MaRGEE: Move and Rotate Google Earth Elements

Science.gov (United States)

Dordevic, Mladen M.; Whitmeyer, Steven J.

2015-12-01

Google Earth is recognized as a highly effective visualization tool for geospatial information. However, there remain serious limitations that have hindered its acceptance as a tool for research and education in the geosciences. One significant limitation is the inability to translate or rotate geometrical elements on the Google Earth virtual globe. Here we present a new JavaScript web application to "Move and Rotate Google Earth Elements" (MaRGEE). MaRGEE includes tools to simplify, translate, and rotate elements, add intermediate steps to a transposition, and batch process multiple transpositions. The transposition algorithm uses spherical geometry calculations, such as the haversine formula, to accurately reposition groups of points, paths, and polygons on the Google Earth globe without distortion. Due to the imminent deprecation of the Google Earth API and browser plugin, MaRGEE uses a Google Maps interface to facilitate and illustrate the transpositions. However, the inherent spatial distortions that result from the Google Maps Web Mercator projection are not apparent once the transposed elements are saved as a KML file and opened in Google Earth. Potential applications of the MaRGEE toolkit include tectonic reconstructions, the movements of glaciers or thrust sheets, and time-based animations of other large- and small-scale geologic processes.

Variations of the Earth's rotation rate and cyclic processes in geodynamics

Directory of Open Access Journals (Sweden)

B.W. Levin

2017-05-01

Full Text Available The authors analyzed the relationship between variations of the Earth's rotation rate and the geodynamic processes within the Earth's body, including seismic activity. The rotation rate of a planet determines its uniaxial compression along the axis of rotation and the areas of various surface elements of the body. The Earth's ellipticity variations, caused naturally by the rotation rate variations, are manifested in vertical components of precise GPS measurements. Comparative analysis of these variations is considered in view of modern theoretical ideas concerning the Earth's figure. The results justify further research that is of interest for improvement of space systems and technologies.

Earth's Rotation: A Challenging Problem in Mathematics and Physics

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Ferrándiz, José M.; Navarro, Juan F.; Escapa, Alberto; Getino, Juan

2015-01-01

A suitable knowledge of the orientation and motion of the Earth in space is a common need in various fields. That knowledge has been ever necessary to carry out astronomical observations, but with the advent of the space age, it became essential for making observations of satellites and predicting and determining their orbits, and for observing the Earth from space as well. Given the relevant role it plays in Space Geodesy, Earth rotation is considered as one of the three pillars of Geodesy, the other two being geometry and gravity. Besides, research on Earth rotation has fostered advances in many fields, such as Mathematics, Astronomy and Geophysics, for centuries. One remarkable feature of the problem is in the extreme requirements of accuracy that must be fulfilled in the near future, about a millimetre on the tangent plane to the planet surface, roughly speaking. That challenges all of the theories that have been devised and used to-date; the paper makes a short review of some of the most relevant methods, which can be envisaged as milestones in Earth rotation research, emphasizing the Hamiltonian approach developed by the authors. Some contemporary problems are presented, as well as the main lines of future research prospected by the International Astronomical Union/International Association of Geodesy Joint Working Group on Theory of Earth Rotation, created in 2013.

Leeuwenhoek's "Proof" of the Earth's Rotation.

Science.gov (United States)

Kruglak, Haym; Johnson, Rand H.

1995-01-01

Leeuwenhoek's demonstration proving the Earth's rotation, which leads to some significant errors in reasoning, can be reproduced from this article and used to provide an interesting discussion in undergraduate astronomy and physics courses or clubs. (LZ)

Verifying the gravitational shift due to the earth's rotation

International Nuclear Information System (INIS)

Briatore, L.; Leschiutta, S.

1976-01-01

Data on various independent time scales kept in different laboratories are elaborated in order to verify the gravitational shift due to the earth's rotation. It is shown that the state of the art in the measurement of time is just now resulting in the possibility to make measurement of Δ t/t approximately 10 -13 . Moreover it is shown an experimental evidence of the earth's rotation relativistic effects

A survey of the theory of the Earth's rotation

Science.gov (United States)

Cannon, W. H.

1981-01-01

The theory of the Earth's rotation and the geophysical phenomena affecting it is examined. First principles are reviewed and the problem of polar motion and UT1 variations is formulated in considerable generality and detail. The effects of Earth deformations and the solid Earth tides are analyzed.

Regulating forest rotation to increase CO{sub 2} sequestration

Energy Technology Data Exchange (ETDEWEB)

Gong, P.; Kristroem, B.

1999-06-01

Previous studies have shown that the optimal forest rotation age increases considerably if the benefits of CO{sub 2} sequestration are included in rotation decisions. While these studies provide some guidelines for managing public forests, private forest owners may not choose the socially optimal rotation age. This paper discusses a regulation measure to increase CO{sub 2} sequestration in privately owned forests. The regulation problem is treated as a sequential game, where the regulator chooses a subsidy scheme and forest owners respond by changing rotation ages. A private forest owner receives a subsidy at the time of harvesting if he/she changes the rotation age towards the socially optimal one. The subsidy is proportional to the associated change in timber yield. The forest owner`s objective is to maximize the net present value of after-tax timber production profits and subsidies. The regulator`s decision problem is to find the subsidy rate that maximizes the net benefits of implementing the policy (the net of increased CO{sub 2} sequestration benefits, subsidy costs, and changes in forestry taxation income). Empirical results for Swedish examples show that the optimal subsidy rate is sensitive to the marginal benefit of CO{sub 2} sequestration, the social discount rate, and site quality. The optimal subsidy rate is found to be significantly lower than the marginal benefit of CO{sub 2} sequestration. With the proposed subsidy scheme, private forest owners will choose rotation ages longer than the Faustmann rotation, but significantly shorter than the socially optimal rotation age 21 refs, 6 tabs. Arbetsrapport 272

Long-Period Tidal Variations of the Earth's Rotation Rate

Science.gov (United States)

Desai, S.; Gross, R.; Wahr, J.

1999-01-01

Long-period tidal variations of the Earth's rotation rate are caused by the redistribution of mass associated with the respective elastic solid Earth tides, the ocean tide heights, and the anelasticity of the Earth's mantle, and by the relative angular momentum associated with the long-period ocean tide currents.

NATO Advanced Research Workshop on Earth Rotation : Solved and Unsolved Problems

CERN Document Server

1986-01-01

The idea for organl.zl.ng an Advanced Research Workshop entirely devoted to the Earth rotation was born in 1983 when Professor Raymond Hide suggested this topic to the special NATO panel of global transport mechanism in the Geosciences. Such a specialized meeting did not take place since the GEOP research conference on the rotation of the Earth and polar motion which was held at the Ohio State University (USA) in 1973. In the last ten years, highly precise measurements of the Earth's rotation parameters and new global geophysical data have become available allowing major advance to be made in the under­ standing of the various irregularities affecting the Earth's rotation. The aim of the workshop was to bring together scientists who have made important contributions in this field during the last decade both at the observational and geophysical interpretation levels. The confe­ rence was divided into four main topics. The first session was dedicated to the definition, implementation and maintenance of the te...

Aryabhala and Axial Rotation of Earth

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 3. Aryabhata and Axial Rotation of Earth - Khagola (The Celestial Sphere). Amartya Kumar Dutta. General Article Volume 11 Issue 3 March 2006 pp 51-68. Fulltext. Click here to view fulltext PDF. Permanent link:

Effects of Huge Earthquakes on Earth Rotation and the length of Day

Directory of Open Access Journals (Sweden)

Changyi Xu

2013-01-01

Full Text Available We calculated the co-seismic Earth rotation changes for several typical great earthquakes since 1960 based on Dahlen¡¦s analytical expression of Earth inertia moment change, the excitation functions of polar motion and, variation in the length of a day (ΔLOD. Then, we derived a mathematical relation between polar motion and earthquake parameters, to prove that the amplitude of polar motion is independent of longitude. Because the analytical expression of Dahlen¡¦s theory is useful to theoretically estimate rotation changes by earthquakes having different seismic parameters, we show results for polar motion and ΔLOD for various types of earthquakes in a comprehensive manner. The modeled results show that the seismic effect on the Earth¡¦s rotation decreases gradually with increased latitude if other parameters are unchanged. The Earth¡¦s rotational change is symmetrical for a 45° dip angle and the maximum changes appear at the equator and poles. Earthquakes at a medium dip angle and low latitudes produce large rotation changes. As an example, we calculate the polar motion and ΔLOD caused by the 2011 Tohoku-Oki Earthquake using two different fault models. Results show that a fine slip fault model is useful to compute co-seismic Earth rotation change. The obtained results indicate Dahlen¡¦s method gives good approximations for computation of co-seismic rotation changes, but there are some differences if one considers detailed fault slip distributions. Finally we analyze and discuss the co-seismic Earth rotation change signal using GRACE data, showing that such a signal is hard to be detected at present, but it might be detected under some conditions. Numerical results of this study will serve as a good indicator to check if satellite observations such as GRACE can detect a seismic rotation change when a great earthquake occur.

Earth rotation measured by lunar laser ranging

Science.gov (United States)

Stolz, A.; Bender, P. L.; Faller, J. E.; Silverberg, E. C.; Mulholland, J. D.; Shelus, P. J.; Williams, J. G.; Carter, W. E.; Currie, D. G.; Kaula, V. M.

1976-01-01

The estimated median accuracy of 194 single-day determinations of the earth's angular position in space is 0.7 millisecond (0.01 arc second). Comparison with classical astronomical results gives agreement to about the expected 2-millisecond uncertainty of the 5-day averages obtained by the Bureau International de l'Heure. Little evidence for very rapid variations in the earth's rotation is present in the data.

Aryabha~ and Axial Rotation of Earth

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. Aryabhata and Axial Rotation of Earth - Naksatra Dina (the Sidereal Day). Amartya Kumar Dutta. General Article Volume 11 Issue 4 April 2006 pp 56-74. Fulltext. Click here to view fulltext PDF. Permanent link:

The Goal of the IAU/IAG Joint Working Group on the Theory of Earth Rotation

Science.gov (United States)

Ferrandiz, J. M.; Gross, R. S.

2013-01-01

In 2012 the International Association of Geodesy (IAG) and the International Astronomical Union (IAU) initiated a process to establish a Joint Working Group (JWG) on theory of Earth rotation with the purpose of promoting the development of improved theories of the Earth rotation which reach the accuracy required to meet the needs of the near future as recommended by, e.g. GGOS, the Global Geodetic Observing System of the IAG. The JWG was approved by both organizations in April 2013 with the chairs being the two authors of this paper. Its structure comprises three Sub Working Groups (SWGs) addressing Precession/Nutation, Polar Motion and UT1, the Numerical Solutions and Validation, respectively. The SWGs should work in parallel for the sake of efficiency, but should keep consistency as an overall goal. This paper offers a view of the objectives and scope of the JWG and reports about its initial activities and plans.

Solar Rotational Periodicities and the Semiannual Variation in the Solar Wind, Radiation Belt, and Aurora

Science.gov (United States)

Emery, Barbara A.; Richardson, Ian G.; Evans, David S.; Rich, Frederick J.; Wilson, Gordon R.

2011-01-01

The behavior of a number of solar wind, radiation belt, auroral and geomagnetic parameters is examined during the recent extended solar minimum and previous solar cycles, covering the period from January 1972 to July 2010. This period includes most of the solar minimum between Cycles 23 and 24, which was more extended than recent solar minima, with historically low values of most of these parameters in 2009. Solar rotational periodicities from S to 27 days were found from daily averages over 81 days for the parameters. There were very strong 9-day periodicities in many variables in 2005 -2008, triggered by recurring corotating high-speed streams (HSS). All rotational amplitudes were relatively large in the descending and early minimum phases of the solar cycle, when HSS are the predominant solar wind structures. There were minima in the amplitudes of all solar rotational periodicities near the end of each solar minimum, as well as at the start of the reversal of the solar magnetic field polarity at solar maximum (approx.1980, approx.1990, and approx. 2001) when the occurrence frequency of HSS is relatively low. Semiannual equinoctial periodicities, which were relatively strong in the 1995-1997 solar minimum, were found to be primarily the result of the changing amplitudes of the 13.5- and 27-day periodicities, where 13.5-day amplitudes were better correlated with heliospheric daily observations and 27-day amplitudes correlated better with Earth-based daily observations. The equinoctial rotational amplitudes of the Earth-based parameters were probably enhanced by a combination of the Russell-McPherron effect and a reduction in the solar wind-magnetosphere coupling efficiency during solstices. The rotational amplitudes were cross-correlated with each other, where the 27 -day amplitudes showed some of the weakest cross-correlations. The rotational amplitudes of the > 2 MeV radiation belt electron number fluxes were progressively weaker from 27- to 5-day periods

Differential Rotation within the Earth's Outer Core

Science.gov (United States)

Hide, R.; Boggs, D. H.; Dickey, J. O.

1998-01-01

Non-steady differential rotation drive by bouyancy forces within the Earth's liquid outer core (OC) plays a key role not only in the generation of the main geomagnetic field by the magnetohydrodynamic (MHD) dynamo process but also in the excitation of irregular fluctuations in the angular speed of rotation of the overlying solid mantle, as evidenced by changes in the length of the day (LOD) on decadal and longer timescales (1-8).

The Impact of the Processing Batch Length in GNSS Data Analysis on the Estimates of Earth Rotation Parameters with Daily and Subdaily Time Resolution

Science.gov (United States)

Meindl, M.; Dach, R.; Thaller, D.; Schaer, S.; Beutler, G.; Jaeggi, A.

2012-04-01

Microwave observations from GNSS are traditionally analyzed in the post-processing mode using (solar) daily data batches. The 24-hour session length differs by only about four minutes from two revolution periods of a GPS satellite (corresponding to one sidereal day). The deep 2:1 resonance of the GPS revolution period with the length of the sidereal day may cause systematic effects in parameter estimates and spurious periodic signals in the resulting parameter time series. The selection of other (than daily) session lengths may help to identify systematic effects and to study their impact on GNSS-derived products. Such investigations are of great interest in a combined multi-GNSS analysis because of substantial differences in the satellites' revolution periods. Three years (2008-2010) of data from a global network of about 90 combined GPS/GLONASS receivers have been analyzed. Four different session lengths were used, namely the traditional 24 hours (UTC), two revolutions of a GLONASS satellite (16/17 sidereal days), two revolutions of a GPS satellite (one sidereal day), and a session length of 18/17 sidereal days, which does not correspond to either two GPS or two GLONASS revolution periods. GPS-only, GLONASS-only, and GPS/GLONASS-combined solution are established for each of the session lengths. Special care was taken to keep the GPS and GLONASS solutions fully consistent and comparable in particular where the station selection is concerned. We generate ERPs with a subdaily time resolution of about 1.4 hours (1/17 sidereal day). Using the session-specific normal equation systems (NEQs) containing the Earth rotation parameters with the 1.4 hours time resolution we derive in addition ERPs with a (sidereal) daily resolution. Note that this step requires the combination of the daily NEQs and a subsequent re-binning of 17 consecutive ERPs with 1/17 day time resolution into one (sidereal) daily parameter. These tests will reveal the impact of the session length on ERP

Prospect of Continuous VLBI Measurement of Earth Rotation in Monitoring Geophysical Fluids

Science.gov (United States)

Chao, Benjamin F.; Ma, Chopo; Clark, Thomas

1998-01-01

Large-scale mass transports in the geophysical fluids of the Earth system excite Earth's rotational variations in both length-of-day and polar motion. The excitation process is via the conservation of angular momentum. Therefore Earth rotation observations contain information about the integrated angular momentum (consisting of both the mass term and the motion term) of the geophysical fluids, which include atmosphere, hydrosphere, mantle, and the outer and inner cores. Such global information is often important and otherwise unattainable depending on the nature of the mass transport, its magnitude and time scale. The last few years have seen great advances in VLBI measurement of Earth rotation in precision and temporal resolution. These advances have opened new. areas in geophysical fluid studies, such as oceanic tidal angular momentum, atmospheric tides, Earth librations, and rapid atmospheric angular momentum fluctuations. Precision of 10 microseconds in UTI and 200 microarcseconds in polar motion can now be achieved on hourly basis. Building upon this heritage, the multi-network geodetic VLBI project, Continuous Observation of the Rotation of the Earth (CORE), promises to further these studies and to make possible studies on elusive but tell-tale geophysical processes such as oscillatory modes in the core and in the atmosphere. Currently the early phase of CORE is underway. Within a few years into the new mellinnium, the upcoming space gravity missions (such as GRACE) will measure the temporal variations in Earth's gravitational field, thus providing complementary information to that from Earth rotation study for a better understanding of global geophysical fluid processes.

Progress in Research on Diurnal and Semidiurnal Earth Rotation Change

Science.gov (United States)

Xu, Xueqing

2015-08-01

We mainly focus on the progress of research on high frequency changes in the earth rotation. Firstly, we review the development course and main motivating factors of the diurnal and semidiurnal earth rotation change. In recent decades, earth orientation has been monitored with increasing accuracy by advanced space-geodetic techniques, including lunar and satellite laser ranging, very long baseline interferometry and the global positioning system. We are able to obtain the Earth Rotation Parameters (ERP, polar motion and rotation rate changes) by even 1 to 2 hours observation data, form which obvious diurnal and semidiurnal signals can be detected, and compare them with the predicted results by the ocean model. Both the amplitude and phase are in good agreement in the main diurnal and semidiurnal wave frequency, especially for the UT1, whose compliance is 90%, and 60% for polar motion, there are 30% motivating factor of the diurnal and semidiurnal polar motion have not been identified. Then we comprehensively review the different types of global ocean tidal correction models since the last eighties century, as well as the application research on diurnal and semidiurnal polar motion and UT1, the current ocean tidal correction models have 10% to 20% uncertainty, and need for further refinement.

A Numerical-Analytical Approach to Modeling the Axial Rotation of the Earth

Science.gov (United States)

Markov, Yu. G.; Perepelkin, V. V.; Rykhlova, L. V.; Filippova, A. S.

2018-04-01

A model for the non-uniform axial rotation of the Earth is studied using a celestial-mechanical approach and numerical simulations. The application of an approximate model containing a small number of parameters to predict variations of the axial rotation velocity of the Earth over short time intervals is justified. This approximate model is obtained by averaging variable parameters that are subject to small variations due to non-stationarity of the perturbing factors. The model is verified and compared with predictions over a long time interval published by the International Earth Rotation and Reference Systems Service (IERS).

Oscillatory-rotational processes in the Earth motion about the center of mass: Interpolation and forecast

Science.gov (United States)

Akulenko, L. D.; Klimov, D. M.; Markov, Yu. G.; Perepelkin, V. V.

2012-11-01

The celestial-mechanics approach (the spatial version of the problem for the Earth-Moon system in the field of gravity of the Sun) is used to construct a mathematical model of the Earth's rotational-oscillatory motions. The fundamental aspects of the processes of tidal inhomogeneity in the Earth rotation and the Earth's pole oscillations are studied. It is shown that the presence of the perturbing component of gravitational-tidal forces, which is orthogonal to the Moon's orbit plane, also allows one to distinguish short-period perturbations in the Moon's motion. The obtained model of rotational-oscillatory motions of the nonrigid Earth takes into account both the basic perturbations of large amplitudes and the more complicated small-scale properties of the motion due to the Moon short-period perturbations with combination frequencies. The astrometric data of the International Earth Rotation and Reference Systems Service (IERS) are used to perform numerical simulation (interpolation and forecast) of the Earth rotation parameters (ERP) on various time intervals.

A possible interrelation between Earth rotation and climatic variability at decadal time-scale

Directory of Open Access Journals (Sweden)

Leonid Zotov

2016-05-01

Full Text Available Using multichannel singular spectrum analysis (MSSA we decomposed climatic time series into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic oscillations have been found in the global mean Earth temperature anomaly (HadCRUT4 and global mean sea level (GMSL. Similar cycles were also found in Earth rotation variation. Over the last 160 years multi-decadal change of Earth's rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth's rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes.

Empirical model of subdaily variations in the Earth rotation from GPS and its stability

Science.gov (United States)

Panafidina, N.; Kurdubov, S.; Rothacher, M.

2012-12-01

The model recommended by the IERS for these variations at diurnal and semidiurnal periods has been computed from an ocean tide model and comprises 71 terms in polar motion and Universal Time. In the present study we compute an empirical model of variations in the Earth rotation on tidal frequencies from homogeneously re-processed GPS-observations over 1994-2007 available as free daily normal equations. We discuss the reliability of the obtained amplitudes of the ERP variations and compare results from GPS and VLBI data to identify technique-specific problems and instabilities of the empirical tidal models.

Complex demodulation in VLBI estimation of high frequency Earth rotation components

Science.gov (United States)

Böhm, S.; Brzeziński, A.; Schuh, H.

2012-12-01

The spectrum of high frequency Earth rotation variations contains strong harmonic signal components mainly excited by ocean tides along with much weaker non-harmonic fluctuations driven by irregular processes like the diurnal thermal tides in the atmosphere and oceans. In order to properly investigate non-harmonic phenomena a representation in time domain is inevitable. We present a method, operating in time domain, which is easily applicable within Earth rotation estimation from Very Long Baseline Interferometry (VLBI). It enables the determination of diurnal and subdiurnal variations, and is still effective with merely diurnal parameter sampling. The features of complex demodulation are used in an extended parameterization of polar motion and universal time which was implemented into a dedicated version of the Vienna VLBI Software VieVS. The functionality of the approach was evaluated by comparing amplitudes and phases of harmonic variations at tidal periods (diurnal/semidiurnal), derived from demodulated Earth rotation parameters (ERP), estimated from hourly resolved VLBI ERP time series and taken from a recently published VLBI ERP model to the terms of the conventional model for ocean tidal effects in Earth rotation recommended by the International Earth Rotation and Reference System Service (IERS). The three sets of tidal terms derived from VLBI observations extensively agree among each other within the three-sigma level of the demodulation approach, which is below 6 μas for polar motion and universal time. They also coincide in terms of differences to the IERS model, where significant deviations primarily for several major tidal terms are apparent. An additional spectral analysis of the as well estimated demodulated ERP series of the ter- and quarterdiurnal frequency bands did not reveal any significant signal structure. The complex demodulation applied in VLBI parameter estimation could be demonstrated a suitable procedure for the reliable reproduction of

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

Science.gov (United States)

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).

Combining Radar and Daily Precipitation Data to Estimate Meaningful Sub-daily Precipitation Extremes

Science.gov (United States)

Pegram, G. G. S.; Bardossy, A.

2016-12-01

Short duration extreme rainfalls are important for design. The purpose of this presentation is not to improve the day by day estimation of precipitation, but to obtain reasonable statistics for the subdaily extremes at gauge locations. We are interested specifically in daily and sub-daily extreme values of precipitation at gauge locations. We do not employ the common procedure of using time series of control station to determine the missing data values in a target. We are interested in individual rare events, not sequences. The idea is to use radar to disaggregate daily totals to sub-daily amounts. In South Arica, an S-band radar operated relatively continuously at Bethlehem from 1998 to 2003, whose scan at 1.5 km above ground [CAPPI] overlapped a dense (10 km spacing) set of 45 pluviometers recording in the same 6-year period. Using this valuable set of data, we are only interested in rare extremes, therefore small to medium values of rainfall depth were neglected, leaving 12 days of ranked daily maxima in each set per year, whose sum typically comprised about 50% of each annual rainfall total. The method presented here uses radar for disaggregating daily gauge totals in subdaily intervals down to 15 minutes in order to extract the maxima of sub-hourly through to daily rainfall at each of 37 selected radar pixels [1 km square in plan] which contained one of the 45 pluviometers not masked out by the radar foot-print. The pluviometer data were aggregated to daily totals, to act as if they were daily read gauges; their only other task was to help in the cross-validation exercise. The extrema were obtained as quantiles by ordering the 12 daily maxima of each interval per year. The unusual and novel goal was not to obtain the reproduction of the precipitation matching in space and time, but to obtain frequency distributions of the gauge and radar extremes, by matching their ranks, which we found to be stable and meaningful in cross-validation tests. We provide and

Interaction between subdaily Earth rotation parameters and GPS orbits

Science.gov (United States)

Panafidina, Natalia; Seitz, Manuela; Hugentobler, Urs

2013-04-01

In processing GPS observations the geodetic parameters like station coordinates and ERPs (Earth rotation parameters) are estimated w.r.t. the celestial reference system realized by the satellite orbits. The interactions/correlations between estimated GPS orbis and other parameters may lead to numerical problems with the solution and introduce systematic errors in the computed values: the well known correlations comprise 1) the correlation between the orbital parameters determining the orientation of the orbital plane in inertial space and the nutation and 2) in the case of estimating ERPs with subdaily resolution the correlation between retrograde diurnal polar motion and nutation (and so the respective orbital elements). In this contribution we study the interaction between the GPS orbits and subdaily model for the ERPs. Existing subdaily ERP model recommended by the IERS comprises ~100 terms in polar motion and ~70 terms in Universal Time at diurnal and semidiurnal tidal periods. We use a long time series of daily normal equation systems (NEQ) obtaine from GPS observations from 1994 till 2007 where the ERPs with 1-hour resolution are transformed into tidal terms and the influence of the tidal terms with different frequencies on the estimated orbital parameters is considered. We found that although there is no algebraic correlation in the NEQ between the individual orbital parameters and the tidal terms, the changes in the amplitudes of tidal terms with periods close to 24 hours can be better accmodated by systematic changes in the orbital parameters than for tidal terms with other periods. Since the variation in Earth rotation with the period of siderial day (23.93h, tide K1) in terrestrial frame has in inertial space the same period as the period of revolution of GPS satellites, the K1 tidal term in polar motion is seen by the satellites as a permanent shift. The tidal terms with close periods (from ~24.13h to ~23.80h) are seen as a slow rotation of the

Monitoring of Earth Rotation by VLBI

Science.gov (United States)

Ma., Chopo; Macmillan, D. S.

2000-01-01

Monitoring Earth rotation with Very Long Baseline Interferometry (VLBI) has unique potential because of direct access to the Celestial Reference System (CRF and Terrestrial Reference System (TRF) and the feasibility of re-analyzing the entire data set. While formal precision of better than 0.045 mas for pole and 0.002 ms for UT 1 has been seen in the best 24-hr data, the accuracy of the Earth Orientation Parameter (EOP) time series as a whole is subject to logistical, operational, analytical and conceptual constraints. The current issues related to the VLBI data set and the CORE program for greater time resolution such as analysis consistency, network jitter and reference frame stability will be discussed.

Rotational excitation of HCN by para- and ortho-H{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Vera, Mario Hernández, E-mail: marhvera@gmail.com [LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 1123, 76 063 Le Havre cedex (France); InSTEC, Quinta de Los Molinos, Plaza, La Habana 10600 (Cuba); Kalugina, Yulia [LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 1123, 76 063 Le Havre cedex (France); Tomsk State University, 36 Lenin av., Tomsk 634050 (Russian Federation); Denis-Alpizar, Otoniel [Université de Bordeaux, ISM, CNRS UMR 5255, 33405 Talence Cedex (France); Departamento de Física, Universidad de Matanzas, Matanzas 40100 (Cuba); Stoecklin, Thierry [Université de Bordeaux, ISM, CNRS UMR 5255, 33405 Talence Cedex (France); Lique, François, E-mail: francois.lique@univ-lehavre.fr [LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 1123, 76 063 Le Havre cedex (France)

2014-06-14

Rotational excitation of the hydrogen cyanide (HCN) molecule by collisions with para-H{sub 2}( j = 0, 2) and ortho-H{sub 2}( j = 1) is investigated at low temperatures using a quantum time independent approach. Both molecules are treated as rigid rotors. The scattering calculations are based on a highly correlated ab initio 4-dimensional (4D) potential energy surface recently published. Rotationally inelastic cross sections among the 13 first rotational levels of HCN were obtained using a pure quantum close coupling approach for total energies up to 1200 cm{sup −1}. The corresponding thermal rate coefficients were computed for temperatures ranging from 5 to 100 K. The HCN rate coefficients are strongly dependent on the rotational level of the H{sub 2} molecule. In particular, the rate coefficients for collisions with para-H{sub 2}( j = 0) are significantly lower than those for collisions with ortho-H{sub 2}( j = 1) and para-H{sub 2}( j = 2). Propensity rules in favor of even Δj transitions were found for HCN in collisions with para-H{sub 2}( j = 0) whereas propensity rules in favor of odd Δj transitions were found for HCN in collisions with H{sub 2}( j ⩾ 1). The new rate coefficients were compared with previously published HCN-para-H{sub 2}( j = 0) rate coefficients. Significant differences were found due the inclusion of the H{sub 2} rotational structure in the scattering calculations. These new rate coefficients will be crucial to improve the estimation of the HCN abundance in the interstellar medium.

Russian State Time and Earth Rotation Service: Observations, Eop Series, Prediction

Science.gov (United States)

Kaufman, M.; Pasynok, S.

2010-01-01

Russian State Time, Frequency and Earth Rotation Service provides the official EOP data and time for use in scientific, technical and metrological works in Russia. The observations of GLONASS and GPS on 30 stations in Russia, and also the Russian and worldwide observations data of VLBI (35 stations) and SLR (20 stations) are used now. To these three series of EOP the data calculated in two other Russian analysis centers are added: IAA (VLBI, GPS and SLR series) and MCC (SLR). Joint processing of these 7 series is carried out every day (the operational EOP data for the last day and the predicted values for 50 days). The EOP values are weekly refined and systematic errors of every individual series are corrected. The combined results become accessible on the VNIIFTRI server (ftp.imvp.ru) approximately at 6h UT daily.

Rare-earth doping of high T/sub c/ superconducting perovskites

International Nuclear Information System (INIS)

Mc Kinnon, W.R.; Tarascon, J.M.; Greene, L.H.; Hull, G.W.

1987-01-01

In most superconductors, the magnetic moments of rare-earth (Re) ions interact with the conduction electrons and break the Cooper pairs, supressing or destroying superconductivity. But in the perovskite-based superconductors discovered recently, the rare-earth ions are separated from the copper and oxygen where the superconducting electrons are believed to be located. The authors study the effects of rare-earth doping in both the 40K La/sub 2-x/Sr/sub x/CuO/sub 4-y/ system and 90K YBa/sub 2/Cu/sub 3/O/sub 7-x/ system. In these materials, the RE ions only weakly affect superconductivity, and the effects we do see are more strongly correlated with changes in the volume of the crystal than with the magnetism of the rare earths

Modelling of Sub-daily Hydrological Processes Using Daily Time-Step Models: A Distribution Function Approach to Temporal Scaling

Science.gov (United States)

Kandel, D. D.; Western, A. W.; Grayson, R. B.

2004-12-01

Mismatches in scale between the fundamental processes, the model and supporting data are a major limitation in hydrologic modelling. Surface runoff generation via infiltration excess and the process of soil erosion are fundamentally short time-scale phenomena and their average behaviour is mostly determined by the short time-scale peak intensities of rainfall. Ideally, these processes should be simulated using time-steps of the order of minutes to appropriately resolve the effect of rainfall intensity variations. However, sub-daily data support is often inadequate and the processes are usually simulated by calibrating daily (or even coarser) time-step models. Generally process descriptions are not modified but rather effective parameter values are used to account for the effect of temporal lumping, assuming that the effect of the scale mismatch can be counterbalanced by tuning the parameter values at the model time-step of interest. Often this results in parameter values that are difficult to interpret physically. A similar approach is often taken spatially. This is problematic as these processes generally operate or interact non-linearly. This indicates a need for better techniques to simulate sub-daily processes using daily time-step models while still using widely available daily information. A new method applicable to many rainfall-runoff-erosion models is presented. The method is based on temporal scaling using statistical distributions of rainfall intensity to represent sub-daily intensity variations in a daily time-step model. This allows the effect of short time-scale nonlinear processes to be captured while modelling at a daily time-step, which is often attractive due to the wide availability of daily forcing data. The approach relies on characterising the rainfall intensity variation within a day using a cumulative distribution function (cdf). This cdf is then modified by various linear and nonlinear processes typically represented in hydrological and

Solar excitation of bicentennial Earth rotation oscillations

Czech Academy of Sciences Publication Activity Database

Ron, Cyril; Chapanov, Y.; Vondrák, Jan

2012-01-01

Roč. 9, č. 3 (2012), s. 259-268 ISSN 1214-9705 R&D Projects: GA ČR GA205/08/0908 Grant - others:Bulgarian NSF(BG) DO02-275; FP7(BG) MCA PIRSES-GA-2009-246874 Institutional support: RVO:67985815 Keywords : Earth rotation * solar activity Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.530, year: 2011

Synthesis and characterization of the novel rare earth orthophosphates Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Schildhammer, Daniel; Petschnig, Lucas L.; Fuhrmann, Gerda; Heymann, Gunter; Schottenberger, Herwig; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Tribus, Martina [Innsbruck Univ. (Austria). Inst. fuer Mineralogie und Petrographie

2016-02-01

The new mixed rare earth (RE) orthophosphates Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} were synthesized by a classical solid state reaction in an electrical furnace at 1200 C. As starting materials, the corresponding rare earth oxides and diammonium hydrogen phosphate were used. The powder diffraction analyses revealed that the new compounds Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} crystallize in a zircon-type structure being isostructural with the rare earth orthophosphate YPO{sub 4}. Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} crystallize in the tetragonal space group I4{sub 1}/amd (no. 141) with four formula units in the unit cell. The structural parameters based on Rietveld refinements are a = 687.27(2), c = 601.50(2) pm, V = 0.28412(1) nm{sup 3}, R{sub p} = 0.0143, and R{sub wp} = 0.0186 (all data) for Y{sub 0.5}Er{sub 0.5}PO{sub 4} and a = 684.61(2), c = 599.31(2) pm, V = 0.28089(2) nm{sup 3}, R{sub p} = 0.0242, and R{sub wp} = 0.0313 (all data) for Y{sub 0.5}Yb{sub 0.5}PO{sub 4}. Furthermore, the structure of Y{sub 0.5}Er{sub 0.5}PO{sub 4} was refined from single-crystal X-ray diffraction data: a = 687.78(5), c = 601.85(4) pm, V = 0.28470(5) nm{sup 3}, R{sub 1} = 0.0165, and wR{sub 2} = 0.0385 (all data). In both compounds, the rare earth metal ions are eightfold coordinated by oxygen atoms, forming two unique interlocking tetrahedra with two individual RE-O distances. The tetrahedral phosphate groups [PO{sub 4}]{sup 3-} are slightly distorted in both compounds. The individual rare earth ions share a common position (Wyckoff site 4a). The presence of two rare earth ions in the structures of the new orthophosphates Y{sub 0.5}Er{sub 0.5}PO{sub 4} and Y{sub 0.5}Yb{sub 0.5}PO{sub 4} was additionally confirmed by single-crystal EDX spectroscopy revealing a ratio of 1:1.

The influence of geophysical processes on the Earth's rotation

International Nuclear Information System (INIS)

Nastula, J.

1985-01-01

The problem of the influence of geophysical processes on the Earth's rotation is presented. The role of these processes in the variations of the length of day is described in this part. 27 refs., 19 figs. (author)

On Physical Interpretation of the In-Site Measurement of Earth Rotation by Ring Laser Gyrometers

Science.gov (United States)

Chao, B. F.

2004-01-01

Large ring laser gyrometers under development have demonstrated the capability of detecting minute ground motions and deformations on a wide range of timescales. The next challenge and goal is to measure the Earth's rotation variations to a precision that rivals that of the present space-geodesy techniques, thus providing an in-situ (and cost effective alternatives of Earth rotation measurement for geophysical research and geodetic applications. Aside from thermal and mechanical instabilities, "undesirable" ground motion and tilt that appear in the signal will need to be removed before any variation in Earth rotation can be detected. Removal of these signals, some of them are larger than the sought rotation signals, has been a typical procedure in many precise geophysical instruments, such as gravimeters, seismometers, and tiltmeters. The remaining Earth rotation signal resides in both the spin around the axis and in the orientation of the axis. In the case of the latter, the in-situ measurement is complementary to the space-geodetic observables in terms of polar motion and nutation, a fact to be exploited.

ROTATIONAL VARIABILITY OF EARTH'S POLAR REGIONS: IMPLICATIONS FOR DETECTING SNOWBALL PLANETS

International Nuclear Information System (INIS)

Cowan, Nicolas B.; Robinson, Tyler; Agol, Eric; Meadows, Victoria S.; Shields, Aomawa L.; Livengood, Timothy A.; Deming, Drake; A'Hearn, Michael F.; Wellnitz, Dennis D.; Charbonneau, David; Lisse, Carey M.; Seager, Sara

2011-01-01

We have obtained the first time-resolved, disk-integrated observations of Earth's poles with the Deep Impact spacecraft as part of the EPOXI mission of opportunity. These data mimic what we will see when we point next-generation space telescopes at nearby exoplanets. We use principal component analysis (PCA) and rotational light curve inversion to characterize color inhomogeneities and map their spatial distribution from these unusual vantage points, as a complement to the equatorial views presented by Cowan et al. in 2009. We also perform the same PCA on a suite of simulated rotational multi-band light curves from NASA's Virtual Planetary Laboratory three-dimensional spectral Earth model. This numerical experiment allows us to understand what sorts of surface features PCA can robustly identify. We find that the EPOXI polar observations have similar broadband colors as the equatorial Earth, but with 20%-30% greater apparent albedo. This is because the polar observations are most sensitive to mid-latitudes, which tend to be more cloudy than the equatorial latitudes emphasized by the original EPOXI Earth observations. The cloudiness of the mid-latitudes also manifests itself in the form of increased variability at short wavelengths in the polar observations and as a dominant gray eigencolor in the south polar observation. We construct a simple reflectance model for a snowball Earth. By construction, our model has a higher Bond albedo than the modern Earth; its surface albedo is so high that Rayleigh scattering does not noticeably affect its spectrum. The rotational color variations occur at short wavelengths due to the large contrast between glacier ice and bare land in those wavebands. Thus, we find that both the broadband colors and diurnal color variations of such a planet would be easily distinguishable from the modern-day Earth, regardless of viewing angle.

The methyl rotational potentials of Ga(CH sub 3) sub 3 derived by neutron spectroscopy

CERN Document Server

Prager, M; Parker, S F; Desmedt, A; Lechner, R E

2002-01-01

High resolution neutron spectra of Ga(CH sub 3) sub 3 show tunnelling transitions between 4.5 and 19 mu eV. The spectrum can be explained within the single-particle model on the basis of the monoclinic C2/c (Z = 16) low temperature crystal structure of Ga(CH sub 3) sub 3 with six inequivalent methyl groups in the unit cell. The overlapping tunnelling lines prevent the extraction of temperature dependent linewidths which would allow us to assign the librational energies measured in the phonon density of states. Classical rotational motion is studied by quasielastic neutron scattering. Three activation energies could be extracted. Methyl librations, tunnelling energies and barrier heights are combined with consistent intensities into rotational potentials. Only the concerted application of all spectroscopic techniques yields a conclusive description.

Antihysteresis of perceived longitudinal body axis during continuous quasi-static whole-body rotation in the earth-vertical roll plane.

Science.gov (United States)

Tatalias, M; Bockisch, C J; Bertolini, G; Straumann, D; Palla, A

2011-03-01

Estimation of subjective whole-body tilt in stationary roll positions after rapid rotations shows hysteresis. We asked whether this phenomenon is also present during continuous quasi-static whole-body rotation and whether gravitational cues are a major contributing factor. Using a motorized turntable, 8 healthy subjects were rotated continuously about the earth-horizontal naso-occipital axis (earth-vertical roll plane) and the earth-vertical naso-occipital axis (earth-horizontal roll plane). In both planes, three full constant velocity rotations (2°/s) were completed in clockwise and counterclockwise directions (acceleration = 0.05°/s(2), velocity plateau reached after 40 s). Subjects adjusted a visual line along the perceived longitudinal body axis (pLBA) every 2 s. pLBA deviation from the longitudinal body axis was plotted as a function of whole-body roll position, and a sine function was fitted. At identical whole-body earth-vertical roll plane positions, pLBA differed depending on whether the position was reached by a rotation from upright or by passing through upside down. After the first 360° rotation, pLBA at upright whole-body position deviated significantly in the direction of rotation relative to pLBA prior to rotation initiation. This deviation remained unchanged after subsequent full rotations. In contrast, earth-horizontal roll plane rotations resulted in similar pLBA before and after each rotation cycle. We conclude that the deviation of pLBA in the direction of rotation during quasi-static earth-vertical roll plane rotations reflects static antihysteresis and might be a consequence of the known static hysteresis of ocular counterroll: a visual line that is perceived that earth-vertical is expected to be antihysteretic, if ocular torsion is hysteretic.

Earth rotation, station coordinates and orbit determination from satellite laser ranging

Science.gov (United States)

Murata, Masaaki

The Project MERIT, a special program of international colaboration to Monitor Earth Rotation and Intercompare the Techniques of observation and analysis, has come to an end with great success. Its major objective was to evaluate the ultimate potential of space techniques such as VLBI and satellite laser ranging, in contrast with the other conventional techniques, in the determination of rotational dynamics of the earth. The National Aerospace Laboratory (NAL) has officially participated in the project as an associate analysis center for satellite laser technique for the period of the MERIT Main Campaign (September 1983-October 1984). In this paper, the NAL analysis center results are presented.

Foucault and the rotation of the Earth

Science.gov (United States)

Sommeria, Joël

2017-11-01

In February 1851, Léon Foucault published in the Comptes rendus his famous pendulum experiment performed at the "Observatoire de Paris". This ended two centuries of quest for an experimental demonstration of Earth rotation. One month later, the experiment was reproduced at larger scale in the Panthéon and, as early as the summer of 1851, it was being repeated in many places across the world. The next year, Foucault invented the gyroscope to get a still more direct proof of Earth rotation. The theory relied on the masterpiece treatise of Laplace on celestial mechanics, published in 1805, which already contained the mathematical expression of the force that would be discovered by Gustave Coriolis 30 years later. The idea of a fictitious inertial force proposed by Coriolis prevailed by the end of 19th century, as it was conceptually simpler than Laplace's approach. The full theory of the Foucault pendulum, taking into account its unavoidable imperfections, was not obtained until three decades later by Kamerlingh Onnes, the future discoverer of liquid helium and superconductivity. Today, Foucault's exceptional creativity is still a source of inspiration for research and the promotion of science through experimental proofs widely available to the public.

Influence of rare-earth ions on SiO{sub 2}-Na{sub 2}O-RE{sub 2}O{sub 3} glass structure

Energy Technology Data Exchange (ETDEWEB)

Johnson, J A [Department of Materials Science and Engineering, University of Tennessee Space Institute, Tullahoma, TN 37388 (United States); Benmore, C J [X-ray Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Holland, D [Department of Physics, University of Warwick, CV4 7AL (United Kingdom); Du, J [Department of Material Science and Engineering, University of North Texas, Denton, TX 76203 (United States); Beuneu, B [Laboratoire Leon Brillouin, CEA-CNRS, CEA/Saclay, F-91191 Gif-sur-Yvette (France); Mekki, A, E-mail: jjohnson@utsi.edu [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2011-02-16

Praseodymium and europium sodium silicate glasses of nominal composition (SiO{sub 2}){sub 0.70-x}(Na{sub 2}O){sub 0.30}(RE{sub 2}O{sub 3}){sub x}, where RE is the rare earth and 0 {<=} x {<=} 0.10, were studied by neutron and high-energy x-ray scattering and classical molecular dynamics simulations. The observation of a significant x-ray intensity in doped as compared to un-doped glasses is indicative of RE-RE correlations at a distance of {approx} 3.7-3.9 A, much shorter than would be expected for a homogeneous distribution, suggesting that clustering of the rare-earth cations occurs in both these glass systems at low concentrations. Above x = 0.075 (nominal), minimal changes in this region indicate that the RE atoms are incorporated much more randomly into the glass structure. The molecular dynamics simulations suggest that the rare-earth ions enter the sodium-rich regions in the sodium silicate glasses and act as modifiers. A cluster analysis performed on the model systems indicates that the tendency for clustering is higher in praseodymium-containing glasses than in the europium glasses.

Communication: Rovibrationally selected absolute total cross sections for the reaction H{sub 2}O{sup +}(X{sup 2}B{sub 1}; v{sub 1}{sup +}v{sub 2}{sup +}v{sub 3}{sup +}= 000; N{sup +}{sub Ka+Kc+)}+ D{sub 2}: Observation of the rotational enhancement effect

Energy Technology Data Exchange (ETDEWEB)

Xu Yuntao; Xiong Bo; Chang, Yih Chung; Ng, C. Y. [Department of Chemistry, University of California, Davis, California 95616 (United States)

2012-12-28

By employing the newly established vacuum ultraviolet laser pulsed field ionization-photoion (PFI-PI) double quadrupole-double octopole ion guide apparatus, we have measured the rovibrationally selected absolute total cross sections of the ion-molecule reaction H{sub 2}O{sup +}(X{sup 2}B{sub 1}; v{sub 1}{sup +}v{sub 2}{sup +}v{sub 3}{sup +}= 000; N{sup +}{sub Ka+Kc+)}+ D{sub 2}{yields} H{sub 2}DO{sup +}+ D in the center-of-mass collision energy (E{sub cm}) range of 0.05-10.00 eV. The pulsing scheme used for the generation of PFI-PIs has made possible the preparation of reactant H{sub 2}O{sup +}(X{sup 2}B{sub 1}; v{sub 1}{sup +}v{sub 2}{sup +}v{sub 3}{sup +}= 000) ions in single N{sup +}{sub Ka+Kc+} rotational levels with high kinetic energy resolutions. The absolute total cross sections observed in different N{sup +}{sub Ka+Kc+} levels with rotational energies in the range of 0-200 cm{sup -1} were found to exhibit a significant rotational enhancement on the reactivity for the titled reaction. In contrast, the measured cross sections reveal a decreasing trend with increasing E{sub cm}, indicating that the rotational enhancement observed is not a total energy effect, but a dynamical effect. Furthermore, the rotational enhancement is found to be more pronounced as E{sub cm} is decreased. This experiment provided evidence that the coupling of the core rotational angular momentum with the orbital angular momentum could play a role in chemical reactivity, particularly at low E{sub cm}.

Dynamic Effects of the Earth's Rotation Caused by the Annual and Semi-Annual Cyclic Mass Redistribution of the Planet

Directory of Open Access Journals (Sweden)

M. Yu. Barkin

2016-01-01

Full Text Available The paper deals with development of the theory of perturbed rotational motion of a celestial body with variable geometry of the masses. Its main task is to study the impact of annual and semi-annual variations of the Earth's mass geometry (a component of its inertia tensor, as well as a component of its relative angular momentum, on the movement of the Earth's poles and its axial rotation. The body is considered to be a free (isolated, and the problem formulation corresponds to the classical Liouville problem on rotation of a variable body. Euler conical movement of the axially symmetric body with an arbitrary constant half-angle  is assumed as the unperturbed motion. In the classical theory of the Earth's rotation this angle is usually assumed to be zero.In the last 20 years, accuracy to determine the Earth rotation parameters owing to using methods of space geodesy and method of Very Long Baseline Interferometry (VLBI has increased by about three orders of magnitude and has made about  i.e., in angle measure it is about 10 - 20 arc-microseconds. According to experts, the theory of the Earth's rotation with such precision is not created yet. The paper is focused just on the new dynamic studies of the Earth rotation at a higher level of accuracy than has been done in previous studies, using a new approach to the problem, based on the new forms of the equations of motion (in the Andoyer variables and the analytical methods of perturbation theory (small parameter method.The problem of perturbed rotational motion with variable geometry and variable mass relative angular momentum in the first approximation is solved in Andoyer variables and projections of the angular velocity of the planet rotation. The analytical solution allows us to run applications to study dynamic effects from above factors for various bodies in the solar system, including the Earth. The solution allowed us to obtain the following parameters of the fundamental effects in the

Solar activity, tidal friction and the earth rotation over the last 2000 years

International Nuclear Information System (INIS)

Kiselev, V.M.

1981-01-01

The tidal retardations of the Earth rotation and orbital motion of the Moon on Dynamical Time are discussed. The secular deceleration of the lunar motion deduced from an analysis of the anciept and medieval eclipses is lapger thap that obtained from recent (telescopic) observations. This discrepancy is shown to vanish if the Earth acceleration due to secular change of solar activity is taken into consideration. Therefore, one may suggest that the mean tidal friction has remained essentially constant over the last two millennia. Nontidal variations of the Earth rotation velocity in the historical past as well as at present time are shown to be caused by solar activity changes [ru

Excitation of Earth Rotation Variations "Observed" by Time-Variable Gravity

Science.gov (United States)

Chao, Ben F.; Cox, C. M.

2005-01-01

Time variable gravity measurements have been made over the past two decades using the space geodetic technique of satellite laser ranging, and more recently by the GRACE satellite mission with improved spatial resolutions. The degree-2 harmonic components of the time-variable gravity contain important information about the Earth s length-of-day and polar motion excitation functions, in a way independent to the traditional "direct" Earth rotation measurements made by, for example, the very-long-baseline interferometry and GPS. In particular, the (degree=2, order= 1) components give the mass term of the polar motion excitation; the (2,O) component, under certain mass conservation conditions, gives the mass term of the length-of-day excitation. Combining these with yet another independent source of angular momentum estimation calculated from global geophysical fluid models (for example the atmospheric angular momentum, in both mass and motion terms), in principle can lead to new insights into the dynamics, particularly the role or the lack thereof of the cores, in the excitation processes of the Earth rotation variations.

Observing atmospheric tides in Earth rotation parameters with VLBI

Science.gov (United States)

Girdiuk, Anastasiia; Böhm, Johannes; Schindelegger, Michael

2015-04-01

In this study, we assess the contribution of diurnal (S1) and semi-diurnal (S2) atmospheric tides to variations in Earth rotation by analyzing Very Long Baseline Interferometry (VLBI) observations. Particular emphasis is placed on the dependency of S1 and S2 estimates on varying settings in the a priori delay model. We use hourly Earth rotation parameters (ERP) of polar motion and UT1 as determined with the Vienna VLBI Software (VieVS) from 25 years of VLBI observations and we adjust diurnal and semi-diurnal amplitudes to the hourly ERP estimates after disregarding the effect of high-frequency ocean tides. Prograde and retrograde polar motion coefficients are obtained for several solutions differing in processing strategies (with/without thermal deformation, time span of observations, choice of a priori ERP model and celestial pole offsets) and we compare the corresponding harmonics with those derived from atmospheric and non-tidal oceanic angular momentum estimates.

The Irregularity of the Earth's Rotation as a Planetary Geomorphological and Geotectonic Factor

National Research Council Canada - National Science Library

Stovas, M. V

1963-01-01

Though the idea has not been much discussed for the last fifty years, variation in the rotation of the earth must be accompanied by change of the earth's equatorial and polar radii, change of meridian...

Main effects of the Earth's rotation on the stationary states of ultra-cold neutrons

International Nuclear Information System (INIS)

Arminjon, Mayeul

2008-01-01

The relativistic corrections in the Hamiltonian for a particle in a uniformly rotating frame are discussed. They are shown to be negligible in the case of ultra-cold neutrons (UCN) in the Earth's gravity. The effect, on the energy levels of UCN, of the main term due to the Earth's rotation, i.e. the angular-momentum term, is calculated. The energy shift is found proportional to the energy level itself

Correlations between the geomagnetic field variations, the fluctuations of the earth`s rotation and climate change

Energy Technology Data Exchange (ETDEWEB)

Greiner-Mai, H; Jochmann, H

1995-03-01

The amplitude spectra of global geophysical phenomena were investigated to motivate research of physical connections between them. The suggested causality was derived from comparison of the spectra, and from cross correlation functions. The following global parameters were discussed: For the earth rotation by the variations of the length of day, for the geomagnetic variation by the global field intensity, changes of the dipole axis and the westward drift, and for climate change by the atmospheric excitation function derived from air pressure variations, and temperature variations. The model of atmospheric excitation, which can be proved most exactly for the annual variations of length of day, is responsible for the 11 and 22 years periods, too. It failed for longer periods, e.g. partially for the 30 years periods and completely for the 60 to 80 years periods, which were also discovered in the mean temperature and geomagnetic field variations. Therefore, it was suggested that longer periods in climate change and in the variations of the earth`s rotation are caused independently by the same process in the earth core, provided that a physical influence of the geomagnetic field on climate will be accepted in future. The investigation was completed by comparison with the spectra of some local temperature variations in Europe. (orig.)

Accounting of fundamental components of the rotation parameters of the Earth in the formation of a high-accuracy orbit of navigation satellites

Science.gov (United States)

Markov, Yu. G.; Mikhailov, M. V.; Pochukaev, V. N.

2012-07-01

An analysis of perturbing factors influencing the motion of a navigation satellite (NS) is carried out, and the degree of influence of each factor on the GLONASS orbit is estimated. It is found that fundamental components of the Earth's rotation parameters (ERP) are one substantial factor commensurable with maximum perturbations. Algorithms for the calculation of orbital perturbations caused by these parameters are given; these algorithms can be implemented in a consumer's equipment. The daily prediction of NS coordinates is performed on the basis of real GLONASS satellite ephemerides transmitted to a consumer, using the developed prediction algorithms taking the ERP into account. The obtained accuracy of the daily prediction of GLONASS ephemerides exceeds by tens of times the accuracy of the daily prediction performed using algorithms recommended in interface control documents.

Mode cross coupling observations with a rotation sensor

Science.gov (United States)

Nader-Nieto, M. F.; Igel, H.; Ferreira, A. M.; Al-Attar, D.

2013-12-01

The Earth's free oscillations induced by large earthquakes have been one of the most important ways to measure the Earth's internal structure and processes. They provide important large scale constraints on a variety of elastic parameters, attenuation and density of the Earth's deep interior. The potential of rotational seismic records for long period seismology was proven useful as a complement to traditional measurements in the study of the Earth's free oscillations. Thanks to the high resolution of the G-ring laser located at Geodetic Observatory Wettzell, Germany, we are now able to study the spectral energy generated by rotations in the low frequency range. On a SNREI Earth, a vertical component rotational sensor is primarily excited by horizontally polarised shear motions (SH waves, Love waves) with theoretically no sensitivity to compressional waves and conversions (P-SV) and Rayleigh waves. Consequently, in the context of the Earth's normal modes, this instrument detects mostly toroidal modes. Here, we present observations of spectral energy of both toroidal and spheroidal normal modes in the G-ring Laser records of one of the largest magnitude events recently recorded: Tohoku-Oki, Japan, 2011. In an attempt to determine the mechanisms responsible for spheroidal energy in the vertical axes rotational spectra, we first rule out instrumental effects as well as the effect of local heterogeneity. Second, we carry out a simulation of an ideal rotational sensor taking into account the effects of the Earth's daily rotation, its hydrostatic ellipticity and structural heterogeneity, finding a good fit to the data. Simulations considering each effect separately are performed in order to evaluate the sensitivity of rotational motions to global effects with respect to traditional translation measurements.

RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd). Syntheses of three new rare earth borates isotypic to Ce{sub 2}B{sub 8}O{sub 15}

Energy Technology Data Exchange (ETDEWEB)

Glaetzle, Matthias; Hoerder, Gregor J.; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

2016-08-01

The rare earth borates RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd) were synthesized in a Walker-type multianvil apparatus under conditions of 5.5 GPa and 1100 C. Starting from the corresponding rare earth oxides and boron oxide, the syntheses yielded crystalline products of all new compounds that allowed crystal structure analyses based on single-crystal X-ray diffraction data for La{sub 2}B{sub 8}O{sub 15} and Nd{sub 2}B{sub 8}O{sub 15}. The compound Pr{sub 2}B{sub 8}O{sub 15} could be characterized via X-ray powder diffractometry. The results show that the new compounds crystallize isotypically to Ce{sub 2}B{sub 8}O{sub 15} in the monoclinic space group P2/c. The infrared spectra of RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd) have also been studied.

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

Science.gov (United States)

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.

Towards Sub-Microarsecond Rigid Earth Nutation Series in the Hamiltonian Theory

National Research Council Canada - National Science Library

Souchay, Jean; Folgueira, M

2000-01-01

...) are based on the works of Kinoshita (1977) and Wahr (1979). In Kinoshita's work, the rigid Earth nutation series were calculated by the application of the Hamiltonian canonical equations to the rotation of the rigid and elliptical Earth...

Nystagmus responses in a group of normal humans during earth-horizontal axis rotation

Science.gov (United States)

Wall, Conrad, III; Furman, Joseph M. R.

1989-01-01

Horizontal eye movement responses to earth-horizontal yaw axis rotation were evaluated in 50 normal human subjects who were uniformly distributed in age (20-69 years) and each age group was then divided by gender. Subjects were rotated with eyes open in the dark, using clockwise and counter-clockwise 60 deg velocity trapezoids. The nystagmus slow component velocity is analyzed. It is shown that, despite large intersubject variability, parameters which describe earth-horizontal yaw axis responses are loosely interrelated, and some of them vary significantly with gender and age.

Magnetic interactions in rhenium-containing rare earth double perovskites Sr{sub 2}LnReO{sub 6} (Ln=rare earths)

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, Atsuhide; Doi, Yoshihiro; Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp

2017-04-15

The perovskite-type compounds containing both rare earth and rhenium Sr{sub 2}LnReO{sub 6} (Ln=Y, Tb-Lu) have been prepared. Powder X-ray diffraction measurements and Rietveld analysis show that Ln{sup 3+} and Re{sup 5+} ions are structurally ordered at the B site of the perovskite SrBO{sub 3}. Magnetic anomalies are found in their magnetic susceptibility and specific heat measurements at 2.6–20 K for Ln=Y, Tb, Dy, Yb, Lu compounds. They are due to magnetic interactions between Re{sup 5+} ions. The results of the magnetic hysteresis and remnant magnetization measurements for Sr{sub 2}YReO{sub 6} and Sr{sub 2}LuReO{sub 6} indicate that the antiferromagnetic interactions between Re{sup 5+} ions below transition temperatures have a weak ferromagnetic component. The analysis of the magnetic specific heat data for Sr{sub 2}YbReO{sub 6} shows that both the Yb{sup 3+} and Re{sup 5+} ions magnetically order at 20 K. For the case of Sr{sub 2}DyReO{sub 6}, magnetic ordering of the Re{sup 5+} moments occurs at 93 K, and with decreasing temperature, the moments of Dy{sup 3+} ferromagnetically order at 5 K from the measurements of magnetic susceptibility and specific heat. - Graphical abstract: Crystal structure of double perovskite Sr{sub 2}LnReO{sub 6}. Red and black lines show cubic and monoclinic unit cells, respectively. - Highlights: • Double perovskites Sr{sub 2}LnReO{sub 6} (Ln=rare earths) were prepared. • They show an antiferromagnetic transition at 2.6–20 K. • In Sr{sub 2}DyReO{sub 6}, Dy and Re moments magnetically order at 5 and 93 K, respectively.

A fluid Foucault pendulum: the impossibility of achieving solid-body rotation on Earth

Science.gov (United States)

Blum, Robert; Zimmerman, Daniel; Triana, Santiago; Lathrop, Daniel

2012-11-01

Rotating fluid dynamics is key to our understanding of the Earth's atmosphere, oceans, and core, along with a plethora of astrophysical objects. Laboratory study of these natural systems often involves spinning experimental devices, which are assumed to tend to rigid rotation when unstirred. We present results showing that even at the tabletop scale, there is a measurable oscillatory flow driven by the precession of the experiment's axis as the earth rotates. We measure this flow in a rotating cylinder with an adjustable aspect ratio. The horizontal flow in the rotating frame is measured using particle tracking. The steady state is well-described by an inertial mode whose amplitude is maximum when the height to diameter ratio is 0.995, which matches theoretical predictions. We also quantify the resonant amplitude of the inertial mode in the cylinder and estimate the amplitude in other devices. We compare our results to similar studies done in spherical devices. [Triana et al., JGR, 117 (2012), B04103][Boisson et al., EPL, 98 (2012), 59002].

Gravitomagnetic Field of the Universe and Coriolis Force on the Rotating Earth

Science.gov (United States)

Veto, B.

2011-01-01

The Machian effect of distant masses of the universe in the frame of reference of the rotating Earth is demonstrated using the gravitomagnetic approach of general relativity. This effect appears in the form of a gravitomagnetic Lorentz force acting on moving bodies on the Earth. The gravitomagnetic field of the universe--deduced from a simple…

Effect of cerium substitution on microstructure and Faraday rotation of Ce{sub x}Y{sub 3-x}Fe{sub 5}O{sub 12} thin films

Energy Technology Data Exchange (ETDEWEB)

Shahrokhvand, S.M.; Mozaffari, M.; Rozatian, A.S.H. [University of Isfahan, Department of Physics, Faculty of Science, Isfahan (Iran, Islamic Republic of); Hamidi, S.M. [Shahid Beheshti University, Laser and Plasma Research Institute, Evin, Tehran (Iran, Islamic Republic of); Tehranchi, M.M. [Shahid Beheshti University, Laser and Plasma Research Institute, Evin, Tehran (Iran, Islamic Republic of); Shahid Beheshti University, Department of Physics, Evin, Tehran (Iran, Islamic Republic of)

2016-01-15

In this work, cerium-substituted yttrium iron garnet (Ce{sub x}Y{sub 3-x}Fe{sub 5}O{sub 12}, x = 0.25-1) targets were fabricated by conventional ceramic method at different temperatures, and their crystal structures were investigated by X-ray diffraction method. The results showed that the minimum calcining temperature required to get single-phase targets depends on x value and decreased by increasing x value. Then, thin films of the targets were deposited on GGG (444) single-crystal substrates by pulsed laser deposition technique. Based on the previous studies, preferred (444) oriented Ce{sub x}Y{sub 3-x}Fe{sub 5}O{sub 12} thin films were fabricated under optimum conditions. Faraday rotation of the thin films was measured at 635 nm wavelength, and the results showed that Faraday rotation and sensitivity constant increased by increasing x value. Scanning electron microscope images showed that by increasing x value, cracks on the thin films' surface increased. Atomic force microscopy images showed that the films have smooth surfaces and the surface roughness decreased by increasing the x value. (orig.)

Gravitomagnetic field of the universe and Coriolis force on the rotating Earth

International Nuclear Information System (INIS)

Veto, B

2011-01-01

The Machian effect of distant masses of the universe in the frame of reference of the rotating Earth is demonstrated using the gravitomagnetic approach of general relativity. This effect appears in the form of a gravitomagnetic Lorentz force acting on moving bodies on the Earth. The gravitomagnetic field of the universe-deduced from a simple model-exerts a gravitomagnetic Lorentz force on moving bodies, a force parallel to and with comparable strength to the Coriolis force observed on the rotating Earth. It seems after simple considerations that the Coriolis force happens to be the gravitomagnetic Lorentz force exerted by the mass of a black hole universe. The description of the phenomenon is simpler using the gravitomagnetic approach than the standard formulation of general relativity, so the method relying on gravitomagnetism is advisable in lectures intended for master's degree level physics students and advanced undergraduates.

Rotational Spectroscopy of the NH{sub 3}–H{sub 2} Molecular Complex

Energy Technology Data Exchange (ETDEWEB)

Surin, L. A.; Schlemmer, S. [I. Physikalisches Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne (Germany); Tarabukin, I. V. [Institute of Spectroscopy of Russian Academy of Sciences, Fizicheskaya Str. 5, 108840 Troitsk, Moscow, Russia (Russian Federation); Breier, A. A.; Giesen, T. F. [Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel (Germany); McCarthy, M. C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Avoird, A. van der, E-mail: surin@ph1.uni-koeln.de, E-mail: A.vanderAvoird@theochem.ru.nl [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

2017-03-20

We report the first high resolution spectroscopic study of the NH{sub 3}–H{sub 2} van der Waals molecular complex. Three different experimental techniques, a molecular beam Fourier transform microwave spectrometer, a millimeter-wave intracavity jet OROTRON spectrometer, and a submillimeter-wave jet spectrometer with multipass cell, were used to detect pure rotational transitions of NH{sub 3}–H{sub 2} in the wide frequency range from 39 to 230 GHz. Two nuclear spin species, ( o )-NH{sub 3}–( o )-H{sub 2} and ( p )-NH{sub 3}–( o )-H{sub 2}, have been assigned as carriers of the observed lines on the basis of accompanying rovibrational calculations performed using the ab initio intermolecular potential energy surface (PES) of Maret et al. The experimental spectra were compared with the theoretical bound state results, thus providing a critical test of the quality of the NH{sub 3}–H{sub 2} PES, which is a key issue for reliable computations of the collisional excitation and de-excitation of ammonia in the dense interstellar medium.

Fortnightly Earth Rotation, Ocean Tides, and Mantle Anelasticity

Science.gov (United States)

Ray, Richard D.; Egbert, Gary D.

2011-01-01

Sustained accurate measurements of earth rotation are one of the prime goals of Global Geodetic Observing System (GGOS). We here concentrate on the fortnightly (Mf) tidal component of earth-rotation data to obtain new results concerning anelasticity of the mantle at this period. The study comprises three parts: (1) a new determination of the Mf component of polar motion and length-of-day from a multi-decade time series of space-geodetic data; (2) the use of the polar-motion determination as one constraint in the development of a hydrodynamic ocean model of the Mf tide; and (3) the use of these results to place new constraints on mantle anelasticity. Our model of the Mf ocean tide assimilates more than fourteen years of altimeter data from the Topex/Poseidon and Jason-1 satellites. The polar motion data, plus tide-gauge data and independent altimeter data, give useful additional information, with only the polar motion putting constraints on tidal current velocities. The resulting ocean-tide model, plus the dominant elastic body tide, leaves a small residual in observed length-of-day caused by mantle anelasticity. The inferred effective tidal 0 of the anelastic body tide is 90 and is in line with a omega-alpha frequency dependence with alpha in the range 0.2--0.3.

Calcium substitution in rare-earth metal germanides with the hexagonal Mn{sub 5}Si{sub 3} structure type. structural characterization of the extended series RE{sub 5–x}Ca{sub x}Ge{sub 3} (RE=Rare-earth metal)

Energy Technology Data Exchange (ETDEWEB)

Suen, Nian-Tzu; Broda, Matthew; Bobev, Svilen, E-mail: bobev@udel.edu

2014-09-15

Reported are the synthesis and the structural characterization of an extended family of rare-earth metal–germanides with a general formula RE{sub 5–x}Ca{sub x}Ge{sub 3} (RE=Y, Ce–Nd, Sm, Gd–Tm and Lu; x<2). All twelve phases are isotypic, crystallizing with the Mn{sub 5}Si{sub 3} structure type (Pearson index hP16, hexagonal space group P6{sub 3}/mcm); they are the Ca-substituted variants of the corresponding RE{sub 5}Ge{sub 3} binaries. Across the series, despite some small variations in the Ca-uptake, the unit cell volumes decrease monotonically, following the lanthanide contraction. Temperature dependent DC magnetization measurements reveal paramagnetic behavior in the high temperature range, and the obtained effective moments are consistent with free-ion RE{sup 3+} ground state, as expected from prior studies of the binary RE{sub 5}Ge{sub 3} phases. The onset of magnetic ordering is observed in the low temperature range, and complex magnetic interactions (ferromagnetic/ferrimagnetic) can be inferred, different from the binary phases RE{sub 5}Ge{sub 3}, which are known as antiferromagnetic. In order to understand the role of Ca in the bonding, the electronic structures of the La{sub 5}Ge{sub 3} and the hypothetical compounds La{sub 2}Ca{sub 3}Ge{sub 3} and La{sub 3}Ca{sub 2}Ge{sub 3} with ordered metal atoms are compared and discussed. - Graphical abstract: The family of rare-earth metal–calcium–germanides with the general formula RE{sub 5–x}Ca{sub x}Ge{sub 3} (RE=Y, Ce–Nd, Sm, Gd–Tm and Lu) crystallize in the hexagonal space group P6{sub 3}/mcm (No. 193, Pearson symbol hP16) with a structure that is a variant of the Mn{sub 5}Si{sub 3} structure type. - Highlights: • The newly synthesized RE{sub 5–x}Ca{sub x}Ge{sub 3} (RE=Y, Ce–Nd, Sm, Gd–Tm and Lu) constitute an extended family. • The structure is a substitution variant of the hexagonal Mn{sub 5}Si{sub 3} structure type. • Ca-uptake is the highest in the early members, and

Short period tidal variations of earth rotation

Science.gov (United States)

Yoder, C. F.; Williams, J. G.; Parke, M. E.; Dickey, J. O.

1981-01-01

It is explained that the tidal deformation of the earth's polar moment of inertia by the moon and sun cause periodic variations in rotation. The short period oscillations give rise to a meter-sized, diurnal signature in the lunar laser ranging data obtained at McDonald Observatory. A solution is given for the scale parameter k/C at fortnightly and monthly tidal frequencies. The results are compared with those obtained by other investigators and with a theoretical estimate which includes the effect of oceans and a decoupled fluid core.

Solar rotation effects on the thermospheres of Mars and Earth.

Science.gov (United States)

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.

Spin rotation in ErGa{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Murasik, A. E-mail: amur@cyf.gov.pl; Czopnik, A. E-mail: czopnik@int.pan.wroc.pl; Keller, L. E-mail: lukas.keller@psi.ch; Fischer, P. E-mail: peter.fischer@psi.ch

2000-04-01

The magnetic phase diagram of ErGa{sub 3}, built up from bulk magnetisation data, shows in zero-applied magnetic field two successive transitions at T{sub 1}=2.6 and T{sub 2} congruent with 2.8 K, respectively. The magnetic ordering of ErGa{sub 3} examined by neutron diffraction, can be derived from the so-called {l_brace}((1)/(2)), ((1)/(2)), 0{r_brace} structure, i.e. one in which the successive antiparallel (1 1 0) sheets of spins have additionally superimposed on them a sinusoidal modulation parallel to the [1 0 0] axis. The temperature dependence of neutron diffraction diagrams studied on the single crystal, revealed in the range of (2.6-2.78) K an abrupt reorientation of the Er{sup 3+} spins from the nearly [1 1 0] direction, towards the [1 0 0] axis. In this way previously observed effect on the polycrystalline sample has been confirmed. This rotation can be attributed to the T{sub 1} transition found in the H-T magnetic phase diagram.

(abstract) Effect of Long Period Ocean Tides on the Earth's Rotation

Science.gov (United States)

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

1996-01-01

The second-degree zonal tide raising potential, which is responsible for tidal changes in the Earth's rotation rate and length-of-day, is symmetric about the polar axis and hence can excite the Earth's polar motion only through its action upon nonaxisymmetric features of the Earth such as the oceans. Ocean tidal excitation of polar motion in the diurnal and semidiurnal tidal bands has been previously detected and extensively examined. Here, the detection of ocean tidal excitation of polar motion in the long-period tidal band, specifically at the Mf' (13.63-day) and Mf (13.66-day) tidal frequencies, is reported.

Long-term changes in the rotation of the Earth: 700 B.C. to A.D. 1980

International Nuclear Information System (INIS)

Stephenson, F.R.

1984-01-01

Occultations of stars by the Moon, and solar and lunar eclipses are analysed for variations in the Earth's rotation over the past 2700 years. Although tidal braking provides the dominant, long-term torque, it is found that the rate of rotation does not decrease uniformly as would be expected if tidal friction were the only mechanism affecting the Earth's rotation. There are also non-tidal changes present that vary on timescales ranging from decades to millennia. The magnitudinal and temporal behaviour of these non-tidal variations are evaluated in this paper. (author)

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

Science.gov (United States)

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.

Ammonothermal synthesis of alkali-alkaline earth metal and alkali-rare earth metal carbodiimides. K{sub 5-x}M{sub x}(CN{sub 2}){sub 2+x}(HCN{sub 2}){sub 1-x} (M = Sr, Eu) and Na{sub 4.32}Sr{sub 0.68}(CN{sub 2}){sub 2.68}(HCN{sub 2}){sub 0.32}

Energy Technology Data Exchange (ETDEWEB)

Mallmann, Mathias; Haeusler, Jonas; Cordes, Niklas; Schnick, Wolfgang [Department of Chemistry, University of Munich (LMU) (Germany)

2017-12-13

Alkali-alkaline earth metal and alkali-rare earth metal carbodiimides, namely K{sub 5-x}M{sub x}(CN{sub 2}){sub 2+x}(HCN{sub 2}){sub 1-x} (x = 0 - 1) (M = Sr, Eu) and Na{sub 4.32}Sr{sub 0.68}(CN{sub 2}){sub 2.68}(HCN{sub 2}){sub 0.32}, were synthesized under ammonothermal conditions in high-pressure autoclaves. The structures of the three compounds can be derived from homeotypic K{sub 5}H(CN{sub 2}){sub 3} and Na{sub 5}H(CN{sub 2}){sub 3} by partial substitution of K{sup +} or Na{sup +}by Sr{sup 2+} or Eu{sup 2+}. The reactions were carried out in two step syntheses (T{sub 1} = 673 K, T{sub 2} = 823 K) starting from sodium or potassium azide, dicyandiamide and strontium or Eu(NH{sub 2}){sub 2}, respectively. The crystal structures were solved and refined from single-crystal X-ray diffraction data [K{sub 4.16}Sr{sub 0.84}(CN{sub 2}){sub 2.84}(HCN{sub 2}){sub 0.16}: space group Im3m (no. 229), a = 7.8304(5) Aa, Z = 2, R{sub 1} = 0.024, wR{sub 2} = 0.052; K{sub 4.40}Eu{sub 0.60}(CN{sub 2}){sub 2.60}(HCN{sub 2}){sub 0.40}: space group Im anti 3m (no. 229), a = 7.8502(6) Aa, Z = 2, R{sub 1} = 0.022, wR{sub 2} = 0.049]. In contrast to the potassium carbodiimides, the sodium-strontium carbodiimide was only synthesized as microcrystalline powder. The crystal structure was determined by powder X-ray diffraction and refined by the Rietveld method [Na{sub 4.32}Sr{sub 0.68}(CN{sub 2}){sub 2.68}(HCN{sub 2}){sub 0.32}: space group Im3m (no. 229), a = 7.2412(1) Aa, Z = 2, R{sub wp} = 0.050]. The presence of hydrogencyanamide units ([HNCN]{sup -}) next to carbodiimide units ([CN{sub 2}]{sup 2-}) in all compounds was confirmed by FT-IR spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Reconciling past changes in Earth's rotation with 20th century global sea-level rise: Resolving Munk's enigma.

Science.gov (United States)

Mitrovica, Jerry X; Hay, Carling C; Morrow, Eric; Kopp, Robert E; Dumberry, Mathieu; Stanley, Sabine

2015-12-01

In 2002, Munk defined an important enigma of 20th century global mean sea-level (GMSL) rise that has yet to be resolved. First, he listed three canonical observations related to Earth's rotation [(i) the slowing of Earth's rotation rate over the last three millennia inferred from ancient eclipse observations, and changes in the (ii) amplitude and (iii) orientation of Earth's rotation vector over the last century estimated from geodetic and astronomic measurements] and argued that they could all be fit by a model of ongoing glacial isostatic adjustment (GIA) associated with the last ice age. Second, he demonstrated that prevailing estimates of the 20th century GMSL rise (~1.5 to 2.0 mm/year), after correction for the maximum signal from ocean thermal expansion, implied mass flux from ice sheets and glaciers at a level that would grossly misfit the residual GIA-corrected observations of Earth's rotation. We demonstrate that the combination of lower estimates of the 20th century GMSL rise (up to 1990) improved modeling of the GIA process and that the correction of the eclipse record for a signal due to angular momentum exchange between the fluid outer core and the mantle reconciles all three Earth rotation observations. This resolution adds confidence to recent estimates of individual contributions to 20th century sea-level change and to projections of GMSL rise to the end of the 21st century based on them.

Superconducting properties of Ca{sub 1−x}RE{sub x}Fe{sub 2}As{sub 2} (RE: Rare Earths)

Energy Technology Data Exchange (ETDEWEB)

Tamegai, T., E-mail: tamegai@ap.t.u-tokyo.ac.jp [Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); JST, Transformative Research-Project on Iron Pnictides (TRIP), Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ding, Q.P. [Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); JST, Transformative Research-Project on Iron Pnictides (TRIP), Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ishibashi, T. [Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nakajima, Y. [Department of Applied Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); JST, Transformative Research-Project on Iron Pnictides (TRIP), Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2013-01-15

Highlights: ► Superconducting properties in rare-earth doped CaFe{sub 2}As{sub 2} single crystals are characterized. ► Sharp resistive transitions with small anisotropy parameter of ∼1.75 are observed. ► Average critical current density is much smaller than other iron-based superconductors. ► Magneto-optical imaging confirms very inhomogeneous superconducting state. -- Abstract: We have grown rare-earth doped CaFe{sub 2}As{sub 2} single crystals and characterized their normal and superconducting properties. Temperature dependence of resistivity and its absolute value suggest good metallic conduction, suppressing antiferromagnetic (AF) transition in the undoped sample. Hall coefficient shows little temperature dependence, consistent with the suppression AF state. Superconducting transitions characterized by resistivity drops in magnetic fields for both parallel to c-axis and ab-plane are reasonably sharp with a weak anisotropy parameter ∼1.75. Despite these observations, average critical current density estimated from the bulk magnetization is orders of magnitude smaller than other typical iron-based superconductors. Magneto-optical imaging confirms very inhomogeneous superconducting state.

Hexagonal perovskites with cationic vacancies. 32. Photoluminescence of trivalent rare earth in the systems Ba/sub 2-y/Sr/sub y/La/sub 2-x/RE/sub x/MgW/sub 2/vacantO/sub 12/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1982-06-01

In the series Ba/sub 2-y/Sr/sub y/La/sub 2-x/RE/sub x/MgW/sub 2/vacantO/sub 12/ the Ba/sup 2 +/ can be completely substituted by Sr/sup 2 +/. All compounds crystallize in the rhombohedral 12 L-type (space group R-3m; sequence (hhcc)/sub 3/). By doping the stacking polytypes with some of the trivalent rare earths efficient visible photoluminescence is obtained. The simultaneous incorporation of two different rare earth ions leads to two-color-phosphors, which, according to the excitation energy used, emit either mainly the typical spectrum from one or the other activator; the corresponding luminescence mechanism are discussed.

High frequency variations of Earth Rotation Parameters from GPS and GLONASS observations.

Science.gov (United States)

Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong

2015-01-28

The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future.

Galvanic vestibular stimulation combines with Earth-horizontal rotation in roll to induce the illusion of translation.

Science.gov (United States)

Schneider, Erich; Bartl, Klaus; Glasauer, Stefan

2009-05-01

Human head rotation in roll around an earth-horizontal axis constitutes a vestibular stimulus that, by its rotational component, acts on the semicircular canals (SCC) and that, by its tilt of the gravity vector, also acts on the otoliths. Galvanic vestibular stimulation (GVS) is thought to resemble mainly a rotation in roll. A superposition of sinusoidal GVS with a natural earth-horizontal roll movement was therefore applied in order to cancel the rotation effects and to isolate the otolith activation. By self-adjusting the amplitude and phase of GVS, subjects were able to minimize their sensation of rotation and to generate the perception of a linear translation. The final adjustments are in the range of a model that predicts SCC activation during natural rotations and GVS. This indicates that the tilt-translation ambiguity of the otoliths is resolved by SCC-otolith interaction. It is concluded that GVS might be able to cancel rotations in roll and that the residual tilt of the gravitoinertial force is possibly interpreted as a linear translation.

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate{sub N} simulation model

Energy Technology Data Exchange (ETDEWEB)

Guo Ruiying [Ministry of Education Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, No. 222 Tianshui Nanlu, Lanzhou 730000, Gansu Province (China); Nendel, Claas, E-mail: nendel@zalf.d [Institute for Landscape Systems Analysis, Leibniz-Center for Agricultural Landscape Research, Eberswalder Strasse 84, 15374 Muencheberg (Germany); Rahn, Clive [Warwick HRI, Wellesbourne CV35 9EF (United Kingdom); Jiang Chunguang; Chen Qing [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian, Beijing 100193 (China)

2010-06-15

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate{sub N} simulation model. EU-Rotate{sub N} was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter. - The EU-Rotate{sub N} model can satisfactorily simulate crop N uptake and N{sub min} dynamics in a typical greenhouse cucumber production system of North China

Decadal Cycles of Earth Rotation, Mean Sea Level and Climate, Excited by Solar Activity

Czech Academy of Sciences Publication Activity Database

Chapanov, Y.; Ron, Cyril; Vondrák, Jan

2017-01-01

Roč. 14, č. 2 (2017), s. 241-250 ISSN 1214-9705 R&D Projects: GA ČR GA13-15943S Institutional support: RVO:67985815 Keywords : Earth rotation * solar activity * mean sea level Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 0.699, year: 2016

Possible relationship between the Earth's rotation variations and geomagnetic field reversals over the past 510 Myr

OpenAIRE

Pacca, Igor G.; Frigo, Everton; Hartmann, Gelvam A.

2015-01-01

The Earth's rotation can change as a result of several internal and external processes, each of which is at a different timescale. Here, we present some possible connections between the Earth's rotation variations and the geomagnetic reversal frequency rates over the past 120 Myr. In addition, we show the possible relationship between the geomagnetic field reversal frequency and the δ18O oscillations. Because the latter reflects the glacial and interglacial periods, we hypothesize that it can...

Structural, electronic properties and enhancement of electrical polarization in Er{sub 2}NiMnO{sub 6}/La{sub 2}NiMnO{sub 6} superlattice by first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Lu, Haipeng; Deng, Longjiang [National Engineering Research Center of Electromagnetic Radiation Control Materials, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Sun, Xun, E-mail: sunxunphy@hotmail.com; Hou, Zhihua; Yang, Wen; Wang, Siyuan; Xie, Jianliang [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China)

2016-03-15

Employing first-principles calculations, structural, electronic properties of new multiferroic material Er{sub 2}NiMnO{sub 6}/La{sub 2}NiMnO{sub 6} perovskite superlattice are investigated. This structure is computed as monoclinic phase with obvious distortion. The average in-plane anti-phase rotation angle, average out-of-plane in-phase rotation angle and other microscopic features are reported in this paper. Ni and Mn are found in this superlattice that stay high spin states. These microscopic properties play important roles in multiferroic properties. Based on these microscopic features, the relationship between the direction of spontaneous polarization and the order of substitution in neighboring A-O layers is explained. Finally, we try to enhance the electrical polarization magnitude by 32% by altering the previous superlattice as LaEr{sub 2}NiMnO{sub 7} structure. Our results show that both repulsion force of A site rare earth ions and the arrangement of B site ions can exert influences on spontaneous polarization.

Effects of Zonal Deformations and the Earth's Rotation Rate Variations on Precession-Nutation

National Research Council Canada - National Science Library

Lambert, S

2004-01-01

.... This paper considers the coupling effects between the axial and the equatorial components of the Earth's rotation vector in the dynamical equations, and the effects of the second order lunisolar...

Microstructure study of the rare-earth intermetallic compounds R<sub>5sub>(Si_xGe>1-xsub>)>4sub> and R<sub>5sub>(Si_xGe>1-xsub>)>3sub>

Energy Technology Data Exchange (ETDEWEB)

Cao, Qing [Iowa State Univ., Ames, IA (United States)

2012-01-01

The unique combination of magnetic properties and structural transitions exhibited by many members of the R<sub>5sub>(Si_xGe>1-xsub>)>4sub> family (R = rare earths, 0 ≤ x ≤ 1) presents numerous opportunities for these materials in advanced energy transformation applications. Past research has proven that the crystal structure and magnetic ordering of the R<sub>5sub>(Si_xGe>1-xsub>)>4sub> compounds can be altered by temperature, magnetic field, pressure and the Si/Ge ratio. Results of this thesis study on the crystal structure of the Er<sub>5sub>Si>4sub> compound have for the first time shown that the application of mechanical forces (i.e. shear stress introduced during the mechanical grinding) can also result in a structural transition from Gd<sub>5sub>Si>4sub>-type orthorhombic to Gd<sub>5sub>Si>2sub>Ge>2sub>-type monoclinic. This structural transition is reversible, moving in the opposite direction when the material is subjected to low-temperature annealing at 500 °C.

Intercomparison of lunar laser and traditional determinations of earth rotation

Science.gov (United States)

Fliegel, H. F.; Dickey, J. O.; Williams, J. G.

1982-01-01

Since August, 1969, ranges to one or more retroreflector arrays on the lunar surface have been measured by means of a laser procedure. Analysis of these measurements improves determination, not only of the orbit and librations of the moon, but also of the rotational parameters of the earth, including the X and Y coordinates of the terrestrial pole, and the true rotational angle of the earth with respect to atomic or to broadcast time. The considered approach for deriving the Universal Time 1 (UT1) involves two steps. During the first step the parameters of the lunar orbit and librations are solved along with the coordinates of the retroreflectors on the moon and of the observatory. Improved values of the Universal Time 0 (UT0) and range corrections at the observatory are obtained in the second step. Attention is given to lunar laser ranging (LLR), raw data in UT1, an harmonic analysis of the LLR UT1 data, and data obtained in 1980. The results provide UT1 with an accuracy of a factor of 2 or more better than was previously available from conventional astrometric data.

Lateral Earth Pressure behind Walls Rotating about Base considering Arching Effects

Directory of Open Access Journals (Sweden)

Dong Li

2014-01-01

Full Text Available In field, the earth pressure on a retaining wall is the common effect of kinds of factors. To figure out how key factors act, it has taken into account the arching effects together with the contribution from the mode of displacement of a wall to calculate earth pressure in the proposed method. Based on Mohr circle, a conversion factor is introduced to determine the shear stresses between artificial slices in soil mass. In the light of this basis, a modified differential slices solution is presented for calculation of active earth pressure on a retaining wall. Comparisons show that the result of proposed method is identical to observations from model tests in prediction of lateral pressures for walls rotating about the base.

How to test the special theory of relativity on rotating earth

International Nuclear Information System (INIS)

Abolghasem, H.; Khadjehpoor, M.R.; Mansouri, R.

1988-02-01

In the framework of a one parameter test theory of special relativity, the difference between Transport- and Einstein synchronization on the rotating earth is calculated. For the special theory of relativity this difference vanishes. Therefore, experiments in which these synchronization procedures are compared, test the special theory of relativity. (author). 8 refs

Effects of Long Period Ocean Tides on the Earth's Rotation

Science.gov (United States)

Gross, Richard S.; Chao, Ben F.; Desai, Shailen D.

1996-01-01

The spectra of polar motion excitation functions exhibit enhanced power in the fortnightly tidal band. This enhanced power is attributed to ocean tidal excitation. Ocean tide models predict polar motion excitation effects that differ with each other, and with observations, by factors as large as 2-3. There is a need for inproved models for the effect of long-period ocean tides on Earth's rotation.

Semiconductor sensor for optically measuring polarization rotation of optical wavefronts using rare earth iron garnets

Science.gov (United States)

Duncan, Paul G.

2002-01-01

Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.

Muon-spin rotation studies of the flux lattice in {kappa}-(BEDT-TTF){sub 2}Cu(SCN){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Lee, S.L. [Saint Andrews Univ. (United Kingdom). Sch. of Phys. and Astron.; Blundell, S.J. [Oxford Univ. (United Kingdom). Dept. of Physics; Pratt, F.L. [RIKEN-RAL, Didcot (United Kingdom); Pattenden, P.A. [Oxford Univ. (United Kingdom). Dept. of Physics; Forgan, E.M. [Birmingham Univ. (United Kingdom). School of Physics and Space Research; Sasaki, T. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research; Aegerter, C.M. [Zurich Univ. (Switzerland). Inst. fuer Physik; Hunt, M. [Zurich Univ. (Switzerland). Inst. fuer Physik; Chow, K.H. [Oxford Univ. (United Kingdom). Dept. of Physics; Hayes, W. [Oxford Univ. (United Kingdom). Dept. of Physics; Singleton, J. [Oxford Univ. (United Kingdom). Dept. of Physics; Keller, H. [Zurich Univ. (Switzerland). Inst. fuer Physik; Savic, I.M. [Zurich Univ. (Switzerland). Inst. fuer Physik

1997-02-15

Muon spin rotation ({mu}SR) studies of the vortex lattice in the superconductor {kappa}-(BEDT-TTF){sub 2}Cu(SCN){sub 2} have revealed a crossover from a quasi-2d to a vortex-line lattice structure for fields below a characteristic field B{sub cr}. The {mu}SR-lineshapes measured from the vortex-line lattice have allowed a re-evaluation of the in-plane penetration depth. (orig.)

Mass-radius relations and core-envelope decompositions of super-Earths and sub-Neptunes

Energy Technology Data Exchange (ETDEWEB)

Howe, Alex R.; Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States); Verne, Wesley, E-mail: arhowe@astro.princeton.edu, E-mail: burrows@astro.princeton.edu [Department of Computer Science, Princeton University, Princeton, NJ 08544 (United States)

2014-06-01

Many exoplanets have been discovered with radii of 1-4 R {sub ⊕}, between that of Earth and Neptune. A number of these are known to have densities consistent with solid compositions, while others are 'sub-Neptunes' likely to have significant H{sub 2}-He envelopes. Future surveys will no doubt significantly expand these populations. In order to understand how the measured masses and radii of such planets can inform their structures and compositions, we construct models both for solid layered planets and for planets with solid cores and gaseous envelopes, exploring a range of core masses, H{sub 2}-He envelope masses, and associated envelope entropies. For planets in the super-Earth/sub-Neptune regime for which both radius and mass are measured, we estimate how each is partitioned into a solid core and gaseous envelope, associating a specific core mass and envelope mass with a given exoplanet. We perform this decomposition for both ''Earth-like'' rock-iron cores and pure ice cores, and find that the necessary gaseous envelope masses for this important sub-class of exoplanets must range very widely from zero to many Earth masses, even for a given core mass. This result bears importantly on exoplanet formation and envelope evaporation processes.

Effect of rare-earth additions on the structure and dielectric energy storage properties of Ba{sub x}Sr{sub 1-x}TiO{sub 3}-based barium boronaluminosilicate glass-ceramics

Energy Technology Data Exchange (ETDEWEB)

Xiu, Shaomei; Xiao, Shi; Zhang, Wenqin; Xue, Shuangxi; Shen, Bo, E-mail: shenbo@tongji.edu.cn; Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn

2016-06-15

Ba{sub x}Sr{sub 1-x}TiO{sub 3}-based barium boroaluminosilicate (BST-BBAS) glass-ceramics added with La{sub 2}O{sub 3}, Gd{sub 2}O{sub 3} and Yb{sub 2}O{sub 3} were fabricated through the melting method followed by controlled crystallization, respectively. The X-ray diffraction and the field emission scanning electron microscopy were investigated the phase composition and microstructure for the BST-BBAS glass-ceramics added with rare-earth additions, then the temperature-dependent dielectric properties and the voltage-withstand measurements were applied to study the effect of rare-earth additions on the dielectric energy storage density. These results show that the certain content of rare-earth additions can optimize the microstructure and phase structure effectively. And with the decrease of ionic radiuses of rare-earth elements, the microstructure of the glass-ceramics become more uniform. When added with 0.5 mol% Yb{sup 3+}, the theoretical energy storage density of the BST-BBAS glass-ceramics gets the largest value of 3.5 J/cm{sup 3} which is about 1.8 times compared to the undoped one. - Highlights: • A certain content of Yb{sub 2}O{sub 3} can restrain the formation of BaSi{sub 2}O{sub 5}and SiO{sub 2} phases. • The addition of rare earth can optimize the microstructure. • With 0.5 mol% Yb{sup 3+}, the dielectric energy storage density got the largest value of 3.5 J/cm{sup 3}.

A global dataset of sub-daily rainfall indices

Science.gov (United States)

Fowler, H. J.; Lewis, E.; Blenkinsop, S.; Guerreiro, S.; Li, X.; Barbero, R.; Chan, S.; Lenderink, G.; Westra, S.

2017-12-01

It is still uncertain how hydrological extremes will change with global warming as we do not fully understand the processes that cause extreme precipitation under current climate variability. The INTENSE project is using a novel and fully-integrated data-modelling approach to provide a step-change in our understanding of the nature and drivers of global precipitation extremes and change on societally relevant timescales, leading to improved high-resolution climate model representation of extreme rainfall processes. The INTENSE project is in conjunction with the World Climate Research Programme (WCRP)'s Grand Challenge on 'Understanding and Predicting Weather and Climate Extremes' and the Global Water and Energy Exchanges Project (GEWEX) Science questions. A new global sub-daily precipitation dataset has been constructed (data collection is ongoing). Metadata for each station has been calculated, detailing record lengths, missing data, station locations. A set of global hydroclimatic indices have been produced based upon stakeholder recommendations including indices that describe maximum rainfall totals and timing, the intensity, duration and frequency of storms, frequency of storms above specific thresholds and information about the diurnal cycle. This will provide a unique global data resource on sub-daily precipitation whose derived indices will be freely available to the wider scientific community.

ExoMol molecular line lists - XVII. The rotation-vibration spectrum of hot SO<sub>3sub>

DEFF Research Database (Denmark)

Underwood, Daniel S.; Yurchenko, Sergei N.; Tennyson, Jonathan

2016-01-01

Sulphur trioxide (SO3) is a trace species in the atmospheres of the Earth and Venus, as well as being an industrial product and an environmental pollutant. A variational line list for 32S16O3, named UYT2, is presented containing 21 billion vibration-rotation transitions. UYT2 can be used to model...

Effect of rare-earth ion size on local electron structure in RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (R = Tm, Dy, Gd, Eu, Nd and Y) superconductors: A positron study

Energy Technology Data Exchange (ETDEWEB)

Chen Zhenping [Department of Technology and Physics, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, Henan 450002 (China)]. E-mail: czhping@zzuli.edu.cn; Zhang Jincang [Department of Physics, Shanghai University, Shanghai 200436 (China); Su Yuling [Department of Technology and Physics, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, Henan 450002 (China); Xue Yuncai [Department of Technology and Physics, Zhengzhou University of Light Industry, 5 Dongfeng Road, Zhengzhou, Henan 450002 (China); Cao Shixun [Department of Physics, Shanghai University, Shanghai 200436 (China)

2006-02-15

The effects of rare-earth ionic size on the local electron structure, lattice parameters and superconductivity have been investigated by positron annihilation technique (PAT) and related experiments for RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (R = Tm, Dy, Gd, Eu, Nd and Y) superconductors. The local electron density n {sub e} is evaluated as a function of the rare-earth radius. The results show that both the bulk-lifetime {tau} {sub B} and the defect lifetime {tau} {sub 2} increase with increasing rare-earth ionic radius, while the local electron density n {sub e} decrease with increasing rare-earth ionic radius. These results prove that the changes of n {sub e}, the degree of orthorhombic distortion and the coupling between the Cu-O chains and the CuO{sub 2} planes all have an effect on the superconductivity of RBa{sub 2}Cu{sub 3}O{sub 7-{delta}} systems.

Effect of Earth's rotation on the quantum mechanical phase of the neutron

International Nuclear Information System (INIS)

Werner, S.A.; Staudenmann, J.; Colella, R.

1979-01-01

Using a neutron interferometer of the type first developed by Bonse and Hart for x rays, we have observed the effect of Earth's rotation on the phase of the neutron wave function. This experiment is the quantum mechanical analog of the optical interferometry observations of Michelson, Gale, and Pearson

Rotationally inelastic scattering of methyl radicals with Ar and N{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Tkáč, Ondřej; Orr-Ewing, Andrew J., E-mail: a.orr-ewing@bristol.ac.uk [School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS (United Kingdom); Ma, Qianli; Dagdigian, Paul J., E-mail: pjdagdigian@jhu.edu [Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218-2685 (United States); Stei, Martin [Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria)

2015-01-07

The rotationally inelastic scattering of methyl radical with Ar and N{sub 2} is examined at collision energies of 330 ± 25 cm{sup −1} and 425 ± 50 cm{sup −1}, respectively. Differential cross sections (DCSs) were measured for different final n′ rotational levels (up to n′ = 5) of the methyl radicals, averaged over k′ sub-levels, using a crossed molecular beam machine with velocity map imaging. For Ar as a collision partner, we present a newly constructed ab initio potential energy surface and quantum mechanical scattering calculations of state-resolved DCSs. These computed DCSs agree well with the measurements. The DCSs for both Ar and N{sub 2} collision partners are strongly forward peaked for all spectroscopic lines measured. For scattering angles below 60°, the theoretical CD{sub 3}–Ar DCSs show diffraction oscillations that become less pronounced as n′ increases, but these oscillations are not resolved experimentally. Comparisons are drawn with our recently reported DCSs for scattering of methyl radicals with He atoms.

On the Long-Term "Hesitation Waltz" Between the Earth's Figure and Rotation Axes

Science.gov (United States)

Couhert, A.; Mercier, F.; Bizouard, C.

2017-12-01

The principal figure axis of the Earth refers to its axis of maximum inertia. In the absence of external torques, the latter should closely coincide with the rotation pole, when averaged over many years. However, because of tidal and non-tidal mass redistributions within the Earth system, the rotational axis executes a circular motion around the figure axis essentially at seasonal time scales. In between, it is not clear what happens at decadal time spans and how well the two axes are aligned. The long record of accurate Satellite Laser Ranging (SLR) observations to Lageos makes possible to directly measure the long time displacement of the figure axis with respect to the crust, through the determination of the degree 2 order 1 geopotential coefficients for the 34-year period 1983-2017. On the other hand, the pole coordinate time series (mainly from GNSS and VLBI data) yield the motion of the rotation pole with even a greater accuracy. This study is focused on the analysis of the long-term behavior of the two time series, as well as the derivation of possible explanations for their discrepancies.

Temperature-induced spin reorientation and magnetization jump of rare-earth orthoferrite Ho{sub 0.5}Pr{sub 0.5}FeO{sub 3} single crystal

Energy Technology Data Exchange (ETDEWEB)

Wang, Guohua; Zhao, Weiyao; Cao, Yiming; Kang, Baojuan [Department of Physics, and International Center of Quantum and Molecular Structures, Shanghai University, Shanghai 200444 (China); Zhang, Jincang [Department of Physics, and International Center of Quantum and Molecular Structures, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444 (China); Ren, Wei, E-mail: renwei@shu.edu.cn [Department of Physics, and International Center of Quantum and Molecular Structures, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444 (China); Cao, Shixun, E-mail: sxcao@shu.edu.cn [Department of Physics, and International Center of Quantum and Molecular Structures, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444 (China)

2016-07-25

We report temperature-induced spin reorientation and magnetization jump effects in the rare earth (RE) orthoferrite Ho{sub 0.5}Pr{sub 0.5}FeO{sub 3} single crystal. The single crystal of about 6 mm in diameter and 50 mm in length was successfully grown by optical floating zone method. Both X-ray diffraction and Laue photograph confirmed the homogeneity and high quality of the crystal. Magnetic properties of Ho{sub 0.5}Pr{sub 0.5}FeO{sub 3} single crystal are studied over a wide temperature range from 2 to 300 K. Spin reorientation transition from Γ{sub 2} to Γ{sub 4} phase is observed in the temperature range of 75–90 K. At lower temperature, the Ho{sub 0.5}Pr{sub 0.5}FeO{sub 3} shows an abrupt jump of magnetization along the a-axis, which occurs only in the field-cooling process, and is sensitive to external applied magnetic field. By analyzing the jump temperature and magnitude of the magnetization, we conclude that it is caused by the spin reversal of the rare earth ions. The isothermal magnetization versus field hysteresis loop measurements along a axis explain the spin configuration variation from 3 K to 60 K. - Highlights: • Ho{sub 0.5}Pr{sub 0.5}FeO{sub 3} single crystal was grown by optical floating zone method. • It shows an abrupt jump of magnetization along a axis at low temperature. • The jump height and temperature is sensitive to external applied magnetic field. • It is attributed to the spin reversal of the rare earth ions.

Episodic Spin-up and Spin-down Torque on Earth

Science.gov (United States)

Slabinski, Victor J.; Mendonca, Antonio A.

2018-04-01

Variations in Earth rotation angle are traditionally expressed by the time difference (ΔT=TT-UT1) between Terrestrial Time (TT) as told by atomic clocks and Universal Time UT1, the time variable used by the Earth-rotation formula. A plot of ΔT versus TT over the past 160 years shows a continuous curve with approximate straight-line segments with different spans of order ~20 years. Removing the tidal and seasonal variations from the data gives these line segments which represent the “decadal variations” in Earth rotation.The slope of a straight-line segment is proportional to the departure of Earth rotation rate from a reference value at the time. The change in slope over the relatively short time between segments indicates an episodic spin-up or spin-down in Earth rotation. The daily combination of VLBI, SLR, and other modern data available since 1973 gives us accurate, daily values of ΔT and the corresponding LOD (Length Of Day) values during these episodes. These allow us to determine the rotational acceleration occurring then.The three largest spin-speed changes found during the VLBI era have the following characteristics:Episode _____________ Duration__ ΔLOD__LOD Rate1983 Dec 30-1984 Jan 28 ... 29 d ...-0.65 ms ..-8.3 ms/y ..........spin-up1989 Mar 15-1989 May 23 ...69 d ....0.68 .......+3.6 ..............spin-down1994 Jan 21-2001 Apr 01 ... 6.5 y ...-2.2 .........-0.36 ..extended spin-upFor the first two episodes listed, we find the acceleration grows from zero (or at least a relatively small value) to its extreme value in ~1 day, stays approximately constant at this value for 29 or 69 days, and then decays back to zero over ~1 day. The acceleration, while it occurs, gives an LOD rate much greater than the 0.02 ms/y rate from tidal friction.The third episode shows that occasionally a several-year-long episode occurs. The acceleration magnitude is smaller but can make a larger total change in LOD (and spin rate). Tidal friction requires >100 y to equal

GENERAL THEORY OF THE ROTATION OF THE NON-RIGID EARTH AT THE SECOND ORDER. I. THE RIGID MODEL IN ANDOYER VARIABLES

International Nuclear Information System (INIS)

Getino, J.; Miguel, D.; Escapa, A.

2010-01-01

This paper is the first part of an investigation where we will present an analytical general theory of the rotation of the non-rigid Earth at the second order, which considers the effects of the interaction of the rotation of the Earth with itself, also named as the spin-spin coupling. Here, and as a necessary step in the development of that theory, we derive complete, explicit, analytical formulae of the rigid Earth rotation that account for the second-order rotation-rotation interaction. These expressions are not provided in this form by any current rigid Earth model. Working within the Hamiltonian framework established by Kinoshita, we study the second-order effects arising from the interaction of the main term in the Earth geopotential expansion with itself, and with the complementary term arising when referring the rotational motion to the moving ecliptic. To this aim, we apply a canonical perturbation method to solve analytically the canonical equations at the second order, determining the expressions that provide the nutation-precession, the polar motion, and the length of day. In the case of the motion of the equatorial plane, nutation-precession, we compare our general approach with the particular study for this motion developed by Souchay et al., showing the existence of new terms whose numerical values are within the truncation level of 0.1 μas adopted by those authors. These terms emerge as a consequence of not assuming in this work the same restrictive simplifications taken by Souchay et al. The importance of these additional contributions is that, as the analytical formulae show, they depend on the Earth model considered, in such a way that the fluid core resonance could amplify them significatively when extending this theory to the non-rigid Earth models.

Signature effects in 2qp bands of doubly even rare-earth nuclei

Energy Technology Data Exchange (ETDEWEB)

Kalra, Kawalpreet [Amity University, AUUP, Department of Physics, Amity Institute of Applied Sciences (AIAS), Noida (India); Goel, Alpana [Amity University, AUUP, Amity Institute of Nuclear Science and Technology (AINST), Noida (India); Jain, A.K. [Indian Institute of Technology (IIT), Department of Physics, Roorkee (India)

2016-12-15

The two-quasiparticle rotational bands in deformed doubly even nuclei in the rare-earth 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 {sup 162}{sub 66}Dy, {sup 170}{sub 70}Yb and {sup 170}{sub 74}W in even-even nuclei. Two quasiparticle plus rotor model (TQPRM) calculations are carried out to explain the reverse pattern of signature in {sup 170}{sub 74}W for the rotational band having configuration {(h_1_1_/_2)_p x (d_5_/_2)_p}. (orig.)

Propagation Velocity of Solid Earth Tides

Science.gov (United States)

Pathak, S.

2017-12-01

One of the significant considerations in most of the geodetic investigations is to take into account the outcome of Solid Earth tides on the location and its consequent impact on the time series of coordinates. In this research work, the propagation velocity resulting from the Solid Earth tides between the Indian stations is computed. Mean daily coordinates for the stations have been computed by applying static precise point positioning technique for a day. The computed coordinates are used as an input for computing the tidal displacements at the stations by Gravity method along three directions at 1-minute interval for 24 hours. Further the baseline distances are computed between four Indian stations. Computation of the propagation velocity for Solid Earth tides can be done by the virtue of study of the concurrent effect of it in-between the stations of identified baseline distance along with the time consumed by the tides for reaching from one station to another. The propagation velocity helps in distinguishing the impact at any station if the consequence at a known station for a specific time-period is known. Thus, with the knowledge of propagation velocity, the spatial and temporal effects of solid earth tides can be estimated with respect to a known station. As theoretically explained, the tides generated are due to the position of celestial bodies rotating about Earth. So the need of study is to observe the correlation of propagation velocity with the rotation speed of the Earth. The propagation velocity of Solid Earth tides comes out to be in the range of 440-470 m/s. This velocity comes out to be in a good agreement with the Earth's rotation speed.

Residual rotational set-up errors after daily cone-beam CT image guided radiotherapy of locally advanced cervical cancer

International Nuclear Information System (INIS)

Laursen, Louise Vagner; Elstrøm, Ulrik Vindelev; Vestergaard, Anne; Muren, Ludvig P.; Petersen, Jørgen Baltzer; Lindegaard, Jacob Christian; Grau, Cai; Tanderup, Kari

2012-01-01

Purpose: Due to the often quite extended treatment fields in cervical cancer radiotherapy, uncorrected rotational set-up errors result in a potential risk of target miss. This study reports on the residual rotational set-up error after using daily cone beam computed tomography (CBCT) to position cervical cancer patients for radiotherapy treatment. Methods and materials: Twenty-five patients with locally advanced cervical cancer had daily CBCT scans (650 CBCTs in total) prior to treatment delivery. We retrospectively analyzed the translational shifts made in the clinic prior to each treatment fraction as well as the residual rotational errors remaining after translational correction. Results: The CBCT-guided couch movement resulted in a mean translational 3D vector correction of 7.4 mm. Residual rotational error resulted in a target shift exceeding 5 mm in 57 of the 650 treatment fractions. Three patients alone accounted for 30 of these fractions. Nine patients had no shifts exceeding 5 mm and 13 patients had 5 or less treatment fractions with such shifts. Conclusion: Twenty-two of the 25 patients have none or few treatment fractions with target shifts larger than 5 mm due to residual rotational error. However, three patients display a significant number of shifts suggesting a more systematic set-up error.

Thermochemistry of rare earth doped uranium oxides Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} (Ln = La, Y, Nd)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lei; Navrotsky, Alexandra, E-mail: anavrotsky@ucdavis.edu

2015-10-15

Lanthanum, yttrium, and neodymium doped uranium dioxide samples in the fluorite structure have been synthesized, characterized in terms of metal ratio and oxygen content, and their enthalpies of formation measured by high temperature oxide melt solution calorimetry. For oxides doped with 10–50 mol % rare earth (Ln) cations, the formation enthalpies from constituent oxides (LnO{sub 1.5}, UO{sub 2} and UO{sub 3} in a reaction not involving oxidation or reduction) become increasingly exothermic with increasing rare earth content, while showing no significant dependence on the varying uranium oxidation state. The oxidation enthalpy of Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} is similar to that of UO{sub 2} to UO{sub 3} for all three rare earth doped systems. Though this may suggest that the oxidized uranium in these systems is energetically similar to that in the hexavalent state, thermochemical data alone can not constrain whether the uranium is present as U{sup 5+}, U{sup 6+}, or a mixture of oxidation states. The formation enthalpies from elements calculated from the calorimetric data are generally consistent with those from free energy measurements. - Highlights: • We synthesize, characterize Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} solid solutions (Ln = La, Y, Nd). • Formation enthalpies become more exothermic with increasing rare earth content. • Oxidation enthalpy of Ln{sub x}U{sub 1−x}O{sub 2−0.5x+y} is similar to that of UO{sub 2} to UO{sub 3}. • Direct calorimetric measurements are in good agreement with free energy data.

Axis of eye rotation changes with head-pitch orientation during head impulses about earth-vertical.

Science.gov (United States)

Migliaccio, Americo A; Schubert, Michael C; Clendaniel, Richard A; Carey, John P; Della Santina, Charles C; Minor, Lloyd B; Zee, David S

2006-06-01

The goal of this study was to assess how the axis of head rotation, Listing's law, and eye position influence the axis of eye rotation during brief, rapid head rotations. We specifically asked how the axis of eye rotation during the initial angular vestibuloocular reflex (VOR) changed when the pitch orientation of the head relative to Earth-vertical was varied, but the initial position of the eye in the orbit and the orientation of Listing's plane with respect to the head were fixed. We measured three-dimensional eye and head rotation axes in eight normal humans using the search coil technique during head-and-trunk (whole-body) and head-on-trunk (head-only) "impulses" about an Earth-vertical axis. The head was initially oriented at one of five pitch angles (30 degrees nose down, 15 degrees nose down, 0 degrees, 15 degrees nose up, 30 degrees nose up). The fixation target was always aligned with the nasooccipital axis. Whole-body impulses were passive, unpredictable, manual, rotations with peak-amplitude of approximately 20 degrees , peak-velocity of approximately 80 degrees /s, and peak-acceleration of approximately 1000 degrees /s2. Head-only impulses were also passive, unpredictable, manual, rotations with peak-amplitude of approximately 20 degrees , peak-velocity of approximately 150 degrees /s, and peak-acceleration of approximately 3000 degrees /s2. During whole-body impulses, the axis of eye rotation tilted in the same direction, and by an amount proportional (0.51 +/- 0.09), to the starting pitch head orientation (P rotation could be predicted from vectorial summation of the gains (eye velocity/head velocity) obtained for rotations about the pure yaw and roll head axes. Thus, even when the orientation of Listing's plane and eye position in the orbit are fixed, the axis of eye rotation during the VOR reflects a compromise between the requirements of Listing's law and a perfectly compensatory VOR.

A basic study on capture and solidification of rare earth nuclide (Nd) in LiCl-KCl eutectic salt using an inorganic composite with Li{sub 2}OAl{sub 2}O{sub 3}- SiO{sub 2}-B{sub 2}O{sub 3} systems

Energy Technology Data Exchange (ETDEWEB)

Kim, Na Young; Eum, Hee Chul; Park, Hwan Seo; Ahn, Do Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

The pyroprocessing of spent nuclear fuel generates LiCl-KCl eutectic waste salt containing radioactive rare earth nuclides. It is necessary to develop a simple process for the treatment of LiCl-KCl eutectic waste in a hot-cell facility. In this study, capture and solidification of a rare earth nuclide (Nd) in LiCl-KCl eutectic salt using an inorganic composite with a Li{sub 2}OAl{sub 2}O{sub 3}- SiO{sub 2}-B{sub 2}O{sub 3} system was conducted to simplify the existing separation and solidification process of rare earth nuclides in LiCl-KCl eutectic waste salt from the pyroprocessing of spent nuclear fuel. More than 98wt% of Nd in LiCl-KCl eutectic salt was captured when the mass ratio of the composite was 0.67 over NdCl3 in the eutectic salt. The content of Nd{sub 2}O{sub 3} in the Nd captured-composite reached about 50wt%, and this composite was directly fabricated into a homogeneous and chemical resistant glass waste in a monolithic form. These results will be utilized in designing a process to simplify the existing separation and solidification process.

Structure, electronic properties, luminescence and chromaticity investigations of rare earth doped KMgBO{sub 3} phosphors

Energy Technology Data Exchange (ETDEWEB)

Zheng, Jianghui; Cheng, Qijin [School of Energy Research, Xiamen University, Xiamen 361005 (China); Wu, Shunqing [Department of Physics, Xiamen University, Xiamen, 361005 (China); Zhuang, Yixi [College of Materials, Xiamen University, Xiamen 361005 (China); Guo, Ziquan; Lu, Yijun [Department of Electronic Science, Fujian Engineering Research Center for Solid-state Lighting, Xiamen University, Xiamen 361005 (China); Chen, Chao, E-mail: cchen@xmu.edu.cn [School of Energy Research, Xiamen University, Xiamen 361005 (China); Department of Physics, Xiamen University, Xiamen, 361005 (China); Department of Electronic Science, Fujian Engineering Research Center for Solid-state Lighting, Xiamen University, Xiamen 361005 (China)

2015-09-01

In this work, the optimization of the geometry and the electronic properties of the host matrix KMgBO{sub 3} were investigated using density functional theory, and the comprehensive photoluminescence and chromaticity properties on five rare earth ion-doped (RE = Ce{sup 3+}, Tm{sup 3+}, Tb{sup 3+}, Eu{sup 3+}, Dy{sup 3+}) KMgBO{sub 3} phosphors were also studied. By introducing RE ions into the KMgBO{sub 3} host, excellent purple, blue, green, red and white emitting light could be obtained under the near-ultraviolet light excitation. The results suggest that rare earth doped KMgBO{sub 3} phosphors are potential luminescence materials for the application in the near-ultraviolet white light-emitting diodes. - Highlights: • The electronic properties of the host matrix KMgBO{sub 3} were investigated. • The PL properties on rare earth ions doped KMgBO{sub 3} phosphors were studied. • The chromaticity properties on rare earth ions doped KMgBO{sub 3} samples were studied. • Tm{sup 3+} and Eu{sup 3+} doped KMgBO{sub 3} samples show higher color purity than commercial phosphors.

Project of a laser gyroscope to determine continuously the Earth's rotation.

Science.gov (United States)

Blinov, N. S.; Zharov, V. E.; Sazhin, M. V.; Fedoseev, E. N.; Vlasov, B. I.; Rusakov, V. K.

The Time Service of the Sternberg State Astronomical Institute together with specialists of VNIIFTRI began to work at the project of the laser gyroscope to determine continuously the Earth's rotation. It is assumed to measure both the high-frequency variations with periods of 100 - 1000 sec and the low-frequency variations with periods of a few days. It gives the opportunity to combine these data with the VLBI data.

Study of Mn dissolution from LiMn{sub 2}O{sub 4} spinel electrodes using rotating ring-disk collection experiments

Energy Technology Data Exchange (ETDEWEB)

Wang, Li-Fang; Ou, Chin-Ching; Striebel, Kathryn A.; Chen, Jenn-Shing

2003-07-01

The goal of this research was to measure Mn dissolution from a thin porous spinel LiMn{sub 2}O{sub 4} electrode by rotating ring-disk collection experiments. The amount of Mn dissolution from the spinel LiMn{sub 2}O{sub 4} electrode under various conditions was detected by potential step chronoamperometry. The concentration of dissolved Mn was found to increase with increasing cycle numbers and elevated temperature. The dissolved Mn was not dependent on disk rotation speed, which indicated that the Mn dissolution from the disk was under reaction control. The in situ monitoring of Mn dissolution from the spinel was carried out under various conditions. The ring currents exhibited maxima corresponding to the end-of-charge (EOC) and end-of-discharge (EOD), with the largest peak at EOC. The results suggest that the dissolution of Mn from spinel LiMn{sub 2}O{sub 4} occurs during charge/discharge cycling, especially in a charged state (at >4.1 V) and in a discharged state (at <3.1 V). The largest peak at EOC demonstrated that Mn dissolution took place mainly at the top of charge. At elevated temperatures, the ring cathodic currents were larger due to the increase of Mn dissolution rate.

Sustainable intensification through rotations with grain legumes in Sub-Saharan Africa

NARCIS (Netherlands)

Franke, A.C.; Brand, van den G.J.; Vanlauwe, B.; Giller, K.E.

2018-01-01

We conducted a systematic review of literature on the residual effects of grain legumes in cereal-based systems of sub-Saharan Africa (SSA) to quantify the magnitude and variability of rotational effects, to explore the importance of environmental and management factors in determining variability

Daily measure of the constancy of rotation in the evaluation of geometric and dosimetric parameters of the tomotherapy

International Nuclear Information System (INIS)

Erzilbengoa, M.; Moral, S.; Bragado, L.; Guisasola, M. A.

2011-01-01

The daily test performance called ''Rotating Constancia'', based on the methodology developed by Balog ''Helical tomotherapy dynamic quality assurance'' (2006), has allowed us over these 2 years to assess the response to TomoTherapy machine parameters given dose, travel speed table offset of the same, position of the green lasers, field size, rotation time and energy index of the beam parameters can be measured without intensity modulation.

Possible mechanism of the interplanetary medium effect on the diurnal rotation rate of the Earth

International Nuclear Information System (INIS)

Krymskij, P.F.

1993-01-01

Mechanism is proposed for effect of the solar wind and interplanetary magnetic field on the Earth rotation. In the mechanism base is Hall current generation in the plasma layer of the magnetosphere tail

Partial slip effect in flow of magnetite-Fe{sub 3}O{sub 4} nanoparticles between rotating stretchable disks

Energy Technology Data Exchange (ETDEWEB)

Hayat, Tasawar [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Qayyum, Sumaira [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Imtiaz, Maria, E-mail: mi_qau@yahoo.com [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Alzahrani, Faris; Alsaedi, Ahmed [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2016-09-01

This paper addresses the flow of magnetic nanofluid (ferrofluid) between two parallel rotating stretchable disks with different rotating and stretching velocities. Water based fluid comprising magnetite-Fe{sub 3}O{sub 4} nanoparticles is addressed. Velocity slip and temperature jump at solid–fluid interface are also taken into account. Appropriate transformations reduce the nonlinear partial differential system to ordinary differential system. Convergent series solutions are obtained. Effects of various pertinent parameters on the velocity and temperature profiles are shown and evaluated. Computations for skin friction coefficient and Nusselt number are presented and examined for the influence of involved parameters. It is noted that tangential velocity of fluid decreases for larger velocity slip parameter. Fluid temperature also reduces for increasing value of thermal slip parameter. Surface drag force and heat transfer rate at lower disk are enhanced when magnetic field strength is increased. - Highlights: • Flow and heat transfer of ferrofluid induced by two stretchable rotating disks with velocity and thermal slips are explored. • Fluid temperature increases for larger solid volume fraction of nanofluid. • Heat transfer rate decreases for increasing values of thermal slip parameter.

The zonal tidal effect on the variation in the rotation rate of the Earth with a fluid core I. Improvements on the theoretical formulae

Science.gov (United States)

Zhang, Han-Wei; Zheng, Yong; Du, Lan; Pan, Guan-Song

The tidal variation in Earth's rotation rate is a periodical response to solar-lunar tide generating potential (TGP). In this article, the factor of the fluid core, which is related with the variation in the polar moment of inertia of the Earth, is considered and introduced distinctly into the theoretical formula of the variation in the Earth's rotational rate caused by lunar-solar tide-producing force based on the dynamics principle of the fluid core Earth. Different from previously work, some Doodson developments are given including the variation formulae of the Earth's rotational rate, LOD and UT1. The reasons are pointed why the moment of inertia for the scale should be the effective polar rotational moment of inertia of the mantle and the Love number should be the effective Love number of the mantle. It is also indicated that the factor of the fluid core is consistent with the effect of the effective Love number of the mantle due to fluid core.

The oxygen-isotope effect on the in-plane penetration depth in underdoped Y{sub 1-x} Pr{sub x} Ba{sub 2} Cu{sub 3} O{sub 7-{delta}} as revealed by muon-spin rotation

Energy Technology Data Exchange (ETDEWEB)

Khasanov, R [Physik-Institut der Universitaet Zuerich, CH-8057 Zurich (Switzerland); Shengelaya, A [Physik-Institut der Universitaet Zuerich, CH-8057 Zurich (Switzerland); Conder, K [Laboratory for Neutron Scattering, ETH Zuerich and PSI Villigen, CH-5232 Villigen PSI (Switzerland); Morenzoni, E [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Savic, I M [Faculty of Physics, University of Belgrade, 11001 Belgrade (Yugoslavia); Keller, H [Physik-Institut der Universitaet Zuerich, CH-8057 Zurich (Switzerland)

2003-01-22

The oxygen-isotope ({sup 16}O/{sup 18}O) effect (OIE) on the in-plane penetration depth {lambda}{sub ab} (0) in underdoped Y{sub 1-x} Pr{sub x} Ba{sub 2} Cu{sub 3} O{sub 7-{delta}} was studied by means of muon-spin rotation. A pronounced OIE on {lambda}{sub ab}{sup -2} (0) was observed with a relative isotope shift of {delta}{lambda}{sub ab}{sup -2} /{lambda} {sub ab}{sup -2} = -5(2)% for x=0.3 and -9(2)% for x=0.4. The OIE exponents of T{sub c} and of {lambda}{sub ab}{sup -2} (0) exhibit a relation that appears to be generic for cuprate superconductors. (letter to the editor)

Synthesis and crystal structure of the rare earth borogermanate EuGeBO{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Chi, Yang; Zhuang, Yan; Guo, Sheng-Ping [Yangzhou Univ., Jiangsu (China). College of Chemistry and Chemical Engineering

2017-03-01

The synthesis and crystal structure of the rare earth borogermanate EuGeBO{sub 5} are reported. It is synthesized by high-temperature solid-state reaction and crystallizes in the monoclinic space group P2{sub 1}/c (no. 14) with the unit cell parameters a=4.8860(5), b=7.5229(8), c=9.9587(10) Aa, and β=91.709(3) . Its crystal structure features a polyanion-type layer (GeBO{sub 5}){sup 3-} constructed by BO{sub 4} and GeO{sub 4} tetrahedra connected alternatingly. Eu{sup 3+} ions are located in cavities and are coordinated by eight O atoms. Various structures of the related compounds REMM'O{sub 5} (RE=rare earth metal; M=Si, Ge, and Sn; M'=B, Al, and Ga) are also discussed.

Rotational states of odd Z rare earth proton emitter 131Eu

International Nuclear Information System (INIS)

Aggarwal, Mamta

2013-01-01

Recent observation of proton radioactivity and rotational bands in 131 Eu and 141 Ho with large deformations β ≈ 0.3 and γ softness have already proven the study of excited states of deformed proton emitters a source of valuable information on the structure of proton decaying states and response of proton emitters on the stress of rotation. The rare earth nuclei below the N = 82 shell closure form one of the few regions of the nuclear chart where nuclear shapes are expected to change rapidly with coexistence of oblate and prolate shapes in some nuclei. We evaluate shapes and deformation of 131 Eu by combining classical collective properties of the liquid drop model with the quantum corrections due to shell effects via Strutinsky formalism adequately described in. Excited states are treated using statistical theory. Nuclear shapes and deformation are traced by minimizing free energy (F = E-TS) w.r.t. deformation parameters β from 0 to 0.4 in steps of 0.01 and γ from -180° (oblate with symmetry axis parallel to the rotation axis) to -120° (prolate with symmetry axis perpendicular to rotation axis) and then to -60° (oblate collective) to 0° (prolate non-collective)

Magnetic properties and structural transitions of fluorite-related rare earth osmates Ln{sub 3}OsO{sub 7} (Ln=Pr, Tb)

Energy Technology Data Exchange (ETDEWEB)

Hinatsu, Yukio, E-mail: hinatsu@sci.hokudai.ac.jp [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Doi, Yoshihiro [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan)

2013-02-15

Ternary rare-earth osmates Ln{sub 3}OsO{sub 7} (Ln=Pr, Tb) have been prepared. They crystallize in an ortho-rhombic superstructure of cubic fluorite with space group Cmcm. Both of these compounds undergo a structural phase transition at 130 K (Ln=Pr) and 580 K (Ln=Tb). These compounds show complex magnetic behavior at low temperatures. Pr{sub 3}OsO{sub 7} exhibits magnetic transitions at 8 and 73 K, and Tb{sub 3}OsO{sub 7} magnetically orders at 8 and 60 K. The Os moments become one-dimensionally ordered, and when the temperature is furthermore decreased, it provokes the ordering in the Ln{sup 3+} sublattice that simultaneously becomes three-dimensionally ordered with the Os sublattice. - Graphical abstract: Ternary rare-earth osmates Ln{sub 3}OsO{sub 7} (Ln=Pr, Tb) have been prepared. They crystallize in an orthorhombic superstructure of cubic fluorite with space group Cmcm. Both of these compounds undergo a structural phase transition at 130 K (Ln=Pr) and 580 K (Ln=Tb). These compounds show complex magnetic behavior at low temperatures. Pr{sub 3}OsO{sub 7} exhibits magnetic transitions at 8 and 73 K, and Tb{sub 3}OsO{sub 7} magnetically orders at 8 and 60 K. Highlights: Black-Right-Pointing-Pointer Ternary rare-earth osmates Ln{sub 3}OsO{sub 7} (Ln=Pr, Tb) with an ordered defect-fluorite structure have been prepared. Black-Right-Pointing-Pointer Both of these compounds undergo a structural phase transition at 130 K (Ln=Pr) and 580 K (Ln=Tb). Black-Right-Pointing-Pointer These compounds show complex magnetic behavior at low temperatures due to magnetic ordering of Ln and Os.

Determining the Ocean's Role on the Variable Gravity Field and Earth Rotation

Science.gov (United States)

Ponte, Rui M.; Frey, H. (Technical Monitor)

2000-01-01

A number of ocean models of different complexity have been used to study changes in the oceanic angular momentum (OAM) and mass fields and their relation to the variable Earth rotation and gravity field. Time scales examined range from seasonal to a few days. Results point to the importance of oceanic signals in driving polar motion, in particular the Chandler and annual wobbles. Results also show that oceanic signals have a measurable impact on length-of-day variations. Various circulation features and associated mass signals, including the North Pacific subtropical gyre, the equatorial currents, and the Antarctic Circumpolar Current play a significant role in oceanic angular momentum variability. The impact on OAM values of an optimization procedure that uses available data to constrain ocean model results was also tested for the first time. The optimization procedure yielded substantial changes, in OAM, related to adjustments in both motion and mass fields,as well as in the wind stress torques acting on the ocean. Constrained OAM values were found to yield noticeable improvements in the agreement with the observed Earth rotation parameters, particularly at the seasonal timescale.

Enhanced NH{sub 3} gas sensing performance based on electrospun alkaline-earth metals composited SnO{sub 2} nanofibers

Energy Technology Data Exchange (ETDEWEB)

Xu, Shuang [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Key Laboratory of Physical Chemistry, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); Kan, Kan [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Key Laboratory of Physical Chemistry, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); Daqing Branch, Heilongjiang Academy of Sciences, Daqing 163319 (China); Yang, Ying; Jiang, Chao [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Key Laboratory of Physical Chemistry, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); Gao, Jun [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Key Laboratory of Physical Chemistry, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); Department of Chemistry, Harbin Normal University, Harbin 150025 (China); Jing, Liqiang [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Key Laboratory of Physical Chemistry, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); Shen, Peikang [Department of Physics and Engineering Sun Yat-sen University, Guangzhou 510275 (China); Li, Li, E-mail: llwjjhlju@sina.cn [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Key Laboratory of Physical Chemistry, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, School of Chemistry and Material Science, Heilongjiang University, Harbin 150080 (China); and others

2015-01-05

Highlights: • The small-sized SnO{sub 2} (5–7 nm) were obtained by adding the alkaline-earth. • Sr-composited SnO{sub 2} nanofibers showed uniform nanotubes structure (Sr/SnO{sub 2}). • Sr/SnO{sub 2} showed an excellent sensing performance to NH{sub 3} at room temperature. - Abstract: One-dimensional alkaline-earth metals composited SnO{sub 2} (Ae/SnO{sub 2}) nanofibres were fabricated via electrospinning technique, followed by thermal treatment at 600 °C for 5 h. Transmission electron microscopy (TEM) studies showed that the nanoparticles size of Ae/SnO{sub 2} was 5–7 nm, which was smaller than the pristine SnO{sub 2} nanorods attached by 20 nm nanoparticles. Moreover, Sr/SnO{sub 2} nanocomposites showed uniform nanotubes structure with the wall thickness of about 30 nm, in which all the nanoparticles were connected to their neighbors by necks. The Sr/SnO{sub 2} nanotubes exhibited an excellent sensing response toward NH{sub 3} gas at room temperature, lower detection limit (10 ppm), faster response time (6 s towards 2000 ppm∼16 s towards 10 ppm) and better reversibility compared to the pristine SnO{sub 2} nanorods. The enhanced sensor performances were attributed to the higher conductivity of the Sr/SnO{sub 2}. Mott–Schottky plots (M–S) and electrochemical impedance spectroscopy (EIS) measurements indicated that the carrier density of Sr/SnO{sub 2} nanotubes was 3 fold of that pristine SnO{sub 2}.

The Nature of the Distinctive Microscopic Features in R<sub>5sub>(Si_xGe>1-xsub>)>4sub> Magnetic Refrigeration Materials

Energy Technology Data Exchange (ETDEWEB)

Ugurlu, Ozan [Iowa State Univ., Ames, IA (United States)

2006-01-01

Magnetic refrigeration is a promising technology that offers a potential for high energy efficiency. The giant magnetocaloric effect of the R<sub>5sub>(Si<sub>x>, Ge<sub>1-xsub>)>4sub> alloys (where R=rare-earth and O ≤ x ≤ 1), which was discovered in 1997, make them perfect candidates for magnetic refrigeration applications. In this study the microstructures of Gd<sub>5sub>(Six>, Ge<sub>1-xsub>)>4sub> alloys have been characterized using electron microscopy techniques, with the focus being on distinctive linear features first examined in 1999. These linear features have been observed in R<sub>5sub>(Six>, Ge<sub>1-xsub>)>4sub> alloys prepared from different rare-earths (Gd, Tb, Dy and Er) with different crystal structures (Gd<sub>5sub>Si>4sub>-type orthorhombic, monoclinic and Gd<sub>5sub>Ge>4sub>-type orthorhombic). Systematic scanning electron microscope studies revealed that these linear features are actually thin-plates, which grow along specific directions in the matrix material. The crystal structure of the thin-plates has been determined as hexagonal with lattice parameters a=b=8.53 Å and c=6.40 Å using selected area diffraction (SAD). Energy dispersive spectroscopy analysis, carried out in both scanning and transmission electron microscopes, showed that the features have a composition approximating to R<sub>5sub>Six,Ge>1-xsub>)>3sub>.phase. Orientation relationship between the matrix and the thin-plates has been calculated as [- 1010](1-211)<sub>p>//[010](10-2)<sub>m>. The growth direction of the thin plates are calculated as (22 0 19) and (-22 0 19) by applying the Ag approach of Zhang and Purdy to the SAD patterns of this system. High Resolution TEM images of the Gd_{5sub>Ge>4sub> were used to study the crystallographic relationship. A terrace-ledge structure was observed at the interface and a 7° rotation of the reciprocal lattices}

Taking into account the Earth's rotation in experiments on search for the electric dipole moment of neutron

International Nuclear Information System (INIS)

Silenko, A.Ya.

2007-01-01

Analysis of the problem of taking into account the Earth's rotation in a search for the electric dipole moment (EDM) of the neutron in experiments with ultracold neutrons and in a diffractional experiment is fulfilled. Taking into account the Earth's rotation in the diffractional experiment gives an exactly calculated correction which is negligible as compared with the accuracy reached at present time. In the experiments with ultracold neutrons, the correction is greater than the systematical error and the exact calculation of it needs further investigation. In this connection, further developments of diffractional method would considerably promote progress in the search for the electric dipole moment of the neutron

Synthesis, characterization, and chemical bonding analysis of the lithium alkaline-earth metal gallide nitrides Li{sub 2}(Ca{sub 3}N){sub 2}[Ga{sub 4}] and Li{sub 2}(Sr{sub 3}N){sub 2}[Ga{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Pathak, Manisha; Bobnar, Matej; Ormeci, Alim; Hoehn, Peter [Chemische Metallkunde, Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Stoiber, Dominik; Niewa, Rainer [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Ovchinnikov, Alexander [Chemische Metallkunde, Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Department of Chemistry and Biochemistry, University of Delaware, Newark, DE (United States)

2017-11-17

Large single crystals of Li{sub 2}(Ca{sub 3}N){sub 2}[Ga{sub 4}] and Li{sub 2}(Sr{sub 3}N){sub 2}[Ga{sub 4}] up to several mm in size were grown from mixtures of the respective elements and binary alkaline-earth metal nitrides in reactive lithium melts employing a modified high-temperature centrifugation-aided filtration (HTCAF) technique. The main structural features of these isotypic phases are stella quadrangula building units [Ga{sub 4}]Li{sub 4/2} and octahedra (Nae{sub 6/2}), which form two independent interpenetrating networks. The phases crystallize in the η-carbide structure and represent diamagnetic small bandgap semiconductors. Real-space chemical bonding analysis indicates predominantly ionic bonding. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Dynamics of the accumulation process of the Earth group of planets: Formation of the reverse rotation of Venus

Science.gov (United States)

Koslov, N. N.; Eneyev, T. M.

1979-01-01

A numerical simulation of the process of formation of the terrestrial planets is carried within the framework of a new theory for the accumulation of planetary and satellite systems. The numerical simulation permitted determining the parameters of the protoplanetary disk from which Mercury, Venus and the Earth were formed as result of the evolution. The acquisition of a slow retrograde rotation for Venus was discovered during the course of the investigation, whereas Mercury and the Earth acquired direct rotation about their axes. Deviations of the semimajor axes of these three planets as well as the masses of the Earth and Venus from the true values are small as a rule (l 10%). It is shown that during the accumulation of the terrestrial planets, there existed a profound relationship between the process of formation of the orbits and masses of the planet and the process of formation of their rotation about their axes. Estimates are presented for the radii of the initial effective bodies and the time of evolution for the terrestrial accumulation zone.

IMPROVED DETERMINATION OF THE 1{sub 0}-0{sub 0} ROTATIONAL FREQUENCY OF NH{sub 3}D{sup +} FROM THE HIGH-RESOLUTION SPECTRUM OF THE {nu}{sub 4} INFRARED BAND

Energy Technology Data Exchange (ETDEWEB)

Domenech, J. L.; Cueto, M.; Herrero, V. J.; Tanarro, I. [Molecular Physics Department, Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, E-28006 Madrid (Spain); Tercero, B.; Cernicharo, J. [Department of Astrophysics, CAB, INTA-CSIC, Crta Torrejon-Ajalvir Km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Fuente, A., E-mail: jl.domenech@csic.es [Observatorio Astronomico Nacional, Apdo. 112, E-28803 Alcala de Henares (Spain)

2013-07-01

The high-resolution spectrum of the {nu}{sub 4} band of NH{sub 3}D{sup +} has been measured by difference frequency IR laser spectroscopy in a multipass hollow cathode discharge cell. From the set of molecular constants obtained from the analysis of the spectrum, a value of 262817 {+-} 6 MHz ({+-}3{sigma}) has been derived for the frequency of the 1{sub 0}-0{sub 0} rotational transition. This value supports the assignment to NH{sub 3}D{sup +} of lines at 262816.7 MHz recorded in radio astronomy observations in Orion-IRc2 and the cold prestellar core B1-bS.

Rotationally resolved pulsed-field ionization photoelectron bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) in the energy range of 17.0-18.2 eV

Energy Technology Data Exchange (ETDEWEB)

Song, Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Evans, M. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Ng, C. Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Hsu, C.-W. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jarvis, G. K. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2000-01-15

We have obtained rotationally resolved pulsed-field ionization photoelectron (PFI-PE) spectra for O{sub 2} in the energy range of 17.05-18.13 eV, covering the ionization transitions O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12,N{sup +})(<-)O{sub 2}(X {sup 3}{sigma}{sub g}{sup -},v{sup ''}=0,N{sup ''}). Although these O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}) PFI-PE bands have significant overlaps with vibrational bands for O{sub 2}{sup +}(a {sup 4}{pi}{sub u}) and O{sub 2}{sup +}(X {sup 2}{pi}{sub g}), we have identified all the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) bands by simulation of spectra obtained using supersonically cooled O{sub 2} samples with rotational temperatures {approx_equal}20 and 220 K. While these v{sup +}=0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O{sub 2}{sup +}(A {sup 2}{pi}{sub u}), the PFI-PE bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) states are strongly perturbed by a nearby electronic state. (c) 2000 American Institute of Physics.

Experimental and theoretical study of rotationally inelastic diffraction of H{sub 2}(D{sub 2}) from methyl-terminated Si(111)

Energy Technology Data Exchange (ETDEWEB)

Nihill, Kevin J.; Hund, Zachary M.; Sibener, S. J., E-mail: s-sibener@uchicago.edu [The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States); Muzas, Alberto; Cueto, Marcos del [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Díaz, Cristina [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain); Frankcombe, Terry [School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra ACT 2610 (Australia); Plymale, Noah T.; Lewis, Nathan S. [Division of Chemistry and Chemical Engineering, Beckman Institute and Kavli Nanoscience Institute, California Institute of Technology, 210 Noyes Laboratory, 127-72, Pasadena, California 91125 (United States); Martín, Fernando [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain); Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid (Spain)

2016-08-28

Fundamental details concerning the interaction between H{sub 2} and CH{sub 3}–Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H{sub 2} and D{sub 2} from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H{sub 2} compared to the strong RID features observed for D{sub 2} over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH{sub 3}–Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H{sub 2} and D{sub 2} have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H{sub 2} (D{sub 2}) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H{sub 2}(D{sub 2})/CH{sub 3}−Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H{sub 2} with a hybrid organic-semiconductor interface, which can be used

THE MISSION ACCESSIBLE NEAR-EARTH OBJECTS SURVEY (MANOS): FIRST PHOTOMETRIC RESULTS

Energy Technology Data Exchange (ETDEWEB)

Thirouin, A.; Moskovitz, N.; Burt, B. [Lowell Observatory, 1400 W Mars Hill Rd, Flagstaff, AZ 86001 (United States); Binzel, R. P.; DeMeo, F. E.; Person, M. J. [Massachusetts Institute of Technology (MIT), 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Christensen, E. [University of Arizona, Tucson, AZ (United States); Polishook, D. [Department of Earth and Planetary Science, Weizmann Institute, Herzl St 234, Rehovot, 7610001 (Israel); Thomas, C. A. [Planetary Science Institute (PSI), 1700 E Fort Lowell Road 106, Tucson, AZ 85719 (United States); Trilling, D.; Hinkle, M.; Avner, D. [Department of Physics and Astronomy, P.O. Box 6010, Northern Arizona University, Flagstaff AZ 86001 (United States); Willman, M. [University of Hawaii, Pukalani, HI 96788 (United States); Aceituno, F. J., E-mail: thirouin@lowell.edu [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, S/N, Granada, E-18008 (Spain)

2016-12-01

The Mission Accessible Near-Earth Objects Survey aims to physically characterize sub-km near-Earth objects (NEOs). We report the first photometric results from the survey that began in 2013 August. Photometric observations were performed using 1–4 m class telescopes around the world. We present rotational periods and light curve amplitudes for 86 sub-km NEOs, though in some cases only lower limits are provided. Our main goal is to obtain light curves for small NEOs (typically, sub-km objects) and estimate their rotational periods, light curve amplitudes, and shapes. These properties are used for a statistical study to constrain overall properties of the NEO population. A weak correlation seems to indicate that smaller objects are more spherical than larger ones. We also report seven NEOs that are fully characterized (light curve and visible spectra) as the most suitable candidates for a future human or robotic mission. Viable mission targets are objects fully characterized, with Δ v {sup NHATS} ≤ 12 km s{sup −1}, and a rotational period P  > 1 hr. Assuming a similar rate of object characterization as reported in this paper, approximately 1230 NEOs need to be characterized in order to find 100 viable mission targets.

THE MISSION ACCESSIBLE NEAR-EARTH OBJECTS SURVEY (MANOS): FIRST PHOTOMETRIC RESULTS

International Nuclear Information System (INIS)

Thirouin, A.; Moskovitz, N.; Burt, B.; Binzel, R. P.; DeMeo, F. E.; Person, M. J.; Christensen, E.; Polishook, D.; Thomas, C. A.; Trilling, D.; Hinkle, M.; Avner, D.; Willman, M.; Aceituno, F. J.

2016-01-01

The Mission Accessible Near-Earth Objects Survey aims to physically characterize sub-km near-Earth objects (NEOs). We report the first photometric results from the survey that began in 2013 August. Photometric observations were performed using 1–4 m class telescopes around the world. We present rotational periods and light curve amplitudes for 86 sub-km NEOs, though in some cases only lower limits are provided. Our main goal is to obtain light curves for small NEOs (typically, sub-km objects) and estimate their rotational periods, light curve amplitudes, and shapes. These properties are used for a statistical study to constrain overall properties of the NEO population. A weak correlation seems to indicate that smaller objects are more spherical than larger ones. We also report seven NEOs that are fully characterized (light curve and visible spectra) as the most suitable candidates for a future human or robotic mission. Viable mission targets are objects fully characterized, with Δ v NHATS  ≤ 12 km s −1 , and a rotational period P  > 1 hr. Assuming a similar rate of object characterization as reported in this paper, approximately 1230 NEOs need to be characterized in order to find 100 viable mission targets.

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

Science.gov (United States)

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.

Assimilation of Earth rotation parameters into a global ocean model (FESOM)

Science.gov (United States)

Androsov, A.; Schröter, J.; Brunnabend, S.; Saynisch, J.

2012-04-01

Earth Rotation Parameters (ERP) are used to improve estimates of the ocean circulation and mass budget. GRACE data can be used for verification or for further improvements. The Finite Element Sea-ice Ocean Model (FESOM) is used to simulate weekly ocean circulation and mass variations. The FESOM model is a hydrostatic ocean circulation model with a fully non-linear free surface. It solves the hydrostatic primitive equations with volume (Boussinesq approximation) and mass (Greatbatch correction) conservation. Fresh water exchange with the atmosphere and land is modelled as mass flux. This flux is the weakest part of the mass budget as it is the difference of large and uncertain quantities: evaporation, precipitation and river runoff. All uncertainties included in these parameters are directly reflected in the model results. ERP help in closing the budget in a realistic manner. Our strategy is designed for testing parametric estimation on a weekly basis. First, Oceanographic Earth rotation parameters (OERP) are calculated by subtracting atmospheric and hydrologic estimates from observed ERP. They are compared to OERP derived from a global ocean circulation model. The difference can be inverted to diagnose a correction of the oceanic mass budget. Additionally mass variations measured by GRACE are used for verification. In a second step, the global mass correction parameter, derived by the inversion, is used to improve the fresh water budget of FESOM.

Thermospheric neutral temperatures derived from charge-exchange produced N{sub 2}{sup +} Meinel (1,0) rotational distributions

Energy Technology Data Exchange (ETDEWEB)

Mutiso, C.K.; Zettergren, M.D.; Hughes, J.M.; Sivjee, G.G. [Embry-Riddle Aeronautical Univ., Daytona Beach, FL (United States). Space Physics Research Lab.

2013-06-01

Thermalized rotational distributions of neutral and ionized N{sub 2} and O{sub 2} have long been used to determine neutral temperatures (T{sub n}) during auroral conditions. In both bright E-region (sub n} in the E-region cannot likewise be used to obtain T{sub n} in the F-region. Nevertheless, charge-exchange reactions between high-altitude (>or similar 130 km) species provide an exception to this situation. In particular, the charge-exchange reaction O{sup +}({sup 2}D)+N{sub 2}(X) {yields}N{sub 2}{sup +} (A{sup 2}{Pi}{sub u}, {nu}' = 1) + O({sup 3}P) yields thermalized N{sub 2}{sup +} Meinel (1,0) emissions, which, albeit weak, can be used to derive neutral temperatures at altitudes of {proportional_to} 130 km and higher. In this work, we present N{sub 2}{sup +} Meinel (1,0) rotational temperatures and brightnesses obtained at Svalbard, Norway, during various auroral conditions. We calculate T{sub n} at thermospheric altitudes of 130-180 km from thermalized rotational populations of N{sub 2}{sup +} Meinel (1,0); these emissions are excited by soft electron (sub n} from chargeexchange excited N{sub 2}{sup +} Meinel (1,0) emissions provides an additional means of remotely sensing the neutral atmosphere, although certain limiting conditions are necessary. These include precipitation of low-energy electrons, and a non-sunlit emitting layer. (orig.)

Rotational malalignment after closed intramedullary nailing of femoral shaft fractures and its influence on daily life.

Science.gov (United States)

Karaman, Ozgur; Ayhan, Egemen; Kesmezacar, Hayrettin; Seker, Ali; Unlu, Mehmet Can; Aydingoz, Onder

2014-10-01

Any intraoperative rotational malalignment during intramedullary nailing (IMN) of femoral shaft fractures will become permanent. We hypothesized that rotational malalignment of the femur and its compensatory biomechanics may induce problems in the hip, knee, patellofemoral and ankle joints. We purposed to clarify the influence of a femoral rotational malalignment of ≥10° on daily activities. Twenty-four femoral shaft fracture patients treated with closed antegrade IMN were included. At last follow-up, to reveal any rotational malalignment, computerized tomography (CT) scans of both femurs (injured and uninjured sides) were examined. The patient groups with or without CT-detected true rotational malalignment ≥10° were compared with respect to the activity scores. Ten of the 24 patients (41.7%) had a CT-detected true rotational malalignment of ≥10° compared with the unaffected side. The AOFAS scores were 100.00 for all of the patients. LKS, WOMAC knee, and WOMAC hip scores were significantly decreased in the patients with rotational malalignment compared to those without. Patients without rotational malalignment tolerated climbing stairs significantly better than those with rotational malalignment. Patients who could not tolerate climbing stairs were consistently complaining of anterior knee pain. A femoral rotational malalignment of ≥10° is symptomatic for the patients, and the hip, knee, and patellofemoral joints were affected. Because of the possibly altered joint loadings and biomechanics, these could render patients prone to degenerative joint disease. In addition, due to the high rates of rotational malalignment after femoral shaft fracture and consequent malpractice claims, it is important for surgeons to be more aware of rotational alignment during surgery.

A Study on Electrochemical Reduction of Rare Earth Oxides in Molten LiCl-Li{sub 2}O Salt

Energy Technology Data Exchange (ETDEWEB)

Lee, Min Woo; Jeong, Sang Mun; Lee, See Hoon [Chungbook National University, Chungju (Korea, Republic of); Sohn, Jung Min [Chonbuk National University, Jeonju (Korea, Republic of)

2016-05-15

In this study, the electrochemical reduction of RE{sub 2}O{sub 3} (RE = Nd or Ce) has been conducted via co-reduction NiO to increase the reduction degree of the rare earth oxides in molten molten LiCl containing 1wt% Li{sub 2}O. The electrochemical reduction behavior of the mixed RE{sub 2}O{sub 3}-NiO oxide has been investigated and the reduction path of RE{sub 2}O{sub 3} has been proposed. An electorchemical spent fuel processing technology, pyroprocessing, has been developed for recycling of spent fuel to be applied to a sodium-cooled fast reactor. The spent fuel is reduced in the oxide reduction process. It is well known that the rare earth oxides are hardly reduced due to their electrochemical and thermodynamic stability. The rare earth oxides unreduced in the reduction process can cause problems via reaction with UCl{sub 3} in the electrorefiner. To tackle those problems, the electrochemical reduction of rare earth oxide has been conducted via co-reduction of NiO in LiCl molten salt containing 1 wt% Li{sub 2}O. The reduction of the oxide mixture starts from the reduction of NiO to Ni, followed by that of RE{sub 2}O{sub 3} on the produced Ni to form intermetallic RENi{sub 5}. The mixed oxide pellets were successfully reduced to the RENi5 alloy by constant electrolysis at 3.0 V at 650 .deg. C. The crucial aspect to these results is that the thermodynamically stable rare-earth oxide, Nd{sub 2}O{sub 3} was successfully converted to the metal in the presence of NiO.

Adiabatic decay of internal solitons due to Earth's rotation within the framework of the Gardner-Ostrovsky equation

Science.gov (United States)

Obregon, Maria; Raj, Nawin; Stepanyants, Yury

2018-03-01

The adiabatic decay of different types of internal wave solitons caused by the Earth's rotation is studied within the framework of the Gardner-Ostrovsky equation. The governing equation describing such processes includes quadratic and cubic nonlinear terms, as well as the Boussinesq and Coriolis dispersions: (ut + c ux + α u ux + α1 u2 ux + β uxxx)x = γ u. It is shown that at the early stage of evolution solitons gradually decay under the influence of weak Earth's rotation described by the parameter γ. The characteristic decay time is derived for different types of solitons for positive and negative coefficients of cubic nonlinearity α1 (both signs of that parameter may occur in the oceans). The coefficient of quadratic nonlinearity α determines only a polarity of solitary wave when α1 0. It is found that the adiabatic theory describes well the decay of solitons having bell-shaped profiles. In contrast to that, large amplitude table-top solitons, which can exist when α1 is negative, are structurally unstable. Under the influence of Earth's rotation, they transfer first to the bell-shaped solitons, which decay then adiabatically. Estimates of the characteristic decay time of internal solitons are presented for the real oceanographic conditions.

Structural flexibility in magnetocaloric RE<sub>5sub>T>4sub> (RE=rare-earth; T=Si,Ge,Ga) materials: Effect of chemical substitution on structure, bonding and properties

Energy Technology Data Exchange (ETDEWEB)

Misra, Sumohan [Iowa State Univ., Ames, IA (United States)

2008-01-01

The binary, ternary and multicomponent intermetallic compounds of rare-earth metals (RE) with group 14 elements (Tt) at the RE<sub>5sub>Tt>4sub> stoichiometry have been known for over 30 years, but only in the past decade have these materials become a gold mine for solid-state chemistry, materials science and condensed matter physics. It all started with the discovery of a giant magnetocaloric effect in Gd<sub>5sub>Si>2sub>Ge>2sub>, along with other extraordinary magnetic properties, such as a colossal magnetostriction and giant magnetoresistance. The distinctiveness of this series is in the remarkable flexibility of the chemical bonding between well-defined, subnanometer-thick slabs and the resultant magnetic, transport, and thermodynamic properties of these materials. This can be controlled by varying either or both RE and Tt elements, including mixed rare-earth elements on the RE sites and different group 14 (or T = group 13 or 15) elements occupying the Tt sites. In addition to chemical means, the interslab interactions are also tunable by temperature, pressure, and magnetic field. Thus, this system provides a splendid 'playground' to investigate the interrelationships among composition, structure, physical properties, and chemical bonding. The work presented in this dissertation involving RE<sub>5sub>T>4sub> materials has resulted in the successful synthesis, characterization, property measurements, and theoretical analyses of various new intermetallic compounds. The results provide significant insight into the fundamental magnetic and structural behavior of these materials and help us better understand the complex link between a compound's composition, its observed structure, and its properties.

Daily monitoring of the land surface of the Earth

Science.gov (United States)

Mascaro, J.

2016-12-01

Planet is an integrated aerospace and data analytics company that operates the largest fleet of Earth-imaging satellites. With more than 140 cube-sats successfully launched to date, Planet is now collecting approximately 10 million square kilometers of imagery per day (3-5m per pixel, in red, green, blue and near infrared spectral bands). By early 2017, Planet's constellation will image the entire land surface of the Earth on a daily basis. Due to investments in cloud storage and computing, approximately 75% of imagery collected is available to Planet's partners within 24 hours of capture through an Application Program Interface. This unique dataset has enormous applications for monitoring the status of Earth's natural ecosystems, as well as human settlements and agricultural welfare. Through our Ambassadors Program, Planet has made data available for researchers in areas as disparate as human rights monitoring in refugee camps, to assessments of the impact of hydroelectric installations, to tracking illegal gold mining in Amazon forests, to assessing the status of the cryosphere. Here, we share early results from Planet's research partner network, including enhanced spatial and temporal resolution of NDVI data for agricultural health in Saudi Arabia, computation of rates of illegal deforestation in Southern Peru, estimates of tropical forest carbon stocks based on data integration with active sensors, and estimates of glacial flow rates. We synthesize the potentially enormous research and scientific value of Planet's persistent monitoring capability, and discuss methods by which the data will be disseminated into the scientific community.

Mass-radius relations and core-envelope decompositions of super-Earths and sub-Neptunes

International Nuclear Information System (INIS)

Howe, Alex R.; Burrows, Adam; Verne, Wesley

2014-01-01

Many exoplanets have been discovered with radii of 1-4 R ⊕ , between that of Earth and Neptune. A number of these are known to have densities consistent with solid compositions, while others are 'sub-Neptunes' likely to have significant H 2 -He envelopes. Future surveys will no doubt significantly expand these populations. In order to understand how the measured masses and radii of such planets can inform their structures and compositions, we construct models both for solid layered planets and for planets with solid cores and gaseous envelopes, exploring a range of core masses, H 2 -He envelope masses, and associated envelope entropies. For planets in the super-Earth/sub-Neptune regime for which both radius and mass are measured, we estimate how each is partitioned into a solid core and gaseous envelope, associating a specific core mass and envelope mass with a given exoplanet. We perform this decomposition for both ''Earth-like'' rock-iron cores and pure ice cores, and find that the necessary gaseous envelope masses for this important sub-class of exoplanets must range very widely from zero to many Earth masses, even for a given core mass. This result bears importantly on exoplanet formation and envelope evaporation processes.

A new trajectory concept for exploring the earth's geomagnetic tail

Science.gov (United States)

Farquhar, R. W.; Dunham, D. W.

1981-01-01

An innovative trajectory technique for a magnetotail mapping mission is described which can control the apsidal rotation of an elliptical earth orbit and keep its apogee segment inside the tail region. The required apsidal rotation rate of approximately 1 deg/day is achieved by using the moon to carry out a prescribed sequence of gravity-assist maneuvers. Apogee distances are alternately raised and lowered by the lunar-swingby maneuvers; several categories of the 'sun-synchronous' swingby trajectories are identified. The strength and flexibility of the new trajectory concept is demonstrated by using real-world simulations showing that a large variety of trajectory shapes can be used to explore the earth's geomagnetic tail between 60 and 250 R sub E.

Manifestations of the rotation and gravity of the Earth in high-energy physics experiments

Science.gov (United States)

Obukhov, Yuri N.; Silenko, Alexander J.; Teryaev, Oleg V.

2016-08-01

The inertial (due to rotation) and gravitational fields of the Earth affect the motion of an elementary particle and its spin dynamics. This influence is not negligible and should be taken into account in high-energy physics experiments. Earth's influence is manifest in perturbations in the particle motion, in an additional precession of the spin, and in a change of the constitutive tensor of the Maxwell electrodynamics. Bigger corrections are oscillatory, and their contributions average to zero. Other corrections due to the inhomogeneity of the inertial field are not oscillatory but they are very small and may be important only for the storage ring electric dipole moment experiments. Earth's gravity causes the Newton-like force, the reaction force provided by a focusing system, and additional torques acting on the spin. However, there are no observable indications of the electromagnetic effects due to Earth's gravity.

The influence of global warming in Earth rotation speed

Directory of Open Access Journals (Sweden)

R. Abarca del Rio

1999-06-01

Full Text Available The tendency of the atmospheric angular momentum (AAM is investigated using a 49-year set of monthly AAM data for the period January 1949-December 1997. This data set is constructed with zonal wind values from the reanalyses of NCEP/NCAR, used in conjunction with a variety of operationally produced AAM time series with different independent sources and lengths over 1976-1997. In all the analyzed AAM series the linear trend is found to be positive. Since the angular momentum of the atmosphere-earth system is conserved this corresponds to a net loss of angular momentum by the solid earth, therefore decreasing the Earth rotation speed and increasing the length of day (LOD. The AAM rise is significant to the budget of angular momentum of the global atmosphere-earth system; its value in milliseconds/century (ms/cy is +0.56 ms/cy, corresponding to one-third of the estimated increase in LOD (+1.7 ms/cy. The major contribution to this secular trend in AAM comes from the equatorial Tropopause. This is consistent with results from a previous study using a simplified aqua-planet model to investigate the AAM variations due to near equatorial warming conditions. During the same time interval, 1949-1997, the global marine + land-surface temperature increases by about 0.79 °C/cy, showing a linear correspondence between surface temperature increase and global AAM of about 0.07 ms per 0.1 °C. These results imply that atmospheric angular momentum may be used as an independent index of the global atmosphere's dynamical response to the greenhouse forcing, and as such, the length of day may be used as an indirect indicator of global warming.Key words. Meteorology and atmospheric dynamics (general circulation · Geodesy

The influence of global warming in Earth rotation speed

Directory of Open Access Journals (Sweden)

R. Abarca del Rio

Full Text Available The tendency of the atmospheric angular momentum (AAM is investigated using a 49-year set of monthly AAM data for the period January 1949-December 1997. This data set is constructed with zonal wind values from the reanalyses of NCEP/NCAR, used in conjunction with a variety of operationally produced AAM time series with different independent sources and lengths over 1976-1997. In all the analyzed AAM series the linear trend is found to be positive. Since the angular momentum of the atmosphere-earth system is conserved this corresponds to a net loss of angular momentum by the solid earth, therefore decreasing the Earth rotation speed and increasing the length of day (LOD. The AAM rise is significant to the budget of angular momentum of the global atmosphere-earth system; its value in milliseconds/century (ms/cy is +0.56 ms/cy, corresponding to one-third of the estimated increase in LOD (+1.7 ms/cy. The major contribution to this secular trend in AAM comes from the equatorial Tropopause. This is consistent with results from a previous study using a simplified aqua-planet model to investigate the AAM variations due to near equatorial warming conditions. During the same time interval, 1949-1997, the global marine + land-surface temperature increases by about 0.79 °C/cy, showing a linear correspondence between surface temperature increase and global AAM of about 0.07 ms per 0.1 °C. These results imply that atmospheric angular momentum may be used as an independent index of the global atmosphere's dynamical response to the greenhouse forcing, and as such, the length of day may be used as an indirect indicator of global warming.

Key words. Meteorology and atmospheric dynamics (general circulation · Geodesy

Substitution disorder and photoluminescent property of a new rare-earth borate: K{sub 3}TbB{sub 6}O{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Zhao, Dan; Ma, Fa-Xue; Huang, Min; Chen, Peng-Fei; Zhang, Rong-Hua [Henan Polytechnic Univ., Jiaozuo (China). College of Chemistry and Chemical Engineering; Zhang, Rui-Juan [Henan Polytechnic University, Jiaozuo (China). Academic Affairs Office; Wei, Wei [Capital Normal Univ., Beijing (China). Dept. of Chemistry

2016-11-01

A new rare-earth borate K{sub 3}TbB{sub 6}O{sub 12} has been prepared using the high temperature molten salt method and was structurally determined by single crystal X-ray diffraction analyses. The structure features a three-dimensional (3D) framework which is composed of isolated B{sub 5}O{sub 10}, KO{sub 6}, KO{sub 8} and TbO{sub 6} groups. An atom site in the 3{sub 2} screw axis is shared by K and Tb atoms with the molar ratio of 1:1. The self-activated photoluminescence (PL) property of K{sub 3}TbB{sub 6}O{sub 12} was studied. Under the excitation of 378 nm, the emission spectrum exhibits an intense green emission centered at 543-548 nm with the chromaticity coordinates (0.342, 0.590), which can be assigned to the {sup 5}D{sub 4} → {sup 7}F{sub 5} transition of Tb{sup 3+}. The excitation spectra cover a wide range from 330 to 385 nm, which suggests that the K{sub 3}TbB{sub 6}O{sub 12} phosphors can be effectively excited by a near-UV light source. One may expect that compound K{sub 3}TbB{sub 6}O{sub 12} can be used as a green phosphor pumped by near-UV LED chips.

A normal mode treatment of semi-diurnal body tides on an aspherical, rotating and anelastic Earth

Science.gov (United States)

Lau, Harriet C. P.; Yang, Hsin-Ying; Tromp, Jeroen; Mitrovica, Jerry X.; Latychev, Konstantin; Al-Attar, David

2015-08-01

Normal mode treatments of the Earth's body tide response were developed in the 1980s to account for the effects of Earth rotation, ellipticity, anelasticity and resonant excitation within the diurnal band. Recent space-geodetic measurements of the Earth's crustal displacement in response to luni-solar tidal forcings have revealed geographical variations that are indicative of aspherical deep mantle structure, thus providing a novel data set for constraining deep mantle elastic and density structure. In light of this, we make use of advances in seismic free oscillation literature to develop a new, generalized normal mode theory for the tidal response within the semi-diurnal and long-period tidal band. Our theory involves a perturbation method that permits an efficient calculation of the impact of aspherical structure on the tidal response. In addition, we introduce a normal mode treatment of anelasticity that is distinct from both earlier work in body tides and the approach adopted in free oscillation seismology. We present several simple numerical applications of the new theory. First, we compute the tidal response of a spherically symmetric, non-rotating, elastic and isotropic Earth model and demonstrate that our predictions match those based on standard Love number theory. Second, we compute perturbations to this response associated with mantle anelasticity and demonstrate that the usual set of seismic modes adopted for this purpose must be augmented by a family of relaxation modes to accurately capture the full effect of anelasticity on the body tide response. Finally, we explore aspherical effects including rotation and we benchmark results from several illustrative case studies of aspherical Earth structure against independent finite-volume numerical calculations of the semi-diurnal body tide response. These tests confirm the accuracy of the normal mode methodology to at least the level of numerical error in the finite-volume predictions. They also demonstrate

Eilenberger equation for rotating superfluid 3He and calculation of the upper critical angular velocity Ω/sub c/2

International Nuclear Information System (INIS)

Schopohl, N.

1980-01-01

On the basis of Gorkov's formulation of superconductivity theory, generalized Eilenberger equations are derived which apply to rotating superfluid 3 He in the presence of a magnetic field h and finite superflow v. In analyogy to conventional type II superconductors, the possibility of vortex solutions in discussed. An implicit equation determining the upper critical angular velocity Ω/sub c/2 as a function of temperature T, magnetic field h, and superflow v parallel to the rotation axis is-inferred from the linearized Eilenberger equations. In contrast to the case of slowly rotating 3 He-A, the solution of the eigenvalue problem determining the order parameter Δ near the the upper critical angular velocity admits no coreless vortex no coreless solutions. The space-dependent amplitude of the order parameter is analogous to Abrikosov's vortex array solution, while the spin-orbit part is given either by a polar-state type or an Anderson-Brinkman-Morel (ABM)-state-type eigensolution. Among the possible eigensolutions the polar-state type yields for vanishing superflow v the highest critical rotation frequency. For finite superflow v parallel to the rotation axis, however, the ABM-state-type solution is stabilized in comparison to the polar state for Vertical BarvVertical Bar> or approx. =0.2π(Tc/sub c/0/T/sub F/)v/sub f/ at zero temperature

Adsorption of Reactive Red 2 from aqueous solutions using Fe{sub 3}O{sub 4} nanoparticles prepared by co-precipitation in a rotating packed bed

Energy Technology Data Exchange (ETDEWEB)

Lin, Chia-Chang, E-mail: higee@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Lin, Yu-Shung [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Ho, Jui-Min [Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China)

2016-05-05

A rotating packed bed (RPB) that was operated at a rotating speed of 1800 rpm with liquid flow rates of 0.5 L/min was used to prepare Fe{sub 3}O{sub 4} nanoparticles (RPB-Fe{sub 3}O{sub 4}). The RPB-Fe{sub 3}O{sub 4} had a smaller average size and a narrower size distribution than the Fe{sub 3}O{sub 4} that was obtained from Aldrich, and so had a greater capacity to adsorb RR2. The effects of pH, Fe{sub 3}O{sub 4} dosage, initial RR2 concentration, and temperature on the adsorption of RR2 were examined experimentally using RPB-Fe{sub 3}O{sub 4}. A thermodynamic study revealed that the adsorption process was spontaneous and exothermic. The adsorption behavior was more consistent with the Langmuir model than with the Freundlich model, and the maximum adsorption capacity was 97.8 mg/g. At pH 3, 25 °C, an Fe{sub 3}O{sub 4} dosage of 0.30 g/L, and an initial RR2 concentration of 10 mg/L, RPB-Fe{sub 3}O{sub 4} effectively adsorbed RR2 with a removal efficiency of approximately 95% in 10 min. These promising results clearly reveal the potential of RPB-Fe{sub 3}O{sub 4} for use in the effective removal of dyes from aqueous solutions. - Highlights: • A novel magnetic adsorbent (Fe{sub 3}O{sub 4} nanoparticles) was prepared in RPB. • 95% removal of RR2 was achieved in 10 min using Fe{sub 3}O{sub 4} nanoparticles. • This investigation provides a novel treatment of dye-contaminated wastewater.

High Frequency Variations of Earth Rotation Parameters from GPS and GLONASS Observations

Directory of Open Access Journals (Sweden)

Erhu Wei

2015-01-01

Full Text Available The Earth’s rotation undergoes changes with the influence of geophysical factors, such as Earth’s surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS, Global Navigation Satellite System (GLONASS, and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas in Polar Motion (PM and 0.5 milli-seconds (ms in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM and hydrological angular momentum (HAM, which needs more detailed analysis with more geophysical data in the future.

Cluster model calculation for X-ray magnetic circular dichroism at rare-earth (R) L sub 2 sub , sub 3 absorption edges in R sub 2 Fe sub 1 sub 4 B

CERN Document Server

Asakura, K; Harada, I; Ogasawara, H; Fukui, K; Kotani, A

2002-01-01

X-ray magnetic circular dichroism (MCD) at the L sub 2 sub , sub 3 absorption edges for the entire series of rare-earth (RE) elements in R sub 2 Fe sub 1 sub 4 B (R=RE) is studied based on a cluster model including 10 RE and 16 Fe atoms. The cluster model takes into account band effects of RE 5d states, to which the electric dipole transition occurs from the core 2p states, as well as spin polarization of the 5d states due to the interatomic hybridization with the spin polarized Fe 3d states. We also take into account spin and orbital polarization of the 5d states due to the 5d-4f intra-atomic exchange interaction, and the 2p to 4f quadrupole transition. The calculated results are in satisfactory agreement with experimental ones, suggesting that the cluster model calculation provides a new method to calculate quantitatively MCD spectra of RE systems with complicated atomic arrangements. (author)

Calculations of the magnetic properties of R{sub 2}M{sub 14}B intermetallic compounds (R=rare earth, M=Fe, Co)

Energy Technology Data Exchange (ETDEWEB)

Ito, Masaaki, E-mail: masaaki.ito@neel.cnrs.fr [CNRS, Institut Néel, 25 rue des Martyrs, BP166, 38042 Grenoble (France); University Grenoble Alpes, Institut Néel, 38042 Grenoble (France); Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193 (Japan); Yano, Masao [Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193 (Japan); Dempsey, Nora M. [CNRS, Institut Néel, 25 rue des Martyrs, BP166, 38042 Grenoble (France); University Grenoble Alpes, Institut Néel, 38042 Grenoble (France); Givord, Dominique [CNRS, Institut Néel, 25 rue des Martyrs, BP166, 38042 Grenoble (France); University Grenoble Alpes, Institut Néel, 38042 Grenoble (France); Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil)

2016-02-15

The hard magnetic properties of “R–M–B” (R=rare earth, M=mainly Fe) magnets derive from the specific intrinsic magnetic properties encountered in Fe-rich R{sub 2}M{sub 14}B compounds. Exchange interactions are dominated by the 3d elements, Fe and Co, and may be modeled at the macroscopic scale with good accuracy. Based on classical formulae that relate the anisotropy coefficients to the crystalline electric field parameters and exchange interactions, a simple numerical approach is used to derive the temperature dependence of anisotropy in various R{sub 2}Fe{sub 14}B compounds (R=Pr, Nd, Dy). Remarkably, a unique set of crystal field parameters give fair agreement with the experimentally measured properties of all compounds. This implies reciprocally that the properties of compounds that incorporate a mixture of different rare-earth elements may be predicted accurately. This is of special interest for material optimization that often involves the partial replacement of Nd with another R element and also the substitution of Co for Fe. - Highlights: • Anisotropy constants derived from CEF parameters of R{sub 2}M{sub 14}B compounds (M=Fe, Co). • Anisotropy constants of all R{sub 2}Fe{sub 14}B compounds using unique set of CEF parameters. • Moment non-collinearity in magnetization processes under B{sub app} along hard axis.

Luminescence of rare-earth ions in Mg[sub 2]SiO[sub 4

Energy Technology Data Exchange (ETDEWEB)

Van der Voort, D; Maat-Gersdorf, I de; Blasse, G [Rijksuniversiteit Utrecht (Netherlands)

1992-01-01

The luminescence of the rare-earth ions Eu[sup 3+], Tb[sup 3+] and Ce[sup 3+] in Mg[sub 2]SiO[sub 4] is reported. The Tb[sup 3+] ion shows a change in emission colour from blue to green depending on the charge compensator. This is ascribed to a difference in coupling of the Tb[sup 3+] ion to the vibrational lattice modes. The Eu[sup 3+] ion has an average quantum efficiency under charge-transfer excitation of 60% at 4.2 and 20% at 300 K. The Ce[sup 3+] emission is situated in the blue and shows a Stokes shift of 3 500 cm[sup -1]. The relaxation of these ions in the excited state is discussed in terms of their positive effective charge and the stiffness of their surroundings.

Application of ring lasers to determine the directions to the poles of Earth's rotation

International Nuclear Information System (INIS)

Golyaev, Yu D; Kolbas, Yu Yu

2012-01-01

Application of a ring laser to determine the directions to the poles of Earth's rotation is considered. The maximum accuracy of determining the directions is calculated, physical and technical mechanisms that limit the accuracy are analysed, and the instrumental errors are estimated by the example of ring He — Ne lasers with Zeeman biasing. (laser applications and other topics in quantum electronics)

Pressure dependence of magnetic ordering temperatures of rare earth-Sn/sub 3/ compounds

Energy Technology Data Exchange (ETDEWEB)

Foner, S [Massachusetts Inst. of Tech., Cambridge (USA). Francis Bitter National Magnet Lab.

1979-12-01

Measurements of the hydrostatic pressure dependence of the Neel temperatures, Tsub(N), are reported for PrSn/sub 3/, NdSn/sub 3/, GdSn/sub 3/ and CeIn/sub 3/. Tsub(N) is found to increase with applied pressure for PrSn/sub 3/ and NdSn/sub 3/, whereas Tsub(N) is pressure independent within experimental error for GdSn/sub 3/ and CeIn/sub 3/. Slightly Sn-deficient RESn/sub 3/ (RE = rare earth) compounds are found consistently to be weakly ferromagnetic. The physical properties of the RESn/sub 3/ compounds exhibit analogies with the corresponding properties of dilute superconducting (LaRE)Sn/sub 3/ alloys. The high pressure data for PrSn/sub 3/ and CeIn/sub 3/ are qualitatively consistent with a 'Kondo necklace' model for magnetically ordered RE compounds with unstable 4f shells.

Pressure dependence of magnetic ordering temperatures of rare earth - Sn/sub 3/ compounds

Energy Technology Data Exchange (ETDEWEB)

DeLong, L E [Virginia Univ., Charlottesville (USA). Dept. of Physics; Guertin, R P; Foner, S

1979-12-01

Measurements of the hydrostatic pressure dependence of the Neel temperatures, Tsub(N), are reported for PrSn/sub 3/, NdSn/sub 3/, GdSn/sub 3/ and CeIn/sub 3/. Tsub(N) is found to increase with applied pressure for PrSn/sub 3/ and NdSn/sub 3/, whereas Tsub(N) is pressure independent within experimental error for GdSn/sub 3/ and CeIn/sub 3/. Slightly Sn-deficient RESn/sub 3/ (RE=rare earth) compounds are found consistently to be weakly ferromagnetic. The physical properties of the RESn/sub 3/ compounds exhibit analogies with the corresponding properties of dilute superconducting (LaRE)Sn/sub 3/ alloys. The high pressure data for PrSn/sub 3/ and CeIn/sub 3/ are qualitatively consistent with a 'Kondo necklace' model for magnetically ordered RE compounds with unstable 4f shells.

Planet Within a Planet: Rotation of the Inner Core of Earth

Science.gov (United States)

Su; Dziewonski; Jeanloz

1996-12-13

The time dependence of the orientation of Earth's inner core relative to the mantle was determined using a recently discovered 10-degree tilt in the axis of symmetry of the inner core's seismic-velocity anisotropy. Two methods of analyzing travel-time variations for rays traversing the inner core, on the basis of 29 years of data from the International Seismological Centre (1964-1992), reveal that the inner core appears to rotate about 3 degrees per year faster than the mantle. An anomalous variation in inner-core orientation from 1969 to 1973 coincides in time with a sudden change ("jerk") in the geomagnetic field.

Evaluation of sub daily satellite rainfall estimates through flash flood modelling in the Lower Middle Zambezi Basin

Directory of Open Access Journals (Sweden)

T. Matingo

2018-05-01

Full Text Available Flash floods are experienced almost annually in the ungauged Mbire District of the Middle Zambezi Basin. Studies related to hydrological modelling (rainfall-runoff and flood forecasting require major inputs such as precipitation which, due to shortage of observed data, are increasingly using indirect methods for estimating precipitation. This study therefore evaluated performance of CMORPH and TRMM satellite rainfall estimates (SREs for 30 min, 1 h, 3 h and daily intensities through hydrologic and flash flood modelling in the Lower Middle Zambezi Basin for the period 2013–2016. On a daily timestep, uncorrected CMORPH and TRMM show Probability of Detection (POD of 61 and 59 %, respectively, when compared to rain gauge observations. The best performance using Correlation Coefficient (CC was 70 and 60 % on daily timesteps for CMORPH and TRMM, respectively. The best RMSE for CMORPH was 0.81 % for 30 min timestep and for TRMM was 2, 11 % on 3 h timestep. For the year 2014 to 2015, the HEC-HMS (Hydrological Engineering Centre-Hydrological Modelling System daily model calibration Nash Sutcliffe efficiency (NSE for Musengezi sub catchment was 59 % whilst for Angwa it was 55 %. Angwa sub-catchment daily NSE results for the period 2015–2016 was 61 %. HEC-RAS flash flood modeling at 100, 50 and 25 year return periods for Angwa sub catchment, inundated 811 and 867 ha for TRMM rainfall simulated discharge at 3 h and daily timesteps, respectively. For CMORPH generated rainfall, the inundation was 818, 876, 890 and 891 ha at daily, 3 h, 1 h and 30 min timesteps. The 30 min time step for CMORPH effectively captures flash floods with the measure of agreement between simulated flood extent and ground control points of 69 %. For TRMM, the 3 h timestep effectively captures flash floods with coefficient of 67 %. The study therefore concludes that satellite products are most effective in capturing localized

Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures using one-pot hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Gao, Guo, E-mail: guogao@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Qiang; Cheng, Xin-Bing [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Sun, Rongjin [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Shapter, Joseph G., E-mail: joe.shapter@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, Bedford Park, Adelaide 5042 (Australia); Yin, Ting [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Cui, Daxiang, E-mail: dxcui@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2015-11-15

Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe{sub 3}O{sub 4}, CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm. The GO sheets and CNTs are interlinked by ultrafine Fe{sub 3}O{sub 4} nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe{sub 3}O{sub 4} hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites can recover to 1023.9 mAhg{sup −1}, indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites are superior to CNTs-GO-Fe{sub 3}O{sub 4} and CNTs-GO-Fe{sub 3}O{sub 4}-Er hybrid structures. - Graphical abstract: One-pot hydrothermal method for synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures as anode materials of LIBs have been reported. - Highlights: • We report the synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures. • The hybrid structures can improve the cycling stability of lithium storage. • As for anode materials, the broad satellite peak can be completely eliminated. • When the rate return back to 0.1 C, the capacity can recover to 1023.9 mAhg{sup −1}. • After 500

Rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation

Energy Technology Data Exchange (ETDEWEB)

Teshima, Hidekazu [Nippon Steel Corp., Kawasaki, Kanagawa (Japan). Advanced Materials and Technology Research Labs.; Tawara, Taichi; Shimada, Ryuichi

1997-08-01

This paper describes the experimental results for the rotational loss of a ring-shaped flywheel supported by high T{sub c} superconducting levitation. Superconducting levitation is appropriate for rotating a ring-shaped flywheel which has neither shaft nor hub because it is a non-contact and automatically stable levitation without any control systems. The rotational loss has been investigated using a small-scaled experimental machine consisting of 16 bulk superconductors 46 mm in diameter and a ring-shaped flywheel about 300 mm in diameter. The rotational loss decreased as the levitation gap height increased. In low-speed rotational regions, the rotational loss was in proportion to the rotation speed and depended more on the levitation gap. In high-speed rotational regions, the rotational loss was in proportion to the third power of the rotation speed and depended less on the levitation gap. The cubic rotational loss in He was reduced to one-fifth of that in air. The magnetic field pinned in bulk superconductors induces a loss in the materials composing the ring-shaped flywheel. The rotational loss of a ring-shaped flywheel supported by superconducting levitation can be reduced by improving the uniformity of the magnetic fields along the ring, enlargement of the bulk superconductor(s), and densely arranging the bulk superconductors. (author)

Computer modelling of defect structure and rare earth doping in LiCaAlF sub 6 and LiSrAlF sub 6

CERN Document Server

Amaral, J B; Valerio, M E G; Jackson, R A

2003-01-01

This paper describes a computational study of the mixed metal fluorides LiCaAlF sub 6 and LiSrAlF sub 6 , which have potential technological applications when doped with a range of elements, especially those from the rare earth series. Potentials are derived to represent the structure and properties of the undoped materials, then defect properties are calculated, and finally solution energies for rare earth elements are calculated, enabling preferred dopant sites and charge compensation mechanisms to be predicted.

Rare earth oxide reinforced Al{sub 2}O{sub 3}-TiO{sub 2} ceramics for inert coating of metallic parts for petroleum extraction

Energy Technology Data Exchange (ETDEWEB)

Yadava, Yoggendra Prasad; Rego, Sheila Alves Bezerra da Costa; Ferreira, Ricardo Artur Sanguinetti [Universidade Federal de Pernambuco (UFPE), Recife (Brazil)

2012-07-01

Recent findings of largest known pre-salt petroleum reservoir in Brazil have created an intense demand for new materials capable of withstanding direct contact with the crude petroleum as it is a highly corrosive and chemically reactive fluid. Petroleum drilling equipment, storage tanks and transportation systems suffer from constant physical stress caused by chemical attack of crude petroleum on its structure. Ceramics are materials with high chemical stability in hostile environment and therefore can be used as an inert coating material to resolve such problems. To date, ceramics based on alumina are most widely used in practice where there is demand for high mechanical strength and high fracture toughness. However intrinsic fragility of ceramics is still a fatal factor for their use in mechanical structures. To improve these characteristics, usually ceramics are reinforced with one or more ceramic additives. Mechanical properties of alumina based ceramics improve considerably with the addition of TiO{sub 2}, TiN, ZrO{sub 2} etc. ceramic additives. Nucleation and propagation of cracks is a major problem for ceramic coating applications. Initial studies show that addition of small percentages of rare earth oxides can increase the toughness of the alumina based ceramics. In the present work, we have produced rare-earth oxide (CeO{sub 2}) reinforced Al{sub 2}O{sub 3}-TiO{sub 2} ceramics in proportions of 5-20 wt% TiO{sub 2} and 2%wt% CeO{sub 2} through thermomechanical processing and sintering techniques and studied there microstructural characteristics and mechanical properties. To evaluate the potential of these ceramics as inert coatings for crude petroleum extraction, storage and transportation systems, we have studied the physic-chemical and mechanical stability of these ceramics in crude petroleum environment. Our studies presented satisfactory results in terms of physic-chemical and mechanical stability of these materials for the use of 2wt% of CeO{sub 2

Exoplanet dynamics. Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars.

Science.gov (United States)

Leconte, Jérémy; Wu, Hanbo; Menou, Kristen; Murray, Norman

2015-02-06

Planets in the habitable zone of lower-mass stars are often assumed to be in a state of tidally synchronized rotation, which would considerably affect their putative habitability. Although thermal tides cause Venus to rotate retrogradely, simple scaling arguments tend to attribute this peculiarity to the massive Venusian atmosphere. Using a global climate model, we show that even a relatively thin atmosphere can drive terrestrial planets' rotation away from synchronicity. We derive a more realistic atmospheric tide model that predicts four asynchronous equilibrium spin states, two being stable, when the amplitude of the thermal tide exceeds a threshold that is met for habitable Earth-like planets with a 1-bar atmosphere around stars more massive than ~0.5 to 0.7 solar mass. Thus, many recently discovered terrestrial planets could exhibit asynchronous spin-orbit rotation, even with a thin atmosphere. Copyright © 2015, American Association for the Advancement of Science.

Characteristics of sub-daily precipitation extremes in observed data and regional climate model simulations

Science.gov (United States)

Beranová, Romana; Kyselý, Jan; Hanel, Martin

2018-04-01

The study compares characteristics of observed sub-daily precipitation extremes in the Czech Republic with those simulated by Hadley Centre Regional Model version 3 (HadRM3) and Rossby Centre Regional Atmospheric Model version 4 (RCA4) regional climate models (RCMs) driven by reanalyses and examines diurnal cycles of hourly precipitation and their dependence on intensity and surface temperature. The observed warm-season (May-September) maxima of short-duration (1, 2 and 3 h) amounts show one diurnal peak in the afternoon, which is simulated reasonably well by RCA4, although the peak occurs too early in the model. HadRM3 provides an unrealistic diurnal cycle with a nighttime peak and an afternoon minimum coinciding with the observed maximum for all three ensemble members, which suggests that convection is not captured realistically. Distorted relationships of the diurnal cycles of hourly precipitation to daily maximum temperature in HadRM3 further evidence that underlying physical mechanisms are misrepresented in this RCM. Goodness-of-fit tests indicate that generalised extreme value distribution is an applicable model for both observed and RCM-simulated precipitation maxima. However, the RCMs are not able to capture the range of the shape parameter estimates of distributions of short-duration precipitation maxima realistically, leading to either too many (nearly all for HadRM3) or too few (RCA4) grid boxes in which the shape parameter corresponds to a heavy tail. This means that the distributions of maxima of sub-daily amounts are distorted in the RCM-simulated data and do not match reality well. Therefore, projected changes of sub-daily precipitation extremes in climate change scenarios based on RCMs not resolving convection need to be interpreted with caution.

Self-propagating high temperature synthesis, structural morphology and magnetic interactions in rare earth Ho{sup 3+} doped CoFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Lohar, K.S. [Materials Research Laboratory, Srikrishna Mahavidyalaya Gunjoti, Omerga, Osmanabad 413 613, MS (India); Pachpinde, A.M.; Langade, M.M. [Department of Chemistry, Jawahar Art Science and Commerce College Andur, Osmanabad, MS (India); Kadam, R.H. [Materials Research Laboratory, Srikrishna Mahavidyalaya Gunjoti, Omerga, Osmanabad 413 613, MS (India); Shirsath, Sagar E., E-mail: shirsathsagar@hotmail.com [Spin Device Technology Center, Department of Information Engineering, Shinshu University, Nagano 380-8553 (Japan)

2014-08-01

Highlights: • Rare earth Ho{sup 3+} substituted CoFe{sub 2}O{sub 4.} • XRD and IR spectra reveal the spinel structure. • Magnetization and coercivity increased with Ho{sup 3+} substitution. - Abstract: Substitution effect of rare earth trivalent Ho{sup 3+} ions on the composition, Ho{sub x}CoFe{sub 2−x}O{sub 4}, with x varying from 0.0 to 0.1 in steps of 0.025 using sol–gel auto combustion route has been investigated. Examination of X-ray diffraction (XRD) patterns shows that all the samples consisted of ferrite phases of typical spinel cubic structure, and when Ho{sup 3+} ion content was x ⩾ 0.075, orthoferrite–HoFeO{sub 3} phase was detected. The micro and nanostructure of the synthesized Ho doped CoFe{sub 2}O{sub 4} ferrites were investigated by scanning and transmission electron microscopy respectively. With increasing doping content of Ho{sup 3+} ions, the lattice constant, particle size and bulk density increased, and after an increase to its maximum value, the sample particle size and density dropped down. Cation distribution estimated from XRD patter revealed that the Co{sup 2+} and Ho{sup 3+} ions prefer to occupy octahedral B-site whereas Fe{sup 3+} ions are distributed over tetra- and octa-hedral site. Oxygen positional parameter shows larger values than its ideal value. The analysis of magnetic properties revealed that the saturation magnetization and coercivity of CoFe{sub 2}O{sub 4} increased with the rare earth Ho{sup 3+} substitution.

Radiation-pressure-driven sub-Keplerian rotation of the disc around the AGB star L2 Pup

Science.gov (United States)

Haworth, Thomas J.; Booth, Richard A.; Homan, Ward; Decin, Leen; Clarke, Cathie J.; Mohanty, Subhanjoy

2018-01-01

We study the sub-Keplerian rotation and dust content of the circumstellar material around the asymptotic giant branch (AGB) star L2 Puppis. We find that the thermal pressure gradient alone cannot explain the observed rotation profile. We find that there is a family of possible dust populations for which radiation pressure can drive the observed sub-Keplerian rotation. This set of solutions is further constrained by the spectral energy distribution (SED) of the system, and we find that a dust-to-gas mass ratio of ∼10-3 and a maximum grain size that decreases radially outwards can satisfy both the rotation curve and SED. These dust populations are dynamically tightly coupled to the gas azimuthally. However, grains larger than ∼ 0.5 μm are driven outwards radially by radiation pressure at velocities ∼5 km s-1, which implies a dust replenishment rate of ∼3 × 10-9 M⊙ yr-1. This replenishment rate is consistent with observational estimates to within uncertainties. Coupling between the radial motion of the dust and gas is weak and hence the gas does not share in this rapid outward motion. Overall, we conclude that radiation pressure is a capable and necessary mechanism to explain the observed rotation profile of L2 Pup, and offers other additional constraints on the dust properties.

Transverse and Longitudinal Doppler Effects of the Sunbeam Spectra and Earth-Self Rotation and Orbital Velocities, the Mass of the Sun and Others

OpenAIRE

Nam, Sang Boo

2009-01-01

The transverse and longitudinal Doppler effects of the sunbeam spectra are shown to result in the earth parameters such as the earth-self rotation and revolution velocities, the earth orbit semi-major axis, the earth orbital angular momentum, the earth axial tilt, the earth orbit eccentricity, the local latitude and the mass of the sun. The sunbeam global positioning scheme is realized, including the earth orbital position. PACS numbers: 91.10.Fc, 95.10.Km, 91.10.Da, 91.10.Jf.

Earth rotation parameter and variation during 2005–2010 solved with LAGEOS SLR data

Directory of Open Access Journals (Sweden)

Yi Shen

2015-01-01

Full Text Available Time series of Earth rotation parameters were estimated from range data measured by the satellite laser ranging technique to the Laser Geodynamics Satellites (LAGEOS-1/2 through 2005 to 2010 using the dynamic method. Compared with Earth orientation parameter (EOP C04, released by the International Earth Rotation and Reference Systems Service, the root mean square errors for the measured X and Y of polar motion (PM and length of day (LOD were 0.24 and 0.25 milliarcseconds (mas, and 0.068 milliseconds (ms, respectively. Compared with ILRSA EOP, the X and Y of PM and LOD were 0.27 and 0.30 mas, and 0.054 ms, respectively. The time series were analyzed using the wavelet transformation and least squares methods. Wavelet analysis showed obvious seasonal and interannual variations of LOD, and both annual and Chandler variations of PM; however, the annual variation could not be distinguished from the Chandler variation because the two frequencies were very close. The trends and periodic variations of LOD and PM were obtained in the least squares sense, and PM showed semi-annual, annual, and Chandler periods. Semi-annual, annual, and quasi-biennial cycles for LOD were also detected. The trend rates of PM in the X and Y directions were 3.17 and −1.60 mas per year, respectively, and the North Pole moved to 26.8°E relative to the crust during 2005–2010. The trend rate of the LOD change was 0.028 ms per year.

Structural, optical and spectroscopical investigations into rare-earths perowskites RGaO{sub 3} (R=La, Pr, Nd) and NdBa-2Cu{sub 3}O{sub 7-{delta}}; Strukturelle, optische und spektroskopische Untersuchungen von Seltenen-Erd-Perowskiten RGaO{sub 3} (R=La, Pr, Nd) und NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}}

Energy Technology Data Exchange (ETDEWEB)

Marti, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1995-07-01

In this work I was engaged in rare-earth perovskites. Primarily I investigated the structure of the rare-earth gallates RGaO{sub 3} (R=La, Pr, Nd) as a function of the temperature by means of neutron diffraction and x-ray diffraction. As the high-T{sub c} superconductors these compounds belong to the family of the perovskites, they are ferroelastic and centro-symmetric. Because of the lanthanide-contraction all lattice constants and distortion parameters change systematically. The rare-earth-gallates RGaO{sub 3} (R=La, Pr, Nd) are promising substrates for epitaxy of high-T{sub c} superconductors like RBa{sub 2}Cu{sub 3}OO{sub 7-{delta}} because of their structure parameters and expansion coefficients. I succeeded in producing plane-parallel single-domain crystals by means of uniaxial stress. The first order phase transition was observable only in LaGaO{sub 3}. A structurally phase transition from orthorhombic to rhombohedral symmetry (high-temperature phase) occurs at 423 K. The hysteresis of the phase transition temperature of about 1.5 K was measured with single-domain crystals by means of neutron diffraction and polarized light microscopy. In NdGaO{sub 3} we determined the long-range, three-dimensional, antiferromagnetic ordering of the Nd{sup 3+}-ions below the ordering temperature at T{sub N}=0.97 K by means of magnetic neutron diffraction. The spin configuration could be described by a (--c{sub z})-mode. Measurements of the magnetic susceptibility confirm the easy direction of magnetization to be the c-axis. Below 300mK an additional nuclear spin polarization due to the hyperfine-interaction appears parallel to the electronic spins, which amounts to 70% at 10mK. Further I investigated the optical properties of the rare-earth gallates. The birefringence of plane-parallel, polished single-domain crystals with thickness up to 300 {mu}m was measured by means of orthoscopy and conoscopy. (author) figs., tabs., refs.

The zonal tidal effect on the variation in the rotation rate of the Earth with a fluid core II. Numerical calculation and comparisons

Science.gov (United States)

Zhang, Han-Wei; Zheng, Yong; Du, Lan; Pan, Guan-Song

The tidal variation in Earth rotation rate is a periodical response to solar-lunar tide generating potential (TGP). Some theoretical formulae are given here based on Doodson development of TGP including the variations in Earth rotation rate, LOD and UT1. Finally the zonal tidal effect on the variation in the fluid core Earth rotation rate is calculated according to the formula deduced by Xi Qinwen (1995). The calculation shows that the results in this paper are well consistent with the ones in IERS (96), which indicates the correctness of the theoretical formula we deduced. It is also shown that the effects from the high frequency parts are relatively small, within the observing precision so far; relatively large effects due to the lower parts, which should be able to be seperated from the observed data, are actually difficult to make because of the influence from some non-tidal factors as well as short time span data.

Syntheses, crystal structures and photoluminescence properties of two rare-earth molybdates CsLn(MoO{sub 4}){sub 2} (Ln=Eu, Tb)

Energy Technology Data Exchange (ETDEWEB)

Zhao, Dan; Ma, Fa-Xue; Liu, Bao-Zhong; Fan, Yun-Chang; Han, Xue-Feng; Zhang, Lei; Nie, Cong-Kui [Henan Polytechnic Univ. (China). College of Chemistry and Chemical Engineering

2018-04-01

Single crystals of two cesium rare-earth molybdates CsLn(MoO{sub 4}){sub 2} (Ln=Eu, Tb) have been prepared using the high temperature molten salt (flux) method. Single-crystal X-ray diffraction analyses reveal that they crystallize in the orthorhombic space group Pccm (No. 49) and features a 2D layer structure that is composed of [Ln(MoO{sub 4}){sub 2}]{sub ∞} and [Cs]{sub ∞} layers. Under near-UV light excitation, emission spectrum of CsEu(MoO{sub 4}){sub 2} consists of several sharp lines due to the characteristic electronic transitions of Eu{sup 3+} ions, whereas CsTb(MoO{sub 4}){sub 2} exhibits characteristic green emission of Tb{sup 3+} ions.

CeNi{sub 3}-type rare earth compounds: crystal structure of R{sub 3}Co{sub 7}Al{sub 2} (R=Y, Gd–Tm) and magnetic properties of {Gd–Er}{sub 3}Co{sub 7}Al{sub 2}, {Tb, Dy}{sub 3}Ni{sub 8}Si and Dy{sub 3}Co{sub 7.68}Si{sub 1.32}

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-1, Moscow 119991 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600 036 (India); Quezado, S.; Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

2017-03-15

The crystal structure of new CeNi{sub 3}-type {Y, Gd–Tm}{sub 3}Co{sub 7}Al{sub 2} (P63/mmc. N 194, hP24) compounds has been established using powder X-ray diffraction studies. The magnetism of Tb{sub 3}Ni{sub 8}Si and Dy{sub 3}Ni{sub 8}Si is dominated by rare earth sublattice and the magnetic properties of R{sub 3}Co{sub 7}Al{sub 2} (R =Gd–Er) and Dy{sub 3}Co{sub 7.68}Si{sub 1.32} are determined by both rare earth and cobalt sublattices. Magnetization data indicate ferromagnetic ordering of {Tb, Dy}{sub 3}Ni{sub 8}Si at 32 K and 21 K, respectively. Gd{sub 3}Co{sub 7}Al{sub 2} and Tb{sub 3}Co{sub 7}Al{sub 2} exhibit ferromagnetic ordering at 309 K and 209 K, respectively, whereas Dy{sub 3}Co{sub 7}Al{sub 2}, Ho{sub 3}Co{sub 7}Al{sub 2}, Er{sub 3}Co{sub 7}Al{sub 2} and Dy{sub 3}Co{sub 7.68}Si{sub 1.32} show a field dependent ferromagnetic-like ordering at 166 K, 124 K, 84 K and 226 K, respectively followed by a low temperature transition at 34 K for Dy{sub 3}Co{sub 7}Al{sub 2}, 18 K for Ho{sub 3}Co{sub 7}Al{sub 2}, 56 K for Er{sub 3}Co{sub 7}Al{sub 2}, 155 K and 42 K for Dy{sub 3}Co{sub 7.68}Si{sub 1.32}. Among these compounds, Dy{sub 3}Ni{sub 8}Si shows largest magnetocaloric effect (isothermal magnetic entropy change) of −11.6 J/kg·K at 18 K in field change of 50 kOe, whereas Tb{sub 3}Co{sub 7}Al{sub 2}, Dy{sub 3}Co{sub 7}Al{sub 2} and Dy{sub 3}Co{sub 7.68}Si{sub 1.32} exhibit best permanent magnet properties in the temperature range of 2–5 K with remanent magnetization of 11.95 μ{sub B}/fu, 12.86 μ{sub B}/fu and 14.4 μ{sub B}/fu, respectively and coercive field of 3.0 kOe, 1.9 kOe and 4.4 kOe, respectively. - Highlights: • {Y, Gd–Tm}{sub 3}Co{sub 7}Al{sub 2} compounds crystallize in the CeNi{sub 3}-type structure. • {Gd-Er}{sub 3}Co{sub 7}Al{sub 2} show ferrimagnetic ordering at 309 K, 209 K, 166 K, 124 K and 84 K. • Dy{sub 3}Co{sub 7.68}Si{sub 1.32} exhibits magnetic transitions at 226 K, 155 K and 42 K. • {Tb-Er}{sub 3}Co{sub 7}Al{sub 2

Synthesis, structures, and luminescent properties of sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4} (Ln = Sm, Eu, Gd, Tb, Dy, and Ho)

Energy Technology Data Exchange (ETDEWEB)

Charkin, Dmitri O.; Dorofeev, Sergey G.; Berdonosov, Peter S.; Dolgikh, Valery A. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Zitzer, Sabine; Greiner, Stefan; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Olenev, Andrei V. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Sine Theta Ltd., Moscow (Russian Federation)

2017-11-17

Six sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, isostructural to Na{sub 2}Y{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, were synthesized by flux techniques and characterized by single-crystal XRD. The compounds crystallize in the monoclinic space group C2/c with lattice constants a = 23.967(1), b = 5.6342(3), c = 16.952(1) Aa, β = 134.456(5) for Ln = Sm, a = 23.932(2), b = 5.6044(5), c = 17.134(1) Aa, β = 135.151(6) for Ln = Eu, a = 23.928(1), b = 5.5928(1), c = 17.1133(8) Aa, β = 135.366(3) for Ln = Gd, a = 23.907(1), b = 5.569(3), c = 16.745(1) Aa, β = 134.205(3) for Ln = Tb, a = 23.870(1), b = 5.547(3), c = 16.665(1) Aa, β = 134.102(3) for Ln = Dy, and a = 23.814(1), b = 5.526(3), c = 16.626(1) Aa, β = 134.016(3) for Ln = Ho and Z = 4. Their crystal structure can be considered as a framework built of intergrowing Ln-O and Na-(O,Cl) slabs with channel walls decorated by tellurium atoms of [TeO{sub 3}]{sup 2-} groups. The luminescent properties of the new compounds due to the Ln{sup 3+} cations are described and discussed. We also discuss the crystal chemistry of various alkali-metal rare-earth metal(III) halide oxochalcogenates(IV). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

PRE-SUPERNOVA EVOLUTION OF ROTATING SOLAR METALLICITY STARS IN THE MASS RANGE 13-120 M {sub Sun} AND THEIR EXPLOSIVE YIELDS

Energy Technology Data Exchange (ETDEWEB)

Chieffi, Alessandro [Istituto Nazionale di Astrofisica-Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Limongi, Marco, E-mail: alessandro.chieffi@inaf.it, E-mail: marco.limongi@oa-roma.inaf.it [Centre for Stellar and Planetary Astrophysics, School of Mathematical Sciences, P.O. Box 28M, Monash University, Victoria 3800 (Australia)

2013-02-10

We present the first set of a new generation of models of massive stars with a solar composition extending between 13 and 120 M {sub Sun }, computed with and without the effects of rotation. We included two instabilities induced by rotation: the meridional circulation and the shear instability. We implemented two alternative schemes to treat the transport of the angular momentum: the advection-diffusion formalism and the simpler purely diffusive one. The full evolution from the pre-main sequence up to the pre-supernova stage is followed in detail with a very extended nuclear network. The explosive yields are provided for a variety of possible mass cuts and are available at the Web site http://www.iasf-roma.inaf.it/orfeo/public{sub h}tml. We find that both the He and the CO core masses are larger than those of their non-rotating counterparts. Also the C abundance left by the He burning is lower than in the non-rotating case, especially for stars with an initial mass of 13-25 M {sub Sun }, and this affects the final mass-radius relation, basically the final binding energy, at the pre-supernova stage. The elemental yields produced by a generation of stars rotating initially at 300 km s{sup -1} do not change substantially with respect to those produced by a generation of non-rotating massive stars, the main differences being a slight overproduction of the weak s-component and a larger production of F. Since rotation also affects the mass-loss rate, either directly or indirectly, we find substantial differences in the lifetimes as O-type and Wolf-Rayet subtypes between the rotating and non-rotating models. The maximum mass exploding as Type IIP supernova ranges between 15 and 20 M {sub Sun} in both sets of models (this value depends basically on the larger mass-loss rates in the red supergiant phase due to the inclusion of the dust-driven wind). This limiting value is in remarkably good agreement with current estimates.

Prediction of earth rotation parameters based on improved weighted least squares and autoregressive model

Directory of Open Access Journals (Sweden)

Sun Zhangzhen

2012-08-01

Full Text Available In this paper, an improved weighted least squares (WLS, together with autoregressive (AR model, is proposed to improve prediction accuracy of earth rotation parameters(ERP. Four weighting schemes are developed and the optimal power e for determination of the weight elements is studied. The results show that the improved WLS-AR model can improve the ERP prediction accuracy effectively, and for different prediction intervals of ERP, different weight scheme should be chosen.

Chromospheric rotation. II. Dependence on the size of chromospheric features

Energy Technology Data Exchange (ETDEWEB)

Azzarelli, L; Casalini, P; Cerri, S; Denoth, F [Consiglio Nazionale delle Ricerche, Pisa (Italy). Ist. di Elaborazione della Informazione

1979-08-01

The dependence of solar rotation on the size of the chromospheric tracers is considered. On the basis of an analysis of Ca II K/sub 3/ daily filtergrams taken in the period 8 May-14 August, 1972, chromospheric features can be divided into two classes according to their size. Features with size falling into the range 24 000-110 000 km can be identified with network elements, while those falling into the range 120 000-300 000 km with active regions, or brightness features of comparable size present at high latitudes. The rotation rate is determined separately for the two families of chromospheric features by means of a cross-correlation technique directly yields the average daily displacement of tracers due to rotation. Before computing the cross-correlation functions, chromospheric brightness data have been filtered with appropriate bandpass and highpass filters for separating spatial periodicities whose wavelengths fall into the two ranges of size, characteristic of the network pattern and of the activity centers. A difference less than 1% of the rotation rate of the two families of chromospheric features has been found. This is an indication for a substantial corotation at chromospheric levels of different short-lived features, both related to solar activity and controlled by the convective supergranular motions.

Competing Structural Instabilities in the Ruddlesden–Popper Derivatives HRTiO4 (R = Rare Earths): Oxygen Octahedral Rotations Inducing Noncentrosymmetricity and Layer Sliding Retaining Centrosymmetricity

International Nuclear Information System (INIS)

Sen Gupta, Arnab; Akamatsu, Hirofumi; Brown, Forrest G.; Nguyen, Minh An T.

2016-01-01

We report the discovery of noncentrosymmetry in the family of HRTiO 4 (R = Eu, Gd, Dy) layered oxides possessing a Ruddlesden-Popper derivative structure, by second harmonic generation and synchrotron x-ray diffraction with the support of density functional theory calculations. These oxides were previously thought to possess inversion symmetry. Here, inversion symmetry is broken by oxygen octahedral rotations, a mechanism that is not active in simple perovskites. We discover a competition between oxygen octahedral rotations and sliding of the octahedral perovskite blocks at the OH layers. For the smaller rare earth ions, R = Eu, Gd, Dy, which favor the octahedral rotations, noncentrosymmetry is present but the sliding at the OH layer is absent. For the larger rare earth ions, R = Nd and Sm, the octahe-dral rotations are absent, but sliding of the octahedral blocks at the OH layer is present, likely to optimize the hydrogen bond length arising from the directional nature of these bonds in the crystal structure. The study reveals a new mechanism for inducing noncentrosymmetry in layered oxides, and chemical-structural effects related to rare earth ion size and hydrogen bonding that can turn this mechanism on and off. In conclusion, we construct a complete phase diagram of temperature versus rare earth ionic radius for the HRTiO 4 family.

Long-Term Evaluation of Ocean Tidal Variation Models of Polar Motion and UT1

Science.gov (United States)

Karbon, Maria; Balidakis, Kyriakos; Belda, Santiago; Nilsson, Tobias; Hagedoorn, Jan; Schuh, Harald

2018-04-01

Recent improvements in the development of VLBI (very long baseline interferometry) and other space geodetic techniques such as the global navigation satellite systems (GNSS) require very precise a-priori information of short-period (daily and sub-daily) Earth rotation variations. One significant contribution to Earth rotation is caused by the diurnal and semi-diurnal ocean tides. Within this work, we developed a new model for the short-period ocean tidal variations in Earth rotation, where the ocean tidal angular momentum model and the Earth rotation variation have been setup jointly. Besides the model of the short-period variation of the Earth's rotation parameters (ERP), based on the empirical ocean tide model EOT11a, we developed also ERP models, that are based on the hydrodynamic ocean tide models FES2012 and HAMTIDE. Furthermore, we have assessed the effect of uncertainties in the elastic Earth model on the resulting ERP models. Our proposed alternative ERP model to the IERS 2010 conventional model considers the elastic model PREM and 260 partial tides. The choice of the ocean tide model and the determination of the tidal velocities have been identified as the main uncertainties. However, in the VLBI analysis all models perform on the same level of accuracy. From these findings, we conclude that the models presented here, which are based on a re-examined theoretical description and long-term satellite altimetry observation only, are an alternative for the IERS conventional model but do not improve the geodetic results.

Trends in characteristics of sub-daily heavy precipitation and rainfall erosivity in the Czech Republic

Czech Academy of Sciences Publication Activity Database

Hanel, M.; Pavlásková, A.; Kyselý, Jan

2016-01-01

Roč. 36, č. 4 (2016), s. 1833-1845 ISSN 0899-8418 Institutional support: RVO:67179843 Keywords : sub-daily precipitation * fainfall events * erosivity * extremes * climate variability * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.760, year: 2016

Monitoring daily and sub-daily variations in crustal strain with seismic arrays

Science.gov (United States)

Mao, S.; Campillo, M.; van der Hilst, R. D.; Brenguier, F.; Hillers, G.

2017-12-01

We demonstrate that we can monitor deformation of the shallow crust (with hourly temporal resolution) directly with seismic waves, by measuring relative seismic wave speed changes (dv/v) due to relatively known periodical forcing (tides and changes in atmospheric temperature) at Piton de la Fournaise Volcano (PdF), La Réunion. We use ambient seismic noise recorded (for one month) at VolcArray, an experiment with three arrays of 49 vertical-component geophones deployed on a 7x7 grid of approximately 80 m spacing. Through noise-based coda wave interferometry we infer for each array the average relative changes in propagation speed of seismic waves (dv/v) as a function of time, which relate to temporal changes in medium properties within 100m depth. The variations in dv/v ( 0.05%) on time-scales longer than a day are best explained by effects of precipitation on pore pressure. In contrast, the (weaker) daily and sub-daily fluctuations of dv/v ( 0.01%) are likely to be caused by tidal and thermal effects. We verify that the inferred variations of dv/v are unrelated to spatiotemporal changes of noise wavefields. We further compare the power spectrum of dv/v with spectra of simulated tide-induced volumetric strain, temperature records, very broadband (VBB) seismograms, and borehole tilt records. In all five types of data, dominant peaks are found at around diurnal, semi-diurnal, and ter-diurnal frequencies. A comparison of phase and spectra of the data suggests that the tidal and thermal effects on dv/v are of similar magnitude but vary with frequency. Theoretical modeling of tide- and temperature-induced strain in different frequency bands agrees with the relative magnitude of the two effects on dv/v from passive monitoring.

Phase separation and exchange bias effect in Ca doped EuCrO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Deng, Dongmei, E-mail: dmdeng@shu.edu.cn [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Wang, Xingyu; Zheng, Jiashun; Qian, Xiaolong [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Yu, Dehong; Sun, Dehui [Bragg Institute, Australian Nuclear Science and Technology Organization, Kirrawee DC, NSW 2232 (Australia); Jing, Chao [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Lu, Bo [Analysis and Measurement Center and Laboratory for Microstructures of Shanghai University, Shanghai 200444 (China); Kang, Baojuan; Cao, Shixun; Zhang, Jincang [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China)

2015-12-01

The rare-earth chromites have attracted increasing interests in recent years, as a member of a few single-phase multiferroic materials. We studied the structure and magnetic property of a series of Ca-doped EuCrO{sub 3} samples by using X-ray powder diffraction and Physical Property Measurement System. Phase separation, rotation of magnetization in M(T) curve and exchange bias effect have been identified. The Eu{sub 0.7}Ca{sub 0.3}CrO{sub 3} polycrystalline sample may be intrinsically phase-separated, with Cr{sup 3+}-rich, Cr{sup 4+}-rich canted antiferromagnetic regions surrounded by spin glass-like frustrated phase, resulting in several magnetic features including: (1) a broad and slow increase of M(T) curve with the decrease of temperature; (2) rotation of magnetization with increasing cooling field; (3) exchange bias and glassy magnetism. The rotation of magnetization is ascribed to the rotation of the moment of Cr{sup 4+}-rich regions, arising from the competition between exchange coupling energy and magnetostatic energy. The exchange bias effect suggests the formation of weak ferromagnetic unidirectional anisotropy during field cooling, due to the exchange coupling among weak ferromagnetic domains and surrounding spin glass-like regions. This result helps understanding the interaction among different magnetic domains and phases in a complex system. - Highlights: • Exchange bias effect and glassy magnetism were observed in Eu{sub 0.7}Ca{sub 0.3}CrO{sub 3}. • Rotation of the moments of Cr{sup 4+}-rich regions result in the rotation of magnetization in M(T) curve. • Spin glass-like regions contribute to the observed exchange bias effect.

Ocean tide models for satellite geodesy and Earth rotation

Science.gov (United States)

Dickman, Steven R.

1991-01-01

A theory is presented which predicts tides in turbulent, self-gravitating, and loading oceans possessing linearized bottom friction, realistic bathymetry, and continents (at coastal boundaries no-flow conditions are imposed). The theory is phrased in terms of spherical harmonics, which allows the tide equations to be reduced to linear matrix equations. This approach also allows an ocean-wide mass conservation constraint to be applied. Solutions were obtained for 32 long and short period luni-solar tidal constituents (and the pole tide), including the tidal velocities in addition to the tide height. Calibrating the intensity of bottom friction produces reasonable phase lags for all constituents; however, tidal amplitudes compare well with those from observation and other theories only for long-period constituents. In the most recent stage of grant research, traditional theory (Liouville equations) for determining the effects of angular momentum exchange on Earth's rotation were extended to encompass high-frequency excitations (such as short-period tides).

Conditions for oceans on Earth-like planets orbiting within the habitable zone: importance of volcanic CO{sub 2} degassing

Energy Technology Data Exchange (ETDEWEB)

Kadoya, S. [Department of Earth and Planetary Science, The University of Tokyo, Kiban Bldg. 408, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Tajika, E., E-mail: kadoya@astrobio.k.u-tokyo.ac.jp, E-mail: tajika@astrobio.k.u-tokyo.ac.jp [Department of Complexity Science and Engineering, The University of Tokyo, Kiban Bldg. 409, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)

2014-08-01

Earth-like planets in the habitable zone (HZ) have been considered to have warm climates and liquid water on their surfaces if the carbonate-silicate geochemical cycle is working as on Earth. However, it is known that even the present Earth may be globally ice-covered when the rate of CO{sub 2} degassing via volcanism becomes low. Here we discuss the climates of Earth-like planets in which the carbonate-silicate geochemical cycle is working, with focusing particularly on insolation and the CO{sub 2} degassing rate. The climate of Earth-like planets within the HZ can be classified into three climate modes (hot, warm, and snowball climate modes). We found that the conditions for the existence of liquid water should be largely restricted even when the planet is orbiting within the HZ and the carbonate-silicate geochemical cycle is working. We show that these conditions should depend strongly on the rate of CO{sub 2} degassing via volcanism. It is, therefore, suggested that thermal evolution of the planetary interiors will be a controlling factor for Earth-like planets to have liquid water on their surface.

Magnetic sublattices in Np{sub 2}Co{sub 17} and Np{sub 2}Ni{sub 17}

Energy Technology Data Exchange (ETDEWEB)

Colineau, E., E-mail: eric.colineau@ec.europa.eu; Hen, A. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany); Sanchez, J.-P. [CEA, INAC-SPSMS (France); Griveau, J.-C.; Magnani, N.; Eloirdi, R. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany); Halevy, I. [Ben Gurion University, Nuclear Engineering Department (Israel); Gaczyński, P. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany); Orion, I. [Ben Gurion University, Nuclear Engineering Department (Israel); Shick, A. B. [Institute of Physics, ASCR (Czech Republic); Caciuffo, R. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany)

2016-12-15

Rare-earth-based compounds R{sub 2}T{sub 17} (R=Rare earth; T=Transition metal) have been extensively studied and developed for applications as permanent magnets. The actinide-based analogues, however, are much less documented and we report here about the magnetic properties of Np{sub 2}Co{sub 17} and Np{sub 2}Ni{sub 17}, as inferred from {sup 237}Np Mössbauer spectroscopy, the best resonance in actinides, and specific heat.

Activity of RE/sub 2/O/sub 3/ in liquid La/sub 2/O/sub 3/-Al/sub 2/O/sub 3/-CaF/sub 2/ and Ce/sub 2/O/sub 3/-CaO-CaF/sub 2/ slags

International Nuclear Information System (INIS)

Changzhen, W.; Shuqing, Y.; Qieng, D.

1985-01-01

In the course of electro-slag refining, if the slag contains rare earth oxides, the amount of rare earth introduced to the steel depends on the composition of the slag and other conditions. The main aim of this investigation is to study the activity of RE/sub 2/O/sub 3/ in the electro-slags of various compositions. One is the La/sub 2/O/sub 3/-CaO-CaF/sub 2/ ternary slag system and the other is the Ce/sub 2/O/sub 3/-CaO-CaF/sub 2/ slag system. The iso-activity diagram for RE/sub 2/O/sub 3/ and the liquid boundary for slags system were estimated

Photoluminescence of trivalent rare earths in perovskite stacking polytypes Ba/sub 2/Lasub(2-x)REsub(x)/sup 3 +/MgW/sub 2/vacantO/sub 12/, Ba/sub 6/Ysub(2-x)REsub(x)/sup 3 +/W/sub 3/vacantO/sub 18/, and Sr/sub 8/SrGdsub(2-x)REsub(x)/sup 3 +/W/sub 4/vacantO/sub 24/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1981-12-01

Rhombohedral 12 L staking polytypes Ba/sub 2/Lasub(2-x)REsub(x)/sup 3 +/MgW/sub 2/vacantO/sub 12/ show with RE/sup 3 +/ = Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm; the 18 L stacking polytypes Ba/sub 6/Ysub(2-x)REsub(x)/sup 3 +/W/sub 3/vacantO/sub 18/ and the polymorphic perovskites Sr/sub 8/SrGdsub(2-x)REsub(x)/sup 3 +/W/sub 4/vacantO/sub 24/ with RE/sup 3 +/ = Sm, Eu, Dy, Ho, Er visible photoluminescence. The concentration dependence and the influence of the coordination number of the rare earth are reported.

Parameterization of rotational spectra

International Nuclear Information System (INIS)

Zhou Chunmei; Liu Tong

1992-01-01

The rotational spectra of the strongly deformed nuclei with low rotational frequencies and weak band mixture are analyzed. The strongly deformed nuclei are commonly encountered in the rare-earth region (e. g., 150 220). A lot of rotational band knowledge are presented

Low-temperature SCR of NO with NH{sub 3} over activated semi-coke composite-supported rare earth oxides

Energy Technology Data Exchange (ETDEWEB)

Wang, Jinping; Yan, Zheng; Liu, Lili; Zhang, Yingyi; Zhang, Zuotai; Wang, Xidong, E-mail: xidong@pku.edu.cn

2014-08-01

The catalysts with different rare earth oxides (La, Ce, Pr and Nd) loaded onto activated semi-coke (ASC) via hydrothermal method are prepared for the selective catalytic reduction (SCR) of NO with NH{sub 3} at low temperature (150–300 °C). It is evidenced that CeO{sub 2} loaded catalysts present the best performance, and the optimum loading amount of CeO{sub 2} is about 10 wt%. Composite catalysts by doping La, Pr and Nd into CeO{sub 2} are prepared to obtain further improved catalytic properties. The SCR mechanism is investigated through various characterizations, including XRD, Raman, XPS and FT-IR, the results of which indicate that the oxygen defect plays an important role in SCR process and the doped rare earth elements effectively serve as promoters to increase the concentration of oxygen vacancies. It is also found that the oxygen vacancies in high concentration are favored for the adsorption of O{sub 2} and further oxidation of NO, which facilitates a rapid progressing of the following reduction reactions. The SCR process of NO with NH{sub 3} at low temperature over the catalysts of ASC composite-supported rare earth oxides mainly follows the Langmuir–Hinshlwood mechanism.

Unusual pressure dependence of the crystallographic structure in RNiO{sub 3} perovskites (R = rare earth)

Energy Technology Data Exchange (ETDEWEB)

Medarde, M.; Mesot, J.; Rosenkranz, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Lacorre, P. [Lab. Fluorures, Le Mans (France); Marshall, W.; Loveday, J.S. [Edinburgh Univ. (United Kingdom); Klotz, S.; Hamel, G. [Paris-6 Univ., 75 (France)

1997-09-01

We report the first experimental observation of a pressure-induced structural phase transition in the RNiO{sub 3} series (R = rare earth). At {approx_equal} 40 kbar, the space group of NdNiO{sub 3} changes from Pbnm(orthorhombic) to the PrNiO{sub 3} indicating that the symmetry of the structure increases with pressure. (author) 1 fig., 7 refs.

Determining the Ocean's Role on the Variable Gravity Field on Earth Rotation

Science.gov (United States)

Ponte, Rui M.

1999-01-01

A number of ocean models of different complexity have been used to study changes in the oceanic mass field and angular momentum and their relation to the variable Earth rotation and gravity field. Time scales examined range from seasonal to a few days. Results point to the importance of oceanic signals in driving polar motion, in particular the Chandler and annual wobbles. Results also show that oceanic signals have a measurable impact on length-of-day variations. Various circulation features and associated mass signals, including the North Pacific subtropical gyre, the equatorial currents, and the Antarctic Circumpolar Current play a significant role in oceanic angular momentum variability.

Probable Rotation States of Rocket Bodies in Low Earth Orbit

Science.gov (United States)

Ojakangas, Gregory W.; Anz-Meador, P.; Cowardin, H.

2012-01-01

In order for Active Debris Removal to be accomplished, it is critically important to understand the probable rotation states of orbiting, spent rocket bodies. As compared to the question of characterizing small unresolved debris, in this problem there are several advantages: (1) objects are of known size, mass, shape and color, (2) they have typically been in orbit for a known period of time, (3) they are large enough that resolved images may be obtainable for verification of predicted orientation, and (4) the dynamical problem is simplified to first order by largely cylindrical symmetry. It is also nearly certain for realistic rocket bodies that internal friction is appreciable in the case where residual liquid or, to a lesser degree, unconsolidated solid fuels exist. Equations of motion have been developed for this problem in which internal friction as well as torques due to solar radiation, magnetic induction, and gravitational gradient are included. In the case of pure cylindrical symmetry, the results are compared to analytical predictions patterned after the standard approach for analysis of symmetrical tops. This is possible because solar radiation and gravitational torques may be treated as conservative. Agreement between results of both methods ensures their mutual validity. For monotone symmetric cylinders, solar radiation torque vanishes if the center of mass resides at the geometric center of the object. Results indicate that in the absence of solar radiation effects, rotation states tend toward an equilibrium configuration in which rotation is about the axis of maximum inertia, with the axis of minimum inertia directed toward the center of the earth. Solar radiation torque introduces a modification to this orientation. The equilibrium state is asymptotically approached within a characteristic timescale given by a simple ratio of relevant characterizing parameters for the body in question. Light curves are simulated for the expected asymptotic final

The Use of Daily Geodetic UT1 and LOD Data in the Optimal Estimation of UT1 and LOD With the JPL Kalman Earth Orientation Filter

Science.gov (United States)

Freedman, A. P.; Steppe, J. A.

1995-01-01

The Jet Propulsion Laboratory Kalman Earth Orientation Filter (KEOF) uses several of the Earth rotation data sets available to generate optimally interpolated UT1 and LOD series to support spacecraft navigation. This paper compares use of various data sets within KEOF.

Daily intakes of alkaline earth metals in Japanese males

International Nuclear Information System (INIS)

Shiraishi, Kunio; Yamamoto, Masayoshi; Ueno, Kaoru

1994-01-01

Diet samples were collected for two duplicate portion studies and one market basket study. 226 Ra in the diet samples was determined by alpha spectrometry and daily intake was estimated as 23 mBq (0.62 pCi) per person. Other alkaline earth metals were determined by inductively coupled plasma atomic-emission spectrometry. Average mineral intakes of calcium, magnesium, strontium, and barium were 0.55 g, 0.21 g, 2.3 mg, and 0.39 mg, respectively. Element ratios magnesium:calcium 0.38, strontium:calcium 4.2 x 10 -3 barium:calcium 7.1 X 10 -4 , and Ra:calcium 1.1 x 10 -12 were found in the diet; these compared with element ratios in Japanese vertebrae of magnesium:calcium 0.011, strontium:calcium 3.1 x 10 -4 , barium:calcium 2.7 x 10 -5 , and radium:calcium 2.6 x 10 -14 . Observed ratios, defined as the element ratio in bone divided by the respective element intake ratio in Japanese males, were as follows: 226 Ra 0.02, magnesium 0.03, strontium 0.07, and barium 0.04

An Examination of the Change in the Earth's Rotation Rate From Ancient Chinese Observations of Lunar Occultations of the Planets

National Research Council Canada - National Science Library

Hilton, James L; Seidelmann, P. Kenneth; Ciyuan, Liu

1992-01-01

...., a period with no other known observations useful for Earth rotation studies. The observations are compared to topocentric ephemerides computed using Bretagnon's planetary theories VSOP82 and the Chapront-Touze lunar theory ELP2000-85...

Decrease of the atmospheric co-rotation with height

International Nuclear Information System (INIS)

Membrado, M; Pacheco, A F

2010-01-01

Considering our atmosphere as a steady viscous gaseous envelope that co-rotates with the Earth, we obtain a solution for the form in which this induced rotational effect decreases as a function of the distances to the centre of the Earth and to the rotation axis.

On the amplitude changes of seasonal components in the rate of rotation of the earth

International Nuclear Information System (INIS)

Okazaki, Seichi

1975-01-01

In this paper an analysis of seasonal variations in the rate of the Earth's rotation is carried out with regard to the amplitude changes particularly. It is found that the annual and semi-annual components have peculiar changes in the amplitude, i.e., (i) the annual term has been a tendency of the amplitude enhancement of about 0.10 ms day -1 and following decay which occurred rhythmically at 1957. 5, 1963. 5, and 1969. 5, with a 6-yr period and (ii) the semi-annual term had a step change of the amplitude by about +0.13 ms day -1 at the beginning of 1962. As for the amplitude change of the annual term with the repeating period of 6 yr, there is a close correlation between this amplitude change and the westerly zonal winds at the 500-mb level in the particular zone (35 0 -55 0 N). Concerning the periods before and after the amplitude enhancement, the difference of changes in the relative westerly angular momentum in this zone is conspicuous more than that in the zone (20 0 -35 0 N). The amplitude change of the semi-annual term is proved to be attributed to the difference in Δαsub(α) between the fundamental catalogs FK3 and FK4. (auth.)

Peculiarities of the thermal regime of the Russian plain depending on tidal oscillation Earth rotation speed

Science.gov (United States)

Akimov, L. M.

2018-01-01

Typification of fields of anomaly of temperature in the central part of East European Plain depending on the main phases of the Moon taking into account these tidal fluctuations of speed of rotation of Earth is presented. The main regularities of spatial distribution of anomaly of temperature in December are revealed. The opposite dependence of distribution of anomaly of temperature on antiphases of the Moon is established.

Surface passivation of Fe{sub 3}O{sub 4} nanoparticles with Al{sub 2}O{sub 3} via atomic layer deposition in a rotating fluidized bed reactor

Energy Technology Data Exchange (ETDEWEB)

Duan, Chen-Long; Deng, Zhang; Cao, Kun [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Yin, Hong-Feng [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Shan, Bin [State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

2016-07-15

Iron(II,III) oxide (Fe{sub 3}O{sub 4}) nanoparticles have shown great promise in many magnetic-related applications such as magnetic resonance imaging, hyperthermia treatment, and targeted drug delivery. Nevertheless, these nanoparticles are vulnerable to oxidation and magnetization loss under ambient conditions, and passivation is usually required for practical applications. In this work, a home-built rotating fluidized bed (RFB) atomic layer deposition (ALD) reactor was employed to form dense and uniform nanoscale Al{sub 2}O{sub 3} passivation layers on Fe{sub 3}O{sub 4} nanoparticles. The RFB reactor facilitated the precursor diffusion in the particle bed and intensified the dynamic dismantling of soft agglomerates, exposing every surface reactive site to precursor gases. With the aid of in situ mass spectroscopy, it was found that a thicker fluidization bed formed by larger amount of particles increased the residence time of precursors. The prolonged residence time allowed more thorough interactions between the particle surfaces and the precursor gas, resulting in an improvement of the precursor utilization from 78% to nearly 100%, even under a high precursor feeding rate. Uniform passivation layers around the magnetic cores were demonstrated by both transmission electron microscopy and the statistical analysis of Al mass concentrations. Individual particles were coated instead of the soft agglomerates, as was validated by the specific surface area analysis and particle size distribution. The results of thermogravimetric analysis suggested that 5 nm-thick ultrathin Al{sub 2}O{sub 3} coatings could effectively protect the Fe{sub 3}O{sub 4} nanoparticles from oxidation. The x-ray diffraction patterns also showed that the magnetic core crystallinity of such passivated nanoparticles could be well preserved under accelerated oxidation conditions. The precise thickness control via ALD maintained the saturation magnetization at 66.7 emu/g with a 5 nm-thick Al{sub

TOMS/Earth Probe UV Reflectivity Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe UV Reflectivity Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The shortname for this Level-3...

Studies on the Ln/sub 2/O/sub 3/ (Ln: rare-earth elements)-SrO-V/sub 2/O/sub 3/ system, 1. Phase diagrams at 1400/sup 0/C

Energy Technology Data Exchange (ETDEWEB)

Shin-ike, T [Osaka Dental Coll., Hirakata (Japan); Adachi, G; Shiokawa, J

1980-11-01

Rare-earth oxides Ln/sub 2/O/sub 3/ (Ln : Nd, Eu or Er), strontium oxide SrO and vanadium oxide V/sub 2/O/sub 3/ were mixed in a given molecular ratio, heated at 1400/sup 0/C in vacuum. The products were examined by an x-ray diffraction method to study the phase relations of the ternary systems. On heating, part of the trivalent vanadium was oxidized to the tetravalent state by atmospheric oxygen. In this experimental condition, the following ternary-phase solid solutions were identified: perovskite type Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.3. cubic, x < 0.3: orthorhombic) and Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.4: cubic, x < 0.4: orthorhombic), K/sub 2/NiF/sub 4/ type SrO.Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.3) and SrO.Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.4) and Eu/sub 3/Ti/sub 2/O/sub 7/ type SrO.2Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.3) and SrO.2Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) (x > 0.4). For the Er/sub 2/O/sub 3/-SrO-V/sub 2/O/sub 3/ system, only a mixture of Er/sub 2/O/sub 3/, SrVO sub(2.9), ErVO/sub 3/, SrO and V/sub 2/O/sub 3/ was obtained.

Nascent rotational distributions of N+2(X 2Σ+/sub g/) produced by electron-impact ionization of N2 in a supersonic beam

International Nuclear Information System (INIS)

Nagata, T.; Nakajima, A.; Kondow, T.; Kuchitsu, K.

1987-01-01

Laser-induced fluorescence from nascent N + 2 (X 2 Σ + /sub g/) ions produced by electron impact on a N 2 supersonic beam was observed. An analysis of the B 2 Σ + /sub u/-X 2 Σ + /sub g/ (0,0) band shows that the rotational state distributions cannot be represented by a single Boltzmann function, higher N'' levels being overpopulated. Experimental and analytical efforts were made to minimize the influence of cascading and relaxation on the rotational distributions. The rotational energy of N + 2 (X) thus estimated increases with decreasing electron energy from 2.26 +- 0.16 meV at 300 eV to 4.24 +- 0.27 meV at 25 eV. This trend is explained qualitatively in terms of angular momentum transfer through multipole electron--molecule interactions

Magneto-optically modulated CH/sub 3/OH laser For faraday rotation measurements in tokamaks

International Nuclear Information System (INIS)

Mansfield, D.K.; Johnson, L.C.

1981-01-01

Distortion-free intracavity polarization modulation of an optically pumped CH/sub 3/OH laser is shown to be viable. The possible use of this modulation technique to make a multichannel Faraday rotation measurement on a Tokamak device is discussed. In addition, the CdTe Faraday modulator employed in this study is shown to have an anomalously large Verdet constant. 12 refs

Angle-resolved photoemission spectroscopy of rare earth LaSb{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Michiardi, Matteo; Arnold, Fabian; Faerch Fisher, Karl Frederik; Svane, Axel; Bianchi, Marco; Brummerstedt Iversen, Bo; Hofmann, Philip [Aarhus University (Denmark); Shwetha, G.; Kanchana, V. [IIT-Hyderabad (India); Ganapathy, Vaitheeswaran [University of Hyderabad (India)

2016-07-01

Several rare earth diantimonides have been found to exhibit intriguing electronic properties such as anisotropic linear and non-saturating magnetoresistance. Among these materials, LaSb{sub 2} is not only considered for application in magnetoresistive devices but it is also found to be superconducting at low temperatures and it is investigated as candidate material to host charge density wave phases. Despite the several studies on its transport properties, the electronic structure of LaSb{sub 2} is still largely unknown. Here we present an angle-resolved photoemission spectroscopy and ab-initio calculation study of LaSb{sub 2}(001). The observed band structure is found to be in good agreement with theoretical predictions. Our results reveal that LaSb{sub 2} is a semimetal with a strongly nested two-dimensional Fermi surface. The low energy spectrum is characterized by four massive hole pockets and by four shallow, strongly directional, electron pockets that exhibit Dirac-like dispersion. We speculate on the possibility that this peculiar electronic structure drives the magnetoresistance to its quantum limit, explaining its unconventional behavior.

INTEGRATION OF THE ROTATION OF AN EARTH-LIKE BODY AS A PERTURBED SPHERICAL ROTOR

International Nuclear Information System (INIS)

Ferrer, Sebastian; Lara, Martin

2010-01-01

For rigid bodies close to a sphere, we propose an analytical solution that is free from elliptic integrals and functions, and can be fundamental for application to perturbed problems. After reordering the Hamiltonian as a perturbed spherical rotor, the Lie-series solution is generated up to an arbitrary order. Using the inertia parameters of different solar system bodies, the comparison of the approximate series solution with the exact analytical one shows that the precision reached with relatively low orders is at the same level of the observational accuracy for the Earth and Mars. Thus, for instance, the periodic errors of the mathematical solution are confined to the microarcsecond level with a simple second-order truncation for the Earth. On the contrary, higher orders are required for the mathematical solution to reach a precision at the expected level of accuracy of proposed new theories for the rotational dynamics of the Moon.

Optimization of L1{sub 0} FePt/Fe{sub 45}Co{sub 55} thin films for rare earth free permanent magnet applications

Energy Technology Data Exchange (ETDEWEB)

Giannopoulos, G., E-mail: g.giannopoulos@inn.demokritos.gr; Psycharis, V.; Niarchos, D. [INN, NCSR Demokritos, Athens 15310 (Greece); Reichel, L. [IFW Dresden, P.O. Box 270116, 01171 Dresden (Germany); TU Dresden, Institute for Materials Science, 01062 Dresden (Germany); Markou, A.; Panagiotopoulos, I. [Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110 (Greece); Damm, C.; Fähler, S. [IFW Dresden, P.O. Box 270116, 01171 Dresden (Germany); Khan, Imran; Hong, Jisang [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of)

2015-06-14

The magnetic properties of magnetron sputtered bilayers consisting of Fe{sub 45}Co{sub 55} ultrathin layers on top of L1{sub 0} FePt films epitaxially grown on MgO substrates are studied in view of their possible application as rare earth free permanent magnets. It is found that FePt layers induce a tetragonal distortion to the Fe-Co layers which leads to increased anisotropy. This allows to take advantage of the Fe-Co high magnetic moment with less significant loss of the coercivity compared to a typical hard/soft exchange spring system. A maximum energy product approaching 50 MGOe is obtained for a FePt(7 ML)/FeCo/(5 ML) sample. The results are in accordance with first-principles computational methods, which predict that even higher energy products are possible for micromagnetically optimized microstructures.

Effects of Majorana physics on the UHE ν{sub τ} flux traversing the Earth

Energy Technology Data Exchange (ETDEWEB)

Duarte, Lucia [Universidad de la Republica, Instituto de Fisica, Facultad de Ingenieria, Montevideo (Uruguay); Romero, Ismael; Zapata, Gabriel; Sampayo, Oscar A. [Universidad Nacional de Mar del Plata, Instituto de Investigaciones Fisicas de Mar del Plata (IFIMAR), CONICET, UNMDP, Departamento de Fisica, Mar del Plata (Argentina)

2017-02-15

We study the effects produced by sterile Majorana neutrinos on the ν{sub τ} flux traversing the Earth, considering the interaction between the Majorana neutrinos and the standard matter as modeled by an effective theory. The surviving tau-neutrino flux is calculated using transport equations including Majorana neutrino production and decay. We compare our results with the pure Standard Model interactions, computing the surviving flux for different values of the effective lagrangian couplings, considering the detected flux by IceCube for an operation time of 10 years, and Majorana neutrinos with mass m{sub N} ∝ m{sub τ}. (orig.)

Rotational seismology

Science.gov (United States)

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

Rare-earths influence in the thermoluminescent response of monoclinic ZrO{sub 2}; Influencia de tierras raras en la respuesta termoluminiscente de ZrO{sub 2} monoclinico

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Gonzalez M, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Vasquez L, M.J.; Rubio R, E. [Centro Universitario de Vinculacion, BUAP, 72000 Puebla (Mexico)

2005-07-01

Zirconium oxide (ZrO{sub 2}) with rare-earths (Nd, Dy, Eu and Y) as dopant were prepared by sol gel method and irradiated with gamma radiation. The thermoluminescent (TL) signal was studied as function of the impurities present for temperatures from 50 to 350 C. Pure ZrO{sub 2} produces a strong TL signal induced by gamma radiation, with a maximum located at 150 C, while ZrO{sub 2} doped with Nd, Dy and Y showed a TL signal with minor intensity, but with a maximum like to pure ZrO{sub 2}. However, when Eu is present as impurity the TL signal is much smaller than pure ZrO{sub 2}, with a maximum very enlarged. These results indicate that exits a strong influence of the rare-earths presents in the TL response and opens the possibility to control the TL signal in a wide range of dosages allowing to use these systems as a wide range dosimeter. Details of the thermoluminescent behavior of pure and doped ZrO{sub 2} will be discussed. (Author)

A proof of the cancellation of the redistribution tidal potential effects on the rotation of an elastic Earth model

Science.gov (United States)

Baenas, Tomás; Escapa, Alberto; Ferrándiz, Jose Manuel

2014-05-01

The gravitational action of the Moon and the Sun on the elastic Earth 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 effects on the Earth 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 Earth 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 Earth 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 Earth 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 Earth 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

Ocean angular momentum signals in a climate model and implications for Earth rotation

Science.gov (United States)

Ponte, R. M.; Rajamony, J.; Gregory, J. M.

2002-03-01

Estimates of ocean angular momentum (OAM) provide an integrated measure of variability in ocean circulation and mass fields and can be directly related to observed changes in Earth rotation. We use output from a climate model to calculate 240 years of 3-monthly OAM values (two equatorial terms L1 and L2, related to polar motion or wobble, and axial term L3, related to length of day variations) representing the period 1860-2100. Control and forced runs permit the study of the effects of natural and anthropogenically forced climate variability on OAM. All OAM components exhibit a clear annual cycle, with large decadal modulations in amplitude, and also longer period fluctuations, all associated with natural climate variability in the model. Anthropogenically induced signals, inferred from the differences between forced and control runs, include an upward trend in L3, related to inhomogeneous ocean warming and increases in the transport of the Antarctic Circumpolar Current, and a significantly weaker seasonal cycle in L2 in the second half of the record, related primarily to changes in seasonal bottom pressure variability in the Southern Ocean and North Pacific. Variability in mass fields is in general more important to OAM signals than changes in circulation at the seasonal and longer periods analyzed. Relation of OAM signals to changes in surface atmospheric forcing are discussed. The important role of the oceans as an excitation source for the annual, Chandler and Markowitz wobbles, is confirmed. Natural climate variability in OAM and related excitation is likely to measurably affect the Earth rotation, but anthropogenically induced effects are comparatively weak.

Impact of larger rare earth Pr{sup 3+} ions on the physical properties of chemically derived Pr{sub x}CoFe{sub 2−x}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pachpinde, A.M.; Langade, M.M. [Department of Chemistry, Jawahar Art Science and Commerce College Andur, Osmanabad, MS (India); Lohar, K.S.; Patange, S.M. [Materials Research Laboratory, Srikrishna Mahavidyalaya Gunjoti, Omerga, Osmanabad 413 613, MS (India); Shirsath, Sagar E., E-mail: shirsathsagar@hotmail.com [Spin Device Technology Center, Department of Information Engineering, Shinshu University, Nagano 380 8553 (Japan)

2014-01-31

Highlights: • Rare earth Pr{sup 3+} substituted CoFe{sub 2}O{sub 4}. • Sol–gel auto combustion synthesis. • XRD and IR spectra reveal the spinel structure. • Magnetization and coercivity increased with Pr{sup 3+} substitution. - Abstract: Rare earth Pr{sup 3+} ions with its larger ionic radii substituted CoFe{sub 2}O{sub 4} nanoparticles with x ranging from 0.0 to 0.1 were synthesized by sol–gel auto-combustion chemical method. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR) and vibrating sample magnetometer (VSM) were employed to characterize the physical properties of these ferrite nanoparticles. XRD pattern reveals the formation of cubic spinel ferrite with the signature of PrFeO{sub 3} phases for x ⩾ 0.05. SEM images show that the synthesized samples are in good homogeneity with uniformly distributed grain. The results of IR spectroscopy analysis indicated that the functional groups of cobalt spinel ferrite were formed during the sol–gel process. The cations distribution between the tetrahedral (A-site) and octahedral sites (B-site) has been estimated by XRD analysis. Room temperature magnetic measurement shows saturation magnetization and coercivity increased from 54.7 to 64.2 emu/g and 644 to 1013 Oe, respectively with the increasing Pr{sup 3+} substitution.

The first quinary rare earth thiophosphates. Cs{sub 5}Ln{sub 3}X{sub 3}(P{sub 2}S{sub 6}){sub 2}(PS{sub 4}) (Ln = La, Ce, X = Br, Cl) and the quasi-quaternary Cs{sub 10}Y{sub 4}Cl{sub 10}(P{sub 2}S{sub 6}){sub 3}

Energy Technology Data Exchange (ETDEWEB)

Schoop, Leslie Mareike; Eger, Roland; Nuss, Juergen; Pielnhofer, Florian [Max Planck Institute for Solid State Research, Stuttgart (Germany); Lotsch, Bettina Valeska [Max Planck Institute for Solid State Research, Stuttgart (Germany); Nanosystems Initiative Munich (NIM) and Center for Nanoscience, Muenchen (Germany)

2017-12-13

We report the first examples of quinary rare earth thiophosphates with a fully ordered cation and anion distribution, Cs{sub 5}Ln{sub 3}X{sub 3}(P{sub 2}S{sub 6}){sub 2}(PS{sub 4}), (Ln = La, Ce and X = Br, Cl) as well as the quasi-quaternary Cs{sub 10}Y{sub 4}Cl{sub 10}(P{sub 2}S{sub 6}){sub 3}. These four new compounds crystallize in three different, unknown structure types. The yellowish, transparent, brittle Cs{sub 5}Ce{sub 3}Br{sub 3}(P{sub 2}S{sub 6}){sub 2}(PS{sub 4}) crystallizes in the orthorhombic space group Pnma (no. 62) with a = 13.276(3), b = 14.891(3), c = 19.593(4) Aa, and V = 3873(1) Aa{sup 3} in a novel structure type. Colorless crystals of Cs{sub 5}La{sub 3}Br{sub 3}(P{sub 2}S{sub 6}){sub 2}(PS{sub 4}) and Cs{sub 5}La{sub 3}Cl{sub 3}(P{sub 2}S{sub 6}){sub 2}(PS{sub 4}) are isotypic and were obtained in the monoclinic space group P2{sub 1}/m (no. 11) with a = 9.715(2), b = 14.310(3), c = 13.685(3) Aa, β = 100.16(3) and V = 1873(1) Aa{sup 3} and a = 9.513(2), b = 14.182(3), c = 13.699(3) Aa, β = 99.39(3) and V = 1823(1) Aa{sup 3}, respectively. Both structures contain isolated hexathiohypodiphosphate(IV) [P{sub 2}S{sub 6}]{sup 4-} and thiophosphate [PS{sub 4}]{sup 3-} units that are arranged alternately in layers. Cs{sub 10}Y{sub 4}Cl{sub 10}(P{sub 2}S{sub 6}){sub 3} crystallizes in colorless transparent platelets in the orthorhombic space group Pnnm (no. 58) with a = 13.153(3), b = 28.964(6), c = 7.780(2) Aa, and V = 2964(1) Aa{sup 3}. The structure is composed of isolated [P{sub 4/2}S{sub 6}]{sup 4-} octahedra containing four half occupied P positions surrounded octahedrally by sulfur. We show with Raman scattering that this disordered thiophosphate anion shows a Raman spectrum that is distinct from spectra published for other literature-known thiophosphate anions. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Calculation of new snow densities from sub-daily automated snow measurements

Science.gov (United States)

Helfricht, Kay; Hartl, Lea; Koch, Roland; Marty, Christoph; Lehning, Michael; Olefs, Marc

2017-04-01

In mountain regions there is an increasing demand for high-quality analysis, nowcasting and short-range forecasts of the spatial distribution of snowfall. Operational services, such as for avalanche warning, road maintenance and hydrology, as well as hydropower companies and ski resorts need reliable information on the depth of new snow (HN) and the corresponding water equivalent (HNW). However, the ratio of HNW to HN can vary from 1:3 to 1:30 because of the high variability of new snow density with respect to meteorological conditions. In the past, attempts were made to calculate new snow densities from meteorological parameters mainly using daily values of temperature and wind. Further complex statistical relationships have been used to calculate new snow densities on hourly to sub-hourly time intervals to drive multi-layer snow cover models. However, only a few long-term in-situ measurements of new snow density exist for sub-daily time intervals. Settling processes within the new snow due to loading and metamorphism need to be considered when computing new snow density. As the effect of these processes is more pronounced for long time intervals, a high temporal resolution of measurements is desirable. Within the pluSnow project data of several automatic weather stations with simultaneous measurements of precipitation (pluviometers), snow water equivalent (SWE) using snow pillows and snow depth (HS) measurements using ultrasonic rangers were analysed. New snow densities were calculated for a set of data filtered on the basis of meteorological thresholds. The calculated new snow densities were compared to results from existing new snow density parameterizations. To account for effects of settling of the snow cover, a case study based on a multi-year data set using the snow cover model SNOWPACK at Weissfluhjoch was performed. Measured median values of hourly new snow densities at the different stations range from 54 to 83 kgm-3. This is considerably lower than a 1

2nd Workshop on Tidal Friction and the Earth's Rotation

CERN Document Server

Sündermann, Jürgen

1982-01-01

In the four years which elapsed between our first workshop on .Tidal Friction and the Earth's Rotation and the second, the proceedings of which are presented here, many of the disciplines involved made ad­ vances which we felt should be exchanged. We were encouraged by the good reception our first report met with. Of course, more insight often means more problems. Therefore, this volume contains new results and revisions of matters which previously appeared settled. We are certainly far from "final answers". For this reason, differing opinions on some issues are to be found in this book. Moreover, we have refrained from making mathematical symbols uniform to avoid the risk of errors and non-compatibility with the earlier work of an author. The two workshops have stimulated collaboration between participants working in various fields. The final versions of the contributions have already profited from these discussions. We are convinced that they will also influence further investigations. This advancement of ...

On disturbances in the atmosphere produced by solar heating and by earth rotation

International Nuclear Information System (INIS)

Somsikov, V.M.

1980-01-01

Using solar terminator as an example analyzed are the problems connected with generation of various disturbances in atmosphere resulted from solar heating and earth rotation. An equation for atmosphere pressure disturbance in the spherical system of coordinates is obtained. The Green function of this equation is found for isothermal atmosphere. A spectrum of space harmonics of disturbances is found and its diagram is presented. It is shown that disturbances of large and small scales can arize in atmosphere simultaneously. They can be refferred to acoustic, gravitational and tidal waves. It is noted that the obtained equation solution permits to obtain a full spectrum of atmosphere vibrations, conditioned by its solar heating

The Dopants and Doping Level Dependence of the Structure and Magnetic Properties of the Eu (BA<sub>1-xsub>LR_x)>2sub>Cu>3sub>O>7+δsub>

Energy Technology Data Exchange (ETDEWEB)

Lin, Yu [Iowa State Univ., Ames, IA (United States)

2002-12-31

Eu(Ba<sub>1-xsub>LR_x)>2sub>Cu>3sub>O>7+δsub> were systematically studied in order to understand how the valence of the rear earth elements, ionic sizes and magnetic moment affect the crystal structure and magnetic and electrical properties. Differential thermal analyses were carried out to check the phase purity, X-ray data were least-squares fitted to determine the lattice parameters, and DC-SQUID magnetometry was used to characterize the superconducting properties. These results showed that the crystallography is consistent with other EuLR123ss series, LR = La, Pr, Eu. The lattice parameters vary with the ionic radii of the rare earth ions. Unlike the uniform change in lattice parameter, the superconducting transition did not vary systematically with the ionic size of the dopants. Although the general trend was for T<sub>c> to decrease with decreasing ionic size of the dopant, for the same doping level, Pr was anomalous, depressing T<sub>c> faster. Although the exact mechanism is not clear, this result is consistent with the depression of T<sub>c> for Pr substitution for the rare earth in R123. The critical current J<sub>c> was determined using the Bean model from magnetization versus field measurements as a function of temperature and field. The effect of the dopants on J<sub>c> with the increasing of temperature or applied field was determined. For T < 77 K and small values of x, the value of J<sub>c> was increased over that of the x = 0 sample. In addition, the smaller the substituting atom, the higher the J<sub>c> becomes. For instance, at x = 0.025, Eu123 < EuLa.025 < EuPr.025 < EuNd.025 < EuEu.025. The enhancement of J<sub>c> disappears for x > 0.05 and T > 0.5T<sub>c>.

TOMS/Earth Probe Total Column Ozone Daily L3 Global 1x1.25 deg Lat/Lon Grid V008

Data.gov (United States)

National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe Total Column Ozone Daily L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The shortname for this...

Superconductivity in alkaline earth-substituted La2CuO/sub 4-y/

International Nuclear Information System (INIS)

Bednorz, J.G.; Mueller, K.A.; Takashige, M.

1987-01-01

La 2 CuO/sub 4-y/ ceramics containing a few percent of Ca 2+ , Sr 2+ , and Ba 2+ ions have been prepared. Resistivity and susceptibility measurements exhibit superconductive onsets (as in earlier Ba 2+ -containing samples). The onset temperature La 2 CuO/sub 4-y/ with Sr 2+ is higher and its superconductivity-induced diamagnetism larger than that found with Ba 2+ and Ca 2+ . This is proof that the electronic change resulting from alkaline earth-doping, rather than the size effect, is responsible for superconductivity. The ionic radius of Sr 2+ is close to that of La 3+ for which it presumably substitutes

Daily and Sub-daily Precipitation for the Former USSR

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a compilation of in situ daily and hourly meteorological observations for the former USSR initially obtained within the framework of several joint...

Rare earth-rich cadmium compounds RE{sub 10}TCd{sub 3} (RE = Y, Tb, Dy, Ho, Er, Tm, Lu; T = Rh, Pd, Ir, Pt) with an ordered Co{sub 2}Al{sub 5}-type structure

Energy Technology Data Exchange (ETDEWEB)

Block, Theresa; Klenner, Steffen; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

2018-04-01

Eighteen new rare earth-rich intermetallic phases RE{sub 10}TCd{sub 3} (RE = Y, Tb, Dy, Ho, Er, Tm, Lu; T = Rh, Pd, Ir, Pt) were obtained by induction melting of the elements in sealed niobium ampoules followed by annealing in muffle furnaces. All samples were characterized by X-ray powder diffraction. The structures of four representatives were refined from single-crystal X-ray diffractometer data: ordered Co{sub 2}Al{sub 5} type, P6{sub 3}/mmc, a = 951.2(1), c = 962.9(2) pm, wR = 0.0460, 595 F{sup 2} values, 20 parameters for Er{sub 10}RhCd{sub 3}; a = 945.17(4), c = 943.33(4), wR = 0.0395, 582 F{sup 2} values, 21 parameters for Lu{sub 9.89}PdCd{sub 3.11}; a = 964.16(6), c = 974.93(6) pm, wR = 0.0463, 614 F{sup 2} values, 21 parameters for Y{sub 10}Ir{sub 1.09}Cd{sub 2.91}; a = 955.33(3), c = 974.56(3) pm, wR = 0.0508, 607 F{sup 2} values, 22 refined parameters for Dy{sub 9.92}IrCd{sub 3.08}. Refinements of the occupancy parameters revealed small homogeneity ranges resulting from RE/Cd, respectively T/Cd mixing. The basic building units of the RE{sub 10}TCd{sub 3} phases are transition metal-centered RE{sub 6} trigonal prisms (TP) that are condensed with double-pairs of empty RE{sub 6} octahedra via common triangular faces. A second type of rods is formed by slightly distorted RE3 rate at Cd{sub 6}RE{sub 6} icosahedra which are condensed via Cd{sub 3} triangular faces. The shortest interatomic distances occur for RE-T, compatible with strong covalent bonding interactions. Temperature dependent magnetic susceptibility measurements were performed for RE{sub 10}RhCd{sub 3} (RE = Dy-Tm, Lu), RE{sub 10}IrCd{sub 3} (RE = Er, Tm, Lu) and RE{sub 10}PtCd{sub 3} (RE = Y, Lu). While Y{sub 10}PtCd{sub 3} and Lu{sub 10}TCd{sub 3} (T = Rh, Ir, Pt) show Pauli paramagnetic behavior, the compounds containing paramagnetic rare earth elements show Curie-Weiss behavior (the experimental magnetic moments indicate stable trivalent RE{sup 3+}) and magnetic ordering at low temperatures

KEPLER-21b: A 1.6 R{sub Earth} PLANET TRANSITING THE BRIGHT OSCILLATING F SUBGIANT STAR HD 179070

Energy Technology Data Exchange (ETDEWEB)

Howell, Steve B. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Rowe, Jason F.; Bryson, Stephen T. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Quinn, Samuel N. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Marcy, Geoffrey W.; Isaacson, Howard [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Ciardi, David R. [NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Chaplin, William J.; Elsworth, Yvonne [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Metcalfe, Travis S. [High Altitude Observatory and Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO 80307 (United States); Monteiro, Mario J. P. F. G. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Appourchaux, Thierry [Institut d' Astrophysique Spatiale, Universite Paris XI-CNRS (UMR8617), Batiment 121, 91405 Orsay Cedex (France); Basu, Sarbani [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Creevey, Orlagh L. [Departamento de Astrofisica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Gilliland, Ronald L. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Quirion, Pierre-Olivier [Canadian Space Agency, 6767 Boulevard de l' Aeroport, Saint-Hubert, QC, J3Y 8Y9 (Canada); Stello, Denis [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Kjeldsen, Hans; Christensen-Dalsgaard, Joergen [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Garcia, Rafael A. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot-IRFU/SAp, 91191 Gif-sur-Yvette Cedex (France); and others

2012-02-20

We present Kepler observations of the bright (V = 8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R{sub Earth} object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequency-power spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34 {+-} 0.06 M{sub Sun} and 1.86 {+-} 0.04 R{sub Sun }, respectively, as well as yielding an age of 2.84 {+-} 0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3{sigma}) that the transit event is caused by a 1.64 {+-} 0.04 R{sub Earth} exoplanet in a 2.785755 {+-} 0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of {approx}10 M{sub Earth} (2{sigma}). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.

Influence of toroidal rotation on resistive tearing modes in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Wang, S.; Ma, Z. W., E-mail: zwma@zju.edu.cn [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2015-12-15

Influence of toroidal equilibrium plasma rotation on m/n = 2/1 resistive tearing modes is studied numerically using a 3D toroidal MHD code (CLT). It is found that the toroidal rotation with or without shear can suppress the tearing instability and the Coriolis effect in the toroidal geometry plays a dominant role on the rotation induced stabilization. For a high viscosity plasma (τ{sub R}/τ{sub V} ≫ 1, where τ{sub R} and τ{sub V} represent resistive and viscous diffusion time, respectively), the effect of the rotation shear combined with the viscosity appears to be stabilizing. For a low viscosity plasmas (τ{sub R}/τ{sub V} ≪ 1), the rotation shear shows a destabilizing effect when the rotation is large.

Characteristics of sub-daily precipitation extremes in observed data and regional climate model simulations

Czech Academy of Sciences Publication Activity Database

Beranová, Romana; Kyselý, Jan; Hanel, M.

2018-01-01

Roč. 132, 1-2 (2018), s. 515-527 ISSN 0177-798X R&D Projects: GA ČR(CZ) GA14-18675S Institutional support: RVO:68378289 Keywords : sub-daily precipitation * regional climate models * extremes * Czech Republic Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 2.640, year: 2016 https://link.springer.com/article/10.1007/s00704-017-2102-0

CsSc{sub 3}F{sub 6}[SeO{sub 3}]{sub 2}. A new rare-earth metal(III) fluoride oxoselenate(IV) with sections of the ReO{sub 3}-type structure

Energy Technology Data Exchange (ETDEWEB)

Greiner, Stefan; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany)

2017-09-04

A new representative of rare-earth metal(III) fluoride oxoselenates(IV) derivatized with alkali metals could be synthesized via solid-state reactions. Colorless single crystals of CsSc{sub 3}F{sub 6}[SeO{sub 3}]{sub 2} were obtained through the reaction of Sc{sub 2}O{sub 3}, ScF{sub 3}, and SeO{sub 2} (molar ratio 1:1:3) with CsBr as reactant and fluxing agent. For this purpose, corundum crucibles embedded as liners into evacuated silica ampoules were applied as containers for these reactions at 700 C for seven days. The new quintenary compound crystallizes in the trigonal space group P3m1 with a = 565.34(4) and c = 1069.87(8) pm (c/a = 1.892) for Z = 1. The crystal structure of CsSc{sub 3}F{sub 6}[SeO{sub 3}]{sub 2} contains two crystallographically different Sc{sup 3+} cations. Each (Sc1){sup 3+} is surrounded by six fluoride anions as octahedron, while the octahedra about (Sc2){sup 3+} are formed by three fluoride anions and three oxygen atoms from three terminal [SeO{sub 3}]{sup 2-} anions. The [(Sc1)F{sub 6}]{sup 3-} octahedra link via common F{sup -} vertices to six fac-[(Sc2)F{sub 3}O{sub 3}]{sup 6-} octahedra forming {sup 2}{sub ∞}{[Sc_3F_6O_6]"9"-} layers parallel to (001). These layers are separated by oxygen-coordinated Cs{sup +} cations (C.N. = 12), arranging for the charge compensation, while Se{sup 4+} cations within the layers surrounded by three oxygen atoms as ψ{sup 1}-tetrahedral [SeO{sub 3}]{sup 2-} units complete the structure. EDX measurements confirmed the composition of the title compound and single-crystal Raman studies showed the typical vibrational modes of isolated [SeO{sub 3}]{sup 2-} anions with ideal C{sub 3v} symmetry. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Specific heat of rare earth cobaltates RCoO{sub 3} (R = La, Pr and Nd)

Energy Technology Data Exchange (ETDEWEB)

Thakur, Rasna, E-mail: rasnathakur@yahoo.com [Department of Physics, Barkatullah University, Bhopal 462026 (India); Srivastava, Archana [Department of Physics, Sri Sathya Sai College for Women, Bhopal 462024 (India); Thakur, Rajesh K.; Gaur, N.K. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

2012-03-05

Highlights: Black-Right-Pointing-Pointer We have reported the temperature dependence (5 K {<=} T {<=} 1000 K) of the lattice contribution to the specific heat of rhombohedral LaCoO{sub 3} and orthocobaltates RCoO{sub 3} (R = Pr and Nd). Black-Right-Pointing-Pointer The strong electron phonon interactions are present in these compounds and lattice distortions can affect them substantially. Black-Right-Pointing-Pointer Thus Rigid Ion Model (RIM) is used for the first time to study the cohesive and thermal properties of the cobaltates RCoO{sub 3} with rare earth cation (R = La, Pr and Nd). Black-Right-Pointing-Pointer The values of specific heat calculated by us have shown remarkably good agreement with corresponding experimental data. Black-Right-Pointing-Pointer In addition, the results on the temperature dependence of cohesive energy ({phi}), molecular force constant (f), Reststrahlen frequency ({upsilon}), Debye temperature ({theta}{sub D}) and Gruneisen parameter ({gamma}) are also reported. - Abstract: We have reported the temperature dependence (5 K {<=} T {<=} 1000 K) of the lattice contribution to the specific heat of rhombohedral LaCoO{sub 3} and orthocobaltates RCoO{sub 3} (R = Pr and Nd). The strong electron phonon interactions are present in these compounds and lattice distortions can affect them substantially. Thus Rigid Ion Model (RIM) is used for the first time to study the cohesive and thermal properties of the cobaltates RCoO{sub 3} with rare earth cation (R = La, Pr and Nd). The values of specific heat calculated by us have shown remarkably good agreement with corresponding experimental data. In addition, the results on the temperature dependence of cohesive energy ({phi}), molecular force constant (f), Reststrahlen frequency ({upsilon}), Debye temperature ({theta}{sub D}) and Gruneisen parameter ({gamma}) are also reported.

Effect of rare-earth composition on microstructure and pinning properties of Zr-doped (Gd, Y)Ba{sub 2}Cu{sub 3}O{subx} superconducting tapes.

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V.; Chen, Y.; Zhang, Y.; Guevara, A.; Shi, T.; Yao, Y.; Majkic, G.; Lei, C.; Galtsyan, E.; Miller, D. J. (Materials Science Division); (Univ. Houston); (SuperPower Inc.)

2012-01-01

The effect of changing Gd + Y content from 1.2 to 1.6 in the precursor of (Gd,Y)Ba{sub 2}Cu{sub 3}O{sub 7} superconducting thin film tapes made by metal organic chemical vapor deposition (MOCVD) at a constant Gd:Y ratio and a fixed Zr content of 7.5% has been studied. The influence of changing the Gd:Y ratio from Gd = 0 to Y= 0 in 0.2 mol steps at a constant Gd + Y content of 1.2 in the precursor has also been investigated at a fixed Zr content of 7.5%. The critical current of these films is found to vary significantly as a function of rare-earth content as well as a function of rare-earth type. Even for a fixed Zr content, it is found that the critical current in the orientation of magnetic field parallel to the a-b plane and that in the orientation of field perpendicular to the a-b plane can be systematically varied with changing Gd + Y content as well as with changing Gd:Y ratio. The nanoscale defect structures along the a-b plane and along the c-axis are found to be sensitive to these changes in rare-earth content and type.

Spin dependence of rotational damping by the rotational plane mapping method

Energy Technology Data Exchange (ETDEWEB)

Leoni, S; Bracco, A; Million, B [Milan Univ. (Italy). Ist. di Fisica; Herskind, B; Dossing, T; Rasmussen, P [Niels Bohr Inst., Copenhagen (Denmark); Bergstrom, M; Brockstedt, A; Carlsson, H; Ekstrom, P; Nordlund, A; Ryde, H [Lund Univ. (Sweden). Dept. of Physics; Ingebretsen, F; Tjom, P O [Oslo Univ. (Norway); Lonnroth, T [Aabo Akademi, Turku (Finland). Dept. of Physics

1992-08-01

In the study of deformed nuclei by gamma spectroscopy, the large quadrupole transition strength known from rotational bands at high excitation energy may be distributed over all final states of a given parity within an interval defined as the rotational damping width {Gamma}{sub rot} The method of rotational plane mapping extracts a value of {Gamma}{sub rot} from the width of valleys in certain planes in the grid plots of triple gamma coincidence data sets. The method was applied to a high spin triple data set on {sup 162,163}Tm taken with NORDBALL at the tandem accelerator of the Niels Bohr Institute, and formed in the reaction {sup 37}Cl + {sup 130}Te. The value {Gamma}{sub rot} = 85 keV was obtained. Generally, experimental values seem to be lower than theoretical predictions, although the only calculation made was for {sup 168}Yb. 6 refs., 3 figs.

Trends in characteristics of sub-daily heavy precipitation and rainfall erosivity in the Czech Republic

Czech Academy of Sciences Publication Activity Database

Hanel, M.; Pavlásková, A.; Kyselý, Jan

2016-01-01

Roč. 36, č. 4 (2016), s. 1833-1845 ISSN 0899-8418 R&D Projects: GA ČR(CZ) GA14-18675S Institutional support: RVO:68378289 Keywords : sub-daily precipitation * rainfall events * erosivity * extremes * climate variability * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.760, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/joc.4463/abstract

Modeling impacts of NH{sub 3} on uptake of H{sub 2}SO{sub 4} by charged nucleating nanoparticles in the Earth's atmosphere

Energy Technology Data Exchange (ETDEWEB)

Nadykto, A. B., E-mail: anadykto@gmail.com [Atmospheric Science Research Center, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203 (United States); Department of Applied Mathematics, Moscow State University of Technology “STANKIN”, Vadkovsky per. 1, Moscow 127055 (Russian Federation); Nazarenko, K. M.; Markov, P. N. [Department of Applied Mathematics, Moscow State University of Technology “STANKIN”, Vadkovsky per. 1, Moscow 127055 (Russian Federation); Yu, F. [Atmospheric Science Research Center, State University of New York at Albany, 251 Fuller Road, Albany, NY 12203 (United States)

2016-06-08

The understanding of the role of ammonia, a well-known stabilizer of binary sulfuric acid-water clusters, in the gas-to-nanoparticle conversion in the Earth atmosphere is critically important for the assessment of aerosol radiative forcing associated with the climate changes. The sulfuric acid H{sub 2}SO{sub 4} is present in the atmosphere in the form of the gas-phase hydrates (H{sub 2}SO{sub 4})(H{sub 2}O){sub n}, whose interaction with NH{sub 3} leads to the formation of more stable bisulfate clusters (NH{sub 3})(H{sub 2}SO{sub 4})(H{sub 2}O){sub n}. Although the impact of NH{sub 3} on the thermochemical stability of binary clusters nucleating homogeneously has been studied in some detail in the past, the effect of ammonia on other microphysical properties relevant to nucleation remains insufficiently well understood. In the present study, the effect of ammonia on the electrical dipole moment controlling the nucleation of airborne ions via the dipole-charge interaction has been investigated using the Density Functional Theory (DFT), ab initio MP2 and model chemistry G3 methods. The presence of ammonia in (H{sub 2}SO{sub 4})(H{sub 2}O){sub n} is found to lead to very large enhancement in the dipole moment, which exceeds 2.0-2.5 Debyes (∼60-80%), 3.7-5.0 Debyes (∼90-180%), 1.4-4.5 Debyes (∼50-150%) and 2.1-5.5 Debyes (∼60-700%) for n = 0, n = 1, n = 2 and n = 3, respectively. The implications of this include the significantly increased uptake of the sulfuric acid, the key atmospheric nucleation precursor, by airborne ions and neutrals (due to dipole-dipole interaction), enhanced nucleation rates and the elevated production of ultrafine particles, which cause adverse health impacts.

Development of a Torsional Seismometer for measuring the rotational oscillations of the Earth.

Science.gov (United States)

Madziwa-Nussino, T. G.; Cowsik, R.; Wagoner, K.

2008-12-01

The motivations for the development and characterization of instruments capable of recording the rotations associated with seismic activity and normal mode oscillations were detailed extensively at the 2006 Fall- meeting of the American Geophysical Union in 2006 and in a special workshop at USGS-Menlo Park in 2007. This paper describes the effort and progress we have made in building a new instrument to be used for such measurements. Our prototype has two basic subsystems; a torsional oscillator and an optical lever for angular measurements. The essential idea behind the design maybe briefly stated as follows: A mechanical torsional oscillator with a natural frequency significantly below the lowest normal mode frequencies will couple negligibly to the rotational motions of the earth, even though the housing of the oscillator is firmly fixed to the earth. A sensitive optical lever, fixed to the Earth, observing such a balance can therefore faithfully measure the rotational oscillations of the Earth. The challenges we face in this development are two-fold: (a) the development of a mechanical torsional oscillator with a low enough natural frequency ~10- 3Hz and the fabrication of an optical lever with an angular resolution better than ~10- 6rad·Hz-1/2; (b) to make the instrument robust and field-worthy for the study of near-field strong motions at frequencies higher than ~10-2Hz. The initial implemented design is as follows: the balance bob consists of a circular mirror of diameter ~ 40mm, with its normal in the horizontal plane. The mirror is mounted within an aluminum framework whose moment of inertia may be adjusted as required and also used for capacitive damping of unwanted torsional oscillations. The configuration has a mass of under 50g and a moment of inertia of ~150g·cm2 about the suspension axis. The suspension fiber is made of SS-304 alloy with a cross section of 7μm × 110μm and length ~5cm. The angular frequency of natural oscillations for this

Inner Core Rotation from Geomagnetic Westward Drift and a Stationary Spherical Vortex in Earth's Core

Science.gov (United States)

Voorhies, C. V.

1999-01-01

The idea that geomagnetic westward drift indicates convective leveling of the planetary momentum gradient within Earth's core is pursued in search of a differentially rotating mean state, upon which various oscillations and secular effects might be superimposed. The desired state conforms to roughly spherical boundary conditions, minimizes dissipative interference with convective cooling in the bulk of the core, yet may aide core cooling by depositing heat in the uppermost core and lower mantle. The variational calculus of stationary dissipation applied to a spherical vortex within the core yields an interesting differential rotation profile akin to spherical Couette flow bounded by thin Hartmann layers. Four boundary conditions are required. To concentrate shear induced dissipation near the core-mantle boundary, these are taken to be: (i) no-slip at the core-mantle interface; (ii) geomagnetically estimated bulk westward flow at the base of the core-mantle boundary layer; (iii) no-slip at the inner-outer core interface; and, to describe magnetic locking of the inner core to the deep outer core, (iv) hydrodynamically stress-free at the inner-outer core boundary. By boldly assuming the axial core angular momentum anomaly to be zero, the super-rotation of the inner core is calculated to be at most 1.5 degrees per year.

Fluorine-ion conductivity of different technological forms of solid electrolytes R{sub 1–y}M{sub y}F{sub 3–y} (LaF{sub 3} Type ) (M = Ca, Sr, Ba; R Are Rare Earth Elements)

Energy Technology Data Exchange (ETDEWEB)

Sorokin, N. I., E-mail: nsorokin1@yandex.ru; Sobolev, B. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2016-05-15

We have investigated the conductivity of some representatives of different technological forms of fluoride-conducting solid electrolytes R{sub 1–y}M{sub y}F{sub 3–y} (M = Ca, Sr, Ba; R are rare earth elements) with an LaF{sub 3} structure: single crystals, cold- and hot-pressing ceramics based on a charge prepared in different ways (mechanochemical synthesis, solid-phase synthesis, and fragmentation of single crystals), polycrystalline alloys, etc. It is shown (by impedance spectroscopy), that different technological forms of identical chemical composition (R, M, y) exhibit different electrical characteristics. The maximum conductivity is observed for the single-crystal form of R{sub 1–y}M{sub y}F{sub 3–y} tysonite phases, which provides (in contrast to other technological forms) the formation of true volume ion-conducting characteristics.

Frequency Analysis of Extreme Sub-Daily Precipitation under Stationary and Non-Stationary Conditions across Two Contrasting Hydroclimatic Environments

Science.gov (United States)

Demaria, E. M.; Goodrich, D. C.; Keefer, T.

2017-12-01

Observed sub-daily precipitation intensities from contrasting hydroclimatic environments in the USA are used to evaluate temporal trends and to develop Intensity-Duration Frequency (IDF) curves under stationary and nonstationary climatic conditions. Analyses are based on observations from two United States Department of Agriculture (USDA)-Agricultural Research Service (ARS) experimental watersheds located in a semi-arid and a temperate environment. We use an Annual Maximum Series (AMS) and a Partial Duration Series (PDS) approach to identify temporal trends in maximum intensities for durations ranging from 5- to 1440-minutes. A Bayesian approach with Monte Carlo techniques is used to incorporate the effect of non-stationary climatic assumptions in the IDF curves. The results show increasing trends in observed AMS sub-daily intensities in both watersheds whereas trends in the PDS observations are mostly positive in the semi-arid site and a mix of positive and negative in the temperate site. Stationary climate assumptions lead to much lower estimated sub-daily intensities than those under non-stationary assumptions with larger absolute differences found for shorter durations and smaller return periods. The risk of failure (R) of a hydraulic structure is increased for non-stationary effects over those of stationary effects, with absolute differences of 25% for a 100-year return period (T) and a project life (n) of 100 years. The study highlights the importance of considering non-stationarity, due to natural variability or to climate change, in storm design.

CdS films deposited by chemical bath under rotation

Energy Technology Data Exchange (ETDEWEB)

Oliva-Aviles, A.I., E-mail: aoliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico); Patino, R.; Oliva, A.I. [Centro de Investigacion y de Estudios Avanzados Unidad Merida, Departamento de Fisica Aplicada. A.P. 73-Cordemex, 97310 Merida, Yucatan (Mexico)

2010-08-01

Cadmium sulfide (CdS) films were deposited on rotating substrates by the chemical bath technique. The effects of the rotation speed on the morphological, optical, and structural properties of the films were discussed. A rotating substrate-holder was fabricated such that substrates can be taken out from the bath during the deposition. CdS films were deposited at different deposition times (10, 20, 30, 40 and 50 min) onto Corning glass substrates at different rotation velocities (150, 300, 450, and 600 rpm) during chemical deposition. The chemical bath was composed by CdCl{sub 2}, KOH, NH{sub 4}NO{sub 3} and CS(NH{sub 2}){sub 2} as chemical reagents and heated at 75 deg. C. The results show no critical effects on the band gap energy and the surface roughness of the CdS films when the rotation speed changes. However, a linear increase on the deposition rate with the rotation energy was observed, meanwhile the stoichiometry was strongly affected by the rotation speed, resulting a better 1:1 Cd/S ratio as speed increases. Rotation effects may be of interest in industrial production of CdTe/CdS solar cells.

The quaternary arsenide oxides Ce{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} and Pr{sub 9}Au{sub 5-x}As{sub 8}O{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Bartsch, Timo; Hoffmann, Rolf-Dieter; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie

2016-07-01

The quaternary gold arsenide oxides Ce{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} and Pr{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} were synthesized from the rare earth elements (RE), rare earth oxides, arsenic and gold powder at maximum annealing temperatures of 1173 K. The structures were refined from single crystal X-ray diffractometer data: Pnnm, a=1321.64(6) pm, b=4073.0(3), c=423.96(2), wR2=0.0842, 3106 F{sup 2} values, 160 variables for Ce{sub 9}Au{sub 4.91(4)}As{sub 8}O{sub 6} and Pnnm, a=1315.01(4), b=4052.87(8), c=420.68(1) pm, wR2=0.0865, 5313 F{sup 2} values, 160 variables for Pr{sub 9}Au{sub 4.75(1)}As{sub 8}O{sub 6}. They represent a new structure type and show a further extension of pnictide oxide crystal chemistry. A complex polyanionic gold arsenide network [Au{sub 5}As{sub 8}]{sup 15-} (with some disorder in the gold substructure) is charge compensated with polycationic strands of condensed edge-sharing O rate at RE{sub 4/4} and O rate at RE{sub 4/3} tetrahedra ([RE{sub 4}O{sub 3}]{sub 2}{sup 12+}) as well as RE{sup 3+} cations in cavities.

Rotational and radial velocities of 1.3-2.2 M {sub ☉} red giants in open clusters

Energy Technology Data Exchange (ETDEWEB)

Carlberg, Joleen K., E-mail: jcarlberg@dtm.ciw.edu [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States)

2014-06-01

This study presents the rotational distribution of red giant (RG) stars in 11 old to intermediate age open clusters. The masses of these stars are all above the Kraft break, so they lose negligible amounts of their birth angular momentum (AM) during the main-sequence (MS) evolution. However, they do span a mass range with quite different AM distributions imparted during formation, with the stars less massive than ∼1.6M {sub ☉} arriving on the MS with lower rotation rates than the more massive stars. The majority of RGs in this study are slow rotators across the entire red giant branch regardless of mass, supporting the picture that intermediate-mass stars rapidly spin down when they evolve off the MS and develop convection zones capable of driving a magnetic dynamo. Nevertheless, a small fraction of RGs in open clusters show some level of enhanced rotation, and faster rotators are as common in these clusters as in the field RG population. Most of these enhanced rotators appear to be red clump stars, which is also true of the underlying stellar sample, while others are clearly RGs that are above or below the clump. In addition to rotational velocities, the radial velocities (RVs) and membership probabilities of individual stars are also presented. Cluster heliocentric RVs for NGC 6005 and Pismis 18 are reported for the first time.

Magnetic field of the Earth

Science.gov (United States)

Popov, Aleksey

2013-04-01

The magnetic field of the Earth has global meaning for a life on the Earth. The world geophysical science explains: - occurrence of a magnetic field of the Earth it is transformation of kinetic energy of movements of the fused iron in the liquid core of Earth - into the magnetic energy; - the warming up of a kernel of the Earth occurs due to radioactive disintegration of elements, with excretion of thermal energy. The world science does not define the reasons: - drift of a magnetic dipole on 0,2 a year to the West; - drift of lithospheric slabs and continents. The author offers: an alternative variant existing in a world science the theories "Geodynamo" - it is the theory « the Magnetic field of the Earth », created on the basis of physical laws. Education of a magnetic field of the Earth occurs at moving the electric charge located in a liquid kernel, at rotation of the Earth. At calculation of a magnetic field is used law the Bio Savara for a ring electric current: dB = . Magnetic induction in a kernel of the Earth: B = 2,58 Gs. According to the law of electromagnetic induction the Faradey, rotation of a iron kernel of the Earth in magnetic field causes occurrence of an electric field Emf which moves electrons from the center of a kernel towards the mantle. So of arise the radial electric currents. The magnetic field amplifies the iron of mantle and a kernel of the Earth. As a result of action of a radial electric field the electrons will flow from the center of a kernel in a layer of an electric charge. The central part of a kernel represents the field with a positive electric charge, which creates inverse magnetic field Binv and Emfinv When ?mfinv = ?mf ; ?inv = B, there will be an inversion a magnetic field of the Earth. It is a fact: drift of a magnetic dipole of the Earth in the western direction approximately 0,2 longitude, into a year. Radial electric currents a actions with the basic magnetic field of a Earth - it turn a kernel. It coincides with laws

Effects of anisotropic turbulent thermal diffusion on spherical magnetoconvection in the Earth's core

Science.gov (United States)

Ivers, D. J.; Phillips, C. G.

2018-03-01

We re-consider the plate-like model of turbulence in the Earth's core, proposed by Braginsky and Meytlis (1990), and show that it is plausible for core parameters not only in polar regions but extends to mid- and low-latitudes where rotation and gravity are not parallel, except in a very thin equatorial layer. In this model the turbulence is highly anisotropic with preferred directions imposed by the Earth's rotation and the magnetic field. Current geodynamo computations effectively model sub-grid scale turbulence by using isotropic viscous and thermal diffusion values significantly greater than the molecular values of the Earth's core. We consider a local turbulent dynamo model for the Earth's core in which the mean magnetic field, velocity and temperature satisfy the Boussinesq induction, momentum and heat equations with an isotropic turbulent Ekman number and Roberts number. The anisotropy is modelled only in the thermal diffusion tensor with the Earth's rotation and magnetic field as preferred directions. Nonlocal organising effects of gravity and rotation (but not aspect ratio in the Earth's core) such as an inverse cascade and nonlocal transport are assumed to occur at longer length scales, which computations may accurately capture with sufficient resolution. To investigate the implications of this anisotropy for the proposed turbulent dynamo model we investigate the linear instability of turbulent magnetoconvection on length scales longer than the background turbulence in a rotating sphere with electrically insulating exterior for no-slip and isothermal boundary conditions. The equations are linearised about an axisymmetric basic state with a conductive temperature, azimuthal magnetic field and differential rotation. The basic state temperature is a function of the anisotropy and the spherical radius. Elsasser numbers in the range 1-20 and turbulent Roberts numbers 0.01-1 are considered for both equatorial symmetries of the magnetic basic state. It is found

EARTH’S ROTATIONAL DECELERATION: DETERMINATION OF TIDAL FRICTION INDEPENDENT OF TIMESCALES

International Nuclear Information System (INIS)

Deines, Steven D.; Williams, Carol A.

2016-01-01

This paper determines Earth's rotational deceleration without relying on atomic or ephemeris timescales. Earth's rotation defines the civil time standard called Universal Time (UT). Our previous paper did not examine tidal friction in depth when analyzing the timescale divergence between UT and International Atomic Time (TAI). We examine all available paleontological fossils and deposits for the direct measurements of Earth's past rotation rates, because that record includes all contributing effects. We examine paleontological reports that date Earth's rotation rate using corals, bivalves, brachiopods, rhythmites, and stromatolites. Contributions that vary Earth's moment of inertia, such as continental plate drifts, coastline changes, ice age formations, and viscous glacial rebounds, are superimposed with the secular deceleration. The average deceleration of Earth's rotation rate from all available fossil data is found to be (5.969 ± 1.762) × 10 −7 rad yr −2 . Our value is 99.8% of the total rotational deceleration determined by Christodoulidis et al., who used artificial satellite data, and our value is 96.6% of the expected tidal friction value obtained by Stephenson and Morrison. Taking the derivative of conserved angular momentum, the predicted lunar orbital deceleration caused by the average rotational deceleration corresponds closely to lunar models. When evaluating the significant time gaps between UT and TAI, Earth's rotational deceleration is a minor contributing factor. Also, the secular deceleration rate is necessary to correctly date ancient astronomical events. We strongly encourage that more ocean paleontological evidence be found to supplement the record to separate the many periodic variations embedded in these data

EARTH’S ROTATIONAL DECELERATION: DETERMINATION OF TIDAL FRICTION INDEPENDENT OF TIMESCALES

Energy Technology Data Exchange (ETDEWEB)

Deines, Steven D. [Donatech Corporation, Fairfield, IA 52556 (United States); Williams, Carol A., E-mail: steven.deines@gmail.com, E-mail: cw@math.usf.edu [Department of Mathematics and Statistics (Prof. emeritus), University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620 (United States)

2016-04-15

This paper determines Earth's rotational deceleration without relying on atomic or ephemeris timescales. Earth's rotation defines the civil time standard called Universal Time (UT). Our previous paper did not examine tidal friction in depth when analyzing the timescale divergence between UT and International Atomic Time (TAI). We examine all available paleontological fossils and deposits for the direct measurements of Earth's past rotation rates, because that record includes all contributing effects. We examine paleontological reports that date Earth's rotation rate using corals, bivalves, brachiopods, rhythmites, and stromatolites. Contributions that vary Earth's moment of inertia, such as continental plate drifts, coastline changes, ice age formations, and viscous glacial rebounds, are superimposed with the secular deceleration. The average deceleration of Earth's rotation rate from all available fossil data is found to be (5.969 ± 1.762) × 10{sup −7} rad yr{sup −2}. Our value is 99.8% of the total rotational deceleration determined by Christodoulidis et al., who used artificial satellite data, and our value is 96.6% of the expected tidal friction value obtained by Stephenson and Morrison. Taking the derivative of conserved angular momentum, the predicted lunar orbital deceleration caused by the average rotational deceleration corresponds closely to lunar models. When evaluating the significant time gaps between UT and TAI, Earth's rotational deceleration is a minor contributing factor. Also, the secular deceleration rate is necessary to correctly date ancient astronomical events. We strongly encourage that more ocean paleontological evidence be found to supplement the record to separate the many periodic variations embedded in these data.

Revised predictions of long-period ocean tidal effects on Earth's rotation rate

Science.gov (United States)

Dickman, S. R.; Nam, Young S.

1995-01-01

The rotational response of Earth 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 earth 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.

Ion heating due to rotation and collision in magnetized plasma

International Nuclear Information System (INIS)

Anderegg, F.; Stern, R.A.; Skiff, F.; Hammel, B.A.; Tran, M.Q.; Paris, P.J.; Kohler, P.

1986-01-01

The E x B rotation and associated collisional ion heating of noble-gas magnetized plasmas are investigated with high resolution by means of laser-induced fluorescence and electrical probes. Plasma rotation results from a radial potential gradient which can be controlled by biasing of the discharge electrodes. The time and space evolution of the potential, the rotation velocity v/sub t//sub h//sub e//sub t//sub a/, and the ion perpendicular temperature indicate that heating is due to the randomization of v/sub t//sub h//sub e//sub t//sub a/ by ion-neutral collisions, and leads to temperature increases as high as a factor of 50 over initial values

Wind and the earth rotation effects on the trajectories and performance of tactical and strategic missiles

International Nuclear Information System (INIS)

Muslim, G.A.; Ali, A.; Tariq, G.F.

1998-01-01

This paper deals with a mathematical model developed for carrying out trajectories and performance analysis of aerodynamic bodies in flight. The model caters for external wind and the earth rotation effects, and simulates three dimensional motion of the powered or un powered vehicles in space,. The resulting system of ordinary differential equations is solved by fourth order Runge Kutta method. The trajectory and performance parameters are computed by a computer Code AERO. The sensitivity analysis of the burnout conditions has also been carried out for the strategic missiles. (author)

Effect of Tb and Al substitution within the rare earth and cobalt sublattices on magnetothermal properties of Dy{sub 0.5}Ho{sub 0.5}Co{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Chzhan, V.B., E-mail: lemuriform@gmail.com [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119334 (Russian Federation); National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Tereshina, E.A. [Institute of Physics CAS, Prague 18221 (Czech Republic); Mikhailova, A.B. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119334 (Russian Federation); Politova, G.A. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119334 (Russian Federation); International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); Tereshina, I.S. [Baikov Institute of Metallurgy and Material Sciences, Russian Academy of Sciences, Moscow 119334 (Russian Federation); Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Kozlov, V.I. [Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Ćwik, J. [International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-421 (Poland); Nenkov, K. [IFW Dresden, P.O. Box 270116, 01171 Dresden (Germany); Alekseeva, O.A.; Filimonov, A.V. [Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251 (Russian Federation)

2017-06-15

Highlights: • Single-phase (Tb,Dy,Ho)(Co,Al){sub 2} alloys synthesized using high-purity metals. • Temperature dependence of lattice parameters measured in a wide temperature range. • Tb and Al substitution increase the Curie temperature in Dy{sub 0.5}Ho{sub 0.5}Co{sub 2.} • The MCE measured by direct and indirect methods. • Materials with ‘table-like’ MCE are found. - Abstract: The effect of Tb and Al substitution within the rare earth and cobalt sublattices on structural and magnetothermal properties of Dy{sub 0.5}Ho{sub 0.5}Co{sub 2} has been studied. Multicomponent Laves phase alloys Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 2−y}Al{sub y} (x = 0, 0.3, 0.4, 0.5; y = 0, 0.25) synthesized using high-purity metals have been studied using X-ray diffraction analysis, heat capacity and magnetocaloric measurements. Dy{sub 0.5}Ho{sub 0.5}Co{sub 2} has a first order phase transition at the Curie temperature T{sub C} ≈ 110 K. Both Tb and Al substitution leads to increase of the T{sub C}. The increasing Tb content leads to the decreases slightly the MCE and all the transitions near the Curie temperature are of the first order. As for the Al-containing compounds, MCE measurements show that the phase transition type changes from the first to the second-order. The advantage of Tb{sub x}(Dy{sub 0.5}Ho{sub 0.5}){sub 1−x}Co{sub 1.75}Al{sub 0.25} as compared with Al-free alloys is ‘table-like’ behavior of MCE.

Motion and magnetic field structure of the Earth's magnetic tail near 30 R/sub E/

International Nuclear Information System (INIS)

Bowling, S.B.

1975-01-01

The analysis of data taken by the NASA-GSFC magnetometer experiment on the Explorer 34 spacecraft has shown that the diurnal wobble of the geomagnetic dipole axis measurably influences the position of the magnetotail near 30 R/sub E/ (earth radii). Viewed in the solar-ecliptic coordinate system, the dipole wobble resolves into components of motion perpendicular and parallel to the earth-sun line. The perpendicular component exerts a torque on the magnetotail and causes the neutral sheet (the midplane of the magnetotail) to pivot about an axis approximately parallel to the solar-wind flow direction. The parallel component encourages the neutral sheet to move above and below the solar-magnetospheric equatorial plane with an amplitude of 1 R/sub E/, as if the neutral sheet were hinged at a geocentric distance of 5.25 R/sub E/. The motion of the neutral sheet is also characterized by a random flapping in the solar-ecliptic Z-direction at a velocity of 100 km/sec and an amplitude of +- 2 R/sub E/. Results suggest the existence of a layer of nearly uniform cross-tail electric current that is about 2.3 R/sub E/ thick and envelops the neutral sheet. The magnetic field, whose average geometry resembles a flattened and extended dipole, gradually reverses direction within this current layer. The field is perpendicular to the neutral sheet where it has a value of 2 γ (1γ = 10 -5 Gauss). The analysis does not suggest a strong dependence of the magnetic-field configuration on the geomagnetic index Kp, although the field may intermittently disrupt into localized and short-lived magnetic loops during periods of enhanced geomagnetic activity

Vestibular thresholds for yaw rotation about an earth-vertical axis as a function of frequency.

Science.gov (United States)

Grabherr, Luzia; Nicoucar, Keyvan; Mast, Fred W; Merfeld, Daniel M

2008-04-01

Perceptual direction detection thresholds for yaw rotation about an earth-vertical axis were measured at seven frequencies (0.05, 0.1, 0.2, 0.5, 1, 2, and 5 Hz) in seven subjects in the dark. Motion stimuli consisted of single cycles of sinusoidal acceleration and were generated by a motion platform. An adaptive two-alternative categorical forced-choice procedure was used. The subjects had to indicate by button presses whether they perceived yaw rotation to the left or to the right. Thresholds were measured using a 3-down, 1-up staircase paradigm. Mean yaw rotation velocity thresholds were 2.8 deg s(-1) for 0.05 Hz, 2.5 deg s(-1) for 0.1 Hz, 1.7 deg s(-1) for 0.2 Hz, 0.7 deg s(-1) for 0.5 Hz, 0.6 deg s(-1) for 1 Hz, 0.4 deg s(-1) for 2 Hz, and 0.6 deg s(-1) for 5 Hz. The results show that motion thresholds increase at 0.2 Hz and below and plateau at 0.5 Hz and above. Increasing velocity thresholds at lower frequencies qualitatively mimic the high-pass characteristics of the semicircular canals, since the increase at 0.2 Hz and below would be consistent with decreased gain/sensitivity observed in the VOR at lower frequencies. In fact, the measured dynamics are consistent with a high pass filter having a threshold plateau of 0.71 deg s(-1) and a cut-off frequency of 0.23 Hz, which corresponds to a time constant of approximately 0.70 s. These findings provide no evidence for an influence of velocity storage on perceptual yaw rotation thresholds.

Core Angular Momentum and the IERS Sub-Centers Activity for Monitoring Global Geophysical Fluids. Part 1; Core Angular Momentum and Earth Rotation

Science.gov (United States)

Song, Xia-Dong; Chao, Benjamin (Technical Monitor)

1999-01-01

The part of the grant was to use recordings of seismic waves travelling through the earth's core (PKP waves) to study the inner core rotation and constraints on possible density anomalies in the fluid core. The shapes and relative arrival times of such waves associated with a common source were used to reduce the uncertainties in source location and excitation and the effect of unknown mantle structure. The major effort of the project is to assemble historical seismograms with long observing base lines. We have found original paper records of SSI earthquakes at COL between 1951 and 1966 in a warehouse of the U.S. Geological Survey office in Golden, Colorado, extending the previous measurements at COL by Song and Richards [1996] further back 15 years. Also in Alaska, the University of Alaska, Fairbanks Geophysical Institute (UAFGI) has been operating the Alaskan Seismic Network with over 100 stations since the late 1960s. Virtually complete archives of seismograms are still available at UAFGI. Unfortunately, most of the archives are in microchip form (develocorders), for which the use of waveforms is impossible. Paper seismograms (helicorders) are available for a limited number of stations, and digital recordings of analog signals started around 1989. Of the paper records obtained, stations at Gilmore Dome (GLM, very close to COL), Yukon (FYU), McKinley (MCK), and Sheep Creek Mountain (SCM) have the most complete continuous recordings.

Physics of untied rotating space elevators

Science.gov (United States)

Knudsen, Steven; Golubović, Leonardo

2015-12-01

We explore fundamental aspects of the physics of a novel class of dynamical systems, Rotating Space Elevators (RSE) (L. Golubović, S. Knudsen, Europhys. Lett. 86, 34001 (2009) and S. Knudsen, L. Golubović, Eur. Phys. J. Plus 129, 242 (2014)). An RSE is a loopy string reaching deep into outer space. The floppy RSE loop executes a double rotating motion due to which the objects sliding along the RSE string (climbers) can be transported far away from the Earth's surface without using internal engines or propulsion. By extensive numerical simulations and analytic calculations, this study addresses an interesting and provocative question at the very heart of the RSE physics: What will happen if one unties the rotating space elevator from the Earth? We find that the untied RSE exhibits rich nonlinear dynamics. In particular, strikingly, we find that the untied RSE may still behave as if it were tied to the planet. Such a quasi-tied yet untied RSE remains close to the Earth and exhibits persistent shape and enduring double rotating motion. Moreover, the climbers sliding along such a quasi-tied RSE move in much the same way as they do along a tied RSE. Under some conditions however we find that the untied RSE may undergo an instability leading it to a dynamical state in which the RSE hops well above the Earth surface. By changing the untied RSE parameters, the maximum height reached during hopping may be made to diverge. Such an untied RSE unbinds from the Earth to infinity, i.e., to interplanetary space.

The temperature dependence studies of rare-earth (Dy.sup.3+./sup., Sm.sup.3+./sup., Eu.sup.3+./sup. and Tb.sup.3+./sup.) activated Gd.sub.3./sub.Ga.sub.3./sub.Al.sub.2./sub.O.sub.12./sub. garnet single crystals

Czech Academy of Sciences Publication Activity Database

Bartosiewicz, Karol; Babin, Vladimir; Beitlerová, Alena; Boháček, Pavel; Jurek, Karel; Nikl, Martin

2017-01-01

Roč. 189, Sep (2017), s. 126-139 ISSN 0022-2313 R&D Projects: GA ČR GA16-15569S EU Projects: European Commission(XE) 316906 - LUMINET Institutional support: RVO:68378271 Keywords : Gd3Ga3Al2O12 * rare earth dopants * energy transfer * thermal quenching * single crystal Sub ject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.686, year: 2016

Crystal growth and structure of KLnP/sub 4/O/sub 12/

International Nuclear Information System (INIS)

Guangyan, H.; Shuzhen, L.; Shuying, Y.; Mingyu, C.

1985-01-01

Potassium rare earth tetraphosphates KLnP/sub 4/O/sub 12/ are a kind of polyphosphates of rare earths with unique properties and structures. KNdP/sub 4/O/sub 12/ is a high-Nd-concentration laser material with a non-centrosymmetric space group P2, yielding linear and nonlinear optical properties. α-KErP/sub 4/O/sub 12/ might be used as a material for engineering device purpose. KTbP/sub 4/O/sub 12/ can emit strong green fluorescence, it might be a kind of a new crystal material for laser or luminescence. In order to search for new crystal materials and to study the correlations among the composition, structures and the properties of rare earth compounds, the crystal growth of KLnP/sub 4/O/sub 12/ and their structures are studied in this paper

Automated protocols for spaceborne sub-meter resolution "Big Data" products for Earth Science

Science.gov (United States)

Neigh, C. S. R.; Carroll, M.; Montesano, P.; Slayback, D. A.; Wooten, M.; Lyapustin, A.; Shean, D. E.; Alexandrov, O.; Macander, M. J.; Tucker, C. J.

2017-12-01

The volume of available remotely sensed data has grown exceeding Petabytes per year and the cost for data, storage systems and compute power have both dropped exponentially. This has opened the door for "Big Data" processing systems with high-end computing (HEC) such as the Google Earth Engine, NASA Earth Exchange (NEX), and NASA Center for Climate Simulation (NCCS). At the same time, commercial very high-resolution (VHR) satellites have grown into a constellation with global repeat coverage that can support existing NASA Earth observing missions with stereo and super-spectral capabilities. Through agreements with the National Geospatial-Intelligence Agency NASA-Goddard Space Flight Center is acquiring Petabytes of global sub-meter to 4 meter resolution imagery from WorldView-1,2,3 Quickbird-2, GeoEye-1 and IKONOS-2 satellites. These data are a valuable no-direct cost for the enhancement of Earth observation research that supports US government interests. We are currently developing automated protocols for generating VHR products to support NASA's Earth observing missions. These include two primary foci: 1) on demand VHR 1/2° ortho mosaics - process VHR to surface reflectance, orthorectify and co-register multi-temporal 2 m multispectral imagery compiled as user defined regional mosaics. This will provide an easy access dataset to investigate biodiversity, tree canopy closure, surface water fraction, and cropped area for smallholder agriculture; and 2) on demand VHR digital elevation models (DEMs) - process stereo VHR to extract VHR DEMs with the NASA Ames stereo pipeline. This will benefit Earth surface studies on the cryosphere (glacier mass balance, flow rates and snow depth), hydrology (lake/water body levels, landslides, subsidence) and biosphere (forest structure, canopy height/cover) among others. Recent examples of products used in NASA Earth Science projects will be provided. This HEC API could foster surmounting prior spatial-temporal limitations while

Room temperature photoinduced magnetism in [py.H]{sub 3}[FeCl{sub 4}]{sub 2}Cl

Energy Technology Data Exchange (ETDEWEB)

Baniasadi, F. [Physics Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Tehranchi, M.M., E-mail: teranchi@sbu.ac.ir [Physics Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Fathi, M.B. [Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of); Hamidi, S.M. [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Safari, N.; Amani, V. [Faculty of Chemistry, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

2015-11-15

Photoinduced magnetism in a homogeneous solution of [py.H]{sub 3}[FeCl{sub 4}]{sub 2}Cl is measured by Faraday rotation in visible light (λ∼450–750 nm) at room temperature. The physics of this phenomenon may be attributed to electronic transitions caused by absorption of light. X-ray diffraction and Debye function analysis are therefore applied to find the abundant unit of molecules dissolved in the solution which are being further utilized to investigate the electronic structure and molecular orbitals by means of hybrid density function theory (B3LYP). Faraday rotation is observed at certain wavelengths consistent with energy differences of HOMO-LUMO energy levels. Thus this work puts forward a new material with certain photomagnetic properties which may be used in fabrication of room temperature magneto-optical switches. - Highlights: • Photoinduced magnetism in (FeCl{sub 4}){sub 2}(py.H){sub 3}Cl is illustrated via Faraday rotation. • The abundant unit of molecule is characterized by Debye function analysis of XRD. • PIM in the molecule is attributed to the charge transfer between HOMO-LUMO.

Prediction of secular acceleration of axial rotation of Mars

Science.gov (United States)

Barkin, Yu. V.

2009-04-01

of daily rotation of the Earth essentially surpasses non-tidal acceleration (35 %) which as shown the author is caused by the directed redistribution of fluid masses of the Earth, in turn caused by polar drift of the centre of mass of the liquid core of the Earth to the north [1]. In case of Mars the opposite picture is expected. It is quite possible, as show the executed estimations, that tidal deceleration of axial rotation of Mars much less than its positive acceleration caused by global dynamics of shells (the core and mantle). And it means, that as against the Earth in axial rotation of Mars in the present epoch an acceleration, instead of deceleration of rotation should be observed. References [1] Barkin Yu.V. (2001) Explanation and prediction of the secular variations of the Earth rotation, geopotential, force of gravity and geocenter drift. Proceedings of International Conference «AstroKazan-2001». Astronomy and geodesy in new millennium (24-29 September 2001), Kazan State University: Publisher «DAS», pp. 73-79. [2] Barkin Yu.V. (2007) To an explanation of non-tidal acceleration of the Earth diurnal rotation and secular trend of its pole. Proceedings of IUGG XXIV General Assembly, Perugia, Italy 2007: Earth: Our Changing Planet (Perugia, Italy, July 2-13, 2007), (G) - IAG, GS003, p. 3799. www. iugg2007perugia.it. [3] Barkin Yu.V. (2007) Celestial geodynamics and solution of the fundamental problems of geodesy, gravimetry and geophysics. Proceedings of IUGG XXIV General Assembly, Perugia, Italy 2007: Earth: Our Changing Planet (Perugia, Italy, July 2-13, 2007), (S) - IASPEI, JSS011, p. 2149. www. iugg2007perugia.it. [4] Barkin Yu.V. (2002) Explanation of endogenous activity of planets and satellites and its cyclicity. Izvestia cekzii nauk o Zemle. Rus. Acad. of Nat. Sciences, Issue 9, December 2002, M.: VINITI, pp. 45-97. In Russian.

Three series of quaternary rare-earth transition-metal pnictides with CaAl{sub 2}Si{sub 2}-type structures: RECuZnAs{sub 2}, REAgZnP{sub 2}, and REAgZnAs{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Stoyko, Stanislav S.; Ramachandran, Krishna K.; Blanchard, Peter E.R. [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2 (Canada); Rosmus, Kimberly A.; Aitken, Jennifer A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Mar, Arthur, E-mail: arthur.mar@ualberta.ca [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2 (Canada)

2014-05-01

Three series of quaternary rare-earth transition-metal pnictides REMM′Pn{sub 2} (M=Cu, Ag; M′=Zn; Pn=P, As) have been prepared by reaction of the elements at 800 °C, with crystal growth promoted through the addition of iodine. The extent of RE substitution is broad in these series: RECuZnAs{sub 2} (RE=Y, La-Nd, Sm, Gd–Lu), REAgZnP{sub 2} (RE=La–Nd, Sm, Gd–Dy), and REAgZnAs{sub 2} (RE=La-Nd, Sm, Gd-Dy). Powder and single-crystal X-ray diffraction analysis revealed that they adopt the trigonal CaAl{sub 2}Si{sub 2}-type structure (space group P3{sup ¯}m1, Z=1), in which Cu or Ag atoms are disordered with Zn atoms over the unique tetrahedrally coordinated transition-metal site. Magnetic measurements indicated Curie–Weiss behavior for several members of the RECuZnAs{sub 2} and REAgZnP{sub 2} series. Core-line X-ray photoelectron spectra (XPS) collected on some RECuZnAs{sub 2} members corroborate the charge assignment deduced by the Zintl concept for these compounds, (RE{sup 3+})(M{sup 1+})(Zn{sup 2+})(Pn{sup 3−}){sub 2}. Optical diffuse reflectance spectra and valence band XPS spectra established that these compounds are small band-gap semiconductors (up to ∼0.8 eV in REAgZnP{sub 2}) or semimetals (RECuZnAs{sub 2}). Band structure calculations also support this electronic structure and indicate that the band gap can be narrowed through appropriate chemical substitution (RE=smaller atoms, M=Cu, and Pn=As). - Graphical abstract: Cu or Ag atoms are disordered with Zn atoms over the tetrahedral site within relatively rigid [M{sub 2}Pn{sub 2}] slabs in three series of quaternary pnictides adopting the CaAl{sub 2}Si{sub 2}-type structure. - Highlights: • Three series (comprising 25 compounds) of pnictides REMM'Pn{sub 2} were prepared. • Cu or Ag atoms are disordered with Zn atoms within relatively rigid [M{sub 2}Pn{sub 2}] slabs. • They are semimetals or small band-gap semiconductors. • RECuZnAs{sub 2} and REAgZnP{sub 2} are generally

N{sub 2}O and CH{sub 4} emissions from a fallow–wheat rotation with low N input in conservation and conventional tillage under a Mediterranean agroecosystem

Energy Technology Data Exchange (ETDEWEB)

Tellez-Rio, Angela, E-mail: angela.tellez@upm.es [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); García-Marco, Sonia [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Navas, Mariela; López-Solanilla, Emilia [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Centro de Biotecnología y Genómica de Plantas UPM-INIA. Dpto Biotecnología. E.T.S.I. Agrónomos. Technical University of Madrid. Campus Montegancedo, UPM. Autovía M-40, Salida 38 N, 36S. 28223 Pozuelo de Alarcón. Madrid (Spain); Tenorio, Jose Luis [Dpto. de Medio Ambiente, INIA. Ctra. de La Coruña km. 7.5, 28040 Madrid (Spain); Vallejo, Antonio [E.T.S.I. Agrónomos, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)

2015-03-01

Conservation agriculture that includes no tillage (NT) or minimum tillage (MT) and crop rotation is an effective practice to increase soil organic matter in Mediterranean semiarid agrosystems. But the impact of these agricultural practices on greenhouse gases (GHGs), such as nitrous oxide (N{sub 2}O) and methane (CH{sub 4}), is variable depending mainly on soil structure and short/long-term tillage. The main objective of this study was to assess the long-term effect of three tillage systems (NT, MT and conventional tillage (CT)) and land-covers (fallow/wheat) on the emissions of N{sub 2}O and CH{sub 4} in a low N input agricultural system during one year. This was achieved by measuring crop yields, soil mineral N and dissolved organic C contents, and fluxes of N{sub 2}O and CH{sub 4}. Total cumulative N{sub 2}O emissions were not significantly different (P > 0.05) among the tillage systems or between fallow and wheat. The only difference was produced in spring, when N{sub 2}O emissions were significantly higher (P < 0.05) in fallow than in wheat subplots, and NT reduced N{sub 2}O emissions (P < 0.05) compared with MT and CT. Taking into account the water filled pore space (WFPS), both nitrification and denitrification could have occurred during the experimental period. Denitrification capacity in March was similar in all tillage systems, in spite of the higher DOC content maintained in the topsoil of NT. This could be due to the similar denitrifier densities, targeted by nirK copy numbers at that time. Cumulative CH{sub 4} fluxes resulted in small net uptake for all treatments, and no significant differences were found among tillage systems or between fallow and wheat land-covers. These results suggest that under a coarse-textured soil in low N agricultural systems, the impact of tillage on GHG is very low and that the fallow cycle within a crop rotation is not a useful strategy to reduce GHG emissions. - Highlights: • Tillage systems and land-covers with low N

Snow load effect on earth's rotation and gravitational field, 1979-1985

Science.gov (United States)

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.

R<sub>5sub>T>4sub> compounds - unique multifunctional intermetallics for basic research and applications

Energy Technology Data Exchange (ETDEWEB)

Mudryk, Yaroslav

2016-10-01

The unique properties of the rare-earth elements and their alloys have brought them from relative obscurity to high profile use in common high-tech applications. The broad technological impact of these remarkable materials may have never been known by the general public if not for the supply concerns that placed the rare-earth materials on the front page of newspapers and magazines. Neodymium and dysprosium, two essential components of Nd<sub>2sub>Fe>14sub>B-based high-performance permanent magnets, have drawn much attention and have been deemed critical materials for many energy-related applications. Ironically, the notoriety of rare-earth elements and their alloys is the result of a global movement to reduce their use in industrial applications and, thus, ease concerns about their supply and ultimately to reduce their position in high-tech supply chains. Research into the applications of lanthanide alloys has been de-emphasized recently due to the perception that industry is moving away from the use of rare-earth elements in new products. While lanthanide supply challenges justify efforts to diversify the supply chain, a strategy to completely replace the materials overlooks the reasons rare earths became important in the first place -- their unique properties are too beneficial to ignore. Rare-earth alloys and compounds possess truly exciting potential for basic science exploration and application development such as solid-state caloric cooling. In this brief review, we touch upon several promising systems containing lanthanide elements that show important and interesting magnetism-related phenomena.

Crystal structure, magnetization, {sup 125}Te NMR, and Seebeck coefficient of Ge{sub 49}Te{sub 50}R{sub 1} (R = La, Pr, Gd, Dy, and Yb)

Energy Technology Data Exchange (ETDEWEB)

Levin, E.M., E-mail: levin@iastate.edu [Division of Materials Sciences and Engineering, US Department of Energy Ames Laboratory, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Cooling, C. [Division of Materials Sciences and Engineering, US Department of Energy Ames Laboratory, Ames, IA 50011 (United States); Bud’ko, S.L. [Division of Materials Sciences and Engineering, US Department of Energy Ames Laboratory, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Straszheim, W.E. [Division of Materials Sciences and Engineering, US Department of Energy Ames Laboratory, Ames, IA 50011 (United States); Lograsso, T.A. [Division of Materials Sciences and Engineering, US Department of Energy Ames Laboratory, Ames, IA 50011 (United States); Department of Materials Sciences and Engineering, Iowa State University, Ames, IA 50011 (United States)

2017-05-01

GeTe, a self-doping semiconductor, is a well-known base compound for thermoelectric and phase-change materials. It is known, that replacement of Ge in Ag{sub 6.5}Sb{sub 6.5}Ge{sub 37}Te{sub 50} (TAGS-85) material by rare earth Dy significantly enhances both the power factor and thermoelectric figure of merit. Here we demonstrate how replacement of Ge in GeTe by rare earths with different atomic size and localized magnetic moments affect XRD patterns, magnetization, {sup 125}Te NMR spectra and spin-lattice relaxation, and the Seebeck coefficient of the alloys with a nominal composition of Ge{sub 49}Te{sub 50}R{sub 1} (R = La, Pr, Gd, Dy, and Yb). SEM, EDS and WDS data show that rare earth atoms in the matrix are present at smaller extent compared to a nominal composition, whereas rare earth also is present in inclusions. Rare earths affect the Seebeck coefficient, which is a result of interplay between the reduction due to higher carrier concentration and enhancement due to magnetic contribution. The effect of replacement of Ge in GeTe by Dy on the Seebeck coefficient is smaller than that observed in Ag{sub 6.5}Sb{sub 6.5}Ge{sub 36} Te{sub 50}Dy{sub 1}. This can be explained by larger amount of rare earth, which can be embedded into the lattice of materials containing [Ag + Sb] atomic pairs and possible effect from these pairs. - Highlights: • The effects of rare earth in Ge{sub 49}Te{sub 50}R{sub 1} (R = La, Pr, Gd, Dy, and Yb) are studied. • Rare earth atoms in the matrix are present at smaller extent compared to a nominal composition. • The effect on the Seebeck coefficient is a result from carrier concentration and magnetic contribution.

Exploration of R<sub>2sub>XM>2sub> (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge): Structural Motifs, the novel Compound Gd<sub>2sub>AlGe>2sub> and Analysis of the U<sub>3sub>Si>2sub> and Zr<sub>3sub>Al>2 sub>Structure Types

Energy Technology Data Exchange (ETDEWEB)

McWhorter, Sean William [Iowa State Univ., Ames, IA (United States)

2006-01-01

In the process of exploring and understanding the influence of crystal structure on the system of compounds with the composition Gd<sub>5sub>(Si_xGe>1-xsub>)>4sub> several new compounds were synthesized with different crystal structures, but similar structural features. In Gd<sub>5sub>(Si_xGe>1-xsub>)>4sub>, the main feature of interest is the magnetocaloric effect (MCE), which allows the material to be useful in magnetic refrigeration applications. The MCE is based on the magnetic interactions of the Gd atoms in the crystal structure, which varies with x (the amount of Si in the compound). The crystal structure of Gd<sub>5sub>(Si_xGe>1-xsub>)>4sub> can be thought of as being formed from two 3²434 nets of Gd atoms, with additional Gd atoms in the cubic voids and Si/Ge atoms in the trigonal prismatic voids. Attempts were made to substitute nonmagnetic atoms for magnetic Gd using In, Mg and Al. Gd<sub>2sub>MgGe>2sub> and Gd<sub>2sub>InGe>2sub> both possess the same 3²434 nets of Gd atoms as Gd<sub>5sub>(Si_xGe>1-xsub>)>4sub>, but these nets are connected differently, forming the Mo<sub>2sub>FeB>2sub> crystal structure. A search of the literature revealed that compounds with the composition R<sub>2sub>XM>2sub> (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge) crystallize in one of four crystal structures: the Mo<sub>2sub>FeB>2sub>, Zr<sub>3sub>Al>2sub>, Mn<sub>2sub>AlB>2sub> and W<sub>2sub>CoB>2sub> crystal structures. These crystal structures are described, and the relationships between them are highlighted. Gd<sub>2sub>AlGe>2sub> forms an entirely new crystal structure, and the details of its synthesis and characterization are given. Electronic structure calculations are performed to understand the nature of bonding in this compound and how

Rare earth chalcogels NaLnSnS{sub 4} (Ln = Y, Gd, Tb) for selective adsorption of volatile hydrocarbons and gases

Energy Technology Data Exchange (ETDEWEB)

Edhaim, Fatimah; Rothenberger, Alexander [Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

2017-08-16

The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS{sub 4}, NaGdSnS{sub 4}, and NaTbSnS{sub 4} is reported. Rare earth metal ions like Y{sup 3+}, Gd{sup 3+}, and Tb{sup 3+} react with the chalcogenide clusters [SnS{sub 4}]{sup 4-} in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m{sup 2}.g{sup -1} (NaYSnS{sub 4}), 479 m{sup 2}.g{sup -1} (NaGdSnS{sub 4}), and 354 m{sup 2}.g{sup -1} (NaTbSnS{sub 4}). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2-50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO{sub 2} over CH{sub 4} or H{sub 2}. The notable adsorption capacity for toluene (NaYSnS{sub 4}: 1108 mg.g{sup -1}; NaGdSnS{sub 4}: 921 mg.g{sup -1}; and NaTbSnS4: 645 mg.g{sup -1}) and high selectivity for gases (CO{sub 2}/H{sub 2}: 172 and CO{sub 2}/CH{sub 4}: 50 for NaYSnS{sub 4}, CO{sub 2}/H{sub 2}: 155 and CO{sub 2}/CH{sub 4}: 37 for NaGdSnS{sub 4}, and CO{sub 2}/H{sub 2}: 75 and CO{sub 2}/CH{sub 4}: 28 for NaTbSnS{sub 4}) indicate potential future use of chalcogels in adsorption-based gas or hydrocarbon separation processes. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The Earth is Flat, and I Can Prove It!

Science.gov (United States)

Klinger, Art

1998-01-01

Describes an educational program that asks students to attempt to prove that the earth is spherical and that it rotates. Presents tips to pique student interest and charts related to sensing the spin, nonrotation notions, flat earth fallacies, evidence that the earth is spherical and rotates, and the role of watersheds in proving that the earth…

Breathing mode distortion and magnetic order in rare-earth nickelates RNiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Hampel, Alexander; Ederer, Claude [Materials Theory, ETH Zuerich (Switzerland)

2016-07-01

Rare-earth nickelate perovskites display a rich and not yet fully understood phase diagram, where all RNiO{sub 3} compounds with R from Sm to Lu undergo a non-magnetic metal-insulator transition (MIT). This transition is connected to a lattice distortion, which can be described as breathing mode of the oxygen octahedra surrounding the Ni cations. Between 100-250 K the RNiO{sub 3} compounds undergo a magnetic transition to an antiferromagnetic (AFM) state, with a wave-vector k= [(1)/(4) (1)/(4) (1)/(4)] relative to the underlying simple cubic perovskite structure. Here, we use density functional theory and its extensions (DFT+U, DFT+DMFT) together with distortion mode analysis to explore the interplay between lattice distortions, magnetic order, and the strength of the local Coulomb interaction U in rare earth nickelates. Our results show a strong dependency of the breathing mode amplitude on the magnetic order, with a much larger breathing mode obtained for the AFM state compared to the ferromagnetic case. Furthermore, we demonstrate that DFT+U is able to capture the correct trends of the lattice distortions across the nickelate series.

Development of Sub-Daily Intensity Duration Frequency (IDF) Curves for Major Urban Areas in India

Science.gov (United States)

Ali, H.; Mishra, V.

2014-12-01

Extreme precipitation events disrupt urban transportation and cause enormous damage to infrastructure. Urban areas are fast responding catchments due to significant impervious surface. Stormwater designs based on daily rainfall data provide inadequate information. We, therefore, develop intensity-duration-frequency curves using sub-daily (1 hour to 12 hour) rainfall data for 57 major urban areas in India. While rain gage stations data from urban areas are most suitable, but stations are unevenly distributed and their data have gaps and inconsistencies. Therefore, we used hourly rainfall data from the Modern Era Retrospective-analysis for Research and Applications (MERRA), which provides a long term data (1979 onwards). Since reanalysis products have uncertainty associated with them we need to enhance their accuracy before their application. We compared daily rain gage station data obtained from Global Surface Summary of Day Data (GSOD) available for 65 stations for the period of 2000-2010 with gridded daily rainfall data provided by Indian Meteorological Department (IMD). 3-hourly data from NOAA/Climate Prediction Center morphing technique (CMORPH), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), and the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) were aggregated to daily for comparison with GSOD station data . TMPA is found to be best correlated with GSOD data. We used TMPA data to correct MERRA's hourly precipitation, which were applied to develop IDF curves. We compared results with IDF curves from empirical methods and found substantial disparities in the existing stormwater designs in India.

Rotational modes of a simple Earth model

Science.gov (United States)

Seyed-Mahmoud, B.; Rochester, M. G.; Rogister, Y. J. G.

2017-12-01

We study the tilt-over mode (TOM), the spin-over mode (SOM), the free core nutation (FCN), and their relationships to each other using a simple Earth model with a homogeneous and incompressible liquid core and a rigid mantle. Analytical solutions for the periods of these modes as well as that of the Chandler wobble is found for the Earth model. We show that the FCN is the same mode as the SOM of a wobbling Earth. The reduced pressure, in terms of which the vector momentum equation is known to reduce to a scalar second order differential equation (the so called Poincaŕe equation), is used as the independent variable. Analytical solutions are then found for the displacement eigenfucntions in a meridional plane of the liquid core for the aforementioned modes. We show that the magnitude of motion in the mantle during the FCN is comparable to that in the liquid core, hence very small. The displacement eigenfunctions for these aforementioned modes as well as those for the free inner core nutation (FICN), computed numerically, are also given for a three layer Earth model which also includes a rigid but capable of wobbling inner core. We will discuss the slow convergence of the period of the FICN in terms of the characteristic surfaces of the Poincare equation.

NIR-driven Moist Upper Atmospheres of Synchronously Rotating Temperate Terrestrial Exoplanets

Energy Technology Data Exchange (ETDEWEB)

Fujii, Yuka; Del Genio, Anthony D.; Amundsen, David S. [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY (United States)

2017-10-20

H{sub 2}O is a key molecule in characterizing atmospheres of temperate terrestrial planets, and observations of transmission spectra are expected to play a primary role in detecting its signatures in the near future. The detectability of H{sub 2}O absorption features in transmission spectra depends on the abundance of water vapor in the upper part of the atmosphere. We study the three-dimensional distribution of atmospheric H{sub 2}O for synchronously rotating Earth-sized aquaplanets using the general circulation model (GCM) ROCKE-3D, and examine the effects of total incident flux and stellar spectral type. We observe a more gentle increase of the water vapor mixing ratio in response to increased incident flux than one-dimensional models suggest, in qualitative agreement with the climate-stabilizing effect of clouds around the substellar point previously observed in GCMs applied to synchronously rotating planets. However, the water vapor mixing ratio in the upper atmosphere starts to increase while the surface temperature is still moderate. This is explained by the circulation in the upper atmosphere being driven by the radiative heating due to absorption by water vapor and cloud particles, causing efficient vertical transport of water vapor. Consistently, the water vapor mixing ratio is found to be well-correlated with the near-infrared portion of the incident flux. We also simulate transmission spectra based on the GCM outputs, and show that for the more highly irradiated planets, the H{sub 2}O signatures may be strengthened by a factor of a few, loosening the observational demands for a H{sub 2}O detection.

In vivo measurements of daily UV exposure of human anterior teeth using CaF{sub 2}:Tb,Sm as a thermoluminescence dosimeter

Energy Technology Data Exchange (ETDEWEB)

Saito, W., E-mail: saito-wataru@tsurumi-u.ac.j [Department of Operative Dentistry, Tsurumi University, School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama (Japan); Ikejima, I. [Department of Operative Dentistry, Tsurumi University, School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama (Japan); Fukuda, Y. [Department of Urban Environment, Faculty of Human Environment, Osaka Sangyo University, 3-1-1, Nakagaito, Daito, Osaka (Japan); Momoi, Y. [Department of Operative Dentistry, Tsurumi University, School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama (Japan)

2011-03-15

Ultraviolet radiation (UV) has been indicated as one of the causes of discoloration of dental materials yet the standard requires that dental polymers be irradiated with light from a xenon lamp, which includes UV, to evaluate their color stability. It is doubtful that dental polymers in the mouth are exposed to large energy of UV on a daily basis, but there have been no reports concerning exposure. In the present study, we used thermoluminescence (TL) from sintered CaF{sub 2}:Tb,Sm, which is highly sensitive to UV, to measure the daily energy of UV exposure to the labial surface of the maxillary anterior teeth, which are regarded as receiving the maximum exposure among oral tissues. We produced disks of CaF{sub 2} co-doped with Tb{sub 4}O{sub 7} and Sm{sub 2}O{sub 3} (sintered CaF{sub 2}:Tb,Sm) that were 5 mm in diameter and 1 mm thick, and placed them inside glass cases that had a 7-mm external diameter, 3-mm height, and 1-mm thickness of glass made of synthetic silica with {>=}90% UV transmittance. These glass cases were fixed in dental mouthpieces in a position corresponding to the central maxillary incisors. These mouthpieces were worn by 11 subjects and UV measurements were carried out over a 24-h period in a uniform environment. The results of these TL measurements showed a TL glow peak in the region of 430 K. This was the same as that seen with irradiation from a xenon lamp as basic illumination. The daily UV radiant energy was 72.2 mJ/cm{sup 2} (32.7-143.8 mJ/cm{sup 2}), calculated from the relationship between TL intensity and UV radiant energy. This corresponded to 0.02% of the UV radiant energy contained in the light irradiation specified by ISO 4049.

Magnetic properties of compounds Ba/sub 3/Fesub(2-x)Msub(x)UO/sub 9/ with M=Y, Sc, In and rare earth

Energy Technology Data Exchange (ETDEWEB)

Grenet, J C; Berthon, J [Paris-11 Univ., 91 - Orsay (France); Poix, P [Ecole Nationale Superieure de Chimie, 67 - Strasbourg (France)

1979-01-01

The compounds Ba/sub 3/Fesub(2-x)Msub(x)UO/sub 9/ crystallize in the perovskite type system. The magnetic behavior of these compounds is different when M/sup 3 +/ is dia- or paramagnetic. When M/sup 3 +/ is diamagnetic, the magnetic exchange interaction between A and B sublattices is strongly antiferromagnetic, the (UO/sub 6/)/sup 6 -/ clusters having a special effect. When M/sup 3 +/ is paramagnetic, the perovskite compounds have three magnetic sublattices. In the third one are placed rare earth ions M/sup 3 +/; in this case the A-B exchange interactions are antiferromagnetic but the interactions with the third sublattice are probably slightly ferromagnetic. This special feature and the fact that a temperature of compensation is missing differentiate these perovskites from the garnets.

The influence of molecular rotation on vibration--translation energy transfer

International Nuclear Information System (INIS)

McKenzie, R.L.

1977-01-01

The role of molecular rotations in the exchange of vibrational and translational energy is investigated for collisions between anharmonic diatomic molecules and structureless atoms. A three-dimensional, semiclassical, impact parameter description is applied with emphasis directed towards the influence of rotational coupling on the net rate of vibrational energy transfer summed over all final rotational states. These results are then related to the predictions of an equivalent collinear collision model, and their comparison allows an evaluation of the collinear approximation. The mechanisms of vibrational energy transfer including rotational transitions are shown to be separable into three classes, with the molecules belonging to each class identified first and foremost by their ratio of fundamental vibrational and rotational frequencies, ω/sub e//B/sub e/, and second by the proximity of their initial state to a near-resonant vibration--rotation transition with a small change in angular momentum. While the dynamics of molecules with ω/sub e//B/sub e/ ratios that are comparable to the range of angular momentum transitions having strong coupling are found to require a complete three-dimensional description, the rates of vibrational energy transfer in molecules with large ω/sub e//B/sub e/ ratios appear to be well approximated by a collinear collision model

Modeling the Conducting Stably-Stratified Layer of the Earth's Core

Science.gov (United States)

Petitdemange, L.; Philidet, J.; Gissinger, C.

2017-12-01

Observations of the Earth magnetic field as well as recent theoretical works tend to show that the Earth's outer liquid core is mostly comprised of a convective zone in which the Earth's magnetic field is generated - likely by dynamo action -, but also features a thin, stably stratified layer at the top of the core.We carry out direct numerical simulations by modeling this thin layer as an axisymmetric spherical Couette flow for a stably stratified fluid embedded in a dipolar magnetic field. The dynamo region is modeled by a conducting inner core rotating slightly faster than the insulating mantle due to magnetic torques acting on it, such that a weak differential rotation (low Rossby limit) can develop in the stably stratified layer.In the case of a non-stratified fluid, the combined action of the differential rotation and the magnetic field leads to the well known regime of `super-rotation', in which the fluid rotates faster than the inner core. Whereas in the classical case, this super-rotation is known to vanish in the magnetostrophic limit, we show here that the fluid stratification significantly extends the magnitude of the super-rotation, keeping this phenomenon relevant for the Earth core. Finally, we study how the shear layers generated by this new state might give birth to magnetohydrodynamic instabilities or waves impacting the secular variations or jerks of the Earth's magnetic field.

WHY ARE RAPIDLY ROTATING M DWARFS IN THE PLEIADES SO (INFRA)RED? NEW PERIOD MEASUREMENTS CONFIRM ROTATION-DEPENDENT COLOR OFFSETS FROM THE CLUSTER SEQUENCE

Energy Technology Data Exchange (ETDEWEB)

Covey, Kevin R. [Department of Physics and Astronomy, Western Washington University, Bellingham WA 98225-9164 (United States); Agüeros, Marcel A.; Liu, Jiyu [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Law, Nicholas M. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Ahmadi, Aida [Max Planck Institute for Radioastronomy, Auf dem Hügel 69, D-53121 Bonn (Germany); Laher, Russ; Surace, Jason [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Levitan, David [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Sesar, Branimir, E-mail: kevin.covey@wwu.edu [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

2016-05-10

Stellar rotation periods ( P {sub rot}) measured in open clusters have proved to be extremely useful for studying stars’ angular momentum content and rotationally driven magnetic activity, which are both age- and mass-dependent processes. While P {sub rot} measurements have been obtained for hundreds of solar-mass members of the Pleiades, measurements exist for only a few low-mass (<0.5 M {sub ⊙}) members of this key laboratory for stellar evolution theory. To fill this gap, we report P {sub rot} for 132 low-mass Pleiades members (including nearly 100 with M ≤ 0.45 M {sub ⊙}), measured from photometric monitoring of the cluster conducted by the Palomar Transient Factory in late 2011 and early 2012. These periods extend the portrait of stellar rotation at 125 Myr to the lowest-mass stars and re-establish the Pleiades as a key benchmark for models of the transport and evolution of stellar angular momentum. Combining our new P {sub rot} with precise BVIJHK photometry reported by Stauffer et al. and Kamai et al., we investigate known anomalies in the photometric properties of K and M Pleiades members. We confirm the correlation detected by Kamai et al. between a star's P {sub rot} and position relative to the main sequence in the cluster's color–magnitude diagram. We find that rapid rotators have redder ( V − K ) colors than slower rotators at the same V , indicating that rapid and slow rotators have different binary frequencies and/or photospheric properties. We find no difference in the photometric amplitudes of rapid and slow rotators, indicating that asymmetries in the longitudinal distribution of starspots do not scale grossly with rotation rate.

Dosimetric effects of rotational offsets in stereotactic body radiation therapy (SBRT) for lung cancer

Energy Technology Data Exchange (ETDEWEB)

Yang, Yun; Catalano, Suzanne; Kelsey, Chris R.; Yoo, David S.; Yin, Fang-Fang; Cai, Jing, E-mail: jing.cai@duke.edu

2014-04-01

To quantitatively evaluate dosimetric effects of rotational offsets in stereotactic body radiation therapy (SBRT) for lung cancer. Overall, 11 lung SBRT patients (8 female and 3 male; mean age: 75.0 years) with medially located tumors were included. Treatment plans with simulated rotational offsets of 1°, 3°, and 5° in roll, yaw, and pitch were generated and compared with the original plans. Both clockwise and counterclockwise rotations were investigated. The following dosimetric metrics were quantitatively evaluated: planning target volume coverage (PTV V{sub 100%}), max PTV dose (PTV D{sub max}), percentage prescription dose to 0.35 cc of cord (cord D{sub 0.35} {sub cc}), percentage prescription dose to 0.35 cc and 5 cc of esophagus (esophagus D{sub 0.35} {sub cc} and D{sub 5} {sub cc}), and volume of the lungs receiving at least 20 Gy (lung V{sub 20}). Statistical significance was tested using Wilcoxon signed rank test at the significance level of 0.05. Overall, small differences were found in all dosimetric matrices at all rotational offsets: 95.6% of differences were < 1% or < 1 Gy. Of all rotational offsets, largest change in PTV V{sub 100%}, PTV D{sub max}, cord D{sub 0.35} {sub cc}, esophagus D{sub 0.35} {sub cc}, esophagus D{sub 5} {sub cc}, and lung V{sub 20} was − 8.36%, − 6.06%, 11.96%, 8.66%, 6.02%, and − 0.69%, respectively. No significant correlation was found between any dosimetric change and tumor-to-cord/esophagus distances (R{sup 2} range: 0 to 0.44). Larger dosimetric changes and intersubject variations were observed at larger rotational offsets. Small dosimetric differences were found owing to rotational offsets up to 5° in lung SBRT for medially located tumors. Larger intersubject variations were observed at larger rotational offsets.

The Rotational Barrier in Ethane: A Molecular Orbital Study

Directory of Open Access Journals (Sweden)

Gonzalo J. Mena-Rejón

2012-04-01

Full Text Available The energy change on each Occupied Molecular Orbital as a function of rotation about the C-C bond in ethane was studied using the B3LYP, mPWB95 functional and MP2 methods with different basis sets. Also, the effect of the ZPE on rotational barrier was analyzed. We have found that σ and π energies contribution stabilize a staggered conformation. The σ<sub>s> molecular orbital stabilizes the staggered conformation while the  stabilizes the eclipsed conformation and destabilize the staggered conformation. The π<sub>z> and  molecular orbitals stabilize both the eclipsed and staggered conformations, which are destabilized by the π<sub>v> and  molecular orbitals. The results show that the method of calculation has the effect of changing the behavior of the energy change in each Occupied Molecular Orbital energy as a function of the angle of rotation about the C–C bond in ethane. Finally, we found that if the molecular orbital energy contribution is deleted from the rotational energy, an inversion in conformational preference occurs.

Continuous preparation of Fe{sub 3}O{sub 4} nanoparticles through Impinging Stream-Rotating Packed Bed reactor and their electrochemistry detection toward heavy metal ions

Energy Technology Data Exchange (ETDEWEB)

Fan, Hong-Lei [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China); Zhou, Shao-Feng [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan, 030051 (China); Gao, Jing [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China); Liu, You-Zhi, E-mail: lyzzhongxin@126.com [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China)

2016-06-25

We reported the continuous preparation and electrochemical behavior toward heavy metal ions of the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs). This Fe{sub 3}O{sub 4} NPs were fabricated through a novel Impinging Stream-Rotating Packed Bed reactor with a high production rate of 2.23 kg/hour. The as-prepared Fe{sub 3}O{sub 4} NPs were quasi-spherical with a mean diameter of about 10 nm and shown the characteristics of superparamagnetism with the saturated magnetization of 60.5 emu/g. The electrochemical characterization of the as-prepared Fe{sub 3}O{sub 4} NPs toward heavy metal ions were evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The results indicated that the modified electrode could be used to individual detection of Pb(II), Cu(II), Hg(II) and Cd(II). In particular, the modified electrode exhibited the selective detection toward Pb(II) with higher sensitivity of 14.9 μA/μM, while the response to Cu(II), Hg(II) and Cd(II) were negligible. Besides, the modified electrode shown good stability and potential practical applicability in the electrochemical determination of Pb(II). This above results offered a simple method for continuous preparation sensing materials in the application field of electrochemical detection of toxic metal ions through the technology of process intensification. - Highlights: • Fe{sub 3}O{sub 4} nanoparticles were continuous prepared through IS-RPB reactor. • The Fe{sub 3}O{sub 4} nanoparticles showed selective detection of heavy metal ions. • It exhibited favorable sensitivity (14.9 μA μM{sup −1}) and LOD (0.119 μM) for Pb(II). • The as-prepared nanoparticles showed favorable potential application.

Assessment of the effect of three-dimensional mantle density heterogeneity on earth rotation in tidal frequencies.

Science.gov (United States)

Liu, Lanbo; Chao, Benjamin F; Sun, Wenke; Kuang, Weijia

2016-11-01

In this paper we report the assessment of the effect of the three-dimensional (3D) density heterogeneity in the mantle on Earth Orientation Parameters (EOP) (i.e., the polar motion, or PM, and the length of day, or LOD) in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6L8) and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the Preliminary Reference Earth Model (PREM). Using this approach the effects of the heterogeneous mantle density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal) are estimated in both PM and LOD. When compared with mass or density perturbations originated on the earth's surface such as the oceanic and barometric changes, the heterogeneous mantle only contributes less than 10% of the total variation in PM and LOD in tidal frequencies. Nevertheless, including the 3D variation of the density in the mantle into account explained a substantial portion of the discrepancy between the observed signals in PM and LOD extracted from the lump-sum values based on continuous space geodetic measurement campaigns (e.g., CONT94) and the computed contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon). In other word, the difference of the two, at all tidal frequencies (long-periods, diurnals, and semi-diurnals) contains contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle density heterogeneity effect on torque-free earth rotation may provide useful constraints to construct the Reference Earth Model (REM), which is the next major objective in global geophysics research beyond PREM.

Rotation of the bulge components of barred galaxies

International Nuclear Information System (INIS)

Kormendy, J.

1982-01-01

Stellar rotation and velocity-dispersion measurements are presented for the bulge components of the SBO galaxies NGC 1023, 2859, 2950, 4340, 4371, and 7743. The kinematics of nine SB bulges with data available are compared with bulges of unbarred galaxies studied by Kormendy and Illingworth. All of the SB bulges are found to rotate at least as rapidly as oblate-spheroid dynamical models which are flattened by rotation. This result confirms the conclusion of Kormendy and Illingworth that bulges rotate very rapidly. Six SB bulges found by Kormendy and Koo to be triaxial rotate even more rapidly than the oblate models. In this respect, they resemble published n-body models of bars. That is, triaxial bulges are dynamically like bars and unlike elliptical galaxies, which are also believed to be triaxial, but which rotate slowly. Measured velocity anisotropies are found to be consistent with these conclusions. Two ordinary bulges whose rotation is well described by isotropic modes have a ratio of radial to azimuthal velocity dispersion of sigma/sub r//sigma/sub theta/ = 0.96 +- 0.03. In contrast, the triaxial bulge of NGC 3945, which rotates much faster than the isotropic models, has sigma/sub r//sigma/sub theta/ approx.1.31 +- 0.06. This is similar to the degree of anisotropy, sigma/sub r//sigma/sub theta/approx.1.21 +- 0.03, found in a recent n-body bar model by Hohl and Zang. Altogether the kinematic observations imply the triaxial bulges are more disklike than SA bulges. They appear to have been formed with more dissipation than ordinary bulges. These results are consistent with the hypothesis that part of the bulge in many SB galaxies consists of disk material (i.e., gas) which has been transported to the center by the bar. The resulting star formation may produce a very centrally concentrated light distribution which resembles a bulge but which has dislike dynamics

Sub-Doppler spectroscopy of thioformaldehyde: Excited state perturbations and evidence for rotation-induced vibrational mixing in the ground state

International Nuclear Information System (INIS)

Clouthier, D.J.; Huang, G.; Adam, A.G.; Merer, A.J.

1994-01-01

High-resolution intracavity dye laser spectroscopy has been used to obtain sub-Doppler spectra of transitions to 350 rotational levels in the 4 1 0 band of the A 1 A 2 --X 1 A 1 electronic transition of thioformaldehyde. Ground state combination differences from the sub-Doppler spectra, combined with microwave and infrared data, have been used to improve the ground state rotational and centrifugal distortion constants of H 2 CS. The upper state shows a remarkable number of perturbations. The largest of these are caused by nearby triplet levels, with matrix elements of 0.05--0.15 cm -1 . A particularly clear singlet--triplet avoided crossing in K a ' = 7 has been shown to be caused by interaction with the F 1 component of the 3 1 6 2 vibrational level of the a 3 A 2 state. At least 53% of the S 1 levels show evidence of very small perturbations by high rovibronic levels of the ground state. The number of such perturbations is small at low J, but increases rapidly beyond J=5 such that 40%--80% of the observed S 1 levels of any given J are perturbed by ground state levels. Model calculations show that the density and J dependence of the number of perturbed levels can be explained if there is extensive rotation-induced mixing of the vibrational levels in the ground state

Relative recoilless F-factors in REFeO{sub 3} (RE = rare-earth La, Pr, Nd and Sm) orthoferrites synthesized by self-combustion method

Energy Technology Data Exchange (ETDEWEB)

Morales, L.A; Sierra-Gallego, G. [Departamento de Materiales y Minerales, Facultad de Minas, Universidad Nacional de Colombia, Calle 75 # 79A-51, Bloque M17, Medellín (Colombia); Barrero, C.A. [Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia, Calle 70 No. 52-21, A.A. 1226, Medellín (Colombia); Arnache, O., E-mail: oscar.arnache@udea.edu.co [Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia, Calle 70 No. 52-21, A.A. 1226, Medellín (Colombia)

2016-09-15

Highlights: • Rare-earth orthoferrites were successfully synthesized by the self-combustion method. • The relative recoilless F-factors for REFeO{sub 3} with respect to α-Fe were calculated. • Magnetic hyperfine fields, cell volumes and Fe−O−Fe bond angles are correlated. - Abstract: In this work, rare-earth orthoferrites polycrystalline compounds REFeO{sub 3} (REFO) with RE = rare-earth La, Pr, Nd and Sm were synthesized by the self-combustion method. A direct correlation between the magnitude of the magnetic hyperfine field and the Fe−O{sub 1}−Fe bond angles was observed. From transmission Mössbauer spectra recorded at room-temperature, relative recoilless F-factors for these REFO compounds were estimated. The method applied to perform this calculation was based on the determination of two subspectral areas present in a mixture of known amounts of the compound under study and a standard sample (α-Fe). For that purpose spectra were thickness-corrected and fitted using lorentzian lines. The so obtained factors were F-{sub REFeO3} (RE = rare-earth La, Pr, Nd and Sm): 1.30 ± 0.02, 1.08 ± 0.04, 1.15 ± 0.05, 1.18 ± 0.08 respectively. The absolute recoilless factors obtained by this method had an average relative error around 11% in comparison with the values predicted by the Debye model.

Synthesis and characterization of BaAl{sub 2}O{sub 4}:Eu{sup 2+} co-doped with different rare earth ions

Energy Technology Data Exchange (ETDEWEB)

Lephoto, M.A. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Ntwaeaborwa, O.M., E-mail: ntwaeab@ufs.ac.za [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Pitale, Shreyas S.; Swart, H.C. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth, ZA 6031 (South Africa); Mothudi, B.M. [Department of Physics, University of South Africa, P.O Box 392, Pretoria, ZA 6031 (South Africa)

2012-05-15

Combustion method was used in this study to prepare BaAl{sub 2}O{sub 4}:Eu{sup 2+} phosphors co-doped with different trivalent rare-earths (Re{sup 3+}=Dy{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Sm{sup 3+}, Ce{sup 3+}, Er{sup 3+}, Pr{sup 3+} and Tb{sup 3+}) ions at an initiating temperature of 600 Degree-Sign C. The phosphors were annealed at 1000 Degree-Sign C for 3 h. As confirmed from the X-ray diffraction (XRD) data, both as prepared and post annealed samples crystallized in the well known hexagonal structure of BaAl{sub 2}O{sub 4}. All samples exhibited bluish-green emission associated with the 4f{sup 6}5d{sup 1}{yields}4f{sup 7} transitions of Eu{sup 2+} at {approx}500 nm. Although the highest intensity was observed from Er{sup 3+} co-doping, the longest afterglow (due to trapping and detrapping of charge carriers) was observed from Nd{sup 3+} followed by Dy{sup 3+} co-doping. The traps responsible for the long afterglow were studied using thermoluminescence (TL) spectroscopy.

Simultaneous rotational and vibrational CARS generation through a multiple-frequency combination technique

International Nuclear Information System (INIS)

Alden, M.; Bengtsson, P.E.; Edner, H.

1987-01-01

One most promising laser technique for probing combustion processes is coherent anti-Stokes Raman scattering (CARS), which due to its coherent nature and signal strength is applied in several real-world applications. Until today almost all CARS experiments are based on probing the population of molecular vibrational energy levels. However, there are several reasons rotational CARS, i.e. probing of rotational energy levels, may provide a complement to or even a better choice than vibrational CARS. Recently an alternative way to produce rotational CARS spectra is proposed, which is based on a multiple-frequency combination technique. The energy-level diagram for this process is presented. Two dye laser beams at ω/sub r/, and one fix frequency laser beam at ω/sub g/ are employed. ω/sub r,1/ and ω/sub r,2/ are two frequencies of many possible pairs with a frequency difference matching a rotational transition in a molecule. The excitation induced by ω/sub r,1/ and ω/sub r,2/ is then scattered by the narrowband ω/sub g/ beam resulting in a CARS beam ω/sub g/ at ω/sub g/ + ω/sub r,1/ - ω/sub r,2/. An interesting feature with this technique is that it is possible to generate simultaneously a rotational and vibrational CARS spectrum by using a double-folded boxcars phase matching approach. The authors believe that the proposed technique for producing rotational and vibration CARS spectra could be of interest, e.g., when measuring in highly turbulent flows. In this case the rotational CARS spectra could use for temperature measurements in the cooler parts, whereas vibrational CARS are to be preferred when measuring in the hotter parts

Structural, magnetic, and electronic properties of iron selenide Fe{sub 6-7}Se{sub 8} nanoparticles obtained by thermal decomposition in high-temperature organic solvents

Energy Technology Data Exchange (ETDEWEB)

Lyubutin, I. S., E-mail: lyubutinig@mail.ru, E-mail: crlin@mail.npue.edu.tw; Funtov, K. O.; Dmitrieva, T. V.; Starchikov, S. S. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Lin, Chun-Rong, E-mail: lyubutinig@mail.ru, E-mail: crlin@mail.npue.edu.tw [Department of Applied Physics, National Pingtung University of Education, Pingtung 90003, Taiwan (China); Siao, Yu-Jhan [Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan (China); Chen, Mei-Li [Department of Electro-optical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan (China)

2014-07-28

Iron selenide nanoparticles with the NiAs-like crystal structure were synthesized by thermal decomposition of iron chloride and selenium powder in a high-temperature organic solvent. Depending on the time of the compound processing at 340 °C, the nanocrystals with monoclinic (M)-Fe{sub 3}Se{sub 4} or hexagonal (H)-Fe{sub 7}Se{sub 8} structures as well as a mixture of these two phases can be obtained. The magnetic behavior of the monoclinic and hexagonal phases is very different. The applied-field and temperature dependences of magnetization reveal a complicated transformation between ferrimagnetic (FRM) and antiferromagnetic (AFM) structures, which can be related to the spin rotation process connected with the redistribution of cation vacancies. From XRD and Mössbauer data, the 3c type superstructure of vacancy ordering was found in the hexagonal Fe{sub 7}Se{sub 8}. Redistribution of vacancies in Fe{sub 7}Se{sub 8} from random to ordered leads to the transformation of the magnetic structure from FRM to AFM. The Mössbauer data indicate that vacancies in the monoclinic Fe{sub 3}Se{sub 4} prefer to appear near the Fe{sup 3+} ions and stimulate the magnetic transition with the rotation of the Fe{sup 3+} magnetic moments. Unusually high coercive force H{sub c} was found in both (H) and (M) nanocrystals with the highest (“giant”) value of about 25 kOe in monoclinic Fe{sub 3}Se{sub 4}. This is explained by the strong surface magnetic anisotropy which is essentially larger than the core anisotropy. Such a large coercivity is rare for materials without rare earth or noble metal elements, and the Fe{sub 3}Se{sub 4}-based compounds can be the low-cost, nontoxic alternative materials for advanced magnets. In addition, an unusual effect of “switching” of magnetization in a field of 10 kOe was found in the Fe{sub 3}Se{sub 4} nanoparticles below 280 K, which can be important for applications.

The O{sub 2} A-Band in the Fluxes and Polarization of Starlight Reflected by Earth-Like Exoplanets

Energy Technology Data Exchange (ETDEWEB)

Fauchez, Thomas [Laboratoire d’Optique Atmosphèrique (LOA), UMR 8518, Université Lille 1, Villeneuve d’Ascq (France); Rossi, Loic; Stam, Daphne M. [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)

2017-06-10

Earth-like, potentially habitable exoplanets are prime targets in the search for extraterrestrial life. Information about their atmospheres and surfaces can be derived by analyzing the light of the parent star reflected by the planet. We investigate the influence of the surface albedo A {sub s}, the optical thickness b {sub cloud}, the altitude of water clouds, and the mixing ratio of biosignature O{sub 2} on the strength of the O{sub 2} A-band (around 760 nm) in the flux and polarization spectra of starlight reflected by Earth-like exoplanets. Our computations for horizontally homogeneous planets show that small mixing ratios ( η < 0.4) will yield moderately deep bands in flux and moderate-to-small band strengths in polarization, and that clouds will usually decrease the band depth in flux and the band strength in polarization. However, cloud influence will be strongly dependent on properties such as optical thickness, top altitude, particle phase, coverage fraction, and horizontal distribution. Depending on the surface albedo and cloud properties, different O{sub 2} mixing ratios η can give similar absorption-band depths in flux and band strengths in polarization, especially if the clouds have moderate-to-high optical thicknesses. Measuring both the flux and the polarization is essential to reduce the degeneracies, although it will not solve them, especially not for horizontally inhomogeneous planets. Observations at a wide range of phase angles and with a high temporal resolution could help to derive cloud properties and, once those are known, the mixing ratio of O{sub 2} or any other absorbing gas.

TWO NEARBY SUB-EARTH-SIZED EXOPLANET CANDIDATES IN THE GJ 436 SYSTEM

International Nuclear Information System (INIS)

Stevenson, Kevin B.; Harrington, Joseph; Lust, Nate B.; Blecic, Jasmina; Hardy, Ryan A.; Cubillos, Patricio; Campo, Christopher J.; Lewis, Nikole K.; Montagnier, Guillaume; Moses, Julianne I.; Visscher, Channon

2012-01-01

We report the detection of UCF-1.01, a strong exoplanet candidate with a radius 0.66 ± 0.04 times that of Earth (R ⊕ ). This sub-Earth-sized planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 ± 8 × 10 –6 days. We also report evidence of a 0.65 ± 0.06 R ⊕ exoplanet candidate (labeled UCF-1.02) orbiting the same star with an undetermined period. Using the Spitzer Space Telescope, we measure the dimming of light as the planets pass in front of their parent star to assess their sizes and orbital parameters. If confirmed today, UCF-1.01 and UCF-1.02 would be designated GJ 436c and GJ 436d, respectively, and would be part of the first multiple-transiting-planet system outside of the Kepler field. Assuming Earth-like densities of 5.515 g cm –3 , we predict both candidates to have similar masses (∼0.28 Earth-masses, M ⊕ , 2.6 Mars-masses) and surface gravities of ∼0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium temperature (T eq , where emitted and absorbed radiation balance for an equivalent blackbody) is 860 K, making the planet unlikely to harbor life as on Earth. Its weak gravitational field and close proximity to its host star imply that UCF-1.01 is unlikely to have retained its original atmosphere; however, a transient atmosphere is possible if recent impacts or tidal heating were to supply volatiles to the surface. We also present additional observations of GJ 436b during secondary eclipse. The 3.6 μm light curve shows indications of stellar activity, making a reliable secondary eclipse measurement impossible. A second non-detection at 4.5 μm supports our previous work in which we find a methane-deficient and carbon monoxide-rich dayside atmosphere.

Two nearby Sub-Earth-sized Exoplanet Candidates in the GJ 436 System

Science.gov (United States)

Stevenson, Kevin B.; Harrington, Joseph; Lust, Nate B.; Lewis, Nikole K.; Montagnier, Guillaume; Moses, Julianne I.; Visscher, Channon; Blecic, Jasmina; Hardy, Ryan A.; Cubillos, Patricio; Campo, Christopher J.

2012-08-01

We report the detection of UCF-1.01, a strong exoplanet candidate with a radius 0.66 ± 0.04 times that of Earth (R ⊕). This sub-Earth-sized planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 ± 8 × 10-6 days. We also report evidence of a 0.65 ± 0.06 R ⊕ exoplanet candidate (labeled UCF-1.02) orbiting the same star with an undetermined period. Using the Spitzer Space Telescope, we measure the dimming of light as the planets pass in front of their parent star to assess their sizes and orbital parameters. If confirmed today, UCF-1.01 and UCF-1.02 would be designated GJ 436c and GJ 436d, respectively, and would be part of the first multiple-transiting-planet system outside of the Kepler field. Assuming Earth-like densities of 5.515 g cm-3, we predict both candidates to have similar masses (~0.28 Earth-masses, M ⊕, 2.6 Mars-masses) and surface gravities of ~0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium temperature (T eq, where emitted and absorbed radiation balance for an equivalent blackbody) is 860 K, making the planet unlikely to harbor life as on Earth. Its weak gravitational field and close proximity to its host star imply that UCF-1.01 is unlikely to have retained its original atmosphere; however, a transient atmosphere is possible if recent impacts or tidal heating were to supply volatiles to the surface. We also present additional observations of GJ 436b during secondary eclipse. The 3.6 μm light curve shows indications of stellar activity, making a reliable secondary eclipse measurement impossible. A second non-detection at 4.5 μm supports our previous work in which we find a methane-deficient and carbon monoxide-rich dayside atmosphere.

Aryabhata and Axial Rotation of Earth

Indian Academy of Sciences (India)

is the time taken by the Sun to go around the Earth ..... merely to aid the memory, - they were able to memorise huge prose Brahmanas quite as ... short vowel and its corresponding long vowel (this step was taken probably to avoid confusion.

Thermoluminescent analysis of CaSO{sub 4} composites activated with rare earths; Analise termoluminescente de compositos de CaSO{sub 4} ativado com terras raras

Energy Technology Data Exchange (ETDEWEB)

Junot, D.O.; Chagas, M.A.P.; Souza, D.N., E-mail: danilo.junot@hotmail.com, E-mail: mchagasfisica@gmail.com, E-mail: divanizi@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Fisica

2013-07-01

Since the thermoluminescence started to be applied to the dosimetry of ionizing radiation in 1940 different materials detectors have been proposed, and one of the most common is CaSO{sub 4}. The motivation of this work was to produce crystals of CaSO{sub 4} doped with rare earth elements such as europium (Eu), neodymium (Nd) and thulium (Tm). It was also produced crystals of CaSO{sub 4}:Ag. The interest in the production of these materials was to investigate other methods of production of thermoluminescent materials. The results show that the CaSO{sub 4}:Tm is more suitable for use in the thermoluminescent dosimetry. Although not the most intense peak, the peak at 170 °C could be a dosimetric peak. Analyses showed that all samples have a TL response proportional to the dose absorbed. (author)

Reaction kinetics of H{sub 2}, O{sub 2}, and H{sub 2}O with rare earths (Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er) at 298 K

Energy Technology Data Exchange (ETDEWEB)

Enomoto, M.; Ohata, Y. [Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan); Uchida, H., E-mail: huchida@keyaki.cc.u-tokai.ac.jp [Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan)

2013-12-15

Highlights: ► H{sub 2} molecules react with a clean surface of each RE sample at the highest reactivity even at 298 K. ► The H{sub 2} reactivity becomes reduced by the formation of dihydrides of each RE sample. ► The RE with a clean surface adsorb O{sub 2} more than one monolayer of O{sub 2} even at 298 K. ► The quantitative reactivity of the H atoms dissociated from H{sub 2}O was calculated. -- Abstract: High reactivity of rare earths (RE) with H{sub 2}, O{sub 2} and H{sub 2}O is well known even at room temperature. The formation of stable surface oxides/hydroxides on the surface is the one of serious problems in the production and use of materials containing RE. We have investigated the quantitative reactivities of H{sub 2}, O{sub 2}, and H{sub 2}O with the surface of Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er under ultra high vacuum condition. The H{sub 2}, O{sub 2} and H{sub 2}O gases exhibited the highest reactivity on the clean surface of the RE at 298 K. This means that all gas molecules impinging the surface dissociate and chemisorbed. The O atoms dissociated from O{sub 2} adsorb to for oxides layers of the metals. The H atoms dissociated from H{sub 2} diffuse into the metals to form hydrides which were found to decrease the H{sub 2} reactivity. The H atoms dissociated form H{sub 2}O diffuse into the metals or form hydroxides of the metals. With increasing coverage of each gas molecules, the reactivity of each gas was decreased by several orders of magnitude.

Organic Aerosols in the Presence of CO{sub 2} in the Early Earth and Exoplanets: UV–Vis Refractive Indices of Oxidized Tholins

Energy Technology Data Exchange (ETDEWEB)

Gavilan, Lisseth; Carrasco, Nathalie; Vettier, Ludovic [LATMOS, Université Versailles St Quentin, UPMC Université Paris 06, CNRS, 11 blvd d’Alembert, F-78280 Guyancourt (France); Broch, Laurent [LCP-A2MC, Institut Jean Barriol, Université de Lorraine, Metz (France); Fleury, Benjamin, E-mail: lisseth.gavilan@latmos.ipsl.fr [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2017-10-10

In this experimental study we investigate the role of atmospheric CO{sub 2} on the optical properties of organic photochemical aerosols. To this end, we add CO{sub 2} to a N{sub 2}:CH{sub 4} gas mixture used in a plasma typically used for Titan studies. We produce organic thin films (tholins) in plasmas where the CO{sub 2}/CH{sub 4} ratio is increased from 0 to 4. We measure these films via spectrometric ellipsometry and apply a Tauc–Lorentz model, used for optically transparent materials, to obtain the thickness of the thin film, its optical band gap, and the refractive indices in the UV–visible (270–600 nm). All samples present a significant absorption band in the UV. According to the Tauc–Lorentz model, as the CO{sub 2}/CH{sub 4} ratio is quadrupled, the position of the UV band is shifted from ∼177 nm to 264 nm while its strength is quadrupled. Consequently, we infer that oxidized organic aerosols absorb more efficiently at longer UV wavelengths than reduced aerosols. Our laboratory wavelength-tabulated UV–vis refractive indices provide new constraints to atmospheric models of the early Earth and Earth-like exoplanets including photochemical hazes formed under increasingly oxidizing conditions.

A rotating bag model for hadrons. 2

International Nuclear Information System (INIS)

Iwasaki, Masaharu

1994-01-01

The MIT bag model is modified in order to describe rotational motion of hadrons. It has a kind of 'diatomic molecular' structure; The rotational excitation of the MIT bag is described by the polarized two colored sub-bags which are connected with each other by the gluon flux. One sub-bag contains a quark and the other has an antiquark for mesons. For baryons, the latter sub-bag contains the remaining two quarks instead of the antiquark. The Regge trajectories of hadrons are explained qualitatively by our new model with the usual MIT bag parameters. In particular the Regge slopes are reproduced fairly well. It is also pointed out that the gluon flux plays an important role in the rotational motion of hadrons. (author)

Some thermoelectric properties of the light rare earth sesquiselenides (R2Se/sub 3-x/)

International Nuclear Information System (INIS)

Takeshita, T.; Beaudry, B.J.; Gschneidner, K.A. Jr.

1981-01-01

Rare earth sesquiselenides of the Th 3 P 4 structure show variable electric properties over their homogeneity range, i.e., ranging from metallic (R 3 Se 4 ) to semimetallic (R 2 Se/sub 3-x/, where 0.14 > x > 0) to semiconducting (R 2 Se 3 ). The composition change is due to the formation of metal vacancies in the Th 3 P 4 structure with no vacancies at R 3 Se 4 and 4.75 at. % vacancies at R 2 Se 3 . The rare earth sesquiselenides are also refractory materials and therefore are of interest for high temperature thermoelectric applications. Preliminary results of thermoelectric power and electrical resistivity measurements on the light lanthanide sesquiselenides (La through Sm) are presented

When a Slowly Rotating Aquaplanet is Coupled to a Dynamical Ocean

Science.gov (United States)

Salameh, J.; Marotzke, J.

2017-12-01

Planets orbiting in close distance from their stars have a high probability to be detected, and are expected to be slowly rotating due to strong tidal forces. By increasing the rotation period from 1 Earth-day to 365 Earth-days, we previously found that the global-mean surface temperature of an aquaplanet with a static mixed-layer ocean decreases by up to 27 K. The cooling is attributed to an increase of the planetary albedo with the rotation period, which is associated with the different distributions of the sea ice and the deep convective clouds. However, we had there assumed a fixed mixed-layer depth and a zero oceanic heat transport in the aquaplanet configuration. The limitations of these assumptions in such exotic climates are still unclear. We therefore perform coupled atmosphere-ocean aquaplanet simulations with the general circulation model ICON for various rotation periods ranging from 1 Earth-day to 365 Earth-days. We investigate how the underlying oceanic circulation modifies the mean climate of slowly rotating aquaplanets, and whether the day-to-night oceanic heat transport reduces the surface-temperature gradients and the sea-ice extent.

Millimeter/submillimeter spectroscopy of PH{sub 2}CN ( X-tilde {sup 1}A') and CH{sub 3}PH{sub 2} ( X-tilde {sup 1}A'): probing the complexity of interstellar phosphorus chemistry

Energy Technology Data Exchange (ETDEWEB)

Halfen, D. T.; Ziurys, L. M. [Department of Chemistry and Biochemistry, Department of Astronomy, Arizona Radio Observatory, and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Clouthier, D. J., E-mail: halfendt@as.arizona.edu [Department of Chemistry, University of Kentucky, Lexington, KY 40506 (United States)

2014-11-20

Millimeter/submillimeter spectra of PH{sub 2}CN ( X-tilde {sup 1}A') and CH{sub 3}PH{sub 2} ( X-tilde {sup 1}A') have been recorded for the first time using direct absorption techniques. This work extends previous measurements of both molecules beyond the 10-50 GHz range. Both species were created in the presence of an AC discharge by the reaction of phosphorus vapor and either cyanogen and hydrogen (PH{sub 2}CN) or methane (CH{sub 3}PH{sub 2}). Twelve rotational transitions of PH{sub 2}CN were recorded over the region 305-422 GHz for asymmetry components K{sub a} = 0 through 8. For CH{sub 3}PH{sub 2}, eight rotational transitions were measured from 210-470 GHz with K{sub a} = 0 through 16; these spectra exhibited greater complexity due to the presence of internal rotation, which splits the K{sub a} = 1, 2, and 3 asymmetry components into A and E states. Combined analyses of the millimeter/submillimeter and previous microwave data were performed for both molecules. For PH{sub 2}CN, the spectra were fit with a Watson S-reduced asymmetric top Hamiltonian, resulting in more accurate rotational and centrifugal distortion constants. In the case of CH{sub 3}PH{sub 2}, an asymmetric top internal-rotation Hamiltonian was employed in the analysis, significantly improving the rotational and torsional parameters over previous microwave estimates. Searches for both molecules were subsequently conducted toward Sgr B2(N), using the 12 m telescope of the Arizona Radio Observatory (ARO). Neither species was identified, with abundance upper limits, relative to H{sub 2}, of f (PH{sub 2}CN/H{sub 2}) < 7.0 × 10{sup –12} and f (CH{sub 3}PH{sub 2}/H{sub 2}) < 8.4 × 10{sup –12}. The nitrogen analogs NH{sub 2}CN and CH{sub 3}NH{sub 2} are therefore more abundant in Sgr B2(N) by factors of >2 and >200, respectively.

Tutorial on earthquake rotational effects: historical examples

Czech Academy of Sciences Publication Activity Database

Kozák, Jan

2009-01-01

Roč. 99, 2B (2009), s. 998-1010 ISSN 0037-1106 Institutional research plan: CEZ:AV0Z30120515 Keywords : rotational seismic models * earthquake rotational effects * historical earthquakes Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.860, year: 2009

Can planetary nebulae rotate

International Nuclear Information System (INIS)

Grinin, V.P.

1982-01-01

It is shown that the inclination of spectral lines observed in a number of planetary nebulae when the spectrograph slit is placed along the major axis, which is presently ascribed to nonuniform expansion of the shells, actually may be due to rotation of the nebulae about their minor axes, as Campbell and Moore have suggested in their reports. It is assumed that the rotation of the central star (or, if the core is a binary system, circular motions of gas along quasi-Keplerian orbits) serves as the source of the original rotation of a protoplanetary nebula. The mechanism providing for strengthening of the original rotation in the process of expansion of the shell is the tangential pressure of L/sub α/ radiation due to the anisotropic properties of the medium and radiation field. The dynamic effect produced by them is evidently greatest in the epoch when the optical depth of the nebula in the L/sub c/ continuum becomes on the order of unity in the course of its expansion

Fast online replanning for interfraction rotation correction in prostate radiotherapy.

Science.gov (United States)

Kontaxis, Charis; Bol, Gijsbert H; Kerkmeijer, Linda G W; Lagendijk, Jan J W; Raaymakers, Bas W

2017-10-01

To enable fast online replanning for prostate radiotherapy with the inclusion of interfraction rotations and translations and investigate the possibility for margin reduction via this regime. Online daily replanning for a 35-fraction treatment for five prostate cases is simulated while accounting for anatomical transformations derived from fiducial marker data available in our clinic. Two online replanning strategies were simulated, compensating for: (a) rotation-only in combination with a couch shift and (b) both translation and rotation without a couch shift. They were compared against our current clinical protocol consisting of a single offline plan used over all fractions with daily couch repositioning (translations only). For every patient, the above methods were generated for several planning margins (0-8 mm with 2 mm increments) in order to assess the performance of online replanning in terms of target coverage and investigate the possible dosimetric benefit for the organs at risk. The daily DVHs for each treatment strategy were used for evaluation and the non tumor integral dose (NTID) for the different margins was calculated in order to quantify the overall reduction of the delivered energy to the patient. Our system is able to generate a daily automated prostate plan in less than 2 min. For every patient, the daily treatment plans produce similar dose distributions to the original approved plan (average CTV D99 relative difference: 0.2%). The inclusion of both shifts and rotations can be effectively compensated via replanning among all planning margins (average CTV D99 difference: 0.01 Gy between the two replanning regimes). Online replanning is able to maintain target coverage among all margins, while - as expected - the conventional treatment plan is increasingly affected by the interfraction rotations as the margins shrink (average CTV D99 decrease: 0.2 Gy at 8 mm to 2.9 Gy at 0 mm margin). The possible gain in total delivered energy to the patient was

Squeezing clathrate cages to host trivalent rare-earth guests

Energy Technology Data Exchange (ETDEWEB)

Wang, Jian [Iowa State Univ., Ames, IA (United States). Department of Chemistry; Ames Lab., Ames, IA (United States); He, Yuping [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Mordvinova, Natalia E. [Laboratoire CRISMAT, ENSICAEN, CNRS UMR (France); Lebedev, Oleg [Laboratoire CRISMAT, ENSICAEN, CNRS UMR (France); Kovnir, Kirill [Iowa State Univ., Ames, IA (United States). Department of Chemistry; Ames Lab., Ames, IA (United States)

2017-11-01

Strike difference of the trivalent rare-earth cations from their alkali and alkaline-earth peers is in the presence of localized 4f-electrons and strong spin-orbit coupling. Placing trivalent rare-earth cations inside the fullerene molecules or in between the blocks of itinerant magnetic intermetallics gave rise to plethora of fascinating properties and materials. A long-time missing but hardly desired piece is the semiconducting or metallic compound where rare-earth cations are situated inside the oversized polyhedral cages of three-dimensional framework. In this work we present a synthesis of such compounds, rare-earth containing clathrates Ba<sub>8-xsub>R_xCu>16sub>P>30sub>. The unambiguous proofs of their composition and crystal structure were achieved by a combination of synchrotron powder diffraction, time-of-flight neutron powder diffraction, scanning-transmission electron microscopy, and electron energy-loss spectroscopy. Our quantum-mechanical calculations and experimental characterizations show that the incorporation of the rare-earth cations significantly enhances the hole mobility and concentration which results in the drastic increase in the thermoelectric performance.

Electronic and magnetic structure of RENi{sub 2}Mn{sub x}-compounds (RE = rare earth, x = 0, 0.25, 0.5, 0.75, 1, 1.25) with respect to ErNi{sub 2}Mn{sub x}

Energy Technology Data Exchange (ETDEWEB)

Balinski, Kamil; Kuepper, Karsten [Department of Physics, Osnabrueck University (Germany); Chrobak, Artur [Department of Physics, University of Silesia in Katowice (Poland); Kuznetzsova, T.V.; Mushnikov, N.V.; Marchenkov, V.V. [Institute of Metal Physics, 620990 Ekaterinburg (Russian Federation)

2015-07-01

Rare earth (RE) and transition metal (T) compounds are research field since the 1960s. Because of huge magnetocalorical effect and giant magnetostriction the RE-T-compounds are excellent for applications like magnetic cooling or hydrogen storage devices. Besides of that RE-Ni{sub 2}-type of alloys are, due to the relatively simple crystal structure and the fact that Ni{sub 2} does not indicate any %behavior with result in an magnetic moment, excellent candidates for studies of magnetic behavior of RE's and their binding partners. The electronic structure of ErNi{sub 2}Mn{sub x} (x = 0, 0.25, 0.5, 0.75, 1, 1.25) is characterized by XPS and ResPES, the magnetic structure is investigated by SQUID and PPMS techniques, and resistivity measurements are made. Variation in Mn concentration revealed the position of Mn 3d-states at 1.7 eV. The XPS intensity at 1.7 eV can be correlated with the behavior of the Curie temperature and the resistivity. While similar RENi{sub 2}Mn{sub x}-systems, where RE had been replaced by Gd and Tb, highest resistivity, Curie temperature and the highest Mn 3d-valence band state intensity were observed at x = 0.5. ErNi{sub 2}Mn{sub x}-system behave different and show the mentioned maxima at x = 1.25.

Rotating disk atomization of Gd and Gd-Y for hydrogen liquefaction via magnetocaloric cooling

Energy Technology Data Exchange (ETDEWEB)

Slinger, Tyler [Iowa State Univ., Ames, IA (United States)

2016-12-17

In order to enable liquid hydrogen fuel cell technologies for vehicles the cost of hydrogen liquefaction should be lowered. The current method of hydrogen liquefaction is the Claude cycle that has a figure of merit (FOM) of 0.3-0.35. New magnetocaloric hydrogen liquefaction devices have been proposed with a FOM>0.5, which is a significant improvement. A significant hurdle to realizing these devices is the synthesis of spherical rare earth based alloy powders of 200μm in diameter. In this study a centrifugal atomization method that used a rotating disk with a rotating oil quench bath was developed to make gadolinium and gadolinium-yttrium spheres. The composition of the spherical powders included pure Gd and Gd<sub>0.91sub>Y>0.09sub>. The effect of atomization parameters, such as superheat, melt properties, disk shape, disk speed, and melt system materials and design, were investigated on the size distribution and morphology of the resulting spheres. The carbon, nitrogen, and oxygen impurity levels also were analyzed and compared with the magnetic performance of the alloys. The magnetic properties of the charge material as well as the resulting powders were measured using a vibrating sample magnetometer. The saturation magnetization and Curie temperature were the target properties for the resulting spheres. These values were compared with measurements taken on the charge material in order to investigate the effect of atomization processing on the alloys.

Earth - South America (first frame of Earth Spin Movie)

Science.gov (United States)

1990-01-01

This color image of the Earth was obtained by Galileo at about 6:10 a.m. Pacific Standard Time on Dec. 11, 1990, when the spacecraft was about 1.3 million miles from the planet during the first of two Earth flybys on its way to Jupiter. The color composite used images taken through the red, green and violet filters. South America is near the center of the picture, and the white, sunlit continent of Antarctica is below. Picturesque weather fronts are visible in the South Atlantic, lower right. This is the first frame of the Galileo Earth spin movie, a 500- frame time-lapse motion picture showing a 25-hour period of Earth's rotation and atmospheric dynamics.

Luminescent phosphors, based on rare earth substituted oxyfluorides in the A(1){sub 3-x} A(2){sub x}MO{sub 4}F family with A(1)/A(2)=Sr, Ca, Ba and M=Al, Ga

Energy Technology Data Exchange (ETDEWEB)

Park, Sangmoon, E-mail: spark@silla.ac.k [Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Vogt, Thomas [NanoCenter and Department of Chemistry and Biochemistry, University of South Carolina, Columbia 29208, SC (United States)

2009-09-15

A new family of UV-activated phosphors made by substituting rare-earth activators such as trivalent Eu, Tb, Tm and Er into A(1){sub 3-x}A(2){sub x}MO{sub 4}F host lattices (A(1)/A(2)=Sr, Ca, Ba; M=Al, Ga) are introduced and their activation and emission spectra as well as their CIE values reported. The Tm-substituted system can be activated using light with a wavelength of 360 nm. Relative intensities of a family of Tb-substituted green phosphors activated at 254 nm and with emissions centered near 548 nm are discussed.

Magnetoelastic interaction in rare earth systems

International Nuclear Information System (INIS)

Dohm, V.

1975-01-01

A theory of rotationally invariant spin-lattice interactions in rare earth systems is presented. It is shown that rotational invariance to leading order is ensured only if rotational interactions of first and second order in the displacements are included simultaneously in the spin-lattice Hamiltonian. The rotational second-order interactions yield effects which are as large as those of the linear rotational interaction. It is pointed out that a corresponding statement should hold also for pure strain interactions. The phonon Green's function is calculated for the paramagnetic phase of rare earth systems. It is found that in an applied magnetic field the rotational interactions cause measureable changes of the phonon dispersion and the sound velocity even for cubic symmetry. These effects turn out to be of the same order of magnitude as the conventional field-dependent strain effects and are qualitatively different from the latter. The results of our theory are illustrated by the example of SmSb, and quantitative predictions for the transverse sound velocities are given. (orig.) [de

Superstructure formation in PrNi{sub 2}Al{sub 3} and ErPd{sub 2}Al{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Eustermann, Fabian; Hoffmann, Rolf-Dieter [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Oldenburg Univ. (Germany). Inst. fuer Chemie

2017-09-01

The intermetallic phase ErPd{sub 2}Al{sub 3} was obtained by arc-melting of the elements and subsequent annealing for crystal growth. The sample was studied by X-ray diffraction on powders and single crystals. The structure of ErPd{sub 2}Al{sub 3} was refined from X-ray diffraction data and revealed a superstructure of PrNi{sub 2}Al{sub 3} - a CaCu{sub 5} derivative (P6/m, a=1414.3(1), c=418.87(3) pm wR=0.0820, 1060 F{sup 2} values, 48 variables). The same superstructure was subsequently found for PrNi{sub 2}Al{sub 3} (P6/m, a=1407.87(4), c=406.19(2) pm, wR=0.0499, 904 F{sup 2} values, 47 variables). In the crystal structure, the aluminium and transition metal atoms form a polyanionic network according to [T{sub 2}Al{sub 3}]{sup δ-}, while rare earth atoms fill cavities within the networks. They are coordinated by six transition metal and twelve aluminum atoms. In contrast to the PrNi{sub 2}Al{sub 3} type structure reported so far, two crystallographic independent rare-earth sites are found of which one (1b) is shifted by 1/2 z, causing a distortion in the structure along with a recoloring of the T and Al atoms in the network.

Properties of an Earth-like planet orbiting a Sun-like star: Earth observed by the EPOXI mission.

Science.gov (United States)

Livengood, Timothy A; Deming, L Drake; A'hearn, Michael F; Charbonneau, David; Hewagama, Tilak; Lisse, Carey M; McFadden, Lucy A; Meadows, Victoria S; Robinson, Tyler D; Seager, Sara; Wellnitz, Dennis D

2011-11-01

NASA's EPOXI mission observed the disc-integrated Earth and Moon to test techniques for reconnoitering extrasolar terrestrial planets, using the Deep Impact flyby spacecraft to observe Earth at the beginning and end of Northern Hemisphere spring, 2008, from a range of ∼1/6 to 1/3 AU. These observations furnish high-precision and high-cadence empirical photometry and spectroscopy of Earth, suitable as "ground truth" for numerically simulating realistic observational scenarios for an Earth-like exoplanet with finite signal-to-noise ratio. Earth was observed at near-equatorial sub-spacecraft latitude on 18-19 March, 28-29 May, and 4-5 June (UT), in the range of 372-4540 nm wavelength with low visible resolving power (λ/Δλ=5-13) and moderate IR resolving power (λ/Δλ=215-730). Spectrophotometry in seven filters yields light curves at ∼372-948 nm filter-averaged wavelength, modulated by Earth's rotation with peak-to-peak amplitude of ≤20%. The spatially resolved Sun glint is a minor contributor to disc-integrated reflectance. Spectroscopy at 1100-4540 nm reveals gaseous water and carbon dioxide, with minor features of molecular oxygen, methane, and nitrous oxide. One-day changes in global cloud cover resulted in differences between the light curve beginning and end of ≤5%. The light curve of a lunar transit of Earth on 29 May is color-dependent due to the Moon's red spectrum partially occulting Earth's relatively blue spectrum. The "vegetation red edge" spectral contrast observed between two long-wavelength visible/near-IR bands is ambiguous, not clearly distinguishing between the verdant Earth diluted by cloud cover versus the desolate mineral regolith of the Moon. Spectrophotometry in at least one other comparison band at short wavelength is required to distinguish between Earth-like and Moon-like surfaces in reconnaissance observations. However, measurements at 850 nm alone, the high-reflectance side of the red edge, could be sufficient to

Rotation and solvation of ammonium ion

International Nuclear Information System (INIS)

Perrin, C.L.; Gipe, R.K.

1987-01-01

From nitrogen-15 spin-lattice relaxation times and nuclear Overhauser enhancements, the rotational correlations time tau/sub c/ for 15 NH 4 + was determined in s series of solvents. Values of tau/sub c/ range from 0.46 to 20 picoseconds. The solvent dependent of tau/sub c/ cannot be explained in terms of solvent polarity, molecular dipole moment, solvent basicity, solvent dielectric relaxation, or solvent viscosity. The rapid rotation and the variation with solvent can be accounted for by a model that involves hydrogen bonding of an NH proton to more than one solvent molecule in a disordered solvation environment. 25 references, 1 table

Dayak and Their Daily Life

Directory of Open Access Journals (Sweden)

Hamid Darmadi

2017-03-01

Full Text Available This article titled "Dayak and Daily Life" This paper aims to reveal the Dayak and in their daily life. Dayak is a native of Borneo has its own characteristics. Dayak, divided into 405 sub-sub clans [1]. Each sub Dayak both Indonesia and Malaysia are identical. Dayak customs and culture comes from the word "Power" which means upstream, to refer to people who live in inland areas or in the interior of Borneo. In the arsenal of art and culture, Dayak has many similarities such as; saber, chopsticks, beliong, betang, cupai, renjung, empajang and others. Dayak indigenous religion is Kaharingan which is the original religion born of the cultural ancestors of the Dayaks. Most of the Dayak people still adhere to the belief of the existence of unseen objects in certain places such as rocks, large trees, planting gardens in the forest, lakes, pools, and others are believed to have "magical powers". Daily life of the Dayaks in general farming, farming. When will open farming land, farming they held ritual.

Ultra-flexible framework breathing in response to dehydration in liskeardite, [(Al,Fe){sub 16}(AsO{sub 4}){sub 9}(OH){sub 21}(H{sub 2}O){sub 11}]·26H{sub 2}O, a natural open-framework compound

Energy Technology Data Exchange (ETDEWEB)

Grey, Ian. E., E-mail: Ian.Grey@csiro.au [CSIRO Mineral Resources, Private Bag 10, Clayton South, VIC 3169 (Australia); Brand, Helen E.A. [Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168 (Australia); Rumsey, Michael S. [Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Gozukara, Yesim [CSIRO Manufacturing, Private Bag 10, Clayton South, VIC 3169 (Australia)

2015-08-15

Dehydration of the natural open-framework compound, liskeardite, [(Al,Fe){sub 16}(AsO{sub 4}){sub 9}(OH){sub 21}(H{sub 2}O){sub 11}]·26H{sub 2}O, is accompanied by a change in the sign of the thermal expansion from positive to negative above room temperature, and at ~100 °C the structure undergoes a dramatic 2D contraction by co-operative rotation of heteropolyhedral columns that constitute the framework walls. Monoclinic liskeardite, I112 with a≈b≈24.7 Å, c ≈7.8 Å and β≈90° is transformed to a tetragonal phase, I-4 with a≈20.6 Å, c ≈7.7 Å. The associated 30% decrease in volume is unprecedented in inorganic microporous compounds. The flexibility of the contraction is related to the double-hinged nature of the column rotations about [001]. Octahedra in adjacent columns are interconnected by corner-sharing with the two pairs of anions forming opposing edges of AsO{sub 4} tetrahedra, so a double-hinged rotation mechanism operates. Thermal analysis and mass spectroscopic results for liskeardite show that the phase transition at ~100 °C is related to removal of the channel water. The tetragonal phase shows exceptionally large NTE behaviour. Over the temperature range 148–178 the NTE along a and b is close to linear with a magnitude of the order of −900×10{sup −6} °C{sup −1}. The contraction along the channel direction is smaller but still appreciable at −200×10{sup −6} °C{sup −1}. - Graphical abstract: Structure of the collapsed liskeardite framework, formed on dehydration above 100 °C. - Highlights: • The thermal expansion of the mineral liskeardite changes + to − above ambient. • Dehydration at 100 °C results in a record reversible 30% volume reduction. • In situ synchrotron XRD has led to a structural model for the dehydrated phase. • Framework breathing flexibility is attributed to a double-hinge rotation mechanism. • The dehydrated phase shows unprecedented -ve expansion for inorganic materials.

Formation of Self-Assembled Ba<sub>2sub>YNbO>6sub> Nanocolumns and their Contribution to Flux-Pinning and J<sub>c> in Nb-doped YBa<sub>2sub>Cu>3sub>O>7- sub> Films

Energy Technology Data Exchange (ETDEWEB)

Wee, Sung Hun [ORNL; Goyal, Amit [ORNL; Zuev, Yuri L [ORNL; Cantoni, Claudia [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Specht, Eliot D [ORNL

2010-01-01

Ba{sub 2}RENbO{sub 6} (RE = rare earth elements including Y) compounds are considered new additives for superior flux-pinning in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films due to their excellent chemical inertness to and large lattice mismatches with YBCO. Simultaneous laser ablation of a YBCO target and a Nb metal foil attached to the surface of the target resulted in epitaxial growth of YBCO films having columnar defects comprised of self-aligned Ba{sub 2}YNbO{sub 6} (BYNO) nanorods parallel to the c-axis of the film. Compared to pure YBCO, YBCO+BYNO films exhibited no T{sub c} reduction as well as superior J{sub c} performance with higher self- and in-field J{sub c} by a factor of 1.5-7 and also exhibited a strong J{sub c} peak for H {parallel} c indicative of strong c-axis correlated flux-pinning.

A compounded rare-earth iron garnet single crystal exhibiting stable Faraday rotation against wavelength and temperature variation in the 1.55 μm band

International Nuclear Information System (INIS)

Xu, Z.C.; Huang, M.; Li Miao

2006-01-01

The Bi, Tb and Yb partially substituted iron garnet bulk single crystals of Tb 3- x - y Yb y Bi x Fe 5 O 12 were grown by using Bi 2 O 3 /B 2 O 3 as flux and accelerated crucible rotation technique for single-crystal growth. Faraday rotation (FR) spectra showed that the specific FR of the (Tb 0.91 Yb 1.38 Bi 0.71 )Fe 5 O 12 crystal under magnetic field at saturation was measured to be about -1617 o /cm at λ=1.55 μm, Faraday rotation wavelength coefficient (FWC, 0.009%/nm) in the wavelength range of 1.50-1.62 μm and Faraday rotation temperature coefficient (FTC, 3.92x10 -5 /K) at λ=1.55 μm were even smaller than that of YIG. It is proven that through combining two types of Bi-substituted rare-earth iron garnets with opposite FWC and FTC signs, the compound rare-earth iron garnets with low FWC and FTC may be obtained due to the compensation effect. The saturation magnetization of (Tb 0.91 Yb 1.38 Bi 0.71 ) Fe 5 O 12 crystal is 0.48x10 6 A/M and is also much smaller than that of YIG. We have found empirically that there is a simple relationship between the FR θ f (x) and Bi content x for Tb 3- x - y Yb y Bi x Fe 5 O 12 , which is given by θ f (x)=(-2759x+400) o /cm

The Mission Accessible Near-Earth Object Survey (MANOS) -- Science Highlights

Science.gov (United States)

Moskovitz, Nicholas; Thirouin, Audrey; Binzel, Richard; Burt, Brian; Christensen, Eric; DeMeo, Francesca; Endicott, Thomas; Hinkle, Mary; Mommert, Michael; Person, Michael; Polishook, David; Siu, Hosea; Thomas, Cristina; Trilling, David; Willman, Mark

2015-08-01

Near-Earth objects (NEOs) are essential to understanding the origin of the Solar System through their compositional links to meteorites. As tracers of other parts of the Solar System they provide insight to more distant populations. Their small sizes and complex dynamical histories make them ideal laboratories for studying ongoing processes of planetary evolution. Knowledge of their physical properties is essential to impact hazard assessment. And the proximity of NEOs to Earth make them favorable targets for a variety of planetary mission scenarios. However, in spite of their importance, only the largest NEOs are well studied and a representative sample of physical properties for sub-km NEOs does not exist.MANOS is a multi-year physical characterization survey, originally awarded survey status by NOAO. MANOS is targeting several hundred mission-accessible, sub-km NEOs across visible and near-infrared wavelengths to provide a comprehensive catalog of physical properties (astrometry, light curves, spectra). Accessing these targets is enabled through classical, queue, and target-of-opportunity observations carried out at 1- to 8-meter class facilities in the northern and southern hemispheres. Our observing strategy is designed to rapidly characterize newly discovered NEOs before they fade beyond observational limits.Early progress from MANOS includes: (1) the de-biased taxonomic distribution of spectral types for NEOs smaller than ~100 meters, (2) the distribution of rotational properties for approximately 100 previously unstudied NEOs, (3) detection of the fastest known rotation period of any minor planet in the Solar System, (4) an investigation of the influence of planetary encounters on the rotational properties of NEOs, (5) dynamical models for the evolution of the overall NEO population over the past 0.5 Myr, and (6) development of a new set of online tools at asteroid.lowell.edu that will enable near realtime public dissemination of our data products while

IMPACT OF η{sub Earth} ON THE CAPABILITIES OF AFFORDABLE SPACE MISSIONS TO DETECT BIOSIGNATURES ON EXTRASOLAR PLANETS

Energy Technology Data Exchange (ETDEWEB)

Léger, Alain [IAS, Univ. Paris-Sud, Orsay (France); Defrère, Denis [Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Malbet, Fabien [UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), UMR 5274, BP 53, F-38041 Grenoble cedex 9 (France); Labadie, Lucas [I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, D-50937 Cologne (Germany); Absil, Olivier, E-mail: Alain.Leger@ias.u-psud.fr [Département d’Astrophysique, Géophysique and Océanographie, Université de Liège, 17 Allée du Six Août, B-4000 Liège (Belgium)

2015-08-01

We present an analytic model to estimate the capabilities of space missions dedicated to the search for biosignatures in the atmosphere of rocky planets located in the habitable zone of nearby stars. Relations between performance and mission parameters, such as mirror diameter, distance to targets, and radius of planets, are obtained. Two types of instruments are considered: coronagraphs observing in the visible, and nulling interferometers in the thermal infrared. Missions considered are: single-pupil coronagraphs with a 2.4 m primary mirror, and formation-flying interferometers with 4 × 0.75 m collecting mirrors. The numbers of accessible planets are calculated as a function of η{sub Earth}. When Kepler gives its final estimation for η{sub Earth}, the model will permit a precise assessment of the potential of each instrument. Based on current estimations, η{sub Earth} = 10% around FGK stars and 50% around M stars, the coronagraph could study in spectroscopy only ∼1.5 relevant planets, and the interferometer ∼14.0. These numbers are obtained under the major hypothesis that the exozodiacal light around the target stars is low enough for each instrument. In both cases, a prior detection of planets is assumed and a target list established. For the long-term future, building both types of spectroscopic instruments, and using them on the same targets, will be the optimal solution because they provide complementary information. But as a first affordable space mission, the interferometer looks the more promising in terms of biosignature harvest.

Enhanced magneto-optical Kerr effect in rare earth substituted nanostructured cobalt ferrite thin film prepared by sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Avazpour, L.; Toroghinejad, M.R. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shokrollahi, H., E-mail: Shokrollahi@sutech.ac.ir [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz 13876-71557 (Iran, Islamic Republic of)

2016-11-30

Highlights: • The nanostructured rare earth doped Co-ferrite thin film was synthesized by the sol–gel method. • The coercivity of as high as 1.8 kOe is achieved for 20% substituted cobalt ferrite. • The average particle diameter of particulate film is decreasing by increasing substitute content. • Kerr spectra of films shifted to higher energies. • Kerr rotation angle increased to 1.65° for 0.1 Eu doped thin film. - Abstract: A series of rare-earth (RE)-doped nanocrystalline Co{sub x} RE{sub (1−x)} Fe{sub 2}O{sub 4} (x = 0, 0.1, 0.2 and RE: Nd, Eu) thin films were prepared on silicon substrates by a sol–gel process, and the influences of different RE{sup 3+} ions on the microstructure, magnetism and polar magneto-optical Kerr effect of the deposited films were investigated. Also this research presents the optimization process of cobalt ferrite thin films deposited via spin coating, by studying their structural and morphological properties at different thicknesses (200, 350 nm) and various heat treatment temperatures 300–850 °C. Nanoparticulate polycrystalline thin film were formed with heat treatment above 400 °C but proper magnetic properties due to well crystallization of the film were achieved at about 650 °C. AFM results indicated that the deposited thin films were crack-free exhibiting a dense nanogranular structure. The root-mean square (RMS) roughness of the thin films was in the range of 0.2–3.2 nm. The results revealed that both of the magnetism and magneto optical Kerr (MOKE) spectra of Co{sub x} RE{sub (1−x)} Fe{sub 2}O{sub 4} films could be mediated by doping with various RE ions. The Curie temperature of substituted samples was lower than pristine cobalt ferrite thin films. In MOKE spectra both dominant peaks were blue shifted with addition of RE ions. For low concentration dopant the inter-valence charge transfer related rotation was enhanced and for higher concentration dopant the crystal field rotation peak was enhanced

Atmospheric dynamics of Earth-like tidally locked aquaplanets

Directory of Open Access Journals (Sweden)

Tapio Schneider

2010-12-01

Full Text Available We present simulations of atmospheres of Earth-like aquaplanets that are tidally locked to their star, that is, planets whose orbital period is equal to the rotation period about their spin axis, so that one side always faces the star and the other side is always dark. Such simulations are of interest in the study of tidally locked terrestrial exoplanets and as illustrations of how planetary rotation and the insolation distribution shape climate. As extreme cases illustrating the effects of slow and rapid rotation, we consider planets with rotation periods equal to one current Earth year and one current Earth day. The dynamics responsible for the surface climate (e.g., winds, temperature, precipitation and the general circulation of the atmosphere are discussed in light of existing theories of atmospheric circulations. For example, as expected from the increasing importance of Coriolis accelerations relative to inertial accelerations as the rotation rate increases, the winds are approximately isotropic and divergent at leading order in the slowly rotating atmosphere but are predominantly zonal and rotational in the rapidly rotating atmosphere. Free-atmospheric horizontal temperature variations in the slowly rotating atmosphere are generally weaker than in the rapidly rotating atmosphere. Interestingly, the surface temperature on the night side of the planets does not fall below ~240 K in either the rapidly or slowly rotating atmosphere; that is, heat transport from the day side to the night side of the planets efficiently reduces temperature contrasts in either case. Rotational waves and eddies shape the distribution of winds, temperature, and precipitation in the rapidly rotating atmosphere; in the slowly rotating atmosphere, these distributions are controlled by simpler divergent circulations. Both the slowly and rapidly rotating atmospheres exhibit equatorial superrotation. Systematic variation of the planetary rotation rate shows that the

Full-Coverage High-Resolution Daily PM(sub 2.5) Estimation using MAIAC AOD in the Yangtze River Delta of China

Science.gov (United States)

Xiao, Qingyang; Wang, Yujie; Chang, Howard H.; Meng, Xia; Geng, Guannan; Lyapustin, Alexei Ivanovich; Liu, Yang

2017-01-01

Satellite aerosol optical depth (AOD) has been used to assess population exposure to fine particulate matter (PM (sub 2.5)). The emerging high-resolution satellite aerosol product, Multi-Angle Implementation of Atmospheric Correction(MAIAC), provides a valuable opportunity to characterize local-scale PM(sub 2.5) at 1-km resolution. However, non-random missing AOD due to cloud snow cover or high surface reflectance makes this task challenging. Previous studies filled the data gap by spatially interpolating neighboring PM(sub 2.5) measurements or predictions. This strategy ignored the effect of cloud cover on aerosol loadings and has been shown to exhibit poor performance when monitoring stations are sparse or when there is seasonal large-scale missngness. Using the Yangtze River Delta of China as an example, we present a Multiple Imputation (MI) method that combines the MAIAC high-resolution satellite retrievals with chemical transport model (CTM) simulations to fill missing AOD. A two-stage statistical model driven by gap-filled AOD, meteorology and land use information was then fitted to estimate daily ground PM(sub 2.5) concentrations in 2013 and 2014 at 1 km resolution with complete coverage in space and time. The daily MI models have an average R(exp 2) of 0.77, with an inter-quartile range of 0.71 to 0.82 across days. The overall Ml model 10-fold cross-validation R(exp 2) (root mean square error) were 0.81 (25 gm(exp 3)) and 0.73 (18 gm(exp 3)) for year 2013 and 2014, respectively. Predictions with only observational AOD or only imputed AOD showed similar accuracy.Comparing with previous gap-filling methods, our MI method presented in this study performed bette rwith higher coverage, higher accuracy, and the ability to fill missing PM(sub 2.5) predictions without ground PM(sub 2.5) measurements. This method can provide reliable PM(sub 2.5)predictions with complete coverage that can reduce biasin exposure assessment in air pollution and health studies.

Amorphization and crystallization of Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) alloys during mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Wang Yan [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, 73 Jingshi Road, Jinan 250061 (China); School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China); Chen Xiuxiu [School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China); Geng Haoran [School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China)], E-mail: mse_wangy@ujn.edu.cn; Yang Zhongxi [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, 73 Jingshi Road, Jinan 250061 (China); School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China)

2009-04-17

In the present paper, the effect of Nb and different rotation speeds on the amorphization and crystallization of Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) alloys during mechanical alloying has been investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The results show that the minor addition of Nb can shorten the start time of the amorphization reaction, improve the glass forming ability of Zr-Cu alloys, but cannot promote the formation of a single amorphous phase at a lower rotation speed of 200 rpm. The glass forming ability of the Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) alloys increases with increasing Nb additions. At a higher rotation speed of 350 rpm, a single amorphous phase of Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) can be successfully fabricated. Moreover, the Nb addition into Zr-Cu alloys can accelerate the amorphization process and improve the stability of the amorphous phase against the mechanically induced crystallization. Furthermore, the amorphous Zr{sub 66.7}Cu{sub 33.3} phase gradually transforms into a metastable fcc-Zr{sub 2}Cu phase with increasing milling time.

Rare earth ion controlled crystallization of mica glass-ceramics

Energy Technology Data Exchange (ETDEWEB)

Garai, Mrinmoy; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in

2016-09-05

In understanding the effects of rare earth ions to control the crystallization and microstructure of alkaline boroaluminosilicate system, the CeO{sub 2}, Nd{sub 2}O{sub 3}, Sm{sub 2}O{sub 3} and Gd{sub 2}O{sub 3} doped K{sub 2}O−MgO−B{sub 2}O{sub 3}−Al{sub 2}O{sub 3}−SiO{sub 2}−F glasses were synthesized by melt-quenching at 1550 °C. Higher density (2.82–3.06 g cm{sup −3}) and thermal stability (glass phase) is experiential on addition of rare earth content, which also affects in increasing the glass transition temperature (T{sub g}) and crystallization temperature (T{sub c}). Decrease of thermal expansion in glasses with rare earth ion content is maintained by the stabilization of glass matrix owing to their large cationic field strength. A significant change in the non-isothermal DSC thermogram observed at 750–1050 °C is attributed to fluorophlogopite crystallization. Opaque glass-ceramics were prepared from such glasses by single step heat-treatment at 1050 °C; and the predominant crystalline phases are identified as fluorophlogopite mica, KMg{sub 3}(AlSi{sub 3}O{sub 10})F{sub 2} by XRD and EDX analysis. The compact glass-ceramic microstructure by the agglomeration of fluorophlogopite mica crystallites (crystal size ∼ 100–500 nm, FESEM) is achieved in attendance of rare earth ion; and such microstructure controlled the variation of density, thermal expansion and microhardness value. Higher thermal expansion (11.11–14.08 × 10{sup −6}/K at 50–800 °C and 50–900 °C) of such glass-ceramics approve that these rare earth containing glasses can be useful for high temperature vacuum sealing application with metal or solid electrolyte. The increase of Vickers microhardness (5.27–5.61 GPa) in attendance of rare earth ions is attributed to the compact crystallinity of fluorophlogopite mica glass-ceramic microstructure. - Highlights: • Synthesis of rare earth oxide doped alkaline boroaluminosilicate glasses. • Development of opaque

Tully-Fisher relation, galactic rotation curves and dissipative mirror dark matter

Energy Technology Data Exchange (ETDEWEB)

Foot, R., E-mail: rfoot@unimelb.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, University of Melbourne, Victoria 3010 Australia (Australia)

2014-12-01

If dark matter is dissipative then the distribution of dark matter within galactic halos can be governed by dissipation, heating and hydrostatic equilibrium. Previous work has shown that a specific model, in the framework of mirror dark matter, can explain several empirical galactic scaling relations. It is shown here that this dynamical halo model implies a quasi-isothermal dark matter density, ρ(r) ≅ ρ{sub 0}r{sub 0}{sup 2}/(r{sup 2}+r{sub 0}{sup 2}), where the core radius, r{sub 0}, scales with disk scale length, r{sub D}, via r{sub 0}/kpc ≈ 1.4(r{sub D}/kpc). Additionally, the product ρ{sub 0}r{sub 0} is roughly constant, i.e. independent of galaxy size (the constant is set by the parameters of the model). The derived dark matter density profile implies that the galactic rotation velocity satisfies the Tully-Fisher relation, L{sub B}∝v{sup 3}{sub max}, where v{sub max} is the maximal rotational velocity. Examples of rotation curves resulting from this dynamics are given.

Sub-keV secondary ion mass spectrometry depth profiling: comparison of sample rotation and oxygen flooding

International Nuclear Information System (INIS)

Liu, R.; Wee, A.T.S.

2004-01-01

Following the increasingly stringent requirements in the characterization of sub-micron IC devices, an understanding of the various factors affecting ultra shallow depth profiling in secondary ion mass spectrometry (SIMS) has become crucial. Achieving high depth resolution (of the order of 1 nm) is critical in the semiconductor industry today, and various methods have been developed to optimize depth resolution. In this paper, we will discuss ultra shallow SIMS depth profiling using B and Ge delta-doped Si samples using low energy 0.5 keV O 2 + primary beams. The relationship between depth resolution of the delta layers and surface topography measured by atomic force microscopy (AFM) is studied. The effect of oxygen flooding and sample rotation, used to suppress surface roughening is also investigated. Oxygen flooding was found to effectively suppress roughening and gives the best depth resolution for B, but sample rotation gives the best resolution for Ge. Possible mechanisms for this are discussed

Accounting for the Effect of Earth's Rotation in Magnetotelluric Inference

Science.gov (United States)

Riegert, D. L.; Thomson, D. J.

2017-12-01

The study of geomagnetism has been documented as far back as 1722 when the watchmaker G. Graham constructed a more sensitive compass and showed that the variations in geomagnetic direction varied with an irregular daily pattern. Increased interest in geomagnetism in geomagnetism began at the end of the 19th century (Lamb, Schuster, Chapman, and Price). The Magnetotelluric Method was first introduced in the 1950's (Cagniard and Tikhonov), and, at its core, is simply a regression problem. The result of this method is a transfer function estimate which describes the earth's response to magnetic field variations. This estimate can then be used to infer the earth's subsurface structure; useful for applications such as natural resource exploration. The statistical problem of estimating a transfer function between geomagnetic and induced current measurements has evolved since the 1950's due to a variety of problems: non-stationarity, outliers, and violation of Gaussian assumptions. To address some of these issues, robust regression methods (Chave and Thomson, 2004) and the remote reference method (Gambel, 1979) have been proposed and used. The current method seems to provide reasonable estimates, but still requires a large amount of data. Using the multitaper method of spectral analysis (Thomson, 1982), taking long (greater than 4 months) blocks of geomagnetic data, and concentrating on frequencies below 1000 microhertz to avoid ultraviolet effects, one finds that:1) the cross-spectra are dominated by many offset frequencies including plus and minus 1 and 2 cycles per day;2) the coherence at these offset frequencies is often stronger than at zero offset;3) there are strong couplings from the "quasi two-day" cycle;4) frequencines are usually not symmetric;5) the spectra are dominated by the normal modes of the Sun. This talk will discuss the method of incorporating these observations into the transfer function estimation model, some of the difficulties that arose, their

Book Review: Precession, Nutation, and Wobble of the Earth

Science.gov (United States)

Sterken, Christiaan; Dehant, V.; Mathews, P. M.

2016-10-01

This great book describes and explains observational and computational aspects of three apparently tiny changes in the Earth's motion and orientation, viz., precession, nutation, and wobble. The three introductory chapters of this book present fundamental definitions, elementary geodetic theory, and celestial/terrestrial reference systems - including transformations between reference frames. The next chapter on observational techniques describes the principle of accurate measurements of the orientation of the Earth's axis, as obtained from measurements of extra-galactic radio sources using Very Long Baseline Interferometry and GPS observations. Chapter 5 handles precession and nutation of the rigid Earth (i.e., a celestial body that cannot, by definition, deform) and the subsequent chapter takes deformation into consideration, viz., the effect of a centrifugal force caused by a constant-rate rotation that causes the Earth's shape and structure to become ellipsoidal. Deformations caused by external solar-system bodies are discussed in terms of deformability parameters. The next three chapters handle additional complex deviations: non-rigid Earth and more general Earth models, anelastic Earth parameters, and the effects of the fluid layers (i.e., ocean and atmosphere) on Earth rotation. Chapter 10 complements Chapter 7 with refinements that take into account diverse small effects such as the effect of a thermal conductive layer at the top of the core, Core Mantle and Inner Boundary coupling effects on nutation, electromagnetic coupling, and so-called topographic coupling. Chapter 11 covers comparison of observation and theory, and tells us that the present-date precision of the nutation theory is at the level of milliarcseconds in the time domain, and of a tenth of a microsecond in the frequency domain (with some exceptions). This chapter is followed by a 25-page chapter of definitions of equator, equinox, celestial intermediate pole and origin, stellar angle

Assessment of the effect of three-dimensional mantle density heterogeneity on Earth rotation in tidal frequencies

Directory of Open Access Journals (Sweden)

Lanbo Liu

2016-11-01

Full Text Available In this paper, we report the assessment of the effect of the three-dimensional (3D density heterogeneity in the mantle on Earth orientation parameters (EOP (i.e., the polar motion, or PM, and the length of day, or LOD in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6L8 and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the preliminary reference earth model (PREM. Using this approach the effects of the heterogeneous mantle density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal are estimated in both PM and LOD. When compared with mass or density perturbations originated on the Earth's surface such as the oceanic and barometric changes, the heterogeneous mantle contributes less than 10% of the total variation in PM and LOD in tidal frequencies. However, this is the gap that has not been explained to close the gap of the observation and modeling in PM and LOD. By computing the PM and LOD caused by 3D heterogeneity of the mantle during the period of continuous space geodetic measurement campaigns (e.g., CONT94 and the contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon in the same period, we got the lump-sum values of PM and LOD. The computed total effects and the observed PM and LOD are generally agree with each other. In another word, the difference of the observed PM and LOD and the model only considering ocean tides, at all tidal frequencies (long periods, diurnals, and semidiurnals contains the contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle density heterogeneity effect on torque-free Earth rotation may provide useful constraints to construct the reference earth model (REM, which is the next major objective in global

Magnetic, dielectric and microwave absorption properties of rare earth doped Ni–Co and Ni–Co–Zn spinel ferrites

Energy Technology Data Exchange (ETDEWEB)

Stergiou, Charalampos, E-mail: stergiou@cperi.certh.gr

2017-03-15

In this article we analyze the electromagnetic properties of rare earth substituted Ni–Co and Ni–Co–Zn cubic ferrites in the microwave band, along with their performance as microwave absorbing materials. Ceramic samples with compositions Ni{sub 0.5}Co{sub 0.5}Fe{sub 2−x}R{sub x}O{sub 4} and Ni{sub 0.25}Co{sub 0.5}Zn{sub 0.25}Fe{sub 2−x}R{sub x}O{sub 4} (R=Y and La, x=0, 0.02), fabricated with the solid state reaction method, were characterized with regard to the complex permeability μ*(f) and permittivity ε*(f) up to 20 GHz. The rare earth substitutions basically affect the microwave μ*(f) spectra and the dynamic magnetization mechanisms of domain wall motion and magnetization rotation. Key parameters for this effect are the reduced magnetocrystalline anisotropy and the created crystal inhomogeneities. Moreover, permittivity is increased with the Y and La content, due to the enhancement of the dielectric orientation polarization. Regarding the electromagnetic wave attenuation, the prepared ferrites exhibit narrowband return losses (RL) by virtue of the cancellation of multiple reflections, when their thickness equals an odd multiple of quarter-wavelength. Interestingly, the zero-reflection conditions are satisfied in the vicinity of the ferromagnetic resonance. As the rare earth doping shifts this mechanism to lower frequencies, loss peaks with RL>46 dB occur at 4.1 GHz and 5 GHz for Y and La-doped Ni–Co–Zn spinels, whereas peaks with RL>40 dB appear at 18 GHz and 19 GHz for Y and La-doped Ni–Co spinels, respectively. The presented experimental findings underline the potential of cubic ferrites with high Co concentration in the suppression of electromagnetic reflections well above the 1 GHz region. - Highlights: • Due to cation distribution, magnetic anisotropy drops in Y and La doped samples. • Microwave permeability spectra shift to lower frequencies with rare earth doping. • Permittivity is increased due to crystal modifications

Electrical resistivity of YbRh{sub 2}Si{sub 2} and EuT{sub 2}Ge{sub 2} (T=Co,Cu) at extreme conditions of pressure and temperature

Energy Technology Data Exchange (ETDEWEB)

Dionicio, G.A.

2006-07-01

This investigation addresses the effect that pressure, p, and temperature, T, have on 4f states of the rare-earth elements in the isostructural YbRh{sub 2}Si{sub 2}, EuCo{sub 2}Ge{sub 2}, and EuCu{sub 2}Ge{sub 2} compounds. Upon applying pressure the volume of the unit cell reduces, enforcing either the enhancement of the hybridization of the 4f localized electrons with the ligand or a change in the valence state of the rare-earth ions. Here, we probe the effect of a pressure-induced lattice contraction on these system by means of electrical-resistivity measurements, {rho}(T), from room temperature down to 100 mK. (orig.)

Enhanced pinning in mixed rare earth-123 films

Science.gov (United States)

Driscoll, Judith L [Los Alamos, NM; Foltyn, Stephen R [Los Alamos, NM

2009-06-16

An superconductive article and method of forming such an article is disclosed, the article including a substrate and a layer of a rare earth barium cuprate film upon the substrate, the rare earth barium cuprate film including two or more rare earth metals capable of yielding a superconductive composition where ion size variance between the two or more rare earth metals is characterized as greater than zero and less than about 10.times.10.sup.-4, and the rare earth barium cuprate film including two or more rare earth metals is further characterized as having an enhanced critical current density in comparison to a standard YBa.sub.2Cu.sub.3O.sub.y composition under identical testing conditions.

Synthesis, crystal structure, and magnetic properties of novel 2D kagome materials RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} (RE = La, Pr, Sm, Eu, Tb, Ho): Comparison to RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14} family

Energy Technology Data Exchange (ETDEWEB)

Sanders, M.B.; Baroudi, K.M.; Krizan, J.W.; Mukadam, O.A.; Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ (United States)

2016-10-15

The crystal structures and magnetic properties of RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} (RE = La, Pr, Sm, Eu, Tb, Ho) with a perfect kagome lattice are presented and compared to RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14}. Rietveld structure refinements were performed using X-ray diffraction data, indicating that the layered compounds are fully structurally ordered. The compounds crystallize in a rhombohedral supercell of the cubic pyrochlore structure, in the space group R-3m. Magnetic susceptibility measurements show no signs of magnetic ordering above 2 K. The RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} family is similar to that of RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14}; however, the series reported here features a fully ordered distribution of cations in both the nonmagnetic antimony and magnetic rare earth kagome lattices. Unlike the offsite disorder that Zn{sup 2+} experiences in RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14}, the magnesium sites in RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} are completely ordered. Here we compare the magnetic properties in both series of kagome compounds to determine how significant Zn{sup 2+}'s positional ordering is within this structure type. The compounds reported here appear to be relatively defect-free and are therefore model systems for investigating magnetic frustration on an ideal 2D rare earth kagome lattice. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Table-top rotating turbulence : an experimental insight through Particle Tracking

NARCIS (Netherlands)

Castello, Del L.

2010-01-01

The influence of the Earth background rotation on oceanic and atmospheric currents, as well as the effects of a rapid rotation on the flow inside industrial machineries like mixers, turbines, and compressors, are only the most typical examples of fluid flows affected by rotation. Despite the

Origin of the Earth's Electromagnetic Field Based on the Pulsating Mantle Hypothesis (PMH)

Science.gov (United States)

Gholibeigian, Hassan

2017-11-01

In PMH, the Earth's Inner Core's Dislocation (ICD) and Outer Core's Bulge (OCB) phenomena are generated by unbalanced gravitational fields of the Sun and Moon on the Earth. Distance between the Earth's center and inner core's center varies permanently in magnitude and direction inside two hemispheres. Geometrical loci of the inner core's center has the shape of back and force spiral cone in each hemisphere. In other words, the inner core is rotating fast in the outer core inverse of the Earth's rotation a round per day. This mechanism speed up the processes inside the core and generates a Large Scale Forced Convection System (LSFCS) inverse of the Earth's rotation in the core. The LSFCS is the origin of the Earth's electromagnetic field. The LSFCS generates huge mass transfer and momentum of inertia inside the Earth too. The inner core's axis which is the Earth's electromagnetic axis doesn't cross the Earth's geophysical axis and rotates around it per day. The mechanism of this LSFCS has diurnal, monthly and yearly cycles. These cycles are sources of the Earth's electromagnetic field variability. Direction of the variable Earth's magnetic field lines from the South Pole (hemisphere) to the sky and 146 seconds/years apparent solar day length variations can be two observable factors for this mechanism. This dynamic system may occurred inside the other planets like the Sun and the Jupiter.

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

Science.gov (United States)

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.

Study of CeO{sub x}, PrO{sub x}, and Ce{sub x}Pr{sub 1-x}O{sub 2-{delta}} films on Si(111) by means of high-energetic X-ray photoelectron spectroscopy; Untersuchung von CeO{sub x}-, PrO{sub x}- und Ce{sub x}Pr{sub 1-x}O{sub 2-{delta}}- Filmen auf Si (111) mittels hochenergetischer Roentgen-Photoelektronenspektroskopie

Energy Technology Data Exchange (ETDEWEB)

Allahgholi, Aschkan

2013-03-15

The intention of this work is to shed light on two much discussed topics in the study of rare earth oxides (REO) by hard x-ray photoelectron spectroscopy (HAXPES): (i) Due to the complex spectral shape of the Ce3d region, there have been many discussions on proper approaches to determine the concentration of Ce{sup 3+} and Ce{sup 4+} species in CeO{sub x} over the last decades. (ii) Recently, the true electron structure of rare earth oxides gained new attention, since ab initio calculations showed the necessity of considering additional inter atomic charge transfer to Ce5d levels. Using HAXPES and resonant HAXPES, the question of the true electronic structure of rare earth oxides is approached from the experimental side. As a third topic, the obtained results for cerium oxide and praseodymium oxide are applied in order to investigate the plasma oxidized mixed oxide Ce{sub x}Pr{sub 1-x}O{sub 2-{delta}} grown on Si(111) during thermal reduction. (orig.)

WAVE TECTONICS OF THE EARTH

Directory of Open Access Journals (Sweden)

Tatiana Yu. Tveretinova

2010-01-01

Full Text Available In the Earth's lithosphere, wavy alternation of positive and negative heterochronous structures is revealed; such structures are variable in ranks and separated by vergence zones of fractures and folds. In the vertical profile of the lithosphere, alternating are layers characterized by relatively plastic or fragile rheological properties and distinguished by different states of stress. During the Earth’s evolution, epochs of compression and extension are cyclically repeated, including planetary-scale phenomena which are manifested by fluctuating changes of the planet’s volume. Migration of geological and geophysical (geodynamic processes takes place at the Earth's surface and in its interior. The concept of the wave structure and evolution of the Earth's lithosphere provides explanations to the abovementioned regularities. Wavy nature of tectonic structures of the lithosphere, the cyclic recurrence of migration and geological processes in space and time can be described in terms of the multiple-order wave geodynamics of the Earth's lithosphere that refers to periodical variations of the state of stress. Effects of structure-forming tectonic forces are determined by «interference» of tangential and radial stresses of the Earth. The tangential stresses, which occur primarily due to the rotational regime of the planet, cause transformations of the Earth’s shape, redistributions of its substance in depths, the westward drift of the rock mass in its upper levels, and changes of structural deformation plans. The radial stresses, which are largely impacted by gravity, determine the gravitational differentiation of the substance, vertical flattening and sub-horizontal flow of the rock masses, and associated fold-rupture deformation. Under the uniform momentum geodynamic concept proposed by [Vikulin, Tveritinova, 2004, 2005, 2007, 2008], it is possible to provide consistent descriptions of seismic and volcanic, tectonic and geological processes

[Correlation of fine structures of distributions of amplitudes of a photomultiplier dark current fluctuations with the Earth rotations about its axis].

Science.gov (United States)

Fedorov, M V; Belousov, L V; Voeĭkov, V L; Zenchenko, K I; Zenchenko, T A; Konradov, A A; Shnol', S E

2001-01-01

The fine structures of distributions of photomultiplier dark current fluctuations measured in two laboratories 2000 km distant from other: in the international Institute of Biophysics (Neuss, Germany) and in the Moscow State University (Moscow, Russia) were compared. It is shown that similar forms of appropriate histograms are apparently more often realized at both locations at the same local time. This confirms the previous conclusion that the fine structure of distributions correlates with rotation of the Earth about its axis.

When the Earth's Inner Core Shuffles

Science.gov (United States)

Tkalcic, H.; Young, M. K.; Bodin, T.; Ngo, S.; Sambridge, M.

2011-12-01

Shuffling is a tribal dance recently adapted by teenagers as a street dance. In one of the most popular moves, the so-called "Running Man", a stomp forward on one foot, shifted without being lifted from the ground, is followed by a change of position backwards on the same foot. Here, we present strong observational evidence from a newly observed collection of earthquake doublets that the Earth's inner core "shuffles" exhibiting both prograde and retrograde rotation in the reference frame of the mantle. This discovery is significant on several levels. First, the observed pattern consists of intermittent intervals of quasi-locked and differentially rotating inner core with respect to the Earth's mantle. This means that the angular alignment of the inner core and mantle oscillates in time over the past five decades. Jolting temporal changes are revealed, indicating that during the excursions from the quasi-locked state, the Earth's inner core can rotate both faster and slower than the rest of the planet, thus exhibiting both eastward and westward rotation. According to our results, a short time interval (on the order of one to two years) is needed for the inner core to accelerate to a differential rotation rate of several degrees per year, and typically a slightly longer time is needed to decelerate down to a negligibly small differential rotation rate. These time scales are in agreement with experimental spin-up times obtained when the magnetic torque alone is used to accelerate the inner core. Second, when we integrate the rotation rate over different time intervals, it is possible to explain discrepancies between the body wave and normal modes results for the rate of the inner core differential rotation found by previous authors. We show that the integrated shift in angular alignment and average rotation rates (previously determined to be constant) in normal mode studies are much smaller that those for the body waves. The repeating earthquakes from the South

An Expectation of a backbending for N> 98 of a rare earth nuclei

Energy Technology Data Exchange (ETDEWEB)

Salah, M M [Physics Dept., Faculty of Science, Minia University, (Egypt); El-Elgebaly, H [Physics Dept., Faculty of Science, Cairo University, Cairo (Egypt)

1997-12-31

The backbending of three neighboring earth nuclei [Er-Yb-Hf] with their isotopes has been studied through the cubic polynomial (CP) theoretical model in addition to [Ex vs. I (I+I)] and [0 vs.{sub 2}] plots, at high energy angular momentum in nuclear rotational bands according to the values of R 4. Also the rotational nuclei are divided into soft and hard rotors by studying the softness S. We expected that there may be a backbending for nuclei of N> 98, but with a High angular momentum, which were not expected before by studying the effect of (I+I) at the critical spin of a backbending. The work includes study of the effective moment of inertia 0eff for these nuclei, and the theoretical treatment to reduce the error in energy calculation of (CP) model. 5 figs., 1 tab.

Apparent molar volumes and apparent molar heat capacities of Pr(NO{sub 3}){sub 3}(aq), Gd(NO{sub 3}){sub 3}(aq), Ho(NO{sub 3}){sub 3}(aq), and Y(NO{sub 3}){sub 3}(aq) at T (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa

Energy Technology Data Exchange (ETDEWEB)

Hakin, Andrew W. [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada)]. E-mail: hakin@uleth.ca; Liu Jinlian [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Erickson, Kristy [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Munoz, Julie-Vanessa [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Rard, Joseph A. [Energy and Environment Directorate, Lawrence Livermore National Laboratory, University of California, Livermore, CA 94550 (United States)

2005-02-01

Relative densities and relative massic heat capacities have been measured for acidified solutions of Y(NO{sub 3}){sub 3}(aq), Pr(NO{sub 3}){sub 3}(aq), and Gd(NO{sub 3}){sub 3}(aq) at T = (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa. In addition, relative densities and massic heat capacities have been measured at the same temperatures and pressure for Y(NO{sub 3}){sub 3}(aq) and Ho(NO{sub 3}){sub 3}(aq) solutions without excess acid (n.b. measurements at T = 328.15 K for Ho(NO{sub 3}){sub 3}(aq) were not performed due to the limited volume of solution available). Apparent molar volumes and apparent molar heat capacities for the aqueous salt solutions have been calculated from the experimental apparent molar properties of the acidified solutions using Young's rule, whereas the apparent molar properties of the solutions without excess acid were calculated directly from the measured densities and massic heat capacities. The two sets of data for the Y(NO{sub 3}){sub 3}(aq) systems provide a check of the internal consistency of the Young's rule approach we have utilised. The concentration dependences of the apparent molar volumes and heat capacities of the aqueous salt solutions have been modelled at each investigated temperature using the Pitzer ion interaction equations to yield apparent molar properties at infinite dilution. Complex formation within the aqueous rare earth nitrate systems is discussed qualitatively by probing the concentration dependence of apparent molar volumes and heat capacities. In spite of the complex formation in the aqueous rare earth nitrate systems, there is a high degree of self-consistency between the apparent molar volumes and heat capacities at infinite dilution reported in this manuscript and those previously reported for aqueous rare earth perchlorates.

Chronic daily headaches

Directory of Open Access Journals (Sweden)

Fayyaz Ahmed

2012-01-01

Full Text Available Chronic Daily Headache is a descriptive term that includes disorders with headaches on more days than not and affects 4% of the general population. The condition has a debilitating effect on individuals and society through direct cost to healthcare and indirectly to the economy in general. To successfully manage chronic daily headache syndromes it is important to exclude secondary causes with comprehensive history and relevant investigations; identify risk factors that predict its development and recognise its sub-types to appropriately manage the condition. Chronic migraine, chronic tension-type headache, new daily persistent headache and medication overuse headache accounts for the vast majority of chronic daily headaches. The scope of this article is to review the primary headache disorders. Secondary headaches are not discussed except medication overuse headache that often accompanies primary headache disorders. The article critically reviews the literature on the current understanding of daily headache disorders focusing in particular on recent developments in the treatment of frequent headaches.