A kind of fast shutter for Z pinch diagnosis device

NASA Astrophysics Data System (ADS)

Wang, Liangping; Zhang, Xinjun; Sun, Tieping; Mao, Wentin

2016-09-01

A kind of fast shutter for protecting the diagnosis devices in Z pinch experiments is introduced in this paper. The shutter is composed of a pulling rod, a magnetic core, and a solenoid. Different from the traditional coils which were used at the voltage of 220 V, the solenoid we used must endure the high voltage of 5-10 kV and the deformation which maybe caused by the 5-10 T intense magnetic field. A creative configuration for the solenoid is developed including the winding guide, insulating sleeve, and stainless-steel sleeve. The experimental results show that the configuration of the solenoid is effective. The velocity of the valve is nearly 19 m/s and the time jitter of the shutdown is within 75 μs.

DC drive system for cine/pulse cameras

NASA Technical Reports Server (NTRS)

Gerlach, R. H.; Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

1977-01-01

Camera-drive functions are separated mechanically into two groups which are driven by two separate dc brushless motors. First motor, a 90 deg stepper, drives rotating shutter; second electronically commutated motor drives claw and film transport. Shutter is made of one piece but has two openings for slow and fast exposures.

ISOTOPE SEPARATORS

DOEpatents

Bacon, C.G.

1958-08-26

An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

Single-bunch synchrotron shutter

DOEpatents

Norris, James R.; Tang, Jau-Huei; Chen, Lin; Thurnauer, Marion

1993-01-01

An apparatus for selecting a single synchrotron pulse from the millions of pulses provided per second from a synchrotron source includes a rotating spindle located in the path of the synchrotron pulses. The spindle has multiple faces of a highly reflective surface, and having a frequency of rotation f. A shutter is spaced from the spindle by a radius r, and has an open position and a closed position. The pulses from the synchrotron are reflected off the spindle to the shutter such that the speed s of the pulses at the shutter is governed by: s=4.times..pi..times.r.times.f. such that a single pulse is selected for transmission through an open position of the shutter.

SECOND FLOOR FRONT ROOM, WINDOWS FACING ON WALNUT STREET (SOUTH), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

SECOND FLOOR FRONT ROOM, WINDOWS FACING ON WALNUT STREET (SOUTH), ORIGINAL PANELED FOLDING SHUTTERS AND HARDWARE. For a view of closed shutters see PA-1436 A-16 - Kid-Chandler House, 323 Walnut Street, Philadelphia, Philadelphia County, PA

FPGA Control System for the Automated Test of MicroShutters

NASA Technical Reports Server (NTRS)

Lyness, Eric; Rapchun, David A.; Moseley, S. Harvey

2008-01-01

The James Webb Space Telescope, scheduled to replace the Hubble in 2013, must simultaneously observe hundreds of faint galaxies. This requirement has led to the development of a programmable transmission mask which can be adapted to admit light from an arbitrary pattern of galaxies into its spectrograph. This programmable mask will contain a large array of micro-electromechanical (MEMs) devices called MicroShutters. These microscopic shutters physically open and close like the shutter on a camera, except each shutter is microscopic in size and an array 365 by 171 is used to select the objects under spectroscopic observation at a given time, and to block the unwanted background light from other areas. NASA developed and is currently refining the exceptionally difficult process of manufacturing these shutters. This paper describes how the authors used LabVIEW FPGA and a reconfigurable I/O board to control the shutters in a test chamber and how the flexibility of the system allows us to continue to modify the control algorithms as NASA optimizes the performance of the MicroShutter arrays.

High speed shutter. [electrically actuated ribbon loop for shuttering optical or fluid passageways

NASA Technical Reports Server (NTRS)

Mcclenahan, J. O. (Inventor)

1974-01-01

A shutter element is described which is formed by a loop of an electrically conductive ribbon disposed adjacent to the end of a passageway to be shuttered. The shuttered end of the passageway is cut at an acute angle. The two leg portions of the ribbon loop are closely spaced to each other and disposed in a plane parallel to the axis of the passageway. A pulse of high current is switched through the loop to cause the current flowing in opposite directions through adjacent leg portions of the ribbon. This produces a magnetically induced pressure on one of the legs of the ribbon forcing the leg over the end of the passageway in gas tight sealing engagement, and thereby blocking passageway.

MEMS Microshutter Arrays for James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Li, Mary J.; Beamesderfer, Michael; Babu, Sachi; Bajikar, Sateesh; Ewin, Audrey; Franz, Dave; Hess, Larry; Hu, Ron; Jhabvala, Murzy; Kelly, Dan;

Method and system for nanoscale plasma processing of objects

DOEpatents

Oehrlein, Gottlieb S [Clarksville, MD; Hua, Xuefeng [Hyattsville, MD; Stolz, Christian [Baden-Wuerttemberg, DE

2008-12-30

A plasma processing system includes a source of plasma, a substrate and a shutter positioned in close proximity to the substrate. The substrate/shutter relative disposition is changed for precise control of substrate/plasma interaction. This way, the substrate interacts only with a fully established, stable plasma for short times required for nanoscale processing of materials. The shutter includes an opening of a predetermined width, and preferably is patterned to form an array of slits with dimensions that are smaller than the Debye screening length. This enables control of the substrate/plasma interaction time while avoiding the ion bombardment of the substrate in an undesirable fashion. The relative disposition between the shutter and the substrate can be made either by moving the shutter or by moving the substrate.

FPGA Control System for the Automated Test of Microshutters

NASA Technical Reports Server (NTRS)

Lyness, Eric; Rapchun, David A.; Moseley, S. Harvey

2008-01-01

The James Webb Space Telescope, scheduled to replace the Hubble in 2013, must simultaneously observe hundreds of faint galaxies. This requirement has led to the development of a programmable transmission mask which can be adapted to admit light with arbitrary pattern of galaxies into its spectrograph. This programmable mask will contain a large array of micro-electromechanical (MEMs) devices called MicroShutters. These microscopic shutters physically open and close like the shutter on a camera, except each shutter is microscopic in size and an array 365 by 171 is used to select the objects under spectroscopic observation at a given time, and to block the unwanted background light from other areas. NASA developed and is currently refining the exceptionally difficult process of manufacturing these shutters. This paper describes how the authors used LabVIEW FPGA and a reconfigurable I/O board to control the shutters in a test chamber and how the flexibility of the system allows us to continue to modify the control algorithms as NASA optimizes the performance of the MicroShutter arrays.

Structural Analysis of a Magnetically Actuated Silicon Nitride Micro-Shutter for Space Applications

NASA Technical Reports Server (NTRS)

Loughlin, James P.; Fettig, Rainer K.; Moseley, S. Harvey; Kutyrev, Alexander S.; Mott, D. Brent; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

Finite element models have been created to simulate the electrostatic and electromagnetic actuation of a 0.5 micrometers silicon nitride micro-shutter for use in a spacebased Multi-object Spectrometer (MOS). The microshutter uses a torsion hinge to go from the closed, 0 degree, position, to the open, 90 degree position. Stresses in the torsion hinge are determined with a large deformation nonlinear finite element model. The simulation results are compared to experimental measurements of fabricated micro-shutter devices.

Programmable Aperture with MEMS Microshutter Arrays

NASA Technical Reports Server (NTRS)

Moseley, Samuel; Li, Mary; Kutyrev, Alexander; Kletetschka, Gunther; Fettig, Rainer

2011-01-01

A microshutter array (MSA) has been developed for use as an aperture array for multi-object selections in James Webb Space Telescope (JWST) technology. Light shields, molybdenum nitride (MoN) coating on shutters, and aluminum/aluminum oxide coatings on interior walls are put on each shutter for light leak prevention, and to enhance optical contrast. Individual shutters are patterned with a torsion flexure that permits shutters to open 90 deg. with a minimized mechanical stress concentration. The shutters are actuated magnetically, latched, and addressed electrostatically. Also, micromechanical features are tailored onto individual shutters to prevent stiction. An individual shutter consists of a torsion hinge, a shutter blade, a front electrode that is coated on the shutter blade, a backside electrode that is coated on the interior walls, and a magnetic cobalt-iron coating. The magnetic coating is patterned into stripes on microshutters so that shutters can respond to an external magnetic field for the magnetic actuation. A set of column electrodes is placed on top of shutters, and a set of row electrodes on sidewalls is underneath the shutters so that they can be electrostatically latched open. A linear permanent magnet is aligned with the shutter rows and is positioned above a flipped upside-down array, and sweeps across the array in a direction parallel to shutter columns. As the magnet sweeps across the array, sequential rows of shutters are rotated from their natural horizontal orientation to a vertical open position, where they approach vertical electrodes on the sidewalls. When the electrodes are biased with a sufficient electrostatic force to overcome the mechanical restoring force of torsion bars, shutters remain latched to vertical electrodes in their open state. When the bias is removed, or is insufficient, the shutters return to their horizontal, closed positions. To release a shutter, both the electrode on the shutter and the one on the back wall where the shutter sits are grounded. The shutters with one or both ungrounded electrodes are held open. Sub-micron bumps underneath light shields and silicon ribs on back walls are the two features to prevent stiction. These features ensure that the microshutter array functions properly in mechanical motions. The MSA technology can be used primarily in multi-object imaging and spectroscopy, photomask generation, light switches, and in the stepper equipment used to make integrated circuits and MEMS (microelectromechanical systems) devices.

Piezo-Operated Shutter Mechanism Moves 1.5 cm

NASA Technical Reports Server (NTRS)

Glaser, Robert; Bamford, Robert

2005-01-01

The figure shows parts of a shutter mechanism designed to satisfy a number of requirements specific to its original intended application as a component of an atomic clock to be flown in outer space. The mechanism may also be suitable for use in laboratory and industrial vacuum systems on Earth for which there are similar requirements. The requirements include the following: a) To alternately close, then open, a 1.5-cm-diameter optical aperture twice per second, with a stroke time of no more than 15 ms, during a total operational lifetime of at least a year; b) To attenuate light by a factor of at least 1012 when in the closed position; c) To generate little or no magnetic field; d) To be capable of withstanding bakeout at a temperature of 200 C to minimize outgassing during subsequent operation in an ultrahigh vacuum; and e) To fit within a diameter of 12 in. (=305 mm) a size limit dictated by the size of an associated magnetic shield. The light-attenuation requirement is satisfied by use of overlapping shutter blades. The closure of the aperture involves, among other things, insertion of a single shutter blade between a pair of shutter blades. The requirement to minimize the magnetic field is satisfied by use of piezoelectric actuators. Because piezoelectric actuators cannot withstand bakeout, they must be mounted outside the vacuum chamber, and, hence, motion must be transmitted from the actuators to the shutter levers via a vacuum-chamber-wall diaphragm.

Designing the optimal shutter sequences for the flutter shutter imaging method

NASA Astrophysics Data System (ADS)

Jelinek, Jan

2010-04-01

Acquiring iris or face images of moving subjects at larger distances using a flash to prevent the motion blur quickly runs into eye safety concerns as the acquisition distance is increased. For that reason the flutter shutter method recently proposed by Raskar et al.has generated considerable interest in the biometrics community. The paper concerns the design of shutter sequences that produce the best images. The number of possible sequences grows exponentially in both the subject' s motion velocity and desired exposure value, with their majority being useless. Because the exact solution leads to an intractable mixed integer programming problem, we propose an approximate solution based on pre - screening the sequences according to the distribution of roots in their Fourier transform. A very fast algorithm utilizing the Jury' s criterion allows the testing to be done without explicitly computing the roots, making the approach practical for moderately long sequences.

Synchronized Electronic Shutter System (SESS) for Thermal Nondestructive Evaluation

NASA Technical Reports Server (NTRS)

Zalameda, Joseph N.

2001-01-01

The purpose of this paper is to describe a new method for thermal nondestructive evaluation. This method uses a synchronized electronic shutter system (SESS) to remove the heat lamp's influence on the thermal data during and after flash heating. There are two main concerns when using flash heating. The first concern is during the flash when the photons are reflected back into the camera. This tends to saturate the detectors and potentially introduces unknown and uncorrectable errors when curve fitting the data to a model. To address this, an electronically controlled shutter was placed over the infrared camera lens. Before firing the flash lamps, the shutter is opened to acquire the necessary background data for offset calibration. During flash heating, the shutter is closed to prevent the photons from the high intensity flash from saturating the camera's detectors. The second concern is after the flash heating where the lamps radiate heat after firing. This residual cooling introduces an unwanted transient thermal response into the data. To remove this residual effect, a shutter was placed over the flash lamps to block the infrared heat radiating from the flash head after heating. This helped to remove the transient contribution of the flash. The flash lamp shutters were synchronized electronically with the camera shutter. Results are given comparing the use of the thermal inspection with and without the shutter system.

Testing Microshutter Arrays Using Commercial FPGA Hardware

NASA Technical Reports Server (NTRS)

Rapchun, David

2008-01-01

NASA is developing micro-shutter arrays for the Near Infrared Spectrometer (NIRSpec) instrument on the James Webb Space Telescope (JWST). These micro-shutter arrays allow NIRspec to do Multi Object Spectroscopy, a key part of the mission. Each array consists of 62414 individual 100 x 200 micron shutters. These shutters are magnetically opened and held electrostatically. Individual shutters are then programmatically closed using a simple row/column addressing technique. A common approach to provide these data/clock patterns is to use a Field Programmable Gate Array (FPGA). Such devices require complex VHSIC Hardware Description Language (VHDL) programming and custom electronic hardware. Due to JWST's rapid schedule on the development of the micro-shutters, rapid changes were required to the FPGA code to facilitate new approaches being discovered to optimize the array performance. Such rapid changes simply could not be made using conventional VHDL programming. Subsequently, National Instruments introduced an FPGA product that could be programmed through a Labview interface. Because Labview programming is considerably easier than VHDL programming, this method was adopted and brought success. The software/hardware allowed the rapid change the FPGA code and timely results of new micro-shutter array performance data. As a result, numerous labor hours and money to the project were conserved.

Elastic Distribution of Microshutters, Measurements Obtainable on James Web Space Telescope

NASA Technical Reports Server (NTRS)

Kletetschka, Gunther; King, Todd; Mikula, Vilem

2008-01-01

Spectrographic astronomy measurements in the near-infrared region will be done by functional two-dimensional microshutter arrays that are being fabricated at the NASA Goddard Space Flight Center for the James Webb Space Telescope (JWST). These micro-shutter arrays will represent the first mission-critical MEMS devices to be flown in space. JWST will use microshutter arrays to select focal plane object. 2-D programmable aperture masks of more than 200,000 elements select such space object. The use of silicon wafer material promises high efficiency and high contrast. Microshutter operation temperature is around 35K. Microshutter arrays are fabricated as close-packed silicon nitride membranes with a unit cell size of 105 x 204 micrometers. A layer of magnetic material is deposited onto each shutter. Individual shutters are equipped with a torsion flexure. Reactive ion etching (RIE) releases the shutters so they can open up to 90 degrees using the torsion flexure. Shutter rotation is initiated into a silicon support structure via an external magnetic field. Two electrically independent aluminum electrodes are deposited, one onto each shutter and another onto the support structure side-wall, permitting electrostatic latching and 2-D addressing to hold specific shutters open via external electronics.

An ultra-fast optical shutter exploiting total light absorption in a phase change material

NASA Astrophysics Data System (ADS)

Jafari, Mohsen; Guo, L. Jay; Rais-Zadeh, Mina

2017-02-01

In this paper, we present an ultra-fast and high-contrast optical shutter with applications in atomic clock assemblies, integrated photonic systems, communication hardware, etc. The shutter design exploits the total light absorption phenomenon in a thin phase change (PC) material placed over a metal layer. The shutter switches between ON and OFF states by changing PC material phase and thus its refractive index. The PC material used in this work is Germanium Telluride (GeTe), a group IV-VI chalcogenide compound, which exhibits good optical contrast when switching from amorphous to crystalline state and vice versa. The stable phase changing behavior and reliability of GeTe and GeSbTe (GST) have been verified in optical memories and RF switches. Here, GeTe is used as it has a lower extinction coefficient in near-IR regions compared to GST. GeTe can be thermally transitioned between two phases by applying electrical pulses to an integrated heater. The memory behavior of GeTe results in zero static power consumption which is useful in applications requiring long time periods between switching activities. We previously demonstrated a meta-surface employing GeTe in sub-wavelength slits with >14 dB isolation at 1.5 μm by exciting the surface plasmon polariton and localized slit resonances. In this work, strong interference effects in a thin layer of GeTe over a gold mirror result in near total light absorption of up to 40 dB (21 dB measured) in the amorphous phase of the shutter at 780 nm with much less fabrication complexity. The optical loss at the shutter ON state is less than 1.5 dB. A nickel chrome (NiCr) heater provides the Joule heating energy required to achieve the crystallographic phase change. The measured switching speed is 2 μs.

A fast double shutter for CCD-based metrology

NASA Astrophysics Data System (ADS)

Geisler, R.

2017-02-01

Image based metrology such as Particle Image Velocimetry (PIV) depends on the comparison of two images of an object taken in fast succession. Cameras for these applications provide the so-called `double shutter' mode: One frame is captured with a short exposure time and in direct succession a second frame with a long exposure time can be recorded. The difference in the exposure times is typically no problem since illumination is provided by a pulsed light source such as a laser and the measurements are performed in a darkened environment to prevent ambient light from accumulating in the long second exposure time. However, measurements of self-luminous processes (e.g. plasma, combustion ...) as well as experiments in ambient light are difficult to perform and require special equipment (external shutters, highspeed image sensors, multi-sensor systems ...). Unfortunately, all these methods incorporate different drawbacks such as reduced resolution, degraded image quality, decreased light sensitivity or increased susceptibility to decalibration. In the solution presented here, off-the-shelf CCD sensors are used with a special timing to combine neighbouring pixels in a binning-like way. As a result, two frames of short exposure time can be captured in fast succession. They are stored in the on-chip vertical register in a line-interleaved pattern, read out in the common way and separated again by software. The two resultant frames are completely congruent; they expose no insensitive lines or line shifts and thus enable sub-pixel accurate measurements. A third frame can be captured at the full resolution analogue to the double shutter technique. Image based measurement techniques such as PIV can benefit from this mode when applied in bright environments. The third frame is useful e.g. for acceleration measurements or for particle tracking applications.

Programmable optical microshutter arrays for large aspect ratio microslits

NASA Astrophysics Data System (ADS)

Ilias, S.; Picard, F.; Larouche, C.; Kruzelecky, R.; Jamroz, W.; Le Noc, L.; Topart, P.

2008-06-01

Design, fabrication and characterization of a 16x1 programmable microshutter array are described. Each shutter controls the light transmitted through a microslit defined on the transparent substrate supporting the array. Two approaches were considered for the shutter array implementation: sweeping blades and zipping actuators. Simulation results and fabrication constraints led to the selection of the zipping actuators. The device was fabricated using a surface micromachining process. Each microshutter is basically an electrostatic zipping actuator having a curved shape induced by a stress gradient throughout the actuator thickness. When a sufficient voltage is applied between the microshutter and an actuation electrode surrounding the microslit area, the generated electrostatic force pulls the actuator down to the substrate which closes the microslit. Opening the slit relies on the restoring force due to the actuator deformation. Microshutter arrays were fabricated successfully. High light transmission through the slit area is obtained with the actuator in the open position and excellent light blocking is observed when the shutter is closed. Static and dynamic responses of the device were determined. A pull-in voltage of about 110 V closes the microslit and the response times to close and open the microslit are about 2 and 7 ms, respectively.

Radiological implications of top-off operation at national synchrotron light source-II

NASA Astrophysics Data System (ADS)

Job, P. K.; Casey, W. R.

2011-08-01

High current and low emittance have been specified to achieve ultra high brightness in the third generation medium energy Synchrotron Radiation Sources. This leads to the electron beam lifetime limited by Touschek scattering, and after commissioning may settle in at as low as ∼3 h. It may well be less in the early days of operation. At the same time, the intensity stability specified by the user community for the synchrotron beam is 1% or better. Given the anticipated lifetime of the beam, incremental filling called top-off injection at intervals on the order of ∼1 min will be required to maintain this beam stability. It is judged to be impractical to make these incremental fills by closing the beam shutters at each injection. In addition, closing the front end beam shutters during each injection will adversely affect the stability of beamline optics due to thermal cycling. Hence the radiological consequences of injection with front end beam shutters open must be evaluated. This paper summarizes results of radiological analysis carried out for the proposed top-off injection at National Synchrotron Light Source-II (NSLS-II) with beam shutters open.

Microsecond-range optical shutter for unpolarized light with chiral nematic liquid crystal

NASA Astrophysics Data System (ADS)

Mohammadimasoudi, Mohammad; Shin, Jungsoon; Lee, Keechang; Neyts, Kristiaan; Beeckman, Jeroen

2015-04-01

A fast electro-optic shutter is fabricated and demonstrated. The device works independently of the polarization state of the incoming light beam. Modulation between 3% transmission and 60% transmission is obtained within a wavelength range of 50 nm with a response time of 20 μs. The device consists of two partly polymerized chiral nematic liquid crystal layers separated by a half wave plate. The transmission modulation is due to a 50 nm wavelength shift of the photonic band gap of the chiral liquid crystal realized by applying an electric field over a mixture of photo-polymerized LC and non-reactive nematic LC containing a chiral dopant. The shutter features high reflectivity in the photonic band gap. We investigate the influence of the amplitude of the applied voltage on the width and the depth of the reflection band.

High speed photography, videography, and photonics III; Proceedings of the Meeting, San Diego, CA, August 22, 23, 1985

NASA Technical Reports Server (NTRS)

Ponseggi, B. G. (Editor); Johnson, H. C. (Editor)

1985-01-01

Papers are presented on the picosecond electronic framing camera, photogrammetric techniques using high-speed cineradiography, picosecond semiconductor lasers for characterizing high-speed image shutters, the measurement of dynamic strain by high-speed moire photography, the fast framing camera with independent frame adjustments, design considerations for a data recording system, and nanosecond optical shutters. Consideration is given to boundary-layer transition detectors, holographic imaging, laser holographic interferometry in wind tunnels, heterodyne holographic interferometry, a multispectral video imaging and analysis system, a gated intensified camera, a charge-injection-device profile camera, a gated silicon-intensified-target streak tube and nanosecond-gated photoemissive shutter tubes. Topics discussed include high time-space resolved photography of lasers, time-resolved X-ray spectrographic instrumentation for laser studies, a time-resolving X-ray spectrometer, a femtosecond streak camera, streak tubes and cameras, and a short pulse X-ray diagnostic development facility.

Microsecond-range optical shutter for unpolarized light with chiral nematic liquid crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohammadimasoudi, Mohammad, E-mail: Mohammad.Mohammadimasoudi@elis.ugent.be; Neyts, Kristiaan; Beeckman, Jeroen

2015-04-15

A fast electro-optic shutter is fabricated and demonstrated. The device works independently of the polarization state of the incoming light beam. Modulation between 3% transmission and 60% transmission is obtained within a wavelength range of 50 nm with a response time of 20 μs. The device consists of two partly polymerized chiral nematic liquid crystal layers separated by a half wave plate. The transmission modulation is due to a 50 nm wavelength shift of the photonic band gap of the chiral liquid crystal realized by applying an electric field over a mixture of photo-polymerized LC and non-reactive nematic LC containingmore » a chiral dopant. The shutter features high reflectivity in the photonic band gap. We investigate the influence of the amplitude of the applied voltage on the width and the depth of the reflection band.« less

Confocal multispot microscope for fast and deep imaging in semicleared tissues

NASA Astrophysics Data System (ADS)

Adam, Marie-Pierre; Müllenbroich, Marie Caroline; Di Giovanna, Antonino Paolo; Alfieri, Domenico; Silvestri, Ludovico; Sacconi, Leonardo; Pavone, Francesco Saverio

2018-02-01

Although perfectly transparent specimens are imaged faster with light-sheet microscopy, less transparent samples are often imaged with two-photon microscopy leveraging its robustness to scattering; however, at the price of increased acquisition times. Clearing methods that are capable of rendering strongly scattering samples such as brain tissue perfectly transparent specimens are often complex, costly, and time intensive, even though for many applications a slightly lower level of tissue transparency is sufficient and easily achieved with simpler and faster methods. Here, we present a microscope type that has been geared toward the imaging of semicleared tissue by combining multispot two-photon excitation with rolling shutter wide-field detection to image deep and fast inside semicleared mouse brain. We present a theoretical and experimental evaluation of the point spread function and contrast as a function of shutter size. Finally, we demonstrate microscope performance in fixed brain slices by imaging dendritic spines up to 400-μm deep.

Design and realization of an AEC&AGC system for the CCD aerial camera

NASA Astrophysics Data System (ADS)

Liu, Hai ying; Feng, Bing; Wang, Peng; Li, Yan; Wei, Hao yun

2015-08-01

An AEC and AGC(Automatic Exposure Control and Automatic Gain Control) system was designed for a CCD aerial camera with fixed aperture and electronic shutter. The normal AEC and AGE algorithm is not suitable to the aerial camera since the camera always takes high-resolution photographs in high-speed moving. The AEC and AGE system adjusts electronic shutter and camera gain automatically according to the target brightness and the moving speed of the aircraft. An automatic Gamma correction is used before the image is output so that the image is better for watching and analyzing by human eyes. The AEC and AGC system could avoid underexposure, overexposure, or image blurring caused by fast moving or environment vibration. A series of tests proved that the system meet the requirements of the camera system with its fast adjusting speed, high adaptability, high reliability in severe complex environment.

Towards Kilo-Hertz 6-DoF Visual Tracking Using an Egocentric Cluster of Rolling Shutter Cameras.

PubMed

Bapat, Akash; Dunn, Enrique; Frahm, Jan-Michael

2016-11-01

To maintain a reliable registration of the virtual world with the real world, augmented reality (AR) applications require highly accurate, low-latency tracking of the device. In this paper, we propose a novel method for performing this fast 6-DOF head pose tracking using a cluster of rolling shutter cameras. The key idea is that a rolling shutter camera works by capturing the rows of an image in rapid succession, essentially acting as a high-frequency 1D image sensor. By integrating multiple rolling shutter cameras on the AR device, our tracker is able to perform 6-DOF markerless tracking in a static indoor environment with minimal latency. Compared to state-of-the-art tracking systems, this tracking approach performs at significantly higher frequency, and it works in generalized environments. To demonstrate the feasibility of our system, we present thorough evaluations on synthetically generated data with tracking frequencies reaching 56.7 kHz. We further validate the method's accuracy on real-world images collected from a prototype of our tracking system against ground truth data using standard commodity GoPro cameras capturing at 120 Hz frame rate.

A new 9T global shutter pixel with CDS technique

NASA Astrophysics Data System (ADS)

Liu, Yang; Ma, Cheng; Zhou, Quan; Wang, Xinyang

2015-04-01

Benefiting from motion blur free, Global shutter pixel is very widely used in the design of CMOS image sensors for high speed applications such as motion vision, scientifically inspection, etc. In global shutter sensors, all pixel signal information needs to be stored in the pixel first and then waiting for readout. For higher frame rate, we need very fast operation of the pixel array. There are basically two ways for the in pixel signal storage, one is in charge domain, such as the one shown in [1], this needs complicated process during the pixel fabrication. The other one is in voltage domain, one example is the one in [2], this pixel is based on the 4T PPD technology and normally the driving of the high capacitive transfer gate limits the speed of the array operation. In this paper we report a new 9T global shutter pixel based on 3-T partially pinned photodiode (PPPD) technology. It incorporates three in-pixel storage capacitors allowing for correlated double sampling (CDS) and pipeline operation of the array (pixel exposure during the readout of the array). Only two control pulses are needed for all the pixels at the end of exposure which allows high speed exposure control.

Quantitative Single-Ion Irradiation by ASIPP Microbeam

NASA Astrophysics Data System (ADS)

Wang, Xu-Fei; Chen, Lian-Yun; Hu, Zhi-Wen; Wang, Xiao-Hua; Zhang, Jun; Li, Jun; Chen, Bin; Hu, Su-Hua; Shi, Zhong-Tao; Wu, Yu; Xu, Ming-Liang; Wu, Li-Jun; Wang, Shao-Hu; Yu, Zeng-Liang

2004-05-01

A single-ion microbeam facility has been constructed by the microbeam research group in ASIPP (Institute of Plasma Physics, Chinese Academy of Science). The system was designed to deliver defined numbers of hydrogen ions produced by a van de Graaff accelerator, covering an energy range from 200 keV to 3 MeV, into living cells (5 mum-20 mum diameter) growing in culture on thin plastic films. The beam is collimated by a 1- mum inner diameter HPLC (high performance liquid chromatography) capillary, which forms the micron-dimensional beam-line exit. A microbeam collimator, a scintillation ion counting system and a fast beam shutter, which constitute a precise dosage measuring and controlling system, jointly perform quantitative single-ion irradiation. With this facility, we can presently acquire ion-hitting efficiency close to 95%.

School Closings No Fiscal Savior, Study Cautions

ERIC Educational Resources Information Center

Samuels, Christina A.

2011-01-01

If big-city districts are looking to close budget gaps, shuttering schools may not be the best strategy. Closing schools does not save very much money in the context of an urban district's budget, and selling or leasing surplus school buildings tends to be difficult because they're often old and in struggling neighborhoods, a recent report from a…

Large area and low power dielectrowetting optical shutter with local deterministic fluid film breakup

NASA Astrophysics Data System (ADS)

Zhao, R.; Cumby, B.; Russell, A.; Heikenfeld, J.

2013-11-01

A large area (>10 cm2) and low-power (0.1-10 Hz AC voltage, ˜10's μW/cm2) dielectrowetting optical shutter requiring no pixelation is demonstrated. The device consists of 40 μm interdigitated electrodes covered by fluid splitting features and a hydrophobic fluoropolymer. When voltage is removed, the fluid splitting features initiate breakup of the fluid film into small droplets resulting in ˜80% transmission. Both the dielectrowetting and fluid splitting follow theory, allowing prediction of alternate designs and further improved performance. Advantages include scalability, optical polarization independence, high contrast ratio, fast response, and simple construction, which could be of use in switchable windows or transparent digital signage.

MEMS Microshutter Array System for James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Li, Mary J.; Adachi, Tomoko; Allen, Christine; Babu, Sachi; Bajikar, Sateesh; Beamesderfer, Michael; Bradley, Ruth; Denis, Kevin; Costen, Nick; Ewin, Audrey;

Time-resolved spectroscopy using a chopper wheel as a fast shutter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shicong; Wendt, Amy E.; Boffard, John B.

Widely available, small form-factor, fiber-coupled spectrometers typically have a minimum exposure time measured in milliseconds, and thus cannot be used directly for time-resolved measurements at the microsecond level. Spectroscopy at these faster time scales is typically done with an intensified charge coupled device (CCD) system where the image intensifier acts as a “fast” electronic shutter for the slower CCD array. In this paper, we describe simple modifications to a commercially available chopper wheel system to allow it to be used as a “fast” mechanical shutter for gating a fiber-coupled spectrometer to achieve microsecond-scale time-resolved optical measurements of a periodically pulsedmore » light source. With the chopper wheel synchronized to the pulsing of the light source, the time resolution can be set to a small fraction of the pulse period by using a chopper wheel with narrow slots separated by wide spokes. Different methods of synchronizing the chopper wheel and pulsing of the light sources are explored. The capability of the chopper wheel system is illustrated with time-resolved measurements of pulsed plasmas.« less

Electrophysiological measurement of interest during walking in a simulated environment.

PubMed

Takeda, Yuji; Okuma, Takashi; Kimura, Motohiro; Kurata, Takeshi; Takenaka, Takeshi; Iwaki, Sunao

2014-09-01

A reliable neuroscientific technique for objectively estimating the degree of interest in a real environment is currently required in the research fields of neuroergonomics and neuroeconomics. Toward the development of such a technique, the present study explored electrophysiological measures that reflect an observer's interest in a nearly-real visual environment. Participants were asked to walk through a simulated shopping mall and the attractiveness of the shopping mall was manipulated by opening and closing the shutters of stores. During the walking task, participants were exposed to task-irrelevant auditory probes (two-stimulus oddball sequence). The results showed a smaller P2/early P3a component of task-irrelevant auditory event-related potentials and a larger lambda response of eye-fixation-related potentials in an interesting environment (i.e., open-shutter condition) than in a boring environment (i.e., closed-shutter condition); these findings can be reasonably explained by supposing that participants allocated more attentional resources to visual information in an interesting environment than in a boring environment, and thus residual attentional resources that could be allocated to task-irrelevant auditory probes were reduced. The P2/early P3a component and the lambda response may be useful measures of interest in a real visual environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Cryogenic Characterization and Testing of Magnetically-Actuated Microshutter Arrays for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

King, T. T.; Kletetschka, G.; Jah, M. A.; Li, M. J.; Jhabvala, M. D.; Wang, L. L.; Beamesderfer, M. A.; Kutyrev, A. S.; Silverberg, R. F.; Rapchun, D.;

Development and Operation of the Microshutter Array System

NASA Technical Reports Server (NTRS)

Jhabvala, M. D.; Franz, D.; King, T.; Kletetschka, G.; Kutyrev, A. S.; Li, M. J.

2008-01-01

The microshutter array (MSA) is a key component in the James Webb Space Telescope Near Infrared Spectrometer (NIRSpec) instrument. The James Webb Space Telescope is the next generation of a space-borne astronomy platform that is scheduled to be launched in 2013. However, in order to effectively operate the array and meet the severe operational requirements associated with a space flight mission has placed enormous constraints on the microshutter array subsystem. This paper will present an overview and description of the entire microshutter subsystem including the microshutter array, the hybridized array assembly, the integrated CMOS electronics, mechanical mounting module and the test methodology and performance of the fully assembled microshutter subsystem. The NIRSpec is a European Space Agency (ESA) instrument requiring four fully assembled microshutter arrays, or quads, which are independently addressed to allow for the imaging of selected celestial objects onto the two 4 mega pixel IR detectors. Each microshutter array must have no more than approx.8 shutters which are failed in the open mode (depending on how many are failed closed) out of the 62,415 (365x171) total number of shutters per array. The driving science requirement is to be able to select up to 100 objects at a time to be spectrally imaged at the focal plane. The spectrum is dispersed in the direction of the 171 shutters so if there is an unwanted open shutter in that row the light from an object passing through that failed open shutter will corrupt the spectrum from the intended object.

A 75-ps Gated CMOS Image Sensor with Low Parasitic Light Sensitivity

PubMed Central

Zhang, Fan; Niu, Hanben

2016-01-01

In this study, a 40 × 48 pixel global shutter complementary metal-oxide-semiconductor (CMOS) image sensor with an adjustable shutter time as low as 75 ps was implemented using a 0.5-μm mixed-signal CMOS process. The implementation consisted of a continuous contact ring around each p+/n-well photodiode in the pixel array in order to apply sufficient light shielding. The parasitic light sensitivity of the in-pixel storage node was measured to be 1/8.5 × 107 when illuminated by a 405-nm diode laser and 1/1.4 × 104 when illuminated by a 650-nm diode laser. The pixel pitch was 24 μm, the size of the square p+/n-well photodiode in each pixel was 7 μm per side, the measured random readout noise was 217 e− rms, and the measured dynamic range of the pixel of the designed chip was 5500:1. The type of gated CMOS image sensor (CIS) that is proposed here can be used in ultra-fast framing cameras to observe non-repeatable fast-evolving phenomena. PMID:27367699

A 75-ps Gated CMOS Image Sensor with Low Parasitic Light Sensitivity.

PubMed

Zhang, Fan; Niu, Hanben

2016-06-29

In this study, a 40 × 48 pixel global shutter complementary metal-oxide-semiconductor (CMOS) image sensor with an adjustable shutter time as low as 75 ps was implemented using a 0.5-μm mixed-signal CMOS process. The implementation consisted of a continuous contact ring around each p+/n-well photodiode in the pixel array in order to apply sufficient light shielding. The parasitic light sensitivity of the in-pixel storage node was measured to be 1/8.5 × 10⁷ when illuminated by a 405-nm diode laser and 1/1.4 × 10⁴ when illuminated by a 650-nm diode laser. The pixel pitch was 24 μm, the size of the square p+/n-well photodiode in each pixel was 7 μm per side, the measured random readout noise was 217 e(-) rms, and the measured dynamic range of the pixel of the designed chip was 5500:1. The type of gated CMOS image sensor (CIS) that is proposed here can be used in ultra-fast framing cameras to observe non-repeatable fast-evolving phenomena.

Nano-stepper-driven optical shutter for applications in free-space micro-optics

NASA Astrophysics Data System (ADS)

Zawadzka, Justyna; Li, Lijie; Unamuno, Anartz; Uttamchandani, Deepak G.

2002-09-01

In this paper we report a simple design of a micro-optical shutter/attenuator. The standard MUMPS process was used to fabricate the device. A vertically erected, gold-coated, 200x300 mm side length micro-mirror was precisely placed between the end faces of two closely spaced optical fibers. The position of the micro-mirror with respect to the optical fiber end face was controlled by a nano-stepping motor array. Optical and mechanical tests were performed on the device. A 1.55 mm laser beam was sent along the optical fiber. When the micro-mirror was removed from the front of the fiber, the coupling efficiency between two fibers was -10 dBm. Once the micro-mirror was placed in the optical path the coupling efficiency dropped to -51.5 dBm. The best attenuation was obtained when the micro-mirror blocked the whole cross-section of the laser beam diameter. It is evident that the device can operate as a high precision fiber optic attenuator or shutter.

A Possible Method for the Discrimination of Spurious Events in Scintillation Chambers--Preliminary Results. Note No. 215; UN POSSIBILE METODO PER LA DISCRIMINAZIONE DI EVENTI SPURI IN CAMERA A SCINTILLE--RISULTATI PRELIMINARI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habel, R.; Letardi, T.

1963-10-30

In some studies with scintillation chambers, the problem of discriminating between the events generated by one or more ionizing particles and a spontaneous shower between the gaps of the chamber is presented. One element of difference between the two events is the delay of the spurious scintillation with respect to that produced by passage of a particle. The use of a fast shutter whose open time is of the order of the delay would provide a possible method for the discrimination between true and spurious events. The experimental apparatus used and the types of measurements made to determine if suchmore » a shutter arrangement would be feasible are described. (J.S.R.)« less

Shutterless ion mobility spectrometer with fast pulsed electron source

NASA Astrophysics Data System (ADS)

Bunert, E.; Heptner, A.; Reinecke, T.; Kirk, A. T.; Zimmermann, S.

2017-02-01

Ion mobility spectrometers (IMS) are devices for fast and very sensitive trace gas analysis. The measuring principle is based on an initial ionization process of the target analyte. Most IMS employ radioactive electron sources, such as 63Ni or 3H. These radioactive materials have the disadvantage of legal restrictions and the electron emission has a predetermined intensity and cannot be controlled or disabled. In this work, we replaced the 3H source of our IMS with 100 mm drift tube length with our nonradioactive electron source, which generates comparable spectra to the 3H source. An advantage of our emission current controlled nonradioactive electron source is that it can operate in a fast pulsed mode with high electron intensities. By optimizing the geometric parameters and developing fast control electronics, we can achieve very short electron emission pulses for ionization with high intensities and an adjustable pulse width of down to a few nanoseconds. This results in small ion packets at simultaneously high ion densities, which are subsequently separated in the drift tube. Normally, the required small ion packet is generated by a complex ion shutter mechanism. By omitting the additional reaction chamber, the ion packet can be generated directly at the beginning of the drift tube by our pulsed nonradioactive electron source with only slight reduction in resolving power. Thus, the complex and costly shutter mechanism and its electronics can also be omitted, which leads to a simple low-cost IMS-system with a pulsed nonradioactive electron source and a resolving power of 90.

9. FIRST FLOOR, EAST ROOM, NORTHEAST WALL, SHOWING DOORWAYS TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. FIRST FLOOR, EAST ROOM, NORTHEAST WALL, SHOWING DOORWAYS TO BOXED WINDER STAIRWAYS, UP ON FAR RIGHT AND DOWN TO RIGHT OF FIREPLACE, WITH SHUTTERS OVER FIREPLACE CLOSED - High Farm, House, Creek Road, 1 mile West of Easton Road, Pipersville, Bucks County, PA

Ion detection device and method with compressing ion-beam shutter

DOEpatents

Sperline, Roger P [Tucson, AZ

2009-05-26

An ion detection device, method and computer readable medium storing instructions for applying voltages to shutter elements of the detection device to compress ions in a volume defined by the shutter elements and to output the compressed ions to a collector. The ion detection device has a chamber having an inlet and receives ions through the inlet, a shutter provided in the chamber opposite the inlet and configured to allow or prevent the ions to pass the shutter, the shutter having first and second shutter elements, a collector provided in the chamber opposite the shutter and configured to collect ions passed through the shutter, and a processing unit electrically connected to the first and second shutter elements. The processing unit applies, during a first predetermined time interval, a first voltage to the first shutter element and a second voltage to the second shutter element, the second voltage being lower than the first voltage such that ions from the inlet enter a volume defined by the first and second shutter elements, and during a second predetermined time interval, a third voltage to the first shutter element, higher than the first voltage, and a fourth voltage to the second shutter element, the third voltage being higher than the fourth voltage such that ions that entered the volume are compressed as the ions exit the volume and new ions coming from the inlet are prevented from entering the volume. The processing unit is electrically connected to the collector and configured to detect the compressed ions based at least on a current received from the collector and produced by the ions collected by the collector.

Dosimetry in Thermal Neutron Irradiation Facility at BMRR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, J. P.; Holden, N. E.; Reciniello, R. N.

Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; includingmore » (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D 2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4 - 7 % lower than the statistical mean derived from the Monte-Carlo modeling (5% uncertainty). The dose rate measured by ion chambers was 6 - 10 % lower than the output tallies (7% uncertainty). The detailed dosimetry that was performed at the TNIF for the NCT will be described.« less

Dosimetry in Thermal Neutron Irradiation Facility at BMRR

NASA Astrophysics Data System (ADS)

Hu, J.-P.; Holden, N. E.; Reciniello, R. N.

2016-02-01

Radiation dosimetry for Neutron Capture Therapy (NCT) has been performed since 1959 at Thermal Neutron Irradiation Facility (TNIF) of the three-megawatt light-water cooled Brookhaven Medical Research Reactor (BMRR). In the early 1990s when more effective drug carriers were developed for NCT, in which the eye melanoma and brain tumors in rats were irradiated in situ, extensive clinical trials of small animals began using a focused thermal neutron beam. To improve the dosimetry at irradiation facility, a series of innovative designs and major modifications made to enhance the beam intensity and to ease the experimental sampling at BMRR were performed; including (1) in-core fuel addition to increase source strength and balance flux of neutrons towards two ports, (2) out of core moderator remodeling, done by replacing thicker D2O tanks at graphite-shutter interfacial areas, to expedite neutron thermalization, (3) beam shutter upgrade to reduce strayed neutrons and gamma dose, (4) beam collimator redesign to optimize the beam flux versus dose for animal treatment, (5) beam port shielding installation around the shutter opening area (lithium-6 enriched polyester-resin in boxes, attached with polyethylene plates) to reduce prompt gamma and fast neutron doses, (6) sample holder repositioning to optimize angle versus distance for a single organ or whole body irradiation, and (7) holder wall buildup with neutron reflector materials to increase dose and dose rate from scattered thermal neutrons. During the facility upgrade, reactor dosimetry was conducted using thermoluminescent dosimeters TLD for gamma dose estimate, using ion chambers to confirm fast neutron and gamma dose rate, and by the activation of gold-foils with and without cadmium-covers, for fast and thermal neutron flux determination. Based on the combined effect from the size and depth of tumor cells and the location and geometry of dosimeters, the measured flux from cadmium-difference method was 4-7% lower than the statistical mean derived from the Monte-Carlo modeling (5% uncertainty). The dose rate measured by ion chambers was 6-10% lower than the output tallies (7% uncertainty). The detailed dosimetry that was performed at the TNIF for the NCT will be described.

Rolling Shutter Effect aberration compensation in Digital Holographic Microscopy

NASA Astrophysics Data System (ADS)

Monaldi, Andrea C.; Romero, Gladis G.; Cabrera, Carlos M.; Blanc, Adriana V.; Alanís, Elvio E.

2016-05-01

Due to the sequential-readout nature of most CMOS sensors, each row of the sensor array is exposed at a different time, resulting in the so-called rolling shutter effect that induces geometric distortion to the image if the video camera or the object moves during image acquisition. Particularly in digital holograms recording, while the sensor captures progressively each row of the hologram, interferometric fringes can oscillate due to external vibrations and/or noises even when the object under study remains motionless. The sensor records each hologram row in different instants of these disturbances. As a final effect, phase information is corrupted, distorting the reconstructed holograms quality. We present a fast and simple method for compensating this effect based on image processing tools. The method is exemplified by holograms of microscopic biological static objects. Results encourage incorporating CMOS sensors over CCD in Digital Holographic Microscopy due to a better resolution and less expensive benefits.

A House Divided

ERIC Educational Resources Information Center

Carlson, Scott

2007-01-01

This article discusses Antioch College, a once-prominent countercultural institution that will be closed in 2008 due to serious financial problems. Antioch has been hemorrhaging money for years. Its Board of Trustees has decided to shutter the college by July 2008 and lay off most of its 160 staff and faculty members. Although the administration…

Pressure wave charged repetitively pulsed gas laser

DOEpatents

Kulkarny, Vijay A.

1982-01-01

A repetitively pulsed gas laser in which a system of mechanical shutters bracketing the laser cavity manipulate pressure waves resulting from residual energy in the cavity gas following a lasing event so as to draw fresh gas into the cavity and effectively pump spent gas in a dynamic closed loop.

On The Design and Implementation of a New Electric-Field Meter with Reciprocating Shutter and Field-Change-Antenna Option

NASA Astrophysics Data System (ADS)

Swenson, J.; Byerley, L. G.; Bogoev, I.; Hinckley, A.; Beasley, W. H.

2003-12-01

The atmospheric electric field is a unique indicator of locally disturbed weather, local thunderstorms and local atmospheric electrical hazards. Yet, surprisingly, routine observations of ambient electric field have never been included in the canonical suite of measured meteorological variables. This notable omission may be a result of the historically high costs to acquire, install, and maintain conventional electric-field mills. To reduce costs and overcome limitations of traditional field meters, Campbell Scientific, Inc. has developed an electric-field meter (patent pending) with a reciprocating shutter that eliminates the problem of making electrical contact with a rotating shaft. The reciprocating action is under microprocessor control, so the sample rate can be varied in response to measured conditions. Between samples of electric field, the shutter can even be left open indefinitely, allowing the instrument to function as a field-change antenna. Since the shutter is closed before and after each measurement in field-meter mode, it is relatively easy to account for drift and offsets automatically, so that measurements can be made even if the electrode insulator becomes degraded by conductive deposits of the types likely to be encountered in severe outdoor environments. Because the motor is energized for only a small fraction of each measurement cycle, average power consumption is exceptionally low, making the new field meter especially suitable for solar-powered applications such as automated remote meteorological stations. Some preliminary observations demonstrate the capabilities of the instrument.

Thermal Powered Reciprocating-Force Motor

NASA Technical Reports Server (NTRS)

Tatum, III, Paul F. (Inventor); McDow Elliott, Amelia (Inventor)

2015-01-01

A thermal-powered reciprocating-force motor includes a shutter switchable between a first position that passes solar energy and a second position that blocks solar energy. A shape memory alloy (SMA) actuator is coupled to the shutter to control switching thereof between the shutter's first and second position. The actuator is positioned with respect to the shutter such that (1) solar energy impinges on the SMA when the shutter is in its first position so that the SMA experiences contraction in length until the shutter is switched to its second position, and (2) solar energy is impeded from impingement on the SMA when the shutter is in its second position so that the SMA experiences extension in length. Elastic members coupled to the actuator apply a force to the SMA that aids in its extension in length until the shutter is switched to its first position.

EEG-based usability assessment of 3D shutter glasses

NASA Astrophysics Data System (ADS)

Wenzel, Markus A.; Schultze-Kraft, Rafael; Meinecke, Frank C.; Cardinaux, Fabien; Kemp, Thomas; Müller, Klaus-Robert; Curio, Gabriel; Blankertz, Benjamin

2016-02-01

Objective. Neurotechnology can contribute to the usability assessment of products by providing objective measures of neural workload and can uncover usability impediments that are not consciously perceived by test persons. In this study, the neural processing effort imposed on the viewer of 3D television by shutter glasses was quantified as a function of shutter frequency. In particular, we sought to determine the critical shutter frequency at which the ‘neural flicker’ vanishes, such that visual fatigue due to this additional neural effort can be prevented by increasing the frequency of the system. Approach. Twenty-three participants viewed an image through 3D shutter glasses, while multichannel electroencephalogram (EEG) was recorded. In total ten shutter frequencies were employed, selected individually for each participant to cover the range below, at and above the threshold of flicker perception. The source of the neural flicker correlate was extracted using independent component analysis and the flicker impact on the visual cortex was quantified by decoding the state of the shutter from the EEG. Main Result. Effects of the shutter glasses were traced in the EEG up to around 67 Hz—about 20 Hz over the flicker perception threshold—and vanished at the subsequent frequency level of 77 Hz. Significance. The impact of the shutter glasses on the visual cortex can be detected by neurotechnology even when a flicker is not reported by the participants. Potential impact. Increasing the shutter frequency from the usual 50 Hz or 60 Hz to 77 Hz reduces the risk of visual fatigue and thus improves shutter-glass-based 3D usability.

EEG-based usability assessment of 3D shutter glasses.

PubMed

Wenzel, Markus A; Schultze-Kraft, Rafael; Meinecke, Frank C; Fabien Cardinaux; Kemp, Thomas; Klaus-Robert Müller; Gabriel Curio; Benjamin Blankertz

2016-02-01

Neurotechnology can contribute to the usability assessment of products by providing objective measures of neural workload and can uncover usability impediments that are not consciously perceived by test persons. In this study, the neural processing effort imposed on the viewer of 3D television by shutter glasses was quantified as a function of shutter frequency. In particular, we sought to determine the critical shutter frequency at which the 'neural flicker' vanishes, such that visual fatigue due to this additional neural effort can be prevented by increasing the frequency of the system. Twenty-three participants viewed an image through 3D shutter glasses, while multichannel electroencephalogram (EEG) was recorded. In total ten shutter frequencies were employed, selected individually for each participant to cover the range below, at and above the threshold of flicker perception. The source of the neural flicker correlate was extracted using independent component analysis and the flicker impact on the visual cortex was quantified by decoding the state of the shutter from the EEG. Effects of the shutter glasses were traced in the EEG up to around 67 Hz-about 20 Hz over the flicker perception threshold-and vanished at the subsequent frequency level of 77 Hz. The impact of the shutter glasses on the visual cortex can be detected by neurotechnology even when a flicker is not reported by the participants. Potential impact. Increasing the shutter frequency from the usual 50 Hz or 60 Hz to 77 Hz reduces the risk of visual fatigue and thus improves shutter-glass-based 3D usability.

X-ray source safety shutter

DOEpatents

Robinet, McLouis

1977-05-31

An apparatus is provided for controlling the activation of a high energy radiation source having a shutter. The apparatus includes magnets and magnetically responsive switches appropriately placed and interconnected so that only with the shutter and other parts of the source in proper position can safe emission of radiation out an open shutter occur.

In-vacuum exposure shutter

DOEpatents

Johnson, Terry A.; Replogle, William C.; Bernardez, Luis J.

2004-06-01

An in-vacuum radiation exposure shutter device can be employed to regulate a large footprint light beam. The shutter device includes (a) a source of radiation that generates an energy beam; (2) a shutter that includes (i) a frame defining an aperture toward which the energy beam is directed and (ii) a plurality of blades that are secured to the frame; and (3) device that rotates the shutter to cause the plurality of blades to intercept or allow the energy beam to travel through the aperture. Each blade can have a substantially planar surface and the plurality of blades are secured to the frame such that the planar surfaces of the plurality of blades are substantially parallel to each other. The shutter device is particularly suited for operation in a vacuum environment and can achieve shuttering speeds from about 0.1 second to 0.001 second or faster.

Single-shot pressure-sensitive paint lifetime measurements on fast rotating blades using an optimized double-shutter technique

NASA Astrophysics Data System (ADS)

Weiss, Armin; Geisler, Reinhard; Schwermer, Till; Yorita, Daisuke; Henne, Ulrich; Klein, Christian; Raffel, Markus

2017-09-01

A pressure-sensitive paint (PSP) system is presented to measure global surface pressures on fast rotating blades. It is dedicated to solve the problem of blurred image data employing the single-shot lifetime method. The efficient blur reduction capability of an optimized double-shutter imaging technique is demonstrated omitting error-prone post-processing or laborious de-rotation setups. The system is applied on Mach-scaled DSA-9A helicopter blades in climb at various collective pitch settings and blade tip Mach and chord Reynolds numbers (M_{ {tip}} = 0.29-0.57; Re_{ {tip}} = 4.63-9.26 × 10^5). Temperature effects in the PSP are corrected by a theoretical approximation validated against measured temperatures using temperature-sensitive paint (TSP) on a separate blade. Ensemble-averaged PSP results are comparable to pressure-tap data on the same blade to within 250 Pa. Resulting pressure maps on the blade suction side reveal spatially high resolved flow features such as the leading edge suction peak, footprints of blade-tip vortices and evidence of laminar-turbulent boundary-layer (BL) transition. The findings are validated by a separately conducted BL transition measurement by means of TSP and numerical simulations using a 2D coupled Euler/boundary-layer code. Moreover, the principal ability of the single-shot technique to capture unsteady flow phenomena is stressed revealing three-dimensional pressure fluctuations at stall.

DLP™-based dichoptic vision test system

NASA Astrophysics Data System (ADS)

Woods, Russell L.; Apfelbaum, Henry L.; Peli, Eli

2010-01-01

It can be useful to present a different image to each of the two eyes while they cooperatively view the world. Such dichoptic presentation can occur in investigations of stereoscopic and binocular vision (e.g., strabismus, amblyopia) and vision rehabilitation in clinical and research settings. Various techniques have been used to construct dichoptic displays. The most common and most flexible modern technique uses liquid-crystal (LC) shutters. When used in combination with cathode ray tube (CRT) displays, there is often leakage of light from the image intended for one eye into the view of the other eye. Such interocular crosstalk is 14% even in our state of the art CRT-based dichoptic system. While such crosstalk may have minimal impact on stereo movie or video game experiences, it can defeat clinical and research investigations. We use micromirror digital light processing (DLP™) technology to create a novel dichoptic visual display system with substantially lower interocular crosstalk (0.3% remaining crosstalk comes from the LC shutters). The DLP system normally uses a color wheel to display color images. Our approach is to disable the color wheel, synchronize the display directly to the computer's sync signal, allocate each of the three (former) color presentations to one or both eyes, and open and close the LC shutters in synchrony with those color events.

Programmable 2-D Addressable Cryogenic Aperture Masks

NASA Technical Reports Server (NTRS)

Kutyrev, A. S.; Moseley, S. H.; Jhabvala, M.; Li, M.; Schwinger, D. S.; Silverberg, R. F.; Wesenberg, R. P.

2004-01-01

We are developing a two-dimensional array of square microshutters (programmable aperture mask) for a multi-object spectrometer for the James Webb Space Telescope (JWST). This device will provide random access selection of the areas in the field to be studied. The device is in essence a close packed array of square slits, each of which can be opened independently to select areas of the sky for detailed study.The device is produced using a 100-micron thick silicon wafer as a substrate with 0.5-micron thick silicon nitride shutters on top of it. Silicon nitride has been selected as the blade and flexure material because its stiffness allows thinner and lighter structures than single crystal Si, the chief alternative, and because of its ease of manufacture. The 100 micron silicon wafer is backetched in a high aspect ratio Deep Reactive Ion Etching (Deep RIE) to leave only a support grid for the shutters and the address electronics. The shutter actuation is done magnetically whereas addressing is electrostatic. 128x128 format microshutter arrays have been produced. Their operation has been demostarted on 32x32 subarrays. Good reliability of the fabrication process and good quality of the microshutters has been achieved. The mechanical behavior and optical performance of the fabricated arrays at cryogenic temperature are being studied.

Photogrammetric Accuracy and Modeling of Rolling Shutter Cameras

NASA Astrophysics Data System (ADS)

Vautherin, Jonas; Rutishauser, Simon; Schneider-Zapp, Klaus; Choi, Hon Fai; Chovancova, Venera; Glass, Alexis; Strecha, Christoph

2016-06-01

Unmanned aerial vehicles (UAVs) are becoming increasingly popular in professional mapping for stockpile analysis, construction site monitoring, and many other applications. Due to their robustness and competitive pricing, consumer UAVs are used more and more for these applications, but they are usually equipped with rolling shutter cameras. This is a significant obstacle when it comes to extracting high accuracy measurements using available photogrammetry software packages. In this paper, we evaluate the impact of the rolling shutter cameras of typical consumer UAVs on the accuracy of a 3D reconstruction. Hereto, we use a beta-version of the Pix4Dmapper 2.1 software to compare traditional (non rolling shutter) camera models against a newly implemented rolling shutter model with respect to both the accuracy of geo-referenced validation points and to the quality of the motion estimation. Multiple datasets have been acquired using popular quadrocopters (DJI Phantom 2 Vision+, DJI Inspire 1 and 3DR Solo) following a grid flight plan. For comparison, we acquired a dataset using a professional mapping drone (senseFly eBee) equipped with a global shutter camera. The bundle block adjustment of each dataset shows a significant accuracy improvement on validation ground control points when applying the new rolling shutter camera model for flights at higher speed (8m=s). Competitive accuracies can be obtained by using the rolling shutter model, although global shutter cameras are still superior. Furthermore, we are able to show that the speed of the drone (and its direction) can be solely estimated from the rolling shutter effect of the camera.

Double-layered liquid crystal light shutter for control of absorption and scattering of the light incident to a transparent display device

NASA Astrophysics Data System (ADS)

Huh, Jae-Won; Yu, Byeong-Hun; Shin, Dong-Myung; Yoon, Tae-Hoon

2015-03-01

Recently, a transparent display has got much attention as one of the next generation display devices. Especially, active studies on a transparent display using organic light-emitting diodes (OLEDs) are in progress. However, since it is not possible to obtain black color using a transparent OLED, it suffers from poor visibility. This inevitable problem can be solved by using a light shutter. Light shutter technology can be divided into two types; light absorption and scattering. However, a light shutter based on light absorption cannot block the background image perfectly and a light shutter based on light scattering cannot provide black color. In this work we demonstrate a light shutter using two liquid crystal (LC) layers, a light absorption layer and a light scattering layer. To realize a light absorption layer and a light scattering layer, we use the planar state of a dye-doped chiral nematic LC (CNLC) cell and the focal-conic state of a long-pitch CNLC cell, respectively. The proposed light shutter device can block the background image perfectly and show black color. We expect that the proposed light shutter can increase the visibility of a transparent display.

Collateral Damage

DTIC Science & Technology

1978-10-01

stated, they are, in reality , indexed to a single aspect of the weapon phenomena, e.g., damage levels for airblast-sensitive objects are indexed to...of Burst Propagation Related Airblast Representation Target Altitude Wheather (snow/rain) Terrain Temperature Air Pressure Around Structures 1. d) 3-38...with opaque material. Simply closing a shutter can be quite effective in virtually eliminating all possibility of interior fire starts from a single

Dips in Enrollment Posing Challenges for Urban Districts

ERIC Educational Resources Information Center

Gehring, John

2005-01-01

Across the U.S., urban school districts are losing students and shuttering schools. In Detroit, some 35,000 students have left the city schools in less than a decade, and the city will close 34 schools and reassign more than 10,000 students in 2006. However, the trend is not limited to Rust Belt cities like Detroit, although their problems tend to…

Advanced Shutter Control for a Molecular Beam Epitaxy Reactor

DTIC Science & Technology

An open-source hardware and software-based shutter controller solution was developed that communicates over Ethernet with our original equipment...manufacturer (OEM) molecular beam epitaxy (MBE) reactor control software. An Arduino Mega microcontroller is the used for the brain of the shutter... controller , while a custom-designed circuit board distributes 24-V power to each of the 16 shutter solenoids available on the MBE. Using Ethernet

Note: Reliable low-vibration piezo-mechanical shutter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Michael, E-mail: mibauer@physik.uni-kl.de; Franzreb, Philipp Pierre; Widera, Artur

2014-09-15

We present a mechanical shutter based on a bending piezo-actuator. The shutter features an active aperture of about 2 mm, allowing for full extinction and lossless transmission of a beam. Acoustic noise and mechanical vibrations produced are very low and the shutter is outstandingly long-lived; a test device has undergone 20 × 10{sup 6} cycles without breaking. A reflector makes the shutter capable of reliably interrupting a beam with at least 2 W of cw power at 780 nm. The shutter is well suited to create pulses as short as 16 ms, while pulse lengths down to 1 ms aremore » possible. The rise and fall times are approximately 120 µs, with a delay of 2 ms. Jitter stays below 10 µs, while long-term drifts stay well below 500 µs.« less

Application of PLZT electro-optical shutter to diaphragm of visible and mid-infrared cameras

NASA Astrophysics Data System (ADS)

Fukuyama, Yoshiyuki; Nishioka, Shunji; Chonan, Takao; Sugii, Masakatsu; Shirahata, Hiromichi

1997-04-01

Pb0.9La0.09(Zr0.65,Ti0.35)0.9775O3 9/65/35) commonly used as an electro-optical shutter exhibits large phase retardation with low applied voltage. This shutter features as follows; (1) high shutter speed, (2) wide optical transmittance, and (3) high optical density in 'OFF'-state. If the shutter is applied to a diaphragm of video-camera, it could protect its sensor from intense lights. We have tested the basic characteristics of the PLZT electro-optical shutter and resolved power of imaging. The ratio of optical transmittance at 'ON' and 'OFF'-states was 1.1 X 103. The response time of the PLZT shutter from 'ON'-state to 'OFF'-state was 10 micro second. MTF reduction when putting the PLZT shutter in from of the visible video- camera lens has been observed only with 12 percent at a spatial frequency of 38 cycles/mm which are sensor resolution of the video-camera. Moreover, we took the visible image of the Si-CCD video-camera. The He-Ne laser ghost image was observed at 'ON'-state. On the contrary, the ghost image was totally shut out at 'OFF'-state. From these teste, it has been found that the PLZT shutter is useful for the diaphragm of the visible video-camera. The measured optical transmittance of PLZT wafer with no antireflection coating was 78 percent over the range from 2 to 6 microns.

Advanced electro-mechanical micro-shutters for thermal infrared night vision imaging and targeting systems

NASA Astrophysics Data System (ADS)

Durfee, David; Johnson, Walter; McLeod, Scott

2007-04-01

Un-cooled microbolometer sensors used in modern infrared night vision systems such as driver vehicle enhancement (DVE) or thermal weapons sights (TWS) require a mechanical shutter. Although much consideration is given to the performance requirements of the sensor, supporting electronic components and imaging optics, the shutter technology required to survive in combat is typically the last consideration in the system design. Electro-mechanical shutters used in military IR applications must be reliable in temperature extremes from a low temperature of -40°C to a high temperature of +70°C. They must be extremely light weight while having the ability to withstand the high vibration and shock forces associated with systems mounted in military combat vehicles, weapon telescopic sights, or downed unmanned aerial vehicles (UAV). Electro-mechanical shutters must have minimal power consumption and contain circuitry integrated into the shutter to manage battery power while simultaneously adapting to changes in electrical component operating parameters caused by extreme temperature variations. The technology required to produce a miniature electro-mechanical shutter capable of fitting into a rifle scope with these capabilities requires innovations in mechanical design, material science, and electronics. This paper describes a new, miniature electro-mechanical shutter technology with integrated power management electronics designed for extreme service infra-red night vision systems.

Some Aspects on the Mechanical Analysis of Micro-Shutters

NASA Technical Reports Server (NTRS)

Fettig, Rainer K.; Kuhn, Jonathan L.; Moseley, S. Harvey; Kutyrev, Alexander S.; Orloff, Jon; Lu, Shude

1999-01-01

An array of individually addressable micro-shutters is being designed for spectroscopic applications. Details of the design are presented in a companion paper. The mechanical design of a single shutter element has been completed. This design consists of a shutter blade suspended on a torsion beam manufactured out of single crystal silicon membranes. During operation the shutter blade will be rotated by 90 degrees out of the array plane. Thus, the stability and durability of the beams are crucial for the reliability of the devices. Structures were fabricated using focused ion beam milling in a FEI 620 dual beam machine, and subsequent testing was completed using the same platform. This allowed for short turn around times. We performed torsion and bending experiments to determine key characteristics of the membrane material. Results of measurements on prototype shutters were compared with the predictions of the numerical models. The data from these focused studies were used in conjunction with experiments and numerical models of shutter prototypes to optimize the design. In this work, we present the results of the material studies, and assess the mechanical performance of the resulting design.

Focal Plane Array Shutter Mechanism of the JWST NIRSpec Detector System

NASA Technical Reports Server (NTRS)

Hale, Kathleen; Sharma, Rajeev

2006-01-01

This viewgraph presentation reviews the requirements, chamber location, shutter system design, stepper motor specifications, dry lubrication, control system, the environmental cryogenic function testing and the test results of the Focal Plane Array Shutter mechanism for the James Webb Space Telescope Near Infrared Spectrum Detector system. Included are design views of the location for the Shutter Mechanism, lubricant (lubricated with Molybdenum Di Sulfide) thickness, and information gained from the cryogenic testing.

Motion-Blur-Free High-Speed Video Shooting Using a Resonant Mirror

PubMed Central

Inoue, Michiaki; Gu, Qingyi; Takaki, Takeshi; Ishii, Idaku; Tajima, Kenji

2017-01-01

This study proposes a novel concept of actuator-driven frame-by-frame intermittent tracking for motion-blur-free video shooting of fast-moving objects. The camera frame and shutter timings are controlled for motion blur reduction in synchronization with a free-vibration-type actuator vibrating with a large amplitude at hundreds of hertz so that motion blur can be significantly reduced in free-viewpoint high-frame-rate video shooting for fast-moving objects by deriving the maximum performance of the actuator. We develop a prototype of a motion-blur-free video shooting system by implementing our frame-by-frame intermittent tracking algorithm on a high-speed video camera system with a resonant mirror vibrating at 750 Hz. It can capture 1024 × 1024 images of fast-moving objects at 750 fps with an exposure time of 0.33 ms without motion blur. Several experimental results for fast-moving objects verify that our proposed method can reduce image degradation from motion blur without decreasing the camera exposure time. PMID:29109385

High-speed electromechanical shutter for imaging spectrographs

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet (Inventor)

2005-01-01

The present invention presents a high-speed electromechanical shutter which has at least two rotary beam choppers that are synchronized using a phase-locked loop electronic control to reduce the duty cycle. These choppers have blade means that can comprise discs or drums, each having about 60 (+/-15) slots which are from about 0.3 to about 0.8 mm wide and about 5 to about 20 mm long (radially) which are evenly distributed through out 360?, and a third rotary chopper which is optically aligned has a small number of slots, such as for example, 1 to 10 slots which are about 1 to about 2 mm wide and about 5 to about 20 mm long (radially). Further the blade means include phase slots that allow the blade means to be phase locked using a closed loop control circuit. In addition, in a preferred embodiment, the system also has a leaf shutter. Thus the invention preferably achieves a gate width of less than about 100 microseconds, using motors that operate at 3000 to 10,000 rpm, and with a phase jitter of less than about 1.5 microseconds, and further using an aperture with more than about 75% optical transmission with a clear aperture of about 0.8 mm?10 mm. The system can be synchronized to external sources at 0 6 kHz lasers, data acquisition systems, and cameras.

Method to control deposition rate instabilities—High power impulse magnetron sputtering deposition of TiO{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kossoy, Anna, E-mail: annaeden@hi.is, E-mail: anna.kossoy@gmail.com; Magnusson, Rögnvaldur L.; Tryggvason, Tryggvi K.

2015-03-15

The authors describe how changes in shutter state (open/closed) affect sputter plasma conditions and stability of the deposition rate of Ti and TiO{sub 2} films. The films were grown by high power impulse magnetron sputtering in pure Ar and in Ar/O{sub 2} mixture from a metallic Ti target. The shutter state was found to have an effect on the pulse waveform for both pure Ar and reactive sputtering of Ti also affecting stability of TiO{sub 2} deposition rate. When the shutter opened, the shape of pulse current changed from rectangular to peak-plateau and pulse energy decreased. The authors attribute itmore » to the change in plasma impedance and gas rarefaction originating in geometry change in front of the magnetron. TiO{sub 2} deposition rate was initially found to be high, 1.45 Å/s, and then dropped by ∼40% during the first 5 min, while for Ti the change was less obvious. Instability of deposition rate poses significant challenge for growing multilayer heterostructures. In this work, the authors suggest a way to overcome this by monitoring the integrated average energy involved in the deposition process. It is possible to calibrate and control the film thickness by monitoring the integrated pulse energy and end growth when desired integrated pulse energy level has been reached.« less

Automatic lightning detection and photographic system

NASA Technical Reports Server (NTRS)

Wojtasinski, R. J.; Holley, L. D.; Gray, J. L.; Hoover, R. B. (Inventor)

1972-01-01

A system is presented for monitoring and recording lightning strokes within a predetermined area with a camera having an electrically operated shutter with means for advancing the film in the camera after activating the shutter. The system includes an antenna for sensing lightning strikes which, in turn, generates a signal that is fed to an electronic circuit which generates signals for operating the shutter of the camera. Circuitry is provided for preventing activation of the shutter as the film in the camera is being advanced.

Advances in shutter drive technology to enhance man-portable infrared cameras

NASA Astrophysics Data System (ADS)

Durfee, David

2012-06-01

With an emphasis on highest reliability, infrared (IR) imagers have traditionally used simplest-possible shutters and field-proven technology. Most commonly, single-step rotary or linear magnetic actuators have been used with good success. However, several newer shutter drive technologies offer benefits in size and power reduction, enabling man-portable imagers that are more compact, lighter, and more durable. This paper will discuss improvements in shutter and shutter drive technology, which enable smaller and more power-efficient imagers. Topics will transition from single-step magnetic actuators to multi-stepping magnetic drives, latching vs. balanced systems for blade position shock-resistance, motor and geared motor drives, and associated stepper driver electronics. It will highlight performance tradeoffs pertinent to man-portable military systems.

Motion Sickness Treatment Apparatus and Method

NASA Technical Reports Server (NTRS)

Reschke, Millard F. (Inventor); Somers, Jeffrey T. (Inventor); Ford, George A. (Inventor)

2005-01-01

Methods and apparatus are disclosed for treating motion sickness. In a preferred embodiment a method of the invention comprises operating eyewear having shutter lenses to open said shutter lenses at a selected operating frequency ranging from within about 3 Hz to about 50 Hz. The shutter lenses are opened for a short duration at the selected operating frequency wherein the duration is selected to prevent retinal slip. The shutter lenses may be operated at a relatively slow frequency of about 4 Hz when the user is in passive activity such as riding in a boat or car or in limited motion situations in a spacecraft. The shutter lenses may be operated at faster frequencies related to motion of the user's head when the user is active.

New Developments of Broadband Cavity Enhanced Spectroscopic Techniques

NASA Astrophysics Data System (ADS)

Walsh, A.; Zhao, D.; Linnartz, H.; Ubachs, W.

2013-06-01

In recent years, cavity enhanced spectroscopic techniques, such as cavity ring-down spectroscopy (CRDS), cavity enhanced absorption spectroscopy (CEAS), and broadband cavity enhanced absorption spectroscopy (BBCEAS), have been widely employed as ultra-sensitive methods for the measurement of weak absorptions and in the real-time detection of trace species. In this contribution, we introduce two new cavity enhanced spectroscopic concepts: a) Optomechanical shutter modulated BBCEAS, a variant of BBCEAS capable of measuring optical absorption in pulsed systems with typically low duty cycles. In conventional BBCEAS applications, the latter substantially reduces the signal-to-noise ratio (S/N), consequently also reducing the detection sensitivity. To overcome this, we incorporate a fast optomechanical shutter as a time gate, modulating the detection scheme of BBCEAS and increasing the effective duty cycle reaches a value close to unity. This extends the applications of BBCEAS into pulsed samples and also in time-resolved studies. b) Cavity enhanced self-absorption spectroscopy (CESAS), a new spectroscopic concept capable of studying light emitting matter (plasma, flames, combustion samples) simultaneously in absorption and emission. In CESAS, a sample (plasma, flame or combustion source) is located in an optically stable cavity consisting of two high reflectivity mirrors, and here it acts both as light source and absorbing medium. A high detection sensitivity of weak absorption is reached without the need of an external light source, such as a laser or broadband lamp. The performance is illustrated by the first CESAS result on a supersonically expanding hydrocarbon plasma. We expect CESAS to become a generally applicable analytical tool for real time and in situ diagnostics. A. Walsh, D. Zhao, W. Ubachs, H. Linnartz, J. Phys. Chem. A, {dx.doi.org/10.1021/jp310392n}, in press, 2013. A. Walsh, D. Zhao, H. Linnartz Rev. Sci. Instrum. {84}(2), 021608 2013. A. Walsh, D. Zhao, H. Linnartz Appl. Phys. Lett. {101}(9), 091111 2012.

Improved Space Object Orbit Determination Using CMOS Detectors

NASA Astrophysics Data System (ADS)

Schildknecht, T.; Peltonen, J.; Sännti, T.; Silha, J.; Flohrer, T.

2014-09-01

CMOS-sensors, or in general Active Pixel Sensors (APS), are rapidly replacing CCDs in the consumer camera market. Due to significant technological advances during the past years these devices start to compete with CCDs also for demanding scientific imaging applications, in particular in the astronomy community. CMOS detectors offer a series of inherent advantages compared to CCDs, due to the structure of their basic pixel cells, which each contains their own amplifier and readout electronics. The most prominent advantages for space object observations are the extremely fast and flexible readout capabilities, feasibility for electronic shuttering and precise epoch registration, and the potential to perform image processing operations on-chip and in real-time. The major challenges and design drivers for ground-based and space-based optical observation strategies have been analyzed. CMOS detector characteristics were critically evaluated and compared with the established CCD technology, especially with respect to the above mentioned observations. Similarly, the desirable on-chip processing functionalities which would further enhance the object detection and image segmentation were identified. Finally, we simulated several observation scenarios for ground- and space-based sensor by assuming different observation and sensor properties. We will introduce the analyzed end-to-end simulations of the ground- and space-based strategies in order to investigate the orbit determination accuracy and its sensitivity which may result from different values for the frame-rate, pixel scale, astrometric and epoch registration accuracies. Two cases were simulated, a survey using a ground-based sensor to observe objects in LEO for surveillance applications, and a statistical survey with a space-based sensor orbiting in LEO observing small-size debris in LEO. The ground-based LEO survey uses a dynamical fence close to the Earth shadow a few hours after sunset. For the space-based scenario a sensor in a sun-synchronous LEO orbit, always pointing in the anti-sun direction to achieve optimum illumination conditions for small LEO debris, was simulated. For the space-based scenario the simulations showed a 20 130 % improvement of the accuracy of all orbital parameters when varying the frame rate from 1/3 fps, which is the fastest rate for a typical CCD detector, to 50 fps, which represents the highest rate of scientific CMOS cameras. Changing the epoch registration accuracy from a typical 20.0 ms for a mechanical shutter to 0.025 ms, the theoretical value for the electronic shutter of a CMOS camera, improved the orbit accuracy by 4 to 190 %. The ground-based scenario also benefit from the specific CMOS characteristics, but to a lesser extent.

Demonstrations with a Liquid Crystal Shutter

ERIC Educational Resources Information Center

Kraftmakher, Yaakov

2012-01-01

The experiments presented show the response of a liquid crystal shutter to applied electric voltages and the delay of the operations. Both properties are important for liquid crystal displays of computers and television sets. Two characteristics of the shutter are determined: (i) the optical transmittance versus applied voltage of various…

Use of color-coded sleeve shutters accelerates oscillograph channel selection

NASA Technical Reports Server (NTRS)

Bouchlas, T.; Bowden, F. W.

1967-01-01

Sleeve-type shutters mechanically adjust individual galvanometer light beams onto or away from selected channels on oscillograph papers. In complex test setups, the sleeve-type shutters are color coded to separately identify each oscillograph channel. This technique could be used on any equipment using tubular galvanometer light sources.

Variable orifice using an iris shutter

DOEpatents

Beeman, Raymond; Brajkovich, Steven J.

1978-01-01

A variable orifice forming mechanism utilizing an iris shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow.

Solar shutter arrangement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulkerson, P.L.

1988-02-02

In a structure having a roof with a skylight including a glass panel which transmits solar energy, a shutter arrangement supported on the roof is described comprising an insulative flat one-piece solid shutter in the form of a panel selectively and linearly slidable on tracks which conceal the side edges thereof from a position blocking transmittal of solar energy through the glass panel of the skylight into an area within the structure to a position permitting transmittal of solar energy through the glass panel of the skylight into the area within the structure. The skylight presents a space between themore » glass panel and the selectively and linearly slidable insulative flat one-piece solid shutter, where the latter serves as the selective inner wall of the space contiguous with the area within the structure and the glass panel serves as the fixed outer wall of the space, where temperature responsive means is disposed within the space and in direct engagement with the inner surface of the glass panel, where the temperature responsive means is a black thermocouple operating a motor in a driving relationship with the insulative flat one-piece solid shutter. The insulative flat one-piece solid shutter is supported by a cable secured to a rotatable shaft controlled by the motor, where bi-directional movement of the rotatable shaft achieves raising and lowering of the insulative flat one-piece solid shutter to each of the solar energy blocking and transmittal positions, and where the insulative flat one-piece solid shutter includes a reflective surface facing the skylight and a decorative surface facing the area within the structure.« less

The optimal code searching method with an improved criterion of coded exposure for remote sensing image restoration

NASA Astrophysics Data System (ADS)

He, Lirong; Cui, Guangmang; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

2015-03-01

Coded exposure photography makes the motion de-blurring a well-posed problem. The integration pattern of light is modulated using the method of coded exposure by opening and closing the shutter within the exposure time, changing the traditional shutter frequency spectrum into a wider frequency band in order to preserve more image information in frequency domain. The searching method of optimal code is significant for coded exposure. In this paper, an improved criterion of the optimal code searching is proposed by analyzing relationship between code length and the number of ones in the code, considering the noise effect on code selection with the affine noise model. Then the optimal code is obtained utilizing the method of genetic searching algorithm based on the proposed selection criterion. Experimental results show that the time consuming of searching optimal code decreases with the presented method. The restoration image is obtained with better subjective experience and superior objective evaluation values.

Functional morphology of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae), a bacterially luminous coral reef fish.

PubMed

Dunlap, Paul V; Nakamura, Masaru

2011-08-01

Previous studies of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae) identified a ventral light organ, reflector, lens, duct, and a ventral diffuser extending from the throat to the caudal peduncle. The control and function of luminescence in this and other species of Siphamia, however, have not been defined. Morphological examination of fresh and preserved specimens identified additional components of the luminescence system involved in control and ventral emission of luminescence, including a retractable shutter over the ventral face of the light organ, contiguity of the ventral diffuser from the caudal peduncle to near the chin, and transparency of the bones and other tissues of the lower jaw. The shutter halves retract laterally, allowing the ventral release of light, and relax medially, blocking ventral light emission; topical application of norepinephrine to the exposed light organ resulted in retraction of the shutter halves, which suggests that operation of the shutter is under neuromuscular control. The extension of the diffuser to near the chin and transparency of the lower jaw allow a uniform emission of luminescence over the entire ventrum of the fish. The live aquarium-held fish were found to readily and consistently display ventral luminescence. At twilight, the fish left the protective association with their longspine sea urchin, Diadema setosum, and began to emit ventral luminescence and to feed on zooplankton. Ventral luminescence illuminated a zone below and around the fish, which typically swam close to the substrate. Shortly after complete darkness, the fish stopped feeding and emitting luminescence. These observations suggest that S. versicolor uses ventral luminescence to attract and feed on zooplankton from the reef benthos at twilight. Ventral luminescence may allow S. versicolor to exploit for feeding the gap at twilight in the presence of potential predators as the reef transitions from diurnally active to nocturnally active organisms. Copyright © 2011 Wiley-Liss, Inc.

Apparatus for insulating windows and the like

DOEpatents

Mitchell, R.A.

1984-06-19

Apparatus for insulating window openings through walls and the like includes a thermal shutter, a rail for mounting the shutter adjacent to the window opening and a coupling for connecting the shutter to the rail. The thermal shutter includes an insulated panel adhered to frame members which surround the periphery of the panel. The frame members include a hard portion for providing the frame and a soft portion for providing a seal with that portion of the wall adjacent to the periphery of the opening. The coupling means is preferably integral with the attachment rail. According to a preferred embodiment, the coupling means includes a continuous hinge of reduced thickness. The thermal shutter can be permanently attached, hinged, bi-folded, or sliding with respect to the window and wall. A distribution method is to market the apparatus in kit'' form. 11 figs.

Development of a drive system for a sequential space camera

NASA Technical Reports Server (NTRS)

Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

1976-01-01

Breadboard models of single and dual motor drives for the shutter, claw and magazine of a space camera system were designed and tested. The single motor technique utilizes a single electronically commutated motor to drive the claw and shutter without resorting to a solenoid actuated clutch for pulse operation. Shutter speed is established by a combination of the cinemode speed and the opening of the conventional DAC two piece shutter. Pulse mode operation is obtained by applying power at a fixed clock rate and removing power at an appropriate point in the mechanical cycle such that the motor comes to rest by system friction. The dual motor approach utilizes a stepper motor to drive the shutter and an electronically commutated dc motor to drive the claw and magazine functions. The motors are synchronized electronically.

Apparatus for insulating windows and the like

DOEpatents

Mitchell, Robert A.

1984-01-01

Apparatus for insulating window openings through walls and the like includes a thermal shutter, a rail for mounting the shutter adjacent to the window opening and a coupling for connecting the shutter to the rail. The thermal shutter includes an insulated panel adhered to frame members which surround the periphery of the panel. The frame members include a hard portion for providing the frame and a soft portion for providing a seal with that portion of the wall adjacent to the periphery of the opening. The coupling means is preferably integral with the attachment rail. According to a preferred embodiment, the coupling means includes a continuous hinge of reduced thickness. The thermal shutter can be permanently attached, hinged, bi-folded, or sliding with respect to the window and wall. A distribution method is to market the apparatus in "kit" form.

Smart window using a thermally and optically switchable liquid crystal cell

NASA Astrophysics Data System (ADS)

Oh, Seung-Won; Kim, Sang-Hyeok; Baek, Jong-Min; Yoon, Tae-Hoon

2018-02-01

Light shutter technologies that can control optical transparency have been studied extensively for developing curtain-free smart windows. We introduce thermally and optically switchable light shutters using LCs doped with push-pull azobenzene, which is known to speed up thermal relaxation. The liquid crystal light shutter can be switched between translucent and transparent states or transparent and opaque states by phase transition through changing temperature or photo-isomerization of doped azobenzene. The liquid crystal light shutter can be used for privacy windows with an initial translucent state or energy-saving windows with an initial transparent state.

IMPROVEMENTS IN RADIATION SHUTTERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-07-12

An apparatus for the protection of eyesight from the radiated energy released from a thermonuclear explosion is described. The apparatus consists of a shutter which is opaque to the radiation, an electrically ignitible detonator for blowing the shutter across the path of the radiation, and a phototransistor for igniting the detonator when the radiated energy exceeds a level which is injurious to the eyesight. There may be a second detonator for blowing the shutter away after the explosion has subsided. The second detonator is manually operated. Diagrams show the apparatus attached to a soldier's helmet and a turret. (N.W.R.)

Optical bi-stable shutter development/improvement

NASA Astrophysics Data System (ADS)

Lizon, J. L.; Haddad, N.; Castillo, R.

2012-09-01

Two of the VLT instruments (Giraffe and VIMOS) are using the large magnetic E/150 from Prontor (with an aperture diameter of 150 mm). As we were facing an unacceptable number of failures with this component some improvement plan was discussed already in 2004. The final decision for starting this program was conditioned by the decision from the constructor to stop the production. The opportunity was taken to improve the design building a fully bi-stable mechanism in order to reduce the thermal dissipation. The project was developed in collaboration between the two main ESO sites doing the best use of the manpower and of the technical capability available at the two centers. The project took advantage of the laser Mask Manufacturing Unit and the invar sheets used to prepare the VIMOS MOS mask to fabricate the shutter petals. Our paper describes the development including the intensive and long optimization period. To conclude this optimization we proceed with a long life test on two units. These units have demonstrate a very high level of reliability (up to 100 000 cycles without failure which can be estimated to an equivalent 6 years of operation of the instrument) A new bi-stable shutter driver and controller have also been developed. Some of the highlights of this unit are the fully configurable coil driving parameters, usage of braking strategy to dump mechanical vibration and reduce mechanical wearing, configurable usage of OPEN and CLOSE sensors, non volatile storage of parameters, user friendly front panel interface.

Sunlight-switchable light shutter fabricated using liquid crystals doped with push-pull azobenzene.

PubMed

Oh, Seung-Won; Baek, Jong-Min; Yoon, Tae-Hoon

2016-11-14

We propose a sunlight-switchable light shutter using liquid crystal/polymer composite doped with push-pull azobenzene. The proposed light shutter is switchable between the translucent and transparent states by application of an electric field or by UV irradiation. Switching by UV irradiation is based on the change of the liquid crystal (LC) clearing point by the photo-isomerization effect of push-pull azobenzene. Under sunlight, the light shutter can be switched from the translucent to the transparent state by the nematic-isotropic phase transition of the LC domains triggered by trans-cis photo-isomerization of the push-pull azobenzene molecules. When the amount of sunlight is low because of cloud cover or when there is no sunlight at sunset, the light shutter rapidly relaxes from its transparent state back to its initial translucent state by the isotropic-nematic phase transition induced by cis-trans back-isomerization of the push-pull azobenzene molecules.

Development of Gentle Slope Light Guide Structure in a 3.4 μm Pixel Pitch Global Shutter CMOS Image Sensor with Multiple Accumulation Shutter Technology.

PubMed

Sekine, Hiroshi; Kobayashi, Masahiro; Onuki, Yusuke; Kawabata, Kazunari; Tsuboi, Toshiki; Matsuno, Yasushi; Takahashi, Hidekazu; Inoue, Shunsuke; Ichikawa, Takeshi

2017-12-09

CMOS image sensors (CISs) with global shutter (GS) function are strongly required in order to avoid image degradation. However, CISs with GS function have generally been inferior to the rolling shutter (RS) CIS in performance, because they have more components. This problem is remarkable in small pixel pitch. The newly developed 3.4 µm pitch GS CIS solves this problem by using multiple accumulation shutter technology and the gentle slope light guide structure. As a result, the developed GS pixel achieves 1.8 e - temporal noise and 16,200 e - full well capacity with charge domain memory in 120 fps operation. The sensitivity and parasitic light sensitivity are 28,000 e - /lx·s and -89 dB, respectively. Moreover, the incident light angle dependence of sensitivity and parasitic light sensitivity are improved by the gentle slope light guide structure.

Multichannel optical sensing device

DOEpatents

Selkowitz, S.E.

1985-08-16

A multichannel optical sensing device is disclosed, for measuring the outdoor sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optical elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

Multichannel optical sensing device

DOEpatents

Selkowitz, Stephen E.

1990-01-01

A multichannel optical sensing device is disclosed, for measuring the outr sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optic elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XIII, I--MAINTAINING THE FUEL SYSTEM (PART III), CUMMINS DIESEL ENGINES, II--RADIATOR SHUTTER SYSTEM.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE CONSTRUCTION, OPERATION, AND MAINTENANCE OF THE DIESEL ENGINE FUEL AND RADIATOR SHUTTER SYSTEMS. TOPICS ARE (1) MORE ABOUT THE CUMMINS FUEL SYSTEM, (2) CALIBRATING THE PT FUEL PUMP, (3) CALIBRATING THE FUEL INJECTORS, (4) UNDERSTANDING THE SHUTTER SYSTEM, (5) THE…

Control and automation of the Pegasus multi-point Thomson scattering system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodner, G. M., E-mail: gbodner@wisc.edu; Bongard, M. W.; Fonck, R. J.

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. Additionally, the system has been upgraded with a set of fast (∼1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

Control and automation of the Pegasus multi-point Thomson scattering system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodner, Grant M.; Bongard, Michael W.; Fonck, Raymond J.

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. In addition, the system has been upgraded with a set of fast (~1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

Control and automation of the Pegasus multi-point Thomson scattering system

DOE PAGES

Bodner, Grant M.; Bongard, Michael W.; Fonck, Raymond J.; ...

2016-08-12

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. In addition, the system has been upgraded with a set of fast (~1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

Subpicosecond pulses from a neodymium-glass laser with a solid-liquid phototropic shutter

NASA Astrophysics Data System (ADS)

Altshuler, G. B.; Dulneva, E. G.; Karasev, V. B.; Okishev, A. V.; Telegin, L. S.

1985-02-01

Subpicosecond, spectrally limited pulses were generated in a mode-locked silicate-Nd-glass laser by means of a phototropic shutter. The shutter featured molecules of an organic dye added to a matrix composed of an isobutyl alcohol-filled quartz micropore glass plate. A coating on the inner surface of one of the cell windows was 0.99 reflective at the lasing wavelength. Single pulses with 0.5-1 psec length were generated, validating the use of a solid-liquid shutter for producing subpicosecond pulses with a Nd-glass laser. Furthermore, the liquid component permitted output powers of up to 5 W/sq cm without eliciting thermooptical effects.

Synchronization of video recording and laser pulses including background light suppression

NASA Technical Reports Server (NTRS)

Kalshoven, Jr., James E. (Inventor); Tierney, Jr., Michael (Inventor); Dabney, Philip W. (Inventor)

2004-01-01

An apparatus for and a method of triggering a pulsed light source, in particular a laser light source, for predictable capture of the source by video equipment. A frame synchronization signal is derived from the video signal of a camera to trigger the laser and position the resulting laser light pulse in the appropriate field of the video frame and during the opening of the electronic shutter, if such shutter is included in the camera. Positioning of the laser pulse in the proper video field allows, after recording, for the viewing of the laser light image with a video monitor using the pause mode on a standard cassette-type VCR. This invention also allows for fine positioning of the laser pulse to fall within the electronic shutter opening. For cameras with externally controllable electronic shutters, the invention provides for background light suppression by increasing shutter speed during the frame in which the laser light image is captured. This results in the laser light appearing in one frame in which the background scene is suppressed with the laser light being uneffected, while in all other frames, the shutter speed is slower, allowing for the normal recording of the background scene. This invention also allows for arbitrary (manual or external) triggering of the laser with full video synchronization and background light suppression.

Laser speckle strain and deformation sensor using linear array image cross-correlation method for specifically arranged triple-beam triple-camera configuration

NASA Technical Reports Server (NTRS)

Sarrafzadeh-Khoee, Adel K. (Inventor)

2000-01-01

The invention provides a method of triple-beam and triple-sensor in a laser speckle strain/deformation measurement system. The triple-beam/triple-camera configuration combined with sequential timing of laser beam shutters is capable of providing indications of surface strain and structure deformations. The strain and deformation quantities, the four variables of surface strain, in-plane displacement, out-of-plane displacement and tilt, are determined in closed form solutions.

Design/Use of the Remotely Operated Bakeout Box Shutter (ROBBS)

NASA Technical Reports Server (NTRS)

Ottens, Brian P.

1999-01-01

A thermal vacuum box bakeout and certification allows orbital payloads to be cleaned and certified when the background TQCM measurements (a measure of how much molecular contamination is on a payload or chamber) are unacceptable or unmanageable in the standard thermal vacuum chamber. The box bakeout procedure is usually performed in 4 steps: bakeout the box, certify the box, bake out the payload, and finally certify the payload. In the procedure's current setup, the contaminant conduction hole ("lid") is initially open and a vacuum chamber break must occur between the bakeout and certification phases to close the box from the vacuum chamber. This exposure is necessary to allow the outgassed contaminants to escape the box's volume rapidly during bakeout phase, but payload certification isn't usually performed while the lid is still open, because it exposes the payload, TQCM, and box volume to chamber contaminants. The Remotely Operated Bakeout Box Shutter (ROBBS) is a new facility design and will allow the remote closure of the contamination hole while the chamber is still under vacuum, and with little or no time to do so.

Electrostatically operated optical microshutter array for a miniature integrated optical spectrometer

NASA Astrophysics Data System (ADS)

Ilias, Samir; Picard, Francis; Larouche, Carl; Kruzelecky, Roman; Jamroz, Wes

2017-11-01

16x1 programmable microshutter arrays allowing control of the light transmitted through a transparent substrate supporting the array were successfully fabricated using surface micromachining technology. Each microshutter is basically an electrostatic zipping actuator having a curved shape induced by a stress gradient through the actuator thickness. When a sufficient voltage is applied between the microshutter and the actuation electrode surrounding the associated microslit area, the generated electrostatic force pulls the actuator down to the substrate which closes the microslit. Opening the slit relies on the restoring force. High light transmission through the slit area is obtained with the actuator in the open position and excellent light blocking is observed when the shutter is closed. Static and dynamic responses of the device were determined. The pull-in voltage to close the microslit was about 110 V and the response times to close and open the microslit were about 2 ms and 7 ms, respectively.

Roof aperture system for selective collection and control of solar energy for building heating, cooling and daylighting

DOEpatents

Sanders, William J.; Snyder, Marvin K.; Harter, James W.

1983-01-01

The amount of building heating, cooling and daylighting is controlled by at least one pair of solar energy passing panels, with each panel of the pair of panels being exposed to a separate direction of sun incidence. A shutter-shade combination is associated with each pair of panels and the shutter is connected to the shade so that rectilinear movement of the shutter causes pivotal movement of the shade.

Fast optically sectioned fluorescence HiLo endomicroscopy.

PubMed

Ford, Tim N; Lim, Daryl; Mertz, Jerome

2012-02-01

We describe a nonscanning, fiber bundle endomicroscope that performs optically sectioned fluorescence imaging with fast frame rates and real-time processing. Our sectioning technique is based on HiLo imaging, wherein two widefield images are acquired under uniform and structured illumination and numerically processed to reject out-of-focus background. This work is an improvement upon an earlier demonstration of widefield optical sectioning through a flexible fiber bundle. The improved device features lateral and axial resolutions of 2.6 and 17 μm, respectively, a net frame rate of 9.5 Hz obtained by real-time image processing with a graphics processing unit (GPU) and significantly reduced motion artifacts obtained by the use of a double-shutter camera. We demonstrate the performance of our system with optically sectioned images and videos of a fluorescently labeled chorioallantoic membrane (CAM) in the developing G. gallus embryo. HiLo endomicroscopy is a candidate technique for low-cost, high-speed clinical optical biopsies.

Fast optically sectioned fluorescence HiLo endomicroscopy

NASA Astrophysics Data System (ADS)

Ford, Tim N.; Lim, Daryl; Mertz, Jerome

2012-02-01

We describe a nonscanning, fiber bundle endomicroscope that performs optically sectioned fluorescence imaging with fast frame rates and real-time processing. Our sectioning technique is based on HiLo imaging, wherein two widefield images are acquired under uniform and structured illumination and numerically processed to reject out-of-focus background. This work is an improvement upon an earlier demonstration of widefield optical sectioning through a flexible fiber bundle. The improved device features lateral and axial resolutions of 2.6 and 17 μm, respectively, a net frame rate of 9.5 Hz obtained by real-time image processing with a graphics processing unit (GPU) and significantly reduced motion artifacts obtained by the use of a double-shutter camera. We demonstrate the performance of our system with optically sectioned images and videos of a fluorescently labeled chorioallantoic membrane (CAM) in the developing G. gallus embryo. HiLo endomicroscopy is a candidate technique for low-cost, high-speed clinical optical biopsies.

a Novel Technique for Precision Geometric Correction of Jitter Distortion for the Europa Imaging System and Other Rolling-Shutter Cameras

NASA Astrophysics Data System (ADS)

Kirk, R. L.; Shepherd, M.; Sides, S. C.

2018-04-01

We use simulated images to demonstrate a novel technique for mitigating geometric distortions caused by platform motion ("jitter") as two-dimensional image sensors are exposed and read out line by line ("rolling shutter"). The results indicate that the Europa Imaging System (EIS) on NASA's Europa Clipper can likely meet its scientific goals requiring 0.1-pixel precision. We are therefore adapting the software used to demonstrate and test rolling shutter jitter correction to become part of the standard processing pipeline for EIS. The correction method will also apply to other rolling-shutter cameras, provided they have the operational flexibility to read out selected "check lines" at chosen times during the systematic readout of the frame area.

Pulsed rotating supersonic source for merged molecular beams

NASA Astrophysics Data System (ADS)

Sheffield, L.; Hickey, M. S.; Krasovitskiy, V.; Rathnayaka, K. D. D.; Lyuksyutov, I. F.; Herschbach, D. R.

2012-06-01

We describe a pulsed rotating supersonic beam source, evolved from an ancestral device [M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001)]. The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, cryocooling, and a shutter gate eliminated the main handicap of the original device in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1-0.6 ms (depending on rotor speed) and containing ˜1012 molecules at lab speeds as low as 35 m/s and ˜1015 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, Cl2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when using two merged beams. By closely matching the beam speeds, very low relative collision energies can be attained without making either beam very slow.

Pulsed rotating supersonic source for merged molecular beams

NASA Astrophysics Data System (ADS)

Sheffield, Les; Hickey, Mark; Krasovitskiy, Vitaliy; Rathnayaka, Daya; Lyuksyutov, Igor; Herschbach, Dudley

2012-10-01

We continue the characterization of a pulsed rotating supersonic beam source. The original device was described by M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001). The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, and a shutter gate eliminate the main handicap of the original device in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1--0.6 ms (depending on rotor speed) and containing ˜10^12 molecules at lab speeds as low as 35 m/s and ˜10^15 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when using two merged beams. By closely matching the beam speeds, very low relative collision energies can be attained without making either beam very slow.

Temperature-controlled optical stimulation of the rat prostate cavernous nerves

NASA Astrophysics Data System (ADS)

Tozburun, Serhat; Hutchens, Thomas C.; McClain, Michael A.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

2013-06-01

Optical nerve stimulation (ONS) may be useful as a diagnostic tool for intraoperative identification and preservation of the prostate cavernous nerves (CN), responsible for erectile function, during prostate cancer surgery. Successful ONS requires elevating the nerve temperature to within a narrow range (˜42 to 47°C) for nerve activation without thermal damage to the nerve. This preliminary study explores a prototype temperature-controlled optical nerve stimulation (TC-ONS) system for maintaining a constant (±1°C) nerve temperature during short-term ONS of the rat prostate CNs. A 150-mW, 1455-nm diode laser was operated in continuous-wave mode, with and without temperature control, during stimulation of the rat CNs for 15 to 30 s through a fiber optic probe with a 1-mm-diameter spot. A microcontroller opened and closed an in-line mechanical shutter in response to an infrared sensor, with a predetermined temperature set point. With TC-ONS, higher laser power settings were used to rapidly and safely elevate the CNs to a temperature necessary for a fast intracavernous pressure response, while also preventing excessive temperatures that would otherwise cause thermal damage to the nerve. With further development, TC-ONS may provide a rapid, stable, and safe method for intraoperative identification and preservation of the prostate CNs.

Ultra-fast high-resolution hybrid and monolithic CMOS imagers in multi-frame radiography

NASA Astrophysics Data System (ADS)

Kwiatkowski, Kris; Douence, Vincent; Bai, Yibin; Nedrow, Paul; Mariam, Fesseha; Merrill, Frank; Morris, Christopher L.; Saunders, Andy

2014-09-01

A new burst-mode, 10-frame, hybrid Si-sensor/CMOS-ROIC FPA chip has been recently fabricated at Teledyne Imaging Sensors. The intended primary use of the sensor is in the multi-frame 800 MeV proton radiography at LANL. The basic part of the hybrid is a large (48×49 mm2) stitched CMOS chip of 1100×1100 pixel count, with a minimum shutter speed of 50 ns. The performance parameters of this chip are compared to the first generation 3-frame 0.5-Mpixel custom hybrid imager. The 3-frame cameras have been in continuous use for many years, in a variety of static and dynamic experiments at LANSCE. The cameras can operate with a per-frame adjustable integration time of ~ 120ns-to- 1s, and inter-frame time of 250ns to 2s. Given the 80 ms total readout time, the original and the new imagers can be externally synchronized to 0.1-to-5 Hz, 50-ns wide proton beam pulses, and record up to ~1000-frame radiographic movies typ. of 3-to-30 minute duration. The performance of the global electronic shutter is discussed and compared to that of a high-resolution commercial front-illuminated monolithic CMOS imager.

Active pixel sensor array with electronic shuttering

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor)

2002-01-01

An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

Shutter mechanism for spacecraft spectrophotometer

NASA Technical Reports Server (NTRS)

Weilbach, A.

1972-01-01

A shutter mechanism is described for the backscatter ultraviolet spectrophotometer experiment on the Nimbus D satellite. The purpose of the experiment is to determine spatial distribution of atmospheric ozone from measurements of ultraviolet radiation backscattered by the earth's atmosphere. The system consists of two independent, rotary cylinder shutters, controlled by a dual star Geneva mechanism, and driven by a single stepper motor. A single driver controls a combination of two independently driven Geneva stars. Design considerations involved the use of low friction, nonmetallic materials.

A Low Power Cryogenic Shutter Mechanism for use in Infrared Images

NASA Technical Reports Server (NTRS)

Schwinger, D. Scott; Hakun, Claef F.

2000-01-01

This paper discusses the requirements, design, operation, and testing of the shutter mechanism for the Infrared Array Camera (IRAC). The shutter moves a mirror panel into or out of the incoming light path transitioning IRAC between data acquisition and calibration modes. The mechanism features a torsion flexure suspension system, two low-power rotary actuators, a balanced shaft, and a variable reluctance position sensor. Each of these items is discussed along with problems encountered during development and the implemented solutions.

A PC-based shutter glasses controller for visual stimulation using multithreading in LabWindows/CVI.

PubMed

Gramatikov, Ivan; Simons, Kurt; Guyton, David; Gramatikov, Boris

2017-05-01

Amblyopia, commonly known as "lazy eye," is poor vision in an eye from prolonged neurologic suppression. It is a major public health problem, afflicting up to 3.6% of children, and will lead to lifelong visual impairment if not identified and treated in early childhood. Traditional treatment methods, such as occluding or penalizing the good eye with eye patches or blurring eye drops, do not always yield satisfactory results. Newer methods have emerged, based on liquid crystal shutter glasses that intermittently occlude the better eye, or alternately occlude the two eyes, thus stimulating vision in the "lazy" eye. As yet there is no technology that allows easy and efficient optimization of the shuttering characteristics for a given individual. The purpose of this study was to develop an inexpensive, computer-based system to perform liquid crystal shuttering in laboratory and clinical settings to help "wake up" the suppressed eye in amblyopic patients, and to help optimize the individual shuttering parameters such as wave shape, level of transparency/opacity, frequency, and duty cycle of the shuttering. We developed a liquid crystal glasses controller connected by USB cable to a PC computer. It generates the voltage waveforms going to the glasses, and has potentiometer knobs for interactive adjustments by the patient. In order to achieve good timing performance in this bidirectional system, we used multithreading programming techniques with data protection, implemented in LabWindows/CVI. The hardware and software developed were assessed experimentally. We achieved an accuracy of ±1Hz for the frequency, and ±2% for the duty cycle of the occlusion pulses. We consider these values to be satisfactory for the purpose of optimizing the visual stimulation by means of shutter glasses. The system can be used for individual optimization of shuttering attributes by clinicians, for training sessions in clinical settings, or even at home, aimed at stimulating vision in the "lazy" eye. Multithreading offers significant benefits for data acquisition and instrument control, making it possible to implement time-efficient algorithms in inexpensive yet versatile medical instrumentation with only minimum requirements on the hardware. Copyright © 2017 Elsevier B.V. All rights reserved.

6. DETAIL EXTERIOR VIEW OF WINDOW SHUTTERS ON OUTSIDE OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. DETAIL EXTERIOR VIEW OF WINDOW SHUTTERS ON OUTSIDE OF FISH HATCHERY BUILDING. - Bonneville Project, Fish Hatchery, On Columbia River bordered on South by Union Pacific, Bonneville, Multnomah County, OR

Electronic trigger for capacitive touchscreen and extension of ISO 15781 standard time lag measurements to smartphones

NASA Astrophysics Data System (ADS)

Bucher, François-Xavier; Cao, Frédéric; Viard, Clément; Guichard, Frédéric

2014-03-01

We present in this paper a novel capacitive device that stimulates the touchscreen interface of a smartphone (or of any imaging device equipped with a capacitive touchscreen) and synchronizes triggering with the DxO LED Universal Timer to measure shooting time lag and shutter lag according to ISO 15781:2013. The device and protocol extend the time lag measurement beyond the standard by including negative shutter lag, a phenomenon that is more and more commonly found in smartphones. The device is computer-controlled, and this feature, combined with measurement algorithms, makes it possible to automatize a large series of captures so as to provide more refined statistical analyses when, for example, the shutter lag of "zero shutter lag" devices is limited by the frame time as our measurements confirm.

IR Sensor Synchronizing Active Shutter Glasses for 3D HDTV with Flexible Liquid Crystal Lenses

PubMed Central

Han, Jeong In

2013-01-01

IR sensor synchronizing active shutter glasses for three-dimensional high definition television (3D HDTV) were developed using a flexible liquid crystal (FLC) lens. The FLC lens was made on a polycarbonate (PC) substrate using conventional liquid crystal display (LCD) processes. The flexible liquid crystal lens displayed a maximum transmission of 32% and total response time of 2.56 ms. The transmittance, the contrast ratio and the response time of the flexible liquid crystal lens were superior to those of glass liquid crystal lenses. Microcontroller unit and drivers were developed as part of a reception module with power supply for the IR sensor synchronizing active shutter glasses with the flexible liquid crystal lens prototypes. IR sensor synchronizing active shutter glasses for 3D HDTV with flexible liquid crystal lenses produced excellent 3D images viewing characteristics.

Development of a drive system for a sequential space camera

NASA Technical Reports Server (NTRS)

Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

1976-01-01

An electronically commutated dc motor is reported for driving the camera claw and magazine, and a stepper motor is described for driving the shutter with the two motors synchronized electrically. Subsequent tests on the breadboard positively proved the concept, but further development beyond this study should be done. The breadboard testing also established that the electronically commutated motor can control speed over a wide dynamic range, and has a high torque capability for accelerating loads. This performance suggested the possibility of eliminating the clutch from the system while retaining all of the other mechanical features of the DAC, if the requirement for independent shutter speeds and frame rates can be removed. Therefore, as a final step in the study, the breadboard shutter and shutter drive were returned to the original DAC configuration, while retaining the brushless dc motor drive.

[Evaluation of Sugar Content of Huanghua Pear on Trees by Visible/Near Infrared Spectroscopy].

PubMed

Liu, Hui-jun; Ying, Yi-bin

2015-11-01

A method of ambient light correction was proposed to evaluate the sugar content of Huanghua pears on tree by visible/near infrared diffuse reflectance spectroscopy (Vis/NIRS). Due to strong interference of ambient light, it was difficult to collect the efficient spectral of pears on tree. In the field, covering the fruits with a bag blocking ambient light can get better results, but the efficiency is fairly low, the instrument corrections of dark and reference spectra may help to reduce the error of the model, however, the interference of the ambient light cannot be eliminated effectively. In order to reduce the effect of ambient light, a shutter was attached to the front of probe. When opening shutter, the spot spectrum were obtained, on which instrument light and ambient light acted at the same time. While closing shutter, background spectra were obtained, on which only ambient light acted, then the ambient light spectra was subtracted from spot spectra. Prediction models were built using data on tree (before and after ambient light correction) and after harvesting by partial least square (PLS). The results of the correlation coefficient (R) are 0.1, 0.69, 0.924; the root mean square error of prediction (SEP) are 0. 89°Brix, 0.42°Brix, 0.27°Brix; ratio of standard deviation (SD) to SEP (RPD) are 0.79, 1.69, 2.58, respectively. The results indicate that, method of background correction used in the experiment can reduce the effect of ambient lighting on spectral acquisition of Huanghua pears in field, efficiently. This method can be used to collect the visible/near infrared spectrum of fruits in field, and may give full play to visible/near-infrared spectroscopy in preharvest management and maturity testing of fruits in the field.

ISOTOPE SEPARATING APPARATUS

DOEpatents

Kudravetz, M.K.; Greene, H.B.

1958-09-16

This patent relates to control systems for a calutron and, in particular, describes an electro-mechanical system for interrupting the collection of charged particles when the ratio between the two isotopes being receivcd deviates from a predetermined value. One embodiment of the invention includes means responsive to the ratio between two isotopes being received for opening a normally closed shutter over the receiver entrance when the isotope ratio is the desired value. In another form of the invention the collection operation is interrupted by changing the beam accelerating voltage to deflect the ion beam away from the receiver.

Shielding Analyses for VISION Beam Line at SNS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popova, Irina; Gallmeier, Franz X

2014-01-01

Full-scale neutron and gamma transport analyses were performed to design shielding around the VISION beam line, instrument shielding enclosure, beam stop, secondary shutter including a temporary beam stop for the still closed neighboring beam line to meet requirement is to achieve dose rates below 0.25 mrem/h at 30 cm from the shielding surface. The beam stop and the temporary beam stop analyses were performed with the discrete ordinate code DORT additionally to Monte Carlo analyses with the MCNPX code. Comparison of the results is presented.

Micro-optical system based 3D imaging for full HD depth image capturing

NASA Astrophysics Data System (ADS)

Park, Yong-Hwa; Cho, Yong-Chul; You, Jang-Woo; Park, Chang-Young; Yoon, Heesun; Lee, Sang-Hun; Kwon, Jong-Oh; Lee, Seung-Wan

2012-03-01

20 Mega-Hertz-switching high speed image shutter device for 3D image capturing and its application to system prototype are presented. For 3D image capturing, the system utilizes Time-of-Flight (TOF) principle by means of 20MHz high-speed micro-optical image modulator, so called 'optical shutter'. The high speed image modulation is obtained using the electro-optic operation of the multi-layer stacked structure having diffractive mirrors and optical resonance cavity which maximizes the magnitude of optical modulation. The optical shutter device is specially designed and fabricated realizing low resistance-capacitance cell structures having small RC-time constant. The optical shutter is positioned in front of a standard high resolution CMOS image sensor and modulates the IR image reflected from the object to capture a depth image. Suggested novel optical shutter device enables capturing of a full HD depth image with depth accuracy of mm-scale, which is the largest depth image resolution among the-state-of-the-arts, which have been limited up to VGA. The 3D camera prototype realizes color/depth concurrent sensing optical architecture to capture 14Mp color and full HD depth images, simultaneously. The resulting high definition color/depth image and its capturing device have crucial impact on 3D business eco-system in IT industry especially as 3D image sensing means in the fields of 3D camera, gesture recognition, user interface, and 3D display. This paper presents MEMS-based optical shutter design, fabrication, characterization, 3D camera system prototype and image test results.

12. Detail, typical window with fireproof shutters open, northeast rear, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Detail, typical window with fireproof shutters open, northeast rear, view to southwest, 135mm lens. Note cracks evidencing structural failure. - Benicia Arsenal, Powder Magazine No. 5, Junction of Interstate Highways 680 & 780, Benicia, Solano County, CA

WINDOW WITH ORIGINAL PANELED FOLDING SHUTTERS, SECOND FLOOR FRONT ROOM, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

WINDOW WITH ORIGINAL PANELED FOLDING SHUTTERS, SECOND FLOOR FRONT ROOM, LOOKING OUT WALNUT STREET (SOUTH). NOTE ALTERED LOWER SECTION MADE CA. 1840. Compare window in PA-1436 A-37 - Kid-Chandler House, 323 Walnut Street, Philadelphia, Philadelphia County, PA

Image reproduction with interactive graphics

NASA Technical Reports Server (NTRS)

Buckner, J. D.; Council, H. W.; Edwards, T. R.

1974-01-01

Software application or development in optical image digital data processing requires a fast, good quality, yet inexpensive hard copy of processed images. To achieve this, a Cambo camera with an f 2.8/150-mm Xenotar lens in a Copal shutter having a Graflok back for 4 x 5 Polaroid type 57 pack-film has been interfaced to an existing Adage, AGT-30/Electro-Mechanical Research, EMR 6050 graphic computer system. Time-lapse photography in conjunction with a log to linear voltage transformation has resulted in an interactive system capable of producing a hard copy in 54 sec. The interactive aspect of the system lies in a Tektronix 4002 graphic computer terminal and its associated hard copy unit.

DCE-MRI of hepatocellular carcinoma: perfusion quantification with Tofts model versus shutter-speed model--initial experience.

PubMed

Jajamovich, Guido H; Huang, Wei; Besa, Cecilia; Li, Xin; Afzal, Aneela; Dyvorne, Hadrien A; Taouli, Bachir

2016-02-01

To quantify hepatocellular carcinoma (HCC) perfusion and flow with the fast exchange regime-allowed Shutter-Speed model (SSM) compared to the Tofts model (TM). In this prospective study, 25 patients with HCC underwent DCE-MRI. ROIs were placed in liver parenchyma, portal vein, aorta and HCC lesions. Signal intensities were analyzed employing dual-input TM and SSM models. ART (arterial fraction), K (trans) (contrast agent transfer rate constant from plasma to extravascular extracellular space), ve (extravascular extracellular volume fraction), kep (contrast agent intravasation rate constant), and τi (mean intracellular water molecule lifetime) were compared between liver parenchyma and HCC, and ART, K (trans), v e and k ep were compared between models using Wilcoxon tests and limits of agreement. Test-retest reproducibility was assessed in 10 patients. ART and v e obtained with TM; ART, ve, ke and τi obtained with SSM were significantly different between liver parenchyma and HCC (p < 0.04). Parameters showed variable reproducibility (CV range 14.7-66.5% for both models). Liver K (trans) and ve; HCC ve and kep were significantly different when estimated with the two models (p < 0.03). Our results show differences when computed between the TM and the SSM. However, these differences are smaller than parameter reproducibilities and may be of limited clinical significance.

An efficient shutter-less non-uniformity correction method for infrared focal plane arrays

NASA Astrophysics Data System (ADS)

Huang, Xiyan; Sui, Xiubao; Zhao, Yao

2017-02-01

The non-uniformity response in infrared focal plane array (IRFPA) detectors has a bad effect on images with fixed pattern noise. At present, it is common to use shutter to prevent from radiation of target and to update the parameters of non-uniformity correction in the infrared imaging system. The use of shutter causes "freezing" image. And inevitably, there exists the problems of the instability and reliability of system, power consumption, and concealment of infrared detection. In this paper, we present an efficient shutter-less non-uniformity correction (NUC) method for infrared focal plane arrays. The infrared imaging system can use the data gaining in thermostat to calculate the incident infrared radiation by shell real-timely. And the primary output of detector except the shell radiation can be corrected by the gain coefficient. This method has been tested in real infrared imaging system, reaching high correction level, reducing fixed pattern noise, adapting wide temperature range.

Delay time in a single barrier for a movable quantum shutter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernandez, Alberto

2010-05-15

The transient solution and delay time for a {delta} potential scatterer with a movable quantum shutter is calculated by solving analytically the time-dependent Schroedinger equation. The delay time is analyzed as a function of the distance between the shutter and the potential barrier and also as a function of the distance between the potential barrier and the detector. In both cases, it is found that the delay time exhibits a dynamical behavior and that it tends to a saturation value {Delta}t{sub sat} in the limit of very short distances, which represents the maximum delay produced by the potential barrier nearmore » the interaction region. The phase time {tau}{sub {theta},} on the other hand, is not an appropriate time scale for measuring the time delay near the interaction region, except if the shutter is moved far away from the potential. The role played by the antibound state of the system on the behavior of the delay time is also discussed.« less

Fast optically sectioned fluorescence HiLo endomicroscopy

PubMed Central

Lim, Daryl; Mertz, Jerome

2012-01-01

Abstract. We describe a nonscanning, fiber bundle endomicroscope that performs optically sectioned fluorescence imaging with fast frame rates and real-time processing. Our sectioning technique is based on HiLo imaging, wherein two widefield images are acquired under uniform and structured illumination and numerically processed to reject out-of-focus background. This work is an improvement upon an earlier demonstration of widefield optical sectioning through a flexible fiber bundle. The improved device features lateral and axial resolutions of 2.6 and 17 μm, respectively, a net frame rate of 9.5 Hz obtained by real-time image processing with a graphics processing unit (GPU) and significantly reduced motion artifacts obtained by the use of a double-shutter camera. We demonstrate the performance of our system with optically sectioned images and videos of a fluorescently labeled chorioallantoic membrane (CAM) in the developing G. gallus embryo. HiLo endomicroscopy is a candidate technique for low-cost, high-speed clinical optical biopsies. PMID:22463023

Fabrication of a dye-doped liquid crystal light shutter by thermal curing of polymer

NASA Astrophysics Data System (ADS)

Yu, Byeong-Hun; Ji, Seong-Min; Kim, Jin-Hun; Huh, Jae-Won; Yoon, Tae-Hoon

2017-07-01

We report a thermal curing method for fabrication of a dye-doped polymer-stabilized liquid crystal (PSLC) light shutter, which can prevent the decrease in absorption and discoloration of the dye caused by the UV curing process. We found that the measured transmittance in the opaque state of a dye-doped PSLC cell fabricated by thermal curing was approximately 35% lower than that of a dye-doped PSLC cell fabricated by UV curing. Thermal curing can be an alternative approach for fabrication of a dye-doped PSLC light shutter which can be used to provide high visibility of a see-through display.

Development of fire shutters based on numerical optimizations

NASA Astrophysics Data System (ADS)

Novak, Ondrej; Kulhavy, Petr; Martinec, Tomas; Petru, Michal; Srb, Pavel

2018-06-01

This article deals with a prototype concept, real experiment and numerical simulation of a layered industrial fire shutter, based on some new insulating composite materials. The real fire shutter has been developed and optimized in laboratory and subsequently tested in the certified test room. A simulation of whole concept has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results - i.e. thermal distribution inside and heat release rate that has gone through the sample.

Long-term Stability of the Post-Flash LED Lamp

NASA Astrophysics Data System (ADS)

Martlin, Catherine; Baggett, Sylvia

2017-02-01

We report the results of a study of the long-term stability of the LED lamp used in post-flashing WFC3/UVIS images. We analyze 644 sub-array exposures taken over the course of just over 3 years and find no significant long-term trends in the LED lamp brightness. The average percentage change per year over all FLASH level and shutter combinations is found to be 0.15% per year with an uncertainty of ± 0.24% per year. The maximum measured percentage change per year was 0.39% for the highest FLASH level of 20 e- on shutter A which would indicate a change of less than 1 e-/pixel over the roughly 3 years since post-flashing began. There are, however, occasional short-term deviations in the LED output. The average minimum and maximum outliers over all FLASH level and shutter combination subsets are 4.1% below and 3.5% above, respectively, the mean of that subset. The maximum outlier over all the sets is 5.8% above the normalized mean value, for FLASH level 3/shutter A. The minimum outlier over all sets is also for FLASH level 3/shutter A and is 8.9% below the normalized mean value. Investigation of these outliers has revealed no systematic cause for the excursions and we recommend that users continue using the post-flash as they would have previously.

Solar concentrator protective system

NASA Technical Reports Server (NTRS)

Selcuk, M. K. (Inventor)

1984-01-01

A mechanism that blocks concentrated sunlight from reaching a receiver, in the event of a tracking failure or loss of coolant is described. Sunlight is normally concentrated by a dish reflector onto the opening of a receiver. A faceplate surrounds the opening, and coolant carrying tubes, line the receiver. If the concentrated sunlight wanders so it begins to fall on the faceplate, then the sunlight will melt a portion of a fuse wire portion will break. The wire is attached to a flange on a shutter frame, and breaking of the fuse wire allows the frame to fall. Normally, the shutter frame supports shutter elements that are held open by cam followers that bear against cams.

Axial flow plasma shutter

DOEpatents

Krausse, George J.

1988-01-01

A shutter (36) is provided for controlling a beam, or current, of charged particles in a device such as a thyratron (10). The substrate (38) defines an aperture (60) with a gap (32) which is placeable within the current. Coils (48) are formed on the substrate (38) adjacent the aperture (60) to produce a magnetic field for trapping the charged particles in or about aperture (60). The proximity of the coils (48) to the aperture (60) enables an effective magnetic field to be generated by coils (48) having a low inductance suitable for high frequency control. The substantially monolithic structure including the substrate (38) and coils (48) enables the entire shutter assembly (36) to be effectively located with respect to the particle beam.

Magnetic Characterization of Micro Shutters for James Web Space Telescope (JWST)

NASA Technical Reports Server (NTRS)

Wasilewski, P. (Technical Monitor); Kletetschka, Gunther

2005-01-01

Summary of Research that was part of the grant: NASA NAG5 - 13405: Magnetic Characterization of Micro Shutters for James Web Space Telescope (JWST) Period: May 1 2003-October 31 2005 The above funding resulted in following major achievements related to microshutter system for JWST. 1. The original rectangular pattern of magnetic material was changed into magnetic striped pattern to prevent unnecessary twisting during the actuation. The Original geometry favored magnetic remanence vector being oriented along the longer side of the shutter and thus resulting torque caused out of plane twist. Stripe pattern minimizes the out of plane motion and thus prolongs the life-time of microshutter device. 2. We built a new magnetic system (magnetic rotisserie) allowing an accelerated life test of microshutters at various temperatures. This system identified that shutter are capable to withstand as many as several millions of actuating cycles. Our system also identified fabrication related features, like bowing with temperature, collisions with the frame due to misalignment, delaminating of the light shields due to uncontrolled voltage release and poorly fabricated light shields.

Long-term Stability of the WFC3 Post-Flash LED Lamp

NASA Astrophysics Data System (ADS)

Martlin, Catherine; Baggett, Sylvia M.

2017-06-01

We report the results of a study of the long-term stability of the LED lamp used in post-flashing WFC3/UVIS images (Martlin, C and Baggett, S., 2017). Having analyzed 644 sub-array exposures taken over the course of just over 3 years we find no significant long-term trends in the LED lamp brightness. The average percentage change per year over all FLASH level and shutter combinations is found to be 0.15% per year with an uncertainty of +/- 0.24% per year. The maximum measured percentage change per year was 0.39% for the highest FLASH level of 20 e- on shutter A which would indicate a change of less than 1 e-/pixel over the roughly 3 years since post-flashing began.There are, however, occasional short-term deviations in the LED output. The average minimum and maximum outliers over all FLASH level and shutter combination subsets are 4.1% below and 3.5% above, respectively, the mean of that subset. The maximum outlier over all the sets is 5.8% above the normalized mean value, for FLASH level 3/shutter A. The minimum outlier over all sets is also for FLASH level 3/shutter A and is 8.9% below the normalized mean value. Investigation of these outliers has revealed no systematic cause for the excursions and we recommend that users continue using the post-flash as they would have previously.

Real-time film recording from stroke-written CRT's

NASA Technical Reports Server (NTRS)

Hunt, R.; Grunwald, A. J.

1980-01-01

Real-time simulation studies often require motion-picture recording of events directly from stroke written cathode-ray tubes (CRT's). Difficulty presented is prevention of "flicker," which results from lack of synchronization between display sequence on CRT and shutter motion of camera. Programmable method has been devised for phasing display sequence to shutter motion, ensuring flicker-free recordings.

Design and Manufacture of a Highly Reliable, Miniaturized and Low Mass Shutter Mechanism

NASA Technical Reports Server (NTRS)

Manhart, M.; Zeh, T.; Preibler, G.; Hurni, A.; Walter, I.; Helbert, J.; Hiesinger, H.

2010-01-01

This paper describes the development, manufacturing and testing of a lightweight shutter mechanism made of titanium for the MERTIS Instrument. MERTIS is a thermal infrared imaging spectrometer onboard ESA's future BepiColombo mission to Mercury. The mechanism is built as a parallelogram arrangement of flexible hinges, actuated by a voice coil. In a first test run, it was shown that the selected EDM processing led to the generation of titanium oxides and an oxygen-enriched surface layer on the substrate (so called alpha-case layer). In the revised version of the shutter, it was possible to manufacture the complex geometry by micro-milling and an adjacent pickling procedure. The adequacy of this approach was verified by lifetime and vibration testing.

A high throughput liquid crystal light shutter for unpolarized light using polymer polarization gratings

NASA Astrophysics Data System (ADS)

Komanduri, Ravi K.; Lawler, Kris F.; Escuti, Michael J.

2011-05-01

We report on a broadband, diffractive, light shutter with the ability to modulate unpolarized light. This polarizer-free approach employs a conventional liquid crystal (LC) switch, combined with broadband Polarization Gratings (PGs) formed with polymer LC materials. The thin-film PGs act as diffractive polarizing beam-splitters, while the LC switch operates on both orthogonal polarization states simultaneously. As an initial experimental proof-of- concept for unpolarized light with +/-7° aperture, we utilize a commercial twisted-nematic LC switch and our own polymer PGs to achieve a peak transmittance of 80% and peak contrast ratio of 230:1. We characterize the optoelectronic performance, discuss the limitations, and evaluate its use in potential nonmechanical shutter applications (imaging and non-imaging).

Wobbly strings: calculating the capture rate of a webcam using the rolling shutter effect in a guitar

NASA Astrophysics Data System (ADS)

Cunnah, David

2014-07-01

In this paper I propose a method of calculating the time between line captures in a standard complementary metal-oxide-semiconductor (CMOS) webcam using the rolling shutter effect when filming a guitar. The exercise links the concepts of wavelength and frequency, while outlining the basic operation of a CMOS camera through vertical line capture.

Wobbly Strings: Calculating the Capture Rate of a Webcam Using the Rolling Shutter Effect in a Guitar

ERIC Educational Resources Information Center

Cunnah, David

2014-01-01

In this paper I propose a method of calculating the time between line captures in a standard complementary metal-oxide-semiconductor (CMOS) webcam using the rolling shutter effect when filming a guitar. The exercise links the concepts of wavelength and frequency, while outlining the basic operation of a CMOS camera through vertical line capture.

Design and characterization of the ePix10k: a high dynamic range integrating pixel ASIC for LCLS detectors

NASA Astrophysics Data System (ADS)

Caragiulo, P.; Dragone, A.; Markovic, B.; Herbst, R.; Nishimura, K.; Reese, B.; Herrmann, S.; Hart, P.; Blaj, G.; Segal, J.; Tomada, A.; Hasi, J.; Carini, G.; Kenney, C.; Haller, G.

2015-05-01

ePix10k is a variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. The ASIC is optimized for high dynamic range application requiring high spatial resolution and fast frame rates. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per column. The ePix10k variant has 100um×100um pixels arranged in a 176×192 matrix, a resolution of 140e- r.m.s. and a signal range of 3.5pC (10k photons at 8keV). In its final version it will be able to sustain a frame rate of 2kHz. A first prototype has been fabricated and characterized. Performance in terms of noise, linearity, uniformity, cross-talk, together with preliminary measurements with bump bonded sensors are reported here.

Configuring and Characterizing X-Rays for Laser-Driven Compression Experiments at the Dynamic Compression Sector

NASA Astrophysics Data System (ADS)

Li, Y.; Capatina, D.; D'Amico, K.; Eng, P.; Hawreliak, J.; Graber, T.; Rickerson, D.; Klug, J.; Rigg, P. A.; Gupta, Y. M.

2017-06-01

Coupling laser-driven compression experiments to the x-ray beam at the Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS) of Argonne National Laboratory requires state-of-the-art x-ray focusing, pulse isolation, and diagnostics capabilities. The 100J UV pulsed laser system can be fired once every 20 minutes so precise alignment and focusing of the x-rays on each new sample must be fast and reproducible. Multiple Kirkpatrick-Baez (KB) mirrors are used to achieve a focal spot size as small as 50 μm at the target, while the strategic placement of scintillating screens, cameras, and detectors allows for fast diagnosis of the beam shape, intensity, and alignment of the sample to the x-ray beam. In addition, a series of x-ray choppers and shutters are used to ensure that the sample is exposed to only a single x-ray pulse ( 80ps) during the dynamic compression event and require highly precise synchronization. Details of the technical requirements, layout, and performance of these instruments will be presented. Work supported by DOE/NNSA.

Submillisecond fireball timing using de Bruijn timecodes

NASA Astrophysics Data System (ADS)

Howie, Robert M.; Paxman, Jonathan; Bland, Philip A.; Towner, Martin C.; Sansom, Eleanor K.; Devillepoix, Hadrien A. R.

2017-08-01

Long-exposure fireball photographs have been used to systematically record meteoroid trajectories, calculate heliocentric orbits, and determine meteorite fall positions since the mid-20th century. Periodic shuttering is used to determine meteoroid velocity, but up until this point, a separate method of precisely determining the arrival time of a meteoroid was required. We show it is possible to encode precise arrival times directly into the meteor image by driving the periodic shutter according to a particular pattern—a de Bruijn sequence—and eliminate the need for a separate subsystem to record absolute fireball timing. The Desert Fireball Network has implemented this approach using a microcontroller driven electro-optic shutter synchronized with GNSS UTC time to create small, simple, and cost-effective high-precision fireball observatories with submillisecond timing accuracy.

Apparatus for accurately measuring high temperatures

DOEpatents

Smith, D.D.

The present invention is a thermometer used for measuring furnace temperatures in the range of about 1800/sup 0/ to 2700/sup 0/C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

Apparatus for accurately measuring high temperatures

DOEpatents

Smith, Douglas D.

1985-01-01

The present invention is a thermometer used for measuring furnace temperaes in the range of about 1800.degree. to 2700.degree. C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

HIGH SPEED CAMERA

DOEpatents

Rogers, B.T. Jr.; Davis, W.C.

1957-12-17

This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

Nd:YAP laser pulse compression by three-stage transient stimulated Brillouin and Raman scattering

NASA Astrophysics Data System (ADS)

Kubeček, V.; Hamal, K.; Procházka, I.; Buzelis, R.; Girdauskas, V.; Dementiev, A.

1991-08-01

There is a continuous effort to generate stable, powerful picosecond laser pulses for application in spectroscopy, nonlinear optics and parametric light generation, as well. One of the possible methods is the compression of longer nanosecond laser pulses by stimulated Brillouin and stimulated Raman scattering. The advantages of such a technique, in comparison to the used mode locked picosecond lasers, are as follows: the absence of the active and/or passive mode lockers used to generate a train of picosecond pulses, and the absence of a fast electrooptical shutter used to select a single pulse from a train of pulses. The application of stimulated Brillouin and stimulated Raman scattering permits to generate picosecond pulses in the wavelength regions not covered by mode locked lasers. Of special interest is the wavelength region of 0·8 μm, which may be amplified by the attractive Titanium Sapphire lasers. In this paper we are summarizing our results in theoretical modelling and in real generation of picosecond pulses by means of cascaded stimulated Brillouin and Raman scattering. The models of scattering processes have been investigated. The stable generation of 5, 7, 3 picosecond pulses have been optimized for the wavelengths of 0·8, 0·64 and 0·54 μm, respectively. In all these cases, the pulses exhibited the far field pattern close to Gaussian, with the pulse energy ranging from 0·2 to 1 mJ.

New hardware and software platform for experiments on a HUBER-5042 X-ray diffractometer with a DISPLEX DE-202 helium cryostat in the temperature range of 20-300 K

NASA Astrophysics Data System (ADS)

Dudka, A. P.; Antipin, A. M.; Verin, I. A.

2017-09-01

Huber-5042 diffractometer with a closed-cycle Displex DE-202 helium cryostat is a unique scientific instrument for carrying out X-ray diffraction experiments when studying the single crystal structure in the temperature range of 20-300 K. To make the service life longer and develop new experimental techniques, the diffractometer control is transferred to a new hardware and software platform. To this end, a modern computer; a new detector reader unit; and new control interfaces for stepper motors, temperature controller, and cryostat vacuum pumping system are used. The system for cooling the X-ray tube, the high-voltage generator, and the helium compressor and pump for maintaining the desired vacuum in the cryostat are replaced. The system for controlling the primary beam shutter is upgraded. A biological shielding is installed. The new program tools, which use the Linux Ubuntu operating system and SPEC constructor, include a set of drivers for control units through the aforementioned interfaces. A program for searching reflections from a sample using fast continuous scanning and a priori information about crystal is written. Thus, the software package for carrying out the complete cycle of precise diffraction experiment (from determining the crystal unit cell to calculating the integral reflection intensities) is upgraded. High quality of the experimental data obtained on this equipment is confirmed in a number of studies in the temperature range from 20 to 300 K.

Surveillance of Space Concept Demonstrator. Presentation of One Sensor: CASTOR-V

DTIC Science & Technology

2007-04-01

30ºC to minimize the significant dark count (noise) gradient, and that the highest binning mode that will not incur resolution loss must be selected...38 5.1.4 Dome issue 3: Shutter malfunctioning...Dome motor and its controller used to rotate the observatory dome of CASTOR-V10 Figure 8. Dome shutter and wind screen motors and the controller

Low-Light-Shift Cesium Fountain without Mechanical Shutters

NASA Technical Reports Server (NTRS)

Enzer, Daphna

2008-01-01

A new technique for reducing errors in a laser-cooled cesium fountain frequency standard provides for strong suppression of the light shift without need for mechanical shutters. Because mechanical shutters are typically susceptible to failure after operating times of the order of months, the elimination of mechanical shutters could contribute significantly to the reliability of frequency standards that are required to function continuously for longer time intervals. With respect to the operation of an atomic-fountain frequency standard, the term "light shift" denotes an undesired relative shift in the two energy levels of the atoms (in this case, cesium atoms) in the atomic fountain during interrogation by microwaves. The shift in energy levels translates to a frequency shift that reduces the precision and possibly accuracy of the frequency standard. For reasons too complex to describe within the space available for this article, the light shift is caused by any laser light that reaches the atoms during the microwave- interrogation period, but is strongest for near-resonance light. In the absence of any mitigating design feature, the light shift, expressed as a fraction of the standard fs frequency, could be as large as approx. 2 x 10(exp -11), the largest error in the standard. In a typical prior design, to suppress light shift, the intensity of laser light is reduced during the interrogation period by using a single-pass acoustooptic modulator to deflect the majority of light away from the main optical path. Mechanical shutters are used to block the remaining undeflected light to ensure complete attenuation. Without shutters, this remaining undeflected light could cause a light shift of as much as .10.15, which is unacceptably large in some applications. The new technique implemented here involves additionally shifting the laser wavelength off resonance by a relatively large amount (typically of the order of nanometers) during microwave interrogation. In this design, when microwave interrogation is not underway, the atoms are illuminated by a slave laser locked to the lasing frequency of a lower power master laser.

High-speed electromechanical chutter for imaging spectrographs

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet (Inventor)

2005-01-01

The present invention presents a high-speed electromechanical shutter which has at least two rotary beam choppers that are synchronized using a phase-locked loop electronic control to reduce the duty cycle. These choppers have blade means that can comprise discs or drums, each having about 60 (+/- 15) slots which are from about 0.3 to about 0.8 mm wide and about 5 to about 20 nun long (radially) which are evenly distributed through out 360 deg, and a third rotary chopper which is optically aligned has a small number of slots, such as for example, 1 to 10 slots which are about 1 to about 2 mm wide and about 5 to about 20 mm long (radially). Further the blade means include phase slots that allow the blade means to be phase locked using a closed loop control circuit. In addition, in a preferred embodiment, the system also has a leaf shutter. Thus the invention preferably achieves a gate width of less than about 100 microseconds, using motors that operate at 3000 to 10,OOO rpm, and with a phase jitter of less than about 1.5 microseconds, and further using an aperture with more than about 75% optical transmission with a clear aperture of about 0.8 -10 nun. The system can be synchronized to external sources at 0 6 kHz lasers, data acquisition systems, and cameras.

Low energy high angular resolution neutral atom detection by means of micro-shuttering techniques: the BepiColombo SERENA/ELENA unit development

NASA Astrophysics Data System (ADS)

Orsini, S.; di Lellis, A. M.; Milillo, A.; Selci, S.; Leoni, R.; Dandouras, I.

2009-04-01

ELENA (Emitted Low-Energy Neutral Atoms) is a Time-of-Flight (ToF) system, based on oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical gratings devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E ~5 keV. This new kind of low energetic neutral atoms instrument is one of the four units of the SERENA experiment for the ESA cornerstone BepiColombo mission to Mercury. The low energetic neutral particles that are likely to be detected by ELENA come primarily from ion-sputtering process, and secondarily from back-scattering and from charge exchange. ELENA will resolve intensity, velocity and direction of the incoming particle flux: the entrance of the start section (an aperture of about 1 cm2consisting of two self-standing silicon nitride (Si3N4) membranes, patterned with arrays of long and narrow openings) allows the impinging neutral particles to enter through the shuttering system with a definite timing. Particles are then flown in a ToF chamber, and finally detected by a 1-dimensional array composed by MCPs and a discrete anodes set corresponding to a Field of View (FOV) of 4.5"x76", allowing the reconstruction of both velocity and direction of the incoming events. This poster will present the new results of the ELENA development in the frame of the scientific items, instrument simulation, laboratory activity and testing. In particular, the ELENA input section and shuttering system will be reported (new deflector system, shuttering functionality test, membranes VUV optical proprieties and particle beam interactions).

Introduction of a mutation in the shutter region of antithrombin (Phe77 --> Leu) increases affinity for heparin and decreases thermal stability.

PubMed

Quinsey, Noelene S; Fitton, Hazel L; Coughlin, Paul; Whisstock, James C; Dafforn, Timothy R; Carrell, Robin W; Bottomley, Stephen P; Pike, Robert N

2003-09-02

The shutter region of serpins consists of a number of highly conserved residues that are critical for both stability and function. Several variants of antithrombin with substitutions in this region are unstable and predispose the carrier to thrombosis. Although most mutations in the shutter region investigated to date are deleterious with respect to serpin stability and function, the substitution of Phe51 by Leu in alpha(1)-antitrypsin results in enhanced stability. Here, we have investigated the effects of introducing an analogous mutation into antithrombin (Phe 77 to Leu). The mutation did not affect the kinetics of interaction with proteases. Strikingly, however, the thermostability of the protein was markedly decreased, with the serpin displaying a 13 degrees C decrease in melting temperature as compared to wild-type recombinant antithrombin. Further studies revealed that in contrast to wild-type antithrombin, the mutant adopted the latent (inactive) conformation upon mild heating. Previous studies on shutter region mutations that destabilize antithrombin revealed that such variants possess enhanced affinity for both heparin pentasaccharide and full-length heparin. The N135A/F77L mutant had unchanged affinity for heparin pentasaccharide, but the affinity for full-length heparin was increased. We suggest that the Phe77Leu mutation causes conformational changes around the top of the D-helix in antithrombin, in particular, to the arginine 132 and 133 residues that may mediate additional antithrombin/heparin interactions. This paper also demonstrates that there are major differences between the shutter regions of antithrombin and alpha(1)-antitrypsin since a stabilizing mutation in antitrypsin has the converse effect in antithrombin.

Measurement of Drop Size Distribution and Liquid Water Content in Natural Clouds - Installation and Calibration of Infrared Spectrometer

DTIC Science & Technology

1952-07-01

The chopper has been removed from its case and the motor , shutter, and breaker assembly have been mounted in such a position that the two beams Will...yaao7U v»i uxi Out? VUIUUI ViOCX OUi * •** Mazda lamp is substituted for the giobar» Turning the shutter by hand cam No« 1 is phased so

Nonlocal Position Changes of a Photon Revealed by Quantum Routers.

PubMed

Elitzur, Avshalom C; Cohen, Eliahu; Okamoto, Ryo; Takeuchi, Shigeki

2018-05-16

Since its publication, Aharonov and Vaidman's three-box paradox has undergone three major advances: i). A non-counterfactual scheme by the same authors in 2003 with strong rather than weak measurements for verifying the particle's subtle presence in two boxes. ii) A realization of the latter by Okamoto and Takeuchi in 2016. iii) A dynamic version by Aharonov et al. in 2017, with disappearance and reappearance of the particle. We now combine these advances together. Using photonic quantum routers the particle acts like a quantum "shutter." It is initially split between Boxes A, B and C, the latter located far away from the former two. The shutter particle's whereabouts can then be followed by a probe photon, split in both space and time and reflected by the shutter in its varying locations. Measuring the former is expected to reveal the following time-evolution: The shutter particle was, with certainty, in boxes A+C at t 1 , then only in C at t 2 , and finally in B+C at t 3 . Another branch of the split probe photon can show that boxes A+B were empty at t 2 . A Bell-like theorem applied to this experiment challenges any alternative interpretation that avoids disappearance-reappearance in favor of local hidden variables.

Unique dome design for the SOAR telescope project

NASA Astrophysics Data System (ADS)

Teran, Jose U.; Porter, David S.; Hileman, Edward A.; Neff, Daniel H.

2000-08-01

The SOAR telescope dome is a 20 meter diameter 5/8 spherical structure built on a rotating steel frame with an over the top nesting shutter and covered with a fiberglass panel system. The insulated fiberglass panel system can be self- supporting and is typically used for radomes on ground based tracking systems. The enclosed observing area is ventilated using a down draft ventilation system. The rotating steel frame is comprised of a ring beam and dual arch girders to provide support to the panel system sections and guide the shutter. The dual door shutter incorporates a unique differential drive system that reduces the complexity of the control system. The dome, shutter and windscreen `track' the telescope for maximum wind protection. The dome rotates on sixteen fixed compliant bogie assemblies. The dome is designed for assembly in sections off the facility and lifted into place for minimal impact on assembly of other telescope systems. The expected cost of the complete dome; including structure, drives, and controls is under 1.7 million. The details covered in this paper are the initial trade-offs and rationale required by SOAR to define the dome, the detailed design performed by M3 Engineering and Technology, and the choices made during the design.

Addressable microshutter array for a high-performance infrared miniature dispersive spectrometer

NASA Astrophysics Data System (ADS)

Ilias, S.; Picard, F.; Larouche, C.; Kruzelecky, R.; Jamroz, W.

2009-02-01

Programmable microshutter arrays were designed to improve the attainable signal to noise ratio (SNR) of a miniature dispersive spectrometer developed for space applications. Integration of a microshutter array to this instrument provides advantages such as the addition of a binary coded optical input operation mode for the miniature spectrometer which results in SNR benefits without spectral resolution loss. These arrays were successfully fabricated using surface micromachining technology. Each microshutter is basically an electrostatic zipping actuator having a curved shape. Applying critical voltage to one microshutter pulls the actuator down to the substrate and closes the associated slit. Opening of the microslits relies on the restoring force generated within the actuated zippers. High light transmission is obtained with the actuator in the open position and excellent light blocking is observed when the shutter is closed. The pull-in voltage to close the microslits was about 110 V and the response times to close and open the microslits were about 2 ms and 7 ms, respectively. Selected array dies were mounted in modified off-the-shelf ceramic packages and electrically connected to package pins. The packages were hermetically sealed with AR coated sapphire windows. This last packaging step was performed in a dry nitrogen controlled atmosphere.

Holocamera for 3-D micrography of the alert human eye

NASA Astrophysics Data System (ADS)

Tokuda, A. R.; Auth, D. C.; Bruckner, A. P.

1980-07-01

A holocamera that safely records holograms of the full depth of the alert human eye with a spatial resolution of about 20 microns is described. A single-mode argon-ion laser generating 2 W at 5145 A serves as the illuminating source. Holographic exposure times of 0.3 msec are achieved by means of a fail-safe electromechanical shutter system. Integrated retinal irradiance levels are well under the American National Standards Institute safety standards. Reconstructed real images are projected directly onto the vidicon faceplate of a closed-circuit TV system, enabling convenient scanning in the x-y-z dimensions of the reconstructed eyeball. Serially reconstructed holograms of cataractous rabbit eyes and normal human eyes are presented.

Fiber-Optic Pyrometer with Optically Powered Switch for Temperature Measurements

PubMed Central

Pérez-Prieto, Sandra; López-Cardona, Juan D.; Blanco, Enrique; Moreno-López, Jorge

2018-01-01

We report the experimental results on a new infrared fiber-optic pyrometer for very localized and high-speed temperature measurements ranging from 170 to 530 °C using low-noise photodetectors and high-gain transimpedance amplifiers with a single gain mode in the whole temperature range. We also report a shutter based on an optical fiber switch which is optically powered to provide a reference signal in an optical fiber pyrometer measuring from 200 to 550 °C. The tests show the potential of remotely powering via optical means a 300 mW power-hungry optical switch at a distance of 100 m, avoiding any electromagnetic interference close to the measuring point. PMID:29415477

Fiber-Optic Pyrometer with Optically Powered Switch for Temperature Measurements.

PubMed

Vázquez, Carmen; Pérez-Prieto, Sandra; López-Cardona, Juan D; Tapetado, Alberto; Blanco, Enrique; Moreno-López, Jorge; Montero, David S; Lallana, Pedro C

2018-02-06

We report the experimental results on a new infrared fiber-optic pyrometer for very localized and high-speed temperature measurements ranging from 170 to 530 °C using low-noise photodetectors and high-gain transimpedance amplifiers with a single gain mode in the whole temperature range. We also report a shutter based on an optical fiber switch which is optically powered to provide a reference signal in an optical fiber pyrometer measuring from 200 to 550 °C. The tests show the potential of remotely powering via optical means a 300 mW power-hungry optical switch at a distance of 100 m, avoiding any electromagnetic interference close to the measuring point.

Technical prospects for commercial and residential distribution and utilization of hydrogen

NASA Technical Reports Server (NTRS)

Pangborn, J.; Scott, M.; Sharer, J.

1976-01-01

Various investigators have assumed that hydrogen will be compatible with conventional gas delivery systems and that, with minor modifications, hydrogen can be utilized in existing equipment for heating and cooking. The paper addresses some of the issues of concern in the compatibility of natural gas systems with hydrogen and hydrogen mixtures and identifies areas for which tests, research, or development are appropriate. Requirements to be met by atmospheric burners built for most commercial and residential gas appliances are discussed. Expected modifications to appliances for satisfactory operation with hydrogen are closing the primary air shutters, replacing the burners, adjusting the appliance gas regulator for proper delivery pressure, and possibly replacing the gas regulator or its vent.

Breaking Waves and Microwave Polarimetric Emissivities: Final Report

DTIC Science & Technology

2005-04-11

in designing and evaluating the errors in retrieval algorithms for CMIS. REFERENCES Asher, W.E., T.M. Litchendorf, and K. Phadnis , The effect of...IEEE Trans. Geosci. Rem. Sensing, 33, 85-92, 1995. PEER-REVIEWED PUBLICATIONS Asher, W.E., T.M. Litchendorf and K. Phadnis . "The Effect of Shutter...Alaska, September, 2004. Asher, W.E., T.M. Litchendorf and K. Phadnis , 2004. "The Effect of Shutter Speed on Measuring Size-Segregated Bubble

[Three-dimensional display simulation of lung surgery using "active shutter glasses"].

PubMed

Onuki, Takamasa; Kanzaki, Masato; Sakamoto, Kei; Kikkawa, Takuma; Isaka, Tamami; Shimizu, Toshihide; Oyama, Kunihiro; Murasugi, Masahide

2011-08-01

We have reported preoperative 3-dimensional (3D) simulation of thoracoscopic lung surgery using self-made software and internet shareware of 3D-modeler. Using "active shutter glasses", we have tried the "3D display simulation" of lung surgery. 3D display was more effective to grasp clear 3D interrelation between the bronchii and pulmonary vascular system than those in images of currently in use with the same information volume.

Cryogenic Photogrammetry and Radiometry for the James Webb Space Telescope Microshutters

NASA Technical Reports Server (NTRS)

Chambers, Victor J.; Morey, Peter A.; Zukowski, Barbara J.; Kutyrev, Alexander S.; Collins, Nicholas R.

2012-01-01

The James Webb Space Telescope (JWST) relies on several innovations to complete its five year mission. One vital technology is microshutters, the programmable field selectors that enable the Near Infrared Spectrometer (NIRSpec) to perform multi-object spectroscopy. Mission success depends on acquiring spectra from large numbers of galaxies by positioning shutter slits over faint targets. Precise selection of faint targets requires field selectors that are both high in contrast and stable in position. We have developed test facilities to evaluate microshutter contrast and alignment stability at their 35K operating temperature. These facilities used a novel application of image registration algorithms to obtain non-contact, sub-micron measurements in cryogenic conditions. The cryogenic motion of the shutters was successfully characterized. Optical results also demonstrated that shutter contrast far exceeds the NIRSpec requirements. Our test program has concluded with the delivery of a flight-qualified field selection subsystem to the NIRSpec bench.

Light shift measurements in a Cesium Fountain without the use of mechanical shutters

NASA Technical Reports Server (NTRS)

Tjoelker, Robert L.; Enzer, D. G.; Klipstein, W. M.

2005-01-01

We present measurements confirming operation of a cesium fountain frequency standard with light shift below 10^-15 (and with evidence suggesting it is several orders of magnitude below this level) but without the use of mechanical shutters. Suppression of the light shift is realized using a master-slave laser configuration by reducing the overall optical power delivered to the physics package as well as spoiling the injection of the slave, causing it to lase far off resonance (1-2 nm) as proposed by the authors several years ago [l]. In the absence of any mitigation, this (AC Stark) shift, due to near-resonant laser light reaching the atoms during their microwave interrogation period, is the largest shift in such frequency standards (2x10^-11 for Our fountain). Mechanical shutters provided adequate light attenuation but have been prone to failure.

Decoding mobile-phone image sensor rolling shutter effect for visible light communications

NASA Astrophysics Data System (ADS)

Liu, Yang

2016-01-01

Optical wireless communication (OWC) using visible lights, also known as visible light communication (VLC), has attracted significant attention recently. As the traditional OWC and VLC receivers (Rxs) are based on PIN photo-diode or avalanche photo-diode, deploying the complementary metal-oxide-semiconductor (CMOS) image sensor as the VLC Rx is attractive since nowadays nearly every person has a smart phone with embedded CMOS image sensor. However, deploying the CMOS image sensor as the VLC Rx is challenging. In this work, we propose and demonstrate two simple contrast ratio (CR) enhancement schemes to improve the contrast of the rolling shutter pattern. Then we describe their processing algorithms one by one. The experimental results show that both the proposed CR enhancement schemes can significantly mitigate the high-intensity fluctuations of the rolling shutter pattern and improve the bit-error-rate performance.

Stroboscopic Image Modulation to Reduce the Visual Blur of an Object Being Viewed by an Observer Experiencing Vibration

NASA Technical Reports Server (NTRS)

Kaiser, Mary K. (Inventor); Adelstein, Bernard D. (Inventor); Anderson, Mark R. (Inventor); Beutter, Brent R. (Inventor); Ahumada, Albert J., Jr. (Inventor); McCann, Robert S. (Inventor)

2014-01-01

A method and apparatus for reducing the visual blur of an object being viewed by an observer experiencing vibration. In various embodiments of the present invention, the visual blur is reduced through stroboscopic image modulation (SIM). A SIM device is operated in an alternating "on/off" temporal pattern according to a SIM drive signal (SDS) derived from the vibration being experienced by the observer. A SIM device (controlled by a SIM control system) operates according to the SDS serves to reduce visual blur by "freezing" (or reducing an image's motion to a slow drift) the visual image of the viewed object. In various embodiments, the SIM device is selected from the group consisting of illuminator(s), shutter(s), display control system(s), and combinations of the foregoing (including the use of multiple illuminators, shutters, and display control systems).

NASA Engineers Conduct Low Light Test on New Technology for NASA Webb Telescope

NASA Image and Video Library

2014-09-02

NASA engineers inspect a new piece of technology developed for the James Webb Space Telescope, the micro shutter array, with a low light test at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Developed at Goddard to allow Webb's Near Infrared Spectrograph to obtain spectra of more than 100 objects in the universe simultaneously, the micro shutter array uses thousands of tiny shutters to capture spectra from selected objects of interest in space and block out light from all other sources. Credit: NASA/Goddard/Chris Gunn NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

"The phactalysts": carbon nanotube/TiO2 composites as phototropic actuators for wireless remote triggering of chemical reactions and catalysis.

PubMed

Vassalini, Irene; Alessandri, Ivano

2017-08-17

A new concept of a reconfigurable smart catalyst was developed from the synergistic combination of polycarbonate/carbon nanotube bimorph photoactuators and TiO 2 . The addition of TiO 2 provides the photoactuators with photocatalytic activity and superior opto-mechanical properties, making phototropic actuation fast, reversible and responsive to Vis-NIR light sources. These composites were tested in the wireless, light-driven and spatially controlled remote triggering of different chemical reactions, including local explosions and photocatalytic polymerizations. The same materials were also investigated as efficient opto-mechanical shutters for the light-selective inhibition or activation of specific reactions, such as the photo-induced degradation of organic dyes. These results suggest that the integration of photocatalysts with soft photoactuators can open intriguing opportunities for chemistry and soft robotics.

Comparing light sensitivity, linearity and step response of electronic cameras for ophthalmology.

PubMed

Kopp, O; Markert, S; Tornow, R P

2002-01-01

To develop and test a procedure to measure and compare light sensitivity, linearity and step response of electronic cameras. The pixel value (PV) of digitized images as a function of light intensity (I) was measured. The sensitivity was calculated from the slope of the P(I) function, the linearity was estimated from the correlation coefficient of this function. To measure the step response, a short sequence of images was acquired. During acquisition, a light source was switched on and off using a fast shutter. The resulting PV was calculated for each video field of the sequence. A CCD camera optimized for the near-infrared (IR) spectrum showed the highest sensitivity for both, visible and IR light. There are little differences in linearity. The step response depends on the procedure of integration and read out.

The Role of Near-Fault Relief in Creating and Maintaining Strike-Slip Landscape Features

NASA Astrophysics Data System (ADS)

Harbert, S.; Duvall, A. R.; Tucker, G. E.

2016-12-01

Geomorphic landforms, such as shutter ridges, offset river terraces, and deflected stream channels, are often used to assess the activity and slip rates of strike-slip faults. However, in some systems, such as parts of the Marlborough Fault System (South Island, NZ), an active strike-slip fault does not leave a strong landscape signature. Here we explore the factors that dampen or enhance the landscape signature of strike-slip faulting using the Channel-Hillslope Integrated Landscape Development model (CHILD). We focus on variables affecting the length of channel offsets, which enhance the signature of strike-slip motion, and the frequency of stream captures, which eliminate offsets and reduce this signature. We model a strike-slip fault that passes through a mountain ridge, offsetting streams that drain across this fault. We use this setup to test the response of channel offset length and capture frequency to fault characteristics, such as slip rate and ratio of lateral to vertical motion, and to landscape characteristics, such as relief contrasts controlled by erodibility. Our experiments show that relief downhill of the fault, whether generated by differential uplift across the fault or by an erodibility contrast, has the strongest effect on offset length and capture frequency. This relief creates shutter ridges, which block and divert streams while being advected along a fault. Shutter ridges and the streams they divert have long been recognized as markers of strike-slip motion. Our results show specifically that the height of shutter ridges is most responsible for the degree to which they create long channel offsets by preventing stream captures. We compare these results to landscape metrics in the Marlborough Fault System, where shutter ridges are common and often lithologically controlled. We compare shutter ridge length and height to channel offset length in order to assess the influence of relief on offset channel features in a real landscape. Based on our model and field results, we conclude that vertical relief is important for generating and preserving offset features that are viewed as characteristic of a strike-slip fault. Therefore, the geomorphic expression of a fault may be dependent on characteristics of the surrounding landscape rather than primarily a function of the nature of slip on the fault.

Thin-film optical shutter. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlow, S.L.

1981-02-01

A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

Planning JWST NIRSpec MSA spectroscopy using NIRCam pre-images

NASA Astrophysics Data System (ADS)

Beck, Tracy L.; Ubeda, Leonardo; Kassin, Susan A.; Gilbert, Karoline; Karakla, Diane M.; Reid, I. N.; Blair, William P.; Keyes, Charles D.; Soderblom, D. R.; Peña-Guerrero, Maria A.

2016-07-01

The Near-Infrared Spectrograph (NIRSpec) is the work-horse spectrograph at 1-5microns for the James Webb Space Telescope (JWST). A showcase observing mode of NIRSpec is the multi-object spectroscopy with the Micro-Shutter Arrays (MSAs), which consist of a quarter million tiny configurable shutters that are 0. ''20×0. ''46 in size. The NIRSpec MSA shutters can be opened in adjacent rows to create flexible and positionable spectroscopy slits on prime science targets of interest. Because of the very small shutter width, the NIRSpec MSA spectral data quality will benefit significantly from accurate astrometric knowledge of the positions of planned science sources. Images acquired with the Hubble Space Telescope (HST) have the optimal relative astrometric accuracy for planning NIRSpec observations of 5-10 milli-arcseconds (mas). However, some science fields of interest might have no HST images, galactic fields can have moderate proper motions at the 5mas level or greater, and extragalactic images with HST may have inadequate source information at NIRSpec wavelengths beyond 2 microns. Thus, optimal NIRSpec spectroscopy planning may require pre-imaging observations with the Near-Infrared Camera (NIRCam) on JWST to accurately establish source positions for alignment with the NIRSpec MSAs. We describe operational philosophies and programmatic considerations for acquiring JWST NIRCam pre-image observations for NIRSpec MSA spectroscopic planning within the same JWST observing Cycle.

Analysis of the diffraction effects for a multi-view autostereoscopic three-dimensional display system based on shutter parallax barriers with full resolution

NASA Astrophysics Data System (ADS)

Meng, Yang; Yu, Zhongyuan; Jia, Fangda; Zhang, Chunyu; Wang, Ye; Liu, Yumin; Ye, Han; Chen, Laurence Lujun

2017-10-01

A multi-view autostereoscopic three-dimensional (3D) system is built by using a 2D display screen and a customized parallax-barrier shutter (PBS) screen. The shutter screen is controlled dynamically by address driving matrix circuit and it is placed in front of the display screen at a certain location. The system could achieve densest viewpoints due to its specially optical and geometric design which is based on concept of "eye space". The resolution of 3D imaging is not reduced compared to 2D mode by using limited time division multiplexing technology. The diffraction effects may play an important role in 3D display imaging quality, especially when applied to small screen, such as iPhone screen etc. For small screen, diffraction effects may contribute crosstalk between binocular views, image brightness uniformity etc. Therefore, diffraction effects are analyzed and considered in a one-dimensional shutter screen model of the 3D display, in which the numerical simulation of light from display pixels on display screen through parallax barrier slits to each viewing zone in eye space, is performed. The simulation results provide guidance for criteria screen size over which the impact of diffraction effects are ignorable, and below which diffraction effects must be taken into account. Finally, the simulation results are compared to the corresponding experimental measurements and observation with discussion.

Radiation Test Results for a MEMS Microshutter Operating at 60 K

NASA Technical Reports Server (NTRS)

Rapchun, David A.; Buchner, Stephen; Moseley, Harvey; Meyer, Stephen E.; Ray, Knute; Tuttle, Jim; Quinn, Ed; Buchanan, Ernie; Bloom, Dave; Hait, Tom;

Open- and closed-state fast inactivation in sodium channels

PubMed Central

Lehmann-Horn, Frank; Holzherr, Boris D

2011-01-01

The role of sodium channel closed-state fast inactivation in membrane excitability is not well understood. We compared open- and closed-state fast inactivation, and the gating charge immobilized during these transitions, in skeletal muscle channel hNaV1.4. A significant fraction of total charge movement and its immobilization occurred in the absence of channel opening. Simulated action potentials in skeletal muscle fibers were attenuated when pre-conditioned by subthreshold depolarization. Anthopleurin A, a site-3 toxin that inhibits gating charge associated with the movement of DIVS4, was used to assess the role of this voltage sensor in closed-state fast inactivation. Anthopleurin elicited opposing effects on the gating mode, kinetics and charge immobilized during open- versus closed-state fast inactivation. This same toxin produced identical effects on recovery of channel availability and remobilization of gating charge, irrespective of route of entry into fast inactivation. Our findings suggest that depolarization promoting entry into fast inactivation from open versus closed states provides access to the IFMT receptor via different rate-limiting conformational translocations of DIVS4. PMID:21099342

VirtoScan - a mobile, low-cost photogrammetry setup for fast post-mortem 3D full-body documentations in x-ray computed tomography and autopsy suites.

PubMed

Kottner, Sören; Ebert, Lars C; Ampanozi, Garyfalia; Braun, Marcel; Thali, Michael J; Gascho, Dominic

2017-03-01

Injuries such as bite marks or boot prints can leave distinct patterns on the body's surface and can be used for 3D reconstructions. Although various systems for 3D surface imaging have been introduced in the forensic field, most techniques are both cost-intensive and time-consuming. In this article, we present the VirtoScan, a mobile, multi-camera rig based on close-range photogrammetry. The system can be integrated into automated PMCT scanning procedures or used manually together with lifting carts, autopsy tables and examination couch. The VirtoScan is based on a moveable frame that carries 7 digital single-lens reflex cameras. A remote control is attached to each camera and allows the simultaneous triggering of the shutter release of all cameras. Data acquisition in combination with the PMCT scanning procedures took 3:34 min for the 3D surface documentation of one side of the body compared to 20:20 min of acquisition time when using our in-house standard. A surface model comparison between the high resolution output from our in-house standard and a high resolution model from the multi-camera rig showed a mean surface deviation of 0.36 mm for the whole body scan and 0.13 mm for a second comparison of a detailed section of the scan. The use of the multi-camera rig reduces the acquisition time for whole-body surface documentations in medico-legal examinations and provides a low-cost 3D surface scanning alternative for forensic investigations.

Efficient demodulation scheme for rolling-shutter-patterning of CMOS image sensor based visible light communications.

PubMed

Chen, Chia-Wei; Chow, Chi-Wai; Liu, Yang; Yeh, Chien-Hung

2017-10-02

Recently even the low-end mobile-phones are equipped with a high-resolution complementary-metal-oxide-semiconductor (CMOS) image sensor. This motivates using a CMOS image sensor for visible light communication (VLC). Here we propose and demonstrate an efficient demodulation scheme to synchronize and demodulate the rolling shutter pattern in image sensor based VLC. The implementation algorithm is discussed. The bit-error-rate (BER) performance and processing latency are evaluated and compared with other thresholding schemes.

Flash protection controller

DOEpatents

Galbraith, L.K.

1979-12-07

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

Flash protection controller

DOEpatents

Galbraith, Lee K.

1981-01-01

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

Electronic imaging system and technique

DOEpatents

Bolstad, J.O.

1984-06-12

A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

Electronic imaging system and technique

DOEpatents

Bolstad, Jon O.

1987-01-01

A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

Process for Making a Semiconductor Device with Barrier Film Formation Using a Metal Halide and Products Thereof

DTIC Science & Technology

1998-08-20

structure of the barrier film on an atomic level where the barrier film is comprised of a plurality of contiguous monolayers, while FIG. 7B shows...another embodiment where the barrier film is comprised of a plurality of i contiguous monolayers in which different monolayers thereof are formed... effusion cell, for example a barium fluoride, strontium fluoride or the like effusion cell, is provided at 32, and has a shutter 33. A 15 shutter 35

Electronic Flash In Data Acquisition

NASA Astrophysics Data System (ADS)

Miller, C. E.

1982-02-01

Photographic acquisition of data often may be simplified, or the data quality improved upon by employing electronic flash sources with traditional equipment or techniques. The relatively short flash duration compared to movie camera shutters, or to the long integration time of video camera provides improved spatial resolution through blur reduction, particularly important as image movement becomes a significant fraction of film format dimension. Greater accuracy typically is achieved in velocity and acceleration determinations by using a stroboscopic light source rather than a movie camera frame-rate control as a time standard. Electrical efficiency often is an important advantage of electronic flash sources since almost any necessary light level for exposure may be produced, yet the source typically is "off" most of the time. Various synchronization techniques greatly expand the precise control of exposure. Biomechanical and sports equipment studies may involve velocities up to 200 feet-per-second, and often will have associated very rapid actions of interest. The need for brief exposures increases H.s one "ZOOMS in on the action." In golf, for example, the swing may be examined using 100 microsecond (Us) flashes at rates of 60 or 120 flashes-per-second (FPS). Accurate determination of linear and rotational velocity of the ball requires 10 Us flashes at 500-1,000 FPS, while sub-Us flashes at 20,000-50,000 FPS are required to resolve the interaction of the ball and the club, head. Some seldom. used techniques involving streak photography are described, with enhanced results obtained by combining strobe with the usual continuous light source. The combination of strobe and a fast electro-mechanical shutter is considered for Us photography under daylight conditions.

Development of a pepper pot emittance probe and its application for ECR ion beam studies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondrashev, S.; Barcikowski, A.; Mustapha, B.

2009-07-21

A pepper pot-scintillator screen system has been developed and used to measure the emittance of DC ion beams extracted from a high-intensity permanent magnet ECR ion source. The system includes a fast beam shutter with a minimum dwell time of 18 ms to reduce the degradation of the CsI(Tl) scintillator by DC ion beam irradiation and a CCD camera with a variable shutter speed in the range of 1 {micro}s-65 s. On-line emittance measurements are performed by an application code developed on a LabVIEW platform. The sensitivity of the device is sufficient to measure the emittance of DC ion beamsmore » with current densities down to about 100 nA/cm{sup 2}. The emittance of all ion species extracted from the ECR ion source and post-accelerated to an energy of 75-90 keV/charge have been measured downstream of the LEBT. As the mass-to-charge ratio of ion species increases, the normalized RMS emittances in both transverse phase planes decrease from 0.5-1.0 {pi} mm mrad for light ions to 0.05-0.09 {pi} mm mrad for highly charged {sup 209}Bi ions. The dependence of the emittance on ion's mass-to-charge ratio follows very well the dependence expected from beam rotation induced by decreasing ECR axial magnetic field. The measured emittance values cannot be explained by only ion beam rotation for all ion species and the contribution to emittance of ion temperature in plasma, non-linear electric fields and non-linear space charge is comparable or even higher than the contribution of ion beam rotation.« less

HIGH SPEED KERR CELL FRAMING CAMERA

DOEpatents

Goss, W.C.; Gilley, L.F.

1964-01-01

The present invention relates to a high speed camera utilizing a Kerr cell shutter and a novel optical delay system having no moving parts. The camera can selectively photograph at least 6 frames within 9 x 10/sup -8/ seconds during any such time interval of an occurring event. The invention utilizes particularly an optical system which views and transmits 6 images of an event to a multi-channeled optical delay relay system. The delay relay system has optical paths of successively increased length in whole multiples of the first channel optical path length, into which optical paths the 6 images are transmitted. The successively delayed images are accepted from the exit of the delay relay system by an optical image focusing means, which in turn directs the images into a Kerr cell shutter disposed to intercept the image paths. A camera is disposed to simultaneously view and record the 6 images during a single exposure of the Kerr cell shutter. (AEC)

Modifying a Rodenstock scanning laser ophthalmoscope for imaging densitometry.

PubMed

Tornow, R P; Beuel, S; Zrenner, E

1997-08-01

The necessary modifications and technical requirements are described for using a commercially available scanning laser ophthalmoscope (Rodenstock Model 101 SLO) as an imaging densitometer to assess human photopigment distribution. The main requirements are a linear detector amplifier, fast shutters for the laser beams, and a trigger unit. Images must be compensated for varying laser intensity. Both rod and cone photopigments are measured with the 514-nm argon laser of the SLO. Discrimination is possible owing to the different spatial distribution. The cone pigment density peaks in the foveal center (D = 0.40) with a steep decrease with increasing eccentricity E (full width at half-maximum, 2.5 degrees ). Rod photopigment increases with increasing eccentricity (D = 0.23 for E = 11 degrees ). These values are in agreement with previous reported results obtained with scanning laser ophthalmoscopes specially designed for retinal densitometry and high stability.

A laser based frequency modulated NL-OSL phenomenon

NASA Astrophysics Data System (ADS)

Mishra, D. R.; Bishnoi, A. S.; Soni, Anuj; Rawat, N. S.; Bhatt, B. C.; Kulkarni, M. S.; Babu, D. A. R.

2015-01-01

The detailed theoretical and experimental approach to novel technique of pulse frequency modulated stimulation (PFMS) method has been described for NL-OSL phenomenon. This method involved pulsed frequency modulation with respect to time for fixed pulse width of 532 nm continuous wave (CW)-laser light. The linearly modulated (LM)-, non-linearly (NL)-stimulation profiles have been generated using fast electromagnetic optical shutter. The PFMS parameters have been determined for present experimental setup. The PFMS based LM-, NL-OSL studies have been carried out on dosimetry grade single crystal α-Al2O3:C. The photo ionization cross section of α-Al2O3:C has been found to be ∼9.97 × 10-19 cm2 for 532 nm laser light using PFMS LM-OSL studies under assumption of first order of kinetic. This method of PFMS is found to be a potential alternative to generate different stimulation profiles using CW-light sources.

Motion compensation for structured light sensors

NASA Astrophysics Data System (ADS)

Biswas, Debjani; Mertz, Christoph

2015-05-01

In order for structured light methods to work outside, the strong background from the sun needs to be suppressed. This can be done with bandpass filters, fast shutters, and background subtraction. In general this last method necessitates the sensor system to be stationary during data taking. The contribution of this paper is a method to compensate for the motion if the system is moving. The key idea is to use video stabilization techniques that work even if the illuminator is switched on and off from one frame to another. We used OpenCV functions and modules to implement a robust and efficient method. We evaluated it under various conditions and tested it on a moving robot outdoors. We will demonstrate that one can not only do 3D reconstruction under strong ambient light, but that it is also possible to observe optical properties of the objects in the environment.

Visible light communication based vehicle positioning using LED street light and rolling shutter CMOS sensors

NASA Astrophysics Data System (ADS)

Do, Trong Hop; Yoo, Myungsik

2018-01-01

This paper proposes a vehicle positioning system using LED street lights and two rolling shutter CMOS sensor cameras. In this system, identification codes for the LED street lights are transmitted to camera-equipped vehicles through a visible light communication (VLC) channel. Given that the camera parameters are known, the positions of the vehicles are determined based on the geometric relationship between the coordinates of the LEDs in the images and their real world coordinates, which are obtained through the LED identification codes. The main contributions of the paper are twofold. First, the collinear arrangement of the LED street lights makes traditional camera-based positioning algorithms fail to determine the position of the vehicles. In this paper, an algorithm is proposed to fuse data received from the two cameras attached to the vehicles in order to solve the collinearity problem of the LEDs. Second, the rolling shutter mechanism of the CMOS sensors combined with the movement of the vehicles creates image artifacts that may severely degrade the positioning accuracy. This paper also proposes a method to compensate for the rolling shutter artifact, and a high positioning accuracy can be achieved even when the vehicle is moving at high speeds. The performance of the proposed positioning system corresponding to different system parameters is examined by conducting Matlab simulations. Small-scale experiments are also conducted to study the performance of the proposed algorithm in real applications.

Accelerator Vacuum Protection System

NASA Astrophysics Data System (ADS)

Barua, Pradip; Kothari, Ashok; Archunan, M.; Joshi, Rajan

2012-11-01

A new and elaborate automatic vacuum protection system using fast acting valve has been installed to avoid accidental venting of accelerator from experimental chamber side. To cover all the beam lines and to reduce the system cost, it has been installed at a common point from where all the seven beam lines originate. The signals are obtained by placing fast response pressure sensing gauges (HV SENSOR) near all the experimental stations. The closing time of the fast valve is 10 milli-second. The fast closing system protects only one vacuum line at a time. At IUAC, we have seven beam lines so one sensor was placed in each of the beam lines near experimental chamber and a multiplexer was incorporated into the fast closing system. At the time of experiment, the sensor of the active beam line is selected through the multiplexer and the Fast closing valve is interlocked with the selected sensor. As soon as the pressure sensor senses the pressure rise beyond a selected pressure, the signal is transferred and the fast valve closes within 10 to 12 millisecond.

Molecular Dynamics Underlie the Nature of MRI Signals: The NMR Shutter-Speed

NASA Astrophysics Data System (ADS)

Springer, Charles S., Jr.

2007-03-01

Motions of the spin-bearing molecules can have profound effects on the very nature (the exponentiality) of the macroscopic NMR signal. Quantitative mechanistic protocols often involve varying the equilibrium molecular kinetics (usually by temperature change) relative to the ``NMR time-scale'' (SS-1), usually ill-defined as the absolute difference of resonance frequencies [|δφ|] in sites between which spins are exchanged. This holds true for the equilibrium water molecule exchange between tissue compartments and distinct populations. However, in vivo studies must [by regulation] be isothermal, and the tissue ^1H2O MRI signals remain essentially isochronous [δφ = 0]. In NMR, an equilibrium process is manifest in the context of its ``exchange condition.'' It only ``appears'' to be fast or slow by comparison of its actual rate constant with its system ``shutter-speed'' (SS). [A nonzero δφ is the first, but not only, SS: its dimension is reciprocal time.] The process kinetics can be measured only if its NMR condition is varied at least partway between the fast- and slow exchange limits. In an isothermal study with no catalyst, this can be accomplished only by varying the pertinent SS. An MRI contrast reagent (CR) increases the laboratory frame ^1H2O relaxation rate constant, Ri [≡ (Ti)-1; i = 1,2]. For an isochronous exchange process, the SS is the intrinsic |δRi| for the sites. In quantitative dynamic-contrast-enhanced (DCE) studies, analytical pharmacokinetic modeling is accomplished on region-of-interest (ROI) or pixel by pixel ^1H2O signal time-courses following bolus CR injections. Accounting for the equilibrium transendothelial and transcytolemmal water interchange processes (a three-site exchange situation) is crucial for modeling accuracy: the relevant SS values vary during the CR bolus passage. This is so for DCE studies of cancer, multiple sclerosis, and myocardial blood flow variation. It is necessary for the successful discrimination of malignant and benign breast and prostate lesions. One can expect a SS for almost any NMR experiment. This includes diffusion weighted and rotating-frame longitudinal relaxation of in vivo ^1H2O signals. In these latter cases, the pertinent SS can be manipulated solely by adjustment of pulse sequence parameters, leading to completely non-invasive protocols.

Comparison of built environment adaptations to heat exposure and mortality during hot weather, West Midlands region, UK.

PubMed

Taylor, Jonathon; Wilkinson, Paul; Picetti, Roberto; Symonds, Phil; Heaviside, Clare; Macintyre, Helen L; Davies, Michael; Mavrogianni, Anna; Hutchinson, Emma

2018-02-01

There is growing recognition of the need to improve protection against the adverse health effects of hot weather in the context of climate change. We quantify the impact of the Urban Heat Island (UHI) and selected adaptation measures made to dwellings on temperature exposure and mortality in the West Midlands region of the UK. We used 1) building physics models to assess indoor temperatures, initially in the existing housing stock and then following adaptation measures (energy efficiency building fabric upgrades and/or window shutters), of representative dwelling archetypes using data from the English Housing Survey (EHS), and 2) modelled UHI effect on outdoor temperatures. The ages of residents were combined with evidence on the heat-mortality relationship to estimate mortality risk and to quantify population-level changes in risk following adaptations to reduce summertime heat exposure. Results indicate that the UHI effect accounts for an estimated 21% of mortality. External shutters may reduce heat-related mortality by 30-60% depending on weather conditions, while shutters in conjunction with energy-efficient retrofitting may reduce risk by up to 52%. The use of shutters appears to be one of the most effective measures providing protection against heat-related mortality during periods of high summer temperatures, although their effectiveness may be limited under extreme temperatures. Energy efficiency adaptations to the dwellings and measures to increase green space in the urban environment to combat the UHI effect appear to be less beneficial for reducing heat-related mortality. Copyright © 2017 Elsevier Ltd. All rights reserved.

DCS - A high flux beamline for time resolved dynamic compression science – Design highlights

DOE PAGES

Capatina, D.; D’Amico, K.; Nudell, J.; ...

2016-07-27

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures.more » Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm 2. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm 2. Finally, a new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.« less

DCS - A high flux beamline for time resolved dynamic compression science – Design highlights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capatina, D., E-mail: capatina@aps.anl.gov; D’Amico, K., E-mail: kdamico@aps.anl.gov; Nudell, J., E-mail: jnudell@aps.anl.gov

2016-07-27

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures.more » Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm{sup 2}. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm{sup 2}. A new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.« less

DCS - A High Flux Beamline for Time Resolved Dynamic Compression Science – Design Highlights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capatina, D.; D'Amico, Kevin L.; Nudell, J.

2016-07-27

The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures.more » Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm2. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm2. A new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.« less

Response of Metal Core Piezoelectric Fibers to Unsteady Airflows

NASA Astrophysics Data System (ADS)

Qiu, J. H.; Ji, H. L.; Zhu, K. J.; Park, M. J.

In the previous study, possible applications of metal core piezoelectric fibers with a diameter of 200 to 250 µm as bionic airflow sensors mimicking the flow sensitive receptor hairs of crickets have been proposed. This study aims to investigate the dynamic responses of the metal core piezoelectric fibers to unsteady airflow. The metal core piezoelectric fiber is half coated on the outer surface and is used in the bending mode. Wind tunnel tests were carried out and the output voltage of the fiber under the excitation of the unsteady aerodynamic force during flow acceleration and deceleration was measured when the wind tunnel was suddenly closed or opened by a shutter. The relationship between the maximum voltage and the steady-state velocity and that between the voltage and the acceleration of flow were also obtained.

Low energy high angular resolution neutral atom detection by means of micro-shuttering techniques: the BepiColombo SERENA/ELENA sensor

NASA Astrophysics Data System (ADS)

Orsini, S.; di Lellis, A. M.; Milillo, A.; de Angelis, E.; Mura, A.; Selci, S.; Dandouras, I.; Cerulli-Irelli, P.; Leoni, R.; Mangano, V.; Massetti, S.; Mattioli, F.; Orfei, R.; Austin, C.; Medale, J.-L.; Vertolli, N.; di Giulio, D.

2009-06-01

The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E~20 eV up to E~5 keV, within 1-D (2°×76°). ELENA is a Time-of-Flight (TOF) system, based on oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical gratings: the incoming neutral particles directly impinge upon the entrance with a definite timing (START) and arrive to a STOP detector after a flight path. After a brief dissertation on the achievable scientific objectives, this paper describes the instrument, with the new design techniques approached for the neutral particles identification and the nano-techniques used for designing and manufacturing the nano-structure shuttering core of the ELENA sensor. The expected count-rates, based on the Hermean environment features, are shortly presented and discussed. Such design technologies could be fruitfully exported to different applications for planetary exploration.

Shutter heating system of Antarctic bright star survey telescope

NASA Astrophysics Data System (ADS)

Chen, Jie; Dong, Shucheng; Jiang, Fengxin; Zhang, Hongfei; Wang, Jian

2016-07-01

A heat preservation system for mechanical shutter in Antarctic is introduced in the paper. The system consists of the heat preservation chamber, the host controller STM32F103C8T6 with peripheral circuit and the control algorithm. The whole design is carried out on the basis of the low temperature requirement, including the cavity structure and thermal insulation. The heat preservation chamber is used to keep the shutter warm and support the weight of the camera. Using PT100 as the temperature sensor, the signal processing circuit converts the temperature to the voltage which is then digitized by the 12 bit ADC in the STM32. The host controller transforms the voltage data into temperature, and through the tuning of the Fussy PID algorithm which controls the duty cycle of the MOSFET, the temperature control of chamber is realized. The System has been tested in the cryogenic environment for a long time, with characteristic of low temperature resistance, small volume, high accuracy of temperature control as well as remote control and detection.

Research on a dem Coregistration Method Based on the SAR Imaging Geometry

NASA Astrophysics Data System (ADS)

Niu, Y.; Zhao, C.; Zhang, J.; Wang, L.; Li, B.; Fan, L.

2018-04-01

Due to the systematic error, especially the horizontal deviation that exists in the multi-source, multi-temporal DEMs (Digital Elevation Models), a method for high precision coregistration is needed. This paper presents a new fast DEM coregistration method based on a given SAR (Synthetic Aperture Radar) imaging geometry to overcome the divergence and time-consuming problem of the conventional DEM coregistration method. First, intensity images are simulated for two DEMs under the given SAR imaging geometry. 2D (Two-dimensional) offsets are estimated in the frequency domain using the intensity cross-correlation operation in the FFT (Fast Fourier Transform) tool, which can greatly accelerate the calculation process. Next, the transformation function between two DEMs is achieved via the robust least-square fitting of 2D polynomial operation. Accordingly, two DEMs can be precisely coregistered. Last, two DEMs, i.e., one high-resolution LiDAR (Light Detection and Ranging) DEM and one low-resolution SRTM (Shutter Radar Topography Mission) DEM, covering the Yangjiao landslide region of Chongqing are taken as an example to test the new method. The results indicate that, in most cases, this new method can achieve not only a result as much as 80 times faster than the minimum elevation difference (Least Z-difference, LZD) DEM registration method, but also more accurate and more reliable results.

Delayed Shutters For Dual-Beam Molecular Epitaxy

NASA Technical Reports Server (NTRS)

Grunthaner, Frank J.; Liu, John L.; Hancock, Bruce

1989-01-01

System of shutters for dual-molecular-beam epitaxy apparatus delays start of one beam with respect to another. Used in pulsed-beam equipment for deposition of low-dislocation layers of InAs on GaAs substrates, system delays application of arsenic beam with respect to indium beam to assure proper stoichiometric proportions on newly forming InAs surface. Reflectance high-energy electron diffraction (RHEED) instrument used to monitor condition of evolving surface of deposit. RHEED signal used to time pulsing of molecular beams in way that minimizes density of defects and holds lattice constant of InAs to that of GaAs substrate.

Controlled environment vitrification system for preparation of liquids

DOEpatents

Bellare, Jayesh R.; Davis, Howard T.; Scriven, II, L. Edward; Talmon, Yeshayahu

1988-01-01

A system for preparing specimens in a controlled environment to insure that a liquid or partially liquid specimen is maintained in its original state while it is being prepared, and once prepared the specimen is vitrified or solidified with minimal alteration of its microstructure. The controlled environment is provided within a chamber where humidity and temperature can be controlled precisely while the specimen is prepared. The specimen is mounted on a plunger and a shutter controlled opening is opened substantially simultaneously with release of the plunger so the specimen is propelled through the shutter into an adjacent cryogenic bath.

Controlled environment vitrification system for preparation of liquids

DOEpatents

Bellare, J.R.; Davis, H.T.; Scriven, L.E. II; Talmon, Y.

1988-06-28

A system is described for preparing specimens in a controlled environment to insure that a liquid or partially liquid specimen is maintained in its original state while it is being prepared, and once prepared the specimen is vitrified or solidified with minimal alteration of its microstructure. The controlled environment is provided within a chamber where humidity and temperature can be controlled precisely while the specimen is prepared. The specimen is mounted on a plunger and a shutter controlled opening is opened substantially simultaneously with release of the plunger so the specimen is propelled through the shutter into an adjacent cryogenic bath. 7 figs.

Irradiation Testing Vehicles for Fast Reactors from Open Test Assemblies to Closed Loops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sienicki, James J.; Grandy, Christopher

A review of irradiation testing vehicle approaches and designs that have been incorporated into past Sodium-Cooled Fast Reactors (SFRs) or envisioned for incorporation has been carried out. The objective is to understand the essential features of the approaches and designs so that they can inform test vehicle designs for a future U.S. Fast Test Reactor. Fast test reactor designs examined include EBR-II, FFTF, JOYO, BOR-60, PHÉNIX, JHR, and MBIR. Previous designers exhibited great ingenuity in overcoming design and operational challenges especially when the original reactor plant’s mission changed to an irradiation testing mission as in the EBRII reactor plant. Themore » various irradiation testing vehicles can be categorized as: Uninstrumented open assemblies that fit into core locations; Instrumented open test assemblies that fit into special core locations; Self-contained closed loops; and External closed loops. A special emphasis is devoted to closed loops as they are regarded as a very desirable feature of a future U.S. Fast Test Reactor. Closed loops are an important technology for irradiation of fuels and materials in separate controlled environments. The impact of closed loops on the design of fast reactors is also discussed in this report.« less

First measurements of Dα spectrum produced by anisotropic fast ions in the gas dynamic trap

NASA Astrophysics Data System (ADS)

Lizunov, A.; Anikeev, A.

2014-11-01

Angled injection of eight deuterium beams in gas dynamic trap (GDT) plasmas builds up the population of fast ions with the distribution function, which conserves a high degree of initial anisotropy in space, energy, and pitch angle. Unlike the Maxwellian distribution case, the fast ion plasma component in GDT cannot be exhaustively characterized by the temperature and density. The instrumentation complex to study of fast ions is comprised of motional Stark effect diagnostic, analyzers of charge exchange atoms, and others. The set of numerical codes using for equilibrium modeling is also an important tool of analysis. In the recent campaign of summer 2014, we recorded first signals from the new fast ion D-alpha diagnostic on GDT. This paper presents the diagnostic description and results of pilot measurements. The diagnostic has four lines of sight, distributed across the radius of an axially symmetric plasma column in GDT. In the present setup, a line-integrated optical signal is measured in each channel. In the transverse direction, the spatial resolution is 18 mm. Collected light comes to the grating spectrometer with the low-noise detector based on a charge-coupled device matrix. In the regime of four spectra stacked vertically on the sensor, the effective spectral resolution of measurements is approximately 0.015 nm. Exposure timing is provided by the fast optical ferroelectric crystal shutter, allowing frames of duration down to 70 μs. This number represents the time resolution of measurements. A large dynamic range of the camera permits for a measurement of relatively small light signals produced by fast ions on top of the bright background emission from the bulk plasma. The fast ion emission has a non-Gaussian spectrum featuring the characteristic width of approximately 4 nm, which can be separated from relatively narrow Gaussian lines of D-alpha and H-alpha coming from the plasma periphery, and diagnostic beam emission. The signal to noise ratio varies from approximately ten for the central channel to approximately five for the outermost channel. We used the special set of Monte Carlo codes to fit the measured spectra. The shape of model fit shows a good agreement with the experimental fast ion D-alpha spectrum.

Surface segregation effects of erbium in GaAs growth and their implications for optical devices containing ErAs nanostructures

NASA Astrophysics Data System (ADS)

Crook, Adam M.; Nair, Hari P.; Bank, Seth R.

2011-03-01

We report on the integration of semimetallic ErAs nanoparticles with high optical quality GaAs-based semiconductors, grown by molecular beam epitaxy. Secondary ion mass spectrometry and photoluminescence measurements provide evidence of surface segregation and incorporation of erbium into layers grown with the erbium cell hot, despite the closed erbium source shutter. We establish the existence of a critical areal density of the surface erbium layer, below which the formation of ErAs precipitates is suppressed. Based upon these findings, we demonstrate a method for overgrowing ErAs nanoparticles with III-V layers of high optical quality, using subsurface ErAs nanoparticles as a sink to deplete the surface erbium concentration. This approach provides a path toward realizing optical devices based on plasmonic effects in an epitaxially-compatible semimetal/semiconductor system.

Novel optical switch with a reconfigurable dielectric liquid droplet.

PubMed

Ren, Hongwen; Xu, Su; Ren, Daqiu; Wu, Shin-Tson

2011-01-31

We demonstrated a novel optical switch with a reconfigurable dielectric liquid droplet. The device consists of a clear liquid droplet (glycerol) surrounded by a black liquid (dye-doped liquid crystal). In the voltage-off state, the incident light passing through the clear liquid droplet is absorbed by the black liquid, resulting in a dark state. In the voltage-on state, the dome of the clear liquid droplet is uplifted by the dielectric force to form a light pipe which in turn transmits the incident light. Upon removing the voltage, the droplet recovers to its original shape and the switch is closed. We also demonstrated a red color light switch with ~10:1 contrast ratio and ~300 ms response time. Devices based on such an operation mechanism will find attractive applications in light shutter, tunable iris, variable optical attenuators, and displays.

Performance evaluation of stereo endoscopic imaging system incorporating TFT-LCD.

PubMed

Song, C-G; Park, S-K

2005-01-01

This paper presents a 3D endoscopic video system designed to improve visualization and enhance the ability of the surgeon to perform delicate endoscopic surgery. In a comparison of the polarized and electric shutter-type stereo imaging systems, the former was found to be superior in terms of both accuracy and speed for knot-tying and for the loop pass test. The results of our experiments show that the proposed 3D endoscopic system has a sufficiently wide viewing angle and zone for multi-viewing, and that it provides better image quality and more stable optical performance compared with the electric shutter-type.

Phase elements by means of a photolithographic system employing a spatial light modulator

NASA Astrophysics Data System (ADS)

Aubrecht, Ivo; Miler, Miroslav; Pala, Jan

2003-07-01

The system employs a spatial light modulator (SLM), between a pair of crossed polarizers, and an electronic shutter. Transmission of the SLM with the polarizers is controlled by graphical software that defines which pixels are fully transparent and which are fully opaque. While a particular binary graphics is on the SLM the electronic shutter allows light to pass for a certain time. The graphics is imaged, by an objective, onto a photoresist plate. A mercury lamp is used as a light source. The graphics changes after each exposition and the whole sequence of images determines the resultant surface-relief modulation.

Single-event transient imaging with an ultra-high-speed temporally compressive multi-aperture CMOS image sensor.

PubMed

Mochizuki, Futa; Kagawa, Keiichiro; Okihara, Shin-ichiro; Seo, Min-Woong; Zhang, Bo; Takasawa, Taishi; Yasutomi, Keita; Kawahito, Shoji

2016-02-22

In the work described in this paper, an image reproduction scheme with an ultra-high-speed temporally compressive multi-aperture CMOS image sensor was demonstrated. The sensor captures an object by compressing a sequence of images with focal-plane temporally random-coded shutters, followed by reconstruction of time-resolved images. Because signals are modulated pixel-by-pixel during capturing, the maximum frame rate is defined only by the charge transfer speed and can thus be higher than those of conventional ultra-high-speed cameras. The frame rate and optical efficiency of the multi-aperture scheme are discussed. To demonstrate the proposed imaging method, a 5×3 multi-aperture image sensor was fabricated. The average rising and falling times of the shutters were 1.53 ns and 1.69 ns, respectively. The maximum skew among the shutters was 3 ns. The sensor observed plasma emission by compressing it to 15 frames, and a series of 32 images at 200 Mfps was reconstructed. In the experiment, by correcting disparities and considering temporal pixel responses, artifacts in the reconstructed images were reduced. An improvement in PSNR from 25.8 dB to 30.8 dB was confirmed in simulations.

Walory kulturowe Krainy Otwartych Okiennic

NASA Astrophysics Data System (ADS)

Matus, Irena

2009-01-01

The Open Shutters Land is an ethnographic-tourist project realizing in the territory of three villages in the north-east part of Poland. The shape of two of those villages (Soce and Trześcianka) as royal villages was created during włóka measurement in the 16th century. However Puchły was a private village. The aim of this project is to save wooden, unique, richly ornamented folk building industry. That enterprise came into being in the interwar period and was continued in the post-war period. Characteristic style of houses' decoration: geometric decorated shutters, subtle fretted label moulds, under-windows, boards corners sheltered, wind-protector are typical of that Land. Decorative shuttered timbered gables were graced. Street village ribbon development was built mainly gables to the street, whereas other inventory buildings were done in that same line. Two parish Orthodox churches, wooden, decorated in chisel style in Trześcianka and Puchły villages, a cemetery chapel in Trześcianka, two shrines nearby Soce and Trześcianka, interesting plague and intent crosses as well as original pillar shrines are worth seeing. Moreover, the Narew river, its inflow Rudnia and forests surrounding the villages exalt attraction of that terrain.

Growth and Properties of Lattice Matched GaAsSbN Epilayer on GaAs for Solar Cell Applications

NASA Technical Reports Server (NTRS)

Bharatan, Sudhakar; Iyer, Shanthi; Matney, Kevin; Collis, Ward J.; Nunna Kalyan; Li, Jia; Wu, Liangjin; McGuire, Kristopher; McNeil, Laurie E.

2006-01-01

The growth and properties of GaAsSbN single quantum wells (SQWs) are investigated in this work. The heterostructures were grown on GaAs substrates in an elemental solid source molecular beam epitaxy (MBE) system assisted with a RF plasma nitrogen source. A systematic study has been carried out to determine the influence of various growth conditions, such as the growth temperature and the source shutter-opening sequence, on the quality of the grown layers and the incorporation of N and Sb. The effects of ex situ and in situ annealing under As overpressure on the optical properties of the layers have also been investigated. Substrate temperature in the range of 450-470 C was found to be optimum. Simultaneous opening of the source shutters was found to yield sharper QW interfaces. N and Sb incorporations were found to depend strongly upon substrate temperatures and source shutter opening sequences. A significant increase in PL intensity with a narrowing of PL line shape and blue shift in emission energy were observed on annealing the GaAsSbN/GaAs SQW, with in situ annealing under As overpressure providing better results, compared to ex situ annealing.

Characterization of the ePix100 prototype: a front-end ASIC for second-generation LCLS integrating hybrid pixel detectors

NASA Astrophysics Data System (ADS)

Caragiulo, P.; Dragone, A.; Markovic, B.; Herbst, R.; Nishimura, K.; Reese, B.; Herrmann, S.; Hart, P.; Blaj, G.; Segal, J.; Tomada, A.; Hasi, J.; Carini, G.; Kenney, C.; Haller, G.

2014-09-01

ePix100 is the first variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. ePix100 is optimized for ultra-low noise application requiring high spatial resolution. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per column. The ePix100 variant has 50μmx50μm pixels arranged in a 352x384 matrix, a resolution of 50e- r.m.s. and a signal range of 35fC (100 photons at 8keV). In its final version it will be able to sustain a frame rate of 1kHz. A first prototype has been fabricated and characterized and the measurement results are reported here.

Fast pulsed operation of a small non-radioactive electron source with continuous emission current control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochems, P.; Kirk, A. T.; Bunert, E.

Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron currentmore » due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.« less

Nano- and picosecond 3 μm Er: YSGG lasers using InAs as passive Q-switchers and mode-lockers

NASA Astrophysics Data System (ADS)

Vodopyanov, K. L.; Lukashev, A. V.; Phillips, C. C.

1993-01-01

Recent results are reported using ultra-thin molecular beam epitaxy (MBE)-grown InAs epilayers on GaAs substrates as passive shutters for 3 μm Er: YSGG lasers ( λ = 2.8 μm). The laser photon energy is 27% higher than the InAs bandgap at 300 K and bleaching occurs due to a band filling effect with a fast recovery time of < 100 ps. Depending on the resonator geometry two modes of operation can be achieved: Q-switched with pulse duration of 35 ns and 5-6 mJ energy (TEM 00 mode) and a Q-switched/mode-locked regime with an output in the form of a train of 30 pulses separated by a 4.3 ns interval, 0.25 mJ energy per spike and 30-50 ps pulse duration in a TEM 00-mode. The latter are the shortest pulses obtained with this lasing medium to date.

ePix: a class of architectures for second generation LCLS cameras

DOE PAGES

Dragone, A.; Caragiulo, P.; Markovic, B.; ...

2014-03-31

ePix is a novel class of ASIC architectures, based on a common platform, optimized to build modular scalable detectors for LCLS. The platform architecture is composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog-to-digital converters per column. It also implements a dedicated control interface and all the required support electronics to perform configuration, calibration and readout of the matrix. Based on this platform a class of front-end ASICs and several camera modules, meeting different requirements, can be developed by designing specific pixel architectures. This approach reduces development time andmore » expands the possibility of integration of detector modules with different size, shape or functionality in the same camera. The ePix platform is currently under development together with the first two integrating pixel architectures: ePix100 dedicated to ultra low noise applications and ePix10k for high dynamic range applications.« less

Piezoelectric actuators for active optics

NASA Astrophysics Data System (ADS)

Le Letty, R.; Barillot, F.; Fabbro, H.; Guay, Ph.; Cadiergues, L.

2017-11-01

Piezoelectric actuators find their first applications in active space optics. The purpose of this paper is to describe the state of the art and some applications. Piezo actuators display attractive features for space applications, such as precise positioning, unlubricated, non magnetic and compact features, and low power consumption. However, piezo mechanisms cannot be considered separately from their driving and control electronic. Piezo actuators, such as Amplified Piezo Actuators or Parallel Pre-stressed Actuators, initially designed under CNES contracts, shall find their first space flight applications in optics on the PHARAO Laser bench: • fine pointing of the laser beams, • laser cavity tuning. Breadboard mechanisms based on piezo actuators have also been tested for refocusing purposes. Other applications includes the improvement of the CCD resolution through an oversampling technique, such as in the SOHO/LASCO instrument, fast optical shutter operation, optical filter in combination with a Fabry - Perot interferometer, such as in future LIDAR for earth observation. The first applications shall be described and an overview of the future potential applications shall be given.

3-D video techniques in endoscopic surgery.

PubMed

Becker, H; Melzer, A; Schurr, M O; Buess, G

1993-02-01

Three-dimensional visualisation of the operative field is an important requisite for precise and fast handling of open surgical operations. Up to now it has only been possible to display a two-dimensional image on the monitor during endoscopic procedures. The increasing complexity of minimal invasive interventions requires endoscopic suturing and ligatures of larger vessels which are difficult to perform without the impression of space. Three-dimensional vision therefore may decrease the operative risk, accelerate interventions and widen the operative spectrum. In April 1992 a 3-D video system developed at the Nuclear Research Center Karlsruhe, Germany (IAI Institute) was applied in various animal experimental procedures and clinically in laparoscopic cholecystectomy. The system works with a single monitor and active high-speed shutter glasses. Our first trials with this new 3-D imaging system clearly showed a facilitation of complex surgical manoeuvres like mobilisation of organs, preparation in the deep space and suture techniques. The 3-D-system introduced in this article will enter the market in 1993 (Opticon Co., Karlsruhe, Germany.

Rejection of fluorescence background in resonance and spontaneous Raman microspectroscopy.

PubMed

Smith, Zachary J; Knorr, Florian; Pagba, Cynthia V; Wachsmann-Hogiu, Sebastian

2011-05-18

Raman spectroscopy is often plagued by a strong fluorescent background, particularly for biological samples. If a sample is excited with a train of ultrafast pulses, a system that can temporally separate spectrally overlapping signals on a picosecond timescale can isolate promptly arriving Raman scattered light from late-arriving fluorescence light. Here we discuss the construction and operation of a complex nonlinear optical system that uses all-optical switching in the form of a low-power optical Kerr gate to isolate Raman and fluorescence signals. A single 808 nm laser with 2.4 W of average power and 80 MHz repetition rate is split, with approximately 200 mW of 808 nm light being converted to < 5 mW of 404 nm light sent to the sample to excite Raman scattering. The remaining unconverted 808 nm light is then sent to a nonlinear medium where it acts as the pump for the all-optical shutter. The shutter opens and closes in 800 fs with a peak efficiency of approximately 5%. Using this system we are able to successfully separate Raman and fluorescence signals at an 80 MHz repetition rate using pulse energies and average powers that remain biologically safe. Because the system has no spare capacity in terms of optical power, we detail several design and alignment considerations that aid in maximizing the throughput of the system. We also discuss our protocol for obtaining the spatial and temporal overlap of the signal and pump beams within the Kerr medium, as well as a detailed protocol for spectral acquisition. Finally, we report a few representative results of Raman spectra obtained in the presence of strong fluorescence using our time-gating system.

Fast valve

DOEpatents

Van Dyke, William J.

1992-01-01

A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

QuadCam - A Quadruple Polarimetric Camera for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Skuljan, J.

A specialised quadruple polarimetric camera for space situational awareness, QuadCam, has been built at the Defence Technology Agency (DTA), New Zealand, as part of collaboration with the Defence Science and Technology Laboratory (Dstl), United Kingdom. The design was based on a similar system originally developed at Dstl, with some significant modifications for improved performance. The system is made up of four identical CCD cameras looking in the same direction, but in a different plane of polarisation at 0, 45, 90 and 135 degrees with respect to the reference plane. A standard set of Stokes parameters can be derived from the four images in order to describe the state of polarisation of an object captured in the field of view. The modified design of the DTA QuadCam makes use of four small Raspberry Pi computers, so that each camera is controlled by its own computer in order to speed up the readout process and ensure that the four individual frames are taken simultaneously (to within 100-200 microseconds). In addition, a new firmware was requested from the camera manufacturer so that an output signal is generated to indicate the state of the camera shutter. A specialised GPS unit (also developed at DTA) is then used to monitor the shutter signals from the four cameras and record the actual time of exposure to an accuracy of about 100 microseconds. This makes the system well suited for the observation of fast-moving objects in the low Earth orbit (LEO). The QuadCam is currently mounted on a Paramount MEII robotic telescope mount at the newly built DTA space situational awareness observatory located on Whangaparaoa Peninsula near Auckland, New Zealand. The system will be used for tracking satellites in low Earth orbit and geostationary belt as well. The performance of the camera has been evaluated and a series of test images have been collected in order to derive the polarimetric signatures for selected satellites.

Uncooled detectors optimized for unattended applications

NASA Astrophysics Data System (ADS)

Malkinson, E.; Fraenkel, A.; Mizrahi, U.; Ben-Ezra, M.; Bikov, L.; Adin, A.; Zabar, Y.; Seter, D.; Kopolovich, Z.

2005-10-01

SCD has recently presented an uncooled detector product line based on the high-end VOx bolometer technology. The first FPA launched, named BIRD - short for Bolometer Infra Red Detector, is a 384x288 (or 320x240) configurable format with 25μm pitch. Typical NETD values for these FPAs range at 50mK with an F/1 aperture and 60 Hz frame rate. These detectors also exhibit a relatively fast thermal time constant of approximately 10 msec, as reported previously. In this paper, the special features of BIRD optimized for unattended sensor applications are presented and discussed. Unattended surveillance using sensors on unattended aerial vehicles (UAV's) or micro air vehicles (MAV's) , unattended ground vehicles (UGV's) or unattended ground sensor (UGS) are growing applications for uncooled detectors. This is due to their low power consumption, low weight, negligible acoustic noise and reduced price. On the other hand, uncooled detectors are vulnerable to ambient drift. Even minor temperature fluctuations are manifested as fixed pattern noise (FPN). As a result, frequent, shutter operation must be applied, with the risk of blocking the scenery in critical time frames and loosing information for various scenarios. In order to increase the time span between shutter operations, SCD has incorporated various features within the FPA and supporting algorithms. This paper will discuss these features and present some illustrative examples. Minimum power consumption is another critical issue for unattended applications. SCD has addressed this topic by introducing the "Power Save" concept. For very low power applications or for TEC-less (Thermo-Electric-Cooler) applications, the flexible dilution architecture enables the system to operate the detector at a number of formats. This, together with a smooth frame rate and format transition capability turns SCD's uncooled detector to be well suited for unattended applications. These issues will be described in detail as well.

Monte Carlo and analytical calculations for characterization of gas bremsstrahlung in ILSF insertion devices

NASA Astrophysics Data System (ADS)

Salimi, E.; Rahighi, J.; Sardari, D.; Mahdavi, S. R.; Lamehi Rachti, M.

2014-12-01

Gas bremsstrahlung is generated in high energy electron storage rings through interaction of the electron beam with the residual gas molecules in vacuum chamber. In this paper, Monte Carlo calculation has been performed to evaluate radiation hazard due to gas bremsstrahlung in the Iranian Light Source Facility (ILSF) insertion devices. Shutter/stopper dimensions is determined and dose rate from the photoneutrons via the giant resonance photonuclear reaction which takes place inside the shutter/stopper is also obtained. Some other characteristics of gas bremsstrahlung such as photon fluence, energy spectrum, angular distribution and equivalent dose in tissue equivalent phantom have also been investigated by FLUKA Monte Carlo code.

High dynamic range CMOS (HDRC) imagers for safety systems

NASA Astrophysics Data System (ADS)

Strobel, Markus; Döttling, Dietmar

2013-04-01

The first part of this paper describes the high dynamic range CMOS (HDRC®) imager - a special type of CMOS image sensor with logarithmic response. The powerful property of a high dynamic range (HDR) image acquisition is detailed by mathematical definition and measurement of the optoelectronic conversion function (OECF) of two different HDRC imagers. Specific sensor parameters will be discussed including the pixel design for the global shutter readout. The second part will give an outline on the applications and requirements of cameras for industrial safety. Equipped with HDRC global shutter sensors SafetyEYE® is a high-performance stereo camera system for safe three-dimensional zone monitoring enabling new and more flexible solutions compared to existing safety guards.

Characteristics of color optical shutter with dye-doped polymer network liquid crystal.

PubMed

Lee, G H; Hwang, K Y; Jang, J E; Jin, Y W; Lee, S Y; Jung, J E

2011-03-01

The optical properties and the theoretical prediction of color optical shutter with dye-doped polymer network liquid crystal (PNLC) were investigated. The view-angle dependence of reflectance according to the bias conditions showed distinctive characteristics, which could be explained from the effects of dye absorption and path length. It was also shown that the thickness dependence of reflectance was strongly influenced by the light-scattering coefficient. Our experimental results matched up well with the theoretical prediction based on the light scattering of liquid crystals in polymer network and the absorption of dichroic dye. This work indicates potential to improve the optical device using dye-doped liquid crystal-polymer composite.

Fault tolerant function of dynamic refreshing holographic memory with shutter-less optical feedback circuit

NASA Astrophysics Data System (ADS)

Okamoto, Atsushi; Ito, Terumasa; Bunsen, Masatoshi; Takayama, Yoshihisa

2005-11-01

The optical system, consisting of two photorefractive memories and a shutter-less optical feedback circuit, will be demonstrated to function as data mirroring. This function is known to automatically detect the data dropout and restore data, using unimpaired data in another memory, in the event that part or all of the data in either of them were lost for some reason. This memory system also can cope with a damaged hologram, a result of reading beams, which is a disadvantage of rewritable photorefractive memory, to ensure non-destructive holographic reading. It can be achieved by using no electronic circuits or mechanical structures; our optical experimental method in particular obtains this basic action.

Beam shuttering interferometer and method

DOEpatents

Deason, V.A.; Lassahn, G.D.

1993-07-27

A method and apparatus resulting in the simplification of phase shifting interferometry by eliminating the requirement to know the phase shift between interferograms or to keep the phase shift between interferograms constant. The present invention provides a simple, inexpensive means to shutter each independent beam of the interferometer in order to facilitate the data acquisition requirements for optical interferometry and phase shifting interferometry. By eliminating the requirement to know the phase shift between interferograms or to keep the phase shift constant, a simple, economical means and apparatus for performing the technique of phase shifting interferometry is provide which, by thermally expanding a fiber optical cable changes the optical path distance of one incident beam relative to another.

Beam shuttering interferometer and method

DOEpatents

Deason, Vance A.; Lassahn, Gordon D.

1993-01-01

A method and apparatus resulting in the simplification of phase shifting interferometry by eliminating the requirement to know the phase shift between interferograms or to keep the phase shift between interferograms constant. The present invention provides a simple, inexpensive means to shutter each independent beam of the interferometer in order to facilitate the data acquisition requirements for optical interferometry and phase shifting interferometry. By eliminating the requirement to know the phase shift between interferograms or to keep the phase shift constant, a simple, economical means and apparatus for performing the technique of phase shifting interferometry is provide which, by thermally expanding a fiber optical cable changes the optical path distance of one incident beam relative to another.

Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel †

PubMed Central

Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

2018-01-01

We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e−/s at 60 °C. PMID:29370146

Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel.

PubMed

Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

2018-01-25

Abstract : We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e - /s at 60 °C.

Inexpensive driver for stereo videogame glasses

NASA Astrophysics Data System (ADS)

Pique, Michael; Coogan, Anthony

1990-09-01

We have adapted home videogame glasses from Sega as workstation stereo viewers. A small (4x7x9 cm.) box of electronics receives sync signals in parallel with the monitor (either separate ROB-Sync or composite video) and drives the glasses.The view is dimmer than with costlier shutters, there is more ghosting, and the user is feuered by the wires. But the glasses are so much cheaper than the full-screen shutters (250 instead of about 10 000) that it is practical to provide the benefits of stereo to many more workstation users. We are using them with Sun TAAC-1 workstations; the interlaced video can also be recorded on ordinary NTSC videotape and played on television monitors.

Fast valve

DOEpatents

Van Dyke, W.J.

1992-04-07

A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

Robust fast controller design via nonlinear fractional differential equations.

PubMed

Zhou, Xi; Wei, Yiheng; Liang, Shu; Wang, Yong

2017-07-01

A new method for linear system controller design is proposed whereby the closed-loop system achieves both robustness and fast response. The robustness performance considered here means the damping ratio of closed-loop system can keep its desired value under system parameter perturbation, while the fast response, represented by rise time of system output, can be improved by tuning the controller parameter. We exploit techniques from both the nonlinear systems control and the fractional order systems control to derive a novel nonlinear fractional order controller. For theoretical analysis of the closed-loop system performance, two comparison theorems are developed for a class of fractional differential equations. Moreover, the rise time of the closed-loop system can be estimated, which facilitates our controller design to satisfy the fast response performance and maintain the robustness. Finally, numerical examples are given to illustrate the effectiveness of our methods. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

The BepiColombo SERENA/ELENA sensor. Approaching final delivery: sensor description and recent results

NASA Astrophysics Data System (ADS)

Orsini, S.; Selci, S.; Di Lellis, A. M.; Mura, A.; De Angelis, E.; Milillo, A.; Leoni, R.; Dandouras, I.; Scheer, J.; Wurz, P.

2012-04-01

The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV, within 1-D (4.5°x76°). ELENA is a Time-of-Flight (TOF) system, based on oscillating shutter (operated at frequencies up to 50 kHz) and mechanical gratings: the incoming neutral particles directly impinge upon the entrance with a definite timing (START) and arrive to a STOP detector after a flight path. In this way the low-energy neutral particles are directly detected, without using elements of interaction. The new results of the development of the BepiColombo SERENA/ELENA instrument are presented in the frame of the scientific items (instrument simulations, laboratory testing, etc.). In particular, the actual status of the ELENA TOF sections (shuttering system and MCPs) are reported in the light of recent testing results. The sensor performances are investigated, as well as their capability to accomplish the scientific requirements (new deflector system, shuttering functionality test, MCP efficiency, piezo driver and proximity boards, etc.).

Investigating MALDI MSI parameters (Part 2) - On the use of a mechanically shuttered trigger system for improved laser energy stability.

PubMed

Steven, Rory T; Dexter, Alex; Bunch, Josephine

2016-07-15

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is now widely used to desorb, ionize and detect molecules from complex samples and tissue sections. The detected ion intensity within MALDI MS and MSI is intimately linked to the laser energy per pulse incident upon the sample during analysis. Laser energy/power stability can be significantly affected by the manner in which the laser is operated. High-repetition rate diode-pumped solid-state (DPSS) lasers are being increasingly adopted to enable high-throughput MALDI MSI analysis. Within this work two different laser-triggering setups are used to demonstrate the effect of laser energy instabilities due to spiking and thermal control phenomena and a setup with a shutter to remove these effects. The effect of non-equilibrium laser operation on MALDI MSI data versus the more stable laser pulse energy of the shutter-triggered system is demonstrated in thin films of α-cyano-4-hydroxycinnamic acid (CHCA) and for imaging of murine brain tissue sections. Significant unwanted variations in absolute and relative detected ion intensity are shown where energy variation is introduced by these phenomena, which return to equilibrium within the setup employed here over timescales relevant to MALDI MS analysis. Copyright © 2016 Elsevier Inc. All rights reserved.

Microshutter Array Development for the Multi-Object Spectrograph for the New Generation Space Telescope, and Its Ground-based Demonstrator

NASA Technical Reports Server (NTRS)

Woodgate, Bruce E.; Moseley, Harvey; Fettig, Rainer; Kutyrev, Alexander; Ge, Jian; Fisher, Richard R. (Technical Monitor)

2001-01-01

The 6.5-m NASA/ESA/Canada New Generation Space Telescope to be operated at the L2 Lagrangian point will require a multi-object spectrograph (MOS) operating from 1 to 5 microns. Up to 3000 targets will be selected for simultaneous spectroscopy using a programmable cryogenic (approx. 35K) aperture array, consisting of a mosaic of arrays of micromirrors or microshutters. We describe the current status of the GSFC microshutter array development. The 100 micron square shutters are opened magnetically and latched open or closed electrostatically. Selection will be by two crossed one-dimensional addressing circuits. We will demonstrate the use of a 512 x 512 unit array on a ground-based IR MOS which will cover 0.6 to 5 microns, and operate rapidly to include spectroscopy of gamma ray burst afterglows.

Himalayan Mtns. and Mt. Everest Earth observation taken by Dan Bursch during EXP. Four

NASA Image and Video Library

2002-03-20

ISS004-E-8852 (20 March 2002) --- Astronaut Daniel W. Bursch, flight engineer for Expedition Four aboard the International Space Station, used a digital still camera to capture this image of Mt. Everest in the Himalayan Range. The mountain is near frame center. Here are the notes Bursch added in one of his reports to ground controllers: "One morning I happened to be up early. I glanced at our world map and saw that we’d be passing near Mt Everest soon. I checked the computer, realized that we were in an attitude that would allow me to open the window shutter and there was Mt Everest! It almost seemed to jump out at me. The low sun angle (it was close to orbital sunrise) gave tremendous relief to the mountains. It was just one of those sights that will be forever burned into my brain!"

Next-Generation Microshutter Arrays for Large-Format Imaging and Spectroscopy

NASA Technical Reports Server (NTRS)

Moseley, Samuel; Kutyrev, Alexander; Brown, Ari; Li, Mary

2012-01-01

A next-generation microshutter array, LArge Microshutter Array (LAMA), was developed as a multi-object field selector. LAMA consists of small-scaled microshutter arrays that can be combined to form large-scale microshutter array mosaics. Microshutter actuation is accomplished via electrostatic attraction between the shutter and a counter electrode, and 2D addressing can be accomplished by applying an electrostatic potential between a row of shutters and a column, orthogonal to the row, of counter electrodes. Microelectromechanical system (MEMS) technology is used to fabricate the microshutter arrays. The main feature of the microshutter device is to use a set of standard surface micromachining processes for device fabrication. Electrostatic actuation is used to eliminate the need for macromechanical magnet actuating components. A simplified electrostatic actuation with no macro components (e.g. moving magnets) required for actuation and latching of the shutters will make the microshutter arrays robust and less prone to mechanical failure. Smaller-size individual arrays will help to increase the yield and thus reduce the cost and improve robustness of the fabrication process. Reducing the size of the individual shutter array to about one square inch and building the large-scale mosaics by tiling these smaller-size arrays would further help to reduce the cost of the device due to the higher yield of smaller devices. The LAMA development is based on prior experience acquired while developing microshutter arrays for the James Webb Space Telescope (JWST), but it will have different features. The LAMA modular design permits large-format mosaicking to cover a field of view at least 50 times larger than JWST MSA. The LAMA electrostatic, instead of magnetic, actuation enables operation cycles at least 100 times faster and a mass significantly smaller compared to JWST MSA. Also, standard surface micromachining technology will simplify the fabrication process, increasing yield and reducing cost.

Conceptual phase A design of a cryogenic shutter mechanism for the SAFARI flight instrument

NASA Astrophysics Data System (ADS)

Eigenmann, Max; Wehmeier, Udo J.; Vuilleumier, Aurèle; Messina, Gabriele; Meyer, Michael R.

2012-09-01

We present a conceptual design for a cryogenic optical mechanism for the SAFARI instrument. SAFARI is a long wavelength (34-210 micron) Imaging Fourier Transform Spectrometer (FTS) to fly as an ESA instrument on the JAXA SPICA mission projected to launch in 2021. SPICA is a large 3m class space telescope which will have an operating temperature of less than 7K. The SAFARI shutter is a single point of failure flight mechanism designed to operate in space at a temperature of 4K which meets redundancy and reliability requirements of this challenging mission. The conceptual design is part of a phase A study led by ETH Institute for Astronomy and conducted by RUAG Space AG.

Implementation and performance of shutterless uncooled micro-bolometer cameras

NASA Astrophysics Data System (ADS)

Das, J.; de Gaspari, D.; Cornet, P.; Deroo, P.; Vermeiren, J.; Merken, P.

2015-06-01

A shutterless algorithm is implemented into the Xenics LWIR thermal cameras and modules. Based on a calibration set and a global temperature coefficient the optimal non-uniformity correction is calculated onboard of the camera. The limited resources in the camera require a compact algorithm, hence the efficiency of the coding is important. The performance of the shutterless algorithm is studied by a comparison of the residual non-uniformity (RNU) and signal-to-noise ratio (SNR) between the shutterless and shuttered correction algorithm. From this comparison we conclude that the shutterless correction is only slightly less performant compared to the standard shuttered algorithm, making this algorithm very interesting for thermal infrared applications where small weight and size, and continuous operation are important.

How to align a new detector and micro shutter inside JWST's Near Infrared Spectrograph (NIRSpec)

NASA Astrophysics Data System (ADS)

te Plate, Maurice; Rumler, Peter; Jensen, Peter; Eder, Robert; Ehrenwinkler, Ralf; Merkle, Frank; Roedel, Andreas; Speckmaier, Max; Johnson, Thomas E.; Mott, Brent; Snodgrass, Stephen; Gunn, Chris; Ward, Justin

2016-09-01

JWST will be the biggest space telescope ever built and it will lead to astounding scientific breakthroughs. The mission will be launched in October 2018 from Kourou, French Guyana by an ESA provided Ariane 5 rocket. NIRSpec, one of the four instruments on board of the mission, recently underwent a major upgrade. New infrared detectors were installed and the Micro Shutter Assembly (MSA) was replaced as well. The rework was necessary because both systems were found to be degrading beyond a level that could be accepted. The installation and "in situ" alignment of these new systems required special techniques and alignment jigs that will be described in this paper. Some first results will be presented as well.

Quantum-shutter approach to tunneling time scales with wave packets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, Norifumi; Garcia-Calderon, Gaston; Villavicencio, Jorge

2005-07-15

The quantum-shutter approach to tunneling time scales [G. Garcia-Calderon and A. Rubio, Phys. Rev. A 55, 3361 (1997)], which uses a cutoff plane wave as the initial condition, is extended to consider certain type of wave packet initial conditions. An analytical expression for the time-evolved wave function is derived. The time-domain resonance, the peaked structure of the probability density (as the function of time) at the exit of the barrier, originally found with the cutoff plane wave initial condition, is studied with the wave packet initial conditions. It is found that the time-domain resonance is not very sensitive to themore » width of the packet when the transmission process occurs in the tunneling regime.« less

The NACA High-Speed Motion-Picture Camera Optical Compensation at 40,000 Photographs Per Second

NASA Technical Reports Server (NTRS)

Miller, Cearcy D

1946-01-01

The principle of operation of the NACA high-speed camera is completely explained. This camera, operating at the rate of 40,000 photographs per second, took the photographs presented in numerous NACA reports concerning combustion, preignition, and knock in the spark-ignition engine. Many design details are presented and discussed, details of an entirely conventional nature are omitted. The inherent aberrations of the camera are discussed and partly evaluated. The focal-plane-shutter effect of the camera is explained. Photographs of the camera are presented. Some high-speed motion pictures of familiar objects -- photoflash bulb, firecrackers, camera shutter -- are reproduced as an illustration of the quality of the photographs taken by the camera.

The scheme for evaluation of isotopic composition of fast reactor core in closed nuclear fuel cycle

NASA Astrophysics Data System (ADS)

Saldikov, I. S.; Ternovykh, M. Yu; Fomichenko, P. A.; Gerasimov, A. S.

2017-01-01

The PRORYV (i.e. «Breakthrough» in Russian) project is currently under development. Within the framework of this project, fast reactors BN-1200 and BREST-OD-300 should be built to, inter alia, demonstrate possibility of the closed nuclear fuel cycle technologies with plutonium as a main source of power. Russia has a large inventory of plutonium which was accumulated in the result of reprocessing of spent fuel of thermal power reactors and conversion of nuclear weapons. This kind of plutonium will be used for development of initial fuel assemblies for fast reactors. To solve the closed nuclear fuel modeling tasks REPRORYV code was developed. It simulates the mass flow for nuclides in the closed fuel cycle. This paper presents the results of modeling of a closed nuclear fuel cycle, nuclide flows considering the influence of the uncertainty on the outcome of neutron-physical characteristics of the reactor.

Methods of dark signal determination for CCD array spectroradiometers used in solar UVR measurements.

PubMed

Baczynska, K A; Khazova, M

2015-02-01

The methods of the dark signal determination by direct contemporaneous measurements using a light spectrum and modelling of the dark signal based on the dark signal characterisation data were discussed. These techniques were tested with two charge-couple detectors (CCD) array spectroradiometers used in solar UVR measurements. The sensitivity of both instruments was significantly reduced when shutters were used; the measured signal varied by up to 12% depending on the orientation of the shutter. The shutters should be permanently attached to the SSR, so that the orientation cannot be changed to prevent an increase in uncertainty. The method of using blind pixels from the optically inactive part of the CCD array in a light spectrum could be used to derive the dark signal with some limitations for integration times <10 s for the QE65000. An alternative method of deriving the dark signal from light measurements using out-of-range pixels has been proved impossible due to out-of-range stray light in both instruments. The dark signal was characterised for the range of integration times and ambient temperatures of 15-35°C. Based on these data, the model of the dark signal was developed so that a single value of the dark signal can be subtracted over the whole spectral range if the instrument temperature is known. © Crown copyright 2014.

Laser line scan underwater imaging by complementary metal-oxide-semiconductor camera

NASA Astrophysics Data System (ADS)

He, Zhiyi; Luo, Meixing; Song, Xiyu; Wang, Dundong; He, Ning

2017-12-01

This work employs the complementary metal-oxide-semiconductor (CMOS) camera to acquire images in a scanning manner for laser line scan (LLS) underwater imaging to alleviate backscatter impact of seawater. Two operating features of the CMOS camera, namely the region of interest (ROI) and rolling shutter, can be utilized to perform image scan without the difficulty of translating the receiver above the target as the traditional LLS imaging systems have. By the dynamically reconfigurable ROI of an industrial CMOS camera, we evenly divided the image into five subareas along the pixel rows and then scanned them by changing the ROI region automatically under the synchronous illumination by the fun beams of the lasers. Another scanning method was explored by the rolling shutter operation of the CMOS camera. The fun beam lasers were turned on/off to illuminate the narrow zones on the target in a good correspondence to the exposure lines during the rolling procedure of the camera's electronic shutter. The frame synchronization between the image scan and the laser beam sweep may be achieved by either the strobe lighting output pulse or the external triggering pulse of the industrial camera. Comparison between the scanning and nonscanning images shows that contrast of the underwater image can be improved by our LLS imaging techniques, with higher stability and feasibility than the mechanically controlled scanning method.

Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

PubMed

Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P

1994-10-01

Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.

Precise starshade stationkeeping and pointing with a Zernike wavefront sensor

NASA Astrophysics Data System (ADS)

Bottom, Michael; Martin, Stefan; Seubert, Carl; Cady, Eric; Zareh, Shannon Kian; Shaklan, Stuart

2017-09-01

Starshades, large occulters positioned tens of thousands of kilometers in front of space telescopes, offer one of the few paths to imaging and characterizing Earth-like extrasolar planets. However, for a starshade to generate a sufficiently dark shadow on the telescope, the two must be coaligned to just 1 meter laterally, even at these large separations. The principal challenge to achieving this level of control is in determining the position of the starshade with respect to the space telescope. In this paper, we present numerical simulations and laboratory results demonstrating that a Zernike wavefront sensor coupled to a WFIRST-type telescope is able to deliver the stationkeeping precision required, by measuring light outside of the science wavelengths. The sensor can determine the starshade lateral position to centimeter level in seconds of open shutter time for stars brighter than eighth magnitude, with a capture range of 10 meters. We discuss the potential for fast (ms) tip/tilt pointing control at the milli-arcsecond level by illuminating the sensor with a laser mounted on the starshade. Finally, we present early laboratory results.

03pd0676

NASA Image and Video Library

2003-03-07

File name :DSC_0749.JPG File size :1.1MB(1174690Bytes) Date taken :2003/03/07 13:51:29 Image size :2000 x 1312 Resolution :300 x 300 dpi Number of bits :8bit/channel Protection attribute :Off Hide Attribute :Off Camera ID :N/A Camera :NIKON D1H Quality mode :FINE Metering mode :Matrix Exposure mode :Shutter priority Speed light :No Focal length :20 mm Shutter speed :1/500second Aperture :F11.0 Exposure compensation :0 EV White Balance :Auto Lens :20 mm F 2.8 Flash sync mode :N/A Exposure difference :0.0 EV Flexible program :No Sensitivity :ISO200 Sharpening :Normal Image Type :Color Color Mode :Mode II(Adobe RGB) Hue adjustment :3 Saturation Control :N/A Tone compensation :Normal Latitude(GPS) :N/A Longitude(GPS) :N/A Altitude(GPS) :N/A

A math model for high velocity sensoring with a focal plane shuttered camera.

NASA Technical Reports Server (NTRS)

Morgan, P.

1971-01-01

A new mathematical model is presented which describes the image produced by a focal plane shutter-equipped camera. The model is based upon the well-known collinearity condition equations and incorporates both the translational and rotational motion of the camera during the exposure interval. The first differentials of the model with respect to exposure interval, delta t, yield the general matrix expressions for image velocities which may be simplified to known cases. The exposure interval, delta t, may be replaced under certain circumstances with a function incorporating blind velocity and image position if desired. The model is tested using simulated Lunar Orbiter data and found to be computationally stable as well as providing excellent results, provided that some external information is available on the velocity parameters.

03pd0517

NASA Image and Video Library

2002-02-19

File name :DSC_0028.JPG File size :2.8MB(2950833Bytes) Date taken :2002/02/19 09:49:01 Image size :3008 x 2000 Resolution :300 x 300 dpi Number of bits :8bit/channel Protection attribute :Off Hide Attribute :Off Camera ID :N/A Camera :NIKON D100 Quality mode :N/A Metering mode :Matrix Exposure mode :Shutter priority Speed light :Yes Focal length :24 mm Shutter speed :1/60second Aperture :F3.5 Exposure compensation :0 EV White Balance :N/A Lens :N/A Flash sync mode :N/A Exposure difference :N/A Flexible program :N/A Sensitivity :N/A Sharpening :N/A Image Type :Color Color Mode :N/A Hue adjustment :N/A Saturation Control :N/A Tone compensation :N/A Latitude(GPS) :N/A Longitude(GPS) :N/A Altitude(GPS) :N/A

03pd0535

NASA Image and Video Library

2002-02-24

File name :DSC_0047.JPG File size :2.8MB(2931574Bytes) Date taken :2002/02/24 10:06:57 Image size :3008 x 2000 Resolution :300 x 300 dpi Number of bits :8bit/channel Protection attribute :Off Hide Attribute :Off Camera ID :N/A Camera :NIKON D100 Quality mode :N/A Metering mode :Matrix Exposure mode :Shutter priority Speed light :Yes Focal length :24 mm Shutter speed :1/180second Aperture :F20.0 Exposure compensation :+0.3 EV White Balance :N/A Lens :N/A Flash sync mode :N/A Exposure difference :N/A Flexible program :N/A Sensitivity :N/A Sharpening :N/A Image Type :Color Color Mode :N/A Hue adjustment :N/A Saturation Control :N/A Tone compensation :N/A Latitude(GPS) :N/A Longitude(GPS) :N/A Altitude(GPS) :N/A

Low-power priority Address-Encoder and Reset-Decoder data-driven readout for Monolithic Active Pixel Sensors for tracker system

NASA Astrophysics Data System (ADS)

Yang, P.; Aglieri, G.; Cavicchioli, C.; Chalmet, P. L.; Chanlek, N.; Collu, A.; Gao, C.; Hillemanns, H.; Junique, A.; Kofarago, M.; Keil, M.; Kugathasan, T.; Kim, D.; Kim, J.; Lattuca, A.; Marin Tobon, C. A.; Marras, D.; Mager, M.; Martinengo, P.; Mazza, G.; Mugnier, H.; Musa, L.; Puggioni, C.; Rousset, J.; Reidt, F.; Riedler, P.; Snoeys, W.; Siddhanta, S.; Usai, G.; van Hoorne, J. W.; Yi, J.

2015-06-01

Active Pixel Sensors used in High Energy Particle Physics require low power consumption to reduce the detector material budget, low integration time to reduce the possibilities of pile-up and fast readout to improve the detector data capability. To satisfy these requirements, a novel Address-Encoder and Reset-Decoder (AERD) asynchronous circuit for a fast readout of a pixel matrix has been developed. The AERD data-driven readout architecture operates the address encoding and reset decoding based on an arbitration tree, and allows us to readout only the hit pixels. Compared to the traditional readout structure of the rolling shutter scheme in Monolithic Active Pixel Sensors (MAPS), AERD can achieve a low readout time and a low power consumption especially for low hit occupancies. The readout is controlled at the chip periphery with a signal synchronous with the clock, allows a good digital and analogue signal separation in the matrix and a reduction of the power consumption. The AERD circuit has been implemented in the TowerJazz 180 nm CMOS Imaging Sensor (CIS) process with full complementary CMOS logic in the pixel. It works at 10 MHz with a matrix height of 15 mm. The energy consumed to read out one pixel is around 72 pJ. A scheme to boost the readout speed to 40 MHz is also discussed. The sensor chip equipped with AERD has been produced and characterised. Test results including electrical beam measurement are presented.

Fixing the Leak: Empirical Corrections for the Small Light Leak in Hinode XRT

NASA Astrophysics Data System (ADS)

Saar, Steven H.; DeLuca, E. E.; McCauley, P.; Kobelski, A.

2013-07-01

On May 9, 2012, the the straylight level of XRT on Hinode suddenly increased, consistent with the appearance of a pinhole in the entrance filter (possibly a micrometeorite breach). The effect of this event is most noticeable in the optical G band data, which shows an average light excess of ~30%. However, data in several of the X-ray filters is also affected, due to low sensitivity "tails" of their filter responses into the visible. Observations taken with the G band filter but with the visible light shutter (VLS) closed show a weak, slightly shifted, out-of-focus image, revealing the leaked light. The intensity of the leak depends on telescope pointing, dropping strongly for images taken off-disk. By monitoring light levels in the corners of full-Sun Ti-poly filter images, we determine the approximate time of the event: ~13:30 UT. We use pairs of images taken just-before and after the filter breach to directly measure the leakage in two affected X-ray filters. We then develop a model using a scaled, shifted, and smoothed versions of the VLS closed images to remove the contamination. We estimate the uncertainties involved in our proposed correction procedure. This research was supported under NASA contract NNM07AB07C for Hinode XRT.

40 CFR 92.204 - Designation of engine families.

Code of Federal Regulations, 2010 CFR

2010-07-01

... stroke dimensions; (4) The approximate intake and exhaust event timing and duration (valve or port); (5... shutters, etc.); (3) The approximate bore and stroke dimensions; (4) The approximate location of the intake...

40 CFR 92.204 - Designation of engine families.

Code of Federal Regulations, 2013 CFR

2013-07-01

... stroke dimensions; (4) The approximate intake and exhaust event timing and duration (valve or port); (5... shutters, etc.); (3) The approximate bore and stroke dimensions; (4) The approximate location of the intake...

40 CFR 92.204 - Designation of engine families.

Code of Federal Regulations, 2012 CFR

2012-07-01

... stroke dimensions; (4) The approximate intake and exhaust event timing and duration (valve or port); (5... shutters, etc.); (3) The approximate bore and stroke dimensions; (4) The approximate location of the intake...

40 CFR 92.204 - Designation of engine families.

Code of Federal Regulations, 2014 CFR

2014-07-01

... stroke dimensions; (4) The approximate intake and exhaust event timing and duration (valve or port); (5... shutters, etc.); (3) The approximate bore and stroke dimensions; (4) The approximate location of the intake...

40 CFR 92.204 - Designation of engine families.

Code of Federal Regulations, 2011 CFR

2011-07-01

... stroke dimensions; (4) The approximate intake and exhaust event timing and duration (valve or port); (5... shutters, etc.); (3) The approximate bore and stroke dimensions; (4) The approximate location of the intake...

Adaptive-randomised self-calibration of electro-mechanical shutters for space imaging

NASA Astrophysics Data System (ADS)

De Cecco, Mariolino; Debei, Stefano; Zaccariotto, Mirco; Pertile, Marco

2006-11-01

This work describes the self-calibration of a high-precision open-loop mechanism. The self-calibration method is applied to a mechanical shutter for space applications, which was launched onboard the ESA-ROSETTA mission (launch: 2 March 2004). It is based on an adaptive 'model reference' and a 'randomised' search method which may be generalised to applications in which high performance and functionality are strongly interconnected. The method makes use of an adaptive 'model-reference' control approach [K.J. Astrom, B. Wittenmark, On self-tuning regulators Automatica 9 (1973) 185-199 [16]; K.J. Astrom, Theory and application of adaptive control, in: Proceedings of the Eighth IFAC World Conference, Kyoto, Japan, 1981 [17]; D.E. Seborg, S.L. Shah, T.F. Edgar, Adaptive control strategies for process control, AIChE Journal 6(32) (1986) 881-895 [18

Defining the safe current limit for opening ID photon shutter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seletskiy, S.

The NSLS-II storage ring is protected from possible damage from insertion devices (IDs) synchrotron radiation by a dedicated active interlock system (AIS). It monitors electron beam position and angle and triggers beam drop if beam orbit exceeds the boundaries of pre-calculated active interlock envelope (AIE). The beamlines (BL) and beamline frontends (FE) are designed under assumption that the electron beam is interlocked within the AIE. For historic reasons the AIS engages the ID active interlock (AI-ID) at any non-zero beam current whenever the ID photon shutter (IDPS) is getting opened. Such arrangement creates major inconveniences for BLs commissioning. Apparently theremore » is some IDPS safe current limit (SCL) under which the IDPS can be opened without interlocking the e-beam. The goal of this paper is to find such limit.« less

All-fiber 80-Gbit/s wavelength converter using 1-m-long Bismuth Oxide-based nonlinear optical fiber with a nonlinearity gamma of 1100 W-1km-1.

PubMed

Lee, Ju Han; Kikuchi, Kazuro; Nagashima, Tatsuo; Hasegawa, Tomoharu; Ohara, Seiki; Sugimoto, Naoki

2005-04-18

We experimentally demonstrate the use of our fabricated 1-m-long Bi2O3 optical fiber (Bi-NLF) with an ultra-high nonlinearity of ~1100 W-1km-1 for wavelength conversion of OTDM signals. With successfully performed fusion splicing of the Bi-NLF to conventional silica fibers an all-fiber wavelength converter is readily implemented by use of a conventional Kerr shutter configuration. Owing to the extremely short fiber length, no additional scheme was employed for suppression of signal polarization fluctuation induced by local birefringence fluctuation, which is usually observed in a long-fiber Kerr shutter. The wavelength converter, composed of the 1-m Bi-NLF readily achieves error-free wavelength conversion of an 80-Gbit/s input signal.

Specialised use of working memory by Portia africana, a spider-eating salticid.

PubMed

Cross, Fiona R; Jackson, Robert R

2014-03-01

Using expectancy-violation methods, we investigated the role of working memory in the predatory strategy of Portia africana, a salticid spider from Kenya that preys by preference on other spiders. One of this predator's tactics is to launch opportunistic leaping attacks on to other spiders in their webs. Focussing on this particular tactic, our experiments began with a test spider on a ramp facing a lure (dead prey spider mounted on a cork disc) that could be reached by leaping. After the test spider faced the lure for 30 s, we blocked the test spider's view of the lure by lowering an opaque shutter before the spider leapt. When the shutter was raised 90 s later, either the same lure came into view again (control) or a different lure came into view (experimental: different prey type in same orientation or same prey type in different orientation). We recorded attack frequency (number of test spiders that leapt at the lure) and attack latency (time elapsing between shutter being raised and spiders initiating a leap). Attack latencies in control trials were not significantly different from attack latencies in experimental trials, regardless of whether it was prey type or prey orientation that changed in the experimental trials. However, compared with test spiders in the no-change control trials, significantly fewer test spiders leapt when prey type changed. There was no significant effect on attack frequency when prey orientation changed. These findings suggest that this predator represents prey type independently of prey orientation.

Tri-linear color multi-linescan sensor with 200 kHz line rate

NASA Astrophysics Data System (ADS)

Schrey, Olaf; Brockherde, Werner; Nitta, Christian; Bechen, Benjamin; Bodenstorfer, Ernst; Brodersen, Jörg; Mayer, Konrad J.

2016-11-01

In this paper we present a newly developed linear CMOS high-speed line-scanning sensor realized in a 0.35 μm CMOS OPTO process for line-scan with 200 kHz true RGB and 600 kHz monochrome line rate, respectively. In total, 60 lines are integrated in the sensor allowing for electronic position adjustment. The lines are read out in rolling shutter manner. The high readout speed is achieved by a column-wise organization of the readout chain. At full speed, the sensor provides RGB color images with a spatial resolution down to 50 μm. This feature enables a variety of applications like quality assurance in print inspection, real-time surveillance of railroad tracks, in-line monitoring in flat panel fabrication lines and many more. The sensor has a fill-factor close to 100%, preventing aliasing and color artefacts. Hence the tri-linear technology is robust against aliasing ensuring better inspection quality and thus less waste in production lines.

Comparative analysis of ROS-based monocular SLAM methods for indoor navigation

NASA Astrophysics Data System (ADS)

Buyval, Alexander; Afanasyev, Ilya; Magid, Evgeni

2017-03-01

This paper presents a comparison of four most recent ROS-based monocular SLAM-related methods: ORB-SLAM, REMODE, LSD-SLAM, and DPPTAM, and analyzes their feasibility for a mobile robot application in indoor environment. We tested these methods using video data that was recorded from a conventional wide-angle full HD webcam with a rolling shutter. The camera was mounted on a human-operated prototype of an unmanned ground vehicle, which followed a closed-loop trajectory. Both feature-based methods (ORB-SLAM, REMODE) and direct SLAMrelated algorithms (LSD-SLAM, DPPTAM) demonstrated reasonably good results in detection of volumetric objects, corners, obstacles and other local features. However, we met difficulties with recovering typical for offices homogeneously colored walls, since all of these methods created empty spaces in a reconstructed sparse 3D scene. This may cause collisions of an autonomously guided robot with unfeatured walls and thus limits applicability of maps, which are obtained by the considered monocular SLAM-related methods for indoor robot navigation.

New horizons for lipoprotein receptors: communication by β-propellers

PubMed Central

Andersen, Olav M.; Dagil, Robert; Kragelund, Birthe B.

2013-01-01

The lipoprotein receptor (LR) family constitutes a large group of structurally closely related receptors with broad ligand-binding specificity. Traditionally, ligand binding to LRs has been anticipated to involve merely the complement type repeat (CR)-domains omnipresent in the family. Recently, this dogma has transformed with the observation that β-propellers of some LRs actively engage in complex formation too. Based on an in-depth decomposition of current structures and sequences, we suggest that exploitation of the β-propellers as binding targets depends on receptor subgroups. In particular, we highlight the shutter mechanism of β-propellers as a general recognition motif for NxI-containing ligands, and we present indications that the generalized β-propeller-induced ligand release mechanism is not applicable for the larger LRs. For the giant LR members, we present evidence that their β-propellers may also actively engage in ligand binding. We therefore advocate for an increased focus on solving the structure-function relationship of this group of important biological receptors. PMID:23881912

An Autonomous System for Experimental Evolution of Microbial Cultures: Test Results Using Ultraviolet-C Radiation and Escherichia Coli.

NASA Technical Reports Server (NTRS)

Ouandji, Cynthia; Wang, Jonathan; Arismendi, Dillon; Lee, Alonzo; Blaich, Justin; Gentry, Diana

2017-01-01

At its core, the field of microbial experimental evolution seeks to elucidate the natural laws governing the history of microbial life by understanding its underlying driving mechanisms. However, observing evolution in nature is complex, as environmental conditions are difficult to control. Laboratory-based experiments for observing population evolution provide more control, but manually culturing and studying multiple generations of microorganisms can be time consuming, labor intensive, and prone to inconsistency. We have constructed a prototype, closed system device that automates the process of directed evolution experiments in microorganisms. It is compatible with any liquid microbial culture, including polycultures and field samples, provides flow control and adjustable agitation, continuously monitors optical density (OD), and can dynamically control environmental pressures such as ultraviolet-C (UV-C) radiation and temperature. Here, the results of the prototype are compared to iterative exposure and survival assays conducted using a traditional hood, UV-C lamp, and shutter system.

Optimal camera exposure for video surveillance systems by predictive control of shutter speed, aperture, and gain

NASA Astrophysics Data System (ADS)

Torres, Juan; Menéndez, José Manuel

2015-02-01

This paper establishes a real-time auto-exposure method to guarantee that surveillance cameras in uncontrolled light conditions take advantage of their whole dynamic range while provide neither under nor overexposed images. State-of-the-art auto-exposure methods base their control on the brightness of the image measured in a limited region where the foreground objects are mostly located. Unlike these methods, the proposed algorithm establishes a set of indicators based on the image histogram that defines its shape and position. Furthermore, the location of the objects to be inspected is likely unknown in surveillance applications. Thus, the whole image is monitored in this approach. To control the camera settings, we defined a parameters function (Ef ) that linearly depends on the shutter speed and the electronic gain; and is inversely proportional to the square of the lens aperture diameter. When the current acquired image is not overexposed, our algorithm computes the value of Ef that would move the histogram to the maximum value that does not overexpose the capture. When the current acquired image is overexposed, it computes the value of Ef that would move the histogram to a value that does not underexpose the capture and remains close to the overexposed region. If the image is under and overexposed, the whole dynamic range of the camera is therefore used, and a default value of the Ef that does not overexpose the capture is selected. This decision follows the idea that to get underexposed images is better than to get overexposed ones, because the noise produced in the lower regions of the histogram can be removed in a post-processing step while the saturated pixels of the higher regions cannot be recovered. The proposed algorithm was tested in a video surveillance camera placed at an outdoor parking lot surrounded by buildings and trees which produce moving shadows in the ground. During the daytime of seven days, the algorithm was running alternatively together with a representative auto-exposure algorithm in the recent literature. Besides the sunrises and the nightfalls, multiple weather conditions occurred which produced light changes in the scene: sunny hours that produced sharpen shadows and highlights; cloud coverages that softened the shadows; and cloudy and rainy hours that dimmed the scene. Several indicators were used to measure the performance of the algorithms. They provided the objective quality as regards: the time that the algorithms recover from an under or over exposure, the brightness stability, and the change related to the optimal exposure. The results demonstrated that our algorithm reacts faster to all the light changes than the selected state-of-the-art algorithm. It is also capable of acquiring well exposed images and maintaining the brightness stable during more time. Summing up the results, we concluded that the proposed algorithm provides a fast and stable auto-exposure method that maintains an optimal exposure for video surveillance applications. Future work will involve the evaluation of this algorithm in robotics.

6. Historic American Buildings Survey Josiah T. Tubby, Photographer September ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Historic American Buildings Survey Josiah T. Tubby, Photographer September 1936 SLIDING SHUTTERS (S. W. wall sitting room) - Jefferds Tavern, Harraseekit Road (moved to U.S. Route 1A, York), Wells, York County, ME

5. Historic American Buildings Survey E. W. Russell, Photographer, June ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Historic American Buildings Survey E. W. Russell, Photographer, June 17, 1937 CLOSEUP OF THE LOWER SECTION OF FIRST STORY WINDOW ON FRONT, SHOWING SHUTTER AND HINGE. - Wewoka, Riser Mill Road, Sylacauga, Talladega County, AL

33. Photocopy of drawing STANDARD PLAN L4, SHEET 6 OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. Photocopy of drawing STANDARD PLAN L-4, SHEET 6 OF 8; CROSS SECTION, FRONT ELEVATION WITH SHUTTERS, FIRE FINDER - Suntop Lookout, Forest Road 510, Mt. Baker-Snoqualmie National Forest, Greenwater, Pierce County, WA

The Rocket Electric Field Sounding (REFS) program: Prototype design and successful first launch

NASA Astrophysics Data System (ADS)

Willett, J. C.; Curtis, D. C.; Driesman, A. R.; Longstreth, R. K.; Rison, W.; Winn, W. P.; Jones, J. J.

1992-01-01

The motivation, design, and successful first flight of a sounding rocket to measure profiles of vector electrostatic field in the lower troposphere are described. The design employs eight shutter field mills amd a corona-charging system in a manner similar to aircraft previously instrumented for the measurement of electric fields. A rocket offers significant advantages over an aircraft in simplicity and calibration. A single cylindrical rotor covering most of the payload acts as the shutter for all eight mills in this design. The cylindrical symmetry and circular cross sections of the vehicle facilitate straightforward calibration. Also included in the payload are a pressure sensor, a longitudinal accelerometer, a transverse magnometer, and a novel cloud-penetration detector. A fair-weather test flight at the NASA Wallops Flight Facility demonstrated the workability of the basic design and identified a few necessary modifications.

Design, Qualification and Lessons Learned of the Shutter Calibration Mechanism for EnMAP Mission

NASA Astrophysics Data System (ADS)

Schmidt, Tilo; Muller, Silvio; Bergander, Arvid; Zajac, Kai; Seifart, Klaus

2015-09-01

The Shutter Calibration Mechanism (SCM) Assembly is one of three mechanisms which are developed by HTS for the EnMAP instrument in subcontract to OHB System AG Munich. EnMAP is the Environmental Mapping and Analysis Program of the German Space Agency DLR.The binary rotary encoder of the SCM using hall-effect sensors was already presented during ESMATS 2011. This paper summarizes the main functions and design features of the Hardware and focuses on qualification testing which has finished successfully in 2014. Of particular interest is the functional testing of the main drive including the precise hall-effect position sensing system and the test of the fail safe mechanism. In addition to standard test campaign required for QM also a shock emission measurement of the fail safe mechanism activation was conducted.Test conduction and results will be presented with focus on deviations from the expected behaviour, mitigation measures and on lessons learned.

An analysis of new techniqes for radiometric correction of LANDSAT-4 Thematic Mapper images. [Terrebonne Bay, Louisiana and Grand Bahamas scenes

NASA Technical Reports Server (NTRS)

Kogut, J.; Larduinat, E.; Fitzgerald, M.

1983-01-01

The utility of methods for generating TM RLUTS which can improve the quality of the resultant images was investigated. The TM-CCT-ADDS tape was changed to account for a different collection window for the calibration data. Several scenes of Terrebonne Bay, Louisiana and the Grand Bahamas were analyzed to evaluate the radiometric corrections operationally applied to the image data and to investigate several techniques for reducing striping in the images. Printer plots for the TM shutter data were produced and detector statistics were compiled and plotted. These statistics included various combinations of the average shutter counts for each scan before and after DC restore for forward and reverse scans. Results show that striping is caused by the detectors becoming saturated when they view a bright cloud and depress the DC restore level.

Electrically optofluidic zoom system with a large zoom range and high-resolution image.

PubMed

Li, Lei; Yuan, Rong-Ying; Wang, Jin-Hui; Wang, Qiong-Hua

2017-09-18

We report an electrically controlled optofluidic zoom system which can achieve a large continuous zoom change and high-resolution image. The zoom system consists of an optofluidic zoom objective and a switchable light path which are controlled by two liquid optical shutters. The proposed zoom system can achieve a large tunable focal length range from 36mm to 92mm. And in this tuning range, the zoom system can correct aberrations dynamically, thus the image resolution is high. Due to large zoom range, the proposed imaging system incorporates both camera configuration and telescope configuration into one system. In addition, the whole system is electrically controlled by three electrowetting liquid lenses and two liquid optical shutters, therefore, the proposed system is very compact and free of mechanical moving parts. The proposed zoom system has potential to take place of conventional zoom systems.

Rapid Optical Shutter, Chopper, Modulator and Deflector

NASA Technical Reports Server (NTRS)

Danehy, Paul M. (Inventor)

2017-01-01

An optical device with a light source and a detector is provided. A digital micromirror device positioned between the detector and the light source may deflect light beams projected from the light source. An aperture in front of the detector may block an incoming light beam from the detector when the incoming light beam is incident on the detector outside of a passable incident range and including an aperture opening configured to pass the incoming light beam to the detector when the incoming light beam is incident on the detector within a passable incident range. The digital micromirror device may rotate between a first position causing the light beam to pass through the aperture opening and a second position causing the light beam to be blocked by the aperture. The optical device may be configured to operate as a shutter, chopper, modulator and/or deflector.

A mixed reality approach for stereo-tomographic quantification of lung nodules.

PubMed

Chen, Mianyi; Kalra, Mannudeep K; Yun, Wenbing; Cong, Wenxiang; Yang, Qingsong; Nguyen, Terry; Wei, Biao; Wang, Ge

2016-05-25

To reduce the radiation dose and the equipment cost associated with lung CT screening, in this paper we propose a mixed reality based nodule measurement method with an active shutter stereo imaging system. Without involving hundreds of projection views and subsequent image reconstruction, we generated two projections of an iteratively placed ellipsoidal volume in the field of view and merging these synthetic projections with two original CT projections. We then demonstrated the feasibility of measuring the position and size of a nodule by observing whether projections of an ellipsoidal volume and the nodule are overlapped from a human observer's visual perception through the active shutter 3D vision glasses. The average errors of measured nodule parameters are less than 1 mm in the simulated experiment with 8 viewers. Hence, it could measure real nodules accurately in the experiments with physically measured projections.

Cavitation-based hydro-fracturing technique for geothermal reservoir stimulation

DOEpatents

Wang, Jy-An John; Wang, Hong; Ren, Fei; Cox, Thomas S.

2017-02-21

A rotary shutter valve 500 is used for geothermal reservoir stimulation. The valve 500 includes a pressure chamber 520 for holding a working fluid (F) under pressure. A rotatable shutter 532 is turned with a powering device 544 to periodically align one or more windows 534 with one or more apertures 526 in a bulkhead 524. When aligned, the pressurized working fluid (F) flows through the bulkhead 524 and enters a pulse cavity 522, where it is discharged from the pulse cavity 522 as pressure waves 200. The pressure wave propagation 200 and eventual collapse of the bubbles 202 can be transmitted to a target rock surface 204 either in the form of a shock wave 206, or by micro jets 208, depending on the bubble-surface distance. Once cavitation at the rock face begins, fractures are initiated in the rock to create a network of micro-fissures for enhanced heat transfer.

Comparison of the open-close kinetics of the cloned inward rectifier K+ channel IRK1 and its point mutant (Q140E) in the pore region.

PubMed

Guo, L; Kubo, Y

1998-01-01

To test whether a single amino-acid residue at the center of pore region can dictate the difference of open-close kinetics in a steady-state at hyperpolarized potentials among members of the inward K+ channel family, the Q140E mutant of the inward rectifier K+ channel (IRK1) was made and its gating properties were compared with those of IRK1 wild type (Wt) in Xenopus oocytes. The distinct differences were observed only at the single channel level. The open time constant of mutant tau(o)(Q140E) at -80 mV was over ten-fold shorter than that of Wt tau(o)(Wt); in Wt, the closed time distribution was fitted with a sum of two exponentials (c-slow and c-fast), whereas it could be fitted with three exponentials (c-slow, c-fast, and additional c-extrafast) in Q140E. However, the time constant of burst duration of mutant tau(b)(Q140E) was close to tau(o)(Wt) and both showed a similarly strong voltage dependence, and a high sensitivity to pH0 in the absence of Mg02+, indicating that tau(b)(Q140E) is closely related to tau(o)(Wt). These results demonstrated that Q140E shortened the channel openings by acquiring an extra-fast closing state. From the analysis of the effects of cations on both Wt and Q140E, it was suggested that the transition from the open state to this extra-fast closing state was not due to the block by H+ or Mg2+ but possibly by extracellular K+.

New Technological Platform for the National Nuclear Energy Strategy Development

NASA Astrophysics Data System (ADS)

Adamov, E. O.; Rachkov, V. I.

2017-12-01

The paper considers the need to update the development strategy of Russia's nuclear power industry and various approaches to the large-scale nuclear power development. Problems of making decisions on fast neutron reactors and closed nuclear fuel cycle (NFC) arrangement are discussed. The current state of the development of fast neutron reactors and closed NFC technologies in Russia is considered and major problems are highlighted.

First closed-loop visible AO test results for the advanced adaptive secondary AO system for the Magellan Telescope: MagAO's performance and status

NASA Astrophysics Data System (ADS)

Close, Laird M.; Males, Jared R.; Kopon, Derek A.; Gasho, Victor; Follette, Katherine B.; Hinz, Phil; Morzinski, Katie; Uomoto, Alan; Hare, Tyson; Riccardi, Armando; Esposito, Simone; Puglisi, Alfio; Pinna, Enrico; Busoni, Lorenzo; Arcidiacono, Carmelo; Xompero, Marco; Briguglio, Runa; Quiros-Pacheco, Fernando; Argomedo, Javier

2012-07-01

The heart of the 6.5 Magellan AO system (MagAO) is a 585 actuator adaptive secondary mirror (ASM) with <1 msec response times (0.7 ms typically). This adaptive secondary will allow low emissivity and high-contrast AO science. We fabricated a high order (561 mode) pyramid wavefront sensor (similar to that now successfully used at the Large Binocular Telescope). The relatively high actuator count (and small projected ~23 cm pitch) allows moderate Strehls to be obtained by MagAO in the “visible” (0.63-1.05 μm). To take advantage of this we have fabricated an AO CCD science camera called "VisAO". Complete “end-to-end” closed-loop lab tests of MagAO achieve a solid, broad-band, 37% Strehl (122 nm rms) at 0.76 μm (i’) with the VisAO camera in 0.8” simulated seeing (13 cm ro at V) with fast 33 mph winds and a 40 m Lo locked on R=8 mag artificial star. These relatively high visible wavelength Strehls are enabled by our powerful combination of a next generation ASM and a Pyramid WFS with 400 controlled modes and 1000 Hz sample speeds (similar to that used successfully on-sky at the LBT). Currently only the VisAO science camera is used for lab testing of MagAO, but this high level of measured performance (122 nm rms) promises even higher Strehls with our IR science cameras. On bright (R=8 mag) stars we should achieve very high Strehls (>70% at H) in the IR with the existing MagAO Clio2 (λ=1-5.3 μm) science camera/coronagraph or even higher (~98% Strehl) the Mid-IR (8-26 microns) with the existing BLINC/MIRAC4 science camera in the future. To eliminate non-common path vibrations, dispersions, and optical errors the VisAO science camera is fed by a common path advanced triplet ADC and is piggy-backed on the Pyramid WFS optical board itself. Also a high-speed shutter can be used to block periods of poor correction. The entire system passed CDR in June 2009, and we finished the closed-loop system level testing phase in December 2011. Final system acceptance (“pre-ship” review) was passed in February 2012. In May 2012 the entire AO system is was successfully shipped to Chile and fully tested/aligned. It is now in storage in the Magellan telescope clean room in anticipation of “First Light” scheduled for December 2012. An overview of the design, attributes, performance, and schedule for the Magellan AO system and its two science cameras are briefly presented here.

Multiple serial picture presentation with millisecond resolution using a three-way LC-shutter-tachistoscope

PubMed Central

Fischmeister, Florian Ph.S.; Leodolter, Ulrich; Windischberger, Christian; Kasess, Christian H.; Schöpf, Veronika; Moser, Ewald; Bauer, Herbert

2010-01-01

Throughout recent years there has been an increasing interest in studying unconscious visual processes. Such conditions of unawareness are typically achieved by either a sufficient reduction of the stimulus presentation time or visual masking. However, there are growing concerns about the reliability of the presentation devices used. As all these devices show great variability in presentation parameters, the processing of visual stimuli becomes dependent on the display-device, e.g. minimal changes in the physical stimulus properties may have an enormous impact on stimulus processing by the sensory system and on the actual experience of the stimulus. Here we present a custom-built three-way LC-shutter-tachistoscope which allows experimental setups with both, precise and reliable stimulus delivery, and millisecond resolution. This tachistoscope consists of three LCD-projectors equipped with zoom lenses to enable stimulus presentation via a built-in mirror-system onto a back projection screen from an adjacent room. Two high-speed liquid crystal shutters are mounted serially in front of each projector to control the stimulus duration. To verify the intended properties empirically, different sequences of presentation times were performed while changes in optical power were measured using a photoreceiver. The obtained results demonstrate that interfering variabilities in stimulus parameters and stimulus rendering are markedly reduced. Together with the possibility to collect external signals and to send trigger-signals to other devices, this tachistoscope represents a highly flexible and easy to set up research tool not only for the study of unconscious processing in the brain but for vision research in general. PMID:20122963

On the Role of Last Closed Drift Shell Dynamics in Driving Fast Losses and Van Allen Radiation Belt Extinction

NASA Astrophysics Data System (ADS)

Olifer, L.; Mann, I. R.; Morley, S. K.; Ozeke, L. G.; Choi, D.

2018-05-01

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ˜0.5-2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. We compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.

Health Implications of Adults' Eating at and Living near Fast Food or Quick Service Restaurants.

PubMed

Jiao, J; Moudon, A V; Kim, S Y; Hurvitz, P M; Drewnowski, A

2015-07-20

This paper examined whether the reported health impacts of frequent eating at a fast food or quick service restaurant on health were related to having such a restaurant near home. Logistic regressions estimated associations between frequent fast food or quick service restaurant use and health status, being overweight or obese, having a cardiovascular disease or diabetes, as binary health outcomes. In all, 2001 participants in the 2008-2009 Seattle Obesity Study survey were included in the analyses. Results showed eating ⩾2 times a week at a fast food or quick service restaurant was associated with perceived poor health status, overweight and obese. However, living close to such restaurants was not related to negative health outcomes. Frequent eating at a fast food or quick service restaurant was associated with perceived poor health status and higher body mass index, but living close to such facilities was not.

Visible camera imaging of plasmas in Proto-MPEX

NASA Astrophysics Data System (ADS)

Mosby, R.; Skeen, C.; Biewer, T. M.; Renfro, R.; Ray, H.; Shaw, G. C.

2015-11-01

The prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being developed at Oak Ridge National Laboratory (ORNL). This machine plans to study plasma-material interaction (PMI) physics relevant to future fusion reactors. Measurements of plasma light emission will be made on Proto-MPEX using fast, visible framing cameras. The cameras utilize a global shutter, which allows a full frame image of the plasma to be captured and compared at multiple times during the plasma discharge. Typical exposure times are ~10-100 microseconds. The cameras are capable of capturing images at up to 18,000 frames per second (fps). However, the frame rate is strongly dependent on the size of the ``region of interest'' that is sampled. The maximum ROI corresponds to the full detector area, of ~1000x1000 pixels. The cameras have an internal gain, which controls the sensitivity of the 10-bit detector. The detector includes a Bayer filter, for ``true-color'' imaging of the plasma emission. This presentation will exmine the optimized camera settings for use on Proto-MPEX. This work was supported by the US. D.O.E. contract DE-AC05-00OR22725.

A simple, low-cost, versatile CCD spectrometer for plasma spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Den Hartog, D. J.; Holly, D. J.

1996-06-01

The authors have constructed a simple, low-cost CCD spectrometer capable of both high resolution ({Delta}{lambda} {le} 0.015 nm) and large bandpass (110 nm with {Delta}{lambda} {approximately}0.3 nm). These two modes of operation provide two broad areas of capability for plasma spectroscopy. The first major application is measurement of emission line broadening; the second is emission line surveys from the ultraviolet to the near infrared. Measurements have been made on a low-temperature plasma produced by a miniature electrostatic plasma source and the high-temperature plasma in the MST Reversed-Field Pinch. The spectrometer is a modified Jarrell-Ash 0.5 m Ebert-Fastie monochromator. Light ismore » coupled into the entrance slit with a fused silica fiber optic bundle. The exposure time (2 ms minimum) is controlled by a fast electromechanical shutter. The exit plane detector is a compact and robust CCD detector developed for amateur astronomy by Santa Barbara Instrument Group. The CCD detector is controlled and read out by a Macintosh{reg_sign} computer. This spectrometer is sophisticated enough to serve well in a research laboratory, yet is simple and inexpensive enough to be affordable for instructional use.« less

New, high-efficiency ion trap mobility detection system for narcotics and explosives

NASA Astrophysics Data System (ADS)

McGann, William J.; Bradley, V.; Borsody, A.; Lepine, S.

1994-10-01

A new patented Ion Trap Mobility Spectrometer (ITMS) design is presented. Conventional IMS designs typically operate below 0.1% efficiency. This is due primarily to electric field driven, sample ion discharge on a shutter grid. Since 99.9% of the sample ions generated in the reaction region are lost in this discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an `ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a `field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. Many applications for this new detector are now being considered including the detection of narcotics and explosives. Preliminary ion spectra, reduced mobility data and sensitivity data are presented for fifteen narcotics, including cocaine, THC and LSD are reported.

New high-efficiency ion-trap mobility detection system for narcotics

NASA Astrophysics Data System (ADS)

McGann, William J.

1997-02-01

A new patented Ion Trap Mobility Spectrometer design is presented. Conventional IMS designs typically operate below 0.1 percent efficiency. This is due primarily to electric field driven, sample ion discharge on a shutter grid. Since 99.9 percent of the sample ions generated in the reaction region are lost int his discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an 'ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a 'field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. One application for this new detector is now being developed, a portable, hand-held system with switching capability for the detection of drugs and explosives. Preliminary ion spectra and sensitivity data are presented for cocaine and heroin using a hand sniffer configuration.

New high-efficiency ion trap mobility detection system for narcotics and explosives

NASA Astrophysics Data System (ADS)

McGann, William J.; Jenkins, Anthony; Ribiero, K.; Napoli, J.

1994-03-01

A new patented ion trap mobility spectrometer design is presented. Conventional IMS designs typically operate below 0.1% efficiency. This is due primarily to electrical-field-driven, sample ion discharge on a shutter grid. Since 99.9% of the sample ions generated in the reaction region are lost in this discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an `ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a `field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. Many applications for this new detector are now being considered including the detection of narcotics and explosives. Preliminary ion spectra, reduced mobility data and sensitivity data are presented for fifteen narcotics, including cocaine, THC, and LSD are reported.

Optically Activated Exciplex Shutter/Attenuator.

DTIC Science & Technology

radiation of a certain wavelength to excite a bi-molecular exciplex solution. The exciplex solution reacts to a range of radiation wavelengths whereas...optical elements prevent passage of radiation below and above the operative range of an exciplex solution such as anthracene and diethylaniline.

Basal measures of insulin sensitivity and insulin secretion and simplified glucose tolerance tests in dogs.

PubMed

Verkest, K R; Fleeman, L M; Rand, J S; Morton, J M

2010-10-01

There is need for simple, inexpensive measures of glucose tolerance, insulin sensitivity, and insulin secretion in dogs. The aim of this study was to estimate the closeness of correlation between fasting and dynamic measures of insulin sensitivity and insulin secretion, the precision of fasting measures, and the agreement between results of standard and simplified glucose tolerance tests in dogs. A retrospective descriptive study using 6 naturally occurring obese and 6 lean dogs was conducted. Data from frequently sampled intravenous glucose tolerance tests (FSIGTTs) in 6 obese and 6 lean client-owned dogs were used to calculate HOMA, QUICKI, fasting glucose and insulin concentrations. Fasting measures of insulin sensitivity and secretion were compared with MINMOD analysis of FSIGTTs using Pearson correlation coefficients, and they were evaluated for precision by the discriminant ratio. Simplified sampling protocols were compared with standard FSIGTTs using Lin's concordance correlation coefficients, limits of agreement, and Pearson correlation coefficients. All fasting measures except fasting plasma glucose concentration were moderately correlated with MINMOD-estimated insulin sensitivity (|r| = 0.62-0.80; P < 0.03), and those that combined fasting insulin and glucose were moderately closely correlated with MINMOD-estimated insulin secretion (r = 0.60-0.79; P < 0.04). HOMA calculated using the nonlinear formulae had the closest estimated correlation (r = 0.77 and 0.74) and the best discrimination for insulin sensitivity and insulin secretion (discriminant ratio 4.4 and 3.4, respectively). Simplified sampling protocols with half as many samples collected over 3 h had close agreement with the full sampling protocol. Fasting measures and simplified intravenous glucose tolerance tests reflect insulin sensitivity and insulin secretion derived from frequently sampled glucose tolerance tests with MINMOD analysis in dogs. Copyright 2010 Elsevier Inc. All rights reserved.

On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction

DOE PAGES

Olifer, Leonid; Mann, Ian R.; Morley, Steven Karl; ...

2018-04-20

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ~0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, themore » moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. Here, we compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.« less

On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olifer, Leonid; Mann, Ian R.; Morley, Steven Karl

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ~0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, themore » moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. Here, we compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.« less

Advanced development of non-discoloring EVA-based PV encapsulants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holley, W.H.; Galica, J.P.; Argo, S.C.

1996-01-01

The purpose of this investigation was to better define the problem of field yellowing of EVA-based PV encapsulant, through laboratory study of probable chemical mechanisms and the development of stabilization strategies for protecting EVA from discoloration. EVA from fielded modules was analyzed for vinyl acetate content, unsaturation, and additive levels. These test results were then compared to results from Xenon Arc Weather-Ometer aged glass/EVA/glass laminates made in the laboratory. Variables evaluated in Weather-Ometer aged laminates included ``standard-cure`` A9918P EVA, ``fast-cure`` 15295P EVA, low iron glass superstrate containing cerium oxide, and systematic elimination or addition of specific additives. Six significant findingsmore » were revealed: 1) Improved ``standard-cure`` and ``fast-cure`` type EVA encapsulants, formulations X9903P and X15303P, respectively, showed little or no yellowing after extended Weather-Ometer exposure; 2) The use of {open_quote}{open_quote}fast-cure{close_quote}{close_quote} EVA reduced discoloration when compared with {open_quote}{open_quote}standard-cure{close_quote}{close_quote} A9918P EVA; 3) Glass superstrate containing cerium oxide resulted in a reduced rate of EVA discoloration; 4) {open_quote}{open_quote}Fast-cure{close_quote}{close_quote} EVA used with glass superstrate containing cerium oxide showed no visible yellowing after 32 weeks in the Weather-Ometer{emdash}a period estimated to be roughly equivalent to 20{endash}30 years of exposure in the Southwest; 5) Severely discolored EVA samples from the field showed no measurable loss of acetate group and little detectable unsaturation; and 6) EVA encapsulant with a Tefzel cover exhibited no yellowing after extended Weather-Ometer exposure. {copyright} {ital 1996 American Institute of Physics.}« less

GEODSS Present Configuration and Potential

DTIC Science & Technology

2014-06-28

to provide critical metric tracking capacity for deep space catalog maintenance. The follow-up TOS designed as a deployable gap filler in SSN deep...CASTOR) - A RAVEN System In Canada [3]WindowPane Observatory Lanphier Shutter System 2014 Retrieved From: http://windowpaneobservatory.com/ [4]J.N

8. FIRST FLOOR, EAST ROOM, NORTHEAST WALL SHOWING DOORWAYS TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. FIRST FLOOR, EAST ROOM, NORTHEAST WALL SHOWING DOORWAYS TO BOXED WINDER STAIRWAYS, UP ON FAR RIGHT AND DOWN TO RIGHT OF FIREPLACE, WITH SHUTTERS OPEN - High Farm, House, Creek Road, 1 mile West of Easton Road, Pipersville, Bucks County, PA

Photography Foundations: The Student Photojournalist.

ERIC Educational Resources Information Center

Glowacki, Joseph W.

Designed to aid student publications photographers in taking effective photographs, this publication provides discussions relating to the following areas: a publications photographer's self-image, the camera, camera handling, using the adjustable camera, the light meter, depth of field, shutter speeds and action pictures, lenses for publications…

22. Historic American Buildings Survey, Stanley P. Mixon, Photographer September ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. Historic American Buildings Survey, Stanley P. Mixon, Photographer September 11, 1940 INTERIOR, DETAIL OF END GABLE WINDOW IN ATTIC (SMOKE ROOM) WITH OLD WOODEN SHUTTER, SHOWING PIVOTED SWINGING FRAME. - Fort Zeller, Mill Creek (Millcreek Township), Newmanstown, Lebanon County, PA

CAVE WINDOW

DOEpatents

Levenson, M.

1960-10-25

A cave window is described. It is constructed of thick glass panes arranged so that interior panes have smaller windowpane areas and exterior panes have larger areas. Exterior panes on the radiation exposure side are remotely replaceable when darkened excessively. Metal shutters minimize exposure time to extend window life.

Photoswitching of ferroelectric liquid crystals using chiral thioindigo dopants: The development of a photochemical switch hitter.

PubMed

Lemieux, Robert P

2004-01-01

By virtue of its spontaneous polarization (PS), a ferroelectric SmC* liquid crystal can be switched between two states corresponding to opposite molecular tilt orientations using an electric field, thus producing an ON-OFF light shutter between crossed polarizers. Considerable efforts have been made over the past decade to develop photonic FLC light shutters because of their potential uses in dynamic holography and optical data storage. The ON-OFF switching of a FLC light shutter can be triggered by light via a photoinversion of PS using a photochromic dopant. The spontaneous polarization is a chiral bulk property that can be left-handed (negative) or right-handed (positive), depending on the absolute configuration of the chiral component of the SmC* phase. In the approach described herein, the magnitude of PS is modulated via the photoisomerization of a chiral thioindigo dopant that undergoes a large increase in transverse dipole moment upon trans-cis photoisomerization. The sign of PS is photoinverted using an "ambidextrous" thioindigo dopant containing a chiral 2-octyloxy side chain that is coupled to the thioindigo core and induces a positive PS, and a chiral 2,3-difluorooctyloxy side chain that is decoupled from the core and induces a negative PS. In the trans form, the 2,3-difluorooctyloxy side chain predominates and the net PS induced by the dopant is negative. However, upon trans-cis-photoisomerization, the increase in transverse dipole moment of the 2-octyloxy/thioindigo unit raises its induced PS over that of the decoupled 2,3-difluorooctyloxy side chain, and thus inverts the net sign of PS induced by the dopant from negative to positive. Copyright 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Adiabatic model of field reversal by fast ions in an axisymmetric open trap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsidulko, Yu. A., E-mail: tsidulko@mail.ru

2016-06-15

A model of field reversal by fast ions has been developed under the assumption of preservation of fast-ion adiabatic invariants. Analytical solutions obtained in the approximation of a narrow fast-ion layer and numerical solutions to the evolutionary problem are presented. The solutions demonstrate the process of formation of a field reversed configuration with parameters close to those of the planned experiment.

Health Implications of Adults' Eating at and Living near Fast Food or Quick Service Restaurants

PubMed Central

Jiao, J; Moudon, A V; Kim, S Y; Hurvitz, P M; Drewnowski, A

2015-01-01

Background: This paper examined whether the reported health impacts of frequent eating at a fast food or quick service restaurant on health were related to having such a restaurant near home. Methods: Logistic regressions estimated associations between frequent fast food or quick service restaurant use and health status, being overweight or obese, having a cardiovascular disease or diabetes, as binary health outcomes. In all, 2001 participants in the 2008–2009 Seattle Obesity Study survey were included in the analyses. Results: Results showed eating ⩾2 times a week at a fast food or quick service restaurant was associated with perceived poor health status, overweight and obese. However, living close to such restaurants was not related to negative health outcomes. Conclusions: Frequent eating at a fast food or quick service restaurant was associated with perceived poor health status and higher body mass index, but living close to such facilities was not. PMID:26192449

Laser beam control device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, H.L.

1976-01-06

The shutter and beam expander for diverting the output of a high power laser into an absorption body comprises a onepiece metallic structure having a convex spherically shaped portion adapted to be moved into the beam path for simultaneously reflecting and expanding the beam into energy absorption material.

Guidebook to School Publications Photography.

ERIC Educational Resources Information Center

Glowacki, Joseph W.

This guidebook for school publications photographers discusses both the self-image of the publications photographer and various aspects of photography, including components of the camera, shutter speed and action pictures, light meters, handling cameras, lenses, developing film, pushing film beyond the emulsion-speed rating recommended by the…

Sustaining Green School Momentum

ERIC Educational Resources Information Center

Kennedy, Mike

2012-01-01

For several years, schools and universities have been battered by a sputtering economy that on many campuses has brought about slashed budgets, curtailed programs, shuttered facilities and terminated employees. But throughout the gloomy financial conditions, one of the bright spots for education institutions is the continued growing embrace of…

3. Historic American Buildings Survey James F. and Jean B. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Historic American Buildings Survey James F. and Jean B. O'Gorman, Photographers October 1963 ORIGINAL MANTELPIECE AND WINDOW SHUTTERS, FIRST FLOOR Gift of James F. and Jean B. O'Gorman - Stephen Higginson Jr. House, 7 Kirkland Street, Cambridge, Middlesex County, MA

Switching Matrix For Optical Signals

NASA Technical Reports Server (NTRS)

Grove, Charles H.

1990-01-01

Proposed matrix of electronically controlled shutters switches signals in optical fibers between multiple input and output channels. Size, weight, and power consumption reduced. Device serves as building block for small, low-power, broad-band television- and data-signal-switching systems providing high isolation between nominally disconnected channels.

Development of a PET cyclotron based irradiation setup for proton radiobiology

NASA Astrophysics Data System (ADS)

Ghithan, Sharif; Crespo, Paulo; do Carmo, S. J. C.; Ferreira Marques, Rui; Fraga, F. A. F.; Simões, Hugo; Alves, Francisco; Rachinhas, P. J. B. M.

2015-02-01

An out-of-yoke irradiation setup using the proton beam from a cyclotron that ordinary produces radioisotopes for positron emission tomography (PET) has been developed, characterized, calibrated and validated. The current from a 20 μm thick aluminum transmission foil is readout by home-made transimpedance electronics, providing online dose information. The main monitoring variables, delivered in real-time, include beam current, integrated charge and dose rate. Hence the dose and integrated current delivered at a given instant to an experimental setup can be computer-controlled with a shutter. In this work, we report on experimental results and Geant4 simulations of a setup which exploits for the first time the 18 MeV proton beam from a PET cyclotron to irradiate a selected region of a target using the developed irradiation system. By using this system, we are able to deliver a homogeneous beam on targets with 18 mm diameter, allowing to achieve the controlled irradiation of cell cultures located in biological multi-well dishes of 16 mm diameter. We found that the magnetic field applied inside the cyclotron plays a major role for achieving the referred to homogeneity. The quasi-Gaussian curve obtained by scanning the magnet current and measuring the corresponding dose rate must be measured before any irradiation procedure, with the shutter closed. At the optimum magnet current, which corresponds to the center of the Gaussian, a homogenous dose is observed over the whole target area. Making use of a rotating disk with a slit of 0.5 mm at a radius of 150 mm, we could measure dose rates on target ranging from 500 mGy/s down to 5 mGy/s. For validating the developed irradiation setup, several Gafchromic® EBT2 films were exposed to different values of dose. The absolute dose in the irradiated films were assessed in the 2D film dosimetry system of the Department of Radiotherapy of Coimbra University Hospital Center with a precision better than 2%. In the future, we plan to irradiate small animals, cell cultures, or other materials or samples.

Data Processing for the Space-Based Desis Hyperspectral Sensor

NASA Astrophysics Data System (ADS)

Carmona, E.; Avbelj, J.; Alonso, K.; Bachmann, M.; Cerra, D.; Eckardt, A.; Gerasch, B.; Graham, L.; Günther, B.; Heiden, U.; Kerr, G.; Knodt, U.; Krutz, D.; Krawcyk, H.; Makarau, A.; Miller, R.; Müller, R.; Perkins, R.; Walter, I.

2017-05-01

The German Aerospace Center (DLR) and Teledyne Brown Engineering (TBE) have established a collaboration to develop and operate a new space-based hyperspectral sensor, the DLR Earth Sensing Imaging Spectrometer (DESIS). DESIS will provide spacebased hyperspectral data in the VNIR with high spectral resolution and near-global coverage. While TBE provides the platform and infrastructure for operation of the DESIS instrument on the International Space Station, DLR is responsible for providing the instrument and the processing software. The DESIS instrument is equipped with novel characteristics for an imaging spectrometer such high spectral resolution (2.55 nm), a mirror pointing unit or a CMOS sensor operated in rolling shutter mode. We present here an overview of the DESIS instrument and its processing chain, emphasizing the effect of the novel characteristics of DESIS in the data processing and final data products. Furthermore, we analyse in more detail the effect of the rolling shutter on the DESIS data and possible mitigation/correction strategies.

Measuring frequency of one-dimensional vibration with video camera using electronic rolling shutter

NASA Astrophysics Data System (ADS)

Zhao, Yipeng; Liu, Jinyue; Guo, Shijie; Li, Tiejun

2018-04-01

Cameras offer a unique capability of collecting high density spatial data from a distant scene of interest. They can be employed as remote monitoring or inspection sensors to measure vibrating objects because of their commonplace availability, simplicity, and potentially low cost. A defect of vibrating measurement with the camera is to process the massive data generated by camera. In order to reduce the data collected from the camera, the camera using electronic rolling shutter (ERS) is applied to measure the frequency of one-dimensional vibration, whose frequency is much higher than the speed of the camera. Every row in the image captured by the ERS camera records the vibrating displacement at different times. Those displacements that form the vibration could be extracted by local analysis with sliding windows. This methodology is demonstrated on vibrating structures, a cantilever beam, and an air compressor to identify the validity of the proposed algorithm. Suggestions for applications of this methodology and challenges in real-world implementation are given at last.

Tachistoscopic exposure and masking of real three-dimensional scenes

PubMed Central

Pothier, Stephen; Philbeck, John; Chichka, David; Gajewski, Daniel A.

2010-01-01

Although there are many well-known forms of visual cues specifying absolute and relative distance, little is known about how visual space perception develops at small temporal scales. How much time does the visual system require to extract the information in the various absolute and relative distance cues? In this article, we describe a system that may be used to address this issue by presenting brief exposures of real, three-dimensional scenes, followed by a masking stimulus. The system is composed of an electronic shutter (a liquid crystal smart window) for exposing the stimulus scene, and a liquid crystal projector coupled with an electromechanical shutter for presenting the masking stimulus. This system can be used in both full- and reduced-cue viewing conditions, under monocular and binocular viewing, and at distances limited only by the testing space. We describe a configuration that may be used for studying the microgenesis of visual space perception in the context of visually directed walking. PMID:19182129

Laser additive manufacturing of 3D meshes for optical applications.

PubMed

Essa, Khamis; Sabouri, Aydin; Butt, Haider; Basuny, Fawzia Hamed; Ghazy, Mootaz; El-Sayed, Mahmoud Ahmed

2018-01-01

Selective laser melting (SLM) is a widely used additive manufacturing process that can be used for printing of intricate three dimensional (3D) metallic structures. Here we demonstrate the fabrication of titanium alloy Ti-6Al-4V alloy based 3D meshes with nodally-connected diamond like unit cells, with lattice spacing varying from 400 to 1000 microns. A Concept Laser M2 system equipped with laser that has a wavelength of 1075 nm, a constant beam spot size of 50μm and maximum power of 400W was used to manufacture the 3D meshes. These meshes act as optical shutters / directional transmitters and display interesting optical properties. A detailed optical characterisation was carried out and it was found that these structures can be optimised to act as scalable rotational shutters with high efficiencies and as angle selective transmission screens for protection against unwanted and dangerous radiations. The efficiency of fabricated lattice structures can be increased by enlarging the meshing size.

Laser additive manufacturing of 3D meshes for optical applications

PubMed Central

Essa, Khamis; Sabouri, Aydin; Butt, Haider; Basuny, Fawzia Hamed; Ghazy, Mootaz

2018-01-01

Selective laser melting (SLM) is a widely used additive manufacturing process that can be used for printing of intricate three dimensional (3D) metallic structures. Here we demonstrate the fabrication of titanium alloy Ti–6Al–4V alloy based 3D meshes with nodally-connected diamond like unit cells, with lattice spacing varying from 400 to 1000 microns. A Concept Laser M2 system equipped with laser that has a wavelength of 1075 nm, a constant beam spot size of 50μm and maximum power of 400W was used to manufacture the 3D meshes. These meshes act as optical shutters / directional transmitters and display interesting optical properties. A detailed optical characterisation was carried out and it was found that these structures can be optimised to act as scalable rotational shutters with high efficiencies and as angle selective transmission screens for protection against unwanted and dangerous radiations. The efficiency of fabricated lattice structures can be increased by enlarging the meshing size. PMID:29414982

Characteristics of biomass ashes from different materials and their ameliorative effects on acid soils.

PubMed

Shi, Renyong; Li, Jiuyu; Jiang, Jun; Mehmood, Khalid; Liu, Yuan; Xu, Renkou; Qian, Wei

2017-05-01

The chemical characteristics, element contents, mineral compositions, and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied depending on the source biomass material. An increase in the concrete shuttering contents in the biomass materials led to higher alkalinity, and higher Ca and Mg levels in biomass ashes, which made them particularly good at ameliorating effects on soil acidity. However, heavy metal contents, such as Cr, Cu, and Zn in the ashes, were relatively high. The incorporation of all ashes increased soil pH, exchangeable base cations, and available phosphorus, but decreased soil exchangeable acidity. The application of the ashes from biomass materials with a high concrete shuttering content increased the soil available heavy metal contents. Therefore, the biomass ashes from wood and crop residues with low concrete contents were the better acid soil amendments. Copyright © 2016. Published by Elsevier B.V.

Optimization of the open-loop liquid crystal adaptive optics retinal imaging system

NASA Astrophysics Data System (ADS)

Kong, Ningning; Li, Chao; Xia, Mingliang; Li, Dayu; Qi, Yue; Xuan, Li

2012-02-01

An open-loop adaptive optics (AO) system for retinal imaging was constructed using a liquid crystal spatial light modulator (LC-SLM) as the wavefront compensator. Due to the dispersion of the LC-SLM, there was only one illumination source for both aberration detection and retinal imaging in this system. To increase the field of view (FOV) for retinal imaging, a modified mechanical shutter was integrated into the illumination channel to control the size of the illumination spot on the fundus. The AO loop was operated in a pulsing mode, and the fundus was illuminated twice by two laser impulses in a single AO correction loop. As a result, the FOV for retinal imaging was increased to 1.7-deg without compromising the aberration detection accuracy. The correction precision of the open-loop AO system was evaluated in a closed-loop configuration; the residual error is approximately 0.0909λ (root-mean-square, RMS), and the Strehl ratio ranges to 0.7217. Two subjects with differing rates of myopia (-3D and -5D) were tested. High-resolution images of capillaries and photoreceptors were obtained.

High Contrast Programmable Field Masks for JWST NIRSpec

NASA Technical Reports Server (NTRS)

Kutyrev, Alexander S.

2008-01-01

Microshutter arrays are one of the novel technologies developed for the James Webb Space Telescope (JWST). It will allow Near Infrared Spectrometer (NIRSpec) to acquire spectra of hundreds of objects simultaneously therefore increasing its efficiency tremendously. We have developed these programmable arrays that are based on Micro-Electro Mechanical Structures (MEMS) technology. The arrays are 2D addressable masks that can operate in cryogenic environment of JWST. Since the primary JWST science requires acquisition of spectra of extremely faint objects, it is important to provide very high contrast of the open to closed shutters. This high contrast is necessary to eliminate any possible contamination and confusion in the acquired spectra by unwanted objects. We have developed and built a test system for the microshutter array functional and optical characterization. This system is capable of measuring the contrast of the microshutter array both in visible and infrared light of the NIRSpec wavelength range while the arrays are in their working cryogenic environment. We have measured contrast ratio of several microshutter arrays and demonstrated that they satisfy and in many cases far exceed the NIRSpec contrast requirement value of 2000.

Thermal-infrared imager TIR on Hayabusa2: Result of ground calibration

NASA Astrophysics Data System (ADS)

Okada, T.; Fukuhara, T.; Tanaka, S.; Taguchi, M.; Arai, T.; Imamura, T.; Senshu, H.; Sekiguchi, T.; Ogawa, Y.; Demura, H.; Sakatani, N.; Horikawa, Y.; Helbert, J.; Mueller, T.; Hagermann, A.; H. TIR-Team

2014-07-01

Thermal-infrared imager TIR on Hayabusa2 will image C-class NEA (162173)1999JU3 in 8-12 micrometer band. TIR observation is not only for scientific investigation of asteroid thermo-physical properties, but also for assessment of landing site selection and safety descent operation. Hayabusa2 is the follow-on mission after Hayabusa that accomplished the first asteroid sample-return in 2010. Hayabusa2 is primarily an asteroid sample-return mission, but remote sensing of the asteroid is also essential to understand the global nature of asteroid, complementary to returned samples. Active impact experiment using SCI (Small Carry-on Impactor) and surface measurements using MASCOT lander which carries camera, NIR imaging microscope, radiator, and magnetometer, as well as hopping rover MINERVA are also planned in this mission. A thermal-infrared imager is to image the surface temperature profile and its temporal variation by asteroid rotation. TIR adopts a non- cooled bolometer array NEC 320A with 328×248 effective pixels. Its fields of view covers 16°×12° with 0.05° per pixel. The image can be taken at 60 Hz, and summation onboard can be set from 1 to 128 to improve signal-to-background ratio. The imaging is interlaced with the shutter open and close. The subtraction of shutter-close image (bias data) from shutter-open image (biased image) produces the realistic thermal images. To improve more accurate data in radiation intensity, those realistic thermal images can be summed by onboard software. Data compression is also conducted by onboard software[1]. TIR is based on LIR on Akatsuki Venus climate orbiter [2]. We know something about C-type meteorites but little about C-class asteroids. We know little about asteroid 1999JU3 but it is considered as something like low-dense and huge-cratered as asteroid 253 Mathilde, or like rubble-piled, sedimented small asteroid 25143 Itokawa. To investigate the nature of asteroid and its formation processes, thermo-physical properties of boulders or materials inside huge crates are important targets to observe. Evident thermal measurements are conducted to compare them with thermal model for ground observation, and to investigate Yarkovsky or YORP effects. If the orbiting satellites or dust clouds exist at the surroundings, asteroid mass or dust properties will be determined. Cooperative observation with radiometer on MASCOT is also important to determine the thermo-physical properties precisely. We conducted radiometric and geometric calibration for TIR. We use the cavity black-body and oil-bath based black-body plates for calibration at higher temperature from 25 to 150 °C. We also use the black-body plate inside the vacuum chamber for lower temperature from -40 to +50 °C. Both of appratuses share the temperature region from 25 to 50 °C. For geometrical correction, collimator is used measure the square-shaped target. For cross-calibration, the same targets are used for other instruments: 30 cm diameter serpentine target plate with heater is shared with MARA radiometer on MASCOT, and the same meteorite samples (Murchison CM2 meteorites, Murray CM2 meteorites) are shared with NIRS3 spectrometer and ONC camera. The landscape and the walls of test sites were imaged for demonstration. TIR is able to measure the surface temperature from -40 to 150 °C at the central region of images (a little wider range but less resolution at non-central region). The absolute temperature is less than 2 °C, and the resolution (NETD) is less than 0.3 °C for most of conditions. TIR is well calibrated thermal-infrared imager to take thermal images of asteroid and investigate its thermo-physical properties. This type of instruments will be used in other future missions for scientific and operational purposes.

High-Voltage Power Supply With Fast Rise and Fall Times

NASA Technical Reports Server (NTRS)

Bearden, Douglas B.; Acker, Richard M.; Kapuslka, Robert E.

2007-01-01

A special-purpose high-voltage power supply can be electronically switched on and off with fast rise and fall times, respectively. The output potential is programmable from 20 to 1,250 V. An output current of 50 A can be sustained at 1,250 V. The power supply was designed specifically for electronically shuttering a microchannel plate in an x-ray detector that must operate with exposure times as short as 1 ms. The basic design of the power supply is also adaptable to other applications in which there are requirements for rapid slewing of high voltages. The power-supply circuitry (see figure) includes a preregulator, which is used to program the output at 1/30 of the desired output potential. After the desired voltage has been set, the outputs of a pulse width modulator (PWM) are enabled and used to amplify the preregulator output potential by 30. The amplification is achieved by use of two voltage doublers with a transformer that has two primary and two secondary windings. A resistor is used to limit the current by controlling the drive voltage of two field-effect transistors (FETs) during turn-on of the PWM. A pulse transformer is used to turn on four FETs to short-circuit four output capacitors when the outputs of the PWM have been disabled. The most notable aspects of the performance of the power supply are a rise time of only 80 s and a fall time of only 60 s at a load current of 50 A or less. Another notable aspect is that the application of a 0-to-5-V square wave to a shutdown pin of the PWM causes the production of a 0-to-1,250-V square wave at the output terminals.

A dual-beam actinic light source for photosynthesis research

NASA Technical Reports Server (NTRS)

Margozzi, A. P.; Henderson, M. E.

1972-01-01

Simulation of photosynthetic process in plants is accomplished by using two separate and identical optical channels that provide independently adjustable wavelengths (filters), shutter sequencing, and control intensity of illumination. In addition to experiments using electron paramagnetic resonance spectroscopy, system may be applicable to other types of research in photosynthetic field.

46 CFR 45.117 - Freeing port area: General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES... on the freeboard deck and on the raised quarterdeck must be at least as great as A in the following... bearings of noncorrodible material. If shutters are fitted with securing appliances, these appliances must...

46 CFR 45.117 - Freeing port area: General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES... on the freeboard deck and on the raised quarterdeck must be at least as great as A in the following... bearings of noncorrodible material. If shutters are fitted with securing appliances, these appliances must...

46 CFR 45.117 - Freeing port area: General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES... on the freeboard deck and on the raised quarterdeck must be at least as great as A in the following... bearings of noncorrodible material. If shutters are fitted with securing appliances, these appliances must...

46 CFR 45.117 - Freeing port area: General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES... on the freeboard deck and on the raised quarterdeck must be at least as great as A in the following... bearings of noncorrodible material. If shutters are fitted with securing appliances, these appliances must...

46 CFR 45.117 - Freeing port area: General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES... on the freeboard deck and on the raised quarterdeck must be at least as great as A in the following... bearings of noncorrodible material. If shutters are fitted with securing appliances, these appliances must...

Schools in the New Economy

ERIC Educational Resources Information Center

Kennedy, Mike

2011-01-01

Schools and universities across the United States have been forced to cope with a grim financial situation that has left them without adequate resources. Administrators are cutting programs, reining in salaries and jettisoning employees to keep operating budgets in line. Education institutions also have had to shutter facilities or postpone,…

14 CFR 27.1305 - Powerplant instruments.

Code of Federal Regulations, 2013 CFR

2013-01-01

... with § 27.955. (n) A gas temperature indicator for each turbine engine. (o) Means to enable the pilot... temperature indicator, for each— (1) Air cooled engine; (2) Rotorcraft with cooling shutters; and (3... condition with respect to cooling. (c) A fuel pressure indicator, for each pump-fed engine. (d) A fuel...

14 CFR 27.1305 - Powerplant instruments.

Code of Federal Regulations, 2014 CFR

2014-01-01

... with § 27.955. (n) A gas temperature indicator for each turbine engine. (o) Means to enable the pilot... temperature indicator, for each— (1) Air cooled engine; (2) Rotorcraft with cooling shutters; and (3... condition with respect to cooling. (c) A fuel pressure indicator, for each pump-fed engine. (d) A fuel...

14 CFR 27.1305 - Powerplant instruments.

Code of Federal Regulations, 2011 CFR

2011-01-01

... with § 27.955. (n) A gas temperature indicator for each turbine engine. (o) Means to enable the pilot... temperature indicator, for each— (1) Air cooled engine; (2) Rotorcraft with cooling shutters; and (3... condition with respect to cooling. (c) A fuel pressure indicator, for each pump-fed engine. (d) A fuel...

14 CFR 27.1305 - Powerplant instruments.

Code of Federal Regulations, 2012 CFR

2012-01-01

... with § 27.955. (n) A gas temperature indicator for each turbine engine. (o) Means to enable the pilot... temperature indicator, for each— (1) Air cooled engine; (2) Rotorcraft with cooling shutters; and (3... condition with respect to cooling. (c) A fuel pressure indicator, for each pump-fed engine. (d) A fuel...

Evaluation of isotopic composition of fast reactor core in closed nuclear fuel cycle

NASA Astrophysics Data System (ADS)

Tikhomirov, Georgy; Ternovykh, Mikhail; Saldikov, Ivan; Fomichenko, Peter; Gerasimov, Alexander

2017-09-01

The strategy of the development of nuclear power in Russia provides for use of fast power reactors in closed nuclear fuel cycle. The PRORYV (i.e. «Breakthrough» in Russian) project is currently under development. Within the framework of this project, fast reactors BN-1200 and BREST-OD-300 should be built to, inter alia, demonstrate possibility of the closed nuclear fuel cycle technologies with plutonium as a main source of energy. Russia has a large inventory of plutonium which was accumulated in the result of reprocessing of spent fuel of thermal power reactors and conversion of nuclear weapons. This kind of plutonium will be used for development of initial fuel assemblies for fast reactors. The closed nuclear fuel cycle concept of the PRORYV assumes self-supplied mode of operation with fuel regeneration by neutron capture reaction in non-enriched uranium, which is used as a raw material. Operating modes of reactors and its characteristics should be chosen so as to provide the self-sufficient mode by using of fissile isotopes while refueling by depleted uranium and to support this state during the entire period of reactor operation. Thus, the actual issue is modeling fuel handling processes. To solve these problems, the code REPRORYV (Recycle for PRORYV) has been developed. It simulates nuclide streams in non-reactor stages of the closed fuel cycle. At the same time various verified codes can be used to evaluate in-core characteristics of a reactor. By using this approach various options for nuclide streams and assess the impact of different plutonium content in the fuel, fuel processing conditions, losses during fuel processing, as well as the impact of initial uncertainties on neutron-physical characteristics of reactor are considered in this study.

Initiation of long, free-standing z discharges by CO2 laser gas heating

NASA Astrophysics Data System (ADS)

Niemann, C.; Tauschwitz, A.; Penache, D.; Neff, S.; Knobloch, R.; Birkner, R.; Presura, R.; Hoffmann, D. H. H.; Yu, S. S.; Sharp, W. M.

2002-01-01

High current discharge channels can neutralize both current and space charge of very intense ion beams. Therefore, they are considered an interesting solution for final focus and beam transport in a heavy ion beam fusion reactor. At the Gesellschaft für Schwerionenforschung accelerator facility, 50 cm long, free-standing discharge channels were created in a 60 cm diameter metallic chamber. Discharges with currents of 45 kA in 2 to 25 mbar ammonia (NH3) gas are initiated by a CO2 laser pulse along the channel axis before the capacitor bank is triggered. Resonant absorption of the laser, tuned to the v2 vibration of the ammonia molecule, causes strong gas heating. Subsequent expansion and rarefaction of the gas prepare the conditions for a stable discharge to fulfill the requirements for ion beam transport. The influence of an electric prepulse on the high current discharge was investigated. This article describes the laser-gas interaction and the discharge initiation mechanism. We found that channels are magnetohydrodynamic stable up to currents of 45 kA, measured by fast shutter and streak imaging techniques. The rarefaction of the laser heated gas is studied by means of a one-dimensional Lagrangian fluid code (CYCLOPS) and is identified as the dominant initiation mechanism of the discharge.

Attitudinal Determinants of Turkish Diabetic Patients and Physicians About Ramadan Fasting.

PubMed

Savaş, Esen

2018-02-01

The aim of the study was to investigate whether fasting diabetic patients received recommendations regarding fasting or they consulted the physicians before and during Ramadan along with the affect of sociodemographic factors on Ramadan fasting. The study was conducted on 190 diabetic patients after 2014 Ramadan Month. A questionnaire was collected regarding sociodemographic characteristics, diabetes-related characteristics, recommendations of physicians, and behavioral patterns of fasting patients. Overall 41.6% of diabetic patients fasted during Ramadan. 83.5% of them did not go to physician during Ramadan, 65.8% did not consult physicians before fasting and 12.7% were informed by physicians regarding fasting and diabetes. Result of the study was that both physicians and patients were not well aware of the importance of pre-Ramadan education and close follow-up during fasting.

Challenging Ronald: McDonald versus McDonald's.

PubMed

McDonald, David

2012-02-01

Obesity is the most prevalent health condition affecting first world children in 2011. This article recounts a campaign that opposed the construction of a fast food outlet in close proximity to a large school complex. The epidemiologic evidence that there is a negative health impact on children that attend schools close to fast food outlets is reiterated. There is an urgent need for planning laws to be modernised to reflect that evidence. © 2011 The Author. Journal of Paediatrics and Child Health © 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Fast-Track Cleanup at Closing DoD Installations

EPA Pesticide Factsheets

The Fast-Track Cleanup program strives to make parcels available for reuse as quickly as possible by the transfer of uncontaminated or remediated parcels, the lease of contaminated parcels where cleanup is underway, or the 'early transfer' of contaminated property undergoing cleanup.

Eddy covariance measurements in complex terrain with a new fast response, closed-path analyzer: spectral characteristics and cross-system comparisons

EPA Science Inventory

In recent years, a new class of enclosed, closed-path gas analyzers suitable for eddy covariance applications has come to market, designed to combine the advantages of traditional closed-path systems (small density corrections, good performance in poor weather) and open-path syst...

Tunable liquid crystal photonic devices

NASA Astrophysics Data System (ADS)

Fan, Yun-Hsing

2005-07-01

Liquid crystal (LC)-based adaptive optics are important for information processing, optical interconnections, photonics, integrated optics, and optical communications due to their tunable optical properties. In this dissertation, we describe novel liquid crystal photonic devices. In Chap. 3, we demonstrate a novel electrically tunable-efficiency Fresnel lens which is devised for the first time using nanoscale PDLC. The tunable Fresnel lens is very desirable to eliminate the need of external spatial light modulator. The nanoscale LC devices are polarization independent and exhibit a fast response time. Because of the small droplet sizes, the operating voltage is higher than 100 Vrms. To lower the driving voltage, in Chap. 2 and Chap. 3, we have investigated tunable Fresnel lens using polymer-network liquid crystal (PNLC) and phase-separated composite film (PSCOF). The operating voltage is below 12 Vrms. The PNLC and PSCOF devices are polarization dependent. To overcome this shortcoming, stacking two cells with orthogonal alignment directions is a possibility. Using PNLC, we also demonstrated LC blazed grating. The diffraction efficiency of these devices is continuously controlled by the electric field. We also develop a system with continuously tunable focal length. A conventional mechanical zooming system is bulky and power hungry. In Chap. 4, we developed an electrically tunable-focus flat LC spherical lens and microlens array. A huge tunable range from 0.6 m to infinity is achieved by the applied voltage. In Chap. 5, we describe a LC microlens array whose focal length can be switched from positive to negative by the applied voltage. The fast response time feature of our LC microlens array will be very helpful in developing 3-D animated images. In Chap. 6, we demonstrate polymer network liquid crystals for switchable polarizers and optical shutters. The use of dual-frequency liquid crystal and special driving scheme leads to a sub-millisecond response time. In Chap. 7, for the first time, we demonstrate a fast-response and scattering-free homogeneously-aligned PNLC light modulator. The PNLC response time is ˜300x faster than that of a pure LC mixture. The PNLC cell also holds promise for mid and long infrared applications where response time is a critical issue.

Apollo 8 Mission image,Earth and Lunar Horizon

NASA Image and Video Library

1968-12-21

Apollo 8,Earth and Lunar Horizon. Image taken on Revolution 10 during Transearth Injection (TEI). Original Film Magazine was labeled D. Camera Data: 70mm Hasselblad. Lens: 80mm; F-Stop: F/11; Shutter Speed: 1/250 second. Film Type: Kodak SO-3400 Black and White,ASA 40. Flight Date: December 21-27,1968.

Hot hollow cathode gun assembly

DOEpatents

Zeren, J.D.

1983-11-22

A hot hollow cathode deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, the hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

Vacuum vapor deposition gun assembly

DOEpatents

Zeren, Joseph D.

1985-01-01

A vapor deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, a hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

Physics on Tap

ERIC Educational Resources Information Center

Wheeler, Andrew P. S.

2012-01-01

This article aims to describe how to visualize surface tension effects in liquid jets. A simple experiment is proposed using the liquid jet flow from a mains water tap/faucet. Using a modern digital camera with a high shutter speed, it is possible to visualize the instabilities (capillary waves) that form within the jet due to the action of…

Antioch Rises from the Ashes

ERIC Educational Resources Information Center

Biemiller, Lawrence

2012-01-01

This article features Antioch College, an old campus with a new future. With no tuition, no accreditation, and a mostly empty campus, the college is making a slow and careful start. Reopening a college that had been shuttered for three years certainly qualifies--especially a college with a rich history that, at this point, is equal parts blessing…

An automatic lightning detection and photographic system

NASA Technical Reports Server (NTRS)

Wojtasinski, R. J.; Holley, L. D.; Gray, J. L.; Hoover, R. B.

1973-01-01

Conventional 35-mm camera is activated by an electronic signal every time lightning strikes in general vicinity. Electronic circuit detects lightning by means of antenna which picks up atmospheric radio disturbances. Camera is equipped with fish-eye lense, automatic shutter advance, and small 24-hour clock to indicate time when exposures are made.

Debates over School Shutdowns Heating Up

ERIC Educational Resources Information Center

Zubrzycki, Jaclyn

2012-01-01

As school closures are increasingly used as a remedy to budget woes and a solution to failing schools in many cities, debates are intensifying about their effect on student performance and well-being, on district finances, and on communities and the processes districts use to choose which schools will be shuttered. Student and parent groups in…

Basic Photography; A Primer for Professionals. Second Edition.

ERIC Educational Resources Information Center

Langford, Michael J.

In this textbook, which was written for the professional photography student, both photographic theory and practice are thoroughly explained. The author examines the principles of light and the properties of lenses and gives a detailed evaluation of camera movement, camera shutters, and the camera as a whole. He outlines the manufacture and…

Permanent Visual Change Associated with Punctate Foveal Lesions,

DTIC Science & Technology

1986-03-01

Resources, National Research Council. This material has been reviewed by Letterman Army Institute of Research and there is no objection to its presentation...OrIDist swia SPEC, 4 -Zwick et al .4.D DETECTOR MIRROR I DIFFUSER FRONT SURFACE OSLD ND MIRROR LASER SHUTTER 3 REAM No FILTERr-: SPLIT7ER L3 C

Is German Necessary? Nein, Says One University

ERIC Educational Resources Information Center

Wasley, Paula

2008-01-01

When the University of Southern California announced that it would shutter its tiny German department, the outcry was out of proportion to the handful of faculty members and students directly affected by the move. In addition to students who advertised their dismay on Facebook and faculty members who complained that their efforts to bolster the…

Polarization digital holographic microscopy using low-cost liquid crystal polarization rotators

NASA Astrophysics Data System (ADS)

Dovhaliuk, Rostyslav Yu

2018-02-01

Polarization imaging methods are actively used to study anisotropic objects. A number of methods and systems, such as imaging polarimeters, were proposed to measure the state of polarization of light that passed through the object. Digital holographic and interferometric approaches can be used to quantitatively measure both amplitude and phase of a wavefront. Using polarization modulation optics, the measurement capabilities of such interference-based systems can be extended to measure polarization-dependent parameters, such as phase retardation. Different kinds of polarization rotators can be used to alternate the polarization of a reference beam. Liquid crystals are used in a rapidly increasing number of different optoelectronic devices. Twisted nematic liquid crystals are widely used as amplitude modulators in electronic displays and light valves or shutter glass. Such devices are of particular interest for polarization imaging, as they can be used as polarization rotators, and due to large-scale manufacturing have relatively low cost. A simple Mach-Zehnder polarized holographic setup that uses modified shutter glass as a polarization rotator is demonstrated. The suggested approach is experimentally validated by measuring retardation of quarter-wave film.

Determination of the solar transmittance for the translucent shutter with PCM in liquid and solid state

NASA Astrophysics Data System (ADS)

Komerska, Anna; Ksionek, Dariusz; Rosiński, Marian

2017-11-01

This article presents results of the energy performance of an external translucent shading component integrated with a phase change material. A proposed technology is able to accumulate considerable amounts of energy in the latent heat by absorbing solar energy. Due to selective optical properties, much of the visible light is still transmitted through the facade. Experimental measurements were carried out in a laboratory set-up - testing thermal chamber, located in the Faculty of Building Services, Hydro and Environmental Engineering at Warsaw University of Technology. The main result of the experimental study was the evaluation of the average solar transmittance in the whole measured spectrum, as well as in the infrared and visible light. Since the shift in optical properties was observed when the material was undergoing a phase transition, the average spectral transmittances were measured for different states of matter of the PCM material. The tested shutter showed abilities to reduce and modulate daylight and solar heat gains in the indoor environment, which could contribute to considerable energy savings.

Development of X-ray CCD camera based X-ray micro-CT system

NASA Astrophysics Data System (ADS)

Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

2017-02-01

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

Programmable hyperspectral image mapper with on-array processing

NASA Technical Reports Server (NTRS)

Cutts, James A. (Inventor)

1995-01-01

A hyperspectral imager includes a focal plane having an array of spaced image recording pixels receiving light from a scene moving relative to the focal plane in a longitudinal direction, the recording pixels being transportable at a controllable rate in the focal plane in the longitudinal direction, an electronic shutter for adjusting an exposure time of the focal plane, whereby recording pixels in an active area of the focal plane are removed therefrom and stored upon expiration of the exposure time, an electronic spectral filter for selecting a spectral band of light received by the focal plane from the scene during each exposure time and an electronic controller connected to the focal plane, to the electronic shutter and to the electronic spectral filter for controlling (1) the controllable rate at which the recording is transported in the longitudinal direction, (2) the exposure time, and (3) the spectral band so as to record a selected portion of the scene through M spectral bands with a respective exposure time t(sub q) for each respective spectral band q.

The benefits of a fast reactor closed fuel cycle in the UK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregg, R.; Hesketh, K.

2013-07-01

The work has shown that starting a fast reactor closed fuel cycle in the UK, requires virtually all of Britain's existing and future PWR spent fuel to be reprocessed, in order to obtain the plutonium needed. The existing UK Pu stockpile is sufficient to initially support only a modest SFR 'closed' fleet assuming spent fuel can be reprocessed shortly after discharge (i.e. after two years cooling). For a substantial fast reactor fleet, most Pu will have to originate from reprocessing future spent PWR fuel. Therefore, the maximum fast reactor fleet size will be limited by the preceding PWR fleet size,more » so scenarios involving fast reactors still require significant quantities of uranium ore indirectly. However, once a fast reactor fuel cycle has been established, the very substantial quantities of uranium tails in the UK would ensure there is sufficient material for several centuries. Both the short and long term impacts on a repository have been considered in this work. Over the short term, the decay heat emanating from the HLW and spent fuel will limit the density of waste within a repository. For scenarios involving fast reactors, the only significant heat bearing actinide content will be present in the final cores, resulting in a 50% overall reduction in decay energy deposited within the repository when compared with an equivalent open fuel cycle. Over the longer term, radiological dose becomes more important. Total radiotoxicity (normalised by electricity generated) is lower for scenarios with Pu recycle after 2000 years. Scenarios involving fast reactors have the lowest radiotoxicity since the quantities of certain actinides (Np, Pu and Am) eventually stabilise. However, total radiotoxicity as a measure of radiological risk does not account for differences in radionuclide mobility once in repository. Radiological dose is dominated by a small number of fission products so is therefore not affected significantly by reactor type or recycling strategy (since the fission product will primarily be a function of nuclear energy generated). However, by reprocessing spent fuel, it is possible to immobilise the fission product in a more suitable waste form that has far more superior in-repository performance. (authors)« less

Bristled shark skin: a microgeometry for boundary layer control?

PubMed

Lang, A W; Motta, P; Hidalgo, P; Westcott, M

2008-12-01

There exists evidence that some fast-swimming shark species may have the ability to bristle their scales during fast swimming. Experimental work using a water tunnel facility has been performed to investigate the flow field over and within a bristled shark skin model submerged within a boundary layer to deduce the possible boundary layer control mechanisms being used by these fast-swimming sharks. Fluorescent dye flow visualization provides evidence of the formation of embedded cavity vortices within the scales. Digital particle image velocimetry (DPIV) data, used to evaluate the cavity vortex formation and boundary layer characteristics close to the surface, indicate increased momentum in the slip layer forming above the scales. This increase in flow velocity close to the shark's skin is indicative of boundary layer control mechanisms leading to separation control and possibly transition delay for the bristled shark skin microgeometry.

Development Of Performance Specifications For Collision Avoidance Systems For Lane Change Merging And Backing, Task 2 - Interim Report: Functional Goals Establishment

DOT National Transportation Integrated Search

1995-02-01

">IN ADDITION TO THE MOST BASIC GOAL OF ELIMINATING THE "BLIND SPOT", SIGNIFICANT CRASH AVOIDANCEOPPORTUNITIES CAN BE REALIZED BY GUARDING AGAINST "FAST CLOSING" VEHICLES DURING LANE CHANGE AND MERGING. THESE "FAST APPROACH" COLLISIONS, THOUGH INFREQ...

Apollo 8 Mission image,Farside of Moon

NASA Image and Video Library

1968-12-21

Apollo 8,Farside of Moon. Image taken on Revolution 4. Camera Tilt Mode: Vertical Stereo. Sun Angle: 13. Original Film Magazine was labeled D. Camera Data: 70mm Hasselblad. Lens: 80mm; F-Stop: F/2.8; Shutter Speed: 1/250 second. Film Type: Kodak SO-3400 Black and White,ASA 40. Flight Date: December 21-27,1968.

Why Do Photo Finish Images Look Weird?

ERIC Educational Resources Information Center

Gregorcic, Bor; Planinsic, Gorazd

2012-01-01

This paper deals with effects that appear on photographs of rotating objects when taken by a photo finish camera, a rolling shutter camera or a computer scanner. These effects are very similar to Roget's palisade illusion. A simple quantitative analysis of the images is also provided. The effects are explored using a computer scanner in a way that…

Portrait of the Rural Community College. New Directions for Community Colleges, Number 90.

ERIC Educational Resources Information Center

Killacky, Jim, Ed.; Valadez, James R., Ed.

1995-01-01

This collection of essays attempts to describe the status and role of the rural community college in higher education, highlighting the special challenges faced by these institutions. The following articles are included: (1) "Opening the Shutter," by James R. Valadez and Jim Killacky; (2) "The Comprehensive Mission of the Rural Community College,"…

New twist on artificial muscles.

PubMed

Haines, Carter S; Li, Na; Spinks, Geoffrey M; Aliev, Ali E; Di, Jiangtao; Baughman, Ray H

2016-10-18

Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy.

Aircraft electric field measurements: Calibration and ambient field retrieval

NASA Technical Reports Server (NTRS)

Koshak, William J.; Bailey, Jeff; Christian, Hugh J.; Mach, Douglas M.

1994-01-01

An aircraft locally distorts the ambient thundercloud electric field. In order to determine the field in the absence of the aircraft, an aircraft calibration is required. In this work a matrix inversion method is introduced for calibrating an aircraft equipped with four or more electric field sensors and a high-voltage corona point that is capable of charging the aircraft. An analytic, closed form solution for the estimate of a (3 x 3) aircraft calibration matrix is derived, and an absolute calibration experiment is used to improve the relative magnitudes of the elements of this matrix. To demonstrate the calibration procedure, we analyze actual calibration date derived from a Lear jet 28/29 that was equipped with five shutter-type field mill sensors (each with sensitivities of better than 1 V/m) located on the top, bottom, port, starboard, and aft positions. As a test of the calibration method, we analyze computer-simulated calibration data (derived from known aircraft and ambient fields) and explicitly determine the errors involved in deriving the variety of calibration matrices. We extend our formalism to arrive at an analytic solution for the ambient field, and again carry all errors explicitly.

New twist on artificial muscles

PubMed Central

Haines, Carter S.; Li, Na; Spinks, Geoffrey M.; Aliev, Ali E.; Di, Jiangtao; Baughman, Ray H.

2016-01-01

Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy. PMID:27671626

35. INTERIOR VIEW OF THE GUARD LOCKS LOCK HOUSE: CLOSED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

35. INTERIOR VIEW OF THE GUARD LOCKS LOCK HOUSE: CLOSED LOCK GATES AND TWO SETS OF MACHINERY TO ASSIST IN OPERATING THEM. VIEW FROM THE FAST END OF THE BUILDING LOOKING WEST 1976 - Pawtucket Canal, Guard Locks, Lowell, Middlesex County, MA

High-voltage, high-current, solid-state closing switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Focia, Ronald Jeffrey

2017-08-22

A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

COS FUV Target Acquisition Monitor

NASA Astrophysics Data System (ADS)

Penton, Steven V.

2017-08-01

Starting in Cycle 25, the COS Target Acquisition (TA) monitor has been divided into two pieces, NUV (15389) and FUV (15386). This program is the FUV portion and is designed specifically for FUV LP4. FUV LP4 uses NUM_POS > 1 PEAKXDs for cross-dispersion TA. All previous LPs used NUM_POS=1 PEAKXDs. The NUM_POS=1 PEAKXDs required the routine monitoring of the grating-dependent WCA-to-PSA offsets. The NUM_POS >1 PEAKXDs do not use these flight software (FSW) patchable constants as they use the LTAPKD FSW macro used in ACQ/PEAKD, but re-purposed for use in the cross-dispersion (XD).This program uses the HST standard star WD1657+343. This target was used previously in the COS TA Monitor programs, 13124 (C20), 13526 (C21), 13972 (C22), 14440 (C23) & 14857 (C24). In these programs, this target was used to co-align the PSA/MIRRORB and BOA/MIRRORA ACQ/IMAGE modes. We re-use this target here as it is safe with PSA/MIRRORA and visible almost year-round.Note that when presented to the mission office, the target 206W3 was listed as the target for this program. This target was a backup target in previous TA monitor programs and was the faintest of the 3 targets in the program. Switching to the next brighter target (WD1657+343) allows all the goals of this program to be accomplished in just 2 orbits. Also, as this target has been used for every generation of this program, the FUV monitoring can be bootstrapped to previous programs, if needed. See the observing description for more details.The LTAIMAGE that started the second orbit of Visit 26 had the TDF down and the shutter closed. This caused the ACQ/IMAGE to miscenter the target by about 1.3". Visit 90 was added as a partial repeat from HOPR 89665. This visit is as close to a repeat of the 2nd orbit of Visi t 25 as possible. Due to time lost doing a full acq instead of a RE-ACQ, the following changes were made:1) Changed Visit number to 902) Schedulability set to 90%3) Before date set to Feb-19-2018, but the earlier the better (this is negotiable)4) Increased Buffer Time for Exposures 90.010 and 90.014 to 976s (2/3 * ETC time)5) Increased Buffer Time for Exposes 90.011 and 90.012 to 2000s (976/0.45 = 2168s)6) Changed exposures times for 90.011 and 90.012 from 182 to 180s.Visit 90 had a GS problem (RGA hold failure) and the entire visit had the shutter closed. HSTAR 14932 was filed along with the approved HOPR 89896. Visit 90 was copied to Visit 91 with the following changes:1) Changed Visit number to 912) Before changed from 19-FEB-2018 to 19-MAR-2018Note that there are 4 exposures with "Y" POS_TARGs in Visit 91 to intentionally offset the target in XD by +/- 1.3"; 2 are G140L and 2 are G160M.We request that previously used, known good, Guide Stars be used, if possible.

77 FR 24970 - National Institute of Mental Health; Notice of Closed Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-26

... Emphasis Panel; Fast Fail--Experimental Medicines Contracts--Mood and Anxiety Disorders. Date: May 22, 2012... Institute of Mental Health Special Emphasis Panel; Fast Fail--Experimental Medicines Contracts--Autism. Date...-- Psychotic Spectrum. Date: May 25, 2012. Time: 1 p.m. to 6 p.m. Agenda: To review and evaluate contract...

Molecular and kinetic determinants of local anaesthetic action on sodium channels.

PubMed

French, R J; Zamponi, G W; Sierralta, I E

1998-11-23

(1) Local anaesthetics (LA) rely for their clinical actions on state-dependent inhibition of voltage-dependent sodium channels. (2) Single, batrachoxin-modified sodium channels in planar lipid bilayers allow direct observation of drug-channel interactions. Two modes of inhibition of single-channel current are observed: fast block of the open channels and prolongation of a long-lived closed state, some of whose properties resemble those of the inactivated state of unmodified channels. (3) Analogues of different parts of the LA molecule separately mimic each blocking mode: amines--fast block, and water-soluble aromatics--closed state prolongation. (4) Interaction between a mu-conotoxin derivative and diethylammonium indicate an intrapore site of fast, open-state block. (5) Site-directed mutagenesis studies suggest that hydrophobic residues in transmembrane segment 6 of repeat domain 4 of sodium channels are critical for both LA binding and stabilization of the inactivated state.

Singular perturbations and time scales in the design of digital flight control systems

NASA Technical Reports Server (NTRS)

Naidu, Desineni S.; Price, Douglas B.

1988-01-01

The results are presented of application of the methodology of Singular Perturbations and Time Scales (SPATS) to the control of digital flight systems. A block diagonalization method is described to decouple a full order, two time (slow and fast) scale, discrete control system into reduced order slow and fast subsystems. Basic properties and numerical aspects of the method are discussed. A composite, closed-loop, suboptimal control system is constructed as the sum of the slow and fast optimal feedback controls. The application of this technique to an aircraft model shows close agreement between the exact solutions and the decoupled (or composite) solutions. The main advantage of the method is the considerable reduction in the overall computational requirements for the evaluation of optimal guidance and control laws. The significance of the results is that it can be used for real time, onboard simulation. A brief survey is also presented of digital flight systems.

A novel guidance law using fast terminal sliding mode control with impact angle constraints.

PubMed

Sun, Lianghua; Wang, Weihong; Yi, Ran; Xiong, Shaofeng

2016-09-01

This paper is concerned with the question of, for a missile interception with impact angle constraints, how to design a guidance law. Firstly, missile interception with impact angle constraints is modeled; secondly, a novel guidance law using fast terminal sliding mode control based on extended state observer is proposed to optimize the trajectory and time of interception; finally, for stationary targets, constant velocity targets and maneuvering targets, the guidance law and the stability of the closed loop system is analyzed and the stability of the closed loop system is analyzed, respectively. Simulation results show that when missile and target are on a collision course, the novel guidance law using fast terminal sliding mode control with extended state observer has more optimized trajectory and effectively reduces the time of interception which has a great significance in modern warfare. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Thematic mapper flight model preshipment review data package. Volume 4: Appendix. Part E: Electronics module data

NASA Technical Reports Server (NTRS)

1982-01-01

Tests to verify the as-designed performance of all circuits within the thematic mapper electronics module unit are described. Specifically, the tests involved the evaluation of the scan line corrector driver, shutter drivers function, cal lamp controller function, post amplifier function, command decoder verification unit, and the temperature and actuator controllers function.

The Shuttering of Educational Studies: Neoliberalism, the Political Spectacle, and Social Injustice at a "World Class" University

ERIC Educational Resources Information Center

Dunn, Alyssa Hadley; Faison, Morgan Zacheya-Jewel

2015-01-01

This article examines the September 2012 closure of the Division of Educational Studies (DES) at Emory University. The authors present this discussion as an example of the ways that the neoliberalization of higher education contributes to the extinction of educational foundations programs. What happened at Emory is symptomatic of the impact that…

Phonation Threshold Pressure Measurement with a Semi-Occluded Vocal Tract

ERIC Educational Resources Information Center

Titze, Ingo R.

2009-01-01

Purpose: The purpose of this article was to determine if a semi-occluded vocal tract could be used to measure phonation threshold pressure. This is in contrast to the shutter technique, where an alternation between a fully occluded tract and an unoccluded tract is used. Method: Five male and 5 female volunteers phonated through a thin straw held…

A Simple Model of the Accommodating Lens of the Human Eye

ERIC Educational Resources Information Center

Oommen, Vinay; Kanthakumar, Praghalathan

2014-01-01

The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, A. A.; Hesjedal, T.; Diamond Light Source, Didcot OX11 0DE

We present a miniaturized molecular beam epitaxy (miniMBE) system with an outer diameter of 206 mm, optimized for flexible and high-throughput operation. The three-chamber system, used here for oxide growth, consists of a sample loading chamber, a storage chamber, and a growth chamber. The growth chamber is equipped with eight identical effusion cell ports with linear shutters, one larger port for either a multi-pocket electron beam evaporator or an oxygen plasma source, an integrated cryoshroud, retractable beam-flux monitor or quartz-crystal microbalance, reflection high energy electron diffraction, substrate manipulator, main shutter, and quadrupole mass spectrometer. The system can be combined withmore » ultrahigh vacuum (UHV) end stations on synchrotron and neutron beamlines, or equivalently with other complex surface analysis systems, including low-temperature scanning probe microscopy systems. Substrate handling is compatible with most UHV surface characterization systems, as the miniMBE can accommodate standard surface science sample holders. We introduce the design of the system, and its specific capabilities and operational parameters, and we demonstrate the epitaxial thin film growth of magnetoelectric Cr{sub 2}O{sub 3} on c-plane sapphire and ferrimagnetic Fe{sub 3}O{sub 4} on MgO (001)« less

Stroboscopic Vision as a Treatment Motion Sickness

NASA Technical Reports Server (NTRS)

Reschke, Millard F.; Somers, J. T.; Ford, G.; Krnavek, J. M.; Hwang, E. y.; Kornilova, L. N.; Leigh, R. J.

2006-01-01

Results obtained from space flight indicate that most space crews will experience some symptoms of motion sickness causing significant impact on the operational objectives that must be accomplished to assure mission success. Based on the initial work of Melvill-Jones, we have evaluated stroboscopic vision as a method of preventing motion sickness. Methods: Nineteen subjects read text while making +/-20deg head movements in the horizontal plane at 0.2 Hz while wearing left-right reversing prisms during exposure to 4 Hz stroboscopic or normal room illumination. Testing was repeated using LCD shutter glasses as the stroboscopic source with an additional 19 subjects. Results: With Strobe, motion sickness was significantly lower than with normal room illumination. Results with the LCD shutter glasses were analogous to those observed with environmental strobe. Conclusions: Stroboscopic illumination appears to be effective where retinal slip is a factor in eliciting motion sickness. Additional research is evaluating the glasses efficacy for, carsickness, sickness in parabolic flight and seasickness. There is evidence from pilot studies showing that the glasses reduce saccade velocity to visually presented targets by approximately half of the normal values. It is interesting to note that adaptation to space flight may also slow saccade velocity.

Performance analysis and enhancement for visible light communication using CMOS sensors

NASA Astrophysics Data System (ADS)

Guan, Weipeng; Wu, Yuxiang; Xie, Canyu; Fang, Liangtao; Liu, Xiaowei; Chen, Yingcong

2018-03-01

Complementary Metal-Oxide-Semiconductor (CMOS) sensors are widely used in mobile-phone and cameras. Hence, it is attractive if these camera can be used as the receivers of visible light communication (VLC). Using the rolling shutter mechanism can increase the data rate of VLC based on CMOS camera, and different techniques have been proposed to improve the demodulation of the rolling shutter mechanism. However, these techniques are too complexity. In this work, we demonstrate and analyze the performance of the VLC link using CMOS camera for different LED luminaires for the first time in our knowledge. Experimental evaluation to compare their bit-error-rate (BER) performances and demodulation are also performed, and it can be summarized that just need to change the LED luminaire with more uniformity light output, the blooming effect would not exist; which not only can reduce the complexity of the demodulation but also enhance the communication quality. In addition, we propose and demonstrate to use contrast limited adaptive histogram equalization to extend the transmission distance and mitigate the influence of the background noise. And the experimental results show that the BER can be decreased by an order of magnitude by using the proposed method.

Luminescence properties after X-ray irradiation for dosimetry

NASA Astrophysics Data System (ADS)

Hong, Duk-Geun; Kim, Myung-Jin

2016-05-01

To investigate the luminescence characteristics after exposure to X-ray radiation, we developed an independent, small X-ray irradiation system comprising a Varian VF-50J mini X-ray generator, a Pb collimator, a delay shutter, and an Al absorber. With this system, the apparent dose rate increased linearly to 0.8 Gy/s against the emission current for a 50 kV anode potential when the shutter was delayed for an initial 4 s and the Al absorber was 300 µm thick. In addition, an approximately 20 mm diameter sample area was irradiated homogeneously with X rays. Based on three-dimensional (3D) thermoluminescence (TL) spectra, the small X-ray irradiator was considered comparable to the conventional 90Sr/90Y beta source even though the TL intensity from beta irradiation was higher than that from X-ray irradiation. The single aliquot regenerative (SAR) growth curve for the small X-ray irradiator was identical to that for the beta source. Therefore, we concluded that the characteristics of the small X-ray irradiator and the conventional 90Sr/90Y beta source were similar and that X ray irradiation had the potential for being suitable for use in luminescence dosimetry.

Picosecond ballistic imaging of diesel injection in high-temperature and high-pressure air

NASA Astrophysics Data System (ADS)

Duran, Sean P.; Porter, Jason M.; Parker, Terence E.

2015-04-01

The first successful demonstration of picosecond ballistic imaging using a 15-ps-pulse-duration laser in diesel sprays at temperature and pressure is reported. This technique uses an optical Kerr effect shutter constructed from a CS2 liquid cell and a 15-ps pulse at 532 nm. The optical shutter can be adjusted to produce effective imaging pulses between 7 and 16 ps. This technique is used to image the near-orifice region (first 3 mm) of diesel sprays from a high-pressure single-hole fuel injector. Ballistic imaging of dodecane and methyl oleate sprays injected into ambient air and diesel injection at preignition engine-like conditions are reported. Dodecane was injected into air heated to 600 °C and pressurized to 20 atm. The resulting images of the near-orifice region at these conditions reveal dramatic shedding of the liquid near the nozzle, an effect that has been predicted, but to our knowledge never before imaged. These shedding structures have an approximate spatial frequency of 10 mm-1 with lengths from 50 to 200 μm. Several parameters are explored including injection pressure, liquid fuel temperature, air temperature and pressure, and fuel type. Resulting trends are summarized with accompanying images.

Effect of Illumination on Ocular Status Modifications Induced by Short-Term 3D TV Viewing

PubMed Central

Chen, Yuanyuan; Xu, Aiqin; Jiang, Jian

2017-01-01

Objectives. This study aimed to compare changes in ocular status after 3D TV viewing under three modes of illumination and thereby identify optimal illumination for 3D TV viewing. Methods. The following measures of ocular status were assessed: the accommodative response, accommodative microfluctuation, accommodative facility, relative accommodation, gradient accommodative convergence/accommodation (AC/A) ratio, phoria, and fusional vergence. The observers watched 3D television for 90 minutes through 3D shutter glasses under three illumination modes: A, complete darkness; B, back illumination (50 lx); and C, front illumination (130 lx). The ocular status of the observers was assessed both before and after the viewing. Results. After 3D TV viewing, the accommodative response and accommodative microfluctuation were significantly changed under illumination Modes A and B. The near positive fusional vergence decreased significantly after the 90-minute 3D viewing session under each illumination mode, and this effect was not significantly different among the three modes. Conclusions. Short-term 3D viewing modified the ocular status of adults. The least amount of such change occurred with front illumination, suggesting that this type of illumination is an appropriate mode for 3D shutter TV viewing. PMID:28348893

Development of the TFTR neutral beam injection system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prichard, Jr., B. A.

1977-01-01

The TFTR Neutral Beam Lines are designed to inject 20 MW of 120 keV neutral deuterium atoms into the plasma. This is accomplished using 12 sources, 65 amperes each, mounted in 4 beam lines. The 120 kV sources and a prototype beam line are being developed. The implementation of these beam lines has required the development of several associated pieces of hardware. 200 kV switch tubes for the power supplies are being developed for modulation and regulation of the accelerating supplies. A 90 cm metallic seal gate valve capable of sealing against atmosphere in either direction is being developed formore » separating the torus and beam line vacuum systems. A 70 x 80 cm fast shutter valve is also being developed to limit tritium migration from the torus into the beam line. Internal to the beam line a calorimeter, ion dump and deflection magnet have been designed to handle three beams, and optical diagnostics utilizing the doppler broadening and doppler shift of light emitted from the accelerated beam are being developed. The control and monitoring of the 12 sources will be done via the TFTR computer control system (CICADA) as will other parts of the machine, and software is being developed to condition and operate the sources automatically. The prototype beam line is scheduled to begin operation in the fall of 1978 and all four production beam lines on TFTR in 1982.« less

Improved Space Object Observation Techniques Using CMOS Detectors

NASA Astrophysics Data System (ADS)

Schildknecht, T.; Hinze, A.; Schlatter, P.; Silha, J.; Peltonen, J.; Santti, T.; Flohrer, T.

2013-08-01

CMOS-sensors, or in general Active Pixel Sensors (APS), are rapidly replacing CCDs in the consumer camera market. Due to significant technological advances during the past years these devices start to compete with CCDs also for demanding scientific imaging applications, in particular in the astronomy community. CMOS detectors offer a series of inherent advantages compared to CCDs, due to the structure of their basic pixel cells, which each contain their own amplifier and readout electronics. The most prominent advantages for space object observations are the extremely fast and flexible readout capabilities, feasibility for electronic shuttering and precise epoch registration, and the potential to perform image processing operations on-chip and in real-time. Presently applied and proposed optical observation strategies for space debris surveys and space surveillance applications had to be analyzed. The major design drivers were identified and potential benefits from using available and future CMOS sensors were assessed. The major challenges and design drivers for ground-based and space-based optical observation strategies have been analyzed. CMOS detector characteristics were critically evaluated and compared with the established CCD technology, especially with respect to the above mentioned observations. Similarly, the desirable on-chip processing functionalities which would further enhance the object detection and image segmentation were identified. Finally, the characteristics of a particular CMOS sensor available at the Zimmerwald observatory were analyzed by performing laboratory test measurements.

Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

NASA Astrophysics Data System (ADS)

Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to μm). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

Stacking with stochastic cooling

NASA Astrophysics Data System (ADS)

Caspers, Fritz; Möhl, Dieter

2004-10-01

Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some considerations to the 'azimuthal' schemes.

Diet-consumer nitrogen isotope fractionation for prolonged fasting arthropods.

PubMed

Mizota, Chitoshi; Yamanaka, Toshiro

2011-12-01

Nitrogen acquisition for cellular metabolism during diapause is a primary concern for herbivorous arthropods. Analyses of naturally occurring stable isotopes of nitrogen help elucidate the mechanism. Relevant articles have cited (58 times up to mid-June 2011) anomalously elevated δ(15)N (per mil deviation of (15)N/(14)N, relative to atmospheric nitrogen=0 ‰) values (diet-consumer nitrogen isotope fractionation; up to 12 ‰) for a prolonged fasting raspberry beetle (Byturus tomentosus Degeer (Coleoptera: Byturidae)), which feeds on red raspberries (Rubus idaeus: δ(15)N= ~ +2 ‰). Biologists have hypothesised that extensive recycling of amino acid nitrogen is responsible for the prolonged fasting. Since this hypothesis was proposed in 1995, scientists have integrated biochemical and molecular knowledge to support the mechanism of prolonged diapausing of animals. To test the validity of the recycling hypothesis, we analysed tissue nitrogen isotope ratios for four Japanese arthropods: the shield bug Parastrachia japonensis Scott (Hemiptera: Cydnidae), the burrower bug Canthophorus niveimarginatus Scott (Hemiptera: Cydnidae), leaf beetle Gastrophysa atrocyanea Motschulsky (Coleoptera: Chrysomelidae) and the Japanese oak silkworm Antheraea yamamai (Lepidoptera: Saturniidae), all of which fast for more than 6 months as part of their life-history strategy. Resulting diet-consumer nitrogen isotope discrimination during fasting ranged from 0 to 7‰, as in many commonly known terrestrial arthropods. We conclude that prolonged fasting of arthropods does not always result in anomalous diet-consumer nitrogen isotope fractionation, since the recycling process is closed or nearly closed with respect to nitrogen isotopes.

Pinhole Cameras: For Science, Art, and Fun!

ERIC Educational Resources Information Center

Button, Clare

2007-01-01

A pinhole camera is a camera without a lens. A tiny hole replaces the lens, and light is allowed to come in for short amount of time by means of a hand-operated shutter. The pinhole allows only a very narrow beam of light to enter, which reduces confusion due to scattered light on the film. This results in an image that is focused, reversed, and…

Apollo 8 Mission image

NASA Image and Video Library

1968-12-21

Apollo 8,Moon, Latitude 15 degrees South,Longitude 170 degrees West. Camera Tilt Mode: High Oblique. Direction: Southeast. Sun Angle 17 degrees. Original Film Magazine was labeled E. Camera Data: 70mm Hasselblad; F-Stop: F-5.6; Shutter Speed: 1/250 second. Film Type: Kodak SO-3400 Black and White,ASA 40. Other Photographic Coverage: Lunar Orbiter 1 (LO I) S-3. Flight Date: December 21-27,1968.

CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

NASA Technical Reports Server (NTRS)

Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

1996-01-01

The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

System for beaming power from earth to a high altitude platform

DOEpatents

Friedman, Herbert W.; Porter, Terry J.

2002-01-01

Power is transmitted to a high altitude platform by an array of diode pumped solid state lasers each operated at a single range of laser wavelengths outside of infrared and without using adaptive optics. Each laser produces a beam with a desired arrival spot size. An aircraft avoidance system uses a radar system for automatic control of the shutters of the lasers.

Enhanced propagation for relativistic laser pulses in inhomogeneous plasmas using hollow channels.

PubMed

Fuchs, J; d'Humières, E; Sentoku, Y; Antici, P; Atzeni, S; Bandulet, H; Depierreux, S; Labaune, C; Schiavi, A

2010-11-26

The influence of long (several millimeters) and hollow channels, bored in inhomogeneous ionized plasma by using a long pulse laser beam, on the propagation of short, ultraintense laser pulses has been studied. Compared to the case without a channel, propagation in channels significantly improves beam transmission and maintains a beam quality close to propagation in vacuum. In addition, the growth of the forward-Raman instability is strongly reduced. These results are beneficial for the direct scheme of the fast ignitor concept of inertial confinement fusion as we demonstrate, in fast-ignition-relevant conditions, that with such channels laser energy can be carried through increasingly dense plasmas close to the fuel core with minimal losses.

Fast and Efficient Discrimination of Traveling Salesperson Problem Stimulus Difficulty

ERIC Educational Resources Information Center

Dry, Matthew J.; Fontaine, Elizabeth L.

2014-01-01

The Traveling Salesperson Problem (TSP) is a computationally difficult combinatorial optimization problem. In spite of its relative difficulty, human solvers are able to generate close-to-optimal solutions in a close-to-linear time frame, and it has been suggested that this is due to the visual system's inherent sensitivity to certain geometric…

Packed rod neutron shield for fast nuclear reactors

DOEpatents

Eck, John E.; Kasberg, Alvin H.

1978-01-01

A fast neutron nuclear reactor including a core and a plurality of vertically oriented neutron shield assemblies surrounding the core. Each assembly includes closely packed cylindrical rods within a polygonal metallic duct. The shield assemblies are less susceptible to thermal stresses and are less massive than solid shield assemblies, and are cooled by liquid coolant flow through interstices among the rods and duct.

Fast growth rate of epitaxial β-Ga2O3 by close coupled showerhead MOCVD

NASA Astrophysics Data System (ADS)

Alema, Fikadu; Hertog, Brian; Osinsky, Andrei; Mukhopadhyay, Partha; Toporkov, Mykyta; Schoenfeld, Winston V.

2017-10-01

We report on the growth of epitaxial β-Ga2O3 thin films on c-plane sapphire substrates using a close coupled showerhead MOCVD reactor. Ga(DPM)3 (DPM = dipivaloylmethanate), triethylgallium (TEGa) and trimethylgallium (TMGa) metal organic (MO) precursors were used as Ga sources and molecular oxygen was used for oxidation. Films grown from each of the Ga sources had high growth rates, with up to 10 μm/hr achieved using a TMGa precursor at a substrate temperature of 900 °C. As confirmed by X-ray diffraction, the films grown from each of the Ga sources were the monoclinic (2 bar 0 1) oriented β-Ga2O3 phase. The optical bandgap of the films was also estimated to be ∼4.9 eV. The fast growth rate of β-Ga2O3 thin films obtained using various Ga-precursors has been achieved due to the close couple showerhead design of the MOCVD reactor as well as the separate injection of oxygen and MO precursors, preventing the premature oxidation of the MO sources. These results suggest a pathway to overcoming the long-standing challenge of realizing fast growth rates for Ga2O3 using the MOCVD method.

Water-only fasting and an exclusively plant foods diet in the management of stage IIIa, low-grade follicular lymphoma.

PubMed

Goldhamer, Alan C; Klaper, Michael; Foorohar, Afsoon; Myers, Toshia R

2015-12-10

Follicular lymphoma (FL), the second most common non-Hodgkin's lymphoma (NHL), is well characterised by a classic histological appearance and an indolent course. Current treatment protocols for FL range from close observation to immunotherapy, chemotherapy and/or radiotherapies. We report the case of a 42-year-old woman diagnosed by excisional biopsy with stage IIIa, grade 1 FL. In addition to close observation, the patient underwent a medically supervised, 21-day water-only fast after which enlarged lymph nodes were substantially reduced in size. The patient then consumed a diet of minimally processed plant foods free of added sugar, oil and salt (SOS), and has remained on the diet since leaving the residential facility. At 6 and 9-month follow-up visits, the patient's lymph nodes were non-palpable and she remained asymptomatic. This case establishes a basis for further studies evaluating water-only fasting and a plant foods, SOS-free diet as a treatment protocol for FL. 2015 BMJ Publishing Group Ltd.

Water-only fasting and an exclusively plant foods diet in the management of stage IIIa, low-grade follicular lymphoma

PubMed Central

Klaper, Michael; Foorohar, Afsoon; Myers, Toshia R

2015-01-01

Follicular lymphoma (FL), the second most common non-Hodgkin's lymphoma (NHL), is well characterised by a classic histological appearance and an indolent course. Current treatment protocols for FL range from close observation to immunotherapy, chemotherapy and/or radiotherapies. We report the case of a 42-year-old woman diagnosed by excisional biopsy with stage IIIa, grade 1 FL. In addition to close observation, the patient underwent a medically supervised, 21-day water-only fast after which enlarged lymph nodes were substantially reduced in size. The patient then consumed a diet of minimally processed plant foods free of added sugar, oil and salt (SOS), and has remained on the diet since leaving the residential facility. At 6 and 9-month follow-up visits, the patient's lymph nodes were non-palpable and she remained asymptomatic. This case establishes a basis for further studies evaluating water-only fasting and a plant foods, SOS-free diet as a treatment protocol for FL. PMID:26655228

The Edge of Stability: Response Times and Delta Oscillations in Balanced Networks

PubMed Central

Gillary, Grant; Niebur, Ernst

2016-01-01

The standard architecture of neocortex is a network with excitation and inhibition in closely maintained balance. These networks respond fast and with high precision to their inputs and they allow selective amplification of patterned signals. The stability of such networks is known to depend on balancing the strengths of positive and negative feedback. We here show that a second condition is required for stability which depends on the relative strengths and time courses of fast (AMPA) and slow (NMDA) currents in the excitatory projections. This condition also determines the response time of the network. We show that networks which respond quickly to an input are necessarily close to an oscillatory instability which resonates in the delta range. This instability explains the existence of neocortical delta oscillations and the emergence of absence epilepsy. Although cortical delta oscillations are a network-level phenomenon, we show that in non-pathological networks, individual neurons receive sufficient information to keep the network in the fast-response regime without sliding into the instability. PMID:27689361

Fast and precise technique for magnet lattice correction via sine-wave excitation of fast correctors

DOE PAGES

Yang, X.; Smaluk, V.; Yu, L. H.; ...

2017-05-02

A novel technique has been developed to improve the precision and shorten the measurement time of the LOCO (linear optics from closed orbits) method. This technique, named AC LOCO, is based on sine-wave (ac) beam excitation via fast correctors. Such fast correctors are typically installed at synchrotron light sources for the fast orbit feedback. The beam oscillations are measured by beam position monitors. The narrow band used for the beam excitation and measurement not only allows us to suppress effectively the beam position noise but also opens the opportunity for simultaneously exciting multiple correctors at different frequencies (multifrequency mode). Wemore » demonstrated at NSLS-II that AC LOCO provides better lattice corrections and works much faster than the traditional LOCO method.« less

Telescope Fabra ROA Montsec: A New Robotic Wide Field Baker-Nunn Facility

NASA Astrophysics Data System (ADS)

Fors, Octavi; Núñez, Jorge; Muiños, José Luis; Montojo, Francisco Javier; Baena-Gallé, Roberto; Boloix, Jaime; Morcillo, Ricardo; Merino, María Teresa; Downey, Elwood C.; Mazur, Michael J.

2013-05-01

A Baker-Nunn Camera (BNC), originally installed at the Real Instituto y Observatorio de la Armada (ROA) in 1958, was refurbished and robotized. The new facility, called Telescope Fabra ROA Montsec (TFRM), was installed at the Observatori Astronòmic del Montsec (OAdM). The process of refurbishment is described in detail. Most of the steps of the refurbishment project were accomplished by purchasing commercial components, which involve little posterior engineering assembling work. The TFRM is a 0.5 m aperture f/0.96 optically modified BNC, which offers a unique combination of instrumental specifications: fully robotic and remote operation, wide field of view (4°.4 × 4°.4), moderate limiting magnitude (V ˜ 19.5 mag), ability of tracking at arbitrary right ascension (α) and declination (δ) rates, as well as opening and closing CCD shutter at will during an exposure. Nearly all kinds of image survey programs can benefit from those specifications. Apart from other less time-consuming programs, since the beginning of science TFRM operations we have been conducting two specific and distinct surveys: super-Earths transiting around M-type dwarfs stars, and geostationary debris in the context of Space Situational Awareness/Space Surveillance and Tracking (SSA/SST) programs. Preliminary results for both cases will be shown.

High-speed imaging using 3CCD camera and multi-color LED flashes

NASA Astrophysics Data System (ADS)

Hijazi, Ala; Friedl, Alexander; Cierpka, Christian; Kähler, Christian; Madhavan, Vis

2017-11-01

This paper demonstrates the possibility of capturing full-resolution, high-speed image sequences using a regular 3CCD color camera in conjunction with high-power light emitting diodes of three different colors. This is achieved using a novel approach, referred to as spectral-shuttering, where a high-speed image sequence is captured using short duration light pulses of different colors that are sent consecutively in very close succession. The work presented in this paper demonstrates the feasibility of configuring a high-speed camera system using low cost and readily available off-the-shelf components. This camera can be used for recording six-frame sequences at frame rates up to 20 kHz or three-frame sequences at even higher frame rates. Both color crosstalk and spatial matching between the different channels of the camera are found to be within acceptable limits. A small amount of magnification difference between the different channels is found and a simple calibration procedure for correcting the images is introduced. The images captured using the approach described here are of good quality to be used for obtaining full-field quantitative information using techniques such as digital image correlation and particle image velocimetry. A sequence of six high-speed images of a bubble splash recorded at 400 Hz is presented as a demonstration.

Enhanced way of securing automated teller machine to track the misusers using secure monitor tracking analysis

NASA Astrophysics Data System (ADS)

Sadhasivam, Jayakumar; Alamelu, M.; Radhika, R.; Ramya, S.; Dharani, K.; Jayavel, Senthil

2017-11-01

Now a days the people's attraction towards Automated Teller Machine(ATM) has been increasing even in rural areas. As of now the security provided by all the bank is ATM pin number. Hackers know the way to easily identify the pin number and withdraw money if they haven stolen the ATM card. Also, the Automated Teller Machine is broken and the money is stolen. To overcome these disadvantages, we propose an approach “Automated Secure Tracking System” to secure and tracking the changes in ATM. In this approach, while creating the bank account, the bank should scan the iris known (a part or movement of our eye) and fingerprint of the customer. The scanning can be done with the position of the eye movements and fingerprints identified with the shortest measurements. When the card is swiped then ATM should request the pin, scan the iris and recognize the fingerprint and then allow the customer to withdraw money. If somebody tries to break the ATM an alert message is given to the nearby police station and the ATM shutter is automatically closed. This helps in avoiding the hackers who withdraw money by stealing the ATM card and also helps the government in identifying the criminals easily.

Improving precision of Pi of the Sky photometric measurements

NASA Astrophysics Data System (ADS)

Siudek, M.; Małek, K.; Mankiewicz, L.; Opiela, R.; Sokołowski, M.; Źarnecki, A. F.

Pi of the Sky is a system of robotic telescopes designed for observations of short timescale astrophysical phenomena, like prompt optical GRB emission. The apparatus is designed to monitor a large fraction of the sky with 12^{m} - 13^{m} range and time resolution of the order of 1, 10 seconds. All measurements taken by the Pi of the Sky detector located in Las Campanas Observatory (LCO) in Chile are available on the Pi of the Sky website through a dedicated interface which also allows to download the selected data. Pi of the Sky database from period 2006 - 2009 contains more than 2 billions measurements of almost 17 millions of objects. In order to facilitate analysis of variable stars we have developed a system of dedicated filters to remove bad measurements or frames. They are needed to remove measurements affected by detector imperfections (hot pixels, measurement close to CCD edge, background due to opened shutter) or observation conditions (planet or planetoid passage, moon halo). With approximate color calibration algorithm taking into account appropriate corrections based on the spectral type of reference stars the photometry algorithm can be improved further. This process is illustrated by the analysis of the BG Ind system where we have been able to reduce the total systematic uncertainty to about 0.05 magnitudes.

Broadband light-emitting diode

DOEpatents

Fritz, Ian J.; Klem, John F.; Hafich, Michael J.

1998-01-01

A broadband light-emitting diode. The broadband light-emitting diode (LED) comprises a plurality of III-V compound semiconductor layers grown on a semiconductor substrate, with the semiconductor layers including a pair of cladding layers sandwiched about a strained-quantum-well active region having a plurality of different energy bandgaps for generating light in a wavelength range of about 1.3-2 .mu.m. In one embodiment of the present invention, the active region may comprise a first-grown quantum-well layer and a last-grown quantum-well layer that are oppositely strained; whereas in another embodiment of the invention, the active region is formed from a short-period superlattice structure (i.e. a pseudo alloy) comprising alternating thin layers of InGaAs and InGaAlAs. The use a short-period superlattice structure for the active region allows different layers within the active region to be simply and accurately grown by repetitively opening and closing one or more shutters in an MBE growth apparatus to repetitively switch between different growth states therein. The broadband LED may be formed as either a surface-emitting LED or as an edge-emitting LED for use in applications such as chemical sensing, fiber optic gyroscopes, wavelength-division-multiplexed (WDM) fiber-optic data links, and WDM fiber-optic sensor networks for automobiles and aircraft.

Broadband light-emitting diode

DOEpatents

Fritz, I.J.; Klem, J.F.; Hafich, M.J.

1998-07-14

A broadband light-emitting diode is disclosed. The broadband light-emitting diode (LED) comprises a plurality of III-V compound semiconductor layers grown on a semiconductor substrate, with the semiconductor layers including a pair of cladding layers sandwiched about a strained-quantum-well active region having a plurality of different energy bandgaps for generating light in a wavelength range of about 1.3--2 {micro}m. In one embodiment of the present invention, the active region may comprise a first-grown quantum-well layer and a last-grown quantum-well layer that are oppositely strained; whereas in another embodiment of the invention, the active region is formed from a short-period superlattice structure (i.e. a pseudo alloy) comprising alternating thin layers of InGaAs and InGaAlAs. The use a short-period superlattice structure for the active region allows different layers within the active region to be simply and accurately grown by repetitively opening and closing one or more shutters in an MBE growth apparatus to repetitively switch between different growth states therein. The broadband LED may be formed as either a surface-emitting LED or as an edge-emitting LED for use in applications such as chemical sensing, fiber optic gyroscopes, wavelength-divisionmultiplexed (WDM) fiber-optic data links, and WDM fiber-optic sensor networks for automobiles and aircraft. 10 figs.

Analysis of EEG signals regularity in adults during video game play in 2D and 3D.

PubMed

Khairuddin, Hamizah R; Malik, Aamir S; Mumtaz, Wajid; Kamel, Nidal; Xia, Likun

2013-01-01

Video games have long been part of the entertainment industry. Nonetheless, it is not well known how video games can affect us with the advancement of 3D technology. The purpose of this study is to investigate the EEG signals regularity when playing video games in 2D and 3D modes. A total of 29 healthy subjects (24 male, 5 female) with mean age of 21.79 (1.63) years participated. Subjects were asked to play a car racing video game in three different modes (2D, 3D passive and 3D active). In 3D passive mode, subjects needed to wear a passive polarized glasses (cinema type) while for 3D active, an active shutter glasses was used. Scalp EEG data was recorded during game play using 19-channel EEG machine and linked ear was used as reference. After data were pre-processed, the signal irregularity for all conditions was computed. Two parameters were used to measure signal complexity for time series data: i) Hjorth-Complexity and ii) Composite Permutation Entropy Index (CPEI). Based on these two parameters, our results showed that the complexity level increased from eyes closed to eyes open condition; and further increased in the case of 3D as compared to 2D game play.

Magnetically driven cold valve for 4He

NASA Astrophysics Data System (ADS)

Bueno, J.; Blaauwgeers, R.; Partapsing, R.; Taminiau, I.; Jochemsen, R.

2006-08-01

We have designed a low temperature valve for liquid helium, which uses a magnetic field gradient and a permanent magnet to close. For closing, it presses a small ruby ball onto a Torlon seat. We present a small valve that is easy to build and easily controlled via two wires. It has a fast response, reliable, and has the advantage that there is no dead volume change on closing and no additional helium line is required to operate.

Registration of Large Motion Blurred Images

DTIC Science & Technology

2016-05-09

in handling the dynamics of the capturing system, for example, a drone. CMOS sensors , used in recent times, when employed in these cameras produce...handling the dynamics of the capturing system, for example, a drone. CMOS sensors , used in recent times, when employed in these cameras produce two types...blur in the captured image when there is camera motion during exposure. However, contemporary CMOS sensors employ an electronic rolling shutter (RS

Utilizing Microelectromechanical Systems (MEMS) Micro-Shutter Designs for Adaptive Coded Aperture Imaging (ACAI) Technologies

DTIC Science & Technology

2009-03-01

52 Figure 4-1: Applied voltage versus deflection curve for Poly1/Poly2 stacked 300-μm single hot-arm actuator (shown on right...58 Figure 4-2: Applied voltage versus deflection curve for Poly1/Poly2 stacked 300-μm double hot-arm actuator (shown on...61 Figure 4-5: Deflection vs. power curves for an individual wedge from

Development of an Airborne High Resolution TV System (AHRTS)

DTIC Science & Technology

1975-11-01

GOVT ACCESSION NO READ INSTRUCTIONS BEFORE COMPLETING FORM JP RECIPIENT’S CATALOG NUMBER DEVELOPMENT OF AN ^IRBORNE HIGH JESOLUTION TV SYSTEM...c. Sytem Elements The essential Airborne Subsystem elements of camera, video tape recorder, transmitter and antennas are required to have...The camera operated over the 3000:1 light change as required. A solar shutter was Incorporated to protect the vidicon from damage from direct view

Automatic Exposure Iris Control (AEIC) for data acquisition camera

NASA Technical Reports Server (NTRS)

Mcatee, G. E., Jr.; Stoap, L. J.; Solheim, C. D.; Sharpsteen, J. T.

1975-01-01

A lens design capable of operating over a total range of f/1.4 to f/11.0 with through the lens light sensing is presented along with a system which compensates for ASA film speeds as well as shutter openings. The space shuttle camera system package is designed so that it can be assembled on the existing 16 mm DAC with a minimum of alteration to the camera.

Laser Measurement Of Convective-Heat-Transfer Coefficient

NASA Technical Reports Server (NTRS)

Porro, A. Robert; Hingst, Warren R.; Chriss, Randall M.; Seablom, Kirk D.; Keith, Theo G., Jr.

1994-01-01

Coefficient of convective transfer of heat at spot on surface of wind-tunnel model computed from measurements acquired by developmental laser-induced-heat-flux technique. Enables non-intrusive measurements of convective-heat-transfer coefficients at many points across surfaces of models in complicated, three-dimensional, high-speed flows. Measurement spot scanned across surface of model. Apparatus includes argon-ion laser, attenuator/beam splitter electronic shutter infrared camera, and subsystem.

Digital Semaphore: Technical Feasibility of QR Code Optical Signaling for Fleet Communications

DTIC Science & Technology

2013-06-01

Standards (http://www.iso.org) JIS Japanese Industrial Standard JPEG Joint Photographic Experts Group (digital image format; http://www.jpeg.org) LED...Denso Wave corporation in the 1990s for the Japanese automotive manufacturing industry. See Appendix A for full details. Reed-Solomon Error...eliminates camera blur induced by the shutter, providing clear images at extremely high frame rates. Thusly, digital cinema cameras are more suitable

Afghanistan, Counterinsurgency, and the Indirect Approach

DTIC Science & Technology

2010-04-01

shuttered cinemas , barred people from watching the soccer World Cup, and held public amputations or stonings of violators of their stark religious... Japanese warplanes struck the U.S. Navy at Pearl Harbor, Japan invaded the islands. The Impe- rial Japanese Army defeated the tiny American garrisons at...U.S. forces freed the Philippines from Japanese rule. Nearly 2 years later, the island nation attained its full sovereignty on 4 July 1946. The

The BepiColombo Serena/ELENA instrument: performances and testing

NASA Astrophysics Data System (ADS)

Orsini, Stefano; De Angelis, Elisabetta; Selci, Stefano; Di Lellis, Andrea; Leoni, Roberto; Rispoli, Rosanna; Colasanti, Luca; Vertolli, Nello; Mura, Alessandro; Milillo, Anna; D'Alessandro, Marco; Mattioli, Francesco; Maschietti, Daniele; Brienza, Daniele; Scheer, Juergen; Wurz, Peter

2013-04-01

The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV, within 1-D (4.5°x76°). ELENA is a Time of Flight instrument, based on the novel concept of ultra-sonic oscillating shutter as Start section and MCP detector with 32 discrete anodes as a direct Stop section. ELENA will monitor the emission of neutral atoms from the whole surface of Mercury allowing to investigate the interaction between the environment and the planet, the global particle loss-rate and the remote sensing of the surface properties. In particular, surface release processes are investigated by identifying particles release from the surface via solar wind-induced ion sputtering (<1eV - >100 eV) as well as Hydrogen back-scattered at hundreds eV. The results of ELENA performance test, will be presented: the innovative Shutter system (Start section) operating at requested frequencies (around 43kHz), the ion rejection capability of double deflection system, the Stop detector, the electronic boards, the validation test.

30-W Yb3+-pulsed fiber laser with wavelength tuning

NASA Astrophysics Data System (ADS)

Davydov, B. L.; Krylov, A. A.

2007-12-01

We have investigated various pulsed operation regimes of a diode-pumped Yb3+-doped fiber laser with both an acoustooptic filter and a shutter inside the resonator. To imbed the polarization-sensitive acoustooptic-tunable spectral filter into the polarization-nonmaintaining resonator, based on an “isotropic” single-mode fiber without “polarization’ losses, we have used a CaCO3 single-crystal nondispersive thermostable polarization splitter. Stable smooth bell-shaped laser pulses were obtained in the Q-switch generation regime across the entire wavelength tuning band. Their duration depended on the resonator travel time and their repetition rate was determined exclusively by the outer high-frequency generator controlling the acoustooptic shutter. A pulsed laser radiation tuning bandwidth of more than 20-nm at a repetition rate band of 10-100 kHz was observed in the amplification band of the Yb3+-doped fiber. A stable average power of 30 W of the pulsed 70-ns 100-kHz laser radiation in a near Gaussian beam was reached by means of the two-stage amplifier based on Yb3+-doped fibers with an enlarged mode field diameter (14 μm). The amplifier was pumped by λ = 975 nm CW multimode laser diodes with a maximum average power of 42 W.

Arrays of quasi-hexagonally ordered silica nanopillars with independently controlled areal density, diameter and height gradients

NASA Astrophysics Data System (ADS)

Özdemir, Burcin; Huang, Wenting; Plettl, Alfred; Ziemann, Paul

2015-03-01

A consecutive fabrication approach of independently tailored gradients of the topographical parameters distance, diameter and height in arrays of well-ordered nanopillars on smooth SiO2-Si-wafers is presented. For this purpose, previously reported preparation techniques are further developed and combined. First, self-assembly of Au-salt loaded micelles by dip-coating with computer-controlled pulling-out velocities and subsequent hydrogen plasma treatment produce quasi-hexagonally ordered, 2-dimensional arrays of Au nanoparticles (NPs) with unidirectional variations of the interparticle distances along the pulling direction between 50-120 nm. Second, the distance (or areal density) gradient profile received in this way is superimposed with a diameter-controlled gradient profile of the NPs applying a selective photochemical growth technique. For demonstration, a 1D shutter is used for locally defined UV exposure times to prepare Au NP size gradients varying between 12 and 30 nm. Third, these double-gradient NP arrangements serve as etching masks in a following reactive ion etching step delivering arrays of nanopillars. For height gradient generation, the etching time is locally controlled by applying a shutter made from Si wafer piece. Due to the high flexibility of the etching process, the preparation route works on various materials such as cover slips, silicon, silicon oxide, silicon nitride and silicon carbide.

Creating Ruddlesden-Popper phases by hybrid molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Haislmaier, Ryan C.; Stone, Greg; Alem, Nasim; Engel-Herbert, Roman

2016-07-01

The synthesis of a 50 unit cell thick n = 4 Srn+1TinO3n+1 (Sr5Ti4O13) Ruddlesden-Popper (RP) phase film is demonstrated by sequentially depositing SrO and TiO2 layers in an alternating fashion using hybrid molecular beam epitaxy (MBE), where Ti was supplied using titanium tetraisopropoxide (TTIP). A detailed calibration procedure is outlined for determining the shuttering times to deposit SrO and TiO2 layers with precise monolayer doses using in-situ reflection high energy electron diffraction (RHEED) as feedback. Using optimized Sr and TTIP shuttering times, a fully automated growth of the n = 4 RP phase was carried out over a period of >4.5 h. Very stable RHEED intensity oscillations were observed over the entire growth period. The structural characterization by X-ray diffraction and high resolution transmission electron microscopy revealed that a constant periodicity of four SrTiO3 perovskite unit cell blocks separating the double SrO rocksalt layer was maintained throughout the entire film thickness with a very little amount of planar faults oriented perpendicular to the growth front direction. These results illustrate that hybrid MBE is capable of layer-by-layer growth with atomic level precision and excellent flux stability.

Time multiplexing for increased FOV and resolution in virtual reality

NASA Astrophysics Data System (ADS)

Miñano, Juan C.; Benitez, Pablo; Grabovičkić, Dejan; Zamora, Pablo; Buljan, Marina; Narasimhan, Bharathwaj

2017-06-01

We introduce a time multiplexing strategy to increase the total pixel count of the virtual image seen in a VR headset. This translates into an improvement of the pixel density or the Field of View FOV (or both) A given virtual image is displayed by generating a succession of partial real images, each representing part of the virtual image and together representing the virtual image. Each partial real image uses the full set of physical pixels available in the display. The partial real images are successively formed and combine spatially and temporally to form a virtual image viewable from the eye position. Partial real images are imaged through different optical channels depending of its time slot. Shutters or other schemes are used to avoid that a partial real image be imaged through the wrong optical channels or at the wrong time slot. This time multiplexing strategy needs real images be shown at high frame rates (>120fps). Available display and shutters technologies are discussed. Several optical designs for achieving this time multiplexing scheme in a compact format are shown. This time multiplexing scheme allows increasing the resolution/FOV of the virtual image not only by increasing the physical pixel density but also by decreasing the pixels switching time, a feature that may be simpler to achieve in certain circumstances.

Objective Evaluation of Visual Fatigue Using Binocular Fusion Maintenance.

PubMed

Hirota, Masakazu; Morimoto, Takeshi; Kanda, Hiroyuki; Endo, Takao; Miyoshi, Tomomitsu; Miyagawa, Suguru; Hirohara, Yoko; Yamaguchi, Tatsuo; Saika, Makoto; Fujikado, Takashi

2018-03-01

In this study, we investigated whether an individual's visual fatigue can be evaluated objectively and quantitatively from their ability to maintain binocular fusion. Binocular fusion maintenance (BFM) was measured using a custom-made binocular open-view Shack-Hartmann wavefront aberrometer equipped with liquid crystal shutters, wherein eye movements and wavefront aberrations were measured simultaneously. Transmittance in the liquid crystal shutter in front of the subject's nondominant eye was reduced linearly, and BFM was determined from the transmittance at the point when binocular fusion was broken and vergence eye movement was induced. In total, 40 healthy subjects underwent the BFM test and completed a questionnaire regarding subjective symptoms before and after a visual task lasting 30 minutes. BFM was significantly reduced after the visual task ( P < 0.001) and was negatively correlated with the total subjective eye symptom score (adjusted R 2 = 0.752, P < 0.001). Furthermore, the diagnostic accuracy for visual fatigue was significantly higher in BFM than in the conventional test results (aggregated fusional vergence range, near point of convergence, and the high-frequency component of accommodative microfluctuations; P = 0.007). These results suggest that BFM can be used as an indicator for evaluating visual fatigue. BFM can be used to evaluate the visual fatigue caused by the new visual devices, such as head-mount display, objectively.

Valve for gas centrifuges

DOEpatents

Hahs, Charles A.; Burbage, Charles H.

1984-01-01

The invention is a pneumatically operated valve assembly for simultaneously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two of the lines so closed. The valve assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

Valve for gas centrifuges

DOEpatents

Hahs, C.A.; Rurbage, C.H.

1982-03-17

The invention is pneumatically operated valve assembly for simulatenously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two on the lines so closed. The value assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

The basic features of a closed fuel cycle without fast reactors

NASA Astrophysics Data System (ADS)

Bobrov, E. A.; Alekseev, P. N.; Teplov, P. S.

2017-01-01

In this paper the basic features of a closed fuel cycle with thermal reactors are considered. The three variants of multiple Pu and U recycling in VVER reactors was investigated. The comparison of MOX and REMIX fuel approaches for closed fuel cycle with thermal reactors is presented. All variants make possible to recycle several times the total amount of Pu and U obtained from spent fuel. The reported study was funded by RFBR according to the research project № 16-38-00021

The design of a microscopic system for typical fluorescent in-situ hybridization applications

NASA Astrophysics Data System (ADS)

Yi, Dingrong; Xie, Shaochuan

2013-12-01

Fluorescence in situ hybridization (FISH) is a modern molecular biology technique used for the detection of genetic abnormalities in terms of the number and structure of chromosomes and genes. The FISH technique is typically employed for prenatal diagnosis of congenital dementia in the Obstetrics and Genecology department. It is also routinely used to pick up qualifying breast cancer patients that are known to be highly curable by the prescription of Her2 targeted therapy. During the microscopic observation phase, the technician needs to count typically green probe dots and red probe dots contained in a single nucleus and calculate their ratio. This procedure need to be done to over hundreds of nuclei. Successful implementation of FISH tests critically depends on a suitable fluorescent microscope which is primarily imported from overseas due to the complexity of such a system beyond the maturity of the domestic optoelectrical industry. In this paper, the typical requirements of a fluorescent microscope that is suitable for FISH applications are first reviewed. The focus of this paper is on the system design and computational methods of an automatic florescent microscopy with high magnification APO objectives, a fast spinning automatic filter wheel, an automatic shutter, a cooled CCD camera used as a photo-detector, and a software platform for image acquisition, registration, pseudo-color generation, multi-channel fusing and multi-focus fusion. Preliminary results from FISH experiments indicate that this system satisfies routine FISH microscopic observation tasks.

X-band EPR setup with THz light excitation of Novosibirsk Free Electron Laser: Goals, means, useful extras

NASA Astrophysics Data System (ADS)

Veber, Sergey L.; Tumanov, Sergey V.; Fursova, Elena Yu.; Shevchenko, Oleg A.; Getmanov, Yaroslav V.; Scheglov, Mikhail A.; Kubarev, Vitaly V.; Shevchenko, Daria A.; Gorbachev, Iaroslav I.; Salikova, Tatiana V.; Kulipanov, Gennady N.; Ovcharenko, Victor I.; Fedin, Matvey V.

2018-03-01

Electron Paramagnetic Resonance (EPR) station at the Novosibirsk Free Electron Laser (NovoFEL) user facility is described. It is based on X-band (∼9 GHz) EPR spectrometer and operates in both Continuous Wave (CW) and Time-Resolved (TR) modes, each allowing detection of either direct or indirect influence of high-power NovoFEL light (THz and mid-IR) on the spin system under study. The optics components including two parabolic mirrors, shutters, optical chopper and multimodal waveguide allow the light of NovoFEL to be directly fed into the EPR resonator. Characteristics of the NovoFEL radiation, the transmission and polarization-retaining properties of the waveguide used in EPR experiments are presented. The types of proposed experiments accessible using this setup are sketched. In most practical cases the high-power radiation applied to the sample induces its rapid temperature increase (T-jump), which is best visible in TR mode. Although such influence is a by-product of THz radiation, this thermal effect is controllable and can deliberately be used to induce and measure transient signals of arbitrary samples. The advantage of tunable THz radiation is the absence of photo-induced processes in the sample and its high penetration ability, allowing fast heating of a large portion of virtually any sample and inducing intense transients. Such T-jump TR EPR spectroscopy with THz pulses has been previewed for the two test samples, being a useful supplement for the main goals of the created setup.

Factors influencing the measurement of closing volume.

PubMed

Make, B; Lapp, N L

1975-06-01

The various factors influencing closing volume were studied by performing the single-breath N2 test on 9 healthy nonsmokers. Time of day, day of the week, and preceding volume history had no effect on either closing volume or alveolar plateau. Slow inspiratory flow resulted in larger ratio of closing volume to vital capacity, ratio of closing capacity to total lung capacity, and change in N2 concentration than fast inspiratory flow. Voluntary regulation of the expiratory flow resulted in smaller ratios of closing volume to vital capacity and closing capacity to total lung capacity than when flow was regulated by a resistance. Prolonged breath holding of the inspired O2 led to larger ratio of closing volume to vital capacity and ratio of closing capacity to total lung capacity. To obtain uniform, comparable closing volumes, it is suggested that the subject inspire slowly, control expiratory flow (preferably voluntarily), and not pause between inspiration and expiration.

Obesogenic neighbourhoods: the impact of neighbourhood restaurants and convenience stores on adolescents' food consumption behaviours.

PubMed

He, Meizi; Tucker, Patricia; Irwin, Jennifer D; Gilliland, Jason; Larsen, Kristian; Hess, Paul

2012-12-01

To examine the relationship between the neighbourhood food environment and dietary intake among adolescents. Cross-sectional design using: (i) a geographic information system to assess characteristics of the neighbourhood food environment and neighbourhood socio-economic status; (ii) the modified Healthy Eating Index (HEI) to assess participants' overall diet quality; and (iii) generalized linear models to examine associations between HEI and home and school food environmental correlates. Mid-sized Canadian city in Ontario, Canada. Participants Grade 7 and 8 students (n 810) at twenty-one elementary schools. Students living in neighbourhoods with a lower diversity of land-use types, compared with their higher diversity counterparts, had higher HEI scores (P < 0.05). Students with more than 1 km between their home and the nearest convenience store had higher HEI scores than those living within 1 km (P < 0.01). Students attending schools with a distance further than 1 km from the nearest convenience store (P < 0.01) and fast-food outlet (P < 0.05) had higher HEI scores than those within 1 km. Those attending schools with three or more fast-food outlets within 1 km had lower HEI scores than those attending schools with no fast-food outlet in the school surroundings (P < 0.05). Close proximity to convenience stores in adolescents' home environments is associated with low HEI scores. Within adolescents' school environments, close proximity to convenience and fast-food outlets and a high density of fast-food outlets are associated with low HEI scores.

A FAST PROPAGATING EXTREME-ULTRAVIOLET WAVE ASSOCIATED WITH A MINI-FILAMENT ERUPTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng Ruisheng; Jiang Yunchun; Yang Jiayan

The fast extreme-ultraviolet (EUV) waves (>1000 km s{sup -1}) in the solar corona were very rare in the past. Taking advantage of the high temporal and spatial resolution of the Solar Dynamics Observatory observations, we present a fast EUV wave associated with a mini-filament eruption, a C1.0 flare, and a coronal mass ejection (CME) on 2011 September 30. The event took place at the periphery between two active regions (ARs). The mini-filament rapidly erupted as a blowout jet associated with a flare and a CME. The CME front was likely developed from the large-scale overlying loops. The wave onset wasmore » nearly simultaneous with the start of the jet and the flare. The wave departed far from the flare center and showed a close location relative to the rapid jet. The wave had an initial speed of about 1100 km s{sup -1} and a slight deceleration in the last phase, and the velocity decreased to about 500 km s{sup -1}. The wave propagated in a narrow angle extent, likely to avoid the ARs on both sides. All the results provide evidence that the fast EUV wave was a fast-mode MHD wave. The wave resisted being driven by the CME, because it opened up the large-scale loops and its front likely formed later than the wave. The wave was most likely triggered by the jet, due to their close timing and location relations.« less

An Experimental Determination of Subatmospheric Burning Rates and Critical Diameters for AP/HTPB Propellant

DTIC Science & Technology

1988-12-01

round uses an AP/HTPB propellant in the projectile base to reduce base drag during flight . Subatmospheric burning rates, simulating operation at...the partial vacuum created at the projectile base in flight . The combustion gases escape the combustion chamber through an unchoked port in the...determination. Combustion of the sample was video recorded by a system with both synchronized electronic strobe and shutter. The camera captures 60 fields

Control of Hazards to Health From Laser Radiation

DTIC Science & Technology

2006-01-01

compared to the calculated AEL. (2) Optically aided viewing. Viewing a laser beam with optical aids (other than ordinary eyeglasses or contact lenses ...resonant optical cavity. TB MED 524 8 b. Lenses , mirrors, cooling systems, shutters, and other accessories may be added to the system to obtain...procedures for laser optical systems (for example, mirrors, prisms, and lenses ) that employ Class 2 and Class 3a lasers, it is always good laser safety

Application of the Digital Image Technology in the Visual Monitoring and Prediction of Shuttering Construction Safety

NASA Astrophysics Data System (ADS)

Ummin, Okumura; Tian, Han; Zhu, Haiyu; Liu, Fuqiang

2018-03-01

Construction safety has always been the first priority in construction process. The common safety problem is the instability of the template support. In order to solve this problem, the digital image measurement technology has been contrived to support real-time monitoring system which can be triggered if the deformation value exceed the specified range. Thus the economic loss could be reduced to the lowest level.

Surface micromachined microengine as the driver for micromechanical gears

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia, E.J.; Sniegowski, J.J.

1995-05-01

The transmission of mechanical power is often accomplished through the use of gearing. The recently developed surface micromachined microengine provides us with an actuator which is suitable for driving surface micromachined geared systems. In this paper we will present aspects of the microengine as they relate to the driving of geared mechanisms, issues relating to the design of micro gear mechanisms, and details of a design of a microengine-driven geared shutter mechanism.

Applications of ANSYS/Multiphysics at NASA/Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Loughlin, Jim

2007-01-01

This viewgraph presentation reviews some of the uses that the ANSYS/Multiphysics system is used for at the NASA Goddard Space Flight Center. Some of the uses of the ANSYS system is used for is MEMS Structural Analysis of Micro-mirror Array for the James Web Space Telescope (JWST), Micro-shutter Array for JWST, MEMS FP Tunable Filter, AstroE2 Micro-calorimeter. Various views of these projects are shown in this presentation.

East Europe Report, Economic and Industrial Affairs, No. 2408.

DTIC Science & Technology

1983-06-08

these power plants ; —[the crisis resulting from] insufficient geological surveys (too few drill- ings, insufficient reserves’ analysis ), serious...which swallow the sardines of the local factories and plants . Regional banks pull their shutters down the moment a few ounces of gold raise or lower...ac- cordance with the multilateral program of R & D cooperation entitled "Diagnos- tics of WER Nuclear Power Plants ’ Operating State," a unique

Electronic Devices with Barrier Film and Process for Making Same

DTIC Science & Technology

1998-08-20

the barrier film on an atomic level where the barrier film is comprised of a plurality of contiguous monolayers, while FIG. 7B shows another...embodiment where the barrier film is comprised of a plurality of contiguous monolayers in which different monolayers thereof are formed of different...compound effusion cell, for example a barium fluoride, strontium fluoride or the like effusion cell, is provided at 32, and has a shutter 33. A

The Homogenized Energy Model (HEM) for Characterizing Polarization and Strains in Hysteretic Ferroelectric Materials: Material Properties and Uniaxial Model Development

DTIC Science & Technology

2012-01-01

auto focusing mechanisms, energy harvesting , and pico air vehicle design. Their advantages include nanometer positioning resolution, broadband frequency...high speed camera shutters and auto focusing mechanisms energy harvesting , and pico air vehicle design. Their advantages include nanometer positioning...THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Nomenclature d Piezoelectric constant (m/V = C/N) h

Evaluation of anti-freeze viscosity modifier for potential external tank applications

NASA Technical Reports Server (NTRS)

Lynn, R. O. L.

1981-01-01

Viscosity modifiers and gelling agents were evaluated in combination with ethylene glycol and dimethyl sulfoxide water eutectics. Pectin and agarose are found to gel these eutectics effectively in low concentration, but the anti-freeze protection afforded by these compositions is found to be marginal in simulations of the intended applications. Oxygen vent shutters and vertical metallic surfaces were simulated, with water supplied as a spray, dropwise, and by condensation from the air.

Knightsat Flight Design Review

DTIC Science & Technology

2007-08-03

spring loaded hinges were obtained from McMaster under part number 15205A42. The fasteners used to attach each shutter to its corresponding hinge were... Coefficient of thermal expansion) is fairly well matched to the cell’s germanium substrate. Copper is not a good choice since it expands and contracts...Temperature: K Ground Station Transmission Line Temp.: 290 K Ground Station Sky Temperature: 450 K G.S. Transmission Line Coefficient : 0.7943 Ground Station

Seasonal and interannual variability of fast ice extent in the southeastern Laptev Sea between 1999 and 2013

NASA Astrophysics Data System (ADS)

Selyuzhenok, V.; Krumpen, T.; Mahoney, A.; Janout, M.; Gerdes, R.

2015-12-01

Along with changes in sea ice extent, thickness, and drift speed, Arctic sea ice regime is characterized by a decrease of fast ice season and reduction of fast ice extent. The most extensive fast ice cover in the Arctic develops in the southeastern Laptev Sea. Using weekly operational sea ice charts produced by Arctic and Antarctic Research Institute (AARI, Russia) from 1999 to 2013, we identified five main key events that characterize the annual evolution of fast ice in the southeastern Laptev Sea. Linking the occurrence of the key events with the atmospheric forcing, bathymetry, freezeup, and melt onset, we examined the processes driving annual fast ice cycle. The analysis revealed that fast ice in the region is sensitive to thermodynamic processes throughout a season, while the wind has a strong influence only on the first stages of fast ice development. The maximal fast ice extent is closely linked to the bathymetry and local topography and is primarily defined by the location of shoals, where fast ice is likely grounded. The annual fast ice cycle shows significant changes over the period of investigation, with tendencies toward later fast ice formation and earlier breakup. These tendencies result in an overall decrease of the fast ice season by 2.8 d/yr, which is significantly higher than previously reported trends.

Genome-wide copy number variation analysis identified deletions in SFMBT1 associated with fasting plasma glucose in a Han Chinese population.

PubMed

Chung, Ren-Hua; Chiu, Yen-Feng; Hung, Yi-Jen; Lee, Wen-Jane; Wu, Kwan-Dun; Chen, Hui-Ling; Lin, Ming-Wei; Chen, Yii-Der I; Quertermous, Thomas; Hsiung, Chao A

2017-08-08

Fasting glucose and fasting insulin are glycemic traits closely related to diabetes, and understanding the role of genetic factors in these traits can help reveal the etiology of type 2 diabetes. Although single nucleotide polymorphisms (SNPs) in several candidate genes have been found to be associated with fasting glucose and fasting insulin, copy number variations (CNVs), which have been reported to be associated with several complex traits, have not been reported for association with these two traits. We aimed to identify CNVs associated with fasting glucose and fasting insulin. We conducted a genome-wide CNV association analysis for fasting plasma glucose (FPG) and fasting plasma insulin (FPI) using a family-based genome-wide association study sample from a Han Chinese population in Taiwan. A family-based CNV association test was developed in this study to identify common CNVs (i.e., CNVs with frequencies ≥ 5%), and a generalized estimating equation approach was used to test the associations between the traits and counts of global rare CNVs (i.e., CNVs with frequencies <5%). We found a significant genome-wide association for common deletions with a frequency of 5.2% in the Scm-like with four mbt domains 1 (SFMBT1) gene with FPG (association p-value = 2×10 -4 and an adjusted p-value = 0.0478 for multiple testing). No significant association was observed between global rare CNVs and FPG or FPI. The deletions in 20 individuals with DNA samples available were successfully validated using PCR-based amplification. The association of the deletions in SFMBT1 with FPG was further evaluated using an independent population-based replication sample obtained from the Taiwan Biobank. An association p-value of 0.065, which was close to the significance level of 0.05, for FPG was obtained by testing 9 individuals with CNVs in the SFMBT1 gene region and 11,692 individuals with normal copies in the replication cohort. Previous studies have found that SNPs in SFMBT1 are associated with blood pressure and serum urate concentration, suggesting that SFMBT1 may have functional implications in some metabolic-related traits.

Fast flows, ULF waves, firehose instability and their association in the Earth's mid-tail current sheet

NASA Astrophysics Data System (ADS)

Wang, C. P.; Xing, X.

2017-12-01

Ultra-Low Frequency (ULF) plasma waves with frequency range between 1 mHz to 10 Hz are widely observed in the Earth's magnetosphere and on the ground. In particular, Pi2 and Pc4 waves have been found to be closely related to many important dynamic processes in the magnetotail, e.g., fast flows (V > 300 km/s). Observations have shown Pi2 waves in association with fast flows in the near-Earth plasma sheet (X>-30 RE). However, in the mid-tail region, where fast flows are more frequently observed than those in the near-Earth magnetotail, this association has not been evaluated. Our preliminary study using ARTEMIS probes in the mid-tail region (X -60 RE) shows close association between Pi2 and Pc4 waves with the presence of fast flows. Strong connection between mid-tail Pi2 pulsations and high-latitude ground Pi2 signatures are also observed. Among many proposed theories for Pi2 wave, ballooning and firehose instabilities are plausible mechanisms in leading to the generation of plasma waves around Pi2 frequency band. Ballooning instability is widely admitted for fast flow associated Pi2 pulsations in the near-Earth region. However, firehose instability is expected to occur more easily in mid-tail and beyond due to the specific pressure anisotropy in that region. We examined the pressure anisotropy conditions and evaluated firehose instability condition for both Pi2 and Pc4 events in mid-tail. It is found that the plasma is unstable against firehose instability in association with the initiation of Pi2 and Pc4 waves. These may suggest that firehose instability can be a wave generation mechanism in the mid-tail region.

Fast-Acting Valve

NASA Technical Reports Server (NTRS)

Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

2003-01-01

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

A simple fast pulse gas valve using a dynamic pressure differential as the primary closing mechanism

NASA Astrophysics Data System (ADS)

Thomas, J. C.; Hwang, D. Q.; Horton, R. D.; Rogers, J. H.; Raman, R.

1993-06-01

In this article we describe a simple fast pulse gas valve developed for use in a plasma discharge experiment. The valve delivers 1017-1019 molecules per pulse varied by changing the voltage on the electromagnetic driver power supply. Valve pulse widths are observed to be less than 300 μs full width at half maximum with a rise time of less than 100 μs resulting in a maximum gas flow rate of ˜1022 molecules per second. An optical transmission technique was used to determine the mechanical opening and closing characteristics of the valve piston. A fast ionization gauge (FIG) was used for diagnosis of the temporal character of the gas pulse while the total gas throughput was determined by measuring the change in pressure per pulse in a small test chamber with a convectron tube gauge. Calibration of the FIG was accomplished by comparing the net change in pressure in a large chamber as measured by the FIG to the net change in pressure in a small test chamber as measured by the convectron tube gauge.

The performance of the MROI fast tip-tilt correction system

NASA Astrophysics Data System (ADS)

Young, John; Buscher, David; Fisher, Martin; Haniff, Christopher; Rea, Alexander; Seneta, Eugene; Sun, Xiaowei; Wilson, Donald; Farris, Allen; Olivares, Andres

2014-07-01

The fast tip-tilt (FTT) correction system for the Magdalena Ridge Observatory Interferometer (MROI) is being developed by the University of Cambridge. The design incorporates an EMCCD camera protected by a thermal enclosure, optical mounts with passive thermal compensation, and control software running under Xenomai real-time Linux. The complete FTT system is now undergoing laboratory testing prior to being installed on the first MROI unit telescope in the fall of 2014. We are following a twin-track approach to testing the closed-loop performance: tracking tip-tilt perturbations introduced by an actuated flat mirror in the laboratory, and undertaking end-to-end simulations that incorporate realistic higher-order atmospheric perturbations. We report test results that demonstrate (a) the high stability of the entire opto-mechanical system, realized with a completely passive design; and (b) the fast tip-tilt correction performance and limiting sensitivity. Our preliminary results in both areas are close to those needed to realise the ambitious stability and sensitivity goals of the MROI which aims to match the performance of current natural guide star adaptive optics systems.

MULTICHANNEL ANALYZER

DOEpatents

Kelley, G.G.

1959-11-10

A multichannel pulse analyzer having several window amplifiers, each amplifier serving one group of channels, with a single fast pulse-lengthener and a single novel interrogation circuit serving all channels is described. A pulse followed too closely timewise by another pulse is disregarded by the interrogation circuit to prevent errors due to pulse pileup. The window amplifiers are connected to the pulse lengthener output, rather than the linear amplifier output, so need not have the fast response characteristic formerly required.

Serious Allergic Reactions (Anaphylaxis)

MedlinePlus

... more of these body systems: skin digestive system respiratory system cardiovascular system For example, someone may feel tightness or closing in the throat (respiratory system) together with a fast heartbeat (cardiovascular system). Here ...

Oxybutynin

MedlinePlus

... does not close properly before birth), or other nervous system conditions that affect the bladder muscles. Oxybutynin is ... the body); myasthenia gravis (a disorder of the nervous system that causes muscle weakness); fast or irregular heartbeat; ...

Stroboscopic Goggles for Reduction of Motion Sickness

NASA Technical Reports Server (NTRS)

Reschke, M. F.; Somers, Jeffrey T.

2005-01-01

A device built around a pair of electronic shutters has been demonstrated to be effective as a prototype of stroboscopic goggles or eyeglasses for preventing or reducing motion sickness. The momentary opening of the shutters helps to suppress a phenomenon that is known in the art as retinal slip and is described more fully below. While a number of different environmental factors can induce motion sickness, a common factor associated with every known motion environment is sensory confusion or sensory mismatch. Motion sickness is a product of misinformation arriving at a central point in the nervous system from the senses from which one determines one s spatial orientation. When information from the eyes, ears, joints, and pressure receptors are all in agreement as to one s orientation, there is no motion sickness. When one or more sensory input(s) to the brain is not expected, or conflicts with what is anticipated, the end product is motion sickness. Normally, an observer s eye moves, compensating for the anticipated effect of motion, in such a manner that the image of an object moving relatively to an observer is held stationary on the retina. In almost every known environment that induces motion sickness, a change in the gain (in the signal-processing sense of gain ) of the vestibular system causes the motion of the eye to fail to hold images stationary on the retina, and the resulting motion of the images is termed retinal slip. The present concept of stroboscopic goggles or eyeglasses (see figure) is based on the proposition that prevention of retinal slip, and hence, the prevention of sensory mismatch, can be expected to reduce the tendency toward motion sickness. A device according to this concept helps to prevent retinal slip by providing snapshots of the visual environment through electronic shutters that are brief enough that each snapshot freezes the image on each retina. The exposure time for each snapshot is less than 5 ms. In the event that a higher rate of strobing is necessary for adequate viewing of the changing scene during rapid head movements, the rate of strobing (but not the exposure time) can be controlled in response to the readings of rate-of-rotation sensors attached to the device.

Fasting guidelines for diabetic children and adolescents

PubMed Central

Azad, Kiswhar; Mohsin, Fauzia; Zargar, Abdul Hamid; Zabeen, Bedowra; Ahmad, Jamal; Raza, Syed Abbas; Tayyeb, Samin; Bajaj, Sarita; Ishtiaq, Osama; Kalra, Sanjay

2012-01-01

Fasting during the month of Ramadan, the ninth month of Islamic lunar calendar, is obligatory for all healthy adult and adolescent Muslims from the age of 12 years. Fasting starts from early dawn (Sohur/Sehri) till sunset (Iftar). During this period one has to abstain from eating and drinking. Islam has allowed many categories of people to be exempted from fasting, for example, young children, travelers, the sick, the elderly, pregnant, and lactating women. According to expert opinion, patients with type 1 diabetes (type 1 DM) who fast during Ramadan are at a very high risk to develop adverse events. However, some experienced physicians are of the opinion that fasting during Ramadan is safe for type 1 DM patients, including adolescents and older children, with good glycemic control who do regular self-monitoring and are under close professional supervision. The strategies to ensure safety of type 1 diabetic adolescents who are planning to fast include the following: Ramadan-focused medical education, pre-Ramadan medical assessment, following a healthy diet and physical activity pattern, modification in insulin regimen, and blood glucose monitoring as advised by the physician. PMID:22837907

Obese mice on a high-fat alternate-day fasting regimen lose weight and improve glucose tolerance.

PubMed

Joslin, P M N; Bell, R K; Swoap, S J

2017-10-01

Alternate-day fasting (ADF) causes body weight (BW) loss in humans and rodents. However, it is not clear that ADF while maintaining a high-fat (HF) diet results in weight loss and the accompanying improvement in control of circulating glucose. We tested the hypotheses that a high-fat ADF protocol in obese mice would result in (i) BW loss, (ii) improved glucose control, (iii) fluctuating phenotypes on 'fasted' days when compared to 'fed' days and (iv) induction of torpor on 'fasted days'. We evaluated the physiological effects of ADF in diet-induced obese mice for BW, heart rate (HR), body temperature (T b ), glucose tolerance, insulin responsiveness, blood parameters (leptin, insulin, free fatty acids) and hepatic gene expression. Diet-induced obese male C57BL/6J mice lost one-third of their pre-diet BW while on an ADF diet for 10 weeks consisting of HF food. The ADF protocol improved glucose tolerance and insulin sensitivity, although mice on a fast day were less glucose tolerant than the same mice on a fed day. ADF mice on a fast day had low circulating insulin, but had an enhanced response to an insulin-assisted glucose tolerance test, suggesting the impaired glucose tolerance may be a result of insufficient insulin production. On fed days, ADF mice were the warmest, had a high HR and displayed hepatic gene expression and circulating leptin that closely mimicked that of mice fed an ad lib HF diet. ADF mice never entered torpor as assessed by HR and T b . However, on fast days, they were the coolest, had the slowest HR, and displayed hepatic gene expression and circulating leptin that closely mimicked that of Chow-Fed mice. Collectively, the ADF regimen with a HF diet in obese mice results in weight loss, improved blood glucose control, and daily fluctuations in selected physiological and biochemical parameters in the mouse. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

A Experimental Investigation of Fast Ion Confinement on the Isx-B Tokamak

NASA Astrophysics Data System (ADS)

Carnevali, Antonino

An experimental investigation of fast ion confinement was conducted on the ISX-B tokamak at the Oak Ridge National Laboratory to ascertain that the beam ion behavior is properly described by classical processes. Data were collected during tangential injection of H('0) beams (co-, counter -, and co- plus counter-) at power levels up to 1.9 MW in low plasma current (I(,p) = 80 to 215 kA) D('+) discharges. Experimental energy spectra of energetic charge-exchange neutrals along several sightlines in the torus equatorial plane are compared with the predictions of Fokker-Planck and orbit-following Monte Carlo calculations to verify the validity of classical theory. A further tool used in this investigation is the comparison of predicted and experimental beam-plasma neutron emission during injection of beams doped with 3% D('0). Both the fast neutral spectra and the beam-plasma neutron emission are in close agreement (within factors of <2) with the calculated values under a variety of plasma parameters, beam parameters, and injection geometries. Furthermore, measured decay rates of the beam-plasma neutron production following beam turn-off show that the beam slowing down --at energies close to the injection energy and in the plasma core-- is classical within a 30% uncertainty. These results demonstrate that classical theory describes well the behavior of the beam ions. Moreover, MHD activity is shown not to cause enhanced fast ion losses in the ISX-B. Also, beam additivity experiments indicate that the fast ion density in the plasma volume is proportional to the injected beam power P(,b). An unresolved issue is whether the central fast ion density is linear with P(,b). In addition, the analysis of charge-exchange spectra is critically evaluated. It is shown that the analysis need be integrated with a knowledge of the orbit topology to correctly interpret the spectra. Cases where the zero banana width, Fokker-Planck calculation is adequate/inadequate to predict fast neutral spectra and power deposited in the plasma are discussed.

Effects of fast ions on interchange modes in the Large Helical Device plasmas

NASA Astrophysics Data System (ADS)

Pinon, Jonhathan; Todo, Yasushi; Wang, Hao

2018-07-01

Effects of fast ions on the magnetohydrodynamic (MHD) instabilities in a Large Helical Device (LHD) plasma with the central beta value (=pressure normalized by the magnetic pressure) 4% have been investigated with hybrid simulations for energetic particles interacting with an MHD fluid. When fast ions are neglected, it is found that the dominant instability is an ideal interchange mode with the dominant harmonic m/n = 2/1, where m, n are respectively the poloidal and toroidal numbers. The spatial peak location of the m/n = 2/1 harmonic is close to the ι = 1/2 magnetic surface located at r/a = 0.29, where ι is the rotational transform and r/a is the normalized radius. The second unstable mode is a resistive interchange mode with m/n =3/2 that peaks at r/a = 0.65 nearby the ι = 2/3 surface, which grows more slowly than the m/n = 2/1 mode. The nonlinear coupling of the m/n = 3/2 and 2/1 mode results in the growth of the m/n = 5/3 mode and other modes leading to the global reduction and flattening of the pressure profile. When fast ions are considered with the central beta value 0.2% and the total pressure profile is kept the same, the ideal interchange mode with m/n = 2/1 located close to the plasma center is stabilized while the resistive interchange mode with m/n = 3/2 located far from the plasma center is less affected. The stabilization is attributed to the reduction of bulk pressure gradient, which is the dilution of the free energy source, because the energy transfer between the fast ions and the interchange modes is found to be negligible. For higher fast-ion pressure, Alfvén eigenmodes are destabilized by fast ions.

Fast Euler solver for transonic airfoils. I - Theory. II - Applications

NASA Technical Reports Server (NTRS)

Dadone, Andrea; Moretti, Gino

1988-01-01

Equations written in terms of generalized Riemann variables are presently integrated by inverting six bidiagonal matrices and two tridiagonal matrices, using an implicit Euler solver that is based on the lambda-formulation. The solution is found on a C-grid whose boundaries are very close to the airfoil. The fast solver is then applied to the computation of several flowfields on a NACA 0012 airfoil at various Mach number and alpha values, yielding results that are primarily concerned with transonic flows. The effects of grid fineness and boundary distances are analyzed; the code is found to be robust and accurate, as well as fast.

An inexpensive and fast method for infiltration coating of complex geometry matrices for ISOL production target applications

NASA Astrophysics Data System (ADS)

Kawai, Y.; Alton, G. D.; Bilheux, J.-C.

2005-12-01

An inexpensive, fast, and close to universal infiltration coating technique has been developed for fabricating fast diffusion-release ISOL targets. Targets are fabricated by deposition of finely divided (∼1 μm) compound materials in a paint-slurry onto highly permeable, complex structure reticulated-vitreous-carbon-foam (RVCF) matrices, followed by thermal heat treatment. In this article, we describe the coating method and present information on the physical integrity, uniformity of deposition, and matrix adherence of SiC, HfC and UC2 targets, destined for on-line use as targets at the Holifield Radioactive Ion Beam Facility (HRIBF).

Subframe Burst Gating for Raman Spectroscopy in Combustion

NASA Technical Reports Server (NTRS)

Kojima, Jun; Fischer, David; Nguyen, Quang-Viet

2010-01-01

We describe an architecture for spontaneous Raman scattering utilizing a frame-transfer CCD sensor operating in a subframe burst-gating mode to realize time-resolved combustion diagnostics. The technique permits all-electronic optical gating with microsecond shutter speeds 5 J.Ls) without compromising optical throughput or image fidelity. When used in conjunction with a pair of orthogonally polarized excitation lasers, the technique measures single-shot vibrational Raman scattering that is minimally contaminated by problematic optical background noise.

Growth of III-V films by control of MBE growth front stoichiometry

NASA Technical Reports Server (NTRS)

Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

1992-01-01

For the growth of strain-layer materials and high quality single and multiple quantum wells, the instantaneous control of growth front stoichiometry is critical. The process of the invention adjusts the offset or phase of molecular beam epitaxy (MBE) control shutters to program the instantaneous arrival or flux rate of In and As4 reactants to grow InAs. The interrupted growth of first In, then As4, is also a key feature.

Determination of the Emissivity of Materials

DTIC Science & Technology

1962-12-31

testing. The window is protected by a magnetically-ope-ated rolling disc shutter. Bakeout heaters are provided to outgas the chamber before testing...nitrogen cold trap over a period of two hours. During this period the chamber was baked out at 350 °F. The ion-gettering pump was then started and the...If the chamber had been contaminated by previous testing, it was baked out at 350 °F during pump-down. During testing, the chamber walls were cooled to

The Rocket Electric Field Sounding (REFS) Program: Prototype Design and Successful First Launch

DTIC Science & Technology

1992-01-15

insulators surrounding the stators, and stator edges themselves, are fully covered by the rotor , so that any effects of charge on the insulators are...Jumper performed a separate analysis of the aerodynamics (primarily the " Magnus effect ") induced by the relative rotation of rocket body and shell. The...significant advantages over an aircraft in simplicity and calibration. A single cylindrical rotor covering most of the payload acts as the shutter for all

The two types of stethoscope systems for respiration system diagnostics of the human body

NASA Astrophysics Data System (ADS)

Abashkin, Vladimir; Achimova, Elena

2003-12-01

An acoustic multimode fiber optic sensors for medical diagnostics based upon the shutter principle has been elaborated with semiconductor laser diode as light source. The construction and the method of component preparation are described. Other type of stethoscope is electrical one. Both stethoscopes are four channels. The kinetics and dynamic vibrations and sounds of the human body can be detected, acquired and then processing by personal computer for medical diagnostics.

Fluid circulating pump operated by same incident solar energy which heats energy collection fluid

NASA Technical Reports Server (NTRS)

Collins, E. R.

1980-01-01

The application of using a spacecraft solar powered pump terrestrially to reduce or eliminate the need for fossil fuel generated electricity for domestic solar hot water systems was investigated. A breadboard prototype model was constructed utilizing bimetals to convert thermal energy into mechanical motion by means of a toggle operated shutter mechanism. Although it did not meet expected thermal efficiency, the prototype model was sufficient to demonstrate the mechanical concept.

Electronic Devices with Cesium Barrier Film and Process for Making Same

DTIC Science & Technology

1998-08-20

interfacial structure of the barrier film on an atomic level where the barrier film is comprised of a plurality of contiguous monolayers, while FIG. 7B shows...another 20 embodiment where the barrier film is comprised of a plurality of contiguous monolayers in which different monolayers thereof are formed...compound effusion cell, for example a barium fluoride, strontium fluoride or the like effusion cell, is provided at 32, and has a shutter 33. A

Systematic Study of p-type Doping and Related Defects in III-Nitrides: Pathway toward a Nitride HBT

DTIC Science & Technology

2012-11-20

InGaN growth where an intermediate regime does not exist.40 Considering GaN molecular - beam epitaxy (MBE) growth phase diagrams such as those...1009 (2007). 44 S. D. Burnham, Improved Understanding and Control of Magnesium-Doped Gallium Nitride by Plasma Assisted Molecular Beam Epitaxy , in...reported using a modified form of molecular beam epitaxy (MBE) called Metal-Modulated Epitaxy (MME).11, 12 The details of this shuttered technique

New Modular Camera No Ordinary Joe

NASA Technical Reports Server (NTRS)

2003-01-01

Although dubbed 'Little Joe' for its small-format characteristics, a new wavefront sensor camera has proved that it is far from coming up short when paired with high-speed, low-noise applications. SciMeasure Analytical Systems, Inc., a provider of cameras and imaging accessories for use in biomedical research and industrial inspection and quality control, is the eye behind Little Joe's shutter, manufacturing and selling the modular, multi-purpose camera worldwide to advance fields such as astronomy, neurobiology, and cardiology.

Creating Ruddlesden-Popper phases by hybrid molecular beam epitaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haislmaier, Ryan C.; Stone, Greg; Alem, Nasim

2016-07-25

The synthesis of a 50 unit cell thick n = 4 Sr{sub n+1}Ti{sub n}O{sub 3n+1} (Sr{sub 5}Ti{sub 4}O{sub 13}) Ruddlesden-Popper (RP) phase film is demonstrated by sequentially depositing SrO and TiO{sub 2} layers in an alternating fashion using hybrid molecular beam epitaxy (MBE), where Ti was supplied using titanium tetraisopropoxide (TTIP). A detailed calibration procedure is outlined for determining the shuttering times to deposit SrO and TiO{sub 2} layers with precise monolayer doses using in-situ reflection high energy electron diffraction (RHEED) as feedback. Using optimized Sr and TTIP shuttering times, a fully automated growth of the n = 4 RP phase was carried outmore » over a period of >4.5 h. Very stable RHEED intensity oscillations were observed over the entire growth period. The structural characterization by X-ray diffraction and high resolution transmission electron microscopy revealed that a constant periodicity of four SrTiO{sub 3} perovskite unit cell blocks separating the double SrO rocksalt layer was maintained throughout the entire film thickness with a very little amount of planar faults oriented perpendicular to the growth front direction. These results illustrate that hybrid MBE is capable of layer-by-layer growth with atomic level precision and excellent flux stability.« less

Coupled tomography and distinct-element-method approach to exploring the granular media microstructure in a jamming hourglass

NASA Astrophysics Data System (ADS)

Tsukahara, M.; Mitrovic, S.; Gajdosik, V.; Margaritondo, G.; Pournin, L.; Ramaioli, M.; Sage, D.; Hwu, Y.; Unser, M.; Liebling, Th. M.

2008-06-01

We describe an approach for exploring microscopic properties of granular media that couples x-ray microtomography and distinct-element-method (DEM) simulations through image analysis. We illustrate it via the study of the intriguing phenomenon of instant arching in an hourglass (in our case a cylinder filled with a polydisperse mixture of glass beads that has a small circular shutter in the bottom). X-ray tomography provides three-dimensional snapshots of the microscopic conditions of the system both prior to opening the shutter, and thereafter, once jamming is completed. The process time in between is bridged using DEM simulation, which settles to positions in remarkably good agreement with the x-ray images. Specifically designed image analysis procedures accurately extract the geometrical information, i.e., the positions and sizes of the beads, from the raw x-ray tomographs, and compress the data representation from initially 5 gigabytes to a few tens of kilobytes per tomograph. The scope of the approach is explored through a sensitivity analysis to input data perturbations in both bead sizes and positions. We establish that accuracy of size—much more than position—estimates is critical, thus explaining the difficulty in considering a mixture of beads of different sizes. We further point to limits in the replication ability of granular flows away from equilibrium; i.e., the difficulty of numerically reproducing chaotic motion.

A Real-Time Imaging System for Stereo Atomic Microscopy at SPring-8's BL25SU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsushita, Tomohiro; Guo, Fang Zhun; Muro, Takayuki

2007-01-19

We have developed a real-time photoelectron angular distribution (PEAD) and Auger-electron angular distribution (AEAD) imaging system at SPring-8 BL25SU, Japan. In addition, a real-time imaging system for circular dichroism (CD) studies of PEAD/AEAD has been newly developed. Two PEAD images recorded with left- and right-circularly polarized light can be regarded as a stereo image of the atomic arrangement. A two-dimensional display type mirror analyzer (DIANA) has been installed at the beamline, making it possible to record PEAD/AEAD patterns with an acceptance angle of {+-}60 deg. in real-time. The twin-helical undulators at BL25SU enable helicity switching of the circularly polarized lightmore » at 10Hz, 1Hz or 0.1Hz. In order to realize real-time measurements of the CD of the PEAD/AEAD, the CCD camera must be synchronized to the switching frequency. The VME computer that controls the ID is connected to the measurement computer with two BNC cables, and the helicity information is sent using TTL signals. For maximum flexibility, rather than using a hardware shutter synchronizing with the TTL signal we have developed software to synchronize the CCD shutter with the TTL signal. We have succeeded in synchronizing the CCD camera in both the 1Hz and 0.1Hz modes.« less

Objective Evaluation of Visual Fatigue Using Binocular Fusion Maintenance

PubMed Central

Hirota, Masakazu; Morimoto, Takeshi; Kanda, Hiroyuki; Endo, Takao; Miyoshi, Tomomitsu; Miyagawa, Suguru; Hirohara, Yoko; Yamaguchi, Tatsuo; Saika, Makoto

2018-01-01

Purpose In this study, we investigated whether an individual's visual fatigue can be evaluated objectively and quantitatively from their ability to maintain binocular fusion. Methods Binocular fusion maintenance (BFM) was measured using a custom-made binocular open-view Shack–Hartmann wavefront aberrometer equipped with liquid crystal shutters, wherein eye movements and wavefront aberrations were measured simultaneously. Transmittance in the liquid crystal shutter in front of the subject's nondominant eye was reduced linearly, and BFM was determined from the transmittance at the point when binocular fusion was broken and vergence eye movement was induced. In total, 40 healthy subjects underwent the BFM test and completed a questionnaire regarding subjective symptoms before and after a visual task lasting 30 minutes. Results BFM was significantly reduced after the visual task (P < 0.001) and was negatively correlated with the total subjective eye symptom score (adjusted R2 = 0.752, P < 0.001). Furthermore, the diagnostic accuracy for visual fatigue was significantly higher in BFM than in the conventional test results (aggregated fusional vergence range, near point of convergence, and the high-frequency component of accommodative microfluctuations; P = 0.007). Conclusions These results suggest that BFM can be used as an indicator for evaluating visual fatigue. Translational Relevance BFM can be used to evaluate the visual fatigue caused by the new visual devices, such as head-mount display, objectively. PMID:29600117

Fast-acting valve actuator

DOEpatents

Cho, Nakwon

1980-01-01

A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

Impaired fasting blood glucose is associated to cognitive impairment and cerebral atrophy in middle-aged non-human primates

PubMed Central

Djelti, Fathia; Dhenain, Marc; Terrien, Jérémy; Picq, Jean-Luc; Hardy, Isabelle; Champeval, Delphine; Perret, Martine; Schenker, Esther; Epelbaum, Jacques; Aujard, Fabienne

2017-01-01

Age-associated cognitive impairment is a major health and social issue because of increasing aged population. Cognitive decline is not homogeneous in humans and the determinants leading to differences between subjects are not fully understood. In middle-aged healthy humans, fasting blood glucose levels in the upper normal range are associated with memory impairment and cerebral atrophy. Due to a close evolutional similarity to Man, non-human primates may be useful to investigate the relationships between glucose homeostasis, cognitive deficits and structural brain alterations. In the grey mouse lemur, Microcebus murinus, spatial memory deficits have been associated with age and cerebral atrophy but the origin of these alterations have not been clearly identified. Herein, we showed that, on 28 female grey mouse lemurs (age range 2.4-6.1 years-old), age correlated with impaired fasting blood glucose (rs=0.37) but not with impaired glucose tolerance or insulin resistance. In middle-aged animals (4.1-6.1 years-old), fasting blood glucose was inversely and closely linked with spatial memory performance (rs=0.56) and hippocampus (rs=−0.62) or septum (rs=−0.55) volumes. These findings corroborate observations in humans and further support the grey mouse lemur as a natural model to unravel mechanisms which link impaired glucose homeostasis, brain atrophy and cognitive processes. PMID:28039490

Impaired fasting blood glucose is associated to cognitive impairment and cerebral atrophy in middle-aged non-human primates.

PubMed

Djelti, Fathia; Dhenain, Marc; Terrien, Jérémy; Picq, Jean-Luc; Hardy, Isabelle; Champeval, Delphine; Perret, Martine; Schenker, Esther; Epelbaum, Jacques; Aujard, Fabienne

2016-12-28

Age-associated cognitive impairment is a major health and social issue because of increasing aged population. Cognitive decline is not homogeneous in humans and the determinants leading to differences between subjects are not fully understood. In middle-aged healthy humans, fasting blood glucose levels in the upper normal range are associated with memory impairment and cerebral atrophy. Due to a close evolutional similarity to Man, non-human primates may be useful to investigate the relationships between glucose homeostasis, cognitive deficits and structural brain alterations. In the grey mouse lemur, Microcebus murinus , spatial memory deficits have been associated with age and cerebral atrophy but the origin of these alterations have not been clearly identified. Herein, we showed that, on 28 female grey mouse lemurs (age range 2.4-6.1 years-old), age correlated with impaired fasting blood glucose (r s =0.37) but not with impaired glucose tolerance or insulin resistance. In middle-aged animals (4.1-6.1 years-old), fasting blood glucose was inversely and closely linked with spatial memory performance (r s =0.56) and hippocampus (r s =-0.62) or septum (r s =-0.55) volumes. These findings corroborate observations in humans and further support the grey mouse lemur as a natural model to unravel mechanisms which link impaired glucose homeostasis, brain atrophy and cognitive processes.

Monolithic Active Pixel Sensors

NASA Astrophysics Data System (ADS)

Lutz, P.

In close collaboration with the group from Strasbourg, Saclay has been developing fast monolithic active pixel sensors for future vertex detectors. This presentation gives some recent results from the MIMOSA serie, emphazising the participation of the group.

SAAO's new robotic telescope and WiNCam (Wide-field Nasmyth Camera)

NASA Astrophysics Data System (ADS)

Worters, Hannah L.; O'Connor, James E.; Carter, David B.; Loubser, Egan; Fourie, Pieter A.; Sickafoose, Amanda; Swanevelder, Pieter

2016-08-01

The South African Astronomical Observatory (SAAO) is designing and manufacturing a wide-field camera for use on two of its telescopes. The initial concept was of a Prime focus camera for the 74" telescope, an equatorial design made by Grubb Parsons, where it would employ a 61mmx61mm detector to cover a 23 arcmin diameter field of view. However, while in the design phase, SAAO embarked on the process of acquiring a bespoke 1-metre robotic alt-az telescope with a 43 arcmin field of view, which needs a homegrown instrument suite. The Prime focus camera design was thus adapted for use on either telescope, increasing the detector size to 92mmx92mm. Since the camera will be mounted on the Nasmyth port of the new telescope, it was dubbed WiNCam (Wide-field Nasmyth Camera). This paper describes both WiNCam and the new telescope. Producing an instrument that can be swapped between two very different telescopes poses some unique challenges. At the Nasmyth port of the alt-az telescope there is ample circumferential space, while on the 74 inch the available envelope is constrained by the optical footprint of the secondary, if further obscuration is to be avoided. This forces the design into a cylindrical volume of 600mm diameter x 250mm height. The back focal distance is tightly constrained on the new telescope, shoehorning the shutter, filter unit, guider mechanism, a 10mm thick window and a tip/tilt mechanism for the detector into 100mm depth. The iris shutter and filter wheel planned for prime focus could no longer be accommodated. Instead, a compact shutter with a thickness of less than 20mm has been designed in-house, using a sliding curtain mechanism to cover an aperture of 125mmx125mm, while the filter wheel has been replaced with 2 peripheral filter cartridges (6 filters each) and a gripper to move a filter into the beam. We intend using through-vacuum wall PCB technology across the cryostat vacuum interface, instead of traditional hermetic connector-based wiring. This has advantages in terms of space saving and improved performance. Measures are being taken to minimise the risk of damage during an instrument change. The detector is cooled by a Stirling cooler, which can be disconnected from the cooler unit without risking damage. Each telescope has a dedicated cooler unit into which the coolant hoses of WiNCam will plug. To overcome an inherent drawback of Stirling coolers, an active vibration damper is incorporated. During an instrument change, the autoguider remains on the telescope, and the filter magazines, shutter and detector package are removed as a single unit. The new alt-az telescope, manufactured by APM-Telescopes, is a 1-metre f/8 Ritchey-Chrétien with optics by LOMO. The field flattening optics were designed by Darragh O'Donoghue to have high UV throughput and uniform encircled energy over the 100mm diameter field. WiNCam will be mounted on one Nasmyth port, with the second port available for SHOC (Sutherland High-speed Optical Camera) and guest instrumentation. The telescope will be located in Sutherland, where an existing dome is being extensively renovated to accommodate it. Commissioning is planned for the second half of 2016.

Caution -- Beam Crossing Ahead

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barat, Kenneth L.

There are times when a laser beam needs to cross between tables or even go from one room to another. This presents an interesting traffic-flow and safety challenge to both the laser safety officer and laser user. Fortunately it is a challenge that has several solutions But the simplest solution may not be the best one. For example, the simplest way to get a beam from one optical table to another is just to put a sturdy tube around it. That's a permanent solution, and it completely contains the laser beam. While this is laser safe, there can be egressmore » issues if it blocks a walkway. One comment this author often hears is, 'We can just duck under the tube.' The fire marshal, as well as the laser safety officer, might have issues with this. Especially in the case of a darkened lab, a blocked walkway can present a hazard of its own. One good solution is to transport the beam from Point A to Point B through a fiberoptic cable, when that is possible. One should easily be able to run the fiber up and over any walkway or down through a conduit on the floor. An important concern often overlooked with fibers is a label at the termination end indicating disconnection may expose one to laser radiation. Suppose there's an experiment that is usually confined to a single optical table, but sometimes needs to expand to a second table. It's inconvenient to install a permanent tube between the tables, so some sort of temporary arrangement is desirable. I have often seen people casually lay a beam tube across support arms, and remove it when it's not needed. The problem with this approach is that there's no mechanism to prevent the beam from crossing if somebody's forgotten the tube, or if the tube gets knocked out of place. A better solution is a mechanism that only allows the beam to cross when the beam protection is in place. A swing shutter, or a guillotine and swing arm, are examples (Figures 1 and 2). Another alternative is a sensor, maybe a little microswitch, that activates a shutter to block the beam path if the beam tube is removed. Of course, there can be low-power beams that don't really need containment at all. There is no possibility of physical harm should somebody interrupt the beam. Even in these cases, though, the beam interruption is likely to disrupt the experiment. So I always suggest some sort of simple awareness device, like a sign, a swing gate, or a chain across the path. What about the case of a beam going from one room into the next? Here, the hazard is people in the second room being surprised when the people in the first room turn the laser on. To prevent that, the wise move is to let staff in the second room control beam entry. One approach is a shutter that can only be opened from the second room. A worthwhile safety addition is an illuminated light or LED to indicate shutter status. In conclusion, when beams need to cross walkways and or enter distant rooms, awareness and beam control are necessary and solutions exist.« less

Multimotor Transport in a System of Active and Inactive Kinesin-1 Motors

PubMed Central

Scharrel, Lara; Ma, Rui; Schneider, René; Jülicher, Frank; Diez, Stefan

2014-01-01

Long-range directional transport in cells is facilitated by microtubule-based motor proteins. One example is transport in a nerve cell, where small groups of motor proteins, such as kinesins and cytoplasmic dynein, work together to ensure the supply and clearance of cellular material along the axon. Defects in axonal transport have been linked to Alzheimer’s and other neurodegenerative diseases. However, it is not known in detail how multimotor-based cargo transport is impaired if a fraction of the motors are defective. To mimic impaired multimotor transport in vitro, we performed gliding motility assays with varying fractions of active kinesin-1 motors and inactive kinesin-1 motor mutants. We found that impaired transport manifests in multiple motility regimes: 1), a fast-motility regime characterized by gliding at velocities close to the single-molecule velocity of the active motors; 2), a slow-motility regime characterized by gliding at close-to zero velocity or full stopping; and 3), a regime in which fast and slow motilities coexist. Notably, the transition from the fast to the slow regime occurred sharply at a threshold fraction of active motors. Based on single-motor parameters, we developed a stochastic model and a mean-field theoretical description that explain our experimental findings. Our results demonstrate that impaired multimotor transport mostly occurs in an either/or fashion: depending on the ratio of active to inactive motors, transport is either performed at close to full speed or is out of action. PMID:25028878

Closed-loop control of renal perfusion pressure in physiological experiments.

PubMed

Campos-Delgado, D U; Bonilla, I; Rodríguez-Martínez, M; Sánchez-Briones, M E; Ruiz-Hernández, E

2013-07-01

This paper presents the design, experimental modeling, and control of a pump-driven renal perfusion pressure (RPP)-regulatory system to implement precise and relatively fast RPP regulation in rats. The mechatronic system is a simple, low-cost, and reliable device to automate the RPP regulation process based on flow-mediated occlusion. Hence, the regulated signal is the RPP measured in the left femoral artery of the rat, and the manipulated variable is the voltage applied to a dc motor that controls the occlusion of the aorta. The control system is implemented in a PC through the LabView software, and a data acquisition board NI USB-6210. A simple first-order linear system is proposed to approximate the dynamics in the experiment. The parameters of the model are chosen to minimize the error between the predicted and experimental output averaged from eight input/output datasets at different RPP operating conditions. A closed-loop servocontrol system based on a pole-placement PD controller plus dead-zone compensation was proposed for this purpose. First, the feedback structure was validated in simulation by considering parameter uncertainty, and constant and time-varying references. Several experimental tests were also conducted to validate in real time the closed-loop performance for stepwise and fast switching references, and the results show the effectiveness of the proposed automatic system to regulate the RPP in the rat, in a precise, accurate (mean error less than 2 mmHg) and relatively fast mode (10-15 s of response time).

2.1 meter (82 inch) Slip Ring By-Pass Project

NASA Astrophysics Data System (ADS)

Bryan, Corby B.

2006-12-01

2.1 meter (82 inch) Slip Ring By-Pass Project I will describe a project to bypass the old method of getting control communications above the rotation point of the McDonald Observatory 2.1 meter dome. The old method used slip rings that were implemented in the late 1930s. The new system uses wireless serial commands which allow the control lines to be taken off the slip rings, leaving only power and ground. I will describe how the concept was devised so the slip rings could be by-passed, what micro-controller system that was decided on and used, how the wireless units were set up and finally how the system was tested and put in place with only limited tasks to control. (I.E. the opening and closing of the shutters) We describe the advantages to making this upgrade and how it could benefit any telescope interested in upgrading its communication systems. This project was designed and tested in ten weeks during the McDonald Observatory REU and was supported under NSF AST-0243745. The system was designed so that it could be installed while running side by side with the current method of getting control to the above rotation point. The method is still in place being tested on the 2.1 meter telescope and will soon be fully implemented by the University of Texas McDonald Observatory OS staff.

The detection of the electric field vertical distribution underneath thundercloud: Principle and applications

NASA Technical Reports Server (NTRS)

Soula, Serge; Chauzy, Serge

1991-01-01

During the Florida 89 experiment at Kennedy Space Center, a new system was used in order to obtain the vertical distribution of the electric field underneath thunderstorms. It consists of a standard shutter field mill at ground level and five other field sensors suspended from a cable fastened to a tethered balloon located at an altitude of about 1000 meters. It also includes a reception station for telemetered information transmitted by sensors, a processing system in order to store data, and real time display on a screen to show the simultaneous field variations at each level along with the instantaneous electric field profile. The first results obtained show the great importance of the electric field vertical distribution. The field detected at a height of 600m reaches 65 kV/m while that at the surface does not exceed 5 kV/m. The field intensity in altitude is a better criterion for determining the right moment to launch a rocket devoted to flash triggering. Using Gauss's law, the simultaneous field variations at several levels are used in order to evaluate charge densities. Average values close to 1nC.m(-3) are calculated in layers up to 600 m. The calculation of different average charge densities leads to the characterization of the layer between cloud and ground just before the leader propagation in the case of cloud to ground flash.

Combinatorial preparation and characterization of thin-film multilayer electro-optical devices.

PubMed

Neuber, Christian; Bäte, Markus; Thelakkat, Mukundan; Schmidt, Hans-Werner; Hänsel, Helmut; Zettl, Heiko; Krausch, Georg

2007-07-01

In this article we present a setup for the combinatorial vapor deposition of thin-film multilayer devices as well as methods for the fast and efficient analytic screening of the libraries obtained. The preparation setup is based on a commercially available evaporation chamber equipped with various evaporation sources for both organic and metallic materials. The combinatorial approach is realized by the combination of a rotation stage for the substrate, a five-mask sampler, and an additional mask whose position can be deliberately varied along one axis during the evaporation process. The latter is used to evaporate linear as well as step gradients by continuous or stepwise movement of a shutter mask. The mask sampler allows to define the sectors of the library and to evaporate more complex structures, e.g., an electrode layout. Finally, the simultaneous evaporation of two or more materials enables us to produce layers of varying composition ratio in general and doped materials, in particular. For the control of the evaporation process we have developed an automation software, which is particularly helpful for complex library designs and which grants excellent repeatability of experiments. Efficient and fast characterization of the obtained libraries is realized by (i) a purely optical setup and (ii) an electro-optical setup. (i) The UV/vis reader FLASHScan 530 permits to map out the UV/vis absorbance or fluorescence of the whole library. The UV/vis absorbance is primarily used to determine layer thicknesses and to confirm thickness uniformity across larger regions. The fluorescence measurements are used to determine the composition of layers containing fluorescent dyes. (ii) For a detailed short- and long-term electro-optical analysis we have developed an automated measurement system, which allows the characterization of 8x8 optoelectronic devices and to study their degradation behavior. Both solar cells and organic light-emitting diodes can be tested. Finally, we have developed a data analysis software to extract characteristic values from the huge amount of data and with this facilitate the finding of systematic dependencies.

The Hills are Alive: Dynamic Ridges and Valleys in a Strike-Slip Environment

NASA Astrophysics Data System (ADS)

Duvall, A. R.; Tucker, G. E.

2014-12-01

Strike-slip fault zones have long been known for characteristic landforms such as offset and deflected rivers, linear strike-parallel valleys, and shutter ridges. Despite their common presence, questions remain about the mechanics of how these landforms arise or how their form varies as a function of slip rate, geomorphic process, or material properties. We know even less about what happens far from the fault, in drainage basin headwaters, as a result of strike-slip motion. Here we explore the effects of horizontal fault slip rate, bedrock erodibility, and hillslope diffusivity on river catchments that drain across an active strike-slip fault using the CHILD landscape evolution model. Model calculations demonstrate that lateral fault motion induces a permanent state of landscape disequilibrium brought about by fault offset-generated river lengthening alternating with abrupt shortening due to stream capture. This cycle of shifting drainage patterns and base level change continues until fault motion ceases thus creating a perpetual state of transience unique to strike-slip systems. Our models also make the surprising prediction that, in some cases, hillslope ridges oriented perpendicular to the fault migrate laterally in conjunction with fault motion. Ridge migration happens when slip rate is slow enough and/or diffusion and river incision are fast enough that the hillslopes can respond to the disequilibrium brought about by strike-slip motion. In models with faster slip rates, stronger rocks or less-diffusive hillslopes, ridge mobility is limited or arrested despite the fact that the process of river lengthening and capture continues. Fast-slip cases also develop prominent steep fault-facing hillslope facets proximal to the fault valley and along-strike topographic profiles with reduced local relief between ridges and valleys. Our results demonstrate the dynamic nature of strike-slip landscapes that vary systematically with a ratio of bedrock erodibility (K) and hillslope diffusivity (D) to the rate of horizontal advection of topography (v). These results also reveal a potential set of recognizable geomorphic signatures within strike-slip systems that should be looked to as indicators of fault activity and/or material properties.

Novel Optical Methods for Identification, Imaging, and Preservation of the Cavernous Nerves Responsible for Penile Erections during Prostate Cancer Surgery

DTIC Science & Technology

2009-03-01

wavelength, pulse energy, and pulse rate) to produce strongest and most rapid erectile response as measured by intracavernosal pressure in the penis ...PC Fiber Rod Housing Optics 5-mm-ID Port Probe Handle Probe Stem Enlarged View of Probe Tip Oscilloscope FunctionGenerator Thulium Fiber Laser Shutter...rapid erectile response as measured by intracavernosal pressure (ICP) in the penis . ICP values were increased from an initial range of 30-40 mmHg

Apollo 8 Mission image,Target of Opportunity (T/O) 10

NASA Image and Video Library

1968-12-21

Apollo 8,Moon,Target of Opportunity (T/O) 10, Various targets. Latitude 18 degrees South,Longitude 163.50 degrees West. Camera Tilt Mode: High Oblique. Direction: South. Sun Angle 12 degrees. Original Film Magazine was labeled E. Camera Data: 70mm Hasselblad; F-Stop: F-5.6; Shutter Speed: 1/250 second. Film Type: Kodak SO-3400 Black and White,ASA 40. Other Photographic Coverage: Lunar Orbiter 1 (LO I) S-3. Flight Date: December 21-27,1968.

Non-flickering 100 m RGB visible light communication transmission based on a CMOS image sensor.

PubMed

Chow, Chi-Wai; Shiu, Ruei-Jie; Liu, Yen-Chun; Liu, Yang; Yeh, Chien-Hung

2018-03-19

We demonstrate a non-flickering 100 m long-distance RGB visible light communication (VLC) transmission based on a complementary-metal-oxide-semiconductor (CMOS) camera. Experimental bit-error rate (BER) measurements under different camera ISO values and different transmission distances are evaluated. Here, we also experimentally reveal that the rolling shutter effect- (RSE) based VLC system cannot work at long distance transmission, and the under-sampled modulation- (USM) based VLC system is a good choice.

Interference-free optical detection for Raman spectroscopy

NASA Technical Reports Server (NTRS)

Fischer, David G (Inventor); Kojima, Jun (Inventor); Nguyen, Quang-Viet (Inventor)

2012-01-01

An architecture for spontaneous Raman scattering (SRS) that utilizes a frame-transfer charge-coupled device (CCD) sensor operating in a subframe burst gating mode to realize time-resolved combustion diagnostics is disclosed. The technique permits all-electronic optical gating with microsecond shutter speeds (<5 .mu.s), without compromising optical throughput or image fidelity. When used in conjunction with a pair of orthogonally-polarized excitation lasers, the technique measures time-resolved vibrational Raman scattering that is minimally contaminated by problematic optical background noise.

8. Historic view of the building: 'Warren Street from State ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Historic view of the building: 'Warren Street from State Street' ca. 1890. Courtesy of the Trenton Free Public Library. This shows the building before the True American's renovations of 1893. It is the three-story buildings, flanked by lower ones in the middle of the block. At the time of the photograph, the brick exterior was painted a light color and dark-colored louvered shutters flanked all the upper story windows. - 14 North Warren Street (Commercial Building), True American Building, Trenton, Mercer County, NJ

Groups of meteorite-producing meteoroids containing carbonaceous chondrite meteorites

NASA Astrophysics Data System (ADS)

Konovalova, N. A.; A.. Ibrohimov, A.; Kalashnikova, T. M.

2017-09-01

Proposed probable links of meteorite and meteorite-producing fireballs were been considered. Group associations between meteorite-producing meteoroids and meteorites were been determined for four carbonaceous chondrites Murchison, Maribo, Shutters Mill and Tagish Lake and potentially meteorite-producing bolides on the basis of links of their orbits. In result the several meteorite-producing sporadic slowly fireballs were found as the possible members of groups of four studied carbonaceous chondrite meteorites. One can presume that at present the identified groups may still contain large meteorite-dropping bodies.

Performance Analysis of Visible Light Communication Using CMOS Sensors.

PubMed

Do, Trong-Hop; Yoo, Myungsik

2016-02-29

This paper elucidates the fundamentals of visible light communication systems that use the rolling shutter mechanism of CMOS sensors. All related information involving different subjects, such as photometry, camera operation, photography and image processing, are studied in tandem to explain the system. Then, the system performance is analyzed with respect to signal quality and data rate. To this end, a measure of signal quality, the signal to interference plus noise ratio (SINR), is formulated. Finally, a simulation is conducted to verify the analysis.

Three mirror glancing incidence system for X-ray telescope

NASA Technical Reports Server (NTRS)

Hoover, R. B. (Inventor)

1974-01-01

A telescope suitable for soft X-ray astronomical observations consists of a paraboloid section for receiving rays at a grazing angle and a hyperboloid section which receives reflections from the paraboloid at a grazing angle and directs them to a predetermined point of focus. A second hyperboloid section is centrally located from the other two surfaces and positioned to reflect from its outer surface radiation which was not first reflected by the paraboloid. A shutter is included to assist in calibration.