light-weight spherical mirrors: Topics by WorldWideScience.org

Sample records for light-weight spherical mirrors

Light-weight spherical mirrors for Cherenkov detectors

CERN Document Server

Cisbani, E; Colilli, S; Crateri, R; Cusanno, F; De Leo, R; Fratoni, R; Frullani, S; Garibaldi, F; Giuliani, F; Gricia, M; Iodice, M; Iommi, R; Lagamba, L; Lucentini, M; Mostarda, A; Nappi, E; Pierangeli, L; Santavenere, F; Urciuoli, G M; Vernin, P

2003-01-01

Light-weight spherical mirrors have been appositely designed and built for the gas threshold Cherenkov detectors of the two Hall A spectrometers. The mirrors are made of a 1 mm thick aluminized plexiglass sheet, reinforced by a rigid backing consisting of a phenolic honeycomb sandwiched between two carbon fiber mats epoxy glued. The produced mirrors have a thickness equivalent to 0.55% of radiation length, and an optical slope error of about 5.5 mrad. These characteristics make these mirrors suitable for the implementation in Cherenkov threshold detectors. Ways to improve the mirror features are also discussed in view of their possible employment in RICH detectors.
Comparison of elliptical and spherical mirrors for the grasshopper monochromators at SSRL

International Nuclear Information System (INIS)

Waldhauer, A.P.

1989-01-01

A comparison of the performance of a spherical and elliptical mirror in the grasshopper monochromator is presented. The problem was studied by ray tracing and then tested using visible (λ=633 nm) laser light. Calculations using ideal optics yield an improvement in flux by a factor of up to 2.7, while tests with visible light show an increase by a factor of 5 because the old spherical mirror is compared to a new, perfect elliptical one. The FWHM of the measured focus is 90 μm with a spherical mirror, and 25 μm with an elliptical one. Elliptical mirrors have been acquired and are now being installed in the two grasshoppers at SSRL
Metrology and Alignment of Light Weight Grazing Incidence X-Ray Mirrors

Science.gov (United States)

Zhang, William; Content, David; Petre, Robert; Saha, Timo

2000-01-01

Metrology and alignment of light weight X-ray optics have been a challenge for two reasons: (1) that the intrinsic mirror quality and distortions caused by handling can not be easily separated, and (2) the diffraction limits of the visible light become a severe problem at the order of one arc-minute. Traditional methods of using a normal incident pencil or small parallel beam which monitors a tiny fraction of the mirror in question at a given time can not adequately monitor those distortions. We are developing a normal incidence setup that monitors a large fraction, if not the whole, of the mirror at any given time. It will allow us to align thin X-ray mirrors to-an accuracy of a few arc seconds or to a limit dominated by the mirror intrinsic quality.
Electrostatic axisymmetric mirror with removable spherical aberration

International Nuclear Information System (INIS)

Birmuzaev, S.B.; Serikbaeva, G.S.; Hizirova, M.A.

1999-01-01

The electrostatic axisymmetric mirror, assembled from three coaxial cylinders with an equal diameter d and under the potential v1, v2 and v3, was computed. The proportions of geometrical and electric parameters of the mirror, with which the spherical 3-order aberration may be eliminated, were determined. The computation outcomes of the case, when the focal power of the mirror is enough large and the object plane in the focus is out of its field, are presented (Fig. 1 - potentials proportion that makes elimination of the spherical aberration possible; Fig. 2 - the focus coordinates when the spherical aberration is eliminated). The geometrical values are presented by d, and the electric ones are presented by v1. The figures on the curves present a length of the second (middle) electrode. The zero point is located in the middle of the gap between the first and second electrodes The investigated mirror may be used as a lens for the transmission electron microscope
ULE design considerations for a 3m class light weighted mirror blank for E-ELT M5

Science.gov (United States)

Fox, Andrew; Hobbs, Tom; Edwards, Mary; Arnold, Matthew; Sawyer, Kent

2016-07-01

It is expected that the next generation of large ground based astronomical telescopes will need large fast-steering/tip-tilt mirrors made of ultra-lightweight construction. These fast-steering mirrors are used to continuously correct for atmospheric disturbances and telescope vibrations. An example of this is the European Extremely Large Telescope (E-ELT) M5 lightweight mirror, which is part of the Tip-Tilt/Field-Stabilization Unit. The baseline design for the E-ELT M5 mirror, as presented in the E-ELT Construction Proposal, is a closed-back ULE mirror with a lightweight core using square core cells. Corning Incorporated (Corning) has a long history of manufacturing lightweight mirror blanks using ULE in a closed-back construction, going back to the 1960's, and includes the Hubble Space Telescope primary mirror, Subaru Telescope secondary and tertiary mirrors, the Magellan I and II tertiary mirrors, and Kepler Space Telescope primary mirror, among many others. A parametric study of 1-meter class lightweight mirror designs showed that Corning's capability to seal a continuous back sheet to a light-weighted core structure provides superior mirror rigidity, in a near-zero thermal expansion material, relative to other existing technologies in this design space. Corning has investigated the parametric performance of several design characteristics for a 3-meter class lightweight mirror blank for the E-ELT M5. Finite Element Analysis was performed on several design scenarios to obtain weight, areal density, and first Eigen frequency. This paper presents an overview of Corning ULE and lightweight mirror manufacturing capabilities, the parametric performance of design characteristics for 1-meter class and 3-meter class lightweight mirrors, as well as the manufacturing advantages and disadvantages of those characteristics.
The Gaussian formula and spherical aberrations of static and relativistic curved mirrors from Fermat's principle

International Nuclear Information System (INIS)

Sutanto, Sylvia H; Tjiang, Paulus C

2011-01-01

The Gaussian formula and spherical aberrations of static and relativistic curved mirrors are analyzed using the optical path length (OPL) and Fermat's principle. The geometrical figures generated by the rotation of conic sections about their symmetry axes are considered for the shapes of the mirrors. By comparing the results in static and relativistic cases, it is shown that the focal lengths and the spherical aberration relations of the relativistic mirrors obey the Lorentz contraction. Further analysis of the spherical aberrations for both static and relativistic cases have resulted in information about the limits for the paraxial approximation, as well as for the minimum speed of the systems to reduce the spherical aberrations
Mirror, mirror on the wall

CERN Multimedia

2005-01-01

RICH 2, one of the two Ring Imaging Cherenkov detectors of the LHCb experiment, is being prepared to join the other detector elements ready for the first proton-proton collisions at LHC. The mirrors of the RICH2 detector are meticulously assembled in a clean room.In a large dark room, men in white move around an immense structure some 7 metres high, 10 metres wide and nearly 2.5 metres deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors. Each spherical mirror wall is made up of facets like a fly's eye. Twenty-eight individual thin glass mirrors will all point to the same point in space to within a few micro-radians. The development of these mirrors has been technically demanding : Ideally they should be massless, sturdy, precise and have high reflectivity. In practice, though not massless, they are made from a mere 6 mm thin gl...
Research on Measurement Accuracy of Laser Tracking System Based on Spherical Mirror with Rotation Errors of Gimbal Mount Axes

Science.gov (United States)

Shi, Zhaoyao; Song, Huixu; Chen, Hongfang; Sun, Yanqiang

2018-02-01

This paper presents a novel experimental approach for confirming that spherical mirror of a laser tracking system can reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy. By simplifying the optical system model of laser tracking system based on spherical mirror, we can easily extract the laser ranging measurement error caused by rotation errors of gimbal mount axes with the positions of spherical mirror, biconvex lens, cat's eye reflector, and measuring beam. The motions of polarization beam splitter and biconvex lens along the optical axis and vertical direction of optical axis are driven by error motions of gimbal mount axes. In order to simplify the experimental process, the motion of biconvex lens is substituted by the motion of spherical mirror according to the principle of relative motion. The laser ranging measurement error caused by the rotation errors of gimbal mount axes could be recorded in the readings of laser interferometer. The experimental results showed that the laser ranging measurement error caused by rotation errors was less than 0.1 μm if radial error motion and axial error motion were within ±10 μm. The experimental method simplified the experimental procedure and the spherical mirror could reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy of the laser tracking system.
Internal stray radiation measurement for cryogenic infrared imaging systems using a spherical mirror.

Science.gov (United States)

Tian, Qijie; Chang, Songtao; He, Fengyun; Li, Zhou; Qiao, Yanfeng

2017-06-10

Internal stray radiation is a key factor that influences infrared imaging systems, and its suppression level is an important criterion to evaluate system performance, especially for cryogenic infrared imaging systems, which are highly sensitive to thermal sources. In order to achieve accurate measurement for internal stray radiation, an approach is proposed, which is based on radiometric calibration using a spherical mirror. First of all, the theory of spherical mirror design is introduced. Then, the calibration formula considering the integration time is presented. Following this, the details regarding the measurement method are presented. By placing a spherical mirror in front of the infrared detector, the influence of internal factors of the detector on system output can be obtained. According to the calibration results of the infrared imaging system, the output caused by internal stray radiation can be acquired. Finally, several experiments are performed in a chamber with controllable inside temperatures to validate the theory proposed in this paper. Experimental results show that the measurement results are in good accordance with the theoretical analysis, and demonstrate that the proposed theories are valid and can be employed in practical applications. The proposed method can achieve accurate measurement for internal stray radiation at arbitrary integration time and ambient temperatures. The measurement result can be used to evaluate whether the suppression level meets the system requirement.
Super-light-weighted HB-Cesic® mirror cryogenic test

Science.gov (United States)

Devilliers, Christophe; Krödel, Matthias R.; Sodnik, Zoran; Robert, Patrick

2017-11-01

Future scientific space missions require ever more demanding large optics that work at cryogenic temperatures. In the frame of a Darwin assessment study conducted under ESA contract by TAS, the need of future very lightweight cryogenic mirrors with superior optical quality has been identified. Such mirrors need to be of size up to 3.5 m in diameter, with a mass of less than 250 kg (i.e. 25 kg/m2) and possess excellent optical quality at cryogenic temperature down to 40 K.
Rectangular-section mirror light pipes

Energy Technology Data Exchange (ETDEWEB)

Swift, P.D.; Lawlor, R. [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Smith, G.B.; Gentle, A. [Department of Applied Physics, University of Technology, Sydney, Broadway, NSW 2007 (Australia)

2008-08-15

Using an integrated-ray approach an expression for the transmission of rectangular section mirror light pipe (MLP) has been derived for the case of collimated light input. The transmittance and the irradiance distribution at the exit aperture of rectangular-section MLPs have been measured experimentally and calculated theoretically for the case of collimated light input. The results presented extend the description of MLPs from the cylindrical case. Measured and calculated transmittances and irradiance distributions are in good agreement. (author)
Multilayer mirror and foil filter AXUV diode arrays on CDX-U spherical torus

International Nuclear Information System (INIS)

Soukhanovskii, V. A.; Stutman, D.; Iovea, M.; Finkenthal, M.; Moos, H. W.; Munsat, T.; Jones, B.; Hoffman, D.; Kaita, R.; Majeski, R.

2001-01-01

Recent upgrades to CDX-U spherical torus diagnostics include two 10-channel AXUV diode arrays. The multilayer mirror (MLM) array measures the λ150 O VI brightness profile in the poloidal plane using the Mo/B 4 C synthetic multilayer structures as dispersive elements. The foil filter array has a tangential view and is equipped with interchangeable clear aperture, beryllium and titanium filters. This allows measurements of radiated power, O VI or C V radial distributions, respectively. The O VI and C V emissivity and the radiated power profiles are highly peaked. A Neoclassical impurity accumulation mechanism is considered as an explanation. For radiated power measurements in the T e ≤100 eV plasmas, photon energy dependent corrections must be used in order to account for nonlinear AXUV sensitivity in the range E phot ≤20 eV. The arrays are also used for characterization of resistive MHD phenomena, such as the low m modes, saw-tooth oscillations and internal reconnection events. Based on the successful operation of the diagnostics, a new ultra soft x-ray multilayer mirror diode AXUV diode array monitoring the 34 Aa emissivity distribution of C VI will be built and installed on the National Spherical Torus Experiment
Effect of solution temperature, light intensity and light in combination with sunlight using mirror duct on growth of leaf lettuce (Lactuca savtiva L. cv. 'Greenwave')

International Nuclear Information System (INIS)

Shimizu, H.; Kushida, M.; Fujinuma, W.; Sekine, M.; Kaiho, K.; Arai, H.; Shibusawa, S.

2004-01-01

Leaf lettuce crops (Lactuca sativa L. cv. 'Greenwave') were grown in a plant production system using a Mirror Duct which intensified sunlight and transferred it to the inside of buildings. This system was expected to reduce the operational energy and lighting cost. The experiments were conducted under four photosynthetic photon flux densities (PPF) of 140,160, 180, and 200 micro mol mE-2 sE-1, in two light conditions, fluorescent light only and fluorescent light plus sunlight transferred with the Mirror Duct, and were repeated five times in total from August 2002 to July 2003. Five different solution temperatures were finally obtained through all the experiments due to temperature changes inside the experiment facility. Variance was analyzed to estimate the effect of these environmental factors on the growth of leaf lettuce. It was found that the fresh weight of leaf lettuce increased as PPF increased and the rate of increase of weight was 0.6 to 1.0 g per unit PPF in both 17.4 deg C and 23.5 deg C solution temperatures; the solution temperature had a significant effect upon the fresh weight; and a difference in fresh weight at harvest of between 40 and 60 g was observed between 17.4 deg C and 23.5 deg C solution temperatures. The light containing 10% sunlight was not effective for increasing fresh weight at harvest compared to the fluorescent lamp
Carbon Fiber Mirror for a CubeSat Telescope

Science.gov (United States)

Kim, Young-Soo; Jang, Jeong Gyun; Kim, Jihun; Nam, Uk Won

2017-08-01

Telescope mirrors made by carbon fibers have been increasingly used especially for space applications, and they may replace the traditional glass mirrors. Glass mirrors are easy to fabricate, but needed to be carefully handled as they are brittle. Other materials have also been considered for telescope mirrors, such as metals, plastics, and liquids even. However glass and glass ceramics are still commonly and dominantly used.Carbon fiber has mainly been used for mechanical supports like truss structure and telescope tubes, as it is stiff and light-weight. It can also be a good material for telescope mirrors, as it has additional merits of non-brittle and very low thermal expansion. Therefore, carbon fiber mirror would be suitable for space telescopes which should endure the harsh vibration conditions during launch.A light-weight telescope made by carbon fiber has been designed for a small satellite which would have much less weight than conventional ones. In this poster, mirror materials are reviewed, and a design of carbon fiber telescope is presented and discussed.
Light and lightened mirrors for astronomy

Science.gov (United States)

Fappani, Denis

2008-07-01

For ground-based astronomy, more and more large telescopes are emerging all around the world. Similarly to space borne telescopes, for which the use of lightened optics has always been a baseline for purpose of mass reduction of payloads, same kinds of lightened/light mirrors are then now more and more intensively used also for ground-based instrumentation for astronomy, requiring larger and larger components. Through several examples of typical past realizations (class 0.5m-1m) for different astronomical projects requiring light or lightened mirrors for different reasons (optimisation of mass and stiffness, reduction of thermal inertia, increasing of dynamic performance for fast scanning purpose,....), the presentation will point out issues for lightening design, manufacturing and control of such parts, as well as brief overview of the corresponding existing "state of the art" for these technologies in SESO.
Process and device for manufacturing a spherical mirror for a solar powerstation lowered into the ground. Verfahren und Einrichtung zur Herstellung eines in das Erdreich eingelassenen Kugelspiegels fuer ein Sonnenkraftwerk

Energy Technology Data Exchange (ETDEWEB)

Ziemba, G.

1983-07-28

The purpose of the invention is to make the manufacture and the maintenance of a spherical mirror for a solar power station lowered into the ground simple and economical, even for large dimensions. According to the invention, this problem is solved by applying a hardening fixing layer to the surface of a prepared mould from one cantilever of a frame which can follow the spherical shape of the mirror, then spraying a transition layer onto this, and spraying a hardening elastic layer of foam on this, finally glueing the mirror layer on top. This process makes it possible to carry out fully automatic manufacture and maintenance of the spherical mirror from a frame. Foam may be added to the material forming the transition layer. (HWJ).
Single-axis four-mirror system: large spherical primary and small fields

Science.gov (United States)

Baranne, Andre

1998-08-01

A catoptric corrector of modest size can be used for large spherical primaries, easily integrated at the prime focus, this corrector gives back to the system, aspect and properties of 2-mirrors classical telescopes. In the last few years, progress in active and adaptative optics makes possible a lot of things, progress in measuring distances, new ideas on optical coatings, new materials and so on in a near future, all that makes the instrumentalist dreamy It is said that nobody knows today if the size of 3rd millennium telescopes will be limited or not by a theoretical, physical or technical phenomenon, thus let us imagine but with thoughtfulness because our projects will be surely restricted by financial considerations
Tailoring the chirality of light emission with spherical Si-based antennas.

Science.gov (United States)

Zambrana-Puyalto, Xavier; Bonod, Nicolas

2016-05-21

Chirality of light is of fundamental importance in several enabling technologies with growing applications in life sciences, chemistry and photodetection. Recently, some attention has been focused on chiral quantum emitters. Consequently, optical antennas which are able to tailor the chirality of light emission are needed. Spherical nanoresonators such as colloids are of particular interest to design optical antennas since they can be synthesized at a large scale and they exhibit good optical properties. Here, we show that these colloids can be used to tailor the chirality of a chiral emitter. To this purpose, we derive an analytic formalism to model the interaction between a chiral emitter and a spherical resonator. We then compare the performances of metallic and dielectric spherical antennas to tailor the chirality of light emission. It is seen that, due to their strong electric dipolar response, metallic spherical nanoparticles spoil the chirality of light emission by yielding achiral fields. In contrast, thanks to the combined excitation of electric and magnetic modes, dielectric Si-based particles feature the ability to inhibit or to boost the chirality of light emission. Finally, it is shown that dual modes in dielectric antennas preserve the chirality of light emission.
A novel mirror diversity receiver for indoor MIMO visible light

KAUST Repository

Park, Ki-Hong

2016-03-01

In this paper, we propose and study a non-imaging receiver design reducing the correlation of channel matrix for indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. Contrary to previous works, our proposed mirror diversity receiver (MDR) not only blocks the reception of light on one specific direction but also improves the channel gain on the other direction by receiving the light reflected by a mirror deployed between the photodetectors. We analyze the channel capacity and optimal height of mirror in terms of maximum channel capacity for a 2 -by-2 MIMO-VLC system in a 2-dimensional geometric model.We prove that this constructive and destructive effects in channel matrix resulting from our proposed MDR are more beneficial to obtain well-conditioned channel matrix which is suitable for implementing spatial-multiplexing MIMO-VLC systems in order to support high data rate.
Symmetry relationships for multiple scattering of polarized light in turbid spherical samples: theory and a Monte Carlo simulation.

Science.gov (United States)

Otsuki, Soichi

2016-02-01

This paper presents a theory describing totally incoherent multiple scattering of turbid spherical samples. It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in spherical samples. Monte Carlo simulations generate a reduced effective scattering Mueller matrix, which virtually satisfies reciprocity and mirror symmetry. The scattering matrix was factorized by using the symmetric decomposition in a predefined form, as well as the Lu-Chipman polar decomposition, approximately into a product of a pure depolarizer and vertically oriented linear retarding diattenuators. The parameters of these components were calculated as a function of the polar angle. While the turbid spherical sample is a pure depolarizer at low polar angles, it obtains more functions of the retarding diattenuator with increasing polar angle.

In-situ shearing interferometry of National Synchrotron Light Source mirrors

International Nuclear Information System (INIS)

Qian, S.N.; Rarback, H.; Shu, D.; Takacs, P.Z.

1987-01-01

In situ mirror distortion measurements were made with a lateral shearing interferometer on three mirrors in beam line X17T at the National Syn203hrotron Light Source. Lateral shearing interference is insensitive to vibrational motion in five of the six degrees of freedom, so it is well-suited for investigations in the synchrotron radiation (SR) environment. No distortion was seen in an uncooled silicon carbide mirror and in a colled copper alloy mirror on X17TB, but a change in the radius of an uncooled electroless nickel-plated aluminium cylinder mirror of about 6.2% was observed on X17TA. Angular vibrations in the 2 to 3 arc second range were easily observed on one of the beam lines, as was an overall mirror rotation in the arc second range
Focusing a laser beam by means of an off-centre parabolic mirror

International Nuclear Information System (INIS)

Rostaing, Michel.

In this study particular attention was paid to defining and optimizing a focusing system for concentrating a CO 2 laser beam (wave length lambda = 10.6 μm) on to a target containing a deuterium and tritium mixture. A digital study of the focusing of a spherical wave, in conjunction with the examination of the properties of reflecting surfaces led to the development of a focusing device using an off-centre parabolic mirror. Despite an aberration of 6 μm in the mirror, the lighting achieved experimentally in the plane of the circle of least scattering is 1.6 times greater than that achieved during the use of an NaCl spherical plane lense [fr
Adaptive aberration correction using a triode hyperbolic electron mirror

International Nuclear Information System (INIS)

Fitzgerald, J.P.S.; Word, R.C.; Koenenkamp, R.

2011-01-01

A converging electron mirror can be used to compensate spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a novel triode (three electrode) hyperbolic mirror as an improvement to the well-known diode (two electrode) hyperbolic mirror for aberration correction. A weakness of the diode mirror is a lack of flexibility in changing the chromatic and spherical aberration coefficients independently without changes in the mirror geometry. In order to remove this limitation, a third electrode can be added. We calculate the optical properties of the resulting triode mirror analytically on the basis of a simple model field distribution. We present the optical properties-the object/image distance, z 0 , and the coefficients of spherical and chromatic aberration, C s and C c , of both mirror types from an analysis of electron trajectories in the mirror field. From this analysis, we demonstrate that while the properties of both designs are similar, the additional parameters in the triode mirror improve the range of aberration that can be corrected. The triode mirror is also able to provide a dynamic adjustment range of chromatic aberration for fixed spherical aberration and focal length, or any permutation of these three parameters. While the dynamic range depends on the values of aberration correction needed, a nominal 10% tuning range is possible for most configurations accompanied by less than 1% change in the other two properties. -- Highlights: → Electrostatic aberration correction for chromatic and spherical aberration in electron optics. → Simultaneous correction of spherical and chromatic aberrations over a wide, adjustable range. → Analytic and quantitative description of correction parameters.
Beam line optics technologies series (7). Orthopedic treatment of sharp of light (reflecting mirror)

International Nuclear Information System (INIS)

Uruga, Tomoya; Nomura, Masaharu

2006-01-01

A reflecting mirror (mirror) is the most popular light device for orthopedic treatment of the shape of light. The paper explains the kinds of mirror for hard X-ray field and its applications in order to think the objects of mirror and how to adjust it when user experiment on the beam-line. The basic knowledge of reflection of X-ray, a use of mirror, the kinds of condenser mirror, the influence factors on the condenser size, arrangement of mirror in the hard X-ray beam-line, what kinds of mirror are necessary, evaluation of performance of mirror and adjustment, and troubles and measures are described. Layout in optics hutch at BL01B1 at SPring-8, refraction and total reflection of X-rays at surface, reflectivity of Rh and Pt with ideal surface as a function of photon energy, effects of surface roughness on reflectivity of Rh, calculated beam sizes for typical SPring-8 mirror as a function of magnification, schematic drawing of mirror, standard mirror system for vertical deflection in bending magnet beam-line, and observed and calculated reflectivity of Rh double mirror at BL01B1 at SPring-8 are illustrated. (S.Y)
Mirror boxes and mirror mounts for photophysics beamline

International Nuclear Information System (INIS)

Raja Rao, P.M.; Raja Sekhar, B.N.; Das, N.C.; Khan, H.A.; Bhattacharya, S.S.; Roy, A.P.

1996-01-01

Photophysics beamline makes use of one metre Seya-Namioka monochromator and two toroidal mirrors in its fore optics. The first toroidal mirror (pre mirror) focuses light originating from the tangent point of the storage ring onto the entrance slit of the monochromator and second toroidal mirror (post mirror) collects light from the exit slit of the monochromator and focuses light onto the sample placed at a distance of about one metre away from the 2nd mirror. To steer light through monochromator and to focus it on the sample of 1mm x 1mm size require precision rotational and translational motion of the mirrors and this has been achieved with the help of precision mirror mounts. Since Indus-1 operates at pressures less than 10 -9 m.bar, the mirror mounts should be manipulated under similar ultra high vacuum conditions. Considering these requirements, two mirror boxes and two mirror mounts have been designed and fabricated. The coarse movements to the mirrors are imparted from outside the mirror chamber with the help of x-y tables and precision movements to the mirrors are achieved with the help of mirror mounts. The UHV compatibility and performance of the mirror mounts connected to mirror boxes under ultra high vacuum condition is evaluated. The details of the design, fabrication and performance evaluation are discussed in this report. 5 refs., 9 figs., 1 tab
Analytic solution for a quartic electron mirror

Energy Technology Data Exchange (ETDEWEB)

Straton, Jack C., E-mail: straton@pdx.edu

2015-01-15

A converging electron mirror can be used to compensate for spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a diode (two-electrode) electrostatic mirror including the next term beyond the known hyperbolic shape. The latter is a solution of the Laplace equation to second order in the variables perpendicular to and along the mirror's radius (z{sup 2}−r{sup 2}/2) to which we add a quartic term (kλz{sup 4}). The analytical solution is found in terms of Jacobi cosine-amplitude functions. We find that a mirror less concave than the hyperbolic profile is more sensitive to changes in mirror voltages and the contrary holds for the mirror more concave than the hyperbolic profile. - Highlights: • We find the analytical solution for electron mirrors whose curvature has z4 dependence added to the usual z{sup 2} – r{sup 2}/2 terms. • The resulting Jacobi cosine-amplitude function reduces to the well-known cosh solution in the limit where the new term is 0. • This quartic term gives a mirror designer additional flexibility for eliminating spherical and chromatic aberrations. • The possibility of using these analytical results to approximately model spherical tetrode mirrors close to axis is noted.
Kirkpatrick-Baez microscope with spherical multilayer mirrors around 2.5keV photon energy

Science.gov (United States)

An, Ning; Du, Xuewei; Wang, Qiuping; Cao, Zhurong; Jiang, Shaoen; Ding, Yongkun

2014-09-01

A Kirkpatrick-Baez (KB) x-ray microscope has been developed for the diagnostics of inertial confinement fusion (ICF). The KB microscope system works around 2.5keV with the magnification of 20. It consists of two spherical multilayer mirrors. The grazing angle is 3.575° at 2.5keV. The influence of the slope error of optical components and the alignment errors is simulated by SHADOW software. The mechanical structure which can perform fine tuning is designed. Experiment result with Manson x-ray source shows that the spatial resolution of the system is about 3-4μm over a field of view of 200μm.
A novel mirror diversity receiver for indoor MIMO visible light communication systems

KAUST Repository

Park, Kihong

2016-12-24

In this paper, we propose and study a non-imaging receiver design reducing the correlation of channel matrix for indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. Contrary to previous works, our proposed mirror diversity receiver (MDR) not only blocks the reception of light on one specific direction but also improves the channel gain on the other direction by receiving the light reflected by a mirror deployed between the photodetectors. We analyze the channel capacity and optimal height of mirror in terms of maximum channel capacity for a 2 × 2 MIMO-VLC system in a 2-dimensional geometric model. We prove that this constructive and destructive effects in channel matrix resulting from our proposed MDR are more beneficial to obtain well-conditioned channel matrix which is suitable for implementing spatial-multiplexing MIMO-VLC systems in order to support high data rate.
Light mirror reflection combined with heating/cooling curves as a method of studying phase transitions in transparent and opaque petroleum products: Apparatus and theory

International Nuclear Information System (INIS)

Shishkin, Yu.L.

2007-01-01

A portable low weight low cost apparatus 'Phasafot' and method for determining pour and cloud points of petroleum products, as well as precipitation and melting temperatures of paraffins in both transparent (diesel fuels), semi-transparent (lube oils) and opaque (crude oils) samples are described. The method consists in illuminating the surface of a sample with an oblique light beam and registering the intensity of specularly reflected light while heating/cooling the sample in the temperature range of its structural transitions. The mirror reflection of a light beam from an ideally smooth liquid surface falls in intensity when the surface becomes rough (dim) due to crystal formation. Simultaneous recording of the temperature ramp curve and the mirror reflection curve enables the determination of the beginning and end of crystallization of paraffins in both transparent and opaque petroleum products. Besides, their rheological properties can be accurately determined by rocking or tilting the instrument while monitoring the sample movement via its mirror reflection
Evanescent light-wave atom mirrors, resonators, waveguides, and traps

International Nuclear Information System (INIS)

Dowling, J.P.; Gea-Banacloche, J.

1996-01-01

For many years, it has been known that light can be used to trap and manipulate small dielectric particles and atoms. In particular, the intense coherent light of lasers has been used to cool neutral atoms down to the micro-Kelvin and now even the nano-Kelvin regimes. At such low temperatures, the de Broglie wavelike character of the atoms becomes pronounced, making it necessary to treat the atoms as wave phenomena. To this end, the study of atom optics has recently developed, in which atom optical elements are fabricated in order to manipulate atoms, while utilizing and preserving the coherence and superposition properties inherent in their wavelike propagation. For example, there has been a concerted effort to study theoretically and produce experimentally the atom optic analogs of photonic optical elements, such as atom beam splitters, atom diffraction gratings, atom lenses, atom interferometers, and-last but not least-atom mirrors. It is light-induced atom mirrors, and their application to making atom resonators, waveguides, and traps, that we shall focus on in this chapter. 133 refs., 26 figs., 1 tab
Measuring the Dispersion in Laser Cavity Mirrors using White-Light Interferometry

Science.gov (United States)

2008-03-01

mirrors. Two AlGaInP (aluminum gallium indium phosphide ) diode lasers are aligned such that one is polarized vertically while one is polarized...linear crystals, where the index of refraction depends on beam intensity. Short pulses with high peak intensities are well 14 suited to induce the...MEASURING THE DISPERSION OF LASER CAVITY MIRRORS USING WHITE-LIGHT INTERFEROMETRY THESIS Allison S
Ultra-long magnetization needle induced by focusing azimuthally polarized beams with a spherical mirror.

Science.gov (United States)

Hang, Li; Luo, Kai; Fu, Jian; Chang, Yizhe; Wang, Ying; Chen, Peifeng

2018-03-20

Based on extended Richards-Wolf theory for axisymmetric surfaces and the inverse Faraday effect, we propose the generation of a purely longitudinal magnetization needle by focusing Gaussian annular azimuthally polarized beams with a spherical mirror. The needle obtained has a longitudinal length varying hundreds to thousands of wavelengths while keeping the lateral size under 0.4λ, and the corresponding aspect ratio can easily reach more than 2000. It may be the first time that a magnetization needle whose aspect ratio is over 500 has been achieved. The approximate analytical expressions of the magnetization needle are given, and the longitudinal length is tunable by changing the value of the angular thickness and the position of the annular beams.
Search for dark matter in the hidden-photon sector with a large spherical mirror

CERN Document Server

Veberic, Darko; Doebrich, Babette; Engel, Ralph; Jaeckel, Joerg; Kowalski, Marek; Lindner, Axel; Mathes, Hermann-Josef; Redondo, Javier; Roth, Markus; Schaefer, Christoph; Ulrich, Ralf

2015-01-01

If dark matter consists of hidden-sector photons which kinetically mix with regular photons, a tiny oscillating electric-field component is present wherever we have dark matter. In the surface of conducting materials this induces a small probability to emit single photons almost perpendicular to the surface, with the corresponding photon frequency matching the mass of the hidden photons. We report on a construction of an experimental setup with a large ~14 m2 spherical metallic mirror that will allow for searches of hidden-photon dark matter in the eV and sub-eV range by application of different electromagnetic radiation detectors. We discuss sensitivity and accessible regions in the dark matter parameter space.
Calibration of the mirror system in the HERA-B RICH

International Nuclear Information System (INIS)

Staric, Marko; Krizan, Peter

2008-01-01

The mirror system of the HERA-B ring imaging Cherenkov (RICH) counter consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the Cherenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method for mirror calibration is described and the effect of applying the required corrections on the Cherenkov angle resolution of the HERA-B RICH is discussed
A Low Cost Light Weight Polymer Derived Ceramic Telescope Mirror, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The primary purpose of this proposal is to develop and demonstrate a new technology for manufacturing an ultra-low-cost precision optical telescope mirror which can...
Mirror position determination for the alignment of Cherenkov Telescopes

Energy Technology Data Exchange (ETDEWEB)

Adam, J. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Ahnen, M.L. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Baack, D. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Balbo, M. [University of Geneva, ISDC Data Center for Astrophysics Chemin Ecogia 16, 1290 Versoix (Switzerland); Bergmann, M. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); Biland, A. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Blank, M. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); Bretz, T. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); RWTH Aachen (Germany); Bruegge, K.A.; Buss, J. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Dmytriiev, A. [University of Geneva, ISDC Data Center for Astrophysics Chemin Ecogia 16, 1290 Versoix (Switzerland); Domke, M. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Dorner, D. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); FAU Erlangen (Germany); Einecke, S. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Hempfling, C. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); and others

2017-07-11

Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures to map the faint Cherenkov light emitted in extensive air showers onto their image sensors. Segmented reflectors fulfill these needs using mass produced and light weight mirror facets. However, as the overall image is the sum of the individual mirror facet images, alignment is important. Here we present a method to determine the mirror facet positions on a segmented reflector in a very direct way. Our method reconstructs the mirror facet positions from photographs and a laser distance meter measurement which goes from the center of the image sensor plane to the center of each mirror facet. We use our method to both align the mirror facet positions and to feed the measured positions into our IACT simulation. We demonstrate our implementation on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).
Light-weight plastination.

Science.gov (United States)

Steinke, Hanno; Rabi, Suganthy; Saito, Toshiyuki; Sawutti, Alimjan; Miyaki, Takayoshi; Itoh, Masahiro; Spanel-Borowski, Katharina

2008-11-20

Plastination is an excellent technique which helps to keep the anatomical specimens in a dry, odourless state. Since the invention of plastination technique by von Hagens, research has been done to improve the quality of plastinated specimens. In this paper, we have described a method of producing light-weight plastinated specimens using xylene along with silicone and in the final step, substitute xylene with air. The finished plastinated specimens were light-weight, dry, odourless and robust. This method requires less use of resin thus making the plastination technique more cost-effective. The light-weight specimens are easy to carry and can easily be used for teaching.
Calibration of the mirror system in the HERA-B RICH

OpenAIRE

Starič, Marko; Križan, Peter

2007-01-01

The mirror system of the HERA-B RICH consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the \\v{C}erenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method is described and the effect of applying the required corrections on the \\v{C}erenkov angle resolution of the HERA-B RICH is disc...
A novel mirror diversity receiver for indoor MIMO visible light

KAUST Repository

Park, Ki-Hong; Alheadary, Wael G.; Alouini, Mohamed-Slim

2016-01-01

In this paper, we propose and study a non-imaging receiver design reducing the correlation of channel matrix for indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. Contrary to previous works, our proposed mirror
VCSELs and silicon light sources exploiting SOI grating mirrors

DEFF Research Database (Denmark)

Chung, Il-Sug; Mørk, Jesper

2012-01-01

In this talk, novel vertical-cavity laser structure consisting of a dielectric Bragg reflector, a III-V active region, and a high-index-contrast grating made in the Si layer of a silicon-on-insulator (SOI) wafer will be presented. In the Si light source version of this laser structure, the SOI...... the Bragg reflector. Numerical simulations show that both the silicon light source and the VCSEL exploiting SOI grating mirrors have superior performances, compared to existing silicon light sources and long wavelength VCSELs. These devices are highly adequate for chip-level optical interconnects as well...

Design of the science-fold mirrors for the Gemini telescopes

Science.gov (United States)

Peschel, Thomas; Damm, Christoph; Heilemann, Wolfgang

2000-07-01

As a part of the Acquisition and Guidance Unit for the Gemini project a light-weight, 50 cm flat mirror has been designed at the Fraunhofer Institute for Applied Optics and Precision Mechanics in Jena as a subcontractor of the Carl Zeiss Jena company. A light-weight design of the mirror and its mount was essential since the total mass of the whole assembly including the positioning system was limited to 50 kg while interferometric quality of the mirror surface was required for arbitrary orientation. The overall surface error was below 54 nm r.m.s. while 27 nm was achieved in the central part. The mirror was fabricated from low-expansion glass ceramics to avoid thermally induced deformations. By milling pockets into its rear surface the mass of the mirror was reduced by 70%. The mirror is mounted cinematically via six solid-state hinges to three steel levers. The levers are connected to the mount frame at their centers via ball-and- sphere joints. This arrangement determines the position of the mirror uniquely while it allows for the thermal expansion of the mount frame. The position of the mirror as well as its tilt around an axis perpendicular to the optical one may be controlled a precision of 20 micrometers and 3 arcsec, respectively. The tilt axis is driven directly by two high- torque motors. To avoid an excessive power consumption of the motors the torque of the mirror head to be compensated for by a counterweight mechanism. The mirror may be deployed into the optical path using spindle driven linear rails.
High Speed Magnetostrictive MEMS Actuated Mirror Deflectors, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The main goal of this proposal is to develop high speed magnetostrictive and MEMS actuators for rapidly deflecting or deforming mirrors. High speed, light-weight,...
Optical design of a reaction chamber for weakly absorbed light. II. Parallel mirrors, multitravel

International Nuclear Information System (INIS)

Devaney, J.J.; Finch, F.T.

1975-06-01

This report outlines the possibilities to be found using one or more diffraction-limited high-quality light beams to activate a weakly absorbing gas in a regime where the diffraction spread can be controlled by converging optical devices to within a ratio of √2 of the minimum at the beam waist (corresponding lengths between converging elements are within twice the Rayleigh range). Our designs use plane or cylindrical parallel mirrors down which a light beam is repeatedly reflected. In the first design variation, the beam is re-reflected up the parallel mirrors to the entrance aperture where it can be returned repeatedly for a number of multiply reflecting ''travels'' up and down the parallel mirror reaction chamber. In the second variation, the return of the beam after each multiply reflecting ''travel'' down the chamber is external to the chamber and is achieved by two mirror reflections. For diffraction control the return mirrors can be made converging. For multiple laser excitation, any of the external return mirrors can be replaced by a laser. The advantage of these designs is a high degree of uniformity of chamber illumination with a reasonably high number of passes. Drawbacks of the designs are the large space needed for beam return (many tens of meters for some parameters) and (common to all high optical quality chambers) the figuring and reflectivity demands on the mirrors. (U.S.)
A Novel Mirror-Aided Non-imaging Receiver for Indoor 2x2 MIMO Visible Light Communication Systems

KAUST Repository

Park, Kihong

2017-06-07

Indoor visible light communication (VLC) systems are now possible because of advances in light emitting diode and laser diode technologies. These lighting technologies provide the foundation for multiple-input multiple-output (MIMO) data transmission through visible light. However, the channel matrix can be strongly correlated in indoor MIMO-VLC systems, preventing parallel data streams from being decoded. Here, in $2\\\\times 2$ MIMO-VLC systems, we describe a mirror diversity receiver (MDR) design that reduces the channel correlation by both blocking the reception of light from one specific direction and improving the channel gain from light from another direction by utilizing a double-sided mirror deployed between the receiver\\'s photodetectors. We report on the channel capacity of the MDR system and the optimal height of its mirrors in terms of maximum channel capacity. We also derived analytic results on the effect of rotation on MDR\\'s performance. Based on numerical and experimental results, we show that the double-sided mirror has both constructive and destructive effects on the channel matrix. Our design can be used with previously described non-imaging systems to improve the performance of indoor VLC systems.
Research on large-aperture primary mirror supporting way of vehicle-mounted laser communication system

Science.gov (United States)

Meng, Lixin; Meng, Lingchen; Zhang, Yiqun; Zhang, Lizhong; Liu, Ming; Li, Xiaoming

2018-01-01

In the satellite to earth laser communication link, large-aperture ground laser communication terminals usually are used in order to realize the requirement of high rate and long distance communication and restrain the power fluctuation by atmospheric scintillation. With the increasing of the laser communication terminal caliber, the primary mirror weight should also be increased, and selfweight, thermal deformation and environment will affect the surface accuracy of the primary mirror surface. A high precision vehicular laser communication telescope unit with an effective aperture of 600mm was considered in this paper. The primary mirror is positioned with center hole, which back is supported by 9 floats and the side is supported by a mercury band. The secondary mirror adopts a spherical adjusting mechanism. Through simulation analysis, the system wave difference is better than λ/20 when the primary mirror is in different dip angle, which meets the requirements of laser communication.
Developmental long trace profiler using optimally aligned mirror based pentaprism

International Nuclear Information System (INIS)

Barber, Samuel K.; Morrison, Gregory Y.; Yashchuk, Valeriy V.; Gubarev, Mikhail V.; Geckeler, Ralf D.; Buchheim, Jana; Siewert, Frank; Zeschke, Thomas

2010-01-01

A low-budget surface slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought into operation at the Advanced Light Source Optical Metrology Laboratory (Nucl. Instr. and Meth. A 616, 212-223 (2010)). The instrument is based on a precisely calibrated autocollimator and a movable pentaprism. The capability of the DLTP to achieve sub-microradian surface slope metrology has been verified via cross-comparison measurements with other high-performance slope measuring instruments when measuring the same high-quality test optics. In the present work, a further improvement of the DLTP is achieved by replacing the existing bulk pentaprism with a specially designed mirror based pentaprism. A mirror based pentaprism offers the possibility to eliminate systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of a bulk pentaprism. We provide the details of the mirror based pentaprism design and describe an original experimental procedure for precision mutual alignment of the mirrors. The algorithm of the alignment procedure and its efficiency are verified with rigorous ray tracing simulations. Results of measurements of a spherically curved test mirror and a flat test mirror using the original bulk pentaprism are compared with measurements using the new mirror based pentaprism, demonstrating the improved performance.
Cesic: optomechanical technology last development results and new HBCesic highly light weighted space mirror development including corrective function 7th international conference on space optics, october 2008

Science.gov (United States)

Devilliers, Christophe; Kroedel, Mathias

2017-11-01

Thales-Alenia-Space and ECM has developed a new SiC ceramic composite to produce very lightweight space mirrors and structure. Cesicmade by ECM has been selected for its own intrinsic properties ( high specific Young modulus, high conductivity , low CTE, high strength for a ceramics) and its large manufacturing capabilities. Recently a full monolithic space instrument for earth observation, with a monolithic Cesicstructure and with Cesicmirrors has been designed, manufactured and space qualified and is now ready for launch. The Cesictelescope assembly has been tested under shock environment, vibration loads, and full qualification thermal environment. All these qualification tests were done directly on the flight model. Extensive development has been also performed to design, size, manufacture and test a very light weight reflector shell made as a single part. This 1 meter reflective shell has an areal density of less than 10 Kg/m2 has been manufactured with its surface grounded to the bi parabolic shape. Such challenging areal density has requested a very thin skin associated with a ribs thickness of less than 2mm. In order to demonstrate the high stability and strength of Cesicthe reflector has been tested successfully under very aggressive environment up to 350°C and also an acoustic test with flight representative levels was successfully performed. To produce future very lightweight space mirrors ECM develop with the support of Thales-Alenia-Space since some years an improved version of Cesicceramic, called HB-Cesic©. HB-Cesicmade by ECM is developed for its higher intrinsic properties, Young modulus, strength and especially its direct polishing capabilities down to 3 nm micro-roughness. One of the major targets for this development was also to overcome size limitations of the C/C raw material of currently around 1x1 m to produce mirror up to 3,5 m diameter out of a single C/C raw material block. Under ESA study a 600 mm mirror with a surface density of only
Smart Mirrors for Photorefractive Control of Light with Tim Bunning, RX - Agile Filters Application

Science.gov (United States)

2016-11-08

AFRL-AFOSR-UK-TR-2017-0008 Smart Mirrors for photorefractive control of light with Tim Bunning, RX-- Agile filters application Luciano De Sio...DATE (DD-MM-YYYY) 10-02-2017 2. REPORT TYPE Final 3. DATES COVERED (From - To) 01 Feb 2014 to 31 Jan 2016 4. TITLE AND SUBTITLE Smart Mirrors for...photorefractive control of light with Tim Bunning, RX-- Agile filters application 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-14-1-0050 5c. PROGRAM
Facile preparation and visible light photocatalytic activity of CdIn2S4 monodispersed spherical particles

International Nuclear Information System (INIS)

Mu Jin; Wei Qinglian; Yao Pingping; Zhao Xueling; Kang Shizhao; Li Xiangqing

2012-01-01

Highlights: ► CdIn 2 S 4 monodispersed spherical particles were prepared by a soft solution method. ► Mercaptoacetic acid was used as capping agent to hinder the fast crystal growth. ► Thioacetamide as sulfur source resulted in the slow growth of particles. ► CdIn 2 S 4 spheres showed high visible light photocatalytic activity. - Abstract: We developed a facile method to prepare CdIn 2 S 4 monodispersed spherical particles by using mercaptoacetic acid as capping agent and thioacetamide as sulfur source. The results indicated that the size and morphology of CdIn 2 S 4 particles were related to reaction time. The CdIn 2 S 4 spherical particles with an average size of about 236 nm and a narrow size distribution were formed after reacting for 7 h. The photocatalytic activity of as-synthesized CdIn 2 S 4 spherical particles was evaluated by the photocatalytic degradation of methyl orange under visible light illumination. The results showed that the photocatalytic activity increased with prolonging reaction time in the preparation of CdIn 2 S 4 spherical particles. The CdIn 2 S 4 spherical particles prepared after reacting for 7 h exhibited a 98% degradation efficiency of methyl orange after 15 min visible light irradiation.
Silicon-photonics light source realized by III-V/Si grating-mirror laser

DEFF Research Database (Denmark)

Chung, Il-Sug; Mørk, Jesper

2010-01-01

waveguide are made in the Si layer of a silicon-on-insulator wafer by using Si-electronics-compatible processing. The HCG works as a highly-reflective mirror for vertical resonance and at the same time routes light to the in-plane output waveguide. Numerical simulations show superior performance compared...... to existing silicon light sources....
Tensor-based cortical surface morphometry via weighted spherical harmonic representation.

Science.gov (United States)

Chung, Moo K; Dalton, Kim M; Davidson, Richard J

2008-08-01

We present a new tensor-based morphometric framework that quantifies cortical shape variations using a local area element. The local area element is computed from the Riemannian metric tensors, which are obtained from the smooth functional parametrization of a cortical mesh. For the smooth parametrization, we have developed a novel weighted spherical harmonic (SPHARM) representation, which generalizes the traditional SPHARM as a special case. For a specific choice of weights, the weighted-SPHARM is shown to be the least squares approximation to the solution of an isotropic heat diffusion on a unit sphere. The main aims of this paper are to present the weighted-SPHARM and to show how it can be used in the tensor-based morphometry. As an illustration, the methodology has been applied in the problem of detecting abnormal cortical regions in the group of high functioning autistic subjects.
Scopes for Schools: What do students know about light and mirrors?

Science.gov (United States)

Stassun, K.; Fabian, D.; Brissenden, G.; Lattis, J.

2002-05-01

The 'Scopes for Schools Project is an inquiry- and standards-based program that unites K-12 teachers, students, and professional astronomers to conduct outreach, curriculum development, and teacher professional development in astronomy. The main activities of S4S ('Scopes for Schools) are a teacher professional development workshop to increase teachers' astronomy content and pedagogical content knowledge, provide modeled curriculum activities, and the physical materials needed for doing astronomy in the classroom. We then build low-cost, high-quaility Dobsonian telescopes in the classroom with the students supplemented with fun, collaborative, inquiry-based astronomy activities. Finally, we help support the new teacher partners by assisting with star parties and astronomy club development. Previously, the curriculum development aspects of S4S have focused on post-telescope building activities, but in an attempt to provide a clear understanding of the optical properties of a telescope, we have developed an activity that explores how light interacts with a bare mirror. By grades 6-8, we have observed strongly held alternative conceptions about sight, the nature of light, and its interaction with reflective surfaces. We specifically and rigorously address this problem and the Benchmark ``Something can be "seen" when light waves emitted or reflected by it enter the eye-just as something can be "heard" when sound waves from it enter the ear.'' (Project 2061) with an activity that encourages students to manipulate a mirror and a light source to discover how images are formed. Students also gain experience with multiple variables in an experiment and the idea that it may not be possible to prevent outside factors from influencing the experiment. We discuss how this ``mirror activity'' relates to the cognitive development of students, the standards, and the greater S4S project. The 'Scopes for Schools Project has recieved funding from the Wisconsin Space Grant Consortium
Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

NARCIS (Netherlands)

Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Denisov, O.; Duic, V.; Ferrero, A.; Finger, M.; Finger, M.; Gayde, J. Ch; Giorgi, M.; Gobbo, B.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Panzieri, D.; Pesaro, G.; Polak, J.; Rocco, E.; Sbrizzai, G.; Schiavon, P.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.

2014-01-01

The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM)
Stress Free Multilayer Coating for High Resolution X-ray Mirrors

Data.gov (United States)

National Aeronautics and Space Administration — Most of X-ray optics research and development in the US is to build a high resolution, large collecting area and light-weight optic, namely an soft X-ray mirror for...
High-spin states in the A=39 mirror nuclei 39Ca and 39K

International Nuclear Information System (INIS)

Andersson, T.; Rudolph, D.; Fahlander, C.; Eberth, J.; Thomas, H.G.; Haslip, D.; Svensson, C.E.; Waddington, J.C.; LaFosse, D.R.; Sarantites, D.G.; Weintraub, W.; Wilson, J.N.; Brown, B.A.

1999-01-01

High-spin states of the mass A=39 mirror pair 39 K and 39 Ca were investigated via the fusion-evaporation reaction 28 Si+ 16 O at 125 MeV beam energy. The gammasphere array in conjunction with the 4π charged-particle detector array microball and neutron detectors was used to detect γ rays in coincidence with evaporated light particles. The results of the first high-spin study of the T z =-1/2 nucleus 39 Ca are discussed in terms of mirror symmetry and compared to spherical shell-model calculations in the 1d 3/2 -1f 7/2 configuration space. (orig.)
Relation between proton and neutron asymptotic normalization coefficients for light mirror nuclei and its relevance for nuclear astrophysics)

International Nuclear Information System (INIS)

Timofeyuk, N.K.; Johnson, R.C.; Descouvemont, P.

2005-01-01

In this talk, relation between proton and neutron Asymptotic Normalization Coefficients (ANCs) for light mirror nuclei will be discussed. This relation follows from charge symmetry of nucleon-nucleon interactions and is given by a simple approximate analytical formula which involves proton and neutron separation energies, charges of residual nuclei and the range of their strong interaction with the last nucleon. This relation is valid both for particle-bound mirror nuclear levels and for mirror pairs in which one of the levels is a narrow resonance. In the latter case, the width of this resonance is related to the ANC of its mirror particle-stable analog. Our theoretical study of mirror ANCs for several light nuclei within a framework of microscopic two-, three- and four-cluster models, have shown that the ratio of mirror ANCs changes as predicted by the simple approximate analytical formula. We will also compare the results from our microscopic calculations to the predictions of the single-particle model and discuss mirror symmetry of spectroscopic factors and single-particle ANCs. (author)
Hybrid simplified spherical harmonics with diffusion equation for light propagation in tissues

International Nuclear Information System (INIS)

Chen, Xueli; Sun, Fangfang; Yang, Defu; Ren, Shenghan; Liang, Jimin; Zhang, Qian

2015-01-01

Aiming at the limitations of the simplified spherical harmonics approximation (SP N ) and diffusion equation (DE) in describing the light propagation in tissues, a hybrid simplified spherical harmonics with diffusion equation (HSDE) based diffuse light transport model is proposed. In the HSDE model, the living body is first segmented into several major organs, and then the organs are divided into high scattering tissues and other tissues. DE and SP N are employed to describe the light propagation in these two kinds of tissues respectively, which are finally coupled using the established boundary coupling condition. The HSDE model makes full use of the advantages of SP N and DE, and abandons their disadvantages, so that it can provide a perfect balance between accuracy and computation time. Using the finite element method, the HSDE is solved for light flux density map on body surface. The accuracy and efficiency of the HSDE are validated with both regular geometries and digital mouse model based simulations. Corresponding results reveal that a comparable accuracy and much less computation time are achieved compared with the SP N model as well as a much better accuracy compared with the DE one. (paper)
Hybrid simplified spherical harmonics with diffusion equation for light propagation in tissues.

Science.gov (United States)

Chen, Xueli; Sun, Fangfang; Yang, Defu; Ren, Shenghan; Zhang, Qian; Liang, Jimin

2015-08-21

Aiming at the limitations of the simplified spherical harmonics approximation (SPN) and diffusion equation (DE) in describing the light propagation in tissues, a hybrid simplified spherical harmonics with diffusion equation (HSDE) based diffuse light transport model is proposed. In the HSDE model, the living body is first segmented into several major organs, and then the organs are divided into high scattering tissues and other tissues. DE and SPN are employed to describe the light propagation in these two kinds of tissues respectively, which are finally coupled using the established boundary coupling condition. The HSDE model makes full use of the advantages of SPN and DE, and abandons their disadvantages, so that it can provide a perfect balance between accuracy and computation time. Using the finite element method, the HSDE is solved for light flux density map on body surface. The accuracy and efficiency of the HSDE are validated with both regular geometries and digital mouse model based simulations. Corresponding results reveal that a comparable accuracy and much less computation time are achieved compared with the SPN model as well as a much better accuracy compared with the DE one.
Einstein's Mirror

Science.gov (United States)

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-10-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity.1-4 The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a constant velocity.5 Einstein showed an intriguing fact that the usual law of reflection would not hold in the case of a uniformly moving mirror, that is, the angles of incidence and reflection of the light would not equal each other. Later on, it has been shown that the law of reflection at a moving mirror can be obtained in various alternative ways,6-10 but none of them seems suitable for bringing this interesting subject into the high school classroom.
Mirror System for Collecting Thomson-Scattered Light in a Tangential Direction

NARCIS (Netherlands)

Barth, C. J.; Grobben, B. J. J.; Verhaag, G. C. H. M.

1994-01-01

We describe an optical system for collecting Thomson-scattering light in the tangential direction of a tokamak. The key part of the optics is a set of mirrors arranged as a Venetian blind. This system makes it possible to look around the corner of the tokamak vessel. Design considerations and test

Mirror-based broadband scanner with minimized aberration

Science.gov (United States)

Yu, Jiun-Yann; Tzeng, Yu-Yi; Huang, Chen-Han; Chui, Hsiang-Chen; Chu, Shi-Wei

2009-02-01

To obtain specific biochemical information in optical scanning microscopy, labeling technique is routinely required. Instead of the complex and invasive sample preparation procedures, incorporating spectral acquisition, which commonly requires a broadband light source, provides another mechanism to enhance molecular contrast. But most current optical scanning system is lens-based and thus the spectral bandwidth is limited to several hundred nanometers due to anti-reflection coating and chromatic aberration. The spectral range of interest in biological research covers ultraviolet to infrared. For example, the absorption peak of water falls around 3 μm, while most proteins exhibit absorption in the UV-visible regime. For imaging purpose, the transmission window of skin and cerebral tissues fall around 1300 and 1800 nm, respectively. Therefore, to extend the spectral bandwidth of an optical scanning system from visible to mid-infrared, we propose a system composed of metallic coated mirrors. A common issue in such a mirror-based system is aberrations induced by oblique incidence. We propose to compensate astigmatism by exchanging the sagittal and tangential planes of the converging spherical mirrors in the scanning system. With the aid of an optical design software, we build a diffraction-limited broadband scanning system with wavefront flatness better than λ/4 at focal plane. Combined with a mirror-based objective this microscopic system will exhibit full spectral capability and will be useful in microscopic imaging and therapeutic applications.
Design and fabrication of soft x-ray mirrors

Energy Technology Data Exchange (ETDEWEB)

Kawata, Masaru; Sasai, Hiroyuki; Sano, Kazuo [Shimadzu Corp., Production Engineering Laboratory, Kyoto (Japan)

2000-03-01

Soft x-ray photoelectron spectroscopic technology is important for measuring the chemical status of material surface in the LSI manufacturing process. We report on non-spherical mirrors focusing laser-induced plasma soft x-ray to fine sample surface. We designed toric and ellipsoidal mirror as soft x-ray condensing means, simulated focusing image, manufactured mirror surface on fused quartz substrate, and measured form accuracy. (author)
LIGHT-WEIGHT LOAD-BEARING STRUCTURE

DEFF Research Database (Denmark)

2009-01-01

The invention relates to a light-weight load-bearing structure (1) with optimized compression zone (2), where along one or more compression zones (2) in the structure (1) to be cast a core (3) of strong concrete is provided, which core (3) is surrounded by concrete of less strength (4) compared...... to the core (3) of strong concrete. The invention also relates to a method of casting of light-weight load-bearing structures (1) with optimized compression zone (2) where one or more channels, grooves, ducts, pipes and/or hoses (5) formed in the load-bearing structure (1) serves as moulds for moulding one...... or more cores (3) of strong concrete in the light-weight load-bearing structure (1)....
Proportioning of light weight concrete

DEFF Research Database (Denmark)

Palmus, Lars

1996-01-01

Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory......Development of a method to determine the proportions of the raw materials in light weight concrete made with leight expanded clay aggregate. The method is based on composite theory...
Einstein's Mirror

Science.gov (United States)

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-01-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…
Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

Science.gov (United States)

Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

2014-11-01

Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.
Segmented bimorph mirrors for adaptive optics: morphing strategy.

Science.gov (United States)

Bastaits, Renaud; Alaluf, David; Belloni, Edoardo; Rodrigues, Gonçalo; Preumont, André

2014-08-01

This paper discusses the concept of a light weight segmented bimorph mirror for adaptive optics. It focuses on the morphing strategy and addresses the ill-conditioning of the Jacobian of the segments, which are partly outside the optical pupil. Two options are discussed, one based on truncating the singular values and one called damped least squares, which minimizes a combined measure of the sensor error and the voltage vector. A comparison of various configurations of segmented mirrors was conducted; it is shown that segmentation sharply increases the natural frequency of the system with limited deterioration of the image quality.
Design rules for a compact and low-cost optical position sensing of MOEMS tilt mirrors based on a Gaussian-shaped light source

Science.gov (United States)

Baumgart, Marcus; Tortschanoff, Andreas

2013-05-01

A tilt mirror's deflection angle tracking setup is examined from a theoretical point of view. The proposed setup is based on a simple optical approach and easily scalable. Thus, the principle is especially of interest for small and fast oscillating MEMS/MOEMS based tilt mirrors. An experimentally established optical scheme is used as a starting point for accurate and fast mirror angle-position detection. This approach uses an additional layer, positioned under the MOEMS mirror's backside, consisting of a light source in the center and two photodetectors positioned symmetrical around the center. The mirror's back surface is illuminated by the light source and the intensity change due to mirror tilting is tracked via the photodiodes. The challenge of this method is to get a linear relation between the measured intensity and the current mirror tilt angle even for larger angles. State-of-the-art MOEMS mirrors achieve angles up to ±30°, which exceeds the linear angle approximations. The use of an LED, small laser diode or VCSEL as a lightsource is appropriate due to their small size and inexpensive price. Those light sources typically emit light with a Gaussian intensity distribution. This makes an analytical prediction of the expected detector signal quite complicated. In this publication an analytical simulation model is developed to evaluate the influence of the main parameters for this optical mirror tilt-sensor design. An easy and fast to calculate value directly linked to the mirror's tilt-angle is the "relative differential intensity" (RDI = (I1 - I2) / (I1 + I2)). Evaluation of its slope and nonlinear error highlights dependencies between the identified parameters for best SNR and linearity. Also the energy amount covering the detector area is taken into account. Design optimizing rules are proposed and discussed based on theoretical considerations.
Adaptive metal mirror for high-power CO2 lasers

Science.gov (United States)

Jarosch, Uwe-Klaus

1996-08-01

Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.
Speckle-based portable device for in-situ metrology of x-ray mirrors at Diamond Light Source

Science.gov (United States)

Wang, Hongchang; Kashyap, Yogesh; Zhou, Tunhe; Sawhney, Kawal

2017-09-01

For modern synchrotron light sources, the push toward diffraction-limited and coherence-preserved beams demands accurate metrology on X-ray optics. Moreover, it is important to perform in-situ characterization and optimization of X-ray mirrors since their ultimate performance is critically dependent on the working conditions. Therefore, it is highly desirable to develop a portable metrology device, which can be easily implemented on a range of beamlines for in-situ metrology. An X-ray speckle-based portable device for in-situ metrology of synchrotron X-ray mirrors has been developed at Diamond Light Source. Ultra-high angular sensitivity is achieved by scanning the speckle generator in the X-ray beam. In addition to the compact setup and ease of implementation, a user-friendly graphical user interface has been developed to ensure that characterization and alignment of X-ray mirrors is simple and fast. The functionality and feasibility of this device is presented with representative examples.
REFLECTED LIGHT CURVES, SPHERICAL AND BOND ALBEDOS OF JUPITER- AND SATURN-LIKE EXOPLANETS

Energy Technology Data Exchange (ETDEWEB)

Dyudina, Ulyana; Kopparla, Pushkar; Ingersoll, Andrew P.; Yung, Yuk L. [Division of Geological and Planetary Sciences, 150-21 California Institute of Technology, Pasadena, CA 91125 (United States); Zhang, Xi [University of California Santa Cruz 1156 High Street, Santa Cruz, CA 95064 (United States); Li, Liming [Department of Physics, University of Houston, Houston, TX 77204 (United States); Dones, Luke [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder CO 80302 (United States); Verbiscer, Anne, E-mail: ulyana@gps.caltech.edu [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)

2016-05-10

Reflected light curves observed for exoplanets indicate that a few of them host bright clouds. We estimate how the light curve and total stellar heating of a planet depends on forward and backward scattering in the clouds based on Pioneer and Cassini spacecraft images of Jupiter and Saturn. We fit analytical functions to the local reflected brightnesses of Jupiter and Saturn depending on the planet’s phase. These observations cover broadbands at 0.59–0.72 and 0.39–0.5 μ m, and narrowbands at 0.938 (atmospheric window), 0.889 (CH4 absorption band), and 0.24–0.28 μ m. We simulate the images of the planets with a ray-tracing model, and disk-integrate them to produce the full-orbit light curves. For Jupiter, we also fit the modeled light curves to the observed full-disk brightness. We derive spherical albedos for Jupiter and Saturn, and for planets with Lambertian and Rayleigh-scattering atmospheres. Jupiter-like atmospheres can produce light curves that are a factor of two fainter at half-phase than the Lambertian planet, given the same geometric albedo at transit. The spherical albedo is typically lower than for a Lambertian planet by up to a factor of ∼1.5. The Lambertian assumption will underestimate the absorption of the stellar light and the equilibrium temperature of the planetary atmosphere. We also compare our light curves with the light curves of solid bodies: the moons Enceladus and Callisto. Their strong backscattering peak within a few degrees of opposition (secondary eclipse) can lead to an even stronger underestimate of the stellar heating.
Optical fabrication of lightweighted 3D printed mirrors

Science.gov (United States)

Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

2015-09-01

Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.
Glass-Coated Beryllium Mirrors for the LHCb RICH1 Detector

CERN Document Server

Barber, G J; Cameron, W; D'Ambrosio, C; Frei, C; Harnew, N; Head, R; Khimitch, Y P; Khmelnikov, V A; Loveridge, P W; Metlica, F; Obraztsov, V F; Piedigrossi, D; Sizenev, V; Kompozit Joint Stock Company, Moscow, Russia; Szczypka, P M; Ullaland, O; Vygosky, E; Websdale, D M

2007-01-01

The design, manufacture and testing of lightweight glass-coated beryllium spherical converging mirrors for the RICH1 detector of LHCb are described. The mirrors need to be lightweight to minimize the material budget and fluorocarbon-compatible to avoid degradation in the RICH1 C4F10 gas radiator. Results of the optical measurements for the small-sized prototypes and for the first full-sized prototype mirror are reported.
On the fundamental mode of the optical resonator with toroidal mirrors

Energy Technology Data Exchange (ETDEWEB)

Serednyakov, S.S.; Vinokurov, N.A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

1995-12-31

The fundamental mode of the optical resonator with the toroidal mirrors is investigated. The losses in such resonator with the on-axis holes are low in compare with the case of spherical mirrors. The use of this type of optical resonator is briefly discussed.
Spherical grating spectrometers

Science.gov (United States)

O'Donoghue, Darragh; Clemens, J. Christopher

2014-07-01

We describe designs for spectrometers employing convex dispersers. The Offner spectrometer was the first such instrument; it has almost exclusively been employed on satellite platforms, and has had little impact on ground-based instruments. We have learned how to fabricate curved Volume Phase Holographic (VPH) gratings and, in contrast to the planar gratings of traditional spectrometers, describe how such devices can be used in optical/infrared spectrometers designed specifically for curved diffraction gratings. Volume Phase Holographic gratings are highly efficient compared to conventional surface relief gratings; they have become the disperser of choice in optical / NIR spectrometers. The advantage of spectrometers with curved VPH dispersers is the very small number of optical elements used (the simplest comprising a grating and a spherical mirror), as well as illumination of mirrors off axis, resulting in greater efficiency and reduction in size. We describe a "Half Offner" spectrometer, an even simpler version of the Offner spectrometer. We present an entirely novel design, the Spherical Transmission Grating Spectrometer (STGS), and discuss exemplary applications, including a design for a double-beam spectrometer without any requirement for a dichroic. This paradigm change in spectrometer design offers an alternative to all-refractive astronomical spectrometer designs, using expensive, fragile lens elements fabricated from CaF2 or even more exotic materials. The unobscured mirror layout avoids a major drawback of the previous generation of catadioptric spectrometer designs. We describe laboratory measurements of the efficiency and image quality of a curved VPH grating in a STGS design, demonstrating, simultaneously, efficiency comparable to planar VPH gratings along with good image quality. The stage is now set for construction of a prototype instrument with impressive performance.
Optical systems for synchrotron radiation. Lecture 2. Mirror systems

International Nuclear Information System (INIS)

Howells, M.R.

1986-02-01

The process of reflection of VUV and x-radiation is summarized. The functions of mirrors in synchrotron beamlines are described, which include deflection, filtration, power absorption, formation of a real image, focusing, and collimation. Fabrication of optical surfaces for synchrotron radiation beamlines are described, and include polishing of a near spherical surface as well as bending a cylindrical surface to toroidal shape. The imperfections present in mirrors, aberrations and surface figure inaccuracy, are discussed. Calculation of the thermal load of a mirror in a synchrotron radiation beam and the cooling of the mirror are covered briefly. 50 refs., 7 figs
Metamaterial mirrors in optoelectronic devices

KAUST Repository

Esfandyarpour, Majid; Garnett, Erik C.; Cui, Yi; McGehee, Michael D.; Brongersma, Mark L.

2014-01-01

The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.
Metamaterial mirrors in optoelectronic devices

KAUST Repository

Esfandyarpour, Majid

2014-06-22

The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.
Optical Analysis of an Ultra-High resolution Two-Mirror Soft X-Ray Microscope

Science.gov (United States)

Shealy, David L.; Wang, Cheng; Hoover, Richard B.

1994-01-01

This work has summarized for a Schwarzschild microscope some relationships between numerical aperture (NA), magnification, diameter of the primary mirror, radius of curvature of the secondary mirror, and the total length of the microscope. To achieve resolutions better than a spherical Schwarzschild microscope of 3.3 Lambda for a perfectly aligned and fabricated system. it is necessary to use aspherical surfaces to control higher-order aberrations. For an NA of 0.35, the aspherical Head microscope provides diffraction limited resolution of 1.4 Lambda where the aspherical surfaces differ from the best fit spherical surface by approximately 1 micrometer. However, the angle of incidence varies significantly over the primary and the secondary mirrors, which will require graded multilayer coatings to operate near peak reflectivities. For higher numerical apertures, the variation of the angle of incidence over the secondary mirror surface becomes a serious problem which must be solved before multilayer coatings can be used for this application. Tolerance analysis of the spherical Schwarzschild microscope has shown that water window operations will require 2-3 times tighter tolerances to achieve a similar performance for operations with 130 A radiation. Surface contour errors have been shown to have a significant impact on the MTF and must be controlled to a peak-to-valley variation of 50-100 A and a frequency of 8 periods over the surface of a mirror.
AFOCAL SYSTEMS FORMED BY MIRROR OFF-AXIS PARABOLOID

Directory of Open Access Journals (Sweden)

N. K. Artiukhina

2017-01-01

Full Text Available Mirror systems make it possible to reduce device dimensions and its weight while preserving high input aperture and these systems are characterized by a number of other advantages. Their significant disadvantage is a central screening of an entrance pupil that leads to lower image quality. The paper contains description of the investigations on afocal systems formed by eccentrically cut-out mirror paraboloids (off-axis mirrors where aperture diaphragm is displaced in the meridian plane for a defined value and a central field point is located on the optical axis. The canonic Mersenne systems are accepted as base schemas (modules for these compositions. The paper considers two types of such systems: visible increases – Г > 0 and Г < 0. Algorithms for calculation of centered afocal systems with two and four reflections have been written in the paper and the systems are free from spherical aberration, coma, astigmatism when an input pupil is located in superimposed focal planes of all parabolic mirrors. An aberration in curvature image has been additionally corrected in three-mirror quart-parabolic scheme which is a combination of two classical telescopic Mersenne systems. The paper presents schemes and calculation results. Two-mirror schemes with non-screened input pupil have been studied in the paper and in this case all the system remains centered and an aperture diaphragm is decentered for the distance Cm which is commensurable with the diaphragm size. The paper contains description of the investigated afocal schemes with four reflections from off-axis mirror paraboloids, a prepared algorithm for calculation, the obtained formulas for making combination of canonic afocal systems formed by two mirrors. Computer simulation in software environment Opal and Zemax has been carried out in the paper. Basic description has been prepared while using two alternative methods for the class of decentered systems and aberration characteristics and

Behavior of self-confined spherical layer of light radiation in the air atmosphere

International Nuclear Information System (INIS)

Torchigin, V.P.; Torchigin, A.V.

2004-01-01

Behavior of thin spherical layer of intensive light in an inhomogeneous atmosphere is considered. It is shown that the behavior is similar to puzzling and mysterious behavior of ball lightnings. Under assumption that ball lightning moves along the gradient of atmosphere air density process of ball lightning penetration in a salon of a flying airplane is analyzed
Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

Energy Technology Data Exchange (ETDEWEB)

Alexeev, M. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); INFN, Sezione di Trieste and University of Bari, Bari (Italy); Birsa, R. [INFN, Sezione di Trieste, Trieste (Italy); Bradamante, F.; Bressan, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Chiosso, M. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Ciliberti, P. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Dalla Torre, S. [INFN, Sezione di Trieste, Trieste (Italy); Denisov, O. [INFN, Sezione di Torino, Torino (Italy); Duic, V. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Ferrero, A. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Finger, M.; Finger, M. [Charles University, Prague (Czech Republic); JINR, Dubna (Russian Federation); Gayde, J.Ch. [CERN, European Organization for Nuclear Research, Geneva (Switzerland); Giorgi, M. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Gobbo, B.; Levorato, S. [INFN, Sezione di Trieste, Trieste (Italy); Maggiora, A. [INFN, Sezione di Torino, Torino (Italy); Martin, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Menon, G. [INFN, Sezione di Trieste, Trieste (Italy); Panzieri, D. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); and others

2014-12-01

The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM) photogrammetry-based method has been implemented to measure the alignment of individual mirrors which can be characterized by the center of curvature. The mirror wall reflects a regular grid of retroreflective strips placed inside the detector vessel. Then, the position of each mirror is determined from the image of the grid reflection. The images are collected by four cameras. Any small mirror misalignment results in changes of the grid lines’ positions in the image. The accuracy limits of the CLAM method were checked by laser interferometry and are below 0.1 mrad.
Spontaneous expression of mirror self-recognition in monkeys after learning precise visual-proprioceptive association for mirror images.

Science.gov (United States)

Chang, Liangtang; Zhang, Shikun; Poo, Mu-Ming; Gong, Neng

2017-03-21

Mirror self-recognition (MSR) is generally considered to be an intrinsic cognitive ability found only in humans and a few species of great apes. Rhesus monkeys do not spontaneously show MSR, but they have the ability to use a mirror as an instrument to find hidden objects. The mechanism underlying the transition from simple mirror use to MSR remains unclear. Here we show that rhesus monkeys could show MSR after learning precise visual-proprioceptive association for mirror images. We trained head-fixed monkeys on a chair in front of a mirror to touch with spatiotemporal precision a laser pointer light spot on an adjacent board that could only be seen in the mirror. After several weeks of training, when the same laser pointer light was projected to the monkey's face, a location not used in training, all three trained monkeys successfully touched the face area marked by the light spot in front of a mirror. All trained monkeys passed the standard face mark test for MSR both on the monkey chair and in their home cage. Importantly, distinct from untrained control monkeys, the trained monkeys showed typical mirror-induced self-directed behaviors in their home cage, such as using the mirror to explore normally unseen body parts. Thus, bodily self-consciousness may be a cognitive ability present in many more species than previously thought, and acquisition of precise visual-proprioceptive association for the images in the mirror is critical for revealing the MSR ability of the animal.
Design of Light-Weight High-Entropy Alloys

Directory of Open Access Journals (Sweden)

Rui Feng

2016-09-01

Full Text Available High-entropy alloys (HEAs are a new class of solid-solution alloys that have attracted worldwide attention for their outstanding properties. Owing to the demand from transportation and defense industries, light-weight HEAs have also garnered widespread interest from scientists for use as potential structural materials. Great efforts have been made to study the phase-formation rules of HEAs to accelerate and refine the discovery process. In this paper, many proposed solid-solution phase-formation rules are assessed, based on a series of known and newly-designed light-weight HEAs. The results indicate that these empirical rules work for most compositions but also fail for several alloys. Light-weight HEAs often involve the additions of Al and/or Ti in great amounts, resulting in large negative enthalpies for forming solid-solution phases and/or intermetallic compounds. Accordingly, these empirical rules need to be modified with the new experimental data. In contrast, CALPHAD (acronym of the calculation of phase diagrams method is demonstrated to be an effective approach to predict the phase formation in HEAs as a function of composition and temperature. Future perspectives on the design of light-weight HEAs are discussed in light of CALPHAD modeling and physical metallurgy principles.
Prototyping iridium coated mirrors for x-ray astronomy

Science.gov (United States)

Döhring, Thorsten; Probst, Anne-Catherine; Stollenwerk, Manfred; Emmerich, Florian; Stehlíková, Veronika; Inneman, Adolf

2017-05-01

X-ray astronomy uses space-based telescopes to overcome the disturbing absorption of the Earth's atmosphere. The telescope mirrors are operating at grazing incidence angles and are coated with thin metal films of high-Z materials to get sufficient reflectivity for the high-energy radiation to be observed. In addition the optical payload needs to be light-weighted for launcher mass constrains. Within the project JEUMICO, an acronym for "Joint European Mirror Competence", the Aschaffenburg University of Applied Sciences and the Czech Technical University in Prague started a collaboration to develop mirrors for X-ray telescopes. The X-ray telescopes currently developed within this Bavarian- Czech project are of Lobster eye type optical design. Corresponding mirror segments use substrates of flat silicon wafers which are coated with thin iridium films, as this material is promising high reflectivity in the X-ray range of interest. The deposition of the iridium films is based on a magnetron sputtering process. Sputtering with different parameters, especially by variation of the argon gas pressure, leads to iridium films with different properties. In addition to investigations of the uncoated mirror substrates the achieved surface roughness has been studied. Occasional delamination of the iridium films due to high stress levels is prevented by chromium sublayers. Thereby the sputtering parameters are optimized in the context of the expected reflectivity of the coated X-ray mirrors. In near future measurements of the assembled mirror modules optical performances are planned at an X-ray test facility.
A theory of frequency domain invariants: spherical harmonic identities for BRDF/lighting transfer and image consistency.

Science.gov (United States)

Mahajan, Dhruv; Ramamoorthi, Ravi; Curless, Brian

2008-02-01

This paper develops a theory of frequency domain invariants in computer vision. We derive novel identities using spherical harmonics, which are the angular frequency domain analog to common spatial domain invariants such as reflectance ratios. These invariants are derived from the spherical harmonic convolution framework for reflection from a curved surface. Our identities apply in a number of canonical cases, including single and multiple images of objects under the same and different lighting conditions. One important case we consider is two different glossy objects in two different lighting environments. For this case, we derive a novel identity, independent of the specific lighting configurations or BRDFs, that allows us to directly estimate the fourth image if the other three are available. The identity can also be used as an invariant to detecttampering in the images. While this paper is primarily theoretical, it has the potential to lay the mathematical foundations for two important practical applications. First, we can develop more general algorithms for inverse rendering problems, which can directly relight and change material properties by transferring the BRDF or lighting from another object or illumination. Second, we can check the consistency of an image, to detect tampering or image splicing.
An Hipotesis for PSA's solar furnace mirror improvement

Energy Technology Data Exchange (ETDEWEB)

La Padula, C.D.; Bartolini, C.; Beskin, G.; Cosentino, G.; Guarnieri, A.; Nanni, D.; Piccioni, A.

2002-07-01

The PSA's Solar Furnace capabilities can be greatly improved by replacing the present array mirrors with new ones. We will explain a rather cheap method (now under test) for the fabrication of the new mirrors, with a simple spherical figuring, and everyone identical to each other. Furthermore, we will describe the geometry the new array should have in order to avoid excessive aberrations due to the high obliquity of the rays with which most of the mirrors in the array have to deal with. (Author) 8 refs.
Method of increasing power within an optical cavity with long path lengths

Energy Technology Data Exchange (ETDEWEB)

Leen, John Brian; Bramall, Nathan E.

2018-03-13

A cavity-enhanced absorption spectroscopy instrument has an optical cavity with two or more cavity mirrors, one mirror of which having a hole or other aperture for injecting a light beam, and the same or another mirror of which being partially transmissive to allow exit of light to a detector. A spherical-spherical configuration with at least one astigmatic mirror or a spherical-cylindrical configuration where the spherical mirror could also be astigmatic prevents a reentrant condition wherein the injected beam would prematurely exit the cavity through the aperture. This combination substantially increases the number of passes of the injected beam through a sample volume for sensitive detection of chemical species even in less than ideal conditions including low power laser or LED sources, poor mirror reflectivity or detector noise at the wavelengths of interest, or cavity alignment issues such as vibration or temperature and pressure changes.
Support mechanism for a mirrored surface or other arrangement

Science.gov (United States)

Cutburth, Ronald W.

1987-01-01

An adjustment mechanism such as a three point spherical mount for adjustably supporting a planer mirror or other type of arrangement relative to a plane defined by a given pair of intersecting perpendicular axes is disclosed herein. This mechanism includes first means for fixedly supporting the mirror or other arrangement such that the latter is positionable within the plane defined by the given pair of intersecting perpendicular axes. This latter means and the mirror or other such arrangement are supported by second means for limited movement back and forth about either of the intersecting axes. Moreover, this second means supports the first means and the mirror or other arrangement such that the latter is not movable in any other way whereby the point on the mirror or other arrangement coinciding with the intersection of the given axes does not move or float, thereby making the ability to adjust the mirror or other such arrangement more precise and accurate.
X-ray telescope mirrors made of slumped glass sheets

Science.gov (United States)

Winter, A.; Breunig, E.; Friedrich, P.; Proserpio, L.

2017-11-01

For several decades, the field of X-ray astronomy has been playing a major role in understanding the processes in our universe. From binary stars and black holes up to galaxy clusters and dark matter, high energetic events have been observed and analysed using powerful X-ray telescopes like e.g. Rosat, Chandra, and XMM-Newton [1,2,3], giving us detailed and unprecedented views of the high-energy universe. In November 2013, the theme of "The Hot and Energetic Universe" was rated as of highest importance for future exploration and in June 2014 the ATHENA Advanced Telescope for High Energy Astrophysics was selected by ESA for the second large science mission (L2) in the ESA Cosmic Vision program, with launch foreseen in 2028 [4]. By combining a large X-ray telescope with state-of-the-art scientific instruments, ATHENA will address key questions in astrophysics, including: How and why does ordinary matter assemble into the galaxies and galactic clusters that we see today? How do black holes grow and influence their surroundings? In order to answer these questions, ATHENA needs a powerful mirror system which exceed the capabilities of current missions, especially in terms of collecting area. However, current technologies have reached the mass limits of the launching rocket, creating the need for more light-weight mirror systems in order to enhance the effective area without increasing the telescope mass. Hence new mirror technologies are being developed which aim for low-weight systems with large collecting areas. Light material like glass can be used, which are shaped to form an X-ray reflecting system via the method of thermal glass slumping.
A generalized construction of mirror manifolds

International Nuclear Information System (INIS)

Berglund, P.; Huebsch, T.

1993-01-01

We generalize the known method for explicit construction of mirror pairs of (2,2)-superconformal field theories, using the formalism of Landau-Ginzburg orbifolds. Geometrically, these theories are realized as Calabi-Yau hypersurfaces in weighted projective spaces. This generalization makes it possible to construct the mirror partners of many manifolds for which the mirror was not previously known. (orig.)
Weld evaluation on spherical pressure vessels using holographic interferometry

International Nuclear Information System (INIS)

Boyd, D.M.; Wilcox, W.W.

1980-01-01

Waist welds on spherical experimental pressure vessels have been evaluated under pressure using holographic interferometry. A coincident viewing and illumination optical configuration coupled with a parabolic mirror was used so that the entire weld region could be examined with a single hologram. Positioning the pressure vessel at the focal point of the parabolic mirror provides a relatively undistorted 360 degree view of the waist weld. Double exposure and real time holography were used to obtain displacement information on the weld region. Results are compared with radiographic and ultrasonic inspections
Near-field flat focusing mirrors

Science.gov (United States)

Cheng, Yu-Chieh; Staliunas, Kestutis

2018-03-01

This article reviews recent progress towards the design of near-field flat focusing mirrors, focusing/imaging light patterns in reflection. An important feature of such flat focusing mirrors is their transverse invariance, as they do not possess any optical axis. We start with a review of the physical background to the different focusing mechanisms of near- and far-field focusing. These near-field focusing devices like flat lenses and the reviewed near-field focusing mirrors can implement planar focusing devices without any optical axis. In contrast, various types of far-field planar focusing devices, such as high-contrast gratings and metasurfaces, unavoidably break the transverse invariance due to their radially symmetrical structures. The particular realizations of near-field flat focusing mirrors including Bragg-like dielectric mirrors and dielectric subwavelength gratings are the main subjects of the review. The first flat focusing mirror was demonstrated with a chirped mirror and was shown to manage an angular dispersion for beam focusing, similar to the management of chromatic dispersion for pulse compression. Furthermore, the reviewed optimized chirped mirror demonstrated a long near-field focal length, hardly achieved by a flat lens or a planar hyperlens. Two more different configurations of dielectric subwavelength gratings that focus a light beam at normal or oblique incidence are also reviewed. We also summarize and compare focusing performance, limitations, and future perspectives between the reviewed flat focusing mirrors and other planar focusing devices including a flat lens with a negative-index material, a planar hyperlens, a high-contrast grating, and a metasurface.
Dynamic coherent backscattering mirror

Energy Technology Data Exchange (ETDEWEB)

Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)

2016-02-15

The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.
The objective lens of the electron microscope with correction of spherical and axial chromatic aberrations.

Science.gov (United States)

Bimurzaev, S B; Aldiyarov, N U; Yakushev, E M

2017-10-01

The paper describes the principle of operation of a relatively simple aberration corrector for the transmission electron microscope objective lens. The electron-optical system of the aberration corrector consists of the two main elements: an electrostatic mirror with rotational symmetry and a magnetic deflector formed by the round-shaped magnetic poles. The corrector operation is demonstrated by calculations on the example of correction of basic aberrations of the well-known objective lens with a bell-shaped distribution of the axial magnetic field. Two of the simplest versions of the corrector are considered: a corrector with a two-electrode electrostatic mirror and a corrector with a three-electrode electrostatic mirror. It is shown that using the two-electrode mirror one can eliminate either spherical or chromatic aberration of the objective lens, without changing the value of its linear magnification. Using a three-electrode mirror, it is possible to eliminate spherical and chromatic aberrations of the objective lens simultaneously, which is especially important in designing electron microscopes with extremely high resolution. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Light variations of a spherical star with two hot precessing spots

International Nuclear Information System (INIS)

Kyurkchieva, D.P.; Shkodrov, V.G.

1984-01-01

In one of the models of SS443, suggested by Lipunov and Shakura (1982), the second component of the double stellar system is considered a star with two hot spots on the surface. Since the gas jets forming the spots are precessing, the hot spots on the visible disk will do likewise. In this paper, the light variations of a spherical star with two precessing hot spots are analyzed under the following restrictive conditions: (I) the inclination of the precession axis toward the line of sight is i=π/2; (II) the visible disk of the spherical star is considered uniformly illuminated, i.e. the effect of the variation in intensity from the disk center to the limb is neglected. The time variations in the projection area of the precessing spots on the visible stellar disk are investigated. In the studies to follow, the same effect will be analyzed assuming: (1) inot=π/2; (2) the variation in intensity is estimated from center to the stellar boundary; (3) a case of ellipsoidal stars; (4) this effect added to the effect of darkening due to orbital movement in a double stellar system
Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

Science.gov (United States)

Dohi, Hideto; Kruit, Pieter

2018-06-01

Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed
Light Weight Deflectometer (LWD)

OpenAIRE

Siddiki, Nayyar Zia

2012-01-01

Light weight deflectometer (LWD) has been widely used for quality assurance in road construction, in particular compaction of both chemically treated subgrade soil and aggregate subbase. However, it has been recognized that LWD measurements vary with many factors. Based on LWD tests in actual road construction, this presentation provides updated information on the LWD deflection measurements for both chemically treated subgrade soil and aggregate subbase.
Determination of tolerances of mirror displacement and radiator gas impurity for the CBM RICH detector

Energy Technology Data Exchange (ETDEWEB)

Adamczewski-Musch, J. [GSI Darmstadt (Germany); Becker, K.-H. [University Wuppertal (Germany); Belogurov, S. [ITEP Moscow (Russian Federation); Boldyreva, N. [PNPI Gatchina (Russian Federation); Chernogorov, A. [ITEP Moscow (Russian Federation); Deveaux, C. [University Gießen (Germany); Dobyrn, V. [PNPI Gatchina (Russian Federation); Dürr, M. [University Gießen (Germany); Eom, J. [Pusan National University (Korea, Republic of); Eschke, J. [GSI Darmstadt (Germany); Höhne, C. [University Gießen (Germany); Kampert, K.-H. [University Wuppertal (Germany); Kleipa, V. [GSI Darmstadt (Germany); Kochenda, L. [PNPI Gatchina (Russian Federation); Kolb, B. [GSI Darmstadt (Germany); Kopfer, J. [University Wuppertal (Germany); Kravtsov, P. [PNPI Gatchina (Russian Federation); Lebedev, S.; Lebedeva, E. [University Gießen (Germany); Leonova, E. [PNPI Gatchina (Russian Federation); and others

2014-12-01

The CBM experiment at the future FAIR facility will explore nuclear matter at high net-baryon densities. One of the key observables is di-leptons as they penetrate the created matter without further strong interactions. A gaseous RICH detector in a standard projective geometry using spherical mirrors is one of two detector elements for the required electron identification. The mirror system consists of about 72 trapezoidal mirror tiles. Any misalignment between the tiles relative to the nominal common spherical surface leads to reduction of the reconstruction efficiency of Cherenkov rings and deterioration of their resolution. To determine tolerances in mirror misalignment extensive simulation and measurement studies were carried out. Pure CO{sub 2} will be used as radiator gas. Gas contamination, mainly moisture and Oxygen, reduces the number of detected photons per ring and worsens the quality of reconstructed Cherenkov rings. Therefore a study was carried out to determine tolerances in radiator gas contamination. - Highlights: • Mirror misalignment leads to ring deformation in a RICH detector. • Radiator contamination leads to resolution deterioration of fitted rings. • To determine tolerances measurements and simulations were carried out. • Mirror displacements of up to 0.32 mm at any mirror side can be tolerated. • Oxygen (moisture) contamination of up to 1% (0.0011%) can be safely tolerated.
Mirrors for synchrotron-radiation beamlines

International Nuclear Information System (INIS)

Howells, M.R.

1993-09-01

The authors consider the role of mirrors in synchrotron-radiation beamlines and discuss the optical considerations involved in their design. They discuss toroidal, spherical, elliptical, and paraboloidal mirrors in detail with particular attention to their aberration properties. They give a treatment of the sine condition and describe its role in correcting the coma of axisymmetric systems. They show in detail how coma is inevitable in single-reflection, grazing-incidence systems but correctable in two-reflection systems such as those of the Wolter type. In an appendix, they give the theory of point aberrations of reflectors of a general shape and discuss the question of correct naming of aberrations. In particular, a strict definition of coma is required if attempts at correction are to be based on the sine condition

Fabrication Process Development for Light Deformable Mirrors

Data.gov (United States)

National Aeronautics and Space Administration — The project objective is to develop robust, reproductibble fabrication processes to realize functional deformable membrane mirrors (DM) for a space mission in which...
Mechanical Design of the HER Synchrotron Light Monitor Primary Mirror

Energy Technology Data Exchange (ETDEWEB)

Daly, Edward F.; /SLAC; Fisher, Alan S.; Kurita, Nadine R.; Langton, J.; /SLAC

2011-09-14

This paper describes the mechanical design of the primary mirror that images the visible portion of the synchrotron radiation (SR) extracted from the High Energy Ring (HER) of the PEP-II B-Factory. During off-axis operation, the water-cooled GlidCop mirror is subjected to a heat flux in excess of 2000 W/cm2. When on-axis imaging occurs, the heat flux due to scattered SR, resistive wall losses and Higher-Order-Mode (HOM) heating is estimated at 1 W/cm2. The imaging surface is plated with Electroless Nickel to improve its optical characteristics. The design requirements for the primary mirror are listed and discussed. Calculated mechanical distortions and stresses experienced by the mirror during on-axis and off-axis operation will be presented.
Dynamic deformation theory of spherical and deformed light and heavy nuclei with A = 12-240

International Nuclear Information System (INIS)

Kumar, Krishna.

1979-01-01

Deformation dependent wave functions are calculated for different types of even-even nuclei (spherical, transitional, deformed; light, medium, heavy) without any fitting parameters. These wave functions are employed for the energies, B(E2)'s, quadrupole and magnetic moments of selected nuclei with A = 12-240 (with special emphasis on 56 Fe, 154 Gd), and for neutron cross sections of 148 Sm, 152 Sm
The importance of being light: aerodynamic forces and weight in ski jumping.

Science.gov (United States)

Schmölzer, B; Müller, W

2002-08-01

Many contemporary world class ski jumpers are alarmingly underweight and several cases of anorexia nervosa have come to light. Athletes strive for low body weight because it gives them a major competitive advantage. In order to stop this hazardous development, changes to the regulations are being discussed, and the International Ski Federation and the International Olympic Committee wish to be proactive in safe guarding the interest of the athletes and their health. This study of ski jumping uses field studies conducted during World Cup competitions, large-scale wind tunnel measurements with 1:1 models of ski jumpers in current equipment and highly accurate computer simulations of the flight phase that include the effects due to the athlete's position changes. Particular attention has been directed to the design of a reference jump that mirrors current flight style and equipment regulations (2001), and to the investigation of effects associated with variation in body mass, air density, and wind gusts during the simulated flight. The detailed analysis of the physics of ski jumping described here can be used for the investigation of all initial value and parameter variations that determine the flight path of a ski jumper and will form a reliable basis for setting regulations that will make it less attractive or even disadvantageous for the athlete to be extremely light.
Application of the weighted total field-scattering field technique to 3D-PSTD light scattering model

Science.gov (United States)

Hu, Shuai; Gao, Taichang; Liu, Lei; Li, Hao; Chen, Ming; Yang, Bo

2018-04-01

PSTD (Pseudo Spectral Time Domain) is an excellent model for the light scattering simulation of nonspherical aerosol particles. However, due to the particularity of its discretization form of the Maxwell's equations, the traditional Total Field/Scattering Field (TF/SF) technique for FDTD (Finite Differential Time Domain) is not applicable to PSTD, and the time-consuming pure scattering field technique is mainly applied to introduce the incident wave. To this end, the weighted TF/SF technique proposed by X. Gao is generalized and applied to the 3D-PSTD scattering model. Using this technique, the incident light can be effectively introduced by modifying the electromagnetic components in an inserted connecting region between the total field and the scattering field region with incident terms, where the incident terms are obtained by weighting the incident field by a window function. To optimally determine the thickness of connection region and the window function type for PSTD calculations, their influence on the modeling accuracy is firstly analyzed. To further verify the effectiveness and advantages of the weighted TF/SF technique, the improved PSTD model is validated against the PSTD model equipped with pure scattering field technique in both calculation accuracy and efficiency. The results show that, the performance of PSTD seems to be not sensitive to variation of window functions. The number of the connection layer required decreases with the increasing of spatial resolution, where for spatial resolution of 24 grids per wavelength, a 6-layer region is thick enough. The scattering phase matrices and integral scattering parameters obtained by the improved PSTD show an excellent consistency with those well-tested models for spherical and nonspherical particles, illustrating that the weighted TF/SF technique can introduce the incident precisely. The weighted TF/SF technique shows higher computational efficiency than pure scattering technique.
Phase measuring deflectometry. An improved setup for measuring CTA mirror facets

Energy Technology Data Exchange (ETDEWEB)

Specovius, Andreas; Eldik, Christopher van; Woernlein, Andre; Ziegler, Alexander [Erlangen Centre for Astroparticle Physics (ECAP) (Germany)

2016-07-01

The future Cherenkov Telescope Array (CTA) will consist of up to 100 single telescopes with a total reflecting surface of ∝10.000 m{sup 2} made of numerous mirror facets. Characterizing the surface properties of these facets is quite challenging concerning time and logistics. An efficient way to reliably reconstruct the surface of specular free-forms is Phase Measuring Deflectometry (PMD). PMD is routinely used to characterize the focal distance and point spread function of spherical CTA prototype mirrors. To address the possibility to measure the surface properties of aspherical mirrors, a new PMD setup has recently been built. First experience with this setup is reported.
Active Mirror Predictive and Requirements Verification Software (AMP-ReVS)

Science.gov (United States)

Basinger, Scott A.

2012-01-01

This software is designed to predict large active mirror performance at various stages in the fabrication lifecycle of the mirror. It was developed for 1-meter class powered mirrors for astronomical purposes, but is extensible to other geometries. The package accepts finite element model (FEM) inputs and laboratory measured data for large optical-quality mirrors with active figure control. It computes phenomenological contributions to the surface figure error using several built-in optimization techniques. These phenomena include stresses induced in the mirror by the manufacturing process and the support structure, the test procedure, high spatial frequency errors introduced by the polishing process, and other process-dependent deleterious effects due to light-weighting of the mirror. Then, depending on the maturity of the mirror, it either predicts the best surface figure error that the mirror will attain, or it verifies that the requirements for the error sources have been met once the best surface figure error has been measured. The unique feature of this software is that it ties together physical phenomenology with wavefront sensing and control techniques and various optimization methods including convex optimization, Kalman filtering, and quadratic programming to both generate predictive models and to do requirements verification. This software combines three distinct disciplines: wavefront control, predictive models based on FEM, and requirements verification using measured data in a robust, reusable code that is applicable to any large optics for ground and space telescopes. The software also includes state-of-the-art wavefront control algorithms that allow closed-loop performance to be computed. It allows for quantitative trade studies to be performed for optical systems engineering, including computing the best surface figure error under various testing and operating conditions. After the mirror manufacturing process and testing have been completed, the
On horizonless temperature with an accelerating mirror

Energy Technology Data Exchange (ETDEWEB)

Good, Michael R.R.; Yelshibekov, Khalykbek [Department of Physics, School of Science and Technology, Nazarbayev University,53 Kabanbay Batyr Ave., Astana, 010000 Republic of (Kazakhstan); Ong, Yen Chin [Center for Astronomy and Astrophysics, Department of Physics and Astronomy,Shanghai Jiao Tong University, Shanghai, 200240 (China); Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, Stockholm, SE-106 91 (Sweden)

2017-03-03

A new solution of a unitary moving mirror is found to produce finite energy and emit thermal radiation despite the absence of an acceleration horizon. In the limit that the mirror approaches the speed of light, the model corresponds to a black hole formed from the collapse of a null shell. For speeds less than light, the black hole correspondence, if it exists, is that of a remnant.
Development of highly polished, grazing incidence mirrors for synchrotron radiation beam lines at SSRL

Energy Technology Data Exchange (ETDEWEB)

Tirsell, K.G.; Berglin, E.J.; Fuchs, B.A.; Holdener, F.R.; Humpal, H.H.; Karpenko, V.P.; Kulkarni, S.; Fantone, S.D.

1987-08-01

New platinum-coated grazing incidence mirrors with low surface roughnesses have been developed to focus bending magnet radiation from the SSRL/SLAC SPEAR storage ring on the entrance slits of two Beam Line VIII grating monochromators. The first mirror in the toroidal grating monochromator (TGM) branch is a cooled SiC cylinder capable of absorbing synchrotron radiation power levels of up to 260 watts without excessive distortion. This mirror deflects the beam vertically through a 12/degree/ angle and focuses it sagitally on the TGM entrance slit plane. The second TGM optical element is a fused-silica spherical mirror with a large radius of curvature that deflects the beam vertically through an additional 12/degree/ and focuses it tangentially with 3/1 demagnification. The first mirror in our spherical grating branch is a 5/degree/-vertically deflecting, cooled SiC toroid designed to focus tangentially on the monochromator entrance slits and sagitally in the exit slits. A 4/degree/-deflecting fused silica mirror is used after the exit sites in each beam line to refocus on to the sample. For this application a thin cylinder is bent to approximate an ellipsoid. The mirrors are now installed at SSRL and performance measurements are planned. Qualitatively the focus of the TGM optics at the entrance slit plane appears very good. In this paper we discuss considerations leading to the choice of SiC for each of the two first mirrors. We present highlights of the development of these mirrors with some emphasis on SiC polishing techniques. In addition, the specialized metrology developed to produce the more difficult figure of the toroid will be described. Measured surface roughness and figure results will be presented. 19 refs., 11 figs.
Development of highly polished, grazing incidence mirrors for synchrotron radiation beam lines at SSRL

International Nuclear Information System (INIS)

Tirsell, K.G.; Berglin, E.J.; Fuchs, B.A.; Holdener, F.R.; Humpal, H.H.; Karpenko, V.P.; Kulkarni, S.; Fantone, S.D.

1987-08-01

New platinum-coated grazing incidence mirrors with low surface roughnesses have been developed to focus bending magnet radiation from the SSRL/SLAC SPEAR storage ring on the entrance slits of two Beam Line VIII grating monochromators. The first mirror in the toroidal grating monochromator (TGM) branch is a cooled SiC cylinder capable of absorbing synchrotron radiation power levels of up to 260 watts without excessive distortion. This mirror deflects the beam vertically through a 12/degree/ angle and focuses it sagitally on the TGM entrance slit plane. The second TGM optical element is a fused-silica spherical mirror with a large radius of curvature that deflects the beam vertically through an additional 12/degree/ and focuses it tangentially with 3/1 demagnification. The first mirror in our spherical grating branch is a 5/degree/-vertically deflecting, cooled SiC toroid designed to focus tangentially on the monochromator entrance slits and sagitally in the exit slits. A 4/degree/-deflecting fused silica mirror is used after the exit sites in each beam line to refocus on to the sample. For this application a thin cylinder is bent to approximate an ellipsoid. The mirrors are now installed at SSRL and performance measurements are planned. Qualitatively the focus of the TGM optics at the entrance slit plane appears very good. In this paper we discuss considerations leading to the choice of SiC for each of the two first mirrors. We present highlights of the development of these mirrors with some emphasis on SiC polishing techniques. In addition, the specialized metrology developed to produce the more difficult figure of the toroid will be described. Measured surface roughness and figure results will be presented. 19 refs., 11 figs
21 CFR 886.1500 - Headband mirror.

Science.gov (United States)

2010-04-01

... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1500 Headband mirror. (a) Identification. A headband mirror is a device intended to be strapped to the head of the user to reflect light for use in examination of the eye. (b) Classification. Class I (general controls). The device is exempt from the...
Manufacturing aspheric mirrors made of zero thermal expansion cordierite ceramics using Magnetorheological Finishing (MRF)

Science.gov (United States)

Sugawara, Jun; Maloney, Chris

2016-07-01

NEXCERATM cordierite ceramics, which have ultra-low thermal expansion properties, are perfect candidate materials to be used for light-weight satellite mirrors that are used for geostationary earth observation and for mirrors used in ground-based astronomical metrology. To manufacture the high precision aspheric shapes required, the deterministic aspherization and figure correction capabilities of Magnetorheological Finishing (MRF) are tested. First, a material compatibility test is performed to determine the best method for achieving the lowest surface roughness of RMS 0.8nm on plano surfaces made of NEXCERATM ceramics. Secondly, we will use MRF to perform high precision figure correction and to induce a hyperbolic shape into a conventionally polished 100mm diameter sphere.
Vacuum-Flex Figuring of Primary Telescope Mirrors

Science.gov (United States)

Albin, E. F. M.

2004-12-01

In the current investigation, details on the construction and performance of a vacuum-flexed (i.e., figured) 51 cm (20-inch) mirror, with a fast f/4 focal ratio, are presented. A vacuum has the chief advantage of being able to pull with a uniform or isotropic stress across a large surface area, which will naturally form a parabolic surface. The essence of the idea is to grind and polish a spherical mirror and then warp or flex it into a near perfect paraboloid, thus avoiding tedious figuring altogether. To date, telescope makers around the globe have experimented with small flexed mirrors with considerable success. In these instances, mirrors have been flexed by exerting tension on a bolt or sponge-pad adhered to the back of the mirror. The prototype mirror consists of two 51 cm disks of plate glass -- each slumped to an f/4 focal ratio. The front-plate (19 mm in thickness) is separated from the back-plate (13 mm in thickness) back a flexible 9.5 mm air filled gasket. Although the rubber gasket makes a fairly good vacuum seal, silicon cement was placed about the outer edge in order to produce a perfectly tight seal. A vacuum of 8 kPa on the back of the mirror resulted in approximately 164 kilograms of negative pressure, which is required to flex the mirror into the required paraboloid. Ronchi test show a nice smooth paraboloid free from astigmatism while foucault zonal measurements display a figure better than 1/20 wave. Preliminary star testing show promising results as well. Vacuum-flexed mirrors may have benefits for both amateur and professional telescope makers alike. A US patent is pending on the aforementioned design.
Bright Light for Weight Loss: Results of a Controlled Crossover Trial

Directory of Open Access Journals (Sweden)

Konstantin V. Danilenko

2013-02-01

Full Text Available Objective: To investigate whether bright light treatment can reduce body mass in overweight subjects irrespective of their seasonal (= light dependence. Methods: A crossover, placebo-controlled, randomized clinical trial was performed between November and April in Novosibirsk, Russia (55° N. The trial comprised a 3-week in-home session of morning bright light treatment using a device of light-emitting diodes and a 3-week placebo session by means of a deactivated ion generator, separated by an off-protocol period of at least 23 days. The number of placebo and light sessions was matched with respect to season. Data were obtained from 34 overweight women, aged 20-54 years, 10 were seasonal-dependent according to the Seasonal Pattern Assessment Questionnaire. Weekly measures included body weight, percentage body fat by bioimpedancemetry, and subjective scores (appetite, mood, energy levels. Results: Motivation and expectation towards weight loss were similar for the two intervention sessions. With light, compared to the placebo session, weight did not reduce significantly, but percentage fat, fat mass, and appetite were significantly lower (average fat reduction 0.35 kg. The latter two results remained significant after excluding seasonal-dependent subjects from the analysis. Irrespective of the type of intervention, seasonal-dependent subjects had greater weight and fat mass changes during treatment (decline p 0.036 or between sessions (regain p 0.003. Photoperiod (p = 0.0041, air temperature to a lesser extent (p = 0.012, but not sunshine (p = 0.29 was associated with the weight change (greater weight reduction if the second session was in spring. Conclusion: Morning bright light treatment reduces body fat and appetite in overweight women and may be included in weight control programs.
Lessons Learned During Cryogenic Optical Testing of the Advanced Mirror System Demonstrators (AMSDs)

Science.gov (United States)

Hadaway, James; Reardon, Patrick; Geary, Joseph; Robinson, Brian; Stahl, Philip; Eng, Ron; Kegley, Jeff

2004-01-01

Optical testing in a cryogenic environment presents a host of challenges above and beyond those encountered during room temperature testing. The Advanced Mirror System Demonstrators (AMSDs) are 1.4 m diameter, ultra light-weight (mA2), off-axis parabolic segments. They are required to have 250 nm PV & 50 nm RMS surface figure error or less at 35 K. An optical testing system, consisting of an Instantaneous Phase Interferometer (PI), a diffractive null corrector (DNC), and an Absolute Distance Meter (ADM), was used to measure the surface figure & radius-of-curvature of these mirrors at the operational temperature within the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The Ah4SD program was designed to improve the technology related to the design, fabrication, & testing of such mirrors in support of NASA s James Webb Space Telescope (JWST). This paper will describe the lessons learned during preparation & cryogenic testing of the AMSDs.
HOKES/POKES : Light-weight resource sharing

NARCIS (Netherlands)

Bos, Herbert; Samwel, Bart

2003-01-01

In this paper, we explain mechanisms for providing embedded network processors and other low-level programming environments with light-weight support for safe resource sharing. The solution consists of a host part, known as HOKES, and a network processor part, known as POKES. As common operating
Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

Science.gov (United States)

Mohapatra, Rabindra N.; Nussinov, Shmuel

2018-01-01

The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n -n‧ mixing parameter δ and n -n‧ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ ≤ 2 ×10-27 GeV and Δ ≤10-24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.
InPhoCUS (Inflated Photovoltaic Ultra-light Mirror Concentrators): First Results Of The Project And Future Perspectives

Science.gov (United States)

Pravettoni, Mauro; Barbato, Maurizio; Cooper, Thomas; Pedretti, Andrea; Ambrosetti, Gianluca; Steinfeld, Aldo

2011-12-01

InPhoCUS (Inflated PhotovoltaiC Ultra-light mirror concentratorS) is a concentrating photovoltaic (CPV) project funded by the Swiss Confederation's Innovation Promotion Agency (CTI) and developed by Airlight Energy Holding SA, the University of Applied Sciences and Arts of Southern Switzerland and the Swiss Federal Institute of Technology. The proposed novel concentrating system has already been patented for concentrated solar power applications: it is made by unconventional pneumatic multilayer polymeric mirrors, has an innovative fibre-reinforced concrete structure and an original tilting mechanism to track the sun. The innovative CPV solar collector is profitable for electric power plants both for the sun-belt region and in the Mediterranean. In this paper the authors present the novel CPV system and preliminary results on cost analysis, optical design and thermal modelling.
Entangling movable mirrors in a double cavity system

DEFF Research Database (Denmark)

Pinard, Michel; Dantan, Aurelien Romain; Vitali, David

2005-01-01

We propose a double-cavity set-up capable of generating a stationary entangled state of two movable mirrors at cryogenic temperatures. The scheme is based on the optimal transfer of squeezing of input optical fields to mechanical vibrational modes of the mirrors, realized by the radiation pressure...... of the intracavity light. We show that the presence of macroscopic entanglement can be demonstrated by an appropriate readout of the output light of the two cavities....
Hi-speed compact deformable mirror: status, applications, and perspectives

Science.gov (United States)

Rooms, F.; Camet, S.; Curis, J.-F.

2010-02-01

Membrane deformable mirrors based on magnetic actuators have been known for years. State-of-the-art deformable mirrors usually have large strokes but low bandwidth. Furthermore, this bandwidth decreases with the diameter. In this paper, we present the results of a new actuator principle based on magnetic forces allowing high bandwidth (up to a few kHz), very large stroke (>30μm) with a record pitch of 1.5mm. The benefits of this technology will be presented for three applications: astronomy, vision science and microscopy. The parameters of the mirrors have been tuned such that the inter-actuator stroke of the deformable (more than 2.0μm) in order to fit the atmosphere turbulence characteristics. In vision science, efforts have been made to correct both simultaneously the low and high order aberrations (more than 45μm of wavefront correction on astigmatism and focus). Finally, we will demonstrate how we have developed a deformable mirror able to correct spherical aberrations (microscopy). The last part of the article is devoted to give some perspectives about this technology.

A novel automotive headlight system based on digital micro-mirror devices and diffractive optical elements

Science.gov (United States)

Su, Ping; Song, Yuming; Ma, Jianshe

2018-01-01

The DMD (Digital Micro-mirror Device) has the advantages of high refresh rate and high diffraction efficiency, and these make it become an ideal loader of multiple modes illumination. DOEs (Diffractive Optical Element) have the advantages of high degree of freedom, light weight, easy to copy, low cost etc., and can be used to reduce the weight, complexity, cost of optical system. A novel automotive headlamp system using DMD as the light distribution element and a DOE as the light field modulation device is proposed in this paper. The pure phase DOE is obtained by the GS algorithm using Rayleigh-Sommerfeld diffraction integral model. Based on the standard automotive headlamp light intensity distribution in the target plane, the amplitude distribution of DMD is obtained by numerical simulation, and the grayscale diagram loaded on the DMD can be obtained accordingly. Finally, according to simulation result, the light intensity distribution in the target plane is proportional to the national standard, hence verifies the validity of the novel system. The novel illumination system proposed in this paper provides a reliable hardware platform for the intelligent headlamps.
Computation of higher spherical harmonics moments of the angular flux for neutron transport problems in spherical geometry

International Nuclear Information System (INIS)

Sahni, D.C.; Sharma, A.

2000-01-01

The integral form of one-speed, spherically symmetric neutron transport equation with isotropic scattering is considered. Two standard problems are solved using normal mode expansion technique. The expansion coefficients are obtained by solving their singular integral equations. It is shown that these expansion coefficients provide a representation of all spherical harmonics moments of the angular flux as a superposition of Bessel functions. It is seen that large errors occur in the computation of higher moments unless we take certain precautions. The reasons for this phenomenon are explained. They throw some light on the failure of spherical harmonics method in treating spherical geometry problems as observed by Aronsson
Literature Review of Shear Performance of Light-weight Steel Framing Wall Panels

Science.gov (United States)

Zhang, Zhuangnan; Liu, Shen; Liu, Hong

2018-03-01

In this paper, a comprehensive review of light-weight steel framing wall panels was carried out. The structure and force characteristics of light-weight steel framing wall panels were introduced. The testing and theoretical research results on the shear behaviour of light-weight steel framing wall panels were summarized in the domestic and foreign. And combined with the existing standards in China, the author's views and ideas are put forward to the problems in the research field of this kind of structural system.
Genetic mapping and QTL analysis for body weight in Jian carp ( Cyprinus carpio var. Jian) compared with mirror carp ( Cyprinus carpio L.)

Science.gov (United States)

Gu, Ying; Lu, Cuiyun; Zhang, Xiaofeng; Li, Chao; Yu, Juhua; Sun, Xiaowen

2015-05-01

We report the genetic linkage map of Jian carp ( Cyprinus carpio var. Jian). An F1 population comprising 94 Jian carp individuals was mapped using 254 microsatellite markers. The genetic map spanned 1 381.592 cM and comprised 44 linkage groups, with an average marker distance of 6.58 cM. We identified eight quantitative trait loci (QTLs) for body weight (BW) in seven linkage groups, explaining 12.6% to 17.3% of the phenotypic variance. Comparative mapping was performed between Jian carp and mirror carp ( Cyprinus carpio L.), which both have 50 chromosomes. One hundred and ninety-eight Jian carp marker loci were found in common with the mirror carp map, with 186 (93.94%) showing synteny. All 44 Jian carp linkage groups could be one-to-one aligned to the 44 mirror carp linkage groups, mostly sharing two or more common loci. Three QTLs for BW in Jian carp were conserved in mirror carp. QTL comparison suggested that the QTL confidence interval in mirror carp was more precise than the homologous interval in Jian carp, which was contained within the QTL interval in Jian carp. The syntenic relationship and consensus QTLs between the two varieties provide a foundation for genomic research and genetic breeding in common carp.
Differential interferometer for measurement of displacement of laser resonator mirrors

Science.gov (United States)

Macúchová, Karolina; Němcová, Šárka; Hošek, Jan

2015-01-01

This paper covers a description and a technique of a possible optical method of mode locking within a laser resonator. The measurement system is a part of instrumentation of laser-based experiment OSQAR at CERN. The OSQAR experiment aims at search of axions, axion-like particles and measuring of ultra-fine vacuum magnetic birefringence. It uses a laser resonator to enhance the coupling constant of hypothetical photon-to-axion conversion. The developed locking-in technique is based on differential interferometry. Signal obtained from the measurement provide crucial information for adaptive control of the locking-in of the resonator in real time. In this paper we propose several optical setups used for measurement and analysis of mutual position of the resonator mirrors. We have set up a differential interferometer under our laboratory conditions. We have done measurements with hemi-spherical cavity resonator detuned with piezo crystals. The measurement was set up in a single plane. Laser light was directed through half-wave retarder to a polarizing beam splitter and then converted to circular polarization by lambda/4 plates. After reflection at the mirrors, the beam is recombined in a beam splitter, sent to analyser and non-polarizing beam splitter and then inspected by two detectors with mutually perpendicular polarizers. The 90 degrees phase shift between the two arms allows precise analysis of a mutual distance change of the mirrors. Because our setup was sufficiently stable, we were able to measure the piezo constant and piezo hysteresis. The final goal is to adapt the first prototype to 23 m resonator and measure the displacement in two planes.
Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

Directory of Open Access Journals (Sweden)

Rabindra N. Mohapatra

2018-01-01

Full Text Available The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n−n′ mixing parameter δ and n−n′ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ≤2×10−27 GeV and Δ≤10−24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.
Performance of lightweight large C/SiC mirror

Science.gov (United States)

Yui, Yukari Y.; Goto, Ken; Kaneda, Hidehiro; Katayama, Haruyoshi; Kotani, Masaki; Miyamoto, Masashi; Naitoh, Masataka; Nakagawa, Takao; Saruwatari, Hideki; Suganuma, Masahiro; Sugita, Hiroyuki; Tange, Yoshio; Utsunomiya, Shin; Yamamoto, Yasuji; Yamawaki, Toshihiko

2017-11-01

Very lightweight mirror will be required in the near future for both astronomical and earth science/observation missions. Silicon carbide is becoming one of the major materials applied especially to large and/or light space-borne optics, such as Herschel, GAIA, and SPICA. On the other hand, the technology of highly accurate optical measurement of large telescopes, especially in visible wavelength or cryogenic circumstances is also indispensable to realize such space-borne telescopes and hence the successful missions. We have manufactured a very lightweight Φ=800mm mirror made of carbon reinforced silicon carbide composite that can be used to evaluate the homogeneity of the mirror substrate and to master and establish the ground testing method and techniques by assembling it as the primary mirror into an optical system. All other parts of the optics model are also made of the same material as the primary mirror. The composite material was assumed to be homogeneous from the mechanical tests of samples cut out from the various areas of the 800mm mirror green-body and the cryogenic optical measurement of the mirror surface deformation of a 160mm sample mirror that is also made from the same green-body as the 800mm mirror. The circumstance and condition of the optical testing facility has been confirmed to be capable for the highly precise optical measurements of large optical systems of horizontal light axis configuration. Stitching measurement method and the algorithm for analysis of the measurement is also under study.
A Light-Weight Instrumentation System Design

International Nuclear Information System (INIS)

Kidner, Ronald

1999-01-01

To meet challenging constraints on telemetry system weight and volume, a custom Light-Weight Instrumentation System was developed to collect vehicle environment and dynamics on a short-duration exo-atmospheric flight test vehicle. The total telemetry system, including electronics, sensors, batteries, and a 1 watt transmitter weighs about 1 kg. Over 80 channels of measurement, housekeeping, and telemetry system diagnostic data are transmitted at 128 kbps. The microcontroller-based design uses the automotive industry standard Controller Area Network to interface with and support in-flight control fimctions. Operational parameters are downloaded via a standard asynchronous serial communications intefiace. The basic design philosophy and functionality is described here
High coupling efficiency of foam spherical hohlraum driven by 2ω laser light

Science.gov (United States)

Chen, Yao-Hua; Lan, Ke; Zheng, Wanguo; Campbell, E. M.

2018-02-01

The majority of solid state laser facilities built for laser fusion research irradiate targets with third harmonic light (0.35 μm) up-converted from the fundamental Nd wavelength at 1.05 μm. The motivation for this choice of wavelength is improved laser-plasma coupling. Significant disadvantages to this choice of wavelength are the reduced damage threshold of optical components and the efficiency of energy conversion to third harmonic light. Both these issues are significantly improved if second harmonic (0.53 μm) radiation is used, but theory and experiments have shown lower optical to x-ray energy conversion efficiency and increased levels of laser-plasma instabilities, resulting in reduced laser-target coupling. In this letter, we propose to use a 0.53 μm laser for the laser ignition facilities and use a low density foam wall to increase the coupling efficiency from the laser to the capsule and present two-dimensional radiation-hydrodynamic simulations of 0.53 μm laser light irradiating an octahedral-spherical hohlraum with a low density foam wall. The simulations show that the reduced optical depth of the foam wall leads to an increased laser-light conversion into thermal x-rays and about 10% higher radiation flux on the capsule than that achieved with 0.35 μm light irradiating a solid density wall commonly used in laser indirect drive fusion research. The details of the simulations and their implications and suggestions for wavelength scaling coupled with innovative hohlraum designs will be discussed.
Numerical evolutions of fields on the 2-sphere using a spectral method based on spin-weighted spherical harmonics

International Nuclear Information System (INIS)

Beyer, Florian; Daszuta, Boris; Frauendiener, Jörg; Whale, Ben

2014-01-01

Many applications in science call for the numerical simulation of systems on manifolds with spherical topology. Through the use of integer spin-weighted spherical harmonics, we present a method which allows for the implementation of arbitrary tensorial evolution equations. Our method combines two numerical techniques that were originally developed with different applications in mind. The first is Huffenberger and Wandelt’s spectral decomposition algorithm to perform the mapping from physical to spectral space. The second is the application of Luscombe and Luban’s method, to convert numerically divergent linear recursions into stable nonlinear recursions, to the calculation of reduced Wigner d-functions. We give a detailed discussion of the theory and numerical implementation of our algorithm. The properties of our method are investigated by solving the scalar and vectorial advection equation on the sphere, as well as the 2 + 1 Maxwell equations on a deformed sphere. (paper)
Modeling the Effects of Mirror Misalignment in a Ring Imaging Cherenkov Detector

Science.gov (United States)

Hitchcock, Tawanda; Harton, Austin; Garcia, Edmundo

2012-03-01

The Very High Momentum Particle Identification Detector (VHMPID) has been proposed for the ALICE experiment at the Large Hadron Collider (LHC). This detector upgrade is considered necessary to study jet-matter interaction at high energies. The VHMPID identifies charged hadrons in the 5 GeV/c to 25 GeV/c momentum range. The Cherenkov photons emitted in the VHMPID radiator are collected by spherical mirrors and focused onto a photo-detector plane forming a ring image. The radius of this ring is related to the Cherenkov angle, this information coupled with the particle momentum allows the particle identification. A major issue in the RICH detector is that environmental conditions can cause movements in mirror position. In addition, chromatic dispersion causes the refractive index to shift, altering the Cherenkov angle. We are modeling a twelve mirror RICH detector taking into account the effects of mirror misalignment and chromatic dispersion using a commercial optical software package. This will include quantifying the effects of both rotational and translational mirror misalignment for the initial assembly of the module and later on particle identification.
Mirrors design, analysis and manufacturing of the 550mm Korsch telescope experimental model

Science.gov (United States)

Huang, Po-Hsuan; Huang, Yi-Kai; Ling, Jer

2017-08-01

In 2015, NSPO (National Space Organization) began to develop the sub-meter resolution optical remote sensing instrument of the next generation optical remote sensing satellite which follow-on to FORMOSAT-5. Upgraded from the Ritchey-Chrétien Cassegrain telescope optical system of FORMOSAT-5, the experimental optical system of the advanced optical remote sensing instrument was enhanced to an off-axis Korsch telescope optical system which consists of five mirrors. It contains: (1) M1: 550mm diameter aperture primary mirror, (2) M2: secondary mirror, (3) M3: off-axis tertiary mirror, (4) FM1 and FM2: two folding flat mirrors, for purpose of limiting the overall volume, reducing the mass, and providing a long focal length and excellent optical performance. By the end of 2015, we implemented several important techniques including optical system design, opto-mechanical design, FEM and multi-physics analysis and optimization system in order to do a preliminary study and begin to develop and design these large-size lightweight aspheric mirrors and flat mirrors. The lightweight mirror design and opto-mechanical interface design were completed in August 2016. We then manufactured and polished these experimental model mirrors in Taiwan; all five mirrors ware completed as spherical surfaces by the end of 2016. Aspheric figuring, assembling tests and optical alignment verification of these mirrors will be done with a Korsch telescope experimental structure model in 2018.
Ultra-high performance mirror systems for the imaging and coherence beamline I13 at the Diamond Light Source

Science.gov (United States)

Wagner, U. H.; Alcock, S.; Ludbrook, G.; Wiatryzk, J.; Rau, C.

2012-05-01

I13L is a 250m long hard x-ray beamline (6 keV to 35 keV) currently under construction at the Diamond Light Source. The beamline comprises of two independent experimental endstations: one for imaging in direct space using x-ray microscopy and one for imaging in reciprocal space using coherent diffraction based imaging techniques. To minimise the impact of thermal fluctuations and vibrations onto the beamline performance, we are developing a new generation of ultra-stable beamline instrumentation with highly repeatable adjustment mechanisms using low thermal expansion materials like granite and large piezo-driven flexure stages. For minimising the beam distortion we use very high quality optical components like large ion-beam polished mirrors. In this paper we present the first metrology results on a newly designed mirror system following this design philosophy.
Elliptically Bent X-ray Mirrors with Active Temperature Stabilization

International Nuclear Information System (INIS)

Yuan, Sheng; Church, Matthew; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Rich; McKinney, Wayne R.; Kirschman, Jonathan; Morrison, Greg; Noll, Tino; Warwick, Tony; Padmore, Howard A.

2010-01-01

We present details of design of elliptically bent Kirkpatrick-Baez mirrors developed and successfully used at the Advanced Light Source for submicron focusing. A distinctive feature of the mirror design is an active temperature stabilization based on a Peltier element attached directly to the mirror body. The design and materials have been carefully optimized to provide high heat conductance between the mirror body and substrate. We describe the experimental procedures used when assembling and precisely shaping the mirrors, with special attention paid to laboratory testing of the mirror-temperature stabilization. For this purpose, the temperature dependence of the surface slope profile of a specially fabricated test mirror placed inside a temperature-controlled container was measured. We demonstrate that with active mirror-temperature stabilization, a change of the surrounding temperature by more than 3K does not noticeably affect the mirror figure. Without temperature stabilization, the surface slope changes by approximately 1.5 ?mu rad rms (primarily defocus) under the same conditions.
Elliptically Bent X-Ray Mirrors with Active Temperature Stabilization

International Nuclear Information System (INIS)

Yuan, S.; Church, M.; Yashchuk, V.V.; Celestre, R.S.; McKinney, W.R.; Morrison, G.; Warwick, T.; Padmore, H.A.; Goldberg, K.A.; Kirschman, J.; Noll, T.

2010-01-01

We present details of design of elliptically bent Kirkpatrick-Baez mirrors developed and successfully used at the advanced light source for submicron focusing. A distinctive feature of the mirror design is an active temperature stabilization based on a Peltier element attached directly to the mirror body. The design and materials have been carefully optimized to provide high heat conductance between the mirror body and substrate. We describe the experimental procedures used when assembling and precisely shaping the mirrors, with special attention paid to laboratory testing of the mirror-temperature stabilization. For this purpose, the temperature dependence of the surface slope profile of a specially fabricated test mirror placed inside a temperature-controlled container was measured. We demonstrate that with active mirror-temperature stabilization, a change of the surrounding temperature by more than 3 K does not noticeably affect the mirror figure. Without temperature stabilization, the rms slope error is changed by approximately 1.5 μrad (primarily defocus) under the same conditions
Light composite mirrors for RICH detectors Production, characterisation and stability tests

CERN Document Server

Bellunato, T F; Calvi, M; Chignoli, F; D'Ambrosio, C; Matteuzzi, C; Musy, M; Perego, D L

2005-01-01

The production of lightweight composite mirror prototypes suitable for application in Ring Imaging Cherenkov (RICH) detectors is described. The goal is the use of such mirrors whenever material budget is a concern. The manufacturing technique is described in detail, together with the achieved results in terms of optical quality. Several ageing tests have been performed on some of the prototypes. The results of these tests are reported.
Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students.

Science.gov (United States)

Hodgin, Katie L; Graham, Dan J

2016-01-01

Previous research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one's personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA) and the low percentage who actually meet PA participation standards. However, few studies have examined how mirror exposure and both perceived and actual body size influence highly valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI) would be more likely to take the stairs, and that body size distorting mirrors would impact the stair-elevator decision. One hundred sixty-seven students (51% male) enrolled in an introductory psychology course were recruited to take a survey about their "transportation choices" at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants' choice of floor-climbing method (stairs or elevator) was recorded, and they were administered an Internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror [odds ratios (OR) = 0.37, 95% CI: 0.14-0.96], males (OR = 0.33, 95% CI: 0.13-0.85), those with lower BMI (OR = 0.84, 95% CI: 0.71-0.99), those
Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students

Directory of Open Access Journals (Sweden)

Katie L Hodgin

2016-04-01

Full Text Available AbstractPrevious research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one’s personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA and the low percentage who actually meet PA participation standards. Few studies, however, have examined how mirror exposure and both perceived and actual body size influence highly-valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally-healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI would be more likely to take the stairs, and that body-size distorting mirrors would impact the stair-elevator decision. One hundred and sixty-seven students (51% male enrolled in an introductory psychology course were recruited to take a survey about their transportation choices at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants’ choice of floor climbing method (stairs or elevator was recorded and they were administered an internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror (OR = 0.37, 95% CI: 0.14 – 0.96, males (OR = 0.33, 95% CI: 0.13 – 0.85, those with lower BMI (OR = 0.84, 95% CI: 0.71 �
Obtaining the time evolution for spherically symmetric Lemaitre-Tolman-Bondi models given data on our past light cone

International Nuclear Information System (INIS)

Araujo, M. E.; Stoeger, W. R.

2009-01-01

A rigorous demonstration that given appropriate data on our past light cone leads to the determination of the metric functions and all their time derivatives on our past light cone is presented, thus showing how to evolve the solution we obtain from data on the light cone off it in a well-defined and straightforward way. It also automatically gives a procedure for constructing the solution for all spherically symmetric, inhomogeneous cosmological Lemaitre-Tolman-Bondi models in observational coordinates as a Taylor series in time of however many terms we need. Our procedure takes into account the essential data giving the maximum of the observer area (angular-diameter) distance, and the redshift z max at which that occurs. This enables the determination of the vacuum-energy density μ Λ , which would otherwise remain undetermined.
Thermal performance of heavy-weight and light-weight steel frame construction approaches in the central Pretoria climate

CSIR Research Space (South Africa)

Kumirai, T

2013-01-01

Full Text Available -1 Journal for New Generation Sciences Thermal performance of heavy-weight and light-weight steel frame construction approaches in the central Pretoria climate T Kumirai and DCU Conradie Built Environment, Council for Scientific and Industrial...

Concept and design of an alignment monitoring system for the CBM RICH mirrors

Energy Technology Data Exchange (ETDEWEB)

Bendarouach, Jordan [Justus Liebig University (Germany); Collaboration: CBM-Collaboration

2016-07-01

The Compressed Baryonic Matter (CBM) experiment at the future FAIR (Facility for Antiproton and Ion Research) complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures in A+A collisions from 2-11 AGeV (SIS100) beam energy. One of the key detector components required for this CBM physics program is the RICH (Ring Imaging CHerenkov) detector, developed for efficient and clean electron identification and pion suppression. The detector consists of about 80 spherical glass mirror tiles, distributed over two sphere parts. An important aspect to guarantee a stable operation of the RICH detector is the alignment of the mirrors. A method originally developed and inspired by the HERA-B experiment uses recorded data to assess mirror alignment of the RICH mirror system. Measurements of Cherenkov distances and angles on the PMT plane may reveal potential misalignments of the considered tile. If mirror misalignment is revealed, it can be subsequently included and rectified by correction routines, which should mostly increase ring reconstruction as well as ring-track matching efficiencies. Results of this alignment method based on simulated events, reproducing potential mirror misalignments, its limits and first correction routines are presented.
The Scallop's Eye--A Concave Mirror in the Context of Biology

Science.gov (United States)

Colicchia, Giuseppe; Waltner, Christine; Hopf, Martin; Wiesner, Hartmut

2009-01-01

Teaching physics in the context of medicine or biology is a way to generate students' interest in physics. A more uncommon type of eye, the scallop's eye (an eye with a spherical concave mirror, which is similar to a Newtonian or Schmidt telescope) and the image-forming mechanism in this eye are described. Also, a simple eye model, which can…
The Development of light-weight 2-link robot arm for high radiation area

Energy Technology Data Exchange (ETDEWEB)

Shin, Ho Cheol; Seo, Yong Chil; Jung, Kyung Min; Choi, Young Soo

2009-10-15

A light-weight 2-link robot arm which weight is less than 8kg was developed for treating the small radio-active material in the high radiation area such as nuclear power plants and NDT area. The light-weight 2-link robot arm can be attached on a small mobile robot and carry out tasks. It is a 5 DOF robot arm including a gripper
Surface Slope Metrology on Deformable Soft X-ray Mirrors

International Nuclear Information System (INIS)

Yuan, Sheng; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Rich; Church, Matthew; McKinney, Wayne R.; Morrison, Greg; Warwick, Tony

2010-01-01

We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situ visible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.
Surface Slope Metrology on Deformable Soft X-ray Mirrors

International Nuclear Information System (INIS)

Yuan, S.; Yashchuk, V.V.; Goldberg, K.A.; Celestre, R.; Church, M.; McKinney, W.R.; Morrison, G.; Warwick, T.

2009-01-01

We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situvisible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.
Process of constructing a lightweight x-ray flight mirror assembly

Science.gov (United States)

McClelland, Ryan S.; Biskach, Michael P.; Chan, Kai-Wing; Espina, Rebecca A.; Hohl, Bruce R.; Saha, Timo T.; Zhang, William W.

2014-07-01

Lightweight and high resolution optics are needed for future space-based x-ray telescopes to achieve advances in highenergy astrophysics. NASA's Next Generation X-ray Optics (NGXO) project has made significant progress towards building such optics, both in terms of maturing the technology for spaceflight readiness and improving the angular resolution. Technology Development Modules (TDMs) holding three pairs of mirrors have been regularly and repeatedly integrated and tested both for optical performance and mechanical strength. X-ray test results have been improved over the past year from 10.3 arc-seconds Half Power Diameter (HPD) to 8.3 arc-seconds HPD. A vibration test has been completed to NASA standard verification levels showing the optics can survive launch and pointing towards improvements in strengthening the modules through redundant bonds. A Finite Element Analysis (FEA) study was completed which shows the mirror distortion caused by bonding is insensitive to the number of bonds. Next generation TDMs, which will demonstrate a lightweight structure and mount additional pairs of mirrors, have been designed and fabricated. The light weight of the module structure is achieved through the use of E-60 Beryllium Oxide metal matrix composite material. As the angular resolution of the development modules has improved, gravity distortion during horizontal x-ray testing has become a limiting factor. To address this issue, a facility capable of testing in the vertical orientation has been designed and planned. Test boring at the construction site suggest standard caisson construction methods can be utilized to install a subterranean vertical vacuum pipe. This facility will also allow for the testing of kinematically mounted mirror segments, which greatly reduces the effect of bonding displacements. A development platform demonstrating the feasibility of kinematically mounting mirror segments has been designed, fabricated, and successfully tested.
A generalized ray-tracing procedure for an atmospheric Cherenkov imaging telescope and optical characteristics of the TACTIC light collector

International Nuclear Information System (INIS)

Tickoo, A.K.; Suthar, R.L.; Koul, R.; Sapru, M.L.; Kumar, N.; Kaul, C.L.; Yadav, K.K.; Thoudam, S.; Kaul, S.K.; Venugopal, K.; Kothari, M.; Goyal, H.C.; Chandra, P.; Dhar, V.K.; Rannot, R.C.; Koul, M.K.; Kaul, S.R.

2005-01-01

A generalized ray-tracing procedure has been developed, which facilitates the design of a multimirror-based light collector used in atmospheric Cherenkov telescopes. This procedure has been employed to study the optical characteristics of the 3.5 m diameter light collector of the TACTIC Imaging telescope. Comparison of the measured point-spread function of the light collector with the simulated performance of ideal Davies-Cotton and paraboloid designs has been made to determine an optimum arrangement of the 34 spherical mirror facets used in the telescope to obtain the best possible point-spread function. A description of the ray-tracing subroutine used for processing CORSIKA-generated Cherenkov data, required for carrying out Monte-Carlo simulation studies, is also discussed in the paper
Improved methods for dewarping images in convex mirrors in fine art: applications to van Eyck and Parmigianino

Science.gov (United States)

Usami, Yumi; Stork, David G.; Fujiki, Jun; Hino, Hideitsu; Akaho, Shotaro; Murata, Noboru

2011-03-01

We derive and demonstrate new methods for dewarping images depicted in convex mirrors in artwork and for estimating the three-dimensional shapes of the mirrors themselves. Previous methods were based on the assumption that mirrors were spherical or paraboloidal, an assumption unlikely to hold for hand-blown glass spheres used in early Renaissance art, such as Johannes van Eyck's Portrait of Giovanni (?) Arnolfini and his wife (1434) and Robert Campin's Portrait of St. John the Baptist and Heinrich von Werl (1438). Our methods are more general than such previous methods in that we assume merely that the mirror is radially symmetric and that there are straight lines (or colinear points) in the actual source scene. We express the mirror's shape as a mathematical series and pose the image dewarping task as that of estimating the coefficients in the series expansion. Central to our method is the plumbline principle: that the optimal coefficients are those that dewarp the mirror image so as to straighten lines that correspond to straight lines in the source scene. We solve for these coefficients algebraically through principal component analysis, PCA. Our method relies on a global figure of merit to balance warping errors throughout the image and it thereby reduces a reliance on the somewhat subjective criterion used in earlier methods. Our estimation can be applied to separate image annuli, which is appropriate if the mirror shape is irregular. Once we have found the optimal image dewarping, we compute the mirror shape by solving a differential equation based on the estimated dewarping function. We demonstrate our methods on the Arnolfini mirror and reveal a dewarped image superior to those found in prior work|an image noticeably more rectilinear throughout and having a more coherent geometrical perspective and vanishing points. Moreover, we find the mirror deviated from spherical and paraboloidal shape; this implies that it would have been useless as a concave
Single-crystalline spherical β-Ga2O3 particles: Synthesis, N-doping and photoluminescence properties

International Nuclear Information System (INIS)

Zhang, Tingting; Lin, Jing; Zhang, Xinghua; Huang, Yang; Xu, Xuewen; Xue, Yanming; Zou, Jin; Tang, Chengchun

2013-01-01

We report on the synthesis of single-crystalline spherical β-Ga 2 O 3 particles by a simple method in ambient atmosphere. No pre-treatment, catalyst, substrate, or gas flow was required during the synthesis process. The well-dispersed Ga 2 O 3 particles display uniform spherical morphology with an average diameter of ∼200 nm. Photoluminescence studies indicate that the Ga 2 O 3 particles exhibit a broad blue-green light emission and an interesting red light emission at room temperature. The red light emission can be further tuned by post-annealing of the particles in ammonia atmosphere. The present single-crystalline β-Ga 2 O 3 particles with spherical morphology, uniform sub-micrometer sizes and tunable light emission are envisaged to be of high promise for applications in white-LED phosphors and optoelectronic devices. -- Highlights: ► We prepared single-crystalline spherical β-Ga 2 O 3 particles in ambient atmosphere. ► The particles display uniform spherical morphology with an average diameter of ∼200 nm. ► The Ga 2 O 3 particles exhibit a broad blue-green light and an interesting red light emission. ► The red light emission can be further tuned by post-annealing of the particles
Error reduction techniques for measuring long synchrotron mirrors

International Nuclear Information System (INIS)

Irick, S.

1998-07-01

Many instruments and techniques are used for measuring long mirror surfaces. A Fizeau interferometer may be used to measure mirrors much longer than the interferometer aperture size by using grazing incidence at the mirror surface and analyzing the light reflected from a flat end mirror. Advantages of this technique are data acquisition speed and use of a common instrument. Disadvantages are reduced sampling interval, uncertainty of tangential position, and sagittal/tangential aspect ratio other than unity. Also, deep aspheric surfaces cannot be measured on a Fizeau interferometer without a specially made fringe nulling holographic plate. Other scanning instruments have been developed for measuring height, slope, or curvature profiles of the surface, but lack accuracy for very long scans required for X-ray synchrotron mirrors. The Long Trace Profiler (LTP) was developed specifically for long x-ray mirror measurement, and still outperforms other instruments, especially for aspheres. Thus, this paper focuses on error reduction techniques for the LTP
Optimization of an Angle-Aided Mirror Diversity Receiver for Indoor MIMO-VLC Systems

KAUST Repository

Park, Kihong

2017-02-07

In this paper, we investigate the channel correlation problem which affects the performance of indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. More specifically, in order to reduce the high correlation of channel matrix in MIMO-VLC intensity channel, we propose a non-imaging receiver called angle-aided mirror diversity receiver (AMDR) which utilizes not only a mirror placement but also a variation of orientation angle for the photodetector (PD) plane. Deploying a mirror helps reducing the correlation by blocking the reception of the light in one specific direction and by receiving additional light reflected in the mirror in another direction, while orienting the angle of PD plane into specific direction enables the directional reception of light. Applying a zero-forcing decorrelator at the receiver, we analyze the bit error rate (BER) performance for a 2×2 multiplexing MIMO-VLC system using a 2-dimensional geometric model. In particular, we formulate a min-max BER problem and find the optimal height of mirror and elevation angle of PD plane. Some selected numerical results validate our proposed optimal solution to our min-max BER problem and show that the BER performance of our proposed AMDR outperforms that of the previous non-imaging receivers.
Optimization of an Angle-Aided Mirror Diversity Receiver for Indoor MIMO-VLC Systems

KAUST Repository

Park, Kihong; Alouini, Mohamed-Slim

2017-01-01

In this paper, we investigate the channel correlation problem which affects the performance of indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. More specifically, in order to reduce the high correlation of channel matrix in MIMO-VLC intensity channel, we propose a non-imaging receiver called angle-aided mirror diversity receiver (AMDR) which utilizes not only a mirror placement but also a variation of orientation angle for the photodetector (PD) plane. Deploying a mirror helps reducing the correlation by blocking the reception of the light in one specific direction and by receiving additional light reflected in the mirror in another direction, while orienting the angle of PD plane into specific direction enables the directional reception of light. Applying a zero-forcing decorrelator at the receiver, we analyze the bit error rate (BER) performance for a 2×2 multiplexing MIMO-VLC system using a 2-dimensional geometric model. In particular, we formulate a min-max BER problem and find the optimal height of mirror and elevation angle of PD plane. Some selected numerical results validate our proposed optimal solution to our min-max BER problem and show that the BER performance of our proposed AMDR outperforms that of the previous non-imaging receivers.
Innovative lightweight substrate for stable optical benches and mirrors

Science.gov (United States)

Rugi Grond, E.; Herren, A.; Mérillat, S.; Fermé, J. J.

2017-11-01

High precision space optics, such as spectrometers, relay optics, and filters, require ultra stable, lightweight platforms. These equipped platforms have on one side to survive the launch loads, on the other side they have to maintain their stability also under the varying thermal loads occurring in space. Typically such platforms have their equipment (prisms, etalons, beam expanders, etc.) mounted by means of classical bonding, hydro-catalytic bonding or optical contacting. Therefore such an optical bench requires to provide an excellent flatness, minimal roughness and is usually made of the same material as the equipment it carries (glass, glass ceramics). For space systems, mass is a big penalty, therefore such optical platforms are in most cases light weighted by means of machining features (i.e. pockets). Besides of being not extremely mass efficient, such pockets reduce the load carrying capability of the base material significantly. The challenge for Oerlikon Space, in this context, was to develop, qualify and deliver such optical benches, providing a substantial mass reduction compared to actual light weighted systems, while maintaining most of the full load carrying capacity of the base material. Additionally such a substrate can find an attractive application for mirror substrates. The results of the first development and of the first test results will be presented.
Rise to SUMMIT: the Sydney University Multiple-Mirror Telescope

Science.gov (United States)

Moore, Anna M.; Davis, John

2000-07-01

The Sydney University Multiple Mirror Telescope (SUMMIT) is a medium-sized telescope designed specifically for high resolution stellar spectroscopy. Throughout the design emphasis has been placed on high efficiency at low cost. The telescope consists of four 0.46 m diameter mirrors mounted on a single welded steel frame. Specially designed mirror cells support and point each mirror, allowing accurate positioning of the images on optical fibers located at the foci of the mirrors. Four fibers convey the light to the future location of a high resolution spectrograph away from the telescope in a stable environment. An overview of the commissioning of the telescope is presented, including the guidance and automatic mirror alignment and focussing systems. SUMMIT is located alongside the Sydney University Stellar Interferometer at the Paul Wild Observatory, near Narrabri, Northern New South Wales.
Thermal properties of light-weight concrete with waste polypropylene aggregate

Science.gov (United States)

Záleská, Martina; Pokorný, Jaroslav; Pavlíková, Milena; Pavlík, Zbyšek

2017-07-01

Thermal properties of a sustainable light-weight concrete incorporating high volume of waste polypropylene as partial substitution of natural aggregate were studied in the paper. Glass fiber reinforced polypropylene (GFPP), a by-product of PP tubes production, partially substituted fine natural silica aggregate in 10, 20, 30, 40, and 50 mass%. In order to quantify the effect of GFPP use on concrete properties, a reference concrete mix without plastic waste was studied as well. For the applied GFPP, bulk density, matrix density, and particle size distribution were measured. Specific attention was paid to thermal transport and storage properties of GFPP that were examined in dependence on compaction time. For the developed light-weight concrete, thermal properties were accessed using transient impulse technique, whereas the measurement was done in dependence on moisture content, from the dry state to fully water saturated state. Additionally, the investigated thermal properties were plotted as function of porosity. The tested light-weight concrete was found to be prospective construction material possessing improved thermal insulation function. Moreover, the reuse of waste plastics in concrete composition was beneficial both from the environmental and financial point of view considering plastics low biodegradability and safe disposal.
Stereo photograph of atomic arrangement by circularly-polarized-light two-dimensional photoelectron spectroscopy

International Nuclear Information System (INIS)

Daimon, Hiroshi

2003-01-01

A stereo photograph of atomic arrangement was obtained for the first time. The stereo photograph was displayed directly on the screen of display-type spherical-mirror analyzer without any computer-aided conversion process. This stereo photography was realized taking advantage of the phenomenon of circular dichroism in photoelectron angular distribution due to the reversal of orbital angular momentum of photoelectrons. The azimuthal shifts of forward focusing peaks in a photoelectron angular distribution pattern taken with left and right helicity light in a special arrangement are the same as the parallaxes in a stereo view of atoms. Hence a stereoscopic recognition of three-dimensional atomic arrangement is possible, when the left eye and the right eye respectively view the two images obtained by left and right helicity light simultaneously. (author)
data sets Simulations in articulating light-weight PRS

NARCIS (Netherlands)

Van den Berg, Bert

2008-01-01

The data sets are output of 3 different steps in the development a simulations of a PRS as described in chapter 3.3: Simulations in articulating light-weight PRS A case for Pedagogy-oriented and Rating-based Hybrid Recommendation Strategies Rob Nadolski, Bert van den Berg, Adriana Berlanga, Hans
Scattering-free optical levitation of a cavity mirror.

Science.gov (United States)

Guccione, G; Hosseini, M; Adlong, S; Johnsson, M T; Hope, J; Buchler, B C; Lam, P K

2013-11-01

We demonstrate the feasibility of levitating a small mirror using only radiation pressure. In our scheme, the mirror is supported by a tripod where each leg of the tripod is a Fabry-Perot cavity. The macroscopic state of the mirror is coherently coupled to the supporting cavity modes allowing coherent interrogation and manipulation of the mirror motion. The proposed scheme is an extreme example of the optical spring, where a mechanical oscillator is isolated from the environment and its mechanical frequency and macroscopic state can be manipulated solely through optical fields. We model the stability of the system and find a three-dimensional lattice of trapping points where cavity resonances allow for buildup of optical field sufficient to support the weight of the mirror. Our scheme offers a unique platform for studying quantum and classical optomechanics and can potentially be used for precision gravitational field sensing and quantum state generation.
Coherent dynamics of plasma mirrors

Energy Technology Data Exchange (ETDEWEB)

Thaury, C; George, H; Quere, F; Monot, P; Martin, Ph [CEA, DSM, IRAMIS, Serv Photons Atomes and Mol, F-91191 Gif Sur Yvette, (France); Loch, R [Univ Twente, Laser Phys and Nonlinear Opt Grp, Fac Sci and Technol, MESA Inst Nanotechnol, NL-7500 AE Enschede, (Netherlands); Geindre, J P [Ecole Polytech, Lab Pour Utilisat Lasers Intenses, CNRS, F-91128 Palaiseau, (France)

2008-07-01

Coherent ultrashort X-ray pulses provide new ways to probe matter and its ultrafast dynamics. One of the promising paths to generate these pulses consists of using a nonlinear interaction with a system to strongly and periodically distort the waveform of intense laser fields, and thus produce high-order harmonics. Such distortions have so far been induced by using the nonlinear polarizability of atoms, leading to the production of atto-second light bursts, short enough to study the dynamics of electrons in matter. Shorter and more intense atto-second pulses, together with higher harmonic orders, are expected by reflecting ultra intense laser pulses on a plasma mirror - a dense (approximate to 10{sup 23} electrons cm{sup -3}) plasma with a steep interface. However, short-wavelength-light sources produced by such plasmas are known to generally be incoherent. In contrast, we demonstrate that like in usual low-intensity reflection, the coherence of the light wave is preserved during harmonic generation on plasma mirrors. We then exploit this coherence for interferometric measurements and thus carry out a first study of the laser-driven coherent dynamics of the plasma electrons. (authors)
A pseudospectral matrix method for time-dependent tensor fields on a spherical shell

International Nuclear Information System (INIS)

Brügmann, Bernd

2013-01-01

We construct a pseudospectral method for the solution of time-dependent, non-linear partial differential equations on a three-dimensional spherical shell. The problem we address is the treatment of tensor fields on the sphere. As a test case we consider the evolution of a single black hole in numerical general relativity. A natural strategy would be the expansion in tensor spherical harmonics in spherical coordinates. Instead, we consider the simpler and potentially more efficient possibility of a double Fourier expansion on the sphere for tensors in Cartesian coordinates. As usual for the double Fourier method, we employ a filter to address time-step limitations and certain stability issues. We find that a tensor filter based on spin-weighted spherical harmonics is successful, while two simplified, non-spin-weighted filters do not lead to stable evolutions. The derivatives and the filter are implemented by matrix multiplication for efficiency. A key technical point is the construction of a matrix multiplication method for the spin-weighted spherical harmonic filter. As example for the efficient parallelization of the double Fourier, spin-weighted filter method we discuss an implementation on a GPU, which achieves a speed-up of up to a factor of 20 compared to a single core CPU implementation

Line focus by the ellipsoidal and hyperbolic mirrors, and the fabrication of the new type`s heated air engine. 1; Daenmenkyo to sokyokumenkyo ni yoru line focus to shingata netsu kuki engine no shisaku. 1

Energy Technology Data Exchange (ETDEWEB)

Shishido, K; Kazimierski, Z; Shoji, T [Tohoku Gakuin University, Sendai (Japan). Faculty of Engineering; Sugiura, M [Tohoku Gakuin Tsutsujigaoka High School, Sendai (Japan); Kobayashi, Y [Tokyo Special Glass Co. Ltd., Tokyo (Japan)

1996-10-27

Line focusing by ellipsoidal and hyperbolic mirrors was devised for solar heat collection, and the new prototype heated air engine is under fabrication based on such focusing. Ellipse is a locus of the point at which the distance from the 2nd focus is equal to that from the circle with the 1st focus as a center and the major axis as a radius. Hyperbola can be also figured under similar geometric conditions. The link mechanism possible to machine quadratic surfaces based on the above principle has been developed. High-precision quadratic surface mirrors can be fabricated by the link mechanism for convergent solar heat power generation, achieving line focusing of light. The new prototype heated air engine is also proposed which is composed of the heating part by line focusing, cylinder, piston and cooling column. This engine is featured by simple function, light weight, compact body, high efficiency and safety, and is under fabrication. Although conventional converging mirrors use all the mirror surface, the new line focusing uses only the upper part of the mirror, and the lower part is turned over for protection of the mirror from strong wind. 9 figs.
Mirror Fusion Test Facility magnet

International Nuclear Information System (INIS)

Henning, C.H.; Hodges, A.J.; Van Sant, J.H.; Hinkle, R.E.; Horvath, J.A.; Hintz, R.E.; Dalder, E.; Baldi, R.; Tatro, R.

1979-01-01

The Mirror Fusion Test Facility (MFTF) is the largest of the mirror program experiments for magnetic fusion energy. It seeks to combine and extend the near-classical plasma confinement achieved in 2XIIB with the most advanced neutral-beam and magnet technologies. The product of ion density and confinement time will be improved more than an order of magnitude, while the superconducting magnet weight will be extrapolated from the 15 tons in Baseball II to 375 tons in MFTF. Recent reactor studies show that the MFTF will traverse much of the distance in magnet technology towards the reactor regime. Design specifics of the magnet are given
Experimental study and analytical model of deformation of magnetostrictive films as applied to mirrors for x-ray space telescopes.

Science.gov (United States)

Wang, Xiaoli; Knapp, Peter; Vaynman, S; Graham, M E; Cao, Jian; Ulmer, M P

2014-09-20

The desire for continuously gaining new knowledge in astronomy has pushed the frontier of engineering methods to deliver lighter, thinner, higher quality mirrors at an affordable cost for use in an x-ray observatory. To address these needs, we have been investigating the application of magnetic smart materials (MSMs) deposited as a thin film on mirror substrates. MSMs have some interesting properties that make the application of MSMs to mirror substrates a promising solution for making the next generation of x-ray telescopes. Due to the ability to hold a shape with an impressed permanent magnetic field, MSMs have the potential to be the method used to make light weight, affordable x-ray telescope mirrors. This paper presents the experimental setup for measuring the deformation of the magnetostrictive bimorph specimens under an applied magnetic field, and the analytical and numerical analysis of the deformation. As a first step in the development of tools to predict deflections, we deposited Terfenol-D on the glass substrates. We then made measurements that were compared with the results from the analytical and numerical analysis. The surface profiles of thin-film specimens were measured under an external magnetic field with white light interferometry (WLI). The analytical model provides good predictions of film deformation behavior under various magnetic field strengths. This work establishes a solid foundation for further research to analyze the full three-dimensional deformation behavior of magnetostrictive thin films.
Mirroring

DEFF Research Database (Denmark)

Wegener, Charlotte; Wegener, Gregers

2016-01-01

and metaphorical value of mirroring for creativity theory across two different research fields — neuroscience and learning. We engage in a mutual (possibly creative) exploration of mirroring from ‘mirror neurons’ to mirroring in social learning theory. One of the most fascinating aspects of mirroring...... as a neurobiological and as a learning phenomenon is that it points to the embodied and unconscious aspects of social interaction. Thus, mirroring should not be reduced to the non-creative, mechanical repetition of the original, outstanding creativity. To mirror is a human capability built into our capacity to create......Most definitions of creativity emphasise originality. The creative product is recognised as distinct from other products and the creative person as someone who stands out from the crowd. What tend to be overlooked are acts of mirroring as a crucial element of the creative process. The human ability...
Quantizing the electromagnetic field near two-sided semitransparent mirrors

Science.gov (United States)

Furtak-Wells, Nicholas; Clark, Lewis A.; Purdy, Robert; Beige, Almut

2018-04-01

This paper models light scattering through flat surfaces with finite transmission, reflection, and absorption rates, with wave packets approaching the mirror from both sides. While using the same notion of photons as in free space, our model also accounts for the presence of mirror images and the possible exchange of energy between the electromagnetic field and the mirror surface. To test our model, we derive the spontaneous decay rate and the level shift of an atom in front of a semitransparent mirror as a function of its transmission and reflection rates. When considering limiting cases and using standard approximations, our approach reproduces well-known results but it also paves the way for the modeling of more complex scenarios.
Light-weight analyzer for odor recognition

Energy Technology Data Exchange (ETDEWEB)

Vass, Arpad A; Wise, Marcus B

2014-05-20

The invention provides a light weight analyzer, e.g., detector, capable of locating clandestine graves. The detector utilizes the very specific and unique chemicals identified in the database of human decompositional odor. This detector, based on specific chemical compounds found relevant to human decomposition, is the next step forward in clandestine grave detection and will take the guess-work out of current methods using canines and ground-penetrating radar, which have historically been unreliable. The detector is self contained, portable and built for field use. Both visual and auditory cues are provided to the operator.
LUTE primary mirror materials and design study report

Science.gov (United States)

Ruthven, Greg

1993-02-01

The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.
Mirror Station for studies of the protection of diagnostic mirrors from impurity contamination in ITER: Design and first results

International Nuclear Information System (INIS)

Litnovsky, Andrey; Krasikov, Yuri; Kotov, Vladislav; Matveeva, Maria; Panin, Anatoly; Vera, Liliana; Buzi, Luxherta; Neubauer, Olaf; Biel, Wolfgang; Nicolai, Dirk; Mertens, Philippe; Linsmeier, Christian

2015-01-01

Highlights: • Paper is devoted to protection of diagnostic mirrors for ITER. • Modeling predicts suppression of impurity deposition on mirrors by using ducts. • The mirror tube system (Mirror Station) was built to validate the model. • The Mirror Station was exposed in TEXTOR. • The decrease of deposition in cylindrical ducts with fins cannot be confirmed. • All mirrors located in conical ducts preserved their reflectivity. - Abstract: Optical and laser-based diagnostics in ITER will use mirrors to transmit plasma radiation and laser light to the corresponding detectors and cameras. Mirrors will be sputtered by the fast plasma particles and contaminated by impurities leading to the degradation of the reflectivity and hampering the performance of corresponding diagnostics. Dedicated measures were proposed to minimize the impurity deposition comprising the use of shutters and fins inside diagnostic ducts to trap impurities on their way toward the mirror located in the end of these ducts. Modeling results predict at least 7-fold suppression of the deposition for the duct having four fins located at the distance of a half of a diameter from each other. The Mirror Station (MS) was designed to validate modeling predictions and to study the suppression of deposition inside of diagnostic ducts. The MS contained cylindrical and cone-shaped tubes of different lengths with smooth and shaped geometry of ducts. The MS was exposed in the midplane port of TEXTOR for about 3960 s of plasma operation. After exposure, no drastic suppression of deposition was observed in the cylindrical ducts with fins. In the conical tubes no deposition was detected outlining the advantages of a cone form.
Reflections on a Disco Ball

Science.gov (United States)

Ribeiro, Jair Lúcio Prados

2016-01-01

A disco ball is a spherical object covered with small plane mirrors. When light reflects on these mirrors, it is scattered in many directions, producing a novel effect. The mirror globe is usually set to rotate, creating a profusion of moving spots (Fig. 1). In this article, we present a geometrical description of the movement of these spots and…
Fast force actuators for LSST primary/tertiary mirror

Science.gov (United States)

Hileman, Edward; Warner, Michael; Wiecha, Oliver

2010-07-01

The very short slew times and resulting high inertial loads imposed upon the Large Synoptic Survey Telescope (LSST) create new challenges to the primary mirror support actuators. Traditionally large borosilicate mirrors are supported by pneumatic systems, which is also the case for the LSST. These force based actuators bear the weight of the mirror and provide active figure correction, but do not define the mirror position. A set of six locating actuators (hardpoints) arranged in a hexapod fashion serve to locate the mirror. The stringent dynamic requirements demand that the force actuators must be able to counteract in real time for dynamic forces on the hardpoints during slewing to prevent excessive hardpoint loads. The support actuators must also maintain the prescribed forces accurately during tracking to maintain acceptable mirror figure. To meet these requirements, candidate pneumatic cylinders incorporating force feedback control and high speed servo valves are being tested using custom instrumentation with automatic data recording. Comparative charts are produced showing details of friction, hysteresis cycles, operating bandwidth, and temperature dependency. Extremely low power actuator controllers are being developed to avoid heat dissipation in critical portions of the mirror and also to allow for increased control capabilities at the actuator level, thus improving safety, performance, and the flexibility of the support system.
Development of a light-weight beryllium Cassegrain telescope: from the optical design to the performance measurement

Science.gov (United States)

Viertl, Jacques; Greger, Ralf; Di Domenico, Maurizio; Francou, Laurent; Ellouzi, Marina; Blum, Steffen; Kudielka, Klaus; Weigel, Thomas; Rugi Grond, Elisabetta; Piazza, Daniele

2012-12-01

The BepiColombo Laser Altimeter (BELA) is selected to fly on board of the ESA's BepiColombo Mercury Planetary Orbiter (MPO). The instrument will be the first European planetary laser altimeter system. RUAG Space is the industrial prime for the Receiver part of the scientific instrument. The BELA Receiver is a joined effort of Swiss industries under the leading role of RUAG and University of Bern as co-Prime. A core element is the light weighted Receiver Telescope (RTL), to collect the laser pulse reflected from the planet's surface. An innovative design was required to deal with the very challenging Mercury's environmental conditions and with the very stringent instrument's mass budget. The Optothermo- mechanical analyses lead to the design of a 1250mm focal length Cassegrain telescope made of Beryllium. It provides an aperture of 204 mm diameter and a 2 mm thick primary mirror for a total mass of less than 600gr. The manufacturing and the integration needed special developments. This paper presents the design analyses and the major challenges which had to be solved. Discussing some aspects of the telescope integration and test campaign, the finally achieved performances and lessons learnt will be presented.
Smart Makeup Mirror: Computer Augmented Mirror to Aid Makeup Application

OpenAIRE

岩渕, 絵里子; 椎尾, 一郎

2008-01-01

In this paper, we present the system that aids people in wearing makeup easily and make the process enjoyable. The proposed system is the Smart Makeup Mirror device, which is an electronic dressing table that facilitates the process of makeup application. In this system, we place a high-resolution camera on top of a computer display. We developed some functions such as Automatic zoom to a specific part of the face, Display our face from various angles , and Simulation of the lighting conditio...
Measurement and analysis of active synchrotron mirrors under operating conditions

Science.gov (United States)

Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

2013-05-01

At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler-Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans.
Measurement and analysis of active synchrotron mirrors under operating conditions

International Nuclear Information System (INIS)

Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

2013-01-01

At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler–Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans
Construction and Optical Testing of Inflatable Membrane Mirror Using Structured Light Technique

Directory of Open Access Journals (Sweden)

Felipe Patiño-Jiménez

2015-01-01

Full Text Available Construction and characterization of an inflatable mirror prototype made out of flexible polymeric membranes are being presented. Surfaces were curved by imposing a slight excess of air pressure. Lightweighted, lowcost, and commercially available materials were selected in order to produce solar concentration elements at competitive prices. In this sense, large-area, image-forming mirrors with low optical acuity were achieved by concentration purposes. Optical characterization of the mirror’s shape at a given pressure or curvature radius was done by means of a structuredlight technique with a resolution of 0.1 mm finding a conical shape acquired by the inflated mirror as the best approximation. Concentration ratio achieved for a focal length of 5068 mm was of 25.1 suns, making a promising approach for lowering initial investment costs in applications such as hot-water, parabolic dish with Stirling engines, or concentrated photovoltaic electricity generation.
Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal.

Science.gov (United States)

Corballis, Michael C

2018-01-01

Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d ) must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.
Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal

Directory of Open Access Journals (Sweden)

Michael C. Corballis

2018-04-01

Full Text Available Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.
Simulation of mirror surfaces for virtual estimation of visibility lines for 3D motor vehicle collision reconstruction.

Science.gov (United States)

Leipner, Anja; Dobler, Erika; Braun, Marcel; Sieberth, Till; Ebert, Lars

2017-10-01

3D reconstructions of motor vehicle collisions are used to identify the causes of these events and to identify potential violations of traffic regulations. Thus far, the reconstruction of mirrors has been a problem since they are often based on approximations or inaccurate data. Our aim with this paper was to confirm that structured light scans of a mirror improve the accuracy of simulating the field of view of mirrors. We analyzed the performances of virtual mirror surfaces based on structured light scans using real mirror surfaces and their reflections as references. We used an ATOS GOM III scanner to scan the mirrors and processed the 3D data using Geomagic Wrap. For scene reconstruction and to generate virtual images, we used 3ds Max. We compared the simulated virtual images and photographs of real scenes using Adobe Photoshop. Our results showed that we achieved clear and even mirror results and that the mirrors behaved as expected. The greatest measured deviation between an original photo and the corresponding virtual image was 20 pixels in the transverse direction for an image width of 4256 pixels. We discussed the influences of data processing and alignment of the 3D models on the results. The study was limited to a distance of 1.6m, and the method was not able to simulate an interior mirror. In conclusion, structured light scans of mirror surfaces can be used to simulate virtual mirror surfaces with regard to 3D motor vehicle collision reconstruction. Copyright © 2017 Elsevier B.V. All rights reserved.
Mirror Neurons and Mirror-Touch Synesthesia.

Science.gov (United States)

Linkovski, Omer; Katzin, Naama; Salti, Moti

2016-05-30

Since mirror neurons were introduced to the neuroscientific community more than 20 years ago, they have become an elegant and intuitive account for different cognitive mechanisms (e.g., empathy, goal understanding) and conditions (e.g., autism spectrum disorders). Recently, mirror neurons were suggested to be the mechanism underlying a specific type of synesthesia. Mirror-touch synesthesia is a phenomenon in which individuals experience somatosensory sensations when seeing someone else being touched. Appealing as it is, careful delineation is required when applying this mechanism. Using the mirror-touch synesthesia case, we put forward theoretical and methodological issues that should be addressed before relying on the mirror-neurons account. © The Author(s) 2016.
Plasma mirrors for ultrahigh-intensity optics

Energy Technology Data Exchange (ETDEWEB)

Thaury, C; Quere, F; Levy, A; Ceccotti, T; Monot, P; Bougeard, M; Reau, F; D' Oliveira, P; Martin, PH [CEA, DSM, DRECAM, Serv Photons Atomes and Mol, F-91191 Gif Sur Yvette, (France); Geindre, J P; Audebert, P [Ecole Polytech, CNRS, Lab Utilisat Lasers Inst, F-91128 Palaiseau, (France); Marjoribanks, R [Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, (Canada); Marjoribanks, R [Univ Toronto, Inst Opt Sci, Toronto, ON M5S 1A7, (Canada)

2007-07-01

Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven atto-second sources for use in fields from materials science to molecular biology. (authors)

Plasma mirrors for ultrahigh-intensity optics

International Nuclear Information System (INIS)

Thaury, C.; Quere, F.; Levy, A.; Ceccotti, T.; Monot, P.; Bougeard, M.; Reau, F.; D'Oliveira, P.; Martin, PH.; Geindre, J.P.; Audebert, P.; Marjoribanks, R.; Marjoribanks, R.

2007-01-01

Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven atto-second sources for use in fields from materials science to molecular biology. (authors)
Focusing X-rays to a 1-μm spot using elastically bent, graded multilayer coated mirrors

International Nuclear Information System (INIS)

Underwood, J.H.; Thompson, A.C.; Kortright, J.B.

1997-01-01

In the x-ray fluorescent microprobe at beamline 10.3.1, the ALS bending magnet source is demagnified by a factor of several hundred using a pair of mirrors arranged in the Kirkpatrick-Baez (K-B) configuration. These are coated with multilayers to increase reflectivity and limit the pass band of the x-rays striking the sample. The x-rays excite characteristic fluorescent x-rays of elements in the sample, which are analyzed by an energy dispersive Si-Li detector, for a sensitive assay of the elemental content. By scanning the focal spot the spatial distribution of the elements is determined; the spatial resolution depends on the size of this spot. When spherical mirrors are used, the spatial resolution is limited by aberrations to 5 or 10 μm. This has been improved to 1 μm through the use of an elliptical mirror formed by elastically bending a plane mirror of uniform width and thickness with the optimum combination of end couples
Focusing X-rays to a 1-{mu}m spot using elastically bent, graded multilayer coated mirrors

Energy Technology Data Exchange (ETDEWEB)

Underwood, J.H.; Thompson, A.C.; Kortright, J.B. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

In the x-ray fluorescent microprobe at beamline 10.3.1, the ALS bending magnet source is demagnified by a factor of several hundred using a pair of mirrors arranged in the Kirkpatrick-Baez (K-B) configuration. These are coated with multilayers to increase reflectivity and limit the pass band of the x-rays striking the sample. The x-rays excite characteristic fluorescent x-rays of elements in the sample, which are analyzed by an energy dispersive Si-Li detector, for a sensitive assay of the elemental content. By scanning the focal spot the spatial distribution of the elements is determined; the spatial resolution depends on the size of this spot. When spherical mirrors are used, the spatial resolution is limited by aberrations to 5 or 10 {mu}m. This has been improved to 1 {mu}m through the use of an elliptical mirror formed by elastically bending a plane mirror of uniform width and thickness with the optimum combination of end couples.
Calibration and standards beamline 6.3.2 at the Advanced Light Source

International Nuclear Information System (INIS)

Underwood, J.H.; Gullikson, E.M.; Koike, M.; Batson, P.J.; Denham, P.E.; Franck, K.D.; Tackaberry, R.E.; Steele, W.F.

1996-01-01

This bending magnet beamline has been in operation since February 1995 for the characterization of optical elements (mirrors, gratings, multilayers, detectors, etc.) in the energy range 50 endash 1000 eV. Although it was designed primarily for precision reflectometry of multilayer reflecting optics for EUV projection lithography, it has capabilities for a wide range of measurements. The optics consist of a monochromator, a reflectometer, and refocusing mirrors to provide a small spot on the sample. The monochromator is a very compact, entrance-slitless, varied-line-spacing plane-grating design in which the mechanically ruled grating operates in the converging light from a spherical mirror working at high demagnification. Aberrations of the mirror are corrected by the line spacing variation, so that the spectral resolving power λ/Δλ is limited by the ALS source size to about 7000. Wavelength is scanned by simple rotation of the grating with a fixed exit slit. The reflectometer has the capability of positioning the sample to within 10 μm and setting its angular position to 0.002 degree. LABVIEW TM based software provides a convenient interface to the user. The reflectometer is separated from the beamline by a differential pump and can be pumped down in 1/2 hour. Auxiliary experimental stations can be mounted behind the reflectometer. Results are shown that demonstrate the performance and operational convenience of the beamline copyright 1996 American Institute of Physics
Study of the parabolic-spherical shape on the energy resolution in gamma spectrometry

International Nuclear Information System (INIS)

Silva, Joao Carlos Pereira da

1997-01-01

In gamma spectrometry, the energy resolution is an important parameter. This parameter measures the capability of the system to separate two photopeaks that are together. Scintillation systems have various factors that affect the energy resolution: energy deposition, light emission, light collection and electric signal processing. Light collection depended on the mechanisms of light transport until light strikes on the photocathode. In this trajectory the light losses energy by attenuation and refractions on the surfaces. In order to minimize these effects, a parabolic-spherical shape is proposed. The energy resolutions of hemispherical and parabolic-spherical shapes were measured. The results show a better resolution for the new shape, about 33% for Compton edge due to a 137 Cs radioactive source. (author)
Bound States in the Mirror TBA

NARCIS (Netherlands)

Arutyunov, G.E.; Frolov, S.; van Tongeren, S.J.

2012-01-01

The spectrum of the light-cone AdS_5 \\times S^5 superstring contains states composed of particles with complex momenta including in particular those which turn into bound states in the decompactification limit. We propose the mirror TBA description for these states. We focus on a three-particle
Transparent Electrochemical Gratings from a Patterned Bistable Silver Mirror.

Science.gov (United States)

Park, Chihyun; Na, Jongbeom; Han, Minsu; Kim, Eunkyoung

2017-07-25

Silver mirror patterns were formed reversibly on a polystyrene (PS)-patterned electrode to produce gratings through the electrochemical reduction of silver ions. The electrochemical gratings exhibited high transparency (T > 95%), similar to a see-through window, by matching the refractive index of the grating pattern with the surrounding medium. The gratings switch to a diffractive state upon the formation of a mirror pattern (T modulation, NIR light reflection, and on-demand heat transfer.
Preparation of spherical particles by vibrating orifice technique

Science.gov (United States)

Shibata, Shuichi; Tomizawa, Atsushi; Yoshikawa, Hidemi; Yano, Tetsuji; Yamane, Masayuki

2000-05-01

Preparation of micrometer-sized spherical particles containing Rhodamine 6G (R6G) has been investigated for the spherical cavity micro-laser. Using phenyl triethoxy silane (PTES) as a starting material, R6G-doped monodisperse spherical particles were prepared by the vibrating orifice technique. Processing consists of two major processes: (1) Hydrolysis and polymerization of PTES and (2) Droplet formation from PTES oligomers by vibrating orifice technique. A cylindrical liquid jet passing through the orifice of 10 and 20 micrometers in diameter breaks up into equal- sized droplets by mechanical vibration. Alcohol solvent of these droplets was evaporated during flying with carrier gas and subsequently solidified in ammonium water trap. For making smooth surface and god shaped particles, control of molecular weight of PTES oligomer was essential. R6G-doped hybrid spherical particles of 4 to 10 micrometers size of cavity structure were successfully obtained. The spherical particles were pumped by a second harmonic pulse of Q- switched Nd:YAG laser and laser emission peaks were observed at wavelengths which correspond to the resonance modes.
A low cost, light weight cenosphere–aluminium composite for brake ...

Indian Academy of Sciences (India)

. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 1. A low cost, light weight cenosphere–aluminium composite for brake disc application. V Saravanan P R Thyla S R Balakrishnan. Volume 39 Issue 1 February 2016 pp 299-305 ...
Classical transport in field reversed mirrors: reactor implications

International Nuclear Information System (INIS)

Auerbach, S.P.; Condit, W.C.

1980-01-01

Assuming that the field-reversed mirror (or the closely related spheromak) turns out to be stable, the next crucial issue is transport of particles and heat. Of particular concern is the field null on axis (the X-point), which at first glance seems to allow particles to flow out unhindered. We have evaluated the classical diffusion coefficients for particles and heat in field-reversed mirrors, with particular reference to a class of Hill's vortex models. Two fairly surprising results emerge from this study. First, the diffusion-driven flow of particles and heat is finite at the X-points. This may be traced to the geometrical constraint that the current (and hence the ion-electron drag force, which causes cross-field transport) must vanish on axis. This conclusion holds for any transport model. Second, the classical diffusion coefficient D(psi), which governs both particle and heat flux, is finite on the separatrix. Indeed, in a wide class of Hill's vortex equilibria (spherical, oblate, or prolate) D(psi) is essentially independent of psi (except for the usual factor of n
Light-weight extension tubes for compressed-air garden sprayers

Science.gov (United States)

Thomas W. McConkey; Charles E. Swett

1967-01-01

To hand-spray taller trees safely and efficiently, 8-, 12-, and 16-foot extension tubes for compressed-air garden sprayers were designed and built. These light-weight tubes have been used successfully for spraying white pine leaders for weevil control on the Massabesic Experimental Forest in Maine. Bill of materials and assembly instructions are included.
Light-weight Mutual Authentication with Non-repudiation

Directory of Open Access Journals (Sweden)

V. Clupek

2018-04-01

Full Text Available In this paper, we focused on a problem of authentication on low-cost devices. We have proposed a new light-weight protocol for mutual authentication of communication entities with non-repudiation of realized events. The protocol is simple and suitable for implementation on low-cost devices. Non-repudiation of realized events is achieved by involving a Trusted Third Party (TTP to the communication. The proposed protocol uses only an appropriate lightweight hash function and pre-shared secret data. Security of the proposed protocol was verified by the BAN (Burrows-Abadi-Needham logic.
Nanostructure Secondary-Mirror Apodizing Mask for Transmitter Signal Suppression in a Duplex Telescope

Science.gov (United States)

Hagopian, John; Livas, Jeffrey; Shiri, Shahram; Getty, Stephanie; Tveekrem, June; Butler, James

2012-01-01

A document discusses a nanostructure apodizing mask, made of multi-walled carbon nanotubes, that is applied to the centers (or in and around the holes) of the secondary mirrors of telescopes that are used to interferometrically measure the strain of space-time in response to gravitational waves. The shape of this ultra-black mask can be adjusted to provide a smooth transition to the clear aperture of the secondary mirror to minimize diffracted light. Carbon nanotubes grown on silicon are a viable telescope mirror substrate, and can absorb significantly more light than other black treatments. The hemispherical reflectance of multi-walled carbon nanotubes grown at GSFC is approximately 3 to 10 times better than a standard aerospace paint used for stray light control. At the LISA (Laser Interferometer Space Antenna) wavelength of 1 micron, the advantage over paint is a factor of 10. Primarily, in the center of the secondary mirror (in the region of central obscuration, where no received light is lost) a black mask is applied to absorb transmitted light that could be reflected back into the receiver. In the LISA telescope, this is in the center couple of millimeters. The shape of this absorber is critical to suppress diffraction at the edge. By using the correct shape, the stray light can be reduced by approximately 10 to the 9 orders of magnitude versus no center mask. The effect of the nanotubes has been simulated in a stray-light model. The effect of the apodizing mask has been simulated in a near-field diffraction model. Specifications are geometry-dependent, but the baseline design for the LISA telescope has been modeled as well. The coatings are somewhat fragile, but work is continuing to enhance adhesion.
COMPASS mirror wall of RICH 1

CERN Multimedia

Patrice Loïez

2001-01-01

The COMPASS experiment uses ring imaging Cherenkov (RICH) counters to identify particles produced in high-energy muon collisions, to better understand the spin structure of the nucleon. Charged particles moving faster than the speed of light in the medium through which they are travelling emit a cone of Cherenkov radiation in the direction of their motion. The light in this cone is reflected from these mirrors onto a photo detector so that the size of the cone can be measured, which gives the energy of the particle.
The Square Light Clock and Special Relativity

Science.gov (United States)

Galli, J. Ronald; Amiri, Farhang

2012-01-01

A thought experiment that includes a square light clock is similar to the traditional vertical light beam and mirror clock, except it is made up of four mirrors placed at a 45[degree] angle at each corner of a square of length L[subscript 0], shown in Fig. 1. Here we have shown the events as measured in the rest frame of the square light clock. By…
Stress intensity factors for complete internal and external cracks in spherical shells

International Nuclear Information System (INIS)

Chao, Y.J.; Chen, H.

1989-01-01

Cracks or flows found in the nuclear structure must be fully evaluated to assure the safety of the plant. The weight function method has been widely used in the determination of stress intensity factors for cracks under stress gradient e.g. for thermal shock loading. The unique features of the weight function method is that once the weight function for a particular cracked geometry is determined the stress intensity factors at the crack tip for any loading applied to the flawed structure can be calculated by a simple integration. In this paper the stress intensity factors of the complete, part-through internal and external cracks in a spherical shell are determined. The finite element method was used to develop the weight functions for the flawed geometry. The approximate crack surface profile was used to derive the weight functions. The stress intensity factors associated with the cracks in spherical shells under internal pressure are determined by both the weight functions and the direct finite element method
Polarization and reflectivity changes on mirror based viewing systems during long pulse operation

Energy Technology Data Exchange (ETDEWEB)

Malaquias, A. [Association-Euratom/IST, Instituto Superior Tecnico, Lisboa (Portugal); Von Hellermann, M. [Association-Euratom-FOM, Institute for Plasma Physique Rijnhuizen (Netherlands); Lotte, P. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Tugarinov, S. [SRC Triniti, Troitsk (Russian Federation); Voitsenya, V.S. [Institute of Plasma Physics of the National Science Center, Kharkov Institute of Physics and Technology (Ukraine)

2003-07-01

In ITER, long plasma discharges will produce a high flux of energetic particles leading to high erosion rate, as a consequence materials from first wall and divertor i.e. Be and C (or eventually W) will be released and will pile up on slightly-buried surfaces. Particularly affected by this scenario are MSE (motional Stark effect) diagnostic first mirrors. In this work the change in the polarization state of incident light induced by Be and C deposition on Au mirror is calculated. The results show that Be and C deposition on Au mirror will induce changes on light polarization and reflectivity properties as a function of layer thickness. For Be case, all the induced effects are seem to stabilize above 75 nm. This result indicates that the otherwise Au mirror becomes a Be mirror suggesting that the use of Be mirror as first mirror may help to diminish the transitional optical changes from Au to Be. For the case of C deposit, the results show that the polarization induced changes and intensity modulation (interference) are quite marked and much more visible than in the case of Be. In that sense, machines using C components will produce a more undesirable mirror deposit than a BPX with a Be first wall, although, they take advantage of a lower deposition rate. We have no data on Be or C deposition rate for ITER yet, but for the ITER MSE case, control and monitoring of the mirror state shall be included in the optical design. Uncertainties on measuring the polarization angle can be translated on the achievable spatial resolution.
Polarization and reflectivity changes on mirror based viewing systems during long pulse operation

International Nuclear Information System (INIS)

Malaquias, A.; Von Hellermann, M.; Lotte, P.; Voitsenya, V.S.

2003-01-01

In ITER, long plasma discharges will produce a high flux of energetic particles leading to high erosion rate, as a consequence materials from first wall and divertor i.e. Be and C (or eventually W) will be released and will pile up on slightly-buried surfaces. Particularly affected by this scenario are MSE (motional Stark effect) diagnostic first mirrors. In this work the change in the polarization state of incident light induced by Be and C deposition on Au mirror is calculated. The results show that Be and C deposition on Au mirror will induce changes on light polarization and reflectivity properties as a function of layer thickness. For Be case, all the induced effects are seem to stabilize above 75 nm. This result indicates that the otherwise Au mirror becomes a Be mirror suggesting that the use of Be mirror as first mirror may help to diminish the transitional optical changes from Au to Be. For the case of C deposit, the results show that the polarization induced changes and intensity modulation (interference) are quite marked and much more visible than in the case of Be. In that sense, machines using C components will produce a more undesirable mirror deposit than a BPX with a Be first wall, although, they take advantage of a lower deposition rate. We have no data on Be or C deposition rate for ITER yet, but for the ITER MSE case, control and monitoring of the mirror state shall be included in the optical design. Uncertainties on measuring the polarization angle can be translated on the achievable spatial resolution
Reference design for the standard mirror hybrid reactor

Energy Technology Data Exchange (ETDEWEB)

Bender, D.J.; Fink, J.H.; Galloway, T.R.; Kastenberg, W.E.; Lee, J.D.; Devoto, R.S.; Neef, W.S. Jr.; Schultz, K.R.; Culver, D.W.; Rao, S.B.; Rao, S.R.

1978-05-22

This report describes the results of a two-year study by Lawrence Livermore Laboratory and General Atomic Co. to develop a conceptual design for the standard (minimum-B) mirror hybrid reactor. The reactor parameters have been chosen to minimize the cost of producing nuclear fuel (/sup 239/Pu) for consumption in fission power reactors (light water reactors). The deuterium-tritium plasma produces approximately 400 MW of fusion power with a plasma Q of 0.64. The fast-fission blanket, which is fueled with depleted uranium and lithium, generates sufficient tritium to run the reactor, has a blanket energy multiplication of M = 10.4, and has a net fissile breeding ratio of Pu/n = 1.51. The reactor has a net electrical output of 600 MWe, a fissile production of 2000 kg of plutonium per year (at a capacity factor of 0.74), and a net plant efficiency of 0.18. The plasma-containment field is generated by a Yin-Yang magnet using NbTi superconductor, and the neutral beam system uses positive-ion acceleration with beam direct conversion. The spherical blanket is based on gas-cooled fast reactor technology. The fusion components, blanket, and primary heat-transfer loop components are all contained within a prestressed-concrete reactor vessel, which provides magnet restraint and supports the primary heat-transfer loop and the blanket.
Reference design for the standard mirror hybrid reactor

International Nuclear Information System (INIS)

Bender, D.J.; Fink, J.H.; Galloway, T.R.; Kastenberg, W.E.; Lee, J.D.; Devoto, R.S.; Neef, W.S. Jr.; Schultz, K.R.; Culver, D.W.; Rao, S.B.; Rao, S.R.

1978-01-01

This report describes the results of a two-year study by Lawrence Livermore Laboratory and General Atomic Co. to develop a conceptual design for the standard (minimum-B) mirror hybrid reactor. The reactor parameters have been chosen to minimize the cost of producing nuclear fuel ( 239 Pu) for consumption in fission power reactors (light water reactors). The deuterium-tritium plasma produces approximately 400 MW of fusion power with a plasma Q of 0.64. The fast-fission blanket, which is fueled with depleted uranium and lithium, generates sufficient tritium to run the reactor, has a blanket energy multiplication of M = 10.4, and has a net fissile breeding ratio of Pu/n = 1.51. The reactor has a net electrical output of 600 MWe, a fissile production of 2000 kg of plutonium per year (at a capacity factor of 0.74), and a net plant efficiency of 0.18. The plasma-containment field is generated by a Yin-Yang magnet using NbTi superconductor, and the neutral beam system uses positive-ion acceleration with beam direct conversion. The spherical blanket is based on gas-cooled fast reactor technology. The fusion components, blanket, and primary heat-transfer loop components are all contained within a prestressed-concrete reactor vessel, which provides magnet restraint and supports the primary heat-transfer loop and the blanket

Moderate Versus Light Pressure Massage Therapy Leads to Greater Weight Gain in Preterm Infants

Science.gov (United States)

Field, Tiffany; Diego, Miguel A.; Hernandez-Reif, Maria; Deeds, Osvelia; Figuereido, Barbara

2007-01-01

Sixty-eight preterm infants (M GA=3Owks.) were randomly assigned to a moderate or to a light pressure massage therapy group to receive 15 massages 3 times per day for 5 days. Behavior state, stress behaviors and heart rate were recorded for 15 minutes before and during the first 15-minute therapy session. Weight gain was recorded over the 5 day therapy period. The moderate versus light pressure massage group gained significantly more weight per day. During the behavior observations the moderate versus light pressure massage group showed significantly lower increases from the pre-session to the session recording on: 1) active sleep; 2) fussing; 3) crying; 4) movement; and 5) stress behavior (hiccupping). They also showed a smaller decrease in deep sleep, a greater decrease in heart rate and a greater increase in vagal tone. Thus, the moderate pressure massage therapy group appeared to be more relaxed and less aroused than the light pressure massage group which may have contributed to the greater weight gain of the moderate pressure massage therapy group. PMID:17138310
Mirror fusion reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Moir, R.W.

1978-01-01

We have carried out conceptual design studies of fusion reactors based on the three current mirror confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fission fuel for fission reactors. We have designed a large commercial hybrid based on standard mirror confinement, and also a small pilot plant hybrid. Tandem mirror designs include a commercial 1000 MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single cell pilot plant
Mirror fusion reactors

International Nuclear Information System (INIS)

Anon.

1978-01-01

Conceptual design studies were made of fusion reactors based on the three current mirror-confinement concepts: the standard mirror, the tandem mirror, and the field-reversed mirror. Recent studies of the standard mirror have emphasized its potential as a fusion-fission hybrid reactor, designed to produce fuel for fission reactors. We have designed a large commercial hybrid and a small pilot-plant hybrid based on standard mirror confinement. Tandem mirror designs include a commercial 1000-MWe fusion power plant and a nearer term tandem mirror hybrid. Field-reversed mirror designs include a multicell commercial reactor producing 75 MWe and a single-cell pilot plant
Phase correction for a Michelson interferometer with misaligned mirrors

Science.gov (United States)

Goorvitch, D.

1975-01-01

The phase correction for a Michelson interferometer with misaligned mirrors in converging light is shown to give rise to a quadratic phase shift. In general, the calculation of a spectrum from the measured interferogram needs phase correction. Phase corrections have been well worked out for the cases of a linear phase shift and a phase that is slowly varying. The standard procedures for correcting calculated spectra need to be modified, however, to remove any phase errors resulting from misaligned mirrors.
Chiral mirrors

International Nuclear Information System (INIS)

Plum, Eric; Zheludev, Nikolay I.

2015-01-01

Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media
Mirror agnosia and the mirrored-self misidentification delusion: a hypnotic analogue.

Science.gov (United States)

Connors, Michael H; Cox, Rochelle E; Barnier, Amanda J; Langdon, Robyn; Coltheart, Max

2012-05-01

Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion. Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry. Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger. Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants' expectations and interpretations, are discussed.
Examining the Effects of Chromatic Aberration, Object Distance, and Eye Shape on Image-Formation in the Mirror-Based Eyes of the Bay Scallop Argopecten irradians.

Science.gov (United States)

Speiser, Daniel I; Gagnon, Yakir Luc; Chhetri, Raghav K; Oldenburg, Amy L; Johnsen, Sönke

2016-11-01

The eyes of scallops form images using a concave spherical mirror and contain two separate retinas, one layered on top of the other. Behavioral and electrophysiological studies indicate that the images formed by these eyes have angular resolutions of about 2°. Based on previous ray-tracing models, it has been thought that the more distal of the two retinas lies near the focal point of the mirror and that the proximal retina, positioned closer to the mirror at the back of the eye, receives light that is out-of-focus. Here, we propose three mechanisms through which both retinas may receive focused light: (1) chromatic aberration produced by the lens may cause the focal points for longer and shorter wavelengths to fall near the distal and proximal retinas, respectively; (2) focused light from near and far objects may fall on the distal and proximal retinas, respectively; and (3) the eyes of scallops may be dynamic structures that change shape to determine which retina receives focused light. To test our hypotheses, we used optical coherence tomography (OCT), a method of near-infrared optical depth-ranging, to acquire virtual cross-sections of live, intact eyes from the bay scallop Argopecten irradians Next, we used a custom-built ray-tracing model to estimate the qualities of the images that fall on an eye's distal and proximal retinas as functions of the wavelengths of light entering the eye (400-700 nm), object distances (0.01-1 m), and the overall shape of the eye. When we assume 550 nm wavelength light and object distances greater than 0.01 m, our model predicts that the angular resolutions of the distal and proximal retinas are 2° and 7°, respectively. Our model also predicts that neither chromatic aberration nor differences in object distance lead to focused light falling on the distal and proximal retinas simultaneously. However, if scallops can manipulate the shapes of their eyes, perhaps through muscle contractions, we speculate that they may be able
Comprehensive Evaluation of Car-Body Light-Weighting Scheme Based on LCC Theory

Directory of Open Access Journals (Sweden)

Han Qing-lan

2016-01-01

Full Text Available In this paper, a comprehensive evaluation model of light-weighting scheme is established, which is based on three dimensions, including the life cycle costs of the resource consumed by the designed objects (LCC, willingness to pay for the environmental effect of resource consumption (WTP and performance (P. Firstly, cost of each stage is determined. Then, based on the resource classification, which is based on cost elements, determine the material list needed, and apply WTP weight coefficient to monetize life cycle environmental impact and obtain the life cycle comprehensive cost of designed scheme (TCC. In the next step Performance (P index is calculated to measure the value of the life cycle costs by applying AHP and SAW method, integrated (TCC and (P to achieve comprehensive evaluation of light-weighting scheme. Finally, the effectiveness of the evaluation model is verified by the example of car engine hood.
A light-weight hyperspectral mapping system for unmanned aerial vehicles - The first results

NARCIS (Netherlands)

Suomalainen, Juha; Anders, Niels; Iqbal, Shahzad; Franke, Jappe; Wenting, Philip; Bartholomeus, Harm; Becker, Rolf; Kooistra, Lammert

2017-01-01

Research opportunities using UAV remote sensing techniques are limited by the payload of the platform. Therefore small UAV's are typically not suitable for hyperspectral imaging due to the weight of the mapping system. In this research, we are developing a light-weight hyperspectral mapping system
Mirror profile optimization for nano-focusing KB mirror

International Nuclear Information System (INIS)

Zhang Lin; Baker, Robert; Barrett, Ray; Cloetens, Peter; Dabin, Yves

2010-01-01

A KB focusing mirror width profile has been optimized to achieve nano-focusing for the nano-imaging end-station ID22NI at the ESRF. The complete mirror and flexure bender assembly has been modeled in 3D with finite element analysis using ANSYS. Bender stiffness, anticlastic effects and geometrical non-linear effects have been considered. Various points have been studied: anisotropy and crystal orientation, stress in the mirror and bender, actuator resolution and the mirror-bender adhesive bonding... Extremely high performance of the mirror is expected with residual slope error smaller than 0.6 μrad, peak-to-valley, compared to the bent slope of 3000 μrad.
Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

Science.gov (United States)

Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey; Catmur, Caroline

2014-08-01

The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.
Integrated Design Optimization of a 5-DOF Assistive Light-weight Anthropomorphic Arm

DEFF Research Database (Denmark)

Zhou, Lelai; Bai, Shaoping; Hansen, Michael Rygaard

2011-01-01

An integrated dimensional and drive train optimization method was developed for light-weight robotic arm design. The method deals with the determination of optimal link lengths and the optimal selection of motors and gearboxes from commercially available components. Constraints are formulated...... on the basis of kinematic performance and dynamic requirements, whereas the main objective is to minimize the weight. The design of a human-like arm, which is 10 kg in weight with a load capacity of 5 kg, is described....
Ultra light weight jet engine JR100; Chokeiryo jet engine JR100

Energy Technology Data Exchange (ETDEWEB)

Matsuki, M. [Nippon Institute of Technology, Saitama (Japan)

1999-03-20

As a part of the jet lift V/STOL research by National Aerospace Laboratory, a study of trial manufacture of ultra light weight jet engine JR 100 started in FY 1964. The study was aimed at obtaining a lift engine for VTOL and founding the base for the future jet lift VTOL, and at taking in the results of the jet engine element study accumulated so far and manufacturing an advanced engine. Decided on the use of domestic materials for JR 100, the materials to be used are almost iron-based ones. Through the efforts for weight reduction in structure and processing, a thrust/weight ratio of 10 was realized. At the same time, the production/processing of light weight materials such as titanium alloys was proceeded with, and by adopting the materials to JR 200 system, a thrust/weight ratio of 15 was realized. Together with these, for the purpose of reducing the fuel consumption rate, studies started on fan for lift fan engine and high temperature turbine (an inlet temperature of 1250 degrees C was achieved), to get low noise/high efficiency fan. By the research results, the basis for jet lift VTOL was established, and it became the basis for the development of turbo fan engine FJR 710. (NEDO)
Superconducting (radiation hardened) magnets for mirror fusion devices

International Nuclear Information System (INIS)

Henning, C.D.; Dalder, E.N.C.; Miller, J.R.; Perkins, J.R.

1983-01-01

Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10 10 to 10 11 rads, while magnet stability must be retained after the copper has been exposed to fluence above 10 19 neutrons/cm 2
Ultrasoft x-ray imaging system for the National Spherical Torus Experiment

Science.gov (United States)

Stutman, D.; Finkenthal, M.; Soukhanovskii, V.; May, M. J.; Moos, H. W.; Kaita, R.

1999-01-01

A spectrally resolved ultrasoft x-ray imaging system, consisting of arrays of high resolution (the National Spherical Torus Experiment. Initially, three poloidal arrays of diodes filtered for C 1s-np emission will be implemented for fast tomographic imaging of the colder start-up plasmas. Later on, mirrors tuned to the C Lyα emission will be added in order to enable the arrays to "see" the periphery through the hot core and to study magnetohydrodynamic activity and impurity transport in this region. We also discuss possible core diagnostics, based on tomographic imaging of the Lyα emission from the plume of recombined, low Z impurity ions left by neutral beams or fueling pellets. The arrays can also be used for radiated power measurements and to map the distribution of high Z impurities injected for transport studies. The performance of the proposed system is illustrated with results from test channels on the CDX-U spherical torus at Princeton Plasma Physics Laboratory.
A magic mirror - quantum applications of the optical beam splitter

International Nuclear Information System (INIS)

Bachor, H.A.

2000-01-01

Mirrors are some of the simplest optical components, and their use in optical imaging is well known. They have many other applications, such as the control of laser beams or in optical communication. Indeed they can be found in most optical instruments. It is the partially reflecting mirror, better known as the beam splitter, that is of particular interest to us. It lies at the centre of a number of recent scientific discoveries and technical developments that go beyond the limits of classical optics and make use of the quantum properties of light. In this area Australian and New Zealand researchers have made major contributions in the last two decades. In this paper, the author discusses how a mirror modifies the light itself and the information that can be sent by a beam, and summarise the recent scientific achievements. It combines the idea of photons, where the idea of quantisation is immediately obvious, with the idea of modulating continuous laser beams, which is practical and similar to the engineering description of radio communication
Refractive optics to compensate x-ray mirror shape-errors

Science.gov (United States)

Laundy, David; Sawhney, Kawal; Dhamgaye, Vishal; Pape, Ian

2017-08-01

Elliptically profiled mirrors operating at glancing angle are frequently used at X-ray synchrotron sources to focus X-rays into sub-micrometer sized spots. Mirror figure error, defined as the height difference function between the actual mirror surface and the ideal elliptical profile, causes a perturbation of the X-ray wavefront for X- rays reflecting from the mirror. This perturbation, when propagated to the focal plane results in an increase in the size of the focused beam. At Diamond Light Source we are developing refractive optics that can be used to locally cancel out the wavefront distortion caused by figure error from nano-focusing elliptical mirrors. These optics could be used to correct existing optical components on synchrotron radiation beamlines in order to give focused X-ray beam sizes approaching the theoretical diffraction limit. We present our latest results showing measurement of the X-ray wavefront error after reflection from X-ray mirrors and the translation of the measured wavefront into a design for refractive optical elements for correction of the X-ray wavefront. We show measurement of the focused beam with and without the corrective optics inserted showing reduction in the size of the focus resulting from the correction to the wavefront.
Mechanism design of the Thomson scattering diagnostic system for the TMX east mirror plug

International Nuclear Information System (INIS)

Lang, D.D.; Goodman, R.K.; Jenkins, S.L.; Wilkerson, J.A.; Parkinson, J.L.

1979-01-01

This Thomson scattering diagnostic system is used to measure the electron temperature and density of the east mirror plug of the Tandem Mirror Experiment (TMX) at Lawrence Livermore Laboratory. The measurements are made by firing a high-power ruby laser pulse through the plasma where the electrons then re-radiate a small fraction of the light. Because of the velocity of the electrons, the wavelength of the re-radiated light is Doppler shifted. The width of the Doppler-shifted wavelength spectrum is a measure of the temperature of the electrons in the plasma, and the total amount of re-radiated light is proportional to the electron density
Analytic theory of the spherical electron to ion convertor

International Nuclear Information System (INIS)

Verdeyen, J.T.; Miller, P.A.

1980-01-01

Calculations will be presented which indicate that one could, with high efficiency, convert the electron beam energy transported from many pinched diode to ions at a reasonably sized evacuated spherical shell - or a light bulb
Bimorph mirrors: The Good, the Bad, and the Ugly

Science.gov (United States)

Alcock, Simon G.; Sutter, John P.; Sawhney, Kawal J. S.; Hall, David R.; McAuley, Katherine; Sorensen, Thomas

2013-05-01

Bimorph mirrors are widely used by the X-ray, Laser, Space, and Astronomy communities to focus or collimate photon beams. Applying voltages to the embedded piezo ceramics enables the user to globally bend the optical substrate to a range of figures (including cylindrical, parabolic, and elliptical), and finely correct low spatial frequency errors, thus improving optical performance. Bimorph mirrors are employed on numerous synchrotron X-ray beamlines, including several at Diamond Light Source. However, many such beamlines were not achieving the desired size and shape of the reflected X-ray beam. Metrology data from ex-situ, slope measuring profilometry (using the Diamond-NOM) and in-situ, synchrotron X-ray "pencil-beam" scans, revealed sharp defects on the optical substrate directly above the locations at which the piezo ceramics are bonded together. This so-called "junction effect" has been observed on a variety of bimorph mirrors with different numbers of piezos, substrate length, and thickness. To repair this damage, three pairs of bimorph mirrors were re-polished at Thales-SESO. We review the re-polishing process, and show that it successfully removed the junction effect, and significantly improved beamline performance. Since the internal structure of the bimorph mirrors was not modified during re-polishing, it is hoped that the mirrors will retain their surface quality, and remain operational for many years. We also highlight the combination of super-polishing techniques with bimorph technology to create the "Ultimate" mirror, and discuss a next generation, bimorph mirror which is predicted not to suffer from the junction effect.

Bimorph mirrors: The Good, the Bad, and the Ugly

International Nuclear Information System (INIS)

Alcock, Simon G.; Sutter, John P.; Sawhney, Kawal J.S.; Hall, David R.; McAuley, Katherine; Sorensen, Thomas

2013-01-01

Bimorph mirrors are widely used by the X-ray, Laser, Space, and Astronomy communities to focus or collimate photon beams. Applying voltages to the embedded piezo ceramics enables the user to globally bend the optical substrate to a range of figures (including cylindrical, parabolic, and elliptical), and finely correct low spatial frequency errors, thus improving optical performance. Bimorph mirrors are employed on numerous synchrotron X-ray beamlines, including several at Diamond Light Source. However, many such beamlines were not achieving the desired size and shape of the reflected X-ray beam. Metrology data from ex-situ, slope measuring profilometry (using the Diamond-NOM) and in-situ, synchrotron X-ray “pencil-beam” scans, revealed sharp defects on the optical substrate directly above the locations at which the piezo ceramics are bonded together. This so-called “junction effect” has been observed on a variety of bimorph mirrors with different numbers of piezos, substrate length, and thickness. To repair this damage, three pairs of bimorph mirrors were re-polished at Thales-SESO. We review the re-polishing process, and show that it successfully removed the junction effect, and significantly improved beamline performance. Since the internal structure of the bimorph mirrors was not modified during re-polishing, it is hoped that the mirrors will retain their surface quality, and remain operational for many years. We also highlight the combination of super-polishing techniques with bimorph technology to create the “Ultimate” mirror, and discuss a next generation, bimorph mirror which is predicted not to suffer from the junction effect
Method of preparing light-weight plugging mud

Energy Technology Data Exchange (ETDEWEB)

Gorskiy, V F; Melnichuk, A N; Vernikovskiy, A N

1982-01-01

A method is proposed for preparing a light-weight plugging mud which includes mixing Portland cement on an aqueous suspension of palygorskite. It is distinguished by the fact that in order to improve the quality of the mud and strength of the cement stone with simultaneous decrease in the gas permeability, before mixing the Portland cement, the aqueous suspension of palygorskite is dispersed to stabilization of viscosity, and after mixing the Portland cement, the obtained cement-clay mixture is exposed to additional dispersion under pressure. The ratio of the ingredients is the following (% by mass): Portland cement 32.0-61.0; palygorskite 1.2-2.9; water--the rest.
Modeling of biaxial gimbal-less MEMS scanning mirrors

Science.gov (United States)

von Wantoch, Thomas; Gu-Stoppel, Shanshan; Senger, Frank; Mallas, Christian; Hofmann, Ulrich; Meurer, Thomas; Benecke, Wolfgang

2016-03-01

One- and two-dimensional MEMS scanning mirrors for resonant or quasi-stationary beam deflection are primarily known as tiny micromirror devices with aperture sizes up to a few Millimeters and usually address low power applications in high volume markets, e.g. laser beam scanning pico-projectors or gesture recognition systems. In contrast, recently reported vacuum packaged MEMS scanners feature mirror diameters up to 20 mm and integrated high-reflectivity dielectric coatings. These mirrors enable MEMS based scanning for applications that require large apertures due to optical constraints like 3D sensing or microscopy as well as for high power laser applications like laser phosphor displays, automotive lighting and displays, 3D printing and general laser material processing. This work presents modelling, control design and experimental characterization of gimbal-less MEMS mirrors with large aperture size. As an example a resonant biaxial Quadpod scanner with 7 mm mirror diameter and four integrated PZT (lead zirconate titanate) actuators is analyzed. The finite element method (FEM) model developed and computed in COMSOL Multiphysics is used for calculating the eigenmodes of the mirror as well as for extracting a high order (n system inputs and scanner displacement as system output. By applying model order reduction techniques using MATLABR a compact state space system approximation of order n = 6 is computed. Based on this reduced order model feedforward control inputs for different, properly chosen scanner displacement trajectories are derived and tested using the original FEM model as well as the micromirror.
A study of different types of current mirrors using polysilicon TFTs

International Nuclear Information System (INIS)

Pappas, I; Nalpantidis, L; Kalenteridis, V; Siskos, S; Dimitriadis, C A; Hatzopoulos, A A

2005-01-01

Polysilicon thin-film technology has become of great interest due to the demand for large area electronic devices. Active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting displays (AMOLEDs) are among the fields where polysilicon thin-film transistors (poly-Si TFTs) are most commonly used. Such devices, generally, require analog signal processing. This fact makes the performance of basic analog blocks, such as current mirrors implemented with poly-Si TFTs, crucial. This paper examines the performance of various current mirror designs through simulation. Finally, a novel design of a current mirror is proposed aimed to be used in low voltage applications
Beating quantum limits in interferometers with quantum locking of mirrors

International Nuclear Information System (INIS)

Heidmann, Antoine; Courty, Jean-Michel; Pinard, Michel; Lebars, Julien

2004-01-01

The sensitivity in interferometric measurements such as those made by gravitational-wave detectors is ultimately limited by the quantum noise of light. We discuss the use of feedback mechanisms to reduce the quantum effects of radiation pressure. Recent experiments have shown that it is possible to reduce the thermal motion of a mirror by cold damping. The mirror motion is measured with an optomechanical sensor based on a high-finesse cavity, and reduced by a feedback loop. We show that this technique can be extended to lock the mirror at the quantum level. In gravitational-wave interferometers with Fabry-Perot cavities in each arm, it is even possible to use a single feedback mechanism to lock one cavity mirror on the other. This quantum locking greatly improves the sensitivity of the interferometric measurement. It is furthermore insensitive to imperfections such as losses in the interferometer
Flux-redistribution in the focal region of a planar Fresnel ring mirror

Energy Technology Data Exchange (ETDEWEB)

Sastroamidjojo, M.S.A. (Gadjah Mada Univ., Indonesia); Lubis, W.

1979-01-01

The results of an investigation of flux redistribution at the focal region of a planar Fresnel ring mirror are reported. A parabolic mirror of large aperture was used to provide a parallel beam of light which was directed at the Fresnel test object. A cotton thread grid was used as a mapping aid to provide a 25 x 25 matrix of spatial data points. (SPH)
An Evaluation of the Instruction Carried out with Printed Laboratory Materials Designed in Accordance with 5E Model: Reflection of Light and Image on a Plane Mirror

Science.gov (United States)

Ayvaci, Hakan Sevki; Yildiz, Mehmet; Bakirci, Hasan

2015-01-01

This study employed a print laboratory material based on 5E model of constructivist learning approach to teach reflection of light and Image on a Plane Mirror. The effect of the instruction which conducted with the designed print laboratory material on academic achievements of prospective science and technology teachers and their attitudes towards…
Light-weight reference-based compression of FASTQ data.

Science.gov (United States)

Zhang, Yongpeng; Li, Linsen; Yang, Yanli; Yang, Xiao; He, Shan; Zhu, Zexuan

2015-06-09

The exponential growth of next generation sequencing (NGS) data has posed big challenges to data storage, management and archive. Data compression is one of the effective solutions, where reference-based compression strategies can typically achieve superior compression ratios compared to the ones not relying on any reference. This paper presents a lossless light-weight reference-based compression algorithm namely LW-FQZip to compress FASTQ data. The three components of any given input, i.e., metadata, short reads and quality score strings, are first parsed into three data streams in which the redundancy information are identified and eliminated independently. Particularly, well-designed incremental and run-length-limited encoding schemes are utilized to compress the metadata and quality score streams, respectively. To handle the short reads, LW-FQZip uses a novel light-weight mapping model to fast map them against external reference sequence(s) and produce concise alignment results for storage. The three processed data streams are then packed together with some general purpose compression algorithms like LZMA. LW-FQZip was evaluated on eight real-world NGS data sets and achieved compression ratios in the range of 0.111-0.201. This is comparable or superior to other state-of-the-art lossless NGS data compression algorithms. LW-FQZip is a program that enables efficient lossless FASTQ data compression. It contributes to the state of art applications for NGS data storage and transmission. LW-FQZip is freely available online at: http://csse.szu.edu.cn/staff/zhuzx/LWFQZip.
Schroedinger’s Mirrors - exploring mechanical motion in the quantum regime

CERN Multimedia

CERN. Geneva

2017-01-01

The quantum optical control of solid-state mechanical devices, quantum optomechanics, has emerged as a new frontier of light-matter interactions. Devices currently under investigation cover a mass range of more than 17 orders of magnitude - from nanomechanical waveguides of some picograms to macroscopic, kilogram-weight mirrors of gravitational wave detectors. This development has been enabled by the insight that quantum optics provides a powerful toolbox to generate, manipulate and detect quantum states of mechanical motion, in particular by coupling the mechanics to an optical or microwave cavity field. Originally, such cavity optomechanical systems have been studied from the early 1970s on in the context of gravitational wave antennas. Advancements in micro-fabrication and micro-cavities, however, have resulted in the development of a completely new generation of nano- and micro-optomechanical devices. Today, 10 years after the first demonstrations of laser cooling of micromechanical resonators, the quantu...
DESIGN OF MIRRORS AND APODIZATION FUNCTIONS IN PHASE-INDUCED AMPLITUDE APODIZATION SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Cady, Eric, E-mail: eric.j.cady@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109 (United States)

2012-08-01

Phase-induced amplitude apodization (PIAA) coronagraphs are a promising technology for imaging exoplanets, with the potential to detect Earth-like planets around Sun-like stars. A PIAA system nominally consists of a pair of mirrors that reshape incident light without attenuation, coupled with one or more apodizers to mitigate diffraction effects or provide additional beam shaping to produce a desired output profile. We present a set of equations that allow apodizers to be chosen for any given pair of mirrors, or conversely mirror shapes chosen for given apodizers, to produce an arbitrary amplitude profile at the output of the system. We show how classical PIAA systems may be designed by this method and present the design of a novel four-mirror system with higher throughput than a standard two-mirror system. We also discuss the limitations due to diffraction and the design steps that may be taken to mitigate them.
Topological mirror superconductivity.

Science.gov (United States)

Zhang, Fan; Kane, C L; Mele, E J

2013-08-02

We demonstrate the existence of topological superconductors (SCs) protected by mirror and time-reversal symmetries. D-dimensional (D=1, 2, 3) crystalline SCs are characterized by 2(D-1) independent integer topological invariants, which take the form of mirror Berry phases. These invariants determine the distribution of Majorana modes on a mirror symmetric boundary. The parity of total mirror Berry phase is the Z(2) index of a class DIII SC, implying that a DIII topological SC with a mirror line must also be a topological mirror SC but not vice versa and that a DIII SC with a mirror plane is always time-reversal trivial but can be mirror topological. We introduce representative models and suggest experimental signatures in feasible systems. Advances in quantum computing, the case for nodal SCs, the case for class D, and topological SCs protected by rotational symmetries are pointed out.
General and smoking cessation weight concern in a Hispanic sample of light and intermittent smokers.

Science.gov (United States)

Landrau-Cribbs, Erica; Cabriales, José Alonso; Cooper, Theodore V

2015-02-01

This study assessed general and cessation related weight concerns in a Hispanic sample of light (≤10 cigarettes per day) and intermittent (non-daily smoking) smokers (LITS) participating in a brief smoking cessation intervention. Three hundred and fifty-four Hispanic LITS (Mage=34.2, SD=14; 51.1% male; 57.9% Mexican American; 59.0% daily light, 41.0% intermittent) completed baseline measures assessing demographics, tobacco use/history, stage of change (SOC), general weight concern, and cessation related weight concern. Three multiple logistic regression models examined potential predictors (i.e., age, gender, SOC, cigarettes per month, smoking status [daily vs non-daily], weight, cessation related weight concern, general weight concern) of general weight concern, cessation related weight concern, and past 30day abstinence (controlling for the intervention). Study results indicated that a majority of participants reported general weight concern (59.6%), and slightly more than a third (35.6%) reported post cessation weight gain concern (mean and median weight tolerated before relapse were within the 10-12lb range). Lower weight and endorsing general weight concern were associated with cessation related weight concern. Female gender, higher weight, and endorsing cessation related weight concern were associated with general weight concern. Monthly cigarette use was associated with smoking cessation at the three-month follow-up. The results indicate a substantial prevalence of general weight concern and non-trivial rates of cessation related weight concern in Hispanic LITS attempting to quit, and greater success in quitting among those who reported lower rates of cigarettes smoked per month. Copyright © 2014 Elsevier Ltd. All rights reserved.
Optimal micro-mirror tilt angle and sync mark design for digital micro-mirror device based collinear holographic data storage system.

Science.gov (United States)

Liu, Jinpeng; Horimai, Hideyoshi; Lin, Xiao; Liu, Jinyan; Huang, Yong; Tan, Xiaodi

2017-06-01

The collinear holographic data storage system (CHDSS) is a very promising storage system due to its large storage capacities and high transfer rates in the era of big data. The digital micro-mirror device (DMD) as a spatial light modulator is the key device of the CHDSS due to its high speed, high precision, and broadband working range. To improve the system stability and performance, an optimal micro-mirror tilt angle was theoretically calculated and experimentally confirmed by analyzing the relationship between the tilt angle of the micro-mirror on the DMD and the power profiles of diffraction patterns of the DMD at the Fourier plane. In addition, we proposed a novel chess board sync mark design in the data page to reduce the system bit error rate in circumstances of reduced aperture required to decrease noise and median exposure amount. It will provide practical guidance for future DMD based CHDSS development.
Tailored Buckling Microlattices as Reusable Light-Weight Shock Absorbers.

Science.gov (United States)

Frenzel, Tobias; Findeisen, Claudio; Kadic, Muamer; Gumbsch, Peter; Wegener, Martin

2016-07-01

Structures and materials absorbing mechanical (shock) energy commonly exploit either viscoelasticity or destructive modifications. Based on a class of uniaxial light-weight geometrically nonlinear mechanical microlattices and using buckling of inner elements, either a sequence of snap-ins followed by irreversible hysteretic - yet repeatable - self-recovery or multistability is achieved, enabling programmable behavior. Proof-of-principle experiments on three-dimensional polymer microstructures are presented. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Coherent, Short-Pulse X-ray Generation via Relativistic Flying Mirrors

Directory of Open Access Journals (Sweden)

Masaki Kando

2018-04-01

Full Text Available Coherent, Short X-ray pulses are demanded in material science and biology for the study of micro-structures. Currently, large-sized free-electron lasers are used; however, the available beam lines are limited because of the large construction cost. Here we review a novel method to downsize the system as well as providing fully (spatially and temporally coherent pulses. The method is based on the reflection of coherent laser light by a relativistically moving mirror (flying mirror. Due to the double Doppler effect, the reflected pulses are upshifted in frequency and compressed in time. Such mirrors are formed when an intense short laser pulse excites a strongly nonlinear plasma wave in tenuous plasma. Theory, proof-of-principle, experiments, and possible applications are addressed.
The ELT in 2017: The Year of the Primary Mirror

Science.gov (United States)

Cirasuolo, M.; Tamai, R.; Cayrel, M.; Koehler, B.; Biancat Marchet, F..; González, J. C.; Dimmler, M.; Tuti, M.; ELT Team

2018-03-01

The Extremely Large Telescope (ELT) is at the core of ESO's vision to deliver the largest optical and infrared telescope in the world. With its unrivalled sensitivity and angular resolution the ELT will transform our view of the Universe: from exoplanets to resolved stellar populations, from galaxy evolution to cosmology and fundamental physics. This article focuses on one of the most challenging aspects of the entire programme, the 39-metre primary mirror (M1). 2017 was a particularly intense year for M1, the main highlight being the approval by ESO's Council to proceed with construction of the entire mirror. In addition, several contracts have been placed to ensure that the giant primary mirror will be operational at first light.
Development and control of a three-axis satellite simulator for the bifocal relay mirror initiative

OpenAIRE

Chernesky, Vincent S.

2001-01-01

The Three Axis Satellite Simulator (TASS) is a 4-foot diameter octagonal platform supported on a spherical air bearing. The platform hosts several satellite subsystems, including rate gyros, reaction wheels, thrusters, sun sensors, and an onboard control computer. This free-floating design allows for realistic emulation of satellite attitude dynamics in a laboratory environment. The bifocal relay mirror spacecraft system is composed of two optically coupled telescopes used to redirect the las...
Prepulse suppression using a self-induced, ultrashort pulse plasma mirror

International Nuclear Information System (INIS)

Gold, D.M.; Nathel, H.; Bolton, P.R.; White, W.E.; Van Woerkom, L.D.

1991-01-01

The plasma mirror is a self-induced, plasm-based optical element which can be inserted into existing experiments to reduce repulse energy without significant degradation of ultrashort pulse laser light. The authors have characteristics of the reflected pulse. The initial measurements indicate that the incident pulse reflects specularly from a high density, highly reflective plasma. The reflected pulse has a smoothed spatial profile and reduced pulsewidth. This paper outlines future work to characterize both the plasm mirror technique of repulse suppression and its reflected pulse
Numerical evaluation of integrals containing a spherical Bessel function by product integration

International Nuclear Information System (INIS)

Lehman, D.R.; Parke, W.C.; Maximon, L.C.

1981-01-01

A method is developed for numerical evaluation of integrals with k-integration range from 0 to infinity that contain a spherical Bessel function j/sub l/(kr) explicitly. The required quadrature weights are easily calculated and the rate of convergence is rapid: only a relatively small number of quadrature points is needed: for an accurate evaluation even when r is large. The quadrature rule is obtained by the method of product integration. With the abscissas chosen to be those of Clenshaw--Curtis and the Chebyshev polynomials as the interpolating polynomials, quadrature weights are obtained that depend on the spherical Bessel function. An inhomogenous recurrence relation is derived from which the weights can be calculated without accumulation of roundoff error. The procedure is summarized as an easily implementable algorithm. Questions of convergence are discussed and the rate of convergence demonstrated for several test integrals. Alternative procedures are given for generating the integration weights and an error analysis of the method is presented
Wind induced fatigue of slender light weight structures in structural dynamics

NARCIS (Netherlands)

Staalduinen, P.C. van; Courage, W.M.G.

1996-01-01

The paper presents a simplified analytical method for calculating the stress ranges in light weight slender structures due to wind loading. The background and assumptions of the method have been explained as well as the derivation of the relevant formula. The application of the simplified method on

The use of light weight deflectometer for in situ evaluation of sand degree of compaction

Directory of Open Access Journals (Sweden)

Amr F. Elhakim

2014-12-01

Full Text Available The light weight deflectometer (LWD, also known as the light falling weight deflectometer, light drop weight tester, and dynamic plate load test, is a hand portable device that was developed in Germany to measure the soil in situ LWD dynamic modulus. Typically, this modulus is used to evaluate the subsoil degree of compaction. Thus it is suitable for compaction quality control of soil-surfaced roads, embankments and replacement fill. As a dynamic test, the device is suited, in particular, for coarse and mixed grained soils with a maximum grain size of 63 mm. The response of poorly graded calcareous and siliceous sands is the focus of this research. First, the index soil properties of the tested soils including grain size distribution; maximum and minimum void ratios and specific gravity were obtained. Petrographic analyses of the tested sands were also performed to determine their mineralogical composition. A 1-m3 chamber was built for performing the LWD testing in the laboratory. The study was performed for relative densities of 20%, 40%, 60% and 80% to represent the behavior of very loose, loose, medium dense and dense sands. The effect of the existence of a rigid boundary beneath the tested soil on test results was also investigated to determine the zone of influence of the light weight deflectometer.
Relation between proton and neutron asymptotic normalization coefficients for light mirror nuclei and its relevance for nuclear astrophysics

International Nuclear Information System (INIS)

Timofeyuk, N.K.; Johnson, R.C.; Descouvemont, P.

2006-01-01

It has been realised recently that charge symmetry of the nucleon-nucleon interaction leads to a certain relation between Asymptotic Normalization Coefficients (ANCs) in mirror-conjugated one-nucleon overlap integrals. This relation can be approximated by a simple analytical formula that involves mirror neutron and proton separation energies, the core charge and the range of the strong nucleon-core interaction. We perform detailed microscopic multi-channel cluster model calculations and compare their predictions to the simple analytical formula as well as to calculations within a single-particle model in which mirror symmetry in potential wells and spectroscopic factors are assumed. The validity of the latter assumptions is verified on the basis of microscopic cluster model calculations. For mirror pairs in which one of the states is above the proton decay threshold, a link exists between the proton partial width and the ANC of the mirror neutron. This link is given by an approximate analytical formula similar to that for a bound-bound mirror pair. We compare predictions of this formula to the results of microscopic cluster model calculations. Mirror symmetry in ANCs can be used to predict cross sections for proton capture at stellar energies using neutron ANCs measured with stable or ''less radioactive'' beams. (orig.)
Mixed-Degree Spherical Simplex-Radial Cubature Kalman Filter

Directory of Open Access Journals (Sweden)

Shiyuan Wang

2017-01-01

Full Text Available Conventional low degree spherical simplex-radial cubature Kalman filters often generate low filtering accuracy or even diverge for handling highly nonlinear systems. The high-degree Kalman filters can improve filtering accuracy at the cost of increasing computational complexity; nevertheless their stability will be influenced by the negative weights existing in the high-dimensional systems. To efficiently improve filtering accuracy and stability, a novel mixed-degree spherical simplex-radial cubature Kalman filter (MSSRCKF is proposed in this paper. The accuracy analysis shows that the true posterior mean and covariance calculated by the proposed MSSRCKF can agree accurately with the third-order moment and the second-order moment, respectively. Simulation results show that, in comparison with the conventional spherical simplex-radial cubature Kalman filters that are based on the same degrees, the proposed MSSRCKF can perform superior results from the aspects of filtering accuracy and computational complexity.
CALCULATION OF A GLARE STOP FOR TWO-MIRROR EXTRA-FOCAL OBJECTIVE

Directory of Open Access Journals (Sweden)

L. F. Zambrano

2017-01-01

Full Text Available Recently, efforts to improve optical characteristics in canonical mirror systems, including aspherical surfaces and corrective aberration capabilities. At the same time, much attention is paid to the development of new optical schemes of two-mirror objectives. Development measures to protect the image plane from stray light and harmful flows with minimal vignetting and screening is one of the most perspective ways for improving the image quality objectives. The only method to eliminate or even reduce these non-constructive rays is to set glare stops. The aim of the work was an improving method for constructing a glare stop to protect the image plane and the creation of a calculation algorithm of glare stop for protecting the image plane based on two-mirror extra-focal objectives.The study was conducted in two stages. In the course of the first stage, the positions of screening and intermediate image plane were obtained, as well as the central screening coefficient. At the second stage, an arrangement for the position of glare stop is proposed using the algorithm calculation. Thus, mathematical expressions were achieved by geometric constructions. The relation of the screening coefficient with the distance between the surfaces of the mirrors and the height of the paraxial rays is established. А representation of vignetting diagram for two-mirror extra-focal objective with D/f´ = 1 : 1,3 and 2ω = 4° was realized. The Q estimation of vignetting of inclined light beams is k= 0,56.
Photonics principles and practices

CERN Document Server

Al-Azzawi, Abdul

2006-01-01

Light The Nature of Light Light and Shadows Thermal Radiation Light Production Light Intensity Light and Colour Laws of Light Optics Plane Mirrors Spherical Mirrors Lenses Prisms Beamsplitters Light Passing through Optical Components Optical Instruments for Viewing Applications Polarization of Light Optical Materials Waves and Diffraction Waves Interference and Diffraction The Diffraction Grating Interferometers Spectrometers and Spectroscopes Optical Fibres Fibre Optic Cables Advanced Fibre Optic Cables Light Attenuation in Optical Components Fibre-Optic Cable Types and Installations Fibre-Optic Connectors Passive Fibre Optic Devices Wavelength Division Multiplexer Optical Amplifiers Optical Receivers Lasers Optical Switches Optical Fibre Communications Fibre Optic Lighting Testing Fibre Optic Testing Safety Photonics Laboratory Safety Miscellaneous Appendix A: Details of the Devices, Components, Tools, and Parts Appendix B: Alignment Procedure of a Conventional Ar...
Grating exchange system of independent mirror supported by floating rotary stage

Science.gov (United States)

Zhang, Jianhuan; Tao, Jin; Liu, Yan; Nan, Yan

2015-10-01

The performance of The Grating Exchange System can satisfy the Thirty Meter Telescope - TMT for astronomical observation WFOS index requirements and satisfy the requirement of accuracy in the grating exchange. It is used to install in the MOBIE and a key device of MOBIE. The Wide Field Optical Spectrograph (WFOS) is one of the three first-light observing capabilities selected by the TMT Science Advisory Committee. The Multi-Object Broadband Imaging Echellette (MOBIE) instrument design concept has been developed to address the WFOS requirements as described in the TMT Science-Based Requirements Document (SRD). The Grating Exchange System uses a new type of separate movement way of three grating devices and a mirror device. Three grating devices with a mirror are able to achieve independence movement. This kind of grating exchange system can effectively solve the problem that the volume of the grating change system is too large and that the installed space of MOBIE instruments is too limit. This system adopts the good stability, high precision of rotary stage - a kind of using air bearing (Air bearing is famous for its ultra-high precision, and can meet the optical accuracy requirement) and rotation positioning feedback gauge turntable to support grating device. And with a kind of device which can carry greater weight bracket fixed on the MOBIE instrument, with two sets of servo motor control rotary stage and the mirror device respectively. And we use the control program to realize the need of exercising of the grating device and the mirror device. Using the stress strain analysis software--SolidWorks for stress and strain analysis of this structure. And then checking the structure of the rationality and feasibility. And prove that this system can realize the positioning precision under different working conditions can meet the requirements of imaging optical grating diffraction efficiency and error by the calculation and optical performance analysis.
Hearing sounds, understanding actions: action representation in mirror neurons.

Science.gov (United States)

Kohler, Evelyne; Keysers, Christian; Umiltà, M Alessandra; Fogassi, Leonardo; Gallese, Vittorio; Rizzolatti, Giacomo

2002-08-02

Many object-related actions can be recognized by their sound. We found neurons in monkey premotor cortex that discharge when the animal performs a specific action and when it hears the related sound. Most of the neurons also discharge when the monkey observes the same action. These audiovisual mirror neurons code actions independently of whether these actions are performed, heard, or seen. This discovery in the monkey homolog of Broca's area might shed light on the origin of language: audiovisual mirror neurons code abstract contents-the meaning of actions-and have the auditory access typical of human language to these contents.
The manufacturing and metrology of off-axis mirrors

Science.gov (United States)

Penzkofer, Karlheinz; Rascher, Rolf; Küpper, Lutz; Liebl, Johannes

2015-10-01

Especially in the area of the large mirror manufacturing only a few manufacturers are capable to produce optical surfaces of high quality. Therefore a deterministic process should be developed in the project IFasO. In the field of telescope optics off-axis optical systems are becoming increasingly important. These systems try to avoid an obstructing of the incoming light by moving the secondary mirror out of the primary mirror's optical axis. This advantage leads to an increasing market for this type of optical surface. Until now off-axis mirrors were difficult or almost impossible to produce. With the processes developed in IFasO, high quality mirrors become possible. For this reason, this paper describes the manufacturing of off-axis surfaces and its problems. The mirror production used in the project IFasO is based on the specific design of the CNC center developed by the company Optotech. This center UPG2000 is capable of grinding, polishing, sagitta measurement and interferometric measurement in one mounting of the specimen. Usually a large optics has to be transported during their manufacturing after every individual process step. There is always a risk of damage of the specimen. The exact orientation of the surface relatively to the tool position is also required. This takes a huge amount of time and makes up most of the production time. In this presentation the use of UPG2000 and the next steps within the process development are described. In the current status the manufacturing of large off-axis elements with a PV < λ/10 rms is reproducible.
Light weight hollow maxillary complete denture: A case series

Directory of Open Access Journals (Sweden)

Laxman Singh Kaira

2012-01-01

Full Text Available Retention, stability and support are the basic principles on which the success of a complete denture relies on. The skill lies in applying these principles efficiently in critical situations. Residual ridge resorption occurs at a three times faster rate in mandibular arch than in the maxillary arch. The severely resorbed maxillary and mandibular edentulous arches that are narrow and constricted with increased interarch space provide decreased support, retention and stability. The consequent weight of the processed complete denture only compromises them further. The severely resorbed jaw can have various treatment options. Extreme resorption of the maxillary denture-bearing area may lead to problems with prosthetic rehabilitation. The advantage of a hollow maxillary or mandibular denture is the reduction of excessive weight of acrylic resin, which normally replaces lost alveolar ridge in the interridge space of the denture wearer. This clinical report describes two case reports of edentulous patients with resorbed ridges where a simplified technique of fabricating a light weight hollow maxillary complete denture was used for the preservation of denture bearing areas.
Beyond Extreme Ultra Violet (BEUV) Radiation from Spherically symmetrical High-Z plasmas

Science.gov (United States)

Yoshida, Kensuke; Fujioka, Shinsuke; Higashiguchi, Takeshi; Ugomori, Teruyuki; Tanaka, Nozomi; Kawasaki, Masato; Suzuki, Yuhei; Suzuki, Chihiro; Tomita, Kentaro; Hirose, Ryouichi; Eshima, Takeo; Ohashi, Hayato; Nishikino, Masaharu; Scally, Enda; Nshimura, Hiroaki; Azechi, Hiroshi; O'Sullivan, Gerard

2016-03-01

Photo-lithography is a key technology for volume manufacture of high performance and compact semiconductor devices. Smaller and more complex structures can be fabricated by using shorter wavelength light in the photolithography. One of the most critical issues in development of the next generation photo-lithography is to increase energy conversion efficiency (CE) from laser to shorter wavelength light. Experimental database of beyond extreme ultraviolet (BEUV) radiation was obtained by using spherically symmetrical high-Z plasmas generated with spherically allocated laser beams. Absolute energy and spectra of BEUV light emitted from Tb, Gd, and Mo plasmas were measured with a absolutely calibrated BEUV calorimeter and a transmission grating spectrometer. 1.0 x 1012 W/cm2 is the optimal laser intensity to produced efficient BEUV light source plasmas with Tb and Gd targets. Maximum CE is achieved at 0.8% that is two times higher than the published CEs obtained with planar targets.
Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy.

Science.gov (United States)

Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

2016-05-01

X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or "tophat" beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.
Active optics and the axisymmetric case: MINITRUST wide-field three-reflection telescopes with mirrors aspherized from tulip and vase forms

Science.gov (United States)

Lemaitre, Gerard R.; Montiel, Pierre; Joulie, Patrice; Dohlen, Kjetil; Lanzoni, Patrick

2004-09-01

Wide-field astronomy requires larger size telescopes. Compared to the catadioptric Schmidt, the optical properties of a three mirror telescope provides significant advantages. (1) The flat field design is anastigmatic at any wavelength, (2) the system is extremely compact -- four times shorter than a Schmidt -- and, (3) compared to a Schmidt with refractive corrector -- requiring the polishing of three optical surfaces --, the presently proposed Modified-Rumsey design uses all of eight available free parameters of a flat fielded anastigmatic three mirror telescope for mirrors generated by active optics methods. Compared to a Rumsey design, these parameters include the additional slope continuity condition at the primary-tertiary link for in-situ stressing and aspherization from a common sphere. Then, active optics allows the polishing of only two spherical surfaces: the combined primary-tertiary mirror and the secondary mirror. All mirrors are spheroids of the hyperboloid type. This compact system is of interest for space and ground-based astronomy and allows to built larger wide-field telescopes such as demonstrated by the design and construction of identical telescopes MINITRUST-1 and -2, f/5 - 2° FOV, consisting of an in-situ stressed double vase form primary-tertiary and of a stress polished tulip form secondary. Optical tests of these telescopes, showing diffraction limited images, are presented.
Saltation movement of large spherical particles

Science.gov (United States)

Chara, Z.; Dolansky, J.; Kysela, B.

2017-07-01

The paper presents experimental and numerical investigations of the saltation motion of a large spherical particle in an open channel. The channel bottom was roughed by one layer of glass rods of diameter 6 mm. The plastic spheres of diameter 25.7 mm and density 1160 kgm-3 were fed into the water channel and theirs positions were viewed by a digital camera. Two light sheets were placed above and under the channel, so the flow was simultaneously lighted from the top and the bottom. Only particles centers of which moved through the light sheets were recorded. Using a 2D PIV method the trajectories of the spheres and the velocity maps of the channel flow were analyzed. The Lattice-Boldzmann Method (LBM) was used to simulate the particle motion.
Diagnostic mirror concept development for use in the complex environment of a fusion reactor

Energy Technology Data Exchange (ETDEWEB)

Krimmer, Andreas Joachim

2016-07-01

Light-based diagnostic systems of fusion reactors require optical mirrors to channel light through the structures surrounding the plasma. With increasing plasma volume, power and plasma burn time, the environmental conditions grow more demanding and new requirements arise. In this dissertation, the design of optical mirrors inside the vacuum chamber of the prototype reactor ITER (Latin ''the way'') and future fusion power plants are investigated. Comparing the state of the art with the boundary conditions close to the fusion plasma, existing mirror designs and choices for the reflective surface are evaluated. For the design, it is not the individual boundary conditions that are critical, but rather, their combination and the resulting interactions. Drawing from the existing designs, possible realizations for central functionality are discussed. Included in the discussion are substrate choice, mounting, adjustment and thermal contacting as well as positioning of the mirror assembly compatible with hot cell maintenance. Building on the general discussion, mirror concepts for the charge exchange recombination spectroscopy (CXRS) diagnostic system for the ITER plasma core are proposed and simulated. In addition, prototypes are manufactured and tested to assess critical aspects of the proposed design. Testing includes positioning by pins, manufacturing of a stainless steel substrate with fluid channels adapted to the mirror shape, and tests with an SiO{sub 2} /TiO{sub 2} dielectric coating under selected ITER conditions. As a result of the work, the fusion reactor mirror design considerations given in the principal design discussion can be used as a basis for other diagnostic systems as well. In the case of the core CXRS mirror concept for ITER, the basic suitability was shown and critical topics were identified where additional work is necessary.
Diagnostic mirror concept development for use in the complex environment of a fusion reactor

International Nuclear Information System (INIS)

Krimmer, Andreas Joachim

2016-01-01

Light-based diagnostic systems of fusion reactors require optical mirrors to channel light through the structures surrounding the plasma. With increasing plasma volume, power and plasma burn time, the environmental conditions grow more demanding and new requirements arise. In this dissertation, the design of optical mirrors inside the vacuum chamber of the prototype reactor ITER (Latin ''the way'') and future fusion power plants are investigated. Comparing the state of the art with the boundary conditions close to the fusion plasma, existing mirror designs and choices for the reflective surface are evaluated. For the design, it is not the individual boundary conditions that are critical, but rather, their combination and the resulting interactions. Drawing from the existing designs, possible realizations for central functionality are discussed. Included in the discussion are substrate choice, mounting, adjustment and thermal contacting as well as positioning of the mirror assembly compatible with hot cell maintenance. Building on the general discussion, mirror concepts for the charge exchange recombination spectroscopy (CXRS) diagnostic system for the ITER plasma core are proposed and simulated. In addition, prototypes are manufactured and tested to assess critical aspects of the proposed design. Testing includes positioning by pins, manufacturing of a stainless steel substrate with fluid channels adapted to the mirror shape, and tests with an SiO_2 /TiO_2 dielectric coating under selected ITER conditions. As a result of the work, the fusion reactor mirror design considerations given in the principal design discussion can be used as a basis for other diagnostic systems as well. In the case of the core CXRS mirror concept for ITER, the basic suitability was shown and critical topics were identified where additional work is necessary.
Strength characteristics of light weight concrete blocks using mineral admixtures

Science.gov (United States)

Bhuvaneshwari, P.; Priyadharshini, U.; Gurucharan, S.; Mithunram, B.

2017-07-01

This paper presents an experimental study to investigate the characteristics of light weight concrete blocks. Cement was partially replaced with mineral admixtures like Fly ash (FA), limestone powder waste (LPW), Rice husk ash (RHA), sugarcane fiber waste (SCW) and Chrysopogonzizanioides (CZ). The maximum replacement level achieved was 25% by weight of cement and sand. Total of 56 cubes (150 mm x 150 mm x150 mm) and 18 cylinders (100mmφ and 50mm depth) were cast. The specimens being (FA, RHA, SCW, LPW, CZ, (FA-RHA), (FA-LPW), (FA-CZ), (LPW-CZ), (FA-SCW), (RHA-SCW)).Among the different combination, FA,FA-SCW,CZ,FA-CZ showed enhanced strength and durability, apart from achieving less density.
Amorphous Metals and Composites as Mirrors and Mirror Assemblies

Science.gov (United States)

Hofmann, Douglas C. (Inventor); Davis, Gregory L. (Inventor); Agnes, Gregory S. (Inventor); Shapiro, Andrew A. (Inventor)

2016-01-01

A mirror or mirror assembly fabricated by molding, pressing, assembling, or depositing one or more bulk metal glass (BMG), bulk metal glass composite (BMGMC), or amorphous metal (AM) parts and where the optical surface and backing of the mirror can be fabricated without machining or polishing by utilizing the unique molding capabilities of this class of materials.
Mirror machine reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Moir, R.W.

1976-01-01

Recent mirror reactor conceptual design studies are described. Considered in detail is the design of ''standard'' Yin-Yang fusion power reactors with classical and enhanced confinement. It is shown that to be economically competitive with estimates for other future energy sources, mirror reactors require a considerable increase in Q, or major design simplifications, or preferably both. These improvements may require a departure from the ''standard'' configuration. Two attractive possibilities, both of which would use much of the same physics and technology as the ''standard'' mirror, are the field reversed mirror and the end-stoppered mirror
Design and fabrication of light weight current collectors for direct methanol fuel cells using the micro-electro mechanical system technique

Science.gov (United States)

Sung, Min-Feng; Kuan, Yean-Der; Chen, Bing-Xian; Lee, Shi-Min

The direct methanol fuel cell (DMFC) is suitable for portable applications. Therefore, a light weight and small size is desirable. The main objective of this paper is to design and fabricate a light weight current collector for DMFC usage. The light weight current collector mainly consists of a substrate with two thin film metal layers. The substrate of the current collector is an FR4 epoxy plate. The thin film metal layers are accomplished by the thermo coater technique to coat metal powders onto the substrate surfaces. The developed light weight current collectors are further assembled to a single cell DMFC test fixture to measure the cell performance. The results show that the proposed current collectors could even be applied to DMFCs because they are light, thin and low cost and have potential for mass production.
Walk like me, talk like me. The connection between mirror neurons and autism spectrum disorder.

Science.gov (United States)

Saffin, Jillian M; Tohid, Hassaan

2016-04-01

Understanding social cognition has become a hallmark in deciphering autism spectrum disorder. Neurobiological theories are taking precedence in causation studies as researchers look to abnormalities in brain development as the cause of deficits in social behavior, cognitive processes, and language. Following their discovery in the 1990s, mirror neurons have become a dominant theory for that the mirror neuron system may play a critical role in the pathophysiology of various symptoms of autism. Over the decades, the theory has evolved from the suggestion of a broken mirror neuron system to impairments in mirror neuron circuitry. The mirror neuron system has not gained total support due to inconsistent findings; a comprehensive analysis of the growing body of research could shed light on the benefits, or the disadvantage of continuing to study mirror neurons and their connection to autism.

Relativistic electron mirrors from high intensity laser nanofoil interactions

International Nuclear Information System (INIS)

Kiefer, Daniel

2012-01-01

The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ 2 , where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those
Classical mirror symmetry

CERN Document Server

Jinzenji, Masao

2018-01-01

This book furnishes a brief introduction to classical mirror symmetry, a term that denotes the process of computing Gromov–Witten invariants of a Calabi–Yau threefold by using the Picard–Fuchs differential equation of period integrals of its mirror Calabi–Yau threefold. The book concentrates on the best-known example, the quintic hypersurface in 4-dimensional projective space, and its mirror manifold. First, there is a brief review of the process of discovery of mirror symmetry and the striking result proposed in the celebrated paper by Candelas and his collaborators. Next, some elementary results of complex manifolds and Chern classes needed for study of mirror symmetry are explained. Then the topological sigma models, the A-model and the B-model, are introduced. The classical mirror symmetry hypothesis is explained as the equivalence between the correlation function of the A-model of a quintic hyper-surface and that of the B-model of its mirror manifold. On the B-model side, the process of construct...
Evaluation of the light weight Juggling system

Directory of Open Access Journals (Sweden)

Erev-Yehene Vered

2011-12-01

Full Text Available This paper presents the training of juggling skills, a highly complex problem of coordination, under tight time and space constraints. This training is achieved with a simple training platform, a light weight juggling platform (LWJ, and is compared to training with real balls. The principle directing the design of the platform is to obtain a simple tool. The simplification, in comparison to real world juggling, is based on the identification of invariant properties in the spatiotemporal coordination of intermediate and expert jugglers. Two classes training solutions were added to the LWJ: An audio-tactile pacing or augmented multimodal environment, and the manipulation of cognitive components of the juggling skills. The transfer to juggling with real balls was evaluated in four different experiments.
Noise and light exposures for extremely low birth weight newborns during their stay in the neonatal intensive care unit.

Science.gov (United States)

Lasky, Robert E; Williams, Amber L

2009-02-01

The objectives of this study were to characterize noise and light levels for extremely low birth weight newborns throughout their stay in the NICU, evaluate factors influencing noise and light levels, and determine whether exposures meet recommendations from the American Academy of Pediatrics. Sound and light were measured inside the beds of extremely low birth weight newborns (n = 22) from birth to discharge. Measurements were recorded for 20 consecutive hours weekly from birth until 36 weeks' postmenstrual age, biweekly until 40 weeks, and every 4 weeks thereafter. Clinical variables including bed type and method of respiratory support were recorded at each session. Age-related changes in respiratory support and bed type explained the weekly increase of 0.22 dB in sound level and 3.67 lux in light level. Old incubators were the noisiest bed types, and new incubators were the quietest. Light levels were significantly higher in open beds than in incubators. The variations in noise and light levels over time were greatest for open beds. Noise and light levels were much less affected by respiratory support in incubators compared with open beds. A typical extremely low birth weight neonate was exposed to noise levels averaging 56.44 dB(A) and light levels averaging 70.56 lux during their stay from 26 to 42 weeks' postmenstrual age in the NICU. Noise levels were rarely within American Academy of Pediatrics recommendations (5.51% of the time), whereas light levels almost always met recommendations (99.37% of the time). Bed type and respiratory support explained differences in noise and light levels that extremely low birth weight newborns experience during their hospital stay. Noise levels exceeded recommendations, although evidence supporting those recommendations is lacking. Well-designed intervention studies are needed to determine the effects of noise reduction on the development of extremely low birth weight newborns.
Controlling resonance energy transfer in nanostructure emitters by positioning near a mirror

Science.gov (United States)

Weeraddana, Dilusha; Premaratne, Malin; Gunapala, Sarath D.; Andrews, David L.

2017-08-01

The ability to control light-matter interactions in quantum objects opens up many avenues for new applications. We look at this issue within a fully quantized framework using a fundamental theory to describe mirror-assisted resonance energy transfer (RET) in nanostructures. The process of RET communicates electronic excitation between suitably disposed donor and acceptor particles in close proximity, activated by the initial excitation of the donor. Here, we demonstrate that the energy transfer rate can be significantly controlled by careful positioning of the RET emitters near a mirror. The results deliver equations that elicit new insights into the associated modification of virtual photon behavior, based on the quantum nature of light. In particular, our results indicate that energy transfer efficiency in nanostructures can be explicitly expedited or suppressed by a suitably positioned neighboring mirror, depending on the relative spacing and the dimensionality of the nanostructure. Interestingly, the resonance energy transfer between emitters is observed to "switch off" abruptly under suitable conditions of the RET system. This allows one to quantitatively control RET systems in a new way.
High order harmonic generation from plasma mirrors

International Nuclear Information System (INIS)

George, H.

2010-01-01

When an intense laser beam is focused on a solid target, the target's surface is rapidly ionized and forms dense plasma that reflects the incident field. For laser intensities above few 10 to the power of 15 Wcm -2 , high order harmonics of the laser frequency, associated in the time domain to a train of atto-second pulses (1 as 10 -18 s), can be generated upon this reflection. In this thesis, we developed numerical tools to reveal original aspects of harmonic generation mechanisms in three different interaction regime: the coherent wake emission, the relativistic emission and the resonant absorption. In particular, we established the role of these mechanisms when the target is a very thin foil (thickness of the order of 100 nm). Then we study experimentally the spectral, spatial and coherence properties of the emitted light. We illustrate how to exploit these measurements to get information on the plasma mirror dynamics on the femtosecond and atto-second time scales. Last, we propose a technique for the single-shot complete characterization of the temporal structure of the harmonic light emission from the laser-plasma mirror interaction. (author)
Tandem mirror and field-reversed mirror experiments

Energy Technology Data Exchange (ETDEWEB)

Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

1979-08-21

This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.
Mirror symmetry

CERN Document Server

Voisin, Claire

1999-01-01

This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...
Technology of mirror machines: LLL facilities for magnetic mirror fusion experiments

International Nuclear Information System (INIS)

Batzer, T.H.

1977-01-01

Significant progress in plasma confinement and temperature has been achieved in the 2XIIB facility at Livermore. These encouraging results, and their theoretical corroboration, have provided a firm basis for the design of a new generation of magnetic mirror experiments, adding support to the mirror concept of a fusion reactor. Two new mirror experiments have been proposed to succeed the currently operating 2XIIB facility. The first of these called TMX (Tandem Mirror Experiment) has been approved and is currently under construction. TMX is designed to utilize the intrinsic positive plasma potential of two strong, and relatively small, minimum B mirror cells to enhance the confinement of a much larger, magnetically weaker, centrally-located mirror cell. The second facility, MFTF (Mirror Fusion Test Facility), is currently in preliminary design with line item approval anticipated for FY 78. MFTF is designed primarily to exploit the experimental and theoretical results derived from 2XIIB. Beyond that, MFTF will develop the technology for the transition from the present small mirror experiments to large steady-state devices such as the mirror FERF/FTR. The sheer magnitude of the plasma volume, magnetic field, neutral beam power, and vacuum pumping capacity, particularly in the case of MFTF, has placed new and exciting demands on engineering technology. An engineering overview of MFTF, TMX, and associated MFE activities at Livermore will be presented
On Empathy: The Mirror Neuron System and Art Education

Science.gov (United States)

Jeffers, Carol S.

2009-01-01

This paper re/considers empathy and its implications for learning in the art classroom, particularly in light of relevant neuroscientific investigations of the mirror neuron system recently discovered in the human brain. These investigations reinterpret the meaning of perception, resonance, and connection, and point to the fundamental importance…
Filling material for a buried cavity in a collapse area using light-weighted foam and active feldspar

Science.gov (United States)

Cho, Jin Woo; Lee, Ju-hyoung; Kim, Sung-Wook; Choi, Eun-Kyeong

2017-04-01

Concrete which is generally used as filling material for a buried cavity has very high strength but significantly high self-load is considered its disadvantage. If it is used as filling material, the second collapse due to additional load, causing irreversible damage. If light-weighted foam and active feldspar are used to solve this problem, the second collapse can be prevented by reducing of self-load of filling material. In this study, the specimen was produced by mixing light-weighted foam, active feldspar and cement, and changes in the density, unconfined compressive strength and hydraulic conductivity were analyzed. Using the light-weighted foam could enable the adjustment of density of specimen between 0.5 g/cm3 and 1.7 g/cm3, and if the mixing ratio of the light-weighted foam increases, the specimen has more pores and smaller range of cross-sectional area. It is confirmed that it has direct correlation with the density, and if the specimen has more pores, the density of the specimen is lowered. The density of the specimen influences the unconfined compressive strength and the hydraulic conductivity, and it was also confirmed that the unconfined compressive strength could be adjusted between 0.6 MPa and 8 MPa and the hydraulic conductivity could be adjusted between 10-9cm/sec and 10-3cm/sec. These results indicated that we can adjust unconfined compressive strength and hydraulic conductivity of filling materials by changing the mixing amount of lightweight-weighted foam according to the requirements of the field condition. Keywords: filling material, buried cavity, light-weighted foam, feldspar Acknowledgement This research was supported by a Grant from a Strategic Research Project (Horizontal Drilling and Stabilization Technologies for Urban Search and Rescue (US&R) Operation) funded by the Korea Institute of Civil Engineering and Building Technology.
[Motion control of moving mirror based on fixed-mirror adjustment in FTIR spectrometer].

Science.gov (United States)

Li, Zhong-bing; Xu, Xian-ze; Le, Yi; Xu, Feng-qiu; Li, Jun-wei

2012-08-01

The performance of the uniform motion of the moving mirror, which is the only constant motion part in FTIR spectrometer, and the performance of the alignment of the fixed mirror play a key role in FTIR spectrometer, and affect the interference effect and the quality of the spectrogram and may restrict the precision and resolution of the instrument directly. The present article focuses on the research on the uniform motion of the moving mirror and the alignment of the fixed mirror. In order to improve the FTIR spectrometer, the maglev support system was designed for the moving mirror and the phase detection technology was adopted to adjust the tilt angle between the moving mirror and the fixed mirror. This paper also introduces an improved fuzzy PID control algorithm to get the accurate speed of the moving mirror and realize the control strategy from both hardware design and algorithm. The results show that the development of the moving mirror motion control system gets sufficient accuracy and real-time, which can ensure the uniform motion of the moving mirror and the alignment of the fixed mirror.
The mirror neuron system and the strange case of Broca's area.

Science.gov (United States)

Cerri, Gabriella; Cabinio, Monia; Blasi, Valeria; Borroni, Paola; Iadanza, Antonella; Fava, Enrica; Fornia, Luca; Ferpozzi, Valentina; Riva, Marco; Casarotti, Alessandra; Martinelli Boneschi, Filippo; Falini, Andrea; Bello, Lorenzo

2015-03-01

Mirror neurons, originally described in the monkey premotor area F5, are embedded in a frontoparietal network for action execution and observation. A similar Mirror Neuron System (MNS) exists in humans, including precentral gyrus, inferior parietal lobule, and superior temporal sulcus. Controversial is the inclusion of Broca's area, as homologous to F5, a relevant issue in light of the mirror hypothesis of language evolution, which postulates a key role of Broca's area in action/speech perception/production. We assess "mirror" properties of this area by combining neuroimaging and intraoperative neurophysiological techniques. Our results show that Broca's area is minimally involved in action observation and has no motor output on hand or phonoarticulatory muscles, challenging its inclusion in the MNS. The presence of these functions in premotor BA6 makes this area the likely homologue of F5 suggesting that the MNS may be involved in the representation of articulatory rather than semantic components of speech. © 2014 Wiley Periodicals, Inc.
USE OF MIRROR PATTERN CUTTING OF NETTING MATERIALS FOR CONSTRUCTION OF LAKE BEACH SEINES

Directory of Open Access Journals (Sweden)

A. Nazarov

2014-12-01

Full Text Available Purpose. Justification and calculation of a new methodological approach to the construction of a standard beach seine (502 / 302 х 3.75 with the use of the properties of mirror netting ensuring the saving of the netting material, reduction of weight, price and drag resistance. Methodology. The carp age group selectivity of the constructed seine was assessed within fish fauna monitoring based on the catch analysis of monitoring gill nets with mesh sizes of 30-130 mm according to generally accepted methods [9, 10]. Calculation of netting materials and ropes was carried out according to generally accepted methods [12-14]. Seine resistance was calculated according to N. T. Senin formula for different netting materials and the angles of the movement of different seine parts in water [2]. The gear reliability and data processing were carried out according to standard methods [11, 14, 15]. Findings. A variant of the construction of the maximum lightweight beach lake seines made of mirror pattern netting taking into account the properties of the mirror pattern netting material, reduction of weight, price and drag resistance has been proposed. The provided recalculation of the properties of a serial seine made of rhombic mesh for the mirror netting seine taking into account netting properties allowed: 1 reducing the seine drag resistance value by 1,4 times; 2 reducing the weight of netting materials by 16.3% compared to the prototype; 3 increasing the seine selectivity when fishing older age groups of carp in non-drainable ponds. Originality. We presented the method of the calculation and construction of lake beach seines made of mirror netting, analyzed the technological stages of the construction of mirror netting, determined main qualitative and technological parameters, which had effect on the conditions of the construction and reliability of such fishing gears. A new method of the use of an insert of the combined netting material cutting ensuring
Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors

OpenAIRE

Lin, Yali; Yang, Yujie; Shan, Yuwei; Gong, Lingli; Chen, Jingzhi; Li, Sensen; Chen, Lujian

2017-01-01

Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidi...
Design of a {O}94 cm mirror mount for the Petawatt Project on Nova

Energy Technology Data Exchange (ETDEWEB)

Hamilton, R.; Tietbohl, G.L.

1995-10-01

The authors have designed a large optical gimbal mount that will be used on the Petawatt Project currently under construction on the Nova laser. These mounts are designed to hold and tilt {O}94 cm mirrors and gratings that will redirect the {O}60 cm beam through the Petawatt vacuum compressor. Lacking the commercial availability to house this size optic, they have engineered a large mirror mount with a high natural frequency (42 Hz), low self-weight deflection of the mirror (< {lambda}/46), and high positioning accuracy characteristics (< 1 {micro}rad using flexures and stepping motors). Analysis details and methodology are presented.
Design of a OE 94 cm mirror mount for the Petawatt Project on Nova

International Nuclear Information System (INIS)

Hamilton, R.; Tietbohl, G.L.

1995-10-01

The authors have designed a large optical gimbal mount that will be used on the Petawatt Project currently under construction on the Nova laser. These mounts are designed to hold and tilt OE 94 cm mirrors and gratings that will redirect the OE 60 cm beam through the Petawatt vacuum compressor. Lacking the commercial availability to house this size optic, they have engineered a large mirror mount with a high natural frequency (42 Hz), low self-weight deflection of the mirror (< λ/46), and high positioning accuracy characteristics (< 1 microrad using flexures and stepping motors). Analysis details and methodology are presented
Effect of molecular weight on the quality of poly(alpha-methylstyrene mandrel

Directory of Open Access Journals (Sweden)

Xiuyun Shangguan

2017-07-01

Full Text Available Hollow poly(alpha-methylstyrene (PAMS shows application in inertial confinement fusion experiments as the degradable mandrels of glow plasma polymer shells. However, the molecular weight of PAMS has great influence on the quality of mandrels. In this work, this influence was systematically studied using several PAMS samples with different molecular weights. For PAMS shells with 900 μm inner diameter and different wall thickness, when the molecular weight of PAMS is in the range of 300–500 kg·mol−1, perfect sphericity and good wall thickness uniformity can be obtained. In contrast, when increasing molecular weight to 800 kg·mol−1, the sphericity and the wall thickness uniformity become worse. Moreover, compared with the wall uniformity, the sphericity of PAMS shells was much less sensitive to the molecular weight. The results also showed that the stability of W1/O compound droplets of PAMS shells were less affected by the molecular weight. It was revealed that the wall uniformity and the sphericity of the PAMS shells were associated with the diffusion rates of fluorobenzene (FB.
Tandem mirror magnet system for the mirror fusion test facility

International Nuclear Information System (INIS)

Bulmer, R.H.; Van Sant, J.H.

1980-01-01

The Tandem Mirror Fusion Test Facility (MFTF-B) will be a large magnetic fusion experimental facility containing 22 supercounducting magnets including solenoids and C-coils. State-of-the-art technology will be used extensively to complete this facility before 1985. Niobium titanium superconductor and stainless steel structural cases will be the principle materials of construction. Cooling will be pool boiling and thermosiphon flow of 4.5 K liquid helium. Combined weight of the magnets will be over 1500 tonnes and the stored energy will be over 1600 MJ. Magnetic field strength in some coils will be more than 8 T. Detail design of the magnet system will begin early 1981. Basic requirements and conceptual design are disclosed in this paper
Data Base for Light-Weight Automotive Diesel Power Plants: Volume 1. Executive Summary.

Science.gov (United States)

1979-12-01

The effects on fuel economy, emissions, passenger car safety and other variables due to the installation of light-weight Diesel powerplants were studied. Experimental data was obtained on naturally aspirated and turbocharged Diesel engines installed ...

Data Base for Light-Weight Automotive Diesel Power Plants : Volume 3. Miscellaneous Data.

Science.gov (United States)

1979-12-01

The effects of fuel economy, emissions, passenger car safety and other variables due to the installation of light-weight Diesel powerplants were studied. Experimental data was obtained on naturally aspirated and turbocharged Diesel engines installed ...
Impact of large field angles on the requirements for deformable mirror in imaging satellites

Science.gov (United States)

Kim, Jae Jun; Mueller, Mark; Martinez, Ty; Agrawal, Brij

2018-04-01

For certain imaging satellite missions, a large aperture with wide field-of-view is needed. In order to achieve diffraction limited performance, the mirror surface Root Mean Square (RMS) error has to be less than 0.05 waves. In the case of visible light, it has to be less than 30 nm. This requirement is difficult to meet as the large aperture will need to be segmented in order to fit inside a launch vehicle shroud. To reduce this requirement and to compensate for the residual wavefront error, Micro-Electro-Mechanical System (MEMS) deformable mirrors can be considered in the aft optics of the optical system. MEMS deformable mirrors are affordable and consume low power, but are small in size. Due to the major reduction in pupil size for the deformable mirror, the effective field angle is magnified by the diameter ratio of the primary and deformable mirror. For wide field of view imaging, the required deformable mirror correction is field angle dependant, impacting the required parameters of a deformable mirror such as size, number of actuators, and actuator stroke. In this paper, a representative telescope and deformable mirror system model is developed and the deformable mirror correction is simulated to study the impact of the large field angles in correcting a wavefront error using a deformable mirror in the aft optics.
Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy

International Nuclear Information System (INIS)

Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

2016-01-01

X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or “tophat” beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.
Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy

Energy Technology Data Exchange (ETDEWEB)

Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal, E-mail: kawal.sawhney@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

2016-05-15

X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or “tophat” beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.
Investigation of aperiodic W/C multi-layer mirror for X-ray optics

International Nuclear Information System (INIS)

Wang Zhanshan; Cheng Xinbin; Zhu Jingtao; Huang Qiushi; Zhang Zhong; Chen Lingyan

2011-01-01

Design, fabrication and characterization of aperiodic tungsten/carbon (W/C) multi-layer mirror were studied. W/C multi-layer was designed as a broad-angle reflective supermirror for Cu-Kα line (λ = 0.154 nm) in the grazing incident angular range (0.9-1.1 deg.) using simulated annealing algorithm. To deposit the W/C depth-graded multi-layer mirror accurately, we introduce an effective layer growth rate as a function of layer thickness. This method greatly improves the reflectivity curve compared to the conventional multi-layer mirror prepared with constant growth rate. The deposited multi-layer mirror exhibits an average reflectivity of 19% over the grazing incident angle range of 0.88-1.08 deg. which mainly coincides with the designed value. Furthermore, the physical mechanisms were discussed and the re-sputtering process of light-atom layers is accounted for the modification of layer thicknesses which leads to the effective growth rates. Using this calibration method, the aperiodic multi-layer mirrors can be better fabricated for X-ray optics.
Exposure of metal mirrors in the scrape-off layer of TEXTOR

International Nuclear Information System (INIS)

Wienhold, P.; Litnovsky, A.; Philipps, V.; Schweer, B.; Sergienko, G.; Oelhafen, P.; Ley, M.; De Temmerman, G.; Schneider, W.; Hildebrandt, D.; Laux, M.; Rubel, M.; Emmoth, B.

2005-01-01

Large molybdenum mirrors have been exposed in the SOL of TEXTOR in order to simulate conditions relevant for ITER optical components. Distortions of the reflectivity - increase as well as decrease - are found in the erosion and deposition dominated areas, respectively. The changes are most pronounced in the near UV and level off in the IR and can partly be attributed to observed surface changes. A novel periscope system was installed and mirrors exposed in a pilot experiment to simulate the transmission of light to distant sensors in ITER
Light-weight aluminium bridges and bridge decks. An overview of recent applications

NARCIS (Netherlands)

Maljaars, J.; Soetens, F.; Kluyver, D. de

2008-01-01

The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these
Light transport in turbid media with non-scattering, low-scattering and high absorption heterogeneities based on hybrid simplified spherical harmonics with radiosity model.

Science.gov (United States)

Yang, Defu; Chen, Xueli; Peng, Zhen; Wang, Xiaorui; Ripoll, Jorge; Wang, Jing; Liang, Jimin

2013-01-01

Modeling light propagation in the whole body is essential and necessary for optical imaging. However, non-scattering, low-scattering and high absorption regions commonly exist in biological tissues, which lead to inaccuracy of the existing light transport models. In this paper, a novel hybrid light transport model that couples the simplified spherical harmonics approximation (SPN) with the radiosity theory (HSRM) was presented, to accurately describe light transport in turbid media with non-scattering, low-scattering and high absorption heterogeneities. In the model, the radiosity theory was used to characterize the light transport in non-scattering regions and the SPN was employed to handle the scattering problems, including subsets of low-scattering and high absorption. A Neumann source constructed by the light transport in the non-scattering region and formed at the interface between the non-scattering and scattering regions was superposed into the original light source, to couple the SPN with the radiosity theory. The accuracy and effectiveness of the HSRM was first verified with both regular and digital mouse model based simulations and a physical phantom based experiment. The feasibility and applicability of the HSRM was then investigated by a broad range of optical properties. Lastly, the influence of depth of the light source on the model was also discussed. Primary results showed that the proposed model provided high performance for light transport in turbid media with non-scattering, low-scattering and high absorption heterogeneities.
FACT. Normalized and asynchronous mirror alignment for Cherenkov telescopes

Energy Technology Data Exchange (ETDEWEB)

Mueller, Sebastian Achim [ETH Zurich (Switzerland); Buss, Jens [TU Dortmund (Germany)

2016-07-01

Imaging Atmospheric Cherenkov Telescopes (IACTs) need fast and large imaging optics to map the faint Cherenkov light emitted in cosmic ray air showers onto their image sensors. Segmented reflectors are inexpensive, lightweight and offer good image quality. However, alignment of the mirror facets remains a challenge. A good alignment is crucial in IACT observations to separate gamma rays from hadronic cosmic rays. We present a star tracking alignment method which is not restricted to clear nights. It normalizes the mirror facet reflections to be independent of the reference star or the cloud coverage. It records asynchronously of the telescope drive which makes the method easy to integrate in existing telescopes. It can be combined with remote facet actuation, but it does not need one to work. Furthermore, it can reconstruct all individual mirror facet point spread functions. We present the method and alignment results on the First Geiger-mode Photo Diode Avalanche Cherenkov Telescope (FACT) on the Canary Island of La Palma, Spain.
Relativistic electron mirrors from high intensity laser nanofoil interactions

Energy Technology Data Exchange (ETDEWEB)

Kiefer, Daniel

2012-12-21

The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those
The ''Dolphin'' power laser installation for spherical thermonuclear target heating

International Nuclear Information System (INIS)

Basov, N.G.; Bykovskij, N.E.; Danilov, A.E.

1978-01-01

12-channel laser installation the ''Dolphin'' for thermonuclear target heating in the radiation spheric geometry has been developed to carry out series of physical investigations of laser-thermonuclear plasma system, optimization of target heating conditions and obtaining a comparatively large value of thermonuclear output in ratio to the energy of absorbed light radiation in the target. The description of installation main elements, consisting of the following components, is given: 1)neodymium laser with the maximum permissible radiation energy of 10kJ, with light pulse duration of 10 -10 /10 -9 c and radiation divergence of approximately 5x10 -4 rad; 2)vacuum chamber, where laser radiation interaction with plasma takes place; 3)diagnostic means of laser and plasma parameters and 4)focus system. The focus system provides a high degree of target spherical radiation symmetry at current maximum density on its surface of approximately 10 15 W/cm 2
Low Cost, Light Weight Materials for Mirrors, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — During the phase I program Northwestern and APS, Inc., have manufactured several different materials systems that are lighter than Beryllium and stiffer than...
Mirror and (absence of) counter-mirror responses to action sounds measured with TMS.

Science.gov (United States)

Ticini, Luca F; Schütz-Bosbach, Simone; Waszak, Florian

2017-11-01

To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed 'mirror' and 'counter-mirror' trainings (a 'mirror' training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition. © The Author (2017). Published by Oxford University Press.
Measurements of diamond-turned copper mirrors at glancing incidence

International Nuclear Information System (INIS)

Kimura, W.D.; Saito, T.T.

1987-01-01

The results of glancing incidence absorptance measurements performed on diamond-turned copper mirrors are presented. A photoacoustic calorimetry technique is used in which the output from a low power, chopped cw Nd:YAG laser (1.06 μm) is incident upon the mirror at angles of incidence from 0 to 87 0 , for both s and p-polarizations. Measurements are obtained as a function of the diamond turning groove orientation with respect to the plane of incidence. Minimum absorptance, at high angles of incidence, is achieved with s-polarized light and with the grooves aligned parallel to the plane of incidence. The affects on the absorptance of a large scratch at glancing incidence are also described
Measurements of diamond turned copper mirrors at glancing incidence

International Nuclear Information System (INIS)

Kimura, W.D.; Saito, T.T.

1987-01-01

The results of glancing incidence absorptance measurements performed on diamond turned copper mirrors are presented. A photoacoustic calorimetry technique is used in which the output from a low power, chopped cw Nd:YAG laser (1.06 μm) is incident upon the mirror at angles of incidence from 0 to 87 0 , for both s and p-polarizations. Measurements are obtained as a function of the diamond turning groove orientation with respect to the plane of incidence. Minimum absorptance at high angles of incidence is achieved with s-polarized light and with the grooves aligned parallel to the plane of incidence. The effects on the absorptance of a large scratch at glancing incidence are also described
Spherical neutron generator

Science.gov (United States)

Leung, Ka-Ngo

2006-11-21

A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.
U. S. Mirror Program

International Nuclear Information System (INIS)

Fowler, T.K.

1978-01-01

The mirror approach is now the principal alternate to the tokamak in the U.S. magnetic fusion energy program. The program is now focused on two new concepts that can obtain high values of Q, defined as the ratio of fusion power output to the neutral beam power injected to sustain the reaction. These are the tandem mirror and field reversed mirror concepts. Theoretically both concepts should be able to attain Q = 5 or more, as compared with Q approximately 1 in previous mirror designs. Success with either or both of these approaches would point the way toward fusion power plants with many attractive features. The linear geometry of mirror systems offers a distinct alternative to the toroidal tokamak. As a direct consequence of this difference in geometry, it is generally possible to build mirror systems in smaller units of modular construction that can probably be made to operate in steady-state. During the next 5 years the main mirror facilities in the U.S. will be the 2XIIB (renamed Beta II); a tandem mirror experiment caled TMX; and the Mirror Fusion Test Facility (MFTF) scheduled to be completed in 1981 at a cost of $94 million. As a background for discussing this program and mirror reactor concepts in later lectures, the current status of mirror physics will be reviewed by comparing theory and experimental data in four critical areas. These are adiabatic confinement of individual ions, electron heat losses out of the ends of the machine, the achievement of beta values of order unity; and stabilization of ''loss cone'' modes
The emergence of mirror-like response properties from domain-general principles in vision and audition.

Science.gov (United States)

Saygin, Ayse P; Dick, Frederic

2014-04-01

Like Cook et al., we suggest that mirror neurons are a fascinating product of cross-modal learning. As predicted by an associative account, responses in motor regions are observed for novel and/or abstract visual stimuli such as point-light and android movements. Domain-specific mirror responses also emerge as a function of audiomotor expertise that is slowly acquired over years of intensive training.
The mirror neuron system.

Science.gov (United States)

Cattaneo, Luigi; Rizzolatti, Giacomo

2009-05-01

Mirror neurons are a class of neurons, originally discovered in the premotor cortex of monkeys, that discharge both when individuals perform a given motor act and when they observe others perform that same motor act. Ample evidence demonstrates the existence of a cortical network with the properties of mirror neurons (mirror system) in humans. The human mirror system is involved in understanding others' actions and their intentions behind them, and it underlies mechanisms of observational learning. Herein, we will discuss the clinical implications of the mirror system.
Alignment and Distortion-Free Integration of Lightweight Mirrors into Meta-Shells for High-Resolution Astronomical X-Ray Optics

Science.gov (United States)

Chan, Kai-Wing; Zhang, William W.; Schofield, Mark J.; Numata, Ai; Mazzarella, James R.; Saha, Timo T.; Biskach, Michael P.; McCelland, Ryan S.; Niemeyer, Jason; Sharpe, Marton V.;

2016-01-01

High-resolution, high throughput optics for x-ray astronomy requires fabrication of well-formed mirror segments and their integration with arc-second level precision. Recently, advances of fabrication of silicon mirrors developed at NASA/Goddard prompted us to develop a new method of mirror integration. The new integration scheme takes advantage of the stiffer, more thermally conductive, and lower-CTE silicon, compared to glass, to build a telescope of much lighter weight. In this paper, we address issues of aligning and bonding mirrors with this method. In this preliminary work, we demonstrated the basic viability of such scheme. Using glass mirrors, we demonstrated that alignment error of 1" and bonding error 2" can be achieved for mirrors in a single shell. We will address the immediate plan to demonstrate the bonding reliability and to develop technology to build up a mirror stack and a whole "meta-shell".

MSFC Test Results for Selected Mirrors: Brush-Wellman/Goodrich 0.5 meter Joined-Beryllium Mirror; IABG 0.5 meter C/SiC Mirror; Xinetics 0.5 meter SiC Mirror; and Kodak 0.23 meter SiO2 Mirror

Science.gov (United States)

Hadaway, James; Blackwell, Lisa; Matthews, Gary; Eng, Ron; Stahl, Phil; Hraba, John; Thornton, Gary

2002-01-01

The results of cryo tests performed at the XRCF on the above mirrors will be presented. Each mirror was tested from room-temperature to around 30 K. The first three were tested together on a 3-mirror stand in the large chamber using the PhaseCam interferometer, while the Kodak mirror was tested in the small chamber using the EPI interferometer.
Progress towards sub-micron hard x-ray imaging using elliptically bent mirrors and its applications

International Nuclear Information System (INIS)

MacDowell, A.A.; Lamble, G.M.; Celestre, R.S.; Padmore, H.A.; Chang, C.H.; Patel, J.R.

1998-06-01

The authors have developed an x-ray micro-probe facility utilizing mirror bending techniques that allow white light x-rays (4--12keV) from the Advanced light Source Synchrotron to be focused down to spot sizes of micron spatial dimensions. They have installed a 4 crystal monochromator prior to the micro-focusing mirrors. The monochromator is designed such that it can move out of the way of the input beam, and allows the same micron sized sample to be illuminated with either white or monochromatic radiation. Illumination of the sample with white light allows for elemental mapping and Laue x-ray diffraction, while illumination of the sample with monochromatic light allows for elemental mapping (with reduced background), micro-X-ray absorption spectroscopy and micro-diffraction. The performance of the system will be described as will some of the initial experiments that cover the various disciplines of Earth, Material and Life Sciences
Progress towards sub-micron hard x-ray imaging using elliptically bent mirrors and its applications

Energy Technology Data Exchange (ETDEWEB)

MacDowell, A.A.; Lamble, G.M.; Celestre, R.S.; Padmore, H.A. [Lawrence Berkeley National Lab., CA (United States); Chang, C.H.; Patel, J.R. [Lawrence Berkeley National Lab., CA (United States). Advanced Light Source Div.]|[Stanford Univ., CA (United States)

1998-06-01

The authors have developed an x-ray micro-probe facility utilizing mirror bending techniques that allow white light x-rays (4--12keV) from the Advanced light Source Synchrotron to be focused down to spot sizes of micron spatial dimensions. They have installed a 4 crystal monochromator prior to the micro-focusing mirrors. The monochromator is designed such that it can move out of the way of the input beam, and allows the same micron sized sample to be illuminated with either white or monochromatic radiation. Illumination of the sample with white light allows for elemental mapping and Laue x-ray diffraction, while illumination of the sample with monochromatic light allows for elemental mapping (with reduced background), micro-X-ray absorption spectroscopy and micro-diffraction. The performance of the system will be described as will some of the initial experiments that cover the various disciplines of Earth, Material and Life Sciences.
Enhanced Interferometry with Programmable Spatial Light Modulator

Science.gov (United States)

2010-06-07

Interferometry, Spatial Light Modulator, Surface Accuracy, Optics, Mirror, Zernike , Freeform Optics, Null Testing, Hartman, Wavefront 16. SECURITY...S L M P ix e l- c a m Tilted Flat Mirror L a s e r PV. ± 3.4 λ -Tilt by the flat mirror, ~7 waves ~ 14 fringes Interferogram 3D view (Various...Interferogram ( 3D view) x- profile y- profile (Various waveplates and telescopes not shown) SLM can compensate tilted wavefronts with an accuracy of
Optical design and performance analysis of a 25 m class telescope with a segmented spherical primary

DEFF Research Database (Denmark)

Owner-Petersen, Mette

1996-01-01

The basic design and an analysis of the performance possibilities of a 25 m class optical telescope are presented here. The configuration consists of a 28 m segmented spherical primary M1 followed by three highly aspherical corrective mirrors M2, M3 and M4 which also deviate from cartesian shape...... sag and windbuffeting. Several types of aspherical figuring of M2, M3 and M4 all resulting in a field performance better than characterized by a RMS spotradius smaller than 0.1 arcseconds within a full FOV of 21 arcminutes are presented....
Light diffuseness metric, part 2 : Describing, measuring and visualizing the light flow and diffuseness in three-dimensional spaces

NARCIS (Netherlands)

Xia, L.; Pont, S.C.; Heynderickx, I.E.J.

2017-01-01

We introduce a way to simultaneously measure the light density, light vector and diffuseness of the light field using a cubic illumination meter based on the spherical harmonics representation of the light field. This approach was applied to six light probe images of natural scenes and four real
The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

International Nuclear Information System (INIS)

Simonen, T.; Cohen, R.; Correll, D.; Fowler, K.; Post, D.; Berk, H.; Horton, W.; Hooper, E.B.; Fisch, N.; Hassam, A.; Baldwin, D.; Pearlstein, D.; Logan, G.; Turner, B.; Moir, R.; Molvik, A.; Ryutov, D.; Ivanov, A.A; Kesner, J.; Cohen, B.; McLean, H.; Tamano, T.; Tang, X.Z.; Imai, T.

2008-01-01

Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT
The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

Energy Technology Data Exchange (ETDEWEB)

Simonen, T; Cohen, R; Correll, D; Fowler, K; Post, D; Berk, H; Horton, W; Hooper, E B; Fisch, N; Hassam, A; Baldwin, D; Pearlstein, D; Logan, G; Turner, B; Moir, R; Molvik, A; Ryutov, D; Ivanov, A A; Kesner, J; Cohen, B; McLean, H; Tamano, T; Tang, X Z; Imai, T

2008-10-24

Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT
Fabrication of an 8:1 ellipsoidal mirror for a synchrotron x-ray microprobe

International Nuclear Information System (INIS)

Jones, K.W.; Takacs, P.Z.; Hastings, J.B.; Casstevens, J.M.; Pionke, C.D.

1987-01-01

The fabrication of an 8:1 demagnifying ellipsoidal mirror to be used for an x-ray microprobe at the National Synchrotron Light Source X-26 beam port is described. The design aim was to produce a mirror that could be used over the photon energy range from about 3 to 17 keV. The 300-mm long mirror was required to operate at a grazing angle of 5 mr. The semimajor axis was 4500 mm and the semiminor axis 14.142 mm. Surface roughness of 1 nm or less and slope errors of 1 arc second parallel to the long axis and 200 arc seconds parallel to the short direction were specified. Production of the first electroless nickel-coated aluminum mirror using a diamond-turning technique has been completed. The mirror meets the 1 arc sec surface figure specification except for areas near the ends of the mirror. The reasons for these deviations arise from subtle details of the diamond-turning process which have not been fully incorporated in to the computer program that controls the diamond-turning machines. Further work in computer correction of repeatable errors of the diamond-turning machine can eliminate the waviness at the ends of the mirror. The diamond-turned mirror surface was not fully polished under this effort and therefore does not meet the roughness specification; however, surface smoothness of a fully polished cylindrical mirror manufactured using the same techniques does not meet the specification. It can be concluded that it is now technically feasible to meet the required specifications for the mirror and that the x-ray microprobe based on its use can be achieved
The construction and performance of a one-meter-long elliptically bent steel mirror

International Nuclear Information System (INIS)

Renner, T.R.; Franck, K.; Howells, M.R.; Irick, S.; Padmore, H.A.

1997-10-01

An elliptically bent mirror of total length 1.25 m has been developed at the Advanced Light Source (ALS) for focusing soft x-rays. The mirror is used to produce a small, high flux density illuminated field of view for a Photo Emission Electron Microscope (PEEM). The requirement to collect the maximum horizontal aperture with the need to highly demagnify the source leads to a mirror with a wide range of curvatures along the surface. This combined with the need to produce a low slope error surface at a reasonably low cost has required the authors to develop a mirror based on the controlled bending of a flat substrate. This is an extension of several other mirror projects at the ALS where controlled bending of glass and metal substrates has been used in microfocusing applications. Those mirrors however are a maximum of 200 mm long, and in this paper they describe the new challenges they have faced and the solutions they have adopted in developing a long and highly elliptical mirror. The mirror described here is manufactured from a low carbon steel (1006) which is capable of good dimensional stability, it is electroless nickel plated for polishing, and is bent into an elliptical shape by the application of unequal couples. They describe the mirror fabrication process, the mechanical details of the bending mechanism and the experimentally measured slope error from an ellipse. The final mirror has an rms roughness of 6 angstrom (rms), a full aperture (1.1 m) slope error of 14 microrad (rms), and a slope error of < 3 micro rad when optimized over approximately 2/3 of the required optical length (0.917 m)
Role of particle-hole symmetry in mirror energy difference

International Nuclear Information System (INIS)

Kumar, V.; Kumar, S.; Hasan, Z.; Kumar, D.; Koranga, B.S.; Rohitash; Singh, D.; Negi, D.; Angus, L.

2011-01-01

Charge symmetry between protons and neutrons means that they can be viewed as two states of the same particle, the nucleon, characterized by different projections of the isospin quantum number. In the hypothesis of charge symmetry expected identical behaviour of excited states of two nuclei with the same total number of nucleons (isobaric nuclei). The nuclei with magic number are considered to be spherical. When the number of particles/holes increase, the nucleus try towards more deformed upto mid-shell. It shows symmetry between particles and holes towards the deformation. The hypothesis of Particle-hole symmetry expected identical behaviour of excited states of two nuclei close to magic number. It is worthwhile to examine the shape of mirror energy difference (MED) close to magic number nuclei, which will also an example of particle-hole symmetry
Data Base for Light-Weight Automotive Diesel Power Plants. Volume 2: Discussion and Results.

Science.gov (United States)

1979-12-01

The effects on fuel economy, emissions, passenger car safety and other variables due to the installation of light-weight Diesel powerplants were studied. Experimental data was obtained on naturally aspirated and turbocharged Diesel engines installed ...
Longitudinal Analysis of Leptin Variation during Weight Regain after Weight Loss in Obese Children

DEFF Research Database (Denmark)

Holm, Jens-Christian; Gamborg, Michael; Ward, Leigh

2009-01-01

Objective: This study assessed if lower than predicted serum leptin concentrations seen during weight loss persisted during weight regain, with possible implications for weight control. Methods: 115 children were investigated during a 12-week weight loss program. 90 children completed the program....... Results: Children with the greatest increases in BMI standard deviation score (SDS) exhibited the largest leptin increments. The disproportionate reduction of leptin seen during weight loss recovered after weight loss. Leptin increases mirrored increases in BMI SDS during weight regain, and the leptin......-BMI SDS relationship seen during follow-up resembled the baseline leptin-BMI SDS relationship. Conclusion: Proportional increases of leptin and BMI SDS during weight regain suggests an intact leptin response during re-accumulation of fat. Following the pronounced reduction of leptin during weight loss...
[Depth of focus in spherical and aspheric intraocular lenses].

Science.gov (United States)

Nan, Li; Tang, Xin; Liu, Yong-ji

2012-02-01

To investigate depth of focus (DOF) in spherical and aspheric IOL eye models. Computer numerical simulation experiment was used. IOL eye model based on Liou-Brennan eye model was constructed by using ZEMAX optical design software. Different IOL were implanted in this eye model. Monochromatic through focus modulation transfer function (MTF) curves were computed. Pupil and aspheric designs' effect on DOF were analyzed. DOF of eye model increased with pupil shrinkage in 550 nm monochromatic light (FY60AD 1.20 D at 6 mm pupil, 1.35 D at 5 mm pupil, 1.70 D at 4 mm pupil, 2.46 D at 3 mm pupil; YA60BBR 1.24 D at 6 mm pupil, 1.48 D at 5 mm pupil, 1.80 D at 4 mm pupil, 2.50 D at 3 mm pupil). MTF in spherical IOL eye model was higher with minus defocus, this trend was obvious at larger pupil. MTF of aspheric IOL eyes were higher than spherical IOL eyes when well focused at 5 mm pupil, while the DOF was lower in aspheric IOL with negative spherical aberration (Tecnis Z9000 1.31 D, FY60AD 1.35 D, CeeOn911 1.55 D, YA60BBR 1.48 D). DOF decreased less in aspheric IOL with zero spherical aberration (LI61AO 1.42 D). DOF in IOL eye model was higher at smaller pupil. When the pupil was large, well focused aspheric IOL improved optical quality compared with spherical IOL, while DOF and the tolerance to defocus in aspheric IOL were partially lost; this phenomenon was obvious with minus defocus.
An Investigation of Damage Factors in Industrial Scale of Light-Weight Bricks Production

Directory of Open Access Journals (Sweden)

Dwi Wulandari Kiki

2017-01-01

Full Text Available A damage case of light weight brick’s production approximately at 6-7% of total production was found daily in one industry in East Jawa, Indonesia. The physical damage of product always occured. This paper investigates some factors that affect the lost in laboratory analysis. The analysis includes the chemical analysis of raw materials, reactivity of pozzolanic materials, and observation of strength based upon the position of light-weight bricks during autoclaving process. In addition, fly ash is introduced as mineral additive as one of the alternatives to improve the product’s quality. It is also concluded that grinding the silica sands particles is the optimum way to improve the quality, but the adding class F of fly ash to five percent in mixture is the most effective solution. Furthermore, maintaining quality of raw materials, curing process, and maintaining the machine will either reduce the product damage that occurred during the fabrication process in industry.
Spherical sampling

CERN Document Server

Freeden, Willi; Schreiner, Michael

2018-01-01

This book presents, in a consistent and unified overview, results and developments in the field of today´s spherical sampling, particularly arising in mathematical geosciences. Although the book often refers to original contributions, the authors made them accessible to (graduate) students and scientists not only from mathematics but also from geosciences and geoengineering. Building a library of topics in spherical sampling theory it shows how advances in this theory lead to new discoveries in mathematical, geodetic, geophysical as well as other scientific branches like neuro-medicine. A must-to-read for everybody working in the area of spherical sampling.
Development of micro-mirror slicer integral field unit for space-borne solar spectrographs

Science.gov (United States)

Suematsu, Yoshinori; Saito, Kosuke; Koyama, Masatsugu; Enokida, Yukiya; Okura, Yukinobu; Nakayasu, Tomoyasu; Sukegawa, Takashi

2017-12-01

We present an innovative optical design for image slicer integral field unit (IFU) and a manufacturing method that overcomes optical limitations of metallic mirrors. Our IFU consists of a micro-mirror slicer of 45 arrayed, highly narrow, flat metallic mirrors and a pseudo-pupil-mirror array of off-axis conic aspheres forming three pseudo slits of re-arranged slicer images. A prototype IFU demonstrates that the final optical quality is sufficiently high for a visible light spectrograph. Each slicer micro-mirror is 1.58 mm long and 30 μm wide with surface roughness ≤1 nm rms, and edge sharpness ≤ 0.1 μm, etc. This IFU is small size and can be implemented in a multi-slit spectrograph without any moving mechanism and fore optics, in which one slit is real and the others are pseudo slits from the IFU. The IFU mirrors were deposited by a space-qualified, protected silver coating for high reflectivity in visible and near IR wavelength regions. These properties are well suitable for space-borne spectrograph such as the future Japanese solar space mission SOLAR-C. We present the optical design, performance of prototype IFU, and space qualification tests of the silver coating.
Experimental Study of Reinforced Light Weight Concrete Beams

Directory of Open Access Journals (Sweden)

Hassanien Mohammed Thiyab

2016-12-01

Full Text Available This study provides a new technique for a lightweight concrete on one side and contribute to the application of sustainability principle by another side. The lightweight concrete was produced by replacing the coarse aggregate in the concrete mix by crushed bricks after conducting the sieve analysis process. To apply this technique to reinforced concrete beams, seven specimens having dimensions (1200 mm length × 200mm height × 100 mm width for each were poured. The first of these beams had made from ordinary concrete, and the rest lightweight different mix design as well as the casting of three cubes and a three-cylinder with each beam. After curing the specimens with water to the age 28 days, they were examined in the laboratory. Using different design mixes of concrete and with the help of super stabilizer material , good compressive strength of concrete was obtained so it become more effective lightweight in structure. By comparing between the results of the light and normal weight concrete beams, it is found reducing in the weight of concrete by about 23% due to using this technique ,the ultimate strength increased to about 32.1% and the deflection decreased about 46.7% .
All silicon waveguide spherical microcavity coupler device.

Science.gov (United States)

Xifré-Pérez, E; Domenech, J D; Fenollosa, R; Muñoz, P; Capmany, J; Meseguer, F

2011-02-14

A coupler based on silicon spherical microcavities coupled to silicon waveguides for telecom wavelengths is presented. The light scattered by the microcavity is detected and analyzed as a function of the wavelength. The transmittance signal through the waveguide is strongly attenuated (up to 25 dB) at wavelengths corresponding to the Mie resonances of the microcavity. The coupling between the microcavity and the waveguide is experimentally demonstrated and theoretically modeled with the help of FDTD calculations.
Differential Patterns of Dysconnectivity in Mirror Neuron and Mentalizing Networks in Schizophrenia

NARCIS (Netherlands)

Schilbach, Leonhard; Derntl, Birgit; Aleman, Andre; Caspers, Svenja; Clos, Mareike; Diederen, Kelly M J; Gruber, Oliver; Kogler, Lydia; Liemburg, Edith J; Sommer, Iris E; Müller, Veronika I; Cieslik, Edna C; Eickhoff, Simon B

Impairments of social cognition are well documented in patients with schizophrenia (SCZ), but the neural basis remains poorly understood. In light of evidence that suggests that the "mirror neuron system" (MNS) and the "mentalizing network" (MENT) are key substrates of intersubjectivity and joint

Determination of pitch rotation in a spherical birefringent microparticle

Science.gov (United States)

Roy, Basudev; Ramaiya, Avin; Schäffer, Erik

2018-03-01

Rotational motion of a three dimensional spherical microscopic object can happen either in pitch, yaw or roll fashion. Among these, the yaw motion has been conventionally studied using the intensity of scattered light from birefringent microspheres through crossed polarizers. Up until now, however, there is no way to study the pitch motion in spherical microspheres. Here, we suggest a new method to study the pitch motion of birefringent microspheres under crossed polarizers by measuring the 2-fold asymmetry in the scattered signal either using video microscopy or with optical tweezers. We show a couple of simple examples of pitch rotation determination using video microscopy for a microsphere attached with a kinesin molecule while moving along a microtubule and of a particle diffusing freely in water.
Substrate and coating defect planarization strategies for high-laser-fluence multilayer mirrors

International Nuclear Information System (INIS)

Stolz, Christopher J.; Wolfe, Justin E.; Mirkarimi, Paul B.; Folta, James A.; Adams, John J.; Menor, Marlon G.; Teslich, Nick E.; Soufli, Regina; Menoni, Carmen S.; Patel, Dinesh

2015-01-01

Planarizing or smoothing over nodular defects in multilayer mirrors can be accomplished by a discrete deposit-and-etch process that exploits the angle-dependent etching rate of optical materials. Typically, nodular defects limit the fluence on mirrors irradiated at 1064 nm with 10 ns pulse lengths due to geometrically- and interference-induced light intensification. Planarized hafina/silica multilayer mirrors have demonstrated > 125 J/cm 2 laser resistance for single-shot testing and 50 J/cm 2 for multi-shot testing for nodular defects originating on the substrate surface. Two planarization methods were explored: thick planarization layers on the substrate surface and planarized silica layers throughout the multilayer in which only the silica layers that are below one half of the incoming electric field value are etched. This paper also describes the impact of planarized defects that are buried within the multilayer structure compared to planarized substrate particulate defects. - Highlights: • Defect planarization significantly improves multilayer mirror laser resistance • Substrate and coating defects have both been effectively planarized • Single and multishot laser resistance improvement was demonstrated
Plasma heating and hot ion sustaining in mirror based hybrids

International Nuclear Information System (INIS)

Moiseenko, V. E.; Ågren, O.

2012-01-01

Possibilities of plasma heating and sloshing ion sustaining in mirror based hybrids are briefly reviewed. Sloshing ions, i.e. energetic ions with a velocity distribution concentrated to a certain pitch-angle, play an important role in plasma confinement and generation of fusion neutrons in mirror machines. Neutral beam injection (NBI) is first discussed as a method to generate sloshing ions. Numerical results of NBI modeling for a stellarator-mirror hybrid are analyzed. The sloshing ions could alternatively be sustained by RF heating. Fast wave heating schemes, i.e. magnetic beach, minority and second harmonic heating, are addressed and their similarities and differences are described. Characteristic features of wave propagation in mirror hybrid devices including both fundamental harmonic minority and second harmonic heating are examined. Minority heating is efficient for a wide range of minority concentration and plasma densities; it allows one to place the antenna aside from the hot ion location. A simple-design strap antenna suitable for this has good performance. However, this scenario is appropriate only for light minority ions. The second harmonic heating can be applied for the heavy ion component. Arrangements are similar for minority and second harmonic heating. The efficiency of second harmonic heating is influenced by a weaker wave damping than for minority heating. Numerical calculations show that in a hybrid reactor scaled mirror machine the deuterium sloshing ions could be heated within the minority heating scheme, while the tritium ions could be sustained by second harmonic heating.
Clinical characteristics of mirror syndrome: a comparison of 10 cases of mirror syndrome with non-mirror syndrome fetal hydrops cases.

Science.gov (United States)

Hirata, Go; Aoki, Shigeru; Sakamaki, Kentaro; Takahashi, Tsuneo; Hirahara, Fumiki; Ishikawa, Hiroshi

2016-01-01

To investigate clinical features of mirror syndrome. We retrospectively reviewed 71 cases of fetal hydrops with or without mirror syndrome, and compared with respect to maternal age, the body mass index, the primipara rate, the gestational age at delivery, the timing of fetal hydrops onset, the severity of fetal edema, placental swelling, the laboratory data and the fetal mortality. The data are expressed as the medians. Mirror syndrome developed in 29% (10/35) of the cases with fetal hydrops. In mirror group, the onset time of fetal hydrops was significantly earlier (29 weeks versus 31 weeks, p = 0.011), and the severity of fetal hydrops (fetal edema/biparietal diameter) was significantly higher than non-mirror group (0.23 versus 0.16, p < 0.001). There was significantly higher serum human chorionic gonadotropin (hCG) (453,000 IU/L versus 80,000 IU/L, p < 0.001) and lower hemoglobin (8.9 g/dL versus 10.1 g/dL, p =0.002), hypoalbuminemia (2.3 mg/dL versus 2.7 mg/dL, p = 0.007), hyperuricemia (6.4 mg/dL versus 5.0 mg/dL, p = 0.043) in mirror group. Mirror syndrome is occurred frequently in early and severe fetal hydrops and cause hemodilution and elevation of serum hCG.
Small mirror fusion reactors

International Nuclear Information System (INIS)

Carlson, G.A.; Schultz, K.R.; Smith, A.C. Jr.

1978-01-01

Basic requirements for the pilot plants are that they produce a net product and that they have a potential for commercial upgrade. We have investigated a small standard mirror fusion-fission hybrid, a two-component tandem mirror hybrid, and two versions of a field-reversed mirror fusion reactor--one a steady state, single cell reactor with a neutral beam-sustained plasma, the other a moving ring field-reversed mirror where the plasma passes through a reaction chamber with no energy addition
Present status of operation of the ETE spherical tokamak

International Nuclear Information System (INIS)

Bosco, E. del; Berni, L.A.; Ferreira, J.G.; Oliveira, R.M.; Ludwig, G.O.; Shibata, C.S.

2005-01-01

The ETE is a spherical tokamak with aspect ratio A = 1.5 (major radius of 0.3m and minor radius of 0.2m) under development at LAP/INPE. The ETE incorporates some innovative features that resulted in a compact and light weighted device with good plasma accessibility. Since the first plasma obtained at the very end of 2000 (Ip = 12kA, duration of 2ms, B o = 0.1T), the machine is operational and improvements are being done in order to achieve the planned final parameter values for the first phase of operation (Ip = 220kA, duration 15ms, B o = 0.4T), which are limited by the available capacitors. The efforts are being focused on incrementing the energy of the capacitor banks, lessening the stray magnetic fields in the plasma region, conditioning the vacuum vessel wall, implementing diagnostics and optimizing the discharge parameters. Presently, plasma currents in the range of 40-60kA (duration of 6-12 ms) are routinely obtained. Electron temperatures up to 160eV and plasma densities up to 3.0x10 19 m -3 are being reached. (author)
Cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror

International Nuclear Information System (INIS)

Yuan Sheng; Goldberg, Kenneth A.; Yashchuk, Valeriy V.; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory; Macdougall, James; Mochi, Iacopo; Warwick, Tony

2011-01-01

At the Advanced Light Source (ALS), we are developing broadly applicable, high-accuracy, in-situ, at-wavelength wavefront slope measurement techniques for Kirkpatrick-Baez (KB) mirror nano-focusing. In this paper, we report an initial cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror. This cross-check provides a validation of the in-situ shearing interferometry, currently under development at the ALS.
Dim light at night disrupts molecular circadian rhythms and increases body weight.

Science.gov (United States)

Fonken, Laura K; Aubrecht, Taryn G; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

2013-08-01

With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.
Gender differences in the mu rhythm of the human mirror-neuron system.

Science.gov (United States)

Cheng, Yawei; Lee, Po-Lei; Yang, Chia-Yen; Lin, Ching-Po; Hung, Daisy; Decety, Jean

2008-05-07

Psychologically, females are usually thought to be superior in interpersonal sensitivity than males. The human mirror-neuron system is considered to provide the basic mechanism for social cognition. However, whether the human mirror-neuron system exhibits gender differences is not yet clear. We measured the electroencephalographic mu rhythm, as a reliable indicator of the human mirror-neuron system activity, when female (N = 20) and male (N = 20) participants watched either hand actions or a moving dot. The display of the hand actions included androgynous, male, and female characteristics. The results demonstrate that females displayed significantly stronger mu suppression than males when watching hand actions. Instead, mu suppression was similar across genders when participants observed the moving dot and between the perceived sex differences (same-sex vs. opposite-sex). In addition, the mu suppressions during the observation of hand actions positively correlated with the personal distress subscale of the interpersonal reactivity index and negatively correlated with the systemizing quotient. The present findings indirectly lend support to the extreme male brain theory put forward by Baron-Cohen (2005), and may cast some light on the mirror-neuron dysfunction in autism spectrum disorders. The mu rhythm in the human mirror-neuron system can be a potential biomarker of empathic mimicry.
MISR Dark Water aerosol retrievals: operational algorithm sensitivity to particle non-sphericity

Directory of Open Access Journals (Sweden)

O. V. Kalashnikova

2013-08-01

Full Text Available The aim of this study is to theoretically investigate the sensitivity of the Multi-angle Imaging SpectroRadiometer (MISR operational (version 22 Dark Water retrieval algorithm to aerosol non-sphericity over the global oceans under actual observing conditions, accounting for current algorithm assumptions. Non-spherical (dust aerosol models, which were introduced in version 16 of the MISR aerosol product, improved the quality and coverage of retrievals in dusty regions. Due to the sensitivity of the retrieval to the presence of non-spherical aerosols, the MISR aerosol product has been successfully used to track the location and evolution of mineral dust plumes from the Sahara across the Atlantic, for example. However, the MISR global non-spherical aerosol optical depth (AOD fraction product has been found to have several climatological artifacts superimposed on valid detections of mineral dust, including high non-spherical fraction in the Southern Ocean and seasonally variable bands of high non-sphericity. In this paper we introduce a formal approach to examine the ability of the operational MISR Dark Water algorithm to distinguish among various spherical and non-spherical particles as a function of the variable MISR viewing geometry. We demonstrate the following under the criteria currently implemented: (1 Dark Water retrieval sensitivity to particle non-sphericity decreases for AOD below about 0.1 primarily due to an unnecessarily large lower bound imposed on the uncertainty in MISR observations at low light levels, and improves when this lower bound is removed; (2 Dark Water retrievals are able to distinguish between the spherical and non-spherical particles currently used for all MISR viewing geometries when the AOD exceeds 0.1; (3 the sensitivity of the MISR retrievals to aerosol non-sphericity varies in a complex way that depends on the sampling of the scattering phase function and the contribution from multiple scattering; and (4 non-sphericity
Development and Control of a Three-Axis Satellite Simulator for the Bifocal Relay Mirror Initiative

National Research Council Canada - National Science Library

Chernesky, Vincent

2001-01-01

.... The bifocal relay mirror spacecraft system is composed of two optically coupled telescopes used to redirect the laser light from ground-based, aircraft-based or spacecraft based lasers to distant...
Large aperture telescope technology: a design for an active lightweight multi-segmented fold-out space mirror

Science.gov (United States)

Thompson, S. J.; Doel, A. P.; Whalley, M.; Edeson, R.; Edeson, R.; Tosh, I.; Poyntz-Wright, O.; Atad-Ettedgui, E.; Montgomery, D.; Nawasra, J.

2017-11-01

Large aperture telescope technology (LATT) is a design study for a differential lidar (DIAL) system; the main investigation being into suitable methods, technologies and materials for a 4-metre diameter active mirror that can be stowed to fit into a typical launch vehicle (e.g. ROKOT launcher with 2.1-metre diameter cargo) and can self-deploy - in terms of both leaving the space vehicle and that the mirrors unfold and self-align to the correct optical form within the tolerances specified. The primary mirror requirements are: main wavelength of 935.5 nm, RMS corrected wavefront error of λ/6, optical surface roughness better than 5 nm, areal density of less than 16 kg/m2 and 1-2 mirror shape corrections per orbit. The primary mirror consists of 7 segments - a central hexagonal mirror and 6 square mirror petals which unfold to form the 4-meter diameter aperture. The focus of the UK LATT consortium for this European Space Agency (ESA) funded project is on using lightweighted aluminium or carbon-fibre-composite materials for the mirror substrate in preference to more traditional materials such as glass and ceramics; these materials have a high strength and stiffness to weight ratio, significantly reducing risk of damage due to launch forces and subsequent deployment in orbit. We present an overview of the design, which includes suitable actuators for wavefront correction, petal deployment mechanisms and lightweight mirror technologies. Preliminary testing results from manufactured lightweight mirror samples will also be summarised.
Radiative Transfer Equation for Anisotropic Spherical Medium with Specular Reflective Index

International Nuclear Information System (INIS)

Elghazaly, A.

2009-01-01

Radiative transfer problem for anisotropic scattering in a spherical homogeneous, turbid medium with diffuse and angular dependent (specular) reflecting boundaries is solved using the Pomraning-Eddington approximation method. The angular dependent specular reflectivity of the boundary is considered as Fresnel's reflection probability function. The partial heat flux is calculated with anisotropic scattering through a homogeneous solid sphere. The calculations are carried out for spherical media of radii 0.1, 1.0, and 10 mfp and for different scattering albedo. Two different weight functions are used to verify the boundary conditions. Our results are compared with the available data and give an excellent agreement for thick and highly scattering media
Bronze rainbow hologram mirrors

Science.gov (United States)

Dawson, P.

2006-02-01

This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.
Position control of ECRH launcher mirrors by laser speckle sensor

International Nuclear Information System (INIS)

Michelsen, Poul K.; Bindslev, Henrik; Hansen, Rene Skov; Hanson, Steen G.

2003-01-01

The planned ECRH system for JET included several fixed and steerable mirrors some of which should have been fixed to the building structure and some to the JET vessel structure. A similar system may be anticipated for ITER and for other fusion devices in the future. In order to have high reproducibility of the ECRH beam direction, it is necessary to know the exact positions of the mirrors. This is not a trivial problem because of thermal expansion of the vessel structures and of the launcher itself and of its support structure, the mechanical load on mirrors and support structures, and the accessibility to the various mirrors. We suggest to use a combination of infrared diagnostic of beam spot positions and a new technique published recently, which is based on a non-contact laser speckle sensor for measuring one- and two-dimensional angular displacement. The method is based on Fourier transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped onto an array image sensor placed in the Fourier plane. Measuring the displacement of this so-called speckle pattern facilitates the determination of the mirror orientation. Transverse target movement can be measured by observing the speckle movement in the image plane of the object. No special surface treatment is required for surfaces having irregularities of the order of or larger than the wavelength of the incident light. For the JET ECRH launcher it is mainly for the last mirror pointing towards the plasma where the technique may be useful. This mirror has to be steerable in order to reflect the microwave beam in the correct direction towards the plasma. Maximum performance of the microwave heating requires that the beam hits this mirror at its centre and that the mirror is turned in the correct angle. Inaccuracies in the positioning of the pull rods for controlling the mirror turning and thermal effects makes it
Diffuse mirrors: 3D reconstruction from diffuse indirect illumination using inexpensive time-of-flight sensors

KAUST Repository

Heide, Felix

2014-06-01

The functional difference between a diffuse wall and a mirror is well understood: one scatters back into all directions, and the other one preserves the directionality of reflected light. The temporal structure of the light, however, is left intact by both: assuming simple surface reflection, photons that arrive first are reflected first. In this paper, we exploit this insight to recover objects outside the line of sight from second-order diffuse reflections, effectively turning walls into mirrors. We formulate the reconstruction task as a linear inverse problem on the transient response of a scene, which we acquire using an affordable setup consisting of a modulated light source and a time-of-flight image sensor. By exploiting sparsity in the reconstruction domain, we achieve resolutions in the order of a few centimeters for object shape (depth and laterally) and albedo. Our method is robust to ambient light and works for large room-sized scenes. It is drastically faster and less expensive than previous approaches using femtosecond lasers and streak cameras, and does not require any moving parts.
Diffuse mirrors: 3D reconstruction from diffuse indirect illumination using inexpensive time-of-flight sensors

KAUST Repository

Heide, Felix; Xiao, Lei; Heidrich, Wolfgang; Hullin, Matthias B.

2014-01-01

The functional difference between a diffuse wall and a mirror is well understood: one scatters back into all directions, and the other one preserves the directionality of reflected light. The temporal structure of the light, however, is left intact by both: assuming simple surface reflection, photons that arrive first are reflected first. In this paper, we exploit this insight to recover objects outside the line of sight from second-order diffuse reflections, effectively turning walls into mirrors. We formulate the reconstruction task as a linear inverse problem on the transient response of a scene, which we acquire using an affordable setup consisting of a modulated light source and a time-of-flight image sensor. By exploiting sparsity in the reconstruction domain, we achieve resolutions in the order of a few centimeters for object shape (depth and laterally) and albedo. Our method is robust to ambient light and works for large room-sized scenes. It is drastically faster and less expensive than previous approaches using femtosecond lasers and streak cameras, and does not require any moving parts.
Finite element simulation of a novel composite light-weight microporous cladding panel

Science.gov (United States)

Tian, Lida; Wang, Dongyan

2018-04-01

A novel composite light-weight microporous cladding panel with matched connection detailing is developed. Numerical simulation on the experiment is conducted by ABAQUS. The accuracy and rationality of the finite element model is verified by comparison between the simulation and the experiment results. It is also indicated that the novel composite cladding panel is of desirable bearing capacity, stiffness and deformability under out-of-plane load.
Interface characterization in B-based multilayer mirrors for next generation lithography

International Nuclear Information System (INIS)

Naujok, Philipp; Yulin, Sergiy; Müller, Robert; Kaiser, Norbert; Tünnermann, Andreas

2016-01-01

The interfaces in La/B_4C and LaN/B_4C multilayer mirrors designed for near normal incidence reflection of 6.x nm EUV light were investigated by grazing incidence X-ray reflectometry, high-resolution transmission electron microscopy and EUV reflectometry. The thickness and roughness asymmetries of the different interfaces in both studied systems have been identified. A development of interface roughness with an increasing number of bilayers was found by different investigation methods. For near normal incidence, R = 51.1% @ λ = 6.65 nm could be reached with our La/B_4C multilayer mirrors, whereas R = 58.1% was achieved with LaN/B_4C multilayers at the same wavelength. - Highlights: • Interface structure in B-based multilayer mirrors investigated. • Combining X-ray reflection, EUV reflection and transmission electron microscopy • Interface thickness and roughness asymmetry identified • Interface roughness increases with higher number of bilayers.
Spherical Bessel transform via exponential sum approximation of spherical Bessel function

Science.gov (United States)

Ikeno, Hidekazu

2018-02-01

A new algorithm for numerical evaluation of spherical Bessel transform is proposed in this paper. In this method, the spherical Bessel function is approximately represented as an exponential sum with complex parameters. This is obtained by expressing an integral representation of spherical Bessel function in complex plane, and discretizing contour integrals along steepest descent paths and a contour path parallel to real axis using numerical quadrature rule with the double-exponential transformation. The number of terms in the expression is reduced using the modified balanced truncation method. The residual part of integrand is also expanded by exponential functions using Prony-like method. The spherical Bessel transform can be evaluated analytically on arbitrary points in half-open interval.

Uniqueness of flat spherically symmetric spacelike hypersurfaces admitted by spherically symmetric static spacetimes

Science.gov (United States)

Beig, Robert; Siddiqui, Azad A.

2007-11-01

It is known that spherically symmetric static spacetimes admit a foliation by flat hypersurfaces. Such foliations have explicitly been constructed for some spacetimes, using different approaches, but none of them have proved or even discussed the uniqueness of these foliations. The issue of uniqueness becomes more important due to suitability of flat foliations for studying black hole physics. Here, flat spherically symmetric spacelike hypersurfaces are obtained by a direct method. It is found that spherically symmetric static spacetimes admit flat spherically symmetric hypersurfaces, and that these hypersurfaces are unique up to translation under the timelike Killing vector. This result guarantees the uniqueness of flat spherically symmetric foliations for such spacetimes.
Mirror Fusion Test Facility: an intermediate device to a mirror fusion reactor

International Nuclear Information System (INIS)

Karpenko, V.N.

1983-01-01

The Mirror Fusion Test Facility (MFTF-B) now under construction at Lawrence Livermore National Laboratory represents more than an order-of-magnitude step from earlier magnetic-mirror experiments toward a future mirror fusion reactor. In fact, when the device begins operating in 1986, the Lawson criteria of ntau = 10 14 cm -3 .s will almost be achieved for D-T equivalent operation, thus signifying scientific breakeven. Major steps have been taken to develop MFTF-B technologies for tandem mirrors. Steady-state, high-field, superconducting magnets at reactor-revelant scales are used in the machine. The 30-s beam pulses, ECRH, and ICRH will also introduce steady-state technologies in those systems
Towards a Light-weight Bag-of-tasks Grid Architecture

Directory of Open Access Journals (Sweden)

I. Bašičević

2015-06-01

Full Text Available The paper presents the application of SIP protocol in the context of bag-of-tasks grid architecture. The SIP protocol has been used in the realization of the execution management service. The main idea is the use of stateful SIP proxy as a request broker. The paper provides a description of the concept, and the prototype system that has been built, as well as the calculation of estimated performance level and its relation to maximum RTT of grid system. The main advantage of this light-weight grid architecture is the reuse of a mature infrastructure. A short overview of some approaches to the mathematical modeling of computer grids is included.
Mirror plasma apparatus

International Nuclear Information System (INIS)

Moir, R.W.

1981-01-01

A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma
Mesmerising mirror neurons.

Science.gov (United States)

Heyes, Cecilia

2010-06-01

Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition. Copyright 2010 Elsevier Inc. All rights reserved.
Stress Measurement by Geometrical Optics

Science.gov (United States)

Robinson, R. S.; Rossnagel, S. M.

1986-01-01

Fast, simple technique measures stresses in thin films. Sample disk bowed by stress into approximately spherical shape. Reflected image of disk magnified by amount related to curvature and, therefore, stress. Method requires sample substrate, such as cheap microscope cover slide, two mirrors, laser light beam, and screen.
Geometry of mirror manifolds

International Nuclear Information System (INIS)

Aspinwall, P.S.; Luetken, C.A.

1991-01-01

We analyze the mirror manifold hypothesis in one and three dimensions using the simplest available representations of the N = 2 superconformal algebra. The symmetries of these tensor models can be divided out to give an explicit representation of the mirror, and we give a simple group theoretical algorithm for determining which symmetries should be used. We show that the mirror of a superconformal field theory does not always have a geometrical interpretation, but when it does, deformations of complex structure of one manifold are reflected in deformations of the Kaehler form of the mirror manifold, and we show how the large radius limit of a manifold corresponds to a large complex structure limit in the mirror manifold. The mirror of the Tian-Yau three generation model is constructed both as a conformal field theory and as an algebraic variety with Euler number six. The Hodge numbers of this manifolds are fixed, but the intersection numbes are highly ambiguous, presumably reflected a rich structure of multicritical points in the moduli space of the field theory. (orig.)
Analyses of metallic first mirror samples after long term plasma exposure in Tore Supra

International Nuclear Information System (INIS)

Lipa, M.; Schunke, B.; Gil, Ch.; Bucalossi, J.; Voitsenya, V.S.; Konovalov, V.; Vukolov, K.; Balden, M.; De Temmerman, G.; Oelhafen, P.; Litnovsky, A.; Wienhold, P.

2006-01-01

Metallic mirrors are foreseen in ITER diagnostic systems as optical elements directly viewing the plasma radiation. In the frame of an EFDA contract, metallic mirror samples have been exposed for long pulse plasma discharges in Tore Supra (TS) in order to investigate surface modifications caused by erosion and re-deposition processes. Three different materials have been selected: mono-crystalline molybdenum (mc-Mo), polycrystalline stainless steel (SS) and copper (Cu). The mc-Mo samples showed after TS exposure almost no surface roughness modifications and the lowest net-erosion. A slight reflectivity reduction, most pronounced in the near UV, is attributed to light absorption in a thin carbon deposit. Cu mirrors showed by far the highest surface roughness, erosion and diffusive reflectivity. Comparative laboratory glow discharge experiments with virgin reference samples and numerical simulations of erosion/deposition confirm the dominant contribution of conditioning procedures to erosion of mirrors exposed (without shutter protection) in Tore Supra
Potential Sources of Polarized Light from a Plant Canopy

Science.gov (United States)

Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

2016-01-01

Field measurements have demonstrated that sunlight polarized during a first surface reflection by shiny leaves dominates the optical polarization of the light reflected by shiny-leafed plant canopies having approximately spherical leaf angle probability density functions ("Leaf Angle Distributions" - LAD). Yet for other canopies - specifically those without shiny leaves and/or spherical LADs - potential sources of optically polarized light may not always be obvious. Here we identify possible sources of polarized light within those other canopies and speculate on the ecologically important information polarization measurements of those sources might contain.
Mirror coatings for large aperture UV optical infrared telescope optics

Science.gov (United States)

Balasubramanian, Kunjithapatham; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Del Hoyo, Javier; Quijada, Manuel

2017-09-01

Large space telescope concepts such as LUVOIR and HabEx aiming for observations from far UV to near IR require advanced coating technologies to enable efficient gathering of light with important spectral signatures including those in far UV region down to 90nm. Typical Aluminum mirrors protected with MgF2 fall short of the requirements below 120nm. New and improved coatings are sought to protect aluminum from oxidizing readily in normal environment causing severe absorption and reduction of reflectance in the deep UV. Choice of materials and the process of applying coatings present challenges. Here we present the progress achieved to date with experimental investigations of coatings at JPL and at GSFC and discuss the path forward to achieve high reflectance in the spectral region from 90 to 300nm without degrading performance in the visible and NIR regions taking into account durability concerns when the mirrors are exposed to normal laboratory environment as well as high humidity conditions. Reflectivity uniformity required on these mirrors is also discussed.
Optimal alignment of mirror based pentaprisms for scanning deflectometric devices

Energy Technology Data Exchange (ETDEWEB)

Barber, Samuel K.; Geckeler, Ralf D.; Yashchuk, Valeriy V.; Gubarev, Mikhail V.; Buchheim, Jana; Siewert, Frank; Zeschke, Thomas

2011-03-04

In the recent work [Proc. of SPIE 7801, 7801-2/1-12 (2010), Opt. Eng. 50(5) (2011), in press], we have reported on improvement of the Developmental Long Trace Profiler (DLTP), a slope measuring profiler available at the Advanced Light Source Optical Metrology Laboratory, achieved by replacing the bulk pentaprism with a mirror based pentaprism (MBPP). An original experimental procedure for optimal mutual alignment of the MBPP mirrors has been suggested and verified with numerical ray tracing simulations. It has been experimentally shown that the optimally aligned MBPP allows the elimination of systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of the bulk pentaprism. In the present article, we provide the analytical derivation and verification of easily executed optimal alignment algorithms for two different designs of mirror based pentaprisms. We also provide an analytical description for the mechanism for reduction of the systematic errors introduced by a typical high quality bulk pentaprism. It is also shown that residual misalignments of an MBPP introduce entirely negligible systematic errors in surface slope measurements with scanning deflectometric devices.
Mirror systems.

Science.gov (United States)

Fogassi, Leonardo; Ferrari, Pier Francesco

2011-01-01

Mirror neurons are a class of visuomotor neurons, discovered in the monkey premotor cortex and in an anatomically connected area of the inferior parietal lobule, that activate both during action execution and action observation. They constitute a circuit dedicated to match actions made by others with the internal motor representations of the observer. It has been proposed that this matching system enables individuals to understand others' behavior and motor intentions. Here we will describe the main features of mirror neurons in monkeys. Then we will present evidence of the presence of a mirror system in humans and of its involvement in several social-cognitive functions, such as imitation, intention, and emotion understanding. This system may have several implications at a cognitive level and could be linked to specific social deficits in humans such as autism. Recent investigations addressed the issue of the plasticity of the mirror neuron system in both monkeys and humans, suggesting also their possible use in rehabilitation. WIREs Cogn Sci 2011 2 22-38 DOI: 10.1002/wcs.89 For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.
Mirror symmetry, mirror map and applications to complete intersection Calabi-Yau spaces

CERN Document Server

Hosono, S.; Theisen, S.; Yau, Shing-Tung

1995-01-01

We extend the discussion of mirror symmetry, Picard-Fuchs equations, instanton corrected Yukawa couplings and the topological one loop partition function to the case of complete intersections with higher dimensional moduli spaces. We will develop a new method of obtaining the instanton corrected Yukawa couplings through a study of the solutions of the Picard-Fuchs equations. This leads to closed formulas for the prepotential for the K\\"ahler moduli fields induced from the ambient space for all complete intersections in nonsingular weighted projective spaces. As examples we treat part of the moduli space of the phenomenologically interesting three generation models which are found in this class. We also apply our method to solve the simplest model in which topology change was observed and discuss examples of complete intersections in singular ambient spaces.
Investigation of surface homogeneity of mirrors for the CBM-RICH detector and low-mass di-electron feasibility studies

International Nuclear Information System (INIS)

Lebedeva, E; Hoehne, C

2014-01-01

The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate high net-baryon density matter at moderate temperatures in A+A collisions from 4-45 AGeV. One of the key observables of the CBM physics program is electromagnetic radiation as a probe of strongly interacting matter in heavy-ion collisions, carrying undistorted information on its conditions to the detector. This includes detailed investigations of low-mass vector mesons in their di-electron channel. A clean and efficient identification of electrons is required for such measurements. In CBM the electron identification will be performed by a Ring Imaging Cherenkov detector and several layers of Transition Radiation Detectors. The RICH detector will be operated with CO 2 radiator gas, MAPMTs as photodetector and spherical glass mirrors as focusing elements. A high quality of the mirrors in terms of reflectivity and surface homogeneity is required. In the first part of the contribution results on measurements of the mirror surface homogeneity are presented. Results on the feasibility studies of low-mass di-electron measurements with realistic detector response are discussed in the second part of the contribution.
First results of spherical GEMs

CERN Document Server

Pinto, Serge Duarte; Brock, Ian; Croci, Gabriele; David, Eric; de Oliveira, Rui; Ropelewski, Leszek; van Stenis, Miranda; Taureg, Hans; Villa, Marco

2010-01-01

We developed a method to make GEM foils with a spherical geometry. Tests of this procedure and with the resulting spherical GEMs are presented. Together with a spherical drift electrode, a spherical conversion gap can be formed. This eliminates the parallax error for detection of x-rays, neutrons or UV photons when a gaseous converter is used. This parallax error limits the spatial resolution at wide scattering angles. Besides spherical GEMs, we have developed curved spacers to maintain accurate spacing, and a conical field cage to prevent edge distortion of the radial drift field up to the limit of the angular acceptance of the detector. With these components first tests are done in a setup with a spherical entrance window but a planar readout structure; results will be presented and discussed. A flat readout structure poses difficulties, however. Therefore we will show advanced plans to make a prototype of an entirely spherical double-GEM detector, including a spherical 2D readout structure. This detector w...
Catadioptric aberration correction in cathode lens microscopy

Energy Technology Data Exchange (ETDEWEB)

Tromp, R.M. [IBM T.J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598 (United States); Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

2015-04-15

In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed.
Design and performance of capping layers for extreme-ultraviolet multilayer mirrors

International Nuclear Information System (INIS)

Bajt, Sasa; Chapman, Henry N.; Nguyen, Nhan; Alameda, Jennifer; Robinson, Jeffrey C.; Malinowski, Michael; Gullikson, Eric; Aquila, Andrew; Tarrio, Charles; Grantham, Steven

2003-01-01

Multilayer lifetime has emerged as one of the major issues for the commercialization of extreme-ultraviolet lithography (EUVL). We describe the performance of an oxidation-resistant capping layer of Ru atop multilayers that results in a reflectivity above 69% at 13.2 nm, which is suitable for EUVL projection optics and has been tested with accelerated electron-beam and extreme-ultraviolet (EUV) light in a water-vapor environment. Based on accelerated exposure results, we calculated multilayer lifetimes for all reflective mirrors in a typical commercial EUVL tool and concluded that Ru-capped multilayers have ∼40x longer lifetimes than Si-capped multilayers, which translates to 3 months to many years, depending on the mirror dose
Method of neutronic calculations for a spherical cell equivalent to cylindrical one for using computer codes in light water reactors in the fluidized bed nuclear reactor

International Nuclear Information System (INIS)

Borges, V.; Sefidvash, F.; Rastogi, E.P.; Huria, H.C.; Krishnani, P.D.

1989-01-01

In order to use the existing light water reactor cell calculation codes for fluidized bed nuclear reactor having spherical fuel cells, an equivalence method has been developed. This method is shown to be adequate in calculation of the Dancoff factor. This method also was applicable in LEOPARD code and the results obtained in calculation of K ∞ was compared with the obtained using the DTF IV code, the results showed that the method is adequate for the calculations neutronics of the fluidized bed nuclear reactor. (author) [pt
Gasdynamic Mirror Fusion Propulsion Experiment

Science.gov (United States)

Emrich, Bill; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust producing plasma. Currently, the MSFC GDM is constructed in three segments. The vacuum chamber mirror segment, the plasma injector mirror segment, and the main plasma chamber segment. Enough magnets are currently available to construct up to three main plasma chamber segments. The mirror segments are also segmented such that they can be expanded to accommodate new end plugging strategies with out requiring the disassembly of the entire mirror segment. The plasma for the experiment is generated in a microwave cavity located between the main magnets and the mirror magnets. Ion heating is accomplished through ambipolar diffusion. The objective of the experiment is to investigate the stability characteristics of the gasdynamic mirror and to map a region of parameter space within which the plasma can be confined in a stable steady state configuration. The mirror ratio, plasma density, and plasma "b" will be varied over a range of values and measurements subsequently taken to determine the degree of plasma stability.
Review of mirror fusion reactor designs

International Nuclear Information System (INIS)

Bender, D.J.

1977-01-01

Three magnetic confinement concepts, based on the mirror principle, are described. These mirror concepts are summarized as follows: (1) fusion-fission hybrid reactor, (2) tandem mirror reactor, and (3) reversed field mirror reactor

New method for determining the light travel time in static, spherically symmetric spacetimes. Calculation of the terms of order G3

International Nuclear Information System (INIS)

Linet, Bernard; Teyssandier, Pierre

2013-01-01

A new iterative method for calculating the travel time of a photon as a function of the spatial positions of the emitter and the receiver in the field of a static, spherically symmetric body is presented. The components of the metric are assumed to be expressible in power series in m/r, with m being half the Schwarzschild radius of the central body and r a radial coordinate. The procedure exclusively works for a light ray which may be described as a perturbation in powers of G of a Minkowskian null geodesic, with G being the Newtonian gravitational constant. It is shown that the expansion of the travel time of a photon along such a ray only involves elementary integrals whatever the order of approximation. An expansion of the impact parameter in power series of G is also obtained. The method is applied to explicitly calculate the perturbation expansions of the light travel time and the impact parameter up to the third order. The full expression yielding the terms of order G 3 is new. This expression confirms the existence of a third-order enhanced term when the emitter and the receiver are in conjunction relative to the central body. This term is shown to be necessary for determining the post-Newtonian parameter γ at a level of accuracy of 10 −8 with light rays grazing the Sun. (paper)
Tunable system for production of mirror and cusp configurations using chassis of permanent magnets

Science.gov (United States)

Hyde, Alexander; Bushmelov, Maxim; Batishchev, Oleg

2018-03-01

Compact arrays of permanent magnets have shown promise as replacements for electromagnets in applications requiring magnetic cusps and mirrors. An adjustable system capable of suspending and translating a pair of light, nonmagnetic chassis carrying such sources of magnetic field has been designed and constructed. Using this device to align two cylindrical chassis, strong solenoid-like domains of field, as well as classic biconic cusp and magnetic mirror topologies, are generated. Employing a pair of ring-shaped chassis instead, the superposition of their naturally-emitted cusps is demonstrated to produce sextupolar and octupolar magnetic fields.
Partially coherent isodiffracting pulsed beams

Science.gov (United States)

Koivurova, Matias; Ding, Chaoliang; Turunen, Jari; Pan, Liuzhan

2018-02-01

We investigate a class of isodiffracting pulsed beams, which are superpositions of transverse modes supported by spherical-mirror laser resonators. By employing modal weights that, for stationary light, produce a Gaussian Schell-model beam, we extend this standard model to pulsed beams. We first construct the two-frequency cross-spectral density function that characterizes the spatial coherence in the space-frequency domain. By assuming a power-exponential spectral profile, we then employ the generalized Wiener-Khintchine theorem for nonstationary light to derive the two-time mutual coherence function that describes the space-time coherence of the ensuing beams. The isodiffracting nature of the laser resonator modes permits all (paraxial-domain) calculations at any propagation distance to be performed analytically. Significant spatiotemporal coupling is revealed in subcycle, single-cycle, and few-cycle domains, where the partial spatial coherence also leads to reduced temporal coherence even though full spectral coherence is assumed.
The obsidian mirror The obsidian mirror

Directory of Open Access Journals (Sweden)

Maria do Socorro Reis Amorin

2008-04-01

Full Text Available The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian. The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian.
Gauge/gravity duality for interactions of spherical membranes in 11-dimensional pp-wave

International Nuclear Information System (INIS)

Lee, Hok Kong; McLoughlin, Tristan; Wu Xinkai

2005-01-01

We investigate the gauge/gravity duality in the interaction between two spherical membranes in the 11-dimensional pp-wave background. On the supergravity side, we find the solution to the field equations at locations close to a spherical source membrane, and use it to obtain the light-cone Lagrangian of a spherical probe membrane very close to the source, i.e., with their separation much smaller than their radii. On the gauge theory side, using the BMN matrix model, we compute the one-loop effective potential between two membrane fuzzy spheres. Perfect agreement is found between the two sides. Moreover, the one-loop effective potential we obtain on the gauge theory side is valid beyond the small-separation approximation, giving the full interpolation between interactions of membrane-like objects and that of graviton-like objects
Nano-metrology: The art of measuring X-ray mirrors with slope errors <100 nrad.

Science.gov (United States)

Alcock, Simon G; Nistea, Ioana; Sawhney, Kawal

2016-05-01

We present a comprehensive investigation of the systematic and random errors of the nano-metrology instruments used to characterize synchrotron X-ray optics at Diamond Light Source. With experimental skill and careful analysis, we show that these instruments used in combination are capable of measuring state-of-the-art X-ray mirrors. Examples are provided of how Diamond metrology data have helped to achieve slope errors of <100 nrad for optical systems installed on synchrotron beamlines, including: iterative correction of substrates using ion beam figuring and optimal clamping of monochromator grating blanks in their holders. Simulations demonstrate how random noise from the Diamond-NOM's autocollimator adds into the overall measured value of the mirror's slope error, and thus predict how many averaged scans are required to accurately characterize different grades of mirror.
Evolution of the spherical clusters

International Nuclear Information System (INIS)

Surdin, V.G.

1978-01-01

The possible processes of the Galaxy spherical clusters formation and evolution are described on a popular level. The orbits of spherical cluster motion and their spatial velocities are determined. Given are the distrbutions of spherical cluster stars according to their velocities and the observed distribution of spherical clusters in the area of the Galaxy slow evolution. The dissipation and dynamic friction processes destructing clusters with the mass less than 10 4 of solar mass and bringing about the reduction of clusters in the Galaxy are considered. The paradox of forming mainly X-ray sources in spherical clusters is explained. The schematic image of possible ways of forming X-ray sources in spherical clusters is given
A new approach to spherically symmetric junction surfaces and the matching of FLRW regions

International Nuclear Information System (INIS)

Kirchner, U

2004-01-01

We investigate timelike junctions (with surface layer) between spherically symmetric solutions of the Einstein-field equation. In contrast to previous investigations, this is done in a coordinate system in which the junction surface motion is absorbed in the metric, while all coordinates are continuous at the junction surface. The evolution equations for all relevant quantities are derived. We discuss the no-surface layer case (boundary surface) and study the behaviour for small surface energies. It is shown that one should expect cases in which the speed of light is reached within a finite proper time. We carefully discuss necessary and sufficient conditions for a possible matching of spherically symmetric sections. For timelike junctions between spherically symmetric spacetime sections we show explicitly that the time component of the Lanczos equation always reduces to an identity (independent of the surface equation of state). The results are applied to the matching of Friedmann-LemaItre-Robertson-Walker (FLRW) models. We discuss 'vacuum bubbles' and closed-open junctions in detail. As illustrations several numerical integration results are presented, some of them indicate that (observers comoving with) the junction surface can reach the speed of light within a finite time
Laser working device

International Nuclear Information System (INIS)

Shibanuma, Kiyoshi; Kakudate, Satoshi; Oka, Kiyoshi; Terakado, Takuya; Kondo, Mitsunori; Munakata, Tadashi; Makino, Yoshinobu; Honda, Keizo.

1995-01-01

A transmission pipe transmits laser beams along an axis thereof, and is inserted at the top end to a pipeline to be fabricated. A flat mirror is secured to the top end of the transmission pipe, and laser beams are reflected by the mirror, passed through a fabrication nozzle and focused to a fabrication point in the pipeline to be fabricated. A lens-type light focusing system is guided to the fabrication point by a plurality of rollers rotatable in the axial direction disposed in circumferential direction each at an equal pitch at the outer circumference of the transmission pipe. A centering mechanism is disposed for keeping the transmission pipe coaxially with the pipeline to be fabricated. Further, there are also disposed a mirror-type light focusing optical system for focusing light by a paraboloidal mirror and a spherical vehicle rotatable in all directions. A laser fabrication device can be reduced in the size, and it can be used in a high temperature and highly radioactive circumstance. (N.H.)
Tandem mirror plasma confinement apparatus

Science.gov (United States)

Fowler, T. Kenneth

1978-11-14

Apparatus and method for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell.
Magneto-hydrodynamically stable axisymmetric mirrors

Energy Technology Data Exchange (ETDEWEB)

Ryutov, D. D.; Cohen, B. I.; Molvik, A. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Berk, H. L. [University of Texas, Austin, Texas 78712 (United States); Simonen, T. C. [University of California, Berkeley, California 94720 (United States)

2011-09-15

Making axisymmetric mirrors magnetohydrodynamically (MHD) stable opens up exciting opportunities for using mirror devices as neutron sources, fusion-fission hybrids, and pure-fusion reactors. This is also of interest from a general physics standpoint (as it seemingly contradicts well-established criteria of curvature-driven instabilities). The axial symmetry allows for much simpler and more reliable designs of mirror-based fusion facilities than the well-known quadrupole mirror configurations. In this tutorial, after a summary of classical results, several techniques for achieving MHD stabilization of the axisymmetric mirrors are considered, in particular: (1) employing the favorable field-line curvature in the end tanks; (2) using the line-tying effect; (3) controlling the radial potential distribution; (4) imposing a divertor configuration on the solenoidal magnetic field; and (5) affecting the plasma dynamics by the ponderomotive force. Some illuminative theoretical approaches for understanding axisymmetric mirror stability are described. The applicability of the various stabilization techniques to axisymmetric mirrors as neutron sources, hybrids, and pure-fusion reactors are discussed; and the constraints on the plasma parameters are formulated.
Survey of mirror machine reactors

International Nuclear Information System (INIS)

Condit, W.C.

1978-01-01

The Magnetic Mirror Fusion Program is one of the two main-line fusion efforts in the United States. Starting from the simple axisymmetric mirror concept in the 1950's, the program has successfully overcome gross flute-type instabilities (using minimum-B magnetic fields), and the most serious of the micro-instabilities which plagued it (the drift-cyclotron loss-cone mode). Dense plasmas approaching the temperature range of interest for fusion have been created (n/sub p/ = 10 14 /cc at 10 to 12 keV). At the same time, rather extensive conceptual design studies of possible mirror configurations have led to three principle designs of interest: the standard mirror fission-fusion hybrid, tandem mirror, and the field-reversed mirror. The lectures will discuss these three concepts in turn. There will be no discussion of diagnostics for the mirror machine in these lectures, but typical plasma parameters will be given for each type of machine, and the diagnostic requirements will be apparent. In a working fusion reactor, diagnostics will be required for operational control, and remarks will be made on this subject
Fundamentals of spherical array processing

CERN Document Server

Rafaely, Boaz

2015-01-01

This book provides a comprehensive introduction to the theory and practice of spherical microphone arrays. It is written for graduate students, researchers and engineers who work with spherical microphone arrays in a wide range of applications. The first two chapters provide the reader with the necessary mathematical and physical background, including an introduction to the spherical Fourier transform and the formulation of plane-wave sound fields in the spherical harmonic domain. The third chapter covers the theory of spatial sampling, employed when selecting the positions of microphones to sample sound pressure functions in space. Subsequent chapters present various spherical array configurations, including the popular rigid-sphere-based configuration. Beamforming (spatial filtering) in the spherical harmonics domain, including axis-symmetric beamforming, and the performance measures of directivity index and white noise gain are introduced, and a range of optimal beamformers for spherical arrays, includi...
Tandem mirror plasma confinement apparatus

International Nuclear Information System (INIS)

Fowler, T.K.

1978-01-01

Apparatus and method are described for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell
The mirror-neuron system.

Science.gov (United States)

Rizzolatti, Giacomo; Craighero, Laila

2004-01-01

A category of stimuli of great importance for primates, humans in particular, is that formed by actions done by other individuals. If we want to survive, we must understand the actions of others. Furthermore, without action understanding, social organization is impossible. In the case of humans, there is another faculty that depends on the observation of others' actions: imitation learning. Unlike most species, we are able to learn by imitation, and this faculty is at the basis of human culture. In this review we present data on a neurophysiological mechanism--the mirror-neuron mechanism--that appears to play a fundamental role in both action understanding and imitation. We describe first the functional properties of mirror neurons in monkeys. We review next the characteristics of the mirror-neuron system in humans. We stress, in particular, those properties specific to the human mirror-neuron system that might explain the human capacity to learn by imitation. We conclude by discussing the relationship between the mirror-neuron system and language.
Physics of mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1982-05-01

In recent years the emphasis in research on the magnetic mirror approach to fusion has been shifted to address what are essentially economically-motivated issues. The introduction of the Tandem Mirror idea solved in principal the problem of low Q (low fusion power gain) of mirror-based fusion systems. In order to optimize the tandem mirror idea from an economic standpoint, some important improvements have been suggested. These improvements include the thermal barrier idea of Baldwin and Logan and the axicell concept of Kesner. These new modifications introduce some special physics considerations. Among these are (1) The MHD stability properties of high energy electron components in the end cells; (2) The optimization of end-cell magnetic field configurations with the objective of minimizing equilibrium parallel currents; (3) The suppression of microstabilities by use of sloshing ion distributions. Following a brief outline of tandem mirror concepts, the above three topics are discussed, with illustrative examples taken from earlier work or from recent design studies
Light

CERN Document Server

Robertson, William C

2003-01-01

Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...
650-nm-band high-power and highly reliable laser diodes with a window-mirror structure

Science.gov (United States)

Shima, Akihiro; Hironaka, Misao; Ono, Ken-ichi; Takemi, Masayoshi; Sakamoto, Yoshifumi; Kunitsugu, Yasuhiro; Yamashita, Koji

1998-05-01

An active layer structure with 658 nm-emission at 25 degrees Celsius has been optimized in order to reduce the operating current of the laser diodes (LD) under high temperature condition. For improvement of the maximum output power and the reliability limited by mirror degradation, we have applied a zinc-diffused-type window-mirror structure which prevents the optical absorption at the mirror facet. As a result, the CW output power of 50 mW is obtained even at 80 degrees Celsius for a 650 micrometer-long window-mirror LD. In addition, the maximum light output power over 150 mW at 25 degrees Celsius has been realized without any optical mirror damage. In the aging tests, the LDs have been operating for over 2,500 - 5,000 hours under the CW condition of 30 - 50 mW at 60 degrees Celsius. The window-mirror structure also enables reliable 60 degree Celsius, 30 mW, CW operation of the LDs with 651 nm- emission at 25 degrees Celsius. Moreover, the maximum output power of around 100 mW even at 80 degrees Celsius and reliable 2,000-hour operation at 60 degrees Celsius, 70 mW have been realized for the first time by 659 nm LDs with a long cavity length of 900 micrometers.
Galileon radiation from a spherical collapsing shell

Energy Technology Data Exchange (ETDEWEB)

Martín-García, Javier [Instituto de Física Teórica UAM/CSIC,C/ Nicolás Cabrera 15, E-28049 Madrid (Spain); Vázquez-Mozo, Miguel Á. [Instituto Universitario de Física Fundamental y Matemáticas (IUFFyM),Universidad de Salamanca, Plaza de la Merced s/n, E-37008 Salamanca (Spain)

2017-01-17

Galileon radiation in the collapse of a thin spherical shell of matter is analyzed. In the framework of a cubic Galileon theory, we compute the field profile produced at large distances by a short collapse, finding that the radiated field has two peaks traveling ahead of light fronts. The total energy radiated during the collapse follows a power law scaling with the shell’s physical width and results from two competing effects: a Vainshtein suppression of the emission and an enhancement due to the thinness of the shell.
Structure in defocused beams of x-ray mirrors: causes and possible solutions

Science.gov (United States)

Sutter, John P.; Alcock, Simon G.; Rust, Fiona; Wang, Hongchang; Sawhney, Kawal

2014-09-01

Grazing incidence mirrors are now a standard optic for focusing X-ray beams. Both bimorph and mechanically bendable mirrors are widely used at Diamond Light Source because they permit a wide choice of focal lengths. They can also be deliberately set out of focus to enlarge the X-ray beam, and indeed many beamline teams now wish to generate uniform beam spots of variable size. However, progress has been slowed by the appearance of fine structure in these defocused beams. Measurements showing the relationship between the medium-frequency polishing error and this structure over a variety of beam sizes will be presented. A theoretical model for the simulations of defocused beams from general mirrors will then be developed. Not only the figure error and its first derivative the slope error, but also the second derivative, the curvature error, must be considered. In conclusion, possible ways to reduce the defocused beam structure by varying the actuators' configuration and settings will be discussed.

Mirror monochromator

Energy Technology Data Exchange (ETDEWEB)

Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States); Shadman, Khashayar [Electron Optica, Inc., Palo Alto, CA (United States)

2014-12-02

In this SBIR project, Electron Optica, Inc. (EOI) is developing a mirror electron monochromator (MirrorChrom) attachment to new and retrofitted electron microscopes (EMs) for improving the energy resolution of the EM from the characteristic range of 0.2-0.5 eV to the range of 10-50 meV. This improvement will enhance the characterization of materials by imaging and spectroscopy. In particular, the monochromator will refine the energy spectra characterizing materials, as obtained from transmission EMs [TEMs] fitted with electron spectrometers, and it will increase the spatial resolution of the images of materials taken with scanning EMs (SEMs) operated at low voltages. EOI’s MirrorChrom technology utilizes a magnetic prism to simultaneously deflect the electron beam off the axis of the microscope column by 90° and disperse the electrons in proportional to their energies into a module with an electron mirror and a knife-edge. The knife-edge cuts off the tails of the energy distribution to reduce the energy spread of the electrons that are reflected, and subsequently deflected, back into the microscope column. The knife-edge is less prone to contamination, and thereby charging, than the conventional slits used in existing monochromators, which improves the reliability and stability of the module. The overall design of the MirrorChrom exploits the symmetry inherent in reversing the electron trajectory in order to maintain the beam brightness – a parameter that impacts how well the electron beam can be focused downstream onto a sample. During phase I, EOI drafted a set of candidate monochromator architectures and evaluated the trade-offs between energy resolution and beam current to achieve the optimum design for three particular applications with market potential: increasing the spatial resolution of low voltage SEMs, increasing the energy resolution of low voltage TEMs (beam energy of 5-20 keV), and increasing the energy resolution of conventional TEMs (beam
Physics of mirror fusion systems

International Nuclear Information System (INIS)

Post, R.F.

1976-01-01

Recent experimental results with the 2XIIB mirror machine at Lawrence Livermore Laboratory have demonstrated the stable confinement of plasmas at fusion temperatures and with energy densities equaling or exceeding that of the confining fields. The physics of mirror confinement is discussed in the context of these new results. Some possible approaches to further improving the confinement properties of mirror systems and the impact of these new approaches on the prospects for mirror fusion reactors are discussed
Thermal effects on beryllium mirrors

International Nuclear Information System (INIS)

Weinswig, S.

1989-01-01

Beryllium is probably the most frequently used material for spaceborne system scan mirrors. Beryllium's properties include lightweightedness, high Young's modulus, high stiffness value, high resonance value. As an optical surface, beryllium is usually nickel plated in order to produce a higher quality surface. This process leads to the beryllium mirror acting like a bimetallic device. The mirror's deformation due to the bimetallic property can possibly degrade the performance of the associated optical system. As large space borne systems are designed and as temperature considerations become more crucial in the instruments, the concern about temporal deformation of the scan mirrors becomes a prime consideration. Therefore, two sets of tests have been conducted in order to ascertain the thermal effects on nickel plated beryllium mirrors. These tests are categorized. The purpose of this paper is to present the values of the bimetallic effect on typical nickel plated beryllium mirrors
Linearized vector radiative transfer model MCC++ for a spherical atmosphere

International Nuclear Information System (INIS)

Postylyakov, O.V.

2004-01-01

Application of radiative transfer models has shown that optical remote sensing requires extra characteristics of radiance field in addition to the radiance intensity itself. Simulation of spectral measurements, analysis of retrieval errors and development of retrieval algorithms are in need of derivatives of radiance with respect to atmospheric constituents under investigation. The presented vector spherical radiative transfer model MCC++ was linearized, which allows the calculation of derivatives of all elements of the Stokes vector with respect to the volume absorption coefficient simultaneously with radiance calculation. The model MCC++ employs Monte Carlo algorithm for radiative transfer simulation and takes into account aerosol and molecular scattering, gas and aerosol absorption, and Lambertian surface albedo. The model treats a spherically symmetrical atmosphere. Relation of the estimated derivatives with other forms of radiance derivatives: the weighting functions used in gas retrieval and the air mass factors used in the DOAS retrieval algorithms, is obtained. Validation of the model against other radiative models is overviewed. The computing time of the intensity for the MCC++ model is about that for radiative models treating sphericity of the atmosphere approximately and is significantly shorter than that for the full spherical models used in the comparisons. The simultaneous calculation of all derivatives (i.e. with respect to absorption in all model atmosphere layers) and the intensity is only 1.2-2 times longer than the calculation of the intensity only
Potential measurements in tandem mirrors

International Nuclear Information System (INIS)

Glowienka, J.C.

1985-11-01

The US mirror program has begun conducting experiments with a thermal barrier tandem mirror configuration. This configuration requires a specific axial potential profile and implies measurements of potential for documentation and optimization of the configuration. This report briefly outlines the motivation for the thermal barrier tandem mirror and then outlines the techniques used to document the potential profile in conventional and thermal barrier tandem mirrors. Examples of typical data sets from the world's major tandem mirror experiments, TMX and TMX-U at Lawrence Livermore National Laboratory (LLNL) and Gamma 10 at Tsukuba University in Japan, and the current interpretation of the data are discussed together with plans for the future improvement of measurements of plasma potential
TCV mirrors cleaned by plasma

Directory of Open Access Journals (Sweden)

L. Marot

2017-08-01

Full Text Available Metallic mirrors exposed in TCV tokamak were cleaned by plasma in laboratory. A gold (Au mirror was deposited with 185–285nm of amorphous carbon (aC:D film coming from the carbon tiles of TCV. Another molybdenum (Mo mirror had a thicker deposit due to a different location within the tokamak. The thickness measurements were carried out using ellipsometry and the reflectivity measurements performed by spectrophotometry revealed a decrease of the specular reflectivity in the entire range (250–2500nm for the Mo mirror and specifically in the visible spectrum for the Au. Comparison of the simulated reflectivity using a refractive index of 1.5 and a Cauchy model for the aC:D gives good confidence on the estimated film thickness. Plasma cleaning using radio frequency directly applied to a metallic plate where the mirrors were fixed demonstrated the ability to remove the carbon deposits. A mixture of 50% hydrogen and 50% helium was used with a −200V self-bias. Due to the low sputtering yield of He and the low chemical erosion of hydrogen leading to volatile molecules, 20h of cleaning were needed for Au mirror and more than 60h for Mo mirror. Recovery of the reflectivity was not complete for the Au mirror most likely due to damage of the surface during tokamak exposure (breakdown phenomena.
Spherical CNNs

OpenAIRE

Cohen, Taco S.; Geiger, Mario; Koehler, Jonas; Welling, Max

2018-01-01

Convolutional Neural Networks (CNNs) have become the method of choice for learning problems involving 2D planar images. However, a number of problems of recent interest have created a demand for models that can analyze spherical images. Examples include omnidirectional vision for drones, robots, and autonomous cars, molecular regression problems, and global weather and climate modelling. A naive application of convolutional networks to a planar projection of the spherical signal is destined t...
Design and investigation of photo-induced super-hydrophilic materials for car mirrors

International Nuclear Information System (INIS)

Eiamchai, Pitak; Chindaudom, Pongpan; Horprathum, Mati; Patthanasettakul, Viyapol; Limsuwan, Pichet

2009-01-01

During the past decades, interests in various properties in titanium dioxide thin films have been growing rapidly. There have been several reports for TiO 2 thin films prepared on various media with photocatalytic and hydrophilic properties, in order to function as self-cleaning and/or anti-fogging materials. An obvious application is usually found in side-view car mirrors in the automobile industries. In this study, a number of photocatalytic TiO 2 films are prepared on soda-lime glasses for car mirrors by an electron-beam evaporation. The designs and development of the photocatalytic TiO 2 films, based on crystallinity, deposition rate, film thickness, film structure, and surface roughness are discussed. In comparison to the commercialized products, a systematic investigation procedure for the super-hydrophilic properties of the light-induced TiO 2 films for car mirrors has been developed, based on super-hydrophilicity, sustainability, self-cleaning property, and degradation of the samples. In addition, physical characterization by X-ray diffraction and surface roughness are also discussed. It has been found that most commercial products attain super-hydrophilicity only after exposed to ultraviolet and solar irradiation in less than 1 h. They can also maintain hydrophilicity after rigorous cleaning process. On the other hand, our prepared TiO 2 thin films demonstrate super-hydrophilic and photocatalytic properties after exposed to ultraviolet light for more than 2 h. According to the study, their anatase crystallinity, small grain size, and surface conditions all contributes to the excellent results. However, the prepared samples do not attain sufficient retention property to maintain their hydrophilicity. Conclusively, the designs of the TiO 2 films on car mirrors prove adequate to produce super-hydrophilic materials, which still degrade over normal usage. Nevertheless, our proposed investigation methods prove useful in quality evaluation in order to
Centimeter-scale MEMS scanning mirrors for high power laser application

Science.gov (United States)

Senger, F.; Hofmann, U.; v. Wantoch, T.; Mallas, C.; Janes, J.; Benecke, W.; Herwig, Patrick; Gawlitza, P.; Ortega-Delgado, M.; Grune, C.; Hannweber, J.; Wetzig, A.

2015-02-01

A higher achievable scan speed and the capability to integrate two scan axes in a very compact device are fundamental advantages of MEMS scanning mirrors over conventional galvanometric scanners. There is a growing demand for biaxial high speed scanning systems complementing the rapid progress of high power lasers for enabling the development of new high throughput manufacturing processes. This paper presents concept, design, fabrication and test of biaxial large aperture MEMS scanning mirrors (LAMM) with aperture sizes up to 20 mm for use in high-power laser applications. To keep static and dynamic deformation of the mirror acceptably low all MEMS mirrors exhibit full substrate thickness of 725 μm. The LAMM-scanners are being vacuum packaged on wafer-level based on a stack of 4 wafers. Scanners with aperture sizes up to 12 mm are designed as a 4-DOF-oscillator with amplitude magnification applying electrostatic actuation for driving a motor-frame. As an example a 7-mm-scanner is presented that achieves an optical scan angle of 32 degrees at 3.2 kHz. LAMM-scanners with apertures sizes of 20 mm are designed as passive high-Q-resonators to be externally excited by low-cost electromagnetic or piezoelectric drives. Multi-layer dielectric coatings with a reflectivity higher than 99.9 % have enabled to apply cw-laser power loads of more than 600 W without damaging the MEMS mirror. Finally, a new excitation concept for resonant scanners is presented providing advantageous shaping of intensity profiles of projected laser patterns without modulating the laser. This is of interest in lighting applications such as automotive laser headlights.
Design of the deformable mirror demonstration CubeSat (DeMi)

Science.gov (United States)

Douglas, Ewan S.; Allan, Gregory; Barnes, Derek; Figura, Joseph S.; Haughwout, Christian A.; Gubner, Jennifer N.; Knoedler, Alex A.; LeClair, Sarah; Murphy, Thomas J.; Skouloudis, Nikolaos; Merck, John; Opperman, Roedolph A.; Cahoy, Kerri L.

2017-09-01

The Deformable Mirror Demonstration Mission (DeMi) was recently selected by DARPA to demonstrate in-space operation of a wavefront sensor and Microelectromechanical system (MEMS) deformable mirror (DM) payload on a 6U CubeSat. Space telescopes designed to make high-contrast observations using internal coronagraphs for direct characterization of exoplanets require the use of high-actuator density deformable mirrors. These DMs can correct image plane aberrations and speckles caused by imperfections, thermal distortions, and diffraction in the telescope and optics that would otherwise corrupt the wavefront and allow leaking starlight to contaminate coronagraphic images. DeMi is provide on-orbit demonstration and performance characterization of a MEMS deformable mirror and closed loop wavefront sensing. The DeMi payload has two operational modes, one mode that images an internal light source and another mode which uses an external aperture to images stars. Both the internal and external modes include image plane and pupil plane wavefront sensing. The objectives of the internal measurement of the 140-actuator MEMS DM actuator displacement are characterization of the mirror performance and demonstration of closed-loop correction of aberrations in the optical path. Using the external aperture to observe stars of magnitude 2 or brighter, assuming 3-axis stability with less than 0.1 degree of attitude knowledge and jitter below 10 arcsec RMSE, per observation, DeMi will also demonstrate closed loop wavefront control on an astrophysical target. We present an updated payload design, results from simulations and laboratory optical prototyping, as well as present our design for accommodating high-voltage multichannel drive electronics for the DM on a CubeSat.
A light/dark cycle in the NICU accelerates body weight gain and shortens time to discharge in preterm infants.

Science.gov (United States)

Vásquez-Ruiz, Samuel; Maya-Barrios, José Alfonso; Torres-Narváez, Patricia; Vega-Martínez, Benito Rubén; Rojas-Granados, Adelina; Escobar, Carolina; Angeles-Castellanos, Manuel

2014-09-01

Bright constant light levels in the NICU may have negative effects on the growth and development of preterm infants The aim of this study is to evaluate the benefits of an alternating light/dark cycle in the NICU on weight gain and early discharge from the therapy in premature infants. A randomized interventional study was designed comparing infants in the NICU of Hospital Juarez de México, exposed from birth either to an LD environment (LD, n=19) or to the traditional continuous light (LL, n=19). The LD condition was achieved by placing individual removable helmets over the infant's heads. Body weight gain was analyzed, as the main indicator of stability and the main criteria for discharge in preterm infants born at 31.73±0.31week gestational age. Infants maintained in an LD cycle gained weight faster than infants in LL and therefore attained a shorter hospital stay, (34.37±3.12 vs 51.11±5.29days; P>0.01). Also, LD infants exhibited improved oxygen saturation and developed a daily melatonin rhythm. These findings provide a convenient alternative for establishing an LD environment for preterm healthy newborns in the NICU and confirm the beneficial effects of an alternating LD cycle for growth and weight gain and for earlier discharge time. Here we provide an easy and practical alternative to implement light/dark conditions in the NICU. Copyright © 2014 Elsevier Ltd. All rights reserved.
High-throughput fabrication of micrometer-sized compound parabolic mirror arrays by using parallel laser direct-write processing

International Nuclear Information System (INIS)

Yan, Wensheng; Gu, Min; Cumming, Benjamin P

2015-01-01

Micrometer-sized parabolic mirror arrays have significant applications in both light emitting diodes and solar cells. However, low fabrication throughput has been identified as major obstacle for the mirror arrays towards large-scale applications due to the serial nature of the conventional method. Here, the mirror arrays are fabricated by using a parallel laser direct-write processing, which addresses this barrier. In addition, it is demonstrated that the parallel writing is able to fabricate complex arrays besides simple arrays and thus offers wider applications. Optical measurements show that each single mirror confines the full-width at half-maximum value to as small as 17.8 μm at the height of 150 μm whilst providing a transmittance of up to 68.3% at a wavelength of 633 nm in good agreement with the calculation values. (paper)
Fokker-Planck equation in mirror research

International Nuclear Information System (INIS)

Post, R.F.

1983-01-01

Open confinement systems based on the magnetic mirror principle depend on the maintenance of particle distributions that may deviate substantially from Maxwellian distributions. Mirror research has therefore from the beginning relied on theoretical predictions of non-equilibrium rate processes obtained from solutions to the Fokker-Planck equation. The F-P equation plays three roles: Design of experiments, creation of classical standards against which to compare experiment, and predictions concerning mirror based fusion power systems. Analytical and computational approaches to solving the F-P equation for mirror systems will be reviewed, together with results and examples that apply to specific mirror systems, such as the tandem mirror
The application of angular resolved scatter to the documentation of damage to smooth mirrors

International Nuclear Information System (INIS)

Gillespie, C.H.; Edwards, D.F.; Stover, J.C.

1986-01-01

Mirrors designed to survive exposure to damaging radiation are being irradiated and then measured to determine the mechanisms of failure and to improve the ability of analysis codes to predict an exposure damage threshold. The differences between survival and catastrophic failure are easily recognized and recorded by macro photography. However, the coal of this project is to quantify the onset of mirror degradation utilizing non contact methods that have good measurement sensitivity to small changes in reflectivity (material properties) and light scatter (roughness). A new angular resolved scatterometer is described that has an extended dynamic range and integrated analysis capable of displaying the surface power spectral density (PSD) over large bandwidths of surface spatial frequencies. Graphical displays of the scattered light power before and after exposure to the radiation are compared and integrated over equivalent spatial bandwidths of sensitivity for other instruments to compare calculated RMS roughness values
Initial results from the TST-2 spherical tokamak

International Nuclear Information System (INIS)

Takase, Y.; Ejiri, A.; Kasuya, N.

2001-01-01

A new spherical tokamak TST-2 was constructed at the University of Tokyo and started operation in September 1999. Reliable plasma initiation is achieved with typically 1 kW of ECH power at 2.45 GHz. Plasma currents of up to 90 kA and toroidal fields of up to 0.2 T have been achieved during the initial experimental campaign. The ion temperature is typically 100 eV. Internal reconnection events (IREs) are often observed. The internal magnetic field measured at r/a=2/3 indicated growth of fluctuations up to the 4 th harmonic, suggesting the existence of modes with several different mode numbers. In the presence of a toroidal field and a vertically oriented mirror field, noninductively driven currents of order 1 kA were observed with 1 kW of ECH power. The driven current increased with decreasing filling pressure, down to 3x10 -6 torr. A study of high harmonic fast wave (HHFW) excitation and propagation has begun. Initial results indicate highly efficient wave launching. (author)
Gamma Bang Time/Reaction History Diagnostics for the National Ignition Facility (NIF) Using 900 Off-axis Parabolic Mirrors

International Nuclear Information System (INIS)

H.W. Herrmann; R.M. Malone; W. Stoeffl; J.M. Mack; C.S. Young

2008-01-01

Gas Cherenkov detectors (GCD) have been used to convert fusion gamma into photons to achieve gamma bang time (GBT) and reaction history measurements. The GCD designed for Omega used Cassegrain reflector optics in order to fit inside a ten-inch manipulator. A novel design for the National Ignition Facility (NIF) using 90 o Off-Axis Parabolic (OAP) mirrors will increase light collection efficiency from fusion gammas and achieve minimum time dispersion. The broadband Cherenkov light (from 200 to 800 nm) is relayed into a high-speed detector using three parabolic mirrors. Because light is collected from many source planes throughout the CO2 gas volume, the detector is positioned at the stop position rather than an image position. The stop diameter and its position are independent of the light-generation location along the gas cell. The current design collects light from a 100-mm diameter by 500-mm-long gas volume. Optical ray tracings demonstrate how light can be collected from different angled trajectories of the Compton electrons as they fly through the CO2 gas volume. A cluster of four channels will allow for increased dynamic range as well as different gamma energy threshold sensitivities
Gamma bang time/reaction history diagnostics for the National Ignition Facility using 90 degrees off-axis parabolic mirrors.

Science.gov (United States)

Malone, R M; Herrmann, H W; Stoeffl, W; Mack, J M; Young, C S

2008-10-01

Gas Cherenkov detectors (GCDs) have been used to convert fusion gamma into photons to achieve gamma bang time and reaction history measurements. The GCDs designed for OMEGA used Cassegrain reflector optics in order to fit inside a 10 in. manipulator. A novel design for the National Ignition Facility using 90 degrees off-axis parabolic mirrors will increase light collection efficiency from fusion gammas and achieve minimum time dispersion. The broadband Cherenkov light (from 200 to 800 nm) is relayed into a high-speed detector using three parabolic mirrors. Because light is collected from many source planes throughout the CO(2) gas volume, the detector is positioned at the stop position rather than at an image position. The stop diameter and its position are independent of the light-generation location along the gas cell. The current design collects light from a 100 mm diameter by 500 mm long gas volume. Optical ray tracings demonstrate how light can be collected from different angled trajectories of the Compton electrons as they fly through the CO(2) gas volume. A cluster of four channels will allow for increased dynamic range as well as for different gamma energy threshold sensitivities.
Dispersion measurement on chirped mirrors at arbitrary incidence angle and polarization state (Conference Presentation)

Science.gov (United States)

Kovacs, Mate; Somoskoi, Tamas; Seres, Imre; Borzsonyi, Adam; Sipos, Aron; Osvay, Károly

2017-05-01

The optical elements of femtosecond high peak power lasers have to fulfill more and more strict requirements in order to support pulses with high intensity and broad spectrum. In most cases chirped pulse amplification scheme is used to generate high peak power ultrashort laser pulses, where a very precise control of spectral intensity and spectral phase is required in reaching transform-limited temporal shape at the output. In the case of few cycle regime, the conventional bulk glass, prism-, grating- and their combination based compressors are not sufficient anymore, due to undesirable nonlinear effects in their material and proneness to optical damages. The chirped mirrors are also commonly used to complete the compression after a beam transport system just before the target. Moreover, the manufacturing technology requires quality checks right after production and over the lifetime of the mirror as well, since undesired deposition on the surface can lead alteration from the designed value over a large part of the aperture. For the high harmonic generation, polarization gating technology is used to generate single attosecond pulses [1]. In this case the pulse to be compressed has various polarization state falling to the chirped mirrors. For this reason, it is crucial to measure the dispersion of the mirrors for the different polarization states. In this presentation we demonstrate a simple technique to measure the dispersion of arbitrary mirror at angles of incidence from 0 to 55 degree, even for a 12" optics. A large aperture 4" mirror has been scanned over with micrometer accuracy and the dispersion property through the surface has been investigated with a stable interference fringes in that robust geometry. We used Spectrally Resolved Interferometry, which is based on a Michaelson interferometer and a combined visible and infrared spectrometer. Tungsten halogen lamp with 10 mW coupled optical power was used as a white-light source so with the selected
Figure and finish characterization of high performance metal mirrors

International Nuclear Information System (INIS)

Takacs, P.Z.; Church, E.L.

1991-10-01

Most metal mirrors currently used in synchrotron radiation (SR) beam lines to reflect soft x-rays are made of electroless nickel plate on an aluminum substrate. This material combination has allowed optical designers to incorporate exotic cylindrical aspheres into grazing incidence x-ray beam-handling systems by taking advantage of single-point diamond machining techniques. But the promise of high-quality electroless nickel surfaces has generally exceeded the performance. We will examine the evolution of electroless nickel surfaces through a study of the quality of mirrors delivered for use at the National Synchrotron Light Source over the past seven years. We have developed techniques to assess surface quality based on the measurement of surface roughness and figure errors with optical profiling instruments. It is instructive to see how the quality of the surface is related to the complexity of the machine operations required to produce it
Effects of mirror symmetry on the transmission fingerprints of quasiperiodic photonic multilayers

International Nuclear Information System (INIS)

Coelho, I.P.; Vasconcelos, M.S.; Bezerra, C.G.

2010-01-01

We address the transmission properties of light waves through symmetric Fibonacci, Thue-Morse and double-period photonic multilayers, i.e., a binary one-dimensional quasiperiodic structure made up of two different dielectric materials (more specifically SiO 2 and TiO 2 ), in quarter wavelength condition, presenting mirror symmetry. The optical spectra are calculated by using a theoretical model based on the transfer matrix approach in normal incidence geometry. In our results we present the self-similar features of the spectra and we also present the optical fingerprints through a return map of the transmission coefficients. We discuss these optical fingerprints and compare them with results of previous works, on similar quasiperiodic systems, in the absence of mirror symmetry.

Light-weight radioisotope heater impact tests

International Nuclear Information System (INIS)

Reimus, M.A.H.; Rinehart, G.H.; Herrera, A.

1998-01-01

The light-weight radioisotope heater unit (LWRHU) is a 238 PuO 2 -fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed 238 PuO 2 fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s
Mirroring patients – or not

DEFF Research Database (Denmark)

Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

2015-01-01

on studies of imitative behaviour within linguistics and psychology, we argue that interactional mirroring is an important aspect of displaying implicit mentalization. We aimed to explore if, and in that case how, mirroring is displayed by general practitioners (GPs) and psychiatrists in consultations...... with patients with depression. We wanted to see how implicit mentalizing unfolds in physician–patient interactions. Consultations were videorecorded and analysed within the framework of conversation analysis. GPs and psychiatrists differed substantially in their propensity to mirror body movements and verbal...... and acoustic features of speech. GPs mirrored their patients more than psychiatrists in all modalities and were more flexible in their interactional behaviour. Psychiatrists seemed more static, regardless of the emotionality displayed by patients. Implicitly mirroring and attuning to patients could signify...
Spectral singularities, threshold gain, and output intensity for a slab laser with mirrors

Science.gov (United States)

Doğan, Keremcan; Mostafazadeh, Ali; Sarısaman, Mustafa

2018-05-01

We explore the consequences of the emergence of linear and nonlinear spectral singularities in TE modes of a homogeneous slab of active optical material that is placed between two mirrors. We use the results together with two basic postulates regarding the behavior of laser light emission to derive explicit expressions for the laser threshold condition and output intensity for these modes of the slab and discuss their physical implications. In particular, we reveal the details of the dependence of the threshold gain and output intensity on the position and properties of the mirrors and on the real part of the refractive index of the gain material.
Preparation and Optical Properties of Spherical Inverse Opals by Liquid Phase Deposition Using Spherical Colloidal Crystals

International Nuclear Information System (INIS)

Aoi, Y; Tominaga, T

2013-01-01

Titanium dioxide (TiO 2 ) inverse opals in spherical shape were prepared by liquid phase deposition (LPD) using spherical colloidal crystals as templates. Spherical colloidal crystals were produced by ink-jet drying technique. Aqueous emulsion droplets that contain polystyrene latex particles were ejected into air and dried. Closely packed colloidal crystals with spherical shape were obtained. The obtained spherical colloidal crystals were used as templates for the LPD. The templates were dispersed in the deposition solution of the LPD, i.e. a mixed solution of ammonium hexafluorotitanate and boric acid and reacted for 4 h at 30 °C. After the LPD process, the interstitial spaces of the spherical colloidal crystals were completely filled with titanium oxide. Subsequent heat treatment resulted in removal of templates and spherical titanium dioxide inverse opals. The spherical shape of the template was retained. SEM observations indicated that the periodic ordered voids were surrounded by titanium dioxide. The optical reflectance spectra indicated that the optical properties of the spherical titanium dioxide inverse opals were due to Bragg diffractions from the ordered structure. Filling in the voids of the inverse opals with different solvents caused remarkable changes in the reflectance peak.
A New Light Weight Structural Material for Nuclear Structures

Energy Technology Data Exchange (ETDEWEB)

Rabiei, Afsaneh [North Carolina State Univ., Raleigh, NC (United States)

2016-01-14

Radiation shielding materials are commonly used in nuclear facilities to attenuate the background ionization radiations to a minimum level for creating a safer workplace, meeting regulatory requirements and maintaining high quality performance. The conventional radiation shielding materials have a number of drawbacks: heavy concrete contains a high amount of elements that are not desirable for an effective shielding such as oxygen, silicon, and calcium; a well known limitation of lead is its low machinability and toxicity, which is causing a major environmental concern. Therefore, an effective and environmentally friendly shielding material with increased attenuation and low mass density is desirable. Close-cell composite metal foams (CMFs) and open-cell Al foam with fillers are light-weight candidate materials that we have studied in this project. Close-cell CMFs possess several suitable properties that are unattainable by conventional radiation shielding materials such as low density and high strength for structural applications, high surface area to volume ratio for excellent thermal isolation with an extraordinary energy absorption capability. Open-cell foam is made up of a network of interconnected solid struts, which allows gas or fluid media to pass through it. This unique structure provided a further motive to investigate its application as radiation shields by infiltrating original empty pores with high hydrogen or boron compounds, which are well known for their excellent neutron shielding capability. The resulting open-cell foam with fillers will not only exhibit light weight and high specific surface area, but also possess excellent radiation shielding capability and good processability. In this study, all the foams were investigated for their radiation shielding efficiency in terms of X-ray, gamma ray and neutron. X-ray transmission measurements were carried out on a high-resolution microcomputed tomography (microCT) system. Gamma-emitting sources: 3.0m
A New Light Weight Structural Material for Nuclear Structures

International Nuclear Information System (INIS)

Rabiei, Afsaneh

2016-01-01

Radiation shielding materials are commonly used in nuclear facilities to attenuate the background ionization radiations to a minimum level for creating a safer workplace, meeting regulatory requirements and maintaining high quality performance. The conventional radiation shielding materials have a number of drawbacks: heavy concrete contains a high amount of elements that are not desirable for an effective shielding such as oxygen, silicon, and calcium; a well known limitation of lead is its low machinability and toxicity, which is causing a major environmental concern. Therefore, an effective and environmentally friendly shielding material with increased attenuation and low mass density is desirable. Close-cell composite metal foams (CMFs) and open-cell Al foam with fillers are light-weight candidate materials that we have studied in this project. Close-cell CMFs possess several suitable properties that are unattainable by conventional radiation shielding materials such as low density and high strength for structural applications, high surface area to volume ratio for excellent thermal isolation with an extraordinary energy absorption capability. Open-cell foam is made up of a network of interconnected solid struts, which allows gas or fluid media to pass through it. This unique structure provided a further motive to investigate its application as radiation shields by infiltrating original empty pores with high hydrogen or boron compounds, which are well known for their excellent neutron shielding capability. The resulting open-cell foam with fillers will not only exhibit light weight and high specific surface area, but also possess excellent radiation shielding capability and good processability. In this study, all the foams were investigated for their radiation shielding efficiency in terms of X-ray, gamma ray and neutron. X-ray transmission measurements were carried out on a high-resolution microcomputed tomography (microCT) system. Gamma-emitting sources: 3.0m
Application of identifying transmission spheres for spherical surface testing

Science.gov (United States)

Han, Christopher B.; Ye, Xin; Li, Xueyuan; Wang, Quanzhao; Tang, Shouhong; Han, Sen

2017-06-01

We developed a new application on Microsoft Foundation Classes (MFC) to identify correct transmission spheres (TS) for Spherical Surface Testing (SST). Spherical surfaces are important optical surfaces, and the wide application and high production rate of spherical surfaces necessitates an accurate and highly reliable measuring device. A Fizeau Interferometer is an appropriate tool for SST due to its subnanometer accuracy. It measures the contour of a spherical surface using a common path, which is insensitive to the surrounding circumstances. The Fizeau Interferometer transmits a wide laser beam, creating interference fringes from re-converging light from the transmission sphere and the test surface. To make a successful measurement, the application calculates and determines the appropriate transmission sphere for the test surface. There are 3 main inputs from the test surfaces that are utilized to determine the optimal sizes and F-numbers of the transmission spheres: (1) the curvatures (concave or convex), (2) the Radii of Curvature (ROC), and (3) the aperture sizes. The application will firstly calculate the F-numbers (i.e. ROC divided by aperture) of the test surface, secondly determine the correct aperture size of a convex surface, thirdly verify that the ROC of the test surface must be shorter than the reference surface's ROC of the transmission sphere, and lastly calculate the percentage of area that the test surface will be measured. However, the amount of interferometers and transmission spheres should be optimized when measuring large spherical surfaces to avoid requiring a large amount of interferometers and transmission spheres for each test surface. Current measuring practices involve tedious and potentially inaccurate calculations. This smart application eliminates human calculation errors, optimizes the selection of transmission spheres (including the least number required) and interferometer sizes, and increases efficiency.
Metabolism and resources of spherical colonies of Nostoc zetterstedtii

DEFF Research Database (Denmark)

Jensen, Kaj Sand; Raun, Ane-Marie Løvendahl; Borum, Jens

2009-01-01

Constraints imposed by the spherical form and gelatinous matrix of centimeter-thick colonies of the cyanobacterium Nostoc zetterstedtii on its functional properties were tested by examining the scaling of its composition, light absorption, photosynthesis, and respiration to individual size....... Nostoc absorbed 96% of incident light from the surface to the center because of high areal pigment density, but absorbed photons were used with low quantum efficiency (11- 38 mmol O2 mol21 photon) and photosynthesis was low relative to dark respiration (2.0-5.4). Therefore, N. zetterstedtii is threatened...... by reduced light availability and only extended to lake depths receiving about 12% of surface irradiance, whereas mosses, characeans, and angiosperms with thin photosynthetic tissues grew deeper (3.1-7.5% of surface irradiance). Nostoc ameliorated the restrictions of low lake DIC and long diffusion paths...
Porous spherical shells and microspheres by electrodispersion precipitation

International Nuclear Information System (INIS)

Harris, M.T.; Sisson, W.G.; Basaran, O.A.; Hayes, S.M.; Bobrowski, S.J.

1994-01-01

The ability to reproduce the synthesis of dense- and porous-microspheres and micron-sized spherical shells is very important in (a) the development of ceramics for structural, electronic, catalyst and thermal applications; and (b) the encapsulation of products for controlled-release of drugs, flavors and perfumes, and inks and dyes, and the protection of light-sensitive components and mechanical support of fragile materials. Larger metallic- and ceramic-spherical shells have been used in inertial confinement fusion (ICF) experiments and as catalyst supports. The current paper will focus on a recent technique that has been developed for synthesizing ceramic microspheres and micro-shells. Pulsed electric fields have been used to enhance the dispersion of aqueous metal (Zr and Al) salt solutions from a nozzle and into a nonconducting liquid continuous phase that is immiscible with the aqueous phase. The diameter of the resulting microdroplets ranged in size from approximately 0.1 to 10 μm. Precipitation of hydrous metal oxides occurred as ammonia, which was dissolved in varying amounts in the continuous phase, diffused into the aqueous microdroplets. Spherical shells were formed at higher ammonia concentrations and microspheres were produced at lower ammonia concentrations. Upon drying, dimples appeared in the particles that were synthesized at higher ammonia concentrations. The latter result accords with the well known fact that under certain conditions spherical shells collapse when a fluid is extracted from the core of the particle. No dimples were observed in the microspheres that were produced at lower ammonia concentrations. Analog X-ray dot maps for aluminum and zirconium were done to determine the spatial distribution of each metal in the particles
Friction factor for water flow through packed beds of spherical and non-spherical particles

Directory of Open Access Journals (Sweden)

Kaluđerović-Radoičić Tatjana

2017-01-01

Full Text Available The aim of this work was the experimental evaluation of different friction factor correlations for water flow through packed beds of spherical and non-spherical particles at ambient temperature. The experiments were performed by measuring the pressure drop across the bed. Packed beds made of monosized glass spherical particles of seven different diameters were used, as well as beds made of 16 fractions of quartz filtration sand obtained by sieving (polydisperse non-spherical particles. The range of bed voidages was 0.359–0.486, while the range of bed particle Reynolds numbers was from 0.3 to 286 for spherical particles and from 0.1 to 50 for non-spherical particles. The obtained results were compared using a number of available literature correlations. In order to improve the correlation results for spherical particles, a new simple equation was proposed in the form of Ergun’s equation, with modified coefficients. The new correlation had a mean absolute deviation between experimental and calculated values of pressure drop of 9.04%. For non-spherical quartz filtration sand particles the best fit was obtained using Ergun’s equation, with a mean absolute deviation of 10.36%. Surface-volume diameter (dSV necessary for correlating the data for filtration sand particles was calculated based on correlations for dV = f(dm and Ψ = f(dm. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON172022
What do mirror neurons mirror?

NARCIS (Netherlands)

Uithol, S.; Rooij, I.J.E.I. van; Bekkering, H.; Haselager, W.F.G.

2011-01-01

Single cell recordings in monkeys provide strong evidence for an important role of the motor system in action understanding. This evidence is backed up by data from studies of the (human) mirror neuron system using neuroimaging or TMS techniques, and behavioral experiments. Although the data
Ultra-light-weight high torque density brushless PM machine design: considering driving-cycle of a four-wheel drive race car (EVER15-138)

NARCIS (Netherlands)

Paulides, J.J.H.; Encica, L.; Beernaert, T.F.; Velden, van der H.H.F.; Parfant, A.G.P.; Lomonova, E.A.

2015-01-01

This paper explores the design of an ultra-light-weight power and torque dense motor to enhance the performance of a light-weight electric racing vehicle. Such a racing vehicle is to compete in formula student racing events. The state-of-the-art powertrain in these vehicles are axial-field machines
Thin Mirror Shaping Technology for High-Throughput X-ray Telescopes

Science.gov (United States)

Schattenburg, Mark

This proposal is submitted to the NASA Research Opportunities in Space and Earth Sciences program (ROSES-2012) in response to NASA Research Announcement NNH12ZDA001N- APRA. It is targeted to the Astronomy and Astrophysics Research and Analysis (APRA) program element under the Supporting Technology category. Powerful x-ray telescope mirrors are critical components of a raft of small-to-large mission concepts under consideration by NASA. The science questions addressed by these missions have certainly never been more compelling and the need to fulfill NASA s core missions of exploring the universe and strengthening our nation s technology base has never been greater. Unfortunately, budgetary constraints are driving NASA to consider the cost/benefit and risk factors of new missions more carefully than ever. New technology for producing x-ray telescopes with increased resolution and collecting area, while holding down cost, are key to meeting these goals and sustaining a thriving high-energy astrophysics enterprise in the US. We propose to develop advanced technology which will lead to thin-shell x-ray telescope mirrors rivaling the Chandra x-ray telescope in spatial resolution but with 10-100X larger area all at significantly reduced weight, risk and cost. The proposed effort builds on previous research at MIT and complements NASA-supported research at other institutions. We are currently pursuing two thin-mirror technology development tracks which we propose to extend and accelerate with NASA support. The first research track utilizes rapidly-maturing thermal glass slumping technology which uses porous ceramic air-bearing mandrels to shape glass mirrors without touching, thus avoiding surface-induced mid-range spatial frequency ripples. A second research track seeks to remove any remaining mid- to long-range errors in mirrors by using scanning ion-beam implant to impart small, highly deterministic and very stable amounts of stress into thin glass, utilizing local
Progress in octahedral spherical hohlraum study

Directory of Open Access Journals (Sweden)

Ke Lan

2016-01-01

Full Text Available In this paper, we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study. From our theoretical study, the octahedral spherical hohlraums with 6 Laser Entrance Holes (LEHs of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7. In addition, the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology. We studied the laser arrangement and constraints of the octahedral spherical hohlraums, and gave a design on the laser arrangement for ignition octahedral hohlraums. As a result, the injection angle of laser beams of 50°–60° was proposed as the optimum candidate range for the octahedral spherical hohlraums. We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields, in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport. We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums, the rugby hohlraums and the cylindrical hohlraums, and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive. Up till to now, we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG laser facilities, including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums, spherical hohlraum energetics on the SGIII prototype laser facility, and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.
Advanced Mirror & Modelling Technology Development

Science.gov (United States)

Effinger, Michael; Stahl, H. Philip; Abplanalp, Laura; Maffett, Steven; Egerman, Robert; Eng, Ron; Arnold, William; Mosier, Gary; Blaurock, Carl

2014-01-01

The 2020 Decadal technology survey is starting in 2018. Technology on the shelf at that time will help guide selection to future low risk and low cost missions. The Advanced Mirror Technology Development (AMTD) team has identified development priorities based on science goals and engineering requirements for Ultraviolet Optical near-Infrared (UVOIR) missions in order to contribute to the selection process. One key development identified was lightweight mirror fabrication and testing. A monolithic, stacked, deep core mirror was fused and replicated twice to achieve the desired radius of curvature. It was subsequently successfully polished and tested. A recently awarded second phase to the AMTD project will develop larger mirrors to demonstrate the lateral scaling of the deep core mirror technology. Another key development was rapid modeling for the mirror. One model focused on generating optical and structural model results in minutes instead of months. Many variables could be accounted for regarding the core, face plate and back structure details. A portion of a spacecraft model was also developed. The spacecraft model incorporated direct integration to transform optical path difference to Point Spread Function (PSF) and between PSF to modulation transfer function. The second phase to the project will take the results of the rapid mirror modeler and integrate them into the rapid spacecraft modeler.
Issues facing the U. S. mirror program

Energy Technology Data Exchange (ETDEWEB)

George, T.V.

1978-07-01

Some of the current issues associated with the U.S. Magnetic Mirror Program are analyzed. They are presented as five separate papers entitled: (1) Relevant Issues Broughtup by the Mirror Reactor Design Studies. (2) An Assessment of the Design Study of the 1 MeV Neutral Beam Injector Required for a Tandem Mirror Reactor. (3) The Significance of the Radial Plasma Size Measured in Units of Ion Gyroradii in Tandem Mirrors and Field Reversed Mirrors. (4) Producing Field Reversed Mirror Plasmas by Methods used in Field Reversed Theta Pinch. (5) RF Stoppering of Mirror Confined Plasma.
Analysis of a four-mirror-cavity enhanced Michelson interferometer.

Science.gov (United States)

Thüring, André; Lück, Harald; Danzmann, Karsten

2005-12-01

We investigate the shot-noise-limited sensitivity of a four-mirror-cavity enhanced Michelson interferometer. The intention of this interferometer topology is the reduction of thermal lensing and the impact of the interferometers contrast although transmissive optics are used with high circulating powers. The analytical expressions describing the light fields and the frequency response are derived. Although the parameter space has 11 dimensions, a detailed analysis of the resonance feature gives boundary conditions allowing systematic parameter studies.
Influence of light-weight organic matters on strontium sorption to bentonite

International Nuclear Information System (INIS)

Wang, Tsing-Hai; Wu, Ding-Chiang; Teng, Shi-Ping

2010-01-01

Document available in extended abstract form only. Light-weight organic matters were frequently observed in groundwater. Their existence had significant influence on the transport of radionuclides. In this study, light-weight organic acid species including oxalic (MW 90), succinic (MW 118), adipic (MW 146), azelaic (MW 188), eicosanedioic (MW 306), benzoic (MW 122), salicylic (MW 138), and gallic (MW 170) were selected as the surrogate of natural organic matters. Their effects on strontium sorption to bentonite were evaluated by using a surface complexation model MINEQL+. Under this framework, three sorption mechanisms were considered: 1. structure sorption sites, 2. edge sorption sites, 3. further hydration of adsorbed Sr 2+ . The presence of organic species had no influence on Sr cation sorption to structure sorption sites. However, Sr cation sorption to edge sorption was affected by the organics to certain extent. For example, sorption capability of edge sites toward Sr was increased by the gallic species. Furthermore, hydration of adsorbed Sr was significantly affected by the presence of organic species. This might relate to that adsorbed Sr would become the bridge associating organic species on bentonite surfaces, but this argument required more solid spectral evidences to support. Some preliminary observations on Sr sorption to bentonite were obtained in this work; however, further experiments are still required by conducting experiments with more variety of organic species. By doing a comprehensive study, it would be much beneficial to make a more accurate evaluation of the influence of organic matters on Sr sorption
Mirror reactor surface study

Energy Technology Data Exchange (ETDEWEB)

Hunt, A. L.; Damm, C. C.; Futch, A. H.; Hiskes, J. R.; Meisenheimer, R. G.; Moir, R. W.; Simonen, T. C.; Stallard, B. W.; Taylor, C. E.

1976-09-01

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included.
Transmission X-ray mirror

International Nuclear Information System (INIS)

Lairson, B.M.; Bilderback, D.H.

1982-01-01

Transmission X-ray mirrors have been made from 400 A to 10 000 A thick soap films and have been shown to have novel properties. Using grazing angles of incidence, low energy X-rays were reflected from the front surface while more energetic X-rays were transmitted through the mirror largely unattenuated. A wide bandpass monochromator was made from a silicon carbide mirror followed by a soap film transmission mirror and operated in the white beam at the cornell High Energy Synchrotron Source (CHESS). Bandpasses of ΔE/E=12% to 18% were achieved at 13 keV with peak efficiencies estimated to be between 55% and 75%, respectively. Several wide angle scattering photographs of stretched polyethylene and a phospholipid were obtained in 10 s using an 18% bandpass. (orig.)

Mirror reactor surface study

International Nuclear Information System (INIS)

Hunt, A.L.; Damm, C.C.; Futch, A.H.; Hiskes, J.R.; Meisenheimer, R.G.; Moir, R.W.; Simonen, T.C.; Stallard, B.W.; Taylor, C.E.

1976-01-01

A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included
Carambola optics for recycling of light.

Science.gov (United States)

Leutz, Ralf; Fu, Ling; Ries, Harald

2006-04-20

Recycling of light allows the luminance (radiance) emitted by a light source to be increased at the cost of reducing the total luminous flux (radiant power). Recycling of light means returning part of the emitted light to the source, where part of it will escape absorption. An optical design that is suitable for multiple and controlled recycling is described. Carambola optics is named for its resemblance to star fruit. Several pairs of mirrors or prisms redirect light repeatedly onto the source, thus achieving multiple transits of the light through the source. This recycled light exits the carambola in the same phase space as light directly emitted and not recycled.
Introduction to tandem mirror physics

International Nuclear Information System (INIS)

Kesner, J.; Gerver, M.J.; Lane, B.G.; McVey, B.D.; Catto, P.J.; D'Ippolito, D.A.; Myra, J.R.

1983-09-01

This monograph, prepared jointly by the MIT Plasma Fusion Center Mirror Fusion group and SAI, Boulder, Colorado, presents a review of the development of mirror fusion theory from its conception some thirty years ago to the present. Pertinent historic experiments and their contribution are discussed to set the stage for a detailed analysis of current experiments and the problems which remain to be solved in bringing tandem mirror magnetic confinement fusion to fruition. In particular, Chapter III discusses in detail the equilibrium and stability questions which must be dealt with before tandem mirror reactors become feasible, while Chapters IV and V discuss some of the current machines and those under construction which will help to resolve critical issues in both physics and engineering whose solutions are necessary to the commercialization of tandem mirror fusion
LLL mirror fusion program: summary

International Nuclear Information System (INIS)

Fowler, T.K.

1977-01-01

During 1976, new Mirror Program plans have been laid out to take into account the significant advances during the last 18 months. The program is now focused on two new mirror concepts, field reversal and the tandem mirror, that can obtain high Q, defined as the ratio of fusion power output to the neutral-beam power injected to sustain the reaction. Theoretically, both concepts can attain Q = 5 or more, as compared to Q = 1 in previous mirror designs. Experimental planning for the next 5 years is complete in broad outline, and we are turning attention to what additional steps are necessary to reach our long-range goal of an experimental mirror reactor operating by 1990. Highlights of the events that have led to the above circumstance are listed, and experimental program plans are outlined
ODF Maxima Extraction in Spherical Harmonic Representation via Analytical Search Space Reduction

Science.gov (United States)

Aganj, Iman; Lenglet, Christophe; Sapiro, Guillermo

2015-01-01

By revealing complex fiber structure through the orientation distribution function (ODF), q-ball imaging has recently become a popular reconstruction technique in diffusion-weighted MRI. In this paper, we propose an analytical dimension reduction approach to ODF maxima extraction. We show that by expressing the ODF, or any antipodally symmetric spherical function, in the common fourth order real and symmetric spherical harmonic basis, the maxima of the two-dimensional ODF lie on an analytically derived one-dimensional space, from which we can detect the ODF maxima. This method reduces the computational complexity of the maxima detection, without compromising the accuracy. We demonstrate the performance of our technique on both artificial and human brain data. PMID:20879302
Impact of design-parameters on the optical performance of a highpower adaptive mirror

NARCIS (Netherlands)

Koek, W.D.; Nijkerk, M.D.; Smeltink, J.A.; Dool, T.C. van den; Zwet, E.J. van; Baars, G.E. van

2017-01-01

TNO is developing a High Power Adaptive Mirror (HPAM) to be used in the CO2 laser beam path of an Extreme Ultra-Violet (EUV) light source for next-generation lithography. In this paper we report on a developed methodology, and the necessary simulation tools, to assess the performance and associated
Advances in telescope mirror cleaning

Science.gov (United States)

Blanken, Maarten F.; Chopping, Alan K.; Dee, Kevin M.

2004-09-01

Metrology and cleaning techniques for telescope mirrors are generally well established. CO2 cleaning and water washing are mainly used. Water washing has proven to be the best method of removing oil and water stains and restoring the aluminium to nearly fresh values. The risk of water getting to unwanted places such as electronics or other optics prevents this method from being employed more often. Recently the Isaac Newton Group introduced a new cleaning technique for their telescope mirrors, which reduces the risks discussed above. This technique uses water vapour instead of water to wash the mirror. The advantage of this method is that the amount of water needed is drastically reduced. In addition the pressure of the vapour will blow away any large dust particles on the mirror and the temperature shock between the vapour and the mirror will help to de-bond the dust particles. Adding a soapy solution will help to clean oil and watermarks of the mirror. This paper describes the vapour cleaning method, tests that have been done and the overall findings.
Evaluation of physical property of light-weight soil with air foam using X-ray CT method

International Nuclear Information System (INIS)

Otani, Jun; Mukunoki, Toshifumi; Kikuchi, Yoshiaki

2000-01-01

The objective of this paper is to investigate the physical property of light-weight soil made of dredged slurry mixed with air foam and cement using X-ray CT method. In this study, not only the specimen made in laboratory but also the one sampled at the in-situ construction site were used and the property in the soil was visualized and the distributions of the density an air porosity were evaluated quantitatively using the results of CT scanning. Here, the method of image processing analysis was also used for this evaluation study. Based on the results obtained in this study, it is concluded that the X-ray CT method is a powerful tool even for geotechnical engineering and this makes not only the visualization but also the quantitative ion discussion possible for the light-weight soil with air foam. (author)
Mirror fusion--fission hybrids

International Nuclear Information System (INIS)

Lee, J.D.

1978-01-01

The fusion-fission concept and the mirror fusion-fission hybrid program are outlined. Magnetic mirror fusion drivers and blankets for hybrid reactors are discussed. Results of system analyses are presented and a reference design is described
Light weight radioisotope heater unit (LWRHU) production for the Cassini mission

International Nuclear Information System (INIS)

Rinehart, G.H.

1997-01-01

The Light-Weight Radioisotope Heater Unit (LWRHU) is a [sup 238]PuO[sub 2] fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. The heat sources are required to maintain the temperature of specific components within normal operating ranges. The heat source consists of a hot- pressed [sup 238]PuO[sub 2] fuel pellet, a Pt-3ORh vented capsule, a pyrolytic graphite insulator, and a woven graphite aeroshell assembly. Los Alamos National Laboratory has fabricated 180 heat sources, 157 of which will be used on the Cassini mission
Effects of lighting and air-conditioning systems on growth weight and functional composition of frill-lettuce produced in plant factory

Science.gov (United States)

Yoshida, Atsumasa; Okamura, Nobuya; Furukawa, Hajime; Myojin, Chiho; Moriuchi, Koji; Kinoshita, Shinichi

2017-06-01

The aim of the present study was to develop optimal air-conditioning systems for plant factories. To verify the effect of particular air-conditioning and lighting systems, cultivation experiments were performed with frill-lettuce for two weeks. In the present study, the relationship between the cultivation condition, the yield (i.e., increase in edible portion weight), and the functional components were discussed. Based on the measured data, increased photosynthetic photon flux density increased antioxidative activity and edible portion weight, possibly because high light intensities are stressful for frill lettuce. Antioxidative activity also increased under conditions of low CO2 concentration, weak and strong winds, and high air temperature because these conditions became stresses for the plants. However, a decrease in edible portion weight was observed under these conditions, implying there is a negative correlation between antioxidative activity and edible portion weight.
Optical scanning holography based on compressive sensing using a digital micro-mirror device

Science.gov (United States)

A-qian, Sun; Ding-fu, Zhou; Sheng, Yuan; You-jun, Hu; Peng, Zhang; Jian-ming, Yue; xin, Zhou

2017-02-01

Optical scanning holography (OSH) is a distinct digital holography technique, which uses a single two-dimensional (2D) scanning process to record the hologram of a three-dimensional (3D) object. Usually, these 2D scanning processes are in the form of mechanical scanning, and the quality of recorded hologram may be affected due to the limitation of mechanical scanning accuracy and unavoidable vibration of stepper motor's start-stop. In this paper, we propose a new framework, which replaces the 2D mechanical scanning mirrors with a Digital Micro-mirror Device (DMD) to modulate the scanning light field, and we call it OSH based on Compressive Sensing (CS) using a digital micro-mirror device (CS-OSH). CS-OSH can reconstruct the hologram of an object through the use of compressive sensing theory, and then restore the image of object itself. Numerical simulation results confirm this new type OSH can get a reconstructed image with favorable visual quality even under the condition of a low sample rate.
Where do mirror neurons come from?

Science.gov (United States)

Heyes, Cecilia

2010-03-01

Debates about the evolution of the 'mirror neuron system' imply that it is an adaptation for action understanding. Alternatively, mirror neurons may be a byproduct of associative learning. Here I argue that the adaptation and associative hypotheses both offer plausible accounts of the origin of mirror neurons, but the associative hypothesis has three advantages. First, it provides a straightforward, testable explanation for the differences between monkeys and humans that have led some researchers to question the existence of a mirror neuron system. Second, it is consistent with emerging evidence that mirror neurons contribute to a range of social cognitive functions, but do not play a dominant, specialised role in action understanding. Finally, the associative hypothesis is supported by recent data showing that, even in adulthood, the mirror neuron system can be transformed by sensorimotor learning. The associative account implies that mirror neurons come from sensorimotor experience, and that much of this experience is obtained through interaction with others. Therefore, if the associative account is correct, the mirror neuron system is a product, as well as a process, of social interaction. (c) 2009 Elsevier Ltd. All rights reserved.
Thermal Analysis of the Advanced Technology Large Aperture Space Telescope (ATLAST) 8 Meter Primary Mirror

Science.gov (United States)

Hornsby, Linda; Stahl, H. Philip; Hopkins, Randall C.

2010-01-01

The Advanced Technology Large Aperture Space Telescope (ATLAST) preliminary design concept consists of an 8 meter diameter monolithic primary mirror enclosed in an insulated, optical tube with stray light baffles and a sunshade. ATLAST will be placed in orbit about the Sun-Earth L2 and will experience constant exposure to the sun. The insulation on the optical tube and sunshade serve to cold bias the telescope which helps to minimize thermal gradients. The primary mirror will be maintained at 280K with an active thermal control system. The geometric model of the primary mirror, optical tube, sun baffles, and sunshade was developed using Thermal Desktop(R) SINDA/FLUINT(R) was used for the thermal analysis and the radiation environment was analyzed using RADCAD(R). A XX node model was executed in order to characterize the static performance and thermal stability of the mirror during maneuvers. This is important because long exposure observations, such as extra-solar terrestrial planet finding and characterization, require a very stable observatory wave front. Steady state thermal analyses served to predict mirror temperatures for several different sun angles. Transient analyses were performed in order to predict thermal time constant of the primary mirror for a 20 degree slew or 30 degree roll maneuver. This paper describes the thermal model and provides details of the geometry, thermo-optical properties, and the environment which influences the thermal performance. All assumptions that were used in the analysis are also documented. Parametric analyses are summarized for design parameters including primary mirror coatings and sunshade configuration. Estimates of mirror heater power requirements are reported. The thermal model demonstrates results for the primary mirror heated from the back side and edges using a heater system with multiple independently controlled zones.
Mirror matter as self-interacting dark matter

International Nuclear Information System (INIS)

Mohapatra, R.N.; Nussinov, S.; Teplitz, V.L.

2002-01-01

It has been argued that the observed core density profile of galaxies is inconsistent with having a dark matter particle that is collisionless and that alternative dark matter candidates which are self-interacting may explain observations better. One new class of self-interacting dark matter that has been proposed in the context of mirror universe models of particle physics is the mirror hydrogen atom, whose stability is guaranteed by the conservation of mirror baryon number. We show that the effective transport cross section for mirror hydrogen atoms has the right order of magnitude for solving the 'cuspy' halo problem. Furthermore, the suppression of dissipation effects for mirror atoms due to a higher mirror mass scale prevents the mirror halo matter from collapsing into a disk, strengthening the argument for mirror matter as galactic dark matter
Graded Mirror Self-Recognition by Clark's Nutcrackers.

Science.gov (United States)

Clary, Dawson; Kelly, Debbie M

2016-11-04

The traditional 'mark test' has shown some large-brained species are capable of mirror self-recognition. During this test a mark is inconspicuously placed on an animal's body where it can only be seen with the aid of a mirror. If the animal increases the number of actions directed to the mark region when presented with a mirror, the animal is presumed to have recognized the mirror image as its reflection. However, the pass/fail nature of the mark test presupposes self-recognition exists in entirety or not at all. We developed a novel mirror-recognition task, to supplement the mark test, which revealed gradation in the self-recognition of Clark's nutcrackers, a large-brained corvid. To do so, nutcrackers cached food alone, observed by another nutcracker, or with a regular or blurry mirror. The nutcrackers suppressed caching with a regular mirror, a behavioural response to prevent cache theft by conspecifics, but did not suppress caching with a blurry mirror. Likewise, during the mark test, most nutcrackers made more self-directed actions to the mark with a blurry mirror than a regular mirror. Both results suggest self-recognition was more readily achieved with the blurry mirror and that self-recognition may be more broadly present among animals than currently thought.
Mirror neurons: from origin to function.

Science.gov (United States)

Cook, Richard; Bird, Geoffrey; Catmur, Caroline; Press, Clare; Heyes, Cecilia

2014-04-01

This article argues that mirror neurons originate in sensorimotor associative learning and therefore a new approach is needed to investigate their functions. Mirror neurons were discovered about 20 years ago in the monkey brain, and there is now evidence that they are also present in the human brain. The intriguing feature of many mirror neurons is that they fire not only when the animal is performing an action, such as grasping an object using a power grip, but also when the animal passively observes a similar action performed by another agent. It is widely believed that mirror neurons are a genetic adaptation for action understanding; that they were designed by evolution to fulfill a specific socio-cognitive function. In contrast, we argue that mirror neurons are forged by domain-general processes of associative learning in the course of individual development, and, although they may have psychological functions, they do not necessarily have a specific evolutionary purpose or adaptive function. The evidence supporting this view shows that (1) mirror neurons do not consistently encode action "goals"; (2) the contingency- and context-sensitive nature of associative learning explains the full range of mirror neuron properties; (3) human infants receive enough sensorimotor experience to support associative learning of mirror neurons ("wealth of the stimulus"); and (4) mirror neurons can be changed in radical ways by sensorimotor training. The associative account implies that reliable information about the function of mirror neurons can be obtained only by research based on developmental history, system-level theory, and careful experimentation.
Helically linked mirror arrangement

International Nuclear Information System (INIS)

Ranjan, P.

1986-08-01

A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average β and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned
Multiple-mirror plasma confinement

International Nuclear Information System (INIS)

Lichtenberg, A.J.; Lieberman, M.A.; Logan, B.G.

1975-01-01

A large enhancement of the confinement time can be achieved in a straight system of multiple mirrors over an equal length uniform magnetic field. The scaling is diffusive rather than that of flow, thereby scaling the square of the system length rather than linear with system length. Probably the most economic mode of operation for a reactor occurs when lambda/M is approximately l/sub c/, where lambda is the mean free path, M the mirror ratio, and l/sub c/ the length between mirrors; but where the scale length of the mirror field l/sub m/ is much less than lambda. The axial confinement time has been calculated theoretically and numerically for all important parameter regimes, and confirmed experimentally. A typical reactor calculation gives Q/sub E/ = 2 for a 400 meter system with 3000 MW(e) output. The main concern of a multiple-mirror system is stability. Linked quadrupoles can achieve average minimum-B stabilization of flute modes, and experiments have demonstrated this stabilization. Localized instabilities at finite β and enhanced diffusion resulting from the distorted flux surfaces and possibly from turbulent higher order modes still remain to be investigated
Matlab fractal techniques used to study the structural degradation caused by alpha radiation to laser mirrors

Science.gov (United States)

Ioan, M.-R.

2018-01-01

Almost all optical diagnostic systems associated with classical particle accelerators or with new state-of-the-art particle accelerators, such as those developed within the European Collaboration ELI-NP (Extreme Light Infrastructure-Nuclear Physics) (involving extreme power laser beams), contain in their infrastructure high quality laser mirrors, used for their reflectivity and/or their partial transmittance. These high quality mirrors facilitate the extraction and handling of optical signals. When optical mirrors are exposed to high energy ionizing radiation fields, their optical and structural properties will change over time and their functionality will be affected, meaning that they will provide imprecise information. In some experiments, being exposed to mixed laser and accelerated particle beams, the deterioration of laser mirrors is even more acute, since the destruction mechanisms of both types of beams are cumulated. The main task of the work described in this paper was to find a novel specific method to analyse and highlight such degradation processes. By using complex fractal techniques integrated in a MATLAB code, the effects induced by alpha radiation to laser mirrors were studied. The fractal analysis technique represents an alternative approach to the classical Euclidean one. It can be applied for the characterization of the defects occurred in mirrors structure due to their exposure to high energy alpha particle beams. The proposed method may be further integrated into mirrors manufacturing process, as a testing instrument, to obtain better quality mirrors (enhanced resistance to high energy ionizing beams) by using different types of reflective coating materials and different deposition techniques. Moreover, the effect of high energy alpha ionizing particles on the optical properties of the exposed laser mirrors was studied by using spectrophotometric techniques.

Magnetic mirror fusion: status and prospects

International Nuclear Information System (INIS)

Post, R.F.

1980-01-01

Two improved mirror systems, the tandem mirror (TM) and the field-reversed mirror (FRM) are being intensively studied. The twin practical aims of these studies: to improve the economic prospects for mirror fusion power plants and to reduce the size and/or complexity of such plants relative to earlier approaches to magnetic fusion. While at the present time the program emphasis is still strongly oriented toward answering scientific questions, the emphasis is shifting as the data accumulates and as larger facilities - ones with a heavy technological and engineering orientation - are being prepared. The experimental and theoretical progress that led to the new look in mirror fusion research is briefly reviewed, the new TM and the FRM ideas are outlined, and the projected future course of mirror fusion research is discussed
Weight reduction of automobile parts using light metals. Keikinzoku shiyo ni yoru jidosha buhin no keiryoka

Energy Technology Data Exchange (ETDEWEB)

Hayashi, S [Toyota Motor Corp., Aichi (Japan)

1992-12-25

Weight reduction of automobiles is required from the viewpoint of reduction of CO2 emission and energy conservation. Comparing a car with another one of almost the same size and performance with 1% reduced weight, combustion efficiency of the latter can be improved by 0.5-0.8%. This report introduces several examples, in which steel parts are replaced with light alloy parts to reduce car weight, and describes the future perspective. Concerning a cylinder block which is the heaviest part among engine parts, a block made of aluminum alloy with no cast liner has been developed. There is also an example of an oil pan adopting aluminum die-cast for a part of it. A valve lifter made of aluminum alloy has been developed for valve system parts and has contributed to friction loss, noise reduction, and improvement of fuel consumption. As for steering system parts, a steering bracket made of Mg alloy die-cast has been developed. The use of light alloy parts, in general, increases material cost. Therefore it is now required to build up closer connection between designs and production techniques and to improve reliability of casting and forging technologies. 5 refs., 20 figs.
Design optimization on the drive train of a light-weight robotic arm

DEFF Research Database (Denmark)

Zhou, Lelai; Bai, Shaoping; Hansen, Michael Rygaard

2011-01-01

A drive train optimization method for design of light-weight robots is proposed. Optimal selections of motors and gearboxes from a limited catalog of commercially available components are done simultaneously for all joints of a robotic arm. Characteristics of the motor and gearbox, including gear...... ratio, gear inertia, motor inertia, and gear efficiency, are considered in the drive train modeling. A co-simulation method is developed for dynamic simulation of the arm. A design example is included to demonstrate the proposed design optimization method....
Ultra High Temperature and Multifunctional Ceramic Matrix Composite – Coating Systems for Light-Weight Space and Aero Systems

Data.gov (United States)

National Aeronautics and Space Administration — Revolutionary ultra-high temperature, high mechanical loading capable, oxidation resistant, durable ceramic coatings and light-weight fiber-reinforced Ceramic Matrix...
Atmospheric profiles of Black Carbon at remote locations using light-weight airborne Aethalometers

Science.gov (United States)

Hansen, A. D.; Močnik, G.; Drinovec, L.; Lenarcic, M.

2012-12-01

While measurements of atmospheric aerosols are routinely performed at ground-level around the world, there is far less knowledge of their concentrations at altitude: yet this data is a crucial requirement for our understanding of the dispersion of pollutants of anthropogenic origin, with their associated effects on radiative forcing, cloud condensation, and other adverse phenomena. Black Carbon (BC) is a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. It has no non-combustion sources and is not transformed by atmospheric processes. Recent technical advances have developed light-weight miniaturized instruments which can be operated on light aircraft or carried aboard commercial passenger flights. From January to April 2012, a single-seat ultra-light aircraft flew around the world on a scientific, photographic and environmental-awareness mission. The flight track crossed all seven continents and all major oceans, with altitudes up to 8.9 km ASL. The aircraft carried a custom-developed high-sensitivity dual-wavelength light-weight Aethalometer, operating at 370 and 880 nm with special provision to compensate for the effects of changing pressure, temperature and humidity. The instrument recorded BC concentrations with high temporal resolution and sensitivity better than 5 ng/m3. We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas, analyzing the spectral dependence of absorption to infer the contributions to BC from fossil fuel vs. biomass combustion, and aggregating the data into vertical profiles. The regional and long range transport of BC may be investigated using back-trajectories. We have also operated miniature instruments in the passenger cabins of long-distance commercial aircraft. Since there are no combustion sources within the cabin, any BC in the ventilation air must necessarily have originated from the outside
Effects of mirror symmetry on the transmission fingerprints of quasiperiodic photonic multilayers

Energy Technology Data Exchange (ETDEWEB)

Coelho, I.P. [Departamento de Ensino Superior, Instituto Federal de Educacao, Ciencia e Tecnologia do Maranhao, Campus Imperatriz, 65919-050 Imperatriz, MA (Brazil); Vasconcelos, M.S., E-mail: mvasconcelos@ect.ufrn.b [Escola de Ciencias e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Bezerra, C.G. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil)

2010-03-29

We address the transmission properties of light waves through symmetric Fibonacci, Thue-Morse and double-period photonic multilayers, i.e., a binary one-dimensional quasiperiodic structure made up of two different dielectric materials (more specifically SiO{sub 2} and TiO{sub 2}), in quarter wavelength condition, presenting mirror symmetry. The optical spectra are calculated by using a theoretical model based on the transfer matrix approach in normal incidence geometry. In our results we present the self-similar features of the spectra and we also present the optical fingerprints through a return map of the transmission coefficients. We discuss these optical fingerprints and compare them with results of previous works, on similar quasiperiodic systems, in the absence of mirror symmetry.
Laser cleaning of ITER's diagnostic mirrors

Science.gov (United States)

Skinner, C. H.; Gentile, C. A.; Doerner, R.

2012-10-01

Practical methods to clean ITER's diagnostic mirrors and restore reflectivity will be critical to ITER's plasma operations. We report on laser cleaning of single crystal molybdenum mirrors coated with either carbon or beryllium films 150 - 420 nm thick. A 1.06 μm Nd laser system provided 220 ns pulses at 8 kHz with typical power densities of 1-2 J/cm^2. The laser beam was fiber optically coupled to a scanner suitable for tokamak applications. The efficacy of mirror cleaning was assessed with a new technique that combines microscopic imaging and reflectivity measurements [1]. The method is suitable for hazardous materials such as beryllium as the mirrors remain sealed in a vacuum chamber. Excellent restoration of reflectivity for the carbon coated Mo mirrors was observed after laser scanning under vacuum conditions. For the beryllium coated mirrors restoration of reflectivity has so far been incomplete and modeling indicates that a shorter duration laser pulse is needed. No damage of the molybdenum mirror substrates was observed.[4pt][1] C.H. Skinner et al., Rev. Sci. Instrum. at press.
Mirror image agnosia.

Science.gov (United States)

Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor

2014-10-01

Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles reflected self-images. A new observation involving failure
Compact, Light-weight and Cost-effective Microscope based on Lensless Incoherent Holography for Telemedicine Applications

Science.gov (United States)

Mudanyali, Onur; Tseng, Derek; Oh, Chulwoo; Isikman, Serhan O.; Sencan, Ikbal; Bishara, Waheb; Oztoprak, Cetin; Seo, Sungkyu; Khademhosseini, Bahar; Ozcan, Aydogan

2010-01-01

Despite the rapid progress in optical imaging, most of the advanced microscopy modalities still require complex and costly set-ups that unfortunately limit their use beyond well equipped laboratories. In the meantime, microscopy in resource-limited settings has requirements significantly different from those encountered in advanced laboratories, and such imaging devices should be cost-effective, compact, light-weight and appropriately accurate and simple to be usable by minimally trained personnel. Furthermore, these portable microscopes should ideally be digitally integrated as part of a telemedicine network that connects various mobile health-care providers to a central laboratory or hospital. Toward this end, here we demonstrate a lensless on-chip microscope weighing ~46 grams with dimensions smaller than 4.2cm × 4.2cm × 5.8cm that achieves sub-cellular resolution over a large field of view of ~24 mm2. This compact and light-weight microscope is based on digital in-line holography and does not need any lenses, bulky optical/mechanical components or coherent sources such as lasers. Instead, it utilizes a simple light-emitting-diode (LED) and a compact opto-electronic sensor-array to record lensless holograms of the objects, which then permits rapid digital reconstruction of regular transmission or differential interference contrast (DIC) images of the objects. Because this lensless incoherent holographic microscope has orders-of-magnitude improved light collection efficiency and is very robust to mechanical misalignments it may offer a cost-effective tool especially for telemedicine applications involving various global health problems in resource limited settings. PMID:20401422
[Mirror, mirror of the wall: mirror therapy in the treatment of phantom limbs and phantom limb pain].

Science.gov (United States)

Casale, Roberto; Furnari, Anna; Lamberti, Raul Coelho; Kouloulas, Efthimios; Hagenberg, Annegret; Mallik, Maryam

2015-01-01

Phantom limb and phantom limb pain control are pivotal points in the sequence of intervention to bring the amputee to functional autonomy. The alterations of perception and sensation, the pain of the residual limb and the phantom limb are therefore aspects of amputation that should be taken into account in the "prise en charge" of these patients. Within the more advanced physical therapies to control phantom and phantom limb pain there is the use of mirrors (mirror therapy). This article willfocus on its use and on the possible side effects induced by the lack of patient selection and a conflict of body schema restoration through mirror therapy with concurrent prosthetic training and trauma acceptance. Advice on the need to select patients before treatment decisions, with regard to their psychological as well as clinical profile (including time since amputation and clinical setting), and the need to be aware of the possible adverse effects matching different and somehow conflicting therapeutic approaches, are put forward. Thus a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team that works globally on all patients' problems is fundamental in the management of amputees and phantom limb pain. Further studies and the development of a multidisciplinary network to study this and other applications of mirror therapy are needed.
Towards Relaxing the Spherical Solar Radiation Pressure Model for Accurate Orbit Predictions

Science.gov (United States)

Lachut, M.; Bennett, J.

2016-09-01

The well-known cannonball model has been used ubiquitously to capture the effects of atmospheric drag and solar radiation pressure on satellites and/or space debris for decades. While it lends itself naturally to spherical objects, its validity in the case of non-spherical objects has been debated heavily for years throughout the space situational awareness community. One of the leading motivations to improve orbit predictions by relaxing the spherical assumption, is the ongoing demand for more robust and reliable conjunction assessments. In this study, we explore the orbit propagation of a flat plate in a near-GEO orbit under the influence of solar radiation pressure, using a Lambertian BRDF model. Consequently, this approach will account for the spin rate and orientation of the object, which is typically determined in practice using a light curve analysis. Here, simulations will be performed which systematically reduces the spin rate to demonstrate the point at which the spherical model no longer describes the orbital elements of the spinning plate. Further understanding of this threshold would provide insight into when a higher fidelity model should be used, thus resulting in improved orbit propagations. Therefore, the work presented here is of particular interest to organizations and researchers that maintain their own catalog, and/or perform conjunction analyses.
X-ray imaging with toroidal mirror

International Nuclear Information System (INIS)

Aoki, Sadao; Sakayanagi, Yoshimi

1978-01-01

X-ray imaging is made with a single toroidal mirror or two successive toroidal mirrors. Geometrical images at the Gaussian image plane are described by the ray trace. Application of a single toroidal mirror to small-angle scattering is presented. (author)
Association of light-to-moderate alcohol drinking in pregnancy with preterm birth and birth weight

DEFF Research Database (Denmark)

Strandberg-Larsen, Katrine; Poulsen, Gry; Bech, Bodil Hammer

2017-01-01

Women who drink light-to-moderately during pregnancy have been observed to have lower risk of unfavourable pregnancy outcomes than abstainers. This has been suggested to be a result of bias. In a pooled sample, including 193 747 live-born singletons from nine European cohorts, we examined...... alcohol. This decreased to 39% in 2000–2004, and 14% in 2005–2011. Before 2000, every additional drink was associated with reduced mean birth weight, whereas in 2005–2011, the mean birth weight increased with increasing intake. The period-specific associations between low-to-moderate drinking and birth...
Design of an elliptically bent refocus mirror for the MERLIN beamline at the advanced light source

International Nuclear Information System (INIS)

Kelez, Nicholas; Chuang, Yi-De; Smith-Baumann, Alexis; Franck, Keith; Duarte, R.; Lanzara, A.; Hasan, M.Z.; Dessau, D.S.; Chiang, T.C.; Shen, Z.-X.; Hussain, Zahid

2007-01-01

There is an increasing demand for well-focused beam with high quality imaging of the full field to further explore the potential of novel instruments. For beamlines operating at focal point, mechanical benders have often been used to shape the refocusing mirror into an ideal elliptical cylinder. Unfortunately, the limited number of couplings for these mechanisms requires specific substrate side-shaping, often calculated using beam bending theory [J.H. Underwood, Space Sci. Instrum. 3 (1977) 259; M. Howells et al., Opt. Eng. 39 (2000) 2748; T. Warwick et al., Document available at OSTI website: http://www.osti.gov/energycitations/servlets/purl/842557-JYZCS3/native/], to meet demanding figure requirements. Here, we use finite element analysis (FEA) to validate the side-shaping algorithm and then couple the output with SHADOW to evaluate mirror performance when an ideal ellipse is not achieved
Are Nanoparticles Spherical or Quasi-Spherical?

Science.gov (United States)

Sokolov, Stanislav V; Batchelor-McAuley, Christopher; Tschulik, Kristina; Fletcher, Stephen; Compton, Richard G

2015-07-20

The geometry of quasi-spherical nanoparticles is investigated. The combination of SEM imaging and electrochemical nano-impact experiments is demonstrated to allow sizing and characterization of the geometry of single silver nanoparticles. © 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.
Viability study of porous silicon photonic mirrors as secondary reflectors for solar concentration systems

Energy Technology Data Exchange (ETDEWEB)

de la Mora, M.B.; Jaramillo, O.A.; Nava, R.; Tagueena-Martinez, J. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, A. P. 34, 62580 Temixco, Morelos (Mexico); del Rio, J.A. [Centro Morelense de Innovacion y Transferencia Tecnologica, CCyTEM Camino Temixco a Emiliano Zapata, Km 0.3, Colonia Emiliano Zapata, 62760 Morelos (Mexico)

2009-08-15

In this paper we report the viability of using porous silicon photonic mirrors (PSPM) as secondary reflectors in solar concentration systems. The PSPM were fabricated with nanostructured porous silicon to reflect light from the visible range to the near infrared region (500-2500 nm), although this range could be tuned for specific wavelength applications. Our PSPM are multilayers of two alternated refractive indexes (1.5 and 2.0), where the condition of a quarter wavelength in the optical path was imposed. The PSPM were exposed to high radiation in a solar concentrator equipment. As a result, we observed a significant degradation of the mirrors at an approximated temperature of 900 C. In order to analyze the origin of the degradation of PSPM, we model the samples with a non-linear optical approach and study the effect of a temperature increase. Those theoretical and experimental studies allow us to conclude that the main phenomenon involved in the breakdown of the photonic mirrors is of thermal origin, produced by heterogeneous expansion of each layer. Our next step was to introduce a cooling system into the solar concentrator to keep the mirrors at approximately 70 C, with very good results. As a conclusion we propose the use of PSPM as selective secondary mirrors in solar concentration devices using temperature control to avoid thermal degradation. (author)
Ultra light weight refractory material for high temperature applications

Energy Technology Data Exchange (ETDEWEB)

Finke, V.; Kern, H. [Rath GmbH, Meissen (Germany); Springer, M. [Aug. Rath jun. GmbH, Vienna (Austria)

2007-07-01

The requirements on companies running high temperature processes, i.e. at temperatures about 1000 C and above, have increased dramatically within the last few years. For technological, economical and ecological purposes each application has to be checked carefully. As well the political discussion regarding environmental pollution, greenhouse effect and emission trading and the guidelines for climate and environmental protection exert massive influence on thermal process technology and pose an appropriate challenge for the companies. Next to costs of labour and raw materials the costs for energy and environmental costs play a decisive role more and more. The pressure on the management thereby incurred may have a lasting effect on innovations regarding increase of energy efficiency, decrease of CO{sub 2}-emission and often on non negligible increase of productivity. Mainly against the background of the highly scheduled European aims for emission reduction and also in consideration of the still proceeding globalisation the usage of state-of-the-art refractory technics in thermal process technology is of particular importance for business success, for reducing of environmental impact and last but not least for conservation and safeguarding of jobs in Europe and Germany. The applications for products made from high-temperature insulation wool in high temperature applications have strongly increased during the last five years. Especially the production capacities of polycrystalline wool (aluminium oxide wool e.g. Altra B72) have been doubled within the last three years. Primarily ultra light weight products made from HTIW are used in industrial furnaces with application temperatures above 1000 C and / or with high thermo-mechanical (thermal shock) and chemical exposure. The outstanding and essential advantages of these materials are obviously: Ultra light weight material with high resilience and flexibility, Optimised energy consumption (energy saving up to 50% compared
Passivation coating for flexible substrate mirrors

Science.gov (United States)

Tracy, C. Edwin; Benson, David K.

1990-01-01

A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition thereon to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors. Also, the silver or other reflective metal layer on mirrors comprising thin, lightweight, flexible substrates of metal or polymer sheets coated with glassy layers can be protected with silicon nitride according to this invention.
[Mirror neurons].

Science.gov (United States)

Rubia Vila, Francisco José

2011-01-01

Mirror neurons were recently discovered in frontal brain areas of the monkey. They are activated when the animal makes a specific movement, but also when the animal observes the same movement in another animal. Some of them also respond to the emotional expression of other animals of the same species. These mirror neurons have also been found in humans. They respond to or "reflect" actions of other individuals in the brain and are thought to represent the basis for imitation and empathy and hence the neurobiological substrate for "theory of mind", the potential origin of language and the so-called moral instinct.
High-density plasma-induced etch damage of wafer-bonded AlGaInP/mirror/Si light-emitting diodes

CERN Document Server

Wuu, D S; Huang, S H; Chung, C R

2002-01-01

Dry etch of wafer-bonded AlGaInP/mirror/Si light-emitting diodes (LEDs) with planar electrodes was performed by high-density plasma using an inductively coupled plasma (ICP) etcher. The etching characteristics were investigated by varying process parameters such as Cl sub 2 /N sub 2 gas combination, chamber pressure, ICP power and substrate-bias power. The corresponding plasma properties (ion flux and dc bias), in situ measured by a Langmuir probe, show a strong relationship to the etch results. With a moderate etch rate of 1.3 mu m/min, a near vertical and smooth sidewall profile can be achieved under a Cl sub 2 /(Cl sub 2 +N sub 2) gas mixture of 0.5, ICP power of 800 W, substrate-bias power of 100 W, and chamber pressure of 0.67 Pa. Quantitative analysis of the plasma-induced damage was attempted to provide a means to study the mechanism of leakage current and brightness with various dc bias voltages (-110 to -328 V) and plasma duration (3-5 min) on the wafer-bonded LEDs. It is found that the reverse leaka...

A primary mirror metrology system for the GMT

Science.gov (United States)

Rakich, A.

2016-07-01

The Giant Magellan Telescope (GMT)1 is a 25 m "doubly segmented" telescope composed of seven 8.4 m "unit Gregorian telescopes", on a common mount. Each primary and secondary mirror segment will ideally lie on the geometrical surface of the corresponding rotationally symmetrical full aperture optical element. Therefore, each primary and conjugated secondary mirror segment will feed a common instrument interface, their focal planes co-aligned and cophased. First light with a subset of four unit telescopes is currently scheduled for 2022. The project is currently considering an important aspect of the assembly, integration and verification (AIV) phase of the project. This paper will discuss a dedicated system to directly characterize the on-sky performance of the M1 segments, independently of the M2 subsystem. A Primary Mirror Metrology System (PMS) is proposed. The main purpose of this system will be to he4lp determine the rotation axis of an instrument rotator (the Gregorian Instrument Rotator or GIR in this case) and then to characterize the deflections and deformations of the M1 segments with respect to this axis as a function of gravity and temperature. The metrology system will incorporate a small (180 mm diameter largest element) prime focus corrector (PFC) that simultaneously feeds a risk reduction during AIV; it allows an on-sky characterization of the primary mirror segments and cells, without the complications of other optical elements. The PMS enables a very useful alignment strategy that constrains each primary mirror segments' optical axes to follow the GIR axis to within a few arc seconds. An additional attractive feature of the incorporation of the PMS into the AIV plan, is that it allows first on-sky telescope operations to occur with a system of considerably less optical and control complexity than the final doubly segmented Gregorian telescope configuration. This paper first discusses the strategic rationale for a PMS. Next the system itself is
Characterization of a next-generation piezo bimorph X-ray mirror for synchrotron beamlines

Energy Technology Data Exchange (ETDEWEB)

Alcock, Simon G., E-mail: simon.alcock@diamond.ac.uk; Nistea, Ioana; Sutter, John P.; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Fermé, Jean-Jacques; Thellièr, Christophe; Peverini, Luca [Thales-SESO, 305 rue Louis Armand, Pôle d’Activités d’Aix les Milles, Aix-en-Provence (France)

2015-01-01

A next-generation bimorph mirror with piezos bonded to the side faces of a monolithic substrate was created. When replacing a first-generation bimorph mirror suffering from the junction effect, the new type of mirror significantly improved the size and shape of the reflected synchrotron X-ray beam. No evidence of the junction effect was observed even after eight months of continuous beamline usage. Piezo bimorph mirrors are versatile active optics used on many synchrotron beamlines. However, many bimorphs suffer from the ‘junction effect’: a periodic deformation of the optical surface which causes major aberrations to the reflected X-ray beam. This effect is linked to the construction of such mirrors, where piezo ceramics are glued directly below the thin optical substrate. In order to address this problem, a next-generation bimorph with piezos bonded to the side faces of a monolithic substrate was developed at Thales-SESO and optimized at Diamond Light Source. Using metrology feedback from the Diamond-NOM, the optical slope error was reduced to ∼0.5 µrad r.m.s. for a range of ellipses. To maximize usability, a novel holder was built to accommodate the substrate in any orientation. When replacing a first-generation bimorph on a synchrotron beamline, the new mirror significantly improved the size and shape of the reflected X-ray beam. Most importantly, there was no evidence of the junction effect even after eight months of continuous beamline usage. It is hoped that this new design will reinvigorate the use of active bimorph optics at synchrotron and free-electron laser facilities to manipulate and correct X-ray wavefronts.
Characterization of a next-generation piezo bimorph X-ray mirror for synchrotron beamlines

International Nuclear Information System (INIS)

Alcock, Simon G.; Nistea, Ioana; Sutter, John P.; Sawhney, Kawal; Fermé, Jean-Jacques; Thellièr, Christophe; Peverini, Luca

2015-01-01

A next-generation bimorph mirror with piezos bonded to the side faces of a monolithic substrate was created. When replacing a first-generation bimorph mirror suffering from the junction effect, the new type of mirror significantly improved the size and shape of the reflected synchrotron X-ray beam. No evidence of the junction effect was observed even after eight months of continuous beamline usage. Piezo bimorph mirrors are versatile active optics used on many synchrotron beamlines. However, many bimorphs suffer from the ‘junction effect’: a periodic deformation of the optical surface which causes major aberrations to the reflected X-ray beam. This effect is linked to the construction of such mirrors, where piezo ceramics are glued directly below the thin optical substrate. In order to address this problem, a next-generation bimorph with piezos bonded to the side faces of a monolithic substrate was developed at Thales-SESO and optimized at Diamond Light Source. Using metrology feedback from the Diamond-NOM, the optical slope error was reduced to ∼0.5 µrad r.m.s. for a range of ellipses. To maximize usability, a novel holder was built to accommodate the substrate in any orientation. When replacing a first-generation bimorph on a synchrotron beamline, the new mirror significantly improved the size and shape of the reflected X-ray beam. Most importantly, there was no evidence of the junction effect even after eight months of continuous beamline usage. It is hoped that this new design will reinvigorate the use of active bimorph optics at synchrotron and free-electron laser facilities to manipulate and correct X-ray wavefronts
Mirror Fusion Test Facility (MFTF)

International Nuclear Information System (INIS)

Thomassen, K.I.

1978-01-01

A large, new Mirror Fusion Test Facility is under construction at LLL. Begun in FY78 it will be completed at the end of FY78 at a cost of $94.2M. This facility gives the mirror program the flexibility to explore mirror confinement principles at a signficant scale and advances the technology of large reactor-like devices. The role of MFTF in the LLL program is described here
The mirror neuron system: new frontiers.

Science.gov (United States)

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into studying their location and properties in the human brain. Here we review these original findings and introduce the main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror system embedded into the mosaic of circuits that compose our brain? How does the mirror system contribute to communication, language and social interaction? Can the principle of mirror neurons be extended to emotions, sensations and thoughts? Papers using a wide range of methods, including single cell recordings, fMRI, TMS, EEG and psychophysics, collected in this special issue, start to give us some impressive answers.
Neoclassical resonant transport of a mirror cell

International Nuclear Information System (INIS)

Ito, T.; Katanuma, I.

2005-01-01

The neoclassical resonant plateau transport in a mirror cell is studied theoretically. The analytical expression for a non-square-well magnetic field is obtained. The analytical result is applied to the GAMMA10 tandem mirror [T. Cho, M. Yoshida, J. Kohagura et al., Phys. Rev. Lett. 94, 085002-1 (2005)], which consists of several mirror cells in it, and the confinement time due to the neoclassical resonant plateau transport is determined in each mirror cell. It is found that the neoclassical resonant transport of ions trapped in the nonaxisymmetric anchor mirror cell and transition mirror cells is significantly smaller than those trapped in the central cell
Evolution of the mirror machine

International Nuclear Information System (INIS)

Damm, C.C.

1983-01-01

The history of the magnetic-mirror approach to a fusion reactor is primarily the history of our understanding and control of several crucial physics issues, coupled with progress in the technology of heating and confining a reacting plasma. The basic requirement of an MHD-stable plasma equilibrium was achieved following the early introduction of minimum-B multipolar magnetic fields. In refined form, the same magnetic-well principle carries over to our present experiments and to reactor designs. The higher frequency microinstabilities, arising from the non-Maxwellian particle distributions inherent in mirror machines, have gradually come under control as theoretical prescriptions for distribution functions have been applied in the experiments. Even with stability, the classical plasma leakage through the mirrors posed a serious question for reactor viability until the principle of electrostatic axial stoppering was applied in the tandem mirror configuration. Experiments to test this principle successfully demonstrated the substantial improvement in confinement predicted. Concurrent with advances in mirror plasma physics, development of both high-power neutral beam injectors and high-speed vacuum pumping techniques has played a crucial role in ongoing experiments. Together with superconducting magnets, cryogenic pumping, and high-power radiofrequency heating, these technologies have evolved to a level that extrapolates readily to meet the requirements of a tandem mirror fusion reactor
Mirror neurons: functions, mechanisms and models.

Science.gov (United States)

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael A

2013-04-12

Mirror neurons for manipulation fire both when the animal manipulates an object in a specific way and when it sees another animal (or the experimenter) perform an action that is more or less similar. Such neurons were originally found in macaque monkeys, in the ventral premotor cortex, area F5 and later also in the inferior parietal lobule. Recent neuroimaging data indicate that the adult human brain is endowed with a "mirror neuron system," putatively containing mirror neurons and other neurons, for matching the observation and execution of actions. Mirror neurons may serve action recognition in monkeys as well as humans, whereas their putative role in imitation and language may be realized in human but not in monkey. This article shows the important role of computational models in providing sufficient and causal explanations for the observed phenomena involving mirror systems and the learning processes which form them, and underlines the need for additional circuitry to lift up the monkey mirror neuron circuit to sustain the posited cognitive functions attributed to the human mirror neuron system. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Plasma confinement apparatus using solenoidal and mirror coils

Science.gov (United States)

Fowler, T. Kenneth; Condit, William C.

1979-01-01

A plasma confinement apparatus, wherein multiple magnetic mirror cells are linked by magnetic field lines inside of a solenoid with the mirroring regions for adjacent magnetic mirror cells each formed by a separate mirror coil inside of the solenoid. The magnetic mirror cells may be field reversed.
Mirror neurons and language in schizophrenia

OpenAIRE

Bendová, Marie

2016-01-01

Mirror neurons are a specific kind of visuomotor neurons that are involved in action execution and also in action perception. The mirror mechanism is linked to a variety of complex psychological functions such as social-cognitive functions and language. People with schizophrenia have often difficulties both in mirror neuron system and in language skills. In the first part of our research we studied the connectivity of mirror neuron areas (such as IFG, STG, PMC, SMC and so on) by fMRI in resti...
5 V Compatible Two-Axis PZT Driven MEMS Scanning Mirror with Mechanical Leverage Structure for Miniature LiDAR Application.

Science.gov (United States)

Ye, Liangchen; Zhang, Gaofei; You, Zheng

2017-03-05

The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V. In this paper, we present an ultra-low voltage driven two-axis MEMS scanning mirror which is 5 V compatible. In order to realize low voltage and low power, a two-axis MEMS scanning mirror with mechanical leverage driven by PZT (Lead zirconate titanate) ceramic is designed, modeled, fabricated and characterized. To further decrease the power of the MEMS scanning mirror, a new method of impedance matching for PZT ceramic driven by a two-frequency mixed signal is established. As experimental results show, this MEMS scanning mirror reaches a two-axis scanning angle of 41.9° × 40.3° at a total driving voltage of 4.2 Vpp and total power of 16 mW. The effective diameter of reflection of the mirror is 2 mm and the operating frequencies of two-axis scanning are 947.51 Hz and 1464.66 Hz, respectively.
Plasma confinement apparatus using solenoidal and mirror coils

International Nuclear Information System (INIS)

Fowler, T.K.; Condit, W.C.

1979-01-01

A plasma confinement apparatus is described, wherein multiple magnetic mirror cells are linked by magnetic field lines inside of a solenoid with the mirroring regions for adjacent magnetic mirror cells each formed by a separate mirror coil inside of the solenoid. The magnetic mirror cells may be field reversed
Owning the body in the mirror: The effect of visual perspective and mirror view on the full-body illusion.

Science.gov (United States)

Preston, Catherine; Kuper-Smith, Benjamin J; Ehrsson, Henrik H

2015-12-17

Mirrors allow us to view our own body from a third-person (observer) perspective. However, how viewing ourselves through a mirror affects central body representations compared with true third-person perspective is not fully understood. Across a series of experiments, multisensory full-body illusions were used to modulate feelings of ownership over a mannequin body that was viewed from a third-person perspective through a mirror, from a third-person perspective without a mirror, and from a first-person perspective. In contrast to non-mirror third-person perspective, synchronously touching the participant's actual body and the mannequin body viewed in the mirror elicited strong feelings of ownership over the mannequin and increased physiological responses to the mannequin being threatened compared to the equivalent asynchronous (non-ownership) control condition. Subjective reports of ownership viewing the mannequin through a mirror were also statistically equivalent to those following the first-person perspective illusion. These findings suggest that mirrors have a special role for viewing the self. The results also support the importance of egocentric reference frames for body ownership and suggest that mirror reflections of one's own body are related to peripersonal space, which enables updating of central body representations.
Physics issues in mirror and tandem mirror systems

International Nuclear Information System (INIS)

Post, R.F.

1984-01-01

Over the years the study of the confinement of high temperature plasma in magnetic mirror systems has presented researchers with many unusual physics problems. Many of these issues are by now understood theoretically and documented experimentally. With the advent of the tandem mirror idea, some new issues have emerged and are now under intensive study. These include: (1) the generation and control of ambipolar confining potentials and their effect on axial confinement and, (2) the combined influence of nonaxisymmetric magnetic fields (used to ensure MHD stability) and electric magnetic particle drifts on radial transport. Physics considerations associated with these two categories of issues will be reviewed, including concepts for the control of radial transport, under study or proposed
The mirror neuron system : New frontiers

NARCIS (Netherlands)

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into Studying their location and properties in the human brain. Here we review these original findings and introduce the Main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror
A Hebbian learning rule gives rise to mirror neurons and links them to control theoretic inverse models

Directory of Open Access Journals (Sweden)

Alexander eHanuschkin

2013-06-01

Full Text Available Mirror neurons are neurons whose responses to the observation of a motor act resemble responses measured during production of that act. Computationally, mirror neurons have been viewed as evidence for the existence of internal inverse models. Such models, rooted within control theory, map desired sensory targets onto the motor commands required to generate those targets. To jointly explore both the formation of mirrored responses and their functional contribution to inverse models, we develop a correlation-based theory of interactions between a sensory and a motor area. We show that a simple eligibility-weighted Hebbian learning rule, operating within a sensorimotor loop during motor explorations and stabilized by heterosynaptic competition, naturally gives rise to mirror neurons as well as control theoretic inverse models encoded in the synaptic weights from sensory to motor neurons. Crucially, we find that the correlational structure or stereotypy of the neural code underlying motor explorations determines the nature of the learned inverse model: Random motor codes lead to causal inverses that map sensory activity patterns to their motor causes; such inverses are maximally useful, they allow for imitating arbitrary sensory target sequences. By contrast, stereotyped motor codes lead to less useful predictive inverses that map sensory activity to future motor actions.Our theory generalizes previous work on inverse models by showing that such models can be learned in a simple Hebbian framework without the need for error signals or backpropagation, and it makes new conceptual connections between the causal nature of inverse models, the statistical structure of motor variability, and the time-lag between sensory and motor responses of mirror neurons. Applied to bird song learning, our theory can account for puzzling aspects of the song system, including necessity of sensorimotor gating and selectivity of auditory responses to bird’s own song
A Hebbian learning rule gives rise to mirror neurons and links them to control theoretic inverse models.

Science.gov (United States)

Hanuschkin, A; Ganguli, S; Hahnloser, R H R

2013-01-01

Mirror neurons are neurons whose responses to the observation of a motor act resemble responses measured during production of that act. Computationally, mirror neurons have been viewed as evidence for the existence of internal inverse models. Such models, rooted within control theory, map-desired sensory targets onto the motor commands required to generate those targets. To jointly explore both the formation of mirrored responses and their functional contribution to inverse models, we develop a correlation-based theory of interactions between a sensory and a motor area. We show that a simple eligibility-weighted Hebbian learning rule, operating within a sensorimotor loop during motor explorations and stabilized by heterosynaptic competition, naturally gives rise to mirror neurons as well as control theoretic inverse models encoded in the synaptic weights from sensory to motor neurons. Crucially, we find that the correlational structure or stereotypy of the neural code underlying motor explorations determines the nature of the learned inverse model: random motor codes lead to causal inverses that map sensory activity patterns to their motor causes; such inverses are maximally useful, by allowing the imitation of arbitrary sensory target sequences. By contrast, stereotyped motor codes lead to less useful predictive inverses that map sensory activity to future motor actions. Our theory generalizes previous work on inverse models by showing that such models can be learned in a simple Hebbian framework without the need for error signals or backpropagation, and it makes new conceptual connections between the causal nature of inverse models, the statistical structure of motor variability, and the time-lag between sensory and motor responses of mirror neurons. Applied to bird song learning, our theory can account for puzzling aspects of the song system, including necessity of sensorimotor gating and selectivity of auditory responses to bird's own song (BOS) stimuli.
Mirror and grating surface figure requirements for grazing incidence synchrotron radiation beamlines: Power loading effects

Energy Technology Data Exchange (ETDEWEB)

Hulbert, S.L.; Sharma, S.

1987-01-01

At present, grazing incidence mirrors are used almost exclusively as the first optical element in VUV and soft x-ray synchrotron radiation beamlines. The performance of these mirrors is determined by thermal and mechanical stress-induced figure errors as well as by figure errors remaining from the grinding and polishing process. With the advent of VUV and soft x-ray undulators and wigglers has come a new set of thermal stress problems related to both the magnitude and the spatial distribution of power from these devices. In many cases the power load on the entrance slits and gratings in these beamlines is no longer negligible. The dependence of thermally-induced front-end mirror figure errors on various storage ring and insertion device parameters (especially those at the National Synchrotron Light Source) and the effects of these figure errors on two classes of soft x-ray beamlines are presented.
Spherical sila- and germa-homoaromaticity.

Science.gov (United States)

Chen, Zhongfang; Hirsch, Andreas; Nagase, Shigeru; Thiel, Walter; Schleyer, Paul von Ragué

2003-12-17

Guided by the 2(N + 1)2 electron-counting rule for spherical aromatic molecules, we have designed various spherical sila- and germa-homoaromatic systems rich in group 14 elements. Their aromaticity is revealed by density-functional computations of their structures and the nucleus-independent chemical shifts (NICS). Besides the formerly used endohedral inclusion strategy, spherical homoaromaticity is another way to stabilize silicon and germanium clusters.
The vertical-cavity surface-emitting laser incorporating a high contrast grating mirror as a sensing device

Science.gov (United States)

Marciniak, Magdalena; Gebski, Marcin; Piskorski, Łukasz; Dems, Maciej; Wasiak, M.; Panajotov, Krassimir; Lott, James A.; Czyszanowski, Tomasz

2018-02-01

We propose a novel optical sensing system based on one device that both emits and detects light consisting of a verticalcavity surface-emitting laser (VCSEL) incorporating an high contrast grating (HCG) as a top mirror. Since HCGs can be very sensitive to the optical properties of surrounding media, they can be used to detect gases and liquid. The presence of a gas or a liquid around an HCG mirror causes changes of the power reflectance of the mirror, which corresponds to changes of the VCSEL's cavity quality factor and current-voltage characteristic. By observation of the current-voltage characteristic we can collect information about the medium around the HCG. In this paper we investigate how the properties of the HCG mirror depend on the refractive index of the HCG surroundings. We present results of a computer simulation performed with a three-dimensional fully vectorial model. We consider silicon HCGs on silica and designed for a 1300 nm VCSEL emission wavelength. We demonstrate that our approach can be applied to other wavelengths and material systems.

Preliminary measurement performance evaluation of a new white light interferometer for cylindrical surfaces

International Nuclear Information System (INIS)

Albertazzi, Armando Jr; Pont, Alex Dal

2005-01-01

This paper introduces a new design of a white light interferometer, suitable for measurement of cylindrical or quasi-cylindrical parts. A high precision 45 deg. conical mirror is used to direct collimated light radially, making it possible to measure in true cylindrical coordinates. The image of the measurand, distorted by the conical mirror, is projected in a high resolution digital camera. A mapping algorithm is used to reconstruct the cylindrical geometry from the distorted image. The rest of the interferometer is quite similar to a conventional white light interferometer: A flat reference mirror is scanned through the measurement range while an algorithm is searching for the maximum contrast position of the interference pattern. The performance evaluation of a configuration suitable for measurement of external cylindrical surfaces is also presented in this paper. A master cylinder was used as reference. Uncertainties of about 1.0 μm were found at the present stage of development
Sensorimotor learning configures the human mirror system.

Science.gov (United States)

Catmur, Caroline; Walsh, Vincent; Heyes, Cecilia

2007-09-04

Cells in the "mirror system" fire not only when an individual performs an action but also when one observes the same action performed by another agent [1-4]. The mirror system, found in premotor and parietal cortices of human and monkey brains, is thought to provide the foundation for social understanding and to enable the development of theory of mind and language [5-9]. However, it is unclear how mirror neurons acquire their mirror properties -- how they derive the information necessary to match observed with executed actions [10]. We address this by showing that it is possible to manipulate the selectivity of the human mirror system, and thereby make it operate as a countermirror system, by giving participants training to perform one action while observing another. Before this training, participants showed event-related muscle-specific responses to transcranial magnetic stimulation over motor cortex during observation of little- and index-finger movements [11-13]. After training, this normal mirror effect was reversed. These results indicate that the mirror properties of the mirror system are neither wholly innate [14] nor fixed once acquired; instead they develop through sensorimotor learning [15, 16]. Our findings indicate that the human mirror system is, to some extent, both a product and a process of social interaction.
Mirror hybrid reactor blanket and power conversion system conceptual design

International Nuclear Information System (INIS)

Schultz, K.R.; Backus, G.A.; Baxi, C.B.; Dee, J.B.; Estrine, E.A.; Rao, R.; Veca, A.R.

1976-01-01

The conceptual design of the blanket and power conversion system for a gas-cooled mirror hybrid fusion-fission reactor is presented. The designs of the fuel, blanket module and power conversion system are based on existing gas-cooled fission reactor technology that has been developed at General Atomic Company. The uranium silicide fuel is contained in Inconel-clad rods and is cooled by helium gas. The fuel is contained in 16 spherical segment modules which surround the fusion plasma. The hot helium is used to raise steam for a conventional steam cycle turbine generator. The details of the method of support for the massive blanket modules and helium ducts remain to be determined. Nevertheless, the conceptual design appears to be technically feasible with existing gas-cooled technology. A preliminary safety analysis shows that with the development of a satisfactory method of primary coolant circuit containment and support, the hybrid reactor could be licensed under existing Nuclear Regulatory Commission regulations
Visual Detection and Tracking System for a Spherical Amphibious Robot.

Science.gov (United States)

Guo, Shuxiang; Pan, Shaowu; Shi, Liwei; Guo, Ping; He, Yanlin; Tang, Kun

2017-04-15

With the goal of supporting close-range observation tasks of a spherical amphibious robot, such as ecological observations and intelligent surveillance, a moving target detection and tracking system was designed and implemented in this study. Given the restrictions presented by the amphibious environment and the small-sized spherical amphibious robot, an industrial camera and vision algorithms using adaptive appearance models were adopted to construct the proposed system. To handle the problem of light scattering and absorption in the underwater environment, the multi-scale retinex with color restoration algorithm was used for image enhancement. Given the environmental disturbances in practical amphibious scenarios, the Gaussian mixture model was used to detect moving targets entering the field of view of the robot. A fast compressive tracker with a Kalman prediction mechanism was used to track the specified target. Considering the limited load space and the unique mechanical structure of the robot, the proposed vision system was fabricated with a low power system-on-chip using an asymmetric and heterogeneous computing architecture. Experimental results confirmed the validity and high efficiency of the proposed system. The design presented in this paper is able to meet future demands of spherical amphibious robots in biological monitoring and multi-robot cooperation.
Visual Detection and Tracking System for a Spherical Amphibious Robot

Science.gov (United States)

Guo, Shuxiang; Pan, Shaowu; Shi, Liwei; Guo, Ping; He, Yanlin; Tang, Kun

2017-01-01

With the goal of supporting close-range observation tasks of a spherical amphibious robot, such as ecological observations and intelligent surveillance, a moving target detection and tracking system was designed and implemented in this study. Given the restrictions presented by the amphibious environment and the small-sized spherical amphibious robot, an industrial camera and vision algorithms using adaptive appearance models were adopted to construct the proposed system. To handle the problem of light scattering and absorption in the underwater environment, the multi-scale retinex with color restoration algorithm was used for image enhancement. Given the environmental disturbances in practical amphibious scenarios, the Gaussian mixture model was used to detect moving targets entering the field of view of the robot. A fast compressive tracker with a Kalman prediction mechanism was used to track the specified target. Considering the limited load space and the unique mechanical structure of the robot, the proposed vision system was fabricated with a low power system-on-chip using an asymmetric and heterogeneous computing architecture. Experimental results confirmed the validity and high efficiency of the proposed system. The design presented in this paper is able to meet future demands of spherical amphibious robots in biological monitoring and multi-robot cooperation. PMID:28420134
Trieste lectures on mirror symmetry

Energy Technology Data Exchange (ETDEWEB)

Hori, K [Department of Physics and Department of Mathematics, University of Toronto, Toronto, Ontario (Canada)

2003-08-15

These are pedagogical lectures on mirror symmetry given at the Spring School in ICTP, Trieste, March 2002. The focus is placed on worldsheet descriptions of the physics related to mirror symmetry. We start with the introduction to general aspects of (2,2) supersymmetric field theories in 1 + 1 dimensions. We next move on to the study and applications of linear sigma model. Finally, we provide a proof of mirror symmetry in a class of models. (author)
A Research on the Primary Mirror Manipulator of Large Segmented-mirror Telescope

Science.gov (United States)

Zuo, H.

2012-09-01

Since Galileo firstly used the telescope to observe the sky 400 years ago, the aperture of the telescope has become larger and larger to observe the deeper universe, and the segmented-mirror telescope is becoming more and more popular with increasing aperture. In the early 21st century, a series of segmented-mirror telescopes have been constructed including the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) of China. LAMOST is a meridian reflecting Schmidt telescope, and the dimension of the primary mirror is about 6.7 m× 6 m, which is composed of 37 hexagonal sub-mirrors. However, a problem about the mirror installation appears with the increasing aperture. If there are hundreds of sub-mirrors in the telescope, it is a challenging job to mount and dismount them to the truss. This problem is discussed in this paper and a manipulator for the primary mirror of LAMOST is designed to perform the mount and dismount work. In chapter 1, all the segmented-mirror telescopes in the world are introduced and how the sub-mirrors of these telescopes are installed has been investigated. After comparing with the serial and the parallel robot, a serial robot manipulator proposal, which has several redundant degrees of freedom (DOFs), has been chosen from a series of design proposals. In chapter 2, the theoretical analysis has been carried out on the basis of the design proposal, which includes the forward kinematics and the inverse kinematics. Firstly the D-H coordinate is built according to the structure of the manipulator, so it is possible to obtain the end-effector position and orientation from the individual joint motion thanks to the forward kinematics. Because of the redundant DOFs of the manipulator, the inverse kinematics solution can be a very trick task, and the result may not be only, therefore a kind of simulation is carried out to get the numerical solution using ADAMS (Automatic Dynamic Analysis of Mechanical System). In the dynamics analysis the
PERFORMANCE EVALUATION OF A LIGHT-WEIGHT MULTI-ECHO LIDAR FOR UNMANNED ROTORCRAFT APPLICATIONS

Directory of Open Access Journals (Sweden)

G. Conte

2013-08-01

Full Text Available The paper presents a light-weight and low-cost airborne terrain mapping system. The developed Airborne LiDAR Scanner (ALS system consists of a high-precision GNSS receiver, an inertial measurement unit and a magnetic compass which are used to complement a LiDAR sensor in order to compute a digital surface model. Evaluation of the accuracy of the generated surface model is presented. Additionally, a comparison is provided between the surface model generated from the developed ALS system and a model generated using a commercial photogrammetric software. Finally, the multi-echo capability of the used LiDAR sensor is evaluated in areas covered with dense vegetation. The ALS system and camera systems were mounted on-board an industrial unmanned helicopter of around 100 kilograms maximum take-off weight. Presented results are based on real flight-test data.
Vertex algebras and mirror symmetry

International Nuclear Information System (INIS)

Borisov, L.A.

2001-01-01

Mirror Symmetry for Calabi-Yau hypersurfaces in toric varieties is by now well established. However, previous approaches to it did not uncover the underlying reason for mirror varieties to be mirror. We are able to calculate explicitly vertex algebras that correspond to holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in toric varieties. We establish the relation between these vertex algebras for mirror Calabi-Yau manifolds. This should eventually allow us to rewrite the whole story of toric mirror symmetry in the language of sheaves of vertex algebras. Our approach is purely algebraic and involves simple techniques from toric geometry and homological algebra, as well as some basic results of the theory of vertex algebras. Ideas of this paper may also be useful in other problems related to maps from curves to algebraic varieties.This paper could also be of interest to physicists, because it contains explicit description of holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in terms of free bosons and fermions. (orig.)
Top down viewing of the inductively coupled plasma using a dual grating, direct reading spectrograph and an all mirror optical system

International Nuclear Information System (INIS)

Apel, C.T.; Duchane, D.V.; Palmer, B.A.

1980-01-01

Using an all-mirror optical system, an inductively coupled plasma is viewed top down and the light is directed to a dual grating, direct reading spectrograph. Top down viewing of the plasma, with masking of the image of the argon plasma torus at the spectrograph entrance slit, significantly reduces background signal from the source and permits the use of the depth of field of the optical system to achieve compromise conditions for viewing the plasma. Light from the plasma source is introduced to the optical system by means of a mirror situated directly over the plasma. The system is exhausted in such a way that cool air flowing past the mirror forms a thermal barrier between the mirror and the plasma. Elements such as copper and lead have atomic and ionic lines which tend to exhibit self absorption when viewed top down through the cooler ground state atoms in the plume of the plasma. One of the approaches to this problem is to shear off the plume of the plasma with a jet of air directed across the tip of the plasma. A second approach is to make use of the dual grating, direct reading spectrograph and real-time computer system which easily permits the setting of alternate lines for each element so that self absorption and matrix effects are minimized. The design of the dual-grating, direct-reading spectrograph allows for the mounting of more than 200 13-mm-dia photomultiplier tubes along the focal curves. In an effort to demonstrate the use of fiber optics as a viable technique for the closer placement of exit slits, a red sensitive photomultiplier tube was coupled with a 30-cm fiber-optic ribbon to detect light from the Li 670.784 nm line on the focal curve. It was successful and had the added advantages of absorbing second-order ultraviolet light
Light weight radioisotope heater unit (LWRHU): a technical description of the reference design

International Nuclear Information System (INIS)

Tate, R.E.

1982-01-01

The Light Weight Radioisotope Heater Unit (LWRHU), a new radioisotope heater unit for use in space missions, is a 238 PuO 2 -fueled unit designed to provide a thermal watt in dispersed locations on a spacecraft. The LWRHU is required to maintain the temperature of a component at a level where the component will function reliably in space. Two major constraints are placed on the unit's design; it must be as light as possible and must provide enough protection to immobilize the plutonium fuel to the maximum extent in all phases of the unit's lifetime. The four components are pelletized fuel, platinum-alloy encapsulation, pyrolytic graphite thermal insulation, and high-technology graphite ablation shell. The LWRHU is a cylinder 32 mm (1.26 in.) high and 26 mm (1.02 in.) in diameter. It weighs slightly less than 40 g
Mirror reactor studies

International Nuclear Information System (INIS)

Moir, R.W.; Barr, W.L.; Bender, D.J.

1977-01-01

Design studies of a fusion mirror reactor, a fusion-fission mirror reactor, and two small mirror reactors are summarized. The fusion reactor uses 150-keV neutral-beam injectors based on the acceleration of negative ions. The injectors provide over 1 GW of continuous power at an efficiency greater than 80%. The fusion reactor has three-stage, modularized, Venetian blind, plasma direct converter with a predicted efficiency of 59% and a new concept for removal of the lune-shaped blanket: a crane is brought between the two halves of the Yin-Yang magnet, which are separated by a float. The design has desirable features such as steady-state operation, minimal impurity problems, and low first-wall thermal stress. The major disadvantage is low Q resulting in high re-circulating power and hence high cost of electrical power. However, the direct capital cost per unit of gross electrical power is reasonable [$1000/kW(e)]. By contrast, the fusion-fission reactor design is not penalized by re-circulating power and uses relatively near-term fusion technology being developed for the fusion power program. New results are presented on the Th- 233 U and the U- 239 Pu fuel cycles. The purpose of this hybrid is fuel production, with projected costs at $55/g of Pu or $127/g of 233 U. Blanket and cooling system designs, including an emergency cooling system, by General Atomic Company, lead us to the opinion that the reactor can meet expected safety standards for licensing. The smallest mirror reactor having only a shield between the plasma and the coil is the 4.2-m long fusion engineering research facility (FERF) designed for material irradiation. The smallest mirror reactor having both a blanket and shield is the 7.5-m long experimental power reactor (EPR), which has both a fusion and a fusion-fission version. (author)
Long, elliptically bent, active X-ray mirrors with slope errors <200 nrad.

Science.gov (United States)

Nistea, Ioana T; Alcock, Simon G; Kristiansen, Paw; Young, Adam

2017-05-01

Actively bent X-ray mirrors are important components of many synchrotron and X-ray free-electron laser beamlines. A high-quality optical surface and good bending performance are essential to ensure that the X-ray beam is accurately focused. Two elliptically bent X-ray mirror systems from FMB Oxford were characterized in the optical metrology laboratory at Diamond Light Source. A comparison of Diamond-NOM slope profilometry and finite-element analysis is presented to investigate how the 900 mm-long mirrors sag under gravity, and how this deformation can be adequately compensated using a single, spring-loaded compensator. It is shown that two independent mechanical actuators can accurately bend the trapezoidal substrates to a range of elliptical profiles. State-of-the-art residual slope errors of <200 nrad r.m.s. are achieved over the entire elliptical bending range. High levels of bending repeatability (ΔR/R = 0.085% and 0.156% r.m.s. for the two bending directions) and stability over 24 h (ΔR/R = 0.07% r.m.s.) provide reliable beamline performance.
EEG study of the mirror neuron system in children with high functioning autism.

Science.gov (United States)

Raymaekers, Ruth; Wiersema, Jan Roelf; Roeyers, Herbert

2009-12-22

Individuals with Autism Spectrum Disorder (ASD) are characterised by an impaired imitation, thought to be critical for early affective, social and communicative development. One neurological system proposed to underlie this function is the mirror neuron system (MNS) and previous research has suggested a dysfunctional MNS in ASD. The EEG mu frequency, more precisely the reduction of the mu power, is considered to be an index for mirror neuron functioning. In this work, EEG registrations are used to evaluate the mirror neuron functioning of twenty children with high functioning autism (HFA) between 8 and 13 years. Their mu suppression to self-executed and observed movement is compared to typically developing peers and related to age, intelligence and symptom severity. Both groups show significant mu suppression to both self and observed hand movements. No group differences are found in either condition. These results do not support the hypothesis that HFA is associated with a dysfunctional MNS. The discrepancy with previous research is discussed in light of the heterogeneity of the ASD population.
Mirroring of fibre ends for the LHCb SciFi project

CERN Document Server

Joram, Christian

2014-01-01

The relatively low light yields for tracks close to the midplane (y=0) of the SciFi tracker, in particular after radiation damage due to ionizing radiation, suggests to mirror the fibre ends. This note describes a set of tests and measurements in order to establish a viable mirror technology which combines high reflectivity with simplicity and low cost. The following technologies were evaluated: Aluminized Mylar film glued to the fibre ends, 3M Enhanced Specular Reflectance film glued to the fibre ends, Thin Film Aluminium vacuum coated on the fibre ends. The tests show that Aluminized Mylar film is a viable solution fulfilling all SciFi requirements. ESR film leads potentially to a higher reflectivity but its usability when glued to fibre ends could not (yet) be demonstrated. The Thin Film Aluminium coating disqualifies for reasons of cost and complexity without any performance gain. This report is meant as backup document for the LHCb SciFi TDR document to be submitted in February 2014.
Photocatalytic, antifogging mirror

International Nuclear Information System (INIS)

Takagi, K.; Makimoto, T.; Hiraiwa, H.; Negishi, T.

2001-01-01

This article is about the coating of thin titanium dioxide film by sputter deposition. When irradiated with solar light, thin titanium dioxide film exhibits high oxidizing power and provides sterilizing, cleaning, decomposing, and hydrophylic effects. This technique has already been used for coating building walls by the sol-gel method and by others and has been partly commercialized to make automotive sideview mirrors. There have been no practical applications of the sputter deposition method so far, but establishment of the coating method is expected because of its excellent properties of film production techniques such as film thickness uniformity, film quality durability, and freedom from environmental pollution. In this article we discuss the establishment of the method of evaluating the quality of thin titanium dioxide film, establishment of sputter-deposition conditions, and the results of observation by x-ray diffraction and atomic force microscopy of the thin film. It was found that titanium dioxide films, 200 nm or more in thickness, have the above mentioned performance and that sputter deposition allows the film to form without heating
Mirror Objects in the Solar System?

International Nuclear Information System (INIS)

Silagadze, Z.K.

2002-01-01

This talk was given at the Tunguska-2001 international conference but it is not about the Tunguska event. Instead we tried to give some flavor of mirror matter, which is predicted to exist if parity is an unbroken symmetry of nature, to non-experts. The possible connection of the mirror matter ideas to the Tunguska phenomenon was indicated by Foot and Gninenko some time ago and was elaborated by Foot in the separate talk at this conference. If the mirror world interpretation of the Tunguska like events is indeed correct then the most fascinating (but very speculative) possibility is that some well known celestial bodies with strange properties are in fact made mostly from mirror matter, and so maybe the mirror world was discovered long ago and we just have not suspected this. (author)
A comparison of performance of lightweight mirrors

Science.gov (United States)

Cho, Myung K.; Richard, Ralph M.; Hileman, Edward A.

1990-01-01

Four lightweight solid contoured back mirror shapes (a double arch, a single arch, a modified single arch, and a double concave mirror) and a cellular sandwich lightweight meniscus mirror, have been considered for the primary mirror of the Space Infrared Telescope Facility (SIRTF). A parametric design study using these shapes for the SIRTF 40 inch primary mirror with a focal ratio f/2 is presented. Evaluations of the optical performance and fundamental frequency analyses are performed to compare relative merits of each mirror configuration. Included in these are structural, optical, and frequency analyses for (1) different back contour shapes, (2) different number and location of the support points, and (3) two gravity orientations (ZENITH and HORIZON positions). The finite element program NASTRAN is used to obtain the structural deflections of the optical surface. For wavefront error analysis, FRINGE and PCFRINGE programs are used to evaluate the optical performance. A scaling law relating the optical and structural performance for various mirror contoured back shapes is developed.
Phase-stepping optical profilometry of atom mirrors

International Nuclear Information System (INIS)

MacLaren, D A; Goldrein, H T; Holst, B; Allison, W

2003-01-01

Electrically deformed single crystal mirrors will be a vital part of a first generation of scanning helium microscope (SHeM). Optimized mirrors will be used to focus thermal energy helium atoms into a surface-sensitive, low-energy probe, with a resolution that depends upon the precise mirror shape. Here, we present surface profilometry measurements of a prototype atom mirror. A temporal phase-stepping Mach-Zender fibre interferometer is used to profile the mirror surface with an accuracy of a few tens of nanometres. Results are compared with the theory of small deflections of an elastic thin plate. Our experiments suggest that relatively simple apparatus can induce the mirror profiles required to demagnify a conventional helium source into a microprobe suitable for a SHeM. Use of elliptical boundary conditions in the clamping mechanism afford biaxial bending in the crystal whilst a simple double-electrode design is demonstrated to be capable of asymmetric control of the mirror deformation
Tandem mirror next step conceptual design

International Nuclear Information System (INIS)

Doggett, J.N.; Damm, C.C.; Bulmer, R.H.

1980-01-01

A study was made to define the features of the experimental mirror fusion device - The Tandem Mirror Next Step, or TMNS - that will bridge the gap between present mirror confinement experiments and a power-producing reactor. We outline the project goals, describe some initial device parameters, and relate the technological requirements to ongoing development programs

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