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Sample records for acoustic lens design

  1. Multi-acoustic lens design methodology for a low cost C-scan photoacoustic imaging camera

    Chinni, Bhargava; Han, Zichao; Brown, Nicholas; Vallejo, Pedro; Jacobs, Tess; Knox, Wayne; Dogra, Vikram; Rao, Navalgund

    2016-03-01

    We have designed and implemented a novel acoustic lens based focusing technology into a prototype photoacoustic imaging camera. All photoacoustically generated waves from laser exposed absorbers within a small volume get focused simultaneously by the lens onto an image plane. We use a multi-element ultrasound transducer array to capture the focused photoacoustic signals. Acoustic lens eliminates the need for expensive data acquisition hardware systems, is faster compared to electronic focusing and enables real-time image reconstruction. Using this photoacoustic imaging camera, we have imaged more than 150 several centimeter size ex-vivo human prostate, kidney and thyroid specimens with a millimeter resolution for cancer detection. In this paper, we share our lens design strategy and how we evaluate the resulting quality metrics (on and off axis point spread function, depth of field and modulation transfer function) through simulation. An advanced toolbox in MATLAB was adapted and used for simulating a two-dimensional gridded model that incorporates realistic photoacoustic signal generation and acoustic wave propagation through the lens with medium properties defined on each grid point. Two dimensional point spread functions have been generated and compared with experiments to demonstrate the utility of our design strategy. Finally we present results from work in progress on the use of two lens system aimed at further improving some of the quality metrics of our system.

  2. Flat acoustic lens by acoustic grating with curled slits

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry–Perot resonance. - Highlights: • Expression of transmission coefficient of an acoustic grating with curled slits. • Non-dispersive and tunable effective medium parameters for the acoustic grating. • A flat acoustic focusing lens with gradient index by using the acoustic grating

  3. Study of focusing characteristics of ultrasound for designing acoustic lens in ultrasonic moxibustion device

    Bae, Jae Hyun; Song, Sung Jin; Kim, Hak Joon [School of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Kim, Ki Bok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2015-04-15

    Traditional moxibustion therapy can cause severe pain and leave scarring burns at the moxibustion site as it relies on the practitioner's subjective and qualitative treatment. Recently, ultrasound therapy has received attention as an alternative to moxibustion therapy owing to its objectiveness and quantitative nature. However, in order to convert ultrasound energy into heat energy, there is a need to precisely understand the ultrasound-focusing characteristics of the acoustic lens. Therefore, in this study, an FEM simulation was performed for acoustic lenses with different geometries a concave lens and zone lens as the geometry critically influences ultrasound focusing. The acoustic pressure field, amplitude, and focal point were also calculated. Furthermore, the performance of the fabricated acoustic lens was verified by a sound pressure measurement experiment.

  4. Flat acoustic lens by acoustic grating with curled slits

    Peng, Pai

    2014-10-01

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance.

  5. Acoustic lens for capacitive micromachined ultrasonic transducers

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing. (paper)

  6. A passively tunable acoustic metamaterial lens for selective ultrasonic excitation

    In this paper, we present an approach to ultrasonic beam-forming and beam-steering in structures based on the concept of embedded acoustic metamaterial lenses. The lens design exploits the principle of acoustic drop-channel that enables the dynamic coupling of multiple ultrasonic waveguides at selected frequencies. In contrast with currently available technology, the embedded lens allows exploiting the host structure as a key component of the transducer system therefore enabling directional excitation by means of a single ultrasonic transducer. The design and the performance of the lens are numerically investigated by using Plane Wave Expansion and Finite Difference Time Domain techniques applied to bulk structures. Then, the design is experimentally validated on a thin aluminum plate waveguide where the lens is implemented by through-holes. The dynamic response of the embedded lens is estimated by reconstructing, via Laser Vibrometry, the velocity field induced by a single source located at the center of the lens

  7. A course in lens design

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  8. A passively tunable non-resonant acoustic metamaterial lens for selective ultrasonic excitation

    Zhu, Hongfei

    2014-01-01

    In this paper, we present an approach to ultrasonic beam-forming and beam-steering in structures based on the concept of embedded non-resonant acoustic metamaterial lenses. The lens design exploits the principle of acoustic drop-channel which enables the dynamic coupling of multiple ultrasonic waveguides at selected frequencies. In contrast with currently available technology, the embedded lens allows generating directional excitation by means of a single ultrasonic transducer. The lens design and performance are numerically investigated by using Plane Wave Expansion and Finite Difference Time Domain techniques applied to bulk structures. Then, the design is experimentally validated on a thin aluminum plate where the lens is implemented by through-holes. The dynamic response of the embedded lens is estimated by reconstructing, via Laser Vibrometry, the velocity field induced by a piezoelectric shaker source.

  9. Inverse Design of Electron Lens

    2001-01-01

    The inverae design of electron lens is reelized by two different methods in this paper. One isdamped leastsquare method and the other is the artificial neural network method. Their merits and defects are discussed accordingto our calculation results in the psper. In the condition of selecting the learning samples properly, the artificial neuralnetwork has obvious advantages in the inverse design of electron lens. It is an effective method to solve the inversedesign problem in the electron optic system.

  10. Small-Scale Trial for Evaluating Directional Resolution of Single Spherical Biconcave Acoustic Lens in Designing of Ambient Noise Imaging System

    Mori, Kazuyoshi; Ogasawara, Hanako; Nakamura, Toshiaki

    2008-05-01

    Ambient noise imaging (ANI) is the revolutionary idea of detecting objects by using natural ocean background noise. From the analysis results obtained by the finite difference time domain (FDTD) method in our previous studies, it was supposed that a spherical biconcave lens with an aperture diameter of 2.0 m has a sufficient directional resolution (for example, the beam width is 1° at 60 kHz) for realizing an ANI system. In this study, to confirm the analysis results, we performed a small-scale trial of one-fifth space in a water tank. The lens, made of acrylic resin, has an aperture diameter of 400 mm and a radius of curvature of 500 mm. A burst pulse of 25 cycles at 300 kHz, whose frequency increases 5 times, was radiated from the sound source. The sound pressure after passage through the acoustic lens was measured by moving the receiver around the image point. Results show that the shapes of -3 dB areas are similar to the FDTD analysis results at small incidence angles. It was verified that this lens has a sufficient directional resolution for use in the ANI system, because -3 dB areas do not overlap each other.

  11. High frequency acoustic microscopy with Fresnel zoom lens

    2007-01-01

    The acoustic field distributions and the convergent beams generated by the planar-structure Fresnel zone transducers on solid surface are investigated. Because only 0 and 180 degree phase transducers are used, an imaging system with the Fresnel zoom lens could work at very high frequency, which overcomes the frequency limit of the traditional phased array acoustic imaging system. Simulation results are given to illustrate the acoustic field distributions along the focal axis and the whole plane as well. Based on the principle of scanning of the focus with the change of frequency for the excited signal, an experimental imaging system is also built. Acoustic Fresnel zone transducers are fabricated at center frequency of 400 MHz. Measurements and detections of the known hole flaws at different depths of the fused quartz sample are presented to show that the imaging system with Fresnel zoom lens could move its focus by only changing the frequency of the excited signal.

  12. Acoustic Properties of Lens Materials for Ultrasonic Probes

    Fujii, Hideji; Nakaya, Chitose; Takeuchi, Hiroshi; Kondo, Toshio; Ishikawa, Yasuo

    1995-01-01

    The acoustic velocities and densities of 20 types of commercial rubber have been measured at a frequency of 2 MHz at room temperature, and they are evaluated in terms of their application to an acoustic lens or an acoustic window of probes of an ultrasonic diagnostic instrument. Fluorosilicone rubber and phoshazene rubber have lower acoustic velocities than the human body, and they have excellent impedance matching with the human body. Both the acoustic velocities and densities of butadiene rubber, polybutadiene rubber, acrylic rubber and polyurethane match those of the human body. It is also described that rubber having good impedance matching with the human body can be fabricated by adjusting the volume fraction of the added filler.

  13. Acoustic metamaterial design and applications

    Zhang, Shu

    The explosion of interest in metamaterials is due to the dramatically increased manipulation ability over light as well as sound waves. This material research was stimulated by the opportunity to develop an artificial media with negative refractive index and the application in superlens which allows super-resolution imaging. High-resolution acoustic imaging techniques are the essential tools for nondestructive testing and medical screening. However, the spatial resolution of the conventional acoustic imaging methods is restricted by the incident wavelength of ultrasound. This is due to the quickly fading evanescent fields which carry the subwavelength features of objects. By focusing the propagating wave and recovering the evanescent field, a flat lens with negative-index can potentially overcome the diffraction limit. We present the first experimental demonstration of focusing ultrasound waves through a flat acoustic metamaterial lens composed of a planar network of subwavelength Helmholtz resonators. We observed a tight focus of half-wavelength in width at 60.5 KHz by imaging a point source. This result is in excellent agreement with the numerical simulation by transmission line model in which we derived the effective mass density and compressibility. This metamaterial lens also displays variable focal length at different frequencies. Our experiment shows the promise of designing compact and light-weight ultrasound imaging elements. Moreover, the concept of metamaterial extends far beyond negative refraction, rather giving enormous choice of material parameters for different applications. One of the most interesting examples these years is the invisible cloak. Such a device is proposed to render the hidden object undetectable under the flow of light or sound, by guiding and controlling the wave path through an engineered space surrounding the object. However, the cloak designed by transformation optics usually calls for a highly anisotropic metamaterial, which

  14. Theoretical analysis of leaky surface acoustic waves of point-focused acoustic lens and some experiments

    When a point-focused acoustic lens in the scanning acoustic microscope (SAM) is faced to test specimen and defocused to some extent, two effective echoes can be obtained. One is the echo of longitudinal wave, which is normally incident upon the specimen of an on-axis beam in the central region of the lens and is reflected normal to the lens surface, hence detected by the transducer. The other is of leaky surface acoustic waves(LSAW), which are mode converted front a narrow beam of off-axis longitudinal wave, then propagate across the surface of the specimen and reradiate at angles normal to the lens surface, thus detected by the transducer. These two echoes are either interfered or separated with each other depending ell the defocused distance. It turned out theoretically that the LSAW have a narrow focal spot in the central region of the point-focused acoustic lens, whose size is approximately 40% of the LSAW wavelength. On top of that, a wavelength of LSAW is about 50% short as that of longitudinal wave. So, It is expected that high resolution images can be obtained provided LSAW are used in the scanning acoustic microscope.

  15. Design and Experimental Applications of Acoustic Metamaterials

    Zigoneanu, Lucian

    Acoustic metamaterials are engineered materials that were extensively investigated over the last years mainly because they promise properties otherwise hard or impossible to find in nature. Consequently, they open the door for improved or completely new applications (e.g. acoustic superlens that can exceed the diffraction limit in imaging or acoustic absorbing panels with higher transmission loss and smaller thickness than regular absorbers). Our objective is to surpass the limited frequency operating range imposed by the resonant mechanism that s1ome of these materials have. In addition, we want acoustic metamaterials that could be experimentally demonstrated and used to build devices with overall performances better than the previous ones reported in the literature. Here, we start by focusing on the need of engineered metamaterials in general and acoustic metamaterials in particular. Also, the similarities between electromagnetic metamaterials and acoustic metamaterials and possible ways to realize broadband acoustic metamaterials are briefly discussed. Then, we present the experimental realization and characterization of a two-dimensional (2D) broadband acoustic metamaterial with strongly anisotropic effective mass density. We use this metamaterial to realize a 2D broadband gradient index acoustic lens in air. Furthermore, we optimize the lens design by improving each unit cell's performance and we also realize a 2D acoustic ground cloak in air. In addition, we explore the performance of some novel applications (a 2D acoustic black hole and a three-dimensional acoustic cloak) using the currently available acoustic metamaterials. In order to overcome the limitations of our designs, we approach the active acoustic metamaterials path, which offers a broader range for the material parameters values and a better control over them. We propose two structures which contain a sensing element (microphone) and an acoustic driver (piezoelectric membrane or speaker). The

  16. Lens design based on lens form parameters using Gaussian brackets

    Yuan, Xiangyu; Cheng, Xuemin

    2014-11-01

    The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.

  17. Acoustic Eaton lens array and its fluid application

    Kim, Sang-Hoon; Das, Mukunda P

    2016-01-01

    A principle of an acoustic Eaton Lens array and its application as a removable tsunami wall is proposed theoretically. The lenses are made of expandable rubber balloons and create a stop-band by the rotating the incoming tsunami wave and reduce the pressure by canceling each other. The diameter of each lens is larger than the wavelength of the tsunami near the coast, that is, order of a kilometer. The impedance matching on the border of the lenses results in little reflection. Before a tsunami, the balloons are buried underground in shallow water near the coast in folded or rounded form. Upon sounding of the tsunami alarm, water and air are pumped into the balloons, which expand and erect the wall above the sea level within a few hours. After the tsunami, the water and air are released from the balloons, which are then buried underground for reuse. Electricity is used to power the entire process.

  18. Negative refraction imaging of acoustic metamaterial lens in the supersonic range

    Jianning Han; Tingdun Wen; Peng Yang; Lu Zhang

    2014-01-01

    Acoustic metamaterials with negative refraction index is the most promising method to overcome the diffraction limit of acoustic imaging to achieve ultrahigh resolution. In this paper, we use localized resonant phononic crystal as the unit cell to construct the acoustic negative refraction lens. Based on the vibration model of the phononic crystal, negative quality parameters of the lens are obtained while excited near the system resonance frequency. Simulation results show that negative refr...

  19. Tunable optical lens array using viscoelastic material and acoustic radiation force

    Koyama, Daisuke, E-mail: dkoyama@mail.doshisha.ac.jp; Kashihara, Yuta; Matsukawa, Mami [Faculty of Science and Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Hatanaka, Megumi [Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe 610-0321 (Japan); Nakamura, Kentaro [Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259-R2-26, Nagatsutacho, Midoriku, Yokohama 226-8503 (Japan)

    2015-10-28

    A movable optical lens array that uses acoustic radiation force was investigated. The lens array consists of a glass plate, two piezoelectric bimorph transducers, and a transparent viscoelastic gel film. A cylindrical lens array with a lens pitch of 4.6 mm was fabricated using the acoustic radiation force generated by the flexural vibration of the glass plate. The focal point and the positioning of the lenses can be changed using the input voltage and the driving phase difference between the two transducers, respectively.

  20. Tunable optical lens array using viscoelastic material and acoustic radiation force

    A movable optical lens array that uses acoustic radiation force was investigated. The lens array consists of a glass plate, two piezoelectric bimorph transducers, and a transparent viscoelastic gel film. A cylindrical lens array with a lens pitch of 4.6 mm was fabricated using the acoustic radiation force generated by the flexural vibration of the glass plate. The focal point and the positioning of the lenses can be changed using the input voltage and the driving phase difference between the two transducers, respectively

  1. An inverse and analytic lens design method

    Lu, Yang

    2016-01-01

    Traditional lens design is a numerical and forward process based on ray tracing and aberration theory. This method has limitations because the initial configuration of the lens has to be specified and the aberrations of the lenses have to considered. This paper is an initial attempt to investigate an analytic and inverse lens design method, called Lagrange, to overcome these barriers. Lagrange method tries to build differential equations in terms of the system parameters and the system input and output (object and image). The generalized Snell's law in three dimensional space and the normal of a surface in fundamental differential geometry are applied. Based on the Lagrange method equations for a single surface system are derived which can perfectly image a point object.

  2. A high transmission broadband gradient index lens using elastic shell acoustic metamaterial elements

    Titovich, Alexey S.; Haberman, Michael R.; Norris, Andrew N.

    2016-01-01

    The use of cylindrical elastic shells as elements in acoustic metamaterial devices is demonstrated through simulations and underwater measurements of a cylindrical-to-plane wave lens. Transformation acoustics (TA) of a circular region to a square dictates that the effective density in the lens remain constant and equal to that of water. Piecewise approximation to the desired effective compressibility is achieved using a square array with elements based on the elastic shell metamaterial concep...

  3. Negative refraction imaging of acoustic metamaterial lens in the supersonic range

    Acoustic metamaterials with negative refraction index is the most promising method to overcome the diffraction limit of acoustic imaging to achieve ultrahigh resolution. In this paper, we use localized resonant phononic crystal as the unit cell to construct the acoustic negative refraction lens. Based on the vibration model of the phononic crystal, negative quality parameters of the lens are obtained while excited near the system resonance frequency. Simulation results show that negative refraction of the acoustic lens can be achieved when a sound wave transmiting through the phononic crystal plate. The patterns of the imaging field agree well with that of the incident wave, while the dispersion is very weak. The unit cell size in the simulation is 0.0005 m and the wavelength of the sound source is 0.02 m, from which we show that acoustic signal can be manipulated through structures with dimensions much smaller than the wavelength of incident wave

  4. Negative refraction imaging of acoustic metamaterial lens in the supersonic range

    Jianning Han

    2014-05-01

    Full Text Available Acoustic metamaterials with negative refraction index is the most promising method to overcome the diffraction limit of acoustic imaging to achieve ultrahigh resolution. In this paper, we use localized resonant phononic crystal as the unit cell to construct the acoustic negative refraction lens. Based on the vibration model of the phononic crystal, negative quality parameters of the lens are obtained while excited near the system resonance frequency. Simulation results show that negative refraction of the acoustic lens can be achieved when a sound wave transmiting through the phononic crystal plate. The patterns of the imaging field agree well with that of the incident wave, while the dispersion is very weak. The unit cell size in the simulation is 0.0005 m and the wavelength of the sound source is 0.02 m, from which we show that acoustic signal can be manipulated through structures with dimensions much smaller than the wavelength of incident wave.

  5. Negative refraction imaging of acoustic metamaterial lens in the supersonic range

    Han, Jianning [School of Information and Communication Engineering, North University of China, Taiyuan 030051 (China); Wen, Tingdun [Key Laboratory of Instrumental Science and Dynamic Testing, Ministry of Education, North University of China, Taiyuan 030051 (China); Key Laboratory of Electronic Testing Technology, North University of China, Taiyuan 030051 (China); Yang, Peng; Zhang, Lu [Key Laboratory of Electronic Testing Technology, North University of China, Taiyuan 030051 (China)

    2014-05-15

    Acoustic metamaterials with negative refraction index is the most promising method to overcome the diffraction limit of acoustic imaging to achieve ultrahigh resolution. In this paper, we use localized resonant phononic crystal as the unit cell to construct the acoustic negative refraction lens. Based on the vibration model of the phononic crystal, negative quality parameters of the lens are obtained while excited near the system resonance frequency. Simulation results show that negative refraction of the acoustic lens can be achieved when a sound wave transmiting through the phononic crystal plate. The patterns of the imaging field agree well with that of the incident wave, while the dispersion is very weak. The unit cell size in the simulation is 0.0005 m and the wavelength of the sound source is 0.02 m, from which we show that acoustic signal can be manipulated through structures with dimensions much smaller than the wavelength of incident wave.

  6. Zoom lens design for tilted objects

    Malone, Robert M.; Frayer, Daniel K.; Kaufman, Morris I.; Leffler, Heather R.; McGillivray, Kevin D.; Meidinger, Alfred; Phillips, David H.

    2015-09-01

    When a zoom lens views a tilted finite conjugate object, its image plane is both tilted and distorted depending on magnification. Our camera image plane moves with six degrees of freedom; only one moving doublet lens is required to change magnification. Two lens design models were analyzed. The first required the optical and mechanical axes to be collinear, resulting in a tilted stop. The second allowed the optical axis to be tilted from the lens mechanical axis with an untilted stop moving along the mechanical axis. Both designs produced useful zoom lenses with excellent resolution for a distorted image. For both lens designs, the stop is anchored to the moving doublet and its diameter is unchanged throughout magnification changes. This unusual outcome allows the light level at each camera pixel to remain constant, independent of magnification. As-built tolerance analysis is used to compare both optical models. The design application is for proton radiography. At the end of an accelerator, protons exit an aluminum vacuum window producing a shadowgraph image onto an LYSO (lutetium yttrium orthosilicate) scintillator. The 5″ square scintillator emission reflects off a pellicle and is collected by the zoom lenses located 24″ away. Four zoom lenses will view the same pellicle at different alpha and beta angles. Blue emission from the scintillator is viewed at an alpha angle of -14° or -23° and beta angles of ±9° or ±25°. The pellicle directs the light backwards to a zone where adequate shielding of the cameras can be achieved against radiation scattered from the aluminum window.

  7. Design of acoustic devices by topology optimization

    Sigmund, Ole; Jensen, Jakob Søndergaard

    The goal of this study is to design and optimize structures and devices that are subjected to acoustic waves. Examples are acoustic lenses, sound walls, waveguides and loud speakers. We formulate the design problem as a topology optimization problem, i.e. distribute material in a design domain such...... that the acoustic response is optimized....

  8. The design and fabrication of common optical components lithography lens

    Huang, Jiun-Woei

    2015-07-01

    The design and fabrication of common optical components lithography Lens has been carried out for a 1 to 1 stepper. The specification of lens is fulfilled the 3-D lithography system as 2 micron in resolution for 1 inch x 2.8 inches system. The lens has been sophistically designed by dual path in a triplet to reduce the number of components. A single aspherical surface has been applied to reduce the aberration to diffraction limit in lens. The well-made shapes of lens have been suggested. Then, the fabrication of lens has been in the process. Finally, the optical axis of tolerance optical mechanical mountings for lens system in assembly has been analyzed, and valuable for assembly and fabrication.

  9. A high transmission broadband gradient index lens using elastic shell acoustic metamaterial elements

    Titovich, Alexey S; Norris, Andrew N

    2016-01-01

    The use of cylindrical elastic shells as elements in acoustic metamaterial devices is demonstrated through simulations and underwater measurements of a cylindrical-to-plane wave lens. Transformation acoustics (TA) of a circular region to a square dictates that the effective density in the lens remain constant and equal to that of water. Piecewise approximation to the desired effective compressibility is achieved using a square array with elements based on the elastic shell metamaterial concept developed in [30]. The size of the elements are chosen based on availability of shells, minimizing fabrication difficulties. The tested device is neutrally buoyant comprising 48 elements of nine different types of commercial shells made from aluminum, brass, copper, and polymers. Simulations indicate a broadband range in which the device acts as a cylindrical to plane wave lens. The experimental findings confirm the broadband quadropolar response from approximately 20 to 40 kHz, with positive gain of the radiation patte...

  10. Design of embedded acoustic lenses in plate-like structures based on periodic acoustic black holes

    Zhu, Hongfei; Semperlotti, Fabio

    2015-03-01

    We use a recently developed class of metamaterials based on geometric inhomogeneities to design acoustic lenses embedded in thin-walled structural element. The geometric inhomogeneity is based on the concept of Acoustic Black Hole (ABH) that is an exponential taper fully integrated in the supporting structure. The ABH is an element able to bend and, eventually, trap acoustic waves by creating areas with carefully engineered phase velocity gradients. Periodic lattices of ABHs are first studied in terms of their dispersion characteristics and then embedded in thin-plate structures to create lenses for ultrasonic focusing and collimation. Numerical simulations show the ability of the ABH lens to create focusing and collimation effects in an extended operating range that goes from the metamaterial to the phononic regime.

  11. A collimated focused ultrasound beam of high acoustic transmission and minimum diffraction achieved by using a lens with subwavelength structures

    Lin, Zhou; Tu, Juan; Cheng, Jianchun [Key Laboratory of Modern Acoustics (MOE), Department of Physics, Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing 210093 (China); Guo, Xiasheng, E-mail: guoxs@nju.edu.cn, E-mail: dzhang@nju.edu.cn [Key Laboratory of Modern Acoustics (MOE), Department of Physics, Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing 210093 (China); Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Wu, Junru [Department of Physics, University of Vermont, Burlington, Vermont 05405 (United States); Huang, Pingtong [Department of Ultrasound, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009 (China); Zhang, Dong, E-mail: guoxs@nju.edu.cn, E-mail: dzhang@nju.edu.cn [Key Laboratory of Modern Acoustics (MOE), Department of Physics, Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing 210093 (China); The State Key Laboratory of Acoustics, Chinese Academy of Science, Beijing 10080 (China)

    2015-09-14

    An acoustic focusing lens incorporated with periodically aligned subwavelength grooves corrugated on its spherical surface has been developed. It is demonstrated theoretically and experimentally that acoustic focusing achieved by using the lens can suppress the relative side-lobe amplitudes, enhance the focal gain, and minimize the shifting of the focus. Use of the lens coupled with a planar ultrasound transducer can generate an ultrasound beam with enhanced acoustic transmission and collimation effect, which offers the capability of improving the safety, efficiency, and accuracy of targeted surgery implemented by high intensity focused ultrasound.

  12. A collimated focused ultrasound beam of high acoustic transmission and minimum diffraction achieved by using a lens with subwavelength structures

    An acoustic focusing lens incorporated with periodically aligned subwavelength grooves corrugated on its spherical surface has been developed. It is demonstrated theoretically and experimentally that acoustic focusing achieved by using the lens can suppress the relative side-lobe amplitudes, enhance the focal gain, and minimize the shifting of the focus. Use of the lens coupled with a planar ultrasound transducer can generate an ultrasound beam with enhanced acoustic transmission and collimation effect, which offers the capability of improving the safety, efficiency, and accuracy of targeted surgery implemented by high intensity focused ultrasound

  13. Numerical Simulation of Target Range Estimation Using Ambient Noise Imaging with Acoustic Lens

    Mori, Kazuyoshi; Ogasawara, Hanako; Nakamura, Toshiaki; Tsuchiya, Takenobu; Endoh, Nobuyuki

    2010-07-01

    In ambient noise imaging (ANI), each pixel of a target image is mapped by either monochrome or pseudo color to represent its acoustic intensity in each direction. This intensity is obtained by measuring the target object's reflecting or scattering wave, with ocean background noise serving as the sound source. In the case of using an acoustic lens, the ANI system creates a C-mode-like image, where receivers are arranged on a focal plane and each pixel's color corresponds to the intensity of each receiver output. There is no consideration for estimating a target range by this method, because it is impossible to measure the traveling time between a transducer and a target by a method like an active imaging sonar. In this study, we tried to estimate a target range using the ANI system with an acoustic lens. Here, we conducted a numerical simulation of sound propagation based on the principle of the time reversal mirror. First, instead of actual ocean measurements in the forward propagation, we calculated the scattering wave from a rigid target object in an acoustic noise field generated by a large number of point sources using the two-dimensional (2D) finite difference time domain (FDTD) method. The time series of the scattering wave converged by the lens was then recorded on each receiver. The sound pressure distribution assuming that the time-reversed wave of the scattering wave was reradiated from each receiver position was also calculated using the 2D FDTD method in the backward propagation. It was possible to estimate a target range using the ANI system with an acoustic lens, because the maximum position of the reradiated sound pressure field was close to the target position.

  14. Accelerating convergence in automatic lens design

    Among the various factors that slow lens optimization-insufficient performance targets, the absence of a unique solution, false local minima, a poorly scaled change vector, failure to find the optimum damping number, and failure to equalize the parameter gradients-the importance of parameter gradient equalization has been insufficiently recognized. Gradients can be approximately equalized by scaling the lens to a suitable size while it is being optimized. For best results, the size of the damping number should also be optimized during each iteration. If these two procedures are followed, scaling the change vector is usually not crucial. To illustrate the importance of parameter equalization, a lens optimization is analyzed

  15. Worship space acoustics 3 decades of design

    Ryherd, Erica; Ronsse, Lauren

    2016-01-01

    This book takes the reader on a wide-ranging tour through churches, synagogues, mosques, and other worship spaces designed during the past 30 years. The book begins with a series of essays on topics ranging from the soundscape of worship spaces to ecclesiastical design at the turn of the 21st Century. Perspective pieces from an architect, audio designer, music director, and worship space owner are also included. The core of the book presents the acoustical and architectural design of a wide variety of individual worship space venues. Acoustical consulting firms, architects, and worship space designers from across the world contributed their recent innovative works in the area of worship space acoustics. The contributions include detailed renderings and architectural drawings, as well as informative acoustic data graphs and evocative descriptions of the spaces. Filled with beautiful photography and fascinating modern design, this book is a must-read for anyone interested in religious architecture, acoustical d...

  16. An Optimisation Approach for Room Acoustics Design

    Holm-Jørgensen, Kristian; Kirkegaard, Poul Henning; Andersen, Lars

    2005-01-01

    This paper discuss on a conceptual level the value of optimisation techniques in architectural acoustics room design from a practical point of view. It is chosen to optimise one objective room acoustics design criterium estimated from the sound field inside the room. The sound field is modeled...

  17. Fresnel Lens Sidewall Design for Imaging Optics

    Fujii, T.; Goulet, A.; Hattori, K.; Konno, K.; Tanaka, A.; Bosmans, R.; Sawada, M.; Yazawa, H.

    2015-03-01

    We developed a ray tracing simulation tool for imaging systems including a Fresnel lens with a quasi-arbitrary sidewall structure. One issue with Fresnel lens is that noise in the image plane can appear from rays passing through or reflected at its sidewalls. One way to reduce it is to modify the orientation of the sidewalls so that rays will not reach the image plane. To find the best sidewall orientations, we developed a method where locally, a sidewall can freely be oriented. We could then derive the best modulation scheme for each Fresnel lens sidewall. In the case of a single imaging Fresnel lens, relative parasite noise intensity could mostly be prevented. To experimentally check our method, snapshot images were taken with single Fresnel lenses and a single spherical lens. No noticeable differences in image quality could be observed using a standard C-MOS camera. However, parasite noise could experimentally be detected with a Fresnel lens prototype when using a very! high-dynamic range C-MOS camera.

  18. LASL lens design procedure: simple, fast, precise, versatile

    Brixner, B.

    1978-11-01

    The Los Alamos Scientific Laboratory general-purpose lens design procedure optimizes specific lens prescriptions to obtain the smallest possible image spots and therefore near-spherical wave fronts of light converging on all images in the field of view. Optical image errors are analyzed in much the same way that they are measured on the optical bench. This lens design method is made possible by using the full capabilities of large electronic computers. First, the performance of the whole lens is sampled with many precisely traced skew rays. Next, lens performance is analyzed with spot diagrams generated by the many rays. Third, lens performance is optimized with a least squares system aimed at reducing all image errors to zero. This statistical approach to lens design uses skew rays and precisely measured ray deviations from ideal image points to achieve greater accuracy than was possible with the classical procedure, which is based on approximate expressions derived from simplified ray traces developed for pencil-and-paper calculations.

  19. Hyperbolic tangential function-based progressive addition lens design.

    Qiu, Gufeng; Cui, Xudong

    2015-12-10

    The diopter distribution is key to the successful design of a progressive addition lens. A hyperbolic tangential function is then introduced to describe well the desired diopter distribution on the lens. Simulation and fabrication show that the astigmia on the whole surface is very close to the addition, exhibiting superior performance than that of currently used high-order polynomials and cosine functions. Our investigations found that once the diopter distribution design is reasonable, both the direct and indirect methods of constructing a progressive addition lens can give consistent results. With this function we are able to effectively control the design of critical areas, the position, sizes of far-view and near-view zones, as well as the channel of the lens. This study would provide an efficient way to customize different progressive lenses not only for presbyopia, but also for anti-fatigue, office progressive usages, etc. PMID:26836863

  20. Unidirectional propagation of designer surface acoustic waves

    Lu, Jiuyang; Ke, Manzhu; Liu, Zhengyou

    2014-01-01

    We propose an efficient design route to generate unidirectional propagation of the designer surface acoustic waves. The whole system consists of a periodically corrugated rigid plate combining with a pair of asymmetric narrow slits. The directionality of the structure-induced surface waves stems from the destructive interference between the evanescent waves emitted from the double slits. The theoretical prediction is validated well by simulations and experiments. Promising applications can be anticipated, such as in designing compact acoustic circuits.

  1. Numerical implementation of generalized Coddington equations for ophthalmic lens design

    Rojo, P.; Royo, S.; Ramírez, J.; Madariaga, I.

    2014-02-01

    A method for general implementation in any software platform of the generalized Coddington equations is presented, developed, and validated within a Matlab environment. The ophthalmic lens design strategy is presented thoroughly, and the basic concepts of generalized ray tracing are introduced. The methodology for ray tracing is shown to include two inter-related processes. Firstly, finite ray tracing is used to provide the main direction of propagation of the considered ray at the incidence point of interest. Afterwards, generalized ray tracing provides the principal curvatures of the local wavefront at that point, and its orientation after being refracted by the lens. The curvature values of the local wavefront are interpreted as the sagital and tangential powers of the lens at the point of interest. The proposed approach is validated using a double-check of the calculated lens performance in the spherical lens case: while finite ray tracing is validated using a commercial ray tracing software, generalized ray tracing is validated using a software application for ophthalmic lens design based on the classical version of Coddington equations. Equations of the complete tracing process are developed in detail for the case of generic astigmatic ophthalmic lenses as an example. Three-dimensional representation of the sagital and tangential powers of the ophthalmic lens at all directions of gaze then becomes possible, and results are presented for lenses with different geometries.

  2. Graphical Acoustic Liner Design and Analysis Tool

    Howerton, Brian M. (Inventor); Jones, Michael G. (Inventor)

    2016-01-01

    An interactive liner design and impedance modeling tool comprises software utilized to design acoustic liners for use in constrained spaces, both regularly and irregularly shaped. A graphical user interface allows the acoustic channel geometry to be drawn in a liner volume while the surface impedance calculations are updated and displayed in real-time. A one-dimensional transmission line model may be used as the basis for the impedance calculations.

  3. Acoustic excitation of the circular Bragg endash Fresnel lens in backscattering geometry

    An increment of the x-ray flux in crystal Bragg endash Fresnel lens (BFL) focus in backscattering geometry obtained by means of acoustic excitation of the BFL crystal substrate has been investigated. The dependence of the x ray close-quote s total reflected power versus ultrasound parameters has been studied in a low frequency range (10 endash 50 MHz). The proposed technique allows an increase in the flux in a BFL focus by a factor of 2 which almost achieves the kinematic limit. copyright 1997 American Institute of Physics

  4. Magnifying perfect lens and superlens design by coordinate transformation

    Tsang, Mankei

    2007-01-01

    The coordinate transformation technique is applied to the design of perfect lenses and superlenses. In particular, anisotropic metamaterials that magnify planar images beyond the diffraction limit are designed by the use of oblate spheroidal coordinates. The oblate spheroidal perfect lens or superlens can naturally be used in reverse for lithography of planar subwavelength patterns.

  5. Magnifying perfect lens and superlens design by coordinate transformation

    Tsang, Mankei; Psaltis, Demetri

    2008-01-01

    The coordinate transformation technique is applied to the design of perfect lenses and superlenses. In particular, anisotropic metamaterials that magnify two-dimensional planar images beyond the diffraction limit are designed by the use of oblate spheroidal coordinates. The oblate spheroidal perfect lens or superlens can naturally be used in reverse for lithography of planar subwavelength patterns.

  6. Techniques for analyzing lens manufacturing data with optical design applications

    Kaufman, Morris I.; Light, Brandon B.; Malone, Robert M.; Gregory, Michael K.; Frayer, Daniel K.

    2015-09-01

    Optical designers assume a mathematically derived statistical distribution of the relevant design parameters for their Monte Carlo tolerancing simulations. However, there may be significant differences between the assumed distributions and the likely outcomes from manufacturing. Of particular interest for this study are the data analysis techniques and how they may be applied to optical and mechanical tolerance decisions. The effect of geometric factors and mechanical glass properties on lens manufacturability will be also be presented. Although the present work concerns lens grinding and polishing, some of the concepts and analysis techniques could also be applied to other processes such molding and single-point diamond turning.

  7. Conceptual design of a beam steering lens through transformation electromagnetics.

    Yi, Jianjia; Burokur, Shah Nawaz; de Lustrac, André

    2015-05-18

    In this paper, based on transformation electromagnetics, the design procedure of a lens antenna, which steers the radiated beam of a patch array, is presented. Laplace's equation is adopted to construct the mapping between the virtual space and the physical space. The two dimensional (2D) design method can be extended to a potential three-dimensional (3D) realization, and with a proper parameter simplification, the lens can be further realized by common metamaterials or isotropic graded refractive index (GRIN) materials. Full wave simulations are performed to validate the proposed concept. It is observed that by placing the lens on a feeding source, we are able to steer the radiation emitted by the latter source. PMID:26074547

  8. Acoustic design by topology optimization

    Dühring, Maria Bayard; Jensen, Jakob Søndergaard; Sigmund, Ole

    2008-01-01

    To bring down noise levels in human surroundings is an important issue and a method to reduce noise by means of topology optimization is presented here. The acoustic field is modeled by Helmholtz equation and the topology optimization method is based on continuous material interpolation functions...... outdoor sound barriers and reduce the sound level in the shadow zone behind the barrier up to 10 dB for a single barrier and almost 30 dB when using 2 barriers compared to utilizing conventional sound barriers....

  9. Design and development of a laminated Fresnel lens for point-focus PV systems. Phase II

    Hodge, R.C.

    1982-12-01

    A laminated glass-plastic lens parquet using injection molded point focus Fresnel lenses is described. The second phase of a program aimed at investigating the cost effectiveness of a glass-plastic concentrator lens assembly is reported. The first phase dealt with the development of a first generation lens design, the selection of the preferred glass coverplate and glass-to-lens adhesive and initial injection molding lens molding trials. The second phase has dealt with the development of an improved lens design, a full size parquet lamination process, and a second group of injection molding lens molding trials.

  10. Electrostatic afocal-zoom lens design using computer optimization technique

    Sise, Omer, E-mail: omersise@gmail.com

    2014-12-15

    Highlights: • We describe the detailed design of a five-element electrostatic afocal-zoom lens. • The simplex optimization is used to optimize lens voltages. • The method can be applied to multi-element electrostatic lenses. - Abstract: Electron optics is the key to the successful operation of electron collision experiments where well designed electrostatic lenses are needed to drive electron beam before and after the collision. In this work, the imaging properties and aberration analysis of an electrostatic afocal-zoom lens design were investigated using a computer optimization technique. We have found a whole new range of voltage combinations that has gone unnoticed until now. A full range of voltage ratios and spherical and chromatic aberration coefficients were systematically analyzed with a range of magnifications between 0.3 and 3.2. The grid-shadow evaluation was also employed to show the effect of spherical aberration. The technique is found to be useful for searching the optimal configuration in a multi-element lens system.

  11. Student design projects in applied acoustics.

    Bös, Joachim; Moritz, Karsten; Skowronek, Adam; Thyes, Christian; Tschesche, Johannes; Hanselka, Holger

    2012-03-01

    This paper describes a series of student projects which are intended to complement theoretical education in acoustics and engineering noise control with practical experience. The projects are also intended to enhance the students' ability to work in a team, to manage a project, and to present their results. The projects are carried out in close cooperation with industrial partners so that the students can get a taste of the professional life of noise control engineers. The organization of such a project, its execution, and some of the results from the most recent student project are presented as a demonstrative example. This latest project involved the creation of noise maps of a production hall, the acoustic analysis of a packaging machine, and the acoustic analysis of a spiral vibratory conveyor. Upon completion of the analysis, students then designed, applied, and verified some simple preliminary noise reduction measures to demonstrate the potential of these techniques. PMID:22423803

  12. Systematic design of acoustic devices by topology optimization

    Jensen, Jakob Søndergaard; Sigmund, Ole

    2005-01-01

    We present a method to design acoustic devices with topology optimization. The general algorithm is exemplified by the design of a reflection chamber that minimizes the transmission of acoustic waves in a specified frequency range....

  13. ACOUSTICS IN ARCHITECTURAL DESIGN, AN ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS.

    DOELLE, LESLIE L.

    THE PURPOSE OF THIS ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS WAS--(1) TO COMPILE A CLASSIFIED BIBLIOGRAPHY, INCLUDING MOST OF THOSE PUBLICATIONS ON ARCHITECTURAL ACOUSTICS, PUBLISHED IN ENGLISH, FRENCH, AND GERMAN WHICH CAN SUPPLY A USEFUL AND UP-TO-DATE SOURCE OF INFORMATION FOR THOSE ENCOUNTERING ANY ARCHITECTURAL-ACOUSTIC DESIGN…

  14. Compact acoustic antenna design using labyrinthine metamaterials

    Ren, Chunyu

    2015-05-01

    We present an effective design and architecture for a class of acoustic antennas in air. The work begins with a conformal transformation method that yields the preliminary design, which is constructed using an isotropic but inhomogeneous material. However, the desired material parameters have been unavailable until now. Here we show that by scaling up the refractive index and optimizing the geometry in the preliminary design, a series of square antennas can be achieved to exhibit an excellent beam-collimating effect. An important part of our strategy is that the device's thickness and material properties can be tailored easily to greatly facilitate its realization. It is also demonstrated that the proposed antenna can be made very thin and readily implemented using labyrinthine acoustic metamaterials.

  15. A design study of a magnifying magnetic lens for proton radiography

    YANG Guo-Jun; ZHANG Zhuo; WEI Tao; HE Xiao-Zhong; LONG Ji-Dong; SHI Jin-Shui; ZHANG Kai-Zhi

    2012-01-01

    Magnifying magnetic lenses can be used in high-energy proton microscopes.The -I lens suggested by Zumbro is analyzed in this paper,and a new type of magnetic lens called a lengthened lens is introduced.Theoretical analysis shows that the lengthened lens can form a magnifying lens,and at the same time the main advantages of a Zumbro lens are inherited.Using the My-BOC beam dynamics code,an example of the design is shown.The results show that the method of designing magnifying magnetic lenses is effective.

  16. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  17. Design of Novel Compound Fresnel Lens for High-Performance Photovoltaic Concentrator

    Lei Jing; Hua Liu; Huifu Zhao; Zhenwu Lu; Hongsheng Wu; He Wang; Jialin Xu

    2012-01-01

    We present a new design of compound Fresnel-R concentrator which is composed of two lenses: a primary lens (Fresnel lens) that works by total internal reflection at outer sawteeth but refraction at inner sawteeth, and a ringed secondary lens that works by refraction. In contrast to previous Fresnel lens concentrators, this design increases the acceptance angle, improves the irradiance uniformity on the solar cell, and reduces the aspect ratio significantly. Meanwhile several sawteeth of the p...

  18. Progressive addition lens design by optimizing NURBS surface

    Liu, Yen-Liang; Hsu, Wei-Yao; Cheng, Yuan-Chieh; Su, Guo-Dung

    2011-10-01

    Progressive addition lenses (PAL) are used to compensate presbyopia, which is induced by losing accommodation of elder eyes. These eyes need different optical power provided by eye glasses while watching objects at different distance. A smaller optical power is required in further distance and a larger one in nearer zone. A progressive addition lens can provides different power requirements in one piece of lens. This paper introduces a whole process of PAL production, from design, fabrication, to measurement. The PAL is designed by optimizing NURBS surface. Parameters of merit function are adjusted to design lenses with different specifications. The simulation results confirm that the power distributes as expected and cylinders are controlled under an acceptable level. Besides, sample lenses have been fabricated and measured. We apply precise-machining to produce the molds for plastic injection. Then, the samples are produced by injecting polycorbonate to the molds. Finally, Ultra Accuracy 3D Profilemeter is used to measure the sample PALs. Practical examinations shows that our designs are achievable and feasible in practice use.

  19. Design of a Test Bench for Intraocular Lens Optical Characterization

    Alba-Bueno, Francisco; Vega, Fidel; Millán, María S.

    2011-01-01

    The crystalline lens is the responsible for focusing at different distances (accommodation) in the human eye. This organ grows throughout life increasing in size and rigidity. Moreover, due this growth it loses transparency through life, and becomes gradually opacified causing what is known as cataracts. Cataract is the most common cause of visual loss in the world. At present, this visual loss is recoverable by surgery in which the opacified lens is destroyed (phacoemulsification) and replaced by the implantation of an intraocular lens (IOL). If the IOL implanted is mono-focal the patient loses its natural capacity of accommodation, and as a consequence they would depend on an external optic correction to focus at different distances. In order to avoid this dependency, multifocal IOLs designs have been developed. The multi-focality can be achieved by using either, a refractive surface with different radii of curvature (refractive IOLs) or incorporating a diffractive surface (diffractive IOLs). To analyze the optical quality of IOLs it is necessary to test them in an optical bench that agrees with the ISO119679-2 1999 standard (Ophthalmic implants. Intraocular lenses. Part 2. Optical Properties and Test Methods). In addition to analyze the IOLs according to the ISO standard, we have designed an optical bench that allows us to simulate the conditions of a real human eye. To do that, we will use artificial corneas with different amounts of optical aberrations and several illumination sources with different spectral distributions. Moreover, the design of the test bench includes the possibility of testing the IOLs under off-axis conditions as well as in the presence of decentration and/or tilt. Finally, the optical imaging quality of the IOLs is assessed by using common metrics like the Modulation Transfer Function (MTF), the Point Spread Function (PSF) and/or the Strehl ratio (SR), or via registration of the IOL's wavefront with a Hartmann-Shack sensor and its

  20. Design of a Test Bench for Intraocular Lens Optical Characterization

    The crystalline lens is the responsible for focusing at different distances (accommodation) in the human eye. This organ grows throughout life increasing in size and rigidity. Moreover, due this growth it loses transparency through life, and becomes gradually opacified causing what is known as cataracts. Cataract is the most common cause of visual loss in the world. At present, this visual loss is recoverable by surgery in which the opacified lens is destroyed (phacoemulsification) and replaced by the implantation of an intraocular lens (IOL). If the IOL implanted is mono-focal the patient loses its natural capacity of accommodation, and as a consequence they would depend on an external optic correction to focus at different distances. In order to avoid this dependency, multifocal IOLs designs have been developed. The multi-focality can be achieved by using either, a refractive surface with different radii of curvature (refractive IOLs) or incorporating a diffractive surface (diffractive IOLs). To analyze the optical quality of IOLs it is necessary to test them in an optical bench that agrees with the ISO119679-2 1999 standard (Ophthalmic implants. Intraocular lenses. Part 2. Optical Properties and Test Methods). In addition to analyze the IOLs according to the ISO standard, we have designed an optical bench that allows us to simulate the conditions of a real human eye. To do that, we will use artificial corneas with different amounts of optical aberrations and several illumination sources with different spectral distributions. Moreover, the design of the test bench includes the possibility of testing the IOLs under off-axis conditions as well as in the presence of decentration and/or tilt. Finally, the optical imaging quality of the IOLs is assessed by using common metrics like the Modulation Transfer Function (MTF), the Point Spread Function (PSF) and/or the Strehl ratio (SR), or via registration of the IOL's wavefront with a Hartmann-Shack sensor and its

  1. Design of a Test Bench for Intraocular Lens Optical Characterization

    Alba-Bueno, Francisco; Vega, Fidel; Millan, Maria S, E-mail: francisco.alba-bueno@upc.edu, E-mail: fvega@oo.upc.edu, E-mail: millan@oo.upc.edu [Departamento de Optica y Optometria, Universidad Politecnica de Cataluna, C/ Violinista Vellsola 37, 08222 Terrassa (Spain)

    2011-01-01

    The crystalline lens is the responsible for focusing at different distances (accommodation) in the human eye. This organ grows throughout life increasing in size and rigidity. Moreover, due this growth it loses transparency through life, and becomes gradually opacified causing what is known as cataracts. Cataract is the most common cause of visual loss in the world. At present, this visual loss is recoverable by surgery in which the opacified lens is destroyed (phacoemulsification) and replaced by the implantation of an intraocular lens (IOL). If the IOL implanted is mono-focal the patient loses its natural capacity of accommodation, and as a consequence they would depend on an external optic correction to focus at different distances. In order to avoid this dependency, multifocal IOLs designs have been developed. The multi-focality can be achieved by using either, a refractive surface with different radii of curvature (refractive IOLs) or incorporating a diffractive surface (diffractive IOLs). To analyze the optical quality of IOLs it is necessary to test them in an optical bench that agrees with the ISO119679-2 1999 standard (Ophthalmic implants. Intraocular lenses. Part 2. Optical Properties and Test Methods). In addition to analyze the IOLs according to the ISO standard, we have designed an optical bench that allows us to simulate the conditions of a real human eye. To do that, we will use artificial corneas with different amounts of optical aberrations and several illumination sources with different spectral distributions. Moreover, the design of the test bench includes the possibility of testing the IOLs under off-axis conditions as well as in the presence of decentration and/or tilt. Finally, the optical imaging quality of the IOLs is assessed by using common metrics like the Modulation Transfer Function (MTF), the Point Spread Function (PSF) and/or the Strehl ratio (SR), or via registration of the IOL's wavefront with a Hartmann-Shack sensor and its

  2. Designated Communities”: Through the Lens of the Web

    Yunhyong Kim

    2015-02-01

    Full Text Available The notion of a “designated community” has always been a rather elusive concept across the digital curation landscape. This paper is an effort to revisit the concept to stir up new discussions in the area. More specifically, this study offers a perspective on designated communities through the lens of the web, powered by developments in the last ten years in social media. The research presents a multi-faceted analysis of communities based on HTML content from online web pages to propose heuristics for defining designated communities based on the technology they adopt, properties of knowledge organisation, and how they link to each other. This impacts the building of quantifiable models of designated communities, estimating curation risks associated to the community and further, refining approaches to preservation strategies that meet the needs of the community.

  3. Internet based post-graduate course in spectacle lens design

    Jalie, Mo

    2014-07-01

    The complexity of spectacle lenses has increased enormously over the last three decades. The advent of aspheric lenses for the normal power range and the, now commonplace, progressive lenses for the correction of presbyopia, are just two examples of 21st Century technology. Freeform surfaces are now employed to personalize lenses to wearer's needs and these may be both progressive and atoroidal in nature. At the same time, optometry has taken a sideways step from optics and physics into a more general primary health care profession with an ever-increasing amount of biological and medical content added to an already brimming curriculum, hence the need for persons without optometry training to undertake the study of spectacle lenses. Some years ago a post-graduate course was designed for opticians who had a good grasp of mathematics and the ability to pay close attention to detail in the lengthy trigonometric ray-tracing techniques employed in lens design calculations. The year-long course, is undertaken by distance learning, and has been undertaken via the internet by students from many countries around the world. Final assessment is by means of examination held by the Association of British Dispensing Opticians and takes the form of two three-hour papers, Paper One consisting of the determination of the aberrations of a spectacle lens by accurate trigonometric ray tracing and the second, a general paper on the optics of ophthalmic lenses. It leads to the professional qualification, ABDO (Hons) SLD.

  4. A framework of cloud supported collaborative design in glass lens moulds based on aspheric measurement

    Zhu, Yongjian; Wang, Yu; Na, Jingxin; Zhi, Yanan; Fan, Yufeng

    2013-09-01

    Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD), computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module (FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM), optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.

  5. Design of lens-hood in the space fisheye optical system

    Zhu, Qing; Zhang, Zhao-hui; Zhang, Zhi; Yan, Aqi; Cao, Jian-zhong; Zhang, Kai-sheng

    2013-09-01

    Due to the extra wide field of view, fisheye optical systems are appropriately applied in space camera for scouting large-scale objects with near-distance. At the same time, because of the violent sunlight linger within the field of view more than other optical system and more stray light occur during the period, to design proper lens-hood can effectively reduce the sunshine time. Another distinct characteristic of fisheye optical system is the first protrude lens, which is contrived with negative focus to trace the ray with angle about even above 90 degree of incidence. Consequently, the first lens is in danger of damaging by scratching when operating the camera during the ground experiments without lens-hood. Whereas on account of the huge distortion which is the third mainly characteristic of fisheye optical system, to design appropriate lens-hood is a tough work comparing with other low-distortion optical system, especially for those whose half diagonal field is more than 90°. In this paper, an research carried out on the design lens-hood for fisheye is proposed. In the way of reverse ray-tracing, the location on the first lens and point-vector for each incident ray can be accurately calculated. Thus the incident ray intersecting the first lens corresponds to the boundary of the image sensor form the effective object space. According to the figure of the lens and the incident rays, the lens-hood can be confirmed. In the proposed method, a space fisheye lens is presented as a typical lens, whose horizontal field and vertical field are 134°, diagonal field is up to 192°, respectively. The results of design for the lens-hood show that the lingering time of sunshine is shorten because of obstructing some redundant sunlight, and the first outstanding lens are protected in the most degree.

  6. Peripheral myopization using a dominant design multifocal contact lens

    Lopes-Ferreira, Daniela; Ribeiro, Cláudia; Maia, Raquel; García-Porta, Nery; Queirós, António; Villa-Collar, César; González-Méijome, José Manuel

    2011-01-01

    Purpose The purpose of this study was to characterize the central and peripheral refraction across the horizontal meridian of the visual field without and with a multifocal dominant design soft contact lens of different add powers (+1.00 D to +4.00 D) in emmetropic eyes. Methods Twenty right eyes from 20 emmetropic patients (mean spherical equivalent central refraction –0.06 ± 0.54 D) with a mean age of 21.6 ± 2.3 years were fitted with Proclear Multifocal dominant design (Coopervision, Pleasanton, CA, USA). Lenses had add powers from +1.00 to +4.00 D in 1.00 D steps. The central and peripheral refraction was measured along the horizontal meridian up to 35° of eccentricity in the nasal and temporal retinal area in 5° steps using a open-field autorefractometer. Results Only the +3.00 and +4.00 D add powers generated a significant change in the peripheral refractive pattern compared to central refraction and compared with the no-lens wearing situation. The average myopic increase with these lenses was –3.00 D and –5.00 (p < 0.001) at the margins of inspected nasal and temporal visual field, respectively. Conclusions Multifocal dominant design soft contact lenses are able to change the peripheral refractive profile in emmetropic eyes increasing relative peripheral myopia. Lenses with +3.00 D add power seem to be the best option to create such effect due to significant peripheral myopization.

  7. Fresnel Lens Solar Concentrator Design Based on Geometric Optics and Blackbody Radiation Equations

    Watson, Michael D.; Jayroe, Robert, Jr.

    1999-01-01

    Fresnel lenses have been used for years as solar concentrators in a variety of applications. Several variables effect the final design of these lenses including: lens diameter, image spot distance from the lens, and bandwidth focused in the image spot. Defining the image spot as the geometrical optics circle of least confusion and applying blackbody radiation equations the spot energy distribution can be determined. These equations are used to design a fresnel lens to produce maximum flux for a given spot size, lens diameter, and image distance. This approach results in significant increases in solar efficiency over traditional single wavelength designs.

  8. Double freeform surfaces lens design for LED uniform illumination with high distance-height ratio

    Wu, Heng; Zhang, Xianmin; Ge, Peng

    2015-10-01

    A practical method is proposed to design a double freeform surfaces (DFS) lens for LED sources, in order to form uniform illumination in the high distance-height ratio (DHR) lighting system. The ray mapping relationship is first established between the solid angle of the source and the target plane according to the energy conservation law and the variable separation method. A DFS lens is then constructed simultaneously and point by point to the ray mapping based on the Snell's law. Optical performance of the lens is investigated by the Monte Carlo method. A simple and effective method is utilized to optimize the lens design in accordance with the simulation results. As an example, a DFS lens with DHR of 2.5 (distance 30 mm, height 12 mm) is designed by the proposed method. Compared with the traditional methods, the illuminance uniformity is significantly improved from 67.20% to 86.43% and the size of the lens is dramatically reduced.

  9. An Ultrasonic Lens Design Based on Prefractal Structures

    Sergio Castiñeira-Ibáñez

    2016-04-01

    Full Text Available The improvement in focusing capabilities of a set of annular scatterers arranged in a fractal geometry is theoretically quantified in this work by means of the finite element method (FEM. Two different arrangements of rigid rings in water are used in the analysis. Thus, both a Fresnel ultrasonic lens and an arrangement of rigid rings based on Cantor prefractals are analyzed. Results show that the focusing capacity of the modified fractal lens is better than the Fresnel lens. This new lens is believed to have potential applications for ultrasonic imaging and medical ultrasound fields.

  10. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface.

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A

    2014-01-01

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications. PMID:25418084

  11. Acoustic Treatment Design Scaling Methods. Phase 2

    Clark, L. (Technical Monitor); Parrott, T. (Technical Monitor); Jones, M. (Technical Monitor); Kraft, R. E.; Yu, J.; Kwan, H. W.; Beer, B.; Seybert, A. F.; Tathavadekar, P.

    2003-01-01

    The ability to design, build and test miniaturized acoustic treatment panels on scale model fan rigs representative of full scale engines provides not only cost-savings, but also an opportunity to optimize the treatment by allowing multiple tests. To use scale model treatment as a design tool, the impedance of the sub-scale liner must be known with confidence. This study was aimed at developing impedance measurement methods for high frequencies. A normal incidence impedance tube method that extends the upper frequency range to 25,000 Hz. without grazing flow effects was evaluated. The free field method was investigated as a potential high frequency technique. The potential of the two-microphone in-situ impedance measurement method was evaluated in the presence of grazing flow. Difficulties in achieving the high frequency goals were encountered in all methods. Results of developing a time-domain finite difference resonator impedance model indicated that a re-interpretation of the empirical fluid mechanical models used in the frequency domain model for nonlinear resistance and mass reactance may be required. A scale model treatment design that could be tested on the Universal Propulsion Simulator vehicle was proposed.

  12. On architectural acoustic design using computer simulation

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2004-01-01

    discusses the advantages and disadvantages of the programme in each phase compared to the works of architects not using acoustic simulation programmes. The conclusion of the paper is that the application of acoustic simulation programs is most beneficial in the last of three phases but an application of the...

  13. Design of high-resolution Fourier transform lens

    Zhang, Lei; Zhong, Xing; Jin, Guang

    2007-12-01

    With the development of optical information processing, high-resolution Fourier transform lens has often been used in holographic data storage system, spatial filtering and observation of particles. This paper studies the optical design method of high-resolution Fourier transform optical lenses system, which could be used in particles observation and holographic data storage system. According to Fourier transform relation between object and its frequency plane and the theory of geometrical optics, the system with working wavelength 532nm and resolution 3μm was designed based on ZEMAX. A multi-configuration method was adopted to optimize the system's lenses. In the optical system, a diaphragm was placed at the system's spectrum plane and the system demanded a low vacuum to cut down the influences of atmosphere and other particles. The result of finite element analysis indicated that the influences of vacuum pumping to optics spacing and mirror surface shape very minor, and the imaging quality not being affected. This system has many advantages, such as simple structure, good image quality and a high resolution of 3μm. So it has a wide application prospect and can be used both in holographic data storage system and particles observation.

  14. Three-dimensional Ultrathin Planar Lenses by Acoustic Metamaterials

    Li, Yong; Yu, Gaokun; Liang, Bin; Zou, Xinye; Li, Guangyun; Cheng, Su; Cheng, Jianchun

    2014-01-01

    Acoustic lenses find applications in various areas ranging from ultrasound imaging to nondestructive testing. A compact-size and high-efficient planar acoustic lens is crucial to achieving miniaturization and integration, and should have deep implication for the acoustic field. However its realization remains challenging due to the trade-off between high refractive-index and impedance-mismatch. Here we have designed and experimentally realized the first ultrathin planar acoustic lens capable ...

  15. Initial Design of an Acoustic Communication Channel Simulator

    Bertolotto, G.; Jenserud, T.; Walree, P.A. van

    2007-01-01

    The joint European project “UUV Covert Acoustic Communications” aims at the design of an acoustic communication system between an unmanned underwater vehicle and a support mother ship. To achieve the objective of covert communication over long ranges in littoral waters, knowledge is required on the

  16. Digital sonar design in underwater acoustics principles and applications

    Li, Qihu

    2012-01-01

    "Digital Sonar Design in Underwater Acoustics Principles and Applications" provides comprehensive and up-to-date coverage of research on sonar design, including the basic theory and techniques of digital signal processing, basic concept of information theory, ocean acoustics, underwater acoustic signal propagation theory, and underwater signal processing theory. This book discusses the general design procedure and approaches to implementation, the design method, system simulation theory and techniques, sonar tests in the laboratory, lake and sea, and practical validation criteria and methods for digital sonar design. It is intended for researchers in the fields of underwater signal processing and sonar design, and also for navy officers and ocean explorers. Qihu Li is a professor at the Institute of Acoustics, Chinese Academy of Sciences, and an academician of the Chinese Academy of Sciences.

  17. International Lens Design Conference, Monterey, CA, June 11-14, 1990, Proceedings

    Lawrence, George N.

    The present conference on lens design encompasses physical and geometrical optics, diffractive optics, the optimization of optical design, software packages, ray tracing, the use of artificial intelligence, the achromatization of materials, zoom optics, microoptics and GRIN lenses, and IR lens design. Specific issues addressed include diffraction-performance calculations in lens design, the optimization of the optical transfer function, a rank-down method for automatic lens design, applications of quadric surfaces, the correction of aberrations by using HOEs in UV and visible imaging systems, and an all-refractive telescope for intersatellite communications. Also addressed are automation techniques for optics manufacturing, all-reflective phased-array imaging telescopes, the thermal aberration analysis of a Nd:YAG laser, the analysis of illumination systems, athermalized FLIR optics, and the design of array systems using shared symmetry.

  18. The need for good acoustic design of schools

    Shield, Bridget

    2005-04-01

    This paper gives an overview of research into classroom acoustics, highlighting the importance of a good acoustic environment in schools to enhance teaching and learning. The paper is aimed at a general audience of people interested in education and school design. In the past 30 years there has been a great deal of research into the effects of noise and poor acoustics in schools on children and teachers. It has been shown in many studies that children have difficulty hearing and understanding their teachers in noise, and both external environmental noise and noise within a school affect children's academic performance. Furthermore many teachers suffer from voice and throat problems which may be attributable to a poor acoustic environment in the classroom. The acoustic design of a classroom has a direct influence upon noise levels and the intelligibility of speech. Poor sound insulation and excessive reverberation have the potential to increase noise levels and reduce speech intelligibility. However, despite the introduction in many countries of legislation or guidelines for acoustic design of schools, in general acoustics still has a low priority in school design and many schools, old and new, fail to meet the current standards.

  19. Design and demonstration of broadband thin planar diffractive acoustic lenses

    Wang, Wenqi; Xie, Yangbo; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A., E-mail: cummer@ee.duke.edu [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2014-09-08

    We present here two diffractive acoustic lenses with subwavelength thickness, planar profile, and broad operation bandwidth. Tapered labyrinthine unit cells with their inherently broadband effective material properties are exploited in our design. Both the measured and the simulated results are showcased to demonstrate the lensing effect over more than 40% of the central frequency. The focusing of a propagating Gaussian modulated sinusoidal pulse is also demonstrated. This work paves the way for designing diffractive acoustic lenses and more generalized phase engineering diffractive elements with labyrinthine acoustic metamaterials.

  20. Design and demonstration of broadband thin planar diffractive acoustic lenses

    We present here two diffractive acoustic lenses with subwavelength thickness, planar profile, and broad operation bandwidth. Tapered labyrinthine unit cells with their inherently broadband effective material properties are exploited in our design. Both the measured and the simulated results are showcased to demonstrate the lensing effect over more than 40% of the central frequency. The focusing of a propagating Gaussian modulated sinusoidal pulse is also demonstrated. This work paves the way for designing diffractive acoustic lenses and more generalized phase engineering diffractive elements with labyrinthine acoustic metamaterials.

  1. Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

    Carlson, Thomas J.; Yong Yuan; Zhiqun Daniel Deng; Huidong Li

    2012-01-01

    PZT ceramics have been widely used in underwater acoustic transducers. However, literature available discussing the design parameters of a miniaturized PZT-based low-duty-cycle transmitter is very limited. This paper discusses some of the design parameters—the backing material, driving voltage, PZT material type, power consumption and the transducer length of a miniaturized acoustic fish tag using a PZT tube. Four different types of PZT were evaluated with respect to the source level, energy ...

  2. Two-lens designs for modern uncooled and cooled IR imaging devices

    Schuster, Norbert; Franks, John

    2013-10-01

    In recent years, thermal detectors with a 17 μm pixel pitch have become well-established for use in various applications, such as thermal imaging in cars. This has allowed the civilian infrared market to steadily mature. The main cost for these lens designs comes from the number of lenses used. The development of thermal detectors, which are less sensitive than quantum detectors, has compelled camera manufacturers to demand very fast F-numbers such as f/1.2 or faster. This also minimizes the impact of diffraction in the 8-12 μmm waveband. The freedom afforded by the choice of the stop position in these designs has been used to create high-resolution lenses that operate near the diffraction limit. Based on GASIR®1, a chalcogenide glass, two-lens designs have been developed for all pixel counts and fields of view. Additionally, all these designs have been passively athermalized, either optically or mechanically. Lenses for cooled quantum detectors have a defined stop position called the cold stop (CS) near the FPA-plane. The solid angle defined by the CS fixes not only the F-number (which is less fast than for thermal detectors), but determines also the required resolution. The main cost driver of these designs is the lens diameter. Lenses must be sufficiently large to avoid any vignetting of ray bundles intended to reach the cooled detector. This paper studies the transfer of approved lens design principles for thermal detectors to lenses for cooled quantum detectors with CS for same pixel count at three horizontal fields of view: a 28° medium field lens, an 8° narrow field lens, and a 90° wide field lens. The lens arrangements found for each category have similar lens costs.

  3. STRONG LENS TIME DELAY CHALLENGE. I. EXPERIMENTAL DESIGN

    Dobler, Gregory [Kavli Institute for Theoretical Physics, University of California Santa Barbara, Santa Barbara, CA 93106 (United States); Fassnacht, Christopher D.; Rumbaugh, Nicholas [Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616 (United States); Treu, Tommaso; Liao, Kai [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Marshall, Phil [Kavli Institute for Particle Astrophysics and Cosmology, P.O. Box 20450, MS29, Stanford, CA 94309 (United States); Hojjati, Alireza [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, B.C. V6T 1Z1 (Canada); Linder, Eric, E-mail: tt@astro.ucla.edu [Lawrence Berkeley National Laboratory and University of California, Berkeley, CA 94720 (United States)

    2015-02-01

    The time delays between point-like images in gravitational lens systems can be used to measure cosmological parameters. The number of lenses with measured time delays is growing rapidly; the upcoming Large Synoptic Survey Telescope (LSST) will monitor ∼10{sup 3} strongly lensed quasars. In an effort to assess the present capabilities of the community, to accurately measure the time delays, and to provide input to dedicated monitoring campaigns and future LSST cosmology feasibility studies, we have invited the community to take part in a ''Time Delay Challenge'' (TDC). The challenge is organized as a set of ''ladders'', each containing a group of simulated data sets to be analyzed blindly by participating teams. Each rung on a ladder consists of a set of realistic mock observed lensed quasar light curves, with the rungs' data sets increasing in complexity and realism. The initial challenge described here has two ladders, TDC0 and TDC1. TDC0 has a small number of data sets, and is designed to be used as a practice set by the participating teams. The (non-mandatory) deadline for completion of TDC0 was the TDC1 launch date, 2013 December 1. The TDC1 deadline was 2014 July 1. Here we give an overview of the challenge, we introduce a set of metrics that will be used to quantify the goodness of fit, efficiency, precision, and accuracy of the algorithms, and we present the results of TDC0. Thirteen teams participated in TDC0 using 47 different methods. Seven of those teams qualified for TDC1, which is described in the companion paper.

  4. On Architectural Acoustics Design using Computer Simulation

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2004-01-01

    architect without this information is discussed. The conclusion of the paper is that the application of acoustical simulation programs is most beneficial in the last of three phases but that an application of the program to the two first phases would be preferable and possible with an improvement of the...

  5. Strong Lens Time Delay Challenge: I. Experimental Design

    Dobler, Gregory; Treu, Tommaso; Marshall, Phillip J; Liao, Kai; Hojjati, Alireza; Linder, Eric; Rumbaugh, Nicholas

    2013-01-01

    The time delays between point-like images in gravitational lens systems can be used to measure cosmological parameters as well as probe the dark matter (sub-)structure within the lens galaxy. The number of lenses with measured time delays is growing rapidly as a result of some dedicated efforts; the upcoming Large Synoptic Survey Telescope (LSST) will monitor ~1000 lens systems consisting of a foreground elliptical galaxy producing multiple images of a background quasar. In an effort to assess the present capabilities of the community to accurately measure the time delays in strong gravitational lens systems, and to provide input to dedicated monitoring campaigns and future LSST cosmology feasibility studies, we invite the community to take part in a "Time Delay Challenge" (TDC). The challenge is organized as a set of "ladders", each containing a group of simulated datasets to be analyzed blindly by participating independent analysis teams. Each rung on a ladder consists of a set of realistic mock observed le...

  6. Lens designs by ray tracing analyses for high-performance reflection optical modules

    Three kinds of novel optical modules are designed for high-efficiency light concentration. Each optical module consists of three components, namely a reflector, a second optical element (SOE) with a different parabolic profile and a concentrating lens. A concentrating lens with various profile designs is installed at the open end of the reflector to improve the uniformity of ray irradiances collected at the solar cell chip. An effective process for finding the optimum design for the geometries of these optical modules is presented to obtain good uniformity in ray irradiance distribution and high optical performance. The results of ray tracing simulations indicate that the optimum design is achieved based on the principle or the compromise of having the lowest value of the highest peak of ray irradiances and the highest optical performance. The optical module designed without a concentrating lens has a relatively high peak at the center of the circular irradiance distribution. The use of a Fresnel lens can impede the high peak effectively and achieve very good optical performance. Modules with spherical and aspherical concentrating lenses have irradiance peaks that are much higher than that of the Fresnel lens although their performance is negligibly higher than that of the Fresnel lens

  7. Design of the Acoustic Signal Receiving Unit of Acoustic Telemetry While Drilling

    Li Zhigang

    2016-01-01

    Full Text Available Signal receiving unit is one of the core units of the acoustic telemetry system. A new type of acoustic signal receiving unit is designed to solve problems of the existing devices. The unit is a short joint in whole. It not only can receive all the acoustic signals transmitted along the drill string, without losing any signal, but will not bring additional vibration and interference. In addition, the structure of the amplitude transformer is designed, which can amplify the signal amplitude and improve the receiving efficiency. The design of the wireless communication module makes the whole device can be used in normal drilling process when the drill string is rotating. So, it does not interfere with the normal drilling operation.

  8. Analysis, Design and Fabrication of centimeter-wave Dielectric Fresnel Zone Plate Lens and reflector

    Mahmoudi, Ali; Azalzadeh, Reza

    2007-01-01

    Fresnel lens has a long history in optics. This concept at non-optical wavelengths is also applicable. In this paper we report design and fabrication of a half and quarter wave dielectric Fresnel lens made of Plexiglas, and a Fresnel reflector at 11.1 GHz frequency. We made two lenses and one reflector at same frequency and compare their gain and radiation pattern to simulated results. Some methods for better focusing action will be introduced.

  9. Analysis, Design and Fabrication of centimeter-wave Dielectric Fresnel Zone Plate Lens and reflector

    Mahmoudi, A; Mahmoudi, Ali; Azalzadeh, Reza

    2005-01-01

    Fresnel lens has a long history in optics. This concept at non-optical wavelengths is also applicable. In this paper we report design and fabrication of a half and quarter wave dielectric Fresnel lens made of Plexiglas, and a Fresnel reflector at 11.1 GHz frequency. We made two lenses and one reflector at same frequency and compare their gain and radiation pattern to simulated results. Some methods for better focusing action will be introduced.

  10. Parametric fuselage design: Integration of mechanics and acoustic & thermal insulation

    Krakers, L.A.

    2009-01-01

    Designing a fuselage is a very complex process, which involves many different aspects like strength and stability, fatigue, damage tolerance, fire resistance, thermal and acoustic insulation but also inspection, maintenance, production and repair aspects. It is difficult to include all design aspect

  11. Design of a new two element OSLD Badge for eye lens monitoring

    Normally the dose to the vicinity of the eye is received by the occupational radiation workers who handle radioisotopes or doctors who perform interventional radiographic procedures. The Eye dosimeters provide an estimate of the radiation dose to the lens of the eye. In the recent ICRP-2011 recommendations, the equivalent dose limit for the lens of the eye has been reduced from 150 mSv in a year to 20 mSv in a year for all the occupational workers. To ensure that the dose limit for the eye lens does not exceed the prescribed dose limits, various eye lens dosimeters have been designed and are being used internationally. All these eye dosimeters consist of one natural LiF based thermoluminescence dosimeter (TLD) element sealed in a plastic holder. The design of the eye dosimeter and place of wear (near the eye) plays an important role in correct estimation of the dose to the lens of the eye. It is generally seen that the eye dosimeter when worn with the head strap on the forehead near the eye, the dose the element receives can be easily correlated to the eye dose. This paper presents the design of a new Eye lens dosimeter based on optically stimulated luminescence (OSL) detectors for its possible use by the occupational workers covering the medical, industrial and nuclear facilities for assessing the Hp(3)

  12. Acoustic control in enclosures using optimally designed Helmholtz resonators

    Driesch, Patricia Lynne

    A virtual design methodology is developed to minimize the noise in enclosures with optimally designed, passive, acoustic absorbers (Helmholtz resonators). A series expansion of eigen functions is used to represent the acoustic absorbers as external volume velocities, eliminating the need for a solution of large matrix eigen value problems. A determination of this type (efficient model/reevaluation approach) significantly increases the design possibilities when optimization techniques are implemented. As a benchmarking exercise, this novel methodology was experimentally validated for a narrowband acoustic assessment of two optimally designed Helmholtz resonators coupled to a 2D enclosure. The resonators were tuned to the two lowest resonance frequencies of a 30.5 by 40.6 by 2.5 cm (12 x 16 x 1 inch) cavity with the resonator volume occupying only 2% of the enclosure volume. A maximum potential energy reduction of 12.4 dB was obtained at the second resonance of the cavity. As a full-scale demonstration of the efficacy of the proposed design method, the acoustic response from 90--190 Hz of a John Deere 7000 Ten series tractor cabin was investigated. The lowest cabin mode, referred to as a "boom" mode, proposes a significant challenge to a noise control engineer since its anti-node is located near the head of the operator and often generates unacceptable sound pressure levels. Exploiting the low frequency capability of Helmholtz resonators, lumped parameter models of these resonators were coupled to the enclosure via an experimentally determined acoustic model of the tractor cabin. The virtual design methodology uses gradient optimization techniques as a post processor for the modeling and analysis of the unmodified acoustic interior to determine optimal resonator characteristics. Using two optimally designed Helmholtz resonators; potential energy was experimentally reduced by 3.4 and 10.3 dB at 117 and 167 Hz, respectively.

  13. Acoustics

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  14. Acoustic design and research on the auditorium of Shanghai Grand Theatre

    ZHANG Kuisheng

    2000-01-01

    Shanghai Grand Theatre is a great modern theatre with the largest formula, the highest investment, the most advanced technique and excellent acoustic quality in China. This article mainly introduced Shanghai Grand Theatre's characteristics of formula, technical requirements of acoustic design of Auditorium, characteristics of figure design, reverberation control, acoustic simulation research, acoustic performance and subjective evaluation.

  15. Acoustic design of open plan schools and comparison of requirements

    Møller Petersen, Claus; Rasmussen, Birgit

    2012-01-01

    In the Nordic countries several new schools have open plan areas for teaching and group work. However, to optimize learning efficiency for pupils and working conditions for teachers and to reduce noise levels, such spaces require special acoustic design to obtain sufficient sound attenuation...... between groups and satisfac¬tory speech intelligibility internally in groups. This paper describes the newest Danish requirements and recommendations for such open plan areas and presents the design, measurements and subjective evaluation of two newer Danish schools. According to the users, the general...... conditions at both schools are satisfactory due to both optimized acoustical conditions and teaching methods adapted to the special open environment. The results from room acoustical modelling, verification measurements and questionnaire survey are presented and evaluated in relation to the newest Danish...

  16. International Space Station Crew Quarters Ventilation and Acoustic Design Implementation

    Broyan, James L., Jr.; Cady, Scott M; Welsh, David A.

    2010-01-01

    The International Space Station (ISS) United States Operational Segment has four permanent rack sized ISS Crew Quarters (CQs) providing a private crew member space. The CQs use Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air-from the ISS Common Cabin Air Assembly (CCAA) or the ISS fluid cooling loop. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crew member's head position and reduce acoustic exposure. The CQ ventilation ducts are conduits to the louder Node 2 cabin aisle way which required significant acoustic mitigation controls. The CQ interior needs to be below noise criteria curve 40 (NC-40). The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. Each CQ required 13% of its total volume and approximately 6% of its total mass to reduce acoustic noise. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

  17. Spatial filter lens design for the main laser of the National Ignition Facility

    The National Ignition Facility (NIF), being designed and constructed at Lawrence Livermore National Laboratory (LLNL), comprises 192 laser beams The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1 053microm Sum frequency generation in a pair of conversion crystals (KDP/KD*P) will produce 1 8 megajoules of the third harmonic light (3ω or λ=351microm) at the target The purpose of this paper is to provide the lens design community with the current lens design details of the large optics in the Main Laser This paper describes the lens design configuration and design considerations of the Main Laser The Main Laser is 123 meters long and includes two spatial filters one 13 5 meters and one 60 meters These spatial filters perform crucial beam filtering and relaying functions We shall describe the significant lens design aspects of these spatial filter lenses which allow them to successfully deliver the appropriate beam characteristic onto the target For an overview of NIF please see ''Optical system design of the National Ignition Facility,'' by R Edward English. et al also found in this volume

  18. Design and fabrication of concave-convex lens for head mounted virtual reality 3D glasses

    Deng, Zhaoyang; Cheng, Dewen; Hu, Yuan; Huang, Yifan; Wang, Yongtian

    2015-08-01

    As a kind of light-weighted and convenient tool to achieve stereoscopic vision, virtual reality glasses are gaining more popularity nowadays. For these glasses, molded plastic lenses are often adopted to handle both the imaging property and the cost of massive production. However, the as-built performance of the glass depends on both the optical design and the injection molding process, and maintaining the profile of the lens during injection molding process presents particular challenges. In this paper, optical design is combined with processing simulation analysis to obtain a design result suitable for injection molding. Based on the design and analysis results, different experiments are done using high-quality equipment to optimize the process parameters of injection molding. Finally, a single concave-convex lens is designed with a field-of-view of 90° for the virtual reality 3D glasses. The as-built profile error of the glass lens is controlled within 5μm, which indicates that the designed shape of the lens is fairly realized and the designed optical performance can thus be achieved.

  19. Acoustic lenses

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  20. Design and Optimization of Fresnel Lens for High Concentration Photovoltaic System

    Lei Jing

    2014-01-01

    Full Text Available A practical optimization design is proposed, in which the solar direct light spectrum and multijunction cell response range are taken into account in combination, particularly for the Fresnel concentrators with a high concentration and a small aspect ratio. In addition, the change of refractive index due to temperature variation in outdoor operation conditions is also considered in the design stage. The calculation results show that this novel Fresnel lens achieves an enhancement of energy efficiency of about 10% compared with conventional Fresnel lens for a given solar spectrum, solar cell response, and corrected sunshine hours of different ambient temperature intervals.

  1. Acoustic design criteria in a general system for structural optimization

    Brama, Torsten

    1990-01-01

    Passenger comfort is of great importance in most transport vehicles. For instance, in the new generation of regional turboprop aircraft, a low noise level is vital to be competitive on the market. The possibilities to predict noise levels analytically has improved rapidly in recent years. This will make it possible to take acoustic design criteria into account in early project stages. The development of the ASKA FE-system to include also acoustic analysis has been carried out at Saab Aircraft Division and the Aeronautical Research Institute of Sweden in a joint project. New finite elements have been developed to model the free fluid, porous damping materials, and the interaction between the fluid and structural degrees of freedom. The FE approach to the acoustic analysis is best suited for lower frequencies up to a few hundred Hz. For accurate analysis of interior cabin noise, large 3-D FE-models are built, but 2-D models are also considered to be useful for parametric studies and optimization. The interest is here focused on the introduction of an acoustic design criteria in the general structural optimization system OPTSYS available at the Saab Aircraft Division. The first implementation addresses a somewhat limited class of problems. The problems solved are formulated: Minimize the structural weight by modifying the dimensions of the structure while keeping the noise level in the cavity and other structural design criteria within specified limits.

  2. Design of an acoustic telemetry system for rebreathers.

    Egi, S M

    2009-01-01

    Despite the abundance of telemetric applications for ecology, behavior and physiology of marine life, few efforts were reported about the use of acoustic telemetry for SCUBA divers. The objective of this study is to design and test an acoustic telemetry system for monitoring breathing gases of a Dräger Dolphin semi-closed circuit rebreather as well as the depth of the diver. The system is designed around a PC based surface unit and a microcontroller based diver carried module that digitizes the output of CO2 and O2 sensors located in the inhalation side of the canister. One pair of acoustic modems establishes the data link between the microcontroller and the topside PC. The graphical user interface is written in C# and enables the recording of the diving session as well. The system is calibrated in a hyperbaric chamber and tested successfully with four dives in three different environments using 100% O2 and Nitrox (47.9% O2 - 52.1% N2) up to 15 m depth and a distance of 40 m between acoustic modems. The telemetry data cannot be used only for recording physiological data but also provides an important operational safety tool to monitor the rebreather user. The future designs will include actuators for controlling the diluent and oxygen flow to closed circuit mix gas rebreathers. PMID:19341129

  3. The design and application of large area intensive lens array focal spots measurement system

    Chen, Bingzhen; Yao, Shun; Yang, Guanghui; Dai, Mingchong; Wang, Zhiyong

    2014-12-01

    Concentrating Photovoltaic (CPV) modules are getting thinner and using smaller cells now days. Correspondingly, large area intensive lens arrays with smaller unit dimension and shorter focal length are wanted. However, the size and power center of lens array focal spots usually differ from the design value and are hard to measure, especially under large area situation. It is because the machining error and deformation of material of the lens array are hard to simulate in the optical design process. Thus the alignment error between solar cells and focal spots in the module assembly process will be hard to control. Under this kind of situation, the efficiency of CPV module with thinner body and smaller cells is much lower than expected. In this paper, a design of large area lens array focal spots automatic measurement system is presented, as well as its prototype application results. In this system, a four-channel parallel light path and its corresponding image capture and process modules are designed. These modules can simulate focal spots under sunlight and have the spots image captured and processed using charge coupled devices and certain gray level algorithm. Thus the important information of focal spots such as spot size and location will be exported. Motion control module based on grating scale signal and interval measurement method are also employed in this system in order to get test results with high speed and high precision on large area lens array no less than 1m×0.8m. The repeatability of the system prototype measurement is +/-10μm with a velocity of 90 spot/min. Compared to the original module assembled using coordinates from optical design, modules assembled using data exported from the prototype is 18% higher in output power, reaching a conversion efficiency of over 31%. This system and its design can be used in the focal spot measurement of planoconvex lens array and Fresnel lens array, as well as other kinds of large area lens array application

  4. Active acoustic metamaterials reconfigurable in real-time

    Popa, Bogdan-Ioan; Konneker, Adam; Cummer, Steven A

    2015-01-01

    A major limitation of current acoustic metamaterials is that their acoustic properties are either locked into place once fabricated or only modestly tunable, tying them to the particular application for which they are designed. We present in this paper a design approach that yields active metamaterials whose physical structure is fixed, yet their local acoustic response can be changed almost arbitrarily and in real-time by configuring the digital electronics that control the metamaterial acoustic properties. We demonstrate experimentally this approach by designing a metamaterial slab configured to act as a very thin acoustic lens that manipulates differently three identical, consecutive pulses incident on the lens. Moreover, we show that the slab can be configured to implement simultaneously various roles, such as that of a lens and beam steering device. Finally, we show that the metamaterial slab is suitable for efficient second harmonic acoustic imaging devices capable to overcome the diffraction limit of l...

  5. Acoustic Design of Super-light Structures

    Christensen, Jacob Ellehauge; Hertz, Kristian Dahl; Brunskog, Jonas;

    Super-light structures is a newly developed and patented construction principle for concrete structures. It combines some of the desirable properties of normal strong concrete and lightweight aggregate concrete in order to improve the utilization of the materials and to design improved concrete...... structures and elements. The super-light slab element in the present research is developed as a holistic design including all relevant disciplines. The element is based on wellknown technologies and materials, which have been used for millenniums, namely compression arches and lightweight expanded clay...

  6. Design and position control of AF lens actuator for mobile phone using IPMC-EMIM

    Kim, Sung-Joo; Kim, Chul-Jin; Park, No-Cheol; Yang, Hyun-Seok; Park, Young-Pil; Park, Kang-Ho; Lee, Hyung-Kun; Choi, Nak-Jin

    2008-03-01

    IPMC-EMIM (Ionic Polyer Metal Composites + 1-ethyl-3- methyl imidazolium trifluromethane sulfonate, EMIM-Tfo) is fabricated by substituting ionic liquid for water in Nafion film, which improves water sensitiveness of IPMC and guarantees uniform performance regardless of the surrounding environment. In this paper, we will briefly introduce the procedure of fabrication of IPMC-EMIM and proceed to introduce the Hook-type actuator using IPMC-EMIM and application to AF Lens actuator. Parameters of Hook-type actuator are estimated from experimental data. In the simulation, The proposed AF Lens Actuator is assumed to be a linear system and based on estimated parameters, PID controller will be designed and controlled motion of AF Lens actuator will be shown through simulation.

  7. "METHOD": A tool for mechanical, electrical, thermal, and optical characterization of single lens module design

    Besson, Pierre; Dominguez, Cesar; Voarino, Philippe; Garcia-Linares, Pablo; Weick, Clement; Lemiti, Mustapha; Baudrit, Mathieu

    2015-09-01

    The optical characterization and electrical performance evaluation are essential in the design and optimization of a concentrator photovoltaic system. The geometry, materials, and size of concentrator optics are diverse and different environmental conditions impact their performance. CEA has developed a new concentrator photovoltaic system characterization bench, METHOD, which enables multi-physics optimization studies. The lens and cell temperatures are controlled independently with the METHOD to study their isolated effects on the electrical and optical performance of the system. These influences can be studied in terms of their effect on optical efficiency, focal distance, spectral sensitivity, electrical efficiency, or cell current matching. Furthermore, the irradiance map of a concentrator optic can be mapped to study its variations versus the focal length or the lens temperature. The present work shows this application to analyze the performance of a Fresnel lens linking temperature to optical and electrical performance.

  8. Design and Construction of Solenoid Magnetic Lens for Focusing Electron Beam from Thermionic Electron Gun

    Electron gun is an important part of an electron accelerator for producing electron beam to be irradiated on material. The electron gun of electron accelerator constructed at P3TM BATAN, is a thermionic electron gun, A solenoid magnetic lens had been designed and constructed for focusing electron beam extracted from the electron gun in such away that all of the electron beam enter the accelerating tube. Technical specification of the solenoid magnetic lens is given in this paper. Measurement of magnetic field generated by solenoid coil shows that the largest magnetic field is in the middle of the solenoid coil. The test using the thermionic electron gun shows the focusing effect on electron beam by the solenoid magnetic lens. The focus strength is maximum after the coil current reaches 9 A. (author)

  9. Design Research through the Lens of Sociology of Technology

    Berntsen, Hilde Østerås; Seim, Rikke

    2007-01-01

    processes by viewing these processes as building and alignment of networks. The applicability of ANT in design research is demonstrated in an analysis of an action research based case study. In this case study a socio-technical approach called “workspace design” is employed in a process of re-design of......The use of an approach to design research inspired by Sociology of Technology offers a nuanced understanding of design processes. The purpose of this paper is to explore how terminology derived from the socio-technical theory of Actor Network (ANT) can be used to understand the complexity of design...... existing workspace and work practice in an industrial company. The case study (i) illustrates a socio-technical approach to design research and (ii) shows how ANT terminology can be applied in an analysis of the course of events in a design process with numerous actors involved....

  10. Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

    Thomas J. Carlson

    2012-07-01

    Full Text Available PZT ceramics have been widely used in underwater acoustic transducers. However, literature available discussing the design parameters of a miniaturized PZT-based low-duty-cycle transmitter is very limited. This paper discusses some of the design parameters—the backing material, driving voltage, PZT material type, power consumption and the transducer length of a miniaturized acoustic fish tag using a PZT tube. Four different types of PZT were evaluated with respect to the source level, energy consumption and bandwidth of the transducer. The effect of the tube length on the source level is discussed. The results demonstrate that ultralow-density closed-cell foam is the best backing material for the PZT tube. The Navy Type VI PZTs provide the best source level with relatively low energy consumption and that a low transducer capacitance is preferred for high efficiency. A 35% reduction in the transducer length results in 2 dB decrease in source level.

  11. Design parameters of a miniaturized piezoelectric underwater acoustic transmitter.

    Li, Huidong; Deng, Zhiqun Daniel; Yuan, Yong; Carlson, Thomas J

    2012-01-01

    PZT ceramics have been widely used in underwater acoustic transducers. However, literature available discussing the design parameters of a miniaturized PZT-based low-duty-cycle transmitter is very limited. This paper discusses some of the design parameters--the backing material, driving voltage, PZT material type, power consumption and the transducer length of a miniaturized acoustic fish tag using a PZT tube. Four different types of PZT were evaluated with respect to the source level, energy consumption and bandwidth of the transducer. The effect of the tube length on the source level is discussed. The results demonstrate that ultralow-density closed-cell foam is the best backing material for the PZT tube. The Navy Type VI PZTs provide the best source level with relatively low energy consumption and that a low transducer capacitance is preferred for high efficiency. A 35% reduction in the transducer length results in 2 dB decrease in source level. PMID:23012534

  12. Acoustic design of rotor blades using a genetic algorithm

    Wells, V. L.; Han, A. Y.; Crossley, W. A.

    1995-01-01

    A genetic algorithm coupled with a simplified acoustic analysis was used to generate low-noise rotor blade designs. The model includes thickness, steady loading and blade-vortex interaction noise estimates. The paper presents solutions for several variations in the fitness function, including thickness noise only, loading noise only, and combinations of the noise types. Preliminary results indicate that the analysis provides reasonable assessments of the noise produced, and that genetic algorithm successfully searches for 'good' designs. The results show that, for a given required thrust coefficient, proper blade design can noticeably reduce the noise produced at some expense to the power requirements.

  13. Circuit Design of Surface Acoustic Wave Based Micro Force Sensor

    Yuanyuan Li

    2014-01-01

    Full Text Available Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established to analyze the frequency, and a peripheral circuit is designed to measure the micro force. The SAW based micro force sensor is tested to show the reasonable design of detection circuit and the stability of frequency and amplitude.

  14. Integrating acoustic analysis in the architectural design process using parametric modelling

    Peters, Brady

    2011-01-01

    This paper discusses how parametric modeling techniques can be used to provide architectural designers with a better understanding of the acoustic performance of their designs and provide acoustic engineers with models that can be analyzed using computational acoustic analysis software. Architects...... parametric modeling, acoustic performance can inform the geometry and material logic of the design. In this way, the architectural design and the acoustic analysis model become linked........ This can provide a method by which architects and engineers can work together more efficiently and communicate better. This research is illustrated through the design of an architectural project, a new school in Copenhagen, Denmark by JJW Architects, where parametric modeling techniques have been used...

  15. Conceptual design study of a 5 kilowatt solar dynamic Brayton power system using a dome Fresnel lens solar concentrator

    Oneill, Mark J.; Mcdanal, A. J.; Spears, Don H.

    1989-01-01

    The primary project objective was to generate a conceptual design for a nominal 5 kW solar dynamic space power system, which uses a unique, patented, transmittance-optimized, dome-shaped, point-focus Fresnel lens as the optical concentrator. Compared to reflective concentrators, the dome lens allows 200 times larger slope errors for the same image displacement. Additionally, the dome lens allows the energy receiver, the power conversion unit (PCU), and the heat rejection radiator to be independently optimized in configuration and orientation, since none of these elements causes any aperture blockage. Based on optical and thermal trade studies, a 6.6 m diameter lens with a focal length of 7.2 m was selected. This lens should provide 87 percent net optical efficienty at 800X geometric concentration ratio. The large lens is comprised of 24 gores, which compactly stow together during launch, and automatically deploy on orbit. The total mass of the microglass lens panels, the graphite/epoxy support structure, and miscellaneous hardware is about 1.2 kg per square meter of aperture. The key problem for the dome lens approach relates to the selection of a space-durable lens material. For the first time, all-glass Fresnel lens samples were successfully made by a sol-gel casting process.

  16. Design and Optimization of Fresnel Lens for High Concentration Photovoltaic System

    Lei Jing; Hua Liu; Yao Wang; Wenbin Xu; Hongxin Zhang; Zhenwu Lu

    2014-01-01

    A practical optimization design is proposed, in which the solar direct light spectrum and multijunction cell response range are taken into account in combination, particularly for the Fresnel concentrators with a high concentration and a small aspect ratio. In addition, the change of refractive index due to temperature variation in outdoor operation conditions is also considered in the design stage. The calculation results show that this novel Fresnel lens achieves an enhancement of energy ef...

  17. Optical design of the Fresnel lens for LED-driven flashlight.

    Chen, Yi-Cheng; Nian, Shih-Chih; Huang, Ming-Shyan

    2016-02-01

    The Fresnel lens is composed of micrometer-sized v-groove structures that determine the maximum illuminance and brightness uniformity of LED-driven flashlights, which are used in high-quality photography. The fabrication quality of the microstructures and the accuracy of the geometrical curvature of the Fresnel lens affect the optical characteristics of the emitted light traveling through the lens, which in turn determines the maximum illuminance and brightness uniformity. This paper presents a systematic design procedure for fabricating the Fresnel lens and investigates the influence of geometrical design and fabrication process on optical performance. The optical analysis was performed using the commercial software TracePro. The results revealed that a small tip radius of the v-groove microstructure facilitates brightness uniformity. Furthermore, both the simulation and the experimental results revealed that Fresnel lenses fabricated through injection molding or injection compression molding have either errors of microstructure height more than 3%-6% or curvature errors higher than 6%, which would affect the optical performance, especially the brightness uniformity. PMID:26836072

  18. Mechanical design of a power-adjustable spectacle lens frame

    Zapata, Asunción; Barbero, Sergio

    2011-01-01

    Power-adjustable spectacle lenses, based on the Alvarez–Lohmann principle, can be used to provide affordable spectacles for subjective refractive errors measurement and its correction. A new mechanical frame has been designed to maximize the advantages of this technology. The design includes a mechanism to match the interpupillary distance with that of the optical centers of the lenses. The frame can be manufactured using low cost plastic injection molding techniques. A prototype ...

  19. Free-form thin lens design with light scattering surfaces for practical LED down light illumination

    Lin, Raychiy J.; Sun, Ching-Cherng

    2016-05-01

    The free-form optical quasilens surface technology was utilized to develop and design a solid transparent plastic optical lens for the LED down light with the narrow angular light distribution requirement in the LED lighting applications. In order to successfully complete the mission, the precise mid-field angular distribution model of the LED light source was established and built. And also the optical scattering surface property of the Harvey BSDF scattering model was designed, measured, and established. Then, the optical simulation for the entire optical system was performed to develop and design this solid transparent plastic optical lens system. Finally, the goals of 40 deg angular light distribution pattern defined at full width half maximum with glare reduced in the areas of interest and the optical performance of nearly 82% light energy transmission optics were achieved for the LED down light illumination.

  20. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). PMID:27294937

  1. Harnessing buckling to design tunable locally resonant acoustic metamaterials.

    Wang, Pai; Casadei, Filippo; Shan, Sicong; Weaver, James C; Bertoldi, Katia

    2014-07-01

    We report a new class of tunable and switchable acoustic metamaterials comprising resonating units dispersed into an elastic matrix. Each resonator consists of a metallic core connected to the elastomeric matrix through elastic beams, whose buckling is intentionally exploited as a novel and effective approach to control the propagation of elastic waves. We first use numerical analysis to show the evolution of the locally resonant band gap, fully accounting for the effect of nonlinear pre-deformation. Then, we experimentally measure the transmission of vibrations as a function of the applied loading in a finite-size sample and find excellent agreement with our numerical predictions. The proposed concept expands the ability of existing acoustic metamaterials by enabling tunability over a wide range of frequencies. Furthermore, we demonstrate that in our system the deformation can be exploited to turn on or off the band gap, opening avenues for the design of adaptive switches. PMID:25032927

  2. Design and Development of Binary Diffractive Germanium Lens by Thin Film Deposition

    Alshami, M.; Wabby, A.; Mousselly, M. F.

    2015-11-01

    The design and development of infrared (λ: [8]-[12] μm) binary diffractive germanium lens (BDGL) by two - steps thin film deposition (Physical vapor deposition (PVD) technique) is presented. The optical design of the required elements using the optical design code Zemax, the design of the 4 steps binary surface and its required metallic masks using the programming language Delphi, the procedures of fabrication, and the measurement of the resulting profile, were presented. The comparison between the refractive/diffractive lenses by measuring the minimum resolvable temperature difference (MRTD) shows the advantages of binary diffractive surface.

  3. FEA Analysis of AP-0 Target Hall Collection Lens (Current Design)

    The AP-0 Target Hall Collection Lens is a pulsed device which focuses anti-protons just downstream of the Target. Since the angles at which the anti-protons depart the Target can be quite large, a very high focusing strength is required to maximize anti-proton capture into the downstream Debuncher Ring. The current design of the Collection Lens was designed to operate with a focusing gradient of 1,000 T/m. However, multiple failures of early devices resulted in lowering the normal operating gradient to about 750 T/m. At this gradient, the Lens design fares much better, lasting several million pulses, but ultimately still fails. A Finite Element Analysis (FEA) has been performed on this Collection Lens design to help determine the cause and/or nature of the failures. The Collection Lens magnetic field is created by passing high current through a central conductor cylinder. A uniform current distribution through the cylinder will create a tangential or azimuthal magnetic field that varies linearly from zero at the center of the cylinder to a maximum at the outer surface of the cylinder. Anti-proton particles passing through this cylinder (along the longitudinal direction) will see an inward focusing kick back toward the center of the cylinder proportional to the magnetic field strength. For the current Lens design a gradient of 1,000 T/m requires a current of about 580,000 amps. Since the DC power and cooling requirements would be prohibitive, the Lens is operated in a pulsed mode. Each pulse is half sine wave in shape with a pulse duration of about 350 microseconds. Because of the skin effect, the most uniform current density actually occurs about two-thirds of the way through the pulse. This means that the maximum current of the pulse is actually higher than that required in the DC case (about 670,000 amps). Since the beam must pass through the central conductor cylinder it must be made of a conducting material that is also very 'transparent' to the beam. For the

  4. SILICON COMPATIBLE ACOUSTIC WAVE RESONATORS: DESIGN, FABRICATION AND PERFORMANCE

    Aliza Aini Md Ralib

    2014-12-01

    Full Text Available ABSTRACT: Continuous advancement in wireless technology and silicon microfabrication has fueled exciting growth in wireless products. The bulky size of discrete vibrating mechanical devices such as quartz crystals and surface acoustic wave resonators impedes the ultimate miniaturization of single-chip transceivers. Fabrication of acoustic wave resonators on silicon allows complete integration of a resonator with its accompanying circuitry.  Integration leads to enhanced performance, better functionality with reduced cost at large volume production. This paper compiles the state-of-the-art technology of silicon compatible acoustic resonators, which can be integrated with interface circuitry. Typical acoustic wave resonators are surface acoustic wave (SAW and bulk acoustic wave (BAW resonators.  Performance of the resonator is measured in terms of quality factor, resonance frequency and insertion loss. Selection of appropriate piezoelectric material is significant to ensure sufficient electromechanical coupling coefficient is produced to reduce the insertion loss. The insulating passive SiO2 layer acts as a low loss material and aims to increase the quality factor and temperature stability of the design. The integration technique also is influenced by the fabrication process and packaging.  Packageless structure using AlN as the additional isolation layer is proposed to protect the SAW device from the environment for high reliability. Advancement in miniaturization technology of silicon compatible acoustic wave resonators to realize a single chip transceiver system is still needed. ABSTRAK: Kemajuan yang berterusan dalam teknologi tanpa wayar dan silikon telah menguatkan pertumbuhan yang menarik dalam produk tanpa wayar. Saiz yang besar bagi peralatan mekanikal bergetar seperti kristal kuarza menghalang pengecilan untuk merealisasikan peranti cip. Silikon serasi  gelombang akustik resonator mempunyai potensi yang besar untuk menggantikan unsur

  5. Wavenumber transform analysis for acoustic black hole design.

    Feurtado, Philip A; Conlon, Stephen C

    2016-07-01

    Acoustic black holes (ABHs) are effective, passive, lightweight vibration absorbers that have been developed and shown to effectively reduce the structural vibration and radiated sound of beam and plate structures. ABHs employ a local thickness change that reduces the speed of bending waves and increases the transverse vibration amplitude. The vibrational energy can then be effectively focused and dissipated by material losses or through conventional viscoelastic damping treatments. In this work, the measured vibratory response of embedded ABH plates was transformed into the wavenumber domain in order to investigate the use of wavenumber analysis for characterizing, designing, and optimizing practical ABH systems. The results showed that wavenumber transform analysis can be used to simultaneously visualize multiple aspects of ABH performance including changes in bending wave speed, transverse vibration amplitude, and energy dissipation. The analysis was also used to investigate the structural acoustic coupling of the ABH system and determine the radiation efficiency of the embedded ABH plates compared to a uniform plate. The results demonstrated that the ABH effect results in acoustic decoupling as well as vibration reduction. The wavenumber transform based methods and results will be useful for implementing ABHs into real world structures. PMID:27475193

  6. Design and optimization of multipole lens and Wien filter systems

    The differential algebra (DA) method has been employed to compute the optical properties and aberrations up to the fifth order of multipole systems containing electrostatic and magnetic round, quadrupole, hexapole and octopole lenses, and Wien filters. A new software package has been developed, which computes the geometrical and chromatic aberrations up to the fifth order by using a single DA ray trace. It also has an optimization module where a weighted set of aberrations can be minimized by the automatic adjustment of a set of user-defined system variables. In this paper, we present our new method for designing and optimizing multipole systems including Wien filters, and illustrate its application with three relevant examples.

  7. Three-dimensional ultrathin planar lenses by acoustic metamaterials.

    Li, Yong; Yu, Gaokun; Liang, Bin; Zou, Xinye; Li, Guangyun; Cheng, Su; Cheng, Jianchun

    2014-01-01

    Acoustic lenses find applications in various areas ranging from ultrasound imaging to nondestructive testing. A compact-size and high-efficient planar acoustic lens is crucial to achieving miniaturization and integration, and should have deep implication for the acoustic field. However its realization remains challenging due to the trade-off between high refractive-index and impedance-mismatch. Here we have designed and experimentally realized the first ultrathin planar acoustic lens capable of steering the convergence of acoustic waves in three-dimensional space. A theoretical approach is developed to analytically describe the proposed metamaterial with hybrid labyrinthine units, which reveals the mechanism of coexistence of high refractive index and well-matched impedance. A hyperbolic gradient-index lens design is fabricated and characterized, which can enhance the acoustic energy by 15 dB at the focal point with very high transmission efficiency. Remarkably, the thickness of the lens is only approximately 1/6 of the operating wavelength. The lens can work within a certain frequency band for which the ratio between the bandwidth and the center frequency reaches 0.74. By tailoring the structure of the metamaterials, one can further reduce the thickness of the lens or even realize other acoustic functionalities, opening new opportunity for manipulation of low-frequency sounds with versatile potential. PMID:25354997

  8. Design of a compact focusing lens system with short acceleration tube at 300 kV

    A compact focusing lens system with high demagnification over 1500 was designed to form an ion nanobeam with 346 keV energy by adding a short distance acceleration tube for beam acceleration and focusing downstream of the existing double acceleration lens system. The demagnification, focusing points and aberrations of the acceleration tube were studied using beam trajectory calculation. The acceleration tube was designed to have a length of 140 mm and a demagnification of 2 at its acceleration tube voltage of 300 kV, which resulted in a new compact focusing lens system with a total length of about 640 mm. In addition, the maximum voltage and electric-field of the acceleration tube were confirmed experimentally on the built device to be 300 kV and 30 kV/cm, respectively. The final beam size formed by the system was estimated to be 130 nm in diameter using the design parameters. The result suggests that an ion nanobeam of 346 keV can be formed by an apparatus having the reasonable length of 2 m, which permits us to develop a system for 1 MV by elongating its tube length.

  9. Optical system design for lens with large relative aperture

    Zhang, Kaisheng; Zhang, Zhi; Zhang, Zhaohui; Wang, Zefeng; Yan, Aqi; Fei, Jiaqi; Mei, Chao; Zhang, Gaopeng

    2015-10-01

    As the space remote sensing technology progresses, the developing trend of telescope is larger and larger aperture, higher and higher resolution. An Optical system with the relative aperture of 1:2 is introduced. The primary optical properties are: focal length of 120mm, F number of 2, field angle of 7.4°. It has the advantages of large high resolution, small size and excellent image quality. Several kinds of aberration curves and the MTF curve are given. Its imaging quality is nearly diffraction limited so that the spatial frequency is greater than 70lp/mm when its modulated transfer function (MTF) value of the optical system is equal to 0.8,and the optical system distortion is less than 1%. At last, the stray light is analyzed and the baffle of the telescope is designed. The solid model of the Optical system was constructed in Tracepro software, the point sources transmittance (PST) cure was given at different off-axis angle between 7.4°~80° the analysis result indicates that the PST values are less than 10-6 when off-axis angle are larger than soar critical angle. So the system is suitable for observation or photography of deep sky objects.

  10. Design of compact freeform lens for application specific Light-Emitting Diode packaging.

    Wang, Kai; Chen, Fei; Liu, Zongyuan; Luo, Xiaobing; Liu, Sheng

    2010-01-18

    Application specific LED packaging (ASLP) is an emerging technology for high performance LED lighting. We introduced a practical design method of compact freeform lens for extended sources used in ASLP. A new ASLP for road lighting was successfully obtained by integrating a polycarbonate compact freeform lens of small form factor with traditional LED packaging. Optical performance of the ASLP was investigated by both numerical simulation based on Monte Carlo ray tracing method and experiments. Results demonstrated that, comparing with traditional LED module integrated with secondary optics, the ASLP had advantages of much smaller size in volume (approximately 1/8), higher system lumen efficiency (approximately 8.1%), lower cost and more convenience for customers to design and assembly, enabling possible much wider applications of LED for general road lighting. Tolerance analyses were also conducted. Installation errors of horizontal and vertical deviations had more effects on the shape and uniformity of radiation pattern compared with rotational deviation. The tolerances of horizontal, vertical and rotational deviations of this lens were 0.11 mm, 0.14 mm and 2.4 degrees respectively, which were acceptable in engineering. PMID:20173861

  11. New tools for finding first-order zoom lens solutions and the analysis of zoom lenses during the design process

    Yee, Anthony J.; Williams, Daniel J. L.; Gandara-Montano, Gustavo A.; McCarthy, Peter; Bentley, Julie; Moore, Duncan T.

    2015-09-01

    We developed software design tools in MATLAB that are compatible with Code V for supporting the process of designing zoom lenses. These tools simplify the process of finding paraxial solutions and evaluating intermediary design steps. Paraxial solutions are found through a partially random search for four group zoom systems with moving second and third groups. It requires several user-specified system parameters and then randomly assigns powers to each group. This process of randomly assigning powers is done a set number of times and only the valid solutions where no lenses crash are considered for further use. The valid designs are plotted over different design criteria and can then be selected to retrieve the first order design parameters. For the intermediate design process, the software displays lens specifications and diagnostic results across zoom for the entire lens as well as the individual groups. Systematic evaluation of the intermediate design steps is useful in determining how to proceed and improve the design. The design process is described for two different zoom lenses to show the efficiency and utility of these tools. The two zoom lenses are a 16x surveillance camera zoom lens working in the visible and a 3X zoom lens working in the visible and short wave infrared. The design procedure for these lenses covers finding the paraxial solutions to evaluating the lens for further improvement.

  12. Designable hybrid sonic crystals for transportation and division of acoustic images

    He, Zhaojian; Deng, Ke; Zhao, Heping; Li, Xiaochun

    2012-01-01

    Conventional sonic crystal (SC) devices designed for acoustic imaging can focus acoustic waves from an input source into only one image but not multi-images. Furthermore the output position of formed image cannot be designed at will. In this paper, we propose the hybrid SC imaging devices to achieve multi-images from one-source-input along with the designable image-positions. The proposed hybrid devices can image acoustic waves radiated both from point source and Gaussian beam, which differen...

  13. Data analysis results of the second sea trial of ambient noise imaging with acoustic lens in 2014: Two-dimensional target images affected by direction of field of view and spatial noise distribution

    Mori, Kazuyoshi; Ogasawara, Hanako; Tsuchiya, Takenobu; Endoh, Nobuyuki

    2016-07-01

    An aspherical lens with an aperture diameter of 1.0 m has been designed and fabricated to develop a prototype system for ambient noise imaging (ANI). A sea trial of silent target detection using the prototype ANI system was conducted under only natural ocean ambient noise at Uchiura Bay in November 2010. It was verified that targets are successfully detected under natural ocean ambient noise, mainly generated by snapping shrimps. Recently, we have built a second prototype ANI system using an acoustic lens with a two-dimensional (2D) receiver array with 127 elements corresponding to a field of view (FOV) spanning 15° horizontally by 9° vertically. In this study, we investigated the effects of the direction of the FOV and the spatial noise distribution on the 2D target image obtained by ANI. Here, the noise sources in front of the target are called “front light”, and those at the rear of the target are called “back light”. The second sea trial was conducted to image targets arranged in the FOV and measure the positions of noise sources at Uchiura Bay in November 10–14, 2014. For front light, the pixel values in the on-target directions were greater than those in other directions owing to the dominant target scatterings. Reversely, for back light, the pixel values in the on-target directions were lower than those in other directions owing to the dominant direct noises such as “silhouette”.

  14. Fresnel Lens

    Watson, Michael D.; Scott, Steve; Lamb, David; Zimmerman, Joe E. (Technical Monitor)

    2001-01-01

    Fresnel lenses span the full range of sizes from lens a few micrometers in diameter to lens several meters in diameter. These lenses are utilized in various fields including optical communication, theatrical lighting, office equipment, video entertainment systems, solar concentrators, and scientific research instruments. These lenses function either as diffractive or refractive optical elements depending on the geometrical feature size of the lens. The basic functions of these lenses is described followed by an overview of fabrication methods. A summary of applications is then provided illustrating the rich variety of applications for which fresnel lenses may be designed to fulfill.

  15. Design of crude oil storage tank for acoustic emission testing

    The integrity of crude oil storage tank needs to be well managed because they can contain a large inventory of hazardous material and because of the high cost such as cleaning and waste disposal prior to disposal and maintenance. Costs involved in cleaning and inspection can be up to several hundreds thousand Malaysian Ranting. If the floor then proves to be in good condition, these costs have been wasted. Acoustic Emission (AE) is proposed to be use for monitoring the floor of the storage tank on line without doing cleaning and waste disposal. A storage tank will be fabricated for storing the crude oil and then the corrosion process will be monitor using AE method. This paper will discuss the background, material and is technical specification, design and also the difficulties faced during design and fabrication process. (Author)

  16. Performance of a slow positron beam using a hybrid lens design

    The University of Hong Kong positron beam employs conventional magnetic field transport to the target, but has a special hybrid lens design around the positron moderator that allows the beam to be focused to millimeter spot sizes at the target. The good focusing capabilities of the beam are made possible by extracting work-function positrons from the moderator in a magnetic field free region using a conventional Soa lens thus minimizing beam canonical angular momentum. An Einzel lens is used to focus the positrons into the magnetic funnel at the end of transportation magnetic field while at the same time bringing up the beam energy to the intermediate value of 7.5 keV. The beam is E x B filtered at this intermediate energy. The final beam energy is obtained by floating the Soa-Einzel system, E x B filter and flight tube, and accelerating the positrons just before the target. External beam steering saddle coils fine tune the position, and the magnetic field around the target chamber is adjusted so as to keep one of the beam foci always on the target. The system is fully computer controlled. Variable energy-Doppler broadened annihilation radiation (VEDBAR) data for a GaN sample are shown which demonstrate the performance of the positron beam system

  17. Freeform lens design for providing LED small angle illumination in underwater application

    Zhang, Xiaohui; Chen, Chen

    2015-08-01

    With high light efficiency and long aging life, LED solid-state light source has attracted much attention in underwater application, such as optical communication and imaging. But, the large divergence angle of LED illumination has been a big challenge in practical underwater application, such as the light attenuation in water and then the decreased signal-to-noise ratio. Source-target map is a vital method in illumination optics design, and the focus is to solve numerically differential equations and then construct the freeform surface. To achieve high accuracy freeform surface, an improved method is suggested and optimized through much more advanced and accuracy Runge-Kutta method, which is different from the original design one through Euler method. The designed lens is simulated by ray trace software TracePro, and the simulation results show that the uniformity of 0.8 and the efficacy of 0.6 is obtained. While as, the method is proven to be effective, and also the accuracy of the smooth freeform surface is strengthened. One designed illumination lens is fabricated by computer numeric control (CNC) machine to demonstrate the design experimentally.

  18. Changing space and sound: Parametric design and variable acoustics

    Norton, Christopher William

    This thesis examines the potential for parametric design software to create performance based design using acoustic metrics as the design criteria. A former soundstage at the University of Southern California used by the Thornton School of Music is used as a case study for a multiuse space for orchestral, percussion, master class and recital use. The criteria used for each programmatic use include reverberation time, bass ratio, and the early energy ratios of the clarity index and objective support. Using a panelized ceiling as a design element to vary the parameters of volume, panel orientation and type of absorptive material, the relationships between these parameters and the design criteria are explored. These relationships and subsequently derived equations are applied to Grasshopper parametric modeling software for Rhino 3D (a NURBS modeling software). Using the target reverberation time and bass ratio for each programmatic use as input for the parametric model, the genomic optimization function of Grasshopper - Galapagos - is run to identify the optimum ceiling geometry and material distribution.

  19. Acoustical Design Guidelines for Living Rooms for Adults with intellectual Disabilities

    Saher, K.

    2013-01-01

    The aim of this thesis is to investigate the effects of building design tools on acoustical quality parameters in living rooms for adults with intellectual disabilities (ID) and develop acoustical design guidelines for architects. This study is specifically concerned with the validation of auralizat

  20. DESIGN OF MODULATION AND COMPRESSION CODING IN UNDERWATER ACOUSTIC IMAGE TRANSMISSION

    程恩; 余丽敏; 林耿超

    2002-01-01

    This paper describes the design of modulation, compression coding and transmissi on control in underwater acoustic color image transmission system. This design adap ts a special system of modulation and transmission control based on a DSP(Digital Signal Processing) chip, to cope with the complex underwater acoustic channel. The hardware block diagram and software flow chart are presented.

  1. DESIGN OF MODULATION AND COMPRESSION CODING IN UNDERWATER ACOUSTIC IMAGE TRANSMISSION

    程恩; 余丽敏; 林耿超

    2002-01-01

    This paper describes the design of modulation, compression coding and transmission control in underwater acoustic color image transmission system. This design adapts a special system of modulation and transmission control based on a DSP(Digital Signal Processing) chip, to cope with the complex underwater acoustic channel. The hardware block diagram and software flow chart are presented.

  2. Intraocular lens design for treating high myopia based on individual eye model

    Wang, Yang; Wang, Zhaoqi; Wang, Yan; Zuo, Tong

    2007-02-01

    In this research, we firstly design the phakic intraocular lens (PIOL) based on individual eye model with optical design software ZEMAX. The individual PIOL is designed to correct the defocus and astigmatism, and then we compare the PIOL power calculated from the individual eye model with that from the experiential formula. Close values of PIOL power are obtained between the individual eye model and the formula, but the suggested method has more accuracy with more functions. The impact of PIOL decentration on human eye is evaluated, including rotation decentration, flat axis decentration, steep axis decentration and axial movement of PIOL, which is impossible with traditional method. To control the PIOL decentration errors, we give the limit values of PIOL decentration for the specific eye in this study.

  3. Active acoustic metamaterials reconfigurable in real time

    Popa, Bogdan-Ioan; Shinde, Durvesh; Konneker, Adam; Cummer, Steven A.

    2015-06-01

    A major limitation of current acoustic metamaterials is that their acoustic properties are either locked into place once fabricated or are only modestly tunable, tying them to the particular application for which they are designed. We present a design approach that yields active metamaterials whose physical structure is fixed, yet their local acoustic response can be changed almost arbitrarily and in real time by configuring the digital electronics that control the metamaterial acoustic properties. We demonstrate this approach experimentally by designing a metamaterial slab configured to act as a very thin acoustic lens that manipulates differently three identical, consecutive pulses incident on the lens. Moreover, we show that the slab can be configured to simultaneously implement various roles, such as that of a lens and a beam steering device. Finally, we show that the metamaterial slab is suitable for efficient second harmonic acoustic imaging devices capable of overcoming the diffraction limit of linear lenses. These advantages demonstrate the versatility of this active metamaterial and highlight its broad applicability, in particular, to acoustic imaging.

  4. Design and development of a high-concentration and high-efficiency photovoltaic concentrator using a curved Fresnel lens

    Scharlack, R.S.; Moffat, A.

    1983-08-01

    Thermo Electron has designed a high concentration photovoltaic module that uses a domed, point-focus Fresnel lens. Their design, design optimization process, and results from lens and receiver tests are described in this report. A complete module has not been fabricated and probably will not be fabricated in the future; however, Thermo Electron's optical design, analysis, and testing of both secondary optical units and domed Fresnel lenses have made a significant contribution to our project. Tooling errors prevented the lens from reaching its potential efficiency by the end of the contract, and resolution of these tooling problems is currently being attempted with a follow-on contract, No. 68-9463.

  5. A study of tailoring acoustic porous material properties when designing lightweight multilayered vehicle panels

    Lind Nordgren, Eleonora

    2012-01-01

    The present work explores the possibilities of adapting poro-elastic lightweight acoustic materials to specific applications. More explicitly, a design approach is presented where finite element based numerical simulations are combined with optimization techniques to improve the dynamic and acoustic properties of lightweight multilayered panels containing poro-elastic acoustic materials. The numerical models are based on Biot theory which uses equivalent fluid/solid models with macroscopic sp...

  6. Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

    CASADEI, FILIPPO; Bertoldi, Katia

    2014-01-01

    The design of phononic crystals and acoustic metamaterials with tunable and adaptive wave properties remains one of the outstanding challenges for the development of next generation acoustic devices. We report on the numerical and experimental demonstration of a locally resonant acoustic metamaterial with dispersion characteristics, which autonomously adapt in response to changes of an incident aerodynamic flow. The metamaterial consists of a slender beam featuring a periodic array or airfo...

  7. A novel approach for design of acoustical enclosure of projectors

    Panahkhahi, Sara

    To create a quiet environment inside buildings, it is necessary to decrease the noise level, which partly originates from electromechanical devices. This study explored a method for designing an acoustic enclosure for projectors that generate noises in a wide band frequency range. The source of noise in projectors is their fans, which cause the structure borne and airborne noise. Fans are required in projectors that use lamps as an illumination source to dissipate the heat emitted from their lamps. Sound measurements were performed to determine the frequency range that is generated by the projector. Based on the data obtained from the measurements, the sound level of the projector and the design of the enclosure were studied. Another aspect of this project was to find a way to cool down the projector while it was operating in a completely sealed enclosure. Based on the information about the power consumption of the projector and the temperature range that the projector can safely operates under, the cooling system was proposed. Finally the sound and temperature measurements were performed on the fabricated prototype of the enclosure to evaluate its functionality.

  8. Development of Energy Efficiency Design Map based on acoustic resonance frequency of suction muffler in compressor

    Highlights: • Development of Energy Efficiency Design Map. • Experimental validation of Energy Efficiency Design Map. • Suggestion regarding the Acoustically Supercharged Energy Efficiency. • Sensitivity analysis of the Energy Efficiency Ratio with respect to acoustic pressure. • Suggestion regarding the hybrid coupling method for acoustic analysis in compressor. - Abstract: The volumetric efficiency of the Internal Combustion (IC) engine and compressor can be increased by properly adjusting the acoustic resonance frequency of the suction muffler or the suction valve timing without any additional equipment or power source. This effect is known as acoustic supercharging. However, the energy efficiency has become more important than the volumetric efficiency because of the energy shortage issue and factors influencing consumers’ purchasing decisions. Therefore, methods for increasing the energy efficiency using the acoustic effect in the suction part of IC engine and compressor should be considered. In this study, a systematic method for improving the energy efficiency using the acoustic effect in the suction part of the compressor used in refrigerators and air conditioners was developed for the first time. This effect is named as the Acoustically Supercharged Energy Efficiency (ASEE). For the ASEE, first, a hybrid coupling method was suggested for the acoustical analysis in the suction part of the compressor. Next, an Energy Efficiency Design Map (EEDM) was proposed. This can serve as a design guide for suction mufflers in terms of the energy efficiency. Finally, sensitivity analyses of the Energy Efficiency Ratio (EER) and total massflow rate with respect to the acoustic pressure were conducted to identify the relationship between the acoustic pressure and the suction valve motion. This provides the physical background for the EEDM

  9. A new highly integrated design and novel lens system for the CSIRO/GEMOC nuclear probe

    The landscape of microanalysis in the geosciences has changed dramatically in the past few years, and with it the role of the Nuclear Microprobe (NMP). The emphasis of NMP applications has shifted to the advanced complementary techniques of quantitative trace-element imaging, in situ non-destructive fluid and solid inclusion analysis, light element microanalysis using PIGE, lattice location using ion micro-channeling, and to applications requiring finer spatial resolution. Recent success of a collaborative ARC bid by the National Key Centre for the Geochemical Evolution and Metallogeny of Continents (GEMOC) and the CSIRO has enabled the development of a new Nuclear Microprobe at the CSIRO designed to meet this challenge and to fully exploit the potential of the NMP in geology. The instrument and some of its features are described. It uses a novel quintuplet magnetic quadrupole lens system, computer controlled beam-shaping, high-resolution microscope optics and a close geometry detector system

  10. Design considerations and sensitivity estimates for an acoustic neutrino detector

    Karg, T; Graf, K; Hoessl, J; Kappes, A; Katz, U; Lahmann, R; Naumann, C; Salomon, K; Karg, Timo; Anton, Gisela; Graf, Kay; Hoessl, Juergen; Kappes, Alexander; Katz, Uli; Lahmann, Robert; Naumann, Christopher; Salomon, Karsten

    2005-01-01

    We present a Monte Carlo study of an underwater neutrino telescope based on the detection of acoustic signals generated by neutrino induced cascades. This provides a promising approach to instrument large detector volumes needed to detect the small flux of cosmic neutrinos at ultra-high energies (E > 1 EeV). Acoustic signals are calculated based on the thermo-acoustic model. The signal is propagated to the sensors taking frequency dependent attenuation into account, and detected using a threshold trigger, where acoustic background is included as an effective detection threshold. A simple reconstruction algorithm allows for the determination of the cascade direction and energy. Various detector setups are compared regarding their effective volumes. Sensitivity estimates for the diffuse neutrino flux are presented.

  11. Combining COMSOL modeling with acoustic pressure maps to design sono-reactors.

    Wei, Zongsu; Weavers, Linda K

    2016-07-01

    Scaled-up and economically viable sonochemical systems are critical for increased use of ultrasound in environmental and chemical processing applications. In this study, computational simulations and acoustic pressure maps were used to design a larger-scale sono-reactor containing a multi-stepped ultrasonic horn. Simulations in COMSOL Multiphysics showed ultrasonic waves emitted from the horn neck and tip, generating multiple regions of high acoustic pressure. The volume of these regions surrounding the horn neck were larger compared with those below the horn tip. The simulated acoustic field was verified by acoustic pressure contour maps generated from hydrophone measurements in a plexiglass box filled with water. These acoustic pressure contour maps revealed an asymmetric and discrete distribution of acoustic pressure due to acoustic cavitation, wave interaction, and water movement by ultrasonic irradiation. The acoustic pressure contour maps were consistent with simulation results in terms of the effective scale of cavitation zones (∼ 10 cm and reactor with a conical bottom was designed to evaluate the treatment capacity (∼ 5 L) for the multi-stepped horn using COMSOL simulations. In this study, verification of simulation results with experiments demonstrates that coupling of COMSOL simulations with hydrophone measurements is a simple, effective and reliable scientific method to evaluate reactor designs of ultrasonic systems. PMID:26964976

  12. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    Ivan Felis; Juan Antonio Martínez-Mora; Miguel Ardid

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. ...

  13. Design and measurement of a flat dielectric lens antenna for beam steering

    Piiroinen, Kalle

    2013-01-01

    In this thesis, flat hemi-elliptic dielectric lens antennas are studied at millimeter wavelengths. The used lens materials are teflon and a commercial plastic called preperm450, developed specifically for high frequency antenna applications. The main focus of this work is in the beam steering properties of the antennas. Proposed antenna structure is suitable for, e.g., automotive radar applications. Two different lens configurations are studied, one based on a dielectric slab waveguide a...

  14. Meta-analysis and review: effectiveness, safety, and central port design of the intraocular collamer lens

    Packer M

    2016-06-01

    Full Text Available Mark Packer Mark Packer MD Consulting, Inc., Boulder, CO, USA Abstract: The purpose of this review is to summarize relevant data from publications appearing in the peer-reviewed scientific literature over the past decade since US Food and Drug Administration approval of the implantable collamer lens (ICL, and, in particular, to review studies relating to sizing methodology, safety, and effectiveness, as well as more recent studies reporting clinical outcomes of the V4c Visian ICL with KS Aquaport, VICMO. A literature search was conducted using two databases, PubMed.gov and Science.gov, to identify all articles published after 2005 related to the Visian ICL (STAAR Surgical, Inc.. Articles were examined for their relevance to sizing methodology, clinical safety, and effectiveness, and the references cited in each article were also searched for additional relevant publications. The literature review revealed that all currently reported methods of determining the best-fit size of the ICL achieve similarly satisfactory results in terms of vault, the safe distance between the crystalline lens and the ICL. Specifically, meta-analysis demonstrated that sulcus-to-sulcus and white-to-white measurement-based sizing methods do not result in clinically meaningful nor statistically significant differences in vault (two-sample two-sided t-test using pooled mean and standard deviations; t (2,594=1.33; P=0.18. The reported rates of complications related to vault are very low, except in two case series where additional risk factors such as higher levels of myopia and older age impacted the incidence of cataract. On the basis of preclinical studies and initial clinical reports, with up to 5 years of follow-up, the new VICMO central port design holds promise for further reduction of complications. Given its safety record and the significant improvement in vision and quality of life that the ICL makes possible, the benefits of ICL implantation outweigh the risks

  15. Meta-analysis and review: effectiveness, safety, and central port design of the intraocular collamer lens.

    Packer, Mark

    2016-01-01

    The purpose of this review is to summarize relevant data from publications appearing in the peer-reviewed scientific literature over the past decade since US Food and Drug Administration approval of the implantable collamer lens (ICL), and, in particular, to review studies relating to sizing methodology, safety, and effectiveness, as well as more recent studies reporting clinical outcomes of the V4c Visian ICL with KS Aquaport, VICMO. A literature search was conducted using two databases, PubMed.gov and Science.gov, to identify all articles published after 2005 related to the Visian ICL (STAAR Surgical, Inc.). Articles were examined for their relevance to sizing methodology, clinical safety, and effectiveness, and the references cited in each article were also searched for additional relevant publications. The literature review revealed that all currently reported methods of determining the best-fit size of the ICL achieve similarly satisfactory results in terms of vault, the safe distance between the crystalline lens and the ICL. Specifically, meta-analysis demonstrated that sulcus-to-sulcus and white-to-white measurement-based sizing methods do not result in clinically meaningful nor statistically significant differences in vault (two-sample two-sided t-test using pooled mean and standard deviations; t (2,594)=1.33; P=0.18). The reported rates of complications related to vault are very low, except in two case series where additional risk factors such as higher levels of myopia and older age impacted the incidence of cataract. On the basis of preclinical studies and initial clinical reports, with up to 5 years of follow-up, the new VICMO central port design holds promise for further reduction of complications. Given its safety record and the significant improvement in vision and quality of life that the ICL makes possible, the benefits of ICL implantation outweigh the risks. PMID:27354760

  16. Design of acoustic logging signal source of imitation based on field programmable gate array

    An acoustic logging signal source of imitation is designed and realized, based on the Field Programmable Gate Array (FPGA), to improve the efficiency of examining and repairing acoustic logging tools during research and field application, and to inspect and verify acoustic receiving circuits and corresponding algorithms. The design of this signal source contains hardware design and software design,and the hardware design uses an FPGA as the control core. Four signals are made first by reading the Random Access Memory (RAM) data which are inside the FPGA, then dealing with the data by digital to analog conversion, amplification, smoothing and so on. Software design uses VHDL, a kind of hardware description language, to program the FPGA. Experiments illustrate that the ratio of signal to noise for the signal source is high, the waveforms are stable, and also its functions of amplitude adjustment, frequency adjustment and delay adjustment are in accord with the characteristics of real acoustic logging waveforms. These adjustments can be used to imitate influences on sonic logging received waveforms caused by many kinds of factors such as spacing and span of acoustic tools, sonic speeds of different layers and fluids, and acoustic attenuations of different cementation planes. (paper)

  17. Transparent gradient index lens for underwater sound based on phase advance

    Martin, Theodore P.; Naify, Christina J.; Skerritt, Elizabeth A.; Layman, Christopher N.; Nicholas, Michael; Calvo, David C.; Orris, Gregory J.; Torrent, Daniel; Sanchez-Dehesa, Jose

    2015-01-01

    Spatial gradients in refractive index have been used extensively in acoustic metamaterial applications to control wave propagation through phase delay. This study reports the design and experimental realization of an acoustic gradient index lens using a sonic crystal lattice that is impedance matched to water over a broad bandwidth. In contrast to previous designs, the underlying lattice features refractive indices that are lower than the water background, which facilitates propagation contro...

  18. Design and fabrication of PMMA-micromachined fluid lens based on electromagnetic actuation on PMMA–PDMS bonded membrane

    The fabrication of a poly(methyl methacrylate) (PMMA)-micromachined fluid lens with an optimally designed built-in electromagnetic actuator was demonstrated in this study. Through a finite element method, the number of winding turns and the distance between magnetic moments were estimated to design an effective and miniaturized electromagnetic actuator. The lens body composed of PMMA structures was simply and rapidly micromachined using computer numerical control micro-milling. The poly(dimethylsiloxane) (PDMS) membranes for electromagnetic actuation were bonded to the PMMA structures by using the proposed PMMA–PDMS bonding technique, which uses an SiO2 intermediate layer. A physical repulsive force produced by the electromagnetic actuator applies a controllable fluidic pressure to a fluidic chamber that is sealed with the PDMS membrane, thus allowing dynamic focusing. The focus tunability of the fabricated lens was 67 diopters with a focus hysteresis of less than 1 mm and a response time of 2 ms. The solenoid of the built-in actuator showed negligible thermal crosstalk to the lens. (paper)

  19. Advanced gradient-index lens design tools to maximize system performance and reduce SWaP

    Campbell, Sawyer D.; Nagar, Jogender; Brocker, Donovan E.; Easum, John A.; Turpin, Jeremiah P.; Werner, Douglas H.

    2016-05-01

    GRadient-INdex (GRIN) lenses have long been of interest due to their potential for providing levels of performance unachievable with traditional homogeneous lenses. While historically limited by a lack of suitable materials, rapid advancements in manufacturing techniques, including 3D printing, have recently kindled a renewed interest in GRIN optics. Further increasing the desire for GRIN devices has been the advent of Transformation Optics (TO), which provides the mathematical framework for representing the behavior of electromagnetic radiation in a given geometry by "transforming" it to an alternative, usually more desirable, geometry through an appropriate mapping of the constituent material parameters. Using TO, aspherical lenses can be transformed to simpler spherical and flat geometries or even rotationally-asymmetric shapes which result in true 3D GRIN profiles. Meanwhile, there is a critical lack of suitable design tools which can effectively evaluate the optical wave propagation through 3D GRIN profiles produced by TO. Current modeling software packages for optical lens systems also lack advanced multi-objective global optimization capability which allows the user to explicitly view the trade-offs between all design objectives such as focus quality, FOV, ▵nand focal drift due to chromatic aberrations. When coupled with advanced design methodologies such as TO, wavefront matching (WFM), and analytical achromatic GRIN theory, these tools provide a powerful framework for maximizing SWaP (Size, Weight and Power) reduction in GRIN-enabled optical systems. We provide an overview of our advanced GRIN design tools and examples which minimize the presence of mono- and polychromatic aberrations in the context of reducing SWaP.

  20. Design of Acoustic Metamaterials based on the Concept of Dual Transmission Line

    Moreau, Anne-Sophie; Lissek, Hervé; Bongard, Frédéric

    2010-01-01

    Within the last years, an increasing number of studies have been carried out in the field of acoustic metamaterials. These artificial composite materials aim at achieving new macroscopic properties, like negative refraction, that are not readily present in nature. In analogy to electromagnetics, where such concepts are more mature, a novel concept of artificial acoustic transmission line has recently been reported, which presents such artificial behavior. In this article, the design of the pr...

  1. Design and Analysis of Underwater Acoustic Networks with Reflected Links

    Emokpae, Lloyd

    Underwater acoustic networks (UWANs) have applications in environmental state monitoring, oceanic profile measurements, leak detection in oil fields, distributed surveillance, and navigation. For these applications, sets of nodes are employed to collaboratively monitor an area of interest and track certain events or phenomena. In addition, it is common to find autonomous underwater vehicles (AUVs) acting as mobile sensor nodes that perform search-and-rescue missions, reconnaissance in combat zones, and coastal patrol. These AUVs are to work cooperatively to achieve a desired goal and thus need to be able to, in an ad-hoc manner, establish and sustain communication links in order to ensure some desired level of quality of service. Therefore, each node is required to adapt to environmental changes and be able to overcome broken communication links caused by external noise affecting the communication channel due to node mobility. In addition, since radio waves are quickly absorbed in the water medium, it is common for most underwater applications to rely on acoustic (or sound) rather than radio channels for mid-to-long range communications. However, acoustic channels pose multiple challenging issues, most notably the high transmission delay due to slow signal propagation and the limited channel bandwidth due to high frequency attenuation. Moreover, the inhomogeneous property of the water medium affects the sound speed profile while the signal surface and bottom reflections leads to multipath effects. In this dissertation, we address these networking challenges by developing protocols that take into consideration the underwater physical layer dynamics. We begin by introducing a novel surface-based reflection scheme (SBR), which takes advantage of the multipath effects of the acoustic channel. SBR works by using reflections from the water surface, and bottom, to establish non-line-of-sight (NLOS) communication links. SBR makes it possible to incorporate both line

  2. Design and fabrication of an elliptical micro-lens array with grating for laser safety

    Li, L. H.; Wu, B. Q.; Chan, C. Y.; Lee, W. B.; Dong, L. H.

    2015-10-01

    With the enormous expansion of laser usage in medicine, industry and research, all facilities must formulate and adhere to specific safety methods that appropriately address user protection. The protective ellipticalal microstructure with grating is a novel technology which can provide the principal means of ensuring against ocular injury, and must be worn at all times during laser operation. On the basis of Fresnel's law and the diffractive law, Solidworks and Lighttools software are applied to design the elliptical micro-lens array and correspondent grating. The height of the microstructure is 100um and its period is 3mm. The period of grating is 5um. It is shown that the amount of emergent light of a specific wavelength (1064nm) can reflect more than 40° from the incident light through simulation, while the incident light is perpendicular to the microstructure. The fabrication adopts the ultra-precision single point diamond method and injection molding method. However, it is found in the test that the surface roughness has a serious effect on the angle between the emergent and incident light. As a result, the element can reflect the vertical incidence beam into a tilted emergent beam with a certain angular degree , as well as protecting users from laser damage injures.

  3. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect. PMID:26585023

  4. Design of a cross-dipole array acoustic logging tool

    Lu Junqiang; Ju Xiaodong; Cheng Xiangyang

    2008-01-01

    When entering an anisotropic formation,a shear wave splits into a fast wave and a slow wave.Based on the principle of four-component cross-dipole acoustic wave measurement,the anisotropy of HTI (Horizontal Transverse Isotropy) formation can be determined.The method of calculating the fast and slow wave data when a shear wave propagates along the borehole axis in anisotropic formation was analyzed,and the implementation of a cross-dipole acoustic logging tool was demonstrated.The tool was composed of transmitter electronics,transmitter mandrel,acoustic isolator,receiver mandrel and main control electronics.Sonde,transmitter circuit,signal receiving and processing circuit,data acquisition system,system control circuit and telemetry interface circuit were presented and analyzed.The test model was used in production wells and standard wells in various areas and the four-component cross-dipole waves were acquired and processed.The waves had good signal-to-noise ratio and clear characteristics,and the fast and slow waveforms,processed slowness curves,anisotropy and fast shear wave azimuth well matched with each other.

  5. The Testing Behind The Test Facility: The Acoustic Design of the NASA Glenn Research Center's World-Class Reverberant Acoustic Test Facility

    Hozman, Aron D.; Hughes, William O.; McNelis, Mark E.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC's Plum Brook Station in Sandusky, Ohio, USA. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA's space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 cu ft in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world's known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada's acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, USA. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

  6. Business model design through a designer's lens: Translating, transferring and transforming cognitive configurations into action

    Simonse, W.L.; Badke-Schaub, P.G.

    2015-01-01

    Strategic managers are challenged to take advantage of digitalisation opportunities related to services of social media and web 2.0 technologies. Business innovations such as crowd sourcing platforms require a new way of integrating business to technology, articulated in a new business model designs

  7. Construction and characteristics of electron-lens systems specifically designed for low energy electron scattering experiments

    Four multi-element tube-lenses are employed in two systems of an electron gun and an analyzer. The former system consists of an electron gun of the Erdman and Zipf type, a three-element tube-lens, a cylindrical mirror analyzer (CMA) and a four-element tube-lens. The latter system consists of a seven-element tube-lens, CMA and a three-element tube-lens. The paraxial equation is solved numerically by the Runge-Kutta method to obtain electron trajectories through each multi-element tube-lens. Focal properties, magnifications, and filling factors are given respectively for every multi-element tube-lens on the basis of the calculated trajectories. Optimum geometries are presented for the systems of low energy electron scattering experiments. The gun system is capable of providing electron beams with energies between a few and 1,000 eV, which have an energy spread below 0.1 eV. The analyzing system has an energy resolution about 0.1 eV. The detection efficiency is to be constant and independent of scattered electron energies in energy loss spectrum measurements. (author)

  8. Classroom acoustics design for speakers’ comfort and speech intelligibility: a European perspective

    Garcia, David Pelegrin; Rasmussen, Birgit; Brunskog, Jonas

    2014-01-01

    experienced at work. With the aim of improving teachers' working conditions, this paper proposes adjustments to current regulatory requirements on classroom acoustics in Europe from novel insights on classroom acoustics design that meet simultaneously criteria of vocal comfort for teachers and speech...... intelligibility for students. Two room acoustic parameters are shown relevant for a speaker: the voice support, linked to vocal effort, and the decay time derived from an oral-binaural impulse response, linked to vocal comfort. Theoretical prediction models for room-averaged values of these parameters are...... combined with a model of speech intelligibility based on the useful-to-detrimental ratio and empirical models of signal-to-noise ratio in classrooms in order to derive classroom acoustic guidelines, taking into account physical volume restrictions linked to the number of students present in a classroom...

  9. Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

    The design of phononic crystals and acoustic metamaterials with tunable and adaptive wave properties remains one of the outstanding challenges for the development of next generation acoustic devices. We report on the numerical and experimental demonstration of a locally resonant acoustic metamaterial with dispersion characteristics, which autonomously adapt in response to changes of an incident aerodynamic flow. The metamaterial consists of a slender beam featuring a periodic array or airfoil-shaped masses supported by a linear and torsional springs. The resonance characteristics of the airfoils lead to strong attenuation at frequencies defined by the properties of the airfoils and the speed on the incident fluid. The proposed concept expands the ability of existing acoustic bandgap materials to autonomously adapt their dispersion properties through fluid-structure interactions, and has the potential to dramatically impact a variety of applications, such as robotics, civil infrastructures, and defense systems

  10. Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

    Casadei, Filippo [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Bertoldi, Katia [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Kavli Institute for Bionano Science, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2014-01-21

    The design of phononic crystals and acoustic metamaterials with tunable and adaptive wave properties remains one of the outstanding challenges for the development of next generation acoustic devices. We report on the numerical and experimental demonstration of a locally resonant acoustic metamaterial with dispersion characteristics, which autonomously adapt in response to changes of an incident aerodynamic flow. The metamaterial consists of a slender beam featuring a periodic array or airfoil-shaped masses supported by a linear and torsional springs. The resonance characteristics of the airfoils lead to strong attenuation at frequencies defined by the properties of the airfoils and the speed on the incident fluid. The proposed concept expands the ability of existing acoustic bandgap materials to autonomously adapt their dispersion properties through fluid-structure interactions, and has the potential to dramatically impact a variety of applications, such as robotics, civil infrastructures, and defense systems.

  11. International Space Station USOS Crew Quarters Ventilation and Acoustic Design Implementation

    Broyan, James Lee, Jr.

    2009-01-01

    The International Space Station (ISS) United States Operational Segment (USOS) has four permanent rack sized ISS Crew Quarters (CQ) providing a private crewmember space. The CQ uses Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air from the ISS Temperature Humidity Control System or the ISS fluid cooling loop connections. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crewmember s head position and reduce acoustic exposure. The CQ interior needs to be below Noise Curve 40 (NC-40). The CQ ventilation ducts are open to the significantly louder Node 2 cabin aisle way which required significantly acoustic mitigation controls. The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

  12. A theoretical design of gradient index multifocal contact lens for correcting presbyopia and an attempt to elicit its performance using ray tracing

    Bakaraju, Ravi C.; Ehrmann, Klaus; Papas, Eric B.; Ho, Arthur

    2009-02-01

    We propose a novel theoretical design of gradient index (GRIN) multifocal contact lens (MFCL) to compensate presbyopia and make predictions regarding its performance on a schematic model eye and to compare its performance with conventional aspheric progressive MFCL.

  13. Design of Deceleration/Acceleration Lens System for Measuring Charge Exchange Cross Sections of Ar+-Ar, Ne+-Ne Collisions and He2+-Ne Collisions

    Design of a deceleration / acceleration lens system has been done by using SIMION computer program. Operating characteristics of the new apparatus have been optimized with the help of SIMION calculations and then experimentally verified. A parallel beam with 2 mm diameter of singly charged argon ions with an energy of 1 keV was started at a distance of 150 mm before the deceleration/acceleration lens system. The first electrode of the deceleration/acceleration lens system was set at zero V. The applied voltage to the gas cell is related to the applied voltages to the lens elements such that a parallel beam at the cell entrance is produced. The relation between the applied voltage to the gas cell and the deceleration energy was studied for different ion trajectories without taking space charge into account. The simulation process was done for the first five electrodes only, considering the symmetry of the deceleration/acceleration lens systems and without space charge

  14. Simulation of autofocus lens design for a cell phone camera with object distance from infinity to 9.754 mm.

    Sun, Wen-Shing; Tien, Chuen-Lin; Pan, Jui-Wen; Huang, Kai-Chang; Chu, Pu-Yi

    2015-10-01

    This paper presents the simulation of an autofocus lens design with large depth of field for a cell phone camera. The object distance of the lens is from infinity to 9.754 mm. When the object distance is from infinity to 550 mm, the value of the modulation transfer function (MTF) is greater than 0.6 for the spatial frequency of 114 lp/mm, the optical distortion is less than 1.5%, and the relative illumination is greater than 67%. When the object distance is from 325 to 9.754 mm, the MTF values is greater than 0.4 for close-up shooting. The optical distortion is less than 1.454%, and the relative illumination is greater than 68.8%. PMID:26479654

  15. An acoustic metasurface design for wave motion conversion of longitudinal waves to transverse waves using topology optimization

    Noguchi, Y.; Yamada, T.; Otomori, M.; Izui, K.; Nishiwaki, S.

    2015-11-01

    This letter presents an acoustic metasurface that converts longitudinal acoustic waves into transverse elastic waves in an acoustic-elastic coupled system. Metasurface configurations are obtained by a level set-based topology optimization method, and we describe the mechanism that changes the direction of the wave motion. Numerical examples of 2D problems with prescribed frequencies of incident acoustic waves are provided, and transverse elastic wave amplitudes are maximized by manipulating the propagation of the acoustic waves. Frequency analysis reveals that each of the different metasurface designs obtained for different wavelengths of incident waves provides peak response at the target frequency.

  16. The acoustical design of vehicles-a challenge for qualitative evaluation

    Schulte-Fortkamp, Brigitte; Genuit, Klaus; Fiebig, Andre

    2005-09-01

    Whenever the acoustical design of vehicles is explored, the crucial question about the appropriate method of evaluation arises. Research shows that not only acoustic but also non-acoustic parameters have a major influence on the way sounds are evaluated. Therefore, new methods of evaluation have to be implemented. Methods are needed which give the opportunity to test the quality of the given ambience and to register the effects and evaluations in their functional interdependence as well as the influence of personal and contextual factors. Moreover, new methods have to give insight into processes of evaluation and their contextual parameters. In other words, the task of evaluating acoustical ambiences consists of designating a set of social, psychological, and cultural conditions which are important to determine particular individual and collective behavior, attitudes, and also emotions relative to the given ambience. However, no specific recommendations exist yet which comprise particular descriptions of how to assess those specific sound effects. That is why there is a need to develop alternative methods of evaluation with whose help effects of acoustical ambiences can be better predicted. A method of evaluation will be presented which incorporates a new sensitive approach for the evaluation of vehicle sounds.

  17. Interior Acoustic Analysis for Early Use in Design Project

    National Aeronautics and Space Administration — The design of an aircraft is a highly iterative process. During the conceptual design phase there is no time for developing detailed simulation models and decisions...

  18. Design and development of a synthetic acoustic antenna for highly directional sound measurements

    Boone, M.M.

    1987-01-01

    Design and development of an acoustic microphone array for sound measurements outdoors, with applications in industrial noise and traffic noise. The microphone array has a flexible length of 10 to 76 m and covers the octave band from 125 to 1000 Hz (later extended to 2000 Hz). The angular resolution is 1.5 degrees.

  19. Design of prototype two element optically stimulated luminescence dosimeter badge for eye lens monitoring

    A prototype two element eye lens dosimeter badge based on highly sensitive α-Al2O3: C optically stimulated luminescence dosimeters (OSLDs) was designed and developed. The badge consists of a plastic card in which two thin α-Al2O3: C optically stimulated luminescence (OSL) discs are placed. The OSLDs in the plastic card (when inserted into plastic cassette) are covered with energy compensation filters made up of 0.3 mm thick Cu and 1.35 mm thick Teflon discs positioned symmetrically on both sides of the dosimeter. The OSLD badge is useful for monitoring doses from photons and beta particles. In this paper, theoretical studies using Monte Carlo method as well as using the analytical technique have been performed to study the energy response of the bare α-Al2O3: C based disc dosimeters. These dosimeter discs have been found to exhibit over-response by a factor of ∼ 3.4 at ∼ 33 keV photon energy, whereas, beyond 80 keV photon energy, the response is nearly energy independent. Studies have also been performed to find the energy response of the α-Al2O3: C disc dosimeters under different metal filters, viz., Al, Cu, Sn etc., and under various thicknesses of Teflon. From theoretical simulations, it has been found that 0.3 mm thick Cu is sufficient to correct the over-response in lower energy region within acceptable limits. Further, Teflon disc (DuPont, USA) having thickness of 1.35 mm is found to be the optimized choice as filter for the second dosimeter disc. It is worth mentioning that the ratio of the response of the OSL disc under Teflon to that under Cu filter indicates average energy of X-ray photons and same is used to correct the over-response as well as to estimate the quantity Hp(3). Also for higher photon energy region, the readout of the dosimeter disc under Teflon filter directly measures the quantity Hp(3). Same holds true for beta particles having maximum beta energy, Emax beyond 0.7 MeV. (author)

  20. Design of no blind area perimeter intrusion recognition system based on fisheye lens

    Dai, Jun-jian; Han, Wen-bo

    2013-08-01

    The Perimeter intrusion recognition technology has slowly become an indispensable function in the intelligent video surveillance system. The existed always use the multiple video acquisition nodes to respectively control a monitoring area and each node alarm independently. However, the existed solutions are difficult to avoid the existence of monitoring blind area, and can't suitable for the perimeter environment with irregular outline, and at the same time, because of the too many nodes, it inevitably decreased the overall accuracy of intrusion recognition system and increased the cost of system. To avoid the above defects, this paper mainly talks about the following three aspects. Firstly, we used the fisheye lens as the optical system of video acquisition node, and it evidently enhances each node's information acquisition ability. And in this way, we just need to decorate a small amount of video acquisition node to get no blind area environmental information of the perimeter when against a larger monitoring situation. Secondly, due to the inexistence of blind area, the system will have enough video image information to generate the 360 degree panoramic image for monitoring environment, and finally the system server collected the wide-angle image information to splice into the panoramic video image. Finally, the system will use the panoramic image to complete the intrusion behavior recognition, thus we can effectively avoid the parallel computation in many nodes independently invasion of recognition, and this can greatly reduces the dependence for the multiple CPU operation platform and enhances the reliability of the system. The field test results show that, with the help of this paper's solution, the perimeter of the invasion of recognition system can effectively avoids the recognition of blind area. In the same recognition algorithm and same level delay premise, it greatly reduces the monitoring system server configuration requirements, especially for the

  1. Structural-Acoustic Simulations in Early Airframe Design Project

    National Aeronautics and Space Administration — The structural design during the early development of an aircraft focuses on strength, fatigue, corrosion, maintenance, inspection, and manufacturing. Usually the...

  2. Classroom acoustics design for speakers’ comfort and speech intelligibility: a European perspective

    Garcia, David Pelegrin; Rasmussen, Birgit; Brunskog, Jonas

    2014-01-01

    Current European regulatory requirements or guidelines for reverberation time in classrooms have the goal of enhancing speech intelligibility for students and reducing noise levels in classrooms. At the same time, school teachers suffer frequently from voice problems due to high vocal load...... experienced at work. With the aim of improving teachers' working conditions, this paper proposes adjustments to current regulatory requirements on classroom acoustics in Europe from novel insights on classroom acoustics design that meet simultaneously criteria of vocal comfort for teachers and speech...... intelligibility for students. Two room acoustic parameters are shown relevant for a speaker: the voice support, linked to vocal effort, and the decay time derived from an oral-binaural impulse response, linked to vocal comfort. Theoretical prediction models for room-averaged values of these parameters are...

  3. Analytical models for use in fan inflow control structure design. Inflow distortion and acoustic transmission models

    Gedge, M. R.

    1979-01-01

    Analytical models were developed to study the effect of flow contraction and screening on inflow distortions to identify qualitative design criteria. Results of the study are that: (1) static testing distortions are due to atmospheric turbulence, nacelle boundary layer, exhaust flow reingestion, flow over stand, ground plane, and engine casing; (2) flow contraction suppresses, initially, turbulent axial velocity distortions and magnifies turbulent transverse velocity distortions; (3) perforated plate and gauze screens suppress axial components of velocity distortions to a degree determined by the screen pressure loss coefficient; (4) honeycomb screen suppress transverse components of velocity distortions to a degree determined by the length to diameter ratio of the honeycomb; (5) acoustic transmission loss of perforated plate is controlled by the reactance of its acoustic impedance; (6) acoustic transmission loss of honeycomb screens is negligible; and (7) a model for the direction change due to a corner between honeycomb panels compares favorably with measured data.

  4. Design of object surveillance system based on enhanced fish-eye lens

    Jianhui Wu; Kuntao Yang; Qiaolian Xiang; Nanyang Zhang

    2009-01-01

    A new method is proposed for the object surveillance system based on the enhanced fish-eye lens and the high speed digital signal processor (DSP). The improved fish-eye lens images an ellipse picture on the charge-coupled device (CCD) surface, which increases both the utilization rate of the 4:3 rectangular CCD and the imaging resolution, and remains the view angle of 183°. The algorithm of auto-adapted renewal background subtraction (ARBS) is also explored to extract the object from the monitoring image. The experimental result shows that the ARBS algorithm has high anti-jamming ability and high resolution, leading to excellent object detecting ability from the enhanced elliptical fish-eye image under varies en-vironments. This system has potential applications in different security monitoring fields due to its wide monitoring space, simple structure, working stability, and reliability.

  5. Antenna and coil design for wireless signal detection and charging of embedded power active contact lens.

    Ng, Benny; Heckler, Paul; Do, Alex; Azar, Phillip; Leon, Errol; Smilkstein, Tina

    2014-01-01

    This paper presents a screen printed 2.4 GHz antenna and induction charging coil for an active contact lens with a single large pixel user display and on-board 3.8 V 5 uAh rechargeable battery. The antenna traces are printed using silver conductive paste on a 25 um polyethylene terephthalate (PET) substrate. The incoming signal from the antenna feeds into an IC that amplifies and rectifies the signal. The coil provides wireless energy transfer to inductively charge a thin film battery [1] located on the contact lens. The printed antenna achieved a S11 of -4 dB at 2.4 GHz and a gain of -13 dB. PMID:25571353

  6. A Review of Cavity Design for Kerr Lens Mode-Locked Solid-State Lasers

    Shai Yefet

    2013-12-01

    Full Text Available We provide a critical review of the fundamental concepts of Kerr lens mode-locking (KLM, along with a detailed description of the experimental considerations involved in the realization of a mode-locked oscillator. In addition, we review recent developments that overcome inherent limitations and disadvantages in standard KLM lasers. Our review is aimed mainly at readers who wish to realize/maintain such an oscillator or for those who wish to better understand this major experimental tool.

  7. Focusing Ultrasound with Acoustic Metamaterial Network

    Zhang, Shu; Fang, Nicholas

    2009-01-01

    We present the first experimental demonstration of focusing ultrasound waves through a flat acoustic metamaterial lens composed of a planar network of subwavelength Helmholtz resonators. We observed a tight focus of half-wavelength in width at 60.5 KHz by imaging a point source. This result is in excellent agreement with the numerical simulation by transmission line model in which we derived the effective mass density and compressibility. This metamaterial lens also displays variable focal length at different frequencies. Our experiment shows the promise of designing compact and light-weight ultrasound imaging elements.

  8. Unique rod lens/video system designed to observe flow conditions in emergency core coolant loops of pressurized water reactors

    Techniques and equipment are described which are used for video recordings of the single- and two-phase fluid flow tests conducted with the PKL Spool Piece Measurement System designed by Lawrence Livermore Laboratory and EG and G Inc. The instrumented spool piece provides valuable information on what would happen in pressurized water reactor emergency coolant loops should an accident or rupture result in loss of fluid. The complete closed-circuit television video system, including rod lens, light supply, and associated spool mounting fixtures, is discussed in detail. Photographic examples of test flows taken during actual spool piece system operation are shown

  9. Acoustical standards and criteria documentation of sustainability in hospital design and construction

    Evans, Jack,; Himmel, Chad

    2012-01-01

    The Leadership in Energy and Environmental Design (LEED) rating system, developed by the United States Green Building Council (USGBC) has multiple categories, including a 2009 version for healthcare buildings. Determination and award of Interior Environmental Quality (IEQ) rating points for Acoustics requires theoretical calculation in design phase of ambient sound, privacy and intrusive outdoor noise relative to allowable criteria or performance validation testing after construction. This ca...

  10. Acoustic intensity methods and their applications to vector sensor use and design

    Naluai, Nathan Kahikina

    Applications of acoustic intensity processing methods to vector sensor output signals are investigated for three specific cases: acoustic intensity scattering, spatial correlations of intensities, and conceptual design of a high frequency inertial vector sensor with a novel suspension. An overview of intensity processing is presented and the concept of a complex intensity is illustrated. Measurement techniques for determining the complex intensity spectra from the signals received by a standard acoustic vector sensor are demonstrated. Acoustic intensity processing of signals from SSQ-53D sonobuoys is used to enhance the detection of submerged bodies in bi-static sonar applications. Deep water experiments conducted at Lake Pend Oreille in northern Idaho are described. A submerged body is located between a source and a number of SSQ-53D sonobuoy receivers. Scalar pressure measurements change by less than 0.5 dB when the scattering body is inserted in the field. The phase of the orthogonal intensity component shows repeatable and strong variations of nearly 55°. The classical solution for the spatial correlation of the pressure field is presented. The derivation techniques are expanded to derive previously unsolved analytic forms for the spatial correlations of separated intensity field components based on combinations of the solutions for various pressure and velocity components. Experimental validation of these correlation solutions are performed computationally and in an underwater environment. The computational experiments are designed to test highly controlled variations to the idealized case (e.g. sound field content, transducer phasing issues, additive output noise, etc.) Additional verification is provided from physical tests measuring the correlations between a pair of acoustic vector sensors in a large reverberant tank which is excited acoustically with broadband noise. The results successfully corroborate the derivation methods for correlations of

  11. Directional excitation of the designer surface acoustic waves

    Lu, Jiuyang; Qiu, Chunyin; Ke, Manzhu; Liu, Zhengyou

    2015-05-01

    We propose an efficient design route to realize directional excitation of the structure-induced surface waves for airborne sound. The whole system consists of a periodically corrugated rigid plate combining with a pair of asymmetric narrow slits. The directional excitation of the mimicked surface waves stems from the destructive interference between the evanescent waves emitted from the double slits. The directionality can be switched conveniently by tuning the external frequency. The theoretical prediction is validated well by simulations and experiments. Promising applications can be anticipated such as in designing compact devices for airborne sound.

  12. Acoustic Treatment Design Scaling Methods. Volume 1; Overview, Results, and Recommendations

    Kraft, R. E.; Yu, J.

    1999-01-01

    Scale model fan rigs that simulate new generation ultra-high-bypass engines at about 1/5-scale are achieving increased importance as development vehicles for the design of low-noise aircraft engines. Testing at small scale allows the tests to be performed in existing anechoic wind tunnels, which provides an accurate simulation of the important effects of aircraft forward motion on the noise generation. The ability to design, build, and test miniaturized acoustic treatment panels on scale model fan rigs representative of the fullscale engine provides not only a cost-savings, but an opportunity to optimize the treatment by allowing tests of different designs. The primary objective of this study was to develop methods that will allow scale model fan rigs to be successfully used as acoustic treatment design tools. The study focuses on finding methods to extend the upper limit of the frequency range of impedance prediction models and acoustic impedance measurement methods for subscale treatment liner designs, and confirm the predictions by correlation with measured data. This phase of the program had as a goal doubling the upper limit of impedance measurement from 6 kHz to 12 kHz. The program utilizes combined analytical and experimental methods to achieve the objectives.

  13. Design and fabrication of a mid-wavelength infrared Fresnel lens via liquid poly(methyl methacrylate)

    Most popular materials for lenses, such as glass, have high absorption in the infrared range. Due to material restriction, infrared lenses are usually much more expensive. In this paper, we discussed a ubiquitous polymer material, poly(methyl methacrylate) (PMMA), for mid-wavelength infrared (MWIR) applications. PMMA is a low cost material and is widely used in daily life. We examined its optical properties in the mid-infrared range and found that poly(methyl methacrylate) is a highly promising material for MWIR lenses. Besides, liquid PMMA can be formed and solidified easily. Utilizing these characteristics, we proposed a novel way to fabricate PMMA lenses for MWIR range (wavelength from 3.6 to 5 µm). The fabrication process is much easier and less expensive compared with traditional machining processes. We have designed a PMMA Fresnel lens, which has f-number of 1.40, diameter of 10 mm and focal length of 14 mm. We also successfully fabricated the PMMA Fresnel lens using the molding process. Both structure and optical analyses show that the PMMA Fresnel lenses could meet the design parameters. (paper)

  14. Design of a solar collector system formed by a Fresnel lens and a CEC coupled to plastic fibers

    Viera-González, Perla M.; Sánchez-Guerrero, Guillermo E.; Ceballos-Herrera, Daniel E.; Selvas-Aguilar, Romeo

    2015-08-01

    Among the main challenges for systems based in solar concentrators and plastic optical fibers (POF) the accuracy needed for the solar tracking is founded. One approach to overcome these requirements is increasing acceptance angle of the components, usually by secondary optical elements (SOE), however this technique is effective for photovoltaic applications but it has not been analyzed for systems coupled to POFs for indoor illumination. On this subject, it is presented a numerical analysis of a solar collector assembled by a Fresnel lens as primary optical element (POE) combined with a compound elliptical concentrator (CEC) coupled to POF in order to compare its performance under incidence angle direction and also to show a trade-off analysis for two different Fresnel lens shapes, imaging and nonimaging, used in the collector system. The description of the Fresnel lenses and its designs are included, in addition to the focal areas with space and angular distribution profiles considering the optimal alignment with the source and maximum permissible incident angle for each case. For both systems the coupling between the optical components is analyzed and the total performance is calculated, having as result its comparison for indoor illumination. In both cases, the systems have better performance increasing the final output power, but the angular tolerance only was improved for the system with nonimaging concentrator that had an efficiency over 80% with acceptance angles 𝜃𝑖 ≤ 2° and, the system integrated by the imaging lens, presented an efficiency ratio over 75% for acceptance angles 𝜃𝑖 ≤ 0.7°.

  15. Design of a clip product based on customer needs for playing acoustic music

    Veytizou, Julien; Xuereb, Hugo; THOMANN, Guillaume

    2013-01-01

    International audience Inclusion of uses and users in product design remains a challenge to take up; especially when their characterizations are very specific (it's the case with disabled persons). In the musical domain, a lot of adapted interfaces are manufactured to enable users with disabilities to play music from digital audio. But few of them allow the music practice on acoustic instruments, which is one of the goal identified by the AE2M non-profit association (Ergonomic Adapta-tion ...

  16. Chamber Hall Threshold Design and Acoustic Surface Shaping with Parametric Modeling

    Garber, Emily Ann

    2011-01-01

    The architectural opportunity to develop the sound and light lock of a performance venue as a space that engages and prepares the audience for a performance is one that is sadly missing from most halls. I have explored the development of this threshold as a true architectural space, one that enhances the overall experience for the audience members. And by introducing a parametric process into the architectural and acoustic development, have proposed a unique process for the design of concert ...

  17. Focusing of Acoustic Waves through Acoustic Materials with Subwavelength Structures

    Xiao, Bingmu

    2013-05-01

    In this thesis, wave propagation through acoustic materials with subwavelength slits structures is studied. Guided by the findings, acoustic wave focusing is achieved with a specific material design. By using a parameter retrieving method, an effective medium theory for a slab with periodic subwavelength cut-through slits is successfully derived. The theory is based on eigenfunction solutions to the acoustic wave equation. Numerical simulations are implemented by the finite-difference time-domain (FDTD) method for the two-dimensional acoustic wave equation. The theory provides the effective impedance and refractive index functions for the equivalent medium, which can reproduce the transmission and reflection spectral responses of the original structure. I analytically and numerically investigate both the validity and limitations of the theory, and the influences of material and geometry on the effective spectral responses are studied. Results show that large contrasts in impedance and density are conditions that validate the effective medium theory, and this approximation displays a better accuracy for a thick slab with narrow slits in it. Based on the effective medium theory developed, a design of a at slab with a snake shaped" subwavelength structure is proposed as a means of achieving acoustic focusing. The property of focusing is demonstrated by FDTD simulations. Good agreement is observed between the proposed structure and the equivalent lens pre- dicted by the theory, which leads to robust broadband focusing by a thin at slab.

  18. Rock and pop venues acoustic and architectural design

    Adelman-Larsen, Niels Werner

    2014-01-01

    Popular music plays an substantial role in most people’s life. The demand and financial revenue of Rock and pop concerts is large and still increasing. Though 80% of the music turnover is done in Rock and Pop Music, books assess only Classical concert and opera houses. However, the requirements for pop music halls are different from classical Music and opera houses. This book closes this gap including the following features: In part one, the book A. Gives a objective methodology to assess Rock and Pop Music Venues B. Shows essential construction details and choices of building materials in the design of new venues or the renovation of old ones. In part two, the book C. Presents a set of famous European rock and pop venues, their architecture, their beauty and their properties. D. These Venues are assessed by a new and comparably simple method to objectively rate halls. Subjective data complete the assessment and give a full picture of the sound quality of a venue.

  19. Acoustic cloaking and transformation acoustics

    Chen Huanyang [School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006 (China); Chan, C T, E-mail: kenyon@ust.h, E-mail: phchan@ust.h [Department of Physics and the William Mong Institute of NanoScience and Technology, The Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong)

    2010-03-24

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  20. Acoustic cloaking and transformation acoustics

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  1. Development of design of CLA: target lens line-focusing system

    Li, Xuechun; Zhu, Jianqiang

    1999-08-01

    In this paper the principle of CLA-target system to obtain focal line with homogenous intensity distribution was described. And tow new structure modal CLA used for improving the homogeneous of focal line was described and the numerical results of the classical CLA and new type CLA was also given. Those result showed that the focal line long-range intensity distribution can be improved greatly by using CLA with optimized unequal cylindrical lens element for beam with Gaussian intensity distribution and by using hybrid element CLA for the case of super-Gaussian distribution. The optimal process was treated by simulated annealing method. The intensity modulation decreased to 0.7 percent for optimized 4-element unequal width CLA system when incident laser with Gaussian section distribution.

  2. DESIGN OF INTELLIGENT CONTROL SYSTEM USING ACOUSTIC PARAMETERS FOR GRINDING MILL OPERATION

    Sonali Sen

    2013-02-01

    Full Text Available This paper utilizes acoustic parameters such as FS,NC, N, P, INC, FL, FH, W for acoustic signals S of different running conditions of a ballmill to deriveout the acoustic signatures and hence control signals, which is to be used for designing the control systems of the mill. The parameters FS, NC, N, P, INC, FL, FH and W are represented by sample rate in Hz, number of cepstral coefficients, length of frame in samples, number of filters in filter bank, frame increment, low end of the lowest filter, high end of highest filter and the window over which the analysis is to be performed respectively. The work establishes an appropriate theoretical background that helps to predict dynamic breakage characteristics with respect to particle size distribution of materials, adequately supported by experimental data. The signatures of different running conditions of grinding mill have been extracted from the captured signal in time frame these have been used as feedback signal to monitor the grinding operation. Condenser based microphones have been used for capturing acoustic signals in time domain directly in computers and stored for further analysis. Matlab R2010b has been used for different analysis of the experiment. On analyzing the signatures, it has been observed whether the fines are produced progressively to attain the desired size range or the mill producing undesired products. Thus, the approach has been used in this paper has the ability to arrive in the stage of optimum grinding by tuning parameters of the mill in real time, and also it can prevent the mill to enter into an erroneous state. Moreover, on study it has found that the present scheme can be used more accurately in comparison to the earlier work of the author. This paper presents an implementation scheme to use acoustic signal as the control signal to regulate the operation of a grinding mill.

  3. Structure design on SH wave electromagnetic acoustic transducer (EMAT)

    is weak in the magnet structure of SH wave EMAT. This is considered to be due to the interaction between the magnetic fields of the adjoining magnets. In the case of the arrangement half-period being 2.5 mm, a dimension of 5 mm in height is found large enough to yield nearly the strongest magnetic flux density distribution. Nevertheless, it is better to use the magnet structure with 7 mm height dimension if the dispersion variation of magnetic property during the production process is taken into account. This result is of significance. It implies that, to reduce the weight of EMAT, one is only need to decrease the height dimension of magnet to an appropriate size. 4. The larger arrangement half-period gives rise to a better liftoff performance. However, it is usually difficult to balance between an appropriate arrangement half-period and a good liftoff performance. Because a magnet structure with large arrangement half-period should have a good liftoff performance but it has to work in lower frequency range, results in a worse detection resolution. It should be emphasized that the work to design the magnet structure of SH wave EMAT for use at elevated temperature has to be undertaken and the optimization of the parameters of EMAT is necessary. This will be addressed in detail later. (author)

  4. 盛京大剧院的声学设计%Acoustic Design of Shengjing Grand Theatre

    杨志刚

    2015-01-01

    Some related key points about Shengjing grand theatre are introduced, including the functional and architectural overview, major acoustical design technical indicators, acoustic design requirements of decoration materials in surface of the audience hall, and acoustic test results of each state of use after completion of the theatre.%介绍了盛京大剧院的功能及建筑概况、主要建声设计技术指标、观众厅表面装修用材的声学设计要求,以及建成后各种使用状态的建声测试结果。

  5. The design of an acoustic data link for a deep-sea probe

    The report describes a digital computer simulation of the performance of possible acoustic digital data link designs for use with a deep ocean penetrometer. It concludes with a description of the acoustic and electronic parts of a prototype system. The digital computer was developed with the assumption that the transmitter would need to be able to pass a low error rate data signal vertically upwards through some tens of metres of sea-bed sediment as well as some thousands of metres of sea water. The model allowed for variability in sediment attenuation, sea-state, transmitter power and modulation technique. It was concluded that, at acceptable transmitter powers, a useable signal should be recoverable under all expected environmental conditions. The prototype system was built and tested in laboratory conditions. The tests indicated that satisfactory performance should be achievable with a field equipment derived from this prototype. (author)

  6. Contrast visual acuity after multifocal intraocular lens implantation:aspheric versus spherical design

    Jun-Hua Li

    2014-02-01

    Full Text Available AIM: To evaluate contrast visual acuity (CVA after implantation of an aspheric apodized diffractive intraocular lens (IOL or a spherical apodized diffractive IOL in cataract surgery.METHOD: This prospective randomized controlled study with a 12-month follow-up compared the results of cataract surgery with implantation of an aspheric AcrySof ReSTOR SN6AD3 IOL (30 eyes and a spherical AcrySof ReSTOR SN60D3 IOL (30 eyes. CVA with best distance correction was measured at 4 contrast levels (100%, 25%, 10% and 5% under 3 levels of chart luminance [250, 85 and 25 candelas per square meter (cd/m2] using a multi-functional visual acuity tester (MFVA-100.RESULTS:At 12 months after surgery, there were no statistically significant differences in 100% CVA and 25% CVA under 250cd/m2 (P100%=0.875 and P25%=0.057 and 85cd/m2 (P100%=0.198 and P25%=0.193 between the aspheric group and the spherical group. However, the 10% CVA and 5% CVA were significant better in aspheric group than spherical group under 250cd/m2 (P10%=0.042 and P5%=0.007 and 85cd/m2 (P10%=0.002 and P5%=0.039. Under the luminance level of 25cd/m2, no significant differences was found in the 100% CVA between the 2 group (P100%=0.245, while aspheric group had better visual acuity in the remaining 3 contracts (P25%=0.023, P10%=0.026 and P5%=0.002, respectively.CONCULSION:The aspheric AcrySof ReSTOR SN6AD3 IOL provided patients with better low-contrast visual acuity than the spherical AcrySof ReSTOR SN60D3 IOL.Keyword:cataract surgery; intraocular lens; contrast sensitivity; visual acuity

  7. The acoustic performance of double-skin facades: A design support tool for architects

    Batungbakal, Aireen

    This study assesses and validates the influence of measuring sound in the urban environment and the influence of glass facade components in reducing sound transmission to the indoor environment. Among the most reported issues affecting workspaces, increased awareness to minimize noise led building designers to reconsider the design of building envelopes and its site environment. Outdoor sound conditions, such as traffic noise, challenge designers to accurately estimate the capability of glass facades in acquiring an appropriate indoor sound quality. Indicating the density of the urban environment, field-tests acquired existing sound levels in areas of high commercial development, employment, and traffic activity, establishing a baseline for sound levels common in urban work areas. Composed from the direct sound transmission loss of glass facades simulated through INSUL, a sound insulation software, data is utilized as an informative tool correlating the response of glass facade components towards existing outdoor sound levels of a project site in order to achieve desired indoor sound levels. This study progresses to link the disconnection in validating the acoustic performance of glass facades early in a project's design, from conditioned settings such as field-testing and simulations to project completion. Results obtained from the study's facade simulations and facade comparison supports that acoustic comfort is not limited to a singular solution, but multiple design options responsive to its environment.

  8. Manipulation of transmitted wave front using ultrathin planar acoustic metasurfaces

    Zhai, Shilong; Chen, Huaijun; Ding, Changlin; Shen, Fangliang; Luo, Chunrong; Zhao, Xiaopeng

    2015-09-01

    Nowadays, the acoustic devices are developing toward miniaturization. However, conventional materials can hardly satisfy the requirements because of their large size and complex manufacturing process. The introduction of acoustic metasurfaces has broken these restrictions, as they are able to manipulate sound waves at will by utilizing ultrathin planar metamaterials. Here, a simple acoustic metasurface is designed and characterized, whose microstructure is constructed with a cavity filled with air and two elastic membranes on the ends of cavity. By appropriately optimizing the configurations of microstructures, the steering of transmitted wave trajectory is demonstrated, and some extraordinary phenomena are realized at 3.5 kHz, such as planar acoustic axicon, acoustic lens, the conversion from spherical waves to plane waves, and the transformation from propagating waves to surface waves.

  9. James Webb Space Telescope Optical Simulation Testbed II. Design of a Three-Lens Anastigmat Telescope Simulator

    Choquet, Élodie; N'Diaye, Mamadou; Perrin, Marshall D; Soummer, Rémi

    2014-01-01

    The James Webb Space Telescope (JWST) Optical Simulation Testbed (JOST) is a tabletop experiment designed to reproduce the main aspects of wavefront sensing and control (WFSC) for JWST. To replicate the key optical physics of JWST's three-mirror anastigmat (TMA) design at optical wavelengths we have developed a three-lens anastigmat optical system. This design uses custom lenses (plano-convex, plano-concave, and bi-convex) with fourth-order aspheric terms on powered surfaces to deliver the equivalent image quality and sampling of JWST NIRCam at the WFSC wavelength (633~nm, versus JWST's 2.12~micron). For active control, in addition to the segmented primary mirror simulator, JOST reproduces the secondary mirror alignment modes with five degrees of freedom. We present the testbed requirements and its optical and optomechanical design. We study the linearity of the main aberration modes (focus, astigmatism, coma) both as a function of field point and level of misalignments of the secondary mirror. We find that t...

  10. Design and Instrumentation of a Measurement and Calibration System for an Acoustic Telemetry System

    Zhiqun Deng

    2010-03-01

    Full Text Available The Juvenile Salmon Acoustic Telemetry System (JSATS is an active sensing technology developed by the U.S. Army Corps of Engineers, Portland District, for detecting and tracking small fish. It is used primarily for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more “fish-friendly” hydroelectric facilities. The objective of this study was to design and build a Measurement and Calibration System (MCS for evaluating the JSATS components, because the JSATS requires comprehensive acceptance and performance testing in a controlled environment before it is deployed in the field. The MCS consists of a reference transducer, a water test tank lined with anechoic material, a motion control unit, a reference receiver, a signal conditioner and amplifier unit, a data acquisition board, MATLAB control and analysis interface, and a computer. The fully integrated MCS has been evaluated successfully at various simulated distances and using different encoded signals at frequencies within the bandwidth of the JSATS transmitter. The MCS provides accurate acoustic mapping capability in a controlled environment and automates the process that allows real-time measurements and evaluation of the piezoelectric transducers, sensors, or the acoustic fields. The MCS has been in use since 2009 for acceptance and performance testing of, and further improvements to, the JSATS.

  11. Design and instrumentation of a measurement and calibration system for an acoustic telemetry system.

    Deng, Zhiqun; Weiland, Mark; Carlson, Thomas; Eppard, M Brad

    2010-01-01

    The Juvenile Salmon Acoustic Telemetry System (JSATS) is an active sensing technology developed by the U.S. Army Corps of Engineers, Portland District, for detecting and tracking small fish. It is used primarily for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more "fish-friendly" hydroelectric facilities. The objective of this study was to design and build a Measurement and Calibration System (MCS) for evaluating the JSATS components, because the JSATS requires comprehensive acceptance and performance testing in a controlled environment before it is deployed in the field. The MCS consists of a reference transducer, a water test tank lined with anechoic material, a motion control unit, a reference receiver, a signal conditioner and amplifier unit, a data acquisition board, MATLAB control and analysis interface, and a computer. The fully integrated MCS has been evaluated successfully at various simulated distances and using different encoded signals at frequencies within the bandwidth of the JSATS transmitter. The MCS provides accurate acoustic mapping capability in a controlled environment and automates the process that allows real-time measurements and evaluation of the piezoelectric transducers, sensors, or the acoustic fields. The MCS has been in use since 2009 for acceptance and performance testing of, and further improvements to, the JSATS. PMID:22319288

  12. Acoustic and electo-acoustic design of the Country Music Hall of Fame and Museum in Nashville

    Haas, Steve

    2003-04-01

    The Country Music Hall of Fame and Museum in Nashville is the newest major music museum to open in the United States. It represents the latest in acoustic and audio delivery technology to provide excellent sound quality and sound control for museum public, performance and exhibit spaces. The author will present some of the unique approaches and technologies that were first implemented into this facility and explain how the acoustic/electroacoustic interface allowed the Hall of Fame to maximize their use of sound in the exhibits as well as hold simultaneous special functions in many of the public spaces.

  13. Structural design of contact lens-based drug delivery systems; in vitro and in vivo studies of ocular triggering mechanisms.

    Mahomed, Anisa; Wolffsohn, James S; Tighe, Brian J

    2016-04-01

    This study identifies and investigates the potential use of in-eye trigger mechanisms to supplement the widely available information on release of ophthalmic drugs from contact lenses under passive release conditions. Ophthalmic dyes and surrogates have been successfully employed to investigate how these factors can be drawn together to make a successful system. The storage of a drug-containing lens in a pH lower than that of the ocular environment can be used to establish an equilibrium that favours retention of the drug in the lens prior to ocular insertion. Although release under passive conditions does not result in complete dye elution, the use of mechanical agitation techniques which mimic the eyelid blink action in conjunction with ocular tear chemistry promotes further release. In this way differentiation between passive and triggered in vitro release characteristics can be established. Investigation of the role of individual tear proteins revealed significant differences in their ability to alter the equilibrium between matrix-held and eluate-held dye or drug. These individual experiments were then investigated in vivo using ophthalmic dyes. Complete elution was found to be achievable in-eye; this demonstrated the importance of that fraction of the drug retained under passive conditions and the triggering effect of in-eye conditions on the release process. Understanding both the structure-property relationship between drug and material and in-eye trigger mechanisms, using ophthalmic dyes as a surrogate, provides the basis of knowledge necessary to design ocular drug delivery vehicles for in-eye release in a controllable manner. PMID:26297583

  14. Minimum lens complexity design approach for a free-space macro-optical multichip global interconnection module

    Milojkovic, Predrag; Christensen, Marc P.; Haney, Michael W.

    2000-05-01

    The FAST-Net (Free-space Accelerator for Switching Terabit Networks) concept uses an array of wide field-of-view imaging lenses to realize a high-density shuffle interconnect across an array of smart-pixel integrated circuits. This paper presents a design approach for these lenses that achieves the minimum complexity required to meet the demands of the FAST-Net concept's off-axis multi-chip environment. Generalized eikonals for arbitrary surfaces were examined to determine the performance bounds for the FAST-Net optical system. Then an analysis provided an estimate of 6 for the number of spherical surfaces needed to achieve good optical resolution and distortion performance across an array of 10-micron diameter VCSEL sources that are imaged onto a array of 50-micron wide detectors. A ray trace simulation confirmed this number. Subsequent analysis evaluated the achievable efficient of replacing spherical surfaces with aspherical ones. By exploiting the mismatch between the low numerical aperture VCSELs and relatively higher numerical aperture interconnection optics, it was found that 3 aspherical surfaces could replace 6 spherical surfaces in the FAST-Net system for the specified performance criteria. A lens design that utilizes 3 aspherical surfaces and achieves necessary registration and resolution of the FAST-Net system was determined. The results provide a general framework for the design of wide field-of-view free space interconnection systems that incorporate high-density VCSEL arrays.

  15. Terahertz Artificial Dielectric Lens

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  16. Speaker-Oriented Classroom Acoustics Design Guidelines in the Context of Current Regulations in European Countries

    Pelegrin Garcia, David; Brunskog, Jonas; Rasmussen, Birgit

    2014-01-01

    Most European countries have regulatory requirements or guidelines for reverberation time in classrooms which have the goal of enhancing speech intelligibility and reducing noise levels in schools. At the same time, school teachers suffer frequently from voice problems due to high vocal load...... experienced at work. With the aim of improving working conditions for teachers, this article presents guidelines for classroom acoustics design that meet simultaneously criteria of vocal comfort and speech intelligibility, which may be of use in future discussions for updating regulatory requirements in...

  17. Design and implementation of an efficient acoustically levitated drop reactor for in stillo measurements.

    Field, Christopher R; Scheeline, Alexander

    2007-12-01

    We present the details necessary for building an efficient acoustic drop levitator with reduced electrical power consumption and greater drop stability compared to previous designs. The system is optimized so that the levitated drop may be used as a chemical reactor. By introducing a temperature, pressure, and relative humidity sensor for feedback control of a linear actuator for adjusting resonator length, we have built a completely automated system capable of continuous levitation for extended periods of time. The result is a system capable of portable operation and interfacing with a variety of detection instrumentation for in stillo (in drop) measurements. PMID:18163744

  18. A normalized wave number variation parameter for acoustic black hole design.

    Feurtado, Philip A; Conlon, Stephen C; Semperlotti, Fabio

    2014-08-01

    In recent years, the concept of the Acoustic Black Hole has been developed as an efficient passive, lightweight absorber of bending waves in plates and beams. Theory predicts greater absorption for a higher thickness taper power. However, a higher taper power also increases the violation of an underlying theory smoothness assumption. This paper explores the effects of high taper power on the reflection coefficient and spatial change in wave number and discusses the normalized wave number variation as a spatial design parameter for performance, assessment, and optimization. PMID:25096139

  19. Modeling and design of surface acoustic wave filters and their military applications

    Marija F. Hribšek

    2011-07-01

    Full Text Available The operation principles of surface acoustic wave filters (SAW and materials and technology of their fabrication are presented. A special attention is paid to wide and diverse applications of SAW filters in signal processing, communications and chemical sensors, stressing their military applications. An original method, developed by the authors, for the modeling and prediction of SAW filter characteristics is presented. The abilities of the method are illustrated by the examples of chemical SAW sensors for the detection of warfare chemical agents. The designed and fabricated SAW filter PAT-FPO is the base for the special purpose chemical sensors.

  20. Integrating Real-Time Room Acoustics Simulation into a CAD Modeling Software to Enhance the Architectural Design Process

    Sönke Pelzer; Lukas Aspöck; Dirk Schröder; Michael Vorländer

    2014-01-01

    For architects, real-time 3D visual rendering of CAD-models is a valuable tool. The architect usually perceives the visual appearance of the building interior in a natural and realistic way during the design process. Unfortunately this only emphasizes the role of the visual appearance of a building, while the acoustics often remain disregarded. Controlling the room acoustics is not integrated into most architects’ workflows—due to a lack of tools. The present contribution describes a newly de...

  1. 两个水景剧院的建声设计与音质模拟%Architectural acoustical design and acoustic simulation of two waterscape opera houses

    宋拥民; 章奎生

    2013-01-01

    概述了建于远香湖湖畔的上海嘉定保利大剧院和建于小东海与鹿回头湾交汇处的三亚半岛音乐厅两个水景剧院的建筑概况,重点介绍了保利剧院1500座歌剧厅和半岛音乐厅1300座歌剧厅的音质设计思想、技术指标及建声措施,并对两个水景剧场进行了厅堂音质计算机模拟分析,同时还完成了保利1500座歌剧厅1:10声学缩尺模型试验,最后依据计算机空满场模拟结果对两个剧场的音质进行了初步评估。%An overview on the architectural design of two waterscape theaters is summarized. One named Jiading Poly grand theater built beside Yuanxiang Lake in Shanghai and the other named Sanya Serenity Coast concert hall built on the intersection of small East China Sea and Luhuitou Bay. The main ideas and specifications of acoustics design on 1500-seats opera house in Poly Grand Theater and 1300-seats opera house in Sanya Serenity Coast concert hall are in-troduced in detail, and so are the approaches to making satisfied acoustics. Then acoustics simulation analysis was done in both opera houses with Odeon which is the room acoustics program. Meanwhile, 1/10 scale-model test of 1500-seats opera house was done. Preliminary acoustics evaluations on those two waterscape grand theaters based on computer simulations are given.

  2. Optimization of Capacitive Acoustic Resonant Sensor Using Numerical Simulation and Design of Experiment

    Rubaiyet Iftekharul Haque

    2015-04-01

    Full Text Available Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE. A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM. Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses.

  3. Optimization of capacitive acoustic resonant sensor using numerical simulation and design of experiment.

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  4. An Improved Variable Structure Adaptive Filter Design and Analysis for Acoustic Echo Cancellation

    A. Kar

    2015-04-01

    Full Text Available In this research an advance variable structure adaptive Multiple Sub-Filters (MSF based algorithm for single channel Acoustic Echo Cancellation (AEC is proposed and analyzed. This work suggests a new and improved direction to find the optimum tap-length of adaptive filter employed for AEC. The structure adaptation, supported by a tap-length based weight update approach helps the designed echo canceller to maintain a trade-off between the Mean Square Error (MSE and time taken to attain the steady state MSE. The work done in this paper focuses on replacing the fixed length sub-filters in existing MSF based AEC algorithms which brings refinements in terms of convergence, steady state error and tracking over the single long filter, different error and common error algorithms. A dynamic structure selective coefficient update approach to reduce the structural and computational cost of adaptive design is discussed in context with the proposed algorithm. Simulated results reveal a comparative performance analysis over proposed variable structure multiple sub-filters designs and existing fixed tap-length sub-filters based acoustic echo cancellers.

  5. Integrating Real-Time Room Acoustics Simulation into a CAD Modeling Software to Enhance the Architectural Design Process

    Sönke Pelzer

    2014-04-01

    Full Text Available For architects, real-time 3D visual rendering of CAD-models is a valuable tool. The architect usually perceives the visual appearance of the building interior in a natural and realistic way during the design process. Unfortunately this only emphasizes the role of the visual appearance of a building, while the acoustics often remain disregarded. Controlling the room acoustics is not integrated into most architects’ workflows—due to a lack of tools. The present contribution describes a newly developed plug-in for adding an adequate 3D-acoustics feedback to the architect. To present intuitively the acoustical effect of the current design project, the plug-in uses real-time audio rendering and 3D-reproduction. The room acoustics of the design can be varied by modifying structural shapes as well as by changing the material selection. In addition to the audio feedback, also a visualization of important room acoustics qualities is provided by displaying color-coded maps inside the CAD software.

  6. Through the lens of young people: use of photography in hospital design.

    Coad, Jane

    2016-05-01

    Whilst arts in hospitals have been perceived as therapeutic to patients, this paper will share evidence and research to support that photography and photo-elicitation has an important role in preference and choice about hospital design. The paper will initially draw on studies that used participatory photography in children's hospital design in international settings. PMID:27214415

  7. Design, assembly, and testing of a high-resolution relay lens used for holography with operation at both doubled and tripled Nd:YAG laser wavelengths

    Sorenson, Danny S [Los Alamos National Laboratory; Pazuchanics, Peter D [Los Alamos National Laboratory; Malone, Robert M [NSTEC; Cox, Brian C [NSTEC; Frogget, Brent C [NSTEC; Kaufman, Morris I [NSTEC; Capelle, Gene A [NSTEC/SB; Grover, M [NSTEC/SB; Stevens, Gerald D [NSTEC/SB; Turley, William D [NSTEC/SB

    2009-01-01

    The design and assembly of a nine-element lens that achieves >2000 1p/mm resolution at a 355-nm wavelength (ultraviolet) has been completed. By adding a doublet to this lens system, operation at a 532-nm wavelength (green) with > 1100 1p/mm resolution is achieved. This lens is used with high-power laser light to record holograms of fast-moving ejecta particles from a shocked metal surface located inside a test package. Part of the lens and the entire test package are under vacuum with a 1-cm air gap separation. Holograms have been recorded with both doubled and tripled Nd:YAG laser light. The UV operation is very sensitive to the package window's tilt. If this window is tilted by more than 0.1 degrees, the green operation performs with better resolution than that of the UV operation. The setup and alignment are performed with green light, but the dynamic recording can be done with either UV light or green light. A resolution plate can be temporarily placed inside the test package so that a television microscope located beyond the hologram position can archive images of resolution patterns that prove that the calibration wires., interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens are presented. Resolution variation across the 12-mm field of view and throughout the 5-mm depth of field is discussed for both wavelengths.

  8. Responsive acoustic surfaces

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton;

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design for the...... acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design was...... simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  9. Wood lens design philosophy based on a binary additive manufacturing technique

    Marasco, Peter L.; Bailey, Christopher

    2016-04-01

    Using additive manufacturing techniques in optical engineering to construct a gradient index (GRIN) optic may overcome a number of limitations of GRIN technology. Such techniques are maturing quickly, yielding additional design degrees of freedom for the engineer. How best to employ these degrees of freedom is not completely clear at this time. This paper describes a preliminary design philosophy, including assumptions, pertaining to a particular printing technique for GRIN optics. It includes an analysis based on simulation and initial component measurement.

  10. Impact of flow induced vibration acoustic loads on the design of the Laguna Verde Unit 2 steam dryer

    Industry experience with Boiling Water Reactors (BWRs) has shown that increasing the steam flow through the main steam lines (MSLs) to implement an extended power up rate (EPU) may lead to amplified acoustic loads on the steam dryer, which may negatively affect the structural integrity of the component. The source of these acoustic loads has been found to be acoustic resonance of the side branches on the MSLs, specifically, coupling of the vortex shedding frequency and natural acoustic frequency of safety relief valves (SRVs). The resonance that results from this coupling can contribute significant acoustic energy into the MSL system, which may propagate upstream into the reactor pressure vessel steam dome and drive structural vibration of steam dryer components. This can lead to high-cycle fatigue issues. Lock-in between the vortex shedding frequency and SRV natural frequency, as well as the ability for acoustic energy to propagate into the MSL system, are a function of many things, including the plant operating conditions, geometry of the MSL/SRV junction, and placement of SRVs with respect to each other on the MSLs. Comision Federal de Electricidad and Westinghouse designed, fabricated, and installed acoustic side branches (ASBs) on the MSLs which effectively act in the system as an energy absorber, where the acoustic standing wave generated in the side-branch is absorbed and dissipated inside the ASB. These ASBs have been very successful in reducing the amount of acoustic energy which propagates into the steam dome. In addition, modifications to the Laguna Verde Nuclear Power Plant Unit 2 steam dryer have been completed to reduce the stress levels in critical locations in the dryer. The objective of this paper is to describe the acoustic side branch concept and the design iterative processes that were undertaken at Laguna Verde Unit 2 to achieve a steam dryer design that meets the guidelines of the American Society of Mechanical Engineers, Boiler and Pressure

  11. Impact of flow induced vibration acoustic loads on the design of the Laguna Verde Unit 2 steam dryer

    Forsyth, D. R.; Wellstein, L. F.; Theuret, R. C.; Han, Y.; Rajakumar, C. [Westinghouse Electric Company LLC, Cranberry Township, PA 16066 (United States); Amador C, C.; Sosa F, W., E-mail: forsytdr@westinghouse.com [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Km 42.5 Carretera Cardel-Nautla, 91680 Alto Lucero, Veracruz (Mexico)

    2015-09-15

    Industry experience with Boiling Water Reactors (BWRs) has shown that increasing the steam flow through the main steam lines (MSLs) to implement an extended power up rate (EPU) may lead to amplified acoustic loads on the steam dryer, which may negatively affect the structural integrity of the component. The source of these acoustic loads has been found to be acoustic resonance of the side branches on the MSLs, specifically, coupling of the vortex shedding frequency and natural acoustic frequency of safety relief valves (SRVs). The resonance that results from this coupling can contribute significant acoustic energy into the MSL system, which may propagate upstream into the reactor pressure vessel steam dome and drive structural vibration of steam dryer components. This can lead to high-cycle fatigue issues. Lock-in between the vortex shedding frequency and SRV natural frequency, as well as the ability for acoustic energy to propagate into the MSL system, are a function of many things, including the plant operating conditions, geometry of the MSL/SRV junction, and placement of SRVs with respect to each other on the MSLs. Comision Federal de Electricidad and Westinghouse designed, fabricated, and installed acoustic side branches (ASBs) on the MSLs which effectively act in the system as an energy absorber, where the acoustic standing wave generated in the side-branch is absorbed and dissipated inside the ASB. These ASBs have been very successful in reducing the amount of acoustic energy which propagates into the steam dome. In addition, modifications to the Laguna Verde Nuclear Power Plant Unit 2 steam dryer have been completed to reduce the stress levels in critical locations in the dryer. The objective of this paper is to describe the acoustic side branch concept and the design iterative processes that were undertaken at Laguna Verde Unit 2 to achieve a steam dryer design that meets the guidelines of the American Society of Mechanical Engineers, Boiler and Pressure

  12. Design Realization and Performance Evaluation of an Acoustic Echo Cancellation (AEC in Hands-Free Communications Using Recursive Adaptive Algorithm

    Azeddine Wahbi

    2015-06-01

    Full Text Available Nowadays, in the field of communications, AEC (acoustic echo cancellation is truly essential with respect to the quality of multimedia transmission. In this paper, we designed and developed an efficient AEC based on adaptive filters to improve quality of service in telecommunications against the phenomena of acoustic echo, which is indeed a problem in hands-free communications. The main advantage of the proposed algorithm is its capacity of tracking non-stationary signals such as acoustic echo. In this work the acoustic echo cancellation (AEC is modeled using a digital signal processing technique especially Simulink Blocksets. The algorithm’s code is generated in Matlab Simulink programming environment. At simulation level, results of simulink implementation prove that module behavior is realistic when it comes to cancellation of echo in hands free communication using adaptive algorithm. Results obtained with our algorithm in terms of ERLE criteria are confronted to IUT-T recommendation G.168.

  13. Design and performance of a 30 KV electron gun with ten independent cathodes & a magnetic lens.

    Rudys, Joseph Matthew; Reed, Kim Warren

    2006-08-01

    Measurements on a 30 kV electron gun with ten independent cathodes, operating in a 6.5 Tesla (T) magnetic field are presented. An earlier paper covered the design of this electron gun [1]. Experimental results are compared to model predictions. Beam current is compared to theoretical space charge limited flow.

  14. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ∼1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 61 and 6111 vibronic levels in the S1 state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1′) REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62 271 ± 3 cm−1). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique

  15. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments.

    Qu, Zehua; Li, Chunsheng; Qin, Zhengbo; Zheng, Xianfeng; Yao, Guanxin; Zhang, Xianyi; Cui, Zhifeng

    2015-06-01

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ∼1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 6(1) and 6(1)1(1) vibronic levels in the S1 state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1') REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62,271 ± 3 cm(-1)). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique. PMID:26133827

  16. Design and performance of acoustic planar array antenna for Doppler sodar

    A.Kamalakumari

    2012-09-01

    Full Text Available The remote probing of the thermal structure and the wind velocity in the lower atmosphere requires highly directive antennas, which should have a half-power beam width of about ±10° (3-dB points, a 90°-sidelobe suppression of at least 40 dB, little volume reverberation, low wind sensitivity, and be made of weatherproofmaterial. In this paper, various off-axis planar antennas have been built and acoustically evaluated the design aspects, measured results and field patterns of an 8x8 acoustic planar array antennas are described. Tweeter elements are arranged in a planar geometry and are capable of transmitting vertical polarization when placed nearly horizontal, are appropriate for the sodar applications. The performance of 8x8 planar antennas are tested experimentally for the frequencies from 1.8KHz to 4KHz at elevation angles ranging between 0 to 180°.The experimental results, as well as the measured beam widths and field patterns of this antennas, are presented.

  17. Design and analysis of air acoustic vector-sensor configurations for two-dimensional geometry.

    Wajid, Mohd; Kumar, Arun; Bahl, Rajendar

    2016-05-01

    Acoustic vector-sensors (AVS) have been designed using the P-P method for different microphone configurations. These configurations have been used to project the acoustic intensity on the orthogonal axes through which the direction of arrival (DoA) of a sound source has been estimated. The analytical expressions for the DoA for different microphone configurations have been derived for two-dimensional geometry. Finite element method simulation using COMSOL-Multiphysics has been performed, where the microphone signals for AVS configurations have been recorded in free field conditions. The performance of all the configurations has been evaluated with respect to angular error and root-mean-square angular error. The simulation results obtained with ideal geometry for different configurations have been corroborated experimentally with prototype AVS realizations and also compared with microphone-array method, viz., Multiple Signal Classification and Generalized Cross Correlation. Experiments have been performed in an anechoic room using different prototype AVS configurations made from small size microphones. The DoA performance using analytical expressions, simulation studies, and experiments with prototype AVS in anechoic chamber are presented in the paper. The square and delta configurations are found to perform better in the absence and presence of noise, respectively. PMID:27250174

  18. Acoustic Evaluation of Single Gutters with Different Design Configurations alongside Highways

    SAMANEH MOMEN-BELLAHFARD

    2015-10-01

    Full Text Available  Environmental noise pollution is among the most urban problems which can be caused due to real sources like traffic, train and virtual sources provided by rigid surfaces. One of the urban structures in which can perform as a virtual noise source are the installed gutters alongside highways. These structures are mostly used to pass the wastewater or the rainfall. In this research, the acoustical performance of a gutter when the receivers are located on the top surface of gutter or in its shadow zone is investigated. To compute the acoustical efficiency of gutters, a 2D Boundary Element Method (BEM is used. Investigation on the top surface of a simple gutter has shown that the total sound pressure has been changed and results in some disturbance. Various shapes have been studied to decline such disturbance. It was found that sound pressure of the model with curved basement was scattered steadier and the sound pressure for gutter models with wide basement was lower than the ones with narrow basement. Efficiency of some designed models was also compared in the shadow zone. Increase in depth and wide of gutter models either on the top or bottom surface has enhanced the performance of simple reference model. Considering the insertion loss computations, the amount of overall improvement in models with higher depths was more than widen models because of shifting effective performance toward lower frequencies.

  19. Acoustic Design in Urban Development : analysis of urban soundscapes and acoustic ecology research in New York City

    Pontén, Emeli

    2010-01-01

    The world is urbanizing rapidly with more than half of the global population now living in cities. Improving urban environments for the well-being of the increasing number of urban citizens is becoming one of the most important challenges of the 21st century. Even though it is common that city planners have visions of a ’good urban milieu’, those visions are concerning visual aesthetics or practical matters. The qualitative perspective of sound, such as sonic diversity and acoustic ecology ar...

  20. A debugging system for azimuthally acoustic logging tools based on modular and hierarchical design ideas

    Zhang, K.; Ju, X. D.; Lu, J. Q.; Men, B. Y.

    2016-08-01

    On the basis of modular and hierarchical design ideas, this study presents a debugging system for an azimuthally sensitive acoustic bond tool (AABT). The debugging system includes three parts: a personal computer (PC), embedded front-end machine and function expansion boards. Modular and hierarchical design ideas are conducted in all design and debug processes. The PC communicates with the front-end machine via the Internet, and the front-end machine and function expansion boards connect each other by the extended parallel bus. In this method, the three parts of the debugging system form stable and high-speed data communication. This study not only introduces the system-level debugging and sub-system level debugging of the tool but also the debugging of the analogue signal processing board, which is important and greatly used in logging tools. Experiments illustrate that the debugging system can greatly improve AABT verification and calibration efficiency and that, board-level debugging can examine and improve analogue signal processing boards. The design thinking is clear and the design structure is reasonable, thus making it easy to extend and upgrade the debugging system.

  1. Optics design for J-TEXT ECE imaging with field curvature adjustment lens

    Zhu, Y.; Zhao, Z.; Liu, W. D.; Xie, J., E-mail: jlxie@ustc.edu.cn [School of Physics, University of Science and Technology of China, Anhui 230026 (China); Hu, X.; Muscatello, C. M.; Domier, C. W.; Luhmann, N. C.; Chen, M.; Ren, X. [University of California at Davis, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Zhuang, G.; Yang, Z. [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-11-15

    Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas. Of particular importance has been microwave electron cyclotron emission imaging (ECEI) for imaging T{sub e} fluctuations. Key to the success of ECEI is a large Gaussian optics system constituting a major portion of the focusing of the microwave radiation from the plasma to the detector array. Both the spatial resolution and observation range are dependent upon the imaging optics system performance. In particular, it is critical that the field curvature on the image plane is reduced to decrease crosstalk between vertical channels. The receiver optics systems for two ECEI on the J-TEXT device have been designed to ameliorate these problems and provide good performance with additional field curvature adjustment lenses with a meniscus shape to correct the aberrations from several spherical surfaces.

  2. Optics design for J-TEXT ECE imaging with field curvature adjustment lens.

    Zhu, Y; Zhao, Z; Liu, W D; Xie, J; Hu, X; Muscatello, C M; Domier, C W; Luhmann, N C; Chen, M; Ren, X; Tobias, B J; Zhuang, G; Yang, Z

    2014-11-01

    Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas. Of particular importance has been microwave electron cyclotron emission imaging (ECEI) for imaging Te fluctuations. Key to the success of ECEI is a large Gaussian optics system constituting a major portion of the focusing of the microwave radiation from the plasma to the detector array. Both the spatial resolution and observation range are dependent upon the imaging optics system performance. In particular, it is critical that the field curvature on the image plane is reduced to decrease crosstalk between vertical channels. The receiver optics systems for two ECEI on the J-TEXT device have been designed to ameliorate these problems and provide good performance with additional field curvature adjustment lenses with a meniscus shape to correct the aberrations from several spherical surfaces. PMID:25430267

  3. A broadband transformation-optics metasurface lens

    Wan, Xiang; Xiang Jiang, Wei; Feng Ma, Hui; Jun Cui, Tie, E-mail: tjcui@seu.edu.cn [State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096 (China)

    2014-04-14

    We present a transformational metasurface Luneburg lens based on the quasi-conformal mapping method, which has weakly anisotropic constitutive parameters. We design the metasurface lens using inhomogeneous artificial structures to realize the required surface refractive indexes. The transformational metasurface Luneburg lens is fabricated and the measurement results demonstrate very good performance in controlling the radiated surface waves.

  4. Recent multi-purpose hall designs in Denmark with physically variable acoustics

    Gade, Anders Christian

    1999-01-01

    This paper describes two recent Danish multi-purpose hall designs, in which acoustic variability has been accomplished in different ways: through variable absorption and variable volume, respectively. The different approaches were chosen in order to insure that not only reverberation time (T......) and so clarity (C), but also the strength parameter (G) could be varied in a favorable direction in view of the prescribed uses of the halls. The hall with variable absorption is the assembly hall in the new extension to the Royal Library in Copenhagen to open in fall 1999. This hall will seat 600 people...... and be used for chamber music concerts, symphony orchestra rehearsals, and amplified speech. For the latter two functions, a reduction in G along with reduction in T was considered favorable. The hall with variable volume is the recently opened Esbjerg Musikhus seating 1100 and equipped with a full stage...

  5. SU-E-CAMPUS-T-02: Exploring Radiation Acoustics CT Dosimeter Design Aspects for Proton Therapy

    Purpose: Investigate the design aspects and imaging dose capabilities of the Radiation Acoustics Computed Tomography (RA CT) dosimeter for Proton induced acoustics, with the objective to characterize a pulsed pencil proton beam. The focus includes scanner geometry, transducer array, and transducer bandwidth on image quality. Methods: The geometry of the dosimeter is a cylindrical water phantom (length 40cm, radius 15cm) with 71 ultrasound transducers placed along the length and end of the cylinder to achieve a weighted set of projections with spherical sampling. A 3D filtered backprojection algorithm was used to reconstruct the dosimetric images and compared to MC dose distribution. First, 3D Monte Carlo (MC) Dose distributions for proton beam energies (range of 12cm, 16cm, 20cm, and 27cm) were used to simulate the acoustic pressure signal within this scanner for a pulsed proton beam of 1.8x107 protons, with a pulse width of 1 microsecond and a rise time of 0.1 microseconds. Dose comparison within the Bragg peak and distal edge were compared to MC analysis, where the integrated Gaussian was used to locate the 50% dose of the distal edge. To evaluate spatial fidelity, a set of point sources within the scanner field of view (15×15×15cm3) were simulated implementing a low-pass bandwidth response function (0 to 1MHz) equivalent to a multiple frequency transducer array, and the FWHM of the point-spread-function determined. Results: From the reconstructed images, RACT and MC range values are within 0.5mm, and the average variation of the dose within the Bragg peak are within 2%. The spatial resolution tracked with transducer bandwidth and projection angle sampling, and can be kept at 1.5mm. Conclusion: This design is ready for fabrication to start acquiring measurements. The 15 cm FOV is an optimum size for imaging dosimetry. Currently, simulations comparing transducer sensitivity, bandwidth, and proton beam parameters are being evaluated to assess signal-to-noise

  6. Lens Model

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of probabil......Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of...... probabilistic functionalism, and concerns the environment and the mind, and adaptation by the latter to the former. This entry is about the lens model, and probabilistic functionalism more broadly. Focus will mostly be on firms and their employees, but, to fully appreciate the scope, we have to keep in mind the...

  7. Principles for the design and calibration of radiation protection dosemeters for operational and protection quantities for eye lens dosimetry

    The work package two of the ORAMED project-Collaborative Project (2008-2011) supported by the European Commission within its seventh Framework Programme-is devoted to the study of the eye lens dosimetry. A first approach is to implement the use of Hp(3) by providing new sets of conversion coefficients and well suited calibration and type test procedures. This approach is presented in other papers in the proceedings of this conference. Taking into account that the eye lens is an organ close to the surface of the body, another approach would be to directly estimate the absorbed dose to the eye lens, Dlens,est through a special calibration procedure although this quantity is not directly measurable. This paper is a methodological paper that tries to identify the critical aspects of a dosimetry in terms of Dlens. (authors)

  8. Acoustic dispersive prism

    Hussein Esfahlani; Sami Karkar; Herve Lissek; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic ...

  9. Modern lens antennas for communications engineering

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  10. Design and aero-acoustic analysis of a counter-rotating wind turbine

    Agrawal, Vineesh V.

    Wind turbines have become an integral part of the energy business because they are one of the most economical and reliable sources of renewable energy. Conventional wind turbines are capable of capturing less than half of the energy present in the wind. Hence, to make the wind turbines more efficient, it is important to increase their performance. A horizontal axis wind turbine with multiple rotors is one concept that can achieve a higher power conversion rate. Also, a concern for wind energy is the noise generated by wind turbines. Hence, an investigation into the acoustic behavior of a multi-rotor horizontal axis wind turbine is required. In response to the need of a wind turbine design with higher power coefficient, a unique design of a counter-rotating horizontal axis wind turbine (CR-HAWT) is proposed. The Blade Element Momentum (BEM) theory is used to aerodynamically design the blades of the two rotors. Modifications are made to the BEM theory to accommodate the interaction of the two rotors. The tower effect on the noise generation of the downwind rotor is investigated. Predictions are made for the total noise generated by the wind turbine at its design operating conditions. A total power coefficient of 65.2% is predicted for the proposed CR-HAWT design. A low tip speed ratio is chosen to minimize the noise generation. The aeroacoustic analysis of the CR-HAWT shows that the noise generated at its design operating conditions is within an acceptable range. Thus, the CR-HAWT is predicted to be a quiet wind turbine with a high power coefficient, making it highly desirable for small wind turbine applications.

  11. Joint Design of Spherical Microphone and Loudspeaker Arrays for Room Acoustic Analysis

    Morgenstern, Hai; Rafaely, Boaz; Noisternig, Markus

    2015-01-01

    Spherical microphone arrays (SMAs) and spherical loudspeaker arrays (SLAs) have been studied separately for directional sound recording and radiation, respectively, and for room acoustic analysis. The use of configurations comprised of both a SLA and a SMA, referred to as acoustic multiple-input multiple-output (MIMO) systems, can potentially facilitate an additional spatial analysis of room acoustics due to the added spatial diversity they provide. When using spherical arrays, robustness to ...

  12. Design And Simulation Of An Acoustic Echo Cancellation System For Hand-Free Telecommunication

    Ein Gyin Pwint

    2015-06-01

    Full Text Available Abstract Acoustic echo cancellation is a common occurrence in todays telecommunication systems. The signal interference caused by acoustic echo is distracting to users and causes a reduction in the quality of the communication. This paper is implementing the overall system of acoustic echo cancellation system using LMS and NLMS algorithms for adaptive filter normalized cross correlation NCC algorithm double talk detector. The result of echo return loss enhancement ERLE and mean squared error MSE which show that how much the amount of echo signal cancelled and the amount of residual error signal for cancelling acoustic echo cancellation on a PC with the help of the MATLAB software.

  13. Acoustic metamaterials for new two-dimensional sonic devices

    It has been shown that two-dimensional arrays of rigid or fluidlike cylinders in a fluid or a gas define, in the limit of large wavelengths, a class of acoustic metamaterials whose effective parameters (sound velocity and density) can be tailored up to a certain limit. This work goes a step further by considering arrays of solid cylinders in which the elastic properties of cylinders are taken into account. We have also treated mixtures of two different elastic cylinders. It is shown that both effects broaden the range of acoustic parameters available for designing metamaterials. For example, it is predicted that metamaterials with perfect matching of impedance with air are now possible by using aerogel and rigid cylinders equally distributed in a square lattice. As a potential application of the proposed metamaterial, we present a gradient index lens for airborne sound (i.e. a sonic Wood lens) whose functionality is demonstrated by multiple scattering simulations

  14. Acoustic metamaterials for new two-dimensional sonic devices

    Torrent, Daniel; Sanchez-Dehesa, Jose [Wave Phenomena Group, Department of Electronic Engineering, Polytechnic University of Valencia, C/Camino de Vera sn, E-46022 Valencia (Spain)

    2007-09-15

    It has been shown that two-dimensional arrays of rigid or fluidlike cylinders in a fluid or a gas define, in the limit of large wavelengths, a class of acoustic metamaterials whose effective parameters (sound velocity and density) can be tailored up to a certain limit. This work goes a step further by considering arrays of solid cylinders in which the elastic properties of cylinders are taken into account. We have also treated mixtures of two different elastic cylinders. It is shown that both effects broaden the range of acoustic parameters available for designing metamaterials. For example, it is predicted that metamaterials with perfect matching of impedance with air are now possible by using aerogel and rigid cylinders equally distributed in a square lattice. As a potential application of the proposed metamaterial, we present a gradient index lens for airborne sound (i.e. a sonic Wood lens) whose functionality is demonstrated by multiple scattering simulations.

  15. Experimental study on acoustic subwavelength imaging of holey-structured metamaterials by resonant tunneling.

    Su, Haijing; Zhou, Xiaoming; Xu, Xianchen; Hu, Gengkai

    2014-04-01

    A holey-structured metamaterial is proposed for near-field acoustic imaging beyond the diffraction limit. The structured lens consists of a rigid slab perforated with an array of cylindrical holes with periodically modulated diameters. Based on the effective medium approach, the structured lens is characterized by multilayered metamaterials with anisotropic dynamic mass, and an analytic model is proposed to evaluate the transmission properties of incident evanescent waves. The condition is derived for the resonant tunneling, by which evanescent waves can completely transmit through the structured lens without decaying. As an advantage of the proposed lens, the imaging frequency can be modified by the diameter modulation of internal holes without the change of the lens thickness in contrast to the lens due to the Fabry-Pérot resonant mechanism. In this experiment, the lens is assembled by aluminum plates drilled with cylindrical holes. The imaging experiment demonstrates that the designed lens can clearly distinguish two sources separated in the distance below the diffraction limit at the tunneling frequency. PMID:25234968

  16. From Architectural Acoustics to Acoustical Architecture Using Computer Simulation

    Schmidt, Anne Marie Due; KIRKEGAARD, Poul Henning

    2005-01-01

    Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in architectural acoustics and the emergence of room acoustic simulation programmes with considerable potential, it is now possible to subjectively analyse and evaluate acoustic properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to inve...

  17. Design factors of intravascular dual frequency transducers for super-harmonic contrast imaging and acoustic angiography.

    Ma, Jianguo; Martin, K Heath; Li, Yang; Dayton, Paul A; Shung, K Kirk; Zhou, Qifa; Jiang, Xiaoning

    2015-05-01

    Imaging of coronary vasa vasorum may lead to assessment of the vulnerable plaque development in diagnosis of atherosclerosis diseases. Dual frequency transducers capable of detection of microbubble super-harmonics have shown promise as a new contrast-enhanced intravascular ultrasound (CE-IVUS) platform with the capability of vasa vasorum imaging. Contrast-to-tissue ratio (CTR) in CE-IVUS imaging can be closely associated with low frequency transmitter performance. In this paper, transducer designs encompassing different transducer layouts, transmitting frequencies, and transducer materials are compared for optimization of imaging performance. In the layout selection, the stacked configuration showed superior super-harmonic imaging compared with the interleaved configuration. In the transmitter frequency selection, a decrease in frequency from 6.5 MHz to 5 MHz resulted in an increase of CTR from 15 dB to 22 dB when receiving frequency was kept constant at 30 MHz. In the material selection, the dual frequency transducer with the lead magnesium niobate-lead titanate (PMN-PT) 1-3 composite transmitter yielded higher axial resolution compared to single crystal transmitters (70 μm compared to 150 μm pulse length). These comparisons provide guidelines for the design of intravascular acoustic angiography transducers. PMID:25856384

  18. Acoustic force mapping in a hybrid acoustic-optical micromanipulation device supporting high resolution optical imaging.

    Thalhammer, Gregor; McDougall, Craig; MacDonald, Michael Peter; Ritsch-Marte, Monika

    2016-04-12

    Many applications in the life-sciences demand non-contact manipulation tools for forceful but nevertheless delicate handling of various types of sample. Moreover, the system should support high-resolution optical imaging. Here we present a hybrid acoustic/optical manipulation system which utilizes a transparent transducer, making it compatible with high-NA imaging in a microfluidic environment. The powerful acoustic trapping within a layered resonator, which is suitable for highly parallel particle handling, is complemented by the flexibility and selectivity of holographic optical tweezers, with the specimens being under high quality optical monitoring at all times. The dual acoustic/optical nature of the system lends itself to optically measure the exact acoustic force map, by means of direct force measurements on an optically trapped particle. For applications with (ultra-)high demand on the precision of the force measurements, the position of the objective used for the high-NA imaging may have significant influence on the acoustic force map in the probe chamber. We have characterized this influence experimentally and the findings were confirmed by model simulations. We show that it is possible to design the chamber and to choose the operating point in such a way as to avoid perturbations due to the objective lens. Moreover, we found that measuring the electrical impedance of the transducer provides an easy indicator for the acoustic resonances. PMID:27025398

  19. Design of an Acoustic Probe to Measure Otoacoustic Emissions Below 0.5 kHz

    Christensen, Anders Tornvig; Ordoñez, Rodrigo; Hammershøi, Dorte

    2015-01-01

    Our ability to hear is reflected in low-level acoustic signals emitted from the ear. These otoacoustic emissions (OAEs) can be measured with an acoustic probe assembly coupling one or more small loudspeakers and microphones into the sealed ear canal. The electroacoustic instrumentation of...

  20. Luneburg and flat lens based on graded photonic crystal

    Liu, Wei; Sun, Xiaohong; Gao, Minglei; Wang, Shuai

    2016-04-01

    Square-lattice graded photonic crystals employed for designing Luneburg and Flat Lens is presented. Comparable simulation of the Luneburg lens with TE and TM polarizations predicts that TM lens possesses of enlarged transmission bandwidth and strengthened focusing ability, in comparison with TE lens. As a typical simplified counterpart, the evolution of focusing intensity and numerical aperture of the flat lens is achieved. What is more, those Luneburg and Flat Lens can withstand imperfect gradients in structure design. This will provide a guidance to produce a high quality focusing lens with small size, short focal length and large numerical aperture applied in the integrated photonic devices.

  1. Towards a reference cavitating vessel Part III—design and acoustic pressure characterization of a multi-frequency sonoreactor

    Wang, Lian; Memoli, Gianluca; Hodnett, Mark; Butterworth, Ian; Sarno, Dan; Zeqiri, Bajram

    2015-08-01

    A multi-frequency cavitation vessel (RV-multi) has been commissioned at the National Physical Laboratory (NPL, UK), with the aim of establishing a standard source of acoustic cavitation in water, with reference to which details of the cavitation process can be studied and cavitation measurement techniques evaluated. The vessel is a cylindrical cavity with a maximum capacity up to 17 L, and is designed to work at six frequency ranges, from 21 kHz to 136 kHz, under controlled temperature conditions. This paper discusses the design of RV-multi and reports experiments carried out to establish the reproducibility of the acoustic pressure field established within the vessel and its operating envelope, including sensitivity to aspects such as water depth and temperature. The acoustic field distribution was determined along the radial and depth directions within the vessel using a miniature hydrophone, for two input voltage levels under low power transducer excitation conditions (e.g. below the cavitation threshold). Particular care was taken in determining peak acoustic pressure locations, as these are critical for accompanying cavitation studies. Perturbations of the vessel by the measuring hydrophone were also monitored with a bottom-mounted pressure sensor.

  2. A new sparse design method on phased array-based acoustic emission sensor for partial discharge detection

    The acoustic detecting performance of a partial discharge (PD) ultrasonic sensor array can be improved by increasing the number of array elements. However, it will increase the complexity and cost of the PD detection system. Therefore, a sparse sensor with an optimization design can be chosen to ensure good acoustic performance. In this paper, first, a quantitative method is proposed for evaluating the acoustic performance of a square PD ultrasonic array sensor. Second, a method of sparse design is presented to combine the evaluation method with the chaotic monkey algorithm. Third, an optimal sparse structure of a 3 × 3 square PD ultrasonic array sensor is deduced. It is found that, under different sparseness and sparse structure, the main beam width of the directivity function shows a small variation, while the sidelobe amplitude shows a bigger variation. For a specific sparseness, the acoustic performance under the optimal sparse structure is close to that using a full array. Finally, some simulations based on the above method show that, for certain sparseness, the sensor with the optimal sparse structure exhibits superior positioning accuracy compared to that with a stochastic one. The sensor array structure may be chosen according to the actual requirements for an actual engineering application. (paper)

  3. CONSIDERATION OF THE CRITERIA OF SIM-ILARITY TO CREATE NEW DESIGNS OF ACOUSTIC-MAGNETIC DEVICES INTENDED TO BE USED IN HYDROPONIC STATIONS

    Korzhakov A. V.; Korzhakova S. A.

    2014-01-01

    The article contains the results of theoretical research of the criteria of similarity of acoustic-magnetic device intended for the use of new designs in hydroponic stations. Calculation of the electromagnetic component of the acoustic-magnetic device that has four interrelated path has been made

  4. Camera design of 4P slim 8 megapixel lens%4P超薄800万像素镜头设计

    丛海芳

    2014-01-01

    针对手机镜头很难同时实现高成像质量和短总长的实际问题,通过对初始结构进行优化设计,得到一款全部采用光学塑料为透镜材料的超薄手机镜头。镜头采用四片式结构,光阑位于镜头前方,镜片全部采用偶次非球面。该镜头总长4.49 mm,F数为2.4,视场角为65.5°,焦距为3.71 mm,在探测器Nyquist频率处MTF均大于0.14,在半Nyquist频率处MTF均大于0.46,且畸变小于1.5%。光学系统各视场的均方根半径小于3.5μm。采用索尼公司的IMX111型号CMOS探测器,最大分辨率为3264×2448。通过模拟计算,得到该手机镜头的离焦量为144μm。通过调焦,可以在物距大于10 cm时,得到像质较好的图像。通过灵敏度分析,镜头公差满足加工要求。该镜头设计长度较短,采用非球面塑料透镜,生产成本较低,成像性能良好,满足手机镜头的使用要求。%To achieve good performance with short length, an ultra-thin cell phone lens was designed with optical plastic as lens material by optimizing the initial structure. The lens included four pieces with even aspheric, and the aperture was placed in front. The length of the lens was 4.49 mm, the F number was 2.4, the viewing angle was 65.5° , and the focal length was 3.71 mm. The MTF at the Nyquist frequency and half-Nyquist frequency of the detector was respectively greater than 0.14 and 0.46 and distortion of the lens was less than 1.5%. The RMS radius of different fields was less than 3.5μm. The CMOS sensor IMX111 from SONY was adopted, and the maximum resolution was 3 264 ×2 488. By simulation, the defocusing amount of the cell phone was 144μm. By focusing, high quality images can be obtained when the object distance was greater than 10 cm. Through the sensitivity analysis, the tolerance of the lens met the processing requirements. With short length and aspherical plastic lens, the production cost is low, the imaging

  5. Design and analyses of an ultra-thin flat lens for wave front shaping in the visible

    Huang, Kai; Li, Yiyan; Tian, Xuelong; Zeng, Dajun; Gao, Xueli

    2015-12-01

    An ultra-thin flat lens is proposed for focusing circularly polarized light in the visible range. Anisotropic C-shaped nanoantennas with phase discontinuities are used to form the metasurface of the lens. The phase response of the C-shaped nanoantennas can be manipulated by simply rotating the angle of the unit nanoantenna. A 600 nm incident circularly polarized light is focused by the proposed techniques. Good agreements are observed by using our MoM and a commercial FDTD software package. The computation time spent by using MoM is approximately 10-100 times smaller than using FDTD. All the results show the proposed nanoantenna array has a great potential for nanoscale optical microscopy, solar cell energy conversion enhancement, as well as integrated optical circuits.

  6. The lens and source of the optical Einstein ring gravitational lens ER 0047-2808

    Wayth, Randall B.; Warren, Stephen J.; Lewis, Geraint F.; Hewett, Paul C.

    2004-01-01

    (Abridged) We perform a detailed analysis of the optical gravitational lens ER 0047-2808 imaged with WFPC2 on the Hubble Space Telescope. Using software specifically designed for the analysis of resolved gravitational lens systems, we focus on how the image alone can constrain the mass distribution in the lens galaxy. We find the data are of sufficient quality to strongly constrain the lens model with no a priori assumptions about the source. Using a variety of mass models, we find statistica...

  7. Bionic intraocular lens with variable focus and integrated structure

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei; Xiang, Ke

    2015-10-01

    This paper proposes a bionic accommodating intraocular lens (IOL) for ophthalmic surgery. The designed lens has a solid-liquid mixed integrated structure, which mainly consists of a support ring, elastic membrane, rigid lens, and optical liquid. The lens focus can be adjusted through the deformation of the lens front surface when compressed. The integrated structure of the IOL is presented, as well as a detailed description of the lens materials and fabrication process. Images under different radial pressures are captured, and the lens deformation process, accommodating range, density, and optical property are analyzed. The designed lens achieves a 14.6 D accommodating range under a radial pressure of 51.4 mN and a 0.24 mm alteration of the lens outer radius. The deformation property of the lens matches well with the characteristic of the eye and shows the potential to help patients fully recover their vision accommodation ability after the cataract surgery.

  8. LED路灯的二次光学透镜设计%General design of secondary optical lens in LED lighting

    陈加琦; 邹念育; 张云翠; 贺晓阳; 李德胜

    2012-01-01

    In view of the diversity and difficulty of the demand of street lighting, based on the mapping principle of the polar candela distribution, used transmission optical design methods, learn from traditional street design method, contrary to single powerful white LED, in line with its specific luminous distribution parameters, a kind of secondary optical lens had been designed. Results show that it is possible to design a correspondence secondary optical lens if given the parameters of the LED source. The designed lens can covert the Lambert distribution of the LED to Bat wing distribution, on other word, change the round light spot to rectangle light spot. Also very high light output efficiency and nearly 1 : 2 of the aspect ratio can be got simultaneously. Compared with the similar design, using the most advanced light source, this design have achieve the national standard as well as reducing design complexity. This method can be used to design LED street lighting.%鉴于道路照明需求的多样性和复杂性,基于配光曲线映射原理,运用透射光学设计手段,借鉴传统路灯设计方法,针对单颗大功率白光LED,根据其特有的配光特性参数设计了一种新颖的二次光学透镜.该透镜实现了将LED的郎伯型配光转换为蝙蝠翼型配光,将圆形光斑转换为矩形光斑,同时可以达到很高的光输出效率和近似1:2的长宽比.与同类设计相比,达到国家道路照明标准,同时降低了设计复杂度,可应用于LED路灯设计.

  9. Analysis, Design, and Evaluation of Acoustic Feedback Cancellation Systems for Hearing Aids

    Guo, Meng

    2013-01-01

    Acoustic feedback problems occur when the output loudspeaker signal of an audio system is partly returned to the input microphone via an acoustic coupling through the air. This problem often causes significant performance degradations in applications such as public address systems and hearing aids....... In the worst case, the audio system becomes unstable and howling occurs. In this work, first we analyze a general multiple microphone audio processing system, where a cancellation system using adaptive filters is used to cancel the effect of acoustic feedback. We introduce and derive an accurate...... estimation problem in acoustic feedback cancellation for hearing aids. It utilizes a probe noise signal which is generated with a specific characteristic so that it can facilitate an unbiased adaptive filter estimation with fast tracking of feedback path variations/changes despite its low signal level. We...

  10. Acoustic evaluation and adjustment of an open-plan office through architectural design and noise control.

    Passero, Carolina Reich Marcon; Zannin, Paulo Henrique Trombetta

    2012-11-01

    Arranging office space into a single open room offers advantages in terms of easy exchange of information and interaction among coworkers, but reduces privacy and acoustic comfort. Thus, the purpose of this work was to evaluate the acoustic quality of a real open-plan office and to propose changes in the room to improve the acoustic conditioning of this office. The computational model of the office under study was calibrated based on RT and STI measurements. Predictions were made of the RT and STI, which generated the radius of distraction r(D), and the rate of spatial decay of sound pressure levels per distance doubling DL(2) in the real conditions of the office and after modifications of the room. The insertion of dividers between work stations and an increase in the ceiling's sound absorption improved the acoustic conditions in the office under study. PMID:22507599

  11. Numerical Techniques for Acoustic Modelling and Design of Brass Wind Instruments

    Noreland, Daniel

    2003-01-01

    Acoustic horns are used in musical instruments and loudspeakers in order to provide an impedance match between an acoustic source and the surrounding air. The aim of this study is to develop numerical tools for the analysis and optimisation of such horns, with respect to their input impedance spectra. Important effects such as visco-thermal damping and modal conversion are shown to be localised to different parts of a typical brass instrument. This makes it possible to construct hybrid method...

  12. Design and cost-benefit analysis of a mini thermo-acoustic refrigerator driver

    Livvarcin, Omer.

    2000-01-01

    A miniature thermoacoustic refrigerator is being developed for the purpose of cooling integrated circuits below their failure temperature when used in hot environments. This thesis describes the development of an electrically powered acoustic driver that powers the thermoacoustic refrigerator. The driver utilizes a flexural tri-laminar piezoelectric disk to generate one to two Watts of acoustic power at 4 kHz in 15 bar of He-Kr gas mixture. This thesis also provides a cost analysis of the min...

  13. Optimized Design of Optical Lens of Star Tracker%星跟踪器光学系统的优化设计

    王立秋; 田明; 崔士宝

    2015-01-01

    在星光制导的空间飞行器中,为准确确定空间方位信息,提高导航系统的精度,对星跟踪器光学镜头设计提出很高的要求。针对精度要求,设计了一种新型星跟踪器的光学镜头,系统地阐述了星跟踪器的工作原理,通过光学设计及相差分析,使光学系统的畸变小于0.2%、轴向球差小于0.1,该设计满足用户对高精度天文导航系统的需求。%In the star light guidance of space vehicles, the optical lens design requirements for star tracker are critical to determine accurately the spatial location information and to improve the accuracy of navigation system. A new type of star tracker optical lens system is designed according to the requirements and the operation principle is presented. With the optical design and difference analysis, the optical system distortion is less than 0.2%, the axial spherical aberration is less than 0.1, which can meet the demand for high-precision astronomical navigation system.

  14. A clinical study of Lo-torque designed toric soft contact lens%低旋设计散光软镜临床配戴结果研究

    赵燕杰

    2001-01-01

    目的:评估低旋(Lo-Torque)设计散光软镜的临床效果。方法:103名近视散光自愿者分别配戴A、B镜片各两周。对配戴的临床表现进行客观和主觉评价,采用双盲法。结果:①镜片稳定性:A镜片旋转范围≤5°为82%,B镜片为52%。②镜片在眼中状态:移动度优良者,A镜片为91%,B镜片为95%;中心定位优良者,A镜片为87%,B镜片为77%。③舒适度评价:A镜片优良者为85.5%,B镜片为80.2%。结论:低旋设计特征的散光软镜更符合人眼的生理特征,可以提高视觉质量,增加配戴舒适度。%Objective:To evaluate the impact of the Lo-Torque designed soft toric lenses on the performance of clinical fitting.Methods:103 myopias with astigmatism fitted the A and B lens respectively for 2 weeks, and the evaluation included the subjective and objective examination. The fitting and evaluation is double masked.Results:① Lens stability:A lens rotation≤5° takes 82%,B lens takes 52%.②lens performance:excellence in movement with A lens is 91%,B lens is 95%;excellence in centration with A lens is 87%,B lens is 77%.③confort:excellent with A lens is 85.5%,B lens is 80.2%.Conclusion:Lo-Torique designed soft toric lens is improved better fitting for the toric subjects with better visual acuity and more comfort.

  15. LED Freeform Lens Design for Street Uniform Illumination%用于道路均匀照明的 LED 自由曲面透镜设计

    贺志华; 董前民; 王少雷; 李敏

    2014-01-01

    鉴于LED在道路照明应用中的复杂性和特殊性,以非成像光学为基础,提出了一种新颖的用于道路均匀照明透镜设计方案。运用微分几何原理,建立自由曲面面型的一阶拟线性双曲型偏微分方程,并在matlab中进行数值求解,将所得面型数据导入SolidWorks中建立透镜模型,该透镜将LED朗伯分布转化为道路照明所需的蝙蝠翼分布。通过Tracepro对所建透镜进行光线追迹,结果表明10m处目标面的整体均匀度在85%以上,能量利用率为89.2%。在对扩展光源配光时,该光学系统仍保持较好的照明效果,不仅有效照明区域符合预期,且照度均匀度优于0.80。用DIALux模拟该透镜组成的5×10式模组的路灯系统的照明效果,结果显示路面照度均匀度达0.83,符合国家标准。%Given the complexity and particularity of the LED in the application of street lighting , this paper presents a new lens design method for street uniform lighting based on non-imaging optics .Using the theory of differential geometry to set up the first-order quasi-linear hyperbolic partial differential equations of the freeform lens surface , and solve it by numerical solution in matlab , using the data of the lens profile , the lens model is established in SolidWorks .The designed lens can convert the Lambert distribution of the LED into the bat wing distribution for street lighting .The designed optical system simulated with ray-tracing in TracePro, the results show that the overall uniformity of the 10m distance target plane is above 85%, and the efficiency is 89 .2%.This optical system still maintains good lighting effect when point at extended light source .Not only is the effective illumination area in line with expectations , but also can keep the uniformity above 80%.The street lighting system , which uses the designed lens consisting of 5 ×10-in modular, simulated the lighting effects in DIALux .The

  16. Optimization of Oil-in-Water Emulsion Stability: Experimental Design, Multiple Light Scattering, and Acoustic Attenuation Spectroscopy

    Bendjaballah, Malek; Canselier, Jean-Paul; Oumeddour, Rabah

    2010-01-01

    To find an optimal formulation of oil-in-water (O/W) emulsions (o = 0.05), the effect of emulsifier nature and concentration, agitation speed, emulsifying time, storage temperature and their mutual interactions on the properties and behavior of these dispersions is evaluated by means of an experimental design (Nemrodw software). Long-term emulsion stability is monitored by multiple light scattering (Turbiscan ags) and acoustic attenuation spectroscopy (Ultrasizer). After matching surfactant H...

  17. Development of Generic Methodology for Designing a Structural Health Monitoring Installation Based on the Acoustic Emission Technique

    Gagar, D.; Martinez, M.J.; Foote, P.

    2014-01-01

    The Acoustic Emission (AE) technique can be used to perform damage detection and localisation for structural health monitoring purposes. Implementation in aircraft structures however poses a significant challenge as its performance in terms of damage detection and localisation is not well understood when used with complex structural geometries and variable operational service environments. This paper presents initial developments towards a generic methodology for optimal design of a structura...

  18. Exploration of amphoteric and negative refraction imaging of acoustic sources via active metamaterials

    The present work describes the design of three flat superlens structures for acoustic source imaging and explores an active acoustic metamaterial (AAM) to realise such a design. The first two lenses are constructed via the coordinate transform method (CTM), and their constituent materials are anisotropic. The third lens consists of a material that has both a negative density and a negative bulk modulus. In these lenses, the quality of the images is “clear” and sharp; thus, the diffraction limit of classical lenses is overcome. Finally, a multi-control strategy is developed to achieve the desired parameters and to eliminate coupling effects in the AAM.

  19. Exploration of amphoteric and negative refraction imaging of acoustic sources via active metamaterials

    Wen, Jihong; Shen, Huijie; Yu, Dianlong; Wen, Xisen

    2013-11-01

    The present work describes the design of three flat superlens structures for acoustic source imaging and explores an active acoustic metamaterial (AAM) to realise such a design. The first two lenses are constructed via the coordinate transform method (CTM), and their constituent materials are anisotropic. The third lens consists of a material that has both a negative density and a negative bulk modulus. In these lenses, the quality of the images is “clear” and sharp; thus, the diffraction limit of classical lenses is overcome. Finally, a multi-control strategy is developed to achieve the desired parameters and to eliminate coupling effects in the AAM.

  20. Biomimetic accommodating lens with implementation in MEMS

    Hogan, Alexander L.; Baker, Brian; Fisher, Charles; Naylor, Stephen; Fettig, Doug; Harvey, Ian R.

    2012-03-01

    We describe an accommodating lens patterned after the crystalline lens of the eye. Our biomimetic MEMS design calls to mind the zonules of zinn which pull radially to stretch the crystalline lens of the eye to modify the optical path. We present initial characterization of the prototype macro-scale device constructed through traditional machining techniques and using a PDMS polymer lens. Testing of the macro-scale lens indicated a 22% change in focal length through the range of radial stretching, with degradation of the spherical lens shape but no hysteresis after low-cycle testing. We also demonstrate a MEMS implementation of the lens actuator constructed using the Sandia SUMMiT-V ™ surface micromachining process. The optical path of this system is approximately 300 microns in diameter, providing a platform to potential applications improving mobile camera optics and medical imaging.

  1. A statistical characterization method for damping material properties and its application to structural-acoustic system design

    The performance of surface damping treatments may vary once the surface is exposed to a wide range of temperatures, because the performance of viscoelastic damping material is highly dependent on operational temperature. In addition, experimental data for dynamic responses of viscoelastic material are inherently random, which makes it difficult to design a robust damping layout. In this paper a statistical modeling procedure with a statistical calibration method is suggested for the variability characterization of viscoelastic damping material in constrained-layer damping structures. First, the viscoelastic material property is decomposed into two sources: (I) a random complex modulus due to operational temperature variability, and (II) experimental/model errors in the complex modulus. Next, the variability in the damping material property is obtained using the statistical calibration method by solving an unconstrained optimization problem with a likelihood function metric. Two case studies are considered to show the influence of the material variability on the acoustic performances in the structural-acoustic systems. It is shown that the variability of the damping material is propagated to that of the acoustic performances in the systems. Finally, robust and reliable damping layout designs of the two case studies are obtained through the reliability-based design optimization (RBDO) amidst severe variability in operational temperature and the damping material

  2. Achromatic Fresnel Lens with Improved Efficiency for PV Systems

    Mario González Montes; Juan Carlos Martínez-Antón; Daniel Vázquez Moliní; Antonio Álvarez Fernandez-Balbuena; Bernabeu, E.

    2014-01-01

    This work is aimed to design and evaluate different achromatic Fresnel lens solutions capable of operating as concentrators aimed at photovoltaic cells systems. Throughout this study, the theoretical parametric design of the achromatic lens will be shown together with a series of simulations to verify the performance of each lens topology. The results will be compared with a standard Fresnel lens to ascertain the validity and effectiveness of the obtained design. Finally, a novel kind of hybr...

  3. An Ultra-Low Power and Flexible Acoustic Modem Design to Develop Energy-Efficient Underwater Sensor Networks

    Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

    2012-01-01

    This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network. PMID:22969324

  4. Analysis tools for the design of active structural acoustic control systems

    Oude Nijhuis, Marco Hendrikus Hermanus

    2003-01-01

    Acoustic noise is an important problem in the modern society and provides much of the impetus for the development of noise reduction techniques. Passive methods, such as the use of sound absorbing materials, provide an adequate solution to many noise problems, but for noise reduction at low frequenc

  5. Topological Design for Acoustic-Structure Interaction Problems with a Mixed Finite Element Method

    Yoon, Gil Ho; Jensen, Jakob Søndergaard; Sigmund, Ole

    2006-01-01

    to subdomain interfaces evolving during the optimization process. In this paper, we propose to use a mixed finite element formulation with displacements and pressure as primary variables (u/p formulation) which eliminates the need for explicit boundary representation. In order to describe the...... dimensional acoustic-structure interaction problems are optimized to show the validity of the proposed method....

  6. Analysis of the Acoustic Design of Small Concert Building%小型音乐厅建筑声学设计探析

    吴寄斯

    2014-01-01

    本文针对小型音乐厅的建筑声学设计的重要性,重点围绕混响时间设计、体形设计、吸声材料的设计、噪声控制设计等几个方面,对小型音乐厅建筑声学设计进行了详细分析,以期对提升小型音乐厅的声学设计质量有所借鉴。%This paper, aims at the importance of architectural acoustics design of small concert hal, focusing on reverberat- ion time design, shape design, sound absorption material des- ign, design of noise control and other aspects, analyzed in de- tail the acoustics design of smal concert hals, hoping to pro- vide reference for the quality lifting of acoustic design of smal concerts.

  7. Optimization of Zoom Lens with Discrete State of Liquid Lens Elements by Using Genetic Algorithm

    Cheng-Mu Tsai

    2015-01-01

    Full Text Available This paper is to employ liquid lens elements to design a lens with zoom function by using the genetic algorithm (GA optimization. The liquid lens elements used in the proposal can apply voltage adjustment to generate the electrical field that induces the liquid with electric conductivity to vary the surface curvature between two different kinds of liquids. According to the voltage level, the liquid lens element makes the discrete variation of the curvature and thickness realize the zoom function without moving the lens groups so that the overall length can be reduced. However, it is difficult to design the zoom lens under the discrete variation of the curvature and thickness in the liquid lens elements and the mechanical space that is constantly limited. The GA offers a flexible way for lens optimization. We regarded the spot size as the fitness function to look for the optimum curvatures, thickness, and the corresponding statuses of liquid lens elements for the zoom lens. As a result, the zoom lens with constant space can be realized by running the selection, crossover, and mutation operation in the GA optimization.

  8. Contact lens in keratoconus

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  9. Preliminary design of an advanced programmable digital filter network for large passive acoustic ASW systems. [Parallel processor

    McWilliams, T.; Widdoes, Jr., L. C.; Wood, L.

    1976-09-30

    The design of an extremely high performance programmable digital filter of novel architecture, the LLL Programmable Digital Filter, is described. The digital filter is a high-performance multiprocessor having general purpose applicability and high programmability; it is extremely cost effective either in a uniprocessor or a multiprocessor configuration. The architecture and instruction set of the individual processor was optimized with regard to the multiple processor configuration. The optimal structure of a parallel processing system was determined for addressing the specific Navy application centering on the advanced digital filtering of passive acoustic ASW data of the type obtained from the SOSUS net. 148 figures. (RWR)

  10. 基于 LED 道路照明的偏光透镜设计%Partial Lens Design Based on the LED Road Lighting

    王少雷; 张莉; 李敏; 贺志华; 王乐

    2014-01-01

    基于非均匀网格划分法设计了一种用于LED道路照明的偏光透镜。该透镜能够把LED发出的光线更多地投射在路面上。这种偏光透镜设计减少了道路外的光污染,同时有效提高了路面的光线利用率。在光学软件Lighttools的模拟中,测得整个光学系统照度均匀度为77.6%。并且充分考虑材料的吸收损失和界面的反射损失后,光能利用率高达84.5%。在照明仿真软件Dialux中对该偏光透镜的配光曲线IES模型导入后在模拟道路中进行计算仿真,得到其亮度总均匀度为0.74,并且眩光限制阈值增量控制在9%。所以,该偏光透镜的亮度均匀度、照度均匀度及眩光控制等指标都很好地满足了我国《城市道路照明设计标准》的要求。%In this paper , we designed a partial lens used in LED road lighting , which was based on non-uniform grid partition method .The lens can project more light on the road .The design of the partial lens reduces the light pollution , and improves the utilization of road lighting effectively .And it is not affected by the installation height of lamps and the placement of light pole , it greatly improves the lamp shape and the beautiful design flexibility .The uniformity is 77.6%, which is simulated in the optical software Lighttools . When the light absorption loss of the material and reflection loss of the interface are fully considered , the light energy utilization is as high as 84.5%.And the IES model of light distribution curve of the partial lens is calculated in the lighting simulation software Dialux , the brightness uniformity is 0.74 , and the TI is controlled in 9%.These indicators of intensity of illumination uniformity , brightness uniformity and glare control meet the requirements of The Standards of Street Lighting Design completely.It will have a broad prospect in the application and promotion of road lighting in the future .

  11. Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons

    Thieberger T.; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K.; Hock, J.; Minty, M.; Miller, T.; Montag, C.; Pikin, A.

    2012-04-15

    The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

  12. Design and Fabrication of Acoustic Wave Actuated Microgenerator for Portable Electronic Devices

    Lai, Tenghsien; Tsou, Chingfu

    2008-01-01

    The past few years have seen an increasing focus on energy harvesting issue, including power supply for portable electric devices. Utilize scavenging ambient energy from the environment could eliminate the need for batteries and increase portable device lifetimes indefinitely. In addition, through MEMS technology fabricated micro-generator could easy integrate with these small or portable devices. Several different ambient sources, including solar, vibration and temperature effect, have already exploited [1-3]. Each energy source should be used in suitable environment, therefore to produce maximum efficiency. In this paper, we present an acoustic wave actuated micro-generator for power system by using the energy of acoustic waves, such as the sound from human voices or speakerphone, to actuate a MEMS-type electromagnetic transducer. This provides a longer device lifetime and greater power system convenience. Moreover, it is convenient to integrate MEMS-based microgenerators with small or porta le devices

  13. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    Ladan Espandar

    2011-01-01

    Full Text Available Ladan Espandar1, Shameema Sikder2, Majid Moshirfar31Department of Ophthalmology, Tulane University, New Orleans, LA, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 3John A Moran Eye Center, University of Utah, Salt Lake City, UT, USAAbstract: Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD™ lens is an aspheric, hydrophilic acrylic intraocular lens (IOL. The hydrophilic design of the lens is optimized to address dysphotopsia while maintaining biocompatibility, optical clarity, resistance to damage, and resistance to biocontamination. Aspheric lenses decrease postoperative spherical aberration. The addition of the Softec lens provides clinicians with another option for IOL placement; however, randomized comparative studies of this lens to others already on the market remain to be completed.Keywords: hydrophilic acrylic intraocular lens, Softec HD intraocular lens, aspheric intraocular lens, IOL

  14. Design and Instrumentation of a Measurement and Calibration System for an Acoustic Telemetry System

    Zhiqun Deng; Mark Weiland; Thomas Carlson; M. Brad Eppard

    2010-01-01

    The Juvenile Salmon Acoustic Telemetry System (JSATS) is an active sensing technology developed by the U.S. Army Corps of Engineers, Portland District, for detecting and tracking small fish. It is used primarily for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more “fish-friendly” hydroelectric facilities. The objective of this study was ...

  15. From design to flight testing : overview of rotorcraft acoustic research at onera for industrial applications.

    Delrieux, Y.

    2014-01-01

    The reduction of noise emission has become a key commercial argument for helicopter manufacturers, such as Airbus Helicopters. For years, Airbus helicopters has placed emphasis on the good acoustic behavior of its helicopters, as proven by its communication on the fenestron concept, the acceptance of its aircraft for the Grand Canyon tours and the presentation of its recent Bluecopter™ Technology. Thus, Airbus helicopters has become one of leaders in the manufacture of low noise helicopters.S...

  16. 音乐厅建声设计技术的传承与发展%Heritage and development of architectural acoustics design for concert hall

    章奎生

    2011-01-01

    综述了国内外音乐厅设计与建设的发展历史和过程,介绍了国内外近四十个音乐厅的建设与设计概况及规模体形、主要音质指标和主观音质评价等级等.文中还着重介绍了音乐厅音质设计的三大方面和六点关键技术及我国音乐厅建声设计技术的传承与发展概况.%The history and progress of development of architectural acoustics design for domestic and oversea concert halls is summarized in this paper. The outlines of architecture and acoustics for about forty concert halls in the world are introduced. Those outlines include dimension, somatotype, main acoustical parameters and the rank of subjeaive acoustics evaluation. Then three aspects and six key techniques of acoustics design in concert hall are presented in detail, and the heritage and development of architectural acoustics design for concert hall is introduced in brief.

  17. Color corrected Fresnel lens for solar concentration

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  18. Design and analysis of the trapeziform and flat acoustic cloaks with controllable invisibility performance in a quasi-space

    Jian Zhu

    2015-07-01

    Full Text Available We present the design, implementation and detailed performance analysis for a class of trapeziform and flat acoustic cloaks. An effective large invisible area is obtained compared with the traditional carpet cloak. The cloaks are realized with homogeneous metamaterials which are made of periodic arrangements of subwavelength unit cells composed of steel embedded in air. The microstructures and its effective parameters of the cloaks are determined quickly and precisely in a broadband frequency range by using the effective medium theory and the proposed parameters optimization method. The invisibility capability of the cloaks can be controlled by the variation of the key design parameters and scale factor which are proved to have more influence on the performance in the near field than that in the far field. Different designs are suitable for different application situations. Good cloaking performance demonstrates that such a device can be physically realized with natural materials which will greatly promote the real applications of invisibility cloak.

  19. Design and analysis of the trapeziform and flat acoustic cloaks with controllable invisibility performance in a quasi-space

    Zhu, Jian; Chen, Tianning; Liang, Qingxuan; Wang, Xiaopeng; Xiong, Jie; Jiang, Ping

    2015-07-01

    We present the design, implementation and detailed performance analysis for a class of trapeziform and flat acoustic cloaks. An effective large invisible area is obtained compared with the traditional carpet cloak. The cloaks are realized with homogeneous metamaterials which are made of periodic arrangements of subwavelength unit cells composed of steel embedded in air. The microstructures and its effective parameters of the cloaks are determined quickly and precisely in a broadband frequency range by using the effective medium theory and the proposed parameters optimization method. The invisibility capability of the cloaks can be controlled by the variation of the key design parameters and scale factor which are proved to have more influence on the performance in the near field than that in the far field. Different designs are suitable for different application situations. Good cloaking performance demonstrates that such a device can be physically realized with natural materials which will greatly promote the real applications of invisibility cloak.

  20. 基于液晶自适应透镜的设计与制作%Design and fabrication of adaptive lens based on liquid crystal

    李晖; 张新宇; 张天序; 沈绪榜

    2009-01-01

    详细论述了液晶透镜的设计理论,并在前人已有的工作基础之上改进制作工艺,得到新型单圆孔电极的液晶透镜.与现在已有的单圆孔电极液晶透镜制作工艺相比,改进体现在:使用光刻和盐酸腐蚀的方法.刻蚀ITO基板得到了具有直径为2 mm的圆孔图案的上电极;使用聚酰亚胺取代玻璃作为绝缘层.新型透镜的特性是,工作电压可以低至1.1 V_(rms),焦距范围为20~480 mm,响应时间可达到亚毫秒量级,而在500~1 100 nm范围内透过率稳定在80%以上.通过实验进一步表明:该液晶透镜的点扩展函数(PSF)与理论值接近,且焦距与工作电压成反比例关系.%Design theory of liquid crystal (LC) lenses was described. And its fabrication technology was improved based on existing work of other researchers. A new type of LC lens with single circular aperture electrode was obtained. Compared with the existing fabrication technology of the LC lens with single circular aperture electrode, an improved circular electrode of 2 mm diameter on an ITO substrate with an insulation layer of polyimide (PI) instead of glass was etched through photolithography and hydrochloric acid etching. The new type of lenses fabricated by the improved technology has advantages of low work voltage of 1.1 V_(rms), wide focal length range from 20 nun to 480 nun, short response time of sub-millisecond order, and stable transmittance of higher than 80 percents within the wavelength range from 500 nm to 1 100 nm. Further experiment shows that the point spread function (PSF) of the LC lens approaches its theoretical limit, and its focal length is inverse proportion to its work voltage.

  1. Design and simulation study of high frequency response for surface acoustic wave device by using CST software

    Zakaria, M. R.; Hashim, U.; Amin, Mohd Hasrul I. M.; Ayub, R. Mat; Hashim, M. N.; Adam, T.

    2015-05-01

    This paper focuses on the enhancement and improvement of the Surface Acoustic Wave (SAW) device performance. Due to increased demand in the international market for biosensor product, the product must be emphasized in terms of quality. However, within the technological advances, demand for device with low cost, high efficiency and friendly-user preferred. Surface Acoustic Wave (SAW) device with the combination of pair electrode know as Interdigital Transducer (IDT) was fabricated on a piezoelectric substrate. The design of Interdigital Transducer (IDT) parameter is changes in several sizes and values for which it is able to provide greater efficiency in sensing sensitivity by using process simulation with CST STUDIO Suite software. In addition, Interdigital Transducer (IDT) parameters also changed to be created the products with a smaller size and easy to handle where it also reduces the cost of this product. Parameter values of an Interdigital Transducer (IDT) will be changed in the design is the total number of fingers pair, finger length, finger width and spacing, aperture and also the thickness of the Interdigital Transducer (IDT). From the result, the performance of the sensor is improved significantly after modification is done.

  2. Wavefront Modulation and Subwavelength Diffractive Acoustics with an Acoustic Metasurface

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-01-01

    Metasurfaces are a family of novel wavefront shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality as their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a desig...

  3. 汉源新县城体育中-会议中心声学设计%The Acoustics Design of Hanyuan Gymnasium Conference Centre

    李运江; 周小庚; 范波

    2011-01-01

    By using of archilectural acoustics simulation software, some acoustic parameters of Hanyuan Gymnasium have been calculated.Some building construction has been optimzed acoustic decoration design has been corried out for the specific circumstance the acoustic parameters hove been adjusted to meet the requirements of relevant national codes.A opproach on the complete combination of technology and arts has been done.%利用建筑声学仿真软件,对汉源新县城体育中心-会议中心的部分声学参教进行了计算,时一些建筑构造进行了优化,并针对其具体特点进行了声学装修设计,使其声学参数达到国家规范取值范围,力争实现技术和艺术的完整结合.

  4. Classroom acoustics design guidelines based on the optimization of speaker conditions

    Pelegrin Garcia, David; Brunskog, Jonas

    2012-01-01

    suggested in order to optimize the vocal comfort and the vocal load experienced by speakers. Theoretical prediction models of room-averaged speaker-oriented parameters like voice support or reverberation time derived from an oral-binaural impulse response are combined with empirical models of actual voice...... and noise level measurements in classrooms. Requirements of optimum vocal comfort, average A-weighted speech levels across the audience higher than 50 dB, and a physical volume higher than 6 m3/student are combined to extract optimum acoustic conditions, which depend on the number of students. These...

  5. From Architectural Acoustics to Acoustical Architecture Using Computer Simulation

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2005-01-01

    Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in architectural acoustics and the emergence of room acoustic simulation programmes with considerable potential, it is now possible to subjectively analyse and evaluate acoustic...... properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to investigate the field of application that an acoustic simulation programme can have during an architectural...... the first phases in the architectural process and set out a reverse strategy for simulation programmes to do so - from developing acoustics from given spaces to developing spaces from given acoustics...

  6. All-dielectric subwavelength metasurface focusing lens.

    West, Paul R; Stewart, James L; Kildishev, Alexander V; Shalaev, Vladimir M; Shkunov, Vladimir V; Strohkendl, Friedrich; Zakharenkov, Yuri A; Dodds, Robert K; Byren, Robert

    2014-10-20

    We have proposed, designed, manufactured and tested low loss dielectric micro-lenses for infrared (IR) radiation based on a dielectric metamaterial layer. This metamaterial layer was created by patterning a dielectric surface and etching to sub-micron depths. For a proof-of-concept lens demonstration, we have chosen a fine patterned array of nano-pillars with variable diameters. Gradient index (GRIN) properties were achieved by engineering the nano-pattern characteristics across the lens, so that the effective optical density of the dielectric metamaterial layer peaks around the lens center, and gradually drops at the lens periphery. A set of lens designs with reduced reflection and tailorable phase gradients have been developed and tested, demonstrating focal distances of a few hundred microns, beam area contraction ratio up to three, and insertion losses as low as 11%. PMID:25401653

  7. Lens system for SIMS analysis

    A powerful version of the charge-density method is applied to the study of a combined objective and emission lens, suitable for highly localized analysis of a flat sample surface. This lens can extract secondary ions of equal or opposite polarity to that of the primary particles. A computer simulation of the ion trajectories for both modes is made. The behaviour for different values of the geometric parameters and polarizations is analyzed and useful data for design such as primary beam demagnification and secondary image position are given. (author) 4 refs

  8. Contact Lens Solution Toxicity

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  9. Finite Difference Time Marching in the Frequency Domain: A Parabolic Formulation for Aircraft Acoustic Nacelle Design

    Baumeister, Kenneth J.; Kreider, Kevin L.

    1996-01-01

    An explicit finite difference iteration scheme is developed to study harmonic sound propagation in aircraft engine nacelles. To reduce storage requirements for large 3D problems, the time dependent potential form of the acoustic wave equation is used. To insure that the finite difference scheme is both explicit and stable, time is introduced into the Fourier transformed (steady-state) acoustic potential field as a parameter. Under a suitable transformation, the time dependent governing equation in frequency space is simplified to yield a parabolic partial differential equation, which is then marched through time to attain the steady-state solution. The input to the system is the amplitude of an incident harmonic sound source entering a quiescent duct at the input boundary, with standard impedance boundary conditions on the duct walls and duct exit. The introduction of the time parameter eliminates the large matrix storage requirements normally associated with frequency domain solutions, and time marching attains the steady-state quickly enough to make the method favorable when compared to frequency domain methods. For validation, this transient-frequency domain method is applied to sound propagation in a 2D hard wall duct with plug flow.

  10. The Baryon Acoustic Oscillation Broadband and Broad-beam Array: Design Overview and Sensitivity Forecasts

    Pober, Jonathan C; DeBoer, David R; McDonald, Patrick; McQuinn, Matthew; Aguirre, James E; Ali, Zaki; Bradley, Richard F; Chang, Tzu-Ching; Morales, Miguel F

    2012-01-01

    This work describes a new instrument optimized for a detection of the neutral hydrogen 21cm power spectrum between redshifts of 0.5-1.5: the Baryon Acoustic Oscillation Broadband and Broad-beam (BAOBAB) Array. BAOBAB will build on the efforts of a first generation of 21cm experiments which are targeting a detection of the signal from the Epoch of Reionization at z ~ 10. At z ~ 1, the emission from neutral hydrogen in self-shielded overdense halos also presents an accessible signal, since the dominant, synchrotron foreground emission is considerably fainter than at redshift 10. The principle science driver for these observations are Baryon Acoustic Oscillations in the matter power spectrum which have the potential to act as a standard ruler and constrain the nature of dark energy. BAOBAB will fully correlate dual-polarization antenna tiles over the 600-900MHz band with a frequency resolution of 300 kHz and a system temperature of 50K. The number of antennas will grow in staged deployments, and reconfigurations...

  11. Nanoparticle-Laden Contact Lens for Controlled Ocular Delivery of Prednisolone: Formulation Optimization Using Statistical Experimental Design

    Amr ElShaer

    2016-04-01

    Full Text Available Human eye is one of the most accessible organs in the body, nonetheless, its physiology and associated precorneal factors such as nasolacrimal drainage, blinking, tear film, tear turnover, and induced lacrimation has significantly decreased the residence time of any foreign substances including pharmaceutical dosage forms. Soft contact lenses are promising delivery devices that can sustain the drug release and prolong residence time by acting as a geometric barrier to drug diffusion to tear fluid. This study investigates experimental parameters such as composition of polymer mixtures, stabilizer and the amount of active pharmaceutical ingredient on the preparation of a polymeric drug delivery system for the topical ocular administration of Prednisolone. To achieve this goal, prednisolone-loaded poly (lactic-co-glycolic acid (PLGA nanoparticles were prepared by single emulsion solvent evaporation method. Prednisolone was quantified using a validated high performance liquid chromatography (HPLC method. Nanoparticle size was mostly affected by the amount of co-polymer (PLGA used whereas drug load was mostly affected by amount of prednisolone (API used. Longer homogenization time along with higher amount of API yielded the smallest size nanoparticles. The nanoparticles prepared had an average particle size of 347.1 ± 11.9 nm with a polydispersity index of 0.081. The nanoparticles were then incorporated in the contact lens mixture before preparing them. Clear and transparent contact lenses were successfully prepared. When the nanoparticle (NP-loaded contact lenses were compared with control contact lenses (unloaded NP contact lenses, a decrease in hydration by 2% (31.2% ± 1.25% hydration for the 0.2 g loaded NP contact lenses and light transmission by 8% (unloaded NP contact lenses 94.5% NP 0.2 g incorporated contact lenses 86.23%. The wettability of the contact lenses remained within the desired value (<90 °C even upon incorporation of the NP. NP

  12. Nanoparticle-Laden Contact Lens for Controlled Ocular Delivery of Prednisolone: Formulation Optimization Using Statistical Experimental Design.

    ElShaer, Amr; Mustafa, Shelan; Kasar, Mohamad; Thapa, Sapana; Ghatora, Baljit; Alany, Raid G

    2016-01-01

    Human eye is one of the most accessible organs in the body, nonetheless, its physiology and associated precorneal factors such as nasolacrimal drainage, blinking, tear film, tear turnover, and induced lacrimation has significantly decreased the residence time of any foreign substances including pharmaceutical dosage forms. Soft contact lenses are promising delivery devices that can sustain the drug release and prolong residence time by acting as a geometric barrier to drug diffusion to tear fluid. This study investigates experimental parameters such as composition of polymer mixtures, stabilizer and the amount of active pharmaceutical ingredient on the preparation of a polymeric drug delivery system for the topical ocular administration of Prednisolone. To achieve this goal, prednisolone-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by single emulsion solvent evaporation method. Prednisolone was quantified using a validated high performance liquid chromatography (HPLC) method. Nanoparticle size was mostly affected by the amount of co-polymer (PLGA) used whereas drug load was mostly affected by amount of prednisolone (API) used. Longer homogenization time along with higher amount of API yielded the smallest size nanoparticles. The nanoparticles prepared had an average particle size of 347.1 ± 11.9 nm with a polydispersity index of 0.081. The nanoparticles were then incorporated in the contact lens mixture before preparing them. Clear and transparent contact lenses were successfully prepared. When the nanoparticle (NP)-loaded contact lenses were compared with control contact lenses (unloaded NP contact lenses), a decrease in hydration by 2% (31.2% ± 1.25% hydration for the 0.2 g loaded NP contact lenses) and light transmission by 8% (unloaded NP contact lenses 94.5% NP 0.2 g incorporated contact lenses 86.23%). The wettability of the contact lenses remained within the desired value (<90 °C) even upon incorporation of the NP. NP alone and

  13. Nanoparticle-Laden Contact Lens for Controlled Ocular Delivery of Prednisolone: Formulation Optimization Using Statistical Experimental Design

    ElShaer, Amr; Mustafa, Shelan; Kasar, Mohamad; Thapa, Sapana; Ghatora, Baljit; Alany, Raid G.

    2016-01-01

    Human eye is one of the most accessible organs in the body, nonetheless, its physiology and associated precorneal factors such as nasolacrimal drainage, blinking, tear film, tear turnover, and induced lacrimation has significantly decreased the residence time of any foreign substances including pharmaceutical dosage forms. Soft contact lenses are promising delivery devices that can sustain the drug release and prolong residence time by acting as a geometric barrier to drug diffusion to tear fluid. This study investigates experimental parameters such as composition of polymer mixtures, stabilizer and the amount of active pharmaceutical ingredient on the preparation of a polymeric drug delivery system for the topical ocular administration of Prednisolone. To achieve this goal, prednisolone-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by single emulsion solvent evaporation method. Prednisolone was quantified using a validated high performance liquid chromatography (HPLC) method. Nanoparticle size was mostly affected by the amount of co-polymer (PLGA) used whereas drug load was mostly affected by amount of prednisolone (API) used. Longer homogenization time along with higher amount of API yielded the smallest size nanoparticles. The nanoparticles prepared had an average particle size of 347.1 ± 11.9 nm with a polydispersity index of 0.081. The nanoparticles were then incorporated in the contact lens mixture before preparing them. Clear and transparent contact lenses were successfully prepared. When the nanoparticle (NP)-loaded contact lenses were compared with control contact lenses (unloaded NP contact lenses), a decrease in hydration by 2% (31.2% ± 1.25% hydration for the 0.2 g loaded NP contact lenses) and light transmission by 8% (unloaded NP contact lenses 94.5% NP 0.2 g incorporated contact lenses 86.23%). The wettability of the contact lenses remained within the desired value (<90 °C) even upon incorporation of the NP. NP alone and

  14. Achieving selective interrogation and sub-wavelength resolution in thin plates with embedded metamaterial acoustic lenses

    In this study, we present an approach to ultrasonic beam-forming and high resolution identification of acoustic sources having critical implications for applications such as structural health monitoring. The proposed concept is based on the design of dynamically tailored structural elements via embedded acoustic metamaterial lenses. This approach provides a completely new alternative to conventional phased-array technology enabling the formation of steerable and collimated (or focused) ultrasonic beams by exploiting a single transducer. Numerical results show that the ultrasonic beam can be steered by simply tuning the frequency of the excitation. Also, the embedded lens can be designed to achieve sub-wavelength resolution to clustered acoustic sources, which is a typical scenario encountered in incipient structural damage

  15. Use of co-combustion bottom ash to design an acoustic absorbing material for highway noise barriers

    Arenas, Celia; Leiva, Carlos; Vilches, Luis F. [University of Seville, School of Industrial Engineering, Department of Chemical and Environmental Engineering, Camino de los Descubrimientos s/n, E-41092 Seville (Spain); Cifuentes, Héctor, E-mail: bulte@us.es [University of Seville, School of Industrial Engineering, Continuum Mechanics and Structural Analysis Department, Camino de los Descubrimientos s/n, E-41092 Seville (Spain)

    2013-11-15

    Highlights: • The particle size of bottom ash influenced the acoustic behavior of the barrier. • The best sound absorption coefficients were measured for larger particle sizes. • The maximum noise absorption is displaced to lower frequencies for higher thickness. • A noise barrier was designed with better properties than commercial products. • Recycling products from bottom ash no present leaching and radioactivity problems. - Abstract: The present study aims to determine and evaluate the applicability of a new product consisting of coal bottom ash mixed with Portland cement in the application of highway noise barriers. In order to effectively recycle the bottom ash, the influence of the grain particle size of bottom ash, the thickness of the panel and the combination of different layers with various particle sizes have been studied, as well as some environmental properties including leachability (EN-12457-4, NEN-7345) and radioactivity tests. Based on the obtained results, the acoustic properties of the final composite material were similar or even better than those found in porous concrete used for the same application. According to this study, the material produced presented no environmental risk.

  16. Design and implementation of an omni-directional underwater acoustic micro-modem based on a low-power micro-controller unit.

    Won, Tae-Hee; Park, Sung-Joon

    2012-01-01

    For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense of large size and high power consumption. Recently, as the need for underwater wireless sensor networks (UWSNs) has increased, the research and development of compact and low-power consuming communication devices has become the focus. From the consideration that the requisites of acoustic modems for UWSNs are low power consumption, omni-directional beam pattern, low cost and so on, in this paper, we design and implement an omni-directional underwater acoustic micro-modem satisfying these requirements. In order to execute fast digital domain signal processing and support flexible interfaces with other peripherals, an ARM Cortex-M3 is embedded in the micro-modem. Also, for the realization of small and omni-directional properties, a spherical transducer having a resonant frequency of 70 kHz and a diameter of 34 mm is utilized for the implementation. Physical layer frame format and symbol structure for efficient packet-based underwater communication systems are also investigated. The developed acoustic micro-modem is verified analytically and experimentally in indoor and outdoor environments in terms of functionality and performance. Since the modem satisfies the requirements for use in UWSNs, it could be deployed in a wide range of applications requiring underwater acoustic communication. PMID:22438765

  17. Design and Implementation of an Omni-Directional Underwater Acoustic Micro-Modem Based on a Low-Power Micro-Controller Unit

    Sung-Joon Park

    2012-02-01

    Full Text Available For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense of large size and high power consumption. Recently, as the need for underwater wireless sensor networks (UWSNs has increased, the research and development of compact and low-power consuming communication devices has become the focus. From the consideration that the requisites of acoustic modems for UWSNs are low power consumption, omni-directional beam pattern, low cost and so on, in this paper, we design and implement an omni-directional underwater acoustic micro-modem satisfying these requirements. In order to execute fast digital domain signal processing and support flexible interfaces with other peripherals, an ARM Cortex-M3 is embedded in the micro-modem. Also, for the realization of small and omni-directional properties, a spherical transducer having a resonant frequency of 70 kHz and a diameter of 34 mm is utilized for the implementation. Physical layer frame format and symbol structure for efficient packet-based underwater communication systems are also investigated. The developed acoustic micro-modem is verified analytically and experimentally in indoor and outdoor environments in terms of functionality and performance. Since the modem satisfies the requirements for use in UWSNs, it could be deployed in a wide range of applications requiring underwater acoustic communication.

  18. Development of a Liner Design Methodology and Relevant Results of Acoustic Suppression in the Farfield for Mixer-Ejector Nozzles

    Salikuddin, M.

    2006-01-01

    We have developed a process to predict noise field interior to the ejector and in the farfield for any liner design for a mixer-ejector of arbitrary scale factor. However, a number of assumptions, not verified for the current application, utilized in this process, introduce uncertainties in the final result, especially, on a quantitative basis. The normal impedance model for bulk with perforated facesheet is based on homogeneous foam materials of low resistivity. The impact of flow conditions for HSCT application as well as the impact of perforated facesheet on predicted impedance is not properly accounted. Based on the measured normal impedance for deeper bulk samples (i.e., 2.0 in.) the predicted reactance is much higher compared to the data at frequencies above 2 kHz for T-foam and 200 ppi SiC. The resistance is under predicted at lower frequencies (below 4 kHz) for these samples. Thus, the use of such predicted data in acoustic suppression is likely to introduce inaccuracies. It should be noted that the impedance prediction methods developed recently under liner technology program are not utilized in the studies described in this report due to the program closeout. Acoustic suppression prediction is based on the uniform flow and temperature conditions in a two-sided treated constant area rectangular duct. In addition, assumptions of equal energy per mode noise field and interaction of all frequencies with the treated surface for the entire ejector length may not be accurate. While, the use of acoustic transfer factor minimizes the inaccuracies associated with the prediction for a known test case, the assumption of the same factor for other liner designs and with different linear scale factor ejectors seems to be very optimistic. As illustrated in appendix D that the predicted noise suppression for LSM-1 is lower compared to the measured data is an indication of the above argument. However, the process seems to be more reliable when used for the same scale

  19. Fresnel lens solar beam convergence properties

    Huang, Minshuang; Tian, Feng

    2014-11-01

    Use the law of refraction of light for theoretical analysis of sunlight incident Fresnel lens, summary of the relationship between Fresnel lens solar light beam convergence characteristics and beam incident angle,beam incident position.Through the analysis of the calculation and experimental, to obtain a variety of incident angle lens center and best gathering focal spot the size of the data.Discuss the incident angle, incident location,the relationship between convergence center and focal spot size.For the sun acquisition system of the light from the sun and optical fiber coupling design do sufficient theory design basis.

  20. Acoustic telemetry and network analysis reveal the space use of multiple reef predators and enhance marine protected area design.

    Lea, James S E; Humphries, Nicolas E; von Brandis, Rainer G; Clarke, Christopher R; Sims, David W

    2016-07-13

    Marine protected areas (MPAs) are commonly employed to protect ecosystems from threats like overfishing. Ideally, MPA design should incorporate movement data from multiple target species to ensure sufficient habitat is protected. We used long-term acoustic telemetry and network analysis to determine the fine-scale space use of five shark and one turtle species at a remote atoll in the Seychelles, Indian Ocean, and evaluate the efficacy of a proposed MPA. Results revealed strong, species-specific habitat use in both sharks and turtles, with corresponding variation in MPA use. Defining the MPA's boundary from the edge of the reef flat at low tide instead of the beach at high tide (the current best in Seychelles) significantly increased the MPA's coverage of predator movements by an average of 34%. Informed by these results, the larger MPA was adopted by the Seychelles government, demonstrating how telemetry data can improve shark spatial conservation by affecting policy directly. PMID:27412274

  1. LensClean revisited

    Wucknitz, O

    2004-01-01

    We discuss the LensClean algorithm which for a given gravitational lens model fits a source brightness distribution to interferometric radio data in a similar way as standard Clean does in the unlensed case. The lens model parameters can then be varied in order to minimize the residuals and determine the best model for the lens mass distribution. Our variant of this method is improved in order to be useful and stable even for high dynamic range systems with nearly degenerated lens model parameters. Our test case B0218+357 is dominated by two bright images but the information needed to constrain the unknown parameters is provided only by the relatively smooth and weak Einstein ring. The new variant of LensClean is able to fit lens models even in this difficult case. In order to allow the use of general mass models with LensClean, we develop the new method LenTil which inverts the lens equation much more reliably than any other method. This high reliability is essential for the use as part of LensClean. Finally...

  2. AST Launch Vehicle Acoustics

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  3. Real-time Parallel Processing System Design and Implementation for Underwater Acoustic Communication Based on Multiple Processors

    YAN Zhen-hua; HUANG Jian-guo; ZHANG Qun-fei; HE Cheng-bing

    2007-01-01

    ADSP-TS101 is a high performance DSP with good properties of parallel processing and high speed. According to the real-time processing requirements of underwater acoustic communication algorithms, a real-time parallel processing system with multi-channel synchronous sample, which is composed of multiple ADSP-TS101s, is designed and carried out.For the hardware design, field programmable gate array (FPGA) logical control is adopted for the design of multi-channel synchronous sample module and cluster/data flow associated pin connection mode is adopted for multiprocessing parallel processing configuration respectively. And the software is optimized by two kinds of communication ways: broadcast writing way through shared bus and point-to-point way through link ports. Through the whole system installation, connective debugging, and experiments in a lake, the results show that the real-time parallel processing system has good stability and real-time processing capability and meets the technical design requirements of real-time processing.

  4. Cochlear bionic acoustic metamaterials

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  5. Patient acceptability of the Tecnis® multifocal intraocular lens

    Sood, Priyanka; Woodward, Maria A.

    2011-01-01

    Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients’ desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL) designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus....

  6. Acoustic dispersive prism

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  7. The design and calibration of particular geometry piezoelectric acoustic emission transducer for leak detection and localization

    Yalcinkaya, Hazim; Ozevin, Didem

    2013-09-01

    Pipeline leak detection using an acoustic emission (AE) method requires highly sensitive transducers responding to less attenuative and dispersive wave motion in order to place the discrete transducer spacing in an acceptable approach. In this paper, a new piezoelectric transducer geometry made of PZT-5A is introduced to increase the transducer sensitivity to the tangential direction. The finite element analysis of the transducer geometry is modeled in the frequency domain to identify the resonant frequency, targeting 60 kHz, and the loss factor. The numerical results are compared with the electromechanical characterization tests. The transducer response to wave motion generated in different directions is studied using a multiphysics model that couples mechanical and electrical responses of structural and piezoelectric properties. The directional dependence and the sensitivity of the transducer response are identified using the laser-induced load function. The transducer response is compared with a conventional thickness mode AE transducer under simulations and leak localization in a laboratory scale steel pipe.

  8. The Optical Design of a System using a Fresnel Lens that Gathers Light for a Solar Concentrator and that Feeds into Solar Alignment Optics

    Wilkerson, Gary W.; Huegele, Vinson

    1998-01-01

    The Marshall Space Flight Center (MSFC) has been developing a space deployable, lightweight membrane concentrator to focus solar energy into a solar furnace while remaining aligned to the sun. For an inner surface, this furnace has a cylindrical heat exchanger cavity coaligned to the optical axis; the furnace warms gas to propel the spacecraft. The membrane concentrator is a 1727 mm (68.00 in.) diameter, F/1.7 Fresnel lens. This large membrane is made from polyimide and is 0.076 mm (0.0030 in.) thick; it has the Fresnel grooves cast into it. The solar concentrator system has a super fast paraboloid reflector near the lens focus and immediately adjacent to the cylindrical exchanger cavity. The paraboloid collects the wide bandwidth and some of the solar energy scattered by the Fresnel lens. Finally, the paraboloid feeds the light into the cylinder. The Fresnel lens also possesses a narrow annular zone that focuses a reference beam toward four detectors that keep the optical system aligned to the sun; thus, occurs a refracting lens that focuses two places! The result can be summarized as a composite Fresnel lens for solar concentration and alignment.

  9. The Deep Lens Survey

    Wittman, D; Dell'Antonio, I P; Becker, A C; Margoniner, V E; Cohen, J; Norman, D; Loomba, D; Squires, G; Wilson, G; Stubbs, C; Hennawi, J F; Spergel, D N; Boeshaar, P C; Clocchiatti, A; Hamuy, M; Bernstein, G; González, A; Guhathakurta, R; Hu, W; Seljak, U; Zaritsky, D

    2002-01-01

    The Deep Lens Survey (DLS) is a deep BVRz' imaging survey of seven 2x2 degree fields, with all data to be made public. The primary scientific driver is weak gravitational lensing, but the survey is also designed to enable a wide array of other astrophysical investigations. A unique feature of this survey is the search for transient phenomena. We subtract multiple exposures of a field, detect differences, classify, and release transients on the Web within about an hour of observation. Here we summarize the scientific goals of the DLS, field and filter selection, observing techniques and current status, data reduction, data products and release, and transient detections. Finally, we discuss some lessons which might apply to future large surveys such as LSST.

  10. Eccentricity effects on acoustic radiation from a spherical source suspended within a thermoviscous fluid sphere.

    Hasheminejad, Seyyed M; Azarpeyvand, Mahdi

    2003-11-01

    Acoustic radiation from a spherical source undergoing angularly periodic axisymmetric harmonic surface vibrations while eccentrically suspended within a thermoviscous fluid sphere, which is immersed in a viscous thermally conducting unbounded fluid medium, is analyzed in an exact fashion. The formulation uses the appropriate wave-harmonic field expansions along with the translational addition theorem for spherical wave functions and the relevant boundary conditions to develop a closed-form solution in form of infinite series. The analytical results are illustrated with a numerical example in which the vibrating source is eccentrically positioned within a chemical fluid sphere submerged in water. The modal acoustic radiation impedance load on the source and the radiated far-field pressure are evaluated and discussed for representative values of the parameters characterizing the system. The proposed model can lead to a better understanding of dynamic response of an underwater acoustic lens. It is equally applicable in miniature transducer analysis and design with applications in medical ultrasonics. PMID:14682628

  11. Conjugate metamaterials and the perfect lens

    Xu, Yadong; Xu, Lin; Chen, Huanyang

    2015-01-01

    In this letter, we show how transformation optics makes it possible to design what we call conjugate metamaterials. We show that these materials can also serve as substrates for making a subwavelength-resolution lens. The so-called "perfect lens", which is a lens that could focus all components of light (including propagating and evanescent waves), can be regarded as a limiting case, in which the respective conjugate metamaterials approach the characteristics of left-handed metamaterials, which have a negative refractive index.

  12. USE OF SCALE MODELING FOR ARCHITECTURAL ACOUSTIC MEASUREMENTS

    ERÖZ, Ferhat

    2013-01-01

    In recent years, acoustic science and hearing has become important. Acoustic design used in tests of acoustic devices is crucial. Sound propagation is a complex subject, especially inside enclosed spaces. From the 19th century on, the acoustic measurements and tests were carried out using modeling techniques that are based on room acoustic measurement parameters.In this study, the effects of architectural acoustic design of modeling techniques and acoustic parameters were studied. In this con...

  13. Len Yi Part 2

    Bsod nams rgyal mtshan

    2011-01-01

    INTRODUCTION: Sonan Jetsun (Bsod nams rgyal mtshan) filmed this material 12-22 January 2008 in Len yi (Lianyi) Village, Sgong po (Gongbo) Township, Sde rong (Derong) County, Dkar mdzes (Ganzi) Tibetan Autonomous Prefecture, Si khron (Sichuan) Province, PR China. The film features the Tibetan New Year, Bkra shis Temple, and ordinary people's lives in Len yi Village. Sonan Jetsun also edited the material and plans to give it to Len yi villagers on DVD/ VCD. LOCATION: Lianyi Village is 200 k...

  14. REFRACTIVE NEUTRON LENS

    Petrov, P. V.; Kolchevsky, N.N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  15. 星光半物理实验平台遮光罩设计新方法%Lens-Hood Design of Starlight Semi-Physical Experimental Platform

    刘文东; 杨博

    2012-01-01

    In order to restore the contrast of celestial simulator-generated starlight with the surrounding dark background, improve the recognition rate of the star map and navigation solution accuracy, a new design of the lens hood for celestial navigation simulation system to decrease environmental stray light is discussed detailedly. Design formula is derived in accordance with its principles, and a new method to calculate the position and size of the vane inside the hood with computer program is proposed. Using the baffle model established in TracePro, 18 different deviation angles between 1° ~ 85° of parallel light source are simulated. The stray light suppression curves for different deviation angles are obtained. Results show that above 25°, suppression ratio of the luminous flux decreases to the order of magnitude of 10-3. A physical test is carried out on semi-physical simulation platform. The actual results show that this design of the lens hood can decrease the environmental stray light and effectively restore the contrast of starlight simulator.%详细论述了星光半物理实验平台用遮光罩抑制实验环境杂光的一种新的设计思想,用以最大程度地还原星光模拟器产生的模拟星光与周围暗背景的对比度,从而大大提高了实验检测精度.根据实验系统原理推导出一整套设计公式,并提出利用程序递推计算遮光罩内部挡光环位置和尺寸的新方法.在TracePro杂光分析软件中建立遮光罩实验模型,对遮光罩径向成1°~85°之间的18个偏角的平行光源进行杂光抑制情况模拟,通过计算得到不同偏角遮光罩杂光抑制能力曲线.仿真结果表明,杂光偏角为25°以上时,光通量抑制比下降到10-3量级.加工出实物在半物理仿真平台上进行检验,实际拍摄结果显示,以该方法设计的遮光罩能够有效抑制环境中的杂散光,还原星光模拟器的对比度,使CCD相机能够准确观测到6等以上的星,保证了实验系统的可靠性.

  16. Forward acoustic performance of a model turbofan designed for a high specific flow (QF-14)

    Lucas, J. G.; Woodward, R. P.; Michels, C. J.

    1982-01-01

    Forward noise and overall aerodynamic performance are presented for a high-tip-speed fan having an exceptionally high average axial Mach number at the rotor inlet. This high Mach number is intended to attenuate forward noise at both the design-speed takeoff point, and at the unconventional low-pressure-ratio, design-speed approach point. As speed was increased near design, all forward noise components were reduced, and rear noise in the discharge duct was increased, indicating that the high Mach number flow at the rotor face is attenuating forward noise at takeoff. The fan at takeoff is some 5.5 to 11 dB quieter than several reference fans. Data at the point closest to approach indicated tentatively that the design-speed approach mode was 3 dB quieter than the conventional mode.

  17. A Spectrometer Based on Diffractive Lens

    WANG Daoyi; YAN Yingbai; JIN Guofan; WU Minxian

    2001-01-01

    A novel spectrometer is designed based on diffractive lens. It is essentially a flat field spectrometer. All the focal points are along the optical axis. Besides, all the asymmetrical aberrations vanish in our mounting. Thus low aberration can be obtained. In this article a diffractive lens is modeled as a special grating and analyzed by using a grating-based method. And a stigmatic point is introduced to reduce the aberrations.

  18. Parametric modeling of zoom lens barrels

    Pierce, Charles W.

    2001-12-01

    Today's customer requires zoom lens designs that are compact, inexpensive, and at six-sigma quality levels. While incorporating these customer requirements, a design team must often work within compressed design cycles and minimal product development budgets. These customer and project constraints, coupled with the inherent complexity of a zoom lens module, force the design team to try new and innovative techniques to deliver their products. This paper presents the methods used to develop lens barrels for several zoom lens module projects at Eastman Kodak Company. The lens barrel, a critical interface between the mechanical and optical systems, presented a technical barrier from both an engineering analysis and manufacturing perspective. The method used to overcome these barriers consisted of identifying several key functional parameters, creating a parameter-driven 3-D solid model in a commercially available CAD system, and then using the model to make iterative, data-driven design decisions while leveraging the model to create engineering drawings and the necessary prototypes and production tooling. As a result, the designs were able to meet their size, cost, and design cycle time requirements while realizing a better than anticipated first pass yield and quality level.

  19. Acoustical design of younger gymnasium ningbo sports center%宁波市体育中心雅戈尔体育馆音质改建设计

    章奎生; 杨志刚

    2001-01-01

    宁波体育馆建成5年来音质一直不佳,文章指出了音质不良的原因,介绍了音质改建指标、设计计算方法、空间吸声体和吸声墙面用料、结构的配置设计等技术,改建后经现场测试与主观评价,取得了满意的音质效果,达到了设计要求。%Younger Gymnasium has acoustical problem since it was constructed five years ago.In this paper,the cause of acoustical problem,acoustical parameters and the method of design and calculation have been analysed.The paper also gives the arrangement and structure of absorbent.The results of field testing and subjective evaluation showed that the acoustical design reach a desired effect.

  20. Re-evaluating Science and Technology trough the lens of Arts and Graphic Design. A case study in La Spezia.

    Locritani, Marina; Stroobant, Mascha; Talamoni, Roberta; Merlino, Silvia; Guccinelli, Giacomo; Benvenuti, Lucrezia; Zatta, Consuelo; Stricker, Federica; Zappa, Franco; Sgherri, Matteo

    2016-04-01

    The Human society is getting more and more involved with scientific and environmental issues both in terms of consciousness of good practices or participation in legislative decision-making processes. A common effort to preserve our planet is asked every day, for example through recycling practices, reduction of pollutant emission, use of alternative energies and awareness of risks natural and human-induced hazards. In addition, public opinion is often involved for issues of scientific interest (e.g. genetically modified organisms GMO). Unfortunately, the Eurobarometer (Eurobarometer Special 419 Report, Public perceptions of Science, Research and Innovation, 2014) indicates, especially for the Italian population, a low interest in science and therefore a lack of confidence in the potential of the research. It is hence important for people to be informed of the progress made by science and the importance of the researchers' role. Education, awareness and dissemination of scientific results and issues must be made through simple and appealing channels that must reach all levels of society and age groups: from children to older people. A common and comprehensible language for everyone can be found in Graphic Arts. For this reasons, the working group for science dissemination of La Spezia has increased, in recent years, close relationship with some artists (especially graphic designers). The collaboration between two different worlds (art and science) has allowed us to see an unusual approach and to translate concepts developed in images which everyone can understand also under an emotional point of view. Different techniques and tools based on the target to be reached have been employed. 1. Conferences. Gender differences issues in science professions and more generally in society has been addressed through interactive conferences and round tables during the European Researchers' Night 2015 and other occasions for general public. Arguments and questions were described

  1. Acoustic Fresnel lenses with extraordinary transmission

    Molerón, Miguel; Serra-Garcia, Marc; Daraio, Chiara

    2014-01-01

    We investigate numerically and experimentally highly efficient acoustic lenses based on the principle of extraordinary acoustic transmission. We study circular, flat lenses composed of perforated air channels. The geometry is similar to binary Fresnel lenses, and the lenses exploit several resonance mechanisms to enhance the transmission, such as Fabry–Perot resonances in the channels and cavity resonances on the lens surface. The proposed lenses are able to transmit up to 83% of the incident...

  2. Communication Acoustics

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....

  3. Optimal Design and Acoustic Assessment of Low-Vibration Rotor Blades

    G. Bernardini

    2016-01-01

    Full Text Available An optimal procedure for the design of rotor blade that generates low vibratory hub loads in nonaxial flow conditions is presented and applied to a helicopter rotor in forward flight, a condition where vibrations and noise become severe. Blade shape and structural properties are the design parameters to be identified within a binary genetic optimization algorithm under aeroelastic stability constraint. The process exploits an aeroelastic solver that is based on a nonlinear, beam-like model, suited for the analysis of arbitrary curved-elastic-axis blades, with the introduction of a surrogate wake inflow model for the analysis of sectional aerodynamic loads. Numerical results are presented to demonstrate the capability of the proposed approach to identify low vibratory hub loads rotor blades as well as to assess the robustness of solution at off-design operating conditions. Further, the aeroacoustic assessment of the rotor configurations determined is carried out in order to examine the impact of low-vibration blade design on the emitted noise field.

  4. Optical integration of Pancharatnam-Berry phase lens and dynamical phase lens

    Ke, Yougang; Liu, Yachao; Zhou, Junxiao; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-03-01

    In the optical system, most elements such as lens, prism, and optical fiber are made of silica glass. Therefore, integrating Pancharatnam-Berry phase elements into silica glass has potential applications in the optical system. In this paper, we take a lens, for example, which integrates a Pancharatnam-Berry phase lens into a conventional plano-convex lens. The spin states and positions of focal points can be modulated by controlling the polarization states of the incident beam. The proposed lens has a high transmission efficiency, and thereby acts as a simple and powerful tool to manipulate spin photons. Furthermore, the method can be conveniently extended to the optical fiber and laser cavity, and may provide a route to the design of the spin-photonic devices.

  5. Lens auto-centering

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève; Tremblay, Mathieu

    2015-09-01

    In a typical optical system, optical elements usually need to be precisely positioned and aligned to perform the correct optical function. This positioning and alignment involves securing the optical element in a holder or mount. Proper centering of an optical element with respect to the holder is a delicate operation that generally requires tight manufacturing tolerances or active alignment, resulting in costly optical assemblies. To optimize optical performance and minimize manufacturing cost, there is a need for a lens mounting method that could relax manufacturing tolerance, reduce assembly time and provide high centering accuracy. This paper presents a patent pending lens mounting method developed at INO that can be compared to the drop-in technique for its simplicity while providing the level of accuracy close to that achievable with techniques using a centering machine (usually innovative auto-centering method is based on the use of geometrical relationship between the lens diameter, the lens radius of curvature and the thread angle of the retaining ring. The autocentering principle and centering test results performed on real optical assemblies are presented. In addition to the low assembly time, high centering accuracy, and environmental robustness, the INO auto-centering method has the advantage of relaxing lens and barrel bore diameter tolerances as well as lens wedge tolerances. The use of this novel lens mounting method significantly reduces manufacturing and assembly costs for high performance optical systems. Large volume productions would especially benefit from this advancement in precision lens mounting, potentially providing a drastic cost reduction.

  6. Transparent Gradient-Index Lens for Underwater Sound Based on Phase Advance

    Martin, Theodore P.; Naify, Christina J.; Skerritt, Elizabeth A.; Layman, Christopher N.; Nicholas, Michael; Calvo, David C.; Orris, Gregory J.; Torrent, Daniel; Sánchez-Dehesa, José

    2015-09-01

    Spatial gradients in a refractive index are used extensively in acoustic metamaterial applications to control wave propagation through phase delay. This study reports the design and experimental realization of an acoustic gradient-index lens using a sonic crystal lattice that is impedance matched to water over a broad bandwidth. In contrast to previous designs, the underlying lattice features refractive indices that are lower than the water background, which facilitates propagation control based on a phase advance as opposed to a delay. The index gradient is achieved by varying the filling fraction of hollow, air-filled aluminum tubes that individually exhibit a higher sound speed than water and matched impedance. Acoustic focusing is observed over a broad bandwidth of frequencies in the homogenization limit of the lattice, with intensity magnifications in excess of 7 dB. An anisotropic lattice design facilitates a flat-faceted geometry with low backscattering at 18 dB below the incident sound-pressure level. A three-dimensional Rayleigh-Sommerfeld integration that accounts for the anisotropic refraction is used to accurately predict the experimentally measured focal patterns.

  7. Acoustic Neuroma

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. The tumor ... press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the symptoms ...

  8. Acoustic Neuroma

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  9. The influence of basic design variables on the acoustics of concert halls; new results derived from analysing a large number of existing halls

    Gade, Anders Christian

    1997-01-01

    A large data base over values of various room acoustic parameters has provided the basis for statistical analyses of how and how much the acoustic properties of conert halls are influenced by their size, shape and absorption area (as deduced from measured reverberation time). The data have been...... collected over a fifteen year period from about fifty concert halls in Europe and the US. In all halls the same measurement technique was used (1/1 octave sweep tones all pass filtered to form impulse responses per octave band). Due to the large range of geometric differences contained in the material, it...... has been possible to derive empirical regression formulae from which the influence of certain geometrical design variables can be quantified. The author has found these fairly simple relationships useful in teaching and as guide lines both in the early stages of physical hall design and in setting up...

  10. Design of tunable acoustic metamaterials through periodic arrays of resonant shunted piezos

    Periodic shunted piezoelectric patches are employed for the design of a tunable, one-dimensional metamaterial. The configuration considered encompasses a beam undergoing longitudinal and transverse motion, and a periodic array of piezoelectric patches with electrodes connected to a resonant electric circuit. The resulting acousto-electrical system is characterized by an internal resonant behavior that occurs at the tuning frequency of the shunting circuits, and is analogous in its operation to other internally resonating systems previously proposed, with the addition of its simple tunability. The performance of the beam is characterized through the application of the transfer matrix approach, which evaluates the occurrence of bandgaps at the tuning frequencies and estimates wave attenuation within such bands. Moreover, a homogenization study is conducted to illustrate the internal resonant characteristics of the system within an analytical framework. Experiments performed on the considered beam structure validate the theoretical predictions and illustrate its internal resonant characteristics and the formation of the related bandgaps. (paper)

  11. Rotman lens for mm-wavelengths

    Hall, Leonard T.; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The 77 GHz band has been reserved for intelligent cruise control in luxury cars and some public transport services in America and the United Kingdom. The Rotman lens offers a cheap and compact means to extend the single beam systems generally used, to fully functional beam staring arrangements. Rotman lenses have been built for microwave frequencies with limited success. The flexibility of microstrip transmission lines and the advent of fast accurate simulation packages allow practical Rotman lenses to be designed at mm-wavelengths. This paper discusses the limitations of the conventional design approach and predicts the performance of a new Rotman lens designed at 77 GHz.

  12. Anisotropic metamaterials for full control of acoustic waves.

    Christensen, Johan; García de Abajo, F Javier

    2012-03-23

    We study a class of acoustic metamaterials formed by layers of perforated plates and producing negative refraction and backward propagation of sound. A slab of such material is shown to act as a perfect acoustic lens, yielding images with subwavelength resolution over large distances. Our study constitutes a nontrivial extension of similar concepts from optics to acoustics, capable of sustaining negative refraction over extended angular ranges, with potential application to enhanced imaging for medical and detection purposes, acoustofluidics, and sonochemistry. PMID:22540586

  13. Architectural Acoustics Design of Wuxi Grand Theater Opera House%无锡大剧院歌剧厅的声学设计

    许荣林

    2014-01-01

    介绍江苏省无锡大剧院歌剧厅的建声设计技术指标及相关措施,并对其进行室内音质测试。%The technical norms and related measures of architectural acoustics design of Jiangsu Wuxi grand theatre opera house were introduced, along with testing its indoor sound quality.

  14. Ring lens for focusing ion beams to uniform densities

    An electrostatic lens was designed and built to focus a beam of positive ions into uniform density on a target. The lens has two concentric field regions with a grid separating the inner zero field from the outer radial field. For proper operation the incident ions must emanate with axial symmetry and Gaussian or similar divergence from a small source. An appendix is included on the symmetrization of elliptical beams by a quadrupole singlet lens. (U.S.)

  15. Modeling, design, packing and experimental analysis of liquid-phase shear-horizontal surface acoustic wave sensors

    Pollard, Thomas B

    Recent advances in microbiology, computational capabilities, and microelectromechanical-system fabrication techniques permit modeling, design, and fabrication of low-cost, miniature, sensitive and selective liquid-phase sensors and lab-on-a-chip systems. Such devices are expected to replace expensive, time-consuming, and bulky laboratory-based testing equipment. Potential applications for devices include: fluid characterization for material science and industry; chemical analysis in medicine and pharmacology; study of biological processes; food analysis; chemical kinetics analysis; and environmental monitoring. When combined with liquid-phase packaging, sensors based on surface-acoustic-wave (SAW) technology are considered strong candidates. For this reason such devices are focused on in this work; emphasis placed on device modeling and packaging for liquid-phase operation. Regarding modeling, topics considered include mode excitation efficiency of transducers; mode sensitivity based on guiding structure materials/geometries; and use of new piezoelectric materials. On packaging, topics considered include package interfacing with SAW devices, and minimization of packaging effects on device performance. In this work novel numerical models are theoretically developed and implemented to study propagation and transduction characteristics of sensor designs using wave/constitutive equations, Green's functions, and boundary/finite element methods. Using developed simulation tools that consider finite-thickness of all device electrodes, transduction efficiency for SAW transducers with neighboring uniform or periodic guiding electrodes is reported for the first time. Results indicate finite electrode thickness strongly affects efficiency. Using dense electrodes, efficiency is shown to approach 92% and 100% for uniform and periodic electrode guiding, respectively; yielding improved sensor detection limits. A numerical sensitivity analysis is presented targeting viscosity

  16. Tunable acoustic metamaterials

    Babaee, Sahab; Viard, Nicolas; Fang, Nicholas; Bertoldi, Katia

    2015-03-01

    We report a new class of active and switchable acoustic metamaterials composed of three-dimensional stretchable chiral helices arranged on a two-dimensional square lattice. We investigate the propagation of sounds through the proposed structure both numerically and experimentally and find that the deformation of the helices can be exploited as a novel and effective approach to control the propagation of acoustic waves. The proposed concept expands the ability of existing acoustic metamaterials since we demonstrate that the deformation can be exploited to turn on or off the band gap, opening avenues for the design of adaptive noise-cancelling devices.

  17. Refracting lens system for low-scatter star-tracker: A Concept

    1975-01-01

    ''Low Scatter Lens Design/Development'' discusses studies of low-scatter lens system. Two sections cover optical design and scattering analysis for model of lens system which rejects radiation. Result of computations are shown on computer printouts attached to report.

  18. Reflections From a Fresnel Lens

    Keeports, David

    2005-01-01

    Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

  19. Design of fully enclosed acoustic barrier of Yangze River Bridge in Yingwu continent of Wuhan city%武汉市鹦鹉洲长江大桥全封闭声屏障设计

    李明华

    2016-01-01

    根据声屏障声学原理,从建筑景观设计、结构设计、辅助设计等方面,探讨了武汉市鹦鹉洲长江大桥全封闭声屏障设计方法,并介绍了声屏障施工与维护措施,有效解决了高架道路交通噪声问题。%According to acoustical principle of acoustic barrier,starting from aspects of building landscape design,structural design and aided design,the paper explores design methods of fully enclosed acoustic barrier of Yangze River Bridge in Yingwu continent of Wuhan city,and intro-duces acoustic barrier construction and maintenance measures,which effectively solves elevated road traffic noise problem.

  20. Contact Lens Risks

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  1. Colored Contact Lens Dangers

    Full Text Available ... Sep 10, 2015 Contact Lens Horror Stories: Poor Care Can Lead to Blindness Sep 09, 2015 How to Correct High Myopia Feb 27, 2015 More Eye Health News Pet Fish Fitted with Fake Eye in ...

  2. Colored Contact Lens Dangers

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  3. Colored Contact Lens Dangers

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... placed on the eye can lower internal eye pressure by about 20 percent for half a year. ...

  4. Colored Contact Lens Dangers

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  5. Colored Contact Lens Dangers

    Full Text Available ... same level of care or consideration as a standard contact lens because they can be purchased over- ... lifestyle choices can directly affect your eyes. The best way to take care of your eyes during ...

  6. Colored Contact Lens Dangers

    Full Text Available ... lenses do not require the same level of care or consideration as a standard contact lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ...

  7. Capabilities, Design, Construction and Commissioning of New Vibration, Acoustic, and Electromagnetic Capabilities Added to the World's Largest Thermal Vacuum Chamber at NASA's Space Power Facility

    Motil, Susan M.; Ludwiczak, Damian R.; Carek, Gerald A.; Sorge, Richard N.; Free, James M.; Cikanek, Harry A., III

    2011-01-01

    NASA s human space exploration plans developed under the Exploration System Architecture Studies in 2005 included a Crew Exploration Vehicle launched on an Ares I launch vehicle. The mass of the Crew Exploration Vehicle and trajectory of the Ares I coupled with the need to be able to abort across a large percentage of the trajectory generated unprecedented testing requirements. A future lunar lander added to projected test requirements. In 2006, the basic test plan for Orion was developed. It included several types of environment tests typical of spacecraft development programs. These included thermal-vacuum, electromagnetic interference, mechanical vibration, and acoustic tests. Because of the size of the vehicle and unprecedented acoustics, NASA conducted an extensive assessment of options for testing, and as result, chose to augment the Space Power Facility at NASA Plum Brook Station, of the John H. Glenn Research Center to provide the needed test capabilities. The augmentation included designing and building the World s highest mass capable vibration table, the highest power large acoustic chamber, and adaptation of the existing World s largest thermal vacuum chamber as a reverberant electromagnetic interference test chamber. These augmentations were accomplished from 2007 through early 2011. Acceptance testing began in Spring 2011 and will be completed in the Fall of 2011. This paper provides an overview of the capabilities, design, construction and acceptance of this extraordinary facility.

  8. Designing acoustics for linguistically diverse classrooms: Effects of background noise, reverberation and talker foreign accent on speech comprehension by native and non-native English-speaking listeners

    Peng, Zhao Ellen

    The current classroom acoustics standard (ANSI S12.60-2010) recommends core learning spaces not to exceed background noise level (BNL) of 35 dBA and reverberation time (RT) of 0.6 second, based on speech intelligibility performance mainly by the native English-speaking population. Existing literature has not correlated these recommended values well with student learning outcomes. With a growing population of non-native English speakers in American classrooms, the special needs for perceiving degraded speech among non-native listeners, either due to realistic room acoustics or talker foreign accent, have not been addressed in the current standard. This research seeks to investigate the effects of BNL and RT on the comprehension of English speech from native English and native Mandarin Chinese talkers as perceived by native and non-native English listeners, and to provide acoustic design guidelines to supplement the existing standard. This dissertation presents two studies on the effects of RT and BNL on more realistic classroom learning experiences. How do native and non-native English-speaking listeners perform on speech comprehension tasks under adverse acoustic conditions, if the English speech is produced by talkers of native English (Study 1) versus native Mandarin Chinese (Study 2)? Speech comprehension materials were played back in a listening chamber to individual listeners: native and non-native English-speaking in Study 1; native English, native Mandarin Chinese, and other non-native English-speaking in Study 2. Each listener was screened for baseline English proficiency level, and completed dual tasks simultaneously involving speech comprehension and adaptive dot-tracing under 15 acoustic conditions, comprised of three BNL conditions (RC-30, 40, and 50) and five RT scenarios (0.4 to 1.2 seconds). The results show that BNL and RT negatively affect both objective performance and subjective perception of speech comprehension, more severely for non

  9. Modeling and Design of AlN Based SAW Device and Effect of Reflected Bulk Acoustic Wave Generated in the Device

    Saleem Khan

    2013-05-01

    Full Text Available Investigations of the effect of generation and reflection of bulk acoustic waves (BAWs on the performance surface acoustic wave (SAW device using finite element method (FEM simulation is carried out. A SAW delay line structure using Aluminum Nitride (AlN substrate is simulated. The dimension of the device is kept in the range of the 42  22.5 m in order to analyze the effect in MEMS devices. The propagation of the bulk wave in all the direction of the substrate is studied and analyzed. Since BAW reflect from the bottom of the SAW device and interfere with the receiving IDTs. The output of the SAW device is greatly affected by the interference of the BAW with SAWs in the device. Thus in SAW devices, BAW needed to be considered before designing the device.

  10. Acoustical Imaging

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  11. Patient acceptability of the Tecnis® multifocal intraocular lens

    Sood P

    2011-03-01

    Full Text Available Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus. The purpose of this review is to assess patient acceptability of the Tecnis® multifocal intraocular lens.Keywords: Tecnis®, intraocular lens, multifocal, presbyopia 

  12. Efficient flat metasurface lens for terahertz imaging.

    Yang, Quanlong; Gu, Jianqiang; Wang, Dongyang; Zhang, Xueqian; Tian, Zhen; Ouyang, Chunmei; Singh, Ranjan; Han, Jiaguang; Zhang, Weili

    2014-10-20

    Metamaterials offer exciting opportunities that enable precise control of amplitude, polarization and phase of the light beam at a subwavelength scale. A gradient metasurface consists of a class of anisotropic subwavelength metamaterial resonators that offer abrupt amplitude and phase changes, thus enabling new applications in optical device design such as ultrathin flat lenses. We propose a highly efficient gradient metasurface lens based on a metal-dielectric-metal structure that operates in the terahertz regime. The proposed structure consists of slotted metallic resonator arrays on two sides of a thin dielectric spacer. By varying the geometrical parameters, the metasurface lens efficiently manipulates the spatial distribution of the terahertz field and focuses the beam to a spot size on the order of a wavelength. The proposed flat metasurface lens design is polarization insensitive and works efficiently even at wide angles of incidence. PMID:25401626

  13. Simulation design and primary usage of corneal contact lens in rats%大鼠角膜接触镜的仿真研制及初步应用

    李俊岭; 周小煦; 宋艳萍; 赵育新; 李娜; 吴建国

    2011-01-01

    Objective To develop a rat corneal contact lens basing on simulation design and observe its primary effect for intravitreal injection. Methods The experiment was divided into 2 parts. Part 1: After the ocular physical parameters being measured, an adult SD rat eyeball model was designed by UG software. Then,the corresponding corneal contact lens model was designed by light Tools software and manufactured. Part 2:Twenty healthy adult SD rats treating intravitreal injection of bone marrow mes-enchymal stem cells (BMMSC) were randomly divided into 2 groups, the new corneal contact lens was used in group A( 10 rats, 10 eyes) and traditional methods of coverslip flattening the cornea in group B( 10 rats, 10 eyes). The experimental effect,complication and cost time were recorded and compared. All the operations were performed by the same person. Designed corneal contact lens was used in group A,and traditional cover glass was used to press cornea for completing operation in group B. Clear level of fun-dus image was recorded,the complete time and complications were compared between the two groups. Results The physical parameter of simulation-designed rat eyeball was similar to the results from foreign research works and the plastic contact lens was suit for all animals in this experiment. With the help of the new designed corneal contact lens,the posterior capsule of lens,vitreous and retina in rats were distinct and intravitreal injection was quickly achieved through two-hands assistance, the whole operation time cost( 192.50 ±22.51 )s in group A,whereas,the fundus images were not stable and the intravitreous injection was performed by single hand in group B, the operation time consumed(446.90 ±41.11 )s. There was a significant difference( t = - 17.17 ,P <0.01), and the time saved 254.40 s in group A. In additional, no complication occurred in group A, but 2 cases of lens injury occurred in group B, although there was no statistical differ-ence(P = 0. 273). Conclusions

  14. Room acoustic auralization with Ambisonics

    Polack, Jean-Dominique; Leão Figueiredo, Fábio

    2012-01-01

    International audience During the year of 2009, the room acoustics group of the LAM (Équipe Lutheries, Acoustique, Musique de l’Institut Jean Le Rond d’Alembert - Université Pierre et Marie Curie, Paris) performed a series of acoustical measurements in music halls in Paris. The halls were chosen in regarding their importance to the historic, architectural or acoustic domains. The measured ensemble of fourteen rooms includes quite different architectural designs. The measurements were carri...

  15. Effects of charge design features on parameters of acoustic and seismic waves and cratering, for SMR chemical surface explosions

    Gitterman, Y.

    2012-04-01

    time delays clearly separated for the shot of IMI explosives (characterized by much higher detonation velocity than ANFO). Additionally acoustic records at close distances from WSMR explosions Distant Image (2440 tons of ANFO) and Minor Uncle (2725 tons of ANFO) were used to extend the charge and distance range for the SS delay scaled relationship, that showed consistency with SMR ANFO shots. The developed specific charge design contributed to the success of this unique dual Sayarim explosion experiment, providing the strongest GT0 sources since the establishment of the IMS network, that demonstrated clearly the most favorable westward/ eastward infrasound propagation up to 3400/6250 km according to appropriate summer/winter weather pattern and stratospheric wind directions, respectively, and thus verified empirically common models of infrasound propagation in the atmosphere. The research was supported by the CTBTO, Vienna, and the Israel Ministry of Immigrant Absorption.

  16. Lens customization method to minimize aberration in integral imaging

    Miranda, Matheus; Kim, Jonghyun; Hong, Keehoon; Lee, Byoungho

    2015-10-01

    Conventionally the elemental lenses of the lens-array used in integral imaging have spherical surface profiles, thus they suffer from intrinsic lens aberrations such as spherical aberration and astigmatism. Aberrations affect the ability of the lens to focus light in a single point, or to collimate light from a point source. In integral imaging, this results in a loss of image quality of the reconstructed image due to distortions. The viewing characteristics of the integral imaging system, such as viewing angle and image resolution, are also affected by aberrations. We propose the use of a custom made aspherical lens-array which was specifically designed to minimize distortions due to aberrations and hence improve the reconstructed image quality. Ray optics calculations are used in order to analyze the aberrations and find the initial lens surface profile. Lens optimization is performed with the aid of numerical simulation software. The designed lens-array is compared to a conventional spherical lens-array of same properties. The design, optimization, and fabrication processes are described and the experiments are presented and compared with the computer simulations.

  17. Ares I Scale Model Acoustic Test Lift-Off Acoustics

    Counter, Douglas D.; Houston, Janie D.

    2011-01-01

    The lift-off acoustic (LOA) environment is an important design factor for any launch vehicle. For the Ares I vehicle, the LOA environments were derived by scaling flight data from other launch vehicles. The Ares I LOA predicted environments are compared to the Ares I Scale Model Acoustic Test (ASMAT) preliminary results.

  18. Rose-K versus soper contact lens in keratoconus: A randomized comparative trial

    Raghav Gupta

    2014-01-01

    Conclusion: Both the contact lens designs provide an equal improvement in visual acuity in patients with Keratoconus. However, Rose-K contact lens provides greater comfort, better quality of vision and requires less chair time compared with the Soper lens and hence may possibly have a greater acceptability.

  19. Multiplexer/demultiplexer in optical communications based on a holographic Fresnel lens

    A holographic Fresnel lens for coarse wavelength-division-multiplexing (WDM) application in 1300 nm band is described. Letter paper focuses on minimizing the third-order aberrations for off-axis operation of the lens in order to reduce channel spacing and insertion loss. Improved characteristics have been obtained for the lens fabricated according to the theoretical design

  20. Radiation acoustics

    Lyamshev, Leonid M

    2004-01-01

    Radiation acoustics is a developing field lying at the intersection of acoustics, high-energy physics, nuclear physics, and condensed matter physics. Radiation Acoustics is among the first books to address this promising field of study, and the first to collect all of the most significant results achieved since research in this area began in earnest in the 1970s.The book begins by reviewing the data on elementary particles, absorption of penetrating radiation in a substance, and the mechanisms of acoustic radiation excitation. The next seven chapters present a theoretical treatment of thermoradiation sound generation in condensed media under the action of modulated penetrating radiation and radiation pulses. The author explores particular features of the acoustic fields of moving thermoradiation sound sources, sound excitation by single high-energy particles, and the efficiency and optimal conditions of thermoradiation sound generation. Experimental results follow the theoretical discussions, and these clearl...

  1. The Principle and Method of Modern Landscape Acoustic Landscape Design%现代园林中声景观设计的原则与方法研究

    2013-01-01

      本文论述了园林声景观的形式及概念,并分析园林声景观设计中存在的问题、设计原则、设计程序与方法以及应注意的主要环节。最后提出了现代园林中声景观的设计手法,为现代园林声景观设计提供参考。%This paper discusses the form and concept of gard-en acoustic landscape, and makes the analysis of the existing acoustic landscape problems, design principles, design proced-ure and the method and the main points to be noticed in land-scape design. Finally, it puts forward the design methods of acoustic landscape in modern garden, provides the reference for the modern garden landscape design.

  2. Fabrication of an unusual mosaic lens

    The design philosophy and the construction techniques to make a novel mosaic lens to collect Cerenkow radiation are described. The lens blanks were rough cut into segments by a water jet. The segments were cut to the final inner and outer diameters by ultrasonically assisted machining, an unusual new technique developed at the Los Alamos National Laboratory. The technology will soon be available to the public through Sonic Mill, Inc., 3820 Academy Parkway North, NE, Albuquerque, N.M. 87109. The advantage of ultrasonically assisted machining lies in rapid, accurate shaping of brittle materials such as ceramics and glass, which can by this technique, be shaped about as fast as aluminum

  3. An "ESA-affordable" Laue-lens

    Lund, Niels

    rapidly. Telescopes based on Laue diffraction of gamma-rays from crystals appear as one promising route, although the practical difficulties of realizing a large scale Laue lens are certainly not small. In this paper I have attempted to develop an optimized lens design considering the size and mass......With ESA's INTEGRAL mission gamma-ray astronomy has advanced to the point where major scientific advances must be expected from detailed studies of the many new point sources. The interest in developing focusing telescopes operating in the soft gamma-ray regime up to 1 MeV is therefore mounting...

  4. Theoretical and experimental verification of acoustic focusing in metal cylinder structure

    Xia, Jian-ping; Sun, Hong-xiang; Cheng, Qian; Xu, Zheng; Chen, Hao; Yuan, Shou-qi; Zhang, Shu-yi; Ge, Yong; Guan, Yi-jun

    2016-05-01

    We report the realization of a multifocal acoustic focusing lens using a simple metal cylinder structure immersed in water, as determined both experimentally and theoretically. The acoustic waves can be focused on one or more points, because the Mie-resonance modes are excited in the cylinder structure. The acoustic pressure fields measured in the Schlieren imaging system agree with the results calculated using the acoustic scattering theory. Interesting applications of multifocal focusing in the acoustic encryption communication are further discussed. Our work should be helpful in understanding the focusing mechanism and experimentally measuring the acoustic phenomena in cylinder structures.

  5. Luneburg lens in silicon photonics

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-01-01

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms. (C) 2011 Optical Society of America

  6. Frequency selective lens antenna

    Thornton, J.; Haines, P.

    2007-01-01

    A variant of the hemispherical microwave lens antenna is reported where the ground plane region is modified through use of a frequency selective surface. This allows discrimination of frequencies by two closely spaced primary feeds. A scale model is reported operating at 12 and 30 GHz.

  7. Comparison of Strong Gravitational Lens Model Software II. HydraLens: Computer-Assisted Strong Gravitational Lens Model Generation and Translation

    Lefor, Alsn T

    2015-01-01

    The behavior of strong gravitational lens model software in the analysis of lens models is not necessarily consistent among the various software available, suggesting that the use of several models may enhance the understanding of the system being studied. Among the publicly available codes, the model input files are heterogeneous, making the creation of multiple models tedious. An enhanced method of creating model files and a method to easily create multiple models, may increase the number of comparison studies. HydraLens simplifies the creation of model files for four strong gravitational lens model software packages, including Lenstool, Gravlens/Lensmodel, glafic and PixeLens, using a custom designed GUI for each of the four codes that simplifies the entry of the model for each of these codes, obviating the need for user manuals to set the values of the many flags and in each data field. HydraLens is designed in a modular fashion, which simplifies the addition of other strong gravitational lens codes in th...

  8. Magnifying lens for 800 MeV proton radiography

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  9. 声悬浮及声速测定实验仪的设计%Acoustic levitation and design of sound velocity measurement instrument

    马国利

    2012-01-01

    《声速测定》是大学物理实验中比较普遍的一个综合性实验.在声速测定实验仪的基础上,改进了信号源,并制作了声悬浮配件,使其实现既可以用多种方式测量声速,又可演示声悬浮实验现象.声悬浮及声速测定实验仪悬浮稳定性强,声速测定准确,仪器造价低,使用方便,这样设计节省了实验室资源和空间.%The measurement of sound velocity is a commonly comprehensive experiment among university physics experiments. Our design idea is to, based on the original equipment, improve the signal source and make acoustic levitation parts so as to measure sound velocity in different ways; and demonstrate the experimental phenomena of acoustic levitation. The sound velocity measurement experiment instrument has strong levitation stability, accurate sound velocity measurement, low cost and convenient applications. This design saves laboratory resources and space.

  10. Battlefield acoustics

    Damarla, Thyagaraju

    2015-01-01

    This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

  11. Acoustical Imaging

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  12. Acoustic telemetry

    National Oceanic and Atmospheric Administration, Department of Commerce — To determine movements of green turtles in the nearshore foraging areas, we deployed acoustic tags and determined their movements through active and passive...

  13. Acoustics Research

    National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....

  14. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  15. Dielectric Optical-Controlled Magnifying Lens by Nonlinear Negative Refraction

    Cao, Jianjun; Zheng, Yuanlin; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

    2014-01-01

    A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive index. Recent advancements in nanotechnology enable novel lenses, such as, superlens, hyperlens, Luneburg lens, with sub-wavelength resolution capabilities by specially designing materials' refractive indices with meta-materials and transformation optics. However, these artificially nano/micro engineered lenses usually suffer high losses from metals and are highly demanding in fabrication. Here we experimentally demonstrate for the first time a nonlinear dielectric magnifying lens using negative refraction by degenerate four-wave mixing in a plano-concave glass slide, obtaining magnified images. Moreover, we transform a nonlinear flat lens into a magnifying lens by introducing transformation optics into nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applicat...

  16. Status of eye lens radiation dose monitoring in European hospitals.

    Carinou, Eleftheria; Ginjaume, Merce; O'Connor, Una; Kopec, Renata; Sans Merce, Marta

    2014-12-01

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. PMID:25222935

  17. Lens aberration measurement and analysis using a novel pattern

    Nam, Byung-Ho; Cho, Byeong-Ho; Park, Jong O.; Kim, Dong-Seok; Baek, SungJin; Jeong, JongHo; Nam, ByungSub; Hwang, Young J.; Song, Young Jin

    2001-09-01

    Lens aberration of the exposure tool causes pattern deformation and position shift. As design rule shrinks, the ratio of printed feature size to applied wavelength for optical lithography is driven inexorably toward resolution limit. In this study, we devised an efficient method to evaluate lens aberration using multi-ring pattern on an attenuated phase-shift mask. Adoption of multi-ring pattern can cut down measurement time and improve measurement repeatability. These patterns are uniformly distributed through entire field in 7 by 7 manner. Lens aberration was evaluated by multi-ring pattern array under conventional or off-axis illumination with KrF stepper of NA 0.65. Multi-ring critical dimension (CD) data was discussed together with the issue of lens aberration such as coma, astigmatism, field curvature, etc. We can apply this new measurement technique to select better lens system efficiently. multi-ring, field size, pattern deformation

  18. Status of eye lens radiation dose monitoring in European hospitals

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  19. Protection of the eye lens

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  20. Finite Element Analysis of the LOLA Receiver Telescope Lens

    Matzinger, Elizabeth

    2007-01-01

    This paper presents the finite element stress and distortion analysis completed on the Receiver Telescope lens of the Lunar Orbiter Laser Altimeter (LOLA). LOLA is one of six instruments on the Lunar Reconnaissance Orbiter (LRO), scheduled to launch in 2008. LOLA's main objective is to produce a high-resolution global lunar topographic model to aid in safe landings and enhance surface mobility in future exploration missions. The Receiver Telescope captures the laser pulses transmitted through a diffractive optical element (DOE) and reflected off the lunar surface. The largest lens of the Receiver Telescope, Lens 1, is a 150 mm diameter aspheric lens originally designed to be made of BK7 glass. The finite element model of the Receiver Telescope Lens 1 is comprised of solid elements and constrained in a manner consistent with the behavior of the mounting configuration of the Receiver Telescope tube. Twenty-one temperature load cases were mapped to the nodes based on thermal analysis completed by LOLA's lead thermal analyst, and loads were applied to simulate the preload applied from the ring flexure. The thermal environment of the baseline design (uncoated BK7 lens with no baffle) produces large radial and axial gradients in the lens. These large gradients create internal stresses that may lead to part failure, as well as significant bending that degrades optical performance. The high stresses and large distortions shown in the analysis precipitated a design change from BK7 glass to sapphire.

  1. Bioinspired solid-liquid mixed tunable lens with multilayered structure

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei

    2015-06-01

    A solid-liquid mixed tunable lens with multilayered structure is proposed. The designed lens utilizes a solid-state elastic polymer, optical liquid, and glass as the optical medium, and adjusts the focus by changing the surface curvature of the elastic polymer. The integrated structure of the tunable lens is presented, as well as detailed descriptions of the lens materials, fabrication, and assembling process. Images captured through the tunable lens under different displacement loads are presented, and the relationship among the displacement load, curvature radius, and effective focal length is analyzed. Additionally, the optical property of the tunable lens is simulated using the ZEMAX software. A change in focal length from 14.8 mm to 30 mm is demonstrated within the tiny 0.12 mm variation of the displacement load. Numerical analyses show that the lens distortion is less than 2%, and the modulation transfer function reaches 67 line pairs per mm. The solid-liquid mixed tunable lens shows the potential for developing a compact, low-aberration, and stable optical system.

  2. 某船舶结构声学设计技术探讨%Research on acoustic design of a certain ship structure

    王国治; 肖英龙; 方媛媛

    2014-01-01

    Aiming at the control of vibration and underwater noise of ship , an acoustic design technology of ship structure is discussed .On the basis of original structure design of the ship′s engine room , the vibration responses and the sound radiation under water were compared under different design parameters by using the method of FEM/BEM.An acoustic design was determined by adjusting the engine room structure parameters avoiding the happening of the hull structure resonance .Model test showed that the calculated value of vibration transfer char-acteristics had good consistency with the test results and the vibration noise prediction model established was credible .%以某船舶的噪声振动控制为目的,探讨了船舶结构声学设计技术。针对某船舶机舱结构,在初步设计的基础上,运用FEM/BEM方法,对比了不同设计参数下的船舶振动响应和水下辐射噪声声压级。通过调整机舱段结构参数,避免船体结构共振的发生,确定了低噪声设计方案。模型试验表明,振动传递特性的计算值与试验值有很好的一致性,所建立的船舶振动噪声预报模型是可信的。

  3. A single-pixel wireless contact lens display

    We present the design, construction and in vivo rabbit testing of a wirelessly powered contact lens display. The display consists of an antenna, a 500 × 500 µm2 silicon power harvesting and radio integrated circuit, metal interconnects, insulation layers and a 750 × 750 µm2 transparent sapphire chip containing a custom-designed micro-light emitting diode with peak emission at 475 nm, all integrated onto a contact lens. The display can be powered wirelessly from ∼1 m in free space and ∼2 cm in vivo on a rabbit. The display was tested on live, anesthetized rabbits with no observed adverse effect. In order to extend display capabilities, design and fabrication of micro-Fresnel lenses on a contact lens are presented to move toward a multipixel display that can be worn in the form of a contact lens. Contact lenses with integrated micro-Fresnel lenses were also tested on live rabbits and showed no adverse effect.

  4. Super-resolution imaging by resonant tunneling in anisotropic acoustic metamaterials.

    Liu, Aiping; Zhou, Xiaoming; Huang, Guoliang; Hu, Gengkai

    2012-10-01

    The resonant tunneling effects that could result in complete transmission of evanescent waves are examined in acoustic metamaterials of anisotropic effective mass. The tunneling conditions are first derived for the metamaterials composed of classical mass-in-mass structures. It is found that the tunneling transmission occurs when the total length of metamaterials is an integral number of half-wavelengths of the periodic Bloch wave. Due to the local resonance of building units of metamaterials, the Bloch waves are spatially modulated within the periodic structures, leading to the resonant tunneling occurring in the low-frequency region. The metamaterial slab lens with anisotropic effective mass is designed by which the physics of resonant tunneling and the features for evanescent field manipulations are examined. The designed lens interacts with evanescent waves in the way of the propagating wavenumber weakly dependent on the spatial frequency of evanescent waves. Full-wave simulations validate the imaging performance of the proposed lens with the spatial resolution beyond the diffraction limit. PMID:23039546

  5. Functional modular contact lens

    Shum, Angela J.; Cowan, Melissa; Lähdesmäki, Ilkka; Lingley, Andrew; Otis, Brian; Parviz, Babak A.

    2009-08-01

    Tear fluid offers a potential route for non-invasive sensing of physiological parameters. Utilization of this potential depends on the ability to manufacture sensors that can be placed on the surface of the eye. A contact lens makes a natural platform for such sensors, but contact lens polymers present a challenge for sensor fabrication. This paper describes a microfabrication process for constructing sensors that can be integrated into the structure of a functional contact lens in the future. To demonstrate the capabilities of the process, an amperometric glucose sensor was fabricated on a polymer substrate. The sensor consists of platinum working and counter electrodes, as well as a region of indium-tin oxide (ITO) for glucose oxidase immobilization. An external silver-silver chloride electrode was used as the reference electrode during the characterization experiments. Sensor operation was validated by hydrogen peroxide measurements in the 10- 20 μM range and glucose measurements in the 0.125-20 mM range.

  6. Introducing passive acoustic filter in acoustic based condition monitoring: Motor bike piston-bore fault identification

    Jena, D. P.; Panigrahi, S. N.

    2016-03-01

    Requirement of designing a sophisticated digital band-pass filter in acoustic based condition monitoring has been eliminated by introducing a passive acoustic filter in the present work. So far, no one has attempted to explore the possibility of implementing passive acoustic filters in acoustic based condition monitoring as a pre-conditioner. In order to enhance the acoustic based condition monitoring, a passive acoustic band-pass filter has been designed and deployed. Towards achieving an efficient band-pass acoustic filter, a generalized design methodology has been proposed to design and optimize the desired acoustic filter using multiple filter components in series. An appropriate objective function has been identified for genetic algorithm (GA) based optimization technique with multiple design constraints. In addition, the sturdiness of the proposed method has been demonstrated in designing a band-pass filter by using an n-branch Quincke tube, a high pass filter and multiple Helmholtz resonators. The performance of the designed acoustic band-pass filter has been shown by investigating the piston-bore defect of a motor-bike using engine noise signature. On the introducing a passive acoustic filter in acoustic based condition monitoring reveals the enhancement in machine learning based fault identification practice significantly. This is also a first attempt of its own kind.

  7. Valveless micropump driven by acoustic streaming

    This paper describes two valveless micropumps built on a 260 µm thick PZT with 20 µm thick parylene acoustic Fresnel lenses with air cavities. The micropumps produce in-plane body force through acoustic streaming effect of high-intensity acoustic beam that is generated by acoustic wave interference. The fabricated micropumps were shown to move microspheres, which have a diameter of 70–90 µm and a density of 0.99 g cm−3, on the water surface to form U-shape streams of microspheres with a drift velocity of 7.3 cm s−1 when the micropumps were located 4 mm below the water surface and driven by 160 Vpeak-to-peak pulsed sinusoidal waves. The driven microspheres formed U-shape streaming even without any fluidic channel according to the serial connection of the pie-shaped lenses and top electrodes. A micropump with a straight-lined fluidic channel was also fabricated and tested to show a 9.2 cm s−1 microspheres' drift velocity and a 9.5 mL min−1 volume pumping rate when combined with the acrylic acoustic wave reflector. Both the Fresnel lens and top electrode were patterned in a pie-shape with its apex angle of 90° to form asymmetric acoustic pressure distribution at the focal plane of the acoustic Fresnel lenses in order to push water in one direction. (paper)

  8. Silicone oil-intraocular lens interaction: which lens to use?

    McLoone, E; Mahon, G; Archer, D.; Best, R

    2001-01-01

    AIM—To determine a suitable intraocular lens for implantation in patients at high risk of lens exposure to silicone oil in their lifetime.
METHODS—PMMA, AcrySof, AR40, AQUA-Sense, and Raysoft lenses were examined. Each lens was immersed for 5 minute intervals in balanced salt solution (BSS), in stained silicone oil, and again in BSS before being photographed in air and in BSS. Percentage silicone oil coverage of the lens optic was determined.
RESULTS—The mean percentage coating (MPC) for the ...

  9. 音乐厅舞台音质与声学设计%Concert-hall stage acoustics and its design

    王季卿

    2015-01-01

    舞台音质对音乐厅演出效果起重要作用。为了使全乐队演出协调,乐师们要求听好自己的和来自其他演员的声音。因此,为使所有器乐和歌声达到适当平衡,以取得良好的合奏效果,将涉及到舞台设施、乐器特征以及如何把声音合适地反射给乐师们。此外,根据乐师主观意见选用恰当的客观声学参量很重要,同时还要考虑用怎样的建筑措施使之实现。这项研究历史较短,不少问题有待探索。文章对此作了综述与评论。%Stage acoustics dominates concert hall performance conditions. Musicians performing on stage, instrumen-tal and vocal, require an appropriate balance of sounds, including their own, to achieve a good sense of ensemble. The balance normally depends on the stage set up, properties of the instruments, and the availability of surfaces redirecting the sounds back to musicians. From comparison between subjective research and objective measurements, some acous-tical measures and a set of proposed architectural treatments were conducted and suggested accordingly. The paper summarizes major contributions on this field and a general overview of this subject is presented.

  10. Research of the long-focus Maksutov telephoto lens

    Tarasov, I. P.; Tsyganok, E. A.

    2016-04-01

    The article presents the research result and the optical design of long-focus telephoto lens for photo shooting by the academician Maksutov's scheme. It shows a review of lenses for photo shooting on the market today, and also an analysis of the correctional possibilities which is based on the scheme is presented; studied long-focus telephoto lens is compared with its closest analog, the calculation of a new telephoto lens with higher image quality is made on the basis of that comparison.

  11. Development of a Fresnel lens concentrator for space application

    Oneill, Mark J.; Piszczor, Michael F.

    1987-01-01

    The selected conceptual design of the dome lens photovoltaic concentrator for space applications uses a 3.7 cm square aperture dome lens to focus onto a 0.4 cm active diameter gallium arsenide cell. The selected configuration will provide 91.5 percent lens optical efficiency and 21.4 percent cell efficiency at 100 suns irradiance and 100 C cell temperature, for an overall cell efficiency of 19.6 percent. The selected configuration will tolerate 1 degree tracking errors with negligible loss of performance. The selected panel weight is 2.5 kg/sq.m.

  12. The Optimal Gravitational Lens Telescope

    Surdej, J; Coleman, P; Dominik, M; Habraken, S; Hanot, C; Coroller, H Le; Mawet, D; Quintana, H; Sadibekova, T; Sluse, D; 10.1088/0004-6256/139/5/1935

    2010-01-01

    Given an observed gravitational lens mirage produced by a foreground deflector (cf. galaxy, quasar, cluster,...), it is possible via numerical lens inversion to retrieve the real source image, taking full advantage of the magnifying power of the cosmic lens. This has been achieved in the past for several remarkable gravitational lens systems. Instead, we propose here to invert an observed multiply imaged source directly at the telescope using an ad-hoc optical instrument which is described in the present paper. Compared to the previous method, this should allow one to detect fainter source features as well as to use such an optimal gravitational lens telescope to explore even fainter objects located behind and near the lens. Laboratory and numerical experiments illustrate this new approach.

  13. Acoustic emission

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  14. Characterization of acoustic lenses with the Foucault test by confocal laser scanning microscopy

    Ahmed Mohamed, E. T.; Abdelrahman, A.; Pluta, M.; Grill, W.

    2010-03-01

    In this work, the Foucault knife-edge test, which has traditionally been known as the classic test for optical imaging devices, is used to characterize an acoustic lens for operation at 1.2 GHz. A confocal laser scanning microscope (CLSM) was used as the illumination and detection device utilizing its pinhole instead of the classical knife edge that is normally employed in the Foucault test. Information about the geometrical characteristics, such as the half opening angle of the acoustic lens, were determined as well as the quality of the calotte of the lens used for focusing. The smallest focal spot size that could be achieved with the examined lens employed as a spherical reflector was found to be about 1 μm. By comparison to the idealized resolution a degradation of about a factor of 2 can be deduced. This limits the actual quality of the acoustic focus.

  15. Advances in lens implant technology

    Kook, Daniel; Kampik, Anselm; Dexl, Alois K.; Zimmermann, Nicole; Glasser, Adrian; Baumeister, Martin; Kohnen, Thomas

    2013-01-01

    Cataract surgery is one of the oldest and the most frequent outpatient clinic operations in medicine performed worldwide. The clouded human crystalline lens is replaced by an artificial intraocular lens implanted into the capsular bag. During the last six decades, cataract surgery has undergone rapid development from a traumatic, manual surgical procedure with implantation of a simple lens to a minimally invasive intervention increasingly assisted by high technology and a broad variety of imp...

  16. Connexin hemichannels in the lens

    EricCBeyer

    2014-01-01

    The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemi-channel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have been detected in isolated lens fiber cells. These hemichannels may make significant contributio...

  17. Connexin hemichannels in the lens

    Beyer, Eric C.; Berthoud, Viviana M.

    2014-01-01

    The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemichannel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have been detected in isolated lens fiber cells. These hemichannels may make significant contributions t...

  18. Self retaining contact lens system for vitreous surgery

    Chalam Kakarla

    2004-01-01

    Full Text Available We describe the principle and design of a new self-retaining contact lens system for vitreous surgery. The system has three lenses: the plano-concave, prism and magnifying lens. This system is based on the principle of a direct imaging contact lens, designed for a 150-200mm focal length operating microscope. The contact lenses are designed to have an inferior concave surface [radius of curvature (ROC 7.7mm], modified by the addition of four footplates to provide stability and centration during vitreous surgery. The lenses are used with a drop of viscoelastic material placed between the concave surface of the contact lens and cornea. This induces negative suction and helps retain the lens in position during surgery. These specially designed lenses provide a stable, well-centered, high-resolution, magnified view of the fundus. This system eliminates the need for a skilled assistant or for suturing the lens to the sclera during vitreous surgery.

  19. Design process of a dual mass flywheel with consideration of an acoustic optimization of the powertrain system; Entwicklungsprozess eines ZMS mit Fokus auf akustische Antriebsstrangoptimierung

    Fischer, Michael; Grieshofer, Oliver; Schober, Martin [Magna Powertrain, Engineering Center Steyr, St. Valentin (Austria)

    2011-07-01

    Powertrain systems of vehicles with combustion engines are expected to be reliable during the life-time as well as providing optimized acoustic properties for the ride comfort. Due to the current developments for the reduction of fuel consumption, cyclic irregularities of engines increase and thus stand in contradiction with the premises for drivetrains. An improvement can be achieved by implementing a dual mass flywheel that transfers the engine power but isolates the cyclic irregularity. MAGNA Powertrain-Engineering Center Steyr has developed a dual mass flywheel with a new concept, that combines the advantages of low dissipation losses with a variable transfer behaviour. The challenging development process is described in this article and includes simulations for design optimization as well as measurements on the test bench and on the real vehicle to verify the performance and reliable operation. (orig.)

  20. Dispersion-compensated fresnel lens

    Johnson, Kenneth C.

    1992-01-01

    A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4.multidot.10.sup.-5 inch and a profile width of at least 10.sup.-3 inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight.

  1. 中央电视台新址工程建筑声学设计概述%Brief Account of Architectural Acoustics Design for Project of CCTV on the New Site

    王静波

    2013-01-01

    在总体探讨广播电视建筑中声学设计与应用的基础上,以新建的中国中央电视台(CCTV)工程为例,对这一超大型的广播电视建筑中,各类不同功能空间的建筑声学设计做了相关的概述,探讨了一些高标准声学用房在结构声学和室内声学方面的措施.%Based on the study of acoustics design and application on radio-television building, and taking the new CCTV project as example, this paper gives relevant account of architectural acoustics design for spaces of different function in the super large radio-television building. For some high level acoustic spaces, it explores the technical measures on structural acoustics and indoor acoustics.

  2. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  3. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-07-20

    The Portable Acoustic Monitoring Package (PAMP) has been designed to record and monitor the acoustic signal in natural gas transmission lines. In particular the three acoustic signals associated with a line leak. The system is portable ({approx}30 lbs) and is designed for line pressures up to 1000 psi. It has become apparent that cataloging of the various background acoustic signals in natural gas transmission line is very important if a system to identify leak signals is to be developed. The low-pressure (0-200 psig) laboratory test phase has been completed and a number of field trials have been conducted. Before the cataloging phase could begin, a few problems identified in field trials identified had to be corrected such as: (1) Decreased microphone sensitivity at line pressures above 250 psig. (2) The inability to deal with large data sets collected when cataloging the variety of signals in a transmission line. (3) The lack of an available online acoustic calibration system. These problems have been solved and the WVU PAMP is now fully functional over the entire pressure range found in the Natural Gas transmission lines in this region. Field portability and reliability have been greatly improved. Data collection and storage have also improved to the point were the full acoustic spectrum of acoustic signals can be accurately cataloged, recorded and described.

  4. Integrating the human factors characterization of disabled users in a design method. Application to an interface for playing acoustic music

    Veytizou, Julien; Magnier, Cécile; Villeneuve, François; THOMANN, Guillaume

    2012-01-01

    International audience Users and uses inclusion in product design remains a challenge, especially when their characterization is very specific, which is the case with disabled persons. Many design methodologies integrating user exist, for example, User-Centered Design (UCD). The application of these methodologies results in custom product designs, but they haven't objective the motor activities characterization of stakeholders: people with disabilities. Our ambition is to characterize and ...

  5. Development of lens sutures.

    Kuszak, Jer R; Zoltoski, Rebecca K; Tiedemann, Clifford E

    2004-01-01

    Cylindrical map projections (CMPs) have been used for centuries as an effective means of plotting the features of a 3D spheroidal surfaces (e.g. the earth) on a 2D rectangular map. We have used CMPs to plot primate fiber cell organization from selected growth shells as a function of growth, development and aging. Lens structural parameters and features were derived from slit-lamp, light and transmission and scanning electron micrographs. This information was then used to create CMPs of lenses that were then correlated with azimuthal map projections (AMPs; projections that are radially symmetric around a central point [the poles]) to reveal different suture patterns during distinct time periods. In this manner, both lens fiber and suture branch locations are defined by degrees of longitude and latitude. CMPs and AMPs confirm that throughout defined periods of development, growth and ageing, increasingly complex suture patterns are formed by the precise ordering of straight and opposite end curvature fibers. However, the manner in which additional suture branches are formed anteriorly and posteriorly is not identical. Anteriorly, new branches are added between extant branches. Posteriorly, pairs of new branches are formed that progressively overlay extant branches. The advantage of using CMPs is that the shape and organization of every fiber in a growth shell can be observed in a single image. Thus, the use of CMPs to plot primate fiber cell organization has revealed more complex aspects of fiber formation that may explain, at least in part, changes in lens optical quality as a function of age and pathology. In addition, more accurate measurements of fiber length will be possible by incorporating the latitudinal and longitudinal locations of fibers. PMID:15558480

  6. Luneburg lens composed of sunflower-type graded photonic Crystals

    Sun, Xiao-Hong; Wu, Yu-Long; Liu, Wei; Hao, Yu; Jiang, Liu-Di

    2014-03-01

    Sunflower-type graded photonic crystals (GPCs) are investigated and used to design the Luneburg lens for transverse electric (TE) and transverse-magnetic (TM) polarizations. Our investigation suggests that these novel structures present better focusing characteristics as well as wider transmission bandwidth for TM polarization than that for TE polarization. It is envisaged that these sunflower-type GPCs can be potentially used in optical system where compact and powerful focusing elements are required such as the Luneburg lens.

  7. Dielectric Optical-Controlled Magnifying Lens by Nonlinear Negative Refraction

    Cao, Jianjun; Shang, Ce; Zheng, Yuanlin; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

    2014-01-01

    A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive index. Recent advancements in nanotechnology enable novel lenses, such as, superlens, hyperlens, Luneburg lens, with sub-wavelength resolution capabilities by specially designing materials' refractive indices with meta-materials and transformation optics. However, these artificially nano/micro engineered lenses usually suffe...

  8. Patient acceptability of the Tecnis® multifocal intraocular lens

    Woodward, Maria

    2011-01-01

    Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL) designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anter...

  9. Design of copper/carbon-coated fiber Bragg grating acoustic sensor net for integrated health monitoring of nuclear power plant

    Research highlights: → We develop a cost-effective fiber Bragg grating (FBG) acoustic sensor net for nuclear power plants using copper/carbon (Cu/C)-coated fiber. → A chemical method is proposed to remove the Cu/C coating. A 5 mm FBG is successfully inscribed in a Ge-doped silica core through a 7 mm-long silica section with the coating removed. → The Cu/C-coated fiber net shows good thermal resistance (oC). → The Cu/C-coated FBG sensor using the metallic adhesive successfully detects the acousto-ultrasonic waves generated by pencil lead breaking and laser beam excitation. - Abstract: A nuclear power plant (NPP) is a harsh environment that gives rise to age-related degradation of the plant structures, and eventually leads to radiation leakage that threatens humans. Integrated structural health monitoring (ISHM) technology is a strong candidate for the prevention of the NPP accidents during operation. Prior studies have shown that fiber Bragg gratings (FBGs) and metal-coated fibers have good radiation and high temperature resistance. In this study, a FBG acoustic sensor using a metallic adhesive for installation and a relatively economical copper/carbon (Cu/C)-coated fiber is developed for ISHM of high temperature NPP structures. A chemical method is proposed to remove the Cu/C coating. A 5 mm FBG was successfully inscribed in a Ge-doped silica core through a 7 mm-long silica section with the coating removed. The Cu/C-coated fiber with the same core/clad structure as the standard SMF allowed no-loss fusion splicing, and showed good adaptability to the economical standard fiber, adaptor, connector, and instruments. It showed also good thermal resistance (oC) with no degradation in optical power during the optical transmission. The metallic adhesive used to install the FBG in a one-end-free configuration showed superior bonding reliability during temperature cycles ranging from 25 oC to 345 oC. The FBG reflectivity was stabilized at a 58% drop from the initial

  10. A stereoscopic lens for digital cinema cameras

    Lipton, Lenny; Rupkalvis, John

    2015-03-01

    Live-action stereoscopic feature films are, for the most part, produced using a costly post-production process to convert planar cinematography into stereo-pair images and are only occasionally shot stereoscopically using bulky dual-cameras that are adaptations of the Ramsdell rig. The stereoscopic lens design described here might very well encourage more live-action image capture because it uses standard digital cinema cameras and workflow to save time and money.

  11. Lens of Eye Dosimetry

    Mallett, Michael Wesley [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-23

    An analysis of LANL occupational dose measurements was made with respect to lens of eye dose (LOE), in particular, for plutonium workers. Table 1 shows the reported LOE as a ratio of the “deep” (photon only) and “deep+neutron” dose for routine monitored workers at LANL for the past ten years. The data compares the mean and range of these values for plutonium workers* and non-routine plutonium workers. All doses were reported based on measurements with the LANL Model 8823 TLD.

  12. Diffractive Alvarez lens

    A diffractive Alvarez lens is demonstrated that consists of two separate phase plates, each having complementary 16-level surface-relief profiles that contain cubic phase delays. Translation of these two components in the plane of the phase plates is shown to produce a variable astigmatic focus. Both spherical and cylindrical phase profiles are demonstrated with good accuracy, and the discrete surface-relief features are shown to cause less than λ/10 wave-front aberration in the transmitted wave front over a 40 mmx80 mm region. (c) 2000 Optical Society of America

  13. Miniaturized high-resolution wide-field contact lens for panretinal photocoagulation

    Koushan K

    2014-04-01

    Full Text Available Keyvan Koushan, KV Chalam Department of Ophthalmology, University of Florida College of Medicine, Jacksonville, FL, USA Background and objective: We describe a miniaturized lightweight high-refractive-index panretinal contact lens for diagnostic and therapeutic visualization of the peripheral retina. Instrument design: The miniaturized high-resolution wide-field contact lens includes three optical elements in a light (15 g and miniaturized (16 mm footplate, 24 mm external aperture, and 21 mm vertical height casing contributing to a total dioptric power of +171 diopters. This lens provides up to 165° visualization of the retina for diagnostic and therapeutic applications while allowing easier placement due to its miniaturization. Conclusion: This new lens (50% lighter and 89% smaller improves upon earlier contact lenses for visualization of the peripheral retina. Keywords: contact lens, panretinal photocoagulation, retinal examination, peripheral retina, high resolution view, wide-angle lens, lens

  14. Noise Shielding Using Acoustic Metamaterials

    We exploit theoretically a class of rectangular cylindrical devices for noise shielding by using acoustic metamaterials. The function of noise shielding is justified by both the far-field and near-field full-wave simulations based on the finite element method. The enlargement of equivalent acoustic scattering cross sections is revealed to be the physical mechanism for this function. This work makes it possible to design a window with both noise shielding and air flow. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  15. Challenges of using dielectric elastomer actuators to tune liquid lens

    Keong, Gih-Keong; La, Thanh-Giang; Shiau, Li-Lynn; Tan, Adrian W. Y.

    2014-03-01

    Recently, dielectric elastomer actuators (DEAs) have been adopted to tune liquid membrane lens, just like ciliary muscles do to the lens in human eye. However, it faces some challenges, such as high stress, membrane puncture, high driving voltage requirement, and limited focus distance (not more than 707cm), that limit its practical use. The design problem gets more complex as the liquid lens shares the same elastomeric membrane as the DEA. To address these challenges, we separate DEA from the lens membrane. Instead, a liquid-immersed DEA, which is safe from terminal failure, is used as a diaphragm pump to inflate or deflate the liquid lens by hydraulic pressure. This opens up the possibility that the DEA can be thinned down and stacked up to reduce the driving voltage, independent of the lens membrane thickness. Preliminary study showed that our 8-mm-diameter tunable lens can focus objects in the range of 15cm to 50cm with a small driving voltage of 1.8kV. Further miniaturization of DEA could achieve a driving voltage less than 1kV.

  16. Control of low-frequency noise for piping systems via the design of coupled band gap of acoustic metamaterials

    Li, Yanfei; Shen, Huijie; Zhang, Linke; Su, Yongsheng; Yu, Dianlong

    2016-07-01

    Acoustic wave propagation and sound transmission in a metamaterial-based piping system with Helmholtz resonator (HR) attached periodically are studied. A transfer matrix method is developed to conduct the investigation. Calculational results show that the introduction of periodic HRs in the piping system could generate a band gap (BG) near the resonant frequency of the HR, such that the bandwidth and the attenuation effect of HR improved notably. Bragg type gaps are also exist in the system due to the systematic periodicity. By plotting the BG as functions of HR parameters, the effect of resonator parameters on the BG behavior, including bandwidth, location and attenuation performance, etc., is examined. It is found that Bragg-type gap would interplay with the resonant-type gap under some special situations, thereby giving rise to a super-wide coupled gap. Further, explicit formulation for BG exact coupling is extracted and some key parameters on modulating the width and the attenuation coefficient of coupled gaps are investigated. The coupled gap can be located to any frequency range as one concerned, thus rendering the low-frequency noise control feasible in a broad band range.

  17. Elasticity imaging of speckle-free tissue regions with moving acoustic radiation force and phase-sensitive optical coherence tomography

    Hsieh, Bao-Yu; Song, Shaozhen; Nguyen, Thu-Mai; Yoon, Soon Joon; Shen, Tueng; Wang, Ruikang; O'Donnell, Matthew

    2016-03-01

    Phase-sensitive optical coherence tomography (PhS-OCT) can be utilized for quantitative shear-wave elastography using speckle tracking. However, current approaches cannot directly reconstruct elastic properties in speckle-less or speckle-free regions, for example within the crystalline lens in ophthalmology. Investigating the elasticity of the crystalline lens could improve understanding and help manage presbyopia-related pathologies that change biomechanical properties. We propose to reconstruct the elastic properties in speckle-less regions by sequentially launching shear waves with moving acoustic radiation force (mARF), and then detecting the displacement at a specific speckle-generating position, or limited set of positions, with PhS-OCT. A linear ultrasound array (with a center frequency of 5 MHz) interfaced with a programmable imaging system was designed to launch shear waves by mARF. Acoustic sources were electronically translated to launch shear waves at laterally shifted positions, where displacements were detected by speckle tracking images produced by PhS-OCT operating in M-B mode with a 125-kHz A-line rate. Local displacements were calculated and stitched together sequentially based on the distance between the acoustic source and the detection beam. Shear wave speed, and the associated elasticity map, were then reconstructed based on a time-of-flight algorithm. In this study, moving-source shear wave elasticity imaging (SWEI) can highlight a stiff inclusion within an otherwise homogeneous phantom but with a CNR increased by 3.15 dB compared to a similar image reconstructed with moving-detector SWEI. Partial speckle-free phantoms were also investigated to demonstrate that the moving-source sequence could reconstruct the elastic properties of speckle-free regions. Results show that harder inclusions within the speckle-free region can be detected, suggesting that this imaging method may be able to detect the elastic properties of the crystalline lens.

  18. Software for the design of acoustical steam silencers of the reaction-absorption type; Software para el diseno de silenciadores acusticos de vapor del tipo reaccion-absorcion

    Buendia Dominguez, Eduardo H.; Alvarez Chavez, Jose M. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    This paper describes the computer program named SILRA, that determines the outline dimensions of an acoustic steam silencer of the reaction-absorption type. These silencers are employed in the geothermoelectric power plants to lower the high levels of pressure and sound caused by the steam discharge to the surrounding atmosphere. The program has the capacity of predicting the noise level generated by the discharge without silencer depending on the emitting source. On SIRLA was successfully coupled the theory described in specialized literature with optimization techniques and experiences acquired in former designs. SIRLA is a powerful tool that allows the designer to optimize the equipment as well as the design time. [Espanol] En este trabajo se describe el programa de computo SILRA, que determina las dimensiones generales de un silenciador acustico de vapor tipo reaccion-absorcion, estos silenciadores se emplean en las centrales geotermoelectricas para abatir los altos niveles de presion de sonido provocados por la descarga del vapor a la atmosfera. El programa tiene la capacidad de predecir el nivel de ruido que genera la descarga sin silenciador, dependiendo de la fuente emisora. En SILRA se acoplaron con exito la teoria descrita en la literatura especializada con tecnicas de optimacion y experiencias adquiridas en disenos anteriores. SILRA es una poderosa herramienta que permite al disenador optimar tanto el equipo como el tiempo de diseno.

  19. Design and Simulation of Underwater Acoustic Communication System Based on QPSK Modulation%基于 QPSK 调制水声通信系统设计与仿真

    张国龙; 郑琛瑶

    2015-01-01

    论文研究了水声通信系统的组成原理及各部分功能,结合水声通信信道特性对水声通信系统的影响,研究并提出了用QPSK调制技术设计水声通信系统。确立了水声通信系统数学模型,以Matlab为工具对整个系统进行仿真分析,通过理论研究和仿真可以发现,QPSK调制技术在水声通信中的应用可以有效抑制多径扩展和海洋噪声,减少误码率,确保水声通信的可靠性,提高通信速率。%This paper studies the principle of underwater acoustic communication system components and the parts fea‐ture ,and proposes to use QPSK modulation technique to design underwater acoustic communication system combining with the impact of underwater acoustic communication channel characteristics of underwater acoustic communication system .The mathematical model of underwater acoustic communication system is established ,and the whole system is simulated and ana‐lyzed with Matlab .Through theoretical studies and simulation ,it is found that QPSK modulation techniques can effectively inhibite multipath expansion in underwater acoustic communication applications ,reduce the error rate of ocean noise ,ensure the reliability of underwater acoustic communication ,and improve communication rate .

  20. Acoustic methodology review

    Schlegel, R. G.

    1982-01-01

    It is important for industry and NASA to assess the status of acoustic design technology for predicting and controlling helicopter external noise in order for a meaningful research program to be formulated which will address this problem. The prediction methodologies available to the designer and the acoustic engineer are three-fold. First is what has been described as a first principle analysis. This analysis approach attempts to remove any empiricism from the analysis process and deals with a theoretical mechanism approach to predicting the noise. The second approach attempts to combine first principle methodology (when available) with empirical data to formulate source predictors which can be combined to predict vehicle levels. The third is an empirical analysis, which attempts to generalize measured trends into a vehicle noise prediction method. This paper will briefly address each.

  1. Rose-K contact lens for keratoconus

    Jain Arun

    2007-01-01

    Full Text Available Aim: To report clinical experience and the comparative value of axial and instantaneous topography data in fitting Rose-K design contact lenses in moderate and severe keratoconus. Materials and Methods: Thirty-eight eyes (of 23 patients with keratoconus were fitted with Rose-K design contact lenses and followed up for at least six months or more. Visual acuity with habitual vision correction available was measured. Axial and instantaneous topography maps for each eye were recorded. Contact lens wear comfort was graded on a ten point rating scale every three months. Results: Fourteen (100% moderate keratoconus eyes (average Sim K 48.61 ± 1.24D and 23 of 24 (96% of severe keratoconus eyes (average Sim K 60.88 ± 5.31D were successfully fitted with the Rose-K lenses. Final fit contact lenses in severe keratoconus had statistically significant steeper base curves compared to average axial corneal curvature than in moderate keratoconus eyes. Average simulated corneal curvature on axial maps predicted final fit contact lens base curves significantly better than on instantaneous maps. Thirty-three of the 37 eyes fitted with contact lenses maintained wear comfort over average follow up period of 13 ± 3.5 months. Conclusions: Rose-K design rigid contact lenses are successful in visually rehabilitating 100% of moderate and 96% of severe keratoconus eyes. Most patients (90% maintained contact lens wear comfort. Corneal curvature on axial maps is a better predictive of base curve of final fit contact lens.

  2. Critical Assessment of Correction Methods for Fisheye Lens Distortion

    Liu, Y.; Tian, C.; Huang, Y.

    2016-06-01

    A fisheye lens is widely used to create a wide panoramic or hemispherical image. It is an ultra wide-angle lens that produces strong visual distortion. The distortion modeling and estimation of the fisheye lens are the crucial step for fisheye lens calibration and image rectification in computer vision and close-range photography. There are two kinds of distortion: radial and tangential distortion. Radial distortion is large for fisheye imaging and critical for the subsequent image processing. Although many researchers have developed calibration algorithms of radial distortion of fisheye lens, quantitative evaluation of the correction performance has remained a challenge. This is the first paper that intuitively and objectively evaluates the performance of five different calibration algorithms. Upto- date research on fisheye lens calibration is comprehensively reviewed to identify the research need. To differentiate their performance in terms of precision and ease-using, five methods are then tested using a diverse set of actual images of the checkerboard that are taken at Wuhan University, China under varying lighting conditions, shadows, and shooting angles. The method of rational function model, which was generally used for wide-angle lens correction, outperforms the other methods. However, the one parameter division model is easy for practical use without compromising too much the precision. The reason is that it depends on the linear structure in the image and requires no preceding calibration. It is a tradeoff between correction precision and ease-using. By critically assessing the strengths and limitations of the existing algorithms, the paper provides valuable insight and guideline for future practice and algorithm development that are important for fisheye lens calibration. It is promising for the optimal design of lens correction models that are suitable for the millions of portable imaging devices.

  3. Design of Hartmann type null screens for testing a plano-convex aspheric lens with a CCD sensor inside the caustic.

    Castillo-Santiago, Gabriel; Castán-Ricaño, Diana; Avendaño-Alejo, Maximino; Castañeda, Luis; Díaz-Uribe, Rufino

    2016-08-22

    A new method to design Hartmann type null screens to test either qualitatively or quantitatively fast plano-convex aspherical lenses is presented. We design both radial and square null screens that produce arrays of circular spots uniformly distributed at predefined planes, considering that the CCD sensor is solely placed inside the caustic region. The designs of these null screens are based on knowledge of the caustic by refraction and on exact ray tracing. The null screens also serve to improve the alignment in optical systems. PMID:27557218

  4. Dielectric Optical-Controllable Magnifying Lens by Nonlinear Negative Refraction

    Cao, Jianjun; Shang, Ce; Zheng, Yuanlin; Feng, Yaming; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

    2015-07-01

    A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive indices. Recent advancements in nanotechnology enable novel lenses, such as, superlens and hyperlens, with sub-wavelength resolution capabilities by specially designed materials’ refractive indices with meta-materials and transformation optics. However, these artificially nano- or micro-engineered lenses usually suffer high losses from metals and are highly demanding in fabrication. Here, we experimentally demonstrate, for the first time, a nonlinear dielectric magnifying lens using negative refraction by degenerate four-wave mixing in a plano-concave glass slide, obtaining magnified images. Moreover, we transform a nonlinear flat lens into a magnifying lens by introducing transformation optics into the nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applications in microscopy and imaging science.

  5. Plasma lens experiments at the Final Focus Test Beam

    Barletta, B. [California Univ., Los Angeles, CA (United States)]|[Lawrence Berkeley Lab., CA (United States); Chattopadhyay, S. [Lawrence Berkeley Lab., CA (United States); Chen, P. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 {times} 10{sup 10}, tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  6. Controlling sound with acoustic metamaterials

    Cummer, Steven A.; Christensen, Johan; Alù, Andrea

    2016-03-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales. The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create effective material properties that are not possible with passive structures and have led to the development of dynamically reconfigurable, loss-compensating and parity-time-symmetric materials for sound manipulation. Challenges remain, including the development of efficient techniques for fabricating large-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview of future directions in the field.

  7. Design and Modelling of a Two-port Surface Acoustic WaveResonator using Coupling-of-modes Theory

    Mamta Khaneja

    2008-05-01

    Full Text Available In this present paper the coupling-of-modes theory has been used to design and simulatethe characteristics of a two-port SAW resonator with shorted reflection gratings to define theresonance cavity. A resonator device at 150 MHz has been designed and fabricated on ST-Quartz. It is found that the simulated and experimental characteristics of the device are in closeagreement. The results show that the SAW designs based on coupling-of-modes formulationare adequate for most applications.

  8. Prototype color field sequential television lens assembly

    1974-01-01

    The design, development, and evaluation of a prototype modular lens assembly with a self-contained field sequential color wheel is presented. The design of a color wheel of maximum efficiency, the selection of spectral filters, and the design of a quiet, efficient wheel drive system are included. Design tradeoffs considered for each aspect of the modular assembly are discussed. Emphasis is placed on achieving a design which can be attached directly to an unmodified camera, thus permitting use of the assembly in evaluating various candidate camera and sensor designs. A technique is described which permits maintaining high optical efficiency with an unmodified camera. A motor synchronization system is developed which requires only the vertical synchronization signal as a reference frequency input. Equations and tradeoff curves are developed to permit optimizing the filter wheel aperture shapes for a variety of different design conditions.

  9. Through the lens of instructional design: appraisal of the Jeffries/National League for Nursing Simulation Framework for use in acute care.

    Wilson, Rebecca D; Hagler, Debra

    2012-09-01

    As human patient simulation becomes more prevalent in acute care settings, clinical experts are often asked to assist in developing scenarios. Although the Jeffries/National League for Nursing Simulation Framework has been used in academic settings to guide the instructional design of clinical simulations, its use in acute care settings is less known. This framework incorporates a consideration of contextual elements, design characteristics, and outcomes. An external validation study applying the framework within the context of acute care showed its overall strength as well as elements that were problematic. The implications derived from the study of the design characteristics in a hospital setting can be used by nurses who are considering either adopting or adapting this framework for their own practice. PMID:22715871

  10. Generation of dark hollow beam by focusing a sine-Gaussian beam using a cylindrical lens and a focusing lens

    Tang, Huiqin; Zhu, Kaicheng

    2013-12-01

    Based on the generalized Huygens-Fresnel diffraction integral, a closed-form propagation equation related to sine-Gaussian beams through a cylindrical lens and a focusing lens is derived and illustrated with numerical methods. It is found that a sine-Gaussian beam through such a system may be converted into a dark hollow beam (DHB) with topological charge index one and its bright enclosure is approximately an elongated ellipse with very high ellipticity. Moreover, the parameter values at which the DHBs have perfect intensity patterns are designed. The optimal relative orientation between the dislocation line of the input sine-Gaussian beam and the axial orientation of the cylindrical lens is specified. And the ellipticity of the elliptical DHBs is mainly defined by the focal length of the cylindrical lens and the Fresnel number of the optical system.

  11. Acoustic fault injection tool (AFIT)

    Schoess, Jeffrey N.

    1999-05-01

    On September 18, 1997, Honeywell Technology Center (HTC) successfully completed a three-week flight test of its rotor acoustic monitoring system (RAMS) at Patuxent River Flight Test Center. This flight test was the culmination of an ambitious 38-month proof-of-concept effort directed at demonstrating the feasibility of detecting crack propagation in helicopter rotor components. The program was funded as part of the U.S. Navy's Air Vehicle Diagnostic Systems (AVDS) program. Reductions in Navy maintenance budgets and available personnel have dictated the need to transition from time-based to 'condition-based' maintenance. Achieving this will require new enabling diagnostic technologies. The application of acoustic emission for the early detection of helicopter rotor head dynamic component faults has proven the feasibility of the technology. The flight-test results demonstrated that stress-wave acoustic emission technology can detect signals equivalent to small fatigue cracks in rotor head components and can do so across the rotating articulated rotor head joints and in the presence of other background acoustic noise generated during flight operation. During the RAMS flight test, 12 test flights were flown from which 25 Gbyte of digital acoustic data and about 15 hours of analog flight data recorder (FDR) data were collected from the eight on-rotor acoustic sensors. The focus of this paper is to describe the CH-46 flight-test configuration and present design details about a new innovative machinery diagnostic technology called acoustic fault injection. This technology involves the injection of acoustic sound into machinery to assess health and characterize operational status. The paper will also address the development of the Acoustic Fault Injection Tool (AFIT), which was successfully demonstrated during the CH-46 flight tests.

  12. Analysis of a time-lens based optical frame synchronizer and retimer for 10G Ethernet aiming at a Tb/s optical router/switch design

    Laguardia Areal, Janaina; Hu, Hao; Peucheret, Christophe;

    2010-01-01

    This paper analyzes experimentally and by numerical simulations an optical frame retimer and synchronizer unit for 10 Gbit/s Ethernet input frames. The unit is envisaged to be applied in the design of an optically transparent router for Optical Time Division Multiplexed (OTDM) links, aggregating...

  13. A contact lens with embedded sensor for monitoring tear glucose level

    Yao, Huanfen; Shum, Angela J.; Cowan, Melissa; Lähdesmäki, Ilkka; Parviz, Babak A.

    2010-01-01

    We report the design, construction, and testing of a contact lens with an integrated amperometric glucose sensor, proposing the possibility of in situ human health monitoring simply by wearing a contact lens. The glucose sensor was constructed by creating microstructures on a polymer substrate, which was subsequently shaped into a contact lens. Titania sol-gel film was applied to immobilize glucose oxidase, and Nafion® was used to decrease several potential interferences (ascorbic acid, lacta...

  14. THE DESIGN OF AUDITORIUM DEPENDING ON THE INTERACTION BETWEEN ARCHITECTURE AND ACOUSTICS%协作的艺术——建筑与声学互动下的演艺建筑观众厅设计

    程翌

    2012-01-01

    By analyzing the cases of new venues around the world, this paper tries to illustrate the new design approach of auditorium depending on the modern acoustic technology. This paper paints out that the design of auditorium is a collaboration arts: the space concept of architects should start with the acoustic concept, while, acoustic consultants could inspire the new acoustic idea from the bold originality of architects.%本文通过对全球新建演艺建筑的案例分析,来探讨在现代声学技术支持下,观众厅设计的新方式。指出观众厅的设计是一个协作的艺术,建筑师的空间设计以声学概念为起点:而声学顾问能因建筑师的大胆创意而激发出声学新概念。

  15. Topology optimization for acoustic problems

    Dühring, Maria Bayard

    In this paper a method to control acoustic properties in a room with topology optimization is presented. It is shown how the squared sound pressure amplitude in a certain part of a room can be minimized by distribution of material in a design domain along the ceiling in 2D and 3D. Nice 0-1 designs...

  16. Acoustic Mechanical Feedthroughs

    Sherrit, Stewart; Walkemeyer, Phillip; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea

    2013-01-01

    Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be

  17. Seeing industrial services through experience lens - Revealing a customer experience map to design for an experiential service in B2B context

    Hu, Yue

    2016-01-01

    Nowadays, more and more companies become aware of the importance on experience investment, which not only brings customers pleasant and meaningful interactions during the business but also supports the company to formulate key brand differentiator compared to other competitors. Through the theoretical background research, it has been found that there is still a lack of academic studies and design cases about investigating industrial services with experiential thinking in business-to-business ...

  18. Photothermal Lens Aberration Effects in Two Laser Thermal Lens Spectrometry

    Bialkowski, Stephen E.

    1985-01-01

    A comparison of theories describing two laser photothermal lens signals is given. The aberrant nature of this lens is accounted for in a theory which treats the propagation of a monitor laser in terms of a phase shift in this laser beam wave front. The difference between theories are discussed in terms of the predicted signal strengths and temporal behavior. The aberrant theory results in smaller theoretical signal strengths and different functional relationships between signal and analyte le...

  19. Handbook of optical design

    Malacara-Hernández, Daniel

    2013-01-01

    Handbook of Optical Design, Third Edition covers the fundamental principles of geometric optics and their application to lens design in one volume. It incorporates classic aspects of lens design along with important modern methods, tools, and instruments, including contemporary astronomical telescopes, Gaussian beams, and computer lens design. Written by respected researchers, the book has been extensively classroom-tested and developed in their lens design courses. This well-illustrated handbook clearly and concisely explains the intricacies of optical system design and evaluation. It also di

  20. Zoned near-zero refractive index fishnet lens antenna: Steering millimeter waves

    A zoned fishnet metamaterial lens is designed, fabricated, and experimentally demonstrated at millimeter wavelengths to work as a negative near-zero refractive index lens suitable for compact lens antenna configurations. At the design frequency f = 56.7 GHz (λ0 = 5.29 mm), the zoned fishnet metamaterial lens, designed to have a focal length FL = 9λ0, exhibits a refractive index n = −0.25. The focusing performance of the diffractive optical element is briefly compared with that of a non-zoned fishnet metamaterial lens and an isotropic homogeneous zoned lens made of a material with the same refractive index. Experimental and numerically-computed radiation diagrams of the fabricated zoned lens are presented and compared in detail with that of a simulated non-zoned lens. Simulation and experimental results are in good agreement, demonstrating an enhancement generated by the zoned lens of 10.7 dB, corresponding to a gain of 12.26 dB. Moreover, beam steering capability of the structure by shifting the feeder on the xz-plane is demonstrated

  1. Zoned near-zero refractive index fishnet lens antenna: Steering millimeter waves

    Pacheco-Peña, V., E-mail: victor.pacheco@unavarra.es; Orazbayev, B., E-mail: b.orazbayev@unavarra.es; Beaskoetxea, U., E-mail: unai.beaskoetxea@unavarra.es; Beruete, M., E-mail: miguel.beruete@unavarra.es [TERALAB (MmW—THz—IR and Plasmonics Laboratory), Universidad Pública de Navarra, Campus Arrosadía, 31006 Pamplona (Spain); Navarro-Cía, M., E-mail: m.navarro@imperial.ac.uk [Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2BT (United Kingdom); Centre for Plasmonics and Metamaterials, Imperial College London, London SW7 2AZ (United Kingdom); Centre for Terahertz Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom)

    2014-03-28

    A zoned fishnet metamaterial lens is designed, fabricated, and experimentally demonstrated at millimeter wavelengths to work as a negative near-zero refractive index lens suitable for compact lens antenna configurations. At the design frequency f = 56.7 GHz (λ{sub 0} = 5.29 mm), the zoned fishnet metamaterial lens, designed to have a focal length FL = 9λ{sub 0}, exhibits a refractive index n = −0.25. The focusing performance of the diffractive optical element is briefly compared with that of a non-zoned fishnet metamaterial lens and an isotropic homogeneous zoned lens made of a material with the same refractive index. Experimental and numerically-computed radiation diagrams of the fabricated zoned lens are presented and compared in detail with that of a simulated non-zoned lens. Simulation and experimental results are in good agreement, demonstrating an enhancement generated by the zoned lens of 10.7 dB, corresponding to a gain of 12.26 dB. Moreover, beam steering capability of the structure by shifting the feeder on the xz-plane is demonstrated.

  2. Lightweight Inexpensive Ozone Lidar Telescope Using a Plastic Fresnel Lens

    DeYoung, Russell J.; Notari, Anthony; Carrion, William; Pliutau, Denis

    2014-01-01

    An inexpensive lightweight ozone lidar telescope was designed, constructed and operated during an ozone lidar field campaign. This report summarizes the design parameters and performance of the plastic Fresnel lens telescope and shows the ozone lidar performance compared to Zemax calculations.

  3. Bionic optical imaging system with aspheric solid-liquid mixed variable-focus lens

    Du, Jia-Wei; Wang, Xuan-Yin; Liang, Dan

    2016-02-01

    A bionic optical imaging system with an aspheric solid-liquid mixed variable-focus lens was designed and fabricated. The entire system mainly consisted of a doublet lens, a solid-liquid mixed variable-focus lens, a connecting part, and a CCD imaging device. To mimic the structure of the crystalline lens, the solid-liquid mixed variable-focus lens consisted of a polydimethylsiloxane (PDMS) lens, a polymethyl methacrylate lens, and the liquid of ethyl silicone oil. By pumping liquid in or out of the cavity using a microinjector, the curvatures of the front and rear surfaces of the PDMS lens were varied, resulting in a change of focal length. The overall structure of the system was presented, as well as a detailed description of the solid-liquid mixed variable-focus lens, material, and fabrication process. Under different injection volumes, the deformation of the PDMS lens was measured and simulated, pictures were captured, and the optical performance was analyzed in simulations and experiments. The focal length of the system ranged from 25.05 to 14.61 mm, and the variation of the diopter was 28.5D, which was larger than that of the human eye.

  4. Adjustable hybrid diffractive/refractive achromatic lens

    Valley, Pouria; Savidis, Nickolaos; Schwiegerling, Jim; Dodge, Mohammad Reza; Peyman, Gholam; N. Peyghambarian

    2011-01-01

    We demonstrate a variable focal length achromatic lens that consists of a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping po...

  5. Refractive lens for hard x-rays

    The refractive lens for hard X-rays on the base of glass capillary is presented. The fabrication techniques for lens production are described. The model of refractive lens for hard X-ray is proposed. The model assume that the compound lens work similar one thin lens the complex refraction index of which is following: n=1-δ N + i β N. On the base of this model the parameters of focussed beam are calculated and the images of object are constructed

  6. Contact Lens Related Corneal Ulcer

    Loh, KY; P Agarwal

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  7. Evaluation of resources for contact lens practice in private contact lens clinics of Muscat, Oman

    Rajiv Khandekar; Mohammed Al Fahdi

    2009-01-01

    Background: The integration of the contact lens (CL) practice with the VISION 2020 initiative is important. We assessed the facilities at the private CL clinics of Muscat. Accordingly, we suggested the appropriate eye care for CL wearers in Oman. Study Design: This was a descriptive study. Materials and Methods: This study was conducted between May and July 2006. A team of optometrists and health inspectors visited clinics and collected information about the infrastructure, available hu...

  8. Acoustic transducer for nuclear reactor monitoring

    Disclosed is a transducer to monitor a parameter and produce an acoustic signal from which the monitored parameter can be recovered. The transducer comprises a modified Galton whistle which emits a narrow band acoustic signal having a frequency dependent upon the parameter being monitored, such as the temperature of the cooling media of a nuclear reactor. Multiple locations within a reactor are monitored simultaneously by a remote acoustic receiver by providing a plurality of transducers each designed so that the acoustic signal it emits has a frequency distinct from the frequencies of signals emitted by the other transducers, whereby each signal can be unambiguously related to a particular transducer. 8 claims, 1 figure

  9. Gabor lens theory

    The principle of using the space charge of an electron cloud to focus ion beams was first proposed by Gabor. Electrons are to be confined radially by means of an axial magnetic field B/sub z/ and axially by means of externally applied electric fields E/sub z/. An ion beam of charge density n/sub i/ much less than n/sub e/, the electron charge density can then be focused by the radial electric field set up by the electron cloud. The case considered here is that of a hollow cylindrical conductor charged to a potential +V with grounded rings on either side to set up the axial E/sub z/ field. A solenoid wound around the central conductor supplies the B/sub z/ field. Theoretical calculations are carried out for n/sub e/ maximum as a function of B/sub z/ due to radial confinement and V due to axial confinement and the focal length of the Gabor Lens is calculated

  10. Fabrication of Miniaturized Variable-focus Lens Using Liquid Filling Technique

    Yang, Hsiharng; Yeh, Mau-Shiun

    2008-01-01

    This paper describes a simple method for fabricating a variable-focus lens by using PDMS (polydimethylsiloxane) and filling with liquid for the variable-focus lens. The lens diameter of 2-mm was designed in this experiment and expected to reach the focal length in the range of 3 ~ 12 mm. The theoretical value between the liquid volume and the lens contact angle at different focal lengths were simulated and measured. The pumped-in volumes ranged from 200 to 1400 $\\mu$l, the contact angles ranged from 14.25 degrees to 49.02 degrees. Changing the deformation of PDMS film using different micro-fluidic volume produces the variable focal length from 4 10 mm in this experiment. The proposed method successfully fabricated a variable-focus lens. Bonding PDMS only once using no expensive instrument such as oxygen plasma was accomplished. The final objective is to insert the variable focus lens into portable optical imagery products.

  11. Integration of Acoustic Detection Equipment into ANTARES

    Lahmann, R; Graf, K; Hoessl, J; Kappes, A; Karg, T; Katz, U; Naumann, C; Salomon, K

    2005-01-01

    The ANTARES group at the University of Erlangen is working towards the integration of a set of acoustic sensors into the ANTARES Neutrino Telescope. With this setup, tests of acoustic particle detection methods and background studies shall be performed. The ANTARES Neutrino Telescope, which is currently being constructed in the Mediterranean Sea, will be equipped with the infrastructure to accommodate a 3-dimensional array of photomultipliers for the detection of Cherenkov light. Within this infrastructure, the required resources for acoustic sensors are available: Bandwidth for the transmission of the acoustic data to the shore, electrical power for the off-shore electronics and physical space to install the acoustic sensors and to route the connecting cables (transmitting signals and power) into the electronics containers. It will be explained how the integration will be performed with minimal modifications of the existing ANTARES design and which setup is foreseen for the acquisition of the acoustic data.

  12. Acoustics in rock and pop music halls

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues in...

  13. A planar lens based on the electrowetting of two immiscible liquids

    This paper reports the development and characterization of a planar liquid lens based on electrowetting. The working concept of electrowetting two immiscible liquids is demonstrated with measurement and characterization of contact angles with regard to externally applied electric voltages. Consequently, a planar liquid lens is designed and implemented based on this competitive electrowetting. A droplet of silicone oil confined in an aqueous solution (1% KCl) works as a liquid lens. Electrowetting then controls the shape of the confined silicone oil and the focal length of the liquid lens varies depending upon an applied dc voltage. A unique feature of this lens design is the double-ring planar electrodes beneath the hydrophobic substrate. While an outer ring electrode provides an initial boundary for the silicone oil droplet, an inner ring works as the actuation electrode for the lens. Further, the planar electrodes, instead of vertical or out-of-plane wall electrodes, facilitate the integration of liquid lenses into microfluidic systems. With the voltage applied in the range of 50–250 V, the confined silicone oil droplet changed its shape and the optical magnification of a 3 mm-diameter liquid lens was clearly demonstrated. Moreover, focal lengths of liquid lenses with diameters of 2 mm, 3 mm and 4 mm were characterized, respectively. The obtained results suggest that a larger lens diameter yields a longer focal length and a wider range of focal length change in response to voltage. The demonstrated liquid lens has a simple structure and is easy to fabricate

  14. Manufacturing injection-moleded Fresnel lens parquets for point-focus concentrating photovoltaic systems

    Peters, E.M.; Masso, J.D. [AOtec, Southbridge, MA (United States)

    1995-10-01

    This project involved the manufacturing of curved-faceted, injection-molded, four-element Fresnel lens parquets for concentrating photovoltaic arrays. Previous efforts showed that high-efficiency (greater than 82%) Fresnel concentrators could be injection molded. This report encompasses the mold design, molding, and physical testing of a four-lens parquet for a solar photovoltaic concentrator system.

  15. Sensitivity of imaging properties of metal-dielectric layered flat lens to fabrication inaccuracies

    Kotynski, R.; Baghdasaryan, H.; Stefaniuk, T.;

    2010-01-01

    We characterize the sensitivity of imaging properties of a layered silver-TiO2 flat lens to fabrication inaccuracies. The lens is designed for approximately diffraction-free imaging with subwavelength resolution at distances in the order of a wavelength. Its operation may be attributed to self...

  16. An electrostatic deceleration lens for highly charged ions

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar8+, extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved.

  17. Broadband Wide Angle Lens Implemented with Dielectric Metamaterials

    Anthony Starr

    2011-08-01

    Full Text Available The Luneburg lens is a powerful imaging device, exhibiting aberration free focusing for parallel rays incident from any direction. However, its advantages are offset by a focal surface that is spherical and thus difficult to integrate with standard planar detector and emitter arrays. Using the recently developed technique of transformation optics, it is possible to transform the curved focal surface to a flat plane while maintaining the perfect focusing behavior of the Luneburg over a wide field of view. Here we apply these techniques to a lesser-known refractive Luneburg lens and implement the design with a metamaterial composed of a semi-crystalline distribution of holes drilled in a dielectric. In addition, we investigate the aberrations introduced by various approximations made in the implementation of the lens. The resulting design approach has improved mechanical strength with small aberrations and is ideally suited to implementation at infrared and visible wavelengths.

  18. An electrostatic deceleration lens for highly charged ions.

    Rajput, J; Roy, A; Kanjilal, D; Ahuja, R; Safvan, C P

    2010-04-01

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar(8+), extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved. PMID:20441330

  19. Acoustic hemostasis

    Crum, L.; Andrew, M.; Bailey, M.; Beach, K.; Brayman, A.; Curra, F.; Kaczkowski, P.; Kargl, S.; Martin, R.; Vaezy, S.

    2003-04-01

    Over the past several years, the Center for Industrial and Medical Ultrasound (CIMU) at the Applied Physics Laboratory in the University of Washington has undertaken a broad research program in the general area of High Intensity Focused Ultrasound (HIFU). Our principal emphasis has been on the use of HIFU to induce hemostasis; in particular, CIMU has sought to develop a small, lightweight, portable device that would use ultrasound for both imaging and therapy. Such a technology is needed because nearly 50% of combat casualty mortality results from exsanguinations, or uncontrolled bleeding. A similar percentage occurs for civilian death due to trauma. In this general review, a presentation of the general problem will be given, as well as our recent approaches to the development of an image-guided, transcutaneous, acoustic hemostasis device. [Work supported in part by the USAMRMC, ONR and the NIH.

  20. Acoustic propagation in viscous fluid with uniform flow and a novel design methodology for ultrasonic flow meter.

    Chen, Yong; Huang, Yiyong; Chen, Xiaoqian

    2013-02-01

    Ultrasonic flow meter with non-invasive no-moving-parts construction has good prospective application for space on-orbit fluid gauging. In traditional pulse transit time flow meter, inconsistency of ultrasonic transducers leads to measurement error and plane wave theory, bases of transit time flow meter, is valuable only for low-frequency wave propagation in inviscid fluid and will lose feasibility when fluid viscosity is considered. In this paper, based on the hydrodynamics of viscous fluid, wave propagation with uniform flow profile is mathematically formulated and a novel solution for viscous fluid using potential theory is firstly presented. Then a novel design methodology of continuous ultrasonic flow meter is proposed, where high measurement rangeability and accuracy are guaranteed individually by solving the integral ambiguity using multi-tone wide laning strategy and the fractional phase shift using phase lock loop tracking method. A comparison with transit time ultrasonic flow meter shows the advantage of proposed methodology. In the end, parametric analysis of viscosity on wave propagation and ultrasonic flow meter is compressively investigated. PMID:23146176

  1. The design of underwater acoustic signal sample and memory system based on uClinux%基于uClinux的嵌入式水声信号采集存储系统设计

    支绍龙; 吴玉泉; 尹力; 黄海宁

    2011-01-01

    为了减少水声学研究和水声工程设计试验的时间、成本等,针对水声信号和系统工作环境的特点,设计并实现了一种基于嵌入式uClinux操作系统的水声信号采集存储系统.发挥了处理器对外部设备优秀的控制能力和uClinux操作系统出色的稳定性两大优势,使系统稳定、可靠、低功耗、便捷地工作.通过海试验证了数据的有效性,证明系统具有实用价值.%In consideration of feature of underwater acoustic and working condition, to reduce time and cost of underwater acoustic research and experiment, a design of sample-memory system of underwater acoustic signal based on uClinux is proposed. This design uses the combination of the excellent control of CPU and the stable performance of uClinux to obtain stable, reliable, low cost, convenient work abilities. The data memorized is proved effective and the design is practical through experiment.

  2. Acoustic telemetry.

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  3. Acoustic Neuroma Educational Video

    Full Text Available Educational Video Home What is an AN What is an Acoustic Neuroma? Identifying an AN Symptoms Acoustic Neuroma Keywords Educational Video ... for pre- and post-treatment acoustic neuroma patients. Home What is an AN What is an Acoustic ...

  4. Use of acoustic vortices in acoustic levitation

    Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller

    2009-01-01

    Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...

  5. Acoustic Emission Health Monitoring of Fill Purge COPV's Used in Aerospace and Automotive Applications and Designed for Long Cycle Life

    Waller, Jess

    2013-01-01

    Cumulative composite damage in composite pressure vessels (CPVs) currently is not monitored on-orbit. Consequently, hazards due to catastrophic burst before leak (BBL) or compromised CPV reliability cannot be ascertained or mitigated, posing a risk to crew and mission assurance. The energy associated with CPV rupture can be significant, especially with high pressure gases are under containment, and the energy releases can be severe enough to cause injury, death, loss of assets or mission. Dual-Use Rationale: CPVs similar to those used by NASA on ISS, for example, are finding increasing use in automotive and transportation industry applications. These CPVs generally have a nonload sharing liner and are repeatedly filled over their service lifetime, typically with hydrogen or compressed natural gas (CNG). The same structural health monitoring equipment and software developed by NASA WSTF for evaluating, in real-time, the health of NASA CPVs on ISS will be used to evaluate the health of automotive CPVs, the only differences being the type and design of the CPV, and the in-service lifetime pressure histories. HSF Need(s)/Performance Characteristic(s) Supported: 1) Enable on-board vehicle systems management for mission critical functions at destinations with > 3 second time delay 2) Enable autonomous nominal operations and FDIR for crewed and un-crewed systems 3) Reduce on-board crew time to sustain and manage vehicle by factor of 2x at destinations with > 6 second time delay (see Crew Autonomy sheet) 4) Reduce earth-based mission ops "back room engineering" requirements for distant mission support delay (see Mission Autonomy sheet)

  6. High transmission acoustic focusing by impedance-matched acoustic meta-surfaces

    Al Jahdali, Rasha

    2016-01-19

    Impedance is an important issue in the design of acoustic lenses because mismatched impedance is detrimental to real focusing applications. Here, we report two designs of acoustic lenses that focus acoustic waves in water and air, respectively. They are tailored by acoustic meta-surfaces, which are rigid thin plates decorated with periodically distributed sub-wavelength slits. Their respective building blocks are constructed from the coiling-up spaces in water and the layered structures in air. Analytic analysis based on coupled-mode theory and transfer matrix reveals that the impedances of the lenses are matched to those of the background media. With these impedance-matched acoustic lenses, we demonstrate the acoustic focusing effect by finite-element simulations.

  7. My 65 years in acoustics

    Beranek, Leo L.

    2001-05-01

    My entry into acoustics began as research assistant to Professor F. V. Hunt at Harvard University. I received my doctorate in 1940 and directed the Electro-Acoustic Laboratory at Harvard from October 1940 until September 1945. In 1947, I became a tenured associate professor at MIT, and, with Richard H. Bolt, formed the consulting firm Bolt and Beranek, that later included Robert B. Newman, becoming BBN. My most significant contributions before 1970 were design of wedge-lined anechoic chambers, systemization of noise reduction in ventilation systems, design of the world's largest muffler for the testing of supersonic jet engines at NASA's Lewis Laboratory in Cleveland, speech interference level, NC noise criterion curves, heading New York Port Authority's noise study that resulted in mufflers on jet aircraft, and steep aircraft climb procedures, and publishing books titled, Acoustical Measurements, Acoustics, Noise Reduction, Noise and Vibration Control, and Music, Acoustics and Architecture. As President of BBN, I supervised the formation of the group that built and operated the ARPANET (1969), which, when split in two (using TCP/IP protocol) became the INTERNET (1984). Since then, I have written two books on Concert Halls and Opera Houses and have consulted on four concert halls and an opera house.

  8. Adaptable Design Improvements for Electromagnetic Shock Wave Lithotripters and Techniques for Controlling Cavitation

    Smith, Nathan Birchard

    In this dissertation work, the aim was to garner better mechanistic understanding of how shock wave lithotripsy (SWL) breaks stones in order to guide design improvements to modern electromagnetic (EM) shock wave lithotripters. To accomplish this goal, experimental studies were carefully designed to isolate mechanisms of fragmentation, and models for wave propagation, fragmentation, and stone motion were developed. In the initial study, a representative EM lithotripter was characterized and tested for in vitro stone comminution efficiency at a variety of field positions and doses using phantom kidney stones of variable physical properties, and in different fluid mediums to isolate the contribution of cavitation. Through parametric analysis of the acoustic field measurements alongside comminution results, a logarithmic correlation was determined between average peak pressure incident on the stone surface and comminution efficiency. It was also noted that for a given stone type, the correlations converged to an average peak pressure threshold for fragmentation, independent of fluid medium in use. The correlation of average peak pressure to efficacy supports the rationale for the acoustic lens modifications, which were pursued to simultaneously enhance beam width and optimize the pulse profile of the lithotripter shock wave (LSW) via in situ pulse superposition for improved stone fragmentation by stress waves and cavitation, respectively. In parallel, a numerical model for wave propagation was used to investigate the variations of critical parameters with changes in lens geometry. A consensus was reached on a new lens design based on high-speed imaging and stone comminution experiments against the original lens at a fixed acoustic energy setting. The results have demonstrated that the new lens has improved efficacy away from the focus, where stones may move due to respiration, fragmentation, acoustic radiation forces, or voluntary patient movements. Using the

  9. Anisotropic Metamaterials as sensing devices in acoustics and electromagnetism

    Sánchez-Dehesa Moreno-Cid, José; Torrent Martí, Daniel; Carbonell Olivares, Jorge

    2012-01-01

    We analyze the properties of acoustic and electromagnetic metamaterials with anisotropic constitutive parameters. Particularly, we analyze the so-called Radial Wave Crystals, which are radially periodic structures verifying the Bloch theorem. This type of crystals can be designed and implemented in acoustics as well as in electromagnetism by using anisotropic metamaterials. In acoustics, we have previously predicted that they can be employed as acoustic cavities with huge quality ...

  10. Dynamic acoustic tractor beams

    Mitri, F. G.

    2015-03-01

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  11. Dynamic acoustic tractor beams

    Mitri, F. G., E-mail: F.G.Mitri@ieee.org [Chevron, Area 52 Technology – ETC, Santa Fe, New Mexico 87508 (United States)

    2015-03-07

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  12. Intraocular camera for retinal prostheses: Refractive and diffractive lens systems

    Hauer, Michelle Christine

    The focus of this thesis is on the design and analysis of refractive, diffractive, and hybrid refractive/diffractive lens systems for a miniaturized camera that can be surgically implanted in the crystalline lens sac and is designed to work in conjunction with current and future generation retinal prostheses. The development of such an intraocular camera (IOC) would eliminate the need for an external head-mounted or eyeglass-mounted camera. Placing the camera inside the eye would allow subjects to use their natural eye movements for foveation (attention) instead of more cumbersome head tracking, would notably aid in personal navigation and mobility, and would also be significantly more psychologically appealing from the standpoint of personal appearances. The capability for accommodation with no moving parts or feedback control is incorporated by employing camera designs that exhibit nearly infinite depth of field. Such an ultracompact optical imaging system requires a unique combination of refractive and diffractive optical elements and relaxed system constraints derived from human psychophysics. This configuration necessitates an extremely compact, short focal-length lens system with an f-number close to unity. Initially, these constraints appear highly aggressive from an optical design perspective. However, after careful analysis of the unique imaging requirements of a camera intended to work in conjunction with the relatively low pixellation levels of a retinal microstimulator array, it becomes clear that such a design is not only feasible, but could possibly be implemented with a single lens system.

  13. Transformational acoustic metamaterials based on pressure gradients

    García-Meca, C; Barceló, C; Jannes, G; Sánchez-Dehesa, J; Martínez, A

    2014-01-01

    We apply a homogenization process to the acoustic velocity potential wave equation. The study of various examples shows that the resulting effective properties are different from those of the homogenized pressure wave equation for the same underlying acoustic parameters. A careful analysis reveals that a given set of inhomogeneous parameters represents an entirely different physical system depending on the considered equation. Our findings unveil a different way of tailoring acoustic properties through gradients of the static pressure. In contrast to standard metafluids based on isobaric composites, this alternative kind of metafluids is suitable for the implementation of transformational devices designed via the velocity potential equation. This includes acoustic systems in a moving background or arising from general space-time transformations. As an example, we design a device able to cloak the acoustic velocity potential.

  14. Liquid crystal adaptive lens with circular electrodes

    Sun, Yi

    The liquid crystal adaptive lens (LCAL) developed in this research is an electro-optical device using a set of electrodes to grade the refractive index across its aperture. Adjusting the applied voltages permits continuous control of focal length. The first effort at developing an LCAL using circular electrodes to provide a simpler architecture than previous devices using linear electrodes is presented in this dissertation. A theoretical study for an LCAL with circular electrodes is performed. The liquid crystal behavior and the applied voltage profile required for different focal lengths is discussed. Numerical simulation of the refractive index change and the Point Spread Function is developed to study the aberrations and predict performance with circular electrode geometry. A Fresnel lens phase profile is applied to yield a lens with a useful F-number, and a previously unexplored aberration is identified and characterized. An LCAL prototype was designed with a set of high-density electrodes in the conductive ladder meshing configuration, which results in a small number of externally controlled electrodes. A new electronic controller was designed and built with a fast response and accurate output to apply the voltage set to the LCAL. An electro-optical feedback control system based on LabVIEW software was developed to optimize control output voltages using signals from a CID camera. A prototype LCAL was designed with a 7.86 mm diameter aperture and a focal length adjustable from 0.2 m to infinity. It was fabricated on a glass substrate with two layers of transparent electrodes, insulating layers, and vias to connect the two conducting layers. The special fabrication challenges involved are discussed. Focusing experiments were performed by auto-dithering using the electro-optical feedback control system. The point spread function measurement results are presented, demonstrating that the focal spot size reaches the diffraction limit, but astigmatism created by the

  15. Planar immersion lens with metasurfaces

    Ho, John S; Tanabe, Yuji; Yeh, Alexander J; Fan, Shanhui; Poon, Ada S Y

    2015-01-01

    The solid immersion lens is a powerful optical tool that allows light entering material from air or vacuum to focus to a spot much smaller than the free-space wavelength. Conventionally, however, they rely on semispherical topographies and are non-planar and bulky, which limits their integration in many applications. Recently, there has been considerable interest in using planar structures, referred to as metasurfaces, to construct flat optical components for manipulating light in unusual ways. Here, we propose and demonstrate the concept of a planar immersion lens based on metasurfaces. The resulting planar device, when placed near an interface between air and dielectric material, can focus electromagnetic radiation incident from air to a spot in material smaller than the free-space wavelength. As an experimental demonstration, we fabricate an ultrathin and flexible microwave lens and further show that it achieves wireless energy transfer in material mimicking biological tissue.

  16. Development of a Laue lens for nuclear astrophysics

    The Laue lenses we study focuses in the domain of 0.1-1 MeV thanks to Bragg diffraction in the volume of a large number of small crystal tiles. The focal length of a typical Laue lens system is of the order of 100 m. This requirement calls for two formation flying satellites maintaining lens and detector at the focal distance. The major breakthrough of Laue lenses is to decouple collecting area from detector area. Concentrating a signal from the large area of a Laue lens onto a small focal spot dramatically increases the signal over background ratio with respect to present technologies. Here is the reason for the long awaited leap in sensitivity. The objective of the present thesis was to improve the concept, finding viable technical solutions towards a future space mission. Two aspects of the lens development have been highlighted in this thesis: the first one is an analytical model of the lens that is used to calculate and improve the performance of a certain configuration, the second aspect concerns the search and the characterization of diffracting media of interest. The lens model developed relies on a fast semi-analytical simulation library, permitting to build several design- and optimisation-tools. For the configuration of a given lens, this code computes the resulting effective area and point spread function in a handful of seconds. The model helps finding lens configurations (mass, pack ratio of the lens rings,...) which are automatically refined to match with effective area and energy coverage constraints. These tools have been used to investigate various design aspects, such as the influence of focal length, size, mosaic spread, structure and materials of crystals, etc... The central evaluation criterion in the model is a figure of merit, based on the compactness of the focal spot and the intensity of the collected signal. The second part of this work addresses the actual search and characterization of crystals potentially interesting for Laue lenses

  17. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    John l. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

    2003-07-01

    The 1st generation acoustic monitoring package was designed to detect and analyze weak acoustic signals inside natural gas transmission lines. Besides a microphone it housed a three-inch diameter aerodynamic acoustic signal amplifier to maximize sensitivity to leak induced {Delta}p type signals. The theory and test results of this aerodynamic signal amplifier was described in the master's degree thesis of our Research Assistant Deepak Mehra who is about to graduate. To house such a large three-inch diameter sensor required the use of a steel 300-psi rated 4 inch weld neck flange, which itself weighed already 29 pounds. The completed 1st generation Acoustic Monitoring Package weighed almost 100 pounds. This was too cumbersome to mount in the field, on an access port at a pipeline shut-off valve. Therefore a 2nd generation and truly Portable Acoustic Monitor was built. It incorporated a fully self-contained {Delta}p type signal sensor, rated for line pressures up to 1000 psi with a base weight of only 6 pounds. This is the Rosemont Inc. Model 3051CD-Range 0, software driven sensor, which is believed to have industries best total performance. Its most sensitive unit was purchased with a {Delta}p range from 0 to 3 inch water. This resulted in the herein described 2nd generation: Portable Acoustic Monitoring Package (PAMP) for pipelines up to 1000 psi. Its 32-pound total weight includes an 18-volt battery. Together with a 3 pound laptop with its 4-channel data acquisition card, completes the equipment needed for field acoustic monitoring of natural gas transmission pipelines.

  18. Tevatron electron lens and it's applications

    Zhang, X.L.; Shiltsev, V.; Valishev, A.; /Fermilab; Kamerdzhiev, V.; /Julich, Forschungszentrum; Romnov, A.; /Novosibirsk, IYF

    2009-08-01

    The Tevatron Electron Lens (TEL) is designed for the purpose of the Beam-beam tuneshift compensation. Now it's one of the vital parts of the Tevatron. In this report, its daily operations and beam study results are presented. And its possible future applications are also discussed as well.

  19. Acoustic Neurinomas

    Mohammad Faraji Rad

    2011-01-01

    Full Text Available Acoustic neuromas (AN are schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve also known as vestibular schwannoma(VS causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumor size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumor is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few. The predominant clinical endpoints of AN treatment include tumor control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL. It is uncertain if treating a small tumor leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment.   In this paper we review the literature for the natural course, the treatment alternatives and the results of AN. Finally, we present our experience with a management strategy applied for more than 30 years.

  20. Acoustic Spatiality

    Brandon LaBelle

    2012-06-01

    Full Text Available Experiences of listening can be appreciated as intensely relational, bringing us into contact with surrounding events, bodies and things. Given that sound propagates and expands outwardly, as a set of oscillations from a particular source, listening carries with it a sensual intensity, whereby auditory phenomena deliver intrusive and disruptive as well as soothing and assuring experiences. The physicality characteristic of sound suggests a deeply impressionistic, locational "knowledge structure" – that is, the ways in which listening affords processes of exchange, of being in the world, and from which we extend ourselves. Sound, as physical energy reflecting and absorbing into the materiality around us, and even one's self, provides a rich platform for understanding place and emplacement. Sound is always already a trace of location.Such features of auditory experience give suggestion for what I may call an acoustical paradigm – how sound sets in motion not only the material world but also the flows of the imagination, lending to forces of signification and social structure, and figuring us in relation to each other. The relationality of sound brings us into a steady web of interferences, each of which announces the promise or problematic of being somewhere.