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Sample records for solar rotation rate

  1. Contrasting the solar rotation rate of cycles 23 and 24

    International Nuclear Information System (INIS)

    Antia, H M; Basu, Sarbani

    2013-01-01

    The minimum between solar cycles 23 and 24 was quite unusual compared with other minima for which detailed data are available and this pointed to the possibility that cycle 24 will be unusual. Cycle 24 is almost at its maximum now and we take this opportunity to compare and contrast the solar rotation rate and zonal flows between the two cycles. We find that the rotation rate during cycle 24 is slightly lower than that during cycle 23. Additionally we find that the poleward branch of the zonal flow that is believed to be the harbinger of the next solar cycle is very week in cycle 24.

  2. ROTATION RATE DIFFERENCES OF POSITIVE AND NEGATIVE SOLAR MAGNETIC FIELDS BETWEEN ±60° LATITUDES

    Energy Technology Data Exchange (ETDEWEB)

    Shi, X. J.; Xie, J. L., E-mail: shixiangjun@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

    2015-04-15

    Based on a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields from Carrington Rotations Nos. 1625 to 2135 (from 1975 February to 2013 March), the sidereal rotation rates of the positive and negative magnetic fields in the latitude range of ±60° are obtained, and the rotation rate differences between them are investigated. The time–latitude distribution of the rate differences is shown, which looks like a butterfly diagram at the low and middle latitudes. For comparison, the time–latitude distribution of the longitudinally averaged photospheric magnetic fields is shown. We conclude that the magnetic fields having the same polarity as the leading sunspots at a given hemisphere rotate faster than those exhibiting the opposite polarity at low and middle latitudes. However, at higher latitudes, the magnetic fields having the same polarity as the leading sunspots at a given hemisphere do not always rotate faster than those with the opposite polarity. Furthermore, the relationship between the rotation rate differences and solar magnetic fields is studied through a correlation analysis. Our result shows that the correlation coefficients between them reach maximum values at 13° (14°) latitude in the northern (southern) hemisphere, and change sign at 28° latitude in both hemispheres, then reach their minimum values at 58° (53°) latitude in the northern (southern) hemisphere.

  3. Recurring coronal holes and their rotation rates during the solar cycles 22-24

    Science.gov (United States)

    Prabhu, K.; Ravindra, B.; Hegde, Manjunath; Doddamani, Vijayakumar H.

    2018-05-01

    Coronal holes (CHs) play a significant role in making the Earth geo-magnetically active during the declining and minimum phases of the solar cycle. In this study, we analysed the evolutionary characteristics of the Recurring CHs from the year 1992 to 2016. The extended minimum of Solar Cycle 23 shows unusual characteristics in the number of persistent coronal holes in the mid- and low-latitude regions of the Sun. Carrington rotation maps of He 10830 Å and EUV 195 Å observations are used to identify the Coronal holes. The latitude distribution of the RCHs shows that most of them are appeared between ± 20° latitudes. In this period, more number of recurring coronal holes appeared in and around 100° and 200° Carrington longitudes. The large sized coronal holes lived for shorter period and they appeared close to the equator. From the area distribution over the latitude considered, it shows that more number of recurring coronal holes with area <10^{21} cm2 appeared in the southern latitude close to the equator. The rotation rates calculated from the RCHs appeared between ± 60° latitude shows rigid body characteristics. The derived rotational profiles of the coronal holes show that they have anchored to a depth well below the tachocline of the interior, and compares well with the helioseismology results.

  4. Asteroid rotation rates

    International Nuclear Information System (INIS)

    Binzel, R.P.; Farinella, P.

    1989-01-01

    Within the last decade the data base of asteroid rotation parameters (rotation rates and lightcurve amplitudes) has become sufficiently large to identify some definite rends and properties which can help us to interpret asteroid collisional evolution. Many significant correlations are found between rotation parameters and diameter, with distinct changes occurring near 125 km. The size range, which is also the diameter above which self-gravity may become important, perhaps represents a division between surviving primordial asteroids and collisional fragments. A Maxwellian is able to fit the observed rotation rate distributions of asteroids with D>125 km, implying that their rotation rates may be determined by collisional evolution. Asteroids with D<125 km show an excess of slow rotators and their non-Maxwellian distributions suggests that their rotation rates are more strongly influenced by other processes, such as the distribution resulting from their formation in catastrophic disruption events. Other correlations observed in the data set include different mean rotation rates for C, S and M type asteroids implying that their surface spectra are indicative of bulk properties

  5. INTERNAL-CYCLE VARIATION OF SOLAR DIFFERENTIAL ROTATION

    International Nuclear Information System (INIS)

    Li, K. J.; Xie, J. L.; Shi, X. J.

    2013-01-01

    The latitudinal distributions of the yearly mean rotation rates measured by Suzuki in 1998 and 2012 and Pulkkinen and Tuominen in 1998 are utilized to investigate internal-cycle variation of solar differential rotation. The rotation rate at the solar equator seems to have decreased since cycle 10 onward. The coefficient B of solar differential rotation, which represents the latitudinal gradient of rotation, is found to be smaller in the several years after the minimum of a solar cycle than in the several years after the maximum time of the cycle, and it peaks several years after the maximum time of the solar cycle. The internal-cycle variation of the solar rotation rates looks similar in profile to that of the coefficient B. A new explanation is proposed to address such a solar-cycle-related variation of the solar rotation rates. Weak magnetic fields may more effectively reflect differentiation at low latitudes with high rotation rates than at high latitudes with low rotation rates, and strong magnetic fields may more effectively repress differentiation at relatively low latitudes than at high latitudes. The internal-cycle variation is inferred as the result of both the latitudinal migration of the surface torsional pattern and the repression of strong magnetic activity in differentiation.

  6. Rotation of the Solar Equator

    Science.gov (United States)

    Kotov, V. A.

    2017-06-01

    Regular measurements of the general magnetic field of the Sun, performed over about half a century at the Crimean Astrophysical Observatory, the J. Wilcox Solar Observatory, and five other observatories, are considered in detail for the time 1968 - 2016. They include more than twenty-six thousand daily values of the mean line-of-sight field strength of the visible solar hemisphere. On the basis of these values, the equatorial rotation period of the Sun is found to be 26.926(9) d (synodic). It is shown that its half-value coincides within error limits with both the main period of the magnetic four-sector structure, 13.4577(25) d, and the best-commensurate period of the slow motions of the major solar system bodies, 13.479(22) d (sidereal). The probability that the two periods coincide by chance is estimated to be about 10^{-7}. The true origin of this odd resonance is unknown.

  7. The solar house that rotates

    International Nuclear Information System (INIS)

    Miloni, R.P.

    2001-01-01

    This article describes an innovative solar building in Weiz, Austria, that uses passive solar technologies, photovoltaics and a ground-coupled heat pump to cover its minimal energy requirements. The house, which follows the sun by rotating around its central axis, is described in detail, including its climatic design and its 'plus-energy' concept. Details are also given on the materials used in the house's construction and the functioning of its thermal insulation. The various operating modes of the house from the systems point of view are described for differing seasons and climatic extremes. Marketing aspects for this standardised house, featuring personal-computer-based on-line definition of facade cladding, fittings, photovoltaic power, furnishings etc. and real-time rendering of the house are also discussed

  8. The Faraday rotation experiment. [solar corona

    Science.gov (United States)

    Volland, H.; Levy, G. S.; Bird, M. K.; Stelzried, C. T.; Seidel, B. L.

    1984-01-01

    The magnetized plasma of the solar corona was remotely sounded using the Faraday rotation effect. The solar magnetic field together with the electrons of the coronal plasma cause a measurable Faraday rotation effect, since the radio waves of Helios are linearly polarized. The measurement is performed at the ground stations. Alfven waves traveling from the Sun's surface through the corona into interplanetary space are observed. Helios 2 signals penetrating through a region where coronal mass is ejected show wavelike structures.

  9. Solar polar rotation and its effect on heliospheric neutral fluxes

    Science.gov (United States)

    Sokol, J. M.; Grzedzielski, S.; Bzowski, M.

    2016-12-01

    The magnetic field in the solar polar corona exhibit a regular "ray-like" structure associated with large polar coronal holes during solar minimum. The solar rotation twists the magnetic field lines of the expanding fast solar wind over the poles. The twist induces a toroidal component of the polar magnetic field which results in magnetic forces directed towards the rotation axis. That is tantamount to a (weak) zeta pinch, known also in other astrophysical contexts (e.g. AGN plasmas). The pinch compresses the polar solar corona plasma and a cone-like enhancement in the solar wind density forms along the rotation axis. Though the effect is likely very dynamic, a time independent description is used here to get an order-of-magnitude estimate. The weak pinch is treated as a 1st order perturbation to the zero-order radial flow. The obtained density enhancement may affect the near and far heliosphere, modifying the charge-exchange and electron impact ionization rates of neutral atoms in interplanetary space. The charge exchange is the most effective ionization process for hydrogen and oxygen atoms, and electron impact ionization is a significant loss reaction for the helium atoms at close distances to the Sun. The change in the polar density due to the solar polar corona rotation could be of importance in the inner heliosphere for low energy atoms. We will present the influence of this effect on interstellar neutral gas distribution and H ENA fluxes observed by IBEX.

  10. 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

  11. A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups

    Science.gov (United States)

    Ruždjak, Domagoj; Brajša, Roman; Sudar, Davor; Skokić, Ivica; Poljančić Beljan, Ivana

    2017-12-01

    The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differential-rotation parameters A and B. These differential-rotation parameters were compared with the solar-activity level. We found that the Sun rotates more differentially at the minimum than at the maximum of activity during the epoch 1977 - 2016. An inverse correlation between equatorial rotation and solar activity was found using the recently revised sunspot number. The secular decrease of the equatorial rotation rate that accompanies the increase in activity stopped in the last part of the twentieth century. It was noted that when a significant peak in equatorial rotation velocity is observed during activity minimum, the next maximum is weaker than the previous one.

  12. SOLAR ROTATION EFFECTS ON THE HELIOSHEATH FLOW NEAR SOLAR MINIMA

    International Nuclear Information System (INIS)

    Borovikov, Sergey N.; Pogorelov, Nikolai V.; Ebert, Robert W.

    2012-01-01

    The interaction between fast and slow solar wind (SW) due to the Sun's rotation creates corotating interaction regions (CIRs), which further interact with each other creating complex plasma structures at large heliospheric distances. We investigate the global influence of CIRs on the SW flow in the inner heliosheath between the heliospheric termination shock (TS) and the heliopause. The stream interaction model takes into account the major global effects due to slow-fast stream interaction near solar minima. The fast and slow wind parameters are derived from the Ulysses observations. We investigate the penetration of corotating structures through the TS and their further propagation through the heliosheath. It is shown that the heliosheath flow structure may experience substantial modifications, including local decreases in the radial velocity component observed by Voyager 1.

  13. A novel design for a cheap high temperature solar collector: The rotating solar boiler

    NARCIS (Netherlands)

    Luijtelaer, van J.P.H.; Kroon, M.C.

    2009-01-01

    In this work a novel type of high temperature solar collector is designed: the rotating solar boiler. This rotating solar boiler consists of two concentric tubes. The inner tube, called absorber, absorbs sunlight and boils water. The outer transparent tube, called cover, is filled with air. The

  14. 22 Year Periodicity in the Solar Differential Rotation

    Indian Academy of Sciences (India)

    tribpo

    1995). Recently, we determined periodicities in the solar differential rotation through the power spectrum analysis of the differential rotation parameters derived from the data on sunspot groups compiled from Greenwich Photoheliographic Results (GPR) during 1879 1976 and from Mt. Wilson velocity data during 1969 1994 ...

  15. Solar Internal Rotation and Dynamo Waves: A Two Dimensional ...

    Indian Academy of Sciences (India)

    tribpo

    Solar Internal Rotation and Dynamo Waves: A Two Dimensional. Asymptotic Solution in the Convection Zone ... We calculate here a spatial 2 D structure of the mean magnetic field, adopting real profiles of the solar internal ... of the asymptotic solution in low (middle) and high (right panel) latitudes. field is shifted towards the ...

  16. Solar rotation measurements at Mount Wilson. Pt. 2

    International Nuclear Information System (INIS)

    Labonte, B.J.; Howard, R.; Carnegie Institution of Washington, Pasadena

    1981-01-01

    Possible sources of systematic error in solar Doppler rotational velocities are examined. Scattered light is shown to affect the Mount Wilson solar rotation results, but this effect is not enough to bring the spectroscopic results in coincidence with the sunspot rotation. Interference fringes at the spectrograph focus at Mount Wilson have in two intervals affected the rotation results. It has been possible to correlate this error with temperature and thus correct for it. A misalignment between the entrance and exit slits is a possible source of error, but for the Mount Wilson slit configuration the amplitude of this effect is negligibly small. Rapid scanning of the solar image also produces no measurable effect. (orig.)

  17. Periodicities common to the solar atmosphere rotation and the functioning of human organism

    International Nuclear Information System (INIS)

    Tyagun, N.F.

    1995-01-01

    The study is made of the occurrence rates of menstrual cycle periods for ∼ 2000 women. Peaks on the distribution histogram, corresponding to 21, 25, 28 and 30 days, coincide with a set of axial rotation periods of the solar atmosphere. It is proposed that the functioning of human organism is determined not only by the Moon bu by the rithmics of solar system. 10 refs., 1 fig

  18. Differential rotation and the solar dynamo

    International Nuclear Information System (INIS)

    Stix, M.

    1976-01-01

    A number of numerical models for the generation of mean magnetic fields is examined and the fields are compared with the mean field of the Sun. In particular, αω-dynamos, which are based on differential rotation and cyclonic turbulence, are studied in the case of cylindrical surfaces of isorotation. Such dynamos have an oscillatory antisymmetric field as the most easily excited mode. Only models with an angular velocity which increases with increasing depth appear to be compatible with observations. A search for oscillatory ω x j-dynamos, where the α-effect is replaced by a different mean electric field perpendicular to the rotation vector ω and the mean current density j is also made. Oscillatory modes do exist for models with radial shear. Their migration is equatorwards for inwards increasing angular velocity. (orig./BJ) [de

  19. Innovative Solar Tracking Concept by Rotating Prism Array

    Directory of Open Access Journals (Sweden)

    Héctor García

    2014-01-01

    Full Text Available Solar energy has become one of the most promising renewable energies and is the most widely used nowadays. In order to achieve an optimum performance, both photovoltaic and solar thermal applications are required to track the position of the sun throughout the day and year in the most effective way possible to avoid a high negative impact on the system efficiency. The present paper attempts to describe a novel semipassive solar tracking concentrator (SPSTC in which, in order to track the sun, two independent arrays of polymethyl methacrylate (PMMA prisms are implemented to refract sunlight by rotating said prisms, thus being able to redirect solar radiation as desired. The first set is responsible for eliminating one of the directional components of the solar radiation; the task is achieved by rotating the prisms within the array at a specific angle. The second set deals with another of the sunlight’s directional components, transforming its direction into a completely perpendicular pattern to the array. Having downward vertical radiation makes it possible to implement a stationary Fresnel lens to concentrate the solar radiation for any application desired. The system is designed and validated using simulation software to prove the feasibility of the concept.

  20. 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

  1. Linear astrophysical dynamos in rotating spheres: Differential rotation, anisotropic turbulent magnetic diffusivity, and solar-stellar cycle magnetic parity

    International Nuclear Information System (INIS)

    Yoshimura, H.; Wang, Z.; Wu, F.

    1984-01-01

    Differential rotation dependence of the selection mechanism for magnetic parity of solar and stellar cycles is studied by assuming various differential rotation profiles inn the dynamo equation. The parity selection depends on propagation direction of oscillating magnetic fields in the form of dynamo waves which propagate along isorotation surfaces. When there is any radial gradient in the differential rotation, dynamo waves propagate either equatorward or poleward. In the former case, field systems of the two hemispheres approach each other and collide at the equator. Then, odd parity is selected. In the latter case, field systems of the two hemispheres recede from each other and do not collide at the equator, an even parity is selected. Thus the equatorial migration of wings of the butterfly iagram of the solar cycle and its odd parity are intrinsically related. In the case of purely latitudibnal differential rotation, dynamo waves propagate purely radially and growth rates of odd and even modes are nearly the same even when dynamo strength is weak when the parity selection mechanism should work most efficiently. In this case, anisotropy of turbulent diffusivity is a decisive factor to separate odd and even modes. Unlike in the case of radial-gradient-dominated differential rotation in which any difference between diffusivities for poloidal and toroidal fields enhancess the parity selection without changing the parity, the parity selection in the case of latitudinal-gradient-dominated differential rotation depends on the difference of diffusivities for poloidal and toroidal fields. When diffusivity for poloidal fields iss larger than that for toroidal fields, odd parity is selected; and when diffusivity for toroidal fields is larger, even parity is selected

  2. Optimum solar collector fluid flow rates

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    1996-01-01

    Experiments showed that by means of a standard electronically controlled pump, type UPE 2000 from Grundfos it is possible to control the flow rate in a solar collector loop in such a way that the flow rate is strongly influenced by the temperature of the solar collector fluid passing the pump....... The flow rate is increasing for increasing temperature.The flow rate at the high temperature level is typically 70 % greater than the flow rate at the low temperature level.Further, the energy consumption for the electronically controlled pump in a solar heating system will be somewhat smaller than...... the energy consumption of a normal ciculation pump in the solar heating system.Calculations showed that the highest thermal performances for small SDHW systems based on mantle tanks with constant volume flow rates in the solar collector loops are achieved if the flow rate is situated in the interval from 0...

  3. The structure of rotational discontinuities. [in solar wind

    Science.gov (United States)

    Neugebauer, M.

    1989-01-01

    This study examines the structures of a set of rotational discontinuities detected in the solar wind by the ISEE-3 spacecraft. It is found that the complexity of the structure increases as the angle theta between the propagation vector k and the magnetic field decreases. For rotational discontinuities that propagate at a large angle to the field with an ion (left-hand) sense of rotation, the magnetic hodograms tend to be flattened, in agreement with prior numerical simulations. When theta is large, angular 'overshoots' are often observed at one or both ends of the discontinuity. When the propagation is nearly parallel to the field (when theta is small), many different types of structure are seen, ranging from straight lines, to S-shaped curves, to complex, disorganized shapes.

  4. Stellar dynamism. Activity and rotation of solar stars observed from the Kepler satellite

    International Nuclear Information System (INIS)

    Ceillier, Tugdual

    2015-01-01

    This thesis concerns the study of seismic solar-like stars' rotation and magnetic activity. We use data from the Kepler satellite to study the rotational history of these stars throughout their evolution. This allows to have a more complete picture of stellar rotation and magnetism. In the first part, we present the context of this PhD: astro-seismology, the seismic study of stars. We continue by describing the tool we developed to measure surface rotation of stars using photometric data from Kepler. We compare it to other methodologies used by the community and show that its efficiency is very high. In the second part, we apply this tool to around 500 main-sequence and sub-giant solar-like stars. We measure surface rotation periods and activity levels for 300 of them. We show that the measured periods and the ages from astro-seismology do not agree well with the standard period-age relationships and propose to modify these relationships for stars older than the Sun. We also use the surface rotation as a constraint to estimate the internal rotation of a small number of seismic targets. We demonstrate that these stars have, like the Sun, a very low differential rotation ratio. In the third part, we apply our surface rotation-measuring tool to the most extensive sample of red giants observed by Kepler, comprising more than 17,000 stars. We identify more than 360 fast rotating red giants and compare our detection rates with the ones predicted by theory to better understand the reasons for this rapid rotation. We also use stellar modelling to reproduce the internal rotation profile of a particular red giant. This allows us to emphasize how important implementing new angular momentum transport mechanisms in stellar evolution codes is. This work offers new results that are useful to a very wide community of stellar physicists. It also puts strong constraints on the evolution of solar-like stars' rotation and magnetic activity. (author) [fr

  5. Rotational Laser Cooling of MgH+ Ions and Rotational Rate Measurements

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Staanum, Peter; Højbjerre, Klaus

    by varying a delay between two such pairs of firings and measuring the yield of the second pair obtain the refilling rates. These rotational transition rate measurements are not only of direct interest for us to understand our rotational state preparation schemes, but will be important input to quantum...

  6. Seismology of rapidly rotating and solar-like stars

    Science.gov (United States)

    Reese, Daniel Roy

    2018-05-01

    A great deal of progress has been made in stellar physics thanks to asteroseismology, the study of pulsating stars. Indeed, asteroseismology is currently the only way to probe the internal structure of stars. The work presented here focuses on some of the theoretical aspects of this domain and addresses two broad categories of stars, namely solar-like pulsators (including red giants), and rapidly rotating pulsating stars. The work on solar-like pulsators focuses on setting up methods for efficiently characterising a large number of stars, in preparation for space missions like TESS and PLATO 2.0. In particular, the AIMS code applies an MCMC algorithm to find stellar properties and a sample of stellar models which fit a set of seismic and classic observational constraints. In order to reduce computation time, this code interpolates within a precalculated grid of models, using a Delaunay tessellation which allows a greater flexibility on the construction of the grid. Using interpolated models based on the outputs from this code or models from other forward modelling codes, it is possible to obtain refined estimates of various stellar properties such as the mean density thanks to inversion methods put together by me and G. Buldgen, my former PhD student. Finally, I show how inversion-type methods can also be used to test more qualitative information such as whether a decreasing rotation profile is compatible with a set of observed rotational splittings and a given reference model. In contrast to solar-like pulsators, the pulsation modes of rapidly rotating stars remain much more difficult to interpret due to the complexity of the numerical calculations needed to calculate such modes, the lack of simple frequency patterns, and the fact that it is difficult to predict mode amplitudes. The work described here therefore focuses on addressing the above difficulties one at a time in the hopes that it will one day be possible to carry out detailed asteroseismology in these

  7. North–South Asymmetry of the Rotation of the Solar Magnetic Field

    Science.gov (United States)

    Xie, Jinglan; Shi, Xiangjun; Qu, Zhining

    2018-03-01

    Using the rotation rates of the solar magnetic field during solar cycles 21 to 23 obtained by Chu et al. by analyzing the synoptic magnetic maps produced by the NSO/Kitt Peak and SOHO/MDI during the years 1975 to 2008, the temporal variation of the equatorial rotation rate (A) and the latitude gradient of rotation (B) in the northern and southern hemispheres are studied separately. The results indicate that the rotation is more differential (about 4.3%) in the southern hemisphere in the considered time frame. It is found that the north–south asymmetry of A and the asymmetry of B show increasing trends in the considered time frame, while the north–south asymmetry of the solar activity shows a decreasing trend. There exists a significant negative correlation (at 95% confidence level) between the asymmetry of B and the asymmetry of the solar activity, and this may be due to stronger magnetic activity in a certain hemisphere that may suppress the differential rotation to some extent. The periodicities in the variation of A and B are also studied, and periods of about 5.0 and 10.5 yr (5.5 and 10.4 yr) can be found for the variation of the northern (southern) hemisphere B. Moreover, the north–south asymmetry of A and the asymmetry of B have similar periods of about 2.6–2.7 and 5.2–5.3 yr. Further, cross-correlation analysis indicates that there exists a phase difference (about eight months) between the northern and southern hemisphere B, and this means that the northern hemisphere B generally leads by about eight months.

  8. ROTATION PERIODS AND AGES OF SOLAR ANALOGS AND SOLAR TWINS REVEALED BY THE KEPLER MISSION

    International Nuclear Information System (INIS)

    Do Nascimento Jr, J.-D.; Meibom, S.; García, R. A.; Salabert, D.; Ceillier, T.; Mathur, S.; Anthony, F.; Da Costa, J. S.; Castro, M.; Barnes, S. A.

    2014-01-01

    A new sample of solar analogs and twin candidates has been constructed and studied, paying particular attention to their light curves from NASA's Kepler mission. This Letter aims to assess their evolutionary status, derive their rotation and ages, and identify those which are solar analogs or solar twin candidates. We separate out the subgiants that compose a large fraction of the asteroseismic sample, and which show an increase in the average rotation period as the stars ascend the subgiant branch. The rotation periods of the dwarfs, ranging from 6 to 30 days and averaging 19 days, allow us to assess their individual evolutionary states on the main sequence and to derive their ages using gyrochronology. These ages are found to be in agreement with a correlation coefficient of r = 0.79 with independent asteroseismic ages, where available. As a result of this investigation, we are able to identify 34 stars as solar analogs and 22 of them as solar twin candidates

  9. ROTATION PERIODS AND AGES OF SOLAR ANALOGS AND SOLAR TWINS REVEALED BY THE KEPLER MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Do Nascimento Jr, J.-D.; Meibom, S. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); García, R. A.; Salabert, D.; Ceillier, T. [Laboratoire AIM, CEA/DSM,CNRS, Univ. Paris Diderot-IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Mathur, S. [Space Science Institute, 4750 Walnut Street Suite 205, Boulder CO 80301 (United States); Anthony, F.; Da Costa, J. S.; Castro, M. [Universidade Federal do Rio Grande do Norte, UFRN, Dep. de Física Teórica e Experimental, DFTE, CP 1641, 59072-970 Natal, RN (Brazil); Barnes, S. A., E-mail: jdonascimento@cfa.harvard.edu [Leibniz-Institute for Astrophysics, Potsdam D-14467 (Germany)

    2014-08-01

    A new sample of solar analogs and twin candidates has been constructed and studied, paying particular attention to their light curves from NASA's Kepler mission. This Letter aims to assess their evolutionary status, derive their rotation and ages, and identify those which are solar analogs or solar twin candidates. We separate out the subgiants that compose a large fraction of the asteroseismic sample, and which show an increase in the average rotation period as the stars ascend the subgiant branch. The rotation periods of the dwarfs, ranging from 6 to 30 days and averaging 19 days, allow us to assess their individual evolutionary states on the main sequence and to derive their ages using gyrochronology. These ages are found to be in agreement with a correlation coefficient of r = 0.79 with independent asteroseismic ages, where available. As a result of this investigation, we are able to identify 34 stars as solar analogs and 22 of them as solar twin candidates.

  10. 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.

  11. Radar meteor rates and solar activity

    International Nuclear Information System (INIS)

    Prikryl, P.

    1983-01-01

    The short-term variation of diurnal radar meteor rates with solar activity represented by solar microwave flux Fsub(10.7), and sunspots relative number Rsub(z), is investigated. Applying the superposed-epoch analysis to the observational material of radar meteor rates from Christchurch (1960-61 and 1963-65), a decrease in the recorded radar rates is found during days of enhanced solar activity. No effect of geomagnetic activity similar to the one reported for the Swedish and Canadian radar meteor data was found by the author in the Christchurch data. A possible explanation of the absence of the geomagnetic effect on radar meteor rates from New Zealand due to a lower echo ceiling height of the Christchurch radar is suggested. The variation of the atmospheric parameters as a possible cause of the observed variation in radar meteor rates is also discussed. (author)

  12. The various contributions in Venus rotation rate and LOD

    Science.gov (United States)

    Cottereau, L.; Rambaux, N.; Lebonnois, S.; Souchay, J.

    2011-07-01

    Context. Thanks to the Venus Express Mission, new data on the properties of Venus could be obtained, in particular concerning its rotation. Aims: In view of these upcoming results, the purpose of this paper is to determine and compare the major physical processes influencing the rotation of Venus and, more particularly, the angular rotation rate. Methods: Applying models already used for Earth, the effect of the triaxiality of a rigid Venus on its period of rotation are computed. Then the variations of Venus rotation caused by the elasticity, the atmosphere, and the core of the planet are evaluated. Results: Although the largest irregularities in the rotation rate of the Earth on short time scales are caused by its atmosphere and elastic deformations, we show that the irregularities for Venus are dominated by the tidal torque exerted by the Sun on its solid body. Indeed, as Venus has a slow rotation, these effects have a large amplitude of two minutes of time (mn). These variations in the rotation rate are greater than the one induced by atmospheric wind variations that can reach 25-50 s of time (s), depending on the simulation used. The variations due to the core effects that vary with its size between 3 and 20 s are smaller. Compared to these effects, the influence of the elastic deformation caused by the zonal tidal potential is negligible. Conclusions: As the variations in the rotation of Venus reported here are close to 3 mn peak to peak, they should influence past, present, and future observations, thereby providing further constraints on the planet's internal structure and atmosphere.

  13. 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.

  14. Solar rotational cycle in lightning activity in Japan during the 18-19th centuries

    Science.gov (United States)

    Miyahara, Hiroko; Kataoka, Ryuho; Mikami, Takehiko; Zaiki, Masumi; Hirano, Junpei; Yoshimura, Minoru; Aono, Yasuyuki; Iwahashi, Kiyomi

    2018-04-01

    Thunderstorm and cloud activities sometimes show a 27-day period, and this has long been studied to uncover a possible important link to solar rotation. Because the 27-day variations in the solar forcing parameters such as solar ultraviolet and galactic cosmic rays become more prominent when the solar activity is high, it is expected that the signal of the 27-day period in meteorological phenomena may wax and wane according to the changes in the solar activity level. In this study, we examine in detail the intensity variations in the signal of the 27-day solar rotational period in thunder and lightning activity from the 18th to the 19th centuries based on 150-year-long records found in old diaries kept in Japan and discuss their relation with the solar activity levels. Such long records enable us to examine the signals of solar rotation at both high and low solar activity levels. We found that the signal of the solar rotational period in the thunder and lightning activity increases as the solar activity increases. In this study, we also discuss the possibility of the impact of the long-term climatological conditions on the signals of the 27-day period in thunder/lightning activities.

  15. Magnetism, planetary rotation and convection in the solar system

    CERN Document Server

    1985-01-01

    On the 6th, 7th' and 8th April 1983, a conference entitled "Magnetism, planetary rotation and convection in the Solar System" was held in the School of Physics at the University of Newcastle upon Tyne. The purpose of the meeting was to celebrate the 60th birthday of Prof. Stanley Keith Runcorn and his, and his students' and associates', several decades of scientific achievement. The social programme, which consisted of excursions in Northumberland and Durham with visits to ancient castles and churches, to Hexham Abbey and Durham Cathedral, and dinners in Newcastle and Durham, was greatly enjoyed by those attending the meeting and by their guests. The success ofthe scientific programme can be judged by this special edition of Geophysical Surveys which is derived mainly from the papers given at the meeting. The story starts in the late 1940s when the question of the origin of the magnetic field of the Earth and such other heavenly bodies as had at that time been discovered as having a magnetic field, was exerci...

  16. Temporal Variation of the Rotation of the Solar Mean Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J. L.; Shi, X. J.; Xu, J. C., E-mail: xiejinglan@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

    2017-04-01

    Based on continuous wavelet transformation analysis, the daily solar mean magnetic field (SMMF) from 1975 May 16 to 2014 July 31 is analyzed to reveal its rotational behavior. Both the recurrent plot in Bartels form and the continuous wavelet transformation analysis show the existence of rotational modulation in the variation of the daily SMMF. The dependence of the rotational cycle lengths on solar cycle phase is also studied, which indicates that the yearly mean rotational cycle lengths generally seem to be longer during the rising phase of solar cycles and shorter during the declining phase. The mean rotational cycle length for the rising phase of all of the solar cycles in the considered time is 28.28 ± 0.67 days, while for the declining phase it is 27.32 ± 0.64 days. The difference of the mean rotational cycle lengths between the rising phase and the declining phase is 0.96 days. The periodicity analysis, through the use of an auto-correlation function, indicates that the rotational cycle lengths have a significant period of about 10.1 years. Furthermore, the cross-correlation analysis indicates that there exists a phase difference between the rotational cycle lengths and solar activity.

  17. Diagnostics of the solar corona from comparison between Faraday rotation measurements and magnetohydrodynamic simulations

    International Nuclear Information System (INIS)

    Le Chat, G.; Cohen, O.; Kasper, J. C.; Spangler, S. R.

    2014-01-01

    Polarized natural radio sources passing behind the Sun experience Faraday rotation as a consequence of the electron density and magnetic field strength in coronal plasma. Since Faraday rotation is proportional to the product of the density and the component of the magnetic field along the line of sight of the observer, a model is required to interpret the observations and infer coronal structures. Faraday rotation observations have been compared with relatively ad hoc models of the corona. Here for the first time we compare these observations with magnetohydrodynamic (MHD) models of the solar corona driven by measurements of the photospheric magnetic field. We use observations made with the NRAO Very Large Array of 34 polarized radio sources occulted by the solar corona between 5 and 14 solar radii. The measurements were made during 1997 May, and 2005 March and April. We compare the observed Faraday rotation values with values extracted from MHD steady-state simulations of the solar corona. We find that (1) using a synoptic map of the solar magnetic field just one Carrington rotation off produces poorer agreements, meaning that the outer corona changes in the course of one month, even in solar minimum; (2) global MHD models of the solar corona driven by photospheric magnetic field measurements are generally able to reproduce Faraday rotation observations; and (3) some sources show significant disagreement between the model and the observations, which appears to be a function of the proximity of the line of sight to the large-scale heliospheric current sheet.

  18. An analysis of vibration-rotation lines of OH in the solar infrared spectrum

    NARCIS (Netherlands)

    Grevesse, N.; Sauval, A.J.; Dishoeck, van E.F.

    1984-01-01

    High resolution solar spectra have permitted the measurement with great accuracy of equivalent widths of vibration-rotation lines of OH in the X2Pi state near 3-micron wavelength. Using recent theoretical results for the transition probabilities, a solar oxygen abundance of (8.93 + or - 0.02) is

  19. Role of Interaction between Magnetic Rossby Waves and Tachocline Differential Rotation in Producing Solar Seasons

    Science.gov (United States)

    Dikpati, Mausumi; McIntosh, Scott W.; Bothun, Gregory; Cally, Paul S.; Ghosh, Siddhartha S.; Gilman, Peter A.; Umurhan, Orkan M.

    2018-02-01

    We present a nonlinear magnetohydrodynamic shallow-water model for the solar tachocline (MHD-SWT) that generates quasi-periodic tachocline nonlinear oscillations (TNOs) that can be identified with the recently discovered solar “seasons.” We discuss the properties of the hydrodynamic and magnetohydrodynamic Rossby waves that interact with the differential rotation and toroidal fields to sustain these oscillations, which occur due to back-and-forth energy exchanges among potential, kinetic, and magnetic energies. We perform model simulations for a few years, for selected example cases, in both hydrodynamic and magnetohydrodynamic regimes and show that the TNOs are robust features of the MHD-SWT model, occurring with periods of 2–20 months. We find that in certain cases multiple unstable shallow-water modes govern the dynamics, and TNO periods vary with time. In hydrodynamically governed TNOs, the energy exchange mechanism is simple, occurring between the Rossby waves and differential rotation. But in MHD cases, energy exchange becomes much more complex, involving energy flow among six energy reservoirs by means of eight different energy conversion processes. For toroidal magnetic bands of 5 and 35 kG peak amplitudes, both placed at 45° latitude and oppositely directed in north and south hemispheres, we show that the energy transfers responsible for TNO, as well as westward phase propagation, are evident in synoptic maps of the flow, magnetic field, and tachocline top-surface deformations. Nonlinear mode–mode interaction is particularly dramatic in the strong-field case. We also find that the TNO period increases with a decrease in rotation rate, implying that the younger Sun had more frequent seasons.

  20. A High Rated Solar Water Distillation Unit for Solar Homes

    Directory of Open Access Journals (Sweden)

    Abhishek Saxena

    2016-01-01

    Full Text Available India is presently focusing on complete utilization of solar energy and saving fossil fuels, which are limited. Various solar energy systems like solar cookers, solar water heaters, solar lanterns, solar PV lights, and solar lamps are continuously availing by the people of India at a low cost and on good subsidies. Apart from this, India is a solar energy promising country with a good number of solar homes (carrying solar energy systems in its various locations. The present paper focuses on a unique combination of solar dish cooker (SDC and solar water heater (SWH to produce distilled water with a high distillate and a high daily productivity. The procedure has been discussed on the basis of experimental testing to produce distilled water by combining an evacuated type SWH and a SDC. Experimentation has been carried out in MIT, Moradabad (longitude, 28.83°N, and latitude, 78.78°E by developing the same experimental setup on behalf of solar homes. The daily productivity of distilled water was found around 3.66 litres per day in full sunshine hours for an approximated pH value of 7.7 and a ppm value of 21. The payback period (PBP has been estimated around 1.16 years of the present system.

  1. Internal rotation of the Sun

    International Nuclear Information System (INIS)

    Duvall, T.L. Jr.; Goode, P.R.; Gouch, D.O.

    1984-01-01

    The frequency difference between prograde and retrograde sectoral solar oscillations is analysed to determine the rotation rate of the solar interior, assuming no latitudinal dependence. Much of the solar interior rotates slightly less rapidly than the surface, while the innermost part apparently rotates more rapidly. The resulting solar gravitational quadrupole moment is J 2 = (1.7 +- 0.4) x 10 -7 and provides a negligible contribution to current planetary tests of Einstein's theory of general relativity. (author)

  2. 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

  3. The impact of changing solar screen rotation angle and its opening aspect ratios on Daylight Availability in residential desert buildings

    KAUST Repository

    Sherif, Ahmed H.; Sabry, Hanan M.; Gadelhak, Mahmoud I.

    2012-01-01

    usually used to diffuse and prevent direct solar penetration into spaces. This paper investigates the impact of changing solar screen axial rotation angle and screen opening aspect ratio on daylighting performance in a typical residential living room space

  4. Enstrophy-based proper orthogonal decomposition of flow past rotating cylinder at super-critical rotating rate

    Science.gov (United States)

    Sengupta, Tapan K.; Gullapalli, Atchyut

    2016-11-01

    Spinning cylinder rotating about its axis experiences a transverse force/lift, an account of this basic aerodynamic phenomenon is known as the Robins-Magnus effect in text books. Prandtl studied this flow by an inviscid irrotational model and postulated an upper limit of the lift experienced by the cylinder for a critical rotation rate. This non-dimensional rate is the ratio of oncoming free stream speed and the surface speed due to rotation. Prandtl predicted a maximum lift coefficient as CLmax = 4π for the critical rotation rate of two. In recent times, evidences show the violation of this upper limit, as in the experiments of Tokumaru and Dimotakis ["The lift of a cylinder executing rotary motions in a uniform flow," J. Fluid Mech. 255, 1-10 (1993)] and in the computed solution in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)]. In the latter reference, this was explained as the temporal instability affecting the flow at higher Reynolds number and rotation rates (>2). Here, we analyze the flow past a rotating cylinder at a super-critical rotation rate (=2.5) by the enstrophy-based proper orthogonal decomposition (POD) of direct simulation results. POD identifies the most energetic modes and helps flow field reconstruction by reduced number of modes. One of the motivations for the present study is to explain the shedding of puffs of vortices at low Reynolds number (Re = 60), for the high rotation rate, due to an instability originating in the vicinity of the cylinder, using the computed Navier-Stokes equation (NSE) from t = 0 to t = 300 following an impulsive start. This instability is also explained through the disturbance mechanical energy equation, which has been established earlier in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)].

  5. Rotation of the Earth, solar activity and cosmic ray intensity

    Energy Technology Data Exchange (ETDEWEB)

    Barlyaeva, T.; Bard, E. [Aix-Marseille Univ., CNRS, IRD, Aix-en-Provence (France). CEREGE, College de France; Abarca-del-Rio, R. [Universidad de Concepcion (UDEC) (Chile). Dept. de Geofisica (DGEO)

    2014-10-01

    We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

  6. Rotation of the Earth, solar activity and cosmic ray intensity

    International Nuclear Information System (INIS)

    Barlyaeva, T.; Bard, E.

    2014-01-01

    We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

  7. Effects of solar radiation pressure torque on the rotational motion of an artificial satellite

    Science.gov (United States)

    Zanardi, Maria Cecilia F. P. S.; Vilhenademoraes, Rodolpho

    1992-01-01

    The motion of an artificial satellite about its center of mass is studied considering torques due to the gravity gradient and direct solar radiation pressure. A model for direct solar radiation torque is derived for a circular cylindrical satellite. An analytical solution is obtained by the method of variation of the parameters. This solution shows that the angular variables have secular variation but that the modulus of the rotational angular momentum, the projection of rotational angular momentum on the z axis of the moment of inertia and inertial axis z, suffer only periodic variations. Considering a hypothetical artificial satellite, a numerical application is demonstrated.

  8. 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

  9. A MODEL OF MAGNETIC BRAKING OF SOLAR ROTATION THAT SATISFIES OBSERVATIONAL CONSTRAINTS

    International Nuclear Information System (INIS)

    Denissenkov, Pavel A.

    2010-01-01

    The model of magnetic braking of solar rotation considered by Charbonneau and MacGregor has been modified so that it is able to reproduce for the first time the rotational evolution of both the fastest and slowest rotators among solar-type stars in open clusters of different ages, without coming into conflict with other observational constraints, such as the time evolution of the atmospheric Li abundance in solar twins and the thinness of the solar tachocline. This new model assumes that rotation-driven turbulent diffusion, which is thought to amplify the viscosity and magnetic diffusivity in stellar radiative zones, is strongly anisotropic with the horizontal components of the transport coefficients strongly dominating over those in the vertical direction. Also taken into account is the poloidal field decay that helps to confine the width of the tachocline at the solar age. The model's properties are investigated by numerically solving the azimuthal components of the coupled momentum and magnetic induction equations in two dimensions using a finite element method.

  10. WHAT SETS THE INITIAL ROTATION RATES OF MASSIVE STARS?

    International Nuclear Information System (INIS)

    Rosen, Anna L.; Krumholz, Mark R.; Ramirez-Ruiz, Enrico

    2012-01-01

    The physical mechanisms that set the initial rotation rates in massive stars are a crucial unknown in current star formation theory. Observations of young, massive stars provide evidence that they form in a similar fashion to their low-mass counterparts. The magnetic coupling between a star and its accretion disk may be sufficient to spin down low-mass pre-main-sequence (PMS) stars to well below breakup at the end stage of their formation when the accretion rate is low. However, we show that these magnetic torques are insufficient to spin down massive PMS stars due to their short formation times and high accretion rates. We develop a model for the angular momentum evolution of stars over a wide range in mass, considering both magnetic and gravitational torques. We find that magnetic torques are unable to spin down either low-mass or high-mass stars during the main accretion phase, and that massive stars cannot be spun down significantly by magnetic torques during the end stage of their formation either. Spin-down occurs only if massive stars' disk lifetimes are substantially longer or their magnetic fields are much stronger than current observations suggest.

  11. Fast Rotating solar-like stars using asteroseismic datasets

    DEFF Research Database (Denmark)

    A. García, R.; Ceillier, T.; Campante, T.

    2011-01-01

    The NASA Kepler mission is providing an unprecedented set of asteroseismic data. In particular, short-cadence lightcurves (~60s samplings), allow us to study solar-like stars covering a wide range of masses, spectral types and evolutionary stages. Oscillations have been observed in around 600 out...

  12. Solar rotation and activity in the past and their possible influence upon the evolution of life

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, E H

    1980-01-01

    Observations of enhanced spot active main sequence stars of solar type led to the formulation of the hypothesis which states that the rotational angular momentum, J/sub r/, of stars with spectral types later than F5 determines the intensity of their magnetic activity, bar A. Such very spot active stars are exclusively found as the components of fairly close binary stars, and show rotation periods smaller or more or less synchronous to the orbital period. Single stars of the lower main sequence are generally slow rotators, and do not show detectable activity in optical spectral regions, similar to the Sun if observed from stellar distances.

  13. 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

  14. The circulation pattern and day-night heat transport in the atmosphere of a synchronously rotating aquaplanet: Dependence on planetary rotation rate

    Science.gov (United States)

    Noda, S.; Ishiwatari, M.; Nakajima, K.; Takahashi, Y. O.; Takehiro, S.; Onishi, M.; Hashimoto, G. L.; Kuramoto, K.; Hayashi, Y.-Y.

    2017-01-01

    In order to investigate a possible variety of atmospheric states realized on a synchronously rotating aquaplanet, an experiment studying the impact of planetary rotation rate is performed using an atmospheric general circulation model (GCM) with simplified hydrological and radiative processes. The entire planetary surface is covered with a swamp ocean. The value of planetary rotation rate is varied from zero to the Earth's, while other parameters such as planetary radius, mean molecular weight and total mass of atmospheric dry components, and solar constant are set to the present Earth's values. The integration results show that the atmosphere reaches statistically equilibrium states for all runs; none of the calculated cases exemplifies the runaway greenhouse state. The circulation patterns obtained are classified into four types: Type-I characterized by the dominance of a day-night thermally direct circulation, Type-II characterized by a zonal wave number one resonant Rossby wave over a meridionally broad westerly jet on the equator, Type-III characterized by a long time scale north-south asymmetric variation, and Type-IV characterized by a pair of mid-latitude westerly jets. With the increase of planetary rotation rate, the circulation evolves from Type-I to Type-II and then to Type-III gradually and smoothly, whereas the change from Type-III to Type-IV is abrupt and discontinuous. Over a finite range of planetary rotation rate, both Types-III and -IV emerge as statistically steady states, constituting multiple equilibria. In spite of the substantial changes in circulation, the net energy transport from the day side to the night side remains almost insensitive to planetary rotation rate, although the partition into dry static energy and latent heat energy transports changes. The reason for this notable insensitivity is that the outgoing longwave radiation over the broad area of the day side is constrained by the radiation limit of a moist atmosphere, so that the

  15. 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

  16. Resonant amplification of neutrino spin rotation in matter and the solar-neutrino problem

    International Nuclear Information System (INIS)

    Akhmedov, E.Kh.

    1988-01-01

    It is shown that in the presence of matter there can occur resonant amplification of the flavor-changing neutrino spin rotation in transverse magnetic fields, which is roughly analogous to the Mikheyev-Smirnov-Wolfenstein effect in neutrino oscillations. Possible consequences for solar neutrinos are briefly discussed. (orig.)

  17. Differential rotation and giant cell circulation of the solar Ca+-network

    International Nuclear Information System (INIS)

    Schroeter, E.H.; Woehl, H.

    1976-01-01

    High precision computer controlled tracings of bright Ca + -mottles were performed during 1974 and 1975 at the Locarno Observatory of Gottingen to study solar differential rotation and to search for giant cell circulation pattern. The method consists of measuring the position of 5-15 bright Ca + - mottles with respect to the center of the solar disc every 10 to 15 min during 4h every day. From a linear least square fit of the observed positions the solar-latitude and longitude were computed for the beginning and the end of the daily 4h observation period. From this the components in latitude and longitude of the proper motions were derived which result from the differential rotation, possible giant cell circulation and the small scale random walk of these features. (Auth.)

  18. SUN-LIKE MAGNETIC CYCLES IN THE RAPIDLY ROTATING YOUNG SOLAR ANALOG HD 30495

    International Nuclear Information System (INIS)

    Egeland, Ricky; Metcalfe, Travis S.; Hall, Jeffrey C.; Henry, Gregory W.

    2015-01-01

    A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial (∼2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has an unusual evolutionary history. In this work, we present new and archival observations of dual magnetic cycles in the young solar analog HD 30495, a ∼1 Gyr old G1.5 V star with a rotation period near 11 days. This star falls squarely on the relationships established by the broader stellar sample, with short-period variations at ∼1.7 years and a long cycle of ∼12 years. We measure three individual long-period cycles and find durations ranging from 9.6 to 15.5 years. We find the short-term variability to be intermittent, but present throughout the majority of the time series, though its occurrence and amplitude are uncorrelated with the longer cycle. These essentially solar-like variations occur in a Sun-like star with more rapid rotation, though surface differential rotation measurements leave open the possibility of a solar equivalence

  19. The effects of mantle and anelasticity on nutations, earth tides, and tidal variations in rotation rate

    Science.gov (United States)

    Wahr, John; Bergen, Zachary

    1986-01-01

    The paper models the effects of mantle anelasticity on luni-solar nutations, on tidal deformation, on tidal variations in rotation rate, and on the eigenfrequency of the free core nutation. The results can be used to invert observations to solve for the anelastic contributions to the shear and bulk moduli of the upper and lower mantle. Specific anelastic models are used to numerically estimate the effects of anelasticity on these geodetic observables. The nutation estimates are compared with observational results. Among the conclusions: (1) mantle anelasticity is likely to be the most important source of damping for the free core nutation; (2) present VLBI nutation results are, in principle, accurate enough to usefully bound anelasticity at diurnal periods. But the discrepancy between the VLBI observed nutations and the 1984 IAU nutation model cannot be explained by anelasticity and is not yet well enough understood to allow anelasticity to be determined from the data.

  20. Rotation Rate of Saturn's Magnetosphere using CAPS Plasma Measurements

    Science.gov (United States)

    Sittler, E.; Cooper, J.; Simpson, D.; Paterson, W.

    2012-01-01

    We present the present status of an investigation of the rotation rate of Saturn 's magnetosphere using a 3D velocity moment technique being developed at Goddard which is similar to the 2D version used by Sittler et al. (2005) [1] for SOI and similar to that used by Thomsen et al. (2010). This technique allows one to nearly cover the full energy range of the CAPS IMS from 1 V less than or equal to E/Q less than 50 kV. Since our technique maps the observations into a local inertial frame, it does work during roll manoeuvres. We have made comparisons with Wilson et al. (2008) [2] (2005-358 and 2005-284) who performs a bi-Maxwellian fit to the ion singles data and our results are nearly identical. We will also make comparisons with results by Thomsen et al. (2010) [3]. Our analysis uses ion composition data to weight the non-compositional data, referred to as singles data, to separate H+, H2+ and water group ions (W+) from each other. The ion data set is especially valuable for measuring flow velocities for protons, which are more difficult to derive using singles data within the inner magnetosphere, where the signal is dominated by heavy ions (i.e., proton peak merges with W+ peak as low energy shoulder). Our technique uses a flux function, which is zero in the proper plasma flow frame, to estimate fluid parameter uncertainties. The comparisons investigate the experimental errors and potential for systematic errors in the analyses, including ours. The rolls provide the best data set when it comes to getting 4PI coverage of the plasma but are more susceptible to time aliasing effects. Since our analysis is a velocity moments technique it will work within the inner magnetosphere where pickup ions are important and velocity distributions are non-Maxwellian. So, we will present results inside Enceladus' L shell and determine if mass loading is important. In the future we plan to make comparisons with magnetic field observations, use Saturn ionosphere conductivities as

  1. TIME-DEPENDENT NONEXTENSIVITY ARISING FROM THE ROTATIONAL EVOLUTION OF SOLAR-TYPE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Silva, J. R. P.; Nepomuceno, M. M. F.; Soares, B. B.; De Freitas, D. B., E-mail: joseronaldo@uern.br [Departamento de Física, Universidade do Estado do Rio Grande do Norte, Mossoró-RN (Brazil)

    2013-11-01

    Nonextensive formalism is a generalization of the Boltzmann-Gibbs statistics. In this formalism, the entropic index q is a quantity characterizing the degree of nonextensivity and is interpreted as a parameter of long-memory or long-range interactions between the components of the system. Since its proposition in 1988, this formalism has been applied to investigate a wide variety of natural phenomena. In stellar astrophysics, a theoretical distribution function based on nonextensive formalism (q distributions) has been successfully applied to reproduce the distribution of stellar radial and rotational velocity data. In this paper, we investigate the time variation of the entropic index q obtained from the distribution of rotation, Vsin i, for a sample of 254 rotational data for solar-type stars from 11 open clusters aged between 35.5 Myr and 2.6 Gyr. As a result, we have found an anti-correlation between the entropic index q and the age of clusters, and that the distribution of rotation Vsin i for these stars becomes extensive for an age greater than about 170 Myr. Assuming that the parameter q is associated with long-memory effects, we suggest that the memory of the initial angular momentum of solar-type stars can be scaled by the entropic index q. We also propose a physical link between the parameter q and the magnetic braking of stellar rotation.

  2. EVIDENCE FOR ROTATIONAL MOTIONS IN THE FEET OF A QUIESCENT SOLAR PROMINENCE

    International Nuclear Information System (INIS)

    Orozco Suárez, D.; Asensio Ramos, A.; Trujillo Bueno, J.

    2012-01-01

    We present observational evidence of apparent plasma rotational motions in the feet of a solar prominence. Our study is based on spectroscopic observations taken in the He I 1083.0 nm multiplet with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope. We recorded a time sequence of spectra with 34 s cadence placing the slit of the spectrograph almost parallel to the solar limb and crossing two feet of an intermediate size, quiescent hedgerow prominence. The data show opposite Doppler shifts, ±6 km s –1 , at the edges of the prominence feet. We argue that these shifts may be interpreted as prominence plasma rotating counterclockwise around the vertical axis to the solar surface as viewed from above. The evolution of the prominence seen in EUV images taken with the Solar Dynamics Observatory provided us with clues to interpret the results as swirling motions. Moreover, time-distance images taken far from the central wavelength show plasma structures moving parallel to the solar limb with velocities of about 10-15 km s –1 . Finally, the shapes of the observed intensity profiles suggest the presence of, at least, two components at some locations at the edges of the prominence feet. One of them is typically Doppler shifted (up to ∼20 km s –1 ) with respect to the other, thus suggesting the existence of supersonic counter-streaming flows along the line of sight.

  3. Photocatalytic degradation of aniline using an autonomous rotating drum reactor with both solar and UV-C artificial radiation.

    Science.gov (United States)

    Durán, A; Monteagudo, J M; San Martín, I; Merino, S

    2018-03-15

    The aim of this work was to evaluate the performance of a novel self-autonomous reactor technology (capable of working with solar irradiation and artificial UV light) for water treatment using aniline as model compound. This new reactor design overcomes the problems of the external mass transfer effect and the accessibility to photons occurring in traditional reaction systems. The UV-light source is located inside the rotating quartz drums (where TiO 2 is immobilized), allowing light to easily reach the water and the TiO 2 surface. Several processes (UV, H 2 O 2 , Solar, TiO 2 , Solar/TiO 2 , Solar/TiO 2 /H 2 O 2 and UV/Solar/H 2 O 2 /TiO 2 ) were tested. The synergy between Solar/H 2 O 2 and Solar/TiO 2 processes was quantified to be 40.3% using the pseudo-first-order degradation rate. The apparent photonic efficiency, ζ, was also determined for evaluating light utilization. For the Solar/TiO 2 /H 2 O 2 process, the efficiency was found to be practically constant (0.638-0.681%) when the film thickness is in the range of 1.67-3.87 μm. However, the efficiency increases up to 2.67% when artificial UV light was used in combination, confirming the efficient design of this installation. Thus, if needed, lamps can be switched on during cloudy days to improve the degradation rate of aniline and its mineralization. Under the optimal conditions selected for the Solar/TiO 2 /H 2 O 2 process ([H 2 O 2 ] = 250 mg/L; pH = 4, [TiO 2 ] = 0.65-1.25 mg/cm 2 ), 89.6% of aniline is degraded in 120 min. If the lamps are switched on, aniline is completely degraded in 10 min, reaching 85% of mineralization in 120 min. TiO 2 was re-used during 5 reaction cycles without apparent loss in activity (Solar/TiO 2 /H 2 O 2 process was found to have lower operation costs than other systems described in literature (0.67 €/m 3 ). Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. 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.

  5. System and Method for Determining Rate of Rotation Using Brushless DC Motor

    Science.gov (United States)

    Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is squared. The squared outputs associated with each winding are combined, with the square root being taken of such combination, to produce a DC output proportional only to the rate of rotation of the motor's shaft.

  6. Rate of rotation measurement using back-EMFS associated with windings of a brushless DC motor

    Science.gov (United States)

    Howard, David E. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is integrated and multiplied by the back-emf associated with an adjacent winding. The multiplied outputs associated with each winding are combined to produce a directionally sensitive DC output proportional only to the rate of rotation of the motor's shaft.

  7. Rotating solid foam reactors : mass transfer and reaction rate

    NARCIS (Netherlands)

    Tschentscher, R.

    2012-01-01

    In this thesis the performance and applicability of rotating solid foam stirrers is investigated. The stirrer consists, thereby of a solid, highly porous structure, which is used as stirrer and catalyst support simultaneously. The solid foam block occupies a large part of the reactor volume.

  8. Consequences of high effective Prandtl number on solar differential rotation and convective velocity

    Science.gov (United States)

    Karak, Bidya Binay; Miesch, Mark; Bekki, Yuto

    2018-04-01

    Observations suggest that the large-scale convective velocities obtained by solar convection simulations might be over-estimated (convective conundrum). One plausible solution to this could be the small-scale dynamo which cannot be fully resolved by global simulations. The small-scale Lorentz force suppresses the convective motions and also the turbulent mixing of entropy between upflows and downflows, leading to a large effective Prandtl number (Pr). We explore this idea in three-dimensional global rotating convection simulations at different thermal conductivity (κ), i.e., at different Pr. In agreement with previous non-rotating simulations, the convective velocity is reduced with the increase of Pr as long as the thermal conductive flux is negligible. A subadiabatic layer is formed near the base of the convection zone due to continuous deposition of low entropy plumes in low-κ simulations. The most interesting result of our low-κ simulations is that the convective motions are accompanied by a change in the convection structure that is increasingly influenced by small-scale plumes. These plumes tend to transport angular momentum radially inward and thus establish an anti-solar differential rotation, in striking contrast to the solar rotation profile. If such low diffusive plumes, driven by the radiative-surface cooling, are present in the Sun, then our results cast doubt on the idea that a high effective Pr may be a viable solution to the solar convective conundrum. Our study also emphasizes that any resolution of the conundrum that relies on the downward plumes must take into account the angular momentum transport and heat transport.

  9. SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA

    Energy Technology Data Exchange (ETDEWEB)

    Scargle, Jeffrey D.; Worden, Simon P. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Keil, Stephen L. [National Solar Observatory, P.O. Box 57, Sunspot, NM 88349 (United States)

    2013-07-01

    Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

  10. On a relation of geomagnetic activity, solar wind velocity and irregularity of daily rotation of the Earth

    International Nuclear Information System (INIS)

    Kalinin, Yu.D.; Kiselev, V.M.

    1980-01-01

    A possibility of the presence of statistic relation between the changes of the Earth rotation regime and the mean velocity of solar wind is discussed. The ratio between the solar wind velocity observed and planetary index of geomagnetic activity am is used to determine the annual average values of solar wind velocity beyond the twentieth cycle of solar activity. The restored changes of solar wind velocity are compared with solar conditioned variations of the Earth day duration and it is shown that the correspondence takes place only at frequencies lower the frequency of 11-year cycle [ru

  11. M-number dependence of rotation period of the solar magnetic field and its effect on coronal hole and solar flare

    International Nuclear Information System (INIS)

    Saito, Takao; Oki, Tosio

    1989-01-01

    The photospheric magnetic field is revealed to rotate with different solar rotation periods depending on its m-number, or its longitudinal range. The m-dependent rotation reveals the unexplained solar cycle variation of the 28-day period of the IMF 2-sector structure in inclining/minimum years and of the 27-day period in the declining/minimum years. The m-dependent rotation reveals also the unexplained 155-day periodicity in the occurrence of solar flare clusters, suggesting a motion of the sunspot field relative to the large-scale field. The IMF sector structure is closely related to recurrent geomagnetic storms, while the flare occurrence is related to sporadic SC storms. Hence, the m-dependent rotation is quite important in the study of the STE forecast. (author)

  12. Large scale circulation in the convection zone and solar differential rotation

    Energy Technology Data Exchange (ETDEWEB)

    Belvedere, G [Instituto di Astronomia dell' Universita di Catania, 95125 Italy; Paterno, L [Osservatorio Astrofisico di Catania, 95125 Italy

    1976-04-01

    In this paper the dependence on depth and latitude of the solar angular velocity produced by a meridian circulation in the convection zone is studied assuming that the main mechanism responsible for setting up and driving the circulation is the interaction of rotation with convection. The first order equations (perturbation of the spherically symmetric state are solved in the Boussinesq approximation and in the steady state for the axissymmetric case. The interaction of convection with rotation is modelled by a convective transport coefficient. The model is consistent with the fact that the interaction of convection with rotation sets up a circulation (driven by the temperature gradient) which carries angular momentum toward the equator against the viscous friction. Unfortunately also a large flux variation at the surface is obtained. Nevertheless it seems that the model has the basic requisites for correct dynamo action.

  13. Solar rotation and activity in the past and their possible influence upon the evolution of life

    International Nuclear Information System (INIS)

    Geyer, E.H.

    1981-01-01

    It is proposed that the rotational angular momentum of the lower Main Sequence stars determines the intensity of their magnetic spot activity. As a consequence of this feedback coupling, the stellar rotation and the activity decay exponentially by magnetic braking of the induced stellar flare- and wind-activity. Therefore, the Sun should have rotated much faster and must have shown a very enhanced activity in its early history. This strong solar activity in the past could have influenced the evolution of terrestrial life, and may explain the stagnation of maritime life for about 2 x 10 9 yr, the diversification of species during the Cambrian formation, and the land conquest by life in the upper Silurian system. (Auth.)

  14. Solar rotation and activity in the past and their possible influence upon the evolution of life

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, E H [Bonn Univ. (Germany, F.R.). Sternwarte

    1981-06-01

    It is proposed that the rotational angular momentum of the lower Main Sequence stars determines the intensity of their magnetic spot activity. As a consequence of this feedback coupling, the stellar rotation and the activity decay exponentially by magnetic braking of the induced stellar flare- and wind-activity. Therefore, the Sun should have rotated much faster and must have shown a very enhanced activity in its early history. This strong solar activity in the past could have influenced the evolution of terrestrial life, and may explain the stagnation of maritime life for about 2 x 10/sup 9/ yr, the diversification of species during the Cambrian formation, and the land conquest by life in the upper Silurian system.

  15. Faraday rotation fluctutation spectra observed during solar occultation of the Helios spacecraft

    Science.gov (United States)

    Andreev, V.; Efimov, A. I.; Samoznaev, L.; Bird, M. K.

    1995-01-01

    Faraday rotation (FR) measurements using linearly polarized radio signals from the two Helios spacecraft were carried out during the period from 1975 to 1984. This paper presents the results of a spectral analysis of the Helios S-band FR fluctuations observed at heliocentric distances from 2.6 to 15 solar radii during the superior conjunctions 1975-1983. The mean intensity of the FR fluctuations does not exceed the noise level for solar offsets greater than ca. 15 solar radii. The rms FR fluctuation amplitude increases rapidly as the radio ray path approaches the Sun, varying according to a power law (exponent: 2.85 +/- 0.15) at solar distances 4-12 solar radii. At distances inside 4 solar radii the increase is even steeper (exponent: 5.6 +/- 0.2). The equivalent two-dimensional FR fluctuation spectrum is well modeled by a single power-law over the frequency range from 5 to 50 mHz. For heliocentric distances larger than 4 solar radii the spectral index varies between 1.1 and 1.6 with a mean value of 1.4 +/- 0.2, corresponding to a 3-D spectral index p = 2.4. FR fluctuations thus display a somwhat lower spectral index compared with phase and amplitude fluctuations. Surprisingly high values of the spectral index were found for measurements inside 4 solar radii (p = 2.9 +/- 0.2). This may arise from the increasingly dominant effect of the magnetic field on radio wave propagation at small solar offsets. Finally, a quasiperiodic component, believed to be associated with Alfven waves, was discovered in some (but not all!) fluctuation spectra observed simultaneously at two ground stations. Characteristic periods and bulk velocities of this component were 240 +/- 30 sec and 300 +/- 60 km/s, respectively.

  16. Efficiencies of flat plate solar collectors at different flow rates

    DEFF Research Database (Denmark)

    Chen, Ziqian; Furbo, Simon; Perers, Bengt

    2012-01-01

    Two flat plate solar collectors for solar heating plants from Arcon Solvarme A/S are tested in a laboratory test facility for solar collectors at Technical University of Denmark (DTU). The collectors are designed in the same way. However, one collector is equipped with an ETFE foil between...... the absorber and the cover glass and the other is without ETFE foil. The efficiencies for the collectors are tested at different flow rates. On the basis of the measured efficiencies, the efficiencies for the collectors as functions of flow rate are obtained. The calculated efficiencies are in good agreement...

  17. Thermal bifurcation in the upper solar photosphere inferred from heterodyne spectroscopy of OH rotational lines

    Science.gov (United States)

    Deming, D.; Hillman, J. J.; Kostiuk, T.; Mumma, M. J.; Zipoy, D. M.

    1984-01-01

    Low noise high spectral resolution observations of two pure rotation transitions of OH from the solar photosphere were obtained. The observations were obtained using the technique of optically null-balanced infrared heterodyne spectroscopy, and consist of center-to-limb line profiles of a v=1 and a v=0 transition near 12 microns. These lines should be formed in local thermodynamic equilibrium (LTE), and are diagnostics of the thermal structure of the upper photosphere. The v=0 R22 (24.5)e line strengthens at the solar limb, in contradiction to the predictions of current one dimensional photospheric models. Data for this line support a two dimensional model in which horizontal thermal fluctuations of order + or - 800K occur in the region Tau (sub 5000) approximately .001 to .01. This thermal bifurcation may be maintained by the presence of magnetic flux tubes, and may be related to the solar limb extensions observed in the 30 to 200 micron region.

  18. Helios-1 Faraday rotation experiment - Results and interpretations of the solar occultations in 1975

    Science.gov (United States)

    Volland, H.; Bird, M. K.; Levy, G. S.; Stelzried, C. T.; Seidel, B. L.

    1977-01-01

    The first of two solar occultations of the satellite Helios-1 in 1975 occurred in April when the satellite's ray path approached the west limb of the sun to a minimum distance of 1.63 solar radii. The second occultation took place in late August/early September when Helios-1 was totally eclipsed by the photosphere. Measurements of the polarization angle of the linearly polarized telemetry signal were performed with automatic tracking polarimeters at the 64 m Goldstone Tracking Station in California and also at the 100 m radio telescope in Effelsberg, West Germany. The coronal Faraday rotation as a function of the solar offset for both occultations is shown in graphs. The theoretical significance of the observations is investigated.

  19. On the Terminal Rotation Rates of Giant Planets

    Science.gov (United States)

    Batygin, Konstantin

    2018-04-01

    Within the general framework of the core-nucleated accretion theory of giant planet formation, the conglomeration of massive gaseous envelopes is facilitated by a transient period of rapid accumulation of nebular material. While the concurrent build-up of angular momentum is expected to leave newly formed planets spinning at near-breakup velocities, Jupiter and Saturn, as well as super-Jovian long-period extrasolar planets, are observed to rotate well below criticality. In this work, we demonstrate that the large luminosity of a young giant planet simultaneously leads to the generation of a strong planetary magnetic field, as well as thermal ionization of the circumplanetary disk. The ensuing magnetic coupling between the planetary interior and the quasi-Keplerian motion of the disk results in efficient braking of planetary rotation, with hydrodynamic circulation of gas within the Hill sphere playing the key role of expelling spin angular momentum to the circumstellar nebula. Our results place early-stage giant planet and stellar rotation within the same evolutionary framework, and motivate further exploration of magnetohydrodynamic phenomena in the context of the final stages of giant planet formation.

  20. Faraday rotation fluctuations of MESSENGER radio signals through the equatorial lower corona near solar minimum

    Science.gov (United States)

    Wexler, D. B.; Jensen, E. A.; Hollweg, J. V.; Heiles, C.; Efimov, A. I.; Vierinen, J.; Coster, A. J.

    2017-02-01

    Faraday rotation (FR) of transcoronal radio transmissions from spacecraft near superior conjunction enables study of the temporal variations in coronal plasma density, velocity, and magnetic field. The MESSENGER spacecraft 8.4 GHz radio, transmitting through the corona with closest line-of-sight approach 1.63-1.89 solar radii and near-equatorial heliolatitudes, was recorded soon after the deep solar minimum of solar cycle 23. During egress from superior conjunction, FR gradually decreased, and an overlay of wave-like FR fluctuations (FRFs) with periods of hundreds to thousands of seconds was found. The FRF power spectrum was characterized by a power law relation, with the baseline spectral index being -2.64. A transient power increase showed relative flattening of the spectrum and bands of enhanced spectral power at 3.3 mHz and 6.1 mHz. Our results confirm the presence of coronal FRF similar to those described previously at greater solar offset. Interpreted as Alfvén waves crossing the line of sight radially near the proximate point, low-frequency FRF convey an energy flux density higher than that of the background solar wind kinetic energy, but only a fraction of that required to accelerate the solar wind. Even so, this fraction is quite variable and potentially escalates to energetically significant values with relatively modest changes in estimated magnetic field strength and electron concentration. Given the uncertainties in these key parameters, as well as in solar wind properties close to the Sun at low heliolatitudes, we cannot yet confidently assign the quantitative role for Alfvén wave energy from this region in driving the slow solar wind.

  1. Advancements in solar stills for enhanced flow rate

    Science.gov (United States)

    Mishra, Sourav; Dubey, Maneesh; Raghuwanshi, Jitendra; Sharma, Vipin

    2018-05-01

    All over the world there is a scarcity of water and it is difficult to access potable water. Due to this most of the people are affected by diseases that are caused due to drinking of polluted water. There are technologies through which we can purify polluted water but the only problem is these technologies uses electrical energy. Since solar energy is abundant in nature therefore we can use solar as an energy source in solar stills for water distillation. Solar stills can be used in village areas where there is no electricity. It is simple and also economic in construction. This article addresses advancement in solar distillation and usage of nanofluids for enhancement in flow rate.

  2. Early postoperative fluoroquinolone use is associated with an increased revision rate after arthroscopic rotator cuff repair.

    Science.gov (United States)

    Cancienne, Jourdan M; Brockmeier, Stephen F; Rodeo, Scott A; Young, Chris; Werner, Brian C

    2017-07-01

    To evaluate the association of postoperative fluoroquinolone use following arthroscopic primary rotator cuff repair with failure requiring revision rotator cuff repair. An insurance database was queried for patients undergoing rotator cuff repair from 2007 to 2015. These patients were divided into three groups: (1) patients prescribed fluoroquinolones within 6 months postoperatively (divided into 0-2, 2-4, and 4-6 months), (2) a matched negative control cohort of patients not prescribed fluoroquinolones, and (3) a matched positive control cohort of patients prescribed fluoroquinolones between 6 and 18 months following rotator cuff repair. Rates of failure requiring revision rotator cuff repair were compared within 2 years. A total of 1292 patients were prescribed fluoroquinolones within 6 months after rotator cuff repair, including 442 within 2 months, 433 within 2 to 4 months, and 417 within 4 to 6 months, and were compared to 5225 matched negative controls and 1597 matched positive controls. The rate of revision rotator cuff repair was significantly higher in patients prescribed fluoroquinolones within 2 months (6.1 %) compared to matched negative (2.2 %, P = 0.0009) and positive controls (2.4 %, P = 0.0026). There were no significant differences in the rate of revision rotator cuff repair when fluoroquinolones were prescribed >2 months after rotator cuff repair. Early use of fluoroquinolones following rotator cuff repair was independently associated with significantly increased rates of failure requiring revision rotator cuff repair. This is the first clinical study examining the association of postoperative fluoroquinolone use with failure following arthroscopic rotator cuff repair. III.

  3. Exciting a rotating mass on a spring without change to its rotation rate

    International Nuclear Information System (INIS)

    Kenyon, Kern E.

    2001-01-01

    An exact mathematical solution, in terms of elementary functions, is presented for the two-dimensional problem of a mass rotating on a linear spring. The two governing equations in polar coordinates are nonlinear, coupled ordinary differential equations, but they can be solved analytically in sequence. In general, the orbit of the mass is an ellipse with the fixed end of the spring located at the centre of the ellipse. The orbital frequency is identical to the natural frequency of the spring and it is independent of the amplitude of the motion (independent of the major and minor axes of the ellipse). Based on the solution the following claim is made. No matter how the mass is perturbed, within its plane of motion, the orbital frequency will remain constant. The disturbance can be infinitesimal or finite and it can cause either the total energy or the angular momentum of the system or both to increase or decrease but the orbital period will not change. It follows from the fixed end of the spring being at the ellipse's centre that the radial vibration of the mass has twice the natural frequency of the spring; i.e. two maxima and minima in one orbital period, which is not possible unless there is rotation. (author)

  4. Errors of car wheels rotation rate measurement using roller follower on test benches

    Science.gov (United States)

    Potapov, A. S.; Svirbutovich, O. A.; Krivtsov, S. N.

    2018-03-01

    The article deals with rotation rate measurement errors, which depend on the motor vehicle rate, on the roller, test benches. Monitoring of the vehicle performance under operating conditions is performed on roller test benches. Roller test benches are not flawless. They have some drawbacks affecting the accuracy of vehicle performance monitoring. Increase in basic velocity of the vehicle requires increase in accuracy of wheel rotation rate monitoring. It determines the degree of accuracy of mode identification for a wheel of the tested vehicle. To ensure measurement accuracy for rotation velocity of rollers is not an issue. The problem arises when measuring rotation velocity of a car wheel. The higher the rotation velocity of the wheel is, the lower the accuracy of measurement is. At present, wheel rotation frequency monitoring on roller test benches is carried out by following-up systems. Their sensors are rollers following wheel rotation. The rollers of the system are not kinematically linked to supporting rollers of the test bench. The roller follower is forced against the wheels of the tested vehicle by means of a spring-lever mechanism. Experience of the test bench equipment operation has shown that measurement accuracy is satisfactory at small rates of vehicles diagnosed on roller test benches. With a rising diagnostics rate, rotation velocity measurement errors occur in both braking and pulling modes because a roller spins about a tire tread. The paper shows oscillograms of changes in wheel rotation velocity and rotation velocity measurement system’s signals when testing a vehicle on roller test benches at specified rates.

  5. Rotational motion of an artificial satellite perturbed by solar radiation pressure

    International Nuclear Information System (INIS)

    Moraes, R.V. de; Zanardi, M.C.

    1988-01-01

    The motion of a satellite about its center of mass is studied using a semi-analytical method. Torques produced by conservative and non conservative forces are considered. An analytical model is proposed for solar radiation torques. Andoyer variables are used to describe the rotational motion. Analytical equations are used to transform osculating to a mean set of differential equations. Since the mean equations are more slowly varying, a numerical integration using large step size can be performed to obtain the mean state at a later time. (author) [pt

  6. Discount Rate and Timber Rotation: the Case of Eucalyptus Saligna

    OpenAIRE

    Camilo Restrepo; Mauricio Alviar

    2010-01-01

    Eucalyptus is one of the most important economical and environmental species in Colombia. The main goal of this article is to study the relationship between the discount rate and the year of Eucalyptus Saligna optimal harvest, through the Fisher and Hotelling’s method. The methodology consists of calculating the maximum Net Present Value and performing a sensitivity analysis between the year of harvest and the discount rate. The area of study is located in the eastern region of the state of A...

  7. Differential rotation of the Sun and the Maunder minimum of solar activity

    International Nuclear Information System (INIS)

    Ikhsanov, R.N.; Vitinskij, Yu.I.

    1980-01-01

    Nature of differential rotation of the Sun is discussed. Investigation of long term changes in differential rotation separately for two phase of 11 year cycle of the Sun activity is carried out. Data on heliographic coordinates for every day of all groups of the Sun spots for the years preceding the epoch of the minimum of the 11 year cycle and the Sun groups for the years of maximum from ''Greenwich Photoheliographic Results'' for 1875-1954 are used as initial material. It is shown that differential rotation of the Sun changes in time from one 11 year cycle of the Sun activity to another. This change is connected with the power of 11 year cycle. During the maximum phase of 11 year cycle differentiality of the rotation increases in the cycles where the cycle maximum is higher. Before the minimum of 11 year cycle rotation differentiability is lower in the cycles for which activity maximum is higher in the next 11 year cycle. Equatorial rate of the Sun rotation increases with the decrease in the cycle power when the maximum Wolf number is less than 110. The mentioned regularities took place both during Maunder minimum and before its beginning [ru

  8. Measurement of mean rotation and strain-rate tensors by using stereoscopic PIV

    DEFF Research Database (Denmark)

    Özcan, Oktay; Meyer, Knud Erik; Larsen, Poul Scheel

    2005-01-01

    A technique is described for measuring the mean velocity gradient (rate-of-displacement) tensor by using a conventional stereoscopic particle image velocimetry (SPIV) system. Planar measurement of the mean vorticity vector, rate-of-rotation and rate-of-strain tensors and the production of turbule...

  9. 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.

  10. AN INVESTIGATION OF THE SOURCES OF EARTH-DIRECTED SOLAR WIND DURING CARRINGTON ROTATION 2053

    Energy Technology Data Exchange (ETDEWEB)

    Fazakerley, A. N.; Harra, L. K.; Van Driel-Gesztelyi, L., E-mail: a.fazakerley@ucl.ac.uk [Mullard Space Science Laboratory, University College London (United Kingdom)

    2016-06-01

    In this work we analyze multiple sources of solar wind through a full Carrington Rotation (CR 2053) by analyzing the solar data through spectroscopic observations of the plasma upflow regions and the in situ data of the wind itself. Following earlier authors, we link solar and in situ observations by a combination of ballistic backmapping and potential-field source-surface modeling. We find three sources of fast solar wind that are low-latitude coronal holes. The coronal holes do not produce a steady fast wind, but rather a wind with rapid fluctuations. The coronal spectroscopic data from Hinode ’s Extreme Ultraviolet Imaging Spectrometer show a mixture of upflow and downflow regions highlighting the complexity of the coronal hole, with the upflows being dominant. There is a mix of open and multi-scale closed magnetic fields in this region whose (interchange) reconnections are consistent with the up- and downflows they generate being viewed through an optically thin corona, and with the strahl directions and freeze-in temperatures found in in situ data. At the boundary of slow and fast wind streams there are three short periods of enhanced-velocity solar wind, which we term intermediate based on their in situ characteristics. These are related to active regions that are located beside coronal holes. The active regions have different magnetic configurations, from bipolar through tripolar to quadrupolar, and we discuss the mechanisms to produce this intermediate wind, and the important role that the open field of coronal holes adjacent to closed-field active regions plays in the process.

  11. An Investigation of the Sources of Earth-directed Solar Wind during Carrington Rotation 2053

    Science.gov (United States)

    Fazakerley, A. N.; Harra, L. K.; van Driel-Gesztelyi, L.

    2016-06-01

    In this work we analyze multiple sources of solar wind through a full Carrington Rotation (CR 2053) by analyzing the solar data through spectroscopic observations of the plasma upflow regions and the in situ data of the wind itself. Following earlier authors, we link solar and in situ observations by a combination of ballistic backmapping and potential-field source-surface modeling. We find three sources of fast solar wind that are low-latitude coronal holes. The coronal holes do not produce a steady fast wind, but rather a wind with rapid fluctuations. The coronal spectroscopic data from Hinode’s Extreme Ultraviolet Imaging Spectrometer show a mixture of upflow and downflow regions highlighting the complexity of the coronal hole, with the upflows being dominant. There is a mix of open and multi-scale closed magnetic fields in this region whose (interchange) reconnections are consistent with the up- and downflows they generate being viewed through an optically thin corona, and with the strahl directions and freeze-in temperatures found in in situ data. At the boundary of slow and fast wind streams there are three short periods of enhanced-velocity solar wind, which we term intermediate based on their in situ characteristics. These are related to active regions that are located beside coronal holes. The active regions have different magnetic configurations, from bipolar through tripolar to quadrupolar, and we discuss the mechanisms to produce this intermediate wind, and the important role that the open field of coronal holes adjacent to closed-field active regions plays in the process.

  12. Inertial wave beams and inertial wave modes in a rotating cylinder with time-modulated rotation rate

    Science.gov (United States)

    Borcia, Ion D.; Ghasemi V., Abouzar; Harlander, Uwe

    2014-05-01

    Inertial gravity waves play an crucial role in atmospheres, oceans, and the fluid inside of planets and moons. In the atmosphere, the effect of rotation is neglected for small wavelength and the waves bear the character of internal gravity waves. For long waves, the hydrostatic assumption is made which in turn makes the atmosphere inelastic with respect to inertial motion. In contrast, in the Earth's interior, pure inertial waves are considered as an important fundamental part of the motion. Moreover, as the deep ocean is nearly homogeneous, there the inertial gravity waves bear the character of inertial waves. Excited at the oceans surface mainly due to weather systems the waves can propagate downward and influence the deep oceans motion. In the light of the aforesaid it is important to understand better fundamental inertial wave dynamics. We investigate inertial wave modes by experimental and numerical methods. Inertial modes are excited in a fluid filled rotating annulus by modulating the rotation rate of the outer cylinder and the upper and lower lids. This forcing leads to inertial wave beams emitted from the corner regions of the annulus due to periodic motions in the boundary layers (Klein et al., 2013). When the forcing frequency matches with the eigenfrequency of the rotating annulus the beam pattern amplitude is increasing, the beams broaden and mode structures can be observed (Borcia et al., 2013a). The eigenmodes are compared with analytical solutions of the corresponding inviscid problem (Borcia et al, 2013b). In particular for the pressure field a good agreement can be found. However, shear layers related to the excited wave beams are present for all frequencies. This becomes obvious in particular in the experimental visualizations that are done by using Kalliroscope particles, highlighting relative motion in the fluid. Comparing the eigenfrequencies we find that relative to the analytical frequencies, the experimental and numerical ones show a small

  13. SUNSPOT ROTATION AS A DRIVER OF MAJOR SOLAR ERUPTIONS IN THE NOAA ACTIVE REGION 12158

    Energy Technology Data Exchange (ETDEWEB)

    Vemareddy, P.; Ravindra, B. [Indian Institute of Astrophysics, Koramangala, Bangalore-560034 (India); Cheng, X., E-mail: vemareddy@iiap.res.in [School of Astronomy and Space Science, Nanjing University, Nanjing-210023 (China)

    2016-09-20

    We studied the development conditions of sigmoid structure under the influence of the magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from the Helioseismic Magnetic Imager and coronal EUV observations from the Atmospheric Imaging Assembly reveal that the erupting inverse-S sigmoid had roots at the location of the rotating sunspot. The sunspot rotates at a rate of 0°–5° h{sup −1} with increasing trend in the first half followed by a decrease. The time evolution of many non-potential parameters had a good correspondence with the sunspot rotation. The evolution of the AR magnetic structure is approximated by a time series of force-free equilibria. The non-linear force-free field magnetic structure around the sunspot manifests the observed sigmoid structure. Field lines from the sunspot periphery constitute the body of the sigmoid and those from the interior overlie the sigmoid, similar to a flux rope structure. While the sunspot was rotating, two major coronal mass ejection eruptions occurred in the AR. During the first (second) event, the coronal current concentrations were enhanced (degraded), consistent with the photospheric net vertical current; however, magnetic energy was released during both cases. The analysis results suggest that the magnetic connections of the sigmoid are driven by the slow motion of sunspot rotation, which transforms to a highly twisted flux rope structure in a dynamical scenario. Exceeding the critical twist in the flux rope probably leads to the loss of equilibrium, thus triggering the onset of the two eruptions.

  14. A dissipative model of solar system and stability of stationary rotations

    Science.gov (United States)

    Vilke, V. G.

    2009-04-01

    In classical model of Solar system the planets are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely rigid spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of mass occurs to constant angular velocity. The motion of the centers of mass of spherical planets identically to motion in the appropriate problem of points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the shape: there is "flattening" of a planet in a direction of a vector of its angular velocity and formation of tidal bulgs on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of mass of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates has been obtained. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own rotation of planets, and the small tidal deformations arising under influence of gradients of gravitational forces. The method of division of movements

  15. 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.

  16. Fireball flickering: the case for indirect measurement of meteoroid rotation rates

    Science.gov (United States)

    Beech, Martin; Brown, Peter

    2000-08-01

    Data collected during the Meteorite Observation and Recovery Program (MORP) indicate that 4% of bright fireballs show a periodic variation or flickering in brightness. The observed flickering frequencies vary from a few Hz to as high as 500 Hz. We interpret the flickering phenomenon in terms of meteoroid rotation. The MORP data does not reveal any apparent correlation between the flickering frequency and the properties of the meteoroid or the atmospheric flow conditions under which ablation is taking place. It is argued that the most likely cause of the flickering phenomenon is the rotational modulation of the cross-section area presented by the meteoroid to the on-coming airflow. A study is made of the Peekskill fireball and it is concluded that the meteoroid was spun-up during its long flight through the Earth's atmosphere, and that its initial brake up was due to rotational bursting. We also argue that the Peekskill event provides the best observational evidence that the flickering phenomenon is truly related to the rotation rate of the impinging meteoroid. We find that the observed rotation rates of the MORP fireballs are clustered just below the allowed limit set by rotational bursting, but argue that this is due to an observational selection effect that mitigates against the detection of low-frequency flickering.

  17. Internal Flow of Contra-Rotating Small Hydroturbine at Off- Design Flow Rates

    Science.gov (United States)

    SHIGEMITSU, Toru; TAKESHIMA, Yasutoshi; OGAWA, Yuya; FUKUTOMI, Junichiro

    2016-11-01

    Small hydropower generation is one of important alternative energy, and enormous potential lie in the small hydropower. However, efficiency of small hydroturbines is lower than that of large one. Then, there are demands for small hydroturbines to keep high performance in wide flow rate range. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance. In this research, performance of the contra-rotating small hydroturbine with 60mm casing diameter was investigated by an experiment and numerical analysis. Efficiency of the contra-rotating small hydroturbine was high in pico-hydroturbine and high efficiency could be kept in wide flow rate range, however the performance of a rear rotor decreased significantly in partial flow rates. Then, internal flow condition, which was difficult to measure experimentally, was investigated by the numerical flow analysis. Then, a relation between the performance and internal flow condition was considered by the numerical analysis result.

  18. Solar influence on meteor rates and atmospheric density variations at meteor heights

    International Nuclear Information System (INIS)

    Ellyett, C.

    1977-01-01

    A full analysis of radar-determined meteor rates from New Zealand, involving 3,085,574 meteors recorded over a total of 3 1/2 years, and 12,391,976 meteors recorded by the National Research Council of Canada in 8 1/2 years confirms an inverse relationship between meteor rates and solar activity as measured by sunspot numbers. The relationship, significant at the 1% level, appears in the Canadian annual average when the abnormal 1963 increase is removed, in monthly and 1/3-monthly results for the total Canadian period, and in monthly intervals for 1 year of the New Zealand data. This proven relationship of meteor rates with the solar cycle calls for a significant density gradient change over the solar cycle in the 70- to-120-km height range. Although some definite negative results have been reported, no unambiguous positive results are yet available supporting such a density gradient change. It is possible that density variations due to annual, semiannual, diurnal, and latitudinal changes obscure any 11-year density gradient change occurring at these heights. It is uncertain whether the 1963 increase represents density gradient changes in the meteor ablation region regularly brought about 1-2 years before each sunspot minimum or is a special event due to volcanic dust. The following additional facts have emerged from the present analysis. (1) Within a 1-year period the seasonal rate change of astronomical origin overrides any density gradient change in controlling the meteor rates in one of the two hemispheres. (2) The earth's daily rotation alters rates in phase with probable diurnal density gradient changes. (3) An effect due to D region absorption has been observed in the Canadian data

  19. Atmospheric solar heating rate in the water vapor bands

    Science.gov (United States)

    Chou, Ming-Dah

    1986-01-01

    The total absorption of solar radiation by water vapor in clear atmospheres is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are computed for individual absorption bands and for the total near-infrared region. The parameterization is based upon monochromatic calculations and follows essentially the scaling approximation of Chou and Arking, but the effect of temperature variation with height is taken into account in order to enhance the accuracy. Furthermore, the spectral range is extended to cover the two weak bands centered at 0.72 and 0.82 micron. Comparisons with monochromatic calculations show that the atmospheric heating rate and the surface radiation can be accurately computed from the parameterization. Comparisons are also made with other parameterizations. It is found that the absorption of solar radiation can be computed reasonably well using the Goody band model and the Curtis-Godson approximation.

  20. Detection and Modeling of Non-Tidal Oceanic Effects on the Earth's Rotation Rate

    Science.gov (United States)

    Marcus, S. L.; Chao, Y.; Dickey, J. O.; Gegout, P.

    1998-01-01

    Sub-decadal changes in the Earth's rotation rate, and hence in the length-of-day (LOD), are largely controlled by variations in atmospheric angular momentum. Results from two oceanic general circulation models (OGCMs), forced by observed wind stress and heat flux for the years 1992-1994, show that ocean current and mass distribution changes also induce detectable LOD variations.

  1. Simple analytical approximation for rotationally inelastic rate constants based on the energy corrected sudden scaling law

    International Nuclear Information System (INIS)

    Smith, N.; Pritchard, D.E.

    1981-01-01

    We have recently demonstrated that the energy corrected sudden (ECS) scaling law of De Pristo et al. when conbined with the power law assumption for the basis rates k/sub l/→0proportional[l(l+1)]/sup -g/ can accurately fit a wide body of rotational energy transfer data. We develop a simple and accurate approximation to this fitting law, and in addition mathematically show the connection between it and our earlier proposed energy based law which also has been successful in describing both theoretical and experimental data on rotationally inelastic collisions

  2. Does nitrogen fertilizer application rate to corn affect nitrous oxide emissions from the rotated soybean crop?

    Science.gov (United States)

    Iqbal, Javed; Mitchell, David C; Barker, Daniel W; Miguez, Fernando; Sawyer, John E; Pantoja, Jose; Castellano, Michael J

    2015-05-01

    Little information exists on the potential for N fertilizer application to corn ( L.) to affect NO emissions during subsequent unfertilized crops in a rotation. To determine if N fertilizer application to corn affects NO emissions during subsequent crops in rotation, we measured NO emissions for 3 yr (2011-2013) in an Iowa, corn-soybean [ (L.) Merr.] rotation with three N fertilizer rates applied to corn (0 kg N ha, the recommended rate of 135 kg N ha, and a high rate of 225 kg N ha); soybean received no N fertilizer. We further investigated the potential for a winter cereal rye ( L.) cover crop to interact with N fertilizer rate to affect NO emissions from both crops. The cover crop did not consistently affect NO emissions. Across all years and irrespective of cover crop, N fertilizer application above the recommended rate resulted in a 16% increase in mean NO flux rate during the corn phase of the rotation. In 2 of the 3 yr, N fertilizer application to corn (0-225 kg N ha) did not affect mean NO flux rates from the subsequent unfertilized soybean crop. However, in 1 yr after a drought, mean NO flux rates from the soybean crops that received 135 and 225 kg N ha N application in the corn year were 35 and 70% higher than those from the soybean crop that received no N application in the corn year. Our results are consistent with previous studies demonstrating that cover crop effects on NO emissions are not easily generalizable. When N fertilizer affects NO emissions during a subsequent unfertilized crop, it will be important to determine if total fertilizer-induced NO emissions are altered or only spread across a greater period of time. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. The Dependence of Tropical Cyclone Count and Size on Rotation Rate

    Science.gov (United States)

    Chavas, D. R.; Reed, K. A.

    2017-12-01

    Both theory and idealized equilibrium modeling studies indicate that tropical cyclone size decreases with background rotation rate. In contrast, in real-world observations size tends to increase with latitude. Here we seek to resolve this apparent contradiction via a set of reduced-complexity global aquaplanet simulations with varying planetary rotation rates using the NCAR Community Atmosphere Model 5. The latitudinal distribution of both storm count and size are found to vary markedly with rotation rate, yielding insight into the dynamical constraints on tropical cyclone activity on a rotating planet. Moreover, storm size is found to vary non-monotonically with latitude, indicating that non-equilibrium effects are crucial to the life-cycle evolution of size in nature. Results are then compared to experiments in idealized, time-dependent limited-area modeling simulations using CM1 in axisymmetric and three-dimensional geometry. Taken together, this hierarchy of models is used to quantify the role of equilibrium versus transient controls on storm size and the relevance of each to real storms in nature.

  4. False negative rate of syndesmotic injury in pronation-external rotation stage IV ankle fractures

    Directory of Open Access Journals (Sweden)

    Kwang-Soon Song

    2013-01-01

    Full Text Available Background: To investigate false negative rate in the diagnosis of diastasis on initial static anteroposterior radiograph and reliability of intraoperative external rotational stress test for detection of concealed disruption of syndesmosis in pronation external rotation (PER stage IV (Lauge-Hansen ankle fractures. Materials and Methods: We prospectively studied 34 PER stage IV ankle fractures between September 2001 and September 2008. Twenty (59% patients show syndesmotic injury on initial anteroposterior radiographs. We performed an intraoperative external rotation stress test in other 14 patients with suspicious PER stage IV ankle fractures, which showed no defined syndesmotic injury on anteroposterior radiographs inspite of a medial malleolar fracture, an oblique fibular fracture above the syndesmosis and fracture of the posterior tubercle of the tibia. Results: All 14 fractures showed different degrees of tibiofibular clear space (TFCS and tibiofibular overlapping (TFO on the external rotation stress test radiograph compared to the initial plain anteroposterior radiograph. It is important to understand the fracture pattern characterstic of PER stage IV ankle fractures even though it appears normal on anteroposterior radiographs, it is to be confirmed for the concealed syndesmotic injury through a routine intraoperative external rotational stress radiograph.

  5. Increasing age and tear size reduce rotator cuff repair healing rate at 1 year.

    Science.gov (United States)

    Rashid, Mustafa S; Cooper, Cushla; Cook, Jonathan; Cooper, David; Dakin, Stephanie G; Snelling, Sarah; Carr, Andrew J

    2017-12-01

    Background and purpose - There is a need to understand the reasons why a high proportion of rotator cuff repairs fail to heal. Using data from a large randomized clinical trial, we evaluated age and tear size as risk factors for failure of rotator cuff repair. Patients and methods - Between 2007 and 2014, 65 surgeons from 47 hospitals in the National Health Service (NHS) recruited 447 patients with atraumatic rotator cuff tendon tears to the United Kingdom Rotator Cuff Trial (UKUFF) and 256 underwent rotator cuff repair. Cuff integrity was assessed by imaging in 217 patients, at 12 months post-operation. Logistic regression analysis was used to determine the influence of age and intra-operative tear size on healing. Hand dominance, sex, and previous steroid injections were controlled for. Results - The overall healing rate was 122/217 (56%) at 12 months. Healing rate decreased with increasing tear size (small tears 66%, medium tears 68%, large tears 47%, and massive tears 27% healed). The mean age of patients with a healed repair was 61 years compared with 64 years for those with a non-healed repair. Mean age increased with larger tear sizes (small tears 59 years, medium tears 62 years, large tears 64 years, and massive tears 66 years). Increasing age was an independent factor that negatively influenced healing, even after controlling for tear size. Only massive tears were an independent predictor of non-healing, after controlling for age. Interpretation - Although increasing age and larger tear size are both risks for failure of rotator cuff repair healing, age is the dominant risk factor.

  6. 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.

  7. Transient rotation of photospheric vector magnetic fields associated with a solar flare.

    Science.gov (United States)

    Xu, Yan; Cao, Wenda; Ahn, Kwangsu; Jing, Ju; Liu, Chang; Chae, Jongchul; Huang, Nengyi; Deng, Na; Gary, Dale E; Wang, Haimin

    2018-01-03

    As one of the most violent eruptions on the Sun, flares are believed to be powered by magnetic reconnection. The fundamental physics involving the release, transfer, and deposition of energy have been studied extensively. Taking advantage of the unprecedented resolution provided by the 1.6 m Goode Solar Telescope, here, we show a sudden rotation of vector magnetic fields, about 12-20° counterclockwise, associated with a flare. Unlike the permanent changes reported previously, the azimuth-angle change is transient and cospatial/temporal with Hα emission. The measured azimuth angle becomes closer to that in potential fields suggesting untwist of flare loops. The magnetograms were obtained in the near infrared at 1.56 μm, which is minimally affected by flare emission and no intensity profile change was detected. We believe that these transient changes are real and discuss the possible explanations in which the high-energy electron beams or Alfve'n waves play a crucial role.

  8. Simultaneously photocatalytic treatment of hexavalent chromium (Cr(VI)) and endocrine disrupting compounds (EDCs) using rotating reactor under solar irradiation

    International Nuclear Information System (INIS)

    Kim, Youngji; Joo, Hyunku; Her, Namguk; Yoon, Yeomin; Sohn, Jinsik; Kim, Sungpyo; Yoon, Jaekyung

    2015-01-01

    Highlights: • Self-rotating reactor including TiO 2 NTs is applied under solar irradiation. • Simultaneously photocatalysis of Cr(VI) and EDCs is observed to be up to 95%. • Photocatalytic reactions of Cr(VI) and EDCs are favorable under acidic pH. • Charge interaction and hole scavenge between TiO 2 and pollutants are synergy factors. - Abstract: In this study, simultaneous treatments, reduction of hexavalent chromium (Cr(VI)) and oxidation of endocrine disrupting compounds (EDCs), such as bisphenol A (BPA), 17α-ethinyl estradiol (EE2) and 17β-estradiol (E2), were investigated with a rotating photocatalytic reactor including TiO 2 nanotubes formed on titanium mesh substrates under solar UV irradiation. In the laboratory tests with a rotating type I reactor, synergy effects of the simultaneous photocatalytic reduction and oxidation of inorganic (Cr(VI)) and organic (BPA) pollutants were achieved. Particularly, the concurrent photocatalytic reduction of Cr(VI) and oxidation of BPA was higher under acidic conditions. The enhanced reaction efficiency of both pollutants was attributed to a stronger charge interaction between TiO 2 nanotubes (positive charge) and the anionic form of Cr(VI) (negative charge), which are prevented recombination (electron–hole pair) by the hole scavenging effect of BPA. In the extended outdoor tests with a rotating type II reactor under solar irradiation, the experiment was extended to examine the simultaneous reduction of Cr(VI) in the presence of additional EDCs, such as EE2 and E2 as well as BPA. The findings showed that synergic effect of both photocatalytic reduction and oxidation was confirmed with single-component (Cr(VI) only), two-components (Cr(VI)/BPA, Cr(VI)/EE2, and Cr(VI)/E2), and four-components (Cr(VI)/BPA/EE2/E2) under various solar irradiation conditions

  9. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  10. The impact of changing solar screen rotation angle and its opening aspect ratios on Daylight Availability in residential desert buildings

    KAUST Repository

    Sherif, Ahmed H.

    2012-11-01

    In desert sunny clear-sky regions solar penetration can become excessive. This can cause non-uniform daylight distribution, glare and high solar heat gain, affecting both visual and thermal comfort. Shading devices, such as solar screens, were usually used to diffuse and prevent direct solar penetration into spaces. This paper investigates the impact of changing solar screen axial rotation angle and screen opening aspect ratio on daylighting performance in a typical residential living room space under the desert sunny clear-sky. The larger aim is to arrive at efficient solar screen designs that suit the different orientations.The study was divided into three consecutive phases. In phase one, the effect of the two parameters on Daylight Availability was tested. The solar screen was axially rotated by three different angles at 10° increments. Also, the aspect ratio of the screen opening in both horizontal and vertical directions was changed systematically. Simulation was conducted using the annual Daylight Dynamic Performance Metrics (DDPMs). In phase two, the Annual Daylight Glare Probability (DGP) metric was evaluated for the cases that were found adequate in phase one. In the third phase, the annual solar energy transmittance through the screen was calculated for the cases that achieved acceptable performance in the two previous phases in order to identify the more energy efficient screens.Solar screens with openings having horizontal aspect ratios were found to be the most effective, while those with vertical aspect ratios were achieved the lowest performance. In the North orientation, since almost all the cases that were tested in this research provided acceptable daylighting performance, the designer now have a variety of options to choose from. Preference should be given to screen openings of horizontal aspect ratios, especially the 12:1 and 18:1 (H:V) screens that achieved the best performance where 92% of the space was " daylit" in comparison with only 53

  11. Increasing FSW join strength by optimizing feed rate, rotating speed and pin angle

    Science.gov (United States)

    Darmadi, Djarot B.; Purnowidodo, Anindito; Siswanto, Eko

    2017-10-01

    Principally the join in Friction Stir Welding (FSW) is formed due to mechanical bonding. At least there are two factors determines the quality of this join, first is the temperature in the area around the interface and secondly the intense of mixing forces in nugget zone to create the mechanical bonding. The adequate temperature creates good flowability of the nugget zone and an intensive mixing force produces homogeneous strong bonding. Based on those two factors in this research the effects of feed rate, rotating speed and pin angle of the FSW process to the tensile strength of resulted join are studied. The true experimental method was used. Feed rate was varied at 24, 42, 55 and 74 mm/minutes and from the experimental results, it can be concluded that the higher feed rate decreases the tensile strength of weld join and it is believed due to the lower heat embedded in the material. Inversely, the higher rotating speed increases the join’s tensile strength as a result of higher heat embedded in base metal and higher mixing force in the nugget zone. The rotating speed were 1842, 2257 and 2904 RPMs. The pin angle determines the direction of mixing force. With variation of pin angle: 0°, 4°, 8° and 12° the higher pin angle generally increases the tensile strength because of more intensive mixing force. For 12° pin angle the lower tensile strength is found since the force tends to push out the nugget area from the joint gap.

  12. A Reuse Evaluation for Solar-Cell Silicon Wafers via Shift Revolution and Tool Rotation Using Magnetic Assistance in Ultrasonic Electrochemical Micromachining

    Directory of Open Access Journals (Sweden)

    P. S. Pa

    2013-01-01

    Full Text Available A new reuse fabrication using a tool module with rotation and revolution through a process of magnetic assistance in ultrasonic electrochemical micromachining (UEMM for removal of the surface layers from silicon wafers of solar cells is demonstrated. The target of the proposed reuse fabrication method is to replace the current approach, which uses strong acid and grinding and may damage the physical structure of silicon wafers and pollute to the environment. A precisely engineered clean production approach to removal of surface microstructure layers from silicon wafers is to develop a mass production system for recycling defective or discarded silicon wafers of solar cells that can reduce pollution and cost. The high revolution speed of the shift with the high rotation speed of the designed tool increases the discharge mobility and improves the removal effect associated with the high feed rate of the workpiece. High frequency and high power of ultrasonic with large electrolyte flow rate and high magnetic strengths with a small distance between the two magnets provide a large discharge effect and good removal; only a short period of time is required to remove the epoxy film and Si3N4 layer easily and cleanly.

  13. Resonance of about-weekly human heart rate rhythm with solar activity change.

    Science.gov (United States)

    Cornelissen, G; Halberg, F; Wendt, H W; Bingham, C; Sothern, R B; Haus, E; Kleitman, E; Kleitman, N; Revilla, M A; Revilla, M; Breus, T K; Pimenov, K; Grigoriev, A E; Mitish, M D; Yatsyk, G V; Syutkina, E V

    1996-12-01

    In several human adults, certain solar activity rhythms may influence an about 7-day rhythm in heart rate. When no about-weekly feature was found in the rate of change in sunspot area, a measure of solar activity, the double amplitude of a circadian heart rate rhythm, approximated by the fit of a 7-day cosine curve, was lower, as was heart rate corresponds to about-weekly features in solar activity and/or relates to a sunspot cycle.

  14. State resolved rotational excitation cross-sections and rates in H2 + H2 collisions

    International Nuclear Information System (INIS)

    Sultanov, Renat A.; Guster, Dennis

    2006-01-01

    Rotational transitions in molecular hydrogen collisions are computed. The two most recently developed potential energy surfaces for the H 2 -H 2 system are used from the following works: [A.I. Boothroyd, P.G. Martin, W.J. Keogh, M.J. Peterson, J. Chem. Phys., 116 (2002) 666; P. Diep, J.K. Johnson, J. Chem. Phys., 113 (2000) 3480; P. Diep, J.K. Johnson, J. Chem. Phys., 112 (2000) 4465]. Cross-sections for rotational transitions 00 → 20, 22, 40, 42, 44 and corresponding rate coefficients are calculated using a quantum-mechanical approach. Results are compared for a wide range of kinetic temperatures 300 K ≤ T≤ 3000 K

  15. Factors affecting healing rates after arthroscopic double-row rotator cuff repair.

    Science.gov (United States)

    Tashjian, Robert Z; Hollins, Anthony M; Kim, Hyun-Min; Teefey, Sharlene A; Middleton, William D; Steger-May, Karen; Galatz, Leesa M; Yamaguchi, Ken

    2010-12-01

    Double-row arthroscopic rotator cuff repairs were developed to improve initial biomechanical strength of repairs to improve healing rates. Despite biomechanical improvements, failure of healing remains a clinical problem. To evaluate the anatomical results after double-row arthroscopic rotator cuff repair with ultrasound to determine postoperative repair integrity and the effect of various factors on tendon healing. Case series; Level of evidence, 4. Forty-eight patients (49 shoulders) who had a complete arthroscopic rotator cuff repair (double-row technique) were evaluated with ultrasound at a minimum of 6 months after surgery. Outcome was evaluated at a minimum of 1-year follow-up with standardized history and physical examination, visual analog scale for pain, active forward elevation, and preoperative and postoperative shoulder scores according to the system of the American Shoulder and Elbow Surgeons and the Simple Shoulder Test. Quantitative strength was measured postoperatively. Ultrasound and physical examinations were performed at a minimum of 6 months after surgery (mean, 16 months; range, 6 to 36 months) and outcome questionnaire evaluations at a minimum of 12 months after surgery (mean, 29 months; range, 12 to 55 months). Of 49 repairs, 25 (51%) were healed. Healing rates were 67% in single-tendon tears (16 of 24 shoulders) and 36% in multitendon tears (9 of 25 shoulders). Older age and longer duration of follow-up were correlated with poorer tendon healing (P repair (P rotator cuff repair. The biological limitation at the repair site, as reflected by the effects of age on healing, appears to be the most important factor influencing tendon healing, even after maximizing repair biomechanical strength with a double-row construct.

  16. Predicting Ionization Rates from SEP and Solar Wind Proton Precipitation into the Martian Atmosphere

    Science.gov (United States)

    Jolitz, R.; Dong, C.; Lee, C. O.; Curry, S.; Lillis, R. J.; Brain, D.; Halekas, J. S.; Larson, D. E.; Bougher, S. W.; Jakosky, B. M.

    2017-12-01

    Precipitating energetic particles ionize planetary atmospheres and increase total electron content. At Mars, the solar wind and solar energetic particles (SEPs) can precipitate directly into the atmosphere because solar wind protons can charge exchange to become neutrals and pass through the magnetosheath, while SEPs are sufficiently energetic to cross the magnetosheath unchanged. In this study we will present predicted ionization rates and resulting electron densities produced by solar wind and SEP proton ionization during nominal solar activity and a CME shock front impact event on May 16 2016. We will use the Atmospheric Scattering of Protons and Energetic Neutrals (ASPEN) model to compare ionization by SEP and solar wind protons currently measured by the SWIA (Solar Wind Ion Analyzer) and SEP instruments aboard the MAVEN spacecraft. Results will help to quantify how the ionosphere responds to extreme solar events during solar minimum.

  17. Investigations on efficiencies of HT solar collectors for different flow rates and collector tilts

    DEFF Research Database (Denmark)

    Chen, Ziqian; Perers, Bengt; Furbo, Simon

    2013-01-01

    Two HT solar collectors for solar heating plants from Arcon Solvarme A/S are tested in a laboratory test facility for solar collectors at Technical University of Denmark (DTU). The collectors are designed in the same way. However, one solar collector is equipped with an ETFE foil between the abso......Two HT solar collectors for solar heating plants from Arcon Solvarme A/S are tested in a laboratory test facility for solar collectors at Technical University of Denmark (DTU). The collectors are designed in the same way. However, one solar collector is equipped with an ETFE foil between...... the absorber and the cover glass and the other is without ETFE foil. The efficiencies for the collectors are tested at different flow rates and tilt. On the basis of the measured efficiencies, the efficiencies for the collectors as functions of flow rates are obtained. The calculated efficiencies are in good...

  18. Calibrationless rotating Lorentz-force flowmeters for low flow rate applications

    Science.gov (United States)

    Hvasta, M. G.; Dudt, D.; Fisher, A. E.; Kolemen, E.

    2018-07-01

    A ‘weighted magnetic bearing’ has been developed to improve the performance of rotating Lorentz-force flowmeters (RLFFs). Experiments have shown that the new bearing reduces frictional losses within a double-sided, disc-style RLFF to negligible levels. Operating such an RLFF under ‘frictionless’ conditions provides two major benefits. First, the steady-state velocity of the RLFF magnets matches the average velocity of the flowing liquid at low flow rates. This enables an RLFF to make accurate volumetric flow measurements without any calibration or prior knowledge of the fluid properties. Second, due to minimized frictional losses, an RLFF is able to measure low flow rates that cannot be detected when conventional, high-friction bearings are used. This paper provides a brief background on RLFFs, gives a detailed description of weighted magnetic bearings, and compares experimental RLFF data to measurements taken with a commercially available flowmeter.

  19. Recommendations for the performance rating of flat plate terrestrial photovoltaic solar panels

    Science.gov (United States)

    Treble, F. C.

    1976-01-01

    A review of recommendations for standardizing the performance rating of flat plate terrestrial solar panels is given to develop an international standard code of practice for performance rating. Required data to characterize the performance of a solar panel are listed. Other items discussed are: (1) basic measurement procedures; (2) performance measurement in natural sunlight and simulated sunlight; (3) standard solar cells; (4) the normal incidence method; (5) global method and (6) definition of peak power.

  20. Healing rates for challenging rotator cuff tears utilizing an acellular human dermal reinforcement graft

    Science.gov (United States)

    Agrawal, Vivek

    2012-01-01

    Purpose: This study presents a retrospective case series of the clinical and structural outcomes (1.5 T MRI) of arthroscopic rotator cuff repair with acellular human dermal graft reinforcement performed by a single surgeon in patients with large, massive, and previously repaired rotator cuff tears. Materials and Methods: Fourteen patients with mean anterior to posterior tear size 3.87 ± 0.99 cm (median 4 cm, range 2.5–6 cm) were enrolled in the study and were evaluated for structural integrity using a high-field (1.5 T) MRI at an average of 16.8 months after surgery. The Constant-Murley scores, the Flexilevel Scale of Shoulder Function (Flex SF), scapular plane abduction, and strength were analyzed. Results: MRI results showed that the rotator cuff repair was intact in 85.7% (12/14) of the patients studied. Two patients had a Sugaya Type IV recurrent tear (2 of 14; 14.3%), which were both less than 1 cm. The Constant score increased from a preoperative mean of 49.72 (range 13–74) to a postoperative mean of 81.07 (range 45–92) (P value = 0.009). Flexilevel Scale of Shoulder Function (Flex SF) Score normalized to a 100-point scale improved from a preoperative mean of 53.69 to a postoperative mean of 79.71 (P value = 0.003). The Pain Score improved from a preoperative mean of 7.73 to a postoperative mean of 13.57 (P value = 0.008). Scapular plane abduction improved from a preoperative mean of 113.64° to a postoperative mean of 166.43° (P value = 0.010). The strength subset score improved from a preoperative mean of 1.73 kg to a postoperative mean of 7.52 kg (P value = 0.006). Conclusions: This study presents a safe and effective technique that may help improve the healing rates of large, massive, and revision rotator cuff tears with the use of an acellular human dermal allograft. This technique demonstrated favorable structural healing rates and statistically improved functional outcomes in the near term. Level of Evidence: 4. Retrospective case series. PMID

  1. Spinning rate decay of levitated high-Tc superconductors in rotational magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Terentiev, A.N.; Kutukova, E.O.; Kuznetsov, A.A. (Inst. of Chemical Physics, Academy of Sciences, Moscow (Russia)); Mozhaev, A.P. (Moscow State Univ., Dept. of Chemistry (Russia))

    1992-04-01

    The rotation damping of a levitated superconductor was examined in the static field of a ring-shaped magnet and in the rotating field of coils. It was demonstrated that the pinning force mainly contributed to magnetic friction while the influence of a viscous component was negligible. The rotating magnetic field created a torque, reducing the angular deceleration under relaxation. Dependence of the rotational field-induced torque on the field-intensity was step-like. A relationship between the step-like behavior of rotational field-induced torque and pinning center distribution is discussed. The origins of friction torque and rotational field-produced torque are discussed. (orig.).

  2. Dynamic strain and rotation ground motions of the 2011 Tohoku earthquake from dense high-rate GPS observations in Taiwan

    Science.gov (United States)

    Huang, B. S.; Rau, R. J.; Lin, C. J.; Kuo, L. C.

    2017-12-01

    Seismic waves generated by the 2011 Mw 9.0 Tohoku, Japan earthquake were well recorded by continuous GPS in Taiwan. Those GPS were operated in one hertz sampling rate and densely distributed in Taiwan Island. Those continuous GPS observations and the precise point positioning technique provide an opportunity to estimate spatial derivatives from absolute ground motions of this giant teleseismic event. In this study, we process and investigate more than one and half hundred high-rate GPS displacements and its spatial derivatives, thus strain and rotations, to compare to broadband seismic and rotational sensor observations. It is shown that continuous GPS observations are highly consistent with broadband seismic observations during its surface waves across Taiwan Island. Several standard Geodesy and seismic array analysis techniques for spatial gradients have been applied to those continuous GPS time series to determine its dynamic strain and rotation time histories. Results show that those derivate GPS vertical axis ground rotations are consistent to seismic array determined rotations. However, vertical rotation-rate observations from the R1 rotational sensors have low resolutions and could not compared with GPS observations for this special event. For its dese spatial distribution of GPS stations in Taiwan Island, not only wavefield gradient time histories at individual site was obtained but also 2-D spatial ground motion fields were determined in this study also. In this study, we will report the analyzed results of those spatial gradient wavefields of the 2011 Tohoku earthquake across Taiwan Island and discuss its geological implications.

  3. A rapid decrease in the rotation rate of comet 41P/Tuttle-Giacobini-Kresák.

    Science.gov (United States)

    Bodewits, Dennis; Farnham, Tony L; Kelley, Michael S P; Knight, Matthew M

    2018-01-10

    Cometary outgassing can produce torques that change the spin state of the cometary nucleus, which in turn influences the evolution and lifetime of the comet. If these torques increase the rate of rotation to the extent that centripetal forces exceed the material strength of the nucleus, the comet can fragment. Torques that slow down the rotation can cause the spin state to become unstable, but if the torques persist the nucleus can eventually reorient itself and the rotation rate can increase again. Simulations predict that most comets go through a short phase of rapid changes in spin state, after which changes occur gradually over longer times. Here we report observations of comet 41P/Tuttle-Giacobini-Kresák during its close approach to Earth (0.142 astronomical units, approximately 21 million kilometres, on 1 April 2017) that reveal a rapid decrease in rotation rate. Between March and May 2017, the apparent rotation period of the nucleus increased from 20 hours to more than 46 hours-a rate of change of more than an order of magnitude larger than has hitherto been measured. This phenomenon must have been caused by the gas emission from the comet aligning in such a way that it produced an anomalously strong torque that slowed the spin rate of the nucleus. The behaviour of comet 41P/Tuttle-Giacobini-Kresák suggests that it is in a distinct evolutionary state and that its rotation may be approaching the point of instability.

  4. A rapid decrease in the rotation rate of comet 41P/Tuttle–Giacobini–Kresák

    Science.gov (United States)

    Bodewits, Dennis; Farnham, Tony L.; Kelley, Michael S. P.; Knight, Matthew M.

    2018-01-01

    Cometary outgassing can produce torques that change the spin state of the cometary nucleus, which in turn influences the evolution and lifetime of the comet. If these torques increase the rate of rotation to the extent that centripetal forces exceed the material strength of the nucleus, the comet can fragment. Torques that slow down the rotation can cause the spin state to become unstable, but if the torques persist the nucleus can eventually reorient itself and the rotation rate can increase again. Simulations predict that most comets go through a short phase of rapid changes in spin state, after which changes occur gradually over longer times. Here we report observations of comet 41P/Tuttle–Giacobini–Kresák during its close approach to Earth (0.142 astronomical units, approximately 21 million kilometres, on 1 April 2017) that reveal a rapid decrease in rotation rate. Between March and May 2017, the apparent rotation period of the nucleus increased from 20 hours to more than 46 hours—a rate of change of more than an order of magnitude larger than has hitherto been measured. This phenomenon must have been caused by the gas emission from the comet aligning in such a way that it produced an anomalously strong torque that slowed the spin rate of the nucleus. The behaviour of comet 41P/Tuttle–Giacobini–Kresák suggests that it is in a distinct evolutionary state and that its rotation may be approaching the point of instability.

  5. Retear rate in the late postoperative period after arthroscopic rotator cuff repair.

    Science.gov (United States)

    Kim, Jae Hwa; Hong, In Tae; Ryu, Keun Jung; Bong, Sun Tae; Lee, Yoon Seok; Kim, Jang Hwan

    2014-11-01

    Few clinical studies have evaluated the integrity of repaired tendons and identified the timing of retears through the use of serial imaging. Retears after arthroscopic rotator cuff repair are uncommon in the late postoperative period (after 3 months). Case series; Level of evidence, 4. Among 221 arthroscopic rotator cuff repairs that were performed at a single hospital between May 2010 and February 2012, 61 were involved in this study. Rotator cuff tears consisted of 12 small, 31 medium, 8 large, and 6 massive rotator cuff tears. Additionally, 4 isolated subscapularis tears were included. For clinical evaluation, all patients were assessed both preoperatively and postoperatively by use of the University of California-Los Angeles Shoulder Rating Scale, absolute and relative Constant scores, and American Shoulder and Elbow Surgeons score; active range of motion was assessed as well. For radiological evaluation, all 61 patients had a magnetic resonance imaging (MRI) evaluation at 3 months postoperatively. Among them, 23 patients were evaluated for repaired tendon integrity on postoperative MRI at a minimum of 1 year after surgery (mean, 14.1 months; range, 12-19 months), and results were classified according to the Sugaya classification: type I, sufficient thickness with homogeneously low intensity on each image; type II, sufficient thickness, partial high-intensity area; type III, less than half the thickness without discontinuity; type IV, minor discontinuity; and type V, major discontinuity. The remaining 38 patients, who refused to undergo MRI again for financial reasons, were evaluated through ultrasound. Statistically significant clinical improvements were observed after surgery. The MRI conducted at 3 months postoperatively identified 9 patients with Sugaya type I, 28 patients with type II, and 24 patients with type III repairs. No patients showed Sugaya type IV or V repairs at postoperative 3 months. Thirty-seven patients who had shown Sugaya type I or II

  6. Effects of solar collecting area and water flow rate on the performance of a sand bed solar collector

    International Nuclear Information System (INIS)

    Maganhar, A.L.; Memon, A.H.; Panhwar, M.I.

    2005-01-01

    The often discussed renewable sources of energy have been great interest to energy researchers and planners for quite some time. The primary of renewing all sources of energy is the sun. There have been two main problems not yet fully resolved. One is the large scale production of energy and other is the cost factor. In the present study, the cost factor is under consideration. In this regard a non-conventional solar collector using indigenous material (pit sand) as solar absorber is designed and manufactured. This paper presents the results of an investigation of the effect of solar collecting area and water flow rate on the performance of a pit sand bed solar collector especially in terms of rise in water temperature. Three pit sand solar collectors of area 1m/sup 2/ each were connected in series to enhance the collecting area and the system was tested for different flow rates. Experimental results proved that there was increase in water temperature with increase in solar collecting area an decreases in water temperature with increase in flow rate. (author)

  7. 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.

  8. Temporal flow instability for Magnus-Robins effect at high rotation rates

    Science.gov (United States)

    Sengupta, T. K.; Kasliwal, A.; de, S.; Nair, M.

    2003-06-01

    The lift and drag coefficients of a circular cylinder, translating and spinning at a supercritical rate is studied theoretically to explain the experimentally observed violation of maximum mean lift coefficient principle, that was proposed heuristically by Prandtl on the basis of inviscid flow model. It is also noted experimentally that flow past a rotating and translating cylinder experiences temporal instability-a fact not corroborated by any theoretical studies so far. In the present paper we report very accurate solution of Navier-Stokes equation that displays the above-mentioned instability and the violation of the maximum limit. The calculated lift coefficient exceeds the limit of /4π, instantaneously as well as in time-averaged sense. The main purpose of the present paper is to explain the observed temporal instability sequence in terms of a new theory of instability based on full Navier-Stokes equation that does not require making any assumption about the flow field, unlike other stability theories.

  9. Steady thermal stress and strain rates in a rotating circular cylinder under steady state temperature

    Directory of Open Access Journals (Sweden)

    Pankaj Thakur

    2014-01-01

    Full Text Available Thermal stress and strain rates in a thick walled rotating cylinder under steady state temperature has been derived by using Seth’s transition theory. For elastic-plastic stage, it is seen that with the increase of temperature, the cylinder having smaller radii ratios requires lesser angular velocity to become fully plastic as compared to cylinder having higher radii ratios The circumferential stress becomes larger and larger with the increase in temperature. With increase in thickness ratio stresses must be decrease. For the creep stage, it is seen that circumferential stresses for incompressible materials maximum at the internal surface as compared to compressible material, which increase with the increase in temperature and measure n.

  10. A SOLAR TORNADO OBSERVED BY AIA/SDO: ROTATIONAL FLOW AND EVOLUTION OF MAGNETIC HELICITY IN A PROMINENCE AND CAVITY

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xing; Morgan, Huw; Leonard, Drew; Jeska, Lauren, E-mail: xxl@aber.ac.uk [Sefydliad Mathemateg a Ffiseg, Prifysgol Aberystwyth, Ceredigion, Cymru SY23 3BZ (United Kingdom)

    2012-06-20

    During 2011 September 24, as observed by the Atmospheric Imaging Assembly instrument of the Solar Dynamic Observatory and ground-based H{alpha} telescopes, a prominence and associated cavity appeared above the southwest limb. On 2011 September 25 8:00 UT, material flows upward from the prominence core along a narrow loop-like structure, accompanied by a rise ({>=}50,000 km) of the prominence core and the loop. As the loop fades by 10:00, small blobs and streaks of varying brightness rotate around the top part of the prominence and cavity, mimicking a cyclone. The most intense and coherent rotation lasts for over three hours, with emission in both hot ({approx}1 MK) and cold (hydrogen and helium) lines. We suggest that the cyclonic appearance and overall evolution of the structure can be interpreted in terms of the expansion of helical structures into the cavity, and the movement of plasma along helical structures which appears as a rotation when viewed along the helix axis. The coordinated movement of material between prominence and cavity suggests that they are structurally linked. Complexity is great due to the combined effect of these actions and the line-of-sight integration through the structure which contains tangled fields.

  11. Chemical evolution with rotating massive star yields - I. The solar neighbourhood and the s-process elements

    Science.gov (United States)

    Prantzos, N.; Abia, C.; Limongi, M.; Chieffi, A.; Cristallo, S.

    2018-05-01

    We present a comprehensive study of the abundance evolution of the elements from H to U in the Milky Way halo and local disc. We use a consistent chemical evolution model, metallicity-dependent isotopic yields from low and intermediate mass stars and yields from massive stars which include, for the first time, the combined effect of metallicity, mass loss, and rotation for a large grid of stellar masses and for all stages of stellar evolution. The yields of massive stars are weighted by a metallicity-dependent function of the rotational velocities, constrained by observations as to obtain a primary-like 14N behaviour at low metallicity and to avoid overproduction of s-elements at intermediate metallicities. We show that the Solar system isotopic composition can be reproduced to better than a factor of 2 for isotopes up to the Fe-peak, and at the 10 per cent level for most pure s-isotopes, both light ones (resulting from the weak s-process in rotating massive stars) and the heavy ones (resulting from the main s-process in low and intermediate mass stars). We conclude that the light element primary process (LEPP), invoked to explain the apparent abundance deficiency of the s-elements with A values of ^{12}C/^{13}C in halo red giants, which is rather due to internal processes in those stars.

  12. Analysis and Compensation of Modulation Angular Rate Error Based on Missile-Borne Rotation Semi-Strapdown Inertial Navigation System

    Directory of Open Access Journals (Sweden)

    Jiayu Zhang

    2018-05-01

    Full Text Available The Semi-Strapdown Inertial Navigation System (SSINS provides a new solution to attitude measurement of a high-speed rotating missile. However, micro-electro-mechanical-systems (MEMS inertial measurement unit (MIMU outputs are corrupted by significant sensor errors. In order to improve the navigation precision, a rotation modulation technology method called Rotation Semi-Strapdown Inertial Navigation System (RSSINS is introduced into SINS. In fact, the stability of the modulation angular rate is difficult to achieve in a high-speed rotation environment. The changing rotary angular rate has an impact on the inertial sensor error self-compensation. In this paper, the influence of modulation angular rate error, including acceleration-deceleration process, and instability of the angular rate on the navigation accuracy of RSSINS is deduced and the error characteristics of the reciprocating rotation scheme are analyzed. A new compensation method is proposed to remove or reduce sensor errors so as to make it possible to maintain high precision autonomous navigation performance by MIMU when there is no external aid. Experiments have been carried out to validate the performance of the method. In addition, the proposed method is applicable for modulation angular rate error compensation under various dynamic conditions.

  13. Effect of Rotation Rate on Microstructure and Properties of Underwater Friction Stir Welded 7A04-T6 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    WANG Wen

    2017-10-01

    Full Text Available Underwater friction stir welding (FSW on 7A04-T6 aluminum alloy plates was carried out, and the effect of rotation rate on microstructure and mechanical properties of joints was investigated. The results show that the minimum hardness of underwater FSW joints is located in the thermo-mechanically affected zone. The hardness of welded joints at the high rotation rate of 950r/min exhibits W-shaped distribution, and the average hardness value in the nugget zone is higher than that of welded joints at the low rotation rate of 475, 600, 750r/min. When the rotation rate increases from 475r/min to 750r/min with a constant welding speed of 235mm/min, the precipitated phases in the nugget zone gradually become coarse, and the ultimate tensile strength coefficient of the joint decreases from 89.71% to 82.33%; when rotation rate increases to 950r/min, the precipitated phases dissolve into aluminum matrix during welding, and age after welding. This produces the fine and homogeneous dispersed phases, which results in an increase of the strength coefficient to 89.04% and a certain enhancement of strain hardening capacity and elongation for the joints. All the tensile fracture surfaces exhibit the mixed characteristics of microporous polymerization and cleavage fracture.

  14. 46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. 108.437 Section 108.437 Shipping COAST GUARD, DEPARTMENT OF... Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.437 Pipe sizes and discharge rates for...

  15. Economic analysis of solar industrial process heat systems: A methodology to determine annual required revenue and internal rate of return

    Science.gov (United States)

    Dickinson, W. C.; Brown, K. C.

    1981-08-01

    An economic evaluation of solar industrial process heat systems, is developed to determine the annual required revenue and the internal rate of return. First, a format is provided to estimate the solar system's installed cost, annual operating and maintenance expenses, and net annual solar energy delivered to the industrial process. The annual required revenue and the price of solar is calculated. The economic attractiveness of the potential solar investment can be determined by comparing the price of solar energy with the price of fossilfuel, both expressed in levelized terms. This requires calcuation of the internal rate of return on the solar investment or, in certain cases, the growth rate of return.

  16. SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

    International Nuclear Information System (INIS)

    Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam; Gömöry, Peter; Wang, Tongjiang; Gan, Weiqun; Li, YouPing

    2014-01-01

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s –1

  17. Solar Magnetized Tornadoes: Rotational Motion in a Tornado-like Prominence

    Science.gov (United States)

    Su, Yang; Gömöry, Peter; Veronig, Astrid; Temmer, Manuela; Wang, Tongjiang; Vanninathan, Kamalam; Gan, Weiqun; Li, YouPing

    2014-04-01

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ~5 km s-1.

  18. SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam [IGAM-Kanzelhöhe Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Gömöry, Peter [Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica (Slovakia); Wang, Tongjiang [Department of Physics, the Catholic University of America, Washington, DC 20064 (United States); Gan, Weiqun; Li, YouPing, E-mail: yang.su@uni-graz.at [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2014-04-10

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s{sup –1}.

  19. Effect of Rotation Rate on Microstructure and Properties of Friction Stir Welded Joints of Al/Cu Clad Plates

    Directory of Open Access Journals (Sweden)

    QIAO Ke

    2017-10-01

    Full Text Available Al/Cu clad plates were joined by friction stir welding (FSW, and the effect of rotation rate on microstructure and mechanical properties of joints was investigated. The results show that the laminar structure of aluminum and copper is generated in the weld. With increase the of rotation rate, the grain sizes of aluminum and copper are increased respectively. The average microhardness of the Al/Cu plates exceeds that of the as-received metal of 33.0 HV, and ultimate tensile strength is 127.21 MPa in the nugget zone when rotation rate is 1180 r/min. The microhardness of copper in the nugget zone is 99.7 HV, reached 82.05% of the microhardness of received metal, and void defect is main reason responsible for the decrease of mechanical properties of joints.

  20. Vibration measurements of the Daniel K. Inouye Solar Telescope mount, Coudé rotator, and enclosure assemblies

    Science.gov (United States)

    McBride, William R.; McBride, Daniel R.

    2016-08-01

    The Daniel K. Inouye Solar Telescope (DKIST) will be the largest solar telescope in the world, with a 4-meter off-axis primary mirror and 16 meter rotating Coudé laboratory within the telescope pier. The off-axis design requires a mount similar to an 8-meter on-axis telescope. Both the telescope mount and the Coudé laboratory utilize a roller bearing technology in place of the more commonly used hydrostatic bearings. The telescope enclosure utilizes a crawler mechanism for the altitude axis. As these mechanisms have not previously been used in a telescope, understanding the vibration characteristics and the potential impact on the telescope image is important. This paper presents the methodology used to perform jitter measurements of the enclosure and the mount bearings and servo system in a high-noise environment utilizing seismic accelerometers and high dynamic-range data acquisition equipment, along with digital signal processing (DSP) techniques. Data acquisition and signal processing were implemented in MATLAB. In the factory acceptance testing of the telescope mount, multiple accelerometers were strategically located to capture the six axes-of-motion of the primary and secondary mirror dummies. The optical sensitivity analysis was used to map these mirror mount displacements and rotations into units of image motion on the focal plane. Similarly, tests were done with the Coudé rotator, treating the entire rotating instrument lab as a rigid body. Testing was performed by recording accelerometer data while the telescope control system performed tracking operations typical of various observing scenarios. The analysis of the accelerometer data utilized noise-averaging fast Fourier transform (FFT) routines, spectrograms, and periodograms. To achieve adequate dynamic range at frequencies as low as 3Hz, the use of special filters and advanced windowing functions were necessary. Numerous identical automated tests were compared to identify and select the data sets

  1. THE ROTATION RATES OF MASSIVE STARS: THE ROLE OF BINARY INTERACTION THROUGH TIDES, MASS TRANSFER, AND MERGERS

    Energy Technology Data Exchange (ETDEWEB)

    De Mink, S. E. [Space Telescope Science Institute, Baltimore, MD (United States); Langer, N.; Izzard, R. G. [Argelander-Institut fuer Astronomie der Universitaet Bonn, D-53121 Bonn (Germany); Sana, H.; De Koter, A. [Astronomical Institute Anton Pannekoek, University of Amsterdam, 1098 XH Amsterdam (Netherlands)

    2013-02-20

    Rotation is thought to be a major factor in the evolution of massive stars-especially at low metallicity-with consequences for their chemical yields, ionizing flux, and final fate. Deriving the birth spin distribution is of high priority given its importance as a constraint on theories of massive star formation and as input for models of stellar populations in the local universe and at high redshift. Recently, it has become clear that the majority of massive stars interact with a binary companion before they die. We investigate how this affects the distribution of rotation rates, through stellar winds, expansion, tides, mass transfer, and mergers. For this purpose, we simulate a massive binary-star population typical for our Galaxy assuming continuous star formation. We find that, because of binary interaction, 20{sup +5} {sub -10}% of all massive main-sequence stars have projected rotational velocities in excess of 200 km s{sup -1}. We evaluate the effect of uncertain input distributions and physical processes and conclude that the main uncertainties are the mass transfer efficiency and the possible effect of magnetic braking, especially if magnetic fields are generated or amplified during mass accretion and stellar mergers. The fraction of rapid rotators we derive is similar to that observed. If indeed mass transfer and mergers are the main cause for rapid rotation in massive stars, little room remains for rapidly rotating stars that are born single. This implies that spin-down during star formation is even more efficient than previously thought. In addition, this raises questions about the interpretation of the surface abundances of rapidly rotating stars as evidence for rotational mixing. Furthermore, our results allow for the possibility that all early-type Be stars result from binary interactions and suggest that evidence for rotation in explosions, such as long gamma-ray bursts, points to a binary origin.

  2. Seasonal variations of solar neutrino rates in lithium detector

    OpenAIRE

    Kopylov, Anatoly; Petukhov, Valery

    2002-01-01

    The presence of two monochromatic lines of approximately equal intensity: $^{7}$Be- and pep-neutrinos in the sensitivity plot of lithium detector makes the pattern of the seasonal variations of the effect from solar neutrinos very characteristic in case if the long-wave vacuum oscillations are realized. This can give the very high accuracy in the measurement of the parameters of neutrino oscillations especially if combined with the results obtained by the detector sensitive mainly to $^{7}$Be...

  3. Solar differential rotation in the period 1964-2016 determined by the Kanzelhohe data set

    Czech Academy of Sciences Publication Activity Database

    Beljan, I.P.; Jurdana-Šepić, R.; Brajša, R.; Sudar, D.; Ruždjak, D.; Hržina, D.; Pötzi, W.; Hanslmeier, A.; Veronig, A.; Skokić, Ivica; Wöhl, H.

    2017-01-01

    Roč. 606, October (2017), A72/1-A72/10 E-ISSN 1432-0746 R&D Projects: GA MŠk(CZ) 7E13003 EU Projects: European Commission(XE) 312495 - SOLARNET Institutional support: RVO:67985815 Keywords : Sun * photosphere * rotation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

  4. Measurements of Drag Coefficients and Rotation Rates of Free-Falling Helixes

    KAUST Repository

    Al-Omari, Abdulrhaman A.

    2016-01-01

    in water, glycerol and a mixture of 30% glycerol in water. That generated rotation due to helical angle in water. However, we observe the rotation disappear in glycerol. The movement of the solid helical shapes is imaged using a high-speed video camera

  5. 70-79 Effects of Crop Rotation and NP Fertilizer Rate on Grain Yield a

    African Journals Online (AJOL)

    Primary nutrient (N, P and K) composition of the ... Crop rotation with fertilizer amendment improved the pH of the soil. Crop rotation and ..... Soil organic carbon contents declined regardless of inputs application for continuously cultivated land (Kapkiyai, 1996). Higher. Organic carbon content next to before planting (1.98 %).

  6. 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.)

  7. Singular formalism and admissible control of spacecraft with rotating flexible solar array

    Directory of Open Access Journals (Sweden)

    Lu Dongning

    2014-02-01

    Full Text Available This paper is concerned with the attitude control of a three-axis-stabilized spacecraft which consists of a central rigid body and a flexible sun-tracking solar array driven by a solar array drive assembly. Based on the linearization of the dynamics of the spacecraft and the modal identities about the flexible and rigid coupling matrices, the spacecraft attitude dynamics is reduced to a formally singular system with periodically varying parameters, which is quite different from a spacecraft with fixed appendages. In the framework of the singular control theory, the regularity and impulse-freeness of the singular system is analyzed and then admissible attitude controllers are designed by Lyapunov’s method. To improve the robustness against system uncertainties, an H∞ optimal control is designed by optimizing the H∞ norm of the system transfer function matrix. Comparative numerical experiments are performed to verify the theoretical results.

  8. Baroclinic Instability in the Solar Tachocline for Continuous Vertical Profiles of Rotation, Effective Gravity, and Toroidal Field

    Energy Technology Data Exchange (ETDEWEB)

    Gilman, Peter A., E-mail: gilman@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green, Boulder, CO 80307-3000 (United States)

    2017-06-20

    We present results from an MHD model for baroclinic instability in the solar tachocline that includes rotation, effective gravity, and toroidal field that vary continuously with height. We solve the perturbation equations using a shooting method. Without toroidal fields but with an effective gravity declining linearly from a maximum at the bottom to much smaller values at the top, we find instability at all latitudes except at the poles, at the equator, and where the vertical rotation gradient vanishes (32.°3) for longitude wavenumbers m from 1 to >10. High latitudes are much more unstable than low latitudes, but both have e -folding times that are much shorter than a sunspot cycle. The higher the m and the steeper the decline in effective gravity, the closer the unstable mode peak to the top boundary, where the energy available to drive instability is greatest. The effect of the toroidal field is always stabilizing, shrinking the latitude ranges of instability as the toroidal field is increased. The larger the toroidal field, the smaller the longitudinal wavenumber of the most unstable disturbance. All latitudes become stable for a toroidal field exceeding about 4 kG. The results imply that baroclinic instability should occur in the tachocline at latitudes where the toroidal field is weak or is changing sign, but not where the field is strong.

  9. Stream function method for computing steady rotational transonic flows with application to solar wind-type problems

    International Nuclear Information System (INIS)

    Kopriva, D.A.

    1982-01-01

    A numerical scheme has been developed to solve the quasilinear form of the transonic stream function equation. The method is applied to compute steady two-dimensional axisymmetric solar wind-type problems. A single, perfect, non-dissipative, homentropic and polytropic gas-dynamics is assumed. The four equations governing mass and momentum conservation are reduced to a single nonlinear second order partial differential equation for the stream function. Bernoulli's equation is used to obtain a nonlinear algebraic relation for the density in terms of stream function derivatives. The vorticity includes the effects of azimuthal rotation and Bernoulli's function and is determined from quantities specified on boundaries. The approach is efficient. The number of equations and independent variables has been reduced and a rapid relaxation technique developed for the transonic full potential equation is used. Second order accurate central differences are used in elliptic regions. In hyperbolic regions a dissipation term motivated by the rotated differencing scheme of Jameson is added for stability. A successive-line-overrelaxation technique also introduced by Jameson is used to solve the equations. The nonlinear equation for the density is a double valued function of the stream function derivatives. The velocities are extrapolated from upwind points to determine the proper branch and Newton's method is used to iteratively compute the density. This allows accurate solutions with few grid points

  10. Solar radiation increases suicide rate after adjusting for other climate factors in South Korea.

    Science.gov (United States)

    Jee, Hee-Jung; Cho, Chul-Hyun; Lee, Yu Jin; Choi, Nari; An, Hyonggin; Lee, Heon-Jeong

    2017-03-01

    Previous studies have indicated that suicide rates have significant seasonal variations. There is seasonal discordance between temperature and solar radiation due to the monsoon season in South Korea. We investigated the seasonality of suicide and assessed its association with climate variables in South Korea. Suicide rates were obtained from the National Statistical Office of South Korea, and climatic data were obtained from the Korea Meteorological Administration for the period of 1992-2010. We conducted analyses using a generalized additive model (GAM). First, we explored the seasonality of suicide and climate variables such as mean temperature, daily temperature range, solar radiation, and relative humidity. Next, we identified confounding climate variables associated with suicide rate. To estimate the adjusted effect of solar radiation on the suicide rate, we investigated the confounding variables using a multivariable GAM. Suicide rate showed seasonality with a pattern similar to that of solar radiation. We found that the suicide rate increased 1.008 times when solar radiation increased by 1 MJ/m 2 after adjusting for other confounding climate factors (P Solar radiation has a significant linear relationship with suicide after adjusting for region, other climate variables, and time trends. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

    Directory of Open Access Journals (Sweden)

    M. Benghanem

    2018-03-01

    Full Text Available This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia. The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed. Keywords: Photovoltaic water pumping system, Solar radiation data, Simulation, Flow rate

  12. 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...

  13. Rotational rates of very small asteroids - 123 Brunhild, 376 Geometria, 437 Rhodia and 1224 Fantasia

    Science.gov (United States)

    Barucci, M. A.; di Martino, M.

    1984-07-01

    This paper presents observations of four small main belt asteroids (D Geometria, an accurate rotational period was determined. For the other two asteroids, 437 Rhodia and 1224 Fantasia, only tentative periods are suggested.

  14. Pump--probe measurements of state-to-state rotational energy transfer rates in N2 (v=1)

    International Nuclear Information System (INIS)

    Sitz, G.O.; Farrow, R.L.

    1990-01-01

    We report direct measurements of the state-to-state rotational energy transfer rates for N 2 (υ=1) at 298 K. Stimulated Raman pumping of Q-branch (υ=1 left-arrow 0) transitions is used to prepare a selected rotational state of N 2 in the υ=1 state. After allowing an appropriate time interval for collisions to occur, 2+2 resonance-enhanced multiphoton ionization is used (through the a 1 Π g left-arrow X 1 Σ + g transition) to detect the relative population of the pumped level and other levels to which rotational energy transfer has occurred. We have performed a series of measurements in which a single even rotational level (J i =0--14) is excited and the time-dependent level populations are recorded at three or more delay times. This data set is then globally fit to determine the best set of state-to-state rate constants. The fitting procedure does not place any constraints (such as an exponential gap law) on the J or energy dependence of the rates. We compare our measurements and best-fit rates with results predicted from phenomenological rate models and from a semiclassical scattering calculation of Koszykowski et al. [J. Phys. Chem. 91, 41 (1987)]. Excellent agreement is obtained with two of the models and with the scattering calculation. We also test the validity of the energy-corrected sudden (ECS) scaling theory for N 2 by using our experimental transfer rates as basis rates (J=L→0), finding that the ECS scaling expressions accurately predict the remaining rates

  15. The effects of time, temperature and rotation of water on the corrosion rate of different types of steels

    International Nuclear Information System (INIS)

    Muhamad Daud; Jamaliah Shariff.

    1984-01-01

    By using hot plate/magnetic stirrer and immersion technique, the steel corroded uniformly and their corrosion rates vary due to type of steel, time of immersion, temperature and rotation of water. Therefore the rate of general corrosion, or sealing, of steel alloys is influenced by a number of factors, those best established being the composition of the metal, time, temperature, velocity, cleanliness or roughness of the metal surface and direct contact with solutions of the other materials. (author)

  16. Helioseismic Solar Cycle Changes and Splitting Coefficients

    Indian Academy of Sciences (India)

    tribpo

    Abstract. Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change signi- ficantly with rising phase of the solar cycle. We also find temporal varia- tions in the rotation rate near the solar ...

  17. Effect of flow rate and disc area increment on the efficiency of rotating biological contactor for treating greywater

    International Nuclear Information System (INIS)

    Pathan, A.A.

    2015-01-01

    The performance of greywater treatment through RBC (Rotating Biological Contactor) is related to many factors including rotational speed of disc, surface area of the media, thickness of biological film; quality and flow rate of influent. The plastic media provides surface for biological slime. The slime is rotated alternatively into the settled wastewater and then into atmosphere to provide aerobic conditions for the microorganisms. In this study the performance of RBC is investigated at different flow rates and disk areas of media by introducing additional discs on the shaft of RBC. Initially efficiency of the RBC was observed on six flow rates at the disc area of 9.78m/sup 2/. Furthermore optimized three flow rates were used to augment the disk area. The efficiency of RBC system was improved significantly at disk area of 11.76m/sup 2/ and flow rate of 20 L/h. Under these conditions the removal of BOD5 (Biochemical Oxygen Demand) COD (Chemical Oxygen Demand) and TSS (Total Suspended Solid) was observed 83, 57 and 90% respectively. (author)

  18. Balancing the daylighting and energy performance of solar screens in residential desert buildings: Examination of screen axial rotation and opening aspect ratio

    KAUST Repository

    Sabry, Hanan

    2014-05-01

    Solar screens are typically used to control solar access into building spaces. They proved their usefulness in improving the daylighting and energy performance of buildings in the hot arid desert environments which are endowed with abundance of clear skies.The daylighting and energy performance of solar screens is affected by many parameters. These include screen perforation, depth, reflectivity and color, aspect ratio of openings, shape, tilt angle and rotation. Changing some of these parameters can improve the daylighting performance drastically. However, this can result in increased energy consumption. A balanced solution must be sought, where acceptable daylighting performance would be achieved at minimum energy consumption.This paper aims at defining solar screen designs that achieve visual comfort and at the same time minimum energy consumption in residential desert settings. The study focused on the effect of changing the solar screen axial rotation and the aspect ratio of its openings under the desert clear-sky. The individual and combined effects of changing these parameters were studied.Results of this study demonstrated that a non-rotated solar screen that has wide horizontal openings (aspect ratio of 18:1) proved to be successful in the north and south orientations. Its performance in the east/west orientations was also superior. In contrast, the screen that was rotated along its vertical axis while having small size openings (aspect ratio of 1:1) proved to be more successful in the east/west orientations. Its performance in the north orientation was also good. These solutions enhanced daylighting performance, while maintaining the energy consumption at a minimum.Moreover, it was observed that combining two screen parameters which proved useful in previous studies on daylighting or thermal performance does not add up to better solutions. The combined solutions that were tested in this study did not prove successful in satisfying daylighting and thermal

  19. Software simulation and experimental characterisation of a rotationally asymmetrical concentrator under direct and diffuse solar radiation

    International Nuclear Information System (INIS)

    Freier, Daria; Muhammad-Sukki, Firdaus; Abu-Bakar, Siti Hawa; Ramirez-Iniguez, Roberto; Abubakar Mas’ud, Abdullahi; Albarracín, Ricardo; Ardila-Rey, Jorge Alfredo; Munir, Abu Bakar; Mohd Yasin, Siti Hajar; Bani, Nurul Aini

    2016-01-01

    Highlights: • The performance of the RADTIRC was analysed under direct and diffuse radiation. • Optical gains of 4.66 under direct and 1.94 under diffuse light were achieved. • The experiments show good agreement with the simulations. • The RADTIRC is an attractive alternative for BICPV systems. - Abstract: Making housing carbon neutral is one of the European Union (EU) targets with the aim to reduce energy consumption and to increase on-site renewable energy generation in the domestic sector. Optical concentrators have a strong potential to minimise the cost of building integrated photovoltaic (BIPV) systems by replacing expensive photovoltaic (PV) material whilst maintaining the same electrical output. In this work, the performance of a recently patented optical concentrator known as the rotationally asymmetrical dielectric totally internally reflective concentrator (RADTIRC) was analysed under direct and diffuse light conditions. The RADTIRC has a geometrical concentration gain of 4.969 and two half acceptance angles of ±40° and ±30° respectively along the two axes. Simulation and experimental work has been carried out to determine the optical concentration gain and the angular response of the concentrator. It was found that the RADTIRC has an optical concentration gain of 4.66 under direct irradiance and 1.94 under diffuse irradiance. The experimental results for the single concentrator showed a reduction in concentration gain of 4.2% when compared with simulation data.

  20. Different parameter and technique affecting the rate of evaporation on active solar still -a review

    Science.gov (United States)

    A, Muthu Manokar; D, Prince Winston; A. E, Kabeel; Sathyamurthy, Ravishankar; T, Arunkumar

    2018-03-01

    Water is one of the essential sources for the endurance of human on the earth. As earth having only a small amount of water resources for consumption purpose people in rural and urban areas are getting affected by consuming dirty water that leads to water-borne diseases. Even though ground water is available in small quantity, it has to be treated properly before its use for internal consumption. Brackish water contains dissolve and undissolved contents, and hence it is not suitable for the household purpose. Nowadays, distillation process is done by using passive and active solar stills. The major problem in using passive solar still is meeting higher demand for fresh water. The fresh water production from passive solar still is critically low to meet the demand. To improve the productivity of conventional solar still, input feed water is preheated by integrating the solar still to different collector panels. In this review article, the different parameters that affect the rate of evaporation in an active solar still and the different methods incorporated has been presented. In addition to active distillation system, forced convection technique can be incorporated to increase the yield of fresh water by decreasing the temperature of cover. Furthermore, it is identified that the yield of fresh water from the active desalination system can be improved by sensible and latent heat energy storage. This review will motivate the researchers to decide appropriate active solar still technology for promoting development.

  1. Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

    Science.gov (United States)

    Benghanem, M.; Daffallah, K. O.; Almohammedi, A.

    2018-03-01

    This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV) water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m) and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia). The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan) in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed.

  2. Perioperative Serum Lipid Status and Statin Use Affect the Revision Surgery Rate After Arthroscopic Rotator Cuff Repair.

    Science.gov (United States)

    Cancienne, Jourdan M; Brockmeier, Stephen F; Rodeo, Scott A; Werner, Brian C

    2017-11-01

    Recent animal studies have demonstrated that hyperlipidemia is associated with poor tendon-bone healing after rotator cuff repair; however, these findings have not been substantiated in human studies. To examine any association between hyperlipidemia and the failure of arthroscopic rotator cuff repair requiring revision surgery and to investigate whether the use of statin lipid-lowering agents had any influence on observed associations. Cohort study; Level of evidence, 3. From a national insurance database, patients who underwent arthroscopic rotator cuff repair with perioperative lipid levels (total cholesterol, low-density lipoprotein [LDL], and triglycerides) recorded were reviewed. For each lipid test, patients were stratified into normal, moderate, and high groups based on published standards. For the total cholesterol and LDL cohorts, a subgroup analysis of patients stratified by statin use was performed. The primary outcome measure was ipsilateral revision rotator cuff surgery, including revision repair or debridement. A logistic regression analysis controlling for patient demographics and comorbidities was utilized for comparison. There were 30,638 patients included in the study. The rate of revision rotator cuff surgery was significantly increased in patients with moderate (odds ratio [OR], 1.20; 95% CI, 1.03-1.40; P = .022) and high total cholesterol levels (OR, 1.36; 95% CI, 1.10-1.55; P = .006) compared with patients with normal total cholesterol levels perioperatively. Within each of these groups, patients without statin use had significantly higher rates of revision surgery, while those with statin prescriptions did not. The absolute risk reduction for statin use ranged from 0.24% to 1.87% when stratified by the total cholesterol level, yielding a number needed to treat from 54 to 408 patients. The rate of revision surgery was significantly increased in patients with moderate (OR, 1.24; 95% CI, 1.10-1.41; P = .001) and high LDL levels (OR, 1.46; 95

  3. Precision Measurement of the Beryllium-7 Solar Neutrino Interaction Rate in Borexino

    Science.gov (United States)

    Saldanha, Richard Nigel

    Solar neutrinos, since their first detection nearly forty years ago, have revealed valuable information regarding the source of energy production in the Sun, and have demonstrated that neutrino oscillations are well described by the Large Mixing Angle (LMA) oscillation parameters with matter interactions due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. This thesis presents a precision measurement of the 7Be solar neutrino interaction rate within Borexino, an underground liquid scintillator detector that is designed to measure solar neutrino interactions through neutrino-electron elastic scattering. The thesis includes a detailed description of the analysis techniques developed and used for this measurement as well as an evaluation of the relevant systematic uncertainties that affect the precision of the result. The rate of neutrino-electron elastic scattering from 0.862 MeV 7Be neutrinos is determined to be 45.4 +/- 1.6 (stat) +/- 1.5 (sys) counts/day/100 ton. Due to extensive detector calibrations and improved analysis methods, the systematic uncertainty in the interaction rate has been reduced by more than a factor of two from the previous evaluation. In the no-oscillation hypothesis, the interaction rate corresponds to a 0.862 MeV 7Be electron neutrino flux of (2.75 +/- 0.13) x 10 9 cm-2 sec-1. Including the predicted neutrino flux from the Standard Solar Model yields an electron neutrino survival probability of Pee 0.51 +/- 0.07 and rules out the no-oscillation hypothesis at 5.1sigma The LMA-MSW neutrino oscillation model predicts a transition in the solar Pee value between low ( 10 MeV) energies which has not yet been experimentally confirmed. This result, in conjunction with the Standard Solar Model, represents the most precise measurement of the electron neutrino survival probability for solar neutrinos at sub-MeV energies.

  4. [Effects of reduced solar radiation on winter wheat flag leaf net photosynthetic rate].

    Science.gov (United States)

    Zheng, You-Fei; Ni, Yan-Li; Mai, Bo-Ru; Wu, Rong-Jun; Feng, Yan; Sun, Jian; Li, Jian; Xu, Jing-Xin

    2011-06-01

    Taking winter wheat Triticum aestivum L. (cv. Yangmai 13) as test material, a field experiment was conducted in Nanjing City to study the effects of simulated reduced solar radiation on the diurnal variation of winter wheat flag leaf photosynthetic rate and the main affecting factors. Five treatments were installed, i. e., 15% (T15), 20% (T20) , 40% (T40), 60% (T60), and 100% (CK) of total incident solar radiation. Reduced solar irradiance increased the chlorophyll and lutein contents significantly, but decreased the net photosynthetic rate (Pn). Under different solar irradiance, the diurnal variation of Pn had greater difference, and the daily maximum Pn was in the order of CK > T60 > T40 > T 20 > T15. In CK, the Pn exhibited a double peak diurnal curve; while in the other four treatments, the Pn showed a single peak curve, and the peak was lagged behind that of CK. Correlation analysis showed that reduced solar irradiance was the main factor affecting the diurnal variation of Pn, but the physiological parameters also played important roles in determining the diurnal variation of Pn. In treatments T60 and T40, the photosynthesis active radiation (PAR), leaf temperature (T1) , stomatal conductance (Gs) , and transpiration rate (Tr) were significantly positively correlated with Pn, suggesting their positive effects on Pn. The intercellular CO2 concentration (Ci) and stomatal limitation (Ls) had significant negative correlations with Pn in treatments T60 and T40 but significant positive correlations with Pn in treatments T20 and T15, implying that the Ci and Ls had negative (or positive) effects on Pn when the solar irradiance was higher (or lower) than 40% of incident solar irradiance.

  5. Design of cycler trajectories and analysis of solar influences on radioactive decay rates during space missions

    Science.gov (United States)

    Rogers, Blake A.

    investigated to determine if they can be used to find new cycler trajectories, as well as those previously discovered. First order approximations to the relative motion equations are unfruitful for Earth-Mars cyclers because the variation in radial distance from the Sun is too large. However, using optimization techniques, cycling trajectories are found for the Earth-Mars, Earth-Ceres, and Mars-Ceres systems. Experiments showing a seasonal variation of the nuclear decay rates of a number of different nuclei and decay anomalies--- apparently related to solar flares and solar rotation--- have suggested that the Sun may somehow be influencing nuclear decay processes. Recently, there have been searches for such an effect in 238Pu nuclei contained in the radioisotope thermoelectric generators on board the Cassini spacecraft. In this work, that analysis is modified and extended to obtain constraints on anomalous decays of 238Pu over a wider range of models, but these limits cannot be applied to other nuclei if the anomaly is composition-dependent. It is also shown that it may require very high sensitivity for terrestrial experiments to discriminate among some models if such a decay anomaly exists, motivating the consideration of future spacecraft experiments which would require less precision. A mission on which such an experiment could be run is proposed. The proposed mission will take various isotopes on a spacecraft that has a large variation in radial distance and return them to Earth. Two different types of trajectories are considered: one with intermediate Venus flybys and one that injects directly into an Earth-resonant orbit. It is shown that each of these types of trajectories have their relative merits with regards to the scientific objective. The suitability of the upcoming Solar Probe Plus and Solar Orbiter missions to perform this experiment is also investigated.

  6. Rotaphone, a mechanical seismic sensor system for field rotation rate measurements and its in situ calibration

    Czech Academy of Sciences Publication Activity Database

    Brokešová, J.; Málek, Jiří; Kolínský, Petr

    2012-01-01

    Roč. 16, č. 4 (2012), s. 603-621 ISSN 1383-4649 R&D Projects: GA ČR GAP210/10/0925 Grant - others:GA MŠk(CZ) LM2010008 Program:LM Institutional support: RVO:67985891 Keywords : rotational seismology * sensor * six-degree-of-freedom Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.388, year: 2012

  7. Measurements of Drag Coefficients and Rotation Rates of Free-Falling Helixes

    KAUST Repository

    Al-Omari, Abdulrhaman A.

    2016-05-01

    The motion of bacteria in the environment is relevant to several fields. At very small scales and with simple helical shapes, we are able to describe experimentally and mathematically the motion of solid spirals falling freely within a liquid pool. Using these shapes we intend to mimic the motion of bacteria called Spirochetes. We seek to experimentally investigate the linear and the rotational motion of such shapes. A better understanding of the dynamics of this process will be practical not only on engineering and physics, but the bioscience and environmental as well. In the following pages, we explore the role of the shape on the motion of passive solid helixes in different liquids. We fabricate three solid helical shapes and drop them under gravity in water, glycerol and a mixture of 30% glycerol in water. That generated rotation due to helical angle in water. However, we observe the rotation disappear in glycerol. The movement of the solid helical shapes is imaged using a high-speed video camera. Then, the images are analyzed using the supplied software and a computer. Using these simultaneous measurements, we examine the terminal velocity of solid helical shapes. Using this information we computed the drag coefficient and the drag force. We obtain the helical angular velocity and the torque applied to the solid. The results of this study will allow us to more accurately predict the motion of solid helical shape. This analysis will also shed light onto biological questions of bacteria movement.

  8. SOLAR PHOTOIONIZATION RATES FOR INTERSTELLAR NEUTRALS IN THE INNER HELIOSPHERE: H, He, O, AND Ne

    Energy Technology Data Exchange (ETDEWEB)

    Bochsler, P.; Kucharek, H.; Möbius, E. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Bzowski, Maciej; Sokół, Justyna M. [Space Research Center of the Polish Academy of Sciences, Ul. Bartycka 18A, 00-716 Warsaw (Poland); Didkovsky, Leonid; Wieman, Seth, E-mail: bochsler@space.unibe.ch [Space Sciences Center, University of Southern California, Los Angeles, CA 90089-1341 (United States)

    2014-01-01

    Extreme UV (EUV) spectra from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Solar EUV Experiment are used to infer photoionization rates in the inner heliosphere. Relating these rates to various proxies describing the solar EUV radiation, we construct a multi-linear model which allows us to extrapolate ionization rates back to periods when no routine measurements of the solar EUV spectral distribution have been available. Such information is important, e.g., for comparing conditions of the interstellar neutral particles in the inner heliosphere at the time of Ulysses/GAS observations with conditions during the more recent observations of the Interstellar Boundary Explorer. From a period of 11 yr when detailed spectra from both TIMED and three proxies—Solar and Heliospheric Observatory/CELIAS/SEM-rates, F10.7 radio flux, and Mg II core-to-wing indices—have been available, we conclude that the simple model is able to reproduce the photoionization rates with an uncertainty of typically 5%.

  9. 78 FR 34371 - Centinela Solar Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2013-06-07

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1561-000] Centinela Solar Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Centinela Solar Energy, LLC's application for market-based rate authority, with an accompanying rate...

  10. 77 FR 24697 - Cooper Mountain Solar 2, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2012-04-25

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-1566-000] Cooper Mountain Solar 2, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Cooper Mountain Solar 2, LLC's application for market-based rate authority, with an accompanying rate...

  11. 76 FR 44322 - Copper Mountain Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2011-07-25

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-4055-000] Copper Mountain Solar 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Copper Mountain Solar 1, LLC's application for market-based rate authority, with an accompanying rate...

  12. One common structural peculiarity of the Solar system bodies including the star, planets, satellites and resulting from their globes rotation

    Science.gov (United States)

    Kochemasov, G. G.

    2008-09-01

    be less dense diminishing its angular momentum. A crosscutting wave rippling producing chains of square craters here is also clearly visible. Sun presents a special case because its equatorial region rotates faster than the higher latitudes. It could be attributed to an important loss of angular momentum by this region during formation of planets (significant transfer of momentum to the planetary system) and its compensation according to the Le Chatelier rule by the faster rotation. But, in turn, this faster rotation causes an intensive destruction of this region in tendency to keep " status quo". The photosphere is "perforated" by darker colder spots deep up to 300 (maybe more?) km - famous solar spots long to 200000 km and smaller pores (Fig. 7). In the chromosphere there is a remarkable loss of "heavy" Ca ion from this region (compare with the loss of methane from the equatorial region of Saturn). Under more close inspection of other planetary bodies this uniform separation of tropical and extra-tropical zones should be discovered.

  13. Rapid vibrational and rotational energy-transfer rates in heated carbon dioxide collisions by double-resonance laser spectroscopy

    International Nuclear Information System (INIS)

    Thomason, M.D.

    1982-07-01

    Rates for resonant vibrational and rotational energy transfer from the 001 state by CO 2 + CO 2 collisions have been measured. All data were obtained by double resonance spectroscopy with CO 2 lasers in a 2.5 meter absorption cell at 700 0 K. Results for rotation transfer include pumped-level relaxation and the response of other 001 levels with ΔJ up to 18. These data are compared to four relevant collision models via a 35-level rate equation analysis. Sequence-band (002 → 101) and hot-band (011 → 110) lasting have been used to observe resonant nu 3 -transfer relaxation involving 001 + 001 reversible 002 + 000, 001 + 100 reversible 101 + 000, and 001 + 010 reversible 011 + 000. A multilevel rate analysis has been utilized to determine the rate coefficients for 001 going to the 002, the 101, and the 011 levels. Part of the hot-band data has been interpreted as due to 110 + 000 reversible 100 + 010, and the associated rate constant has been estimated. The results of the study are compared to the theory and to other experiments

  14. The role of plasma induced substrate heating during high rate deposition of microcrystalline solar cells

    NARCIS (Netherlands)

    van den Donker, M.N.; Schmitz, R.; Appenzeller, W.; Rech, B.; Kessels, W.M.M.; Sanden, van de M.C.M.

    2006-01-01

    A 13.56 MHz parallel plate hydrogen-dild. silane plasma, operated at high pressure and high power, was used to deposit microcryst. silicon solar cells with efficiencies of 6-9% at high deposition rates of 0.4-1.2 nm/s. In this regime new challenges arise regarding temp. control, since the high

  15. Measurement of the solar neutrino capture rate with gallium metal, part III

    International Nuclear Information System (INIS)

    Elliott, Steven Ray

    2008-01-01

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keY of 65.4 +3.1 3.0 (stat) +2.6 -2.8 (syst) SNU. The weighted average of the results of all three Ga solar neUlrino experiments, SAGE, Gallex, and GNO, is now 66.1 ± 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37 Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior 51 Cr neutrino-source experiments with Ga, is 0.88 ± 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71 Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63--67 SNU with an uncertainly of about 5%, in good agreement with experiment. We derive the current value of the pp neutrino flux produced in the Sun to be φ · pp = (6.1 ± 0.8) x 10 10 /(cm 2 s), which agrees well with the flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  16. Ring current energy injection rate and solar wind-magnetosphere energy coupling

    International Nuclear Information System (INIS)

    Lee, L.C.; Kan, J.R.; Akasofu, S.-I.

    1982-01-01

    The purpose of this paper is to (i) formulate the ring current injection rate Usub(R) in terms of phisub(CT) (cross-tail potential drop) by assuming that the ring current formation is a direct consequence of an enhanced convection, (ii) examine the relationship between the injection rate Usub(R) and the power transferred from the solar wind to the magnetosphere and (iii) demonstrate that an enhanced convection indeed leads to the formation of the ring current. (author)

  17. The impact of water vapor transmission rate on the lifetime of flexible polymer solar cells

    Science.gov (United States)

    Hauch, Jens A.; Schilinsky, Pavel; Choulis, Stelios A.; Rajoelson, Sambatra; Brabec, Christoph J.

    2008-09-01

    In this paper we perform accelerated lifetime testing on high efficiency flexible poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM) solar cells encapsulated with food package quality barrier films with a water vapor transmission rate of 0.2 g/(m2 day) at 65 °C/85% relative humidity. We show that lifetimes exceeding 1250 h, even at high temperature/high humidity conditions, may be reached, proving that organic solar cells are significantly less sensitive against the environmental effects of water and oxygen than previously expected.

  18. Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence

    International Nuclear Information System (INIS)

    Hadid, L. Z.; Sahraoui, F.; Galtier, S.

    2017-01-01

    Estimation of the energy cascade rate in the inertial range of solar wind turbulence has been done so far mostly within incompressible magnetohydrodynamics (MHD) theory. Here, we go beyond that approximation to include plasma compressibility using a reduced form of a recently derived exact law for compressible, isothermal MHD turbulence. Using in situ data from the THEMIS / ARTEMIS spacecraft in the fast and slow solar wind, we investigate in detail the role of the compressible fluctuations in modifying the energy cascade rate with respect to the prediction of the incompressible MHD model. In particular, we found that the energy cascade rate (1) is amplified particularly in the slow solar wind; (2) exhibits weaker fluctuations in spatial scales, which leads to a broader inertial range than the previous reported ones; (3) has a power-law scaling with the turbulent Mach number; (4) has a lower level of spatial anisotropy. Other features of solar wind turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models.

  19. Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Hadid, L. Z.; Sahraoui, F.; Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr [LPP, CNRS, Ecole Polytechnique, UPMC Univ Paris 06, Univ. Paris-Sud, Observatoire de Paris, Université Paris-Saclay, Sorbonne Universités, PSL Research University, F-91128 Palaiseau (France)

    2017-03-20

    Estimation of the energy cascade rate in the inertial range of solar wind turbulence has been done so far mostly within incompressible magnetohydrodynamics (MHD) theory. Here, we go beyond that approximation to include plasma compressibility using a reduced form of a recently derived exact law for compressible, isothermal MHD turbulence. Using in situ data from the THEMIS / ARTEMIS spacecraft in the fast and slow solar wind, we investigate in detail the role of the compressible fluctuations in modifying the energy cascade rate with respect to the prediction of the incompressible MHD model. In particular, we found that the energy cascade rate (1) is amplified particularly in the slow solar wind; (2) exhibits weaker fluctuations in spatial scales, which leads to a broader inertial range than the previous reported ones; (3) has a power-law scaling with the turbulent Mach number; (4) has a lower level of spatial anisotropy. Other features of solar wind turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models.

  20. Determination of the axial rotation rate using apsidal motion for early-type eclipsing binaries

    Science.gov (United States)

    Khaliullin, Kh. F.; Khaliullina, A. I.

    2007-11-01

    Because the modern theory of stellar structure and evolution has a sound observational basis, we can consider that the apsidal parameters k2 computed in terms of this theory correctly reflect the radial density distribution in stars of different masses and spectral types. This allows us to address the problem of apsidal motion in close binary systems in a new way. Unlike the traditional approach, in this paper we use the observed apsidal periods Uobs to estimate the angular axial velocities of components, ωr, at fixed model values of k2. We use this approach to analyse the observational data for 28 eclipsing systems with known Uobs and early-type primaries (M >= 1.6 Msolar or Te >= 6000 K). We measure the age of the system in units of the synchronization time, t/tsyn. Our analysis yielded the following results. (i) There is a clear correlation between ωr/ωsyn and t/tsyn: the younger a star, the higher the angular velocity of its axial rotation in units of ωsyn, the angular velocity at pseudo-synchronization. This correlation is more significant and obvious if the synchronization time, tsyn, is computed in terms of the Zahn theory. (ii) This observational fact implies that the synchronization of early-type components in close binary systems continues on the main sequence. The synchronization times for the inner layers of the components (i.e. those that are responsible for apsidal motion) are about 1.6 and 3.1 dex longer than those predicted by the theories of Zahn and Tassoul, respectively. The average initial angular velocities (for the zero-age main sequence) are equal to ω0/ωsyn ~ 2.0. The dependence of the parameter E2 on stellar mass probably needs to be refined in the Zahn theory. (iii) Some components of the eclipsing systems of the sample studied show radially differential axial rotation. This is consistent with the Zahn theory, which predicts that the synchronization starts at the surface, where radiative damping of dynamical tides occurs, and

  1. The Effect of the Volume Flow rate on the Efficiency of a Solar Collector

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    rates. Theoretically, a simplified model of the solar collector panel is built by means of the CFD (Computational Fluid Dynamics) code Fluent, where the geometry of the collector panel except the casing is fully modeled. Both lateral and longitudinal heat conduction in the absorber fins, the heat...... transfer from the absorber to the solar collector fluid and the heat loss from the absorber are considered. Flow and temperature distribution in the collector panel are investigated with buoyancy effect. Measurements are carried out with the solar collector panel. Collector efficiencies are measured......The flow distribution inside a collector panel with an area of 12.5 m² and with 16 parallel connected horizontal fins and the effect of the flow nonuniformity on the risk of boiling and on the collector efficiency have been theoretically and experimentally investigated for different volume flow...

  2. Precision Measurement of the Be7 Solar Neutrino Interaction Rate in Borexino

    Science.gov (United States)

    Bellini, G.; Benziger, J.; Bick, D.; Bonetti, S.; Bonfini, G.; Buizza Avanzini, M.; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Carraro, C.; Cavalcante, P.; Chavarria, A.; D'Angelo, D.; Davini, S.; Derbin, A.; Etenko, A.; Fomenko, K.; Franco, D.; Galbiati, C.; Gazzana, S.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Grandi, L.; Guardincerri, E.; Hardy, S.; Ianni, Aldo; Ianni, Andrea; Kobychev, V.; Korablev, D.; Korga, G.; Koshio, Y.; Kryn, D.; Laubenstein, M.; Lewke, T.; Litvinovich, E.; Loer, B.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Machulin, I.; Manecki, S.; Maneschg, W.; Manuzio, G.; Meindl, Q.; Meroni, E.; Miramonti, L.; Misiaszek, M.; Montanari, D.; Mosteiro, P.; Muratova, V.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Peña-Garay, C.; Perasso, L.; Perasso, S.; Pocar, A.; Raghavan, R. S.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Sabelnikov, A.; Saldanha, R.; Salvo, C.; Schönert, S.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Vignaud, D.; Vogelaar, R. B.; von Feilitzsch, F.; Winter, J.; Wojcik, M.; Wright, A.; Wurm, M.; Xu, J.; Zaimidoroga, O.; Zavatarelli, S.; Zuzel, G.

    2011-09-01

    The rate of neutrino-electron elastic scattering interactions from 862 keV Be7 solar neutrinos in Borexino is determined to be 46.0±1.5(stat)-1.6+1.5(syst)counts/(day·100ton). This corresponds to a νe-equivalent Be7 solar neutrino flux of (3.10±0.15)×109cm-2s-1 and, under the assumption of νe transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0σ. A global solar neutrino analysis with free fluxes determines Φpp=6.06-0.06+0.02×1010cm-2s-1 and ΦCNOMikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.

  3. Void fraction and velocity measurement of simulated bubble in a rotating disc using high frame rate neutron radiography.

    Science.gov (United States)

    Saito, Y; Mishima, K; Matsubayashi, M

    2004-10-01

    To evaluate measurement error of local void fraction and velocity field in a gas-molten metal two-phase flow by high-frame-rate neutron radiography, experiments using a rotating stainless-steel disc, which has several holes of various diameters and depths simulating gas bubbles, were performed. Measured instantaneous void fraction and velocity field of the simulated bubbles were compared with the calculated values based on the rotating speed, the diameter and the depth of the holes as parameters and the measurement error was evaluated. The rotating speed was varied from 0 to 350 rpm (tangential velocity of the simulated bubbles from 0 to 1.5 m/s). The effect of shutter speed of the imaging system on the measurement error was also investigated. It was revealed from the Lagrangian time-averaged void fraction profile that the measurement error of the instantaneous void fraction depends mainly on the light-decay characteristics of the fluorescent converter. The measurement error of the instantaneous local void fraction of simulated bubbles is estimated to be 20%. In the present imaging system, the light-decay characteristics of the fluorescent converter affect the measurement remarkably, and so should be taken into account in estimating the measurement error of the local void fraction profile.

  4. Void fraction and velocity measurement of simulated bubble in a rotating disc using high frame rate neutron radiography

    International Nuclear Information System (INIS)

    Saito, Y.; Mishima, K.; Matsubayashi, M.

    2004-01-01

    To evaluate measurement error of local void fraction and velocity field in a gas-molten metal two-phase flow by high-frame-rate neutron radiography, experiments using a rotating stainless-steel disc, which has several holes of various diameters and depths simulating gas bubbles, were performed. Measured instantaneous void fraction and velocity field of the simulated bubbles were compared with the calculated values based on the rotating speed, the diameter and the depth of the holes as parameters and the measurement error was evaluated. The rotating speed was varied from 0 to 350 rpm (tangential velocity of the simulated bubbles from 0 to 1.5 m/s). The effect of shutter speed of the imaging system on the measurement error was also investigated. It was revealed from the Lagrangian time-averaged void fraction profile that the measurement error of the instantaneous void fraction depends mainly on the light-decay characteristics of the fluorescent converter. The measurement error of the instantaneous local void fraction of simulated bubbles is estimated to be 20%. In the present imaging system, the light-decay characteristics of the fluorescent converter affect the measurement remarkably, and so should be taken into account in estimating the measurement error of the local void fraction profile

  5. 76 FR 32188 - Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2011-06-03

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-3635-000] Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... Hatch Solar Energy Center 1, LLC's application for market-based rate authority, with an accompanying...

  6. 78 FR 28836 - Arlington Valley Solar Energy II, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2013-05-16

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1430-000] Arlington Valley Solar Energy II, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request..., of Arlington Valley Solar Energy II, LLC's application for market-based rate authority, with an...

  7. Impact of Rate Design Alternatives on Residential Solar Customer Bills. Increased Fixed Charges, Minimum Bills and Demand-based Rates

    Energy Technology Data Exchange (ETDEWEB)

    Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States); Davidson, Carolyn [National Renewable Energy Lab. (NREL), Golden, CO (United States); McLaren, Joyce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, John [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    With rapid growth in energy efficiency and distributed generation, electric utilities are anticipating stagnant or decreasing electricity sales, particularly in the residential sector. Utilities are increasingly considering alternative rates structures that are designed to recover fixed costs from residential solar photovoltaic (PV) customers with low net electricity consumption. Proposed structures have included fixed charge increases, minimum bills, and increasingly, demand rates - for net metered customers and all customers. This study examines the electricity bill implications of various residential rate alternatives for multiple locations within the United States. For the locations analyzed, the results suggest that residential PV customers offset, on average, between 60% and 99% of their annual load. However, roughly 65% of a typical customer's electricity demand is non-coincidental with PV generation, so the typical PV customer is generally highly reliant on the grid for pooling services.

  8. Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

    Science.gov (United States)

    Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

    2011-10-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

  9. 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.

  10. Theoretical study of electronic transfer current rate at dye-sensitized solar cells

    Science.gov (United States)

    AL-Agealy, Hadi J. M.; AlMaadhede, Taif Saad; Hassooni, Mohsin A.; Sadoon, Abbas K.; Ashweik, Ahmed M.; Mahdi, Hind Abdlmajeed; Ghadhban, Rawnaq Qays

    2018-05-01

    In this research, we present a theoretical study of electronic transfer kinetics rate in N719/TiO2 and N719/ZnO dye-sensitized solar cells (DSSC) systems using a simple model depending on the postulate of quantum mechanics theory. The evaluation of the electronic transition current rate in DSSC systems are function of many parameters such that; the reorientation transition energies ΛSe m D y e , the transition coupling parameter ℂT(0), potential exponential effect e-(E/C-EF ) kBT , unit cell volume VSem, and temperature T. Furthermore, the analysis of electronic transfer current rate in N719/TiO2 and N719/ZnO systems show that the rate upon dye-sensitization solar cell increases with increases of transition coupling parameter, decreasing potential that building at interface a results of different material in this devices and increasing with reorientation transition energy. On the other hand, we can find the electronic transfer behavior is dependent of the dye absorption spectrum and mainly depending on the reorientation of transition energy. The replacement of the solvents in both DSSC system caused increasing of current rates dramatically depending on polarity of solvent in subset devices. This change in current rate of electron transfer were attributed to much more available of recombination sites introduced by the solvents medium. The electronic transfer current dynamics are shown to occurs in N719/TiO2 system faster many time compare to ocuures at N719/ZnO system, this indicate that TiO2 a is a good and active material compare with ZnO to using in dye sensitized solar cell devices. In contrast, the large current rate in N719/TiO2 comparing to ZnO of N719/ZnO systems indicate that using TiO2 with N719 dye lead to increasing the efficiency of DSSC.

  11. Investigating stellar surface rotation using observations of starspots

    DEFF Research Database (Denmark)

    Korhonen, Heidi Helena

    2011-01-01

    Rapid rotation enhances the dynamo operating in stars, and thus also introduces significantly stronger magnetic activity than is seen in slower rotators. Many young cool stars still have the rapid, primordial rotation rates induced by the interstellar molecular cloud from which they were formed....... Also older stars in close binary systems are often rapid rotators. These types of stars can show strong magnetic activity and large starspots. In the case of large starspots which cause observable changes in the brightness of the star, and even in the shapes of the spectral line profiles, one can get...... information on the rotation of the star. At times even information on the spot rotation at different stellar latitudes can be obtained, similarly to the solar surface differential rotation measurements using magnetic features as tracers. Here, I will review investigations of stellar rotation based...

  12. Plate rotations, fault slip rates, fault locking, and distributed deformation in northern Central America from 1999-2017 GPS observations

    Science.gov (United States)

    Ellis, A. P.; DeMets, C.; Briole, P.; Cosenza, B.; Flores, O.; Guzman-Speziale, M.; Hernandez, D.; Kostoglodov, V.; La Femina, P. C.; Lord, N. E.; Lasserre, C.; Lyon-Caen, H.; McCaffrey, R.; Molina, E.; Rodriguez, M.; Staller, A.; Rogers, R.

    2017-12-01

    We describe plate rotations, fault slip rates, and fault locking estimated from a new 100-station GPS velocity field at the western end of the Caribbean plate, where the Motagua-Polochic fault zone, Middle America trench, and Central America volcanic arc faults converge. In northern Central America, fifty-one upper-plate earthquakes caused approximately 40,000 fatalities since 1900. The proximity of main population centers to these destructive earthquakes and the resulting loss of human life provide strong motivation for studying the present-day tectonics of Central America. Plate rotations, fault slip rates, and deformation are quantified via a two-stage inversion of daily GPS position time series using TDEFNODE modeling software. In the first stage, transient deformation associated with three M>7 earthquakes in 2009 and 2012 is estimated and removed from the GPS position time series. In Stage 2, linear velocities determined from the corrected GPS time series are inverted to estimate deformation within the western Caribbean plate, slip rates along the Motagua-Polochic faults and faults in the Central America volcanic arc, and the gradient of extension in the Honduras-Guatemala wedge. Major outcomes of the second inversion include the following: (1) Confirmation that slip rates on the Motagua fault decrease from 17-18 mm/yr at its eastern end to 0-5 mm/yr at its western end, in accord with previous results. (2) A transition from moderate subduction zone locking offshore from southern Mexico and parts of southern Guatemala to weak or zero coupling offshore from El Salvador and parts of Nicaragua along the Middle America trench. (3) Evidence for significant east-west extension in southern Guatemala between the Motagua fault and volcanic arc. Our study also shows evidence for creep on the eastern Motagua fault that diminishes westward along the North America-Caribbean plate boundary.

  13. Effect of brining on the drying rate of tilapia in a solar tunnel dryer

    Energy Technology Data Exchange (ETDEWEB)

    Kituu, G.M.; Shitanda, D.; Kanali, C.L.; Mailutha, J.T. [Jomo Kenyatta Univ. of Agriculture and Technology, Nairobi (Kenya). BEED

    2008-07-01

    In addition to being a source of protein, fish is an important source of local and foreign currency earnings in Kenya. A substantial amount of fish production is exported. Approximately 30 per cent is exported to the European Union, the United States, and countries in the Middle East, but nearly half of the total annual fish harvest in Kenya goes to waste due to poor processing and preservation. Measures must be taken to ensure the fish industry is protected and waste is minimized, since the livelihood of over 500,000 people depends on fish as a source of proteins and employment. Therefore, it is necessary to implement appropriate and affordable processing and preservation techniques for fish at the artisanal landing sites in order to reduce the wastage and spoilage of fish during oversupply, and to enhance long storage. This paper presented studies that were conducted to determine the effect of brining on the drying rate of tilapia in a solar tunnel dryer. The paper discussed the materials and methods, including a description of the solar tunnel dryer system; the brining process of fish; the fish drying process; and data analysis. It was concluded that limiting the amount of salt used in brining, and subsequently dehydrating fish with a solar tunnel dryer achieves a more stable and suitable dried fish product than osmotic dehydration or solar drying process separately. 19 refs., 5 figs., 2 appendices.

  14. Rotational studies of late-type stars. II. Ages of solar-type stars and the rotational history of the sun

    International Nuclear Information System (INIS)

    Soderblom, D.R.

    1983-01-01

    In the first part of this investigation, age indicators for solar-type stars are discussed. A Li abundance-age calibration is derived; it indicates that 1 M/sub sun/ stars have lost as much as 80% of their initial Li before reaching the main sequence. The e-folding time for Li depletion on the main sequence is 1 1/4 Gyr. The distribution of Li abundances for 1 M/sub sun/ stars is consistent with a uniform initial Li abundance for all stars

  15. Non-photic solar associations of heart rate variability and myocardial infarction

    Science.gov (United States)

    Cornélissen, Germaine; Halberg, Franz; Breus, Tamara; Syutkina, Elena V.; Baevsky, Roman; Weydahl, Andi; Watanabe, Yoshihiko; Otsuka, Kuniaki; Siegelova, Jarmila; Fiser, Bohumil; Bakken, Earl E.

    2002-03-01

    Alignment of serial epidemiological, physiological, including electrocardiographic data with variations in galactic cosmic rays, geomagnetic activity, and atmospheric pressure suggests the possibility of links among these physical environmental variations and health risks, such as myocardial infarctions and ischemic strokes, among others. An increase in the incidence of myocardial infarction in association with magnetic storms, reported by several investigators from Russia, Israel, Italy and Mexico, accounts in Minnesota for a 5% (220cases/year) increase in mortality during years of maximal solar activity by comparison with years of minimal solar activity. Magnetic storms are also found to decrease heart rate variability (HRV), indicating a possible mechanism since a reduced HRV is a prognostic factor for coronary artery disease and myocardial infarction. Longitudinal electrocardiographic monitoring for a week or much longer spans in different geographic locations, notably in the auroral oval, further suggests that the decrease in HRV affects spectral regions other than that around 3.6s (0.15-0.40Hz), reportedly associated with the parasympathetic nervous system. Differences in some associations are observed from solar cycle to solar cycle, and as a function of solar cycle stage, a finding resolving controversies. Coordinated physiological and physical monitoring, the scope of an international project on the Biosphere and the Cosmos, seeks reference values for a better understanding of environmental effects on human health and for testing the merit of space weather reports that could prompt countermeasures in space and on earth. Physiological data being collected systematically worldwide and morbidity/mortality statistics from causes such as myocardial infarction and stroke constitute invaluable data bases for assessing changes within the physiological range, for detecting environmental effects and for recognizing endogenous as well as exogenous disease

  16. Modeling Long Term Corn Yield Response to Nitrogen Rate and Crop Rotation

    Directory of Open Access Journals (Sweden)

    Laila Alejandra Puntel

    2016-11-01

    Full Text Available Improved prediction of optimal N fertilizer rates for corn (Zea mays L. can reduce N losses and increase profits. We tested the ability of the Agricultural Production Systems sIMulator (APSIM to simulate corn and soybean (Glycine max L. yields, the economic optimum N rate (EONR using a 16-year field-experiment dataset from central Iowa, USA that included two crop sequences (continuous corn and soybean-corn and five N fertilizer rates (0, 67, 134, 201, and 268 kg N ha-1 applied to corn. Our objectives were to: a quantify model prediction accuracy before and after calibration, and report calibration steps; b compare crop model-based techniques in estimating optimal N rate for corn; and c utilize the calibrated model to explain factors causing year to year variability in yield and optimal N. Results indicated that the model simultaneously simulated well long-term crop yields response to N (relative root mean square error, RRMSE of 19.6% before and 12.3% after calibration, which provided strong evidence that important soil and crop processes were accounted for in the model. The prediction of EONR was more complex and had greater uncertainty than the prediction of crop yield (RRMSE of 44.5% before and 36.6% after calibration. For long-term site mean EONR predictions, both calibrated and uncalibrated versions can be used as the 16-yr mean differences in EONR’s were within the historical N rate error range (40 to 50 kg N ha-1. However, for accurate year-by-year simulation of EONR the calibrated version should be used. Model analysis revealed that higher EONR values in years with above normal spring precipitation were caused by an exponential increase in N loss (denitrification and leaching with precipitation. We concluded that long term experimental data were valuable in testing and refining APSIM predictions. The model can be used as a tool to assist N management guidelines in the US Midwest and we identified five avenues on how the model can add

  17. Modeling Long-Term Corn Yield Response to Nitrogen Rate and Crop Rotation.

    Science.gov (United States)

    Puntel, Laila A; Sawyer, John E; Barker, Daniel W; Dietzel, Ranae; Poffenbarger, Hanna; Castellano, Michael J; Moore, Kenneth J; Thorburn, Peter; Archontoulis, Sotirios V

    2016-01-01

    Improved prediction of optimal N fertilizer rates for corn ( Zea mays L. ) can reduce N losses and increase profits. We tested the ability of the Agricultural Production Systems sIMulator (APSIM) to simulate corn and soybean ( Glycine max L. ) yields, the economic optimum N rate (EONR) using a 16-year field-experiment dataset from central Iowa, USA that included two crop sequences (continuous corn and soybean-corn) and five N fertilizer rates (0, 67, 134, 201, and 268 kg N ha -1 ) applied to corn. Our objectives were to: (a) quantify model prediction accuracy before and after calibration, and report calibration steps; (b) compare crop model-based techniques in estimating optimal N rate for corn; and (c) utilize the calibrated model to explain factors causing year to year variability in yield and optimal N. Results indicated that the model simulated well long-term crop yields response to N (relative root mean square error, RRMSE of 19.6% before and 12.3% after calibration), which provided strong evidence that important soil and crop processes were accounted for in the model. The prediction of EONR was more complex and had greater uncertainty than the prediction of crop yield (RRMSE of 44.5% before and 36.6% after calibration). For long-term site mean EONR predictions, both calibrated and uncalibrated versions can be used as the 16-year mean differences in EONR's were within the historical N rate error range (40-50 kg N ha -1 ). However, for accurate year-by-year simulation of EONR the calibrated version should be used. Model analysis revealed that higher EONR values in years with above normal spring precipitation were caused by an exponential increase in N loss (denitrification and leaching) with precipitation. We concluded that long-term experimental data were valuable in testing and refining APSIM predictions. The model can be used as a tool to assist N management guidelines in the US Midwest and we identified five avenues on how the model can add value toward

  18. Light-curve Modulation of Low-mass Stars in K2. I. Identification of 481 Fast Rotators in the Solar Neighborhood

    Science.gov (United States)

    Saylor, Dicy; Lepine, Sebastien; Crossfield, Ian; Petigura, Erik A.

    2018-01-01

    The K2 mission is targeting large numbers of nearby (d 40 mas yr‑1, V < 20). Additionally, the mission is targeting low-mass, high proper motion stars associated with the local (d < 500 pc) Galactic halo population also selected from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 26,518 of these cool main-sequence stars. We used the auto-correlation function to search for fast rotators by identifying short-period photometric modulations in the K2 light curves. We identified 481 candidate fast rotators with rotation periods <4 days that show light-curve modulations consistent with starspots. Their kinematics show low average transverse velocities, suggesting that they are part of the young disk population. A subset (13) of the fast rotators is found among those targets with colors and kinematics consistent with the local Galactic halo population and may represent stars spun up by tidal interactions in close binary systems. We further demonstrate that the M dwarf fast rotators selected from the K2 light curves are significantly more likely to have UV excess and discuss the potential of the K2 mission to identify new nearby young GKM dwarfs on the basis of their fast rotation rates. Finally, we discuss the possible use of local halo stars as fiducial, non-variable sources in the Kepler fields.

  19. Effect of solar chimney inclination angle on space flow pattern and ventilation rate

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouny, Ramadan; Korah, Nader S.A. [Department of Mechanical Power Engineering and Energy, Minia University, Minia 61111 (Egypt)

    2009-02-15

    The solar chimney is a simple and practical idea that is applied to enhance space natural ventilation. The chimney could be vertical or inclined. The chimney inclination angle is an important parameter that greatly affects space flow pattern and ventilation rate. In the present study, the effect of chimney inclination angle on air change per hour and indoor flow pattern was numerically and analytically investigated. A numerical simulation using Ansys, a FEM-based code, was used to predict flow pattern. Then the results were compared with published experimental measurements. A FORTRAN program was developed to iteratively solve the mathematical model that was obtained through an overall energy balance on the solar chimney. The analytical results showed that an optimum air flow rate value was achieved when the chimney inclination is between 45 and 70 for latitude of 28.4 . The numerically predicted flow pattern inside the space supports this finding. Moreover, in the present study a correlation to predict the air change per hour was developed. The correlation was tested within a solar intensity greater than or equal to 500 W/m{sup 2}, and chimney width from 0.1 m to 0.35 m for different inclination angles with acceptable values. (author)

  20. Rate of loss of simazine, terbuthylazine, isoproturon, and methabenzthiazuron during soil solarization.

    Science.gov (United States)

    Navarro, Simón; Bermejo, Salvador; Vela, Nuria; Hernández, Joaquín

    2009-07-22

    This paper reports the use of solar heating by polyethylene mulching for decontamination of a silty clay-loam soil polluted with herbicides. Soil solarization, a natural and hydrothermal method commonly used for disinfesting soils, was tested during the summer season on a Hipercalcic Calcisol located in Murcia (southeast Spain) for dissipation of s-triazine (simazine and terbuthylazine) and phenylurea (isoproturon and methabenzthiazuron) herbicides using low-density (LD) and high-density (HD) polyethylene (PE) film as a cover. A well-established influence of the film was observed on the dissipation of all herbicides from the soil, although the density (0.92-0.95 g/cm(3)) of the film used (LDPE and HDPE) was not significant in terms of the rate of loss. In all cases, a quick depletion during the first 2 weeks was observed, mainly for terbuthylazine. The first-order model satisfactorily explained the dissipation process, but the Hoerl and biexponential equations were more appropriate, mainly for simazine, isoproturon, and methabenzthiazuron. In all cases, herbicides disappeared at faster rates in solarized soils (DT(50) = 4-29 days) than in nonmulched soils (DT(50) = 11-35 days), especially for terbuthylazine and isoproturon.

  1. 78 FR 29131 - Solar Star California XX, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2013-05-17

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1442-000] Solar Star California XX, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Solar Star...

  2. 78 FR 29130 - Solar Star California XIX, LLC; Supplemental Notice that Initial Market-Based Rate Filing...

    Science.gov (United States)

    2013-05-17

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1441-000] Solar Star California XIX, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Solar Star...

  3. Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

    KAUST Repository

    Fiscaletti, D.; Elsinga, G. E.; Attili, Antonio; Bisetti, Fabrizio; Buxton, O. R. H.

    2016-01-01

    The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor e(i), with the vorticity vector omega, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors vertical bar e(i) . (omega) over cap vertical bar are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e(1), in contrast to the global tendency for omega to be aligned in parallelwith the intermediate strain-rate eigenvector [Hamlington et al., Phys. Fluids 20, 111703 (2008)]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment between omega and nonlocal e(1) and that the strongly swirling worms are kinematically significant to this process.

  4. Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

    KAUST Repository

    Fiscaletti, D.

    2016-10-24

    The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor e(i), with the vorticity vector omega, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors vertical bar e(i) . (omega) over cap vertical bar are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e(1), in contrast to the global tendency for omega to be aligned in parallelwith the intermediate strain-rate eigenvector [Hamlington et al., Phys. Fluids 20, 111703 (2008)]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment between omega and nonlocal e(1) and that the strongly swirling worms are kinematically significant to this process.

  5. Process control of high rate microcrystalline silicon based solar cell deposition by optical emission spectroscopy

    International Nuclear Information System (INIS)

    Kilper, T.; Donker, M.N. van den; Carius, R.; Rech, B.; Braeuer, G.; Repmann, T.

    2008-01-01

    Silicon thin-film solar cells based on microcrystalline silicon (μc-Si:H) were prepared in a 30 x 30 cm 2 plasma-enhanced chemical vapor deposition reactor using 13.56 or 40.68 MHz plasma excitation frequency. Plasma emission was recorded by optical emission spectroscopy during μc-Si:H absorber layer deposition at deposition rates between 0.5 and 2.5 nm/s. The time course of SiH * and H β emission indicated strong drifts in the process conditions particularly at low total gas flows. By actively controlling the SiH 4 gas flow, the observed process drifts were successfully suppressed resulting in a more homogeneous i-layer crystallinity along the growth direction. In a deposition regime with efficient usage of the process gas, the μc-Si:H solar cell efficiency was enhanced from 7.9 % up to 8.8 % by applying process control

  6. Measurement of rotation and strain-rate tensors by using stereoscopic PIV

    DEFF Research Database (Denmark)

    Özcan, O.; Meyer, Knud Erik; Larsen, Poul Scheel

    2004-01-01

    A simple technique is described for measuring the mean rate-of-displacement (velocity gradient) tensor in a plane by using a conventional stereoscopic PIV system. The technique involves taking PIV data in two or three closely-spaced parallel planes at different times. All components of the mean...... are presented to show the applicability of the proposed technique. The PIV cameras and light sheet optics shown in Fig. 1a are mounted on the same traverse mechanism in order to displace the measurement plane accurately. Data obtained in constant-y and -z planes are presented. Fig. 1b shows a contour plot...

  7. The solar ionisation rate deduced from Ulysses measurements and its implications to interplanetary Lyman alpha-intensity

    Science.gov (United States)

    Summanen, T.; Kyroelae, E.

    1995-01-01

    We have developed a computer code which can be used to study 3-dimensional and time-dependent effects of the solar cycle on the interplanetary (IP) hydrogen distribution. The code is based on the inverted Monte Carlo simulation. In this work we have modelled the temporal behaviour of the solar ionisation rate. We have assumed that during the most of the time of the solar cycle there is an anisotopic latitudinal structure but right at the solar maximum the anisotropy disappears. The effects of this behaviour will be discussed both in regard to the IP hydrogen distribution and IP Lyman a a-intensity.

  8. A rotation-symmetric, position-sensitive annular detector for maximum counting rates

    International Nuclear Information System (INIS)

    Igel, S.

    1993-12-01

    The Germanium Wall is a semiconductor detector system containing up to four annular position sensitive ΔE-detectors from high purity germanium (HPGe) planned to complement the BIG KARL spectrometer in COSY experiments. The first diode of the system, the Quirl-detector, has a two dimensional position sensitive structure defined by 200 Archimedes' spirals on each side with opposite orientation. In this way about 40000 pixels are defined. Since each spiral element detects almost the same number of events in an experiment the whole system can be optimized for maximal counting rates. This paper describes a test setup for a first prototype of the Quirl-detector and the results of test measurements with an α-source. The detector current and the electrical separation of the spiral elements were measured. The splitting of signals due to the spread of charge carriers produced by an incident ionizing particle on several adjacent elements was investigated in detail and found to be twice as high as expected from calculations. Its influence on energy and position resolution is discussed. Electronic crosstalk via signal wires and the influence of noise from the magnetic spectrometer has been tested under experimental conditions. Additionally, vacuum feedthroughs based on printed Kapton foils pressed between Viton seals were fabricated and tested successfully concerning their vacuum and thermal properties. (orig.)

  9. Precision measurement of the 7Be solar neutrino rate and absence of day-night asymmetry in Borexino

    International Nuclear Information System (INIS)

    Davini, S.

    2011-01-01

    Borexino, in data taking since May 2007, is the only experiment capable to perform the measurement of low-energy solar-ν. Borexino has performed the first direct measurement of the 7 Be solarrate with accuracy better than 5%. The absence of day-night asymmetry of the 7 Be solarrate was measured with a total uncertainty of 1%. Borexino results alone reject the Low Δm 2 (LOW) region of solar-ν oscillation parameters at more than 8.5 σ CL. Combined with the other solar-ν data, Borexino measurements isolate the Large Mixing Angle (LMA)- Mikheyev Smirnov Wolfenstein (MSW) solution of neutrino oscillations without assuming CPT invariance in the neutrino sector.

  10. 75 FR 76726 - San Luis Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Science.gov (United States)

    2010-12-09

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2196-000] San Luis Solar, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket... proceeding of San Luis [[Page 76727

  11. The elastic transfer model of angular rate modulation in F1-ATPase stalling and controlled rotation experiments

    Science.gov (United States)

    Volkán-Kacsó, S.

    2017-06-01

    The recent experimental, theoretical and computational advances in the field of F1-ATPase single-molecule microscopy are briefly surveyed. The role of theory is revealed in the statistical analysis, interpretation and prediction of single-molecule experimental trajectories, and in linking them with atomistic simulations. In particular, a theoretical model of elastically coupled molecular group transfer is reviewed and a detailed method for its application in stalling and controlled rotation experiments is provided. It is shown how the model can predict, using previous experiments, the rates of ligand binding/release processes (steps) and their exponential dependence on rotor angle in these experiments. The concept of Brønsted slopes is reviewed in the context of the single-molecule experiments, and the rate versus rotor angle relations are explained using the elastic model. These experimental data are treated in terms of the effect of thermodynamic driving forces on the rates assuming that the rotor shaft is elastically coupled to stator ring subunits in which the steps occur. In the application of the group transfer model on an extended angular range processes leading up to the transfer are discussed. Implications for large-scale atomistic simulation are suggested for the treatment of torque-generating steps.

  12. A review of what numerical simulations tell us about the internal rotation of the sun

    International Nuclear Information System (INIS)

    Glatzmaier, G.A.

    1986-01-01

    The simulated solar differential rotation from two independent numerical modeling efforts agree with each other and with present solar observations. The models solve the nonlinear, three-dimensional, time-dependent, anelastic equations of motion for thermal convection in a stratified, rotating, spherical shell. The simulated angular velocity in the convection zone is constant on cylinders coaxial with the rotation axis, maximum at the equator and decreasing with depth. The latitudinal variation of this angular velocity at the surface is in agreement with Doppler measurements of the solar surface rotation rate. The radial variation through the convection zone is consistent with the analysis of the rotational frequency splitting of solar oscillations. 15 refs., 5 figs

  13. Precision measurement of the (7)Be solar neutrino interaction rate in Borexino.

    Science.gov (United States)

    Bellini, G; Benziger, J; Bick, D; Bonetti, S; Bonfini, G; Buizza Avanzini, M; Caccianiga, B; Cadonati, L; Calaprice, F; Carraro, C; Cavalcante, P; Chavarria, A; D'Angelo, D; Davini, S; Derbin, A; Etenko, A; Fomenko, K; Franco, D; Galbiati, C; Gazzana, S; Ghiano, C; Giammarchi, M; Goeger-Neff, M; Goretti, A; Grandi, L; Guardincerri, E; Hardy, S; Ianni, Aldo; Ianni, Andrea; Kobychev, V; Korablev, D; Korga, G; Koshio, Y; Kryn, D; Laubenstein, M; Lewke, T; Litvinovich, E; Loer, B; Lombardi, F; Lombardi, P; Ludhova, L; Machulin, I; Manecki, S; Maneschg, W; Manuzio, G; Meindl, Q; Meroni, E; Miramonti, L; Misiaszek, M; Montanari, D; Mosteiro, P; Muratova, V; Oberauer, L; Obolensky, M; Ortica, F; Pallavicini, M; Papp, L; Peña-Garay, C; Perasso, L; Perasso, S; Pocar, A; Raghavan, R S; Ranucci, G; Razeto, A; Re, A; Romani, A; Sabelnikov, A; Saldanha, R; Salvo, C; Schönert, S; Simgen, H; Skorokhvatov, M; Smirnov, O; Sotnikov, A; Sukhotin, S; Suvorov, Y; Tartaglia, R; Testera, G; Vignaud, D; Vogelaar, R B; von Feilitzsch, F; Winter, J; Wojcik, M; Wright, A; Wurm, M; Xu, J; Zaimidoroga, O; Zavatarelli, S; Zuzel, G

    2011-09-30

    The rate of neutrino-electron elastic scattering interactions from 862 keV (7)Be solar neutrinos in Borexino is determined to be 46.0±1.5(stat)(-1.6)(+1.5)(syst) counts/(day·100  ton). This corresponds to a ν(e)-equivalent (7)Be solar neutrino flux of (3.10±0.15)×10(9)  cm(-2) s(-1) and, under the assumption of ν(e) transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 σ. A global solar neutrino analysis with free fluxes determines Φ(pp)=6.06(-0.06)(+0.02)×10(10)  cm(-2) s(-1) and Φ(CNO)Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.

  14. Solar-forced diurnal regulation of cave drip rates via phreatophyte evapotranspiration

    Directory of Open Access Journals (Sweden)

    K. Coleborn

    2016-11-01

    Full Text Available We present results of a detailed study of drip rate variations at 12 drip discharge sites in Glory Hole Cave, New South Wales, Australia. Our novel time series analysis, using the wavelet synchrosqueezed transform, reveals pronounced oscillations at daily and sub-daily frequencies occurring in 8 out of the 12 monitored sites. These oscillations were not spatially or temporally homogenous, with different drip sites exhibiting such behaviour at different times of year in different parts of the cave. We test several hypotheses for the cause of the oscillations, including variations in pressure gradients between karst and cave due to cave breathing effects or atmospheric and earth tides, variations in hydraulic conductivity due to changes in viscosity of water with daily temperature oscillations, and solar-driven daily cycles of vegetative (phreatophytic transpiration. We conclude that the only hypothesis consistent with the data and hydrologic theory is that daily oscillations are caused by solar-driven pumping by phreatophytic trees which are abundant at the site. The daily oscillations are not continuous and occur sporadically in short bursts (2–14 days throughout the year due to non-linear modification of the solar signal via complex karst architecture. This is the first indirect observation leading to the hypothesis of tree water use in cave drip water. It has important implications for karst hydrology in regards to developing a new protocol to determine the relative importance of trends in drip rate, such as diurnal oscillations, and how these trends change over timescales of weeks to years. This information can also be used to infer karst architecture. This study demonstrates the importance of vegetation on recharge dynamics, information that will inform both process-based karst models and empirical estimation approaches. Our findings support a growing body of research exploring the impact of trees on speleothem paleoclimate proxies.

  15. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    Science.gov (United States)

    Hsu, Juno; Prather, Michael J.; Cameron-Smith, Philip; Veidenbaum, Alex; Nicolau, Alex

    2017-07-01

    Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18-0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere.The Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM) applications (RRTMG-SW). Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. We compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20-40 % depending on the solar zenith angles and occur throughout the atmosphere.Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components - wavelength integration, scattering, and

  16. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    Directory of Open Access Journals (Sweden)

    J. Hsu

    2017-07-01

    Full Text Available Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18–0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere.The Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM applications (RRTMG-SW. Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. We compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20–40 % depending on the solar zenith angles and occur throughout the atmosphere.Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components – wavelength

  17. Incident solar radiation and coronary heart disease mortality rates in Europe

    International Nuclear Information System (INIS)

    Wong, Alfred

    2008-01-01

    The reported low mortality rate from coronary heart disease in Portugal, Spain, Italy, Greece, and France, to a lesser extent, has been attributed in numerous nutritional studies to the consumption of a Mediterranean-type diet. There are still many unresolved issues about the direct causal effect of the Mediterranean dietary regime on low incidence of coronary heart disease. An analysis of coronary heart disease mortality rates in Europe from a latitudinal gradient perspective has shown to have a close correlation to incident solar radiation. It is surmised that the resulting increased in situ biosynthesis of Vitamin D 3 could be the critical missing confounder in the analysis of the beneficial health outcome of the Mediterranean diet

  18. Experimental constraints on heating and cooling rates of refractory inclusions in the early solar system

    International Nuclear Information System (INIS)

    Boynton, W.V.

    1987-01-01

    The refractory inclusions in carbonaceous chondrites were the subject of considerable interest since their discovery. These inclusions contain minerals that are predicted to be some of the earliest condensates from the solar nebula, and contain a plethora of isotopic anomalies of unknown origin. Of particular interest are those coarse-grained inclusions that contain refractory metal particles (Fe, Ni, Pt, Ru, Os Ir). Experimental studies of these inclusions in terrestrial laboratories are, however, complicated because the dense particles tend to settle out of a molten or partially molten silicate material. Heating experiments in the Space Station technology and microgravity in order to observe the effects of metal nuggets (which may act as heterogeneous nucleation sites) on nucleation rates in silicate systems and to measure simultaneously the relative volatilization rate of siderophile and lithophile species. Neither experiment is possible in the terrestrial environment

  19. Energy rating of solar modules; Workshop 'vergleichender Modulertrag'

    Energy Technology Data Exchange (ETDEWEB)

    Kroeni, R. (ed.)

    2002-07-01

    This final report for the Swiss Federal Office of Energy presents the results of a workshop held in Zurich, Switzerland. The project aimed to help commercial investors in the photovoltaics area who need better information on component costs involved in photovoltaics installations. Today, solar module prices are compared using the power output under standard conditions. The authors propose that they should be compared with their energy production. The workshop, held in March 2002 in Zurich, aimed to provide an overview of existing rating methods for energy production. Various methods of comparison are discussed, including a matrix method based on electrical and meteorological measurements, a production calculation method involving efficiency measurements made for various locations and conditions as well as another approach that takes irradiance, cell temperature, spectral correction into account. A further method of calculating energy ratings from laboratory measurements is also presented, as is a review of developments in relevant standardisation areas. Various methods are compared and commented on.

  20. High-rate deposition of epitaxial layers for efficient low-temperature thin film epitaxial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Oberbeck, L.; Schmidt, J.; Wagner, T.A.; Bergmann, R.B. [Stuttgart Univ. (Germany). Inst. of Physical Electronics

    2001-07-01

    Low-temperature deposition of Si for thin-film solar cells has previously been hampered by low deposition rates and low material quality, usually reflected by a low open-circuit voltage of these solar cells. In contrast, ion-assisted deposition produces Si films with a minority-carrier diffusion length of 40 {mu}m, obtained at a record deposition rate of 0.8 {mu}m/min and a deposition temperature of 650{sup o}C with a prebake at 810{sup o}C. A thin-film Si solar cell with a 20-{mu}m-thick epitaxial layer achieves an open-circuit voltage of 622 mV and a conversion efficiency of 12.7% without any light trapping structures and without high-temperature solar cell process steps. (author)

  1. Preparation of Ga-doped ZnO films by pulsed dc magnetron sputtering with cylindrical rotating target for thin film solar cell applications

    International Nuclear Information System (INIS)

    Shin, Beom-Ki; Lee, Tae-Il; Park, Ji-Hyeon; Park, Kang-Il; Ahn, Kyung-Jun; Park, Sung-Kee; Lee, Woong; Myoung, Jae-Min

    2011-01-01

    Applicability of Ga-doped ZnO (GZO) films for thin film solar cells (TFSCs) was investigated by preparing GZO films via pulsed dc magnetron sputtering (PDMS) with rotating target. The GZO films showed improved crystallinity and increasing degree of Ga doping with increasing thickness to a limit of 1000 nm. The films also fulfilled requirements for the transparent electrodes of TFSCs in terms of electrical and optical properties. Moreover, the films exhibited good texturing potential based on etching studies with diluted HCl, which yielded an improved light trapping capability without significant degradation in electrical propreties. It is therefore suggested that the surface-textured GZO films prepared via PDMS and etching are promising candidates for indium-free transparent electrodes for TFSCs.

  2. Preparation of Ga-doped ZnO films by pulsed dc magnetron sputtering with cylindrical rotating target for thin film solar cell applications

    Science.gov (United States)

    Shin, Beom-Ki; Lee, Tae-Il; Park, Ji-Hyeon; Park, Kang-Il; Ahn, Kyung-Jun; Park, Sung-Kee; Lee, Woong; Myoung, Jae-Min

    2011-11-01

    Applicability of Ga-doped ZnO (GZO) films for thin film solar cells (TFSCs) was investigated by preparing GZO films via pulsed dc magnetron sputtering (PDMS) with rotating target. The GZO films showed improved crystallinity and increasing degree of Ga doping with increasing thickness to a limit of 1000 nm. The films also fulfilled requirements for the transparent electrodes of TFSCs in terms of electrical and optical properties. Moreover, the films exhibited good texturing potential based on etching studies with diluted HCl, which yielded an improved light trapping capability without significant degradation in electrical propreties. It is therefore suggested that the surface-textured GZO films prepared via PDMS and etching are promising candidates for indium-free transparent electrodes for TFSCs.

  3. Nonlinear two-fluid hydromagnetic waves in the solar wind: Rotational discontinuity, soliton, and finite-extent Alfven wave train solutions

    International Nuclear Information System (INIS)

    Lyu, L.H.; Kan, J.R.

    1989-01-01

    Nonlinear one-dimensional constant-profile hydromagnetic wave solutions are obtained in finite-temperature two-fluid collisionless plasmas under adiabatic equation of state. The nonlinear wave solutions can be classified according to the wavelength. The long-wavelength solutions are circularly polarized incompressible oblique Alfven wave trains with wavelength greater than hudreds of ion inertial length. The oblique wave train solutions can explain the high degree of alignment between the local average magnetic field and the wave normal direction observed in the solar wind. The short-wavelength solutions include rarefaction fast solitons, compression slow solitons, Alfven solitons and rotational discontinuities, with wavelength of several tens of ion inertial length, provided that the upstream flow speed is less than the fast-mode speed

  4. EXPLOSIVE NUCLEOSYNTHESIS IN THE NEUTRINO-DRIVEN ASPHERICAL SUPERNOVA EXPLOSION OF A NON-ROTATING 15 Msun STAR WITH SOLAR METALLICITY

    International Nuclear Information System (INIS)

    Fujimoto, Shin-ichiro; Kotake, Kei; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2011-01-01

    We investigate explosive nucleosynthesis in a non-rotating 15 M sun star with solar metallicity that explodes by a neutrino-heating supernova (SN) mechanism aided by both standing accretion shock instability (SASI) and convection. To trigger explosions in our two-dimensional hydrodynamic simulations, we approximate the neutrino transport with a simple light-bulb scheme and systematically change the neutrino fluxes emitted from the protoneutron star. By a post-processing calculation, we evaluate abundances and masses of the SN ejecta for nuclei with a mass number ≤70, employing a large nuclear reaction network. Aspherical abundance distributions, which are observed in nearby core-collapse SN remnants, are obtained for the non-rotating spherically symmetric progenitor, due to the growth of a low-mode SASI. The abundance pattern of the SN ejecta is similar to that of the solar system for models whose masses range between (0.4-0.5) M sun of the ejecta from the inner region (≤10, 000 km) of the precollapse core. For the models, the explosion energies and the 56 Ni masses are ≅ 10 51 erg and (0.05-0.06) M sun , respectively; their estimated baryonic masses of the neutron star are comparable to the ones observed in neutron-star binaries. These findings may have little uncertainty because most of the ejecta is composed of matter that is heated via the shock wave and has relatively definite abundances. The abundance ratios for Ne, Mg, Si, and Fe observed in the Cygnus loop are reproduced well with the SN ejecta from an inner region of the 15 M sun progenitor.

  5. Polymer:Nonfullerene Bulk Heterojunction Solar Cells with Exceptionally Low Recombination Rates

    KAUST Repository

    Gasparini, Nicola; Salvador, Michael; Heumueller, Thomas; Richter, Moses; Classen, Andrej; Shrestha, Shreetu; Matt, Gebhard J.; Holliday, Sarah; Strohm, Sebastian; Egelhaaf, Hans-Joachim; Wadsworth, Andrew; Baran, Derya; McCulloch, Iain; Brabec, Christoph J.

    2017-01-01

    Organic semiconductors are in general known to have an inherently lower charge carrier mobility compared to their inorganic counterparts. Bimolecular recombination of holes and electrons is an important loss mechanism and can often be described by the Langevin recombination model. Here, the device physics of bulk heterojunction solar cells based on a nonfullerene acceptor (IDTBR) in combination with poly(3-hexylthiophene) (P3HT) are elucidated, showing an unprecedentedly low bimolecular recombination rate. The high fill factor observed (above 65%) is attributed to non-Langevin behavior with a Langevin prefactor (β/βL) of 1.9 × 10−4. The absence of parasitic recombination and high charge carrier lifetimes in P3HT:IDTBR solar cells inform an almost ideal bimolecular recombination behavior. This exceptional recombination behavior is explored to fabricate devices with layer thicknesses up to 450 nm without significant performance losses. The determination of the photoexcited carrier mobility by time-of-flight measurements reveals a long-lived and nonthermalized carrier transport as the origin for the exceptional transport physics. The crystalline microstructure arrangement of both components is suggested to be decisive for this slow recombination dynamics. Further, the thickness-independent power conversion efficiency is of utmost technological relevance for upscaling production and reiterates the importance of understanding material design in the context of low bimolecular recombination.

  6. Polymer:Nonfullerene Bulk Heterojunction Solar Cells with Exceptionally Low Recombination Rates

    KAUST Repository

    Gasparini, Nicola

    2017-09-01

    Organic semiconductors are in general known to have an inherently lower charge carrier mobility compared to their inorganic counterparts. Bimolecular recombination of holes and electrons is an important loss mechanism and can often be described by the Langevin recombination model. Here, the device physics of bulk heterojunction solar cells based on a nonfullerene acceptor (IDTBR) in combination with poly(3-hexylthiophene) (P3HT) are elucidated, showing an unprecedentedly low bimolecular recombination rate. The high fill factor observed (above 65%) is attributed to non-Langevin behavior with a Langevin prefactor (β/βL) of 1.9 × 10−4. The absence of parasitic recombination and high charge carrier lifetimes in P3HT:IDTBR solar cells inform an almost ideal bimolecular recombination behavior. This exceptional recombination behavior is explored to fabricate devices with layer thicknesses up to 450 nm without significant performance losses. The determination of the photoexcited carrier mobility by time-of-flight measurements reveals a long-lived and nonthermalized carrier transport as the origin for the exceptional transport physics. The crystalline microstructure arrangement of both components is suggested to be decisive for this slow recombination dynamics. Further, the thickness-independent power conversion efficiency is of utmost technological relevance for upscaling production and reiterates the importance of understanding material design in the context of low bimolecular recombination.

  7. Design of a deployment rotation mechanism for microsatellite

    NARCIS (Netherlands)

    Abdelal, G.F.; Bakr Elhady, A.; Kassab, M.

    2009-01-01

    Solar array rotation mechanism provides a hinged joint between the solar panel and satellite body, smooth rotation of the solar array into deployed position and its fixation in this position. After unlocking of solar panel (while in orbit), rotation bracket turns towards ready-to-work position under

  8. In-line high-rate evaporation of aluminum for the metallization of silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mader, Christoph Paul

    2012-07-11

    This work focuses on the in-line high-rate evaporation of aluminum for contacting rear sides of silicon solar cells. The substrate temperature during the deposition process, the wafer bow after deposition, and the electrical properties of evaporated contacts are investigated. Furthermore, this work demonstrates for the first time the formation of aluminum-doped silicon regions by the in-line high-rate evaporation of aluminum without any further temperature treatment. The temperature of silicon wafers during in-line high-rate evaporation of aluminum is investigated in this work. The temperatures are found to depend on the wafer thickness W, the aluminum layer thickness d, and on the wafer emissivity {epsilon}. Two-dimensional finite-element simulations reproduce the measured peak temperatures with an accuracy of 97%. This work also investigates the wafer bow after in-line high-rate evaporation and shows that the elastic theory overestimates the wafer bow of planar Si wafers. The lower bow is explained with plastic deformation in the Al layer. Due to the plastic deformation only the first 79 K in temperature decrease result in a bow formation. Furthermore the electrical properties of evaporated point contacts are examined in this work. Parameterizations for the measured saturation currents of contacted p-type Si wafers and of contacted boron-diffused p{sup +}-type layers are presented. The contact resistivity of the deposited Al layers to silicon for various deposition processes and silicon surface concentrations are presented and the activation energy of the contact formation is determined. The measured saturation current densities and contact resistivities of the evaporated contacts are used in one-dimensional numerical Simulations and the impact on energy conversion efficiency of replacing a screen-printed rear side by an evaporated rear side is presented. For the first time the formation of aluminum-doped p{sup +}-type (Al-p{sup +}) silicon regions by the in

  9. Empirically observed learning rates for concentrating solar power and their responses to regime change

    Science.gov (United States)

    Lilliestam, Johan; Labordena, Mercè; Patt, Anthony; Pfenninger, Stefan

    2017-07-01

    Concentrating solar power (CSP) capacity has expanded slower than other renewable technologies and its costs are still high. Until now, there have been too few CSP projects to derive robust conclusions about its cost development. Here we present an empirical study of the cost development of all operating CSP stations and those under construction, examining the roles of capacity growth, industry continuity, and policy support design. We identify distinct CSP expansion phases, each characterized by different cost pressure in the policy regime and different industry continuity. In 2008-2011, with low cost pressure and following industry discontinuity, costs increased. In the current phase, with high cost pressure and continuous industry development, costs decreased rapidly, with learning rates exceeding 20%. Data for projects under construction suggest that this trend is continuing and accelerating. If support policies and industrial structure are sustained, we see no near-term factors that would hinder further cost decreases.

  10. Electrochemical reaction rates in a dye sentisised solar cell - the iodide/tri-iodide redox system

    DEFF Research Database (Denmark)

    Bay, Lasse; West, Keld; Winter-Jensen, Bjørn

    2006-01-01

    The electrochemical reaction rate of the redox couple iodide / tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide / tri......-iodide couple should be fast at the counter electrode, i.e. this electrode must have a high catalytic activity towards the redox couple, and the same reaction must be slow on the photo electrode. The catalytic activity is investigated for platinum, poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy......), and polyaniline (PANI) - all deposited onto fluorine doped tin oxide (FTO) glass. Both Pt and PEDOT are found to have sufficiently high catalytic activities for practical use as counter electrode in DSSC. The reaction resistance on FTO and anatase confirmed the beneficial effect of a compact anatase layer on top...

  11. 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...

  12. Earth Rotation

    Science.gov (United States)

    Dickey, Jean O.

    1995-01-01

    The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.

  13. Solar magnetism: a new look

    International Nuclear Information System (INIS)

    Golub, L.

    1981-01-01

    With the growing evidence for the ubiquity of magnetic fields, researchers feel a growing need for an adequate theory for the generation of such fields in nature. This article looks at the sun and its magnetic fields. The fundamental property that must be explained aside from the existence of magnetic fields is the solar cycle. The traditional picture of the solar cycle has three primary components: (1) solar activity; (2) latitude migration; and (3) Hale's law and reversal of polarity. The aspects of internal motion which can generate magnetic fields and cycles of activity like those observed are discussed. There are two major elements to the flow patterns of the sun. More important than the visible differential rotation of solar surface is the belief that the sun's interior rotates faster than the surface. It is this mechanism which probably produces the magnetic fields which bubble up from interior. It's also possible to show that this mechanism can produce the migration of solar activity. The reversal of polarity is explained by convection zones and sun's rotation. Due to x-ray imaging and improved magnetic field measurements, it has been observed that enormous quantities of magnetic flux emerge from solar interior in form of very small regions. This data along with rocket data show that the rate of generation of magnetic flux does not change during a solar cycle - instead, the observed cycle represents a shift from large emerging regions to numerous small regions and back again

  14. Extension of the flow-rate-of-strain tensor formulation of plasma rotation theory to non-axisymmetric tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W. M. [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Bae, C. [National Fusion Research Institute, Daejoen (Korea, Republic of)

    2015-06-15

    A systematic formalism for the calculation of rotation in non-axisymmetric tokamaks with 3D magnetic fields is described. The Braginskii Ωτ-ordered viscous stress tensor formalism, generalized to accommodate non-axisymmetric 3D magnetic fields in general toroidal flux surface geometry, and the resulting fluid moment equations provide a systematic formalism for the calculation of toroidal and poloidal rotation and radial ion flow in tokamaks in the presence of various non-axisymmetric “neoclassical toroidal viscosity” mechanisms. The relation among rotation velocities, radial ion particle flux, ion orbit loss, and radial electric field is discussed, and the possibility of controlling these quantities by producing externally controllable toroidal and/or poloidal currents in the edge plasma for this purpose is suggested for future investigation.

  15. Rates and timing of vertical-axis block rotations across the Sierra Nevada-Walker Lane transition in the Bodie Hills

    Science.gov (United States)

    Rood, D. H.; Herman, S.; Burbank, D.; Bogue, S.

    2008-12-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotation across the Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. In zones of continental deformation, block rotations are an important mechanism for permanent stain accommodation, and thus may be crucial to testing geodetic block models and resolving geologic-geodetic slip discrepancies. In our study, data included in the paleomagetic site means are high quality AF demagnetization results (least squared fits that generally include 5-7 points with MAD values less than 1). Thermal demagnetization results match the AF directions, and both thermal demag and rockmag results indicate strong ChRM, mostly carried by single domain magnetite. The site means used to calculate the VGPs all have a95 values less than 10 (mostly 2-5) and include 6-11 sites each. Each site (and thus site mean) has a reasonably well-known structural correction. The VGP scatter values range from 12 to 16 degrees, indicating that they include appropriate secular variation. The mean declinations and 95 percent confidence limits for each VGP timeslice are statistically distinct from one another (71 ± 9, 39 ± 13, and 11 ± 11 degrees). The slope of a linear regression fit to the age versus declination data gives a rate of vertical axis block rotation of approximately 3-4 degrees/Myr. Fitting two separate lines to the age vs. declination data would indicate an increase in the rates of rotation since ~10 Ma. Two possible interpretations of the data are: (1) the rotations began during or before the Middle Miocene, or (2) rates of rotation were high initially (e.g. ~10 Ma) and decelerated until the Pliocene. These data have implications for the (1) timing and spatial extent of distributed strain accumulation related to the initiation of the San Andreas Fault-Eastern California Shear Zone-Walker Lane transform plate boundary, (2) transfer of transform plate boundary

  16. A new picture for the internal rotation of the sun

    International Nuclear Information System (INIS)

    Morrow, C.A.

    1988-01-01

    This thesis describes a helioseismic quest to determine the angular velocity inside the Sun as a function of depth and latitude. The author analyzes rotational frequency splittings extracted from 15 days of full-disk observations of the solar acoustic oscillations (1 = 15-99) obtained with the Fourier Tachometer (a Doppler analyzing instrument design by Tim Brown). She has compared the observed frequency splittings to those generated by several different physically-motivated models for the solar internal angular velocity. She also introduces convenient preliminary analysis techniques, which require no formal computations and which guide the choices of rotation models. He analysis suggests that the differential rotation in latitude observed at the solar surface pervades the convection zone and perhaps even deeper layers. Thus, the convection zone appears to contain little or no radial gradient of angular velocity. The analysis further indicates that the angular velocity of the outer portion of the radiative interior is constant, or nearly so, at a value that is intermediate between the relatively fast equatorial rate and the slower polar rate of the surface profile. This new picture of the Sun's internal rotation implies that a significant radial gradient exists only in a transitional layer between the convection zone and the radiative interior. This model has intriguing implications for the solar dynamo, for the current distribution and transport of angular momentum, and for the current distribution and transport of angular momentum, and for the rotational and evolutionary history of the Sun

  17. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

  18. Rotational history of the sun: Spin-down of the interior by circulation currents and fluid instabilities

    International Nuclear Information System (INIS)

    Endal, A.S.; Sofia, S.

    1980-01-01

    A number of astronomical observations show that solar-type stars begin the main-sequence stage with surface rotation rates which are much greater than that of the sun. The subsequent decrease in the surface rotation rate is due to the braking torque exerted by magnetically-coupled mass loss (the solar wind). The direct braking action of the solar wind should be confined to the convective envelope so the rotation of the radiative interior remains an open question. After reviewing the relevant astronomical data, we describe how angular momentum could be transported out of the radiative interior by fluid instabilities and estimate the time scales for such transport. This picture is used to construct an evolutionary model of the sun, which predicts the present rotation of the radiative interior. The results of such a model are interpreted in terms of the measured oblateness of the solar surface

  19. Evaluation of computed tomography coronary angiography in patients with a high heart rate using 16-slice spiral computed tomography with 0.37-s gantry rotation time

    International Nuclear Information System (INIS)

    Zhang, Shi-Zheng; Hu, Xiu-Hua; Zhang, Qiao-Wei; Huang, Wen-Xin

    2005-01-01

    The aim of our study is to evaluate computed tomography (CT) coronary angiography in patients with a high heart rate using 16-slice spiral CT with 0.37-s gantry rotation time. We compare the image quality of patients whose heart rates were over 70 beats per minute (bpm) with that of patients whose heart rates were 70 bpm or less. Sixty patients with various heart rates underwent retrospectively ECG-gated multislice spiral CT (MSCT) coronary angiography. Two experienced observers who were blind to the heart rates of the patients evaluated all the MSCT coronary angiographic images and calculated the assessable segments. A total of 620 out of 891 (69.6%) segments were satisfactorily visualized. On average, 10.3 coronary artery segments per patient could be evaluated. In 36 patients whose heart rates were below 70 bpm [mean 62.2 bpm±5.32 (standard deviation, SD)], the number of assessable segments was 10.72±2.02 (SD). In the other 24 patients whose heart rates were above 70 bpm [mean 78.6 bpm±8.24 (SD)], the corresponding number was 9.75±1.74 (SD). No statistically significant difference was found in these two subgroups' t test, P>0.05. The new generation of 16-slice spiral CT with 0.37-s rotation time can satisfactorily evaluate the coronary arteries of patients with high heart rates (above 70 bpm, up to 102 bpm). (orig.)

  20. The Rotation Rates of Massive Stars: The Role of Binary Interaction through Tides, Mass Transfer, and Mergers

    NARCIS (Netherlands)

    de Mink, S.E.; Langer, N.; Izzard, R.G.; Sana, H.; de Koter, A.

    2013-01-01

    Rotation is thought to be a major factor in the evolution of massive stars—especially at low metallicity—with consequences for their chemical yields, ionizing flux, and final fate. Deriving the birth spin distribution is of high priority given its importance as a constraint on theories of massive

  1. Friction Surface Cladding of AA1050 on AA2024-T351; influence of clad layer thickness and tool rotation rate

    NARCIS (Netherlands)

    Liu, Shaojie; Bor, Teunis Cornelis; Geijselaers, Hubertus J.M.; Akkerman, Remko

    2015-01-01

    Friction Surfacing Cladding (FSC) is a recently developed solid state process to deposit thin metallic clad layers on a substrate. The process employs a rotating tool with a central opening to supply clad material and support the distribution and bonding of the clad material to the substrate. The

  2. Rating of roofs’ surfaces regarding their solar potential and suitability for PV systems, based on LiDAR data

    International Nuclear Information System (INIS)

    Lukač, Niko; Žlaus, Danijel; Seme, Sebastijan; Žalik, Borut; Štumberger, Gorazd

    2013-01-01

    Highlights: ► A new method for estimating and rating buildings roofs’ solar potential is presented. ► Considering LiDAR geospatial data together with pyranometer measurements. ► Use of multi-resolution shadowing model with new heuristic vegetation shadowing. ► High correlation between estimated solar potential and onsite measurements. -- Abstract: The roof surfaces within urban areas are constantly attracting interest regarding the installation of photovoltaic systems. These systems can improve self-sufficiency of electricity supply, and can help to decrease the emissions of greenhouse gases throughout urban areas. Unfortunately, some roof surfaces are unsuitable for installing photovoltaic systems. This presented work deals with the rating of roof surfaces within urban areas regarding their solar potential and suitability for the installation of photovoltaic systems. The solar potential of a roof’s surface is determined by a new method that combines extracted urban topography from LiDAR data with the pyranometer measurements of global and diffuse solar irradiances. Heuristic annual vegetation shadowing and a multi-resolution shadowing model, complete the proposed method. The significance of different influential factors (e.g. shadowing) was analysed extensively. A comparison between the results obtained by the proposed method and measurements performed on an actual PV power plant showed a correlation agreement of 97.4%.

  3. High efficiency high rate microcrystalline silicon thin-film solar cells deposited at plasma excitation frequencies larger than 100 MHz

    Czech Academy of Sciences Publication Activity Database

    Strobel, C.; Leszczynska, B.; Merkel, U.; Kuske, J.; Fischer, D.D.; Albert, M.; Holovský, Jakub; Michard, S.

    2015-01-01

    Roč. 143, Dec (2015), 347-353 ISSN 0927-0248 R&D Projects: GA MŠk 7E12029 EU Projects: European Commission(XE) 283501 - Fast Track Institutional support: RVO:68378271 Keywords : VHF * PECVD * microcrystalline silicon * solar cell * high rate * high efficiency Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.732, year: 2015

  4. Exergy analysis of integrated photovoltaic thermal solar water heater under constant flow rate and constant collection temperature modes

    NARCIS (Netherlands)

    Tiwari, A.; Dubey, Swapnil; Sandhu, G.S.; Sodha, M.S.; Anwar, S.I.

    2009-01-01

    In this communication, an analytical expression for the water temperature of an integrated photovoltaic thermal solar (IPVTS) water heater under constant flow rate hot water withdrawal has been obtained. Analysis is based on basic energy balance for hybrid flat plate collector and storage tank,

  5. 77 FR 36528 - K Road Modesto Solar LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2012-06-19

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-1995-000] K Road Modesto Solar LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of K Road...

  6. 78 FR 34373 - Campo Verde Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2013-06-07

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-1541-000] Campo Verde Solar, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Campo Verde...

  7. 76 FR 63614 - Agua Caliente Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2011-10-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-21-000] Agua Caliente Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Agua...

  8. 75 FR 80487 - Paradise Solar Urban Renewal, L.L.C.; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2010-12-22

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2365-000] Paradise...-referenced proceeding of Paradise Solar Urban Renewal, L.L.C.'s application for market-based rate authority... electronic submission of protests and interventions in lieu of paper, using the FERC Online links at http...

  9. Effects of suspended particles on the rate of mass transfer to a rotating disk electrode. [Ferric cyanide

    Energy Technology Data Exchange (ETDEWEB)

    Roha, D.J.

    1981-06-01

    Limiting currents for the reduction of ferric cyanide at a rotating disk were determined in the presence of 0 to 40 percent by volume of spherical glass beads. Experiments were conducted with six different particle diameters, and with rotation speeds in the range of 387 to 270 rpm, usong both a 0.56 cm and a 1.41 cm radius disk electrode. It was established that at a given rpm upon addition of glass beads in the limiting current, i/sub L/, may increase to more than three times its value without solids. This increase in limiting current density is greater at high rotation speeds and with the larger disk electrode. i/sub L/ as a function of particle diameter yields at maximum at approx. 10 ..mu..m. Two mass transfer models are offered to explain this behavior, both of which assume that the beads are in contact with the disk electrode and moving parallel to its surface. In the surface renewal model it is assumed that complete mixing takes place with the passage of each bead and the boundary layer is replaced with fresh bulk solution. While with the particle film model it is assumed the bead and a clinging film of fluid rotate together. The film promotes mass transfer by alternately absorbing and desorbing the diffusing species. The particle film model best explains the observed behavior of the limiting current density. Calculations of stirring power required verses i/sub L/ observed, show that adding beads to increase i/sub L/ consumes less additional power than simply increasing the rotation speed alone and even permits a decrease in the amount of stirring energy required per unit reactant consumed, at limiting current conditions.

  10. 26Al yields from rotating Wolf--Rayet star models

    OpenAIRE

    Vuissoz, C.; Meynet, G.; Knoedlseder, J.; Cervino, M.; Schaerer, D.; Palacios, A.; Mowlavi, N.

    2003-01-01

    We present new $^{26}$Al stellar yields from rotating Wolf--Rayet stellar models which, at solar metallicity, well reproduce the observed properties of the Wolf-Rayet populations. These new yields are enhanced with respect to non--rotating models, even with respect to non--rotating models computed with enhanced mass loss rates. We briefly discuss some implications of the use of these new yields for estimating the global contribution of Wolf-Rayet stars to the quantity of $^{26}$Al now present...

  11. Solar Energy Deposition Rates in the Mesosphere Derived from Airglow Measurements: Implications for the Ozone Model Deficit Problem

    Science.gov (United States)

    Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura

    2000-01-01

    We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-microns oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat-budget.gats-inc.com.

  12. An algorithm to evaluate solar irradiance and effective dose rates using spectral UV irradiance at four selected wavelengths

    International Nuclear Information System (INIS)

    Anav, A.; Rafanelli, C.; Di Menno, I.; Di Menno, M.

    2004-01-01

    The paper shows a semi-analytical method for environmental and dosimetric applications to evaluate, in clear sky conditions, the solar irradiance and the effective dose rates for some action spectra using only four spectral irradiance values at selected wavelengths in the UV-B and UV-A regions (305, 320, 340 and 380 nm). The method, named WL4UV, is based on the reconstruction of an approximated spectral irradiance that can be integrated, to obtain the solar irradiance, or convoluted with an action spectrum to obtain an effective dose rate. The parameters required in the algorithm are deduced from archived solar spectral irradiance data. This database contains measurements carried out by some Brewer spectrophotometers located in various geographical positions, at similar altitudes, with very different environmental characteristics: Rome (Italy), Ny Aalesund (Svalbard Islands (Norway)) and Ushuaia (Tierra del Fuego (Argentina)). To evaluate the precision of the method, a double test was performed with data not used in developing the model. Archived Brewer measurement data, in clear sky conditions, from Rome and from the National Science Foundation UV data set in San Diego (CA, USA) and Ushuaia, where SUV 100 spectro-radiometers operate, were drawn randomly. The comparison of measured and computed irradiance has a relative deviation of about ±2%. The effective dose rates for action spectra of Erythema, DNA and non-Melanoma skin cancer have a relative deviation of less than ∼20% for solar zenith angles <50 deg.. (authors)

  13. Change in General Relativistic precession rates due to Lidov-Kozai oscillations in the Solar System

    Science.gov (United States)

    Sekhar, Aswin; Asher, David J.; Werner, Stephanie C.; Vaubaillon, Jeremie; Li, Gongjie

    2017-04-01

    permissible in nature. A real solar system body in this intermediate state is identified using compiled observational records from IAU-Minor Planet Center, Cometary Catalogue, IAU-Meteor Data Center and performing analytical plus numerical tests on them. This intermediate state brings up the interesting possibility of drastic changes in GR precession rates (at some points peaking to about 60 times that of Mercury's GR precession) during orbital evolution due to sungrazing and sun colliding phases induced by the LK mechanism, thus combining both these important effects in a unique and dynamically interesting way. Comet 96P/Machholz 1 stands out as the only real body identified (from our simulations) to be exhibiting these interesting traits, as well as inclination flips, in the near future. Both these phenomena complimenting and co-existing at the same time has interesting implications in the long term impact studies of small bodies in general.

  14. Effect of solar radiation on the lipid characterization of biomass cultivated in high-rate algal ponds using domestic sewage.

    Science.gov (United States)

    Assemany, Paula Peixoto; Calijuri, Maria Lúcia; Santiago, Anibal da Fonseca; do Couto, Eduardo de Aguiar; Leite, Mauricio de Oliveira; Sierra, Jose Jovanny Bermudez

    2014-01-01

    The objective of this paper is to compare the lipid content and composition ofbiomass produced by a consortium of microalgae and bacteria, cultivated under different solar radiation intensities and tropical conditions in pilot-scale high-rate ponds (HRPs) using domestic sewage as culture medium. The treatment system consisted of an upflow anaerobic sludge blanket reactor followed by UV disinfection and six HRPs covered with shading screens that blocked 9%, 18%, 30%, 60% and 80% of the solar radiation. The total lipid content does not vary significantly among the units, showing a medium value of 9.5%. The results show that blocking over 30% of the solar radiation has a negative effect on the lipid productivity. The units with no shading and with 30% and 60% of solar radiation blocking have statistically significant lipid productivities, varying from 0.92 to 0.96 gm(-2) day(-1). Besides radiation, other variables such as volatile suspended solids and chlorophyll-a are able to explain the lipid accumulation. The lipid profile has a predominance of C16, C18:1 and C18:3 acids. The unsaturation of fatty acids increases with the reduction in solar radiation. On the other hand, the effect of polyunsaturation is not observed, which is probably due to the presence of a complex and diverse biomass.

  15. Impact of Federal tax policy and electric utility rate schedules upon the solar building/electric utility interface. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, S.L.; Wirtshafter, R.M.; Abrash, M.; Anderson, B.; Sullivan, P.; Kohler, J.

    1978-10-01

    An analysis is performed to show that a utility solar-passive strategy can be used rather effectively in aiding the utility to obtain more efficient load factors and lower costs. The objectives are to determine the impact of active and passive solar energy designs for space conditioning and hot water heating for the residential sector upon the diurnal and annual load curves for several utilities, to assess the effect of present utility pricing policies, and to examine alternative pricing schemes, as well as Federal and state tax credits, as they may affect the optimal sizing and configuration of active solar and passive solar building components. The methodology, the systems model, an overall building design, building cost determination, and a description of TRNSYS are presented. The major parameters discussed that distinguish variation in the cost-effectiveness of particular building design fall into 5 categories: the weather, building configurations, building costs, utility costs and rates, and financial parameters (inclusive of tax credits for solar and energy conservation investment). Five utilities are studied: Colorado Springs Department of Public Utilities; Public Service Co. of New Mexico; New England Electric System; Pacific Gas and Electric; and Georgia Power Co.

  16. A Generalized Approach to Model the Spectra and Radiation Dose Rate of Solar Particle Events on the Surface of Mars

    Science.gov (United States)

    Guo, Jingnan; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; McDole, Thoren; Kühl, Patrick; Appel, Jan C.; Matthiä, Daniel; Krauss, Johannes; Köhler, Jan

    2018-01-01

    For future human missions to Mars, it is important to study the surface radiation environment during extreme and elevated conditions. In the long term, it is mainly galactic cosmic rays (GCRs) modulated by solar activity that contribute to the radiation on the surface of Mars, but intense solar energetic particle (SEP) events may induce acute health effects. Such events may enhance the radiation level significantly and should be detected as immediately as possible to prevent severe damage to humans and equipment. However, the energetic particle environment on the Martian surface is significantly different from that in deep space due to the influence of the Martian atmosphere. Depending on the intensity and shape of the original solar particle spectra, as well as particle types, the surface spectra may induce entirely different radiation effects. In order to give immediate and accurate alerts while avoiding unnecessary ones, it is important to model and well understand the atmospheric effect on the incoming SEPs, including both protons and helium ions. In this paper, we have developed a generalized approach to quickly model the surface response of any given incoming proton/helium ion spectra and have applied it to a set of historical large solar events, thus providing insights into the possible variety of surface radiation environments that may be induced during SEP events. Based on the statistical study of more than 30 significant solar events, we have obtained an empirical model for estimating the surface dose rate directly from the intensities of a power-law SEP spectra.

  17. Surprisingly different star-spot distributions on the near equal-mass equal-rotation-rate stars in the M dwarf binary GJ 65 AB

    Science.gov (United States)

    Barnes, J. R.; Jeffers, S. V.; Haswell, C. A.; Jones, H. R. A.; Shulyak, D.; Pavlenko, Ya. V.; Jenkins, J. S.

    2017-10-01

    We aim to understand how stellar parameters such as mass and rotation impact the distribution of star-spots on the stellar surface. To this purpose, we have used Doppler imaging to reconstruct the surface brightness distributions of three fully convective M dwarfs with similar rotation rates. We secured high cadence spectral time series observations of the 5.5 au separation binary GJ 65, comprising GJ 65A (M5.5V, Prot = 0.24 d) and GJ 65B (M6V, Prot = 0.23 d). We also present new observations of GJ 791.2A (M4.5V, Prot = 0.31 d). Observations of each star were made on two nights with UVES, covering a wavelength range from 0.64 - 1.03μm. The time series spectra reveal multiple line distortions that we interpret as cool star-spots and which are persistent on both nights suggesting stability on the time-scale of 3 d. Spots are recovered with resolutions down to 8.3° at the equator. The global spot distributions for GJ 791.2A are similar to observations made a year earlier. Similar high latitude and circumpolar spot structure is seen on GJ 791.2A and GJ 65A. However, they are surprisingly absent on GJ 65B, which instead reveals more extensive, larger, spots concentrated at intermediate latitudes. All three stars show small amplitude latitude-dependent rotation that is consistent with solid body rotation. We compare our measurements of differential rotation with previous Doppler imaging studies and discuss the results in the wider context of other observational estimates and recent theoretical predictions.

  18. Excellent healing rates and patient satisfaction after arthroscopic repair of medium to large rotator cuff tears with a single-row technique augmented with bone marrow vents.

    Science.gov (United States)

    Dierckman, Brian D; Ni, Jake J; Karzel, Ronald P; Getelman, Mark H

    2018-01-01

    This study evaluated the repair integrity and patient clinical outcomes following arthroscopic rotator cuff repair of medium to large rotator cuff tears using a single-row technique consisting of medially based, triple-loaded anchors augmented with bone marrow vents in the rotator cuff footprint lateral to the repair. This is a retrospective study of 52 patients (53 shoulders) comprising 36 males and 16 females with a median age of 62 (range 44-82) with more than 24-month follow-up, tears between 2 and 4 cm in the anterior-posterior dimension and utilizing triple-loaded anchors. Mann-Whitney test compared Western Ontario Rotator Cuff (WORC) outcome scores between patients with healed and re-torn cuff repairs. Multivariate logistic regression analysed association of variables with healing status and WORC score. Cuff integrity was assessed on MRI, read by a musculoskeletal fellowship-trained radiologist. Magnetic resonance imaging (MRI) demonstrated an intact repair in 48 of 53 shoulders (91%). The overall median WORC score was 95.7 (range 27.6-100.0). A significant difference in WORC scores were seen between patients with healed repairs 96.7 (range 56.7-100.0) compared with a re-tear 64.6 (27.6-73.8), p rotator cuff tears using a triple-loaded single-row repair augmented with bone marrow vents resulted in a 91% healing rate by MRI and excellent patient reported clinical outcomes comparable to similar reported results in the literature. IV.

  19. Rate of production of cosmogenic isotopes in the past and solar activity

    International Nuclear Information System (INIS)

    Kocharov, G.E.; Dergachev, V.A.; Gordeichik, N.I.; Ioffe, A.F.

    1975-01-01

    The available experimental data on abundances of 14 C, 10 Be and 26 Al in materials with known ages are analyzed with the aim of determining of solar activity in the past. Based on the authors results on the abundances of 14 C in the tree rings it is shown that concentration of radiocarbon in atmosphere is changed with the period of approximately 60 years, amplitude approcimately 1% and phase shift relatively to solar activity of approximately 10 years. (orig./WBU) [de

  20. Mass-loss Rates from Coronal Mass Ejections: A Predictive Theoretical Model for Solar-type Stars

    Energy Technology Data Exchange (ETDEWEB)

    Cranmer, Steven R. [Department of Astrophysical and Planetary Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309 (United States)

    2017-05-10

    Coronal mass ejections (CMEs) are eruptive events that cause a solar-type star to shed mass and magnetic flux. CMEs tend to occur together with flares, radio storms, and bursts of energetic particles. On the Sun, CME-related mass loss is roughly an order of magnitude less intense than that of the background solar wind. However, on other types of stars, CMEs have been proposed to carry away much more mass and energy than the time-steady wind. Earlier papers have used observed correlations between solar CMEs and flare energies, in combination with stellar flare observations, to estimate stellar CME rates. This paper sidesteps flares and attempts to calibrate a more fundamental correlation between surface-averaged magnetic fluxes and CME properties. For the Sun, there exists a power-law relationship between the magnetic filling factor and the CME kinetic energy flux, and it is generalized for use on other stars. An example prediction of the time evolution of wind/CME mass-loss rates for a solar-mass star is given. A key result is that for ages younger than about 1 Gyr (i.e., activity levels only slightly higher than the present-day Sun), the CME mass loss exceeds that of the time-steady wind. At younger ages, CMEs carry 10–100 times more mass than the wind, and such high rates may be powerful enough to dispel circumstellar disks and affect the habitability of nearby planets. The cumulative CME mass lost by the young Sun may have been as much as 1% of a solar mass.

  1. Solar tracking system

    Science.gov (United States)

    White, P. R.; Scott, D. R. (Inventor)

    1981-01-01

    A solar tracker for a solar collector is described in detail. The collector is angularly oriented by a motor wherein the outputs of two side-by-side photodetectors are discriminated as to three ranges: a first corresponding to a low light or darkness condition; a second corresponding to light intensity lying in an intermediate range; and a third corresponding to light above an intermediate range, direct sunlight. The first output drives the motor to a selected maximum easterly angular position; the second enables the motor to be driven westerly at the Earth rotational rate; and the third output, the separate outputs of the two photodetectors, differentially controls the direction of rotation of the motor to effect actual tracking of the Sun.

  2. Regional wall thickening in gated myocardial perfusion SPECT in a Japanese population: effect of sex, radiotracer, rotation angles and frame rates

    Energy Technology Data Exchange (ETDEWEB)

    Akhter, Nasima; Nakajima, Kenichi; Okuda, Koichi; Matsuo, Shinro; Yoneyama, Tatsuya; Taki, Junichi; Kinuya, Seigo [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa, Ishikawa (Japan)

    2008-09-15

    Gated single-photon emission computed tomography (SPECT) imaging of myocardium by {sup 99m}Tc and {sup 201}Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT. Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution. WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by {sup 99m}Tc-labelled tracers than in {sup 201}Tl. Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique. (orig.)

  3. The search for possible time variations in Davis' measurements of the argon production rate in the solar neutrino experiment

    International Nuclear Information System (INIS)

    Haubold, H.J.; Gerth, E.

    1985-01-01

    With the gradual accumulation of experimental data in the solar neutrino experiment of Davis and collaborators (runs 18-74 for 1970-1982), the question, whether there are time variations of the solar neutrino flux, is of renewed interest. We discuss the mathematical-numerical methods applied to the statistical analysis of Davis' argon-37 production rate up till now known in the literature. These methods are characterized by the arbitrary arrangement of the Davis data in a time series. We perform a certain Fourier transformation for unequally-spaced time series of the measuring data of the argon-37 production rate, discuss the discovered periods and give significance criteria with respect to each period. We find that all periods discussed in the literature are contained in our series of periods. Pointing out the more mathematical character of the time series analysis we emphasize the predominant significance of the detected periods. (author)

  4. The Effect of Cumulus Cloud Field Anisotropy on Domain-Averaged Solar Fluxes and Atmospheric Heating Rates

    Science.gov (United States)

    Hinkelman, Laura M.; Evans, K. Franklin; Clothiaux, Eugene E.; Ackerman, Thomas P.; Stackhouse, Paul W., Jr.

    2006-01-01

    Cumulus clouds can become tilted or elongated in the presence of wind shear. Nevertheless, most studies of the interaction of cumulus clouds and radiation have assumed these clouds to be isotropic. This paper describes an investigation of the effect of fair-weather cumulus cloud field anisotropy on domain-averaged solar fluxes and atmospheric heating rate profiles. A stochastic field generation algorithm was used to produce twenty three-dimensional liquid water content fields based on the statistical properties of cloud scenes from a large eddy simulation. Progressively greater degrees of x-z plane tilting and horizontal stretching were imposed on each of these scenes, so that an ensemble of scenes was produced for each level of distortion. The resulting scenes were used as input to a three-dimensional Monte Carlo radiative transfer model. Domain-average transmission, reflection, and absorption of broadband solar radiation were computed for each scene along with the average heating rate profile. Both tilt and horizontal stretching were found to significantly affect calculated fluxes, with the amount and sign of flux differences depending strongly on sun position relative to cloud distortion geometry. The mechanisms by which anisotropy interacts with solar fluxes were investigated by comparisons to independent pixel approximation and tilted independent pixel approximation computations for the same scenes. Cumulus anisotropy was found to most strongly impact solar radiative transfer by changing the effective cloud fraction, i.e., the cloud fraction when the field is projected on a surface perpendicular to the direction of the incident solar beam.

  5. Experimental Investigation of a Natural Circulation Solar Domestic Water Heater Performance under Standard Consumption Rate

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Taherian, H.; Ganji, D. D.

    2012-01-01

    This paper reports experimental studies on the performance of a natural circulation solar water heater considering the weather condition of a city in north of Iran. The tests are done on clear and partly cloudy days. The variations of storage tank temperature due to consumption from the tank, daily...... consumption influence on the solar water heater efficiency, and on the input temperature of the collector are studied and the delivered daily useful energy has been obtained. The results show that by withdrawing from storage tank, the system as well as its collector efficiency will increase. Considering...... the value of the coefficient FRUL and τα, which are obtained experimentally as 6.03 and 0.83 respectively, average. monthly total load that is covered by this solar water heating system is estimated....

  6. Effect of the new C-12(alpha, gamma)O-16 rate on the chemical evolution of the solar neighborhood

    International Nuclear Information System (INIS)

    Matteucci, F.

    1986-01-01

    New models of chemical evolution of the solar neighborhood have been computed by taking into account the effect of the revised rate of the C-12(alpha, gamma)O-16 reaction on the chemical yields from massive stars, together with the yields from low- and intermediate-mass stars which also include those from Type I supernova explosions (C-deflagration in white dwarfs). In particular, the evolution of C-12, N-14, O-16, Ne-20, Mg-24, Si-28, and Fe-56 has been followed in detail, and their predicted solar absolute abundances as well as their relative ratios, both in the sun and in metal-poor stars, have been compared with the observed ones. It is concluded that a model with the new yields combined with a Salpeter initial mass function, an upper cutoff mass of 100 solar masses (the mass beyond which stars are not contributing to the galactic enrichment), and an upper limiting mass for intermediate-mass stars of the order of 5 solar masses, is in best agreement with the observations. 34 references

  7. Sweat Rate Prediction Equations for Outdoor Exercise with Transient Solar Radiation

    Science.gov (United States)

    2012-01-01

    AD] 15 Interchangeable variables gSL W/m2 Global solar load Direct weather station data; pyranometer values 25 Direct measurement from weather station... pyranometer (to measure short-wave radiation fluxes) and pyrgeometer (to measure long-wave radiation fluxes). Normally, the value of the solar load...as described below. During field operations, Rsol (W/m2) can be calculated from 0.835 ·ERF. If Rsol (in W/m2) is known by direct pyranometer mea

  8. Balancing the daylighting and energy performance of solar screens in residential desert buildings: Examination of screen axial rotation and opening aspect ratio

    KAUST Repository

    Sabry, Hanan; Sherif, Ahmed; Gadelhak, Mahmoud; Aly, Mohamed

    2014-01-01

    Solar screens are typically used to control solar access into building spaces. They proved their usefulness in improving the daylighting and energy performance of buildings in the hot arid desert environments which are endowed with abundance

  9. Evaluation of the Effect of Rotation and Application Rate of Nitrogen on Yield, Yield Components and Nitrogen Efficiency Indexes in wheat

    Directory of Open Access Journals (Sweden)

    R Nasri

    2016-02-01

    seeding rate of 200 kg ha-1. Soil samples were collected after harvest of each crop from 0 to 30 cm and 31 to 60 cm soil depths using a soil auger. Wheat grain yield (according to 14% moisture obtained by harvesting the central area of 3 in 10 m in each plot. Yield components were determined from two randomly selected areas (2m2 within each plot. Plant samples collected at harvest were separated into grain and straw and oven-dried at 60˚C for 72hr. Biomass and grain sub samples analyzed for total N content using a micro-Kjeldahl digestion with sulfuric acid. The terminology of N efficiency parameters was considered according to Delogu et al, (11 and Lopez-Bellido & Lopez-Bellido, (22, Rahimizadeh et al. (30, Limon-Ortega et al. (20 methods. Results and Discussion The results showed that there were highly significant differences (P ≤ 0.01 in forage yield. There were also significant differences (P ≤ 0.05 in total dry weight, protein content and protein yield between treatments. Perko varieties produced higher fresh and dry matter yield with 69,586 (kg ha-1 and 7147 (kg ha-1, respectively compared to other varieties. Buko varieties showed greater protein percentage with 23.36 compared to the rest of the varieties. The highest and lowest grain yield, with 8345, and 4491 (kg ha-1 were obtained for Buko; wheat rotation and fallow, wheat rotation, respectively. The highest and lowest nitrogen uptake was obtained for Buko; wheat and clover, wheat rotation, respectively. The differences between the rotations were significant for various agronomic nitrogen efficiency. The rotation of oilseed radish and wheat showed greater nitrogen economic performance with 36.20 kg ha-1. By increasing nitrogen rate agronomic performance decreased with the exception in fallow- wheat. Physiological efficiency of nitrogen in fallow-wheat rotation was more than 39 (kg kg-1 of nitrogen. The maximum efficiency of nitrogen recovery was obtained for oilseed radish: wheat and Perko PVH; wheat

  10. Solar Radiation Disinfection of Drinking Water at Temperate Latitudes: Inactivation rates for an optimized reactor configuration

    Science.gov (United States)

    Solar radiation-driven inactivation of bacteria, virus and protozoan pathogen models was quantified in simulated drinking water at a temperate latitude (34°S). The water was seeded with Enterococcus faecalis, Clostridium sporogenes spores, and P22 bacteriophage, each at ca 1 x 10...

  11. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22.

    Science.gov (United States)

    Silva, H G; Lopes, I

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  12. Short-time variations of the solar neutrino luminosity (Fourier analysis of the argon-37 production rate data)

    International Nuclear Information System (INIS)

    Haubold, H.J.; Gerth, E.

    1985-01-01

    We continue the Fourier analysis of the argon-37 production rate for runs 18--80 observed in Davis' well known solar neutrino experiment. The method of Fourier analysis with the unequally-spaced data of Davis and associates is described and the discovered periods we compare with our recently published results for the analysis of runs 18--69 (Haubold and Gerth, 1983). The harmonic analysis of the data of runs 18--80 shows time variations of the solar neutrino flux with periods π = 8.33; 5.26; 2.13; 1.56; 0.83; 0.64; 0.54; and 0.50 years, respectively, which confirms our earlier computations

  13. Effect of sodium hyaluronate/carboxymethyl cellulose (Guardix-sol) on retear rate and postoperative stiffness in arthroscopic rotator cuff repair patients: A prospective cohort study.

    Science.gov (United States)

    Jeong, Jeung Yeol; Chung, Pill Ku; Yoo, Jae Chul

    2017-01-01

    Hyaluronate-based anti-adhesive agents are expected to enhance rotator cuff healing; however, their effect on the incidence and extent of postoperative complications such as stiffness and retears has not been investigated. From July 2012 to February 2013, 80 patients undergoing arthroscopic rotator cuff repair surgery were prospectively enrolled. Forty patients were assigned to the control group, while the other 40 were assigned to the injection group and received a Guardix-sol injection immediately after surgery. Passive range of motion, pain visual analog scale, and functional score were assessed at 8 weeks, 6 months, and 24 months postoperatively. Gliding motion between the deltoid muscle and the greater tuberosity of the proximal humerus was evaluated using ultrasonography at 2 and 8 weeks postoperatively, and tendon integrity was evaluated using magnetic resonance imaging at 6 months postoperatively. We found no significant difference between the groups regarding gliding motion at 2 weeks postoperatively. However, at 8 weeks, the incidence of poor gliding motion was 2.5% and 15% for the injected patients and control group, respectively, which was statistically significant. At 6 months after surgery, the retear rate between the two groups was not statistically significant. We found no statistically significant difference between the two groups regarding retear rate and clinical score throughout the follow-up period. We noted no complications related to the use of Guardix-sol. Patients who received the Guardix-sol injection showed improved gliding motion between the deltoid muscle and the greater tuberosity in the early postoperative period.

  14. Improved thermodynamics of the dense solar plasma and molecular-dynamics simulations of the nuclear-reaction rates

    Science.gov (United States)

    Mao, Dan

    The conditions in the solar interior are so extreme that it has so far been impossible to match them in a laboratory. However, for nearly 50 years solar oscillations have been precisely observed, and the wealth of their data has enabled us to study the interior of the Sun as if it were a laboratory. Helioseismology is the name of this branch of astrophysics. It allows a high- precision diagnostic of the thermodynamic quantities in the solar interior. High-quality thermodynamic quantities are crucial for successful solar modeling. If good solar models are desired, considerable theoretical effort is required. Good solar models, in turn, are fundamental tools for solar physics. The most prominent example of this link between solar physics and basic physics was the resolution of the solar neutrino problem in 2002. The equation of state is a key material property that describes the relation between pressure, density and temperature. If the equation of state is derived from a thermodynamic potential it will also determine all associated thermodynamic quantities. A second key material property is the nuclear-energy production rate, which plays a crucial role in the solar core. Both are important physical properties describing the structure of the Sun. Both derive from microphysical models. In the equation-of-state part, we have studied two models of the equation of state (EOS). One is the MHD EOS, which is widely used in solar models. In our research, we have incorporated new terms into the MHD EOS. These terms have been borrowed from the major competing formalism, the OPAL EOS. They were missing in the original MHD EOS. Not only do the upgrades bring MHD closer to the OPAL equation of state, which is well known for its better match with observations. Most importantly it will allow solar modelers to use the OPAL equation of state directly, without recourse to the OPAL tables distributed by the Lawrence Livermore National Laboratory. Since the OPAL code is not publicly

  15. Interaction Cross Sections and Survival Rates for Proposed Solar System Member Planet Nine

    Science.gov (United States)

    Li, Gongjie; Adams, Fred C.

    2016-05-01

    Motivated by the report of a possible new planetary member of the solar system, this work calculates cross sections for interactions between passing stars and this proposed Planet Nine. Evidence for the new planet is provided by the orbital alignment of Kuiper belt objects, and other solar system properties, which suggest a Neptune-mass object on an eccentric orbit with a semimajor axis {a}9 ≈ 400-1500 au. With such a wide orbit, Planet Nine has a large interaction cross section and is susceptible to disruption by passing stars. Using a large ensemble of numerical simulations (several million) and Monte Carlo sampling, we calculate the cross sections for different classes of orbit-altering events: (A) scattering the planet into its proposed orbit from a smaller orbit, (B) ejecting it from the solar system from its current orbit, (C) capturing the planet from another system, and (D) capturing a free-floating planet. Results are presented for a range of orbital elements with planetary mass {m}9 = 10 M ⊕. Removing Planet Nine from the solar system is the most likely outcome. Specifically, we obtain ejection cross sections {σ }{int} ˜ 5 × 106 au2 (5 × 104 au2) for environments corresponding to the birth cluster (field). With these cross sections, Planet Nine is likely to be ejected if the Sun resides within its birth cluster longer than Δt ≳ 100 Myr. The probability of ejecting Planet Nine due to passing field stars is ≲3% over the age of the Sun. Probabilities for producing the inferred Planet Nine orbit are low (≲5%).

  16. The effect and contribution of wind generated rotation on outlet temperature and heat gain of LS-2 parabolic trough solar collector

    Directory of Open Access Journals (Sweden)

    Sadaghiyani Omid Karimi

    2013-01-01

    Full Text Available The Monte Carlo ray tracing method is applied and coupled with finite volume numerical methods to study effect of rotation on outlet temperature and heat gain of LS-2 parabolic trough concentrator (PTC. Based on effect of sunshape, curve of mirror and use of MCRT, heat flux distribution around of inner wall of evacuated tube is calculated. After calculation of heat flux, the geometry of LS-2 Luz collector is created and finite volume method is applied to simulate. The obtained results are compared with Dudley et al test results for irrotational cases to validate these numerical solving models. Consider that, for rotational models ,the solving method separately with K.S. Ball's results. In this work, according to the structure of mentioned collector, we use plug as a flow restriction. In the rotational case studies, the inner wall rotates with different angular speeds. We compare results of rotational collector with irrotational. Also for these two main states, the location of plug changed then outlet temperature and heat gain of collector are studied. The results show that rotation have positive role on heat transfer processing and the rotational plug in bottom half of tube have better effectual than upper half of tube. Also the contribution of rotation is calculated in the all of case studies. Working fluid of these study is one of the oil derivatives namely Syltherm-800. The power of wind can be used to rotate tube of collector.

  17. Rotating flow

    CERN Document Server

    Childs, Peter R N

    2010-01-01

    Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

  18. 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.

  19. On the Solar oblateness

    International Nuclear Information System (INIS)

    Kislik, M.D.

    1983-01-01

    Limits for the magnitude of Solar oblateness under the assumption that the Sun is rotating as a rigid body with the velocity of sideric rotation of the equator points have been determined. It is demonstrated that for the present there is no necessity to take into accoUnt Solar oblateness when making the interior planets movement theories

  20. Chaotic Zones around Rotating Small Bodies

    Energy Technology Data Exchange (ETDEWEB)

    Lages, José; Shevchenko, Ivan I. [Institut UTINAM, Observatoire des Sciences de l’Univers THETA, CNRS, Université de Franche-Comté, Besançon F-25030 (France); Shepelyansky, Dima L., E-mail: jose.lages@utinam.cnrs.fr [Laboratoire de Physique Théorique du CNRS, IRSAMC, Université de Toulouse, UPS, Toulouse F-31062 (France)

    2017-06-01

    Small bodies of the solar system, like asteroids, trans-Neptunian objects, cometary nuclei, and planetary satellites, with diameters smaller than 1000 km usually have irregular shapes, often resembling dumb-bells or contact binaries. The spinning of such a gravitating dumb-bell creates around it a zone of chaotic orbits. We determine its extent analytically and numerically. We find that the chaotic zone swells significantly if the rotation rate is decreased; in particular, the zone swells more than twice if the rotation rate is decreased 10 times with respect to the “centrifugal breakup” threshold. We illustrate the properties of the chaotic orbital zones in examples of the global orbital dynamics about asteroid 243 Ida (which has a moon, Dactyl, orbiting near the edge of the chaotic zone) and asteroid 25143 Itokawa.

  1. Time-dependent Occurrence Rate of Electromagnetic Cyclotron Waves in the Solar Wind: Evidence for the Effect of Alpha Particles?

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, G. Q.; Feng, H. Q. [Institute of Space Physics, Luoyang Normal University, Luoyang (China); Wu, D. J. [Purple Mountain Observatory, CAS, Nanjing (China); Chu, Y. H. [Institute of Space Science, National Central University, Chungli, Taiwan (China); Huang, J. [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing (China)

    2017-09-20

    Previous studies revealed that electromagnetic cyclotron waves (ECWs) near the proton cyclotron frequency exist widely in the solar wind, and the majority of ECWs are left-handed (LH) polarized waves. Using the magnetic field data from the STEREO mission, this Letter carries out a survey of ECWs over a long period of 7 years and calculates the occurrence rates of ECWs with different polarization senses. Results show that the occurrence rate is nearly a constant for the ECWs with right-handed polarization, but it varies significantly for the ECWs with LH polarization. Further investigation of plasma conditions reveals that the LH ECWs take place preferentially in a plasma characterized by higher temperature, lower density, and larger velocity. Some considerable correlations between the occurrence rate of LH ECWs and the properties of ambient plasmas are discussed. The present research may provide evidence for the effect of alpha particles on the generation of ECWs.

  2. CdS films deposited by chemical bath under rotation

    International Nuclear Information System (INIS)

    Oliva-Aviles, A.I.; Patino, R.; Oliva, A.I.

    2010-01-01

    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 2 , KOH, NH 4 NO 3 and CS(NH 2 ) 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.

  3. 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.

  4. Balance of longwave radiation employing the rate of solar radiation for Santa Maria, Rio Grande do Sul, Brazil1

    Directory of Open Access Journals (Sweden)

    Evandro Zanini Righi

    Full Text Available New coefficients were determined for the weighting term for cloudiness in the Brunt-Penman equation using the rate of solar radiation (RK in place of the rate of sunshine duration (n/N. The coefficients in the Brutsaert method proposed for daytime in southern Brazil were also tested and adjusted, and the method was selected which gave the more accurate daily results in relation to the original Brunt-Penman equation, for Santa Maria in the state of Rio Grande do Sul, Brazil (RS. Meteorological data covering 2,472 days obtained from the automatic and conventional weather stations in Santa Maria were used. The coefficients were adjusted by linear and nonlinear regression methods depending on the model, using 2/3 of the data. The adjusted equations were tested with the remaining 1/3 of the data. The Brunt-Penman equation modified by the term for cloudiness weighted both for solar radiation incident on the surface with no cloudiness (RK,R and for solar radiation incident at the top of the atmosphere (RK,K, were those that resulted in the best statistical indices relative to the original Brunt-Penman equation. In those equations the boundary conditions, 0.3 ≥ RK,R ≥ 1 or RK,K ≤ 0.22, were imposed. Although having similar statistical indices, a sensitivity analysis showed that the Brutsaert equation and other weightings for cloudiness resulted in larger deviations when compared to the original Brunt-Penman equation, in addition to having greater complexity for practical application.

  5. The effect of temperature and heating rate on char properties obtained from solar pyrolysis of beech wood.

    Science.gov (United States)

    Zeng, Kuo; Minh, Doan Pham; Gauthier, Daniel; Weiss-Hortala, Elsa; Nzihou, Ange; Flamant, Gilles

    2015-04-01

    Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000°C, with heating rates from 5 to 450°C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50°C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200°C then reduced significantly at 2000°C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450°C/s when final temperature was no lower than 1200°C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Low-Temperature, Chemically Grown Titanium Oxide Thin Films with a High Hole Tunneling Rate for Si Solar Cells

    Directory of Open Access Journals (Sweden)

    Yu-Tsu Lee

    2016-05-01

    Full Text Available In this paper, we propose a chemically grown titanium oxide (TiO2 on Si to form a heterojunction for photovoltaic devices. The chemically grown TiO2 does not block hole transport. Ultraviolet photoemission spectroscopy was used to study the band alignment. A substantial band offset at the TiO2/Si interface was observed. X-ray photoemission spectroscopy (XPS revealed that the chemically grown TiO2 is oxygen-deficient and contains numerous gap states. A multiple-trap-assisted tunneling (TAT model was used to explain the high hole injection rate. According to this model, the tunneling rate can be 105 orders of magnitude higher for holes passing through TiO2 than for flow through SiO2. With 24-nm-thick TiO2, a Si solar cell achieves a 33.2 mA/cm2 photocurrent on a planar substrate, with a 9.4% power conversion efficiency. Plan-view scanning electron microscopy images indicate that a moth-eye-like structure formed during TiO2 deposition. This structure enables light harvesting for a high photocurrent. The high photocurrent and ease of production of chemically grown TiO2 imply that it is a suitable candidate for future low-cost, high-efficiency solar cell applications.

  7. Contributions of solar-wind induced potential sputtering to the lunar surface erosion rate and it's exosphere

    Science.gov (United States)

    Alnussirat, S. T.; Barghouty, A. F.; Edmunson, J. E.; Sabra, M. S.; Rickman, D. L.

    2018-04-01

    Sputtering of lunar regolith by solar-wind protons and heavy ions with kinetic energies of about 1 keV/amu is an important erosive process that affects the lunar surface and exosphere. It plays an important role in changing the chemical composition and thickness of the surface layer, and in introducing material into the exosphere. Kinetic sputtering is well modeled and understood, but understanding of mechanisms of potential sputtering has lagged behind. In this study we differentiate the contributions of potential sputtering from the standard (kinetic) sputtering in changing the chemical composition and erosion rate of the lunar surface. Also we study the contribution of potential sputtering in developing the lunar exosphere. Our results show that potential sputtering enhances the total characteristic sputtering erosion rate by about 44%, and reduces sputtering time scales by the same amount. Potential sputtering also introduces more material into the lunar exosphere.

  8. Solar cell of 6.3% efficiency employing high deposition rate (8 nm/s) microcrystalline silicon photovoltaic layer

    Energy Technology Data Exchange (ETDEWEB)

    Sobajima, Yasushi; Nishino, Mitsutoshi; Fukumori, Taiga; Kurihara, Masanori; Higuchi, Takuya; Nakano, Shinya; Toyama, Toshihiko; Okamoto, Hiroaki [Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Toyonaka, Machikaneyama-cho 1-3, Osaka 560-8531 (Japan)

    2009-06-15

    Microcrystalline silicon ({mu}c-Si) films deposited at high growth rates up to 8.1 nm/s prepared by very-high-frequency-plasma-enhanced chemical vapor deposition (VHF-PECVD) at 18-24 Torr have been investigated. The relation between the deposition rates and input power revealed the depletion of silane. Under high-pressure deposition (HPD) conditions, the structural properties were improved. Furthermore, applying {mu}c-Si to n-i-p solar cells, short-circuit current density (J{sub SC}) was increased in accordance with the improvement of microstructure of i-layer. As a result, a conversion efficiency of 6.30% has been achieved employing the i-layer deposited at 8.1 nm/s under the HPD conditions. (author)

  9. Global rotation

    International Nuclear Information System (INIS)

    Rosquist, K.

    1980-01-01

    Global rotation in cosmological models is defined on an observational basis. A theorem is proved saying that, for rigid motion, the global rotation is equal to the ordinary local vorticity. The global rotation is calculated in the space-time homogeneous class III models, with Godel's model as a special case. It is shown that, with the exception of Godel's model, the rotation in these models becomes infinite for finite affine parameter values. In some directions the rotation changes sign and becomes infinite in a direction opposite to the local vorticity. The points of infinite rotation are identified as conjugate points along the null geodesics. The physical interpretation of the infinite rotation is discussed, and a comparison with the behaviour of the area distance at conjugate points is given. (author)

  10. Perturbation of longitudinal relaxation rate in rotating frame (PLRF) analysis for quantification of chemical exchange saturation transfer signal in a transient state.

    Science.gov (United States)

    Wang, Yi; Zhang, Yaoyu; Zhao, Xuna; Wu, Bing; Gao, Jia-Hong

    2017-11-01

    To develop a novel analytical method for quantification of chemical exchange saturation transfer (CEST) in the transient state. The proposed method aims to reduce the effects of non-chemical-exchange (non-CE) parameters on the CEST signal, emphasizing the effect of chemical exchange. The difference in the longitudinal relaxation rate in the rotating frame ( ΔR1ρ) was calculated based on perturbation of the Z-value by R1ρ, and a saturation-pulse-amplitude-compensated exchange-dependent relaxation rate (SPACER) was determined with a high-exchange-rate approximation. In both phantom and human subject experiments, MTRasym (representative of the traditional CEST index), ΔR1ρ, and SPACER were measured, evaluated, and compared by altering the non-CE parameters in a transient-state continuous-wave CEST sequence. In line with the theoretical expectation, our experimental data demonstrate that the effects of the non-CE parameters can be more effectively reduced using the proposed indices (  ΔR1ρ and SPACER) than using the traditional CEST index ( MTRasym). The proposed method allows for the chemical exchange weight to be better emphasized in the transient-state CEST signal, which is beneficial, in practice, for quantifying the CEST signal. Magn Reson Med 78:1711-1723, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  11. Lunar Rotation, Orientation and Science

    Science.gov (United States)

    Williams, J. G.; Ratcliff, J. T.; Boggs, D. H.

    2004-12-01

    The Moon is the most familiar example of the many satellites that exhibit synchronous rotation. For the Moon there is Lunar Laser Ranging measurements of tides and three-dimensional rotation variations plus supporting theoretical understanding of both effects. Compared to uniform rotation and precession the lunar rotational variations are up to 1 km, while tidal variations are about 0.1 m. Analysis of the lunar variations in pole direction and rotation about the pole gives moment of inertia differences, third-degree gravity harmonics, tidal Love number k2, tidal dissipation Q vs. frequency, dissipation at the fluid-core/solid-mantle boundary, and emerging evidence for an oblate boundary. The last two indicate a fluid core, but a solid inner core is not ruled out. Four retroreflectors provide very accurate positions on the Moon. The experience with the Moon is a starting point for exploring the tides, rotation and orientation of the other synchronous bodies of the solar system.

  12. ULY JUP GRB SOLAR X-RAY/COSMIC GAMMA-RAY RAW COUNT RATE

    Data.gov (United States)

    National Aeronautics and Space Administration — The archived data consist of count rates from the sum of two hemispherical detectors covering 4 pi steradians and operating continuously. The detectors are 3 mm...

  13. Impact of Alternative Rate Structures on Distributed Solar Customer Electricity Bills

    Energy Technology Data Exchange (ETDEWEB)

    McLaren, Joyce A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-03-02

    Electric utilities are increasingly proposing changes to residential rate structures, in order to address concerns about their inability to recover fixed system costs from customers with grid connected distributed generation. The most common proposals have been to increase fixed charges, set minimum bills or instigate residential demand charges. This presentation provides results of an analysis to explore how these rate design alternatives impact electricity bills for PV and non-PV customers.

  14. Decrease of back recombination rate in CdS quantum dots sensitized solar cells using reduced graphene oxide

    International Nuclear Information System (INIS)

    Badawi Ali

    2015-01-01

    The photovoltaic performance of CdS quantum dots sensitized solar cells (QDSSCs) using the 0.2 wt% of reduced graphene oxide and TiO 2 nanoparticles (RGO+TiO 2 nanocomposite) photoanode is investigated. CdS QDs are adsorbed onto RGO+TiO 2 nanocomposite films by the successive ionic layer adsorption and reaction (SILAR) technique for several cycles. The current density–voltage (J–V) characteristic curves of the assembled QDSSCs are measured at AM1.5 simulated sunlight. The optimal photovoltaic performance for CdS QDSSC was achieved for six SILAR cycles. Solar cells based on the RGO+TiO 2 nanocomposite photoanode achieve a 33% increase in conversion efficiency (η) compared with those based on plain TiO 2 nanoparticle (NP) photoanodes. The electron back recombination rates decrease significantly for CdS QDSSCs based on RGO+TiO 2 nanocomposite photoanodes. The lifetime constant (τ) for CdS QDSSC based on the RGO+TiO 2 nanocomposite photoanode is at least one order of magnitude larger than that based on the bare TiO 2 NPs photoanode. (paper)

  15. Solar ultraviolet-B radiation affects seedling emergence, DNA integrity, plant morphology, growth rate, and attractiveness to herbivore insects in Datura ferox

    International Nuclear Information System (INIS)

    Ballare, C.L.; Scopel, A.L.; Stapleton, A.E.

    1996-01-01

    To study functional relationships between the effects of solar ultraviolet-B radiation (UV0B) on different aspects of the physiology of a wild plant, we carried out exclusion experiments in the field with the summer annual Datura ferrox L. Solar UV-B incident over Buenos Aires reduced daytime seedling emergence, inhibited stem elongation and leaf expansion, and tended to reduce biomass accumulation during early growth. However, UV-B had no effect on calculated net assimilation rate. Using a monoclonal antibody specific to the cyclobutane-pyrimidine dimer (CPD), we found that plants receiving full sunlight had more CPDs per unit of DNA than plants shielded from solar UV-B, but the positive correlation between UV-B and CPD burden tended to level off at high (near solar) UV-B levels. At our field site, Datura plants were consumed by leaf beetles (Coleoptera), and the proportion of plants attacked by insects declined with the amount of UV-B received during growth. Field experiments showed that plant exposure to solar UV-B reduced the likelihood of leaf beetle attack by one-half. Our results highlight the complexities associated with scaling plant responses to solar UV-B, because they show: (a) a lack of correspondence between UV-B effects on net assimilation rate and whole-plant growth rate, (b) nonlinear UV-B dose-response curves, and (c) UV-B effects of plant attractiveness to natural herbivores. 56 refs., 7 figs

  16. Recombination rates in heterojunction silicon solar cells analyzed by impedance spectroscopy at forward bias and under illumination

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Sero, Ivan; Luo, Yan; Garcia-Belmonte, Germa; Bisquert, Juan [Departament de Fisica, Universitat Jaume I, E-12071 Castello (Spain); Munoz, Delfina; Voz, Cristobal; Puigdollers, Joaquim; Alcubilla, Ramon [Departament d' Enginyeria Electronica, Universitat Politecnica de Catalunya, E-08034 Barcelona (Spain)

    2008-04-15

    Impedance spectroscopy (at forward bias and under illumination) of solar cells comprised thin hydrogenated amorphous silicon (a-Si:H) films deposited on crystalline silicon (c-Si) wafers was analyzed in terms of ac equivalent circuits. Shockley-Read-Hall recombination at states on the device interfaces governs the cell dynamic response. Recombination process was modeled by means of simple RC circuits which allow to determine the capture rate of electrons and holes. Carrier lifetime is found to be stated by the electron capture time {tau}{sub SRH}{approx}{tau}{sub n}, and it results in the range of 300 {mu}s. The Al-annealed back contact was regarded as the dominating recombination interface. (author)

  17. Electrochemical reaction rates in a dye-sensitised solar cell - the iodide/tri-iodide redox system

    DEFF Research Database (Denmark)

    Bay, L.; West, K.; Winther-Jensen, B.

    2006-01-01

    The electrochemical reaction rate of the redox couple iodide/tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide....../tri-iodide couple should be fast at the counter electrode, i.e. this electrode must have a high catalytic activity towards the redox couple, and the same reaction must be slow on the photo electrode. The catalytic activity is investigated for platinum, poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy......), and polyaniline (PANI)-all deposited onto fluorine-doped tin oxide (FTO) glass. Both Pt and PEDOT are found to have sufficiently high catalytic activities for practical use as counter electrodes in DSSC. The reaction resistance on FTO and anatase confirmed the beneficial effect of a compact anatase layer on top...

  18. Comparative Study for Evaluation of Mass Flow Rate for Simple Solar Still and Active with Heat Pump

    OpenAIRE

    Hidouri Khaoula; Benhmidene Ali; Chaouachi Bechir; Ravishankar Sathyamurthy

    2017-01-01

    In isolated and arid areas, especially in the almost Maghreb regions, the abundant solar radiation intensity along the year and the available brackish water resources are the two favorable conditions for using solar desalination technology to produce fresh water. The present study is based on the use of three groups of correlation, for evaluating mass transfer. Theoretical results are compared with those obtained experimentally for a Simple Solar Distiller (SSD) and a Simple Solar Distiller H...

  19. Improving the API dissolution rate during pharmaceutical hot-melt extrusion I: Effect of the API particle size, and the co-rotating, twin-screw extruder screw configuration on the API dissolution rate.

    Science.gov (United States)

    Li, Meng; Gogos, Costas G; Ioannidis, Nicolas

    2015-01-15

    The dissolution rate of the active pharmaceutical ingredients in pharmaceutical hot-melt extrusion is the most critical elementary step during the extrusion of amorphous solid solutions - total dissolution has to be achieved within the short residence time in the extruder. Dissolution and dissolution rates are affected by process, material and equipment variables. In this work, we examine the effect of one of the material variables and one of the equipment variables, namely, the API particle size and extruder screw configuration on the API dissolution rate, in a co-rotating, twin-screw extruder. By rapidly removing the extruder screws from the barrel after achieving a steady state, we collected samples along the length of the extruder screws that were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC) to determine the amount of undissolved API. Analyses of samples indicate that reduction of particle size of the API and appropriate selection of screw design can markedly improve the dissolution rate of the API during extrusion. In addition, angle of repose measurements and light microscopy images show that the reduction of particle size of the API can improve the flowability of the physical mixture feed and the adhesiveness between its components, respectively, through dry coating of the polymer particles by the API particles. Copyright © 2014. Published by Elsevier B.V.

  20. Units of rotational information

    Science.gov (United States)

    Yang, Yuxiang; Chiribella, Giulio; Hu, Qinheping

    2017-12-01

    Entanglement in angular momentum degrees of freedom is a precious resource for quantum metrology and control. Here we study the conversions of this resource, focusing on Bell pairs of spin-J particles, where one particle is used to probe unknown rotations and the other particle is used as reference. When a large number of pairs are given, we show that every rotated spin-J Bell state can be reversibly converted into an equivalent number of rotated spin one-half Bell states, at a rate determined by the quantum Fisher information. This result provides the foundation for the definition of an elementary unit of information about rotations in space, which we call the Cartesian refbit. In the finite copy scenario, we design machines that approximately break down Bell states of higher spins into Cartesian refbits, as well as machines that approximately implement the inverse process. In addition, we establish a quantitative link between the conversion of Bell states and the simulation of unitary gates, showing that the fidelity of probabilistic state conversion provides upper and lower bounds on the fidelity of deterministic gate simulation. The result holds not only for rotation gates, but also to all sets of gates that form finite-dimensional representations of compact groups. For rotation gates, we show how rotations on a system of given spin can simulate rotations on a system of different spin.

  1. Predicting Precession Rates from Secular Dynamics for Extra-solar Multi-planet Systems

    Science.gov (United States)

    Van Laerhoven, Christa

    2015-12-01

    Considering the secular dynamics of multi-planet systems provides substantial insight into the interactions between planets in those systems. Secular interactions are those that don't involve knowing where a planet is along its orbit, and they dominate when planets are not involved in mean motion resonances. These interactions exchange angular momentum among the planets, evolving their eccentricities and inclinations. To second order in the planets' eccentricities and inclinations, the eccentricity and inclination perturbations are decoupled. Given the right variable choice, the relevant differential equations are linear and thus the eccentricity and inclination behaviors can be described as a sum of eigenmodes. Since the underlying structure of the secular eigenmodes can be calculated using only the planets' masses and semi-major axes, one can elucidate the eccentricity and inclination behavior of planets in exoplanet systems even without knowing the planets' current eccentricities and inclinations. I have calculated both the eccentricity and inclination secular eigenmodes for the population of known multi-planet systems whose planets have well determined masses and periods and have used this to predict what range of pericenter precession (and nodal regression) rates the planets may have. One might have assumed that in any given system the planets with shorter periods would have faster precession rates, but I show that this is not necessarily the case. Planets that are 'loners' have narrow ranges of possible precession rates, while planets that are 'groupies' can have a wider range of possible precession rates. Several planets are expected to undergo significant precession on few-year timescales and many planets (though not the majority of planets) will undergo significant precession on decade timescales.

  2. Rotating Wavepackets

    Science.gov (United States)

    Lekner, John

    2008-01-01

    Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

  3. Rotating dryer

    International Nuclear Information System (INIS)

    Noe, C.

    1984-01-01

    Products to dry are introduced inside a rotating tube placed in an oven, the cross section of the tube is an arc of spiral. During clockwise rotation of the tube products are maintained inside and mixed, during anticlockwise products are removed. Application is made to drying of radioactive wastes [fr

  4. EFFECTS OF ROTATIONALLY INDUCED MIXING IN COMPACT BINARY SYSTEMS WITH LOW-MASS SECONDARIES AND IN SINGLE SOLAR-TYPE STARS

    International Nuclear Information System (INIS)

    Chatzopoulos, E.; Robinson, Edward L.; Wheeler, J. Craig

    2012-01-01

    Many population synthesis and stellar evolution studies have addressed the evolution of close binary systems in which the primary is a compact remnant and the secondary is filling its Roche lobe, thus triggering mass transfer. Although tidal locking is expected in such systems, most studies have neglected the rotationally induced mixing that may occur. Here we study the possible effects of mixing in mass-losing stars for a range of secondary star masses and metallicities. We find that tidal locking can induce rotational mixing prior to contact and thus affect the evolution of the secondary star if the effects of the Spruit-Tayler dynamo are included both for angular momentum and chemical transport. Once contact is made, the effect of mass transfer tends to be more rapid than the evolutionary timescale, so the effects of mixing are no longer directly important, but the mass-transfer strips matter to inner layers that may have been affected by the mixing. These effects are enhanced for secondaries of 1-1.2 M ☉ and for lower metallicities. We discuss the possible implications for the paucity of carbon in the secondaries of the cataclysmic variable SS Cyg and the black hole candidate XTE J1118+480 and for the progenitor evolution of Type Ia supernovae. We also address the issue of the origin of blue straggler stars in globular and open clusters. We find that for models that include rotation consistent with that observed for some blue straggler stars, evolution is chemically homogeneous. This leads to tracks in the H-R diagram that are brighter and bluer than the non-rotating main-sequence turn-off point. Rotational mixing could thus be one of the factors that contribute to the formation of blue stragglers.

  5. MAGNETIC ROSSBY WAVES IN THE SOLAR TACHOCLINE AND RIEGER-TYPE PERIODICITIES

    International Nuclear Information System (INIS)

    Zaqarashvili, Teimuraz V.; Carbonell, Marc; Oliver, Ramon; Ballester, Jose Luis

    2010-01-01

    Apart from the eleven-year solar cycle, another periodicity around 155-160 days was discovered during solar cycle 21 in high-energy solar flares, and its presence in sunspot areas and strong magnetic flux has been also reported. This periodicity has an elusive and enigmatic character, since it usually appears only near the maxima of solar cycles, and seems to be related with a periodic emergence of strong magnetic flux at the solar surface. Therefore, it is probably connected with the tachocline, a thin layer located near the base of the solar convection zone, where a strong dynamo magnetic field is stored. We study the dynamics of Rossby waves in the tachocline in the presence of a toroidal magnetic field and latitudinal differential rotation. Our analysis shows that the magnetic Rossby waves are generally unstable and that the growth rates are sensitive to the magnetic field strength and to the latitudinal differential rotation parameters. Variation of the differential rotation and the magnetic field strength throughout the solar cycle enhance the growth rate of a particular harmonic in the upper part of the tachocline around the maximum of the solar cycle. This harmonic is symmetric with respect to the equator and has a period of 155-160 days. A rapid increase of the wave amplitude could give rise to a magnetic flux emergence leading to observed periodicities in solar activity indicators related to magnetic flux.

  6. Sonographic evaluation of the fetal spine position and success rate of manual rotation of the fetus in occiput posterior position: A randomized controlled trial.

    Science.gov (United States)

    Masturzo, Bianca; Farina, Antonio; Attamante, Lorenza; Piazzese, Annalisa; Rolfo, Alessandro; Gaglioti, Pietro; Todros, Tullia

    2017-10-01

    To evaluate whether sonographic (US) diagnosis of the fetal spine position could increase the success rate of manual rotation of the fetal occiput (MRFO) in second-stage arrest in persistent occiput posterior position (OPP). In this randomized controlled parallel single-center trial, 58 nulliparous in second-stage arrest of labor with fetus in cephalic presentation and OPP diagnosed by US were randomly assigned to group A where the fetal spine position was not known by the operator or to group B where the operator knew it. The main outcome was the success of MRFO in the two groups. Secondary outcomes were perineal injuries, blood loss, duration of expulsive period, and neonatal APGAR at 5 minutes. A priori knowledge of the spine position improves the success of the MRFO (41.4% group A versus 82.8% group B, p value < 0.001), the percentage of spontaneous deliveries (27.6% group A versus 69% group B, p value = 0.01), and maternal outcome (intact perineum and blood loss). No differences were detected on the neonatal side. MRFO is a safe and useful procedure that should be performed in second-stage arrest in OPP. A better performance was observed when supported by the US knowledge of the spine position. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:472-476, 2017. © 2017 Wiley Periodicals, Inc.

  7. 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.

  8. Comparative Photoelectrochemical Study of PEC Solar Cell Fabricated with n-TiO2 Photo-electrodes at Different Temperatures and under Different Oxygen Flow Rates

    International Nuclear Information System (INIS)

    Mishra, P.R.; Srivastava, O.N.; Shukla, P.K.

    2006-01-01

    Photoelectrochemical splitting of water induced by solar energy for hydrogen production has been studied in the present investigation. PEC solar cell was fabricated with n-TiO 2 photo-electrodes synthesized at different oxidation temperatures e.g. 700 C, 750 C, 800 C and 850 C under oxygen flow rate 200 ml/min, 350 ml/min and 500 ml/min. The optimum oxygen flow rate for all the temperatures was found to be 350 ml/min. This is therefore kept invariant for synthesis of electrodes at different temperatures. The photo-electrochemical characterization of the PEC cell was done in the three-electrode configuration, i.e Ti/n-TiO 2 /1M-NaOH/Pt. It has been observed that the optimum values of the PEC solar cell parameters are exhibited by the solar cell employing the photo-electrodes prepared at ∼7500 C. The XRD and SEM explorations revealed that the TiO 2 prepared at ∼7500 C is in the nano-metric range (∼100-150 nm). The TiO 2 films formed at this temperature has been found to exhibit optimum PEC solar cell parameters. The PEC parameters, like photocurrent density, photo-conversion efficiency and hydrogen production rate, with this photo-electrode correspond to 0.93 mA/cm 2 , 0.472% and 4.00 l/hm 2 respectively. (authors)

  9. Determination of the Three-Dimensional Rate of Cancer Cell Rotation in an Optically-Induced Electrokinetics Chip Using an Optical Flow Algorithm

    Directory of Open Access Journals (Sweden)

    Yuliang Zhao

    2018-03-01

    Full Text Available Our group has reported that Melan-A cells and lymphocytes undergo self-rotation in a homogeneous AC electric field, and found that the rotation velocity of these cells is a key indicator to characterize their physical properties. However, the determination of the rotation properties of a cell by human eyes is both gruesome and time consuming, and not always accurate. In this paper, a method is presented to more accurately determine the 3D cell rotation velocity and axis from a 2D image sequence captured by a single camera. Using the optical flow method, we obtained the 2D motion field data from the image sequence and back-project it onto a 3D sphere model, and then the rotation axis and velocity of the cell were calculated. After testing the algorithm on animated image sequences, experiments were also performed on image sequences of real rotating cells. All of these results indicate that this method is accurate, practical, and useful. Furthermore, the method presented there can also be used to determine the 3D rotation velocity of other types of spherical objects that are commonly used in microfluidic applications, such as beads and microparticles.

  10. A cone-like enhancement of polar solar corona plasma and its influence on heliospheric particles

    Science.gov (United States)

    Grzedzielski, Stan; Sokół, Justyna M.

    2017-04-01

    We will present results of the study of the properties of the solar wind plasma due to rotation of the polar solar corona. We focus in our study on the solar minimum conditions, when the polar coronal holes are well formed and the magnetic field in the solar polar corona exhibit almost regular "ray-like" structure. The solar rotation twists the magnetic field lines of the expanding fast polar solar wind and the resulting toroidal component of the field induces a force directed towards the rotation axis. This phenomenon is tantamount to a (weak) zeta pinch, known also in other astrophysical contexts (e.g. like in AGN jets). The pinch compresses the polar solar corona plasma and forms a cone-like enhancement of the solar wind density aligned with the rotation axis in the spherically symmetric case. The effect is likely very dynamic due to fast changing conditions in the solar corona, however in the study presented here, we assume a time independent description to get an order-of-magnitude estimate. The weak pinch is treated as a first-order perturbation to the zeroth-order radial flow. Following the assumptions based on the available knowledge about the plasma properties in the polar solar corona we estimated the most typical density enhancements. The cone like structure may extend as far from the Sun as tens of AU and thus will influence the heliospheric particles inside the heliosphere. An increase of the solar wind density in the polar region may be related with a decrease of the solar wind speed. Such changes of the solar wind plasma at high latitudes may modify the charge-exchange and electron impact ionization rates of heliospheric particles in interplanetary space. We will present their influence on the interstellar neutral gas and energetic neutral atoms observed by IBEX.

  11. An experimental study of the mass flow rates effect on flat-plate solar water heater performance using Al2O3/water nanofluid

    Directory of Open Access Journals (Sweden)

    Prakasam Michael Joseph Stalin

    2017-01-01

    Full Text Available In the present work, flat plate solar water heating system has been designed and fabricated accommodating 2 m2 area of solar collector and 0.12 m2 surface area of the heat exchanger using Al2O3/water nanofluid as the working fluid in order to evaluate the performance efficiency in the forced circulation mode. The instantaneous efficiency of solar collector is calculated by taking lower volume fraction of 0.01% with average particle size of 25 nm with and without Triton X-100 surfactant and varying the flow rate from 1 L per minute to 3 L per minute, as per ASHRAE standard. The experimental results show that utilizing Al2O3/water nanofluid with mass flow rate at 2 L per minute increases the collector efficiency by 14.3% when compared to distilled water as the working medium.

  12. HIGH-RESOLUTION CALCULATION OF THE SOLAR GLOBAL CONVECTION WITH THE REDUCED SPEED OF SOUND TECHNIQUE. II. NEAR SURFACE SHEAR LAYER WITH THE ROTATION

    Energy Technology Data Exchange (ETDEWEB)

    Hotta, H.; Rempel, M. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Yokoyama, T., E-mail: hotta@ucar.edu [Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2015-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R {sub ☉} and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R {sub ☉}. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 results from rotationally aligned convection cells ({sup b}anana cells{sup )}. The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

  13. THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF WARM AND HOT JUPITERS: EFFECTS OF ORBITAL DISTANCE, ROTATION PERIOD, AND NONSYNCHRONOUS ROTATION

    Energy Technology Data Exchange (ETDEWEB)

    Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States); Lewis, Nikole K. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Fortney, Jonathan J., E-mail: showman@lpl.arizona.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2015-03-10

    Efforts to characterize extrasolar giant planet (EGP) atmospheres have so far emphasized planets within 0.05 AU of their stars. Despite this focus, known EGPs populate a continuum of orbital separations from canonical hot Jupiter values (0.03–0.05 AU) out to 1 AU and beyond. Unlike typical hot Jupiters, these more distant EGPs will not generally be synchronously rotating. In anticipation of observations of this population, we here present three-dimensional atmospheric circulation models exploring the dynamics that emerge over a broad range of rotation rates and incident stellar fluxes appropriate for warm and hot Jupiters. We find that the circulation resides in one of two basic regimes. On typical hot Jupiters, the strong day–night heating contrast leads to a broad, fast superrotating (eastward) equatorial jet and large day–night temperature differences. At faster rotation rates and lower incident fluxes, however, the day–night heating gradient becomes less important, and baroclinic instabilities emerge as a dominant player, leading to eastward jets in the midlatitudes, minimal temperature variations in longitude, and, often, weak winds at the equator. Our most rapidly rotating and least irradiated models exhibit similarities to Jupiter and Saturn, illuminating the dynamical continuum between hot Jupiters and the weakly irradiated giant planets of our own solar system. We present infrared (IR) light curves and spectra of these models, which depend significantly on incident flux and rotation rate. This provides a way to identify the regime transition in future observations. In some cases, IR light curves can provide constraints on the rotation rate of nonsynchronously rotating planets.

  14. THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF WARM AND HOT JUPITERS: EFFECTS OF ORBITAL DISTANCE, ROTATION PERIOD, AND NONSYNCHRONOUS ROTATION

    International Nuclear Information System (INIS)

    Showman, Adam P.; Lewis, Nikole K.; Fortney, Jonathan J.

    2015-01-01

    Efforts to characterize extrasolar giant planet (EGP) atmospheres have so far emphasized planets within 0.05 AU of their stars. Despite this focus, known EGPs populate a continuum of orbital separations from canonical hot Jupiter values (0.03–0.05 AU) out to 1 AU and beyond. Unlike typical hot Jupiters, these more distant EGPs will not generally be synchronously rotating. In anticipation of observations of this population, we here present three-dimensional atmospheric circulation models exploring the dynamics that emerge over a broad range of rotation rates and incident stellar fluxes appropriate for warm and hot Jupiters. We find that the circulation resides in one of two basic regimes. On typical hot Jupiters, the strong day–night heating contrast leads to a broad, fast superrotating (eastward) equatorial jet and large day–night temperature differences. At faster rotation rates and lower incident fluxes, however, the day–night heating gradient becomes less important, and baroclinic instabilities emerge as a dominant player, leading to eastward jets in the midlatitudes, minimal temperature variations in longitude, and, often, weak winds at the equator. Our most rapidly rotating and least irradiated models exhibit similarities to Jupiter and Saturn, illuminating the dynamical continuum between hot Jupiters and the weakly irradiated giant planets of our own solar system. We present infrared (IR) light curves and spectra of these models, which depend significantly on incident flux and rotation rate. This provides a way to identify the regime transition in future observations. In some cases, IR light curves can provide constraints on the rotation rate of nonsynchronously rotating planets

  15. Measurement of the solar neutrino capture rate with gallium metal. III. Results for the 2002-2007 data-taking period

    International Nuclear Information System (INIS)

    Abdurashitov, J. N.; Gavrin, V. N.; Gorbachev, V. V.; Gurkina, P. P.; Ibragimova, T. V.; Kalikhov, A. V.; Khairnasov, N. G.; Knodel, T. V.; Mirmov, I. N.; Shikhin, A. A.; Veretenkin, E. P.; Yants, V. E.; Zatsepin, G. T.; Bowles, T. J.; Elliott, S. R.; Teasdale, W. A.; Nico, J. S.; Cleveland, B. T.; Wilkerson, J. F.

    2009-01-01

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keV of 65.4 -3.0 +3.1 (stat) -2.8 +2.6 (syst) SNU. The weighted average of the results of all three Ga solar neutrino experiments, SAGE, Gallex, and GNO, is now 66.1±3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37 Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior 51 Cr neutrino-source experiments with Ga, is 0.87±0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71 Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63 SNU to 66 SNU with an uncertainty of about 4%, in good agreement with experiment. We derive the current value of the neutrino flux produced in the Sun by the proton-proton fusion reaction to be φ pp · =(6.0±0.8)x10 10 /(cm 2 s), which agrees well with the pp flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  16. 57Fe Moessbauer Spectroscopy Studies of Meteorites: Implications for Weathering Rates, Meteorite Flux, and Early Solar System Processes

    International Nuclear Information System (INIS)

    Bland, P. A.; Berry, F. J.; Jull, A. J. T.; Smith, T. B.; Bevan, A. W. R.; Cadogan, J. M.; Sexton, A. S.; Franchi, L. A.; Pillinger, C. T.

    2002-01-01

    Ordinary chondrite finds, terrestrial age dated using 14 C analyses, from different meteorite accumulation sites, have been examined by Moessbauer spectroscopy to quantitatively determine terrestrial oxidation. We observe differences in weathering rates between sites, and also between different chondrite groups. A comparison of weathering over time, and its effect in 'eroding' meteorites, together with the number and mass distribution of meteorites in each region, enables us to derive estimates of the number of meteorite falls over a given mass per year. Studies of how the oxygen isotopic composition of samples varies with weathering indicate that incipient alteration may occur without a pronounced isotopic effect, possibly due to weathering of silicates to topotactically oriented smectite confined spaces where the water volume is limited. This finding has profound implications for the use of oxygen isotopes as a tool in understanding water-rock interaction. It also may reconcile previously contradictory data regarding the nebular or asteroidal location of pre-terrestrial aqueous alteration. Finally, Moessbauer spectroscopy is also found to be a useful tool in determining mineral abundance in carbonaceous chondrites, where a fine-grained matrix makes traditional approaches inapplicable. Again, the results have implications for the modification of chondritic materials in the early solar system.

  17. An equatorial coronal hole at solar minimum

    Science.gov (United States)

    Bromage, B. J. I.; DelZanna, G.; DeForest, C.; Thompson, B.; Clegg, J. R.

    1997-01-01

    The large transequatorial coronal hole that was observed in the solar corona at the end of August 1996 is presented. It consists of a north polar coronal hole called the 'elephant's trunk or tusk'. The observations of this coronal hole were carried out with the coronal diagnostic spectrometer onboard the Solar and Heliospheric Observatory (SOHO). The magnetic field associated with the equatorial coronal hole is strongly connected to that of the active region at its base, resulting in the two features rotating at almost the same rate.

  18. Polycyclic aromatic hydrocarbons (PAHs) skin permeation rates change with simultaneous exposures to solar ultraviolet radiation (UV-S).

    Science.gov (United States)

    Hopf, Nancy B; Spring, Philipp; Hirt-Burri, Nathalie; Jimenez, Silvia; Sutter, Benjamin; Vernez, David; Berthet, Aurelie

    2018-05-01

    Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08-0.1 ng/cm 2 /h) compared to without (0.02-0.26 ng/cm 2 /h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97-13.01 ng/cm 2 /h) compared to with UV-S (0.40-6.35 ng/cm 2 /h). Time until permeation (T lags ) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Solar panel thermal cycling testing by solar simulation and infrared radiation methods

    Science.gov (United States)

    Nuss, H. E.

    1980-01-01

    For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

  20. Low-cost ZnO:Al transparent contact by reactive rotatable magnetron sputtering for Cu(In,Ga)Se2 solar modules

    International Nuclear Information System (INIS)

    Menner, R.; Hariskos, D.; Linss, V.; Powalla, M.

    2011-01-01

    Sputtering ZnO as transparent front contact (TCO) is standard in today's industrial scale Cu(In,Ga)Se 2 (CIGS) module manufacturing. Although innovative concepts like rotatable magnetron sputtering from ceramic targets have been realised, costs are still high due to expensive ceramic targets. Significant cost reductions are expected by using reactive sputtering of metallic targets. Therefore, ZSW and industrial partners investigated the reactive sputtering of Al-doped zinc oxide (ZAO) as TCO on CIGS absorbers of high quality and industrial relevance. The reactive DC sputtering from rotatable magnetron targets is controlled in the transition mode by adjusting oxygen flow and discharge voltage. Optimisation leads to ZAO films with a TCO quality nearly comparable to standard films deposited by DC ceramic sputtering. Scanning electron microscopy, X-ray diffraction, and Hall analyses of the ZAO films are performed. Medium-size CIGS modules are coated with reactively sputtered ZAO, resulting in 12.8% module efficiency and surpassing the efficiency of the ceramic witness device. Cd-free buffered devices are also successfully coated with reactive TCO. Damp heat stability according to IEC61646 is met by all reactively sputtered devices.

  1. Solar pulsations

    International Nuclear Information System (INIS)

    Zirker, J.B.

    1980-01-01

    Oscillations of the surface of the sun, with periods between 5 and 160 min, have been observed by several spectroscopic techniques, and preliminary interpretations have been offered. The 5-min oscillations are global, nonradial, acoustic standing waves in the subsurface zone. Internal differential rotation speeds have been deduced from the Doppler splitting of these waves. Oscillations with longer periods have been reported, but need confirmation. The longest periods offer a tool for investigating the solar interior

  2. 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)

  3. Rotating preventers

    International Nuclear Information System (INIS)

    Tangedahl, M.J.; Stone, C.R.

    1992-01-01

    This paper reports that recent changes in the oil and gas industry and ongoing developments in horizontal and underbalanced drilling necessitated development of a better rotating head. A new device called the rotating blowout preventer (RBOP) was developed by Seal-Tech. It is designed to replace the conventional rotating control head on top of BOP stacks and allows drilling operations to continue even on live (underbalanced) wells. Its low wear characteristics and high working pressure (1,500 psi) allow drilling rig crews to drill safely in slightly underbalanced conditions or handle severe well control problems during the time required to actuate other BOPs in the stack. Drilling with a RBOP allows wellbores to be completely closed in tat the drill floor rather than open as with conventional BOPs

  4. Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

    Energy Technology Data Exchange (ETDEWEB)

    M Ali, M. K., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Ruslan, M. H., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Muthuvalu, M. S., E-mail: sudaram-@yahoo.com, E-mail: jumat@ums.edu.my; Wong, J., E-mail: sudaram-@yahoo.com, E-mail: jumat@ums.edu.my [Unit Penyelidikan Rumpai Laut (UPRL), Sekolah Sains dan Teknologi, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah (Malaysia); Sulaiman, J., E-mail: ysuhaimi@ums.edu.my, E-mail: hafidzruslan@eng.ukm.my; Yasir, S. Md., E-mail: ysuhaimi@ums.edu.my, E-mail: hafidzruslan@eng.ukm.my [Program Matematik dengan Ekonomi, Sekolah Sains dan Teknologi, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah (Malaysia)

    2014-06-19

    The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m{sup 2} and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea of this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R{sup 2}), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.

  5. Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

    International Nuclear Information System (INIS)

    M Ali, M. K.; Ruslan, M. H.; Muthuvalu, M. S.; Wong, J.; Sulaiman, J.; Yasir, S. Md.

    2014-01-01

    The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m 2 and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea of this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R 2 ), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested

  6. Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

    Science.gov (United States)

    M Ali, M. K.; Ruslan, M. H.; Muthuvalu, M. S.; Wong, J.; Sulaiman, J.; Yasir, S. Md.

    2014-06-01

    The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m2 and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea of this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R2), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.

  7. Seismic probing of solar flows using high-degree oscillations

    International Nuclear Information System (INIS)

    Haber, D.A.

    1987-01-01

    Employing solar-oscillation modes of degree 50 ≤ l ≤ 850, the author estimated the equatorial rotation rate with depth, searched for possible anisotropies in power for modes travelling in different directions, and examined the influence of a major flare on the oscillations. Motivated by the need in studying solar rotation for accurate frequency splittings between individual modes, different spatial-filtering methods were evaluated to determine which yield the most-accurate frequencies. A filtering method based on spherical-harmonic projection of the data is found to be superior in this regard. The various filtering techniques are applied to three days of concatenated Doppler-velocity data taken on a long, narrow grid centered on the solar disk. An inversion procedure is then performed to determine the equatorial solar rotation in the upper convection zone. The rotation rate is found to increase to a depth of about 2 Mm before decreasing over the next 14 Mm. Power in sectoral modes traveling along the equator (equatorial modes) is compared to that in poleward-traveling sectoral modes (polar modes). Full-disk Doppler velocities observed before and after a major white-light flare are compared to detect any influence of the flare on the 5-minute oscillations

  8. Sun and solar flares

    Energy Technology Data Exchange (ETDEWEB)

    McKenna-Lawlor, S. (Saint Patrick' s Coll., Maynooth (Ireland))

    1982-07-01

    The subject is discussed under the headings: the sun's core (thermonuclear reactions, energy transfer from core through radiation zone, convection zone, photosphere, chromosphere and corona); the photosphere (convection, granulation, sunspots, magnetic fields, solar cycle, rotation of the sun); solar variability and paleoclimatic records (correlation of low solar activity with increased /sup 14/C production in atmosphere); the chromosphere and corona (turbulence, temperature, coronal streamers, energy transfer); solar flares (cosmic rays, aurorae, spectra, velocity of flares, prominences, mechanisms of flares); the solar wind.

  9. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters.

    Science.gov (United States)

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915 measured samples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rate and heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08.

  10. Flow past a rotating cylinder

    Science.gov (United States)

    Mittal, Sanjay; Kumar, Bhaskar

    2003-02-01

    Flow past a spinning circular cylinder placed in a uniform stream is investigated via two-dimensional computations. A stabilized finite element method is utilized to solve the incompressible Navier Stokes equations in the primitive variables formulation. The Reynolds number based on the cylinder diameter and free-stream speed of the flow is 200. The non-dimensional rotation rate, [alpha] (ratio of the surface speed and freestream speed), is varied between 0 and 5. The time integration of the flow equations is carried out for very large dimensionless time. Vortex shedding is observed for [alpha] cylinder. The results from the stability analysis for the rotating cylinder are in very good agreement with those from direct numerical simulations. For large rotation rates, very large lift coefficients can be obtained via the Magnus effect. However, the power requirement for rotating the cylinder increases rapidly with rotation rate.

  11. Waldmeier's Rules in the Solar and Stellar Dynamos

    Science.gov (United States)

    Pipin, Valery; Kosovichev, Alexander

    2015-08-01

    The Waldmeier's rules [1] establish important empirical relations between the general parameters of magnetic cycles (such as the amplitude, period, growth rate and time profile) on the Sun and solar-type stars [2]. Variations of the magnetic cycle parameters depend on properties of the global dynamo processes operating in the stellar convection zones. We employ nonlinear mean-field axisymmetric dynamo models [3] and calculate of the magnetic cycle parameters, such as the dynamo cycle period, total magnetic and Poynting fluxes for the Sun and solar-type stars with rotational periods from 15 to 30 days. We consider two types of the dynamo models: 1) distributed (D-type) models employing the standard α - effect distributed in the whole convection zone, and 2) Babcock-Leighton (BL-type) models with a non-local α - effect. The dynamo models take into account the principal mechanisms of the nonlinear dynamo generation and saturation, including the magnetic helicity conservation, magnetic buoyancy effects, and the feedback on the angular momentum balance inside the convection zones. Both types of models show that the dynamo generated magnetic flux increases with the increase of the rotation rate. This corresponds to stronger brightness variations. The distributed dynamo model reproduces the observed dependence of the cycle period on the rotation rate for the Sun analogs better than the BL-type model. For the solar-type stars rotating more rapidly than the Sun we find dynamo regimes with multiple periods. Such stars with multiple cycles form a separate branch in the variability-rotation diagram.1. Waldmeier, M., Prognose für das nächste Sonnenfleckenmaximum, 1936, Astron. Nachrichten, 259,262. Soon,W.H., Baliunas,S.L., Zhang,Q.,An interpretation of cycle periods of stellar chromospheric activity, 1993, ApJ, 414,333. Pipin,V.V., Dependence of magnetic cycle parameters on period of rotation in nonlinear solar-type dynamos, 2015, astro-ph: 14125284

  12. Mean-field theory of differential rotation in density stratified turbulent convection

    Science.gov (United States)

    Rogachevskii, I.

    2018-04-01

    A mean-field theory of differential rotation in a density stratified turbulent convection has been developed. This theory is based on the combined effects of the turbulent heat flux and anisotropy of turbulent convection on the Reynolds stress. A coupled system of dynamical budget equations consisting in the equations for the Reynolds stress, the entropy fluctuations and the turbulent heat flux has been solved. To close the system of these equations, the spectral approach, which is valid for large Reynolds and Péclet numbers, has been applied. The adopted model of the background turbulent convection takes into account an increase of the turbulence anisotropy and a decrease of the turbulent correlation time with the rotation rate. This theory yields the radial profile of the differential rotation which is in agreement with that for the solar differential rotation.

  13. Determination of the light-induced degradation rate of the solar cell sensitizer N719 on TiO2 nanocrystalline particles

    DEFF Research Database (Denmark)

    Nour-Mohammadi, Farahnaz; Doan Nguyen, Sau; Boschloo, Gerrit

    2005-01-01

    The oxidative degradation rate, kdeg of the solar cell dye (Bu4N+)2 [Ru(dcbpyH)2(NCS)2]2–, referred to as N719 or [RuL2(NCS)2], was obtained by applying a simple model system. Colloidal solutions of N719-dyed TiO2 particles in acetonitrile were irradiated with 532-nm monochromatic light, and the ...

  14. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters

    Science.gov (United States)

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915measuredsamples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rateand heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08. PMID:26624613

  15. Rotating positron tomographs revisited

    International Nuclear Information System (INIS)

    Townsend, D.; Defrise, M.; Geissbuhler, A.

    1994-01-01

    We have compared the performance of a PET scanner comprising two rotating arrays of detectors with that of the more conventional stationary-ring design. The same total number of detectors was used in each, and neither scanner had septa. For brain imaging, we find that the noise-equivalent count rate is greater for the rotating arrays by a factor of two. Rotating arrays have a sensitivity profile that peaks in the centre of the field of view, both axially and transaxially. In the transaxial plane, this effect offsets to a certain extent the decrease in the number of photons detected towards the centre of the brain due to self-absorption. We have also compared the performance of a rotating scanner to that of a full-ring scanner with the same number of rings. We find that a full-ring scanner with an axial extent of 16.2 cm (24 rings) is a factor of 3.5 more sensitive than a rotating scanner with 40% of the detectors and the same axial extent. (Author)

  16. Microscopic calculation of neutrino capture rates in /sup 69,71/Ga and the detection of solar and galactic neutrinos

    International Nuclear Information System (INIS)

    Grotz, K.; Klapdor, H.V.; Metzinger, J.

    1986-01-01

    Calculations of the neutrino capture cross sections for /sup 69,71/Ga based on a microscopic treatment of the Gamow-Teller matrix elements are presented. A strong enhancement of the cross section for highly energetic neutrinos is found compared to previous phenomenological estimates. As a consequence, the present assumptions on the signal from 8 B neutrinos in 71 Ga have to be revised. A non-negligible solar model dependent background of 8 B neutrinos has to be expected in a gallium solar neutrino experiment together with the pp signal. The calculations yield a larger sensitivity of the gallium detector than assumed previously for galactic neutrinos

  17. Comparative Study for Evaluation of Mass Flow Rate for Simple Solar Still and Active with Heat Pump

    Directory of Open Access Journals (Sweden)

    Hidouri Khaoula

    2017-07-01

    Full Text Available In isolated and arid areas, especially in the almost Maghreb regions, the abundant solar radiation intensity along the year and the available brackish water resources are the two favorable conditions for using solar desalination technology to produce fresh water. The present study is based on the use of three groups of correlation, for evaluating mass transfer. Theoretical results are compared with those obtained experimentally for a Simple Solar Distiller (SSD and a Simple Solar Distiller Hybrid with a Heat Pump (SSDHP stills. Experimental results and those calculated by Lewis number correlation show good agreements. Results obtained by Dunkle, Kumar and Tiwari correlations are not satisfactory with the experimental ones. Theoretical results, as well as statistical analysis, are presented. The model with heat pump ( for two configurations (111 and (001 give more output compared with the model without heat pump ((000 and (110. This results where agree for the use of the statistic results, the error it less with Lewis number as compared with the different correlation.

  18. Astronomical calibration of the Ypresian timescale: implications for seafloor spreading rates and the chaotic behavior of the solar system?

    Directory of Open Access Journals (Sweden)

    T. Westerhold

    2017-09-01

    Full Text Available To fully understand the global climate dynamics of the warm early Eocene with its reoccurring hyperthermal events, an accurate high-fidelity age model is required. The Ypresian stage (56–47.8 Ma covers a key interval within the Eocene as it ranges from the warmest marine temperatures in the early Eocene to the long-term cooling trends in the middle Eocene. Despite the recent development of detailed marine isotope records spanning portions of the Ypresian stage, key records to establish a complete astronomically calibrated age model for the Ypresian are still missing. Here we present new high-resolution X-ray fluorescence (XRF core scanning iron intensity, bulk stable isotope, calcareous nannofossil, and magnetostratigraphic data generated on core material from ODP Sites 1258 (Leg 207, Demerara Rise, 1262, 1263, 1265, and 1267 (Leg 208, Walvis Ridge recovered in the equatorial and South Atlantic Ocean. By combining new data with published records, a 405 kyr eccentricity cyclostratigraphic framework was established, revealing a 300–400 kyr long condensed interval for magnetochron C22n in the Leg 208 succession. Because the amplitudes are dominated by eccentricity, the XRF data help to identify the most suitable orbital solution for astronomical tuning of the Ypresian. Our new records fit best with the La2010b numerical solution for eccentricity, which was used as a target curve for compiling the Ypresian astronomical timescale (YATS. The consistent positions of the very long eccentricity minima in the geological data and the La2010b solution suggest that the macroscopic feature displaying the chaotic diffusion of the planetary orbits, the transition from libration to circulation in the combination of angles in the precession motion of the orbits of Earth and Mars, occurred  ∼  52 Ma. This adds to the geological evidence for the chaotic behavior of the solar system. Additionally, the new astrochronology and revised

  19. Seasonal variations of U.S. mortality rates: Roles of solar ultraviolet-B doses, vitamin D, gene exp ression, and infections.

    Science.gov (United States)

    Grant, William B; Bhattoa, Harjit Pal; Boucher, Barbara J

    2017-10-01

    Death rates in the U.S. show a pronounced seasonality. The broad seasonal variation shows about 25% higher death rates in winter than in summer with an additional few percent increase associated with the Christmas and New Year's holidays. A pronounced increase in death rates also starts in mid-September, shortly after the school year begins. The causes of death with large contributions to the observed seasonality include diseases of the circulatory system; the respiratory system; the digestive system; and endocrine, nutritional, and metabolic diseases. Researchers have identified several factors showing seasonal variation that could possibly explain the seasonal variations in mortality rate. These factors include seasonal variations in solar ultraviolet-B(UVB) doses and serum 25-hydroxyvitamin D [25(OH)D] concentrations, gene expression, ambient temperature and humidity, UVB effects on environmental pathogen load, environmental pollutants and allergens, and photoperiod (or length of day). The factors with the strongest support in this analysis are seasonal variations in solar UVB doses and 25(OH)D concentrations. In the U.S., population mean 25(OH)D concentrations range from 21ng/mL in March to 28ng/mL in August. Measures to ensure that all people had 25(OH)D concentrations >36ng/mL year round would probably reduce death rates significantly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Solar Stereoscopy and Tomography

    Directory of Open Access Journals (Sweden)

    Markus J. Aschwanden

    2011-10-01

    Full Text Available We review stereoscopic and tomographic methods used in the solar corona, including ground-based and space-based measurements, using solar rotation or multiple spacecraft vantage points, in particular from the STEREO mission during 2007--2010. Stereoscopic and tomographic observations in the solar corona include large-scale structures, streamers, active regions, coronal loops, loop oscillations, acoustic waves in loops, erupting filaments and prominences, bright points, jets, plumes, flares, CME source regions, and CME-triggered global coronal waves. Applications in the solar interior (helioseismic tomography and reconstruction and tracking of CMEs from the outer corona and into the heliosphere (interplanetary CMEs are not included.

  1. The structure of rotational discontinuities

    International Nuclear Information System (INIS)

    Neugebauer, M.

    1989-01-01

    This study examines the structures of a set of rotational discontinuities detected in the solar wind by the ISEE-3 spacecraft. It is found that the complexity of the structure increases as the angle θ between the propagation vector k and the magnetic field decreases. For rotational discontinuities that propagate at a large angle to the field with an ion (left-hand) sense of rotation, the magnetic hodograms tend to be flattened, in agreement with prior numerical simulations. When θ is large, angular overshoots are often observed at one or both ends of the discontinuity. When the propagation is nearly parallel to the field (i.e., when θ is small), many different types of structure are seen, ranging from straight lines, the S-shaped curves, to complex, disorganized shapes

  2. Effects on stratospheric moistening by rates of change of aerosol optical depth and ozone due to solar activity in extra-tropics

    Science.gov (United States)

    Saha, U.; Maitra, A.

    2014-11-01

    The solar-induced changes in ozone and aerosol optical depth have relative effects on stratospheric moistening at upper troposphere/lower stratosphere region. Wavelet-based multi-scale principal component analysis technique has been applied to de-noise component of quasi-biennial oscillation and El Niño-Southern Oscillation from ozone and aerosol optical depth variations. Rate of change of aerosol optical depth sharply increases indicating a positive gradient whereas rate of change of ozone sharply decreases indicating a negative gradient with solar activity during the years 2004-2010. It is also observed that with increase of rate of change of aerosol optical depth, there is a sharp increase of stratospheric moistening caused by enhanced deep convection. On the contrary, with the increase of stratospheric moistening, there is a sharp decrease of rate of change of ozone resulting in a cross-over between the two parameters. An increase in aerosol optical depth may cause a significant increase in the gradient of vertical temperature profile, as well as formation of cloud condensation nuclei, clouds and hence rainfall. This may lead to formation of strong convective system in the atmosphere that is essential for vertical transfer of water vapour in the tropics percolating tropical tropopause layer and depleting stratospheric ozone in the extra-tropics.

  3. Pemodelan Matematik Kinerja Pengering Surya Efek Rumah Kaca (ERK-Hibrid Menggunakan Rak Berputar secara Vertikal (Mathematical Modeling Performance of Greenhouse Effect (GHE-Hybrid Solar Dryer with a Vertical Rotating Rack

    Directory of Open Access Journals (Sweden)

    Sigit Triwahyudi

    2016-12-01

    Full Text Available This paper presents a performance test and mathematical modeling of greenhouse effect (GHE-Hybrid solar dryer with vertical rotating rack. The dryer consists of a greenhouse dryer (1100 × 860 × 1300 mm with eight rack and additional heating system consists of a flat plate collector (1,04 m2, a hot water storage tank (197 liters and a heat exchanger. To investigate the performance of solar greenhouse dryer, five experimental variation speed of rack were conducted (1, 4, 7, 10 rpm and without rotation. Materials used in the experiment are local cardamom (Amomum cardamomum Wild. Weight of each experiment  about  9 to 10 kg. The average temperature of the hot water storage tank varies from 50.0 to 55.0 °C, drying air  temperature between 38.9 to 45.9 °C, while the relative humidity (RH of drying chamber ranged from 32.1 to 47.4 %. Variation of rotational speed affects on the uniformity of product temperature and water content in each rack drying. At rotation 1 rpm  (experiment II, obtained  as the best conditions (temperature and moisture content are most uniform. Increasing rotational speed of rack causes increasing in standard deviation of  product temperature and moisture content. To simulate the performance of the dryer, mathematical modeling based on heat  and mass transfer and a thin layer drying  approaches were conducted. Equations solved numerically using the finite difference Euler with Visual Basic Application (VBA program on Excel. Validation was conducted by comparing the calculation results of mathematical modeling (data prediction with measurement data (data observation. Criterion validity was determined by  the value of the coefficient of determination (R2, the value of RMSD and MAPD. Mathematical models that have been developed can be described precisely the temperature of the hot water storage tank, temperature of the drying chamber, temperature of the product as well as a moisture content decrease.   ABSTRAK Makalah

  4. Effect of Projectile Rotation Rate on Lateral Effect of PELE Penetrating Reinforced Concrete Target%弹丸转速对PELE侵彻钢筋混凝土靶横向效应的影响

    Institute of Scientific and Technical Information of China (English)

    何俊; 徐立志; 程春; 郑绍君; 杜忠华; 蒋洪章

    2017-01-01

    为了研究弹丸转速对横向效应增强型侵彻体(PELE)侵彻钢筋混凝土靶横向效应的影响,运用ANSYS/LS-DYNA软件在着靶速度600、700和800m/s条件下,对具有不同转速的PELE侵彻钢筋混凝土靶进行数值模拟,并通过试验方法对不同着靶条件下的仿真模型进行验证.结果表明,开孔尺寸的数值模拟结果与实验结果之间的误差小于5%,仿真模型能够准确模拟PELE侵彻钢筋混凝土靶的过程;随着转速的不断提高,损失更多的转速动能转化为钢筋混凝土靶开孔破坏所需的能量,使钢筋混凝土靶的开孔尺寸增大;在同一着靶速度下,转速从10000r/min提高至25000r/min,开孔尺寸提高了约(8±2)%.因此,在同一着靶速度下,增加弹丸转速有利于提高PELE对钢筋混凝土靶的开孔尺寸.%To study the effect of projectile rotation rate on the lateral effect of penetrator with enhanced lateral effects (PELE)penetrating reinforced concrete target, the numerical simulation of PELE penetrating reinforced concrete target with different rotation rates was performed under the condition of three impact target velocities of 600,700 and 800m/s,and the simulation model under the conditions of different impact target was verified by testing method.The results show that the error of opening size between the simulation results and the experimental ones is less than 5%, showing that the simulation model can accurately simulate the process of PELE penetrating reinforced concrete target.With increasing the rotation rate, more rotation rate kinetic energy lost translates into the energy that used to break the reinforced concrete target and make the opening size of reinforced concrete target increase.Under the same impact target velocity, opening size is improved by (8±2)% when the rotation rate increases from 10000r/min to 25000r/min.Therefore, increasing projectile rotation rate is beneficial to improve the opening size of the PELE penetrating

  5. The influence of nitrogen fertiliser rate and crop rotation on soil methane flux in rain-fed potato fields in Wuchuan County, China

    International Nuclear Information System (INIS)

    Wang, Liwei; Pan, Zhihua; Xu, Hui; Wang, Cheng; Gao, Lin; Zhao, Peiyi; Dong, Zhiqiang; Zhang, Jingting; Cui, Guohui; Wang, Sen; Han, Guolin; Zhao, Hui

    2015-01-01

    As one of the important greenhouse gases, the characteristics and principles of methane exchange characteristics in cultivated lands have become hot topics in current climate change research. This study examines the influences of nitrogen fertilisation, temperature and soil water content on methane exchange characteristic and methane exchange functional gene-pmoA gene abundance based on experimental observations of methane exchange fluxes using the static chamber–gas chromatographic method and measurements of methanotroph gene copy numbers in three growing periods by real-time PCR in rain-fed potato fields. The results indicate that the rain-fed potato fields were a CH_4 sink with an average annual methane absorption (negative emission) of 940.8 ± 103.2 g CH_4-C/ha/year. The cumulative methane absorption first exhibited flat and subsequently increasing trend with the increase of nitrogen fertilisation from 0 ~ 135 kg N·ha"−"1. Methane cumulative absorption significantly increased with the increase of temperature when temperatures were below 19.6 °C. Methane oxidation capacity (methanotroph pmoA gene copy numbers) showed an increasing and subsequently decreasing trend with the increase of soil moisture. Crop rotation was observed to increase the methane absorption in rain-fed potato fields and nearly one time higher than that under continuous cropping. A mechanism concept model of the methane exchange in rain-fed potato fields was advanced in this paper. - Highlights: • Rain-fed potato fields were a CH_4 sink. • Increased nitrogen fertilisation and temperature led to higher CH_4 absorption. • CH_4 oxidation capacity showed a parabolic trend with soil moisture increased. • Crop rotation increased CH_4 absorption one time higher than continuous cropping. • A mechanism concept model of the CH_4 exchange in potato fields was advanced.

  6. The influence of nitrogen fertiliser rate and crop rotation on soil methane flux in rain-fed potato fields in Wuchuan County, China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liwei [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); College of Agronomy, Shenyang Agricultural University, Shenyang 110866 (China); Wuchuan Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture Wuchuan 011700 (China); Pan, Zhihua, E-mail: panzhihua@cau.edu.cn [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Wuchuan Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture Wuchuan 011700 (China); Xu, Hui [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Cheng [College of Agricultural and Biotechnology, China Agricultural University, Beijing 100193 (China); Gao, Lin [School of Resources and Environmental, Anhui Agricultural University, Hefei 230036 (China); Zhao, Peiyi [Institute of Resources Environmental and Detection Technology, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Huhhot 010031 (China); Wuchuan Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture Wuchuan 011700 (China); Dong, Zhiqiang; Zhang, Jingting; Cui, Guohui; Wang, Sen; Han, Guolin; Zhao, Hui [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Wuchuan Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture Wuchuan 011700 (China)

    2015-12-15

    As one of the important greenhouse gases, the characteristics and principles of methane exchange characteristics in cultivated lands have become hot topics in current climate change research. This study examines the influences of nitrogen fertilisation, temperature and soil water content on methane exchange characteristic and methane exchange functional gene-pmoA gene abundance based on experimental observations of methane exchange fluxes using the static chamber–gas chromatographic method and measurements of methanotroph gene copy numbers in three growing periods by real-time PCR in rain-fed potato fields. The results indicate that the rain-fed potato fields were a CH{sub 4} sink with an average annual methane absorption (negative emission) of 940.8 ± 103.2 g CH{sub 4}-C/ha/year. The cumulative methane absorption first exhibited flat and subsequently increasing trend with the increase of nitrogen fertilisation from 0 ~ 135 kg N·ha{sup −1}. Methane cumulative absorption significantly increased with the increase of temperature when temperatures were below 19.6 °C. Methane oxidation capacity (methanotroph pmoA gene copy numbers) showed an increasing and subsequently decreasing trend with the increase of soil moisture. Crop rotation was observed to increase the methane absorption in rain-fed potato fields and nearly one time higher than that under continuous cropping. A mechanism concept model of the methane exchange in rain-fed potato fields was advanced in this paper. - Highlights: • Rain-fed potato fields were a CH{sub 4} sink. • Increased nitrogen fertilisation and temperature led to higher CH{sub 4} absorption. • CH{sub 4} oxidation capacity showed a parabolic trend with soil moisture increased. • Crop rotation increased CH{sub 4} absorption one time higher than continuous cropping. • A mechanism concept model of the CH{sub 4} exchange in potato fields was advanced.

  7. Anelastic Models of Fully-Convective Stars: Differential Rotation, Meridional Circulation and Residual Entropy

    Science.gov (United States)

    Sainsbury-Martinez, Felix; Browning, Matthew; Miesch, Mark; Featherstone, Nicholas A.

    2018-01-01

    Low-Mass stars are typically fully convective, and as such their dynamics may differ significantly from sun-like stars. Here we present a series of 3D anelastic HD and MHD simulations of fully convective stars, designed to investigate how the meridional circulation, the differential rotation, and residual entropy are affected by both varying stellar parameters, such as the luminosity or the rotation rate, and by the presence of a magnetic field. We also investigate, more specifically, a theoretical model in which isorotation contours and residual entropy (σ‧ = σ ‑ σ(r)) are intrinsically linked via the thermal wind equation (as proposed in the Solar context by Balbus in 2009). We have selected our simulation parameters in such as way as to span the transition between Solar-like differential rotation (fast equator + slow poles) and ‘anti-Solar’ differential rotation (slow equator + fast poles), as characterised by the convective Rossby number and △Ω. We illustrate the transition from single-celled to multi-celled MC profiles, and from positive to negative latitudinal entropy gradients. We show that an extrapolation involving both TWB and the σ‧/Ω link provides a reasonable estimate for the interior profile of our fully convective stars. Finally, we also present a selection of MHD simulations which exhibit an almost unsuppressed differential rotation profile, with energy balances remaining dominated by kinetic components.

  8. Effect of rotation on convective mass transfer in rotating channels

    International Nuclear Information System (INIS)

    Pharoah, J.G.; Djilali, N.

    2002-01-01

    Laminar flow and mass transfer in rotating channels is investigated in the context of centrifugal membrane separation. The effect of orientation with respect to the rotational axis is examined for rectangular channels of aspect ratio 3 and the Rossby number is varied from 0.3 to 20.9. Both Ro and the channel orientation are found to have a significant effect on the flow. Mass transfer calculations corresponding to reverse osmosis desalination are carried out at various operating pressures and all rotating cases exhibit significant process enhancements at relatively low rotation rates. Finally, while it is common in the membrane literature to correlate mass transfer performance with membrane shear rates this is shown not to be valid in the cases presented herein. (author)

  9. Extreme learning machine: a new alternative for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters.

    Science.gov (United States)

    Liu, Zhijian; Li, Hao; Tang, Xindong; Zhang, Xinyu; Lin, Fan; Cheng, Kewei

    2016-01-01

    Heat collection rate and heat loss coefficient are crucial indicators for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, wasting too much time and manpower. To address this problem, we previously used artificial neural networks and support vector machine to develop precise knowledge-based models for predicting the heat collection rates and heat loss coefficients of water-in-glass evacuated tube solar water heaters, setting the properties measured by "portable test instruments" as the independent variables. A robust software for determination was also developed. However, in previous results, the prediction accuracy of heat loss coefficients can still be improved compared to those of heat collection rates. Also, in practical applications, even a small reduction in root mean square errors (RMSEs) can sometimes significantly improve the evaluation and business processes. As a further study, in this short report, we show that using a novel and fast machine learning algorithm-extreme learning machine can generate better predicted results for heat loss coefficient, which reduces the average RMSEs to 0.67 in testing.

  10. Estimation of the reaction rate for the formation of CH3O from H + H2CO - Implications for chemistry in the solar system

    Science.gov (United States)

    Yung, Yuk L.; Drew, William A.; Pinto, Joseph P.; Friedl, Randall R.

    1988-01-01

    Troe's (1977) approximate theory is presently used in conjunction with transition state theory to estimate the rate coefficient of the reaction by which CO is reduced to CH4; attention is given to the role that may be played in the reduction process by the formation of the CH3O radical from H + H2CO. Attention is given to the implications of such a reaction (1) for the CO chemistry on Jupiter and within the solar nebula, (2) for the interpretation of such experimental results as those of Bar-Nun and Shaviv (1975) and Bar-Nun and Chang (1983), and (3) for organic synthesis in the prebiotic terrestrial atmosphere.

  11. Helioseismology and the Solar Interior Dynamics

    Indian Academy of Sciences (India)

    tribpo

    gives information on the internal solar rotation: while differential rotation exists in the ... show that lithium has been depleted by a factor of about 140 compared to the proto- solar value ... 2.1 Theory of element settling in the Sun and the stars.

  12. Variations in Solar Parameters and Cosmic Rays with Solar Magnetic Polarity

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S. [Department of Earth Science Education, Chonnam National University, Gwangju, 61186 (Korea, Republic of); Yi, Y., E-mail: suyeonoh@jnu.ac.kr [Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon, 34134 (Korea, Republic of)

    2017-05-01

    The sunspot number varies with the 11-year Schwabe cycle, and the solar magnetic polarity reverses every 11 years approximately at the solar maximum. Because of polarity reversal, the difference between odd and even solar cycles is seen in solar activity. In this study, we create the mean solar cycle expressed by phase using the monthly sunspot number for all solar cycles 1–23. We also generate the mean solar cycle for sunspot area, solar radio flux, and cosmic ray flux within the allowance of observational range. The mean solar cycle has one large peak at solar maximum for odd solar cycles and two small peaks for most even solar cycles. The odd and even solar cycles have the statistical difference in value and shape at a confidence level of at least 98%. For solar cycles 19–23, the second peak in the even solar cycle is larger than the first peak. This result is consistent with the frequent solar events during the declining phase after the solar maximum. The difference between odd and even solar cycles can be explained by a combined model of polarity reversal and solar rotation. In the positive/negative polarity, the polar magnetic field introduces angular momentum in the same/opposite direction as/to the solar rotation. Thus the addition/subtraction of angular momentum can increase/decrease the motion of plasma to support the formation of sunspots. Since the polarity reverses at the solar maximum, the opposite phenomenon occurs in the declining phase.

  13. The sun as a star: Solar phenomena and stellar applications

    International Nuclear Information System (INIS)

    Noyes, R.W.

    1981-01-01

    Our Sun is a run-of-the-mill star, having no obvious extremes of stellar properties. For this reason it is perhaps more, rather than less, interesting as an astrophysical object, for its sameness to other stars suggests that in studying the Sun, we are studying at close hand common, rather than unusual stellar phenomena. Conversely, comparative study of the Sun and other solar-type stars is an invaluable tool for solar physics, for two reasons: First, it allows us to explore how solar properties and phenomena depend on parameters we cannot vary on the Sun - most fundamentally, rotation rate and mass. Second, study of solar-like stars of different ages allows us to see how stellar and solar phenomena depend on age; study of other stars may be one of the best ways to infer the earlier history of the Sun, as well as its future history. In this review we shall concentrate on phenomena common to the Sun and solar-type (main sequence) stars with different fundamental properties such as mass, age, and rotation. (orig.)

  14. Faraday rotation measurements at Ootacamund

    Science.gov (United States)

    Sethia, G.; Chandra, H.; Deshpande, M. R.; Rastogi, R. G.

    1978-01-01

    The results of Faraday rotation measurements made at Ootacamund during ATS-6 phase II are presented. For summer and equinoctial months, even though no clear noon bite-out is observed in the variation of Faraday a decrease is observed in the rate of increase of rotation around 0900-1000 hours LT. This is attributed to the 'fountain effect' which is responsible for the noontime bite-out in F2-region peak electron density.

  15. The influence of nitrogen fertiliser rate and crop rotation on soil methane flux in rain-fed potato fields in Wuchuan County, China.

    Science.gov (United States)

    Wang, Liwei; Pan, Zhihua; Xu, Hui; Wang, Cheng; Gao, Lin; Zhao, Peiyi; Dong, Zhiqiang; Zhang, Jingting; Cui, Guohui; Wang, Sen; Han, Guolin; Zhao, Hui

    2015-12-15

    As one of the important greenhouse gases, the characteristics and principles of methane exchange characteristics in cultivated lands have become hot topics in current climate change research. This study examines the influences of nitrogen fertilisation, temperature and soil water content on methane exchange characteristic and methane exchange functional gene-pmoA gene abundance based on experimental observations of methane exchange fluxes using the static chamber-gas chromatographic method and measurements of methanotroph gene copy numbers in three growing periods by real-time PCR in rain-fed potato fields. The results indicate that the rain-fed potato fields were a CH4 sink with an average annual methane absorption (negative emission) of 940.8±103.2 g CH4-C/ha/year. The cumulative methane absorption first exhibited flat and subsequently increasing trend with the increase of nitrogen fertilisation from 0~135 kg N·ha(-1). Methane cumulative absorption significantly increased with the increase of temperature when temperatures were below 19.6 °C. Methane oxidation capacity (methanotroph pmoA gene copy numbers) showed an increasing and subsequently decreasing trend with the increase of soil moisture. Crop rotation was observed to increase the methane absorption in rain-fed potato fields and nearly one time higher than that under continuous cropping. A mechanism concept model of the methane exchange in rain-fed potato fields was advanced in this paper. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Analytically calculated post-Keplerian range and range-rate perturbations: the solar Lense-Thirring effect and BepiColombo

    Science.gov (United States)

    Iorio, Lorenzo

    2018-05-01

    We analytically calculate the time series for the perturbations Δ ρ \\left(t\\right), Δ \\dot{ρ }\\left(t\\right) induced by a general disturbing acceleration A on the mutual range ρ and range-rate \\dot{ρ } of two test particles A, B orbiting the same spinning body. We apply it to the general relativistic Lense-Thirring effect, due to the primary's spin S, and the classical perturbation arising from its quadrupole mass moment J2 for arbitrary orbital geometries and orientation of the source's symmetry axis {\\hat{S}}. The Earth-Mercury range and range-rate are nominally affected by the Sun's gravitomagnetic field to the 10 m, 10-3 cm s-1 level, respectively, during the extended phase (2026-2028) of the forthcoming BepiColombo mission to Mercury whose expected tracking accuracy is of the order of ≃0.1 m, 2 × 10-4 cm s-1. The competing signatures due to the solar quadrupole J_2^{\\odot }, if modelled at the σ _{J_2^{\\odot }}˜eq 10^{-9} level of the latest planetary ephemerides INPOP17a, are nearly 10 times smaller than the relativistic gravitomagnetic effects. The position and velocity vectors \\boldsymbol {r}, \\boldsymbol {v} of Mercury and Earth are changed by the solar Lense-Thirring effect by about 10 m, 1.5 m and 10-3 cm s-1, 10-5 cm s-1, respectively, over 2 yr; neglecting such shifts may have an impact on long-term integrations of the inner Solar system dynamics over ˜Gyr time-scales.

  17. Meridional Motions and Reynolds Stress Determined by Using Kanzelhöhe Drawings and White Light Solar Images from 1964 to 2016

    Science.gov (United States)

    Ruždjak, Domagoj; Sudar, Davor; Brajša, Roman; Skokić, Ivica; Poljančić Beljan, Ivana; Jurdana-Šepić, Rajka; Hanslmeier, Arnold; Veronig, Astrid; Pötzi, Werner

    2018-04-01

    Sunspot position data obtained from Kanzelhöhe Observatory for Solar and Environmental Research (KSO) sunspot drawings and white light images in the period 1964 to 2016 were used to calculate the rotational and meridional velocities of the solar plasma. Velocities were calculated from daily shifts of sunspot groups and an iterative process of calculation of the differential rotation profiles was used to discard outliers. We found a differential rotation profile and meridional motions in agreement with previous studies using sunspots as tracers and conclude that the quality of the KSO data is appropriate for analysis of solar velocity patterns. By analyzing the correlation and covariance of meridional velocities and rotation rate residuals we found that the angular momentum is transported towards the solar equator. The magnitude and latitudinal dependence of the horizontal component of the Reynolds stress tensor calculated is sufficient to maintain the observed solar differential rotation profile. Therefore, our results confirm that the Reynolds stress is the dominant mechanism responsible for transport of angular momentum towards the solar equator.

  18. Solar neutrinos and nonradial solar oscillations

    International Nuclear Information System (INIS)

    Zatsepin, G.T.; Gavryuseva, E.A.; Kopysov, Yu.S.

    1980-01-01

    The problem of origin of surface solar oscillations is considered. It is assumed that generation of oscillations is performed by the solar nucleus. The necessary excitation condition for gravitational oscillations of the solar nucleus is a sharp decrease of the oscillation amplitude outside the nucleus, where the nuclear reaction rates are small and only radiation losses are considerable. It is shown that the specific singularities of gravitational wave propagation in solar entrails permit to attain a significant reduction of the oscillation amplitude. The solar entrails can serve as an effective trap for gravitational waves, if the substance of the solar nucleus is close to the state of convectional equilibrium. In order that the g 1 quadrupole mode of the solar nucleus has a period of 2h 40 min and sharply decreases in the solar mantle, it is enough that only the external part of the solar nucleus is close to the state of convectional equilibrium. Closeness of the solar nucleus to the state of convectional equilibrium is an argument in favour of its periodic mixing. Periodic mixing of the solar nucleus can serve as a cause of a low counting rate of solar neutrinos in R.Davis chlorous detector

  19. High-Rate Fabrication of a-Si-Based Thin-Film Solar Cells Using Large-Area VHF PECVD Processes

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Xunming [University of Toledo; Fan, Qi Hua

    2011-12-31

    The University of Toledo (UT), working in concert with it’s a-Si-based PV industry partner Xunlight Corporation (Xunlight), has conducted a comprehensive study to develop a large-area (3ft x 3ft) VHF PECVD system for high rate uniform fabrication of silicon absorber layers, and the large-area VHF PECVD processes to achieve high performance a-Si/a-SiGe or a-Si/nc-Si tandem junction solar cells during the period of July 1, 2008 to Dec. 31, 2011, under DOE Award No. DE-FG36-08GO18073. The project had two primary goals: (i) to develop and improve a large area (3 ft × 3 ft) VHF PECVD system for high rate fabrication of > = 8 Å/s a-Si and >= 20 Å/s nc-Si or 4 Å/s a-SiGe absorber layers with high uniformity in film thicknesses and in material structures. (ii) to develop and optimize the large-area VHF PECVD processes to achieve high-performance a-Si/nc-Si or a-Si/a-SiGe tandem-junction solar cells with >= 10% stable efficiency. Our work has met the goals and is summarized in “Accomplishments versus goals and objectives”.

  20. Solar UV irradiation-induced production of N2O from plant surfaces - low emissions rates but all over the world.

    Science.gov (United States)

    Mikkelsen, T. N.; Bruhn, D.; Ambus, P.

    2016-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2 h-1, mostly due to the UV component. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  1. Spacecraft with gradual acceleration of solar panels

    Science.gov (United States)

    Merhav, Tamir R. (Inventor); Festa, Michael T. (Inventor); Stetson, Jr., John B. (Inventor)

    1996-01-01

    A spacecraft (8) includes a movable appendage such as solar panels (12) operated by a stepping motor (28) driven by pulses (311). In order to reduce vibration andor attitude error, the drive pulses are generated by a clock down-counter (312) with variable count ratio. Predetermined desired clock ratios are stored in selectable memories (314a-d), and the selected ratio (R) is coupled to a comparator (330) together with the current ratio (C). An up-down counter (340) establishes the current count-down ratio by counting toward the desired ratio under the control of the comparator; thus, a step change of solar panel speed never occurs. When a direction change is commanded, a flag signal generator (350) disables the selectable memories, and enables a further store (360), which generates a count ratio representing a very slow solar panel rotational rate, so that the rotational rate always slows to a low value before direction is changed. The principles of the invention are applicable to any movable appendage.

  2. Rotator cuff exercises

    Science.gov (United States)

    ... 25560729 . Read More Frozen shoulder Rotator cuff problems Rotator cuff repair Shoulder arthroscopy Shoulder CT scan Shoulder MRI scan Shoulder pain Patient Instructions Rotator cuff - self-care Shoulder surgery - discharge Using your ...

  3. Relation between radio luminosity and rotation for late-type stars

    International Nuclear Information System (INIS)

    Stewart, R.T.; Innis, J.L.; Slee, O.B.; Nelson, G.J.; Wright, A.E.

    1988-01-01

    A relation is found between peak radio luminosities measured at 8 GHz and the rotational velocity of 51 late-type F, G, and K stars (including the sun). The sample includes both single stars and active components of close binary systems, with equatorial surface velocities ranging from 1 to 100 km/s. A gyrosynchrotron source model originally developed to explain solar microwave bursts could explain the relation. The main parameter depending on rotation rate is the filling factor, i.e., the fraction of the stellar surface and corona occupied by intense magnetic fields. As the rotation speed increases, the scale size of the coronal structures emitting microwave gyrosynchrotron radiation increases, and there is a corresponding increase in the area of the surface covered by intense starspot magnetic fields. However, the peak magnetic field of the starspots probably does not increase significantly above observed sunspot values. 47 references

  4. The sun and solar flares

    International Nuclear Information System (INIS)

    McKenna-Lawlor, S.

    1982-01-01

    The subject is discussed under the headings: the sun's core (thermonuclear reactions, energy transfer from core through radiation zone, convection zone, photosphere, chromosphere and corona); the photosphere (convection, granulation, sunspots, magnetic fields, solar cycle, rotation of the sun); solar variability and paleoclimatic records (correlation of low solar activity with increased 14 C production in atmosphere); the chromosphere and corona (turbulence, temperature, coronal streamers, energy transfer); solar flares (cosmic rays, aurorae, spectra, velocity of flares, prominences, mechanisms of flares); the solar wind. (U.K.)

  5. Optimizing Water Exchange Rates and Rotational Mobility for High-Relaxivity of a Novel Gd-DO3A Derivative Complex Conjugated to Inulin as Macromolecular Contrast Agents for MRI.

    Science.gov (United States)

    Granato, Luigi; Vander Elst, Luce; Henoumont, Celine; Muller, Robert N; Laurent, Sophie

    2018-02-01

    Thanks to the understanding of the relationships between the residence lifetime τ M of the coordinated water molecules to macrocyclic Gd-complexes and the rotational mobility τ R of these structures, and according to the theory for paramagnetic relaxation, it is now possible to design macromolecular contrast agents with enhanced relaxivities by optimizing these two parameters through ligand structural modification. We succeeded in accelerating the water exchange rate by inducing steric compression around the water binding site, and by removing the amide function from the DOTA-AA ligand [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono(p-aminoanilide)] (L) previously designed. This new ligand 10[2(1-oxo-1-p-propylthioureidophenylpropyl]-1,4,7,10-tetraazacyclodecane-1,4,7-tetraacetic acid (L 1 ) was then covalently conjugated to API [O-(aminopropyl)inulin] to get the complex API-(GdL 1 )x with intent to slow down the rotational correlation time (τ R ) of the macromolecular complex. The evaluation of the longitudinal relaxivity at different magnetic fields and the study of the 17 O-NMR at variable temperature of the low-molecular-weight compound (GdL 1 ) showed a slight decrease of the τ M value (τM310 = 331 ns vs. τM310 = 450 ns for the GdL complex). Consequently to the increase of the size of the API-(GdL 1 )x complex, the rotational correlation time becomes about 360 times longer compared to the monomeric GdL 1 complex (τ R  = 33,700 ps), which results in an enhanced proton relaxivity. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

  6. 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.

  7. Modelling solar-like oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Eggenberger, P; Miglio, A [Institut d' Astrophysique et de Geophysique de l' Universite de Liege, 17 Allee du 6 Aout, B-4000 Liege (Belgium); Carrier, F [Institute of Astronomy, University of Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Mathis, S [CEA/DSM/DAPNIA/Service d' Astrophysique, CEA/Saclay, AIM-Unite Mixte de Recherche CEA-CNRS-Universite Paris VII, UMR 7158, 91191 Gif-sur-Yvette Cedex (France)], E-mail: eggenberger@Qastro.ulg.ac.be

    2008-10-15

    The computation of models of stars for which solar-like oscillations have been observed is discussed. After a brief intoduction on the observations of solar-like oscillations, the modelling of isolated stars and of stars belonging to a binary system is presented with specific examples of recent theoretical calibrations. Finally the input physics introduced in stellar evolution codes for the computation of solar-type stars is discussed with a peculiar emphasis on the modelling of rotation for these stars.

  8. Design and Development of a Solar Thermal Collector with Single Axis Solar Tracking Mechanism

    Directory of Open Access Journals (Sweden)

    Theebhan Mogana

    2016-01-01

    Full Text Available The solar energy is a source of energy that is abundant in Malaysia and can be easily harvested. However, because of the rotation of the Earth about its axis, it is impossible to harvest the solar energy to the maximum capacity if the solar thermal collector is placed fix to a certain angle. In this research, a solar thermal dish with single axis solar tracking mechanism that will rotate the dish according to the position of the sun in the sky is designed and developed, so that more solar rays can be reflected to a focal point and solar thermal energy can be harvested from the focal point. Data were collected for different weather conditions and performance of the solar thermal collector with a solar tracker were studied and compared with stationary solar thermal collector.

  9. Solar active region display system

    Science.gov (United States)

    Golightly, M.; Raben, V.; Weyland, M.

    2003-04-01

    The Solar Active Region Display System (SARDS) is a client-server application that automatically collects a wide range of solar data and displays it in a format easy for users to assimilate and interpret. Users can rapidly identify active regions of interest or concern from color-coded indicators that visually summarize each region's size, magnetic configuration, recent growth history, and recent flare and CME production. The active region information can be overlaid onto solar maps, multiple solar images, and solar difference images in orthographic, Mercator or cylindrical equidistant projections. Near real-time graphs display the GOES soft and hard x-ray flux, flare events, and daily F10.7 value as a function of time; color-coded indicators show current trends in soft x-ray flux, flare temperature, daily F10.7 flux, and x-ray flare occurrence. Through a separate window up to 4 real-time or static graphs can simultaneously display values of KP, AP, daily F10.7 flux, GOES soft and hard x-ray flux, GOES >10 and >100 MeV proton flux, and Thule neutron monitor count rate. Climatologic displays use color-valued cells to show F10.7 and AP values as a function of Carrington/Bartel's rotation sequences - this format allows users to detect recurrent patterns in solar and geomagnetic activity as well as variations in activity levels over multiple solar cycles. Users can customize many of the display and graph features; all displays can be printed or copied to the system's clipboard for "pasting" into other applications. The system obtains and stores space weather data and images from sources such as the NOAA Space Environment Center, NOAA National Geophysical Data Center, the joint ESA/NASA SOHO spacecraft, and the Kitt Peak National Solar Observatory, and can be extended to include other data series and image sources. Data and images retrieved from the system's database are converted to XML and transported from a central server using HTTP and SOAP protocols, allowing

  10. Rotational cross sections and rate coefficients of aluminium monoxide AlO(X2Σ+) induced by its collision with He(1 S) at low temperature

    Science.gov (United States)

    Tchakoua, Théophile; Nkot Nkot, Pierre René; Fifen, Jean Jules; Nsangou, Mama; Motapon, Ousmanou

    2018-06-01

    We present the first potential energy surface (PES) for the AlO(X2Σ+)-He(1 S) van der Waals complex. This PES has been calculated at the RCCSD(T) level of theory. The mixed Gaussian/Exponential Extrapolation Scheme of complete basis set [CBS(D,T,Q)] was employed. The PES was fitted using global analytical method. This fitted PES was used subsequently in the close-coupling approach for the computation of the state-to-state collisional excitation cross sections of the fine-structure levels of the AlO-He complex. Collision energies were taken up to 2500 cm-1 and they yield after thermal averaging, state-to-state rate coefficients up to 300 K. The propensity rules between the lowest fine-structure levels were studied. These rules show, on one hand, a strong propensity in favour of odd ΔN transitions, and on the other hand, that cross sections and collisional rate coefficients for Δj = ΔN transitions are larger than those for Δj ≠ ΔN transitions.

  11. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Bohr, A.

    1977-01-01

    History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

  12. Tokamak rotation and charge exchange

    International Nuclear Information System (INIS)

    Hazeltine, R.D.; Rowan, W.L.; Solano, E.R.; Valanju, P.M.

    1991-01-01

    In the absence of momentum input, tokamak toroidal rotation rates are typically small - no larger in particular than poloidal rotation - even when the radial electric field is strong, as near the plasma edge. This circumstance, contradicting conventional neoclassical theory, is commonly attributed to the rotation damping effect of charge exchange, although a detailed comparison between charge-exchange damping theory and experiment is apparently unavailable. Such a comparison is attempted here in the context of recent TEXT experiments, which compare rotation rates, both poloidal and toroidal, in helium and hydrogen discharges. The helium discharges provide useful data because they are nearly free of ion-neutral charge exchange; they have been found to rotate toroidally in reasonable agreement with neoclassical predictions. The hydrogen experiments show much smaller toroidal motion as usual. The theoretical calculation uses the full charge-exchange operator and assumes plateau collisionality, roughly consistent with the experimental conditions. The authors calculate the ion flow as a function of v cx /v c , where v cx is the charge exchange rate and v c the Coulomb collision frequency. The results are in reasonable accord with the observations. 1 ref

  13. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Bohr, A.

    1976-01-01

    Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

  14. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  16. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  17. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  18. The rotation of galaxy clusters

    International Nuclear Information System (INIS)

    Tovmassian, H.M.

    2015-01-01

    The method for detection of the galaxy cluster rotation based on the study of distribution of member galaxies with velocities lower and higher of the cluster mean velocity over the cluster image is proposed. The search for rotation is made for flat clusters with a/b> 1.8 and BMI type clusters which are expected to be rotating. For comparison there were studied also round clusters and clusters of NBMI type, the second by brightness galaxy in which does not differ significantly from the cluster cD galaxy. Seventeen out of studied 65 clusters are found to be rotating. It was found that the detection rate is sufficiently high for flat clusters, over 60 per cent, and clusters of BMI type with dominant cD galaxy, ≈ 35 per cent. The obtained results show that clusters were formed from the huge primordial gas clouds and preserved the rotation of the primordial clouds, unless they did not have mergings with other clusters and groups of galaxies, in the result of which the rotation has been prevented

  19. Mid-term periodicities and heliospheric modulation of coronal index and solar flare index during solar cycles 22-23

    Science.gov (United States)

    Singh, Prithvi Raj; Saxena, A. K.; Tiwari, C. M.

    2018-04-01

    We applied fast Fourier transform techniques and Morlet wavelet transform on the time series data of coronal index, solar flare index, and galactic cosmic ray, for the period 1986-2008, in order to investigate the long- and mid-term periodicities including the Rieger ({˜ }130 to {˜ }190 days), quasi-period ({˜ }200 to {˜ }374 days), and quasi-biennial periodicities ({˜ }1.20 to {˜ }3.27 years) during the combined solar cycles 22-23. We emphasize the fact that a lesser number of periodicities are found in the range of low frequencies, while the higher frequencies show a greater number of periodicities. The rotation rates at the base of convection zone have periods for coronal index of {˜ }1.43 years and for solar flare index of {˜ }1.41 year, and galactic cosmic ray, {˜ }1.35 year, during combined solar cycles 22-23. In relation to these two solar parameters (coronal index and solar flare index), for the solar cycles 22-23, we found that galactic cosmic ray modulation at mid cut-off rigidity (Rc = 2.43GV) is anti-correlated with time-lag of few months.

  20. The solar neutrino problem

    International Nuclear Information System (INIS)

    Bahcall, J.N.

    1986-01-01

    The observed capture rate for solar neutrinos in the /sup 37/Cl detector is lower than the predicted capture rate. This discrepancy between theory and observation is known as the 'solar neutrino problem.' The author reviews the basic elements in this problem: the detector efficiency, the theory of stellar (solar) evolution, the nuclear physics of energy generation, and the uncertainties in the predictions. He also answers the questions of: So What? and What Next?

  1. Long-Term Variability of the Sun in the Context of Solar-Analog Stars

    Science.gov (United States)

    Egeland, Ricky

    2018-06-01

    The Sun is the best observed object in astrophysics, but despite this distinction the nature of its well-ordered generation of magnetic field in 11-year activity cycles remains a mystery. In this work, we place the solar cycle in a broader context by examining the long-term variability of solar analog stars within 5% of the solar effective temperature, but varied in rotation rate and metallicity. Emission in the Fraunhofer H & K line cores from singly-ionized calcium in the lower chromosphere is due to magnetic heating, and is a proven proxy for magnetic flux on the Sun. We use Ca H & K observations from the Mount Wilson Observatory HK project, the Lowell Observatory Solar Stellar Spectrograph, and other sources to construct composite activity time series of over 100 years in length for the Sun and up to 50 years for 26 nearby solar analogs. Archival Ca H & K observations of reflected sunlight from the Moon using the Mount Wilson instrument allow us to properly calibrate the solar time series to the S-index scale used in stellar studies. We find the mean solar S-index to be 5–9% lower than previously estimated, and the amplitude of activity to be small compared to active stars in our sample. A detailed look at the young solar analog HD 30495, which rotates 2.3 times faster than the Sun, reveals a large amplitude ~12-year activity cycle and an intermittent short-period variation of 1.7 years, comparable to the solar variability time scales despite its faster rotation. Finally, time series analyses of the solar analog ensemble and a quantitative analysis of results from the literature indicate that truly Sun-like cyclic variability is rare, and that the amplitude of activity over both long and short timescales is linearly proportional to the mean activity. We conclude that the physical conditions conducive to a quasi-periodic magnetic activity cycle like the Sun’s are rare in stars of approximately the solar mass, and that the proper conditions may be restricted

  2. High rates of solar radiation - an important natural stress factor of the photosynthetic activity of mountainous norway spruce stands

    International Nuclear Information System (INIS)

    Sprtova, M.; Marek, M.V.

    1996-01-01

    Photosynthetic activity can be regarded as the basis of biomass productivity and vitality of forest trees, respectively. Moreover, this activity is under the strong influence of environment. Excess of photosynthetically active radiation (PhAR) can be a harmful factor of environment which is the reason of photoinhibition. Photoinhibition is demonstrated by a decrease of photosynthetic rate. An analysis of the influence of PhAR excess on function of the assimilatory apparatus of Norway spruce during summer days was done. The strong influence of PhAR excess on values of parameters of photosynthesis reflecting changes in the level of quanta capture and electron transport chain was observed. The comprehensive description of the method of chlorophyll a is given. Excess of PhAR caused rapid changes of assimilatory apparatus function and thus this PhAR excess can be regarded as a significant stress of productional activity of Norway spruce stands under field conditions

  3. Rotationally invariant correlation filtering

    International Nuclear Information System (INIS)

    Schils, G.F.; Sweeney, D.W.

    1985-01-01

    A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

  4. Atmospheric acceleration and Earth-expansion deceleration of the Earth rotation

    Directory of Open Access Journals (Sweden)

    Wenbin Shen

    2017-11-01

    Full Text Available Previous studies suggest that tidal friction gives rise to the secular deceleration of the Earth rotation by a quantity of about 2.25 ms/cy. Here we just consider additional contributions to the secular Earth rotation deceleration. Atmospheric solar semi-diurnal tide has a small amplitude and certain amount of phase lead. This periodic global air-mass excess distribution exerts a quasi-constant torque to accelerate the Earth's spin rotation. Using an updated atmospheric tide model, we re-estimate the amounts of this atmospheric acceleration torque and corresponding energy input, of which the associated change rate in LOD (length of day is −0.1 ms/cy. In another aspect, evidences from space-geodesy and sea level rise observations suggest that Earth expands at a rate of 0.35 mm/yr in recent decades, which gives rise to the increase of LOD at rate of 1.0 ms/cy. Hence, if the previous estimate due to the tidal friction is correct, the secular Earth rotation deceleration due to tidal friction and Earth expansion should be 3.15 ms/cy.

  5. The solar Lithium problem: is the explanation due solely to mixing or also to the e-capture decay rate of 7Be?

    Science.gov (United States)

    Vescovi, Diego; Busso, Maurizio; Palmerini, Sara; Trippella, Oscar

    2018-01-01

    The nucleosynthesis of 7Li is one of the most crucial problems in nuclear as- trophysics, as its observations in several sites are hard to be explained. Concerning the Sun, the most common interpretations of the low Li abundance invoke either burning in early stages or non-convective mixing below the envelope. Here we apply a diffusive mechanism of mixing, together with a recent estimate of the rate for e-captures on 7Be, to establish whether the solar Li destruction should be attributed to purely pre-Main Se- quence (MS) nuclear processes or if the coupling of mixing and nucleosynthesis on the MS can account for it. Our preliminary results indicate that, whether Li survives the pre- MS phase, the changes of the 7Be e--capture rate do not affect its production/destruction. The low Li abundance should then depend only on diffusion processes from the bottom of the convective envelope to the lowerlying tachocline zone. We suggest that, if diffusive processes occurred over the age of the Sun, they required diffusive mass transfers of a few 10-13 M⊙/yr to explain the Li drop. This is a high estimate: future works will tell us if it is realistic or not. In this second case, pre-MS burning would remain the only alternative.

  6. On generating counter-rotating streamwise vortices

    KAUST Repository

    Winoto, S H

    2015-09-23

    Counter-rotating streamwise vortices are known to enhance the heat transfer rate from a surface and also to improve the aerodynamic performance of an aerofoil. In this paper, some methods to generate such counter-rotating vortices using different methods or physical conditions will be briefly considered and discussed.

  7. On generating counter-rotating streamwise vortices

    KAUST Repository

    Winoto, S H; Mitsudharmadi, Hatsari; Budiman, A C; Hasheminejad, S M; Nadesan, T; Tandiono; Low, H T; Lee, T S

    2015-01-01

    Counter-rotating streamwise vortices are known to enhance the heat transfer rate from a surface and also to improve the aerodynamic performance of an aerofoil. In this paper, some methods to generate such counter-rotating vortices using different methods or physical conditions will be briefly considered and discussed.

  8. Differential Rotation via Tracking of Coronal Bright Points.

    Science.gov (United States)

    McAteer, James; Boucheron, Laura E.; Osorno, Marcy

    2016-05-01

    The accurate computation of solar differential rotation is important both as a constraint for, and evidence towards, support of models of the solar dynamo. As such, the use of Xray and Extreme Ultraviolet bright points to elucidate differential rotation has been studied in recent years. In this work, we propose the automated detection and tracking of coronal bright points (CBPs) in a large set of SDO data for re-evaluation of solar differential rotation and comparison to other results. The big data aspects, and high cadence, of SDO data mitigate a few issues common to detection and tracking of objects in image sequences and allow us to focus on the use of CBPs to determine differential rotation. The high cadence of the data allows to disambiguate individual CBPs between subsequent images by allowing for significant spatial overlap, i.e., by the fact that the CBPs will rotate a short distance relative to their size. The significant spatial overlap minimizes the effects of incorrectly detected CBPs by reducing the occurrence of outlier values of differential rotation. The big data aspects of the data allows to be more conservative in our detection of CBPs (i.e., to err on the side of missing CBPs rather than detecting extraneous CBPs) while still maintaining statistically larger populations over which to study characteristics. The ability to compute solar differential rotation through the automated detection and tracking of a large population of CBPs will allow for further analyses such as the N-S asymmetry of differential rotation, variation of differential rotation over the solar cycle, and a detailed study of the magnetic flux underlying the CBPs.

  9. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  10. From Newton's bucket to rotating polygons

    DEFF Research Database (Denmark)

    Bach, B.; Linnartz, E. C.; Vested, Malene Louise Hovgaard

    2014-01-01

    We present an experimental study of 'polygons' forming on the free surface of a swirling water flow in a partially filled cylindrical container. In our set-up, we rotate the bottom plate and the cylinder wall with separate motors. We thereby vary rotation rate and shear strength independently...... and move from a rigidly rotating 'Newton's bucket' flow to one where bottom and cylinder wall are rotating oppositely and the surface is strongly turbulent but flat on average. Between those two extremes, we find polygonal states for which the rotational symmetry is spontaneously broken. We investigate...... the phase diagram spanned by the two rotational frequencies at a given water filling height and find polygons in a regime, where the two frequencies are sufficiently different and, predominantly, when they have opposite signs. In addition to the extension of the family of polygons found with the stationary...

  11. Polygons on a rotating fluid surface.

    Science.gov (United States)

    Jansson, Thomas R N; Haspang, Martin P; Jensen, Kåre H; Hersen, Pascal; Bohr, Tomas

    2006-05-05

    We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating internal waves in a similar setup was observed for much lower rotation rates, where the free surface remains essentially flat [J. M. Lopez, J. Fluid Mech. 502, 99 (2004). We speculate that the instability is caused by the strong azimuthal shear due to the stationary walls and that it is triggered by minute wobbling of the rotating plate.

  12. Solar energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role solar energy may have in the energy future of the US. The topics discussed in the chapter include the solar resource, solar architecture including passive solar design and solar collectors, solar-thermal concentrating systems including parabolic troughs and dishes and central receivers, photovoltaic cells including photovoltaic systems for home use, and environmental, health and safety issues

  13. Solar Probe Plus

    Science.gov (United States)

    Szabo, Adam

    2011-01-01

    The NASA Solar Probe Plus mission is planned to be launched in 2018 to study the upper solar corona with both.in-situ and remote sensing instrumentation. The mission will utilize 6 Venus gravity assist maneuver to gradually lower its perihelion to 9.5 Rs below the expected Alfven pOint to study the sub-alfvenic solar wind that is still at least partially co-rotates with the Sun. The detailed science objectives of this mission will be discussed. SPP will have a strong synergy with The ESA/NASA Solar orbiter mission to be launched a year ahead. Both missions will focus on the inner heliosphere and will have complimentary instrumentations. Strategies to exploit this synergy will be also presented.

  14. Solar thermal barometer

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    After the bad year of 2002, the european solar thermal market returned to double-digit growth rate in 2003: 22%. Nevertheless, the sector still has not recovered the growth rate it had in the early 2000 and European Commission targets are still far from being reached. This paper presents the thermal solar industry barometer. Data on the evolution of annually installed surfaces in the european union since 1993, the cumulated capacity of thermal collectors installed in the European Union, the estimation of the annual energy production associated to european solar thermal capacities and the main companies of the European Union thermal solar sector are presented and discussed. (A.L.B.)

  15. Hour of the brave. While the prices of turnkey solar power plants are getting lower, there is still uncertainty about reimbursement rates; Die Stunde der Mutigen. Die Preise fuer schluesselfertige Solarstromanlagen sinken, die Verguetungshoehe bleibt ungewiss

    Energy Technology Data Exchange (ETDEWEB)

    Krause, Matthias B.

    2012-07-15

    More than two months of uncertainty about reimbursement rates for solar power have left their mark in Germany. Customers are confused, demand is waning, and prices have decreased again as a new market survey shows. Manufacturers and fitters try to react by various different strategies.

  16. 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

  17. Rotating reactors : a review

    NARCIS (Netherlands)

    Visscher, F.; Schaaf, van der J.; Nijhuis, T.A.; Schouten, J.C.

    2013-01-01

    This review-perspective paper describes the current state-of-the-art in the field of rotating reactors. The paper has a focus on rotating reactor technology with applications at lab scale, pilot scale and industrial scale. Rotating reactors are classified and discussed according to their geometry:

  18. Rotation of a Moonless Earth

    Science.gov (United States)

    Lissauer, Jack J.; Barnes, Jason W.; Chambers, John E.

    2013-01-01

    We numerically explore the obliquity (axial tilt) variations of a hypothetical moonless Earth. Previous work has shown that the Earth's Moon stabilizes Earth's obliquity such that it remains within a narrow range, between 22.1 deg and 24.5 deg. Without lunar influence, a frequency-map analysis by Laskar et al. showed that the obliquity could vary between 0 deg. and 85 deg. This has left an impression in the astrobiology community that a large moon is necessary to maintain a habitable climate on an Earth-like planet. Using a modified version of the orbital integrator mercury, we calculate the obliquity evolution for moonless Earths with various initial conditions for up to 4 Gyr. We find that while obliquity varies significantly more than that of the actual Earth over 100,000 year timescales, the obliquity remains within a constrained range, typically 20-25 deg. in extent, for timescales of hundreds of millions of years. None of our Solar System integrations in which planetary orbits behave in a typical manner show obliquity accessing more than 65% of the full range allowed by frequency-map analysis. The obliquities of moonless Earths that rotate in the retrograde direction are more stable than those of pro-grade rotators. The total obliquity range explored for moonless Earths with rotation periods shorter than 12 h is much less than that for slower-rotating moonless Earths. A large moon thus does not seem to be needed to stabilize the obliquity of an Earth-like planet on timescales relevant to the development of advanced life.

  19. Rotating Stars in Relativity

    Directory of Open Access Journals (Sweden)

    Stergioulas Nikolaos

    2003-01-01

    Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.

  20. Towards the automatic detection and analysis of sunspot rotation

    Science.gov (United States)

    Brown, Daniel S.; Walker, Andrew P.

    2016-10-01

    Torsional rotation of sunspots have been noted by many authors over the past century. Sunspots have been observed to rotate up to the order of 200 degrees over 8-10 days, and these have often been linked with eruptive behaviour such as solar flares and coronal mass ejections. However, most studies in the literature are case studies or small-number studies which suffer from selection bias. In order to better understand sunspot rotation and its impact on the corona, unbiased large-sample statistical studies are required (including both rotating and non-rotating sunspots). While this can be done manually, a better approach is to automate the detection and analysis of rotating sunspots using robust methods with well characterised uncertainties. The SDO/HMI instrument provide long-duration, high-resolution and high-cadence continuum observations suitable for extracting a large number of examples of rotating sunspots. This presentation will outline the analysis of SDI/HMI data to determine the rotation (and non-rotation) profiles of sunspots for the complete duration of their transit across the solar disk, along with how this can be extended to automatically identify sunspots and initiate their analysis.

  1. Some properties of the dynamics of the solar convective zone and their consequences on the activity cycle

    International Nuclear Information System (INIS)

    Ribes, E.

    1986-01-01

    A large-scale circulation pattern has been detected in the solar convective zone, for the first time. Tracers used to probe the convective layers are newly-born sunspots and long-lived Hsub(α) filaments. The coincidence of the zonal meridional circulation with the magnetic pattern drawn by the Hsub(α) filaments suggests that we are looking at rotating rolls. The direction of rotation is associated with the magnetic polarity. Another result concerns the rotational rate of the deep convective layers. Young spots seem to rotate more rigidly, in contrast with older spots which exhibit a differential rotation similar to the surface rotation. However, the rotational rate exhibits a large dispersion, partly due to young spots located at the site of converging of diverging rolls. This is the consequence of the Coriolis force which decelerates or accelerates the plasma. These results shed a completely new light on problems dealing with the differential rotation, the transport of angular momentum and the dynamo action [fr

  2. On Averaging Rotations

    DEFF Research Database (Denmark)

    Gramkow, Claus

    1999-01-01

    In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belo...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion......In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

  3. Core rotational dynamics and geological events

    Science.gov (United States)

    Greff-Lefftz; Legros

    1999-11-26

    A study of Earth's fluid core oscillations induced by lunar-solar tidal forces, together with tidal secular deceleration of Earth's axial rotation, shows that the rotational eigenfrequency of the fluid core and some solar tidal waves were in resonance around 3.0 x 10(9), 1.8 x 10(9), and 3 x 10(8) years ago. The associated viscomagnetic frictional power at the core boundaries may be converted into heat and would destabilize the D" thermal layer, leading to the generation of deep-mantle plumes, and would also increase the temperature at the fluid core boundaries, perturbing the core dynamo process. Such phenomena could account for large-scale episodes of continental crust formation, the generation of flood basalts, and abrupt changes in geomagnetic reversal frequency.

  4. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  5. Quantitative rotating frame relaxometry methods in MRI.

    Science.gov (United States)

    Gilani, Irtiza Ali; Sepponen, Raimo

    2016-06-01

    Macromolecular degeneration and biochemical changes in tissue can be quantified using rotating frame relaxometry in MRI. It has been shown in several studies that the rotating frame longitudinal relaxation rate constant (R1ρ ) and the rotating frame transverse relaxation rate constant (R2ρ ) are sensitive biomarkers of phenomena at the cellular level. In this comprehensive review, existing MRI methods for probing the biophysical mechanisms that affect the rotating frame relaxation rates of the tissue (i.e. R1ρ and R2ρ ) are presented. Long acquisition times and high radiofrequency (RF) energy deposition into tissue during the process of spin-locking in rotating frame relaxometry are the major barriers to the establishment of these relaxation contrasts at high magnetic fields. Therefore, clinical applications of R1ρ and R2ρ MRI using on- or off-resonance RF excitation methods remain challenging. Accordingly, this review describes the theoretical and experimental approaches to the design of hard RF pulse cluster- and adiabatic RF pulse-based excitation schemes for accurate and precise measurements of R1ρ and R2ρ . The merits and drawbacks of different MRI acquisition strategies for quantitative relaxation rate measurement in the rotating frame regime are reviewed. In addition, this review summarizes current clinical applications of rotating frame MRI sequences. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. The lithium-rotation connection in the 125 Myr-old Pleiades cluster

    Science.gov (United States)

    Bouvier, J.; Barrado, D.; Moraux, E.; Stauffer, J.; Rebull, L.; Hillenbrand, L.; Bayo, A.; Boisse, I.; Bouy, H.; DiFolco, E.; Lillo-Box, J.; Calderón, M. Morales

    2018-06-01

    Context. The evolution of lithium abundance over a star's lifetime is indicative of transport processes operating in the stellar interior. Aims: We revisit the relationship between lithium content and rotation rate previously reported for cool dwarfs in the Pleiades cluster. Methods: We derive new LiI 670.8 nm equivalent width measurements from high-resolution spectra obtained for low-mass Pleiades members. We combine these new measurements with previously published ones, and use the Kepler K2 rotational periods recently derived for Pleiades cool dwarfs to investigate the lithium-rotation connection in this 125 Myr-old cluster. Results: The new data confirm the correlation between lithium equivalent width and stellar spin rate for a sample of 51 early K-type members of the cluster, where fast rotating stars are systematically lithium-rich compared to slowly rotating ones. The correlation is valid for all stars over the (J-Ks) color range 0.50-0.70 mag, corresponding to a mass range from about 0.75 to 0.90 M⊙, and may extend down to lower masses. Conclusions: We argue that the dispersion in lithium equivalent widths observed for cool dwarfs in the Pleiades cluster reflects an intrinsic scatter in lithium abundances, and suggest that the physical origin of the lithium dispersion pattern is to be found in the pre-main sequence rotational history of solar-type stars. Based on observations made at Observatoire de Haute Provence (CNRS), France, at the Nordic Optical Telescope (IAC), Spain, and at the W. M. Keck Observatory, Hawaii, USA.Full Table B.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/613/A63

  7. Rotational Modulation and Activity Cycles at Rotational Extremes: 25 yrs of NURO Photometry for HII 1883

    Science.gov (United States)

    Milingo, Jackie; Saar, Steven; Marschall, Laurence

    2018-01-01

    We present a 25 yr compilation of V-band differential photometry for the Pleiades K dwarf HII 1883 (V660 Tau). HII 1883 has a rotational period of ~ 0.24 d and displays significant rotational modulation due to non-uniform surface brightness or "starspots". Preliminary work yields a cycle period of ~ 9 yrs and rotational shear (ΔP_rot/) considerably less than solar. HII 1883 is one of the fastest rotating single stars with a known cycle. With additional data available we compare newly determined P_cyc and ΔP_rot/ values with those of other stars, putting HII 1883 into the broader context of dynamo properties in single cool dwarfs.

  8. Equations for solar tracking.

    Science.gov (United States)

    Merlaud, Alexis; De Mazière, Martine; Hermans, Christian; Cornet, Alain

    2012-01-01

    Direct sunlight absorption by trace gases can be used to quantify them and investigate atmospheric chemistry. In such experiments, the main optical apparatus is often a grating or a Fourier transform spectrometer. A solar tracker based on motorized rotating mirrors is commonly used to direct the light along the spectrometer axis, correcting for the apparent rotation of the Sun. Calculating the Sun azimuth and altitude for a given time and location can be achieved with high accuracy but different sources of angular offsets appear in practice when positioning the mirrors. A feedback on the motors, using a light position sensor close to the spectrometer, is almost always needed. This paper aims to gather the main geometrical formulas necessary for the use of a widely used kind of solar tracker, based on two 45° mirrors in altazimuthal set-up with a light sensor on the spectrometer, and to illustrate them with a tracker developed by our group for atmospheric research.

  9. THE ROTATION PERIOD OF HD-77581 (VELA X-1)

    NARCIS (Netherlands)

    ZUIDERWIJK, EJ

    The rotation period of HD 77581, supergiant primary in the X-ray binary Vela X-1, is determined from an analysis of selected absorption line profiles. The rotation rate determined from He I line profiles is 0.67 +/- 0.04 times that of the binary angular velocity, corresponding to a rotation velocity

  10. Changes in the earth's rotation by tectonics : gravito-elastodynamics

    NARCIS (Netherlands)

    Vermeersen, L.L.A.

    1993-01-01

    The rotation of the Earth is not regular. It changes on virtually every timescale we know in both position of the rotation axis and rotation rate. Even in our daily lives we sometimes experience the consequences of such changes, such as the second that is subtracted or added to clocks at the

  11. Molded polymer solar water heater

    Science.gov (United States)

    Bourne, Richard C.; Lee, Brian E.

    2004-11-09

    A solar water heater has a rotationally-molded water box and a glazing subassembly disposed over the water box that enhances solar gain and provides an insulating air space between the outside environment and the water box. When used with a pressurized water system, an internal heat exchanger is integrally molded within the water box. Mounting and connection hardware is included to provide a rapid and secure method of installation.

  12. Rotations with Rodrigues' vector

    International Nuclear Information System (INIS)

    Pina, E

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

  13. On Averaging Rotations

    DEFF Research Database (Denmark)

    Gramkow, Claus

    2001-01-01

    In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong ...... approximations to the Riemannian metric, and that the subsequent corrections are inherent in the least squares estimation.......In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

  14. Solar energy storage

    CERN Document Server

    Sorensen, Bent

    2015-01-01

    While solar is the fastest-growing energy source in the world, key concerns around solar power's inherent variability threaten to de-rail that scale-up . Currently, integration of intermittent solar resources into the grid creates added complication to load management, leading some utilities to reject it altogether, while other operators may penalize the producers via rate increases or force solar developers to include storage devices on-site to smooth out power delivery at the point of production. However these efforts at mitigation unfold, it is increasingly clear to parties on all sides th

  15. Physics of rotation: problems and challenges

    Science.gov (United States)

    Maeder, Andre; Meynet, Georges

    2015-01-01

    We examine some debated points in current discussions about rotating stars: the shape, the gravity darkening, the critical velocities, the mass loss rates, the hydrodynamical instabilities, the internal mixing and N-enrichments. The study of rotational mixing requires high quality data and careful analysis. From recent studies where such conditions are fulfilled, rotational mixing is well confirmed. Magnetic coupling with stellar winds may produce an apparent contradiction, i.e. stars with a low rotation and a high N-enrichment. We point out that it rather confirms the large role of shears in differentially rotating stars for the transport processes. New models of interacting binaries also show how shears and mixing may be enhanced in close binaries which are either spun up or down by tidal interactions.

  16. Influence of toroidal rotation on tearing modes

    Science.gov (United States)

    Cai, Huishan; Cao, Jintao; Li, Ding

    2017-10-01

    Tearing modes stability analysis including toroidal rotation is studied. It is found that rotation affects the stability of tearing modes mainly through the interaction with resistive inner region of tearing mode. The coupling of magnetic curvature with centrifugal force and Coriolis force provides a perturbed perpendicular current, and a return parallel current is induced to affect the stability of tearing modes. Toroidal rotation plays a stable role, which depends on the magnitude of Mach number and adiabatic index Γ, and is independent on the direction of toroidal rotation. For Γ >1, the scaling of growth rate is changed for typical Mach number in present tokamaks. For Γ = 1 , the scaling keeps unchanged, and the effect of toroidal rotation is much less significant, compared with that for Γ >1. National Magnetic Confinement Fusion Science Program and National Science Foundation of China under Grants No. 2014GB106004, No. 2013GB111000, No. 11375189, No. 11075161 and No. 11275260, and Youth Innovation Promotion Association CAS.

  17. QUASI-BIENNIAL OSCILLATIONS IN THE SOLAR TACHOCLINE CAUSED BY MAGNETIC ROSSBY WAVE INSTABILITIES

    International Nuclear Information System (INIS)

    Zaqarashvili, Teimuraz V.; Carbonell, Marc; Oliver, Ramon; Ballester, Jose Luis

    2010-01-01

    Quasi-biennial oscillations (QBOs) are frequently observed in solar activity indices. However, no clear physical mechanism for the observed variations has been suggested so far. Here, we study the stability of magnetic Rossby waves in the solar tachocline using the shallow water magnetohydrodynamic approximation. Our analysis shows that the combination of typical differential rotation and a toroidal magnetic field with a strength of ≥10 5 G triggers the instability of the m = 1 magnetic Rossby wave harmonic with a period of ∼2 years. This harmonic is antisymmetric with respect to the equator and its period (and growth rate) depends on the differential rotation parameters and magnetic field strength. The oscillations may cause a periodic magnetic flux emergence at the solar surface and consequently may lead to the observed QBO in solar activity features. The period of QBOs may change throughout a cycle, and from cycle to cycle, due to variations of the mean magnetic field and differential rotation in the tachocline.

  18. Solar Features - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A solar flare is a short-lived sudden increase in the intensity of radiation emitted in the neighborhood of sunspots. For many years it was best monitored in the...

  19. Developing an Asteroid Rotational Theory

    Science.gov (United States)

    Geis, Gena; Williams, Miguel; Linder, Tyler; Pakey, Donald

    2018-01-01

    The goal of this project is to develop a theoretical asteroid rotational theory from first principles. Starting at first principles provides a firm foundation for computer simulations which can be used to analyze multiple variables at once such as size, rotation period, tensile strength, and density. The initial theory will be presented along with early models of applying the theory to the asteroid population. Early results confirm previous work by Pravec et al. (2002) that show the majority of the asteroids larger than 200m have negligible tensile strength and have spin rates close to their critical breakup point. Additionally, results show that an object with zero tensile strength has a maximum rotational rate determined by the object’s density, not size. Therefore, an iron asteroid with a density of 8000 kg/m^3 would have a minimum spin period of 1.16h if the only forces were gravitational and centrifugal. The short-term goal is to include material forces in the simulations to determine what tensile strength will allow the high spin rates of asteroids smaller than 150m.

  20. Observational investigation of the solar oblateness

    International Nuclear Information System (INIS)

    Stebbins, R.T.

    1975-01-01

    The solar oblateness provides important information for solar physics and experimental relativity. After the solar neutrino flux, the sun's shape is the most revealing probe of the solar interior. Rapidly rotating interiors suggested to explain the solar neutrino paradox produce sizeable oblatenesses. Certain types of surface phenomena can also be investigated with precision diameter measurements. The relativistic advance of Mercury's perihelion has long been the principal experimental support for Einstein's theory of general relativity. Recent measurements of the solar oblateness have suggested that the relativistic advance is smaller than originally thought due to a contribution from a solar mass quadrupole moment. This interpretation of the perihelion advance would shift the experimental support to the scalar-tensor theory of gravitation. A debate over the interpretation of the oblateness measurements has resulted. In light of these circumstances, solar oblateness observations have been attempted. Improved experimental techniques have been devised, including a daytime astrometric telescope and an explicit definition of the sun's edge. Observations reveal a time varying excess equatorial brightness, that is, a variation in the limb darkening function between equator and pole, which would preclude accurate interpretation of previous solar oblateness measurements. This vindicates the alternate interpretations of other solar oblateness measurements. From these results, it can be concluded that the Mercury perihelion evidence firmly supports Einstein's General Theory of Relativity, the solar interiors cannot be rotating fast enough to account for the low solar neutrino flux, and a time varying excess equatorial brightness exists

  1. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  2. Variations of Solar Non-axisymmetric Activity

    Science.gov (United States)

    Gyenge, N.; Baranyi, T.; Ludmány, A.

    The temporal behaviour of solar active longitudes has been examined by using two sunspot catalogues, the Greenwich Photoheliographic Results (GPR) and the Debrecen Photoheliographic Data (DPD). The time-longitude diagrams of the activity distribution reveal the preferred longitudinal zones and their migration with respect to the Carrington frame. The migration paths outline a set of patterns in which the activity zone has alternating prograde/retrograde angular velocities with respect to the Carrington rotation rate. The time profiles of these variations can be described by a set of successive parabolae. Two similar migration paths have been selected from these datasets, one northern path during cycles 21 - 22 and one southern path during cycles 13 - 14, for closer examination and comparison of their dynamical behaviours. The rates of sunspot emergence exhibited in both migration paths similar periodicities, close to 1.3 years. This behaviour may imply that the active longitude is connected to the bottom of convection zone.

  3. The spatial rotator

    DEFF Research Database (Denmark)

    Rasmusson, Allan; Hahn, Ute; Larsen, Jytte Overgaard

    2013-01-01

    This paper presents a new local volume estimator, the spatial rotator, which is based on measurements on a virtual 3D probe, using computer assisted microscopy. The basic design of the probe builds upon the rotator principle which requires only a few manual intersection markings, thus making...

  4. Superconducting rotating machines

    International Nuclear Information System (INIS)

    Smith, J.L. Jr.; Kirtley, J.L. Jr.; Thullen, P.

    1975-01-01

    The opportunities and limitations of the applications of superconductors in rotating electric machines are given. The relevant properties of superconductors and the fundamental requirements for rotating electric machines are discussed. The current state-of-the-art of superconducting machines is reviewed. Key problems, future developments and the long range potential of superconducting machines are assessed

  5. Fundamental Relativistic Rotator

    International Nuclear Information System (INIS)

    Staruszkiewicz, A.

    2008-01-01

    Professor Jan Weyssenhoff was Myron Mathisson's sponsor and collaborator. He introduced a class of objects known in Cracow as '' kreciolki Weyssenhoffa '', '' Weyssenhoff's rotating little beasts ''. The Author describes a particularly simple object from this class. The relativistic rotator described in the paper is such that its both Casimir invariants are parameters rather than constants of motion. (author)

  6. SMAP Faraday Rotation

    Science.gov (United States)

    Le Vine, David

    2016-01-01

    Faraday rotation is a change in the polarization as signal propagates through the ionosphere. At L-band it is necessary to correct for this change and measurements are made on the spacecraft of the rotation angle. These figures show that there is good agreement between the SMAP measurements (blue) and predictions based on models (red).

  7. The rotating universe

    International Nuclear Information System (INIS)

    Ruben, G.; Treder, H.J.

    1987-01-01

    For a long time the question whether the universe rotates or not is discussed. Aspects of Huygens, Newton, Mach and other important historical scientists in this field are reported. The investigations of the mathematician Kurt Groedel in order to prove the rotation of the universe are illustrated. Kurt Groedel has shown that Einstein's gravitational equations of general relativity theory and the cosmological postulate of global homogeneity of cosmic matter (that is the Copernical principle) are not contradictionary to a rotating universe. Abberation measurements, position determination by means of radiointerferometry and methods for the determination of the rotation of the universe from the isotropy of the background radiation are presented. From these experiments it can be concluded that the universe seems not to rotate as already Einstein expected

  8. Rotation sensor switch

    International Nuclear Information System (INIS)

    Sevec, J.B.

    1978-01-01

    A protective device to provide a warning if a piece of rotating machinery slows or stops is comprised of a pair of hinged weights disposed to rotate on a rotating shaft of the equipment. When the equipment is rotating, the weights remain in a plane essentially perpendicular to the shaft and constitute part of an electrical circuit that is open. When the shaft slows or stops, the weights are attracted to a pair of concentric electrically conducting disks disposed in a plane perpendicular to the shaft and parallel to the plane of the weights when rotating. A disk magnet attracts the weights to the electrically conducting plates and maintains the electrical contact at the plates to complete an electrical circuit that can then provide an alarm signal

  9. Rotating stars in relativity.

    Science.gov (United States)

    Paschalidis, Vasileios; Stergioulas, Nikolaos

    2017-01-01

    Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on equilibrium properties and on nonaxisymmetric oscillations and instabilities in f -modes and r -modes have been updated. Several new sections have been added on equilibria in modified theories of gravity, approximate universal relationships, the one-arm spiral instability, on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity including both hydrodynamic and magnetohydrodynamic studies of these objects.

  10. Enhancing Rotational Diffusion Using Oscillatory Shear

    KAUST Repository

    Leahy, Brian D.

    2013-05-29

    Taylor dispersion - shear-induced enhancement of translational diffusion - is an important phenomenon with applications ranging from pharmacology to geology. Through experiments and simulations, we show that rotational diffusion is also enhanced for anisotropic particles in oscillatory shear. This enhancement arises from variations in the particle\\'s rotation (Jeffery orbit) and depends on the strain amplitude, rate, and particle aspect ratio in a manner that is distinct from the translational diffusion. This separate tunability of translational and rotational diffusion opens the door to new techniques for controlling positions and orientations of suspended anisotropic colloids. © 2013 American Physical Society.

  11. Critical fields and growth rates of the Tayler instability as probed by a columnar gallium experiment

    OpenAIRE

    Ruediger, Guenther; Gellert, Marcus; Schultz, Manfred; Strassmeier, Klaus G.; Stefani, Frank; Gundrum, Thomas; Seilmayer, Martin; Gerbeth, Gunter

    2012-01-01

    Many astrophysical phenomena (such as the slow rotation of neutron stars or the rigid rotation of the solar core) can be explained by the action of the Tayler instability of toroidal magnetic fields in the radiative zones of stars. In order to place the theory of this instability on a safe fundament it has been realized in a laboratory experiment measuring the critical field strength, the growth rates as well as the shape of the supercritical modes. A strong electrical current flows through a...

  12. A theoretical study of rotatable renewable energy system for stratospheric airship

    International Nuclear Information System (INIS)

    Lv, Mingyun; Li, Jun; Zhu, Weiyu; Du, Huafei; Meng, Junhui; Sun, Kangwen

    2017-01-01

    Highlights: • A new rotatable renewable energy system is designed for stratospheric airship. • A theoretical model of optimal rotation angle and required area are studied. • The effects of latitude and date on output energy per day are investigated. • The advantages of the rotatable renewable energy system are studied. - Abstract: Renewable energy system is very critical for solving the energy problem of a long endurance stratospheric airship. Output performance of the traditional solar array fixed on the upper surface of the airship remains to be improved to reduce the area and weight of renewable energy system. Inspired by the solar tracking system and kirigami, a rotatable renewable energy system (mainly including solar array) is designed to improve the current status of the energy system. The advantages of the rotatable solar array are studied using a MATLAB computer program based on the theoretical model established in this paper. The improvements in output energy and required area of the solar array were compared between the traditional airship and improved one. Studies had shown that the rotatable renewable energy system made the total weight of energy system decreased by 1000 kg when the maximum design speed of the airship was greater than 22 m/s. The results demonstrate that the rotatable renewable energy system for the airship can be a good way to improve the output performance of solar array, and the conceptual design and theoretical model suggest a pathway towards solving the energy problem of a stratospheric airship.

  13. A parametric study of a solar calcinator using computational fluid dynamics

    International Nuclear Information System (INIS)

    Fidaros, D.K.; Baxevanou, C.A.; Vlachos, N.S.

    2007-01-01

    In this work a horizontal rotating solar calcinator is studied numerically using computational fluid dynamics. The specific solar reactor is a 10 kW model designed and used for efficiency studies. The numerical model is based on the solution of the Navier-Stokes equations for the gas flow, and on Lagrangean dynamics for the discrete particles. All necessary mathematical models were developed and incorporated into a computational fluid dynamics model with the influence of turbulence simulated by a two-equation (RNG k-ε) model. The efficiency of the reactor was calculated for different thermal inputs, feed rates, rotational speeds and particle diameters. The numerically computed degrees of calcination compared well with equivalent experimental results

  14. Internal differential rotation of the Sun: the P-modes frequency splitting in the measurements of brightness oscillations

    International Nuclear Information System (INIS)

    Didkovskij, L.V.

    1989-01-01

    a 12-DAY SERIES OF TWO-DIMNIONAL IMAGES OF SOLAR BRIGHTNESS OSCILLATIONS EIGENFREQUENCIES in the range of 6-32 degrees. The rotational frequency splitting of separate modes as a function of inner turn-points radius of acoustic waves is found. The results of the analysis shw fast rotation of the central region of the Sun and non-monotonous trend of angular rotation velocity varitions with radius of the boundary of solar core

  15. Geology and photometric variation of solar system bodies with minor atmospheres: implications for solid exoplanets.

    Science.gov (United States)

    Fujii, Yuka; Kimura, Jun; Dohm, James; Ohtake, Makiko

    2014-09-01

    A reasonable basis for future astronomical investigations of exoplanets lies in our best knowledge of the planets and satellites in the Solar System. Solar System bodies exhibit a wide variety of surface environments, even including potential habitable conditions beyond Earth, and it is essential to know how they can be characterized from outside the Solar System. In this study, we provide an overview of geological features of major Solar System solid bodies with minor atmospheres (i.e., the terrestrial Moon, Mercury, the Galilean moons, and Mars) that affect surface albedo at local to global scale, and we survey how they influence point-source photometry in the UV/visible/near IR (i.e., the reflection-dominant range). We simulate them based on recent mapping products and also compile observed light curves where available. We show a 5-50% peak-to-trough variation amplitude in one spin rotation associated with various geological processes including heterogeneous surface compositions due to igneous activities, interaction with surrounding energetic particles, and distribution of grained materials. Some indications of these processes are provided by the amplitude and wavelength dependence of variation in combinations of the time-averaged spectra. We also estimate the photometric precision needed to detect their spin rotation rates through periodogram analysis. Our survey illustrates realistic possibilities for inferring the detailed properties of solid exoplanets with future direct imaging observations. Key Words: Planetary environments-Planetary geology-Solar System-Extrasolar terrestrial planets.

  16. Solar neutrino

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, D [Tokyo Univ. (Japan). Coll. of General Education

    1975-01-01

    The measurement of solar neutrino was performed by using the reaction /sup 37/cl+..nu..sub(e)..-->../sup 37/Ar+e/sup -/ by Davis et al. The argon gas produced through the above mentioned reaction in a tank containing 610 ton of C/sub 2/Cl/sub 4/ was collected and measured. The rate of production of /sup 37/Ar was 0.13+-0.20/day, and the net production rate by the solar neutrino was 0.06+-0.20/day, being corrected for background. This value corresponds to 0.5+-1.0 SNU. Theoretical calculation with the model of spherically symmetric solar development gave an expected value of 5.6 SNU, which is in contradiction with the experimental value. Reason of this discrepancy was considered. The possibility of decay of neutrino to the other particles with weak interaction is very slight. Various models of the sun were investigated, but the results were still inconsistent with the experiment. The mixing of matters in the sun may cause the reduction of neutrino. If He gas comes to the center of the sun by mixing, the reaction, /sup 3/He+/sup 3/He, progresses excessively at the center, and it produces the expansion of the core of the sun. Then, the temperature drops and the neutrino is reduced. Various models which can explain the neutrino of less than ISNU have been presented. However, other theory says that the reduction of neutrino is not expected even if the mixing is considered. A problem concerning the mixing is whether the thermal instability which causes the mixing exists. (Kato, T.).

  17. Helicity--vorticity turbulent pumping of magnetic fields in the solar dynamo

    OpenAIRE

    Pipin, V. V.

    2012-01-01

    The interaction of helical convective motions and differential rotation in the solar convection zone results in turbulent drift of a large-scale magnetic field. We discuss the pumping mechanism and its impact on the solar dynamo.

  18. Solar Energy.

    Science.gov (United States)

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  19. Rotational instabilities in field reversed configurations

    International Nuclear Information System (INIS)

    Santiago, M.A.M.; Tsui, K.H.; Ponciano, B.M.B.; Sakanaka, P.H.

    1988-01-01

    The rotational instability (n = 2 toroidal mode) in field reversed configurations (FRC) using the ideal MHD equations in cylindrical geometry is studied. These equations are solved using a realistic densite profile, and the influence of some plasma parameters on the growth rate is analysed. The model shows good qualitative results. The growth rate increases rapidly as rotational frequency goes up and the mode m = 2 dominates over the m = 1 mode. With the variation of the density profile, it is observed that the growth rate decreases as the density dip at the center fills up. Calculated value ranges from 1/2 to 1/7 of the rotational frequency Ω whereas the measured value is around Ω/50. The developed analysis is valid for larger machines. The influence of the plasma resistivity on the mode stabilization is also analysed. The resistivity, which is the fundamental factor in the formation of compact torus, tends to decrease the growth rate. (author) [pt

  20. Dynamics of Tidally Locked, Ultrafast Rotating Atmospheres

    Science.gov (United States)

    Tan, Xianyu; Showman, Adam P.

    2017-10-01

    Tidally locked gas giants, which exhibit a novel regime of day-night thermal forcing and extreme stellar irradiation, are typically in several-day orbits, implying slow rotation and a modest role for rotation in the atmospheric circulation. Nevertheless, there exist a class of gas-giant, highly irradiated objects - brown dwarfs orbiting white dwarfs in extremely tight orbits - whose orbital and hence rotation periods are as short as 1-2 hours. Spitzer phase curves and other observations have already been obtained for this fascinating class of objects, which raise fundamental questions about the role of rotation in controlling the circulation. So far, most modeling studies have investigated rotation periods exceeding a day, as appropriate for typical hot Jupiters. In this work we investigate the dynamics of tidally locked atmospheres in shorter rotation periods down to about two hours. With increasing rotation rate (decreasing rotation period), we show that the width of the equatorial eastward jet decreases, consistent with the narrowing of wave-mean-flow interacting region due to decrease of the equatorial deformation radius. The eastward-shifted equatorial hot spot offset decreases accordingly, and the westward-shifted hot regions poleward of the equatorial jet associated with Rossby gyres become increasingly distinctive. At high latitudes, winds becomes weaker and more geostrophic. The day-night temperature contrast becomes larger due to the stronger influence of rotation. Our simulated atmospheres exhibit small-scale variability, presumably caused by shear instability. Unlike typical hot Jupiters, phase curves of fast-rotating models show an alignment of peak flux to secondary eclipse. Our results have important implications for phase curve observations of brown dwarfs orbiting white dwarfs in ultra tight orbits.

  1. Immobilization in External Rotation Versus Internal Rotation After Primary Anterior Shoulder Dislocation: A Meta-analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Whelan, Daniel B; Kletke, Stephanie N; Schemitsch, Geoffrey; Chahal, Jaskarndip

    2016-02-01

    The recurrence rate after primary anterior shoulder dislocation is high, especially in young, active individuals. Recent studies have suggested external rotation immobilization as a method to reduce the rate of recurrent shoulder dislocation in comparison to traditional sling immobilization. To assess and summarize evidence from randomized controlled trials on the effect of internal rotation versus external rotation immobilization on the rate of recurrence after primary anterior shoulder dislocation. Meta-analysis. PubMed, MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and abstracts from recent proceedings were searched for eligible studies. Two reviewers selected studies for inclusion, assessed methodological quality, and extracted data. Six randomized controlled trials (632 patients) were included in this review. Demographic and prognostic variables measured at baseline were similar in the pooled groups. The average age was 30.1 years in the pooled external rotation group and 30.3 years in the pooled internal rotation group. Two studies found that external rotation immobilization reduced the rate of recurrence after initial anterior shoulder dislocation compared with conventional internal rotation immobilization, whereas 4 studies failed to find a significant difference between the 2 groups. This meta-analysis suggested no overall significant difference in the rate of recurrence among patients treated with internal rotation versus external rotation immobilization (risk ratio, 0.69; 95% CI, 0.42-1.14; P = .15). There was no significant difference in the rate of compliance between internal and external rotation immobilization (P = .43). The Western Ontario Shoulder Instability Index scores were pooled across 3 studies, and there was no significant difference between the 2 groups (P = .54). Immobilization in external rotation is not significantly more effective in reducing the recurrence rate after primary anterior shoulder dislocation than

  2. Solar energy

    Science.gov (United States)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  3. Solar Combisystems

    DEFF Research Database (Denmark)

    Thür, Alexander

    2006-01-01

    This note first introduces what is a solar combisystem, the structure how a solar combisystem is build up and what are criteria’s to evaluate a solar combisystem concept. Further on the main components of a solar combisystem, the main characteristics and possible advantages and disadvantages...... compared to each other are described. It is not the goal of this note to explain the technical details how to design all components of a solar combisystem. This is done during other lectures of the solar course and in other basic courses as well. This note tries to explain how a solar combisystem...

  4. EVIDENCE FOR CLUSTER TO CLUSTER VARIATIONS IN LOW-MASS STELLAR ROTATIONAL EVOLUTION

    International Nuclear Information System (INIS)

    Coker, Carl T.; Pinsonneault, Marc; Terndrup, Donald M.

    2016-01-01

    The concordance model for angular momentum evolution postulates that star-forming regions and clusters are an evolutionary sequence that can be modeled with assumptions about protostar–disk coupling, angular momentum loss from magnetized winds that saturates in a mass-dependent fashion at high rotation rates, and core-envelope decoupling for solar analogs. We test this approach by combining established data with the large h Per data set from the MONITOR project and new low-mass Pleiades data. We confirm prior results that young low-mass stars can be used to test star–disk coupling and angular momentum loss independent of the treatment of internal angular momentum transport. For slow rotators, we confirm the need for star–disk interactions to evolve the ONC to older systems, using h Per (age 13 Myr) as our natural post-disk case. There is no evidence for extremely long-lived disks as an alternative to core-envelope decoupling. However, our wind models cannot evolve rapid rotators from h Per to older systems consistently, and we find that this result is robust with respect to the choice of angular momentum loss prescription. We outline two possible solutions: either there is cosmic variance in the distribution of stellar rotation rates in different clusters or there are substantially enhanced torques in low-mass rapid rotators. We favor the former explanation and discuss observational tests that could be used to distinguish them. If the distribution of initial conditions depends on environment, models that test parameters by assuming a universal underlying distribution of initial conditions will need to be re-evaluated.

  5. EVIDENCE FOR CLUSTER TO CLUSTER VARIATIONS IN LOW-MASS STELLAR ROTATIONAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Carl T.; Pinsonneault, Marc; Terndrup, Donald M., E-mail: coker@astronomy.ohio-state.edu, E-mail: pinsono@astronomy.ohio-state.edu, E-mail: terndrup@astronomy.ohio-state.edu [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)

    2016-12-10

    The concordance model for angular momentum evolution postulates that star-forming regions and clusters are an evolutionary sequence that can be modeled with assumptions about protostar–disk coupling, angular momentum loss from magnetized winds that saturates in a mass-dependent fashion at high rotation rates, and core-envelope decoupling for solar analogs. We test this approach by combining established data with the large h Per data set from the MONITOR project and new low-mass Pleiades data. We confirm prior results that young low-mass stars can be used to test star–disk coupling and angular momentum loss independent of the treatment of internal angular momentum transport. For slow rotators, we confirm the need for star–disk interactions to evolve the ONC to older systems, using h Per (age 13 Myr) as our natural post-disk case. There is no evidence for extremely long-lived disks as an alternative to core-envelope decoupling. However, our wind models cannot evolve rapid rotators from h Per to older systems consistently, and we find that this result is robust with respect to the choice of angular momentum loss prescription. We outline two possible solutions: either there is cosmic variance in the distribution of stellar rotation rates in different clusters or there are substantially enhanced torques in low-mass rapid rotators. We favor the former explanation and discuss observational tests that could be used to distinguish them. If the distribution of initial conditions depends on environment, models that test parameters by assuming a universal underlying distribution of initial conditions will need to be re-evaluated.

  6. Solar Systems

    Science.gov (United States)

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  7. Rotation, Stability and Transport

    Energy Technology Data Exchange (ETDEWEB)

    Connor, J. W.

    2007-07-01

    Tokamak plasmas can frequently exhibit high levels of rotation and rotation shear. This can usually be attributed to various sources: injection of momentum, e.g. through neutral beams, flows driven by plasma gradients or torques resulting from non-ambipolar particle loss; however, the source sometimes remains a mystery, such as the spontaneous rotation observed in Ohmic plasmas. The equilibrium rotation profile is given by the balance of these sources with transport and other losses; the edge boundary conditions can play an important role in determining this profile . Such plasma rotation, particularly sheared rotation, is predicted theoretically to have a significant influence on plasma behaviour. In the first place, sonic flows can significantly affect tokamak equilibria and neoclassical transport losses. However, the influence of rotation on plasma stability and turbulence is more profound. At the macroscopic level it affects the behaviour of the gross MHD modes that influence plasma operational limits. This includes sawteeth, the seeding of neoclassical tearing modes, resistive wall modes and the onset of disruptions through error fields, mode locking and reconnection. At the microscopic level it has a major effect on the stability of ballooning modes, both ideal MHD and drift wave instabilities such as ion temperature gradient (ITG) modes. In the non-linear state, as unstable drift waves evolve into turbulent structures, sheared rotation also tears apart eddies, thereby reducing the resulting transport. There is considerable experimental evidence for these effects on both MHD stability and plasma confinement. In particular, the appearance of improved confinement modes with transport barriers, such as edge H-mode barriers and internal transport barriers (ITBs) appears to correlate well with the presence of sheared plasma rotation. This talk will describe the theory underlying some of these phenomena involving plasma rotation, on both macroscopic and microscopic

  8. On Job Rotation

    OpenAIRE

    Metin M. Cosgel; Thomas J. Miceli

    1998-01-01

    A fundamental principle of economics with which Adam Smith begins The Wealth of Nations is the division of labor. Some firms, however, have been pursuing a practice called job rotation, which assigns each worker not to a single and specific task but to a set of several tasks among which he or she rotates with some frequency. We examine the practice of job rotation as a serious alternative to specialization, with three objectives. The first is to consider current and historical examples of job...

  9. Solar radiophysics

    International Nuclear Information System (INIS)

    McLean, D.J.; Labrum, N.R.

    1985-01-01

    This book treats all aspects of solar radioastronomy at metre wavelengths, particularly work carried out on the Australian radioheliograph at Culgoora, with which most of the authors have been associated in one way or another. After an introductory section on historical aspects, the solar atmosphere, solar flares, and coronal radio emission, the book deals with instrumentation, theory, and details of observations and interpretations of the various aspects of metrewave solar radioastronomy, including burst types, solar storms, and the quiet sun. (U.K.)

  10. Rotator cuff - self-care

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000358.htm Rotator cuff - self-care To use the sharing features on ... and shoulder exercises may help ease your symptoms. Rotator Cuff Problems Common rotator cuff problems include: Tendinitis , which ...

  11. Solar Proton Events in Six Solar Cycles

    Science.gov (United States)

    Vitaly, Ishkov

    Based on materials the catalogs of solar proton events (SPE) in 1955 ‒ 2010 and list SPE for the current 24 solar cycle (SC) are examined confirmed SPE with E> 10 MeV proton flux in excess of 1 proton cm-2 s ster-1 (pfu) from Švestka and Simon’s (1955 - 1969) and 5 volumes Logachev’s (1970 - 2006) Catalogs of SPE. Historically thus it was formed, that the measurements of the proton fluxes began in the epoch “increased” solar activity (SC 18 ‒ 22), and includes transition period of the solar magnetic fields reconstruction from epoch “increased” to the epoch “lowered” solar activity (22 ‒ 23 SC). In current 24 SC ‒ first SC of the incipient epoch of “lowered” SA ‒ SPE realize under the new conditions, to that of previously not observed. As showed a study of five solar cycles with the reliable measurements of E> 10 MeV proton flux in excess of 1 pfu (1964 - 2013): ‒ a quantity of SPEs remained approximately identical in SC 20, 21, somewhat decreased in the initial solar cycle of the solar magnetic fields reconstruction period (22), but it returned to the same quantity in, the base for the period of reconstruction, SC 23. ‒ Into the first 5 years of the each solar cycle development the rate of the proton generation events noticeably increased in 22 cycles of solar activity and returned to the average in cycles 23 and 24. ‒ Extreme solar flare events are achieved, as a rule, in the solar magnetic fields reconstruction period (August - September 1859; June 1991; October ‒ November 2003.), it is confirmed also for SPE: the extreme fluxes of solar protons (S4) except one (August 1972) were occurred in period of perestroika (SC 22 and 23). This can speak, that inside the epochs SA, when the generation of magnetic field in the convective zone works in the steady-state regime, extreme SPE are improbable. ‒ The largest in the fluxes of protons (S3, S4) occur in the complexes of the active regions flare events, where magnetic field more

  12. Effects of Ultrafast Molecular Rotation on Collisional Decoherence

    Science.gov (United States)

    Milner, Alexander A.; Korobenko, Aleksey; Hepburn, John W.; Milner, Valery

    2014-07-01

    Using an optical centrifuge to control molecular rotation in an extremely broad range of angular momenta, we study coherent rotational dynamics of nitrogen molecules in the presence of collisions. We cover the range of rotational quantum numbers between J=8 and J =66 at room temperature and study a crossover between the adiabatic and nonadiabatic regimes of rotational relaxation, which cannot be easily accessed by thermal means. We demonstrate that the rate of rotational decoherence changes by more than an order of magnitude in this range of J values and show that its dependence on J can be described by a simplified scaling law.

  13. Equilibrium of rotating and nonrotating plasmas in tokamaks

    International Nuclear Information System (INIS)

    Pustovitov, V.D.

    2003-01-01

    One studied plasma equilibrium in tokamak in case of toroidal rotation. Rotation associated centrifugal force is shown to result in decrease of equilibrium limit as to β. One analyzes unlike opinion and considers its supports. It is shown that in possible case of local improvement of equilibrium conditions associated with special selection of profile of plasma rotation rate, the combined integral effect turns to be negative one. But in case of typical conditions, decrease of equilibrium β caused by plasma rotation is negligible one and one may ignore effect of plasma rotation on its equilibrium for hot plasma [ru

  14. The search for solar neutrinos

    International Nuclear Information System (INIS)

    Ryder, L.

    1976-01-01

    The pioneering work on the detection of solar neutrinos by R. Davis is discussed. The discrepancy between the theoretical neutrino flux rate, according to a recent standard solar model, of 5.6 solar neutrino units (SNU) and the observed rate of 1 SNU together with three suggested solutions of the discrepancy are examined. Very recently Davis has announced an increased count rate of about 4 SNU while groups in Birmingham and in the Crimea have reported solar oscillations. The impact of these latest developments is discussed. (U.K.)

  15. Quasi-biennial periodicity in the solar neutrino flux and its relation to the solar structure

    International Nuclear Information System (INIS)

    Sakurai, K.

    1981-01-01

    By analysing the observed results on the neutrino flux from the Sun for the years 1970-1978, it is shown that the production rate of the neutrinos at the central core of the Sun had been varying with a period almost equal to 26 months for these years. This so-called 'quasi-biennial' periodicity in this rate suggests that the physical state of the central core of the Sun must have been modulated with this period through the variation of physical parameters as temperature and the chemial composition at the central core of the Sun. An idea to interpret this observed periodicity is thus proposed by taking the variations of these parameters into consideration. Some supporting evidence on this periodicity can be found on the variations of the solar activity as the relative sunspot numbers and the equatorial rotation speed of the Sun. (orig.)

  16. Rotating universe models

    International Nuclear Information System (INIS)

    Tozini, A.V.

    1984-01-01

    A review is made of some properties of the rotating Universe models. Godel's model is identified as a generalized filted model. Some properties of new solutions of the Einstein's equations, which are rotating non-stationary Universe models, are presented and analyzed. These models have the Godel's model as a particular case. Non-stationary cosmological models are found which are a generalization of the Godel's metrics in an analogous way in which Friedmann is to the Einstein's model. (L.C.) [pt

  17. Rotation Invariance Neural Network

    OpenAIRE

    Li, Shiyuan

    2017-01-01

    Rotation invariance and translation invariance have great values in image recognition tasks. In this paper, we bring a new architecture in convolutional neural network (CNN) named cyclic convolutional layer to achieve rotation invariance in 2-D symbol recognition. We can also get the position and orientation of the 2-D symbol by the network to achieve detection purpose for multiple non-overlap target. Last but not least, this architecture can achieve one-shot learning in some cases using thos...

  18. Novel Method for Measuring the Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters Based on Artificial Neural Networks and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhijian Liu

    2015-08-01

    Full Text Available The determinations of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, which also wastes too much time and manpower. To address this problem, we propose machine learning models including artificial neural networks (ANNs and support vector machines (SVM to predict the heat collection rate and heat loss coefficient without a direct determination. Parameters that can be easily obtained by “portable test instruments” were set as independent variables, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, final temperature and angle between tubes and ground, while the heat collection rate and heat loss coefficient determined by the detection device were set as dependent variables respectively. Nine hundred fifteen samples from in-service water-in-glass evacuated tube solar water heaters were used for training and testing the models. Results show that the multilayer feed-forward neural network (MLFN with 3 nodes is the best model for the prediction of heat collection rate and the general regression neural network (GRNN is the best model for the prediction of heat loss coefficient due to their low root mean square (RMS errors, short training times, and high prediction accuracies (under the tolerances of 30%, 20%, and 10%, respectively.

  19. Deciphering Solar Magnetic Activity: Spotting Solar Cycle 25

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Scott W. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Leamon, Robert J., E-mail: mscott@ucar.edu [Department of Astronomy, University of Maryland, College Park, MD (United States)

    2017-06-26

    We present observational signatures of solar cycle 25 onset. Those signatures are visibly following a migratory path from high to low latitudes. They had starting points that are asymmetrically offset in each hemisphere at times that are 21–22 years after the corresponding, same polarity, activity bands of solar cycle 23 started their migration. Those bands define the so-called “extended solar cycle.” The four magnetic bands currently present in the system are approaching a mutually cancelling configuration, and solar minimum conditions are imminent. Further, using a tuned analysis of the daily band latitude-time diagnostics, we are able to utilize the longitudinal wave number (m = 1) variation in the data to more clearly reveal the presence of the solar cycle 25 bands. This clarification illustrates that prevalently active longitudes (different in each hemisphere) exist at mid-latitudes presently, lasting many solar rotations, that can be used for detailed study over the next several years with instruments like the Spectrograph on IRIS, the Spectropolarimeter on Hinode, and, when they come online, similar instruments on the Daniel K. Inouye Solar Telescope (DKIST) as we watch those bands evolve following the cancellation of the solar cycle 24 activity bands at the equator late in 2019.

  20. Rotating detectors and Mach's principle

    International Nuclear Information System (INIS)

    Paola, R.D.M. de; Svaiter, N.F.

    2000-08-01

    In this work we consider a quantum version of Newton s bucket experiment in a fl;at spacetime: we take an Unruh-DeWitt detector in interaction with a real massless scalar field. We calculate the detector's excitation rate when it is uniformly rotating around some fixed point and the field is prepared in the Minkowski vacuum and also when the detector is inertial and the field is in the Trocheries-Takeno vacuum state. These results are compared and the relations with Mach's principle are discussed. (author)

  1. M Dwarf Rotation from the K2 Young Clusters to the Field. I. A Mass-Rotation Correlation at 10 Myr

    Science.gov (United States)

    Somers, Garrett; Stauffer, John; Rebull, Luisa; Cody, Ann Marie; Pinsonneault, Marc

    2017-12-01

    Recent observations of the low-mass (0.1-0.6 {M}⊙ ) rotation distributions of the Pleiades and Praesepe clusters have revealed a ubiquitous correlation between mass and rotation, such that late M dwarfs rotate an order-of-magnitude faster than early M dwarfs. In this paper, we demonstrate that this mass-rotation correlation is present in the 10 Myr Upper Scorpius association, as revealed by new K2 rotation measurements. Using rotational evolution models, we show that the low-mass rotation distribution of the 125 Myr Pleiades cluster can only be produced if it hosted an equally strong mass-rotation correlation at 10 Myr. This suggests that physical processes important in the early pre-main sequence (PMS; star formation, accretion, disk-locking) are primarily responsible for the M dwarf rotation morphology, and not quirks of later angular momentum (AM) evolution. Such early mass trends must be taken into account when constructing initial conditions for future studies of stellar rotation. Finally, we show that the average M star loses ˜25%-40% of its AM between 10 and 125 Myr, a figure accurately and generically predicted by modern solar-calibrated wind models. Their success rules out a lossless PMS and validates the extrapolation of magnetic wind laws designed for solar-type stars to the low-mass regime at early times.

  2. KIC 9451096: Magnetic Activity, Flares and Differential Rotation

    Science.gov (United States)

    Özdarcan, O.; Yoldaş, E.; Dal, H. A.

    2018-04-01

    We present a spectroscopic and photometric analysis of KIC 9451096. The combined spectroscopic and photometric modelling shows that the system is a detached eclipsing binary in a circular orbit and composed of F5V + K2V components. Subtracting the best-fitting light curve model from the whole long cadence data reveals additional low (mmag) amplitude light variations in time and occasional flares, suggesting a low, but still remarkable level of magnetic spot activity on the K2V component. Analyzing the rotational modulation of the light curve residuals enables us to estimate the differential rotation coefficient of the K2V component as k = 0.069 ± 0.008, which is 3 times weaker compared with the solar value of k = 0.19, assuming a solar type differential rotation. We find the stellar flare activity frequency for the K2V component as 0.000368411 h-1 indicating a low magnetic activity level.

  3. The measurement of solar magnetic fields

    International Nuclear Information System (INIS)

    Stenflo, J.O.

    1978-01-01

    Solar activity is basically caused by the interaction between magnetic fields, solar rotation and convective motions. Detailed mapping of the Sun's rapidly varying magnetic field helps in the understanding of the mechanisms of solar activity. Observations in recent years have revealed unexpected and intriguing properties of solar magnetic fields, the explanation of which has become a challenge to plasma physicists. This review deals primarily with how the Sun's magnetic field is measured, but it also includes a brief review of the present observational picture of the magnetic field, which is needed to understand the problems of how to properly interpret the observations. 215 references. (author)

  4. Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems

    Science.gov (United States)

    Ramakumar, R.; Bahrami, K.

    1981-01-01

    This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

  5. Solar energy

    International Nuclear Information System (INIS)

    Kruisheer, N.

    1992-01-01

    In five brief articles product information is given on solar energy applications with special attention to the Netherlands. After an introduction on solar energy availability in the Netherlands the developments in solar boiler techniques are dealt with. Solar water heaters have advantages for the environment, and government subsidies stimulate different uses of such water heaters. Also the developments of solar cells show good prospects, not only for developing countries, but also for the industrialized countries. In brief the developments in solar energy storage and the connection of solar equipment to the grid are discussed. Finally attention is paid to the applications of passive solar energy in the housing construction, the use of transparent thermal insulation and the developments of translucent materials. 18 figs., 18 ills

  6. Solar Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar photographic and illustrated datasets contributed by a number of national and private solar observatories located worldwide....

  7. Solar Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar feature datasets contributed by a number of national and private solar observatories located worldwide.

  8. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  9. The rotation of Titan and Ganymede

    Science.gov (United States)

    Van Hoolst, Tim; Coyette, Alexis; Baland, Rose-Marie; Trinh, Antony

    2016-10-01

    The rotation rates of Titan and Ganymede, the largest satellites of Saturn and Jupiter, are on average equal to their orbital mean motion. Here we discuss small deviations from the average rotation for both satellites and evaluate the polar motion of Titan induced by its surface fluid layers. We examine different causes at various time scales and assess possible consequences and the potential of using librations and polar motion as probes of the interior structure of the satellites.The rotation rate of Titan and Ganymede cannot be constant on the orbital time scale as a result of the gravitational torque of the central planet acting on the satellites. Titan is moreover expected to show significant polar motion and additional variations in the rotation rate due to angular momentum exchange with the atmosphere, mainly at seasonal periods. Observational evidence for deviations from the synchronous state has been reported several times for Titan but is unfortunately inconclusive. The measurements of the rotation variations are based on determinations of the shift in position of Cassini radar images taken during different flybys. The ESA JUICE (JUpiter ICy moons Explorer) mission will measure the rotation variations of Ganymede during its orbital phase around the satellite starting in 2032.We report on different theoretical aspects of the librations and polar motion. We consider the influence of the rheology of the ice shell and take into account Cassini measurements of the external gravitational field and of the topography of Titan and similar Galileo data about Ganymede. We also evaluate the librations and polar motion induced by Titan's hydrocarbon seas and use the most recent results of Titan's atmosphere dynamics. We finally evaluate the potential of rotation variations to constrain the satellite's interior structure, in particular its ice shell and ocean.

  10. Evolution of rotating stars. III. Predicted surface rotation velocities for stars which conserve total angular momentum

    International Nuclear Information System (INIS)

    Endal, A.S.; Sofia, S.

    1979-01-01

    Predicted surface rotation velocities are presented for Population I stars at 10, 7, 5, 3, and 1.5M/sub sun/. The surface velocities have been computed for three different cases of angular momentum redistribution: no radial redistribution (rotation on decoupled shells), complete redistribution (rigid-body rotation), and partial redistribution as predicted by detailed consideration of circulation currents in rotation stars. The velocities for these cases are compared to each other and to observed stellar rotation rates (upsilon sin i).Near the main sequence, rotational effects can substantially reduce the moment of inertia of a star, so nonrotating models consistently underestimate the expected velocities for evolving stars. The magnitude of these effects is sufficient to explain the large numbers of Be stars and, perhaps, to explain the bimodal distribution of velocities observed for the O stars.On the red giant branch, angular momentum redistribution reduces the surface velocity by a factor of 2 or more, relative to the velocity expected for no radial redistribution. This removes the discrepancy between predicted and observed rotation rates for the K giants and makes it unlikely that these stars lose significant amounts of angular momentum by stellar winds. Our calculations indicate that improved observations (by the Fourier-transform technique) of the red giants in the Hyades cluster can be used to determine how angular momentum is redistributed by convection

  11. Decrease in Hysteresis of Planetary Climate for Planets with Long Solar Days

    Science.gov (United States)

    Abbot, Dorian S.; Bloch-Johnson, Jonah; Checlair, Jade; Farahat, Navah X.; Graham, R. J.; Plotkin, David; Popovic, Predrag; Spaulding-Astudillo, Francisco

    2018-02-01

    The ice-albedo feedback on rapidly rotating terrestrial planets in the habitable zone can lead to abrupt transitions (bifurcations) between a warm and a snowball (ice-covered) state, bistability between these states, and hysteresis in planetary climate. This is important for planetary habitability because snowball events may trigger rises in the complexity of life, but could also endanger complex life that already exists. Recent work has shown that planets tidally locked in synchronous rotation states will transition smoothly into the snowball state rather than experiencing bifurcations. Here we investigate the structure of snowball bifurcations on planets that are tidally influenced, but not synchronously rotating, so that they experience long solar days. We use PlaSIM, an intermediate-complexity global climate model, with a thermodynamic mixed layer ocean and the Sun’s spectrum. We find that the amount of hysteresis (the range in stellar flux for which there is bistability in climate) is significantly reduced for solar days with lengths of tens of Earth days, and disappears for solar days of hundreds of Earth days. These results suggest that tidally influenced planets orbiting M and K stars that are not synchronously rotating could have much less hysteresis associated with the snowball bifurcations than they would if they were rapidly rotating. This implies that the amount of time it takes them to escape a snowball state via CO2 outgassing would be greatly reduced, as would the period of cycling between the warm and snowball state if they have low CO2 outgassing rates.

  12. K2 & Solar System Science

    Science.gov (United States)

    Lissauer, Jack

    2015-01-01

    All of the fields that K2 observes are near the ecliptic plane in order to minimize the spin-up of the spacecraft in response to the effects of solar irradiation. The fields observed by K2 are thus rich in Solar System objects including planets, asteroids and trans-Neptunian objects (TNOs). K2 has already performed observations of Neptune and its large moon Triton, 68 Trojan and Hilda asteroids, 5 TNOs (including Pluto) and Comet C/2013 A1 (Siding Springs). About 10,000 main-belt asteroids that fell into the pixel masks of stars have been serendipitously observed. Observations of small bodies are especially useful for determining rotation periods. Uranus will be observed in a future campaign (C8), as will many more small Solar System bodies. The status of various K2 Solar System studies will be reviewed and placed within the context of our current knowledge of the objects being observed.

  13. Solar Special

    International Nuclear Information System (INIS)

    Van Roekel, A.; Osborne, J.; Schroeter, S.; De Jong, R.; De Saint Jacob, Y.

    2009-01-01

    Solar power is growing much faster than most policymakers and analysts realise. As costs come down and feed-in tariffs go up across Europe, a number of countries have started in pursuit of market leader Germany. But in Germany criticism is growing of the multi-billion-euro support schemes that keep the solar industry booming. In this section of the magazine several articles are dedicated to developments in solar energy in Europe. The first article is an overview story on the strong growing global market for solar cells, mainly thanks to subsidy schemes. The second article is on the position of foreign companies in the solar market in Italy. Article number three is dedicated to the conditions for solar technology companies to establish themselves in the German state of Saxony. Also the fifth article deals with the development of solar cells in Saxony: scientists, plant manufacturers and module producers in Saxony are working on new technologies that can be used to produce solar electricity cost-effectively. The goal is to bring the price down to match that of conventionally generated electricity within the next few years. The sixth article deals with the the solar power market in Belgium, which may be overheated or 'oversubsidized'. Article seven is on France, which used to be a pioneer in solar technology, but now produces only a fraction of the solar output of market leader Germany. However, new attractive feed-in-tariffs are changing the solar landscape drastically

  14. The optical rotator

    DEFF Research Database (Denmark)

    Tandrup, T; Gundersen, Hans Jørgen Gottlieb; Jensen, Eva B. Vedel

    1997-01-01

    further discuss the methods derived from this principle and present two new local volume estimators. The optical rotator benefits from information obtained in all three dimensions in thick sections but avoids over-/ underprojection problems at the extremes of the cell. Using computer-assisted microscopes......The optical rotator is an unbiased, local stereological principle for estimation of cell volume and cell surface area in thick, transparent slabs, The underlying principle was first described in 1993 by Kieu Jensen (T. Microsc. 170, 45-51) who also derived an estimator of length, In this study we...... the extra measurements demand minimal extra effort and make this estimator even more efficient when it comes to estimation of individual cell size than many of the previous local estimators, We demonstrate the principle of the optical rotator in an example (the cells in the dorsal root ganglion of the rat...

  15. Vibrations of rotating machinery

    CERN Document Server

    Matsushita, Osami; Kanki, Hiroshi; Kobayashi, Masao; Keogh, Patrick

    2017-01-01

    This book opens with an explanation of the vibrations of a single degree-of-freedom (dof) system for all beginners. Subsequently, vibration analysis of multi-dof systems is explained by modal analysis. Mode synthesis modeling is then introduced for system reduction, which aids understanding in a simplified manner of how complicated rotors behave. Rotor balancing techniques are offered for rigid and flexible rotors through several examples. Consideration of gyroscopic influences on the rotordynamics is then provided and vibration evaluation of a rotor-bearing system is emphasized in terms of forward and backward whirl rotor motions through eigenvalue (natural frequency and damping ratio) analysis. In addition to these rotordynamics concerning rotating shaft vibration measured in a stationary reference frame, blade vibrations are analyzed with Coriolis forces expressed in a rotating reference frame. Other phenomena that may be assessed in stationary and rotating reference frames include stability characteristic...

  16. Quadrupole collective excitations in rapidly rotating nuclej

    International Nuclear Information System (INIS)

    Mikhajlov, I.N.

    1983-01-01

    The spectrum of collective quadrupole excitations in nuclei is investigated. The average nucleus field has the axial symmetry and rotation occurs relatively to this axis. Dependences of the spectrum of quadrupole oscillations on rotation rate for classic liquid drop (CLD) and for a drop of fermi-liquid (DFL) with fissionability parameter X=0.62 ( 154 Er) are presented. The dependence of probabilities of E2-transitions between single-phonon and phonon-free states on rotation rate for CLD and DFL with fussionability parameter X=0.62 ( 154 Er) is also presented. It is shown that for CLD collective E2-transition of states of yrast-consequence is absolutely forbidden. For DFL transitions are possible that lead to decay of phonon-free state with the excitation of phonons of γ-modes and decrease of angular momentum

  17. Rotating quantum states

    International Nuclear Information System (INIS)

    Ambruş, Victor E.; Winstanley, Elizabeth

    2014-01-01

    We revisit the definition of rotating thermal states for scalar and fermion fields in unbounded Minkowski space–time. For scalar fields such states are ill-defined everywhere, but for fermion fields an appropriate definition of the vacuum gives thermal states regular inside the speed-of-light surface. For a massless fermion field, we derive analytic expressions for the thermal expectation values of the fermion current and stress–energy tensor. These expressions may provide qualitative insights into the behaviour of thermal rotating states on more complex space–time geometries

  18. Rotating bubble membrane radiator

    Science.gov (United States)

    Webb, Brent J.; Coomes, Edmund P.

    1988-12-06

    A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating bubble membrane radiator, where it is sprayed into the interior of the bubble. Liquid impacting upon the interior surface of the bubble is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.

  19. Solar Indices - Solar Radio Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  20. Lifetime and production rate of NOx in the upper stratosphere and lower mesosphere in the polar spring/summer after the solar proton event in October–November 2003

    Directory of Open Access Journals (Sweden)

    F. Friederich

    2013-03-01

    Full Text Available We present altitude-dependent lifetimes of NOx, determined with MIPAS/ENVISAT (the Michelson Interferometer for Passive Atmospheric Sounding/the European Environment Satellite, for the Southern polar region after the solar proton event in October–November 2003. Between 50° S and 90° S and decreasing in altitude they range from about two days at 64 km to about 20 days at 44 km. The lifetimes are controlled by transport, mixing and photochemistry. We infer estimates of dynamical lifetimes by comparison of the observed decay to photochemical lifetimes calculated with the SLIMCAT 3-D Model. Photochemical loss contributes to the observed NOx depletion by 0.1% at 44 km, increasing with altitude to 45% at 64 km. In addition, we show the correlation of modelled ionization rates and observed NOx densities under consideration of the determined lifetimes of NOx, and calculate altitude-dependent effective production rates of NOx due to ionization. For that we compare ionization rates of the AIMOS data base with the MIPAS measurements from 15 October–31 December 2003. We derive effective NOx-production rates to be applied to the AIMOS ionization rates which range from about 0.2 NOx-molecules per ion pair at 44 km to 0.7 NOx-molecules per ion pair at 62 km. These effective production rates are considerably lower than predicted by box model simulations which could hint at an overestimation of the modelled ionization rates.

  1. Free Biceps Tendon Autograft to Augment Arthroscopic Rotator Cuff Repair

    OpenAIRE

    Obma, Padraic R.

    2013-01-01

    Arthroscopic rotator cuff repairs have become the standard of treatment for all sizes of tears over the past several years. Current healing rates reported in the literature are quite good, but improving the healing potential of rotator cuff repairs remains a challenging problem. There has been an increase recently in the use of augmentation of rotator cuff repairs with xenografts or synthetics for large and massive tears. Biceps tenodesis is often indicated as part of the treatment plan while...

  2. Radio Remote Sensing of Coronal Mass Ejections: Implications for Parker Solar Probe and Solar Orbiter

    Science.gov (United States)

    Kooi, J. E.; Thomas, N. C.; Guy, M. B., III; Spangler, S. R.

    2017-12-01

    Coronal mass ejections (CMEs) are fast-moving magnetic field structures of enhanced plasma density that play an important role in space weather. The Solar Orbiter and Parker Solar Probe will usher in a new era of in situ measurements, probing CMEs within distances of 60 and 10 solar radii, respectively. At the present, only remote-sensing techniques such as Faraday rotation can probe the plasma structure of CMEs at these distances. Faraday rotation is the change in polarization position angle of linearly polarized radiation as it propagates through a magnetized plasma (e.g. a CME) and is proportional to the path integral of the electron density and line-of-sight magnetic field. In conjunction with white-light coronagraph measurements, Faraday rotation observations have been used in recent years to determine the magnetic field strength of CMEs. We report recent results from simultaneous white-light and radio observations made of a CME in July 2015. We made radio observations using the Karl G. Jansky Very Large Array (VLA) at 1 - 2 GHz frequencies of a set of radio sources through the solar corona at heliocentric distances that ranged between 8 - 23 solar radii. These Faraday rotation observations provide a priori estimates for comparison with future in situ measurements made by the Solar Orbiter and Parker Solar Probe. Similar Faraday rotation observations made simultaneously with observations by the Solar Orbiter and Parker Solar Probe in the future could provide information about the global structure of CMEs sampled by these probes and, therefore, aid in understanding the in situ measurements.

  3. A Survey of Rotation Lightcurves of Small Jovian Trojan Asteroids in the L4 Cloud

    Science.gov (United States)

    French, Linda M.; Stephens, Robert; Warner, Brian; James, David; Rohl, Derrick; Connour, Kyle

    2017-10-01

    Jovian Trojan asteroids are of interest both as objects in their own right and as possible relics of Solar System formation. Several lines of evidence support a common origin for, and possible hereditary link between, Jovian Trojan asteroids and cometary nuclei. Asteroid lightcurves give information about processes that have affected a group of asteroids including their density. Due to their distance and low albedos, few comet-sized Trojans have been studied. We have been carrying out a survey of Trojan lightcurve properties comparing small Trojan asteroids with comets (French et al 2015). We present new lightcurve information for 39 Trojans less than about 35 km in diameter. We report our latest results and compare them with results from the sparsely-sampled lightcurves from the Palomar Transient Factory (Waszazak et al., Chang et al. 2015). The minimum densities for objects with complete lightcurves are estimated and are found to becomparable to those measured for cometary nuclei. A significant fraction (~40%) of thisobserved small Trojan population rotates slowly (P > 24 hours), with measured periods as over 500 hours (Waszczak et al 2015). The excess of slow rotators may be due to the YORP effect. Results of the Kolmogorov-Smirnov test suggest that the distribution of Trojan rotation rates is dissimilar to those of Main Belt Asteroids of the same size.

  4. Meridional circulation in rotating stars. VII. The effects of chemical inhomogeneities

    International Nuclear Information System (INIS)

    Tassoul, M.; Tassoul, J.

    1984-01-01

    In this paper we discuss the effects of a gradient of mean molecular weight μ on the rotationally driven currents that pervade the radiative zone of a single, nonmagnetic, main-sequence star. Detailed numerical calculations are made for the hydrogen-burning core of a solar-type star, assuming that departures from spherical symmetry are not too large. It is found that meridional streaming virtually dies out from the center outward as the μ-gradient grows in a leisurely fashion. This prevents a substantial mixing of matter between the inner (inhomogeneous) and outer (homogeneous) regions in the radiative zone, although the inner region may be penetrated to some degree. To first order in the ratio of the centrifugal force to gravity at the equator, this pattern of circulation is independent of the mean angular velocity. To this order, then, there is no critical rotation rate above which unimpeded mixing may take place. These quantitative results are compared with diverse statements that can be found in the phenomenological literature on rotational mixing

  5. Recurrent star-spot activity and differential rotation in KIC 11560447

    Science.gov (United States)

    Özavcı, I.; Şenavcı, H. V.; Işık, E.; Hussain, G. A. J.; O'Neal, D.; Yılmaz, M.; Selam, S. O.

    2018-03-01

    We present a detailed analysis of surface inhomogeneities on the K1-type subgiant component of the rapidly rotating eclipsing binary KIC 11560447, using high-precision Kepler light curves spanning nearly 4 yr, which corresponds to about 2800 orbital revolutions. We determine the system parameters precisely, using high-resolution spectra from the 2.1-m Otto Struve Telescope at the McDonald Observatory. We apply the maximum entropy method to reconstruct the relative longitudinal spot occupancy. Our numerical tests show that the procedure can recover large-scale random distributions of individually unresolved spots, and it can track the phase migration of up to three major spot clusters. By determining the drift rates of various spotted regions in orbital longitude, we suggest a way to constrain surface differential rotation and we show that the results are consistent with periodograms. The K1IV star exhibits two mildly preferred longitudes of emergence, indications of solar-like differential rotation, and a 0.5-1.3-yr recurrence period in star-spot emergence, accompanied by a secular increase in the axisymmetric component of spot occupancy.

  6. Coupled solar still, solar heater

    Energy Technology Data Exchange (ETDEWEB)

    Davison, R R; Harris, W B; Moor, D H; Delyannis, A; Delyannis, E [eds.

    1976-01-01

    Computer simulation of combinations of solar stills and solar heaters indicates the probable economic advantage of such an arrangement in many locations if the size of the heater is optimized relative to that of the still. Experience with various low cost solar heaters is discussed.

  7. Solar Sailing

    Science.gov (United States)

    Johnson, Les

    2009-01-01

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

  8. Solar Plus: A Holistic Approach to Distributed Solar PV

    Energy Technology Data Exchange (ETDEWEB)

    O' Shaughnessy, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ardani, Kristen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-05-25

    Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domestic water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.

  9. Solar Plus: A Holistic Approach to Distributed Solar PV

    Energy Technology Data Exchange (ETDEWEB)

    OShaughnessy, Eric J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ardani, Kristen B. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cutler, Dylan S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Margolis, Robert M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-06-08

    Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domestic water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.

  10. Rotations and angular momentum

    International Nuclear Information System (INIS)

    Nyborg, P.; Froyland, J.

    1979-01-01

    This paper is devoted to the analysis of rotational invariance and the properties of angular momentum in quantum mechanics. In particular, the problem of addition of angular momenta is treated in detail, and tables of Clebsch-Gordan coefficients are included

  11. Negative Rotation Cinch Strap.

    Science.gov (United States)

    This project discloses an improved unitary parachute torso harness, having a single fastening means, wherein an auxillary tightening strap is...attached to the groin straps of said harness. Said auxillary straps are used to prevent torso rotation or harness slippage and to prevent harness elongation

  12. A rotating string

    International Nuclear Information System (INIS)

    Jensen, B.

    1993-06-01

    The author presents a global solution of Einstein's equations which represents a rotating cosmic string with a finite coreradius. The importance of pressure for the generation of closed timelike curves outside the coreregion of such strings is clearly displayed in this model due to the simplicity of the source. 10 refs

  13. Rotator Cuff Injuries.

    Science.gov (United States)

    Connors, G. Patrick

    Many baseball players suffer from shoulder injuries related to the rotator cuff muscles. These injuries may be classified as muscular strain, tendonitis or tenosynovitis, and impingement syndrome. Treatment varies from simple rest to surgery, so it is important to be seen by a physician as soon as possible. In order to prevent these injuries, the…

  14. Rotational dynamics with Tracker

    International Nuclear Information System (INIS)

    Eadkhong, T; Danworaphong, S; Rajsadorn, R; Jannual, P

    2012-01-01

    We propose the use of Tracker, freeware for video analysis, to analyse the moment of inertia (I) of a cylindrical plate. Three experiments are performed to validate the proposed method. The first experiment is dedicated to find the linear coefficient of rotational friction (b) for our system. By omitting the effect of such friction, we derive I for a cylindrical plate rotated around its central axis from the other two experiments based on the relation between torque and angular acceleration of rotational motion and conservation of energy. Movies of the rotating plate and hung masses are recorded. As a result, we have the deviation of I from its theoretical value of 0.4% and 3.3%, respectively. Our setup is completely constructed from locally available inexpensive materials and the experimental results indicate that the system is highly reliable. This work should pave the way for those who prefer to build a similar setup from scratch at relatively low cost compared to commercial units. (paper)

  15. The Axial Curve Rotator.

    Science.gov (United States)

    Hunter, Walter M.

    This document contains detailed directions for constructing a device that mechanically produces the three-dimensional shape resulting from the rotation of any algebraic line or curve around either axis on the coordinate plant. The device was developed in response to student difficulty in visualizing, and thus grasping the mathematical principles…

  16. 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

  17. Streaming potential near a rotating porous disk.

    Science.gov (United States)

    Prieve, Dennis C; Sides, Paul J

    2014-09-23

    Theory and experimental results for the streaming potential measured in the vicinity of a rotating porous disk-shaped sample are described. Rotation of the sample on its axis draws liquid into its face and casts it from the periphery. Advection within the sample engenders streaming current and streaming potential that are proportional to the zeta potential and the disk's major dimensions. When Darcy's law applies, the streaming potential is proportional to the square of the rotation at low rate but becomes invariant with rotation at high rate. The streaming potential is invariant with the sample's permeability at low rate and is proportional to the inverse square of the permeability at high rate. These predictions were tested by determining the zeta potential and permeability of the loop side of Velcro, a sample otherwise difficult to characterize; reasonable values of -56 mV for zeta and 8.7 × 10(-9) m(2) for the permeability were obtained. This approach offers the ability to determine both the zeta potential and the permeability of materials having open structures. Compressing them into a porous plug is unnecessary. As part of the development of the theory, a convenient formula for a flow-weighted volume-averaged space-charge density of the porous medium, -εζ/k, was obtained, where ε is the permittivity, ζ is the zeta potential, and k is the Darcy permeability. The formula is correct when Smoluchowski's equation and Darcy's law are both valid.

  18. Energy Transfer in Scattering by Rotating Potentials

    Indian Academy of Sciences (India)

    Quantum mechanical scattering theory is studied for time-dependent Schrödinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave ...

  19. Solar energy: Technology and applications

    Science.gov (United States)

    Williams, J. R.

    1974-01-01

    It is pointed out that in 1970 the total energy consumed in the U.S. was equal to the energy of sunlight received by only 0.15% of the land area of the continental U.S. The utilization of solar energy might, therefore, provide an approach for solving the energy crisis produced by the consumption of irreplaceable fossil fuels at a steadily increasing rate. Questions regarding the availability of solar energy are discussed along with the design of solar energy collectors and various approaches for heating houses and buildings by utilizing solar radiation. Other subjects considered are related to the heating of water partly or entirely with solar energy, the design of air conditioning systems based on the use of solar energy, electric power generation by a solar thermal and a photovoltaic approach, solar total energy systems, industrial and agricultural applications of solar energy, solar stills, the utilization of ocean thermal power, power systems based on the use of wind, and solar-energy power systems making use of geosynchronous power plants.

  20. Observations spotted solar type stars in Pleiades

    International Nuclear Information System (INIS)

    Magnitskij, A.K.

    1987-01-01

    The september - october 1986 observations discovered periodic light variations in three solar type stars in the Pleiades cluster: Hz 296 (0.8 M Sun ), Hz152(0.91 M Sun ) and Hz739(1.15 M Sun ). Periods and amplitudes are accordingly 2 d and 0 m .11, 4 d .12 and 0 m .07, 2 d .70 and 0 m .05. Considerable light variations of these stars in Pleiades are due to the rotation of spotted stars. Contrast spots of solar type stars likely exist when stars are young and rapidly rotate