WorldWideScience

Sample records for sun transit sensor

  1. Micro technology based sun sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Pedersen, Martin; Fléron, René

    2003-01-01

    There is increasing interest among universities in the scientific and educational possibilities of picosatellites base on the CubeSat 5 concept. Due to sever mass and dimension constraints place on this type of satellites, new approaches and ideas regarding different systems arises to accommodate...... DTUsat sun sensors are needed along with a magnetometer to obtain unambiguous attitude determination for the ACDS and the payloads - an electrodynamic tether and a camera. The accuracy needed was not obtainable by employing conventional attitude sensors. Hence a linear slit sensor was designed...

  2. Dual Axis Light Sensor for Tracking Sun

    Science.gov (United States)

    Shibata, Miki; Tambo, Toyokazu

    We have developed convenient light sensors to control a platform of solar cell panel. Dual axis light sensor in the present paper has structure of 5 PD (photodiode) light sensor which is composed of 5 photodiodes attached on a frustum of pyramid(1). Light source can be captured in front of the sensor by rotating the X and Y axis as decreasing the output deviation between two pairs of outside photodiodes. We here report the mechanism of sun tacking using the dual axis 5 PD light sensor and the fundamental results performed in the dark room.

  3. Design and Fabrication of an Albedo Insensitive Analog Sun Sensor

    NARCIS (Netherlands)

    Wu, H.; Emadi, A.; De Graaf, G.; Leijtens, J.; Wolffenbuttel, R.F.

    2011-01-01

    A sun sensor is usually included in a satellite for optically measuring the position relative to the sun. The accuracy of a conventional sun sensor is affected by reflected sunlight at the nearby earth atmosphere: the albedo radiation. The part of the spectrum at near IR (1.5 μm) is not included in

  4. Multi-Aperture CMOS Sun Sensor for Microsatellite Attitude Determination

    Directory of Open Access Journals (Sweden)

    Michele Grassi

    2009-06-01

    Full Text Available This paper describes the high precision digital sun sensor under development at the University of Naples. The sensor determines the sun line orientation in the sensor frame from the measurement of the sun position on the focal plane. It exploits CMOS technology and an original optical head design with multiple apertures. This allows simultaneous multiple acquisitions of the sun as spots on the focal plane. The sensor can be operated either with a fixed or a variable number of sun spots, depending on the required field of view and sun-line measurement precision. Multiple acquisitions are averaged by using techniques which minimize the computational load to extract the sun line orientation with high precision. Accuracy and computational efficiency are also improved thanks to an original design of the calibration function relying on neural networks. Extensive test campaigns are carried out using a laboratory test facility reproducing sun spectrum, apparent size and distance, and variable illumination directions. Test results validate the sensor concept, confirming the precision improvement achievable with multiple apertures, and sensor operation with a variable number of sun spots. Specifically, the sensor provides accuracy and precision in the order of 1 arcmin and 1 arcsec, respectively.

  5. Spacecraft Attitude Determination with Earth Albedo Corrected Sun Sensor Measurements

    DEFF Research Database (Denmark)

    Bhanderi, Dan

    This thesis focuses on advanced modeling of the Earth albedo experienced by satellites in Earth orbit. The model of the Earth albedo maintains directional information of the Earth albedo irradiance from each partition on the Earth surface. This allows enhanced modeling of Sun sensor current outputs......-Method, Extended Kalman Filter, and Unscented Kalman Filter algorithms are presented and the results are compared. Combining the Unscented Kalman Filter with Earth albedo and enhanced Sun sensor modeling allows for three-axis attitude determination from Sun sensor only, which previously has been perceived...

  6. System modeling based measurement error analysis of digital sun sensors

    Institute of Scientific and Technical Information of China (English)

    WEI; M; insong; XING; Fei; WANG; Geng; YOU; Zheng

    2015-01-01

    Stringent attitude determination accuracy is required for the development of the advanced space technologies and thus the accuracy improvement of digital sun sensors is necessary.In this paper,we presented a proposal for measurement error analysis of a digital sun sensor.A system modeling including three different error sources was built and employed for system error analysis.Numerical simulations were also conducted to study the measurement error introduced by different sources of error.Based on our model and study,the system errors from different error sources are coupled and the system calibration should be elaborately designed to realize a digital sun sensor with extra-high accuracy.

  7. Low-Power Low-Noise CMOS Imager Design: in Micro-Digital Sun Sensor Application

    NARCIS (Netherlands)

    Xie, N.

    2012-01-01

    A digital sun sensor is superior to an analog sun sensor in aspects of resolution, albedo immunity, and integration. The proposed Micro-Digital Sun Sensor (µDSS) is an autonomous digital sun sensor which is implemented by means of a CMOS image sensor, which is named APS+. The µDSS is designed speci

  8. Micro-digital sun sensor: an imaging sensor for space applications

    NARCIS (Netherlands)

    Xie, N.; Theuwissen, A.J.P.; Büttgen, B.; Hakkesteegt, H.C.; Jasen, H.; Leijtens, J.A.P.

    2010-01-01

    Micro-Digital Sun Sensor is an attitude sensor which senses relative position of micro-satellites to the sun in space. It is composed of a solar cell power supply, a RF communication block and an imaging chip which is called APS+. The APS+ integrates a CMOS Active Pixel Sensor (APS) of 512×512 pixel

  9. Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations

    Science.gov (United States)

    O'Keefe, Stephen A.

    In recent years there has been a significant increase in interest in smaller satellites as lower cost alternatives to traditional satellites, particularly with the rise in popularity of the CubeSat. Due to stringent mass, size, and often budget constraints, these small satellites rely on making the most of inexpensive hardware components and sensors, such as coarse sun sensors (CSS) and magnetometers. More expensive high-accuracy sun sensors often combine multiple measurements, and use specialized electronics, to deterministically solve for the direction of the Sun. Alternatively, cosine-type CSS output a voltage relative to the input light and are attractive due to their very low cost, simplicity to manufacture, small size, and minimal power consumption. This research investigates using coarse sun sensors for performing robust attitude estimation in order to point a spacecraft at the Sun after deployment from a launch vehicle, or following a system fault. As an alternative to using a large number of sensors, this thesis explores sun-direction estimation techniques with low computational costs that function well with underdetermined sets of CSS. Single-point estimators are coupled with simultaneous nonlinear control to achieve sun-pointing within a small percentage of a single orbit despite the partially underdetermined nature of the sensor suite. Leveraging an extensive analysis of the sensor models involved, sequential filtering techniques are shown to be capable of estimating the sun-direction to within a few degrees, with no a priori attitude information and using only CSS, despite the significant noise and biases present in the system. Detailed numerical simulations are used to compare and contrast the performance of the five different estimation techniques, with and without rate gyro measurements, their sensitivity to rate gyro accuracy, and their computation time. One of the key concerns with reducing the number of CSS is sensor degradation and failure. In

  10. Micro digital sun sensor: system in a package

    NARCIS (Netherlands)

    Boom, C.W. de; Leijtens, J.A.P.; Duivenbode, L.M.H. van; Heiden, N. van der

    2004-01-01

    A novel micro Digital Sun Sensor (μDSS) is under development in the frame of a micro systems technology (MST) development program (Microned) from the Dutch Ministry of Economic Affairs. Use of available micro system technologies in combination with the implementation of a dedicated solarcell for pow

  11. Micro digital sun sensor: system in a package

    NARCIS (Netherlands)

    Boom, C.W. de; Leijtens, J.A.P.; Duivenbode, L.M.H. van; Heiden, N. van der

    2004-01-01

    A novel micro Digital Sun Sensor (μDSS) is under development in the frame of a micro systems technology (MST) development program (Microned) from the Dutch Ministry of Economic Affairs. Use of available micro system technologies in combination with the implementation of a dedicated solarcell for pow

  12. Micro digital sun sensor: system in a package

    NARCIS (Netherlands)

    Boom, C.W. de; Leijtens, J.A.P.; Duivenbode, L.M.H. van; Heiden, N. van der

    2004-01-01

    A novel micro Digital Sun Sensor (μDSS) is under development in the frame of a micro systems technology (MST) development program (Microned) from the Dutch Ministry of Economic Affairs. Use of available micro system technologies in combination with the implementation of a dedicated solarcell for

  13. What Is the Source of Quiet Sun Transition Region Emission?

    CERN Document Server

    Schmit, Donald

    2016-01-01

    Dating back to the first observations of the on-disk corona, there has been a qualitative link between the photosphere's magnetic network and enhanced transition-temperature plasma emission. These observations led to the development of a general model that describes emission structures through the partitioning of the atmospheric volume with different magnetic loop geometries that exhibit different energetic equilibria. Does the internetwork produce transition-temperature emission? What fraction of network flux connects to the corona? How does quiet sun emission compare with low-activity Sun-like stars? In this work, we revisit the canonical model of the quiet sun, with high-resolution observations from IRIS and HMI in hand, to address those questions. We use over 900 deep exposures of Si IV 1393A from IRIS along with nearly simultaneous HMI magnetograms to quantify the correlation between transition-temperature emission structures and magnetic field concentrations through a number of novel statistics. Our obs...

  14. An autonomous low power high resolution micro-digital sun sensor

    NARCIS (Netherlands)

    Xie, N.; Theuwissen, A.J.P.

    2011-01-01

    Micro-Digital Sun Sensor (μDSS) is a sun detector which senses the respective angle between a satellite and the sun. It is composed of a solar cell power supply, a RF communication block and a CMOS Image Sensor (CIS) chip, which is called APS+. The paper describes the implementation of a prototype o

  15. An autonomous low power high resolution micro-digital sun sensor

    NARCIS (Netherlands)

    Xie, N.; Theuwissen, A.J.P.

    2011-01-01

    Micro-Digital Sun Sensor (μDSS) is a sun detector which senses the respective angle between a satellite and the sun. It is composed of a solar cell power supply, a RF communication block and a CMOS Image Sensor (CIS) chip, which is called APS+. The paper describes the implementation of a prototype

  16. Low-power high-accuracy micro-digital sun sensor by means of a CMOS image sensor

    NARCIS (Netherlands)

    Xie, N.; Theuwissen, A.J.P.

    2013-01-01

    A micro-digital sun sensor (μDSS) is a sun detector which senses a satellite’s instant attitude angle with respect to the sun. The core of this sensor is a system-on-chip imaging chip which is referred to as APS+. The APS+ integrates a CMOS active pixel sensor (APS) array of 368×368  pixels , a 12-b

  17. A low-power and high-precision miniaturized digital sun sensor

    NARCIS (Netherlands)

    Boer, B.M. de; Durkut, M.

    2013-01-01

    A prototype miniaturized digital sun sensor (miniDSS) was developed by TNO. It is expected to be launched on QuadSat for in-orbit demonstration. The single-chip sun sensor comprises an application specific integrated circuit (ASIC) on which an active pixel sensor (APS), read-out and processing circu

  18. What Is the Source of Quiet Sun Transition Region Emission?

    Science.gov (United States)

    Schmit, D. J.; De Pontieu, Bart

    2016-11-01

    Dating back to the first observations of the on-disk corona, there has been a qualitative link between the photosphere’s magnetic network and enhanced transition-temperature plasma emission. These observations led to the development of a general model that describes emission structures through the partitioning of the atmospheric volume with different magnetic loop geometries that exhibit different energetic equilibria. Does the internetwork produce transition-temperature emission? What fraction of network flux connects to the corona? How does quiet Sun emission compare with low-activity Sun-like stars? In this work, we revisit the canonical model of the quiet Sun, with high-resolution observations from the Interface Region Imaging Spectrograph (IRIS) and HMI in hand, to address those questions. We use over 900 deep exposures of Si iv 1393 Å from IRIS along with nearly simultaneous HMI magnetograms to quantify the correlation between transition-temperature emission structures and magnetic field concentrations through a number of novel statistics. Our observational results are coupled with analysis of the Bifrost MHD model and a large-scale potential field model. Our results paint a complex portrait of the quiet Sun. We measure an emission signature in the distant internetwork that cannot be attributed to network contribution. We find that the dimmest regions of emission are not linked to the local vertical magnetic field. Using the MHD simulation, we categorize the emission contribution from cool mid-altitude loops and high-altitude coronal loops and discuss the potential emission contribution of spicules. Our results provide new constraints on the coupled solar atmosphere so that we can build on our understanding of how dynamic thermal and magnetic structures generate the observed phenomena in the transition region.

  19. Detection of Planetary Transits Across a Sun-like Star

    CERN Document Server

    Charbonneau, D; Latham, D W; Mayor, M; Charbonneau, David; Brown, Timothy M.; Latham, David W.; Mayor, Michel

    1999-01-01

    We report high precision, high cadence photometric measurements of the star HD 209458, which is known from radial velocity measurements to have a planetary mass companion in a close orbit. We detect two separate transit events at times that are consistent with the radial velocity measurements. In both cases, the detailed shape of the transit curve due to both the limb darkening of the star and the finite size of the planet is clearly evident. Assuming stellar parameters of 1.1 R_Sun and 1.1 M_Sun, we find that the data are best interpreted as a gas giant with a radius of 1.27 +/- 0.02 R_Jup in an orbit with an inclination of 87.1 +/- 0.2 degrees. We present values for the planetary surface gravity, escape velocity, and average density, and discuss the numerous observations that are warranted now that a planet is known to transit the disk of its parent star.

  20. Modeling Earth Albedo Currents on Sun Sensors for Improved Vector Observations

    DEFF Research Database (Denmark)

    Bhanderi, Dan

    2006-01-01

    Earth albedo influences vector measurements of the solar line of sight vector, due to the induced current on in the photo voltaics of Sun sensors. Although advanced digital Sun sensors exist, these are typically expensive and may not be suited for satellites in the nano or pico-class. Previously...... for modeling Sun sensor output by incorporating the Earth albedo model is presented. This model utilizes the directional information of in the Earth albedo model, which is achieved by Earth surface partitioning. This allows accurate simulation of the Sun sensor output and the results are consistent with Ørsted...... and useful for space environment simulations, and may be utilized to improve attitude estimation algorithms applying Sun sensor vector observations....

  1. Investigation of Digital Sun Sensor Technology with an N-Shaped Slit Mask

    Directory of Open Access Journals (Sweden)

    Zheng You

    2011-10-01

    Full Text Available Nowadays sun sensors are being more widely used in satellites to determine the sunray orientation, thus development of a new version of sun sensor with lighter mass, lower power consumption and smaller size it of considerable interest. This paper introduces such a novel digital sun sensor, which is composed of a micro-electro-mechanical system (MEMS mask with an N-shaped slit as well as a single linear array charge-coupled device (CCD. The sun sensor can achieve the measurement of two-axis sunray angles according to the three sun spot images on the CCD formed by sun light illumination through the mask. Given the CCD glass layer, an iterative algorithm is established to correct the refraction error. Thus, system resolution, update rate and other characteristics are improved based on the model simulation and system design. The test of sun sensor prototype is carried out on a three-axis rotating platform with a sun simulator. The test results show that the field of view (FOV is ±60° × ±60° and the accuracy is 0.08 degrees of arc (3σ in the whole FOV. Since the power consumption of the prototype is only 300 mW and the update rate is 14 Hz, the novel digital sun sensor can be applied broadly in micro/nano-satellites, even pico-satellites.

  2. SunLine Transit Agency Fuel Cell Transit Bus: Fifth Evaluation Report (Report and Appendices)

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2009-08-01

    This report describes operations at SunLine Transit Agency for a prototype fuel cell bus and five compressed natural gas (CNG) buses. This is the fifth evaluation report for this site, and it describes results and experiences from October 2008 through June 2009. These results are an addition to those provided in the previous four evaluation reports.

  3. SunLine Transit Agency Fuel Cell Transit Bus: Fourth Evaluation Report (Report and Appendices)

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, K.; Eudy, L.

    2009-01-01

    This report describes operations at SunLine Transit Agency for a prototype fuel cell bus and five new compressed natural gas (CNG) buses. This is the fourth evaluation report for this site, and it describes results and experiences from April 2008 through October 2008. These results are an addition to those provided in the previous three evaluation reports.

  4. TRANSITING THE SUN. II. THE IMPACT OF STELLAR ACTIVITY ON Lyα TRANSITS

    Energy Technology Data Exchange (ETDEWEB)

    Llama, J.; Shkolnik, E. L., E-mail: joe.llama@lowell.edu [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2016-01-20

    High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure the properties of transiting exoplanets in the presence of stellar activity. Here we insert the transit of a hot Jupiter into continuous disk integrated data of the Sun in Lyα from NASA’s Solar Dynamics Observatory/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio (R{sub p}/R{sub ⋆}). In 75% of our simulated light curves, we measure the correct radius ratio; however, incorrect values can be measured if there is significant short-term variability in the light curve. The maximum measured value of R{sub p}/R{sub ⋆} is 50% larger than the input value, which is much smaller than the large Lyα transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations without a transit and found that stellar activity cannot mimic the Lyα transit of 55 Cancari b, strengthening the conclusion that this planet has a partially transiting exopshere. We were able to compare our simulations to more active stars by artificially increasing the variability in the Solar Lyα light curve. In the higher variability data, the largest value of R{sub p}/R{sub ⋆} we measured is <3× the input value, which again is not large enough to reproduce the Lyα transit depth reported for the more active stars HD 189733 and GJ 436, supporting the interpretation that these planets have extended atmospheres and possible cometary tails.

  5. Transiting the Sun II: The impact of stellar activity on Lyman-$\\alpha$ transits

    CERN Document Server

    Llama, J

    2015-01-01

    High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure properties of transiting exoplanets in the presence of stellar activity. Here we insert transits of a hot Jupiter into continuous disk integrated data of the Sun in Lyman-alpha (Ly$\\alpha$) from NASA's SDO/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio $(\\textrm{R}_\\textrm{p}/\\textrm{R}_\\star)$. In 75% of our simulated light curves we measure the correct radius ratio; however, incorrect values can be measured if there is significant short term variability in the light curve. The maximum measured value of $(\\textrm{R}_\\textrm{p}/\\textrm{R}_\\star)$ is $50\\%$ larger than the input value, which is much smaller than the large Ly$\\alpha$ transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations withou...

  6. A Circular aperture-array structure optical system for digital sun sensor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the first type of Rayleigh Sommerfeld diffraction formula, an imaging model of circular aperture-array structure digital sun sensor optical system is developed. Then a 6×6 circular aperture-array structure optical system is designed. The results of numerical simulation show that the optical system is designed well and is conformed to the requirements of miniaturization and high accuracy of sun sensor.

  7. Sun

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Sun Microsystems, Inc. is committed to open standards,a standardization system, and sharing within the information tech nology field, focusing not only on technical innovation, but also on new ideas, practices and future development.

  8. Transiting the Sun: The impact of stellar activity on X-ray and ultraviolet transits

    CERN Document Server

    Llama, J

    2015-01-01

    Transits of hot Jupiters in X-rays and the ultraviolet have been shown to be both deeper and more variable than the corresponding optical transits. This variability has been attributed to hot Jupiters having extended atmospheres at these wavelengths. Using resolved images of the Sun from NASA's Solar Dynamics Observatory spanning 3.5 years of Solar Cycle 24 we simulate transit light curves of a hot Jupiter to investigate the impact of Solar like activity on our ability to reliably recover properties of the planet's atmosphere in soft X-rays (94 {\\AA}), the UV (131-1700 {\\AA}), and the optical (4500 {\\AA}). We find that for stars with similar activity levels to the Sun, the impact of stellar activity results in the derived radius of the planet in soft X-ray/EUV to be underestimated by up-to 25% or overestimated by up-to 50% depending on whether the planet occults active regions. We also find that in up-to 70% of the X-ray light curves the planet transits over bright star spots. In the far ultraviolet (1600 &am...

  9. A highly accurate wireless digital sun sensor based on profile detecting and detector multiplexing technologies

    Science.gov (United States)

    Wei, Minsong; Xing, Fei; You, Zheng

    2017-01-01

    The advancing growth of micro- and nano-satellites requires miniaturized sun sensors which could be conveniently applied in the attitude determination subsystem. In this work, a profile detecting technology based high accurate wireless digital sun sensor was proposed, which could transform a two-dimensional image into two-linear profile output so that it can realize a high update rate under a very low power consumption. A multiple spots recovery approach with an asymmetric mask pattern design principle was introduced to fit the multiplexing image detector method for accuracy improvement of the sun sensor within a large Field of View (FOV). A FOV determination principle based on the concept of FOV region was also proposed to facilitate both sub-FOV analysis and the whole FOV determination. A RF MCU, together with solar cells, was utilized to achieve the wireless and self-powered functionality. The prototype of the sun sensor is approximately 10 times lower in size and weight compared with the conventional digital sun sensor (DSS). Test results indicated that the accuracy of the prototype was 0.01° within a cone FOV of 100°. Such an autonomous DSS could be equipped flexibly on a micro- or nano-satellite, especially for highly accurate remote sensing applications.

  10. Design and realization of the miniature long-life integrative coded sun sensor

    Science.gov (United States)

    Mo, Yanan; Cui, Jian; Zhao, Yuan; Chen, Ran; Liu, Xin

    2013-10-01

    This paper describes the research activity at the Beijing institute of control engineering about the miniature long-life integrative coded sun sensor. The light system of the miniature coded sun sensor is composed with a semi-column silex glass, a cube silex with coded shape on the bottom and an integrative silicon battery with 14 cells. The sun line forms a light spot through the slit on light system on the coded plate. The sensor determines the orientation of sun through the position of light spot. With the limitation of the diameter of sun plate the accuracy of only 0.5° can be realized with 8-bit coarse code in FOV of 124°. To achieve high accuracy of 0.05° the subdivision technique must be adopted. The main scheme of the miniature long-life integrative coded sun sensor is integrating the light system and the signal processing circuits in one mechanical house, using FPGA to calculate the angle, generate the control signal of Multiplexer and AD and realize the function of UART, using flexibility board to connect analog board and digital board, using second power of the satellite, using RS422 interface to communicate with central computer. The performance of the miniature long-life integrative coded sun sensor is listed as below : FOV 124°x124°,accuracy 0.05°(3σ), resolution 14″, power consumption 0.5W,update rate 40Hz,mass 475g, designed life-time 15 years. It has been adopted in the new platform of Remote Sensing Satellite of CAST. The first flight will be at 2015.

  11. A microfabricated sun sensor using GaN-on-sapphire ultraviolet photodetector arrays

    Science.gov (United States)

    Miller, Ruth A.; So, Hongyun; Chiamori, Heather C.; Suria, Ateeq J.; Chapin, Caitlin A.; Senesky, Debbie G.

    2016-09-01

    A miniature sensor for detecting the orientation of incident ultraviolet light was microfabricated using gallium nitride (GaN)-on-sapphire substrates and semi-transparent interdigitated gold electrodes for sun sensing applications. The individual metal-semiconductor-metal photodetector elements were shown to have a stable and repeatable response with a high sensitivity (photocurrent-to-dark current ratio (PDCR) = 2.4 at -1 V bias) and a high responsivity (3200 A/W at -1 V bias) under ultraviolet (365 nm) illumination. The 3 × 3 GaN-on-sapphire ultraviolet photodetector array was integrated with a gold aperture to realize a miniature sun sensor (1.35 mm × 1.35 mm) capable of determining incident light angles with a ±45° field of view. Using a simple comparative figure of merit algorithm, measurement of incident light angles of 0° and 45° was quantitatively and qualitatively (visually) demonstrated by the sun sensor, supporting the use of GaN-based sun sensors for orientation, navigation, and tracking of the sun within the harsh environment of space.

  12. Modeling Earth Albedo Currents on Sun Sensors for Improved Vector Observations

    DEFF Research Database (Denmark)

    Bhanderi, Dan

    2006-01-01

    Earth albedo influences vector measurements of the solar line of sight vector, due to the induced current on in the photo voltaics of Sun sensors. Although advanced digital Sun sensors exist, these are typically expensive and may not be suited for satellites in the nano or pico-class. Previously...... data, showing significant improvement in the Earth albedo induced current estimates. Additionally an algorithm for utilizing the Earth albedo model in obtaining a vector observation pair which is superior to the solar line of sight vector pair. It is concluded that the Earth albedo model is valid...

  13. Accurate and Wide-Field-of-View MEMS-Based Sun Sensor for Industrial Applications

    OpenAIRE

    Delgado Seseña, Francisco José; Quero Reboul, José Manuel; García Ortega, Juan de la Cruz; López Tarrida, Cristina; Ortega, Pablo R; Bermejo, Sandra

    2012-01-01

    This paper describes the design, fabrication, sim- ulation, and experimental results of an improved miniaturized two-axis sun sensor for industrial applications, created by adapt- ing a technology used previously in satellite applications. The sensor for each axis is composed of six photodiodes integrated in a crystalline-silicon substrate and a layer of cover glass, which is used to protect the silicon and to hold the windows. The high preci...

  14. Superconducting Metallic Glass Transition-Edge-Sensors

    Science.gov (United States)

    Hays, Charles C. (Inventor)

    2013-01-01

    A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

  15. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Fourth Results Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2013-01-01

    SunLine Transit Agency, which provides public transit services to the Coachella Valley area of California, has demonstrated hydrogen and fuel cell bus technologies for more than 10 years. In May 2010, SunLine began demonstrating the advanced technology (AT) fuel cell bus with a hybrid electric propulsion system, fuel cell power system, and lithium-based hybrid batteries. This report describes operations at SunLine for the AT fuel cell bus and five compressed natural gas buses. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is working with SunLine to evaluate the bus in real-world service to document the results and help determine the progress toward technology readiness. NREL has previously published three reports documenting the operation of the fuel cell bus in service. This report provides a summary of the results with a focus on the bus operation from February 2012 through November 2012.

  16. Large Format Transition Edge Sensor Microcalorimeter Arrays

    Science.gov (United States)

    Chervenak, J. A.; Adams, J. A.; Bandler, S. b.; Busch, S. E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, J. P.; Porter, F. S.; Ray, C.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.

    2012-01-01

    We have produced a variety of superconducting transition edge sensor array designs for microcalorimetric detection of x-rays. Designs include kilopixel scale arrays of relatively small sensors (approximately 75 micron pitch) atop a thick metal heat sinking layer as well as arrays of membrane-isolated devices on 250 micron and up to 600 micron pitch. We discuss fabrication and performance of microstripline wiring at the small scales achieved to date. We also address fabrication issues with reduction of absorber contact area in small devices.

  17. A Novel Multi-Aperture Based Sun Sensor Based on a Fast Multi-Point MEANSHIFT (FMMS Algorithm

    Directory of Open Access Journals (Sweden)

    Gao-Fei Zhang

    2011-03-01

    Full Text Available With the current increased widespread interest in the development and applications of micro/nanosatellites, it was found that we needed to design a small high accuracy satellite attitude determination system, because the star trackers widely used in large satellites are large and heavy, and therefore not suitable for installation on micro/nanosatellites. A Sun sensor + magnetometer is proven to be a better alternative, but the conventional sun sensor has low accuracy, and cannot meet the requirements of the attitude determination systems of micro/nanosatellites, so the development of a small high accuracy sun sensor with high reliability is very significant. This paper presents a multi-aperture based sun sensor, which is composed of a micro-electro-mechanical system (MEMS mask with 36 apertures and an active pixels sensor (APS CMOS placed below the mask at a certain distance. A novel fast multi-point MEANSHIFT (FMMS algorithm is proposed to improve the accuracy and reliability, the two key performance features, of an APS sun sensor. When the sunlight illuminates the sensor, a sun spot array image is formed on the APS detector. Then the sun angles can be derived by analyzing the aperture image location on the detector via the FMMS algorithm. With this system, the centroid accuracy of the sun image can reach 0.01 pixels, without increasing the weight and power consumption, even when some missing apertures and bad pixels appear on the detector due to aging of the devices and operation in a harsh space environment, while the pointing accuracy of the single-aperture sun sensor using the conventional correlation algorithm is only 0.05 pixels.

  18. Cassini Ring Plane Crossings: Hypervelocity Impact Risks to Sun Sensor Assemblies

    Science.gov (United States)

    Lee, Allan Y.

    2016-01-01

    For both F/G and D-ring crossings: Probability of a penetration damage of the SSH (Sun Sensor Head) window glass is very low; Optical attenuation due to craters on the surface of the window glass caused by direct HVI (Hyper-Velocity Impact) by dust particle is estimated to be less than 1 percent; Optical attenuation due to secondary debris cloud generated by the disintegrated ring dust particles is estimated to be less than 1 percent. To better manage the Sun sensor damage risk during selected proximal orbit crossings, it is highly desirable to follow the contingency procedures mentioned in Section VII of the paper: Details of this contingency procedure are given in the paper entitled "Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings" authored by David M. Bates. Based on results of risk analyses documented in this work and contingency planning work described in the paper mentioned above, we judge that the proximal orbit campaign will be safe from the viewpoint of dust HVI hazard.

  19. Using the 2016 Transit of Mercury to Find the Distance to the Sun

    Science.gov (United States)

    Pasachoff, Jay M.; Gährken, Bernd; Schneider, Glenn

    2017-01-01

    In this article, the authors describe their use of simultaneous observations of the 2016 transit of Mercury made from two widely separated locations on Earth to determine the distance to the Sun in a way different from that suggested in 1715 by Halley. Using an internet link, teachers and students can make a similar derivation at the 2019 transit…

  20. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: First Results Report

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2011-03-01

    This report describes operations at SunLine Transit Agency for their newest prototype fuel cell bus and five compressed natural gas (CNG) buses. In May 2010, SunLine began operating its sixth-generation hydrogen fueled bus, an Advanced Technology (AT) fuel cell bus that incorporates the latest design improvements to reduce weight and increase reliability and performance. The agency is collaborating with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to evaluate the bus in revenue service. This report provides the early data results and implementation experience of the AT fuel cell bus since it was placed in service.

  1. Pico-satellite Autonomous Navigation with Magnetometer and Sun Sensor Data

    Institute of Scientific and Technical Information of China (English)

    HAN Ke; WANG Hao; TU Binjie; JIN Zhonghe

    2011-01-01

    This article presents a near-Earth satellite orbit estimation method for pico-satellite applications with light-weight and low-power requirements.The method provides orbit information autonomously from magnetometer and sun sensor, with an extended Kalman filter (EKF).Real-time position/velocity parameters are estimated with attitude independently from two quantities: the measured magnitude of the Earth's magnetic field, and the measured dot product of the magnetic field vector and the sun vector.To guarantee the filter's effectiveness, it is recommended that the sun sensor should at least have the same level of accuracy as magnetometer.Furthermore, to reduce filter's computation expense, simplification methods in EKF's Jacobian calculations are introduced and testified, and a polynomial model for fast magnetic field calculation is developed.With these methods,50% of the computation expense in dynamic model propagation and 80% of the computation burden in measurement model calculation can be reduced.Tested with simulation data and compared with original magnetometer-only methods, filter achieves faster convergence and higher accuracy by 75% and 30% respectively, and the suggested simplification methods are proved to be harmless to filter's estimation performance.

  2. Application of the Langley plot for calibration of sun sensors for the Halogen Occultation Experiment (HALOE)

    Science.gov (United States)

    Moore, Alvah S., Jr.; Mauldin, L. ED, III; Stump, Charles W.; Reagan, John A.; Fabert, Milton G.

    1989-01-01

    The calibration of the Halogen Occultation Experiment (HALOE) sun sensor is described. This system consists of two energy-balancing silicon detectors which provide coarse azimuth and elevation control signals and a silicon photodiode array which provides top and bottom solar edge data for fine elevation control. All three detectors were calibrated on a mountaintop near Tucson, Ariz., using the Langley plot technique. The conventional Langley plot technique was modified to allow calibration of the two coarse detectors, which operate wideband. A brief description of the test setup is given. The HALOE instrument is a gas correlation radiometer that is now being developed for the Upper Atmospheric Research Satellite.

  3. Using the 2016 Transit of Mercury to Find the Distance to the Sun

    Science.gov (United States)

    Pasachoff, Jay M.; Gährken, Bernd; Schneider, Glenn

    2017-03-01

    The May 9, 2016, transit of Mercury was observed simultaneously from the Big Bear Solar Observatory in California and from a site in Germany. From the measured displacement between the views from the two sites of Mercury's disk silhouetted against the solar granulation, we were able to calculate the distance to the Sun in linear units (kilometers), not merely the proportionality given by Kepler's third law.

  4. Ubiquitous High Speed Transition Region and Coronal Upflows in the Quiet Sun

    CERN Document Server

    Mcintosh, Scott W

    2009-01-01

    We study the line profiles of a range of transition region (TR) emission lines observed in typical quiet Sun regions. In magnetic network regions, the Si IV 1402\\AA{}, C IV 1548\\AA{}, N V 1238\\AA{}, O VI 1031\\AA{}, and Ne VIII 770\\AA{} spectral lines show significant asymmetry in the blue wing of the emission line profiles. We interpret these high-velocity upflows in the lower and upper TR as the quiet Sun equivalent of the recently discovered upflows in the low corona above plage regions (Hara et al., 2008). The latter have been shown to be directly associated with high-velocity chromospheric spicules that are (partially) heated to coronal temperatures and play a significant role in supplying the active region corona with hot plasma (DePontieu et al., 2009}. We show that a similar process likely dominates the quiet Sun network. We provide a new interpretation of the observed quiet Sun TR emission in terms of the relentless mass transport between the chromosphere and corona - a mixture of emission from dynami...

  5. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Third Results Reports

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2012-05-01

    This report describes operations at SunLine Transit Agency for their newest prototype fuel cell bus and five compressed natural gas (CNG) buses. In May 2010, SunLine began operating its sixth-generation hydrogen fueled bus, an Advanced Technology (AT) fuel cell bus that incorporates the latest design improvements to reduce weight and increase reliability and performance. The agency is collaborating with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to evaluate the bus in revenue service. NREL has previously published two reports documenting the operation of the fuel cell bus in service. This report provides a summary of the results with a focus on the bus operation from July 2011 through January 2012.

  6. SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Second Results Report and Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Eudy, L.; Chandler, K.

    2011-10-01

    This report describes operations at SunLine Transit Agency for their newest prototype fuel cell bus and five compressed natural gas (CNG) buses. In May 2010, SunLine began operating its sixth-generation hydrogen fueled bus, an Advanced Technology (AT) fuel cell bus that incorporates the latest design improvements to reduce weight and increase reliability and performance. The agency is collaborating with the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to evaluate the bus in revenue service. This is the second results report for the AT fuel cell bus since it was placed in service, and it focuses on the newest data analysis and lessons learned since the previous report. The appendices, referenced in the main report, provide the full background for the evaluation. They will be updated as new information is collected but will contain the original background material from the first report.

  7. Comparing High-speed Transition Region Jets in Coronal Holes and Quiet Sun Regions

    Science.gov (United States)

    Tate Arbacher, Rebecca; Tian, Hui; Cranmer, Steven R.

    2015-01-01

    The complicated energy transfer and plasma motion in the transition region, between the photosphere and the corona, may play a significant role in the formation and acceleration of the solar wind. New observations from the Interface Region Imaging Spectrograph (IRIS) have revealed unprecedented levels of detail in this less-studied region. Coronal holes in particular are a likely source of solar wind material, though the formation and acceleration mechanisms of the fast solar wind are still largely unknown. In our previous work, we have reported the prevalence of small-scale high-speed (~80-250 km/s) jets with transition region temperatures from the network structures of coronal holes. Here we undertake a comparative study of these short-lived episodic network jets in a coronal hole region and a quiet sun region using IRIS sit-and-stare slit-jaw imaging in the 1330 Angstrom (C II) passband. The pointing coordinates, exposure time, observing cadence, and field of view of both observations are all identical. Our preliminary study suggests that the speeds and lengths of the network jets may differ between quiet sun and coronal hole regions. The quiet sun region exhibits many compact bright regions with sizes of 5-10 arcseconds which produce very few jets. The jets that do exist tend to propagate at much slower speeds over smaller distances than their coronal hole counterparts. Comparatively, in the coronal hole, such compact regions are almost absent and all network patches are permeated by the intermittent high-reaching jets. Such a difference suggests that magnetic loops are much smaller in the coronal hole and the network jets are produced at low heights. The recurrence frequency seems to be higher in the coronal hole region, with many of the isolated quiet sun region jets demonstrating curved trajectories.This work is supported under contract 8100002705 from Lockheed-Martin to SAO and by the NSF-REU solar physics program at SAO, grant number AGS-1263241.

  8. On-orbit Demonstration of a Sun Sensor on the Micro-Satellite MAIDO-1

    Directory of Open Access Journals (Sweden)

    Hiroshi Okubo

    2011-12-01

    Full Text Available 0 0 1 219 1249 International Islamic University 10 2 1466 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman";} A 50-kg-class microsatellite “MAIDO-1 (SOHLA-1” was launched, along with six other piggyback subsatellites, by a Japanese H-2A rocket on January 23, 2009. The fundamental and detailed designs of the satellite were developed by university students under the technical guidance of the Japan Aerospace Exploration Agency (JAXA. A string-type sun sensor (Fudai Sun Sensor; FSS was also developed by the students with the technical assistance of JAXA and Advanced Engineering Services (AES Co. Ltd. The FSS was mounted on the satellite as an experimental component. This paper reports the development of MAIDO-1 and FSS as well as the satellite operation by the students and the results of on-orbit experiments. ABSTRAK: Satu mikrosatelit kelas 50 kg “MAIDO-1 (SOHLA-1” telah dilancarkan, bersama enam lagi subsatelit gendong, dengan menggunakan roket H-2A (Jepun pada 23 Januari, 2009. Reka bentuk satelit yang asas dan terperinci dibangunkan oleh para pelajar universiti di bawah bimbingan teknikal Agensi Explorasi Aeroangkasa Jepun (Japan Aerospace Exploration Agency (JAXA. Sejenis penderia matahari bertali (Fudai Sun Sensor; FSS juga dibangunkan oleh para penuntut dengan bantuan teknikal dari pihak JAXA dan Advanced Engineering Services (AES Sdn. Bhd. FSS telah dilekapkan ke satelit sebagai komponen eksperimental. Kertas ini membentangkan perkembangan MAIDO-1 dan FSS, operasi satelit oleh pelajar-pelajar dan keputusan eksperimen semasa dalam orbit.

  9. Signal Conditioning for the Kalman Filter: Application to Satellite Attitude Estimation with Magnetometer and Sun Sensors.

    Science.gov (United States)

    Esteban, Segundo; Girón-Sierra, Jose M; Polo, Óscar R; Angulo, Manuel

    2016-10-31

    Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework.

  10. Signal Conditioning for the Kalman Filter: Application to Satellite Attitude Estimation with Magnetometer and Sun Sensors

    Directory of Open Access Journals (Sweden)

    Segundo Esteban

    2016-10-01

    Full Text Available Most satellites use an on-board attitude estimation system, based on available sensors. In the case of low-cost satellites, which are of increasing interest, it is usual to use magnetometers and Sun sensors. A Kalman filter is commonly recommended for the estimation, to simultaneously exploit the information from sensors and from a mathematical model of the satellite motion. It would be also convenient to adhere to a quaternion representation. This article focuses on some problems linked to this context. The state of the system should be represented in observable form. Singularities due to alignment of measured vectors cause estimation problems. Accommodation of the Kalman filter originates convergence difficulties. The article includes a new proposal that solves these problems, not needing changes in the Kalman filter algorithm. In addition, the article includes assessment of different errors, initialization values for the Kalman filter; and considers the influence of the magnetic dipole moment perturbation, showing how to handle it as part of the Kalman filter framework.

  11. Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings

    Science.gov (United States)

    Bates, David M.

    2016-01-01

    NASA's Cassini Spacecraft, launched on October 15th, 1997 which arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004–08), and has since been approved for a first and second extended mission through 2017. As part of the final extended missions, Cassini will begin an aggressive and exciting campaign of high inclination, low altitude flybys within the inner most rings of Saturn, skimming Saturn’s outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, requires a strategy for managing the Sun Sensor Assembly (SSA) health, the details of which are presented in this paper.

  12. Evaluation of radiation interference in the Voyager Sun Sensor's cadmium sulfide detector

    Science.gov (United States)

    Clarke, T. C.; Divita, E. L.

    1978-01-01

    The simulation of radiation interference effects and the results of a radiation interference test on two Voyager Sun Sensor prototype detector assemblies are reported. The derivation of test levels and requirements are discussed and show that cobalt 60 gamma radiation is an effective and practical simulator of the ionization dose rate effects induced by high-energy electron flux incident on the spacecraft at a rate of 3.7 x 10 to the 8th e/sq cm-sec (10 rad(Si)/s) during closest approach to Jupiter. The test results provide information that is used to confirm an analytic correlation, and to predict satisfactory performance of a spacecraft sun sensing device having stringent angular resolution requirements. The measured detector response shows that at dose rates incident on the detector elements of 2 rad(Si)/sec, which is four times that expected during Jupiter encounter, the radiation-induced angle error is almost an order of magnitude less than that allowed by the acceptance criteria.

  13. Position-sensitive transition-edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Iyomoto, N. [NASA/GSFC, Greenbelt, MD 20771 (United States)]. E-mail: iyomoto@milkyway.gsfc.nasa.gov; Bandler, S.R. [NASA/GSFC, Greenbelt, MD 20771 (United States); Brekosky, R.P. [NASA/GSFC, Greenbelt, MD 20771 (United States); Chervenak, J.A. [NASA/GSFC, Greenbelt, MD 20771 (United States); Figueroa-Feliciano, E. [NASA/GSFC, Greenbelt, MD 20771 (United States); Finkbeiner, F.M. [NASA/GSFC, Greenbelt, MD 20771 (United States); Kelley, R.L. [NASA/GSFC, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA/GSFC, Greenbelt, MD 20771 (United States); Lindeman, M.A. [University of Wisconsin, 1150 University Ave, Madison, WI 53706 (United States); Murphy, K. [NASA/GSFC, Greenbelt, MD 20771 (United States); Porter, F.S. [NASA/GSFC, Greenbelt, MD 20771 (United States); Saab, T. [NASA/GSFC, Greenbelt, MD 20771 (United States); Sadleir, J.E. [NASA/GSFC, Greenbelt, MD 20771 (United States); Talley, D.J. [NASA/GSFC, Greenbelt, MD 20771 (United States)

    2006-04-15

    We report the latest results from our development of Position-Sensitive Transition-edge sensors (PoSTs), which are one-dimensional imaging spectrometers. In PoSTs with segmented Au absorbers, we obtained 8eV energy resolution on K K{alpha} lines, which is consistent to the baseline energy resolution and the design values, on all of the nine pixels, by choosing the best combination of the thermal conductance in absorbers and in links that connects the absorbers. The pulse decay time of 193{mu}s is fast enough for our purpose. In a PoST with a continuous Bi/Cu absorber, by dividing the events into 63 effective pixels, we obtained energy resolutions of 16eV at the center 'pixel', which is comparable to the baseline energy resolution, and 33eV at the outer 'pixel'. The degradation of the energy resolution in the outer 'pixel' is due to position dependence, which we can cancel out by dividing the events into smaller 'pixels' when we have sufficient X-ray events.

  14. Modeling the impact of spectral sensor configurations on the FLD retrieval accuracy of sun-induced chlorophyll fluorescence

    NARCIS (Netherlands)

    Damm, A.; Erler, A.; Hillen, W.; Meroni, M.; Schaepman, M.E.; Verhoef, W.; Rascher, U.

    2011-01-01

    Chlorophyll fluorescence is related to photosynthesis and can serve as a remote sensing proxy for estimating photosynthetic energy conversion and carbon uptake. Recent advances in sensor technology allow remote measurements of the sun-induced chlorophyll fluorescence signal (Fs) at leaf and canopy s

  15. HAT-P-55b: A Hot Jupiter Transiting a Sun-like Star

    CERN Document Server

    Juncher, D; Hartman, J D; Bakos, G Á; Bieryla, A; Kovács, T; Boisse, I; Latham, D W; Kovács, G; Bhatti, W; Csubry, Z; Penev, K; de Val-Borro, M; Falco, E; Torres, G; Noyes, R W; Lázár, J; Papp, I; Sári, P

    2015-01-01

    We report the discovery of a new transiting extrasolar planet, HAT-P-55b. The planet orbits a V = 13.207 +/- 0.039 sun-like star with a mass of 1.013 +/- 0.037 solar masses, a radius of 1.011 +/- 0.036 solar radii and a metallicity of -0.03 +/- 0.08. The planet itself is a typical hot Jupiter with a period of 3.5852467 +/- 0.0000064 days, a mass of 0.582 +/- 0.056 Jupiter masses and a radius of 1.182 +/- 0.055 Jupiter radii. This discovery adds to the increasing sample of transiting planets with measured bulk densities, which is needed to put constraints on models of planetary structure and formation theories.

  16. Versatile Sensor for Transition, Separation, and Shock Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a simple, robust, sensor array for the detection of laminar/turbulent transition location, areas of flowfield separation, and shock wave...

  17. Asteroseismology of the Transiting Exoplanet Host HD 17156 with Hubble Space Telescope Fine Guidance Sensor

    DEFF Research Database (Denmark)

    Gilliland, Ronald L.; McCullough, Peter R.; Nelan, Edmund P.

    2011-01-01

    Observations conducted with the Fine Guidance Sensor on the Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in 2008 December on the host star of the transiting exoplanet HD 17156b. During this time, 1.0 × 1012 photons...... light curve. Using the density constraint from asteroseismology, and stellar evolution modeling results in M * = 1.285 ± 0.026 M sun, R * = 1.507 ± 0.012 R sun, and a stellar age of 3.2 ± 0.3 Gyr. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science...

  18. Assessment of MODIS sun-sensor geometry variations effect on observed NDVI using MSG SEVIRI geostationary data

    DEFF Research Database (Denmark)

    Fensholt, R.; Sandholt, I.; Proud, Simon Richard

    2010-01-01

    -sensor geometry variations will have a more visible impact on the Normalized Difference Vegetation Index (NDVI) from MODIS compared to earlier data sources, since noise related to atmosphere and sensor calibration is substantially reduced in the MODIS data stream. For this reason, the effect of varying MODIS...... viewing geometry on red, near-infrared (NIR) and NDVI needs to be quantified. Data from the geostationary MSG (Meteosat Second Generation) SEVIRI (Spinning Enhanced Visible and Infrared Imager) sensor is well suited for this purpose due to the fixed position of the sensor, the spectral resolution......, including a red and NIR band, and the high temporal resolution (15 min) of data, enabling MSG data to be used as a reference for estimating MODIS surface reflectance and NDVI variations caused by varying sun-sensor geometry. The study was performed on data covering West Africa for periods of lowest possible...

  19. The transiting dust clumps in the evolved disc of the Sun-like UXor RZ Psc

    Science.gov (United States)

    Kennedy, Grant M.; Kenworthy, Matthew A.; Pepper, Joshua; Rodriguez, Joseph E.; Siverd, Robert J.; Stassun, Keivan G.; Wyatt, Mark C.

    2017-01-01

    RZ Psc is a young Sun-like star, long associated with the UXor class of variable stars, which is partially or wholly dimmed by dust clumps several times each year. The system has a bright and variable infrared excess, which has been interpreted as evidence that the dimming events are the passage of asteroidal fragments in front of the host star. Here, we present a decade of optical photometry of RZ Psc and take a critical look at the asteroid belt interpretation. We show that the distribution of light curve gradients is non-uniform for deep events, which we interpret as possible evidence for an asteroidal fragment-like clump structure. However, the clumps are very likely seen above a high optical depth midplane, so the disc's bulk clumpiness is not revealed. While circumstantial evidence suggests an asteroid belt is more plausible than a gas-rich transition disc, the evolutionary status remains uncertain. We suggest that the rarity of Sun-like stars showing disc-related variability may arise because (i) any accretion streams are transparent and/or (ii) turbulence above the inner rim is normally shadowed by a flared outer disc.

  20. Phase Transition Couplings in U(1) and SU(N) Regularized Gauge Theories

    Science.gov (United States)

    Laperashvili, L. V.; Ryzhikh, D. A.; Nielsen, H. B.

    Using a two-loop approximation for β functions, we have considered the corresponding renormalization group improved effective potential in the dual Abelian Higgs model (DAHM) of scalar monopoles and calculated the phase transition (critical) couplings in U(1) and SU(N) regularized gauge theories. In contrast to our previous result αcrit 0.17, obtained in the one-loop approximation with the DAHM effective potential (see Ref. 20), the critical value of the electric fine structure constant in the two-loop approximation, calculated in the present paper, is equal to αcrit 0.208 and coincides with the lattice result for compact QED10: α crit lat≈ 0.20+/- 0.015. Following the 't Hooft's idea of the ``Abelization'' of monopole vacuum in the Yang-Mills theories, we have obtained an estimation of the SU(N) triple point coupling constants, which is α {N, crit}-1= (N)/(2) √ {(N+1)/(N-1)} α { U(1),crit}-1. This relation was used for the description of the Planck scale values of the inverse running constants α i-1(μ ) (i= 1, 2, 3 correspond to U(1), SU(2) and SU(3) groups), according to the ideas of the multiple point model.16

  1. Phase Transition Couplings in U(1) and SU(N) Regulirized Gauge Theories

    CERN Document Server

    Laperashvili, L V; Ryzhikh, D A

    2001-01-01

    Using a 2-loop approximation for $\\beta$-functions, we have considered the corresponding renormalization group improved effective potential in the Dual Abelian Higgs Model (DAHM) of scalar monopoles and calculated the phase transition (critical) couplings in U(1) and SU(N) regularized gauge theories. In contrast to our previous result $\\alpha_{crit} \\approx 0.17$, obtained in the one-loop approximation with the DAHM effective potential (see Ref.[20]), the critical value of the electric fine structure constant in the 2-loop approximation, calculated in the present paper, is equal to $\\alpha_{crit}\\approx 0.208$ and coincides with the lattice result for compact QED [10]: $\\alpha_{crit}^{lat} \\approx 0.20\\pm 0.015$. Following the 't Hooft's idea of the "abelization" of monopole vacuum in the Yang--Mills theories, we have obtained an estimation of the SU(N) triple point coupling constants, which is $\\alpha_{N,crit}^{-1}=\\frac{N}{2}\\sqrt{\\frac{N+1}{N-1}} \\alpha_{U(1),crit}^{-1}$. This relation was used for the des...

  2. The transiting dust clumps in the evolved disc of the Sun-like UXor RZ Psc

    Science.gov (United States)

    Kenworthy, Matthew A.; Pepper, Joshua; Rodriguez, Joseph E.; Siverd, Robert J.; Stassun, Keivan G.; Wyatt, Mark C.

    2017-01-01

    RZ Psc is a young Sun-like star, long associated with the UXor class of variable stars, which is partially or wholly dimmed by dust clumps several times each year. The system has a bright and variable infrared excess, which has been interpreted as evidence that the dimming events are the passage of asteroidal fragments in front of the host star. Here, we present a decade of optical photometry of RZ Psc and take a critical look at the asteroid belt interpretation. We show that the distribution of light curve gradients is non-uniform for deep events, which we interpret as possible evidence for an asteroidal fragment-like clump structure. However, the clumps are very likely seen above a high optical depth midplane, so the disc’s bulk clumpiness is not revealed. While circumstantial evidence suggests an asteroid belt is more plausible than a gas-rich transition disc, the evolutionary status remains uncertain. We suggest that the rarity of Sun-like stars showing disc-related variability may arise because (i) any accretion streams are transparent and/or (ii) turbulence above the inner rim is normally shadowed by a flared outer disc. PMID:28280566

  3. Precise and economic sun position sensor; Ein praeziser und preiswerter Sonnenstandsensor

    Energy Technology Data Exchange (ETDEWEB)

    Haeberle, A.; Luginsland, F.; Zahler, C.; Topor, A. [PSE GmbH, Solar Info Center, Freiburg (Germany); Reetz, C. [Research and Individual Software (RIAP), Freiburg (Germany); Apian-Bennewitz, P. [Pab-Opto, Freiburg (Germany)

    2006-07-01

    We developed a device for quality control and monitoring of sun-tracking systems. Our approach consists of using the long-established shadow principle in combination with commonly available CCD chips. The chips' precision allows for detection accuracy to within well below 1 mrad in relative change of the sun position. First prototypes have been tested successfully. (orig.)

  4. Calibration of of Sun Photometers and Sky Radiance Sensors. Chapter 3

    Science.gov (United States)

    Pietras, Christophe; Miller, Mark; Frouin, Robert; Eck, Tom; Holben, Brent; Marketon, John

    2001-01-01

    The main source of error in retrieving aerosol optical thicknesses using sun photometry comes from the determination of the TOA voltages. The degradation of interference filters is the most important source of the long-term changes in the cross-calibrations. Although major improvements have been made in the design of the filters (interference filters fabricated using ion-assisted deposition), the filters remain the principal factor limiting performance of the sun photometers. Degradation of filters necessitates frequent calibration of sun photometers and frequent measurements of the filter transmission or the relative system response. The degradation of the filters mounted on the CIMEL sun photometers have been monitored since 1993 by the Aerosol Robotic Network (AERONET) project. The decay reported by Holben et al. for the first two years of a CIMEL#s operation is between 1 and 5%. Nevertheless, the filters mounted on CIMEL instruments are regularly replaced after two years of use. The cross-calibration technique consists of taking measurements concurrently with the uncalibrated and the reference sun photometers. While analyzing measurements, the quality of the calibration has to be checked, using the following considerations: (1) any cirrus clouds suspected to be masking the sun, during the calibration period, need to be reported and the corresponding data set removed; and (2) the stability of the day needs to be checked. This chapter will describe calibration techniques, facilities, and protocols used for calibrating sun photometers and sky radiometers.

  5. Luhman 16AB: A Remarkable, Variable L/T Transition Binary 2 pc from the Sun

    CERN Document Server

    Burgasser, A J; Beletsky, Y; Plavchan, P; Gillon, M; Radigan, J; Jehin, E; Delrez, L; Opitom, C; Morrell, N; Osten, R; Street, R; Melis, C; Triaud, A; Simcoe, R

    2013-01-01

    Luhman (2013) has reported the discovery of a brown dwarf binary system only 2.01+/-0.15 pc from the Sun. The binary is well-resolved with a projected separation of 1.5", and spectroscopic observations have identified the components as late-L and early-T dwarfs. The system exhibits several remarkable traits, including a "flux reversal", where the T dwarf is brighter over 0.9-1.3 micron but fainter at other wavelengths; and significant (~10%) short-period (~4.9 hr) photometric variability with a complex light curve. These observations suggest spatial variations in condensate cloud structure, which is known to evolve substantially across the L dwarf/T dwarf transition. Here we report preliminary results from a multi-site monitoring campaign aimed at probing the spectral and temporal properties of this source. Focusing on our spectroscopic observations, we report the first detections of NIR spectral variability, present detailed analysis of K I lines that confirm differences in condensate opacity between the com...

  6. Systematic radial flows in the chromosphere, transition region, and corona of the quiet sun

    Science.gov (United States)

    Hassler, Donald M.; Rottman, Gary J.; Orrall, Frank Q.

    1991-05-01

    An observational study of the systematic radial flows representative of the quiet sun's chromosphere, transition region, and corona is presented. A sounding rocket experiment (July 27, 1987) obtained high-resolution EUV spectra along a solar diameter with spatial resolution of 20 x 20 arcsec. The center-to-limb behavior of four representative lines (Si II 1533 A, Fe II 1563 A, C IV 1548 A, Ne VIII 770 A formed at different heights in the solar atmosphere is discussed. Assuming that horizontal motions cancel statistically so that the line-of-sight velocity approaches zero at the limb, the net radial downflow is approximately 7.5 + or - 1.0 km/s for C IV, 2.7 + or - 1.5 km/s for Fe II 1563 A, and upper limits of 0 + or - 1.2 km/s and 0 + or - 4 km/s for Si II and Ne VIII, respectively. The absolute wavelengths of each emission line were determined by direct comparison with wavelengths of known platinum lines generated by an inflight calibration lamp. The assumption of line-of-sight velocity approaching zero at the limb is then tested by comparing the wavelengths with recently published laboratory rest wavelengths of the solar emission lines.

  7. Review on the Traction System Sensor Technology of a Rail Transit Train.

    Science.gov (United States)

    Feng, Jianghua; Xu, Junfeng; Liao, Wu; Liu, Yong

    2017-06-11

    The development of high-speed intelligent rail transit has increased the number of sensors applied on trains. These play an important role in train state control and monitoring. These sensors generally work in a severe environment, so the key problem for sensor data acquisition is to ensure data accuracy and reliability. In this paper, we follow the sequence of sensor signal flow, present sensor signal sensing technology, sensor data acquisition, and processing technology, as well as sensor fault diagnosis technology based on the voltage, current, speed, and temperature sensors which are commonly used in train traction systems. Finally, intelligent sensors and future research directions of rail transit train sensors are discussed.

  8. Josephson effects in an alternating current biased transition edge sensor

    CERN Document Server

    Gottardi, Luciano; Akamatsu, Hiroki; van der Kuur, Jan; Bruijn, Marcel P; Hartog, Roland H den; Hijmering, Richard; Khosropanah, Pourya; Lambert, Colin; van der Linden, Anton J; Ridder, Marcel L; Suzuki, Toyo; Gao, Jan R

    2016-01-01

    We report the experimental evidence of the ac Josephson effect in a transition edge sensor (TES) operating in a frequency domain multiplexer and biased by ac voltage at MHz frequencies. The effect is observed by measuring the non-linear impedance of the sensor. The TES is treated as a weakly linked superconducting system and within the resistively shunted junction model framework. We provide a full theoretical explanation of the results by finding the analytic solution of the non-inertial Langevian equation of the system and calculating the non-linear response of the detector to a large ac bias current in the presence of noise.

  9. Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

    Science.gov (United States)

    Chervenak, J. A.; Adams, J. A.; Bandler, S. B.; Busch, S. E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, J. P.; Porter, F. S.; Ray, C.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.

    2012-01-01

    We have produced a variety of superconducting transition edge sensor array designs for microcalorimetric detection of x-rays. Arrays are characterized with a time division SQUID multiplexer such that greater than 10 devices from an array can be measured in the same cooldown. Designs include kilo pixel scale arrays of relatively small sensors (-75 micron pitch) atop a thick metal heatsinking layer as well as arrays of membrane-isolated devices on 250 micron and up to 600 micron pitch. We discuss fabrication and performance of microstripline wiring at the small scales achieved to date. We also address fabrication issues with reduction of absorber contact area in small devices.

  10. Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations

    Science.gov (United States)

    Holman, Matthew J.; Fabrycky, Daniel C.; Ragozzine, Darin; Ford, Eric B.; Steffen, Jason H.; Welsh, William F.; Lissauer, Jack J.; Latham, David W.; Marcy, Geoffrey W.; Walkowicz, Lucianne M.; Batalha, Natalie M.; Jenkins, Jon M.; Rowe, Jason F.; Cochran, William D.; Fressin, Francois; Torres, Guillermo; Buchhave, Lars A.; Sasselov, Dimitar D.; Borucki, William J.; Koch, David G.; Basri, Gibor; Brown, Timothy M.; Caldwell, Douglas A.; Charbonneau, David; Dunham, Edward W.; Gautier, Thomas N.; Geary, John C.; Gilliland, Ronald L.; Haas, Michael R.; Howell, Steve B.; Ciardi, David R.; Endl, Michael; Fischer, Debra; Fürész, Gábor; Hartman, Joel D.; Isaacson, Howard; Johnson, John A.; MacQueen, Phillip J.; Moorhead, Althea V.; Morehead, Robert C.; Orosz, Jerome A.

    2010-10-01

    The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection of two Saturn-size planets that transit the same Sun-like star, based on 7 months of Kepler observations. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 minutes per orbit; in addition, the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial-velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two confirmed giant planets, we identified an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

  11. Kepler-9: a system of multiple planets transiting a Sun-like star, confirmed by timing variations.

    Science.gov (United States)

    Holman, Matthew J; Fabrycky, Daniel C; Ragozzine, Darin; Ford, Eric B; Steffen, Jason H; Welsh, William F; Lissauer, Jack J; Latham, David W; Marcy, Geoffrey W; Walkowicz, Lucianne M; Batalha, Natalie M; Jenkins, Jon M; Rowe, Jason F; Cochran, William D; Fressin, Francois; Torres, Guillermo; Buchhave, Lars A; Sasselov, Dimitar D; Borucki, William J; Koch, David G; Basri, Gibor; Brown, Timothy M; Caldwell, Douglas A; Charbonneau, David; Dunham, Edward W; Gautier, Thomas N; Geary, John C; Gilliland, Ronald L; Haas, Michael R; Howell, Steve B; Ciardi, David R; Endl, Michael; Fischer, Debra; Fürész, Gábor; Hartman, Joel D; Isaacson, Howard; Johnson, John A; MacQueen, Phillip J; Moorhead, Althea V; Morehead, Robert C; Orosz, Jerome A

    2010-10-01

    The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection of two Saturn-size planets that transit the same Sun-like star, based on 7 months of Kepler observations. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 minutes per orbit; in addition, the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial-velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two confirmed giant planets, we identified an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

  12. Slug to churn transition analysis using wire-mesh sensor

    Science.gov (United States)

    H. F. Velasco, P.; Ortiz-Vidal, L. E.; Rocha, D. M.; Rodriguez, O. M. H.

    2016-06-01

    A comparison between some theoretical slug to churn flow-pattern transition models and experimental data is performed. The flow-pattern database considers vertical upward air-water flow at standard temperature and pressure for 50 mm and 32 mm ID pipes. A briefly description of the models and its phenomenology is presented. In general, the performance of the transition models is poor. We found that new experimental studies describing objectively both stable and unstable slug flow-pattern are required. In this sense, the Wire Mesh Sensor (WMS) can assist to that aim. The potential of the WMS is outlined.

  13. Design of transition edge sensor microcalorimeters for optimal performance

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R. E-mail: sbandler@milkyway.gsfc.nasa.gov; Figueroa-Feliciano, E.; Stahle, C.K.; Boyce, K.; Brekosky, R.; Chervenak, J.; Finkbeiner, F.; Kelley, R.; Lindeman, M.; Porter, F.S.; Saab, T

    2004-03-11

    We have developed a model for transition edge sensors to optimize performance under a variety of different conditions. There are three design trade-offs when engineering a microcalorimeter for a particular application: energy resolution, energy range and maximum count rate. All three are interdependent and are determined by various design parameters such as the detector heat capacity, the sharpness of the transition, and the thermal conductance of the detector to the frame. Our model includes all known sources of intrinsic noise in our calorimeters including the observed broad band excess noise. We will present the results of this model, and its predictions for optimally designed microcalorimeters.

  14. Towards Ultra-Low-NoiseMoAu Transition Edge Sensors

    CERN Document Server

    Goldie, D J; Glowacka, D M; Withington, S

    2014-01-01

    We report initial measurements on our firstMoAu Transition Edge Sensors (TESs). The TESs formed from a bilayer of 40 nm of Mo and 106 nm of Au showed transition temperatures of about 320 mK, higher than identical TESs with a MoCu bilayer which is consistent with a reduced electron transmission coefficient between the bilayer films. We report measurements of thermal conductance in the 200 nm thick silicon nitride SiNx support structures at this temperature, TES dynamic behaviour and current noise measurements.

  15. Statistical study of network jets observed in the solar transition region: A comparison between coronal holes and quiet sun regions

    CERN Document Server

    Narang, Nancy; Tian, Hui; Banerjee, Dipankar; Cranmer, Steven R; DeLuca, Ed E; McKillop, Sean

    2016-01-01

    Recent IRIS observations have revealed a prevalence of intermittent small-scale jets with apparent speeds of 80 - 250 km s$^{-1}$, emanating from small-scale bright regions inside network boundaries of coronal holes. We find that these network jets appear not only in coronal holes but also in quiet-sun regions. Using IRIS 1330A (C II) slit-jaw images, we extract several parameters of these network jets, e.g. apparent speed, length, lifetime and increase in foot-point brightness. Using several observations, we find that some properties of the jets are very similar but others are obviously different between the quiet sun and coronal holes. For example, our study shows that the coronal-hole jets appear to be faster and longer than those in the quiet sun. This can be directly attributed to a difference in the magnetic configuration of the two regions with open magnetic field lines rooted in coronal holes and magnetic loops often present in quiet sun. We have also detected compact bright loops, likely transition r...

  16. The Hetu'u Global Network: Measuring the Distance to the Sun with the Transit of Venus

    Science.gov (United States)

    Rodriguez, David; Faherty, J.

    2013-01-01

    In the spirit of historic astronomical endeavors, we invited school groups across the globe to collaborate in a solar distance measurement using the 2012 transit of Venus. In total, our group (stationed at Easter Island, Chile) recruited 19 school groups spread over 6 continents and 10 countries to participate in our Hetu’u Global Network. Applying the methods of French astronomer Joseph-Nicolas Delisle, we used individual second and third Venus-Sun contact times to calculate the distance to the Sun. Ten of the sites in our network had amiable weather; 8 of which measured second contact and 5 of which measured third contact leading to consistent solar distance measurements of 152+/-30 million km and 163+/-30 million km respectively. The distance to the Sun at the time of the transit was 152.25 million km; therefore, our measurements are also consistent within 1-sigma of the known value. The goal of our international school group network was to inspire the next generation of scientists using the excitement and accessibility of such a rare astronomical event. In the process, we connected hundreds of participating students representing a diverse, multi-cultural group with differing political, economic, and racial backgrounds.

  17. Optical Sensor for Characterizing the Phase Transition in Salted Solutions

    Science.gov (United States)

    Claverie, Rémy; Fontana, Marc D.; Duričković, Ivana; Bourson, Patrice; Marchetti, Mario; Chassot, Jean-Marie

    2010-01-01

    We propose a new optical sensor to characterize the solid-liquid phase transition in salted solutions. The probe mainly consists of a Raman spectrometer that extracts the vibrational properties from the light scattered by the salty medium. The spectrum of the O – H stretching band was shown to be strongly affected by the introduction of NaCl and the temperature change as well. A parameter SD defined as the ratio of the integrated intensities of two parts of this band allows to study the temperature and concentration dependences of the phase transition. Then, an easy and efficient signal processing and the exploitation of a modified Boltzmann equation give information on the phase transition. Validations were done on solutions with varying concentration of NaCl. PMID:22319327

  18. The Magnetically-Tuned Transition-Edge Sensor

    Science.gov (United States)

    Sadleir, John E.; Lee, Sang-Jun; Smith, Stephen J.; Busch, Sarah E.; Bandler, Simon R.; Adams, Joseph S.; Eckart, Megan E.; Chevenak, James A.; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, Frederick S.; Porst, Jan-Patrick

    2014-01-01

    We present the first measurements on the proposed magnetically-tuned superconducting transition-edge sensor (MTES) and compare the modified resistive transition with the theoretical prediction. A TES's resistive transition is customarily characterized in terms of the unit less device parameters alpha and beta corresponding to the resistive response to changes in temperature and current respectively. We present a new relationship between measured IV quantities and the parameters alpha and beta and use these relations to confirm we have stably biased a TES with negative beta parameter with magnetic tuning. Motivated by access to this new unexplored parameter space, we investigate the conditions for bias stability of a TES taking into account both self and externally applied magnetic fields.

  19. Thin film ruthenium microstructures for transition edge sensors

    Science.gov (United States)

    Ilin, A. S.; Cohn, I. A.; Vystavkin, A. N.; Kovalenko, A. G.

    2016-12-01

    The superconducting properties of ruthenium (Ru) thin films and microstructures are investigated. The microstructures are used as transition edge sensors (TES), working at He-3 evaporation cryostats' temperatures. Ruthenium is substantially inert, and the critical temperature Tc for bulk Ru samples is known from state of art to be 0.40-0.51 K. We investigated magnetron sputtered Ru thin films with thicknesses 13-300 nm on a Si substrate and electron lithography fabricated TES samples, based on the thin-film Ru microstructures. It has been found, that the Tc for the Ru thin films is 0.55-0.70 K, and the width of the transition region is 1-5 mK, and for the Ru TES Tc = 0.55 and ΔT = 4 mK. Furthermore, it was established that lithography process had no significant influence on the properties of the TES samples, so we were able to get consistent properties for several fabrication sessions. Therefore ruthenium is concluded to be a desirable material for transition edge sensors working at He-3 cryostats' temperatures.

  20. SU(N) transitions in M-theory on Calabi-Yau fourfolds and background fluxes

    CERN Document Server

    Jockers, Hans; Morrison, David R; Plesser, M Ronen

    2016-01-01

    We study M-theory on a Calabi-Yau fourfold with a smooth surface $S$ of $A_{N-1}$ singularities. The resulting three-dimensional theory has a $\\mathcal{N}=2$ $SU(N)$ gauge theory sector, which we obtain from a twisted dimensional reduction of a seven-dimensional $\\mathcal{N}=1$ $SU(N)$ gauge theory on the surface $S$. A variant of the Vafa-Witten equations governs the moduli space of the gauge theory, which, for a trivial $SU(N)$ principal bundle over $S$, admits a Coulomb and a Higgs branch. In M-theory these two gauge theory branches arise from a resolution and a deformation to smooth Calabi-Yau fourfolds, respectively. We find that the deformed Calabi-Yau fourfold associated to the Higgs branch requires for consistency a non-trivial four-form background flux in M-theory. The flat directions of the flux-induced superpotential are in agreement with the gauge theory prediction for the moduli space of the Higgs branch. We illustrate our findings with explicit examples that realize the Coulomb and Higgs phase t...

  1. Characterizing the Superconducting-to-Normal Transition in Mo/Au Transition-Edge Sensor Bilayers

    Science.gov (United States)

    Smith, Stephen J.; Bandler, Simon R.; Brown, Ari. -D.; Chervenak, Jay A.; Finkbeiner, Fred M.; Iyomoto, Naoko; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, Frederick S.; Sadleir, John E.

    2007-01-01

    We are developing arrays of Mo/Au bilayer transition-edge sensors (TES's) for applications in future X-ray astronomy missions such as NASA's Constellation-X. The physical properties of the superconducting-to-normal transition in our TES bilayers, while often reproducible and characterized, are not well understood. The addition of normal metal features on top of the bilayer are found to change the shape and temperature of the transition, and they typically reduce the unexplained 'excess' noise. In order to understand and potentially optimize the properties of the transition, we have been studying the temperature, widths and current dependence of these transitions. We report on the characterization of devices both deposited on silicon substrates and suspended on thin silicon nitride membranes. This includes key device parameters such as the logarithmic resistance sensitivity with temperature alpha, and the logarithmic resistance sensitivity with current beta, of the phase-transition. We investigate alpha and beta as a function of current, both at fixed and varying bias points in the transition. Using Ginzburg-Landau theory for the current dependence of the superconducting transition temperature, we investigate the relationship between alpha and beta and compare our measured and theoretical estimates.

  2. Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sadleir, John E.; Smith, Stephen J.; Bandler, Simon R.; Chervenak, James A.; Clem, John R.

    2010-01-29

    We have found experimentally that the critical current of a square thin-film superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T, a behavior that has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. As a consequence, the effective transition temperature T{sub c} of the TES is current dependent and at fixed current scales as 1/L{sup 2}. We have also found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. We have observed the longitudinal proximity effect in these devices over extraordinarily long lengths up to 290 {micro}m, 1450 times the mean-free path.

  3. Longitudinal Proximity Effects in Superconducting Transition-Edge Sensors

    Science.gov (United States)

    Sadleir, John E.; Smith, Stephen J.; Bandler, Simon R.; Chervenak, James A.; Clem, John R.

    2010-01-01

    We have found experimentally that the critical current of a square thin-film superconducting transition-edge sensor (TES) depends exponentially upon the side length L and the square root of the temperature T, a behavior that has a natural theoretical explanation in terms of longitudinal proximity effects if the TES is regarded as a weak link between superconducting leads. As a consequence, the effective transition temperature T(sub c) of the TES is current-dependent and at fixed current scales as 1/L(sup 2). We also have found that the critical current can show clear Fraunhofer-like oscillations in an applied magnetic field, similar to those found in Josephson junctions. We have observed the longitudinal proximity effect in these devices over extraordinarily long lengths up to 290 micrometers, 1450 times the mean-free path.

  4. Position-sensitive transition edge sensor modeling and results

    Energy Technology Data Exchange (ETDEWEB)

    Hammock, Christina E-mail: chammock@milkyway.gsfc.nasa.gov; Figueroa-Feliciano, Enectali; Apodaca, Emmanuel; Bandler, Simon; Boyce, Kevin; Chervenak, Jay; Finkbeiner, Fred; Kelley, Richard; Lindeman, Mark; Porter, Scott; Saab, Tarek; Stahle, Caroline

    2004-03-11

    We report the latest design and experimental results for a Position-Sensitive Transition-Edge Sensor (PoST). The PoST is motivated by the desire to achieve a larger field-of-view without increasing the number of readout channels. A PoST consists of a one-dimensional array of X-ray absorbers connected on each end to a Transition Edge Sensor (TES). Position differentiation is achieved through a comparison of pulses between the two TESs and X-ray energy is inferred from a sum of the two signals. Optimizing such a device involves studying the available parameter space which includes device properties such as heat capacity and thermal conductivity as well as TES read-out circuitry parameters. We present results for different regimes of operation and the effects on energy resolution, throughput, and position differentiation. Results and implications from a non-linear model developed to study the saturation effects unique to PoSTs are also presented.

  5. Heating the sun's lower transition region with fine-scale electric currents

    Science.gov (United States)

    Rabin, D.; Moore, R.

    1984-01-01

    Analytical and observational data are presented to show that the lower transition zone, a 100 km thick region at 10,000-200,000 K between the solar chromosphere and corona, is heated by local electric currents. The study was spurred by correlations between the enhanced atmospheric heating and magnetospheric flux in the chromospheric network and active regions. Field aligned current heated flux loops are asserted to mainly reside in and make up most of the transition region. It is shown that thermal conduction from the sides of hot gas columns generated by the current dissipation is the source of the observed temperature distribution in the transition regions.

  6. Proximity Effects and Nonequilibrium Superconductivity in Transition-Edge Sensors

    Science.gov (United States)

    Sadleir, John E.; Smith, Stephen J.; Robinson, Ian K.; Finkbeiner, Fred M.; Chervenak, James A.; Bandler, Simon R.; Eckart, Megan E.; Kilbourne, Caroline A.

    2011-01-01

    We have recently shown that normal-metal/superconductor (N/S) bilayer TESs (superconducting Transition-Edge Sensors) exhibit weak-link behavior.l Here we extend our understanding to include TESs with added noise-mitigating normal-metal structures (N structures). We find TESs with added Au structures also exhibit weak-link behavior as evidenced by exponential temperature dependence of the critical current and Josephson-like oscillations of the critical current with applied magnetic field. We explain our results in terms of an effect converse to the longitudinal proximity effect (LoPE) 1, the lateral inverse proximity effect (LaiPE), for which the order parameter in the N/S bilayer is reduced due to the neighboring N structures. Resistance and critical current measurements are presented as a function of temperature and magnetic field taken on square Mol Au bilayer TESs with lengths ranging from 8 to 130 {\\mu}m with and without added N structures. We observe the inverse proximity effect on the bilayer over in-plane distances many tens of microns and find the transition shifts to lower temperatures scale approximately as the inverse square of the in- plane N-structure separation distance, without appreciable broadening of the transition width. We also present evidence for nonequilbrium superconductivity and estimate a quasiparticle lifetime of 1.8 \\times 10-10 s for the bilayer. The LoPE model is also used to explain the increased conductivity at temperatures above the bilayer's steep resistive transition.

  7. Conclusive quantum steering with superconducting transition edge sensors

    CERN Document Server

    Smith, Devin H; de Almeida, Marcelo; Branciard, Cyril; Fedrizzi, Alessandro; Weinhold, Till J; Lita, Adriana; Calkins, Brice; Gerrits, Thomas; Nam, Sae Woo; White, Andrew G

    2011-01-01

    Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices to cheat by hiding unfavorable events in losses. Here we close this "detection loophole" by combining a highly efficient source of entangled photon pairs with superconducting transition edge sensors. We achieve an unprecedented $\\sim$62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 standard deviations. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.

  8. Electrical Characteristics of Superconducting Ti Transition Edge Sensors

    Science.gov (United States)

    Zhang, W.; Zhong, J. Q.; Miao, W.; Wang, Z.; Liu, D.; Yao, Q. J.; Shi, S. C.; Chen, T. J.; Wang, M. J.

    2016-07-01

    We have designed and fabricated superconducting Ti transition edge sensors (TES) with different microbridge lengths varying from 1 to 6 \\upmu m. The current-voltage characteristics of the fabricated Ti TESs are measured at different bath temperatures using a commercial SQUID amplifier. The thermal conductance ( G) is found to be about 300 pW/K for a 2.6-\\upmu m-long device. In addition, the effective response time measured with a current pulse signal is about 3 \\upmu s, and decreases with increasing the bias voltage because of negative electro-thermal feedback. The obtained electrical noise equivalent power from the measured current noise is about 4 × 10^{-17} W/Hz^{0.5}, which is sufficiently low for TeSIA instrument.

  9. Superconducting transition edge sensors and methods for design and manufacture thereof

    Science.gov (United States)

    Sadleir, John E. (Inventor)

    2013-01-01

    Methods for forming sensors using transition edge sensors (TES) and sensors therefrom are described. The method includes forming a plurality of sensor arrays includes at least one TES device. The TES device includes a TES device body, a first superconducting lead contacting a first portion of the TES device body, and a second superconducting lead contacting of a second portion of the TES device body, where the first and second superconducting leads separated on the TES device body by a lead spacing. The lead spacing can be selected to be different for at least two of the plurality of sensor arrays. The method also includes determining a transition temperature for each of the plurality of sensor arrays and generating a signal responsive to detecting a change in the electrical characteristics of one of the plurality of sensor arrays meeting a transition temperature criterion.

  10. Unexpected Nonlinear Effects in Superconducting Transition-Edge Sensors

    Science.gov (United States)

    Sadleir, John

    2016-01-01

    When a normal metal transitions into the superconducting state the DC resistance drops from a finite value to zero over some finite transition width in temperature, current, and magnetic field. Superconducting transition-edge sensors (TESs) operate within this transition region and uses resistive changes to measure deposited thermal energy. This resistive transition is not perfectly smooth and a wide range of TES designs and materials show sub-structure in the resistive transition (as seen in smooth nonmonotonic behavior, jump discontinuities, and hysteresis in the devices current-voltage relation and derivatives of the resistance with respect to temperature, bias current, and magnetic field). TES technology has advanced to the point where for many applications this structure is the limiting factor in performance and optimization consists of finding operating points away from these structures. For example, operating at or near this structure can lead to nonlinearity in the detectors response and gain scale, limit the spectral range of the detector by limiting the usable resistive range, and degrade energy resolution. The origin of much of this substructure is unknown. This presentation investigates a number of possible sources in turn. First we model the TES as a superconducting weak-link and solve for the characteristic differential equations current and voltage time dependence. We find:(1) measured DC biased current-voltage relationship is the time-average of a much higher frequency limit cycle solution.(2) We calculate the fundamental frequency and estimate the power radiated from the TES treating the bias leads as an antennae.(3) The solution for a set of circuit parameters becomes multivalued leading to current transitions between levels.(4)The circuit parameters can change the measure resistance and mask the true critical current. As a consequence the TES resistance surface is not just a function of temperature, current, and magnetic field but is also a

  11. Bosonization in SU(N) Gauge Field Theory in Terms of Phase Transition of Second Kind

    CERN Document Server

    Koshelkin, A V

    2012-01-01

    Bosonization of the strong interacting matter as a process of arising observable hadrons is studied in terms of the phase transition of the second kind. The spectrum of bosons which is free from the zero point energy is derived . The calculated boson mass is found to depend self-consistently on both the amplitude of a gauge field and quark mass. In the framework of the quasi-classical model a hadron mass is calculated in the case of bosonization into pions.

  12. Transition edge sensors with few-mode ballistic thermal isolation

    Science.gov (United States)

    Osman, D.; Withington, S.; Goldie, D. J.; Glowacka, D. M.

    2014-08-01

    We have fabricated Transition Edge Sensors (TESs) whose thermal characteristics are completely characterised by few-mode ballistic phonon exchange with the heat bath. These TESs have exceptionally small amorphous SiNx support legs: 0.2 μm thick, 0.7-1.0 μm wide, and 1.0 to 4.0 μm long. We show, using classical elastic wave theory, that it is only necessary to know the geometry and bulk elastic constants of the material to calculate the thermal conductance and fluctuation noise. Our devices operate in the few-mode regime, between 5 and 7 modes per leg, and have noise equivalent powers (NEPs) of 1.2 aW Hz-1/2. The NEP is dominated by the thermal fluctuation noise in the legs, which itself is dominated by phonon shot-noise. Thus, TESs have been demonstrated whose thermal characteristics are fully accounted for by an elastic noise-wave model. Our current devices, and second-generation devices based on patterned phononic filters, can be used to produce optically compact, mechanically robust, highly sensitive TES imaging arrays, circumventing many of the problems inherent in conventional long-legged designs.

  13. AlMn Transition Edge Sensors for Advanced ACTPol

    Science.gov (United States)

    Li, Dale; Austermann, Jason E.; Beall, James A.; Becker, Daniel T.; Duff, Shannon M.; Gallardo, Patricio A.; Henderson, Shawn W.; Hilton, Gene C.; Ho, Shuay-Pwu; Hubmayr, Johannes; Koopman, Brian J.; McMahon, Jeffrey J.; Nati, Federico; Niemack, Michael D.; Pappas, Christine G.; Salatino, Maria; Schmitt, Benjamin L.; Simon, Sara M.; Staggs, Suzanne T.; Van Lanen, Jeff; Ward, Jonathan T.; Wollack, Edward J.

    2016-07-01

    Advanced ACTPol (AdvACT) will use an array of multichroic polarization-sensitive AlMn transition edge sensor (TES) bolometers read out through time-division multiplexing. Aluminum doped with a low concentration of manganese can be deposited to a bulk film thickness for a more reliable superconducting critical temperature uniformity compared to thin bilayers. To build the TES, the AlMn alloy is deposited, over Nb wiring, to a specific thickness to set the TES normal resistance. The doping concentration of manganese coarsely defines the TES critical temperature, while a fine tuning is achieved by heating the deposited film to a specific temperature. The TES island is connected to the thermal bath via four silicon-nitride membranes, where their geometry defines the thermal conductance to the temperature of the bath. Lastly, the TES heat capacity is increased by addition of PdAu electrically connected to the AlMn film. Designs and performance characteristics of these AlMn TESs are presented for use in AdvACT.

  14. Iridium thin films deposited via pulsed laser deposition for future applications as transition-edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Galeazzi, M. E-mail: galeazzi@physics.miami.edu; Chen, C.; Cohn, J.L.; Gundersen, J.O

    2004-03-11

    The University of Miami has recently started developing and studying high-resolution microcalorimeters operating near 100 mK for X-ray and particle physics and astrophysics. These detectors will be based on Transition Edge Sensors technology fabricated using iridium thin films deposited via the Pulsed Laser Deposition technique. We report here the preliminary result of the room temperature characterization of the Ir thin films, and an overview of future plans to use the films as transition edge sensors.

  15. The laminar separation sensor - An advanced transition measurement method for use in wind tunnels and flight

    Science.gov (United States)

    Manuel, G. S.; Carraway, D. L.; Croom, C. C.

    1987-01-01

    Wind tunnel and flight tests have recently been conducted by the NASA Langley Research Center to explore the ability of laminar separation hot-film sensors to identify the presence of laminar separation as the principal mode of instability amplification leading to transition. This paper describes the different sensor configurations evaluated during the course of testing and presents results from the flight and wind tunnel evaluations. Plans for the next generation of sensors are briefly discussed.

  16. A New Fluorescent Sensor for Transition Metal Ions in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new fluorescent sensor consisted of fluorenyl and dioxotetraaza unit, namely, 2,10-dimethyl-6-(9-fluorenyl)-1,4,8,11-tetraazaundencane-5,7-dione (L), was synthesized. It is a fluorescent sensor for transition metal ions in aqueous solution.

  17. Day the world discovered the sun an extraordinary story of scientific adventure and the race to track the transit of Venus

    CERN Document Server

    Anderson, Mark

    2012-01-01

    On June 3, 1769, the planet Venus briefly passed across the face of the sun in a cosmic alignment that occurs twice per century. Anticipation of the rare celestial event sparked a worldwide competition among aspiring global superpowers, each sending their own scientific expeditions to far-flung destinations to time the planet's trek. These pioneers used the ?Venus Transit" to discover the physical dimensions of the solar system and refine the methods of discovering longitude at sea. In this fast-paced narrative, Mark Anderson reveals the stories of three Venus Transit voyages--to the heart

  18. Matrix sun sensor design with MCU%基于单片机的矩阵式太阳敏感器设计

    Institute of Scientific and Technical Information of China (English)

    仉英旭; 徐涛; 刘其然

    2016-01-01

    Matrix type sun sensor system is a sensitive system with high precision, high measurement information and fast processing. In this paper, the designed matrix sun sensor using photo-resistors as the sensitive element, the photo-resistors are arranged in a 4 × 4 matrix, the slit type optical head is used to acquire the digital information of two-axis attitude angle; The ADC0809 converts the analog signals to digital signals; The microcontroller unit (MCU) STC89C52 is used to process the signal and output the sensing results to LCD unit. Meanwhile, the results are transferred to the PC by serial port. The experimental results show that the sun sensor has a certain precision, can meet the sun's angle measurement in a certain range.%矩阵式太阳敏感器系统是精度高、测量信息量大并能快速处理的敏感系统。文章设计的矩阵式太阳敏感器,利用光敏电阻作为敏感元件,将光敏电阻排列成4×4矩阵,采用狭缝式光学头部,同时采集到两个轴姿态夹角的数字信息;利用ADC0809对光敏电阻的信号进行模数转换,由单片机STC89C52实现数据的采集和处理,将结果在LCD液晶显示器显示,同时通过串口将结果传输到上位机。实验结果表明,该太阳敏感器具有一定的精度,在一定范围内能够满足太阳的角度测量。

  19. The Hetu'u Global Network: Measuring the Distance to the Sun Using the June 5th/6th Transit of Venus

    CERN Document Server

    Faherty, Jacqueline K; Miller, Scott T

    2012-01-01

    In the spirit of historic astronomical endeavors, we invited school groups across the globe to collaborate in a solar distance measurement using the rare June 5/6th transit of Venus. In total, we recruited 19 school groups spread over 6 continents and 10 countries to participate in our Hetu'u Global Network. Applying the methods of French astronomer Joseph-Nicolas Delisle, we used individual second and third Venus-Sun contact times to calculate the distance to the Sun. Ten of the sites in our network had amiable weather; 8 of which measured second contact and 5 of which measured third contact leading to consistent solar distance measurements of 152+/-30 million km and 163+/-30 million km respectively. The distance to the Sun at the time of the transit was 152.25 million km; therefore, our measurements are also consistent within 1sigma of the known value. The goal of our international school group network was to inspire the next generation of scientists using the excitement and accessibility of a rare astronom...

  20. Sun Allergy

    Science.gov (United States)

    ... if you have unusual, bothersome skin reactions after exposure to sunlight. For severe or persistent symptoms, you may need ... m. when the sun is brightest. Avoid sudden exposure to lots of sunlight. Many people have sun allergy symptoms when they ...

  1. Current-biased Transition-edge Sensors Based on Re-entrant Superconductors

    Science.gov (United States)

    Gulian, A.; Nikoghosyan, V.; Tollaksen, J.; Vardanyan, V.; Kuzanyan, A.

    Transition-edge sensors are widely recognized as one of the most sensitive tools for the photon and particles detection in many areas, from astrophysics to quantum computing. Their application became practical after understanding that rather than being biased in a constant current mode, they should be biased in a constant voltage mode. Despite the methods of voltage biasing of these sensors are well developed since then, generally the current biasing is more convenient for superconducting circuits. Thus transition-edge sensors designed inherently to operate in the current-biased mode are desirable. We developed a design for such detectors based on re-entrant superconductivity. In this case constant current biasing takes place in the normal state, below the superconducting transition, so that following the absorption of a photon it does not yield a latching. Rather, the sensor gains energy and shifts towards the lower resistant (e.g., superconducting) state, and then cools down faster (since Joule heating is now reduced), and resets in a natural way to be able to detect the next photon. We prototyped this kind of transition edge sensors and tested them operational in accordance with the outlined physics. The samples used in experiments were modified compositions of YBCO-superconductors in a ceramic form (which, as we discovered, reproducibly demonstrates re-entrant superconductivity). In this presentation we report their composition, methods of preparation, and the detection results. This approach, in some areas, may have practical advantage over the traditional voltage-biased devices.

  2. Measurement of quasiparticle transport in aluminum films using tungsten transition-edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Yen, J. J., E-mail: jeffyen@stanford.edu; Shank, B.; Cabrera, B.; Moffatt, R.; Redl, P. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Young, B. A.; Tortorici, E. C. [Department of Physics, Santa Clara University, Santa Clara, California 95053 (United States); Brink, P. L.; Cherry, M.; Tomada, A. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Kreikebaum, J. M. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Department of Physics, Santa Clara University, Santa Clara, California 95053 (United States)

    2014-10-20

    We report on experimental studies of phonon sensors which utilize quasiparticle diffusion in thin aluminum films connected to tungsten transition-edge-sensors (TESs) operated at 35 mK. We show that basic TES physics and a simple physical model of the overlap region between the W and Al films in our devices enables us to accurately reproduce the experimentally observed pulse shapes from x-rays absorbed in the Al films. We further estimate quasiparticle loss in Al films using a simple diffusion equation approach. These studies allow the design of phonon sensors with improved performance.

  3. Results of the Laser Sensor Technology Transition Investigation

    Science.gov (United States)

    1992-06-01

    Dr. Richard Preston ’ _KICTE-EP.9199zu APPROE FOR PUBLIC RELEAS, DITRIBUTKON UNL/MITED This effort was funded totally by the Laboratory Director’s...TRANSITION C - F30602-88-D-0026 INVESTIGATION Task 47 PE - 61101F .AUTHOR( PR - LDFP Dr. Richard Preston TA- 08 WU - H0 7. PERFORMING ORGANIZATION NAME(S

  4. Design and implementation of a Sun tracker with a dual-axis single motor for an optical sensor-based photovoltaic system.

    Science.gov (United States)

    Wang, Jing-Min; Lu, Chia-Liang

    2013-03-06

    The dual threats of energy depletion and global warming place the development of methods for harnessing renewable energy resources at the center of public interest. Solar energy is one of the most promising renewable energy resources. Sun trackers can substantially improve the electricity production of a photovoltaic (PV) system. This paper proposes a novel design of a dual-axis solar tracking PV system which utilizes the feedback control theory along with a four-quadrant light dependent resistor (LDR) sensor and simple electronic circuits to provide robust system performance. The proposed system uses a unique dual-axis AC motor and a stand-alone PV inverter to accomplish solar tracking. The control implementation is a technical innovation that is a simple and effective design. In addition, a scaled-down laboratory prototype is constructed to verify the feasibility of the scheme. The effectiveness of the Sun tracker is confirmed experimentally. To conclude, the results of this study may serve as valuable references for future solar energy applications.

  5. Design and Implementation of a Sun Tracker with a Dual-Axis Single Motor for an Optical Sensor-Based Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Chia-Liang Lu

    2013-03-01

    Full Text Available The dual threats of energy depletion and global warming place the development of methods for harnessing renewable energy resources at the center of public interest. Solar energy is one of the most promising renewable energy resources. Sun trackers can substantially improve the electricity production of a photovoltaic (PV system. This paper proposes a novel design of a dual-axis solar tracking PV system which utilizes the feedback control theory along with a four-quadrant light dependent resistor (LDR sensor and simple electronic circuits to provide robust system performance. The proposed system uses a unique dual-axis AC motor and a stand-alone PV inverter to accomplish solar tracking. The control implementation is a technical innovation that is a simple and effective design. In addition, a scaled-down laboratory prototype is constructed to verify the feasibility of the scheme. The effectiveness of the Sun tracker is confirmed experimentally. To conclude, the results of this study may serve as valuable references for future solar energy applications.

  6. The Earth transiting the Sun as seen from Jupiter's moons: detection of an inverse Rossiter-McLaughlin effect produced by the Opposition Surge of the icy Europa

    CERN Document Server

    Molaro, Paolo; Monaco, Lorenzo; Zaggia, Simone; Lovis, Christophe

    2015-01-01

    We report on a multi-wavelength observational campaign which followed the Earth's transit on the Sun as seen from Jupiter on 5 Jan the 2014. Simultaneous observations of Jupiter's moons Europa and Ganymede obtained with HARPS from La Silla, Chile, and HARPS-N from La Palma, Canary Islands, were performed to measure the Rossiter-McLaughlin effect due to the Earth's passage using the same technique successfully adopted for the 2012 Venus Transit (Molaro et al 2013). The expected modulation in radial velocities was of about 20 cm/s but an anomalous drift as large as 38 m/s, i.e. more than two orders of magnitude higher and opposite in sign, was detected instead. The consistent behaviour of the two spectrographs rules out instrumental origin of the radial velocity drift and BiSON observations rule out the possible dependence on the Sun's magnetic activity. We suggest that this anomaly is produced by the Opposition Surge on Europa's icy surface, which amplifies the intensity of the solar radiation from a portion o...

  7. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    Science.gov (United States)

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  8. The Earth transiting the Sun as seen from Jupiter's moons: detection of an inverse Rossiter-McLaughlin effect produced by the opposition surge of the icy Europa

    Science.gov (United States)

    Molaro, P.; Barbieri, M.; Monaco, L.; Zaggia, S.; Lovis, C.

    2015-10-01

    We report on a multiwavelength observational campaign which followed the Earth's transit on the Sun as seen from Jupiter on 2014 January 2014. Simultaneous observations of Jupiter's moons Europa and Ganymede obtained with high accuracy radial velocity planetary searcher (HARPS) from La Silla, Chile and HARPS-N from La Palma, Canary Islands were performed to measure the Rossiter-McLaughlin effect due to the Earth's passage using the same technique successfully adopted for the 2012 Venus Transit. The expected modulation in radial velocities was of ≈20 cm s-1 but an anomalous drift as large as ≈38 m s-1, i.e. more than two orders of magnitude higher and opposite in sign, was detected instead. The consistent behaviour of the two spectrographs rules out instrumental origin of the radial velocity drift and Birmingham Solar Oscillations Network observations rule out the possible dependence on the Sun's magnetic activity. We suggest that this anomaly is produced by the opposition surge on Europa's icy surface, which amplifies the intensity of the solar radiation from a portion of the solar surface centred around the crossing Earth which can then be observed as a sort of inverse Rossiter-McLaughlin effect. in fact, a simplified model of this effect can explain in detail most features of the observed radial velocity anomalies, namely the extensions before and after the transit, the small differences between the two observatories and the presence of a secondary peak closer to Earth passage. This phenomenon, observed here for the first time, should be observed every time similar Earth alignments occur with rocky bodies without atmospheres. We predict that it should be observed again during the next conjunction of Earth and Jupiter in 2026.

  9. Measurement Of Quasiparticle Transport In Aluminum Films Using Tungsten Transition-Edge Sensors

    CERN Document Server

    Yen, J J; Young, B A; Cabrera, B; Brink, P L; Cherry, M; Kreikebaum, J M; Moffatt, R; Redl, P; Tomada, A; Tortorici, E C

    2014-01-01

    We report new experimental studies to understand the physics of phonon sensors which utilize quasiparticle diffusion in thin aluminum films into tungsten transition-edge-sensors (TESs) operated at 35 mK. We show that basic TES physics and a simple physical model of the overlap region between the W and Al films in our devices enables us to accurately reproduce the experimentally observed pulse shapes from x-rays absorbed in the Al films. We further estimate quasiparticle loss in Al films using a simple diffusion equation approach.

  10. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  11. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  12. Monte Carlo Comparisons to a Cryogenic Dark Matter Search Detector with low Transition-Edge-Sensor Transition Temperature

    CERN Document Server

    Leman, S W; Brink, P L; Cabrera, B; Cherry, M; Silva, E Do Couto E; Figueroa-Feliciano, E; Kim, P; Mirabolfathi, N; Pyle, M; Resch, R; Sadoulet, B; Serfass, B; Sundqvist, K M; Tomada, A; Young, B A

    2011-01-01

    We present results on phonon quasidiffusion and Transition Edge Sensor (TES) studies in a large, 3 inch diameter, 1 inch thick [100] high purity germanium crystal, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare calibration data with results from a Monte Carlo which includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels. The phonon energy is then parsed into TES based phonon readout channels and input into a TES simulator.

  13. Characterization and reduction of noise in Mo/Au transition edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lindeman, Mark A. E-mail: lindeman1@gsfc.nasa.gov; Bandler, Simon; Brekosky, Regis P.; Chervenak, James A.; Figueroa-Feliciano, Enectali; Finkbeiner, Fred M.; Saab, Tarek; Stahle, Caroline K

    2004-03-11

    We measured noise in a variety of Mo/Au transition-edge sensor (TES) X-ray calorimeters. We investigated the relationship between the noise, bias, and the superconducting phase transition in the TESs. Our square TES calorimeters have achieved very good energy resolutions (2.4 eV at 1.5 keV) but their resolutions have been limited by broadband white excess noise generated by the TES when it is biased in the phase transition. We have recently fabricated Mo/Cu TESs with interdigitated normal metal bars deposited on top of the bilayer. The new TES calorimeters have demonstrated little or no excess noise in the phase transition. These results point the way to development of TES calorimeters with higher energy resolution.

  14. Investigation of Surface Roughness Effect on Transition Edge Sensor Microcalorimeters Using Multilayer Readout Wiring

    Science.gov (United States)

    Kuromaru, G.; Kuwabara, K.; Miyazaki, N.; Suzuki, S.; Hosoya, S.; Koizumi, Y.; Ohashi, T.; Ishisaki, Y.; Ezoe, Y.; Yamada, S.; Mitsuda, K.; Hidaka, M.; Satoh, T.

    2016-07-01

    We are developing a transition edge sensor (TES) using multilayer readout wiring for future X-ray astronomy satellites. Although we fabricated a first full 20 × 20 pixels TES array, we could not confirm transition of the TES. Considering possible causes, we focused on surface roughness of the TES film. We checked the fabrication process steps that can influence the surface roughness step by step, and changed wiring material (Al to Nb) and also a process condition of an ion milling. As a result, we succeeded to reduce the surface roughness from 4.5 to 2.5 nm rms at 1 \\upmu m scale. However, the transition was not observed probably because the TES films in our samples with surface roughness more than {˜ }1 nm rms tend not to show the transition. Therefore, to suppress the surface roughness even more, we discuss possible process effects and mitigations.

  15. A Study of Al-Mn Transition Edge Sensor Engineering for Stability

    CERN Document Server

    George, E M; Beall, J A; Becker, D; Benson, B A; Bleem, L E; Carlstrom, J E; Chang, C L; Cho, H- M; Crites, A T; Dobbs, M A; Everett, W; Halverson, N W; Henning, J W; Hilton, G C; Holzapfel, W L; Hubmayr, J; Irwin, K D; Li, D; Lueker, M; McMahon, J J; Mehl, J; Montgomery, J; Natoli, T; Nibarger, J P; Niemack, M D; Novosad, V; Ruhl, J E; Sayre, J T; Shirokoff, E; Story, K T; Wang, G; Yefremenko, V; Yoon, K W; Young, E

    2013-01-01

    The stability of Al-Mn transition edge sensor (TES) bolometers is studied as we vary the engineered TES transition, heat capacity, and/or coupling between the heat capacity and TES. We present thermal structure measurements of each of the 39 designs tested. The data is accurately fit by a two-body bolometer model, which allows us to extract the basic TES parameters that affect device stability. We conclude that parameters affecting device stability can be engineered for optimal device operation, and present the model parameters extracted for the different TES designs.

  16. Characterizing Weak-Link Effects in Mo/Au Transition-Edge Sensors

    Science.gov (United States)

    Smith, Stephen

    2011-01-01

    We are developing Mo/Au bilayer transition-edge sensors (TESs) for applications in X-ray astronomy. Critical current measurements on these TESs show they act as weak superconducting links exhibiting oscillatory, Fraunhofer-like, behavior with applied magnetic field. In this contribution we investigate the implications of this behavior for TES detectors, under operational bias conditions. This includes characterizing the logarithmic resistance sensitivity with temperature, (alpha, and current, beta, as a function of applied magnetic field and bias point within the resistive transition. Results show that these important device parameters exhibit similar oscillatory behavior with applied magnetic field, which in turn affects the signal responsivity, noise and energy resolution.

  17. Mitochondrial DNA copy number - but not a mitochondrial tandem CC to TT transition - is increased in sun-exposed skin.

    Science.gov (United States)

    Gebhard, Daniel; Mahler, Bettina; Matt, Katja; Burger, Katharina; Bergemann, Jörg

    2014-03-01

    Mitochondrial DNA (mtDNA) mutations are causatively associated with photo-ageing and are used as biomarkers of UV exposure. The most prominent mitochondrial mutation is the common deletion (CD), which is induced in many tissues by oxidative stress. More photo-specific mutations might be CC to TT tandem transitions which arise from UV-induced cyclobutane pyrimidine dimers. As nucleotide excision repair is absent in mitochondria, this DNA damage can presumably not be repaired resulting in high mitochondrial mutation levels. Here, we analysed levels of the CD, a mitochondrial and a chromosomal tandem transition in epidermis and dermis from exposed and less UV-exposed skin. We also analysed mtDNA copy number, for which changes as a result of oxidative stress have been described in different experimental settings. Whereas mitochondrial tandem transition levels were surprisingly low with no discernible correlation with UV exposure, mtDNA copy number and CD were significantly increased in UV-exposed samples.

  18. Characterisation and modelling of transition edge sensor distributed read-out imaging devices

    Science.gov (United States)

    Smith, Stephen J.; Whitford, Chris H.; Fraser, George W.; Goldie, David J.

    2006-04-01

    We report on the experimental characterisation and modelling of Transition Edge Sensor (TES)-based Distributed Read-Out Imaging Devices (DROIDs), for use as position-sensitive detectors in X-ray astronomy. Latest experimental results from prototype DROIDs using Ir TESs with Au absorbers are reported. Through modelling and the development of signal processing algorithms we are able to design the DROID for optimum spectral and spatial resolution depending upon application.

  19. Characterisation and modelling of transition edge sensor distributed read-out imaging devices

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Stephen J. [Department of Physics and Astronomy, Space Research Centre, Leicester University, Michael Atiyah Building, University Road, Leicester, LE1 7RH (United Kingdom)]. E-mail: sts@star.le.ac.uk; Whitford, Chris H. [Department of Physics and Astronomy, Space Research Centre, Leicester University, Michael Atiyah Building, University Road, Leicester, LE1 7RH (United Kingdom); Fraser, George W. [Department of Physics and Astronomy, Space Research Centre, Leicester University, Michael Atiyah Building, University Road, Leicester, LE1 7RH (United Kingdom); Goldie, David J. [Astrophysics Group, Cavendish Laboratory, Department of Physics, Cambridge University, Madingley Road Cambridge, CB3 OHE (United Kingdom)

    2006-04-15

    We report on the experimental characterisation and modelling of Transition Edge Sensor (TES)-based Distributed Read-Out Imaging Devices (DROIDs), for use as position-sensitive detectors in X-ray astronomy. Latest experimental results from prototype DROIDs using Ir TESs with Au absorbers are reported. Through modelling and the development of signal processing algorithms we are able to design the DROID for optimum spectral and spatial resolution depending upon application.

  20. Simulations of Noise in Phase-Separated Transition-Edge Sensors for SuperCDMS

    CERN Document Server

    Anderson, A J; Pyle, M; Figueroa-Feliciano, E; McCarthy, K; Doughty, T; Cherry, M; Young, B

    2011-01-01

    We briefly review a simple model of superconducting-normal phase-separation in transition-edge sensors in the SuperCDMS experiment. After discussing some design considerations relevant to the TES in the detectors, we study noise sources in both the phase-separated and phase-uniform cases. Such simulations are valuable for optimizing the critical temperature and TES length of future SuperCDMS detectors.

  1. Transition-Edge Sensors for Particle Induced X-ray Emission Measurements

    CERN Document Server

    Palosaari, M R J; Julin, J; Laitinen, M; Napari, M; Sajavaara, T; Doriese, W B; Fowler, J; Reintsema, C; Swetz, D; Schmidt, D; Ullom, J; Maasilta, I J

    2013-01-01

    In this paper we present a new measurement setup, where a transitionedge sensor detector array is used to detect X-rays in particle induced X-ray emission measurements with a 2 MeV proton beam. Transition-edge sensors offer orders of magnitude improvement in energy resolution compared to conventional silicon or germanium detectors, making it possible to recognize spectral lines in materials analysis that have previously been impossible to resolve, and to get chemical information from the elements. Our sensors are cooled to the operation temperature (65 mK) with a cryogen-free adiabatic demagnetization refrigerator, which houses a specially designed X-ray snout that has a vacuum tight window to couple in the radiation. For the best pixel, the measured instrumental energy resolution was 3.06 eV full width at half maximum at 5.9 keV.We discuss the current status of the project, benefits of transition-edge sensors when used in particle induced X-ray emission spectroscopy, and the results from the first measuremen...

  2. Sun meter

    Science.gov (United States)

    Younskevicius, Robert E.

    1978-01-01

    A simple, inexpensive device for measuring the radiation energy of the sun impinging on the device. The measurement of the energy over an extended period of time is accomplished without moving parts or tracking mechanisms.

  3. The Sun

    CERN Document Server

    Golub, Leon

    2017-01-01

    Essential for life on earth and a major influence on our environment, the Sun is also the most fascinating object in the daytime sky. Every day we feel the effect of its coming and going – literally the difference between day and night. But figuring out what the Sun is, what it’s made of, why it glows so brightly, how old it is, how long it will last – all of these take thought and observation. Leon Golub and Jay M. Pasachoff offer an engaging and informative account of what scientists know about the Sun, and the history of these discoveries. Solar astronomers have studied the Sun over the centuries both for its intrinsic interest and in order to use it as a laboratory to reveal the secrets of other stars. The authors discuss the surface of the Sun, including sunspots and their eleven-year cycle, as well as the magnetism that causes them; the Sun’s insides, as studied mainly from seismic waves that astronomers record on its surface; the outer layers of the Sun that we see from Earth only at eclipses ...

  4. First results from Mo/Au transition-edge sensor X-ray calorimeters

    Science.gov (United States)

    Stahle, C. K.; Finkbeiner, F. M.; Boyce, K. R.; Chen, T.; Figueroa Feliciano, E.; Gygax, J. D.; Kelley, R. L.; Li, M.; Mattson, B. J.; Mott, D. B.; Porter, F. S.; Stahle, C. M.; Szymkowiak, A. E.; Tralshawala, N.

    2000-04-01

    Superconducting bilayers made of thin films of molybdenum and gold show promise as robust transition-edge sensor (TES) thermometers for calorimeters. We present our first X-ray results from experiments with Mo/Au TES calorimeters on silicon-nitride membranes. These results include analysis of the signal pulse shape and noise as functions of the bias point, which is varied through changing the bias voltage for operation at different places within the superconducting transition and changing the heat sink temperature relative to the transition temperature. Ultimately, we determined that the performance of our devices is limited by the slew rate of the SQUID amplifier used to measure the change in current, which restricts the choice of bias. The amplifier must be replaced before further device characterization and optimization can proceed.

  5. Midnight sun

    Energy Technology Data Exchange (ETDEWEB)

    Brunger, A.P.; Lambert, S.B.; Gagnon, M.P.

    1990-09-01

    Midnight Sun, the University of Waterloo's solar-electric car, was designed and built by about 30 engineering, kinesiology and physics students for the GM Sunrayce USA held in July 1990. The car measures 2 m by 4.2 m, weighs 224 kg, can collect about 1000 W of solar electricity in full sun, and had a top speed of 79 km/h. The race took 11 days to cover the 1644 miles from the Epcot Center in Lake Buena Vista, Florida to the GM Technical Center in Warren, Michigan. Thirty-two cars, powered only by solar energy, competed in this race. Midnight Sun showed its potential during the race qualifying runs by completing the required qualifying course with the 12th fastest time of 52.83 seconds, and the 6th fastest trap speed of 63 km/h. During the Sunrayce, Midnight Sun came in second on day 1 of the race, tenth on day 6, and eighth on day 7, and was one of only 17 solar cars that were able to make it up the toughest hill in the race on day 8. The most serious problems encountered by the car were a weak rear suspension, power losses, and failure of bypass diodes in the photovoltaic array. Midnight Sun was in 17th place overall at the end of day 9. At about 11:00 am on day 10 in Ohio, the Waterloo car was moving at 60 km/h when it was bumped off the road by an out of control pickup truck. The solar car driver was not hurt. Despite the difficulties, the next day Midnight Sun was repaired and driven across the finish line at the ceremonial finish. After receiving time penalties for not completing the last day and a half of the race, Midnight Sun was awarded 24th place with an official cumulative time of 114 h 37 min 15 s. 4 figs., 4 tabs.

  6. Developments in Time-Division Multiplexing of X-ray Transition-Edge Sensors

    Science.gov (United States)

    Doriese, W. B.; Morgan, K. M.; Bennett, D. A.; Denison, E. V.; Fitzgerald, C. P.; Fowler, J. W.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Irwin, K. D.; Joe, Y. I.; Mates, J. A. B.; O'Neil, G. C.; Reintsema, C. D.; Robbins, N. O.; Schmidt, D. R.; Swetz, D. S.; Tatsuno, H.; Vale, L. R.; Ullom, J. N.

    2016-07-01

    Time-division multiplexing (TDM) is a mature scheme for the readout of arrays of transition-edge sensors (TESs). TDM is based on superconducting-quantum-interference-device (SQUID) current amplifiers. Multiple spectrometers based on gamma-ray and X-ray microcalorimeters have been operated with TDM readout, each at the scale of 200 sensors per spectrometer, as have several astronomical cameras with thousands of sub-mm or microwave bolometers. Here we present the details of two different versions of our TDM system designed to read out X-ray TESs. The first has been field-deployed in two 160-sensor (8 columns × 20 rows) spectrometers and four 240-sensor (8 columns × 30 rows) spectrometers. It has a three-SQUID-stage architecture, switches rows every 320 ns, and has total readout noise of 0.41 μ Φ 0 / surd Hz. The second, which is presently under development, has a two-SQUID-stage architecture, switches rows every 160 ns, and has total readout noise of 0.19 μ Φ 0 / surd Hz. Both quoted noise values are non-multiplexed and referred to the first-stage SQUID. In a demonstration of this new architecture, a multiplexed 1-column × 32-row array of NIST TESs achieved average energy resolution of 2.55± 0.01 eV at 6 keV.

  7. Little Sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  8. Little sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  9. Quasiparticle Transport in Thick Aluminum Films Coupled to Tungsten Transition Edge Sensors

    Science.gov (United States)

    Yen, J. J.; Kreikebaum, J. M.; Young, B. A.; Cabrera, B.; Moffatt, R.; Redl, P.; Shank, B.; Brink, P. L.; Cherry, M.; Tomada, A.

    2016-07-01

    We have fabricated and characterized test devices of a new geometry for cryogenic dark matter search superconducting sensors. The modified design uses the same photolithography masks used to fabricate earlier-generation devices, but with the Al and W films deposited in reverse order. This inverted film geometry (Al over W instead of our conventional W over Al) offers a simplified and robust way to dramatically increase the thickness of Al energy-collecting fins coupled to thin W-TESs—tungsten-transition edge sensors. Data are presented from experiments with inverted geometry test devices exposed to X-rays from a NaCl fluorescence source. The results are compared to data obtained with similar devices fabricated in the standard, non-inverted geometry.

  10. Nanosecond-scale timing jitter in transition edge sensors at telecom and visible wavelengths

    CERN Document Server

    Lamas-Linares, Antia; Tomlin, Nathan A; Gerrits, Thomas; Lita, Adriana E; Beyer, Joern; Mirin, Richard P; Nam, Sae Woo

    2013-01-01

    Transition edge sensors (TES) have the highest reported efficiencies (>98%) for detection of single photons in the visible and near infrared. Experiments in quantum information and foundations of physics that rely critically on this efficiency have started incorporating these detectors into con- ventional quantum optics setups. However, their range of applicability has been hindered by slow operation both in recovery time and timing jitter. We show here how a conventional tungsten-TES can be operated with jitter times of < 4 ns, well within the timing resolution necessary for MHz clocking of experiments, and providing an important practical simplification for experiments that rely on the simultaneous closing of both efficiency and locality loopholes.

  11. Characterization and modeling of transition edge sensors for high resolution X-ray calorimeter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Saab, T. E-mail: tsaab@milkyway.gsfc.nasa.gov; Apodacas, E.; Bandler, S.R.; Boyce, K.; Chervenak, J.; Figueroa-Feliciano, E.; Finkbeiner, F.; Hammock, C.; Kelley, R.; Lindeman, M.; Porter, F.S.; Stahle, C.K

    2004-03-11

    Characterizing and understanding, in detail, the behavior of a Transition Edge Sensor (TES) is required for achieving an energy resolution of 2 eV at 6 keV desired for future X-ray observatory missions. This paper will report on a suite of measurements (e.g. impedance and I-V among others) and simulations that were developed to extract a comprehensive set of TES parameters such as heat capacity, thermal conductivity, and R(T,I), {alpha}(T,I), and {beta}{sub i}(T,I) surfaces. These parameters allow for the study of the TES calorimeter behavior at and beyond the small signal regime.

  12. Percolation model of excess electrical noise in transition-edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lindeman, M.A. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)]. E-mail: lindeman@wisp.physics.wisc.edu; Anderson, M.B. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Bandler, S.R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bilgri, N. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Chervenak, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gwynne Crowder, S. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Fallows, S. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Figueroa-Feliciano, E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finkbeiner, F. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Iyomoto, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lai, T. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Man, J. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); McCammon, D. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Nelms, K.L. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Porter, F.S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Rocks, L.E. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Saab, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sadleir, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Vidugiris, G. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2006-04-15

    We present a geometrical model to describe excess electrical noise in transition-edge sensors (TESs). In this model, a network of fluctuating resistors represents the complex dynamics inside a TES. The fluctuations can cause several resistors in series to become superconducting. Such events short out part of the TES and generate noise because much of the current percolates through low resistance paths. The model predicts that excess white noise increases with decreasing TES bias resistance (R/R{sub N}) and that perpendicular zebra stripes reduce noise and alpha of the TES by reducing percolation.

  13. Fabrication of transition edge sensor X-ray microcalorimeters for Constellation-X

    Energy Technology Data Exchange (ETDEWEB)

    Chervenak, J.A. E-mail: james.chervenak@nasa.gov; Finkbeiner, F.M.; Stevenson, T.R.; Talley, D.J.; Brekosky, R.P.; Bandler, S.R.; Figueroa-Feliciano, E.; Lindeman, M.A.; Kelley, R.L.; Saab, T.; Stahle, C.K

    2004-03-11

    NASA's Constellation-X (Con-X) mission is a driver for advancing low-temperature detector technologies, requiring 1000-pixel two-dimensional arrays with >95% filling fraction and quantum efficiency at 6 keV and better than 4 eV energy resolution for 1-10 keV photons. We describe a robust transition edge sensor fabrication process that can produce detector arrays with integrated absorbers approaching the specifications of Con-X. We address issues such as the methods of superconducting bilayer deposition, detector geometry definition, and absorber interface.

  14. Fabrication of Microstripline Wiring for Large Format Transition Edge Sensor Arrays

    Science.gov (United States)

    Chervenak, James A.; Adams, J. M.; Bailey, C. N.; Bandler, S.; Brekosky, R. P.; Eckart, M. E.; Erwin, A. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Sadlier, J. E.; Smith, S. J.

    2012-01-01

    We have developed a process to integrate microstripline wiring with transition edge sensors (TES). The process includes additional layers for metal-etch stop and dielectric adhesion to enable recovery of parameters achieved in non-microstrip pixel designs. We report on device parameters in close-packed TES arrays achieved with the microstrip process including R(sub n), G, and T(sub c) uniformity. Further, we investigate limits of this method of producing high-density, microstrip wiring including critical current to determine the ultimate scalability of TES arrays with two layers of wiring.

  15. Development of Kilo-Pixel Arrays of Transition-Edge Sensors for X-Ray Spectroscopy

    Science.gov (United States)

    Adams, J. S.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kelly, D. P.; Kilbourne, C. A.; Leutenegger, M. A.; Porst, J.-P.; Porter, F. S.; Ray, C. A.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Irwin, K. D.; Reintsema, C. D.; Smith, D. R.; Swetz, D. S.

    2012-01-01

    We are developing kilo-pixel arrays of transition-edge sensor (TES) microcalorimeters for future X-ray astronomy observatories or for use in laboratory astrophysics applications. For example, Athena/XMS (currently under study by the european space agency) would require a close-packed 32x32 pixel array on a 250-micron pitch with pixel/second. We present characterization of 32x32 arrays. These detectors will be readout using state of the art SQUID based time-domain multiplexing (TDM). We will also present the latest results in integrating these detectors and the TDM readout technology into a 16 row x N column field-able instrument.

  16. Sun Proof

    Centers for Disease Control (CDC) Podcasts

    2012-10-23

    In this podcast for kids, the Kidtastics talk about the harmful effects of the sun and how to protect yourself from it.  Created: 10/23/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/23/2012.

  17. Fabrication of superconducting transition edge sensor based on Mo and Au bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Minhee [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)]. E-mail: yunmh@engr.pitt.edu; Bock, James [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Keynon, Mattew [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kuo, C.-L. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Leduc, Henry [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Turner, Anthony [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kim, Moon J. [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75083-0688 (United States)

    2006-04-15

    We report fabricated antenna-coupled superconducting transition edge sensor (TES) for millimeter-wave polarimetry. Superconducting microwave components for an antenna-coupled focal plane will be described in this work. We use low-loss Nb/SiO/Nb transmission line as base materials as a start, although changes in the dielectric may be possible to reduce loss further. Additionally, we have fabricated single- and double-element antennas, filters and detectors. We use TES bilayers consisting of Mo/Au thin films and Nb electrical contacts on a low-stress Si{sub 3}N{sub 4} membrane. In this work, we report transition temperature as a function of Mo thicknesses and Au film composition.

  18. Optimization of Transition Edge Sensor Arrays for Cosmic Microwave Background Observations With the South Pole Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Junjia; Ade, P. A. R.; Anderson, A. J.; Avva, J.; Ahmed, Z.; Arnold, K.; Austermann, J. E.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Byrum, K.; Carlstrom, J. E.; Carter, F. W.; Chang, C. L.; Cho, H. M.; Cliche, J. F.; Cukierman, A.; Czaplewski, D.; Divan, R.; de Haan, T.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Gilbert, A.; Gannon, R.; Guyser, R.; Halverson, N. W.; Harrington, N. L.; Hattori, K.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Hubmayr, J.; Huang, N.; Irwin, K. D.; Jeong, O.; Khaire, T.; Kubik, D.; Kuo, C. L.; Lee, A. T.; Leitch, E. M.; Meyer, S. S.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Shariff, J. A.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J.; Stan, L.; Stark, A. A.; Story, K.; Suzuki, A.; Tang, Q. Y.; Thakur, R. B.; Thompson, K. L.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Wu, W. L. K.; Yefremenko, V.; Yoon, K. W.

    2017-06-01

    In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South PoleTelescope. The camera, which contains similar to 16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs.

  19. The Role of Proximity Effects in Transition-Edge Sensor Design and Performance

    Science.gov (United States)

    Smith, Stephen J.

    2012-01-01

    Transition-edge sensor (TES) microcalorimeters and bolometers are under development by numerous groups worldwide for a variety of applications involving the measurement of particle and photon radiation. Recent experimental and theoretical progress has led to the realization that the fundamental physics of some TES systems involves the longitudinal proximity effect between the electrical bias contacts and the TES. As such, these devices are described as SS'S (or SN'S) weak-links exhibiting Fraunhofer-like magnetic field dependence, and exponential temperature dependence, of the critical current. These discoveries, for the first time, provide a realistic theoretical framework for predicting the resistive transition as a function of temperature, current and magnetic field. In this contribution, we review the latest theoretical and experimental results and investigate how proximity effects play an important role in determining the resistive transition characteristics, which ultimately determines the dynamic range and energy resolution of TES detectors. We investigate how these effects could be utilized in device design to engineer desired transition characteristics for a given application.

  20. Implications of Weak Link Effects on Thermal Characteristics of Transition-Edge Sensors

    Science.gov (United States)

    Bailey, C. N.; Adams, J. S.; Bandler, S. R.; Brekosky, R. P.; Chevenak, J. A.; Eckart, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kally, D. P.; Kilbourne, C. A.; Porter, F. S.; Sadleir, J. E.; Smith, S. J.

    2012-01-01

    Weak link behavior in transition-edge sensor (TES) microcalorimeters creates the need for a more careful characterization of a device's thermal characteristics through its transition. This is particularly true for small TESs where a small change in the bias current results in large changes in effective transition temperature. To correctly interpret measurements, especially complex impedance, it is crucial to know the temperature-dependent thermal conductance, G(T), and heat capacity, C(T), at each point through the transition. We present data illustrating these effects and discuss how we overcome the challenges that are present in accurately determining G and T from I-V curves. We also show how these weak link effects vary wi.th TES size. Additionally, we use this improVed understanding of G(T) to determine that, for these TES microcalorimeters. Kaptiza boundary resistance dominates the G of devices with absorbers while the electron-phonon coupling also needs to be considered when determining G for devices without absorbers

  1. Implications of Weak Link Effects on Thermal Characteristics of Transition-Edge Sensors

    Science.gov (United States)

    Bailey, C. N.; Adams, J. S.; Bandler, S. R.; Brekosky, R. P.; Chevenak, J. A.; Eckart, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kally, D. P.; Kilbourne, C. A.; hide

    2012-01-01

    Weak link behavior in transition-edge sensor (TES) microcalorimeters creates the need for a more careful characterization of a device's thermal characteristics through its transition. This is particularly true for small TESs where a small change in the bias current results in large changes in effective transition temperature. To correctly interpret measurements, especially complex impedance, it is crucial to know the temperature-dependent thermal conductance, G(T), and heat capacity, C(T), at each point through the transition. We present data illustrating these effects and discuss how we overcome the challenges that are present in accurately determining G and T from I-V curves. We also show how these weak link effects vary wi.th TES size. Additionally, we use this improVed understanding of G(T) to determine that, for these TES microcalorimeters. Kaptiza boundary resistance dominates the G of devices with absorbers while the electron-phonon coupling also needs to be considered when determining G for devices without absorbers

  2. Development of Position-sensitive Transition-edge Sensor X-ray Detectors

    Science.gov (United States)

    Smith, S. J.; Bandler, S. R.; Brekosky, R. P.; Brown, A.-D.; Chervenak, J. A.; Eckard, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. s.; Sad (eor. K/ E/); Figueroa-Feliciano, E.

    2008-01-01

    We report on the development of position-sensitive transition-edge sensors (PoST's) for future x-ray astronomy missions such as the International X-ray Observatory (IXO), currently under study by NASA and ESA. PoST's consist of multiple absorbers each with a different thermal coupling to one or more transition-edge sensor (TES). This differential thermal coupling between absorbers and TES's results in different characteristic pulse shapes and allows position discrimination between the different pixels. The development of PoST's is motivated by a desire to achieve maximum focal-plane area with the least number of readout channels and as such. PoST's are ideally suited to provide a focal-plane extension to the Constellation-X microcalorimeter array. We report the first experimental results of our latest one and two channel PoST's, which utilize fast thermalizing electroplated Au/Bi absorbers coupled to low noise Mo/Au TES's - a technology already successfully implemented in our arrays of single pixel TES's. We demonstrate 6 eV energy resolution coupled with spatial sensitivity in the keV energy range. We also report on the development of signal processing algorithms to optimize energy and position sensitivity of our detectors.

  3. Preferred gait and walk-run transition speeds in ostriches measured using GPS-IMU sensors.

    Science.gov (United States)

    Daley, Monica A; Channon, Anthony J; Nolan, Grant S; Hall, Jade

    2016-10-15

    The ostrich (Struthio camelus) is widely appreciated as a fast and agile bipedal athlete, and is a useful comparative bipedal model for human locomotion. Here, we used GPS-IMU sensors to measure naturally selected gait dynamics of ostriches roaming freely over a wide range of speeds in an open field and developed a quantitative method for distinguishing walking and running using accelerometry. We compared freely selected gait-speed distributions with previous laboratory measures of gait dynamics and energetics. We also measured the walk-run and run-walk transition speeds and compared them with those reported for humans. We found that ostriches prefer to walk remarkably slowly, with a narrow walking speed distribution consistent with minimizing cost of transport (CoT) according to a rigid-legged walking model. The dimensionless speeds of the walk-run and run-walk transitions are slower than those observed in humans. Unlike humans, ostriches transition to a run well below the mechanical limit necessitating an aerial phase, as predicted by a compass-gait walking model. When running, ostriches use a broad speed distribution, consistent with previous observations that ostriches are relatively economical runners and have a flat curve for CoT against speed. In contrast, horses exhibit U-shaped curves for CoT against speed, with a narrow speed range within each gait for minimizing CoT. Overall, the gait dynamics of ostriches moving freely over natural terrain are consistent with previous lab-based measures of locomotion. Nonetheless, ostriches, like humans, exhibit a gait-transition hysteresis that is not explained by steady-state locomotor dynamics and energetics. Further study is required to understand the dynamics of gait transitions.

  4. Irreversible phase transitions in doped metal oxides as temperature sensors in explosions

    Science.gov (United States)

    Eilers, Hergen; Gunawidjaja, Ray; Myint, Thandar; Lightstone, James

    2011-06-01

    The temperature of post-detonation fireballs produced by advanced energetic formulations is commonly determined using optical methods such as pyrometry and spectral line fitting. These methods provide an average temperature mostly from the surface of the fireball. However, for many applications the ability to probe the internal temperature and temperature gradients within the fireball is highly desirable. One method that has shown promise is seeding micron to nano-sized temperature sensors into the fireball which can be collected and analyzed post-detonation. In this work, disordered Eu3+-doped nanoparticles were subjected to various heat treatments, incl. furnace, T-Jump, pulsed laser, and explosive heating. This treatment leads to irreversible phase transitions which are monitored by the Eu dopants. Optical signatures such as the ratio of electric and magnetic dipole transition intensities, energy level splitting, FWHM, etc. are evaluated to monitor the phase transitions. Also, the kinetics of particle growth is evaluated as an indicator for the time-dependence of the heating process. The information is used to establish a correlation with the temperature profile. Temperature profiles collected from a series of lab-based tests and small-scale detonations of an aluminized explosive will be presented. This work was supported by the Defense Threat Reduction Agency.

  5. Characterization of a Transition-Edge Sensor for the ALPS II Experiment

    CERN Document Server

    Bastidon, Noemie; Lindner, Axel

    2015-01-01

    The ALPS II experiment, Any Light Particle Search II at DESY in Hamburg, will look for light (m< 10-4 eV) new fundamental bosons (e.g., axion-like particles, hidden photons and other WISPs) in the next years by the mean of a light-shining-through-the-wall setup. The ALPS II photosensor is a Transition-Edge Sensor (TES) optimized for lambda = 1064 nm photons. The detector is routinely operated at 80 mK, allowing single infrared photon detections as well as non-dispersive spectroscopy with very low background rates. The demonstrated quantum efficiency for such TES is up to 95% at lambda =1064 nm. For 1064 nm photons, the measured background rate is < 10-2 sec-1 and the intrinsic dark count rate in a dark environment was found to be of 1,0.10-4 sec-1. Latest characterization results are discussed.

  6. Readout of two-kilopixel transition-edge sensor arrays for Advanced ACTPol

    CERN Document Server

    Henderson, Shawn W; Amiri, Mandana; Austermann, Jason; Beall, James A; Chaudhuri, Saptarshi; Cho, Hsiao-Mei; Choi, Steve K; Cothard, Nicholas F; Crowley, Kevin T; Duff, Shannon M; Fitzgerald, Colin P; Gallardo, Patricio A; Halpern, Mark; Hasselfield, Matthew; Hilton, Gene; Ho, Shuay-Pwu Patty; Hubmayr, Johannes; Irwin, Kent D; Koopman, Brian J; Li, Dale; Li, Yaqiong; McMahon, Jeff; Nati, Federico; Niemack, Michael D; Reintsema, Carl D; Salatino, Maria; Schillaci, Alessandro; Schmitt, Benjamin L; Simon, Sara M; Staggs, Suzanne T; Vavagiakis, Eve M; Ward, Jonathan T

    2016-01-01

    Advanced ACTPol is an instrument upgrade for the six-meter Atacama Cosmology Telescope (ACT) designed to measure the cosmic microwave background (CMB) temperature and polarization with arcminute-scale angular resolution. To achieve its science goals, Advanced ACTPol utilizes a larger readout multiplexing factor than any previous CMB experiment to measure detector arrays with approximately two thousand transition-edge sensor (TES) bolometers in each 150 mm detector wafer. We present the implementation and testing of the Advanced ACTPol time-division multiplexing readout architecture with a 64-row multiplexing factor. This includes testing of individual multichroic detector pixels and superconducting quantum interference device (SQUID) multiplexing chips as well as testing and optimizing of the integrated readout electronics. In particular, we describe the new automated multiplexing SQUID tuning procedure developed to select and optimize the thousands of SQUID parameters required to readout each Advanced ACTPol...

  7. Device modeling of superconductor transition edge sensors based on the two-fluid theory

    CERN Document Server

    Wang, Tian-Shun; Zhu, Qing-Feng; Wang, Jun-Xian; Li, Tie-Fu; Liu, Jian-She; Chen, Wei; Zhou, Xingxiang

    2012-01-01

    In order to support the design and study of sophisticated large scale transition edge sensor (TES) circuits, we use basic SPICE elements to develop device models for TESs based on the superfluid-normal fluid theory. In contrast to previous studies, our device model is not limited to small signal simulation, and it relies only on device parameters that have clear physical meaning and can be easily measured. We integrate the device models in design kits based on powerful EDA tools such as CADENCE and OrCAD, and use them for versatile simulations of TES circuits. Comparing our simulation results with published experimental data, we find good agreement which suggests that device models based on the two-fluid theory can be used to predict the behavior of TES circuits reliably and hence they are valuable for assisting the design of sophisticated TES circuits.

  8. Fabrication of Transition Edge Sensor Microcalorimeters for X-Ray Focal Planes

    Science.gov (United States)

    Chervenak, James A.; Adams, Joseph S.; Audley, Heather; Bandler, Simon R.; Betancourt-Martinez, Gabriele; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline; Lee, Sang Jun; Mateo, Jennette; Sadleir, John E.; Smith, Stephen J.; Wassell, Edward; Yoon, Wonsik

    2015-01-01

    Requirements for focal planes for x-ray astrophysics vary widely depending on the needs of the science application such as photon count rate, energy band, resolving power, and angular resolution. Transition edge sensor x-ray calorimeters can encounter limitations when optimized for these specific applications. Balancing specifications leads to choices in, for example, pixel size, thermal sinking arrangement, and absorber thickness and material. For the broadest specifications, instruments can benefit from multiple pixel types in the same array or focal plane. Here we describe a variety of focal plane architectures that anticipate science requirements of x-ray instruments for heliophysics and astrophysics. We describe the fabrication procedures that enable each array and explore limitations for the specifications of such arrays, including arrays with multiple pixel types on the same array.

  9. An investigation of excess noise in transition-edge sensors on a solid silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, S.G. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)]. E-mail: sgcrowder@wisc.edu; Lindeman, M.A. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Anderson, M.B. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Bandler, S.R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bilgri, N. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Bruijn, M.P. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, Utrecht 3584 CA (Netherlands); Chervenak, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Figueroa-Feliciano, E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finkbeiner, F. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Germeau, A. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, Utrecht 3584 CA (Netherlands); Hoevers, H.F.C. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, Utrecht 3584 CA (Netherlands); Iyomoto, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelly, R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lai, T. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Man, J. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); McCammon, D.; Nelms, K.L.; Rocks, L.; Vidugiris, G. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Porter, F.S.; Saab, T.; Sadleir, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2006-04-15

    Transition-edge sensors (TESs) exhibit two major types of excess noise above the expected and unavoidable thermodynamic fluctuation noise (TFN) to the heat sink and Johnson noise. High-resistance TESs such as those made by the Netherlands Institute for Space Research (SRON) show excess noise consistent with internal TFN (ITFN) caused by random energy transport within the TES itself while low resistance TESs show an excess voltage noise of unknown origin seemingly unrelated to temperature fluctuations. Running a high-resistance TES on a high thermal conductivity substrate should suppress ITFN and allow detection of any excess voltage noise. We tested two TESs on a solid silicon substrate fabricated by SRON of a relatively high normal state resistance of {approx}200 m{omega}. After determining a linear model of the TES response to noise for the devices, we found little excess TFN and little excess voltage noise for bias currents of up to {approx}20 {mu}A.

  10. An oxidative N-demethylase reveals PAS transition from ubiquitous sensor to enzyme.

    Science.gov (United States)

    Ortmayer, Mary; Lafite, Pierre; Menon, Binuraj R K; Tralau, Tewes; Fisher, Karl; Denkhaus, Lukas; Scrutton, Nigel S; Rigby, Stephen E J; Munro, Andrew W; Hay, Sam; Leys, David

    2016-11-24

    The universal Per-ARNT-Sim (PAS) domain functions as a signal transduction module involved in sensing diverse stimuli such as small molecules, light, redox state and gases. The highly evolvable PAS scaffold can bind a broad range of ligands, including haem, flavins and metal ions. However, although these ligands can support catalytic activity, to our knowledge no enzymatic PAS domain has been found. Here we report characterization of the first PAS enzyme: a haem-dependent oxidative N-demethylase. Unrelated to other amine oxidases, this enzyme contains haem, flavin mononucleotide, 2Fe-2S and tetrahydrofolic acid cofactors, and specifically catalyses the NADPH-dependent oxidation of dimethylamine. The structure of the α subunit reveals that it is a haem-binding PAS domain, similar in structure to PAS gas sensors. The dimethylamine substrate forms part of a highly polarized oxygen-binding site, and directly assists oxygen activation by acting as both an electron and proton donor. Our data reveal that the ubiquitous PAS domain can make the transition from sensor to enzyme, suggesting that the PAS scaffold can support the development of artificial enzymes.

  11. The Transition-Edge-Sensor Array for the Micro-X Sounding Rocket

    Science.gov (United States)

    Eckart, M. E.; Adams, J. S.; Bailey, C. N.; Bandler, S. R.; Busch, Sarah Elizabeth; Chervenak J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porst, J. P.; Porter, F. S.; Sadleir, J. E.; Smith, Stephen J.; Figueroa-Feliciano, Enectali

    2012-01-01

    The Micro-X sounding rocket program will fly a 128-element array of transition-edge-sensor microcalorimeters to enable high-resolution X-ray imaging spectroscopy of the Puppis-A supernova remnant. To match the angular resolution of the optics while maximizing the field-of-view and retaining a high energy resolution (< 4 eV at 1 keV), we have designed the pixels using 600 x 600 sq. micron Au/Bi absorbers, which overhang 140 x 140 sq. micron Mo/Au sensors. The data-rate capabilities of the rocket telemetry system require the pulse decay to be approximately 2 ms to allow a significant portion of the data to be telemetered during flight. Here we report experimental results from the flight array, including measurements of energy resolution, uniformity, and absorber thermalization. In addition, we present studies of test devices that have a variety of absorber contact geometries, as well as a variety of membrane-perforation schemes designed to slow the pulse decay time to match the telemetry requirements. Finally, we describe the reduction in pixel-to-pixel crosstalk afforded by an angle-evaporated Cu backside heatsinking layer, which provides Cu coverage on the four sidewalls of the silicon wells beneath each pixel.

  12. Non-linear effects in transition edge sensors for X-ray detection

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)]. E-mail: sbandler@milkyway.gsfc.nasa.gov; Figueroa-Feliciano, E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Iyomoto, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R.L. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Murphy, K.D. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Porter, F.S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Saab, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sadleir, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2006-04-15

    In a microcalorimeter that uses a transition-edge sensor to detect energy depositions, the small signal energy resolution improves with decreasing heat capacity. This improvement remains true up to the point where non-linear and saturation effects become significant. This happens when the energy deposition causes a significant change in the sensor resistance. Not only does the signal size become a non-linear function of the energy deposited, but also the noise becomes non-stationary over the duration of the pulse. Algorithms have been developed that can calculate the optimal performance given this non-linear behavior that typically requires significant processing and calibration work-both of which are impractical for space missions. We have investigated the relative importance of the various non-linear effects, with the hope that a computationally simple transformation can overcome the largest of the non-linear and non-stationary effects, producing a highly linear 'gain' for pulse-height versus energy, and close to the best energy resolution at all energies when using a Wiener filter.

  13. Fabrication and Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

    Science.gov (United States)

    Chervenak, James A.; Adams, James S.; Bandler, Simon R.; Busch, Sara E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, Jan-Patrick; Porter, Frederick S.; Ray, C.; Sadleir, John E.; Smith, S. J.; Wassell, Edward J.

    2012-01-01

    We have produced a variety of superconducting transition edge sensor array designs for microcalorimetric detection of x-rays. Designs include kilopixel scale arrays of relatively small sensors (75 micron pitch) atop a thick metal heatsinking layer as well as arrays of membrane-isolated devices on 250 micron pitch and smaller arrays of devices up to 600 micron pitch. We discuss the fabrication techniques used for each type of array focusing on unique aspects where processes vary to achieve the particular designs and required device parameters. For example, we evaluate various material combinations in the production of the thick metal heatsinking, including superconducting and normal metal adhesion layers. We also evaluate the impact of added heatsinking on the membrane isolated devices as it relates to basic device parameters. Arrays can be characterized with a time division SQUID multiplexer such that greater than 10 devices from an array can be measured in the same cooldown. Device parameters can be measured simultaneously so that environmental events such as thermal drifts or changes in magnetic fields can be controlled. For some designs, we will evaluate the uniformity of parameters impacting the intrinsic performance of the microcalorimeters under bias in these arrays and assess the level of thermal crosstalk.

  14. Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Eckart, M. E.; Smith, Adams; Bailey, C. N.; Bandler, S. R.; Chevenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; hide

    2012-01-01

    We are developing small pitch transition-edge sensor (TES) X-ray detectors optimized for solar astronomy. These devices are fabricated on thick Si substrates with embedded Cu heat-sink layer. We use 35 x 35 square micrometers Mo/Au TESs with 4.5 micrometer thick Au absorbers. We have tested devices with different geometric absorber stem contact areas with the TES and surrounding substrate area. This allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between thc stem contact area and a broadening in the spectral line shape indicative of athermal phonon loss. When the contact area is minimized we have obtained exceptional broadband spectral resolution of 1.28 plus or minus 0.03 eV at an energy of 1.5 keV, 1.58 plus or minus 0.07 eV at 5.9 keV and 1.96 plus or minus 0.08 eV at 8 keV. The linearity in the measured gain scale is understood in the context of the longitudinal proximity effect from the electrical bias leads resulting in transition characteristics that are strongly dependent upon TES size.

  15. Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Eckart, M. E.; Smith, Adams; Bailey, C. N.; Bandler, S. R.; Chevenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Sadleir, J. E.

    2012-01-01

    We are developing small pitch transition-edge sensor (TES) X-ray detectors optimized for solar astronomy. These devices are fabricated on thick Si substrates with embedded Cu heat-sink layer. We use 35 x 35 square micrometers Mo/Au TESs with 4.5 micrometer thick Au absorbers. We have tested devices with different geometric absorber stem contact areas with the TES and surrounding substrate area. This allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between thc stem contact area and a broadening in the spectral line shape indicative of athermal phonon loss. When the contact area is minimized we have obtained exceptional broadband spectral resolution of 1.28 plus or minus 0.03 eV at an energy of 1.5 keV, 1.58 plus or minus 0.07 eV at 5.9 keV and 1.96 plus or minus 0.08 eV at 8 keV. The linearity in the measured gain scale is understood in the context of the longitudinal proximity effect from the electrical bias leads resulting in transition characteristics that are strongly dependent upon TES size.

  16. Experimental study for the detection of the laminar/turbulent aerodynamic transition on a wing aircraft, using fiber optic sensors

    Science.gov (United States)

    Molin, S.; Dolfi, D.; Doisy, M.; Seraudie, A.; Arnal, D.; Coustols, E.; Mandle, J.

    2010-09-01

    We demonstrate the feasibility of detection of the nature (laminar/turbulent/transitional) of the aerodynamic boundary layer of a profile of a wing aircraft model, using a Distributed FeedBack (DFB) Fiber Laser as optical fiber sensor. Signals to be measured are pressure variations : ΔP~1Pa at few 100Hz in the laminar region and ΔP~10Pa at few kHz in the turbulent region. Intermittent regime occurring in-between these two regions (transition) is characterized by turbulent bursts in laminar flow. Relevant pressure variations have been obtained in a low-speed research-type wind tunnel of ONERA Centre of Toulouse. In order to validate the measurements, a "classical" hot film sensor, the application and use of which have been formerly developed and validated by ONERA, has been placed at the neighborhood of the fiber sensor. The hot film allows measurement of the boundary layer wall shear stress whose characteristics are a well known signature of the boundary layer nature (laminar, intermittent or turbulent) [1]. In the three regimes, signals from the fiber sensor and the hot film sensor are strongly correlated, which allows us to conclude that a DFB fiber laser sensor is a good candidate for detecting the boundary layer nature, and thus for future integration in an aircraft wing. The work presented here has been realized within the framework of "Clean Sky", a Joint Technology Initiative of the European Union.

  17. On the Design of a Wearable Multi-sensor System for Recognizing Motion Modes and Sit-to-stand Transition

    Directory of Open Access Journals (Sweden)

    Enhao Zheng

    2014-02-01

    Full Text Available Locomotion mode recognition is one of the key aspects of control of intelligent prostheses. This paper presents a wireless wearable multi-sensor system for locomotion mode recognition. The sensor suit of the system includes three inertial measurement units (IMUs and eight force sensors. The system was built to measure both kinematic (tilt angles and dynamic (ground contact forces signals of human gaits. To evaluate the recognition performance of the system, seven motion modes and sit-to-stand transition were monitored. With a linear discriminant analysis (LDA classifier, the proposed system can accurately classify the current states. The overall motion mode recognition accuracy was 99.9% during the stance phase and 98.5% during the swing phase. For sit-to-stand transition recognition, the average accuracy was 99.9%. These promising results show the potential of the designed system for the control of intelligent prostheses.

  18. On the Design of a Wearable Multi-sensor System for Recognizing Motion Modes and Sit-to-stand Transition

    Directory of Open Access Journals (Sweden)

    Enhao Zheng

    2014-02-01

    Full Text Available Locomotion mode recognition is one of the key aspects of control of intelligent prostheses. This paper presents a wireless wearable multi-sensor system for locomotion mode recognition. The sensor suit of the system includes three inertial measurement units (IMUs and eight force sensors. The system was built to measure both kinematic (tilt angles and dynamic (ground contact forces signals of human gaits. To evaluate the recognition performance of the system, seven motion modes and sit-to-stand transition were monitored. With a linear discriminant analysis (LDA classifier, the proposed system can accurately classify the current states. The overall motion mode recognition accuracy was 99.9% during the stance phase and 98.5% during the swing phase. For sit-to-stand transition recognition, the average accuracy was 99.9%. These promising results show the potential of the designed system for the control of intelligent prostheses.

  19. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  20. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  1. Gamma-Ray Transition-Edge Sensor Microcalorimeters on Solid Substrates

    Science.gov (United States)

    Iyomoto, Naoko; Kawakami, Hisao; Maehata, Keisuke; Yoshimine, Ikumi; Shuto, Yuki; Nagayoshi, Kenichiro; Mitsuda, Kazuhisa; Ezaki, Shohei; Takano, Akira; Yoshimoto, Shota; Ishibashi, Kenji

    2016-07-01

    We develop transition-edge-sensor microcalorimeters for gamma-ray spectroscopy. To develop mechanically robust detectors, we fabricated devices with no membrane structure. We report results of three such devices, two with a Bi-absorber and the other with a Sn-absorber. The thickness and volume of each absorber are 1 mm and 0.5-0.6 mm3. We cooled the detectors and irradiated each with gamma rays from a Cs-137 source and observed two types of pulses: slow-rise and fast-rise. The slow-rise pulses are signals from gamma rays absorbed or Compton scattered in the absorbers and the fast-rise pulses are signals resulting from Compton scattering in the Si substrate. We selected the slow pulses to obtain energy spectra. The energy resolutions of the 662-keV photo peak for the Bi-absorber and Sn-absorber devices are, respectively, 4.1 and 7.5 keV, whereas their baseline energy resolutions are 3.2 and 2.6 keV. The degradation in energy resolution is mainly because of the fluctuation of bath temperature. The baseline energy resolutions are more than an order of magnitude worse than the design values. The poor resolution probably arises because of thermal noise from Compton events on the Si substrate.

  2. Emerging 0D Transition-Metal Dichalcogenides for Sensors, Biomedicine, and Clean Energy.

    Science.gov (United States)

    Li, Bang Lin; Setyawati, Magdiel Inggrid; Zou, Hao Lin; Dong, Jiang Xue; Luo, Hong Qun; Li, Nian Bing; Leong, David Tai

    2017-08-01

    Following research on two-dimensional (2D) transition metal dichalcogenides (TMDs), zero-dimensional (0D) TMDs nanostructures have also garnered some attention due to their unique properties; exploitable for new applications. The 0D TMDs nanostructures stand distinct from their larger 2D TMDs cousins in terms of their general structure and properties. 0D TMDs possess higher bandgaps, ultra-small sizes, high surface-to-volume ratios with more active edge sites per unit mass. So far, reported 0D TMDs can be mainly classified as quantum dots, nanodots, nanoparticles, and small nanoflakes. All exhibited diverse applications in various fields due to their unique and excellent properties. Of significance, through exploiting inherent characteristics of 0D TMDs materials, enhanced catalytic, biomedical, and photoluminescence applications can be realized through this exciting sub-class of TMDs. Herein, we comprehensively review the properties and synthesis methods of 0D TMDs nanostructures and focus on their potential applications in sensor, biomedicine, and energy fields. This article aims to educate potential adopters of these excitingly new nanomaterials as well as to inspire and promote the development of more impactful applications. Especially in this rapidly evolving field, this review may be a good resource of critical insights and in-depth comparisons between the 0D and 2D TMDs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Few-photon color imaging using energy-dispersive superconducting transition-edge sensor spectrometry

    Science.gov (United States)

    Niwa, Kazuki; Numata, Takayuki; Hattori, Kaori; Fukuda, Daiji

    2017-01-01

    Highly sensitive spectral imaging is increasingly being demanded in bioanalysis research and industry to obtain the maximum information possible from molecules of different colors. We introduce an application of the superconducting transition-edge sensor (TES) technique to highly sensitive spectral imaging. A TES is an energy-dispersive photodetector that can distinguish the wavelength of each incident photon. Its effective spectral range is from the visible to the infrared (IR), up to 2800 nm, which is beyond the capabilities of other photodetectors. TES was employed in this study in a fiber-coupled optical scanning microscopy system, and a test sample of a three-color ink pattern was observed. A red–green–blue (RGB) image and a near-IR image were successfully obtained in the few-incident-photon regime, whereas only a black and white image could be obtained using a photomultiplier tube. Spectral data were also obtained from a selected focal area out of the entire image. The results of this study show that TES is feasible for use as an energy-dispersive photon-counting detector in spectral imaging applications. PMID:28374801

  4. Code-division multiplexing of superconducting transition-edge sensor arrays

    Science.gov (United States)

    Irwin, K. D.; Niemack, M. D.; Beyer, J.; Cho, H. M.; Doriese, W. B.; Hilton, G. C.; Reintsema, C. D.; Schmidt, D. R.; Ullom, J. N.; Vale, L. R.

    2010-03-01

    Multiplexed superconducting quantum interference device (SQUID) amplifiers have recently enabled the deployment of kilopixel arrays of superconducting transition-edge sensor (TES) detectors on a variety of receivers for astrophysics. Existing multiplexing techniques for TES arrays, however, have constraints due to aliasing of SQUID noise, the size of the required filtering elements, or the complexity of the room-temperature electronics that make it difficult to scale to much larger arrays. We have developed a Walsh code-division SQUID multiplexer that has the potential to enable the multiplexing of larger arrays or pixels with faster thermal response times. The multiplexer uses superconducting switches to modulate the polarity of coupling between N individual TES detectors and a single output SQUID channel. The polarities of the detector signals are switched in the pattern of an N × N Walsh matrix, so a frame composed of N orthogonal samples can be used to reconstruct the detector signals without degradation. We present an analysis of the circuit architecture and preliminary results.

  5. Few-photon color imaging using energy-dispersive superconducting transition-edge sensor spectrometry.

    Science.gov (United States)

    Niwa, Kazuki; Numata, Takayuki; Hattori, Kaori; Fukuda, Daiji

    2017-04-04

    Highly sensitive spectral imaging is increasingly being demanded in bioanalysis research and industry to obtain the maximum information possible from molecules of different colors. We introduce an application of the superconducting transition-edge sensor (TES) technique to highly sensitive spectral imaging. A TES is an energy-dispersive photodetector that can distinguish the wavelength of each incident photon. Its effective spectral range is from the visible to the infrared (IR), up to 2800 nm, which is beyond the capabilities of other photodetectors. TES was employed in this study in a fiber-coupled optical scanning microscopy system, and a test sample of a three-color ink pattern was observed. A red-green-blue (RGB) image and a near-IR image were successfully obtained in the few-incident-photon regime, whereas only a black and white image could be obtained using a photomultiplier tube. Spectral data were also obtained from a selected focal area out of the entire image. The results of this study show that TES is feasible for use as an energy-dispersive photon-counting detector in spectral imaging applications.

  6. Multi-Absorber Transition-Edge Sensors for X-Ray Astronomy Applications

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kelly, D. P.; hide

    2012-01-01

    We are developing multi-absorber Transition-Edge Sensors (TESs) for applications in x-ray astronomy. These position-sensitive devices consist of multiple x-ray absorbers each with a different thermal coupling to a single readout TES. Heat diffusion between the absorbers and the TES gives rise to a characteristic pulse shape corresponding to each absorber element and enables position discrimination. The development of these detectors is motivated by a desire to maximize focal plane arrays with the fewest number of readout channels. In this contribution we report on the first results from devices consisting of nine) 65 X 65 sq. microns Au x-ray absorbers) 5 microns thick. These are coupled to a single 35 X 35 sq. microns Mo/Au bilayer TES. These devices have demonstrated full-width-half-maximum (FWHM) energy resolution of 2.1 eV at 1.5 keV) 2.5 eV at 5.9 keV and 3.3 eV at 8 keV. This is coupled with position discrimination from pulse shape over the same energy range. We use a finite-element model to reproduce the measured pulse shapes and investigate the detector non-linearity with energy) which impacts on the devices position sensitivity and energy resolution.

  7. Development of holmium-163 electron-capture spectroscopy with transition-edge sensors

    CERN Document Server

    Croce, M P; Mocko, V; Kunde, G J; Birnbaum, E R; Bond, E M; Engle, J W; Hoover, A S; Nortier, F M; Pollington, A D; Taylor, W A; Weisse-Bernstein, N R; Wolfsberg, L E; Hays-Wehle, J P; Schmidt, D R; Swetz, D S; Ullom, J N; Barnhart, T E; Nickles, R J

    2015-01-01

    Calorimetric decay energy spectroscopy of electron-capture-decaying isotopes is a promising method to achieve the sensitivity required for electron neutrino mass measurement. The very low total nuclear decay energy (QEC < 3 keV) and short half-life (4570 y) of 163Ho make it attractive for high-precision electron capture spectroscopy (ECS) near the kinematic endpoint, where the neutrino momentum goes to zero. In the ECS approach, an electron-capture-decaying isotope is embedded inside a microcalorimeter designed to capture and measure the energy of all the decay radiation except that of the escaping neutrino. We have developed a complete process for proton-irradiation-based isotope production, isolation, and purification of 163Ho. We have developed transition-edge sensors for this measurement and methods for incorporating 163Ho into high-resolution microcalorimeters, and have measured the electron-capture spectrum of 163Ho. We present our work in these areas and discuss the measured spectrum and its compari...

  8. The Atacama B-Mode Search: CMB Polarimetry with Transition-Edge-Sensor Bolometers

    CERN Document Server

    Essinger-Hileman, T; Beall, J A; Cho, H M; Fowler, J; Halpern, M; Hasselfield, M; Irwin, K D; Marriage, T A; Niemack, M D; Page, L; Parker, L P; Pufu, S; Staggs, S T; Stryzak, O; Visnjic, C; Yoon, K W; Zhao, Y

    2010-01-01

    The Atacama B-mode Search (ABS) experiment is a 145 GHz polarimeter designed to measure the B-mode polarization of the Cosmic Microwave Background (CMB) at large angular scales. The ABS instrument will ship to the Atacama Desert of Chile fully tested and ready to observe in 2010. ABS will image large-angular-scale CMB polarization anisotropies onto a focal plane of 240 feedhorn-coupled, transition-edge sensor (TES) polarimeters, using a cryogenic crossed-Dragone design. The ABS detectors, which are fabricated at NIST, use orthomode transducers to couple orthogonal polarizations of incoming radiation onto separate TES bolometers. The incoming radiation is modulated by an ambient-temperature half-wave plate in front of the vacuum window at an aperture stop. Preliminary detector characterization indicates that the ABS detectors can achieve a sensitivity of 300 $\\mu K \\sqrt{s}$ in the field. This paper describes the ABS optical design and detector readout scheme, including feedhorn design and performance, magneti...

  9. Absorber Materials for Transition-Edge Sensor X-ray Microcalorimeters

    Science.gov (United States)

    Brown, Ari-David; Bandler, Simon; Brekosky, Regis; Chervenak, James; Figueroa-Feliciano, Enectali; Finkbeiner, Fred; Sadleir, Jack; Iyomoto, Naoko; Kelley, Richard; Kilbourne, Caroline; Porter, F. Scott; Smith, Stephen; Saab, Tarek; Sadleir, Jac,

    2007-01-01

    Arrays of superconducting transition-edge sensors (TES) can provide high spatial and energy resolution necessary for x-ray astronomy. High quantum efficiency and uniformity of response can be achieved with a suitable absorber material, in which absorber x-ray stopping power, heat capacity, and thermal conductivity are relevant parameters. Here we compare these parameters for bismuth and gold. We have fabricated electroplated gold, electroplated gold/electroplated bismuth, and evaporated gold/evaporated bismuth 8x8 absorber arrays and find that a correlation exists between the residual resistance ratio (RRR) and thin film microstructure. This finding indicates that we can tailor absorber material conductivity via microstructure alteration, so as to permit absorber thermalization on timescales suitable for high energy resolution x-ray microcalorimetry. We show that by incorporating absorbers possessing large grain size, including electroplated gold and electroplated gold/electroplated bismuth, into our current Mo/Au TES, devices with tunable heat capacity and energy resolution of 2.3 eV (gold) and 2.1 eV (gold/bismuth) FWHM at 6 keV have been fabricated.

  10. Aluminum-Titanium Bilayer for Near-Infrared Transition Edge Sensors.

    Science.gov (United States)

    Lolli, Lapo; Taralli, Emanuele; Portesi, Chiara; Rajteri, Mauro; Monticone, Eugenio

    2016-06-23

    Transition-edge sensors (TESs) are single photon detectors attractive for applications in quantum optics and quantum information experiments owing to their photon number resolving capability. Nowadays, high-energy resolution TESs for telecommunication are based on either W or Au/Ti films, demonstrating slow recovery time constants. We report our progress on the development of an Al/Ti TES. Since bulk aluminum has a critical temperature (Tc) of ca. 1.2 K and a sufficiently low specific heat (less than 10(-4) J/cm³K²), it can be employed to produce the sensitive material for optical TESs. Furthermore, exploiting its high Tc, Al-based TESs can be trimmed in a wider temperature range with respect to Ti or W. A first Al/Ti TES with a Tc ≈ 142 mK, investigated from a thermal and optical point of view, has shown a response time constant of about 2 μs and single photon discrimination with 0.34 eV energy resolution at telecom wavelength, demonstrating that Al/Ti films are suitable to produce TESs for visible and NIR photon counting.

  11. David Peck Todd and the transit of 1882: A lover's triangle forms while an astronomer triangulates the distance to the Sun

    Science.gov (United States)

    Sheehan, W. P.

    2003-12-01

    The transit of Venus of 1882 was a remarkable event, the last transit in the 19th century and the last one to occur until our own time. Among those who undertook to study the transit was David Todd of Amherst College, who, when he was not included in the U.S. Naval Observatory's expeditions, was hired by the Lick Observatory trust to observe the transit from their site-in-development, Mt. Hamilton. Todd went west for the transit just as his wife and Austin Dickinson, Emily's brother, crossed a Rubicon in their love-affair. He successfully photographed the transit from Mt. Hamilton and the plates have survived. In time for the 2004 transit, Tony Misch of Lick and I have scanned them and presented them in cinematographic form and our transit-of-Venus movie will receive its American premiere.

  12. Near-infrared single-photon spectroscopy of a whispering gallery mode resonator using energy-resolving transition edge sensors

    CERN Document Server

    Förtsch, Michael; Stevens, Martin J; Strekalov, Dmitry; Schunk, Gerhard; Fürst, Josef U; Vogl, Ulrich; Sedlmeir, Florian; Schwefel, Harald G L; Leuchs, Gerd; Nam, Sae Woo; Marquardt, Christoph

    2014-01-01

    We demonstrate a method to perform spectroscopy of near-infrared single photons without the need of dispersive elements. This method is based on a photon energy resolving transition edge sensor and is applied for the characterization of widely wavelength tunable narrow-band single photons emitted from a crystalline whispering gallery mode resonator. We measure the emission wavelength of the generated signal and idler photons with an uncertainty of up to 2 nm.

  13. Precise Estimates of the Physical Parameters for the Exoplanet System HD 17156 Enabled by Hubble Space Telescope Fine Guidance Sensor Transit and Asteroseismic Observations

    DEFF Research Database (Denmark)

    Nutzman, Philip; Gilliland, Ronald L.; McCullough, Peter R.

    2011-01-01

    We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors on board the Hubble Space Telescope. We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio Rp /R sstarf = 0.07454 ± 0.00035, in......We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors on board the Hubble Space Telescope. We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio Rp /R sstarf = 0.07454 ± 0...

  14. Sit-stand and stand-sit transitions in older adults and patients with Parkinson's disease : event detection based on motion sensors versus force plates

    NARCIS (Netherlands)

    Zijlstra, Agnes; Mancini, Martina; Lindemann, Ulrich; Chiari, Lorenzo; Zijlstra, Wiebren

    2012-01-01

    Background: Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as

  15. Sit-stand and stand-sit transitions in older adults and patients with Parkinson's disease : event detection based on motion sensors versus force plates

    NARCIS (Netherlands)

    Zijlstra, Agnes; Mancini, Martina; Lindemann, Ulrich; Chiari, Lorenzo; Zijlstra, Wiebren

    2012-01-01

    Background: Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as

  16. Sun Safe Mode Controller Design for LADEE

    Science.gov (United States)

    Fusco, Jesse C.; Swei, Sean S. M.; Nakamura, Robert H.

    2015-01-01

    This paper presents the development of sun safe controllers which are designed to keep the spacecraft power positive and thermally balanced in the event an anomaly is detected. Employed by NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE), the controllers utilize the measured sun vector and the spacecraft body rates for feedback control. To improve the accuracy of sun vector estimation, the least square minimization approach is applied to process the sensor data, which is proven to be effective and accurate. To validate the controllers, the LADEE spacecraft model engaging the sun safe mode was first simulated and then compared with the actual LADEE orbital fight data. The results demonstrated the applicability of the proposed sun safe controllers.

  17. Implications of weak-link behavior on the performance of Mo/Au bilayer transition-edge sensors

    Science.gov (United States)

    Smith, Stephen J.; Adams, Joseph S.; Bailey, Catherine N.; Bandler, Simon R.; Busch, Sarah E.; Chervenak, James A.; Eckart, Megan E.; Finkbeiner, Fred M.; Kilbourne, Caroline A.; Kelley, Richard L.; Lee, Sang-Jun; Porst, Jan-Patrick; Porter, Frederick S.; Sadleir, John E.

    2013-08-01

    Understanding the physical properties of the superconducting-to-normal transition is fundamental for optimizing the design and performance of transition-edge sensors (TESs). Recent critical current IC measurements of square Mo/Au bilayer structures show that they act as weak superconducting links, exhibiting oscillatory, Fraunhofer-like behavior with applied magnetic field. In this paper, we investigate the implications of this behavior for TES x-ray detectors operated in the resistive transition. These devices include normal metal features used for absorber attachment and suppression of detector noise. We present extensive measurements of IC as a function of temperature T and field B, which show a complex temperature and current evolution when compared with the behavior expected from a simple geometry. We introduce a resistively shunted junction model for describing the TES resistive transition as a function of current I, temperature T, and magnetic field B. From this model, we calculate the R(T,I,B) transition and the logarithmic resistance sensitivity with respect to T and I (α and β, respectively), as a function of applied magnetic field and operating point within the resistive transition. Different examples are presented to illustrate the role of critical current on the transition parameters, and results are qualitatively compared with measurements. Results show that the important device parameters α and β exhibit oscillatory behavior with applied magnetic field due to the modulation of the critical current. This in turn affects the signal responsivity and noise, and the predicted energy resolution. These results show the significance of the critical current in determining the performance of TESs and how externally applied and self-induced magnetic fields can affect the transition and, thus, hold promise for future optimization.

  18. Fabrication of smart chemical sensors based on transition-doped-semiconductor nanostructure materials with µ-chips.

    Science.gov (United States)

    Rahman, Mohammed M; Khan, Sher Bahadar; Asiri, Abdullah M

    2014-01-01

    Transition metal doped semiconductor nanostructure materials (Sb2O3 doped ZnO microflowers, MFs) are deposited onto tiny µ-chip (surface area, ∼0.02217 cm(2)) to fabricate a smart chemical sensor for toxic ethanol in phosphate buffer solution (0.1 M PBS). The fabricated chemi-sensor is also exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards ethanol. The calibration plot is linear (r(2) = 0.9989) over the large ethanol concentration ranges (0.17 mM to 0.85 M). The sensitivity and detection limit is ∼5.845 µAcm(-2)mM(-1) and ∼0.11±0.02 mM (signal-to-noise ratio, at a SNR of 3) respectively. Here, doped MFs are prepared by a wet-chemical process using reducing agents in alkaline medium, which characterized by UV/vis., FT-IR, Raman, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) etc. The fabricated ethanol chemical sensor using Sb2O3-ZnO MFs is simple, reliable, low-sample volume (<70.0 µL), easy of integration, high sensitivity, and excellent stability for the fabrication of efficient I-V sensors on μ-chips.

  19. Sun and Sun Worship in Different Cultures

    Science.gov (United States)

    Farmanyan, S. V.; Mickaelian, A. M.

    2014-10-01

    The Sun symbol is found in many cultures throughout history, it has played an important role in shaping our life on Earth since the dawn of time. Since the beginning of human existence, civilisations have established religious beliefs that involved the Sun's significance to some extent. As new civilisations and religions developed, many spiritual beliefs were based on those from the past so that there has been an evolution of the Sun's significance throughout cultural development. For comparing and finding the origin of the Sun we made a table of 66 languages and compared the roots of the words. For finding out from where these roots came from, we also made a table of 21 Sun Gods and Goddesses and proved the direct crossing of language and mythology.

  20. High-resolution gamma-ray spectroscopy with a microwave-multiplexed transition-edge sensor array

    CERN Document Server

    Noroozian, Omid; Bennett, Douglas A; Brevik, Justus A; Fowler, Joseph W; Gao, Jiansong; Hilton, Gene C; Horansky, Robert D; Irwin, Kent D; Kang, Zhao; Schmidt, Daniel R; Vale, Leila R; Ullom, Joel N

    2013-01-01

    We demonstrate very high resolution photon spectroscopy with a microwave-multiplexed two-pixel transition-edge sensor (TES) array. We measured a $^{153}$Gd photon source and achieved an energy resolution of 63 eV full-width-at-half-maximum at 97 keV and an equivalent readout system noise of 86 pA/$\\sqrt{\\text{Hz}}$ at the TES. The readout circuit consists of superconducting microwave resonators coupled to radio-frequency superconducting-quantum-interference-devices (SQUID) and transduces changes in input current to changes in phase of a microwave signal. We use flux-ramp modulation to linearize the response and evade low-frequency noise. This demonstration establishes one path for the readout of cryogenic X-ray and gamma-ray sensor arrays with more than $10^3$ elements and spectral resolving powers $R=\\lambda/\\Delta\\lambda > 10^3$.

  1. Sun's rap song

    Science.gov (United States)

    Hogan, M.; Lee, W.

    1995-07-01

    We present a rap song composed for the Sun, our star. This Sun's Rap Song can be utilized in classroom teaching to spark the students' interest and facilitate the students' learning of the relevant subjects.

  2. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  3. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  4. Virtual Sensor for Failure Detection, Identification and Recovery in the Transition Phase of a Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Guillermo Heredia

    2010-03-01

    Full Text Available The Helicopter Adaptive Aircraft (HADA is a morphing aircraft which is able to take-off as a helicopter and, when in forward flight, unfold the wings that are hidden under the fuselage, and transfer the power from the main rotor to a propeller, thus morphing from a helicopter to an airplane. In this process, the reliable folding and unfolding of the wings is critical, since a failure may determine the ability to perform a mission, and may even be catastrophic. This paper proposes a virtual sensor based Fault Detection, Identification and Recovery (FDIR system to increase the reliability of the HADA aircraft. The virtual sensor is able to capture the nonlinear interaction between the folding/unfolding wings aerodynamics and the HADA airframe using the navigation sensor measurements. The proposed FDIR system has been validated using a simulation model of the HADA aircraft, which includes real phenomena as sensor noise and sampling characteristics and turbulence and wind perturbations.

  5. The systematic radial downflow in the transition region of the quiet sun from limb-to-limb observations of the C IV resonance lines

    Science.gov (United States)

    Rottman, Gary J.; Hassler, Donald D.; Jones, Michael D.; Orrall, Frank Q.

    1990-08-01

    This paper presents absolute velocities of C IV 1548, 1550 nm measured as a function of position along the solar equator, which was free of both active regions and coronal holes, and uniformly representative of the quiet sun. These observations were made with moderate spatial resolution (18 arcsec) using an EUV spectrometer dedicated to measuring absolute wavelengths (velocities) by direct comparison with a platinum spectrum generated on board the sounding rocket. On the assumption that systematic horizontal motions cancel statistically so that the line-of-sight velocities approach zero at the limb, a net radial downflow of 7.5 + or - 1.0 km/sec was found. The assumption was tested using the wavelength reference and found to be valid within the absolute accuracy of the rest wavelengths of the C IV lines.

  6. Wearable Barometric Pressure Sensor to Improve Postural Transition Recognition of Mobility-Impaired Stroke Patients.

    Science.gov (United States)

    Masse, Fabien; Gonzenbach, Roman; Paraschiv-Ionescu, Anisoara; Luft, Andreas R; Aminian, Kamiar

    2016-11-01

    Sit-to-stand and Stand-to-sit transfers (STS) provide relevant information regarding the functional limitation of mobility-impaired patients. The characterization of STS pattern using a single trunk fixed inertial sensor has been proposed as an objective tool to assess changes in functional ability and balance due to disease. Despite significant research efforts, STS quantification remains challenging due to the high inter- and between- subject variability of this motion pattern. The present study aims to improve the performance of STS detection and classification by fusing the information from barometric pressure (BP) and inertial sensors while keeping a single sensor located at the trunk. A total number of 345 STSs were recorded from 12 post-stroke patients monitored in a semi-structured conditioned protocol. Model-based features of BP signal were combined with kinematic parameters from accelerometer and/or gyroscope and used in a logistic regression-based classifier to detect STS and then identify their types. The correct classification rate was 90.6% with full sensor (BP and inertial) configuration and 75.4% with single inertial sensor. Receiver-Operating-Characteristics analysis was carried out to characterize the robustness of the models. The results demonstrate the potential of BP sensor to improve the detection and classification of STSs when monitoring is performed unobtrusively in every-day life.

  7. Seasons by the Sun

    Science.gov (United States)

    Stark, Meri-Lyn

    2005-01-01

    Understanding the Sun has challenged people since ancient times. Mythology from the Greek, Inuit, and Inca cultures attempted to explain the daily appearance and nightly disappearance of the Sun by relating it to a chariot being chased across the sky. While people no longer believe the Sun is a chariot racing across the sky, teachers are still…

  8. Personal, Seasonal Suns

    Science.gov (United States)

    Sutley, Jane

    2010-01-01

    This article presents an art project designed for upper-elementary students to (1) imagine visual differences in the sun's appearance during the four seasons; (2) develop ideas for visually translating their personal experiences regarding the seasons to their sun drawings; (3) create four distinctive seasonal suns using colors and imagery to…

  9. Refractometric sensor based on induced losses in the region of transition from a curved side-polished POF fiber

    Science.gov (United States)

    Lomer, M.; Galindez, C. A.; Quintela, M. A.; Quintela, A.; Mirapeix, J.; Lopez-Higuera, J. M.

    2008-04-01

    A refractometric sensor that uses the transition region of a U-bent Plastic Optical Fiber (POF) when it is polished laterally is presented. By polishing a lateral segment of the fiber, a part of the plastic optical fiber core is removed and an elliptical surface is formed on the bend. It is found that that the polishing with an angle equals to the critical angle of a straight optical fiber the sensitivity of this transducer structure is enhanced. Then, the incident light is totally reflected and the transition losses decrease locally. In addition, the sensitivity increases compared to the polishing in the region of bending losses. The proposed transducer is successfully checked with experimental measurements and different kinds of liquids. Potential applications are suggested.

  10. 太阳同步轨道星敏感器热设计典型工况确定%Typical work states analysis on thermal design of the sun-synchronous orbit star sensors

    Institute of Scientific and Technical Information of China (English)

    关奉伟

    2015-01-01

    以某太阳同步轨道卫星星敏感器为例,阐述了热环境分析、外热流计算、典型工况条件确定以及热试验模拟的全过程。首先,分析了星敏感器所处的内、外部热环境,确定了其温度水平的主要影响因素。其次,进行了星敏感器通光孔到达外热流的计算,确定了典型工况的工况条件。然后,制定了星敏感器热平衡试验外热流的模拟方案,利用闭环程控系统进行外热流加载。最后,依据星敏感器自身特点,提出了热试验外热流的加载策略。典型工况条件的确定合理可行。%The whole process of thermal environment analysis,space heat flux calculation,typical work states analysis and heat flux simulation for thermal test is expatiated for a given star sensors working on sun-synchronous orbit.Firstly,the inner and outer thermal environments of the star sensors were analyzed,and the main influential fac-tors on temperature level were determined.Secondly,heat fluxes that reach the given star sensors were calculated,and the typical work state conditions were obtained.Thirdly,the space heat flux simulation scheme of heat balance test was determined,and closed loop programmable system was applied to load heat flux.Finally,the space heat flux simulation method and tactic of thermal test is proposed according to the characteristics of the star sensors.It proves that the typi-cal work states are rational and feasible.

  11. The Hetu'u Global Network: Measuring the Distance to the Sun Using the June 5th/6th Transit of Venus

    Science.gov (United States)

    Faherty, Jacqueline K.; Rodriguez, David R.; Miller, Scott T.

    2012-01-01

    In the spirit of historic astronomical endeavors, we invited school groups across the globe to collaborate in a solar distance measurement using the rare June 5/6th transit of Venus. In total, we recruited 19 school groups spread over 6 continents and 10 countries to participate in our Hetu'u Global Network. Applying the methods of French…

  12. Application of Photoelectric Position Sensor in High Precision Automatic Sun Tracker%光电位置传感器在高精度太阳自动对准中的应用

    Institute of Scientific and Technical Information of China (English)

    曲春英; 卞秀芬

    2016-01-01

    To improve the utilization rate of solar energy,the current problems of sun tracking is analyzed,the solar spotlight system is developed based on photoelectric position sensor;the tracking device is designed to achieve sta⁃bility;tracking strategy adopts photoelectric tracking combined with calendar-reckoning,and all-weather automatic tracking was realized. Experimental results show the method is simple,and it has high tracking precision,good sta⁃bility.%分析了目前太阳跟踪方式中存在的问题,为进一步提高太阳跟踪精度和利用率,设计了基于光电位置传感器的太阳追光系统;设计了跟踪装置,达到了跟踪的稳定性;跟踪策略上采用光电跟踪与视日跟踪相结合,实现了全天候自动跟踪。经试验表明:该方法简单,跟踪精度高,稳定性好。

  13. Dry Electrodes for ECG and Pulse Transit Time for Blood Pressure: A Wearable Sensor and Smartphone Communication Approach

    Science.gov (United States)

    Shyamkumar, Prashanth

    -invasive, cuff-less Blood pressure estimation based on Pulse Transit Time with multiple synchronized sensor nodes, is implemented with e-nanoflex and the results are discussed.

  14. Proximity gettering of C3H5 carbon cluster ion-implanted silicon wafers for CMOS image sensors: Gettering effects of transition metal, oxygen, and hydrogen impurities

    Science.gov (United States)

    Kurita, Kazunari; Kadono, Takeshi; Okuyama, Ryousuke; Hirose, Ryo; Onaka-Masada, Ayumi; Koga, Yoshihiro; Okuda, Hidehiko

    2016-12-01

    A new technique is described for manufacturing silicon wafers with the highest capability yet reported for gettering transition metallic, oxygen, and hydrogen impurities in CMOS image sensor fabrication. It is demonstrated that this technique can implant wafers simultaneously with carbon and hydrogen elements that form the projection range by using hydrocarbon compounds. Furthermore, these wafers can getter oxygen impurities out-diffused from the silicon substrate to the carbon cluster ion projection range during heat treatment. Therefore, they can reduce the formation of transition metals and oxygen-related defects in the device active regions and improve electrical performance characteristics, such as dark current and image lag characteristics. The new technique enables the formation of high-gettering-capability sinks for transition metals, oxygen, and hydrogen impurities under device active regions of CMOS image sensors. The wafers formed by this technique have the potential to significantly reduce dark current in advanced CMOS image sensors.

  15. Comparison of Water Vapor Measurements by Airborne Sun photometer and Near-Coincident In Situ and Satellite Sensors during INTEX-ITCT 2004

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, J.; Schmid, Beat; Redemann, Jens; Russell, P. B.; Ramirez, Samuel; Eilers, J.; Gore, W.; Howard, Samuel; Pommier, J.; Fetzer, E. J.; Seemann, S. W.; Borbas, E.; Wolfe, Daniel; Thompson, Anne M.

    2007-06-06

    We have retrieved columnar water vapor (CWV) from measurements acquired by the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) during 19 Jetstream 31 (J31) flights over the Gulf of Maine in summer 2004. In this paper we compare AATS-14 water vapor retrievals during aircraft vertical profiles with measurements by an onboard Vaisala HMP243 humidity sensor and by ship radiosondes, and with water vapor profiles retrieved from AIRS measurements during 8 Aqua overpasses. We also compare AATS CWV and MODIS infrared CWV retrievals during 5 Aqua and 5 Terra overpasses. For 35 J31 vertical profiles mean (bias) and rms AATS-minus-Vaisala layer-integrated water vapor (LWV) differences are -7.1% and 8.8%, respectively. For 22 aircraft profiles within 1 h and 130 km of radiosonde soundings, AATS-minus-sonde bias and rms LWV differences are -5.4% and 8.8%, respectively, and corresponding J31 Vaisala-minus-sonde differences are 2.3% and 8.4%, respectively. AIRS LWV retrievals within 80 km of J31 profiles yield lower bias and rms differences compared to AATS or Vaisala retrievals than do AIRS retrievals within 150 km of the J31. In particular, for AIRS-minus-AATS LWV differences, the bias decreases from 8.8% to 5.8%, and the rms difference decreases from 21.5% to 16.4%. Comparison of vertically resolved AIRS water vapor retrievals (LWVA) to AATS values in fixed pressure layers yields biases of -2% to +6% and rms differences of ~20% below 700 hPa. Variability and magnitude of these differences increase significantly above 700 hPa. MODIS IR retrievals of CWV in 205 grid cells (5 x 5-km at nadir) are biased wet by 10.4% compared to AATS over-ocean near surface retrievals. The MODIS Aqua subset (79 grid cells) exhibits a wet bias of 5.1%, and the MODIS-Terra subset (126 grid cells) yields a wet bias of 13.2%.

  16. First application of superconducting transition-edge-sensor microcalorimeters to hadronic-atom x-ray spectroscopy

    CERN Document Server

    Okada, S; Curceanu, C; Doriese, W B; Fowler, J W; Gard, J; Gustafsson, F P; Hashimoto, T; Hayano, R S; Hirenzaki, S; Hays-Wehle, J P; Hilton, G C; Ikeno, N; Iliescu, M; Ishimoto, S; Itahashi, K; Iwasaki, M; Koike, T; Kuwabara, K; Ma, Y; Marton, J; Noda, H; O'Neil, G C; Outa, H; Reintsema, C D; Sato, M; Schmidt, D R; Shi, H; Suzuki, K; Suzuki, T; Swetz, D S; Tatsuno, H; Uhlig, J; Ullom, J N; Widmann, E; Yamada, S; Yamagata-Sekihara, J; Zmeskal, J

    2016-01-01

    High-resolution pionic-atom x-ray spectroscopy was performed with an x-ray spectrometer based on a 240-pixel array of superconducting transition-edge-sensor (TES) microcalorimeters at the piM1 beam line of the Paul Scherrer Institute. X-rays emitted by pionic carbon via the 4f->3d transition and the parallel 4d->3p transition were observed with a full-width-at-half-maximum energy resolution of 6.8 eV at 6.4 keV. Measured x-ray energies are consistent with calculated electromagnetic values which considered the strong-interaction effect assessed via the Seki-Masutani potential for the 3p energy level, and favor the electronic population of two filled 1s electrons in the K-shell. Absolute energy calibration with an uncertainty of 0.1 eV was demonstrated under a high-rate hadron beam condition of 1.45 MHz. This is the first application of a TES spectrometer to hadronic-atom x-ray spectroscopy and is an important milestone towards next-generation high-resolution kaonic-atom x-ray spectroscopy.

  17. Proposal for a GHz count rate near-IR single-photon detector based on a nanoscale superconducting transition edge sensor

    CERN Document Server

    Santavicca, Daniel F; Prober, Daniel E; 10.1117/12.883979

    2012-01-01

    We describe a superconducting transition edge sensor based on a nanoscale niobium detector element. This device is predicted to be capable of energy-resolved near-IR single-photon detection with a GHz count rate. The increased speed and sensitivity of this device compared to traditional transition edge sensors result from the very small electronic heat capacity of the nanoscale detector element. In the present work, we calculate the predicted thermal response time and energy resolution. We also discuss approaches for achieving efficient optical coupling to the sub-wavelength detector element using a resonant near-IR antenna.

  18. Improved Laboratory Transition Probabilities for Er II and Applications to the Erbium Abundances of the Sun and Five r-Process Rich, Metal-Poor Stars

    CERN Document Server

    Lawler, J E; Cowan, J J; Wyart, J -F; Ivans, I I; Sobeck, J S; Stockett, M H; Hartog, E A Den

    2008-01-01

    Recent radiative lifetime measurements accurate to +/- 5% (Stockett et al. 2007, J. Phys. B 40, 4529) using laser-induced fluorescence (LIF) on 8 even-parity and 62 odd-parity levels of Er II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 418 lines of Er II. This work moves Er II onto the growing list of rare earth spectra with extensive and accurate modern transition probability measurements using LIF plus FTS data. This improved laboratory data set has been used to determine a new solar photospheric Er abundance, log epsilon = 0.96 +/- 0.03 (sigma = 0.06 from 8 lines), a value in excellent agreement with the recommended meteoric abundance, log epsilon = 0.95 +/- 0.03. Revised Er abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, HD 221170, HD 115444, and CS 31082-001. For these five stars the average Er/Eu abundance ratio, = 0.42, is in very good agreement ...

  19. Particle Discrimination in TeO$_{2}$ Bolometers using Light Detectors read out by Transition Edge Sensors

    CERN Document Server

    Schäffner, K; Bellini, F; Casali, N; Ferroni, F; Hauff, D; Nagorny, N; Pattavina, L; Petricca, F; Pirro, S; Pröbst, F; Reindl, F; Seidel, W; Strauss, R

    2014-01-01

    An active discrimination of the dominant $\\alpha$-background is the prerequisite for future DBD experiments based on TeO$_{2}$ bolometers. We investigate such $\\alpha$-particle rejection in cryogenic TeO$_{2}$ bolometers by the detection of Cherenkov light. For a setup consisting of a large TeO$_{2}$ crystal 285 g and a separate cryogenic light detector, both read out by transition edge sensors at around 10 mK, we obtain an event-by-event identification of e/$\\gamma$- and $\\alpha$-events. In the energy interval ranging from 2400 keV to 2800 keV and covering the Q-value of $^{130}$Te a discrimination power of 3.7 could be demonstrated.

  20. Design and Optimization of Multi-Pixel Transition-Edge Sensors for X-Ray Astronomy Applications

    Science.gov (United States)

    Smith, Stephen J.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron Michael; Eckart, Megan E.; Ewin, Audrey J.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; hide

    2017-01-01

    Multi-pixel transition-edge sensors (TESs), commonly referred to as 'hydras', are a type of position sensitive micro-calorimeter that enables very large format arrays to be designed without commensurate increase in the number of readout channels and associated wiring. In the hydra design, a single TES is coupled to discrete absorbers via varied thermal links. The links act as low pass thermal filters that are tuned to give a different characteristic pulse shape for x-ray photons absorbed in each of the hydra sub pixels. In this contribution we report on the experimental results from hydras consisting of up to 20 pixels per TES. We discuss the design trade-offs between energy resolution, position discrimination and number of pixels and investigate future design optimizations specifically targeted at meeting the readout technology considered for Lynx.

  1. A Comparison of Fundamental Noise in Kinetic Inductance Detectors and Transition Edge Sensors for Millimeter-wave Applications

    CERN Document Server

    Lowitz, A E; Golwala, S R; Timbie, P T

    2014-01-01

    Kinetic inductance detectors (KIDs) show promise as a competitive technology for astronomical observations over a wide range of wavelengths. We are interested in comparing the fundamental limitations to the sensitivity of KIDs with that of transition edge sensors (TESs) at millimeter wavelengths, specifically over the wavelengths required for studies of the Cosmic Microwave Background (CMB). We calculate the total fundamental noise arising from optical and thermal excitations in TESs and KIDs for a variety of bath temperatures and optical loading scenarios for applications at millimeter wavelengths. Special consideration is given to the case of ground-based observations of 100 GHz radiation with a 100 mK bath temperature, conditions consistent with the planned second module of the QUBIC telescope, a CMB instrument. Under these conditions, a titanium nitride KID with optimized critical temperature pays a few percent noise penalty compared to a typical optimized TES.

  2. Performance of horn-coupled transition edge sensors for L- and S-band optical detection on the SAFARI instrument

    Science.gov (United States)

    Goldie, D. J.; Glowacka, D. M.; Withington, S.; Chen, Jiajun; Ade, P. A. R.; Morozov, D.; Sudiwala, R.; Trappe, N. A.; Quaranta, O.

    2016-07-01

    We describe the geometry, architecture, dark- and optical performance of ultra-low-noise transition edge sensors as THz detectors for the SAFARI instrument. The TESs are fabricated from superconducting Mo/Au bilayers coupled to impedance-matched superconducting β-phase Ta thin-film absorbers. The detectors have phonon-limited dark noise equivalent powers of order 0.5 - 1.0 aW/ √ Hz and saturation powers of order 20 - 40 fW. The low temperature test configuration incorporating micro-machined backshorts is also described, and construction and typical performance characteristics for the optical load are shown. We report preliminary measurements of the optical performance of these TESs for two SAFARI bands; L-band at 110 - 210 μm and S-band 34 - 60 μm .

  3. Balloon-Borne System Would Aim Instrument Toward Sun

    Science.gov (United States)

    Polites, M. E.

    1992-01-01

    Proposed system including digital control computer, control sensors, and control actuators aims telescope or other balloon-borne instrument toward Sun. Pointing system and instrument flown on gondola, suspended from balloon. System includes reaction wheel, which applies azimuthal control torques to gondola, and torque motor to apply low-frequency azimuthal torques between gondola and cable. Three single-axis rate gyroscopes measure yaw, pitch, and roll. Inclinometer measures roll angle. Two-axis Sun sensor measures deviation, in yaw and pitch, of attitude of instrument from line to apparent center of Sun. System provides initial coarse pointing, then maintains fine pointing.

  4. Spin Transition Sensors Based on β-Amino-Acid 1,2,4-Triazole Derivative

    Directory of Open Access Journals (Sweden)

    Aurelian Rotaru

    2011-08-01

    Full Text Available A β-aminoacid ester was successfully derivatized to yield to 4H-1,2-4-triazol-4-yl-propionate (βAlatrz which served as a neutral bidentate ligand in the 1D coordination polymer [Fe(βAlatrz3](CF3SO32·0.5H2O (1·0.5H2O. The temperature dependence of the high-spin molar fraction derived from 57Fe Mossbauer spectroscopy recorded on cooling below room temperature reveals an exceptionally abrupt single step transition between high-spin and low-spin states with a hysteresis loop of width 4 K (Tc↑ = 232 K and Tc↓ = 228 K in agreement with magnetic susceptibility measurements. The material presents striking reversible thermochromism from white, at room temperature, to pink on quench cooling to liquid nitrogen, and acts as an alert towards temperature variations. The phase transition is of first order, as determined by differential scanning calorimetry, with transition temperatures matching the ones determined by SQUID and Mössbauer spectroscopy. The freshly prepared sample of 1·0.5H2O, dried in air, was subjected to annealing at 390 K, and the obtained white compound [Fe(βAlatrz3](CF3SO32 (1 was found to exhibit a similar spin transition curve however much temperature was increased by (Tc↑ = 252 K and Tc↓ = 248 K. The removal of lattice water molecules from 1·0.5H2O is not accompanied by a change of the morphology and of the space group, and the chain character is preserved. However, an internal pressure effect stabilizing the low-spin state is evidenced.

  5. Spin transition sensors based on β-amino-acid 1,2,4-triazole derivative.

    Science.gov (United States)

    Dîrtu, Marinela M; Schmit, France; Naik, Anil D; Rotaru, Aurelian; Marchand-Brynaert, J; Garcia, Yann

    2011-01-01

    A β-aminoacid ester was successfully derivatized to yield to 4H-1,2-4-triazol-4-yl-propionate (βAlatrz) which served as a neutral bidentate ligand in the 1D coordination polymer [Fe(βAlatrz)(3)](CF(3)SO(3))(2)·0.5H(2)O (1·0.5H(2)O). The temperature dependence of the high-spin molar fraction derived from (57)Fe Mossbauer spectroscopy recorded on cooling below room temperature reveals an exceptionally abrupt single step transition between high-spin and low-spin states with a hysteresis loop of width 4 K (T(c) (↑) = 232 K and T(c) (↓) = 228 K) in agreement with magnetic susceptibility measurements. The material presents striking reversible thermochromism from white, at room temperature, to pink on quench cooling to liquid nitrogen, and acts as an alert towards temperature variations. The phase transition is of first order, as determined by differential scanning calorimetry, with transition temperatures matching the ones determined by SQUID and Mössbauer spectroscopy. The freshly prepared sample of 1·0.5H(2)O, dried in air, was subjected to annealing at 390 K, and the obtained white compound [Fe(βAlatrz)(3)](CF(3)SO(3))(2) (1) was found to exhibit a similar spin transition curve however much temperature was increased by (T(c) (↑) = 252 K and T(c) (↓) = 248 K). The removal of lattice water molecules from 1·0.5H(2)O is not accompanied by a change of the morphology and of the space group, and the chain character is preserved. However, an internal pressure effect stabilizing the low-spin state is evidenced.

  6. Electromagnetic Design of Feedhorn-Coupled Transition-Edge Sensors for Cosmic Microwave Background Polarimetery

    Science.gov (United States)

    Chuss, David T.

    2011-01-01

    Observations of the cosmic microwave background (CMB) provide a powerful tool for probing the evolution of the early universe. Specifically, precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. A key technological element on the path to the measurement of this faint signal is the capability to produce large format arrays of background-limited detectors. We describe the electromagnetic design of feedhorn-coupled, TES-based sensors. Each linear orthogonal polarization from the feed horn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly-symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization. Care has been taken in the design to eliminate stray coupling paths to the absorbers. These detectors will be fielded in the Cosmology Large Angular Scale Surveyor (CLASS).

  7. Pressure Sensor via Optical Detection Based on a 1D Spin Transition Coordination Polymer

    Directory of Open Access Journals (Sweden)

    Cătălin M. Jureschi

    2015-01-01

    Full Text Available We have investigated the suitability of using the 1D spin crossover coordination polymer [Fe(4-(2’-hydroxyethyl-1,2,4-triazole3]I2∙H2O, known to crossover around room temperature, as a pressure sensor via optical detection using various contact pressures up to 250 MPa. A dramatic persistent colour change is observed. The experimental data, obtained by calorimetric and Mössbauer measurements, have been used for a theoretical analysis, in the framework of the Ising-like model, of the thermal and pressure induced spin state switching. The pressure (P-temperature (T phase diagram calculated for this compound has been used to obtain the P-T bistability region.

  8. Electromagnetic Design of Feedhorn-Coupled Transition-Edge Sensors for Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Chuss, D. T.; Bennett, C. L.; Costen, N.; Crowe, E.; Denis, K.; Eimer, J. R.; Lourie, N.; Marriage, T. A.; Moseley, S. H.; Rostem, K.; Stevenson, T. R.; Towner, D.; U-Yen, K.; Voellmer, G.; Wollack, E. J.; Zeng, L.

    2012-06-01

    Observations of the cosmic microwave background (CMB) provide a powerful tool for probing the evolution of the early universe. Specifically, precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. A key technological element on the path to the measurement of this faint signal is the capability to produce large format arrays of background-limited detectors. We describe the electromagnetic design of feedhorn-coupled, TES-based sensors. Each linear orthogonal polarization from the feedhorn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly-symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization. Care has been taken in the design to eliminate stray coupling paths to the absorbers. These detectors will be fielded in the Cosmology Large Angular Scale Surveyor (CLASS).

  9. Sun-Earth Days

    Science.gov (United States)

    Thieman, J.; Ng, C.; Lewis, E.; Cline, T.

    2010-08-01

    Sun-Earth Day is a well-coordinated series of programs, resources and events under a unique yearly theme highlighting the fundamentals of heliophysics research and missions. A menu of activities, conducted throughout the year, inspire and educate participants. Sun-Earth Day itself can vary in date, but usually is identified by a celebration on or near the spring equinox. Through the Sun-Earth Day framework we have been able to offer a series of coordinated events that promote and highlight the Sun, its connection to Earth and the other planets. Sun-Earth Day events are hosted by educators, museums, amateur astronomers and scientists and occur at schools, community groups, parks, planetaria and science centers around the globe. Sun-Earth Day raises the awareness and knowledge of formal and informal education audiences concerning space weather and heliophysics. By building on the success of Sun-Earth Day yearly celebrations, we seek to affect people of all backgrounds and ages with the wonders of heliophysics science, discovery, and exploration in ways that are both tangible and meaningful to their lives.

  10. Sun-Earth Day Connects History, Culture and Science

    Science.gov (United States)

    Cline, T.; Thieman, J.

    2003-12-01

    The NASA Sun-Earth Connection Education forum annually promotes and event called Sun-Earth Day: a national celebration of the Sun, the space around the Earth (geospace), and how all of it affects life on our planet. For the past 3 years this event has provided a venue by which classrooms, museums, planetaria, and at NASA centers have had a sensational time sharing stories, images, and activities related to the Sun-Earth connections and the views o fthe Sun from Earth. Each year we select a different theme by which NASA Space Science can be further related to cross-curricular activities. Sun-Earth Day 2002, "Celebrate the Equinox", drew parallels between Native American Cultures and NASA's Sun-Earth Connection research via cultural stories, interviews, web links, activities and Native American participation. Sun-Earth Day 2003, "Live From the Aurora", shared the beauty of the Aurora through a variety of activities and stories related to perspectives of Northern Peoples. Sun-Earth Day 2004 will share the excitement of the transit of Venus through comparisons of Venus with Earth and Mars, calculations of the distances to nearby stars, and the use of transits to identify extra-solar planets. Finally, Sun-Earth Day 2005 will bring several of these themes together by turning our focus to the history and culture surrounding ancient observatories such as Chaco Canyon, Machu Picchu, and Chichen Itza.

  11. Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data

    CERN Document Server

    Lawler, J E; Cowan, J J; Ivans, I I; Hartog, E A Den

    2009-01-01

    Recent radiative lifetime measurements accurate to +/- 5% using laser-induced fluorescence (LIF) on 43 even-parity and 15 odd-parity levels of Ce II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 921 lines of Ce II. This improved laboratory data set has been used to determine a new solar photospheric Ce abundance, log epsilon = 1.61 +/- 0.01 (sigma = 0.06 from 45 lines), a value in excellent agreement with the recommended meteoritic abundance, log epsilon = 1.61 +/- 0.02. Revised Ce abundances have also been derived for the r-process-rich metal-poor giant stars BD+17 3248, CS 22892-052, CS 31082-001, HD 115444 and HD 221170. Between 26 and 40 lines were used for determining the Ce abundance in these five stars, yielding a small statistical uncertainty of 0.01 dex similar to the Solar result. The relative abundances in the metal-poor stars of Ce and Eu, a nearly pure r-process element in the Sun, matches r-process ...

  12. Fuzzy image processing in sun sensor

    Science.gov (United States)

    Mobasser, S.; Liebe, C. C.; Howard, A.

    2003-01-01

    This paper will describe how the fuzzy image processing is implemented in the instrument. Comparison of the Fuzzy image processing and a more conventional image processing algorithm is provided and shows that the Fuzzy image processing yields better accuracy then conventional image processing.

  13. Sun and Sjogren's Syndrome

    Science.gov (United States)

    Patient Education Sheet The Sun and Sjögren’s Syndrome The SSF thanks Mona Z. Mofid, MD, FAAD, Diplomate, American Board of Dermatology, and Medical Director, American Melanoma Foundation, San Diego, California, ...

  14. 邢云路对《授时历》日躔过宫推步的改进%The Calculation of Shoushi Li When the Sun Transited Zodiacal Signs Improved by Xing Yunlu

    Institute of Scientific and Technical Information of China (English)

    李勇

    2012-01-01

    The book Gujin Lulikao was written by Xing Yunlu, an ancient astronomer in the latter Ming dynasty. In this paper, base on our previous recovery for both calendars of Shotishi Li and Datong Li, we investigate the Xing's practical calculations for the times and locations when the sun transited zodiacal signs, then check and compare his results with our calculations after accepted Xing's parameters and the methods. First, when using the improving Shoushi methods claimed by Xing, we obtain, in the year of Wanli Jihai (1599), the standard error of the time between our calculations and Xing's results when the sun transit each of the zodiacs is 5.93 Ke (=85.39 min), but when ignore the biggest error derived by Zodiacs Xu, the error will decrease to 1.38 Ke (=19.87 min), and at the same time the standard deviation of solar longitude at middle-night just before transit is 0.06 Du (=0.059°). The second, when employing our recovering methods of Datong Li and comparing with Xing's calculation, we ascertain that in the same year the standard error of the time when the sun transit each of the zodiacs is 1.09 Ke (=15.70 min), and the standard error of solar longitude at middle-night just before transit is 0.005 Du (=0.049°). So we are sure we have recovered the work declared by Xing. And in fact Xing do not improve the method of Shoushi Li but provide the new values of the tropical year-length, the data of Zhoutian Fen (the degrees of the whole ecliptic or celestial equator), and the range of each zodiac. At the same time, the bigger deviations between both calendars derived by Xing just caused by his new parameters, and this probably leads to Xing approving Shoushi Li and despising Datong Li.%考察明末邢云路所撰《古今律历考》中述及的日躔推步实例与先期恢复的《授时历》和《大统历》方法进行推步比对.采用邢云路改进的《授时历》法推步万历已亥岁(1599年)日躔交宫时间,结果与邢氏的标准偏差为5.93

  15. Why Study the Sun?

    Indian Academy of Sciences (India)

    Arvind Bhatnagar

    2006-06-01

    In this presentation we briefly describe the Sun through large number of illustrations and pictures of the Sun taken from early times to the present day space missions. The importance of the study of the Sun is emphasized as it is the nearest star which presents unparallelled views of surface details and numerous phenomena. Our Sun offers a unique celestial laboratory where a large variety of phenomena take place, ranging in temporal domain from a few milliseconds to several decades, in spatial domain from a few hundred kilometers to thousands of kilometers, and in the temperature domain from a few thousand degrees to several million degrees. Its mass motion ranges from thousandths to thousands of kilometers per second. Such an object provides us with a unique laboratory to study the state of matter in the Universe. The existing solar ground-based and space missions have already revealed several mysteries of the outer environment of our Sun and much more is going to come in the near future from planned new sophisticated ground-based solar telescopes and Space missions. The new technique of helioseismology has unravelled many secrets of the solar interior and has put the Standard Solar Model (SSM) on firm footing. The long-standing problem of solar neutrinos has been recently sorted out, and even the ‘back side’ view of the Sun can be seen using the technique of holographic helioseismology.

  16. The Sun and Earth

    Science.gov (United States)

    Gopalswamy, Natchimuthuk

    2012-01-01

    Thus the Sun forms the basis for life on Earth via the black body radiation it emits. The Sun also emits mass in the form of the solar wind and the coronal mass ejections (CMEs). Mass emission also occurs in the form of solar energetic particles (SEPs), which happens during CMEs and solar flares. Both the mass and electromagnetic energy output of the Sun vary over a wide range of time scales, thus introducing disturbances on the space environment that extends from the Sun through the entire heliosphere including the magnetospheres and ionospheres of planets and moons of the solar system. Although our habitat is located in the neutral atmosphere of Earth, we are intimately connected to the non-neutral space environment starting from the ionosphere to the magnetosphere and to the vast interplanetary space. The variability of the solar mass emissions results in the interaction between the solar wind plasma and the magnetospheric plasma leading to huge disturbances in the geospace. The Sun ionizes our atmosphere and creates the ionosphere. The ionosphere can be severely disturbed by the transient energy input from solar flares and the solar wind during geomagnetic storms. The complex interplay between Earth's magnetic field and the solar magnetic field carried by the solar wind presents varying conditions that are both beneficial and hazardous to life on earth. This seminar presents some of the key aspects of this Sun-Earth connection that we have learned since the birth of space science as a scientific discipline some half a century ago.

  17. Ultra-Sensitive Transition-Edge Sensors (TESs) for Far-IR/Submm Space-Borne Spectroscopy

    Science.gov (United States)

    Kenyon, M.; Day, P. K.; Bradford, C. M.; Bock, J .J.; Leduc, H. G.

    2011-01-01

    We have built surface micromachined thin-film metallized Si(x)N(y) optical absorbers for transition-edge sensors (TESs) suitable for the Background - Limited far-IR/Submm Spectrograph (BLISS). BLISS is a broadband (38 micrometers - 433 micrometers), grating spectrometer consisting of five wavebands each with a modest resolution of R (is) approx. 1000. Because BLISS requires the effective noise equivalent power (NEP) of the TES to be below 10 (exp 19) W/Hz(exp 1/2), our TESs consist of four long (1000 micrometers), narrow (0.4 micrometers ), and thin (0.25 micrometers ) Si(x) N(y) support beams that reduce the thermal conductance G between the substrate and the optical absorber. To reduce the heat capacity of the absorber and make the response time tau fast enough for BLISS, our absorbers are patterned into a mesh geometry with a fill factor of less than 10%. We use a bilayer of Ti/Au to make the effective impedance of the absorber match the impedance of the incoming radiation for each band. Measurements of the response time of the metallized absorbers to heat pulses show that their heat capacity exceeds the predictions of the Debye model. Our results are suggestive that the surface of the low pressure chemical vapor deposition (LPCVD) Si(x)N(y) used in the absorbers' construction is the source of microstates that dominate the heat capacity.

  18. A titanium transition-edge sensor for the in-situ detection of individual He2 excimers in superfluid helium

    Science.gov (United States)

    Carter, Faustin; Hertel, Scott; Matulis, Catherine; Rooks, Michael; McKinsey, Daniel; Prober, Daniel

    2015-03-01

    Incident radiation can excite superfluid helium into a diatomic He2* excimer, which decays through the emission of a 15 eV photon. Such excimers have been used as tracers to measure the superfluid's quantum turbulence, thanks in part to the long half-life of the He2* triplet state (~ 13 seconds). However, the efficient detection of single or a few excimers remains a challenge. We present a detector capable of in-situ detection of the He2* excimers either directly (the excimer collides with the detector), or by collecting the 15 eV photon emission upon decay. This detector is based on a titanium superconducting transition-edge sensor (TES), with an energy resolution of 1.5 eV fwhm, coupled to an aluminum absorber. The TES is designed to operate from 20-300 mK in a dilution refrigerator. We will discuss operating characteristics of the detector and present preliminary data for detection of individual excimers. We acknowledge support from YINQE, NSF MRSEC DMR-1119826, and NSF DMR-1007974.

  19. Lessons from the Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available In this brief note, the implications of a condensed Sun will be examined. A celestial body composed of liquid metallic hydrogen brings great promise to astronomy, relative to understanding thermal emission and solar structure. At the same time, as an incom- pressible liquid, a condensed Sun calls into question virtually everything which is cur- rently believed with respect to the evolution and nature of the stars. Should the Sun be condensed, then neutron stars and white dwarfs will fail to reach the enormous densities they are currently believed to possess. Much of cosmology also falls into question, as the incompressibility of matter curtails any thought that a primordial atom once existed. Aging stars can no longer collapse and black holes will know no formative mechanism. A condensed Sun also hints that great strides must still be made in understanding the nature of liquids. The Sun has revealed that liquids possess a much greater potential for lattice order than previously believed. In addition, lessons may be gained with regards to the synthesis of liquid metallic hydrogen and the use of condensed matter as the basis for initiating fusion on Earth.

  20. Magnetohydrodynamics of the sun

    CERN Document Server

    Priest, Eric

    2014-01-01

    Magnetohydrodynamics of the Sun is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamics, taking account of enormous advances in understanding since that date. It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field, which is responsible for many fascinating dynamic phenomena. Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass ejections, and the acceleration of the solar wind by reconnection or wave-turbulence. It is essential reading for graduate students and researchers in solar physics and related fields of astronomy, plasma physics and fluid dynamics. Problem sets and other resources are available at www.cambridge.org/9780521854719.

  1. The Sun's Supergranulation

    CERN Document Server

    Rieutord, Michel

    2010-01-01

    The Sun's supergranulation refers to a physical pattern covering the surface of the quiet Sun with a typical horizontal scale of approximately 30000km. Its most noticeable observable signature is as a fluctuating velocity field whose components are mostly horizontal. Supergranulation was discovered more than fifty years ago, however explaining why and how it originates still represents one of the main challenges of modern solar physics. A lot of work has been devoted to the subject over the years, but observational constraints, conceptual difficulties and numerical limitations have all concurred to prevent a detailed understanding of the supergranulation phenomenon so far. With the advent of 21st century supercomputing resources and the availability of unprecedented high-resolution observations of the Sun, the solar community has now reached a stage at which key progress can be made on this question. A unifying strategy between observations and modeling is more than ever required for this to be possible. The ...

  2. Sun, Earth and Sky

    Science.gov (United States)

    Lang, Kenneth R.

    1995-01-01

    The Sun is enveloped by a hot, tenuous million-degree corona that expands to create a continuous solar wind that sweeps past all the planets and fills the heliosphere. The solar wind is modulated by strong gusts that are initiated by powerful explosions on the Sun, including solar flares and coronal mass ejections. This dynamic, invisible outer atmosphere of the Sun is currently under observation with the soft X-ray telescope aboard the Yohkoh spacecraft, whose results are presented. We also show observations from the Ulysses spacecraft that is now passing over the solar pole, sampling the solar wind in this region for the first time. Two other spacecraft, Voyager 1 and 2, have recently detected the outer edge of the invisible heliosphere, roughly halfway to the nearest star. Magnetic solar activity, the total radiative output from the Sun, and the Earth's mean global surface temperature all vary with the 11-year sunspot cycle in which the total number of sunspots varies from a maximum to a minimum and back to a maximum again in about 11 years. The terrestrial magnetic field hollows out a protective magnetic cavity, called the magnetosphere, within the solar wind. This protection is incomplete, however, so the Sun feeds an unseen world of high-speed particles and magnetic fields that encircle the Earth in space. These particles endanger spacecraft and astronauts, and also produce terrestrial aurorae. An international flotilla of spacecraft is now sampling the weak points in this magnetic defense. Similar spacecraft have also discovered a new radiation belt, in addition to the familiar Van Allen belts, except fed by interstellar ions instead of electrons and protons from the Sun.

  3. Piece of the sun

    CERN Document Server

    Wayne, Teddy

    2015-01-01

    Our rapidly industrialising world has an insatiable hunger for energy, and conventional sources are struggling to meet demand. Oil is running out, coal is damaging our climate, many nations are abandoning nuclear, yet solar, wind and water will never be a complete replacement. The solution, says Daniel Clery in this deeply researched and revelatory book, is to be found in the original energy source: the Sun itself. There, at its centre, the fusion of 630 million tonnes of hydrogen every second generates an unfathomable amount of energy. By replicating even a tiny piece of the Sun's power

  4. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  5. The SUN S TRAVELS

    Institute of Scientific and Technical Information of China (English)

    Robert; Louis; Stevenson

    2005-01-01

    The sun is not a-bed, when I At night upon my pillow lie; Stilt round the earth his Way he takes, And morning after morning makes. White here at home, in shining day, We round the sunny garden play, Each tittle Indian sleepy - head Is being kissed and put to bed. And When at eve I rise from tea, Day dawns beyond the Atlantic Sea; And all the children in the West Are getting up and being dressed.The SUN'S TRAVELS@Robert Louis Stevenson

  6. Seasonal cycle of desert aerosols in western Africa: analysis of the coastal transition with passive and active sensors

    Directory of Open Access Journals (Sweden)

    H. Senghor

    2017-07-01

    Full Text Available The impact of desert aerosols on climate, atmospheric processes, and the environment is still debated in the scientific community. The extent of their influence remains to be determined and particularly requires a better understanding of the variability of their distribution. In this work, we studied the variability of these aerosols in western Africa using different types of satellite observations. SeaWiFS (Sea-Viewing Wide Field-of-View Sensor and OMI (Ozone Monitoring Instrument data have been used to characterize the spatial distribution of mineral aerosols from their optical and physical properties over the period 2005–2010. In particular, we focused on the variability of the transition between continental western African and the eastern Atlantic Ocean. Data provided by the lidar scrolling CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization onboard the satellite CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations for the period 2007–2013 were then used to assess the seasonal variability of the vertical distribution of desert aerosols. We first obtained a good representation of aerosol optical depth (AOD and single-scattering albedo (SSA from the satellites SeaWiFS and OMI, respectively, in comparison with AERONET estimates, both above the continent and the ocean. Dust occurrence frequency is higher in spring and boreal summer. In spring, the highest occurrences are located between the surface and 3 km above sea level, while in summer the highest occurrences are between 2 and 5 km altitude. The vertical distribution given by CALIOP also highlights an abrupt change at the coast from spring to fall with a layer of desert aerosols confined in an atmospheric layer uplifted from the surface of the ocean. This uplift of the aerosol layer above the ocean contrasts with the winter season during which mineral aerosols are confined in the atmospheric boundary layer. Radiosondes at Dakar Weather Station (17.5

  7. Seasonal cycle of desert aerosols in western Africa: analysis of the coastal transition with passive and active sensors

    Science.gov (United States)

    Senghor, Habib; Machu, Éric; Hourdin, Frédéric; Thierno Gaye, Amadou

    2017-07-01

    The impact of desert aerosols on climate, atmospheric processes, and the environment is still debated in the scientific community. The extent of their influence remains to be determined and particularly requires a better understanding of the variability of their distribution. In this work, we studied the variability of these aerosols in western Africa using different types of satellite observations. SeaWiFS (Sea-Viewing Wide Field-of-View Sensor) and OMI (Ozone Monitoring Instrument) data have been used to characterize the spatial distribution of mineral aerosols from their optical and physical properties over the period 2005-2010. In particular, we focused on the variability of the transition between continental western African and the eastern Atlantic Ocean. Data provided by the lidar scrolling CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) onboard the satellite CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations) for the period 2007-2013 were then used to assess the seasonal variability of the vertical distribution of desert aerosols. We first obtained a good representation of aerosol optical depth (AOD) and single-scattering albedo (SSA) from the satellites SeaWiFS and OMI, respectively, in comparison with AERONET estimates, both above the continent and the ocean. Dust occurrence frequency is higher in spring and boreal summer. In spring, the highest occurrences are located between the surface and 3 km above sea level, while in summer the highest occurrences are between 2 and 5 km altitude. The vertical distribution given by CALIOP also highlights an abrupt change at the coast from spring to fall with a layer of desert aerosols confined in an atmospheric layer uplifted from the surface of the ocean. This uplift of the aerosol layer above the ocean contrasts with the winter season during which mineral aerosols are confined in the atmospheric boundary layer. Radiosondes at Dakar Weather Station (17.5° W, 14.74° N) provide

  8. Design and validation of a large-format transition edge sensor array magnetic shielding system for space application

    Science.gov (United States)

    Bergen, A.; van Weers, H. J.; Bruineman, C.; Dhallé, M. M. J.; Krooshoop, H. J. G.; ter Brake, H. J. M.; Ravensberg, K.; Jackson, B. D.; Wafelbakker, C. K.

    2016-10-01

    The paper describes the development and the experimental validation of a cryogenic magnetic shielding system for transition edge sensor based space detector arrays. The system consists of an outer mu-metal shield and an inner superconducting niobium shield. First, a basic comparison is made between thin-walled mu-metal and superconducting shields, giving an off-axis expression for the field inside a cup-shaped superconductor as a function of the transverse external field. Starting from these preliminary analytical considerations, the design of an adequate and realistic shielding configuration for future space flight applications (either X-IFU [D. Barret et al., e-print arXiv:1308.6784 [astro-ph.IM] (2013)] or SAFARI [B. Jackson et al., IEEE Trans. Terahertz Sci. Technol. 2, 12 (2012)]) is described in more detail. The numerical design and verification tools (static and dynamic finite element method (FEM) models) are discussed together with their required input, i.e., the magnetic-field dependent permeability data. Next, the actual manufacturing of the shields is described, including a method to create a superconducting joint between the two superconducting shield elements that avoid flux penetration through the seam. The final part of the paper presents the experimental verification of the model predictions and the validation of the shield's performance. The shields were cooled through the superconducting transition temperature of niobium in zero applied magnetic field (<10 nT) or in a DC field with magnitude ˜100 μT, applied either along the system's symmetry axis or perpendicular to it. After cool-down, DC trapped flux profiles were measured along the shield axis with a flux-gate magnetometer and the attenuation of externally applied AC fields (100 μT, 0.1 Hz, both axial and transverse) was verified along this axis with superconducting quantum interference device magnetometers. The system's measured on-axis shielding factor is greater than 106, well exceeding

  9. Maximising the sun

    CSIR Research Space (South Africa)

    Conradie, Dirk CU

    2010-08-01

    Full Text Available South Africa is blessed with some of the best quality solar radiation in the world. In the light of this many exciting opportunities exist to utilize the sun to its full potential in the design of energy efficient buildings. Passive solar buildings...

  10. Sun Ultra 5

    CERN Multimedia

    1998-01-01

    The Sun Ultra 5 is a 64-bit personal computer based on the UltraSPARC microprocessor line at a low price. The Ultra 5 has been declined in several variants: thus, some models have a processor with less cache memory to further decrease the price of the computer.

  11. The Toboggan Sun

    NARCIS (Netherlands)

    Davidson, WPS; van der Werf, SY

    2005-01-01

    Special variants of the Novaya Zemlya effect may arise from localized temperature inversions that follow the height profile of hills or mountains. Rather than following its natural path, the rising or setting Sun may, under such circumstances, appear to slide along a distant mountain slope. We found

  12. Go Sun Smart

    Science.gov (United States)

    Scott, Michael D.; Buller, David B.; Walkosz, Barbara J.; Andersen, Peter A.; Cutter, Gary R.; Dignan, Mark B.

    2008-01-01

    This is the story of Go Sun Smart, a worksite wellness program endorsed by the North American Ski Area Association and funded by the National Cancer Institute. Between 2000 and 2002 we designed and implemented a large-scale worksite intervention at over 300 ski resorts in North America with the objective of reducing ski area employees and guests…

  13. Sun, Earth and Sky

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    This Second Edition of Sun, Earth and Sky updates the popular text by providing comprehensive accounts of the most recent discoveries made by five modern solar spacecraft during the past decade. Their instruments have used sound waves to peer deep into the Sun’s inner regions and measure the temperature of its central nuclear reactor, and extended our gaze far from the visible Sun to record energetic outbursts that threaten Earth. Breakthrough observations with the underground Sudbury Neutrino Observatory are also included, which explain the new physics of ghostly neutrinos and solve the problematic mismatch between the predicted and observed amounts of solar neutrinos. This new edition of Sun, Earth and Sky also describes our recent understanding of how the Sun’s outer atmosphere is heated to a million degrees, and just where the Sun’s continuous winds come from. As humans we are more intimately linked with our life-sustaining Sun than with any other astronomical object, and the new edition therefore p...

  14. Our Explosive Sun

    Science.gov (United States)

    Brown, D. S.

    2009-01-01

    The Sun's atmosphere is a highly structured but dynamic place, dominated by the solar magnetic field. Hot charged gas (plasma) is trapped on lines of magnetic force that can snap like an elastic band, propelling giant clouds of material out into space. A range of ground-based and space-based solar telescopes observe these eruptions, particularly…

  15. Transition metal substituted SrTiO3 perovskite oxides as promising functional materials for oxygen sensor

    Science.gov (United States)

    Misra, Sunasira

    2012-07-01

    Modern industries employ several gases as process fluids. Leakage of these gases in the operating area could lead to undesirable consequences. Even in chemical industries, which use large quantities of inert gases in confined areas, accidental leakage of these process gases would result in the reduction of oxygen partial pressure in atmospheric air. For instance, large amounts of gaseous nitrogen and argon are used in pharmaceutical industries, gas filling/bottling plants, operating area of Fast Breeder reactors, etc. Fall of concentration of oxygen in air below 17% could lead to life risk (Asphyxiation) of the working personnel that has to be checked well in advance. Further, when the leaking gas is of explosive nature, its damage potential would be very high if its concentration level in air increases beyond its lower explosive limit. Surveillance of the ambient within these industries at the critical areas and also in the environment around them for oxygen therefore becomes highly essential. Sensitive and selective gas sensors made of advanced materials are required to meet this demand of monitoring environmental pollution. The perovskite class of oxides (ABO3) is chemically stable even at high temperatures and can tolerate large levels of dopants without phase transformations. The electronic properties of this parent functional material can be tailored by adding appropriate dopants that exhibit different valence states. Aliovalent transition metal substituted SrTiO3 perovskites are good mixed ionic and electronic conductors and potential candidates for sensing oxygen at percentage level exploiting their oxygen pressure dependent electrical conductivity. This paper presents the preparation, study of electrical conductivity and oxygen-sensing characteristics of iron and cobalt substituted SrTiO3.

  16. Stars resembling the Sun

    Science.gov (United States)

    Cayrel de Strobel, G.

    This review is primarily directed to the question whether photometric solar analogues remain such when subjected to detailed spectroscopic analyses and interpreted with the help of internal stucture models. In other words, whether the physical parameters: mass, chemical composition, age (determining effective temperature and luminosity), chromospheric activity, equatorial rotation, lithium abundance, velocity fields etc., we derive from the spectral analysis of a photometric solar analogue, are really close to those of the Sun. We start from 109 photometric solar analogues extracted from different authors. The stars selected had to satisfy three conditions: i) their colour index (B-V) must be contained in the interval: Δ (B-V) = 0.59-0.69, ii) they must possess a trigonometric parallax, iii) they must have undergone a high resolution detailed spectroscopic analysis. First, this review presents photometric and spectrophotometric researches on solar analogues and recalls the pionneering work on these stars by the late Johannes Hardorp. After a brief discussion on low and high resolution spectroscopic researches, a comparison is made between effective temperatures as obtained, directly, from detailed spectral analyses and those obtained, indirectly, from different photometric relations. An interesting point in this review is the discussion on the tantalilizing value of the (B-V)solar of the Sun, and the presentation of a new reliable value of this index. A short restatement of the kinematic properties of the sample of solar analogues is also made. And, finally, the observational ( T eff, M bol) diagram, obtained with 99 of the initially presented 109 analogues, is compared to a theoretical ( T eff, M bol) diagram. This latter has been constructed with a grid of internal structure models for which, (very important for this investigation), the Sun was used as gauge. In analysing the position, with respect to the Sun, of each star we hoped to find a certain number of

  17. SCIENCE OF SUN PHOTOMETRY

    Directory of Open Access Journals (Sweden)

    Alexandru Dan Toma

    2013-07-01

    Full Text Available Typically, the total amount of gases and particles in a column of atmosphere cannot be determined from measurements just at Earth's surface, by a single measurement essentially at the bottom of the atmosphere column. Balloons, airplanes, and rockets are all used to perform direct measurements in the atmosphere at altitudes up to and beyond the stratosphere. Satellite-based instruments provide global views, but it is difficult to infer surface and column distributions from space-based measurements, so such measurements must still be supplemented by ground-based measurements. Sun photometry is an important way of probing the atmosphere from the ground to measure the effects of the atmosphere on Sun radiation crossing through the atmosphere to Earth's surface. These indirect technique provide information about the entire atmosphere above the observer, not just the atmosphere that can be sampled directly close to Earth's surface.

  18. Forward modeling of the corona of the sun and solarlike stars

    DEFF Research Database (Denmark)

    Hardi, Peter; Gudiksen, Boris V.; Nordlund, Å.

    2006-01-01

    Transition Region Lines, AB-Initio Approach; Nonequilibrium Inozation; Doppler Shifts; Emission-Lines; Quiet-Sun; Sumer Telescope; Atomic Database; Magnetic-Field; Thin Plasmas......Transition Region Lines, AB-Initio Approach; Nonequilibrium Inozation; Doppler Shifts; Emission-Lines; Quiet-Sun; Sumer Telescope; Atomic Database; Magnetic-Field; Thin Plasmas...

  19. How hot is the sun

    Institute of Scientific and Technical Information of China (English)

    刘超

    2001-01-01

    Do you know how hot thesun is? There are no solidsor liquids on the sun. Why not? The temperature onoutside the sun is more than 10, 000℃, and that at the centre is about 20, 000, 000℃.The sun is so hot that all thesolids and all the liquids havebeen turned into gases.

  20. The sun, our star

    Science.gov (United States)

    Noyes, R. W.

    Observational data, analytical models, and instrumentation used to study the sun and its evolution are detailed, and attention is given to techniques for converting solar energy to useful power on earth. The star ignited when the mutual gravitational attractions of dust and vapor in a primordial cloud in the Galaxy caused an in-rush of accelerating particles which eventually became dense enough to ignite. The heat grew until inward rushing matter was balanced by outward moving radiative forces. The planets formed from similar debris, and solar radiation is suggested to have triggered the chemical reactions giving rise to life on earth. Visual, spectroscopic, coronagraphic, and UV observations of the sun from the ground and from spacecraft, particularly Skylab, are described, together with features of the solar surface, magnetic field, sunspots, and coronal loops. Models for the processes that occur in the solar interior are explored, as are the causes of solar flares. Attention is given to solar cells, heliostat arrays, wind turbines, and water turbines as means to convert, either directly or indirectly, the earth-bound solar energy to electrical and thermal power. Finally, the life cycle of the sun, about 9 billion yr in duration, is summarized, noting the current status of midlife.

  1. X-ray microanalysis with transition edge sensors. The future of material analysis with scanning electron microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Hollerith, C.

    2006-07-05

    In current experiments and technical applications the demand for new and advanced concepts for the detection of radiation and particle is increasing. Low temperature detectors such as Transition Edge Sensors (TES) have been developed as ultrahigh-resolution radiation and particle detectors offering advantages in manifold applications. They were designed primarily for astrophysical experiments such as the dark matter search. In material analysis they have been introduced to revolutionize mass spectroscopy of biological molecules and Energy Dispersive X-ray Spectroscopy (EDS). EDS is the determination of the elemental constitution of samples in scanning electron microscopes (SEMs) with characteristic X-ray radiation excited by the electron beam. The use of TES detectors improves the EDS analysis of small volumes such as particles or thin layers. This is especially important for the semiconductor industry because of the continual shrinking of device size. Current structure sizes of 65 nm are already demanding new approaches in analytic methodology. In this thesis the introduction and improvement of a fully automated TES detector system in the industrial environment of a semiconductor failure analysis lab is described. This system, marketed under the trade name of 'Polaris' by the manufacturer, is based on a mechanical pulse tube cooler in combination with an adiabatic demagnetization refrigerator (ADR) for cooling the TES detector to its operating temperature. Several large improvements had to be made to the system during the total system integration. The energy resolution could be improved significantly thus enabling a better peak separation and the measurement of chemical shifts. Due to the small area of TES detectors compared with conventional EDS detectors the efficiency of the system proved to be too low for everyday use. A polycapillary X-ray lens was added to the system in order to solve this problem. The application of the lens, however, brought its

  2. Development of the Next Generation of Multi-chroic Antenna-Coupled Transition Edge Sensor Detectors for CMB Polarimetry

    Science.gov (United States)

    Westbrook, B.; Cukierman, A.; Lee, A.; Suzuki, A.; Raum, C.; Holzapfel, W.

    2016-07-01

    We present the development of the next generation of multi-chroic sinuous antenna-coupled transition edge sensor (TES) bolometers optimized for precision measurements of polarization of the cosmic microwave background (CMB) and cosmic foreground. These devices employ a polarization sensitive broadband self-complementary sinuous antenna to feed on-chip band defining filters before delivering the power to load resistors coupled to a TES on a released bolometer island. This technology was originally developed by UC Berkeley and will be deployed by POLARBEAR-2 and SPT-3G in the next year and half. In addition, it is a candidate detector for the LiteBIRD mission which will make all sky CMB and cosmic foreground polarization observations from a satellite platform in the early 2020's. This works focuses on expanding both the bandwidth and band count per pixel of this technology in order to meet the needs of future CMB missions. This work demonstrates that these devices are well suited for observations between 20 and 380 GHz. This proceeding describes the design, fabrication, and the characterization of three new pixel types: a low-frequency triplexing pixel (LFTP) with bands centered on 40, 60, and 90 GHz, a high-frequency triplexing pixel (HFTP) with bands centered on 220, 280, and 350 GHz, and a mid-frequency tetraplexing pixel with bands (MFTP) centered on 90, 150, 220, and 280 GHz. The average fractional bandwidth of these pixels designs was 36.7, 34.5, and 31.4 % respectively. In addition we found that the polarization modulation efficiency of each band was between 1 and 3 % which is consistent with the polarization efficiency of the wire grid used to take the measurement. Finally, we find that the beams have {˜ }1 % ellipticity for each pixel type. The thermal properties of the bolometers where tuned for characterization in our lab so we do not report on G and noise values as they would be unsuitable for modern CMB experiments.

  3. A High-Speed Target-Free Vision-Based Sensor for Bus Rapid Transit Viaduct Vibration Measurements Using CMT and ORB Algorithms

    Directory of Open Access Journals (Sweden)

    Qijun Hu

    2017-06-01

    Full Text Available Bus Rapid Transit (BRT has become an increasing source of concern for public transportation of modern cities. Traditional contact sensing techniques during the process of health monitoring of BRT viaducts cannot overcome the deficiency that the normal free-flow of traffic would be blocked. Advances in computer vision technology provide a new line of thought for solving this problem. In this study, a high-speed target-free vision-based sensor is proposed to measure the vibration of structures without interrupting traffic. An improved keypoints matching algorithm based on consensus-based matching and tracking (CMT object tracking algorithm is adopted and further developed together with oriented brief (ORB keypoints detection algorithm for practicable and effective tracking of objects. Moreover, by synthesizing the existing scaling factor calculation methods, more rational approaches to reducing errors are implemented. The performance of the vision-based sensor is evaluated through a series of laboratory tests. Experimental tests with different target types, frequencies, amplitudes and motion patterns are conducted. The performance of the method is satisfactory, which indicates that the vision sensor can extract accurate structure vibration signals by tracking either artificial or natural targets. Field tests further demonstrate that the vision sensor is both practicable and reliable.

  4. Differences in Trunk Accelerometry Between Frail and Nonfrail Elderly Persons in Sit-to-Stand and Stand-to-Sit Transitions Based on a Mobile Inertial Sensor.

    Science.gov (United States)

    Galán-Mercant, Alejandro; Cuesta-Vargas, Antonio I

    2013-08-16

    Clinical frailty syndrome is a common geriatric syndrome, which is characterized by physiological reserve decreases and increased vulnerability. The changes associated to ageing and frailties are associated to changes in gait characteristics and the basic functional capacities. Traditional clinical evaluation of Sit-to-Stand (Si-St) and Stand-to-Sit (St-Si) transition is based on visual observation of joint angle motion to describe alterations in coordination and movement pattern. The latest generation smartphones often include inertial sensors with subunits such as accelerometers and gyroscopes, which can detect acceleration. Firstly, to describe the variability of the accelerations, angular velocity, and displacement of the trunk during the Sit-to-Stand and Stand-to-Sit transitions in two groups of frail and physically active elderly persons, through instrumentation with the iPhone 4 smartphone. Secondly, we want to analyze the differences between the two study groups. A cross-sectional study that involved 30 subjects over 65 years, 14 frail and 16 fit subjects. The participants were classified with frail syndrome by the Fried criteria. Linear acceleration was measured along three orthogonal axes using the iPhone 4 accelerometer. Each subject performed up to three successive Si-St and St-Si postural transitions using a standard chair with armrest. Significant differences were found between the two groups of frail and fit elderly persons in the accelerometry and angular displacement variables obtained in the kinematic readings of the trunk during both transitions. The inertial sensor fitted in the iPhone 4 is able to study and analyze the kinematics of the Si-St and St-Si transitions in frail and physically active elderly persons. The accelerometry values for the frail elderly are lower than for the physically active elderly, while variability in the readings for the frail elderly is also lower than for the control group.

  5. The Sun in Time: Activity and Environment

    CERN Document Server

    Güdel, M

    2007-01-01

    (abridged) The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels, its faster rotation generated enhanced magnetic activity; magnetic heating processes in the chromosphere, the transition region, and the corona induced ultraviolet, extreme-ultraviolet, and X-ray emission about 10, 100, and 1000 times, respectively, the present-day levels, as inferred from young solar-analog stars. Also, the production rate of accelerated, high-energy particles was orders of magnitude higher than in present-day solar flares, and a much stronger wind escaped from the Sun, permeating the entire solar system. The consequences of the enhanced radiation and particle fluxes from the young Sun were potentially severe for the evolution of solar-system planets and moons. Interactions of high-energy radiation and the solar wind with upper planetary atmospheres may have...

  6. The Sun in Time: Activity and Environment

    Directory of Open Access Journals (Sweden)

    Güdel Manuel

    2007-12-01

    Full Text Available The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels, its faster rotation generated enhanced magnetic activity; magnetic heating processes in the chromosphere, the transition region, and the corona induced ultraviolet, extreme-ultraviolet, and X-ray emission about 10, 100, and 1000 times, respectively, the present-day levels, as inferred from young solar-analog stars. Also, the production rate of accelerated, high-energy particles was orders of magnitude higher than in present-day solar flares, and a much stronger wind escaped from the Sun, permeating the entire solar system. The consequences of the enhanced radiation and particle fluxes from the young Sun were potentially severe for the evolution of solar-system planets and moons. Interactions of high-energy radiation and the solar wind with upper planetary atmospheres may have led to the escape of important amounts of atmospheric constituents. The present dry atmosphere of Venus and the thin atmosphere of Mars may be a product of early irradiation and heating by solar high-energy radiation. High levels of magnetic activity are also inferred for the pre-main sequence Sun. At those stages, interactions of high-energy radiation and particles with the circumsolar disk in which planets eventually formed were important. Traces left in meteorites by energetic particles and anomalous isotopic abundance ratios in meteoritic inclusions may provide evidence for a highly active pre-main sequence Sun. The present article reviews these various issues related to the magnetic activity of the young Sun and the consequent interactions with its environment. The emphasis is on the phenomenology related to the production of high-energy photons and particles. Apart from the activity on the young Sun, systematic trends applicable to the entire

  7. Review - The Sun Rises

    Directory of Open Access Journals (Sweden)

    Mark Bender

    2012-12-01

    Full Text Available Review of: Blackburn, Stuart H. 2010. The Sun Rises: A Shaman's Chant, Ritual Exchange and Fertility in the Apatani Valley. Leiden: Brill. xvii+401. Color and black and white photographs, maps. ISBN: 9789-0041-7578-5 (hardcover, 97USD. The Sun Rises is a model study contextualizing an oral narrative tradition in the social and ritual fabric of a remote community in northeast India. In many ways a companion volume to Himalayan Tribal Tales (Blackburn 2008, the text presents the first substantial translation of a key ritual text of the Apantani Valley dwellers in Arunachal Pradesh, located on the contested border between China (Tibet and India. The Apatani speak a Tibeto-Burman language, practice intensive rice agriculture in carefully terraced fields, and number about 35,000. Their clans populate several centuries-old villages. Until recently, they were separated from the lowlands of Assam and surrounded only by peoples practicing various forms of shifting agriculture. The valley dwellers have increasingly encountered modernization over the last few decades, including Indian and global popular culture, and Christianity. The heart of this book is a chant of nineteen segments.

  8. Sit-stand and stand-sit transitions in older adults and patients with Parkinson's disease: event detection based on motion sensors versus force plates.

    Science.gov (United States)

    Zijlstra, Agnes; Mancini, Martina; Lindemann, Ulrich; Chiari, Lorenzo; Zijlstra, Wiebren

    2012-10-07

    Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as seat on/off in the sensor-based data. Therefore, the aim of this study was to evaluate the agreement of detecting sit-stand and stand-sit events based on a novel body-fixed-sensor method with a force-plate based analysis. Twelve older adults and 10 patients with mild to moderate Parkinson's disease with mean age of 70 years performed sit-stand-sit movements while trunk movements were measured with a sensor-unit at vertebrae L2-L4 and reaction forces were measured with separate force plates below the feet and chair. Movement onsets and ends were determined. In addition, seat off and seat on were determined based on forces acting on the chair. Data analysis focused on the agreement of the timing of sit-stand and stand-sit events as detected by the two methods. For the start and end of standing-up, only small delays existed for the start of forward trunk rotation and end of backward trunk rotation compared to movement onset/end as detected in the force-plate data. The end of forward trunk rotation had a small and consistent delay compared to seat off, whereas during sitting-down, the end of forward trunk rotation occurred earlier in relation to seat on. In detecting the end of sitting-down, backward trunk rotation ended after reaching the minimum in the below-feet vertical force signal. Since only small time differences existed between the two methods for detecting the start of sitting-down, longer movement durations were found for the sensor-based method. Relative agreement between the two methods in assessing movement duration was high (i.e. ICCs ≥ 0.75), except for duration of standing-up in the Parkinson's patients (ICC = 0.61). This study demonstrated high agreement of

  9. Sit-stand and stand-sit transitions in older adults and patients with Parkinson’s disease: event detection based on motion sensors versus force plates

    Science.gov (United States)

    2012-01-01

    Background Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as seat on/off in the sensor-based data. Therefore, the aim of this study was to evaluate the agreement of detecting sit-stand and stand-sit events based on a novel body-fixed-sensor method with a force-plate based analysis. Methods Twelve older adults and 10 patients with mild to moderate Parkinson’s disease with mean age of 70 years performed sit-stand-sit movements while trunk movements were measured with a sensor-unit at vertebrae L2-L4 and reaction forces were measured with separate force plates below the feet and chair. Movement onsets and ends were determined. In addition, seat off and seat on were determined based on forces acting on the chair. Data analysis focused on the agreement of the timing of sit-stand and stand-sit events as detected by the two methods. Results For the start and end of standing-up, only small delays existed for the start of forward trunk rotation and end of backward trunk rotation compared to movement onset/end as detected in the force-plate data. The end of forward trunk rotation had a small and consistent delay compared to seat off, whereas during sitting-down, the end of forward trunk rotation occurred earlier in relation to seat on. In detecting the end of sitting-down, backward trunk rotation ended after reaching the minimum in the below-feet vertical force signal. Since only small time differences existed between the two methods for detecting the start of sitting-down, longer movement durations were found for the sensor-based method. Relative agreement between the two methods in assessing movement duration was high (i.e. ICCs ≥ 0.75), except for duration of standing-up in the Parkinson’s patients (ICC = 0.61). Conclusions

  10. Kinematic parameters to evaluate functional performance of sit-to-stand and stand-to-sit transitions using motion sensor devices: a systematic review.

    Science.gov (United States)

    Millor, Nora; Lecumberri, Pablo; Gomez, Marisol; Martinez-Ramirez, Alicia; Izquierdo, Mikel

    2014-09-01

    Clinicians commonly use questionnaires and tests based on daily life activities to evaluate physical function. However, the outcomes are usually more qualitative than quantitative and subtle differences are not detectable. In this review, we aim to assess the role of body motion sensors in physical performance evaluation, especially for the sit-to-stand and stand-to-sit transitions. In total, 53 full papers and conference abstracts on related topics were included and 16 different parameters related to transition performance were identified as potentially meaningful to explain certain disabilities and impairments. Transition duration is the most used to evaluate chair-related tests in real clinical settings. High-fall-risk fallers and frail subjects presented longer and more variable transition duration. Other kinematic parameters have also been highlighted in the literature as potential means to detect age-related impairments. In particular, vertical linear velocity and trunk tilt range were able to differentiate between different frailty levels. Frequency domain measures such as spectral edge frequency were also higher for elderly fallers. Lastly, approximate entropy values were larger for subjects with Parkinson's disease and were significantly reduced after treatment. This information could help clinicians in their evaluations as well as in prescribing a physical fitness program to correct a specific deficit.

  11. Eruptions from the Sun

    Science.gov (United States)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  12. A Fabrication Route for Arrays of Ultra-low-Noise MoAu Transition Edge Sensors on Thin Silicon Nitride for Space Applications

    CERN Document Server

    Glowacka, D M; Goldie, D J; Withington, S

    2014-01-01

    We describe a process route to fabricate arrays of Ultra-low-Noise MoAu Transition Edge Sensors (TESs). The low thermal conductance required for space applications is achieved using 200 nm-thick Silicon Nitride (SiNx ) patterned to form long-thin legs with widths of 2.1 {\\mu}m. Using bilayers formed on SiNx islands from films with 40 nm-thick Mo and Au thicknesses in the range 30 to 280 nm deposited by dc-sputtering in ultra-high vacuum we can obtain tunable transition temperatures in the range 700 to 70 mK. The sensors use large-area absorbers fabricated from high resistivity, thin-film beta-phase Ta to provide impedance-matching to incident radiation. The absorbers are patterned to reduce the heat capacity associated with the nitride support structure and include Au thermalizing features to assist the heat flow into the TES. Arrays of 400 detectors at the pixel spacing required for the long-wavelength band of the far-infrared instrument SAFARI are now being fabricated. Device yields approaching 99% are achi...

  13. The validated sun exposure questionnaire

    DEFF Research Database (Denmark)

    Køster, B; Søndergaard, J; Nielsen, J B

    2017-01-01

    Few questionnaires used in monitoring sun-related behavior have been tested for validity. We established criteria validity of a developed questionnaire for monitoring population sun-related behavior. During May-August 2013, 664 Danes wore a personal electronic UV-dosimeter for one week...... that measured the outdoor time and dose of erythemal UVR exposure. In the following week, they answered a questionnaire on their sun-related behavior in the measurement week. Outdoor time measured by dosimetry correlated strongly with both outdoor time and the developed exposure scale measured....... The weekly sunburn fraction correlated strongly with the number of ambient sun hours (r=0.73, p

  14. The Sun, Mercury, and Venus

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    The Messenger mission to Mercury opened a new window into the inner solar system. In 2008, this mission began a number of years of flybys, culminating in an orbital insertion around Mercury and producing unparalleled observations about this mysterious innermost planet. Mercury orbits so close to the Sun, from the point of view of Earth, that seeing it from the Earth against the Sun's glare is a great challenge. At the same time, the huge gravitational force of the Sun makes it a challenge to put a mission on Mercury without losing it into the Sun. Now, with heightened understanding of Mercury,

  15. The Rapidly Rotating Sun

    Science.gov (United States)

    Hanasoge, Shravan M.; Duvall, Thomas L., Jr.; Sreenivasan, Katepalli R.

    2012-01-01

    Convection in the solar interior is thought to comprise structures at a continuum of scales, from large to small. This conclusion emerges from phenomenological studies and numerical simulations though neither covers the proper range of dynamical parameters of solar convection. In the present work, imaging techniques of time-distance helioseismology applied to observational data reveal no long-range order in the convective motion. We conservatively bound the associated velocity magnitudes, as a function of depth and the spherical-harmonic degree l to be 20-100 times weaker than prevailing estimates within the wavenumber band l ux of a solar luminosity outwards? The Sun is seemingly a much faster rotator than previously thought, with advection dominated by Coriolis forces at scales l < 60.

  16. Sun light European Project

    Science.gov (United States)

    Soubielle, Marie-Laure

    2015-04-01

    2015 has been declared the year of light. Sunlight plays a major role in the world. From the sunbeams that heat our planet and feed our plants to the optical analysis of the sun or the modern use of sun particles in technologies, sunlight is everywhere and it is vital. This project aims to understand better the light of the Sun in a variety of fields. The experiments are carried out by students aged 15 to 20 in order to share their discoveries with Italian students from primary and secondary schools. The experiments will also be presented to a group of Danish students visiting our school in January. All experiments are carried out in English and involve teams of teachers. This project is 3 folds: part 1: Biological project = what are the mechanisms of photosynthesis? part 2: Optical project= what are the components of sunlight and how to use it? part 3: Technical project= how to use the energy of sunlight for modern devices? Photosynthesis project Biology and English Context:Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can later fuel the organisms' activities. This chemical energy is stored in molecules which are synthesized from carbon dioxide and water. In most cases, oxygen is released as a waste product. Most plants perform photosynthesis. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth. Outcome: Our project consists in understanding the various steps of photosynthesis. Students will shoot a DVD of the experiments presenting the equipments required, the steps of the experiments and the results they have obtained for a better understanding of photosynthesis Digital pen project Electricity, Optics and English Context: Sunlight is a complex source of light based on white light that can be decomposed to explain light radiations or colours. This light is a precious source to create

  17. Physics of the sun

    CERN Document Server

    Holzer, Thomas; Mihalas, Dimitri; Ulrich, Roger

    1986-01-01

    This volume, together with its two companion volumes, originated in a study commis­ sioned by the United States National Academy of Sciences on behalf of the National Aeronautics and Space Administration. A committee composed of Tom Holzer, Dimitri Mihalas, Roger Ulrich and myself was asked to prepare a comprehensive review of current knowledge concerning the physics of the sun. We were fortunate in being able to persuade many distinguished scientists to gather their forces for the preparation of 21 separate chapters covering not only solar physics but also relevant areas of astrophysics and solar-terrestrial relations. It proved necessary to divide the chapters into three separate volumes that cover three different aspects of solar physics. Volumes 1 and 2 are concerned with 'The Solar Interior' and with 'The Solar Atmosphere'. This volume, devoted to 'Astrophysics and Solar-Terrestrial Relations', focuses on problems of solar physics from these two different but complementary perspectives. The emphasis thr...

  18. Why the sun sucks - Architects versus the sun

    NARCIS (Netherlands)

    De Lange, N.; Niesten, J.; Taminiau, P.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will show how not to design with the Sun. By showing examples how buildings have failed that have not taken the Sun and its effects in consideration, one should get a clearer picture of how you

  19. Why the sun sucks - Architects versus the sun

    NARCIS (Netherlands)

    De Lange, N.; Niesten, J.; Taminiau, P.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will show how not to design with the Sun. By showing examples how buildings have failed that have not taken the Sun and its effects in consideration, one should get a clearer picture of how you

  20. Small satellite attitude control for sun-oriented operations utilizing a momentum bias with magnetic actuators

    Science.gov (United States)

    Wolfe, Scott M.

    1995-03-01

    The feasibility of using a three axis control, momentum bias system with magnetic actuators for sun-oriented operations is explored. Relevant equations of motion are developed for a sun-oriented coordinate system and control laws are developed for initial spacecraft capture after launch vehicle separation; reorientation from Earth oriented to a sun oriented operations mode; sun-oriented attitude control; and momentum wheel control. Simulations demonstrating the stability and time responsiveness of the system are performed. Sensor noise input tests are performed to investigate the systems susceptibility to imperfect conditions. Cross product of inertia effects are also input to test for system instability.

  1. Smart, passive sun facing surfaces

    Science.gov (United States)

    Hively, Lee M.

    1996-01-01

    An article adapted for selectively utilizing solar radiation comprises an absorptive surface and a reflective surface, the absorptive surface and the reflective surface oriented to absorb solar radiation when the sun is in a relatively low position, and to reflect solar radiation when the sun is in a relatively high position.

  2. Global Seismology of the Sun

    CERN Document Server

    Basu, Sarbani

    2016-01-01

    The seismic study of the Sun and other stars offers a unique window into the interior of these stars. Thanks to helioseismology, we know the structure of the Sun to admirable precision. In fact, our knowledge is good enough to use the Sun as a laboratory. We have also been able to study the dynamics of the Sun in great detail. Helioseismic data also allow us to probe the changes that take place in the Sun as solar activity waxes and wanes. The seismic study of stars other than the Sun is a fairly new endeavour, but we are making great strides in this field. In this review I discuss some of the techniques used in helioseismic analyses and the results obtained using those techniques. In this review I focus on results obtained with global helioseismology, i.e., the study of the Sun using its normal modes of oscillation. I also briefly touch upon asteroseismology, the seismic study of stars other than the Sun, and discuss how seismic data of others stars are interpreted.

  3. The Sun: the Earth light source

    Science.gov (United States)

    Berrilli, Francesco; Giovannelli, Luca; Del Moro, Dario; Piazzesi, Roberto; Catena, Liu` Maria; Amicucci, Giordano; Vittorio, Nicola

    2015-04-01

    We have implemented at Department of Physics of University of Rome Tor Vergata a project called "The Sun: the Earth light source". The project obtained the official endorsement from the IAU Executive Committee Working Group for the International Year of Light. The project, specifically designed for high school students, is focused on the "scientific" study of Sun light by means of a complete acquisition system based on "on the shelf" appropriately CMOS low-cost sensor with free control s/w and self-assembled telescopes. The project (hereafter stage) plan is based on a course of two weeks (60 hours in total). The course contains 20 hours of theoretical lectures, necessary to learn basics about Sun, optics, telescopes and image sensors, and 40 hours of laboratory. During the course, scientists and astronomers share with high schools students, work activities in real research laboratories. High schools teachers are intensely involved in the project. Their role is to share activities with university teachers and realize outreach actions in the home institutions. Simultaneously, they are introduced to innovative teaching methods and the project in this way is regarded as a professional development course. Sun light analysis and Sun-Earth connection through light are the main scientific topics of this project. The laboratory section of the stage is executed in two phases (weeks): First phase aims are the realization of a keplerian telescope and low-cost acquisition system. During this week students are introduced to astronomical techniques used to safety collect and acquire solar light; Second phase aims is the realization of a low-cost instrument to analyse sunlight extracting information about the solar spectrum, solar irradiance and Sun-Earth connection. The proposed stage has been already tested in Italy reached the fifth edition in 2014. Since 2010, the project has been a cornerstone outreach program of the University of Rome Tor Vergata, the Italian Ministry of

  4. Reconnection on the Sun

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    Because the Sun is so close, it makes an excellent laboratory to study processes we cant examinein distant stars. One openquestion is that of how solar magnetic fields rearrange themselves, producing the tremendous releases of energy we observe as solar flares and coronal mass ejections (CMEs).What is Magnetic Reconnection?Magnetic reconnection occurs when a magnetic field rearranges itself to move to a lower-energy state. As field lines of opposite polarity reconnect, magnetic energy is suddenly converted into thermal and kinetic energy.This processis believed to be behind the sudden releases of energy from the solar surface in the form of solar flares and CMEs. But there are many different models for how magnetic reconnection could occur in the magnetic field at the Suns surface, and we arent sure which one of these reconnection types is responsible for the events we see.Recently, however, several studies have been published presenting some of the first observational support of specific reconnection models. Taken together, these observations suggest that there are likely several different types of reconnection happening on the solar surface. Heres a closer look at two of these recent publications:A pre-eruption SDO image of a flaring region (b) looks remarkably similar to a 3D cartoon for typical breakout configuration (a). Click for a closer look! [Adapted from Chen et al. 2016]Study 1:Magnetic BreakoutLed by Yao Chen (Shandong University in China), a team of scientists has presented observations made by the Solar Dynamics Observatory (SDO) of a flare and CME event that appears to have been caused by magnetic breakout.In the magnetic breakout model, a series of loops in the Suns lower corona are confined by a surrounding larger loop structure called an arcade higher in the corona. As the lower loops push upward, reconnection occurs in the upper corona, removing the overlying, confining arcade. Without that extra confinement, the lower coronal loops expand upward

  5. Totality eclipses of the Sun

    CERN Document Server

    Littmann, Mark; Willcox, Ken

    2008-01-01

    A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. - ;A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. Totality: Eclipses of the Sun is the best guide and reference book on solar eclipses ever written. It explains: how to observe them; how to photograph and videotape them; why they occur; their history and mythology; and future eclipses - when and where to see them. Totality also tells the remarkable story of how eclipses shocked scientists, revealed the workings of the Sun, and made Einstein famous. And the book shares the experiences and advice of many veteran eclipse observers. Totality: Eclipses of the Sun is profusely ill...

  6. Measurement of the 240Pu/239Pu mass ratio using a transition-edge-sensor microcalorimeter for total decay energy spectroscopy.

    Science.gov (United States)

    Hoover, Andrew S; Bond, Evelyn M; Croce, Mark P; Holesinger, Terry G; Kunde, Gerd J; Rabin, Michael W; Wolfsberg, Laura E; Bennett, Douglas A; Hays-Wehle, James P; Schmidt, Dan R; Swetz, Daniel; Ullom, Joel N

    2015-04-07

    We have developed a new category of sensor for measurement of the (240)Pu/(239)Pu mass ratio from aqueous solution samples with advantages over existing methods. Aqueous solution plutonium samples were evaporated and encapsulated inside of a gold foil absorber, and a superconducting transition-edge-sensor microcalorimeter detector was used to measure the total reaction energy (Q-value) of nuclear decays via heat generated when the energy is thermalized. Since all of the decay energy is contained in the absorber, we measure a single spectral peak for each isotope, resulting in a simple spectral analysis problem with minimal peak overlap. We found that mechanical kneading of the absorber dramatically improves spectral quality by reducing the size of radioactive inclusions within the absorber to scales below 50 nm such that decay products primarily interact with atoms of the host material. Due to the low noise performance of the microcalorimeter detector, energy resolution values of 1 keV fwhm (full width at half-maximum) at 5.5 MeV have been achieved, an order of magnitude improvement over α-spectroscopy with conventional silicon detectors. We measured the (240)Pu/(239)Pu mass ratio of two samples and confirmed the results by comparison to mass spectrometry values. These results have implications for future measurements of trace samples of nuclear material.

  7. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Patient Stories Español Eye Health / Tips & Prevention Your Eyes and the Sun Sections The Sun, UV Radiation ... Safety Infographic The Sun, UV Radiation and Your Eyes Written by: David Turbert Aug. 28, 2014 Keep ...

  8. Clustering of Sun Exposure Measurements

    DEFF Research Database (Denmark)

    Have, Anna Szynkowiak; Larsen, Jan; Hansen, Lars Kai

    2002-01-01

    In a medically motivated Sun-exposure study, questionnaires concerning Sun-habits were collected from a number of subjects together with UV radiation measurements. This paper focuses on identifying clusters in the heterogeneous set of data for the purpose of understanding possible relations between...... Sun-habits exposure and eventually assessing the risk of skin cancer. A general probabilistic framework originally developed for text and Web mining is demonstrated to be useful for clustering of behavioral data. The framework combines principal component subspace projection with probabilistic...

  9. Skylab Apollo Telescope Mount Spar and Sun End

    Science.gov (United States)

    1971-01-01

    The Apollo Telescope Mount (ATM) was designed and developed by the Marshall Space Flight Center and served as the primary scientific instrument unit aboard Skylab (1973-1979). The ATM contained eight complex astronomical instruments designed to observe the Sun over a wide spectrum from visible light to x-rays. This image depicts the sun end and spar of the ATM flight unit showing individual telescopes. All solar telescopes, the fine Sun sensors, and some auxiliary systems are mounted on the spar, a cruciform lightweight perforated metal mounting panel that divides the canister lengthwise into four equal compartments. The spar assembly was nested inside a cylindrical canister that fit into a complex frame named the rack, and was protected by the solar shield.

  10. Prototype of sun projector device

    Science.gov (United States)

    Ihsan; Dermawan, B.

    2016-11-01

    One way to introduce astronomy to public, including students, can be handled by solar observation. The widely held device for this purpose is coelostat and heliostat. Besides using filter attached to a device such as telescope, it is safest to use indirect way for observing the Sun. The main principle of the indirect way is deflecting the sun light and projecting image of the sun on a screen. We design and build a simple and low-cost astronomical device, serving as a supplement to increase public service, especially for solar observation. Without using any digital and intricate supporting equipment, people can watch and relish image of the Sun in comfortable condition, i.e. in a sheltered or shady place. Here we describe a design and features of our prototype of the device, which still, of course, has some limitations. In the future, this prototype can be improved for more efficient and useful applications.

  11. NEW SUNS IN THE COSMOS?

    Energy Technology Data Exchange (ETDEWEB)

    De Freitas, D. B.; Leao, I. C.; Lopes, C. E. Ferreira; Paz-Chinchon, F.; Canto Martins, B. L.; Alves, S.; De Medeiros, J. R. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Catelan, M. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago (Chile)

    2013-08-20

    The present work reports on the discovery of three stars that we have identified to be rotating Sun-like stars, based on rotational modulation signatures inferred from light curves from the CoRoT mission's Public Archives. In our analysis, we performed an initial selection based on the rotation period and position in the period-T{sub eff} diagram. This revealed that the stars CoRoT IDs 100746852, 102709980, and 105693572 provide potentially good matches to the Sun with a similar rotation period. To refine our analysis, we applied a novel procedure, taking into account the fluctuations of the features associated with photometric modulation at different time intervals and the fractality traces that are present in the light curves of the Sun and of these ''New Sun'' candidates alike. In this sense, we computed the so-called Hurst exponent for the referred stars, for a sample of 14 CoRoT stars with sub- and super-solar rotational periods, and for the Sun itself in its active and quiet phases. We found that the Hurst exponent can provide a strong discriminant of Sun-like behavior, going beyond what can be achieved with solely the rotation period itself. In particular, we find that CoRoT ID 105693572 is the star that most closely matches the solar rotation properties as far as the latter's imprints on light curve behavior are concerned. The stars CoRoT IDs 100746852 and 102709980 have significant smaller Hurst exponents than the Sun, notwithstanding their similarity in rotation periods.

  12. M-DNA/Transition Metal Dichalcogenide Hybrid Structure-based Bio-FET sensor with Ultra-high Sensitivity

    Science.gov (United States)

    Park, Hyung-Youl; Dugasani, Sreekantha Reddy; Kang, Dong-Ho; Yoo, Gwangwe; Kim, Jinok; Gnapareddy, Bramaramba; Jeon, Jaeho; Kim, Minwoo; Song, Young Jae; Lee, Sungjoo; Heo, Jonggon; Jeon, Young Jin; Park, Sung Ha; Park, Jin-Hong

    2016-01-01

    Here, we report a high performance biosensor based on (i) a Cu2+-DNA/MoS2 hybrid structure and (ii) a field effect transistor, which we refer to as a bio-FET, presenting a high sensitivity of 1.7 × 103 A/A. This high sensitivity was achieved by using a DNA nanostructure with copper ions (Cu2+) that induced a positive polarity in the DNA (receptor). This strategy improved the detecting ability for doxorubicin-like molecules (target) that have a negative polarity. Very short distance between the biomolecules and the sensor surface was obtained without using a dielectric layer, contributing to the high sensitivity. We first investigated the effect of doxorubicin on DNA/MoS2 and Cu2+-DNA/MoS2 nanostructures using Raman spectroscopy and Kelvin force probe microscopy. Then, we analyzed the sensing mechanism and performance in DNA/MoS2- and Cu2+-DNA/MoS2-based bio-FETs by electrical measurements (ID-VG at various VD) for various concentrations of doxorubicin. Finally, successful operation of the Cu2+-DNA/MoS2 bio-FET was demonstrated for six cycles (each cycle consisted of four steps: 2 preparation steps, a sensing step, and an erasing step) with different doxorubicin concentrations. The bio-FET showed excellent reusability, which has not been achieved previously in 2D biosensors. PMID:27775004

  13. SunShot Initiative Portfolio Book 2014

    Energy Technology Data Exchange (ETDEWEB)

    Solar Energy Technologies Office

    2014-05-01

    The 2014 SunShot Initiative Portfolio Book outlines the progress towards the goals outlined in the SunShot Vision Study. Contents include overviews of each of SunShot’s five subprogram areas, as well as a description of every active project in the SunShot’s project portfolio as of May 2014.

  14. Magnetic Patches in Internetwork Quiet Sun

    Science.gov (United States)

    De Wijn, Alfred; Lites, B.; Berger, T.; Shine, R.; Title, A.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Hinode Team

    2007-05-01

    We study strong flux elements in the quiet sun in the context of the nature of quiet-sun magnetism, its coupling to chromospheric, transition-region and coronal fields, and the nature of a local turbulent dynamo. Strong, kilogauss flux elements show up intermittently as small bright points in G-band and Ca II H images. Although bright points have been extensively studied in the magnetic network, internetwork magnetism has only come under scrutiny in recent years. A full spectrum of field strengths seems to be ubiquitously present in the internetwork at small spatial scales, with the stronger elements residing in intergranular lanes. De Wijn et al. (2005) found that bright points in quiet sun internetwork areas appear recurrently with varying intensity and horizontal motion within long-lived patches that outline cell patterns on mesogranular scales. They estimate that the "magnetic patches" have a mean lifetime of nine hours, much longer than granular timescales. We use multi-hour sequences of G-band and Ca II H images as well as magnetograms recorded by the Hinode satellite to follow up on their results. The larger field of view, the longer sequences, the addition of magnetograms, and the absence of atmospheric seeing allows us to better constrain the patch lifetime, to provide much improved statistics on IBP lifetime, to compare IBPs to network bright points, and to study field polarity of IBPs in patches and between nearby patches. Hinode is an international project supported by JAXA, NASA, PPARC and ESA. We are grateful to the Hinode team for all their efforts in the design, build and operation of the mission.

  15. Earth's Heat Source - The Sun

    CERN Document Server

    Manuel, Oliver K

    2009-01-01

    The Sun encompasses planet Earth, supplies the heat that warms it, and even shakes it. The United Nation Intergovernmental Panel on Climate Change (IPCC) assumed that solar influence on our climate is limited to changes in solar irradiance and adopted the consensus opinion of a Hydrogen-filled Sun, the Standard Solar Model (SSM). They did not consider the alternative solar model and instead adopted another consensus opinion: Anthropogenic greenhouse gases play a dominant role in climate change. The SSM fails to explain the solar wind, solar cycles, and the empirical link of solar surface activity with Earth changing climate. The alternative solar model, that was molded from an embarrassingly large number of unexpected observations revealed by space-age measurements since 1959, explains not only these puzzles but also how closely linked interactions between the Sun and its planets and other celestial bodies induce turbulent cycles of secondary solar characteristics that significantly affect Earth climate.

  16. Design and Implementation of Neuro-Fuzzy Controller Using FPGA for Sun Tracking System

    Directory of Open Access Journals (Sweden)

    Ammar A. Aldair

    2016-12-01

    Full Text Available Nowadays, renewable energy is being used increasingly because of the global warming and destruction of the environment. Therefore, the studies are concentrating on gain of maximum power from this energy such as the solar energy. A sun tracker is device which rotates a photovoltaic (PV panel to the sun to get the maximum power. Disturbances which are originated by passing the clouds are one of great challenges in design of the controller in addition to the losses power due to energy consumption in the motors and lifetime limitation of the sun tracker. In this paper, the neuro-fuzzy controller has been designed and implemented using Field Programmable Gate Array (FPGA board for dual axis sun tracker based on optical sensors to orient the PV panel by two linear actuators. The experimental results reveal that proposed controller is more robust than fuzzy logic controller and proportional-integral (PI controller since it has been trained offline using Matlab tool box to overcome those disturbances. The proposed controller can track the sun trajectory effectively, where the experimental results reveal that dual axis sun tracker power can collect 50.6% more daily power than fixed angle panel. Whilst one axis sun tracker power can collect 39.4 % more daily power than fixed angle panel. Hence, dual axis sun tracker can collect 8 % more daily power than one axis sun tracker.

  17. Development of Fast, Background-Limited Transition-Edge Sensors for the Background-Limited Infrared/Sub-mm Spectrograph (BLISS) for SPICA

    Science.gov (United States)

    Beyer, Andrew D.; Runyan, M. C.; Kenyon, M.; Echternach, P. M .; Chui, T.; Bumble, B.; Bradford, C. M.; Holmes, W. A.; Bock, J. J.

    2012-01-01

    We report experimental progress toward demonstrating background-limited arrays of membrane-isolated transition-edge sensors (TESs) for the Background Limited Infrared/Sub-mm Spectrograph (BLISS). BLISS is a space-borne instrument with grating spectrometers for wavelengths lambda=35-435 micron and with R=lambda/delta lambda approximately equals 500. The goals for BLISS TESs are: noise equivalent power (NEP) = 5x10 (sup -20) W/Hz(exp 1/2) and response time tau = 135mK) and Mo/Cu proximitized bilayers, where T(sub c) is the thermistor transition temperature. We measured the Ir TES arrays in our 50mK adiabatic demagnetization refrigerator test system, which can measure up to eight 1x32 arrays simultaneously using a time-division multiplexer, as well as our single-pixel test system which can measure down to 15mK. In our previous Ir array measurements our best reported performance was NEP=2.5x10(exp -19) W/Hz(sub 1/2) and Tau approximately equals 5ms for straight-beam TESs. In fact, we expected NEP approximately equals 1.5x10(exp -19)?W/Hz(sup 1/2) for meander beam TESs, but did not achieve this previously due to 1/f noise. Here, we detail improvements toward measuring the expected NEP and demonstrate NEP=(1.3+0.2)x10 (sup -19)W/Hz(exp 1/2) in our single-pixel test system and NEP=(1.6+/-0.3)x10(sup -19)W/Hz(sup 1/2) in our array test system.

  18. Development of Fast, Background-Limited Transition-Edge Sensors for the Background-Limited Infrared/Sub-Millimetre Spectrograph (BLISS) for SPICA

    Science.gov (United States)

    Beyer, Andrew D.; Runyan, M. C.; Kenyon, M.; Echternach, P. M.; Chui, T.; Bumble, B.; Bradford, C. M.; Holmes, W. A.; Bock, J. J.

    2012-01-01

    We report experimental progress toward demonstrating background-limited arrays of membrane-isolated transition-edge sensors (TESs) for the Background Limited Infrared/Sub-mm Spectrograph (BLISS). BLISS is a space-borne instrument with grating spectrometers for wavelengths lambda = 35-435 microns and with R = lambda/(delta)lambda approx. 500. The goals for BLISS TESs are: noise equivalent power (NEP) = 5x10(exp -20) W/Hz(1/2) and response time t or = 135mK) and Mo/Cu proximitized bilayers, where T(sub c) is the thermistor transition temperature. We measured the Ir TES arrays in our 50mK adiabatic demagnetization refrigerator test system, which can measure up to eight 1x32 arrays simultaneously using a time-division multiplexer, as well as our single-pixel test system which can measure down to 15mK. In our previous Ir array measurements our best reported performance was NEP=2.5x10(exp -19) W/Hz(1/2) and tapprox.5ms for straight-beam TESs. In fact, we expected NEPapprox.1.5x10(exp -19)W/Hz(1/2) for meander beam TESs, but did not achieve this previously due to 1/f noise. Here, we detail improvements toward measuring the expected NEP and demonstrate NEP=(1.3+0.2)x10(exp -19)W/Hz(1/2) in our single-pixel test system and NEP=(1.6+0.3)x10(exp -19)W/Hz(1/2) in our array test system.

  19. The Sun: Our Nearest Star

    Science.gov (United States)

    Adams, M. L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We have in our celestial backyard, a prime example of a variable star. The Sun, long thought to be "perfect" and unvarying, began to reveal its cycles in the early 1600s as Galileo Galilei and Christoph Scheiner used a telescope to study sunspots. For the past four hundred years, scientists have accumulated data, showing a magnetic cycle that repeats, on average, every eleven (or twenty-two) years. In addition, modern satellites have shown that the energy output at radio and x-ray wavelengths also varies with this cycle. This talk will showcase the Sun as a star and discuss how solar studies may be used to understand other stars.

  20. An Encounter between the Sun and Venus

    CERN Multimedia

    2004-01-01

    The astronomical event of the year will take place on Tuesday, 8 June, when Venus transits across the disk of the sun. In the framework of CERN's 50th anniversary celebrations, the CERN Astronomy Club and the Orion Club invite you to attend their observation of the event on the car park of the Val-Thoiry shopping centre (France) between 7.15 a.m. and 1.30 p.m. Various instruments will be set up in a special tent so that the event can be observed without any risk of damage to the eyes. As the observation of this astronomical event will depend on the weather forecast, confirmation of the above arrangements will be given on the 50th anniversary website the day before.

  1. High-Resolution Gamma-Ray Spectrometers using Bulk Absorbers Coupled to Mo/Cu Multilayer Superconducting Transition-Edge Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Chow, D.T.; Loshak, A.; Van Den Berg, M.L.; Frank, M.; Barbee Jr., T.W.; Labov, S.E.

    2000-07-04

    In x-ray and gamma-ray spectroscopy, it is desirable to have detectors with high energy resolution and high absorption efficiency. At LLNL, we have developed superconducting tunnel junction-based single photon x-ray detectors with thin film absorbers that have achieved these goals for photon energies up to 1 keV. However, for energies above 1 keV, the absorption efficiency of these thin-film detectors decreases drastically. We are developing the use of high-purity superconducting bulk materials as microcalorimeter absorbers for high-energy x-rays and gamma rays. The increase in absorber temperature due to incident photons is sensed by a superconducting transition-edge sensor (TES) composed of a Mo/Cu multilayer thin film. Films of Mo and Cu are mutually insoluble and therefore very stable and can be annealed. The multilayer structure allows scaling in thickness to optimize heat capacity and normal state resistance. We measured an energy resolution of 70 eV for 60 keV incident gamma-rays with a 1 x 1 x 0.25 mm{sup 3} Sn absorber. We present x-ray and gamma-ray results from this detector design with a Sn absorber. We also propose the use of an active negative feedback voltage bias to improve the performance of our detector and show preliminary results.

  2. A dry 3He-4He dilution refrigerator for a transition edge sensor microcalorimeter spectrometer system mounted on a transmission electron microscope

    Science.gov (United States)

    Maehata, K.; Hara, T.; Ito, T.; Yamanaka, Y.; Tanaka, K.; Mitsuda, K.; Yamasaki, N. Y.

    2014-05-01

    A dry 3He-4He dilution refrigerator (DR) was developed for a superconducting transition edge sensor (TES) microcalorimeter installed on a transmission electron microscope. This system could be used for energy dispersive X-ray spectroscopy (EDS) with an excellent energy resolution. A Gifford-McMahon (GM)-type mechanical cryocooler was used as a pre-cooler for the DR to ensure liquid helium was not consumed during operation. To reduce sound and vibrations generated by the GM cryocooler, the DR was separated from the GM cryocooler in a split system. The TES microcalorimeter was glued onto the top of a copper rod referred to as the snout, which was attached to the mixing chamber of the DR. The cooling power in the mixing chamber was 30 μW at 105 mK. The lowest temperature in the mixing chamber was 74 mK, and that at top of the snout was 86 mK. An energy resolution of 7.6 eV full width at half maximum for Si Kα X-rays of 1.74 keV was obtained by TES microcalorimeter EDS performed with the transmission electron microscope.

  3. Day the sun went out

    CERN Multimedia

    2007-01-01

    "A new british sci-fi movie envisages the death of the sun not in billions of years, but in decades. And, amazingly, the film's scientific adviser says this may not be so far from the truth..." (1/2 page)

  4. Effects of Early Sun Exposure

    Science.gov (United States)

    ... can be harmful. It can lead to:Skin changes. Some skin cells with melanin can form a clump. This creates freckles and moles. Over time, these can develop cancer.Early aging. Time spent in the sun makes your skin age faster than normal. Signs of this are wrinkled, tight, or leathery ...

  5. Tracking Planets around the Sun

    Science.gov (United States)

    Riddle, Bob

    2008-01-01

    In earlier columns, the celestial coordinate system of hour circles of right ascension and degrees of declination was introduced along with the use of an equatorial star chart (see SFA Star Charts in Resources). This system shows the planets' motion relative to the ecliptic, the apparent path the Sun follows during the year. An alternate system,…

  6. How Bright Is the Sun?

    Science.gov (United States)

    Berr, Stephen

    1991-01-01

    Presents a sequence of activities designed to allow eighth grade students to deal with one of the fundamental relationships that govern energy distribution. Activities guide students to measure light bulb brightness, discover the inverse square law, compare light bulb light to candle light, and measure sun brightness. (two references) (MCO)

  7. Tracking Planets around the Sun

    Science.gov (United States)

    Riddle, Bob

    2008-01-01

    In earlier columns, the celestial coordinate system of hour circles of right ascension and degrees of declination was introduced along with the use of an equatorial star chart (see SFA Star Charts in Resources). This system shows the planets' motion relative to the ecliptic, the apparent path the Sun follows during the year. An alternate system,…

  8. PLANETARY CONSTRUCTION ZONES IN OCCULTATION: DISCOVERY OF AN EXTRASOLAR RING SYSTEM TRANSITING A YOUNG SUN-LIKE STAR AND FUTURE PROSPECTS FOR DETECTING ECLIPSES BY CIRCUMSECONDARY AND CIRCUMPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Mamajek, Eric E.; Quillen, Alice C.; Pecaut, Mark J.; Moolekamp, Fred; Scott, Erin L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Kenworthy, Matthew A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Cameron, Andrew Collier; Parley, Neil R. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)

    2012-03-15

    The large relative sizes of circumstellar and circumplanetary disks imply that they might be seen in eclipse in stellar light curves. We estimate that a survey of {approx}10{sup 4} young ({approx}10 million year old) post-accretion pre-main-sequence stars monitored for {approx}10 years should yield at least a few deep eclipses from circumplanetary disks and disks surrounding low-mass companion stars. We present photometric and spectroscopic data for a pre-main-sequence K5 star (1SWASP J140747.93-394542.6 = ASAS J140748-3945.7), a newly discovered {approx}0.9 M{sub Sun} member of the {approx}16 Myr old Upper Centaurus-Lupus subgroup of Sco-Cen at a kinematic distance of 128 {+-} 13 pc. This star exhibited a remarkably long, deep, and complex eclipse event centered on 2007 April 29 (as discovered in Super Wide Angle Search for Planets (SuperWASP) photometry, and with portions of the dimming confirmed by All Sky Automated Survey (ASAS) data). At least five multi-day dimming events of >0.5 mag are identified, with a >3.3 mag deep eclipse bracketed by two pairs of {approx}1 mag eclipses symmetrically occurring {+-}12 days and {+-}26 days before and after. Hence, significant dimming of the star was taking place on and off over at least a {approx}54 day period in 2007, and a strong >1 mag dimming event occurring over a {approx}12 day span. We place a firm lower limit on the period of 850 days (i.e., the orbital radius of the eclipser must be >1.7 AU and orbital velocity must be <22 km s{sup -1}). The shape of the light curve is similar to the lopsided eclipses of the Be star EE Cep. We suspect that this new star is being eclipsed by a low-mass object orbited by a dense inner disk, further girded by at least three dusty rings of optical depths near unity. Between these rings are at least two annuli of near-zero optical depth (i.e., gaps), possibly cleared out by planets or moons, depending on the nature of the secondary. For possible periods in the range 2.33-200 yr, the

  9. Capturing small asteroids into a Sun-Earth Lagrangian point

    Science.gov (United States)

    Lladó, Neus; Ren, Yuan; Masdemont, Josep J.; Gómez, Gerard

    2014-02-01

    In this paper we address the feasibility of capturing small Near-Earth Asteroids (NEAs) into the vicinity of the Sun-Earth L2 libration point using a continuous-thrust propulsion system assumed to be attached to the asteroid. The vicinity of this libration point is a gateway to the Earth-Moon neighborhood and using it for capture, or for transit, small NEAs could be interesting for mining or science purposes.

  10. The Sun Radio Imaging Space Experiment (SunRISE) Mission

    Science.gov (United States)

    Lazio, Joseph; Kasper, Justin; Maksimovic, Milan; Alibay, Farah; Amiri, Nikta; Bastian, Tim; Cohen, Christina; Landi, Enrico; Manchester, Ward; Reinard, Alysha; Schwadron, Nathan; Cecconi, Baptiste; Hallinan, Gregg; Hegedus, Alex; Krupar, Vratislav; Zaslavsky, Arnaud

    2017-04-01

    Radio emission from coronal mass ejections (CMEs) is a direct tracer of particle acceleration in the inner heliosphere and potential magnetic connections from the lower solar corona to the larger heliosphere. Energized electrons excite Langmuir waves, which then convert into intense radio emission at the local plasma frequency, with the most intense acceleration thought to occur within 20 RS. The radio emission from CMEs is quite strong such that only a relatively small number of antennas is required to detect and map it, but many aspects of this particle acceleration and transport remain poorly constrained. Ground-based arrays would be quite capable of tracking the radio emission associated with CMEs, but absorption by the Earth's ionosphere limits the frequency coverage of ground-based arrays (ν ≳ 15 MHz), which in turn limits the range of solar distances over which they can track the radio emission (≲ 3RS). The state-of-the-art for tracking such emission from space is defined by single antennas (Wind/WAVES, Stereo/SWAVES), in which the tracking is accomplished by assuming a frequency-to-density mapping; there has been some success in triangulating the emission between the spacecraft, but considerable uncertainties remain. We describe the Sun Radio Imaging Space Experiment (SunRISE) mission concept: A constellation of small spacecraft in a geostationary graveyard orbit designed to localize and track radio emissions in the inner heliosphere. Each spacecraft would carry a receiving system for observations below 25 MHz, and SunRISE would produce the first images of CMEs more than a few solar radii from the Sun. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  11. Removing sun glint from optical remote sensing images of shallow rivers

    Science.gov (United States)

    Overstreet, Brandon T.; Legleiter, Carl

    2017-01-01

    Sun glint is the specular reflection of light from the water surface, which often causes unusually bright pixel values that can dominate fluvial remote sensing imagery and obscure the water-leaving radiance signal of interest for mapping bathymetry, bottom type, or water column optical characteristics. Although sun glint is ubiquitous in fluvial remote sensing imagery, river-specific methods for removing sun glint are not yet available. We show that existing sun glint-removal methods developed for multispectral images of marine shallow water environments over-correct shallow portions of fluvial remote sensing imagery resulting in regions of unreliable data along channel margins. We build on existing marine glint-removal methods to develop a river-specific technique that removes sun glint from shallow areas of the channel without overcorrection by accounting for non-negligible water-leaving near-infrared radiance. This new sun glint-removal method can improve the accuracy of spectrally-based depth retrieval in cases where sun glint dominates the at-sensor radiance. For an example image of the gravel-bed Snake River, Wyoming, USA, observed-vs.-predicted R2 values for depth retrieval improved from 0.66 to 0.76 following sun glint removal. The methodology presented here is straightforward to implement and could be incorporated into image processing workflows for multispectral images that include a near-infrared band.

  12. Tanel Padar & The Sun veab õhukitarri

    Index Scriptorium Estoniae

    2008-01-01

    Õhukitarri Eesti meistrivõistlustest 19. apr. Tallinnas Rock Cafés (võistluste eestvedajaks on ansambel Tanel Padar & The Sun, kes samas esitleb oma esimest ingliskeelset albumit "Here Comes The Sun")

  13. Tanel Padar & The Sun veab õhukitarri

    Index Scriptorium Estoniae

    2008-01-01

    Õhukitarri Eesti meistrivõistlustest 19. apr. Tallinnas Rock Cafés (võistluste eestvedajaks on ansambel Tanel Padar & The Sun, kes samas esitleb oma esimest ingliskeelset albumit "Here Comes The Sun")

  14. Transition Operators

    CERN Document Server

    Alcock-Zeilinger, Judith

    2016-01-01

    In this paper, we give a generic algorithm of the transition operators between Hermitian Young projection operators corresponding to equivalent irreducible representations of SU(N), using the compact expressions of Hermitian Young projection operators derived in a companion paper. We show that the Hermitian Young projection operators together with their transition operators constitute a fully orthogonal basis for the algebra of invariants of $V^{\\otimes m}$ that exhibits a systematically simplified multiplication table. We discuss the full algebra of invariants over $V^{\\otimes 3}$ and $V^{\\otimes 4}$ as explicit examples. In our presentation we make use of various standard concepts such as Young projection operators, Clebsch-Gordan operators, and invariants (in birdtrack notation). We tie these perspectives together and use them to shed light on each other.

  15. Caddo Sun Accounts across Time and Place

    Science.gov (United States)

    Gerona, Carla

    2012-01-01

    Billy Day, a Tunica/Biloxi, recently described the significance of the sun for Caddoan people. Day quoted an "old Caddo relative" of his who said: "I used to go outside and hold my hands up and bless myself with the sun--'a'hat.' Well, I can't do that anymore because they say we are sun worshipers. We didn't worship the sun. We worshiped what was…

  16. Global Warming Blame the Sun

    CERN Document Server

    Calder, N

    1997-01-01

    Concern about climate change reaches a political peak at a UN conference in Kyoto, 1-10 December, but behind the scenes the science is in turmoil. A challenge to the hypothesis that greenhouse gases are responsible for global warming comes from the discovery that cosmic rays from the Galaxy are involved in making clouds (Svensmark and Friis-Christensen, 1997). During the 20th Century the wind from the Sun has grown stronger and the count of cosmic rays has diminished. With fewer clouds, the EarthÕs surface has warmed up. This surprising mechanism explains the link between the Sun and climate change that astronomers and geophysicists have suspected for 200 years.

  17. Transition-edge sensor pixel parameter design of the microcalorimeter array for the x-ray integral field unit on Athena

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Bandler, S. R.; Betancourt-Martinez, G. L.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Miniussi, A. R.; Porter, F. S.; Sadleir, J. E.; Sakai, K.; Wakeham, N. A.; Wassell, E. J.; Yoon, W.; Bennett, D. A.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Morgan, K. M.; Pappas, C. G.; Reintsema, C. N.; Swetz, D. S.; Ullom, J. N.; Irwin, K. D.; Akamatsu, H.; Gottardi, L.; den Hartog, R.; Jackson, B. D.; van der Kuur, J.; Barret, D.; Peille, P.

    2016-07-01

    The focal plane of the X-ray integral field unit (X-IFU) for ESA's Athena X-ray observatory will consist of 4000 transition edge sensor (TES) x-ray microcalorimeters optimized for the energy range of 0.2 to 12 keV. The instrument will provide unprecedented spectral resolution of 2.5 eV at energies of up to 7 keV and will accommodate photon fluxes of 1 mCrab (90 cps) for point source observations. The baseline configuration is a uniform large pixel array (LPA) of 4.28" pixels that is read out using frequency domain multiplexing (FDM). However, an alternative configuration under study incorporates an 18 × 18 small pixel array (SPA) of 2" pixels in the central 36" region. This hybrid array configuration could be designed to accommodate higher fluxes of up to 10 mCrab (900 cps) or alternately for improved spectral performance (report on the TES pixel designs that are being optimized to meet these proposed LPA and SPA configurations. In particular we describe details of how important TES parameters are chosen to meet the specific mission criteria such as energy resolution, count-rate and quantum efficiency, and highlight performance trade-offs between designs. The basis of the pixel parameter selection is discussed in the context of existing TES arrays that are being developed for solar and x-ray astronomy applications. We describe the latest results on DC biased diagnostic arrays as well as large format kilo-pixel arrays and discuss the technical challenges associated with integrating different array types on to a single detector die.

  18. A transition-edge-sensor-based instrument for the measurement of individual He2* excimers in a superfluid 4He bath at 100 mK

    Science.gov (United States)

    Carter, Faustin Wirkus

    This dissertation is an account of the first calorimetric detection of individual He*2 excimers within a bath of superfluid 4He. When superfluid helium is subject to ionizing radiation, diatomic He molecules are created in both the singlet and triplet states. The singlet He molecules decay within nanoseconds, but due to a forbidden spin-flip the triplet molecules have a relatively long lifetime of 13 seconds in superfluid He. When He* 2 molecules decay, they emit a ~15 eV photon. Nearly all matter is opaque to these vacuum-UV photons, although they do propagate through liquid helium. The triplet state excimers propagate ballistically through the superfluid until they quench upon a surface; this process deposits a large amount of energy into the surface. The prospect of detecting both excimer states is the motivation for building a detector immersed directly in the superfluid bath. The detector used in this work is a single superconducting titanium transition edge sensor (TES). The TES is mounted inside a hermetically sealed chamber at the baseplate of a dilution refrigerator. The chamber contains superfluid helium at 100 mK. Excimers are created during the relaxation of high-energy electrons, which are introduced into the superfluid bath either in situ via a sharp tungsten tip held above the field-emission voltage, or by using an external gamma-ray source to ionize He atoms. These excimers either propagate through the LHe bath and quench on a surface, or decay and emit vacuum-ultraviolet photons that can be collected by the detector. This dissertation discusses the design, construction, and calibration of the TES-based excimer detecting instrument. It also presents the first spectra resulting from the direct detection of individual singlet and triplet helium excimers.

  19. Role of cyclic AMP sensor Epac1 in masseter muscle hypertrophy and myosin heavy chain transition induced by β2-adrenoceptor stimulation.

    Science.gov (United States)

    Ohnuki, Yoshiki; Umeki, Daisuke; Mototani, Yasumasa; Jin, Huiling; Cai, Wenqian; Shiozawa, Kouichi; Suita, Kenji; Saeki, Yasutake; Fujita, Takayuki; Ishikawa, Yoshihiro; Okumura, Satoshi

    2014-12-15

    The predominant isoform of β-adrenoceptor (β-AR) in skeletal muscle is β2-AR and that in the cardiac muscle is β1-AR. We have reported that Epac1 (exchange protein directly activated by cAMP 1), a new protein kinase A-independent cAMP sensor, does not affect cardiac hypertrophy in response to pressure overload or chronic isoproterenol (isoprenaline) infusion. However, the role of Epac1 in skeletal muscle hypertrophy remains poorly understood. We thus examined the effect of disruption of Epac1, the major Epac isoform in skeletal muscle, on masseter muscle hypertrophy induced by chronic β2-AR stimulation with clenbuterol (CB) in Epac1-null mice (Epac1KO). The masseter muscle weight/tibial length ratio was similar in wild-type (WT) and Epac1KO at baseline and was significantly increased in WT after CB infusion, but this increase was suppressed in Epac1KO. CB treatment significantly increased the proportion of myosin heavy chain (MHC) IIb at the expense of that of MHC IId/x in both WT and Epac1KO, indicating that Epac1 did not mediate the CB-induced MHC isoform transition towards the faster isoform. The mechanism of suppression of CB-mediated hypertrophy in Epac1KO is considered to involve decreased activation of Akt signalling. In addition, CB-induced histone deacetylase 4 (HDAC4) phosphorylation on serine 246 mediated by calmodulin kinase II (CaMKII), which plays a role in skeletal muscle hypertrophy, was suppressed in Epac1KO. Our findings suggest that Epac1 plays a role in β2-AR-mediated masseter muscle hypertrophy, probably through activation of both Akt signalling and CaMKII/HDAC4 signalling. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

  20. Total eclipses of the sun.

    Science.gov (United States)

    Zirker, J B

    1980-12-19

    Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans.

  1. Revisiting SU(N) integrals

    CERN Document Server

    Zuber, Jean-Bernard

    2016-01-01

    In this note, I revisit integrals over $\\SU(N)$ of the form $ \\int DU\\, U_{i_1j_1}\\cdots U_{i_pj_p}\\Ud_{k_1l_1}\\cdots \\Ud_{k_nl_n}$. While the case $p=n$ is well known, it seems that explicit expressions for $p=n+N$ had not appeared in the literature. Similarities and differences, in particular in the large $N$ limit, between the two cases are discussed

  2. Coherent States with SU(N) Charges

    CERN Document Server

    Mathur, M; Mathur, Manu; Paul, Samir K.

    2003-01-01

    We define coherent states carrying SU(N) charges by exploiting generalized Schwinger boson representation of SU(N) Lie algebra. These coherent states are defined on $2 (2^{N - 1} - 1)$ complex planes. They satisfy continuity property and provide resolution of identity. We also exploit this technique to construct the corresponding non-linear SU(N) coherent states.

  3. The Sun Rises on the Solar Sector

    OpenAIRE

    Ahmad, Reyaz A.

    2009-01-01

    Energy from the sun is abundant and free. Solar energy is in essence electromagnetic radiation emitted from the sun. Earth's climate, hydrologic systems, and ecosystems all derive from the sun. Other forms of renewable power such as wind, wave, biomass, and hydro are an indirect function of solar radiation.

  4. The Sun A User's Manual

    CERN Document Server

    Vita-Finzi, Claudio

    2008-01-01

    The Sun is an account of the many ways in which our nearest star affects our planet, how its influence has changed over the last few centuries and millennia, and the extent to which we can predict its future impact. The Sun's rays foster the formation of Vitamin D by our bodies, but it can also promote skin cancer, cataracts, and mutations in our DNA. Besides providing the warmth and light essential to most animal and plant life, solar energy contributes substantially to global warming. Although the charged particles of the solar wind shield us from harmful cosmic rays, solar storms may damage artificial satellites and cripple communication systems and computer networks. The Sun is the ideal renewable energy source, but its exploitation is still bedevilled by the problems of storage and distribution. Our nearest star, in short, is a complex machine which needs to be treated with caution, and this book will equip every reader with the knowledge that is required to understand the benefits and dangers it can bri...

  5. The faint young Sun problem

    CERN Document Server

    Feulner, Georg

    2012-01-01

    For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the `faint young Sun problem'. For the early Earth, models of stellar evolution predict a solar energy input to the climate system which is about 25% lower than today. This would result in a completely frozen world over the first two billion years in the history of our planet, if all other parameters controlling Earth's climate had been the same. Yet there is ample evidence for the presence of liquid surface water and even life in the Archean (3.8 to 2.5 billion years before present), so some effect (or effects) must have been compensating for the faint young Sun. A wide range of possible solutions have been suggested and explored during the last four decades, with most studies focusing on higher concentrations of atmospheric greenhouse gases like carbon dioxide, methane or ammonia. All of these solutions present considerable difficulties, however, so the faint young Sun prob...

  6. Sun Savvy Students: Free Teaching Resources from EPA's SunWise Program

    Science.gov (United States)

    Hall-Jordan, Luke

    2008-01-01

    With summer in full swing and the sun is naturally on our minds, what better time to take advantage of a host of free materials provided by the U.S. Environmental Protection Agency's Sun Wise program. Sun Wise aims to teach students and teachers about the stratospheric ozone layer, ultraviolet (UV) radiation, and how to be safe while in the Sun.…

  7. Development of a microprocessor-based Sun-tracking system for solar collectors

    Science.gov (United States)

    Kohler, S. M.; Wilcoxen, J. L.

    1980-04-01

    The development of a prototype Sun-tracking system and the tests performed on it on an east-west trough solar collector array are described. The system includes a controller built around an RCA1802 microprocessor, a digital shaft encoder, and a heat flux sensor. The heat flux sensor consists of a fine resistance wire wrapped around the receiver tube. The wire is used to correct errors in calculated tracking angles arising from reflector imperfections and misalignments.

  8. Development of a microprocessor-based sun-tracking system for solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, S.M.; Wilcoxen, J.L.

    1980-04-01

    The development of a prototype sun-tracking system and the tests performed on it on an east-west trough solar collector array are described. The system includes a controller built around an RCA1802 microprocessor (..mu..P), a digital shaft encoder, and a heat flux sensor. The heat flux sensor consists of a fine resistance wire wrapped around the receiver tube. The wire is used to correct errors in calculated tracking angles arising from reflector imperfections and misalignments.

  9. Catastrophic rotational braking among Sun-like stars. A model of the Sun's rotation evolution

    Science.gov (United States)

    Gondoin, P.

    2017-03-01

    Context. Observations of young open clusters show a bimodal distribution of stellar rotation. In those clusters, Sun-like stars group into two main populations of fast and slow rotators. Beyond an age of approximately 600 Myr, the two populations converge towards a single sequence of slow rotators. Aims: The present study addresses the origin of this bimodal distribution and the cause of its observed evolution. Methods: New prescriptions of mass-loss rate and Alfven radius dependences on Rossby number suggested by observations are implemented in a phenomenological model of angular-momentum loss and redistribution. The obtained model is used to calculate the time evolution of a rotation-period distribution of solar-mass stars similar to that observed in the 5 Myr-old NGC 2362 open cluster. The simulated distributions at subsequent ages are compared with those of h Per, the Pleiades, M 50, M 35, and M 37. Results: The model is able to reproduce the appearance and disappearance of a bimodal rotation-period distribution in open clusters providing that a brief episode of large-angular-momentum loss is included in the early evolution of Sun-like stars. Conclusions: I argue that a transitory episode of large-angular-momentum loss occurs on Sun-like stars with Rossby numbers between 0.13 and 0.3. This phenomenon of enhanced magnetic braking by stellar wind would be mainly driven by a rapid increase of mass loss at a critical rotation rate. This scenario accounts for the bimodal distribution of stellar rotation in open clusters with ages between 20-30 Myr and approximately 600 Myr. The mass-loss rate increase could account for a significant fraction of the X-ray luminosity decay of Sun-like stars in the 0.13-0.3 Rossby number range where a transition from the saturated to the non-saturated regime of X-ray emission is observed. Observed correlations between Li abundance and rotation sequences in the Pleiades and M 34 clusters support this scenario.

  10. Solar flare leaves sun quaking

    Science.gov (United States)

    1998-05-01

    Dr. Alexander G. Kosovichev, a senior research scientist from Stanford University, and Dr. Valentina V. Zharkova from Glasgow (United Kingdom) University found the tell-tale seismic signature in data on the Sun's surface collected by the Michelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO) spacecraft immediately following a moderate-sized flare on July 9, 1996. "Although the flare was a moderate one, it still released an immense amount of energy," said Dr. Craig Deforest, a researcher with the SOHO project. "The energy released is equal to completely covering the Earth's continents with a yard of dynamite and detonating it all at once." SOHO is a joint project of the European Space Agency and NASA. The finding is reported in the May 28 issue of the journal Nature, and is the subject of a press conference at the spring meeting of the American Geophysical Union in Boston, Mass., May 27. The solar quake that the science team recorded looks much like ripples spreading from a rock dropped into a pool of water. But over the course of an hour, the solar waves traveled for a distance equal to 10 Earth diameters before fading into the fiery background of the Sun's photosphere. Unlike water ripples that travel outward at a constant velocity, the solar waves accelerated from an initial speed of 22,000 miles per hour to a maximum of 250,000 miles per hour before disappearing. "People have looked for evidence of seismic waves from flares before, but they didn't have a theory so they didn't know where to look," says Kosovichev. Several years ago Kosovichev and Zharkova developed a theory that can explain how a flare, which explodes in space above the Sun's surface, can generate a major seismic wave in the Sun's interior. According to the currently accepted model of solar flares, the primary explosion creates high-energy electrons (electrically charged subatomic particles). These are funneled down into a magnetic flux tube, an invisible tube of magnetic

  11. Seismology of the Wounded Sun

    CERN Document Server

    Cally, Paul S

    2013-01-01

    Active regions are open wounds in the Sun's surface. Seismic oscillations from the interior pass through them into the atmosphere, changing their nature in the process to fast and slow magneto-acoustic waves. The fast waves then partially reflect and partially mode convert to upgoing and downgoing Alfv\\'en waves. The reflected fast and downgoing Alfv\\'en waves then re-enter the interior through the active regions that spawned them, infecting the surface seismology with signatures of the atmosphere. Using numerical simulations of waves in uniform magnetic fields, we calculate the upward acoustic and Alfv\\'enic losses in the atmosphere as functions of field inclination and wave orientation as well as the Time-Distance `travel time' perturbations, and show that they are related. Travel time perturbations relative to quiet Sun can exceed 40 seconds in 1 kG magnetic field. It is concluded that active region seismology is indeed significantly infected by waves leaving and re-entering the interior through magnetic w...

  12. The Sun's New Exotic Neighbour

    Science.gov (United States)

    2006-03-01

    Using ESO's Very Large Telescope in Chile, an international team of researchers [1] discovered a brown dwarf belonging to the 24th closest stellar system to the Sun. Brown dwarfs are intermediate objects that are neither stars nor planets. This object is the third closest brown dwarf to the Earth yet discovered, and one of the coolest, having a temperature of about 750 degrees Celsius. It orbits a very small star at about 4.5 times the mean distance between the Earth and the Sun. Its mass is estimated to be somewhere between 9 and 65 times the mass of Jupiter. At a time when astronomers are peering into the most distant Universe, looking at objects as far as 13 billion light-years away, one may think that our close neighbourhood would be very well known. Not so. Astronomers still find new star-like objects in our immediate vicinity. Using ESO's VLT, they just discovered a brown dwarf companion to the red star SCR 1845-6357, the 36th closest star to the Sun. ESO PR Photo 11/06 ESO PR Photo 11a/06 New Brown Dwarf in the Solar Neighbourhood (Artist's Impression) "This newly found brown dwarf is a valuable object because its distance is well known, allowing us to determine with precision its intrinsic brightness", said team member Markus Kasper (ESO). "Moreover, from its orbital motion, we should be able in a few years to estimate its mass. These properties are vital for understanding the nature of brown dwarfs." To discover this brown dwarf, the team used the high-contrast adaptive optics NACO Simultaneous Differential Imager (SDI [2]) on ESO's Very Large Telescope, an instrument specifically developed to search for extrasolar planets. The SDI camera enhances the ability of the VLT and its adaptive optics system to detect faint companions that would normally be lost in the glare of the primary star. In particular, the SDI camera provides additional, often very useful spectral information which can be used to determine a rough temperature for the object without follow

  13. Here comes the sun...; Here comes the sun...

    Energy Technology Data Exchange (ETDEWEB)

    Best, Robert [Centro de Investigacion en Energia (CIE) de la UNAM, Temixco, Morelos (Mexico)

    2010-07-01

    It sounds a bit strange that you can use solar energy to maintain or refrigerate products or spaces below the ambient temperature, because we know that something that makes the sun is heating; but yes indeed, the sun can produce cold, and in addition without polluting, and without consuming conventional energy. In this document are mentioned the various research projects on solar cooling that have been made in the Energy Research Center at the Universidad Nacional Autonoma de Mexico such as the thermo-chemical intermittent refrigerator, the geothermal cooling demonstration system in Mexicali, B.C., the GAX system for air conditioning, the ice producer intermittent solar refrigerator, the continuous solar refrigerator, the refrigeration by ejection-compression. It also mentions the functioning of heat pumps and the process of solar drying applications in agricultural products. [Spanish] Suena un poco extrano que se pueda utilizar la energia solar para mantener o refrigerar productos o espacios por debajo de la temperatura ambiente, ya que sabemos que algo que hace el sol es calentar; pero si, el sol puede producir frio, y ademas sin contaminar y sin consumir energia convencional. En este documento se mencionan las diferentes investigaciones sobre refrigeracion solar que se han realizado en el Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico como el refrigerador termoquimico intermitente, el sistema demostrativo de refrigeracion geotermico en Mexicali, B.C., el sistema GAX para aire acondicionado, el refrigerador solar intermitente productor de hielo, el refrigerador continuo solar, la refrigeracion por eyecto-compresion. Tambien se menciona el funcionamiento de las bombas de calor y el proceso de secado solar de aplicacion en productos agropecuarios.

  14. Saturation of Stellar Winds from Young Suns

    CERN Document Server

    Suzuki, Takeru K; Kataoka, Ryuho; Kato, Yoshiaki; Matsumoto, Takuma; Miyahara, Hiroko; Tsuneta, Saku

    2013-01-01

    (Abridged)We investigate mass losses via stellar winds from sun-like main sequence stars with a wide range of activity levels. We perform forward-type magnetohydrodynamical numerical experiments for Alfven wave-driven stellar winds with a wide range of the input Poynting flux from the photosphere. Increasing the magnetic field strength and the turbulent velocity at the stellar photosphere from the current solar level, the mass loss rate rapidly increases at first owing to the suppression of the reflection of the Alfven waves. The surface materials are lifted up by the magnetic pressure associated with the Alfven waves, and the cool dense chromosphere is intermittently extended to 10-20% of the stellar radius. The densities of the corona and transition region above the chromosphere is also high, which leads to efficient radiative losses. Eventually most of the input Poynting energy from the stellar surface escapes by the radiation. As a result, there is no more sufficient energy remained for the kinetic energy...

  15. TRIGONOMETRIC SU(N) GAUDIN MODEL

    Institute of Scientific and Technical Information of China (English)

    曹俊鹏; 侯伯宇; 岳瑞宏

    2001-01-01

    In this paper, we obtain the eigenstates and the eigenvalues of the Hamiltonians of the trigonometric SU(N) Gaudin model based on the quasi-classical limit of the trigonometric SU(N) chain with the periodic boundary condition.By using the quantum inverse scattering method, we also obtain the eigenvalues of the generating function of the trigonometric SU(N) Gaudin model.

  16. The summer sun shone round me

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The summer sun shone round me, The folded valley lay In a stream of sun and odour, That sultry summer day. The tall trees stood in the sunlight As still as still could be, But the deep grass sighed and rustled And bowed and beckoned me. The deep grass moved and whispered And bowed and brushed my face. It whis pered in the sunshine: The winter comes apdce.”The summer sun shone round me

  17. Sun awareness in Maltese secondary school students.

    Science.gov (United States)

    Aquilina, S; Gauci, A Amato; Ellul, M; Scerri, L

    2004-11-01

    Studies indicate that reducing exposure to ultraviolet light during childhood and adolescence decreases the risk of skin cancer. From a young age, children need to be educated about the sun's harmful effects on the skin and how best to protect themselves. To help in the design of school-based interventions to raise sun awareness, a school survey was carried out to identify students' stereotypes and misconceptions. A total of 965 students attending Maltese secondary schools in forms 1, 2 and 3 were surveyed in May 2002, using a structured questionnaire designed to examine students' sun-related attitudes and knowledge. A high level of sun awareness among students was demonstrated, with high scores on knowledge of the effects of the sun on the skin, knowledge of skin cancer and knowledge of sun protection. Girls were clearly more knowledgeable than boys. However, of all the students surveyed, 55% thought that a suntan made them look better and 70% thought that their friends would desire a tan. These views were commoner among the older students. Skin type and hair or eye colour had no bearing on attitudes towards tanning or sun-related knowledge. The commonest misconceptions were that 'the sun is bad for your skin only when you get sunburnt' and that 'you cannot get too much sun on a cloudy day'. Deliberate suntanning was more frequently reported by girls than by boys and by students in the higher forms. Attitude change lags behind knowledge. Future school sun awareness interventions need to take into account gender and age differences in students' attitudes and perspectives. They should aim at motivating attitude change and preventive behaviour through consistent and repeated sun-education messages that are supported by a sun-conscious school environment.

  18. Sun Jingxia Devotes Herself to Nursing Work

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    "I really didn’t expect that at my advanced age, I would be awarded the highest honor in international nursing circles," said Mme. Sun Jingxia, 81, who had just returned from Beijing where she received the Nightingale Medal. Wearing a light yellow suit, with a collar bordered in red, Sun is inhigh spirits, reminding people of the beauty of the setting sun. It is clear that Sun Jingxia has deep feelings as she looks at the medal which shows a relief of Florence Nightingale’s head. She spoke in her usual soft voice but with some excitement, "President Jiang

  19. HALLIBURTON SPERRY-SUN DOE HIGH TEMPERATURE LWD PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Spross

    2005-03-15

    The objective of this project was to build a high temperature, cost-effective, logging while drilling (HT-LWD) system with the ability to operate at 175 C with more than 100 hours mean time between failures (MTBF). Such a commercial real-time formation evaluation (FE) system would help operators to drill and produce hydrocarbon resources from moderately deep, hot reservoirs which otherwise might be uneconomic to drill. The project plan was to combine the existing Sperry-Sun high temperature directional and gamma logging system with lower temperature FE sensors which were upgraded to higher temperature operation as part of the project. The project was to be completed in two phases. Phase I included the development of the HT system, building two complete systems, demonstrating operational capability at 175 C and survivability at 200 C in the laboratory, and successfully testing the system in two low temperature field tests. Phase II was to test the system in a well with a bottom hole temperature of 175 C. The high temperature FE sensors developed as part of this project include gamma ray (DGR), resistivity (EWR-Phase 4), neutron (CTN), and density (SLD). The existing high temperature pulser and telemetry system was upgraded to accommodate the data and bandwidth requirements of the additional sensors. Environmental and lifetime testing of system components and modules indicates that system life and reliability goals will be substantially exceeded. The system has performed well in domestic and international high temperature wells (to 175 C). In addition to the sensor modules specified in the project contract, Sperry has now upgraded other system components to higher temperature as well. These include a LWD sonic sensor (BAT), pressure while drilling sensor (PWD), and a more powerful central system controller (CIM).

  20. Regina vs Hubbs: Determining the Sun's Position

    CERN Document Server

    Samra, Raminder Singh

    2012-01-01

    Here I determined the Sun's position as an expert witness for crown counsel. From my calculations I found the Sun's location in the sky was such that it could not impede the driver's vision, as a result it could not have been the reason for the accused to be involved in a motor vehicle accident.

  1. Mitochondrial DNA deletion percentage in sun exposed and non sun exposed skin.

    Science.gov (United States)

    Powers, Julia M; Murphy, Gillian; Ralph, Nikki; O'Gorman, Susan M; Murphy, James E J

    2016-12-01

    The percentages of mitochondrial genomes carrying the mtDNA(3895) and the mtDNA(4977) (common) deletion were quantified in sun exposed and non sun exposed skin biopsies, for five cohorts of patients varying either in sun exposure profile, age or skin cancer status. Non-melanoma skin cancer diagnoses are rising in Ireland and worldwide [12] but most risk prediction is based on subjective visual estimations of sun exposure history. A quantitative objective test for pre-neoplastic markers may result in better adherence to sun protective behaviours. Mitochondrial DNA (mtDNA) is known to be subject to the loss of a significant proportion of specific sections of genetic code due to exposure to ultraviolet light in sunlight. Although one such deletion has been deemed more sensitive, another, called the mtDNA(4977) or common deletion, has proved to be a more useful indicator of possible risk in this study. Quantitative molecular analysis was carried out to determine the percentage of genomes carrying the deletion using non sun exposed and sun exposed skin biopsies in cohorts of patients with high or low sun exposure profiles and two high exposure groups undergoing treatment for NMSC. Results indicate that mtDNA deletions correlate to sun exposure; in groups with high sun exposure habits a significant increase in deletion number in exposed over non sun exposed skin occurred. An increase in deletion percentage was also seen in older cohorts compared to the younger group. The mtDNA(3895) deletion was detected in small amounts in exposed skin of many patients, the mtDNA(4977) common deletion, although present to some extent in non sun exposed skin, is suggested to be the more reliable and easily detected marker. In all cohorts except the younger group with relatively lower sun exposure, the mtDNA(4977) deletion was more frequent in sun exposed skin samples compared to non-sun exposed skin.

  2. Gravitational Lensing Characteristics of the Transparent Sun

    CERN Document Server

    Patla, Bijunath

    2007-01-01

    The transparent Sun is modeled as a spherically symmetric and centrally condensed gravitational lens using recent Standard Solar Model (SSM) data. The Sun's minimum focal length is computed to a refined accuracy of 23.5 +/- 0.1 AU, just beyond the orbit of Uranus. The Sun creates a single image of a distant point source visible to observers inside this minimum focal length and to observers sufficiently removed from the line connecting the source through the Sun's center. Regions of space are mapped where three images of a distant point source are created, along with their associated magnifications. Solar caustics, critical curves, and Einstein rings are computed and discussed. Extremely high gravitational lens magnifications exist for observers situated so that an angularly small, unlensed source appears near a three-image caustic. Types of radiations that might undergo significant solar lens magnifications as they can traverse the core of the Sun, including neutrinos and gravitational radiation, are discusse...

  3. Vibration Based Sun Gear Damage Detection

    Science.gov (United States)

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  4. Optical technologies for space sensor

    Science.gov (United States)

    Wang, Hu; Liu, Jie; Xue, Yaoke; Liu, Yang; Liu, Meiying; Wang, Lingguang; Yang, Shaodong; Lin, Shangmin; Chen, Su; Luo, Jianjun

    2015-10-01

    Space sensors are used in navigation sensor fields. The sun, the earth, the moon and other planets are used as frame of reference to obtain stellar position coordinates, and then to control the attitude of an aircraft. Being the "eyes" of the space sensors, Optical sensor system makes images of the infinite far stars and other celestial bodies. It directly affects measurement accuracy of the space sensor, indirectly affecting the data updating rate. Star sensor technology is the pilot for Space sensors. At present more and more attention is paid on all-day star sensor technology. By day and night measurements of the stars, the aircraft's attitude in the inertial coordinate system can be provided. Facing the requirements of ultra-high-precision, large field of view, wide spectral range, long life and high reliability, multi-functional optical system, we integration, integration optical sensors will be future space technology trends. In the meantime, optical technologies for space-sensitive research leads to the development of ultra-precision optical processing, optical and precision test machine alignment technology. It also promotes the development of long-life optical materials and applications. We have achieved such absolute distortion better than ±1um, Space life of at least 15years of space-sensitive optical system.

  5. JPSS-1 VIIRS solar diffuser stability monitor response versus sun angle of incidence

    Science.gov (United States)

    Murgai, Vijay; Yu, Kristie; Nelson, Neil; McCarthy, James

    2015-09-01

    The Visible/Infrared Imaging Radiometer Suite (VIIRS) is a key sensor on the Suomi National Polar-orbiting Partnership (NPP) satellite in orbit as well as for the upcoming Joint Polar Satellite System (JPSS). VIIRS collects Earth radiometry and imagery in 22 spectral from 0.4 to 12.5 μm. Radiometric calibration of the reflective bands in the 0.4 to 2.5 μm wavelength range is performed by measuring the sunlight reflectance from Solar Diffuser Assembly (diffuser is Spectralon®). Spectralon® is known to solarize due to sun UV exposure at the blue end of the spectrum (~0.4 - 0.6+ μm) as seen by laboratory tests as well as on orbit data from MODIS and NPP. VIIRS uses a Solar Diffuser Stability Monitor (SDSM) to monitor the change in the Solar Diffuser reflectance in the 0.4 - 0.94 μm wavelength range to correct the calibration constants. The SDSM measures the ratio of sun light reflecting from the Solar Diffuser to a direct view of the sun. As the intensity of the light reaching the SDSM in both Solar Diffuser view and sun view is a function of the sun's angle of incidence (AOI), the SDSM response to sun AOI has to be characterized. This paper presents details of the test setup including an extended collimated source simulating the sun across all SDSM bands. The prelaunch characterization results for the JPSS-1 (J1) VIIRS SDSM are presented. Comparison with NPP on orbit yaw maneuver SDSM results shows similar behavior demonstrating that the J1 test successfully characterized the SDSM response to sun AOI.

  6. The Sun and How to Observe It

    CERN Document Server

    Jenkins, Jamey L

    2009-01-01

    Without the Sun, all life on Earth would perish. But what exactly do we know about this star that lights, heats, and powers Earth? Actually, we know quite a lot, thanks mainly to a host of eager solar observers. Looking directly at the Sun is EXTREMELY hazardous. But many astronomers, both professional and amateur, have found ways to view the Sun safely to learn about it. You, too, can view the Sun in all of its glorious detail. Some of the newest, most exciting telescopes on the market are affordable to amateur astronomers or even just curious sky watchers, and with this guide to what the Sun has to offer, including sunspots, prominences, and flares, plus reviews of the latest instruments for seeing and capturing images of the Sun, you can contribute to humankind’s knowledge of this immense ball of glowing gases that gives us all life. For a complete guide to Sun viewing, see also Total Solar Eclipses and How to Observe Them (2007) by Martin Mobberley in this same series.

  7. Sun-synchronous satellite orbit determination

    Science.gov (United States)

    Ma, Der-Ming; Zhai, Shen-You

    2004-02-01

    The linearized dynamic equations used for on-board orbit determination of Sun-synchronous satellite are derived. Sun-synchronous orbits are orbits with the secular rate of the right ascension of the ascending node equal to the right ascension rate of the mean sun. Therefore the orbit is no more a closed circle but a tight helix about the Earth. In the paper, instead of treating the orbit as a closed circle, the actual helix orbit is taken as nominal trajectory. The details of the linearized equations of motion for the satellite in the Sun-synchronous orbit are derived. The linearized equations are obtained by perturbing the Keplerian motion with the J2 correction and the effect of sun's attraction being neglected. Combined with the GPS navigation equations, the Kalman filter formulation is given. The particular application considered is the circular Sun-synchronous orbit with the altitude of 800 km and inclination of 98.6°. The numerical example simulated by MATLAB® shows that only the pseudo-range data used in the algorithm still gives acceptable results. Based on the simulation results, we can use the on-board GPS receivers' signal only as an alternative to determine the orbit of Sun-Synchronous satellite and therefore circumvents the need for extensive ground support.

  8. SunPy—Python for solar physics

    Science.gov (United States)

    SunPy Community; Mumford, Stuart J.; Christe, Steven; Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew R.; Liedtke, Simon; Hewett, Russell J.; Mayer, Florian; Hughitt, Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M.; Malocha, Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J.; Robitaille, Thomas P.; Mampaey, Benjamin; Campos-Rozo, Jose Iván; Kirk, Michael S.

    2015-01-01

    This paper presents SunPy (version 0.5), a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation (NumPy, SciPy) and machine learning (scikit-learn) to visualization and plotting (matplotlib). SunPy is a data-analysis environment specializing in providing the software necessary to analyse solar and heliospheric data in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from missions such as GOES, SDO/EVE, and PROBA2/LYRA, and radio spectra from e-Callisto and STEREO/SWAVES. We describe SunPy's functionality, provide examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  9. Anisotropic microstructure near the sun

    Science.gov (United States)

    Coles, W. A.; Grall, R. R.; Spangler, S. R.; Sakurai, T.; Harmon, J. K.

    1996-07-01

    Radio scattering observations provide a means of measuring a two-dimensional projection of the three-dimensional spatial spectrum of electron density, i.e., in the plane perpendicular to the line of sight. Earlier observations have shown that the microstructure at scales of the order of 10 km becomes highly field-aligned inside of 10 Rsolar [Armstrong et al., 1990]. Earlier work has also shown that density fluctuations at scales larger than 1000 km have a Kolmogorov spectrum, whereas the smaller scale structure has a flatter spectrum and is considerably enhanced above the Kolmogorov ``background'' [Coles et al., 1991]. Here we present new observations made during 1990 and 1992. These confirm the earlier work, which was restricted to one source on a few days, but they suggest that the anisotropy changes abruptly near 6 Rsolar which was not clear in the earlier data. The axial ratio measurements are shown on Figure 1 below. The new observations were made with a more uniform sampling of the spatial plane. They show that contours of constant correlation are elliptical. This is apparently inconsistent with the spatial correlation of the ISEE-3 magnetic field which shows a ``Maltese Cross'' shape [Matthaeus et al., 1990]. However this inconsistency may be only apparent: the magnetic field and density correlations need not have the same shape; the scale of the magnetic field correlations is at least 4 orders of magnitude larger; they are much further from the sun; and they are point measurements whereas ours are path-integrated. We also made two simultaneous measurements, at 10 Rsolar, of the anisotropy on scales of 200 to 4000 km. Significant anisotropy was seen on the smaller scales, but the larger scale structure was essentially isotropic. This suggests that the process responsible for the anisotropic microstructure is independent of the larger scale isotropic turbulence. It is then tempting to speculate that the damping of this anisotropic process inside of 6 Rsolar

  10. The Sun's dusty interstellar environment

    Science.gov (United States)

    Sterken, Veerle

    2016-07-01

    The Sun's dusty interstellar environment Interstellar dust from our immediate interstellar neighborhood travels through the solar system at speeds of ca. 26 km/s: the relative speed of the solar system with respect to the local interstellar cloud. On its way, its trajectories are altered by several forces like the solar radiation pressure force and Lorentz force. The latter is due to the charged dust particles that fly through the interplanetary magnetic field. These trajectories differ per particle type and size and lead to varying fluxes and directions of the flow inside of the solar system that depend on location but also on phase in the solar cycle. Hence, these fluxes and directions depend strongly on the configuration of the inner regions and outer regions of the heliosphere. Several missions have measured this dust in the solar system directly. The Ulysses dust detector data encompasses 16 years of intestellar dust fluxes and approximate directions, Stardust captured returned to Earth a few of these particles sucessfully, and finally the Cassini dust detector allowed for compositional information to be obtained from the impacts on the instrument. In this talk, we give an overview of the current status of interstellar dust research through the measurements made inside of the solar system, and we put them in perspective to the knowledge obtained from more classical astronomical means. In special, we focus on the interaction of the dust with the interplanetary magnetic field, and on what we learn about the dust (and the fields) by comparing the available dust data to computer simulations of dust trajectories. Finally, we synthesize the different methods of observation, their results, and give a preview on new research opportunities in the coming year(s).

  11. Perspectives on the Interior of the Sun

    Indian Academy of Sciences (India)

    S. Μ. Chitre

    2000-09-01

    The interior of the Sun is not directly accessible to observations. Nonetheless, it is possible to infer the physical conditions inside the Sun with the help of structure equations governing its equilibrium and with the powerful observational tools provided by the neutrino fluxes and oscillation frequencies. The helioseismic data show that the internal constitution of the Sun can be adequately represented by a standard solar model. It turns out that a cooler solar core is not a viable solution for the measured deficit of neutrino fluxes, and the resolution of the solar neutrino puzzle should be sought in the realm of particle physics.

  12. The Jovian period in the Sun?

    Science.gov (United States)

    Kotov, V. A.

    2015-09-01

    The 41-year measurements of the Doppler effect of the photosphere performed at the Crimean Astrophysical Observatory, discovered two periods of global oscillations of the Sun: 9600.606(12) s and 9597.929(15) s. Their beat period, 398.4(2.9) d, well agrees with a synodic orbital period of Jupiter, PJ = 398.9 d, raising a new problem for solar physics, cosmogony and cosmology. A hypothesis is advanced that the PJ beating of the Sun is induced by gravitation of Jupiter, revolving in a privileged reference system "the Sun - the Earth".

  13. Semiautomatic sun shots with the WIDIF DIflux

    Science.gov (United States)

    Rasson, Jean L.; Hendrickx, Olivier; Marin, Jean-Luc

    2017-07-01

    The determination of magnetic declination angle entails finding two directions: geographic north and magnetic north. This paper deals with the former. The known way to do it by using the sun's calculable orientation in the sky is improved by using a device based on a WIDIF DIflux theodolite and split photocells positioned on its telescope ocular. Given the WIDIF accurate timing and location provided by the onboard GPS receiver, an astronomical computation can be effected to accurately and quickly determine the sun's azimuth and an auxiliary mark's azimuth. The precise sun's crossing of the split photocell, amplified by the telescope's magnification, allows azimuth accuracies of a few seconds of arc.

  14. Finding the lost siblings of the Sun

    Science.gov (United States)

    Liu, Cheng; Feltzing, Sofia; Ruchti, Gregory

    2014-01-01

    We have performed a spectral analysis on 18 stars solar sibling candidate. We found that only one one of the candidateshas solar metallicity and at the same time might have an age comparable to that of the Sun.

  15. Sun and Other Types of Radiation

    Science.gov (United States)

    ... What Causes Cancer? Sun and Other Types of Radiation Learn about the different types of radiation and ... other diseases. Learn more here. Other Types of Radiation Exposure Not all types of radiation have been ...

  16. Sun behaviour after cutaneous malignant melanoma

    DEFF Research Database (Denmark)

    Idorn, L W; Datta, P; Heydenreich, J

    2013-01-01

    Background  It has been reported that patients with cutaneous malignant melanoma (CMM) can lower their risk of a second primary melanoma by limiting recreational sun exposure. Previous studies based on questionnaires and objective surrogate measurements indicate that before their diagnosis......, patients with CMM are exposed to higher ultraviolet radiation (UVR) doses than controls, followed by a reduction after diagnosis. Objectives  In a prospective, observational case-control study, we aimed to assess sun exposure after diagnosis of CMM by objective measurements to substantiate advice about sun...... months and 6 years before the start of the study. During a summer season participants filled in sun exposure diaries daily and wore personal electronic UVR dosimeters in a wristwatch that continuously measured time-stamped UVR doses in standard erythema dose. Results  The UVR dose of recently diagnosed...

  17. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  18. Nilaja Sun's "No Child...": Reflections on Success

    Science.gov (United States)

    Sun, Nilaja; Alexander, Phillip; Huldeen, Branden; Russell, Ron; Friedman, Melissa

    2007-01-01

    This article describes Nilaja Sun's groundbreaking one-woman show about a TA, her students, and her school, and includes interviews with the author/performer, an excerpt of the work, and a discussion of the organization behind it.

  19. Sensor-controlled heliostat with an equatorial mount

    Energy Technology Data Exchange (ETDEWEB)

    Aiuchi, Kosuke; Yoshida, Kazuo; Onozaki, Masaki; Katayama, Yukuo [The Institute of Applied Energy, Tokyo (Japan); Nakamura, Minoru; Nakamura, Katsushige [Mitaka Kohki Co. Ltd., Tokyo (Japan)

    2006-09-15

    A heliostat having a photo-sensor sun-tracking system was developed and evaluated. The sensor was composed of a set of two photo-cells placed side by side on the bottom of the small box. Sun-tracking can be achieved by rotating the heliostat equipped with the sensor, while maintaining the two photo-cells under illumination by the sun through a slit in the box. A preliminary tracking evaluation of the sensor was carried out with the aid of a mirror-telescope system, and the tracking error was estimated to be less than 0.6mrad in clear weather. The developed heliostat employed an equatorial mount system that permits the rotating speed of the right-ascension axis to be nearly constant for the diurnal motion of the sun. The use of two additional sensors, a cloud sensor and a primary sensor, permitted stable tracking with high accuracy even in a cloudy sky. Field tests of the heliostat revealed that an angular error within 2mrad was achieved in fine weather. In cloudy weather, the heliostat operated stably with the cloud sensor within an error of 10mrad. (author)

  20. A CMOS image sensor with row and column profiling means

    NARCIS (Netherlands)

    Xie, N.; Theuwissen, A.J.P.; Wang, X.; Leijtens, J.A.P.; Hakkesteegt, H.; Jansen, H.

    2008-01-01

    This paper describes the implementation and firstmeasurement results of a new way that obtains row and column profile data from a CMOS Image Sensor, which is developed for a micro-Digital Sun Sensor (μDSS).The basic profiling action is achieved by the pixels with p-type MOS transistors which realize

  1. The Sun murrab Baltimaadesse ja Soome

    Index Scriptorium Estoniae

    2008-01-01

    Aprillis andis ansambel Tanel Padar & The Sun Soomes, Lätis, Leedus ja Eestis üksteist kontserti. Heliplaadi "Here Gomes The Sun" lugu "Hopelessness You" on Soome raadiote tipp 300s neljakümnendal kohal, lugu "Learn the game" on Leedu FM99 raadios 33 enim mängitava loo seas, laul "One of those days" saavutas Läti raadio SWH rokkmuusika edetabelis teise koha.

  2. Optimal control of sun tracking solar concentrators

    Science.gov (United States)

    Hughes, R. O.

    1979-01-01

    Application of the modern control theory to derive an optimal sun tracking control for a point focusing solar concentrator is presented. A standard tracking problem converted to regulator problem using a sun rate input achieves an almost zero steady state tracking error with the optimal control formulation. However, these control techniques are costly because optimal type algorithms require large computing systems, thus they will be used mainly as comparison standards for other types of control algorithms and help in their development.

  3. The Sun murrab Baltimaadesse ja Soome

    Index Scriptorium Estoniae

    2008-01-01

    Aprillis andis ansambel Tanel Padar & The Sun Soomes, Lätis, Leedus ja Eestis üksteist kontserti. Heliplaadi "Here Gomes The Sun" lugu "Hopelessness You" on Soome raadiote tipp 300s neljakümnendal kohal, lugu "Learn the game" on Leedu FM99 raadios 33 enim mängitava loo seas, laul "One of those days" saavutas Läti raadio SWH rokkmuusika edetabelis teise koha.

  4. The vectorial photoelectric effect under solar irradiance and its application to sun sensing

    CERN Document Server

    Hechenblaikner, Gerald

    2014-01-01

    Sun sensors are an integral part of the attitude and orbit control system onboard almost any spacecraft. While the majority of standard analogue sun sensors is based on photo-detectors which produce photo-currents proportional to the cosine of the incidence angle (cosine detectors), we propose an alternative scheme where the vectorial photoelectric effect is exploited to achieve a higher sensitivity of the sensed photo-current to the incidence angle. The vectorial photo-effect is investigated in detail for metal cathode detectors in a space environment. Besides long operational lifetimes without significant degradation, metal cathode detectors are insensitive to earth albedo, which may significantly reduce the errors affecting attitude measurements in low earth orbits. Sensitivity curves are calculated and trade-offs performed with the aim of optimizing the sensitivity whilst also providing currents sufficient for detection. Simple applications and detector configurations are also discussed and compared to ex...

  5. How to Observe the Sun Safely

    CERN Document Server

    Macdonald, Lee

    2012-01-01

    How to Observe the Sun Safely, Second Edition gives all the basic information and advice the amateur astronomer needs to get started in observing our own ever-fascinating star. Unlike many other astronomical objects, you do not need a large telescope or expensive equipment to observe the Sun. And it is possible to take excellent pictures of the Sun with today's low-cost digital cameras! This book surveys what is visible on the Sun and then describes how to record solar features and measure solar activity levels. There is also an account of how to use H-alpha and Calcium-K filters to observe and record prominences and other features of the solar chromosphere, the Sun's inner atmosphere. Because we are just entering a period of high activity on the Sun, following a long, quiet period, this is a great time to get involved with solar observing. Still emphasizing safety first, this Second Edition reflects recent and exciting advances in solar observing equipment. Chapters 6 through 8 have been completely revised ...

  6. Orientation in birds. The sun compass.

    Science.gov (United States)

    Schmidt-Koenig, K; Ganzhorn, J U; Ranvaud, R

    1991-01-01

    The sun compass was discovered by G. Kramer in caged birds showing migratory restlessness. Subsequent experiments with caged birds employing directional training and clock shifts, carried out by Hoffman and Schmidt-Koenig, showed that the sun azimuth is used, and the sun altitude ignored. In the laboratory, McDonald found the accuracy to be +/- 3 degrees(-)+/- 5 degrees. According to Hoffmann and Schmidt-Koenig, caged birds trained at medium northern latitudes were able to allow for the sun's apparent movement north of the arctic circle, but not in equatorial and trans-equatorial latitudes. In homing experiments, and employing clock shifts, Schmidt-Koenig demonstrated that the sun compass is used by homing pigeons during initial orientation. This finding is the principal evidence for the existence of a map-and-compass navigational system. Pigeons living in equatorial latitudes utilize the sun compass even under the extreme solar conditions of equinox, achieving angular resolution of about 3 degrees in homing experiments. According to preliminary analyses, the homing pigeons' ephemerides are retarded by several weeks (Ranvaud, Schmidt-Koenig, Ganzhorn et al.).

  7. SunPy: Solar Physics in Python

    Science.gov (United States)

    Ryan, Daniel; Christe, Steven; Mumford, Stuart; Perez Suarez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon; Hewett, Russel

    2015-04-01

    SunPy is a community-developed open-source software library for solar physics. It is written in Python, a free, cross-platform, general-purpose, high-level programming language which is being increasingly adopted throughout the scientific community as well as further afield. This has resulted in a wide array of software packages useful for scientific computing, from numerical computation (NumPy, SciPy, etc.), to machine learning (scifitlearn), to visualization and plotting (matplotlib). SunPy aims to provide required specialised software for analysing solar and heliospheric datasets in Python. The current version is 0.5 with 0.6 expected to be released later this year. SunPy provides solar data access through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It supports common data types from major solar missions such as images (SDO/AIA, STEREO, PROBA2/SWAP etc.), time series (GOES/XRS, SDO/EVE, PROBA2/LYRA), and radio spectra (e-Callisto, STEREO/WAVES). SunPy’s code base is publicly available through github.com and can be contributed to by anyone. In this poster we demonstrate SunPy’s functionality and future goals of the project. We also encourage interested users to become involved in further developing SunPy.

  8. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under th

  9. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under

  10. Picosecond to second dynamics reveals a structural transition in Clostridium botulinum NO-sensor triggered by the activator BAY-41-2272.

    Science.gov (United States)

    Yoo, Byung-Kuk; Lamarre, Isabelle; Rappaport, Fabrice; Nioche, Pierre; Raman, C S; Martin, Jean-Louis; Negrerie, Michel

    2012-12-21

    Soluble guanylate cyclase (sGC) is the mammalian endogenous nitric oxide (NO) receptor that synthesizes cGMP upon NO activation. In synergy with the artificial allosteric effector BAY 41-2272 (a lead compound for drug design in cardiovascular treatment), sGC can also be activated by carbon monoxide (CO), but the structural basis for this synergistic effect are unknown. We recorded in the unusually broad time range from 1 ps to 1 s the dynamics of the interaction of CO binding to full length sGC, to the isolated sGC heme domain β(1)(200) and to the homologous bacterial NO-sensor from Clostridium botulinum. By identifying all phases of CO binding in this full time range and characterizing how these phases are modified by BAY 41-2272, we show that this activator induces the same structural changes in both proteins. This result demonstrates that the BAY 41-2272 binding site resides in the β(1)(200) sGC heme domain and is the same in sGC and in the NO-sensor from Clostridium botulinum.

  11. The sun and space weather Second Edition

    CERN Document Server

    Hanslmeier, Arnold

    2007-01-01

    This second edition is a great enhancement of literature which will help the reader get deeper into the specific topics. There are new sections included such as space weather data sources and examples, new satellite missions, and the latest results. At the end a comprehensive index is given which will allow the reader to quickly find his topics of interest. The Sun and Space weather are two rapidly evolving topics. The importance of the Sun for the Earth, life on Earth, climate and weather processes was recognized long ago by the ancients. Now, for the first time there is a continuous surveillance of solar activity at nearly all wavelengths. These data can be used to improve our understanding of the complex Sun-Earth interaction. The first chapters of the book deal with the Sun as a star and its activity phenomena as well as its activity cycle in order to understand the complex physics of the Sun-Earth system. The reader will see that there are many phenomena but still no definite explanations and models exis...

  12. The Sun Sense Study: An Intervention to Improve Sun Protection in Children

    Science.gov (United States)

    Glasser, Alice; Shaheen, Magda; Glenn, Beth A.; Bastani, Roshan

    2010-01-01

    Objectives: To assess the effect of a multicomponent intervention on parental knowledge, sun avoidance behaviors, and sun protection practices in children 3-10 years. Methods: A randomized trial at a pediatric clinic recruited 197 caregiver-child pairs (90% parents). Intervention included a brief presentation and brochure for the parent and…

  13. After the Bell: Developing Sun Sense--Learning about Protection from the Sun's Rays

    Science.gov (United States)

    Farenga, Stephen J.; Ness, Daniel

    2008-01-01

    The American Academy of Dermatology (2008) reports that our students will experience 80% of their lifetime exposure to the Sun by the time they are 18. Further, research has demonstrated that continued exposure to the Sun's ultraviolet rays can lead to skin aging, sunburn, immune suppression, ocular melanoma, cataracts, corneal burns, and even…

  14. Sound-speed inversion of the Sun using a nonlocal statistical convection theory

    CERN Document Server

    Zhang, Chunguang; Xiong, Darun; Christensen-Dalsgaard, Jørgen; 10.1088/2041-8205/759/1/L14

    2012-01-01

    Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior; and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

  15. 77 FR 34122 - Application of Sun Air Express, LLC, d/b/a Sun Air International for Commuter Authority

    Science.gov (United States)

    2012-06-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Office of the Secretary Application of Sun Air Express, LLC, d/b/a Sun Air International for Commuter... to show cause why it should not issue an order finding Sun Air Express, LLC d/b/a Sun...

  16. A sun holiday is a sunburn holiday

    DEFF Research Database (Denmark)

    Petersen, Bibi; Thieden, Elisabeth; Philipsen, Peter Alshede

    2013-01-01

    Many people take holidays in sunny locations with the express aim of sunbathing. This may result in sunburn, which is a risk factor for skin cancer. We investigated 25 Danish sun seekers during a week's holiday in the Canary Islands. The percentage of body surface area with sunburn was determined......-specific UVR doses after adjustment for sun protection factor. Remarkably, we found that all volunteers sunburned at some point. The risk of sunburn correlated significantly with the adjusted body site-specific UVR dose. Furthermore, there was also a significant relationship between the daily UVR dose...... and percentage of body surface area with sunburn. Our study shows that holiday UVR exposure results in a high risk of sunburn, which potentially increases the risk of skin cancer. Possible protection by melanogenesis is insufficient to protect against sunburn during a 1-week sun holiday. Finally, our data...

  17. Precise nuclear physics for the sun

    Energy Technology Data Exchange (ETDEWEB)

    Bemmerer, Daniel

    2012-07-01

    For many centuries, the study of the Sun has been an important testbed for understanding stars that are further away. One of the first astronomical observations Galileo Galilei made in 1612 with the newly invented telescope concerned the sunspots, and in 1814, Joseph von Fraunhofer employed his new spectroscope to discover the absorption lines in the solar spectrum that are now named after him. Even though more refined and new modes of observation are now available than in the days of Galileo and Fraunhofer, the study of the Sun is still high on the agenda of contemporary science, due to three guiding interests. The first is connected to the ages-old human striving to understand the structure of the larger world surrounding us. Modern telescopes, some of them even based outside the Earth's atmosphere in space, have succeeded in observing astronomical objects that are billions of light-years away. However, for practical reasons precision data that are important for understanding stars can still only be gained from the Sun. In a sense, the observations of far-away astronomical objects thus call for a more precise study of the closeby, of the Sun, for their interpretation. The second interest stems from the human desire to understand the essence of the world, in particular the elementary particles of which it consists. Large accelerators have been constructed to produce and collide these particles. However, man-made machines can never be as luminous as the Sun when it comes to producing particles. Solar neutrinos have thus served not only as an astronomical tool to understand the Sun's inner workings, but their behavior on the way from the Sun to the Earth is also being studied with the aim to understand their nature and interactions. The third interest is strictly connected to life on Earth. A multitude of research has shown that even relatively slight changes in the Earth's climate may strongly affect the living conditions in a number of densely

  18. Neptune as a Mirror for the Sun

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    How would the Kepler mission see a star like the Sun? We now know the answer to this question due to a creative approach: a new study has used the Kepler K2 mission to detect signals from the Sun reflected off of the surface of Neptune.Asteroseismology uses different oscillation modes of a star to probe its internal structure and properties. [Tosaka]Information in OscillationsKeplers most glamorous work is in discovering new planets around other stars. To successfully do this, however, the spacecraft is also quietly doing a lot of very useful work in the background, characterizing the many stars in our vicinity that planets might be found around.One of the ways Kepler gets information about these stars is from oscillations of the stars intensities. In asteroseismology, we look at oscillatory modes that are caused by convection-driven pressure changes on the inside of the star. All stars with near-surface convection oscillate like this including the Sun and by measuring the oscillations in intensity of these stars, we can make inferences about the stars properties.A Planetary MirrorWe do this by first understanding our Suns oscillations especially well (made easier by the fact that its nearby!). Then we use asteroseimic scaling relations determined empirically that relate characteristics like mass and radius of other stars to those of the Sun, based on the relation between the stars oscillation properties to the Suns.The trouble is, those oscillation properties are difficult to measure, and different instruments often measure different values. For this reason, wed like to measure the Suns oscillations with the same instrument we use to measure other stars oscillations: Kepler.Top panel: Kepler K2 49-day light curve of Neptune. Bottom panel: power density spectrum as a function of frequency (grey). Neptunes rotation frequencies and harmonics appear toward the left side (blue); the excess power due to the solar modes is visible toward the bottom right. The green curve

  19. The Spectrum of Darkonium in the Sun

    CERN Document Server

    Kouvaris, Chris; Nielsen, Niklas Grønlund

    2016-01-01

    Dark matter that gets captured in the Sun may form positronium-like bound states if it self-interacts via light dark photons. In this case, dark matter can either annihilate to dark photons or recombine in bound states which subsequently also decay to dark photons. The fraction of the dark photons that leave the Sun without decaying to Standard Model particles have a characteristic energy spectrum which is a mixture of the direct annihilation process, the decays of ortho- and para- bound states and the recombination process. The ultimate decay of these dark photons to positron-electron pairs (via kinetic mixing) outside the Sun creates a distinct signal that can either identify or set strict constraints on dark photon models.

  20. The spectrum of darkonium in the Sun

    Science.gov (United States)

    Kouvaris, Chris; Langæble, Kasper; Grønlund Nielsen, Niklas

    2016-10-01

    Dark matter that gets captured in the Sun may form positronium-like bound states if it self-interacts via light dark photons. In this case, dark matter can either annihilate to dark photons or recombine in bound states which subsequently also decay to dark photons. The fraction of the dark photons that leave the Sun without decaying to Standard Model particles have a characteristic energy spectrum which is a mixture of the direct annihilation process, the decays of ortho- and para- bound states and the recombination process. The ultimate decay of these dark photons to positron-electron pairs (via kinetic mixing) outside the Sun creates a distinct signal that can either identify or set strict constraints on dark photon models.

  1. The sun since the Bronze Age

    Science.gov (United States)

    Eddy, J. A.

    1976-01-01

    An investigation is conducted concerning the behavior of the sun during the last 7000 years. The C-14 content in carbonaceous fossil material can be used as an indicator regarding the level of solar activity at the time when the carbon was assimilated in the process of photosynthesis. Living trees, such as the bristlecone pine, provide a solar activity record to about 3000 B.C. The record can be extended with the aid of well-preserved dead wood to beyond 5000 B.C. The results of an analysis of solar activity levels as a function of time on the basis of C-14 contents are presented in a graph. Attention is given to the Maunder Minimum, a history of the sun in the last 5000 years, an interpretation of the major C-14 excursions, and the sun and climate history.

  2. 'My Sun' and 'Guided by the Moon'

    Directory of Open Access Journals (Sweden)

    Rebecca Baillie

    2013-07-01

    Full Text Available My Sun and Guided by the Moon (2012 show the heavily pregnant artist with her swollen belly covered in gold and silver leaf. The work is suggestive that the connectivity experienced by an expectant mother, extends outwards, even as far as her relationship with the cosmos. The 'sun' portrait was taken on a bright September morning, and its partner image, the following October, on the night of a full moon. Female cycles and the importance of time passing during a pregnancy are referenced. Interestingly, bearing in mind that the artist gave birth to a son in November, creating the 'moon' portrait felt like a familiar, empowering and yet isolated expression of selfhood, whilst the 'sun/son' version exuded the energy of a collaboration, and stimulated feelings of joy, liberation and potentiality. By seeming contradiction, the boy was born on a full moon, exactly a month to the day that Guided by the Moon was taken.

  3. Semiautomatic sun shots with the WIDIF DIflux

    Directory of Open Access Journals (Sweden)

    J. L. Rasson

    2017-07-01

    Full Text Available The determination of magnetic declination angle entails finding two directions: geographic north and magnetic north. This paper deals with the former. The known way to do it by using the sun's calculable orientation in the sky is improved by using a device based on a WIDIF DIflux theodolite and split photocells positioned on its telescope ocular. Given the WIDIF accurate timing and location provided by the onboard GPS receiver, an astronomical computation can be effected to accurately and quickly determine the sun's azimuth and an auxiliary mark's azimuth. The precise sun's crossing of the split photocell, amplified by the telescope's magnification, allows azimuth accuracies of a few seconds of arc.

  4. Use of environmental impacts in sensor scheduling

    Science.gov (United States)

    Shea, Peter J.; Gioioso, Marisa; Snell, Hilary E.

    2010-04-01

    Current surveillance systems operate in a highly dynamic environment in which large numbers of sensors on board multiple platforms must cooperate in order to achieve overall mission success. In an attempt to maximize sensor performance, today's sensors employ rudimentary or, in some cases, inflexible sensor tasking schemes. These approaches are highly tuned to a specific scenario and geometry and are inflexible to changes in the mission, environmental conditions, heterogeneous sensors, and different system architectures. As the complexity of the problem space increases and new sensors become available, it is critical to have a sensor management scheme that is capable of incorporating new environmental knowledge, new sensors and different systems approaches with minimal computational impact on the overall system. Each system should develop an autonomous sensor tasking capability which factors in global concerns within the complete distributed network of platforms and sensors. Moreover, tasking efficiency can be improved by a highly developed understanding of sensor performance at each point in time. This can be achieved by incorporating the impact of problem geometry - sensor location, track object type and view angle - and weather phenomena, such as clouds, aerosols, turbulence and sun glint. This paper describes our approach for simultaneously optimizing sensor resource management, surveillance objectives, and atmospheric transmission of signals while minimizing sensor and environmental noise. Our approach uses a genetic algorithm to evolve a population of sensor tasking assignments through constantly-updating track locations, weather conditions, and lighting conditions. Preliminary studies demonstrate encouraging improvements in sensor management performance. We will present results from our preliminary studies and discuss a path forward for our technology.

  5. Magnetic Evolution and the Disappearance of Sun-Like Activity Cycles

    Science.gov (United States)

    Metcalfe, Travis S.; van Saders, Jennifer

    2017-09-01

    After decades of effort, the solar activity cycle is exceptionally well characterized, but it remains poorly understood. Pioneering work at the Mount Wilson Observatory demonstrated that other Sun-like stars also show regular activity cycles, and suggested two possible relationships between the rotation rate and the length of the cycle. Neither of these relationships correctly describes the properties of the Sun, a peculiarity that demands explanation. Recent discoveries have started to shed light on this issue, suggesting that the Sun's rotation rate and magnetic field are currently in a transitional phase that occurs in all middle-aged stars. Motivated by these developments, we identify the manifestation of this magnetic transition in the best available data on stellar cycles. We propose a reinterpretation of previously published observations to suggest that the solar cycle may be growing longer on stellar evolutionary timescales, and that the cycle might disappear sometime in the next 0.8 - 2.4 Gyr. Future tests of this hypothesis will come from ground-based activity monitoring of Kepler targets that span the magnetic transition, and from asteroseismology with the Transiting Exoplanet Survey Satellite (TESS) mission to determine precise masses and ages for bright stars with known cycles.

  6. The sun and heliosphere at solar maximum.

    Science.gov (United States)

    Smith, E J; Marsden, R G; Balogh, A; Gloeckler, G; Geiss, J; McComas, D J; McKibben, R B; MacDowall, R J; Lanzerotti, L J; Krupp, N; Krueger, H; Landgraf, M

    2003-11-14

    Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.

  7. Ra: The Sun for Science and Humanity

    Science.gov (United States)

    1996-01-01

    To guide the development of the Ra Strategic Framework, we defined scientific and applications objectives. For our primary areas of scientific interest, we choose the corona, the solar wind, the Sun's effect on the Earth, and solar theory and model development. For secondary areas of scientific interest, we selected sunspots, the solar constant, the Sun's gravitational field, helioseismology and the galactic cosmic rays. We stress the importance of stereoscopic imaging, observations at high spatial, spectral, and temporal resolutions, as well as of long duration measurements. Further exploration of the Sun's polar regions is also important, as shown already by the Ulysses mission. From an applications perspective, we adopted three broad objectives that would derive complementary inputs for the Strategic Framework. These were to identify and investigate: possible application spin-offs from science missions, possible solar-terrestrial missions dedicated to a particular application, and possible future applications that require technology development. The Sun can be viewed as both a source of resources and of threats. Our principal applications focus was that of threat mitigation, by examining ways to improve solar threat monitoring and early warning systems. We compared these objectives to the mission objectives of past, current, and planned international solar missions. Past missions (1962-1980) seem to have been focused on improvement of scientific knowledge, using multiple instrument spacecraft. A ten year gap followed this period, during which the results from previous missions were analyzed and solar study programmes were prepared in international organizations. Current missions (1990-1996) focus on particular topics such as the corona, solar flares, and coronal mass ejections. In planned missions, Sun/Earth interactions and environmental effects of solar activity are becoming more important. The corona is the centre of interest of almost all planned missions

  8. Haloes around the Moon and the Sun

    Science.gov (United States)

    Gaina, Alex; Gaina, Danielle A.

    2008-10-01

    The authors observations of the Haloes around the Moon and the Sun during few last years are reported. A Historical review of the phenomenon is given since the observations by Benvenuto Cellini and Gaston Tissandier is given. A photograph (from eight available) of the Halo around the Sun observed in Chisinau on 21 May 2007 is included. The Halo from 21 May 2007 occured after a very fast increasing of the air temperature during one day by more than 15 Deg. The authors consider, that the phenomenon is due to scattering of light on Cirri clouds(7 km altitude), present on the sky during that day. They formed due to very fast heating.

  9. SunShot Initiative Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    DOE Solar Energy Technologies Office

    2015-04-01

    The U.S. Department of Energy (DOE) SunShot Initiative is a collaborative national effort launched in 2011 that aggressively drives innovation to make solar energy fully cost competitive with traditional energy sources before the end of the decade. The SunShot fact sheet outlines goals and successes of the program as it works with private companies, universities, non-profit organizations, state and local governments, and national laboratories to drive down the cost of solar electricity to $0.06 per kilowatt-hour, without incentives, by the year 2020.

  10. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  11. Sun-Earth Day: Growth and Impact of NASA E/PO Program

    Science.gov (United States)

    Hawkins, I.; Thieman, J.

    2004-12-01

    Over the past six years, the NASA Sun-Earth Connection Education Forum has sponsored and coordinated education public outreach events to highlight NASA Sun-Earth Connection research and discoveries. Our strategy involves using celestial phenomena, such as total solar eclipses and the Transit of Venus to celebrate Sun-Earth Day, a popular Education and Public Outreach international program. Sun-Earth Day also focuses attention on Equinoxes and Solstices to engage K-12 schools and the general public in space science activities, demonstrations, and interactions with space scientists. In collaboration with partners that include the Exploratorium, Maryland Science Center, NASA Connect, Sun-Earth Connection missions, Ideum, and others, we produce webcasts, other multi-media, and print resources for use by school and informal educators nation-wide. We provide training and professional development to K-12 educators, museum personnel, amateur astronomers, Girl Scout leaders, etc., so they can implement their own outreach programs taking advantage of our resources. A coordinated approach promotes multiple programs occurring each year under a common theme. We will report lessons learned from several years of experience, and strategies for growth and sustainability. We will also share our plans for "Ancient Observatories - Timeless Knowledge" our theme for Sun-Earth Day 2005, which will feature solar alignments at ancient sites that mark the equinoxes and/or solstices. The video and webcast programming will feature several sites including: Chaco Canyon (New Mexico), Hovenweep (Utah), and Chichen Itza (Mexico). Many of these sites present unique opportunities to develop authentic cultural connections to Native Americans, highlighting the importance of the Sun across the ages.

  12. Metamaterial Sensors

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2013-01-01

    Full Text Available Metamaterials have attracted a great deal of attention due to their intriguing properties, as well as the large potential applications for designing functional devices. In this paper, we review the current status of metamaterial sensors, with an emphasis on the evanescent wave amplification and the accompanying local field enhancement characteristics. Examples of the sensors are given to illustrate the principle and the performance of the metamaterial sensor. The paper concludes with an optimistic outlook regarding the future of metamaterial sensor.

  13. BcSUN1, a B. cinerea SUN-Family Protein, Is Involved in Virulence

    Science.gov (United States)

    Pérez-Hernández, Alicia; González, Mario; González, Celedonio; van Kan, Jan A. L.; Brito, Nélida

    2017-01-01

    BcSUN1 is a glycoprotein secreted by Botrytis cinerea, an important plant pathogen that causes severe losses in agriculture worldwide. In this work, the role of BcSUN1 in different aspects of the B. cinerea biology was studied by phenotypic analysis of Bcsun1 knockout strains. We identified BcSUN1 as the only member of the Group-I SUN family of proteins encoded in the B. cinerea genome, which is expressed both in axenic culture and during infection. BcSUN1 is also weakly attached to the cellular surface and is involved in maintaining the structure of the cell wall and/or the extracellular matrix. Disruption of the Bcsun1 gene produces different cell surface alterations affecting the production of reproductive structures and adhesion to plant surface, therefore reducing B. cinerea virulence. BcSUN1 is the first member of the SUN family reported to be involved in the pathogenesis of a filamentous fungus. PMID:28163701

  14. Sun exposure and sun protection practices of children and their parents.

    LENUS (Irish Health Repository)

    Kiely, A D

    2009-05-01

    The primary aims of this study were: to estimate sun exposure in hours of children in Cork during the summer months; to examine sun protection measures used by children and their parents and to explore parental knowledge of sun exposure and protection. A cross-sectional study, using a semi-structured questionnaire, was conducted in June 2006 in primary schools, pre-schools and creches throughout Cork City and County. Parents of 250 children aged less than 12 years were sampled. Mean sun exposure of Cork children was 40.9 hours per week in the summer months, with 77 (46.1%) children developing sunburn. 59.3% of the studied children were of skin type 1 or 2. 95 (57%) children on weekdays and 137 (82%) children at weekends were exposed to the sun between 11 am and 3 pm. Sunscreen and hats\\/caps were the most common protection measures used. A minority used protective clothing, sunglasses or sought shade. Thirty one (30.5%) children had sunscreen reapplied every 2 hours. Knowledge of sun protection was considerable among Irish parents. However the frequency of sunburn among Irish children suggests we are not providing them with adequate sun protection.

  15. Wet Process Induced Phase Transited Drug Delivery System as a ...

    African Journals Online (AJOL)

    Nx 6110

    effect of varying osmotic pressure of the dissolution medium on drug release was studied. ... results of in vivo toxicity studies may support the use of phase transited ... ocular inflammatory conditions [16]. ... Flurbiprofen was obtained from Sun.

  16. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built us

  17. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built us

  18. Rational SU(N) Gaudin Model

    Institute of Scientific and Technical Information of China (English)

    曹俊鹏; 侯伯宇; 岳瑞宏

    2001-01-01

    We propose the eigenstates and eigenvalues of Hamiltonians of the rational SU(N) Gaudin model based onthe quasi-classical limit of the SU ( N) chain under the periodic boundary condition. Using the quantum inversescattering method, we also obtain the eigenvalues of the generation function of the rational SU ( N) Gaudin model.

  19. Asymmetric dark matter and the Sun

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Sarkar, Subir

    2010-01-01

    Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure...

  20. SunPy - Python for Solar Physics

    CERN Document Server

    Community, The SunPy; Christe, Steven; Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y; Inglis, Andrew R; Liedtke, Simon; Hewett, Russell J; Mayer, Florian; Hughitt, Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M; Malocha, Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J; Robitaille, Thomas P; Mampaey, Benjamin; Campos-Rozo, Jose Iván; Kirk, Michael S

    2015-01-01

    This paper presents SunPy (version 0.5), a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation (NumPy, SciPy) and machine learning (scikit-learn) to visualisation and plotting (matplotlib). SunPy is a data-analysis environment specialising in providing the software necessary to analyse solar and heliospheric data in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from mis...

  1. Essential Outdoor Sun Safety Tips for Winter

    Science.gov (United States)

    ... ve Got Skin in the Game Anti-Aging Vitamin D Related: What Is Skin Cancer? | True Stories | Ask the Experts Blog Events ... Weekend Warriors expand/collapse Golf: You've Got Skin in the Game expand/collapse Vitamin D Essential Outdoor Sun Safety Tips for Winter ...

  2. Sino-Sun Architects & Engineers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Sino-Sun is an A-Class state architectural design company organized by a group of experts who have returned to China after studying abroad. In the 10 yearssince its establishment, it has grown into an outstanding andwell-known design team, which has influence in the national archi-tectural design field.

  3. Ulysses Passes South Pole of Sun

    Institute of Scientific and Technical Information of China (English)

    程林

    1995-01-01

    On the 14th of September,1994, the fastest scientific instrument in space passed the south pole of the Sun,a place where no human-made object has been before. A spaceprobe called Ulysses made the polar pass at about midday as it continued to collect data on the solar wind,a stream of high-energy sub-atomic

  4. Isotopes Tell Sun's Origin and Operation

    Science.gov (United States)

    Manuel, O.; Kamat, Sumeet A.; Mozina, Michael

    2006-03-01

    Modern versions of Aston's mass spectrometer enable measurements of two quantities - isotope abundances and masses - that tell the Sun's origin and operation. Isotope analyses of meteorites, the Earth, Moon, Mars, Jupiter, the solar wind, and solar flares over the past 45 years indicate that fresh, poorly-mixed, supernova debris formed the solar system. The iron-rich Sun formed on the collapsed supernova core and now itself acts as a magnetic plasma diffuser, as did the precursor star, separating ions by mass. This process covers the solar surface with lightweight elements and with the lighter isotopes of each element. Running difference imaging provides supporting evidence of a rigid, iron-rich structure below the Sun's fluid outer layer of lightweight elements. Mass measurements of all 2,850 known nuclides expose repulsive interactions between neutrons that trigger neutron-emission at the solar core, followed by neutron-decay and a series of reactions that collectively generate solar luminosity, solar neutrinos, the carrier gas for solar mass separation, and an outpouring of solar-wind hydrogen from the solar surface. Neutron-emission and neutron-decay generate ~ 65% of solar luminosity; H-fusion ~ 35%, and ~ 1% of the neutron-decay product survives to depart as solar-wind hydrogen. The energy source for the Sun and other ordinary stars seems to be neutron-emission and neutron-decay, with partial fusion of the decay product, rather than simple fusion of hydrogen into helium or heavier elements.

  5. Sun Baiqiu Fights for the Human Cause

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    SUN Baiqiu liked to read well known literature from all over the world when she was a little girl. She sympathized with the good-hearted characters and hated the greedy and the evil. She imagined that she would become like a fairy godmother, holding a magic wand and helping the poor but kind people in distress. In 1963 she graduated from Haerbin

  6. Nocturnal aerosol optical thickness measured with a sun/moon photometer developed by improving the Prede Sky-radiometer

    Science.gov (United States)

    Shiobara, Masataka; Kobayashi, Hiroshi; Hishida, Kosuke; Uchiyama, Akihiro

    2017-04-01

    Sun photometry to obtain the aerosol optical thickness (AOT) needs the sun. Since the moon must be another source of light instead of the sun during night-time, a moon photometer was developed by improving the Prede POM-02 Sky-radiometer to measure the spectral lunar irradiance. The original POM-02 model has an electric dynamic range of 109 to measure both of direct- and circum-solar radiation. The electronics of POM-02 was upgraded to include a 1011 dynamic range for better performance to measure the direct lunar irradiance at the visible range as well as the sun and sky measurements with a single instrument. A CCD-based position sensor was newly developed to track the moon as well as the sun continuously. The position of the moon/sun is determined with accuracy of better than 0.01° by a real-time processing system using the CCD imager. Test measurements with the improved POM-02 instrument were performed for the half to full moon conditions, and showed a good performance for lunar photometry to obtain the nocturnal AOTs.

  7. Wearable wireless photoplethysmography sensors

    Science.gov (United States)

    Spigulis, Janis; Erts, Renars; Nikiforovs, Vladimirs; Kviesis-Kipge, Edgars

    2008-04-01

    Wearable health monitoring sensors may support early detection of abnormal conditions and prevention of their consequences. Recent designs of three wireless photoplethysmography monitoring devices embedded in hat, glove and sock, and connected to PC or mobile phone by means of the Bluetooth technology, are described. First results of distant monitoring of heart rate and pulse wave transit time using the newly developed devices are presented.

  8. Correction of sun glint effect on MIVIS data of the Sicily campaign in July 2000

    Directory of Open Access Journals (Sweden)

    E. Zappitelli

    2006-06-01

    Full Text Available To assess the suspended and dissolved matter in water in the visible and near infrared spectral regions it is necessary to estimate with adequate accuracy the water leaving radiance. Consequently radiance measured by a remote sensor has to be corrected from the atmospheric and the sea surface effects consisting in the path radiance and the sun and sky glitter radiance contributions. This paper describes the application of the sun glint correction scheme on to airborne hyperspectral MIVIS measurements acquired on the area of the Straits of Messina during the campaign in July 2000. In the Messina case study data have been corrected for the atmospheric effects and for the sun-glitter contribution evaluated following the method proposed by Cox and Munk (1954, 1956. Comparison between glitter contaminated and glitter free data has been made taking into account the radiance profiles relevant to selected scan lines and the spectra of different pixels belonging to the same scan line and located out and inside the sun glitter area. The results show that spectra after correction have the same profile as the contaminated ones, although, at this stage, free glint data have not yet been used in water constituent retrieval and consequently the reliability of such correction cannot be completely evaluated.

  9. School Sun-Protection Policies--Does Being SunSmart Make a Difference?

    Science.gov (United States)

    Turner, Denise; Harrison, Simone L.; Buettner, Petra; Nowak, Madeleine

    2014-01-01

    Evaluate the comprehensiveness of primary school sun-protection policies in tropical North Queensland, Australia. Pre-determined criteria were used to assess publicly available sun-protection policies from primary schools in Townsville (latitude 19.3°S; n = 43), Cairns (16.9°S; n = 46) and the Atherton Tablelands (17.3°S; n = 23) during 2009-2012.…

  10. Observing the Sun with NuSTAR

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a space telescope primarily designed to detect high-energy X-rays from faint, distant astrophysical sources. Recently, however, its occasionally been pointing much closer to home, with the goal of solving a few longstanding mysteries about the Sun.Intensity maps from an observation of a quiet-Sun region near the north solar pole and an active region just below the solar limb. The quiet-Sun data will be searched for small flares that could be heating the solar corona, and the high-altitude emission above the limb may provide clues about particle acceleration. [Adapted from Grefenstette et al. 2016]An Unexpected TargetThough we have a small fleet of space telescopes designed to observe the Sun, theres an important gap: until recently, there was no focusing telescope making solar observations in the hard X-ray band (above ~3 keV). Conveniently, there is a tool capable of doing this: NuSTAR.Though NuSTARs primary mission is to observe faint astrophysical X-ray sources, a team of scientists has recently conducted a series of observations in which NuSTAR was temporarily repurposed and turned to focus on the Sun instead.These observations pose an interesting challenge precisely because of NuSTARs extreme sensitivity: pointing at such a nearby, bright source can quickly swamp the detectors. But though the instrument cant be used to observe the bright flares and outbursts from the Sun, its the perfect tool for examining the parts of the Sun weve been unable to explore in hard X-rays before now such as faint flares, or the quiet, inactive solar surface.In a recently published study led by Brian Grefenstette (California Institute of Technology), the team describes the purpose and initial results of NuSTARs first observations of the Sun.Solar MysteriesWhat is NuSTAR hoping to accomplish with its solar observations? There are two main questions that hard X-ray observations may help to answer.How are particles accelerated in

  11. Matter in transition

    CERN Document Server

    Anderson, Lara B; Raghuram, Nikhil; Taylor, Washington

    2015-01-01

    We explore a novel type of transition in certain 6D and 4D quantum field theories, in which the matter content of the theory changes while the gauge group and other parts of the spectrum remain invariant. Such transitions can occur, for example, for SU(6) and SU(7) gauge groups, where matter fields in a three-index antisymmetric representation and the fundamental representation are exchanged in the transition for matter in the two-index antisymmetric representation. These matter transitions are realized by passing through superconformal theories at the transition point. We explore these transitions in dual F-theory and heterotic descriptions, where a number of novel features arise. For example, in the heterotic description the relevant 6D SU(7) theories are described by bundles on K3 surfaces where the geometry of the K3 is constrained in addition to the bundle structure. On the F-theory side, non-standard representations such as the three-index antisymmetric representation of SU(N) require Weierstrass models...

  12. A Tracking Sun Photometer Without Moving Parts

    Science.gov (United States)

    Strawa, Anthony W.

    2012-01-01

    This innovation is small, lightweight, and consumes very little electricity as it measures the solar energy attenuated by gases and aerosol particles in the atmosphere. A Sun photometer is commonly used on the Earth's surface, as well as on aircraft, to determine the solar energy attenuated by aerosol particles in the atmosphere and their distribution of sizes. This information is used to determine the spatial and temporal distribution of gases and aerosols in the atmosphere, as well as their distribution sizes. The design for this Sun photometer uses a combination of unique optics and a charge coupled device (CCD) array to eliminate moving parts and make the instrument more reliable. It could be selfcalibrating throughout the year. Data products would be down-welling flux, the direct-diffuse flux ratio, column abundance of gas phase constituents, aerosol optical depth at multiple-wavelengths, phase functions, cloud statistics, and an estimate of the representative size of atmospheric particles. These measurements can be used to obtain an estimate of aerosol size distribution, refractive index, and particle shape. Incident light is received at a light-reflecting (inner) surface, which is a truncated paraboloid. Light arriving from a hemispheric field of view (solid angle 2 steradians) enters the reflecting optic at an entrance aperture at, or adjacent to, the focus of the paraboloid, and is captured by the optic. Most of this light is reflected from an inner surface. The light proceeds substantially parallel to the paraboloid axis, and is detected by an array detector located near an exit aperture. Each of the entrance and exit apertures is formed by the intersection of the paraboloid with a plane substantially perpendicular to the paraboloid axis. Incident (non-reflected) light from a source of limited extent (the Sun) illuminates a limited area on the detector array. Both direct and diffuse illumination may be reflected, or not reflected, before being received on

  13. UV photography, masculinity, and college men's sun protection cognitions.

    Science.gov (United States)

    Walsh, Laura A; Stock, Michelle L

    2012-08-01

    This study examined the impact of an ultraviolet (UV) photography intervention and masculinity on college men's sun protection cognitions, including: perceived vulnerability to skin damage, attitudes toward sun protection, willingness to engage in sun protection behaviors, and intentions to receive a skin cancer exam. After completing a baseline survey, participants (N = 152) viewed a black-and-white photo of their face. Half also viewed a photo showing their UV damage. Participants then completed a second survey assessing sun protection cognitions. Regressions revealed that masculinity predicted lower sun protection cognitions, and men in the UV photograph condition reported higher sun protection cognitions. Masculinity by condition interactions showed that the positive effect of UV photography was stronger among masculine men. Negative associations between masculinity and sun protection cognitions were significant only among men who did not receive the intervention. Findings suggest that UV photography is a promising sun protection intervention among masculine men.

  14. Neutrinos from WIMP annihilations in the Sun including neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blennow, Mattias, E-mail: emb@kth.se [Department of Theoretical Physics, School of Engineering Sciences, Royal Institute of Technology (KTH) - AlbaNova University Center, SE-106 91 Stockholm (Sweden); Edsjoe, Joakim, E-mail: edsjo@physto.se [Department of Physics, Stockholm University - AlbaNova University Center, SE-106 91 Stockholm (Sweden); Ohlsson, Tommy, E-mail: tommy@theophys.kth.se [Department of Theoretical Physics, School of Engineering Sciences, Royal Institute of Technology (KTH) - AlbaNova University Center, SE-106 91 Stockholm (Sweden)

    2011-12-15

    The prospects to detect neutrinos from the Sun arising from dark matter annihilations in the core of the Sun are reviewed. Emphasis is placed on new work investigating the effects of neutrino oscillations on the expected neutrino fluxes.

  15. How Can I Protect My Children from the Sun?

    Science.gov (United States)

    ... How Can I Protect My Children from the Sun? Language: English Español (Spanish) Recommend on Facebook Tweet ... other options to prevent UV damage. Too Much Sun Hurts Turning pink? Unprotected skin can be damaged ...

  16. Spontaneously Symmetry-Breaking States in the Attractive SU(N) Hubbard Model

    Science.gov (United States)

    Koga, Akihisa; Yanatori, Hiromasa

    2017-03-01

    We investigate spontaneously symmetry-breaking states in the attractive SU(N) Hubbard model at half filling. Combining dynamical mean-field theory with the continuous-time quantum Monte Carlo method, we obtain finite-temperature phase diagrams for the superfluid state. When N > 2, a second-order phase transition occurs in the weak coupling region, while a first-order phase transition with hysteresis appears in the strong coupling region. We also discuss the stability of the density wave state and clarify the component dependence of the maximum critical temperature.

  17. Blinded by the light the secret life of the sun

    CERN Document Server

    Gribbin, John

    1991-01-01

    An investigation into the secrets and the new scientific developments which are changing our perceptions of the sun. The book tackles such questions as: does the sun breathe?; can it make sound?; is its centre ice-cold? The new research in sun science will alter our perception not only of the sun, but of the whole universe and add to the understanding of how the world works. The author has also written "Hothouse Earth" and "The Hole in the Sky".

  18. Observing the sun a pocket field guide

    CERN Document Server

    Jenkins, Jamey L

    2013-01-01

    A comprehensive solar observing guide for use at the telescope by amateur astronomers at all three levels: beginning, intermediate, and advanced. Users will find invaluable information for identifying features through photos, charts, diagrams in a logical, orderly fashion and then interpreting the observations. Because the Sun is a dynamic celestial body in constant flux, astronomers rarely know for certain what awaits them at the eyepiece. All features of the Sun are transient and sometimes rather fleeting. Given the number of features and the complex life cycles of some solar features, it can be a challenging hobby, and this guide provides all of the guidance necessary to inform observers about the sights and events unfolding before their eyes on the most active and powerful member of our Solar System.

  19. Power producing sun shades; Elproducerende solafskaermninger

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, K.; Soerensen, Henrik; Katic, I.; Schmidt-Petersen, H.; AAroe, D.

    2012-01-15

    Integrating photovoltaics into sun shades takes advantage of the best opportunities to capture and utilize solar energy when the shades are most needed to shield users from solar radiation. The report describes results of a development project for solar shading in the form of broad, horizontal and rotating lamellae with solar cells and an integrated control function that simultaneously is optimized based on energy consumption and thermal and visual indoor climate. The project idea was to meet the needs for effective sun protection in the present office, commercial and public buildings, where glass facades are dominant. The conclusion of the development project is that it rarely would be optimal to integrate solar cells into movable shades. This will normally only be relevant in cases where it is justified by architectural considerations. (LN)

  20. Hierarchical analysis of the quiet Sun magnetism

    CERN Document Server

    Ramos, A Asensio

    2014-01-01

    Standard statistical analysis of the magnetic properties of the quiet Sun rely on simple histograms of quantities inferred from maximum-likelihood estimations. Because of the inherent degeneracies, either intrinsic or induced by the noise, this approach is not optimal and can lead to highly biased results. We carry out a meta-analysis of the magnetism of the quiet Sun from Hinode observations using a hierarchical probabilistic method. This model allows us to infer the statistical properties of the magnetic field vector over the observed field-of-view consistently taking into account the uncertainties in each pixel due to noise and degeneracies. Our results point out that the magnetic fields are very weak, below 275 G with 95% credibility, with a slight preference for horizontal fields, although the distribution is not far from a quasi-isotropic distribution.

  1. A new perspective on quiet Sun magnetism

    Institute of Scientific and Technical Information of China (English)

    LITES; Bruce; William

    2009-01-01

    The Hinode mission has provided us with a new, quantitative view of the magnetism of the quiet Sun. It has revealed that the quiet internetwork areas are blanketed by horizontal fields that appear at first sight to have more flux than the vertical fields resolved on the same 0.3 size scale. These measurements point to the possibility that the horizontal fields might be the primary source of the "hidden turbulent flux" of the quiet Sun anticipated from Hanle effect depolarization. In this paper, evidence is presented suggesting that the "seething" horizontal fields observed by Harvey in 2007 and the horizontal fields revealed by Hinode are the same phenomenon. Because the seething fields appear to be of uniform fluctuation over the whole disk, the phenomenon is most likely not associated with the dynamo source of solar activity. Thus, the small-scale "hidden turbulent flux" lends support to the notion of a local solar dynamo acting on granular sizes and time scales.

  2. Under the Lens: Investigating the Sun's Mysteries

    Science.gov (United States)

    Harwood, William; Klotz, Irene

    2008-11-01

    Sometime around 2012, the waxing 11-year solar cycle once again will reach its peak. Between now and then, magnetically turbulent sunspots, spawned by some still mysterious process, will form near the poles in increasing numbers and migrate toward the Sun's faster-rotating equator in pairs of opposite polarity. Titanic magnetic storms will rage as immense flux tubes rise to the surface in active regions around sunspots and spread out in a boiling sea of electric charge. Magnetic field lines across an enormous range of scales will arc and undulate, rip apart and reconnect, heating the Sun's upper atmosphere and occasionally triggering brilliant flares and multibillion-megaton coronal mass ejections (CMEs) that travel through the solar wind and slam into Earth.

  3. Wreathes of Magnetism in Rapidly Rotating Suns

    CERN Document Server

    Brown, Benjamin P; Brun, Allan Sacha; Toomre, Juri

    2009-01-01

    When our Sun was young it rotated much more rapidly than now. Observations of young, rapidly rotating stars indicate that many possess substantial magnetic activity and strong axisymmetric magnetic fields. We conduct simulations of dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical harmonic (ASH) code to explore the complex coupling between rotation, convection and magnetism. Here we study dynamo action realized in the bulk of the convection zone for two systems, rotating at three and five times the current solar rate. We find that substantial organized global-scale magnetic fields are achieved by dynamo action in these systems. Striking wreathes of magnetism are built in the midst of the convection zone, coexisting with the turbulent convection. This is a great surprise, for many solar dynamo theories have suggested that a tachocline of penetration and shear at the base of the convection zone is a crucial ingredient for organized dynamo action, whereas these simulations do not includ...

  4. How plants LINC the SUN to KASH.

    Science.gov (United States)

    Zhou, Xiao; Meier, Iris

    2013-01-01

    Linkers of the nucleoskeleton to the cytoskeleton (LINC) complexes formed by SUN and KASH proteins are conserved eukaryotic protein complexes that bridge the nuclear envelope (NE) via protein-protein interactions in the NE lumen. Revealed by opisthokont studies, LINC complexes are key players in multiple cellular processes, such as nuclear and chromosomal positioning and nuclear shape determination, which in turn influence the generation of gametes and several aspects of development. Although comparable processes have long been known in plants, the first plant nuclear envelope bridging complexes were only recently identified. WPP domain-interacting proteins at the outer NE have little homology to known opisthokont KASH proteins, but form complexes with SUN proteins at the inner NE that have plant-specific properties and functions. In this review, we will address the importance of LINC complex-regulated processes, describe the plant NE bridging complexes and compare them to opisthokont LINC complexes.

  5. ADVANCED BURNING STAGES AND FATE OF 8-10 M{sub Sun} STARS

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S.; Hirschi, R. [Astrophysics Group, Lennard Jones Building, Keele University, Staffordshire ST5 5BG (United Kingdom); Nomoto, K. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Fischer, T.; Martinez-Pinedo, G. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany); Timmes, F. X. [School of Earth and Space Exploration, University of Arizona, Tempe, AZ 85287 (United States); Herwig, F. [Joint Institute for Nuclear Astrophysics, University of Notre Dame, IN 46556 (United States); Paxton, B. [KITP and Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Toki, H. [Research Center for Nuclear Physics (RCNP), Osaka University, Osaka 567-0047 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Lam, Y. H. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, D-64289 Darmstadt (Germany); Bertolli, M. G., E-mail: s.w.jones@keele.ac.uk [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-08-01

    The stellar mass range 8 {approx}< M/M{sub Sun} {approx}< 12 corresponds to the most massive asymptotic giant branch (AGB) stars and the most numerous massive stars. It is host to a variety of supernova (SN) progenitors and is therefore very important for galactic chemical evolution and stellar population studies. In this paper, we study the transition from super-AGB (SAGB) star to massive star and find that a propagating neon-oxygen-burning shell is common to both the most massive electron capture supernova (EC-SN) progenitors and the lowest mass iron-core-collapse supernova (FeCCSN) progenitors. Of the models that ignite neon-burning off-center, the 9.5 M{sub Sun} star would evolve to an FeCCSN after the neon-burning shell propagates to the center, as in previous studies. The neon-burning shell in the 8.8 M{sub Sun} model, however, fails to reach the center as the URCA process and an extended (0.6 M{sub Sun }) region of low Y{sub e} (0.48) in the outer part of the core begin to dominate the late evolution; the model evolves to an EC-SN. This is the first study to follow the most massive EC-SN progenitors to collapse, representing an evolutionary path to EC-SN in addition to that from SAGB stars undergoing thermal pulses (TPs). We also present models of an 8.75 M{sub Sun} SAGB star through its entire TP phase until electron captures on {sup 20}Ne begin at its center and of a 12 M{sub Sun} star up to the iron core collapse. We discuss key uncertainties and how the different pathways to collapse affect the pre-SN structure. Finally, we compare our results to the observed neutron star mass distribution.

  6. Sensor Compendium

    CERN Document Server

    Artuso, M; Bolla, G; Bortoletto, D; Caberera, B; Carlstrom, J E; Chang, C L; Cooper, W; Da Via, C; Demarteau, M; Fast, J; Frisch, H; Garcia-Sciveres, M; Golwala, S; Haber, C; Hall, J; Hoppe, E; Irwin, K D; Kagan, H; Kenney, C; Lee, A T; Lynn, D; Orrell, J; Pyle, M; Rusack, R; Sadrozinski, H; Sanchez, M C; Seiden, A; Trischuk, W; Vavra, J; Wetstein, M; Zhu, R-Y

    2013-01-01

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future ...

  7. International Sun-Earth Explorer (ISEE)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Series of three US satellites designed to study the solar wind and its interaction with the Earth's magnetosphere. ISEE-1 and 2 were placed into highly elliptical Earth orbits. ISEE-3 was placed in a halo orbit at the L1 Lagrangian point between the Sun and Earth. It gave advance warning of solar storms heading towards Earth. (See also INTERNATIONAL COMETARY EXPLORER and EXPLORER.)...

  8. Operational Art and the Rising Sun

    Science.gov (United States)

    1994-05-16

    shall run wild for the first six months or a year, but I have utterly no confidence for the second or third ’Potter, p. 46; Michael Slackman, Target...attack that no american carriers in 26Joseph K. Taussig , "A Tactical View of Pearl Harbor", Paul Stillwell, ed., Air Raid: Pearl Harbor! (Annapolis, MD...Weiner, 1991. Slackman, Michael . Target: Pearl Harbor. Honolulu: University of Hawaii Press, 1990. Stephan, John J. Hawaii Under the Rising Sun

  9. Complete Solution of Sun Tracking for Heliostat

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-Tian; LIM Boon-Han; LIM Chern-Sing

    2006-01-01

    A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuthelevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general solution and its significance in solar energy engineering are discussed.

  10. Complete Solution of Sun Tracking for Heliostat

    Science.gov (United States)

    Chen, Ying-Tian; Lim, Boon-Han; Lim, Chern-Sing

    2006-01-01

    A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuth-elevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general solution and its significance in solar energy engineering are discussed.

  11. Wind Sensor

    OpenAIRE

    Li, Jiaoyang; Ni, Jiqin

    2014-01-01

    Wind measurement is needed in many practical and scientific research situations. Some specific applications require to precisely measuring both wind direction and wind speed at the same time. Current commercial sensors for wind direction and wind speed measurement usually use ultrasonic technology and the sensors are very expensive (> $1500). In addition, the sensors are large in dimension and cannot measure airflow patterns in high spatial resolution. Therefore new and low cost wind speed an...

  12. Outdoor Workers' Use of Sun Protection at Work and Leisure

    Directory of Open Access Journals (Sweden)

    Cheryl E. Peters

    2016-09-01

    Conclusion: This high-participation rate cohort helps characterize sun protection behaviors among outdoor workers. Workers practiced better sun protection at work than on weekends, suggesting that workplace policies supportive of sun protection could be useful for skin cancer prevention in the construction industry.

  13. ON FELICITOUS CHARACTER OF GENERALIZED SUN-GRAPHS

    Institute of Scientific and Technical Information of China (English)

    YANG Si-hua; YAO Bing; YAO Ming

    2015-01-01

    Felicitous character of some generalized sun-graphs is investigated in this note, and furthermore the exact felicitous labellings of two classes of generalized sun-graphs are obtained by analyzing the structures of the generalized sun-graphs. And the constructed graph theory models in coding theory, communication networks, logistics and other aspects have important applications.

  14. Exploring Young People's Beliefs and Images about Sun Safety

    Science.gov (United States)

    White, K. M.; Robinson, N. G.; Young, R. McD.; Anderson, P. J.; Hyde, M. K.; Greenbank, S.; Keane, J.; Rolfe, T.; Vardon, P.; Baskerville, D.

    2008-01-01

    To understand young people's low levels of sun protection behaviour, 145 young people (aged 12 to 20 years) were recruited from Queensland, to participate in a one-hour focus group where they discussed issues related to sun protection and images of tanned and non-tanned people. Responses were content analysed to identify common sun protection…

  15. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  16. Sensor web

    Science.gov (United States)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  17. New Views of the Sun: STEREO and Hinode

    Science.gov (United States)

    Luhmann, Janet G.; Tsuneta, Saku; Bougeret, J.-L.; Galvin, Antoinette; Howard, R. A.; Kaiser, Michael; Thompson, W. T.

    The twin-spacecraft STEREO mission has now been in orbit for 1.5 years. Although the main scientific objective of STEREO is the origin and evolution of Coronal Mass Ejections (CMEs) and their heliospheric consequences, the slow decline of the previous solar cycle has provided an extraordinary opportunity for close scrutiny of the quiet corona and solar wind, including suprathermal and energetic particles. However, STEREO has also captured a few late cycle CMEs that have given us a taste of the observations and analyses to come. Images from the SECCHI investigation afforded by STEREO's separated perspectives and the heliospheric imager have already allowed us to visibly witness the origins of the slow solar wind and the Sun-to-1 AU transit of ICMEs. The SWAVES investigation has monitored the transit of interplanetary shocks in 3D while the PLASTIC and IMPACT in-situ measurements provide the 'ground truth' of what is remotely sensed. New prospects for space weather forecasting have been demonstrated with the STEREO behind spacecraft, a successful proof-of-concept test for future space weather mission designs. The data sets for the STEREO investigations are openly available through a STEREO Science Center web interface that also provides supporting information for potential users from all communities. Comet observers and astronomers, interplanetary dust researchers and planetary scientists have already made use of this resource. The potential for detailed Sun-to-Earth CME/ICME interpretations with sophisticated modeling efforts are an upcoming STEREO-Hinode partnering activity whose success we can only anticipate at this time. Since its launch in September 2006, Hinode has sent back solar images of unprecedented clarity every day. The primary purpose of this mission is a systems approach to understanding the generation, transport and ultimate dissipation of solar magnetic fields with a well-coordinated set of advanced telescopes. Hinode is equipped with three

  18. CRYOGENIC SYSTEM FOR PRECISE CALIBRATION OF TEMPERATURE SENSORS

    Directory of Open Access Journals (Sweden)

    A. N. Solovyev

    2016-09-01

    Full Text Available A calibration technique for cryogenic temperature sensors is proposed and implemented. The experimental setup is based on the helium cryogenerator, providing calibration of the temperature sensors of various types in wide temperature range, including cryogenic band (25-100K. A condensation thermometer with hydrogen, neon, argon and xenon as working gases is used as a reference sensor. The experimental setup was successfully used for precise (0.1K precision calibration of platinum resistive temperature detectors (Pt-100 for international nuclear physics experiments MuSun and PolFusion. The setup can also be used for calibration of temperature sensors of the other types.

  19. Keeping Cool Close to the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Hazi, A

    2006-01-13

    The germanium detector in the gamma-ray spectrometer (GRS) aboard the MESSENGER spacecraft is only the size and weight of a can of peaches but will play a critical role in investigating Mercury, the planet closest to the Sun. The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft travels at about 38 kilometers per second and is named after the scientific goals of the mission. It is the first spacecraft to visit Mercury since 1975. MESSENGER must take an oblique route to approach Mercury so that it does not fly past the planet and fall directly into the Sun. The spacecraft will travel 7.9 billion kilometers, flying by Earth once, Venus twice, and Mercury three times before settling into orbit around this mysterious planet. Of all the terrestrial planets, which include Venus, Earth, and Mars, Mercury is the smallest and the densest; its days are 176 Earth days long, two complete orbits of the planet around the Sun. Temperatures range from a high of 450 C on the Sun side during its long day to a low of -185 C on its night side. By studying this extreme planet, scientists hope to better understand how Earth formed and evolved. The GRS, one of the seven lightweight scientific instruments on MESSENGER, will be used to help scientists determine the abundance of elements in Mercury's crust, including the materials that might be ice at its poles. Livermore engineer Norman Madden led the West Coast team effort to design and build the GRS in a collaboration led by Johns Hopkins University Applied Physics Laboratory (JHUAPL). The team included Lawrence Berkeley and Lawrence Livermore national laboratories as well as University of California at Berkeley (UCB) Space Sciences Laboratory (SSL). The JHUAPL MESSENGER project is a National Aeronautics and Space Administration (NASA) Discovery Mission. Because the detector needs to operate at very low temperatures and MESSENGER is close to the Sun, the thermal design to protect the detector was

  20. The Telemachus mission: dynamics of the polar sun and heliosphere

    Science.gov (United States)

    Roelof, E.

    Telemachus in Greek mythology was the faithful son of Ulysses. The Telemachus mission is envisioned as the next logical step in the exploration of the polar regions of the Sun and heliosphere so excitingly initiated by the ESA/NASA Ulysses mission. Telemachus is a polar solar-heliospheric mission described in the current NASA Sun-Earth Connections Roadmap (2003-2028) that has successfully undergone two Team X studies by NASA/JPL. The pioneering observations from Ulysses transformed our perception of the structure and dynamics of these polar regions through which flow the solar wind, magnetic fields and energetic particles that eventually populate most of the volume of the heliosphere. Ulysses carried only fields and particles detectors. Telemachus, in addition to modern versions of such essential in situ instruments, will carry imagers that will give solar astronomers a new viewpoint on coronal mass ejections and solar flares, as well as their first purely polar views of the photospheric magnetic field, thereby providing new helioseismology to probe the interior of the Sun. Unlike the RTG-powered Ulysses, the power for Telemachus will come simply from solar panels. Gravity assist encounters with Venus and Earth (twice) will yield ˜5 years of continuous in-ecliptic cruise science between 0.7 AU and 3.3 AU that will powerfully complement other contemporary solar-heliospheric missions. The Jupiter gravity assist, followed by a perihelion burn ˜8 years after launch, will place Telemachus in a permanent ˜0.2 AU by 2.5 AU heliographic polar orbit (inclination >80 deg) whose period will be 1.5 years. Telemachus will then pass over the solar poles at ˜0.4 AU (compared to 1.4 AU for Ulysses) and spend ˜2 weeks above 60 deg on each polar pass (alternating perihelions between east and west limbs as viewed from Earth). In 14 polar passes during a 10.5 year solar cycle, Telemachus would accumulate over half a year of polar science data. During the remainder of the time, it

  1. Watching the Sun to Improve Exoplanet Detection

    Science.gov (United States)

    Kohler, Susanna

    2015-12-01

    Looking for stars that wobble is one of the key ways by which we detect exoplanets: the gravitational pull of planets cause tiny variations in stars radial velocities. But our ability to detect Earth twins is currently limited by our ability to distinguish between radial-velocity variations caused by exoplanets, and those caused by noise from the star itself. A team of scientists has recently proposed that the key to solving this problem may be to examine our own star.Precision Amid NoiseThe radial-velocity technique works well for detecting large planets on close orbits, but detecting an Earth twin requires being able to detect star motion on the order of 10 cm/s! This precision is hard to reach, because activity on the stellar surface i.e., sunspots, plages (bright spots), or granulation can also cause variations in the measured radial velocity for the star, obscuring the signature of a planet.Because the stars were examining arent resolved, we cant track the activity on their surfaces so how can we better understand the imprint that stellar activity has on radial-velocity measurements? A team of scientists has come up with a clever approach: examine the Sun as though it were a distant star.Wealth of InformationThe team, led by Xavier Dumusque (Branco-Weiss Fellow at the Harvard-Smithsonian Center for Astrophysics) and David F. Phillips (Harvard-Smithsonian Center for Astrophysics), has begun a project to observe the Sun with a ground-based solar telescope. The telescope observes the full disk of the Sun and feeds the data into the HARPS-N spectrograph in Spain, a spectrograph normally used for radial-velocity measurements of other stars in the hunt for exoplanets.But the team has access to other data about the Sun, too: information from satellites like the Solar Dynamics Observatory and SORCE about the solar activity and total irradiance during the time when the spectra were taken. Dumusque and collaborators have combined all of this information, during a week

  2. Monitoring Holes in the Sun's Corona

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Coronal holes are where the fast solar wind streams out of the Suns atmosphere, sending charged particles on rapid trajectories out into the solar system. A new study examines how the distribution of coronal holes has changed over the last 40 years.Coronal holes form where magnetic field lines open into space (B) instead of looping back to the solar surface (A). [Sebman81]Source of the Fast Solar WindAs a part of the Suns natural activity cycle, extremely low-density regions sometimes form in the solar corona. These coronal holes manifest themselves as dark patches in X-ray and extreme ultraviolet imaging, since the corona is much hotter than the solar surface that peeks through from underneath it.Coronal holes form when magnetic field lines open into space instead of looping back to the solar surface. In these regions, the solar atmosphere escapes via these field lines, rapidly streaming away from the Suns surface in whats known as the fast solar wind.Coronal Holes Over Space and TimeAutomated detection of coronal holes from image-based analysis is notoriously difficult. Recently, a team of scientists led by Kenichi Fujiki (ISEE, Nagoya University, Japan) has developed an automated prediction technique for coronal holes that relies instead on magnetic-field data for the Sun, obtained at the National Solar Observatorys Kitt Peak between 1975 and 2014. The team used these data to produce a database of 3335 coronal hole predictions over nearly 40 years.Latitude distribution of 2870 coronal holes (each marked by an x; color indicates polarity), overlaid on the magnetic butterfly map of the Sun. The low-latitude coronal holes display a similar butterfly pattern, in which they move closer to the equator over the course of the solar cycle. Polar coronal holes are more frequent during solar minima. [Fujiki et al. 2016]Examining trends in the coronal holes distribution in latitude and time, Fujiki and collaborators find a strong correlation between the total area covered

  3. Sun protecting and sun exposing behaviors: testing their relationship simultaneously with indicators of ultraviolet exposure among adolescents.

    Science.gov (United States)

    Williams, Melinda; Caputi, Peter; Jones, Sandra C; Iverson, Don

    2011-01-01

    The aim of this study was to build on existing understanding of adolescent sun-related behavior by combining sun protecting and sun exposing behaviors and testing their relationship simultaneously with indicators of ultraviolet (UV) exposure. Data were collected for 692 adolescents aged between 12 and 18 years. General linear modeling was undertaken to test the relationship of sun-related behaviors with indicators of UV exposure. Overall, the combined sun protection and sun exposing behaviors accounted for 13.8% of the variance in the number of sunburns, 28.1% of the variance in current tan and 57.5% of the variance in desired tan, respectively. Results indicated that having a strong desire for a tan was significantly associated with spending time tanning, delaying the use of sun protection, wearing brief clothing and using no sun protection; whereas the number of sunburns was significantly associated with sunscreen use, avoiding peak hours and delaying sun protection. Current tan was significantly associated with wearing sunglasses, shade use and time spent tanning. In examining sun-related behaviors among adolescents, consideration needs to be given to both sun exposing and sun protecting behaviors. This research has important implications for conceptualizing outcomes in programs designed to reduce UV exposure.

  4. Sun-care product advertising in parenting magazines: what information does it provide about sun protection?

    Science.gov (United States)

    Kang, Hannah; Walsh-Childers, Kim

    2014-01-01

    This study analyzed the content of sun-care product advertisements in five major U.S. parenting magazines with high circulation: Family Circle, Parents, Family Fun, Parenting (Early Years), and Parenting (School Years). The study examined what information sun-care product advertisements tell parents about skin cancer prevention and about sunscreen use for themselves or for their children based on the Health Belief Model concepts of perceived benefits and perceived barriers. Results showed that the most commonly mentioned benefit of the product was that it blocks ultraviolet A (UVA) and ultraviolet B (UVB) rays. One-third of the ads promoted the product's effectiveness in overcoming four of the barriers that prevent people from using sunscreens: eye irritation, skin irritation, an unpleasant smell, and the need to reapply sunscreen too often or after physical activity. However, only a few of the ads provided information about the consequences of unprotected sun exposure or mentioned methods of sun protection or skin cancer prevention other than sunscreen use. We discuss the implications of these messages for parents' ability to understand correctly how to protect their children from damaging sun exposure.

  5. [Research on absolute calibration of sun channel of sun photometer using laser raster scanning method].

    Science.gov (United States)

    Xu, Wen-Bin; Li, Jian-Jun; Zheng, Xiao-Bing

    2013-01-01

    In the present paper, a new calibration method of absolute spectral irradiance responsivity of sun channel of sun photometer was developed. A tunable laser was used as source and a standard tranfer detector, calibrated against cryogenic absolute radiometer, was used to measure laser beam power. By raster scanning of a single collimated laser beam to generate the uniform irradiance field at the plane of effective aperture stop of sun photometer, the absolute irradiance responsivity of center wavelength of the 870 nm unpolarized sun channels of sun photometer was obtained accurately. The relative spectral irradiance responsivity of corresponding channel was obtained by using lamp-monochromator system and then used to acquire the absolute spectral irradiance responsivity in the laboratory. On the basis of the above results, the top-of-the-atmosphere responsive constant V0 was obtained by integration with extraterrestrial solar spectral irradiance data. Comparing the calibration result with that from GSFC, NASA in 2009, the difference is only 3.75%. In the last, the uncertainties of calibration were evaluated and reached to 2.06%. The principle feasibility of the new method was validated.

  6. A generic sun-tracking algorithm for on-axis solar collector in mobile platforms

    Science.gov (United States)

    Lai, An-Chow; Chong, Kok-Keong; Lim, Boon-Han; Ho, Ming-Cheng; Yap, See-Hao; Heng, Chun-Kit; Lee, Jer-Vui; King, Yeong-Jin

    2015-04-01

    This paper proposes a novel dynamic sun-tracking algorithm which allows accurate tracking of the sun for both non-concentrated and concentrated photovoltaic systems located on mobile platforms to maximize solar energy extraction. The proposed algorithm takes not only the date, time, and geographical information, but also the dynamic changes of coordinates of the mobile platforms into account to calculate the sun position angle relative to ideal azimuth-elevation axes in real time using general sun-tracking formulas derived by Chong and Wong. The algorithm acquires data from open-loop sensors, i.e. global position system (GPS) and digital compass, which are readily available in many off-the-shelf portable gadgets, such as smart phone, to instantly capture the dynamic changes of coordinates of mobile platforms. Our experiments found that a highly accurate GPS is not necessary as the coordinate changes of practical mobile platforms are not fast enough to produce significant differences in the calculation of the incident angle. On the contrary, it is critical to accurately identify the quadrant and angle where the mobile platforms are moving toward in real time, which can be resolved by using digital compass. In our implementation, a noise filtering mechanism is found necessary to remove unexpected spikes in the readings of the digital compass to ensure stability in motor actuations and effectiveness in continuous tracking. Filtering mechanisms being studied include simple moving average and linear regression; the results showed that a compound function of simple moving average and linear regression produces a better outcome. Meanwhile, we found that a sampling interval is useful to avoid excessive motor actuations and power consumption while not sacrificing the accuracy of sun-tracking.

  7. Effects of motives on reactions to safe sun messages.

    Science.gov (United States)

    Aspden, Trefor; Ingledew, David K; Parkinson, John A

    2015-01-01

    We investigated whether appearance motive for sun exposure, which strongly predicts exposure behaviour, would predict reactions to safe sun messages. In a survey with an embedded experiment, 245 individuals completed measures of motives, read a safe sun message framed by incentive (appearance/health), tone (directive/nondirective) and valence (gain/loss), then completed measures of reactions. For participants high in appearance motive, an appearance-nondirective message was most persuasive. Regardless of individual's appearance motive, appearance messages produced lower reactance if phrased using nondirective language. To maximise persuasion and minimise reactance in individuals most motivated to sun expose, safe sun messages should focus on appearance using nondirective language.

  8. The Sun's interior structure and dynamics, and the solar cycle

    CERN Document Server

    Broomhall, A -M; Howe, R; Norton, A A; Thompson, M J

    2014-01-01

    The Sun's internal structure and dynamics can be studied with helioseismology, which uses the Sun's natural acoustic oscillations to build up a profile of the solar interior. We discuss how solar acoustic oscillations are affected by the Sun's magnetic field. Careful observations of these effects can be inverted to determine the variations in the structure and dynamics of the Sun's interior as the solar cycle progresses. Observed variations in the structure and dynamics can then be used to inform models of the solar dynamo, which are crucial to our understanding of how the Sun's magnetic field is generated and maintained.

  9. Chemical sensors

    Science.gov (United States)

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  10. Characterization monitoring & sensor technology crosscutting program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The purpose of the Characterization, Monitoring, and Sensor Technology Crosscutting Program (CMST-CP) is to deliver appropriate characterization, monitoring, and sensor technology (CMST) to the OFfice of Waste Management (EM-30), the Office of Environmental Restoration (EM-40), and the Office of Facility Transition and Management (EM-60).

  11. The Apsidal Precession for Low Earth Sun Synchronized Orbits

    Directory of Open Access Journals (Sweden)

    Shkelzen Cakaj

    2015-09-01

    Full Text Available By nodal regression and apsidal precession, the Earth flattering at satellite low Earth orbits (LEO is manifested. Nodal regression refers to the shift of the orbit’s line of nodes over time as Earth revolves around the Sun. Nodal regression is orbit feature utilized for circular orbits to be Sun synchronized. A sun¬-synchronized orbit lies in a plane that maintains a fixed angle with respect to the Earth-Sun direction. In the low Earth Sun synchronized circular orbits are suited the satellites that accomplish their photo imagery missions. Nodal regression depends on orbital altitude and orbital inclination angle. For the respective orbital altitudes the inclination window for the Sun synchronization to be attained is determined. The apsidal precession represents major axis shift, respectively the argument of perigee deviation. The apsidal precession simulation, for inclination window of sun synchronized orbital altitudes, is provided through this paper.

  12. Sun exposure and protection behavior of Danish farm children

    DEFF Research Database (Denmark)

    Bodekær, Mette; Øager Petersen, Bibi; Philipsen, Peter Alshede

    2014-01-01

    Healthy sun habits acquired in childhood could reduce skin cancer incidence. We examined the sun exposure and protection behavior of an expected high-exposure group of children, and the association to their parents. Open, prospective cohort study. One hundred and thirty nine participants (40...... families) kept daily sun behavior diaries (sun exposure, sunscreen use, sunburns) over a 4-month summer period (15,985 diary days). The Pigment Protection Factor (PPF), an objective measure of sun exposure, was measured at two body sites, before and after summer. All participants presented data from...... the same 115 days. Risk behavior (sun exposure of upper body) took place on 9.5 days (boys) and 15.6 days (girls). Sunburn and sunscreen use were infrequent. Boys' sun exposure resulted in an increased photo protection over the study period of 1.7 SED (upper arm) and 0.8 SED (shoulder) to elicit erythema...

  13. Pathogen Sensors

    Directory of Open Access Journals (Sweden)

    Joseph Irudayaraj

    2009-10-01

    Full Text Available The development of sensors for detecting foodborne pathogens has been motivated by the need to produce safe foods and to provide better healthcare. However, in the more recent times, these needs have been expanded to encompass issues relating to biosecurity, detection of plant and soil pathogens, microbial communities, and the environment. The range of technologies that currently flood the sensor market encompass PCR and microarray-based methods, an assortment of optical sensors (including bioluminescence and fluorescence, in addition to biosensor-based approaches that include piezoelectric, potentiometric, amperometric, and conductometric sensors to name a few. More recently, nanosensors have come into limelight, as a more sensitive and portable alternative, with some commercial success. However, key issues affecting the sensor community is the lack of standardization of the testing protocols and portability, among other desirable elements, which include timeliness, cost-effectiveness, user-friendliness, sensitivity and specificity. [...

  14. Smart Sensors

    Science.gov (United States)

    Corsi, C.

    2007-01-01

    The term "Smart Sensors" refers to sensors which contain both sensing and signal processing capabilities with objectives ranging from simple viewing to sophisticated remote sensing, surveillance, search/track, weapon guidance, robotics, perceptronics and intelligence applications. Recently this approach is achieving higher goals by a new and revolutionary sensors concept which introduced inside the sensor some of the basic functions of living eyes, such as dynamic stare, non-uniformity compensation, spatial and temporal filtering. New objectives and requirements are presented for this type of new infrared smart sensor systems. This paper is concerned with the front end of FPA microbolometers processing, namely, the enhancement of target-to-noise ratio by background clutter suppression and the improvement in target detection by "smart" and pattern correlation thresholding.

  15. Grand Challenges in the Physics of the Sun and Sun-like Stars

    CERN Document Server

    Thompson, Michael J

    2014-01-01

    The study of stellar structure and evolution is one of the main building blocks of astrophysics, and the Sun has an importance both as the star that is most amenable to detailed study and as the star that has by far the biggest impact on the Earth and near-Earth environment through its radiative and particulate outputs. Over the past decades, studies of stars and of the Sun have become somewhat separate. But in recent years, the rapid advances in asteroseismology, as well as the quest to better understand solar and stellar dynamos, have emphasized once again the synergy between studies of the stars and the Sun. In this article I have selected two "grand challenges" both for their crucial importance and because I thnk that these two problems are tractable to significant progress in the next decade. They are (i) understanding how solar and stellar dynamos generate magnetic field, and (ii) improving the predictability of geo-effective space weather.

  16. Carousel Trackers with 1-Sun or 3-Sun Modules for Commercial Building Rooftops

    Energy Technology Data Exchange (ETDEWEB)

    Gehl, Anthony C [ORNL; Maxey, L Curt [ORNL; Fraas, Dr. Lewis [JX Crystals, Inc.; Avery, James E. [JX Crystals, Inc.; Minkin, Leonid M [ORNL; Huang, H, [JX Crystals, Inc.

    2008-01-01

    The goal is lower cost solar electricity. Herein, two evolutional steps are described toward achieving this goal. The first step is to follow the sun with a solar tracker. Herein, a carousel tracker is described for mounting on commercial building flat rooftops in order to produce more kWh per kW relative to fixed PV modules. The second evolutionary improvement is to produce lower cost 3-sun CPV modules where two thirds of the expensive single crystal silicon material is replaced by less expensive mirror material. This paper describes the performance and durability of two prototype installations demonstrating these evolutionary innovations. In the first case, the installation and operation of 2 carousels equipped with traditional flat plate modules is described. In the second case, the operation of a carousel equipped with new 3-sun CPV modules is described. Both systems have been operating as expected for several months through the winter of 2007.

  17. Performance of 3-Sun Mirror Modules on Sun Tracking Carousels on Flat Roof Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Fraas, Dr. Lewis [JX Crystals, Inc.; Avery, James E. [JX Crystals, Inc.; Minkin, Leonid M [ORNL; Maxey, L Curt [ORNL; Gehl, Anthony C [ORNL; Hurt, Rick A [ORNL; Boehm, Robert F [ORNL

    2008-01-01

    Commercial buildings represent a near term market for cost competitive solar electric power provided installation costs and solar photovoltaic module costs can be reduced. JX Crystals has developed a carousel sun tracker that is prefabricated and can easily be deployed on building flat roof tops without roof penetration. JX Crystals is also developing 3-sun PV mirror modules where less expensive mirrors are substituted for two-thirds of the expensive single crystal silicon solar cell surface area. Carousels each with four 3-sun modules have been set up at two sites, specifically at Oak Ridge National Lab and at the University of Nevada in Las Vegas. The test results for these systems are presented.

  18. Performance of 3-sun mirror modules on sun tracking carousels on flat roof buildings

    Science.gov (United States)

    Fraas, Lewis; Avery, James; Minkin, Leonid; Maxey, Curt; Gehl, Tony; Hurt, Rick; Boehm, Robert

    2008-08-01

    Commercial buildings represent a near term market for cost competitive solar electric power provided installation costs and solar photovoltaic module costs can be reduced. JX Crystals has developed a carousel sun tracker that is prefabricated and can easily be deployed on building flat roof tops without roof penetration. JX Crystals is also developing 3-sun PV mirror modules where less expensive mirrors are substituted for two-thirds of the expensive single crystal silicon solar cell surface area. Carousels each with four 3-sun modules have been set up at two sites, specifically at Oak Ridge National Lab and at the University of Nevada in Las Vegas. The test results for these systems are presented.

  19. Design of a Solar Tracking System Using the Brightest Region in the Sky Image Sensor.

    Science.gov (United States)

    Wei, Ching-Chuan; Song, Yu-Chang; Chang, Chia-Chi; Lin, Chuan-Bi

    2016-11-25

    Solar energy is certainly an energy source worth exploring and utilizing because of the environmental protection it offers. However, the conversion efficiency of solar energy is still low. If the photovoltaic panel perpendicularly tracks the sun, the solar energy conversion efficiency will be improved. In this article, we propose an innovative method to track the sun using an image sensor. In our method, it is logical to assume the points of the brightest region in the sky image representing the location of the sun. Then, the center of the brightest region is assumed to be the solar-center, and is mathematically calculated using an embedded processor (Raspberry Pi). Finally, the location information on the sun center is sent to the embedded processor to control two servo motors that are capable of moving both horizontally and vertically to track the sun. In comparison with the existing sun tracking methods using image sensors, such as the Hough transform method, our method based on the brightest region in the sky image remains accurate under conditions such as a sunny day and building shelter. The practical sun tracking system using our method was implemented and tested. The results reveal that the system successfully captured the real sun center in most weather conditions, and the servo motor system was able to direct the photovoltaic panel perpendicularly to the sun center. In addition, our system can be easily and practically integrated, and can operate in real-time.

  20. Design of a Solar Tracking System Using the Brightest Region in the Sky Image Sensor

    Directory of Open Access Journals (Sweden)

    Ching-Chuan Wei

    2016-11-01

    Full Text Available Solar energy is certainly an energy source worth exploring and utilizing because of the environmental protection it offers. However, the conversion efficiency of solar energy is still low. If the photovoltaic panel perpendicularly tracks the sun, the solar energy conversion efficiency will be improved. In this article, we propose an innovative method to track the sun using an image sensor. In our method, it is logical to assume the points of the brightest region in the sky image representing the location of the sun. Then, the center of the brightest region is assumed to be the solar-center, and is mathematically calculated using an embedded processor (Raspberry Pi. Finally, the location information on the sun center is sent to the embedded processor to control two servo motors that are capable of moving both horizontally and vertically to track the sun. In comparison with the existing sun tracking methods using image sensors, such as the Hough transform method, our method based on the brightest region in the sky image remains accurate under conditions such as a sunny day and building shelter. The practical sun tracking system using our method was implemented and tested. The results reveal that the system successfully captured the real sun center in most weather conditions, and the servo motor system was able to direct the photovoltaic panel perpendicularly to the sun center. In addition, our system can be easily and practically integrated, and can operate in real-time.

  1. Recursively arbitrarily vertex-decomposable suns

    Directory of Open Access Journals (Sweden)

    Olivier Baudon

    2011-01-01

    Full Text Available A graph \\(G = (V,E\\ is arbitrarily vertex decomposable if for any sequence \\(\\tau\\ of positive integers adding up to \\(|V|\\, there is a sequence of vertex-disjoint subsets of \\(V\\ whose orders are given by \\(\\tau\\, and which induce connected graphs. The aim of this paper is to study the recursive version of this problem on a special class of graphs called suns. This paper is a complement of [O. Baudon, F. Gilbert, M. Woźniak, Recursively arbitrarily vertex-decomposable graphs, research report, 2010].

  2. The radiation belt of the Sun

    CERN Document Server

    Gruzinov, Andrei

    2013-01-01

    For a given solar magnetic field, the near-Sun (phase-space) density of cosmic ray electrons and positrons of energy above about 10GeV can be calculated from first principles, without any assumptions about the cosmic ray diffusion. This is because the sunlight Compton drag must be more important than diffusion. If the solar magnetic field has an appreciable dipole component, the electron/positron density should have a belt-like dent, perhaps extending to several solar radii. The belt structure appears because the quasi-bound orbits are depopulated by the sunlight Compton drag.

  3. Search for Neutrinos from the Sun

    Science.gov (United States)

    Davis, Raymond Jr.

    1968-09-01

    A solar neutrino detection system has been built to observe the neutrino radiation from the sun. The detector uses 3,900,000 liters of tetrachloroethylene as the neutrino capturing medium. Argon is removed from the liquid by sweeping with helium gas, and counted in a small low level proportional counter. The recovery efficiency of the system was tested with Ar{sup 36} by the isotope dilution method, and also with Ar{sup 37} produced in the liquid by fast neutrons. These tests demonstrate that Ar{sup 37} produced in the liquid by neutrino capture can be removed with a 95 percent efficiency by the procedure used.

  4. Hinode, the Sun, and public outreach

    Science.gov (United States)

    Yaji, K.; Tonooka, H.; Shimojo, M.; Tokimasa, N.; Suzuki, D.; Nakamichi, A.; Shimoikura, I.

    2015-03-01

    Extended Abstract Hinode is a solar observation satellite in Japan and its launch was in September 2006. Its name means ``SUNRISE`` in Japanese. It has three instruments onboard in visible light, X-ray, EUV to solve mystery of coronal heating and origins of magnetic fields. Hinode has been providing us with impressive solar data, which are very important for not only investigating solar phenomena but also giving new knowledge about the sun to the public. In order to efficiently communicate Hinode data to the public, we organized working group for public use of Hinode data. which are composed of both researchers and educators in collaboration. As follow, we introduce our activities in brief. For the public use of Hinode data, at first, we produced two DVDs introducing Hinode observation results. In particular, second DVD contains a movie for kids, which are devloped to picturebook. Now, it is under producing an illustrated book and a planetarium program. It turn out that the DVDs help the public understand the sun from questionnaire surveys. Second, we developed teaching materials from Hinode data and had a science classroom about the sun, solar observations, practice with PC such as imaging software at junior high school. As the results, they had much interests in Hinode data. Third, we have joint observations with high school students and so on in a few years. The students compare their own data with Hinode data and have a presentation at science contests. The joint observations make their motivation higher in their activities. It is important to record and report our activities in some ways. So, we positively publish papers and have presentions in domestic/international meetings. Though we are supported in budget, resources and so on by NAOJ Hinode Team, we apply research funds for promoting our EPO activities and acquire some funds such as NAOJ Joint Research Expenses and Grands-Aid for Scientific Research Funds since the launch. This way, since its launch, we

  5. Selective factors in sun-weather research

    Science.gov (United States)

    Taylor, H. A., Jr.

    1986-01-01

    Research on the correlations between solar wind/IMF disturbances and subsequent winter troposphere vorticity changes (denoted SV) are reviewed to investigate sun-weather relationships. Uncertainties in the research attempting to link short-term solar variations and associated changes in the lower atmosphere are discussed, and it is noted that such analyses have generally not addressed either the choice of parameters or the selective factors involved in the physical relationships existing between parameters. It is suggested that the identification of a viable mechanism scenario would require a detailed multiparameter selective factor analysis, extending to the investigation of the atmospheric data as well as the solar wind/IMF parameters.

  6. Investigation of possible sun-weather relationships

    Energy Technology Data Exchange (ETDEWEB)

    Businger, S

    1978-01-01

    Statistical correlations between anomalous solar activity (as denoted by large solar flares, active plages, and interplanetary magnetic sector boundaries) and the circulation of the troposphere are reviewed. Two indices (measuring atmospheric vorticity and mean zonal geostrophic flow in the northern hemisphere) are analyzed in an effort to reveal possible sun-weather relationships. The result of this analysis provides no additional statistical evidence for a connection between solar activity and the weather. Finally, physical mechanisms that have been suggested to explain the claimed correlations are discussed.

  7. A Solar Position Sensor Based on Image Vision

    Science.gov (United States)

    Ruelas, Adolfo; Velázquez, Nicolás; Villa-Angulo, Carlos; Rosales, Pedro; Suastegui, José

    2017-01-01

    Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors’ evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays’ direction as well as the tilt and sensor position. The sensor’s characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors. PMID:28758935

  8. Automotive sensors

    Science.gov (United States)

    Marek, Jiri; Illing, Matthias

    2003-01-01

    Sensors are an essential component of most electronic systems in the car. They deliver input parameters for comfort features, engine and emission control as well as for the active and passive safety systems. New technologies such as silicon micromachining play an important role for the introduction of these sensors in all vehicle classes. The importance and use of these sensor technologies in today"s automotive applications will be shown in this article. Finally an outlook on important current developments and new functions in the car will be given.

  9. Piezoceramic Sensors

    CERN Document Server

    Sharapov, Valeriy

    2011-01-01

    This book presents the latest and complete information about various types of piezosensors. A sensor is a converter of the measured physical size to an electric signal. Piezoelectric transducers and sensors are based on piezoelectric effects. They have proven to be versatile tools for the measurement of various processes. They are used for quality assurance, process control and for research and development in many different industries. In each area of application specific requirements to the parameters of transducers and sensors are developed. This book presents the fundamentals, technical des

  10. The Sun and the Earth's Climate

    Directory of Open Access Journals (Sweden)

    Haigh Joanna D.

    2007-10-01

    Full Text Available Variations in solar activity, at least as observed in numbers of sunspots, have been apparent since ancient times but to what extent solar variability may affect global climate has been far more controversial. The subject had been in and out of fashion for at least two centuries but the current need to distinguish between natural and anthropogenic causes of climate change has brought it again to the forefront of meteorological research. The absolute radiometers carried by satellites since the late 1970s have produced indisputable evidence that total solar irradiance varies systematically over the 11-year sunspot cycle, relegating to history the term “solar constant”, but it is difficult to explain how the apparent response to the Sun, seen in many climate records, can be brought about by these rather small changes in radiation. This article reviews some of the evidence for a solar influence on the lower atmosphere and discusses some of the mechanisms whereby the Sun may produce more significant impacts than might be surmised from a consideration only of variations in total solar irradiance.

  11. Seismic Sounding of Convection in the Sun

    CERN Document Server

    Hanasoge, Shravan; Sreenivasan, Katepalli R

    2015-01-01

    Our Sun, primarily composed of ionized hydrogen and helium, has a surface temperature of 5777~K and a radius $R_\\odot \\approx 696,000$ km. In the outer $R_\\odot/3$, energy transport is accomplished primarily by convection. Using typical convective velocities $u\\sim100\\,\\rm{m\\,s^{-1}}$ and kinematic viscosities of order $10^{-4}$ m$^{2}$s$^{-1}$, we obtain a Reynolds number $Re \\sim 10^{14}$. Convection is thus turbulent, causing a vast range of scales to be excited. The Prandtl number, $Pr$, of the convecting fluid is very low, of order $10^{-7}$\\,--\\,$10^{-4}$, so that the Rayleigh number ($\\sim Re^2 Pr$) is on the order of $10^{21}\\,-\\,10^{24}$. Solar convection thus lies in extraordinary regime of dynamical parameters, highly untypical of fluid flows on Earth. Convective processes in the Sun drive global fluid circulations and magnetic fields, which in turn affect its visible outer layers ("solar activity") and, more broadly, the heliosphere ("space weather"). The precise determination of the depth of sola...

  12. Exoplanets Clue to Sun's Curious Chemistry

    Science.gov (United States)

    2009-11-01

    A ground-breaking census of 500 stars, 70 of which are known to host planets, has successfully linked the long-standing "lithium mystery" observed in the Sun to the presence of planetary systems. Using ESO's successful HARPS spectrograph, a team of astronomers has found that Sun-like stars that host planets have destroyed their lithium much more efficiently than "planet-free" stars. This finding does not only shed light on the lack of lithium in our star, but also provides astronomers with a very efficient way of finding stars with planetary systems. "For almost 10 years we have tried to find out what distinguishes stars with planetary systems from their barren cousins," says Garik Israelian, lead author of a paper appearing this week in the journal Nature. "We have now found that the amount of lithium in Sun-like stars depends on whether or not they have planets." Low levels of this chemical element have been noticed for decades in the Sun, as compared to other solar-like stars, and astronomers have been unable to explain the anomaly. The discovery of a trend among planet-bearing stars provides a natural explanation to this long-standing mystery. "The explanation of this 60 year-long puzzle is for us rather simple," adds Israelian. "The Sun lacks lithium because it has planets." This conclusion is based on the analysis of 500 stars, including 70 planet-hosting stars. Most of these stars were monitored for several years with ESO's High Accuracy Radial Velocity Planet Searcher. This spectrograph, better known as HARPS, is attached to ESO's 3.6-metre telescope and is the world's foremost exoplanet hunter. "This is the best possible sample available to date to understand what makes planet-bearing stars unique," says co-author Michel Mayor. The astronomers looked in particular at Sun-like stars, almost a quarter of the whole sample. They found that the majority of stars hosting planets possess less than 1% of the amount of lithium shown by most of the other stars

  13. A new perspective on quiet Sun magnetism

    Institute of Scientific and Technical Information of China (English)

    LITES Bruce William

    2009-01-01

    The Hinode mission has provided us with a new, quantitative view of the magnetism of the quiet Sun. It has revealed that the quiet internetwork areas are blanketed by horizontal fields that appear at first sight to have more flux than the vertical fields resolved on the same 0.3″ size scale. These measurements point to the possibility that the horizontal fields might be the primary source of the "hidden turbulent flux" of the quiet Sun anticipated from Hanle effect depolarization. In this paper, evidence is presented suggesting that the "seething" horizontal fields observed by Harvey in 2007 and the horizontal fields revealed by Hinode are the same phenomenon. Because the seething fields appear to be of uniform fluctuation over the whole disk, the phenomenon is most likely not associated with the dynamo source of solar activity. Thus, the small-scale "hidden turbulent flux" lends support to the notion of a local solar dynamo acting on granular sizes and time scales.

  14. Promoting sun safety among zoo visitors.

    Science.gov (United States)

    Mayer, J A; Lewis, E C; Eckhardt, L; Slymen, D; Belch, G; Elder, J; Engelberg, M; Eichenfield, L; Achter, A; Nichols, T; Walker, K; Kwon, H; Talosig, M; Gearen, C

    2001-09-01

    Each year, millions of children visit zoological parks, where they are exposed to long bouts of ultraviolet radiation (UVR). We conducted a study in the winter and replicated it in the summer to evaluate an intervention for reducing UVR exposure during the zoo visit. Each study used a nonequivalent control group design: one zoological site received the intervention and a second received evaluation only. Key outcome measures consisted of observed prevalence of hat use by exiting children (N = 8,721 and 8,524, respectively, in winter and summer studies) and purchase rates of sunscreen and hats in zoo gift shops. Intervention consisted of tip sheets for parents, children's activities, prompts, and discounts off the price of sunscreen and sun-protective hats. In the summer study, sales of both sunscreen and target hats increased significantly at the intervention site relative to the control site, whereas in the winter study, only sunscreen sales at the intervention site had a significant (relative) increase. Children's hat use increased significantly at the intervention site, but only in the winter study. The multicomponent program was effective in promoting purchases of sun-safe items, but its impact on children's hat use was inconclusive. Copyright 2001 American Health Foundation and Academic Press.

  15. Light Work: Contemporary Artists Consider the Sun

    Science.gov (United States)

    Cummins, Rebecca

    2005-01-01

    Modern day life and timekeepers have profoundly affected the way we conceptualize time and our position in the universe. Over the past year, I have been investigating the apparent movement of the Sun both sculpturally and photographically. In this paper, I discuss my collaborations with Woody Sullivan and highlight several of the sundials, both gigantic and intimate, created by University of Washington students in the class Where is Noon? Regarding Giant Sundials that we co-taught in Spring 2003. I have continued to develop artistic approaches to solar events. Some of these sunworks have not been designed specifically to measure the exact time of day as a classic sundial does, but to stimulate a greater awareness of our subjective and paradoxical relationship to nature and technology. Other, almost domestic, poetic, humorous or intimate ways of interacting with science and technology are being actively explored. I will also provide a background to previous works I have done in relation to the Sun and optics, and briefly mention artists who are using astronomical events as a point of departure.

  16. Two sun-like superflare stars rotating as slow as the Sun*

    Science.gov (United States)

    Nogami, Daisaku; Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Shibata, Kazunari

    2014-04-01

    We report on the results of high dispersion spectroscopy of two "superflare stars," KIC 9766237 and KIC 9944137 with Subaru/HDS. Superflare stars are G-type main sequence stars, but show gigantic flares compared to the Sun, which have recently been discovered in the data obtained with the Kepler spacecraft. Though most of these stars are thought to have a rotation period shorter than 10 d on the basis of photometric variabilities, the two targets of the present paper are estimated to have rotation periods of 21.8 d and 25.3 d. Our spectroscopic results clarified that these stars have stellar parameters similar to those of the Sun in terms of the effective temperature, surface gravity, and metallicity. The projected rotational velocities derived by us are consistent with the photometric rotation period, indicating a fairly high inclination angle. The average strength of the magnetic field on the surface of these stars are estimated to be 1-20 G, by using the absorption line of Ca II 8542. We could not detect any hint of binarity in our spectra, although more data are needed to firmly rule out the presence of an unseen low-mass companion. These results claim that the spectroscopic properties of these superflare stars are very close to those of the Sun, and support the hypothesis that the Sun might cause a superflare.

  17. The transit of Venus enterprise in Victorian Britain

    CERN Document Server

    Ratcliff, Jessica

    2008-01-01

    In nineteenth century, the British Government spent money measuring the distance between the earth and the sun using observations of the transit of Venus. This book presents a narrative of the two Victorian transit programmes. It draws out their cultural significance and explores the nature of 'big science' in late-Victorian Britain.

  18. The Effect of Recent Venus Transit on Earths Atmosphere

    OpenAIRE

    H. P. Sardar; Mandal, S. K.; Mandal, P. K.; Guha, A.; Sarkar, S. K.; Sarkar, B. K.; Adhikari, S. K.; De, B. K.; S S; Ray, M.

    2006-01-01

    Some experiments on June 8, 2004, the day of transit of Venus across the Sun, were undertaken at Kolkata (latitude: 23034? N) to observe effect, if any, of transit of Venus on FWF, ELF and VLF amplitudes. The result shows good correlation between their temporal variations during the transit. The observation was unbelievable as the Venus subtends only 1/32th of the cone subtended by Sun on Earth. This anomaly may be explained on the assumption that the height of Venusian atmosphere with high c...

  19. The effect of recent Venus transit on Earths atmosphere

    OpenAIRE

    H. P. Sardar; Mandal, S. K.; Mandal, P. K.; Guha, A.; Sarkar, S. K.; Sarkar, B. K.; Adhikari, S. K.; De, B. K.; S S; Ray, M.

    2006-01-01

    Some experiments on June 8, 2004, the day of transit of Venus across the Sun, were undertaken at Kolkata (latitude: 22°34lN) to observe the effect, if any, of transit of Venus on FWF, ELF and VLF amplitudes. The result shows a good correlation between their temporal variations during the transit. The observation was unbelievable as the Venus subtends only 1/32th of the cone subtended by Sun on Earth. This anomaly may be explained on the assumption that the height of Venusian atmosphere with h...

  20. Vibrissa Sensor

    Science.gov (United States)

    2016-09-30

    Docket No. 300119 1 of 11 VIBRISSA SENSOR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention provides a... measured as strain. [0009] Thus, there is a need for a sensor utilizing a vibrissa that can detect dynamic and high frequency movement of the

  1. Vibration sensors

    Science.gov (United States)

    Gupta, Amita; Singh, Ranvir; Ahmad, Amir; Kumar, Mahesh

    2003-10-01

    Today, vibration sensors with low and medium sensitivities are in great demand. Their applications include robotics, navigation, machine vibration monitoring, isolation of precision equipment & activation of safety systems e.g. airbags in automobiles. Vibration sensors have been developed at SSPL, using silicon micromachining to sense vibrations in a system in the 30 - 200 Hz frequency band. The sensing element in the silicon vibration sensor is a seismic mass suspended by thin silicon hinges mounted on a metallized glass plate forming a parallel plate capacitor. The movement of the seismic mass along the vertical axis is monitored to sense vibrations. This is obtained by measuring the change in capacitance. The movable plate of the parallel plate capacitor is formed by a block connected to a surrounding frame by four cantilever beams located on sides or corners of the seismic mass. This element is fabricated by silicon micromachining. Several sensors in the chip sizes 1.6 cm x 1.6 cm, 1 cm x 1 cm and 0.7 cm x 0.7 cm have been fabricated. Work done on these sensors, techniques used in processing and silicon to glass bonding are presented in the paper. Performance evaluation of these sensors is also discussed.

  2. Perry, Kelvin, and the age of the sun

    Science.gov (United States)

    Tipler, Frank J.

    2013-04-01

    Lord Kelvin argued that the Sun had to be between 20 and 100 million years old, based on the assumption that the Sun's energy source was gravitational contraction. As everyone now knows, the Sun's actual power source is the thermonuclear fusion of hydrogen into helium. But Kelvin's number is based on a physical assumption for which he could give no justification: the Sun's density is approximately constant. Had Kelvin assumed instead that the Sun had a small core near a black hole radius - an assumption allowed by the knowledge of physicists at the end of the nineteenth century - he would have obtained an age for the Sun as long as 10 trillion years, completely consistent with the long time scale required for evolution. Conversely, had Kelvin accepted the geologists' time scale, he would have been forced to acknowledge the existence of very dense objects, making it easier for twentieth century astronomers to accept the existence of black holes and neutron stars.

  3. Scalar model of SU(N) glueball \\`a la Heisenberg

    CERN Document Server

    Dzhunushaliev, Vladimir

    2016-01-01

    Nonperturbative model of glueball is studied. The model is based on the nonperturbative quantization technique suggested by Heisenberg. 2- and 4-point Green functions for a gauge potential are expressed in terms of two scalar fields. The first scalar field describes quantum fluctuations of a subgroup $SU(n) \\subset SU(N)$, and the second one describes quantum fluctuations of coset $SU(N) / SU(n)$. An effective Lagrangian for the scalar fields is obtained. The coefficients for all terms in the Lagrangian are calculated, and it is shown that they depend on $\\dim SU(n), \\dim SU(N)$. It is demonstrated that spherically symmetric solution describing the glueball does exist.

  4. Sun One Portal Server体系架构

    Institute of Scientific and Technical Information of China (English)

    王勇泉

    2003-01-01

    目前,门户市场上存在着国内外多种多样的产品,本文主要介绍Sun公司的Sun ONE Portal Servero Sun ONE Portal Server到目前为止,在全球拥有400多个客户,分布于金融、电信、政府、汽车、制造、教育等行业。Sun ONE Portal Server是Sun ONE的重要组成部分。首先,让我们来看看Sun ONE(Sun Open Net Environment)的

  5. New dynamics of the Sun convection zone and global warming

    CERN Document Server

    Bershadskii, A

    2008-01-01

    Solar activity is studied using cluster analysis of the sunspot number time-fluctuations. It is shown that for a Historic period (1850-1932yy) the cluster exponent $\\alpha \\simeq 0.37$ (strong clustering) for the high activity components of the solar cycles, whereas for a Modern period (last seven solar cycles: 1933-2007) the cluster exponent $\\alpha \\simeq 0.50$ (random, white noise-like situation). Then, comparing these results with the corresponding data from the classic laboratory convection experiments it is shown, that for the Historic period emergence of the sunspots in the solar photosphere was strongly dominated by turbulent photospheric convection. For the Modern period, this domination was broken by a new more active dynamics of the inner layers of the convection zone. Then, it is shown that the dramatic change of the sun dynamics in the transitional period (between the Historic and Modern periods, solar cycle 1933-1944yy) had clear detectable impact on the global Earth climate at this period. Name...

  6. QUIET-SUN NETWORK BRIGHT POINT PHENOMENA WITH SIGMOIDAL SIGNATURES

    Energy Technology Data Exchange (ETDEWEB)

    Chesny, D. L.; Oluseyi, H. M. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States); Orange, N. B. [OrangeWave Innovative Science, LLC, Moncks Corner, SC 29461 (United States); Champey, P. R. [Department of Optical Science and Engineering, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2015-12-01

    Ubiquitous solar atmospheric coronal and transition region bright points (BPs) are compact features overlying strong concentrations of magnetic flux. Here, we utilize high-cadence observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to provide the first observations of extreme ultraviolet quiet-Sun (QS) network BP activity associated with sigmoidal structuring. To our knowledge, this previously unresolved fine structure has never been associated with such small-scale QS events. This QS event precedes a bi-directional jet in a compact, low-energy, and low-temperature environment, where evidence is found in support of the typical fan-spine magnetic field topology. As in active regions and micro-sigmoids, the sigmoidal arcade is likely formed via tether-cutting reconnection and precedes peak intensity enhancements and eruptive activity. Our QS BP sigmoid provides a new class of small-scale structuring exhibiting self-organized criticality that highlights a multi-scaled self-similarity between large-scale, high-temperature coronal fields and the small-scale, lower-temperature QS network. Finally, our QS BP sigmoid elevates arguments for coronal heating contributions from cooler atmospheric layers, as this class of structure may provide evidence favoring mass, energy, and helicity injections into the heliosphere.

  7. Quiet-Sun Network Bright Point Phenomena with Sigmoidal Signatures

    Science.gov (United States)

    Chesny, D. L.; Oluseyi, H. M.; Orange, N. B.; Champey, P. R.

    2015-12-01

    Ubiquitous solar atmospheric coronal and transition region bright points (BPs) are compact features overlying strong concentrations of magnetic flux. Here, we utilize high-cadence observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to provide the first observations of extreme ultraviolet quiet-Sun (QS) network BP activity associated with sigmoidal structuring. To our knowledge, this previously unresolved fine structure has never been associated with such small-scale QS events. This QS event precedes a bi-directional jet in a compact, low-energy, and low-temperature environment, where evidence is found in support of the typical fan-spine magnetic field topology. As in active regions and micro-sigmoids, the sigmoidal arcade is likely formed via tether-cutting reconnection and precedes peak intensity enhancements and eruptive activity. Our QS BP sigmoid provides a new class of small-scale structuring exhibiting self-organized criticality that highlights a multi-scaled self-similarity between large-scale, high-temperature coronal fields and the small-scale, lower-temperature QS network. Finally, our QS BP sigmoid elevates arguments for coronal heating contributions from cooler atmospheric layers, as this class of structure may provide evidence favoring mass, energy, and helicity injections into the heliosphere.

  8. Astrobiological Molecularly Imprinted Polymer Sensors

    Science.gov (United States)

    Izenberg, N. R.; Murray, G. M.; van Houten, K. A.; Hofstra, A. A.

    2005-12-01

    Development of Molecularly Imprinted Polymer (MIP) sensors for astrobiology is intended to provide a new class of microlaboratory sensors compatible with other life or biomarker detection. Molecular imprinting is a process for making selective binding sites in synthetic polymers. The process may be approached by designing the recognition site or by simply choosing monomers that may have favorable interactions with the imprinting molecule. We are working to apply this methodology to astrobiology for development of a reliable, low cost, low mass, low power consumption sensor technology for quantitative in-situ analysis of biochemistry, biomarkers, and other indicators of astrobiological importance. Specific goals of the project are: 1) To develop a general methodology and specific methods for MIP-based sensor construction. The overall methodology will guide procedures for design and testing of any desired sensor. Specific methods will be applied to key families and specific species of astrobiological interest, i.e., alkanes (and Polycyclic aromatic hydrocarbons - PAHs), amino acids, steroids, and hopanes; 2) To construct and characterize the general family and specific species sensors. We will test for accuracy, precision, interferences, and limitations of the sensor against blanks, standards, and known terrestrial biological environment samples. Additional testing will determine sturdiness and longevity of sensors after exposure to transit conditions (launch and space environment), and at potential target environments (pressure, temperature, pH, etc.); and 3) To construct and demonstrate the combination of multiple sensors into a viable prototype instrument, and roadmap the expansion of potential instrument capabilities and exploration of the ultimate environmental limitations of the technology, and the necessary changes and additions to create a mission-ready instrument. Initial work has resulted successful detection of aqueous alanine (D and L) with simple MIP

  9. Analysis of aerosol properties derived from sun photometer and lidar over Dunhuang radiometric calibration site

    Science.gov (United States)

    Chen, Lin; Jing, Yingying; Zhang, Peng; Hu, Xiuqing

    2016-05-01

    Duhuang site has been selected as China Radiation Calibration Site (CRCS) for Remote Sensing Satellite Sensors since 1996. With the economic development of Dunhuang city, the ambient of the radiation calibration field has changed in recent years. Taking into account the key role of aerosol in radiometric calibration, it is essential to investigate the aerosol optical properties over Dunhuang radiometric calibration site. In this paper, the CIMEL sun photometer (CE-318) and Mie-scattering Lidar are simultaneously used to measure aerosol optical properties in Dunhuang site. Data from aerosol-bands of sun photometer are used in a Langley method to determine spectral optical depths of aerosol. And Lidar is utilized to obtain information of vertical profile and integrated aerosol optical depths at different heights. The results showed that the aerosol optical depth at 500 nm wavelength during the in-situ measurement campaigns varied from 0.1 to 0.3 in Dunhuang site. And the observation results also indicated that high aerosol concentration layer mostly located at the height of about 2~4 km. These results implies that the aerosol concentration of atmosphere in Dunhuang was relatively small and suitable for in-flight calibration for remote sensing satellite sensors.

  10. Sun Protection Belief Clusters: Analysis of Amazon Mechanical Turk Data.

    Science.gov (United States)

    Santiago-Rivas, Marimer; Schnur, Julie B; Jandorf, Lina

    2016-12-01

    This study aimed (i) to determine whether people could be differentiated on the basis of their sun protection belief profiles and individual characteristics and (ii) explore the use of a crowdsourcing web service for the assessment of sun protection beliefs. A sample of 500 adults completed an online survey of sun protection belief items using Amazon Mechanical Turk. A two-phased cluster analysis (i.e., hierarchical and non-hierarchical K-means) was utilized to determine clusters of sun protection barriers and facilitators. Results yielded three distinct clusters of sun protection barriers and three distinct clusters of sun protection facilitators. Significant associations between gender, age, sun sensitivity, and cluster membership were identified. Results also showed an association between barrier and facilitator cluster membership. The results of this study provided a potential alternative approach to developing future sun protection promotion initiatives in the population. Findings add to our knowledge regarding individuals who support, oppose, or are ambivalent toward sun protection and inform intervention research by identifying distinct subtypes that may best benefit from (or have a higher need for) skin cancer prevention efforts.

  11. Interstellar Dust Close to the Sun

    CERN Document Server

    Frisch, Priscilla C

    2012-01-01

    The low density interstellar medium (ISM) close to the Sun and inside of the heliosphere provides a unique laboratory for studying interstellar dust grains. Grain characteristics in the nearby ISM are obtained from observations of interstellar gas and dust inside of the heliosphere and the interstellar gas towards nearby stars. Comparison between the gas composition and solar abundances suggests that grains are dominated by olivines and possibly some form of iron oxide. Measurements of the interstellar Ne/O ratio by the Interstellar Boundary Explorer spacecraft indicate that a high fraction of interstellar oxygen in the ISM must be depleted onto dust grains. Local interstellar abundances are consistent with grain destruction in ~150 km/s interstellar shocks, provided that the carbonaceous component is hydrogenated amorphous carbon and carbon abundances are correct. Variations in relative abundances of refractories in gas suggest variations in the history of grain destruction in nearby ISM. The large observed ...

  12. Imaging convection and magnetism in the sun

    CERN Document Server

    Hanasoge, Shravan

    2015-01-01

    This book reviews the field of helioseismology and its outstanding challenges and also offers a detailed discussion of the latest computational methodologies. The focus is on the development and implementation of techniques to create 3-D images of convection and magnetism in the solar interior and to introduce the latest computational and theoretical methods to the interested reader. With the increasing availability of computational resources, demand for greater accuracy in the interpretation of helioseismic measurements and the advent of billion-dollar instruments taking high-quality observations, computational methods of helioseismology that enable probing the 3-D structure of the Sun have increasingly become central. This book will benefit students and researchers with proficiency in basic numerical methods, differential equations and linear algebra who are interested in helioseismology.

  13. Choosing an expected sun protection factor value.

    Science.gov (United States)

    Sica, John R; Caswell, Michael

    2015-01-01

    Sun protection factor, SPF, is a measure of the efficacy of a topical sunscreen product; the higher the SPF, the greater the blockage of ultraviolet-induced erythema. While there are several methods to determine SPF, the Food and Drug Administration (FDA) methods are unique. The FDA methods define the label SPF value as the largest whole integer after subtracting an "A" value from the mean SPF. The A value, composed of the product of the upper 5% point of the t-distribution and the standard deviation (SD), divided by √(n), where n equals the number of subjects, has a significant impact on the label SPF value. Two examples explore this impact. Development of strategies to mitigate the impact of A using expected SPF values are explored using historical clinical trial data. A more enlightened choice of expected SPF values is shown to lead to higher label SPF values.

  14. Coronal Mass Ejections: From Sun to Earth

    Science.gov (United States)

    Patsourakos, S.

    2016-06-01

    Coronal Mass Ejections (CMEs) are gigantic expulsions of magnetized plasmas from the solar corona into the interplanetary (IP) space. CMEs spawn ~ 1015 gr of mass and reach speeds ranging between several hundred to a few thousand km/s (e.g., Gopalswamy et al. 2009; Vourlidas et al. 2010). It takes 1-5 days for a CME to reach Earth. CMEs are one of the most energetic eruptive manifestations in the solar system and are major drivers of space weather via their magnetic fields and energetic particles, which are accelerated by CME-driven shocks. In this review we give a short account of recent, mainly observational, results on CMEs from the STEREO and SDO missions which include the nature of their pre-eruptive and eruptive configurations and the CME propagation from Sun to Earth. We conclude with a discussion of the exciting capabilities in CME studies that will soon become available from new solar and heliospheric instrumentation.

  15. Earth, Moon, Sun, and CV Accretion Disks

    CERN Document Server

    Montgomery, M M

    2009-01-01

    Net tidal torque by the secondary on a misaligned accretion disk, like the net tidal torque by the Moon and the Sun on the equatorial bulge of the spinning and tilted Earth, is suggested by others to be a source to retrograde precession in non-magnetic, accreting Cataclysmic Variable (CV) Dwarf Novae systems that show negative superhumps in their light curves. We investigate this idea in this work. We generate a generic theoretical expression for retrograde precession in spinning disks that are misaligned with the orbital plane. Our generic theoretical expression matches that which describes the retrograde precession of Earths' equinoxes. By making appropriate assumptions, we reduce our generic theoretical expression to those generated by others, or to those used by others, to describe retrograde precession in protostellar, protoplanetary, X-ray binary, non-magnetic CV DN, quasar and black hole systems. We find that differential rotation and effects on the disk by the accretion stream must be addressed. Our a...

  16. Convectively driven vortex flows in the Sun

    CERN Document Server

    Bonet, J A; Almeida, J Sanchez; Cabello, I; Domingo, V

    2008-01-01

    We have discovered small whirlpools in the Sun, with a size similar to the terrestrial hurricanes (<~0.5 Mm). The theory of solar convection predicts them, but they had remained elusive so far. The vortex flows are created at the downdrafts where the plasma returns to the solar interior after cooling down, and we detect them because some magnetic bright points (BPs) follow a logarithmic spiral in their way to be engulfed by a downdraft. Our disk center observations show 0.009 vortexes per Mm^2, with a lifetime of the order of 5 min, and with no preferred sense of rotation. They are not evenly spread out over the surface, but they seem to trace the supergranulation and the mesogranulation. These observed properties are strongly biased by our type of measurement, unable to detect vortexes except when they are engulfing magnetic BPs.

  17. Substructure of Quiet Sun Bright Points

    CERN Document Server

    Andic, Aleksandra; Goode, Phillip R

    2010-01-01

    Since photospheric bright points (BPs) were first observed, there has been a question as to how are they structured. Are they just single flux tubes or a bundle of the flux-tubes? Surface photometry of the quiet Sun (QS) has achieved resolution close to 0.1" with the New Solar Telescope at Big Bear Solar Observatory. This resolution allowed us to detect a richer spectrum of BPs in the QS. The smallest BPs we observed with TiO 705.68 nm were 0.13", and we were able to resolve individual components in some of the BPs clusters and ribbons observed in the QS, showing that they are composed of the individual BPs. Average size of observed BPs was 0.22".

  18. Cartography of the sun and the stars

    CERN Document Server

    Neiner, Coralie

    2016-01-01

    The mapping of the surface of stars requires diverse skills, analysis techniques and advanced modeling, i.e. the collaboration of scientists in various specialties. This volume gives insights into new techniques allowing for the first time to obtain resolved images of stars. It takes stock of what has been achieved so far in Chile, on the ESO VLTI instrument or, in the States, on the CHARA instrument. In recent times interferometry, combined with adaptive optics has allowed to reconstruct images of stars. Besides the Sun (of course) by now five stars have been resolved in detail. In addition to interferometry, this book highlights techniques used for mapping the surfaces of stars using photometry made by space observatories; Zeeman- and Doppler Imaging; mapping the surface element abundances via spectroscopy. This book will also take stock of the best images of the  solar surface, made by connecting the differential rotation to the underlying physical parameters derived from helioseismology. Recent measureme...

  19. MEMS sensor technology

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhuangde

    2012-01-01

    Since 1992 the author has led research group in Xi'an Jiaotong University to investigate and develop microelectro mechanical systems (MEMS) sensors, including pressure sensor, acceleration sensor, gas sensor, viscosity & density sensor, polymerase chain reaction (PCR) chip and integrated sensor etc. This paper introduces the technologies and research results related to MEMS sensors we achieved in the last 20 years.

  20. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere VII. Further Insights into the Chromosphere and Corona

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available In the liquid metallic hydrogen model of the Sun, the chromosphere is responsible for the capture of atomic hydrogen in the solar atmosphere and its eventual re-entry onto the photospheric surface (P.M. Robitaille. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere IV. On the Nature of the Chromosphere. Prog. Phys., 2013, v. 3, L15–L21. As for the corona, it represents a diffuse region containing both gaseous plasma and condensed matter with elevated electron affinity (P.M. Robitaille. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere V. On the Nature of the Corona. Prog. Phys., 2013, v. 3, L22–L25. Metallic hydrogen in the corona is thought to enable the continual harvest of electrons from the outer reaches of the Sun, thereby preserving the neutrality of the solar body. The rigid rotation of the corona is offered as the thirty-third line of evidence that the Sun is comprised of condensed matter. Within the context of the gaseous models of the Sun, a 100 km thick transition zone has been hypothesized to exist wherein temperatures increase dramatically from 104–106 K. Such extreme transitional temperatures are not reasonable given the trivial physical scale of the proposed transition zone, a region adopted to account for the ultra-violet emission lines of ions such as C IV, O IV, and Si IV. In this work, it will be argued that the transition zone does not exist. Rather, the intermediate ionization states observed in the solar atmosphere should be viewed as the result of the simultaneous transfer of protons and electrons onto condensed hydrogen structures, CHS. Line emissions from ions such as C IV, O IV, and Si IV are likely to be the result of condensation reactions, manifesting the involvement of species such as CH4, SiH4, H3O+ in the synthesis of CHS in the chromosphere. In addition, given the presence of a true solar surface at the level of the photosphere in the liquid metallic hydrogen model

  1. Sensor Fusion of Force and Acceleration for Robot Force Control

    OpenAIRE

    Gámez García, Javier; Robertsson, Anders; Gómez Ortega, Juan; Johansson, Rolf

    2004-01-01

    In this paper, robotic sensor fusion of acceleration and force measurement is considered. We discuss the problem of using accelerometers close to the end-effectors of robotic manipulators and how it may improve the force control performance. We introduce a new model-based observer approach to sensor fusion of information from various different sensors. During contact transition, accelerometers and force sensors play a very important role and it can overcome many of the difficulties of uncerta...

  2. Modeling temperature and stress in rocks exposed to the sun

    Science.gov (United States)

    Hallet, B.; Mackenzie, P.; Shi, J.; Eppes, M. C.

    2012-12-01

    The potential contribution of solar-driven thermal cycling to the progressive breakdown of surface rocks on the Earth and other planets is recognized but under studied. To shed light on this contribution we have launched a collaborative study integrating modern instrumental and numerical approaches to define surface temperatures, stresses, strains, and microfracture activity in exposed boulders, and to shed light on the thermo-mechanical response of boulders to diurnal solar exposure. The instrumental portion of our study is conducted by M. Eppes and coworkers who have monitored the surface and environmental conditions of two ~30 cm dia. granite boulders (one in North Carolina, one in New Mexico) in the field for one and tow years, respectively. Each boulder is instrumented with 8 thermocouples, 8 strain gauges, a surface moisture sensor and 6 acoustic emission (AE) sensors to monitor microfracture activity continuously and to locate it within 2.5 cm. Herein, we focus on the numerical modeling. Using a commercially available finite element program, MSC.Marc®2008r1, we have developed an adaptable, realistic thermo-mechanical model to investigate quantitatively the temporal and spatial distributions of both temperature and stress throughout a boulder. The model accounts for the effects of latitude and season (length of day and the sun's path relative to the object), atmospheric damping (reduction of solar radiation when traveling through the Earth's atmosphere), radiative interaction between the boulder and its surrounding soil, secondary heat exchange of the rock with air, and transient heat conduction in both rock and soil. Using representative thermal and elastic rock properties, as well as realistic representations of the size, shape and orientation of a boulder instrumented in the field in North Carolina, the model is validated by comparison with direct measurements of temperature and strain on the surface of one boulder exposed to the sun. Using the validated

  3. An automated method for the evaluation of the pointing accuracy of Sun-tracking devices

    Science.gov (United States)

    Baumgartner, Dietmar J.; Pötzi, Werner; Freislich, Heinrich; Strutzmann, Heinz; Veronig, Astrid M.; Rieder, Harald E.

    2017-03-01

    The accuracy of solar radiation measurements, for direct (DIR) and diffuse (DIF) radiation, depends significantly on the precision of the operational Sun-tracking device. Thus, rigid targets for instrument performance and operation have been specified for international monitoring networks, e.g., the Baseline Surface Radiation Network (BSRN) operating under the auspices of the World Climate Research Program (WCRP). Sun-tracking devices that fulfill these accuracy requirements are available from various instrument manufacturers; however, none of the commercially available systems comprise an automatic accuracy control system allowing platform operators to independently validate the pointing accuracy of Sun-tracking sensors during operation. Here we present KSO-STREAMS (KSO-SunTRackEr Accuracy Monitoring System), a fully automated, system-independent, and cost-effective system for evaluating the pointing accuracy of Sun-tracking devices. We detail the monitoring system setup, its design and specifications, and the results from its application to the Sun-tracking system operated at the Kanzelhöhe Observatory (KSO) Austrian radiation monitoring network (ARAD) site. The results from an evaluation campaign from March to June 2015 show that the tracking accuracy of the device operated at KSO lies within BSRN specifications (i.e., 0.1° tracking accuracy) for the vast majority of observations (99.8 %). The evaluation of manufacturer-specified active-tracking accuracies (0.02°), during periods with direct solar radiation exceeding 300 W m-2, shows that these are satisfied in 72.9 % of observations. Tracking accuracies are highest during clear-sky conditions and on days where prevailing clear-sky conditions are interrupted by frontal movement; in these cases, we obtain the complete fulfillment of BSRN requirements and 76.4 % of observations within manufacturer-specified active-tracking accuracies. Limitations to tracking surveillance arise during overcast conditions and

  4. Transit infrared spectroscopy of the hot neptune around GJ 436 with the Hubble Space Telescope

    CERN Document Server

    Pont, F; Knutson, H; Holman, M; Charbonneau, D

    2008-01-01

    The nearby transiting system GJ 436b offers a unique opportunity to probe the structure and atmosphere of an extra-solar "hot Neptune". In this Letter, we present the main results of observations covering two transit events with the NICMOS camera on the Hubble Space Telescope. The data consist in high-cadence time series of grism spectra covering the 1.1-1.9 micron spectral range. We find Rpl=4.04 +- 0.10 R_earth and R_*= 0.446 +- 0.011 R_sun for the planet and star radius, confirming and improving earlier measurements with ground-based photometry and a Spitzer lightcurve at 8 microns, as opposed to a much higher value obtained with the Fine Guidance Sensor on the Hubble Space Telescope. We measure no departure from strict periodicity in the transits to the level of ~7 seconds. This strongly disfavours the proposed explanation of the orbital eccentricity of GJ 436b in terms of the perturbation by another close-by planet. We measure a flat transmission spectrum at the level of a few parts per 10'000 in flux, w...

  5. Celestial shadows eclipses, transits, and occultations

    CERN Document Server

    Westfall, John

    2015-01-01

    Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced re...

  6. Sun-Earth Day 2005: Ancient Observatories: Timeless Knowledge

    Science.gov (United States)

    Thieman, J. R.; Cline, T.; Lewis, E.; Hawkins, I.; Odenwald, S.; Mayo, L.

    2005-05-01

    The NASA Sun-Earth Connection Education Forum (SECEF) annually promotes an event called Sun-Earth Day. For Sun-Earth Day 2005 SECEF has selected a theme called "Ancient Observatories: Timeless Knowledge. This year's Sun-Earth Day theme is your ticket to a fascinating journey through time as we explore centuries of sun watching by a great variety of cultures. From ancient solar motion tracking to modern solar activity monitoring the Sun has always occupied an important spot in mankind's quest to understand the Universe. Sun-Earth Day events usually are centered on the spring equinox around March 21, but this year there has already been a webcast from the San Francisco Exploratorium and the Native American ruins at Chaco Canyon, New Mexico on the day of winter solstice 2004. There will be another webcast on March 20 live from Chichen Itza, Mexico highlighting the solar alignment that makes a serpent appear on one of the ancient pyramids. The website http://sunearthday.nasa.gov has been developed to provide the necessary resources and opportunities for participation by scientists and educators in giving school or general public programs about Sun-Earth Day. The goal is to involve as much of the student population and the public in this event as possible and to help them understand the importance of the Sun for ancient and modern peoples. Through engaging activities available on the website, classrooms and museums can create their own event or participate in one of the opportunities we make available. Scientists, educators, amateur astronomers, and museums are invited to register on the website to receive a free packet of materials about Sun-Earth Day for use in making presentations or programs about the event. Past and future Sun-Earth Days will be discussed as well.

  7. Sun Protection Policies of Australian Primary Schools in a Region of High Sun Exposure

    Science.gov (United States)

    Harrison, S. L.; Garzón-Chavez, D. R.; Nikles, C. J.

    2016-01-01

    Queensland, Australia has the highest rates of skin cancer globally. Predetermined criteria were used to score the comprehensiveness of sun protection policies (SPP) of primary schools across Queensland. SPP were sought for schools in 10 regions (latitude range 16.3°S-28.1°S) from 2011 to 2014. Of the 723 schools sampled, 90.9% had a written SPP…

  8. TESIS experiment on XUV imaging spectroscopy of the Sun onboard the CORONAS-PHOTON satellite

    Science.gov (United States)

    Kuzin, S. V.; Zhitnik, I. A.; Bogachev, S. A.; Shestov, S. V.; Bugaenko, O. I.; Suhodrev, N. K.; Pertsov, A. A.; Mitrofanov, A. V.; Ignat'ev, A. P.; Slemzin, V. A.

    We present a brief description of new complex of space telescopes and spectrographs, TESIS, which will be placed aboard the CORONAS-PHOTON satellite. The complex is intended for high-resolution imaging observation of full Sun in the coronal spectral lines and in the spectral lines of the solar transition region. TESIS will be launched at the end of 2007 - early of 2008. About 25 % of the daily TESIS images will be free for use and for downloading from the TESIS data center that is planned to open 2 months before the TESIS launching at http://www.tesis.lebedev.ru

  9. Polar Magnetic Field Reversals of the Sun in Maunder Minimum

    Indian Academy of Sciences (India)

    V. I. Makarov; A. G. Tlatov

    2000-09-01

    A possible scenario of polar magnetic field reversal of the Sun during the Maunder Minimum (1645-1715) is discussed using data of magnetic field reversals of the Sun for 1880-1991 and the 14C content variations in the bi-annual rings of the pine-trees in 1600-1730 yrs.

  10. Quadrant to Measure the Sun's Altitude

    Science.gov (United States)

    Windsor, A Morgan, Jr.

    2013-01-01

    The changing altitude of the Sun (either over the course of a day or longer periods) is a phenomenon that students do not normally appreciate. However, the altitude of the Sun affects many topics in disciplines as diverse as astronomy, meteorology, navigation, or horology, such as the basis for seasons, determination of latitude and longitude, or…

  11. Sun avoidance strategies at the Large Millimeter Telescope

    Science.gov (United States)

    Souccar, Kamal; Smith, David R.; Schloerb, F. Peter; Wallace, Gary

    2016-07-01

    The Large Millimeter Telescope observatory is extending its night time operation to the day time. A sun avoidance strategy was therefore implemented in the control system in real-time to avoid excessive heating and damage to the secondary mirror and the prime focus. The LMT uses an "on-the-fly" trajectory generator that receives as input the target location of the telescope and in turn outputs a commanded position to the servo system. The sun avoidance strategy is also implemented "on-the-fly" where it intercepts the input to the trajectory generator and alters that input to avoid the sun. Two sun avoidance strategies were explored. The first strategy uses a potential field approach where the sun is represented as a high-potential obstacle in the telescope's workspace and the target location is represented as a low-potential goal. The potential field is repeatedly calculated as the sun and the telescope move and the telescope follows the induced force by this field. The second strategy is based on path planning using visibility graphs where the sun is represented as a polygonal obstacle and the telescope follows the shortest path from its actual position to the target location via the vertices of the sun's polygon. The visibility graph approach was chosen as the favorable strategy due to the efficiency of its algorithm and the simplicity of its computation.

  12. Relationship Factors and Couples' Engagement in Sun Protection

    Science.gov (United States)

    Manne, S. L.; Coups, E. J.; Kashy, D. A.

    2016-01-01

    Individuals may be more motivated to adopt health practices if they consider the benefits of these behaviors for their close relationships. The goal of this study was to examine couple concordance with sun protection and use the interdependence and communal coping theory to evaluate the role of relationship factors in sun protection. One hundred…

  13. Regular Biology Students Learn Like AP Students with SUN

    Science.gov (United States)

    Batiza, Ann; Luo, Wen; Zhang, Bo; Gruhl, Mary; Nelson, David; Hoelzer, Mark; Ning, Ling; Roberts, Marisa; Knopp, Jonathan; Harrington, Tom; LaFlamme, Donna; Haasch, Mary Anne; Vogt, Gina; Goodsell, David; Marcey, David

    2016-01-01

    The SUN approach to biological energy transfer education is fundamentally different from past practices that trace chemical and energy inputs and outputs. The SUN approach uses a hydrogen fuel cell to convince learners that electrons can move from one substance to another based on differential attraction. With a hydrogen fuel cell, learners can…

  14. Wien's Law and the Temperature of the Sun

    Science.gov (United States)

    Biermann, Mark L.; Katz, Debora M.; Aho, Robert; Diaz-Barriga, James; Petron, Jerome

    2002-10-01

    A simple approach is used in an attempt to determine the temperature of the sun by modeling the sun as a blackbody radiator and applying Wein's Law. Apparently excellent results are obtained, but the results are false as a consequence of two corrections which cancel out.

  15. Mr. Sun Laiyan Appointed as Administrator of CNSA

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The State Council of the People's Republic of China announced on April 23, 2004 that Mr. Sun Laiyan was appointed to be the Administrator of China National Space Administration (CNSA). Mr. Luan Enjie was announced to retire from the office. Mr. Sun Laiyan, born in October 1957, graduated from Xian Communication

  16. Growth and morphogenesis of sun and shade plants

    NARCIS (Netherlands)

    Corre, W.J.

    1984-01-01

    A number of species of sun and shade plants in the vegetative phase were grown in different light intensities, different light qualities (r/fr ratio) and different combinations of light intensity and nutrient supply. Sun and shade species were also grown at various plant densities and in interspecif

  17. Sun Safety Knowledge, Attitudes, and Behaviors among Beachgoing Adolescents

    Science.gov (United States)

    Merten, Julie Williams; Higgins, Sue; Rowan, Alan; Pragle, Aimee

    2014-01-01

    Background: Skin cancer rates are rising and could be reduced with better sun protection behaviors. Adolescent exposure to ultraviolet (UV) radiation is damaging because it can lead to skin cancer. This descriptive study extends understanding of adolescent sun exposure attitudes, knowledge, and behaviors. Methods: A sample of 423 beachgoing…

  18. Transits Probabilities Around Hypervelocity and Runaway Stars

    CERN Document Server

    Fragione, Giacomo

    2016-01-01

    In the blooming field of exoplanetary science, NASA's Kepler Space Telescope has revolutionized our understanding of exoplanets. Kepler's very precise and long-duration photometry is ideal for detecting planetary transits around Sun-like stars. The forthcoming Transiting Exoplanet Survey Satellite (TESS) is expected to continue Kepler's legacy. In this paper, we explore the possibility of detecting planetary transits around hypervelocity and runaway stars, which should host a very compact system as consequence of their turbulent origin. We find that the probability of a multi-planetary transit is $10^{-3}\\lesssim P\\lesssim 10^{-1}$. We therefore need to observe $\\sim 10-1000$ high-velocity stars to spot a transit. We predict that the European Gaia satellite, along with TESS, could spot such transits.

  19. Measuring stellar granulation during planet transits

    CERN Document Server

    Chiavassa, A; Selsis, F; Leconte, J; Von Paris, P; Bordé, P; Magic, Z; Collet, R; Asplund, M

    2016-01-01

    Stellar activity and convection-related surface structures might cause bias in planet detection and characterization that use these transits. Surface convection simulations help to quantify the granulation signal. We used realistic three-dimensional radiative hydrodynamical simulations from the Stagger grid and synthetic images computed with the radiative transfer code Optim3D to model the transits of three prototype planets: a hot Jupiter, a hot Neptune, and a terrestrial planet. We computed intensity maps from RHD simulations of the Sun and a K-dwarf star at different wavelength bands from optical to far-infrared. We modeled the transit using synthetic stellar-disk images and emulated the temporal variation of the granulation intensity. We identified two types of granulation noise that act simultaneously during the planet transit: (i) the intrinsic change in the granulation pattern with timescales smaller than the usual planet transit, and (ii) the fact that the transiting planet occults isolated regions of...

  20. Sun Glint Correction of High and Low Spatial Resolution Images of Aquatic Scenes: a Review of Methods for Visible and Near-Infrared Wavelengths

    Directory of Open Access Journals (Sweden)

    Susan Kay

    2009-10-01

    Full Text Available Sun glint, the specular reflection of light from water surfaces, is a serious confounding factor for remote sensing of water column properties and benthos. This paper reviews current techniques to estimate and remove the glint radiance component from imagery. Methods for processing of ocean color images use statistical sea surface models to predict the glint from the sun and sensor positions and wind data. Methods for higher resolution imaging, used in coastal and shallow water mapping, estimate the glint radiance from the near-infrared signal. The effects of some current methods are demonstrated and possibilities for future techniques are briefly addressed.