects of sediment transport and deposition on crustal loading, Earth's gravitational field, and sea level

    NASA Astrophysics Data System (ADS)

    Ferrier, K.; Mitrovica, J. X.; Perron, T.; Milne, G. A.; Wickert, A. D.

    2012-12-01

    Spatial patterns in static sea level are controlled by the interplay between the history of ice mass variations and the associated deformational, gravitational and rotational perturbations in the Earth's state. Over the last decade, there has been a renewed effort to extend classic treatments of ice-age sea-level change (Farrell and Clark, 1976) to incorporate effects such as shoreline migration due to the local onlap or offlap of seawater and changes in the extent of grounded, marine-based ice, as well as feedbacks between sea level and the orientation of Earth's rotation axis. To date, the impact of sediment transport - whether in the context of glacial processes, or other processes such as fluvial deposition - has not been incorporated into a gravitationally self-consistent sea-level theory. Here we briefly summarize the main elements of a new sea-level theory that includes sediment transport, and we apply this new theory to investigate crustal deformation and sea-level changes driven by sediment deposition on the Mississippi fan in the Gulf of Mexico. The calculations incorporate sediment transport from the start of the last glacial cycle through to the present and are constrained to conserve sediment and ocean mass. We compare relative sea level histories predicted with and without sediment transport at sites in and around the Gulf of Mexico, and we quantify the relative impacts of gravitational and deformational effects of sediment deposition. We also explore the extent to which sea-level changes associated with sediment transport impact the interpretation of paleo-sea-level records. Our new sea-level formulation provides an important component of a comprehensive coupling between sediment transfer and sea level on local, regional and global spatial scales, and on time scales extending from decades to tens of thousands of years. References: Farrell, W.E., and Clark, J.A., 1976. On postglacial sea level: Geophysical Journal of the Royal Astronomical Society, v

  3. Effect of gravity on terminal particle settling velocity on Moon, Mars and Earth

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2013-04-01

    Gravity has a non-linear effect on the settling velocity of sediment particles in liquids and gases due to the interdependence of settling velocity, drag and friction. However, StokeśLaw, the common way of estimating the terminal velocity of a particle moving in a gas of liquid assumes a linear relationship between terminal velocity and gravity. For terrestrial applications, this "error" is not relevant, but it may strongly influence the terminal velocity achieved by settling particles on Mars. False estimates of these settling velocities will, in turn, affect the interpretation of particle sizes observed in sedimentary rocks on Mars. Wrong interpretations may occur, for example, when the texture of sedimentary rocks is linked to the amount and hydraulics of runoff and thus ultimately the environmental conditions on Mars at the time of their formation. A good understanding of particle behaviour in liquids on Mars is therefore essential. In principle, the effect of lower gravity on settling velocity can also be achieved by reducing the difference in density between particle and gas or liquid. However, the use of such analogues simulating the lower gravity on Mars on Earth is creates other problems because the properties (i.e. viscosity) and interaction of the liquids and sediment (i.e. flow around the boundary layer between liquid and particle) differ from those of water and mineral particles. An alternative for measuring the actual settling velocities of particles under Martian gravity, on Earth, is offered by placing a settling tube on a reduced gravity flight and conduct settling tests within the 20 to 25 seconds of Martian gravity that can be simulated during such a flight. In this presentation we report the results of such a test conducted during a reduced gravity flight in November 2012. The results explore the strength of the non-linearity in the gravity-settling velocity relationship for terrestrial, lunar and Martian gravity.

  4. Solar irradiance changes and photobiological effects at earth's surface following astrophysical ionizing radiation events.

    PubMed

    Thomas, Brian C; Neale, Patrick J; Snyder, Brock R

    2015-03-01

    Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the Tropospheric Ultraviolet and Visible (TUV) radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance but that relative estimates for increase in exposure to DNA-damaging radiation are still similar to our improved calculations. We also found that the intensity of biologically damaging radiation varies widely with organism and specific impact considered; these results have implications for biosphere-level damage following astrophysical ionizing radiation events. When considering changes in surface-level visible light irradiance, we found that, contrary to previous assumptions, a decrease in irradiance is only present for a short time in very limited geographical areas; instead we found a net increase for most of the modeled time-space region. This result has implications for proposed climate changes associated with ionizing radiation events.

  5. Changes in the Earth's Spin Rotation due to the Atmospheric Effects and Reduction in Glaciers

    NASA Astrophysics Data System (ADS)

    Na, Sung-Ho; Cho, Jungho; Kim, Tu-Hwan; Seo, Kiweon; Youm, Kookhyoun; Yoo, Sung-Moon; Choi, Byungkyu; Yoon, Hasu

    2016-12-01

    The atmosphere strongly affects the Earth's spin rotation in wide range of timescale from daily to annual. Its dominant role in the seasonal perturbations of both the pole position and spinning rate of the Earth is once again confirmed by a comparison of two recent data sets; i) the Earth orientation parameter and ii) the global atmospheric state. The atmospheric semi-diurnal tide has been known to be a source of the Earth's spin acceleration, and its magnitude is re-estimated by using an enhanced formulation and an up-dated empirical atmospheric S2 tide model. During the last twenty years, an unusual eastward drift of the Earth's pole has been observed. The change in the Earth's inertia tensor due to glacier mass redistribution is directly assessed, and the recent eastward movement of the pole is ascribed to this change. Furthermore, the associated changes in the length of day and UT1 are estimated.

  6. The Effect of Teaching Strategies Using Models on Preservice Elementary Teachers' Conceptions about Earth-Sun-Moon Relationships.

    ERIC Educational Resources Information Center

    Callison, Priscilla L.; Wright, Emmett L.

    This study investigated the effect of three specific hands-on teaching strategies on the attainment and alteration of preservice elementary teachers' conceptions about earth-sun-moon relationships. The subjects (n=76) were enrolled in an elementary school science methods course. The descriptive nature of this study explored: (1) the effect of two…

  7. Semi analytical model for the effective grain size profile in the mantle of the Earth: partitioning between diffusion and dislocation creep through the Earth's history

    NASA Astrophysics Data System (ADS)

    Rozel, A. B.; Golabek, G.; Thielmann, M.; Tackley, P.

    2015-12-01

    We present a semi analytical model of mantle convection able to predict the grain size profile of the present day Earth. Grain size evolution has been studied with increasing interest over the last decades but its behavior in both mantle and lithosphere remains largely misunderstood due to its non-linearity. Several recent studies suggest that it might play a fundamental role in localization of deformation in the lithosphere but we focus here on the mantle in which we also observe important processes.We propose a 1D compressible thermal convection model based on the equality of advective heat flux and the integral of viscous dissipation in the whole domain. Imposing mass conservation, our model is able to predict all rheological parameters able to produce both present day average surface velocity and lower mantle viscosity. Composite rheologies involving dislocation creep and grain size dependent diffusion creep are considered. The effect of phase transitions on the grain size is also explicitely taken into account. We present the family of solutions for the activation volume and the viscosity jump at the 660 discontinuity according to any initial choice of activation energy. The scaling laws for rheological parameters obtained are compared to self-consistent evolutionary simulations of mantle convection in 2D spherical annulus geometry considering composite rheologies. The transition between diffusion and dislocation creep due to the cooling of the Earth is illustrated in a set of numerical simulations starting from the physical conditions of the Archean.

  8. The Effects of Solar Variability on Earth's Climate: A Workshop Report

    NASA Technical Reports Server (NTRS)

    2012-01-01

    varbility and Earth s climate is multifaceted and that some components are understood better than others. According to two presenters on paleoclimate, there is a need to study the idiosyncrasies of each key proxy record. Yet they also emphasized that there may be an emerging pattern of paleoclimate change coincident with periods of solar activity and inactivity, but only on long timescales of multiple decades to millennia. Several speakers discussed the effects of particle events and cosmic-ray variability. These are all areas of exciting fundamental research; however, they have not yet led to conclusive evidence for significant related climate effects. The key problem of attribution of climate variability on the timescales of the Little Ice Age and the Maunder Minimum were directly addressed in several presentations. Several workshop participants remarked that the combination of solar, paleoclimatic, and climate modeling research has the potential to dramatically improve the credibility of these attribution studies.

  9. Ground shock from multiple earth penetrator bursts: Effects for hexagonal weapon arrays

    SciTech Connect

    Kmetyk, L.N.; Yarrington, P.

    1990-08-01

    Calculations have been performed with the HULL hydrocode to study ground shock effects for multiple earth penetrator weapon (EPW) bursts in hexagonal-close-packed (HCP) arrays. Several different calculational approaches were used to treat this problem. The first simulations involved two-dimensional (2D) calculations, where the hexagonal cross-section of a unit-cell in an effectively-infinite HCP array was approximated by an inscribed cylinder. Those calculations showed substantial ground shock enhancement below the center of the array. To refine the analysis, 3D unit-cell calculations were done where the actual hexagonal cross-section of the HCP array was modelled. Results of those calculations also suggested that the multiburst array would enhance ground shock effects over those for a single burst of comparable yield. Finally, 3D calculations were run in which an HCP array of seven bursts was modelled explicitly. In addition, the effects of non-simultaneity were investigated. Results of the seven-burst HCP array calculations were consistent with the unit-cell results and, in addition, provided information on the 3D lethal contour produced by such an array.

  10. Carbon sequestration potential and climatic effects of reforestation in an Earth system model

    NASA Astrophysics Data System (ADS)

    Sonntag, Sebastian; Pongratz, Julia; Reick, Christian; Schmidt, Hauke

    2015-04-01

    Studies on the global climatic effects of afforestation have mainly focused on the carbon sequestration potential of plausible scenarios while neglecting biogeophysical effects or were based on highly idealised afforestation scenarios. Here we assess the reduction potential for the atmospheric CO2 concentration and possible consequences for the global climate of following a strong reforestation scenario during this century taking into account both biogeochemical and biogeophysical effects. We perform simulations using the Max Planck Institute for Meteorology Earth System Model (MPI-ESM), forced by anthropogenic emissions according to the Representative Concentration Pathway (RCP) 8.5, but using land use transitions according to RCP 4.5. Thereby we are able to isolate the effects of land use changes in this scenario in which agricultural intensification leads to abandonment of agricultural areas and a regrowth of forest of about 8 million km2 in our model. We find that this reforestation reduces the atmospheric CO2 concentration by about 85 ppm by the end of the century as compared to RCP 8.5. This value is higher than previous estimates for plausible reforestation scenarios, mostly because the CO2 fertilisation effect on the terrestrial vegetation has not been accounted for in previous studies. Due to the lower CO2 concentration the global mean temperature increase is reduced by about 0.27 K. Regionally the simulated effect may exceed 2 K, but the largest annual mean cooling signal occurs in only sparsely populated regions. Concerning temperature extremes, however, the effect can also be large in densely populated areas, mostly caused by local biogeophysical effects of the vegetation changes. Thus, we conclude that the mitigation potential of reforestation is higher than previously thought, the need for adaptation in many regions of the world is still strong, but temperature extremes may be reduced.

  11. Preliminary evaluation of effects of best management practices in the Black Earth Creek, Wisconsin, priority watershed

    USGS Publications Warehouse

    Walker, J.F.; Graczyk, D.J.; Olem, H.

    1993-01-01

    Nonpoint-source contamination accounts for a substantial part of the water quality problems in many watersheds. The Wisconsin Nonpoint Source Water Pollution Abatement Program provides matching money for voluntary implementation of various best management practices (BMPs). The effectiveness of BMPs on a drainage-basin scale has not been adequately assessed in Wisconsin by use of data collected before and after BMP implementation. The U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, monitored water quality in the Black Earth Creek watershed in southern Wisconsin from October 1984 through September 1986 (pre-BMP conditions). BMP implementation began during the summer of 1989 and is planned to continue through 1993. Data collection resumed in fall 1989 and is intended to provide information during the transitional period of BMP implementation (1990-93) and 2 years of post-BMP conditions (1994-95). Preliminary results presented for two subbasins in toe Black Earth Creek watershed (Brewery and Garfoot Creeks) are based on data collected during pre-BMP conditions and the first 3 years of the transitional period. The analysis includes the use of regressions to control for natural variability in the data and, hence, enhance the ability to detect changes. Data collected to date (1992) indicate statistically significant differences in storm mass transport of suspended sediment and ammonia nitrogen at Brewery Creek. The central tendency of the regression residuals has decreased with the implementation of BMPs; hence, the improvement in water quality in the Brewery Creek watershed is likely a result of BMP implementation. Differences in storm mass transport at Garfoot Creek were not detected, primarily because of an insufficient number of storms in the transitional period. As practice implementation continues, the additional data will be used to determine the level of management which results in significant improvements in water

  12. External and internal magnetic-field effects on ferroelectricity in orthorhombic rare-earth manganites

    NASA Astrophysics Data System (ADS)

    Kuwahara, H.; Noda, K.; Akaki, M.

    2006-03-01

    We report the dielectric and magnetic properties of the perovskite (Eu,Y)MnO3 crystal without the presence of the 4f magnetic moments of the rare earth ions. The subject compound, (Eu,Y)MnO3, was controlled the average ionic radius of the A site so that it was the same as that of TbMnO3 in which the intriguing magnetoelectric effect has been recently discovered. The (Eu,Y)MnO3 crystal was found to have two distinct ferroelectric phases with polarization along the a (Pa, T<=23K) and c (Pc, 23K<=T<=25K) axes in the orthorhombic Pbnm setting in a zero magnetic field. In addition, we have demonstrated a magnetic-field-induced switching between these ferroelectric phases: Pa changed to Pc by the application of magnetic fields parallel to the a axis (Ha). In analogy to the case of Pc in TbMnO3, this result is possibly interpreted as follows. In the case of (Eu,Y)MnO3, Mn 3d spins rotate in the ab plane and Pa would emerge in a zero field. In the Ha, the field will force the spins to rotate in the bc plane, in which Pc would be stabilized. Magnetization measurements supported this interpretation: We confirmed the change of the spin rotation axis of the helix from the c axis to the a axis induced by application of the Ha because there is no 4f moments acting as an internal magnetic field and interacting with the 3d spins. Results obtained with other rare-earth manganites such as (Gd,Tb)MnO3 and (Eu,Ho)MnO3 will be presented.

  13. Tissue deposition and toxicological effects of commercially significant rare earth oxide nanomaterials: Material and physical properties.

    PubMed

    Das, Soumen; Reed McDonagh, Philip; Selvan Sakthivel, Tamil; Barkam, Swetha; Killion, Kelsey; Ortiz, Julian; Saraf, Shashank; Kumar, Amit; Gupta, Ankur; Zweit, Jamal; Seal, Sudipta

    2017-03-01

    Rare earth oxide (REO) materials are found naturally in earth's crust and at the nanoscale these REO nanoparticles exhibit unique thermal, electrical, and physicochemical properties. REO nanoparticles are widely used in different industrial sectors for ceramics, glass polishing, metallurgy, lasers, and magnets. Recently, some of these REO nanoparticles have been identified for their potential application in medicine, including therapy, imaging, and diagnostics. Concurrent research into the REO nanomaterials' toxicities has also raised concern for their environmental impacts. The correlation of REO nanoparticles mediated toxicity with their physiochemical properties can help to design nanoparticles with minimal effect on the environment and living organisms. In vitro assay revealed toxicity toward Human squamous epithelial cell line (CCL30) and Human umbilical vascular endothelial cells (HUVEC) at a concentration of 100 µM and higher. In vivo results showed, with the exception of CeO2 and Gd2 O3 , most of the naoparticles did not clear or had minimum clearance (10-20%) from the system. Elevated levels of alanine transferase were seen for animals given each different nanoparticle, however the increases were not significant for CeO2 and Dy2 O3 . Nephrotoxicity was only seen in case of Dy2 O3 and Gd2 O3 . Lastly, histological examination revealed presence of swollen hepatocytes which further confirms toxicity of the commercial REO nanomaterials. The in vivo toxicity is mainly due to excessive tissue deposition (70-90%) due to the commercial REO nanoparticles' poor physical properties (shape, stability, and extent of agglomeration). Therefore, optimization of nanoparticles physical properties is very important. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 904-917, 2017.

  14. Effect of hydrocarbon adsorption on the wettability of rare earth oxide ceramics

    SciTech Connect

    Preston, Daniel J.; Miljkovic, Nenad; Sack, Jean; Queeney, John; Wang, Evelyn N.; Enright, Ryan

    2014-07-07

    Vapor condensation is routinely used as an effective means of transferring heat, with dropwise condensation exhibiting a 5 − 7x heat transfer improvement compared to filmwise condensation. However, state-of-the-art techniques to promote dropwise condensation rely on functional hydrophobic coatings, which are often not robust and therefore undesirable for industrial implementation. Natural surface contamination due to hydrocarbon adsorption, particularly on noble metals, has been explored as an alternative approach to realize stable dropwise condensing surfaces. While noble metals are prohibitively expensive, the recent discovery of robust rare earth oxide (REO) hydrophobicity has generated interest for dropwise condensation applications due to material costs approaching 1% of gold; however, the underlying mechanism of REO hydrophobicity remains under debate. In this work, we show through careful experiments and modeling that REO hydrophobicity occurs due to the same hydrocarbon adsorption mechanism seen previously on noble metals. To investigate adsorption dynamics, we studied holmia and ceria REOs, along with control samples of gold and silica, via X-Ray photoelectron spectroscopy (XPS) and dynamic time-resolved contact angle measurements. The contact angle and surface carbon percent started at ≈0 on in-situ argon-plasma-cleaned samples and increased asymptotically over time after exposure to laboratory air, with the rare earth oxides displaying hydrophobic (>90°) advancing contact angle behavior at long times (>4 days). The results indicate that REOs are in fact hydrophilic when clean and become hydrophobic due to hydrocarbon adsorption. Furthermore, this study provides insight into how REOs can be used to promote stable dropwise condensation, which is important for the development of enhanced phase change surfaces.

  15. K-20 educator collaboration effective at conveying EarthScope science to middle school teachers

    NASA Astrophysics Data System (ADS)

    Pratt-Sitaula, B.; Butler, R. F.; Whitman, J. M.; Granshaw, F. D.; Groom, R.; Hedeen, C.; Magura, B.; Thompson, D.; Johnson, J. A.

    2010-12-01

    Teachers on the Leading Edge (TOTLE) program has developed an innovative model for middle school teacher professional development workshops that has proven effective at improving teacher knowledge of Pacific Northwest plate margin hazards and EarthScope science as well as leading to high rates of subsequent curriculum implementation. The key elements which appear to have led to the successes are: 1) facilitation team with broad content and educator expertise from K-12 master teachers and community college instructors to university and research scientists; 2) regional team format which encourages development of learning communities to continue past the workshop end; and 3) extensive “kit” of teaching materials for easy transfer to the classroom. The 1-week workshops were conducted during the summers of 2008-2010 and included 35 Pacific Northwest middle school teachers and 5 community college (or similar) regional team leaders each year. Content sessions and field trips were conducted by geoscientists from universities and research institutions (USGS, IRIS, UNAVCO, etc.). Teaching implementation sessions were conducted by K-12 master Earth science teachers. Approximately 10% of workshop costs were devoted to teaching material “kits” for all participants. Teacher confidence on workshop content topics increased on a 4-point scale (1 = “not at all confident”; 4 = “very confident”) from 2.7 to 3.2 to 3.7 on pre, immediately-post, and 8-month follow up surveys, respectively. Teacher performance on a content test improved an average of 19% after the workshop. Greater than 75% of teachers implemented at least 6 of the curricular elements in the year following the workshop. More concrete linking of the most complex topics (Ex. Cascadia GPS) to simpler elements led to improved implementation of those difficult curricular topics between 2008 and 2009 (Ex. from 28% to 40% implementation).

  16. DataStreme Earth's Climate System: Building a Climate Literate Society through Effective Partnerships

    NASA Astrophysics Data System (ADS)

    Brey, J. A.; Geer, I. W.; Weinbeck, R. S.; Mills, E. W.; Nugnes, K. A.; Stimach, A. E.

    2015-12-01

    Effective partnerships are key to increasing climate and overall environmental literacy. Financial support from NSF, NASA, and NOAA has allowed the American Meteorological Society (AMS) to offer DataStreme courses for almost 20 years. DataStreme Atmosphere, Ocean, and Earth's Climate System (ECS) are offered each fall and spring semester by Local Implementation Teams (LITs) across the country in coordination with AMS Education Program scientists and educators who develop instructional materials, provide logistical support to the LITs, and administer the project. A long-standing partnership with State University of New York's The College at Brockport gives teachers the opportunity to receive 3 tuition-free graduate credits upon successful completion of each DataStreme course and construction of a Plan of Action for educational peer-training. DataStreme ECS investigates the fundamental science of Earth's climate system, explores humans' impact on it, and identifies actions needed in response to climate change. The course provides participants with the knowledge to make informed climate decisions. In fact, according to a recent three-year study conducted by AMS, 98% of DataStreme ECS participants reported an increase in environmental literacy as a result of the course. DataStreme Atmosphere, Ocean, and ECS content has been improved because of AMS partnerships with NOAA and NASA. Specifically, hundreds of NASA and NOAA scientists and faculty from numerous institutions both domestic and abroad have contributed and reviewed DataStreme ECS content. Additional collaborations with Consortium for Ocean Leadership and the U.S. Ice Drilling Program greatly improved the course's paleoclimate content. Looking ahead, the Climate Resilience Toolkit from NOAA's Climate Program Office will further bolster the course this fall. These partnerships have resulted in a powerful, content-rich climate science course for K-12 teachers, building the foundation to a climate literate society.

  17. Quantifying fractured crystalline-rock properties using well tests, earth tides and barometric effects

    NASA Astrophysics Data System (ADS)

    Burbey, Thomas J.; Hisz, David; Murdoch, Lawrence C.; Zhang, Meijing

    2012-01-01

    SummaryCharacterization of fractured rock aquifers often requires the acquisition and analysis of diverse datasets obtained from various instrumentation configurations. In this investigation at the fractured rock research site in Floyd County, Virginia, a high-precision borehole extensometer and tiltmeter were used during pumping to monitor deformation in the vicinity of fractures identified from borehole logging. Strain data obtained from earth tide analyses were used with the extensometer and tiltmeter data to quantify hydromechanical properties, including fracture volumetric specific storage, porosity, Poisson's ratio, the drained formation elastic modulus, and the effective dip direction of the fracture. Borehole tiltmeter data were used to estimate deformation caused by an aquifer test consisting of three pumping and recovery periods performed in well EX-1. During each period of the aquifer test the extensometer, located in W-03 and 27.7 m from the pumping well, was anchored over 2-m-long sections of (1) a fracture in hydraulic communication with EX-1, (2) a fracture that is not hydraulically connected with EX-1, and (3) an unfractured portion of bedrock directly above the hydraulically connected fracture. Results from the pumping tests yielded compressibilities of 1.3 × 10 -11 Pa -1, and 1.7 × 10 -11 Pa -1 for the lower and upper fractures, respectively. When coupled with areal strain calculated from earth tide analyses the volumetric specific storage values are 3.2 × 10 -11 Pa -1, and 2.8 × 10 -11 Pa -1 and the Poisson's ratios are 0.26 and 0.31, respectively. Using this with a calculated barometric efficiency of 0.45 allows for porosity calculations of 0.02 and 0.03, respectively for the vicinity of fractures in well W-03.

  18. Bidirectional Spectral Reflectance of Earth Resources: Influence of Scene Complexity and Atmospheric Effects on Remote Sensing

    NASA Technical Reports Server (NTRS)

    Diner, D. J.

    1984-01-01

    Practical methods for remote sensing when scene complexity and atmospheric effects modify intrinsic reflective properties are developed. The radiation history from ground to space of light reflected from individual leaves is initially multiply scattered within the crop canopy, whose geometry provides a controlling influence, then scattered and attenuated as a result of transmission through the Earth's atmosphere. The experimental and theoretical tools for studying these effects quantitatively are under development. A new radiative transfer code which uses Fourier transforms to solve the 3-D equation of transfer was developed. The initial version permits inhomogeneous non-Lambertian surfaces but assumes horizontal uniformity for the atmosphere. The computational results are in excellent agreement with Monte Carlo calculations. Laboratory apparatus to study the variation of spectral reflectance of individual leaves as a function of illumination incidence angle and reflection angle was used. These data can then be used in models to determine canopy scattering effects. Stress tests by observing leaf reflectance at 0.9 microns as a function of time following clipping from the stem was performed. A reflectance increase due to loss of water has been observed.

  19. Potential Effects of Heliogeophysical Activity on the Dynamics of Sudden Cardiac Death at Earth Middle Latitudes

    NASA Astrophysics Data System (ADS)

    Dimitrova, S.; Babayev, E.; Mustafa, F.

    2017-01-01

    Limited studies exist on comparing the possible effects of heliogeophysical activity (solar and geomagnetic) on the dynamics of sudden cardiac death (SCD) as a function of latitude on Earth. In this work we continue our earlier studies concerning the changing space environment and SCD dynamics at middle latitudes. The study covered 25 to 80-year old males and females, and used medical data provided by all emergency and first medical aid stations in the Grand Baku Area, Azerbaijan. Data coverage includedthe second peak of Solar Cycle 23 and its descending activity years followed by its long-lasting minimum. Gradation of geomagnetic activity into six levels was introduced to study the effect of space weather on SCD. The ANalysis Of VAriance (ANOVA) test was applied to study the significance of the geomagnetic activity effect, estimated by different geomagnetic indices, on SCD dynamics. Variations inthe number of SCDs occurring on days preceding and following the development of geomagnetic storms were also studied. Results revealed that the SCD number was largest on days of very low geomagnetic activity and on days proceeding and following geomagnetic storms with different intensities. Vulnerability for males was found to be higher around days of major and severe geomagnetic storms. Females, on the other hand, were more threatened around days of lower intensity storms. It is concluded that heliogeophysical activity could be considered as one of the regulating external/environmental factors in human homeostasis.

  20. The effects of geomagnetic disturbances on electrical systems at the earth's surface

    NASA Astrophysics Data System (ADS)

    Boteler, D. H.; Pirjola, R. J.; Nevanlinna, H.

    Geomagnetic disturbances have affected electrical systems on the ground for over 150 years. The first effects were noted on the early telegraph in the 1840s and in this century magnetic storms have caused power system blackouts and phone system outages. Affected systems include all those that use electrical conductors: whether for transmission of power or signals or where the conducting properties are incidental to their use such as with pipelines and railway tracks. In power systems geomagnetically induced currents cause partial saturation of power transformers producing transformer heating and distortion of the ac waveform leading to misoperation of relays and other equipment. On pipelines, induced currents may contribute to corrosion but also present a problem with the electrical surveys of the pipe performed to monitor the corrosion prevention systems. Severity of these effects depends on disturbance size, proximity to the auroral zone, and the conductivity structure of the Earth. Also significant are system parameters such as the use of higher resistance coatings on pipelines and the linking of power systems into larger networks. In this paper we have attempted to catalogue all the published reports of geomagnetic effects on electrical systems and show their occurrence in the context of the solar cycle and geomagnetic activity variations for the years 1844 to 1996.

  1. The effect of clouds on the earth's solar and infrared radiation budgets

    NASA Technical Reports Server (NTRS)

    Herman, G. F.; Wu, M.-L. C.; Johnson, W. T.

    1980-01-01

    The effect of global cloudiness on the solar and infrared components of the earth's radiation balance is studied in general circulation model experiments. A wintertime simulation is conducted in which the cloud radiative transfer calculations use realistic cloud optical properties and are fully interactive with model-generated cloudiness. This simulation is compared to others in which the clouds are alternatively non-interactive with respect to the solar or thermal radiation calculations. Other cloud processes (formation, latent heat release, precipitation, vertical mixing) were accurately simulated in these experiments. It is concluded that on a global basis clouds increase the global radiation balance by 40 W/sq m by absorbing longwave radiation, but decrease it by 56 W/sq m by reflecting solar radiation to space. The net cloud effect is therefore a reduction of the radiation balance by 16 W/sq m, and is dominated by the cloud albedo effect. Changes in cloud frequency and distribution and in atmospheric and land temperatures are also reported for the control and for the non-interactive simulations. In general, removal of the clouds' infrared absorption cools the atmosphere and causes additional cloudiness to occur, while removal of the clouds' solar radiative properties warms the atmosphere and causes fewer clouds to form. It is suggested that layered clouds and convective clouds over water enter the climate system as positive feedback components, while convective clouds over land enter as negative components.

  2. Acaricidal effect of different diatomaceous earth formulations against Tyrophagus putrescentiae (Astigmata: Acaridae) on stored wheat.

    PubMed

    Iatrou, Styliani A; Kavallieratos, Nickolas G; Palyvos, Nickolas E; Buchelos, Constantin T; Tomanović, Snezana

    2010-02-01

    Laboratory bioassays were conducted to evaluate the effect of different diatomaceous earth (DE) formulations against adults and immature stages of the stored-product mite species Tyrophagus putrescentiae (Schrank). Five DE formulations were used in the tests: SilicoSec, PyriSec, Insecto, Protect-It, and DEA-P. The tests were conducted at 25 degrees C and 75% RH, on wheat, Triticum aestivum L., treated with DEs at two dose rates, 0.2 and 0.5 g/kg. The mortality of mite individuals was measured after 5 d of exposure, and after 30 d the treated wheat was checked for T. putrescentiae offspring. Significant differences were noted among the DEs tested. Application of the lowest dose rate (0.2 g/kg) provided mortality of both adults and immatures that exceeded 78%, whereas the respective data for 0.5 g/kg were almost in all cases 100%. The adults of T. putrescentiae were more tolerant to DEs than the immature stages. Generally, PyriSec was the most effective against adults. Progeny production was dramatically reduced with the increase of dose. The results of the present work indicate that T. putrescentiae can be effectively controlled by DEs on wheat, at dose rates as low as 0.2 g/kg.

  3. Effects of rare earth elements on the distribution of mineral elements and heavy metals in horseradish.

    PubMed

    Wang, Lihong; Huang, Xiaohua; Zhou, Qing

    2008-09-01

    In order to investigate the effects of rare earth elements (REEs) on horseradish, the distribution of the mineral elements and heavy metals in different organs of horseradish have been studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Meanwhile, three variable major parameters, namely the concentration of REEs, the type of REEs, and the growth stage of plant were chosen. The results indicated that the test REEs, Ce(III) and Tb(III), could be accumulated in leaves, stems and roots of horseradish. In addition, we found that the content of mineral elements was increased in horseradish treated with 20mgl(-1) of Ce(III), but not those with the 20mgl(-1) of Tb(III). Moreover, the content of mineral elements in horseradish was decreased with the increasing concentration of REEs (100, 300mgl(-1)). Furthermore, we found that there were the opposite effects on the content of the heavy metals in horseradish treated with REEs. Finally, we found that the effect of REEs on the accumulation of REEs, and the content of mineral elements or heavy metals of horseradish during vigorous growth stage, no matter positive or negative, was more obvious than that of the other growth stages. These results demonstrated that the distribution behaviors of mineral elements and heavy metals in horseradish can be affected by the type and concentration of REEs, and the growth period of plant.

  4. Perceived Barriers and Strategies to Effective Online Earth and Space Science Instruction

    ERIC Educational Resources Information Center

    Pottinger, James E.

    2012-01-01

    With the continual growth and demand of online courses, higher education institutions are attempting to meet the needs of today's learners by modifying and developing new student centered services and programs. As a result, faculty members are being forced into teaching online, including Earth and Space science faculty. Online Earth and Space…

  5. Investigation of Strategies to Promote Effective Teacher Professional Development Experiences in Earth Science

    ERIC Educational Resources Information Center

    Engelmann, Carol A.

    2014-01-01

    This dissertation serves as a call to geoscientists to share responsibility with K-12 educators for increasing Earth science literacy. When partnerships are created among K-12 educators and geoscientists, the synergy created can promote Earth science literacy in students, teachers, and the broader community. The research described here resulted in…

  6. Effect of the addition of low rare earth elements (lanthanum, neodymium, cerium) on the biodegradation and biocompatibility of magnesium.

    PubMed

    Willbold, Elmar; Gu, Xuenan; Albert, Devon; Kalla, Katharina; Bobe, Katharina; Brauneis, Maria; Janning, Carla; Nellesen, Jens; Czayka, Wolfgang; Tillmann, Wolfgang; Zheng, Yufeng; Witte, Frank

    2015-01-01

    Rare earth elements are promising alloying element candidates for magnesium alloys used as biodegradable devices in biomedical applications. Rare earth elements have significant effects on the high temperature strength as well as the creep resistance of alloys and they improve magnesium corrosion resistance. We focused on lanthanum, neodymium and cerium to produce magnesium alloys with commonly used rare earth element concentrations. We showed that low concentrations of rare earth elements do not promote bone growth inside a 750 μm broad area around the implant. However, increased bone growth was observed at a greater distance from the degrading alloys. Clinically and histologically, the alloys and their corrosion products caused no systematic or local cytotoxicological effects. Using microtomography and in vitro experiments, we could show that the magnesium-rare earth element alloys showed low corrosion rates, both in in vitro and in vivo. The lanthanum- and cerium-containing alloys degraded at comparable rates, whereas the neodymium-containing alloy showed the lowest corrosion rates.

  7. Effects of space plasma discharge on the performance of large antenna structures in low Earth orbit

    NASA Technical Reports Server (NTRS)

    Blume, Hans-Juergen C.

    1987-01-01

    The anomalous plasma around spacecrafts in low Earth orbit represents the coma of an artificial comet. The plasma discharge is caused by an energetic disturbance of charged particles which were formerly in a state of equilibrium. The plasma can effect the passive and active radio frequency operation of large space antennas by inducing corona discharge or strong arcing in the antenna feeds. One such large space antenna is the 15-meter hoop column antenna which consists of a mesh membrane material (tricot knitted gold plated wire) reflector and carbon fiber tension cords. The atomic oxygen in the plasma discharge state can force the wire base metal particles through the gold lattice and oxydize the metal particles to build a Schottky-barrier contact at the point where the wires meet. This effect can cause strong deviations in the reflector performance in terms of antenna pattern and losses. Also, the carbon-fiber cords can experience a strength reduction of 30 percent over a 40-hour exposure time.

  8. The effect of the earth's radiation belts on an optical system.

    PubMed

    Wolff, C

    1966-11-01

    A photoelectric optical imaging system has survived one year in the earth's radiation belts with no measurable (<20%) change in sensitivity. The system passes through all of the radiation belts twice every 64 hr, and experiences a noise level equivalent to 400 photons/sec when in their most intense regions. While this noise is far less than that of other photoelectric systems operating in the belts because of the small effective area of the photocathode, the noise per unit cathode area is 1.3 x 10(5) photons/sec-cm(2), and is similar to the best of the other systems. The number and energy distribution of incident particles is calculated and then combined with shielding estimates to give the total energy absorbed in the optical elements. Radiation damage reports in the literature are shown to be consistent with the lack of a sensitivity change in this orbiting optical system. The effects of particle radiation on optical systems in general is briefly summarized, with emphasis on recent work of others.

  9. The Effects of Solar Maximum on the Earth's Satellite Population and Space Situational Awareness

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2012-01-01

    The rapidly approaching maximum of Solar Cycle 24 will have wide-ranging effects not only on the number and distribution of resident space objects, but also on vital aspects of space situational awareness, including conjunction assessment processes. The best known consequence of high solar activity is an increase in the density of the thermosphere, which, in turn, increases drag on the vast majority of objects in low Earth orbit. The most prominent evidence of this is seen in a dramatic increase in space object reentries. Due to the massive amounts of new debris created by the fragmentations of Fengyun-1C, Cosmos 2251 and Iridium 33 during the recent period of Solar Minimum, this effect might reach epic levels. However, space surveillance systems are also affected, both directly and indirectly, historically leading to an increase in the number of lost satellites and in the routine accuracy of the calculation of their orbits. Thus, at a time when more objects are drifting through regions containing exceptionally high-value assets, such as the International Space Station and remote sensing satellites, their position uncertainties increase. In other words, as the possibility of damaging and catastrophic collisions increases, our ability to protect space systems is degraded. Potential countermeasures include adjustments to space surveillance techniques and the resetting of collision avoidance maneuver thresholds.

  10. Evaluation of Low-Earth-Orbit Environmental Effects on International Space Station Thermal Control Materials

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.

    1998-01-01

    Many spacecraft thermal control coatings in low Earth orbit (LEO) can be affected by solar ultraviolet radiation and atomic oxygen. Ultraviolet radiation can darken some polymers and oxides commonly used in thermal control materials. Atomic oxygen can erode polymer materials, but it may reverse the ultraviolet-darkening effect on oxides. Maintaining the desired solar absorptance for thermal control coatings is important to assure the proper operating temperature of the spacecraft. Thermal control coatings to be used on the International Space Station (ISS) were evaluated for their performance after exposure in the NASA Lewis Research Center's Atomic Oxygen-Vacuum Ultraviolet Exposure (AO-VUV) facility. This facility simulated the LEO environments of solar vacuum ultraviolet (VUV) radiation (wavelength range, 115 to 200 nanometers (nm)) and VUV combined with atomic oxygen. Solar absorptance was measured in vacuo to eliminate the "bleaching" effects of ambient oxygen on VUV-induced degradation. The objective of these experiments was to determine solar absorptance increases of various thermal control materials due to exposure to simulated LEO conditions similar to those expected for ISS. Work was done in support of ISS efforts at the requests of Boeing Space and Defense Systems and Lockheed Martin Vought Systems.

  11. Evaluation of Low Earth Orbit Environmental Effects on International Space Station Thermal Control Materials

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Rutledge, Sharon K.; Hasegawa, Mark M.; Reed, Charles K.

    1998-01-01

    Samples of International Space Station (ISS) thermal control coatings were exposed to simulated low Earth orbit (LEO) environmental conditions to determine effects on optical properties. In one test, samples of the white paint coating Z-93P were coated with outgassed products from Tefzel(R) (ethylene tetrafluoroethylene copolymer) power cable insulation as-may occur on ISS. These samples were then exposed, along with an uncontaminated Z-93P witness sample, to vacuum ultraviolet (VUV) radiation to determine solar absorptance degradation. The Z-93P samples coated with Tefzel(R) outgassing products experienced greater increases in solar absorptance than witness samples not coated with Tefzel(R) outgassing products. In another test, samples of second surface silvered Teflon(R) FEP (fluorinated ethylene propylene), SiO. (where x=2)-coated silvered Teflon(R) FEP, and Z-93P witness samples were exposed to the combined environments of atomic oxygen and VLTV radiation to determine optical properties changes due to these simulated ISS environmental effects. This test verified the durability of these materials in the absence of contaminants.

  12. Effect of Rare Earth Elements on Isothermal Transformation Kinetics in Si-Mn-Mo Bainite Steels

    NASA Astrophysics Data System (ADS)

    Liang, Yilong; Yi, Yanliang; Long, Shaolei; Tan, Qibing

    2014-12-01

    Isothermal heat treatments to Si-Mn-Mo steel specimens were performed, and time-temperature-transformation curves (C-curves) were plotted by DIL805A/D differential dilatometer. The effect of rare earth (RE) elements on bainite transformation kinetics was systematically studied by adopting the empirical electron theory of solids and molecules, Johnson-Mehl-Avrami equation calculation, dilatometry, and metallography. Experimental results show that the addition of RE in Si-Mn-Mo bainite steels leads to the C-curves moving to bottom right and prolongs incubation period of bainite transformation. Moreover, RE addition increases the values of phase structure factors ( n A, F {C/D}) and activation energy of bainite transformation, inhibits the formation of granular bainite, and refines microstructures of bainitic ferrite and substructures. During the bainite transformation process, bainite transformation is delayed due to the drag effect, which is induced by the segregation of RE at the ferrite interphase and the retardation of Fe-C-RE (segregation units) on carbon diffusion.

  13. Effect of thickness of liquefiable foundation on the seismic performance of earth dams

    NASA Astrophysics Data System (ADS)

    Berhe, Tensay; Wu, Wei

    2010-05-01

    Earthquake induced liquefaction continues to be a major threat to many civil engineering structures on the earth. Among these structures are earthfill dams. There are two major causes for the seismically inadequacy of a statically stable earthfill dams around the world. These are the liquefaction of the foundation layer and shell of the dams. In order to gain a better understanding of the seismic performance of earthfill dams on liquefiable foundation layer, a numerical model of an earthfill dam with mixed clay core founded on a liquefiable foundation subjected to earthquake is being studied. The properties and thickness of the liquefiable layer are varied to determine the related effects on the overlying earthfill dam. In order to explore the effect of the varying depth and thickness of liquefiable layer on the seismic response of earthfill dams, the total foundation thickness is divided into three equal layers so that the properties of each layer can be varied and studied. A finite difference numerical code, FLAC3D is used during the study. Results and discussions related to the significance of the depth and thickness of liquefiable layer in the foundation and resulting damage to the earthfill dam and hence the seismic performance of earthfill dam are presented. Keywords: Earthquake, liquefaction, earthfill dams, seismic performance, varying depth.

  14. Difluorenyl carbo-Benzenes: Synthesis, Electronic Structure, and Two-Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores.

    PubMed

    Baglai, Iaroslav; de Anda-Villa, Manuel; Barba-Barba, Rodrigo M; Poidevin, Corentin; Ramos-Ortíz, Gabriel; Maraval, Valérie; Lepetit, Christine; Saffon-Merceron, Nathalie; Maldonado, José-Luis; Chauvin, Remi

    2015-09-28

    The synthesis, crystal and electronic structures, and one- and two-photon absorption properties of two quadrupolar fluorenyl-substituted tetraphenyl carbo-benzenes are described. These all-hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the carbo-benzene core (C-C bonds for 3 a, C-C=C-C expanders for 3 b), exhibit quasi-superimposable one-photon absorption (1PA) spectra but different two-photon absorption (2PA) cross-sections σ2PA. Z-scan measurements (under NIR femtosecond excitation) indeed showed that the C≡C expansion results in an approximately twofold increase in the σ2PA value, from 336 to 656 GM (1 GM = 10(-50) cm(4) s molecule(-1) photon(-1)) at λ = 800 nm. The first excited states of Au and Ag symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum-over-state estimations of σ2PA(λi), in which λi = 2 hc/Ei, h is Planck's constant, c is the speed of light, and Ei is the energy of the 2PA-allowed transition. The calculated σ2PA values of 227 GM at 687 nm for 3 a and 349 GM at 708 nm for 3 b are in agreement with the Z-scan results.

  15. Research on Earth's rotation and the effect of atmospheric pressure on vertical deformation and sea level variability

    NASA Technical Reports Server (NTRS)

    Wahr, John

    1993-01-01

    The work done under NASA grant NAG5-485 included modelling the deformation of the earth caused by variations in atmospheric pressure. The amount of deformation near coasts is sensitive to the nature of the oceanic response to the pressure. The PSMSL (Permanent Service for Mean Sea Level) data suggest the response is inverted barometer at periods greater than a couple months. Green's functions were constructed to describe the perturbation of the geoid caused by atmospheric and oceanic loading and by the accompanying load-induced deformation. It was found that perturbation of up to 2 cm are possible. Ice mass balance data was used for continental glaciers to look at the glacial contributions to time-dependent changes in polar motion, the lod, the earth's gravitational field, the position of the earth's center-of-mass, and global sea level. It was found that there can be lateral, non-hydrostatic structure inside the fluid core caused by gravitational forcing from the mantle, from the inner core, or from topography at the core/mantle or inner core/outer core boundaries. The nutational and tidal response of a non-hydrostatic earth with a solid inner core was modeled. Monthly, global tide gauge data from PSMSL was used to look at the 18.6-year ocean tide, the 14-month pole tide, the oceanic response to pressure, the linear trend and inter-annual variability in the earth's gravity field, the global sea level rise, and the effects of post glacial rebound. The effects of mantle anelasticity on nutations, earth tides, and tidal variation in the lod was modeled. Results of this model can be used with Crustal Dynamics observations to look at the anelastic dissipation and dispersion at tidal periods. The effects of surface topography on various components of crustal deformation was also modeled, and numerical models were developed of post glacial rebound.

  16. Gravity effects on sediment sorting: limitations of models developed on Earth for Mars

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.; Kuhn, Brigitte; Gartmann, Andres

    2015-04-01

    Most studies on surface processes on planetary bodies assume that the use of empirical models developed for Earth is possible if the mathematical equations include all the relevant factors, such as gravity, viscosity and the density of water and sediment. However, most models for sediment transport on Earth are at least semi-empirical, using coefficients to link observed sediment movement to controlling factors such as flow velocity, slope and channel dimensions. However, using roughness and drag coefficients, as well as parameters describing incipient motion of particles, observed on Earth on another planet, violates, strictly speaking, the boundary conditions set for their application by fluid dynamics because the coefficienst describe a flow condition, not a particle property. Reduced gravity affects the flow around a settling partcile or over the bed of a watercourse, therefore data and models from Earth do not apply to another planet. Comparing observations from reduced gravity experiments and model results obtained on Earth confirm the significance of this error, e.g. by underestimating settling velocities of sandy particles by 10 to 50% for Mars when using models from Earth. In this study, the relevance of this error is examined by simulating the sorting of sediment deposited from water flowing on Mars. The results indicate that sorting on Mars is less pronounced than models calibrated on Earth suggest. This has implications for the selection of landing sites and, more importantly, the identification of strata potentially bearing traces of past life during rover missions on Mars.

  17. Gravity effects on sediment sorting: limitations of models developed on Earth for Mars

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.; Kuhn, B.; Gartmann, A.

    2015-10-01

    Most studies on surface processes on planetary bodies assume that the use of empirical models developed for Earth is possible if the mathematical equations include all the relevant factors, such as gravity, viscosity and the density of water and sediment. However, most models for sediment transport on Earth are at least semi-empirical, using coefficients to link observed sediment movement to controlling factors such as flow velocity, slope and channel dimensions. However, using roughness and drag coefficients, as well as parameters describing incipient motion of particles, observed on Earth on another planet, violates, strictly speaking, the boundary conditions set for their application by fluid dynamics because the coefficienst describe a flow condition, not a particle property. Reduced gravity affects the flow around a settling partcile or over the bed of a watercourse, therefore data and models from Earth do not apply to another planet. Comparing observations from reduced gravity experiments and model results obtained on Earth confirm the significance of this error, e.g. by underestimating settling velocities of sandy particles by 10 to 50% for Mars when using models from Earth. In this study, the relevance of this error is examined by simulating the sorting of sediment deposited from water flowing on Mars. The results indicate that sorting on Mars is less pronounced than models calibrated on Earth suggest. This has implications for the selection of landing sites and,more importantly, the identification of strata potentially bearing traces of past life during rover missions on Mars. try, 2001

  18. The Effect of Gender on the Attitudes of Undergraduates toward Young-Earth Creationism after Enrollment in an Origins Course

    ERIC Educational Resources Information Center

    Vinaja, Sean Stephen

    2016-01-01

    Many Christian students graduate from secondary schools and enter Christian colleges with worldviews that are unbiblical or contain unbiblical components, many of which stem from their beliefs regarding origins. Little research has been done to study the effect of gender on the role of a young-earth creationist (YEC) origins course in shaping…

  19. Rare earth elements (REEs): effects on germination and growth of selected crop and native plant species.

    PubMed

    Thomas, Philippe J; Carpenter, David; Boutin, Céline; Allison, Jane E

    2014-02-01

    The phytotoxicity of rare earth elements (REEs) is still poorly understood. The exposure-response relationships of three native Canadian plant species (common milkweed, Asclepias syriaca L., showy ticktrefoil, Desmodium canadense (L.) DC. and switchgrass, Panicum virgatum L.) and two commonly used crop species (radish, Raphanus sativus L., and tomato, Solanum lycopersicum L.) to the REEs lanthanum (La), yttrium (Y) and cerium (Ce) were tested. In separate experiments, seven to eight doses of each element were added to the soil prior to sowing seeds. Effects of REE dose on germination were established through measures of total percent germination and speed of germination; effects on growth were established through determination of above ground biomass. Ce was also tested at two pH levels and plant tissue analysis was conducted on pooled samples. Effects on germination were mostly observed with Ce at low pH. However, effects on growth were more pronounced, with detectable inhibition concentrations causing 10% and 25% reductions in biomass for the two native forb species (A. syriaca and D. canadense) with all REEs and on all species tested with Ce in both soil pH treatments. Concentration of Ce in aboveground biomass was lower than root Ce content, and followed the dose-response trend. From values measured in natural soils around the world, our results continue to support the notion that REEs are of limited toxicity and not considered extremely hazardous to the environment. However, in areas where REE contamination is likely, the slow accumulation of these elements in the environment could become problematic.

  20. Effects of trapped proton flux anisotropy on dose rates in low Earth orbit.

    PubMed

    Badhwar, G D; Kushin, V V; Akatov YuA; Myltseva, V A

    1999-06-01

    Trapped protons in the South Atlantic Anomaly (SAA) have a rather narrow pitch angle distribution and exhibit east-west anisotropy. In low Earth orbits, the E-W effect results in different amounts of radiation dose received by different sections of the spacecraft. This effect is best studied on missions in which the spacecraft flies in a fixed orientation. The magnitude of the effect depends on the particle energy and altitude through the SAA. In this paper, we describe a clear example of this effect from measurements of radiation dose rates and linear energy transfer spectra made on Space Shuttle flight STS-94 (28.5 degree inclination x 296 km altitude). The ratio of dose rates from the two directions at this location in the mid-deck was 2.7. As expected from model calculations, the spectra from the two directions are different, that is the ratio is energy dependent. The data can be used to distinguish the anisotropy models. The flight carried an active tissue equivalent proportional counter (TEPC), and passive thermoluminscent detectors (TLDs), and two types of nuclear emulsions. Using nuclear emulsions, charged particles and secondary neutron energy spectra were measured. The combined galactic cosmic radiation+trapped charged particle lineal energy spectra measured by the TEPC and the linear energy transfer spectrum measured by nuclear emulsions are in good agreement. The charged particle absorbed dose rates varied from 112 to 175 microGy/day, and dose equivalent rates from 264.3 to 413 microSv/day. Neutrons in the 1-10 MeV contributed a dose rate of 3.7 microGy/day and dose equivalent rate of 30.8 microSv/day, respectively.

  1. Effect of rare earth filtration on patient exposure, dose reduction, and image quality in oral panoramic radiology

    SciTech Connect

    Tyndall, D.A.; Washburn, D.B.

    1987-01-01

    Rare earth intensifying screen material (Gd2O2S:Tb) was added to the standard Al filtration of an oral panoramic x-ray unit, resulting in a beam capable of achieving reductions in patient dose without a loss of image quality. The added rare earth filtration technique resulted in patient dose reductions of 21-56%, depending on anatomic sites, when compared to the conventional Al filtration technique. Films generated from both techniques were measured densitometrically and evaluated by a panel of practicing clinicians. Diagnostically significant differences were minimal. The results indicate that use of rare earth filters in oral panoramic radiography is an effective means of reducing exposures of dental patients to ionizing radiation.

  2. Study of the effect of cloud inhomogeneity on the earth radiation budget experiment

    NASA Technical Reports Server (NTRS)

    Smith, Phillip J.

    1988-01-01

    The Earth Radiation Budget Experiment (ERBE) is the most recent and probably the most intensive mission designed to gather precise measurements of the Earth's radiation components. The data obtained from ERBE is of great importance for future climatological studies. A statistical study reveals that the ERBE scanner data are highly correlated and that instantaneous measurements corresponding to neighboring pixels contain almost the same information. Analyzing only a fraction of the data set when sampling is suggested and applications of this strategy are given in the calculation of the albedo of the Earth and of the cloud-forcing over ocean.

  3. The effect of Mars surface and Phobos propellant production on Earth launch mass

    NASA Technical Reports Server (NTRS)

    Babb, Gus R.; Stump, William R.

    1986-01-01

    Fuel and oxidizer produced on the surface of Mars and on the Martian Moon Phobos can reduce the cumulative mass of fuel and oxidizer which must be launched to low Earth orbit for Mars exploration missions. A scenario in which ten conjunction class trajectory missions over a twenty year period land a surface base and propellant production facilities on the Martian surface and on Phobos was examined. Production of oxygen on Phobos provides the greatest benefit. If all the propellant for Mars operations and Earth return is produced at Phobos and on Mars, a 30% reduction in cumulative low Earth orbit mass can be achieved at the end of the 20 year period.

  4. Effects of polar ice on the earth's rotation and gravitational potential

    NASA Technical Reports Server (NTRS)

    Trupin, Andrew S.

    1993-01-01

    The contributions of the Antarctic and the Greenland ice sheets to the earth's gravity, displacement, and rotation are estimated using gridded values of the net surface accumulation rates in the ice sheets of these two regions. It is found that the contributions to the low-order zonal harmonic coefficients of the earth's gravitational potential from Antarctica are between 2 and 10 times larger than the uncertainties of the zonal harmonics derived from satellite solutions; for Greenland, the coefficients are within an order of magnitude of the uncertainties of the satellite solutions. Polar contributions to the displacement of the center of mass of the solid earth, as seen in the frame of reference of satellites tracked from the earth surface, range from less than 1 mm to 1.5 cm over a 60-yr period.

  5. Effect of low doses of dietary rare earth elements on growth performance of broilers.

    PubMed

    He, M L; Wehr, U; Rambeck, W A

    2010-02-01

    The present study was designed to investigate effect of dietary rare earth elements (REE), including both organic and inorganic compounds, on growth performance of broilers. In experiment 1, a total of 180 male Ross broiler chicks were allocated to 72 pens with different assignment: four chicks per pen or individually. The following three treatment diets were applied: control, REE-chlorides at a dose of 40 mg/kg and REE-citrate at a dose of 70 mg/kg. Each treatment group had 24 pens containing both assignments (12 pens each). In experiment 2, a total of 72 male 3-day-old Ross broiler chicks were separated to four groups: control, REE-chlorides at a dose of 70 mg/kg and REE-citrate at doses of 70 mg/kg and 100 mg/kg. In experiment 1, dietary REE-citrate improved body weight gain during the overall period by 5.0% (p < 0.05) while the increase with REE-chloride was not significant. In experiment 2, growth effects (p < 0.05) were only found in the period from day 21 to slaughter with all REE forms, and feed conversion ratio was improved by 3.4% (p < 0.05) with REE-citrate. No significant effects of REE were found on chill weight, percentages of breast meat, thigh weight, drumstick weight and wing weight. Concentrations of La and Ce in the liver and muscles were very low, accounting for 0.11-0.76 and 0.02-0.30 mg/kg respectively. There was weak tendency for a dose-response relationship especially in the groups supplemented with REE-chlorides. The main blood serum biochemical parameters were not significantly affected by REE in the diets. The results suggest that dietary supplementation of low doses of REE-citrates might improve growth performance of broilers without affecting carcass composition and health of the broilers.

  6. A mathematical characterization of vegetation effect on microwave remote sensing from the Earth

    NASA Technical Reports Server (NTRS)

    Choe, Y.; Tsang, L.

    1983-01-01

    In passive microwave remote sensing of the earth, a theoretical model that utilizes the radiative transfer equations was developed to account for the volume scattering effects of the vegetation canopy. Vegetation canopies such as alfalfa, sorghum, and corn are simulated by a layer of ellipsoidal scatterers and cylindrical structures. The ellipsoidal scatterers represent the leaves of vegetation and are randomly positioned and oriented. The orientation of ellipsoids is characterized by a probability density function of Eulerian angles of rotation. The cylindrical structures represent the stalks of vegetation and their radii are assumed to be much smaller than their lengths. The underlying soil is represented by a half-space medium with a homogeneous permittivity and uniform temperature profile. The radiative transfer quations are solved by a numerical method using a Gaussian quadrature formula to compute both the vertical and horizontal polarized brightness temperature as a function of observation angle. The theory was applied to the interpretation of experimental data obtained from sorghum covered fields near College Station, Texas.

  7. A third-order theory for the effect of drag on earth satellite orbits

    NASA Astrophysics Data System (ADS)

    Sharma, Ram K.

    1992-09-01

    Analytical theory for the motion of near-earth satellite orbits with the air drag effect is developed in terms of the KS elements, utilizing an analytical oblate exponential atmospheric model. The series expansions include up to cubic terms in e (eccentricity) and c(a small parameter dependent on the flattening of the atmosphere). Due to the symmetry of the KS element equations, only one of the eight equations is integrated analytically to obtain the state vector at the end of each revolution. Numerical comparisons are made with nine test cases, selected to cover a wide range of eccentricity with perigee heights near to 300 km at three different inclinations. A comparison of three orbital parameters: semi-major axis, eccentricity and argument of perigee, perturbed by air drag with oblate atmosphere is made with the previously developed second-order theory. It is found that with the present theory with increase in eccentricity there is improvement in semi-major axis and eccentricity computations over the second-order theory.

  8. Snow load effect on earth's rotation and gravitational field, 1979-1985

    NASA Technical Reports Server (NTRS)

    Chao, B. Fong; O'Connor, William P.; Chang, Alfred T. C.; Hall, Dorothy K.; Foster, James L.

    1987-01-01

    A global, monthly snow depth data set has been generated from the Nimbus 7 satellite observations using passive microwave remote-sensing techniques. Seven years of data, 1979-1985, are analyzed to compute the snow load effects on the earth's rotation and low-degree zonal gravitational field. The resultant time series show dominant seasonal cycles. The annual peak-to-peak variation in J2 is found to be 2.3 x 10 to the -10th, that in J3 to be 1.1 x 10 to the -10th, and believed to decrease rapidly for higher degrees. The corresponding change in the length of day is 41 micro-s. The annual wobble excitation is (4.9 marc sec, -109 deg) for the prograde motion component and (4.8 marc sec, -28 deg) for the retrograde motion component. The excitation power of the Chandler wobble due to the snow load is estimated to be about 25 dB less than the power needed to maintain the observed Chandler wobble.

  9. Crystal electric field effects and thermal expansion of rare-earth hexaborides

    NASA Astrophysics Data System (ADS)

    Novikov, V. V.; Pilipenko, E. S.; Bud'ko, S. L.

    2017-02-01

    Anomalies in the magnetic contribution to the thermal expansion coefficients ∆β(T)of the CeB6, PrB6, and NdB6 hexaborides in the range of 5-300 K were found by comparison with diamagnetic LaB6. The characteristic of the anomalies was the same in all the studied borides: a distinct peak at low temperatures, followed by a broad maximum at higher temperatures (50-100 K), then a decrease and transition to the region of negative values as the temperature increases further. The features of ∆β(T) are explained by the effects of the magnetic order (sharp low temperature peaks) and the crystal electric field (CEF). The βCEF(T) dependencies were calculated using Raman and neutron scattering data on the splitting of the rare-earth (RE) ions R3+ f-level by the CEF. A satisfactory consistency between the values of βCEF(T) and ∆β(T)was obtained for the studied hexaborides. Additionally, we determined the values of the Grüneisen parameter γi that correspond to the transition between the ground and excited multiplets of R3+ ions f-level splitting.

  10. A study of students' perceptions of the organisation and effectiveness of fieldwork in earth sciences education

    NASA Astrophysics Data System (ADS)

    Marques, Luis; Praia, Joa¨O.; Kempa, Richard

    2003-02-01

    This paper reports the findings of a preliminary evaluation of an in-service training programme designed for practising geology/earth science teachers in Portuguese high schools and intended to enhance the effectiveness of fieldwork activities organised by them for their students. Among the points particularly stressed during the in-service training were that students should be adequately prepared for fieldwork through classroom-based activities prior to the fieldwork itself and that to arrive at the maximum educational benefit for the students, they should be involved in collaborative group-based investigation. The findings, derived from an enquiry among students following their exposure to fieldwork, revealed that in both these aspects teachers failed to put theory into practice, probably as the result of a lack of confidence to implement novel procedures. On the positive side, the students reported that they enjoyed the social interaction with other students that the fieldwork made possible and the opportunity to work independently of the teachers.

  11. The effect of cloud type on earth's energy balance - Results for selected regions

    NASA Technical Reports Server (NTRS)

    Ockert-Bell, Maureen E.; Hartmann, Dennis L.

    1992-01-01

    International Satellite Cloud Climatology Project (ISCCP) C1 cloud information is compared with planetary albedo, outgoing longwave radiation (OLR), and net radiation measured at the top of the atmosphere by the Earth Radiation Budget Experiment (ERBE). Principal component analysis indicates that the day-to-day variations of the abundances of the 35 cloud types of the C1 data are correlated with each other, so that for many purposes the data set can be well represented by about five cloud types. Using stepwise multiple regression, the ISCCP C1 data can be used to predict the day-to-day variations of the energy balance measured by ERBE for 2.5-deg regions. Total fractional area coverage of cloudiness is a relatively poor predictor of radiation budget quantities. If the total fractional area coverage by clouds is divided into contributions from several distinct cloud types, the fractional coverages by these several cloud types will together form a much better prediction of radiation budget quantities than the single variable of total fractional-area cloud coverage. The regression equations can be used to estimate the net effect of clouds on the radiation balance and the contributions from particular types of clouds to albedo, OLR, and net radiation.

  12. Effects of DeOrbitSail as applied to Lifetime predictions of Low Earth Orbit Satellites

    NASA Astrophysics Data System (ADS)

    Afful, Andoh; Opperman, Ben; Steyn, Herman

    2016-07-01

    Orbit lifetime prediction is an important component of satellite mission design and post-launch space operations. Throughout its lifetime in space, a spacecraft is exposed to risk of collision with orbital debris or operational satellites. This risk is especially high within the Low Earth Orbit (LEO) region where the highest density of space debris is accumulated. This paper investigates orbital decay of some LEO micro-satellites and accelerating orbit decay by using a deorbitsail. The Semi-Analytical Liu Theory (SALT) and the Satellite Toolkit was employed to determine the mean elements and expressions for the time rates of change. Test cases of observed decayed satellites (Iridium-85 and Starshine-1) are used to evaluate the predicted theory. Results for the test cases indicated that the theory fitted observational data well within acceptable limits. Orbit decay progress of the SUNSAT micro-satellite was analysed using relevant orbital parameters derived from historic Two Line Element (TLE) sets and comparing with decay and lifetime prediction models. This paper also explored the deorbit date and time for a 1U CubeSat (ZACUBE-01). The use of solar sails as devices to speed up the deorbiting of LEO satellites is considered. In a drag sail mode, the deorbitsail technique significantly increases the effective cross-sectional area of a satellite, subsequently increasing atmospheric drag and accelerating orbit decay. The concept proposed in this study introduced a very useful technique of orbit decay as well as deorbiting of spacecraft.

  13. Effects of the Large June 1975 Meteoroid Storm on Earth's Ionosphere.

    PubMed

    Kaufmann, P; Kuntz, V L; Leme, N M; Piazza, L R; Boas, J W; Brecher, K; Crouchley, J

    1989-11-10

    The June 1975 meteoroid storm detected on the moon by the Apollo seismometers was the largest ever observed. Reexamination of radio data taken at that time showed that the storm also produced pronounced disturbances on Earth, which were recorded as unique phase anomalies on very low frequency (VLF) radio propagation paths in the low terrestrial ionosphere. Persistent effects were observed for the major storm period (20 to 30 June 1975), including reductions in the diurnal phase variation, advances in the nighttime and daytime phase levels, and reductions in the sunset phase delay rate. Large nighttime phase advances, lasting a few hours, were detected on some days at all VLF transmissions, and for the shorter propagation path they were comparable to solar Lyman alpha daytime ionization. Ion production rates attributable to the meteor storm were estimated to be about 0.6 to 3.0 ions per centimeter cubed per second at the E and D regions, respectively. The storm was a sporadic one with a radiant (that is, the point of apparent origin in the sky) located in the Southern Hemisphere, with a right ascension 1 to 2 hours larger than the sun's right ascension.

  14. Effect of knowledge integration activities on students' perception of the earth's crust as a cyclic system

    NASA Astrophysics Data System (ADS)

    Kali, Yael; Orion, Nir; Eylon, Bat-Sheva

    2003-08-01

    Systems thinking is regarded as a high-order thinking skill required in scientific, technological, and everyday domains. However, little is known about systems thinking in the context of science education. In the current research, students' understanding of the rock cycle system after a learning program was characterized, and the effect of a concluding knowledge integration activity on their systems thinking was studied. Answers to an open-ended test were interpreted using a systems thinking continuum, ranging from a completely static view of the system to an understanding of the system's cyclic nature. A meaningful improvement in students' views of the rock cycle toward the higher side of the systems thinking continuum was found after the knowledge integration activity. Students became more aware of the dynamic and cyclic nature of the rock cycle, and their ability to construct sequences of processes representing material transformation in relatively large chunks significantly improved. Success of the knowledge integration activity stresses the importance of postknowledge acquisition activities, which engage students in a dual process of differentiation of their knowledge and reintegration in a systems context. We suggest including such activities in curricula involving systems-based contents, particularly in earth science, in which systems thinking can bring about environmental literacy.

  15. The insecticidal effect of diatomaceous earth against adults and nymphs of Blattella germanica

    PubMed Central

    Hosseini, Seyyed Akbar; Bazrafkan, Sahar; Vatandoost, Hassan; Abaei, Mohammad Reza; Ahmadi, Mussa Soleimani; Tavassoli, Maryam; Shayeghi, Mansoreh

    2014-01-01

    Objective To evaluate the insecticidal effect of diatomaceous earth (DE) against adults and nymphs of Blattella germanica. Methods This cross sectional study has been done on the laboratory strain of German cockroaches. Two stages, nymph and adult, were exposed to six dose rates of the DE, 2.5, 5, 10, 15, 20 and 25 g/m2, at 24, 48 and 72 h exposure period. Mortality (number of dead cockroaches) was assessed after 24 h. Other exposed specimens were transferred to the beakers contained food and water for counting the retard mortality rate after 1 week. Results Increasing in dose rates of DE increased mortality rate, so that the lowest and highest mortality rates were observed in 2.5 and 25 g/m2, respectively. The results of the statistical analysis showed no significant difference in the lethality of 50% of DE plus water on the German cockroach nymphs. Conclusions Due to the resistance of German cockroach against organochloride, organophosphorus, carbamate and pyrethriodes insecticides, it is suggested to use DE for insect's control. PMID:25183087

  16. Mixed alkali effect on the spectroscopic properties of alkali-alkaline earth oxide borate glasses

    NASA Astrophysics Data System (ADS)

    Srinivas, G.; Ramesh, B.; Shareefuddin, Md.; Chary, M. N.; Sayanna, R.

    2016-05-01

    The mixed alkali and alkaline earth oxide borate glass with the composition xK2O - (25-x) Li2O-12.5BaO-12.5MgO-50B2O3 (x = 0, 5, 10, 15, 20 and 25mol %) and doped with 1mol% CuO were prepared by the melt quenching technique. From the optical absorption spectra the optical band gap, electronic polarizability(α02-), interaction parameter (A), theoretical and experimental optical basicity (Λ) values were evaluated. From the Electron Paramagnetic Resonance (EPR) spectral data the number of spins (N) and susceptibility (χ) were evaluated. The values of (α02-), and (Λ) increases with increasing of K2O content and electronic polarizability and interaction parameter show opposite behaviuor which may be due to the creation of non-bridging oxygens and expansion of borate network. The reciprocal of susceptibility (1/χ) and spin concentration (N) as a function of K2O content, varied nonlinearly which may be due to creation of non-bridging oxygens in the present glass system. This may be attributed to mixed alkali effect (MAE).

  17. New estimates of the Earth radiation budget under cloud-free conditions and cloud radiative effects

    NASA Astrophysics Data System (ADS)

    Wild, Martin; Hakuba, Maria Z.; Folini, Doris; Schär, Christoph; Long, Charles

    2017-02-01

    In previous studies1, 2 we derived new estimates for the magnitude of the components of the global mean energy budget using to the extent possible the information contained in direct observations from surface and space. Here we establish complementary estimates for the global mean energy budget specifically under cloud-free conditions. The energy fluxes under cloud-free conditions at the Top of Atmosphere (TOA) can be determined with high accuracy from satellite measurements (CERES-EBAF). For the estimation of their counterparts at the Earth's surface we follow the approach presented in our recent studies, based on an analysis of 39 state of the art global climate models from CMIP5 and their bias structure compared to a comprehensive set of high quality surface observations from the Baseline Surface Radiation Network (BSRN). Thereby we infer a best estimate of 249 Wm-2 for the global mean clear-sky downward shortwave radiation at the surface, and a corresponding clear-sky surface shortwave absorption of 216 Wm-2, considering a global mean surface albedo of 13 %. Combined with a best estimate for the global mean net shortwave influx at the TOA under cloud-free skies from CERES-EBAF of 287 Wm-2, this leaves an amount of 71 Wm-2 absorbed shortwave radiation in the cloud-free atmosphere. The 71 Wm-2 coincide with our earlier estimate for this quantity in Wild et al. (2006)3 based on older models and fewer direct observations, suggesting that this estimate is fairly robust. For the clear-sky downward longwave radiation at the Earth surface we obtain a best estimate of 314 Wm-2. A comparison of the clear-sky global energy balance diagram presented here with the corresponding all-sky diagram established in our previous studies enables a quantification of the global mean shortwave, longwave and net cloud-radiative effects at the TOA, within the atmosphere and at the surface, as well as an assessment of their representation in climate models.

  18. The effects of continental block configuration on the Earth's heat loss

    NASA Astrophysics Data System (ADS)

    Cooper, C. M.; Moresi, L. N.; Lenardic, A.

    2012-12-01

    The presence of continents on the Earth's surface produces an unusual convective system with parallel mechanisms for losing internal heat: conduction through the stable, continental insulating lid, and a more efficient balance of horizontal advection and vertical conduction in the actively overturning oceanic thermal boundary layer. The resulting thermal network which describes the heat loss behavior of the combined mechanisms can create a buffer which moderates the insulating effect of the continental lid on the Earth's overall heat loss, but only if the deep mantle flow communicates between sub-continental and sub-oceanic regions. If communication is disconnected between the two heat transfer mechanisms, then the continent locally insulates the mantle beneath it causing the subcontinental mantle temperature to increase compared to the sub-oceanic mantle setting the stage for a different global impact on mantle dynamics. The thermal-network theory which describes the two end-member cases does not directly constrain the cross-over between these states; however, the configuration of the insulating lid is expected to play a major role. Here we extend previous 2D work to include multiple continental blocks in various configurations to determine when the mixed-network theory holds and when thermal isolated modes can be produced. The continental blocks were arranged in three configurations while holding the total surface area covered by the blocks constant. The three possible layouts were: (1) a single block centered in the model domain, (2) two blocks of equal size centered in the model domain or (3) four blocks of equal size centered in the 3x3x1 Cartesian model domain. All continental blocks are fixed to the coordinate system; when apart (in the two or four block configuration), the blocks do not move relative to each other, but the mantle is free to move dynamically in all directions via periodic boundary conditions. The total surface area covered by continental

  19. Effect of the Earth's inner structure on the gravity in definitions of height systems

    NASA Astrophysics Data System (ADS)

    Tenzer, Robert; Foroughi, Ismael; Pitoňák, Martin; Šprlák, Michal

    2017-01-01

    SUMMARYIn context of the vertical datum unification, the geoid-to-quasigeoid separation has been of significant interest in recent years, because most of existing local vertical datums are realized in the system of either normal or orthometric heights. Nevertheless, the normal-orthometric heights are still used in many other countries where the normal gravity values along leveling lines were adopted instead of the observed gravity. Whereas the conversion between the orthometric and normal heights is defined by means of the mean gravity disturbances (i.e., differences between the mean values of the actual and normal gravity) along the plumbline within the topography, differences between the normal and normal-orthometric heights can be described by means of the surface gravity disturbances. Since the normal gravity field does not reflect the topographic masses and actual mass density distribution inside the <span class="hlt">Earth</span>, the definition of gravity represents a principal aspect for a realization of particular vertical datum. To address this issue in this study we investigate <span class="hlt">effects</span> of the <span class="hlt">Earth</span>'s inner density structure on the surface and mean gravity disturbances, and discuss their impact on the vertical datum realization. These two gravity field quantities are computed globally with a spectral resolution complete to a spherical harmonic degree 2160 using the global gravity, terrain, ice-thickness, inland bathymetry and crustal structure models. Our results reveal that both, the surface and mean gravity disturbances mostly comprise the gravitational signal of topography and masses distributed below the geoid surface. Moreover, in polar areas a significant contribution comes from large glaciers. In contrast, the contributions of anomalous density distribution within the topography attributed to major lakes, sediments and bedrock density variations are much less pronounced. We also demonstrate that the mean gravity disturbances within the topography are significantly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986ASSL..127..129P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986ASSL..127..129P"><span id="translatedtitle">On the possibility of a 'cuckoo-<span class="hlt">effect</span>' in the <span class="hlt">earth</span>-moon system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pauwels, T.</p> <p></p> <p>In this paper an investigation is made of the possibility that the moon could have depleted the <span class="hlt">earth</span> satellite system of all natural satellites by a combination of orbit-orbit resonances and tidal evolution. Simulations show that for a satellite closer than 150 <span class="hlt">earth</span> radii, avoiding all resonances is definitely impossible, but it can be captured in a stable resonant orbit as well as in a resonant orbit leading to a close approach to the moon.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=earth+AND+resource&pg=3&id=EJ025063','ERIC'); return false;" href="http://eric.ed.gov/?q=earth+AND+resource&pg=3&id=EJ025063"><span id="translatedtitle"><span class="hlt">Earth</span> Resources</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Brewer, Tom</p> <p>1970-01-01</p> <p>Reviews some of the more concerted, large-scale efforts in the <span class="hlt">earth</span> resources areas" in order to help the computer community obtain insights into the activities it can jointly particpate in withthe <span class="hlt">earth</span> resources community." (Author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28294267','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28294267"><span id="translatedtitle">Nucleation-dependant chemical bonding paradigm: the <span class="hlt">effect</span> of rare <span class="hlt">earth</span> ions on the nucleation of urea in aqueous solution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Xiaoyan; Sun, Congting; Wu, Sixin; Xue, Dongfeng</p> <p>2017-03-29</p> <p>Rare <span class="hlt">earth</span> ions can be used to construct a variety of novel structures and are favorable to chemical bonding regulation and design. In this study, the chemical bonding paradigm between rare <span class="hlt">earth</span> ions (Ln(3+)) and urea molecules in an aqueous solution can be tracked by the evolution of C[double bond, length as m-dash]O, NH2, and CN vibration bands during the urea nucleation stage. Rare <span class="hlt">earth</span> ions such as La(3+), Gd(3+), and Lu(3+) can manipulate the nucleation time of urea via regulating the nucleation-dependant N-C[double bond, length as m-dash]OH-N hydrogen-bonding between urea molecules. Two types of chemical bondings between Ln(3+) and urea molecules have been confirmed, which are Ln(3+)O[double bond, length as m-dash]C-N and Ln(3+)NH2-C. Compared with Ln(3+)NH2-C, Ln(3+) prefers to coordinate with the O[double bond, length as m-dash]C bond in urea. With a higher concentration of rare <span class="hlt">earth</span> ions in the solution, some N-C[double bond, length as m-dash]OH-N hydrogen bonds are broken as a consequence of the incorporation of Ln(3+) into the lattice, resulting in the decreased symmetry of local urea molecules in the crystalline nuclei and the consequent Ln(3+) concentration-dependent nucleation time of urea. Moreover, using the ionic electronegativity scale of Ln(3+), the different <span class="hlt">effects</span> of La(3+), Gd(3+), and Lu(3+) on urea nucleation can be further distinguished. The present study provides basic data for unrevealing the chemical bonding regulation role of rare <span class="hlt">earth</span> ions in the formation of hydrogen bonded materials, which may give insight into the design and fabrication of novel materials utilizing rare <span class="hlt">earth</span> ions to adjust the chemical bonding process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930001397','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930001397"><span id="translatedtitle">Space environmental <span class="hlt">effects</span> on LDEF low <span class="hlt">Earth</span> orbit exposed graphite reinforced polymer matrix composites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>George, Pete</p> <p>1992-01-01</p> <p>The Long Duration Exposure Facility (LDEF) was deployed on April 7, 1984 in low <span class="hlt">earth</span> orbit (LEO) at an altitude of 482 kilometers. On board experiments experienced the harsh LEO environment including atomic oxygen (AO), ultraviolet radiation (UV), and thermal cycling. During the 5.8 year mission, the LDEF orbit decayed to 340 kilometers where significantly higher AO concentrations exist. LDEF was retrieved on January 12, 1990 from this orbit. One experiment on board LDEF was M0003, Space <span class="hlt">Effects</span> on Spacecraft Materials. As a subset of M0003 nearly 500 samples of polymer, metal, and glass matrix composites were flown as the Advanced Composites Experiment M0003-10. The Advanced Composites Experiment is a joint effort between government and industry with the Aerospace Corporation serving as the experiment integrator. A portion of the graphite reinforced polymer matrix composites were furnished by the Boeing Defense and Space Group, Seattle, Washington. Test results and discussions for the Boeing portion of M0003-10 are presented. Experiment and specimen location on the LDEF are presented along with a quantitative summary of the pertinent exposure conditions. Matrix materials selected for the test were epoxy, polysulfone, and polyimide. These composite materials were selected due to their suitability for high performance structural capability in spacecraft applications. Graphite reinforced polymer matrix composites offer higher strength to weight ratios along with excellent dimensional stability. The Boeing space exposed and corresponding ground control composite specimens were subjected to post flight mechanical, chemical, and physical testing in order to determine any changes in critical properties and performance characteristics. Among the more significant findings are the erosive <span class="hlt">effect</span> of atomic oxygen on leading edge exposed specimens and microcracking in non-unidirectionally reinforced flight specimens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9915E..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9915E..08S"><span id="translatedtitle">The <span class="hlt">effect</span> of proton radiation on the EMCCD for a low <span class="hlt">Earth</span> orbit satellite mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Ken; Daigle, Olivier; Scott, Alan; Piche, Louis; Hudson, Danya</p> <p>2016-08-01</p> <p>We report on the proton radiation <span class="hlt">effects</span> on a 1k x 1k e2v EMCCD utilized in the Nüvü EM N2 1024 camera. Radiation testing was performed at the TRIUMF Proton Irradiation Facility in Canada, where the e2v CCD201-20 EMCCD received a 105 MeV proton fluence up to 5.2x109 protons/cm2, emulating a 1 year's radiation dose of solar protons in low <span class="hlt">earth</span> orbit with nominal shielding that would be expected from a small or microsatellite. The primary space-based application is for Space Situational Awareness (SSA), where a small telescope images faint orbiting Resident Space Objects (RSOs) on the EMCCD, resulting in faint streaks at the photon level of signal in the images. Of particular concern is the <span class="hlt">effect</span> of proton radiation on low level CTE, where very low level signals could be severely impaired if not lost. Although other groups have reported on the characteristics of irradiated EMCCDs, their CTE results are not portable to this application. To understand the real impact of proton irradiation the device must be tested under realistic operating conditions with representative backgrounds, clock periods, and signal levels. Testing was performed both in the laboratory and under a night sky on the ground in order to emulate a complex star background environment containing RSOs. The degradation is presented and mitigation techniques are proposed. As compared to conventional CCDs, the EMCCD with high gain allows faint and moving RSOs to be detected with a relatively small telescope aperture, at improved signal to noise ratio at high frame rates. This allows the satellite platform to take sharp images immediately upon slewing to the target without the need for complex and relatively slow attitude stabilization systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3367923','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3367923"><span id="translatedtitle"><span class="hlt">Effect</span> of Rare <span class="hlt">Earth</span> Ions on the Properties of Composites Composed of Ethylene Vinyl Acetate Copolymer and Layered Double Hydroxides</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Lili; Li, Bin; Zhao, Xiaohong; Chen, Chunxia; Cao, Jingjing</p> <p>2012-01-01</p> <p>Background The study on the rare <span class="hlt">earth</span> (RE)-doped layered double hydroxides (LDHs) has received considerable attention due to their potential applications in catalysts. However, the use of RE-doped LDHs as polymer halogen-free flame retardants was seldom investigated. Furthermore, the <span class="hlt">effect</span> of rare <span class="hlt">earth</span> elements on the hydrophobicity of LDHs materials and the compatibility of LDHs/polymer composite has seldom been reported. Methodology/Principal Findings The stearate sodium surface modified Ni-containing LDHs and RE-doped Ni-containing LDHs were rapidly synthesized by a coprecipitation method coupled with the microwave hydrothermal treatment. The influences of trace amounts of rare <span class="hlt">earth</span> ions La, Ce and Nd on the amount of water molecules, the crystallinity, the morphology, the hydrophobicity of modified Ni-containing LDHs and the adsorption of modifier in the surface of LDHs were investigated by TGA, XRD, TEM, contact angle and IR, respectively. Moreover, the <span class="hlt">effects</span> of the rare <span class="hlt">earth</span> ions on the interfacial compatibility, the flame retardancy and the mechanical properties of ethylene vinyl acetate copolymer (EVA)/LDHs composites were also explored in detail. Conclusions/Significance S-Ni0.1MgAl-La displayed more uniform dispersion and better interfacial compatibility in EVA matrix compared with other LDHs. Furthermore, the S-Ni0.1MgAl-La/EVA composite showed the best fire retardancy and mechanical properties in all composites. PMID:22693627</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1542..281J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1542..281J"><span id="translatedtitle"><span class="hlt">Effect</span> of inter-particle rolling resistance on passive <span class="hlt">earth</span> pressure against a translating rigid retaining wall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Mingjing; He, Jie; Liu, Fang; Wang, Huaning</p> <p>2013-06-01</p> <p>The presence of the inter-particle rolling resistance of soil grains results in higher bulk shear strength in the soil, which relates to the <span class="hlt">earth</span> pressure calculation based on the classic theory. This paper focuses on the <span class="hlt">effect</span> of the inter-particle rolling resistance on the <span class="hlt">earth</span> pressure against a rigid retaining wall. A particle contact model considering the inter-particle rolling resistance was implemented into the distinct element code PFC2D, which was then used to simulate a rigid wall retaining a sandy backfill. The passive <span class="hlt">earth</span> pressure against the wall subjected to a translational displacement was analyzed and compared with results without considering the inter-particle rolling resistance. The influence of the inter-particle rolling resistance was examined from the microscopic scale (e.g., averaged micro-pure rotation-rate) as well as the macroscopic scale (e.g., the magnitude and action point of resultant <span class="hlt">earth</span> pressures). The results show that the inter-particle rolling resistance of the backfill strongly affects the value of passive thrust behind the wall, but it has no significant <span class="hlt">effect</span> on the action position of the thrust. The distribution of micro-pure rotation-rate (APR) in the backfill provides an insight into the connection between inter-particle rolling resistance to the energy dissipation in the shear zone behind the wall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdSpR..56..494G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdSpR..56..494G"><span id="translatedtitle"><span class="hlt">Earth</span>'s gravity gradient and eddy currents <span class="hlt">effects</span> on the rotational dynamics of space debris objects: Envisat case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gómez, Natalia Ortiz; Walker, Scott J. I.</p> <p>2015-08-01</p> <p>The space debris population has grown rapidly over the last few decades with the consequent growth of impact risk between current objects in orbit. Active Debris Removal (ADR) has been recommended to be put into practice by several National Agencies in order to remove objects that pose the biggest risk for the space community. The most immediate target that is being considered for ADR by the European Space Agency is the <span class="hlt">Earth</span>-observing satellite Envisat. In order to safely remove such a massive object from its orbit, a capturing process followed by a controlled reentry is necessary. However, current ADR methods that require physical contact with the target have limitations on the maximum angular momentum that can be absorbed and a de-tumbling phase prior to the capturing process may be required. Therefore, it is of utmost importance for the ADR mission design to be able to predict accurately how the target will be rotating at the time of capture. This article analyses two perturbations that affect an object in Low <span class="hlt">Earth</span> Orbit (LEO), the <span class="hlt">Earth</span>'s gravity gradient and the eddy currents induced by the <span class="hlt">Earth</span>'s magnetic field. The gravity gradient is analysed using the equation of conservation of total energy and a graphical method is presented to understand the expected behaviour of any object under the <span class="hlt">effect</span> of this perturbation. The eddy currents are also analysed by studying the total energy of the system. The induced torque and the characteristic time of decay are presented as a function of the object's magnetic tensor. In addition, simulations were carried out for the Envisat spacecraft including the gravity gradient perturbation as well as the eddy currents <span class="hlt">effect</span> using the International Geomagnetic Reference Field IGRF-11 to model the <span class="hlt">Earth</span>'s magnetic field. These simulations show that the combined <span class="hlt">effect</span> of these two perturbations is a plausible explanation for the rotational speed decay observed between April 2013 and September 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800012239','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800012239"><span id="translatedtitle"><span class="hlt">Earth</span> survey applications division: Research leading to the <span class="hlt">effective</span> use of space technology in applications relating to the <span class="hlt">Earth</span>'s surface and interior</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carpenter, L. (Editor)</p> <p>1980-01-01</p> <p>Accomplishments and future plans are described for the following areas: (1) geology - geobotanical indicators and geopotential data; (2) modeling magnetic fields; (3) modeling the structure, composition, and evolution of the <span class="hlt">Earth</span>'s crust; (4) global and regional motions of the <span class="hlt">Earth</span>'s crust and earthquake occurrence; (5) modeling geopotential from satellite tracking data; (6) modeling the <span class="hlt">Earth</span>'s gravity field; (7) global <span class="hlt">Earth</span> dynamics; (8) sea surface topography, ocean dynamics; and geophysical interpretation; (9) land cover and land use; (10) physical and remote sensing attributes important in detecting, measuring, and monitoring agricultural crops; (11) prelaunch studies using LANDSAT D; (12) the multispectral linear array; (13) the aircraft linear array pushbroom radiometer; and (14) the spaceborne laser ranging system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MMTA...46.1168M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MMTA...46.1168M"><span id="translatedtitle">Cyclic Deformation Behavior of a Rare-<span class="hlt">Earth</span> Containing Extruded Magnesium Alloy: <span class="hlt">Effect</span> of Heat Treatment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mirza, F. A.; Chen, D. L.; Li, D. J.; Zeng, X. Q.</p> <p>2015-03-01</p> <p>The present study was aimed at evaluating strain-controlled cyclic deformation behavior of a rare-<span class="hlt">earth</span> (RE) element containing Mg-10Gd-3Y-0.5Zr (GW103K) alloy in different states (as-extruded, peak-aged (T5), and solution-treated and peak-aged (T6)). The addition of RE elements led to an <span class="hlt">effective</span> grain refinement and weak texture in the as-extruded alloy. While heat treatment resulted in a grain growth modestly in the T5 state and significantly in the T6 state, a high density of nano-sized and bamboo-leaf/plate-shaped β' (Mg7(Gd,Y)) precipitates was observed to distribute uniformly in the α-Mg matrix. The yield strength and ultimate tensile strength, as well as the maximum and minimum peak stresses during cyclic deformation in the T5 and T6 states were significantly higher than those in the as-extruded state. Unlike RE-free extruded Mg alloys, symmetrical hysteresis loops in tension and compression and cyclic stabilization were present in the GW103K alloy in different states. The fatigue life of this alloy in the three conditions, which could be well described by the Coffin-Manson law and Basquin's equation, was equivalent within the experimental scatter and was longer than that of RE-free extruded Mg alloys. This was predominantly attributed to the presence of the relatively weak texture and the suppression of twinning activities stemming from the fine grain sizes and especially RE-containing β' precipitates. Fatigue crack was observed to initiate from the specimen surface in all the three alloy states and the initiation site contained some cleavage-like facets after T6 heat treatment. Crack propagation was characterized mainly by the characteristic fatigue striations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950007661','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950007661"><span id="translatedtitle">The <span class="hlt">effect</span> of Low <span class="hlt">Earth</span> Orbit exposure on some experimental fluorine and silicon-containing polymers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Connell, John W.; Young, Philip R.; Kalil, Carol G.; Chang, Alice C.; Siochi, Emilie J.</p> <p>1994-01-01</p> <p>Several experimental fluorine and silicon-containing polymers in film form were exposed to low <span class="hlt">Earth</span> orbit (LEO) on a Space Shuttle flight experiment (STS-46, Evaluation of Oxygen Interaction with Materials, EOIM-3). The environmental parameters of primary concern were atomic oxygen (AO) and ultraviolet (UV) radiation. The materials were exposed to 2.3 plus or minus 0.1 x 10(exp 20) oxygen atoms/sq cm and 30.6 UV sun hours during the flight. In some cases, the samples were exposed at ambient, 120 C and 200 C. The <span class="hlt">effects</span> of exposure on these materials were assessed utilizing a variety of characterization techniques including optical, scanning electron (SEM) and scanning tunneling (STM) microscopy, UV-visible (UV-VIS) transmission, diffuse reflectance infrared (DR-FTIR), x-ray photoelectron (XPS) spectroscopy, and in a few cases, gel permeation chromatography (GPC). In addition, weight losses of the films, presumably due to AO erosion, were measured. The fluorine-containing polymers exhibited significant AO erosion and exposed films were diffuse or 'frosted' in appearance and consequently displayed dramatic reductions in optical transmission. The silicon-containing films exhibited minimum AO erosion and the optical transmission of exposed films was essentially unchanged. The silicon near the exposed surface in the films was converted to silicate/silicon oxide upon AO exposure which subsequently provided protection for the underlying material. The silicon-containing epoxies are potentially useful as AO resistant coatings and matrix resins as they are readily processed into carbon fiber reinforced composites and cured via electron radiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...585A..96T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...585A..96T"><span id="translatedtitle">Atmospheric <span class="hlt">effects</span> of stellar cosmic rays on <span class="hlt">Earth</span>-like exoplanets orbiting M-dwarfs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tabataba-Vakili, F.; Grenfell, J. L.; Grießmeier, J.-M.; Rauer, H.</p> <p>2016-01-01</p> <p>M-dwarf stars are generally considered favourable for rocky planet detection. However, such planets may be subject to extreme conditions due to possible high stellar activity. The goal of this work is to determine the potential <span class="hlt">effect</span> of stellar cosmic rays on key atmospheric species of <span class="hlt">Earth</span>-like planets orbiting in the habitable zone of M-dwarf stars and show corresponding changes in the planetary spectra. We build upon the cosmic rays model scheme of previous works, who considered cosmic ray induced NOx production, by adding further cosmic ray induced production mechanisms (e.g. for HOx) and introducing primary protons of a wider energy range (16 MeV-0.5 TeV). Previous studies suggested that planets in the habitable zone that are subject to strong flaring conditions have high atmospheric methane concentrations, while their ozone biosignature is completely destroyed. Our current study shows, however, that adding cosmic ray induced HOx production can cause a decrease in atmospheric methane abundance of up to 80%. Furthermore, the cosmic ray induced HOx molecules react with NOx to produce HNO3, which produces strong HNO3 signals in the theoretical spectra and reduces NOx-induced catalytic destruction of ozone so that more than 25% of the ozone column remains. Hence, an ozone signal remains visible in the theoretical spectrum (albeit with a weaker intensity) when incorporating the new cosmic ray induced NOx and HOx schemes, even for a constantly flaring M-star case. We also find that HNO3 levels may be high enough to be potentially detectable. Since ozone concentrations, which act as the key shield against harmful UV radiation, are affected by cosmic rays via NOx-induced catalytic destruction of ozone, the impact of stellar cosmic rays on surface UV fluxes is also studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016HyInt.237....2K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016HyInt.237....2K"><span id="translatedtitle">Mössbauer study of the <span class="hlt">effect</span> of rare <span class="hlt">earth</span> substitution into montmorillonite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuzmann, E.; Singh, L. H.; Garg, V. K.; de Oliveira, A. C.; Kovács, E. M.; Molnár, Á. M.; Homonnay, Z.; Kónya, P.; Nagy, N. M.; Kónya, J.</p> <p>2016-12-01</p> <p>Novel montmorillonites were prepared by the exchange of the interlayer cations with a series of rare <span class="hlt">earth</span> cations (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, and Er) and characterized by XRD, XRF, SEM, chemical analysis and 57Fe Mössbauer spectroscopy. An unexpected magnetically split component, assigned to iron being in the interlayer space, was observed in the Mössbauer spectra at 78K in some rare <span class="hlt">earth</span> cation exchanged montmorillonite. This paper is the initial report about this observation. The transition of iron from the octahedral site to the interlayer and possible incorporation of rare <span class="hlt">earths</span> in sites different from those which are in the interlayer space was concluded.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900004098','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900004098"><span id="translatedtitle">The <span class="hlt">effects</span> of seasonal and latitudinal <span class="hlt">earth</span> infrared radiance variations on ERBS attitude control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Phenneger, M. C.; Dehen, J.; Foch, D.; Harvie, E.; Virdy, M.</p> <p>1989-01-01</p> <p>Analysis performed in the Flight Dynamics Facility by the <span class="hlt">Earth</span> Radiation Budget Satellite (ERBS) Attitude Determination Support team illustrates the pitch attitude control motion and roll attitude errors induced by <span class="hlt">Earth</span> infrared (IR) horizon radiance variations. IR scanner and inertial reference unit (IRU) pitch and roll flight data spanning 4 years of the ERBS mission are analyzed to illustrate the changes in the magnitude of the errors on time scales of the orbital period, months, and seasons. The analysis represents a unique opportunity to compare prelaunch estimates of radiance-induced attitude errors with flight measurements. As a consequence of this work the following additional information is obtained: an assessment of an average model of these errors and its standard deviation, a measurement to determine and verify previously proposed corrections to the current <span class="hlt">Earth</span> IR radiance data base, and the possibility of a mean motion model derived from flight data in place of IRU data for ERBS fine attitude determination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016174&hterms=kinetic+body&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkinetic%2Bbody','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016174&hterms=kinetic+body&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkinetic%2Bbody"><span id="translatedtitle">On magnetodynamic <span class="hlt">effects</span> initiated by a high-speed impact of a large cosmic body upon the <span class="hlt">Earth</span>'s surface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nemchinov, I. V.; Alexandrov, P. E.; Artemiev, V. I.; Bergelson, V. I.; Rybakov, V. A.</p> <p>1993-01-01</p> <p>The impact of a large cosmic body with typical size R approximately = 1 km (mass M approximately = 4-10 Gt for a stony or icy body) moving with velocity V approximately = 50-70 km/s (kinetic energy of the order of 10 exp 21 J or 10 exp 6 Mt of TMT) on the <span class="hlt">Earth</span>'s surface leads to a full vaporization of a body and of a significant part of substance of the upper layers of the <span class="hlt">Earth</span> and even to the ionization of this vapor cloud. As a result, a hypersonic jet of air and erosion plasma is formed. The kinetic energy E sub J is far above the total energy of the geomagnetic field of the <span class="hlt">Earth</span> (approximately equivalent to the energy of 100 Mt) and the total mass of a fast-moving part of the jet M sub j approximately = 10 exp 12 kg is far above the mass of atmosphere in the jet expansion cone. Thus, the jet will propagate practically inertially with the constant mean velocity U approximately = 10-20 km/s and even higher. The interaction of this plasma jet with the <span class="hlt">Earth</span>'s magnetic field causes magnetodynamic <span class="hlt">effects</span> similar to those which are produced by cosmic nuclear explosions but of a larger scale. The preliminary results of experimental and numerical modeling of the plasma jet-magnetosphere interaction are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeCoA..74.1749M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeCoA..74.1749M"><span id="translatedtitle">Metal loading <span class="hlt">effect</span> on rare <span class="hlt">earth</span> element binding to humic acid: Experimental and modelling evidence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marsac, Rémi; Davranche, Mélanie; Gruau, Gérard; Dia, Aline</p> <p>2010-03-01</p> <p>The <span class="hlt">effect</span> of metal loading on the binding of rare <span class="hlt">earth</span> elements (REE) to humic acid (HA) was studied by combining ultrafiltration and Inductively Coupled Plasma Mass Spectrometry techniques. REE-HA complexation experiments were performed at pH 3 for REE/C molar ratios ranging from ca 4 × 10 -4 to 2.7 × 10 -2. Results show that the relative amount of REE bound to HA strongly increases with decreasing REE/C. A middle-REE (MREE) downward concavity is shown by patterns at high metal loading, whereas patterns at low metal loading display a regular increase from La to Lu. Humic Ion Model VI modelling are close to the experimental data variations, provided that (i) the ΔLK 2 parameter (i.e. the Model VI parameter taken into account the presence of strong but low density binding sites) is allowed to increase regularly from La to Lu (from 1.1 to 2.1) and (ii) the published log KMA values (i.e. the REE-HA binding constants specific to Model VI) are slightly modified, in particular with respect to heavy REE. Modelling approach provided evidence that logKdREE patterns with varying REE/C likely arises because REE binding to HA occurs through two types of binding sites in different density: (i) a few strong sites that preferentially complex the heavy REE and thus control the logKdREE atterns at low REE/C; (ii) a larger amount of weaker binding sites that preferentially complex the middle-REE and thus control the logKdREE pattern at high REE/C. Hence, metal loading exerts a major <span class="hlt">effect</span> on HA-mediated REE binding, which could explain the diversity of published conditional constants for REE binding with HA. A literature survey suggests that the few strong sites activated at low REE/C could be multidentate carboxylic sites, or perhaps N-, or P-functional groups. Finally, an examination of the literature field data proposed that the described loading <span class="hlt">effect</span> could account for much of the variation in REE patterns observed in natural organic-rich waters (DOC > 5 mg L -1 and 4 </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S33B4532O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S33B4532O"><span id="translatedtitle"><span class="hlt">Effect</span> of the <span class="hlt">Earth</span>'s surface topography on the quasi-dynamic earthquake cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohtani, M.; Hirahara, K.</p> <p>2014-12-01</p> <p>For quasi-dynamic earthquake cycle simulations (ECSs) using BIEM, we have developed a method of calculating slip response function (SRF) in a homogeneous elastic medium with an arbitrary shaped <span class="hlt">Earth</span>'s surface topography (Ohtani and Hirahara, 2013; Paper1). In this study, we report the improvement in our method. Following Hok and Fukuyama (2011), we set the <span class="hlt">Earth</span>'s surface as a free surface, in addition to the fault interface, in a homogeneous full-space medium. Then, using the analytic solution in full-space, we can calculate the <span class="hlt">Earth</span>'s surface deformation, then the SRF change. The surface cell setting determines the accuracy. For reducing the computational amount, we use the different sizes of the surface region and its divided subfault cells, depending on the fault depth. Paper1 used the uniform size for surface cells. Here, we improved our method where the <span class="hlt">Earth</span>'s surface cells closer to the trench have the finer sizes for achieving more accuracy. With such numerical SRF, we performed the quasi-dynamic ECS on a model, where the <span class="hlt">Earth</span>'s surface is convex upward. Basically, with this topography, the slip behavior approaches the full-space case, from the half-space with flat surface case. This is because the distance from the <span class="hlt">Earth</span>'s surface to the fault becomes large. When we set two asperities with negative A - B in the positive A - B background at 10km and 35km depths, the two asperities rupture independently. The recurrence time of the shallow asperity is Trshalf = 34.95, Trsflat = 34.89, and Trsactual =32.82 years, when using analytic SRF in half-space, and numerical SRF with flat surface and with actual topography, respectively. For each case, the recurrence time of the deep asperity is Tr1_dhalf = 26.80, Tr1_dflat = 26.89, and Tr1_dactual =26.69 years. Thus, the shallower asperity is more affected by the <span class="hlt">Earth</span>'s surface topography than the deeper one, because the distance change rate from the surface to the fault is larger. On the other hand, when we set</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998peea.book.....R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998peea.book.....R"><span id="translatedtitle">People and the <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rogers, John James William; Feiss, P. Geoffrey</p> <p>1998-03-01</p> <p>People and the <span class="hlt">Earth</span> examines the numerous ways in which this planet enhances and limits our lifestyles. Written with wit and remarkable insight, and illustrated with numerous case histories, it provides a balanced view of the complex environmental issues facing our civilization. The authors look at the geologic restrictions on our ability to withdraw resources--food, water, energy, and minerals--from the <span class="hlt">earth</span>, the <span class="hlt">effect</span> human activity has on the <span class="hlt">earth</span>, and the lingering damage caused by natural disasters. People and the <span class="hlt">Earth</span> examines the basic components of our interaction with this planet, provides a lucid, scientific discussion of each issue, and speculates on what the future may hold. It provides the fundamental concepts that will enable us to make wise and conscientious choices on how to live our day-to-day lives. People and the <span class="hlt">Earth</span> is an ideal introductory textbook and will also appeal to anyone concerned with our evolving relationship to the <span class="hlt">earth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16482254','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16482254"><span id="translatedtitle">SPAM-MQ-HETCOR: an improved method for heteronuclear correlation spectroscopy between <span class="hlt">quadrupolar</span> and spin-1/2 nuclei in solid-state NMR.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wiench, Jerzy W; Tricot, Gregory; Delevoye, Laurent; Trebosc, Julien; Frye, James; Montagne, Lionel; Amoureux, Jean-Paul; Pruski, Marek</p> <p>2006-01-07</p> <p>The recently introduced concept of soft pulse added mixing (SPAM) is used in two-dimensional heteronuclear correlation (HETCOR) NMR experiments between half-integer <span class="hlt">quadrupolar</span> and spin-1/2 nuclei. The experiments employ multiple quantum magic angle spinning (MQMAS) to remove the second order <span class="hlt">quadrupolar</span> broadening and cross polarization (CP) or refocused INEPT for magnetization transfer. By using previously unexploited coherence pathways, the efficiency of SPAM-MQ-HETCOR NMR is increased by a factor of almost two without additional optimization. The sensitivity gain is demonstrated on a test sample, AlPO(4)-14, using CP and INEPT to correlate (27)Al and (31)P nuclei. SPAM-3Q-HETCOR is then applied to generate (27)Al-(31)P spectra of the devitrified 41Na(2)O-20.5Al(2)O(3)-38.5P(2)O(5) glass and the silicoaluminophosphate ECR-40. Finally, the method allowed the acquisition of the first high resolution solid-state correlation spectra between (27)Al and (29)Si.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18999738','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18999738"><span id="translatedtitle">Identifying neutrino mass hierarchy at extremely small theta13 through <span class="hlt">earth</span> matter <span class="hlt">effects</span> in a supernova signal.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro</p> <p>2008-10-24</p> <p>Collective neutrino flavor transformations deep inside a supernova are sensitive to the neutrino mass hierarchy even at extremely small values of theta_(13). Exploiting this <span class="hlt">effect</span>, we show that comparison of the antineutrino signals from a galactic supernova in two megaton class water Cherenkov detectors, one of which is shadowed by <span class="hlt">Earth</span>, will enable us to distinguish between the hierarchies if sin(2)theta_(13) < or approximately 10(-5), where long baseline neutrino experiments would be ineffectual.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770017748','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770017748"><span id="translatedtitle">Investigation of the <span class="hlt">effect</span> of atmospheric dust on the determination of total ozone from the <span class="hlt">earth</span>'s ultraviolet reflectivity measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dave, J. V.</p> <p>1977-01-01</p> <p>Results are presented on the <span class="hlt">effect</span> of atmospheric aerosols on the value of total ozone, in an atmospheric column of the terrestrial atmosphere, estimated from the simulated measurements of the ultraviolet radiation back scattered by the <span class="hlt">earth</span> atmosphere models. Simulated measurements were used in five (configuration of the BUV experiment of Nimbus-4 satellite), and in six (configuration of the TOMS section of the SBUV/TOMS experiment on Nimbus-G) narrow spectral regions in the ultraviolet part of the spectrum.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880062624&hterms=Relativity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DRelativity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880062624&hterms=Relativity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DRelativity"><span id="translatedtitle"><span class="hlt">Effect</span> of general relativity on a near-<span class="hlt">Earth</span> satellite in the geocentric and barycentric reference frames</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ries, J. C.; Huang, C.; Watkins, M. M.</p> <p>1988-01-01</p> <p>Whether one uses a solar-system barycentric frame or a geocentric frame when including the general theory of relativity in orbit determinations for near-<span class="hlt">Earth</span> satellites, the results should be equivalent to some limiting accuracy. The purpose of this paper is to clarify the <span class="hlt">effects</span> of relativity in each frame and to demonstrate their equivalence through the analysis of real laser-tracking data. A correction to the conventional barycentric equations of motion is shown to be required.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=earth&id=EJ1082762','ERIC'); return false;" href="http://eric.ed.gov/?q=earth&id=EJ1082762"><span id="translatedtitle">Introducing <span class="hlt">Earth</span>'s Orbital Eccentricity</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Oostra, Benjamin</p> <p>2015-01-01</p> <p>Most students know that planetary orbits, including <span class="hlt">Earth</span>'s, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this <span class="hlt">effect</span> is somehow responsible for the seasons. In fact, the <span class="hlt">Earth</span>'s orbital eccentricity is…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060034804&hterms=earths+rotation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dearths%2Brotation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060034804&hterms=earths+rotation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dearths%2Brotation"><span id="translatedtitle">Detection and Modeling of Non-Tidal Oceanic <span class="hlt">Effects</span> on the <span class="hlt">Earth</span>'s Rotation Rate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Marcus, S. L.; Chao, Y.; Dickey, J. O.; Gegout, P.</p> <p>1998-01-01</p> <p>Sub-decadal changes in the <span class="hlt">Earth</span>'s rotation rate, and hence in the length-of-day (LOD), are largely controlled by variations in atmospheric angular momentum. Results from two oceanic general circulation models (OGCMs), forced by observed wind stress and heat flux for the years 1992-1994, show that ocean current and mass distribution changes also induce detectable LOD variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...835L...1W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...835L...1W"><span id="translatedtitle"><span class="hlt">Effects</span> of Variable Eccentricity on the Climate of an <span class="hlt">Earth</span>-like World</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Way, M. J.; Georgakarakos, Nikolaos</p> <p>2017-01-01</p> <p>The Kepler era of exoplanetary discovery has presented the astronomical community with a cornucopia of planetary systems that are very different from the one that we inhabit. It has long been known that Jupiter plays a major role in the orbital parameters of Mars and its climate, but there is also a long-standing belief that Jupiter would play a similar role for <span class="hlt">Earth</span> if not for the Moon. Using a three-dimensional general circulation model (3D GCM) with a fully coupled ocean, we simulate what would happen to the climate of an <span class="hlt">Earth</span>-like world if Mars did not exist, but a Jupiter-like planet was much closer to Earth’s orbit. We investigate two scenarios that involve the evolution of the <span class="hlt">Earth</span>-like planet’s orbital eccentricity from 0 to 0.283 over 6500 years, and from 0 to 0.066 on a timescale of 4500 years. In both cases we discover that they would maintain relatively temperate climates over the timescales simulated. More <span class="hlt">Earth</span>-like planets in multi-planet systems will be discovered as we continue to survey the skies and the results herein show that the proximity of large gas giant planets may play an important role in the habitability of these worlds. These are the first such 3D GCM simulations using a fully coupled ocean with a planetary orbit that evolves over time due to the presence of a giant planet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24897184','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24897184"><span id="translatedtitle"><span class="hlt">Effect</span> of <span class="hlt">earth</span> as an additional stimulus on the behaviour of confined piglets.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Appleby, M C; Wood-Gush, D G</p> <p>1988-08-01</p> <p>Groups of 8 piglets were housed in flat-deck cages with slatted floors. Experimental cages were provided with a trough of sterilized <span class="hlt">earth</span>, and the behaviour of focal individuals was recorded for comparison with controls. This replaced an earlier study, with which some of the results were combined. Records were analysed for frequencies and duration of certain activities, and first order sequence analysis was carried out. Experimental piglets rooted in <span class="hlt">earth</span> for 4 to 8% of observations and also fed for longer. They spent less time sitting or lying. Aggression was reduced and there was a trend for experimental piglets to chew each other less. These differences suggested conditions were more favourable in experimental pens than control pens. However, there were few differences in first order behavioural transitions. Use of <span class="hlt">earth</span> was not involved in sequences with activities such as feeding, drinking or lying as expected. It seems likely that in these circumstances <span class="hlt">earth</span> did not act as a stimulus relevant to behavioural organization, but in some other way, with interest declining over time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740021591','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740021591"><span id="translatedtitle"><span class="hlt">Effects</span> of atmospheric aerosols on scattering reflected visible light from <span class="hlt">earth</span> resource features</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Noll, K. E.; Tschantz, B. A.; Davis, W. T.</p> <p>1972-01-01</p> <p>The vertical variations in atmospheric light attenuation under ambient conditions were identified, and a method through which aerial photographs of <span class="hlt">earth</span> features might be corrected to yield quantitative information about the actual features was provided. A theoretical equation was developed based on the Bouguer-Lambert extinction law and basic photographic theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=earth+AND+hour&id=EJ853219','ERIC'); return false;" href="http://eric.ed.gov/?q=earth+AND+hour&id=EJ853219"><span id="translatedtitle">An <span class="hlt">Effect</span> of Technology Based Inquiry Approach on the Learning of "<span class="hlt">Earth</span>, Sun, & Moon" Subject</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Turkmen, Hakan</p> <p>2009-01-01</p> <p>The purpose of this study was to investigate what affect a technology based inquiry approach (TBIA) had on 5th grade primary students' understanding of <span class="hlt">earth</span>, sun, and moon concept in a science and technology course and how this changed their academic achievements. This study was carried out in a 5th grade elementary science and technology course…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ESDD....1..191D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ESDD....1..191D"><span id="translatedtitle">Assessing life's <span class="hlt">effects</span> on the interior dynamics of planet <span class="hlt">Earth</span> using non-equilibrium thermodynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dyke, J. G.; Gans, F.; Kleidon, A.</p> <p>2010-09-01</p> <p>Vernadsky described life as the geologic force, while Lovelock noted the role of life in driving the <span class="hlt">Earth</span>'s atmospheric composition to a unique state of thermodynamic disequilibrium. Here, we use these notions in conjunction with thermodynamics to quantify biotic activity as a driving force for geologic processes. Specifically, we explore the hypothesis that biologically-mediated processes operating on the surface of the <span class="hlt">Earth</span>, such as the biotic enhancement of weathering of continental crust, affect interior processes such as mantle convection and have therefore shaped the evolution of the whole <span class="hlt">Earth</span> system beyond its surface and atmosphere. We set up three simple models of mantle convection, oceanic crust recycling and continental crust recycling. We describe these models in terms of non-equilibrium thermodynamics in which the generation and dissipation of gradients is central to driving their dynamics and that such dynamics can be affected by their boundary conditions. We use these models to quantify the maximum power that is involved in these processes. The assumption that these processes, given a set of boundary conditions, operate at maximum levels of generation and dissipation of free energy lead to reasonable predictions of core temperature, seafloor spreading rates, and continental crust thickness. With a set of sensitivity simulations we then show how these models interact through the boundary conditions at the mantle-crust and oceanic-continental crust interfaces. These simulations hence support our hypothesis that the depletion of continental crust at the land surface can affect rates of oceanic crust recycling and mantle convection deep within the <span class="hlt">Earth</span>'s interior. We situate this hypothesis within a broader assessment of surface-interior interactions by setting up a work budget of the <span class="hlt">Earth</span>'s interior to compare the maximum power estimates that drive interior processes to the power that is associated with biotic activity. We estimate that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ975551.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ975551.pdf"><span id="translatedtitle">The <span class="hlt">Effect</span> of the Conceptual Change Oriented Instruction through Cooperative Learning on 4th Grade Students' Understanding of <span class="hlt">Earth</span> and Sky Concepts</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Celikten, Oksan; Ipekcioglu, Sevgi; Ertepinar, Hamide; Geban, Omer</p> <p>2012-01-01</p> <p>The purpose of this study was to compare the <span class="hlt">effectiveness</span> of the conceptual change oriented instruction through cooperative learning (CCICL) and traditional science instruction (TI) on 4th grade students' understanding of <span class="hlt">earth</span> and sky concepts and their attitudes toward <span class="hlt">earth</span> and sky concepts. In this study, 56 fourth grade students from the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MsT.........14B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MsT.........14B"><span id="translatedtitle">Determining the Polar Cosmic Ray <span class="hlt">Effect</span> on Cloud Microphysics and the <span class="hlt">Earth</span>'s Ozone Layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beckie, Charlene Radons</p> <p></p> <p>Earth’s changing climate is an important topic where atmospheric ozone plays a critical role. Ozone has a direct influence on the amount and type of solar radiation received by the <span class="hlt">Earth</span>. This study addresses how cosmic rays may influence the ozone layer by ionizing Earth’s atmosphere and enhancing the growth of cloud condensation nuclei and rate of chemical reactions on polar ice cloud surfaces. This theory was largely based on the lifetime work by Lu [2010]. The region of interest was centered over the Thule, Greenland neutron monitor station. Using cosmic ray, satellite-based ISCCP and ICARE project cloud data along with TOMS-OMI-SBUV and TEMIS total column ozone data, data comparisons were done. Plots of cosmic rays versus Antarctic atmospheric ozone from Lu [2009] were reproduced using regional Arctic data and extended to include years from 1983 to 2011. Comparisons to the research by Harris et al. [2010] were made by substituting ice cloud optical thickness for the cloud parameter and seasonal total column ozone for winter stratospheric ozone loss. The results of these data evaluations showed that the regional Arctic view matched very closely to Lu’s work from the Antarctic. The ozone 3-point moving average case demonstrated a statistically significant correlation of -0.508. Extending the data duration exposed a cosmic ray data peak that was 14 percent larger than the two previous 11-year cycles. Ice cloud tau / ozone data comparisons did not produce the strong correlations from Harris et al. [2010]. Five years of low stratospheric temperatures and increased volumes of polar stratospheric clouds, identified by Rex et al. [2006], matched significant years of total column ozone minimums. Polar atmospheric CO2 trended along with ice cloud tau and oppositely to total column ozone, suggesting that lower stratospheric temperatures are instrumental in ozone reduction. Future work would involve using more extensive datasets, focusing on parameters such as ice</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSM33A1750S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSM33A1750S"><span id="translatedtitle"><span class="hlt">Effect</span> of EMIC Waves on the Lifetime of Energetic Electrons in the <span class="hlt">Earth</span>'s Inner Radiation Belt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shao, X.; Papadopoulos, K.; Sharma, A. S.; Demekhov, A.</p> <p>2008-12-01</p> <p>The stably trapped electrons in the inner radiation belt have lifetimes of years and energies higher than a few hundred keV. These energetic electrons can have serious <span class="hlt">effects</span> on the way spacecrafts and satellites operate and cause significant hazards to low <span class="hlt">Earth</span> orbit (LEO) satellites. For mitigating these hazards it is necessary to investigate ways for reducing the electron life times, for example, through pitch angle scattering by waves. For these waves, the gyro-resoance condition yields the minimum wavelength requirement for given particle energy and local magnetic field. For example, at the magnetic equator at L = 2 the waves resonant with 1 MeV electrons should have wavelengths less than 10 km. Low frequency Electromagnetic Ion-Cyclotron (EMIC) waves occur in three bands with frequencies below the hydrogen, helium, and oxygen ion gyro-frequencies, respectively. At frequencies close to the ion gyro-frequencies, the EMIC waves can have wavelength short enough to gyro-resonate with energetic electrons, which can lead to significant changes in the lifetimes of electrons in the inner ration belt. However at these altitudes the amplitudes of naturally excited EMIC waves do not yield significant scattering of the energetic electrons and artificial sources are needed. In order to define the characteristics of such sources we investigated the lifetime of inner belt energetic electrons subject to pitch angle scattering with EMIC waves. The resonant wave characteristics are obtained using the global core plasma model (GCPM). The lifetimes of the electrons in the presence of these waves are computed using the pitch angle diffusion coefficient for broadband waves. For several hundred Watts of broadband EMIC waves in the shell volume enclosed by magnetic field lines at L = 2.0 with width dL = 0.1, the lifetime of 1 MeV electrons can be reduced to a few months. This is a considerable reduction compared to the average life times of about years and have important</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P11B1826A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P11B1826A"><span id="translatedtitle">Uderstanding Snowball <span class="hlt">Earth</span> Deglaciation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abbot, D. S.</p> <p>2012-12-01</p> <p><span class="hlt">Earth</span>, a normally clement planet comfortably in its star's habitable zone, suffered global or nearly global glaciation at least twice during the Neoproterozoic era (at about 635 and 710 million years ago). Viewed in the context of planetary evolution, these pan-global glaciations (Snowball <span class="hlt">Earth</span> events) were extremely rapid, lasting only a few million years. The dramatic <span class="hlt">effect</span> of the Snowball <span class="hlt">Earth</span> events on the development of the planet can be seen through their link to rises in atmospheric oxygen and evolutionary innovations. These potential catastrophes on an otherwise clement planet can be used to gain insight into planetary habitability more generally. Since <span class="hlt">Earth</span> is not currently a Snowball, a sound deglaciation mechanism is crucial for the viability of the Snowball <span class="hlt">Earth</span> hypothesis. The traditional deglaciation mechanism is a massive build up of CO2 due to reduced weathering during Snowball <span class="hlt">Earth</span> events until tropical surface temperatures reach the melting point. Once initiated, such a deglaciation might happen on a timescale of only dozens of thousands of years and would thrust <span class="hlt">Earth</span> from the coldest climate in its history to the warmest. Therefore embedded in Snowball <span class="hlt">Earth</span> events is an even more rapid and dramatic environmental change. Early global climate model simulations raised doubt about whether Snowball <span class="hlt">Earth</span> deglaciation could be achieved at a CO2 concentration low enough to be consistent with geochemical data, which represented a potential challenge to the Snowball <span class="hlt">Earth</span> hypothesis. Over the past few years dust and clouds have emerged as the essential missing additional processes that would allow Snowball <span class="hlt">Earth</span> deglaciation at a low enough CO2 concentration. I will discuss the dust and cloud mechanisms and the modeling behind these ideas. This effort is critical for the broader implications of Snowball <span class="hlt">Earth</span> events because understanding the specific deglaciation mechanism determines whether similar processes could happen on other planets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V33A1162D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V33A1162D"><span id="translatedtitle">Sulfur <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Jong, B. H.</p> <p>2007-12-01</p> <p>Variations in surface tension affect the buoyancy of objects floating in a liquid. Thus an object floating in water will sink deeper in the presence of dishwater fluid. This is a very minor but measurable <span class="hlt">effect</span>. It causes for instance ducks to drown in aqueous solutions with added surfactant. The surface tension of liquid iron is very strongly affected by the presence of sulfur which acts as a surfactant in this system varying between 1.9 and 0.4 N/m at 10 mass percent Sulfur (Lee & Morita (2002), This last value is inferred to be the maximum value for Sulfur inferred to be present in the liquid outer core. Venting of Sulfur from the liquid core manifests itself on the <span class="hlt">Earth</span> surface by the 105 to 106 ton of sulfur vented into the atmosphere annually (Wedepohl, 1984). Inspection of surface Sulfur emission indicates that venting is non-homogeneously distributed over the <span class="hlt">Earth</span>'s surface. The implication of such large variation in surface tension in the liquid outer core are that at locally low Sulfur concentration, the liquid outer core does not wet the predominantly MgSiO3 matrix with which it is in contact. However at a local high in Sulfur, the liquid outer core wets this matrix which in the fluid state has a surface tension of 0.4 N/m (Bansal & Doremus, 1986), couples with it, and causes it to sink. This differential and diapiric movement is transmitted through the essentially brittle mantle (1024 Pa.s, Lambeck & Johnson, 1998; the maximum value for ice being about 1030 Pa.s at 0 K, in all likely hood representing an upper bound of viscosity for all materials) and manifests itself on the surface by the roughly 20 km differentiation, about 0.1 % of the total mantle thickness, between topographical heights and lows with concomitant lateral movement in the crust and upper mantle resulting in thin skin tectonics. The brittle nature of the medium though which this movement is transmitted suggests that the extremes in topography of the D" layer are similar in range to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28359999','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28359999"><span id="translatedtitle">Potency of (doped) rare <span class="hlt">earth</span> oxide particles and their constituent metals to inhibit algal growth and induce direct toxic <span class="hlt">effects</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Joonas, Elise; Aruoja, Villem; Olli, Kalle; Syvertsen-Wiig, Guttorm; Vija, Heiki; Kahru, Anne</p> <p>2017-03-27</p> <p>Use of rare <span class="hlt">earth</span> elements (REEs) has increased rapidly in recent decades due to technological advances. It has been accompanied by recurring rare <span class="hlt">earth</span> element anomalies in water bodies. In this work we (i) studied the <span class="hlt">effects</span> of eight novel doped and one non-doped rare <span class="hlt">earth</span> oxide (REO) particles (aimed to be used in solid oxide fuel cells and gas separation membranes) on algae, (ii) quantified the individual adverse <span class="hlt">effects</span> of the elements that constitute the (doped) REO particles and (iii) attempted to find a discernible pattern to relate REO particle physicochemical characteristics to algal growth inhibitory properties. Green algae Raphidocelis subcapitata (formerly Pseudokirchneriella subcapitata) were used as a test species in two different formats: a standard OECD201 algal growth inhibition assay and the algal viability assay (a 'spot test') that avoids nutrient removal <span class="hlt">effects</span>. In the 24h 'spot' test that demonstrated direct toxicity, algae were not viable at REE concentrations above 1mgmetal/L. 72-hour algal growth inhibition EC50 values for four REE salts (Ce, Gd, La, Pr) were between 1.2 and 1.4mg/L, whereas the EC50 for REO particles ranged from 1 to 98mg/L. The growth inhibition of REEs was presumably the result of nutrient sequestration from the algal growth medium. The adverse <span class="hlt">effects</span> of REO particles were at least in part due to the entrapment of algae within particle agglomerates. Adverse <span class="hlt">effects</span> due to the dissolution of constituent elements from (doped) REO particles and the size or specific surface area of particles were excluded, except for La2NiO4. However, the structure of the particles and/or the varying <span class="hlt">effects</span> of oxide composition might have played a role in the observed <span class="hlt">effects</span>. As the production rates of these REO particles are negligible compared to other forms of REEs, there is presumably no acute risk for aquatic unicellular algae.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800060842&hterms=calculation+infinitesimal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcalculation%2Binfinitesimal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800060842&hterms=calculation+infinitesimal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcalculation%2Binfinitesimal"><span id="translatedtitle">The <span class="hlt">effect</span> of <span class="hlt">earth</span>'s atmosphere on contrast reduction for a nonuniform surface albedo and 'two-halves' field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mekler, Y.; Kaufman, Y. J.</p> <p>1980-01-01</p> <p>The paper presents a model for contrast reduction by atmospheric haze developed for the 'two-halves' field of the <span class="hlt">earth</span>'s surface and other geometries of the <span class="hlt">earth</span>'s surface albedo. The model is based on a simplified solution of the equation of radiative transfer in two dimensions, resulting in a method for calculation of the upward zenith intensity in the atmosphere as a function of the distance from the border between the two half planes, for an unabsorbing atmosphere. The adjacency <span class="hlt">effect</span> between two infinitesimal areas of different albedos is calculated; the resultant simplified solution is used to develop expressions for the line-spread function of the atmosphere and the modulation transfer function. The line-spread function is used to calculate the point spread function, which can be used to compute the intensity above any surface with given spatial dependence of the reflectivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcAau.129..389S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcAau.129..389S"><span id="translatedtitle">The <span class="hlt">effects</span> of oblateness and solar radiation pressure on halo orbits in the photogravitational Sun-<span class="hlt">Earth</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srivastava, Vineet K.; Kumar, Jai; Kushvah, Badam Singh</p> <p>2016-12-01</p> <p>In this paper, we construct a third-order analytic approximate solution using the Lindstedt-Poincare method in the photogravitational circular restricted three body problem considering the Sun as a radiating source and the <span class="hlt">Earth</span> as an oblate spheroid for computing halo orbits around the collinear Lagrangian points L1 and L2. Further, the well-known differential correction and continuation schemes are used to compute halo orbits and their families numerically. The <span class="hlt">effects</span> of solar radiation pressure and oblateness on the orbit are studied around both Lagrangian points. From the study, it is noticed that time period of the halo orbit increases around L1 and L2 accounting oblateness of the <span class="hlt">Earth</span> and solar radiation pressure of the Sun. It is also found that stability of halo orbits is a weak function of the out-of-plane amplitude and mass reduction factor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830042038&hterms=history+water+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhistory%2Bwater%2Bearth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830042038&hterms=history+water+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhistory%2Bwater%2Bearth"><span id="translatedtitle"><span class="hlt">Effects</span> of increased CO2 concentrations on surface temperature of the early <span class="hlt">earth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kuhn, W. R.; Kasting, J. F.</p> <p>1983-01-01</p> <p>It is pointed out that enhanced levels of CO2 in the atmosphere could have provided the necessary warming to maintain the temperature above freezing. The processes that have been proposed for these larger amounts of CO2 are increased tectonic activity, a decrease in the solubility of CO2 in the oceans, rock weathering, and sediment deposition. It is shown here that large CO2 concentrations are necessary to maintain the early <span class="hlt">earth</span>'s surface temperature at approximately today's level. A thousand times the present atmospheric level of CO2 in the atmosphere would yield a temperature of 292 K, whereas a 100-fold increase in CO2 concentration would give a temperature of 284 K. The surface warming is highly dependent on the amount of water vapor and clouds, and knowledge of both of these during the early history of the <span class="hlt">earth</span> is scant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7323E..0IP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7323E..0IP"><span id="translatedtitle"><span class="hlt">Effects</span> of lidar point density on bare <span class="hlt">earth</span> extraction and DEM creation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Puetz, Angela M.; Olsen, R. Chris; Anderson, Brian</p> <p>2009-05-01</p> <p>Data density has a crucial impact on the accuracy of Digital Elevation Models (DEMs). In this study, DEMs were created from a high point-density LIDAR dataset using the bare <span class="hlt">earth</span> extraction module in Quick Terrain Modeler. Lower point-density LIDAR collects were simulated by randomly selecting points from the original dataset at a series of decreasing percentages. The DEMs created from the lower resolution datasets are compared to the original DEM. Results show a decrease in DEM accuracy as the resolution of the LIDAR dataset is reduced. Some analysis is made of the types of errors encountered in the lower resolution DEMs. It is also noted that the percentage of points classified as bare <span class="hlt">earth</span> decreases as the resolution of the LIDAR dataset is reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22410059','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22410059"><span id="translatedtitle"><span class="hlt">Effect</span> of spacer layer on the magnetization dynamics of permalloy/rare-<span class="hlt">earth</span>/permalloy trilayers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Luo, Chen Yin, Yuli; Zhang, Dong; Jiang, Sheng; Yue, Jinjin; Zhai, Ya; Du, Jun; Zhai, Hongru</p> <p>2015-05-07</p> <p>The permalloy/rare-<span class="hlt">earth</span>/permalloy trilayers with different types (Gd and Nd) and thicknesses of spacer layer are investigated using frequency dependence of ferromagnetic resonance (FMR) measurements at room temperature, which shows different behaviors with different rare <span class="hlt">earth</span> spacer layers. By fitting the frequency dependence of the FMR resonance field and linewidth, we find that the in-plane uniaxial anisotropy retains its value for all samples, the perpendicular anisotropy remains almost unchanged for different thickness of Gd layer but the values are tailored by different thicknesses of Nd layer. The Gilbert damping is almost unchanged with different thicknesses of Gd; however, the Gilbert damping is significantly enhanced from 8.4×10{sup −3} to 20.1×10{sup −3} with 6 nm of Nd and then flatten out when the Nd thickness rises above 6 nm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70042407','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70042407"><span id="translatedtitle">The <span class="hlt">effect</span> of error in theoretical <span class="hlt">Earth</span> tide on calibration of borehole strainmeters</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Langbein, John</p> <p>2010-01-01</p> <p>Since the installation of borehole strainmeters into the ground locally distorts the strain in the rock, these strainmeters require calibration from a known source which typically is the <span class="hlt">Earth</span> tide. Consequently, the accuracy of the observed strain changes from borehole strainmeters depends upon the calibration derived from modeling the <span class="hlt">Earth</span> tide. Previous work from the mid-1970s, which is replicated here, demonstrate that the theoretical tide can differ by 30% from the tide observed at surface-mounted, long-baseline strainmeters. In spite of possible inaccurate tidal models, many of the 74 borehole strainmeters installed since 2005 can be “calibrated”. However, inaccurate tidal models affect the amplitude and phase of observed transient strain changes which needs to be considered along with the precision of the data from the inherent drift of these borehole instruments. In particular, the error from inaccurate tidal model dominates the error budget in the observation of impulsive, sub-daily, strain-transients.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25285437','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25285437"><span id="translatedtitle">NIR persistent luminescence of lanthanide ion-doped rare-<span class="hlt">earth</span> oxycarbonates: the <span class="hlt">effect</span> of dopants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Caratto, Valentina; Locardi, Federico; Costa, Giorgio Andrea; Masini, Roberto; Fasoli, Mauro; Panzeri, Laura; Martini, Marco; Bottinelli, Emanuela; Gianotti, Enrica; Miletto, Ivana</p> <p>2014-10-22</p> <p>A series of luminescent rare-<span class="hlt">earth</span> ion-doped hexagonal II-type Gd oxycarbonate phosphors Gd2-xRExO2CO3 (RE = Eu(3+), Yb(3+), Dy(3+)) have been successfully synthesized by thermal decomposition of the corresponding mixed oxalates. The Yb(3+) doped Gd-oxycarbonate has evidenced a high persistent luminescence in the NIR region, that is independent from the temperature and makes this materials particular attractive as optical probes for bioimaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA103897','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA103897"><span id="translatedtitle">Cosmic Ray <span class="hlt">Effects</span> on Microelectronics. Part 1. The Near-<span class="hlt">Earth</span> Particle Environment</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>1981-08-25</p> <p>common in nature and abundant in space, This report describes the natural particle environment in which modern space-borne electronics must operate, and...provides a simple but accurate empirical model of that environment . DD ’,0N7 1473 ECITION 01 IIQ ISy IS CESOLISE SIN 0102-014-41150 SECURITY...Importance of the Various Components in the Near-<span class="hlt">Earth</span> Particle Environment ......................................... 68 8.0 Conclusions and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990042412','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990042412"><span id="translatedtitle">Compensation for Spherical Geometric and Absorption <span class="hlt">Effects</span> on Lower Thermospheric Emission Intensities Derived from High <span class="hlt">Earth</span> Orbit Images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Swift, W.; Germany, G. A.; Richards, P. G.; Parks, G. K.; Brittnacher, M.; Spann, J. F., Jr.</p> <p>1997-01-01</p> <p>Remote sensing of the atmosphere from high <span class="hlt">earth</span> orbit is very attractive due to the large field of view obtained and a true global perspective. This viewpoint is complicated by <span class="hlt">earth</span> curvature <span class="hlt">effects</span> so that slant path enhancement and absorption <span class="hlt">effects</span>, small from low <span class="hlt">earth</span> orbit, become dominant even at small nadir view angles. The <span class="hlt">effect</span> is further complicated by the large range of local times and solar zenith angles in a single image leading to a modulation of the image intensity by a significant portion of the diurnal height variation of the absorbing layer. The latter <span class="hlt">effect</span> is significant in particular for mesospheric, stratospheric and auroral emissions due to their depth in the atmosphere. As a particular case, the emissions from atomic oxygen (130.4 and 135.6 nm) and molecular nitrogen (two LBH bands, LBHS from 140 to 160 nm and LBHL from 160 to 180 nm) as viewed from the Ultraviolet Imager (UVI) are examined. The LBH emissions are of particular interest since LBHS has significant 02 absorption while LBHL does not, In the case of auroral emissions this differential absorption, well examined in the nadir, gives information about the height of the emission and therefore the energy of the precipitating particles. Using simulations of the viewing geometry and images from the UVI we examine these <span class="hlt">effects</span> and obtain correction factors to adjust to the nadir case with a significant improvement of the derived characteristic energy. There is a surprisingly large <span class="hlt">effect</span> on the images from the 02 diurnal layer height changes. An empirical compensation to the nadir case is explored based on the local nadir and local zenith angles for each portion of the image. These compensations are demonstrated as applied to the above emissions in both auroral and dayglow images and compared to models. The extension of these findings to other instruments, emissions and spectral regions is examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JAP...111k2631G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JAP...111k2631G"><span id="translatedtitle"><span class="hlt">Effect</span> of rare <span class="hlt">earth</span> substitution in the density of electronic states of LnOFeAs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García Saravia Ortíz de Montellano, A.; Mustre de León, J.; Saini, N. L.; Bianconi, A.</p> <p>2012-06-01</p> <p>Measurements of the Fe K-edge x-ray absorption near edge (XANES) spectra of LnOFeAs (Ln being a lanthanide) high Tc superconductors exhibit significant changes in the pre-edge peak region upon rare <span class="hlt">earth</span> substitution. Ab initio XANES calculations, based on the local structure centered at the Fe site obtained by crystallographic investigations, reproduce the observed changes in the spectra, indicating variations of the Fe d-local unoccupied electronic states. The calculated Fe density of states (DOS) at the Fermi energy shows an increase of the Fe d-density of states with increasing height of the arsenic atomic position with respect to the iron plane, similar to that observed for the superconducting transition temperature, Tc. These calculations show that not only the atomic position variation of the Fe-As layers induced by the rare <span class="hlt">earth</span> substitution is relevant in the increase of the DOS at the Fermi-level, but the actual change in electronic configuration of the rare <span class="hlt">earth</span> also plays a role in the increase of Fe d-density of states at the Fermi energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SGeo...37..757S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SGeo...37..757S"><span id="translatedtitle"><span class="hlt">Effects</span> of Energetic Solar Emissions on the <span class="hlt">Earth</span>-Ionosphere Cavity of Schumann Resonances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sátori, Gabriella; Williams, Earle; Price, Colin; Boldi, Robert; Koloskov, Alexander; Yampolski, Yuri; Guha, Anirban; Barta, Veronika</p> <p>2016-07-01</p> <p>Schumann resonances (SR) are the electromagnetic oscillations of the spherical cavity bounded by the electrically conductive <span class="hlt">Earth</span> and the conductive but dissipative lower ionosphere (Schumann in Z Naturforsch A 7:6627-6628, 1952). Energetic emissions from the Sun can exert a varied influence on the various parameters of the <span class="hlt">Earth</span>'s SR: modal frequencies, amplitudes and dissipation parameters. The SR response at multiple receiving stations is considered for two extraordinary solar events from Solar Cycle 23: the Bastille Day event (July 14, 2000) and the Halloween event (October/November 2003). Distinct differences are noted in the ionospheric depths of penetration for X-radiation and solar protons with correspondingly distinct signs of the frequency response. The preferential impact of the protons in the magnetically unshielded polar regions leads to a marked anisotropic frequency response in the two magnetic field components. The general immunity of SR amplitudes to these extreme external perturbations serves to remind us that the amplitude parameter is largely controlled by lightning activity within the <span class="hlt">Earth</span>-ionosphere cavity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED386172.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED386172.pdf"><span id="translatedtitle">Rainbow <span class="hlt">Earth</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Arizona State Dept. of Library and Archives, Phoenix.</p> <p></p> <p>The environment is a great concern in the 1990s, and everyone needs to work at maintaining our planet. The 1992 Arizona State Library Reading Program, "Rainbow <span class="hlt">Earth</span>," provides children with many techniques they can use to help the <span class="hlt">Earth</span>. This reading program guide provides information on the following: goals, objectives, and evaluation;…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.4295B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.4295B"><span id="translatedtitle">A proof of the cancellation of the redistribution tidal potential <span class="hlt">effects</span> on the rotation of an elastic <span class="hlt">Earth</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baenas, Tomás; Escapa, Alberto; Ferrándiz, Jose Manuel</p> <p>2014-05-01</p> <p>The gravitational action of the Moon and the Sun on the elastic <span class="hlt">Earth</span> originates a redistribution of its mass. In turn, this redistribution is responsible of an additional term in the gravitational potential energy of the system, commonly referred to as tidal potential of redistribution. Its <span class="hlt">effects</span> on the <span class="hlt">Earth</span> rotation were previously discussed in Escapa et al. (2004) and Lambert & Mathews (2006). A numerical approach was followed in those works to show that for an elastic <span class="hlt">Earth</span> model, assumed to be spherical and non-rotating in the undeformed state, there is no net contribution to the motion of the figure axis. This result is consistent with the corresponding one deduced from the torque approach, where one can derive analytically that the redistribution torque for that elastic <span class="hlt">Earth</span> model vanishes (e.g., Krasinsky 1999). However, it is far from being a trivial question to recover the same result when working directly with the tidal potential of redistribution, as in Escapa et al. (2004) or Lambert & Mathews (2006). In this investigation we revisit the issue, enhancing and completing former results by Escapa et al. (2004). In particular, we aim at proving, by analytical means, that the redistribution tidal potential of the former elastic <span class="hlt">Earth</span> model does not affect its rotational motion. To this end we expand that potential in terms of an Andoyer-like set of canonical variables, and then compute the torque associated to it. This choice was motivated by the suitability of this set of variables to extend our calculations to the nutations of other different elastic or anelastic <span class="hlt">Earth</span> models, through the Hamiltonian framework (e.g., Ferrándiz et al. 2012). We show the exact cancellation of the derived expressions as a consequence of certain properties fulfilled by the expansions of the orbital motion of the perturbing bodies. Acknowledgement. - This work has been partially supported by the Spanish government trhough the MINECO projects I+D+I AYA201022039-C02-01, AYA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890011994','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890011994"><span id="translatedtitle">Environmental <span class="hlt">effects</span> of large impacts on the <span class="hlt">earth</span>; relation to extinction mechanisms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Okeefe, John D.; Ahrens, Thomas J.; Koschny, Detlef</p> <p>1988-01-01</p> <p>Since Alvarez et al., discovered a worldwide approx. cm-thick layer of fine sediments laden with platinum group elements in approximately chondritic proportions exactly at the Cretaceous-Tertiary (C-T) boundary, and proposed bolide-impact as triggering mass extinctions, many have studied this hypothesis and the layer itself with its associated spherules and shocked quartz. At issue is whether the mass extinctions, and this horizon has an impact versus volcanic origin. A critical feature of the Alvarez hypothesis is the suggestion that the bolide or possibly a shower of objects delivered to the <span class="hlt">earth</span> approx. 0.6 x 10 to the 18th power g of material which resulted in aerosol-sized ejecta such that global insolation was drastically reduced for significant periods. Such an event would lower temperatures on continents and halt photosynthesis in the upper 200 m of th eocean. The latter would strangle the marine food chain and thus produce the major marine faunal extinctions which mark the C-T boundary. Crucial issues examined include: What are the dynamics of atmospheric flow occurring upon impact of a large bolide with the <span class="hlt">earth</span>; What is the size distributions of the very fine impact ejecta and how do these compare to the models of ejecta which are used to model the <span class="hlt">earth</span>'s radiative thermal balance. The flow field due to passage of a 10 km diameter bolide through an exponential atmosphere and the interaction of the gas flow and bolide with the solid ear was calculated. The CO2 released upon impact onto shallow marine carbonate sections was modeled and found that the mass of CO2 released exceeds the present 10 to the 18th power g CO2 budget of the <span class="hlt">earth</span>'s atmosphere by several times. Using the calculations of Kasting and Toon it was found that to compute the temperature rise of the <span class="hlt">earth</span>'s surface as a function of CO2 content, it was found that sudden and prolonged global increases are induced from impact of 20 to 50 km radius projectiles and propose that sudden</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070022793','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070022793"><span id="translatedtitle"><span class="hlt">Effects</span> of RAM Exposure on a Low <span class="hlt">Earth</span> Orbit BroadBand Radiometer (BBR): CERES Experience and Implications for <span class="hlt">Earth</span>CARE</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matthews, Grant; Priestley, Kory; Thomas, Susan; Hess, Pil; Cooper, Denise; Walikainen, Dale</p> <p>2007-01-01</p> <p>In order to best detect real changes in the <span class="hlt">Earth</span>'s climate system it is estimated that space based instrumentation measuring the global <span class="hlt">Earth</span> Radiation Budget (ERB) must remain calibrated with a stability of 0.3% per decade. This level of stability is beyond the specified accuracy of existing ERB programs such as the Clouds and the <span class="hlt">Earth</span>'s Radiant Energy System (CERES, using three broadband radiometric scanning channels: the shortwave (SW 0.3 - 5?m), total (0.3 - >100 micron), and window (8 - 12 micron)). When in low <span class="hlt">earth</span> orbit, it has been shown that optical response to blue-UV radiance can be reduced significantly (> 3%) due to UV hardened contaminants deposited on the surface of the optics. Evidence suggests that exposure of telescope optics to the forward looking ram direction is the primary cause of this contamination build up. With typical onboard calibration lamps emitting very low energy in the blue-UV region, this darkening is not directly measurable using standard internal calibration techniques. This paper describes a study using a model of ram exposure induced contaminant deposition and darkening, in conjunction standard established in-flight vicarious and internal calibration techniques to derive the spectral shape of the darkening to which a broadband instrument is subjected. The results of the model when applied to the CERES instruments are shown. These findings are of great importance to the <span class="hlt">Earth</span>CARE project, whose BBR uses one broadband telescope permanently looking forward at 45 degrees, with continual exposure to the ram direction. Specific attention may therefore be needed in the design of BBR optics and on-board calibration in order to prevent or compensate for the spectral darkening seen in the CERES project.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20130005710&hterms=history+climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhistory%2Bclimate%2Bchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20130005710&hterms=history+climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhistory%2Bclimate%2Bchange"><span id="translatedtitle">The <span class="hlt">Effects</span> of Solar Variability on <span class="hlt">Earth</span>'s Climate: A Workshop Report</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2012-01-01</p> <p>Solar irradiance, the flux of the Sun s output directed toward <span class="hlt">Earth</span>, is <span class="hlt">Earth</span> s main energy source.1 The Sun itself varies on several timescales over billions of years its luminosity increases as it evolves on the main sequence toward becoming a red giant; about every 11 years its sunspot activity cycles; and within just minutes flares can erupt and release massive amounts of energy. Most of the fluctuations from tens to thousands of years are associated with changes in the solar magnetic field. The focus of the National Research Council's September 2011 workshop on solar variability and <span class="hlt">Earth</span>'s climate, and of this summary report, is mainly magnetically driven variability and its possible connection with <span class="hlt">Earth</span>'s climate variations in the past 10,000 years. Even small variations in the amount or distribution of energy received at <span class="hlt">Earth</span> can have a major influence on <span class="hlt">Earth</span>'s climate when they persist for decades. However, no satellite measurements have indicated that solar output and variability have contributed in a significant way to the increase in global mean temperature in the last 50 years. Locally, however, correlations between solar activity and variations in average weather may stand out beyond the global trend; such has been argued to be the case for the El Nino-Southern Oscillation, even in the present day. A key area of inquiry deals with establishing a unified record of the solar output and solar-modified particles that extends from the present to the prescientific past. The workshop focused attention on the need for a better understanding of the links between indices of solar activity such as cosmogenic isotopes and solar irradiance. A number of presentations focused on the timescale of the solar cycle and of the satellite record, and on the problem of extending this record back in time. Highlights included a report of progress on pyroheliometer calibration, leading to greater confidence in the time history and future stability of total solar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MMI....19..347K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MMI....19..347K"><span id="translatedtitle">Rare <span class="hlt">earth</span> dependent formation of PbF2 nanocrystals and its <span class="hlt">effect</span> on the emission properties in oxyfluoride glasses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Kyoung Hoon; Choi, Yong Gyu; Im, Won Bin; Chung, Woon Jin</p> <p>2013-03-01</p> <p>Oxyfluoride glasses doped with rare <span class="hlt">earth</span> ions (Dy3+, Er3+ or Ho3+) were fabricated, and their visible and near infrared emissions were evaluated before and after the formation of β-PbF2 nanocrystals. Upon heat treatment of the parent glass to precipitate β-PbF2 nanocrystals, both the intensity and lifetime of radiative emissions from the Dy3+ ion were improved conspicuously, whereas changes in the emissions from Er3+ and Ho3+ turned out to be relatively insignificant. In addition to the hypersensitive nature of some 4 f↔4 f transitions of Dy3+, its spatial distribution inside the heat-treated oxyfluoride samples is believed to be responsible for this interesting observation. Our finding thus exemplifies the chemical <span class="hlt">effects</span> of rare <span class="hlt">earth</span> ions on the formation of nanocrystals via heat treating oxyfluoride glasses. Various probes including X-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy and Judd-Ofelt analysis were applied to elucidate the rare <span class="hlt">earth</span> dependence of the fluoride nanocrystals within the oxyfluoride glasses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhTea..53..554O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhTea..53..554O"><span id="translatedtitle">Introducing <span class="hlt">Earth</span>'s Orbital Eccentricity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oostra, Benjamin</p> <p>2015-12-01</p> <p>Most students know that planetary orbits, including <span class="hlt">Earth</span>'s, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this <span class="hlt">effect</span> is somehow responsible for the seasons. In fact, the <span class="hlt">Earth</span>'s orbital eccentricity is small, and its only <span class="hlt">effect</span> on the seasons is their unequal durations. Here I show a pleasant way to guide students to the actual value of <span class="hlt">Earth</span>'s orbital eccentricity, starting from the durations of the four seasons. The date of perihelion is also found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790016582','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790016582"><span id="translatedtitle">Down to <span class="hlt">earth</span> relativity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shapiro, I. I.</p> <p>1978-01-01</p> <p>The basic concepts of the special and general theories of relativity are described. Simple examples are given to illustrate the <span class="hlt">effect</span> of relativity on measurements of time and frequency in the near-<span class="hlt">earth</span> environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21294521','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21294521"><span id="translatedtitle">Optically active mixed (phthalocyaninato)(porphyrinato) rare <span class="hlt">earth</span> triple-decker complexes. Synthesis, spectroscopy, and <span class="hlt">effective</span> chiral information transfer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lu, Jitao; Deng, Yanhua; Zhang, Xiaomei; Kobayashi, Nagao; Jiang, Jianzhuang</p> <p>2011-03-21</p> <p>With the view to creating novel sandwich-type tetrapyrrole rare <span class="hlt">earth</span> complexes toward potential applications in material science and chiral catalysis, two new optically active mixed (phthalocyaninato)(porphyrinato) rare <span class="hlt">earth</span> triple-decker complexes with both (R)- and (S)-enantiomers [M(2)(Pc)(2)(TCBP)] {TCBP = Meso-tetrakis [3,4-(11,12:13,14-di(1',2'-naphtho)-1,4,7,10,15,18-hexaoxacycloeicosa-2,11,13-triene)-phenyl] porphyrinate; M = Eu (1), Y (2)} have been designed and prepared by treating optically active metal free porphyrin (R)-/(S)-H(2)TCBP with M(Pc)(2) in the presence of corresponding M(acac)(3)·nH(2)O (acac = acetylacetonate) in refluxing 1,2,4-trichlorobenzene (TCB). These novel mixed ring rare <span class="hlt">earth</span> triple-decker compounds were characterized by a wide range of spectroscopic methods including MS, (1)H NMR, IR, electronic absorption, and magnetic circular-dichroism (MCD) spectroscopic measurements in addition to elemental analysis. Perfect mirror image relationship was observed in the Soret and Q absorption regions in the circular-dichroism (CD) spectra of the (R)- and (S)-enantiomers, indicating the optically active nature of these two mixed (phthalocyaninato)(porphyrinato) rare <span class="hlt">earth</span> triple-decker complexes. This result reveals the <span class="hlt">effective</span> chiral information transfer from the peripheral chiral binaphthyl units to the porphyrin and phthalocyanine chromophores in the triple-decker molecule because of the intense π-π interaction between porphyrin and phthalocyanine rings. In addition, their electrochemical properties have also been investigated by cyclic voltammetry (CV).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESS.....310904M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESS.....310904M"><span id="translatedtitle">Formation of Close-in Super-<span class="hlt">Earths</span> by Giant Impacts: <span class="hlt">Effects</span> of Initial Eccentricities and Inclinations of Protoplanets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matsumoto, Yuji; Kokubo, Eiichiro</p> <p>2015-12-01</p> <p>Recent exoplanet observations are revealing the eccentricity and inclination distributions of exoplanets. Most of observed super-<span class="hlt">Earths</span> have small eccentricities ~ 0.01 - 0.1 and small inclinations ~ 0.03 rad (e.g., Fabrycky et al., 2014). These distributions are results of their formation processes. N-body simulations have been used to investigate accretion of close-in super-<span class="hlt">Earths</span> (e.g., Hansen & Murray 2012, Ogihara et al. 2015). Hansen & Murray (2013) showed that the averaged eccentricity of close-in super-<span class="hlt">Earths</span> formed through giant impacts in gas-free and no planetesimal environment is around 0.1. In the giant impact stage, the eccentricities and inclinations are pumped up by gravitational scattering and damped by collisions. Matsumoto et al. (2015) found that the eccentricity damping rate by a collision depends on the eccentricity and inclination and thus affects the eccentricity and inclination of planets. We investigate the <span class="hlt">effect</span> of initial eccentricities and inclinations of protoplanets on eccentricities and inclinations of planets. We perform N-body simulations with systematically changing initial eccentricities and inclinations of protoplanets independently. We find that the eccentricities and inclinations of planets barely depend on the initial eccentricities of protoplanets although the collision timescale is changed. This means that initial eccentricities of protoplanets are well relaxed through scattering and collisions. On the other hand, the initial inclinations of protoplanets affect the inclination of planets since they are not relaxed during the giant impact stage. Since the collisional timescale increases with inclinations, protoplanets with high inclinations tend to interact longer until they collide with each other. As a result, planets get large eccentricities, and the number of planets becomes small. The observed eccentricities and inclinations of super-<span class="hlt">Earths</span> can be reproduced by giant impacts of protoplanets with inclinations ~ 10-3 -10</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512646P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512646P"><span id="translatedtitle">A 24-year climatology of cloud <span class="hlt">effects</span> on the <span class="hlt">Earth</span>'s longwave radiation budget</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pyrina, Maria; Matsoukas, Christos; Fotiadi, Aggeliki; Papadimas, Christos; Hatzianastassiou, Nikos; Vardavas, Ilias</p> <p>2013-04-01</p> <p>A longwave (LW) radiative transfer model (RTM) was used together with monthly mean climatological data from global datasets to compute the global distribution of LW cloud radiative <span class="hlt">effect</span> (CRE) at the top of atmosphere (TOA), within the atmosphere and at the <span class="hlt">Earth</span>'s surface, at 2.5˚x2.5˚ latitude-longitude resolution, for the 24-year period 1984-2007. The cloud data, namely cloud cover and optical depth, were derived from the latest D2 series of the International Satellite Cloud Climatology Project (ISCCP) Project, which includes 9 cloud types, distinguishing between low-, mid- and high-level and liquid and ice clouds. Supplementary data for surface and atmospheric parameters were taken from NCEP/NCAR, ECMWF, ISCCP-D2, and TOVS datasets. On a mean annual basis and global scale, clouds are found to warm the planet, by decreasing the outgoing LW radiation at TOA, by 17.8 W/m2, to cool the atmosphere, by decreasing the LW atmospheric absorption, by 11.9 W/m2 and to heat the surface by 29.7 W/m2. Nevertheless, there is a significant spatial variability of CREs. Thus, at pixel level and on year mean basis, clouds generally decrease the thermal emission of our planet by up to about 50 W/m2 but also induce planetary cooling, by up to about 2 W/m2 over central Antarctica's regions. The presence of low and middle clouds in the atmosphere induces an atmospheric cooling, by up to about 50 W/m2, while atmospheric warming is produced by high clouds along the inter-tropical convergence zone (by up to about 30 W/m2). The net LW radiation emitted by the surface is found to be reduced by clouds by up to 55 W/m2. The model CREs were validated at TOA through comparisons against high-quality ERBE-S4 CRE values over the 5-year period 1985-1989 and also against high-quality CERES-S4 CREs over the 7-year period 2001-2007. Model CREs were found to reasonably agree with both CERES and ERBE ones, with biases equal to -9.9 W/m2 and -7.1 W/m2, standard deviations of differences equal to 4</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJA...52..366K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJA...52..366K"><span id="translatedtitle">Signature <span class="hlt">effects</span> in 2qp bands of doubly even rare-<span class="hlt">earth</span> nuclei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalra, Kawalpreet; Goel, Alpana; Jain, A. K.</p> <p>2016-12-01</p> <p>The two-quasiparticle rotational bands in deformed doubly even nuclei in the rare-<span class="hlt">earth</span> region have been studied in detail. A number of interesting features like odd-even staggering and signature inversion have been observed. The phenomenon of signature inversion/reversal is observed experimentally in 162 66Dy, 170 0Yb and 170 74W in even-even nuclei. Two quasiparticle plus rotor model (TQPRM) calculations are carried out to explain the reverse pattern of signature in 170 74W for the rotational band having configuration {(h_{11/2})p ⊗ (d_{5/2})p}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800067872&hterms=earth+energy+budget&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dearth%2527s%2Benergy%2Bbudget','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800067872&hterms=earth+energy+budget&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dearth%2527s%2Benergy%2Bbudget"><span id="translatedtitle">The <span class="hlt">effects</span> on the <span class="hlt">earth</span>'s magnetotail from shocks in the solar wind</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyon, J.; Brecht, S. H.; Fedder, J. A.; Palmadesso, P.</p> <p>1980-01-01</p> <p>A new, minimally diffusive MHD computer code has been used to simulate the time-dependent, 2D interaction of the solar wind with the <span class="hlt">earth</span>'s magnetosphere. The equilibrium with a simulated unmagnetized solar wind shows the basic features of the magnetosphere: bow shock, magnetopause, and long magnetotail. A simulated shock in the solar wind shows the presence of shock focussing in the midplane of the magnetotail. This focussing can be important in the energy budget of the plasma sheet and may have an important role in the initiation of substorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850063111&hterms=osmium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dosmium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850063111&hterms=osmium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dosmium"><span id="translatedtitle">Low <span class="hlt">earth</span> orbit environmental <span class="hlt">effects</span> on osmium and related optical thin-film coatings</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gull, T. R.; Herzig, H.; Osantowski, J. F.; Toft, A. R.</p> <p>1985-01-01</p> <p>A number of samples of optical thin film materials were flown on Shuttle flight STS-8 as part of an experiment to evaluate their interaction with residual atomic oxygen in low <span class="hlt">earth</span> orbit. Osmium was selected because of its usefulness as a reflective optical coating for far-UV instruments and for confirmation of results from previous Shuttle flights in which such coatings disappeared. Reflectance data and photographic evidence are presented to support the hypothesis that the osmium disappearance is due to reaction with oxygen to form a volatile oxide. Platinum and iridium, which were included for comparison, fared much better.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000064110','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000064110"><span id="translatedtitle">Issues and <span class="hlt">Effects</span> of Atomic Oxygen Interactions With Silicone Contamination on Spacecraft in Low <span class="hlt">Earth</span> Orbit</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Banks, Bruce; Rutledge, Sharon; Sechkar, Edward; Stueber, Thomas; Snyder, Aaron; deGroh, Kim; Haytas, Christy; Brinker, David</p> <p>2000-01-01</p> <p>The continued presence and use of silicones on spacecraft in low <span class="hlt">Earth</span> orbit (LEO) has been found to cause the deposition of contaminant films on surfaces which are also exposed to atomic oxygen. The composition and optical properties of the resulting SiO(x)- based (where x is near 2) contaminant films may be dependent upon the relative rates of arrival of atomic oxygen, silicone contaminant and hydrocarbons. This paper presents results of in-space silicone contamination tests, ground laboratory simulation tests and analytical modeling to identify controlling processes that affect contaminant characteristics.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JMagR.148..277S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JMagR.148..277S"><span id="translatedtitle">Iterative Lineshape Analysis of <span class="hlt">Quadrupolar</span> Echo Spectra of a Damped CD 3 Quantum Rotor: Preliminary Evidence of a Novel Mechanism of Stochastic Spin Exchange</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szymański, S.; Olejniczak, Z.; Detken, A.; Haeberlen, U.</p> <p>2001-02-01</p> <p>It is demonstrated that the wealth of information about damped quantum rotation of CD3 groups, contained in <span class="hlt">quadrupolar</span> echo spectra, can be fully explored in a broad temperature range using a method of iterative analysis of the spectral lineshapes. The recently reported lineshape equation which, apart from the quantum tunneling and the dissipative Alexander-Binsch terms, contains an additional dissipative term having no classical analog is shown to be capable of describing even subtle details of the spectra of a crystal of acetylsalicylic acid-CD3 oriented specifically in the magnetic field. Preliminary evidence of the occurrence of this novel dissipative mechanism in the system studied is reported. The results obtained seem to suggest that there is no "classical limit" in the dissipative behavior of this system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJMPS..3660014T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJMPS..3660014T"><span id="translatedtitle">Space-fractional Schrödinger equation for a <span class="hlt">quadrupolar</span> triple Dirac-δ potential: Central Dirac-δ well and barrier cases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tare, Jeffrey D.; Esguerra, Jose Perico H.</p> <p>2015-01-01</p> <p>We solve the space-fractional Schrödinger equation for a <span class="hlt">quadrupolar</span> triple Dirac-δ (QTD-δ) potential for all energies using the momentum-space approach. For the E < 0 solution, we consider two cases, i.e., when the strengths of the potential are V0 > 0 (QTD-δ potential with central Dirac-δ well) and V0 < 0 (QTD-δ potential with central Dirac-δ barrier) and derive expressions satisfied by the bound-state energy. For all fractional orders α considered, we find that there is one eigenenergy when V0 > 0, and there are two eigenenergies when V0 < 0. We also obtain both bound- and scattering-state (E > 0) wave functions and express them in terms of Fox's H-function.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850051334&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850051334&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtechnologie"><span id="translatedtitle">Correlated observations of substorm <span class="hlt">effects</span> in the near-<span class="hlt">earth</span> region and the deep magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scholer, M.; Baumjohann, W.; Baker, D. N.; Bame, S. J.; Gloeckler, G.; Ipavich, F. M.; Smith, E. J.; Tsurutani, B. T.</p> <p>1985-01-01</p> <p>Simultaneous observations of energetic particle measurements from the geosynchronous satellite 1982-019 and magnetic field, electron plasma, and energetic proton and electron measurements obtained with ISEE 3 in the deep tail are presented. The data are supplemented by ground magnetograms. A substorm occurred on March 22, 1983, close to 0300 UT as identified in the ground magnetograms and by a particle injection at geosynchronous orbit. About 10 min later, ISEE 3 observed (at a distance of approximately 130 RE in the deep tail) magnetic field, plasma, and energetic particle signatures consistent with the passage of a plasmoid. After the passage of the plasmoid the satellite enters shortly into a lobelike environment, in which an energetic proton beam is observed. High-resolution magnetic field data are indicative of small-scale structures in the postplasmoid plasma sheet. From the plasma sheet flow speed during the plasmoid's passage it is concluded that the 0300 UT substorm is responsible for its origin. This allows an approximate timing of the plasmoid release at a near-<span class="hlt">earth</span> neutral line and of the plasma sheet recovery after substorm onset, and it indicates a close relationship between processes in the near-<span class="hlt">earth</span> plasma sheet and the deep tail during substorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CeMDA.115..353K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CeMDA.115..353K"><span id="translatedtitle">A series expansion of the solid <span class="hlt">Earth</span> tide <span class="hlt">effect</span> on geopotential</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kudryavtsev, Sergey M.</p> <p>2013-04-01</p> <p>We develop analytical series representing the main part of corrections to the geopotential coefficients caused by the solid <span class="hlt">Earth</span> tides, where Love numbers are assumed to be frequency-independent. The series are compact, precise and valid over 1800 A.D.-2200 A.D. The maximum difference between the corrections given by the analytical series and their numerical values, obtained with use of the DE/LE-423 planetary/lunar ephemerides, does not exceed 0.7× 10^{-12}. A new algorithm is proposed for calculating amplitudes of the additional variations of the geopotential coefficients for frequency dependence of Love numbers. It uses the representation of the <span class="hlt">Earth</span> tide-generating potential in the standard HW95 format and takes into account the phase of tidal waves. Corrections of up to 2× 10^{-12} to the published by the IERS Conventions (2010) amplitudes of the additional variations of the geopotential coefficients are suggested. Examples of use of the obtained series in analytical theories of motion of low-altitude STARLETTE and high-altitude ETALON-1 satellites are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6073500','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6073500"><span id="translatedtitle">Risk assessment and late <span class="hlt">effects</span> of radiation in low-<span class="hlt">earth</span> orbits</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fry, R.J.M.</p> <p>1989-01-01</p> <p>The radiation dose rates in low-<span class="hlt">earth</span> orbits are dependent on the altitude and orbital inclination. The doses to which the crews of space vehicles are exposed is governed by the duration of the mission and the shielding, and in low-<span class="hlt">earth</span> orbit missions protons are the dominant particles encountered. The risk of concern with the low dose rates and the relatively low total doses of radiation that will be incurred on the space station is excess cancer. The National Council on Radiation Protection and Measurements has recently recommended career dose-equivalent limits that take into account sex and age. The new recommendations for career limits range from 1.0 Sv to 4 Sv, depending on sex and on the age at the time of their first space mission, compared to a single career limit of 4.0 Sv previously used by NASA. Risk estimates for radiated-induced cancer are evolving and changes in the current guidance may be required in the next few years. 10 refs., 1 fig., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950058942&hterms=Chandler+Wobble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DChandler%2BWobble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950058942&hterms=Chandler+Wobble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DChandler%2BWobble"><span id="translatedtitle">Revised predictions of long-period ocean tidal <span class="hlt">effects</span> on <span class="hlt">Earth</span>'s rotation rate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dickman, S. R.; Nam, Young S.</p> <p>1995-01-01</p> <p>The rotational response of <span class="hlt">Earth</span> to long-period tidal forces, embodied in a 'zonal response function,' can be expected to vary with frequency because of variable contributions by the oceans, mantle, and core. The zonal response function has been estimated from 9 years of International Radio Interferometric Surveying (IRIS) universal time (UT1) data and compared with theoretical predictions, using a spherical harmonic tide model to compute the oceans' dynamic response, at semiannual, monthly, fortnightly, and 9-day lunisolar tidal frequencies. Different amounts of mantle anelasticity have been considered for both the oceanic and soild <span class="hlt">earth</span> responses; predictions have been made assuming axial core-mantle coupling which is either complete or absent. Additionally, an extensive recalibration of the ocean model's frictional parameters was performed using constraints derived in part from Space92 polar motion data; zonal response function predictions have also been made employing this recalibrated ocean tide model. Our results indicate that any amount of core coupling can be ruled out at a fortnightly period and probably at a 9-day period, but not at a monthly period. Our results also suggest that the mantle responds purely elastically at a 9-day period but may behave increasingly anelastically at longer periods. A simple dispersive rule is postulated for periods ranging up to the 14-month Chandler wobble period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25631449','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25631449"><span id="translatedtitle"><span class="hlt">Effects</span> of electron correlations on transport properties of iron at <span class="hlt">Earth</span>'s core conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Peng; Cohen, R E; Haule, K</p> <p>2015-01-29</p> <p><span class="hlt">Earth</span>'s magnetic field has been thought to arise from thermal convection of molten iron alloy in the outer core, but recent density functional theory calculations have suggested that the conductivity of iron is too high to support thermal convection, resulting in the investigation of chemically driven convection. These calculations for resistivity were based on electron-phonon scattering. Here we apply self-consistent density functional theory plus dynamical mean-field theory (DFT + DMFT) to iron and find that at high temperatures electron-electron scattering is comparable to the electron-phonon scattering, bringing theory into agreement with experiments and solving the transport problem in <span class="hlt">Earth</span>'s core. The conventional thermal dynamo picture is safe. We find that electron-electron scattering of d electrons is important at high temperatures in transition metals, in contrast to textbook analyses since Mott, and that 4s electron contributions to transport are negligible, in contrast to numerous models used for over fifty years. The DFT+DMFT method should be applicable to other high-temperature systems where electron correlations are important.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810056998&hterms=Seamounts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSeamounts','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810056998&hterms=Seamounts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSeamounts"><span id="translatedtitle"><span class="hlt">Effects</span> of lateral resolution on the identification of volcanotectonic provinces on <span class="hlt">earth</span> and Venus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Arvidson, R. E.; Davies, G. F.</p> <p>1981-01-01</p> <p>In an attempt to learn what volcanotectonic features can still be discerned in continental and oceanic areas of the <span class="hlt">earth</span> when topographic data are degraded to simulate the data sampled by the Pioneer-Venus altimeter, two digital topographic data sets (the 30-second continental U.S. altitude data and the 30 x 30 nautical mile bathymetry data for the North Pacific) were degraded and displayed in the same way as the altimeter data from Venus. The Appalachians were reduced to a gentle swell, with a wavelength of 300 km, and a height of 500 m. The Cordillera was seen as a broad swell, 2500 km wide, and about 2 km high. The east Pacific rise, east Pacific fractures, seamount chains, the Hawaiian swell, and most trenches were discernible in the degraded Pacific data; whereas rises, transforms, seamount chains, and trenches were not seen in the Venus data, even after corrections were made for the higher surface temperature and the absence of oceans on Venus. It was concluded that a plate tectonic regime, similar to <span class="hlt">earth</span>'s does not currently appear to exist on Venus. As shown by the Cordillera data, the Pioneer-Venus information is not of sufficiently high quality to discern whether the highlands of Venus preserve evidence for orogenic events related to plate tectonics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8468339','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8468339"><span id="translatedtitle">Absolute angle measurement using the <span class="hlt">earth</span>-field-referenced hall <span class="hlt">effect</span> sensors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kolen, P T; Rhode, J P; Francis, P R</p> <p>1993-03-01</p> <p>A miniaturized absolute angle sensor utilizing Hall generators referenced to the <span class="hlt">Earth</span>'s ambient magnetic field has been developed. The sensor has three-dimensional angular sensitivity which allows the output to be self-normalized resulting in high immunity to both B-field and temperature induced errors. The individual Hall generator elements were operated with a final sensitivity of 4.07 V G-1. The <span class="hlt">Earth</span>'s field, magnitude 0.486 G with a surface declination angle of 58.2 degrees (San Diego, California), was used as the excitation/reference field. Bandwidth limiting, low-noise design, and active/passive thermal compensation techniques were employed resulting in a sensor bandwidth of DC to 100 Hz with a maximum signal-to-noise ratio of 44.5 dB. The maximum angular resolution of the sensor was measured to be +/- 0.27 degrees. Temperature induced error was measured to be less than 2% from 25 degrees C to 40 degrees C. The measurement of shoulder joint rotation was used as the test case application for the sensor with excellent agreement between theoretical and experimental performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21179837','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21179837"><span id="translatedtitle">Identifying Neutrino Mass Hierarchy at Extremely Small {theta}{sub 13} through <span class="hlt">Earth</span> Matter <span class="hlt">Effects</span> in a Supernova Signal</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dasgupta, Basudeb; Dighe, Amol; Mirizzi, Alessandro</p> <p>2008-10-24</p> <p>Collective neutrino flavor transformations deep inside a supernova are sensitive to the neutrino mass hierarchy even at extremely small values of {theta}{sub 13}. Exploiting this <span class="hlt">effect</span>, we show that comparison of the antineutrino signals from a galactic supernova in two megaton class water Cherenkov detectors, one of which is shadowed by <span class="hlt">Earth</span>, will enable us to distinguish between the hierarchies if sin{sup 2}{theta}{sub 13} < or approx. 10{sup -5}, where long baseline neutrino experiments would be ineffectual.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20583589','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20583589"><span id="translatedtitle">[<span class="hlt">Effect</span> of processes in the <span class="hlt">earth</span>'s crust on evolution of photosynthesis (as indicated by data on carbon isotopic composition)].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ivlev, A A</p> <p>2010-01-01</p> <p>A probable mechanism of <span class="hlt">effect</span> of processes occurring in the <span class="hlt">Earth</span>'s crust on evolution of photosynthesis is considered. According to the hypothesis, this <span class="hlt">effect</span> is realized through entrance to the <span class="hlt">Earth</span>'s atmosphere of carbon dioxide that stimulates photosynthesis. Supply of CO2 is irregular and is due to irregular movements of the <span class="hlt">Earth</span>'s crust plates. This is accompanied by destruction of carbonates and conversion of carbon of the organic matter to CO2 due to processes of reduction of sulfates. The CO2 content in atmosphere rises for relatively short orogenic periods, due to intensive crust plate movement, while for the subsequent long periods, called the geosynclinal ones, of the relatively slow plate movement, the CO2 content falls due to the higher rate of its consumption for photosynthesis. Owing to the carbon isotopic fractionation accompanying photosynthesis, regular isotopic differences appear between the atmospheric CO2 and the "living" matter (Relay's <span class="hlt">effect</span>); these differences are then transformed to isotope differences of the carbonate and organic carbon. At the appearance in atmosphere of free oxygen--product of photosynthesis--in organisms there appears photorespiration that also is accompanied by fractionation of carbon isotopes, but with <span class="hlt">effect</span> of opposite sign. This leads to enrichment of the photosynthesizing biomass with 13C isotope at the orogenic periods. As a result, the initially pronounced isotope differences of the carbonate and organic carbon decrease by the end of the geosyclinal periods. According to the proposed model, concentrations of CO2 and O2 are exchanged in the antiphase. They lead to alternation of periods of warning up and cooling off on the <span class="hlt">Earth</span>. The former coincide with the orogenic periods, the latter appear at the end of geosyclinal periods when oxygen is accumulated in atmosphere, while organic substance in sediments. Accumulation of organic substance leads to formation of petroleum-maternal masses. To substantiate the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740020962&hterms=growing+season&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgrowing%2Bseason','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740020962&hterms=growing+season&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgrowing%2Bseason"><span id="translatedtitle">Magnetometeorology: Relationships between the weather and the <span class="hlt">earth</span>'s magnetic field. [solar cycle <span class="hlt">effects</span> on length of growing season</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, J. W.; Willis, D. M.</p> <p>1974-01-01</p> <p>A comparison of meteorological pressures and the strength of the <span class="hlt">earth</span>'s magnetic field suggests that the magnetic field exerts, through some unknown process, a controlling influence on the average pressure in the troposphere at high latitudes. Changes in the length of the growing season are related to the solar cycle <span class="hlt">effects</span> on the geomagnetic field. On average, the growing season is about 25 days longer near sunspot maximum than near sunspot minimum. Comparison of growing season and solar data reveals the geophysically interesting fact that the growing season tends to be the longest about a year after sunspot maximum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820004428','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820004428"><span id="translatedtitle">Handbook for the estimation of microwave propagation <span class="hlt">effects</span>: Link calculations for <span class="hlt">earth</span>-space paths (path loss and noise estimation)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Crane, R. K.; Blood, D. W.</p> <p>1979-01-01</p> <p>A single model for a standard of comparison for other models when dealing with rain attenuation problems in system design and experimentation is proposed. Refinements to the Global Rain Production Model are incorporated. Path loss and noise estimation procedures as the basic input to systems design for <span class="hlt">earth</span>-to-space microwave links operating at frequencies from 1 to 300 GHz are provided. Topics covered include gaseous absorption, attenuation by rain, ionospheric and tropospheric scintillation, low elevation angle <span class="hlt">effects</span>, radome attenuation, diversity schemes, link calculation, and receiver noise emission by atmospheric gases, rain, and antenna contributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980000679','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980000679"><span id="translatedtitle">Discover <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>Discover <span class="hlt">Earth</span> is a NASA-funded project for teachers of grades 5-12 who want to expand their knowledge of the <span class="hlt">Earth</span> system, and prepare to become master teachers who promote <span class="hlt">Earth</span> system science in their own schools, counties, and throughout their state. Participants from the following states are invited to apply: Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Washington, DC. Teachers selected for the project participate in a two-week summer workshop conducted at the University of Maryland, College Park; develop classroom-ready materials during the workshop for broad dissemination; conduct a minimum of two peer training activities during the coming school year; and participate in other enrichment/education opportunities as available and desired. Discover <span class="hlt">Earth</span> is a team effort that utilizes expertise from a range of contributors, and balances science content with hands-on classroom applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990042409&hterms=earth+nutation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearth%2Bnutation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990042409&hterms=earth+nutation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearth%2Bnutation"><span id="translatedtitle"><span class="hlt">Earth</span> Rotation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dickey, Jean O.</p> <p>1995-01-01</p> <p>The study of the <span class="hlt">Earth</span>'s rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of <span class="hlt">Earth</span> orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the <span class="hlt">Earth</span> would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the <span class="hlt">Earth</span>'s crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid <span class="hlt">Earth</span>'s axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of <span class="hlt">Earth</span> rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of <span class="hlt">Earth</span> rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid <span class="hlt">Earth</span> to variety of surface and internal stresses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/767436','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/767436"><span id="translatedtitle"><span class="hlt">Earth</span> materials and <span class="hlt">earth</span> dynamics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bennett, K; Shankland, T.</p> <p>2000-11-01</p> <p>In the project ''<span class="hlt">Earth</span> Materials and <span class="hlt">Earth</span> Dynamics'' we linked fundamental and exploratory, experimental, theoretical, and computational research programs to shed light on the current and past states of the dynamic <span class="hlt">Earth</span>. Our objective was to combine different geological, geochemical, geophysical, and materials science analyses with numerical techniques to illuminate active processes in the <span class="hlt">Earth</span>. These processes include fluid-rock interactions that form and modify the lithosphere, non-linear wave attenuations in rocks that drive plate tectonics and perturb the <span class="hlt">earth</span>'s surface, dynamic recrystallization of olivine that deforms the upper mantle, development of texture in high-pressure olivine polymorphs that create anisotropic velocity regions in the convecting upper mantle and transition zone, and the intense chemical reactions between the mantle and core. We measured physical properties such as texture and nonlinear elasticity, equation of states at simultaneous pressures and temperatures, magnetic spins and bonding, chemical permeability, and thermal-chemical feedback to better characterize <span class="hlt">earth</span> materials. We artificially generated seismic waves, numerically modeled fluid flow and transport in rock systems and modified polycrystal plasticity theory to interpret measured physical properties and integrate them into our understanding of the <span class="hlt">Earth</span>. This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM..ED22A01D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM..ED22A01D"><span id="translatedtitle">Digital <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de La Beaujardiere, J.</p> <p>2001-05-01</p> <p>Digital <span class="hlt">Earth</span> (DE) seeks to make geospatial information broadly and easily available. Vast amounts of natural and cultural information are gathered about the <span class="hlt">Earth</span>, but it is often difficult to find needed data, to share knowledge across disciplines, and to combine information from several sources. DE defines a framework for interoperability by selecting relevant open standards from the information technology community. These standards specify the technical means by which publishers can provide or sell their data, and by which client applications can find and access data in an automated fashion. The standardized DE framework enables many types of clients--from web browsers to museum kiosks to research-grade virtual environments--to use a common geospatial information infrastructure. Digital <span class="hlt">Earth</span> can benefit <span class="hlt">Earth</span> system education in general, and DLESE in particular, in several ways. First, educators, students and creators of instructional material will benefit from standardized access to georeferenced data. Secondly, educational lesson plans that focus on a region or aspect of the <span class="hlt">Earth</span> can themselves be considered geospatial information resources that could be cataloged and retrieved through DE. Finally, general public knowledge about our planet will by increased by Digital <span class="hlt">Earth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhRvD..79k3007G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhRvD..79k3007G"><span id="translatedtitle">Realistic <span class="hlt">Earth</span> matter <span class="hlt">effects</span> and a method to acquire information about small θ13 in the detection of supernova neutrinos</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Xin-Heng; Huang, Ming-Yang; Young, Bing-Lin</p> <p>2009-06-01</p> <p>In this paper, we first calculate the realistic <span class="hlt">Earth</span> matter <span class="hlt">effects</span> in the detection of type II supernova neutrinos at the Daya Bay reactor neutrino experiment which is currently under construction. It is found that the <span class="hlt">Earth</span> matter <span class="hlt">effects</span> depend on the neutrino incident angle θ, the neutrino mass hierarchy Δm312, the crossing probability at the high resonance region inside the supernova, PH, the neutrino temperature, Tα, and the pinching parameter in the neutrino spectrum, ηα. We also take into account the collective <span class="hlt">effects</span> due to neutrino-neutrino interactions inside the supernova. With the expression for the dependence of PH on the neutrino mixing-angle θ13, we obtain the relations between θ13 and the event numbers for various reaction channels of supernova neutrinos. Using these relations, we propose a possible method to acquire information about θ13 smaller than 1.5°. Such a sensitivity cannot be achieved by the reactor neutrino deta at the Daya Bay experiment which has a sensitivity of the order of θ13˜3°. Furthermore, we apply this method to other neutrino experiments, i.e. Super-K, SNO, KamLAND, LVD, MinBooNE, Borexino, and Double-Chooz. We also study the energy spectra of the differential event numbers, dN/dE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JSSCh.171..445B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JSSCh.171..445B"><span id="translatedtitle">Using EPR spectroscopy to go from the Jahn-Teller <span class="hlt">effect</span> to nuclear waste disposal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boatner, L. A.</p> <p>2003-02-01</p> <p>Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique for elucidating the fundamental solid-state-chemical and crystal-field ground-state electronic properties of rare-<span class="hlt">earth</span> and actinide ions that are incorporated into single-crystal host materials. In the case of rare-<span class="hlt">earth</span> or rare-<span class="hlt">earth</span>-like ions that are characterized by a degenerate orbital doublet ground state when placed in a cubic crystal field, EPR has proven to be an extremely valuable approach to the study of various manifestations of the Jahn-Teller (J-T) <span class="hlt">effect</span>. The contributions of EPR spectroscopy to the study of the J-T <span class="hlt">effect</span> in ions such as La 2+, Y 2+ and Sc 2+ include the discovery of <span class="hlt">quadrupolar</span> <span class="hlt">effects</span> in J-T systems and a verification of Frank Ham's theory of the dynamic J-T <span class="hlt">effect</span>. Such basic studies can often have unforeseen consequences—like leading to the discovery of new scintillators for gamma-ray detection or the development of a matrix for the disposal of radioactive waste.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A53D0210C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A53D0210C"><span id="translatedtitle">The <span class="hlt">effects</span> of atmospheric chemistry on radiation budget in the Community <span class="hlt">Earth</span> Systems Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, Y.; Czader, B.; Diao, L.; Rodriguez, J.; Jeong, G.</p> <p>2013-12-01</p> <p>The Community <span class="hlt">Earth</span> Systems Model (CESM)-Whole Atmosphere Community Climate Model (WACCM) simulations were performed to study the impact of atmospheric chemistry on the radiation budget over the surface within a weather prediction time scale. The secondary goal is to get a simplified and optimized chemistry module for the short time period. Three different chemistry modules were utilized to represent tropospheric and stratospheric chemistry, which differ in how their reactions and species are represented: (1) simplified tropospheric and stratospheric chemistry (approximately 30 species), (2) simplified tropospheric chemistry and comprehensive stratospheric chemistry from the Model of Ozone and Related Chemical Tracers, version 3 (MOZART-3, approximately 60 species), and (3) comprehensive tropospheric and stratospheric chemistry (MOZART-4, approximately 120 species). Our results indicate the different details in chemistry treatment from these model components affect the surface temperature and impact the radiation budget.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22424449','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22424449"><span id="translatedtitle">Alkaline <span class="hlt">earth</span> metal cation exchange: <span class="hlt">effect</span> of mobile counterion and dissolved organic matter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Indarawis, Katrina; Boyer, Treavor H</p> <p>2012-04-17</p> <p>The goal of this research was to provide an improved understanding of the interactions between alkaline <span class="hlt">earth</span> metals and DOM under conditions that are encountered during drinking water treatment with particular focus on cation exchange. Both magnetically enhanced and nonmagnetic cation exchange resins were converted to Na, Mg, Ca, Sr, and Ba mobile counterion forms as a novel approach to investigate the exchange behavior between the cations and the interactions between the cations and DOM. The results show that cation exchange is a robust process for removal of Ca(2+) and Mg(2+) considering competition with cations on the resin surface and presence of DOM. DOM was actively involved during the cation exchange process through complexation, adsorption, and coprecipitation reactions. In addition to advancing the understanding of ion exchange processes for water treatment, the results of this work are applicable to membrane pretreatment to minimize fouling, treatment of membrane concentrate, and precipitative softening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890003221','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890003221"><span id="translatedtitle">Atomic oxygen <span class="hlt">effects</span> on candidate coatings for long-term spacecraft in low <span class="hlt">earth</span> orbit</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lan, E. H.; Smith, Charles A.; Cross, J. B.</p> <p>1988-01-01</p> <p>Candidate atomic oxygen protective coatings for long-term low <span class="hlt">Earth</span> orbit (LEO) spacecraft were evaluated using the Los Alamos National Laboratory O-atom exposure facility. The coatings studied include Teflon, Al2O3, SiO2, and SWS-V-10, a silicon material. Preliminary results indicate that sputtered PTFE Teflon (0.1 micrometers) has a fluence lifetime of 10 to the 19th power O-atoms/cm (2), and sputtered silicon dioxide (0.1 micrometers), aluminum oxide (0.1 micrometers), and SWS-V-10, a silicone, (4 micrometers) have fluence lifetimes of 10 to the 20th power to 10 to the 21st power O-atoms/cm (2). There are large variations in fluence lifetime data for these coatings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981igrs.symp..219C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981igrs.symp..219C"><span id="translatedtitle">Miniature interferometer terminals for <span class="hlt">earth</span> surveying /MITES/ - Geodetic results and multipath <span class="hlt">effects</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Counselman, C. C., III</p> <p></p> <p>Experiments which confirm theoretical predictions regarding the use of MITES terminals for measuring baseline vectors on the ground using interferometric observations of <span class="hlt">earth</span>-orbiting satellites are presented. A set of five global positioning satellites (GPS) were observed by MITES antennas at 1.3 hour time intervals on each of two days, and it is found that this distribution facilitates the correct resolution of interferometer fringe ambiguities. In addition, experiments show that multipath interference does not pose significant problems at the centimeter level. MITES is still being developed using baseline lengths of up to 4,000 km, and a new system should demonstrate improved geodetic accuracy, and will probably require one hour observation intervals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7006962','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7006962"><span id="translatedtitle"><span class="hlt">Effect</span> of disordering in rare <span class="hlt">earth</span> titanates on their Raman spectra</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mel'nik, N.N.; Tsapenko, L.M.</p> <p>1986-09-01</p> <p>The authors study the rare <span class="hlt">earth</span> titanates obtained by quenching from the melt using Raman spectroscopy. Secimens with the general formula Ln/sub 2/Ti/sub 2/O/sub 7/ and Ln/sub 2/TiO/sub 5/ (Ln = La to Lu, Y) were prepared by melting the initial oxides on a Uran beam-heating unit, followed by quenching on a cooled substrate. The Raman spectra were excited by an argon laser and recorded by means of a double monochromator in the photon counting regime. With an increase in the rate of quenching the structure was altered for certain specimens, this being established from the x-ray diffraction patterns and the Raman spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910011422','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910011422"><span id="translatedtitle">The <span class="hlt">effect</span> of atomic oxygen on polysiloxane-polyimide for spacecraft applications in low <span class="hlt">Earth</span> orbit</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rutledge, Sharon K.; Cooper, Jill M.; Olle, Raymond M.</p> <p>1991-01-01</p> <p>Polysiloxane-polyimide films are of interest as a replacement for polyimide Kapton in the Space Station Freedom solar array blanket. The blanket provides the structural support for the solar cells as well as providing transport of heat away from the back of the cells. Polyimide Kapton would be an ideal material to use; however, its high rate of degradation due to attack by atomic oxygen in low <span class="hlt">Earth</span> orbit, at the altitudes Space Station Freedom will fly, is of such magnitude that if left unprotected, the blanket will undergo structural failure in much less than the desired 15 year operating life. Polysiloxane-polyimide is of interest as a replacement material because it should from its own protective silicon dioxide coating upon exposure to atomic oxygen. Mass, optical, and photomicrographic data obtained in the evaluation of the durability of polysiloxane-polyimide to an atomic oxygen environment are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21838699','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21838699"><span id="translatedtitle"><span class="hlt">Effects</span> of rare <span class="hlt">earth</span> elements and REE-binding proteins on physiological responses in plants.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Dongwu; Wang, Xue; Chen, Zhiwei</p> <p>2012-02-01</p> <p>Rare <span class="hlt">earth</span> elements (REEs), which include 17 elements in the periodic table, share chemical properties related to a similar external electronic configuration. REEs enriched fertilizers have been used in China since the 1980s. REEs could enter the cell and cell organelles, influence plant growth, and mainly be bound with the biological macromolecules. REE-binding proteins have been found in some plants. In addition, the chlorophyll activities and photosynthetic rate can be regulated by REEs. REEs could promote the protective function of cell membrane and enhance the plant resistance capability to stress produced by environmental factors, and affect the plant physiological mechanism by regulating the Ca²⁺ level in the plant cells. The focus of present review is to describe how REEs and REE-binding proteins participate in the physiological responses in plants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4701436','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4701436"><span id="translatedtitle"><span class="hlt">Effect</span> of Composition and Impurities on the Phosphorescence of Green-Emitting Alkaline <span class="hlt">Earth</span> Aluminate Phosphor</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kim, Doory; Kim, Han-Eol; Kim, Chang-Hong</p> <p>2016-01-01</p> <p>Recent improvements to SrAl2O4:Eu2+, Dy3+ phosphors have enabled the use of luminescent hosts with a stable crystal structure and high physical and chemical stability, thus overcoming the bottleneck in the applicability of ZnS:Cu phosphors. However, enhancement of afterglow lifetime and brightness in SrAl2O4:Eu2+, Dy3+ phosphors remains a challenging task. Here, we have improved the afterglow characteristics in terms of persistence time and brightness by a systematic investigation of the composition of Eu-doped alkaline <span class="hlt">earth</span> aluminate SrAl2O4:Eu2+, Dy3+ crystals. We found that a Dy3+/Eu2+ ratio of ~2.4 and ~0.935 mol Eu2+ (per mol of SrAl2O4) gave the brightest and longest emissions (11% and 9% increase for each). Doping with Si4+ also resulted in a slight increase in brightness up to ~15%. Doping with alkali metal or alkaline <span class="hlt">earth</span> metal significantly enhanced the phosphorescence intensity. In particular, doping with 0.005 mol Li+ (per mol of SrAl2O4) alone boosted the phosphorescence intensity to 239% of the initial value, as compared to that observed for the non-doped crystal, while doping with 0.01 mol Mg2+ and 0.005 mol Li+ (per 1 mol SrAl2O4) boosted the phosphorescence intensity up to 313% of the initial value. The results of this investigation are expected to act as a guideline for the synthesis of bright and long persistent phosphors, and facilitate the development of persistent phosphors with afterglow characteristics superior to those of conventional phosphors. PMID:26731086</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1786j0008M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1786j0008M"><span id="translatedtitle">Material exposure <span class="hlt">effects</span> in a simulated low-<span class="hlt">Earth</span> orbit environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maldonado, C.; McHarg, G.; Asmolova, O.; Andersen, G.; Rodrigues, S.; Ketsdever, A.</p> <p>2016-11-01</p> <p>Spacecraft operating in low-<span class="hlt">Earth</span> orbit (LEO) are subjected to a number of hazardous environmental constituents that can lead to decreased system performance and reduced operational lifetimes. Due to their thermal, optical, and mechanical properties, polymers are used extensively in space systems; however they are particularly susceptible to material erosion and degradation as a result of exposure to the LEO environment. The focus of this research is to examine the material erosion and mass loss experienced by the Novastrat 500 polyimide due to exposure in a simulated LEO environment. In addition to the polymer samples, chrome, silver and gold specimens will be examined to measure the oxidation rate and act as a control specimen, respectively. A magnetically filtered atomic oxygen plasma source has previously been developed and characterized for the purpose of simulating the low-<span class="hlt">Earth</span> orbit environment. The plasma source can be operated at a variety of discharge currents and gas flow rates, of which the plasma parameters downstream of the source are dependent. The characteristics of the generated plasma were examined as a function of these operating parameters to optimize the production of O+ ions with energy relevant to LEO applications, where the ram energy of the ions due to the motion of the satellite relative to the LEO plasma is high (e.g. 7800 m/s, which corresponds to approximately 5 eV of kinetic energy for O+ ions). The plasma downstream of the source consists of streaming ions with energy of approximately 5 eV and an ion species fraction that is approximately 90% O+.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19400731','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19400731"><span id="translatedtitle">The <span class="hlt">effect</span> of lunarlike satellites on the orbital infrared light curves of <span class="hlt">Earth</span>-analog planets.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moskovitz, Nicholas A; Gaidos, Eric; Williams, Darren M</p> <p>2009-04-01</p> <p>We have investigated the influence of lunarlike satellites on the infrared orbital light curves of <span class="hlt">Earth</span>-analog extrasolar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet and determine its orbit. We used an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon, and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of <span class="hlt">Earth</span>, while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g., via spectroscopy or visible-wavelength detection of specular glint from a surface ocean), only the largest (approximately Mars-sized) lunarlike satellites can be detected by light curve data from a TPF-like instrument (i.e., one that achieves a photometric signal-to-noise ratio of 10 to 20 at infrared wavelengths). Nondetection of a lunarlike satellite can obfuscate the interpretation of a given system's infrared light curve so that it may resemble a single planet with high obliquity, different orbital longitude of vernal equinox relative to inferior conjunction, and in some cases drastically different thermal characteristics. If the thermal properties of the planet are not independently established, then the presence of a lunarlike satellite cannot be inferred from infrared data, which would thus demonstrate that photometric light curves alone can only be used for preliminary study, and the addition of spectroscopic data will be necessary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040142373','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040142373"><span id="translatedtitle">Boiling Heat Transfer Mechanisms in <span class="hlt">Earth</span> and Low Gravity: Boundary Condition and Heater Aspect Ratio <span class="hlt">Effects</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kim, Jungho</p> <p>2004-01-01</p> <p>Boiling is a complex phenomenon where hydrodynamics, heat transfer, mass transfer, and interfacial phenomena are tightly interwoven. An understanding of boiling and critical heat flux in microgravity environments is of importance to space based hardware and processes such as heat exchange, cryogenic fuel storage and transportation, electronic cooling, and material processing due to the large amounts of heat that can be removed with relatively little increase in temperature. Although research in this area has been performed in the past four decades, the mechanisms by which heat is removed from surfaces in microgravity are still unclear. Recently, time and space resolved heat transfer data were obtained in both <span class="hlt">earth</span> and low gravity environments using an array of microheaters varying in size between 100 microns to 700 microns. These heaters were operated in both constant temperature as well as constant heat flux mode. Heat transfer under nucleating bubbles in <span class="hlt">earth</span> gravity were directly measured using a microheater array with 100 m resolution operated in constant temperature mode with low and high subcooled bulk liquid along with images from below and from the side. The individual bubble departure diameter and energy transfer were larger with low subcooling but the departure frequency increased at high subcooling, resulting in higher overall heat transfer. The bubble growth for both subcoolings was primarily due to energy transfer from the superheated liquid layer relatively little was due to wall heat transfer during the bubble growth process. Oscillating bubbles and sliding bubbles were also observed in highly subcooled boiling. Transient conduction and/or microconvection was the dominant heat transfer mechanism in the above cases. A transient conduction model was developed and compared with the experimental data with good agreement. Data was also obtained with the heater array operated in a constant heat flux mode and measuring the temperature distribution across</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930048273&hterms=earth+nutation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dearth%2Bnutation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930048273&hterms=earth+nutation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dearth%2Bnutation"><span id="translatedtitle">The <span class="hlt">effect</span> of ocean tides on the <span class="hlt">earth</span>'s rotation as predicted by the results of an ocean tide model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gross, Richard S.</p> <p>1993-01-01</p> <p>The published ocean tidal angular momentum results of Seiler (1991) are used to predict the <span class="hlt">effects</span> of the most important semidiurnal, diurnal, and long period ocean tides on the <span class="hlt">earth</span>'s rotation. The separate, as well as combined, <span class="hlt">effects</span> of ocean tidal currents and sea level height changes on the length-of-day, UT1, and polar motion are computed. The predicted polar motion results reported here account for the presence of the free core nutation and are given in terms of the motion of the celestial ephemeris pole so that they can be compared directly to the results of observations. Outside the retrograde diurnal tidal band, the summed <span class="hlt">effect</span> of the semidiurnal and diurnal ocean tides studied here predict peak-to-peak polar motion amplitudes as large as 2 mas. Within the retrograde diurnal tidal band, the resonant enhancement caused by the free core nutation leads to predicted polar motion amplitudes as large as 9 mas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080044712','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080044712"><span id="translatedtitle">Cloud <span class="hlt">Effects</span> on Meridional Atmospheric Energy Budget Estimated from Clouds and the <span class="hlt">Earth</span>'s Radiant Energy System (CERES) Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kato, Seiji; Rose, Fred G.; Rutan, David A.; Charlock, Thomas P.</p> <p>2008-01-01</p> <p>The zonal mean atmospheric cloud radiative <span class="hlt">effect</span>, defined as the difference of the top-of-atmosphere (TOA) and surface cloud radiative <span class="hlt">effects</span>, is estimated from three years of Clouds and the <span class="hlt">Earth</span>'s Radiant Energy System (CERES) data. The zonal mean shortwave <span class="hlt">effect</span> is small, though it tends to be positive (warming). This indicates that clouds increase shortwave absorption in the atmosphere, especially in midlatitudes. The zonal mean atmospheric cloud radiative <span class="hlt">effect</span> is, however, dominated by the longwave <span class="hlt">effect</span>. The zonal mean longwave <span class="hlt">effect</span> is positive in the tropics and decreases with latitude to negative values (cooling) in polar regions. The meridional gradient of cloud <span class="hlt">effect</span> between midlatitude and polar regions exists even when uncertainties in the cloud <span class="hlt">effect</span> on the surface enthalpy flux and in the modeled irradiances are taken into account. This indicates that clouds increase the rate of generation of mean zonal available potential energy. Because the atmospheric cooling <span class="hlt">effect</span> in polar regions is predominately caused by low level clouds, which tend to be stationary, we postulate that the meridional and vertical gradients of cloud <span class="hlt">effect</span> increase the rate of meridional energy transport by dynamics in the atmosphere from midlatitude to polar region, especially in fall and winter. Clouds then warm the surface in polar regions except in the Arctic in summer. Clouds, therefore, contribute in increasing the rate of meridional energy transport from midlatitude to polar regions through the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010045818&hterms=public+health&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dpublic%2Bhealth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010045818&hterms=public+health&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dpublic%2Bhealth"><span id="translatedtitle"><span class="hlt">Earth</span>: <span class="hlt">Earth</span> Science and Health</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Maynard, Nancy G.</p> <p>2001-01-01</p> <p>A major new NASA initiative on environmental change and health has been established to promote the application of <span class="hlt">Earth</span> science remote sensing data, information, observations, and technologies to issues of human health. NASA's <span class="hlt">Earth</span> Sciences suite of <span class="hlt">Earth</span> observing instruments are now providing improved observations science, data, and advanced technologies about the <span class="hlt">Earth</span>'s land, atmosphere, and oceans. These new space-based resources are being combined with other agency and university resources, data integration and fusion technologies, geographic information systems (GIS), and the spectrum of tools available from the public health community, making it possible to better understand how the environment and climate are linked to specific diseases, to improve outbreak prediction, and to minimize disease risk. This presentation is an overview of NASA's tools, capabilities, and research advances in this initiative.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AcAau..77..197L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AcAau..77..197L"><span id="translatedtitle">A passive satellite deorbiting strategy for medium <span class="hlt">earth</span> orbit using solar radiation pressure and the J2 <span class="hlt">effect</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lücking, Charlotte; Colombo, Camilla; McInnes, Colin R.</p> <p>2012-08-01</p> <p>The growing population of space debris poses a serious risk to the future of space flight. To <span class="hlt">effectively</span> manage the increase of debris in orbit, end-of life disposal has become a key requirement for future missions. This poses a challenge for Medium <span class="hlt">Earth</span> Orbit (MEO) spacecraft which require a large Δv to re-enter the atmosphere or reach the geostationary graveyard orbit. This paper further explores a passive strategy based on the joint <span class="hlt">effects</span> of solar radiation pressure and the <span class="hlt">Earth</span>'s oblateness acting on a high area-to-mass-ratio object. The concept was previously presented as an analytical planar model. This paper uses a full 3D model to validate the analytical results numerically for equatorial circular orbits first, then investigating higher inclinations. It is shown that for higher inclinations the initial position of the Sun and right ascension of the ascending node become increasingly important. A region of very low required area-to-mass-ratio is identified in the parameter space of semi-major axis and inclination which occurs for altitudes below 10,000 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1329003','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1329003"><span id="translatedtitle">Uptake and <span class="hlt">effect</span> of rare <span class="hlt">earth</span> elements on gene expression in <i>Methylosinus trichosporium</i> OB3b</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gu, Wenyu; Farhan Ul Haque, Muhammad; DiSpirito, Alan A.; Semrau, Jeremy D.</p> <p>2016-05-12</p> <p>It is well-known that M. trichosporium OB3b has two forms of methane monooxygenase responsible for the initial conversion of methane to methanol, a cytoplasmic (soluble) methane monooxygenase (sMMO) and a membrane-associated (particulate) methane monooxygenase (pMMO) and that copper strongly regulates expression of these alternative forms of MMO. More recently, it has been discovered that M. trichosporium OB3b has multiple types of the methanol dehydrogenase (MeDH), i.e. the Mxa-MeDH and Xox-MeDH, and the expression of these two forms is regulated by the availability of the rare <span class="hlt">earth</span> element, cerium. Here we extend these studies and show that lanthanum, praseodymium, neodymium and samarium also regulate expression of alternative forms of MeDH. The <span class="hlt">effect</span> of these rare <span class="hlt">earth</span> elements on MeDH expression, however, was only observed in the absence of copper. Further, a mutant of M. trichosporium OB3b where the Mxa-MeDH was knocked out was able to grow in the presence of lanthanum, praseodymium and neodymium, but was not able to grow in the presence of samarium. In conclusion, collectively these data suggest that multiple levels of gene regulation by metals exist in M. trichosporium OB3b but that copper overrides the <span class="hlt">effect</span> of other metals by an as yet unknown mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12852978','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12852978"><span id="translatedtitle">Increasing UV-B radiation at the <span class="hlt">earth</span>'s surface and potential <span class="hlt">effects</span> on aqueous mercury cycling and toxicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bonzongo, Jean Claude J; Donkor, Augustine K</p> <p>2003-09-01</p> <p>In the past two decades, a great deal of attention has been paid to the environmental fate of mercury (Hg), and this is exemplified by the growing number of international conferences devoted uniquely to Hg cycling and its impacts on ecosystem functions and life. This interest in the biogeochemistry of Hg has resulted in a significant improvement of our understanding of its impact on the environment and human health. However, both past and current research, have been primarily oriented toward the study of direct impact of anthropogenic activities on Hg cycling. Besides a few indirect <span class="hlt">effects</span> such as the increase in Hg methylation observed in acid-rain impacted aquatic systems or the reported enhanced Hg bioaccumulation in newly flooded water reservoirs; changes in Hg transformations/fluxes that may be related to global change have received little attention. A case in point is the depletion of stratospheric ozone and the resulting increase in solar UV-radiation reaching the <span class="hlt">Earth</span>. This review and critical discussion suggest that increasing UV-B radiation at <span class="hlt">earth</span>'s surface could have a significant and complex impact on Hg cycling including <span class="hlt">effects</span> on Hg volatilization (photo-reduction), solubilization (photo-oxidation), methyl-Hg demethylation, and Hg methylation. Therefore, this paper is written to provoke discussions, and more importantly, to stimulate research on potential impacts of incoming solar UV-radiation on global Hg fluxes and any toxicity aspects of Hg that may become exacerbated by UV-radiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790012503','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790012503"><span id="translatedtitle">The <span class="hlt">effect</span> of surface reflection and clouds on the estimation of total ozone from satellite measurements. [of ultraviolet sunlight scattered from the <span class="hlt">earth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fraser, R. S.; Ahmad, Z.</p> <p>1979-01-01</p> <p>The total amount of ozone in a vertical column is being measured by Nimbus 4 and 7 observations of the intensity of ultraviolet sunlight scattered from the <span class="hlt">earth</span>. The algorithm for deriving the amount of ozone from the observations uses the assumption that the surface reflects the light isotropically and the albedo is independent of wavelength. The <span class="hlt">effects</span> of anisotropic surfaces and clouds on the estimate of total ozone are computed for models of the <span class="hlt">earth</span>-atmosphere system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..MARU12005L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..MARU12005L"><span id="translatedtitle">Replacement of Ge in GeTe by [Ag +Sb] and rare <span class="hlt">earths</span>: <span class="hlt">effect</span> on thermoelectric properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levin, E. M.; Hanson, M.; Hanus, R.; Schmidt-Rohr, K.</p> <p>2013-03-01</p> <p>High-efficiency p-type Te-Sb-Ge-Ag (TAGS) thermoelectric materials are based on the GeTe narrow-band self-dopant semiconductor where Ge can be replaced by up to 16 at.% [Ag +Sb]. To understand the <span class="hlt">effect</span> of Ge replacement by 4 at.% [Ag +Sb] as well as rare <span class="hlt">earths</span> atoms, we have synthesized and studied XRD, thermopower, electrical resistivity, thermal conductivity, and 125Te NMR of GeTe and Ag2Sb2Ge46-xRxTe50 with R =Gd, Dy and x = 1, 2. At 700 K, GeTe exhibits a thermopower of +146 μVK-1 and a large power factor, 42 μWcm-1K-2. Replacement of Ge by [Ag +Sb] and rare <span class="hlt">earths</span> enhances the thermopower, but slightly reduces the power factor due to an increase in electrical resistivity. The thermal conductivity at 300 K of all alloys studied is reduced by a factor of two compared to GeTe. 125Te NMR spin-lattice relaxation time and resonance frequency reflect changes in carrier concentration. However, decrease of thermal conductivity due to carriers and increase of electrical resistivity are mostly due to a reduction of carrier mobility and indicate strong scattering produced by [Ag +Sb] and rare <span class="hlt">earth</span> atoms. At 700 K, the thermoelectric figure of merit of GeTe is 0.8, whereas that in Ag2Sb2Ge45Dy1Te50 is much larger, 1.2, due to a reduction in thermal conductivity. Enhancement of thermopower is discussed within a model of energy filtering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..59..351T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..59..351T"><span id="translatedtitle">Long-term changes in space weather <span class="hlt">effects</span> on the <span class="hlt">Earth</span>'s ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsagouri, Ioanna; Galkin, Ivan; Asikainen, Timo</p> <p>2017-01-01</p> <p>Certain limitations that have been identified in existing ionospheric prediction capabilities indicate that the deeper understanding and the accurate formulation of the ionospheric response to external forcing remain always high priority tasks for the research community. In this respect, this paper attempts an investigation of the long-term behavior of the ionospheric disturbances from the solar minimum between the solar cycles 23 and 24 up to the solar maximum of solar cycle 24. The analysis is based on observations of the foF2 critical frequency and the hmF2 peak electron density height obtained in the European region, records of the Dst and AE indices, as well as measurements of energetic particle fluxes from NOAA/POES satellites fleet. The discussion of the ionospheric behavior in a wide range of geophysical conditions within the same solar cycle facilitates the determination of general trends in the ionospheric response to different faces of space weather driving. According to the evidence, the disturbances in the peak electron density reflect mainly the impact of geoeffective solar wind structures on the <span class="hlt">Earth</span>'s ionosphere. The intensity of the disturbances may be significant (greater than 20% with respect to normal conditions) in all cases, but the ionospheric response tends to have different characteristics between solar minimum and solar maximum conditions. In particular, in contrast to the situation in solar maximum, in solar minimum years the solar wind impact on the <span class="hlt">Earth</span>'s ionosphere is mainly built on the occurrence of ionization increases, which appear more frequent and intense than ionization depletions. The ionization enhancements are apparent in all local time sectors, but they peak in the afternoon hours, while a significant part of them seems not related with an F2 layer uplifting. Taking into account the main interplanetary drivers of the disturbances in each case, i.e. high speed streams (HSSs) and corotating interaction regions (CIRs) in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.........8E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.........8E"><span id="translatedtitle">The <span class="hlt">effects</span> of cooperative learning methods on minority ninth graders in <span class="hlt">earth</span> and space science</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eshietedoho, Cobb G.</p> <p></p> <p>This research was conducted using a quasi-experimental study design. The study took place at a local high school in the Miami-Dade County Public School System, the 4th largest school system in the nation. Students in the researcher's high school class were entering high school for the first time and were promoted into 9th grade at the end of the 2008--2009 school year. The observed problem that necessitated the study had been noticed during the writer's tenure at the school. The minority students, Blacks and Hispanics in particular, were underperforming in the researcher's <span class="hlt">earth</span> science class when compared to their White and Asian American counterparts. The researcher conducted the study for the purpose of determining whether cooperative learning through active engagement techniques could enhance these students' achievement in <span class="hlt">earth</span> and space science. The researcher used a cooperative learning technique in combination with technology integration, research activities, laboratory experimentation, and other aspects of group projects to engage students in a collaborative effort with the hope of enhancing their performance. The method involved grouping students using Kagan's numerical system. Students were placed in groups of 4, which included 1 high achiever, 2 average achievers, and 1 low achiever. The placement process utilized the incoming students' 8th-grade Florida Comprehensive Assessment Test science results. Placement was carried out after the researcher had the opportunity to observe the students so that groups did not contain friends and adversaries or all-male or all-female members. The premise for using this technique was to engage the students actively, help them become self-reliant, develop skills in teamwork, and work cooperatively to contribute equally to each other's success. A paired sample t test was conducted to evaluate the hypothesis that achievement scores from the posttest would be statistically more significant than the pretest. The test was</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAP...116f3902L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAP...116f3902L"><span id="translatedtitle">Magnetocaloric <span class="hlt">effect</span> in heavy rare-<span class="hlt">earth</span> elements doped Fe-based bulk metallic glasses with tunable Curie temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Jiawei; Huo, Juntao; Law, Jiayan; Chang, Chuntao; Du, Juan; Man, Qikui; Wang, Xinmin; Li, Run-Wei</p> <p>2014-08-01</p> <p>The <span class="hlt">effects</span> of heavy rare <span class="hlt">earth</span> (RE) additions on the Curie temperature (TC) and magnetocaloric <span class="hlt">effect</span> of the Fe-RE-B-Nb (RE = Gd, Dy and Ho) bulk metallic glasses were studied. The type of dopping RE element and its concentration can easily tune TC in a large temperature range of 120 K without significantly decreasing the magnetic entropy change (ΔSM) and refrigerant capacity (RC) of the alloys. The observed values of ΔSM and RC of these alloys compare favorably with those of recently reported Fe-based metallic glasses with enhanced RC compared to Gd5Ge1.9Si2Fe0.1. The tunable TC and large glass-forming ability of these RE doped Fe-based bulk metallic glasses can be used in a wide temperature range with the final required shapes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22391778','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22391778"><span id="translatedtitle">Inclusion of electronic polarizability <span class="hlt">effect</span> in high pressure structural properties of alloy of rare-<span class="hlt">earth</span> antimonides</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yaduvanshi, Namrata Kapoor, Shilpa; Singh, Sadhna</p> <p>2015-05-15</p> <p>In the present paper, we have investigated the high-pressure structural phase transition of rare-<span class="hlt">earth</span> antimonides (NdSb and DySb). We studied theoretically the structural properties of alloy of these compounds (NdSb and DySb) by using the three-body potential model with the <span class="hlt">effect</span> of electronic polarizability (TBIPE{sub P}). These compounds exhibit first order crystallographic phase transition from NaCl (B{sub 1}) to CsCl (B{sub 2}) phase at 17.8 GPa and 22.6 GPa respectively. The study has been extended to mixed crystals and the <span class="hlt">effect</span> of composition on transition pressure and volume change is investigated. The phase transition pressures and associated volume collapse obtained from present potential model (TBIPE{sub P}) show a good agreement with available experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920031296&hterms=earth+warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dearth%2Bwarming','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920031296&hterms=earth+warming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dearth%2Bwarming"><span id="translatedtitle"><span class="hlt">Effect</span> of cloud cover and surface type on <span class="hlt">earth</span>'s radiation budget derived from the first year of ERBE data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gibson, G. G.; Denn, F. M.; Young, D. F.; Harrison, E. F.; Minnis, P.; Barkstrom, B. R.</p> <p>1990-01-01</p> <p>One year of ERBE data is analyzed for variations in outgoing LW and absorbed solar flux. Differences in land and ocean radiation budgets as well as differences between clear-sky and total scenes, including clouds, are studied. The variation of monthly average radiative parameters is examined for February 1985 through January 1986 for selected study regions and on zonal and global scales. ERBE results show significant seasonal variations in both outgoing LW and absorbed SW flux, and a pronounced difference between oceanic and continental surfaces. The main factors determining cloud radiative forcing in a given region are solar insolation, cloud amount, cloud type, and surface properties. The strongest <span class="hlt">effects</span> of clouds are found in the midlatitude storm tracks over the oceans. Over much of the globe, LW warming is balanced by SW cooling. The annual-global average net cloud forcing shows that clouds have a net cooling <span class="hlt">effect</span> on the <span class="hlt">earth</span> for the year.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.3107L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3107L"><span id="translatedtitle">Near <span class="hlt">Earth</span> Objects and Cascading <span class="hlt">Effects</span> from the Policy Perspective: Implications from Problem and Solution Definition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lindquist, Eric</p> <p>2016-04-01</p> <p>The characterization of near-<span class="hlt">Earth</span>-objects (NEOs) in regard to physical attributes and potential risk and impact factors presents a complex and complicates scientific and engineering challenge. The societal and policy risks and impacts are no less complex, yet are rarely considered in the same context as material properties or related factors. Further, NEO impacts are typically considered as discrete events, not as initial events in a dynamic cascading system. The objective of this contribution is to position the characterization of NEOs within the public policy process domain as a means to reflect on the science-policy nexus in regard to risks and multi-hazard impacts associated with these hazards. This will be accomplished through, first, a brief overview of the science-policy nexus, followed by a discussion of policy process frameworks, such as agenda setting and the multiple streams model, focusing events, and punctuated equilibrium, and their application and appropriateness to the problem of NEOs. How, too, for example, does NEO hazard and risk compare with other low probability, high risk, hazards in regard to public policy? Finally, we will reflect on the implications of alternative NEO "solutions" and the characterization of the NEO "problem," and the political and public acceptance of policy alternatives as a way to link NEO science and policy in the context of the overall NH9.12 panel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25723777','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25723777"><span id="translatedtitle">Upconversion <span class="hlt">effective</span> enhancement by producing various coordination surroundings of rare-<span class="hlt">Earth</span> ions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Qingming; Yu, Han; Ma, En; Zhang, Xinqi; Cao, Wenbing; Yang, Chengang; Yu, Jianchang</p> <p>2015-03-16</p> <p>In this manuscript, we present a simple route to enhance upconversion (UC) emission by producing two different coordination sites of trivalent cations in a matrix material and adjusting crystal field asymmetry by Hf(4+) co-doping. A cubic phase, Y3.2Al0.32Yb0.4Er0.08F12, with these structural characteristics was synthesized successfully by introducing a small ion (Al(3+)) into YF3. X-ray diffraction (XRD), nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), X-ray spectroscopy (XPS), and fluorescence spectrophotometry (FS) were employed for its crystalline structure and luminescent property analysis. As a result, the coordination environments of the rare-<span class="hlt">earth</span> ions were varied more obviously than a hexagonal NaYF4 matrix with the same Hf(4+) co-doping concentration, with vertical comparison, UC luminescent intensities of cubic Y3.2Al0.32Yb0.4Er0.08F12 were largely enhanced (∼32-80 times greater than that of different band emissions), while the maximum enhancement of hexagonal NaYF4 was by a factor of ∼12. According to our experimental results, the mechanism has been demonstrated involving the crystalline structure, crystal field asymmetry, luminescence lifetime, hypersensitive transition, and so on. The study may be helpful for the design and fabrication of high-performance UC materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A43G0374P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A43G0374P"><span id="translatedtitle">First results on the direct <span class="hlt">effects</span> of aerosols in the Brazilian <span class="hlt">Earth</span> System Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pendharkar, J.; Alvim, D. S., Sr.; Figueroa, S. N.; Nobre, P. N.; Kubota, P. Y.</p> <p>2015-12-01</p> <p>Brazilian <span class="hlt">Earth</span> System Model (BESM) is being developed at Instituto Nacional de Pesquisas Espaciais (INPE), Brazil with a mission to build and utilize the potential to generate scenarios for future climate change, represent in the best capacity the processes relevant to Brazil's interest thereby playing a lead role in determining policies pertaining to environment and climate change, and participate in the IPCC global climate change scenarios. One of the developmental goals of BESM is to simulate the affects of aerosols in its climate model. The Hamburg Aerosol Model (HAM) is been chosen as the aerosol transport module for BESM. The implementation is categorized in three phases, of which the initialization phase has been completed. The work is underway to include the radiative affect of aerosols. We propose to present the first results of the implementation of the radiative affects of the aerosols that is, radiative forcing over different regions of Brazil with sector specific environmental conditions like forest fires, industrial, domestic etc. The initial simulations will be crucial for the BESM and will also shed light on the performance of the different radiation schemes in BESM and to its response to aerosols.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880020449','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880020449"><span id="translatedtitle">The <span class="hlt">effect</span> of the near <span class="hlt">earth</span> micrometeoroid environment on a highly reflective mirror surface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mirtich, Michael J.; Mark, Herman; Kerslake, William R.</p> <p>1988-01-01</p> <p>A resurgence of interest in placing large solar concentrator solar dynamic systems in space for power generation has brought up again a concern for maintaining the integrity of the optical properties of highly specular reflecting surfaces in the near <span class="hlt">earth</span> space environment. One of the environmental hazards needing evaluation is the micrometeoroid environment. It has been shown that highly reflective polished metals and thin film coatings degrade when exposed to simulated micrometeoroids in the lab. At NASA-Lewis, a shock tube was used to simulate the phenomenon of micrometeoroid impact by accelerating micron sized particles to hypervelocities. Any changes in the optical properties of surfaces exposed to this impact were then evaluated. The degradation of optical properties of polished metals and thin metallic films after exposure to simulated micrometeoroids was determined as a function of impacting kinetic energy area of the particles. A calibrated sensor was developed to not only detect the micrometeoroid environment, but also to evaluate the degradation of the optical properties of thin aluminum films in space. Results of the simulation are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010MMTA...41.1973N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010MMTA...41.1973N"><span id="translatedtitle"><span class="hlt">Effect</span> of Ca and Rare <span class="hlt">Earth</span> Elements on Impression Creep Properties of AZ91 Magnesium Alloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nami, B.; Razavi, H.; Mirdamadi, S.; Shabestari, S. G.; Miresmaeili, S. M.</p> <p>2010-08-01</p> <p>Creep properties of AZ91 magnesium alloy and AZRC91 (AZ91 + 1 wt pct RE + 1.2 wt pct Ca) alloy were investigated using the impression creep method. It was shown that the creep properties of AZ91 alloy are significantly improved by adding Ca and rare <span class="hlt">earth</span> (RE) elements. The improvement in creep resistance is mainly attributed to the reduction in the amount and continuity of eutectic β(Mg17Al12) phase as well as the formation of new Al11RE3 and Al2Ca intermetallic compounds at interdendritic regions. It was found that the stress exponent of minimum creep rate, n, varies between 5.69 and 6 for AZ91 alloy and varies between 5.81 and 6.46 for AZRC91 alloy. Activation energies of 120.9 ± 8.9 kJ/mol and 100.6 ± 7.1 kJ/mol were obtained for AZ91 and AZRC91 alloys, respectively. It was shown that the lattice and pipe-diffusion-controlled dislocation climb are the dominant creep mechanisms for AZ91 and AZRC91 alloys, respectively. The constitutive equations, correlating the minimum creep rate with temperature and stress, were also developed for both alloys.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920005689','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920005689"><span id="translatedtitle"><span class="hlt">Effect</span> of patch borders on coercivity in amorphous rare <span class="hlt">earth</span>-transition metal thin films</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Patterson, G.; Fu, H.; Giles, R. C.; Mansuripur, M.</p> <p>1991-01-01</p> <p>The coercivity at the micron scale is a very important property of magneto-optical media. It is a key factor that determines the magnetic domain wall movement and domain reversal. How the coercivity is influenced by a special type of patch borders is discussed. Patch formation is a general phenomenon in growth processes of amorphous rare <span class="hlt">earth</span> transition metal thin films. Different patches may stem from different seeds and the patch borders are formed when they merge. Though little is known about the exact properties of the borders, we may expect that the exchange interaction at the patch border is weaker than that within a patch, since there is usually a spatial gap between two patches. Computer simulations were performed on a 2-D hexagonal lattice consisting of 37 complete patches with random shape and size. From the series of simulations we may conclude that the domain in the patch with borders of 30 percent exchange strength can expand most easily to the whole lattice, because the exchange strength can expand most easily to the whole lattice, because the exchange strength of the border is not too high to prevent the domain from growing within the patch and it is not too low to prevent the domain from expanding beyond the patch.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRC..120.7400C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRC..120.7400C"><span id="translatedtitle">Salt precipitation in sea ice and its <span class="hlt">effect</span> on albedo, with application to Snowball <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carns, Regina C.; Brandt, Richard E.; Warren, Stephen G.</p> <p>2015-11-01</p> <p>During the initial freezing of the tropical ocean on Snowball <span class="hlt">Earth</span>, the first ice to form would be sea ice, which contains salt within inclusions of liquid brine. At temperatures below -23°C, significant amounts of the salt begin to crystallize, with the most abundant salt being hydrohalite (NaCl·2H2O). These crystals scatter light, increasing the ice albedo. In this paper, we present field measurements of the albedo of cold sea ice and laboratory measurements of hydrohalite precipitation. Precipitation of salt within brine inclusions was observed on windswept bare ice of McMurdo Sound at the coast of Antarctica (78°S) in early austral spring. Salinity and temperature were measured in ice cores. Spectral albedo was measured on several occasions during September and October. The albedo showed a gradual increase with decreasing temperature, consistent with salt precipitation. Laboratory examination of thin sections from the ice cores showed that the precipitation process exhibits hysteresis, with hydrohalite precipitating over a range of temperatures between -28°C and -35°C but dissolving at about -23°C. The causes of the hysteresis were investigated in experiments on laboratory-grown sea ice with different solute mixtures. All mixtures showed hysteresis, suggesting that it may be an inherent property of hydrohalite precipitation within brine inclusions rather than being due to biological macromolecules or interactions between various salts in seawater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1001650','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1001650"><span id="translatedtitle">Pore-fluid <span class="hlt">effects</span> on seismic waves in vertically fractured <span class="hlt">earth</span> with orthotropic symmetry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Berryman, J.G.</p> <p>2010-05-15</p> <p>For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI <span class="hlt">earth</span> system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous rocks, depending on porosity, solid moduli, and the pore-fluid bulk modulus. For heterogeneous porous media, connections between the present work and earlier related results of Brown and Korringa are also established.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981JGR....86.6917H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981JGR....86.6917H"><span id="translatedtitle">The <span class="hlt">effect</span> of the charge exchange source on the velocity and 'temperature' distributions and their anisotropies in the <span class="hlt">earth</span>'s exosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hodges, R. R., Jr.; Rohrbaugh, R. P.; Tinsley, B. A.</p> <p>1981-08-01</p> <p>The velocity distribution of atomic hydrogen in the <span class="hlt">earth</span>'s exosphere is calculated as a function of altitude and direction taking into account both the classic exobase source and the higher-altitude plasmaspheric charge exchange source. Calculations are performed on the basis of a Monte Carlo technique in which random ballistic trajectories of individual atoms are traced through a three-dimensional grid of audit zones, at which relative concentrations and momentum or energy fluxes are obtained. In the case of the classical exobase source alone, the slope of the velocity distribution is constant only for the upward radial velocity component and increases dramatically with altitude for the incoming radial and transverse velocity components, resulting in a temperature decrease. The charge exchange source, which produces the satellite hydrogen component and the hot ballistic and escape components of the exosphere, is found to enhance the wings of the velocity distributions, however this <span class="hlt">effect</span> is not sufficient to overcome the temperature decreases at altitudes above one <span class="hlt">earth</span> radius. The resulting global model of the hydrogen exosphere may be used as a realistic basis for radiative transfer calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810059623&hterms=audit&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Daudit','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810059623&hterms=audit&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Daudit"><span id="translatedtitle">The <span class="hlt">effect</span> of the charge exchange source on the velocity and 'temperature' distributions and their anisotropies in the <span class="hlt">earth</span>'s exosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hodges, R. R., Jr.; Rohrbaugh, R. P.; Tinsley, B. A.</p> <p>1981-01-01</p> <p>The velocity distribution of atomic hydrogen in the <span class="hlt">earth</span>'s exosphere is calculated as a function of altitude and direction taking into account both the classic exobase source and the higher-altitude plasmaspheric charge exchange source. Calculations are performed on the basis of a Monte Carlo technique in which random ballistic trajectories of individual atoms are traced through a three-dimensional grid of audit zones, at which relative concentrations and momentum or energy fluxes are obtained. In the case of the classical exobase source alone, the slope of the velocity distribution is constant only for the upward radial velocity component and increases dramatically with altitude for the incoming radial and transverse velocity components, resulting in a temperature decrease. The charge exchange source, which produces the satellite hydrogen component and the hot ballistic and escape components of the exosphere, is found to enhance the wings of the velocity distributions, however this <span class="hlt">effect</span> is not sufficient to overcome the temperature decreases at altitudes above one <span class="hlt">earth</span> radius. The resulting global model of the hydrogen exosphere may be used as a realistic basis for radiative transfer calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChPhB..25c7502L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChPhB..25c7502L"><span id="translatedtitle">Review of magnetic properties and magnetocaloric <span class="hlt">effect</span> in the intermetallic compounds of rare <span class="hlt">earth</span> with low boiling point metals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ling-Wei, Li</p> <p>2016-03-01</p> <p>The magnetocaloric <span class="hlt">effect</span> (MCE) in many rare <span class="hlt">earth</span> (RE) based intermetallic compounds has been extensively investigated during the last two decades, not only due to their potential applications for magnetic refrigeration but also for better understanding of the fundamental problems of the materials. This paper reviews our recent progress on studying the magnetic properties and MCE in some binary or ternary intermetallic compounds of RE with low boiling point metal(s) (Zn, Mg, and Cd). Some of them exhibit promising MCE properties, which make them attractive for low temperature magnetic refrigeration. Characteristics of the magnetic transition, origin of large MCE, as well as the potential application of these compounds are thoroughly discussed. Additionally, a brief review of the magnetic and magnetocaloric properties in the quaternary rare <span class="hlt">earth</span> nickel boroncarbides RENi2B2C superconductors is also presented. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374081 and 11004044), the Fundamental Research Funds for the Central Universities, China (Grant Nos. N150905001, L1509006, and N140901001), the Japan Society for the Promotion of Science Postdoctoral Fellowships for Foreign Researchers (Grant No. P10060), and the Alexander von Humboldt (AvH) Foundation (Research stipend to L. Li).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26ES...18a2117M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26ES...18a2117M"><span id="translatedtitle">Digital <span class="hlt">Earth</span> - A sustainable <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mahavir</p> <p>2014-02-01</p> <p>All life, particularly human, cannot be sustainable, unless complimented with shelter, poverty reduction, provision of basic infrastructure and services, equal opportunities and social justice. Yet, in the context of cities, it is believed that they can accommodate more and more people, endlessly, regardless to their carrying capacity and increasing ecological footprint. The 'inclusion', for bringing more and more people in the purview of development is often limited to social and economic inclusion rather than spatial and ecological inclusion. Economic investment decisions are also not always supported with spatial planning decisions. Most planning for a sustainable <span class="hlt">Earth</span>, be at a level of rural settlement, city, region, national or Global, fail on the capacity and capability fronts. In India, for example, out of some 8,000 towns and cities, Master Plans exist for only about 1,800. A chapter on sustainability or environment is neither statutorily compulsory nor a norm for these Master Plans. Geospatial technologies including Remote Sensing, GIS, Indian National Spatial Data Infrastructure (NSDI), Indian National Urban Information Systems (NUIS), Indian Environmental Information System (ENVIS), and Indian National GIS (NGIS), etc. have potential to map, analyse, visualize and take sustainable developmental decisions based on participatory social, economic and social inclusion. Sustainable <span class="hlt">Earth</span>, at all scales, is a logical and natural outcome of a digitally mapped, conceived and planned <span class="hlt">Earth</span>. Digital <span class="hlt">Earth</span>, in fact, itself offers a platform to dovetail the ecological, social and economic considerations in transforming it into a sustainable <span class="hlt">Earth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.785H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.785H"><span id="translatedtitle"><span class="hlt">Effects</span> of X-ray flares on the aeronomy of Mars: Simultaneous measurements of ionospheric <span class="hlt">effects</span> of X-ray flares on <span class="hlt">Earth</span> and Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haider, Syed A.; Machado Santos, Angela; Abdu, Mangalathayil A.; Batista, Inez S.; Shah, Siddhi Y.; Thirupathaiah, P.</p> <p>2016-07-01</p> <p>MIRI: Validation and Testing Requirements We have studied X-ray aeronomy in the ionospheric E region of Mars during six X-ray flares that occurred on 28 March and 6 April, 2001; 17,18 March and 21 April, 2003 and 19 February, 2005 respectively. These flares were responded by the corresponding electron density profiles of Mars Global Surveyor (MGS). The time series of photoionization rate, photoelectron impact ionization rate, photoelectron flux, ion density, electron density and total Electron Content (TEC) are predicted for each flare day. The estimated production rate, flux and densities are increased by 1-2 orders of magnitude due to <span class="hlt">effects</span> of these flares in the E region ionosphere of Mars. The normalized estimated TEC are compared with the normalized measured TEC of MGS profiles. At the peak flare time the normalized estimated and normalized measured TEC were enhanced by a factor of 5-10 and 2 respectively. The <span class="hlt">effects</span> of these flares were also registered in the D region equatorial ionosphere of <span class="hlt">Earth</span> at Fortaleza observatory. The flares of 6 April, 2001, 17 March and 21 April, 2003 also produced electron density enhancement in the E region ionosphere of <span class="hlt">Earth</span> at College AK and Cachoeira Paulista observatories. The minimum frequency fmin, recorded in ionogram, increased by 100% (due to D region absorption) while the foE increased by 20%, in the <span class="hlt">Earth</span>'s ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=fields+AND+ice&pg=6&id=EJ469516','ERIC'); return false;" href="http://eric.ed.gov/?q=fields+AND+ice&pg=6&id=EJ469516"><span id="translatedtitle">Think <span class="hlt">Earth</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Niedermeyer, Fred; Ice, Kay</p> <p>1992-01-01</p> <p>Describes a series of environmental education instructional units for grades K-6 developed by the Think <span class="hlt">Earth</span> Consortium that cover topics such as conservation, pollution control, and waste reduction. Provides testimony from one sixth-grade teacher that field tested the second-grade unit. (MDH)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70046547','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70046547"><span id="translatedtitle">Rare <span class="hlt">earths</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gambogi, J.</p> <p>2013-01-01</p> <p>Global mine production of rare <span class="hlt">earths</span> was estimated to have declined slightly in 2012 relative to 2011 (Fig. 1). Production in China was estimated to have decreased to 95 from 105 kt (104,700 from 115,700 st) in 2011, while new mine production in the United States and Australia increased.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030011385&hterms=physiology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D40%26Ntt%3Dphysiology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030011385&hterms=physiology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D40%26Ntt%3Dphysiology"><span id="translatedtitle">The <span class="hlt">Effect</span> of Microgravity on the Smallest Space Travelers: Bacterial Physiology and Virulence on <span class="hlt">Earth</span> and in Microgravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pyle, Barry; Vasques, Marilyn; Aquilina, Rudy (Technical Monitor)</p> <p>2002-01-01</p> <p>Since the first human flights outside of <span class="hlt">Earth</span>'s gravity, crew health and well-being have been major concerns. Exposure to microgravity during spaceflight is known to affect the human immune response, possibly making the crew members more vulnerable to infectious disease. In addition, biological experiments previously flown in space have shown that bacteria grow faster in microgravity than they do on <span class="hlt">Earth</span>. The ability of certain antibiotics to control bacterial infections may also differ greatly in microgravity. It is therefore critical to understand how spaceflight and microgravity affect bacterial virulence, which is their ability to cause disease. By utilizing spaceflight hardware provided by the European Space Agency (ESA), Dr. Barry Pyle and his team at Montana State University, Bozeman, will be performing an experiment to study the <span class="hlt">effects</span> of microgravity on the virulence of a common soil and water bacterium, Pseudomonas aeruginosa. Importantly, these bacteria have been detected in the water supplies of previous Space Shuttle flights. The experiment will examine the <span class="hlt">effects</span> of microgravity exposure on bacterial growth and on the bacterium's ability to form a toxin called Exotoxin A. Another goal is to evaluate the <span class="hlt">effects</span> of microgravity on the physiology of the bacteria by analyzing their ability to respire (produce energy), by studying the condition of the plasma membrane surrounding the cell, and by determining if specific enzymes remain active. Proteins produced by the bacteria will also be assayed to see if the normal functions of the bacteria are affected. In the context of human life support in spaceflight, the results of this experiment will offer guidance in providing the highest possible water quality for the Shuttle in order to limit the risk of infection to human occupants and to minimize water system and spacecraft deterioration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22443532','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22443532"><span id="translatedtitle">Origin of “memory glass” <span class="hlt">effect</span> in pressure-amorphized rare-<span class="hlt">earth</span> molybdate single crystals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Willinger, Elena; Sinitsyn, Vitaly; Khasanov, Salavat; Redkin, Boris; Shmurak, Semeon; Ponyatovsky, Eugeny</p> <p>2015-02-15</p> <p>The memory glass <span class="hlt">effect</span> (MGE) describes the ability of some materials to recover the initial structure and crystallographic orientation after pressure-induced amorphization (PIA). In spite of numerous studies the nature and underlying mechanisms of this phenomenon are still not clear. Here we report investigations of MGE in β′-Eu{sub 2}(MoO{sub 4}){sub 3} single crystal samples subjected to high pressure amorphization. Using the XRD and TEM techniques we carried out detailed analysis of the structural state of high pressure treated single crystal samples as well as structural transformations due to subsequent annealing at atmospheric pressure. The structure of the sample has been found to be complex, mainly amorphous, however, the amorphous medium contains evenly distributed nanosize inclusions of a paracrystalline phase. The inclusions are highly correlated in orientation and act as “memory units” in the MGE. - Graphical abstract: Schematic representation of pressure-induced amorphization and “memory glass” <span class="hlt">effect</span> in rare-<span class="hlt">earth</span> molybdate single crystals. The XRD and TEM measurements have revealed the presence of the residual identically oriented paracrystalline nanodomains in the pressure-amorphized state. These domains preserve the information about initial structure and orientation of the sample. They act as memory units and crystalline seeds during transformation of the amorphous phase back to the starting single crystalline one. - Highlights: • Pressure-amorphized Eu{sub 2}(MoO4){sub 3} single crystals were studied ex-situ by XRD and TEM. • Tiny residual crystalline inclusions were found in amorphous matrix of sample. • The inclusions keep in memory the parent crystal structure and orientation. • The inclusions account for “memory glass” <span class="hlt">effect</span> in rare-<span class="hlt">earth</span> molibdates.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JAP...100b4506W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JAP...100b4506W"><span id="translatedtitle"><span class="hlt">Effect</span> of exciplex formation on organic light emitting diodes based on rare-<span class="hlt">earth</span> complex</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, D. Y.; Li, W. L.; Chu, B.; Liang, C. J.; Hong, Z. R.; Li, M. T.; Wei, H. Z.; Xin, Q.; Niu, J. H.; Xu, J. B.</p> <p>2006-07-01</p> <p>An exciplex can be formed due to the charge transfer between the lowest unoccupied molecular orbital (LUMO) of the acceptor and the highest occupied molecular orbital (HOMO) of the donor. By introducing a mixing layer composed of [N ,N'-diphenyl-N ,N'bis (3-methylphenyl)-1,1'-diphenyl-4,4'-diamine] (TPD) and europium(dibenzoylmethanato)3(bathophenanthroline) [Eu(DBM)3bath] and a graded interface, elimination of light emission from the exciplex and significant luminescence enhancement of trivalent europium ions (Eu3+) in organic light emitting devices have been achieved. The elimination mechanism of exciplex emission based on the concept that an exciplex can be formed between LUMO of the acceptor (Eu complex) and HOMO of donor (TPD) was investigated. To comprehensively understand the mechanism, devices consisting of a Eu(DBM)3bath as the emitting material and the devices using other rare-<span class="hlt">earth</span> (RE) complex [RE(DBM)3bath] as the emitting material were fabricated with the same device configuration. As a reference, four spin-coated films with the blend composed of TPD and the gadolinium complex [Gd(DBM)3bath] were also fabricated. The electroluminescence (EL) spectra from the devices and photoluminescence spectra from the spin-coating films were fully investigated. The results show that the exciplex was formed by the charge transfer from the donor TPD to the acceptor RE complex, the exciplex state that acted as a transient excited state can be controlled by altering the molecular ratio in the mixing films. The relation of the exciplex formation based on EL devices with the RE complex versus the variety of the RE ions is also discussed by manipulating the energy level of the excited state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B33F..06B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B33F..06B"><span id="translatedtitle">Cooling biogeophysical <span class="hlt">effect</span> of large-scale tropical deforestation in three <span class="hlt">Earth</span> System models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brovkin, V.; Pugh, T.; Robertson, E.; Bathiany, S.; Jones, C.; Arneth, A.</p> <p>2015-12-01</p> <p>Vegetation cover in the tropics is limited by moisture availability. Since transpiration from forests is generally greater than from grasslands, the sensitivity of precipitation in the Amazon to large-scale deforestation has long been seen as a critical parameter of climate-vegetation interactions. Most Amazon deforestation experiments to date have been performed with interactive land-atmosphere models but prescribed sea surface temperatures (SSTs). They reveal a strong reduction in evapotranspiration and precipitation, and an increase in global air surface temperature due to reduced latent heat flux. We performed large-scale tropical deforestation experiments with three <span class="hlt">Earth</span> system models (ESMs) including interactive ocean models, which participated in the FP7 project EMBRACE. In response to tropical deforestation, all models simulate a significant reduction in tropical precipitation, similar to the experiments with prescribed SSTs. However, all three models suggest that the response of global temperature to the deforestation is a cooling or no change, differing from the result of a global warming in prescribed SSTs runs. Presumably, changes in the hydrological cycle and in the water vapor feedback due to deforestation operate in the direction of a global cooling. In addition, one of the models simulates a local cooling over the deforested tropical region. This is opposite to the local warming in the other models. This suggests that the balance between warming due to latent heat flux decrease and cooling due to albedo increase is rather subtle and model-dependent. Last but not least, we suggest using large-scale deforestation as a standard biogeophysical experiment for model intercomparison within the CMIP6 framework.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988PhRvB..37.7663N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988PhRvB..37.7663N"><span id="translatedtitle">Coulomb correlation <span class="hlt">effects</span> in the quasiparticle band structure of ferromagnetic rare-<span class="hlt">earth</span> insulators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nolting, W.; Borgiel, W.; Borstel, G.</p> <p>1988-05-01</p> <p>We present a method for calculating the temperature dependence of the electronic quasiparticle density of states (QDOS) of a ferromagnetic rare-<span class="hlt">earth</span> insulator like EuO. Special attention is devoted to how the ``localized'' ferromagnetism manifests itself in x-ray photoemission and bremsstrahlung isochromat spectra. Our study includes the first six conduction bands of EuO (the first five are Eu 5d like, the sixth is mainly of Eu 6s character) as well as the rather flat 4f levels. The starting point is an extended d-f exchange model, the main parts of which are an exchange interaction between 4f moments and conduction electrons, a Coulomb repulsion between highly correlated 4f electrons, and a hybridization of 4f with conduction-band states. We use an exact T=0 relationship between spin-up quasiparticle energies and one-electron Bloch energies ɛm(k) for an optimal determination of the latter by performing a self-consistent, spin-polarized band-structure calculation based on density-functional theory. For finite temperatures the model is approximately solved by a many-body procedure. The QDOS exhibits a striking temperature dependence mainly due to the d-f exchange. Two 4f-like peaks appear in the spin-polarized QDOS, the low-energy one being occupied, the high-energy one being empty. The temperature dependence of the localized ferromagnetism appears in the QDOS as a temperature-dependent shift of spectral weight between the low- and the high-energy peak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090026971&hterms=pe&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpe','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090026971&hterms=pe&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpe"><span id="translatedtitle">Radiation Protection <span class="hlt">Effectiveness</span> of Polymeric Based Shielding Materials at Low <span class="hlt">Earth</span> Orbit</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Badavi, Francis F.; Stewart-Sloan, Charlotte R.; Wilson, John W.; Adams, Daniel O.</p> <p>2008-01-01</p> <p>Correlations of limited ionizing radiation measurements onboard the Space Transportation System (STS; shuttle) and the International Space Station (ISS) with numerical simulations of charged particle transport through spacecraft structure have indicated that usage of hydrogen rich polymeric materials improves the radiation shielding performance of space structures as compared to the traditionally used aluminum alloys. We discuss herein the radiation shielding correlations between measurements on board STS-81 (Atlantis, 1997) using four polyethylene (PE) spheres of varying radii, and STS-89 (Endeavour, 1998) using aluminum alloy spheres; with numerical simulations of charged particle transport using the Langley Research Center (LaRC)-developed High charge (Z) and Energy TRaNsport (HZETRN) algorithm. In the simulations, the Galactic Cosmic Ray (GCR) component of the ionizing radiation environment at Low <span class="hlt">Earth</span> Orbit (LEO) covering ions in the 1< or equals Z< or equals 28 range is represented by O'Neill's (2004) model. To compute the transmission coefficient for GCR ions at LEO, O'Neill's model is coupled with the angular dependent LaRC cutoff model. The trapped protons/electrons component of LEO environment is represented by a LaRC-developed time dependent procedure which couples the AP8min/AP8max, Deep River Neutron Monitor (DRNM) and F10.7 solar radio frequency measurements. The albedo neutron environment resulting from interaction of GCR ions with upper atmosphere is modeled through extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. With the validity of numerical simulations through correlation with PE and aluminum spheres measurements established, we further present results from the expansion of the simulations through the selection of high hydrogen content commercially available polymeric constituents such as PE foam core and Spectra fiber(Registered TradeMark) composite face sheet to assess their radiation shield properties as compared to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvB..91x5116V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvB..91x5116V"><span id="translatedtitle">Electronic correlations in Fe at <span class="hlt">Earth</span>'s inner core conditions: <span class="hlt">Effects</span> of alloying with Ni</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vekilova, O. Yu.; Pourovskii, L. V.; Abrikosov, I. A.; Simak, S. I.</p> <p>2015-06-01</p> <p>We have studied the body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal close-packed (hcp) phases of Fe alloyed with 25 at.% of Ni at <span class="hlt">Earth</span>'s core conditions using an ab initio local density approximation + dynamical mean-field theory approach. The alloys have been modeled by ordered crystal structures based on the bcc, fcc, and hcp unit cells with the minimum possible cell size allowing for the proper composition. Our calculations demonstrate that the strength of electronic correlations on the Fe 3 d shell is highly sensitive to the phase and local environment. In the bcc phase, the 3 d electrons at the Fe site with Fe only nearest neighbors remain rather strongly correlated, even at extreme pressure-temperature conditions, with the local and uniform magnetic susceptibility exhibiting a Curie-Weiss-like temperature evolution and the quasiparticle lifetime Γ featuring a non-Fermi-liquid temperature dependence. In contrast, for the corresponding Fe site in the hcp phase, we predict a weakly correlated Fermi-liquid state with a temperature-independent local susceptibility and a quadratic temperature dependence of Γ. The iron sites with nickel atoms in the local environment exhibit behavior in the range between those two extreme cases, with the strength of correlations gradually increasing along the hcp-fcc-bcc sequence. Further, the intersite magnetic interactions in the bcc and hcp phases are also strongly affected by the presence of Ni nearest neighbors. The sensitivity to the local environment is related to modifications of the Fe partial density of states due to mixing with Ni 3 d states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.3417A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.3417A"><span id="translatedtitle"><span class="hlt">Earth</span> meandering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asadiyan, H.; Zamani, A.</p> <p>2009-04-01</p> <p>In this paper we try to put away current Global Tectonic Model to look the tectonic evolution of the <span class="hlt">earth</span> from new point of view. Our new dynamic model is based on study of river meandering (RM) which infer new concept as <span class="hlt">Earth</span> meandering(EM). In a universal gravitational field if we consider a clockwise spiral galaxy model rotate above Ninety East Ridge (geotectonic axis GA), this system with applying torsion field (likes geomagnetic field) in side direction from Rocky Mt. (west geotectonic pole WGP) to Tibetan plateau TP (east geotectonic pole EGP),it seems that pulled mass from WGP and pushed it in EGP due to it's rolling dynamics. According to this idea we see in topographic map that North America and Green land like a tongue pulled from Pacific mouth toward TP. Actually this system rolled or meander the <span class="hlt">earth</span> over itself fractaly from small scale to big scale and what we see in the river meandering and <span class="hlt">Earth</span> meandering are two faces of one coin. River transport water and sediments from high elevation to lower elevation and also in EM, mass transport from high altitude-Rocky Mt. to lower altitude Himalaya Mt. along 'S' shape geodetic line-optimum path which connect points from high altitude to lower altitude as kind of Euler Elastica(EE). These curves are responsible for mass spreading (source) and mass concentration (sink). In this regard, tiltness of <span class="hlt">earth</span> spin axis plays an important role, 'S' are part of sigmoidal shape which formed due to intersection of <span class="hlt">Earth</span> rolling with the <span class="hlt">Earth</span> glob and actual feature of transform fault and river meandering. Longitudinal profile in mature rivers as a part of 'S' curve also is a kind of EE. 'S' which bound the whole <span class="hlt">earth</span> is named S-1(S order 1) and cube corresponding to this which represent <span class="hlt">Earth</span> fracturing in global scale named C-1(cube order 1 or side vergence cube SVC), C-1 is a biggest cycle of spiral polygon, so it is not completely closed and it has separation about diameter of C-7. Inside SVC we introduce cone</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28009902','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28009902"><span id="translatedtitle">Ternary rare-<span class="hlt">earth</span> aluminium intermetallics RE10TAl3 (RE = Y, Ho, Tm, Lu; T = Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt) with an ordered anti-Co2Al5 structure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Benndorf, Christopher; Eckert, Hellmut; Janka, Oliver</p> <p>2017-01-24</p> <p>Twenty new rare-<span class="hlt">earth</span> metal rich intermetallic aluminium compounds, RE10TAl3 (RE = Y, Ho, Tm, Lu; T = Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt), were synthesized by arc melting the elements. The compounds crystallize, in analogy to e.g. the respective Cd representatives, with a ternary ordered structure as anti-type to the hexagonal Co2Al5 type, with the space group P63/mmc. The three crystallographically independent rare-<span class="hlt">earth</span> metal sites occupy the aluminium positions of the aristotype, while the transition metal and aluminium atoms are ordered on the two cobalt sites. Like other rare-<span class="hlt">earth</span> rich compounds the RE10TX3 members also exhibit transition-metal-centred T@RE6 trigonal prisms as striking structural building units. The prepared compounds have been investigated by susceptibility measurements and (27)Al solid-state MAS-NMR measurements conducted on the Pauli-paramagnetic Y and Lu compounds. Some compounds show a certain amount of disorder as seen from the single crystal structure analysis and from signal broadening in the NMR investigations. By separating Knight shifts from second-order <span class="hlt">quadrupolar</span> shifts via field dependent measurements, monotonic trends can be discerned regarding the <span class="hlt">effect</span> of the T atom valence electron concentration and period number, as well as the <span class="hlt">effect</span> of the closed 4f shell contributed in the Lu compounds. The results confirm that a comparison of Knight shifts within a series of isotypic compounds can reveal important electronic structure information in intermetallic systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA43A2356B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA43A2356B"><span id="translatedtitle"><span class="hlt">Effect</span> Of The Radiation Pressure On Planetary Exospheres: Analytical Approach And Application To <span class="hlt">Earth</span>, Mars and Hot Jupiters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I. S.; Mazelle, C. X.</p> <p>2015-12-01</p> <p>The atomic Hydrogen is one of the most abundant species in many planetary exospheres, such as on <span class="hlt">Earth</span>, on planets in the Solar System and on Hot Jupiters. Because the exosphere is a quasi-collisionless medium, the atomic Hydrogen can reach several planetary radii without collisions and its motion is only determined by external forces such as the gravity and the radiation pressure. However, the exosphere still remains a complex medium : 1) to model because, on one hand, this is a region of interaction between the interplanetary medium and the planetary atmosphere and, on another hand, the fluid approach is not appropriate and a kinetic should be used instead, 2) to observe because of the extremely low densities. Currently, the most used analytical model to determine the neutral density profiles is the well-known Chamberlain's one, which however includes only the gravity. We have developed an analytical model based on the previous work by Bishop and Chamberlain (1989) with a Hamiltonian approach, taking into account both the gravity and the radiation pressure. We extend their previous 1D model (density profiles on the Sun-planet axis only) into a 2D model depending on the distance from the planet and the zenith angle to derive density profiles (Beth et al. 2015b, in review). Moreover, we derived an analytical formula for the thermal escape to compare with the classical Jeans' escape flux. We thus show that the radiation pressure induces : Strong density asymmetries at high altitudes in the planetary exospheres, leading to the phenomenon of "geotail" at <span class="hlt">Earth</span>, Natural existence of an external limit (or exopause) for the exosphere, whose location is analytically determined, Increase of the exospheric densities compared with Chamberlain profiles without radiation pressure (e.g. up to +150% at 5 Martian radius), Significant increase of the thermal escape flux (up to 30/35% for <span class="hlt">Earth</span>/Mars today), until a "blow-off" regime with a constant escape flux for an extreme</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016P%26SS..129...13L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016P%26SS..129...13L"><span id="translatedtitle">Global <span class="hlt">effects</span> of transmitted shock wave propagation through the <span class="hlt">Earth</span>'s inner magnetosphere: First results from 3-D hybrid kinetic modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lipatov, A. S.; Sibeck, D. G.</p> <p>2016-09-01</p> <p>We use a new hybrid kinetic model to simulate the response of ring current, outer radiation belt, and plasmaspheric particle populations to impulsive interplanetary shocks. Since particle distributions attending the interplanetary shock waves and in the ring current and radiation belts are non-Maxwellian, wave-particle interactions play a crucial role in energy transport within the inner magnetosphere. Finite gyroradius <span class="hlt">effects</span> become important in mass loading the shock waves with the background plasma in the presence of higher energy ring current and radiation belt ions and electrons. Initial results show that shocks cause strong deformations in the global structure of the ring current, radiation belt, and plasmasphere. The ion velocity distribution functions at the shock front, in the ring current, and in the radiation belt help us determine energy transport through the <span class="hlt">Earth</span>'s inner magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820052841&hterms=attention&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dattention','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820052841&hterms=attention&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dattention"><span id="translatedtitle">The latitude dependence of the variance of zonally averaged quantities. [in polar meteorology with attention to geometrical <span class="hlt">effects</span> of <span class="hlt">earth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>North, G. R.; Bell, T. L.; Cahalan, R. F.; Moeng, F. J.</p> <p>1982-01-01</p> <p>Geometric characteristics of the spherical <span class="hlt">earth</span> are shown to be responsible for the increase of variance with latitude of zonally averaged meteorological statistics. An analytic model is constructed to display the <span class="hlt">effect</span> of a spherical geometry on zonal averages, employing a sphere labeled with radial unit vectors in a real, stochastic field expanded in complex spherical harmonics. The variance of a zonally averaged field is found to be expressible in terms of the spectrum of the vector field of the spherical harmonics. A maximum variance is then located at the poles, and the ratio of the variance to the zonally averaged grid-point variance, weighted by the cosine of the latitude, yields the zonal correlation typical of the latitude. An example is provided for the 500 mb level in the Northern Hemisphere compared to 15 years of data. Variance is determined to increase north of 60 deg latitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170002746&hterms=cause+effect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcause%2Beffect','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170002746&hterms=cause+effect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcause%2Beffect"><span id="translatedtitle">Global <span class="hlt">Effects</span> of Transmitted Shock Wave Propagation Through the <span class="hlt">Earth</span>'s Inner Magnetosphere: First Results from 3-D Hybrid Kinetic Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lipatov, A. S.; Sibeck, D. G.</p> <p>2016-01-01</p> <p>We use a new hybrid kinetic model to simulate the response of ring current, outer radiation belt, and plasmaspheric particle populations to impulsive interplanetary shocks. Since particle distributions attending the interplanetary shock waves and in the ring current and radiation belts are non-Maxwellian, waveparticle interactions play a crucial role in energy transport within the inner magnetosphere. Finite gyroradius <span class="hlt">effects</span> become important in mass loading the shock waves with the background plasma in the presence of higher energy ring current and radiation belt ions and electrons. Initial results show that shocks cause strong deformations in the global structure of the ring current, radiation belt, and plasmasphere. The ion velocity distribution functions at the shock front, in the ring current, and in the radiation belt help us determine energy transport through the <span class="hlt">Earth</span>'s inner magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1172201','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1172201"><span id="translatedtitle">DIORAMA <span class="hlt">Earth</span> Terrain Model</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Werley, Kenneth Alan</p> <p>2015-03-10</p> <p>When simulating near-surface nuclear detonations, the terrain of the <span class="hlt">Earth</span> can have an <span class="hlt">effect</span> on the observed outputs. The critical parameter is called the “height of burst”. In order to model the <span class="hlt">effect</span> of terrain on the simulations we have incorporated data from multiple sources to give 9 km resolution data with global coverage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3248S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3248S"><span id="translatedtitle">Numerical estimates of seismic <span class="hlt">effects</span> after collisions of small bodies with the <span class="hlt">Earth</span> atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Svetsov, Vladimir; Shuvalov, Valery</p> <p></p> <p>Small bodies - meteoroids, asteroids or cometary objects of moderate size (10 - 100 m) every so often do not survive the entry through the planetary atmosphere and release their energy at some altitudes. Then the aerial blast waves reach the ground and generate Rayleigh seismic surface waves. The magnitude of the following earthquake can be significant as in the cases of the Tunguska event of 30 June 1908 or the Chelyabinsk airburst of 15 February 2013. If the pressure on the ground is known as a function of coordinates and time, the energy of seismic waves can be calculated using a solution of Lamb’s problem of the response to vertical load acting on the surface of an elastic half-space. The numerical procedure includes calculations of pressure spectra and integrals which are proportional to the energy of seismic waves. The final formula for the calculation of earthquake magnitudes was calibrated using published results of measurements made during nuclear tests on Novaya Zemlya in 1961 - 1962. We carried out numerical simulations of the aerial shock waves in Chelyabinsk event of 15 February 2013, using hydrodynamic codes. The energy input along the atmospheric trajectory inclined at 19° to the <span class="hlt">Earth</span> surface was assumed to be proportional to the radiation intensity derived from numerous video records. The calculated magnitude of the seismic source proved to be 3.85 on the assumption that the initial kinetic energy of the asteroid was 300 kt TNT. For the energy of 500 kt TNT the magnitude was 4.0. These values are in agreement with the results of magnitude records within the measurement errors. We also calculated the magnitudes of earthquakes caused by spherical explosions with the energies from 30 kt to 30 Mt TNT (bodies from ~7 to 70 m in size) at altitudes from 5 to 45 km. The earthquake magnitude of the Chelyabinsk event corresponds to a spherical explosion at an altitude of about 35 km. For the Tunguska event of 1908, we obtained the earthquake magnitudes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhDT.......318S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhDT.......318S"><span id="translatedtitle">The <span class="hlt">effect</span> of an outdoor setting on the transfer of <span class="hlt">earth</span> science concepts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simmons, Jerry Marvin</p> <p></p> <p>The ability of students to transfer concepts learned in school to future learning and employment settings is critical to their academic and career success. Concept transfer can best be studied by defining it as a process rather than an isolated event. Preparation for future learning (PFL) is a process definition of transfer which recognizes the student's ability to draw from past experiences, make assumptions, and generate potential questions and strategies for problem resolution. The purpose of this study was to use the PFL definition of concept transfer to examine whether a knowledge-rich outdoor setting better prepares students for future learning of science concepts than the classroom setting alone does. The research hypothesis was that sixth-grade students experiencing a geology-rich outdoor setting would be better prepared to learn advanced <span class="hlt">earth</span> science concepts than students experiencing classroom learning only. A quasi-experimental research design was used for this study on two non-equivalent, self-contained sixth-grade rural public school classes. After a pretest was given on prior geology knowledge, the outdoor treatment group was taken on a geology-rich field excursion which introduced them to the concepts of mineral formation and mining. The indoor treatment group received exposure to the same concepts in the classroom setting via color slides and identification of mineral specimens. Subsequently, both groups received direct instruction on advanced concepts about mineral formation and mining. They were then given a posttest, which presented the students with a problem-solving scenario and questions related to concepts covered in the direct instruction. A t-test done on pretest data revealed that the indoor treatment group had previously learned classroom geology material significantly better than the outdoor treatment group had. Therefore an analysis of covariance was performed on posttest data which showed that the outdoor treatment group was better</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22391067','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22391067"><span id="translatedtitle">Application of resistivity monitoring to evaluate cement grouting <span class="hlt">effect</span> in <span class="hlt">earth</span> filled dam</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, Jin-Mo; Yoon, Wang-Jung</p> <p>2015-03-10</p> <p>In this paper, we applied electrical resistivity monitoring method to evaluate the cement grouting <span class="hlt">effect</span>. There are a lot of ways to evaluate cement grouting <span class="hlt">effect</span>. In order to do this evaluation in a great safety, high efficiency, and lower cost, resistivity monitoring is found to be the most appropriate technique. In this paper we have selected a dam site from Korea to acquire resistivity monitoring data and compare the results of inversion to estimate the cement grouting <span class="hlt">effect</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3152S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3152S"><span id="translatedtitle">Radioastronomical observations of the <span class="hlt">effect</span> of Lunar tidal wave in the upper atmosphere of the <span class="hlt">Earth</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sobitniak, Liubov; Ryabov, Mikhail</p> <p></p> <p>Since 1987 on the radio-telescope “URAN-4” monitoring of the fluxes of powerful galactic and extra-galactic radio sources at decameter waves have been held. On the basis of the monitoring data scans of radio sources were researched. The following <span class="hlt">effects</span> were detected: strong fluctuations, chart compression and disintegrated recording source. All these <span class="hlt">effects</span> can be caused by the passing of the tidal wave in the ionosphere, which acts like a "plasma" lens and distorts the wave front. There have been found <span class="hlt">effects</span> of forward and reverse tidal wave. The angular interval of tidal <span class="hlt">effects</span> are 60 degrees according to all researched space sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870055829&hterms=chalmers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dchalmers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870055829&hterms=chalmers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dchalmers"><span id="translatedtitle">The definition of the low <span class="hlt">earth</span> orbital environment and its <span class="hlt">effect</span> on thermal control materials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Durcanin, J. T.; Chalmers, D. R.; Visentine, J. T.</p> <p>1987-01-01</p> <p>The LEO environment and its <span class="hlt">effects</span> on thermal-control materials (TCMs) being evaluated for use in long-term-mission space structures such as the Space Station are characterized, summarizing the results of recent space and laboratory experiments. Factors examined include atomic oxygen (a serious problem out to 600-700 km), ionizing radiation, solar UV radiation, solid particles (manmade debris and micrometeoroids, a significant hazard out to about 1000 km), and synergistic <span class="hlt">effects</span>. Numerical data on the expected intensity of these <span class="hlt">effects</span> for the different Space Station components, the resistance of specific TCMs to the <span class="hlt">effects</span>, and the <span class="hlt">effectiveness</span> of protective coatings are compiled in extensive tables and illustrated with diagrams, graphs, and micrographs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.6255G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.6255G"><span id="translatedtitle">On The Possible Biological Nature of Climate Stability On <span class="hlt">Earth</span>: Implications From Study of Temperature Dependence of The Greenhouse <span class="hlt">Effect</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorshkov, V.; Makarieva, A.</p> <p></p> <p>Due to the exponential positive feedback between sea surface temperature and satu- rated water vapour concentration, the dependence of the planetary greenhouse <span class="hlt">effect</span> on atmospheric water content is critical for stability of a climate with extensive liq- uid hydrosphere. On the basis of the law of energy conservation we develop a simple physically transparent approach to description of radiative transfer in an atmosphere containing greenhouse substances. It is shown that the analytical solution of the equa- tion thus derived coincides with the exact solution of the well-known radiative transfer equation to the accuracy of 20% for all values of atmospheric optical depth. The de- rived equation makes it possible to easily take into account the non-radiative thermal fluxes (convection and latent heat) and obtain an analytical dependence of the green- house <span class="hlt">effect</span> on atmospheric concentrations of a set of greenhouse substances with arbitrary absorption intervals. The established dependence is used to analyse stabil- ity of the modern climate of <span class="hlt">Earth</span>. It is shown that the modern value of global mean surface temperature, which corresponds to the liquid state of the terrestrial hydro- sphere, is physically unstable. The observed stability of modern climate over geologi- cal timescales is therefore likely to be due to dynamic singularities in the temperature- dependent behaviour of the greenhouse <span class="hlt">effect</span>. We quantify these singularities from the empirical global data on greenhouse <span class="hlt">effect</span>. We hypothesise that such singulari- ties may appear due to controlling functioning of the natural global biota and discuss major arguments in support of this conclusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930006406','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930006406"><span id="translatedtitle">Simulation of the synergistic low <span class="hlt">Earth</span> orbit <span class="hlt">effects</span> of vacuum thermal cycling, vacuum UV radiation, and atomic oxygen</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dever, Joyce A.; Degroh, Kim K.; Stidham, Curtis R.; Stueber, Thomas J.; Dever, Therese M.; Rodriguez, Elvin; Terlep, Judith A.</p> <p>1992-01-01</p> <p>In order to assess the low <span class="hlt">Earth</span> orbit (LEO) durability of candidate space materials, it is necessary to use ground laboratory facilities which provide LEO environmental <span class="hlt">effects</span>. A facility combining vacuum thermal cycling and vacuum ultraviolet (VUV) radiation has been designed and constructed at NASA Lewis Research Center for this purpose. This facility can also be operated without the VUV lamps. An additional facility can be used to provide VUV exposure only. By utilizing these facilities, followed by atomic oxygen exposure in an RF plasma asher, the <span class="hlt">effects</span> of the individual vacuum thermal cycling and VUV environments can be compared to the <span class="hlt">effect</span> of the combined vacuum thermal cycling/VUV environment on the atomic oxygen durability of materials. The synergistic <span class="hlt">effects</span> of simulated LEO environmental conditions on materials were evaluated by first exposing materials to vacuum thermal cycling, VUV, and vacuum thermal cycling/VUV environments followed by exposure to atomic oxygen in an RP plasma asher. Candidate space power materials such as atomic oxygen protected polyimides and solar concentrator mirrors were evaluated using these facilities. Characteristics of the Vacuum Thermal Cycling/VUV Exposure Facility which simulates the temperature sequences and solar ultraviolet radiation exposure that would be experienced by a spacecraft surface in LEO are discussed. Results of durability evaluations of some candidate space power materials to the simulated LEO environmental conditions will also be discussed. Such results have indicated that for some materials, atomic oxygen durability is affected by previous exposure to thermal cycling and/or VUV exposure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22310647','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22310647"><span id="translatedtitle">Enhanced optical limiting <span class="hlt">effects</span> in a double-decker bis(phthalocyaninato) rare <span class="hlt">earth</span> complex using radially polarized beams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wu, Jia-Lu; Gu, Bing Liu, Dahui; Cui, Yiping; Sheng, Ning</p> <p>2014-10-27</p> <p>Optical limiting (OL) <span class="hlt">effects</span> can be enhanced by exploiting various limiting mechanisms and by designing nonlinear optical materials. In this work, we present the large enhancement of OL <span class="hlt">effects</span> by manipulating the polarization distribution of the light field. Theoretically, we develop the Z-scan and nonlinear transmission theories on a two-photon absorber under the excitation of cylindrical vector beams. It is shown that both the sensitivity of Z-scan technique and the OL <span class="hlt">effect</span> using radially polarized beams have the large enhancement compared with that using linearly polarized beams (LPBs). Experimentally, we investigate the nonlinear absorption properties of a double-decker Pr[Pc(OC{sub 8}H{sub 17}){sub 8}]{sub 2} rare <span class="hlt">earth</span> complex by performing Z-scan measurements with femtosecond-pulsed radially polarized beams at 800 nm wavelength. The observed two-photon absorption process, which originates from strong intramolecular π–π interaction, is exploited for OL application. The results demonstrate the large enhancement of OL <span class="hlt">effects</span> using radially polarized beams instead of LPBs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17066829','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17066829"><span id="translatedtitle">Influence of instar and commodity on insecticidal <span class="hlt">effect</span> of two diatomaceous <span class="hlt">earth</span> formulations against larvae of Ephestia kuehniella (Lepidoptera: Pyralidae).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Athanassiou, Christos G</p> <p>2006-10-01</p> <p>Laboratory experiments were carried out to evaluate the insecticidal <span class="hlt">effect</span> of two diatomaceous <span class="hlt">earth</span> (DE) formulations, SilicoSec and PyriSec, against larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Three instars were tested: first, third and fifth. The test was conducted in six commodities: barley Hordeum vulgare (L.) (Gramminae), rye Secale cereale L. (Gramminae), wheat Triticum sp. (Gramminae), wheat + 10% cracked wheat, wheat + 30% cracked wheat, and wheat flour. Quantities of these commodities were treated with the DEs at three dose rates: 250, 500, and 1000 ppm. Mortality of the exposed larvae on the DE-treated commodities was measured after 7 d of exposure. For both Des, mortality increased with dose, but this increase was lower when dose was increased from 500 to 1,000 ppm. The type of the commodity significantly affected DE <span class="hlt">effectiveness</span>. Both DEs were equally <span class="hlt">effective</span> on barley, rye, and wheat, whereas the presence of cracked wheat reduced larval mortality. In addition, significantly fewer larvae were dead on treated flour compared with the other five commodities. The increase of larval age significantly affected DE <span class="hlt">effectiveness</span>. First instars were very susceptible to both DEs, and mortality with 1,000 ppm exceeded 86%. In contrast, fifth instar were the least susceptible to DEs, because mortality with 1000 ppm was < 22%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH31C..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH31C..01P"><span id="translatedtitle">The Hohmann-Parker <span class="hlt">Effect</span> and its Consequences Measured by the Mars Science Laboratory on the Transfer from <span class="hlt">Earth</span> to Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Posner, A.; Odstrcil, D.; MacNeice, P. J.; Rastaetter, L.; Zeitlin, C. J.; Elliott, H. A.; Frahm, R. A.; Hayes, J. J.; von Rosenvinge, T. T.; Christian, E. R.; Andrews, J.; Brinza, D.; Epperly, M. E.; Neal, K.; Seimetz, L.; Smith, K. D.; Tyler, Y.; Weigle, E.</p> <p>2013-12-01</p> <p>We show that a spacecraft launched from <span class="hlt">Earth</span> towards Mars following a Hohmann minimum energy transfer trajectory has a strong tendency to remain well-connected magnetically to <span class="hlt">Earth</span>, in the early phase of the transfer, or to Mars in the late phase, via the Parker spiral magnetic field. On the return trip, the spacecraft would remain reasonably well-connected first to Mars and later to <span class="hlt">Earth</span>. Moreover, good magnetic connectivity occurs on all Hohmann transfers between neighboring planets in the inner solar system out to Mars. We call this hitherto unnamed circumstance the Hohmann-Parker <span class="hlt">effect</span>. We show consequences of the <span class="hlt">effect</span> by means of simultaneous cosmic radiation proxy observations made near <span class="hlt">Earth</span>, near Mars, and at the Mars Science Laboratory on the transfer from <span class="hlt">Earth</span> to Mars in 2011/2012. We support the observations with simulations of the large-scale magnetic field of the inner heliosphere during this period and compare the results with our predictions. The implications of the Hohmann-Parker <span class="hlt">effect</span> are discussed. MSL RAD Science Team: R. Beaujean, S. Boettcher, M. Bullock, S. Burmeister, F. A. Cucinotta, B. Ehresmann, D. Grinspoon, J. Guo, D. M. Hassler, M.-H. Kim, J. Koehler, O. Kortmann, C. Martin-Garcia, S. C. R. Rafkin, G. Reitz, and R. F. Wimmer-Schweingruber SOHO EPHIN Science Team: B. Heber, R. Mueller-Mellin</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...592A.118M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...592A.118M"><span id="translatedtitle">Superposed epoch study of ICME sub-structures near <span class="hlt">Earth</span> and their <span class="hlt">effects</span> on Galactic cosmic rays</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masías-Meza, J. J.; Dasso, S.; Démoulin, P.; Rodriguez, L.; Janvier, M.</p> <p>2016-08-01</p> <p>Context. Interplanetary coronal mass ejections (ICMEs) are the interplanetary manifestations of solar eruptions. The overtaken solar wind forms a sheath of compressed plasma at the front of ICMEs. Magnetic clouds (MCs) are a subset of ICMEs with specific properties (e.g. the presence of a flux rope). When ICMEs pass near <span class="hlt">Earth</span>, ground observations indicate that the flux of Galactic cosmic rays (GCRs) decreases. Aims: The main aims of this paper are to find common plasma and magnetic properties of different ICME sub-structures and which ICME properties affect the flux of GCRs near <span class="hlt">Earth</span>. Methods: We used a superposed epoch method applied to a large set of ICMEs observed in situ by the spacecraft ACE, between 1998 and 2006. We also applied a superposed epoch analysis on GCRs time series observed with the McMurdo neutron monitors. Results: We find that slow MCs at 1 AU have on average more massive sheaths. We conclude that this is because they are more <span class="hlt">effectively</span> slowed down by drag during their travel from the Sun. Slow MCs also have a more symmetric magnetic field and sheaths expanding similarly as their following MC, while in contrast, fast MCs have an asymmetric magnetic profile and a sheath in compression. In all types of MCs, we find that the proton density and the temperature and the magnetic fluctuations can diffuse within the front of the MC due to 3D reconnection. Finally, we derive a quantitative model that describes the decrease in cosmic rays as a function of the amount of magnetic fluctuations and field strength. Conclusions: The obtained typical profiles of sheath, MC and GCR properties corresponding to slow, middle, and fast ICMEs, can be used for forecasting or modelling these events, and to better understand the transport of energetic particles in ICMEs. They are also useful for improving future operative space weather activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SolE....8..235B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SolE....8..235B"><span id="translatedtitle">The deep <span class="hlt">Earth</span> origin of the Iceland plume and its <span class="hlt">effects</span> on regional surface uplift and subsidence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barnett-Moore, Nicholas; Hassan, Rakib; Flament, Nicolas; Müller, Dietmar</p> <p>2017-02-01</p> <p>The present-day seismic structure of the mantle under the North Atlantic Ocean indicates that the Iceland hotspot represents the surface expression of a deep mantle plume, which is thought to have erupted in the North Atlantic domain during the Palaeocene. The spatial and temporal evolution of the plume since its eruption is still highly debated, and little is known about its deep mantle history. Here, we use palaeogeographically constrained global mantle flow models to investigate the evolution of deep <span class="hlt">Earth</span> flow beneath the North Atlantic since the Jurassic. The models show that over the last ˜ 100 Myr a remarkably stable pattern of convergent flow has prevailed in the lowermost mantle near the tip of the African Large Low-Shear Velocity Province (LLSVP), making it an ideal plume nucleation site. We extract model dynamic topography representative of a plume beneath the North Atlantic region since eruption at ˜ 60 Ma to present day and compare its evolution to available offshore geological and geophysical observations across the region. This comparison confirms that a widespread episode of Palaeocene transient uplift followed by early Eocene anomalous subsidence can be explained by the mantle-driven <span class="hlt">effects</span> of a plume head ˜ 2500 km in diameter, arriving beneath central eastern Greenland during the Palaeocene. The location of the model plume eruption beneath eastern Greenland is compatible with several previous models. The predicted dynamic topography is within a few hundred metres of Palaeocene anomalous subsidence derived from well data. This is to be expected given the current limitations involved in modelling the evolution of <span class="hlt">Earth</span>'s mantle flow in 3-D, particularly its interactions with the base of a heterogeneous lithosphere as well as short-wavelength advective upper mantle flow, not captured in the presented global models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19673470','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19673470"><span id="translatedtitle">14N and 81Br <span class="hlt">quadrupolar</span> nuclei as sensitive NMR Probes of n-alkyltrimethylammonium bromide crystal structures. An experimental and theoretical study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alonso, Bruno; Massiot, Dominique; Florian, Pierre; Paradies, Henrich H; Gaveau, Philippe; Mineva, Tzonka</p> <p>2009-09-03</p> <p>This is the first time a comprehensive study has been carried out on n-alkyltrimethylammonium bromide salts using (14)N and (81)Br solid state NMR, X-ray diffraction, and theoretical calculations. The investigation represents a necessary step toward further (14)N and (81)Br NMR characterization of the environment of cationic and anionic groups in materials, accounting for the amphiphilic properties of cationic surfactants. The NMR spectra of five C(x)H(2x+1)(CH(3))(3)N(+)Br(-) polycrystalline samples with different n-alkyl chain lengths (x = 1, 12, 14, 16, 18) were recorded and modeled. The (14)N and (81)Br <span class="hlt">quadrupolar</span> coupling interaction parameters (C(Q), eta(Q)) were also estimated from spectrum modeling and from computer simulation. The obtained results were discussed in depth making use of the experimental and reoptimized crystal structures. In the study, both (14)N and (81)Br nuclei were found to be sensitive probes for small structural variations. The parameters which influence the NMR properties the most are mobility, deviation of C-N-C bond angles from T(d) angles, and variations in r(N-Br) distances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820030308&hterms=peptide+bond+formation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dpeptide%2Bbond%2Bformation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820030308&hterms=peptide+bond+formation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dpeptide%2Bbond%2Bformation"><span id="translatedtitle"><span class="hlt">Effect</span> of polynucleotides on the dimerization of glycine. [abiological protein synthesis in primitive <span class="hlt">earth</span> conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mizutani, H.; Ponnamperuma, C.</p> <p>1981-01-01</p> <p>Results from experiments to determine the <span class="hlt">effect</span> of polynucleotides on abiological formation of peptide bonds are reported. The reaction between glycine molecules in an aqueous phase in the presence of a condensing agent was chosen as a model, with polyphosphates being selected as the condensing agent for biologically relevant peptide formation. Four types of polynucleotides were used: polygluanic acid (G), polyuridic acid (U), polyadenylic acid (A), and polycytidylic acid (C); the <span class="hlt">effects</span> of small anions, acetate, chloride, and phosphate, were also studied. Procedures are given, including concentrations, pH, and incubation time, and the type of amino acid analyzer. The diglycine yields were, in order of most to least: G, C, A, U, and are diagrammed as a function of time; rate of formation followed the same order of magnitude as the final yields. Anion presence displayed no discernible <span class="hlt">effect</span>. The results are taken to indicate that polynucleotides do have an <span class="hlt">effect</span> on the formation of peptide bonds, an <span class="hlt">effect</span> significant in the understanding of chemical evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160014691','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160014691"><span id="translatedtitle">Non-Targeted <span class="hlt">Effects</span> and LET: Considerations for <span class="hlt">Earth</span> and Space Research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sowa, Marianne B.</p> <p>2016-01-01</p> <p>It is evident from reports in the literature that there are many confounding factors that are capable of modulating radiation-induced non-targeted responses such as the bystander <span class="hlt">effect</span> and the adaptive response. It has even been suggested that the observation of non-targeted responses may not be universally observable for differing radiation qualities. Dr. William Morgan made many contributions to the study of radiation induced non-targeted <span class="hlt">effects</span> and it is indeed this area of research where we first began our collaboration more than a decade ago. In this presentation, I will discuss elements of this journey together with a particular emphasis on the role of LET in non-targeted <span class="hlt">effects</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8344E..0XK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8344E..0XK"><span id="translatedtitle"><span class="hlt">Effect</span> of rare <span class="hlt">earth</span> elements (Er, Ho) on semi-metallic materials (ScN) in an applied electric field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Hyunjung; Park, Yeonjoon; King, Glen C.; Lee, Kunik; Choi, Sang H.</p> <p>2012-04-01</p> <p>The development of materials and fabrication technology for field-controlled spectrally active optics is essential for applications such as membrane optics, filters for LIDARs, windows for sensors, telescopes, spectroscopes, cameras and flat-panel displays. The dopants of rare <span class="hlt">earth</span> elements, in a host of optical systems, create a number of absorption and emission band structures and can easily be incorporated into many high quality crystalline and amorphous hosts. In wide band-gap semiconductors like ScN, the existing deep levels can capture or emit the mobile charges, and can be ionized with the loss or capture of the carriers which are the fundamental basis of concept for smart optic materials. The band gap shrinkage or splitting with dopants supports the possibility of this concept. In the present work, a semi-metallic material (ScN) was doped with rare <span class="hlt">earth</span> elements (Er, Ho) and tested under an applied electric field to characterize spectral and refractive index shifts by either Stark or Zeeman <span class="hlt">Effect</span>. These <span class="hlt">effects</span> can be verified using the UV-Vis spectroscopy, the Hall <span class="hlt">Effect</span> measurement and the ellipsometric spectroscopy. The optical band gaps of ScN doped with Er and doped with Ho were experimentally estimated as 2.33eV and 2.24eV (+/-0.2eV) respectively. This is less than that of undoped ScN (2.5+/-0.2eV). The red-shifted absorption onset is a direct evidence for the decrease of band gap energy (Eg), and the broadening of valence band states is attributable to the doping cases. A decrease in refractive index with an applied field was observed as a small shift in absorption coefficient using a variable angle spectroscopic ellipsometer. In the presence of an electric field, mobile carriers are redistributed within the space charge region (SCR) to produce this electro-refractive <span class="hlt">effect</span>. The shift in refractive index is also affected by the density and location of deep potential wells within the SCR. In addition, the microstructure change was observed by a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120003423','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120003423"><span id="translatedtitle"><span class="hlt">Effect</span> of Rare <span class="hlt">Earth</span> Elements (Er, Ho) on Semi-Metallic Materials (ScN) in an Applied Electric Field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kim, Hyunjung; Park, Yeonjoon; King, Glen C.; Lee, Kunik; Choi, Sang H.</p> <p>2012-01-01</p> <p>The development of materials and fabrication technology for field-controlled spectrally active optics is essential for applications such as membrane optics, filters for LIDARs, windows for sensors, telescopes, spectroscopes, cameras and flat-panel displays. The dopants of rare <span class="hlt">earth</span> elements, in a host of optical systems, create a number of absorption and emission band structures and can easily be incorporated into many high quality crystalline and amorphous hosts. In wide band-gap semiconductors like ScN, the existing deep levels can capture or emit the mobile charges, and can be ionized with the loss or capture of the carriers which are the fundamental basis of concept for smart optic materials. The band gap shrinkage or splitting with dopants supports the possibility of this concept. In the present work, a semi-metallic material (ScN) was doped with rare <span class="hlt">earth</span> elements (Er, Ho) and tested under an applied electric field to characterize spectral and refractive index shifts by either Stark or Zeeman <span class="hlt">Effect</span>. These <span class="hlt">effects</span> can be verified using the UV-Vis spectroscopy, the Hall <span class="hlt">Effect</span> measurement and the ellipsometric spectroscopy. The optical band gaps of ScN doped with Er and doped with Ho were experimentally estimated as 2.33eV and 2.24eV ( 0.2eV) respectively. This is less than that of undoped ScN (2.5 0.2eV). The red-shifted absorption onset is a direct evidence for the decrease of band gap energy (Eg), and the broadening of valence band states is attributable to the doping cases. A decrease in refractive index with an applied field was observed as a small shift in absorption coefficient using a variable angle spectroscopic ellipsometer. In the presence of an electric field, mobile carriers are redistributed within the space charge region (SCR) to produce this electro-refractive <span class="hlt">effect</span>. The shift in refractive index is also affected by the density and location of deep potential wells within the SCR. In addition, the microstructure change was observed by a TEM</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22939896','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22939896"><span id="translatedtitle">Synergetic <span class="hlt">effect</span> of alkaline <span class="hlt">earth</span> metal oxides and iron oxides on the degradation of hexachlorobenzene and its degradation pathway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Su, Guijin; Liu, Yexuan; Huang, Linyan; Shi, Yali; Zhang, Aiqian; Zhang, Lixia; Liu, Wenbin; Gao, Lirong; Zheng, Minghui</p> <p>2013-01-01</p> <p>The degradation of hexachlorobenzene (HCB) was carried out over physical mixtures of a series of alkaline <span class="hlt">earth</span> metal oxides (MO: M=Mg, Ca, Sr, Ba) and iron oxides with different crystal types (Fe(x)O(y):Fe(2)O(3) or Fe(3)O(4)) at 300°C. These physical mixtures all showed a synergetic <span class="hlt">effect</span> toward the degradation of HCB. A range of degradation products were identified by various methods, including tri- to penta-chlorobenzenes by gas chromatography/mass spectrometry (GC-MS), tri- to penta-chlorophenols, tetrachlorocatechol (TCC) and tetrachlorohydroquinone (TCHQ) by GC-MS after derivatization, and formic and acetic acids by ion chromatography. Two degradation pathways, hydrodechlorination and oxidative degradation, appear to occur competitively. However, more sequential chlorinated benzene and phenol congeners were formed over mixed MO/Fe(3)O(4) than over mixed MO/Fe(2)O(3) under the same conditions. The oxidative reaction dominated over mixed MO/Fe(2)O(3) and was promoted as the major reaction by the synergetic <span class="hlt">effect</span>, while both the oxidative and hydrodechlorination reactions were important over mixed MO/Fe(3)O(4), and both pathways are remarkably promoted by the synergetic <span class="hlt">effect</span>. The enhanced hydrodechlorination may be attributed to free electrons generated by the transformation of Fe(3)O(4) into Fe(2)O(3), and hydrogen provided by water adsorbed on the MO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT........15V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT........15V"><span id="translatedtitle">The <span class="hlt">effect</span> of gender on the attitudes of undergraduates toward young-<span class="hlt">earth</span> creationism after enrollment in an origins course</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinaja, Sean Stephen</p> <p></p> <p>Many Christian students graduate from secondary schools and enter Christian colleges with worldviews that are unbiblical or contain unbiblical components, many of which stem from their beliefs regarding origins. Little research has been done to study the <span class="hlt">effect</span> of gender on the role of a young-<span class="hlt">earth</span> creationist (YEC) origins course in shaping students' worldview. Research has shown that males and females respond differently to science and religion instruction; because the origins discussion is an intersection of science and religion, the study of gender's <span class="hlt">effect</span> in developing a Bible-based worldview is important so that Christian colleges might more <span class="hlt">effectively</span> guide their students in developing that biblical worldview. The purpose of this causal-comparative study was to determine whether students' gender affected their YEC worldview components after enrollment in a YEC origins course while controlling for their pre-course worldviews. A sample of 315 residential students enrolled in a YEC origins course at a conservative Christian college in the Southeast completed the Creationist Worldview Scale before and after taking the course; the survey also contained a demographic questionnaire that collected information regarding students' gender, major, classification, ethnicity, and secondary schooling. The data were analyzed using a one way ANCOVA. There were no statistically significant differences between male and female students' posttest age scores or posttest science scores, but there was a significant difference between their posttest theology scores. Suggestions for further research are also included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1571..744C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1571..744C"><span id="translatedtitle"><span class="hlt">Effect</span> of spent bleaching <span class="hlt">earth</span> based bio organic fertilizer on growth, yield and quality of eggplants under field condition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheong, K. Y.; Loh, S. K.; Salimon, J.</p> <p>2013-11-01</p> <p>Spent bleaching <span class="hlt">earth</span> (SBE) is a solid waste generated from the bleaching process in palm oil industry. This solid waste is currently disposed directly in landfills without treatment, causing severe water and air pollution. Recently, dumping of SBE in landfills or public disposal sites has been prohibited in most countries. Meanwhile, high costs associated with the large area of land needed for storage of the residue has lead to the interest in regenerate SBE. Thus, a recent novel approach has been carried out on the utilization of SBE in agriculture as an alternative method for disposal. In this study, a field experiment was conducted at an experimental plot in Plant House National University Malaysia to evaluate the <span class="hlt">effect</span> of SBE on the growth and quality of eggplant. Growth and quality parameters of eggplant including total fruit yield, total biomass, macronutrients concentration of leaf were studied through close monitoring and assessment. Field trials conducted showed that SBE is <span class="hlt">effective</span> in promoting eggplant growth and nutrient uptake compared to the control treatment under field conditions. Therefore, with the proper and <span class="hlt">effective</span> ways in handling SBE through conversion of SBE into beneficial bio organic fertilizer, this material which is a waste in the past will become an advantage in agriculture as a substitute for commercial fertilizers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5922263','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5922263"><span id="translatedtitle">Radiation <span class="hlt">effects</span> on spacecraft materials for Jupiter and near-<span class="hlt">earth</span> orbiters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bouquet, F.L.; Koprowski, K.F.</p> <p>1982-12-01</p> <p>An overview of radiation <span class="hlt">effects</span> on spacecraft materials is given in this paper. Specifically, the environment of the Jupiter Orbiting Spacecraft, Galileo, is treated along with analysis methods and simulated testing. Summaries of previous and present material test results are given. Preliminary results of surface erosion on insulation from a space shuttle experiment are summarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Rock+AND+Cycle&id=EJ675415','ERIC'); return false;" href="http://eric.ed.gov/?q=Rock+AND+Cycle&id=EJ675415"><span id="translatedtitle"><span class="hlt">Effect</span> of Knowledge Integration Activities on Students' Perception of the <span class="hlt">Earth</span>'s Crust as a Cyclic System.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kali, Yael; Orion, Nir; Eylon, Bat-Sheva</p> <p>2003-01-01</p> <p>Characterizes students' understanding of the rock cycle system. Examines <span class="hlt">effects</span> of a knowledge integration activity on their system thinking. Interprets answers to an open-ended test using a systems thinking continuum ranging from a completely static view of the system to an understanding of the system's cyclic nature. Reports meaningful…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090043183','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090043183"><span id="translatedtitle">Charged Particle Environments in <span class="hlt">Earth</span>'s Magnetosphere and their <span class="hlt">Effects</span> on Space System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Minow, Joseph I.</p> <p>2009-01-01</p> <p>This slide presentation reviews information on space radiation environments important to magnetospheric missions including trapped radiation, solar particle events, cosmic rays, and solar winds. It also includes information about ion penetration of the magnetosphere, galactic cosmic rays, solar particle environments, CRRES internal discharge monitor, surface charging and radiation <span class="hlt">effects</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4831107F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4831107F"><span id="translatedtitle">Detection of Yarkovsky <span class="hlt">effect</span> and solar radiation pressure on Near-<span class="hlt">Earth</span> Asteroids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faggioli, Laura; Del Vigna, Alessio; Milani, Andrea; Spoto, Federica; Valsecchi, Giovanni B.</p> <p>2016-10-01</p> <p>The orbit of small-sized asteroids can be affected by non-gravitational perturbations. When this happens, non-gravitational forces need to be taken into account since they are as important as collisions and gravitational perturbations for the overall understanding of the asteroid orbital evolution.The Yarkovsky <span class="hlt">effect</span> and the Solar Radiation Pressure (SRP) are non-gravitational perturbations that can be modelled knowing the physical properties of asteroids, and whose consequences of the motions can be measured from accurate astrometry.The knowledge of the physical properties of asteroids is usually not sufficient to produce the thermophysical models needed for the computation of the Yarkovsky acceleration. Nevertheless, it can often be measured as a semimajor axis drift if the astrometric dataset contains extremely accurate observations (e.g. radar data), or if the observations span a sufficiently long time interval.Farnocchia et al. 2013 list 21 NEAs with a measurable semimajor-axis drift. Since 2013, the number of asteroids for which it is possible to detect the Yarkovsky <span class="hlt">effect</span> has grown. This is due to the increased quality and time span of the observations, and to new radar measurements that have since become available. We are able to detect the Yarkovsky <span class="hlt">effect</span> for more than 40 NEAs, employing a high precision dynamical model, including the Newtonian attraction of 16 massive asteroids and the planetary relativistic terms, and a suitable astrometric data treatment. We present a list of objects with a significant detection of Yarkovksy <span class="hlt">effect</span> and a value compatible with the Yarkovsky mechanism.The computed non-gravitational perturbations will be added to the web portal of the ESA SSA-NEO Coordination Centre, highlighting the fact that the orbit has been computed taking the Yarkovsky <span class="hlt">effect</span> or the SRP into account. The inclusion of non-gravitational perturbations can also affect the results of the impact monitoring, as in the case of (410777) 2009 FD, (29075</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6644067','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6644067"><span id="translatedtitle">Signature <span class="hlt">effects</span> in some [ital N]=90 odd-[ital Z] rare-<span class="hlt">earth</span> nuclei</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rath, A.K.; Praharaj, C.R.; Khadkikar, S.B. Institute of Physics, Bhubaneswar 751005 )</p> <p>1993-05-01</p> <p>Using axially symmetric deformed configuration mixing and angular momentum projection techniques, we have studied the signature <span class="hlt">effects</span> in the [pi][ital h][sub 11/2] bands of [sup 147]La, [sup 149]Pr, and [sup 151]Pm nuclei. <span class="hlt">Effects</span> of rotation alignment on the signature splitting in energy and signature inversion in the [ital B]([ital E]2,[ital I][r arrow][ital I][minus]1) values are discussed. We find that transition from a strongly rotation-aligned limit to a weakly rotation-aligned (or more regular rotational behavior) regime or vice versa leads to signature inversion of the [ital B]([ital E]2) values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870035066&hterms=earth+nutation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearth%2Bnutation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870035066&hterms=earth+nutation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearth%2Bnutation"><span id="translatedtitle">The <span class="hlt">effects</span> of mantle and anelasticity on nutations, <span class="hlt">earth</span> tides, and tidal variations in rotation rate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wahr, John; Bergen, Zachary</p> <p>1986-01-01</p> <p>The paper models the <span class="hlt">effects</span> of mantle anelasticity on luni-solar nutations, on tidal deformation, on tidal variations in rotation rate, and on the eigenfrequency of the free core nutation. The results can be used to invert observations to solve for the anelastic contributions to the shear and bulk moduli of the upper and lower mantle. Specific anelastic models are used to numerically estimate the <span class="hlt">effects</span> of anelasticity on these geodetic observables. The nutation estimates are compared with observational results. Among the conclusions: (1) mantle anelasticity is likely to be the most important source of damping for the free core nutation; (2) present VLBI nutation results are, in principle, accurate enough to usefully bound anelasticity at diurnal periods. But the discrepancy between the VLBI observed nutations and the 1984 IAU nutation model cannot be explained by anelasticity and is not yet well enough understood to allow anelasticity to be determined from the data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860040631&hterms=Chandler+Wobble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DChandler%2BWobble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860040631&hterms=Chandler+Wobble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DChandler%2BWobble"><span id="translatedtitle">Modelling the pole tide and its <span class="hlt">effect</span> on the <span class="hlt">earth</span>'s rotation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carton, J. A.; Wahr, J. M.</p> <p>1986-01-01</p> <p>The pole tide is the response of the ocean to incremental centrifugal forces associated with the Chandler wobble. The tide has a potentially important <span class="hlt">effect</span> on the period and damping of the wobble, but it is at present not well constrained by observations. Here, both analytical and numerical models for the pole tide are constructed. The analytical models consider the tide first in a global ocean and then in an enclosed basin on a beta-plane. The results are found to approach equilibrium linearly with decreasing frequency and inversely with increasing basin depth. The numerical models solve Laplace's tidal equations over the world's oceans using realistic continental boundaries and bottom topography. The results indicate that the <span class="hlt">effects</span> of non-equilibrium portion of the deep ocean tide on the Chandler wobble period and damping are negligible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850050739&hterms=Infrared+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DInfrared%2Bradiation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850050739&hterms=Infrared+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DInfrared%2Bradiation"><span id="translatedtitle"><span class="hlt">Effects</span> of high altitude clouds on the <span class="hlt">earth</span>'s infrared radiation flux</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, W.-C.; Kaplan, L. D.</p> <p>1983-01-01</p> <p>Attention is given to the results of a study of cirrus cloud properties which employed the Goddard Laboratory for Atmospheric Sciences' general circulation model and concentrated on the <span class="hlt">effects</span> of the nonblackness of high clouds on the IR radiation flux. Although the thermal radiation flux is very sensitive to the treatment of cirrus optical properties in the IR, a more realistic assessment will depend on better parameterizations for cirrus cloud formation, persistence, and dissipation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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