WorldWideScience

Sample records for solar minima narrower

  1. Solar Twins and Stellar Maunder Minima

    Science.gov (United States)

    Hall, Jeffrey C.

    2012-05-01

    In 1966, Olin C. Wilson undertook an answer to the question “Does the chromospheric activity of main-sequence stars vary with time, and if so, how?”, initiating the so-called HK Project at Mount Wilson Observatory, which resulted in a magnificent 43-year data set and which has spawned a number of complementary synoptic programs in both hemispheres. Subsequent developments, in particular the realization that activity controls angular momentum evolution in the stars and Sun, that solar activity modulates irradiance, and that there was a pronounced response of terrestrial climate to the Maunder Minimum, spurred efforts to identify solar twins, stars that Giusa Cayrel de Strobel required to possess “fundamental physical parameters very similar, if not identical to those of the Sun.” Non-cycling states appear to occur in the Mount Wilson stars and in other synoptic data with about the same frequency that the Sun’s grand minima occur in the long-term proxy record, suggesting that stellar analogs of the Maunder Minimum may be used to guide understanding of the Sun’s state in the late seventeenth century and, as appears possible given the extended Cycle 23/24 minimum, in the near future. However, the magnitude limits of the existing surveys have kept the sample of solar twins small and long-term monitoring programs have only recently begun to accumulate good time-domain data beyond the canonical HK-index. Addressing these and other issues toward understanding prolonged stellar minima is therefore a key area of inquiry in solar-stellar connection work for the next decade. I will summarize the state of the field and the most promising lines of work for the immediate future. I and my colleagues Wes Lockwood and Brian Skiff sincerely appreciate the National Science Foundation’s long-time support of stellar cycles work at Lowell Observatory.

  2. Dynamical characterization of the last prolonged solar minima

    Science.gov (United States)

    Cionco, Rodolfo Gustavo; Compagnucci, Rosa Hilda

    2012-11-01

    The planetary hypothesis of the solar cycle is an old idea in which the gravitational influence of the planets has a non-negligible effect on the causes of the solar magnetic cycle. The advance of this hypothesis is based on phenomenological correlations between dynamical parameters of the Sun's movement around the barycentre of the Solar System and sunspots time series; and more especially, identifying relationships linking solar barycentric dynamics with prolonged minima (especially Grand Minima events). However, at present there is no clear physical mechanism relating these phenomena. The possible celestial influence on solar cycle modulation is of great importance not only in solar physics but also in Earth sciences, because prolonged solar minima have associated important climatic and telluric variations, in particular, during the Maunder and Dalton Minimum. In this work we looked for a possible causal link in relation with solar barycentric dynamics and prolonged minima events. We searched for particular changes in the Sun's acceleration and concentrated on long-term variations of the solar cycle. We show how the orbital angular momentum of the Sun evolves and how the inclination of the solar barycentric orbit varies during the epochs of orbital retrogressions. In particular, at these moments, the radial component of the Sun's acceleration (i.e., in the barycentre-Sun direction) had an exceptional magnitude. These radial impulses occurred at the very beginning of the Maunder Minimum, during the Dalton Minimum and also at the maximum of cycle 22 before the present extended minimum. We also found a strong correlation between the planetary torque and the observed sunspots international number around that maximum. We apply our results in a novel theory of Sun-planets interaction that it is sensitive to Sun barycentric dynamics and found a very important effect on the Sun's capability of storing hypothetical reservoirs of potential energy that could be released by

  3. Historical records of solar grand minima: a review

    Science.gov (United States)

    Vaquero, José M.

    2012-07-01

    Knowing solar activity during the past centuries is of great interest for many purposes. Historical documents can help us to know about the behaviour of the Sun during the last centuries. The observation of aurorae and naked-eye sunspots provides us with continuous information through the last few centuries that can be used to improve our knowledge of the long-term solar activity including solar Grand Minima. We have more or less detailed information on only one Grand minimum (the Maunder minimum in the second half of 17th century), which serves as an archetype for Grand minima in general. Telescopic sunspot records and measurements of solar diameter during Maunder minimum are available. In this contribution, I review some recent progress on these issues.

  4. Solar Cycle Variability and Grand Minima Induced by Joy's Law Scatter

    Science.gov (United States)

    Karak, Bidya Binay; Miesch, Mark S.

    2017-08-01

    The strength of the solar cycle varies from one cycle to another in an irregular manner and the extreme example of this irregularity is the Maunder minimum when Sun produced only a few spots for several years. We explore the cause of these variabilities using a 3D Babcock--Leighton dynamo. In this model, based on the toroidal flux at the base of the convection zone, bipolar magnetic regions (BMRs) are produced with flux, tilt angle, and time of emergence all obtain from their observed distributions. The dynamo growth is limited by a tilt quenching.The randomnesses in the BMR emergences make the poloidal field unequal and eventually cause an unequal solar cycle. When observed fluctuations of BMR tilts around Joy's law, i.e., a standard deviation of 15 degrees, are considered, our model produces a variation in the solar cycle comparable to the observed solar cycle variability. Tilt scatter also causes occasional Maunder-like grand minima, although the observed scatter does not reproduce correct statistics of grand minima. However, when we double the tilt scatter, we find grand minima consistent with observations. Importantly, our dynamo model can operate even during grand minima with only a few BMRs, without requiring any additional alpha effect.

  5. Polar and equatorial coronal hole winds at solar minima: From the heliosphere to the inner corona

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.; Landi, E., E-mail: lzh@umich.edu [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48105 (United States)

    2014-02-01

    Fast solar wind can be accelerated from at least two different sources: polar coronal holes and equatorial coronal holes. Little is known about the relationship between the wind coming from these two different latitudes and whether these two subcategories of fast wind evolve in the same way during the solar cycle. Nineteen years of Ulysses observations, from 1990 to 2009, combined with ACE observations from 1998 to the present provide us with in situ measurements of solar wind properties that span two entire solar cycles. These missions provide an ideal data set to study the properties and evolution of the fast solar wind originating from equatorial and polar holes. In this work, we focus on these two types of fast solar wind during the minima between solar cycles 22 and 23 and 23 and 24. We use data from SWICS, SWOOPS, and VHM/FGM on board Ulysses and SWICS, SWEPAM, and MAG on board ACE to analyze the proton kinetic, thermal, and dynamic characteristics, heavy ion composition, and magnetic field properties of these two fast winds. The comparison shows that: (1) their kinetic, thermal, compositional, and magnetic properties are significantly different at any time during the two minima and (2) they respond differently to the changes in solar activity from cycle 23 to 24. These results indicate that equatorial and polar fast solar wind are two separate subcategories of fast wind. We discuss the implications of these results and relate them to remote-sensing measurements of the properties of polar and equatorial coronal holes carried out in the inner corona during these two solar minima.

  6. Polar and equatorial coronal hole winds at solar minima: From the heliosphere to the inner corona

    International Nuclear Information System (INIS)

    Zhao, L.; Landi, E.

    2014-01-01

    Fast solar wind can be accelerated from at least two different sources: polar coronal holes and equatorial coronal holes. Little is known about the relationship between the wind coming from these two different latitudes and whether these two subcategories of fast wind evolve in the same way during the solar cycle. Nineteen years of Ulysses observations, from 1990 to 2009, combined with ACE observations from 1998 to the present provide us with in situ measurements of solar wind properties that span two entire solar cycles. These missions provide an ideal data set to study the properties and evolution of the fast solar wind originating from equatorial and polar holes. In this work, we focus on these two types of fast solar wind during the minima between solar cycles 22 and 23 and 23 and 24. We use data from SWICS, SWOOPS, and VHM/FGM on board Ulysses and SWICS, SWEPAM, and MAG on board ACE to analyze the proton kinetic, thermal, and dynamic characteristics, heavy ion composition, and magnetic field properties of these two fast winds. The comparison shows that: (1) their kinetic, thermal, compositional, and magnetic properties are significantly different at any time during the two minima and (2) they respond differently to the changes in solar activity from cycle 23 to 24. These results indicate that equatorial and polar fast solar wind are two separate subcategories of fast wind. We discuss the implications of these results and relate them to remote-sensing measurements of the properties of polar and equatorial coronal holes carried out in the inner corona during these two solar minima.

  7. Study of the equatorial ionosphere behavior over Brazilian region during the last two solar minima

    Science.gov (United States)

    Nicoli Candido, C. M.; Batista, I. S.

    2013-12-01

    The recent solar cycle 23-24 presented an unusually deep and long lasting minimum activity period. The impact of this solar minimum on the system magnetosphere-thermosphere-ionosphere has been the subject of several studies. In this study we use the measurements by digisondes installed in the Brazilian sector to investigate the climatology of the ionospheric parameters over Sao Luis (2.33 S degrees, 44.2 W degrees, dip angle: -6.7), an equatorial site, and over Cachoeira Paulista (23S degrees, 45 W degrees, dip angle: -37), a location over the southern crest of the equatorial ionospheric anomaly (EIA). The ionograms were manually scaled in order to extract the ionospheric parameters: hmF2 (the F2 layer peak height, in km) and foF2 (the F2 layer critical frequency, in MHz). The critical frequency is related to the peak electron density of the F2-layer, NmF2, where: NmF2= 1.24 x 1010 (foF2)2 el.m-3. We determine the monthly average values of these parameters to investigate the local time and the seasonal dependence on the solar activity. We also compare the ionospheric behavior during the last two solar minima period: the solar cycle 22-23 (1996) and the solar cycle 23-24 (2008-2009). It is observed that in general the plasma densities and F-region heights are lower in the recent solar minimum, compared to the last one, especially for lower latitude region. In addition, we observe the occurrence of F-region plasma irregularities around local midnight and during post-midnight hours, which present morphological features that are distinct from typical irregularities associated with post sunset equatorial spread-F. We discuss the dependence of the ionospheric behavior on the solar flux.

  8. The energy spectra of anomalous oxygen at the time of two successive solar minima

    CERN Document Server

    Kondratyeva, M A; Tretyakova, S P; Zhuravlev, D A

    1999-01-01

    The energy spectra of anomalous oxygen have been determined from nuclear track detectors exposed aboard the Earth-orbiting satellites at altitudes ranging from approx 250-400 km in two consecutive solar minimum periods of 1986-1987 and 1994-1995 with opposite polarity of the solar magnetic field. A comparison of the spectra shows no contradiction to current drift models.

  9. HEMISPHERIC ASYMMETRIES IN THE POLAR SOLAR WIND OBSERVED BY ULYSSES NEAR THE MINIMA OF SOLAR CYCLES 22 AND 23

    International Nuclear Information System (INIS)

    Ebert, R. W.; Dayeh, M. A.; Desai, M. I.; McComas, D. J.; Pogorelov, N. V.

    2013-01-01

    We examined solar wind plasma and interplanetary magnetic field (IMF) observations from Ulysses' first and third orbits to study hemispheric differences in the properties of the solar wind and IMF originating from the Sun's large polar coronal holes (PCHs) during the declining and minimum phase of solar cycles 22 and 23. We identified hemispheric asymmetries in several parameters, most notably ∼15%-30% south-to-north differences in averages for the solar wind density, mass flux, dynamic pressure, and energy flux and the radial and total IMF magnitudes. These differences were driven by relatively larger, more variable solar wind density and radial IMF between ∼36°S-60°S during the declining phase of solar cycles 22 and 23. These observations indicate either a hemispheric asymmetry in the PCH output during the declining and minimum phase of solar cycles 22 and 23 with the southern hemisphere being more active than its northern counterpart, or a solar cycle effect where the PCH output in both hemispheres is enhanced during periods of higher solar activity. We also report a strong linear correlation between these solar wind and IMF parameters, including the periods of enhanced PCH output, that highlight the connection between the solar wind mass and energy output and the Sun's magnetic field. That these enhancements were not matched by similar sized variations in solar wind speed points to the mass and energy responsible for these increases being added to the solar wind while its flow was subsonic.

  10. HEMISPHERIC ASYMMETRIES IN THE POLAR SOLAR WIND OBSERVED BY ULYSSES NEAR THE MINIMA OF SOLAR CYCLES 22 AND 23

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, R. W.; Dayeh, M. A.; Desai, M. I.; McComas, D. J. [Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 (United States); Pogorelov, N. V. [Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2013-05-10

    We examined solar wind plasma and interplanetary magnetic field (IMF) observations from Ulysses' first and third orbits to study hemispheric differences in the properties of the solar wind and IMF originating from the Sun's large polar coronal holes (PCHs) during the declining and minimum phase of solar cycles 22 and 23. We identified hemispheric asymmetries in several parameters, most notably {approx}15%-30% south-to-north differences in averages for the solar wind density, mass flux, dynamic pressure, and energy flux and the radial and total IMF magnitudes. These differences were driven by relatively larger, more variable solar wind density and radial IMF between {approx}36 Degree-Sign S-60 Degree-Sign S during the declining phase of solar cycles 22 and 23. These observations indicate either a hemispheric asymmetry in the PCH output during the declining and minimum phase of solar cycles 22 and 23 with the southern hemisphere being more active than its northern counterpart, or a solar cycle effect where the PCH output in both hemispheres is enhanced during periods of higher solar activity. We also report a strong linear correlation between these solar wind and IMF parameters, including the periods of enhanced PCH output, that highlight the connection between the solar wind mass and energy output and the Sun's magnetic field. That these enhancements were not matched by similar sized variations in solar wind speed points to the mass and energy responsible for these increases being added to the solar wind while its flow was subsonic.

  11. Comment on: “Solar Minima, Earth's rotation and Little Ice Ages in the past and in the future. The North Atlantic-European case” (Mörner, 2010)

    Science.gov (United States)

    Cheddadi, R.; Guiot, J.

    2011-04-01

    This is a comment on the following publication: Mörner, N-A. 2010. Solar Minima, Earth's rotation and Little Ice Ages in the past and in the future. The North Atlantic-European case. Global and Planetary Change, 72: 282-293.

  12. Efficient steam generation by inexpensive narrow gap evaporation device for solar applications.

    Science.gov (United States)

    Morciano, Matteo; Fasano, Matteo; Salomov, Uktam; Ventola, Luigi; Chiavazzo, Eliodoro; Asinari, Pietro

    2017-09-20

    Technologies for solar steam generation with high performance can help solving critical societal issues such as water desalination or sterilization, especially in developing countries. Very recently, we have witnessed a rapidly growing interest in the scientific community proposing sunlight absorbers for direct conversion of liquid water into steam. While those solutions can possibly be of interest from the perspective of the involved novel materials, in this study we intend to demonstrate that efficient steam generation by solar source is mainly due to a combination of efficient solar absorption, capillary water feeding and narrow gap evaporation process, which can also be achieved through common materials. To this end, we report both numerical and experimental evidence that advanced nano-structured materials are not strictly necessary for performing sunlight driven water-to-vapor conversion at high efficiency (i.e. ≥85%) and relatively low optical concentration (≈10 suns). Coherently with the principles of frugal innovation, those results unveil that solar steam generation for desalination or sterilization purposes may be efficiently obtained by a clever selection and assembly of widespread and inexpensive materials.

  13. Energy landscapes and persistent minima

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Joanne M.; Wales, David J., E-mail: dw34@cam.ac.uk [University Chemical Laboratories, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Mazauric, Dorian; Cazals, Frédéric, E-mail: frederic.cazals@inria.fr [Inria Sophia Antipolis Méditerranée, 2004 route des Lucioles, F-06902 Sophia Antipolis (France)

    2016-02-07

    We consider a coarse-graining of high-dimensional potential energy landscapes based upon persistences, which correspond to lowest barrier heights to lower-energy minima. Persistences can be calculated efficiently for local minima in kinetic transition networks that are based on stationary points of the prevailing energy landscape. The networks studied here represent peptides, proteins, nucleic acids, an atomic cluster, and a glassy system. Minima with high persistence values are likely to represent some form of alternative structural morphology, which, if appreciably populated at the prevailing temperature, could compete with the global minimum (defined as infinitely persistent). Threshold values on persistences (and in some cases equilibrium occupation probabilities) have therefore been used in this work to select subsets of minima, which were then analysed to see how well they can represent features of the full network. Simplified disconnectivity graphs showing only the selected minima can convey the funnelling (including any multiple-funnel) characteristics of the corresponding full graphs. The effect of the choice of persistence threshold on the reduced disconnectivity graphs was considered for a system with a hierarchical, glassy landscape. Sets of persistent minima were also found to be useful in comparing networks for the same system sampled under different conditions, using minimum oriented spanning forests.

  14. Bromine enrichment in marsh sediments as a marker of environmental changes driven by Grand Solar Minima and anthropogenic activity (Caminha, NW of Portugal).

    Science.gov (United States)

    Moreno, J; Fatela, F; Leorri, E; Araújo, M F; Moreno, F; De la Rosa, J; Freitas, M C; Valente, T; Corbett, D R

    2015-02-15

    A sediment core collected in Caminha tidal marsh, NW Portugal, was used to assess bromine (Br) signal over the last ca. 1,700 years. The Br temporal variability reflects its close relationship with soil/sediment organic matter (OM) and also alterations in Br biogeochemical recycling in marsh environment. The highest Br enrichment in sediments was found during the Maunder Solar Minimum, a major solar event characterized by lower irradiance (TSI) and temperature, increased cloudiness and albedo. The obtained results suggest that those climate-induced changes weakened the natural mechanisms that promote Br biochemical transformations, driven by both living plants metabolism and plant litter degradation, with the ensuing generation of volatile methyl bromide (CH3Br). It seems that the prevailing climate conditions during the Maunder favoured the retention of more Br in marsh ecosystem, ultimately decreasing the biogenic Br emissions to the atmosphere. During the 20th century, the Br pattern in sediments appears to mirror likewise anthropogenic sources. The significant correlation (pmarsh. Although man-made brominated compounds are being phased-out since the inception of the 1992 Montreal Protocol, the Caminha tidal marsh sedimentary record showed that Br levels only started to decline after 2002. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. ULTRA-NARROW NEGATIVE FLARE FRONT OBSERVED IN HELIUM-10830 Å USING THE 1.6 m NEW SOLAR TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yan; Liu, Chang; Jing, Ju; Wang, Haimin [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Blvd, Newark, NJ 07102-1982 (United States); Cao, Wenda; Gary, Dale [Big Bear Solar Observatory, New Jersey Institute of Technology 323 Martin Luther King Blvd, Newark, NJ 07102-1982 (United States); Ding, Mingde [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Kleint, Lucia [Fachhochschule Nordwestschweiz (FHNW), Institute of 4D technologies Bahnhofstr. 6, CH-5210 Windisch (Switzerland); Su, Jiangtao [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Ji, Haisheng [Purple Mountain Observatory, 2 Beijing Xi Lu, Nanjing, 210008 (China); Chae, Jongchul; Cho, Kyuhyoun [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Cho, Kyungsuk [Korea Astronomy and Space Science Institute, Daedeokdae-ro 776, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

    2016-03-10

    Solar flares are sudden flashes of brightness on the Sun and are often associated with coronal mass ejections and solar energetic particles that have adverse effects on the near-Earth environment. By definition, flares are usually referred to as bright features resulting from excess emission. Using the newly commissioned 1.6 m New Solar Telescope at Big Bear Solar Observatory, we show a striking “negative” flare with a narrow but unambiguous “dark” moving front observed in He i 10830 Å, which is as narrow as 340 km and is associated with distinct spectral characteristics in Hα and Mg ii lines. Theoretically, such negative contrast in He i 10830 Å can be produced under special circumstances by nonthermal electron collisions or photoionization followed by recombination. Our discovery, made possible due to unprecedented spatial resolution, confirms the presence of the required plasma conditions and provides unique information in understanding the energy release and radiative transfer in astronomical objects.

  16. Interface band gap narrowing behind open circuit voltage losses in Cu2ZnSnS4 solar cells

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Palsgaard, Mattias Lau Nøhr; Gunst, Tue

    2017-01-01

    We present evidence that bandgap narrowing at the heterointerface may be a major cause of the large open circuit voltage deficit of Cu2ZnSnS4/CdS solar cells. Bandgap narrowing is caused by surface states that extend the Cu2ZnSnS4valence band into the forbidden gap. Those surface states...... voltage measurements on Cu2ZnSnS4 solar cells can be reproduced quantitatively without necessarily assuming a cliff-like conduction band offset with the CdS buffer layer. Our first-principles calculations indicate that Zn-based alternative buffer layers are advantageous due to the ability of...... Zn to passivate those surface states. Focusing future research on Zn-based buffers is expected to significantly improve the open circuit voltage and efficiency of pure-sulfide Cu2ZnSnS4 solar cells....

  17. Interface band gap narrowing behind open circuit voltage losses in Cu2ZnSnS4 solar cells

    Science.gov (United States)

    Crovetto, Andrea; Palsgaard, Mattias L. N.; Gunst, Tue; Markussen, Troels; Stokbro, Kurt; Brandbyge, Mads; Hansen, Ole

    2017-02-01

    We present evidence that bandgap narrowing at the heterointerface may be a major cause of the large open circuit voltage deficit of Cu2ZnSnS4/CdS solar cells. Bandgap narrowing is caused by surface states that extend the Cu2ZnSnS4 valence band into the forbidden gap. Those surface states are consistently found in Cu2ZnSnS4, but not in Cu2ZnSnSe4, by first-principles calculations. They do not simply arise from defects at surfaces but are an intrinsic feature of Cu2ZnSnS4 surfaces. By including those states in a device model, the outcome of previously published temperature-dependent open circuit voltage measurements on Cu2ZnSnS4 solar cells can be reproduced quantitatively without necessarily assuming a cliff-like conduction band offset with the CdS buffer layer. Our first-principles calculations indicate that Zn-based alternative buffer layers are advantageous due to the ability of Zn to passivate those surface states. Focusing future research on Zn-based buffers is expected to significantly improve the open circuit voltage and efficiency of pure-sulfide Cu2ZnSnS4 solar cells.

  18. Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Bedair, Salah M. [North Carolina State Univ., Raleigh, NC (United States); Hauser, John R. [North Carolina State Univ., Raleigh, NC (United States); Elmasry, Nadia [North Carolina State Univ., Raleigh, NC (United States); Colter, Peter C. [North Carolina State Univ., Raleigh, NC (United States); Bradshaw, G. [North Carolina State Univ., Raleigh, NC (United States); Carlin, C. Z. [North Carolina State Univ., Raleigh, NC (United States); Samberg, J. [North Carolina State Univ., Raleigh, NC (United States); Edmonson, Kenneth [Spectrolab, Inc., Sylmar, CA (United States)

    2012-07-31

    We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the InxGa1-xAs/GaAs1-yPy SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

  19. SUPRATHERMAL ELECTRON STRAHL WIDTHS IN THE PRESENCE OF NARROW-BAND WHISTLER WAVES IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Kajdič, P. [Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City (Mexico); Alexandrova, O.; Maksimovic, M.; Lacombe, C. [LESIA, Observatoire de Paris, PSL Research University, CNRS, UPMC UniversitéParis 06, Université Paris-Diderot, 5 Place Jules Janssen, F-92190 Meudon (France); Fazakerley, A. N., E-mail: primoz@geofisica.unam.mx [Mullard Space Science Laboratory, University College London (United Kingdom)

    2016-12-20

    We perform the first statistical study of the effects of the interaction of suprathermal electrons with narrow-band whistler mode waves in the solar wind (SW). We show that this interaction does occur and that it is associated with enhanced widths of the so-called strahl component. The latter is directed along the interplanetary magnetic field away from the Sun. We do the study by comparing the strahl pitch angle widths in the SW at 1 AU in the absence of large scale discontinuities and transient structures, such as interplanetary shocks, interplanetary coronal mass ejections, stream interaction regions, etc. during times when the whistler mode waves were present and when they were absent. This is done by using the data from two Cluster instruments: Spatio Temporal Analysis of Field Fluctuations experiment (STAFF) data in the frequency range between ∼0.1 and ∼200 Hz were used for determining the wave properties and Plasma Electron And Current Experiment (PEACE) data sets at 12 central energies between ∼57 eV (equivalent to ∼10 typical electron thermal energies in the SW, E{sub T}) and ∼676 eV (∼113 E{sub T}) for pitch angle measurements. Statistical analysis shows that, during the intervals with the whistler waves, the strahl component on average exhibits pitch angle widths between 2° and 12° larger than during the intervals when these waves are not present. The largest difference is obtained for the electron central energy of ∼344 eV (∼57 ET).

  20. The Nature of Grand Minima and Maxima from Fully Nonlinear Flux Transport Dynamos

    Energy Technology Data Exchange (ETDEWEB)

    Inceoglu, Fadil; Arlt, Rainer [Leibniz-Institute for Astrophysics Potsdam, An der Sternwarte 16, D-14482, Potsdam (Germany); Rempel, Matthias, E-mail: finceoglu@aip.de [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2017-10-20

    We aim to investigate the nature and occurrence characteristics of grand solar minimum and maximum periods, which are observed in the solar proxy records such as {sup 10}Be and {sup 14}C, using a fully nonlinear Babcock–Leighton type flux transport dynamo including momentum and entropy equations. The differential rotation and meridional circulation are generated from the effect of turbulent Reynolds stress and are subjected to back-reaction from the magnetic field. To generate grand minimum- and maximum-like periods in our simulations, we used random fluctuations in the angular momentum transport process, namely the Λ-mechanism, and in the Babcock–Leighton mechanism. To characterize the nature and occurrences of the identified grand minima and maxima in our simulations, we used the waiting time distribution analyses, which reflect whether the underlying distribution arises from a random or a memory-bearing process. The results show that, in the majority of the cases, the distributions of grand minima and maxima reveal that the nature of these events originates from memoryless processes. We also found that in our simulations the meridional circulation speed tends to be smaller during grand maximum, while it is faster during grand minimum periods. The radial differential rotation tends to be larger during grand maxima, while it is smaller during grand minima. The latitudinal differential rotation, on the other hand, is found to be larger during grand minima.

  1. Interplanetary transport of solar near-relativistic electrons on 2014 August 1 over a narrow range of heliolongitudes

    Directory of Open Access Journals (Sweden)

    Pacheco Daniel

    2017-01-01

    Full Text Available We study two consecutive solar near-relativistic (>50 keV electron events observed on 2014 August 1 by both STEREO spacecraft with a longitudinal separation of only about 35°. The events were unambiguously associated with a solar source location and not accompanied by type II radio bursts or coronal mass ejections. Despite their close location, the two spacecraft were embedded in different solar wind streams and the electron intensities observed by the two STEREOs showed clear differences in onset times, peak intensities and pitch-angle distributions. The apparently better connected spacecraft, STEREO B, observed a smaller and more isotropic intensity increase and a later event onset time than STEREO A. Since the interplanetary transport conditions of solar energetic particles (SEPs have a direct influence on the characteristics of the observed temporal profiles and the particle anisotropies at the spacecraft location, our aim is to understand if the observations on 2014 August 1 could be explained by different interplanetary transport conditions along each flux tube connecting the spacecraft with the solar source. For that purpose, we use a Monte Carlo interplanetary transport model combined with an inversion procedure to fit the in-situ observations of the two near-relativistic multi-spacecraft electron events. This allows us to obtain the injection profiles at the Sun and infer the transport conditions, which are characterized by the electron radial mean free path, λr. We obtain an almost simultaneous release of electrons for both spacecraft in both events. The release is consistent with the timing and duration of the type III radio burst emission and it is larger for STEREO B, the better connected spacecraft. In addition, we obtain different transport conditions in different solar wind streams. We find that the stream in which STEREO B was embedded was more diffusive (λr = 0.1AU for Event I and λr = 0.06AU for Event II than the

  2. Antimicrobial activity of Rauvolfia tetraphylla and Physalis minima ...

    African Journals Online (AJOL)

    GRACE

    2006-05-16

    May 16, 2006 ... The in vitro antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts were studied against ... Key words: Rauvolfia tetraphylla, Physalis minima, leaf, callus, extract, antimicrobial assay. INTRODUCTION ..... between peptides and inhibition of disease progression. Mol. Plant.

  3. Aquasols: on the role of secondary minima.

    Science.gov (United States)

    Hahn, Melinda W; Abadzic, Dean; O'Melia, Charles R

    2004-11-15

    Experiments are presented that test the hypothesis of deposition into and reentrainment from secondary minima during flow through porous media. The release of deposited particles following a decrease in ionic strength is inconsistent with deposition in the primary minimum of either simple DLVO interaction energy curves (which suggest that deposition is irreversible) or Born-DLVO interaction energy curves (which create a finite primary minimum that deepens with decreasing ionic strength). The observed release of particles is, on the other hand, consistent with deposition in the secondary minimum because this energy minimum decreases and can disappear with decreasing ionic strength. The implications for colloid transport of a reversible deposition process in the secondary minimum are very different from those of a process involving irreversible deposition in the primary minimum. First, particles that are continually captured and released will travel much farther in the subsurface than might be expected if the classic irreversible filtration model is applied. Second, and perhaps more significantly, deposition in the secondary well can increase with increasing particle size. Although particle transport by convective diffusion increases as particle size decreases, particle "attachment" in secondary minima decreases with decreasing particle size. Thus, smaller particles (those with diameters in the order of a few tens of nanometers) would be more effective in the facilitated transport of highly sorbing contaminants such as hydrophobic organic molecules, metals, and radionuclides. Other contaminants are themselves particles, such as viruses (tens of nanometers in diameter) and bacteria (near 1 microm in diameter). Due to this difference in size, viruses could be transported over much larger distances than bacteria. Third, the transport of colloids and, hence, the transport of contaminants associated with them, depends on the Hamaker constant of the particle

  4. On the Local Minima of the Order of Appearance Function

    Directory of Open Access Journals (Sweden)

    Florian Luca

    2015-01-01

    Full Text Available The order of appearance z(n of the positive integer n is the smallest positive integer k such that n divides Fk, the kth member of the Fibonacci sequence. In this paper, we improve upon some results from (Marques, 2011 concerning local minima of z(n.

  5. Optimizer convergence and local minima errors and their clinical importance

    International Nuclear Information System (INIS)

    Jeraj, Robert; Wu, Chuan; Mackie, Thomas R

    2003-01-01

    Two of the errors common in the inverse treatment planning optimization have been investigated. The first error is the optimizer convergence error, which appears because of non-perfect convergence to the global or local solution, usually caused by a non-zero stopping criterion. The second error is the local minima error, which occurs when the objective function is not convex and/or the feasible solution space is not convex. The magnitude of the errors, their relative importance in comparison to other errors as well as their clinical significance in terms of tumour control probability (TCP) and normal tissue complication probability (NTCP) were investigated. Two inherently different optimizers, a stochastic simulated annealing and deterministic gradient method were compared on a clinical example. It was found that for typical optimization the optimizer convergence errors are rather small, especially compared to other convergence errors, e.g., convergence errors due to inaccuracy of the current dose calculation algorithms. This indicates that stopping criteria could often be relaxed leading into optimization speed-ups. The local minima errors were also found to be relatively small and typically in the range of the dose calculation convergence errors. Even for the cases where significantly higher objective function scores were obtained the local minima errors were not significantly higher. Clinical evaluation of the optimizer convergence error showed good correlation between the convergence of the clinical TCP or NTCP measures and convergence of the physical dose distribution. On the other hand, the local minima errors resulted in significantly different TCP or NTCP values (up to a factor of 2) indicating clinical importance of the local minima produced by physical optimization

  6. Initial results of the evaluation of IRI hmF2 performance for minima 22–23 and 23–24

    Czech Academy of Sciences Publication Activity Database

    Araujo-Pradere, E. A.; Burešová, Dalia; Fuller-Rowell, D. J.; Fuller-Rowell, T. J.

    2013-01-01

    Roč. 51, č. 4 (2013), s. 630-638 ISSN 0273-1177 Grant - others:AV ČR(CZ) M100420901 Institutional support: RVO:68378289 Keywords : Solar minima * Ionosphere * hmF2 * IRI Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.238, year: 2013 http://www.sciencedirect.com/science/article/pii/S0273117712001093

  7. Observations of linear polarization in deep minima of WW Vul

    International Nuclear Information System (INIS)

    Grinin, V.P.; Kiselev, N.N.; Minikulov, N.Kh.; Chernova, G.P.; AN Tadzhikskoj SSR, Dushanbe. Inst. Astrofiziki)

    1988-01-01

    In the course of patrol photometric and polarimetric observations of WW Vul, initiated in 1986 in the Crimea and Sanglok, a broad photometrical minimum was registered, the deepest part of which being composed of three consecutive weakenings of brightness. The increase of linear polarization up to 5-6% (in V band) was observed in each of them. The analysis of the observational data shows, that the main part of polarized light occurs due to scattering of star radiation by dust particles of the circumstellar envelope. the contribution of this polarized radiation increases when the occultation of the star by the opaque dust cloud weakenes the direct (non-polarized) radiation of the star. Additional source of light polarization is the alignement of non-spherical particles in the dust cloud, which are responsible for occultation. Some arguments are given in favor to the idea, that the asymmetry axis of the circumstellar disc - like envelope of WW Vul is oriented parallel to the local interstellar magnetic field. If and alignment of non-spherical particles is caused by magnetic field of the disc, magnetic lines should follow the plane of the disc. The observations confirm the hypothesis, that the source of blue emission, observed in deep minima of such type stars, is the scattered radiation of circumstellar dust

  8. Distribution of benthic foraminifera within oxygen minima zone, off central west coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumder, A.; Henriques, P.J.; Nigam, R.

    and analyzed to study the effect of oxygen minima zone on benthic foraminiferal habitat. Benthic foraminifera were studied upto specific level of identification. However, to get a better picture, and keeping in mind that oxygen minima zone in the Arabian Sea...

  9. Multiple local minima in IMRT optimization based on dose-volume criteria

    International Nuclear Information System (INIS)

    Wu Qiuwen; Mohan, Radhe

    2002-01-01

    Multiple local minima traps are known to exist in dose-volume and dose-response objective functions. Nevertheless, their presence and consequences are not considered impediments in finding satisfactory solutions in routine optimization of IMRT plans using gradient methods. However, there is often a concern that a significantly superior solution may exist unbeknownst to the planner and that the optimization process may not be able to reach it. We have investigated the soundness of the assumption that the presence of multiple minima traps can be ignored. To find local minima, we start the optimization process a large number of times with random initial intensities. We investigated whether the occurrence of local minima depends upon the choice of the objective function parameters and the number of variables and whether their existence is an impediment in finding a satisfactory solution. To learn about the behavior of multiple minima, we first used a symmetric cubic phantom containing a cubic target and an organ-at-risk surrounding it to optimize the beam weights of two pairs of parallel-opposed beams using a gradient technique. The phantom studies also served to test our software. Objective function parameters were chosen to ensure that multiple minima would exist. Data for 500 plans, optimized with random initial beam weights, were analyzed. The search process did succeed in finding the local minima and showed that the number of minima depends on the parameters of the objective functions. It was also found that the consequences of local minima depended on the number of beams. We further searched for the multiple minima in intensity-modulated treatment plans for a head-and-neck case and a lung case. In addition to the treatment plan scores and the dose-volume histograms, we examined the dose distributions and intensity patterns. We did not find any evidence that multiple local minima affect the outcome of optimization using gradient techniques in any clinically

  10. Positions of the magnetoroton minima in the fractional quantum Hall effect

    Science.gov (United States)

    Balram, Ajit C.; Pu, Songyang

    2017-06-01

    The multitude of excitations of the fractional quantum Hall state are very accurately understood, microscopically, as excitations of composite fermions across their Landau-like Λ levels. In particular, the dispersion of the composite fermion exciton, which is the lowest energy spin conserving neutral excitation, displays filling-factor-specific minima called "magnetoroton" minima. Simon and Halperin employed the Chern-Simons field theory of composite fermions [Phys. Rev. B 48, 17368 (1993)] to predict the magnetoroton minima positions. Recently, Golkar et al. [Phys. Rev. Lett. 117, 216403 (2016)] have modeled the neutral excitations as deformations of the composite fermion Fermi sea, which results in a prediction for the positions of the magnetoroton minima. Using methods of the microscopic composite fermion theory we calculate the positions of the roton minima for filling factors up to 5/11 along the sequence s/ (2 s + 1) and find them to be in reasonably good agreement with both the Chern-Simons field theory of composite fermions and Golkar et al.'s theory. We also find that the positions of the roton minima are insensitive to the microscopic interaction in agreement with Golkar et al.'s theory. As a byproduct of our calculations, we obtain the charge and neutral gaps for the fully spin polarized states along the sequence s/ (2 s ± 1) in the lowest Landau level and the n = 1 Landau level of graphene.

  11. Jihadism, Narrow and Wide

    DEFF Research Database (Denmark)

    Sedgwick, Mark

    2015-01-01

    The term “jihadism” is popular, but difficult. It has narrow senses, which are generally valuable, and wide senses, which may be misleading. This article looks at the derivation and use of “jihadism” and of related terms, at definitions provided by a number of leading scholars, and at media usage....... It distinguishes two main groups of scholarly definitions, some careful and narrow, and some appearing to match loose media usage. However, it shows that even these scholarly definitions actually make important distinctions between jihadism and associated political and theological ideology. The article closes...

  12. Correlates of Narrow Bracketing

    DEFF Research Database (Denmark)

    Koch, Alexander; Nafziger, Julia

    We examine whether different phenomena of narrow bracketing can be traced back to some common characteristic and whether and how different phenomena are related. We find that making dominated lottery choices or ignoring the endowment when making risky choices are related phenomena and are both as...

  13. Polar cap magnetic field reversals during solar grand minima: could pores play a role?

    Czech Academy of Sciences Publication Activity Database

    Švanda, Michal; Brun, A.S.; Roudier, T.; Jouve, L.

    2016-01-01

    Roč. 586, February (2016), A123/1-A123/11 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GA14-04338S Institutional support: RVO:67985815 Keywords : dynamo * Sun * magnetic fields Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  14. Time spans between price maxima and price minima in stock markets

    Science.gov (United States)

    Zou, Yongjie; Li, Honggang

    2014-02-01

    We empirically investigate the distribution of time spans between price maxima and price minima in international stock markets, where a time span is defined as the time interval between a local price minimum and a local price maximum, and local price extrema are identified by a method introduced by Preis and Stanley (Preis et al. (2011), Preis (2011), Preis and Stanley (2011, 2010), Preis (2010), Preis and Stanley (2010), Stanley et al. (2010), Preis and Stanley (2009)). The empirical results show that both the tail distributions of time spans from local price maxima to local price minima and the tail distributions of time spans from local price minima to local price maxima yield an exponential distribution. In addition, price rise/fall asymmetry is observed by comparing the values of the exponents of the distribution curves. These results are robust across eight representative stock markets.

  15. THREE-DIMENSIONAL EVOLUTION OF SOLAR WIND DURING SOLAR CYCLES 22–24

    International Nuclear Information System (INIS)

    Manoharan, P. K.

    2012-01-01

    This paper presents an analysis of three-dimensional evolution of solar wind density turbulence and speed at various levels of solar activity between solar cycles 22 and 24. The solar wind data used in this study have been obtained from the interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope, operating at 327 MHz. Results show that (1) on average, there was a downward trend in density turbulence from the maximum of cycle 22 to the deep minimum phase of cycle 23; (2) the scattering diameter of the corona around the Sun shrunk steadily toward the Sun, starting from 2003 to the smallest size at the deepest minimum, and it corresponded to a reduction of ∼50% in the density turbulence between the maximum and minimum phases of cycle 23; (3) the latitudinal distribution of the solar wind speed was significantly different between the minima of cycles 22 and 23. At the minimum phase of solar cycle 22, when the underlying solar magnetic field was simple and nearly dipole in nature, the high-speed streams were observed from the poles to ∼30° latitudes in both hemispheres. In contrast, in the long-decay phase of cycle 23, the sources of the high-speed wind at both poles, in accordance with the weak polar fields, occupied narrow latitude belts from poles to ∼60° latitudes. Moreover, in agreement with the large amplitude of the heliospheric current sheet, the low-speed wind prevailed in the low- and mid-latitude regions of the heliosphere. (4) At the transition phase between cycles 23 and 24, the high levels of density and density turbulence were observed close to the heliospheric equator and the low-speed solar wind extended from the equatorial-to-mid-latitude regions. The above results in comparison with Ulysses and other in situ measurements suggest that the source of the solar wind has changed globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has been significantly reduced

  16. Nepenthes minima (Nepenthaceae), a new pyrophytic grassland species from Sulawesi, Indonesia

    NARCIS (Netherlands)

    Cheek, M.; Jebb, M.H.P.

    2016-01-01

    Nepenthes minima is the first known pyrophytic grassland Nepenthes species from outside Indochina and the Philippines. A member of the sect. Regiae (Borneo, Wallacea, New Guinea) it is restricted to the highland grasslands of Central Sulawesi (Celebes) and has close affinities with Nepenthes maxima.

  17. Learning behavior and temporary minima of two-layer neural networks

    NARCIS (Netherlands)

    Annema, Anne J.; Hoen, Klaas; Hoen, Klaas; Wallinga, Hans

    1994-01-01

    This paper presents a mathematical analysis of the occurrence of temporary minima during training of a single-output, two-layer neural network, with learning according to the back-propagation algorithm. A new vector decomposition method is introduced, which simplifies the mathematical analysis of

  18. A new heuristic method for approximating the number of local minima in partial RNA energy landscapes.

    Science.gov (United States)

    Albrecht, Andreas A; Day, Luke; Abdelhadi Ep Souki, Ouala; Steinhöfel, Kathleen

    2016-02-01

    The analysis of energy landscapes plays an important role in mathematical modelling, simulation and optimisation. Among the main features of interest are the number and distribution of local minima within the energy landscape. Granier and Kallel proposed in 2002 a new sampling procedure for estimating the number of local minima. In the present paper, we focus on improved heuristic implementations of the general framework devised by Granier and Kallel with regard to run-time behaviour and accuracy of predictions. The new heuristic method is demonstrated for the case of partial energy landscapes induced by RNA secondary structures. While the computation of minimum free energy RNA secondary structures has been studied for a long time, the analysis of folding landscapes has gained momentum over the past years in the context of co-transcriptional folding and deeper insights into cell processes. The new approach has been applied to ten RNA instances of length between 99 nt and 504 nt and their respective partial energy landscapes defined by secondary structures within an energy offset ΔE above the minimum free energy conformation. The number of local minima within the partial energy landscapes ranges from 1440 to 3441. Our heuristic method produces for the best approximations on average a deviation below 3.0% from the true number of local minima. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Checklist of insects associated with Salvinia minima (Baker) in Louisiana, USA

    Science.gov (United States)

    his study presents a list of adult insects (excluding Diptera and Lepidoptera) collected from an infestation of an invasive aquatic weed, common salvinia (Salvinia minima Baker), in southern Louisiana, USA. Insects were sampled from May – November of 2009 and 2010 using floating pitfall traps. A to...

  20. Minima of interannual sea-level variability in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Shankar, D.; Aparna, S.G.; McCreary, J.P.; Suresh, I.; Neetu, S.; Durand, F.; Shenoi, S.S.C.; Al Saafani, M.A.

    , the adjustment time scale of the system is less than that of the forcing, leading to a quasi-steady balance, a property that distinguishes the interannual minima from those at annual and semiannual time scales. Idealized solutions show that the presence of India...

  1. Spontaneous Detachment of Colloids from Primary Energy Minima by Brownian Diffusion.

    Directory of Open Access Journals (Sweden)

    Zhan Wang

    Full Text Available The Derjaguin-Landau-Verwey-Overbeek (DLVO interaction energy profile has been frequently used to interpret the mechanisms controlling colloid attachment/detachment and aggregation/disaggregation behavior. This study highlighted a type of energy profile that is characterized by a shallow primary energy well (i.e., comparable to the average kinetic energy of a colloid at a small separation distance and a monotonic decrease of interaction energy with separation distance beyond the primary energy well. This energy profile is present due to variations of height, curvature, and density of discrete physical heterogeneities on collector surfaces. The energy profile indicates that colloids can be spontaneously detached from the shallow primary energy well by Brownian diffusion. The spontaneous detachment from primary minima was unambiguously confirmed by conducting laboratory column transport experiments involving flow interruptions for two model colloids (polystyrene latex microspheres and engineered nanoparticles (fullerene C60 aggregates. Whereas the spontaneous detachment has been frequently attributed to attachment in secondary minima in the literature, our study indicates that the detached colloids could be initially attached at primary minima. Our study further suggests that the spontaneous disaggregation from primary minima is more significant than spontaneous detachment because the primary minimum depth between colloid themselves is lower than that between a colloid and a collector surface.

  2. Spontaneous Detachment of Colloids from Primary Energy Minima by Brownian Diffusion.

    Science.gov (United States)

    Wang, Zhan; Jin, Yan; Shen, Chongyang; Li, Tiantian; Huang, Yuanfang; Li, Baoguo

    2016-01-01

    The Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy profile has been frequently used to interpret the mechanisms controlling colloid attachment/detachment and aggregation/disaggregation behavior. This study highlighted a type of energy profile that is characterized by a shallow primary energy well (i.e., comparable to the average kinetic energy of a colloid) at a small separation distance and a monotonic decrease of interaction energy with separation distance beyond the primary energy well. This energy profile is present due to variations of height, curvature, and density of discrete physical heterogeneities on collector surfaces. The energy profile indicates that colloids can be spontaneously detached from the shallow primary energy well by Brownian diffusion. The spontaneous detachment from primary minima was unambiguously confirmed by conducting laboratory column transport experiments involving flow interruptions for two model colloids (polystyrene latex microspheres) and engineered nanoparticles (fullerene C60 aggregates). Whereas the spontaneous detachment has been frequently attributed to attachment in secondary minima in the literature, our study indicates that the detached colloids could be initially attached at primary minima. Our study further suggests that the spontaneous disaggregation from primary minima is more significant than spontaneous detachment because the primary minimum depth between colloid themselves is lower than that between a colloid and a collector surface.

  3. On the minima of the time integrated perturbation factor in the Scherer-Blume theory

    International Nuclear Information System (INIS)

    Silveira, E.F. da; Freire Junior, F.L.; Massolo, C.P.; Schaposnik, F.A.

    1981-09-01

    The minima in the correlation time dependence of the Scherer-Blume time integrated attenuation coefficients for the hyperfine perturbation of ions recoiling in gas are studied. Its position and depth are determined for different physical situations and comparison with experimental data is shown. (Author) [pt

  4. Narrow, duplicated internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  5. Dust around young stars. Observations of the polarization of UX Ori in deep minima

    International Nuclear Information System (INIS)

    Voshchinnikov, N.V.; Grinin, V.P.; Kiselev, N.N.; Minikulov, N.K.

    1988-01-01

    Photometric and polarimetric monitoring observations of UX Ori begun in 1986 in the Crimea and Bolivia have resulted in the observation of two deep minima of the brightness during which a growth of the linear polarization (to ≅7%) was observed, together with a tendency for the circular polarization to increase (up to ≅1%). Analysis of the observational data shows that the main source of the polarized radiation in the deep minima is the emission of the star scattered by grains of circumstellar dust. On the basis of Mie's theory for a polydisperse graphite-silicate mixtures of particles the optical properties of ellipsoidal dust envelopes have been calculated and a model of the Algol-like minimum constructed

  6. Molecular characterization of a new begomovirus infecting a leguminous weed Rhynchosia minima in India.

    Science.gov (United States)

    Jyothsna, P; Rawat, Ramaveer; Malathi, V G

    2011-06-01

    A begomovirus associated with yellow mosaic disease in Rhynchosia minima, a common weed was cloned and sequenced. The virus has a bipartite genome, of which DNA-A is 2727 nucleotide length, and DNA-B 2679 nucleotides, and has a typical Old World bipartite begomovirus genome organization. Sequence comparison to all other begomovirus sequences available in the database shows the virus isolated from R. minima to be distinct. Maximum identity of 84% was seen with an isolate of Velvet bean severe mosaic virus-(India: Lucknow:2009) VBSMV-(IN:Luc:09) (GeneBank Accession No. FN543425), while less than 73% identity was observed with any other legumovirus. The molecular data show that the virus identified here is a new species in the genus Begomovirus for which the name Rhynchosia yellow mosaic India virus is proposed.

  7. Calculation of the similarity rate between images based on the local minima present Therein

    Directory of Open Access Journals (Sweden)

    K. Hourany

    2016-12-01

    Full Text Available Hourany, K., Benmeddour, F., Moulin, E., Assaad, J. and Zaatar, Y. Calculation of the similarity rate between images based on the local minima present therein. 2016. Lebanese Science Journal, 17(2: 177-192. Image processing is a very vast field that includes both IT and applied mathematics. It is a discipline that studies the improvement and transformations of digital images hence permitting the improvement of the quality of these images and the extraction of information. The comparison of digital images is a paramount issue that has been discussed in several researches because of its various applications especially in the field of control and surveillance such as the Structural Health Monitoring using acoustic waves. The IT support of the images serves especially for comparing them notably in distinguishing differences between these images and quantifying them automatically. In this study we will present an algorithm, allowing us to calculate the similarity rate between images based on the local minima present therein. This algorithm is divided into two main parts. In the first part we will explain how to extract the local minima from an image and in the second part we will show how to calculate the similarity rate between two images.

  8. Generating true minima in constrained variational formulations via modified Lagrange multipliers.

    Science.gov (United States)

    Solis, Francisco J; Jadhao, Vikram; Olvera de la Cruz, Monica

    2013-11-01

    Variational principles are important in the investigation of large classes of physical systems. They can be used both as analytical methods as well as starting points for the formulation of powerful computational techniques such as dynamical optimization methods. Systems with charged objects in dielectric media and systems with magnetically active particles are important examples. In these examples and other important cases, the variational principles describing the system are required to obey a number of constraints. These constraints are implemented within the variational formulation by means of Lagrange multipliers. Such constrained variational formulations are in general not unique. For the application of efficient simulation methods, one must find specific formulations that satisfy a number of important conditions. An often required condition is that the functional be positive-definite, in other words, its extrema be actual minima. In this article, we present a general approach to attack the problem of finding, among equivalent variational functionals, those that generate true minima. The method is based on the modification of the Lagrange multiplier which allows us to generate large families of effective variational formulations associated with a single original constrained variational principle. We demonstrate its application to different examples and, in particular, to the important cases of Poisson and Poisson-Boltzmann equations. We show how to obtain variational formulations for these systems with extrema that are always minima.

  9. VizieR Online Data Catalog: UY UMa and EF Boo compiled time of minima (Yu+, 2017)

    Science.gov (United States)

    Yu, Y.-X.; Zhang, X.-D.; Hu, K.; Xiang, F.-Y.

    2017-11-01

    In order to construct the (O-C) diagram to analyze the period change of UY UMa, we have performed a careful search for all available times of light minima. A total of 76 times of light minima were collected and listed in Table 2. >From the literatures and two well-known databases (i.e., the O-C gateway (http://var.astro.cz/ocgate) and the Lichtenknecker database of the BAV (http://www.bav-astro.de/LkDB/index.php)), we have collected a total of 75 available times of light minima for EF Boo, which are summarized in Table 3. (3 data files).

  10. Solar Field Mapping and Dynamo Behavior

    Directory of Open Access Journals (Sweden)

    Kenneth H. Schatten

    2012-01-01

    Full Text Available We discuss the importance of the Sun’s large-scale magnetic field to the Sun-Planetary environment. This paper narrows its focus down to the motion and evolution of the photospheric large-scale magnetic field which affects many environments throughout this region. For this purpose we utilize a newly developed Netlogo cellular automata model. The domain of this algorithmic model is the Sun’s photosphere. Within this computational space are placed two types of entities or agents; one may refer to them as bluebirds and cardinals; the former carries outward magnetic flux and the latter carries out inward magnetic flux. One may simply call them blue and red agents. The agents provide a granularity with discrete changes not present in smooth MHD models; they undergo three processes: birth, motion, and death within the photospheric domain. We discuss these processes, as well as how we are able to develop a model that restricts its domain to the photosphere and allows the deeper layers to be considered only through boundary conditions. We show the model’s ability to mimic a number of photospheric magnetic phenomena: the solar cycle (11-year oscillations, the Waldmeier effect, unipolar magnetic regions (e.g. sectors and coronal holes, Maunder minima, and the march/rush to the poles involving the geometry of magnetic field reversals. We also discuss why the Sun sometimes appears as a magnetic monopole, which of course requires no alteration of Maxwell’s equations.

  11. Early Eocene carbon isotope excursions and landscape destabilization at eccentricity minima: Green River Formation of Wyoming

    Science.gov (United States)

    Smith, M. Elliot; Carroll, Alan R.; Scott, Jennifer J.; Singer, Brad S.

    2014-10-01

    Repeated global reorganizations of carbon cycling and biotic, oceanic and terrestrial processes occurred during the Early Eocene, and appear to have been paced by cyclic variations in the eccentricity of the Earth's orbit. The phase relationship(s) between insolation variation, terrestrial paleoclimate, and atmospheric pCO2 during these events remains enigmatic however, due to their poorly constrained timing relative to specific orbital configurations. Here we use tiered interpolation between radioisotopic ages and paleomagnetic polarity chrons to compare high-resolution δ13C and lithofacies records from the Wilkins Peak Member of the Green River Formation of western North America to a Fe-intensity XRF record from the western Atlantic Ocean, and to numerical solutions for Earth's orbital configuration. Wilkins Peak Member lithofacies stacking patterns record cyclic geomorphic responses to insolation and climate fluctuations, spanning an interval of 1.8 Ma. Previous macrostratigraphic analyses using 40Ar/39Ar and U-Pb ash bed ages indicate that these cycles reflect long and short eccentricity modulation of precession. Hydrologic variance appears to have occurred inversely with intervals of maximum sediment advection, with carbonate- and evaporite-dominated lacustrine modes during eccentricity maxima, and siliciclastic-dominated alluvial modes during eccentricity minima. Stable carbon isotope analyses of 126 meters of Wilkins Peak Member strata reveal a regular ∼5 per mil oscillation between high-δ13C lacustrine modes and low-δ13C alluvial modes. Tiered interpolation between paleomagnetically characterized terrestrial ash beds facilitates the integration of 11 radioisotopic ages with the geomagnetic polarity timescale, resulting in significant expansion of chron C23 and shortening of chron C22 relative to timescales based on seafloor magnetic anomaly profiles. The new proposed timescale permits direct comparison of terrestrial and marine climate proxy records

  12. Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root.

    Science.gov (United States)

    Jia, Xuejing; Zhang, Chao; Hu, Jie; He, Muxue; Bao, Jiaolin; Wang, Kai; Li, Peng; Chen, Meiwan; Wan, Jianbo; Su, Huanxing; Zhang, Qingwen; He, Chengwei

    2015-11-23

    Box-Behnken design (BBD), one of the most common response surface methodology (RSM) methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM). The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95%±0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries.

  13. Supercritical fluid extraction assisted isolation of sesquiterpene lactones with antiproliferative effects from Centipeda minima.

    Science.gov (United States)

    Wu, Peng; Su, Miao-Xian; Wang, Ying; Wang, Guo-Cai; Ye, Wen-Cai; Chung, Hau-Yin; Li, Juan; Jiang, Ren-Wang; Li, Yao-Lan

    2012-04-01

    Pseudoguaianolide sesquiterpene lactones minimolides A (1), B (2), C (3) and D (4) and two guaianolide sesquiterpene lactones minimolides E (5) and F (6), along with seven known ones (7-13), were isolated from the supercritical fluid extract of Centipeda minima. The structures of these compounds were elucidated by extensive spectroscopic methods (IR, UV, HRESIMS, 1D-NMR and 2D-NMR), and the complete structure and stereochemistry of 1 was further confirmed by X-ray diffraction analysis. Compounds 1, 5-8,11 and 13 displayed inhibitory activity against human nasopharyngeal cancer cells (CNE) with IC(50) values ranging from 1.1 to 20.3 μM. Compound 13 containing both α-methylene-γ-lactone and α, β-unsaturated cyclopentenone moieties exhibited even stronger inhibitory activity than that of cisplatin (positive control) through cell cycle arrest at G2/M phase. Isolation of six sesquiterpene lactones from Centipeda minima highlighted the potential of supercritical fluid extraction for enrichment of minor constituents for phytochemical study. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root

    Directory of Open Access Journals (Sweden)

    Xuejing Jia

    2015-11-01

    Full Text Available Box-Behnken design (BBD, one of the most common response surface methodology (RSM methods, was used to optimize the experimental conditions for ultrasound-assisted extraction of polysaccharides from Rhynchosia minima root (PRM. The antioxidant abilities and anticancer activity of purified polysaccharide fractions were also measured. The results showed that optimal extraction parameters were as follows: ultrasound exposure time, 21 min; ratio of water to material, 46 mL/g; ultrasound extraction temperature, 63 °C. Under these conditions, the maximum yield of PRM was 16.95% ± 0.07%. Furthermore, the main monosaccharides of purified fractions were Ara and Gal. PRM3 and PRM5 exhibited remarkable DPPH radical scavenging activities and reducing power in vitro. PRM3 showed strong inhibitory activities on the growth of MCF-7 cells in vitro. The above results indicate that polysaccharides from R. minima root have the potential to be developed as natural antioxidants and anticancer ingredients for the food and pharmaceutical industries.

  15. Anomalous Arctic surface wind patterns and their impacts on September sea ice minima and trend

    Directory of Open Access Journals (Sweden)

    Bingyi Wu

    2012-05-01

    Full Text Available We used monthly mean surface wind data from the National Centers for Environmental Prediction/National Centers for Atmospheric Research (NCEP/NCAR reanalysis dataset during the period 1979–2010 to describe the first two patterns of Arctic surface wind variability by means of the complex vector empirical orthogonal function (CVEOF analysis. The first two patterns respectively account for 31 and 16% of its total anomalous kinetic energy. The leading pattern consists of the two subpatterns: the northern Laptev Sea (NLS pattern and the Arctic dipole (AD pattern. The second pattern contains the northern Kara Sea (NKS pattern and the central Arctic (CA pattern. Over the past two decades, the combined dynamical forcing of the first two patterns has contributed to Arctic September sea ice extent (SIE minima and its declining trend. September SIE minima are mainly associated with the negative phase of the AD pattern and the positive phase of the CA pattern during the summer (July to September season, and both phases coherently show an anomalous anticyclone over the Arctic Ocean. Wind patterns affect September SIE through their frequency and intensity. The negative trend in September SIE over the past two decades is associated with increased frequency and enhanced intensity of the CA pattern during the melting season from April to September. Thus, it cannot be simply attributed to the AD anomaly characterised by the second empirical orthogonal function mode of sea level pressure north of 70°N. The CA pattern exhibited interdecadal variability in the late 1990s, and an anomalous cyclone prevailed before 1997 and was then replaced by an anomalous anticyclone over the Arctic Ocean that is consistent with the rapid decline trend in September SIE. This paper provides an alternative way to identify the dominant patterns of climate variability and investigate their associated Arctic sea ice variability from a dynamical perspective. Indeed, this study

  16. Fusion process of Lennard-Jones clusters: global minima and magic numbers formation

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2004-01-01

    measured for the clusters of noble gas atoms. Our method serves as an efficient alternative to the global optimization techniques based on the Monte-Carlo simulations and it can be applied for the solutions of a broad variety of problems in which atomic cluster structure is important.......We present a new theoretical framework for modeling the fusion process of Lennard–Jones (LJ) clusters. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system and absorbing its energy at each step, we find cluster growing paths up to the cluster size of 150 atoms....... We demonstrate that in this way all known global minima structures of the (LJ)-clusters can be found. Our method provides an efficient tool for the calculation and analysis of atomic cluster structure. With its use we justify the magic number sequence for the clusters of noble gas atoms and compare...

  17. A strategy for finding classes of minima on a hypersurface: implications for approaches to the protein folding problem.

    Science.gov (United States)

    Head-Gordon, T; Stillinger, F H; Arrecis, J

    1991-12-15

    Locating the native structure of a given protein is a task made difficult by the complexity of the potential energy hypersurface and by the huge number of local minima it contains. We have explored a strategy (the "antlion" method) for hypersurface modification that suppresses all minima but that of the native structure. Transferrable penalty functions with general applicability for modifying a hypersurface to retain the desired minimum are identified, and two blocked oligopeptides (alanine dipeptide and tetrapeptide) are used for specific numerical illustration of the dramatic simplification that ensues. In addition, an intermediary role for neural networks to manage some aspects of the antlion strategy applied to large polypeptides and proteins is introduced.

  18. Quantification of methyl esters of fatty acids in the oil of Physalis minima by GC-MS

    Directory of Open Access Journals (Sweden)

    Muhammad Nasimullah Qureshi

    2015-02-01

    Full Text Available Objective: To investigate quantification of methyl esters of fatty acids in the oil extracted from Physalis minima (P. minima using gas chromatography-mass spectrometer. Methods: Oil was extracted from the shade dried plant with n-hexane through Soxhlet extraction. Fatty acids that present in the oil were derivatized to fatty acid methyl esters and analysed through gas chromatography-mass spectrometer. Results: A total of nine fatty acids were detected in quantifiable amount in the oil. Both the saturated fatty acids and unsaturated fatty acids were identified. Palmitic acid was found in the highest concentration as 46.83%. Linoleic acid (ω-6 and linolenic acid (ω-3 were obtained in appreciable amount as 16.98% and 14.80% respectively among the unsaturated fatty acids in the oil under study. From the literature review, it appeared that fatty acids were determined for the first time in the oil of P. minima. Conclusions: Presence of these important fatty acids in high amount makes P. minima oil beneficial for health, which can be used in the preparation of phytopharmaceutical or pharmaceutical preparations. Moreover, the results of this study are useful for the phytopharmaceutical industries to establish their quality control profile.

  19. Processes controlling mid-water column oxygen minima over the Texas-Louisiana shelf

    Science.gov (United States)

    Zhang, Wenxia; Hetland, Robert D.; DiMarco, Steven F.; Fennel, Katja

    2015-04-01

    We investigate distributions of dissolved oxygen over the Texas-Louisiana shelf using spatially highly resolved observations in combination with a regional circulation model with simple oxygen dynamics. The observations were collected using a towed, undulating CTD during the Mechanisms Controlling Hypoxia (MCH) program. Mid-water oxygen minimum layers (dissolved oxygen lower than 3.2 mL L-1) were detected in many transects. These oxygen minimum layers are connected with the bottom boundary layer and follow the pycnocline seaward as a tongue of low oxygen into the mid-water column. T-S diagrams highlighting the low oxygen minima in both observations and simulations imply direct connections between low-oxygen bottom water and the oxygen minimum layer. The dynamics of these oxygen minimum layers in the mid-water column are examined using a three-dimensional hydrodynamic model, based on the Regional Ocean Modeling System (ROMS). Convergence within the bottom boundary layer relative to density surfaces is calculated, results show that there is a convergence in the bottom boundary layer at the location where the pycnocline intersects the bottom. Buoyancy advection forced by bottom Ekman transport creates this convergent flow, and the corresponding low-oxygen intrusion. Similar intrusions of near-bottom water into the pycnocline are observed in other regions. The presence of hypoxia within the bottom boundary layer in the northern Gulf of Mexico creates a unique situation in which these intrusions are also associated with low dissolved oxygen.

  20. Using vibrational Cooper minima to determine strong-field molecular-dissociation pathways

    Science.gov (United States)

    Severt, T.; Zohrabi, M.; Armstrong, G. S. J.; McKenna, J.; Gaire, B.; Kling, Nora G.; Ablikim, U.; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.

    2015-05-01

    We explore the possibility of using vibrational ``Cooper minima'' (VCM) locations as a method to determine dissociation pathways of molecules in a strong laser field. As a test case, we study the laser-induced dissociation of an O2+ion beam by several wavelengths (λ = 800 , 400, and 266 nm) using a coincidence three-dimensional momentum imaging technique. Vibrational structure is observed in the kinetic energy release spectra, revealing a suppression of the dissociation of certain vibrational levels, which is a manifestation of the VCM effect. Previously, it has been shown in H2+that first-order time-dependent perturbation theory can be used to predict the locations of the VCM. We explore if the VCM locations predicted by perturbation theory can help uniquely identify dissociation pathways in O2+and consider its utility for other systems. Supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. TS was partially supported by NSF-REU under Grant No. PHY-0851599.

  1. Flotation Bubble Delineation Based on Harris Corner Detection and Local Gray Value Minima

    Directory of Open Access Journals (Sweden)

    Weixing Wang

    2015-03-01

    Full Text Available Froth image segmentation is an important and basic part in an online froth monitoring system in mineral processing. The fast and accurate bubble delineation in a froth image is significant for the subsequent froth surface characterization. This paper proposes a froth image segmentation method combining image classification and image segmentation. In the method, an improved Harris corner detection algorithm is applied to classify froth images first. Then, for each class, the images are segmented by automatically choosing the corresponding parameters for identifying bubble edge points through extracting the local gray value minima. Finally, on the basis of the edge points, the bubbles are delineated by using a number of post-processing functions. Compared with the widely used Watershed algorithm and others for a number of lead zinc froth images in a flotation plant, the new method (algorithm can alleviate the over-segmentation problem effectively. The experimental results show that the new method can produce good bubble delineation results automatically. In addition, its processing speed can also meet the online measurement requirements.

  2. Leaching of lead by ammonium salts and EDTA from Salvinia minima biomass produced during aquatic phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Lopez, Roberto Aurelio [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo Qro., 76700 Mexico (Mexico)], E-mail: ndahi2000@yahoo.com; Meas, Yunny [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo Qro., 76700 Mexico (Mexico)], E-mail: yunnymeas@cideteq.mx; Citlalli Gama, Silvia; Ortega Borges, Raul [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo Qro., 76700 Mexico (Mexico); Olguin, Eugenia J. [Instituto de Ecologia (INECOL), Apdo. Postal 63, Xalapa, Veracruz 91000 (Mexico)

    2008-06-15

    Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of lead (Pb) from Salvinia minima biomass was studied by testing water, several aqueous ammonium salts, and EDTA solution as lead extractants. The research was carried out in two phases: (i) a leaching study to determine the lead-extraction efficiency of the different leachants, and (ii) a thermodynamic analysis to identify the likely reactions and stable Pb(II) species formed in the leaching systems of the most efficient leachants. Experimentally, lead concentrations measured in leached biomass and in leachates were significantly different among the various leachants. It was determined that the extraction strength of the leachants followed the order: EDTA > ammonium oxalate > water {approx} ammonium nitrate > ammonium acetate, achieving Pb extraction efficiencies of 99%, 70%, 7.2%, 6.9% and 1.3%, respectively, in single-stage extractions. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species PbEDTA{sup 2-} for EDTA system, and the insoluble Pb(COO){sub 2S} precipitate for the oxalate system.

  3. Solar forcing of climate during the last millennium recorded in lake sediments from northern Sweden

    DEFF Research Database (Denmark)

    Kokfelt, Ulla; Muscheler, Raimund

    2013-01-01

    century. Periods of low solar activity are associated with minima in minerogenic material and vice versa. A comparison between the sunspot cycle and a long instrumental series of summer precipitation further reveals a link between the 11-year solar cycle and summer precipitation variability since around...

  4. Are both symmetric and buckled dimers on Si(100) minima? Density functional and multireference perturbation theory calculations

    International Nuclear Information System (INIS)

    Jung, Yousung; Shao, Yihan; Gordon, Mark S.; Doren, Douglas J.; Head-Gordon, Martin

    2003-01-01

    We report a spin-unrestricted density functional theory (DFT) solution at the symmetric dimer structure for cluster models of Si(100). With this solution, it is shown that the symmetric structure is a minimum on the DFT potential energy surface, although higher in energy than the buckled structure. In restricted DFT calculations the symmetric structure is a saddle point connecting the two buckled minima. To further assess the effects of electron correlation on the relative energies of symmetric versus buckled dimers on Si(100), multireference second order perturbation theory (MRMP2) calculations are performed on these DFT optimized minima. The symmetric structure is predicted to be lower in energy than the buckled structure via MRMP2, while the reverse order is found by DFT. The implications for recent experimental interpretations are discussed

  5. The Solar Cycle

    Directory of Open Access Journals (Sweden)

    David H. Hathaway

    2015-09-01

    Full Text Available The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev–Ohl (even-odd Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24.

  6. Physalis minima Leaves Extract Induces Re-Endothelialization in Deoxycorticosterone Acetate-Salt-Induced Endothelial Dysfunction in Rats

    Directory of Open Access Journals (Sweden)

    Dian Nugrahenny

    2018-02-01

    Full Text Available The administration of deoxy-corticosterone acetate (DOCA-salt can induce oxidative stress leading to decrease the bioavailability of nitric oxide (NO, increase senescence of circulating endothelial progenitor cells (EPCs, thus contributing to endothelial dysfunction. This study was aimed to investigate the effects of Physalis minima L. leaves extract on serum NO levels, circulating EPCs number, and histopathology of tail artery endothelial cells in DOCA-salt-induced endothelial dysfunction in rats. Twenty-five male Wistar rats were randomly divided into five groups: rats without any treatment (normal, rats treated with DOCA (10 mg/kgBW s.c. twice weekly and given 0.9% NaCl to drink ad libitum for 6 weeks, and DOCA-salt-induced rats orally supplemented with P. minima leaves extract at doses of 500, 1500, or 2500 mg/kgBW for 4 weeks. Serum NO levels were measured by colorimetry. The number of circulating EPCs (CD34+/CD133+ cells was determined by flow cytometry. The tail artery sections were histologically processed with hematoxylin-eosin staining. DOCA-salt-induced rats showed significantly (p<0.05 decrease in serum NO levels and circulating EPCs number compared to the normal. There was also more detached tail artery endothelial cells in DOCA-salt-induced rats. P. minima leaves extract at a dose of 500 mg/kgBW significantly (p<0.05 increased serum NO level and circulating EPCs number, and also induced an optimal re-endothelialization in DOCA-salt-induced rats. P. minima leave extract dose-dependently increases NO bioavailability contributing to enhanced EPCs mobilization, thereby promoting re-endothelialization in DOCA-salt-induced endothelial dysfunction in rats.

  7. Regioregular narrow-bandgap-conjugated polymers for plastic electronics

    Science.gov (United States)

    Ying, Lei; Huang, Fei; Bazan, Guillermo C.

    2017-03-01

    Progress in the molecular design and processing protocols of semiconducting polymers has opened significant opportunities for the fabrication of low-cost plastic electronic devices. Recent studies indicate that field-effect transistors and organic solar cells fabricated using narrow-bandgap regioregular polymers with translational symmetries in the direction of the backbone vector often outperform those containing analogous regiorandom polymers. This review addresses the cutting edge of regioregularity chemistry, in particular how to control the spatial distribution in the molecular structures and how this order translates to more ordered bulk morphologies. The effect of regioregularity on charge transport and photovoltaic properties is also outlined.

  8. Narrow gap electronegative capacitive discharges

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

    2013-10-15

    Narrow gap electronegative (EN) capacitive discharges are widely used in industry and have unique features not found in conventional discharges. In this paper, plasma parameters are determined over a range of decreasing gap length L from values for which an electropositive (EP) edge exists (2-region case) to smaller L-values for which the EN region connects directly to the sheath (1-region case). Parametric studies are performed at applied voltage V{sub rf}=500 V for pressures of 10, 25, 50, and 100 mTorr, and additionally at 50 mTorr for 1000 and 2000 V. Numerical results are given for a parallel plate oxygen discharge using a planar 1D3v (1 spatial dimension, 3 velocity components) particle-in-cell (PIC) code. New interesting phenomena are found for the case in which an EP edge does not exist. This 1-region case has not previously been investigated in detail, either numerically or analytically. In particular, attachment in the sheaths is important, and the central electron density n{sub e0} is depressed below the density n{sub esh} at the sheath edge. The sheath oscillations also extend into the EN core, creating an edge region lying within the sheath and not characterized by the standard diffusion in an EN plasma. An analytical model is developed using minimal inputs from the PIC results, and compared to the PIC results for a base case at V{sub rf}=500 V and 50 mTorr, showing good agreement. Selected comparisons are made at the other voltages and pressures. A self-consistent model is also developed and compared to the PIC results, giving reasonable agreement.

  9. Quantum Dynamics Study of the Potential Energy Minima Effect on Energy Efficiency for the F- + CH3Cl → FCH3 + Cl- Reaction.

    Science.gov (United States)

    Li, Yida; Wang, Yuping; Wang, Dunyou

    2017-04-13

    The Polanyi rules on the energy efficiency on reactivity are summarized solely from the locations of barriers on the potential energy surfaces. Here, our quantum dynamics study for the F - + CH 3 Cl → FCH 3 + Cl - reaction shows that the two potential energy minima in the entrance channel on the potential energy surface play an essential role in energy efficiency on reactivity. The reactivity of this reaction is dominated by the low collision energies where two distinctive reaction mechanisms involve the two minima in the entrance channel. Overall, the Cl-CH 3 stretching motion and C-H 3 umbrella motion both are more efficient than the translational motion in promoting this reaction. Although this reaction has a negative energy barrier, our study shows that it is the minima in the entrance channel, together with the energy barrier relative to these minima, that determine the energy efficacy on reactivity.

  10. Comparison of PSF maxima and minima of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems

    International Nuclear Information System (INIS)

    Ratnam, Challa; Rao, Vadlamudi Lakshmana; Goud, Sivagouni Lachaa

    2006-01-01

    In the present paper, and a series of papers to follow, the Fourier analytical properties of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems are investigated. First, the transmission function for MACA and CMACA is derived using Fourier methods and, based on the Fresnel-Kirchoff diffraction theory, the formulae for the point spread function are formulated. The PSF maxima and minima are calculated for both the MACA and CMACA systems. The dependence of these properties on the number of zones is studied and reported in this paper

  11. Comparison of PSF maxima and minima of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems

    Science.gov (United States)

    Ratnam, Challa; Lakshmana Rao, Vadlamudi; Lachaa Goud, Sivagouni

    2006-10-01

    In the present paper, and a series of papers to follow, the Fourier analytical properties of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems are investigated. First, the transmission function for MACA and CMACA is derived using Fourier methods and, based on the Fresnel-Kirchoff diffraction theory, the formulae for the point spread function are formulated. The PSF maxima and minima are calculated for both the MACA and CMACA systems. The dependence of these properties on the number of zones is studied and reported in this paper.

  12. Comparison of PSF maxima and minima of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems

    Energy Technology Data Exchange (ETDEWEB)

    Ratnam, Challa [Physics Department, New Science College, Ameerpet, Hyderabad (India); Rao, Vadlamudi Lakshmana [Physics Department, New Science College, Ameerpet, Hyderabad (India); Goud, Sivagouni Lachaa [Department of Physics, Osmania University, Hyderabad (India)

    2006-10-07

    In the present paper, and a series of papers to follow, the Fourier analytical properties of multiple annuli coded aperture (MACA) and complementary multiple annuli coded aperture (CMACA) systems are investigated. First, the transmission function for MACA and CMACA is derived using Fourier methods and, based on the Fresnel-Kirchoff diffraction theory, the formulae for the point spread function are formulated. The PSF maxima and minima are calculated for both the MACA and CMACA systems. The dependence of these properties on the number of zones is studied and reported in this paper.

  13. Molecular characterisation and infectivity of a "Legumovirus" (genus Begomovirus: family Geminiviridae) infecting the leguminous weed Rhynchosia minima in Pakistan.

    Science.gov (United States)

    Ilyas, Muhammad; Qazi, Javaria; Mansoor, Shahid; Briddon, Rob W

    2009-11-01

    The legume yellow mosaic viruses (LYMVs) that cause extensive losses to grain legumes across southern Asia are an evolutionarily unusual group of begomoviruses (genus Begomovirus; family Geminiviridae) with bipartite genomes. All previously identified LYMVs were isolated from leguminous crop species. Here we have identified a virus related to the LYMVs in a common weed, the legume Rhynchosia minima originating from Pakistan. Analysis of the sequence of the virus shows it to be a typical bipartite begomovirus. Sequence comparisons to all other begomovirus sequences available in the databases show the virus from R. minima to be distinct, with the highest level of sequence identity (69.5%) to an isolate of Mungbean yellow mosaic virus. This indicates that the virus identified here is a new species in the genus Begomovirus for which we propose the name Rhynchosia yellow mosaic virus (RhYMV). By Agrobacterium-mediated inoculation we show that, in common with the other LYMVs, the clones of RhYMV are not infectious to the experimental host Nicotiana benthamiana. In soybean, the results of inoculation depended upon the variety. In soybean var. Ig6 the symptoms were mild and plants recovered from infection. However, in var. FS-85, symptoms were severe and progressed to necrosis, indicative of a hypersensitive response. These results indicate that there is resistance to RhYMV in the soybean germplasm. The significance of these results is discussed.

  14. Biosynthesis of gold nanoparticles by the living freshwater diatom Eolimna minima, a species developed in river biofilms.

    Science.gov (United States)

    Feurtet-Mazel, Agnès; Mornet, Stéphane; Charron, Laëtitia; Mesmer-Dudons, Nathalie; Maury-Brachet, Régine; Baudrimont, Magalie

    2016-03-01

    Testing biotransformation capacities of living aquatic microalgae diatoms to naturally synthetize gold nanoparticles (AuNP) from gold salts and assessing aftereffects on their viability by microscope observations is a great challenge. In this work, a laboratory experiment was conducted, which aimed to observe (i) directly by transmission electronic and light microscopy and (ii) through indirect measurements (UV-visible spectroscopy) the periphytic freshwater diatom Eolimna minima exposed to gold salts. This work revealed the capacity of E. minima to intracellularly biosynthetize AuNP and to tolerate it. AuNP synthesis appears as a mechanism of detoxification to protect diatom from gold salt contamination. We also pointed out the risks associated with the spread of diatoms full of AuNP, through the trophic web of freshwater ecosystems. The preponderant part of the diatoms in natural biofilms associated with their position at the basis of the trophic webs in rivers could then make them responsible for the contamination of their consumers (grazer animals) and consequently for the potential release of AuNP through the entire food web.

  15. Image distortion in narrow beam rotation radiography

    International Nuclear Information System (INIS)

    Welander, U.; Wickman, G.

    1978-01-01

    A general mathematical analysis of the image distortion in narrow beam rotation radiography has been performed. Distortion effects are often evident in panoramic images exposed in clinical practice. It is found that in spite of this general experience panoramic images, exposed with the aid of a rotating narrow beam, are reliable for ordinary clinical demands when the object morphology is to be assessed. This statement is valid provided that the object has been properly positioned at the exposure. (Auth.)

  16. Geomagnetic detection of the sectorial solar magnetic field and the historical peculiarity of minimum 23-24

    Science.gov (United States)

    Love, Jeffrey J.; Rigler, J.

    2012-01-01

    [1] Analysis is made of the geomagnetic-activityaaindex covering solar cycle 11 to the beginning of 24, 1868–2011. Autocorrelation shows 27.0-d recurrent geomagnetic activity that is well-known to be prominent during solar-cycle minima; some minima also exhibit a smaller amount of 13.5-d recurrence. Previous work has shown that the recent solar minimum 23–24 exhibited 9.0 and 6.7-d recurrence in geomagnetic and heliospheric data, but those recurrence intervals were not prominently present during the preceding minima 21–22 and 22–23. Using annual-averages and solar-cycle averages of autocorrelations of the historicalaadata, we put these observations into a long-term perspective: none of the 12 minima preceding 23–24 exhibited prominent 9.0 and 6.7-d geomagnetic activity recurrence. We show that the detection of these recurrence intervals can be traced to an unusual combination of sectorial spherical-harmonic structure in the solar magnetic field and anomalously low sunspot number. We speculate that 9.0 and 6.7-d recurrence is related to transient large-scale, low-latitude organization of the solar dynamo, such as seen in some numerical simulations.

  17. SOLAR-ISS: A new reference spectrum based on SOLAR/SOLSPEC observations

    Science.gov (United States)

    Meftah, M.; Damé, L.; Bolsée, D.; Hauchecorne, A.; Pereira, N.; Sluse, D.; Cessateur, G.; Irbah, A.; Bureau, J.; Weber, M.; Bramstedt, K.; Hilbig, T.; Thiéblemont, R.; Marchand, M.; Lefèvre, F.; Sarkissian, A.; Bekki, S.

    2018-03-01

    Context. Since April 5, 2008 and up to February 15, 2017, the SOLar SPECtrometer (SOLSPEC) instrument of the SOLAR payload on board the International Space Station (ISS) has performed accurate measurements of solar spectral irradiance (SSI) from the middle ultraviolet to the infrared (165 to 3088 nm). These measurements are of primary importance for a better understanding of solar physics and the impact of solar variability on climate. In particular, a new reference solar spectrum (SOLAR-ISS) is established in April 2008 during the solar minima of cycles 23-24 thanks to revised engineering corrections, improved calibrations, and advanced procedures to account for thermal and aging corrections of the SOLAR/SOLSPEC instrument. Aims: The main objective of this article is to present a new high-resolution solar spectrum with a mean absolute uncertainty of 1.26% at 1σ from 165 to 3000 nm. This solar spectrum is based on solar observations of the SOLAR/SOLSPEC space-based instrument. Methods: The SOLAR/SOLSPEC instrument consists of three separate double monochromators that use concave holographic gratings to cover the middle ultraviolet (UV), visible (VIS), and infrared (IR) domains. Our best ultraviolet, visible, and infrared spectra are merged into a single absolute solar spectrum covering the 165-3000 nm domain. The resulting solar spectrum has a spectral resolution varying between 0.6 and 9.5 nm in the 165-3000 nm wavelength range. We build a new solar reference spectrum (SOLAR-ISS) by constraining existing high-resolution spectra to SOLAR/SOLSPEC observed spectrum. For that purpose, we account for the difference of resolution between the two spectra using the SOLAR/SOLSPEC instrumental slit functions. Results: Using SOLAR/SOLSPEC data, a new solar spectrum covering the 165-3000 nm wavelength range is built and is representative of the 2008 solar minimum. It has a resolution better than 0.1 nm below 1000 nm and 1 nm in the 1000-3000 nm wavelength range. The new

  18. Differential Expression of Antioxidant Enzymes During Degradation of Azo Dye Reactive black 8 in Hairy roots of Physalis minima L.

    Science.gov (United States)

    Jha, Pamela; Modi, Nikita; Jobby, Renitta; Desai, Neetin

    2015-01-01

    The enzymes involved in the protection of plant metabolism in presence of azo dye was characterized by studying activities of the role of antioxidant enzymes in the hairy roots (HRs) of Physalis minima L. during degradation of an azo dye, Reactive Black 8 (RB8). When the HRs were exposed to RB8 (30 mg L(-1)), a  nine fold increase in SOD activity was observed after 24 h, while 22 and 50 fold increase in activity was observed for POX and APX respectively after 72 h, whereas there was no significant change in activity of CAT. The activation of different antioxidant enzymes at different time intervals under dye stress suggests the synchronized functioning of antioxidant machinery to protect the HRs from oxidative damage. FTIR analysis confirmed the degradation of dye and the non-toxic nature of metabolites formed after dye degradation was confirmed by phytotoxicity study.

  19. Capacity of the aquatic fern (Salvinia minima Baker) to accumulate high concentrations of nickel in its tissues, and its effect on plant physiological processes

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, Ignacio I.; Espadas-Gil, Francisco; Talavera-May, Carlos; Fuentes, Gabriela; Santamaría, Jorge M., E-mail: jorgesm@cicy.mx

    2014-10-15

    Highlights: • We document the capacity of an aquatic fern to hyper-accumulate Ni. • Effects of high Ni concentrations uptake on plant performance is documented. • High concentration of Ni in tissues damage photosynthesis. • Damage is related to carboxylation mechanisms than to electron transfer efficiency. • S. minima is a good candidate for remediation of water bodies contaminated with Ni. - Abstract: An experiment was designed to assess the capacity of Salvinia minima Baker to uptake and accumulate nickel in its tissues and to evaluate whether or not this uptake can affect its physiology. Our results suggest that S. minima plants are able to take up high amounts of nickel in its tissues, particularly in roots. In fact, our results support the idea that S. minima might be considered a hyper-accumulator of nickel, as it is able to accumulate 16.3 mg g{sup −1} (whole plant DW basis). Our results also showed a two-steps uptake pattern of nickel, with a fast uptake of nickel at the first 6 to 12 h of being expose to the metal, followed by a slow take up phase until the end of the experiment at 144 h. S. minima thus, may be considered as a fern useful in the phytoremediation of residual water bodies contaminated with this metal. Also from our results, S. minima can tolerate fair concentrations of the metal; however, at concentrations higher than 80 μM Ni (1.5 mg g{sup −1} internal nickel concentration), its physiological performance can be affected. For instance, the integrity of cell membranes was affected as the metal concentration and exposure time increased. The accumulation of high concentrations of internal nickel did also affect photosynthesis, the efficiency of PSII, and the concentration of photosynthetic pigments, although at a lower extent.

  20. Highly Tunable Narrow Bandpass MEMS Filter

    KAUST Repository

    Hafiz, Md Abdullah Al

    2017-07-07

    We demonstrate a proof-of-concept highly tunable narrow bandpass filter based on electrothermally and electrostatically actuated microelectromechanical-system (MEMS) resonators. The device consists of two mechanically uncoupled clamped-clamped arch resonators, designed such that their resonance frequencies are independently tuned to obtain the desired narrow passband. Through the electrothermal and electrostatic actuation, the stiffness of the structures is highly tunable. We experimentally demonstrate significant percentage tuning (~125%) of the filter center frequency by varying the applied electrothermal voltages to the resonating structures, while maintaining a narrow passband of 550 ± 50 Hz, a stopband rejection of >17 dB, and a passband ripple ≤ 2.5 dB. An analytical model based on the Euler-Bernoulli beam theory is used to confirm the behavior of the filter, and the origin of the high tunability using electrothermal actuation is discussed.

  1. A naturally narrow positive-parity Θ+

    International Nuclear Information System (INIS)

    Carlson, Carl E.; Carone, Christopher D.; Kwee, Herry J.; Nazaryan, Vahagn

    2004-01-01

    We present a consistent color-flavor-spin-orbital wave function for a positive-parity Θ + that naturally explains the observed narrowness of the state. The wave function is totally symmetric in its flavor-spin part and totally antisymmetric in its color-orbital part. If flavor-spin interactions dominate, this wave function renders the positive-parity Θ + lighter than its negative-parity counterpart. We consider decays of the Θ + and compute the overlap of this state with the kinematically allowed final states. Our results are numerically small. We note that dynamical correlations between quarks are not necessary to obtain narrow pentaquark widths

  2. Narrow-Bicliques: Cryptanalysis of Full IDEA

    DEFF Research Database (Denmark)

    Khovratovich, D.; Leurent, G.; Rechberger, C.

    2012-01-01

    improves time and data complexities over existing attacks. We consider the first 7.5 rounds of IDEA and demonstrate a variant of the approach that works with practical data complexity. The conceptual contribution is the narrow-bicliques technique: the recently introduced independent-biclique approach...... extended with ways to allow for a significantly reduced data complexity with everything else being equal. For this we use available degrees of freedom as known from hash cryptanalysis to narrow the relevant differential trails. Our cryptanalysis is of high computational complexity, and does not threaten...

  3. The narrow U(3. 1) state

    Energy Technology Data Exchange (ETDEWEB)

    Ono, S.; Furui, S.; Mitra, A.N.

    1988-09-01

    The auhtors show that the decay of a certain kind of the diquonium is severely restricted for various reasons. They conclude that the narrow U(3.1) is a good candidate for the diquonium (sq)/sub 6/ (q-barq-bar)/sub 6/sup -//.

  4. Undersea Laser Communication with Narrow Beams

    Science.gov (United States)

    2015-09-29

    Underwater Wireless Optical Communications ...Gbit/s underwater wireless optical communications using directly modulated 520 nm laser diode," Optics Express, vol. 23, no. 16, pp. 20743-20748, 2015. ... wireless communication with narrow optical beams. The undersea systems analysis herein is inspired by lessons learned in the last few

  5. Narrow linewidth pulsed optical parametric oscillator

    Indian Academy of Sciences (India)

    Abstract. Tunable narrow linewidth radiation by optical parametric oscillation has many applications, particularly in spectroscopic investigation. In this paper, different techniques such as injection seeding, use of spectral selecting element like grating, grat- ing and etalon in combination, grazing angle of incidence, entangled ...

  6. Narrow-headed garter snake (Thamnophis rufipunctatus)

    Science.gov (United States)

    Nowak, Erika M.

    2006-01-01

    The narrow-headed garter snake is a harmless, nonvenomous snake that is distinguished by its elongated, triangular-shaped head and the red or dark spots on its olive to tan body. Today, the narrow-headed garter snake is a species of special concern in the United States because of its decline over much of its historic range. Arizona's Oak Creek has historically contained the largest population of narrow-headed garter snakes in the United States. The U.S. Geological Survey (USGS) and the Arizona Game and Fish Department jointly funded research by USGS scientists in Oak Creek to shed light on the factors causing declining population numbers. The research resulted in better understanding of the snake's habitat needs, winter and summer range, and dietary habits. Based on the research findings, the U.S. Forest Service has developed recommendations that visitors and local residents can adopt to help slow the decline of the narrow-headed garter snake in Oak Creek.

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. Calculating all local minima on liquidus surfaces using the FactSage software and databases and the Mesh Adaptive Direct Search algorithm

    International Nuclear Information System (INIS)

    Gheribi, Aimen E.; Robelin, Christian; Digabel, Sebastien Le; Audet, Charles; Pelton, Arthur D.

    2011-01-01

    Highlights: → Systematic search of low melting temperatures in multicomponent systems. → Calculation of eutectic in multicomponent systems. → The FactSage software and the direct search algorithm are used simultaneously. - Abstract: It is often of interest, for a multicomponent system, to identify the low melting compositions at which local minima of the liquidus surface occur. The experimental determination of these minima can be very time-consuming. An alternative is to employ the CALPHAD approach using evaluated thermodynamic databases containing optimized model parameters giving the thermodynamic properties of all phases as functions of composition and temperature. Liquidus temperatures are then calculated by Gibbs free energy minimization algorithms which access the databases. Several such large databases for many multicomponent systems have been developed over the last 40 years, and calculated liquidus temperatures are generally quite accurate. In principle, one could then search for local liquidus minima by simply calculating liquidus temperatures over a compositional grid. In practice, such an approach is prohibitively time-consuming for all but the simplest systems since the required number of grid points is extremely large. In the present article, the FactSage database computing system is coupled with the powerful Mesh Adaptive Direct Search (MADS) algorithm in order to search for and calculate automatically all liquidus minima in a multicomponent system. Sample calculations for a 4-component oxide system, a 7-component chloride system, and a 9-component ferrous alloy system are presented. It is shown that the algorithm is robust and rapid.

  12. The Dynamo Dialectic: An Inside Look at the Current Solar Minimum

    Science.gov (United States)

    Miesch, M. S.

    2010-06-01

    Although the causal chain is by no means straightforward, variations among solar minima observed in the solar atmosphere and heliosphere must ultimately arise from the capricious nature of the dynamo operating in the solar interior. Given the highly turbulent conditions in the solar envelope, chaotic temporal variation should be expected. A deep understanding of long-term solar variability must come from a conceptual synthesis between the inherent disorder of a turbulent dynamo as manifested by the magnetic carpet and the patent order exhibited by the solar activity cycle. This is the dynamo dialectic, thesis-antithesis-synthesis; the solar dynamo is cyclic, the solar dynamo is chaotic, the solar dynamo is both. I will review our current understanding of how order and chaos coexist in the Sun based on simplified but illustrative systems including both mean-field dynamo models and 3D MHD convection simulations.

  13. Paravannella minima n. g. n. sp. (Discosea, Vannellidae) and distinction of the genera in the vannellid amoebae.

    Science.gov (United States)

    Kudryavtsev, Alexander

    2014-06-01

    Paravannella minima n. g. n. sp. (Amoebozoa, Vannellidae) isolated from a freshwater aquarium, possesses all light-microscopic and ultrastructural characteristics of the genus Vannella, being one of the smallest species among the vannellid amoebae (cell size during locomotion usually between 4.5 and 10μm). At the same time, sequence analysis of the genes encoding for nuclear SSU rRNA, actin and mitochondrial Cox1 shows this species as the earliest-branching vannellid that appears to be sister to the rest of this clade. This is correlated with the presence of some plesiomorphic characters; in particular, the secondary structure of the hypervariable helices E23-1-E23-7 in the studied species is shared with Vannella and most of the genera of Dactylopodida. The cell coat structure of the studied species corresponds to the hypothesis that vannellid amoebae were ancestrally enclosed in a cell coat consisting of pentagonal glycostyles that have undergone multiple independent losses in various clades of Vannellidae. Copyright © 2013 Elsevier GmbH. All rights reserved.

  14. Signatures of the Primordial Universe from Its Emptiness: Measurement of Baryon Acoustic Oscillations from Minima of the Density Field.

    Science.gov (United States)

    Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Liang, Yu; Zhao, Cheng; Tao, Charling; Rodríguez-Torres, Sergio; Eisenstein, Daniel J; Gil-Marín, Héctor; Kneib, Jean-Paul; McBride, Cameron; Percival, Will J; Ross, Ashley J; Sánchez, Ariel G; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Zhao, Gong-Bo

    2016-04-29

    Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but it is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumsphere centers constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of luminous red galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3σ BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centers represent the most quiet places in the Universe, keeping in mind the cosmos origin and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.

  15. Data Analysis of Minima Total Cross-sections of Nitrogen-14 on JENDL-3.2Nuclear Data File

    International Nuclear Information System (INIS)

    Suwoto; Pandiangan, Tumpal; Ferhat-Aziz

    2000-01-01

    The integral tests of neutron cross-section for shielding material suchas nitrogen-14 contained in JENDL-3.2 file have been performed. Analysis ofthe calculation for nitrogen-14 was based on the MAEKER's ORNL-BroomstickExperiment at ORNL-USA. For the data comparison, the calculation analysiswith JENDL-3.1 file, ENDF/B-IV file, ENDF/B-VI file and JEF2.2 have also beencarried out. The overall calculation results by using JENDL-3.2 evaluationshowed good agreement with the experimental data, as well as those with theENDF/B-VI evaluation. In particular, the JENDL-3.2 evaluation gave betterresults than JENDL-3.1 evaluation and ENDF/B-IV. It was been concluded thatthe total cross-sections of Nitrogen-14 contained in JENDL-3.2 file is invery good agreement with the experimental results, although the totalcross-section in the energy range between 0.5 MeV and 0.9 MeV on fileJENDL-3.2 was small (about 4% lower), and minima of total cross-sections wasdeeper. (author)

  16. Analytical approximations for wide and narrow resonances

    International Nuclear Information System (INIS)

    Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

    2005-01-01

    This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U 238 were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)

  17. Analytical approximations for wide and narrow resonances

    Energy Technology Data Exchange (ETDEWEB)

    Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: aquilino@lmp.ufrj.br

    2005-07-01

    This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U{sup 238} were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)

  18. Interfacially driven transport in narrow channels

    OpenAIRE

    Bacchin, Patrice

    2018-01-01

    When colloids flow in a narrow channel, the transport efficiency is controlled by the non-equilibrium interplay between colloid-wall interactions and hydrodynamics. In this paper, a general, unifying description of colloidal dispersion flow in a confined system is proposed. A momentum and mass balance founded framework implementing the colloid-interface interactions is introduced. The framework allows us to depict how interfacial forces drive the particles and the liquid flows. The interfacia...

  19. Experimental evidence of narrow non strange dibaryons

    International Nuclear Information System (INIS)

    Willis, N.; Tatischeff, B.; Comets, M.P.; Le Bornec, Y.; Bonin, B.; Lugol, J.C.; Mayer, B.; Terrien, Y.; Beurtey, R.; Boudard, A.; Durand, J.M.; Fassnacht, P.; Hibou, F.

    1987-01-01

    The authors discuss the structures observed with masses above the pion production threshold (M > 2.015 GeV). An extensive study of p( 3 He,d)X and 3 He(p,d)X reactions at different angles and energies has been performed at Saturne. Narrow structures were observed at the same mass position in missing mass spectra. 16 refs.; 3 figs

  20. Electron correlations in narrow band systems

    International Nuclear Information System (INIS)

    Kishore, R.

    1983-01-01

    The effect of the electron correlations in narrow bands, such as d(f) bands in the transition (rare earth) metals and their compounds and the impurity bands in doped semiconductors is studied. The narrow band systems is described, by the Hubbard Hamiltonian. By proposing a local self-energy for the interacting electron, it is found that the results are exact in both atomic and band limits and reduce to the Hartree Fock results for U/Δ → 0, where U is the intra-atomic Coulomb interaction and Δ is the bandwidth of the noninteracting electrons. For the Lorentzian form of the density of states of the noninteracting electrons, this approximation turns out to be equivalent to the third Hubbard approximation. A simple argument, based on the mean free path obtained from the imaginary part of the self energy, shows how the electron correlations can give rise to a discontinous metal-nonmetal transition as proposed by Mott. The band narrowing and the existence of the satellite below the Fermi energy in Ni, found in photoemission experiments, can also be understood. (Author) [pt

  1. Optimal geometries and harmonic vibrational frequencies of the global minima of water clusters (H2O)n, n = 2–6, and several hexamer local minima at the CCSD(T) level of theory

    Energy Technology Data Exchange (ETDEWEB)

    Miliordos, Evangelos; Aprà, Edoardo; Xantheas, Sotiris S.

    2013-01-01

    We report the first optimum geometries and harmonic vibrational frequencies for the ring pentamer and several water hexamer (prism, cage, cyclic and two book) at the CCSD(T)/aug-cc-pVDZ level of theory. All five hexamer isomer minima previously reported by MP2 are also minima on the CCSD(T) potential energy surface (PES). In addition, all CCSD(T) minimum energy structures for the n=2-6 cluster isomers are quite close to the ones previously obtained by MP2 on the respective PESs, as confirmed by a modified Procrustes analysis that quantifies the difference between any two cluster geometries. The CCSD(T) results confirm the cooperative effect of the homodromic ring networks (systematic contraction of the nearest-neighbor (nn) intermolecular separations with cluster size) previously reported by MP2, albeit with O-O distances shorter by ~0.02 Å, indicating that MP2 overcorrects this effect. The harmonic frequencies at the minimum geometries were obtained by the double differentiation of the CCSD(T) energy using an efficient scheme based on internal coordinates that reduces the number of required single point energy evaluations by ~15% when compared to the corresponding double differentiation using Cartesian coordinates. Negligible differences between MP2 and CCSD(T) are found for the librational modes, while uniform increases of ~15 and ~25 cm-1 are observed for the bending and “free” OH harmonic frequencies. The largest differences between MP2 and CCSD(T) are observed for the harmonic hydrogen bonded frequencies. The CCSD(T) red shifts from the monomer frequencies (Δω) are smaller than the MP2 ones, due to the fact that the former produces shorter elongations (ΔR) of the respective hydrogen bonded OH lengths from the monomer value with respect to the latter. Both the MP2 and CCSD(T) results for the hydrogen bonded frequencies were found to closely follow the relation - Δω = s · ΔR, with a rate of s = 20.3 cm-1 / 0.001 Å. The CCSD

  2. Minima Epigraphica Cluniensia

    Directory of Open Access Journals (Sweden)

    Joaquín Luis Gómez-Pantoja Fernández-Salguero

    2016-04-01

    Full Text Available Se describen a continuación siete inscripciones procedentes del Clunia Sulpicia (Coruña del Conde/Peñalba de Castro, Burgos; de ellas, cinco son inéditas y las otras dos se conocian pero sin edición completa. Cuatro de los letreros corresponden a grafitos sobre estuco, dos escritos en griego; ambas circuntancias son novedosas en este sitio arqueológico.This paper deals with some epigraphs found in Clunia Sulpicia (Coruña del Conde/Peñalba de Castro, Burgos province, Spain. Five of them are new findings and the other two lacked a complete edition. It’s worth noticing that four texts are graffiti, two written in Greek script.

  3. Pool Boiling CHF in Inclined Narrow Annuli

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    2010-01-01

    Pool boiling heat transfer has been studied extensively since it is frequently encountered in various heat transfer equipment. Recently, it has been widely investigated in nuclear power plants for application to the advanced light water reactors designs. Through the review on the published results it can be concluded that knowledge on the combined effects of the surface orientation and a confined space on pool boiling heat transfer is of great practical importance and also of great academic interest. Fujita et al. investigated pool boiling heat transfer, from boiling inception to the critical heat flux (CHF, q' CHF ), in a confined narrow space between heated and unheated parallel rectangular plates. They identified that both the confined space and the surface orientation changed heat transfer much. Kim and Suh changed the surface orientation angles of a downward heating rectangular channel having a narrow gap from the downward-facing position (180 .deg.) to the vertical position (90 .deg.). They observed that the CHF generally decreased as the inclination angle (θ ) increased. Yao and Chang studied pool boiling heat transfer in a confined heat transfer for vertical narrow annuli with closed bottoms. They observed that when the gap size ( s ) of the annulus was decreased the effect of space confinement to boiling heat transfer increased. The CHF was occurred at much lower value for the confined space comparing to the unconfined pool boiling. Pool boiling heat transfer in narrow horizontal annular crevices was studied by Hung and Yao. They concluded that the CHF decreased with decreasing gap size of the annuli and described the importance of the thin film evaporation to explain the lower CHF of narrow crevices. The effect of the inclination angle on the CHF on countercurrent boiling in an inclined uniformly heated tube with closed bottoms was also studied by Liu et al. They concluded that the CHF reduced with the inclination angle decrease. A study was carried out

  4. 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...

  5. 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

  6. Cervical spinal canal narrowing in idiopathic syringomyelia

    Energy Technology Data Exchange (ETDEWEB)

    Struck, Aaron F. [Massachusetts General Hospital, Department of Neurology, Boston, MA (United States); Carr, Carrie M. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Shah, Vinil [University of California San Francisco, Department of Radiology, San Francisco, CA (United States); Hesselink, John R. [University of California San Diego, Department of Radiology, San Diego, CA (United States); Haughton, Victor M. [University of Wisconsin, Department of Radiology, Madison, WI (United States)

    2016-08-15

    The cervical spine in Chiari I patient with syringomyelia has significantly different anteroposterior diameters than it does in Chiari I patients without syringomyelia. We tested the hypothesis that patients with idiopathic syringomyelia (IS) also have abnormal cervical spinal canal diameters. The finding in both groups may relate to the pathogenesis of syringomyelia. Local institutional review boards approved this retrospective study. Patients with IS were compared to age-matched controls with normal sagittal spine MR. All subjects had T1-weighted spin-echo (500/20) and T2-weighted fast spin-echo (2000/90) sagittal cervical spine images at 1.5 T. Readers blinded to demographic data and study hypothesis measured anteroposterior diameters at each cervical level. The spinal canal diameters were compared with a Mann-Whitney U test. The overall difference was assessed with a Friedman test. Seventeen subjects were read by two reviewers to assess inter-rater reliability. Fifty IS patients with 50 age-matched controls were studied. IS subjects had one or more syrinxes varying from 1 to 19 spinal segments. Spinal canal diameters narrowed from C1 to C3 and then enlarged from C5 to C7 in both groups. Diameters from C2 to C4 were narrower in the IS group (p < 0.005) than in controls. The ratio of the C3 to the C7 diameters was also smaller (p = 0.004) in IS than controls. Collectively, the spinal canal diameters in the IS were significantly different from controls (Friedman test p < 0.0001). Patients with IS have abnormally narrow upper and mid cervical spinal canal diameters and greater positive tapering between C3 and C7. (orig.)

  7. Narrow Linewidth Laser Cooling via Adiabatic Transfer

    Science.gov (United States)

    Bartolotta, John; Holland, Murray; Norcia, Matthew; Thompson, James; Cline, Julia

    2017-04-01

    We simulate and provide a theoretical framework for a new cooling method applicable to particles with narrow-linewidth optical transitions. The particles are adiabatically transferred to lower momentum states upon interaction with counter-propagating laser beams that are repeatedly swept over the transition frequency. A reduced reliance on spontaneous emission (compared to Doppler cooling) allows for larger slowing forces. Cooling via a 7.6 kHz dipole forbidden transition in Strontium-88 is simulated using one-dimensional quantum jump and c-number Langevin equation methods. This ``sweep cooling'' mechanism also shows promise for application to systems lacking closed cycling transitions, such as molecules.

  8. Critical unpairing currents in narrow niobium films

    International Nuclear Information System (INIS)

    Gershenzon, M.E.; Gubankov, V.N.

    1979-01-01

    Investigated are the dependences of critical currents of narrow ( with the width of W=0.5-15 μm) superconducting niobium films on temperature and a magnetic field. The proposed method of film production with the width of the 1μm order and with small edge inhomogeneities ((<=500 A) permitted to realize the Ginsburg-Landau unpairing currents in the wide range of temperatures. The correct comparison with the theory showed that the unpairing currents are observed if W(< or approximately) 2delta, where delta is the effective depth of the penetration of the perpendicular magnetic field

  9. Itinerant ferromagnetism in the narrow band limit

    CERN Document Server

    Liu, S H

    2000-01-01

    It is shown that in the narrow band, strong interaction limit the paramagnetic state of an itinerant ferromagnet is described by the disordered local moment state. As a result, the Curie temperature is orders of magnitude lower than what is expected from the large exchange splitting of the spin bands. An approximate analysis has also been carried out for the partially ordered state, and the result explains the temperature evolvement of the magnetic contributions to the resistivity and low-energy optical conductivity of CrO sub 2.

  10. Volume dips; spot price ranges narrow

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    This article is the September 1994 uranium market summary. Volume in the spot concentrates market fell below 1 million lbs U3O8. In total, twelve deals took place compared to 28 deals in August. Of the twelve deals, three took place in the spot concentrates market, two took place in the medium and long-term market, three in the conversion market, and four in the enrichment market. Restricted prices weakened, but unrestricted prices firmed slightly. The enrichment price range narrowed a bit

  11. DISCOSIPHONELLA MINIMA SENOWBARI-DARYAN & LINK AND SOLENOLMIA? PARVA N. SP. ("SPHINCTOZOA", PORIFERA FROM THE UPPER TRIASSIC (NORIAN OF THE SOUTHERN APPENNINES (NORTHERN CALABRIA/ITALY

    Directory of Open Access Journals (Sweden)

    BABA SENOWBARI-DARYAN

    2009-07-01

    Full Text Available Two hypercalcified sphinctozoan sponges are described from several localities of dolomitic Norian reefs of northern Calabria (southern Italy. Solenolmia? parva n. sp. occurs as an extremely abundant, albeit local, component in peculiar bioconstructions dominated by serpulids and microbialitic crusts. Discosiphonella minima Senowbari-Daryan & Link, previously recognized only in the type locality of Turkey, has been now found also as a minor component in association with other typical "Dachstein" reef biota, such as corals, sponges, microbial crusts and fragments of "microproblematica". Solenolmia? parva assemblage represents the primary framebuilder of small build-ups which developed on the margins of restricted intraplatform basins. The Discosiphonella minima assemblages were found as resedimented blocks along the slope of intraplatform anoxic basins. The distribution of the different reefal assemblages of Northern Calabria can be related to the paleogeographic position of northern Calabria with respect to the evolution of Triassic crustal extension in western Mediterranean. 

  12. Pinpointing Gap Minima in Ba(Fe0:94Co0:06)2 via Band Structure Calculations and Electronic Raman Scattering

    Science.gov (United States)

    2010-08-03

    structure for the Fe-pnictide superconductors is still rather rudimentary, with several conflicting reports of either nodes, deep gap minima, or fully...2. PACS numbers: 74.25.nd,74.70.Xa,74.20.Pq,71.15.Mb Since the discovery of high temperature superconductivity in the iron pnictides, identifying the...a substantial interband contribution deriving largely from these same bands. These results support the conjecture based on symmetry in Ref. 6 that

  13. Cluster headache or narrow angle glaucoma?

    Directory of Open Access Journals (Sweden)

    Prasad Palimar

    1991-01-01

    Full Text Available A 47 year old man with episodes of attacks of pain, redness and mild blurring of vision was investigated for narrow angle glaucoma in view of shallow anterior chambers and a cupped optic disc. The history was reviewed following a spontaneous attack in hospital, which had features other than acute glaucoma. A diagnosis of cluster headache was made on the basis of tests. Cluster headache has been defined as unilateral intense pain, involving the eye and head on one side, usually associated with flushing, nasal congestion and lacrimation; the attacks recurring one or more times daily and lasting 20 - 120 minutes. Such attacks commonly continue for weeks or months and are separated by an asymptomatic period of months to years. This episodic nature, together with unilaterality and tendency to occur at night, closely mimics narrow angle glaucoma. Further, if patients have shallow anterior chambers and disc cupping, the differentiation becomes more difficult yet critical. Resource to provocative tests is often the only answer as the following case report demonstrates.

  14. Narrow field electromagnetic sensor system and method

    International Nuclear Information System (INIS)

    McEwan, T.E.

    1996-01-01

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs

  15. Narrow field electromagnetic sensor system and method

    Science.gov (United States)

    McEwan, Thomas E.

    1996-01-01

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

  16. Samba Solar; Samba Solar

    Energy Technology Data Exchange (ETDEWEB)

    Thurston, Charles W.

    2012-07-01

    Brazil, the biggest country of the South American subcontinent, has discovered the power of solar energy. Brazil recently introduced net metering of solar power plants and started to open the power supply grid to PV systems. The market has great potential as Brazil is the world's sixth biggest national economy.

  17. Active Brownian motion in a narrow channel

    Science.gov (United States)

    Ao, X.; Ghosh, P. K.; Li, Y.; Schmid, G.; Hänggi, P.; Marchesoni, F.

    2014-12-01

    We review recent advances in rectification control of artificial microswimmers, also known as Janus particles, diffusing along narrow, periodically corrugated channels. The swimmer self-propulsion mechanism is modeled so as to incorporate a nonzero torque (propulsion chirality). We first summarize the effects of chirality on the autonomous current of microswimmers freely diffusing in channels of different geometries. In particular, left-right and upside-down asymmetric channels are shown to exhibit different transport properties. We then report new results on the dependence of the diffusivity of chiral microswimmers on the channel geometry and their own self-propulsion mechanism. The self-propulsion torque turns out to play a key role as a transport control parameter.

  18. Search for narrow four-baryon states

    International Nuclear Information System (INIS)

    Badelek, B.

    1981-01-01

    Highly excited (4.10 2 ) four-baryon resonances have been searched for in the missing-mass spectrum of the reaction π - + 4 He → π - + X at 5 GeV/c in the region of small four-momentum transfer (0.005 2 ), where one of the decay products of the X is either proton or deuteron or triton. No resonance signal is seen in the mass spectrum of X. Within our limited acceptance, the cross section for the production of a narrow (GAMMA approx. 20 MeV/c 2 ) four-baryon state with mass 4.9 GeV/c 2 is estimated to be smaller than approx. 100 nb. (orig.)

  19. Analysis of narrow effects in pp annihilations

    CERN Document Server

    Defoix, C

    1972-01-01

    The author describes briefly some methods of analysis that final states involving a number of like particles require. A first method consists of separating two competing channels to minimize the reflections due to the undesirable one. Later techniques of analysis lead to the isolation of the only channel of interest and circumvention of the problems of background and reflections due to irrelevant final states. Generally, all these processes are based on the presence of a narrow and identified resonance, for example the eta /sup 0/ or omega /sup 0/ ( to pi /sup +/ pi /sup -/ pi /sup 0/). To be efficient, it is necessary that the observed width of such a basic resonance not be increased too much by experimental errors. (6 refs).

  20. 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...

  1. Solar Cookers.

    Science.gov (United States)

    King, Richard C.

    1981-01-01

    Describes the use of solar cookers in the science classroom. Includes instructions for construction of a solar cooker, an explanation of how solar cookers work, and a number of suggested activities. (DS)

  2. Narrow-band UVB (TL-01) phototherapy: an effective preventative treatment for the photodermatoses

    Energy Technology Data Exchange (ETDEWEB)

    Collins, P.; Ferguson, J. [Ninewells Hospital and Medical School, Dundee (United Kingdom)

    1995-06-01

    Twenty patients with photodermatoses [actinic prurigo (n = 6), hydroa vacciniforme (n = 4), idiopathic solar urticaria (n 1), amiodarone-induced photosensitivity (n = 1) and a range of cutaneous porphyrias (n = 8)] were treated with a ``hardening`` course of narrow-band ultraviolet B (TL-01) phototherapy in springtime. The response to phototherapy was monitored subjectively, by interviewing patients after the summer, and objectively by monochromator phototesting, before and after phototherapy. Fifteen patients reported that treatment was worthwhile. Monochromator phototesting after phototherapy revealed a fourfold increase in the minimal erythema dose in those with abnormal photosensitivity to ultraviolet A wavebands. Adverse effects included erythema (seven patients), pruritus (five) and provocation of the eruption (four). We now routinely consider narrow-band UVB phototherapy for problem photodermatoses. (author).

  3. Thermodynamic methodology for the design of solar dryers operated with flat solar collectors; Metodologia termodinamica para el diseno de secadores operados con calentadores solares planos

    Energy Technology Data Exchange (ETDEWEB)

    Torres Reyes, Ernestina; Navarrete Gonzalez, Jose L; Ibarra Salazar, Beatriz A; Picon Nunez, Martin [Instituto de Investigaciones Cientificas, Universidad de Guanajuato, Guanjuato, Guanajuato (Mexico)

    2000-07-01

    In this paper a thermal performance analysis of solar drying process at operating varying conditions is presented. It is described semi-empirical models to thermal characterization of an experimental device. A simulator of thermal performance for operating varying conditions was developed as a part of the procedure of thermal design of solar dryers. On the other hand, it is described a simplified method to design solar collectors based on the determination of minimum entropy generation during the thermal conversion of the solar device by using the thermal analysis procedure established and the method derived of the second law of the Thermodynamics are finally presented. [Spanish] En este trabajo se presenta el analisis termico del comportamiento del sistema -colector solar camara de secado-. Se describen los modelos semi-empiricos con los que se caracterizo termicamente un secador solar experimental del tipo indirecto. Se presenta tambien un procedimiento de diseno de equipo de secado que toma en cuenta las condiciones variables de operacion que presentan los dispositivos solares. Por otro lado se describe un procedimiento simplificado de diseno, basado en un analisis derivado de la segunda ley de la Termodinamica. Esta metodologia se fundamenta en la minima generacion de entropia durante la conversion termica de la energia solar, utilizando colectores solares planos. Finalmente se presentan los resultados del diseno preliminar de equipo de secado utilizando los dos procedimientos mencionados.

  4. High-latitude Conic Current Sheets in the Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Khabarova, Olga V.; Obridko, Vladimir N.; Kharshiladze, Alexander F. [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Sciences (IZMIRAN), Moscow (Russian Federation); Malova, Helmi V. [Scobeltsyn Nuclear Physics Institute of Lomonosov Moscow State University, Moscow (Russian Federation); Kislov, Roman A.; Zelenyi, Lev M. [Space Research Centre of the Polish Academy of Sciences (CBK PAN), Warsaw (Poland); Tokumaru, Munetoshi; Fujiki, Ken’ichi [Institute for Space-Earth Environmental Research, Nagoya University (Japan); Sokół, Justyna M.; Grzedzielski, Stan [Space Research Centre of the Polish Academy of Sciences (CBK), Warsaw (Poland)

    2017-02-10

    We provide observational evidence for the existence of large-scale cylindrical (or conic-like) current sheets (CCSs) at high heliolatitudes. Long-lived CCSs were detected by Ulysses during its passages over the South Solar Pole in 1994 and 2007. The characteristic scale of these tornado-like structures is several times less than a typical width of coronal holes within which the CCSs are observed. CCS crossings are characterized by a dramatic decrease in the solar wind speed and plasma beta typical for predicted profiles of CCSs. Ulysses crossed the same CCS at different heliolatitudes at 2–3 au several times in 1994, as the CCS was declined from the rotation axis and corotated with the Sun. In 2007, a CCS was detected directly over the South Pole, and its structure was strongly highlighted by the interaction with comet McNaught. Restorations of solar coronal magnetic field lines reveal the occurrence of conic-like magnetic separators over the solar poles in both 1994 and 2007. Such separators exist only during solar minima. Interplanetary scintillation data analysis confirms the presence of long-lived low-speed regions surrounded by the typical polar high-speed solar wind in solar minima. Energetic particle flux enhancements up to several MeV/ nuc are observed at edges of the CCSs. We built simple MHD models of a CCS to illustrate its key features. The CCSs may be formed as a result of nonaxiality of the solar rotation axis and magnetic axis, as predicted by the Fisk–Parker hybrid heliospheric magnetic field model in the modification of Burger and coworkers.

  5. Foam relaxation in fractures and narrow channels

    Science.gov (United States)

    Lai, Ching-Yao; Rallabandi, Bhargav; Perazzo, Antonio; Stone, Howard A.

    2017-11-01

    Various applications, from foam manufacturing to hydraulic fracturing with foams, involve pressure-driven flow of foams in narrow channels. We report a combined experimental and theoretical study of this problem accounting for the compressible nature of the foam. In particular, in our experiments the foam is initially compressed in one channel and then upon flow into a second channel the compressed foam relaxes as it moves. A plug flow is observed in the tube and the pressure at the entrance of the tube is higher than the exit. We measure the volume collected at the exit of the tube, V, as a function of injection flow rate, tube length and diameter. Two scaling behaviors for V as a function of time are observed depending on whether foam compression is important or not. Our work may relate to foam fracturing, which saves water usage in hydraulic fracturing, more efficient enhanced oil recovery via foam injection, and various materials manufacturing processes involving pressure-driven flow foams.

  6. Thermal tuning On narrow linewidth fiber laser

    Science.gov (United States)

    Han, Peiqi; Liu, Tianshan; Gao, Xincun; Ren, Shiwei

    2010-10-01

    At present, people have been dedicated to high-speed and large-capacity optical fiber communication system. Studies have been shown that optical wavelength division multiplexing (WDM) technology is an effective means of communication to increase the channel capacity. Tunable lasers have very important applications in high-speed, largecapacity optical communications, and distributed sensing, it can provide narrow linewidth and tunable laser for highspeed optical communication. As the erbium-doped fiber amplifier has a large gain bandwidth, the erbium-doped fiber laser can be achieved lasing wavelength tunable by adding a tunable filter components, so tunable filter device is the key components in tunable fiber laser.At present, fiber laser wavelength is tuned by PZT, if thermal wavelength tuning is combined with PZT, a broader range of wavelength tuning is appearance . Erbium-doped fiber laser is used in the experiments,the main research is the physical characteristics of fiber grating temperature-dependent relationship and the fiber grating laser wavelength effects. It is found that the fiber laser wavelength changes continuously with temperature, tracking several temperature points observed the self-heterodyne spectrum and found that the changes in spectra of the 3dB bandwidth of less than 1kHz, and therefore the fiber laser with election-mode fiber Bragg grating shows excellent spectral properties and wavelength stability.

  7. Thermoelectricity in correlated narrow-gap semiconductors

    Science.gov (United States)

    Tomczak, Jan M.

    2018-05-01

    We review many-body effects, their microscopic origin, as well as their impact on thermoelectricity in correlated narrow-gap semiconductors. Members of this class—such as FeSi and FeSb2—display an unusual temperature dependence in various observables: insulating with large thermopowers at low temperatures, they turn bad metals at temperatures much smaller than the size of their gaps. This insulator-to-metal crossover is accompanied by spectral weight-transfers over large energies in the optical conductivity and by a gradual transition from activated to Curie–Weiss-like behaviour in the magnetic susceptibility. We show a retrospective of the understanding of these phenomena, discuss the relation to heavy-fermion Kondo insulators—such as Ce3Bi4Pt3 for which we present new results—and propose a general classification of paramagnetic insulators. From the latter, FeSi emerges as an orbital-selective Kondo insulator. Focussing on intermetallics such as silicides, antimonides, skutterudites, and Heusler compounds we showcase successes and challenges for the realistic simulation of transport properties in the presence of electronic correlations. Further, we explore new avenues in which electronic correlations may contribute to the improvement of thermoelectric performance.

  8. Narrow bandpass cryogenic filter for microwave measurements.

    Science.gov (United States)

    Ivanov, B I; Klimenko, D N; Sultanov, A N; Il'ichev, E; Meyer, H-G

    2013-05-01

    An ultra-wide stopband hairpin bandpass filter with integrated nonuniform transmission lines was designed and fabricated for highly sensitive measurements at cryogenic temperatures down to millikelvin and a frequency range of 10 Hz-10 GHz. The scattering matrices of the filter were characterized at T = 4.2 K. The filter provides a stopband from 10 Hz to 2.2 GHz and from 2.3 GHz to 10 GHz with more than 50 dB and 40 dB of amplitude suppression, respectively. The center frequency of the passband is f0 = 2.25 GHz with a bandwidth Δf = 80 MHz. The maximum insertion loss in the passband is 4 dB. The filter has a 50 Ω input and output impedance, SubMiniature version A connector termination, and significantly reduced form factor. The wide stopband frequency range and narrow passband in conjunction with small dimensions make the filter suitable to use it as a part of a high sensitive readout for superconducting quantum circuits, such as superconducting quantum bits and cryogenic parametric amplifiers.

  9. Nonlinear optical response in narrow graphene nanoribbons

    Science.gov (United States)

    Karimi, Farhad; Knezevic, Irena

    We present an iterative method to calculate the nonlinear optical response of armchair graphene nanoribbons (aGNRs) and zigzag graphene nanoribbons (zGNRs) while including the effects of dissipation. In contrast to methods that calculate the nonlinear response in the ballistic (dissipation-free) regime, here we obtain the nonlinear response of an electronic system to an external electromagnetic field while interacting with a dissipative environment (to second order). We use a self-consistent-field approach within a Markovian master-equation formalism (SCF-MMEF) coupled with full-wave electromagnetic equations, and we solve the master equation iteratively to obtain the higher-order response functions. We employ the SCF-MMEF to calculate the nonlinear conductance and susceptibility, as well as to calculate the dependence of the plasmon dispersion and plasmon propagation length on the intensity of the electromagnetic field in GNRs. The electron scattering mechanisms included in this work are scattering with intrinsic phonons, ionized impurities, surface optical phonons, and line-edge roughness. Unlike in wide GNRs, where ionized-impurity scattering dominates dissipation, in ultra-narrow nanoribbons on polar substrates optical-phonon scattering and ionized-impurity scattering are equally prominent. Support by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0008712.

  10. Carrier Dynamics in Narrow Gap Ferromagnetic Semiconductors

    Science.gov (United States)

    Saha, D.; Pan, X.; Sanders, G. D.; Stanton, C. J.; Bhowmick, M.; Merritt, T.; Khodaparast, G. A.; Feeser, C.; Wessels, B. W.; McGill, S.

    2012-02-01

    Narrow gap ferromagnetic semiconductors are promising materials for spin photonic and spin transport devices because of their small effective masses, small energy gap, and high carrier mobility. We use time resolved differential transmission (TRDT) experiments to study carrier dynamics in ferromagnetic InMnAs and InMnSb. Electronic structure for InMnAs and InMnSb is calculated using an 8-band Pidgeon-Brown model generalized to include the effects of an external magnetic field. Our model includes the effects of the ferromagnetic Mn ions and their coupling to electrons and holes with or without an external magnetic field. Optical transitions are calculated from Fermi's Golden rule and interband transitions at a given pump or probe laser energy are identified. This allows us to understand a sign change seen in the TRDT. Our results show that 1) Phase-Space Filling, 2) Band Gap Renormalization and 3) Free Carrier Absorption all contribute to the TRDT and that the relative importance of these effects depends on the laser probe energy.

  11. COMPARING CORONAL AND HELIOSPHERIC MAGNETIC FIELDS OVER SEVERAL SOLAR CYCLES

    Energy Technology Data Exchange (ETDEWEB)

    Koskela, J. S.; Virtanen, I. I.; Mursula, K., E-mail: jennimari.koskela@oulu.fi [University of Oulu, P.O. Box 3000, FI-90014 Oulu (Finland)

    2017-01-20

    Here we use the PFSS model and photospheric data from Wilcox Solar Observatory, SOHO /MDI, SDO/HMI, and SOLIS to compare the coronal field with heliospheric magnetic field measured at 1 au, compiled in the NASA/NSSDC OMNI 2 data set. We calculate their mutual polarity match and the power of the radial decay, p , of the radial field using different source surface distances and different number of harmonic multipoles. We find the average polarity match of 82% for the declining phase, 78%–79% for maxima, 76%–78% for the ascending phase, and 74%–76% for minima. On an average, the source surface of 3.25 R{sub S} gives the best polarity match. We also find strong evidence for solar cycle variation of the optimal source surface distance, with highest values (3.3 R{sub S}) during solar minima and lowest values (2.6 R{sub S}–2.7 R{sub S}) during the other three solar cycle phases. Raising the number of harmonic terms beyond 2 rarely improves the polarity match, showing that the structure of the HMF at 1 au is most of the time rather simple. All four data sets yield fairly similar polarity matches. Thus, polarity comparison is not affected by photospheric field scaling, unlike comparisons of the field intensity.

  12. A history of solar activity over millennia

    Directory of Open Access Journals (Sweden)

    Ilya G. Usoskin

    2017-03-01

    Full Text Available Abstract Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview of the special indices used to quantify different aspects of variable solar activity, with special emphasis upon sunspot number. Over long timescales, quantitative information about past solar activity can only be obtained using a method based upon indirect proxies, such as the cosmogenic isotopes $$^{14}$$ 14 C and $$^{10}$$ 10 Be in natural stratified archives (e.g., tree rings or ice cores. We give an historical overview of the development of the proxy-based method for past solar-activity reconstruction over millennia, as well as a description of the modern state. Special attention is paid to the verification and cross-calibration of reconstructions. It is argued that this method of cosmogenic isotopes makes a solid basis for studies of solar variability in the past on a long timescale (centuries to millennia during the Holocene. A separate section is devoted to reconstructions of strong solar energetic-particle (SEP events in the past, that suggest that the present-day average SEP flux is broadly consistent with estimates on longer timescales, and that the occurrence of extra-strong events is unlikely. Finally, the main features of the long-term evolution of solar magnetic activity, including the statistics of grand minima and maxima occurrence, are summarized and their possible implications, especially for solar/stellar dynamo theory, are discussed.

  13. 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…

  14. 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...

  15. Q2 anti Q2 states with relatively narrow widths

    International Nuclear Information System (INIS)

    Ono, Seiji.

    1978-09-01

    Using the mass formulas which correctly predict the mass of mesons and baryons the mass of diquark states is computed. From this mass spectrum the existance of the observed narrow baryonia and wide baryonia can be naturally understood. Other relatively narrow Q 2 anti Q 2 states are predicted to exist. (orig.) [de

  16. Horizontal osteotomy for reconstruction of the narrow edentulous mandible

    NARCIS (Netherlands)

    Raghoebar, GM; Batenburg, RHK; Meijer, HJA; Vissink, A

    The aim of this retrospective study was to evaluate the applicability of a horizontal osteotomy procedure for reconstruction of a narrow edentulous mandible in order to enable insertion of implants. In 7 edentulous patients a narrow inferior alveolar ridge was reconstructed with autogenous bone

  17. The solar and interplanetary causes of the recent minimum in geomagnetic activity (MGA23: a combination of midlatitude small coronal holes, low IMF BZ variances, low solar wind speeds and low solar magnetic fields

    Directory of Open Access Journals (Sweden)

    B. T. Tsurutani

    2011-05-01

    Full Text Available Minima in geomagnetic activity (MGA at Earth at the ends of SC23 and SC22 have been identified. The two MGAs (called MGA23 and MGA22, respectively were present in 2009 and 1997, delayed from the sunspot number minima in 2008 and 1996 by ~1/2–1 years. Part of the solar and interplanetary causes of the MGAs were exceptionally low solar (and thus low interplanetary magnetic fields. Another important factor in MGA23 was the disappearance of equatorial and low latitude coronal holes and the appearance of midlatitude coronal holes. The location of the holes relative to the ecliptic plane led to low solar wind speeds and low IMF (Bz variances (σBz2 and normalized variances (σBz2/B02 at Earth, with concomitant reduced solar wind-magnetospheric energy coupling. One result was the lowest ap indices in the history of ap recording. The results presented here are used to comment on the possible solar and interplanetary causes of the low geomagnetic activity that occurred during the Maunder Minimum.

  18. Growth arrest and induction of apoptotic and non-apoptotic programmed cell death by, Physalis minima L. chloroform extract in human ovarian carcinoma Caov-3 cells.

    Science.gov (United States)

    Ooi, Kheng Leong; Muhammad, Tengku Sifzizul Tengku; Sulaiman, Shaida Fariza

    2010-03-02

    The decoction of the whole plant of Physalis minima L. is traditionally consumed to treat cancer. Its anticancer property has been previously verified (using in vitro cytotoxicity assays) against NCI-H23 lung, CORL23 lung and MCF7 breast cancer cell lines but the mechanism underlying the anticancer potency towards ovarian carcinoma cells remain unclear. The present study is aimed to systematically determine the cytotoxicity and possible cell death mechanism elicited by the chloroform extract of Physalis minima in human ovarian Caov-3 carcinoma. Cytotoxicity of the extract was measured using the methylene blue assay. The mechanism of cell death was determined using four independent methods, namely DeadEnd assay to label the DNA fragmentation nuclei cells, RT-PCR analysis to determine the mRNA expression level of three apoptotic genes (c-myc, p53 and caspase-3 genes), Transmission Electron Microscope (TEM) analysis to describe the ultra structural characteristics and annexin V and propidium iodide staining to confirm the types and stages of cell deaths. Cytotoxicity screening of the extract on Caov-3 cells exhibited concentration- and time-dependent inhibitory effects. A combination of apoptotic and autophagic programmed cell death was detected. The apoptotic characteristic was initially determined by DNA fragmentation followed by the expression of c-myc and p53 genes that was much earlier than caspase-3. Apoptotic ultra structural changes (including clumping and magination of chromatin, blebbing and convolution of nucleus membrane and formation of apoptotic bodies) and autophagy (Type II non-apoptotic programmed cell death) with distinct vacuolated morphology were detected in TEM analysis. The existence of these programmed cell deaths was then corroborated using annexin V and propidium iodide staining. The chloroform extract of Physalis minima exerted anticancer effect due to a combination of apoptotic and autophagic cell death mechanisms on Caov-3 cells. The

  19. The influence of solar system oscillation on the variability of the total solar irradiance

    Science.gov (United States)

    Yndestad, Harald; Solheim, Jan-Erik

    2017-02-01

    Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, whereas a non-deterministic variability can only explain the past. This study of solar variability is based on an analysis of two TSI data series, one since 1700 A.D. and one since 1000 A.D.; a sunspot data series since 1610 A.D.; and a solar orbit data series from 1000 A.D. The study is based on a wavelet spectrum analysis. First, the TSI data series are transformed into a wavelet spectrum. Then, the wavelet spectrum is transformed into an autocorrelation spectrum to identify stationary, subharmonic and coincidence periods in the TSI variability. The results indicate that the TSI and sunspot data series have periodic cycles that are correlated with the oscillations of the solar position relative to the barycenter of the solar system, which is controlled by gravity force variations from the large planets Jupiter, Saturn, Uranus and Neptune. A possible explanation for solar activity variations is forced oscillations between the large planets and the solar dynamo. We find that a stationary component of the solar variability is controlled by the 12-year Jupiter period and the 84-year Uranus period with subharmonics. For TSI and sunspot variations, we find stationary periods related to the 84-year Uranus period. Deterministic models based on the stationary periods confirm the results through a close relation to known long solar minima since 1000 A.D. and suggest a modern maximum period from 1940 to 2015. The model computes a new Dalton-type sunspot minimum from approximately 2025 to 2050 and a new Dalton-type period TSI minimum from approximately 2040 to 2065.

  20. Air loads on solar panels during launch

    NARCIS (Netherlands)

    Beltman, W.M.; van der Hoogt, Peter; Spiering, R.M.E.J.; Tijdeman, H.

    1996-01-01

    The dynamical behaviour of solar panels during launch is significantly affected by the thin layers of air trapped between the panels. For narrow gaps the air manifests itself not only as a considerable added mass, but its viscosity can result in a substantial amount of damping. A model has been

  1. 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....

  2. 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.

  3. 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...

  4. Solar Neutrinos

    OpenAIRE

    Antonelli, V.; Miramonti, L.; Peña Garay, Carlos; Serenelli, A.

    2013-01-01

    The study of solar neutrinos has given since ever a fundamental contribution both to astroparticle and to elementary particle physics, offering an ideal test of solar models and offering at the same time relevant indications on the fundamental interactions among particles. After reviewing the striking results of the last two decades, which were determinant to solve the long standing solar neutrino puzzle and refine the Standard Solar Model, we focus our attention on the more recent results in...

  5. Solar holography

    Science.gov (United States)

    Ludman, Jacques E.; Riccobono, Juanita R.; Caulfield, H. John; Upton, Timothy D.

    2002-07-01

    A solar photovoltaic energy collection system using a reflection hologram is described herein. The system uses a single-axis tracking system in conjunction with a spectral- splitting holographic element. The hologram accurately focuses the desired regions of the solar spectrum to match the bandgaps of two ro more different solar cells, while diverting unused IR wavelengths away. Other applications for solar holography include daylighting and greenhouses.

  6. Variation of the Solar Microwave Spectrum in the Last Half Century

    Science.gov (United States)

    Shimojo, Masumi; Iwai, Kazumasa; Asai, Ayumi; Nozawa, Satoshi; Minamidani, Tetsuhiro; Saito, Masao

    2017-10-01

    The total solar fluxes at 1, 2, 3.75, and 9.4 GHz were observed continuously from 1957 to 1994 at Toyokawa, Japan, and from 1994 until now at Nobeyama, Japan, with the current Nobeyama Radio Polarimeters. We examined the multi-frequency and long-term data sets, and found that not only the microwave solar flux but also its monthly standard deviation indicate the long-term variation of solar activity. Furthermore, we found that the microwave spectra at the solar minima of Cycles 20-24 agree with each other. These results show that the average atmospheric structure above the upper chromosphere in the quiet-Sun has not varied for half a century, and suggest that the energy input for atmospheric heating from the sub-photosphere to the corona have not changed in the quiet-Sun despite significantly differing strengths of magnetic activity in the last five solar cycles.

  7. Buying Solar.

    Science.gov (United States)

    Dawson, Joe

    Presented are guidelines for buying solar systems for the individual consumer. This is intended to help the consumer reduce many of the risks associated with the purchase of solar systems, particularly the risks of fraud and deception. Engineering terms associated with solar technology are presented and described to enable the consumer to discuss…

  8. 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

  9. Solar urticaria

    Directory of Open Access Journals (Sweden)

    Srinivas C

    1995-01-01

    Full Text Available A 35-year-old female and a 41-year-old male presented with clinical features suggestive of solar urticaria. The diagnosis of solar urticaria and the effectiveness of a combination of H1 and H2 blocking antihistamines were confirmed by phototesting with a solar simulator

  10. Nonlinear solar cycle forecasting: theory and perspectives

    Directory of Open Access Journals (Sweden)

    A. L. Baranovski

    2008-02-01

    Full Text Available In this paper we develop a modern approach to solar cycle forecasting, based on the mathematical theory of nonlinear dynamics. We start from the design of a static curve fitting model for the experimental yearly sunspot number series, over a time scale of 306 years, starting from year 1700 and we establish a least-squares optimal pulse shape of a solar cycle. The cycle-to-cycle evolution of the parameters of the cycle shape displays different patterns, such as a Gleissberg cycle and a strong anomaly in the cycle evolution during the Dalton minimum. In a second step, we extract a chaotic mapping for the successive values of one of the key model parameters – the rate of the exponential growth-decrease of the solar activity during the n-th cycle. We examine piece-wise linear techniques for the approximation of the derived mapping and we provide its probabilistic analysis: calculation of the invariant distribution and autocorrelation function. We find analytical relationships for the sunspot maxima and minima, as well as their occurrence times, as functions of chaotic values of the above parameter. Based on a Lyapunov spectrum analysis of the embedded mapping, we finally establish a horizon of predictability for the method, which allows us to give the most probable forecasting of the upcoming solar cycle 24, with an expected peak height of 93±21 occurring in 2011/2012.

  11. Nonlinear solar cycle forecasting: theory and perspectives

    Directory of Open Access Journals (Sweden)

    A. L. Baranovski

    2008-02-01

    Full Text Available In this paper we develop a modern approach to solar cycle forecasting, based on the mathematical theory of nonlinear dynamics. We start from the design of a static curve fitting model for the experimental yearly sunspot number series, over a time scale of 306 years, starting from year 1700 and we establish a least-squares optimal pulse shape of a solar cycle. The cycle-to-cycle evolution of the parameters of the cycle shape displays different patterns, such as a Gleissberg cycle and a strong anomaly in the cycle evolution during the Dalton minimum. In a second step, we extract a chaotic mapping for the successive values of one of the key model parameters – the rate of the exponential growth-decrease of the solar activity during the n-th cycle. We examine piece-wise linear techniques for the approximation of the derived mapping and we provide its probabilistic analysis: calculation of the invariant distribution and autocorrelation function. We find analytical relationships for the sunspot maxima and minima, as well as their occurrence times, as functions of chaotic values of the above parameter. Based on a Lyapunov spectrum analysis of the embedded mapping, we finally establish a horizon of predictability for the method, which allows us to give the most probable forecasting of the upcoming solar cycle 24, with an expected peak height of 93±21 occurring in 2011/2012.

  12. Solar cells based on gallium antimonide

    International Nuclear Information System (INIS)

    Andreev, V. M.; Sorokina, S. V.; Timoshina, N. Kh.; Khvostikov, V. P.; Shvarts, M. Z.

    2009-01-01

    Liquid-phase epitaxy and diffusion from the gas phase have been used to create various kinds of GaSb-based solar cell structures intended for use in cascaded solar-radiation converters. A narrow-gap (GaSb) solar cell was studied in tandem based on a combination of semiconductors GaAs-GaSb (two p-n junctions) and GaInP/GaAs-GaSb (three p-n junctions). The maximum efficiency of photovoltaic conversion in GaSb behind the wide-gap cells is η = 6.5% (at sunlight concentration ratio of 275X, AM1.5D Low AOD spectrum).

  13. Solar total irradiance in cycle 23

    Science.gov (United States)

    Krivova, N. A.; Solanki, S. K.; Schmutz, W.

    2011-05-01

    Context. The most recent minimum of solar activity was deeper and longer than the previous two minima as indicated by different proxies of solar activity. This is also true for the total solar irradiance (TSI) according to the PMOD composite. Aims: The apparently unusual behaviour of the TSI has been interpreted as evidence against solar surface magnetism as the main driver of the secular change in the TSI. We test claims that the evolution of the solar surface magnetic field does not reproduce the observed TSI in cycle 23. Methods: We use sensitive, 60-min averaged MDI magnetograms and quasi-simultaneous continuum images as an input to our SATIRE-S model and calculate the TSI variation over cycle 23, sampled roughly every two weeks. The computed TSI is then compared with the PMOD composite of TSI measurements and with the data from two individual instruments, SORCE/TIM and UARS/ACRIM II, that monitored the TSI during the declining phase of cycle 23 and over the previous minimum in 1996, respectively. Results: Excellent agreement is found between the trends shown by the model and almost all sets of measurements. The only exception is the early, i.e. 1996 to 1998, PMOD data. Whereas the agreement between the model and the PMOD composite over the period 1999-2009 is almost perfect, the modelled TSI shows a steeper increase between 1996 and 1999 than implied by the PMOD composite. On the other hand, the steeper trend in the model agrees remarkably well with the ACRIM II data. A closer look at the VIRGO data, which are the basis of the PMOD composite after 1996, reveals that only one of the two VIRGO instruments, the PMO6V, shows the shallower trend present in the composite, whereas the DIARAD measurements indicate a steeper trend. Conclusions: Based on these results, we conclude that (1) the sensitivity changes of the PMO6V radiometers within VIRGO during the first two years have very likely not been correctly evaluated; and that (2) the TSI variations over cycle 23

  14. Narrowband shortwave minima in spectra of backscattered light from the sea obtained from ocean color scanners as a remote indication of algal blooms

    Directory of Open Access Journals (Sweden)

    G.S. Karabashev

    2016-10-01

    Full Text Available We propose a new approach to indication of algal blooms. It stems from analysis of the multispectral satellite reflectance Rrs of areas where blooms were documented during recent decades. We found that spectra of algal blooms exhibit minima at wavelengths of channels of Moderate Resolution Imaging Spectroradiometer (MODIS λ = 443 and λ = 488 nm (Baltic, Black, and Caspian seas, λ = 443 nm (Southwest Tropical Pacific (SWTP, and λ = 443 nm and λ = 469 nm (Patagonian Continental Shelf (PCS, attributable to absorption bands of chlorophyll a and accessory pigments. We quantified the minima using indices D1 = Rrs(443 − Rrs(412 and D2 = Rrs(488 − Rrs(469 and proved their diagnostic potential by comparing their distributions to that of Rrs(555. Linear dependence of D1 upon chlorophyll a was found from MODIS data for the bloom of Nodularia spumigena. Time dependences of D1 and D2 point to the latter as a probable remote forerunner of cyanobacterial blooms. In the PCS, D1 and D2 proved to be too simplistic owing to diversity of spectral shapes at λ < 550 nm. Cluster analysis revealed close linkage of the latter and local oceanological conditions. Our findings bear witness to the diagnostic potential of the indices by virtue of their direct relation to pigment absorption and because the broadband background reflectance changes reduce when calculating the indices as a difference of spectrally close reflectances. Further studies are needed to convert the indices to band-difference algorithms for retrieving the bio-optical characteristics of algal blooms.

  15. Identification of up-regulated genes from the metal-hyperaccumulator aquatic fern Salvinia minima Baker, in response to lead exposure.

    Science.gov (United States)

    Leal-Alvarado, Daniel A; Martínez-Hernández, A; Calderón-Vázquez, C L; Uh-Ramos, D; Fuentes, G; Ramírez-Prado, J H; Sáenz-Carbonell, L; Santamaría, J M

    2017-12-01

    Lead (Pb) is one of the most serious environmental pollutants. The aquatic fern Salvinia minima Baker is capable to hyper-accumulate Pb in their tissues. However, the molecular mechanisms involved in its Pb accumulation and tolerance capacity are not fully understood. In order to investigate the molecular mechanisms that are activated by S. minima in response to Pb, we constructed a suppression subtractive hybridization library (SSH) in response to an exposure to 40μM of Pb(NO 3 ) 2 for 12h. 365 lead-related differentially expressed sequences tags (ESTs) were isolated and sequenced. Among these ESTs, 143 unique cDNA (97 were registered at the GenBank and 46 ESTs were not registered, because they did not meet the GenBank conditions). Those ESTs were identified and classified into 3 groups according to Blast2GO. In terms of metabolic pathways, they were grouped into 29 KEGG pathways. Among the ESTs, we identified some that might be part of the mechanism that this fern may have to deal with this metal, including abiotic-stress-related transcription factors, some that might be involved in tolerance mechanisms such as ROS scavenging, membrane protection, and those of cell homeostasis recovery. To validate the SSH library, 4 genes were randomly selected from the library and analyzed by qRT-PCR. These 4 genes were transcriptionally up-regulated in response to lead in at least one of the two tested tissues (roots and leaves). The present library is one of the few genomics approaches to study the response to metal stress in an aquatic fern, representing novel molecular information and tools to understand the molecular physiology of its Pb tolerance and hyperaccumulation capacity. Further research is required to elucidate the functions of the lead-induced genes that remain classified as unknown, to perhaps reveal novel molecular mechanisms of Pb tolerance and accumulation capacity in aquatic plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. LONG-TERM TREND OF SOLAR CORONAL HOLE DISTRIBUTION FROM 1975 TO 2014

    Energy Technology Data Exchange (ETDEWEB)

    Fujiki, K.; Tokumaru, M.; Hayashi, K.; Satonaka, D. [Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa, Nagoya Aichi 464-8601 (Japan); Hakamada, K., E-mail: fujiki@isee.nagoya-u.ac.jp [Department of Natural Science and Mathematics, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)

    2016-08-20

    We developed an automated prediction technique for coronal holes using potential magnetic field extrapolation in the solar corona to construct a database of coronal holes appearing from 1975 February to 2015 July (Carrington rotations from 1625 to 2165). Coronal holes are labeled with the location, size, and average magnetic field of each coronal hole on the photosphere and source surface. As a result, we identified 3335 coronal holes and found that the long-term distribution of coronal holes shows a similar pattern known as the magnetic butterfly diagram, and polar/low-latitude coronal holes tend to decrease/increase in the last solar minimum relative to the previous two minima.

  17. 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...

  18. Solar Cycle Variability Induced by Tilt Angle Scatter in a Babcock-Leighton Solar Dynamo Model

    Science.gov (United States)

    Karak, Bidya Binay; Miesch, Mark

    2017-09-01

    We present results from a three-dimensional Babcock-Leighton (BL) dynamo model that is sustained by the emergence and dispersal of bipolar magnetic regions (BMRs). On average, each BMR has a systematic tilt given by Joy’s law. Randomness and nonlinearity in the BMR emergence of our model produce variable magnetic cycles. However, when we allow for a random scatter in the tilt angle to mimic the observed departures from Joy’s law, we find more variability in the magnetic cycles. We find that the observed standard deviation in Joy’s law of {σ }δ =15^\\circ produces a variability comparable to the observed solar cycle variability of ˜32%, as quantified by the sunspot number maxima between 1755 and 2008. We also find that tilt angle scatter can promote grand minima and grand maxima. The time spent in grand minima for {σ }δ =15^\\circ is somewhat less than that inferred for the Sun from cosmogenic isotopes (about 9% compared to 17%). However, when we double the tilt scatter to {σ }δ =30^\\circ , the simulation statistics are comparable to the Sun (˜18% of the time in grand minima and ˜10% in grand maxima). Though the BL mechanism is the only source of poloidal field, we find that our simulations always maintain magnetic cycles even at large fluctuations in the tilt angle. We also demonstrate that tilt quenching is a viable and efficient mechanism for dynamo saturation; a suppression of the tilt by only 1°-2° is sufficient to limit the dynamo growth. Thus, any potential observational signatures of tilt quenching in the Sun may be subtle.

  19. What's in a name? Expiratory tracheal narrowing in adults explained

    International Nuclear Information System (INIS)

    Leong, P.; Bardin, P.G.; Lau, K.K.

    2013-01-01

    Tracheomalacia, tracheobronchomalacia, and excessive dynamic airway collapse are all terms used to describe tracheal narrowing in expiration. The first two describe luminal reduction from cartilage softening and the latter refers to luminal reduction from exaggerated posterior membrane movement. Expiratory tracheal narrowing is a frequent occurrence that can cause symptoms of airway obstruction, such as dyspnoea, wheeze, and exercise intolerance. The accurate diagnosis and quantification of expiratory tracheal narrowing has important aetiological, therapeutic, and prognostic implications. The reference standard for diagnosis has traditionally been bronchoscopy; however, this method has significant limitations. Expiratory tracheal disorders are readily detected by four-dimensional dynamic volume multidetector computed tomography (4D-CT), an emerging, non-invasive method that will potentially enable detection and quantification of these conditions. This review discusses the morphological forms of expiratory tracheal narrowing and demonstrates the utility of 4D-CT in the diagnosis, quantification, and treatment of these important conditions

  20. Vascular narrowing in pulmonary arterial hypertension is heterogeneous: rethinking resistance

    NARCIS (Netherlands)

    Rol, N.; Timmer, E.M.; Faes, T.J.; Noordegraaf, A.V.; Grunberg, K.; Bogaard, H.J.; Westerhof, N.

    2017-01-01

    In idiopathic pulmonary arterial hypertension (PAH), increased pulmonary vascular resistance is associated with structural narrowing of small (resistance) vessels and increased vascular tone. Current information on pulmonary vascular remodeling is mostly limited to averaged increases in wall

  1. Single frequency narrow linewidth 2 micron laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for coherent Lidar applications. The laser should be tunable by several nm and frequency...

  2. Subglottic cysts and asymmetrical subglottic narrowing on neck radiograph

    International Nuclear Information System (INIS)

    Holinger, L.D.; Torium, D.M.; Anandappa, E.C.

    1988-01-01

    The congenital subglottic hemangioma typically appears as an asymmetric subglottic narrowing or mass on frontal neck radiograph. Therefore, soft tissue neck radiography has been advocated as a definitive non-operative approach for diagnosing these lesions. However, we have noted similar asymmetric subglottic narrowing in patients with acquired subglottic cysts. These retention cysts occur following long-term intubation in the neonate. The mechanism probably involves subglottic fibrosis which obstructs glands with subsequent cyst formation. Acquired subglottic cysts typically appear as an asymmetric narrowing on frontal or lateral soft tissue neck radiographs. These lesions may produce airway compromise but are effectively treated by forceps or laser removal. Acquired subglottic cysts must be included in the differential diagnosis of asymmetric subglottic narrowing. The definitive diagnosis is made by direct laryngoscopy, not soft tissue neck radiograph. (orig.)

  3. Integrating narrow therapeutic index drug formulations in transplantation

    NARCIS (Netherlands)

    A. Johnston (Andrew); L. Schick (Liz); T. van Gelder (Teun)

    2012-01-01

    textabstractThere is considerable debate regarding generic drug substitution in solid organ transplant recipients, and various European transplant associations and societies have expressed caution about the potential adverse consequences from uncontrolled switching between the different narrow

  4. Narrow-Band Bandpass Filter for Wireless Communication System

    Science.gov (United States)

    Kishor, Jugul; Kanaujia, Binod K.; Dwari, Santanu; Ashwani, Kumar

    2017-07-01

    This paper presents the design of a compact narrow-band bandpass filter using the cylindrical dielectric resonator (CDR) coupled with a microstrip line. The TE11δ mode of the dielectric resonator is used to obtain the narrow passband performance while, spurious mode suppression can be improved by etching the slot on the ground plane of the filter due to mode separation with the desired mode. Presented narrow bandpass filter performances are: center frequency 6.15 GHz, fractional bandwidth 0.7 %, and insertion loss (IL) 0.16 dB. To validate the above concept a second order narrow-band bandpass filter is designed, fabricated and measured. There is good agreement between simulated and measured results.

  5. NARROW READING IN AN EXTENSIVE READING COURSE: LEXICALLY-BASED

    Directory of Open Access Journals (Sweden)

    Siusana Kweldju

    2016-02-01

    Full Text Available One shot case study was conducted in one semester to undergraduate English majors who were preparing themselves to become English teachers at high school level. This study was to find out whether or not students had positive attitudes towards narrow reading, how high narrow reading helped them improve their English proficiency, and what problems students might have with narrow reading. Four questionnaires were completed during the case study to discover how students felt and thought about the course and how the course improved their English. It was found out that narrow reading not only improved students' language proficiency but also helped students develop their general knowledge, the love of reading and the appreciation on literary work.

  6. Current status on narrow N anti N states

    International Nuclear Information System (INIS)

    Chung, S.U.

    1979-09-01

    An attempt is made to summarize the experimental status of narrow B anti B states as of mid-1979. In particular, concentration is placed on the current experimental situations and prospects regarding three serious contenders for the so-called baryonium states. Theoretical concepts of baryoniums, narrow N anti N states known as S(1935), anti pp(2020), and anti pp(2204), and some forthcoming results, and problems of the above three resonances are discussed. 31 references

  7. An analysis of interplanetary space radiation exposure for various solar cycles

    International Nuclear Information System (INIS)

    Badhwar, G.D.; O'Neill, P.M.; Cucinotta, F.A.

    1994-01-01

    The radiation dose received by crew members in interplanetary space is influenced by the stage of the solar cycle. Using the recently developed models of the galactic cosmic radiation (GCR) environment and the energy-dependent radiation transport code, we have calculated the dose at 0 and 5 cm water depth; using a computerized anatomical man (CAM) model, we have calculated the skin, eye and blood-forming organ (BFO) doses as a function of aluminum shielding for various solar minima and maxima between 1954 and 1989. These results show that the equivalent dose is within about 15% of the mean for the various solar minima (maxima). The maximum variation between solar minimum and maximum equivalent dose is about a factor of three. We have extended these calculations for the 1967-1977 solar minimum to five practical shielding geometries: Apollo Command Module, the least and most heavily shielded locations in the U.S. space shuttle mid-deck, center of the proposed Space Station Freedom cluster and sleeping compartment of the Skylab. These calculations, using the quality factor of ICRP 60, show that the average CAM BFO equivalent dose is 0.46 Sv/year. Based on an approach that takes fragmentation into account, we estimate a calculation uncertainty of 15% if the uncertainty in the quality factor is neglected. 25 refs., 11 figs., 1 tab

  8. A CHF Model in Narrow Gaps under Saturated Boiling

    International Nuclear Information System (INIS)

    Park, Suki; Kim, Hyeonil; Park, Cheol

    2014-01-01

    Many researchers have paid a great attention to the CHF in narrow gaps due to enormous industrial applications. Especially, a great number of researches on the CHF have been carried out in relation to nuclear safety issues such as in-vessel retention for nuclear power plants during a severe accident. Analytical studies to predict the CHF in narrow gaps have been also reported. Yu et al. (2012) developed an analytical model to predict the CHF on downward facing and inclined heaters based on the model of Kandlikar et al. (2001) for an upward facing heater. A new theoretical model is developed to predict the CHF in narrow gaps under saturated pool boiling. This model is applicable when one side of coolant channels or both sides are heated including the effects of heater orientation. The present model is compared with the experimental CHF data obtained in narrow gaps. A new analytical CHF model is proposed to predict CHF for narrow gaps under saturated pool boiling. This model can be applied to one-side or two-sides heating surface and also consider the effects of heater orientation on CHF. The present model is compared with the experimental data obtained in narrow gaps with one heater. The comparisons indicate that the present model shows a good agreement with the experimental CHF data in the horizontal annular tubes. However, it generally under-predicts the experimental data in the narrow rectangular gaps except the data obtained in the gap thickness of 10 mm and the horizontal downward facing heater

  9. Solar magnetohydrodynamics

    International Nuclear Information System (INIS)

    Priest, E.R.

    1982-01-01

    The book serves several purposes. First set of chapters gives a concise general introduction to solar physics. In a second set the basic methods of magnetohydrodynamics are developed. A third set of chapters is an account of current theories for observed phenomena. The book is suitable for a course in solar physics and it also provides a comprehensive review of present magnetohydrodynamical models in solar physics. (SC)

  10. Solar Simulator

    Science.gov (United States)

    1981-01-01

    Oriel Corporation's simulators have a high pressure xenon lamp whose reflected light is processed by an optical system to produce a uniform solar beam. Because of many different types of applications, the simulators must be adjustable to replicate many different areas of the solar radiation spectrum. Simulators are laboratory tools for such purposes as testing and calibrating solar cells, or other solar energy systems, testing dyes, paints and pigments, pharmaceuticals and cosmetic preparations, plant and animal studies, food and agriculture studies and oceanographic research.

  11. Solar small-scale dynamo and polarity of sunspot groups

    Science.gov (United States)

    Sokoloff, D.; Khlystova, A.; Abramenko, V.

    2015-08-01

    In order to clarify a possible role of small-scale dynamo in formation of solar magnetic field, we suggest an observational test for small-scale dynamo action based on statistics of anti-Hale sunspot groups. As we have shown, according to theoretical expectations the small-scale dynamo action has to provide a population of sunspot groups which do not follow the Hale polarity law, and the density of such groups on the time-latitude diagram is expected to be independent on the phase of the solar cycle. Correspondingly, a percentage of the anti-Hale groups is expected to reach its maximum values during solar minima. For several solar cycles, we considered statistics of anti-Hale groups obtained by several scientific teams, including ours, to find that the percentage of anti-Hale groups becomes indeed maximal during a solar minimum. Our interpretation is that this fact may be explained by the small-scale dynamo action inside the solar convective zone.

  12. NARROW-LINE-WIDTH UV BURSTS IN THE TRANSITION REGION ABOVE SUNSPOTS OBSERVED BY IRIS

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Zhenyong; Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S.; Fu, Hui; Mou, Chaozhou; Xie, Haixia, E-mail: z.huang@sdu.edu.cn, E-mail: xld@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong (China)

    2016-10-01

    Various small-scale structures abound in the solar atmosphere above active regions, playing an important role in the dynamics and evolution therein. We report on a new class of small-scale transition region structures in active regions, characterized by strong emissions but extremely narrow Si iv line profiles as found in observations taken with the Interface Region Imaging Spectrograph (IRIS). Tentatively named as narrow-line-width UV bursts (NUBs), these structures are located above sunspots and comprise one or multiple compact bright cores at sub-arcsecond scales. We found six NUBs in two data sets (a raster and a sit-and-stare data set). Among these, four events are short-lived with a duration of ∼10 minutes, while two last for more than 36 minutes. All NUBs have Doppler shifts of 15–18 km s{sup −1}, while the NUB found in sit-and-stare data possesses an additional component at ∼50 km s{sup −1} found only in the C ii and Mg ii lines. Given that these events are found to play a role in the local dynamics, it is important to further investigate the physical mechanisms that generate these phenomena and their role in the mass transport in sunspots.

  13. Narrow-line-width UV Bursts in the Transition Region above Sunspots Observed by IRIS

    Science.gov (United States)

    Hou, Zhenyong; Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S.; Fu, Hui; Mou, Chaozhou; Xie, Haixia

    2016-10-01

    Various small-scale structures abound in the solar atmosphere above active regions, playing an important role in the dynamics and evolution therein. We report on a new class of small-scale transition region structures in active regions, characterized by strong emissions but extremely narrow Si IV line profiles as found in observations taken with the Interface Region Imaging Spectrograph (IRIS). Tentatively named as narrow-line-width UV bursts (NUBs), these structures are located above sunspots and comprise one or multiple compact bright cores at sub-arcsecond scales. We found six NUBs in two data sets (a raster and a sit-and-stare data set). Among these, four events are short-lived with a duration of ˜10 minutes, while two last for more than 36 minutes. All NUBs have Doppler shifts of 15-18 km s-1, while the NUB found in sit-and-stare data possesses an additional component at ˜50 km s-1 found only in the C II and Mg II lines. Given that these events are found to play a role in the local dynamics, it is important to further investigate the physical mechanisms that generate these phenomena and their role in the mass transport in sunspots.

  14. Ultra-narrow band perfect absorbers based on Fano resonance in MIM metamaterials

    Science.gov (United States)

    Zhang, Ming; Fang, Jiawen; Zhang, Fei; Chen, Junyan; Yu, Honglin

    2017-12-01

    Metallic nanostructures have attracted numerous attentions in the past decades due to their attractive plasmonic properties. Resonant plasmonic perfect absorbers have promising applications in a wide range of technologies including photothermal therapy, thermophotovoltaics, heat-assisted magnetic recording and biosensing. However, it remains to be a great challenge to achieve ultra-narrow band in near-infrared band with plasmonic materials due to the large optical losses in metals. In this letter, we introduced Fano resonance in MIM metamaterials composed of an asymmetry double elliptic cylinders (ADEC), which can achieve ultra-narrow band perfect absorbers. In theoretical calculations, we observed an ultranarrow band resonant absorption peak with the full width at half maximum (FWHM) of 8 nm and absorption amplitude exceeding 99% at 930 nm. Moreover, we demonstrate that the absorption increases with the increase of asymmetry and the absorption resonant wavelength can be tuned by changing the size and arrangement of the unit cell. The asymmetry metallic nanostructure also exhibit a higher refractive sensitivity as large as 503 nm/RIU with high figure of merit of 63, which is promising for high sensitive sensors. Results of this work are desirable for various potential applications in micro-technological structures such as biological sensors, narrowband emission, photodetectors and solar thermophotovoltaic (STPV) cells.

  15. Multilayer Photonic Crystal for Spectral Narrowing of Emission

    Directory of Open Access Journals (Sweden)

    Zhanfang LIU

    2017-08-01

    Full Text Available Multilayer colloidal crystal has been prepared by the layer-by-layer deposition of silica microspheres on a glass slide. Each layer is a slab consisting of a fcc close-packed colloidal arrays. By properly choosing the sizes of spheres, the whole spectral feature of multilayer colloidal crystal can be tuned. Here, we engineered a multilayer superlattice structure with an effective passband between two stop bands. This gives a strong narrowing effect on emission spectrum. With the stop bands at the shortwave and longwave edges of emission spectrum, the passband in the central wavelength region can be regarded as a strong decrease of suppression effect and enhancement of a narrow wavelength region of emission. The spectral narrowing modification effect of suitably engineered colloidal crystals shows up their importance in potential application as optical filters and lasing devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16320

  16. CT demonstration of pharyngeal narrowing in adult obstructive sleep apnea

    Energy Technology Data Exchange (ETDEWEB)

    Bohlman, M.E. (Johns Hopkins Univ. School of Medicine, Baltimore, MD); Haponik, E.F.; Smith, P.L.; Allen, R.P.; Bleecker, E.R.; Goldman, S.M.

    1983-03-01

    Sleep apnea is a major cause of daytime hypersomnolence. Among the proposed etiologies, focal obstruction of the airways at the level of the pharynx has been suggested but not proven. Using computed tomography, the cross-sectional area of the airway can be readily assessed. Thirty-three adults with clinically proven sleep apnea and 12 normal adults underwent systematic computed tomography of the neck. Significant airway narrowing was demonstrated in all the patients with obstructive sleep apnea, whereas no such narrowing was seen in the controls. In 11, the narrowing was at a single level, whereas in 22 patients two or more levels were affected. This study has shown that a structurally abnormal airway may serve as an anatomic substrate for the development of sleep apnea. On the basis of this evidence, uvulopalatopharyngoplasty has been performed in two patients with relief of symptoms in one.

  17. CT demonstration of pharyngeal narrowing in adult obstructive sleep apnea

    International Nuclear Information System (INIS)

    Bohlman, M.E.; Haponik, E.F.; Smith, P.L.; Allen, R.P.; Bleecker, E.R.; Goldman, S.M.

    1983-01-01

    Sleep apnea is a major cause of daytime hypersomnolence. Among the proposed etiologies, focal obstruction of the airways at the level of the pharynx has been suggested but not proven. Using computed tomography, the cross-sectional area of the airway can be readily assessed. Thirty-three adults with clinically proven sleep apnea and 12 normal adults underwent systematic computed tomography of the neck. Significant airway narrowing was demonstrated in all the patients with obstructive sleep apnea, whereas no such narrowing was seen in the controls. In 11, the narrowing was at a single level, whereas in 22 patients two or more levels were affected. This study has shown that a structurally abnormal airway may serve as an anatomic substrate for the development of sleep apnea. On the basis of this evidence, uvulopalatopharyngoplasty has been performed in two patients with relief of symptoms in one

  18. Solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wendel, W.

    1977-03-03

    A solar collector is described. The absorber consists of a plate onto which the light is focussed through lenses. The heat is transported from the absorber to the heat accumulator via metallic heat conductors. In case of insufficient solar radiation, the heat transport from the collector to the accumulator may be interrupted by a disconnecting switch. The casing consists of Eternit.

  19. Solar Sprint

    Science.gov (United States)

    Tabor, Richard; Anderson, Stephen

    2007-01-01

    In the "Solar Sprint" activity, students design, test, and race a solar-powered car built with Legos. The use of ratios is incorporated to simulate the actual work of scientists and engineers. This method encourages fourth-grade students to think about multiple variables and stimulates their curiosity when an activity doesn't come out as…

  20. Solar cooking

    Science.gov (United States)

    Over two billion people face fuel wood shortages, causing tremendous personal and environmental stress. Over 4 million people die prematurely from indoor air pollution. Solar cooking can reduce fuel wood consumption and indoor air pollution. Solar cooking has been practiced and published since th...

  1. Preparation of polyamide microcapsules having narrow size distributions.

    Science.gov (United States)

    Muramatsu, N; Shiga, K; Kondo, T

    1994-01-01

    A novel emulsification technique which employs microporous glass membranes was adopted to prepare polyamide microcapsules of narrow size distribution. This technique proved to be simple and quite efficient for getting fairly uniform sizes of dispersed liquid droplets. Polyamide microcapsules prepared by using this technique were found not completely monodisperse, but far more satisfactory than those by any conventional mechanical methods in view of their narrow size distribution. This method also seems promising to get various sizes of the capsules by selecting the pore size of the glass membranes.

  2. Narrow-width mechanism of a=5 Ξ-state

    International Nuclear Information System (INIS)

    Kumagai-Fuse, I.; Akaishi, Y.

    1995-04-01

    Narrow-width mechanism of ≡ 5 H is discussed by calculating conversion widths to all its possible decay channels. Since the conversion processes have small reaction Q values, the three- and four- body decays are strongly suppressed owing to small phase volumes available. Decay widths to the two-body channels are significantly reduced by the distortion of emitted-particle waves. This mechanism brings about a narrow width of ≡ 5 H. The total width is estimated to be 0.87 MeV, in which the largest contribution comes from the decay into the Λ 4 H * +Λ channel. (author)

  3. The exchange narrowing of T1 in solid helium-3

    International Nuclear Information System (INIS)

    Matsumoto, Kazuyuki; Abe, Takayuki; Izuyama, Takeo.

    1989-01-01

    The exchange narrowing of the nuclear magnetic relaxation time T 1 of bcc 3 He is investigated. it is found that multiple exchange models with two and three parameters may explain the T 1 data observed in the region 0.2 m = 24.2 cm 3 /mol. We investigate further the narrowing in hcp 3 He. Based on the multiple exchange model with the exchange parameters J 1 , J 1 ', J 2 , and K sq , we obtain a theoretical expression for T 1 . (author)

  4. Solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Moriaki; Hayashibara, Mitsuo

    1988-08-18

    Concerning the exsisting solar cell utilizing wavelength transition, the area of the solar cell element necessary for unit electric power output can be made small, but transition efficiency of the solar cell as a whole including a plastic plate with phosphor is not high. This invention concerns a solar cell which is appropriate for transferring the light within a wide spectrum range of the sunlight to electricilty efficiently, utilizes wavelength transition and has high efficiency per unit area. In other words, the solar cell of this invention has the feature of providing in parallel with a photoelectric transfer layer a layer of wavelength transitioning material (phosphor) which absorbs the light within the range of wavelength of low photoelectric transfer efficiency at the photoelectric transfer layer and emits the light within the range of wavelength in which the photoelectric transfer rate is high on the light incident side of the photoelectric transfer layer. (5 figs)

  5. Spectral light management for solar energy conversion systems

    Science.gov (United States)

    Stanley, Cameron; Mojiri, Ahmad; Rosengarten, Gary

    2016-06-01

    Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  6. Spectral light management for solar energy conversion systems

    Directory of Open Access Journals (Sweden)

    Stanley Cameron

    2016-06-01

    Full Text Available Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  7. Statistics of the largest sunspot and facular areas per solar cycle

    International Nuclear Information System (INIS)

    Willis, D.M.; Kabasakal Tulunay, Y.

    1979-01-01

    The statistics of extreme values is used to investigate the statistical properties of the largest areas sunspots and photospheric faculae per solar cycle. The largest values of the synodic-solar-rotation mean areas of umbrae, whole spots and faculae, which have been recorded for nine solar cycles, are each shown to comply with the general form of the extreme value probability function. Empirical expressions are derived for the three extreme value populations from which the characteristic statistical parameters, namely the mode, median, mean and standard deviation, can be calculated for each population. These three extreme value populations are also used to find the expected ranges of the extreme areas in a group of solar cycles as a function of the number of cycles in the group. The extreme areas of umbrae and whole spots have a dispersion comparable to that found by Siscoe for the extreme values of sunspot number, whereas the extreme areas of faculae have a smaller dispersion which is comparable to that found by Siscoe for the largest geomagnetic storm per solar cycle. The expected range of the largest sunspot area per solar cycle for a group of one hundred cycles appears to be inconsistent with the existence of the prolonged periods of sunspot minima that have been inferred from the historical information on solar variability. This inconsistency supports the contention that there are temporal changes of solar-cycle statistics during protracted periods of sunspot minima (or maxima). Indeed, without such temporal changes, photospheric faculae should have been continually observable throughout the lifetime of the Sun. (orig.)

  8. Solar thermal

    International Nuclear Information System (INIS)

    Jones, J.

    2006-01-01

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m 3 - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become increasingly important as

  9. Solar energy: photovoltaics

    International Nuclear Information System (INIS)

    Goetzberger, A.; Voss, B.; Knobloch, J.

    1994-01-01

    This textbooks covers the following topics: foundations of photovoltaics, solar energy, P-N junctions, physics of solar cells, high-efficiency solar cells, technology of Si solar cells, other solar cells, photovoltaic applications. (orig.)

  10. Stories About Maxima and Minima

    Indian Academy of Sciences (India)

    mathematical olympiad. The topic of the session was 'Mathematical Analysis'. To demonstrate the power of mathematical analysis, I decided to tell the students about topics that you have ... Second Edition, which was reviewed in Resonance, April 1999, p.96 has been published by Foundation Books, New Delhi,. 1998.

  11. Predicting soil nitrogen content using narrow-band indices from ...

    African Journals Online (AJOL)

    Optimal fertiliser applications for sustainable forest stand productivity management, whilst protecting the environment, is vital. This study estimated soil nitrogen content using leaf-level narrow-band vegetation indices derived from a hand-held 350–2 500 nm spectroradiometer. Leaf-level spectral data were collected and ...

  12. Reduced dosages of atrazine and narrow rows can provide ...

    African Journals Online (AJOL)

    hope&shola

    2010-11-08

    Nov 8, 2010 ... of reduced herbicide dosages and narrow rows to achieve adequate weed control and optimise on yields in smallholder farming systems. Key words: Row spacing, reduced atrazine dosages, weed density, weed biomass, maize yield. INTRODUCTION. Inadequate weed control is one of the major causes of.

  13. Japanese VLBI Network Observations of a Gamma-Ray Narrow ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We made simultaneous single-dish and VLBI observations of a gamma-ray narrow-line Seyfert 1 (NLS1) galaxy 1H 0323+342. We found significant flux variation at 8 GHz on a ... Institute for Cosmic Ray Research, The University of Tokyo, Chiba 277-8582, Japan. The Institute of Space and Astronautical ...

  14. A "Narrowing of Inquiry" in American Moral Psychology and Education

    Science.gov (United States)

    Richardson, Michael J.; Slife, Brent D.

    2013-01-01

    We explore the possibility that a priori philosophical commitments continue to result in a narrowing of inquiry in moral psychology and education where theistic worldviews are concerned. Drawing from the theories of Edward L. Thorndike and John Dewey, we examine naturalistic philosophical commitments that influenced the study of moral psychology…

  15. Note: Folded optical system for narrow forward looking probe

    International Nuclear Information System (INIS)

    Hou, Hsuan-Chao; Hah, Dooyoung; Kim, Jeonghwan; Feldman, M.

    2014-01-01

    An optical system is described in which a laser beam makes three passes through a single graded index lens, forming a focus along the optic axis. It has important applications in endoscopic probes, where the forward looking characteristic permits the avoidance of obstacles and the narrow structure makes it minimally invasive

  16. Career Attainment among Healthcare Executives: Is the Gender Gap Narrowing?

    Science.gov (United States)

    Branin, Joan Julia

    2009-01-01

    Health care occupations are expected to be among the fastest growing professions in the next ten years. With such incredible growth expected in employment and wages, and with women's participation in the industry remaining strong, are women in the health care industry, particularly those in health care administration, experiencing a narrowing of…

  17. Measurements of Narrow Mg II Associated Absorption Doublets with ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The measurement of the variations of absorption lines over time is a good method to study the physical conditions of absorbers. In this paper, we measure the variations of the line strength of 36 narrow Mg II2796, 2803 associated absorption doublets, which are imprinted on 31 quasar spectra with two ...

  18. World Food Resources and Population: The Narrowing Margin.

    Science.gov (United States)

    Brown, Lester R.

    1981-01-01

    This bulletin examines the narrowing margin between global food production and population growth. Between 1950 and 1971, world grain production nearly doubled and per capita production increased 31 percent. During the 1970s, gains in output barely kept pace with population growth, consumption per person declined in sub-Saharan Africa and parts of…

  19. Synthesis of iron oxide nanoparticles of narrow size distribution on ...

    Indian Academy of Sciences (India)

    WINTEC

    Interaction between iron (II) sulfate and template has been carried out in aqueous phase, followed by the selective and controlled removal of the template to achieve narrow distribution of ... templates like aluminium oxide, carbon nanotubes, sur- factants, polymer fibres and egg shell membranes have been employed.

  20. Harmonic Generation and Linewidth Narrowing in Seeded FELs

    CERN Document Server

    Giannessi, Luca

    2004-01-01

    The process of harmonic generation in a seeded single pass Free Electron Laser are studied in the time/frequency domain. The linewidth narrowing of the fundamental harmonic is correlated to the amplitude of the input seed. The spectral evolution of the harmonics is studied within a self consistent time dependent model.

  1. Qualification of submerged-arc narrow strip cladding process

    International Nuclear Information System (INIS)

    Ayres, P.S.; Gottschling, J.D.; Jeffers, G.K.

    1975-08-01

    An unique narrow strip cladding process for use on both plate and forging material for nuclear components was developed. The qualification testing of this low-heat input process for cladding nuclear components, including those of SA508 Class 2 material is described. The theory that explains the acceptable results of these tests is also given. (auth)

  2. Qualification of submerged-arc narrow strip cladding process

    International Nuclear Information System (INIS)

    Ayres, P.S.; Gottschling, J.D.; Jeffers, G.K.

    1976-03-01

    Babcock and Wilcox has developed an unique narrow strip cladding process for use on both plate and forging material for nuclear components. The qualification testing of this low-heat input process for cladding nuclear components is described, including those of SA508 Class 2 material. The theory that explains the acceptable results of these tests is also given

  3. Extrinsic stretching narrowing and anterior indentation of the rectosigmoid junction

    International Nuclear Information System (INIS)

    Schulman, A.; Fataar, S.

    1979-01-01

    Thirty-five cases of extrinsic narrowing or anterior indentation of the rectosigmoid junction (RSJ) have been studied. The RSJ lies directly behind the pouch of Douglas which is a favoured site for peritoneal metastasis, abscess and endometriosis. Any space-occupying lesion of sufficient size at this site will indent the anterior aspects of the RSJ. Causes include distension or tumour of the ileum or sigmoid colon, gross ascites (when the patient is erect), and tumours below the pelvic peritonium, such as gynaecological neoplasm and internal iliac artery aneurysm. When a desmoplastic metastasis in the pouch of Douglas infiltrates the outer layers of the RSJ, the fibrosis produces an eccentric shortening on its anterior aspect, which in turn causes a pleating of the mucosa with the folds radiating towards the shortened area. This is also seen with primary pelvic carcinomas directly adherent to the rectum, endometriosis with repeated bleeding and increasing eccentric, submucosal fibrosis, and chronic abscess in the pouch of Douglas. Not all extrinsic narrowing of the RSJ are pathological. One case of anterior indentation followed operation for rectal prolapse. Ten additional cases showed narrowing due to a technical artefact air-distended colon rising into the upper abdomen to cause stretching at the RSJ. As with ascites, this narrowing due to 'high-rise sigmoid' disappeared when the patients became recumbent and the colonic air redistributed. (author)

  4. Motion tracking in narrow spaces: a structured light approach

    DEFF Research Database (Denmark)

    Olesen, Oline Vinter; Paulsen, Rasmus; Højgaard, Liselotte

    2010-01-01

    point clouds are matched to a reference surface using a robust iterative closest point algorithm. A main challenge is the narrow geometry requiring a compact structured light system and an oblique angle of observation. The system is validated using a mannequin head mounted on a rotary stage. We compare...

  5. Free-Molecular Gas Flow in Narrow (Nanoscale) Channel

    Czech Academy of Sciences Publication Activity Database

    Levdansky, V.V.; Roldugin, V.I.; Žďanov, V.M.; Ždímal, Vladimír

    2014-01-01

    Roč. 87, č. 4 (2014), s. 802-814 ISSN 1062-0125 Grant - others:BRFFI(BY) T12P-018; RFBR(RU) 12-08-90009 Institutional support: RVO:67985858 Keywords : narrow channels * free-molecular gas flow * surface diffusion Subject RIV: CF - Physical ; Theoretical Chemistry

  6. Narrow-band filters for the lightning imager

    Science.gov (United States)

    Piegari, Angela; Di Sarcina, Ilaria; Grilli, Maria Luisa; Menchini, Francesca; Scaglione, Salvatore; Sytchkova, Anna; Zola, Danilo; Cuevas, Leticia P.

    2017-11-01

    The study of lightning phenomena will be carried out by a dedicated instrument, the lightning imager, that will make use of narrow-band transmission filters for separating the Oxygen emission lines in the clouds, from the background signal. The design, manufacturing and testing of these optical filters will be described here.

  7. Moving beyond Idealistically Narrow Discourses in Citizenship Education

    Science.gov (United States)

    Fischman, Gustavo E.; Haas, Eric

    2014-01-01

    The main goal of this article is to provide conceptual guidelines to move the pedagogical debate in the field of citizenship education beyond idealistically narrow models. We begin by providing an overview of key shortcomings presented in most citizenship education programs, specifically in the United States of America. The second section presents…

  8. Age and growth of narrow-barred Spanish mackerel ...

    African Journals Online (AJOL)

    The narrow-barred Spanish mackerel Scomberomorus commerson is one of the most important linefish species caught in KwaZulu-Natal and southern Mozambique waters, forming the basis of important commercial, artisanal and recreational fisheries. A total of 439 S. commerson were sampled along the east coast of ...

  9. Learning English Vocabulary by Hyperglossing and Narrow Reading: Readlang

    Science.gov (United States)

    Kiliçkaya, Ferit

    2017-01-01

    Hyperglossing -textual and/or pictorial representations of lexical items is found to be aiding the development of decoding, and narrow reading is a useful strategy for L2 reading pedagogy. Although the research on glossing provides mixed findings regarding the benefits, it is also acknowledged that glossing improves especially incidental…

  10. Modeling of air flow through a narrow crack

    International Nuclear Information System (INIS)

    Trojek, T.; Cechak, T.; Moucka, L.; Fronka, A.

    2004-01-01

    Radon transport in dwellings is governed to a significant extent by pressure differences and properties of transport pathways. A model of air flow through narrow cracks was created in order to facilitate prediction of air velocity and air flow. Theoretical calculations, based on numerical solution of a system of differential equations, were compared with measurements carried out on a window crack. (P.A.)

  11. Solar neutrinos

    International Nuclear Information System (INIS)

    Schatzman, E.

    1983-01-01

    The solar energy is produced by a series of nuclear reactions taking place in the deep interior of the sun. Some of these reactions produce neutrinos which may be detected, the proper detection system being available. The results of the Davis experiment (with 37 Cl) are given, showing a deficiency in the solar neutrino flux. The relevant explanation is either a property of the neutrino or an important change in the physics of the solar models. The prospect of a new experiment (with 71 Ga) is important as it will decide which of the two explanations is correct [fr

  12. Galaxy properties from J-PAS narrow-band photometry

    Science.gov (United States)

    Mejía-Narváez, A.; Bruzual, G.; Magris, C. G.; Alcaniz, J. S.; Benítez, N.; Carneiro, S.; Cenarro, A. J.; Cristóbal-Hornillos, D.; Dupke, R.; Ederoclite, A.; Marín-Franch, A.; de Oliveira, C. Mendes; Moles, M.; Sodre, L.; Taylor, K.; Varela, J.; Ramió, H. Vázquez

    2017-11-01

    We study the consistency of the physical properties of galaxies retrieved from spectral energy distribution (SED) fitting as a function of spectral resolution and signal-to-noise ratio (SNR). Using a selection of physically motivated star formation histories, we set up a control sample of mock galaxy spectra representing observations of the local Universe in high-resolution spectroscopy, and in 56 narrow-band and 5 broad-band photometry. We fit the SEDs at these spectral resolutions and compute their corresponding stellar mass, the mass- and luminosity-weighted age and metallicity, and the dust extinction. We study the biases, correlations and degeneracies affecting the retrieved parameters and explore the role of the spectral resolution and the SNR in regulating these degeneracies. We find that narrow-band photometry and spectroscopy yield similar trends in the physical properties derived, the former being considerably more precise. Using a galaxy sample from the Sloan Digital Sky Survey (SDSS), we compare more realistically the results obtained from high-resolution and narrow-band SEDs (synthesized from the same SDSS spectra) following the same spectral fitting procedures. We use results from the literature as a benchmark to our spectroscopic estimates and show that the prior probability distribution functions, commonly adopted in parametric methods, may introduce biases not accounted for in a Bayesian framework. We conclude that narrow-band photometry yields the same trend in the age-metallicity relation in the literature, provided it is affected by the same biases as spectroscopy, albeit the precision achieved with the latter is generally twice as large as with the narrow-band, at SNR values typical of the different kinds of data.

  13. Long-term north-south asymmetry in solar wind speed inferred from geomagnetic activity: A new type of century-scale solar oscillation?

    DEFF Research Database (Denmark)

    Mursula, K.; Zieger, B.

    2001-01-01

    A significant and very similar annual variation in solar wind speed and in geomagnetic activity was recently found around all the four solar cycle minima covered by direct SW observations since mid-1960's. We have shown that the phase of this annual variation reverses with the Sun's polarity...... reversal, depicting a new form of 22-year periodicity. The annual variation results from a small north-south asymmetry in SW speed distribution where the minimum speed region is shifted toward the northern magnetic hemisphere. Here we study the very long-term evolution of the annual variation using early...... registrations of geomagnetic activity. We find a significant annual variation during the high-activity solar cycles in mid-19th century and since 1930's. Most interestingly, the SW speed asymmetry in mid-19th century was opposite to the present asymmetry, i.e., the minimum speed region was then shifted toward...

  14. Solar chulha

    Science.gov (United States)

    Jadhao, P. H.; Patrikar, S. R.

    2016-05-01

    The main goal of the proposed system is to transfer energy from sun to the cooking load that is located in the kitchen. The energy is first collected by the solar collector lens system and two curve bars of same radius of curvature are mounted parallel and adjacent to each other at different height the solar collector is clamed on this two bars such that solar collector is exactly perpendicular to sunlight. The topology includes an additional feature which is window in the wall through which the beam is collimated is directed in the of kitchen. The solar energy that is collected is directed by the mirror system into the kitchen, where it is redirected to cooking platform located in the kitchen. The special feature in this system full Indian meal can be made since cooking platform is indoors.

  15. Solar prominences

    CERN Document Server

    Engvold, Oddbjørn

    2015-01-01

    This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

  16. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  17. Solar chulha

    Energy Technology Data Exchange (ETDEWEB)

    Jadhao, P. H. [Department of Physics J.D. Institute of Engg. & Tech. Yavatmal (India); Patrikar, S. R. [Department of Physics VNIT, Nagpur (India)

    2016-05-06

    The main goal of the proposed system is to transfer energy from sun to the cooking load that is located in the kitchen. The energy is first collected by the solar collector lens system and two curve bars of same radius of curvature are mounted parallel and adjacent to each other at different height the solar collector is clamed on this two bars such that solar collector is exactly perpendicular to sunlight. The topology includes an additional feature which is window in the wall through which the beam is collimated is directed in the of kitchen. The solar energy that is collected is directed by the mirror system into the kitchen, where it is redirected to cooking platform located in the kitchen. The special feature in this system full Indian meal can be made since cooking platform is indoors.

  18. Solar Neutrinos

    OpenAIRE

    Pallavicini, Marco

    2009-01-01

    The status of solar neutrino experiments and their implications for both nonstandard astrophysics ({\\it e.g.,} cool sun models) and nonstandard neutrino properties ({\\it e.g.,} MSW conversions) are discussed. Assuming that all of the experiments are correct, the relative rates observed by Kamiokande and Homestake are hard to account for by a purely astrophysical solution, while MSW conversions can describe all of the data. Assuming the standard solar model, there are two allowed regions for M...

  19. Solar generation

    International Nuclear Information System (INIS)

    Villeneuve, J.

    2012-01-01

    Solar energy might become the main energy resource for mankind in the next 50 years. The author describes the assets of photovoltaic energy and helio-thermodynamics and reviews the conditions required for such a future. The first condition is an integrated approach for the development of solar energy in buildings, it means to develop in parallel the use of low-power appliances, to insulate buildings, to use daylight. Secondly to find an efficient solution to store solar energy. In the building sector this solution could be the use of solar energy (through solar panels) and geothermal heat pump to be able to recover in winter the calories caught in summer and stored in the ground. In a warmer and warmer world, the production of cold from solar calories has the advantage of sparing electricity and to make the demand for calories corresponding with the peak of the resource. A graph shows that the expected cost of photovoltaic electricity in 2020 will be half the 2011 cost and will correspond to the retail price of electricity. (A.C.)

  20. 75 FR 11908 - Narrow Woven Ribbons With Woven Selvedge From China and Taiwan

    Science.gov (United States)

    2010-03-12

    ...)] Narrow Woven Ribbons With Woven Selvedge From China and Taiwan AGENCY: United States International Trade... less- than-fair-value imports from Taiwan of narrow woven ribbons with woven selvedge (``narrow woven... merchandise as ``* * * narrow woven ribbons with woven selvedge, in any length, but with a width (measured at...

  1. Solar Spectral Irradiance Variations in 240 - 1600 nm During the Recent Solar Cycles 21 - 23

    Science.gov (United States)

    Pagaran, J.; Weber, M.; Deland, M. T.; Floyd, L. E.; Burrows, J. P.

    2011-08-01

    Regular solar spectral irradiance (SSI) observations from space that simultaneously cover the UV, visible (vis), and the near-IR (NIR) spectral region began with SCIAMACHY aboard ENVISAT in August 2002. Up to now, these direct observations cover less than a decade. In order for these SSI measurements to be useful in assessing the role of the Sun in climate change, records covering more than an eleven-year solar cycle are required. By using our recently developed empirical SCIA proxy model, we reconstruct daily SSI values over several decades by using solar proxies scaled to short-term SCIAMACHY solar irradiance observations to describe decadal irradiance changes. These calculations are compared to existing solar data: the UV data from SUSIM/UARS, from the DeLand & Cebula satellite composite, and the SIP model (S2K+VUV2002); and UV-vis-IR data from the NRLSSI and SATIRE models, and SIM/SORCE measurements. The mean SSI of the latter models show good agreement (less than 5%) in the vis regions over three decades while larger disagreements (10 - 20%) are found in the UV and IR regions. Between minima and maxima of Solar Cycles 21, 22, and 23, the inferred SSI variability from the SCIA proxy is intermediate between SATIRE and NRLSSI in the UV. While the DeLand & Cebula composite provide the highest variability between solar minimum and maximum, the SIP/Solar2000 and NRLSSI models show minimum variability, which may be due to the use of a single proxy in the modeling of the irradiances. In the vis-IR spectral region, the SCIA proxy model reports lower values in the changes from solar maximum to minimum, which may be attributed to overestimations of the sunspot proxy used in modeling the SCIAMACHY irradiances. The fairly short timeseries of SIM/SORCE shows a steeper decreasing (increasing) trend in the UV (vis) than the other data during the descending phase of Solar Cycle 23. Though considered to be only provisional, the opposite trend seen in the visible SIM data

  2. Solar Features - Solar Flares - SIDS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Sudden Ionospheric Disturbance (SID) is any of several radio propagation anomalies due to ionospheric changes resulting from solar or geophysical events.

  3. Solar Features - Solar Flares - Patrol

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  4. A Novel Hybrid Statistical Particle Swarm Optimization for Multimodal Functions and Frequency Control of Hybrid Wind-Solar System

    Science.gov (United States)

    Verma, Harish Kumar; Jain, Cheshta

    2016-09-01

    In this article, a hybrid algorithm of particle swarm optimization (PSO) with statistical parameter (HSPSO) is proposed. Basic PSO for shifted multimodal problems have low searching precision due to falling into a number of local minima. The proposed approach uses statistical characteristics to update the velocity of the particle to avoid local minima and help particles to search global optimum with improved convergence. The performance of the newly developed algorithm is verified using various standard multimodal, multivariable, shifted hybrid composition benchmark problems. Further, the comparative analysis of HSPSO with variants of PSO is tested to control frequency of hybrid renewable energy system which comprises solar system, wind system, diesel generator, aqua electrolyzer and ultra capacitor. A significant improvement in convergence characteristic of HSPSO algorithm over other variants of PSO is observed in solving benchmark optimization and renewable hybrid system problems.

  5. Coulomb and nuclear excitations of narrow resonances in 17Ne

    Directory of Open Access Journals (Sweden)

    J. Marganiec

    2016-08-01

    Full Text Available New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

  6. Period effects, cohort effects, and the narrowing gender wage gap.

    Science.gov (United States)

    Campbell, Colin; Pearlman, Jessica

    2013-11-01

    Despite the abundance of sociological research on the gender wage gap, questions remain. In particular, the role of cohorts is under investigated. Using data from the Current Population Survey, we use age-period-cohort analysis to uniquely estimate age, period, and cohort effects on the gender wage gap. The narrowing of the gender wage gap that occurred between 1975 and 2009 is largely due to cohort effects. Since the mid-1990s, the gender wage gap has continued to close absent of period effects. While gains in female wages contributed to declines in the gender wage gap for cohorts born before 1950, for later cohorts the narrowing of the gender wage gap is primarily a result of declines in male wages. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. All-fiber noninterferometric narrow-transmission-bandpass filter.

    Science.gov (United States)

    Sáez-Rodríguez, D; Cruz, J L; Díez, A; Andrés, M V

    2012-10-15

    In-fiber mode engineering based on the combination of Bragg and long-period gratings (LPGs) permits the implementation of noninterferometric transmission filters with narrow passbands using standard single-mode fiber. The design of the bandpass filter is based on the coupling between propagating and counterpropagating cladding modes in two fiber Bragg gratings. A LPG located between the Bragg gratings transfers power from the input fundamental mode to a specific cladding mode and recouples the filtered signal to the output fundamental mode. The filter produces a series of narrow passbands of about 30 pm linewidth with a maximum transmittance above 60%, 20 dB isolation, and passband separation of about 1 nm, each corresponding to the contribution of a different cladding mode.

  8. Cervical spinal canal narrowing and cervical neurologi-cal injuries

    Directory of Open Access Journals (Sweden)

    ZHANG Ling

    2012-04-01

    Full Text Available 【Abstract】Cervical spinal canal narrowing can lead to injury of the spinal cord and neurological symptoms in-cluding neck pain, headache, weakness and parasthesisas. According to previous and recent clinical researches, we investigated the geometric parameters of normal cervical spinal canal including the sagittal and transverse diameters as well as Torg ratio. The mean sagittal diameter of cervical spinal canal at C 1 to C 7 ranges from 15.33 mm to 20.46 mm, the mean transverse diameter at the same levels ranges from 24.45 mm to 27.00 mm and the mean value of Torg ratio is 0.96. With respect to narrow cervical spinal canal, the following charaterstics are found: firstly, extension of the cervical spine results in statistically significant stenosis as compared with the flexed or neutral positions; secondly, females sustain cervical spinal canal narrowing more easily than males; finally, the consistent narrowest cervical canal level is at C 4 for all ethnicity, but there is a slight variation in the sagittal diameter of cervical spinal stenosis (≤14 mm in Whites, ≤ 12 mm in Japanese, ≤13.7 mm in Chinese. Narrow sagittal cervical canal diameter brings about an increased risk of neurological injuries in traumatic, degenerative and inflam-matory conditions and is related with extension of cervical spine, gender, as well as ethnicity. It is hoped that this re-view will be helpful in diagnosing spinal cord and neuro-logical injuries with the geometric parameters of cervical spine in the future. Key words: Spinal cord injuries; Spinal stenosis; Trauma, nervous system

  9. The Argument for a Narrow Conception of 'Religious Autonomy'

    DEFF Research Database (Denmark)

    Christoffersen, Lisbet

    2015-01-01

    This article argues for a both horizontal and vertical narrow concept of collective freedom of Religion. The most recent ECtHR judgments as well as the US Supreme Court Hosanna-Tabor case leads theory to establish religious autonomy based on parallel legal roders. Nordic theory has been based on ...... on lack of acknowledgement of Canon Law, which is no longer possible. A future path might be to accept overlapping normative orders, however with secular courts as the final institutions....

  10. Narrow line profiles and interacting gas flows in active galaxies

    International Nuclear Information System (INIS)

    Mardaljevic, J.; Raine, D.J.; Smith, M.D.

    1986-01-01

    The 'catapult model' of the narrow line region involves both infalling and outflowing clouds interacting with an outflowing wind. The emission line profiles in this model are derived and the results compared with observation. Supersonic and subsonic winds in the interaction zone produce distinct line profiles, both of which are observed. Flat-topped profiles, the presence of broad wings, asymmetry and line shifts are discussed. A relationship between profile shape and X-ray properties is predicted. (author)

  11. Elongational viscosity of narrow molar mass distribution polystyrene

    DEFF Research Database (Denmark)

    Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...... above the linear viscoelastic prediction at intermediate strains, indicating strain hardening. The steady elongational viscosities are monotone decreasing functions of elongation rate. At elongation rates larger than the inverse reptation time, the steady elongational viscosity scales linearly...

  12. Ultrahigh-efficiency, very narrow-passband, tunable optical filter

    Science.gov (United States)

    Sandford, Stephen P.; Thomas, Milfred E.

    1994-01-01

    Recently developed technologies have been uniquely integrated to produce optical filters with unprecedented performance. The precise design and fabrication of narrow-passband and high-efficiency optical filters with a central frequency of 532 nm are reported. Measurements with these filters demonstrate a performance that accurately mirrors the design specification, with one filter having a passband of 70 pm and an efficiency greater than 90% and the second filter having a passband of 7 pm and an efficiency greater than 80%.

  13. Low-frequency oscillations in narrow vibrated granular systems

    OpenAIRE

    Rivas, Nicolas; Luding, Stefan; Thornton, Anthony R

    2013-01-01

    We present simulations and a theoretical treatment of vertically vibrated granular media. The systems considered are confined in narrow quasi-two-dimensional and quasi-one-dimensional (column) geometries, where the vertical extension of the container is much larger than both horizontal lengths. The additional geometric constraint present in the column setup frustrates the convection state that is normally observed in wider geometries. This makes it possible to study collective oscillations of...

  14. Gain-switched all-fiber laser with narrow bandwidth

    DEFF Research Database (Denmark)

    Larsen, Casper; Giesberts, M.; Nyga, S.

    2013-01-01

    Gain-switching of a CW fiber laser is a simple and cost-effective approach to generate pulses using an all-fiber system. We report on the construction of a narrow bandwidth (below 0.1 nm) gain-switched fiber laser and optimize the pulse energy and pulse duration under this constraint. The extracted...... the bandwidth below 0.1 nm. This allows frequency doubling in a periodically poled lithium tantalate crystal with a reasonable conversion efficiency....

  15. Photoluminescence from narrow InAs-AlSb quantum wells

    Science.gov (United States)

    Brar, Berinder; Kroemer, Herbert; Ibbetson, James; English, John H.

    1993-01-01

    We report on photoluminescence spectra from narrow InAs-AlSb quantum wells. Strong, clearly resolved peaks for well widths from 2 to 8 monolayers were observed. Transmission electron micrographs show direct evidence for the structural quality of the quantum well structures. The transition energies of the narrowest wells suggest a strong influence of the AlSb X-barrier on the electronic states in the conduction band.

  16. Electron correlations in narrow energy bands: modified polar model approach

    Directory of Open Access Journals (Sweden)

    L. Didukh

    2008-09-01

    Full Text Available The electron correlations in narrow energy bands are examined within the framework of the modified form of polar model. This model permits to analyze the effect of strong Coulomb correlation, inter-atomic exchange and correlated hopping of electrons and explain some peculiarities of the properties of narrow-band materials, namely the metal-insulator transition with an increase of temperature, nonlinear concentration dependence of Curie temperature and peculiarities of transport properties of electronic subsystem. Using a variant of generalized Hartree-Fock approximation, the single-electron Green's function and quasi-particle energy spectrum of the model are calculated. Metal-insulator transition with the change of temperature is investigated in a system with correlated hopping. Processes of ferromagnetic ordering stabilization in the system with various forms of electronic DOS are studied. The static conductivity and effective spin-dependent masses of current carriers are calculated as a function of electron concentration at various DOS forms. The correlated hopping is shown to cause the electron-hole asymmetry of transport and ferromagnetic properties of narrow band materials.

  17. Modelling and Simulations of a Narrow Track Tilting Vehicle

    Directory of Open Access Journals (Sweden)

    JJ Chong

    2016-10-01

    Full Text Available Narrow track tilting vehicle is a new category of vehicle that combines the dynamical abilities of a passenger car with a motorcycle. In the presence of overturning moments during cornering, an accurate assessment of the lateral dynamics plays an important role to improve their stability and handling. In order to stabilise or control the narrow tilting vehicle, the demand tilt angle can be calculated from the vehicle’s lateral acceleration and controlled by either steering input of the vehicle or using additional titling actuator to reach this desired angle. The aim of this article is to present a new approach for developing the lateral dynamics model of a narrow track tilting vehicle. First, this approach utilises the well-known geometry ‘bicycle model’ and parameter estimation methods. Second, by using a tuning method, the unknown and uncertainties are taken into account and regulated through an optimisation procedure to minimise the model biases in order to improve the modelling accuracy. Therefore, the optimised model can be used as a platform to develop the vehicle control strategy. Numerical simulations have been performed in a comparison with the experimental data to validate the model accuracy.

  18. Why Ξ (1690 ) and Ξ (2120 ) are so narrow

    Science.gov (United States)

    Khemchandani, K. P.; Martínez Torres, A.; Hosaka, A.; Nagahiro, H.; Navarra, F. S.; Nielsen, M.

    2018-02-01

    The Ξ baryons are expected to be naturally narrower as compared to their nonstrange and strange counterparts since they have only one light quark and, thus, their decay involves producing either a light meson and doubly strange baryon or both meson and baryon with strangeness which involves, relatively, more energy. In fact, some Ξ 's have full widths of the order of even 10-20 MeV when, in principle, they have a large phase space to decay to some open channels. Such is the case of Ξ (1690 ), for which the width has been found to be of the order of 10 MeV in the latest BABAR and BELLE data. In this manuscript we study why some Ξ 's are so narrow. Based on a coupled channel calculation of the pseudoscalar meson-baryon and vector meson-baryon systems with chiral and hidden local symmetry Lagrangians, we find that the answer lies in the intricate hadron dynamics. We find that the known mass, width, spin-parity, and branching ratios of Ξ (1690 ) can be naturally explained in terms of coupled channel meson-baryon dynamics. We find another narrow resonance which can be related to Ξ (2120 ). We also look for exotic states Ξ+ and Ξ- but find none. In addition we provide the cross sections for K ¯Λ ,K ¯Σ →π Ξ which can be useful for understanding the enhanced yield of Ξ reported in recent studies of heavy ion collisions.

  19. Searching for Variability of NV Intrinsic Narrow Absorption Line Systems

    Science.gov (United States)

    Rodruck, Michael; Charlton, Jane; Ganguly, Rajib

    2018-01-01

    The majority of quasar absorption line systems with NV detected are found within the associated region (within 5000 km/s of the quasar redshift) and many/most are believed to be related to the quasar accretion disk wind or outflows. The most definite evidence that these NV absorbers are "intrinsic" is partial covering of the quasar continuum source and/or broad line region. Over 75 quasars containing NV narrow absorption lines have observations obtained at different times with the Keck/HIRES and the VLT/UVES spectrographs at high resolution. The interval between these observations range from months to a decade in the quasar rest frame. While variability is common for intrinsic broad and mini-broad absorption lines, intrinsic narrow absorption lines have been found to be less likely to vary, though systematic studies with large, high quality datasets have been limited. The variability timescales are useful for deriving gas densities and thus the distances from the central engines. This is important in mapping the quasar surroundings, understanding the accretion disk wind mechanism, and assessing the effect the wind has on the galaxy surroundings. We report on the results of a systematic study of variability of NV NALs, exploiting the overlap of targets for observations in the archives of Keck and VLT, and discuss the consequences for interpretation of the origin of intrinsic narrow absorption lines.

  20. Laser linewidth narrowing using transient spectral hole burning

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, Charles W.; Cone, Rufus L. [Department of Physics, Montana State University, Bozeman, MT 59715 (United States); Böttger, Thomas, E-mail: tbottger@usfca.edu [Department of Physics and Astronomy, 2130 Fulton Street, University of San Francisco, San Francisco, CA 94117 (United States)

    2014-08-01

    We demonstrate significant narrowing of laser linewidths by high optical density materials with inhomogeneously broadened absorption. As a laser propagates through the material, the nonlinear spectral hole burning process causes a progressive self-filtering of the laser spectrum, potentially reaching values less than the homogeneous linewidth. The transient spectral hole dynamically adjusts itself to the instantaneous frequency of the laser, passively suppressing laser phase noise and side modes over the entire material absorption bandwidth without the need for electronic or optical feedback to the laser. Wide bandwidth laser phase noise suppression was demonstrated using Er{sup 3+} doped Y{sub 2}SiO{sub 5} and LiNbO{sub 3} at 1.5 μm by employing time-delayed self-heterodyne detection of an external cavity diode laser to study the spectral narrowing effect. Our method is not restricted to any particular wavelength or laser system and is attractive for a range of applications where ultra-low phase noise sources are required. - Highlights: • We demonstrate significant laser linewidths narrowing by high optical density materials. • Nonlinear spectral hole burning causes progressive self-filtering of laser spectrum. • Filter dynamically adjusts itself to the instantaneous frequency of the laser. • Demonstrated at 1.5 μm in Er{sup 3+} doped Y{sub 2}SiO{sub 5} and LiNbO{sub 3}. • Linewidth filtering is not restricted to any particular wavelength or laser system.

  1. Joint Space Narrowing in Patients With Pisotriquetral Osteoarthritis.

    Science.gov (United States)

    Ten Berg, Paul W L; Heeg, Erik; Strackee, Simon D; Streekstra, Geert J

    2017-09-01

    Patients with suspected pisotriquetral osteoarthritis may show joint space narrowing. However, the extent of joint space narrowing and its deviation from the joint space width (JSW) in normal anatomy is unknown. In this pathoanatomic study, we therefore compared the JSW in the pisotriquetral joint between osteoarthritic patient wrists and healthy wrists. We reviewed preoperative computed tomography (CT) scans of 8 wrists of patients with ulnar-sided wrist pain who underwent a pisiformectomy with confirmed pisotriquetral osteoarthritis at surgery. We also reviewed CT scans of 20 normal wrists from healthy volunteers serving as control group. Three-dimensional CT models of the pisiform and triquetrum were obtained from both affected and normal wrists, after which the minimum JSW was calculated in an automated fashion. In the patient group, the median (interquartile range) of the minimum JSW was 0.1 mm (0.0-0.2), and in the control group, 0.8 mm (0.3-0.9) ( P = .007). We showed that the pisotriquetral joint space in osteoarthritic patient wrists was significantly narrowed compared with healthy wrists. These results suggest that JSW evaluation has a potential diagnostic value in the work-up of patients with suspected pisotriquetral osteoarthritis. This is an interesting area for future clinical research, especially because no gold standard for diagnosing pisotriquetral osteoarthritis has been established yet.

  2. Minima de L'intégrale D'action du Problème Newtoniende 4 Corps de Masses Égales Dans R3: Orbites `Hip-Hop'

    Science.gov (United States)

    Chenciner, Alain; Venturelli, Andrea

    2000-09-01

    We consider the problem of 4 bodies of equal masses in R 3 for the Newtonian r-1 potential. We address the question of the absolute minima of the action integral among (anti)symmetric loops of class H 1 whose period is fixed. It is the simplest case for which the results of [4] (corrected in [5]) do not apply: the minima cannot be the relative equilibria whose configuration is an absolute minimum of the potential among the configurations having a given moment of inertia with respect to their center of mass. This is because the regular tetrahedron cannot have a relative equilibrium motion in R 3 (see [2]). We show that the absolute minima of the action are not homographic motions. We also show that if we force the configuration to admit a certain type of symmetry of order 4, the absolute minimum is a collisionless orbit whose configuration ‘hesitates’ between the central configuration of the square and the one of the tetrahedron. We call these orbits ‘hip-hop’. A similar result holds in case of a symmetry of order 3 where the central configuration of the equilateral triangle with a body at the center of mass replaces the square.

  3. Harmonic model for solar and climate cyclical variation throughout the Holocene based on Jupiter-Saturn tidal frequencies plus the 11-year solar dynamo cycle

    Science.gov (United States)

    Scafetta, N.

    2012-12-01

    We show that the Schwabe frequency band of the Zurich sunspot record since 1749 is made of three major cycles that are closely related to the spring tidal period of Jupiter and Saturn (~9.93 year), to the tidal sidereal period of Jupiter (about 11.86 years) and to a central cycle that may be associated to a quasi-11-year solar dynamo cycle. The central harmonic is approximately synchronized to the average of the two planetary frequencies. A harmonic model based on the above two planetary tidal frequencies and on the exact dates of Jupiter and Saturn planetary tidal phases, plus a theoretically deduced 10.87-year central cycle reveals major beat periods occurring at about 115, 61 and 130 years, plus a quasi-millennial large beat cycle around 983 years. Equivalent synchronized cycles are found in cosmogenic solar proxy records used to reconstruct solar activity and in proxy climate records throughout the Holocene (last 12,000 years) up to now. The quasi-secular beat oscillations hindcast reasonably well the known prolonged periods of low solar activity during the last millennium such as the Oort, Wolf, Sporer, Maunder and Dalton minima, as well as the 17 115-year long oscillations found in a detailed temperature reconstruction of the Northern Hemisphere covering the last 2000 years. The millennial three-frequency beat cycle hindcasts equivalent solar and climate cycles for 12,000 years. Finally, the harmonic model herein proposed reconstructs the prolonged solar minima around 1900-1920 and 1960-1980, the secular solar maxima around 1870-1890, 1940-1950 and 1995-2005, and a secular upward trending during the 20th century. The latter modulated trending agrees well with some solar proxy model, with the ACRIM TSI satellite composite and with the global surface temperature modulation since 1850. The model forecasts a new prolonged solar minimum during 2020-2045, which is produced by the minima of both the 61 and 115-year reconstructed cycles. Finally, the model predicts

  4. [Correlation of the width of annual tree rings with climatic changes and solar activity].

    Science.gov (United States)

    Rozanov, M I; Prokudina, V S

    2002-01-01

    Fluctuations in the width of annual tree rings in the time interval from the eighth century till the present time were analyzed on the basis of dendroclimatic scales. Periods of extremely high and low growth of trees were distinguished, and their correlations with heliogeophysical factors were studied. The major climatic parameters determining the growth of trees are warmth and moisture; a small gain is observed in cold and droughty periods. No correlations between the width of tree rings and the minima and maxima of solar activity cycles were observed with the method used.

  5. Temporal Variations in Solar Irradiance Since 1947

    Science.gov (United States)

    Tebabal, A.; Damtie, B.; Nigussie, M.; Yizengaw, E.

    2017-08-01

    The study of variations in total solar irradiance (TSI) and spectral irradiance is important for understanding how the Sun affects the Earth's climate. A data-driven approach is used in this article to analyze and model the temporal variation of the TSI and Mg ii index back to 1947. In both cases, observed data in the time interval of the satellite era, 1978 - 2013, were used for neural network (NN) model-design and testing. For this particular purpose, the evolution of the solar magnetic field is assumed to be the main driver for the day-to-day irradiance variability. First, we design a model for the Mg ii index data from F10.7 cm solar radio-flux using the NN approach in the time span of 1978 through 2013. Results of Mg ii index model were tested using various numbers of hidden nodes. The predicted values of the hidden layer with five nodes correspond well to the composite Mg ii values. The model reproduces 94% of the variability in the composite Mg ii index, including the secular decline between the 1996 and 2008 solar cycle minima. Finally, the extrapolation of the Mg ii index was performed using the developed model from F10.7 cm back to 1947. Similarly, the NN model was designed for TSI variability study over the time span of the satellite era using data from the Physikalisch-Meteorologisches Observatorium Davos (PMOD) as a target, and solar activity indices as model inputs. This model was able to reproduce the daily irradiance variations with a correlation coefficient of 0.937 from sunspot and facular measurements in the time span of 1978 - 2013. Finally, the temporal variation of the TSI was analyzed using the designed NN model back to 1947 from the Photometric Sunspot Index (PSI) and the extrapolated Mg ii index. The extrapolated TSI result indicates that the amplitudes of Solar Cycles 19 and 21 are closely comparable to each other, and Solar Cycle 20 appears to be of lower irradiance during its maximum.

  6. Solar cells

    International Nuclear Information System (INIS)

    1980-01-01

    A method of producing solar cells is described which consists of producing a substantially monocrystalline tubular body of silicon or other suitable semiconductor material, treating this body to form an annular rectifying junction and then cutting it longitudinally to form a number of nearly flat ribbons from which the solar cells are fabricated. The P=N rectifying junction produced by the formation of silicon dioxide on the layers at the inner and outer surfaces of the body can be formed by ion-implantation or diffusion. (U.K.)

  7. A New Approach to Micro-arcsecond Astrometry with SIM Allowing Early Mission Narrow Angle Measurements of Compelling Astronomical Targets

    Science.gov (United States)

    Shaklan, Stuart; Pan, Xiaopei

    2004-01-01

    The Space Interferometry Mission (SIM) is capable of detecting and measuring the mass of terrestrial planets around stars other than our own. It can measure the mass of black holes and the visual orbits of radio and x-ray binary sources. SIM makes possible a new level of understanding of complex astrophysical processes. SIM achieves its high precision in the so-called narrow-angle regime. This is defined by a 1 degree diameter field in which the position of a target star is measured with respect to a set of reference stars. The observation is performed in two parts: first, SIM observes a grid of stars that spans the full sky. After a few years, repeated observations of the grid allow one to determine the orientation of the interferometer baseline. Second, throughout the mission, SIM periodically observes in the narrow-angle mode. Every narrow-angle observation is linked to the grid to determine the precise attitude and length of the baseline. The narrow angle process demands patience. It is not until five years after launch that SIM achieves its ultimate accuracy of 1 microarcsecond. The accuracy is degraded by a factor of approx. 2 at mid-mission. Our work proposes a technique for narrow angle astrometry that does not rely on the measurement of grid stars. This technique, called Gridless Narrow Angle Astrometry (GNAA) can obtain microarcsecond accuracy and can detect extra-solar planets and other exciting objects with a few days of observation. It can be applied as early as during the first six months of in-orbit calibration (IOC). The motivations for doing this are strong. First, and obviously, it is an insurance policy against a catastrophic mid-mission failure. Second, at the start of the mission, with several space-based interferometers in the planning or implementation phase, NASA will be eager to capture the public's imagination with interferometric science. Third, early results and a technique that can duplicate those results throughout the mission will

  8. Solar Energy and You.

    Science.gov (United States)

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    This booklet provides an introduction to solar energy by discussing: (1) how a home is heated; (2) how solar energy can help in the heating process; (3) the characteristics of passive solar houses; (4) the characteristics of active solar houses; (5) how solar heat is stored; and (6) other uses of solar energy. Also provided are 10 questions to…

  9. Multi-scale harmonic model for solar and climate cyclical variation throughout the Holocene based on Jupiter-Saturn tidal frequencies plus the 11-year solar dynamo cycle

    Science.gov (United States)

    Scafetta, Nicola

    2012-05-01

    The Schwabe frequency band of the Zurich sunspot record since 1749 is found to be made of three major cycles with periods of about 9.98, 10.9 and 11.86 years. The side frequencies appear to be closely related to the spring tidal period of Jupiter and Saturn (range between 9.5 and 10.5 years, and median 9.93 years) and to the tidal sidereal period of Jupiter (about 11.86 years). The central cycle may be associated to a quasi-11-year solar dynamo cycle that appears to be approximately synchronized to the average of the two planetary frequencies. A simplified harmonic constituent model based on the above two planetary tidal frequencies and on the exact dates of Jupiter and Saturn planetary tidal phases, plus a theoretically deduced 10.87-year central cycle reveals complex quasi-periodic interference/beat patterns. The major beat periods occur at about 115, 61 and 130 years, plus a quasi-millennial large beat cycle around 983 years. We show that equivalent synchronized cycles are found in cosmogenic records used to reconstruct solar activity and in proxy climate records throughout the Holocene (last 12,000 years) up to now. The quasi-secular beat oscillations hindcast reasonably well the known prolonged periods of low solar activity during the last millennium such as the Oort, Wolf, Spörer, Maunder and Dalton minima, as well as the 17 115-year long oscillations found in a detailed temperature reconstruction of the Northern Hemisphere covering the last 2000 years. The millennial three-frequency beat cycle hindcasts equivalent solar and climate cycles for 12,000 years. Finally, the harmonic model herein proposed reconstructs the prolonged solar minima that occurred during 1900-1920 and 1960-1980 and the secular solar maxima around 1870-1890, 1940-1950 and 1995-2005 and a secular upward trending during the 20th century: this modulated trending agrees well with some solar proxy model, with the ACRIM TSI satellite composite and with the global surface temperature

  10. Solar polar magnetic field dependency of geomagnetic activity semiannual variation indicated in the Aa index

    Science.gov (United States)

    Oh, Suyeon; Yi, Yu

    2018-01-01

    Three major hypotheses have been proposed to explain the well-known semiannual variation of geomagnetic activity, maxima at equinoxes and minima at solstices. This study examined whether the seasonal variation of equinoctial geomagnetic activity is different in periods of opposite solar magnetic polarity in order to understand the contribution of the interplanetary magnetic field (IMF) in the Sun-Earth connection. Solar magnetic polarity is parallel to the Earth's polarity in solar minimum years of odd/even cycles but antiparallel in solar minimum years of even/odd cycles. The daily mean of the aa, Aa indices during each solar minimum was compared for periods when the solar magnetic polarity remained in opposite dipole conditions. The Aa index values were used for each of the three years surrounding the solar minimum years of the 14 solar cycles recorded since 1856. The Aa index reflects seasonal variation in geomagnetic activity, which is greater at the equinoxes than at the solstices. The Aa index reveals solar magnetic polarity dependency in which the geomagnetic activity is stronger in the antiparallel solar magnetic polarity condition than in the parallel one. The periodicity in semiannual variation of the Aa index is stronger in the antiparallel solar polar magnetic field period than in the parallel period. Additionally, we suggest the favorable IMF condition of the semiannual variation in geomagnetic activity. The orientation of IMF toward the Sun in spring and away from the Sun in fall mainly contributes to the semiannual variation of geomagnetic activity in both antiparallel and parallel solar minimum years.

  11. Theta Brain Rhythms Index Perceptual Narrowing in Infant Speech Perception

    Directory of Open Access Journals (Sweden)

    Alexis eBosseler

    2013-10-01

    Full Text Available The development of speech perception shows a dramatic transition between infancy and adulthood. Between 6 and 12 months, infants’ initial ability to discriminate all phonetic units across the worlds’ languages narrows—native discrimination increases while nonnative discrimination shows a steep decline. We used magnetoencephalography (MEG to examine whether brain oscillations in the theta band (4-8Hz, reflecting increases in attention and cognitive effort, would provide a neural measure of the perceptual narrowing phenomenon in speech. Using an oddball paradigm, we varied speech stimuli in two dimensions, stimulus frequency (frequent vs. infrequent and language (native vs. nonnative speech syllables and tested 6-month-old infants, 12-month-old infants, and adults. We hypothesized that 6-month-old infants would show increased relative theta power (RTP for frequent syllables, regardless of their status as native or nonnative syllables, reflecting young infants’ attention and cognitive effort in response to highly frequent stimuli (statistical learning. In adults, we hypothesized increased RTP for nonnative stimuli, regardless of their presentation frequency, reflecting increased cognitive effort for nonnative phonetic categories. The 12-month-old infants were expected to show a pattern in transition, but one more similar to adults than to 6-month-old infants. The MEG brain rhythm results supported these hypotheses. We suggest that perceptual narrowing in speech perception is governed by an implicit learning process. This learning process involves an implicit shift in attention from frequent events (infants to learned categories (adults. Theta brain oscillatory activity may provide an index of perceptual narrowing beyond speech, and would offer a test of whether the early speech learning process is governed by domain-general or domain-specific processes.

  12. Nasal base narrowing: the combined alar base excision technique.

    Science.gov (United States)

    Foda, Hossam M T

    2007-01-01

    To evaluate the role of the combined alar base excision technique in narrowing the nasal base and correcting excessive alar flare. The study included 60 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined an external alar wedge resection with an internal vestibular floor excision. All cases were followed up for a mean of 32 (range, 12-144) months. Nasal tip modification and correction of any preexisting caudal septal deformities were always completed before the nasal base narrowing. The mean width of the external alar wedge excised was 7.2 (range, 4-11) mm, whereas the mean width of the sill excision was 3.1 (range, 2-7) mm. Completing the internal excision first resulted in a more conservative external resection, thus avoiding any blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid formation were encountered, and the external alar wedge excision healed with an inconspicuous scar that was well hidden in the depth of the alar-facial crease. Finally, the risk of notching of the alar rim, which can occur at the junction of the external and internal excisions, was significantly reduced by adopting a 2-layered closure of the vestibular floor (P = .01). The combined alar base excision resulted in effective narrowing of the nasal base with elimination of excessive alar flare. Commonly feared complications, such as blunting of the alar-facial crease or notching of the alar rim, were avoided by using simple modifications in the technique of excision and closure.

  13. Solar system

    CERN Document Server

    Bell, Samantha

    2018-01-01

    "Using the new Next Generation Science Standards (NGSS), the My World of Science series provides the earliest readers with background on key STEM concepts. Solar System explores basic planetary astronomy in a simple, engaging way that will help readers develop word recognition and reading skills. Includes a glossary and index."-- Provided by publisher.

  14. Solar Neutrinos

    OpenAIRE

    Bellini, G.; Ianni, A.; Ranucci, G.

    2010-01-01

    Solar neutrino investigation has represented one of the most active field of particle physics over the past decade, accumulating important and sometimes unexpected achievements. After reviewing some of the most recent impressive successes, the future perspectives of this exciting area of neutrino research will be discussed.

  15. Solar Neutrinos

    Indian Academy of Sciences (India)

    Solar Neutrinos. Revathi Ananthakrishnan. 1. Introduction. The neutrino, which means the little neutral one in Ital- ian, is a very special elementary particle. It is a spin half, chargeless and almost . massless particle and therefore eluded detection for a long time. However, the sun is a rich source of neutrinos and physicists ...

  16. Solar Power

    Science.gov (United States)

    Ford, Norman C.; Kane, Joseph W.

    1971-01-01

    Proposes a method of collecting solar energy by using available plastics for Fresnel lenses to focus heat onto a converter where thermal dissociation of water would produce hydrogen. The hydrogen would be used as an efficient non-polluting fuel. Cost estimates are included. (AL)

  17. Period Effects, Cohort Effects, and the Narrowing Gender Wage Gap

    OpenAIRE

    Campbell, Colin; Pearlman, Jessica

    2013-01-01

    Despite the abundance of sociological research on the gender wage gap, questions remain. In particular, the role of cohorts is under investigated. Using data from the Current Population Survey, we use Age-Period-Cohort analysis to uniquely estimate age, period, and cohort effects on the gender wage gap. The narrowing of the gender wage gap that occurred between 1975 and 2009 is largely due to cohort effects. Since the mid-1990s, the gender wage gap has continued to close absent of period effe...

  18. Narrow beam dosimetry for high-energy hadrons and electrons

    CERN Document Server

    Pelliccioni, M; Ulrici, Luisa

    2001-01-01

    Organ doses and effective dose were calculated with the latest version of the Monte Carlo transport code FLUKA in the case of an anthropomorphic mathematical model exposed to monoenergetic narrow beams of protons, pions and electrons in the energy range 10°— 400 GeV. The target organs considered were right eye, thyroid, thymus, lung and breast. Simple scaling laws to the calculated values are given. The present data and formula should prove useful for dosimetric estimations in case of accidental exposures to high-energy beams.

  19. New narrow baryon resonances in pp inelastic scattering

    International Nuclear Information System (INIS)

    Tatischeff, B.; Willis, N.; Comets, M.P.; Courtat, P.; Gacougnolle, R.; Le Bornec, Y.; Loireleux, E.; Reide, F.; Yonnet, J.; Boivin, M.

    1999-01-01

    The reaction pp → pπ + X has been studied at 3 energies (T p 1520, 1805 and 2100 MeV) and 6 angles from 0 angle up to 17 angle (lab.). Several narrow states have been observed in missing mass spectra at: 1004, 1044, 1094 MeV. Their widths are typically one order of magnitude smaller than the widths of N * of Δ. Possible biases are discussed. These masses are in agreement with those calculated within a simple phenomenological mass formula based on color magnetic interaction between two colored quark clusters. (authors)

  20. Spectral narrowing of a 980 nm tapered diode laser bar

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Lucas Leclin, Gaëlle

    2011-01-01

    in wavelength specific applications and hence, it is vital to stabilize the emission spectrum of these devices. In our experiment, we describe the wavelength narrowing of a 12 element 980 nm tapered diode laser bar using a simple Littman configuration. The tapered laser bar which suffered from a big smile has...... been "smile corrected" using individual phase masks for each emitter. The external cavity consists of the laser bar, both fast and slow axis micro collimators, smile correcting phase mask, 6.5x beam expanding lens combination, a 1200 lines/mm reflecting grating with 85% efficiency in the first order...

  1. Nonstationary Narrow-Band Response and First-Passage Probability

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    The notion of a nonstationary narrow-band stochastic process is introduced without reference to a frequency spectrum, and the joint distribution function of two consecutive maxima is approximated by use of an envelope. Based on these definitions the first passage problem is treated as a Markov...... point process. The theory is applied to the response of a linear oscillator excited by a stationary process from t equals 0, and a simple algebraic relation between the nonstationary and stationary correlation functions of the response is derived....

  2. Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

    Directory of Open Access Journals (Sweden)

    Fèlix Grases

    2014-03-01

    Full Text Available We describe the case of a patient with calcium oxalate monohydrate and calcium oxalate dihydrate calculi occluded in cavities. All those calculi were located inside narrow cavities covered with a thin epithelium that permits their visualization. Urinary biochemical analysis showed high calciuria, not hypercalciuria, hypocitraturia, and a ratio [calcium]/[citrate] >0.33. The existence of cavities of very low urodynamic efficacy was decisive in the formation of such calculi. It is important to emphasize that we observed a thin epithelium covering such cavities, demonstrating that this epithelium may be formed after the development of the calculi through a re-epithelialization process.

  3. Masas de agujeros negros en Narrow Line Seyfert 1

    Science.gov (United States)

    Schmidt, E.; Ferreiro, D.; Oio, G.; Vega, L.; Donoso, L.

    We describe two of the ways to estimate black hole masses in AGN, and then we estimate the black hole masses of 13 Narrow Line Seyfert 1 galaxies with the two methods: virial masses, using the correlation found by Greene & Ho (2005, ApJ, 630, 122); and the correlation found by Tremaine et al. (2002, ApJ, 574, 740). For this work we analyzed the optical spectroscopy data we obtained from CASLEO (San Juan). We compare the results obtained through both methods. FULL TEXT IN SPANISH

  4. Fatigue failure of materials under narrow band random vibrations. I.

    Science.gov (United States)

    Huang, T. C.; Hubbard, R. B.; Lanz, R. W.

    1971-01-01

    A novel approach for the study of fatigue failure of materials under the multifactor influence of narrow band random vibrations is developed. The approach involves the conduction of an experiment in conjunction with various statistical techniques. Three factors including two statistical properties of the excitation or response are considered and varied simultaneously. A minimum of 6 tests for 3 variables is possible for a fractional f actorial design. The four coefficients of the predicting equation can be independently estimated. A look at 3 predicting equations shows the predominant effect of the root mean square stress of the first order equation.

  5. Narrow groove gas metal-arc welding of aluminum

    International Nuclear Information System (INIS)

    Armstrong, R.E.

    1975-01-01

    The Gas Metal-Arc (GMA) welding process is explained and the equipment used described with an analysis of power supply function and the action of the arc, followed by discussion of general applications and problems. GMA braze welding of beryllium is then described, as is the development of a special high purity filler wire and a narrow deep groove joint design for improved weld strength in beryllium. This joint design and the special wire are applied in making high strength welds in high strength aluminum for special applications. High speed motion pictures of the welding operation are shown to illustrate the talk. (auth)

  6. The Meteorology of Storms that Produce Narrow Bipolar Events

    Science.gov (United States)

    Lang, Timothy; McCaul, Bill; Fuchs, Brody; Cummer, Steve

    2013-01-01

    Narrow Bipolar Event's (NBE) are compact ( 10 kW in VHF), and impulsive (approx 10 micro s) electrical discharges in thunderstorms, also known as compact intracloud discharges (CIDs). Can be either positive or negative polarity and have distinctive broadband waveform signatures sometimes confused for +CGs in the past by NLDN and other networks. NBEs are related to lightning but are likely optically "dark". As revealed by VHF sensors (both satellite and ground): (1) The most powerful lightning-­-related VHF sources observed (2) Tend to occur at the beginning of intracloud discharges (3) Difficult to estimate altitude properly due to receiver saturation.

  7. Characteristics of nighttime E-region over Arecibo: Dependence on solar flux and geomagnetic variations

    Science.gov (United States)

    Raizada, Shikha; Brum, Christiano G. M.; Mathews, John D.; Gonzalez, Cristina; Franco, Efmi

    2018-04-01

    Electron concentration (Ne) inferred from Incoherent Scatter Radar (ISR) measurements has been used to determine the influence of solar flux and geomagnetic activity in the ionospheric E-region over Arecibo Observatory (AO). The approach is based on the determination of column integrated Ne, referred to as E-region total electron content (ErTEC) between 80 and 150 km altitude regions. The results discussed in this work are for the AO nighttime period. The study reveals higher ErTEC values during the low solar flux periods for all the seasons except for summer period. It is found that the E-region column abundance is higher in equinox periods than in the winter for low solar activity conditions. The column integrated Ne during the post-sunset/pre-sunrise periods always exceeds the midnight minima, independent of season or solar activity. This behavior has been attributed to the variations in the coupling processes from the F-region. The response of ErTEC to the geomagnetic variability is also examined for different solar flux conditions and seasons. During high solar flux periods, changes in Kp cause an ErTEC increase in summer and equinox, while producing a negative storm-like effect during the winter. Variations in ErTEC due to geomagnetic activity during low solar flux periods produce maximum variability in the E-region during equinox periods, while resulting in an increase/decrease in ErTEC before local midnight during the winter/summer periods, respectively.

  8. EVOLUTION OF INTERMITTENCY IN THE SLOW AND FAST SOLAR WIND BEYOND THE ECLIPTIC PLANE

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzaszek, A.; Macek, W. M. [Space Research Centre, Polish Academy of Sciences, Warsaw (Poland); Echim, M. [The Belgian Institute for Space Aeronomy, Brussels (Belgium); Bruno, R., E-mail: anna.wawrzaszek@cbk.waw.pl, E-mail: marius.echim@oma.be, E-mail: macek@cbk.waw.pl, E-mail: roberto.bruno@iaps.inaf.it [Institute for Space Astrophysics and Planetology, Roma (Italy)

    2015-12-01

    We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997–1998 and 2007–2008) and one solar maximum (1999–2001). In particular, by modeling a multifractal spectrum, we revealed the intermittent character of turbulence in the small-scale fluctuations of the magnetic field embedded in the slow and fast solar wind. Generally, at small distances from the Sun, in both the slow and fast solar wind, we observe the high degree of multifractality (intermittency) that decreases somewhat slowly with distance and slowly with latitude. The obtained results seem to suggest that generally intermittency in the solar wind has a solar origin. However, the fast and slow streams, shocks, and other nonlinear interactions can only be considered as the drivers of the intermittent turbulence. It seems that analysis shows that turbulence beyond the ecliptic plane evolves too slowly to maintain the intermittency with the distance and latitude. Moreover, we confirm that the multifractality and intermittency are at a lower level than in the ecliptic, as well as the existence of symmetry with respect to the ecliptic plane, suggesting that there are similar turbulent properties observed in the two hemispheres.

  9. EVOLUTION OF INTERMITTENCY IN THE SLOW AND FAST SOLAR WIND BEYOND THE ECLIPTIC PLANE

    International Nuclear Information System (INIS)

    Wawrzaszek, A.; Macek, W. M.; Echim, M.; Bruno, R.

    2015-01-01

    We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997–1998 and 2007–2008) and one solar maximum (1999–2001). In particular, by modeling a multifractal spectrum, we revealed the intermittent character of turbulence in the small-scale fluctuations of the magnetic field embedded in the slow and fast solar wind. Generally, at small distances from the Sun, in both the slow and fast solar wind, we observe the high degree of multifractality (intermittency) that decreases somewhat slowly with distance and slowly with latitude. The obtained results seem to suggest that generally intermittency in the solar wind has a solar origin. However, the fast and slow streams, shocks, and other nonlinear interactions can only be considered as the drivers of the intermittent turbulence. It seems that analysis shows that turbulence beyond the ecliptic plane evolves too slowly to maintain the intermittency with the distance and latitude. Moreover, we confirm that the multifractality and intermittency are at a lower level than in the ecliptic, as well as the existence of symmetry with respect to the ecliptic plane, suggesting that there are similar turbulent properties observed in the two hemispheres

  10. Narrow head-tail radio galaxies at very high resolution

    Science.gov (United States)

    Terni de Gregory, B.; Feretti, L.; Giovannini, G.; Govoni, F.; Murgia, M.; Perley, R. A.; Vacca, V.

    2017-12-01

    Aims: Narrow-angle tailed (NAT) sources in clusters of galaxies can show on the large scale very narrow tails that are unresolved even at arcsecond resolution. These sources could therefore be classified as one-sided jets. The aim of this paper is to gain new insight into the structure of these sources, and establish whether they are genuine one-sided objects, or if they are two-sided sources. Methods: We observed a sample of apparently one-sided NAT sources at subarcsecond resolution to obtain detailed information on their structure in the nuclear regions of radio galaxies. Results: Most radio galaxies are found to show two-sided jets with sharp bends, and therefore the sources are similar to the more classical NATs, which are affected by strong projection effects. The reduced images (FITS) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/608/A58

  11. Extended Narrow-Line Region in Seyfert Galaxies

    Directory of Open Access Journals (Sweden)

    Enrico Congiu

    2017-10-01

    Full Text Available We present our recent results about the extended narrow-line region (ENLR of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212 obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1 galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a the contribution of shocks in ionizing the high velocity gas, (b the complex kinematics showed by the profile of the emission lines, (c the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  12. Flow of pedestrians through narrow doors with different competitiveness

    International Nuclear Information System (INIS)

    Garcimartín, A; Pastor, J M; Zuriguel, I; Parisi, D R; Martín-Gómez, C

    2016-01-01

    We report a thorough analysis of the intermittent flow of pedestrians through a narrow door. The observations include five different sets of evacuation drills with which we have investigated the effect of door size and competitiveness on the flow dynamics. Although the outcomes are in general compatible with the existence of the faster-is-slower effect, the temporal evolution of the instantaneous flow rate provides evidence of new features. These stress the crucial role of the number of people performing the tests, which has an influence on the obtained results. Once the transients at the beginning and end of the evacuation are removed, we have found that the time lapses between the passage of two consecutive pedestrians display heavy-tailed distributions in all the scenarios studied. Meanwhile, the distribution of burst sizes decays exponentially; this can be linked to a constant probability of finding a long-lasting clog during the evacuation process. Based on these results, a discussion is presented on the caution that should be exercised when measuring or describing the intermittent flow of pedestrians through narrow doors. (paper: interdisciplinary statistical mechanics)

  13. Extended Narrow-Line Region in Seyfert Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Congiu, Enrico [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Contini, Marcella [School of Physics and Astronomy, Tel Aviv University, Tel Aviv (Israel); Ciroi, Stefano; Cracco, Valentina [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Di Mille, Francesco [Las Campanas Observatory, La Serena (Chile); Berton, Marco [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero, E-mail: enrico.congiu@phd.unipd.it [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy)

    2017-10-24

    We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  14. Sedimentation of an ellipsoidal particle in narrow tubes

    Science.gov (United States)

    Huang, Haibo; Yang, Xin; Lu, Xi-yun

    2014-05-01

    Sedimentation behaviours of an ellipsoidal particle in narrow and infinitely long tubes are studied by a multi-relaxation-time lattice Boltzmann method (LBM). In the present study, both circular and square tubes with 12/13 ⩽ D/A ⩽ 2.5 are considered with the Galileo number (Ga) up to 150, where D and A are the width of the tube and the length of major axis of the ellipsoid, respectively. Besides three modes of motion mentioned in the literature, two novel modes are found for the narrow tubes in the higher Ga regime: the spiral mode and the vertically inclined mode. Near a transitional regime, in terms of average settling velocity, it is found that a lighter ellipsoid may settle faster than a heavier one. The relevant mechanism is revealed. The behaviour of sedimentation inside the square tubes is similar to that in the circular tubes. One significant difference is that the translation and rotation of ellipsoid are finally constrained to a diagonal plane in the square tubes. The other difference is that the anomalous rolling mode occurs in the square tubes. In this mode, the ellipsoid rotates as if it is contacting and rolling up one corner of the square tube when it settles down. Two critical factors that induce this mode are identified: the geometry of the tube and the inertia of the ellipsoid.

  15. Collecting Solar Energy. Solar Energy Education Project.

    Science.gov (United States)

    O'Brien, Alexander

    This solar energy learning module for use with junior high school students offers a list of activities, a pre-post test, job titles, basic solar energy vocabulary, and diagrams of solar energy collectors and installations. The purpose is to familiarize students with applications of solar energy and titles of jobs where this knowledge could be…

  16. Wide and Narrow CMEs and Their Source Explosions Observed at the Spring 2003 SOHO-Sun-Ulysses Quadrature

    Science.gov (United States)

    Suess, Steven; Corti, G.; Poletto, G.; Sterling, A.; Moore, R.

    2006-01-01

    At the time of the spring 2003 Ulysses-SOHO-Sun quadrature, Ulysses was off the East limb of the Sun at 14.5 degrees north latitude and 4.91 AU. LASCO/C2 images show small transient events that originated from near the limb on May 25, 26 and 27 in the north-east quadrant, along with a large Coronal Mass Ejection (CME) that originated from an active region near disk center on May 26. Ulysses data bear clear signatures of the large CME, specifically including an enhanced abundance of highly ionized Fe. SOHO/UVCS spectra at 1.75 solar radii, near the radial direction to Ulysses, give no evidence of emission from high temperature lines, even for the large CME: instead, for the small events, occasional transient high emission in cool lines was observed, such as the CIII 977 Angstrom line usually absent at coronal levels. Each of these events lasted ca. 1 hour or less and never affected lines from ions forming above ca. 106K. Compact eruptions in Helium 304 Angstrom EIT images, related to the small UVCS transients, were observed at the limb of the Sun over the same period. At least one of these surge events produced a narrow CME observed in LASCO/C2. Most probably all these events are compact magnetic explosions (surges/jets, from around a small island of included polarity) which ejected cool material from lower levels. Ulysses data have been analyzed to find evidence of the cool, narrow CME events, but none or little was found. This puzzling scenario, where events seen by UVCS have no in situ counterparts and vice versa, can be partially explained once the region where the large CME originated is recognized as being at the center of the solar disk so that the CME material was actually much further from the Sun than the 1.7 Rsun height of the UVCS slit off the limb. Conversely, the narrow events may simply have missed Ulysses or been too brief for reliable signatures in composition and ionization state. A basic feature demonstrated by these observations is that large

  17. Long-term north-south asymmetry in solar wind speed inferred from geomagnetic activity: A new type of century-scale solar oscillation?

    DEFF Research Database (Denmark)

    Mursula, K.; Zieger, B.

    2001-01-01

    A significant and very similar annual variation in solar wind speed and in geomagnetic activity was recently found around all the four solar cycle minima covered by direct SW observations since mid-1960's. We have shown that the phase of this annual variation reverses with the Sun's polarity...... reversal, depicting a new form of 22-year periodicity. The annual variation results from a small north-south asymmetry in SW speed distribution where the minimum speed region is shifted toward the northern magnetic hemisphere. Here we study the very long-term evolution of the annual variation using early...... the southern magnetic hemisphere. This change of asymmetry suggests for a possible new form of century-scale oscillation in the north-south asymmetry of the Sun. We explain the asymmetry in terms of a relic magnetic field dislocated slightly in the north-south direction from the heliographic equator...

  18. Solar club

    CERN Multimedia

    Solar club

    2013-01-01

    SOLAR CLUB Le  CERN-Solar-Club souhaite une  très bonne année 2013 à tous les Cernois et Cernoises, et remercie encore une fois  tous ceux et celles qui, fin octobre, par leur vote, nous ont permis de finir dans les 5 premiers du concours "Conforama Solidaire" et ainsi financer nôtre projet "énergie solaire et eau potable pour Kilela Balanda" en République Démocratique du Congo (voir : http://www.confo.ch/solidarite/?lang=fr). Nous vous annoncons également notre Assemblée Générale Annuelle jeudi 21 février à 18 h 00 Salle C, 1er étage, Bât. 61 Vous êtes les bienvenus si vous souhaitez en savoir un peu plus sur les énergies renouvelables.

  19. Fisica solare

    CERN Document Server

    Degl’Innocenti, Egidio Landi

    2008-01-01

    Il volume è un'introduzione alla Fisica Solare che si propone lo scopo di illustrare alla persona che intende avvicinarsi a questa disciplina (studenti, dottori di ricerca, ricercatori) i meccanismi fisici che stanno alla base della complessa fenomenologia osservata sulla stella a noi più vicina. Il volume non ha la pretesa di essere esauriente (basta pensare che la fisica solare spazia su un gran numero di discipline, quali la Fisica Nucleare, la Termodinamica, L'Elettrodinamica, la Fisica Atomica e Molecolare, la Spettoscopia in tutte le bande dello spettro elettromagnetico, la Magnetoidrodinamica, la Fisica del Plasma, lo sviluppo di nuova strumentazione, l'Ottica, ecc.). Piuttosto, sono stati scelti un numero di argomenti di rilevanza fondamentale nello studio presente del Sole (soprattutto nei riguardi delle osservazioni da terra con grandi telescopi) e su tali argomenti si è cercato di dare una panoramica generale, inclusiva dell'evoluzione storica, senza scendere in soverchi dettagli. Siccome la Fis...

  20. Abooming area:non-fullerene acceptors for organic solar cells

    Directory of Open Access Journals (Sweden)

    QU Yangkun

    2016-12-01

    Full Text Available Organic solar cells have been extensively investigated in the last decade because they are one of the very important solutions to the global energy crisis.While predominant electron acceptor materials for organic solar cell are focused on fullerene and its derivatives,scientists are now more desperately looking for new alternative acceptor materials because fullerene acceptors face the challenges of narrow absorption spectrum,low solubility,high cost and non-environmental friendly synthesis processes.Non-fullerene electron acceptors have drawn great attention recently and have been widely used in organic solar cells because they have the great advantages of wide absorption spectrum,high solubility,precise structural controllability,and good processability.In this review paper,we summarize the most significant progresses in the area of non-fullerene organic solar cell acceptors during the last 6 years and we look forward to a bright future of non-fullerene organic solar cells.

  1. Solar Training Network and Solar Ready Vets

    Energy Technology Data Exchange (ETDEWEB)

    Dalstrom, Tenley Ann

    2016-09-14

    In 2016, the White House announced the Solar Ready Vets program, funded under DOE's SunShot initiative would be administered by The Solar Foundation to connect transitioning military personnel to solar training and employment as they separate from service. This presentation is geared to informing and recruiting employer partners for the Solar Ready Vets program, and the Solar Training Network. It describes the programs, and the benefits to employers that choose to connect to the programs.

  2. Concentrated solar power generation using solar receivers

    Science.gov (United States)

    Anderson, Bruce N.; Treece, William Dean; Brown, Dan; Bennhold, Florian; Hilgert, Christoph

    2017-08-08

    Inventive concentrated solar power systems using solar receivers, and related devices and methods, are generally described. Low pressure solar receivers are provided that function to convert solar radiation energy to thermal energy of a working fluid, e.g., a working fluid of a power generation or thermal storage system. In some embodiments, low pressure solar receivers are provided herein that are useful in conjunction with gas turbine based power generation systems.

  3. Solar flares

    International Nuclear Information System (INIS)

    Kaastra, J.S.

    1985-01-01

    In this thesis an electrodynamic model for solar flares is developed. The main theoretical achievements underlying the present study are treated briefly and the observable flare parameters are described within the framework of the flare model of this thesis. The flare model predicts large induced electric fields. Therefore, acceleration processes of charged particles by direct electric fields are treated. The spectrum of the accelerated particles in strong electric fields is calculated, 3 with the electric field and the magnetic field perpendicular and in the vicinity of an X-type magnetic neutral line. An electromagnetic field configuration arises in the case of a solar flare. A rising current filament in a quiescent background bipolar magnetic field causes naturally an X-type magnetic field configuration below the filament with a strong induced electric field perpendicular to the ambient magnetic field. This field configuration drives particles and magnetic energy towards the neutral line, where a current sheet is generated. The global evolution of the fields in the flare is determined by force balance of the Lorentz forces on the filament and the force balance on the current sheet. The X-ray, optical and radio observations of a large solar flare on May 16, 1981 are analyzed. It is found that these data fit the model very well. (Auth.)

  4. Solar chameleons

    International Nuclear Information System (INIS)

    Brax, Philippe; Zioutas, Konstantin

    2010-01-01

    We analyze the creation of chameleons deep inside the Sun (R∼0.7R sun ) and their subsequent conversion to photons near the magnetized surface of the Sun. We find that the spectrum of the regenerated photons lies in the soft x-ray region, hence addressing the solar corona problem. Moreover, these back-converted photons originating from chameleons have an intrinsic difference with regenerated photons from axions: their relative polarizations are mutually orthogonal before Compton interacting with the surrounding plasma. Depending on the photon-chameleon coupling and working in the strong coupling regime of the chameleons to matter, we find that the induced photon flux, when regenerated resonantly with the surrounding plasma, coincides with the solar flux within the soft x-ray energy range. Moreover, using the soft x-ray solar flux as a prior, we find that with a strong enough photon-chameleon coupling, the chameleons emitted by the Sun could lead to a regenerated photon flux in the CAST magnetic pipes, which could be within the reach of CAST with upgraded detector performance. Then, axion helioscopes have thus the potential to detect and identify particle candidates for the ubiquitous dark energy in the Universe.

  5. Solar Chameleons

    CERN Document Server

    Brax, Philippe

    2010-01-01

    We analyse the creation of chameleons deep inside the sun and their subsequent conversion to photons near the magnetised surface of the sun. We find that the spectrum of the regenerated photons lies in the soft X-ray region, hence addressing the solar corona problem. Moreover, these back-converted photons originating from chameleons have an intrinsic difference with regenerated photons from axions: their relative polarisations are mutually orthogonal before Compton interacting with the surrounding plasma. Depending on the photon-chameleon coupling and working in the strong coupling regime of the chameleons to matter, we find that the induced photon flux, when regenerated resonantly with the surrounding plasma, coincides with the solar flux within the soft X-ray energy range. Moreover, using the soft X-ray solar flux as a prior, we find that with a strong enough photon-chameleon coupling the chameleons emitted by the sun could lead to a regenerated photon flux in the CAST pipes, which could be within the reach...

  6. Solar Forcing of climate fluctuations in East Africa recorded in southeastern Mediterranean sediments

    Science.gov (United States)

    Hamann, Y.; Dulski, P.; Hajdas, I.; Ehrmann, W. U.; Schmiedl, G. H.; Haug, G. H.

    2010-12-01

    The proportions of terrigenous components in Mediterranean sediments derived from the atmosphere and rivers strongly depend on climate conditions in the source areas. The rainfall regimes of the northern and central part of the African continent are controlled by an interplay between global climate patterns and the regional hydrological balance. High-resolution XRF element records of a marine sediment core of the southeastern Levantine Sea (Mediterranean Sea; GeoTü SL112, 32° 44.52 N, 34° 39.02 E, water depth: 892 m) indicate distinctive changes in the sediment supply to the southeastern Mediterranean by the Nile River as well as the influx of aeolian dust from the Saharan desert. We observe minima in the concentration of the element iron (Fe), which we interpret as minima in dust input, during the well-known solar minima Oort, Wolf, Spoerer, Maunder, and Dalton. Wavelet analyses reveals a close correspondence in the periodicity in Fe input with the typical frequencies of solar cycles of about 90 and 210 years during the last 1400 years. Furthermore, the Fe record from the Levantine Sea sediments shows a remarkable similarity with the lake level record of Lake Naivasha in the eastern branch of the East African Rift and the pre-colonial drought history of Lake Malawi in the southern part of the African Rift Valley. Enhanced Saharan dust flux as indicated by high Fe content in the Levantine Sea core coincides with well-known droughts in equatorial east Africa as indicated by Lake Naivasha lowstands.

  7. 78 FR 50377 - Narrow Woven Ribbons With Woven Selvedge From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2013-08-19

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-583-844] Narrow Woven Ribbons With Woven Selvedge From Taiwan: Final Results of Antidumping Duty Administrative Review; 2011-2012 AGENCY... administrative review of the antidumping duty order on narrow woven ribbons with woven selvedge (narrow woven...

  8. 77 FR 82 - Correction to Initiation of 2010-2011 Antidumping Duty Administrative Review: Narrow Woven...

    Science.gov (United States)

    2012-01-03

    ... 2010-2011 Antidumping Duty Administrative Review: Narrow Woven Ribbons With Woven Selvedge From Taiwan... woven ribbons with woven selvedge (narrow woven ribbons) from Taiwan. See Initiation of Antidumping and... review of narrow woven ribbons from Taiwan is correct and remains unchanged. This correction is issued...

  9. 77 FR 72825 - Narrow Woven Ribbons With Woven Selvedge From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2012-12-06

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-583-844] Narrow Woven Ribbons With Woven Selvedge From Taiwan: Final Results of Antidumping Duty Administrative Review; 2010-2011 AGENCY... administrative review of the antidumping duty order on narrow woven ribbons with woven selvedge (narrow woven...

  10. Instrument design of 1.5-m aperture solar optical telescope for the Solar-C Mission

    Science.gov (United States)

    Suematsu, Yoshinori; Katsukawa, Yukio; Shimizu, Toshifumi; Ichimoto, Kiyoshi

    2017-11-01

    A 1.5 m aperture optical telescope is planned for the next Japanese solar mission SOLAR-C as one of major three observing instruments. The optical telescope is designed to provide high-angular-resolution investigation of lower atmosphere from the photosphere to the uppermost chromosphere with enhanced spectroscopic and spectropolarimetric capability covering a wide wavelength region from 280 nm to 1100 nm. The opto-mechanical and -thermal performance of the telescope is crucial to attain high-quality solar observations and we present a study of optical and structural design of the large aperture space solar telescope, together with conceptual design of its accompanying focal plane instruments: wide-band and narrow-band filtergraphs and a spectro-polarimeter for high spatial and temporal observations in the solar photospheric and chromospheric lines useful for sounding physical condition of dynamical phenomena.

  11. Solar cities

    International Nuclear Information System (INIS)

    Roaf, S.; Fuentes, M.; Gupta, R.

    2005-01-01

    Over the last decade, climate change has moved from being the concern of few to a widely recognized threat to humanity itself and the natural environment. The 1990s were the warmest decade on record, and ever-increasing atmospheric levels of greenhouse gases such as carbon dioxide (CO/sub 2/), could, if left unchecked lead to serious consequences globally, including increased risks of droughts, floods and storms, disruption to agriculture, rising sea levels and the spread of disease. The contribution of anthropogenic emissions of carbon dioxide has been recognized as the principal cause of the atmospheric changes that drive these climate trends. Globally, buildings are the largest source of indirect carbon emissions. In 2000, the UK Royal Commission on Environmental Pollution estimated that in order to stabilise carbon emissions at levels, which avoid catastrophic alterations in the climate, we would have to reduce emissions from the built environment by at least 60% by 2050 and 80% by 2100 relative to 1997 levels. Studies of the Oxford Ecohouse have demonstrated that it is not difficult to reduce carbon emissions from houses by 60% or more through energy efficiency measures, but it is only possible to reach the 90% level of reductions required by using renewable energy technologies. Solar energy technologies have been the most successfully applied of all renewable to date largely because they are the only systems that can be incorporated easily into the urban fabric. In addition, the short fossil fuel horizons that are predicted (c. 40 years left for oil and 65 years for gas) will drive the markets for solar technologies. For these reasons, the cities of the future will be powered by solar energy, to a greater or lesser extent, depending on the city form and location. In recognition of the need to move rapidly towards a renewable energy future, a group of international cities, including Oxford, have started the Solar City Network. In this paper we outline the

  12. The narrow range of perceived predation: a 19 group study

    Directory of Open Access Journals (Sweden)

    Olivier Mesly

    2013-05-01

    Full Text Available This paper rests largely on the works of Mesly (1999 to 2012. It argues that the phenomenon of perceived predation as a functional behavioural phenomenon is subjected to certain limits, a finding based on studies performed on 19 different groups spread over a four-year span. It also finds a constant of k = 1.3 which reflects the invariant nature of perceived predation. These findings add to the theory of financial predation which stipulates that financial predators operate below the limits of detection pertaining to their customers (and market regulators. They are experts at minimizing the perception that clients could have that they are after their money, causing them financial harm, by surprise (perceived predation. Understanding the narrow range in which financial predators operate is setting the grounds to offer better protection to investors and to implementing better control and punitive measures.

  13. Narrow band interference cancelation in OFDM: Astructured maximum likelihood approach

    KAUST Repository

    Sohail, Muhammad Sadiq

    2012-06-01

    This paper presents a maximum likelihood (ML) approach to mitigate the effect of narrow band interference (NBI) in a zero padded orthogonal frequency division multiplexing (ZP-OFDM) system. The NBI is assumed to be time variant and asynchronous with the frequency grid of the ZP-OFDM system. The proposed structure based technique uses the fact that the NBI signal is sparse as compared to the ZP-OFDM signal in the frequency domain. The structure is also useful in reducing the computational complexity of the proposed method. The paper also presents a data aided approach for improved NBI estimation. The suitability of the proposed method is demonstrated through simulations. © 2012 IEEE.

  14. Main features of narrow sociological theories explaining mental disorders

    Directory of Open Access Journals (Sweden)

    Opalić Petar

    2006-01-01

    Full Text Available In the introduction, the author states that sociological theories explaining mental disorders in the narrow sense have originated as an opposition to medical, i.e. biological model of interpreting mental disorders. With regard to this, the following sociological theories explaining mental disorders are presented in more detail: theory of anomie by Durkheim and Merton (with Merton’s typology of deviant behavior, social roles theory by Parsons, labeling theory by Scheff and other authors, theoretical career model of the mentally ill, the concept of psychic disorder of etnomethodology and finally, the anti-psychiatric interpretation of mental disorders. It is concluded that, although historically older, sociological theories of the onset of mental disorders are filling the epistemological void that occurred in understanding the role of society on the whole and a series of social factors particularly on the different aspects of understanding mental disorders.

  15. Density Fluctuations of Hard-Sphere Fluids in Narrow Confinement

    Directory of Open Access Journals (Sweden)

    Kim Nygård

    2016-02-01

    Full Text Available Spatial confinement induces microscopic ordering of fluids, which in turn alters many of their dynamic and thermodynamic properties. However, the isothermal compressibility has hitherto been largely overlooked in the literature, despite its obvious connection to the underlying microscopic structure and density fluctuations in confined geometries. Here, we address this issue by probing density profiles and structure factors of hard-sphere fluids in various narrow slits, using x-ray scattering from colloid-filled nanofluidic containers and integral-equation-based statistical mechanics at the level of pair distributions for inhomogeneous fluids. Most importantly, we demonstrate that density fluctuations and isothermal compressibilities in confined fluids can be obtained experimentally from the long-wavelength limit of the structure factor, providing a formally exact and experimentally accessible connection between microscopic structure and macroscopic, thermodynamic properties. Our approach will thus, for example, allow direct experimental verification of theoretically predicted enhanced density fluctuations in liquids near solvophobic interfaces.

  16. Crystallization of Poly(3-hexylthiophene Nanofiber in a Narrow Groove

    Directory of Open Access Journals (Sweden)

    Satoshi Kushi

    2016-06-01

    Full Text Available Whisker-type poly(3-hexylthiophene-2,5-diyl (P3HT nanofibers were aligned by restricting their growth direction using an approximately 100–1000 nm wide narrow groove fabricated by thermal nanoimprinting. In grooves made of an amorphous fluoropolymer (CYTOP™ with widths of less than 1500 nm, the nanofibers oriented uniaxially perpendicular to the groove and their length was limited to the width of the groove. This result indicates that the nucleation of nanofibers tends to be selectively promoted near the interface of CYTOP™ with fluoro-groups, and nanofiber growth perpendicular to the wall is promoted because P3HT molecules are supplied more frequently from the center of the groove. Furthermore, the orientation induced anisotropic conductivity, and the conductivity parallel to the oriented nanofibers was more than an order of magnitude higher than that perpendicular to the oriented nanofibers.

  17. Model for diffusion of a narrow beam of charged particles

    International Nuclear Information System (INIS)

    Eisenhauer, C.

    1980-01-01

    A simple analytic expression is presented to describe the three-dimensioned spatial distribution of flux or energy deposition by a narrow beam of charged particles. In this expression distances are expressed in terms of a scaling parameter that is proportional to the mean square scattering angle in a single collision. Finite ranges are expressed in terms of the continuous-slowing-down range. Track-length distributions for one-velocity particles and energy deposition for electrons are discussed. Comparisons with rigorous Monte Carlo calculations show that departures from the analytic expression can be expressed as a slowly varying function of order unity. This function can be used as a basis for interpolation over a wide range of source energies and materials

  18. Flow characteristics of ice slurry in narrow tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kumano, Hiroyuki; Hirata, Tetsuo; Shouji, Ryouta; Hagiwara, Yosuke [Department of Mechanical Systems Engineering, Shinshu University, 4-17-1, Wakasato, Nagano-shi, Nagano 380-8553 (Japan); Shirakawa, Michito [Toyota Motor Corporation, 1 Toyota-cho, Toyota, Aichi 471-8571 (Japan)

    2010-12-15

    Flow characteristics of ice slurry were experimentally investigated using narrow tubes. Reynolds number, the diameter of the tubes and the ice packing factor (IPF) were varied as the experimental parameters. Theoretical analysis was carried out using the experimental results. For laminar flow, it was found that the ratio of the coefficients of pipe friction increases with the IPF, and the rate of increase is high in the case of a low Reynolds number. For turbulent flow, the ratio of the coefficients of pipe friction was 1 for each condition in the case of a low IPF. The ratio of coefficients of pipe friction then decreased slightly at a particular IPF and increased with the IPF in the high-IPF region. In theoretical analysis, it was found that the flow characteristics of ice slurry can be treated as those of pseudoplastic fluid and clarified using the apparent Reynolds number. (author)

  19. Narrow-linewidth passband filter for ultraviolet rotational Raman imaging.

    Science.gov (United States)

    Finkelstein, N D; Lempert, W R; Miles, R B

    1997-04-15

    We present a narrow-passband spectral filter capable of frequency-resolved imaging of rotational Raman light scattering with strong spectral rejection of out-of-band Raman, Rayleigh, and Mie scattering. The filter is based on mercury-vapor absorption, and subsequent resonant fluorescence and has a passband of less than 1 cm(-1). It is paired with an injection-seeded, cavity-locked, frequency-tripled Ti:sapphire laser that produces >30 mJ/pulse of single-mode, tunable light in the vicinity of 253.7 nm. The laser and filter are combined to spectrally resolve scattering from individual rotational Raman lines of nitrogen and oxygen.

  20. Narrow bandpass tunable terahertz filter based on photonic crystal cavity.

    Science.gov (United States)

    He, Jinglong; Liu, Pingan; He, Yalan; Hong, Zhi

    2012-02-20

    We have fabricated a very narrow bandpass tunable terahertz (THz) filter based on a one-dimensional photonic crystal cavity. Since the filter consists of silicon wafers and air spacers, it has a very high quality factor of about 1500. The full width at half maximum (FWHM) of the passband is only about 200 MHz, and the peak transmission is higher than -4 dB. Besides, the central frequency can be tuned rapidly over the entire bandgap with the length of cavity adjusted by a motorized linear stage. Further analytical calculations indicate that a high-Q tunable filter with both high peak transmission and wide tunable range is possible if thinner silicon layers are used. © 2012 Optical Society of America

  1. High unexpected genetic diversity of a narrow endemic terrestrial mollusc

    Directory of Open Access Journals (Sweden)

    Pedro M. Madeira

    2017-03-01

    Full Text Available The Iberian Peninsula has an extensive record of species displaying strong genetic structure as a result of their survival in isolated pockets throughout the Pleistocene ice ages. We used mitochondrial and nuclear sequence data to analyze phylogeographic patterns in endemic land snails from a valley of central Portugal (Vale da Couda, putatively assigned to Candidula coudensis, that show an exceptionally narrow distributional range. The genetic survey presented here shows the existence of five main mitochondrial lineages in Vale da Couda that do not cluster together suggesting independent evolutionary histories. Our results also indicate a departure from the expectation that species with restricted distributions have low genetic variability. The putative past and contemporary models of geographic distribution of Vale da Couda lineages are compatible with a scenario of species co-existence in more southern locations during the last glacial maximum (LGM followed by a post-LGM northern dispersal tracking the species optimal thermal, humidity and soil physical conditions.

  2. Patterns of granular convection and separation in narrow vibration bed

    Science.gov (United States)

    Liu, Chuanping; Wu, Ping; Wang, Li; Tong, Lige; Yin, Shaowu

    2017-06-01

    Granular convection/separation of single and binary component particles are studied in a narrow vibration bed, respectively. With filling the single light particles (molecular sieve beads), the bed exhibits five different states successively by increasing the vibration frequency f from 15Hz to 70 Hz (vibration strength Γ>3), as the global convection, symmetrical heap, unsymmetrical heap, local convection and pseudo solid. Comparatively, the granular bed of the single heavy particles (steel beads) is only in pseudo solid state at the above vibration condition. By filling binary component particles (molecular sieve and same size steel beads) instead of the single component, the bed shows similar convection state with that of the single molecular sieve beads, and the heavy steel beads are aggregated in the centre of convention roll as a core. Varying the initial distribution of binary component particles, the final convection and separation are not influenced, although the aggregation process of steel beads changes.

  3. Solar solution

    International Nuclear Information System (INIS)

    Shi Zhengrong

    2009-01-01

    China is facing enormous energy challenges. Everyone seems to know that we need to increase our energy supply by the equivalent of one power plant per week to support China's economic growth, which is allowing millions of people to enjoy better standards of living. Much less is known of the extent to which China has taken steps to mitigate the impact of that growing energy demand through incentives for greater efficiency and renewable energy. Policies include: Cutting energy intensity - 20 per cent between 2005 and 2010, saving five times as much CO 2 as the EU's goals. Cutting major pollutants by 10 per cent by 2010. Setting one of the world's most aggressive renewable energy standards: 15 per cent of national energy from renewables by 2020. Setting targets of 300 megawatts of installed solar by 2010, and 1.8 gigawatts by 2020, in the 2007 National Development and Reform Commission Renewable Energy Development Plan. Dedicating $180 billion for renewable energy by 2020. Imposing energy efficiency targets for the top 1,000 companies, a measure with greater carbon savings potential than most Western initiatives. Establishing building energy codes in all regions and extensive efficiency standards for appliances, which will be particularly important as China continues to grow. Targeting new buildings in major cities like Beijing, Shanghai and Chongqing, to achieve 65 per cent greater energy efficiency than local codes require. Closing thousands of older, smaller, dirtier power plants by 2010. China understands the economic development potential in clean energy technologies. Even the noted journalist Thomas Friedman has remarked that 'China is going green in a big way,' using domestic demand for cleaner energy to build low-cost, scalable green technologies. Suntech Power Holdings - now the world's largest solar photovoltaic (PV) module manufacturer, with operations around the globe - was just one of dozens of solar companies that realised the opportunity provided by

  4. Early solar physics

    CERN Document Server

    Meadows, A J

    1970-01-01

    Early Solar Physics reviews developments in solar physics, particularly the advent of solar spectroscopy and the discovery of relationships between the various layers of the solar atmosphere and between the different forms of solar activity. Topics covered include solar observations during 1843; chemical analysis of the solar atmosphere; the spectrum of a solar prominence; and the solar eclipse of December 12, 1871. Spectroscopic observations of the sun are also presented. This book is comprised of 30 chapters and begins with an overview of ideas about the sun in the mid-nineteenth century, fo

  5. Solar energy collector

    Science.gov (United States)

    Brin, Raymond L.; Pace, Thomas L.

    1978-01-01

    The invention relates to a solar energy collector comprising solar energy absorbing material within chamber having a transparent wall, solar energy being transmitted through the transparent wall, and efficiently absorbed by the absorbing material, for transfer to a heat transfer fluid. The solar energy absorbing material, of generally foraminous nature, absorbs and transmits the solar energy with improved efficiency.

  6. Solar constant values for estimating solar radiation

    International Nuclear Information System (INIS)

    Li, Huashan; Lian, Yongwang; Wang, Xianlong; Ma, Weibin; Zhao, Liang

    2011-01-01

    There are many solar constant values given and adopted by researchers, leading to confusion in estimating solar radiation. In this study, some solar constant values collected from literature for estimating solar radiation with the Angstroem-Prescott correlation are tested in China using the measured data between 1971 and 2000. According to the ranking method based on the t-statistic, a strategy to select the best solar constant value for estimating the monthly average daily global solar radiation with the Angstroem-Prescott correlation is proposed. -- Research highlights: → The effect of the solar constant on estimating solar radiation is investigated. → The investigation covers a diverse range of climate and geography in China. → A strategy to select the best solar constant for estimating radiation is proposed.

  7. PULSED KGd(WO42 RAMAN LASER: TOWARDS EMISSION LINEWIDTH NARROWING

    Directory of Open Access Journals (Sweden)

    V. G. Savitski

    2015-01-01

    Full Text Available The linewidth of a KGd(WO42 pulsed Raman laser is analysed experimentally for different configurations of the Raman and pump resonators: with narrow and broadband pump emission profiles, with and without linewidth narrowing elements in the Raman laser resonator, with and without injection seeding into the Raman cavity. The benefits of a narrow linewidth pump source in combination with linewidth narrowing elements in the Raman laser cavity for the efficient linewidth narrowing of the Raman emission are explained. 20 kW peak-power pulses at 1156 nm with 0,43 cm -1 emission linewidth are demonstrated from an injection seeded KGW Raman laser. 

  8. Coupling of Luminescent Solar Concentrators to Plasmonic Solar Cells

    Science.gov (United States)

    Wang, Shu-Yi

    To make inexpensive solar cells is a continuous goal for solar photovoltaic (PV) energy industry. Thin film solar cells of various materials have been developed and continue to emerge in order to replace bulk silicon solar cells. A thin film solar cell not only uses less material but also requires a less expensive refinery process. In addition, other advantages coming along with small thickness are higher open circuit voltage and higher conversion efficiency. However, thin film solar cells, especially those made of silicon, have significant optical losses. In order to address this problem, this thesis investigates the spectral coupling of thin films PV to luminescent solar concentrators (LSC). LSC are passive devices, consisting of plastic sheets embedded with fluorescent dyes which absorb part of the incoming radiation spectrum and emit at specific wavelength. The emitted light is concentrated by total internal reflection to the edge of the sheet, where the PVs are placed. Since the light emitted from the LSC edge is usually in a narrow spectral range, it is possible to employ diverse strategies to enhance PV absorption at the peak of the emission wavelength. Employing plasmonic nanostructures has been shown to enhance absorption of thin films via forward scattering, diffraction and localized surface plasmon. These two strategies are theoretically investigated here for improving the absorption and elevating the output power of a thin film solar cell. First, the idea of spectral coupling of luminescent solar concentrators to plasmonic solar cells is introduced to assess its potential for increasing the power output. This study is carried out employing P3HT/PC60BM organic solar cells and LSC with Lumogen Red dyes. A simplified spectral coupling analysis is employed to predict the power density, considering the output spectrum of the LSC equivalent to the emission spectrum of the dye and neglecting any angular dependence. Plasmonic tuning is conducted to enhance

  9. Solar Electricity

    Science.gov (United States)

    1988-01-01

    ARCO Solar manufactures PV Systems tailored to a broad variety of applications. PV arrays are routinely used at remote communications installations to operate large microwave repeaters, TV and radio repeaters rural telephone, and small telemetry systems that monitor environmental conditions. Also used to power agricultural water pumping systems, to provide electricity for isolated villages and medical clinics, for corrosion protection for pipelines and bridges, to power railroad signals, air/sea navigational aids, and for many types of military systems. ARCO is now moving into large scale generation for utilities.

  10. Photonic Nanostructures Design and Optimization for Solar Cell Application

    Directory of Open Access Journals (Sweden)

    Qian Liu

    2015-08-01

    Full Text Available In this paper, a semiconducting photonic nanostructure capable of wide range absorption and tunable optical resonance has been designed with a proposed theoretical optimization model. The design consists of ZnO/CdS core-shell nanowire arrays as well as multilayer thin films that act to absorb incident electromagnetic (EM waves over a broad frequency range. Theoretical, as well as numerical, studies of the nanostructure inside a solar cell plate have been conducted in order to validate the proposed microstructural design. Excellent energy absorption rates of EM waves have been achieved in the high frequency range by using the optical resonance of the nanowire array. By combining multilayer thin film with the core-shell nanowire in the unit cell of a photonic solar cell, a broadband high absorption has been achieved. Moreover, the geometry of the proposed photonic nanostructure is obtained through the implementation of a genetic algorithm. This avoids local minima and an optimized absorption rate of ~90% over the frequency range of 300 to 750 THz has been obtained in the solar cell.

  11. PERSISTENCE MAPPING USING EUV SOLAR IMAGER DATA

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, B. J. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Young, C. A., E-mail: barbara.j.thompson@nasa.gov [NASA Goddard Space Flight Center, Code 670, Greenbelt, MD 20771 (United States)

    2016-07-01

    We describe a simple image processing technique that is useful for the visualization and depiction of gradually evolving or intermittent structures in solar physics extreme-ultraviolet imagery. The technique is an application of image segmentation, which we call “Persistence Mapping,” to isolate extreme values in a data set, and is particularly useful for the problem of capturing phenomena that are evolving in both space and time. While integration or “time-lapse” imaging uses the full sample (of size N ), Persistence Mapping rejects ( N − 1)/ N of the data set and identifies the most relevant 1/ N values using the following rule: if a pixel reaches an extreme value, it retains that value until that value is exceeded. The simplest examples isolate minima and maxima, but any quantile or statistic can be used. This paper demonstrates how the technique has been used to extract the dynamics in long-term evolution of comet tails, erupting material, and EUV dimming regions.

  12. Various Barbs in Solar Filaments

    Science.gov (United States)

    Filippov, Boris

    2017-07-01

    Interest to lateral details of the solar filament shape named barbs, motivated by their relationship to filament chirality and helicity, showed their different orientation relative to the expected direction of the magnetic field. While the majority of barbs are stretched along the field, some barbs seem to be transversal to it and are referred to as anomalous barbs. We analyse the deformation of helical field lines by a small parasitic polarity using a simple flux rope model with a force-free field. A rather small and distant source of parasitic polarity stretches the bottom parts of the helical lines in its direction creating a lateral extension of dips below the flux-rope axis. They can be considered as normal barbs of the filament. A stronger and closer source of parasitic polarity makes the flux-rope field lines to be convex below its axis and creates narrow and deep dips near its position. As a result, the narrow structure, with thin threads across it, is formed whose axis is nearly perpendicular to the field. The structure resembles an anomalous barb. Hence, the presence of anomalous barbs does not contradict the flux-rope structure of a filament.

  13. SOLAR-FORCED 2600 BP AND LITTLE ICE AGE HIGHSTANDS OF THE CASPIAN SEA

    Directory of Open Access Journals (Sweden)

    S. B. Kroonenberg

    2008-01-01

    Full Text Available The researches combining a social, economic and ecological content, find out a generality of appendix area and global purpose. This purpose image is hidden behind the term sustainable development". These restrictions are presented as the multiplicative index of the development. This index is reflecting an information balance of a territory.The level of the Caspian Sea, the largest inland sea in the world, has fluctuated capriciously in history, with amplitudes up to 3 m in the last century, to 25m in the last millennium, and to over 150m since the Last Glacial. The results suggest that the last major highstands occurred around 2600 BP and in the Little Ice Age and coincide with global cooling events associated with minima in solar activity. This suggests that millennial precipitation changes in the Volga River drainage basin are also forced by solar activity.

  14. Solar Club

    CERN Multimedia

    Solar Club

    2010-01-01

    Le CERN Solar-Club vous invite à la présentation de sa participation dans : The Cyprus Institute Solar Car Challenge du 18 au 20 juin à Chypre . en réponse à l’invitation dudit institut, dans le cadre de la demande de Chypre pour joindre le CERN . Le Club y participera avec son vénérable Photon rénové , et la Dyane E-Solaire d’un de ses membres, rénové aussi . Après la présentation, le forum est ouvert pour toutes vos questions et propositions diverses, également dans d’autres domaines des énergies renouvelables . C’est aussi l’occasion pour joindre le Club ! Où, et Quand ? Le Mercredi 7 Avril à 19 h 00, au 6ème étage du Bât. Principal, (60-6-015) à la suite de l’AG des membres du Club , à 18h00 dans...

  15. El puente Verrazano-Narrows, en Nueva York

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1966-06-01

    Full Text Available The completion of the new Verrazano Narrows bridge, at the entrance to the New York harbour, signifies an outstanding triumph for civil engineering. Although the span of the Golden Gate bridge is very similar to this span the constructive methods, and many details, differ in essential aspects. Firstly, the very short time taken in the construction is notable and also the great accuracy of calculation of many of its features. For instance, the sphericity of the earth has been taken into account, in determining the span between the axes of the towers, at the top and bottom parts of these. A multicellular box, used for the foundation of the towers is of great interest. This has made it possible to reach the solid ground, starting from an artificial island, with full stability and safety. This structure means an increase in existing bridge spans, and new possibilities arise. On the other hand, the problem of the total life of such a structure remains, especially in this case, since the cables and anchorage are situated in a highly corrosive environment, such as the air over the sea. One of the main artificers of this great work is the venerable Aurmann, from whom such rich experience and knowledge has been passed on to us.La entrada en servicio del nuevo puente Verrazano-Narrows, situado en la bocana del puerto de Nueva York, ha constituido un resonante éxito para la ingeniería civil. Aunque la luz del Golden Gate es muy similar a la de esta obra, los métodos constructivos y no pocos detalles difieren esencialmente. Resalta en primer lugar el reducido período de tiempo empleado en la ejecución y el derroche de precisiones en cada una de sus partes, entre ellas el considerar la esfericidad terrestre para determinar la luz entre ejes de torres en la parte superior e inferior de las mismas. Constituye notable interés el cajón multicelular empleado para cimientos de las torres, que ha permitido llegar al firme, partiendo de un islote artificial

  16. Forecasting Kp from solar wind data: input parameter study using 3-hour averages and 3-hour range values

    Directory of Open Access Journals (Sweden)

    Wintoft Peter

    2017-01-01

    Full Text Available We have developed neural network models that predict Kp from upstream solar wind data. We study the importance of various input parameters, starting with the magnetic component Bz, particle density n, and velocity V and then adding total field B and the By component. As we also notice a seasonal and UT variation in average Kp we include functions of day-of-year and UT. Finally, as Kp is a global representation of the maximum range of geomagnetic variation over 3-hour UT intervals we conclude that sudden changes in the solar wind can have a big effect on Kp, even though it is a 3-hour value. Therefore, 3-hour solar wind averages will not always appropriately represent the solar wind condition, and we introduce 3-hour maxima and minima values to some degree address this problem. We find that introducing total field B and 3-hour maxima and minima, derived from 1-minute solar wind data, have a great influence on the performance. Due to the low number of samples for high Kp values there can be considerable variation in predicted Kp for different networks with similar validation errors. We address this issue by using an ensemble of networks from which we use the median predicted Kp. The models (ensemble of networks provide prediction lead times in the range 20–90 min given by the time it takes a solar wind structure to travel from L1 to Earth. Two models are implemented that can be run with real time data: (1 IRF-Kp-2017-h3 uses the 3-hour averages of the solar wind data and (2 IRF-Kp-2017 uses in addition to the averages, also the minima and maxima values. The IRF-Kp-2017 model has RMS error of 0.55 and linear correlation of 0.92 based on an independent test set with final Kp covering 2 years using ACE Level 2 data. The IRF-Kp-2017-h3 model has RMSE = 0.63 and correlation = 0.89. We also explore the errors when tested on another two-year period with real-time ACE data which gives RMSE = 0.59 for IRF-Kp-2017 and RMSE = 0.73 for IRF

  17. Forecasting Kp from solar wind data: input parameter study using 3-hour averages and 3-hour range values

    Science.gov (United States)

    Wintoft, Peter; Wik, Magnus; Matzka, Jürgen; Shprits, Yuri

    2017-11-01

    We have developed neural network models that predict Kp from upstream solar wind data. We study the importance of various input parameters, starting with the magnetic component Bz, particle density n, and velocity V and then adding total field B and the By component. As we also notice a seasonal and UT variation in average Kp we include functions of day-of-year and UT. Finally, as Kp is a global representation of the maximum range of geomagnetic variation over 3-hour UT intervals we conclude that sudden changes in the solar wind can have a big effect on Kp, even though it is a 3-hour value. Therefore, 3-hour solar wind averages will not always appropriately represent the solar wind condition, and we introduce 3-hour maxima and minima values to some degree address this problem. We find that introducing total field B and 3-hour maxima and minima, derived from 1-minute solar wind data, have a great influence on the performance. Due to the low number of samples for high Kp values there can be considerable variation in predicted Kp for different networks with similar validation errors. We address this issue by using an ensemble of networks from which we use the median predicted Kp. The models (ensemble of networks) provide prediction lead times in the range 20-90 min given by the time it takes a solar wind structure to travel from L1 to Earth. Two models are implemented that can be run with real time data: (1) IRF-Kp-2017-h3 uses the 3-hour averages of the solar wind data and (2) IRF-Kp-2017 uses in addition to the averages, also the minima and maxima values. The IRF-Kp-2017 model has RMS error of 0.55 and linear correlation of 0.92 based on an independent test set with final Kp covering 2 years using ACE Level 2 data. The IRF-Kp-2017-h3 model has RMSE = 0.63 and correlation = 0.89. We also explore the errors when tested on another two-year period with real-time ACE data which gives RMSE = 0.59 for IRF-Kp-2017 and RMSE = 0.73 for IRF-Kp-2017-h3. The errors as function

  18. Solar Heating and Cooling

    Science.gov (United States)

    Duffie, John A.; Beckman, William A.

    1976-01-01

    Describes recent research that has made solar energy economically competitive with other energy sources. Includes solar energy building architecture, storage systems, and economic production data. (MLH)

  19. Mobile Solar Tracker Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NIST's mobile solar tracking facility is used to characterize the electrical performance of photovoltaic panels. It incorporates meteorological instruments, a solar...

  20. Solar Energy Systems

    Science.gov (United States)

    1984-01-01

    Calibrated in kilowatt hours per square meter, the solar counter produced by Dodge Products, Inc. provides a numerical count of the solar energy that has accumulated on a surface. Solar energy sensing, measuring and recording devices in corporate solar cell technology developed by Lewis Research Center. Customers for their various devices include architects, engineers and others engaged in construction and operation of solar energy facilities; manufacturers of solar systems or solar related products, such as glare reducing windows; and solar energy planners in federal and state government agencies.

  1. Fast Solar Sailing for Solar System Exploration

    Data.gov (United States)

    National Aeronautics and Space Administration — Practical spinning solar sails will be needed for the most demanding and scientifically compelling solar sail missions of the future. The "heliogyro" is potentially...

  2. Polymethylmethacrylate-based luminescent solar concentrators with bottom-mounted solar cells

    International Nuclear Information System (INIS)

    Zhang, Yi; Sun, Song; Kang, Rui; Zhang, Jun; Zhang, Ningning; Yan, Wenhao; Xie, Wei; Ding, Jianjun; Bao, Jun; Gao, Chen

    2015-01-01

    Graphical abstract: - Highlights: • Bottom-mounted luminescent solar concentrators on dye-doped plates were studied. • The mechanism of transport process was proposed. • The fabricated luminescent solar concentrator achieved a gain of 1.38. • Power conversion efficiency of 5.03% was obtained with cell area coverage of 27%. • The lowest cost per watt of $1.89 was optimized with cell area coverage of 18%. - Abstract: Luminescent solar concentrators offer an attractive approach to concentrate sunlight economically without tracking, but the narrow absorption band of luminescent materials hinders their further development. This paper describes bottom-mounted luminescent solar concentrators on dye-doped polymethylmethacrylate plates that absorb not only the waveguided light but also the transmitted sunlight and partial fluorescent light in the escape cone. A series of bottom-mounted luminescent solar concentrators with size of 78 mm × 78 mm × 7 mm were fabricated and their gain and power conversion efficiency were investigated. The transport process of the waveguided light and the relationship between the bottom-mounted cells were studied to optimize the performance of the device. The bottom-mounted luminescent solar concentrator with cell area coverage of 9% displayed a cell gain of 1.38, to our best knowledge, which is the highest value for dye-doped polymethylmethacrylate plate luminescent solar concentrators. Power conversion efficiency as high as 5.03% was obtained with cell area coverage of 27%. Furthermore, the bottom-mounted luminescent solar concentrator was found to have a lowest cost per watt of $1.89 with cell area coverage of 18%. These results suggested that the fabricated bottom-mounted luminescent solar concentrator may have a potential in low-cost building integrated photovoltaic application

  3. On the production of narrow q2antiq2

    International Nuclear Information System (INIS)

    Hoffman, H.J.

    1978-01-01

    A rather detailed prediction of the mass spectrum and decay modes of Baryonium (or alternatively - diquonium) states has been proposed. The Baryonium in this approach is pictured as a diquark and an antidiquark bound by a short range force but separated by high angular momentum (L approximately or >1). Color plays a crucial role in the procedure, leading to the emergence of two distinct types of qq anti q anti q resonances. One kind has the qq (anti q anti q) pair in colour anti 3 (3) representation and hence consists of broad states decaying primarily into anti B B (T(True)-diquonium). The other type arises when the relevant color representation is 6(anti 6) which means that decay into anti B B must be suppressed if color is to be confined (M(Mock)-diquonium). Both qq anti q anti q classes are expected to decay only reluctantly into mesons as a result of the angular momentum barrier, an argument which derives its main support from the Dual Unitarisation scheme. Experimentally, this means that M-diquoniums should be rather easily detectable objects as they are distinguished by their narrowness on the one hand and their cascade decay mode on the other. The primary aim here is to elaborate on the production mechanisms for the various trajectories, using these to get some estimates of the cross-sections involved. (author)

  4. Free convection frost growth in a narrow vertical channel

    Energy Technology Data Exchange (ETDEWEB)

    Tanda, G.; Fossa, M. [Dipartimento di Ingegneria della Produzione, Termoenergetica e Modelli Matematici (DIPTEM), Universita degli Studi di Genova, via all' Opera Pia 15a, I-16145 Genova (Italy)

    2006-06-15

    Processes involving heat transfer from a humid air stream to a cold plate, with simultaneous deposition of frost, are of great importance in a variety of refrigeration equipment. In this work, frost growth on a vertical plate in free convection has been experimentally investigated. The cold plate (0.095m high, 0.282m wide) was placed in a narrow (2.395m high, 0.01m deep) vertical channel open at the top and bottom in order to permit the natural circulation of ambient air. The cold plate temperature and the air relative humidity were varied in the -40 to -4{sup o}C and 31-85% range, respectively, with the air temperature held fixed at 27{sup o}C (+/-1{sup o}C). The main quantities (thickness, temperature and mass of frost, heat flux at the cold plate), measured during the time evolution of the process, are presented as functions of the input parameters (relative humidity and cold plate temperature); in particular, the role exerted by the plate confinement on the frost growth is discussed. Data are recast in order to identify compact parameters able to correlate with good accuracy frost thickness, mass and density data. (author)

  5. Entanglement, excitations, and correlation effects in narrow zigzag graphene nanoribbons

    Science.gov (United States)

    Hagymási, I.; Legeza, Ö.

    2016-10-01

    We investigate the low-lying excitation spectrum and ground-state properties of narrow graphene nanoribbons with zigzag edge configurations. Nanoribbons of comparable widths have been synthesized very recently [P. Ruffieux et al., Nature (London) 531, 489 (2016)], 10.1038/nature17151, and their descriptions require more sophisticated methods since in this regime conventional methods, like mean-field or density-functional theory with local-density approximation, fail to capture the enhanced quantum fluctuations. Using the unbiased density-matrix renormalization-group algorithm, we calculate the charge gaps with high accuracy for different widths and interaction strengths and compare them with mean-field results. It turns out that the gaps are much smaller in the former case due to the proper treatment of quantum fluctuations. Applying the elements of quantum information theory, we also reveal the entanglement structure inside a ribbon and examine the spectrum of subsystem density matrices to understand the origin of entanglement. We examine the possibility of magnetic ordering and the effect of magnetic field. Our findings are relevant for understanding the gap values in different recent experiments and the deviations between them.

  6. Narrower bottlenecks could be more efficient for concentrating choanoflagellates

    Science.gov (United States)

    Sparacino, J.; Miño, G.; Koehl, M. A. R.; King, N.; Stocker, R.; Banchio, A. J.; Marconi, V. I.

    2015-11-01

    In evolutionary biology choanoflagellates are broadly investigated as the closest living relatives of the animal ancestors. Under diverse environmental cues, choanoflagellate Salpingoeca rosetta can differentiate in two types of solitary swimming cells: slow and fast microswimmers. Here we present a first phenomenological 2D-model for the choanoflagellates dynamics confined into a flat device divided by a wall of asymmetric microconstrictions. The model allow us to optimize the geometry of the microchannels for directing and concentrating cell populations under strict control. We solve our set of dynamical equations using Langevin dynamics. Experimental parameters for the motility of the slow and fast cells were measured and used for our numerical estimations of the directed transport efficiency, otherwise we have no adjustable parameters. We find remarkable differences in the rectification results for slow and fast choanoflagellates, which give us a strategy to develop a suitable microfluidic sorting device. For a given population velocity, narrower bottlenecks, of similar size to the cell dimension, show to be more efficient as concentrator of populations. Experiments and simulations are in good agreement.

  7. Voicing Strategies Employed in Narrow Listening Among Iranian Female Freshmen

    Directory of Open Access Journals (Sweden)

    Mohsen Shahrokhi

    2013-05-01

    Full Text Available This study discusses the findings of a qualitative study on the strategies used by Iranian female freshmen in narrow listening. The data collected through semi-structured interview with 12 female freshmen (four learners as  advanced, four as intermediate and four as low chosen purposefully based on their scores in the Oxford Placement Test administered. Six out of 12 freshmen were identified for the think-aloud protocol to draw out the strategies they used. The data collected were analyzed using open, axial, and selective-coding. The analysis of the participants’ interview and think-aloud protocol data generated 12 major themes. Five themes (attention, readiness, evaluating, autonomous learning, and change the speech rate described meta-cognitive; five themes (imitating and repeating, references, visualization, making notes while listening and word-by-word and sentence-by-sentence attention described cognitive strategies and two themes (asking for help, self-talk described socio-affective strategies. These strategies need to be taught explicitly to increase learners’ understanding of the spoken texts in the second/foreign language. This study recommends that Iranian EFL female freshman university learners’ top-down, bottom-up processing and listening strategy awareness should be cultivated and integrated into the teaching of listening to improve the learners’ listening ability.

  8. Prosodic Marking of Narrow Focus in Seoul Korean

    Directory of Open Access Journals (Sweden)

    Hae-Sung Jeon

    2017-01-01

    Full Text Available This paper explores prosodic marking of narrow (corrective focus in Seoul Korean. Korean lacks lexical stress and it has a phonologized association between the Accentual Phrase (AP initial segment and intonation. In the experiment, 4 speakers read sentences including a two-item list which were designed to elicit either an L or H AP-initial tone. The durational variations, the pitch events at prosodic boundaries, and 'F''0 'span in 32 sentences read neutrally and 64 sentences read with one of the items under focus were analyzed. The results show that the focused constituent consistently initiates a new prosodic phrase. In comparison to the neutrally spoken or defocused counterpart, the focused constituent was more likely to be realized as an Intonational Phrase (IP in some contexts. Bitonal IP boundary tones were more likely to occur under focus than monotonal tones. In addition, in focused constituents, durational expansion particularly at the phrase-edges, expansion in 'F''0 'span, and raising of the phrase-initial pitch were observed. On the other hand, defocused constituents were not phonetically reduced compared to the neutral counterparts. The results imply that the phonetic cues spreading over the focused constituent complement the exaggerated prosodic boundaries.

  9. TESTING DIFFERENT SURVEY TECHNIQUES TO MODEL ARCHITECTONIC NARROW SPACES

    Directory of Open Access Journals (Sweden)

    A. Mandelli

    2017-08-01

    Full Text Available In the architectural survey field, there has been the spread of a vast number of automated techniques. However, it is important to underline the gap that exists between the technical specification sheet of a particular instrument and its usability, accuracy and level of automation reachable in real cases scenario, especially speaking about Cultural Heritage (CH field. In fact, even if the technical specifications (range, accuracy and field of view are known for each instrument, their functioning and features are influenced by the environment, shape and materials of the object. The results depend more on how techniques are employed than the nominal specifications of the instruments. The aim of this article is to evaluate the real usability, for the 1:50 architectonic restitution scale, of common and not so common survey techniques applied to the complex scenario of dark, intricate and narrow spaces such as service areas, corridors and stairs of Milan’s cathedral indoors. Tests have shown that the quality of the results is strongly affected by side-issues like the impossibility of following the theoretical ideal methodology when survey such spaces. The tested instruments are: the laser scanner Leica C10, the GeoSLAM ZEB1, the DOT DPI 8 and two photogrammetric setups, a full frame camera with a fisheye lens and the NCTech iSTAR, a panoramic camera. Each instrument presents advantages and limits concerning both the sensors themselves and the acquisition phase.

  10. Clinical outcome of narrow diameter implants inserted into allografts

    Directory of Open Access Journals (Sweden)

    Maurizio Franco

    2009-08-01

    Full Text Available OBJECTIVE: Narrow diameter implants (NDI (i.e. diameter <3.75 mm are a potential solution for specific clinical situations, such as reduced interradicular bone, thin alveolar crest and replacement of teeth with small cervical diameter. NDI have been available in clinical practice since the 1990s, but only few studies have analyzed their clinical outcome and no study have investigated NDI inserted in fresh-frozen bone (FFB grafts. Thus, a retrospective study on a series of NDI placed in homologue FFB was designed to evaluate their clinical outcome. MATERIAL AND METHODS: In the period between December 2003 and December 2006, 36 patients (22 females and 14 males, mean age 53 years with FFB grafts were selected and 94 different NDI were inserted. The mean follow-up was 25 months. To evaluate the effect of several host-, surgery-, and implant-related factors, marginal bone loss (MBL was considered an indicator of success rate (SCR. The Kaplan Meier algorithm and Cox regression were used. RESULTS: Only 5 out of 94 implants were lost (i.e. survival rate - SVR 95.7% and no differences were detected among the studied variables. On the contrary, the Cox regression showed that the graft site (i.e. maxilla reduced MBL. CONCLUSIONS: NDI inserted in FFB have a high SVR and SCR similar to those reported in previous studies on regular and NDI inserted in non-grafted jaws. Homologue FFB is a valuable material in the insertion of NDI.

  11. The Use of Narrow Diameter Implants in the Molar Area

    Directory of Open Access Journals (Sweden)

    M. Saad

    2016-01-01

    Full Text Available Implant rehabilitations in the posterior jaw are influenced by many factors such as the condition of the remaining teeth, the force factors related to the patient, the quality of the bone, the maintenance of the hygiene, the limited bone height, the type and extent of edentulism, and the nature of the opposing arch. The gold standard is to place a regular diameter implant (>3.7 mm or a wide one to replace every missing molar. Unfortunately, due to horizontal bone resorption, this option is not possible without lateral bone augmentation. In this situation, narrow diameter implant (NDI < 3.5 mm could be the alternative to lateral bone augmentation procedures. This paper presents a clinical study where NDIs were used for the replacement of missing molars. They were followed up to 11 years. Special considerations were observed and many parameters were evaluated. NDI could be used to replace missing molar in case of moderate horizontal bone resorption if strict guidelines are respected. Yet, future controlled prospective clinical trials are required to admit their use as scientific evidence.

  12. A narrow quasi-bound state of the DNN system

    International Nuclear Information System (INIS)

    Doté, A.; Bayar, M.; Xiao, C.W.; Hyodo, T.; Oka, M.; Oset, E.

    2013-01-01

    We have investigated a charmed system of DNN (composed of two nucleons and a D meson) by a complementary study with a variational calculation and a Faddeev calculation with fixed-center approximation (Faddeev-FCA). In the present study, we employ a DN potential based on a vector–meson exchange picture in which a resonant Λ c (2595) is dynamically generated as a DN quasi-bound state, similarly to the Λ(1405) as a K ¯ N one in the strange sector. As a result of the study of variational calculation with an effective DN potential and three kinds of NN potentials, the DNN(J π =0 − ,I=1/2) is found to be a narrow quasi-bound state below Λ c (2595)N threshold: total binding energy ∼225 MeV and mesonic decay width ∼25 MeV. On the other hand, the J π =1 − state is considered to be a scattering state of Λ c (2595) and a nucleon. These results are essentially supported by the Faddeev-FCA calculation. By the analysis of the variational wave function, we have found a unique structure in the DNN(J π =0 − ,I=1/2) such that the D meson stays around the center of the total system due to the heaviness of the D meson

  13. Assembly auxiliary system for narrow cabins of spacecraft

    Science.gov (United States)

    Liu, Yi; Li, Shiqi; Wang, Junfeng

    2015-09-01

    Due to the narrow space and complex structure of spacecraft cabin, the existing asssembly systems can not well suit for the assembly process of cabin products. This paper aims to introduce an assembly auxiliary system for cabin products. A hierarchical-classification method is proposed to re-adjust the initial assembly relationship of cabin into a new hierarchical structure for efficient assembly planning. An improved ant colony algorithm based on three assembly principles is established for searching a optimizational assembly sequence of cabin parts. A mixed reality assembly environment is constructed with enhanced information to promote interaction efficiency of assembly training and guidance. Based on the machine vision technology, the inspection of left redundant objects and measurement of parts distance in inner cabin are efficiently performed. The proposed system has been applied to the assembly work of a spacecraft cabin with 107 parts, which includes cabin assembly planning, assembly training and assembly quality inspection. The application result indicates that the proposed system can be an effective assistant tool to cabin assembly works and provide an intuitive and real assembly experience for workers. This paper presents an assembly auxiliary system for spacecraft cabin products, which can provide technical support to the spacecraft cabin assembly industry.

  14. Electronically steerable ultrasound-driven long narrow air stream

    Science.gov (United States)

    Hasegawa, Keisuke; Qiu, Liwei; Noda, Akihito; Inoue, Seki; Shinoda, Hiroyuki

    2017-08-01

    Acoustic streaming, which is the unidirectional movement of a medium driven by its internal intense acoustic vibrations, has been known for more than a century. Despite the long history of research, there have been no scientific reports on the creation of long stretching steerable airflows in an open space, generated by ultrasound. Here, we demonstrated the creation of a narrow, straight flow in air to a distance of 400 mm from an ultrasound phased array emitting a Bessel beam. We also demonstrated that the direction of the flow could be controlled by appropriately tuning the wavefronts of the emission from the phased array. Unlike conventional airflows such as those generated by jets or fans, which decelerate and spread out as they travel farther, the flow that we created proceeded while being accelerated by the kinetic energy supplied from the ultrasound beam and keeping the diameter as small as the wavelength. A flow of 3 m/s with a 10 mm diameter extended for several hundreds of millimeters in a room that was large enough to be regarded as an open-boundary environment. These properties of the generated flow will enable fine and rapid control of three-dimensional airflow distributions.

  15. Narrow-line laser cooling by adiabatic transfer

    Science.gov (United States)

    Norcia, Matthew A.; Cline, Julia R. K.; Bartolotta, John P.; Holland, Murray J.; Thompson, James K.

    2018-02-01

    We propose and demonstrate a novel laser cooling mechanism applicable to particles with narrow-linewidth optical transitions. By sweeping the frequency of counter-propagating laser beams in a sawtooth manner, we cause adiabatic transfer back and forth between the ground state and a long-lived optically excited state. The time-ordering of these adiabatic transfers is determined by Doppler shifts, which ensures that the associated photon recoils are in the opposite direction to the particle’s motion. This ultimately leads to a robust cooling mechanism capable of exerting large forces via a weak transition and with reduced reliance on spontaneous emission. We present a simple intuitive model for the resulting frictional force, and directly demonstrate its efficacy for increasing the total phase-space density of an atomic ensemble. We rely on both simulation and experimental studies using the 7.5 kHz linewidth 1S0 to 3P1 transition in 88Sr. The reduced reliance on spontaneous emission may allow this adiabatic sweep method to be a useful tool for cooling particles that lack closed cycling transitions, such as molecules.

  16. Testing Different Survey Techniques to Model Architectonic Narrow Spaces

    Science.gov (United States)

    Mandelli, A.; Fassi, F.; Perfetti, L.; Polari, C.

    2017-08-01

    In the architectural survey field, there has been the spread of a vast number of automated techniques. However, it is important to underline the gap that exists between the technical specification sheet of a particular instrument and its usability, accuracy and level of automation reachable in real cases scenario, especially speaking about Cultural Heritage (CH) field. In fact, even if the technical specifications (range, accuracy and field of view) are known for each instrument, their functioning and features are influenced by the environment, shape and materials of the object. The results depend more on how techniques are employed than the nominal specifications of the instruments. The aim of this article is to evaluate the real usability, for the 1:50 architectonic restitution scale, of common and not so common survey techniques applied to the complex scenario of dark, intricate and narrow spaces such as service areas, corridors and stairs of Milan's cathedral indoors. Tests have shown that the quality of the results is strongly affected by side-issues like the impossibility of following the theoretical ideal methodology when survey such spaces. The tested instruments are: the laser scanner Leica C10, the GeoSLAM ZEB1, the DOT DPI 8 and two photogrammetric setups, a full frame camera with a fisheye lens and the NCTech iSTAR, a panoramic camera. Each instrument presents advantages and limits concerning both the sensors themselves and the acquisition phase.

  17. Differentiating phase shift and delay in narrow band coherent signals.

    Science.gov (United States)

    Muthuraman, M; Govindan, R B; Deuschl, G; Heute, U; Raethjen, J

    2008-05-01

    Differentiating between a fixed activation pattern (phase shift) and conduction time (time delay) in rhythmic signals has important physiological implications but is methodologically difficult. Delay was estimated by the maximising coherence method and phase spectra calculated between (i) a narrow band-pass filtered AR2 process and its delayed copy for different phase shifts, (ii) the surface EMGs from two antagonistic forearm muscles with reciprocal alternating activity, and (iii) EEG and EMG data from 11 recordings in five Parkinsonian tremor patients. Estimated delays between the versions of the AR2 process resembled the real delay and were not significantly biased by the phase-shifts. The reciprocal alternating pattern of muscle activation was shown to be a pure phase-shift without any time delay. The phase between tremor-coherent cortical electrodes and EMG showed opposite signs and differed by 3pi/4-pi between the antagonistic muscles. Bidirectional delays between contralateral cortex and EMG did not differ between the antagonists and were in keeping with fast corticospinal transmission and feedback to the cortex for both muscles. Phase shifts and delays reflect different mechanisms in tremor related oscillatory interactions. The maximising coherence method can differentiate between them.

  18. IP-based narrow-band videophone system

    Science.gov (United States)

    Zhang, Zhengbing; Zhu, Dongmei; Xue, Liang; Zhu, Guangxi

    2005-02-01

    Architecture of an IP-based narrow-band videophone system is proposed in this paper for convenient videophone calls between any two computers even if being placed in two different LANs within network agents. The bandwidth need of each call is less than 256 kbps. The system consists of two kinds of entities: Videophone Terminals (VPT) and a Video Call Server (VCS). A VPT is actually a microcomputer program, composed of 4 primary parts, an audio codec, a video codec, a media deliverer/receiver and a call controller. The basic functions of the VCS include videophone number generation and management, access admission and address resolution. The VCS with a public IP address plays an important role in the system especially when a video call has to penetrate through network agents. Each VPT in the system gets its own external transport address from the VCS through registration process. A calling VPT would receive the external transport address of the called VPT from the VCS through address resolution. The proposed system works and is helpful to accelerate the realization of people's videophone dream over IP networks.

  19. Numerical Simulation for Mechanism of Airway Narrowing in Asthma

    Science.gov (United States)

    Bando, Kiyoshi; Yamashita, Daisuke; Ohba, Kenkichi

    A calculation model is proposed to examine the generation mechanism of the numerous lobes on the inner-wall of the airway in asthmatic patients and to clarify luminal occlusion of the airway inducing breathing difficulties. The basement membrane in the airway wall is modeled as a two-dimensional thin-walled shell having inertia force due to the mass, and the smooth muscle contraction effect is replaced by uniform transmural pressure applied to the basement membrane. A dynamic explicit finite element method is used as a numerical simulation method. To examine the validity of the present model, simulation of an asthma attack is performed. The number of lobes generated in the basement membrane increases when transmural pressure is applied in a shorter time period. When the remodeling of the basement membrane occurs characterized by thickening and hardening, it is demonstrated that the number of lobes decreases and the narrowing of the airway lumen becomes severe. Comparison of the results calculated by the present model with those measured for animal experiments of asthma will be possible.

  20. Multimodal transport and dispersion of organelles in narrow tubular cells

    Science.gov (United States)

    Mogre, Saurabh S.; Koslover, Elena F.

    2018-04-01

    Intracellular components explore the cytoplasm via active motor-driven transport in conjunction with passive diffusion. We model the motion of organelles in narrow tubular cells using analytical techniques and numerical simulations to study the efficiency of different transport modes in achieving various cellular objectives. Our model describes length and time scales over which each transport mode dominates organelle motion, along with various metrics to quantify exploration of intracellular space. For organelles that search for a specific target, we obtain the average capture time for given transport parameters and show that diffusion and active motion contribute to target capture in the biologically relevant regime. Because many organelles have been found to tether to microtubules when not engaged in active motion, we study the interplay between immobilization due to tethering and increased probability of active transport. We derive parameter-dependent conditions under which tethering enhances long-range transport and improves the target capture time. These results shed light on the optimization of intracellular transport machinery and provide experimentally testable predictions for the effects of transport regulation mechanisms such as tethering.

  1. Structural properties of hard disks in a narrow tube

    International Nuclear Information System (INIS)

    Varga, S; Gurin, P; Balló, G

    2011-01-01

    Positional ordering of a two-dimensional fluid of hard disks is examined in tubes so narrow that only nearest neighbor interactions take place. Using the exact transfer-matrix method the transverse and longitudinal pressure components and the correlation function are determined numerically. Fluid–solid phase transition does not occur even in the widest tube, where the method just loses its exactness, but the appearance of a dramatic change in the equation of state and the longitudinal correlation function shows that the system undergoes a structural change from a fluid to a solid-like order. The pressure components show that the collisions are dominantly longitudinal at low densities, while they are transverse in the vicinity of the close packing density. The transverse correlation function shows that the size of solid-like domains grows exponentially with increasing pressure and the correlation length diverges at close packing. It is possible to find an analytically solvable model by expanding the contact distance up to first order. The approximate model, which corresponds to a system of hard parallel rhombuses, behaves very similarly to the system of hard disks

  2. Narrow nuclear resonance profiling of Al with subnanometric depth resolution

    International Nuclear Information System (INIS)

    Rosa, E.B.O. da; Krug, C.; Stedile, F.C.; Morais, J.; Baumvol, I.J.R.

    2002-01-01

    We report on the use of the narrow and isolated resonance at 404.9 keV in the cross-section curve of the 27 Al(p,γ) 28 Si nuclear reaction for profiling Al in ultrathin aluminum oxide films on Si. The samples were characterized as-deposited and after thermal annealing, so that Al transport could be studied. An estimated depth resolution of approximately 0.4 nm near the surface of the films could be obtained owing to: (i) the very small resonance width; (ii) the high stopping power of Al 2 O 3 for 404.9 keV protons; (iii) the high energy stability of the proton beam provided by the 500 kV HVEE ion implanter at Porto Alegre; and (iv) an apparent thickness magnification by a factor between 2.0 and 2.4 with the use of glancing incidence. This technique is compared to other methods for Al profiling like medium energy ion scattering and some sputtering-based techniques

  3. Narrow band vacuum ultraviolet radiation, produced by fast conical discharge

    Science.gov (United States)

    Antsiferov, P. S.; Dorokhin, L. A.; Koshelev, K. N.

    2018-04-01

    The article presents the experimental study of discharges in a conical cavity, filled with Ar at pressure 80 Pa. The electrical current driver (inductive storage with plasma erosion opening switch) supplies to the load electrical current pulse with growth rate about 1012 A s‑1 and maximal value 30–40 kA. The convergent conical shock wave starts from the inner surface of the discharge cavity and collapses in ‘zippering’ mode. The pin hole camera imaging with MCP detector (time resolution 5 ns) have demonstrated the appearance of effectively fast moving compact plasma with visible velocity v  =  (1.5  ±  0.14)  ×  107 cm s‑1. Plasma emits narrow band radiation in the spectral range of Rydberg series transitions of Ar VII, Ar VIII with quantum number up to n  =  9 (wavelength about 11 nm). The intensity of radiation is comparable with the total plasma emission in the range 10–50 nm. Charge exchange between multiply charged Ar ions and cold Ar atoms of working gas is proposed as the possible mechanism of the origin of the radiation.

  4. 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

  5. Solar energy an introduction

    CERN Document Server

    Mackay, Michael E

    2015-01-01

    Solar Energy presents an introduction to all aspects of solar energy, from photovoltaic devices to active and passive solar thermal energy conversion, giving both a detailed and broad perspective of the field. It is aimed at the beginner involved in solar energy or a related field, or for someone wanting to gain a broader perspective of solar energy technologies. A chapter considering solar radiation, basic principles applied to solar energy, semiconductor physics, and light absorption brings the reader on equal footing with the technology of either solar generated electrical current or useful heat. Details of how a solar cell works and then production of current from a photovoltaic device is discussed. Characterization of a solar cell is examined, allowing one the ability to interpret the current-voltage relation, followed by discussion of parameter extraction from this relation. This information can be used to understand what limits the performance of a given solar cell with the potential to optimize its pe...

  6. Reconstruction of total solar irradiance 1974-2009

    Science.gov (United States)

    Ball, W. T.; Unruh, Y. C.; Krivova, N. A.; Solanki, S.; Wenzler, T.; Mortlock, D. J.; Jaffe, A. H.

    2012-05-01

    Context. The study of variations in total solar irradiance (TSI) is important for understanding how the Sun affects the Earth's climate. Aims: Full-disk continuum images and magnetograms are now available for three full solar cycles. We investigate how modelled TSI compares with direct observations by building a consistent modelled TSI dataset. The model, based only on changes in the photospheric magnetic flux can then be tested on rotational, cyclical and secular timescales. Methods: We use Kitt Peak and SoHO/MDI continuum images and magnetograms in the SATIRE-S model to reconstruct TSI over cycles 21-23. To maximise independence from TSI composites, SORCE/TIM TSI data are used to fix the one free parameter of the model. We compare and combine the separate data sources for the model to estimate an uncertainty on the reconstruction and prevent any additional free parameters entering the model. Results: The reconstruction supports the PMOD composite as being the best historical record of TSI observations, although on timescales of the solar rotation the IRMB composite provides somewhat better agreement. Further to this, the model is able to account for 92% of TSI variations from 1978 to 2009 in the PMOD composite and over 96% during cycle 23. The reconstruction also displays an inter-cycle, secular decline of 0.20+0.12-0.09 W m-2 between cycle 23 minima, in agreement with the PMOD composite. Conclusions: SATIRE-S is able to recreate TSI observations on all timescales of a day and longer over 31 years from 1978. This is strong evidence that changes in photospheric magnetic flux alone are responsible for almost all solar irradiance variations over the last three solar cycles.

  7. A new method for forecasting the solar cycle descent time

    Directory of Open Access Journals (Sweden)

    Kakad Bharati

    2015-01-01

    Full Text Available The prediction of an extended solar minimum is extremely important because of the severity of its impact on the near-earth space. Here, we present a new method for predicting the descent time of the forthcoming solar cycle (SC; the method is based on the estimation of the Shannon entropy. We use the daily and monthly smoothed international sunspot number. For each nth SC, we compute the parameter [Tpre]n by using information on the descent and ascent times of the n − 3th and nth SCs, respectively. We find that [Tpre] of nth SC and entropy can be effectively used to predict the descent time of the n + 2th SC. The correlation coefficient between [Td]n+2 − [Tpre]n and [E]n is found to be 0.95. Using these parameters the prediction model is developed. Solar magnetic field and F10.7 flux data are available for SCs 21–22 and 19–23, respectively, and they are also utilized to get estimates of the Shannon entropy. It is found that the Shannon entropy, a measure of randomness inherent in the SC, is reflected well in the various proxies of the solar activity (viz sunspot, magnetic field, F10.7 flux. The applicability and accuracy of the prediction model equation is verified by way of association of least entropy values with the Dalton minimum. The prediction model equation also provides possible criteria for the occurrence of unusually longer solar minima.

  8. EDITORIAL Solar harvest Solar harvest

    Science.gov (United States)

    Demming, Anna

    2010-12-01

    The first observations of the photoelectric effect date back to the early 19th century from work by Alexandre Edmond Becquerel, Heinrich Hertz, Wilhelm Hallwachs and J J Thomson. The theory behind the phenomena was clarified in a seminal paper by Einstein in 1905 and became an archetypical feature of the wave-particle description of light. A different manifestation of quantised electron excitation, whereby electrons are not emitted but excited into the valence band of the material, is what we call the photoconductive effect. As well as providing an extension to theories in fundamental physics, the phenomenon has spawned a field with enormous ramifications in the energy industry through the development of solar cells. Among advances in photovoltaic technology has been the development of organic photovoltaic technology. These devices have many benefits over their inorganic counterparts, such as light-weight, flexible material properties, as well as versatile materials' synthesis and low-cost large-scale production—all highly advantageous for manufacturing. The first organic photovoltaic systems were reported over 50 years ago [1], but the potential of the field has escalated in recent years in terms of efficiency, largely through band offsetting. Since then, great progress has been made in studies for optimising the efficiency of organic solar cells, such as the work by researchers in Germany and the Netherlands, where investigations were made into the percentage composition and annealing effects on composites of poly(3-hexylthiophene) (P3HT) and the fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) [2]. Hybrid devices that aim to exploit the advantages of both inorganic and organic constituents have also proven promising. One example of this is the work reported by researchers in Tunisia and France on a systematic study for optimising the composition morphology of TiO2 nanoparticles in poly(N-vinylcarbazole) (PVK), which also led to insights

  9. Solar flares

    International Nuclear Information System (INIS)

    Zirin, H.

    1974-01-01

    A review of the knowledge about solar flares which has been obtained through observations from the earth and from space by various methods is presented. High-resolution cinematography is best carried out at H-alpha wavelengths to reveal the structure, time history, and location of flares. The classification flares in H alpha according to either physical or morphological criteria is discussed. The study of flare morphology, which shows where, when, and how flares occur, is important for evaluating theories of flares. Consideration is given to studies of flares by optical spectroscopy, radio emissions, and at X-ray and XUV wavelengths. Research has shown where and possibly why flares occur, but the physics of the instability involved, of the particle acceleration, and of the heating are still not understood. (IAA)

  10. Applications of solar energy in industrial parks

    Energy Technology Data Exchange (ETDEWEB)

    Greaver, V.W.; Farrington, R.B.; Leboeuf, C.M.

    1980-05-01

    The four phases of ongoing work at SERI that examines many unresolved questions regarding the purpose, solar applicability, economics, and energy modeling of industral parks are presented. The first phase involved site visits to approximately 300 parks in 12 major metropolitan areas of 9 states. Phase 2 entails an analysis of four parks selected from those parks surveyed. Phase 3 narrows the focus to two parks to be examined for detailed technical and engineering analysis. Phase 4 incorporates all of the work of the earlier phases with economic criteria to produce an energy allocation model describing energy delivery and consumption within the park.

  11. Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation

    Science.gov (United States)

    Cliver, E. W.; Richardson, I. G.; Ling, A. G.

    2011-01-01

    In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift: at such times. In 2009, the approx.2 GV GCR intensity measured by the Newark neutron monitor increased by approx.5% relative to its maximum value two cycles earlier even though the average tilt angle in 2009 was slightly larger than that in 1986 (approx.20deg vs. approx.14deg), while solar wind B was significantly lower (approx.3.9 nT vs. approx.5.4 nT). A decomposition of the solar wind into high-speed streams, slow solar wind, and coronal mass ejections (CMEs; including postshock flows) reveals that the Sun transmits its message of changing magnetic field (diffusion coefficient) to the heliosphere primarily through CMEs at solar maximum and high-speed streams at solar minimum. Long-term reconstructions of solar wind B are in general agreement for the approx. 1900-present interval and can be used to reliably estimate GCR intensity over this period. For earlier epochs, however, a recent Be-10-based reconstruction covering the past approx. 10(exp 4) years shows nine abrupt and relatively short-lived drops of B to modulation of the local interstellar spectrum) at a given energy/rigidity. The 30-40% increase in the intensity of 2.5 GV electrons observed by Ulysses during the recent solar minimum raises an interesting paradox that will need to be resolved.

  12. Fundamental properties of solar-like oscillating stars from frequencies of minimum Δν - I. Model computations for solar composition

    Science.gov (United States)

    Yıldız, M.; Çelik Orhan, Z.; Aksoy, Ç.; Ok, S.

    2014-07-01

    Low amplitude is the defining characteristic of solar-like oscillations. The space projects Kepler and CoRoT give us a great opportunity to successfully detect such oscillations in numerous targets. Achievements of asteroseismology depend on new discoveries of connections between the oscillation frequencies and stellar properties. In the previous studies, the frequency of the maximum amplitude and the large separation between frequencies were used for this purpose. In the present study, we confirm that the large separation between the frequencies has two minima at two different frequency values. These are the signatures of the He II ionization zone, and as such have very strong diagnostic potential. We relate these minima to fundamental stellar properties such as mass, radius, luminosity, age and mass of convective zone. For mass, the relation is simply based on the ratio of the frequency of minimum Δν to the frequency of maximum amplitude. These frequency comparisons can be very precisely computed, and thus the mass and radius of a solar-like oscillating star can be determined to high precision. We also develop a new asteroseismic diagram which predicts structural and evolutionary properties of stars with such data. We derive expressions for mass, radius, effective temperature, luminosity and age in terms of purely asteroseismic quantities. For solar-like oscillating stars, we now will have five very important asteroseismic tools (two frequencies of minimum Δν, the frequency of maximum amplitude, and the large and small separations between the oscillation frequencies) to decipher properties of stellar interior astrophysics.

  13. Nontechnical Barriers to Solar Energy Use: Review of Recent Literature

    Energy Technology Data Exchange (ETDEWEB)

    Margolis, R.; Zuboy, J.

    2006-09-01

    This paper reviews the nontechnical barriers to solar energy use, drawing on recent literature to help identify key barriers that must be addressed as part of the Technology Acceptance efforts under the U.S. Department of Energy (DOE) Solar America Initiative. A broad literature search yielded more than 400 references, which were narrowed to 19 recent documents on nontechnical barriers to the use of solar energy and other energy efficiency and renewable energy (EE/RE) technologies. Some of the most frequently identified barriers included lack of government policy supporting EE/RE, lack of information dissemination and consumer awareness about energy and EE/RE, high cost of solar and other EE/RE technologies compared with conventional energy, and inadequate financing options for EE/RE projects.

  14. Procedure to the collapse of the Tacoma Narrows Bridge

    Science.gov (United States)

    Kim, Woojin; Choi, Heacheon

    2017-11-01

    The Tacoma Narrows Bridge (TNB) was collapsed in 1940 at the wind speed (U) of 18m/s corresponding to Re = 3000000 based on the height (H=2.4m) of the deck. The deck was lifted by two cables with 110 hangers and each cable was suspended by two towers. The deck experienced a vertical vibration with the spanwise wavelengths (l) of 1/4 and 1/4.5 of the deck length (L) and the non-dimensional frequency of St = fH/U = 0.08, followed by a torsional vibration with l = L and St = 0.027. We investigate the procedure before the collapse of the TNB using numerical simulation with fluid-structure interaction. We consider Re = 300 and 1000 because the non-dimensional frequency of vortex shedding is not much changed by the change in the Reynolds number due to a fixed separation point at the leading edge of the deck. A nonlinear model for a suspension bridge (Arioli & Gazzola, 2017) is used for the motion of the TNB. Initially, two-dimensional vortex shedding is generated with a weak vibration of the deck. Then, the deck oscillates vertically with l = L/4.5 and St = 0.09, together with three-dimensional vortical structures behind the deck. Finally, the deck oscillates torsionally with l = L and St = 0.033. These predicted vibrations of the TNB are in good agreements with those occurred in 1940. Supported by NRF-2016R1E1A1A02921549.

  15. Illegal "no prescription" internet access to narrow therapeutic index drugs.

    Science.gov (United States)

    Liang, Bryan A; Mackey, Tim K; Lovett, Kimberly M

    2013-05-01

    Narrow therapeutic index (NTI) drugs, because of proximity of therapeutic amounts to toxic amounts, require close professional oversight, particularly when switching formulations. However, safe use may be compromised by unsupervised switching through access to online "no prescription" Web sites. We assessed no prescription online availability of NTI drugs, using an academically published list (core NTI drugs). Using the Google search term "buy DRUG no prescription," we reviewed the first 5 search result pages for marketing of no prescription NTI drugs. We further assessed if National Association of Boards of Pharmacy (NABP) Not Recommended vendors were marketing NTI drugs. Searches were conducted from November 3, 2012 to January 3, 2013. For core NTI drugs, we found 13 of 14 NTI drugs (92%) marketed as available without prescription, all from NABP Not Recommended vendors. On the basis of these initial findings, we expanded our core list to 12 additional NTI drugs; 11 of 12 of these drugs (92%) were available from no prescription Web sites. Overall, 24 of 26 NTI drugs (92%) were illegally marketed as available online without the need for a prescription. Suspect online NTI drug access from no prescription vendors represents a significant patient safety risk because of potential patient drug switching and risk of counterfeit versions. Further, state health care exchanges with coverage limitations may drive patients to seek formulations online. Food and Drug Administration harmonization with tighter international NTI drug standards should be considered, and aggressive action against suspect online marketers should be a regulatory and public health priority. Copyright © 2013 Elsevier HS Journals, Inc. All rights reserved.

  16. Hull loss accident model for narrow body commercial aircraft

    Directory of Open Access Journals (Sweden)

    Somchanok Tiabtiamrat

    2010-10-01

    Full Text Available Accidents with narrow body aircraft were statistically evaluated covering six families of commercial aircraft includingBoeing B737, Airbus A320, McDonnell Douglas MD80, Tupolev TU134/TU154 and Antonov AN124. A risk indicator for eachflight phase was developed based on motion characteristics, duration time, and the presence of adverse weather conditions.The estimated risk levels based on these risk indicators then developed from the risk indicator. Regression analysis indicatedvery good agreement between the estimated risk level and the accident ratio of hull loss cases per number of delivered aircraft.The effect of time on the hull loss accident ratio per delivered aircraft was assessed for B737, A320 and MD80. Equationsrepresenting the effect of time on hull loss accident ratio per delivered aircraft were proposed for B737, A320, and MD80,while average values of hull loss accident ratio per delivered aircraft were found for TU134, TU154, and AN 124. Accidentprobability equations were then developed for each family of aircraft that the probability of an aircraft in a hull loss accidentcould be estimated for any aircraft family, flight phase, presence of adverse weather factor, hour of day, day of week, monthof year, pilot age, and pilot flight hour experience. A simplified relationship between estimated hull loss accident probabilityand unsafe acts by human was proposed. Numerical investigation of the relationship between unsafe acts by human andfatality ratio suggested that the fatality ratio in hull loss accident was dominated primarily by the flight phase media.

  17. The narrow-band imaging examination method in otorhinolaryngology

    Directory of Open Access Journals (Sweden)

    Robert Šifrer

    2013-10-01

    Full Text Available Early diagnostics could improve the prognosis of patients with squamous-cell carcinomas of the head and neck. Narrow-Band Imaging (NBI is the latest examination method in the group of biologic endoscopies. NBI improves the distinction between malignant and benign mucosal lesions. Early suspect oncologic lesions that may otherwise be missed by normal white light illumination can also be diagnosed. The biggest benefit of NBI technology is achieved by using it together with a HDTV camera that enables better contrast and higher resolution. NBI is based on better imaging of superficial mucosal vasculature. The biologic potential of mucosal lesions could be predicted from vascular changes. The colour of normal mucosa under NBI is blue and green and the vessels show no pathological features. Well-demarcated brownish areas and scattered thick dark spots and abnormal winding and branching out of vessels on the mucosa are all oncologically suspicious features. Authors report the experience from literature on the use of NBI to identify carcinomas of the oral cavity, epipharynx, oropharynx, hypopharynx and larynx and evaluation of unknown primaries. In addition, the literature reports the benefit of NBI in identifying early stage carcinomas in previously irradiated patients. Persistence and recurrence of carcinoma and the development of new primary tumour could easily be missed by using only standard white-light illumination. The method proved to be highly sensitive and specific for predicting malignant changes in the above-mentioned circumstances. Authors report their own experience with NBI technology as well. For further improvement of the method, new technologic development is expected to enable the connection of NBI and HDTV with flexible endoscopes.

  18. The propagation of sound in narrow street canyons

    Science.gov (United States)

    Iu, K. K.; Li, K. M.

    2002-08-01

    This paper addresses an important problem of predicting sound propagation in narrow street canyons with width less than 10 m, which are commonly found in a built-up urban district. Major noise sources are, for example, air conditioners installed on building facades and powered mechanical equipment for repair and construction work. Interference effects due to multiple reflections from building facades and ground surfaces are important contributions in these complex environments. Although the studies of sound transmission in urban areas can be traced back to as early as the 1960s, the resulting mathematical and numerical models are still unable to predict sound fields accurately in city streets. This is understandable because sound propagation in city streets involves many intriguing phenomena such as reflections and scattering at the building facades, diffusion effects due to recessions and protrusions of building surfaces, geometric spreading, and atmospheric absorption. This paper describes the development of a numerical model for the prediction of sound fields in city streets. To simplify the problem, a typical city street is represented by two parallel reflecting walls and a flat impedance ground. The numerical model is based on a simple ray theory that takes account of multiple reflections from the building facades. The sound fields due to the point source and its images are summed coherently such that mutual interference effects between contributing rays can be included in the analysis. Indoor experiments are conducted in an anechoic chamber. Experimental data are compared with theoretical predictions to establish the validity and usefulness of this simple model. Outdoor experimental measurements have also been conducted to further validate the model. copyright 2002 Acoustical Society of America.

  19. A search for narrow states in radiative upsilon decays

    International Nuclear Information System (INIS)

    Lowe, S.T.

    1986-12-01

    A search for new states produced in radiative Υ(1S) decays is accomplished by observing the inclusive photon energy spectrum. A narrow resonance in the energy spectrum indicates the existence of a new state X produced by the process Υ → γX. The analysis is based on approximately 0.44 x 10 6 Υ(1S) events produced at the DORIS II e + e - storage ring. These data were collected with the Crystal Ball detector between April 1983 and May 1986. This analysis finds no evidence for a new state, so upper limits on the branching ratio BR(Υ → γX) are derived, assuming the state X decays primarily to high-multiplicity hadronic final states. In particular, if the state X were a minimal Higgs particle, its primary decay mode would be to the heaviest fermion-antifermion pair energetically available. For the radiative Υ(1S) decays studied here, the heavy fermions would be c anti c or s anti s quark states, over most of the relevant Higgs' mass range. The resulting upper limit for BR(Υ(1S) → γX) is highly energy dependent but for X mass between 1.5 GeV and 8.0 GeV, the 90% confidence level upper limit is better than 8.0 x 10 -4 . For a Higgs' mass near 5.0 GeV, the upper limit is about 2.0 x 10 -4 which is approximately equal to the lowest order calculation for the Wilczek mechanism. The Wilczek calculation with QCD radiative corrections predict branching ratios below the limits set here for all Higgs' masses

  20. World food resources and population: the narrowing margin.

    Science.gov (United States)

    Brown, L R

    1981-09-01

    This bulletin examines the narrowing margin between global food production and population growth. Between 1950 and 1971, world grain production nearly doubled and per capita production increased 31%. During the 1970s, gains in output barely kept pace with population growth, consumption/person declined in sub-Saharan Africa and parts of Asia, food prices were volatile, and over 100 food deficit countries came to depend on the exportable surplus of North America, now the only major grain exporting region. The world fish catch levelled off in the early 1970s and beef production, still dependent mainly on grassland grazing, levelled off in the mid-1970s. With little new land left to plow, satisfying increased food demand now depends on sharp increases in yields on existing crop land. Worldwide, this effort is hampered by loss of topsoil and irrigated land, conversion of cropland to nonfarm uses, rising energy costs, inefficient agrarian structures, particularly in the Soviet Union, the falling yield response to chemical fertilizers in agriculturally advanced countries, and the emerging competition between food and agriculturally based energy crops. Green Revolution successes in some developing countries deomonstrate that, given the right inputs, 3rd world farmers can increase crop yields dramatically. Feeding the world's poor also requires more equitable income and food distribution, including a reduction in the proportion of grain and fish consumed indirectly as livestock products by the affluent. Most important in meeting food needs on a finite planet is braking population growth. The author concludes that every effort should be made to stabilize world production at abour 6 billion by 2020, rather than 10.5 billion by 2110, as is now projected by the UN.

  1. Recovering physical properties from narrow-band photometry

    Science.gov (United States)

    Schoenell, W.; Cid Fernandes, R.; Benítez, N.; Vale Asari, N.

    2013-05-01

    Our aim in this work is to answer, using simulated narrow-band photometry data, the following general question: What can we learn about galaxies from these new generation cosmological surveys? For instance, can we estimate stellar age and metallicity distributions? Can we separate star-forming galaxies from AGN? Can we measure emission lines, nebular abundances and extinction? With what precision? To accomplish this, we selected a sample of about 300k galaxies with good S/N from the SDSS and divided them in two groups: 200k objects and a template library of 100k. We corrected the spectra to z = 0 and converted them to filter fluxes. Using a statistical approach, we calculated a Probability Distribution Function (PDF) for each property of each object and the library. Since we have the properties of all the data from the STARLIGHT-SDSS database, we could compare them with the results obtained from summaries of the PDF (mean, median, etc). Our results shows that we retrieve the weighted average of the log of the galaxy age with a good error margin (σ ≈ 0.1 - 0.2 dex), and similarly for the physical properties such as mass-to-light ratio, mean stellar metallicity, etc. Furthermore, our main result is that we can derive emission line intensities and ratios with similar precision. This makes this method unique in comparison to the other methods on the market to analyze photometry data and shows that, from the point of view of galaxy studies, future photometric surveys will be much more useful than anticipated.

  2. Alcohol advertising and public health: systems perspectives versus narrow perspectives.

    Science.gov (United States)

    Petticrew, M; Shemilt, I; Lorenc, T; Marteau, T M; Melendez-Torres, G J; O'Mara-Eves, A; Stautz, K; Thomas, J

    2017-03-01

    Alcohol consumption is influenced by a complex causal system of interconnected psychological, behavioural, social, economic, legal and environmental factors. These factors are shaped by governments (eg, licensing laws and taxation), by consumers (eg, patterns of alcohol consumption drive demand) and by alcohol industry practices, such as advertising. The marketing and advertising of alcoholic products contributes to an 'alcogenic environment' and is a modifiable influence on alcohol consumption and harm. The public health perspective is that there is sufficient evidence that alcohol advertising influences consumption. The alcohol industry disputes this, asserting that advertising only aims to help consumers choose between brands. We review the evidence from recent systematic reviews, including their theoretical and methodological assumptions, to help understand what conclusions can be drawn about the relationships between alcohol advertising, advertising restrictions and alcohol consumption. A wide evidence base needs to be drawn on to provide a system-level overview of the relationship between alcohol advertising, advertising restrictions and consumption. Advertising aims to influence not just consumption, but also to influence awareness, attitudes and social norms; this is because advertising is a system-level intervention with multiple objectives. Given this, assessments of the effects of advertising restrictions which focus only on sales or consumption are insufficient and may be misleading. For this reason, previous systematic reviews, such as the 2014 Cochrane review on advertising restrictions (Siegfried et al ) contribute important, but incomplete representations of 'the evidence' needed to inform the public health case for policy decisions on alcohol advertising. We conclude that an unintended consequence of narrow, linear framings of complex system-level issues is that they can produce misleading answers. Systems problems require systems perspectives

  3. A search for narrow states in radiative upsilon decays

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, S.T.

    1986-12-01

    A search for new states produced in radiative UPSILON(1S) decays is accomplished by observing the inclusive photon energy spectrum. A narrow resonance in the energy spectrum indicates the existence of a new state X produced by the process UPSILON ..-->.. ..gamma..X. The analysis is based on approximately 0.44 x 10/sup 6/ UPSILON(1S) events produced at the DORIS II e/sup +/e/sup -/ storage ring. These data were collected with the Crystal Ball detector between April 1983 and May 1986. This analysis finds no evidence for a new state, so upper limits on the branching ratio BR(UPSILON ..-->.. ..gamma..X) are derived, assuming the state X decays primarily to high-multiplicity hadronic final states. In particular, if the state X were a minimal Higgs particle, its primary decay mode would be to the heaviest fermion-antifermion pair energetically available. For the radiative UPSILON(1S) decays studied here, the heavy fermions would be c anti c or s anti s quark states, over most of the relevant Higgs' mass range. The resulting upper limit for BR(UPSILON(1S) ..-->.. ..gamma..X) is highly energy dependent but for X mass between 1.5 GeV and 8.0 GeV, the 90% confidence level upper limit is better than 8.0 x 10/sup -4/. For a Higgs' mass near 5.0 GeV, the upper limit is about 2.0 x 10/sup -4/ which is approximately equal to the lowest order calculation for the Wilczek mechanism. The Wilczek calculation with QCD radiative corrections predict branching ratios below the limits set here for all Higgs' masses.

  4. Solar Heating Equipment

    Science.gov (United States)

    1981-01-01

    Solar Unlimited, Inc.'s suncatcher line includes a variety of solar arrays, derived from NASA's satellite program: water heating only, partial home heating, or water and whole house central heating. Solar Unlimited developed a set of vigorous requirements to avoid problems common to solar heating technologies.

  5. Plastic η-factor for Fracture Toughness Test of SA508 Narrow-gap Welds

    International Nuclear Information System (INIS)

    Huh, Yong; Cho, Sung Keun; Koo, Jae Mean; Seok, Chang Sung

    2007-01-01

    In this study, the plastic η-factors of SA508 narrow-gap welding part used for the primary piping system of nuclear power plant were obtained using the finite element analysis and suggested the revised fracture toughness testing method for the narrow-gap welding part. Also, we have performed the fracture toughness test for SA508 narrow-gap welding part applying the new testing method then compared the results with those by fracture toughness test according to ASTM

  6. Luminescent solar concentrators utilizing stimulated emission.

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W; Schmidt, Timothy W; Argyros, Alexander

    2016-03-21

    Luminescent solar concentrators (LSCs) are an emerging technology that aims primarily to reduce the cost of solar energy, with great potential for building integrated photovoltaic (PV) structures. However, realizing LSCs with commercially viable efficiency is currently hindered by reabsorption losses. Here, we introduce an approach to reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire area of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption to allow net gain in the system, and directed towards a small PV cell. A mathematical model, taking into account thermodynamic considerations, of such a system is presented which identifies key parameters and allows evaluation in terms of net effective output power.

  7. Temperature minima in the average thermal structure of the middle mesosphere (70 - 80 km) from analysis of 40- to 92-km SME global temperature profiles

    Science.gov (United States)

    Clancy, R. Todd; Rusch, David W.; Callan, Michael T.

    1994-01-01

    Global temperatures have been derived for the upper stratosphere and mesosphere from analysis of Solar Mesosphere Explorer (SME) limb radiance profiles. The SME temperature represent fixed local time observations at 1400 - 1500 LT, with partial zonal coverage of 3 - 5 longitudes per day over the 1982-1986 period. These new SME temperatures are compared to the COSPAR International Ionosphere Reference Atmosphere 86 (CIRA 86) climatology (Fleming et al., 1990) as well as stratospheric and mesospheric sounder (SAMS); Barnett and Corney, 1984), National Meteorological Center (NMC); (Gelman et al., 1986), and individual lidar and rocket observations. Significant areas of disagreement between the SME and CIRA 86 mesospheric temperatures are 10 K warmer SME temperatures at altitudes above 80 km. The 1981-1982 SAMS temperatures are in much closer agreement with the SME temperatures between 40 and 75 km. Although much of the SME-CIRA 86 disagreement probably stems from the poor vertical resolution of the observations comprising the CIRA 86 modelm, some portion of the differences may reflect 5- to 10-year temporal variations in mesospheric temperatures. The CIRA 86 climatology is based on 1973-1978 measurements. Relatively large (1 K/yr) 5- to 10-year trends in temperatures as functions of longitude, latitude, and altitude have been observed for both the upper stratosphere (Clancy and Rusch, 1989a) and mesosphere (Clancy and Rusch, 1989b; Hauchecorne et al., 1991). The SME temperatures also exhibit enhanced amplitudes for the semiannual oscillation (SAO) of upper mesospheric temperatures at low latitudes, which are not evident in the CIRA 86 climatology. The so-called mesospheric `temperature inversions' at wintertime midlatitudes, which have been observed by ground-based lidar (Hauschecorne et al., 1987) and rocket in situ measurements (Schmidlin, 1976), are shown to be a climatological aspect of the mesosphere, based on the SME observations.

  8. Nonlinear narrow Doppler-free resonances for optical transitions and annihilation radiation of a positronium atom

    International Nuclear Information System (INIS)

    Letokhov, V.S.; Minogin, V.G.

    1976-01-01

    The possibilities of obtaining narrow resonances without the Doppler broadening for transition between the fine structure levels of the ground and first excited states of a positronium atom are considered. An analysis is carried out of the conditions required for observation of the narrow resonances of saturation of single quantum absorption in the 1S-2P transitions and observation of narrow two-photon absorption resonances in the 1S-2S transitions. It is shown that narrow 2γ annihilation radiation lines of a positronium atom may be obtained with a width much smaller than the Doppler one

  9. Solar workshops financial incentives

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    Ten one-day workshops were held across the United States. Information in this workbook is compiled in conjunction with those workshops. The following discussions are included: solar as a fuel (history); why alternative fuels are being sought today; the need for conservation; advantages of solar energy; the potential of solar energy; why solar energy is not more widely used; a definition of solar; how solar can help meet energy demands; Federal policies and programs; what solar technologies exist today that can be effectively utilized (thermal applications, fuels from biomass, solar electric). Additional information is presented in three attachments: Energy-Conserving Methods; Domestic Policy Review of Solar Energy; and DOE Secretary's Annual Report to Congress-Solar Section. (MCW)

  10. Photovoltaic solar concentrator

    Science.gov (United States)

    Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J.; Sanchez, Carlos Anthony; Clews, Peggy J.; Gupta, Vipin P.

    2015-09-08

    A process including forming a photovoltaic solar cell on a substrate, the photovoltaic solar cell comprising an anchor positioned between the photovoltaic solar cell and the substrate to suspend the photovoltaic solar cell from the substrate. A surface of the photovoltaic solar cell opposite the substrate is attached to a receiving substrate. The receiving substrate may be bonded to the photovoltaic solar cell using an adhesive force or a metal connecting member. The photovoltaic solar cell is then detached from the substrate by lifting the receiving substrate having the photovoltaic solar cell attached thereto and severing the anchor connecting the photovoltaic solar cell to the substrate. Depending upon the type of receiving substrate used, the photovoltaic solar cell may be removed from the receiving substrate or remain on the receiving substrate for use in the final product.

  11. Synchronized Northern Hemisphere climate change and solar magnetic cycles during the Maunder Minimum.

    Science.gov (United States)

    Yamaguchi, Yasuhiko T; Yokoyama, Yusuke; Miyahara, Hiroko; Sho, Kenjiro; Nakatsuka, Takeshi

    2010-11-30

    The Maunder Minimum (A.D. 1645-1715) is a useful period to investigate possible sun-climate linkages as sunspots became exceedingly rare and the characteristics of solar cycles were different from those of today. Here, we report annual variations in the oxygen isotopic composition (δ(18)O) of tree-ring cellulose in central Japan during the Maunder Minimum. We were able to explore possible sun-climate connections through high-temporal resolution solar activity (radiocarbon contents; Δ(14)C) and climate (δ(18)O) isotope records derived from annual tree rings. The tree-ring δ(18)O record in Japan shows distinct negative δ(18)O spikes (wetter rainy seasons) coinciding with rapid cooling in Greenland and with decreases in Northern Hemisphere mean temperature at around minima of decadal solar cycles. We have determined that the climate signals in all three records strongly correlate with changes in the polarity of solar dipole magnetic field, suggesting a causal link to galactic cosmic rays (GCRs). These findings are further supported by a comparison between the interannual patterns of tree-ring δ(18)O record and the GCR flux reconstructed by an ice-core (10)Be record. Therefore, the variation of GCR flux associated with the multidecadal cycles of solar magnetic field seem to be causally related to the significant and widespread climate changes at least during the Maunder Minimum.

  12. Instrumentation for remote sensing solar radiation from light aircraft.

    Science.gov (United States)

    Howard, J A; Barton, I J

    1973-10-01

    The paper outlines the instrumentation needed to study, from a light aircraft, the solar radiation reflected by ground surfaces and the incoming solar radiation. A global shortwave radiometer was mounted on the roof of the aircraft and a specially designed mount was used to support a downward pointing 70-mm aerial camera, a downward pointing narrow-beam pyranometer, and, sometimes, a downward pointing global shortwave pyranometer. Calibration factors were determined for the three pyranometers by comparison with a standard Angstrom compensation pyrheliometer. Results have indicated trends in the albedos of major plant communities and have shown that the calculated albedo values vary according to whether the downward pointing instrument is narrow-beam or global. Comparisons were also made with albedos measured on the ground.

  13. Hybrid Solar Cooking

    OpenAIRE

    Prasanna, UR; Umanand, L

    2010-01-01

    In the existing traditional solar cookers, the cooking is performed near the collector which may be at an inconvenient location for cooking purposes. This paper proposes a hybrid solar cooking system where the solar energy is brought to the kitchen. The energy source is a combination of the solar thermal energy and the Liquefied Petroleum Gas (LPG) that is very common in kitchens. The solar thermal energy is transferred to the kitchen by means of a circulating fluid like oil. The transfer of ...

  14. Solar collector array

    Science.gov (United States)

    Hall, John Champlin; Martins, Guy Lawrence

    2015-09-06

    A method and apparatus for efficient manufacture, assembly and production of solar energy. In one aspect, the apparatus may include a number of modular solar receiver assemblies that may be separately manufactured, assembled and individually inserted into a solar collector array housing shaped to receive a plurality of solar receivers. The housing may include optical elements for focusing light onto the individual receivers, and a circuit for electrically connecting the solar receivers.

  15. Development of Solar Research

    Science.gov (United States)

    Wittmann, Axel D.; Wolfschmidt, Gudrun; Duerbeck, Hilmar W.

    Originally based on a workshop on “Development of Solar Research”, held in Freiburg/Breisgau, this book contains articles on megalithic structures, the Nebra sky-disk, ancient sun cults, the observation of sunspots, the photography of the sun during eclipses, eclipse maps and expeditions, solar telescopes, solar physics during the Nazi era, archives of solar observations, scientific ballooning for solar research, site-testing on the Canary Islands, as well as on international cooperation.

  16. Minimal thermodynamic conditions in the reservoir to produce steam at the Cerro Prieto geothermal field, BC; Condiciones termodinamicas minimas del yacimiento para producir vapor en el campo geotermico de Cerro Prieto, B.C.

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Rodriguez; Marco Helio [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: marco.rodriguez01@cfe.gob.mx

    2009-01-15

    Minimal thermodynamic conditions in the Cerro Prieto geothermal reservoir for steam production are defined, taking into account the minimal acceptable steam production at the surface, considering a rank of mixed-enthalpies for different well-depths, and allowing proper assessments for the impacts of the changes in fluid reservoir pressure and enthalpy. Factors able to influence steam production are discussed. They have to be considered when deciding whether or not to drill or repair a well in a particular area of the reservoir. These evaluations become much more relevant by considering the huge thermodynamic changes that have occurred at the Cerro Prieto geothermal reservoir from its development, starting in 1973, which has lead to abandoning some steam producing areas in the field. [Spanish] Las condiciones termodinamicas minimas del yacimiento geotermico de Cerro Prieto, BC, para producir vapor se determinan tomando en cuenta la minima produccion de vapor aceptable en superficie, considerando un rango de entalpias de la mezcla y para diferentes profundidades de pozos, lo que permite valorar adecuadamente el impacto de la evolucion de la presion y entalpia del fluido en el yacimiento. Se discuten los factores que pueden afectar la produccion de vapor, los cuales se deben tomar en cuenta para determinar la conveniencia o no de perforar o reparar un pozo en determinada zona del yacimiento. Estas evaluaciones adquieren gran relevancia al considerar los enormes cambios termodinamicos que ha presentado el yacimiento geotermico de Cerro Prieto, como resultado de su explotacion iniciada en 1973, lo que ha llevado a abandonar algunas zonas del campo para la produccion de vapor. Palabras Clave: Cerro Prieto, entalpia, evaluacion de yacimientos, politicas de explotacion, presion, produccion de vapor.

  17. Solar Club

    CERN Multimedia

    Solar Club

    2012-01-01

      Le  CERN Solar Club tiendra son Assemblée Générale le Mercredi  4 avril, à 18h00 dans la salle C, bat.61, 1e étage de 18h00  à  19h30. Grande table ronde avec  présentations de projets concernant toute forme d’Energie  Renouvelable par des membres du club,  et… par  VOUS, nos invités. Au programme : - L’E-push : petite remorque électrique, qui pousse vôtre vélo par Robert Becker. - Le Stockage Saisonnier Sous-Lacustre d’Energie Solaire (S3LES) par  William van Sprolant. - Compte-Rendu de plusieurs conférences récentes concernant les E.R. par Jacques Dupin. - VOS  Projets ou Sujets (contactez : paul.gelissen@orange.fr). - Partie «administrative» avec rapport d’activités, rapport fina...

  18. Eilat virus displays a narrow mosquito vector range.

    Science.gov (United States)

    Nasar, Farooq; Haddow, Andrew D; Tesh, Robert B; Weaver, Scott C

    2014-12-17

    mosquito host. As a consequence, EILV displays a narrow vector range in mosquito species responsible for the maintenance of other alphaviruses in nature.

  19. Optogenetic Central Amygdala Stimulation Intensifies and Narrows Motivation for Cocaine.

    Science.gov (United States)

    Warlow, Shelley M; Robinson, Mike J F; Berridge, Kent C

    2017-08-30

    Addiction is often characterized by intense motivation for a drug, which may be narrowly focused at the expense of other rewards. Here, we examined the role of amygdala-related circuitry in the amplification and narrowing of motivation focus for intravenous cocaine. We paired optogenetic channelrhodopsin (ChR2) stimulation in either central nucleus of amygdala (CeA) or basolateral amygdala (BLA) of female rats with one particular nose-poke porthole option for earning cocaine infusions (0.3 mg/kg, i.v.). A second alternative porthole earned identical cocaine but without ChR2 stimulation. Consequently, CeA rats quickly came to pursue their CeA ChR2-paired cocaine option intensely and exclusively, elevating cocaine intake while ignoring their alternative cocaine alone option. By comparison, BLA ChR2 pairing failed to enhance cocaine motivation. CeA rats also emitted consummatory bites toward their laser-paired porthole, suggesting that higher incentive salience made that cue more attractive. A separate progressive ratio test of incentive motivation confirmed that CeA ChR2 amplified rats' motivation, raising their breakpoint effort price for cocaine by 10-fold. However, CeA ChR2 laser on its own lacked any reinforcement value: laser by itself was never self-stimulated, not even by the same rats in which it amplified motivation for cocaine. Conversely, CeA inhibition by muscimol/baclofen microinjections prevented acquisition of cocaine self-administration and laser preference, whereas CeA inhibition by optogenetic halorhodopsin suppressed cocaine intake, indicating that CeA circuitry is needed for ordinary cocaine motivation. We conclude that CeA ChR2 excitation paired with a cocaine option specifically focuses and amplifies motivation to produce intense pursuit and consumption focused on that single target. SIGNIFICANCE STATEMENT In addiction, intense incentive motivation often becomes narrowly focused on a particular drug of abuse. Here we show that pairing central

  20. Observations and computations of narrow Kelvin ship wakes

    Directory of Open Access Journals (Sweden)

    Francis Noblesse

    2016-01-01

    Full Text Available Computations of far-field ship waves, based on linear potential flow theory and the Hogner approximation, are reported for monohull ships and catamarans. Specifically, far-field ship waves are computed for six monohull ships at four Froude numbers F≡V/gL=0.58, 0.68, 0.86, 1.58 and for six catamarans with nondimensional hull spacing s≡S/L=0.25 at two Froude numbers Fs≡V/gS=1 and 2.5. Here, g is the gravitational acceleration, V and L denote the ship speed and length, and S is the separation distance between the twin hulls of a catamaran. The computations show that, although the amplitudes of the waves created by a ship are strongly influenced by the shape of the ship hull, as well known, the ray angles where the largest waves are found are only weakly influenced by the hull shape and indeed are mostly a kinematic feature of the flow around a ship hull. An important practical consequence of this flow feature is that the apparent wake angle of general monohull ships or catamarans (with arbitrarily-shaped hulls can be estimated, without computations, by means of simple analytical relations; these relations, obtained elsewhere via parametric computations, are given here. Moreover, the influence of the two parameters Fs and s that largely determine the ray angles of the dominant waves created by a catamaran is illustrated via computations for three catamarans with hull spacings s=0.2, 0.35, 0.5 at four Froude numbers Fs=1, 1.5, 2, 2.5. These computations confirm that the largest waves created by wide and/or fast catamarans are found at ray angles that only depend on Fs (i.e. that do not depend on the hull spacing s in agreement with an elementary analysis of lateral interference between the dominant waves created by the bows (or sterns of the twin hulls of a catamaran. The dominant-waves ray angles predicted by the theory of wave-interference effects for monohull ships and catamarans are also compared with the observations of narrow Kelvin ship

  1. High-efficiency concentrator silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. (Stanford Univ., CA (USA). Solid-State Electronics Lab.)

    1990-11-01

    This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm{sup 2} cell with front grids achieved 26% efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

  2. Solar Design Workbook

    Energy Technology Data Exchange (ETDEWEB)

    Franta, G.; Baylin, F.; Crowther, R.; Dubin, F.; Grace, A., Griffith, J.W.; Holtz, M.; Kutscher, C.; Nordham, D.; Selkowitz, S.; Villecco, M.

    1981-06-01

    This Solar Design Workbook presents solar building design applications for commercial buildir^s. The book is divided into four sections. The first section describes the variety of solar applications in buildings including conservation aspects, solar fundamentals, passive systems, active systems, daylighting, and other solar options. Solar system design evaluation techniques including considerations for building energy requirements, passive systems, active systems, and economics are presented in Section II. The third section attempts to assist the designer in the building design process for energy conservation and solar applications including options and considerations for pre-design, design, and post-design phases. The information required for the solar design proee^ has not been fully developed at this time. Therefore, Section III is incomplete, but an overview of the considerations with some of the design proces elements is presented. Section IV illustrates ease studies that utilize solar applications in the building design.

  3. Fracture strength and probability of survival of narrow and extra-narrow dental implants after fatigue testing: In vitro and in silico analysis.

    Science.gov (United States)

    Bordin, Dimorvan; Bergamo, Edmara T P; Fardin, Vinicius P; Coelho, Paulo G; Bonfante, Estevam A

    2017-07-01

    To assess the probability of survival (reliability) and failure modes of narrow implants with different diameters. For fatigue testing, 42 implants with the same macrogeometry and internal conical connection were divided, according to diameter, as follows: narrow (Ø3.3×10mm) and extra-narrow (Ø2.9×10mm) (21 per group). Identical abutments were torqued to the implants and standardized maxillary incisor crowns were cemented and subjected to step-stress accelerated life testing (SSALT) in water. The use-level probability Weibull curves, and reliability for a mission of 50,000 and 100,000 cycles at 50N, 100, 150 and 180N were calculated. For the finite element analysis (FEA), two virtual models, simulating the samples tested in fatigue, were constructed. Loading at 50N and 100N were applied 30° off-axis at the crown. The von-Mises stress was calculated for implant and abutment. The beta (β) values were: 0.67 for narrow and 1.32 for extra-narrow implants, indicating that failure rates did not increase with fatigue in the former, but more likely were associated with damage accumulation and wear-out failures in the latter. Both groups showed high reliability (up to 97.5%) at 50 and 100N. A decreased reliability was observed for both groups at 150 and 180N (ranging from 0 to 82.3%), but no significant difference was observed between groups. Failure predominantly involved abutment fracture for both groups. FEA at 50N-load, Ø3.3mm showed higher von-Mises stress for abutment (7.75%) and implant (2%) when compared to the Ø2.9mm. There was no significant difference between narrow and extra-narrow implants regarding probability of survival. The failure mode was similar for both groups, restricted to abutment fracture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Solar Adaptive Optics

    Directory of Open Access Journals (Sweden)

    Thomas R. Rimmele

    2011-06-01

    Full Text Available Adaptive optics (AO has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO and Ground-Layer AO (GLAO will be given.

  5. Principles of solar engineering

    CERN Document Server

    Goswami, D Yogi

    2015-01-01

    Introduction to Solar Energy ConversionGlobal Energy Needs and ResourcesSolar EnergyEnergy StorageEconomics of Solar SystemsSummary of RE ResourcesForecast of Future Energy MixReferencesFundamentals of Solar RadiationThe Physics of the Sun and Its Energy TransportThermal Radiation FundamentalsSun-Earth Geometric RelationshipSolar RadiationEstimation of Terrestrial Solar RadiationModels Based on Long-Term Measured Horizontal Solar RadiationMeasurement of Solar RadiationSolar Radiation Mapping Using Satellite DataReferencesSuggested ReadingsSolar Thermal CollectorsRadiative Properties and Characteristics of MaterialsFlat-Plate CollectorsTubular Solar Energy CollectorsExperimental Testing of CollectorsConcentrating Solar CollectorsParabolic Trough ConcentratorCompound-Curvature Solar ConcentratorsCentral Receiver CollectorFresnel Reflectors and LensesSolar Concentrator SummaryReferencesSuggested ReadingThermal Energy Storage and TransportThermal Energy StorageTypes of TESDesign of Storage SystemEnergy Transport ...

  6. 78 FR 67086 - Safety Zone, Submarine Cable Replacement Operations, Kent Island Narrows; Queen Anne's County, MD

    Science.gov (United States)

    2013-11-08

    ... 1625-AA00 Safety Zone, Submarine Cable Replacement Operations, Kent Island Narrows; Queen Anne's County... vessels on navigable waters during submarine cable replacement operations at the Kent Island Narrows (MD... involves the installation of a submarine cable within a federal navigation channel requiring divers, a...

  7. 77 FR 32938 - Narrow Woven Ribbons With Woven Selvedge From Taiwan: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2012-06-04

    ..., 2010), as amended in Narrow Woven Ribbons With Woven Selvedge From Taiwan and the People's Republic of... of the fabric); (10) Narrow woven ribbon affixed (including by tying) as a decorative detail to non... woven ribbon that is (a) affixed to non-subject merchandise as a working component of such non-subject...

  8. Brief Daily Exposures to Asian Females Reverses Perceptual Narrowing for Asian Faces in Caucasian Infants

    Science.gov (United States)

    Anzures, Gizelle; Wheeler, Andrea; Quinn, Paul C.; Pascalis, Olivier; Slater, Alan M.; Heron-Delaney, Michelle; Tanaka, James W.; Lee, Kang

    2012-01-01

    Perceptual narrowing in the visual, auditory, and multisensory domains has its developmental origins during infancy. The current study shows that experimentally induced experience can reverse the effects of perceptual narrowing on infants' visual recognition memory of other-race faces. Caucasian 8- to 10-month-olds who could not discriminate…

  9. Narrowing the Gap in Outcomes: Early Years (0-5 Years)

    Science.gov (United States)

    Springate, Ian; Atkinson, Mary; Straw, Suzanne; Lamont, Emily; Grayson, Hilary

    2008-01-01

    This report was commissioned by the Local Government Association (LGA) to inform the Department for Children, Schools and Families (DCSF) and LGA work on "Narrowing the Gap." It focuses on early years' provision and presents findings from a review of the best evidence on narrowing the gap in outcomes across the five Every Child Matters…

  10. Narrow line width operation of a 980 nm gain guided tapered diode laser bar

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Barrientos-Barria, Jessica

    2011-01-01

    We demonstrate two different schemes for the spectral narrowing of a 12 emitter 980 nm gain guided tapered diode laser bar. In the first scheme, a reflective grating has been used in a Littman Metcalf configuration and the wavelength of the laser emission could be narrowed down from more than 5.5...

  11. 75 FR 53711 - Narrow Woven Ribbons With Woven Selvedge From China and Taiwan

    Science.gov (United States)

    2010-09-01

    ... Woven Ribbons With Woven Selvedge From China and Taiwan Determinations On the basis of the record \\1... by reason of imports of narrow woven ribbons with woven selvedge from China, primarily provided for... reason of imports of narrow woven ribbons with woven selvedge from Taiwan, primarily provided for in...

  12. Forecast of the Next Solar Activity Cycle and Thereafter

    Science.gov (United States)

    Duhau, S.; de Jager, C.

    2008-05-01

    Solar variability is controlled by the internal dynamo which is a nonlinear system. It is therefore unpredictable in principle (Tobias, 2004). Yet we have found that the system shows regularities, in line with what can be expected from chaos theory (Duhau ad de Jager, 2008). It is dominated by an attractor state to which the system returns more or less regularly. In addition we distinguish between Grand Maxima, Grand Minima and periods of a more regular oscillation around the attractor state level. Here, we show that the dynamo system is presently undergoing a transition from the recent Grand Maximum to another regime. This transition started in 2000 and is expected to end around the maximum of cycle #24, that we foresee for 2012 - 2013. At that time the maximum sunspot number Rmax will be 70 ± 17, where the 'error' is the largest conceivable deviation from the expected value. At that time a period of lower solar activity will start. That period will most probably be a regular quasiperiodic episode, as occurred between 1730 and 1925. It is characterized by the superposition of weak 'regular' Gleissberg cycle and decadal oscillations. These last will be negative and might turn out to be very strong, as around 1810, in which case a Dalton-type Grand Minimum would develop. This moderate to low-activity episode is expected to last for an integer number of Gleissberg cycles.

  13. The 11-year solar cycle, the 27-day Sun's rotation and the area of the stratospheric Aleutian high

    Directory of Open Access Journals (Sweden)

    Boris Soukharev

    2001-03-01

    Full Text Available The effect of the 11-year solar cycle on the 30-hPa geopotential height and temperature fields in the area of the Aleutian high caused by solar activity oscillations resulting from the Sun's rotation (27.2 d is investigated, applying methods of statistical cross-spectral analysis to daily data for the period from 1965 to 1998. The area of the stratospheric Aleutian high is considered as an 'indicator' of the solar influence on the winter stratosphere proceeding from the results by LABITZKE and VAN LOON (1988, and VAN LOON and LABITZKE (1990. An effect of the 11-year solar cycle on the response of the summer middle stratosphere to solar activity oscillations on the time scale of the Sun's rotation is not found. In contrast to summer, the atmospheric responses in winter demonstrate clear differences between maximum and minimum of the 11-year solar cycle for the 27.2 d solar rotation periodicity and for the two other oscillations of 29.4 d and 25.3 d, resulting from the modulation of the 27.2 d solar-induced periodicity by the annual atmospheric variation. The atmospheric response for the fourth periodicity studied, the 17 d oscillation, which is supposed to be a normal mode of the atmosphere, close to the known 16-day wave (MADDEN, 1978, also shows a clear dependence on the 11-year solar cycle. For all the periodicities studied the coherence between the 10.7 cm solar radio flux and the 30-hPa height/temperature fields in the Aleutian high area in winter is on the average stronger at maxima than at minima of the 11-year solar cycle. The corresponding amplitudes of the solar-induced geopotential height and temperature perturbations are also larger at high than at low solar activity, with the largest differences revealed at the moderate and polar latitudes. Thus, we conclude that the response of the winter 30-hPa height/temperature fields in the area of the Aleutian high to solar oscillations on the time scale of the Sun's rotation is on the average

  14. Enhanced Electron Photoemission by Collective Lattice Resonances in Plasmonic Nanoparticle-Array Photodetectors and Solar Cells

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Babicheva, Viktoriia; Uskov, Alexander

    2014-01-01

    We propose to use collective lattice resonances in plasmonic nanoparticle arrays to enhance and tailor photoelectron emission in Schottky barrier photodetectors and solar cells. We show that the interaction between narrow-band lattice resonances (the Rayleigh anomaly) and broader-band individual-...

  15. ACRIM-gap and total solar irradiance revisited: Is there a secular trend between 1986 and 1996?

    Science.gov (United States)

    Krivova, N. A.; Solanki, S. K.; Wenzler, T.

    2009-10-01

    A gap in the total solar irradiance (TSI) measurements between ACRIM-1 and ACRIM-2 led to the ongoing debate on the presence or not of a secular trend between the minima preceding cycles 22 (in 1986) and 23 (1996). It was recently proposed to use the SATIRE model of solar irradiance variations to bridge this gap. When doing this, it is important to use the appropriate SATIRE-based reconstruction, which we do here, employing a reconstruction based on magnetograms. The accuracy of this model on months to years timescales is significantly higher than that of a model developed for long-term reconstructions used by the ACRIM team for such an analysis. The constructed ‘mixed’ ACRIM — SATIRE composite shows no increase in the TSI from 1986 to 1996, in contrast to the ACRIM TSI composite.

  16. Solar renovation demonstration projects

    Energy Technology Data Exchange (ETDEWEB)

    Bruun Joergensen, O. [ed.

    1998-10-01

    In the framework of the IEA SHC Programme, a Task on building renovation was initiated, `Task 20, Solar Energy in Building Renovation`. In a part of the task, Subtask C `Design of Solar Renovation Projects`, different solar renovation demonstration projects were developed. The objective of Subtask C was to demonstrate the application of advanced solar renovation concepts on real buildings. This report documents 16 different solar renovation demonstration projects including the design processes of the projects. The projects include the renovation of houses, schools, laboratories, and factories. Several solar techniques were used: building integrated solar collectors, glazed balconies, ventilated solar walls, transparent insulation, second skin facades, daylight elements and photovoltaic systems. These techniques are used in several simple as well as more complex system designs. (au)

  17. Solar Thermal Energy Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Pitsenbarger, J. [eds.

    1996-02-01

    Solar Thermal Energy Technology (PST) announces on a bimonthly basis the current worldwide research and development information that would expand the technology base required for the advancement of solar thermal systems as a significant energy resource.

  18. Solar power roof shingle

    Science.gov (United States)

    Forestieri, A. F.; Ratajczak, A. F.; Sidorak, L. G.

    1975-01-01

    Silicon solar cell module provides both all-weather protection and electrical power. Module consists of array of circular silicon solar cells bonded to fiberglass substrate roof shingle with fluorinated ethylene propylene encapsulant.

  19. Solar Dynamics Observatory

    Data.gov (United States)

    National Aeronautics and Space Administration — A searchable database of all Solar Dynamics Observatory data including EUV, magnetograms, visible light and X-ray. SDO: The Solar Dynamics Observatory is the first...

  20. Aeronet Solar Flux

    Data.gov (United States)

    National Aeronautics and Space Administration — SolRad-Net (Solar Radiation Network) is an established network of ground-based sensors providing high-frequency solar flux measurements in quasi-realtime to the...

  1. Solar Indices - Sunspot Numbers

    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...

  2. Solar engineering 1994

    International Nuclear Information System (INIS)

    Klett, D.E.; Hogan, R.E.; Tanaka, Tadayoshi

    1994-01-01

    This volume of 83 papers constitutes the Proceedings of the 1994 International Solar Energy Conference held March 27--30, 1994 in San Francisco, California. The Conference was jointly sponsored by the Solar Energy Division of the American Society of Mechanical Engineers, The Japan Society of Mechanical Engineers and the Japan Solar Energy Society. This is the fourth cooperation between ASME, JSME and JSES in cosponsoring the International Solar Energy Conference. The papers cover a wide range of solar technologies from low temperature solar ponds and desalinization to high temperature concentrators for space applications and central receivers for terrestrial power generation. Other topics covered include solar detoxification of hazardous waste, dish Stirling systems, solar cooling, photovoltaics, building energy analysis and conservation, simulation, and testing and measurement techniques. All papers were indexed separately for the data base

  3. Solar Resource Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Renne, D.; George, R.; Wilcox, S.; Stoffel, T.; Myers, D.; Heimiller, D.

    2008-02-01

    This report covers the solar resource assessment aspects of the Renewable Systems Interconnection study. The status of solar resource assessment in the United States is described, and summaries of the availability of modeled data sets are provided.

  4. Solar Indices - Plage Regions

    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...

  5. [Can solar/geomagnetic activity restrict the occurrence of some shellfish poisoning outbreaks? The example of PSP caused by Gymnodinium catenatum at the Atlantic Portuguese coast].

    Science.gov (United States)

    Vale, P

    2013-01-01

    Cyclic outbreaks of accumulation of paralytic shellfish poisoning (PSP) toxins in mussels attributed to Gymnodinium catenatum blooms displayed several of the highest inter-annual maxima coincidental with minima of the 11-year solar sunspot number (SSN) cycle. The monthly distribution of PSP was associated with low levels of the solar radio flux, a more quantitative approach than SSN for fluctuations in solar activity. A comparison between monthly distribution of PSP and other common biotoxins (okadaic acid (OA), dinophysistoxin-2 (DTX2) and amnesic shellfish poisoning (ASP) toxins) demonstrated that only PSP was significantly associated with low levels of radio flux (p < 0.01). PSP occurrence suggests a prior decline in solar activity could be required to act as a trigger, in a similar manner to a photoperiodic signal. The seasonal frequency increased towards autumn during the study period, which might be related to the progressive atmospheric cut-off of deleterious radiation associated with the seasonal change in solar declination, and might play an additional role in seasonal signal-triggering. PSP distribution was also associated with low levels of the geomagnetic index Aa. A comparison between monthly distribution of PSP and other common biotoxins, also demonstrated that only PSP was significantly associated with low levels of the Aa index (p < 0.01). In some years of SSN minima no significant PSP-outbreaks in mussels were detected. This was attributed to a steady rise in geomagnetic activity that could disrupt the triggering signal. Global distribution patterns show that hotspots for G. catenatum blooms are regions with deficient crustal magnetic anomalies. In addition to the variable magnetic field mostly of solar origin, static fields related to magnetized rocks in the crust and upper mantle might play a role in restricting worldwide geographic distribution.

  6. Emerging Solar Technologies: Perovskite Solar Cell

    Indian Academy of Sciences (India)

    tus of hybrid perovskite solar cells. 1. Introduction. Gradually, primary energy resources such as fossil fuels, coal, and natural gas are depleting, while the global energy consump- tion is increasing. Solar energy, along with wind, biomass, tidal, and geothermal sources is emerging as an answer to our energy- starved planet.

  7. Durable solar mirror films

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.; Katare, Rajesh K.; Jing, Naiyong; North, Diane; Peterson, Eric M.

    2017-02-14

    The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

  8. Solar Energy Technician/Installer

    Science.gov (United States)

    Moore, Pam

    2007-01-01

    Solar power (also known as solar energy) is solar radiation emitted from the sun. Large panels that absorb the sun's energy as the sun beats down on them gather solar power. The energy in the rays can be used for heat (solar thermal energy) or converted to electricity (photovoltaic energy). Each solar energy project, from conception to…

  9. Experimenting with Solar Energy

    Science.gov (United States)

    Roman, Harry T.

    2004-01-01

    Over the past 25 years, the author has had the opportunity to study the subject of solar energy and to get involved with the installation, operation, and testing of solar energy systems. His work has taken him all over the United States and put him in contact with solar experts from around the world. He has also had the good fortune of seeing some…

  10. Alternatives in solar energy

    Science.gov (United States)

    Schueler, D. G.

    1978-01-01

    Although solar energy has the potential of providing a significant source of clean and renewable energy for a variety of applications, it is expected to penetrate the nation's energy economy very slowly. The alternative solar energy technologies which employ direct collection and conversion of solar radiation as briefly described.

  11. Solar energy potential

    Science.gov (United States)

    1973-01-01

    The potential of solar energy as a national resource is discussed. Research and development programs for the development of eleven concepts are described to show the proposed funding for each year over a fifteen year period. The estimated energy contributions by period for each of the solar concepts are analyzed. The estimated impact of the solar concepts to the year 2020 are tabulated.

  12. Solar tracking system

    Science.gov (United States)

    Okandan, Murat; Nielson, Gregory N.

    2016-07-12

    Solar tracking systems, as well as methods of using such solar tracking systems, are disclosed. More particularly, embodiments of the solar tracking systems include lateral supports horizontally positioned between uprights to support photovoltaic modules. The lateral supports may be raised and lowered along the uprights or translated to cause the photovoltaic modules to track the moving sun.

  13. Solar cell concentrating system

    International Nuclear Information System (INIS)

    Garg, H.P.; Sharma, V.K.; Agarwal, R.K.

    1986-11-01

    This study reviews fabrication techniques and testing facilities for different solar cells under concentration which have been developed and tested. It is also aimed to examine solar energy concentrators which are prospective candidates for photovoltaic concentrator systems. This may provide an impetus to the scientists working in the area of solar cell technology

  14. Nanostructured Organic Solar Cells

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Rubahn, Horst-Günter; Madsen, Morten

    Recent forecasts for alternative energy generation predict emerging importance of supporting state of art photovoltaic solar cells with their organic equivalents. Despite their significantly lower efficiency, number of application niches are suitable for organic solar cells. This work reveals...... the principles of bulk heterojunction organic solar cells fabrication as well as summarises major differences in physics of their operation....

  15. InGaP Heterojunction Barrier Solar Cells

    Science.gov (United States)

    Welser, Roger E. (Inventor)

    2014-01-01

    A new solar cell structure called a heterojunction barrier solar cell is described. As with previously reported quantum-well and quantum-dot solar cell structures, a layer of narrow band-gap material, such as GaAs or indium-rich InGaP, is inserted into the depletion region of a wide band-gap PN junction. Rather than being thin, however, the layer of narrow band-gap material is about 400-430 nm wide and forms a single, ultrawide well in the depletion region. Thin (e.g., 20-50 nm), wide band-gap InGaP barrier layers in the depletion region reduce the diode dark current. Engineering the electric field and barrier profile of the absorber layer, barrier layer, and p-type layer of the PN junction maximizes photogenerated carrier escape. This new twist on nanostructured solar cell design allows the separate optimization of current and voltage to maximize conversion efficiency.

  16. Modulation of galactic cosmic rays in solar cycles 22-24: Analysis and physical interpretation

    Science.gov (United States)

    Kalinin, M. S.; Bazilevskaya, G. A.; Krainev, M. B.; Svirzhevskaya, A. K.; Svirzhevsky, N. S.; Starodubtsev, S. A.

    2017-09-01

    This work represents a physical interpretation of cosmic ray modulation in the 22nd-24th solar cycles, including an interpretation of an unusual behavior of their intensity in the last minimum of the solar activity (2008-2010). In terms of the Parker modulation model, which deals with regularly measured heliospheric characteristics, it is shown that the determining factor of the increased intensity of the galactic cosmic rays in the minimum of the 24th solar cycle is an anomalous reduction of the heliospheric magnetic field strength during this time interval under the additional influence of the solar wind velocity and the tilt angle of the heliospheric current sheet. We have used in the calculations the dependence of the diffusion tensor on the rigidity in the form K ij ∝ R 2-μ with μ = 1.2 in the sector zones of the heliospheric magnetic field and with μ = 0.8 outside the sector zones, which leads to an additional amplification of the diffusion mechanism of cosmic ray modulation. The proposed approach allows us to describe quite satisfactorily the integral intensity of protons with an energy above 0.1 GeV and the energy spectra in the minima of the 22nd-24th solar cycles at the same value of the free parameter. The determining factor of the anomalously high level of the galactic cosmic ray intensity in the minimum of the 24th solar cycle is the significant reduction of the heliospheric magnetic field strength during this time interval. The forecast of the intensity level in the minimum of the 25th solar cycle is provided.

  17. A polycrystalline SiO2 colloidal crystal film with ultra-narrow reflections.

    Science.gov (United States)

    Fu, Qianqian; Chen, Ang; Shi, Lei; Ge, Jianping

    2015-04-30

    This work reported a high quality photonic crystal film with an ultra-narrow photonic bandgap obtained via a chemical synthetic route. The bandgap is much narrower than that of traditional colloidal crystals, which makes the film qualified for use in optical devices. The narrow PBG originates from not only the high crystallinity and uniform orientations of microcrystals within the film but also the very close refractive indices between the silica and the polymer matrix. Due to the matching of the refractive index, the amorphous contents of the film are optically transparent and do not interfere with the reflection, so that the photonic crystal film is tolerant of the existence of disordered contents.

  18. 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

  19. Solar radiation absorbing material

    Science.gov (United States)

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  20. Solar energy conversion systems

    CERN Document Server

    Brownson, Jeffrey R S

    2013-01-01

    Solar energy conversion requires a different mind-set from traditional energy engineering in order to assess distribution, scales of use, systems design, predictive economic models for fluctuating solar resources, and planning to address transient cycles and social adoption. Solar Energy Conversion Systems examines solar energy conversion as an integrative design process, applying systems thinking methods to a solid knowledge base for creators of solar energy systems. This approach permits different levels of access for the emerging broad audience of scientists, engineers, architects, planners

  1. Solar energy in Israel

    International Nuclear Information System (INIS)

    Zvirin, Y.; Zamkow, S.

    1993-01-01

    The state of Israel has been a pioneer in the solar energy development and utilization since it was founded. In the 50's solar domestic home heaters became commercially available. At the same time research work has been started in different areas of solar energy, which led to more advanced solar systems for additional applications. The presentation includes some details of commercial utilization of solar energy and a brief description of the main Research and Development projects in industry, universities and research institutes. (authors)

  2. A tunable, solid, Fabry-Perot etalon for solar seismology

    Science.gov (United States)

    Rust, David M.; Burton, Clive H.; Leistner, Achim J.

    1986-01-01

    A solid etalon has been designed and fabricated from a 50-mm diameter wafer of optical-quality lithium niobate. The finished etalon has a free spectral range of 0.325 nm at 588 nm. The parallel faces are coated with silver, and the central 15-mm aperture of the etalon has a finesse of 18.6. The reflective faces double as electrodes, and application of voltage will shift the passband. This feature was used in a servo circuit to stabilize the passband against temperature and tilt-induced drifts to better than three parts in one billion. Operated in the stabilized mode for day-long sessions, this filter alternately samples the wings of a narrow atomic absorption line in the solar spectrum and produces a signal proportional to velocity on the solar disk. The Fourier transform of this signal yields information on acoustic waves in the solar interior.

  3. Photovoltaic solar concentrator

    Science.gov (United States)

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2016-03-15

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  4. Frequency agile solar radiotelescope

    Science.gov (United States)

    Bastian, Tim S.

    2003-02-01

    The Frequency Agile Solar Radiotelescope (FASR) is a solar-dedicated, ground based, interferometric array optimized to perform broadband imaging spectroscopy from ~ 0.1-30+ GHz. It will do so with the angular, spectral, and temporal resolution required to exploit radio emission from the Sun as a diagnostic of the wide variety of astrophysical processes that occur there. FASR represents a major advance over existing radioheliographs, and is expected to remain the world's premier solar radio instrument for two decades or more after completion. FASR will be a versatile and powerful instrument, providing unique data to a broad users community. Solar, solar-terrestrial, and space physicists will exploit FASR to attack a broad science program, including problems of fundamental interest: coronal magnetography, solar flares and particle acceleration, drivers of space weather, and the thermal structure and dynamics of the solar atmosphere. A design study and implementation planning are underway. Recent progress is reviewed here.

  5. Solar energy modulator

    Science.gov (United States)

    Hale, R. R. (Inventor); Mcdougal, A. R.

    1984-01-01

    A module is described with a receiver having a solar energy acceptance opening and supported by a mounting ring along the optic axis of a parabolic mirror in coaxial alignment for receiving solar energy from the mirror, and a solar flux modulator plate for varying the quantity of solar energy flux received by the acceptance opening of the module. The modulator plate is characterized by an annular, plate-like body, the internal diameter of which is equal to or slightly greater than the diameter of the solar energy acceptance opening of the receiver. Slave cylinders are connected to the modulator plate for supporting the plate for axial displacement along the axis of the mirror, therby shading the opening with respect to solar energy flux reflected from the surface of the mirror to the solar energy acceptance opening.

  6. Photovoltaic solar cell

    Science.gov (United States)

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2015-09-08

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  7. Photovoltaic solar concentrator

    Science.gov (United States)

    Nielson, Gregory N.; Okandan, Murat; Resnick, Paul J.; Cruz-Campa, Jose Luis

    2012-12-11

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  8. Narrow grass hedges reduce tylosin and associated antimicrobial resistance genes in agricultural runoff

    Science.gov (United States)

    Agricultural runoff from areas receiving livestock manure can potentially contaminate surface water with antimicrobials and antimicrobial resistance genes (ARGs). The objective of this study was to investigate the effectiveness of narrow grass hedges (NGHs) on reducing the transport of antimicrobial...

  9. Narrow Wavelength, Frequency Modulated Source at 1.5mm Wavelength, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for Lidar applications. The laser should be tunable by several nm and frequency modulated...

  10. Quantum statistics of the gain-narrowed Raman linewidth in H2

    International Nuclear Information System (INIS)

    Swanson, R.C.; Battle, P.R.; Carlsten, J.L.

    1990-01-01

    Recent studies have shown that single-shot spectra in stimulated Raman scattering can be much narrower than the quantum-mechanical gain-narrowed linewidth. However, shot-to-shot fluctuations in the single-shot spectra are such that the ensemble average gives the gain-narrowed linewidth. This happens because the mean frequencies of the single-shot spectra fluctuate from shot to shot under the gain-narrowed linewidth, and because some ''noisy'' shots are broadened or display multipeaked spectra. The nature of these quantum-noise-initiated fluctuations will be discussed in this paper, with both numerical and experimental results presented. Noisy, multipeaked, single-shot spectra will be shown to have a broader distribution of mean frequencies than the distribution of near-Fourier-transform-limited spectra

  11. Occurrence and Global Properties of Narrow CIV lambda 1549 Absorption Lines in Moderate-Redshift Quasars

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2003-01-01

    A statistical study is presented of (a) the frequency of narrow CIV lambda 1549 absorption lines in 1.5 ~50%) of narrow CIV absorbers is detected for the radio-quiet and radio-loud quasars, and a constant ~25% of all the quasars, irrespective of radio type display associated CIV absorbers stronger...... than a rest equivalent width of 0.5A. Both radio-quiet and radio-loud quasars with narrow absorption lines have systematically redder continua, especially strongly absorbed objects. There is evidence of inclination dependent dust reddening and absorption for the radio quasars. An additional key result...... is that the most strongly absorbed radio quasars have the largest radio source extent. This result is in stark contrast to a recent study of the low-frequency selected Molonglo survey in which a connection between the strength of the narrow absorbers and the (young) age of the radio source has been proposed...

  12. Metal-framed partitions with reduced thicknesses. Part 1: Narrower studs and cavities

    Science.gov (United States)

    Plumb, G. D.

    The sound insulations were measured, in the Research Department Transmission Suite, of ten different metal-framed partitions. These partitions had narrower cavities and metal studs than those of the conventional thickness metal-framed Camden. Mineral wool had been installed in the cavities of some of the partitions and some partitions had double plasterboard skins rather than plasterboard-fiberboard skins. The sound insulations of these narrow partitions were generally comparable with, or marginally higher than, those of similar partitions, having stud and cavity widths equal to those in the conventional thickness metal-framed Camden. However, the loadbearing capabilities must be investigated before these narrow partitions can be recommended as alternatives to the conventional thickness metal-framed Camden. The use of these narrow partitions should result in average increases, of approximately 8%, in the available floor areas of typical studios.

  13. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  14. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  15. Difficulties of supercurrents in narrow pores of 3He-A

    International Nuclear Information System (INIS)

    Thuneberg, E.V.; Kurkijaervi, J.

    1980-01-01

    We consider resistanceless supercurrents through narrow pores and find such currents to vanish in most cases because of end effects at the entries and exists of the pores. Under pressure dc-supercurrents are found to arise. (author)

  16. Spectral design of temperature-invariant narrow bandpass filters for the mid-infrared

    DEFF Research Database (Denmark)

    Stolberg-Rohr, Thomine Kirstine; Hawkins, Gary J.

    2015-01-01

    The ability of narrow bandpass filters to discriminatewavelengths between closely-separated gas absorption lines is crucial inmany areas of infrared spectroscopy. As improvements to the sensitivity ofinfrared detectors enables operation in uncontrolled high-temperature environments, this imposes ...

  17. Nimbus-7 Narrow Field of View (NFOV) Maximum Likelihood Cloud Estimation (MLCE) Data in Native Format

    Data.gov (United States)

    National Aeronautics and Space Administration — NIMBUS7_NFOV_MLCE data are Nimbus 7 Narrow Field of View (NFOV) Maximum Likelihood Cloud Estimation (MLCE) Data in Native Format.The NIMBUS7_NFOV_MLCE data set uses...

  18. Simultaneous wide and narrow QRS complex tachycardia: what is the mechanism?

    NARCIS (Netherlands)

    Rodriguez-Manero, M.; Bayrak, F.; Namdar, M.; Casado-Arroyo, R.; Ricciardi, D.; Chierchia, G.B.; Sarkozy, A.; Asmundis, C. de; Brugada, P.

    2013-01-01

    We present the case of a 50-year-old patient with several episodes of syncope and documented simultaneous wide and narrow QRS complex tachycardia. We then review this tacharrhythmia, focusing on electrophysiological findings and pathophysiology, diagnosis and treatment.

  19. Large Format Narrow Band High Throughput Optical Filters for 0.5-2.75 Project

    Data.gov (United States)

    National Aeronautics and Space Administration — One of the most efficient ways to create narrow band filter is the use of reflective Bragg gratings or which allow increasing of efficiency and decreasing of weight...

  20. The effect of divided attention on emotion-induced memory narrowing.

    Science.gov (United States)

    Mickley Steinmetz, Katherine R; Waring, Jill D; Kensinger, Elizabeth A

    2014-01-01

    Individuals are more likely to remember emotional than neutral information, but this benefit does not always extend to the surrounding background information. This memory narrowing is theorised to be linked to the availability of attentional resources at encoding. In contrast to the predictions of this theoretical account, altering participants' attentional resources at encoding by dividing attention did not affect emotion-induced memory narrowing. Attention was divided using three separate manipulations: a digit ordering task (Experiment 1), an arithmetic task (Experiment 2) and an auditory discrimination task (Experiment 3). Across all three experiments, divided attention decreased memory across the board but did not affect the degree of memory narrowing. These findings suggest that theories to explain memory narrowing must be expanded to include other potential mechanisms beyond the limitations of attentional resources.

  1. The transition time induced narrow linewidth of the electromagnetically induced transparency in caesium vapour

    International Nuclear Information System (INIS)

    Li Luming; Peng Xiang; Liu Cheng; Guo Hong; Chen Xuzong

    2004-01-01

    We observed a narrow linewidth (∼60 kHz) in a Doppler-broadened system showing electromagnetically induced transparency in caesium atomic vapour. The transition time induced reduction of the linewidth is illustrated both theoretically and experimentally

  2. The treatment of open- and narrow-angle glaucoma | Sevel | South ...

    African Journals Online (AJOL)

    Abstract. A review of the presentation and diagnosis of acute narrow- angle glaucoma and open-angle glaucoma is presented. Both medical and surgical treatment are discllssed with anevaluation of operative techniques.

  3. NMR line narrowing experiments with large resonance offset for the study of solids

    International Nuclear Information System (INIS)

    Mueller, R.; Scheler, G.

    1979-01-01

    Some special, easily realized multipuls sequences with large resonance offset are considered. The line narrowing of these sequences is sufficient for many applications. The fundamental physical properties are discussed and first experimental results are described. (author)

  4. Narrow duplicated internal auditory canal: radiological findings and review of the literature

    International Nuclear Information System (INIS)

    Demir, Oezguen Ilhan; Cakmakci, Handan; Men, Sueleyman; Erdag, Taner Kemal

    2005-01-01

    Narrow duplicated internal auditory canal (IAC) is a rare malformation of the temporal bone that is associated with ipsilateral congenital sensorineural hearing loss. This may be an isolated finding or a part of a syndrome. Radiological examination should demonstrate aplasia or hypoplasia of the neural components of the narrow IAC, to guide the surgical approach. We report a 7-year-old boy with Klippel-Feil syndrome with a narrow double IAC with no sensorineural hearing loss but with conductive hearing loss. In this patient, the IAC consisted of two separate narrow bony canals clearly seen on 3D temporal bone CT and one nerve that was delineated on MRI. The contralateral external auditory canal was stenotic and the ossicles were dysplastic. (orig.)

  5. Spark PRM: Using RRTs within PRMs to efficiently explore narrow passages

    KAUST Repository

    Shi, Kensen

    2014-05-01

    © 2014 IEEE. Probabilistic RoadMaps (PRMs) have been successful for many high-dimensional motion planning problems. However, they encounter difficulties when mapping narrow passages. While many PRM sampling methods have been proposed to increase the proportion of samples within narrow passages, such difficult planning areas still pose many challenges. We introduce a novel algorithm, Spark PRM, that sparks the growth of Rapidly-expanding Random Trees (RRTs) from narrow passage samples generated by a PRM. The RRT rapidly generates further narrow passage samples, ideally until the passage is fully mapped. After reaching a terminating condition, the tree stops growing and is added to the roadmap. Spark PRM is a general method that can be applied to all PRM variants. We study the benefits of Spark PRM with a variety of sampling strategies in a wide array of environments. We show significant speedups in computation time over RRT, Sampling-based Roadmap of Trees (SRT), and various PRM variants.

  6. Narrow Wavelength, Frequency Modulated Source at 1.5 Wavelength, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Ultrastable, narrow linewidth, tunable, high reliability sources at 1.5 or 2mm are needed for high performance LIDARs for several NASA applications, including wind...

  7. Comparing auditory brainstem responses (ABRs) to toneburst and narrow band CE-chirp in young infants.

    Science.gov (United States)

    Rodrigues, Gabriela Ribeiro Ivo; Ramos, Natália; Lewis, Doris Ruthi

    2013-09-01

    The difference of characteristics (latency and amplitude) between toneburst and narrow CE-chirp stimuli on ABR recording was analyzed in normal hearing infants. 500, 1000, 2000 and 4000 Hz toneburst and narrow band CE-chirp auditory brainstem responses (ABRs) were recorded in 40 normal-hearing infants. The amplitude and latency parameters of the ABR were collected for each of the four stimulus levels: 80, 60, 40, and 20 dB nHL. Both stimuli started from 80 dB nHL using alternating polarity and the rates were both 27.1/s. The toneburst latencies are greater than narrow band CE-chirp latencies for all intensities at 500, 1000 and 2000 Hz (p Hz this difference was not significant. At 500 Hz, wave V amplitude is larger for toneburst than narrow CE-chirp (p Hz there is no difference between the wave V toneburst and narrow band CE-chirp amplitudes at 80 dB nHL (p = 0.940; p = 0.776 and p = 0.217 respectively). On the other hand, in the levels to 60, 40 and 20 dB nHL, narrow band CE-chirp amplitudes are larger than toneburst amplitude (p < 0.001). Narrow band CE-chirp ABRs generates shorter latencies than the toneburst ABRs, especially to low frequencies. Higher amplitudes were found with narrow band CE-chirp stimuli for all frequencies tested, except to high levels. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Elongational viscosity of narrow molar mass distribution polystyrene. A Bach, K. Almdal, H.K. Rasmussen and O. Hassager

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Bach, Anders; Almdal, Kristoffer

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distributin polystyrene melts ......Transient and steady elongational viscosity has been measured for two narrow molar mass distributin polystyrene melts ...

  9. Solar engineering of thermal processes

    CERN Document Server

    Duffie, John A

    2013-01-01

    The updated fourth edition of the ""bible"" of solar energy theory and applications Over several editions, Solar Engineering of Thermal Processes has become a classic solar engineering text and reference. This revised Fourth Edition offers current coverage of solar energy theory, systems design, and applications in different market sectors along with an emphasis on solar system design and analysis using simulations to help readers translate theory into practice. An important resource for students of solar engineering, solar energy, and alternative energy as well

  10. Solar energy guide

    International Nuclear Information System (INIS)

    Lentz, A.; Winter, R.

    1993-07-01

    Many aspects with regard to the practical use of solar energy are discussed. This guide is aimed at informing local and regional administrators, committee members of housing corporations and public utilities and public relations officers on the possibilities to use solar energy. In chapter one an overview is given of the use of solar energy in the housing sector, the recreational sector, agricultural sector, industry, trade and other sectors. In the chapters two, three and four attention is paid to passive solar energy, active thermal solar energy and photovoltaic energy respectively. In the chapters five and six aspects concerning the implementation of solar energy systems in practice are discussed. First an outline of the parties involved in implementing solar energy is given: the municipality, the energy utility, the province, local authorities, advisors, housing constructors and the occupants of the buildings. Then attention is paid to the consequences of implementing solar energy for the building inspection and regulations, the finances, energy savings and the environment. In chapter seven an overview is given of the subsidy regulations of the European Community, the Dutch national and local governments. Chapter contains addresses of solar thermal systems, photovoltaic systems and other institutes operating in the field of solar energy, as well as the titles of a number of brochures and courses. 51 figs., 7 tabs., 86 refs

  11. National Community Solar Platform

    Energy Technology Data Exchange (ETDEWEB)

    Rupert, Bart [Clean Energy Collective, Louisville, CO (United States)

    2016-06-30

    This project was created to provide a National Community Solar Platform (NCSP) portal known as Community Solar Hub, that is available to any entity or individual who wants to develop community solar. This has been done by providing a comprehensive portal to make CEC’s solutions, and other proven community solar solutions, externally available for everyone to access – making the process easy through proven platforms to protect subscribers, developers and utilities. The successful completion of this project provides these tools via a web platform and integration APIs, a wide spectrum of community solar projects included in the platform, multiple groups of customers (utilities, EPCs, and advocates) using the platform to develop community solar, and open access to anyone interested in community solar. CEC’s Incubator project includes web-based informational resources, integrated systems for project information and billing systems, and engagement with customers and users by community solar experts. The combined effort externalizes much of Clean Energy Collective’s industry-leading expertise, allowing third parties to develop community solar without duplicating expensive start-up efforts. The availability of this platform creates community solar projects that are cheaper to build and cheaper to participate in, furthering the goals of DOE’s SunShot Initiative. Final SF 425 Final SF 428 Final DOE F 2050.11 Final Report Narrative

  12. The large scale and long term evolution of the solar wind speed distribution and high speed streams

    International Nuclear Information System (INIS)

    Intriligator, D.S.

    1977-01-01

    The spatial and temporal evolution of the solar wind speed distribution and of high speed streams in the solar wind are examined. Comparisons of the solar wind streaming speeds measured at Earth, Pioneer 11, and Pioneer 10 indicate that between 1 AU and 6.4 AU the solar wind speed distributions are narrower (i.e. the 95% value minus the 5% value of the solar wind streaming speed is less) at extended heliocentric distances. These observations are consistent with one exchange of momentum in the solar wind between high speed streams and low speed streams as they propagate outward from the Sun. Analyses of solar wind observations at 1 AU from mid 1964 through 1973 confirm the earlier results reported by Intriligator (1974) that there are statistically significant variations in the solar wind in 1968 and 1969, years of solar maximum. High speed stream parameters show that the number of high speed streams in the solar wind in 1968 and 1969 is considerably more than the predicted yearly average, and in 1965 and 1972 less. Histograms of solar wind speed from 1964 through 1973 indicate that in 1968 there was the highest percentage of elevated solar wind speeds and in 1965 and 1972 the lowest. Studies by others also confirm these results although the respective authors did not indicate this fact. The duration of the streams and the histograms for 1973 imply a shifting in the primary stream source. (Auth.)

  13. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    Directory of Open Access Journals (Sweden)

    M. Norhafana

    2015-11-01

    Full Text Available Solar water heating systems is one of the applications of solar energy. One of the components of a solar water heating system is a solar collector that consists of an absorber. The performance of the solar water heating system depends on the absorber in the solar collector. In countries with unsuitable weather conditions, the indoor testing of solar collectors with the use of a solar simulator is preferred. Thus, this study is conducted to use a multilayered absorber in the solar collector of a solar water heating system as well as to evaluate the performance of the solar collector in terms of useful heat of the multilayered absorber using the multidirectional ability of a solar simulator at several values of solar radiation. It is operated at three variables of solar radiation of 400 W/m2, 550 W/m2 and 700 W/m2 and using three different positions of angles at 0º, 45º and 90º. The results show that the multilayer absorber in the solar collector is only able to best adapt at 45° of solar simulator with different values of radiation intensity. At this angle the maximum values of useful heat and temperature difference are achieved. KEYWORDS: solar water heating system; solar collector; multilayered absorber; solar simulator; solar radiation 

  14. 78 FR 43868 - Notice of Intent To Prepare a Draft Environmental Impact Statement for the Whittier Narrows Dam...

    Science.gov (United States)

    2013-07-22

    ... Prepare a Draft Environmental Impact Statement for the Whittier Narrows Dam Safety Modification Study... Narrows Dam Safety Modification Study (DSMS). Whittier Narrows Dam is located approximately 12 miles east... safety concerns such as dam settling, seismic damages, and seepage. The DSMS will identify risk reduction...

  15. 75 FR 15458 - Request for Small Reclamation Projects Act Loan To Construct Narrows Dam in Sanpete County, UT

    Science.gov (United States)

    2010-03-29

    ... Projects Act Loan To Construct Narrows Dam in Sanpete County, UT AGENCY: Bureau of Reclamation, Interior... construction by SWCD of the proposed Narrows Dam and reservoir, a non-Federal project to be located on... construction of the 17,000 acre-foot Narrows Dam and reservoir on Gooseberry Creek, pipelines to deliver the...

  16. Solar Thermal Energy; Energia Solar Termica

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Martinez, M.; Cuesta-Santianes, M. J.; Cabrera Jimenez, J. A.

    2008-07-01

    Approximately, 50 % of worldwide primary energy consumption is done in the form of heat in applications with a temperature lower than 250 degree centigree (low-medium temperature heat). These data clearly demonstrate the great potential of solar thermal energy to substitute conventional fossil fuels, which are becoming more expensive and are responsible for global warming. Low-medium temperature solar thermal energy is mainly used to obtain domestic hot water and provide space heating. Active solar thermal systems are those related to the use of solar thermal collectors. This study is dealing with low temperature solar thermal applications, mainly focusing on active solar thermal systems. This kind of systems has been extensively growing worldwide during the last years. At the end of 2006, the collector capacity in operation worldwide equalled 127.8 GWth. The technology is considered to be already developed and actions should be aimed at favouring a greater market penetration: diffusion, financial support, regulations establishment, etc. China and USA are the leading countries with a technology based on evacuated tube collectors and unglazed collectors, respectively. The rest of the world markets are dominated by the flat glazed collectors technology. (Author) 15 refs.

  17. Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

    Science.gov (United States)

    Wilcox, Brian H.

    2012-01-01

    Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by

  18. Path Minima Queries in Dynamic Weighted Trees

    DEFF Research Database (Denmark)

    Davoodi, Pooya; Brodal, Gerth Stølting; Satti, Srinivasa Rao

    2011-01-01

    update time?} in the comparison and the RAM models. These structures also support inserting a node on an edge, inserting a leaf, and contracting edges. When only insertion and deletion of leaves are desired, we give data structures in the comparison and the RAM models, with optimal query time...

  19. Maxima and Minima in Fuzzified Linear Orderings

    Czech Academy of Sciences Publication Activity Database

    Běhounek, Libor

    2016-01-01

    Roč. 289, 15 April (2016), s. 82-93 ISSN 0165-0114 R&D Projects: GA ČR GPP103/10/P234; GA MŠk ED1.1.00/02.0070 Grant - others:GA MŠk(CZ) EE2.3.30.0010 Institutional support: RVO:67985807 Keywords : fuzzy relations * similarity relations * fuzzy orderings * higher-order fuzzy logic Subject RIV: BA - General Mathematics Impact factor: 2.718, year: 2016

  20. Het zorggebruik van minima in Amsterdam

    NARCIS (Netherlands)

    Dijkshoorn, H.; Hazeleger, F. G. M.; de Jong, I. M.; van der Lee, A. P. M.; Kunst, A. E.

    2016-01-01

    Gaining more insight into any differences in care expenses between minimum and higher income groups. Cross-sectional study among 6,709 citizens of Amsterdam aged 19 years and over. Data on declared health care expenses from 2012 were linked to personal income and to public health survey data.

  1. Evolution of the solar irradiance during the Holocene

    Science.gov (United States)

    Vieira, L. E. A.; Solanki, S. K.; Krivova, N. A.; Usoskin, I.

    2011-07-01

    moment are significantly lower at earlier times than the reconstructions based on the virtual dipole moment. We also present a combined reconstruction, which represents our best estimate of total solar irradiance for any given time during the Holocene. Conclusions: We present the first physics-based reconstruction of the total solar irradiance over the Holocene, which will be of interest for studies of climate change over the last 11 500 years. The reconstruction indicates that the decadally averaged total solar irradiance ranges over approximately 1.5 W/m2 from grand maxima to grand minima. Appendix A is available in electronic form at http://www.aanda.orgThe TSI data is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A6

  2. Solar opacities constrained by solar neutrinos and solar oscillations

    International Nuclear Information System (INIS)

    Cox, A.N.

    1989-01-01

    This review discusses the current situation for opacities at the solar center, the solar surface, and for the few million kelvin temperatures that occur below the convection zone. The solar center conditions are important because they are crucial for the neutrino production, which continues to be predicted about 4 times that observed. The main extinction effects there are free-free photon absorption in the electric fields of the hydrogen, helium and the CNO atoms, free electron scattering of photons, and the bound-free and bound-bound absorption of photons by iron atoms with two electrons in the 1s bound level. An assumption that the iron is condensed-out below the convection zone, and the opacity in the central regions is thereby reduced, results in about a 25 percent reduction in the central opacity but only a 5 percent reduction at the base of the convection zone. Furthermore, the p-mode solar oscillations are changed with this assumption, and do not fit the observed ones as well as for standard models. A discussion of the large effective opacity reduction by weakly interacting massive particles also results in poor agreement with observed p-mode oscillation frequencies. The much larger opacities for the solar surface layers from the Los Alamos Astrophysical Opacity Library instead of the widely used Cox and Tabor values show small improvements in oscillation frequency predictions, but the largest effect is in the discussion of p-mode stability. Solar oscillation frequencies can serve as an opacity experiment for the temperatures and densities, respectively, of a few million kelvin and between 0.1 and 10 g/cm 3 . Current oscillation frequency calculations indicate that possibly the Opacity Library values need an increase of typically 15 percent just at the bottom of the convection zone at 3 x 10 6 K. 41 refs., 15 figs., 1 tab

  3. Solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L.

    2007-09-18

    A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  4. Solar panel cleaning robot

    Science.gov (United States)

    Nalladhimmu, Pavan Kumar Reddy; Priyadarshini, S.

    2018-04-01

    As the demand of electricity is increasing, there is need to using the renewable sources to produce the energy at present of power shortage, the use of solar energy could be beneficial to great extent and easy to get the maximum efficiency. There is an urgent in improving the efficiency of solar power generation. Current solar panels setups take a major power loss when unwanted obstructions cover the surface of the panels. To make solar energy more efficiency of solar array systems must be maximized efficiency evaluation of PV panels, that has been discussed with particular attention to the presence of dust on the efficiency of the PV panels have been highlighted. This paper gives the how the solar panel cleaning system works and designing of the cleaning system.

  5. Climate Fundamentals for Solar Heating.

    Science.gov (United States)

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    The design of any solar heating system is influenced heavily by climate; in this bulletin, information on climate as related to solar heating is as related to solar heating is provided. Topics discussed include: (1) solar radiation; (2) degree days; (3) climate and calculations which make use of solar radiation and degree days; and (4)…

  6. Solar Renewable Energy. Teaching Unit.

    Science.gov (United States)

    Buchanan, Marion; And Others

    This unit develops the concept of solar energy as a renewable resource. It includes: (1) an introductory section (developing understandings of photosynthesis and impact of solar energy); (2) information on solar energy use (including applications and geographic limitations of solar energy use); and (3) future considerations of solar energy…

  7. SOLAR EFFECTS ON BUILDING DESIGN.

    Science.gov (United States)

    Building Research Inst., Inc., Washington, DC.

    A REPORT OF A PROGRAM HELD AS PART OF THE BUILDING RESEARCH INSTITUTE 1962 SPRING CONFERENCE ON THE SOLAR EFFECTS ON BUILDING DESIGN. TOPICS DISCUSSED ARE--(1) SOLAR ENERGY DATA APPLICABLE TO BUILDING DESIGN, (2) THERMAL EFFECTS OF SOLAR RADIATION ON MAN, (3) SOLAR EFFECTS ON ARCHITECTURE, (4) SOLAR EFFECTS ON BUILDING COSTS, (5) SELECTION OF…

  8. Solar energy emplacement developer

    Science.gov (United States)

    Mortensen, Michael; Sauls, Bob

    1991-01-01

    A preliminary design was developed for a Lunar Power System (LPS) composed of photovoltaic arrays and microwave reflectors fabricated from lunar materials. The LPS will collect solar energy on the surface of the Moon, transform it into microwave energy, and beam it back to Earth where it will be converted into usable energy. The Solar Energy Emplacement Developer (SEED) proposed will use a similar sort of solar energy collection and dispersement to power the systems that will construct the LPS.

  9. Solar photocatalyzed process economics

    International Nuclear Information System (INIS)

    Link, H.

    1990-01-01

    This paper describes the Solar Energy Research Institute (SERI) cost estimates for solar water detoxification systems based on the best available information as of October 1990. Comparative costs are also provided for competitive conventional technologies which are presently applied in the water detoxification market. Although costs for solar photocatalytic systems are presently higher than those of competitive technologies, cost and performance improvements should lead to cost competitiveness by 1995

  10. Solar Asset Management Software

    Energy Technology Data Exchange (ETDEWEB)

    Iverson, Aaron [Ra Power Management, Inc., Oakland, CA (United States); Zviagin, George [Ra Power Management, Inc., Oakland, CA (United States)

    2016-09-30

    Ra Power Management (RPM) has developed a cloud based software platform that manages the financial and operational functions of third party financed solar projects throughout their lifecycle. RPM’s software streamlines and automates the sales, financing, and management of a portfolio of solar assets. The software helps solar developers automate the most difficult aspects of asset management, leading to increased transparency, efficiency, and reduction in human error. More importantly, our platform will help developers save money by improving their operating margins.

  11. Profile in solar

    International Nuclear Information System (INIS)

    Cohen, S.; Woods, A.

    1991-01-01

    This article reviews an innovative solar hot water heater and its inventor/entrepreneur. It includes the inventor's strategy for developing and marketing the product and his ideas on the state of the solar industry in general. There is a brief description of the solar water heater which has as prominent features its skylight-like appearance, resistance to freeze damage, simplicity and low cost

  12. Rectenna solar cells

    CERN Document Server

    Moddel, Garret

    2013-01-01

    Rectenna Solar Cells discusses antenna-coupled diode solar cells, an emerging technology that has the potential to provide ultra-high efficiency, low-cost solar energy conversion. This book will provide an overview of solar rectennas, and provide thorough descriptions of the two main components: the diode, and the optical antenna. The editors discuss the science, design, modeling, and manufacturing of the antennas coupled with the diodes. The book will provide concepts to understanding the challenges, fabrication technologies, and materials required to develop rectenna structures. Written by e

  13. Solar and interplanetary disturbances

    CERN Document Server

    Alurkar, S K

    1997-01-01

    Over the last three decades, a spate of solar wind observations have been made with sophisticated ground-based and space-borne instruments. Two highly successful space missions of the Skylab and the twin spacecraft Helios 1 and 2 have amassed an invaluable wealth of information on the large scale structure of the inner heliosphere, the solar and interplanetary magnetic field, coronal holes, interplanetary dust, solar windflows, etc.Solar and interplanetary propagating phenomena have been extensively studied during the last two decades. Very recently, a new simple model based on results from a

  14. CERN... Solar Style

    CERN Multimedia

    2001-01-01

    Inventor William van Sprolant presenting the Solar Club's latest invention, the solar fountain. The CERN Solar Club is giving new meaning to the phrase 'fun in the sun' with their most recently developed contraption, the Solar Fountain. The Fountain was presented to the public just outside of Restaurant 1 on Wednesday October, 17th and uses solar energy to run a water pump at its base to propel a golden plastic ball up into the air. As lovely as the fountain is, the funny thing about it is that the height of the water jet and the ball are an artistic method of measuring the amount of solar power being captured by the photovoltaique panel (no batteries included). The day it was presented started out cloudy, but as the afternoon wore on, the weather brightened and the fountain jumped to life. William van Sprolant, the Solar Fountain's inventor, had great fun with the fountain in front of a group of visiting children swiveling the solar panel in multiple directions. 'Everyone who installs solar panels worrie...

  15. Solar Cycle Predictions

    Science.gov (United States)

    Pesnell, William Dean

    2012-01-01

    Solar cycle predictions are needed to plan long-term space missions; just like weather predictions are needed to plan the launch. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory as you consume the reduced propellant load more rapidly. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Solar cycle predictions also anticipate the shortwave emissions that cause degradation of solar panels. Testing solar dynamo theories by quantitative predictions of what will happen in 5-20 years is the next arena for solar cycle predictions. A summary and analysis of 75 predictions of the amplitude of the upcoming Solar Cycle 24 is presented. The current state of solar cycle predictions and some anticipations how those predictions could be made more accurate in the future will be discussed.

  16. Harnessing solar heat

    CERN Document Server

    Norton, Brian

    2013-01-01

    Systems engineered by man to harness solar heat in a controlled manner now include a diverse range of technologies each serving distinctive needs in particular climate contexts. This text covers the breadth of solar energy technologies for the conversion of solar energy to provide heat, either as the directly-used output or as an intermediary to other uses such as power generation or cooling. It is a wholly updated, extended and revised version of “Solar Energy Thermal Technology” first published in 1992. The text draws on the own author’s research and that of numerous colleagues and

  17. Solar neutrino experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hampel, W. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    1996-11-01

    The present status of experimental solar neutrino research is reviewed. Updated results from the Homestake, Kamiokande, GALLEX and SAGE detectors all show a deficit when compared to recent standard solar model calculations. Two of these detectors, GALLEX and SAGE, have recently been checked with artificial {sup 51}Cr neutrino sources. It is shown that astrophysical scenarios to solve the solar neutrino problems are not favoured by the data. There is hope that the results of forthcoming solar neutrino experiments can provide the answers to the open questions. (author) 6 figs., 3 tabs., 36 refs.

  18. 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

  19. Solar Cooker Technological Change

    DEFF Research Database (Denmark)

    Ahmad, Bashir

    1997-01-01

    The challenges which solar cooking technology is facing right now is discussed. Based on a field study in Madras and Gujarat, it is asserted that there is an important incompatibility between the technology and the every day real-life conditions of the "users" of solar cooker. An evaluation report...... on a solar cooker technology in Burkina Faso supports the findings of the study. It is concluded that the users and other important actors have to be incorporated in the technological development process of solar cookers in the future....

  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. Long Island Solar Farm

    Energy Technology Data Exchange (ETDEWEB)

    Anders, R.

    2013-05-01

    The Long Island Solar Farm (LISF) is a remarkable success story, whereby very different interest groups found a way to capitalize on unusual circumstances to develop a mutually beneficial source of renewable energy. The uniqueness of the circumstances that were necessary to develop the Long Island Solar Farm make it very difficult to replicate. The project is, however, an unparalleled resource for solar energy research, which will greatly inform large-scale PV solar development in the East. Lastly, the LISF is a superb model for the process by which the project developed and the innovation and leadership shown by the different players.

  2. 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.)

  3. Passive solar technology

    Energy Technology Data Exchange (ETDEWEB)

    Watson, D

    1981-04-01

    The present status of passive solar technology is summarized, including passive solar heating, cooling and daylighting. The key roles of the passive solar system designer and of innovation in the building industry are described. After definitions of passive design and a summary of passive design principles are given, performance and costs of passive solar technology are discussed. Passive energy design concepts or methods are then considered in the context of the overall process by which building decisions are made to achieve the integration of new techniques into conventional design. (LEW).

  4. THE BALDWIN EFFECT IN THE NARROW EMISSION LINES OF ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Wang, Ting-Gui; Dong, Xiao-Bo [Key Laboratory for Research in Galaxies and Cosmology, The University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Gaskell, C. Martin, E-mail: zkdtc@mail.ustc.edu.cn, E-mail: twang@ustc.edu.cn, E-mail: xbdong@ustc.edu.cn, E-mail: martin.gaskell@uv.cl [Centro de Astrofisica de Valparaiso y Departamento de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Valparaiso (Chile)

    2013-01-01

    The anti-correlations between the equivalent widths of emission lines and the continuum luminosity in active galactic nuclei (AGNs), known as the Baldwin effect, are well established for broad lines, but are less well studied for narrow lines. In this paper we explore the Baldwin effect of narrow emission lines over a wide range of ionization levels and critical densities using a large sample of broad-line, radio-quiet AGNs taken from Sloan Digital Sky Survey Data Release 4. These type 1 AGNs span three orders of magnitude in continuum luminosity. We show that most narrow lines show a similar Baldwin effect slope of about -0.2, while the significant deviations of the slopes for [N II] {lambda}6583, [O II] {lambda}3727, [Ne V] {lambda}3425, and the narrow component of H{alpha} can be explained by the influence of metallicity, star formation contamination, and possibly by the difference in the shape of the UV-optical continuum. The slopes do not show any correlation with either the ionization potential or the critical density. We show that a combination of 50% variations in continuum near 5100 A and a lognormal distribution of observed luminosity can naturally reproduce a constant Baldwin effect slope of -0.2 for all narrow lines. The variations of the continuum could be due to variability, intrinsic anisotropic emission, or an inclination effect.

  5. Solar Public Observations in Japan

    Science.gov (United States)

    Yaji, K.

    2002-01-01

    Now in Japan, there are more than fifty astronomical educational facilities which have solar telescopes, for example, public observatories and science museums. Because many of the solar telescopes have H-alpha filters, such active chromospheric phenomena as solar flares and prominences are easily presented to the public. Though the objects of these solar telescopes must be mainly education and public outreach, they have enough good performance to contribute to solar research. But, the staff in the most of facilities don't know well how to observe the sun and how to understand the solar phenomena. So, we started two attempts in order to support their solar observations. One is the administration of the "Solar Telescope Mailing List (solnet ML)". The purpose is exchanges of information on solar daily phenomena, instruments of solar telescopes, and solar articles. Almost one hundred solar observers use actively this mailing list. The other is the arrangement of the "Solar Telescope Workshop", which were held in 2000 and 2001. These workshops provide a chance for staff in public observational facilities to study observational methods, to learn educational techniques using solar observations, and to show their observational results on solar active phenomena. These two attempts also play a role to link public observers with professional solar researchers. In this presentation, we review the current situation of public solar observations in Japan and introduce solar images observed with the public educational facilities. In addition, we would like to mention what we hope for professional solar researchers.

  6. Parameterization models for solar radiation and solar technology applications

    International Nuclear Information System (INIS)

    Khalil, Samy A.

    2008-01-01

    Solar radiation is very important for the evaluation and wide use of solar renewable energy systems. The development of calibration procedures for broadband solar radiation photometric instrumentation and the improvement of broadband solar radiation measurement accuracy have been done. An improved diffuse sky reference and photometric calibration and characterization software for outdoor pyranometer calibrations are outlined. Parameterizations for direct beam, total hemispherical and diffuse sky radiation and solar radiation technology are briefly reviewed. The uncertainties for various broadband solar radiations of solar energy and atmospheric effects are discussed. The varying responsivities of solar radiation with meteorological, statistical and climatological parameters and possibility atmospheric conditions was examined

  7. Reconstruction of total and spectral solar irradiance from 1974 to 2013 based on KPVT, SoHO/MDI, and SDO/HMI observations

    Science.gov (United States)

    Yeo, K. L.; Krivova, N. A.; Solanki, S. K.; Glassmeier, K. H.

    2014-10-01

    Context. Total and spectral solar irradiance are key parameters in the assessment of solar influence on changes in the Earth's climate. Aims: We present a reconstruction of daily solar irradiance obtained using the SATIRE-S model spanning 1974 to 2013 based on full-disc observations from the KPVT, SoHO/MDI, and SDO/HMI. Methods: SATIRE-S ascribes variation in solar irradiance on timescales greater than a day to photospheric magnetism. The solar spectrum is reconstructed from the apparent surface coverage of bright magnetic features and sunspots in the daily data using the modelled intensity spectra of these magnetic structures. We cross-calibrated the various data sets, harmonizing the model input so as to yield a single consistent time series as the output. Results: The model replicates 92% (R2 = 0.916) of the variability in the PMOD TSI composite including the secular decline between the 1996 and 2008 solar cycle minima. The model also reproduces most of the variability in observed Lyman-α irradiance and the Mg II index. The ultraviolet solar irradiance measurements from the UARS and SORCE missions are mutually consistent up to about 180 nm before they start to exhibit discrepant rotational and cyclical variability, indicative of unresolved instrumental effects. As a result, the agreement between model and measurement, while relatively good below 180 nm, starts to deteriorate above this wavelength. As with earlier similar investigations, the reconstruction cannot reproduce the overall trends in SORCE/SIM SSI. We argue, from the lack of clear solar cycle modulation in the SIM record and the inconsistency between the total flux recorded by the instrument and TSI, that unaccounted instrumental trends are present. Conclusions: The daily solar irradiance time series is consistent with observations from multiple sources, demonstrating its validity and utility for climate models. It also provides further evidence that photospheric magnetism is the prime driver of

  8. Make Your Own Solar Panel.

    Science.gov (United States)

    Suzuki, David

    1992-01-01

    Presents an activity in which students make a simulated solar panel to learn about the principles behind energy production using solar panels. Provides information about how solar panels function to produce energy. (MCO)

  9. Surface Meteorology and Solar Energy

    Data.gov (United States)

    National Aeronautics and Space Administration — Surface Meteorology and Solar Energy data - over 200 satellite-derived meteorology and solar energy parameters, monthly averaged from 22 years of data, global solar...

  10. Solar Neutrons and Related Phenomena

    CERN Document Server

    Dorman, Lev

    2010-01-01

    This book presents the first comprehensive compilation and review of the extensive body of experimental and theoretical material on solar neutrons and related phenomena published in the scientific literature over the last sixty years. Phenomena related to solar neutrons are more specifically: the decay products of solar neutrons solar gamma rays generated in processes like nuclear reactions between solar energetic charged particles and matter of the solar atmosphere, as well as by the capture of solar neutrons by hydrogen atoms in the solar atmosphere the propagation of solar neutrons, solar gamma rays and other secondary particles through the solar photosphere, chromosphere and corona, as well as through interplanetary space and through the Earth's atmosphere. Models and simulations of particle acceleration, interactions, and propagation processes show that observations of solar neutrons and gamma rays in space and in the Earth's atmosphere yield essential and unique information on the source function of ene...

  11. Solar: California, not dreaming

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.

    2006-03-15

    The California Solar Initiative (CSI) was approved by the California Public Utilities Commission (PUC) in January 2006. The CSI is the largest solar programme of this kind ever in the USA and provides for $3.2 billion in incentives for solar projects between 2007 and 2017. The PUC will oversee a $2.5 billion programme to provide funding for solar installations on commercial and existing residential buildings, while the California Energy Commission (CEC) will manage a separate $350 million fund targeted at new residential building. Existing solar programmes operated by the PUC and CEC will be consolidated into the CSI. The CEC programme will use already allocated funding, but the PUC programme will be funded through revenues collected from customers of the main gas and electric utilities in California. Funds will be distributed via rebates to householders or companies that install solar. As well as solar photovoltaics (PV), rebates will also go to solar thermal power (concentrating solar power) and solar heating and cooling. CSI funding can be used in combination with existing federal tax credits. The aim is a gradual increase from installation of 40 MW of PV in 2005 to 100 MW by 2009. The CSI is also expected to create favourable market conditions for PV manufacturers in California and to encourage investment in production of solar-grade silicon in or near California. Objections from the International Brotherhood of Electrical Workers (IBEW) appear to have been overcome but a number of other potential snags remain. CSI is expected to be replicated in other US states.

  12. HIGH RESOLUTION He i 10830 Å NARROW-BAND IMAGING OF AN M-CLASS FLARE. I. ANALYSIS OF SUNSPOT DYNAMICS DURING FLARING

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ya; Su, Yingna; Hong, Zhenxiang; Ji, Haisheng [Key Laboratory of DMSA, Purple Mountain Observatory, CAS, Nanjing, 210008 (China); Zeng, Zhicheng; Goode, Philip R.; Cao, Wenda [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States); Ji, Kaifan [Yunnan Astronomical Observatories, Kunming 650011 (China)

    2016-12-20

    In this paper, we report our first-step results of high resolution He i 10830 Å narrow-band imaging (bandpass: 0.5 Å) of an M1.8 class two-ribbon flare on 2012 July 5. The flare was observed with the 1.6 m aperture New Solar Telescope at Big Bear Solar Observatory. For this unique data set, sunspot dynamics during flaring were analyzed for the first time. By directly imaging the upper chromosphere, running penumbral waves are clearly seen as an outward extension of umbral flashes; both take the form of absorption in the 10830 Å narrow-band images. From a space–time image made of a slit cutting across a flare ribbon and the sunspot, we find that the dark lanes for umbral flashes and penumbral waves are obviously broadened after the flare. The most prominent feature is the sudden appearance of an oscillating absorption strip inside the ribbon when it sweeps into the sunspot’s penumbral and umbral regions. During each oscillation, outwardly propagating umbral flashes and subsequent penumbral waves rush out into the inwardly sweeping ribbon, followed by a return of the absorption strip with similar speed. We tentatively explain the phenomena as the result of a sudden increase in the density of ortho-helium atoms in the area of the sunspot being excited by the flare’s extreme ultraviolet illumination. This explanation is based on the observation that 10830 Å absorption around the sunspot area gets enhanced during the flare. Nevertheless, questions are still open and we need further well-devised observations to investigate the behavior of sunspot dynamics during flares.

  13. Band-gap narrowing and magnetic behavior of Ni-doped Ba(Ti0.875Ce0.125)O3 thin films

    Science.gov (United States)

    Zhou, Wenliang; Deng, Hongmei; Yu, Lu; Yang, Pingxiong; Chu, Junhao

    2015-11-01

    Band-gap narrowing and magnetic effects have been observed in a Ni-doped Ba(Ti0.875Ce0.125)O3 (BTC) thin film. Structural characterizations and microstructural analysis show that the as-prepared Ba(Ti0.75Ce0.125Ni0.125)O3-δ (BTCN) thin film exhibits a cubic perovskite structure with an average grain size of 25 nm. The Ce doping at the Ti-site results in an increasing perovskite volume to favour an O-vacancy-stabilized Ni2+ substitution. Raman spectroscopy, however, shows the cubic symmetry of crystalline structures is locally lowered by the presence of dopants, significantly deviating from the ideal Pm3m space group. Moreover, BTCN presents a narrowed band-gap, much smaller than that of BaTiO3 and BTC, due to new states of both the highest occupied molecular orbital and the lowest unoccupied molecular orbital in an electronic structure with the presence of Ni. Also, magnetic enhancement driven by co-doping has been confirmed in the films, which mainly stems from the exchange interaction of Ni2+ ions via an electron trapped in a bridging oxygen vacancy. These findings may open an avenue to discover and design optimal perovskite compounds for solar-energy devices and information storage.

  14. Ion-neutral Coupling During Deep Solar Minimum

    Science.gov (United States)

    Huang, Cheryl Y.; Roddy, Patrick A.; Sutton, Eric K.; Stoneback, Russell; Pfaff, Robert F.; Gentile, Louise C.; Delay, Susan H.

    2013-01-01

    The equatorial ionosphere under conditions of deep solar minimum exhibits structuring due to tidal forces. Data from instruments carried by the Communication Navigation Outage Forecasting System (CNOFS) which was launched in April 2008 have been analyzed for the first 2 years following launch. The Planar Langmuir Probe (PLP), Ion Velocity Meter (IVM) and Vector Electric Field Investigation (VEFI) all detect periodic structures during the 20082010 period which appear to be tides. However when the tidal features detected by these instruments are compared, there are distinctive and significant differences between the observations. Tides in neutral densities measured by the Gravity Recovery and Climate Experiment (GRACE) satellite were also observed during June 2008. In addition, Broad Plasma Decreases (BPDs) appear as a deep absolute minimum in the plasma and neutral density tidal pattern. These are co-located with regions of large downward-directed ion meridional velocities and minima in the zonal drifts, all on the nightside. The region in which BPDs occur coincides with a peak in occurrence rate of dawn depletions in plasma density observed on the Defense Meterological Satellite Program (DMSP) spacecraft, as well as a minimum in radiance detected by UV imagers on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) and IMAGE satellites

  15. Astroparticle physics with solar neutrinos

    OpenAIRE

    NAKAHATA, Masayuki

    2011-01-01

    Solar neutrino experiments observed fluxes smaller than the expectations from the standard solar model. This discrepancy is known as the “solar neutrino problem”. Flux measurements by Super-Kamiokande and SNO have demonstrated that the solar neutrino problem is due to neutrino oscillations. Combining the results of all solar neutrino experiments, parameters for solar neutrino oscillations are obtained. Correcting for the effect of neutrino oscillations, the observed neutrino fluxes are consis...

  16. Hysteresis loops of Cosmic Ray intensity decreases versus solar and interplanetary parameters

    Directory of Open Access Journals (Sweden)

    R. P. Kane

    2007-10-01

    Full Text Available The purpose of this study was to examine the correlation between CR (Cosmic Ray intensity and solar, interplanetary and terrestrial parameters. The hysteresis loops of (CR versus those of several solar parameters showed narrow loops in even cycles 20, 22 and broad loops in odd cycles 19, 21, as also in the recent odd cycle 23. Hysteresis plots for CR versus interplanetary number density N and speed V were erratic and uncertain (broad and narrow, all mixed up. Plots of CR versus Interplanetary magnetic field (IMF B seemed to be narrow for even as well as odd cycles. Hysteresis loops between CR and other interplanetary parameters were not clear-cut. The same was true for terrestrial parameters. During sunspot maximum years 2000–2003 of cycle 23, there is a double peak structure in all parameters. Whereas CR have a peak spacing of ~30 months, sunspots and Tilt angle have a spacing of only ~20 months. The solar open magnetic flux and the Voyager 1 magnetic field have a spacing of ~25 months. The solar polar magnetic field reverses later than the first peak of all parameters and hence, could not be a direct cause (as if effect started before the cause and lasted for several months more after the cause disappeared. It seems that CR modulation is mainly guided by magnetic configurations deep in the heliosphere, which may not have a simple relationship with parameters near Earth or near Sun.

  17. Threat but not arousal narrows attention: Evidence from pupil dilation and saccade control

    Directory of Open Access Journals (Sweden)

    Henk eVan Steenbergen

    2011-10-01

    Full Text Available It has been shown that negative affect causes attentional narrowing. According to Easterbrook’s (1959 influential hypothesis this effect is driven by the withdrawal motivation inherent to negative emotions and might be related to increases in arousal. We investigated whether valence-unspecific increases in physiological arousal, as measured by pupil dilation, could account for attentional narrowing effects in a cognitive control task. Following the presentation of a negative, positive, or neutral picture, participants performed a saccade task with a prosaccade versus an antisaccade instruction. The reaction time difference between pro- and antisaccades was used to index attentional selectivity, and while pupil diameter was used as an index of physiological arousal. Pupil dilation was observed for both negative and positive pictures, which indicates increased physiological arousal. However, increased attentional selectivity was only observed following negative pictures. Our data show that motivational intensity effects on attentional narrowing can occur independently of physiological arousal effects.

  18. Sensor based on Fano resonances of plane metamaterial with narrow slits

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wan-Xia, E-mail: kate@mail.ahnu.edu.cn [State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Physics Department, Fudan University, Shanghai 200433 (China); The College of Physics and Electronic Information, Anhui Normal University, Wuhu, Anhui 241000 (China); Guo, Juan-Juan; Wang, Mao-Sheng; Zhao, Guo-Ren [The College of Physics and Electronic Information, Anhui Normal University, Wuhu, Anhui 241000 (China)

    2017-03-11

    The optical properties of a composite metamaterial composed of narrow slits and nano hole pairs have been investigated experimentally and numerically. The strength of the transmission peak originating from the interference between the coupled surface plasmon polaritons (SPP) of the narrow slit and the SPP modes of the hole array is modulated by the degree of symmetry breaking. Some SPP modes can be inhibited by controlling the spacer layer thickness. Our metamaterial has potential applications in sensing and weak signal detection. - Highlights: • The plasmonic nanostructure composed of narrow slits and nano hole pairs were designed. • The optical properties were investigated experimentally and numerically. • The Fano resonances were found on the compound nanostructure. • The results have potential applications in sensing and weak signal detection.

  19. Experimental study on convective boiling heat transfer in narrow-gap annulus tubes

    International Nuclear Information System (INIS)

    Li Bin; Zhao Jianfu; Tang Zemei; Hu Wenrui; Zhou Fangde

    2004-01-01

    Since convective boiling or highly subcooled single-phase forced convection in micro-channels is an effective cooling mechanism with a wide range of applications, more experimental and theoretical studies are required to explain and verify the forced convection heat transfer phenomenon in narrow channels. In this experimental study, authors model the convective boiling behavior of water with low latent heat substance Freon 113 (R-113), with the purpose of saving power consumption and visualizing experiments. Both heat transfer and pressure drop characteristics were measured in subcooled and saturated concentric narrow gap forced convection boiling. Data were obtained to qualitatively identify the effects of gap size, pressure, flow rate and wall superheat on boiling regimes and the transition between various regimes. Some significant differences from unconfined forced convection boiling were found, and also, the flow patterns in narrow vertical annulus tubes have been studied quantitatively. (authors)

  20. Design of narrow band photonic filter with compact MEMS for tunable resonant wavelength ranging 100 nm

    Directory of Open Access Journals (Sweden)

    Guanquan Liang

    2011-12-01

    Full Text Available A prototype of planar silicon photonic structure is designed and simulated to provide narrow resonant line-width (∼2 nm in a wide photonic band gap (∼210 nm with broad tunable resonant wavelength range (∼100 nm around the optical communication wavelength 1550 nm. This prototype is based on the combination of two modified basic photonic structures, i.e. a split tapered photonic crystal micro-cavity embedded in a photonic wire waveguide, and a slot waveguide with narrowed slabs. This prototype is then further integrated with a MEMS (microelectromechanical systems based electrostatic comb actuator to achieve “coarse tune” and “fine tune” at the same time for wide range and narrow-band filtering and modulating. It also provides a wide range tunability to achieve the designed resonance even fabrication imperfection occurs.