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Sample records for polarized feed array

  1. CORPORATE FEED WITH DUAL SEGMENT CIRCULAR POLARIZED ARRAY RECTENNA FOR LOW POWER RF ENERGY HARVESTING

    Directory of Open Access Journals (Sweden)

    CHIA CHAO KANG

    2016-06-01

    Full Text Available This paper focuses on the investigation of the level powers that can be scavenged from the ambient environment by using corporate feed with dual segment circular polarized antenna array . It will converts the received power to direct current (DC. Being a circular polarized antenna, it has higher inductance per unit area, a good Q-factor and compact capability. The design of corporate-series feed rectenna array is to achieve a high gain antenna and maximize the RF energy received by the rectenna system at ultra low power levels. The entire structure was investigated using a combination of harmonic balance nonlinear analysis and full wave electromagnetic field analysis. The results show that 5.0 dBi gain for circular polarized antenna array can be achieved at frequency 956 MHz. When the input power of 20 dBm fed into the transmitting antenna, the maximum distance for radio frequency (RF harvesting is 5.32m. The output DC voltage for various values of incident RF power is also presented. There are noticed reasonable agreements between the simulated and measured result and the works concludes that the investigation of RF energy harvesting system was successful.

  2. SCRLH-TL Based Sequential Rotation Feed Network for Broadband Circularly Polarized Antenna Array

    Directory of Open Access Journals (Sweden)

    B. F. Zong

    2016-04-01

    Full Text Available In this paper, a broadband circularly polarized (CP microstrip antenna array using composite right/left-handed transmission line (SCRLH-TL based sequential rotation (SR feed network is presented. The characteristics of a SCRLH-TL are initially investigated. Then, a broadband and low insertion loss 45º phase shifter is designed using the SCRLH-TL and the phase shifter is employed in constructing a SR feed network for CP antenna array. To validate the design method of the SR feed network, a 2×2 antenna array comprising sequentially rotated coupled stacked CP antenna elements is designed, fabricated and measured. Both the simulated and measured results indicate that the performances of the antenna element are further enhanced when the SR network is used. The antenna array exhibits the VSWR less than 1.8 dB from 4 GHz to 7 GHz and the 3 dB axial ratio (AR from 4.4 GHz to 6.8 GHz. Also, high peak gain of 13.7 dBic is obtained. Besides, the normalized radiation patterns at the operating frequencies are symmetrical and the side lobe levels are low at φ=0º and φ=90º.

  3. Wideband Dual-Polarization Patch Antenna Array With Parallel Strip Line Balun Feeding

    DEFF Research Database (Denmark)

    Zhang, Jin; Lin, Xianqi; Nie, Liying

    2016-01-01

    A wideband dual-polarization patch antenna array is proposed in this letter. The array is fed by a parallel strip line balun, which is adopted to generate 180° phase shift in a wide frequency range. In addition, this balun has simple structure, very small phase shift error, and good ports isolati...... is higher than 30 dB. The simulation and measurement turns out to be similar. This antenna array can be used in TD-LTE base stations, and the design methods are also useful to other wideband microstrip antennas....

  4. A Design Of Feeding Network For A Dual-Linear Polarization, Stacked, Probe-Fed Microstrip Patch Antenna Array

    DEFF Research Database (Denmark)

    Jaworski, G.; Krozer, Viktor

    2004-01-01

    Components of multilayer feed network are presented for application in broad-band dual-linear polarized stacked C-band antenna. Measurement results of wide band matching circuits and different types of power divider networks constituting parts of BFN demonstrate wideband operation. Suitable...

  5. Performance of a Highly Sensitive, 19-element, Dual-polarization, Cryogenic L-band Phased-array Feed on the Green Bank Telescope

    Science.gov (United States)

    Roshi, D. Anish; Shillue, W.; Simon, B.; Warnick, K. F.; Jeffs, B.; Pisano, D. J.; Prestage, R.; White, S.; Fisher, J. R.; Morgan, M.; Black, R.; Burnett, M.; Diao, J.; Ruzindana, M.; van Tonder, V.; Hawkins, L.; Marganian, P.; Chamberlin, T.; Ray, J.; Pingel, N. M.; Rajwade, K.; Lorimer, D. R.; Rane, A.; Castro, J.; Groves, W.; Jensen, L.; Nelson, J. D.; Boyd, T.; Beasley, A. J.

    2018-05-01

    A new 1.4 GHz, 19-element, dual-polarization, cryogenic phased-array feed (PAF) radio astronomy receiver has been developed for the Robert C. Byrd Green Bank Telescope (GBT) as part of the Focal L-band Array for the GBT (FLAG) project. Commissioning observations of calibrator radio sources show that this receiver has the lowest reported beam-formed system temperature (T sys) normalized by aperture efficiency (η) of any phased-array receiver to date. The measured T sys/η is 25.4 ± 2.5 K near 1350 MHz for the boresight beam, which is comparable to the performance of the current 1.4 GHz cryogenic single-feed receiver on the GBT. The degradation in T sys/η at ∼4‧ (required for Nyquist sampling) and ∼8‧ offsets from the boresight is, respectively, ∼1% and ∼20% of the boresight value. The survey speed of the PAF with seven formed beams is larger by a factor between 2.1 and 7 compared to a single-beam system, depending on the observing application. The measured performance, both in frequency and offset from the boresight, qualitatively agrees with predictions from a rigorous electromagnetic model of the PAF. The astronomical utility of the receiver is demonstrated by observations of the pulsar B0329+54 and an extended H II region, the Rosette Nebula. The enhanced survey speed with the new PAF receiver will enable the GBT to carry out exciting new science, such as more efficient observations of diffuse, extended neutral hydrogen emission from galactic inflows and searches for fast radio bursts.

  6. A Si nanocube array polarizer

    Science.gov (United States)

    Chen, Linghua; Jiang, Yingjie; Xing, Li; Yao, Jun

    2017-10-01

    We have proposed a full dielectric (silicon) nanocube array polarizer based on a silicon dioxide substrate. Each polarization unit column includes a plurality of equal spaced polarization units. By optimizing the length, the width, the height of the polarization units and the center distance of adjacent polarization unit (x direction and y direction), an extinction ratio (ER) of higher than 25dB was obtained theoretically when the incident light wavelength is 1550nm. while for applications of most polarization optical elements, ER above 10dB is enough. With this condition, the polarizer we designed can work in a wide wavelength range from 1509.31nm to 1611.51nm. Compared with the previous polarizer, we have introduced a polarizer which is a full dielectric device, which solves the problems of low efficiency caused by Ohmic loss and weak coupling. Furthermore, compared with the existing optical polarizers, our polarizer has the advantages of thin thickness, small size, light weight, and low processing difficulty, which is in line with the future development trend of optical elements.

  7. Diagnostics of the BIOMASS feed array prototype

    DEFF Research Database (Denmark)

    Cappellin, Cecilia; Pivnenko, Sergey; Pontoppidan, Kennie Nybo

    2013-01-01

    The 3D reconstruction algorithm is applied to the prototype feed array of the BIOMASS synthetic aperture radar, recently measured at the DTU-ESA Spherical Near-Field Antenna Test Facility in Denmark. Careful analysis of the measured feed array data has shown that the test support structure...

  8. Dual-band dual-polarized array for WLAN applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-01-01

    Full Text Available dual-band dual-polarized (DBDP) antenna design for WLAN applications. The antenna is in the form of an array consisting of four double-dipole radiators. The basic radiating element consists of a rhombus shaped dipole above a planar ground plane... the ground planes and the respective feedlines. Substrate cuts and difierent heights for the horizontal feedlines were necessary to achieve the latter. The 2nd conflguration (for vertical polarization) has a slightly difierent feeding network layout...

  9. Polarization Characterization of a Multi-Moded Feed Structure

    Data.gov (United States)

    National Aeronautics and Space Administration — The Polarization Characterization of a Multi-Moded Feed Structure projects characterize the polarization response of a multi-moded feed horn as an innovative...

  10. PHASED ARRAY FEED CALIBRATION, BEAMFORMING, AND IMAGING

    International Nuclear Information System (INIS)

    Landon, Jonathan; Elmer, Michael; Waldron, Jacob; Jones, David; Stemmons, Alan; Jeffs, Brian D.; Warnick, Karl F.; Richard Fisher, J.; Norrod, Roger D.

    2010-01-01

    Phased array feeds (PAFs) for reflector antennas offer the potential for increased reflector field of view and faster survey speeds. To address some of the development challenges that remain for scientifically useful PAFs, including calibration and beamforming algorithms, sensitivity optimization, and demonstration of wide field of view imaging, we report experimental results from a 19 element room temperature L-band PAF mounted on the Green Bank 20 Meter Telescope. Formed beams achieved an aperture efficiency of 69% and a system noise temperature of 66 K. Radio camera images of several sky regions are presented. We investigate the noise performance and sensitivity of the system as a function of elevation angle with statistically optimal beamforming and demonstrate cancelation of radio frequency interference sources with adaptive spatial filtering.

  11. Dual-polarized feed antenna apparatus and method of use

    Science.gov (United States)

    Sarehraz, Mohammed (Inventor); Buckle, Kenneth A. (Inventor); Stefanakos, Elias (Inventor); Weller, Thomas (Inventor); Goswami, D. Yogi (Inventor)

    2009-01-01

    An antenna apparatus and method for the interception of randomly polarized electromagnetic waves utilizing a dual polarized antenna which is excited through a cross-slot aperture using two well-isolated orthogonal feeds.

  12. Detailed Diagnostics of the BIOMASS Feed Array Prototype

    DEFF Research Database (Denmark)

    Cappellin, C.; Pivnenko, Sergey; Pontoppidan, K.

    2013-01-01

    of the array had a significant influence on the measured feed pattern. The 3D reconstruction and further post-processing is therefore applied both to the feed array measured data, and a set of simulated data generated by the GRASP software which replicate the series of measurements. The results...

  13. 5G antenna array with wide-angle beam steering and dual linear polarizations

    KAUST Repository

    Klionovski, Kirill; Shamim, Atif; Sharawi, Mohammad Said

    2017-01-01

    In this paper, we present the design of a switched-beam antenna array at millimeter-wave frequencies for future 5G applications. The proposed antenna array is based on wideband patch antenna elements and a Butler matrix feed network. The patch antenna has a broad radiation pattern for wide-angle beam steering and allows the simultaneous operation with two orthogonal linear polarizations. A combination of two separated Butler matrices provides independent beam steering for both polarizations in the wide operating band. The antenna array has a simple multilayer construction, and it is made on a low-cost Rogers laminate.

  14. 5G antenna array with wide-angle beam steering and dual linear polarizations

    KAUST Repository

    Klionovski, Kirill

    2017-10-25

    In this paper, we present the design of a switched-beam antenna array at millimeter-wave frequencies for future 5G applications. The proposed antenna array is based on wideband patch antenna elements and a Butler matrix feed network. The patch antenna has a broad radiation pattern for wide-angle beam steering and allows the simultaneous operation with two orthogonal linear polarizations. A combination of two separated Butler matrices provides independent beam steering for both polarizations in the wide operating band. The antenna array has a simple multilayer construction, and it is made on a low-cost Rogers laminate.

  15. Circularly Polarized Antenna Array Fed by Air-Bridge Free CPW-Slotline Network

    Directory of Open Access Journals (Sweden)

    Yilin Liu

    2017-01-01

    Full Text Available A novel design of 1×2 and 2×2 circularly polarized (CP microstrip patch antenna arrays is presented in this paper. The two CP antenna arrays are fed by sequentially rotated coplanar waveguide (CPW to slotline networks and are processed on 1 mm thick single-layer FR4 substrates. Both of the two arrays are low-profile and lightweight. An air-bridge free CPW-slotline power splitter is appropriately designed to form the feeding networks and realize the two CP antenna arrays. The mechanism of circular polarization in this design is explained. The simulated and measured impedance bandwidths as well as the 3 dB axial ratio bandwidths and the radiation patterns of the two proposed antenna arrays are presented. This proposed design can be easily extended to form a larger plane array with good performance owing to its simple structure.

  16. Polarization measurements made on LFRA and OASIS emitter arrays

    Science.gov (United States)

    Geske, Jon; Sparkman, Kevin; Oleson, Jim; Laveigne, Joe; Sieglinger, Breck; Marlow, Steve; Lowry, Heard; Burns, James

    2008-04-01

    Polarization is increasingly being considered as a method of discrimination in passive sensing applications. In this paper the degree of polarization of the thermal emission from the emitter arrays of two new Santa Barbara Infrared (SBIR) micro-bolometer resistor array scene projectors was characterized at ambient temperature and at 77 K. The emitter arrays characterized were from the Large Format Resistive Array (LFRA) and the Optimized Arrays for Space-Background Infrared Simulation (OASIS) scene projectors. This paper reports the results of this testing.

  17. A Microfabricated 8-40 GHz Dual-Polarized Reflector Feed

    Science.gov (United States)

    Vanhille, Kenneth; Durham, Tim; Stacy, William; Karasiewicz, David; Caba, Aaron; Trent, Christopher; Lambert, Kevin; Miranda, Felix

    2014-01-01

    Planar antennas based on tightly coupled dipole arrays (also known as a current sheet antenna or CSA) are amenable for use as electronically scanned phased arrays. They are capable of performance nearing a decade of bandwidth. These antennas have been demonstrated in many implementations at frequencies below 18 GHz. This paper describes the implementation using a relatively new multi-layer microfabrication process resulting in a small, 6x6 element, dual-linear polarized array with beamformer that operates from 8 to 40 GHz. The beamformer includes baluns that feed the dual-polarized differential antenna elements and reactive splitter networks that also cover the full frequency range of operation. This antenna array serves as a reflector feed for a multi-band instrument designed to measure snow water equivalent (SWE) from airborne platforms. The instrument has both radar and radiome try capability at multiple frequencies. Scattering-parameter and time-domain measurements have been used to characterize the array feed. Radiation patterns of the antenna have been measured and are compared to simulation. To the best of the authors' knowledge, this work represents the most integrated multi-octave millimeter-wave antenna feed fabricated to date.

  18. A Low VSWR and High Efficiency Waveguide Feed Antenna Array

    Directory of Open Access Journals (Sweden)

    Zhao Xiao-Fang

    2018-01-01

    Full Text Available A low VSWR and high efficiency antenna array operating in the Ku band for satellite communications is presented in this paper. To achieve high radiation efficiency and broad enough bandwidth, all-metal radiation elements and full-corporate waveguide feeding network are employed. As the general milling method is used in the multilayer antenna array fabrication, the E-plane waveguide feeding network is adopted here to suppress the wave leakage caused by the imperfect connectivity between adjacent layers. A 4 × 8 elements array prototype was fabricated and tested for verification. The measured results of proposed antenna array show bandwidth of 6.9% (13.9–14.8 GHz for VSWR < 1.5. Furthermore, antenna gain and efficiency of higher than 22.2 dBi and 80% are also exhibited, respectively.

  19. DUAL POLARIZATION ANTENNA ARRAY WITH VERY LOW CROSS POLARIZATION AND LOW SIDE LOBES

    DEFF Research Database (Denmark)

    1997-01-01

    The present invention relates to an antenna array adapted to radiate or receive electromagnetic waves of one or two polarizations with very low cross polarization and low side lobes. An antenna array comprising many antenna elements, e.g. more than ten antenna elements, is provided in which...... formation of grating lobes are inhibited in selected directions of the radiation and cross polarization within the main lobe is suppressed at least 30 dB below the main lobe peak value. According to a preferred embodiment of the invention, the antenna elements of the antenna array comprise probe-fed patches...

  20. MIMO Communication Using Single Feed Antenna Arrays

    DEFF Research Database (Denmark)

    Alrabadi, Osama

    Multi-input-multi-output (MIMO) communication has emerged as a promis- ing technology for meeting the increasing demand on higher data rates. The technology exploits the spatial resource dimension by sending the datas- treams to different locations in the multi element array (MEA) domain while...... conventionally to a single antenna element while mod- ulating the other datastreams in the analogue RF domain, using simple switched antenna systems (SAS) or sophisticated reactance-assisted antenna systems. The use of a SAS is found simple to implement, but can hardly handle high order signal formats...

  1. Polar exponential sensor arrays unify iconic and Hough space representation

    Science.gov (United States)

    Weiman, Carl F. R.

    1990-01-01

    The log-polar coordinate system, inherent in both polar exponential sensor arrays and log-polar remapped video imagery, is identical to the coordinate system of its corresponding Hough transform parameter space. The resulting unification of iconic and Hough domains simplifies computation for line recognition and eliminates the slope quantization problems inherent in the classical Cartesian Hough transform. The geometric organization of the algorithm is more amenable to massively parallel architectures than that of the Cartesian version. The neural architecture of the human visual cortex meets the geometric requirements to execute 'in-place' log-Hough algorithms of the kind described here.

  2. Cosmology from CMB Polarization with POLARBEAR and the Simons Array

    Science.gov (United States)

    Barron, Darcy; POLARBEAR Collaboration

    2018-01-01

    POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. The science goals of the POLARBEAR project are to do a deep search for CMB B-mode polarization created by inflationary gravitational waves, as well as characterize the CMB B-mode signal from gravitational lensing. POLARBEAR-1 started observations in 2012, and the POLARBEAR team has published a series of results from its first season of observations, including the first measurement of a non-zero B-mode polarization angular power spectrum, measured at sub-degree scales where the dominant signal is gravitational lensing of the CMB. Recently, we released an improved measurement of the B-mode polarization power spectrum, improving our band-power uncertainties by a factor of two, by adding new data from our second observing season and re-analyzing the combined data set.To further improve on these measurements, POLARBEAR is expanding to include an additional two telescopes with multi-chroic receivers observing at 95, 150, 220, and 270 GHz, known as the Simons Array. With high sensitivity and large sky coverage, the Simons Array will create a detailed survey of B-mode polarization, and its spectral information will be used to extract the CMB signal from astrophysical foregrounds. We will present the latest POLARBEAR results, as well as the status of development of the Simons Array and its expected capabilities.

  3. Spatiotemporal polarization modulation microscopy with a microretarder array

    Science.gov (United States)

    Ding, Changqin; Ulcickas, James R. W.; Simpson, Garth J.

    2018-02-01

    A patterned microretarder array positioned in the rear conjugate plane of a microscope enables rapid polarizationdependent nonlinear optical microscopy. The pattern introduced to the array results in periodic modulation of the polarization-state of the incident light as a function of position within the field of view with no moving parts or active control. Introduction of a single stationary optical element and a fixed polarizer into the beam of a nonlinear optical microscope enabled nonlinear optical tensor recovery, which informs on local structure and orientation. Excellent agreement was observed between the measured and predicted second harmonic generation (SHG) of z-cut quartz, selected as a test system with well-established nonlinear optical properties. Subsequent studies of spatially varying samples further support the general applicability of this relatively simple strategy for detailed polarization analysis in both conventional and nonlinear optical imaging of structurally diverse samples.

  4. Ultra-Wideband, Dual-Polarized, Beam-Steering P-Band Array Antenna

    Science.gov (United States)

    duToit, Cornelis

    2014-01-01

    A dual-polarized, wide-bandwidth (200 MHz for one polarization, 100 MHz for the orthogonal polarization) antenna array at P-band was designed to be driven by NASA's EcoSAR digital beam former. EcoSAR requires two wide P-band antenna arrays mounted on the wings of an aircraft, each capable of steering its main beam up to 35deg off-boresight, allowing the twin radar beams to be steered at angles to the flight path. The science requirements are mainly for dual-polarization capability and a wide bandwidth of operation of up to 200 MHz if possible, but at least 100 MHz with high polarization port isolation and low cross-polarization. The novel design geometry can be scaled with minor modifications up to about four times higher or down to about half the current design frequencies for any application requiring a dual-polarized, wide-bandwidth steerable antenna array. EcoSAR is an airborne interferometric P-band synthetic aperture radar (SAR) research application for studying two- and three-dimensional fine-scale measurements of terrestrial ecosystem structure and biomass, which will ultimately aid in the broader study of the carbon cycle and climate change. The two 2×8 element Pband antenna arrays required by the system will be separated by a baseline of about 25 m, allowing for interferometry measurements. The wide 100-to- 200-MHz bandwidth dual-polarized beams employed will allow the determination of the amount of biomass and even tree height on the ground. To reduce the size of the patches along the boresight dimension in order to fit them into the available space, two techniques were employed. One technique is to add slots along the edges of each patch where the main electric currents are expected to flow, and the other technique is to bend the central part of the patch away from the ground plane. The latter also facilitates higher mechanical rigidity. The high port isolation of more than 40 dB was achieved by employing a highly symmetrical feed mechanism for each

  5. Apertif: A new phased-array feed for WSRT

    Science.gov (United States)

    Adams, Elizabeth; Adebahr, Björn; de Blok, Willem J. G.; Hess, Kelley M.; Lucero, Danielle M.; Maccagni, Filippo; Morganti, Raffaella; Oosterloo, Tom A.; Ponomareva, Anastasia; Staveley-Smith, Lister; van der Hulst, J. M.; Verheijen, Marc A. W.; Verstappen, Joris

    2018-01-01

    Apertif is a phased-array feed for the Westerbork Synthesis Radio Telescope (WSRT), increasing the field of view of the telescope by a factor of twenty-five to 6.8 square degrees. In 2018, three legacy surveys will commence: a shallow imaging survey, a medium-deep imaging survey, and a pulsars and fast transients survey. The imaging surveys will be done in full polarization over the frequency range 1130-1430 MHz, which corresponds to redshifts of z=0-0.256 for neutral hydrogen (HI). The spectral resolution is 12.2 kHz, or an HI velocity resolution of 2.6 km/s at z=0 and 3.2 km/s at z=0.256. The full resolution images will have a beam size of 15"x15"/sin(declination), and tapered data products (i.e., 30" resolution images) will also be available. The footprints of the imaging surveys are chosen to maximize coverage of multi-wavelength datasets, including the Herschel Atlas North Galactic Pole field, HetDex region, plus coordination with MaNGA and planned WEAVE follow-up. The survey footprints were also chosen to probe different regions of interest, including the CVn region, Coma cluster, and Perseus-Pisces supercluster. The key science cases for the imaging surveys include understanding how galaxy properties depend on environment, the role of interactions and gas accretion and removal, understanding the smallest gas-rich galaxies, connecting cold gas to AGN, understanding the history of star formation and AGN activity in the faint radio continuum population, and studying magnetic fields in galaxies and large-scale structure. After a proprietary period, the survey data products will be publicly available through the Apertif Long Term Archive (ALTA). Up-to-date information on Apertif and the planned surveys can be found at www.apertif.nl.Commissioning of the Apertif instrument is underway. Here we will present results from the imaging commissioning, highlighting the capabilities of the instrument as related to the key science cases of the imaging surveys.

  6. Dual-Polarized Planar Phased Array Analysis for Meteorological Applications

    Directory of Open Access Journals (Sweden)

    Chen Pang

    2015-01-01

    Full Text Available This paper presents a theoretical analysis for the accuracy requirements of the planar polarimetric phased array radar (PPPAR in meteorological applications. Among many factors that contribute to the polarimetric biases, four factors are considered and analyzed in this study, namely, the polarization distortion due to the intrinsic limitation of a dual-polarized antenna element, the antenna pattern measurement error, the entire array patterns, and the imperfect horizontal and vertical channels. Two operation modes, the alternately transmitting and simultaneously receiving (ATSR mode and the simultaneously transmitting and simultaneously receiving (STSR mode, are discussed. For each mode, the polarimetric biases are formulated. As the STSR mode with orthogonal waveforms is similar to the ATSR mode, the analysis is mainly focused on the ATSR mode and the impacts of the bias sources on the measurement of polarimetric variables are investigated through Monte Carlo simulations. Some insights of the accuracy requirements are obtained and summarized.

  7. Parallel and series FED microstrip array with high efficiency and low cross polarization

    Science.gov (United States)

    Huang, John (Inventor)

    1995-01-01

    A microstrip array antenna for vertically polarized fan beam (approximately 2 deg x 50 deg) for C-band SAR applications with a physical area of 1.7 m by 0.17 m comprises two rows of patch elements and employs a parallel feed to left- and right-half sections of the rows. Each section is divided into two segments that are fed in parallel with the elements in each segment fed in series through matched transmission lines for high efficiency. The inboard section has half the number of patch elements of the outboard section, and the outboard sections, which have tapered distribution with identical transmission line sections, terminated with half wavelength long open-circuit stubs so that the remaining energy is reflected and radiated in phase. The elements of the two inboard segments of the two left- and right-half sections are provided with tapered transmission lines from element to element for uniform power distribution over the central third of the entire array antenna. The two rows of array elements are excited at opposite patch feed locations with opposite (180 deg difference) phases for reduced cross-polarization.

  8. Dual polarized receiving steering antenna array for measurement of ultrawideband pulse polarization structure

    Energy Technology Data Exchange (ETDEWEB)

    Balzovsky, E. V.; Buyanov, Yu. I.; Koshelev, V. I., E-mail: koshelev@lhfe.hcei.tsc.ru; Nekrasov, E. S. [Institute of High Current Electronics SB RAS, IHCE SB RAS, Tomsk 634055 (Russian Federation)

    2016-03-15

    To measure simultaneously two orthogonal components of the electromagnetic field of nano- and subnano-second duration, an antenna array has been developed. The antenna elements of the array are the crossed dipoles of dimension 5 × 5 cm. The arms of the dipoles are connected to the active four-pole devices to compensate the frequency response variations of a short dipole in the frequency band ranging from 0.4 to 4 GHz. The dipoles have superimposed phase centers allowing measuring the polarization structure of the field in different directions. The developed antenna array is the linear one containing four elements. The pattern maximum position is controlled by means of the switched ultrawideband true time delay lines. Discrete steering in seven directions in the range from −40° to +40° has been realized. The error at setting the pattern maximum position is less than 4°. The isolation of the polarization exceeds 29 dB in the direction orthogonal to the array axis and in the whole steering range it exceeds 23 dB. Measurement results of the polarization structure of radiated and scattered pulses with different polarization are presented as well.

  9. Copper nanorod array assisted silicon waveguide polarization beam splitter.

    Science.gov (United States)

    Kim, Sangsik; Qi, Minghao

    2014-04-21

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.

  10. Ku Band Phased Array Feed Development for Surface Water Ocean Topography Mission

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to design components essential to the development of phased arrays and phased array feeds for use in remote sensing. Specifically the...

  11. Chip-based microtrap arrays for cold polar molecules

    Science.gov (United States)

    Hou, Shunyong; Wei, Bin; Deng, Lianzhong; Yin, Jianping

    2017-12-01

    Compared to the atomic chip, which has been a powerful platform to perform an astonishing range of applications from rapid Bose-Einstein condensate (BEC) production to the atomic clock, the molecular chip is only in its infant stages. Recently a one-dimensional electric lattice was demonstrated to trap polar molecules on a chip. This excellent work opens up the way to building a molecular chip laboratory. Here we propose a two-dimensional (2D) electric lattice on a chip with concise and robust structure, which is formed by arrays of squared gold wires. Arrays of microtraps that originate in the microsize electrodes offer a steep gradient and thus allow for confining both light and heavy polar molecules. Theoretical analysis and numerical calculations are performed using two types of sample molecules, N D3 and SrF, to justify the possibility of our proposal. The height of the minima of the potential wells is about 10 μm above the surface of the chip and can be easily adjusted in a wide range by changing the voltages applied on the electrodes. These microtraps offer intriguing perspectives for investigating cold molecules in periodic potentials, such as quantum computing science, low-dimensional physics, and some other possible applications amenable to magnetic or optical lattice. The 2D adjustable electric lattice is expected to act as a building block for a future gas-phase molecular chip laboratory.

  12. Enhanced polarization of (11–22) semi-polar InGaN nanorod array structure

    Energy Technology Data Exchange (ETDEWEB)

    Athanasiou, M.; Smith, R. M.; Hou, Y.; Zhang, Y.; Gong, Y.; Wang, T., E-mail: t.wang@sheffield.ac.uk [Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2015-10-05

    By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11–22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal (PhC) structure. Such a PhC structure demonstrates not only significantly increased emission intensity, but also an enhanced polarization ratio of the emission. This is due to an effective inhibition of the emission in slab modes and then redistribution to the vertical direction, thus minimizing the light scattering processes that lead to randomizing of the optical polarization. The PhC structure is designed based on a standard finite-difference-time-domain simulation, and then optically confirmed by detailed time-resolved photoluminescence measurements. The results presented pave the way for the fabrication of semipolar InGaN/GaN based emitters with both high efficiency and highly polarized emission.

  13. Enhanced polarization of (11–22) semi-polar InGaN nanorod array structure

    International Nuclear Information System (INIS)

    Athanasiou, M.; Smith, R. M.; Hou, Y.; Zhang, Y.; Gong, Y.; Wang, T.

    2015-01-01

    By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11–22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal (PhC) structure. Such a PhC structure demonstrates not only significantly increased emission intensity, but also an enhanced polarization ratio of the emission. This is due to an effective inhibition of the emission in slab modes and then redistribution to the vertical direction, thus minimizing the light scattering processes that lead to randomizing of the optical polarization. The PhC structure is designed based on a standard finite-difference-time-domain simulation, and then optically confirmed by detailed time-resolved photoluminescence measurements. The results presented pave the way for the fabrication of semipolar InGaN/GaN based emitters with both high efficiency and highly polarized emission

  14. Polarization Smoothing Generalized MUSIC Algorithm with Polarization Sensitive Array for Low Angle Estimation.

    Science.gov (United States)

    Tan, Jun; Nie, Zaiping

    2018-05-12

    Direction of Arrival (DOA) estimation of low-altitude targets is difficult due to the multipath coherent interference from the ground reflection image of the targets, especially for very high frequency (VHF) radars, which have antennae that are severely restricted in terms of aperture and height. The polarization smoothing generalized multiple signal classification (MUSIC) algorithm, which combines polarization smoothing and generalized MUSIC algorithm for polarization sensitive arrays (PSAs), was proposed to solve this problem in this paper. Firstly, the polarization smoothing pre-processing was exploited to eliminate the coherence between the direct and the specular signals. Secondly, we constructed the generalized MUSIC algorithm for low angle estimation. Finally, based on the geometry information of the symmetry multipath model, the proposed algorithm was introduced to convert the two-dimensional searching into one-dimensional searching, thus reducing the computational burden. Numerical results were provided to verify the effectiveness of the proposed method, showing that the proposed algorithm has significantly improved angle estimation performance in the low-angle area compared with the available methods, especially when the grazing angle is near zero.

  15. Cirlularly Polarized Proximity- Fed Microstrip Array Antenna for LAPAN TUBSAT Micro Satellite System

    Directory of Open Access Journals (Sweden)

    Endra Wijaya

    2013-11-01

    Full Text Available The design microstrip of array antenna circular polarization characteristic developed for support LAPAN TUBSAT micro satellite system. The antenna on the micro satellite systems transmit data to ground stations operating at S band frequencies.The antenna is designed for impedance matching at frequencies of 2:25 GHz.The four elements of the square patch antenna array composed using linear methods, where the design of the transmission lines used by federal corporate structure model network consisting of three elements of the quarter wave transformer of a power divider. The feeding techniques for antenna designed using proximity coupling method, which for the type of substrate material used is similar. Circularly polarized antenna characteristics are influenced by the truncated corner pieces on the patch. To design the overall antenna used simulated method of moments in microwave office software applications. The results of measurements and simulations obtained antenna parameters, such as: bandwidth of return loss under 10 dB is 200 MHz (shifted 35%, bandwidth of axial ratio under 3dB is 1.7% and maximum gain directivity is 9 dB. Overall results obtained antenna parameters to meet the specifications of LAPAN TUBSAT micro satellite system.

  16. Modulation of electromagnetic fields by a depolarizer of random polarizer array

    DEFF Research Database (Denmark)

    Ma, Ning; Hanson, Steen Grüner; Wang, Wei

    2016-01-01

    The statistical properties of the electric fields with random changes of the polarization state in space generated by a depolarizer are investigated on the basis of the coherence matrix. The depolarizer is a polarizer array composed of a multitude of contiguous square cells of polarizers with ran......The statistical properties of the electric fields with random changes of the polarization state in space generated by a depolarizer are investigated on the basis of the coherence matrix. The depolarizer is a polarizer array composed of a multitude of contiguous square cells of polarizers...... with randomly distributed polarization angles, where the incident fields experience a random polarization modulation after passing through the depolarizer. The propagation of the modulated electric fields through any quadratic optical system is examined within the framework of the complex ABCD matrix to show...

  17. Multiple Interference Cancellation Performance for GPS Receivers with Dual-Polarized Antenna Arrays

    Directory of Open Access Journals (Sweden)

    Moeness G. Amin

    2008-11-01

    Full Text Available This paper examines the interference cancellation performance in global positioning system (GPS receivers equipped with dual-polarized antenna arrays. In dense jamming environment, different types of interferers can be mitigated by the dual-polarized antennas, either acting individually or in conjunction with other receiver antennas. We apply minimum variance distorntionless response (MVDR method to a uniform circular dual-polarized antenna array. The MVDR beamformer is constructed for each satellite. Analysis of the eigenstructures of the covariance matrix and the corresponding weight vector polarization characteristics are provided. Depending on the number of jammers and jammer polarizations, the array chooses to expend its degrees of freedom to counter the jammer polarization or/and use phase coherence to form jammer spatial nulls. Results of interference cancellations demonstrate that applying multiple MVDR beamformers, each for one satellite, has a superior cancellation performance compared to using only one MVDR beamformer for all satellites in the field of view.

  18. A Design of Wide Band and Wide Beam Cavity-Backed Slot Antenna Array with Slant Polarization

    Directory of Open Access Journals (Sweden)

    Huiying Qi

    2016-01-01

    Full Text Available Design of antenna array under the limitation of restricted size is a challenging problem. Cavity-backed slot antenna is widely used because of its advantages of small size, wide band, and wide beam. In this paper, a design of wide band and wide beam cavity-backed slot antenna array with the slant polarization is proposed. To obtain wide band and wide beam with limited size, the inverted microstrip-fed cavity-backed slot antenna (IMF-CBSA is adopted as the element of 1 × 4 antenna array. The slant polarized antennas and their feeding networks are adopted because of their simple structures. The performance of the proposed antenna array is verified by the simulations and experiments. The measured VSWR < 2 bandwidth is 55% at the center frequency 21.8 GHz, and the gain is larger than 12.2 dB. Experimental results demonstrate that the proposed design achieves wide band and beam with the size of 68 mm × 56 mm × 14.5 mm.

  19. Radial microstrip slotline feed network for circular mobile communications array

    Science.gov (United States)

    Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

    1994-01-01

    In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

  20. Design of Small CRPA Arrays with Circular Microstrip Loops for Electromagnetically Coupled Feed

    Directory of Open Access Journals (Sweden)

    Jun Hur

    2018-04-01

    Full Text Available This paper proposes a design of small controlled reception pattern antenna (CRPA arrays using circular microstrip loops with frequencyinsensitive characteristics. The proposed array consists of seven identical upper and lower circular loops that are electromagnetically coupled, which results in a frequency-insensitive behavior. To demonstrate the feasibility of the proposed feeding mechanism, the proposed array is fabricated, and its antenna characteristics are measured in a full-anechoic chamber. The operating principle of the proposed feeding mechanism is then interpreted using an equivalent circuit model, and the effectiveness of the circular loop shape is demonstrated by calculating near electromagnetic fields in proximity to the radiator. The results confirm that the proposed feeding mechanism is suitable to have frequency-insensitive behavior and induces strong electric and magnetic field strengths for higher radiation gain in extremely small antenna arrays.

  1. X-ray polarimetry with the Polarization Spectroscopic Telescope Array (PolSTAR)

    DEFF Research Database (Denmark)

    Krawczynski, Henric S.; Stern, Daniel; Harrison, Fiona A.

    2016-01-01

    This paper describes the Polarization Spectroscopic Telescope Array (PolSTAR), a mission proposed to NASA's 2014 Small Explorer (SMEX) announcement of opportunity. PolSTAR measures the linear polarization of 3-50 keV (requirement; goal: 2.5-70 keV) X-rays probing the behavior of matter,radiation ...

  2. Mechanically Reconfigurable Single-Arm Spiral Antenna Array for Generation of Broadband Circularly Polarized Orbital Angular Momentum Vortex Waves.

    Science.gov (United States)

    Li, Long; Zhou, Xiaoxiao

    2018-03-23

    In this paper, a mechanically reconfigurable circular array with single-arm spiral antennas (SASAs) is designed, fabricated, and experimentally demonstrated to generate broadband circularly polarized orbital angular momentum (OAM) vortex waves in radio frequency domain. With the symmetrical and broadband properties of single-arm spiral antennas, the vortex waves with different OAM modes can be mechanically reconfigurable generated in a wide band from 3.4 GHz to 4.7 GHz. The prototype of the circular array is proposed, conducted, and fabricated to validate the theoretical analysis. The simulated and experimental results verify that different OAM modes can be effectively generated by rotating the spiral arms of single-arm spiral antennas with corresponding degrees, which greatly simplify the feeding network. The proposed method paves a reconfigurable way to generate multiple OAM vortex waves with spin angular momentum (SAM) in radio and microwave satellite communication applications.

  3. Reconfigurable Transmission Line for a Series-Fed Ku-Band Phased Array Using a Single Feed

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda. Felix, A.

    2013-01-01

    The paper presents a novel approach to realize a lowcost phased array using a simple feeding mechanism. Specifically, a single coplanar stripline (CPS) transmission line is used to feed the antenna array elements. By controlling the CPS's dielectric properties using a movable dielectric plunger, scanning is achieved. Due to its simplicity, single feed, and no phase shifters, this approach leads to a dramatic reduction in cost which does not scale for larger arrays.

  4. Dual-polarization, wideband microstrip antenna array for airborne C-band SAR

    DEFF Research Database (Denmark)

    Granholm, Johan; Skou, Niels

    2000-01-01

    The paper describes the development of a C-band, dual linear polarization wideband antenna array, for use in the next-generation of the Danish airborne polarimetric synthetic aperture radar (SAR) system. The array is made of probe-fed, stacked microstrip patches. The design and performance of the...... of the basic stacked patch element, operating from 4.9 GHz to 5.7 GHz, and a 2×2 element test array of these, are described.......The paper describes the development of a C-band, dual linear polarization wideband antenna array, for use in the next-generation of the Danish airborne polarimetric synthetic aperture radar (SAR) system. The array is made of probe-fed, stacked microstrip patches. The design and performance...

  5. Full-Stokes polarimetry with circularly polarized feeds. Sources with stable linear and circular polarization in the GHz regime

    Science.gov (United States)

    Myserlis, I.; Angelakis, E.; Kraus, A.; Liontas, C. A.; Marchili, N.; Aller, M. F.; Aller, H. D.; Karamanavis, V.; Fuhrmann, L.; Krichbaum, T. P.; Zensus, J. A.

    2018-01-01

    We present an analysis pipeline that enables the recovery of reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the effective treatment of the instrumental effects even before the computation of the Stokes parameters, contrary to conventionally used methods such as that based on the Müller matrix. For instance, instrumental linear polarization is corrected across the whole telescope beam and significant Stokes Q and U can be recovered even when the recorded signals are severely corrupted by instrumental effects. The accuracy we reach in terms of polarization degree is of the order of 0.1-0.2%. The polarization angles are determined with an accuracy of almost 1°. The presented methodology was applied to recover the linear and circular polarization of around 150 active galactic nuclei, which were monitored between July 2010 and April 2016 with the Effelsberg 100-m telescope at 4.85 GHz and 8.35 GHz with a median cadence of 1.2 months. The polarized emission of the Moon was used to calibrate the polarization angle measurements. Our analysis showed a small system-induced rotation of about 1° at both observing frequencies. Over the examined period, five sources have significant and stable linear polarization; three sources remain constantly linearly unpolarized; and a total of 11 sources have stable circular polarization degree mc, four of them with non-zero mc. We also identify eight sources that maintain a stable polarization angle. All this is provided to the community for future polarization observations reference. We finally show that our analysis method is conceptually different from those traditionally used and performs better than the Müller matrix method. Although it has been developed for a system equipped with circularly polarized feeds, it can easily be generalized to systems with linearly polarized feeds as well. The data used to create Fig. C.1 are only available at the CDS via anonymous ftp to http

  6. Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

    Science.gov (United States)

    Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

    1986-01-01

    A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

  7. Light polarization management via reflection from arrays of sub-wavelength metallic twisted bands

    Science.gov (United States)

    Nawrot, M.; Haberko, J.; Zinkiewicz, Ł.; Wasylczyk, P.

    2017-12-01

    With constant progress of nano- and microfabrication technologies, photolithography in particular, a number of sub-wavelength metallic structures have been demonstrated that can be used to manipulate light polarization. Numerical simulations of light propagation hint that helical twisted bands can have interesting polarization properties. We use three-dimensional two-photon photolithography (direct laser writing) to fabricate a few-micrometer-thick arrays of twisted bands and coat them uniformly with metal. We demonstrate that circular polarization can be generated from linear polarization upon reflection from such structures over a broad range of frequencies in the mid infrared.

  8. Circularly Polarized Planar Helix Phased Antenna Array for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Syrytsin, Igor A.; Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    In this paper, a planar helix mobile phased antenna array is proposed for 5th generation communication systems with operating frequency of 28GHz. The proposed array displays circular polarization in the endfire direction. Over 65 degrees of axial ratio beamwidth and 7GHz of axial ratio bandwidth...... has been achieved in the proposed design. The coverage performance of the proposed phased antenna array has also been studied by using the coverage efficiency metric. Coverage efficiency of 50 % at 5 dBi gain is achieved by the proposed phased mobile antenna array....

  9. A Small Ku-Band Polarization Tracking Active Phased Array for Mobile Satellite Communications

    Directory of Open Access Journals (Sweden)

    Wei Shi

    2013-01-01

    Full Text Available A compact polarization tracking active phased array for Ku-band mobile satellite signal reception is presented. In contrast with conventional mechanically tracking antennas, the approach presented here meets the requirements of beam tracking and polarization tracking simultaneously without any servo components. The two-layer stacked square patch fed by two probes is used as antenna element. The impedance bandwidth of 16% for the element covers the operating frequency range from 12.25 GHz to 12.75 GHz. In the presence of mutual coupling, the dimensional parameters for each element of the small 7 × 7 array are optimized during beam scanning and polarization tracking. The compact polarization tracking modules based on the low-temperature cofired ceramic (LTCC system-in-package (SiP technology are proposed. A small active phased array prototype with the size of 120 mm (length × 120 mm (width × 55 mm (height is developed. The measured polarization tracking patterns of the prototype are given. The polarization tracking beam can be steered in the elevation up to 50°. The gain of no less than 16.0 dBi and the aperture efficiency of more than 50% are obtained. The measured and simulated polarization tracking patterns agreed well.

  10. Prospects for quantum computing with an array of ultracold polar paramagnetic molecules.

    Science.gov (United States)

    Karra, Mallikarjun; Sharma, Ketan; Friedrich, Bretislav; Kais, Sabre; Herschbach, Dudley

    2016-03-07

    Arrays of trapped ultracold molecules represent a promising platform for implementing a universal quantum computer. DeMille [Phys. Rev. Lett. 88, 067901 (2002)] has detailed a prototype design based on Stark states of polar (1)Σ molecules as qubits. Herein, we consider an array of polar (2)Σ molecules which are, in addition, inherently paramagnetic and whose Hund's case (b) free-rotor pair-eigenstates are Bell states. We show that by subjecting the array to combinations of concurrent homogeneous and inhomogeneous electric and magnetic fields, the entanglement of the array's Stark and Zeeman states can be tuned and the qubit sites addressed. Two schemes for implementing an optically controlled CNOT gate are proposed and their feasibility discussed in the face of the broadening of spectral lines due to dipole-dipole coupling and the inhomogeneity of the electric and magnetic fields.

  11. Analysis of Circularly Polarized Hemispheroidal Dielectric Resonator Antenna Phased Arrays Using the Method of Auxiliary Sources

    DEFF Research Database (Denmark)

    Larsen, Niels Vesterdal; Breinbjerg, Olav

    2007-01-01

    The method of auxiliary sources is employed to model and analyze probe-fed hemispheroidal dielectric resonator antennas and arrays. Circularly polarized antenna elements of different designs are analyzed, and impedance bandwidths of up to 14.7% are achieved. Selected element designs are subsequen......The method of auxiliary sources is employed to model and analyze probe-fed hemispheroidal dielectric resonator antennas and arrays. Circularly polarized antenna elements of different designs are analyzed, and impedance bandwidths of up to 14.7% are achieved. Selected element designs...

  12. Characterization of RF-spittered self-polarized PZT thin films for sensors arrays

    Czech Academy of Sciences Publication Activity Database

    Suchaneck, G.; Lin, W. M.; Koehler, R.; Sandner, T.; Gerlach, G.; Krawietz, R.; Pompe, W.; Deineka, Alexander; Jastrabík, Lubomír

    2002-01-01

    Roč. 66, - (2002), s. 473-478 ISSN 0042-207X R&D Projects: GA MŠk LN00A015; GA ČR GA202/00/1425 Institutional research plan: CEZ:AV0Z1010914 Keywords : self-polarized PZT * polarization and refractive index profiles * IR sensor array Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.723, year: 2002

  13. Soldered Contact and Current Risetime Effects on Negative Polarity Wire Array Z-pinches

    International Nuclear Information System (INIS)

    Chalenski, D. A.; Kusse, B. R.; Greenly, J. B.; Blesener, I. C.; McBride, R. D.; Hammer, D. A.; Knapp, P. F.

    2009-01-01

    The Cornell University COBRA pulser is a nominal 1 MA machine, capable of driving up to 32 wire cylindrical Z-pinch arrays. COBRA can operate with variable current risetimes ranging from 100 ns to 200 ns (short and long pulse, respectively). Wires are typically strung with a ''press'' contact to the electrode hardware, where the wire is loosely pulled against the hardware and held there to establish electrical contact. The machine is normally negative, but a bolt-on convolute can be used to modify the current path and effectively produce positive polarity operation at the load.Previous research with single wires on a 1-5 kA pulser has shown that soldering the wire, thereby improving the wire/electrode contact, and operating in positive polarity can improve the energy deposition into the wire and enhance wire core expansion. Negative polarity showed no difference. Previous experiments on the negative polarity, 20 MA, 100 ns Z accelerator have shown that improving the contact improved the x-ray yield.Cornell data were collected on 16-wire Aluminum Z-pinch arrays in negative polarity. Experiments were conducted with both short and long current pulses with soldered and no-soldered wire/electrode contacts. The initiation, ablation, implosion and stagnation phases were compared for these four conditions. Time dependent x-ray signals were measured using diodes and diamond detectors. An inductive voltage monitor was used to infer minimum current radius achieved, as defined by a uniform shell of current moving radially inward, producing a time dependent inductance. Total energy data were collected with a metal-strip bolometer. Self-emission data were collected by an XUV 4-frame camera and an optical streak camera.In negative polarity and with short pulses, soldering appeared to produce a smaller radius pinch and decrease variations in the x-ray pulse shape. The bolometer, laser backlighter, 4-frame and streak cameras showed negligible differences in the initiation ablation

  14. A coherent polarimeter array for the Large Scale Polarization Explorer balloon experiment

    OpenAIRE

    Bersanelli, M.; Mennella, A.; Morgante, G.; Zannoni, M.; Addamo, G.; Baschirotto, A.; Battaglia, P.; Baù, A.; Cappellini, B.; Cavaliere, F.; Cuttaia, F.; Del Torto, F.; Donzelli, S.; Farooqui, Z.; Frailis, M.

    2012-01-01

    We discuss the design and expected performance of STRIP (STRatospheric Italian Polarimeter), an array of coherent receivers designed to fly on board the LSPE (Large Scale Polarization Explorer) balloon experiment. The STRIP focal plane array comprises 49 elements in Q band and 7 elements in W-band using cryogenic HEMT low noise amplifiers and high performance waveguide components. In operation, the array will be cooled to 20 K and placed in the focal plane of a $\\sim 0.6$ meter telescope prov...

  15. The use of the multiple-gradient array for geoelectrical resistivity and induced polarization imaging

    Science.gov (United States)

    Aizebeokhai, Ahzegbobor P.; Oyeyemi, Kehinde D.

    2014-12-01

    The use of most conventional electrode configurations in electrical resistivity survey is often time consuming and labour intensive, especially when using manual data acquisition systems. Often, data acquisition teams tend to reduce data density so as to speed up field operation thereby reducing the survey cost; but this could significantly degrade the quality and resolution of the inverse models. In the present work, the potential of using the multiple-gradient array, a non-conventional electrode configuration, for practical cost effective and rapid subsurface resistivity and induced polarization mapping was evaluated. The array was used to conduct 2D resistivity and time-domain induced polarization imaging along two traverses in a study site at Ota, southwestern Nigeria. The subsurface was characterised and the main aquifer delineated using the inverse resistivity and chargeability images obtained. The performance of the multiple-gradient array was evaluated by correlating the 2D resistivity and chargeability images with those of the conventional Wenner array as well as the result of some soundings conducted along the same traverses using Schlumberger array. The multiple-gradient array has been found to have the advantage of measurement logistics and improved image resolution over the Wenner array.

  16. High Isolation Dual-Polarized Patch Antenna with Hybrid Ring Feeding

    Directory of Open Access Journals (Sweden)

    Xian-Jing Lin

    2017-01-01

    Full Text Available This paper presents a hybrid ring feeding dual-polarized patch antenna with high isolation in a wide working band. The proposed antenna consists of a circular radiating patch printed on the upper horizontal substrate, two pairs of Γ shaped strips printed on two vertical substrates, and a hybrid ring feeding network printed on the lower two horizontal substrates. The proposed antenna adopts Γ shape strips coupled feeding structure to achieve a wide operating band. Furthermore, a hybrid ring feeding structure with high isolation in a wide bandwidth, which is firstly proposed, is applied as feeding network. When one port is excited, the feeding network can realize twice the power cancellation. Thus, high ports isolation characteristics can be obtained. A prototype of the proposed antenna is fabricated and measured. Measured results show that the 10 dB reflection coefficient bandwidths of the two ports are both about 38.7%, with port isolation higher than 40 dB through most of the band, and the cross-polarizations are below −24 dB.

  17. Polarized Uniform Linear Array System: Beam Radiation Pattern, Beamforming Diversity Order, and Channel Capacity

    Directory of Open Access Journals (Sweden)

    Xin Su

    2015-01-01

    Full Text Available There have been many studies regarding antenna polarization; however, there have been few publications on the analysis of the channel capacity for polarized antenna systems using the beamforming technique. According to Chung et al., the channel capacity is determined by the density of scatterers and the transmission power, which is obtained based on the assumption that scatterers are uniformly distributed on a 3D spherical scattering model. However, it contradicts the practical scenario, where scatterers may not be uniformly distributed under outdoor environment, and lacks the consideration of fading channel gain. In this study, we derive the channel capacity of polarized uniform linear array (PULA systems using the beamforming technique in a practical scattering environment. The results show that, for PULA systems, the channel capacity, which is boosted by beamforming diversity, can be determined using the channel gain, beam radiation pattern, and beamforming diversity order (BDO, where the BDO is dependent on the antenna characteristics and array configurations.

  18. A Multibeam Dual-Band Orthogonal Linearly Polarized Antenna Array for Satellite Communication on the Move

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2015-01-01

    Full Text Available The design and simulation of a 10 × 8 multibeam dual-band orthogonal linearly polarized antenna array operating at Ku-band are presented for transmit-receive applications. By using patches with different coupling methods as elements, both perpendicular polarization in 12.25–12.75 GHz band and horizontal polarization in 14.0–14.5 GHz band are realized in a shared antenna aperture. A microstrip Rotman lens is employed as the beamforming network with 7 input ports, which can generate a corresponding number of beams to cover −30°–30° with 5 dB beamwidth along one dimension. This type of multibeam orthogonal linearly polarized planar antenna is a good candidate for satellite communication (SatCom.

  19. Local polarization phenomena in In-doped CdTe x-ray detector arrays

    International Nuclear Information System (INIS)

    Sato, Toshiyuki; Sato, Kenji; Ishida, Shinichiro; Kiri, Motosada; Hirooka, Megumi; Yamada, Masayoshi; Kanamori, Hitoshi

    1995-01-01

    Local polarization phenomena have been studied in detector arrays with the detector element size of 500 microm x 500 microm, which are fabricated from high-resistivity In-doped CdTe crystals grown by the vertical Bridgman technique. It has been found for the first time that a polarization effect, which is characterized by a progressive decrease of the pulse counting rate with increasing photon fluence, strongly depends on the detector elements, that is, the portion of crystals used. The influence of several parameters, such as the applied electric field strength, time, and temperature, on this local polarization effect is also investigated. From the photoluminescence measurements of the inhomogeneity of In dopant, it is concluded that the local polarization effect observed here originates from a deep level associated with In dopant in CdTe crystals

  20. Simple and polarization-independent Dammann grating based on all-dielectric nanorod array

    Science.gov (United States)

    Yang, Sen; Li, Chuang; Liu, Tongming; Da, Haixia; Feng, Rui; Tang, Donghua; Sun, Fangkui; Ding, Weiqiang

    2017-09-01

    In this work, we comprehensively investigate a Dammann grating (DG) that can generate a 5 × 5 diffraction spot array with an extending angle of 18^\\circ × 18^\\circ around the fiber communication wavelength of 1550 {nm}. The DG is a simple metasurface structure composed of a silicon cuboid nanorod array on a silica substrate, and only two different sizes of nanorods with square cross-sections and uniform spatial orientations are used. These simple units and this configuration are favorable in practice, and the C4 symmetry cross section of the nanorods ensures the polarization-independent operation of the DG. The phase modulation of the nanorods is achieved by the guiding mode propagating in them rather than electric or magnetic Mie-type resonance, which makes the design of the cuboid nanorods easy and robust. More importantly, the two-dimensional nanorod array is generated from a one-dimensional array, which further decreases the design and fabrication complexity.

  1. Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

    Science.gov (United States)

    Rengarajan, Sembiam

    2012-01-01

    Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an

  2. Scattering Analysis of a Compact Dipole Array with Series and Parallel Feed Network including Mutual Coupling Effect

    Directory of Open Access Journals (Sweden)

    H. L. Sneha

    2013-01-01

    Full Text Available The current focus in defense arena is towards the stealth technology with an emphasis to control the radar cross-section (RCS. The scattering from the antennas mounted over the platform is of prime importance especially for a low-observable aerospace vehicle. This paper presents the analysis of the scattering cross section of a uniformly spaced linear dipole array. Two types of feed networks, that is, series and parallel feed networks, are considered. The total RCS of phased array with either kind of feed network is obtained by following the signal as it enters through the aperture and travels through the feed network. The RCS estimation of array is done including the mutual coupling effect between the dipole elements in three configurations, that is, side-by-side, collinear, and parallel-in-echelon. The results presented can be useful while designing a phased array with optimum performance towards low observability.

  3. An LTCC Based Compact SIW Antenna Array Feed Network for a Passive Imaging Radiometer

    KAUST Repository

    Abuzaid, Hattan

    2013-02-05

    Passive millimeter-wave (PMMW) imaging is a technique that allows the detection of inherent millimeter-wave radiation emitted by bodies. Since different bodies with varying properties emit unequal power intensities, a contrast can be established to detect their presence. The advantage of this imaging scheme over other techniques, such as optical and infrared imaging, is its ability to operate under all weather conditions. This is because the relatively long wavelengths of millimeter-waves, as compared to visible light, penetrate through clouds, fog, and sandstorms. The core of a PMMW camera is an antenna, which receives the electromagnetic radiation from a scene. Because PMMW systems require high gains to operate, large antenna arrays are typically employed. This mandatory increase of antenna elements is associated with a large feeding network. Therefore, PMMW cameras usually have a big profile. In this work, two enabling technologies, namely, Substrate integrated Waveguide (SIW) and Low Temperature Co-fired Ceramic (LTCC), are coupled with an innovative design to miniaturize the passive front-end. The two technologies synergize very well with the shielded characteristics of SIW and the high density multilayer integration of LTCC. The proposed design involves a novel multilayer power divider, which is incorporated in a folded feed network structure by moving between layers. The end result is an efficient feeding network, which footprint is least affected by an increase in array size. This is because the addition of more elements is accommodated by a vertical expansion rather than a lateral one. To characterize the feed network, an antenna array has been designed and integrated through efficient transitions.The complete structure has been simulated and fabricated. The results demonstrate an excellent performance, manifesting in a gain of 20 dBi and a bandwidth of more than 11.4% at 35 GHz. These values satisfy the general requirements of a PMMW system.

  4. Fabrication of antenna-coupled transition edge polarization-sensitive bolometer arrays

    International Nuclear Information System (INIS)

    Yun, Minhee; Bock, James; Leduc, Henry; Day, Peter; Kim, Moon J.

    2004-01-01

    We have fabricated antenna-coupled superconducting transition edge sensor (TES) arrays for far-infrared and millimeter-wave applications. The advantage of antenna coupling is that the large optical coupling structure required for far-infrared/millimeter wavelengths is not thermally active. The sensor can thus be as small as lithographic techniques permit. By eliminating large absorbers, this technology enables bolometers working at frequencies as low as 30 GHz, covering the entire spectral region of interest for future space-borne studies of cosmic microwave background polarization. We developed a focal plane architecture with dual-polarization sensitivity in a single spectral band, or single-polarization sensitivity in multiple spectral bands. We use TES layers consisting of Al/Ti/Au/Ti thin films and Nb electrical contacts on a low-stress Si 3 N 4 membrane

  5. Dual Circularly Polarized Omnidirectional Antenna with Slot Array on Coaxial Cylinder

    Directory of Open Access Journals (Sweden)

    Bin Zhou

    2015-01-01

    Full Text Available A dual circularly polarized (CP omnidirectional antenna based on slot array in coaxial cylinder structure is presented in this paper. It is constructed by perpendicular slot pairs around and along the axis of the coaxial cylinder to realize the omnidirectional CP property, and two ports are assigned in its two sides as left hand circularly polarized (LHCP port and right hand circularly polarized (RHCP port, respectively. The proposed antenna achieves a bandwidth of 16.4% ranging from 5.05 to 5.95 GHz with an isolation higher than 15 dB between the two CP ports, and the return loss (RL is higher than 10 dB within the bandwidth in both of the two ports. From the measured results, the average axial ratio (AR of the proposed antenna in omnidirectional plane is lower than 1.5 dB.

  6. A digital combining-weight estimation algorithm for broadband sources with the array feed compensation system

    Science.gov (United States)

    Vilnrotter, V. A.; Rodemich, E. R.

    1994-01-01

    An algorithm for estimating the optimum combining weights for the Ka-band (33.7-GHz) array feed compensation system was developed and analyzed. The input signal is assumed to be broadband radiation of thermal origin, generated by a distant radio source. Currently, seven video converters operating in conjunction with the real-time correlator are used to obtain these weight estimates. The algorithm described here requires only simple operations that can be implemented on a PC-based combining system, greatly reducing the amount of hardware. Therefore, system reliability and portability will be improved.

  7. Single-Layer, Dual-Port, Dual-Band, and Orthogonal-Circularly Polarized Microstrip Antenna Array with Low Frequency Ratio

    Directory of Open Access Journals (Sweden)

    Min Wang

    2018-01-01

    Full Text Available A single-layer, dual-port, dual-band, and dual circularly polarized (CP microstrip array is designed for satellite communication in this paper. The operating frequencies are 8.2 and 8.6 GHz with a very low ratio of 1.05. First, a rectangular patch element is fed through microstrip lines at two orthogonal edges to excite two orthogonal dominant modes of TM01 and TM10. The very low frequency ratio can be realized with high polarization isolations. Then, a 2-by-2 dual-band dual-CP subarray is constructed by two independent sets of sequentially rotated (SR feed structures. An 8-by-8 array is designed on the single-layer thin substrate. Finally, by utilizing one-to-four power dividers and semirigid coaxial cables, a 16-by-16 array is developed to achieve higher gain. Measured results show that the 16-by-16 array has 15 dB return loss (RL bandwidths of 4.81% and 6.75% and 3 dB axial ratio (AR bandwidths of 2.84% and 1.57% in the lower and the upper bands, respectively. Isolations of 18.6 dB and 19.4 dB and peak gains of 25.1 dBic and 25.6 dBic are obtained at 8.2 and 8.6 GHz, respectively.

  8. Anatomical Reconstruction and Functional Imaging Reveal an Ordered Array of Skylight Polarization Detectors in Drosophila.

    Science.gov (United States)

    Weir, Peter T; Henze, Miriam J; Bleul, Christiane; Baumann-Klausener, Franziska; Labhart, Thomas; Dickinson, Michael H

    2016-05-11

    Many insects exploit skylight polarization as a compass cue for orientation and navigation. In the fruit fly, Drosophila melanogaster, photoreceptors R7 and R8 in the dorsal rim area (DRA) of the compound eye are specialized to detect the electric vector (e-vector) of linearly polarized light. These photoreceptors are arranged in stacked pairs with identical fields of view and spectral sensitivities, but mutually orthogonal microvillar orientations. As in larger flies, we found that the microvillar orientation of the distal photoreceptor R7 changes in a fan-like fashion along the DRA. This anatomical arrangement suggests that the DRA constitutes a detector for skylight polarization, in which different e-vectors maximally excite different positions in the array. To test our hypothesis, we measured responses to polarized light of varying e-vector angles in the terminals of R7/8 cells using genetically encoded calcium indicators. Our data confirm a progression of preferred e-vector angles from anterior to posterior in the DRA, and a strict orthogonality between the e-vector preferences of paired R7/8 cells. We observed decreased activity in photoreceptors in response to flashes of light polarized orthogonally to their preferred e-vector angle, suggesting reciprocal inhibition between photoreceptors in the same medullar column, which may serve to increase polarization contrast. Together, our results indicate that the polarization-vision system relies on a spatial map of preferred e-vector angles at the earliest stage of sensory processing. The fly's visual system is an influential model system for studying neural computation, and much is known about its anatomy, physiology, and development. The circuits underlying motion processing have received the most attention, but researchers are increasingly investigating other functions, such as color perception and object recognition. In this work, we investigate the early neural processing of a somewhat exotic sense, called

  9. Dual-Polarization, Multi-Frequency Antenna Array for use with Hurricane Imaging Radiometer

    Science.gov (United States)

    Little, John

    2013-01-01

    Advancements in common aperture antenna technology were employed to utilize its proprietary genetic algorithmbased modeling tools in an effort to develop, build, and test a dual-polarization array for Hurricane Imaging Radiometer (HIRAD) applications. Final program results demonstrate the ability to achieve a lightweight, thin, higher-gain aperture that covers the desired spectral band. NASA employs various passive microwave and millimeter-wave instruments, such as spectral radiometers, for a range of remote sensing applications, from measurements of the Earth's surface and atmosphere, to cosmic background emission. These instruments such as the HIRAD, SFMR (Stepped Frequency Microwave Radiometer), and LRR (Lightweight Rainfall Radiometer), provide unique data accumulation capabilities for observing sea surface wind, temperature, and rainfall, and significantly enhance the understanding and predictability of hurricane intensity. These microwave instruments require extremely efficient wideband or multiband antennas in order to conserve space on the airborne platform. In addition, the thickness and weight of the antenna arrays is of paramount importance in reducing platform drag, permitting greater time on station. Current sensors are often heavy, single- polarization, or limited in frequency coverage. The ideal wideband antenna will have reduced size, weight, and profile (a conformal construct) without sacrificing optimum performance. The technology applied to this new HIRAD array will allow NASA, NOAA, and other users to gather information related to hurricanes and other tropical storms more cost effectively without sacrificing sensor performance or the aircraft time on station. The results of the initial analysis and numerical design indicated strong potential for an antenna array that would satisfy all of the design requirements for a replacement HIRAD array. Multiple common aperture antenna methodologies were employed to achieve exceptional gain over the entire

  10. A Tutorial on Optical Feeding of Millimeter-Wave Phased Array Antennas for Communication Applications

    Directory of Open Access Journals (Sweden)

    Ivan Aldaya

    2015-01-01

    Full Text Available Given the interference avoidance capacity, high gain, and dynamical reconfigurability, phased array antennas (PAAs have emerged as a key enabling technology for future broadband mobile applications. This is especially important at millimeter-wave (mm-wave frequencies, where the high power consumption and significant path loss impose serious range constraints. However, at mm-wave frequencies the phase and amplitude control of the feeding currents of the PAA elements is not a trivial issue because electrical beamforming requires bulky devices and exhibits relatively narrow bandwidth. In order to overcome these limitations, different optical beamforming architectures have been presented. In this paper we review the basic principles of phased arrays and identify the main challenges, that is, integration of high-speed photodetectors with antenna elements and the efficient optical control of both amplitude and phase of the feeding current. After presenting the most important solutions found in the literature, we analyze the impact of the different noise sources on the PAA performance, giving some guidelines for the design of optically fed PAAs.

  11. Three-dimensional imaging through turbid media based on polarization-difference liquid-crystal microlens array

    Science.gov (United States)

    Xin, Zhaowei; Wei, Dong; Li, Dapeng; Xie, Xingwang; Chen, Mingce; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

    2018-02-01

    In this paper, a polarization difference liquid-crystal microlens array (PD-LCMLA) for three dimensional imaging application through turbid media is fabricated and demonstrated. This device is composed of a twisted nematic liquidcrystal cell (TNLCC), a polarizer and a liquid-crystal microlens array. The polarizer is sandwiched between the TNLCC and LCMLA to help the polarization difference system achieving the orthogonal polarization raw images. The prototyped camera for polarization difference imaging has been constructed by integrating the PD-LCMLA with an image sensor. The orthogonally polarized light-field images are recorded by switching the working state of the TNLCC. Here, by using a special microstructure in conjunction with the polarization-difference algorithm, we demonstrate that the three-dimensional information in the scattering media can be retrieved from the polarization-difference imaging system with an electrically tunable PD-LCMLA. We further investigate the system's potential function based on the flexible microstructure. The microstructure provides a wide operation range in the manipulation of incident beams and also emerges multiple operation modes for imaging applications, such as conventional planar imaging, polarization imaging mode, and polarization-difference imaging mode. Since the PD-LCMLA demonstrates a very low power consumption, multiple imaging modes and simple manufacturing, this kind of device presents a potential to be used in many other optical and electro-optical systems.

  12. Simulation of polarization-dependent film with subwavelength nano-hole array

    Science.gov (United States)

    Yu, Yue; Wei, Dong; Long, Huabao; Xin, Zhaowei; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

    2018-02-01

    When lightwave passes through a metal thin film with a periodic subwavelength hole arrays structure, its transmittance is significantly improved in the partial band compared to other wavelength. Changing the size of the hole, the period or metal material, will make the transmission curve different. Here, we add a layer of dielectric material on the surface of the metal film, such as liquid crystal(LC), by controlling voltage on LC to change the refractive index of this layer, then we can change the transmission curve, and achieve using voltage to move the transmission curve. When there is need for polarization, the holes can be made of a rectangle whose length and width are different or other shapes, for different polarization state of the light, and the film will display different transmission characteristics.

  13. Radar cross section of dipole phased arrays with parallel feed network

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents the detailed analytical formulation for the RCS of parallel-fed linear dipole array in the presence of mutual coupling. The radar cross section (RCS) of an object represents its electromagnetic (EM) scattering properties for a given incident wave. The analysis of scattered field is critical in military and defence arenas, especially while designing low-observable platforms. It is well-known that the presence of an antenna/array on the target influences its echo area significantly. The primary cause for such scattering of the incident signals is reflection that occurs within the antenna aperture and its feed network. In this book, the RCS estimation is done based on the signal path within the antenna system. The scattered field is expressed in terms of array design parameters including the reflection and transmission coefficients. The computed results show the variation in the RCS pattern with and without mutual coupling. The effect of finite dipole-length, inter-element spacing, scan angle,...

  14. Improvement of RF Wireless Power Transmission Using a Circularly Polarized Retrodirective Antenna Array with EBG Structures

    Directory of Open Access Journals (Sweden)

    Son Trinh-Van

    2018-02-01

    Full Text Available This paper presents the performance improvement of a circularly polarized (CP retrodirective array (RDA through the suppression of mutual coupling effects. The RDA is designed based on CP Koch-shaped patch antenna elements with an inter-element spacing as small as 0.4 λ for a compact size ( λ is the wavelength in free space at the designed frequency of 5.2 GHz. Electromagnetic band gap (EBG structures are applied to reduce the mutual coupling between the antenna elements, thus improving the circular polarization characteristic of the RDA. Two CP RDAs with EBGs, in the case 5 × 5 and 10 × 10 arrays, are used as wireless power transmitters to transmit a total power of 50 W. A receiver is located at a distance of 1 m away from the transmitter to harvest the transmitted power. At the broadside direction, the simulated results demonstrate that the received powers are improved by approximately 11.32% and 12.45% when using the 5 × 5 and 10 × 10 CP RDAs with the EBGs, respectively, as the transmitters.

  15. LONG-TERM CALIBRATION STABILITY OF A RADIO ASTRONOMICAL PHASED ARRAY FEED

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, Michael; Jeffs, Brian D.; Warnick, Karl F. [Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 (United States)

    2013-01-01

    There are many challenges associated with the implementation of a phased array feed for radio astronomy applications. Among these is the need to have an adequate set of calibration measurements so that reliable beamformers can be computed. Changes in the operating environment and temporal gain drift in the electronics contribute to calibration drift, which affects the beamformer performance. We will show that calibration measurements are relatively stable over a 5 day period and may remain so for up to 70 days or longer. We have incorporated the use of a calibration update system that has the potential to refresh a set of old calibrators, specifically correcting for electronic gain drift. However, the long-term variations that are present with fresh, current calibrators are greater than the degradation due to using an old calibration set, suggesting that, at this time, there is not a need for sophisticated calibration update systems or algorithms.

  16. Cosmic non-TEM radiation and synthetic feed array sensor system in ASIC mixed signal technology

    Science.gov (United States)

    Centureli, F.; Scotti, G.; Tommasino, P.; Trifiletti, A.; Romano, F.; Cimmino, R.; Saitto, A.

    2014-08-01

    The paper deals with the opportunity to introduce "Not strictly TEM waves" Synthetic detection Method (NTSM), consisting in a Three Axis Digital Beam Processing (3ADBP), to enhance the performances of radio telescope and sensor systems. Current Radio Telescopes generally use the classic 3D "TEM waves" approximation Detection Method, which consists in a linear tomography process (Single or Dual axis beam forming processing) neglecting the small z component. The Synthetic FEED ARRAY three axis Sensor SYSTEM is an innovative technique using a synthetic detection of the generic "NOT strictly TEM Waves radiation coming from the Cosmo, which processes longitudinal component of Angular Momentum too. Than the simultaneous extraction from radiation of both the linear and quadratic information component, may reduce the complexity to reconstruct the Early Universe in the different requested scales. This next order approximation detection of the observed cosmologic processes, may improve the efficacy of the statistical numerical model used to elaborate the same information acquired. The present work focuses on detection of such waves at carrier frequencies in the bands ranging from LF to MMW. The work shows in further detail the new generation of on line programmable and reconfigurable Mixed Signal ASIC technology that made possible the innovative Synthetic Sensor. Furthermore the paper shows the ability of such technique to increase the Radio Telescope Array Antenna performances.

  17. Plasmonic non-concentric nanorings array as an unidirectional nano-optical conveyor belt actuated by polarization rotation.

    Science.gov (United States)

    Jiang, Min; Wang, Guanghui; Jiao, Wenxiang; Ying, Zhoufeng; Zou, Ningmu; Ho, Ho-Pui; Sun, Tianyu; Zhang, Xuping

    2017-01-15

    We report a nano-optical conveyor belt containing an array of gold plasmonic non-concentric nanorings (PNNRs) for the realization of trapping and unidirectional transportation of nanoparticles through rotating the polarization of an excitation beam. The location of hot spots within an asymmetric plasmonic nanostructure is polarization dependent, thus making it possible to manipulate a trapped target by rotating the incident polarization state. In the case of PNNR, the two poles have highly unbalanced trap potential. This greatly enhances the chance of transferring trapped particles between adjacent PNNRs in a given direction through rotating the polarization. As confirmed by three-dimensional finite-difference time-domain analysis, an array of PNNRs forms an unidirectional nano-optical conveyor belt, which delivers target nanoparticles or biomolecules over a long distance with nanometer accuracy. With the capacity to trap and to transfer, our design offers a versatile scheme for conducting mechanical sample manipulation in many on-chip optofluidic applications.

  18. Application of off-specular polarized neutron reflectometry to measurements on an array of mesoscopic ferromagnetic disks

    International Nuclear Information System (INIS)

    Temst, K.; Van Bael, M. J.; Fritzsche, H.

    2001-01-01

    Using off-specular polarized neutron reflectometry with neutron spin analysis, we determined the magnetic properties of a large array of in-plane magnetized ferromagnetic Co disks. Resonant peaks are clearly observed in the off-specular reflectivity, due to the lateral periodicity of the disk array. Using polarized neutrons, the intensity of the resonant peak in the off-specular reflectivity is studied as a function of the magnetic field applied in the sample plane. Spin analysis of the reflected neutrons reveals the magnetization reversal and saturation within the disks. copyright 2001 American Institute of Physics

  19. Cloth-based hybridization array system for expanded identification of the animal species origin of derived materials in feeds.

    Science.gov (United States)

    Murphy, Johanna; Armour, Jennifer; Blais, Burton W

    2007-12-01

    A cloth-based hybridization array system (CHAS) previously developed for the detection of animal species for which prohibited materials have been specified (cattle, sheep, goat, elk, and deer) has been expanded to include the detection of animal species for which there are no prohibitions (pig and horse) in Canadian and American animal feeds. Animal species were identified by amplification of mitochondrial DNA sequences by PCR and subsequent hybridization of the amplicons with an array of species-specific oligonucleotide capture probes immobilized on a polyester cloth support, followed by an immunoenzymatic assay of the bound PCR products. The CHAS permitted sensitive and specific detection of meat meals from different animal species blended in a grain-based feed and should provide a useful adjunct to microscopic examination for the identification of prohibited materials in animal feeds.

  20. Biquaternion beamspace with its application to vector-sensor array direction findings and polarization estimations

    Science.gov (United States)

    Li, Dan; Xu, Feng; Jiang, Jing Fei; Zhang, Jian Qiu

    2017-12-01

    In this paper, a biquaternion beamspace, constructed by projecting the original data of an electromagnetic vector-sensor array into a subspace of a lower dimension via a quaternion transformation matrix, is first proposed. To estimate the direction and polarization angles of sources, biquaternion beamspace multiple signal classification (BB-MUSIC) estimators are then formulated. The analytical results show that the biquaternion beamspaces offer us some additional degrees of freedom to simultaneously achieve three goals. One is to save the memory spaces for storing the data covariance matrix and reduce the computation efforts of the eigen-decomposition. Another is to decouple the estimations of the sources' polarization parameters from those of their direction angles. The other is to blindly whiten the coherent noise of the six constituent antennas in each vector-sensor. It is also shown that the existing biquaternion multiple signal classification (BQ-MUSIC) estimator is a specific case of our BB-MUSIC ones. The simulation results verify the correctness and effectiveness of the analytical ones.

  1. A New Dual Circularly Polarized Feed Employing a Dielectric Cylinder-Loaded Circular Waveguide Open End Fed by Crossed Dipoles

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Bang

    2016-01-01

    Full Text Available This paper presents a new dual circularly polarized feed that provides good axial ratio over wide angles and low cross-polarized radiation in backward direction. A circular waveguide open end is fed with two orthogonally polarized waves in phase quadrature by a pair of printed crossed dipoles and a compact connectorized quadrature hybrid coupler. The waveguide aperture is loaded with a dielectric cylinder to reduce the cross-polarization beyond 90 degrees off the boresight. The fabricated feed has, at 5.5 GHz, 6.33-dBic copolarized gain, 3-dB beamwidth of 106°, 10-dB beamwidth of 195°, 3-dB axial ratio beamwidth of 215°, maximum cross-polarized gain of −21.4 dBic, and 27-dB port isolation. The reflection coefficient of the feed is less than −10 dB at 4.99–6.09 GHz.

  2. Next generation sub-millimeter wave focal plane array coupling concepts: an ESA TRP project to develop multichroic focal plane pixels for future CMB polarization experiments

    Science.gov (United States)

    Trappe, N.; Bucher, M.; De Bernardis, P.; Delabrouille, J.; Deo, P.; DePetris, M.; Doherty, S.; Ghribi, A.; Gradziel, M.; Kuzmin, L.; Maffei, B.; Mahashabde, S.; Masi, S.; Murphy, J. A.; Noviello, F.; O'Sullivan, C.; Pagano, L.; Piacentini, F.; Piat, M.; Pisano, G.; Robinson, M.; Stompor, R.; Tartari, A.; van der Vorst, M.; Verhoeve, P.

    2016-07-01

    The main objective of this activity is to develop new focal plane coupling array concepts and technologies that optimise the coupling from reflector optics to the large number of detectors for next generation sub millimetre wave telescopes particularly targeting measurement of the polarization of the cosmic microwave background (CMB). In this 18 month TRP programme the consortium are tasked with developing, manufacturing and experimentally verifying a prototype multichroic pixel which would be suitable for the large focal plane arrays which will be demanded to reach the required sensitivity of future CMB polarization missions. One major development was to have multichroic operation to potentially reduce the required focal plane size of a CMB mission. After research in the optimum telescope design and definition of requirements based on a stringent science case review, a number of compact focal plane architecture concepts were investigated before a pixel demonstrator consisting of a planar mesh lens feeding a backend Resonant Cold Electron Bolometer RCEB for filtering and detection of the dual frequency signal was planned for manufacture and test. In this demonstrator the frequencies of the channels was chosen to be 75 and 105 GHz in the w band close to the peak CMB signal. In the next year the prototype breadboards will be developed to test the beams produced by the manufactured flat lenses fed by a variety of antenna configurations and the spectral response of the RCEBs will also be verified.

  3. Effect of Beam Scanning on Target Polarization Scattering Matrix Observed by Fully Polarimetric Phased-array Radar

    Directory of Open Access Journals (Sweden)

    Li Mianquan

    2016-04-01

    Full Text Available The polarization feature of a fully Polarimetric Phased-Array Radar (PPAR antenna varies according to the beam-scanning angle, thereby introducing two problems on the target Polarization Scattering Matrix (PSM measurement. First, the antenna polarization basis is defined within the vertical cross-section of an electromagnetic wave propagation direction, and the polarization basis of each beam direction angle is not identical, resulting in the PSM of a fixed-posture target observed by PPAR being not identical for different beam-scanning angles. Second, the cross polarization of the PPAR antenna increases with increasing beamscanning angle, resulting in a crosstalk among the elements of PSM observed by PPAR. This study focuses on the analysis of the abovementioned two aspects of the effect of beam scanning on target PSM observed by PPAR. The results will establish a more accurate observation of the equation for the precision PSM measurement of PPAR.

  4. DOA and Polarization Estimation Using an Electromagnetic Vector Sensor Uniform Circular Array Based on the ESPRIT Algorithm.

    Science.gov (United States)

    Wu, Na; Qu, Zhiyu; Si, Weijian; Jiao, Shuhong

    2016-12-13

    In array signal processing systems, the direction of arrival (DOA) and polarization of signals based on uniform linear or rectangular sensor arrays are generally obtained by rotational invariance techniques (ESPRIT). However, since the ESPRIT algorithm relies on the rotational invariant structure of the received data, it cannot be applied to electromagnetic vector sensor arrays (EVSAs) featuring uniform circular patterns. To overcome this limitation, a fourth-order cumulant-based ESPRIT algorithm is proposed in this paper, for joint estimation of DOA and polarization based on a uniform circular EVSA. The proposed algorithm utilizes the fourth-order cumulant to obtain a virtual extended array of a uniform circular EVSA, from which the pairs of rotation invariant sub-arrays are obtained. The ESPRIT algorithm and parameter pair matching are then utilized to estimate the DOA and polarization of the incident signals. The closed-form parameter estimation algorithm can effectively reduce the computational complexity of the joint estimation, which has been demonstrated by numerical simulations.

  5. Simulation of a circular phased array for a portable ultrasonic polar scan

    Science.gov (United States)

    Daemen, Jannes; Kersemans, Mathias; Martens, Arvid; Verboven, Erik; Delrue, Steven; Van Paepegem, Wim; Degrieck, Joris; Van Den Abeele, Koen

    2018-04-01

    The development of new composite materials, often anisotropic in nature, requires intricate approaches to characterize these materials and to detect internal defects. The Ultrasonic Polar Scan (UPS) is able to achieve both goals. During an UPS experiment, a material spot is insonified at several angles Ψ(θ,ϕ), after which the reflected or transmitted signal is recorded. While excellent results have been obtained using an in-house developed 5-axis scanner, UPS measurements with the current set-up are too lengthy and cumbersome for in-situ industrial application. Therefore, we propose to replace the complex mechanical steering of the transducers by a hemispherical phased array consisting of small PZT elements. This allows to create a compact and portable setup without compromising the current data quality. By successively activating a specific set of elements of the array and choosing appropriate inter-element time delays, the beam can be electronically steered from any angle to a fixed position on the targeted sample. Consequently, UPS reflection measurements can be performed at this position from a wide range of angles in a timeframe of seconds. Additionally, by using apodization windows, it is possible to efficiently reduce the intensity of unwanted side lobes and to create a phase profile which closely resembles that of a bounded plane wave, leading to an easier interpretation of the recorded data. The appropriate time delays and apodization parameters can be found though a multi-objective inverse problem in which both the phase profile and the side lobe reduction are optimized. This approach enables the creation of an effective beam profile to be used during UPS experiments for the characterization and inspection of composite materials. Our simulation approach is a crucial step towards a next-generation UPS device for industrial applications and in-field measurements.

  6. Compact 1 × 2 and 2 × 2 Dual Polarized Series-Fed Antenna Array for X-Band Airborne Synthetic Aperture Radar Applications

    Directory of Open Access Journals (Sweden)

    Venkata Kishore Kothapudi

    2018-04-01

    Full Text Available In this paper, compact linear dual polarized series-fed 1 × 2 linear and 2 × 2 planar arrays antennas for airborne SAR applications are proposed. The proposed antenna design consists of a square radiating patch that is placed on top of the substrate, a quarter wave transformer and 50-Ω matched transformer. Matching between a radiating patch and the 50-Ω microstrip line is accomplished through a direct coupled-feed technique with the help of an impedance inverter (λ/4 impedance transformer placed at both horizontal and vertical planes, in the case of the 2 × 2 planar array. The overall size for the prototype-1 and prototype-2 fabricated antennas are 1.9305 × 0.9652 × 0.05106 λ03 and 1.9305 × 1.9305 × 0.05106 λ03, respectively. The fabricated structure has been tested, and the experimental results are similar to the simulated ones. The CST MWS simulated and vector network analyzer measured reflection coefficient (S11 results were compared, and they indicate that the proposed antenna prototype-1 yields the impedance bandwidth > 140 MHz (9.56–9.72 GHz defined by S11 140 MHz for all the individual ports. The surface currents and the E- and H-field distributions were studied for a better understanding of the polarization mechanism. The measured results of the proposed dual polarized antenna were in accordance with the simulated analysis and showed good performance of the S-parameters and radiation patterns (co-pol and cross-pol, gain, efficiency, front-to-back ratio, half-power beam width at the resonant frequency. With these features and its compact size, the proposed antenna will be suitable for X-band airborne synthetic aperture radar applications.

  7. Wideband metamaterial array with polarization-independent and wide incident angle for harvesting ambient electromagnetic energy and wireless power transfer

    Science.gov (United States)

    Zhong, Hui-Teng; Yang, Xue-Xia; Song, Xing-Tang; Guo, Zhen-Yue; Yu, Fan

    2017-11-01

    In this work, we introduced the design, demonstration, and discussion of a wideband metamaterial array with polarization-independent and wide-angle for harvesting ambient electromagnetic (EM) energy and wireless power transfer. The array consists of unit cells with one square ring and four metal bars. In comparison to the published metamaterial arrays for harvesting EM energy or wireless transfer, this design had the wide operation bandwidth with the HPBW (Half Power Band Width) of 110% (6.2 GHz-21.4 GHz), which overcomes the narrow-band operation induced by the resonance characteristic of the metamaterial. On the normal incidence, the simulated maximum harvesting efficiency was 96% and the HPBW was 110% for the random polarization wave. As the incident angle increases to 45°, the maximum efficiency remained higher than 88% and the HPBW remained higher than 83% for the random polarization wave. Furthermore, the experimental verification of the designed metamaterial array was conducted, and the measured results were in reasonable agreement with the simulated ones.

  8. Novel Microstrip Patch Antennas with Frequency Agility, Polarization Reconfigurability, Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance

    Science.gov (United States)

    Babakhani, Behrouz

    Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency

  9. Imaging, object detection, and change detection with a polarized multistatic GPR array

    Science.gov (United States)

    Beer, N. Reginald; Paglieroni, David W.

    2015-07-21

    A polarized detection system performs imaging, object detection, and change detection factoring in the orientation of an object relative to the orientation of transceivers. The polarized detection system may operate on one of several modes of operation based on whether the imaging, object detection, or change detection is performed separately for each transceiver orientation. In combined change mode, the polarized detection system performs imaging, object detection, and change detection separately for each transceiver orientation, and then combines changes across polarizations. In combined object mode, the polarized detection system performs imaging and object detection separately for each transceiver orientation, and then combines objects across polarizations and performs change detection on the result. In combined image mode, the polarized detection system performs imaging separately for each transceiver orientation, and then combines images across polarizations and performs object detection followed by change detection on the result.

  10. An initial analysis of options for a UK feed-in tariff for photovoltaic energy, from an array owner's viewpoint

    International Nuclear Information System (INIS)

    Plater, Steve

    2009-01-01

    The UK government has announced the introduction from April 2010 of a feed-in tariff (FIT) for renewable energy, and initiated a consultation on its design. This paper compares three possible variants of a UK FIT for rooftop photovoltaic (PV) arrays, on the basis of calculated income and array cost payback time, and for three locations (north, central and southern England) and various levels of household electricity consumption. This modelling is based on an FIT rate equivalent to Germany's. It concludes that an FIT which paid only for PV electricity surplus to on-site needs, and exported to the grid, would mean a simple payback time too long to make array purchase appealing. Preferable would be either export to the grid of all PV electricity for FIT payment; or a lower FIT rate for electricity used on-site, plus full FIT for any surplus exported. The latter would involve significantly lower costs in feed-in tariff payments. Finally, the effect of the UK government's illustrative FIT rate for consultation is examined for the same locations and annual consumption levels.

  11. High-resolution two-dimensional and three-dimensional modeling of wire grid polarizers and micropolarizer arrays

    Science.gov (United States)

    Vorobiev, Dmitry; Ninkov, Zoran

    2017-11-01

    Recent advances in photolithography allowed the fabrication of high-quality wire grid polarizers for the visible and near-infrared regimes. In turn, micropolarizer arrays (MPAs) based on wire grid polarizers have been developed and used to construct compact, versatile imaging polarimeters. However, the contrast and throughput of these polarimeters are significantly worse than one might expect based on the performance of large area wire grid polarizers or MPAs, alone. We investigate the parameters that affect the performance of wire grid polarizers and MPAs, using high-resolution two-dimensional and three-dimensional (3-D) finite-difference time-domain simulations. We pay special attention to numerical errors and other challenges that arise in models of these and other subwavelength optical devices. Our tests show that simulations of these structures in the visible and near-IR begin to converge numerically when the mesh size is smaller than ˜4 nm. The performance of wire grid polarizers is very sensitive to the shape, spacing, and conductivity of the metal wires. Using 3-D simulations of micropolarizer "superpixels," we directly study the cross talk due to diffraction at the edges of each micropolarizer, which decreases the contrast of MPAs to ˜200∶1.

  12. Scalable Direct Writing of Lanthanide-Doped KMnF3 Perovskite Nanowires into Aligned Arrays with Polarized Up-Conversion Emission.

    Science.gov (United States)

    Shi, Shuo; Sun, Ling-Dong; Xue, Ying-Xian; Dong, Hao; Wu, Ke; Guo, Shi-Chen; Wu, Bo-Tao; Yan, Chun-Hua

    2018-05-09

    The use of one-dimensional nano- and microstructured semiconductor and lanthanide materials is attractive for polarized-light-emission studies. Up-conversion emission from single-nanorod or anisotropic nanoparticles with a degree of polarization has also been discussed. However, microscale arrays of nanoparticles, especially well-aligned one-dimensional nanostructures as well as their up-conversion polarization characterization, have not been investigated yet. Herein, we present a novel and facile paradigm for preparing highly aligned arrays of lanthanide-doped KMnF 3 (KMnF 3 :Ln) perovskite nanowires, which are good candidates for polarized up-conversion emission studies. These perovskite nanowires, with a width of 10 nm and length of a few micrometers, are formed through the oriented attachment of KMnF 3 :Ln nanocubes along the [001] direction. By the employment of KMnF 3 :Ln nanowire gel as nanoink, a direct-writing method is developed to obtain diverse types of aligned patterns from the nanoscale to the wafer scale. Up-conversion emissions from the highly aligned nanowire arrays are polarized along the array direction with a polarization degree up to 60%. Taking advantage of microscopic nanowire arrays, these polarized up-conversion emissions should offer potential applications in light or information transportation.

  13. Flashed-feed VMD configuration as a novel method for eliminating temperature polarization effect and enhancing water vapor flux

    KAUST Repository

    Alsaadi, Ahmad Salem

    2018-05-28

    The coupling of heat and mass transfer in membrane distillation (MD) process makes enhancing water vapor flux and determining MD membrane mass transfer coefficient (MTC) fairly challenging due to the development of temperature gradient near the membrane surface, referred to as temperature polarization (TP). As a result, the change in feed temperature at the membrane surface will be difficult to measure accurately. In this paper, the effect of TP was decoupled from the membrane MTC by preventing the liquid feed stream from contacting the membrane surface through the use of a novel custom-made vacuum MD (VMD) module design. Results showed that a temperature difference of 10°C between the feed bulk and feed temperatures at the membrane surface/interface is estimated to take place in the typical VMD configuration, while the proposed flashed-feed VMD configuration eliminates TP effect and gives a flux 3.5-fold higher (200kg/m2.hr) under similar operating conditions. Therefore, it can be concluded that heat transfer coefficient is considered to be the main factor controlling resistance of water vapor flux in the typical VMD configuration. The measured MTC of the tested commercial membrane was found to be more accurate and the highest among all reported MTCs in the MD literature (2.44×10−6kg/m2.s.Pa). Additionally, a transmembrane temperature difference of 5°C and 10°C in the novel configuration can produce water vapor fluxes of about 9kg/m2.hr and 40kg/m2.hr, respectively, at a feed temperature of 70°C, which is very attractive for scaling-up the process.

  14. Production of highly polarized 3He using spectrally narrowed diode laser array bars

    International Nuclear Information System (INIS)

    Chann, B.; Babcock, E.; Anderson, L.W.; Walker, T.G.; Chen, W.C.; Smith, T.B.; Thompson, A.K.; Gentile, T.R.

    2003-01-01

    We have produced 70%-75% 3 He polarization by spin-exchange optical pumping in cells ≅100 cm 3 in volume. The polarization achieved is consistent with known spin-exchange and spin-relaxation rates, but only when the recently discovered temperature dependence of 3 He relaxation is included. Absolute 3 He polarization measurements were performed using two different methods in two different laboratories. The results were obtained with either a spectrally narrowed laser or one type of broadband laser. Based on tests of several larger cells at pressures near 1 bar, we find that the power required to reach the same polarization is typically three times lower for the spectrally narrowed laser. This last result indicates that spectrally narrowed lasers will be important for obtaining the highest polarization in large volume neutron spin filters. Polarization in excess of 55% as obtained in cells up to 640 cm 3 in volume and 70% polarization is anticipated with available increases in spectrally narrowed laser power

  15. Large arrays of dual-polarized multichroic TES detectors for CMB measurements with the SPT-3G receiver

    Science.gov (United States)

    Posada, Chrystian M.; Ade, Peter A. R.; Anderson, Adam J.; Avva, Jessica; Ahmed, Zeeshan; Arnold, Kam S.; Austermann, Jason; Bender, Amy N.; Benson, Bradford A.; Bleem, Lindsey; Byrum, Karen; Carlstrom, John E.; Carter, Faustin W.; Chang, Clarence; Cho, Hsiao-Mei; Cukierman, Ari; Czaplewski, David A.; Ding, Junjia; Divan, Ralu N. S.; de Haan, Tijmen; Dobbs, Matt; Dutcher, Daniel; Everett, Wenderline; Gannon, Renae N.; Guyser, Robert J.; Halverson, Nils W.; Harrington, Nicholas L.; Hattori, Kaori; Henning, Jason W.; Hilton, Gene C.; Holzapfel, William L.; Huang, Nicholas; Irwin, Kent D.; Jeong, Oliver; Khaire, Trupti; Korman, Milo; Kubik, Donna L.; Kuo, Chao-Lin; Lee, Adrian T.; Leitch, Erik M.; Lendinez Escudero, Sergi; Meyer, Stephan S.; Miller, Christina S.; Montgomery, Joshua; Nadolski, Andrew; Natoli, Tyler J.; Nguyen, Hogan; Novosad, Valentyn; Padin, Stephen; Pan, Zhaodi; Pearson, John E.; Rahlin, Alexandra; Reichardt, Christian L.; Ruhl, John E.; Saliwanchik, Benjamin; Shirley, Ian; Sayre, James T.; Shariff, Jamil A.; Shirokoff, Erik D.; Stan, Liliana; Stark, Antony A.; Sobrin, Joshua; Story, Kyle; Suzuki, Aritoki; Tang, Qing Yang; Thakur, Ritoban B.; Thompson, Keith L.; Tucker, Carole E.; Vanderlinde, Keith; Vieira, Joaquin D.; Wang, Gensheng; Whitehorn, Nathan; Yefremenko, Volodymyr; Yoon, Ki Won

    2016-07-01

    Detectors for cosmic microwave background (CMB) experiments are now essentially background limited, so a straightforward alternative to improve sensitivity is to increase the number of detectors. Large arrays of multichroic pixels constitute an economical approach to increasing the number of detectors within a given focal plane area. Here, we present the fabrication of large arrays of dual-polarized multichroic transition-edge-sensor (TES) bolometers for the South Pole Telescope third-generation CMB receiver (SPT-3G). The complete SPT-3G receiver will have 2690 pixels, each with six detectors, allowing for individual measurement of three spectral bands (centered at 95 GHz, 150 GHz and 220 GHz) in two orthogonal polarizations. In total, the SPT-3G focal plane will have 16140 detectors. Each pixel is comprised of a broad-band sinuous antenna coupled to a niobium microstrip transmission line. In-line filters are used to define the different band-passes before the millimeter-wavelength signal is fed to the respective Ti/Au TES sensors. Detectors are read out using a 64x frequency domain multiplexing (fMux) scheme. The microfabrication of the SPT-3G detector arrays involves a total of 18 processes, including 13 lithography steps. Together with the fabrication process, the effect of processing on the Ti/Au TES's Tc is discussed. In addition, detectors fabricated with Ti/Au TES films with Tc between 400 mK 560 mK are presented and their thermal characteristics are evaluated. Optical characterization of the arrays is presented as well, indicating that the response of the detectors is in good agreement with the design values for all three spectral bands (95 GHz, 150 GHz, and 220 GHz). The measured optical efficiency of the detectors is between 0.3 and 0.8. Results discussed here are extracted from a batch of research of development wafers used to develop the baseline process for the fabrication of the arrays of detectors to be deployed with the SPT-3G receiver. Results from

  16. CONSTRAINING POLARIZED FOREGROUNDS FOR EoR EXPERIMENTS. I. 2D POWER SPECTRA FROM THE PAPER-32 IMAGING ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S. A.; Aguirre, J. E.; Moore, D. F. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Nunhokee, C. D.; Bernardi, G. [Department of Physics and Electronics, Rhodes University, Grahamstown (South Africa); Pober, J. C. [Department of Physics, Brown University, Providence, RI (United States); Ali, Z. S.; DeBoer, D. R.; Parsons, A. R. [Astronomy Department, University of California, Berkeley, CA (United States); Bradley, R. F. [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA (United States); Carilli, C. L. [National Radio Astronomy Observatory, Socorro, NM (United States); Gugliucci, N. E. [Saint Anselm College, Manchester, NH (United States); Jacobs, D. C. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Klima, P. [National Radio Astronomy Observatory, Charlottesville, VA (United States); MacMahon, D. H. E. [Radio Astronomy Laboratory, University of California, Berkeley, CA (United States); Manley, J. R.; Walbrugh, W. P. [SKA South Africa, Pinelands (South Africa); Stefan, I. I., E-mail: saulkohn@sas.upenn.edu [Cavendish Laboratory, Cambridge (United Kingdom)

    2016-06-01

    Current generation low-frequency interferometers constructed with the objective of detecting the high-redshift 21 cm background aim to generate power spectra of the brightness temperature contrast of neutral hydrogen in primordial intergalactic medium. Two-dimensional (2D) power spectra (power in Fourier modes parallel and perpendicular to the line of sight) that formed from interferometric visibilities have been shown to delineate a boundary between spectrally smooth foregrounds (known as the wedge ) and spectrally structured 21 cm background emission (the EoR window ). However, polarized foregrounds are known to possess spectral structure due to Faraday rotation, which can leak into the EoR window. In this work we create and analyze 2D power spectra from the PAPER-32 imaging array in Stokes I, Q, U, and V. These allow us to observe and diagnose systematic effects in our calibration at high signal-to-noise within the Fourier space most relevant to EoR experiments. We observe well-defined windows in the Stokes visibilities, with Stokes Q, U, and V power spectra sharing a similar wedge shape to that seen in Stokes I. With modest polarization calibration, we see no evidence that polarization calibration errors move power outside the wedge in any Stokes visibility to the noise levels attained. Deeper integrations will be required to confirm that this behavior persists to the depth required for EoR detection.

  17. Highly doped semiconductor plasmonic nanoantenna arrays for polarization selective broadband surface-enhanced infrared absorption spectroscopy of vanillin

    Science.gov (United States)

    Barho, Franziska B.; Gonzalez-Posada, Fernando; Milla, Maria-Jose; Bomers, Mario; Cerutti, Laurent; Tournié, Eric; Taliercio, Thierry

    2017-11-01

    Tailored plasmonic nanoantennas are needed for diverse applications, among those sensing. Surface-enhanced infrared absorption (SEIRA) spectroscopy using adapted nanoantenna substrates is an efficient technique for the selective detection of molecules by their vibrational spectra, even in small quantity. Highly doped semiconductors have been proposed as innovative materials for plasmonics, especially for more flexibility concerning the targeted spectral range. Here, we report on rectangular-shaped, highly Si-doped InAsSb nanoantennas sustaining polarization switchable longitudinal and transverse plasmonic resonances in the mid-infrared. For small array periodicities, the highest reflectance intensity is obtained. Large periodicities can be used to combine localized surface plasmon resonances (SPR) with array resonances, as shown in electromagnetic calculations. The nanoantenna arrays can be efficiently used for broadband SEIRA spectroscopy, exploiting the spectral overlap between the large longitudinal or transverse plasmonic resonances and narrow infrared active absorption features of an analyte molecule. We demonstrate an increase of the vibrational line intensity up to a factor of 5.7 of infrared-active absorption features of vanillin in the fingerprint spectral region, yielding enhancement factors of three to four orders of magnitude. Moreover, an optimized readout for SPR sensing is proposed based on slightly overlapping longitudinal and transverse localized SPR.

  18. Highly doped semiconductor plasmonic nanoantenna arrays for polarization selective broadband surface-enhanced infrared absorption spectroscopy of vanillin

    Directory of Open Access Journals (Sweden)

    Barho Franziska B.

    2017-11-01

    Full Text Available Tailored plasmonic nanoantennas are needed for diverse applications, among those sensing. Surface-enhanced infrared absorption (SEIRA spectroscopy using adapted nanoantenna substrates is an efficient technique for the selective detection of molecules by their vibrational spectra, even in small quantity. Highly doped semiconductors have been proposed as innovative materials for plasmonics, especially for more flexibility concerning the targeted spectral range. Here, we report on rectangular-shaped, highly Si-doped InAsSb nanoantennas sustaining polarization switchable longitudinal and transverse plasmonic resonances in the mid-infrared. For small array periodicities, the highest reflectance intensity is obtained. Large periodicities can be used to combine localized surface plasmon resonances (SPR with array resonances, as shown in electromagnetic calculations. The nanoantenna arrays can be efficiently used for broadband SEIRA spectroscopy, exploiting the spectral overlap between the large longitudinal or transverse plasmonic resonances and narrow infrared active absorption features of an analyte molecule. We demonstrate an increase of the vibrational line intensity up to a factor of 5.7 of infrared-active absorption features of vanillin in the fingerprint spectral region, yielding enhancement factors of three to four orders of magnitude. Moreover, an optimized readout for SPR sensing is proposed based on slightly overlapping longitudinal and transverse localized SPR.

  19. Amplitude and Phase Calibration of an Dual Polarized Active Phased Array Antenna

    NARCIS (Netherlands)

    Vermeulen, B.C.B.; Paquay, M.H.A.; Koomen, P.J.; Hoogeboom, P.; Snoeij, P.; Pouwels, H.

    1996-01-01

    In the Netherlands, a Polarimetrie C-band aircraft SAR (Synthetic Aperture Radar) has been developed. The project is called PHARUS, an acronym for Phased Array Universal SAR. This instrument serves remote sensing applications. The antenna system contains 48 modules (expandable to 96). A module is

  20. Dielectrophoretic self-assembly of polarized light emitting poly(9,9-dioctylfluorene) nanofibre arrays

    International Nuclear Information System (INIS)

    O'Riordan, A; Iacopino, D; Lovera, P; Floyd, L; Reynolds, K; Redmond, G

    2011-01-01

    Conjugated polymer based 1D nanostructures are attractive building blocks for future opto-electronic nanoscale devices and systems. However, a critical challenge remains the lack of manipulation methods that enable controlled and reliable positioning and orientation of organic nanostructures in a fast, reliable and scalable manner. To address this challenge, we explore dielectrophoretic assembly of discrete poly(9,9-dioctylfluorene) nanofibres and demonstrate site selective assembly and orientation of these fibres. Nanofibre arrays were assembled preferentially at receptor electrode edges, being aligned parallel to the applied electric field with a high order parameter fit (∼0.9) and exhibiting an emission dichroic ratio of ∼ 4.0. As such, the dielectrophoretic method represents a fast, reliable and scalable self-assembly approach for manipulation of 1D organic nanostructures. The ability to fabricate nanofibre arrays in this manner could be potentially important for exploration and development of future nanoscale opto-electronic devices and systems.

  1. Studies of Polar Current Systems Using the IMS Scandinavian Magnetometer Array

    Science.gov (United States)

    Untiedt, J.; Baumjohann, W.

    1993-09-01

    As a contribution to the International Magnetospheric Study (IMS, 1976 1979) a two-dimensional array of 42 temporary magnetometer stations was run in Scandinavia, supplementary to the permanent observatories and concentrated in the northern part of the region. This effort aimed at the time-dependent (periods above about 100 s) determination of the two-dimensional structure of substorm-related magnetic fields at the Earth's surface with highest reasonable spatial resolution (about 100 km, corresponding to the height of the ionosphere) near the footpoints of field-aligned electric currents that couple the disturbed magnetosphere to the ionosphere at auroral latitudes. It has been of particular advantage for cooperative studies that not only simultaneous data were available from all-sky cameras, riometers, balloons, rockets, and satellites, but also from the STARE radar facility yielding colocated two-dimensional ionospheric electric field distributions. In many cases it therefore was possible to infer the three-dimensional regional structure of substorm-related ionospheric current systems. The first part of this review outlines the basic relationships and methods that have been used or have been developed for such studies. The second short part presents typical equivalent current patterns observed by the magnetometer array in the course of substorms. Finally we review main results of studies that have been based on the magnetometer array observations and on additional data, omitting studies on geomagnetic pulsations. These studies contributed to a clarification of the nature of auroral electrojets including the Harang discontinuity and of ionospheric current systems related to auroral features such as the break-up at midnight, the westward traveling surge, eastward drifting omega bands, and spirals.

  2. Effect of slaughter age and feeding system on the neutral and polar lipid composition of horse meat.

    Science.gov (United States)

    Belaunzaran, X; Lavín, P; Mantecón, A R; Kramer, J K G; Aldai, N

    2018-02-01

    This study was undertaken to provide a thorough analysis of the neutral lipid (NL) and polar lipid (PL) fractions of horse meat that included the content and distribution of acyl and alkenyl moieties in foals under different rearing conditions. Two groups of crossbred horses were studied; the first group was selected from suckling foals produced under grazing conditions and slaughtered at 4 months of age (n=8), and the second group was selected from concentrate-finished foals and slaughtered at 12 months of age (n=7). There were significant differences related to the age and feeding practices of foals which affected the intramuscular (IM) fat content and the fatty acid (FA) composition of NL and PL fractions. Samples from suckling foals were leaner and provided the highest content of methylation products from the plasmalogenic lipids, and total and n-3 polyunsaturated fatty acid (PUFA). By contrast, the meat from concentrate-finished foals had a higher IM fat level resulting in a greater accumulation of 16:0 and total monounsaturated FAs in the NL fraction, whereas the muscle PL fraction retained a similar FA composition between both groups. Linolenic acid was preferentially deposited in the NL fraction, but linoleic acid and the long-chain n-3 and n-6 PUFAs were incorporated into the PL fraction where they served as cell membrane constituents and in eicosanoid formation.

  3. High-performance liquid chromatography ultraviolet-photodiode array detection method for aflatoxin B1 in cattle feed supplements

    Science.gov (United States)

    Mochamad, Lazuardi; Hermanto, Bambang

    2017-01-01

    Aim: The objective of the current study is to determine the concentration of aflatoxin B1 using high-performance liquid chromatography (HPLC) with a photodiode array (PDA) detector. Materials and Methods: Aflatoxin B1 certified reference grade from Trilogy Analytical Laboratory dissolved acetonitrile (ACN) at 10 µg/mL was using standard assessment. HPLC instruments such as ultraviolet-PDA detector used a Shimadzu LC-6AD pump with DGU-20A5 degasser, communication module-20A, and PDA detector SPD-M20A with FRC-10A fraction collector. The HPLC was set isocratic method at 354 nm with a reverse-phase ODS C18 column (LiChrospher® 100 RP-18; diameter, 5 µm) under a 20°C controlled column chamber. Rheodyne® sample loops were performed in 20 µL capacities. The mobile phase was performed at fraction 63:26:11 H2O: methanol:ACN at pH 6.8. A total of 1 kg of feed contained 10% bread crumbs and 30% concentrated, 40% forage, and 20% soybean dregs were using commercials samples. Samples were extracted by ACN and separated with solid phase extraction ODS 1 mL than elution with mobile phase to collect at drying samples performed. The samples were ready to use after added 1 mL mobile phase than injected into the system of HPLC. Results: We found that the retention time of aflatoxin B1 was approximately 10.858 min. Linearity of 0.01-0.08 µg/mL aflatoxin B1 dissolved in mobile phase was obtained at R2=0.9. These results demonstrate that these methods can be used to analyze aflatoxin B1 and gain 89-99% recovery. The limit of detection of this assay was obtained at 3.5 × 10−6 µg/mL. Conclusion: This method was easy to apply and suitable to analyzing at small concentrations of aflatoxin B1 in formulated product of feed cattle. PMID:28919686

  4. Dual-Polarized Antenna Arrays with CMOS Power Amplifiers for SiP Integration at W-Band

    Science.gov (United States)

    Giese, Malte; Vehring, Sönke; Böck, Georg; Jacob, Arne F.

    2017-09-01

    This paper presents requirements and front-end solutions for low-cost communication systems with data rates of 100 Gbit/s. Link budget analyses in different mass-market applications are conducted for that purpose. It proposes an implementation of the front-end as an active antenna array with support for beam steering and polarization multiplexing over the full W-band. The critical system components are investigated and presented. This applies to a transformer coupled power amplifier (PA) in 40 nm bulk CMOS. It shows saturated output power of more than 10 dBm and power-added-efficiency of more than 10 % over the full W-band. Furthermore, the performance of microstrip-to-waveguide transitions is shown exemplarily as an important part of the active antenna as it interfaces active circuitry and antenna in a polymer-and-metal process. The transition test design shows less than 0.9 dB insertion loss and more than 12 dB return loss for the differential transition over the full W-band.

  5. Phased Array Feeds

    Science.gov (United States)

    Fisher, J. Richard; Bradley, Richard F.; Brisken, Walter F.; Cotton, William D.; Emerson, Darrel T.; Kerr, Anthony R.; Lacasse, Richard J.; Morgan, Matthew A.; Napier, Peter J.; Norrod, Roger D.; Payne, John M.; Pospieszalski, Marian W.; Symmes, Arthur; Thompson, A. Richard; Webber, John C.

    2009-03-01

    This white paper offers cautionary observations about the planning and development of new, large radio astronomy instruments. Complexity is a strong cost driver so every effort should be made to assign differing science requirements to different instruments and probably different sites. The appeal of shared resources is generally not realized in practice and can often be counterproductive. Instrument optimization is much more difficult with longer lists of requirements, and the development process is longer and less efficient. More complex instruments are necessarily further behind the technology state of the art because of longer development times. Including technology R&D in the construction phase of projects is a growing trend that leads to higher risks, cost overruns, schedule delays, and project de-scoping. There are no technology breakthroughs just over the horizon that will suddenly bring down the cost of collecting area. Advances come largely through careful attention to detail in the adoption of new technology provided by industry and the commercial market. Radio astronomy instrumentation has a very bright future, but a vigorous long-term R&D program not tied directly to specific projects needs to be restored, fostered, and preserved.

  6. ELECTROMAGNETIC SCATTERING AND ANTENNA TECHNOLOGY (EMSAT) Task Order 0003: Design of a Circularly Polarized, 20 60 GHZ Active Phased Array for Wide Angle Scanning

    Science.gov (United States)

    2017-08-08

    previously published linear -to-circular polarizers. This is because the first sheet has a low inductance in the -direction, which acts as a wire-grid...GHZ Active Phased Array for Wide Angle Scanning Carl R. Pfeiffer Defense Engineering Corporation Boris Tomasic Multispectral Sensing and...GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62204F/61102F 6. AUTHOR(S) Carl R. Pfeiffer (Defense Engineering Corporation) Boris Tomasic (AFRL

  7. Analyzing the propagation behavior of coherence and polarization degrees of a phase-locked partially coherent radial flat-topped array laser beam in underwater turbulence.

    Science.gov (United States)

    Kashani, Fatemeh Dabbagh; Yousefi, Masoud

    2016-08-10

    In this research, based on an analytical expression for cross-spectral density (CSD) matrix elements, coherence and polarization properties of phase-locked partially coherent flat-topped (PCFT) radial array laser beams propagating through weak oceanic turbulence are analyzed. Spectral degrees of coherence and polarization are analytically calculated using CSD matrix elements. Also, the effective width of spatial degree of coherence (EWSDC) is calculated numerically. The simulation is done by considering the effects of source parameters (such as radius of the array setup's circle, effective width of the spectral degree of coherence, and wavelength) and turbulent ocean factors (such as the rate of dissipation of the turbulent kinetic energy per unit mass of fluid and relative strength of temperature and salinity fluctuations, Kolmogorov micro-scale, and rate of dissipation of the mean squared temperature) in detail. Results indicate that any change in the amount of turbulence factors that increase the turbulence power reduces the EWSDC significantly and causes the reduction in the degree of polarization, and occurs at shorter propagation distances but with smaller magnitudes. In addition, being valid for all conditions, the degradation rate of the EWSDC of Gaussian array beams are more in comparison with the PCFT ones. The simulation and calculation results are shown by graphs.

  8. A wideband (3 to 5 GHz) wide-scan connected array of dipoles with low cross polarization

    NARCIS (Netherlands)

    Cavallo, D.; Neto, A.; Gerini, G.

    2012-01-01

    A wideband, wide-scan prototype phased array of connected dipoles has been manufactured and tested from 3 to 5 GHz. The array comprises 7 × 7 elements, each fed by a loop-shaped transformer to avoid common-mode resonances. Such resonances typically affect this type of arrays, with consequent

  9. A Wideband High-Gain Dual-Polarized Slot Array Patch Antenna for WiMAX Applications in 5.8 GHz

    Directory of Open Access Journals (Sweden)

    Amir Reza Dastkhosh

    2012-01-01

    Full Text Available A low-cost, easy-to-fabricate, wideband and high-gain dual-polarized array antenna employing an innovative microstrip slot patch antenna element is designed and fabricated. The design parameters of the antenna are optimized using commercial softwares (Microwave Office and Zeland IE3D to get the suitable -parameters and radiation patterns. Finally, the simulation results are compared to the experimental ones and a good agreement is demonstrated. The antenna has an approximately bandwidth of 14% (5.15–5.9 GHz which covers Worldwide Interoperability Microwave Access (WiMAX/5.8. It also has the peak gain of 26 dBi for both polarizations and high isolation between two ports over a wide bandwidth.

  10. Controlling optical properties of periodic gold nanoparticle arrays by changing the substrate, topologic shapes of nanoparticles, and polarization direction of incident light

    International Nuclear Information System (INIS)

    Ting, Li; Li, Yu; Zhi-Xin, Lu; Gang, Song; Kai, Zhang

    2011-01-01

    The effects of various parameters including thickness and dielectric constants of substrates, shapes of nanoparticles, and polarization direction of incident light, on the extinction spectra of periodic gold nanoparticle arrays are investigated by the full-vectorial three-dimensional (3D) finite difference time domain (FDTD) method. The calculated results show that the substrate affects the extinction spectra by coupling the fields co-excited by the substrate and gold nanoparticles. Extinction spectra are influenced by the shapes of the nanoparticles, but there are no obvious changes in extinction spectra for similar shapes. The polarization direction of incident light has a great influence on the extinction spectra. The implications of these results are discussed. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  11. Study of a 4 elements circularly polarized microstrip antenna array%一种四单元圆极化微带天线阵的研制

    Institute of Scientific and Technical Information of China (English)

    孔祥伟; 丁卫平

    2012-01-01

    本文设计了一种新颖的四单元圆极化微带天线阵。通过去掉单元贴片周围的介质,使天线阵的重量减少了54%。文中采用电磁仿真软件HFSS10进行优化与仿真,讨论了阵元间距对天线阵的增益、半功率波束宽度、旁瓣电平以及后瓣电平的影响。最后加工制作了相应的微带天线阵,测试结果与仿真吻合较好。%A novel 4 elements microstrip antenna array for circular polarization is presented.By cutting out the dielectric substrate around the element,the weight of the array has been reduced by 54%.The array is designed and optimized by HFSS10 software.Effects of the element spacing on the gain,half power,sidelobe level,and backlobe level are investigated.The microstrip array is fabricated and measured and the measured results are in good agreement with the simulated results.

  12. Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations.

    Science.gov (United States)

    Rode, Karyn D; Regehr, Eric V; Douglas, David C; Durner, George; Derocher, Andrew E; Thiemann, Gregory W; Budge, Suzanne M

    2014-01-01

    Polar bears (Ursus maritimus) have experienced substantial changes in the seasonal availability of sea ice habitat in parts of their range, including the Beaufort, Chukchi, and Bering Seas. In this study, we compared the body size, condition, and recruitment of polar bears captured in the Chukchi and Bering Seas (CS) between two periods (1986-1994 and 2008-2011) when declines in sea ice habitat occurred. In addition, we compared metrics for the CS population 2008-2011 with those of the adjacent southern Beaufort Sea (SB) population where loss in sea ice habitat has been associated with declines in body condition, size, recruitment, and survival. We evaluated how variation in body condition and recruitment were related to feeding ecology. Comparing habitat conditions between populations, there were twice as many reduced ice days over continental shelf waters per year during 2008-2011 in the SB than in the CS. CS polar bears were larger and in better condition, and appeared to have higher reproduction than SB bears. Although SB and CS bears had similar diets, twice as many bears were fasting in spring in the SB than in the CS. Between 1986-1994 and 2008-2011, body size, condition, and recruitment indices in the CS were not reduced despite a 44-day increase in the number of reduced ice days. Bears in the CS exhibited large body size, good body condition, and high indices of recruitment compared to most other populations measured to date. Higher biological productivity and prey availability in the CS relative to the SB, and a shorter recent history of reduced sea ice habitat, may explain the maintenance of condition and recruitment of CS bears. Geographic differences in the response of polar bears to climate change are relevant to range-wide forecasts for this and other ice-dependent species. © 2013 John Wiley & Sons Ltd.

  13. Variation in the response of an Arctic top predator experiencing habitat loss: Feeding and reproductive ecology of two polar bear populations

    Science.gov (United States)

    Rode, Karyn D.; Regehr, Eric V.; Douglas, David C.; Durner, George M.; Derocher, Andrew E.; Thiemann, Gregory W.; Budge, Suzanne M.

    2014-01-01

    Polar bears (Ursus maritimus) have experienced substantial changes in the seasonal availability of sea ice habitat in parts of their range, including the Beaufort, Chukchi, and Bering Seas. In this study, we compared the body size, condition, and recruitment of polar bears captured in the Chukchi and Bering Seas (CS) between two periods (1986–1994 and 2008–2011) when declines in sea ice habitat occurred. In addition, we compared metrics for the CS population 2008–2011 with those of the adjacent southern Beaufort Sea (SB) population where loss in sea ice habitat has been associated with declines in body condition, size, recruitment, and survival. We evaluated how variation in body condition and recruitment were related to feeding ecology. Comparing habitat conditions between populations, there were twice as many reduced ice days over continental shelf waters per year during 2008–2011 in the SB than in the CS. CS polar bears were larger and in better condition, and appeared to have higher reproduction than SB bears. Although SB and CS bears had similar diets, twice as many bears were fasting in spring in the SB than in the CS. Between 1986–1994 and 2008–2011, body size, condition, and recruitment indices in the CS were not reduced despite a 44-day increase in the number of reduced ice days. Bears in the CS exhibited large body size, good body condition, and high indices of recruitment compared to most other populations measured to date. Higher biological productivity and prey availability in the CS relative to the SB, and a shorter recent history of reduced sea ice habitat, may explain the maintenance of condition and recruitment of CS bears. Geographic differences in the response of polar bears to climate change are relevant to range-wide forecasts for this and other ice-dependent species.

  14. Polar body array CGH for prediction of the status of the corresponding oocyte. Part II: technical aspects

    NARCIS (Netherlands)

    Magli, M. Cristina; Montag, Markus; Köster, Maria; Muzi, Luigi; Geraedts, Joep; Collins, John; Goossens, Veerle; Handyside, Alan H.; Harper, Joyce; Repping, Sjoerd; Schmutzler, Andreas; Vesela, Katerina; Gianaroli, Luca

    2011-01-01

    The purpose of this study was to assess the technical aspects related to polar body (PB) biopsy, which might have an influence on the results of the microarray comparative genomic hybridization analysis. Furthermore, a comparison was made between two biopsy methods (mechanical and laser). Biopsy of

  15. Polarization leakage in epoch of reionization windows - III. Wide-field effects of narrow-field arrays

    Science.gov (United States)

    Asad, K. M. B.; Koopmans, L. V. E.; Jelić, V.; de Bruyn, A. G.; Pandey, V. N.; Gehlot, B. K.

    2018-05-01

    Leakage of polarized Galactic diffuse emission into total intensity can potentially mimic the 21-cm signal coming from the epoch of reionization (EoR), as both of them might have fluctuating spectral structure. Although we are sensitive to the EoR signal only in small fields of view, chromatic side-lobes from further away can contaminate the inner region. Here, we explore the effects of leakage into the `EoR window' of the cylindrically averaged power spectra (PS) within wide fields of view using both observation and simulation of the 3C196 and North Celestial Pole (NCP) fields, two observing fields of the LOFAR-EoR project. We present the polarization PS of two one-night observations of the two fields and find that the NCP field has higher fluctuations along frequency, and consequently exhibits more power at high-k∥ that could potentially leak to Stokes I. Subsequently, we simulate LOFAR observations of Galactic diffuse polarized emission based on a model to assess what fraction of polarized power leaks into Stokes I because of the primary beam. We find that the rms fractional leakage over the instrumental k-space is 0.35 {per cent} in the 3C196 field and 0.27 {per cent} in the NCP field, and it does not change significantly within the diameters of 15°, 9°, and 4°. Based on the observed PS and simulated fractional leakage, we show that a similar level of leakage into Stokes I is expected in the 3C196 and NCP fields, and the leakage can be considered to be a bias in the PS.

  16. ANN Synthesis Model of Single-Feed Corner-Truncated Circularly Polarized Microstrip Antenna with an Air Gap for Wideband Applications

    Directory of Open Access Journals (Sweden)

    Zhongbao Wang

    2014-01-01

    Full Text Available A computer-aided design model based on the artificial neural network (ANN is proposed to directly obtain patch physical dimensions of the single-feed corner-truncated circularly polarized microstrip antenna (CPMA with an air gap for wideband applications. To take account of the effect of the air gap, an equivalent relative permittivity is introduced and adopted to calculate the resonant frequency and Q-factor of square microstrip antennas for obtaining the training data sets. ANN architectures using multilayered perceptrons (MLPs and radial basis function networks (RBFNs are compared. Also, six learning algorithms are used to train the MLPs for comparison. It is found that MLPs trained with the Levenberg-Marquardt (LM algorithm are better than RBFNs for the synthesis of the CPMA. An accurate model is achieved by using an MLP with three hidden layers. The model is validated by the electromagnetic simulation and measurements. It is enormously useful to antenna engineers for facilitating the design of the single-feed CPMA with an air gap.

  17. 极化敏感阵列的DOA及极化参数降维估计算法%Dimension-reduction for DOA and polarization estimation based on polarization sensitive array

    Institute of Scientific and Technical Information of China (English)

    曾富红; 曲志昱; 司伟建

    2017-01-01

    为解决极化MUSIC算法运算量大的问题,提出了一种适用于极化敏感阵列的秩亏损MUSIC算法.在极化MUSIC算法的基础上,通过运用矩阵秩亏损原理将谱函数进行降维优化成只与空域参数相关的二维谱函数,大大降低了谱峰搜索过程中的运算量,同时保证了波达方向(DOA)估计精度.在获得入射信号的DOA之后,通过公式可直接计算得到入射信号的极化参数,具有较低的运算量.通过仿真实验可以验证秩亏损MUSIC算法存在着较高的估计精度,并通过将其与极化MUSIC算法的计算复杂度进行对比,可以发现秩亏损MUSIC算法具有较好的实时性,在入射信号相同并含有极化信息的条件下,秩亏损MUSIC算法的计算复杂度相较于极化MUSIC算法降低了104数量级.%To solve the problem that polarization MUSIC algorithm has large computational complexity, a rank loss MUSIC algorithm suitable for polarization sensitive array was proposed.On the basis of polarization MUSIC algorithm, using the principle of matrix rank loss to reduce the dimensionality of the spectral function to two-dimensional spectral function related to the airspace parameters, the computation significantly was decreased but also guarantees the direction of arrival(DOA) estimation accuracy.After getting the DOA of the incident signal, the polarization parameters can be directly calculated by formula which has low computational complexity.Simulation results show that the proposed algorithm has high estimation precision.The proposed algorithm has better real-time performance compared with that polarization MUSIC algorithm.

  18. Global change effects on the long-term feeding ecology and contaminant exposures of East Greenland polar bears.

    Science.gov (United States)

    McKinney, Melissa A; Iverson, Sara J; Fisk, Aaron T; Sonne, Christian; Rigét, Frank F; Letcher, Robert J; Arts, Michael T; Born, Erik W; Rosing-Asvid, Aqqalu; Dietz, Rune

    2013-08-01

    Rapid climate changes are occurring in the Arctic, with substantial repercussions for arctic ecosystems. It is challenging to assess ecosystem changes in remote polar environments, but one successful approach has entailed monitoring the diets of upper trophic level consumers. Quantitative fatty acid signature analysis (QFASA) and fatty acid carbon isotope (δ(13) C-FA) patterns were used to assess diets of East Greenland (EG) polar bears (Ursus maritimus) (n = 310) over the past three decades. QFASA-generated diet estimates indicated that, on average, EG bears mainly consumed arctic ringed seals (47.5 ± 2.1%), migratory subarctic harp (30.6 ± 1.5%) and hooded (16.7 ± 1.3%) seals and rarely, if ever, consumed bearded seals, narwhals or walruses. Ringed seal consumption declined by 14%/decade over 28 years (90.1 ± 2.5% in 1984 to 33.9 ± 11.1% in 2011). Hooded seal consumption increased by 9.5%/decade (0.0 ± 0.0% in 1984 to 25.9 ± 9.1% in 2011). This increase may include harp seal, since hooded and harp seal FA signatures were not as well differentiated relative to other prey species. Declining δ(13) C-FA ratios supported shifts from more nearshore/benthic/ice-associated prey to more offshore/pelagic/open-water-associated prey, consistent with diet estimates. Increased hooded seal and decreased ringed seal consumption occurred during years when the North Atlantic Oscillation (NAO) was lower. Thus, periods with warmer temperatures and less sea ice were associated with more subarctic and less arctic seal species consumption. These changes in the relative abundance, accessibility, or distribution of arctic and subarctic marine mammals may have health consequences for EG polar bears. For example, the diet change resulted in consistently slower temporal declines in adipose levels of legacy persistent organic pollutants, as the subarctic seals have higher contaminant burdens than arctic seals. Overall, considerable changes are occurring in the EG

  19. Observation of layered antiferromagnetism in self-assembled parallel NiSi nanowire arrays on Si(110) by spin-polarized scanning tunneling spectromicroscopy

    Science.gov (United States)

    Hong, Ie-Hong; Hsu, Hsin-Zan

    2018-03-01

    The layered antiferromagnetism of parallel nanowire (NW) arrays self-assembled on Si(110) have been observed at room temperature by direct imaging of both the topographies and magnetic domains using spin-polarized scanning tunneling microscopy/spectroscopy (SP-STM/STS). The topographic STM images reveal that the self-assembled unidirectional and parallel NiSi NWs grow into the Si(110) substrate along the [\\bar{1}10] direction (i.e. the endotaxial growth) and exhibit multiple-layer growth. The spatially-resolved SP-STS maps show that these parallel NiSi NWs of different heights produce two opposite magnetic domains, depending on the heights of either even or odd layers in the layer stack of the NiSi NWs. This layer-wise antiferromagnetic structure can be attributed to an antiferromagnetic interlayer exchange coupling between the adjacent layers in the multiple-layer NiSi NW with a B2 (CsCl-type) crystal structure. Such an endotaxial heterostructure of parallel magnetic NiSi NW arrays with a layered antiferromagnetic ordering in Si(110) provides a new and important perspective for the development of novel Si-based spintronic nanodevices.

  20. Fabrication of Feedhorn-Coupled Transition Edge Sensor Arrays for Measurement of the Cosmic Microwave Background Polarization

    Science.gov (United States)

    Denis, Kevin L.; Aamir, A.; Bennett, C. L.; Chang, M. P.; Chuss, D. T.; Colazo, F. A.; Costen, N.; Essinger-Hileman, T.; Hu, R.; Marriage, T.; hide

    2015-01-01

    Characterization of the minute cosmic microwave background polarization signature requires multi-frequency high-throughput precision instrument systems. We have previously described the detector fabrication of a 40 GHz focal plane and now describe the fabrication of the detector modules for measurement of the CMB at 90GHz. The 74-TES based bolometers in each module are coupled to a niobium based planar orthomode transducer with integrated band defining filters implemented in microstrip transmission line. A single crystal silicon dielectric substrate serves as microstrip dielectric and as a thermal link between the membrane isolated MoAu TES operating at 150mK and the heat bath. A short silicon leg between the heat bath and the TES bolometer is designed for ballistic phonon transport and provides improved process control and uniformity of thermal conductance in the presence of phonon scattering on roughened surfaces. Micro-machined structures are used to realize the orthomode transducer backshort, provide out of band signal rejection, and a silicon photonic choke for feedhorn coupling are described. The backshort, choke wafer, and detector wafer are indium bump bonded to create a single 37-element dual-polarization detector module. Fourteen such hexagonally shaped modules each 90 mm in size comprise two focal planes. These, along with the recently delivered 40GHz focal plane, will survey a large fraction of the sky as part of the Johns Hopkins University led ground based CLASS (Cosmology Large Angular Scale Surveyor) telescope.

  1. Location and wavefield attributes of long-period signals at Villarrica volcano (Chile) determined by array and polarization-moveout analysis

    Science.gov (United States)

    Lehr, Johanna; Thorwart, Martin; Rabbel, Wolfgang

    2016-04-01

    Villarrica Volcano is the most active volcano in Chile whose latest eruption occurred in March 2015. Increasing the knowledge on its processes, structure and behavior is thus crucial to an effective monitoring and hazard assessment. In this context, long-period volcanic signals (LP) are considered to be a key to the understanding of fluid dynamics and volcanic plumbing systems, accessible by seismological observations. However, standard seismological location tools usually fail due to the emergent onset of the signal and its serious distortion caused by attenuation and scattering in a complex geology. Therefore, alternative methods are needed. In March 2012, a dense seismic network was installed at Villarrica for two weeks with 50 stations covering the volcanic edifice including 6 subarrays. About 400 LP events were identified. LP-events recorded on crater stations look similar to typical earthquakes arrivals with distinguishable P- and S-wave onsets indicating a source near the crater. But with increasing source distance waveforms gradually change into typical LP-events. To investigate how to locate these LP-events we tested two approaches at the basis of a show-case event. In a first trial, records of the subarrays were used to determine backazimuths and slowness by beamforming in the time domain. The analysis was performed in a moving window, using semblance to measure the beam quality. The epicenter was derived by intersecting azimuthal rays. It locates ca. 1 km southeast of the summit crater. Slownesses range from 0.5 s/km up to 2.0 s/km. At frequencies above 2 Hz, additional maxima appear in the semblance distribution of near-summit arrays which can be interpreted as side-scattered signals. Since the crossing points of the backazimuth rays showed some scattering we tested polarization analysis (applied to the subset of 3-component stations) as an alternative location method. Although the direct interpretation of the backazimuths was unreliable, we identified

  2. High Performance Circularly Polarized Microstrip Antenna

    Science.gov (United States)

    Bondyopadhyay, Probir K. (Inventor)

    1997-01-01

    A microstrip antenna for radiating circularly polarized electromagnetic waves comprising a cluster array of at least four microstrip radiator elements, each of which is provided with dual orthogonal coplanar feeds in phase quadrature relation achieved by connection to an asymmetric T-junction power divider impedance notched at resonance. The dual fed circularly polarized reference element is positioned with its axis at a 45 deg angle with respect to the unit cell axis. The other three dual fed elements in the unit cell are positioned and fed with a coplanar feed structure with sequential rotation and phasing to enhance the axial ratio and impedance matching performance over a wide bandwidth. The centers of the radiator elements are disposed at the corners of a square with each side of a length d in the range of 0.7 to 0.9 times the free space wavelength of the antenna radiation and the radiator elements reside in a square unit cell area of sides equal to 2d and thereby permit the array to be used as a phased array antenna for electronic scanning and is realizable in a high temperature superconducting thin film material for high efficiency.

  3. High-efficiency and multi-frequency polarization converters based on graphene metasurface with twisting double L-shaped unit structure array

    Science.gov (United States)

    Chen, Ming; Xiao, Xiaofei; Chang, Linzi; Wang, Congyun; Zhao, Deping

    2017-07-01

    In this work, a high-efficiency and tunable dual-frequency reflective polarization converter composed of graphene metasurface with twisting double L-shaped unit is firstly realized. Numerical results demonstrate that the device can convert a linearly polarized wave to its cross-polarized wave, and meantime it can also convert to a circularly polarized wave. Subsequently, one thickness of 500 nm SiO2 layer sandwiched by two graphene metasurfaces with similar pattern is stacked on the top of the two-layered structure, a four-frequency efficient reflective polarization converters is realized. Above all, those working frequencies can also be dynamically tuned within a large frequency range by adjusting the Fermi energy of the graphene, without reoptimizing and refabricating the nanostructures, which paves a novel way toward developing a controllable polarization converter for mid-infrared applications.

  4. Photovoltaic cell array

    Science.gov (United States)

    Eliason, J. T. (Inventor)

    1976-01-01

    A photovoltaic cell array consisting of parallel columns of silicon filaments is described. Each fiber is doped to produce an inner region of one polarity type and an outer region of an opposite polarity type to thereby form a continuous radial semi conductor junction. Spaced rows of electrical contacts alternately connect to the inner and outer regions to provide a plurality of electrical outputs which may be combined in parallel or in series.

  5. Timed arrays wideband and time varying antenna arrays

    CERN Document Server

    Haupt, Randy L

    2015-01-01

    Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

  6. Neutral Hydrogen Structures Trace Dust Polarization Angle: Implications for Cosmic Microwave Background Foregrounds.

    Science.gov (United States)

    Clark, S E; Hill, J Colin; Peek, J E G; Putman, M E; Babler, B L

    2015-12-11

    Using high-resolution data from the Galactic Arecibo L-Band Feed Array HI (GALFA-Hi) survey, we show that linear structure in Galactic neutral hydrogen (Hi) correlates with the magnetic field orientation implied by Planck 353 GHz polarized dust emission. The structure of the neutral interstellar medium is more tightly coupled to the magnetic field than previously known. At high Galactic latitudes, where the Planck data are noise dominated, the Hi data provide an independent constraint on the Galactic magnetic field orientation, and hence the local dust polarization angle. We detect strong cross-correlations between template maps constructed from estimates of dust intensity combined with either Hi-derived angles, starlight polarization angles, or Planck 353 GHz angles. The Hi data thus provide a new tool in the search for inflationary gravitational wave B-mode polarization in the cosmic microwave background, which is currently limited by dust foreground contamination.

  7. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  8. Transcriptional profiling of root-knot nematode induced feeding sites in cowpea (Vigna unguiculata L. Walp. using a soybean genome array

    Directory of Open Access Journals (Sweden)

    Das Sayan

    2010-08-01

    Full Text Available Abstract Background The locus Rk confers resistance against several species of root-knot nematodes (Meloidogyne spp., RKN in cowpea (Vigna unguiculata. Based on histological and reactive oxygen species (ROS profiles, Rk confers a delayed but strong resistance mechanism without a hypersensitive reaction-mediated cell death process, which allows nematode development but blocks reproduction. Results Responses to M. incognita infection in roots of resistant genotype CB46 and a susceptible near-isogenic line (null-Rk were investigated using a soybean Affymetrix GeneChip expression array at 3 and 9 days post-inoculation (dpi. At 9 dpi 552 genes were differentially expressed in incompatible interactions (infected resistant tissue compared with non-infected resistant tissue and 1,060 genes were differentially expressed in compatible interactions (infected susceptible tissue compared with non-infected susceptible tissue. At 3 dpi the differentially expressed genes were 746 for the incompatible and 623 for the compatible interactions. When expression between infected resistant and susceptible genotypes was compared, 638 and 197 genes were differentially expressed at 9 and 3 dpi, respectively. Conclusions In comparing the differentially expressed genes in response to nematode infection, a greater number and proportion of genes were down-regulated in the resistant than in the susceptible genotype, whereas more genes were up-regulated in the susceptible than in the resistant genotype. Gene ontology based functional categorization revealed that the typical defense response was partially suppressed in resistant roots, even at 9 dpi, allowing nematode juvenile development. Differences in ROS concentrations, induction of toxins and other defense related genes seem to play a role in this unique resistance mechanism.

  9. Bias-polarity-dependent UV/visible transferable electroluminescence from ZnO nanorod array LED with graphene oxide electrode supporting layer

    Science.gov (United States)

    Liu, Weizhen; Wang, Wei; Xu, Haiyang; Li, Xinghua; Yang, Liu; Ma, Jiangang; Liu, Yichun

    2015-09-01

    A simple top electrode preparation process, employing continuous graphene oxide films as electrode supporting layers, was adopted to fabricate a ZnO nanorod array/p-GaN heterojunction LED. The achieved LED demonstrated different electroluminescence behaviors under forward and reverse biases: a yellow-red emission band was observed under forward bias, whereas a blue-UV emission peak was obtained under reverse bias. Electroluminescence spectra under different currents and temperatures, as well as heterojunction energy-band alignments, reveal that the yellow-red emission under forward bias originates from recombinations related to heterointerface defects, whereas the blue-UV electroluminescence under reverse bias is ascribed to transitions from near-band-edge and Mg-acceptor levels in p-GaN.

  10. Feeding Tubes

    Science.gov (United States)

    ... feeding therapies have been exhausted. Please review product brand and method of placement carefully with your physician ... Total Parenteral Nutrition. Resources: Oley Foundation Feeding Tube Awareness Foundation Children’s Medical Nutrition Alliance APFED’s Educational Webinar ...

  11. 极化敏感L型阵模值约束的多参数联合估计%Multi-Parameters Estimation for L-Shaped Polarization Sensitive Array Using the Modulus Constraint

    Institute of Scientific and Technical Information of China (English)

    张远芳; 周正; 李会勇

    2016-01-01

    对于极化敏感 L 型阵列的多参数联合估计问题,采用传统的多重信号分类(MUSIC)算法所需计算量大,采用旋转不变子空间(ESPRIT)算法需要考虑参数配对问题。提出了模值约束下的求根多重信号分类(root-MUSIC)算法,首先利用 L 型阵列中两个相互垂直的线阵构造两子阵接收数据的自相关函数,采用 root-MUSIC 算法进行波达方向角(DOA)估计,然后根据模值约束条件构造代价函数,通过闭合式解得到极化参数估计。该算法与传统 MUSIC 算法相比,大大减少了计算量,同时能够实现参数自动配对,避免了 ESPRIT 算法的不足。计算机仿真结果表明,该算法的角度估计性能与传统 MUSIC 算法接近,优于ESPRIT 算法,且算法收敛速度快。%A large amount of computation is required when using the traditional MUSIC algorithm and the parameter matching problem should be considered when using ESPRIT algorithm for multi-parameters estimation of L-shaped polarization sensitive array.A root-MUSIC algorithm with modulus constraint is pro-posed.This algorithm estimates the DOA and polarization parameters in two separate steps.In step one,the autocorrelation function of the received data from two mutually vertical linear arrays is constructed,and DOA parameter is estimated by root-MUSIC algorithm;in step two,the cost function is constructed according to constraint condition and polarization parameters are obtained with closed-form formulas.Compared with the traditional MUSIC algorithm,the proposed algorithm greatly reduces the amount of calculation.It can realize automatic matching parameters at the same time,which avoids the deficiency of the ESPRIT algorithm.The computer simulation results show that the angle estimation performance of the proposed algorithm is close to traditional MUSIC algorithm,and is better than ESPRIT algorithm.Furthermore,the proposed algorithm has fast convergence speed.

  12. HERA Broadband Feed Design for Low-Frequency Radio Astronomy

    Science.gov (United States)

    Garza, Sierra; Trung, Vincent; Ewall-Wice, Aaron Michael; Li, Jianshu; Hewitt, Jacqueline; Riley, Daniel; Bradley, Richard F.; Makhija, Krishna

    2018-01-01

    As part of the Hydrogen Epoch of Reionization Array (HERA) project, we are designing a broadband low-frequency radio feed to extend the bandwidth from 100-200 MHz to 50-220 MHz. By extending the lower-limit to 50 MHz, we hope to detect the signatures of the first black holes heating the hydrogen gas in the intergalactic medium.The isolation of a very faint signal from vastly brighter foregrounds sets strict requirements on antenna spectral smoothness, polarization purity, forward gain, and internal reflections. We are currently working to meet these requirements with a broad-band sinuous antenna feed suspended over the 14-m parabolic HERA dish, using a combination of measurements and simulations to verify the performance of our design.A sinuous feed has been designed and simulated with Computer Simulation Technology (CST) software. We will present the construction of a prototype sinuous antenna and measurements of its reflection coefficient, S11, including laboratory characterization of baluns. Our measurements agree well with the CST simulations of the antenna’s performance, giving us confidence in our ability to model the feed and ensure that it meets the requirements of a 21cm cosmology measurement.

  13. Analysis and synthesis of (SAR) waveguide phased array antennas

    Science.gov (United States)

    Visser, H. J.

    1994-02-01

    This report describes work performed due to ESA contract No. 101 34/93/NL/PB. Started is with a literature study on dual polarized waveguide radiators, resulting in the choice for the open ended square waveguide. After a thorough description of the mode matching infinite waveguide array analysis method - including finiteness effects - that forms the basis for all further described analysis and synthesis methods, the accuracy of the analysis software is validated by comparison with measurements on two realized antennas. These antennas have centered irises in the waveguide apertures and a dielectric wide angle impedance matching sheet in front of the antenna. A synthesis method, using simulated annealing and downhill simplex, is described next and different antenna designs, based on the analysis of a single element in an infinite array environment, are presented. Next, designs of subarrays are presented. Shown is the paramount importance of including the array environment in the design of a subarray. A microstrip patch waveguide exciter and subarray feeding network are discussed and the depth of the waveguide radiator is estimated. Chosen is a rectangular grid array with waveguides of 2.5 cm depth without irises and without dielectric sheet, grouped in linear 8 elements subarrays.

  14. Phased-array design for MST and ST radars

    Science.gov (United States)

    Ecklund, W. L.

    1986-01-01

    All of the existing radar systems fully dedicated to clear-air radar studies use some type of phased-array antennas. The effects of beam-steering techniques including feed networks and phase shifters; sidelobe control; ground-clutter suppression; low altitude coverage; arrays with integrated radiating elements and feed networks; analysis of coaxial-collinear antennas; use of arrays with multiple beams; and array testing and measure on structural design of the antenna are discussed.

  15. Towards helium-3 neutron polarizers

    International Nuclear Information System (INIS)

    Tasset, F.

    1995-01-01

    With a large absorption cross-section entirely due to antiparallel spin capture, polarized helium-3 is presently the most promising broad-band polarizer for thermal and epithermal neutrons. Immediate interest was raised amongst the neutron community when a dense gaseous 3 He polarizer was used for the first time in 1988, on a pulsed neutron beam at Los Alamos. With 20 W of laser power on a 30 cm long, 8.6 atm target, 40% 3 He polarization was achieved in a recent polarized electron scattering experiment at SLAC. In this technique the 3 He nuclei are polarized directly at an appropriate high pressure through spin-exchange collisions with a thick, optically pumped rubidium vapor. A different and competitive approach is being presently developed at Mainz University in collaboration with ENS Paris and now the ILL. A discharge is established in pure 3 He at low pressure producing excited metastable atoms which can be optically pumped with infra-red light. Highly effective exchange collision with the atoms remaining in the ground state quickly produces 75% polarization at 1.5 mbar. A truly non-magnetic system then compresses the polarized gas up to several bars as required. The most recent machine comprises a two-stage glass-titanium compressor. In less than 1 h it can inflate a 100 cm 3 target cell with three bars of polarized gas. The very long relaxation times (several days) now being obtained at high pressure with a special metallic coating on the glass walls, the polarized cell can be detached and inserted in the neutron beam as polarizer. We expect 50% 3 He-polarization to be reached soon, allowing such filters to compete favorably with existing Heusler-crystal polarizers at thermal and short neutron wavelengths. It must be stressed that such a system based on a 3 He polarization factory able to feed several passive, transportable, polarizers is well matched to neutron scattering needs. (orig.)

  16. PolarTrack: Optical Outside-In Device Tracking that Exploits Display Polarization

    DEFF Research Database (Denmark)

    Rädle, Roman; Jetter, Hans-Christian; Fischer, Jonathan

    2018-01-01

    PolarTrack is a novel camera-based approach to detecting and tracking mobile devices inside the capture volume. In PolarTrack, a polarization filter continuously rotates in front of an off-the-shelf color camera, which causes the displays of observed devices to periodically blink in the camera feed....... The periodic blinking results from the physical characteristics of current displays, which shine polarized light either through an LC overlay to produce images or through a polarizer to reduce light reflections on OLED displays. PolarTrack runs a simple detection algorithm on the camera feed to segment...... displays and track their locations and orientations, which makes PolarTrack particularly suitable as a tracking system for cross-device interaction with mobile devices. Our evaluation of PolarTrack's tracking quality and comparison with state-of-the-art camera-based multi-device tracking showed a better...

  17. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

  18. Array capabilities and future arrays

    International Nuclear Information System (INIS)

    Radford, D.

    1993-01-01

    Early results from the new third-generation instruments GAMMASPHERE and EUROGAM are confirming the expectation that such arrays will have a revolutionary effect on the field of high-spin nuclear structure. When completed, GAMMASHPERE will have a resolving power am order of magnitude greater that of the best second-generation arrays. When combined with other instruments such as particle-detector arrays and fragment mass analysers, the capabilites of the arrays for the study of more exotic nuclei will be further enhanced. In order to better understand the limitations of these instruments, and to design improved future detector systems, it is important to have some intelligible and reliable calculation for the relative resolving power of different instrument designs. The derivation of such a figure of merit will be briefly presented, and the relative sensitivities of arrays currently proposed or under construction presented. The design of TRIGAM, a new third-generation array proposed for Chalk River, will also be discussed. It is instructive to consider how far arrays of Compton-suppressed Ge detectors could be taken. For example, it will be shown that an idealised open-quote perfectclose quotes third-generation array of 1000 detectors has a sensitivity an order of magnitude higher again than that of GAMMASPHERE. Less conventional options for new arrays will also be explored

  19. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  20. Halbach arrays in precision motion control

    Energy Technology Data Exchange (ETDEWEB)

    Trumper, D.L.; Williams, M.E. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1995-02-01

    The Halbach array was developed for use as an optical element in particle accelerators. Following up on a suggestion from Klaus Halbach, the authors have investigated the utility of such arrays as the permanent magnet structure for synchronous machines in cartesian, polar, and cylindrical geometries. Their work has focused on the design of a novel Halbach array linear motor for use in a magnetic suspension stage for photolithography. This paper presents the details of the motor design and its force and power characteristics.

  1. Novel wideband microwave polarization network using a fully-reconfigurable photonic waveguide interleaver with a two-ring resonator-assisted asymmetric Mach-Zehnder structure.

    Science.gov (United States)

    Zhuang, Leimeng; Beeker, Willem; Leinse, Arne; Heideman, René; van Dijk, Paulus; Roeloffzen, Chris

    2013-02-11

    We propose and demonstrate a novel wideband microwave photonic polarization network for dual linear-polarized antennas. The polarization network is based on a waveguide-implemented fully-reconfigurable optical interleaver using a two-ring resonator-assisted asymmetric Mach-Zehnder structure. For microwave photonic signal processing, this structure is able to serve as a wideband 2 × 2 RF coupler with reconfigurable complex coefficients, and therefore can be used as a polarization network for wideband antennas. Such a device can equip the antennas with not only the polarization rotation capability for linear-polarization signals but also the capability to operate with and tune between two opposite circular polarizations. Operating together with a particular modulation scheme, the device is also able to serve for simultaneous feeding of dual-polarization signals. These photonic-implemented RF functionalities can be applied to wideband antenna systems to perform agile polarization manipulations and tracking operations. An example of such a interleaver has been realized in TriPleX waveguide technology, which was designed with a free spectral range of 20 GHz and a mask footprint of smaller than 1 × 1 cm. Using the realized device, the reconfigurable complex coefficients of the polarization network were demonstrated with a continuous bandwidth from 2 to 8 GHz and an in-band phase ripple of smaller than 5 degree. The waveguide structure of the device allows it to be further integrated with other functional building blocks of a photonic integrated circuit to realize on-chip, complex microwave photonic processors. Of particular interest, it can be included in an optical beamformer for phased array antennas, so that simultaneous wideband beam and polarization trackings can be achieved photonically. To our knowledge, this is the first-time on-chip demonstration of an integrated microwave photonic polarization network for dual linear-polarized antennas.

  2. SNP Arrays

    Directory of Open Access Journals (Sweden)

    Jari Louhelainen

    2016-10-01

    Full Text Available The papers published in this Special Issue “SNP arrays” (Single Nucleotide Polymorphism Arrays focus on several perspectives associated with arrays of this type. The range of papers vary from a case report to reviews, thereby targeting wider audiences working in this field. The research focus of SNP arrays is often human cancers but this Issue expands that focus to include areas such as rare conditions, animal breeding and bioinformatics tools. Given the limited scope, the spectrum of papers is nothing short of remarkable and even from a technical point of view these papers will contribute to the field at a general level. Three of the papers published in this Special Issue focus on the use of various SNP array approaches in the analysis of three different cancer types. Two of the papers concentrate on two very different rare conditions, applying the SNP arrays slightly differently. Finally, two other papers evaluate the use of the SNP arrays in the context of genetic analysis of livestock. The findings reported in these papers help to close gaps in the current literature and also to give guidelines for future applications of SNP arrays.

  3. Novel micromachined on-chip 10-elements wire-grid array operating at 60 GHz

    KAUST Repository

    Sallam, Mai O.

    2017-06-07

    This paper presents a new topology for a wire-grid antenna array which operates at 60 GHz. The array consists of ten λ/2 dipole radiators connected via non-radiating connectors. Both radiators and connectors are placed on top of narrow silicon walls. The antenna is fed with a coplanar microstrip lines placed at the other side of the wafer and is connected with its feeding transmission lines using through-silicon-vias. The antenna is optimized for two cases: using high- and low-resistivity silicon substrates. The former has better radiation characteristics while the later is more compatible with the driving electronic circuits. The antenna has high directivity, reasonable bandwidth and high polarization purity.

  4. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  5. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  6. electrode array

    African Journals Online (AJOL)

    PROF EKWUEME

    A geoelectric investigation employing vertical electrical soundings (VES) using the Ajayi - Makinde Two-Electrode array and the ... arrangements used in electrical D.C. resistivity survey. These include ..... Refraction Tomography to Study the.

  7. An Ultra-Wideband Millimeter-Wave Phased Array

    Science.gov (United States)

    Novak, Markus H.; Miranda, Felix A.; Volakis, John L.

    2016-01-01

    Wideband millimeter-wave arrays are of increasing importance due to their growing use in high data rate systems, including 5G communication networks. In this paper, we present a new class of ultra-wideband millimeter wave arrays that operate from nearly 20 GHz to 90 GHz. The array is based on tightly coupled dipoles. Feeding designs and fabrication challenges are presented, and a method for suppressing feed resonances is provided.

  8. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  9. Carbon nanotube fiber terahertz polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, Ahmed [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Tsentalovich, Dmitri E.; Young, Colin C. [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Heimbeck, Martin S. [Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Everitt, Henry O. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Pasquali, Matteo [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2016-04-04

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼−30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2–1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

  10. Graphene-based magnetless converter of terahertz wave polarization

    Science.gov (United States)

    Melnikova, Veronica S.; Polischuk, Olga V.; Popov, Vyacheslav V.

    2016-04-01

    The polarization conversion of terahertz radiation by the periodic array of graphene nanoribbons located at the surface of a high-refractive-index dielectric substrate (terahertz prism) is studied theoretically. Giant polarization conversion at the plasmon resonance frequencies takes place without applying external DC magnetic field. It is shown that the total polarization conversion can be reached at the total internal reflection of THz wave from the periodic array of graphene nanoribbons even at room temperature.

  11. Ionic polarization

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1992-01-01

    Ferroelectricity occurs in many different kinds of materials. Many of the technologically important solids, which are ferroelectric, can be classified as ionic. Any microscopic theory of ferroelectricity must contain a description of local polarization forces. We have collaborated in the development of a theory of ionic polarization which is quite successful. Its basic assumption is that the polarization is derived from the properties of the individual ions. We have applied this theory successfully to diverse subjects as linear and nonlinear optical response, phonon dispersion, and piezoelectricity. We have developed numerical methods using the local Density approximation to calculate the multipole polarizabilities of ions when subject to various fields. We have also developed methods of calculating the nonlinear hyperpolarizability, and showed that it can be used to explain light scattering experiments. This paper elaborates on this polarization theory

  12. Polarization experiments

    International Nuclear Information System (INIS)

    Halzen, F.

    1977-02-01

    In a theoretical review of polarization experiments two important points are emphasized: (a) their versatility and their relevance to a large variety of aspects of hadron physics (tests of basic symmetries; a probe of strong interaction dynamics; a tool for hadron spectroscopy); (b) the wealth of experimental data on polarization parameters in pp and np scattering in the Regge language and in the diffraction language. (author)

  13. Filter arrays

    Science.gov (United States)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  14. Polarization measurement for internal polarized gaseous targets

    International Nuclear Information System (INIS)

    Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

    2004-01-01

    The authors present an introduction to internal polarized gaseous targets, polarization method, polarization measurement method and procedure. To get the total nuclear polarization of hydrogen atoms (including the polarization of the recombined hydrogen molecules) in the target cell, authors have measured the parameters relating to atomic polarization and polarized hydrogen atoms and molecules. The total polarization of the target during our measurement is P T =0.853 ± 0.036. (authors)

  15. Airborne electronically steerable phased array

    Science.gov (United States)

    1972-01-01

    The results are presented of the second stage of a program for the design and development of a phased array capable of simultaneous and separate transmission and reception of radio frequency signals at S-band frequencies. The design goals of this stage were the development of three major areas of interest required for the final prototype model. These areas are the construction and testing of the low-weight, full-scale 128-element array of antenna elements, the development of the RF manifold feed system, and the construction and testing of a working module containing diplexer and transmit and receive circuits.

  16. Design and simulation of a novel circularly polarized antenna with polarization reconfigurable characteristics

    Directory of Open Access Journals (Sweden)

    Zhang Hai

    2016-01-01

    Full Text Available A novel circularly polarized antenna with polarization reconfigurable characteristics was designed using co-simulation of Ansoft HFSS and Designer software. It consists of a dual-polarized antenna and phase switching network which act as the feed network for the dual-polarized antenna. The phase switching network was designed based on a Wilkinson power divider, where the output port was connected with SPDT to form a switching network. By controlling the SPDT state-off / on, the phase difference of the two ports could be alternated, which generated the orthogonal modes between the two ports of dual-polarized antenna. So that Left-hand circular polarization (LHCP and Right-hand circular polarization (RHCP could be achieved. The simulation shown that reflection coefficient was less than -12 dB and the axial ratio was below 3 dB between 1.8 GHz and 2.4 GHz with polarization reconfigurable characteristics.

  17. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

    Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

  18. Reduction of the In-Band RCS of Microstrip Patch Antenna by Using Offset Feeding Technique

    Directory of Open Access Journals (Sweden)

    Weiwei Xu

    2014-01-01

    Full Text Available This paper presents a method for implementing a low in-band scattering design for microstrip patch antennas based on the analysis of structural mode scattering and radiation characteristics. The antenna structure is first designed to have the lowest structural mode scattering in a desired frequency band. The operating frequency band of the antenna is then changed to coincide with that of the lowest structural mode scattering by adjusting the feed position on the antenna (offset feeding to achieve an antenna with low in-band radar cross section (RCS. In order to reduce the level of cross polarization of the antenna caused by offset feeding, symmetry feeding structures for both single patch antennas and two-patch arrays are proposed. Examples that show the efficiency of the method are given, and the results illustrate that the in-band RCS of the proposed antennas can be reduced by as much as 17 dBsm for plane waves impinging from the normal direction compared to patch antennas fed by conventional methods.

  19. Degree of polarization and source counts of faint radio sources from Stacking Polarized intensity

    International Nuclear Information System (INIS)

    Stil, J. M.; George, S. J.; Keller, B. W.; Taylor, A. R.

    2014-01-01

    We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of a class of radio sources, but also avoids a detection threshold in polarized intensity, and therefore an arbitrary exclusion of sources with a low percentage of polarization. Correction for polarization bias is done through a Monte Carlo analysis and tested on a simulated survey. We show that the nonlinear relation between the real polarized signal and the detected signal requires knowledge of the shape of the distribution of fractional polarization, which we constrain using the ratio of the upper quartile to the lower quartile of the distribution of stacked polarized intensities. Stacking polarized intensity for NRAO VLA Sky Survey (NVSS) sources down to the detection limit in Stokes I, we find a gradual increase in median fractional polarization that is consistent with a trend that was noticed before for bright NVSS sources, but is much more gradual than found by previous deep surveys of radio polarization. Consequently, the polarized radio source counts derived from our stacking experiment predict fewer polarized radio sources for future surveys with the Square Kilometre Array and its pathfinders.

  20. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    The configuration of a tomographic array in which the object can rotate about its axis is described. The X-ray detector is a cylindrical screen perpendicular to the axis of rotation. The X-ray source has a line-shaped focus coinciding with the axis of rotation. The beam is fan-shaped with one side of this fan lying along the axis of rotation. The detector screen is placed inside an X-ray image multiplier tube

  1. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    A tomographic array with the following characteristics is described. An X-ray screen serving as detector is placed before a photomultiplier tube which itself is placed in front of a television camera connected to a set of image processors. The detector is concave towards the source and is replacable. Different images of the object are obtained simultaneously. Optical fibers and lenses are used for transmission within the system

  2. Polarization study

    International Nuclear Information System (INIS)

    Nurushev, S.B.

    1989-01-01

    Brief review is presented of the high energy polarization study including experimental data and the theoretical descriptions. The mostimportant proposals at the biggest accelerators and the crucial technical developments are also listed which may become a main-line of spin physics. 35 refs.; 10 figs.; 4 tabs

  3. Polar Stratigraphy

    Science.gov (United States)

    1999-01-01

    These three images were taken on three different orbits over the north polar cap in April 1999. Each shows a different part of the same ice-free trough. The left and right images are separated by a distance of more than 100 kilometers (62 miles). Note the similar layers in each image.

  4. Advanced research capabilities for neutron science and technology: Neutron polarizers for neutron scattering

    International Nuclear Information System (INIS)

    Penttila, S.I.; Fitzsimmons, M.R.; Delheij, P.J.

    1998-01-01

    The authors describe work on the development of polarized gaseous 3 He cells, which are intended for use as neutron polarizers. Laser diode arrays polarize Rb vapor in a sample cell and the 3 He is polarized via collisions. They describe development and tests of such a system at LANSCE

  5. The in-capillary DPPH-capillary electrophoresis-the diode array detector combined with reversed-electrode polarity stacking mode for screening and quantifying major antioxidants in Cuscuta chinensis Lam.

    Science.gov (United States)

    Liu, Jiao; Tian, Ji; Li, Jin; Azietaku, John Teye; Zhang, Bo-Li; Gao, Xiu-Mei; Chang, Yan-Xu

    2016-07-01

    An in-capillary 2, 2-diphenyl-1-picrylhydrazyl (DPPH)-CE-the DAD (in-capillary DPPH-CE-DAD) combined with reversed-electrode polarity stacking mode has been developed to screen and quantify the active antioxidant components of Cuscuta chinensis Lam. The operation parameters were optimized with regard to the pH and concentration of buffer solution, SDS, β-CDs, organic modifier, as well as separation voltage and temperature. Six antioxidants including chlorogenic acid, p-coumaric acid, rutin, hyperin, isoquercitrin, and astragalin were screened and the total antioxidant activity of the complex matrix was successfully evaluated based on the decreased peak area of DPPH by the established DPPH-CE-DAD method. Sensitivity was enhanced under reversed-electrode polarity stacking mode and 10- to 31-fold of magnitude improvement in detection sensitivity for each analyte was attained. The results demonstrated that the newly established in-capillary DPPH-CE-DAD method combined with reversed-electrode polarity stacking mode could integrate sample concentration, the oxidizing reaction, separation, and detection into one capillary to fully automate the system. It was considered a suitable technique for the separation, screening, and determination of trace antioxidants in natural products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Feed network and electromagnetic radiation source

    Science.gov (United States)

    Ardavan, Arzhang; Singleton, John; Linehan, Kevin E.; Ardavan, Houshang; Schmidt-Zwiefel, Andrea Caroline

    2017-01-17

    An antenna may include a volume polarization current radiator and a feed network. The volume polarization current radiator, includes a dielectric solid (such as a dielectric strip), and a plurality of closely-spaced excitation elements (24), each excitation element (24) being configured to induce a volume polarization current distribution in the dielectric solid proximate to the excitation element when a voltage is applied to the excitation element. The feed network is coupled to the volume polarization current radiator. The feed network also includes a plurality of passive power divider elements (32) and a plurality of passive delay elements (d1-d6) coupling the first port (30) and the plurality of second ports (108, 109, 164), the plurality of power divider elements (32) and the plurality of phase delay elements (d1-d6) being configured such that a radio-frequency signal that is applied to the first port (30) experiences a progressive change of phase as it is coupled to the plurality of second ports (108, 109, 164) so as to cause the volume polarization current distribution to propagate along the dielectric solid.

  7. Superconducting polarizing magnet for a movable polarized target

    International Nuclear Information System (INIS)

    Anishchenko, N.G.; Bartenev, V.D.; Blinov, N.A.

    1998-01-01

    The superconducting polarizing magnet was constructed for the JINR (Dubna) movable polarized target (MPT) with working volume 200 mm long and 30 mm in diameter. The magnet provides a polarizing magnetic field up to 6 T in the centre with the uniformity of 4.5 x 10 -4 in the working volume of the target. The magnet contains a main solenoidal winding 558 mm long and 206/144 mm in diameters, and compensating and correcting winding placed at its ends. The windings are made of a NbTi wire, impregnated with the epoxy resin and placed in the horizontal cryostat. The diameter of the 'warm' aperture of the magnet cryostat is 96 mm. The design and technology of the magnet winding are described. Results of the magnetic field map measurements, using a NMR-magnetometer are given. A similar magnet constructed at DAPNIA, CEA/Saclay (France), represented a model for the present development. The MPT array is installed in the beam line of polarized neutrons produced by break-up of polarized deuterons extracted from the synchrophasotron of the Laboratory of High Energies (LHE), JINR (Dubna)

  8. Feeding Your Baby

    Medline Plus

    Full Text Available ... care Is it safe? Labor & birth Postpartum care Baby Caring for your baby Feeding your baby Family ... community Home > Baby > Feeding your baby Feeding your baby E-mail to a friend Please fill in ...

  9. Feeding Your Baby

    Medline Plus

    Full Text Available ... our online community Home > Baby > Feeding your baby Feeding your baby E-mail to a friend Please ... been added to your dashboard . Time to eat! Feeding your baby helps her grow healthy and strong. ...

  10. Breastfeeding vs. Formula Feeding

    Science.gov (United States)

    ... for Educators Search English Español Breastfeeding vs. Formula Feeding KidsHealth / For Parents / Breastfeeding vs. Formula Feeding What's ... work with a lactation specialist. All About Formula Feeding Commercially prepared infant formulas are a nutritious alternative ...

  11. Feeding tube insertion - gastrostomy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002937.htm Feeding tube insertion - gastrostomy To use the sharing features on this page, please enable JavaScript. A gastrostomy feeding tube insertion is the placement of a feeding ...

  12. Animal Feeding Operations

    Science.gov (United States)

    ... type=”submit” value=”Submit” /> Healthy Water Home Animal Feeding Operations Recommend on Facebook Tweet Share Compartir ... of Concentrated Animal Feeding Operations (CAFOs) What are Animal Feeding Operations (AFOs)? According to the United States ...

  13. Polar Polygons

    Science.gov (United States)

    2005-01-01

    18 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-outlined polygons on a frost-covered surface in the south polar region of Mars. In summer, this surface would not be bright and the polygons would not have dark outlines--these are a product of the presence of seasonal frost. Location near: 77.2oS, 204.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  14. Gold Photoluminescence: Wavelength and Polarization Engineering

    DEFF Research Database (Denmark)

    Andersen, Sebastian Kim Hjælm; Pors, Anders Lambertus; Bozhevolnyi, Sergey I.

    2015-01-01

    We demonstrate engineering of the spectral content and polarization of photoluminescence (PL) from arrayed gold nanoparticles atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances (GSPRs). Choice of shapes...... and dimensions of gold nanoparticles influences the GSPR wavelength and polarization characteristics, thereby allowing us to enhance and spectrally mold the plasmon-assisted PL while simultaneously controlling its polarization. In order to understand the underlying physics behind the plasmon-enhanced PL, we...

  15. Wideband Monolithic Tile for Reconfigurable Phased Arrays

    Science.gov (United States)

    2017-03-01

    interference and jamming. Previous reconfigurable architectures [1] were limited in bandwidth and performance by the use of discrete SMT components with...Settings Figure 7 shows the feed point and segment activation with control settings optimized for Gain, Horizontal Polarization, Steered at Phi = 15°, 6

  16. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  17. The measurement of echodirection in a phased-array radar

    NARCIS (Netherlands)

    Rijsdijk, F.B.; Spek, G.A. van der

    1978-01-01

    For a planar-array antenna with a monopulse feed horn, this study describes a simple algorithm for the determination of the direction of target echoes. Antenna pattern measurements of the array indicate that the direction sines of a received wavefront can be independently obtained with one simple

  18. Characterization of phenolic and other polar compounds in peel and flesh of pink guava (Psidium guajava L. cv. 'Criolla') by ultra-high performance liquid chromatography with diode array and mass spectrometric detection.

    Science.gov (United States)

    Rojas-Garbanzo, Carolina; Zimmermann, Benno F; Schulze-Kaysers, Nadine; Schieber, Andreas

    2017-10-01

    Pink guava (Psidium guajava L.) is a highly consumed fruit in tropical countries. Despite of interesting research on health effects of this fruit, investigations into the profile of secondary plant metabolites are scarce. In this study, the phenolic compounds in the peel and flesh of pink guava were characterized by ultra-high performance liquid chromatography with diode array and mass spectrometric detection. Sixty phenolic compounds were characterized by MS 2 and classified as ellagitannins, flavones, flavonols, flavanols, proanthocyanidins, dihydrochalcones, and anthocyanidins, and non-flavonoids such as phenolic acid derivatives, stilbenes, acetophenones, and benzophenones. Forty-two polyphenols are reported for the first time in both peel and flesh, and twenty-four compounds were detected for the first time in P. guajava, e.g., phlorizin, nothofagin, astringin, chrysin-C-glucoside, valoneic acid bilactone, cinnamoyl-glucoside, and two dimethoxycinnamoyl-hexosides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Polarized secondary radioactive beams

    International Nuclear Information System (INIS)

    Zaika, N.I.

    1992-01-01

    Three methods of polarized radioactive nuclei beam production: a) a method nuclear interaction of the non-polarized or polarized charged projectiles with target nuclei; b) a method of polarization of stopped reaction radioactive products in a special polarized ion source with than following acceleration; c) a polarization of radioactive nuclei circulating in a storage ring are considered. Possible life times of the radioactive ions for these methods are determined. General schemes of the polarization method realizations and depolarization problems are discussed

  20. Polar crane

    International Nuclear Information System (INIS)

    Makosinski, S.

    1981-01-01

    In many applications polar cranes have to be repeatedly positioned with high accuracy. A guidance system is disclosed which has two pairs of guides. Each guide consists of two rollers carried by a sheave rotatable mounted on the crane bridge, the rollers being locatable one on each side of a guideway, e.g. the circular track on which the bridge runs. The pairs of guides are interconnected by respective rope loops which pass around and are locked to the respective pairs of sheaves in such a manner that movement of one guide results in equal movement of the other guide in a sense to maintain the repeatability of positioning of the centre of the bridge. A hydraulically-linked guide system is also described. (author)

  1. Anomalous complete opaqueness in a sparse array of gold nanoparticle chains

    International Nuclear Information System (INIS)

    Bai Benfeng; Li Xiaowei; Vartiainen, Ismo; Lehmuskero, Anni; Turunen, Jari; Kuittinen, Markku; Vahimaa, Pasi; Kang Guoguo

    2011-01-01

    We report on an anomalous polarization-switching extinction effect in a sparse array of gold nanoparticle chains: under normal incidence of light, the array is almost transparent for one polarization; whereas it is fully opaque (with nearly zero transmittance) for the orthogonal polarization within a narrow band, even though the nanoparticles cover only a tiny fraction (say, 3.5%) of the transparent substrate surface. We reveal that the strong polarization-dependent short-range dipolar coupling and long-range radiative coupling of gold nanoparticles in this highly asymmetric array is responsible for this extraordinary effect.

  2. Constraining Polarized Foregrounds for EoR Experiments. II. Polarization Leakage Simulations in the Avoidance Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Nunhokee, C. D.; Bernardi, G.; Foster, G.; Grobler, T. L. [Department of Physics and Electronics, Rhodes University, P.O. Box 94, Grahamstown, 6140 (South Africa); Kohn, S. A.; Aguirre, J. E.; Martinot, J. Z. E. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Thyagarajan, N. [Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287 (United States); Dillon, J. S. [Berkeley Center for Cosmological Physics, Berkeley, CA 94720 (United States); Parsons, A. R., E-mail: cnunhokee@gmail.com [Dept. of Astronomy, University of California, Berkeley, CA 94720 (United States)

    2017-10-10

    A critical challenge in the observation of the redshifted 21 cm line is its separation from bright Galactic and extragalactic foregrounds. In particular, the instrumental leakage of polarized foregrounds, which undergo significant Faraday rotation as they propagate through the interstellar medium, may harmfully contaminate the 21 cm power spectrum. We develop a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra measured with redundant arrays, extending the delay-spectrum approach presented in Parsons et al. We construct polarized sky models and propagate them through the instrument model to simulate realistic full-sky observations with the Precision Array to Probe the Epoch of Reionization. We find that the leakage due to a population of polarized point sources is expected to be higher than diffuse Galactic polarization at any k mode for a 30 m reference baseline. For the same reference baseline, a foreground-free window at k > 0.3 h Mpc{sup −1} can be defined in terms of leakage from diffuse Galactic polarization even under the most pessimistic assumptions. If measurements of polarized foreground power spectra or a model of polarized foregrounds are given, our method is able to predict the polarization leakage in actual 21 cm observations, potentially enabling its statistical subtraction from the measured 21 cm power spectrum.

  3. Adaptive ground implemented phase array

    Science.gov (United States)

    Spearing, R. E.

    1973-01-01

    The simulation of an adaptive ground implemented phased array of five antenna elements is reported for a very high frequency system design that is tolerant to the radio frequency interference environment encountered by a tracking data relay satellite. Signals originating from satellites are received by the VHF ring array and both horizontal and vertical polarizations from each of the five elements are multiplexed and transmitted down to ground station. A panel on the transmitting end of the simulation chamber contains up to 10 S-band RFI sources along with the desired signal to simulate the dynamic relationship between user and TDRS. The 10 input channels are summed, and desired and interference signals are separated and corrected until the resultant sum signal-to-interference ratio is maximized. Testing performed with this simulation equipment demonstrates good correlation between predicted and actual results.

  4. Coupling in reflector arrays

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1968-01-01

    In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present communic......In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present...

  5. Variable-delay Polarization Modulators for the CLASS Telescope

    Science.gov (United States)

    Harrington, Kathleen; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Eimer, J.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Marriage, T.; Mehrle, N.; Miller, A. D.; Miller, N.; Mirel, P.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

    2014-01-01

    The challenges of measuring faint polarized signals at microwave wavelengths have motivated the development of rapid polarization modulators. One scalable technique, called a Variable-delay Polarization Modulator (VPM), consists of a stationary wire array in front of a movable mirror. The mirror motion creates a changing phase difference between the polarization modes parallel and orthogonal to the wire array. The Cosmology Large Angular Scale Surveyor (CLASS) will use a VPM as the first optical element in a telescope array that will search for the signature of inflation through the “B-mode” pattern in the polarization of the cosmic microwave background. In the CLASS VPMs, parallel transport of the mirror is maintained by a voice-coil actuated flexure system which will translate the mirror in a repeatable manner while holding tight parallelism constraints with respect to the wire array. The wire array will use 51 μm diameter copper-plated tungsten wire with 160 μm pitch over a 60 cm clear aperture. We present the status of the construction and testing of the mirror transport mechanism and wire arrays for the CLASS VPMs.

  6. Nuclear polarization and neutrons

    International Nuclear Information System (INIS)

    Glaettli, H.

    1985-01-01

    Different possibilities for the use of polarized nuclei in thermal neutron scattering on condensed matter are reviewed. Highly polarized nuclei are the starting point for studying dipolar magnetic order. Systematic measurement of spin-dependent scattering lengths is possible on samples with polarized nuclei. Highly polarized hydrogen should help to unravel complicated structures in chemistry and biology. The use of polarized proton targets as an energy-independent neutron polarizer in the thermal and epithermal region should be considered afresh. (author)

  7. Reactively loaded arrays based on overlapping sub-arrays with flat-top radiation pattern

    NARCIS (Netherlands)

    Maximidis, R. T.; Smolders, A. B.; Toso, G.; Caratelli, D.

    2017-01-01

    The design of reactively-loaded antenna arrays featuring a pulse-shaped radiation pattern for limited scan-angle applications is presented. The use of the reactive loading allows reducing the complexity of the feeding structure, eliminating the need for complex overlapping beam-forming networks and

  8. An Electronically Controlled 8-Element Switched Beam Planar Array

    KAUST Repository

    Sharawi, Mohammad S.

    2015-02-24

    An 8-element planar antenna array with electronically controlled switchable-beam pattern is proposed. The planar antenna array consists of patch elements and operates in the 2.45 GHz ISM band. The array is integrated with a digitally controlled feed network that provides the required phases to generate 8 fixed beams covering most of the upper hemisphere of the array. Unlike typical switchable beam antenna arrays, which operate only in one plane, the proposed design is the first to provide full 3D switchable beams with simple control. Only a 3-bit digital word is required for the generation of the 8 different beams. The integrated array is designed on a 3-layer PCB on a Taconic substrate (RF60A). The total dimensions of the fabricated array are 187.1 × 261.3 × 1.3mm3.

  9. Neutron polarization in polarized 3He targets

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

    1990-01-01

    Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

  10. Tubular fluoropolymer arrays with high piezoelectric response

    Science.gov (United States)

    Zhukov, Sergey; Eder-Goy, Dagmar; Biethan, Corinna; Fedosov, Sergey; Xu, Bai-Xiang; von Seggern, Heinz

    2018-01-01

    Polymers with electrically charged internal air cavities called ferroelectrets exhibit a pronounced piezoelectric effect and are regarded as soft functional materials suitable for sensor and actuator applications. In this work, a simple method for fabricating piezoelectret arrays with open-tubular channels is introduced. A set of individual fluoroethylenepropylene (FEP) tubes is compressed between two heated metal plates. The squeezed FEP tubes are melted together at +270 °C. The resulting structure is a uniform, multi-tubular, flat array that reveals a strong piezoelectric response after a poling step. The fabricated arrays have a high ratio between piezoelectrically active and non-active areas. The optimal charging voltage and stability of the piezoelectric coefficients with pressures and frequency were experimentally investigated for two specific array structures with wall thickness of 50 and 120 μm. The array fabricated from 50 μm thick FEP tubes reveals a stable and high piezoelectric coefficient of {d}33 = 120-160 pC N-1 with a flat frequency response between 0.1 Hz and 10 kHz for pressures between 1 and 100 kPa. An increase of wall thickness to 120 μm is accompanied by a more than twofold decrease in the piezoelectric coefficient as a result of a simultaneously higher effective array stiffness and lower remanent polarization. The obtained experimental results can be used to optimize the array design with regard to the electromechanical performance.

  11. Feeding Your Baby

    Medline Plus

    Full Text Available ... for your baby Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature birth ... for your baby Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature birth ...

  12. Feeding Your Baby

    Medline Plus

    Full Text Available ... questions Email sign up Join our online community Home > Baby > Feeding your baby Feeding your baby E- ... We're working to radically improve the health care they receive. We're pioneering research to find ...

  13. Feeding Your Baby

    Medline Plus

    Full Text Available ... fitness Prenatal care Is it safe? Labor & birth Postpartum care Baby Caring for your baby Feeding your ... fitness Prenatal care Is it safe? Labor & birth Postpartum care Baby Caring for your baby Feeding your ...

  14. Feeding Your Baby

    Medline Plus

    Full Text Available ... Home > Baby > Feeding your baby Feeding your baby E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  15. Feeding tube - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007235.htm Feeding tube - infants To use the sharing features on this page, please enable JavaScript. A feeding tube is a small, soft, plastic tube placed ...

  16. Gastrostomy feeding tube - bolus

    Science.gov (United States)

    Feeding - gastrostomy tube - bolus; G-tube - bolus; Gastrostomy button - bolus; Bard Button - bolus; MIC-KEY - bolus ... KEY, 3 to 8 weeks after surgery. These feedings will help your child grow strong and healthy. ...

  17. Feeding Your Baby

    Medline Plus

    Full Text Available ... Frequently asked questions Email sign up Join our online community Home > Baby > Feeding your baby Feeding your baby E-mail to a friend Please fill in all fields. Please enter a ...

  18. Feeding Your Baby

    Medline Plus

    Full Text Available ... Frequently asked questions Email sign up Join our online community March for Babies Nacersano Share Your Story ... Frequently asked questions Email sign up Join our online community Home > Baby > Feeding your baby Feeding your ...

  19. Three-dimensional vectorial multifocal arrays created by pseudo-period encoding

    Science.gov (United States)

    Zeng, Tingting; Chang, Chenliang; Chen, Zhaozhong; Wang, Hui-Tian; Ding, Jianping

    2018-06-01

    Multifocal arrays have been attracting considerable attention recently owing to their potential applications in parallel optical tweezers, parallel single-molecule orientation determination, parallel recording and multifocal multiphoton microscopy. However, the generation of vectorial multifocal arrays with a tailorable structure and polarization state remains a great challenge, and reports on multifocal arrays have hitherto been restricted either to scalar focal spots without polarization versatility or to regular arrays with fixed spacing. In this work, we propose a specific pseudo-period encoding technique to create three-dimensional (3D) vectorial multifocal arrays with the ability to manipulate the position, polarization state and intensity of each focal spot. We experimentally validated the flexibility of our approach in the generation of 3D vectorial multiple spots with polarization multiplicity and position tunability.

  20. Polarized electron sources

    International Nuclear Information System (INIS)

    Prepost, R.

    1994-01-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented

  1. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  2. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

    2000-01-01

    The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

  3. Circularly Polarized Microwave Antenna Element with Very Low Off-Axis Cross-Polarization

    Science.gov (United States)

    Greem. David; DuToit, Cornelis

    2013-01-01

    The goal of this work was to improve off-axis cross-polarization performance and ease of assembly of a circularly polarized microwave antenna element. To ease assembly, the initial design requirement of Hexweb support for the internal circuit part, as well as the radiating disks, was eliminated. There is a need for different plating techniques to improve soldering. It was also desirable to change the design to eliminate soldering as well as the need to use the Hexweb support. Thus, a technique was developed to build the feed without using solder, solving the lathing and soldering issue. Internal parts were strengthened by adding curvature to eliminate Hexweb support, and in the process, the new geometries of the internal parts opened the way for improving the off-axis cross-polarization performance as well. The radiating disks curvatures were increased for increased strength, but it was found that this also improved crosspolarization. Optimization of the curvatures leads to very low off-axis cross-polarization. The feed circuit was curved into a cylinder for improved strength, eliminating Hexweb support. An aperture coupling feed mechanism eliminated the need for feed pins to the disks, which would have required soldering. The aperture coupling technique also improves cross-polarization performance by effectively exciting the radiating disks very close to the antenna s central axis of symmetry. Because of the shape of the parts, it allowed for an all-aluminum design bolted together and assembled with no solder needed. The advantage of a solderless design is that the reliability is higher, with no single-point failure (solder), and no need for special plating techniques in order to solder the unit together. The shapes (curved or round) make for a more robust build without extra support materials, as well as improved offaxis cross-polarization.

  4. Breast-Feeding Twins: Making Feedings Manageable

    Science.gov (United States)

    ... Department of Health and Human Services Office on Women's Health. http://www.womenshealth.gov/publications/our-publications/breastfeeding-guide. Accessed March 11, 2015. Shelov SP, et al. Feeding your ...

  5. Feed safety in the feed supply chain

    Directory of Open Access Journals (Sweden)

    Pinotti, L.

    2011-01-01

    Full Text Available A number of issues have weakened the public's confidence in the quality and wholesomeness of foods of animal origin. As a result farmers, nutritionists, industry and governments have been forced to pay serious attention to animal feedstuff production processes, thereby acknowledging that animal feed safety is an essential prerequisite for human food safety. Concerns about these issues have produced a number of important effects including the ban on the use of processed animal proteins, the ban on the addition of most antimicrobials to farm animals diets for growth‐promotion purposes, and the implementation of feed contaminant regulations in the EU. In this context it is essential to integrate knowledge on feed safety and feed supply. Consequently, purchase of new and more economic sources of energy and protein in animal diets, which is expected to conform to adequate quality, traceability, environmental sustainability and safety standards, is an emerging issue in livestock production system.

  6. Magneto-Electric Dipole Antenna Arrays

    OpenAIRE

    Gupta, Shulabh; Jiang, Li Jun; Caloz, Christophe

    2014-01-01

    A planar magneto-electric (ME) dipole antenna array is proposed and demonstrated by both full-wave analysis and experiments. The proposed structure leverages the infinite wavelength propagation characteristic of composite right/left-handed (CRLH) transmission lines to form high-gain magnetic radiators combined with radial conventional electric radiators, where the overall structure is excited by a single differential feed. The traveling-wave type nature of the proposed ME-dipole antenna enabl...

  7. Mass Loss Rates of Fasting Polar Bears.

    Science.gov (United States)

    Pilfold, Nicholas W; Hedman, Daryll; Stirling, Ian; Derocher, Andrew E; Lunn, Nicholas J; Richardson, Evan

    2016-01-01

    Polar bears (Ursus maritimus) have adapted to an annual cyclic regime of feeding and fasting, which is extreme in seasonal sea ice regions of the Arctic. As a consequence of climate change, sea ice breakup has become earlier and the duration of the open-water period through which polar bears must rely on fat reserves has increased. To date, there is limited empirical data with which to evaluate the potential energetic capacity of polar bears to withstand longer fasts. We measured the incoming and outgoing mass of inactive polar bears (n = 142) that were temporarily detained by Manitoba Conservation and Water Stewardship during the open-water period near the town of Churchill, Manitoba, Canada, in 2009-2014. Polar bears were given access to water but not food and held for a median length of 17 d. Median mass loss rates were 1.0 kg/d, while median mass-specific loss rates were 0.5%/d, similar to other species with high adiposity and prolonged fasting capacities. Mass loss by unfed captive adult males was identical to that lost by free-ranging individuals, suggesting that terrestrial feeding contributes little to offset mass loss. The inferred metabolic rate was comparable to a basal mammalian rate, suggesting that while on land, polar bears can maintain a depressed metabolic rate to conserve energy. Finally, we estimated time to starvation for subadults and adult males for the on-land period. Results suggest that at 180 d of fasting, 56%-63% of subadults and 18%-24% of adult males in this study would die of starvation. Results corroborate previous assessments on the limits of polar bear capacity to withstand lengthening ice-free seasons and emphasize the greater sensitivity of subadults to changes in sea ice phenology.

  8. Polarized targets and beams

    International Nuclear Information System (INIS)

    Meyer, W.

    1985-01-01

    First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

  9. Fiber Laser Array

    National Research Council Canada - National Science Library

    Simpson, Thomas

    2002-01-01

    ...., field-dependent, loss within the coupled laser array. During this program, Jaycor focused on the construction and use of an experimental apparatus that can be used to investigate the coherent combination of an array of fiber lasers...

  10. Improving supplementary feeding in species conservation.

    Science.gov (United States)

    Ewen, John G; Walker, Leila; Canessa, Stefano; Groombridge, Jim J

    2015-04-01

    Supplementary feeding is often a knee-jerk reaction to population declines, and its application is not critically evaluated, leading to polarized views among managers on its usefulness. Here, we advocate a more strategic approach to supplementary feeding so that the choice to use it is clearly justified over, or in combination with, other management actions and the predicted consequences are then critically assessed following implementation. We propose combining methods from a set of specialist disciplines that will allow critical evaluation of the need, benefit, and risks of food supplementation. Through the use of nutritional ecology, population ecology, and structured decision making, conservation managers can make better choices about what and how to feed by estimating consequences on population recovery across a range of possible actions. This structured approach also informs targeted monitoring and more clearly allows supplementary feeding to be integrated in recovery plans and reduces the risk of inefficient decisions. In New Zealand, managers of the endangered Hihi (Notiomystis cincta) often rely on supplementary feeding to support reintroduced populations. On Kapiti island the reintroduced Hihi population has responded well to food supplementation, but the logistics of providing an increasing demand recently outstretched management capacity. To decide whether and how the feeding regime should be revised, managers used a structured decision making approach informed by population responses to alternative feeding regimes. The decision was made to reduce the spatial distribution of feeders and invest saved time in increasing volume of food delivered into a smaller core area. The approach used allowed a transparent and defendable management decision in regard to supplementary feeding, reflecting the multiple objectives of managers and their priorities. © 2014 The Authors. Conservation Biology published by Wiley Periodicals, Inc., on behalf of Society for

  11. Array elements for a DBS flat-plate antenna

    Science.gov (United States)

    Maddocks, M. C. D.

    1988-07-01

    The introduction of a direct broadcast by satellite (DBS) television service requires suitable receiving antennas to be available. An alternative to the parabolic dish antenna is a flat-plate antenna. The overall design of a circularly-polarized flat-plate antenna which can be mounted flat on the wall of a building has been considered in a companion Report. In this Report various types of elements are investigated and their advantages and disadvantages discussed. The most suitable element for use in a flat-plate array is identified as a linearly-polarized folded-dipole element; its performance is reported here. Linearly-polarized elements are found to perform better than circularly-polarized elements and could be used with a polarization converter to receive the circularly-polarized radiation that would be transmitted by DBS.

  12. Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry

    Science.gov (United States)

    Bock, James

    2014-01-01

    We are developing high-sensitivity millimeter-wave detector arrays for measuring the polarization of the cosmic microwave background (CMB). This development is directed to advance the technology readiness of the Inflation Probe mission in NASA's Physics of the Cosmos program. The Inflation Probe is a fourth-generation CMB satellite that will measure the polarization of the CMB to astrophysical limits, characterizing the inflationary polarization signal, mapping large-scale structure based on polarization induced by gravitational lensing, and mapping Galactic magnetic fields through measurements of polarized dust emission. The inflationary polarization signal is produced by a background of gravitational waves from the epoch of inflation, an exponential expansion of space-time in the early universe, with an amplitude that depends on the physical mechanism producing inflation. The inflationary polarization signal may be distinguished by its unique 'B-mode' vector properties from polarization from the density variations that predominantly source CMB temperature anisotropy. Mission concepts for the Inflation Probe are being developed in the US, Europe and Japan. The arrays are based on planar antennas that provide integral beam collimation, polarization analysis, and spectral band definition in a compact lithographed format that eliminates discrete fore-optics such as lenses and feedhorns. The antennas are coupled to transition-edge superconducting bolometers, read out with multiplexed SQUID current amplifiers. The superconducting sensors and readouts developed in this program share common technologies with NASA X-ray and FIR detector applications. Our program targets developments required for space observations, and we discuss our technical progress over the past two years and plans for future development. We are incorporating arrays into active sub-orbital and ground-based experiments, which advance technology readiness while producing state of the art CMB

  13. A Wideband Dual-Polarized Antenna Using Planar Quasi-Open-Sleeve Dipoles for Base Station Applications

    Directory of Open Access Journals (Sweden)

    Guan-xi Zhang

    2015-01-01

    Full Text Available A wideband dual-polarized antenna for WLAN, WiMAX, and LTE base station applications is presented in this paper. The proposed antenna consists of two pairs of orthogonal planar quasi-open-sleeve dipoles along the centerlines, a balanced feeding structure and a square ground plane. The planar quasi-open-sleeve dipole comprises a pair of bowtie-shaped planar dipoles with two parallel curve parasitic elements. The introduced parallel curve parasitic elements change the path of the current of the original bowtie-shaped planar dipoles at high frequencies and hence wideband characteristic is achieved. Two pairs of the planar quasi-open-sleeve dipoles placed orthogonally further broaden the bandwidth of the antenna with dual-polarization characteristics. The proposed antenna achieves a 10-dB return loss bandwidth from 2.32 to 4.03 GHz (53.9% bandwidth using the planar quasi-open-sleeve dipole structures. The isolation between the two ports remains more than 32 dB in the whole bandwidth. Measured results show that the proposed antenna keeps the cross-polarization under −33 dB and the front-to-back ratio better than 15 dB in the operating band. The antenna has an area of 0.3λ  × 0.3λ at 2.32 GHz making it easy to be extended to an array element.

  14. Gravitational Wave Polarizations in f (R Gravity and Scalar-Tensor Theory

    Directory of Open Access Journals (Sweden)

    Gong Yungui

    2018-01-01

    Full Text Available The detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory opens a new era to use gravitational waves to test alternative theories of gravity. We investigate the polarizations of gravitational waves in f (R gravity and Horndeski theory, both containing scalar modes. These theories predict that in addition to the familiar + and × polarizations, there are transverse breathing and longitudinal polarizations excited by the massive scalar mode and the new polarization is a single mixed state. It would be very difficult to detect the longitudinal polarization by interferometers, while pulsar timing array may be the better tool to detect the longitudinal polarization.

  15. Feedhorn-Coupled Transition-Edge Superconducting Bolometer Arrays for Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Hubmayr, J.; Austermann, J.; Beall, J.; Becker, D.; Cho, H.-M.; Datta, R.; Duff, S. M.; Grace, E.; Halverson, N.; Henderson, S. W.; hide

    2015-01-01

    NIST produces large-format, dual-polarization-sensitive detector arrays for a broad range of frequencies (30-1400 GHz). Such arrays enable a host of astrophysical measurements. Detectors optimized for cosmic microwave background observations are monolithic, polarization-sensitive arrays based on feedhorn and planar Nb antenna-coupled transition-edge superconducting (TES) bolometers. Recent designs achieve multiband, polarimetric sensing within each spatial pixel. In this proceeding, we describe our multichroic, feedhorn-coupled design; demonstrate performance at 70-380 GHz; and comment on current developments for implementation of these detector arrays in the advanced Atacama Cosmology Telescope receiver

  16. Metallic stereostructured layer: An approach for broadband polarization state manipulation

    International Nuclear Information System (INIS)

    Xiong, Xiang; Hu, Yuan-Sheng; Jiang, Shang-Chi; Hu, Yu-Hui; Fan, Ren-Hao; Ma, Guo-Bin; Shu, Da-Jun; Peng, Ru-Wen; Wang, Mu

    2014-01-01

    In this letter, we report a full-metallic broadband wave plate assembled by standing metallic L-shaped stereostructures (LSSs). We show that with an array of LSSs, high polarization conversion ratio is achieved within a broad frequency band. Moreover, by rotating the orientation of the array of LSSs, the electric components of the reflection beam in two orthogonal directions and their phase difference can be independently tuned. In this way, all the polarization states on the Poincaré sphere can be realized. As examples, the functionalities of a quarter wave plate and a half wave plate are experimentally demonstrated with both reflection spectra and focal-plane-array imaging. Our designing provides a unique approach in realizing the broadband wave plate to manipulate the polarization state of light

  17. Effect of Feed Substrate Thickness on the Bandwidth and Radiation Characteristics of an Aperture-Coupled Microstrip Antenna with a High Permittivity Feed Substrate

    Directory of Open Access Journals (Sweden)

    Jae-Hyun Kim

    2018-04-01

    Full Text Available The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA with a high permittivity (ɛr = 10 feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

  18. Biogas feed analysis

    OpenAIRE

    Song, Yuan

    2008-01-01

    Biogas production is regarded as the best energy recovery process from wet organic solid wastes (WOSW). Feed composition, storage conditions and time will influence the compositions of feed to biogas processes. In this study, apple juice from Meierienes Juice factory was used as the model substrates to mimic the liquid phase that can be extracted from fruit or juice industry WOSW. A series of batch experiments were carried out with different initial feed concentrations (0, 1, 2, 5, 10 %) of a...

  19. Breastfeeding is best feeding.

    Science.gov (United States)

    Cutting, W

    1995-02-01

    The traditional practice of breast feeding is the best means to make sure infants grow up healthy. It costs nothing. Breast milk contains antibodies and other substances which defend against disease, especially those linked to poor food hygiene and inadequate water and sanitation. In developing countries, breast fed infants are at least 14 times less likely to die from diarrhea than those who are not breast fed. Urbanization and promotion of infant formula undermine breast feeding. Even though infants up to age 4-6 months should receive only breast milk to remain as healthy as possible, infants aged less than 4-6 months often receive other milks or gruels. Attendance of health workers at delivery and their contact with mother-infant pairs after delivery are ideal opportunities to encourage mothers to breast feed. In fact, if health workers provide mothers skilled support with breast feeding, mothers are more likely to breast feed well and for a longer time. Health workers need counseling skills and firm knowledge of techniques on breast feeding and of how to master common difficulties to help mothers with breast feeding. Listening skills and confidence building skills are also needed. Good family and work place support allows women in paid employment outside the home to continue breast feeding. Breast feeding is very important in emergency situations where access to water, sanitation, food, and health care is limited (e.g., refugee camps). In these situations, health workers should especially be aware of women's ability to breast feed and to support their breast feeding. HIV can be transmitted to nursing infants from HIV infected mothers. Yet one must balance this small risk against the possibility of contracting other serious infections (e.g., diarrhea) through alternative infant feeding, particularly if there is no access to potable water and sanitation.

  20. NUCLEOTIDES IN INFANT FEEDING

    Directory of Open Access Journals (Sweden)

    L.G. Mamonova

    2007-01-01

    Full Text Available The article reviews the application of nucleotides-metabolites, playing a key role in many biological processes, for the infant feeding. The researcher provides the date on the nucleotides in the women's milk according to the lactation stages. She also analyzes the foreign experience in feeding newborns with nucleotides-containing milk formulas. The article gives a comparison of nucleotides in the adapted formulas represented in the domestic market of the given products.Key words: children, feeding, nucleotides.

  1. Scattering with polarized neutrons

    International Nuclear Information System (INIS)

    Schweizer, J.

    2007-01-01

    In the history of neutron scattering, it was shown very soon that the use of polarized neutron beams brings much more information than usual scattering with unpolarized neutrons. We shall develop here the different scattering methods that imply polarized neutrons: 1) polarized beams without polarization analysis, the flipping ratio method; 2) polarized beams with a uniaxial polarization analysis; 3) polarized beams with a spherical polarization analysis. For all these scattering methods, we shall give examples of the physical problems which can been solved by these methods, particularly in the field of magnetism: investigation of complex magnetic structures, investigation of spin or magnetization densities in metals, insulators and molecular compounds, separation of magnetic and nuclear scattering, investigation of magnetic properties of liquids and amorphous materials and even, for non magnetic material, separation between coherent and incoherent scattering. (author)

  2. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  3. Infectious waste feed system

    Science.gov (United States)

    Coulthard, E. James

    1994-01-01

    An infectious waste feed system for comminuting infectious waste and feeding the comminuted waste to a combustor automatically without the need for human intervention. The system includes a receptacle for accepting waste materials. Preferably, the receptacle includes a first and second compartment and a means for sealing the first and second compartments from the atmosphere. A shredder is disposed to comminute waste materials accepted in the receptacle to a predetermined size. A trough is disposed to receive the comminuted waste materials from the shredder. A feeding means is disposed within the trough and is movable in a first and second direction for feeding the comminuted waste materials to a combustor.

  4. Techniques in polarization physics

    International Nuclear Information System (INIS)

    Clausnitzer, G.

    1974-01-01

    A review of the current status of the technical tools necessary to perform different kinds of polarization experiments is presented, and the absolute and relative accuracy with which data can be obtained is discussed. A description of polarized targets and sources of polarized fast neutrons is included. Applications of polarization techniques to other fields is mentioned briefly. (14 figures, 3 tables, 110 references) (U.S.)

  5. Dual Polarization Multi-Frequency Antenna Array, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative approaches for broadband multi-function antennas that conserve vehicle weight and reduce drag are welcome solutions for all airborne platforms including...

  6. Gravitational Lens Time Delays Using Polarization Monitoring

    Directory of Open Access Journals (Sweden)

    Andrew Biggs

    2017-11-01

    Full Text Available Gravitational lens time delays provide a means of measuring the expansion of the Universe at high redshift (and therefore in the ‘Hubble flow’ that is independent of local calibrations. It was hoped that many of the radio lenses found in the JVAS/CLASS survey would yield time delays as these were selected to have flat spectra and are dominated by multiple compact components. However, despite extensive monitoring with the Very Large Array (VLA, time delays have only been measured for three of these systems (out of 22. We have begun a programme to reanalyse the existing VLA monitoring data with the goal of producing light curves in polarized flux and polarization position angle, either to improve delay measurements or to find delays for new sources. Here, we present preliminary results on the lens system B1600+434 which demonstrate the presence of correlated and substantial polarization variability in each image.

  7. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  8. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live...

  9. Calculation of polarization effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1983-09-01

    Basically there are two areas of accelerator applications that involve beam polarization. One is the acceleration of a polarized beam (most likely a proton beam) in a synchrotron. Another concerns polarized beams in an electron storage ring. In both areas, numerical techniques have been very useful

  10. Metal membrane with dimer slots as a universal polarizer

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Zalkovskij, Maksim; Malureanu, Radu

    2014-01-01

    In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electr......In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory...

  11. Selection of Feed Intake or Feed Efficiency

    DEFF Research Database (Denmark)

    Veerkamp, Roel F; Pryce, Jennie E; Spurlock, Diane

    2013-01-01

    . In February 2013, the co-authors discussed how information on DMI should be incorporated in the breeding decisions. The aim of this paper is to present the overall discussion and main positions taken by the group on four topics related to feed efficiency: i) breeding goal definition; ii) biological variation...

  12. Acceleration of polarized particles

    International Nuclear Information System (INIS)

    Buon, J.

    1992-05-01

    The spin kinetics of polarized beams in circular accelerators is reviewed in the case of spin-1/2 particles (electrons and protons) with emphasis on the depolarization phenomena. The acceleration of polarized proton beams in synchrotrons is described together with the cures applied to reduce depolarization, including the use of 'Siberian Snakes'. The in-situ polarization of electrons in storage rings due to synchrotron radiation is studied as well as depolarization in presence of ring imperfections. The applications of electron polarization to accurately calibrate the rings in energy and to use polarized beams in colliding-beam experiments are reviewed. (author) 76 refs., 19 figs., 1 tab

  13. Feeding Your Baby

    Medline Plus

    Full Text Available ... baby formula , find out how to choose the best one for your baby and how to make bottle-feeding safe. And then get ready for solid foods ! In This Topic Breastfeeding help Breastfeeding is best Food allergies and baby Formula feeding How to ...

  14. Feeding Your Baby

    Medline Plus

    Full Text Available ... In This Topic Breastfeeding help Breastfeeding is best Food allergies and baby Formula feeding How to breastfeed Keeping breast milk safe and healthy Problems and discomforts when breastfeeding Starting your baby on solid foods Using a breast pump Baby Feeding your baby ...

  15. Feeding Your Baby

    Medline Plus

    Full Text Available ... In This Topic Breastfeeding help Breastfeeding is best Food allergies and baby Formula feeding How to breastfeed Keeping a breastfeeding log Keeping breast milk safe and healthy Problems and discomforts when breastfeeding Starting your baby on solid foods Using a breast pump Baby Feeding your baby ...

  16. Ku-Band Traveling Wave Slot Array Using Simple Scanning Control

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2015-01-01

    This paper introduces a feeding concept aimed at simplifying the backend (phase shifters) of traditional phased arrays. As an alternative to traditional phased arrays, we employ a traveling wave array (TWA) using a single feedline whose propagation constant is controlled via a single, small mechanical movement without a need for phase shifters to enable scanning. Specifically, a dielectric plunger is positioned within a parallel plate waveguide (PPW) transmission line (TL) that feeds the TWA. By adjusting the position of the dielectric plunger within the PPW feeding the TWA, beam steering is achieved. A 20 element array is designed at 13GHz shown to give stable realized gain across the angular range of -25 deg. less than or equal to theta less than or equal to 25 deg. A proof of concept array is fabricated and measured to demonstrate and validate the concept's operation.

  17. Polarization effects. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Courant, E.

    1981-01-01

    The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.

  18. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  19. Proceedings of the workshop on polarized targets in storage rings

    International Nuclear Information System (INIS)

    Holt, R.J.

    1984-08-01

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base

  20. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  1. Josephson junction arrays

    International Nuclear Information System (INIS)

    Bindslev Hansen, J.; Lindelof, P.E.

    1985-01-01

    In this review we intend to cover recent work involving arrays of Josephson junctions. The work on such arrays falls naturally into three main areas of interest: 1. Technical applications of Josephson junction arrays for high-frequency devices. 2. Experimental studies of 2-D model systems (Kosterlitz-Thouless phase transition, commensurate-incommensurate transition in frustrated (flux) lattices). 3. Investigations of phenomena associated with non-equilibrium superconductivity in and around Josephson junctions (with high current density). (orig./BUD)

  2. Phased-array radars

    Science.gov (United States)

    Brookner, E.

    1985-02-01

    The operating principles, technology, and applications of phased-array radars are reviewed and illustrated with diagrams and photographs. Consideration is given to the antenna elements, circuitry for time delays, phase shifters, pulse coding and compression, and hybrid radars combining phased arrays with lenses to alter the beam characteristics. The capabilities and typical hardware of phased arrays are shown using the US military systems COBRA DANE and PAVE PAWS as examples.

  3. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water reflected (i.e., surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established. When evaluating arrays, it has become more common for analysts to use calculations to demonstrate the safety of the array configuration. In performing these calculations, the analyst has considerable freedom concerning the assumptions made for modeling the reflection of the array. Considerations are given for the physical layout of the array with little or no discussion (or demonstration) of what conditions are bounded by the assumed reflection conditions. For example, an array may be generically evaluated by placing it in a corner of a room in which the opposing walls are far away. Typically, it is believed that complete flooding of the room is incredible, so the array is evaluated for various levels of water mist interspersed among array containers. This paper discusses some assumptions that are made regarding storage array reflection

  4. The EUROBALL array

    International Nuclear Information System (INIS)

    Rossi Alvarez, C.

    1998-01-01

    The quality of the multidetector array EUROBALL is described, with emphasis on the history and formal organization of the related European collaboration. The detector layout is presented together with the electronics and Data Acquisition capabilities. The status of the instrument, its performances and the main features of some recently developed ancillary detectors will also be described. The EUROBALL array is operational in Legnaro National Laboratory (Italy) since April 1997 and is expected to run up to November 1998. The array represents a significant improvement in detector efficiency and sensitivity with respect to the previous generation of multidetector arrays

  5. Rectenna array measurement results

    Science.gov (United States)

    Dickinson, R. M.

    1980-01-01

    The measured performance characteristics of a rectenna array are reviewed and compared to the performance of a single element. It is shown that the performance may be extrapolated from the individual element to that of the collection of elements. Techniques for current and voltage combining were demonstrated. The array performance as a function of various operating parameters is characterized and techniques for overvoltage protection and automatic fault clearing in the array demonstrated. A method for detecting failed elements also exists. Instrumentation for deriving performance effectiveness is described. Measured harmonic radiation patterns and fundamental frequency scattered patterns for a low level illumination rectenna array are presented.

  6. Arrayed waveguide Sagnac interferometer.

    Science.gov (United States)

    Capmany, José; Muñoz, Pascual; Sales, Salvador; Pastor, Daniel; Ortega, Beatriz; Martinez, Alfonso

    2003-02-01

    We present a novel device, an arrayed waveguide Sagnac interferometer, that combines the flexibility of arrayed waveguides and the wide application range of fiber or integrated optics Sagnac loops. We form the device by closing an array of wavelength-selective light paths provided by two arrayed waveguides with a single 2 x 2 coupler in a Sagnac configuration. The equations that describe the device's operation in general conditions are derived. A preliminary experimental demonstration is provided of a fiber prototype in passive operation that shows good agreement with the expected theoretical performance. Potential applications of the device in nonlinear operation are outlined and discussed.

  7. Excitation of high density surface plasmon polariton vortex array

    Science.gov (United States)

    Kuo, Chun-Fu; Chu, Shu-Chun

    2018-06-01

    This study proposes a method to excite surface plasmon polariton (SPP) vortex array of high spatial density on metal/air interface. A doughnut vector beam was incident at four rectangularly arranged slits to excite SPP vortex array. The doughnut vector beam used in this study has the same field intensity distribution as the regular doughnut laser mode, TEM01* mode, but a different polarization distribution. The SPP vortex array is achieved through the matching of both polarization state and phase state of the incident doughnut vector beam with the four slits. The SPP field distribution excited in this study contains stable array-distributed time-varying optical vortices. Theoretical derivation, analytical calculation and numerical simulation were used to discuss the characteristics of the induced SPP vortex array. The period of the SPP vortex array induced by the proposed method had only half SPPs wavelength. In addition, the vortex number in an excited SPP vortex array can be increased by enlarging the structure.

  8. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  9. Instrumentation with polarized neutrons

    International Nuclear Information System (INIS)

    Boeni, P.; Muenzer, W.; Ostermann, A.

    2009-01-01

    Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

  10. Organic Poultry Feeding

    Directory of Open Access Journals (Sweden)

    Arda Yıldırım

    2014-02-01

    Full Text Available Many people have led to the consumption of organic animal products in the event that the increase in sensitivity to a healthy diet in developed countries, and maintaining the safety of food of animal origin. Feeding and breeding in conventional production are emerged some of the negative effects and also it is more in organic production with new restrictions. Organic production is based on animal welfare. On the basis of behaviors such as feather-pecking and cannibalism known to be low in protein level of rations and unbalanced in terms of amino acids or minerals. As of 2015, organic poultry feed provided the appropriate conditions that will be 95% organic certified in Turkey and therefore, to create a balanced ration and feed hygiene in protecting brings serious challenges. Fodder supply of organic poultry feed raw materials that make up the quality, quantity and issue forms a significant effect on the health of the poultry additives permitted. The quality of the feed raw materials that constituent diets, quantity, feed supplying form and permitted feed additives significantly affects the health of poultry. Different physiological stages of the animal's nutritional requirements in order to ensure production of quality poultry products must be met from organically produced and very well-known with the contents of feedstuff digestibility. In this study, the problems encountered in feeding can be eliminated while performing economic production with considering animal welfare, following that balanced and adequate organic ration formulations and issues such as improving the production of feed raw materials are discussed.

  11. Focal plane array with modular pixel array components for scalability

    Science.gov (United States)

    Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

    2014-12-09

    A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

  12. Monolithic microwave integrated circuit with integral array antenna

    International Nuclear Information System (INIS)

    Stockton, R.J.; Munson, R.E.

    1984-01-01

    A monolithic microwave integrated circuit including an integral array antenna. The system includes radiating elements, feed network, phasing network, active and/or passive semiconductor devices, digital logic interface circuits and a microcomputer controller simultaneously incorporated on a single substrate by means of a controlled fabrication process sequence

  13. Development of a superconducting elliptically polarized undulator

    International Nuclear Information System (INIS)

    Chen, S D; Liang, K S; Jan, J C; Hwang, C S

    2010-01-01

    A superconducting, elliptically polarized undulator (SEPU24) with a period of length 24 mm was developed to provide first-harmonic photons from a 0.8 GeV storage ring for extreme-ultraviolet (EUV) lithography experiment. In SEPU24, two layers of a magnet array structure - with and without rotated magnet arrays - are combined to generate a helical field that provides radiation with wavelength 13.5 nm in the in-band energy. The arrays of iron and aluminium poles were wound with a racetrack coil vertically as for the magnet pole array. The elliptical field is created when the up and down magnet-pole arrays pass excitation currents in alternate directions. SEPU24 is designed with a magnet of gap 6.8 mm, yielding magnetic flux density B x =B z =0.61 T of the helical field. A prototype magnet was fabricated with a diode for quench protection, and assembled in a test dewar to test the magnet performance. A cryogenic Hall-probe system with a precise linear stage was used to measure the distribution of the magnetic field. We describe the design concept and algorithm, the engineering design, the calculation of the magnetic field, the construction and testing of the 10-pole prototype magnet and related issues.

  14. Advanced ACTPol Cryogenic Detector Arrays and Readout

    Science.gov (United States)

    Henderson, S. W.; Allison, R.; Austermann, J.; Baildon, T.; Battaglia, N.; Beall, J. A.; Becker, D.; De Bernardis, F.; Bond, J. R.; Calabrese, E.; Choi, S. K.; Coughlin, K. P.; Crowley, K. T.; Datta, R.; Devlin, M. J.; Duff, S. M.; Dunkley, J.; Dünner, R.; van Engelen, A.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Hills, F.; Hilton, G. C.; Hincks, A. D.; Hloẑek, R.; Ho, S. P.; Hubmayr, J.; Huffenberger, K.; Hughes, J. P.; Irwin, K. D.; Koopman, B. J.; Kosowsky, A. B.; Li, D.; McMahon, J.; Munson, C.; Nati, F.; Newburgh, L.; Niemack, M. D.; Niraula, P.; Page, L. A.; Pappas, C. G.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sherwin, B. D.; Sievers, J. L.; Simon, S. M.; Spergel, D. N.; Staggs, S. T.; Stevens, J. R.; Thornton, R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope, adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background anisotropies—imaged in intensity and polarization at few arcminute-scale resolution—will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the Advanced ACTPol cryogenic detector arrays.

  15. Multiband Circular Polarizer Based on Fission Transmission of Linearly Polarized Wave for X-Band Applications

    Directory of Open Access Journals (Sweden)

    Farman Ali Mangi

    2016-01-01

    Full Text Available A multiband circular polarizer based on fission transmission of linearly polarized wave for x-band application is proposed, which is constructed of 2 × 2 metallic strips array. The linear-to-circular polarization conversion is obtained by decomposing the linearly incident x-polarized wave into two orthogonal vector components of equal amplitude and 90° phase difference between them. The innovative approach of “fission transmission of linear-to-circular polarized wave” is firstly introduced to obtain giant circular dichroism based on decomposition of orthogonal vector components through the structure. It means that the incident linearly polarized wave is converted into two orthogonal components through lower printed metallic strips layer and two transmitted waves impinge on the upper printed strips layer to convert into four orthogonal vector components at the end of structure. This projection and transmission sequence of orthogonal components sustain the chain transmission of electromagnetic wave and can achieve giant circular dichroism. Theoretical analysis and microwave experiments are presented to validate the performance of the structure. The measured results are in good agreement with simulation results. In addition, the proposed circular polarizer exhibits the optimal performance with respect to the normal incidence. The right handed circularly polarized wave is emitted ranging from 10.08 GHz to 10.53 GHz and 10.78 GHz to 11.12 GHz, while the left handed circular polarized wave is excited at 10.54 GHz–10.70 GHz and 11.13 GHz–11.14 GHz, respectively.

  16. A polarization-insensitive plasmonic photoconductive terahertz emitter

    KAUST Repository

    Li, Xurong

    2017-11-16

    We present a polarization-insensitive plasmonic photoconductive terahertz emitter that uses a two-dimensional array of nanoscale cross-shaped apertures as the plasmonic contact electrodes. The geometry of the cross-shaped apertures is set to maximize optical pump absorption in close proximity to the contact electrodes. The two-dimensional symmetry of the cross-shaped apertures offers a polarization-insensitive interaction between the plasmonic contact electrodes and optical pump beam. We experimentally demonstrate a polarization-insensitive terahertz radiation from the presented emitter in response to a femtosecond optical pump beam and similar terahertz radiation powers compared to previously demonstrated polarization-sensitive photoconductive emitters with plasmonic contact electrode gratings at the optimum optical pump polarization.

  17. Linear Polarization Properties of Parsec-Scale AGN Jets

    Directory of Open Access Journals (Sweden)

    Alexander B. Pushkarev

    2017-12-01

    Full Text Available We used 15 GHz multi-epoch Very Long Baseline Array (VLBA polarization sensitive observations of 484 sources within a time interval 1996–2016 from the MOJAVE program, and also from the NRAO data archive. We have analyzed the linear polarization characteristics of the compact core features and regions downstream, and their changes along and across the parsec-scale active galactic nuclei (AGN jets. We detected a significant increase of fractional polarization with distance from the radio core along the jet as well as towards the jet edges. Compared to quasars, BL Lacs have a higher degree of polarization and exhibit more stable electric vector position angles (EVPAs in their core features and a better alignment of the EVPAs with the local jet direction. The latter is accompanied by a higher degree of linear polarization, suggesting that compact bright jet features might be strong transverse shocks, which enhance magnetic field regularity by compression.

  18. Triggering the GRANDE array

    International Nuclear Information System (INIS)

    Wilson, C.L.; Bratton, C.B.; Gurr, J.; Kropp, W.; Nelson, M.; Sobel, H.; Svoboda, R.; Yodh, G.; Burnett, T.; Chaloupka, V.; Wilkes, R.J.; Cherry, M.; Ellison, S.B.; Guzik, T.G.; Wefel, J.; Gaidos, J.; Loeffler, F.; Sembroski, G.; Goodman, J.; Haines, T.J.; Kielczewska, D.; Lane, C.; Steinberg, R.; Lieber, M.; Nagle, D.; Potter, M.; Tripp, R.

    1990-01-01

    A brief description of the Gamma Ray And Neutrino Detector Experiment (GRANDE) is presented. The detector elements and electronics are described. The trigger logic for the array is then examined. The triggers for the Gamma Ray and the Neutrino portions of the array are treated separately. (orig.)

  19. ISS Solar Array Management

    Science.gov (United States)

    Williams, James P.; Martin, Keith D.; Thomas, Justin R.; Caro, Samuel

    2010-01-01

    The International Space Station (ISS) Solar Array Management (SAM) software toolset provides the capabilities necessary to operate a spacecraft with complex solar array constraints. It monitors spacecraft telemetry and provides interpretations of solar array constraint data in an intuitive manner. The toolset provides extensive situational awareness to ensure mission success by analyzing power generation needs, array motion constraints, and structural loading situations. The software suite consists of several components including samCS (constraint set selector), samShadyTimers (array shadowing timers), samWin (visualization GUI), samLock (array motion constraint computation), and samJet (attitude control system configuration selector). It provides high availability and uptime for extended and continuous mission support. It is able to support two-degrees-of-freedom (DOF) array positioning and supports up to ten simultaneous constraints with intuitive 1D and 2D decision support visualizations of constraint data. Display synchronization is enabled across a networked control center and multiple methods for constraint data interpolation are supported. Use of this software toolset increases flight safety, reduces mission support effort, optimizes solar array operation for achieving mission goals, and has run for weeks at a time without issues. The SAM toolset is currently used in ISS real-time mission operations.

  20. Multiphoton polarization Bremsstrahlung effect

    International Nuclear Information System (INIS)

    Golovinskij, P.A.

    2001-01-01

    A general approach to induced polarization effects was formulated on the basis of theory of many particles in a strong periodic field. Correlation with the perturbation theory is shown and the types of effective polarization potentials both for isolated atoms and ions, and for ions in plasma, are provided. State of art in the theory of forced polarization Bremsstrahlung effect is analyzed and some outlooks for further experimental and theoretical studies are outlined [ru

  1. Gastrostomy feeding tube - pump

    Science.gov (United States)

    ... button, close the clamp on the feeding set, disconnect the extension set from the button, and close ... Copyright Privacy Accessibility Quality Guidelines Viewers & Players MedlinePlus Connect for EHRs For Developers U.S. National Library of ...

  2. Feeding Your Baby

    Medline Plus

    Full Text Available ... Our work Community impact Global programs Research Need help? Frequently asked questions Contact us Tools & Resources Born ... your dashboard . Time to eat! Feeding your baby helps her grow healthy and strong. It’s also a ...

  3. Feeding Your Baby

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    Full Text Available ... baby Formula feeding How to breastfeed Keeping breast milk safe and healthy Problems and discomforts when breastfeeding ... health & safety ') document.write('') } Ask our experts! Have a ...

  4. Feeding Your Baby

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    Full Text Available ... baby Feeding your baby E-mail to a friend Please fill in all fields. Please enter a ... for your baby during the first year of life. Learn how to breastfeed and why breast milk ...

  5. Feeding Your Baby

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    Full Text Available ... Baby Caring for your baby Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & ... health research Prematurity research centers For providers NICU Family Support® Prematurity Campaign Collaborative Info for your patients ...

  6. Feeding Your Baby

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    Full Text Available ... Global Map Premature Birth Report Cards Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & ... Caring for your baby Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature ...

  7. Feeding Your Baby

    Medline Plus

    Full Text Available ... discomforts . If you’re feeding your baby formula , find out how to choose the best one for ... care they receive. We're pioneering research to find solutions. We're empowering families with the knowledge ...

  8. Feeding Your Baby

    Medline Plus

    Full Text Available ... this page It's been added to your dashboard . Time to eat! Feeding your baby helps her grow healthy and strong. It’s also a great time for you and your partner to bond with ...

  9. Feeding Your Baby

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    Full Text Available ... for your baby Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature birth The newborn intensive care unit (NICU) Birth defects & other health conditions Loss & grief Tools & Resources Frequently asked health questions ...

  10. Feeding Your Baby

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    Full Text Available ... bond with her. Breast milk is the best food for your baby during the first year of ... feeding safe. And then get ready for solid foods ! In This Topic Breastfeeding help Breastfeeding is best ...

  11. Feeding Your Baby

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    Full Text Available ... then get ready for solid foods ! In This Topic Breastfeeding help Breastfeeding is best Food allergies and ... breast pump Baby Feeding your baby Other Baby topics ') document.write(' Caring for your baby ') document.write('') } ') ...

  12. Teleost polarization vision: how it might work and what it might be good for.

    Science.gov (United States)

    Kamermans, Maarten; Hawryshyn, Craig

    2011-03-12

    In this review, we will discuss the recent literature on fish polarization vision and we will present a model on how the retina processes polarization signals. The model is based on a general retinal-processing scheme and will be compared with the available electrophysiological data on polarization processing in the retina. The results of this model will help illustrate the functional significance of polarization vision for both feeding behaviour and navigation. First, we examine the linkage between structure and function in polarization vision in general.

  13. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  14. Polarization of Be stars

    International Nuclear Information System (INIS)

    Johns, M.W.

    1975-01-01

    Linear polarization of starlight may be produced by electron scattering in the extended atmospheres of early type stars. Techniques are investigated for the measurement and interpretation of this polarization. Polarimetric observations were made of twelve visual double star systems in which at least one member was a B type star as a means of separating the intrinsic stellar polarization from the polarization produced in the interstellar medium. Four of the double stars contained a Be star. Evidence for intrinsic polarization was found in five systems including two of the Be systems, one double star with a short period eclipsing binary, and two systems containing only normal early type stars for which emission lines have not been previously reported. The interpretation of these observations in terms of individual stellar polarizations and their wavelength dependence is discussed. The theoretical basis for the intrinsic polarization of early type stars is explored with a model for the disk-like extended atmospheres of Be stars. Details of a polarimeter for the measurement of the linear polarization of astronomical point sources are also presented with narrow band (Δ lambda = 100A) measurements of the polarization of γ Cas from lambda 4000 to lambda 5800

  15. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

  16. Polarization-dependent diffraction in all-dielectric, twisted-band structures

    Energy Technology Data Exchange (ETDEWEB)

    Kardaś, Tomasz M.; Jagodnicka, Anna; Wasylczyk, Piotr, E-mail: pwasylcz@fuw.edu.pl [Photonic Nanostructure Facility, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warszawa (Poland)

    2015-11-23

    We propose a concept for light polarization management: polarization-dependent diffraction in all-dielectric microstructures. Numerical simulations of light propagation show that with an appropriately configured array of twisted bands, such structures may exhibit zero birefringence and at the same time diffract two circular polarizations with different efficiencies. Non-birefringent structures as thin as 3 μm have a significant difference in diffraction efficiency for left- and right-hand circular polarizations. We identify the structural parameters of such twisted-band matrices for optimum performance as circular polarizers.

  17. Concept of an interlaced phased array for beam switching

    Science.gov (United States)

    Reddy, C. A.; Janardhanan, K. V.; Mukundan, K. K.; Shenoy, K. S. V.

    1990-04-01

    A novel concept is described for feeding and phasing a large linear array of N antenna elements using only three or five feed points and phase shifters and still achieving beam switching. The idea consists of drastically reducing the number of input points by interlacing a small number of serially fed subarrays which are suitably phased. This so-called interlaced phased array (IPA) concept was tested using an array of 15 four-element Yagi antennas with a spacing equal to 0.8 wavelengths and found feasible. Some of the distinct advantages of the IPA in comparison with a conventional system of beam switching are reduced power loss, reduced phasing errors, reduced cost, increased reliability resulting from greatly reduced number of phase shifters, and better symmetry of off-zenith beams.

  18. Recent progress on HYSPEC, and its polarization analysis capabilities

    Directory of Open Access Journals (Sweden)

    Winn Barry

    2015-01-01

    Full Text Available HYSPEC is a high-intensity, direct-geometry time-of-flight spectrometer at the Spallation Neutron Source, optimized for measurement of excitations in small single-crystal specimens with optional polarization analysis capabilities. The incident neutron beam is monochromated using a Fermi chopper with short, straight blades, and is then vertically focused by Bragg scattering onto the sample position by either a highly oriented pyrolitic graphite (unpolarized or a Heusler (polarized crystal array. Neutrons are detected by a bank of 3He tubes that can be positioned over a wide range of scattering angles about the sample axis. HYSPEC entered the user program in February 2013 for unpolarized experiments, and is already experiencing a vibrant research program. Polarization analysis will be accomplished by using the Heusler crystal array to polarize the incident beam, and either a 3He spin filter or a supermirror wide-angle polarization analyser to analyse the scattered beam. The 3He spin filter employs the spin-exchange optical pumping technique. A 60∘ wide angle 3He cell that matches the detector coverage will be used for polarization analysis. The polarized gas in the post-sample wide angle cell is designed to be periodically and automatically refreshed with an adjustable pressure of polarized gas, optically pumped in a separate cell and then transferred to the wide angle cell. The supermirror analyser has 960 supermirror polarizers distributed over 60∘, and has been characterized at the Swiss Spallation Neutron Source. The current status of the instrument and the development of its polarization analysis capabilities are presented.

  19. Reconfigurable micromachined antenna with polarization diversity for mm-wave applications

    KAUST Repository

    Sallam, Mai O.

    2012-03-01

    In this paper a novel MEMS antenna with reconfigurable polarization operating at 60 GHz is presented. This antenna can provide vertical linear polarization, horizontal linear polarization, left hand circular polarization (LHCP), or right hand circular polarization (RHCP) based on the states of the switches present in the feeding network. The proposed antenna is characterized by having its radiating elements isolated from the feeding circuitry via a ground plane without the need for wafer bonding or hybrid integration. Such advantage results in good electric performance while maintains low fabrication cost. The antenna parameters are optimized using HFSS and the results are cross-validated using CST. The good agreement between the two simulators, confirms that the proposed antenna enjoys attractive radiation characteristics for all polarization senses. © 2012 IEEE.

  20. Reconfigurable micromachined antenna with polarization diversity for mm-wave applications

    KAUST Repository

    Sallam, Mai O.; Soliman, Ezzeldin A.; Sedky, Sherif

    2012-01-01

    In this paper a novel MEMS antenna with reconfigurable polarization operating at 60 GHz is presented. This antenna can provide vertical linear polarization, horizontal linear polarization, left hand circular polarization (LHCP), or right hand circular polarization (RHCP) based on the states of the switches present in the feeding network. The proposed antenna is characterized by having its radiating elements isolated from the feeding circuitry via a ground plane without the need for wafer bonding or hybrid integration. Such advantage results in good electric performance while maintains low fabrication cost. The antenna parameters are optimized using HFSS and the results are cross-validated using CST. The good agreement between the two simulators, confirms that the proposed antenna enjoys attractive radiation characteristics for all polarization senses. © 2012 IEEE.

  1. Antenna-coupled bolometer arrays using transition-edge sensors

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Michael J. [Department of Physics, University of California, Berkeley, California 94720 (United States)]. E-mail: mmyers@cosmology.berkeley.edu; Ade, Peter [School of Physics and Astronomy, Cardiff University, Cardiff, Wales (United Kingdom); Arnold, Kam [Department of Physics, University of California, Berkeley, California 94720 (United States); Engargiola, Greg [Department of Astronomy, University of California, Berkeley, California 94720 (United States); Holzapfel, Bill [Department of Physics, University of California, Berkeley, California 94720 (United States); Lee, Adrian T. [Department of Physics, University of California, Berkeley, California 94720 (United States); O' Brient, Roger [Department of Physics, University of California, Berkeley, California 94720 (United States); Richards, Paul L. [Department of Physics, University of California, Berkeley, California 94720 (United States); Smith, Andy [Northrop Grumman, Redondo Beach, California 90278 (United States); Spieler, Helmuth [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Tran, Huan T. [Department of Physics, University of California, Berkeley, California 94720 (United States)

    2006-04-15

    We are developing antenna-coupled Transition-Edge Sensor (TES) bolometer arrays for use in measurements of the CMB polarization. TES bolometers have many well-known advantages over conventional bolometers, such as increased speed, linearity, and the existence of readout multiplexers. Antenna-coupled bolometers use an on-chip planar antenna to couple light into the bolometer. The antenna directivity and polarization sensitivity, along with the potential for on-chip band defining filters and channelizing circuits, allow a significant increase in focal plane integration. This eliminates the bulky horns, quasioptical filters, dichroics, and polarizers which might otherwise be needed in a conventional bolometric system. This simplification will ease the construction of receivers with larger numbers of pixels. We report on the fabrication and optical testing of single antenna-coupled bolometer pixels with integrated band defining filters. We will also discuss current progress on fabrication of a bolometer array based on this design.

  2. Alternating gradient focusing and deceleration of polar molecules

    NARCIS (Netherlands)

    Bethlem, H.L.; Tarbutt, M.R.; Kupper, J.; Carty, D.; Wohlfart, K.; Hinds, E.A.; Meijer, G.

    2006-01-01

    Beams of polar molecules can be focused using an array of electrostatic lenses in alternating gradient (AG) configuration. They can also be accelerated or decelerated by applying an appropriate high-voltage switching sequence to the lenses. AG focusing is applicable to molecules in both low-field-

  3. Generation and propagation of radially polarized beams in optical fibers

    DEFF Research Database (Denmark)

    Ramachandran, Siddharth; Kristensen, P; Yan, M F

    2009-01-01

    Beams with polarization singularities have attracted immense recent attention in a wide array of scientific and technological disciplines. We demonstrate a class of optical fibers in which these beams can be generated and propagated over long lengths with unprecedented stability, even...

  4. Next Generation Polar Seismic Instrumentation Challenges

    Science.gov (United States)

    Parker, T.; Beaudoin, B. C.; Gridley, J.; Anderson, K. R.

    2011-12-01

    Polar region logistics are the limiting factor for deploying deep field seismic arrays. The IRIS PASSCAL Instrument Center, in collaboration with UNAVCO, designed and deployed several systems that address some of the logistical constraints of polar deployments. However, continued logistics' pressures coupled with increasingly ambitious science projects require further reducing the logistics required for deploying both summer and over winter stations. Our focus is to reduce station power requirements and bulk, thereby minimizing the time and effort required to deploy these arrays. We will reduce the weight of the battery bank by incorporating the most applicable new high energy-density battery technology. Using these batteries will require a completely new power management system along with an appropriate smart enclosure. The other aspect will be to integrate the digitizing system with the sensor. Both of these technologies should reduce the install time and shipping volume plus weight while reducing some instrument costs. We will also continue work on an effective Iridium telemetry solution for automated data return. The costs and limitations of polar deep-field science easily justifies a specialized development effort but pays off doubly in that we will continue to leverage the advancements in reduced logistics and increased performance for the benefit of low-latitude seismic research.

  5. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed. The...

  6. Sensor array signal processing

    CERN Document Server

    Naidu, Prabhakar S

    2009-01-01

    Chapter One: An Overview of Wavefields 1.1 Types of Wavefields and the Governing Equations 1.2 Wavefield in open space 1.3 Wavefield in bounded space 1.4 Stochastic wavefield 1.5 Multipath propagation 1.6 Propagation through random medium 1.7 ExercisesChapter Two: Sensor Array Systems 2.1 Uniform linear array (ULA) 2.2 Planar array 2.3 Distributed sensor array 2.4 Broadband sensor array 2.5 Source and sensor arrays 2.6 Multi-component sensor array2.7 ExercisesChapter Three: Frequency Wavenumber Processing 3.1 Digital filters in the w-k domain 3.2 Mapping of 1D into 2D filters 3.3 Multichannel Wiener filters 3.4 Wiener filters for ULA and UCA 3.5 Predictive noise cancellation 3.6 Exercises Chapter Four: Source Localization: Frequency Wavenumber Spectrum4.1 Frequency wavenumber spectrum 4.2 Beamformation 4.3 Capon's w-k spectrum 4.4 Maximum entropy w-k spectrum 4.5 Doppler-Azimuth Processing4.6 ExercisesChapter Five: Source Localization: Subspace Methods 5.1 Subspace methods (Narrowband) 5.2 Subspace methods (B...

  7. Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

    Science.gov (United States)

    Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

    2016-03-01

    Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

  8. Design and control of phased ICRF antenna arrays

    International Nuclear Information System (INIS)

    Goulding, R.H.; Baity, F.W.; Hoffman, D.J.

    1993-01-01

    Phased antenna arrays operating in the ion cyclotron range of frequencies (ICRF) are used to produce highly directional wave spectra, primarily for use in current drive experiments. RF current drive using phased antennas has been demonstrated in both the JET and DIII-D tokamaks, and both devices are planning to operate new four-element arrays beginning early next year. Features of antenna design that are relevant to phased operation and production of directional spectra are reviewed. Recent advances in the design of the feed circuits and the related control systems for these arrays should substantially improve their performance, by reducing the coupling seen by the matching networks and rf power supplies caused by the mutual impedance of the array elements. The feed circuit designs for the DIII-D and JET phased antenna arrays are compared. The two configurations differ significantly due to the fact that one power amplifier is used for the entire array in the former case, and one per element in the latter. The JET system uses automatic feedback control of matching, phase and amplitude of antenna currents, and the transmitter power balance. The design of this system is discussed, and a time dependent model used to predict its behavior is described

  9. TRANSVERSELY POLARIZED Λ PRODUCTION

    International Nuclear Information System (INIS)

    BORER, D.

    2000-01-01

    Transversely polarized Λ production in hard scattering processes is discussed in terms of a leading twist T-odd fragmentation function which describes the fragmentation of an unpolarized quark into a transversely polarized Λ. We focus on the properties of this function and its relevance for the RHIC and HERMES experiments

  10. Our Polar Past

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  11. Marine polar steroids

    International Nuclear Information System (INIS)

    Stonik, Valentin A

    2001-01-01

    Structures, taxonomic distribution and biological activities of polar steroids isolated from various marine organisms over the last 8-10 years are considered. The peculiarities of steroid biogenesis in the marine biota and their possible biological functions are discussed. Syntheses of some highly active marine polar steroids are described. The bibliography includes 254 references.

  12. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  13. Localized surface phonon polariton resonances in polar gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Kaijun, E-mail: kfeng@nd.edu; Islam, S. M.; Verma, Jai; Hoffman, Anthony J. [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Streyer, William; Wasserman, Daniel [Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801 (United States); Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14850 (United States)

    2015-08-24

    We demonstrate the excitation of localized surface phonon polaritons in an array of sub-diffraction pucks fabricated in an epitaxial layer of gallium nitride (GaN) on a silicon carbide (SiC) substrate. The array is characterized via polarization- and angle-dependent reflection spectroscopy in the mid-infrared, and coupling to several localized modes is observed in the GaN Reststrahlen band (13.4–18.0 μm). The same structure is simulated using finite element methods and the charge density of the modes are studied; transverse dipole modes are identified for the transverse electric and magnetic polarizations and a quadrupole mode is identified for the transverse magnetic polarization. The measured mid-infrared spectrum agrees well with numerically simulated spectra. This work could enable optoelectronic structures and devices that support surface modes at mid- and far-infrared wavelengths.

  14. Centrosome polarization in T cells: a task for formins

    Directory of Open Access Journals (Sweden)

    Laura eAndrés-Delgado

    2013-07-01

    Full Text Available T-cell antigen receptor (TCR engagement triggers the rapid reorientation of the centrosome, which is associated with the secretory machinery, towards the immunological synapse (IS for polarized protein trafficking. Recent evidence indicates that upon TCR triggering the INF2 formin, together with the formins DIA1 and FMNL1, promotes the formation of a specialized array of stable detyrosinated MTs that breaks the symmetrical organization of the T-cell microtubule (MT cytoskeleton. The detyrosinated MT array and TCR-induced tyrosine phosphorylation should coincide for centrosome polarization. We propose that the pushing forces produced by the detyrosinated MT array, which modify the position of the centrosome, in concert with Src kinase dependent TCR signaling, which provide the reference frame with respect to which the centrosome reorients, result in the repositioning of the centrosome to the IS.

  15. Introduction to adaptive arrays

    CERN Document Server

    Monzingo, Bob; Haupt, Randy

    2011-01-01

    This second edition is an extensive modernization of the bestselling introduction to the subject of adaptive array sensor systems. With the number of applications of adaptive array sensor systems growing each year, this look at the principles and fundamental techniques that are critical to these systems is more important than ever before. Introduction to Adaptive Arrays, 2nd Edition is organized as a tutorial, taking the reader by the hand and leading them through the maze of jargon that often surrounds this highly technical subject. It is easy to read and easy to follow as fundamental concept

  16. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

  17. An Antenna Measurement System Based on Optical Feeding

    Directory of Open Access Journals (Sweden)

    Ryohei Hosono

    2013-01-01

    the advantage of the system is demonstrated by measuring an ultra-wideband (UWB antenna both by the optical and electrical feeding systems and comparing with a calculated result. Ripples in radiation pattern due to the electrical feeding are successfully suppressed by the optical feeding. For example, in a radiation measurement on the azimuth plane at 3 GHz, ripple amplitude of 1.0 dB that appeared in the electrical feeding is reduced to 0.3 dB. In addition, a circularly polarized (CP antenna is successfully measured by the proposed system to show that the system is available not only for amplitude but also phase measurements.

  18. Polarization Optics in Telecommunications

    CERN Document Server

    Damask, Jay N

    2005-01-01

    The strong investments into optical telecommunications in the late 1990s resulted in a wealth of new research, techniques, component designs, and understanding of polarization effects in fiber. Polarization Optics in Telecommunications brings together recent advances in the field to create a standard, practical reference for component designers and optical fiber communication engineers. Beginning with a sound foundation in electromagnetism, the author offers a dissertation of the spin-vector formalism of polarization and the interaction of light with media. Applications discussed include optical isolators, optical circulators, fiber collimators, and a variety of applied waveplate and prism combinations. Also included in an extended discussion of polarization-mode dispersion (PMD) and polarization-dependent loss (PDL), their representation, behavior, statistical properties, and measurement. This book draws extensively from the technical and patent literature and is an up-to-date reference for researchers and c...

  19. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  20. Status of the development of Brazilian Decimetric Array (BDA)

    Science.gov (United States)

    Sawant, Hanumant; Fernandes, Francisco; Chellasamy, Ebenezer; Cecatto, Jose R.; Costa, D. Joaquim; Sirothia, Sandeep Kumar; Subramanian, Koovapady

    BDA will consists of 38 antennas of 4 meters diameter, capable of operating at frequency range of (1.2-1.7, 2.8 and 5.6) GHz. The array will be spread over the distances 2 x 1 km in a T shape with longest base line in E-W direction, having spatial resolution of ~10 sec of arc at 5.6 GHz. The visibility data can be processed to provide two dimensional images at a time resolution of 100 ms (or higher). In the second phase of the BDA, almost all systems of the 26 antennas are installed. LO of 10 MHz is send from receiver room to each receiver located in the each antenna tower. This receiver operates in the frequency range of 1-6 GHz and converts received signal to 70 MHz. Fiber optical system is partially installed in tower converts 70 MHz signal to optical signal and send to receiver room with low loss and phase compensation of 100 ps, where it is converted back to 70 MHz and processed to give output of 0-5 MHz bandpass and further processed by the correlator. Tracking system, with Dual feed back facility has tracking accuracy of +/- 3 arc minutes. All safety features are installed, with on line offset adjustment. Data logging and event logging for future investigations are available. Tracking system was tested for one month with 8 hours tracking and results of these will also be presented. Field programmable Gate Array based complex correlator system capable of producing all four Stokes parameters was designed and developed for correlating base band outputs from 38 antennas. The correlator produces delay and fringe corrected, visibility correlations between any two signal channels of the same polarizations from any given pair of antennas, providing visibility data. Fringes using this system have been obtained for baseline combinations of 12 fully installed antennas. Simulations of the UV coverage and imaging were carried out for the full synthesis observations of sources at different configurations and various declinations in -70 to +23 degrees range. The current

  1. Mutual Coupling Effects for Radar Cross Section (RCS of a Series-Fed Dipole Antenna Array

    Directory of Open Access Journals (Sweden)

    H. L. Sneha

    2012-01-01

    Full Text Available The estimation of RCS of a phased array depends on various parameters, namely, array geometry, operational frequency, feed network, mutual coupling between the antenna elements and so fourth. This paper presents the estimation of RCS of linear dipole array with series-feed network by tracing the signal path from the antenna aperture into the feed network. The effect of mutual coupling exhibited by the dipole antenna is considered for three configurations namely, side by side, collinear, and parallel in echelon. It is shown that the mutual coupling affects the antenna pattern (and hence RCS significantly for larger scan angles. Further it is inferred that the RCS of phased array can be optimized by (i reducing the length of the dipole, (ii termination of the isolation port of the coupler with a suitable load, and (iii using suitable amplitude distribution.

  2. Design of a Compact Wideband Antenna Array for Microwave Imaging Applications

    Directory of Open Access Journals (Sweden)

    J. Puskely

    2013-12-01

    Full Text Available In the paper, wideband antenna arrays aimed at microwave imaging applications and SAR applications operating at Ka band were designed. The antenna array feeding network is realized by a low-loss SIW technology. Moreover, we have replaced the large feed network comprised of various T and Y junctions by a simple broadband network of compact size to more reduce losses in the substrate integrated waveguide and also save space on the PCB. The designed power 8-way divider is complemented by a wideband substrate integrated waveguide to a grounded coplanar waveguide transition and directly connected to the antenna elements. The measured results of antenna array are consistent with our simulation. Obtained results of the developed array demonstrated improvement compared to previously developed binary feed networks with microstrip or SIW splitters.

  3. Protein Functionalized Nanodiamond Arrays

    Directory of Open Access Journals (Sweden)

    Liu YL

    2010-01-01

    Full Text Available Abstract Various nanoscale elements are currently being explored for bio-applications, such as in bio-images, bio-detection, and bio-sensors. Among them, nanodiamonds possess remarkable features such as low bio-cytotoxicity, good optical property in fluorescent and Raman spectra, and good photostability for bio-applications. In this work, we devise techniques to position functionalized nanodiamonds on self-assembled monolayer (SAMs arrays adsorbed on silicon and ITO substrates surface using electron beam lithography techniques. The nanodiamond arrays were functionalized with lysozyme to target a certain biomolecule or protein specifically. The optical properties of the nanodiamond-protein complex arrays were characterized by a high throughput confocal microscope. The synthesized nanodiamond-lysozyme complex arrays were found to still retain their functionality in interacting with E. coli.

  4. Photonic Crystal Nanocavity Arrays

    National Research Council Canada - National Science Library

    Altug, Hatice; Vuckovic, Jelena

    2006-01-01

    We recently proposed two-dimensional coupled photonic crystal nanocavity arrays as a route to achieve a slow-group velocity of light in all crystal directions, thereby enabling numerous applications...

  5. Polar-interferometry: what can be learnt from the IOTA/IONIC experiment

    Science.gov (United States)

    Le Bouquin, Jean-Baptiste; Rousselet-Perraut, Karine; Berger, Jean-Philippe; Herwats, Emilie; Benisty, Myriam; Absil, Olivier; Defrere, Denis; Monnier, John; Traub, Wesley

    2008-07-01

    We report the first near-IR polar-interferometric observations, performed at the IOTA array using its integrated optics combiner IONIC. Fringes have been obtained on calibration stars and resolved late-type giants. Optical modeling of the array and dedicated laboratory measures allowed us to confirm the good accuracy obtained on the calibrated polarized visibilities and closure phases. However, no evidences for polarimetric features at high angular resolution have been detected. The simulations and the results presented here open several perspectives for polar-interferometry, especially in the context of fibered, single-mode combiners.

  6. Total elimination of sampling errors in polarization imagery obtained with integrated microgrid polarimeters.

    Science.gov (United States)

    Tyo, J Scott; LaCasse, Charles F; Ratliff, Bradley M

    2009-10-15

    Microgrid polarimeters operate by integrating a focal plane array with an array of micropolarizers. The Stokes parameters are estimated by comparing polarization measurements from pixels in a neighborhood around the point of interest. The main drawback is that the measurements used to estimate the Stokes vector are made at different locations, leading to a false polarization signature owing to instantaneous field-of-view (IFOV) errors. We demonstrate for the first time, to our knowledge, that spatially band limited polarization images can be ideally reconstructed with no IFOV error by using a linear system framework.

  7. Establishing breast feeding in hospital.

    OpenAIRE

    Levi, J

    1988-01-01

    The experience and practice of the author is described in her appointment as a breast feeding advisor to the paediatric and obstetric units at University College Hospital with special responsibility for supervising infant feeding, especially breast feeding in the maternity unit. During 1980-5 there were 13,185 mothers whose babies fed. The feeding method of 12,842 mothers was recorded on discharge from the postnatal wards and 77% were breast feeding; only 3% of these mothers gave complement f...

  8. Polarized triple-axis spectrometer TASP

    Energy Technology Data Exchange (ETDEWEB)

    Boeni, P; Keller, P [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    The polarized triple-axis spectrometer TASP at SINQ has been optimized for measuring magnetic cross sections in condensed matter. The neutrons are polarized or analyzed either by means of benders or Heusler monochromators. The beam divergence, i.e. the intensity, and the spectral range of the neutrons is rather large because of the supermirror coatings of the feeding neutron guide. The intensity can be further increased at the sample position by means of a focussing monochromator and a focussing anti-trumpet. The end position of TASP allows the tailoring of the neutron beam already before the monochromator and to scatter neutrons over very wide ranges of angles. (author) 6 figs., 1 tab., 8 refs.

  9. Cannabis and Breast feeding

    Energy Technology Data Exchange (ETDEWEB)

    Garry, A [Department dIngenierie Biologique, Ecole Polytechnique de Universite de Nice - Sophia Antipolis, 1645 Route des Lucioles, 06410 Biot (France); Virginie Rigourd, V; Aubry, S [Lactarium d' Ile de France, Institut de Puericulture et de Perinatalogie, 26 Boulevard Brune, 75014 Paris (France); Amirouche, A; Fauroux, V [Centre de Recherche Clinique Paris Centre, 89 rue d' Assas, 75006 Paris (France); Serreau, R [Centre de Recherche Clinique Paris Centre EA 3620, 89 rue d' Assas 75006 Paris (France)

    2009-07-01

    Cannabis is a drug derived from hemp plant, Cannabis sativa, used both as a recreational drug or as medicine. It is a widespread illegal substance, generally smoked for its hallucinogenic properties. Little is known about the adverse effects of postnatal cannabis exposure throw breast feeding because of a lack of studies in lactating women. The active substance of cannabis is the delta 9 Tetrahydrocannabinol (THC). Some studies conclude that it could decrease motor development of the child at one year of age. Therefore, cannabis use and abuse of other drugs like alcohol, tobacco, or cocaine must be contraindicated during breast feeding. Mothers who use cannabis must stop breast feeding, or ask for medical assistance to stop cannabis use in order to provide her baby with all the benefits of human milk.

  10. Cannabis and Breast feeding

    International Nuclear Information System (INIS)

    Garry, A.; Virginie Rigourd, V.; Aubry, S.; Amirouche, A.; Fauroux, V.; Serreau, R.

    2009-01-01

    Cannabis is a drug derived from hemp plant, Cannabis sativa, used both as a recreational drug or as medicine. It is a widespread illegal substance, generally smoked for its hallucinogenic properties. Little is known about the adverse effects of postnatal cannabis exposure throw breast feeding because of a lack of studies in lactating women. The active substance of cannabis is the delta 9 Tetrahydrocannabinol (THC). Some studies conclude that it could decrease motor development of the child at one year of age. Therefore, cannabis use and abuse of other drugs like alcohol, tobacco, or cocaine must be contraindicated during breast feeding. Mothers who use cannabis must stop breast feeding, or ask for medical assistance to stop cannabis use in order to provide her baby with all the benefits of human milk.

  11. Feed and organic matter

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang

    2011-01-01

    impact on the receiving water body by reducing dissolved oxygen concentrations and increasing sedimentation. Within aquaculture systems, a high organic load may affect fish health and performance directly (e.g., gill disease) as well as indirectly (proliferation of pathogenic bacteria and parasites......, reduction of dissolved oxygen concentrations, etc.). In recirculating aquaculture systems (RAS), a high organic load caused by limited water exchange may affect biofilter performance by favouring heterotrophic bacteria at the expense of autotrophic, nitrifying bacteria. Organic waste in RAS primarily...... originates from undigested feed, but also metabolic losses, mucus, dead tissue, feed waste and intake water may contribute. The nutrient composition of the feed affects the quantity and composition of the organic (undigested) waste, and including for example plant protein ingredients may affect...

  12. Cosmic microwave background polarization results from QUIET

    International Nuclear Information System (INIS)

    Buder, I.

    2014-01-01

    Despite the success of precision cosmology, cosmologists cannot fully explain the initial conditions of the Universe. Inflation, an exponential expansion in the first ∼ 10 -36 s, is a promising potential explanation. A generic prediction of inflation is odd-parity (B-mode) polarization in the cosmic microwave background (CMB). Q/U Imaging Experiment (QUIET) aimed at limiting or detecting this polarization. We built a pseudo-correlation microwave polarimeter as an array of mass-produced modules in the focal plane of a 1.4 m telescope. We used rotation around the absorbing ground screen, a new time-stream double-demodulation technique, and optimized optics in the design to reduce instrumental polarization. We observed with this instrument at the Atacama Plateau in Chile between October 2008 and December 2010. This paper describes the analysis and results of these observations from one of 2 parallel pipelines. We developed noise modeling, filtering and data selection following a blind-analysis strategy. Central to this strategy was a suite of null test, each motivated by a possible instrumental problem or systematic effect. We evaluated the systematic errors in the blind stage of the analysis before the result was known. We calculated the CMB power spectra using a pseudo-C l cross-correlation technique that suppressed contamination and made the result insensitive to noise bias. We measured the first 3 peaks of the E-mode spectrum at high significance and limited B-mode polarization. We measured the CMB polarization power at 25 ≤ l ≤ 975. We found no statistically significant deviation from ΛCDM model, and our results are consistent with zero BB and EB power. Systematic errors were well below our B-mode polarization limits. This systematic-error reduction was a strong demonstration of technology for application in more sensitive, next generation CMB experiments. (author)

  13. Carbon nanotube array actuators

    International Nuclear Information System (INIS)

    Geier, S; Mahrholz, T; Wierach, P; Sinapius, M

    2013-01-01

    Experimental investigations of highly vertically aligned carbon nanotubes (CNTs), also known as CNT-arrays, are the main focus of this paper. The free strain as result of an active material behavior is analyzed via a novel experimental setup. Previous test experiences of papers made of randomly oriented CNTs, also called Bucky-papers, reveal comparably low free strain. The anisotropy of aligned CNTs promises better performance. Via synthesis techniques like chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD), highly aligned arrays of multi-walled carbon nanotubes (MWCNTs) are synthesized. Two different types of CNT-arrays are analyzed, morphologically first, and optically tested for their active characteristics afterwards. One type of the analyzed arrays features tube lengths of 750–2000 μm with a large variety of diameters between 20 and 50 nm and a wave-like CNT-shape. The second type features a maximum, almost uniform, length of 12 μm and a constant diameter of 50 nm. Different CNT-lengths and array types are tested due to their active behavior. As result of the presented tests, it is reported that the quality of orientation is the most decisive property for excellent active behavior. Due to their alignment, CNT-arrays feature the opportunity to clarify the actuation mechanism of architectures made of CNTs. (paper)

  14. Design of broadband single polarized antenna

    Science.gov (United States)

    Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

    2015-05-01

    In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

  15. Xanthophylls in Poultry Feeding

    Science.gov (United States)

    Breithaupt, Diemar R.

    Since most consumers associate an intense colour of food with healthy animals and high food quality, xanthophylls are widely used as feed additives to generate products that meet consumers' demands. An important large-scale application is in poultry farming, where xanthophylls are added to feed to give the golden colour of egg yolk that is so much appreciated. Now, with numerous new applications in human food, in the pharmaceutical industry, and in cosmetic products, there is an increasing demand for xanthophylls on the international market (Volume 5, Chapter 4).

  16. Assessment of tissue viability by polarization spectroscopy

    Science.gov (United States)

    Nilsson, G.; Anderson, C.; Henricson, J.; Leahy, M.; O'Doherty, J.; Sjöberg, F.

    2008-09-01

    A new and versatile method for tissue viability imaging based on polarization spectroscopy of blood in superficial tissue structures such as the skin is presented in this paper. Linearly polarized light in the visible wavelength region is partly reflected directly by the skin surface and partly diffusely backscattered from the dermal tissue matrix. Most of the directly reflected light preserves its polarization state while the light returning from the deeper tissue layers is depolarized. By the use of a polarization filter positioned in front of a sensitive CCD-array, the light directly reflected from the tissue surface is blocked, while the depolarized light returning from the deeper tissue layers reaches the detector array. By separating the colour planes of the detected image, spectroscopic information about the amount of red blood cells (RBCs) in the microvascular network of the tissue under investigation can be derived. A theory that utilizes the differences in light absorption of RBCs and bloodless tissue in the red and green wavelength region forms the basis of an algorithm for displaying a colour coded map of the RBC distribution in a tissue. Using a fluid model, a linear relationship (cc. = 0.99) between RBC concentration and the output signal was demonstrated within the physiological range 0-4%. In-vivo evaluation using transepidermal application of acetylcholine by the way of iontophoresis displayed the heterogeneity pattern of the vasodilatation produced by the vasoactive agent. Applications of this novel technology are likely to be found in drug and skin care product development as well as in the assessment of skin irritation and tissue repair processes and even ultimately in a clinic case situation.

  17. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  18. Impact of Mutual Coupling and Polarization of Antennas on BER Performances of Spatial Multiplexing MIMO Systems

    Directory of Open Access Journals (Sweden)

    Jianfeng Zheng

    2012-01-01

    Full Text Available This paper is aimed at studying the impacts of mutual coupling, matching networks, and polarization of antennas on performances of Multiple-Input Multiple-Output (MIMO systems employing Spatial Multiplexing (SM. In particular, the uncoded average Bit Error Rate (BER of MIMO systems is investigated. An accurate signal analysis framework based on circuit network parameters is presented to describe the transmit/receive characteristics of the matched/unmatched antenna array. The studied arrays consist of matched/unmatched compact copolarization and polarization diversity antenna array. Monte-Carlo numerical simulations are used to study the BER performances of the SM MIMO systems using maximum-likelihood and/or zero-forcing detection schemes. The simulation results demonstrate that the use of matching networks can improve the BER performance of SM MIMO systems significantly, and the BER performance deterioration due to antenna orientation randomness can be compensated by use of polarization diversity antenna arrays.

  19. GUIDE FOR POLARIZED NEUTRONS

    Science.gov (United States)

    Sailor, V.L.; Aichroth, R.W.

    1962-12-01

    The plane of polarization of a beam of polarized neutrons is changed by this invention, and the plane can be flipped back and forth quicitly in two directions in a trouble-free manner. The invention comprises a guide having a plurality of oppositely directed magnets forming a gap for the neutron beam and the gaps are spaced longitudinally in a spiral along the beam at small stepped angles. When it is desired to flip the plane of polarization the magnets are suitably rotated to change the direction of the spiral of the gaps. (AEC)

  20. Heidelberg polarized alkali source

    International Nuclear Information System (INIS)

    Kraemer, D.; Steffens, E.; Jaensch, H.; Philipps Universitaet, Marburg, Germany)

    1984-01-01

    A new atomic beam type polarized alkali ion source has been installed at Heidelberg. In order to improve the beam polarization considerably optical pumping is applied in combination with an adiabatic medium field transition which results in beams in single hyperfine sublevels. The m state population is determined by laser-induced fluorescence spectroscopy. Highly polarized beams (P/sub s/ > 0.9, s = z, zz) with intensities of 30 to 130 μA can be extracted for Li + and Na + , respectively

  1. The representation of neutron polarization

    International Nuclear Information System (INIS)

    Byrne, J.

    1979-01-01

    Neutron beam polarization representation is discussed under the headings; transfer matrices, coherent parity violation for neutrons, neutron spin rotation in helical magnetic fields, polarization and interference. (UK)

  2. Creep feeding nursing beef calves.

    Science.gov (United States)

    Lardy, Gregory P; Maddock, Travis D

    2007-03-01

    Creep feeding can be used to increase calf weaning weights. However, the gain efficiency of free-choice, energy-based creep feeds is relatively poor. Generally, limit-feeding, high-protein creep feeds are more efficient, and gains may be similar to those produced by creep feeds offered free choice. Creep feeding can increase total organic matter intake and improve the overall energy status of the animal. Creep-fed calves tend to acclimate to the feedlot more smoothly than unsupplemented calves. Furthermore, provision of a high-starch creep feed may have a positive influence on subsequent carcass quality traits. Creep feeding can be applied to numerous environmental situations to maximize calf performance; however, beef cattle producers should consider their individual situations carefully before making the decision to creep feed.

  3. Source localization using a non-cocentered orthogonal loop and dipole (NCOLD) array

    Institute of Scientific and Technical Information of China (English)

    Liu Zhaoting; Xu Tongyang

    2013-01-01

    A uniform array of scalar-sensors with intersensor spacings over a large aperture size generally offers enhanced resolution and source localization accuracy, but it may also lead to cyclic ambiguity. By exploiting the polarization information of impinging waves, an electromagnetic vec-tor-sensor array outperforms the unpolarized scalar-sensor array in resolving this cyclic ambiguity. However, the electromagnetic vector-sensor array usually consists of cocentered orthogonal loops and dipoles (COLD), which is easily subjected to mutual coupling across these cocentered dipoles/loops. As a result, the source localization performance of the COLD array may substantially degrade rather than being improved. This paper proposes a new source localization method with a non-cocentered orthogonal loop and dipole (NCOLD) array. The NCOLD array contains only one dipole or loop on each array grid, and the intersensor spacings are larger than a half-wave-length. Therefore, unlike the COLD array, these well separated dipoles/loops minimize the mutual coupling effects and extend the spatial aperture as well. With the NCOLD array, the proposed method can efficiently exploit the polarization information to offer high localization precision.

  4. Feeding of Diarmis Proboscis

    Science.gov (United States)

    Young, Jocelyn

    2005-01-01

    The feeding of Diarmis proboscis is an exciting outdoor laboratory activity that demonstrates a single concept of adaptations--cryptic colorations. The students are "transformed" into D. proboscis (no Harry Potter magic needed) in order to learn how adaptations work in the natural world. Prior to beginning this activity, students should have a…

  5. Feeding Your Baby

    Medline Plus

    Full Text Available ... mail was sent. Save to my dashboard Sign in or Sign up to save this page. Saving Just a moment, please. You've saved this page It's been added to your dashboard . Time to eat! Feeding your baby helps her grow ...

  6. Interactive baby feeding bottle

    NARCIS (Netherlands)

    2013-01-01

    An interactive baby bottle with an electronic unit is disclosed. The electronic unit comprises a sensor unit configured to sense the heart beat of a person bottle feeding a baby and an actuator unit configured to transmit the sensed heart beat to the baby. The disclosed interactive baby bottle can

  7. Feed sources for livestock

    NARCIS (Netherlands)

    Zanten, van H.H.E.

    2016-01-01

    Production of food has re-emerged at the top of the global political agenda, driven by two contemporary challenges: the challenge to produce enough nutritious food to feed a growing and more prosperous human population, and the challenge to produce this food in an environmentally sustainable way.

  8. Feeding Your Baby

    Medline Plus

    Full Text Available ... Global Map Premature Birth Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? ... Feeding your baby Family health & safety Complications & Loss Pregnancy complications Preterm labor & premature birth The newborn intensive ...

  9. Low Emission Feed

    NARCIS (Netherlands)

    Klop, G.

    2016-01-01

    Research into manipulating methane (CH4) production as a result of enteric fermentation in ruminants currently receives global interest. Using feed additives may be a feasible strategy to mitigate CH4 as they are supplied in such amounts that the basal diet composition will not be largely

  10. New feed ingredients

    NARCIS (Netherlands)

    Raamsdonk, van L.W.D.; Fels-Klerx, van der H.J.; Jong, de J.

    2017-01-01

    In the framework of sustainability and a circular economy, new ingredients for feed are desired and, to this end, initiatives for implementing such novel ingredients have been started. The initiatives include a range of different sources, of which insects are of particular interest. Within the

  11. Effect of feed presentation on feeding patterns of dairy calves.

    Science.gov (United States)

    Miller-Cushon, E K; Bergeron, R; Leslie, K E; Mason, G J; DeVries, T J

    2013-01-01

    The objectives of this study were to determine the effect of feed presentation on meal frequency and duration, as well as diurnal feeding patterns of dairy calves, and to assess any longer-term differences in feeding patterns resulting from previous experience. Twenty Holstein bull calves were exposed from wk 1 to 8 of life to 1 of 2 feed presentation treatments: concentrate and chopped grass hay (Feed was provided ad libitum. Calves received 8L/d of milk replacer (1.2 kg of dry matter), with the amount progressively reduced after 5 wk to facilitate weaning by the end of wk 7. At the beginning of wk 9, all calves received the MIX diet and remained on trial for an additional 3 wk. Feeding behavior was recorded from video for 4d during wk 6, 8, 9, and 11. In wk 6, calves fed MIX spent more time feeding than calves fed COM (56.7 vs. 46.8 min/d). In wk 8, calves fed MIX spent more time feeding (174.0 vs. 139.1 min/d) and had a lower rate of intake (11.5 vs. 14.7 g/min) compared with calves fed COM. Meal frequency was similar between treatments (12.2 meals/d). Diurnal feeding patterns in wk 8 were also affected by feed presentation, with calves fed MIX spending less time feeding at time of feed delivery and more time feeding throughout the rest of the daylight hours than calves fed COM. Diurnal feeding patterns of hay and concentrate in wk 8 differed for calves fed COM, with more time spent consuming hay at time of feed delivery and less time spent consuming hay throughout the rest of the day. Once calves previously fed COM were transitioned to the MIX diet in wk 9, meal frequency, meal duration, and diurnal feeding patterns were similar between treatments: both treatments spent similar amounts of time feeding (173.9 min/d) and had similar peaks in feeding activity at time of feed delivery, sunrise, and sunset. Provision of hay and concentrate to young calves as a mixed ration, compared with separate components, increases time spent feeding and results in more evenly

  12. The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

    Science.gov (United States)

    Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; hide

    2016-01-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-meter Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 gigahertz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 gigahertz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 meter Kelvins. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 percent, a total array sensitivity of less than 10 microns Kelvin root mean square speed, and detector time constants and saturation powers suitable for ACT CMB observations.

  13. The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

    Science.gov (United States)

    Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hubmayr, J.; Koopman, B. J.; Lanen, J. V.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Ward, J. T.; Wollack, E. J.; Vavagiakis, E. M.

    2016-08-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-m Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 GHz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 GHz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 mK. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 %, a total array sensitivity of less than 10 \\upmu K√{ {s}}, and detector time constants and saturation powers suitable for ACT CMB observations.

  14. Interferometric polarization control

    International Nuclear Information System (INIS)

    Chuss, David T.; Wollack, Edward J.; Moseley, S. Harvey; Novak, Giles

    2006-01-01

    We develop the Jones and Mueller matrices for structures that allow control of the path length difference between two linear orthogonal polarizations and consider the effect of placing multiple devices in series. Specifically, we find that full polarization modulation (measurement of Stokes Q, U, and V) can be achieved by placing two such modulators in series if the relative angles of the beam-splitting grids with respect to the analyzer orientation are appropriately chosen. Such a device has several potential advantages over a spinning wave plate modulator for measuring astronomical polarization in the far infrared through millimeter: (i) The use of small, linear motions eliminates the need for cryogenic rotational bearings; (ii) the phase flexibility allows measurement of circular as well as linear polarization; and (iii) this architecture allows for both multiwavelength and broadband modulation. We also present initial laboratory results

  15. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  16. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

  17. Testing of focal plane arrays

    International Nuclear Information System (INIS)

    Merriam, J.D.

    1988-01-01

    Problems associated with the testing of focal plane arrays are briefly examined with reference to the instrumentation and measurement procedures. In particular, the approach and instrumentation used as the Naval Ocean Systems Center is presented. Most of the measurements are made with flooded illumination on the focal plane array. The array is treated as an ensemble of individual pixels, data being taken on each pixel and array averages and standard deviations computed for the entire array. Data maps are generated, showing the pixel data in the proper spatial position on the array and the array statistics

  18. Plasma polarization spectroscopy

    International Nuclear Information System (INIS)

    Iwamae, Atsushi; Horimoto, Yasuhiro; Fujimoto, Takashi; Hasegawa, Noboru; Sukegawa, Kouta; Kawachi, Tetsuya

    2005-01-01

    The electron velocity distribution function (EVDF) in plasma can be anisotropic in laser-produced plasmas. We have developed a new technique to evaluate the polarization degree of the emission lines in the extreme vacuum ultra violet wavelength region. The polarization of the emission lines and the continuums from the lithium-like nitrogen and from helium- and hydrogen-like carbon in recombining plasma is evaluated. Particle simulation in the velocity space gives the time scale for relaxation of anisotropic EVDFs. (author)

  19. No More Polarization, Please!

    OpenAIRE

    Reinholt, Mia

    2006-01-01

    The organizational science literature on motivation has for long been polarized into two main positions; the organizational economic position focusing on extrinsic motivation and the organizational behavior position emphasizing intrinsic motivation. With the rise of the knowledge economy and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on mot...

  20. Inertial polarization of dielectrics

    OpenAIRE

    Zavodovsky, A. G.

    2011-01-01

    It was proved that accelerated motion of a linear dielectric causes its polarization. Accelerated translational motion of a dielectric's plate leads to the positive charge of the surface facing the direction of motion. Metal plates of a capacitor were used to register polarized charges on a dielectric's surface. Potential difference between the capacitor plates is proportional to acceleration, when acceleration is constant potential difference grows with the increase of a dielectric's area, o...

  1. bicep2/KECK ARRAY. IV. OPTICAL CHARACTERIZATION AND PERFORMANCE OF THE bicep2 AND KECK ARRAY EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Ade, P. A. R. [School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Aikin, R. W.; Bock, J. J.; Brevik, J. A.; Filippini, J. P.; Golwala, S. R.; Hildebrandt, S. R.; Hui, H. [Department of Physics, California Institute of Technology, Pasadena, CA 91125 (United States); Barkats, D. [Joint ALMA Observatory, ESO, Santiago (Chile); Benton, S. J. [Department of Physics, University of Toronto, Toronto, ON (Canada); Bischoff, C. A.; Bradford, K. J.; Buder, I. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS 42, Cambridge, MA 02138 (United States); Bullock, E. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Dowell, C. D. [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Duband, L. [Université Grenoble Alpes, CEA INAC-SBT, F-38000 Grenoble (France); Fliescher, S. [Department of Physics, University of Minnesota, Minneapolis, MN 55455 (United States); Halpern, M.; Hasselfield, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC (Canada); Hilton, G. C., E-mail: avieregg@kicp.uchicago.edu [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Collaboration: bicep2 and Keck Array Collaborations; and others

    2015-06-20

    bicep2 and the Keck Array are polarization-sensitive microwave telescopes that observe the cosmic microwave background (CMB) from the South Pole at degree angular scales in search of a signature of inflation imprinted as B-mode polarization in the CMB. bicep2 was deployed in late 2009, observed for three years until the end of 2012 at 150 GHz with 512 antenna-coupled transition edge sensor bolometers, and has reported a detection of B-mode polarization on degree angular scales. The Keck Array was first deployed in late 2010 and will observe through 2016 with five receivers at several frequencies (95, 150, and 220 GHz). bicep2 and the Keck Array share a common optical design and employ the field-proven bicep1 strategy of using small-aperture, cold, on-axis refractive optics, providing excellent control of systematics while maintaining a large field of view. This design allows for full characterization of far-field optical performance using microwave sources on the ground. Here we describe the optical design of both instruments and report a full characterization of the optical performance and beams of bicep2 and the Keck Array at 150 GHz.

  2. Defect-Induced Hedgehog Polarization States in Multiferroics

    Science.gov (United States)

    Li, Linze; Cheng, Xiaoxing; Jokisaari, Jacob R.; Gao, Peng; Britson, Jason; Adamo, Carolina; Heikes, Colin; Schlom, Darrell G.; Chen, Long-Qing; Pan, Xiaoqing

    2018-03-01

    Continuous developments in nanotechnology require new approaches to materials synthesis that can produce novel functional structures. Here, we show that nanoscale defects, such as nonstoichiometric nanoregions (NSNRs), can act as nano-building blocks for creating complex electrical polarization structures in the prototypical multiferroic BiFeO3 . An array of charged NSNRs are produced in BiFeO3 thin films by tuning the substrate temperature during film growth. Atomic-scale scanning transmission electron microscopy imaging reveals exotic polarization rotation patterns around these NSNRs. These polarization patterns resemble hedgehog or vortex topologies and can cause local changes in lattice symmetries leading to mixed-phase structures resembling the morphotropic phase boundary with high piezoelectricity. Phase-field simulations indicate that the observed polarization configurations are mainly induced by charged states at the NSNRs. Engineering defects thus may provide a new route for developing ferroelectric- or multiferroic-based nanodevices.

  3. An analog VLSI chip emulating polarization vision of Octopus retina.

    Science.gov (United States)

    Momeni, Massoud; Titus, Albert H

    2006-01-01

    Biological systems provide a wealth of information which form the basis for human-made artificial systems. In this work, the visual system of Octopus is investigated and its polarization sensitivity mimicked. While in actual Octopus retina, polarization vision is mainly based on the orthogonal arrangement of its photoreceptors, our implementation uses a birefringent micropolarizer made of YVO4 and mounted on a CMOS chip with neuromorphic circuitry to process linearly polarized light. Arranged in an 8 x 5 array with two photodiodes per pixel, each consuming typically 10 microW, this circuitry mimics both the functionality of individual Octopus retina cells by computing the state of polarization and the interconnection of these cells through a bias-controllable resistive network.

  4. The Polarization of Achernar

    Science.gov (United States)

    McDavid, D.

    2005-11-01

    Recent near-infrared measurements of the angular diameter of Achernar (the bright Be star alpha Eridani) with the ESO VLT interferometer have been interpreted as the detection of an extremely oblate photosphere, with a ratio of equatorial to polar radius of at least 1.56 ± 0.05 and a minor axis orientation of 39° ± 1° (from North to East). The optical linear polarization of this star during an emission phase in 1995 September was 0.12 ± 0.02% at position angle 37° ± 8° (in equatorial coordinates), which is the direction of the projection of the rotation axis on the plane of the sky according to the theory of polarization by electron scattering in an equatorially flattened circumstellar disk. These two independent determinations of the orientation of the rotation axis are therefore in agreement. The observational history of correlations between Hα emission and polarization as found in the literature is that of a typical Be star, with the exception of an interesting question raised by the contrast between Schröder's measurement of a small polarization perpendicular to the projected rotation axis in 1969--70 and Tinbergen's measurement of zero polarization in 1974.5, both at times when emission was reportedly absent.

  5. Effect of feeding frequency and feeding rate on growth of ...

    African Journals Online (AJOL)

    Effect of feeding frequency and feeding rate on growth of Oreochromis mossambicus (Teleostei: Cichlidae) fry. ... Weight gain, specific growth rate and gross food conversion ratio were significantly affected by ... AJOL African Journals Online.

  6. Fusion of a polarized projectile with a polarized target

    International Nuclear Information System (INIS)

    Christley, J.A.; Johnson, R.C.; Thompson, I.J.

    1995-01-01

    The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned 165 Ho target with 16 O and polarized 7 Li beams are presented

  7. Synthesis of ordered large-scale ZnO nanopore arrays

    International Nuclear Information System (INIS)

    Ding, G.Q.; Shen, W.Z.; Zheng, M.J.; Fan, D.H.

    2006-01-01

    An effective approach is demonstrated for growing ordered large-scale ZnO nanopore arrays through radio-frequency magnetron sputtering deposition on porous alumina membranes (PAMs). The realization of highly ordered hexagonal ZnO nanopore arrays benefits from the unique properties of ZnO (hexagonal structure, polar surfaces, and preferable growth directions) and PAMs (controllable hexagonal nanopores and localized negative charges). Further evidence has been shown through the effects of nanorod size and thermal treatment of PAMs on the yielded morphology of ZnO nanopore arrays. This approach opens the possibility of creating regular semiconducting nanopore arrays for the application of filters, sensors, and templates

  8. Low-frequency synthesis array in earth orbit

    International Nuclear Information System (INIS)

    Jones, D.L.; Preston, R.A.; Kuiper, T.B.H.

    1987-01-01

    The scientific objectives and design concept of a space-based VLBI array for high-resolution astronomical observations at 1-30 MHz are discussed. The types of investigations calling for such an array include radio spectroscopy of individual objects, measurement of the effects of scattering and refraction by the interplanetary medium (IPM) and the ISM, mapping the distribution of low-energy cosmic-ray electrons, and determining the extent of the Galactic halo. Consideration is given to the limitations imposed on an LF VLBI array by the ionosphere, the IPM, and the ISM; the calibration advantages offered by circular polar orbits of slightly differing ascending-node longitude for the array satellites; and collection of the IF data streams from the array satellites by one master satellite prior to transmission to the ground. It is shown that determination of the three-dimensional array geometry by means of intersatellite radio links is feasible if there are at least seven spacecraft in the array

  9. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  10. Genetic variance components for residual feed intake and feed ...

    African Journals Online (AJOL)

    Feeding costs of animals is a major determinant of profitability in livestock production enterprises. Genetic selection to improve feed efficiency aims to reduce feeding cost in beef cattle and thereby improve profitability. This study estimated genetic (co)variances between weaning weight and other production, reproduction ...

  11. Age, lighting treatment, feed allocation and feed form influence ...

    African Journals Online (AJOL)

    During a broiler breeder trial with 3200 Cobb 500 hens, the effects of lighting treatment after 20 weeks' feed allocation and of feed form on the length of time taken to consume the daily allocation of feed were measured. Pullets were reared on 8-hour photoperiods to 20 weeks, then transferred to one of four lighting ...

  12. Prospects of complete feed system in ruminant feeding: A review

    Directory of Open Access Journals (Sweden)

    Yasir Afzal Beigh

    2017-04-01

    Full Text Available Effective utilization of available feed resources is the key for economical livestock rearing. Complete feed system is one of the latest developments to exploit the potential of animal feed resources in the best possible way. The complete feed is a quantitative mixture of all dietary ingredients, blended thoroughly to prevent separation and selection, fed as a sole source of nutrients except water and is formulated in a desired proportion to meet the specific nutrient requirements. The concentrate and roughage levels may vary according to the nutrient requirement of ruminants for different production purposes. The complete feed with the use of fibrous crop residue is a noble way to increase the voluntary feed intake and thus animal's production performance. In this system of feeding, the ruminant animals have continuous free choice availability of uniform feed mixture, resulting in more uniform load on the rumen and less fluctuation in release of ammonia which supports more efficient utilization of ruminal non-protein nitrogen. Feeding complete diet stabilizes ruminal fermentation, thereby improves nutrient utilization. This feeding system allows expanded use of agro-industrial byproducts, crop residues and nonconventional feeds in ruminant ration for maximizing production and minimizing feeding cost, thus being increasingly appreciated. However, to extend the concept extensively to the field and make this technology successful and viable for farmers, more efforts are needed to be taken.

  13. When measured spin polarization is not spin polarization

    International Nuclear Information System (INIS)

    Dowben, P A; Wu Ning; Binek, Christian

    2011-01-01

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

  14. Wideband Low Side Lobe Aperture Coupled Patch Phased Array Antennas

    Science.gov (United States)

    Poduval, Dhruva

    Low profile printed antenna arrays with wide bandwidth, high gain, and low Side Lobe Level (SLL) are in great demand for current and future commercial and military communication systems and radar. Aperture coupled patch antennas have been proposed to obtain wide impedance bandwidths in the past. Aperture coupling is preferred particularly for phased arrays because of their advantage of integration to other active devices and circuits, e.g. phase shifters, power amplifiers, low noise amplifiers, mixers etc. However, when designing such arrays, the interplay between array performance characteristics, such as gain, side lobe level, back lobe level, mutual coupling etc. must be understood and optimized under multiple design constraints, e.g. substrate material properties and thicknesses, element to element spacing, and feed lines and their orientation and arrangements with respect to the antenna elements. The focus of this thesis is to investigate, design, and develop an aperture coupled patch array with wide operating bandwidth (30%), high gain (17.5 dBi), low side lobe level (20 dB), and high Forward to Backward (F/B) ratio (21.8 dB). The target frequency range is 2.4 to 3 GHz given its wide application in WLAN, LTE (Long Term Evolution) and other communication systems. Notwithstanding that the design concept can very well be adapted at other frequencies. Specifically, a 16 element, 4 by 4 planar microstrip patch array is designed using HFSS and experimentally developed and tested. Starting from mutual coupling minimization a corporate feeding scheme is designed to achieve the needed performance. To reduce the SLL the corporate feeding network is redesigned to obtain a specific amplitude taper. Studies are conducted to determine the optimum location for a metallic reflector under the feed line to improve the F/B. An experimental prototype of the antenna was built and tested validating and demonstrating the performance levels expected from simulation predictions

  15. Wire Array Photovoltaics

    Science.gov (United States)

    Turner-Evans, Dan

    Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar. Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry. The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires. Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction

  16. Status and Integrated Focal Plane Characterization of Simons Array - Cosmic Microwave Background Polarimetry Experiment

    Science.gov (United States)

    Roberts, Hayley; POLARBEAR

    2018-06-01

    Simons Array is a cosmic microwave background (CMB) polarization experiment located at 5,200 meter altitude site in the Atacama desert in Chile. The science goals of the Simons Array are to characterize the CMB B-mode signal from gravitational lensing, and search for B-mode polarization generated from inflationary gravitational waves.In 2012, POLARBEAR-1 (PB-1) began observations and the POLARBEAR team has published the first measurements of non-zero polarization B-mode polarization angular power spectrum where gravitational lensing of CMB is the dominant signal.POLARBEAR-2A (PB-2A), the first of three receivers of Simons Array, will have 7,588 polarization sensitive Transition Edge Sensor (TES) bolometers with frequencies 90 GHz and 150 GHz. This represents a factor of 6 increase in detector count compared to PB-1. Once Simons Array is fully deployed, the focal plane array will consist 22,764 TES bolometers across 90 GHz, 150 GHz, 220 GHz, and 270 GHz with a projected instantaneous sensitivity of 2.5 µK√s. Here we present the status of PB-2A and characterization of the integrated focal plane to be deployed summer of 2018.

  17. The evolution of tensor polarization

    International Nuclear Information System (INIS)

    Huang, H.; Lee, S.Y.; Ratner, L.

    1993-01-01

    By using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization, the spin transfer matrix for spin tensor polarization is derived. The evolution equation for the tensor polarization is studied in the presence of an isolate spin resonance and in the presence of a spin rotor, or snake

  18. The polarization of fast neutrons

    International Nuclear Information System (INIS)

    Talov, V.V.

    2000-01-01

    The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li(p,n) 7 Be, and T(p,n) 3 He reactions. (authors)

  19. Seawater feed reverse osmosis preheating appraisal, Part I: leading element performance

    International Nuclear Information System (INIS)

    Karameldin, A.; Saadawy, M.S.

    2006-01-01

    This paper is concerned with the seawater reverse osmosis preheating process, and presents a parametric study of the process. The basic transport equations describing the leading element are exhibited and appraised. The leading element, which governs the whole system performance, is studied and analysed. The incorporated and investigated operating parameters are the feed pressure and the temperature for different feed salt concentrations. In addition, different feed flow rates, effects on permeate flux and permeator salt rejection, together with the permeator recovery, are studied. A seawater membrane of a well-known data, for instance FT30SW380HR, is used to perform the study. The membrane water permeability coefficient K w is determined and correlated. Furthermore, the membrane salt permeability coefficient K s from the manufacturer system analysis program (ROSA) is given and discussed. The transport governing equations are programmed in a way that facilitates the achievement of a realistic parametric study. The results showed that the permeate flux increases significantly as the feed pressure increases. Also, it increases significantly as the feed salt concentration decreases, and also as the feed temperature and pressure increase. Meanwhile, the permeator salt rejection increases significantly as the feed pressure increases, and decreases significantly as the feed temperature increases. The study of the leading element of the array showed that there are constraints that must be considered, such as maximum membrane flux, maximum applied feed pressure, maximum feed flow rate and maximum feed temperature. Therefore, to attain the maximum membrane flux, the applied feed pressure must be lowered when the feed temperature is increased. In the case where the feed temperature is increased from 18 deg.. C to 45 deg.. C, a pressure saving of between 7% and 26% is achieved, according to the feed salt concentration and feed flow rate. (author)

  20. The Submillimeter Polarization of Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Marrone, Daniel P [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Moran, James M [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Rao, Ramprasad [Inst. of Ast. and Astrophys., Academia Sinica, PO Box 23-141, Taipei 10617, Taiwan (China)

    2006-12-15

    We report on the submillimeter properties of Sgr A* derived from observations with the Submillimeter Array and its polarimeter. We ftid that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured simultaneously, indicating a transition to optically thin emission around 300-400 GHz. We also present very sensitive and well calibrated measurements of the polarization of Sgr A* at 230 and 345 GHz. With these data we are able to show for the frst time that the polarization of Sgr A* varies on hour timescales, as has been observed for the total intensity. On one night we fhd variability that may arise from a polarized 'blob' orbiting the black hole. Finally, we use the ensemble of observations to determine the rotation measure. This represents the frst statistically significant rotation measure determination and the only one made without resorting to comparing position angles measured at separate epochs. We frid a rotation measure of (-5.6 {+-} 0.7) x 10{sup 5} rad m{sup 2}, with no evidence for variability on inter-day timescales at the level of the measurement error. The stability constrains interday flictuations in the accretion rate to 8%. The mean intrinsic polarization position angle is 167{sup 0}{+-}7{sup 0} and we detect variations of 31{sup +18}{sub -9} degrees. This separation of intrinsic polarization changes and possible rotation measure flictuations is now possible because of the frequency coverage and sensitivity of our data. The observable rotation measure restricts the accretion rate to the range 2 x 10{sup -7} M o-dot yr{sup -1} to 2 x 10{sup -9} M o-dot yr{sup -1}, if the magnetic field is near equipartition and ordered.

  1. The Submillimeter Polarization of Sgr A*

    International Nuclear Information System (INIS)

    Marrone, Daniel P; Moran, James M; Zhao, Jun-Hui; Rao, Ramprasad

    2006-01-01

    We report on the submillimeter properties of Sgr A* derived from observations with the Submillimeter Array and its polarimeter. We ftid that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured simultaneously, indicating a transition to optically thin emission around 300-400 GHz. We also present very sensitive and well calibrated measurements of the polarization of Sgr A* at 230 and 345 GHz. With these data we are able to show for the frst time that the polarization of Sgr A* varies on hour timescales, as has been observed for the total intensity. On one night we fhd variability that may arise from a polarized 'blob' orbiting the black hole. Finally, we use the ensemble of observations to determine the rotation measure. This represents the frst statistically significant rotation measure determination and the only one made without resorting to comparing position angles measured at separate epochs. We frid a rotation measure of (-5.6 ± 0.7) x 10 5 rad m 2 , with no evidence for variability on inter-day timescales at the level of the measurement error. The stability constrains interday flictuations in the accretion rate to 8%. The mean intrinsic polarization position angle is 167 0 ±7 0 and we detect variations of 31 +18 -9 degrees. This separation of intrinsic polarization changes and possible rotation measure flictuations is now possible because of the frequency coverage and sensitivity of our data. The observable rotation measure restricts the accretion rate to the range 2 x 10 -7 M o-dot yr -1 to 2 x 10 -9 M o-dot yr -1 , if the magnetic field is near equipartition and ordered

  2. The Submillimeter Polarization of Sgr A*

    Science.gov (United States)

    Marrone, Daniel P.; Moran, James M.; Zhao, Jun-Hui; Rao, Ramprasad

    2006-12-01

    We report on the submillimeter properties of Sgr A* derived from observations with the Submillimeter Array and its polarimeter. We ftid that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured simultaneously, indicating a transition to optically thin emission around 300 400 GHz. We also present very sensitive and well calibrated measurements of the polarization of Sgr A* at 230 and 345 GHz. With these data we are able to show for the frst time that the polarization of Sgr A* varies on hour timescales, as has been observed for the total intensity. On one night we fhd variability that may arise from a polarized "blob" orbiting the black hole. Finally, we use the ensemble of observations to determine the rotation measure. This represents the frst statistically significant rotation measure determination and the only one made without resorting to comparing position angles measured at separate epochs. We frid a rotation measure of (-5.6 ± 0.7) × 105 rad m2, with no evidence for variability on inter-day timescales at the level of the measurement error. The stability constrains interday flictuations in the accretion rate to 8%. The mean intrinsic polarization position angle is 167°±7° and we detect variations of 31+18-9 degrees. This separation of intrinsic polarization changes and possible rotation measure flictuations is now possible because of the frequency coverage and sensitivity of our data. The observable rotation measure restricts the accretion rate to the range 2 × 10-7 Mdot o yr-1 to 2 × 10-9 Mdot o yr-1, if the magnetic ffeld is near equipartition and ordered.

  3. The Primordial Inflation Polarization Explorer (PIPER)

    Science.gov (United States)

    Lazear, Justin Scott; Ade, Peter A.; Benford, Dominic J.; Bennett, Charles L.; Chuss, David T.; Dotson, Jessie L.; Eimer, Joseph R.; Fixsen, Dale J.; Halpern, Mark; Hinderks, James; hide

    2014-01-01

    The Primordial Inflation Polarization ExploreR (Piper) is a balloon-borne cosmic microwave background (CMB) polarimeter designed to search for evidence of inflation by measuring the large-angular scale CMB polarization signal. Bicep2 recently reported a detection of B-mode power corresponding to the tensor-to-scalar ratio r = 0.2 on approximately 2 degree scales. If the Bicep2 signal is caused by inflationary gravitational waves (IGWs), then there should be a corresponding increase in B-mode power on angular scales larger than 18 degrees. Piper is currently the only suborbital instrument capable of fully testing and extending the Bicep2 results by measuring the B-mode power spectrum on angular scales theta ? = approximately 0.6 deg to 90 deg, covering both the reionization bump and recombination peak, with sensitivity to measure the tensor-to-scalar ratio down to r = 0.007, and four frequency bands to distinguish foregrounds. Piper will accomplish this by mapping 85% of the sky in four frequency bands (200, 270, 350, 600 GHz) over a series of 8 conventional balloon flights from the northern and southern hemispheres. The instrument has background-limited sensitivity provided by fully cryogenic (1.5 K) optics focusing the sky signal onto four 32×40-pixel arrays of time-domain multiplexed Transition-Edge Sensor (TES) bolometers held at 140 milli-Kelvin. Polarization sensitivity and systematic control are provided by front-end Variabledelay Polarization Modulators (VPMs), which rapidly modulate only the polarized sky signal at 3 Hz and allow Piper to instantaneously measure the full Stokes vector (I,Q,U,0V) for each pointing. We describe the Piper instrument and progress towards its first flight.

  4. Polarized particles in storage rings

    International Nuclear Information System (INIS)

    Derbenev, Ya.S.; Kondratenko, A.M.; Serednyakov, S.I.; Skrinskij, A.N.; Tumajkin, G.M.; Shatunov, Yu.M.

    1977-01-01

    Experiments with polarized beams on the VEPP-2M and SPEAK storage rings are described. Possible methods of producing polarized particle beams in storage rings as well as method of polarization monitoring are counted. Considered are the processes of radiation polarization of electrons and positrons. It is shown, that to preserve radiation polarization the introduction of regions with a strong sign-variable magnetic field is recommended. Methods of polarization measurement are counted. It is suggested for high energies to use dependence of synchrotron radiation power on transverse polarization of electrons and positrons. Examples of using polarizability of colliding beams in storage rings are presented

  5. Feed the dogs

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark; Bajde, Domen

    2016-01-01

    MedieKultur | Journal of media and communication research | ISSN 1901-9726Article – Open sectionPublished by SMID | Society of Media researchers In Denmark | www.smid.dkTh e online version of this text can be found open access at www.mediekultur.dk196Feed the dogsA case of humanitarian communicat......MedieKultur | Journal of media and communication research | ISSN 1901-9726Article – Open sectionPublished by SMID | Society of Media researchers In Denmark | www.smid.dkTh e online version of this text can be found open access at www.mediekultur.dk196Feed the dogsA case of humanitarian...

  6. Radiation technology and feed production

    International Nuclear Information System (INIS)

    Ershov, B.G.

    1986-01-01

    The use of radiation technology to prepare feeds and feed additions for cattle of non-feed vegetable blends is considered.Physicochemical foundations of radiation-chemical processes, possibilities of the use of various radiation devices are given. Data on practical realization of the technology are presented and prospects of its introduction to solve the tasks put forward by the USSR program on feed production are analyzed

  7. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    Sinclair, C.K.

    1998-01-01

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented. copyright 1998 American Institute of Physics

  8. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

  9. Polarization: A Must for Fusion

    Directory of Open Access Journals (Sweden)

    Guidal M.

    2012-10-01

    Full Text Available Recent realistic simulations confirm that the polarization of the fuel would improve significantly the DT fusion efficiency. We have proposed an experiment to test the persistence of the polarization in a fusion process, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the neutrons and the change in the corresponding total cross section are related to the polarization persistence. The experimental polarization of DT fuel is a technological challenge. Possible paths for Magnetic Confinement Fusion (MCF and for Inertial Confinement Fusion (ICF are reviewed. For MCF, polarized gas can be used. For ICF, cryogenic targets are required. We consider both, the polarization of gas and the polarization of solid DT, emphasizing the Dynamic Nuclear polarization (DNP of HD and DT molecules.

  10. Feed sources for livestock

    OpenAIRE

    Zanten, van, H.H.E.

    2016-01-01

    Production of food has re-emerged at the top of the global political agenda, driven by two contemporary challenges: the challenge to produce enough nutritious food to feed a growing and more prosperous human population, and the challenge to produce this food in an environmentally sustainable way. Current levels of production of especially animal-source food (ASF), pose severe pressure on the environment via their emissions to air, water, and soil; and their use of scarce resources, such as la...

  11. A review of array radars

    Science.gov (United States)

    Brookner, E.

    1981-10-01

    Achievements in the area of array radars are illustrated by such activities as the operational deployment of the large high-power, high-range-resolution Cobra Dane; the operational deployment of two all-solid-state high-power, large UHF Pave Paws radars; and the development of the SAM multifunction Patriot radar. This paper reviews the following topics: array radars steered in azimuth and elevation by phase shifting (phase-phase steered arrays); arrays steered + or - 60 deg, limited scan arrays, hemispherical coverage, and omnidirectional coverage arrays; array radars steering electronically in only one dimension, either by frequency or by phase steering; and array radar antennas which use no electronic scanning but instead use array antennas for achieving low antenna sidelobes.

  12. Variety of Polarized Line Profiles in Interacting Supernovae

    Science.gov (United States)

    Hoffman, Jennifer L.; Huk, L. N.; Peters, C. L.

    2013-01-01

    The dense circumstellar material that creates strong emission lines in the spectra of interacting supernovae also gives rise to complex line polarization behavior. Viewed in polarized light, the emission line profiles of these supernovae encode information about the geometrical and optical characteristics of their surrounding circumstellar material (CSM) that is inaccessible by other observational techniques. To facilitate quantitative interpretation of these spectropolarimetric signatures, we have created a large grid of model polarized line profiles using a three-dimensional radiative transfer code that simulates polarization via electron and resonant/fluorescent line scattering. The simulated polarized lines take on an array of profile shapes that vary with viewing angle and CSM properties. We present the major results from the grid and investigate the dependence of polarized line profiles on CSM characteristics including temperature, optical depth, and geometry. These results will allow more straightforward interpretation of polarized line profiles in interacting supernovae than has previously been possible. This research is supported by the National Science Foundation through the AAG program and the XSEDE collaboration, and uses the resources of the Texas Advanced Computing Center.

  13. Emerging issues in complementary feeding

    DEFF Research Database (Denmark)

    Michaelsen, Kim F.; Grummer-Strawn, Laurence; Bégin, France

    2017-01-01

    the complementary feeding period is summarized. The increased availability of sugar-containing beverages and unhealthy snack foods and its negative effect on young child's diet is described. Negative effects of nonresponsive feeding and force feeding are also discussed, although few scientific studies have...

  14. Enteral feeding without pancreatic stimulation

    DEFF Research Database (Denmark)

    Kaushik, Neeraj; Pietraszewski, Marie; Holst, Jens Juul

    2005-01-01

    OBJECTIVE: All forms of commonly practiced enteral feeding techniques stimulate pancreatic secretion, and only intravenous feeding avoids it. In this study, we explored the possibility of more distal enteral infusions of tube feeds to see whether activation of the ileal brake mechanism can result...

  15. The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

    Science.gov (United States)

    Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angile, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.; hide

    2016-01-01

    The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3deg field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev-Zel'dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

  16. The Atacama Cosmology Telescope: The Polarization-sensitive ACTPol Instrument

    Science.gov (United States)

    Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angilè, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.; Coughlin, K. P.; Datta, R.; Devlin, M. J.; Dicker, S. R.; Dünner, R.; Fowler, J. W.; Fox, A. E.; Gallardo, P. A.; Gao, J.; Grace, E.; Halpern, M.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hincks, A. D.; Ho, S. P.; Hubmayr, J.; Irwin, K. D.; Klein, J.; Koopman, B.; Li, Dale; Louis, T.; Lungu, M.; Maurin, L.; McMahon, J.; Munson, C. D.; Naess, S.; Nati, F.; Newburgh, L.; Nibarger, J.; Niemack, M. D.; Niraula, P.; Nolta, M. R.; Page, L. A.; Pappas, C. G.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sievers, J. L.; Simon, S. M.; Staggs, S. T.; Tucker, C.; Uehara, M.; van Lanen, J.; Ward, J. T.; Wollack, E. J.

    2016-12-01

    The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3° field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev–Zel’dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

  17. SUBMILLIMETER POLARIZATION OBSERVATION OF THE PROTOPLANETARY DISK AROUND HD 142527

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, Akimasa; Dullemond, Cornelis P.; Pohl, Adriana [Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Tsukagoshi, Takashi; Momose, Munetake [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan); Nagai, Hiroshi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Muto, Takayuki [Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677 (Japan); Fukagawa, Misato [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Shibai, Hiroshi [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Hanawa, Tomoyuki [Center for Frontier Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522 (Japan); Murakawa, Koji, E-mail: kataoka@uni-heidelberg.de [College of General Education, Osaka Sangyo University, 3-1-1, Nakagaito, Daito, Osaka 574-8530 (Japan)

    2016-11-10

    We present the polarization observations toward the circumstellar disk around HD 142527 by using Atacama Large Millimeter/submillimeter Array at the frequency of 343 GHz. The beam size is 0.″51 × 0.″44, which corresponds to the spatial resolution of ∼71 × 62 au. The polarized intensity displays a ring-like structure with a peak located on the east side with a polarization fraction of P = 3.26 ± 0.02%, which is different from the peak of the continuum emission from the northeast region. The polarized intensity is significantly weaker at the peak of the continuum where P = 0.220 ± 0.010%. The polarization vectors are in the radial direction in the main ring of the polarized intensity, while there are two regions outside at the northwest and northeast areas where the vectors are in the azimuthal direction. If the polarization vectors represent the magnetic field morphology, the polarization vectors indicate the toroidal magnetic field configuration on the main ring and the poloidal fields outside. On the other hand, the flip of the polarization vectors is predicted by the self-scattering of thermal dust emission due to the change of the direction of thermal radiation flux. Therefore, we conclude that self-scattering of thermal dust emission plays a major role in producing polarization at millimeter wavelengths in this protoplanetary disk. Also, this puts a constraint on the maximum grain size to be approximately 150 μ m if we assume compact spherical dust grains.

  18. Study by polarized muon

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu

    1977-01-01

    Experiments by using polarized muon beam are reported. The experiments were performed at Berkeley, U.S.A., and at Vancouver, Canada. The muon spin rotation is a useful method for the study of the spin polarization of conductive electrons in paramagnetic Pd metal. The muon Larmor frequency and the relaxation time can be obtained by measuring the time distribution of decay electrons of muon-electron process. The anomalous depolarization of negative muon spin rotation in the transitional metal was seen. The circular polarization of the negative muon X-ray was measured to make clear this phenomena. The experimental results show that the anomalous depolarization is caused at the 1-S-1/2 state. For the purpose to obtain the strong polarization of negative muon, a method of artificial polarization is proposed, and the test experiments are in progress. The study of the hyperfine structure of mu-mesic atoms is proposed. The muon capture rate was studied systematically. (Kato, T.)

  19. Polarized protons at RHIC

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1990-12-01

    The Physics case is presented for the use of polarized protons at RHIC for one or two months each year. This would provide a facility with polarizations of approx-gt 50% high luminosity ∼2.0 x 10 32 cm -2 s -1 , the possibility of both longitudinal and transverse polarization at the interaction regions, and frequent polarization reversal for control of systematic errors. The annual integrated luminosity for such running (∼10 6 sec per year) would be ∫ Ldt = 2 x 10 38 cm -2 -- roughly 20 times the total luminosity integrated in ∼ 10 years of operation of the CERN Collider (∼10 inverse picobarns, 10 37 cm -2 ). This facility would be unique in the ability to perform parity-violating measurements and polarization test of QCD. Also, the existence of p-p collisions in a new energy range would permit the study of ''classical'' reactions like the total cross section and elastic scattering, etc., and serve as a complement to measurements from p-bar p colliders. 11 refs

  20. The Bochum Polarized Target

    International Nuclear Information System (INIS)

    Reicherz, G.; Goertz, S.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Radtke, E.

    2001-01-01

    The Bochum 'Polarized Target' group develops the target material 6 LiD for the COMPASS experiment at CERN. Several different materials like alcohols, alcanes and ammonia are under investigation. Solid State Targets are polarized in magnetic fields higher than B=2.5T and at temperatures below T=1K. For the Dynamic Nuclear Polarization process, paramagnetic centers are induced chemically or by irradiation with ionizing beams. The radical density is a critical factor for optimization of polarization and relaxation times at adequate magnetic fields and temperatures. In a high sensitive EPR--apparatus, an evaporator and a dilution cryostat with a continuous wave NMR--system, the materials are investigated and optimized. To improve the polarization measurement, the Liverpool NMR-box is modified by exchanging the fixed capacitor for a varicap diode which not only makes the tuning very easy but also provides a continuously tuned circuit. The dependence of the signal area upon the circuit current is measured and it is shown that it follows a linear function

  1. Overview of FEED, the feeding experiments end-user database.

    Science.gov (United States)

    Wall, Christine E; Vinyard, Christopher J; Williams, Susan H; Gapeyev, Vladimir; Liu, Xianhua; Lapp, Hilmar; German, Rebecca Z

    2011-08-01

    The Feeding Experiments End-user Database (FEED) is a research tool developed by the Mammalian Feeding Working Group at the National Evolutionary Synthesis Center that permits synthetic, evolutionary analyses of the physiology of mammalian feeding. The tasks of the Working Group are to compile physiologic data sets into a uniform digital format stored at a central source, develop a standardized terminology for describing and organizing the data, and carry out a set of novel analyses using FEED. FEED contains raw physiologic data linked to extensive metadata. It serves as an archive for a large number of existing data sets and a repository for future data sets. The metadata are stored as text and images that describe experimental protocols, research subjects, and anatomical information. The metadata incorporate controlled vocabularies to allow consistent use of the terms used to describe and organize the physiologic data. The planned analyses address long-standing questions concerning the phylogenetic distribution of phenotypes involving muscle anatomy and feeding physiology among mammals, the presence and nature of motor pattern conservation in the mammalian feeding muscles, and the extent to which suckling constrains the evolution of feeding behavior in adult mammals. We expect FEED to be a growing digital archive that will facilitate new research into understanding the evolution of feeding anatomy.

  2. Impact of biofilm accumulation on transmembrane and feed channel pressure drop: Effects of crossflow velocity, feed spacer and biodegradable nutrient

    KAUST Repository

    Dreszer, C.

    2014-03-01

    Biofilm formation causes performance loss in spiral-wound membrane systems. In this study a microfiltration membrane was used in experiments to simulate fouling in spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules without the influence of concentration polarization. The resistance of a microfiltration membrane is much lower than the intrinsic biofilm resistance, enabling the detection of biofilm accumulation in an early stage. The impact of biofilm accumulation on the transmembrane (biofilm) resistance and feed channel pressure drop as a function of the crossflow velocity (0.05 and 0.20ms-1) and feed spacer presence was studied in transparent membrane biofouling monitors operated at a permeate flux of 20Lm-2h-1. As biodegradable nutrient, acetate was dosed to the feed water (1.0 and 0.25mgL-1 carbon) to enhance biofilm accumulation in the monitors. The studies showed that biofilm formation caused an increased transmembrane resistance and feed channel pressure drop. The effect was strongest at the highest crossflow velocity (0.2ms-1) and in the presence of a feed spacer. Simulating conditions as currently applied in nanofiltration and reverse osmosis installations (crossflow velocity 0.2ms-1 and standard feed spacer) showed that the impact of biofilm formation on performance, in terms of transmembrane and feed channel pressure drop, was strong. This emphasized the importance of hydrodynamics and feed spacer design. Biomass accumulation was related to the nutrient load (nutrient concentration and linear flow velocity). Reducing the nutrient concentration of the feed water enabled the application of higher crossflow velocities. Pretreatment to remove biodegradable nutrient and removal of biomass from the membrane elements played an important part to prevent or restrict biofouling. © 2013 Elsevier Ltd.

  3. Detector array and method

    International Nuclear Information System (INIS)

    Timothy, J.G.; Bybee, R.L.

    1978-01-01

    A detector array and method are described in which sets of electrode elements are provided. Each set consists of a number of linear extending parallel electrodes. The sets of electrode elements are disposed at an angle (preferably orthogonal) with respect to one another so that the individual elements intersect and overlap individual elements of the other sets. Electrical insulation is provided between the overlapping elements. The detector array is exposed to a source of charged particles which in accordance with one embodiment comprise electrons derived from a microchannel array plate exposed to photons. Amplifier and discriminator means are provided for each individual electrode element. Detection means are provided to sense pulses on individual electrode elements in the sets, with coincidence of pulses on individual intersecting electrode elements being indicative of charged particle impact at the intersection of the elements. Electronic readout means provide an indication of coincident events and the location where the charged particle or particles impacted. Display means are provided for generating appropriate displays representative of the intensity and locaton of charged particles impacting on the detector array

  4. Diode lasers and arrays

    International Nuclear Information System (INIS)

    Streifer, W.

    1988-01-01

    This paper discusses the principles of operation of III-V semiconductor diode lasers, the use of distributed feedback, and high power laser arrays. The semiconductor laser is a robust, miniature, versatile device, which directly converts electricity to light with very high efficiency. Applications to pumping solid-state lasers and to fiber optic and point-to-point communications are reviewed

  5. Array Theory and Nial

    DEFF Research Database (Denmark)

    Falster, Peter; Jenkins, Michael

    1999-01-01

    This report is the result of collaboration between the authors during the first 8 months of 1999 when M. Jenkins was visiting professor at DTU. The report documents the development of a tool for the investigation of array theory concepts and in particular presents various approaches to choose...

  6. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo; Conchouso Gonzalez, David; Castro, David; Kosel, Jü rgen; Foulds, Ian G.

    2016-01-01

    contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT

  7. The anatomy of a radio source hot spot : Very large baseline array imaging of 3C 205

    NARCIS (Netherlands)

    Lonsdale, CJ; Barthel, PD

    Total intensity and linear polarization Very Long Baseline Array (VLBA) images of the high-redshift quasar 3C 205 at a wavelength of 18 cm reveal a complex curved hot-spot structure with polarization percentages frequently as high as 70%. A one-sided jet is detected emerging from the central

  8. The importance of live-feed traps - farming marine fish species

    DEFF Research Database (Denmark)

    Nielsen, Rasmus; Nielsen, Max; Abate, Tenaw Gedefaw

    2017-01-01

    This article analyses the challenges of different live-feed regimes for the rearing of marine finfish larvae and discusses the potential alternative live feeds to avert a future live-feed trap. Live feeds are indispensable for the successful rearing of larvae of most marine fish species. Brine...... shrimps (Artemia) and rotifers comprise the live feeds of choice in marine aquaculture today. However, their nutritional composition is deficient in especially essential fatty acids, and enrichment with fish oil is needed. Fish oil is considered a limited resource owing to its origin in fully exploited...... wild fish stocks. Moreover, fluctuations of the natural population of Artemia will, most likely, influence future availability and prices. This emphasizes the need for optimal exploitation of available live-feed resources and development of new sustainable alternatives, such as copepods. An array...

  9. Polarized source upgrading

    International Nuclear Information System (INIS)

    Clegg, T.B.; Rummel, R.L.; Carter, E.P.; Westerfeldt, C.R.; Lovette, A.W.; Edwards, S.E.

    1985-01-01

    The decision was made this past year to move the Lamb-shift polarized ion source which was first installed in the laboratory in 1970. The motivation was the need to improve the flexibility of spin-axis orientation by installing the ion source with a new Wien-filter spin precessor which is capable of rotating physically about the beam axis. The move of the polarized source was accomplished in approximately two months, with the accelerator being turned off for experiments during approximately four weeks of this time. The occasion of the move provided the opportunity to rewire completely the entire polarized ion source frame and to rebuild approximately half of the electronic chassis on the source. The result is an ion source which is now logically wired and carefully documented. Beams obtained from the source are much more stable than those previously available

  10. Spin polarized deuterium

    International Nuclear Information System (INIS)

    Glyde, H.R.; Hernadi, S.I.

    1986-01-01

    Several ground state properties of (electron) spin-polarized deuterium (D) such as the energy, single quasiparticle energies and lifetimes, Landau parameters and sound velocities are evaluated. The calculations begin with the Kolos-Wolneiwicz potential and use the Galitskii-FeynmanHartree-Fock (GFHF) approximation. The deuteron nucleas has spin I = 1, and spin states I/sub z/ = 1,0,-1. We explore D 1 , D 2 and D 3 in which, respectively, one spin state only is populated, two states are equally populated, and three states are equally populated. We find the GFHF describes D 1 well, but D 2 and D 3 less well. The Landau parameters, F/sub L/, are small compared to liquid 3 He and very small for doubly polarized D 1 (i.e. the F/sub L/ decrease with nuclear polarization)

  11. Polarized electron sources

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1995-05-01

    Polarized electron sources for high energy accelerators took a significant step forward with the introduction of a new laser-driven photocathode source for the SLC in 1992. With an electron beam polarization of >80% and with ∼99% uptime during continuous operation, this source is a key factor in the success of the current SLC high-energy physics program. The SLC source performance is used to illustrate both the capabilities and the limitations of solid-state sources. The beam requirements for future colliders are similar to that of the SLC with the addition in most cases of multiple-bunch operation. A design for the next generation accelerator source that can improve the operational characteristics and at least minimize some of the inherent limitations of present sources is presented. Finally, the possibilities for producing highly polarized electron beams for high-duty-factor accelerators are discussed

  12. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......, to reconstruct the distribution of the Cole-Cole parameters of the earth. The accurate modeling of the transmitter waveform had a strong influence on the forward response, and we showed that the difference between a solution using a step response and a solution using the accurate modeling often is above 100...

  13. A lunar polar expedition

    Science.gov (United States)

    Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

    1992-09-01

    Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

  14. Modelling Polar Self Assembly

    Science.gov (United States)

    Olvera de La Cruz, Monica; Sayar, Mehmet; Solis, Francisco J.; Stupp, Samuel I.

    2001-03-01

    Recent experimental studies in our group have shown that self assembled thin films of noncentrosymmetric supramolecular objects composed of triblock rodcoil molecules exhibit finite polar order. These aggregates have both long range dipolar and short range Ising-like interactions. We study the ground state of a simple model with these competing interactions. We find that the competition between Ising-like and dipolar forces yield a periodic domain structure, which can be controlled by adjusting the force constants and film thickness. When the surface forces are included in the potential, the system exhibits a finite macroscopic polar order.

  15. AGS polarized H- source

    International Nuclear Information System (INIS)

    Kponou, A.; Alessi, J.G.; Sluyters, T.

    1985-01-01

    The AGS polarized H - source is now operational. During a month-long experimental physics run in July 1984, pulses equivalent to 15 μA x 300 μs (approx. 3 x 10 10 protons) were injected into the RFQ preaccelerator. Beam polarization, measured at 200 MeV, was approx. 75%. After the run, a program to increase the H - yield of the source was begun and significant progress has been made. The H - current is now frequently 20 to 30 μA. A description of the source and some details of our operating experience are given. We also briefly describe the improvement program

  16. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

    The mesosphere region, which lies at the edge of space, contains the coldest layer of the Earth's atmosphere, with summer temperatures as low as minus 130 °C. In this extreme environment ice aerosol layers have appeared since the dawn of industrialization—whose existence may arguably be linked to human influence—on yet another layer of the Earth's fragile atmosphere. Ground-based and space-based experiments conducted in the Arctic and Antarctic during the International Polar Year (IPY) aim to address limitations in our knowledge and to advance our understanding of thermal and dynamical processes at play in the polar mesosphere

  17. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

    Full Text Available Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The method is based on the spatially resolved measurement of the cumulative precession angles of a collimated, polarized, monochromatic neutron beam that traverses a magnetic field or sample.

  18. Polarization splitter and polarization rotator designs based on transformation optics.

    Science.gov (United States)

    Kwon, Do-Hoon; Werner, Douglas H

    2008-11-10

    The transformation optics technique is employed in this paper to design two optical devices - a two-dimensional polarization splitter and a three-dimensional polarization rotator for propagating beams. The polarization splitter translates the TM- and the TE-polarized components of an incident beam in opposite directions (i.e., shifted up or shifted down). The polarization rotator rotates the polarization state of an incoming beam by an arbitrary angle. Both optical devices are reflectionless at the entry and exit interfaces. Design details and full-wave simulation results are provided.

  19. Superconducting Undulator with Variably Polarized Light

    CERN Document Server

    Hwang, Ching Shiang; Ching Fan, Tai; Li, W P; Lin, P H

    2004-01-01

    This study investigates planar in-vacuo superconducting undulators with periodic length of 5 cm (IVSU5) producing linearly and circularly polarized infrared rays or xrays source. The vertically wound racetrack coil is selected for the coil and pole fabrication of the IVSU5. When the up and down magnetic pole arrays with alternative directions rotated wires in the horizontal plane, a helical field radiates circularly polarized light in the electron storage ring, the free electron laser (FEL), and the energy recovery linac (ERL) facilities. Meanwhile, an un-rotated wire is constructed together with the rotated wire on the same undulator is used to switch the linear horizontal and vertical, the right- and left-circular polarization radiation. Given a periodic length of 5 cm and a gap of 23 mm, the maximum magnetic flux density in the helical undulator are Bz = 1.5 T and Bx = 0.5 T when the wires rotated by 20°. This article describes the main factors of the planar and helical undulator design for FEL and...

  20. First feeding of larval herring

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter; Støttrup, Josianne

    1985-01-01

    The transition period from endogenous to exogenous feeding by larval herring was investigated in the laboratory for four herring stocks in order to evaluate the chances of survival at the time of fiest feeding. Observations on larval activity, feeding and growth were related to amount of yolk......, visual experience with potential prey organisms prior to first feeding and prey density. Herring larvae did not initiate exogenous feeding until around the time of yolk resorption. The timing of first feeding was not influenced by prior exposure to potential prey organisms during the yolk sac stage....... In the light of these observations, the ecological significance of the yolk sac stage is discussed. Initiation of exogenous feeding was delayed by 1-4 days at a low (7.5 nauplii .cntdot. l-1) compared to a high (120 nauplii .cntdot. l-1) prey density, but even at prey densities corresponding to the lower end...

  1. Polarized Proton Collisions at RHIC

    CERN Document Server

    Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

    2005-01-01

    The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

  2. Polarization diversity scheme on spectral polarization coding optical code-division multiple-access network

    Science.gov (United States)

    Yen, Chih-Ta; Huang, Jen-Fa; Chang, Yao-Tang; Chen, Bo-Hau

    2010-12-01

    We present an experiment demonstrating the spectral-polarization coding optical code-division multiple-access system introduced with a nonideal state of polarization (SOP) matching conditions. In the proposed system, the encoding and double balanced-detection processes are implemented using a polarization-diversity scheme. Because of the quasiorthogonality of Hadamard codes combining with array waveguide grating routers and a polarization beam splitter, the proposed codec pair can encode-decode multiple code words of Hadamard code while retaining the ability for multiple-access interference cancellation. The experimental results demonstrate that when the system is maintained with an orthogonal SOP for each user, an effective reduction in the phase-induced intensity noise is obtained. The analytical SNR values are found to overstate the experimental results by around 2 dB when the received effective power is large. This is mainly limited by insertion losses of components and a nonflattened optical light source. Furthermore, the matching conditions can be improved by decreasing nonideal influences.

  3. Concurrent array-based queue

    Science.gov (United States)

    Heidelberger, Philip; Steinmacher-Burow, Burkhard

    2015-01-06

    According to one embodiment, a method for implementing an array-based queue in memory of a memory system that includes a controller includes configuring, in the memory, metadata of the array-based queue. The configuring comprises defining, in metadata, an array start location in the memory for the array-based queue, defining, in the metadata, an array size for the array-based queue, defining, in the metadata, a queue top for the array-based queue and defining, in the metadata, a queue bottom for the array-based queue. The method also includes the controller serving a request for an operation on the queue, the request providing the location in the memory of the metadata of the queue.

  4. A Fast DOA Estimation Algorithm Based on Polarization MUSIC

    Directory of Open Access Journals (Sweden)

    R. Guo

    2015-04-01

    Full Text Available A fast DOA estimation algorithm developed from MUSIC, which also benefits from the processing of the signals' polarization information, is presented. Besides performance enhancement in precision and resolution, the proposed algorithm can be exerted on various forms of polarization sensitive arrays, without specific requirement on the array's pattern. Depending on the continuity property of the space spectrum, a huge amount of computation incurred in the calculation of 4-D space spectrum is averted. Performance and computation complexity analysis of the proposed algorithm is discussed and the simulation results are presented. Compared with conventional MUSIC, it is indicated that the proposed algorithm has considerable advantage in aspects of precision and resolution, with a low computation complexity proportional to a conventional 2-D MUSIC.

  5. Wideband feeds for the upgraded GMRT

    International Nuclear Information System (INIS)

    Bandari, Hanumanth Rao; Sankarasubramanian, G; Kumar, A Praveen

    2013-01-01

    This paper describes the existing feeds in use at the GMRT Observatory and details the ongoing development of next generation wideband feeds for the upgraded GMRT. The existing feeds include: feed with folded thick dipoles (for 150 MHz), dipole-disc feed (for 325 MHz), dual-band coaxial feed (for 233 MHZ and 610 MHz), and corrugated horn feed (for 1400–1450 MHz). The new broadband feeds covered in this paper are: cone-dipole feeds for 250–500 and 500–1000 MHz, wideband horn feed for 550–900 MHz, and dual ring feed for 130–260 MHz. Design techniques and performance results for these are described.

  6. Quasi-optical antenna-mixer-array design for terahertz frequencies

    Science.gov (United States)

    Guo, Yong; Potter, Kent A.; Rutledge, David B.

    1992-01-01

    A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed.

  7. Radar techniques using array antennas

    CERN Document Server

    Wirth, Wulf-Dieter

    2013-01-01

    Radar Techniques Using Array Antennas is a thorough introduction to the possibilities of radar technology based on electronic steerable and active array antennas. Topics covered include array signal processing, array calibration, adaptive digital beamforming, adaptive monopulse, superresolution, pulse compression, sequential detection, target detection with long pulse series, space-time adaptive processing (STAP), moving target detection using synthetic aperture radar (SAR), target imaging, energy management and system parameter relations. The discussed methods are confirmed by simulation stud

  8. Rapid Evaluation of Power Degradation in Series Connection of Single Feeding Microsized Microbial Fuel Cells

    KAUST Repository

    Rojas, Jhonathan Prieto; Alqarni, Wejdan Mohammed Mofleh; Hussain, Muhammad Mustafa

    2014-01-01

    We have developed a sustainable, single feeding, microsized, air-cathode and membrane-free microbial fuel cells with a volume of 40 mu L each, which we have used for rapid evaluation of power generation and viability of a series array of three cells seeking higher voltage levels. Contrary to expectations, the achieved power density was modest (45 mWm(-3)), limited due to non-uniformities in assembly and the single-channel feeding system.

  9. Rapid Evaluation of Power Degradation in Series Connection of Single Feeding Microsized Microbial Fuel Cells

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-07-08

    We have developed a sustainable, single feeding, microsized, air-cathode and membrane-free microbial fuel cells with a volume of 40 mu L each, which we have used for rapid evaluation of power generation and viability of a series array of three cells seeking higher voltage levels. Contrary to expectations, the achieved power density was modest (45 mWm(-3)), limited due to non-uniformities in assembly and the single-channel feeding system.

  10. Polarized coincidence electroproduction

    International Nuclear Information System (INIS)

    Heimann, R.L.

    1975-03-01

    A study is made of the inclusive electroproduction of single hadrons off a polarized target. Bjorken scaling laws and the hadron azimuthal distribution are derived from the quark parton model. The polarization asymmetries scale when the target spin is along the direction of the virtual photon, and (apart from significant exception) vanish for transverse spin. These results have a simple explanation; emphasis is given both to the general mathematical formalism and to intuitive physical reasoning. Through this framework other cases are considered: quarks with anomalous magnetic moment; renormalization group effects and asymptotic freedom; production of vector mesons (whose spin state is analysed by their decay); relation to large transverse momentum hadron production; and a covariant parton model calculation. Spin 0 partons and Regge singularities are also considered. All of these cases (apart from the last two) modify the pattern of conclusions. Vector meson production shows polarization enhancements in the density matrix element rhosub(0+); the renormalization group approach does not lead to any significant suppressions. They are also less severe in parton models for large Psub(T) hadrons, and are not supported by the covariantly formulated calculation. The origins of these differences are isolated and used to exemplify the sensitivity polarized hadron electroproduction has to delicate detail that is otherwise concealed. (author)

  11. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  12. Optical neutron polarizers

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1990-01-01

    A neutron wave will be refracted by an appropriately varying potential. Optical neutron polarizers use spatially varying, spin- dependent potentials to refract neutrons of opposite spin states into different directions, so that an unpolarized beam will be split into two beams of complementary polarization by such a device. This paper will concentrate on two methods of producing spin-dependent potentials which are particularly well-suited to polarizing cold neutron beams, namely thin-film structures and field-gradient techniques. Thin-film optical devices, such as supermirror multilayer structures, are usually designed to deviate only one spin-state, so that they offer the possibility of making insertion (transmission) polarizers. Very good supermirrors may now be designed and fabricated, but it is not always straightforward to design mirror-based devices which are useful in real (divergent beam) applications, and some practical configurations will be discussed. Field-gradient devices, which are usually based on multipolar magnets, have tended to be too expensive for general use, but this may change with new developments in superconductivity. Dipolar and hexapolar configurations will be considered, with emphasis on the focusing characteristics of the latter. 21 refs., 7 figs

  13. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  14. The polarized EMC effect

    Energy Technology Data Exchange (ETDEWEB)

    W. Bentz; I. C. Cloet; A. W. Thomas

    2007-02-01

    We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

  15. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    Ozarski, R.G.; Prior, J.

    1980-01-01

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  16. Spin-polarized photoemission

    International Nuclear Information System (INIS)

    Johnson, Peter D.

    1997-01-01

    Spin-polarized photoemission has developed into a versatile tool for the study of surface and thin film magnetism. In this review, we examine the methodology of the technique and its application to a number of different problems, including both valence band and core level studies. After a detailed review of spin-polarization measurement techniques and the related experimental requirements we consider in detail studies of the bulk properties both above and below the Curie temperature. This section also includes a discussion of observations relating to unique metastable phases obtained via epitaxial growth. The application of the technique to the study of surfaces, both clean and adsorbate covered, is reviewed. The report then examines, in detail, studies of the spin-polarized electronic structure of thin films and the related interfacial magnetism. Finally, observations of spin-polarized quantum well states in non-magnetic thin films are discussed with particular reference to their mediation of the oscillatory exchange coupling in related magnetic multilayers. (author)

  17. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  18. No More Polarization, Please!

    DEFF Research Database (Denmark)

    Hansen, Mia Reinholt

    and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on motivation, acknowledging the co-existence of intrinsic and extrinsic motivation, the possible interaction...

  19. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  20. Polarized Neutron Scattering

    OpenAIRE

    Roessli, B.; Böni, P.

    2000-01-01

    The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.

  1. DESY: HERA polarization

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-03-15

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization.

  2. Graphics of polar figure

    International Nuclear Information System (INIS)

    Macias B, L.R.

    1991-11-01

    The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

  3. Polarized light and optical measurement

    CERN Document Server

    Clarke, D N; Ter Haar, D

    2013-01-01

    Polarized Light and Optical Measurement is a five-chapter book that begins with a self-consistent conceptual picture of the phenomenon of polarization. Chapter 2 describes a number of interactions of light and matter used in devising optical elements in polarization studies. Specific optical elements are given in Chapter 3. The last two chapters explore the measurement of the state of polarization and the various roles played in optical instrumentation by polarization and polarization-sensitive elements. This book will provide useful information in this field of interest for research workers,

  4. The Big Optical Array

    International Nuclear Information System (INIS)

    Mozurkewich, D.; Johnston, K.J.; Simon, R.S.

    1990-01-01

    This paper describes the design and the capabilities of the Naval Research Laboratory Big Optical Array (BOA), an interferometric optical array for high-resolution imaging of stars, stellar systems, and other celestial objects. There are four important differences between the BOA design and the design of Mark III Optical Interferometer on Mount Wilson (California). These include a long passive delay line which will be used in BOA to do most of the delay compensation, so that the fast delay line will have a very short travel; the beam combination in BOA will be done in triplets, to allow measurement of closure phase; the same light will be used for both star and fringe tracking; and the fringe tracker will use several wavelength channels

  5. A 4 probe array

    Energy Technology Data Exchange (ETDEWEB)

    Fernando, C E [CEGB, Marchwood Engineering Laboratories, Marchwood, Southampton, Hampshire (United Kingdom)

    1980-11-01

    A NDT system is described which moves away from the present manual method using a single send/receive transducer combination and uses instead an array of four transducers. Four transducers are shown sufficient to define a point reflector with a resolution of m{lambda}z/R where m{lambda} is the minimum detectable path difference in the system (corresponding to a m cycle time resolution), z the range and R the radius of the array. Signal averaging with an input ADC rate of 100 MHz is used with voice output for the range data. Typical resolution measurements in a water tank are presented. We expect a resolution of the order of mm in steel at a range of 80 mm. The system is expected to have applications in automated, high resolution, sizing of defects and in the inspection of austenitic stainless steel welds. (author)

  6. Solar collector array

    Science.gov (United States)

    Hall, John Champlin; Martins, Guy Lawrence

    2015-09-06

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

  7. Phased array antenna control

    Science.gov (United States)

    Doland, G. D. (Inventor)

    1978-01-01

    Several new and useful improvements in steering and control of phased array antennas having a small number of elements, typically on the order of 5 to 17 elements are provided. Among the improvements are increasing the number of beam steering positions, reducing the possibility of phase transients in signals received or transmitted with the antennas, and increasing control and testing capacity with respect to the antennas.

  8. Seismometer array station processors

    International Nuclear Information System (INIS)

    Key, F.A.; Lea, T.G.; Douglas, A.

    1977-01-01

    A description is given of the design, construction and initial testing of two types of Seismometer Array Station Processor (SASP), one to work with data stored on magnetic tape in analogue form, the other with data in digital form. The purpose of a SASP is to detect the short period P waves recorded by a UK-type array of 20 seismometers and to edit these on to a a digital library tape or disc. The edited data are then processed to obtain a rough location for the source and to produce seismograms (after optimum processing) for analysis by a seismologist. SASPs are an important component in the scheme for monitoring underground explosions advocated by the UK in the Conference of the Committee on Disarmament. With digital input a SASP can operate at 30 times real time using a linear detection process and at 20 times real time using the log detector of Weichert. Although the log detector is slower, it has the advantage over the linear detector that signals with lower signal-to-noise ratio can be detected and spurious large amplitudes are less likely to produce a detection. It is recommended, therefore, that where possible array data should be recorded in digital form for input to a SASP and that the log detector of Weichert be used. Trial runs show that a SASP is capable of detecting signals down to signal-to-noise ratios of about two with very few false detections, and at mid-continental array sites it should be capable of detecting most, if not all, the signals with magnitude above msub(b) 4.5; the UK argues that, given a suitable network, it is realistic to hope that sources of this magnitude and above can be detected and identified by seismological means alone. (author)

  9. Lectin-Array Blotting.

    Science.gov (United States)

    Pazos, Raquel; Echevarria, Juan; Hernandez, Alvaro; Reichardt, Niels-Christian

    2017-09-01

    Aberrant protein glycosylation is a hallmark of cancer, infectious diseases, and autoimmune or neurodegenerative disorders. Unlocking the potential of glycans as disease markers will require rapid and unbiased glycoproteomics methods for glycan biomarker discovery. The present method is a facile and rapid protocol for qualitative analysis of protein glycosylation in complex biological mixtures. While traditional lectin arrays only provide an average signal for the glycans in the mixture, which is usually dominated by the most abundant proteins, our method provides individual lectin binding profiles for all proteins separated in the gel electrophoresis step. Proteins do not have to be excised from the gel for subsequent analysis via the lectin array but are transferred by contact diffusion from the gel to a glass slide presenting multiple copies of printed lectin arrays. Fluorescently marked glycoproteins are trapped by the printed lectins via specific carbohydrate-lectin interactions and after a washing step their binding profile with up to 20 lectin probes is analyzed with a fluorescent scanner. The method produces the equivalent of 20 lectin blots in a single experiment, giving detailed insight into the binding epitopes present in the fractionated proteins. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  10. Array processor architecture

    Science.gov (United States)

    Barnes, George H. (Inventor); Lundstrom, Stephen F. (Inventor); Shafer, Philip E. (Inventor)

    1983-01-01

    A high speed parallel array data processing architecture fashioned under a computational envelope approach includes a data base memory for secondary storage of programs and data, and a plurality of memory modules interconnected to a plurality of processing modules by a connection network of the Omega gender. Programs and data are fed from the data base memory to the plurality of memory modules and from hence the programs are fed through the connection network to the array of processors (one copy of each program for each processor). Execution of the programs occur with the processors operating normally quite independently of each other in a multiprocessing fashion. For data dependent operations and other suitable operations, all processors are instructed to finish one given task or program branch before all are instructed to proceed in parallel processing fashion on the next instruction. Even when functioning in the parallel processing mode however, the processors are not locked-step but execute their own copy of the program individually unless or until another overall processor array synchronization instruction is issued.

  11. A Novel T-Fed 4-Element Quasi-Lumped Resonator Antenna Array

    Directory of Open Access Journals (Sweden)

    S.S. Olokede

    2014-06-01

    Full Text Available In this paper, electrically small corporately T-fed quasi-lumped element resonator antenna array is investigated. The radiating element, a quasi-lumped element resonator is excited by a novel semi hybrid ring-like T-shaped corporate feed network. The characteristics losses due to Ohmic and discontinuities along the feed line which invariably constitutes complex feed structures are mitigated at the instance of the proposed antenna. Technique to implement the compact array with the intent to enhance the gain is presented. The operation dynamics of the feed along with its theoretical explanation is also reported. Findings indicates that the measured gain is 10.97 dBi for antenna of an estate area of about 0.677λ_0 × 1.257λ_0 sq. mm. Valuable insight to the optimum design in terms of compactness, good gain, and ease of fabrication is documented.

  12. Polarized nuclear target based on parahydrogen induced polarization

    OpenAIRE

    Budker, D.; Ledbetter, M. P.; Appelt, S.; Bouchard, L. S.; Wojtsekhowski, B.

    2012-01-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.

  13. Corporate array of micromachined dipoles on silicon wafer for 60 GHz communication systems

    KAUST Repository

    Sallam, M. O.

    2013-03-01

    In this paper, an antenna array operating at 60 GHz and realized on 0.675 mm thick silicon substrate is presented. The array is constructed using four micromachined half-wavelength dipoles fed by a corporate feeding network. Isolation between the antenna array and its feeding network is achieved via a ground plane. This arrangement leads to maximizing the broadside radiation with relatively high front-to-back ratio. Simulations have been carried out using both HFSS and CST, which showed very good agreement. Results reveal that the proposed antenna array has good radiation characteristics, where the directivity, gain, and radiation efficiency are around 10.5 dBi, 9.5 dBi, and 79%, respectively. © 2013 IEEE.

  14. Scattering cross section of unequal length dipole arrays

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents a detailed and systematic analytical treatment of scattering by an arbitrary dipole array configuration with unequal-length dipoles, different inter-element spacing and load impedance. It provides a physical interpretation of the scattering phenomena within the phased array system. The antenna radar cross section (RCS) depends on the field scattered by the antenna towards the receiver. It has two components, viz. structural RCS and antenna mode RCS. The latter component dominates the former, especially if the antenna is mounted on a low observable platform. The reduction in the scattering due to the presence of antennas on the surface is one of the concerns towards stealth technology. In order to achieve this objective, a detailed and accurate analysis of antenna mode scattering is required. In practical phased array, one cannot ignore the finite dimensions of antenna elements, coupling effect and the role of feed network while estimating the antenna RCS. This book presents the RCS estimati...

  15. Advanced Liquid Feed Experiment

    Science.gov (United States)

    Distefano, E.; Noll, C.

    1993-06-01

    The Advanced Liquid Feed Experiment (ALFE) is a Hitchhiker experiment flown on board the Shuttle of STS-39 as part of the Space Test Payload-1 (STP-1). The purpose of ALFE is to evaluate new propellant management components and operations under the low gravity flight environment of the Space Shuttle for eventual use in an advanced spacecraft feed system. These components and operations include an electronic pressure regulator, an ultrasonic flowmeter, an ultrasonic point sensor gage, and on-orbit refill of an auxiliary propellant tank. The tests are performed with two transparent tanks with dyed Freon 113, observed by a camera and controlled by ground commands and an on-board computer. Results show that the electronic pressure regulator provides smooth pressure ramp-up, sustained pressure control, and the flexibility to change pressure settings in flight. The ultrasonic flowmeter accurately measures flow and detects gas ingestion. The ultrasonic point sensors function well in space, but not as a gage during sustained low-gravity conditions, as they, like other point gages, are subject to the uncertainties of propellant geometry in a given tank. Propellant transfer operations can be performed with liquid-free ullage equalization at a 20 percent fill level, gas-free liquid transfer from 20-65 percent fill level, minimal slosh, and can be automated.

  16. [Puppy feeding in Switzerland].

    Science.gov (United States)

    Liesegang, A; Füglistaller, C; Wichert, B

    2009-11-01

    In this study breeders and owners of 8 different dog breeds (Beagle, Bernese Mountain Dog, Cavalier King Charles Spaniel, Great Dane, German Shepherd (GS), Labrador, Papillon, Sheltie) were interviewed to obtain information on puppy feeding in Switzerland. Besides answering a questionnaire (husbandry and feeding of the puppies), the participation in this study included weekly weighing of the animals as well as exact documentation of the amount fed to the animals. Totally 67 dog breeders and 131 new owners of puppies participated. The weight development of the puppies was mostly parallel to the growth curve in the GS, Labradors and Shelties. There were some substantial differences to the ideal growth curve within the other breeds. The daily mean energy requirement was estimated too high, when including the growth curves. 80 - 90 % of the recommendations would be sufficient for most animals. The calcium supply was in the range of tolerance in all breeds. Nearly all breeders used commercially available complete food while raising the puppies. No breed-specific differences could be shown.

  17. One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers

    Science.gov (United States)

    Lin, Yo-Sheng; Hu, Chun-Hao; Chang, Chi-Ho; Tsao, Ping-Chang

    2018-06-01

    In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers.

  18. Radiation Resistance and Gain of Homogeneous Ring Quasi-Array

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1954-01-01

    In a previous paper homogeneous ring quasi-arrays of tangential or radial dipoles were introduced, i.e. systems of dipoles arranged equidistantly along a circle, the dipoles being oriented in tangential or radial directions and carrying currents with the same amplitude, but with a phase that incr......In a previous paper homogeneous ring quasi-arrays of tangential or radial dipoles were introduced, i.e. systems of dipoles arranged equidistantly along a circle, the dipoles being oriented in tangential or radial directions and carrying currents with the same amplitude, but with a phase...... that increases uniformly along the circle. Such quasi-arrays are azimuthally omnidirectional, and the radiated field will be mainly horizontally polarized and concentrated around the plane of the circle. In this paper expressions are obtained for the radiation resistance and the gain of homogeneous ring quasi...

  19. Realizing Broadband and Invertible Linear-to-circular Polarization Converter with Ultrathin Single-layer Metasurface

    Science.gov (United States)

    Li, Zhancheng; Liu, Wenwei; Cheng, Hua; Chen, Shuqi; Tian, Jianguo

    2015-01-01

    The arbitrary control of the polarization states of light has attracted the interest of the scientific community because of the wide range of modern optical applications that such control can afford. However, conventional polarization control setups are bulky and very often operate only within a narrow wavelength range, thereby resisting optical system miniaturization and integration. Here, we present the basic theory, simulated demonstration, and in-depth analysis of a high-performance broadband and invertible linear-to-circular (LTC) polarization converter composed of a single-layer gold nanorod array with a total thickness of ~λ/70 for the near-infrared regime. This setup can transform a circularly polarized wave into a linearly polarized one or a linearly polarized wave with a wavelength-dependent electric field polarization angle into a circularly polarized one in the transmission mode. The broadband and invertible LTC polarization conversion can be attributed to the tailoring of the light interference at the subwavelength scale via the induction of the anisotropic optical resonance mode. This ultrathin single-layer metasurface relaxes the high-precision requirements of the structure parameters in general metasurfaces while retaining the polarization conversion performance. Our findings open up intriguing possibilities towards the realization of novel integrated metasurface-based photonics devices for polarization manipulation, modulation, and phase retardation. PMID:26667360

  20. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  1. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

  2. THE METHODS OF PRODUCING AND ANALYZING POLARIZED NEUTRON BEAMS FOR HYSPEC AT THE SNS

    International Nuclear Information System (INIS)

    SHAPIRO, S.M.; PASSELL, L.; ZALIZNYAK, A.; GHOSH, V.J.; LEONHARDT, W.L.; HAGEN, M.E.

    2005-01-01

    The Hybrid Spectrometer (HYSPEC), under construction at the SNS on beam line 14B, is the only inelastic scattering instrument designed to enable polarization of the incident and the scattered neutron beams. A Heusler monochromator will replace the graphite crystal for producing polarized neutrons. In the scattered beam it is planned to use a collimator--multi-channel supermirror bender array to analyze the polarization of the scattered beam over the final energy range from 5-20 meV. Other methods of polarization analysis under consideration such as transmission filters using He 3 , Sm, and polarized protons are considered. Their performance is estimated and a comparison of the various methods of polarization is made

  3. Vector-Sensor MUSIC for Polarized Seismic Sources Localization

    Directory of Open Access Journals (Sweden)

    Jérôme I. Mars

    2005-01-01

    Full Text Available This paper addresses the problem of high-resolution polarized source detection and introduces a new eigenstructure-based algorithm that yields direction of arrival (DOA and polarization estimates using a vector-sensor (or multicomponent-sensor array. This method is based on separation of the observation space into signal and noise subspaces using fourth-order tensor decomposition. In geophysics, in particular for reservoir acquisition and monitoring, a set of Nx-multicomponent sensors is laid on the ground with constant distance Δx between them. Such a data acquisition scheme has intrinsically three modes: time, distance, and components. The proposed method needs multilinear algebra in order to preserve data structure and avoid reorganization. The data is thus stored in tridimensional arrays rather than matrices. Higher-order eigenvalue decomposition (HOEVD for fourth-order tensors is considered to achieve subspaces estimation and to compute the eigenelements. We propose a tensorial version of the MUSIC algorithm for a vector-sensor array allowing a joint estimation of DOA and signal polarization estimation. Performances of the proposed algorithm are evaluated.

  4. Source of spin polarized electrons

    International Nuclear Information System (INIS)

    Pierce, D.T.; Meier, F.A.; Siegmann, H.C.

    1976-01-01

    A method is described of producing intense beams of polarized free electrons in which a semiconductor with a spin orbit split valence band and negative electron affinity is used as a photocathode and irradiated with circularly polarized light

  5. Linearly polarized photons at ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Eberhardt, Holger [Physikalisches Institut, Universitaet Bonn (Germany)

    2009-07-01

    To investigate the nucleon resonance regime in meson photoproduction, double polarization experiments are currently performed at the electron accelerator ELSA in Bonn. The experiments make use of a polarized target and circularly or linearly polarized photon beams. Linearly polarized photons are produced by coherent bremsstrahlung from an accurately aligned diamond crystal. The orientation of the crystal with respect to the electron beam is measured using the Stonehenge-Technique. Both, the energy of maximum polarization and the plane of polarization, can be deliberately chosen for the experiment. The linearly polarized beam provides the basis for the measurement of azimuthal beam asymmetries, such as {sigma} (unpolarized target) and G (polarized target). These observables are extracted in various single and multiple meson photoproduction channels.

  6. 2D Traveling Wave Array Employing a Trapezoidal Dielectric Wedge for Beam Steering

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranada, Felix A.

    2014-01-01

    This presentation addresses the progress made so far in the development of an antenna array with reconfigurable transmission line feeds connecting each element in series. In particular, 2D traveling wave array employing trapezoidal Dielectric Wedge for Beam Steering will be discussed. The presentation includes current status of the effort and suggested future work. The work is being done as part of the NASA Office of the Chief Technologist's Space Technology Research Fellowship (NSTRF).

  7. North Polar Cap

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour. In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime. The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap. Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen

  8. Nanophotonic production, modulation and switching of ions by silicon microcolumn arrays

    Science.gov (United States)

    Vertes, Akos; Walker, Bennett N.

    2013-09-10

    The production and use of silicon microcolumn arrays that harvest light from a laser pulse to produce ions are described. The systems of the present invention seem to behave like a quasi-periodic antenna array with ion yields that show profound dependence on the plane of laser light polarization and the angle of incidence. By providing photonic ion sources, this enables enhanced control of ion production on a micro/nano scale and direct integration with miniaturized analytical devices.

  9. Stanford polarized atomic beam target

    International Nuclear Information System (INIS)

    Mavis, D.G.; Dunham, J.S.; Hugg, J.W.; Glavish, H.F.

    1976-01-01

    A polarized atomic beam source was used to produce an atomic hydrogen beam which was in turn used as a polarized proton target. A target density of 2 x 10'' atoms/cm 3 and a target polarization of 0.37 without the use of rf transitions were measured. These measurements indicate that a number of experiments are currently feasible with a variety of polarized target beams

  10. Three-photon polarization ququarts: polarization, entanglement and Schmidt decompositions

    International Nuclear Information System (INIS)

    Fedorov, M V; Miklin, N I

    2015-01-01

    We consider polarization states of three photons, propagating collinearly and having equal given frequencies but with arbitrary distributed horizontal or vertical polarizations of photons. A general form of such states is a superposition of four basic three-photon polarization modes, to be referred to as the three-photon polarization ququarts (TPPQ). All such states can be considered as consisting of one- and two-photon parts, which can be entangled with each other. The degrees of entanglement and polarization, as well as the Schmidt decomposition and Stokes vectors of TPPQ are found and discussed. (paper)

  11. Factors affecting the performance of large-aperture microphone arrays

    Science.gov (United States)

    Silverman, Harvey F.; Patterson, William R.; Sachar, Joshua

    2002-05-01

    Large arrays of microphones have been proposed and studied as a possible means of acquiring data in offices, conference rooms, and auditoria without requiring close-talking microphones. When such an array essentially surrounds all possible sources, it is said to have a large aperture. Large-aperture arrays have attractive properties of spatial resolution and signal-to-noise enhancement. This paper presents a careful comparison of theoretical and measured performance for an array of 256 microphones using simple delay-and-sum beamforming. This is the largest currently functional, all digital-signal-processing array that we know of. The array is wall-mounted in the moderately adverse environment of a general-purpose laboratory (8 m×8 m×3 m). The room has a T60 reverberation time of 550 ms. Reverberation effects in this room severely impact the array's performance. However, the width of the main lobe remains comparable to that of a simplified prediction. Broadband spatial resolution shows a single central peak with 10 dB gain about 0.4 m in diameter at the -3 dB level. Away from that peak, the response is approximately flat over most of the room. Optimal weighting for signal-to-noise enhancement degrades the spatial resolution minimally. Experimentally, we verify that signal-to-noise gain is less than proportional to the square root of the number of microphones probably due to the partial correlation of the noise between channels, to variation of signal intensity with polar angle about the source, and to imperfect correlation of the signal over the array caused by reverberations. We show measurements of the relative importance of each effect in our environment.

  12. Polarization Properties of 24 Fermi-Detected Blazars

    Science.gov (United States)

    Linford, Justin; Taylor, G. B.; Schinzel, F. K.; Zavala, R. T.

    2013-01-01

    Gamma-ray emitting blazars have been shown to frequently have significant polarization at radio wavelengths. In early 2012, we obtained Very Long Baseline Array (VLBA) observations of 24 blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. These observations utilized the new 2 gigabit-per-second mode of the VLBA. We observed each source with full polarization at 8.4 GHz, 15 GHz, and 22 GHz with 256 MHz of total bandwidth per polarization. Our sample contains 14 flat-spectrum radio quasars (FSRQs) and 10 BL Lacertae objects (BL Lacs). We analyze the spectral index, rotation measure, and magnetic field structures of these 24 gamma-ray loud blazars.

  13. IRIS Arrays: Observing Wavefields at Multiple Scales and Frequencies

    Science.gov (United States)

    Sumy, D. F.; Woodward, R.; Frassetto, A.

    2014-12-01

    The Incorporated Research Institutions for Seismology (IRIS) provides instruments for creating and operating seismic arrays at a wide range of scales. As an example, for over thirty years the IRIS PASSCAL program has provided instruments to individual Principal Investigators to deploy arrays of all shapes and sizes on every continent. These arrays have ranged from just a few sensors to hundreds or even thousands of sensors, covering areas with dimensions of meters to thousands of kilometers. IRIS also operates arrays directly, such as the USArray Transportable Array (TA) as part of the EarthScope program. Since 2004, the TA has rolled across North America, at any given time spanning a swath of approximately 800 km by 2,500 km, and thus far sampling 2% of the Earth's surface. This achievement includes all of the lower-48 U.S., southernmost Canada, and now parts of Alaska. IRIS has also facilitated specialized arrays in polar environments and on the seafloor. In all cases, the data from these arrays are freely available to the scientific community. As the community of scientists who use IRIS facilities and data look to the future they have identified a clear need for new array capabilities. In particular, as part of its Wavefields Initiative, IRIS is exploring new technologies that can enable large, dense array deployments to record unaliased wavefields at a wide range of frequencies. Large-scale arrays might utilize multiple sensor technologies to best achieve observing objectives and optimize equipment and logistical costs. Improvements in packaging and power systems can provide equipment with reduced size, weight, and power that will reduce logistical constraints for large experiments, and can make a critical difference for deployments in harsh environments or other situations where rapid deployment is required. We will review the range of existing IRIS array capabilities with an overview of previous and current deployments and examples of data and results. We

  14. Polarization effects in hadron fragmentation

    International Nuclear Information System (INIS)

    Lednicky, R.

    1984-01-01

    Hadron polarization (spin alignment) and polarization asymmetry are discussed in terms of the quark recombination model with the spin-orbit interaction taken into account. It is shown that predictions of this model are at least in qualitative agreement with experimental data. Various polarization mechanisms in terms of this model and the possibility of their checking are also discussed

  15. Automatic liquid nitrogen feeding device

    International Nuclear Information System (INIS)

    Gillardeau, J.; Bona, F.; Dejachy, G.

    1963-01-01

    An automatic liquid nitrogen feeding device has been developed (and used) in the framework of corrosion tests realized with constantly renewed uranium hexafluoride. The issue was to feed liquid nitrogen to a large capacity metallic trap in order to condensate uranium hexafluoride at the exit of the corrosion chambers. After having studied various available devices, a feeding device has been specifically designed to be robust, secure and autonomous, as well as ensuring a high liquid nitrogen flowrate and a highly elevated feeding frequency. The device, made of standard material, has been used during 4000 hours without any problem [fr

  16. Detection of polar vapours

    International Nuclear Information System (INIS)

    Blyth, D.A.

    1980-01-01

    Apparatus for monitoring for polar vapours in a gas consists of (i) a body member defining a passage through which a continuous stream of the gas passes; (ii) an ionising source associated with a region of the passage such that ionization of the gas stream takes place substantially only within the region and also any polar vapour molecules present therein will react with the gas formed to generate ion clusters; and (iii) an electrode for collecting ions carried by the gas stream, the electrode being positioned in the passage downstream of the region and separated from the region by a sufficient distance to ensure that no substantial number of the gas ions formed in said region remains in the gas stream at the collector electrode whilst ensuring that a substantial proportion of the ion clusters formed in the region does remain in the gas stream at the collector electrode. (author)

  17. Perspectives for polarized antiprotons

    International Nuclear Information System (INIS)

    Lenisa, Paolo

    2012-01-01

    Polarized antiprotons would open a new window in hadron physics providing access to a wealth of single and double spin observables in proton-antiproton interactions. The PAX Collaboration aims to perform the first ever measurement of the spin-dependence of the proton-antiproton cross section at the AD ring at CERN. The spin-dependence of the cross section could in principle be exploited by the spin-filtering technique for the production of a polarized antiproton beam. As a preparatory phase to the experimentation at AD, the PAX Collaboration has initiated a series of dedicated studies with protons at the COSY-ring in Juelich (Germany), aimed at the commissioning of the experimental apparatus and confirmation of the predictions for spin-filtering with protons.

  18. The Polar Cusp

    International Nuclear Information System (INIS)

    Holtet, J.A.; Egeland, A.

    1985-01-01

    The upper atmosphere at high latitudes is often called the ''earth's window to outer space.'' Through various electrodynamic coupling processes, as well as direct transfer of particles, many of the geophysical effects displayed are direct manifestations of phenomena occurring in deep space. The high latitude ionosphere also exerts a feedback on the regions of the magnetosphere and atmosphere to which it is coupled. Of particular interest are the sections of the near space known as the Polar Cusp. A vast portion of the Earth's magnetic field envelope is electrically connected to these regions. This geometry results in a spatial mapping of the magnetospheric processes and a focusing on the ionosphere. In the Polar Cusps, the solar wind plasma also has direct access to the upper atmosphere

  19. Polarized electrogowdy spacetimes censored

    International Nuclear Information System (INIS)

    Nungesser, Ernesto

    2010-01-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  20. Polarized electrogowdy spacetimes censored

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto, E-mail: ernesto.nungesser@aei.mpg.d [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2010-05-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  1. Feeding premature neonate

    DEFF Research Database (Denmark)

    Dam, Mie S.; Juhl, Sandra M.; Sangild, Per T.

    2017-01-01

    Kinship, understood as biogenetic proximity, between a chosen animal model and a human patient counterpart, is considered essential to the process of ‘translating’ research from the experimental animal laboratory to the human clinic. In the Danish research centre, NEOMUNE, premature piglets are fed...... a novel milk diet (bovine colostrum) to model the effects of this new diet in premature infants. Our ethnographic fieldwork in an experimental pig laboratory and a neonatal intensive care unit (NICU) in 2013–2014 shows that regardless of biogenetics, daily practices of feeding, housing, and clinical care...... the researchers refer to as the ‘translatability’ of the results. In the NICU, parents of premature infants likewise imagine a kind of interspecies kinship when presented with the option to supplement mother's own milk with bovine colostrum for the first weeks after birth. However, in this setting the NICU...

  2. Polarization of lanthanum nucleus by dynamic polarization method

    International Nuclear Information System (INIS)

    Adachi, Toshikazu; Ishimoto, Shigeru; Masuda, Yasuhiro; Morimoto, Kimio

    1989-01-01

    Preliminary studies have been carried out concerning the application of a dynamic polarization method to polarizing lanthanum fluoride single crystal to be employed as target in experiments with time reversal invariance. The present report briefly outlines the dynamic polarization method and describes some preliminary studies carried out so far. Dynamic polarization is of particular importance because no techniques are currently available that can produce highly polarized static nucleus. Spin interaction between electrons and protons (nuclei) plays a major role in the dynamic polarization method. In a thermal equilibrium state, electrons are polarized almost completely while most protons are not polarized. Positively polarized proton spin is produced by applying microwave to this system. The most hopeful candidate target material is single crystal of LaF 3 containing neodymium because the crystal is chemically stable and easy to handle. The spin direction is of great importance in experiments with time reversal invariance. The spin of neutrons in the target can be cancelled by adjusting the external magnetic field applied to a frozen polarized target. In a frozen spin state, the polarity decreases slowly with a relaxation time that depends on the external magnetic field and temperature. (N.K.)

  3. Breast feeding in Kelantan.

    Science.gov (United States)

    Balakrishnan, S; Hussein, H B

    1977-04-01

    The incidence of breastfeeding is investigated in relation to duration of breastfeeding without supplementation and the age when solids were first introduced in the infant's diet. The study also evaluates the awareness of the mothers of the benefits of breast milk. 461 mothers were interviewed in May 1976 by 3 doctors including the author. 95% (438) were found to breastfeed their babies at least once or twice a day. However, only 18% (86) of the mothers were fully breastfeeding up to 3 months and 9% (45) were breastfeeding without added solids up to 6 months. A disappointing finding was the introduction of solid foods by 78% (351) of the mothers before the end of the 3rd month; of these, 117 or 25% have introduced the solids as early as the 1st 6 months. Only 5% (23) were artificially feeding their infants. 86% (399) agreed that breast milk was the best milk for their children but only 277 (59%) agreed that infection occurs less frequently in breastfed than bottlefed children. 65% (302) were aware that solids should be introduced after 6 months to the infant's diet. Only 48% (222) were aware that a well-balanced diet is essential for an adequate supply of breast milk. Although 50% (232) reported that they were advised by nurses or bidans to breastfeed their children, only 37% (172) were given instructions on the technique of breastfeeding. Breastfeeding programs launched by the Ministry of Health should promote breastfeeding for at least 4-6 months duration and discourage early complement feeding and introduction of solids to infants less than 6 months of age.

  4. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  5. Polarized advanced fuel reactors

    International Nuclear Information System (INIS)

    Kulsrud, R.M.

    1987-07-01

    The d- 3 He reaction has the same spin dependence as the d-t reaction. It produces no neutrons, so that if the d-d reactivity could be reduced, it would lead to a neutron-lean reactor. The current understanding of the possible suppression of the d-d reactivity by spin polarization is discussed. The question as to whether a suppression is possible is still unresolved. Other advanced fuel reactions are briefly discussed. 11 refs

  6. Polish polar research (outline

    Directory of Open Access Journals (Sweden)

    Krzysztof Ludwik Birkenmajer

    2017-12-01

    Full Text Available The article describes Polish research and discoveries in the Arctic and the Antarctic since the 19th century. The author is a geologist and since 1956 has been engaged in scientific field research on Spitsbergen, Greenland and Antarctica (23 expeditions. For many years chairman of the Committee on Polar Research of the Polish Academy of Sciences, he is now its Honorary Chairman.

  7. South Polar Polygons

    Science.gov (United States)

    2005-01-01

    4 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a polgyon-cracked surface, into which deep, somewhat kidney-bean-shaped pits have formed. These are landscapes of the martian south polar residual cap. This view was captured during May 2005. Location near: 86.9oS, 5.1oW Image width: 1.5 km (0.9 mi) Illumination from: upper left Season Southern Spring

  8. Novel polar sedimentary porphyrins

    Science.gov (United States)

    Prowse, W. G.; Maxwell, J. R.

    1989-11-01

    Two polar nickel porphyrins in Messel oil shale are shown to be the C 32 and C 30 components IIIa,b. In the sample examined, component IIIa is by far the major porphyrin alcohol and is present in an abundance similar to that of the major nickel alkyl porphyrin. These primary alcohols, which do not appear to be artifacts, are structurally related to alkyl porphyrins reported previously in Serpiano oil shale.

  9. Polarization properties of linearly polarized parabolic scaling Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

    2016-10-07

    The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

  10. Effect of feeding frequency and feeding rate on growth performance ...

    African Journals Online (AJOL)

    Fish fed at higher feeding rates accumulated significantly more lipid within the body and had associated decreases in moisture, protein, and ash content, but carcass composition was unaffected by feeding frequency. Juvenile pompano show better growth performance when fed 10% BW/day 3 and 6 times a day.

  11. Feed intake, growth and feed utilization patterns of pigs highly ...

    African Journals Online (AJOL)

    Mean daily live mass gain was, however, 174 g/day (20,5%) more for the Large White boars and feed conversion16,5% ... of protein and fat in genetically lean and obese pigs, and showed that feed ..... regulation of growth and production.

  12. Applications of polarized neutrons

    International Nuclear Information System (INIS)

    Mezei, F.

    1993-01-01

    The additional spin degree of freedom of the neutron can be made use of in neutron scattering work in two fundamental ways: (a) directly for the identification of magnetic scattering effects and (b) indirectly as a spectroscopic tool for modulating and analysing beams. Although strong magnetic scattering contributions can often be studied by unpolarized neutrons, a fully unambiguous separation of nuclear and magnetic phenomena can only be achieved by the additional information provided by polarized neutrons, especially if one of the two kinds of contributions is weak compared to the other. In the most general case a sample with both magnetic and nuclear features can be characterized by as many as 16 independent dynamic correlation functions instead of the single well known S(q, ω) for non-magnetic nuclear scattering only. Polarization analysis in principle allows one to determine all these 16 functions. The indirect applications of polarized neutrons are also steadily gaining importance. The most widely used method of this kind, the application of Larmor precessions for high resolution energy analysis in Neutron Spin Echo spectroscopy opened up a whole new domain in inelastic neutron scattering which was not accessible to any other spectroscopic method with or without neutrons before. (author)

  13. Pliocene geomagnetic polarity epochs

    Science.gov (United States)

    Dalrymple, G.B.; Cox, A.; Doell, Richard R.; Gromme, C.S.

    1967-01-01

    A paleomagnetic and K-Ar dating study of 44 upper Miocene and Pliocene volcanic units from the western United States suggests that the frequency of reversals of the earth's magnetic field during Pliocene time may have been comparable with that of the last 3.6 m.y. Although the data are too limited to permit the formal naming of any new polarity epochs or events, four polarity transitions have been identified: the W10 R/N boundary at 3.7 ?? 0.1 m.y., the A12 N/R boundary at 4.9 ?? 0.1 m.y., the W32 N/R boundary at 9.0 ?? 0.2m.y., and the W36 R/N boundary at 10.8 ?? 0.3 - 1.0 m.y. The loss of absolute resolution of K-Ar dating in older rocks indicates that the use of well defined stratigraphic successions to identify and date polarity transitions will be important in the study of Pliocene and older reversals. ?? 1967.

  14. Educational Cosmic Ray Arrays

    International Nuclear Information System (INIS)

    Soluk, R. A.

    2006-01-01

    In the last decade a great deal of interest has arisen in using sparse arrays of cosmic ray detectors located at schools as a means of doing both outreach and physics research. This approach has the unique advantage of involving grade school students in an actual ongoing experiment, rather then a simple teaching exercise, while at the same time providing researchers with the basic infrastructure for installation of cosmic ray detectors. A survey is made of projects in North America and Europe and in particular the ALTA experiment at the University of Alberta which was the first experiment operating under this paradigm

  15. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water-reflected (i.e. surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established

  16. AUTOMATION OF IN FEED CENTERLESS GRINDING MACHINE

    OpenAIRE

    Piyusha P. Jadhav*, Sachin V. Lomte, Sudhir Surve

    2017-01-01

    In-feed centerless grinding technique offers a major contribution to the industries. This is the alternative in-feed centerless grinding technique using regulating wheel. Mainly centerless grinding is divided in three types, and those are End feed, in-feed and through feed Centerless grinding. This paper mainly deals with low cost automation on in-feed Centerless grinding machine using regulating wheel suitable for multiple in-feed type jobs. It deals with the development of a Centerless grin...

  17. Particle sorting by Paramecium cilia arrays.

    Science.gov (United States)

    Mayne, Richard; Whiting, James G H; Wheway, Gabrielle; Melhuish, Chris; Adamatzky, Andrew

    Motile cilia are cell-surface organelles whose purposes, in ciliated protists and certain ciliated metazoan epithelia, include generating fluid flow, sensing and substance uptake. Certain properties of cilia arrays, such as beating synchronisation and manipulation of external proximate particulate matter, are considered emergent, but remain incompletely characterised despite these phenomena having being the subject of extensive modelling. This study constitutes a laboratory experimental characterisation of one of the emergent properties of motile cilia: manipulation of adjacent particulates. The work demonstrates through automated videomicrographic particle tracking that interactions between microparticles and somatic cilia arrays of the ciliated model organism Paramecium caudatum constitute a form of rudimentary 'sorting'. Small particles are drawn into the organism's proximity by cilia-induced fluid currents at all times, whereas larger particles may be held immobile at a distance from the cell margin when the cell generates characteristic feeding currents in the surrounding media. These findings can contribute to the design and fabrication of biomimetic cilia, with potential applications to the study of ciliopathies. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Review of polarized ammonium target

    International Nuclear Information System (INIS)

    Matsuda, Tatsuo

    1987-01-01

    Recently, ammonia (NH 3 ) and deutron ammonia (ND 3 ), instead of conventional alcohol substances, have been used more frequently as a polarized target substance for experiments of polarization at high energy regions. This article reviews major features of the polarized (deutron) ammonia targets. The dynamic nuclear polarization (DNT) method is widely used in high energy polarization experiments. While only a low polarization degree of hydrogen nucleus of 1.7 percent can be obtained by the Brute force method, DNP can produce polarization as high as ∼ 90 percent (2.5 T, ∼ 200 mK). In 1979, ammonia was irradiated with radiations to form NH 2 free radicals, resulting in the achievement of a high polarization degree of greater than 90 percent (hydrogen). Since then, ammonia and deutron ammonia have increasingly been replacing alcohols including butanol. Irradiation of a target substance with radiations destroys the structure of the substance, leading to a decrease in polarization degree. However, ammonia produces unpaired electrons as a result of irradiation, allowing it to be highly resistant to radiation. This report also present some study results, including observations on effects of radiation on the polarization degree of a target, effects of annealing, and polarization of 14 N. A process for producing an ammonia target is also described. (Nogami, K.)

  19. Polarization: A must for fusion

    Directory of Open Access Journals (Sweden)

    Didelez J.-P.

    2013-11-01

    Full Text Available The complete polarization of DT fuel would increase the fusion reactivity by 50% in magnetic as well as in inertial confinements. The persistence of polarization in a fusion process could be tested, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the emitted neutrons and the change in the corresponding total Cross Section (CS can sign the polarization persistence. The polarization of solid H2, D2 or T2 Hydrogen isotopes is very difficult. However, it has been possible to polarize HD, a hetero-molecular form of Hydrogen, by static polarization, at very low temperature and very high field. The radioactivity of DT molecules forbids there high polarization by the static method, therefore one has to develop the Dynamic Nuclear Polarization (DNP by RF transitions. The DNP of HD has been investigated in the past. The magnetic properties of HD and DT molecules are very similar, it is therefore expected that any polarization result obtained with HD could be extrapolated to DT.

  20. Selecting Sums in Arrays

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Jørgensen, Allan Grønlund

    2008-01-01

    In an array of n numbers each of the \\binomn2+nUnknown control sequence '\\binom' contiguous subarrays define a sum. In this paper we focus on algorithms for selecting and reporting maximal sums from an array of numbers. First, we consider the problem of reporting k subarrays inducing the k largest...... sums among all subarrays of length at least l and at most u. For this problem we design an optimal O(n + k) time algorithm. Secondly, we consider the problem of selecting a subarray storing the k’th largest sum. For this problem we prove a time bound of Θ(n · max {1,log(k/n)}) by describing...... an algorithm with this running time and by proving a matching lower bound. Finally, we combine the ideas and obtain an O(n· max {1,log(k/n)}) time algorithm that selects a subarray storing the k’th largest sum among all subarrays of length at least l and at most u....

  1. Programmable cellular arrays. Faults testing and correcting in cellular arrays

    International Nuclear Information System (INIS)

    Cercel, L.

    1978-03-01

    A review of some recent researches about programmable cellular arrays in computing and digital processing of information systems is presented, and includes both combinational and sequential arrays, with full arbitrary behaviour, or which can realize better implementations of specialized blocks as: arithmetic units, counters, comparators, control systems, memory blocks, etc. Also, the paper presents applications of cellular arrays in microprogramming, in implementing of a specialized computer for matrix operations, in modeling of universal computing systems. The last section deals with problems of fault testing and correcting in cellular arrays. (author)

  2. Elite Polarization and Public Opinion

    DEFF Research Database (Denmark)

    Robison, Joshua; Mullinix, Kevin

    2016-01-01

    Elite polarization has reshaped American politics and is an increasingly salient aspect of news coverage within the United States. As a consequence, a burgeoning body of research attempts to unravel the effects of elite polarization on the mass public. However, we know very little about how...... polarization is communicated to the public by news media. We report the results of one of the first content analyses to delve into the nature of news coverage of elite polarization. We show that such coverage is predominantly critical of polarization. Moreover, we show that unlike coverage of politics focused...... on individual politicians, coverage of elite polarization principally frames partisan divisions as rooted in the values of the parties rather than strategic concerns. We build on these novel findings with two survey experiments exploring the influence of these features of polarization news coverage on public...

  3. The polarization of fast neutrons

    International Nuclear Information System (INIS)

    Talov, V.V.

    2001-01-01

    It is insufficient to know coordinates and momentum to describe a state of a neutron. It is necessary to define a spin orientation. As far as it is known from quantum mechanics, a half spin has a projection in the positive direction or in the negative direction. The probability of both projections in an unpolarized beam is equal. If a direction exists, in which the projection is more probably then beam is called polarized in this direction. It is essential to know polarization of neutrons for characteristics of a neutron source, which is emitting it. The question of polarization of fast neutrons came up in 50's. The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li (p,n) 7 Be, T(p,n) 3 He reactions. (authors)

  4. Best-feeding the baby

    African Journals Online (AJOL)

    Enrique

    Best-feeding the baby. Human infants should be fed their own mothers' breast- milk. Where this is unavailable, replacement feeding becomes necessary. Through the ages and right up to the present, human milk has been supplied by other lactating women within or from outside the family. Donated breast-milk has been ...

  5. A Compact Design of Planar Array Antenna with Fractal Elements for Future Generation Applications

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2016-01-01

    In this paper, a planar phased array fractal antenna for the future fifth generation (5G) applications is presented. The proposed array antenna is designed to operate at 22 GHz. 64 patch antenna elements with coaxial-probe feeds have been used for the proposed design. The antenna elements are based...... on Vicsek fractal geometry where the third iteration patches operate over a wide bandwidth and contribute to improve the efficiency and realized gain performance. The designed planar array has more than 22 dB realized gain and -0.3 dB total efficiency when its beam is tilted to 0 degrees elevation...

  6. An Optimal Beamforming Algorithm for Phased-Array Antennas Used in Multi-Beam Spaceborne Radiometers

    DEFF Research Database (Denmark)

    Iupikov, O. A.; Ivashina, M. V.; Pontoppidan, K.

    2015-01-01

    Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays...... to a FPA feeding a torus reflector antenna (designed under the contract with the European Space Agency) and tested for multiple beams. The results demonstrate an improved performance in terms of the optimized beam characteristics, yielding much higher spatial and radiometric resolution as well as much...

  7. Terahertz spectroscopic polarimetry of generalized anisotropic media composed of Archimedean spiral arrays: Experiments and simulations.

    Science.gov (United States)

    Aschaffenburg, Daniel J; Williams, Michael R C; Schmuttenmaer, Charles A

    2016-05-07

    Terahertz time-domain spectroscopic polarimetry has been used to measure the polarization state of all spectral components in a broadband THz pulse upon transmission through generalized anisotropic media consisting of two-dimensional arrays of lithographically defined Archimedean spirals. The technique allows a full determination of the frequency-dependent, complex-valued transmission matrix and eigenpolarizations of the spiral arrays. Measurements were made on a series of spiral array orientations. The frequency-dependent transmission matrix elements as well as the eigenpolarizations were determined, and the eigenpolarizations were found be to elliptically corotating, as expected from their symmetry. Numerical simulations are in quantitative agreement with measured spectra.

  8. A History of Infant Feeding

    Science.gov (United States)

    Stevens, Emily E; Patrick, Thelma E; Pickler, Rita

    2009-01-01

    The historical evolution of infant feeding includes wet nursing, the feeding bottle, and formula use. Before the invention of bottles and formula, wet nursing was the safest and most common alternative to the natural mother's breastmilk. Society's negative view of wet nursing, combined with improvements of the feeding bottle, the availability of animal's milk, and advances in formula development, gradually led to the substitution of artificial feeding for wet nursing. In addition, the advertising and safety of formula products increased their popularity and use among society. Currently, infant formula-feeding is widely practiced in the United States and appears to contribute to the development of several common childhood illnesses, including atopy, diabetes mellitus, and childhood obesity. PMID:20190854

  9. Radiation sterilization of livestock feeds

    International Nuclear Information System (INIS)

    Kawashima, Koji

    1984-01-01

    The radiation sterilization of livestock feeds is not much used presently because the process is not known well, and the cost is relatively high. However, its effect of sterilization is absolute, the radiation-sterilized feeds are safe in both nutrition and toxicity, and do not affect the appetite of livestocks, and the radiation energy required is small. In the future, as in the sterilization of medical supplies, feed radiation sterilization plants should be established, to stabilize livestock industry and to contribute to the health control of experimental animals. The following matters are described: radiation, comparison between radiation sterilization and other sterilization methods, the practice of feed radiation sterilization, the adverse effects of radiation sterilization, economic aspect, and the situation of feed radiation sterilization in various countries. (Mori, K.)

  10. Development of impedance matching technologies for ICRF antenna arrays

    International Nuclear Information System (INIS)

    Pinsker, R.I.

    1998-01-01

    All high-power ion cyclotron range of frequency (ICRF) heating systems include devices for matching the input impedance of the antenna array to the generator output impedance. For most types of antennas used, the input impedance is strongly time dependent on timescales as rapid as 10 -1 s, while the radio frequency (RF) generators used are capable of producing full power only into a stationary load impedance. Hence, the dynamic response of the matching method is of great practical importance. In this paper, world-wide developments in this field over the past decade are reviewed. These techniques may be divided into several classes. The edge plasma parameters that determine the antenna array's input impedance may be controlled to maintain a fixed load impedance. The frequency of the RF source can be feedback controlled to compensate for changes in the edge plasma conditions, or fast variable tuning elements in the transmission line between the generator output and the antenna input connections can provide the necessary time-varying impedance transformation. In 'lossy passive schemes', reflected power due to the time-varying impedance of the antenna array is diverted to a dummy load. Each of these techniques can be applied to a pre-existing antenna system. If a new antenna is to be designed, recent advances allow the antenna array to have the intrinsic property of presenting a constant load to the feeding transmission lines despite the varying load seen by each antenna in the array. (author)

  11. Development of impedance matching technologies for ICRF antenna arrays

    International Nuclear Information System (INIS)

    Pinsker, R.I.

    1998-03-01

    All high power ICRF heating systems include devices for matching the input impedance of the antenna array to the generator output impedance. For most types of antennas used, the input impedance is strongly time-dependent on timescales as rapid as 10-4 s, while the rf generators used are capable of producing full power only into a stationary load impedance. Hence, the dynamic response of the matching method is of great practical importance. In this paper, world-wide developments in this field over the past decade are reviewed. These techniques may be divided into several classes. The edge plasma parameters that determine the antenna array's input impedance may be controlled to maintain a fixed load impedance. The frequency of the rf source can be feedback controlled to compensate for changes in the edge plasma conditions, or fast variable tuning elements in the transmission line between the generator output and the antenna input connections can provide the necessary time-varying impedance transformation. In lossy passive schemes, reflected power due to the time-varying impedance of the antenna array is diverted to a dummy load. Each of these techniques can be applied to a pre-existing antenna system. If a new antenna is to be designed, recent advances allow the antenna array to have the intrinsic property of presenting a constant load to the feeding transmission lines despite the varying load seen by each antenna in the array

  12. Hierarchical sinuous-antenna phased array for millimeter wavelengths

    Science.gov (United States)

    Cukierman, Ari; Lee, Adrian T.; Raum, Christopher; Suzuki, Aritoki; Westbrook, Benjamin

    2018-03-01

    We present the design, fabrication, and measured performance of a hierarchical sinuous-antenna phased array coupled to superconducting transition-edge-sensor (TES) bolometers for millimeter wavelengths. The architecture allows for dual-polarization wideband sensitivity with a beam width that is approximately frequency-independent. We report on measurements of a prototype device, which uses three levels of triangular phased arrays to synthesize beams that are approximately constant in width across three frequency bands covering a 3:1 bandwidth. The array element is a lens-coupled sinuous antenna. The device consists of an array of hemispherical lenses coupled to a lithographed wafer, which integrates TESs, planar sinuous antennas, and microwave circuitry including band-defining filters. The approximately frequency-independent beam widths improve coupling to telescope optics and keep the sensitivity of an experiment close to optimal across a broad frequency range. The design can be straightforwardly modified for use with non-TES lithographed cryogenic detectors such as kinetic inductance detectors. Additionally, we report on the design and measurements of a broadband 180° hybrid that can simplify the design of future multichroic focal planes including but not limited to hierarchical phased arrays.

  13. Ecomorphological adaptations in Collembola in relation to feeding strategies and microhabitat

    NARCIS (Netherlands)

    Malcicka, Miriama; Berg, Matty P.; Ellers, Jacintha

    2017-01-01

    Some of the most important functional traits in animals are related to the potentially vast array of feeding strategies and microhabitat use. Correlated evolution of diet and habitat specialization with ecomorphological traits has been described in vertebrates, but such functional trait variation in

  14. Combinatorial aspects of covering arrays

    Directory of Open Access Journals (Sweden)

    Charles J. Colbourn

    2004-11-01

    Full Text Available Covering arrays generalize orthogonal arrays by requiring that t -tuples be covered, but not requiring that the appearance of t -tuples be balanced.Their uses in screening experiments has found application in software testing, hardware testing, and a variety of fields in which interactions among factors are to be identified. Here a combinatorial view of covering arrays is adopted, encompassing basic bounds, direct constructions, recursive constructions, algorithmic methods, and applications.

  15. Direct writing of large-area micro/nano-structural arrays on single crystalline germanium substrates using femtosecond lasers

    Science.gov (United States)

    Li, Lin; Wang, Jun

    2017-06-01

    A direct writing technique for fabricating micro/nano-structural arrays without using a multi-scanning process, multi-beam interference, or any assisted microlens arrays is reported. Various sub-wavelength micro/nano-structural arrays have been directly written on single crystalline germanium substrate surfaces using femtosecond laser pulses. The evolution of the multiscale surface morphology from periodic micro/nano-structures to V-shaped microgrooves has been achieved, and the relationship between array characteristics and laser polarization directions has been discussed. The self-organization model agrees well with the experimental results in this study.

  16. Nanoelectrode array for electrochemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yelton, William G [Sandia Park, NM; Siegal, Michael P [Albuquerque, NM

    2009-12-01

    A nanoelectrode array comprises a plurality of nanoelectrodes wherein the geometric dimensions of the electrode controls the electrochemical response, and the current density is independent of time. By combining a massive array of nanoelectrodes in parallel, the current signal can be amplified while still retaining the beneficial geometric advantages of nanoelectrodes. Such nanoelectrode arrays can be used in a sensor system for rapid, non-contaminating field analysis. For example, an array of suitably functionalized nanoelectrodes can be incorporated into a small, integrated sensor system that can identify many species rapidly and simultaneously under field conditions in high-resistivity water, without the need for chemical addition to increase conductivity.

  17. Array architectures for iterative algorithms

    Science.gov (United States)

    Jagadish, Hosagrahar V.; Rao, Sailesh K.; Kailath, Thomas

    1987-01-01

    Regular mesh-connected arrays are shown to be isomorphic to a class of so-called regular iterative algorithms. For a wide variety of problems it is shown how to obtain appropriate iterative algorithms and then how to translate these algorithms into arrays in a systematic fashion. Several 'systolic' arrays presented in the literature are shown to be specific cases of the variety of architectures that can be derived by the techniques presented here. These include arrays for Fourier Transform, Matrix Multiplication, and Sorting.

  18. Coronal Polarization of Pseudostreamers and the Solar Polar Field Reversal

    Science.gov (United States)

    Rachmeler, L. A.; Guennou, C.; Seaton, D. B.; Gibson, S. E.; Auchere, F.

    2016-01-01

    The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP polarization data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere, the last vestiges of the previous polar field polarity remained until March 2015. We present here the evolution of the structure and describe its identification in the Fe XII 1074nm coronal emission line, sensitive to the Hanle effect in the corona.

  19. System for measuring the proton polarization in a polarized target

    International Nuclear Information System (INIS)

    Karnaukhov, I.M.; Lukhanin, A.A.; Telegin, Yu.N.; Trotsenko, V.I.; Chechetenko, V.F.

    1984-01-01

    The system for measuring the proton polarization in a polarized target representing the high-sensitivity nuclear magnetic resonance (NMR) is described Q-meter with series connection and a circuit for measuring system resonance characteristic is used for NMR-absorption signal recording. Measuring coil is produced of a strip conductor in order to obtain uniform system sensitivity to polarization state in all target volume and improve signal-to-noise ratio. Polarization measuring system operates ion-line with the M-6000 computer. The total measuring error for the value of free proton polarization in target taking into account the error caused by local depolarization of working substance under irradiation by high-intense photon beam is <= 6%. Long-term application of the described system for measuring the proton polarization in the LUEh-20000 accelerator target used in the pion photoproduction experiments has demonstrated its high reliability

  20. Spin-polarized SEM

    International Nuclear Information System (INIS)

    Konoto, Makoto

    2007-01-01

    Development of highly effective evaluation technology of magnetic structures on a nanometric scale is a key to understanding spintronics and related phenomena. A high-resolution spin-polarized scanning electron microscope (spin SEM) developed recently is quite suitable for probing such nanostructures because of the capability of analyzing local magnetization vectors in three dimensions. Utilizing the spin SEM, a layered antiferromagnetic structure with the 1nm-alternation of bilayer-sheet magnetization has been successfully resolved. The real-space imaging with full analysis of the temperature-dependent magnetization vectors will be demonstrated. (author)