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Sample records for sonar transmission beam

  1. Tongue-driven sonar beam steering by a lingual-echolocating fruit bat.

    Directory of Open Access Journals (Sweden)

    Wu-Jung Lee

    2017-12-01

    Full Text Available Animals enhance sensory acquisition from a specific direction by movements of head, ears, or eyes. As active sensing animals, echolocating bats also aim their directional sonar beam to selectively "illuminate" a confined volume of space, facilitating efficient information processing by reducing echo interference and clutter. Such sonar beam control is generally achieved by head movements or shape changes of the sound-emitting mouth or nose. However, lingual-echolocating Egyptian fruit bats, Rousettus aegyptiacus, which produce sound by clicking their tongue, can dramatically change beam direction at very short temporal intervals without visible morphological changes. The mechanism supporting this capability has remained a mystery. Here, we measured signals from free-flying Egyptian fruit bats and discovered a systematic angular sweep of beam focus across increasing frequency. This unusual signal structure has not been observed in other animals and cannot be explained by the conventional and widely-used "piston model" that describes the emission pattern of other bat species. Through modeling, we show that the observed beam features can be captured by an array of tongue-driven sound sources located along the side of the mouth, and that the sonar beam direction can be steered parsimoniously by inducing changes to the pattern of phase differences through moving tongue location. The effects are broadly similar to those found in a phased array-an engineering design widely found in human-made sonar systems that enables beam direction changes without changes in the physical transducer assembly. Our study reveals an intriguing parallel between biology and human engineering in solving problems in fundamentally similar ways.

  2. IDENTIFIKASI PROFIL DASAR LAUT MENGGUNAKAN INSTRUMEN SIDE SCAN SONAR DENGAN METODE BEAM PATTERN DISCRETE-EQUI-SPACED UNSHADED LINE ARRAY

    Directory of Open Access Journals (Sweden)

    Muhammad Zainuddin Lubis

    2017-05-01

    Full Text Available Laut Punggur merupakan laut yang terletak di Batam, Kepulauan Riau yang mempunyai beragam habitat objek,dan bentuk struktur bawah laut yang memiliki dinamika laut yang sangat tinggi. Side scan sonar (SSS merupakan instrumen pengembangan sistem sonar yang mampu menunjukkan dalam gambar dua dimensional permukaan dasar laut dengan kondisi kontur, topografi, dan target secara bersamaan. Metode Beam Pattern Discrete-Equi-Spaced Unshaded Line Array digunakan untuk menghitung beam pattern dua dimensi yang tergantung pada sudut dari gelombang suara yang masuk dari sumbu array yang diterima tergantung pada sudut di mana sinar suara pada array. Penelitian ini dilakukan pada Desember 2016 di laut Punggur,Batam, Kepulauan Riau-Indonesia, dengan koordinat 104 ° 08,7102 E dan 1° 03,2448 N sampai 1 ° 03.3977 N dan 104 ° 08,8133 E, menggunakan instrumen Side Scan Sonar C-Max CM2 Tow fish dengan frekuensi 325 kHz. Hasil yang diperoleh dari perekaman terdapat 7 target, dan Beam pattern dari metode Beam Discrete-Equi-Spaced Unshaded Line Array target 4 memiliki nilai tertinggi pada directivity Pattern yaitu 21.08 dB. Hasil model beam pattern ini memiliki nilai pusat pada incidence angle (o terhadap Directivity pattern (dB tidak berada di nilai 0 ataupun pada pusat beam pattern yang dihasilkan pada target 6 dengan nilai incident angle -1.5 o dan 1.5o mengalami penurunan hingga -40 dB. Karakteristik sedimen dasar perairan di laut punggur ditemukan lebih banyak pasir. Hasil metode Beam Discrete-Equi-Spaced Unshaded Line Array ditemukan bangkai kapal tenggelam.Kata Kunci: Side Scan Sonar, Beam Pattern Discrete-Equi-Spaced Unshaded Line Array, Incidence angle, Directivity pattern IDENTIFICATION OF SEABED PROFILE USING SIDE SCAN SONAR INSTRUMENT WITH PATTERN DISCRETE-EQUI-SPACED UNSHADED LINE ARRAY METHODRiau Islands is an island that has a variety of habitat objects, and forms of submarine structures that have a very high ocean dynamics, Punggur Sea is the sea

  3. Echolocating bats emit a highly directional sonar sound beam in the field

    DEFF Research Database (Denmark)

    Surlykke, Annemarie; Boel Pedersen, Simon; Jakobsen, Lasse

    2009-01-01

    Bats use echolocation or biosonar to navigate and find prey at night. They emit short ultrasonic calls and listen for reflected echoes. The beam width of the calls is central to the function of the sonar, but directionality of echolocation calls has never been measured from bats flying in the wild....... We used a microphone array to record sounds and determine horizontal directionality for echolocation calls of the trawling Daubenton's bat, Myotis daubentonii, flying over a pond in its natural habitat. Myotis daubentonii emitted highly directional calls in the field. Directionality increased...... and directionality can be explained by the simple piston model. The model also suggests that the increase in the emitted intensity in the field is caused by the increased directionality, focusing sound energy in the forward direction. The bat may increase directionality by opening the mouth wider to emit a louder...

  4. Asymmetric acoustic transmission in graded beam

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Li, E-mail: lj94172350@hotmail.com [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Wu, Jiu Hui, E-mail: ejhwu@mail.xjtu.edu.cn [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Guan, Dong; Lu, Kuan [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Gao, Nansha [School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Songhua, Cao [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

    2016-12-01

    We demonstrate the dynamic effective material parameters and vibration performance of a graded beam. The structure of the beam was composed of several unit cells with different fill factors. The dispersion relations and energy band structures of each unit cell were calculated using the finite element method (FEM). The dynamic effective material parameters in each unit cell of the graded beam were determined by the dispersion relations and energy band structures. Longitudinal wave propagation was investigated using a numerical method and FEM. The results show that the graded beam allows asymmetric acoustic transmission over a wide range of frequencies.

  5. Combining split-beam and dual-frequency identification sonars to estimate abundance of anadromous fishes in the Roanoke River, North Carolina

    Science.gov (United States)

    Hughes, Jacob B.; Hightower, Joseph E.

    2015-01-01

    Riverine hydroacoustic techniques are an effective method for evaluating abundance of upstream migrating anadromous fishes. To use these methods in the Roanoke River, North Carolina, at a wide site with uneven bottom topography, we used a combination of split-beam sonar and dual-frequency identification sonar (DIDSON) deployments. We aimed a split-beam sonar horizontally to monitor midchannel and near-bottom zones continuously over the 3-month spring monitoring periods in 2010 and 2011. The DIDSON was rotated between seven cross-channel locations (using a vertical aim) and nearshore regions (using horizontal aims). Vertical deployment addressed blind spots in split-beam coverage along the bottom and provided reliable information about the cross-channel and vertical distributions of upstream migrants. Using a Bayesian framework, we modeled sonar counts within four cross-channel strata and apportioned counts by species using species proportions from boat electrofishing and gill netting. Modeled estimates (95% credible intervals [CIs]) of total upstream migrants in 2010 and 2011 were 2.5 million (95% CI, 2.4–2.6 million) and 3.6 million (95% CI, 3.4–3.9 million), respectively. Results indicated that upstream migrants are extremely shore- and bottom-oriented, suggesting nearshore DIDSON monitoring improved the accuracy and precision of our estimates. This monitoring protocol and model may be widely applicable to river systems regardless of their cross-sectional width or profile.

  6. Cost-effective mapping of benthic habitats in inland reservoirs through split-beam sonar, indicator kriging, and historical geologic data.

    Directory of Open Access Journals (Sweden)

    Erik R Venteris

    Full Text Available Because bottom substrate composition is an important control on the temporal and spatial location of the aquatic community, accurate maps of benthic habitats of inland lakes and reservoirs provide valuable information to managers, recreational users, and scientists. Therefore, we collected vertical, split-beam sonar data (roughness [E1], hardness [E2], and bathymetry and sediment samples to make such maps. Statistical calibration between sonar parameters and sediment classes was problematic because the E1:E2 ratios for soft (muck and clay sediments overlapped a lower and narrower range for hard (gravel substrates. Thus, we used indicator kriging (IK to map the probability that unsampled locations did not contain coarse sediments. To overcome the calibration issue we tested proxies for the natural processes and anthropogenic history of the reservoir as potential predictive variables. Of these, a geologic map proved to be the most useful. The central alluvial valley and mudflats contained mainly muck and organic-rich clays. The surrounding glacial till and shale bedrock uplands contained mainly poorly sorted gravels. Anomalies in the sonar data suggested that the organic-rich sediments also contained trapped gases, presenting additional interpretive issues for the mapping. We extended the capability of inexpensive split-beam sonar units through the incorporation of historic geologic maps and other records as well as validation with dredge samples. Through the integration of information from multiple data sets, were able to objectively identify bottom substrate and provide reservoir users with an accurate map of available benthic habitat.

  7. Cost-Effective Mapping of Benthic Habitats in Inland Reservoirs through Split-Beam Sonar, Indicator Kriging, and Historical Geologic Data

    Energy Technology Data Exchange (ETDEWEB)

    Venteris, Erik R.; May, Cassandra

    2014-04-23

    Because bottom substrate composition is an important control on the temporal and spatial location of the aquatic community, accurate maps of benthic habitats of inland lakes and reservoirs provide valuable information to managers, recreational users, and scientists. Therefore, we collected vertical, split-beam sonar data (roughness [E1], hardness [E2], and bathymetry) and sediment samples to make such maps. Statistical calibration between sonar parameters and sediment classes was problematic because the E1:E2 ratios for soft (muck and clay) sediments overlapped a lower and narrower range for hard (gravel) substrates. Thus, we used indicator kriging (IK) to map the probability that unsampled locations did not contain coarse sediments. To overcome the calibration issue we tested proxies for the natural processes and anthropogenic history of the reservoir as potential predictive variables. Of these, a geologic map proved to be the most useful. The central alluvial valley and mudflats contained mainly muck and organic-rich clays. The surrounding glacial till and shale bedrock uplands contained mainly poorly sorted gravels. Anomalies in the sonar data suggested that the organic-rich sediments also contained trapped gases, presenting additional interpretive issues for the mapping. We extended the capability of inexpensive split-beam sonar units through the incorporation of historic geologic maps and other records as well as validation with dredge samples. Through the integration of information from multiple data sets, were able to objectively identify bottom substrate and provide reservoir users with an accurate map of available benthic habitat.

  8. Doppler-shifted neutral beam line shape and beam transmission

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Grisham, L.R.; Kokatnur, N.; Lagin, L.J.; Newman, R.A.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A.

    1994-04-01

    Analysis of Doppler-shifted Balmer-α line emission from the TFTR neutral beam injection systems has revealed that the line shape is well approximated by the sum of two Gaussians, or, alternatively, by a Lorentzian. For the sum of two Gaussians, the broad portion of the distribution contains 40% of the beam power and has a divergence five times that of the narrow part. Assuming a narrow 1/e- divergence of 1.3 degrees (based on fits to the beam shape on the calorimeter), the broad part has a divergence of 6.9 degrees. The entire line shape is also well approximated by a Lorentzian with a half-maximum divergence of 0.9 degrees. Up to now, fusion neutral beam modelers have assumed a single Gaussian velocity distribution, at the extraction plane, in each direction perpendicular to beam propagation. This predicts a beam transmission efficiency from the ion source to the calorimeter of 97%. Waterflow calorimetry data, however, yield a transmission efficiency of ∼75%, a value in rough agreement with predictions of the Gaussian or Lorentzian models presented here. The broad wing of the two Gaussian distribution also accurately predicts the loss in the neutralizer. An average angle of incidence for beam loss at the exit of the neutralizer is 2.2 degrees, rather than the 4.95 degrees subtended by the center of the ion source. This average angle of incidence, which is used in computing power densities on collimators, is shown to be a function of beam divergence

  9. Evaluation of a Single-Beam Sonar System to Map Seagrass at Two Sites in Northern Puget Sound, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Lacy, Jessica R.; Finlayson, David P.; Gelfenbaum, Guy

    2008-01-01

    Seagrass at two sites in northern Puget Sound, Possession Point and nearby Browns Bay, was mapped using both a single-beam sonar and underwater video camera. The acoustic and underwater video data were compared to evaluate the accuracy of acoustic estimates of seagrass cover. The accuracy of the acoustic method was calculated for three classifications of seagrass observed in underwater video: bare (no seagrass), patchy seagrass, and continuous seagrass. Acoustic and underwater video methods agreed in 92 percent and 74 percent of observations made in bare and continuous areas, respectively. However, in patchy seagrass, the agreement between acoustic and underwater video was poor (43 percent). The poor agreement between the two methods in areas with patchy seagrass is likely because the two instruments were not precisely colocated. The distribution of seagrass at the two sites differed both in overall percent vegetated and in the distribution of percent cover versus depth. On the basis of acoustic data, seagrass inhabited 0.29 km2 (19 percent of total area) at Possession Point and 0.043 km2 (5 percent of total area) at the Browns Bay study site. The depth distribution at the two sites was markedly different. Whereas the majority of seagrass at Possession Point occurred between -0.5 and -1.5 m MLLW, most seagrass at Browns Bay occurred at a greater depth, between -2.25 and -3.5 m MLLW. Further investigation of the anthropogenic and natural factors causing these differences in distribution is needed.

  10. Analysis of the Detectability of Sonar Under the Virtual Battlefield

    Directory of Open Access Journals (Sweden)

    Hou Chengyu

    2014-08-01

    Full Text Available Due to the high propagation speed and the low attenuation in the water, the sonar has played a crucial role in developing the ocean resources and the marine target detection. Therefore, simulation of the sonar detectability is indispensable to the virtual battlefield. This paper will combine the background noise model of the ocean, the reverberation model, the target strength model and the transmission loss to build the sonar performance model, and realize the calculation of the sonar detectability. Ultimately, the parameters’ effect in the sonar equation on the performance of the sonar detection is analyzed, and the validity of this model is verified by two serving sonars parameters.

  11. Oculina Banks Bathymetry 2002 from Multi-beam and Sidescan Sonar Surveys (NODC Accession 0090252)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are the result of a multi-beam echosounder survey conducted in the OHAPC by the M/V Liberty Star in October 2002. Two forms of data are available: 1)...

  12. Use of Multibeam and Dual-Beam Sonar Systems to Observe Cavitating Flow Produced by Ferryboats: In a Marine Renewable Energy Perspective

    Directory of Open Access Journals (Sweden)

    Francisco Francisco

    2017-07-01

    Full Text Available With the prospect to deploy hydrokinetic energy converters in areas with heavy boat traffic, a study was conducted to observe and assess the depth range of cavitating flow produced by ferryboats in narrow channels. This study was conducted in the vicinity of Finnhamn Island in Stockholm Archipelago. The objectives of the survey were to assess whether the sonar systems were able to observe and measure the depth of what can be cavitating flow (in a form of convected cloud cavitation produced by one specific type of ferryboats frequently operating in that route, as well as investigate if the cavitating flow within the wake would propagate deep enough to disturb the water column underneath the surface. A multibeam and a dual-beam sonar systems were used as measurement instruments. The hypothesis was that strong and deep wake can disturb the optimal operation of a hydrokinetic energy converter, therefore causing damages to its rotors and hydrofoils. The results showed that both sonar system could detect cavitating flows including its strength, part of the geometrical shape and propagation depth. Moreover, the boat with a propeller thruster produced cavitating flow with an intense core reaching 4 m of depth while lasting approximately 90 s. The ferry with waterjet thruster produced a less intense cavitating flow; the core reached depths of approximately 6 m, and lasted about 90 s. From this study, it was concluded that multibeam and dual-beam sonar systems with operating frequencies higher than 200 kHz were able to detect cavitating flows in real conditions, as long as they are properly deployed and the data properly analyzed.

  13. Transmission of high-power electron beams through small apertures

    International Nuclear Information System (INIS)

    Tschalär, C.; Alarcon, R.; Balascuta, S.; Benson, S.V.; Bertozzi, W.; Boyce, J.R.; Cowan, R.; Douglas, D.; Evtushenko, P.; Fisher, P.; Ihloff, E.; Kalantarians, N.; Kelleher, A.; Legg, R.; Milner, R.G.; Neil, G.R.; Ou, L.; Schmookler, B.; Tennant, C.; Williams, G.P.

    2013-01-01

    Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Beam transmission losses of 3 p.p.m. through a 2 mm diameter aperture were maintained during a 7 h continuous run

  14. Transmission of the Neutral Beam Heating Beams at TJ-II

    International Nuclear Information System (INIS)

    Fuentes Lopez, C.

    2007-01-01

    Neutral beam injection heating has been development for the TJ-II stellarator. The beam has a port-through power between 700-1500 kW and injection energy 40 keV. The sensibility of the injection system to the changes of several parameters is analysed. Beam transmission is limited by losses processes since beam is born into the ions source until is coming into the fusion machine. For the beam transmission optimization several beam diagnostics have been developed. A carbon fiber composite (CFC) target calorimeter has been installed at TJ-II to study in situ the power density distribution of the neutral beams. The thermographic print of the beam can be recorded and analysed in a reliable way due to the highly anisotropic thermal conductivity of the target material. With the combined thermographic and calorimetric measurements it has been possible to determine the power density distribution of the beam. It has been found that a large beam halo is present, which can be explained by the extreme misalignment of the grids. This kind of halo has a deleterious effect on beam transport and must be minimized in order to improve the plasma heating capability of the beams. (Author) 155 refs

  15. Phase space model for transmission of light beam

    International Nuclear Information System (INIS)

    Fu Shinian

    1989-01-01

    Based on Fermat's principle of ray optics, the Hamiltonian of an optical ray is derived by comparison with classical mechanics. A phase space model of light beam is proposed, assuming that the light beam, regarded as a group of rays, can be described by an ellipse in the μ-phase space. Therefore, the transmission of light beam is represented by the phase space matrix transformation. By means of this non-wave formulation, the same results are obtained as those from wave equation such as Kogelnik's ABCD law. As an example of the application on this model, the matching problem of optical cavity is solved

  16. Real-Time 3D Sonar Modeling And Visualization

    Science.gov (United States)

    1998-06-01

    looking back towards Manta sonar beam, Manta plus sonar from 1000m off track. 185 NUWC sponsor Erik Chaum Principal investigator Don Brutzman...USN Sonar Officer LT Kevin Byrne USN Intelligence Officer CPT Russell Storms USA Erik Chaum works in NUWC Code 22. He supervised the design and...McGhee, Bob, "The Phoenix Autonomous Underwater Vehicle," chapter 13, AI-BasedMobile Robots, editors David Kortenkamp, Pete Bonasso and Robin Murphy

  17. Ultrasound beam transmission using a discretely orthogonal Gaussian aperture basis

    Science.gov (United States)

    Roberts, R. A.

    2018-04-01

    Work is reported on development of a computational model for ultrasound beam transmission at an arbitrary geometry transmission interface for generally anisotropic materials. The work addresses problems encountered when the fundamental assumptions of ray theory do not hold, thereby introducing errors into ray-theory-based transmission models. Specifically, problems occur when the asymptotic integral analysis underlying ray theory encounters multiple stationary phase points in close proximity, due to focusing caused by concavity on either the entry surface or a material slowness surface. The approach presented here projects integrands over both the transducer aperture and the entry surface beam footprint onto a Gaussian-derived basis set, thereby distributing the integral over a summation of second-order phase integrals which are amenable to single stationary phase point analysis. Significantly, convergence is assured provided a sufficiently fine distribution of basis functions is used.

  18. Review: Marine Seismic And Side-Scan Sonar Investigations For Seabed Identification With Sonar System

    Directory of Open Access Journals (Sweden)

    Muhammad Zainuddin Lubis

    2017-06-01

    Full Text Available Marine seismic reflection data have been collected for decades and since the mid-to late- 1980s much of this data is positioned relatively accurately. Marine geophysical acquisition of data is a very expensive process with the rates regularly ship through dozens of thousands of euros per day. Acquisition of seismic profiles has the position is determined by a DGPS system and navigation is performed by Hypack and Maxview software that also gives all the offsets for the equipment employed in the survey. Examples of some projects will be described in terms of the project goals and the geophysical equipment selected for each survey and specific geophysical systems according to with the scope of work. For amplitude side scan sonar image, and in the multi-frequency system, color, becoming a significant properties of the sea floor, the effect of which is a bully needs to be fixed. The main confounding effect is due to absorption of water; geometric spread; shape beam sonar function (combined transmit-receive sonar beam intensity as a function of tilt angle obtained in this sonar reference frame; sonar vehicle roll; form and function of the seabed backscatter (proportion incident on the seabed backscattered signal to sonar as a function of the angle of incidence relative to the sea floor; and the slope of the seabed. The different angles of view are generated by the translation of the sonar, because of the discrete steps involved by the sequential pings, the angular sampling of the bottom.

  19. Principles of Sonar Performance Modeling

    NARCIS (Netherlands)

    Ainslie, M.A.

    2010-01-01

    Sonar performance modelling (SPM) is concerned with the prediction of quantitative measures of sonar performance, such as probability of detection. It is a multidisciplinary subject, requiring knowledge and expertise in the disparate fields of underwater acoustics, acoustical oceanography, sonar

  20. Optimization of Beam Transmission of PAL-PNF Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kim, S. K.; Kim, E. A. [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2012-05-15

    The PNF (Pohang Neutron Facility) electron Linac is providing converted neutrons and photons from electron beams to users for nuclear physics experiments and high energy gamma-ray exposures. This linac is capable of producing 100 MeV electron beams with a beam current of pulsed 100 mA. The pulse length is 2 {mu}s and the pulse repetition rate is typically 30 Hz. This linac consists of two SLAC-type S-band accelerating columns and the thermionic RF gun. They are powered by one klystron and the matching pulse modulator. The electron beams emitted from the RF gun are bunched as they pass through the alpha magnet and are injected into the accelerating column thereafter. In this paper, we discuss procedures and results of the beam transmission optimization with technical details of the accelerator system. We also briefly discuss the future upgrade plan to obtain short-pulse or electron beams for neutron TOF experiments by adopting a triode type thermionic DC electron gun

  1. Undergraduates Conducting Research Using High-Resolution Multibeam and Sidescan Sonar to Map and Characterize the Seabed: the BEAMS Program

    Science.gov (United States)

    Harris, M. S.; Sautter, L.

    2017-12-01

    The College of Charleston's BEnthic Acoustic Mapping and Survey (BEAMS) Program has just completed its 10th year of operation, and has proven to be remarkably effective at activating and maintaining undergraduate student interest in conducting research using sophisticated software, state-of-the-art instrumentation, enormous datasets, and significant experiential time. BEAMS students conduct research as part of a minimum 3-course sequence of marine geology-based content, marine geospatial software, and seafloor research courses. Over 140 students have completed the program, 56% of the graduated students remain active in the marine geospatial workforce or academic arenas. Forty-eight percent (48%) of those students are female. As undergraduates, students not only conduct independent research projects, but present their work at national conferences each year. Additionally, over 90 % of all "BEAMers" have been provided a 2-3 day at-sea experience on a dedicated BEAMS Program multibeam survey research cruise, and many students also volunteer as survey technicians aboard NOAA research vessels. Critical partnerships have developed with private industry to provide numerous collaborative opportunities and an employment/employer pipeline, as well as provision of software and hardware at many fiscal levels. Ongoing collaboration with the Marine Institute of Ireland and the National and Kapodistrian University of Athens has also provided valuable field opportunities and collaborative experiences. This talk will summarize the program while highlighting some of the key areas and topics investigated by students, including detailed geomorphologic studies of continental margins, submarine canyons, tectonic features and seamounts. Students also work with NOAA investigators to aid in the characterization of fish and deep coral habitats, and with BOEM researchers to study offshore windfield suitability and submerged cultural landscapes. Our sister program at the University of

  2. Analytically derived weighting factors for transmission tomography cone beam projections

    International Nuclear Information System (INIS)

    Yao Weiguang; Leszczynski, Konrad

    2009-01-01

    Weighting factors, which define the contributions of individual voxels of a 3D object to individual projection elements (pixels) on the detector, are the basic elements required in iterative tomographic reconstructions from transmission projections. Exact or as accurate as possible values for weighting factors are required in high-resolution reconstructions. Geometric complexity of the problem, however, makes it difficult to obtain exact weighting factor values. In this work, we derive an analytical expression for the weighting factors in cone beam projection geometry. The resulting formula is validated and applied to reconstruction from mega and kilovoltage x-ray cone beam projections. The reconstruction speed and accuracy are significantly improved by using the weighting factor values.

  3. Sonar Tank Area

    Data.gov (United States)

    Federal Laboratory Consortium — The Sonar Tank Facility permits low cost initial 'wet' testing and check out prior to full scale deployment at sea. It can manage controlled conditions calibration...

  4. Giga-bit optical data transmission module for Beam Instrumentation

    CERN Document Server

    Roedne, L T; Cenkeramaddi, L R; Jiao, L

    Particle accelerators require electronic instrumentation for diagnostic, assessment and monitoring during operation of the transferring and circulating beams. A sensor located near the beam provides an electrical signal related to the observable quantity of interest. The front-end electronics provides analog-to-digital conversion of the quantity being observed and the generated data are to be transferred to the external digital back-end for data processing, and to display to the operators and logging. This research project investigates the feasibility of radiation-tolerant giga-bit data transmission over optic fibre for beam instrumentation applications, starting from the assessment of the state of the art technology, identification of challenges and proposal of a system level solution, which should be validated with a PCB design in an experimental setup. Radiation tolerance of 10 kGy (Si) Total Ionizing Dose (TID) over 10 years of operation, Bit Error Rate (BER) 10-6 or better. The findings and results of th...

  5. NMFS Water Column Sonar Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water column sonar data are an important component of fishery independent surveys, habitat studies and other research. NMFS water column sonar data are archived here.

  6. FPGA-Based Sonar Processing

    National Research Council Canada - National Science Library

    Graham, Paul; Nelson, Brent

    1998-01-01

    This paper presents the application of time-delay sonar beamforming and discusses a multi-board FPGA system for performing several variations of this beamforming method in real-time for realistic sonar arrays...

  7. Transmission property and its applications of MeV ion beams with various capillaries

    International Nuclear Information System (INIS)

    Fujita, N; Ishii, K; Ogawa, H

    2012-01-01

    In order to clarify transmission properties of an ion beam extracted with various capillaries into the air, we have measured intensity distributions for the core and the halo components of MeV ion beams using various capillaries. In addition, we have performed in-air-RBS and in-air-PIXE from the point of the application. At the conference, progress report of transmission properties of ion beams with various capillaries and its applications will be presented.

  8. The Experimental Verification of Gaussian Beam Coupling for ECH Transmission Line at 400 GHz

    Directory of Open Access Journals (Sweden)

    Choe Mun Seok

    2017-01-01

    Full Text Available We design a quasi-optical transmission line system for a 400 GHz gyrotron beam. The 400GHz Gaussian beam is injected to a corrugated waveguide bounced from a quasi-optical mirror. From detailed 2D field patterns of the output beam emitted from the corrugated waveguide, we analyze the mode contents and the source of non-ideal beam expansion

  9. Beam transmission efficiency between injector and target in the GANIL complex

    International Nuclear Information System (INIS)

    Beck, R.; Bru, B.; Ricaud, C.

    1984-06-01

    In order to achieve a maximum transmission efficiency, efforts have been made in three directions: beam measurements, understanding of the physical phenomenon, tuning method. The characteristics of the beam extracted from the three cyclotrons have been measured. The ensuing optical effects are analysed. The tuning of the transport-lines, depending on the characteristics of the extracted beams and the required beam properties on the target, is described

  10. Reflection and Transmission of a Focused Finite Amplitude Sound Beam Incident on a Curved Interface

    Science.gov (United States)

    Makin, Inder Raj Singh

    Reflection and transmission of a finite amplitude focused sound beam at a weakly curved interface separating two fluid-like media are investigated. The KZK parabolic wave equation, which accounts for thermoviscous absorption, diffraction, and nonlinearity, is used to describe the high intensity focused beam. The first part of the work deals with the quasilinear analysis of a weakly nonlinear beam after its reflection and transmission from a curved interface. A Green's function approach is used to define the field integrals describing the primary and the nonlinearly generated second harmonic beam. Closed-form solutions are obtained for the primary and second harmonic beams when a Gaussian amplitude distribution at the source is assumed. The second part of the research uses a numerical frequency domain solution of the KZK equation for a fully nonlinear analysis of the reflected and transmitted fields. Both piston and Gaussian sources are considered. Harmonic components generated in the medium due to propagation of the focused beam are evaluated, and formation of shocks in the reflected and transmitted beams is investigated. A finite amplitude focused beam is observed to be modified due to reflection and transmission from a curved interface in a manner distinct from that in the case of a small signal beam. Propagation curves, beam patterns, phase plots and time waveforms for various parameters defining the source and media pairs are presented, highlighting the effect of the interface curvature on the reflected and transmitted beams. Relevance of the current work to biomedical applications of ultrasound is discussed.

  11. Manipulation and analysis of atomic and molecular beams using transmission gratings and Fresnel zone plates

    Energy Technology Data Exchange (ETDEWEB)

    Grisenti, R.E.

    2000-06-01

    In this thesis experimental results on the diffraction of rare gas atoms (He, Ne, Ar, Kr) and molecular (D{sub 2}) beams by a 100 nm period transmission grating and on the focusing of a helium atom beam through a Fresnel zone plate have been reported. (orig.)

  12. The transmission of finite amplitude sound beam in multi-layered biological media

    Science.gov (United States)

    Liu, Xiaozhou; Li, Junlun; Yin, Chang; Gong, Xiufen; Zhang, Dong; Xue, Honghui

    2007-02-01

    Based on the Khokhlov Zabolotskaya Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media.

  13. The transmission of finite amplitude sound beam in multi-layered biological media

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaozhou [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)]. E-mail: xzliu@nju.edu.cn; Li, Junlun [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Yin, Chang [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Gong, Xiufen [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Zhang, Dong [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Xue, Honghui [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)

    2007-02-19

    Based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media.

  14. The transmission of finite amplitude sound beam in multi-layered biological media

    International Nuclear Information System (INIS)

    Liu, Xiaozhou; Li, Junlun; Yin, Chang; Gong, Xiufen; Zhang, Dong; Xue, Honghui

    2007-01-01

    Based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media

  15. Characteristic analysis of coupled transmission lines in stripline-type beam position monitor

    International Nuclear Information System (INIS)

    Suwada, T.

    2013-01-01

    Signal transmission characteristics in stripline electrodes of a stripline-type beam position monitor (BPM) are discussed on the basis of a coupled-mode analysis in electromagnetically coupled transmission lines. The physical prospect in the calibration procedure of stripline electrodes is improved in terms of signal transmission characteristics in the frequency domain. It is demonstrated that in the signal transmission with electromagnetic coupling between the stripline electrodes, the magnetic- and electric-coupling parameters play an important role depending upon the spatial configuration and mechanical structure of the stripline electrodes. In this report, a theoretical analysis, and experimental investigation into signal transmission characteristics and performance in a standard stripline-type BPM are described in detail on the basis of a coupled-mode analysis in uniform transmission lines

  16. Multiresolution 3-D reconstruction from side-scan sonar images.

    Science.gov (United States)

    Coiras, Enrique; Petillot, Yvan; Lane, David M

    2007-02-01

    In this paper, a new method for the estimation of seabed elevation maps from side-scan sonar images is presented. The side-scan image formation process is represented by a Lambertian diffuse model, which is then inverted by a multiresolution optimization procedure inspired by expectation-maximization to account for the characteristics of the imaged seafloor region. On convergence of the model, approximations for seabed reflectivity, side-scan beam pattern, and seabed altitude are obtained. The performance of the system is evaluated against a real structure of known dimensions. Reconstruction results for images acquired by different sonar sensors are presented. Applications to augmented reality for the simulation of targets in sonar imagery are also discussed.

  17. Water Column Sonar Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  18. The echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis).

    Science.gov (United States)

    Fang, Liang; Wu, Yuping; Wang, Kexiong; Pine, Matthew K; Wang, Ding; Li, Songhai

    2017-08-01

    While the transmission beam of odontocetes has been described in a number of studies, the majority of them that have measured the transmission beam in two dimensions were focused on captive animals. Within the current study, a dedicated cross hydrophone array with nine elements was used to investigate the echolocation transmission beam of free-ranging Indo-Pacific humpback dolphins. A total of 265 on-axis clicks were analyzed, from which the apparent peak to peak source levels ranged between 168 to 207 dB (mean 184.5 dB ± 6.6 dB). The 3-dB beam width along the horizontal and vertical plane was 9.6° and 7.4°, respectively. Measured separately, the directivity index of the horizontal and vertical plane was 12.6 and 13.5 dB, respectively, and the overall directivity index (both planes combined) was 29.5 dB. The beam shape was slightly asymmetrical along the horizontal and vertical axis. Compared to other species, the characteristics of the transmitting beam of Indo-Pacific humpback dolphins were relatively close to the bottlenose dolphin (Tursiops truncatus), likely due to the similarity in the peak frequency and waveform of echolocation clicks and comparable body sizes of the two species.

  19. Preparation of transmission electron microscopy cross-section specimens using focused ion beam milling

    International Nuclear Information System (INIS)

    Langford, R.M.; Petford-Long, A.K.

    2001-01-01

    The preparation of transmission electron microscopy cross-section specimens using focused ion beam milling is outlined. The 'liftout' and 'trench' techniques are both described in detail, and their relative advantages and disadvantages are discussed. Artifacts such as ion damage to the top surface and sidewalls of the cross-section specimens, and methods of reducing them, are addressed

  20. The Development of a Hibachi Window for Electron Beam Transmission in a KrF Laser

    International Nuclear Information System (INIS)

    Gentile, C.A.; Parsells, R.; Butler, J.E.; Sethian, J.D.; Ciebiera, L.; Hegeler, F.; Jun, C.; Langish, S.; Myers, M.

    2003-01-01

    In support of Inertial Fusion Energy (IFE), a 150 (micro)m thick silicon (Si) wafer coated on one side with a 1.2 (micro)m nanocrystalline diamond foil is being fabricated as an electron beam transmission (hibachi) window for use in KrF lasers. The hibachi window separates the lasing medium from the electron beam source while allowing the electron beam to pass through. The hibachi window must be capable of withstanding the challenging environment presented in the lasing chamber, which include: fluorine gas, delta pressure >2 atm at 5 Hz, and a high heat flux due to the transmission of electrons passing through the foil. Tests at NRL/Electra and at PPPL have shown that a device employing these novel components in the stated configuration provide for a robust hibachi window with structural integrity

  1. Magnet Lattice Design for the Transmission of Power Using Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Marley, Daniel; /North Carolina State U. /SLAC

    2012-08-24

    As the amount of electricity generated by renewable energy sources continues to increase, the current method of power transmission will not serve as an adequate method for transmitting power over very long distances. A new method for transmitting power is proposed using particle beams in a storage ring. Particle beams offer an incredibly energy efficient alternative to transmission lines in transmitting power over very long distances. A thorough investigation of the magnet lattice design for this storage ring is presented. The design demonstrates the ability to design a ring with stable orbits over a 381.733 km circumference. Double bend achromats and FODO cells are implemented to achieve appropriate {beta} functions and dispersion functions for 9-11 GeV electron beams.

  2. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-11-01

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

  3. Magnetically insulated transmission line used for relativistic electron beam injection into SPAC-VI

    International Nuclear Information System (INIS)

    Tsuzuki, Tetsuya; Narihara, Kazumichi; Tomita, Yukihiro; Mohri, Akihiro.

    1980-10-01

    For the purpose to inject the electron beam with energy of about 1.5 MeV and current of about 100 kA into the SPAC-6 (torus device), a magnetically insulated transmission line was designed and constructed. The motion of electrons in the line was theoretically analyzed. The requirements for the design of the transmission line were as follows-: (a) condition of magnetic insulation, (b) suppression against reverse gas flow from the beam source to the torus, (c) care to minimize the influence of strong torus magnetic field, (d) reduction of inductance and (e) safety engineering measures, e.g., separation valve in the MITL between the beam source and the SPAC-6. The transmission line of 2.4 m long was designed and constructed. The wave forms of electric potential and current were measured. The transmission efficiency of current along the axis and the efficiency as a function of current at the end of the line were also measured. The reason of the loss of current is discussed. (J.P.N.)

  4. Sidescan Sonar Image Matching Using Cross Correlation

    DEFF Research Database (Denmark)

    Thisen, Erik; Sørensen, Helge Bjarup Dissing; Stage, Bjarne

    2003-01-01

    When surveying an area for sea mines with a sidescan sonar, the ability to find the same object in two different sonar images is helpful to determine the nature of the object. The main problem with matching two sidescan sonar images is that a scene changes appearance when viewed from different vi...

  5. Magneto-optical transmission-reflection beam splitter for multi-level atoms

    International Nuclear Information System (INIS)

    Murphy, J.E.; Goodman, P.; Sidorov, A.I.

    1994-01-01

    An atomic de Broglie wave beam splitter is proposed. The interaction of multi-level atoms (J g = 1 - J e = 0) with a laser beam in the presence of a static magnetic field leads to the partial transmission and reflection of the atomic beam. The coherent splitting of the atomic beam occurs due to non-adiabatic transitions between different dressed states in the vicinity of avoided crossings. The transition probabilities and populations of split beams are dependent on the value of the magnetic field, laser detuning, and the ratio between different polarization components in the laser beam. For optimal conditions the population of each of the two transmitted and two reflected beams is 25 per cent. For cooled atoms it is possible to obtain splitting angles of 80 mrad. The effect of spontaneous emission during the atom-light interaction was estimated and for a reasonable detuning losses were reduced to less than 10 per cent. 14 refs., 1 tab., 6 figs

  6. Analysis method of beam pointing stability based on optical transmission matrix

    Science.gov (United States)

    Wang, Chuanchuan; Huang, PingXian; Li, Xiaotong; Cen, Zhaofen

    2016-10-01

    Quite a lot of factors will make effects on beam pointing stability of an optical system, Among them, the element tolerance is one of the most important and common factors. In some large laser systems, it will make final micro beams spot on the image plane deviate obviously. So it is essential for us to achieve effective and accurate analysis theoretically on element tolerance. In order to make the analysis of beam pointing stability convenient and theoretical, we consider transmission of a single chief ray rather than beams approximately to stand for the whole spot deviation. According to optical matrix, we also simplify this complex process of light transmission to multiplication of many matrices. So that we can set up element tolerance model, namely having mathematical expression to illustrate spot deviation in an optical system with element tolerance. In this way, we can realize quantitative analysis of beam pointing stability theoretically. In second half of the paper, we design an experiment to get the spot deviation in a multipass optical system caused by element tolerance, then we adjust the tolerance step by step and compare the results with the datum got from tolerance model, finally prove the correction of tolerance model successfully.

  7. Transmission line analysis of beam deflection in a BPM stripline kicker

    International Nuclear Information System (INIS)

    Caporaso, G.J.; Chen, Yu Ju; Poole, B.

    1997-05-01

    In the usual treatment of impedances of beamline structures the electromagnetic response is computed under the assumption that the source charge trajectory is parallel to the propagation axis and is unaffected by the wake of the structure. For high energy beams of relatively low current this is generally a valid assumption. Under certain conditions the assumption of a parallel source charge trajectory is no longer valid and the effects of the changing trajectory must be included in the analysis. Here the usual transmission line analysis that has been applied to BPM type transverse kickers is extended to include the self-consistent motion of the beam in the structure

  8. Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator

    International Nuclear Information System (INIS)

    Ge, Yong; Liu, Shu-sen; Yuan, Shou-qi; Xia, Jian-ping; Guan, Yi-jun; Sun, Hong-xiang; Zhang, Shu-yi

    2016-01-01

    We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications.

  9. Chemical Reactions of Molecules Promoted and Simultaneously Imaged by the Electron Beam in Transmission Electron Microscopy.

    Science.gov (United States)

    Skowron, Stephen T; Chamberlain, Thomas W; Biskupek, Johannes; Kaiser, Ute; Besley, Elena; Khlobystov, Andrei N

    2017-08-15

    The main objective of this Account is to assess the challenges of transmission electron microscopy (TEM) of molecules, based on over 15 years of our work in this field, and to outline the opportunities in studying chemical reactions under the electron beam (e-beam). During TEM imaging of an individual molecule adsorbed on an atomically thin substrate, such as graphene or a carbon nanotube, the e-beam transfers kinetic energy to atoms of the molecule, displacing them from equilibrium positions. Impact of the e-beam triggers bond dissociation and various chemical reactions which can be imaged concurrently with their activation by the e-beam and can be presented as stop-frame movies. This experimental approach, which we term ChemTEM, harnesses energy transferred from the e-beam to the molecule via direct interactions with the atomic nuclei, enabling accurate predictions of bond dissociation events and control of the type and rate of chemical reactions. Elemental composition and structure of the reactant molecules as well as the operating conditions of TEM (particularly the energy of the e-beam) determine the product formed in ChemTEM processes, while the e-beam dose rate controls the reaction rate. Because the e-beam of TEM acts simultaneously as a source of energy for the reaction and as an imaging tool monitoring the same reaction, ChemTEM reveals atomic-level chemical information, such as pathways of reactions imaged for individual molecules, step-by-step and in real time; structures of illusive reaction intermediates; and direct comparison of catalytic activity of different transition metals filmed with atomic resolution. Chemical transformations in ChemTEM often lead to previously unforeseen products, demonstrating the potential of this method to become not only an analytical tool for studying reactions, but also a powerful instrument for discovery of materials that can be synthesized on preparative scale.

  10. Reliability of fish size estimates obtained from multibeam imaging sonar

    Science.gov (United States)

    Hightower, Joseph E.; Magowan, Kevin J.; Brown, Lori M.; Fox, Dewayne A.

    2013-01-01

    Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret, and they contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a dual-frequency identification sonar (DIDSON) multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, striped bass Morone saxatilis, white perch M. americana, and channel catfish Ictalurus punctatus of known size (20–141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate – total length)/total length × 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon (x̄  =  −8.34, SE  =  2.39) and white perch (x̄  = 14.48, SE  =  3.99) but not striped bass (x̄  =  3.71, SE  =  2.58) or channel catfish (x̄  = 3.97, SE  =  5.16). Underestimating lengths of Atlantic sturgeon may be due to difficulty in detecting the snout or the longer dorsal lobe of the heterocercal tail. White perch was the smallest species tested, and it had the largest percent measurement errors (both positive and negative) and the lowest percentage of images classified as good or acceptable. Automated length estimates for the four species using Echoview software varied with position in the view-field. Estimates tended to be low at more extreme azimuthal angles (fish's angle off-axis within the view-field), but mean and maximum estimates were highly correlated with total length. Software estimates also were biased by fish images partially outside the view-field and when acoustic crosstalk occurred (when a fish perpendicular to the sonar and at relatively close range is detected in the side lobes of adjacent beams). These sources of

  11. Transmission of the Neutral Beam Heating Beams at TJ-II; Transmision del Haz de Neutros de Calentamiento en TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes Lopez, C

    2007-09-27

    Neutral beam injection heating has been development for the TJ-II stellarator. The beam has a port-through power between 700-1500 kW and injection energy 40 keV. The sensibility of the injection system to the changes of several parameters is analysed. Beam transmission is limited by losses processes since beam is born into the ions source until is coming into the fusion machine. For the beam transmission optimization several beam diagnostics have been developed. A carbon fiber composite (CFC) target calorimeter has been installed at TJ-II to study in situ the power density distribution of the neutral beams. The thermographic print of the beam can be recorded and analysed in a reliable way due to the highly anisotropic thermal conductivity of the target material. With the combined thermographic and calorimetric measurements it has been possible to determine the power density distribution of the beam. It has been found that a large beam halo is present, which can be explained by the extreme misalignment of the grids. This kind of halo has a deleterious effect on beam transport and must be minimized in order to improve the plasma heating capability of the beams. (Author) 155 refs.

  12. Multibeam sonar backscatter data processing

    Science.gov (United States)

    Schimel, Alexandre C. G.; Beaudoin, Jonathan; Parnum, Iain M.; Le Bas, Tim; Schmidt, Val; Keith, Gordon; Ierodiaconou, Daniel

    2018-06-01

    Multibeam sonar systems now routinely record seafloor backscatter data, which are processed into backscatter mosaics and angular responses, both of which can assist in identifying seafloor types and morphology. Those data products are obtained from the multibeam sonar raw data files through a sequence of data processing stages that follows a basic plan, but the implementation of which varies greatly between sonar systems and software. In this article, we provide a comprehensive review of this backscatter data processing chain, with a focus on the variability in the possible implementation of each processing stage. Our objective for undertaking this task is twofold: (1) to provide an overview of backscatter data processing for the consideration of the general user and (2) to provide suggestions to multibeam sonar manufacturers, software providers and the operators of these systems and software for eventually reducing the lack of control, uncertainty and variability associated with current data processing implementations and the resulting backscatter data products. One such suggestion is the adoption of a nomenclature for increasingly refined levels of processing, akin to the nomenclature adopted for satellite remote-sensing data deliverables.

  13. Cleaning Massive Sonar Point Clouds

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Larsen, Kasper Green; Mølhave, Thomas

    2010-01-01

    We consider the problem of automatically cleaning massive sonar data point clouds, that is, the problem of automatically removing noisy points that for example appear as a result of scans of (shoals of) fish, multiple reflections, scanner self-reflections, refraction in gas bubbles, and so on. We...

  14. Power electron beam front shortening in magnetically insulated transmission line with inner coaxial dielectric insert

    International Nuclear Information System (INIS)

    Galstjan, E.A.; Kazanskiy, L.N.

    1995-01-01

    By now the technology of high-power high-current relativistic electron beams with microsecond duration has been developed. The same technology is used in high-power electric pulse generation. However at present the high-power beams of subnanosecond duration are necessary for some investigations and applications. The maximum power parameter achieved by means of the usual technology is limited by a value in the range of 100-300 MW. For this reason a search for new ways to generate high-power REB (relativistic electron beam) is a topical problem. It is obvious that this problem may be reduced to the generation of pulses with a subnanosecond front duration. There are many methods to shorten a pulse duration to its front duration for instance, by using parts of short-circuited transmission lines

  15. Simulation calculation for the energy deposition profile and the transmission fraction of intense pulsed electron beam at various incident angles

    International Nuclear Information System (INIS)

    Yang Hailiang; Qiu Aici; Zhang Jiasheng; Huang Jianjun; Sun Jianfeng

    2002-01-01

    The incident angles have a heavy effect on the intense pulsed electron beam energy deposition profile, energy deposition fraction and beam current transmission fraction in material. The author presents electron beam energy deposition profile and energy deposition fraction versus electron energy (0.5-2.0 MeV), at various incident angles for three aluminum targets of various thickness via theoretical calculation. The intense pulsed electron beam current transmission fractions versus electron energy (0.4-1.4 MeV) at various incident angles for three thickness of carbon targets were also theoretically calculated. The calculation results indicate that the deposition energy in unit mass of material surface layer increase with the rise of electron beam incident angle, and electron beam with low incident angle (closer to normal incident angle) penetrates deeper into the target material. The electron beams deposit more energy in unit mass of material surface layer at 60 degree-70 degree incident angle

  16. Truncation artifact suppression in cone-beam radionuclide transmission CT using maximum likelihood techniques: evaluation with human subjects

    International Nuclear Information System (INIS)

    Manglos, S.H.

    1992-01-01

    Transverse image truncation can be a serious problem for human imaging using cone-beam transmission CT (CB-CT) implemented on a conventional rotating gamma camera. This paper presents a reconstruction method to reduce or eliminate the artifacts resulting from the truncation. The method uses a previously published transmission maximum likelihood EM algorithm, adapted to the cone-beam geometry. The reconstruction method is evaluated qualitatively using three human subjects of various dimensions and various degrees of truncation. (author)

  17. On the modification to the SNS extracted proton beam to allow for a transmission target

    International Nuclear Information System (INIS)

    Reading, D.H.

    1979-07-01

    The present SNS proton beam line consists of a series of triplets of quadrupoles with an achromatic bend such that the protons are taken from the accelerator ring into Hall 3, down its centre line onto the target. The modification described here has been prompted by the demands of a proposed negative pion bio-medical beam line, and the adaption replaces the last three triplets QT12, QT13 and QT14 (Quadrupoles Q41 to Q49 incl.). It begins at an achromatic waist in the original design, and by the use of three triplets of greater aperture produces a further small waist for a target station before focussing the 'object' produced by this transmission target onto the SNS target. (UK)

  18. A comparative study for different shielding material composition and beam geometry applied to PET facilities: simulated transmission curves

    OpenAIRE

    Hoff, Gabriela; Costa, Paulo Roberto

    2013-01-01

    The aim of this work is to simulate transmission data for different beam geometry and material composition in order to evaluate the effect of these parameters on transmission curves. The simulations are focused on outgoing spectra for shielding barriers used in PET facilities. The behavior of the transmission was evaluated as a function of the shielding material composition and thickness using Geant4 Monte Carlo code, version 9.2 p 03.The application was benchmarked for barited mortar and com...

  19. Post-ion beam induced degradation of copper layers in transmission electron microscopy specimens

    Science.gov (United States)

    Seidel, F.; Richard, O.; Bender, H.; Vandervorst, W.

    2015-11-01

    Copper containing transmission electron microscopy (TEM) specimens frequently show corrosion after focused ion beam (FIB) preparation. This paper reveals that the corrosion product is a Cu-S phase growing over the specimen surface. The layer is identified by energy-dispersive x-ray spectroscopy, and lattice spacing indexing of power spectra patterns. The corrosion process is further studied by TEM on cone-shaped specimens, which are intentionally stored after FIB preparation with S flakes for short time. Furthermore, a protective method against corrosion is developed by varying the time in the FIB vacuum and the duration of a subsequent plasma cleaning.

  20. NPS ARIES Forward Look Sonar Integration

    National Research Council Canada - National Science Library

    Healey, A. J; Horner, D. P

    2004-01-01

    This work integrated an experimental Blazed Array Forward Looking Sonar (FLS) developed by the University of Washington, Applied Physics Laboratories into the ARIES autonomous underwater vehicle (AUV...

  1. High-efficiency dual-modes vortex beam generator with polarization-dependent transmission and reflection properties.

    Science.gov (United States)

    Tang, Shiwei; Cai, Tong; Wang, Guang-Ming; Liang, Jian-Gang; Li, Xike; Yu, Jiancheng

    2018-04-23

    Vortex beam is believed to be an effective way to extend communication capacity, but available efforts suffer from the issues of complex configurations, fixed operation mode as well as low efficiency. Here, we propose a general strategy to design dual-modes vortex beam generator by using metasurfaces with polarization-dependent transmission and reflection properties. Combining the focusing and vortex functionalities, we design/fabricate a type of compact dual-modes vortex beam generator operating at both reflection/transmission sides of the system. Experimental results demonstrate that the designed metadevice can switch freely and independently between the reflective vortex with topological charge m 1  = 2 and transmissive vortex with m 2  = 1. Moreover, the metadevice exhibits very high efficiencies of 91% and 85% for the reflective and transmissive case respectively. Our findings open a door for multifunctional metadevices with high performances, which indicate wide applications in modern integration-optics and wireless communication systems.

  2. Investigation of beam transmission in A 9SDH-2 3.0 MV NEC pelletron tandem accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Deoli, Naresh T.; Kummari, Venkata C.; Pacheco, Jose L.; Duggan, Jerome L.; Glass, Gary A.; McDaniel, Floyd D.; Reinert, Tilo; Rout, Bibhudutta; Weathers, Duncan L. [Ion Beam Modification And Analysis Laboratory, Department of Physics, University of North Texas, Denton, Texas 76203 (United States)

    2013-04-19

    Electrostatic tandem accelerators are widely used to accelerate ions for experiments in materials science such as high energy ion implantation, materials modification, and analyses. Many applications require high beam current as well as high beam brightness at the target; thus, maximizing the beam transmission through such electrostatic accelerators becomes important. The Ion Beam Modification and Analysis Laboratory (IBMAL) at University of North Texas is equipped with four accelerators, one of which is a 9SDH-2 3.0 MV National Electrostatic Corporation (NEC) Pelletron Registered-Sign tandem accelerator. The tandem accelerator is equipped with three ion sources: one radio frequency-He ion source (Alphatross) and two ion sources of Cs-sputter type, the SNICS II (Source of Negative Ions by Cesium Sputtering) and a Cs-sputter source for trace-element accelerator based mass spectrometry. This work presents a detailed study of the beam transmission of hydrogen, silicon, and silver ions through the accelerator using the SNICS ion source with injection energies ranging from 20 keV to 70 keV. The beam transmission is quantified for three different terminal voltages: 1.5 MV, 2.0 MV and 2.5 MV. For a given terminal voltage, it has been found that beam transmission is strongly dependent on the ion source injector potential. Details of experiments and data analysis are presented.

  3. Adaptive motion compensation in sonar array processing

    NARCIS (Netherlands)

    Groen, J.

    2006-01-01

    In recent years, sonar performance has mainly improved via a significant increase in array ap-erture, signal bandwidth and computational power. This thesis aims at improving sonar array processing techniques based on these three steps forward. In applications such as anti-submarine warfare and mine

  4. Sonar path correction in synthetic aperture processing

    NARCIS (Netherlands)

    Groen, J.; Hansen, R.E.; Sabel, J.C.

    2003-01-01

    In the next generation of mine hunting sonars, in particular on Autonomous Underwater Vehicles (AUVs), Synthetic Aperture Sonar (SAS) will play an important role. The benefit of SAS is to increase resolution and signal-tonoise ratio by coherent processing of successive pings. A challenge in SAS is

  5. Long range echo classification for minehunting sonars

    NARCIS (Netherlands)

    Theije, P.A.M. de; Groen, J.; Sabel, J.C.

    2006-01-01

    This paper focesus on single-ping classification of sea mines, at a range of about 400 m, and combining a hull mounted sonar (HMS) and a propelled variable-depth sonar (PDVS). The deleoped classifier is trained and tested on a set of simulated realistic echoes of mines and non-mines. As the mines

  6. Mass-stiffness substructuring of an elastic metasurface for full transmission beam steering

    Science.gov (United States)

    Lee, Hyuk; Lee, Jun Kyu; Seung, Hong Min; Kim, Yoon Young

    2018-03-01

    The metasurface concept has a significant potential due to its novel wavefront-shaping functionalities that can be critically useful for ultrasonic and solid wave-based applications. To achieve the desired functionalities, elastic metasurfaces should cover full 2π phase shift and also acquire full transmission within subwavelength scale. However, they have not been explored much with respect to the elastic regime, because the intrinsic proportionality of mass-stiffness within the continuum elastic media causes an inevitable trade-off between abrupt phase shift and sufficient transmission. Our goal is to engineer an elastic metasurface that can realize an inverse relation between (amplified) effective mass and (weakened) stiffness in order to satisfy full 2π phase shift as well as full transmission. To achieve this goal, we propose a continuum elastic metasurface unit cell that is decomposed into two substructures, namely a mass-tuning substructure with a local dipolar resonator and a stiffness-tuning substructure composed of non-resonant multiply-perforated slits. We demonstrate analytically, numerically, and experimentally that this unique substructured unit cell can satisfy the required phase shift with high transmission. The substructuring enables independent tuning of the elastic properties over a wide range of values. We use a mass-spring model of the proposed continuum unit cell to investigate the working mechanism of the proposed metasurface. With the designed metasurface consisting of substructured unit cells embedded in an aluminum plate, we demonstrate that our metasurface can successfully realize anomalous steering and focusing of in-plane longitudinal ultrasonic beams. The proposed substructuring concept is expected to provide a new principle for the design of general elastic metasurfaces that can be used to efficiently engineer arbitrary wave profiles.

  7. Atomic spin resonance in a rubidium beam obliquely incident to a transmission magnetic grating

    International Nuclear Information System (INIS)

    Hatakeyama, A; Goto, K

    2016-01-01

    We studied atomic spin resonance induced by atomic motion in a spatially periodic magnetostatic field. A rubidium atomic beam, with a velocity of about 400 m s −1 , was obliquely incident to a transmission magnetic grating that produced a spatially periodic magnetic field. The magnetic grating was formed by a magnetic thin film on a polyimide substrate that had multiple slits at 150 μm intervals. The atoms experienced field oscillation, depending on their velocity and the field period when passing through the grating, and underwent magnetic resonance. Resonance spectra obtained with a perpendicular magnetization film were in clear contrast to ones obtained with an in-plane magnetization film. The former exhibited resonance peaks at odd multiples of the frequency, determined by the velocity over the period, while the latter had dips at the same frequencies. (paper)

  8. Automated grain mapping using wide angle convergent beam electron diffraction in transmission electron microscope for nanomaterials.

    Science.gov (United States)

    Kumar, Vineet

    2011-12-01

    The grain size statistics, commonly derived from the grain map of a material sample, are important microstructure characteristics that greatly influence its properties. The grain map for nanomaterials is usually obtained manually by visual inspection of the transmission electron microscope (TEM) micrographs because automated methods do not perform satisfactorily. While the visual inspection method provides reliable results, it is a labor intensive process and is often prone to human errors. In this article, an automated grain mapping method is developed using TEM diffraction patterns. The presented method uses wide angle convergent beam diffraction in the TEM. The automated technique was applied on a platinum thin film sample to obtain the grain map and subsequently derive grain size statistics from it. The grain size statistics obtained with the automated method were found in good agreement with the visual inspection method.

  9. Slope angle studies from multibeam sonar data on three seamounts in Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.

    Slope angles are powerful morphometric tools. Slope angle studies in manganese nodule areas using the Multi Beam Sonar (MBS) data is useful to the mining geologist. A technique to convert depth grid generated from MBS data to slope angle values data...

  10. A comparative study for different shielding material composition and beam geometry applied to PET facilities: simulated transmission curves

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, Gabriela [Pontificia Univ. Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil). Grupo de Experimentacao e Simulacao Computacional em Fisica Medica; Costa, Paulo Roberto, E-mail: pcosta@if.usp.br [Universidade de Sao Paulo (IF/USP), SP (Brazil). Dept. de Fisica Nuclear. Lab. de Dosimetria das Radiacoes e Fisica Medica

    2013-03-15

    The aim of this work is to simulate transmission data for different beam geometry and material composition in order to evaluate the effect of these parameters on transmission curves. The simulations are focused on outgoing spectra for shielding barriers used in PET facilities. The behavior of the transmission was evaluated as a function of the shielding material composition and thickness using Geant4 Monte Carlo code, version 9.2 p 03.The application was benchmarked for barited mortar and compared to The American Association of Physicists in Medicine (AAPM) data for lead. Their influence on the transmission curves as well the study of the influence of the shielding material composition and beam geometry on the outgoing spectra were performed. Characteristics of transmitted spectra, such as shape, average energy and Half-Value Layer (HVL), were also evaluated. The Geant4 toolkit benchmark for the energy resulting from the positron annihilation phenomena and its application in transmission curves description shown good agreement between data published by American Association on Physicists in Medicine task group 108 and experimental data published by Brazil. The transmission properties for different material compositions were also studied and have shown low dependency with the considered thicknesses. The broad and narrow beams configuration presented significant differences on the result. The fitting parameter for determining the transmission curves equations, according to Archer model is presented for different material. As conclusion were defined that beam geometry has significant influence and the composition has low influence on transmission curves for shielding design for the range of energy applied to PET. (author)

  11. A comparative study for different shielding material composition and beam geometry applied to PET facilities: simulated transmission curves

    International Nuclear Information System (INIS)

    Hoff, Gabriela; Costa, Paulo Roberto

    2013-01-01

    The aim of this work is to simulate transmission data for different beam geometry and material composition in order to evaluate the effect of these parameters on transmission curves. The simulations are focused on outgoing spectra for shielding barriers used in PET facilities. The behavior of the transmission was evaluated as a function of the shielding material composition and thickness using Geant4 Monte Carlo code, version 9.2 p 03.The application was benchmarked for barited mortar and compared to The American Association of Physicists in Medicine (AAPM) data for lead. Their influence on the transmission curves as well the study of the influence of the shielding material composition and beam geometry on the outgoing spectra were performed. Characteristics of transmitted spectra, such as shape, average energy and Half-Value Layer (HVL), were also evaluated. The Geant4 toolkit benchmark for the energy resulting from the positron annihilation phenomena and its application in transmission curves description shown good agreement between data published by American Association on Physicists in Medicine task group 108 and experimental data published by Brazil. The transmission properties for different material compositions were also studied and have shown low dependency with the considered thicknesses. The broad and narrow beams configuration presented significant differences on the result. The fitting parameter for determining the transmission curves equations, according to Archer model is presented for different material. As conclusion were defined that beam geometry has significant influence and the composition has low influence on transmission curves for shielding design for the range of energy applied to PET. (author)

  12. Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

    International Nuclear Information System (INIS)

    Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

    1993-01-01

    Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently the authors used a MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r b < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v perpendicular/c = β perpendicular ≤ 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. The authors' success with the MITL technology led them to investigate the application to higher energy accelerator designs. They have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30-50-ns FWHM output pulse

  13. Application of Magnetically Insulated Transmission Lines for high current, high voltage electron beam accelerators

    International Nuclear Information System (INIS)

    Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

    1991-01-01

    Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r ρ < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v perpendicular/c = β perpendicular ≤ 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30--50 ns FWHM output pulse. 10 refs

  14. Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

    Science.gov (United States)

    Shope, S. L.; Mazarakis, M. G.; Frost, C. A.; Poukey, J. W.; Turman, B. N.

    Self Magnetically Insulated Transmission Lines (MITL) adders were used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r(sub rho) less than 2 cm), 11 - 15 MeV, 50 - 100-kA beams with a small transverse velocity v(perpendicular)/c = beta(perpendicular) less than or equal to 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30 - 50 ns FWHM output pulse.

  15. SU-D-213-02: Characterization of the Effect of a New Commercial Transmission Detector On Radiotherapy Beams

    International Nuclear Information System (INIS)

    Cheung, J; Morin, O

    2015-01-01

    Purpose: To evaluate the influence of a new commercial transmission detector on radiotherapy beams of various energies. Methods: A transmission detector designed for online treatment monitoring was characterized on a TrueBeam STx linear accelerator with 6MV, 6FFF, 10MV, and 10FFF beams. Measurements of beam characteristics including percentage depth doses (PDDs), inplane and crossplane off-axis profiles at different depths, transmission factors, and skin dose were acquired at field sizes of 3×3cm, 5×5m, 10×10cm, and 20×20cm at 100cm and 80cm source-to-surface distance (SSD). All measurements were taken with and without the transmission detector in the path of the beam. A CC04 chamber was used for all profile and transmission factor measurements. Skin dose was assessed at 100cm, 90cm, and 80cm SSD and using a variety of detectors (Roos and Markus parallel-plate chambers, and OSLD). Results: The PDDs showed small differences between the unperturbed and perturbed beams for both 100cm and 80cm SSD (≤4mm dmax difference and <1.2% average profile difference). The differences were larger for the flattened beams and at larger field sizes. The off-axis profiles showed similar trends. The penumbras looked similar with and without the transmission detector. Comparisons in the central 80% of the profile showed a maximum average (maximum) profile difference between all field sizes of 0.756% (1.535%) and 0.739% (3.682%) for 100cm and 80cm SSD, respectively. The average measured skin dose at 100cm (80cm) SSD for 10×10cm field size was <4% (<35%) dose increase for all energies. For 20×20cm field size, this value increased to <10% (≤45%). Conclusion: The transmission detector has minimal effect on the clinically relevant radiotherapy beams for IMRT and VMAT (field sizes 10×10cm and less). For larger field sizes, some perturbations are observable which would need to be assessed for clinical impact. The authors of this publication has research support from IBA Dosimetry

  16. SU-D-213-02: Characterization of the Effect of a New Commercial Transmission Detector On Radiotherapy Beams

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, J; Morin, O [University of California San Francisco, San Francisco, CA (United States)

    2015-06-15

    Purpose: To evaluate the influence of a new commercial transmission detector on radiotherapy beams of various energies. Methods: A transmission detector designed for online treatment monitoring was characterized on a TrueBeam STx linear accelerator with 6MV, 6FFF, 10MV, and 10FFF beams. Measurements of beam characteristics including percentage depth doses (PDDs), inplane and crossplane off-axis profiles at different depths, transmission factors, and skin dose were acquired at field sizes of 3×3cm, 5×5m, 10×10cm, and 20×20cm at 100cm and 80cm source-to-surface distance (SSD). All measurements were taken with and without the transmission detector in the path of the beam. A CC04 chamber was used for all profile and transmission factor measurements. Skin dose was assessed at 100cm, 90cm, and 80cm SSD and using a variety of detectors (Roos and Markus parallel-plate chambers, and OSLD). Results: The PDDs showed small differences between the unperturbed and perturbed beams for both 100cm and 80cm SSD (≤4mm dmax difference and <1.2% average profile difference). The differences were larger for the flattened beams and at larger field sizes. The off-axis profiles showed similar trends. The penumbras looked similar with and without the transmission detector. Comparisons in the central 80% of the profile showed a maximum average (maximum) profile difference between all field sizes of 0.756% (1.535%) and 0.739% (3.682%) for 100cm and 80cm SSD, respectively. The average measured skin dose at 100cm (80cm) SSD for 10×10cm field size was <4% (<35%) dose increase for all energies. For 20×20cm field size, this value increased to <10% (≤45%). Conclusion: The transmission detector has minimal effect on the clinically relevant radiotherapy beams for IMRT and VMAT (field sizes 10×10cm and less). For larger field sizes, some perturbations are observable which would need to be assessed for clinical impact. The authors of this publication has research support from IBA Dosimetry.

  17. Modeling of transmission and DLG factors for a TrueBeam STX; Modelagem dos fatores de transmissão e DLG para um TrueBeam STX

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Laís B.; Pavan, Guilherme A.; Camargo, André V.; Santoni, Letícia M.; Silva, Diego C. S. A. [Hospital de Câncer de Barretos, SP (Brazil)

    2017-07-01

    For the rounded leaf-end Multi Leaf Collimator (MLC), the Eclipse planning system (Varian) requires the measurement of the Transmission Factor (FT) and Dosimetric Leaf Gap (DLG) for Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT). The use of these factors obtained by the methodology proposed by Varian may not guarantee the best agreement in quality assurance (QA) of patients, while the modeling of these factors makes it possible to obtain an 'optimal' value by reducing the differences between doses measured / calculated. The objective of this work was to measure the FT and DLG of a TrueBeam accelerator (TB) with different setups and detectors, model these parameters and validate the results applying the AAPM-TG119 methodology using the Portal Dosimetry (PD) system. To obtain FT and DLG (6MV, 6FFF, 10MV and 10FFF), DICOM plans supplied by Varian and Farmer ionization chamber and CC13 were used in different setups. For the modeling, the dose measured with the Farmer chamber was initially used in VMAT plans for prostate and head and neck. From the obtained data, interactively the values of the FT and DLG were altered by searching for a higher oil index (> 95%) in the 1% 1mm criterion using the PD. Finally, all planning of TG119 with IMRT and VMAT were measured using PD. The measured values were: 6X [(FT = 1.1% / 1.0%) (DLG = 0.044cm / 0.12cm)], 10X [(FT = 1.3% / 1.3% (FT = 0.93% / 0.4%) (DLG = 0.036cm / 0.05cm)], 10FFF [(FT = 1.14% / 1.05%) (DLG = 0.048 Cm / 0.05cm)]. The mean acceptance percentages for the gamma criterion 1% 1mm of the TG119 schedules with VMAT / IMRT after modeling were 6X: 96% / 76%; 10X: 98% / 95%; 6FFF: 97% / 87%; 10FFF: 97% / 82%. The modeling of FT and DLG is useful to improve the accuracy of patient quality assurance, but the choice of detector and the technique used (VMAT or IMRT) are determinant and lead to different results. A balance should be found according to the routine of the

  18. Radar, sonar, and holography an introduction

    CERN Document Server

    Kock, Winston E

    1974-01-01

    Radar, Sonar, and Holography: An Introduction provides an introduction to the technology of radar and sonar. Because the new science of holography is affecting both these fields quite strongly, the book includes an explanation of the fundamental principles underlying this new art (including the subjects of wave coherence, interference, and diffraction) and of the hologram process itself. Finally, numerous examples are discussed which show how holography is providing new horizons to radar and sonar systems. The book thus also provides a simple approach to the new technology of holography. The

  19. Bats coordinate sonar and flight behavior as they forage in open and cluttered environments

    DEFF Research Database (Denmark)

    Falk, Benjamin; Jakobsen, Lasse; Surlykke, Annemarie

    2014-01-01

    Echolocating bats use active sensing as they emit sounds and listen to the returning echoes to probe their environment for navigation, obstacle avoidance and pursuit of prey. The sensing behavior of bats includes the planning of 3D spatial trajectory paths, which are guided by echo information....... The temporal patterning of sonar sound groups was related to path planning around obstacles in the forest. Together, these results contribute to our understanding of how bats coordinate echolocation and flight behavior to represent and navigate their environment........ In this study, we examined the relationship between active sonar sampling and flight motor output as bats changed environments from open space to an artificial forest in a laboratory flight room. Using high-speed video and audio recordings, we reconstructed and analyzed 3D flight trajectories, sonar beam aim...

  20. Airborne Low-Frequency Sonar (ALFS) Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The ALFS lab is dedicated to support acoustic data analysis and processing software support to the AN/AQS-22 dipping sonar system. It includes stand-alone Software...

  1. Influence of the Integral Quality Monitor transmission detector on high energy photon beams: A multi-centre study.

    Science.gov (United States)

    Casar, Bozidar; Pasler, Marlies; Wegener, Sonja; Hoffman, David; Talamonti, Cinzia; Qian, Jianguo; Mendez, Ignasi; Brojan, Denis; Perrin, Bruce; Kusters, Martijn; Canters, Richard; Pallotta, Stefania; Peterlin, Primoz

    2017-09-01

    The influence of the Integral Quality Monitor (IQM) transmission detector on photon beam properties was evaluated in a preclinical phase, using data from nine participating centres: (i) the change of beam quality (beam hardening), (ii) the influence on surface dose, and (iii) the attenuation of the IQM detector. For 6 different nominal photon energies (4 standard, 2 FFF) and square field sizes from 1×1cm 2 to 20×20cm 2 , the effect of IQM on beam quality was assessed from the PDD 20,10 values obtained from the percentage dose depth (PDD) curves, measured with and without IQM in the beam path. The change in surface dose with/without IQM was assessed for all available energies and field sizes from 4×4cm 2 to 20×20cm 2 . The transmission factor was calculated by means of measured absorbed dose at 10cm depth for all available energies and field sizes. (i) A small (0.11-0.53%) yet statistically significant beam hardening effect was observed, depending on photon beam energy. (ii) The increase in surface dose correlated with field size (pphoton energies except for 18MV. The change in surface dose was smaller than 3.3% in all cases except for the 20×20cm 2 field and 10MV FFF beam, where it reached 8.1%. (iii) For standard beams, transmission of the IQM showed a weak dependence on the field size, and a pronounced dependence on the beam energy (0.9412 for 6MV to 0.9578 for 18MV and 0.9440 for 6MV FFF; 0.9533 for 10MV FFF). The effects of the IQM detector on photon beam properties were found to be small yet statistically significant. The magnitudes of changes which were found justify treating IQM either as tray factors within the treatment planning system (TPS) for a particular energy or alternatively as modified outputs for specific beam energy of linear accelerators, which eases the introduction of the IQM into clinical practice. Copyright © 2017. Published by Elsevier GmbH.

  2. Influence of the Integral Quality Monitor transmission detector on high energy photon beams. A multi-centre study

    Energy Technology Data Exchange (ETDEWEB)

    Casar, Bozidar [Institute of Oncology, Ljubljana (Slovenia). Dept. of Radiation Physics; Pasler, Marlies [Lake Constance Radiation Oncology Center, Singen and Friedrichshafen (Germany); Wegener, Sonja [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; and others

    2017-10-01

    The influence of the Integral Quality Monitor (IQM) transmission detector on photon beam properties was evaluated in a preclinical phase, using data from nine participating centres: (i) the change of beam quality (beam hardening), (ii) the influence on surface dose, and (iii) the attenuation of the IQM detector. For 6 different nominal photon energies (4 standard, 2 FFF) and square field sizes from 1 x 1 cm{sup 2} to 20 x 20 cm{sup 2}, the effect of IQM on beam quality was assessed from the PDD{sub 20,10} values obtained from the percentage dose depth (PDD) curves, measured with and without IQM in the beam path. The change in surface dose with/without IQM was assessed for all available energies and field sizes from 4 x 4 cm{sup 2} to 20 x 20 cm{sup 2}. The transmission factor was calculated by means of measured absorbed dose at 10 cm depth for all available energies and field sizes. (i) A small (0.11-0.53%) yet statistically significant beam hardening effect was observed, depending on photon beam energy. (ii) The increase in surface dose correlated with field size (p < 0.01) for all photon energies except for 18 MV. The change in surface dose was smaller than 3.3% in all cases except for the 20 x 20 cm{sup 2} field and 10 MV FFF beam, where it reached 8.1%. (iii) For standard beams, transmission of the IQM showed a weak dependence on the field size, and a pronounced dependence on the beam energy (0.9412 for 6 MV to 0.9578 for 18 MV and 0.9440 for 6 MV FFF; 0.9533 for 10 MV FFF). The effects of the IQM detector on photon beam properties were found to be small yet statistically significant. The magnitudes of changes which were found justify treating IQM either as tray factors within the treatment planning system (TPS) for a particular energy or alternatively as modified outputs for specific beam energy of linear accelerators, which eases the introduction of the IQM into clinical practice.

  3. Void fraction measurements in two-phase flow by transmission and scattering of a neutrons beam

    International Nuclear Information System (INIS)

    Souza, M.C.L.

    1984-01-01

    Calibration curves have been obtained which supply average values of void fraction (α) of water-steam two-phase mixtures for bubble, slug, annular and invert annular flow states. The measurements were carried out in simulated models of lucite-air for the steady-state, using the techniques of transmission and diffusion of a thermal neutrons beam. The calibration curves obtained were used for measurements of void fraction in a circuit containing two-phase water-air mixtures, in upward concurrent flow, for slug flow (P sub(max) = 1,06 bar) and annular flow (P sub(max) = 1,33 bar), using the same techniques. In both of the systems, a test section made up of an aluminium (99,9%) tube was used with internal diameter of 25,25 mm and 2,0 mm wall thichness. The beam of neutrons was obtained from a 5 Ci isotopic Am-Be source, thermalised in a cylindrical moderator of paraffin of 500 mm diameter (with H/D=1) which was covered by 2 mm thick cadmium sheets and having in its centre a parallepeliped made from high density polyethilene with the dimensions 240 x 240 x 144 mm. The neutrons escape through a rectangular collimator of 53,0 x 25,25 mm, with a length of 273 mm cut out of a single block of borated paraffin (32% of H 3 BO 3 ). The experimental results are in good agreement with theorical models in published literature. (Author) [pt

  4. A risk function for behavioral disruption of Blainville's beaked whales (Mesoplodon densirostris from mid-frequency active sonar.

    Directory of Open Access Journals (Sweden)

    David Moretti

    Full Text Available There is increasing concern about the potential effects of noise pollution on marine life in the world's oceans. For marine mammals, anthropogenic sounds may cause behavioral disruption, and this can be quantified using a risk function that relates sound exposure to a measured behavioral response. Beaked whales are a taxon of deep diving whales that may be particularly susceptible to naval sonar as the species has been associated with sonar-related mass stranding events. Here we derive the first empirical risk function for Blainville's beaked whales (Mesoplodon densirostris by combining in situ data from passive acoustic monitoring of animal vocalizations and navy sonar operations with precise ship tracks and sound field modeling. The hydrophone array at the Atlantic Undersea Test and Evaluation Center, Bahamas, was used to locate vocalizing groups of Blainville's beaked whales and identify sonar transmissions before, during, and after Mid-Frequency Active (MFA sonar operations. Sonar transmission times and source levels were combined with ship tracks using a sound propagation model to estimate the received level (RL at each hydrophone. A generalized additive model was fitted to data to model the presence or absence of the start of foraging dives in 30-minute periods as a function of the corresponding sonar RL at the hydrophone closest to the center of each group. This model was then used to construct a risk function that can be used to estimate the probability of a behavioral change (cessation of foraging the individual members of a Blainville's beaked whale population might experience as a function of sonar RL. The function predicts a 0.5 probability of disturbance at a RL of 150 dBrms re µPa (CI: 144 to 155 This is 15dB lower than the level used historically by the US Navy in their risk assessments but 10 dB higher than the current 140 dB step-function.

  5. Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode.

    Science.gov (United States)

    Bücker, K; Picher, M; Crégut, O; LaGrange, T; Reed, B W; Park, S T; Masiel, D J; Banhart, F

    2016-12-01

    High temporal resolution transmission electron microscopy techniques have shown significant progress in recent years. Using photoelectron pulses induced by ultrashort laser pulses on the cathode, these methods can probe ultrafast materials processes and have revealed numerous dynamic phenomena at the nanoscale. Most recently, the technique has been implemented in standard thermionic electron microscopes that provide a flexible platform for studying material's dynamics over a wide range of spatial and temporal scales. In this study, the electron pulses in such an ultrafast transmission electron microscope are characterized in detail. The microscope is based on a thermionic gun with a Wehnelt electrode and is operated in a stroboscopic photoelectron mode. It is shown that the Wehnelt bias has a decisive influence on the temporal and energy spread of the picosecond electron pulses. Depending on the shape of the cathode and the cathode-Wehnelt distance, different emission patterns with different pulse parameters are obtained. The energy spread of the pulses is determined by space charge and Boersch effects, given by the number of electrons in a pulse. However, filtering effects due to the chromatic aberrations of the Wehnelt electrode allow the extraction of pulses with narrow energy spreads. The temporal spread is governed by electron trajectories of different length and in different electrostatic potentials. High temporal resolution is obtained by excluding shank emission from the cathode and aberration-induced halos in the emission pattern. By varying the cathode-Wehnelt gap, the Wehnelt bias, and the number of photoelectrons in a pulse, tradeoffs between energy and temporal resolution as well as beam intensity can be made as needed for experiments. Based on the characterization of the electron pulses, the optimal conditions for the operation of ultrafast TEMs with thermionic gun assembly are elaborated. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Fabrication of high-transmission microporous membranes by proton beam writing-based molding technique

    Science.gov (United States)

    Wang, Liping; Meyer, Clemens; Guibert, Edouard; Homsy, Alexandra; Whitlow, Harry J.

    2017-08-01

    Porous membranes are widely used as filters in a broad range of micro and nanofluidic applications, e.g. organelle sorters, permeable cell growth substrates, and plasma filtration. Conventional silicon fabrication approaches are not suitable for microporous membranes due to the low mechanical stability of thin film substrates. Other techniques like ion track etching are limited to the production of randomly distributed and randomly orientated pores with non-uniform pore sizes. In this project, we developed a procedure for fabricating high-transmission microporous membranes by proton beam writing (PBW) with a combination of spin-casting and soft lithography. In this approach, focused 2 MeV protons were used to lithographically write patterns consisting of hexagonal arrays of high-density pillars of few μm size in a SU-8 layer coated on a silicon wafer. After development, the pillars were conformably coated with a thin film of poly-para-xylylene (Parylene)-C release agent and spin-coated with polydimethylsiloxane (PDMS). To facilitate demolding, a special technique based on the use of a laser-cut sealing tape ring was developed. This method facilitated the successful delamination of 20-μm thick PDMS membrane with high-density micropores from the mold without rupture or damage.

  7. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    Science.gov (United States)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-09-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρs) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach.

  8. Continuous single pulse resolved measurement of beam diameters at 200 kHz using optical transmission filters

    Science.gov (United States)

    Fruechtenicht, Johannes; Letsch, Andreas; Voss, Andreas; Abdou Ahmed, Marwan; Graf, Thomas

    2012-02-01

    We present a novel laser beam measurement setup which allows the determination of the beam diameter for each single pulse of a pulsed laser beam at repetition rates of up to 200 kHz. This is useful for online process-parameter control e.g. in micromachining or for laser source characterization. Basically, the developed instrument combines spatial transmission filters specially designed for instantaneous optical determination of the second order moments of the lateral intensity distribution of the light beam and photodiodes coupled to customized electronics. The acquisition is computer-based, enabling real-time operation for online monitoring or control. It also allows data storage for a later analysis and visualization of the measurement results. The single-pulse resolved beam diameter can be measured and recorded without any interruption for an unlimited number of pulses. It is only limited by the capacity of the data storage means. In our setup a standard PC and hard-disk provided 2 hours uninterrupted operation and recording of varying beam diameters at 200 kHz. This is about three orders of magnitude faster than other systems. To calibrate our device we performed experiments in cw and pulsed regimes and the obtained results were compared to those obtained with a commercial camera based system. Only minor deviations of the beam diameter values between the two instruments were observed, proving the reliability of our approach.

  9. Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode

    Energy Technology Data Exchange (ETDEWEB)

    Bücker, K.; Picher, M.; Crégut, O. [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS, Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France); LaGrange, T. [Interdisciplinary Centre for Electron Microscopy, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); Reed, B.W.; Park, S.T.; Masiel, D.J. [Integrated Dynamic Electron Solutions, Inc., 5653 Stoneridge Drive 117, Pleasanton, CA 94588 (United States); Banhart, F., E-mail: florian.banhart@ipcms.unistra.fr [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS, Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France)

    2016-12-15

    High temporal resolution transmission electron microscopy techniques have shown significant progress in recent years. Using photoelectron pulses induced by ultrashort laser pulses on the cathode, these methods can probe ultrafast materials processes and have revealed numerous dynamic phenomena at the nanoscale. Most recently, the technique has been implemented in standard thermionic electron microscopes that provide a flexible platform for studying material's dynamics over a wide range of spatial and temporal scales. In this study, the electron pulses in such an ultrafast transmission electron microscope are characterized in detail. The microscope is based on a thermionic gun with a Wehnelt electrode and is operated in a stroboscopic photoelectron mode. It is shown that the Wehnelt bias has a decisive influence on the temporal and energy spread of the picosecond electron pulses. Depending on the shape of the cathode and the cathode-Wehnelt distance, different emission patterns with different pulse parameters are obtained. The energy spread of the pulses is determined by space charge and Boersch effects, given by the number of electrons in a pulse. However, filtering effects due to the chromatic aberrations of the Wehnelt electrode allow the extraction of pulses with narrow energy spreads. The temporal spread is governed by electron trajectories of different length and in different electrostatic potentials. High temporal resolution is obtained by excluding shank emission from the cathode and aberration-induced halos in the emission pattern. By varying the cathode-Wehnelt gap, the Wehnelt bias, and the number of photoelectrons in a pulse, tradeoffs between energy and temporal resolution as well as beam intensity can be made as needed for experiments. Based on the characterization of the electron pulses, the optimal conditions for the operation of ultrafast TEMs with thermionic gun assembly are elaborated. - Highlights: • A detailed characterization of electron

  10. Development of a Millimeter-Wave Beam Position and Profile Monitor for Transmission Efficiency Improvement in an ECRH System

    Directory of Open Access Journals (Sweden)

    Shimozuma T.

    2015-01-01

    Full Text Available In a high power Electron Cyclotron Resonance Heating (ECRH system, a long-distance and low-loss transmission system is required to realize effective heating of nuclear fusion-relevant plasmas. A millimeter-wave beam position and profile monitor, which can be used in a high-power, evacuated, and cooled transmission line, is proposed, designed, manufactured, and tested. The beam monitor consists of a reflector, Peltier-device array and a heat-sink. It was tested using simulated electric heater power or gyrotron output power. The data obtained from the monitor were well agreed with the heat source position and profile. The methods of data analysis and mode-content analysis of a propagating millimeter-wave in the corrugated wave-guide are proposed.

  11. Side-Scan-Sonar Points for Hudson River, NY

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Side Scan Point Files. These points correspond to individual pings which produced hte side-scan-sonar backscatter imagery. Sonar data were collected November 6 to...

  12. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Bäcke, Olof, E-mail: obacke@chalmers.se [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden); Lindqvist, Camilla; Diaz de Zerio Mendaza, Amaia [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg (Sweden); Gustafsson, Stefan [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden); Wang, Ergang; Andersson, Mats R.; Müller, Christian [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg (Sweden); Kristiansen, Per Magnus [Institute of Polymer Nanotechnology (INKA), FHNW University of Applied Science and Arts Northwestern Switzerland, 5210 Windisch (Switzerland); Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen (Switzerland); Olsson, Eva, E-mail: eva.olsson@chalmers.se [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden)

    2017-05-15

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV–vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000 kGy. - Highlights: • Thermal stability of a polymer: fullerne blend is increased using electron irradiation. • Using in-situ transmission electron microscopy the nanostructure is studied. • Electron irradiation stops phase separation between the polymer and fullerene. • Electron irradiation quenches the formation and nucleation of fullerene crystals.

  13. Transmission Electron Microscopy of a CMSX-4 Ni-Base Superalloy Produced by Selective Electron Beam Melting

    Directory of Open Access Journals (Sweden)

    Alireza B. Parsa

    2016-10-01

    Full Text Available In this work, the microstructures of superalloy specimens produced using selective electron beam melting additive manufacturing were characterized. The materials were produced using a CMSX-4 powder. Two selective electron beam melting processing strategies, which result in higher and lower effective cooling rates, are described. Orientation imaging microscopy, scanning transmission electron microscopy and conventional high resolution transmission electron microscopy are used to investigate the microstructures. Our results suggest that selective electron beam melting processing results in near equilibrium microstructures, as far as γ′ volume fractions, the formation of small amounts of TCP phases and the partitioning behavior of the alloy elements are concerned. As expected, higher cooling rates result in smaller dendrite spacings, which are two orders of magnitude smaller than observed during conventional single crystal casting. During processing, columnar grains grow in <100> directions, which are rotated with respect to each other. There are coarse γ/γ′ microstructures in high angle boundary regions. Dislocation networks form low angle boundaries. A striking feature of the as processed selective electron beam melting specimens is their high dislocation density. From a fundamental point of view, this opens new possibilities for the investigation of elementary dislocation processes which accompany solidification.

  14. SU-E-T-571: Newly Emerging Integrated Transmission Detector Systems Provide Online Quality Assurance of External Beam Radiation Therapy

    International Nuclear Information System (INIS)

    Hoffman, D; Chung, E; Hess, C; Stern, R; Benedict, S

    2015-01-01

    Purpose: Two newly emerging transmission detectors positioned upstream from the patient have been evaluated for online quality assurance of external beam radiotherapy. The prototype for the Integral Quality Monitor (IQM), developed by iRT Systems GmbH (Koblenz, Germany) is a large-area ion chamber mounted on the linac accessory tray to monitor photon fluence, energy, beam shape, and gantry position during treatment. The ion chamber utilizes a thickness gradient which records variable response dependent on beam position. The prototype of Delta4 Discover™, developed by ScandiDos (Uppsala, Sweden) is a linac accessory tray mounted 4040 diode array that measures photon fluence during patient treatment. Both systems are employable for patient specific QA prior to treatment delivery. Methods: Our institution evaluated the reproducibility of measurements using various beam types, including VMAT treatment plans with both the IQM ion chamber and the Delta4 Discover diode array. Additionally, the IQM’s effect on photon fluence, dose response, simulated beam error detection, and the accuracy of the integrated barometer, thermometer, and inclinometer were characterized. The evaluated photon beam errors are based on the annual tolerances specified in AAPM TG-142. Results: Repeated VMAT treatments were measured with 0.16% reproducibility by the IQM and 0.55% reproducibility by the Delta4 Discover. The IQM attenuated 6, 10, and 15 MV photon beams by 5.43±0.02%, 4.60±0.02%, and 4.21±0.03% respectively. Photon beam profiles were affected <1.5% in the non-penumbra regions. The IQM’s ion chamber’s dose response was linear and the thermometer, barometer, and inclinometer agreed with other calibrated devices. The device detected variations in monitor units delivered (1%), field position (3mm), single MLC leaf positions (13mm), and photon energy. Conclusion: We have characterized two new transmissions detector systems designed to provide in-vivo like measurements upstream

  15. SU-E-T-571: Newly Emerging Integrated Transmission Detector Systems Provide Online Quality Assurance of External Beam Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D; Chung, E; Hess, C; Stern, R; Benedict, S [UC Davis Cancer Center, Sacramento, CA (United States)

    2015-06-15

    Purpose: Two newly emerging transmission detectors positioned upstream from the patient have been evaluated for online quality assurance of external beam radiotherapy. The prototype for the Integral Quality Monitor (IQM), developed by iRT Systems GmbH (Koblenz, Germany) is a large-area ion chamber mounted on the linac accessory tray to monitor photon fluence, energy, beam shape, and gantry position during treatment. The ion chamber utilizes a thickness gradient which records variable response dependent on beam position. The prototype of Delta4 Discover™, developed by ScandiDos (Uppsala, Sweden) is a linac accessory tray mounted 4040 diode array that measures photon fluence during patient treatment. Both systems are employable for patient specific QA prior to treatment delivery. Methods: Our institution evaluated the reproducibility of measurements using various beam types, including VMAT treatment plans with both the IQM ion chamber and the Delta4 Discover diode array. Additionally, the IQM’s effect on photon fluence, dose response, simulated beam error detection, and the accuracy of the integrated barometer, thermometer, and inclinometer were characterized. The evaluated photon beam errors are based on the annual tolerances specified in AAPM TG-142. Results: Repeated VMAT treatments were measured with 0.16% reproducibility by the IQM and 0.55% reproducibility by the Delta4 Discover. The IQM attenuated 6, 10, and 15 MV photon beams by 5.43±0.02%, 4.60±0.02%, and 4.21±0.03% respectively. Photon beam profiles were affected <1.5% in the non-penumbra regions. The IQM’s ion chamber’s dose response was linear and the thermometer, barometer, and inclinometer agreed with other calibrated devices. The device detected variations in monitor units delivered (1%), field position (3mm), single MLC leaf positions (13mm), and photon energy. Conclusion: We have characterized two new transmissions detector systems designed to provide in-vivo like measurements upstream

  16. Optical true-time-delay microwave beam-steering with 1 Gb/s wireless transmission for in-building networks

    NARCIS (Netherlands)

    Cao, Z.; Li, F.; Boom, van den H.P.A.; Tangdiongga, E.; Koonen, A.M.J.

    2013-01-01

    An optical true time delay based microwave beam-steering (OTTD-MBS) scheme integrated with a radio-over-fibre system is demonstrated. Properties of 1Gb/s data wireless transmission with OTTD-MBS are studied.

  17. Dielectric multilayer beam splitter with differential phase shift on transmission and reflection for division-of-amplitude photopolarimeter.

    Science.gov (United States)

    Yuan, Wenjia; Shen, Weidong; Zhang, Yueguang; Liu, Xu

    2014-05-05

    Dielectric multilayer beam splitter with differential phase shift on transmission and reflection for division-of-amplitude photopolarimeter (DOAP) was presented for the first time to our knowledge. The optimal parameters for the beam splitter are Tp = 78.9%, Ts = 21.1% and Δr - Δt = π/2 at 532nm at an angle of incidence of 45°. Multilayer anti-reflection coating with low phase shift was applied to reduce the backside reflection. Different design strategies that can achieve all optimal targets at the wavelength were tested. Two design methods were presented to optimize the differential phase shift. The samples were prepared by ion beam sputtering (IBS). The experimental results show good agreement with those of the design. The ellipsometric parameters of samples were measured in reflection (ψr, Δr) = (26.5°, 135.1°) and (28.2°, 133.5°), as well as in transmission (ψt, Δt) = (62.5°, 46.1°) and (63.5°, 46°) at 532.6nm. The normalized determinant of instrument matrix to evaluate the performance of samples is respectively 0.998 and 0.991 at 532.6nm.

  18. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope.

    Science.gov (United States)

    Bäcke, Olof; Lindqvist, Camilla; de Zerio Mendaza, Amaia Diaz; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R; Müller, Christian; Kristiansen, Per Magnus; Olsson, Eva

    2017-05-01

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV-vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000kGy. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Recent Developments in SOBEK Passive Sonar Technology

    NARCIS (Netherlands)

    Hunter, A.J.; Fillinger, L.; Zampolli, M.; Clarijs, M.C.

    2012-01-01

    Surveillance of waterside locations for protection against threats from small fast surface vessels and underwater intruders is a very relevant but challenging problem. For this reason, the Netherlands Organisation for Applied Scientific Research (TNO) is developing SOBEK – a family of passive sonar

  20. Improving Protection Agains Intruders Using Passive Sonar

    NARCIS (Netherlands)

    Fillinger, L.; Hunter, A.J.; Zampolli, M.; Clarijs, M.C.; Verolme, J.L.

    2011-01-01

    Divers and small vessels are increasingly recognized as a potential threat to high value assets. Harbour and waterside surveillance systems that are used to counter the threat of divers are usually based on active sonar, whose performance can be limited by reverberation in a harbour environment.

  1. Transmission of laser pulses with high output beam quality using step-index fibers having large cladding

    Science.gov (United States)

    Yalin, Azer P; Joshi, Sachin

    2014-06-03

    An apparatus and method for transmission of laser pulses with high output beam quality using large core step-index silica optical fibers having thick cladding, are described. The thick cladding suppresses diffusion of modal power to higher order modes at the core-cladding interface, thereby enabling higher beam quality, M.sup.2, than are observed for large core, thin cladding optical fibers. For a given NA and core size, the thicker the cladding, the better the output beam quality. Mode coupling coefficients, D, has been found to scale approximately as the inverse square of the cladding dimension and the inverse square root of the wavelength. Output from a 2 m long silica optical fiber having a 100 .mu.m core and a 660 .mu.m cladding was found to be close to single mode, with an M.sup.2=1.6. Another thick cladding fiber (400 .mu.m core and 720 .mu.m clad) was used to transmit 1064 nm pulses of nanosecond duration with high beam quality to form gas sparks at the focused output (focused intensity of >100 GW/cm.sup.2), wherein the energy in the core was laser pulses was about 6 ns. Extending the pulse duration provided the ability to increase the delivered pulse energy (>20 mJ delivered for 50 ns pulses) without damaging the silica fiber.

  2. On the threshold conditions for electron beam damage of asbestos amosite fibers in the transmission electron microscope (TEM).

    Science.gov (United States)

    Martin, Joannie; Beauparlant, Martin; Sauvé, Sébastien; L'Espérance, Gilles

    2016-12-01

    Asbestos amosite fibers were investigated to evaluate the damage caused by a transmission electron microscope (TEM) electron beam. Since elemental x-ray intensity ratios obtained by energy dispersive x-ray spectroscopy (EDS) are commonly used for asbestos identification, the impact of beam damage on these ratios was evaluated. It was determined that the magnesium/silicon ratio best represented the damage caused to the fiber. Various tests showed that most fibers have a current density threshold above which the chemical composition of the fiber is modified. The value of this threshold current density varied depending on the fiber, regardless of fiber diameter, and in some cases could not be determined. The existence of a threshold electron dose was also demonstrated. This value was dependent on the current density used and can be increased by providing a recovery period between exposures to the electron beam. This study also established that the electron beam current is directly related to the damage rate above a current density of 165 A/cm 2 . The large number of different results obtained suggest, that in order to ensure that the amosite fibers are not damaged, analysis should be conducted below a current density of 100 A/cm 2 .

  3. Assessing and ameliorating the influence of the electron beam on carbon nanotube oxidation in environmental transmission electron microscopy

    International Nuclear Information System (INIS)

    Koh, Ai Leen; Sinclair, Robert

    2017-01-01

    In this work, we examine how the imaging electron beam can induce damage in carbon nanotubes (CNTs) at varying oxygen gas pressures and electron dose rates using environmental transmission electron microscopy (ETEM). Our studies show that there is a threshold cumulative electron dose which brings about damage in CNTs in oxygen – through removal of their graphitic walls – which is dependent on O_2 pressure, with a 4–5 fold decrease in total electron dose per decade increase at a lower pressure range (10"−"6 to 10"−"5 mbar) and approximately 1.3 –fold decrease per decade increase at a higher pressure range (10"−"3 to 10"0 mbar). However, at a given pressure, damage in CNTs was found to occur even at the lowest dose rate utilized, suggesting the absence of a lower limit for the latter parameter. This study provides guidelines on the cumulative dose required to damage nanotubes in the 10"−"7 mbar to 10"0 mbar pressure regimes, and discusses the role of electron dose rate and total electron dose on beam-induced CNT degradation experiments. - Highlights: • The electron beam ionizes gas molecules in ETEM and affects experimental outcomes. • Beam-induced damage in CNTs occurs at varying O_2 pressures and electron dose rates. • There is a threshold cumulative dose to damage CNTs which depends on O_2 pressure. • At a given pressure, CNT damage occurs even at the electron dose rate utilized.

  4. Effect of thickness of foil strippers in transmission of beams through 15 UD pelletron accelerator at IUAC

    International Nuclear Information System (INIS)

    Ojha, S.; Pankaj Kumar; Gargari, S.; Joshi, R.; Abhilash; Kabiraj, D.; Chopra, S.

    2009-01-01

    15 UD Pelletron accelerator at IUAC, New Delhi is equipped with a foil stripper and a gas stripper at high voltage terminal. Besides these, we have foil stripper assemblies at High Energy Dead Section (HEDS) of Pelletron and after analyser magnet. Incoming negative ion looses electrons when they pass through the strippers at terminal and becomes positively charged. The next foil stripper at HEDS increases the positive charge state of ion by removing more electrons which helps in delivering beams at higher energy. Typical thickness of carbon foils loaded in the foil stripper assembly in the terminal is around 4 microgram per square centimetre (4 μg/cm 2 ). Thicker foils were installed in the terminal assembly to study the effect of thickness of foil on charge state distribution and transmission of ion beams. Charge state distribution of ions produced out of molecular beam was also studied. In this paper we present and discuss the results and observations with thicker foils on ion as well as molecular beams. (author)

  5. Sonar backscatter differentiation of dominant macrohabitat types in a hydrothermal vent field.

    Science.gov (United States)

    Durand, Sébastien; Legendre, Pierre; Juniper, S Kim

    2006-08-01

    Over the past 20 years, sonar remote sensing has opened ways of acquiring new spatial information on seafloor habitat and ecosystem properties. While some researchers are presently working to improve sonar methods so that broad-scale high-definition surveys can be effectively conducted for management purposes, others are trying to use these surveying techniques in more local areas. Because ecosystem management is scale-dependent, there is a need to acquire spatiotemporal knowledge over various scales to bridge the gap between already-acquired point-source data and information available at broader scales. Using a 675-kHz single-pencil-beam sonar mounted on the remotely operated vehicle ROPOS, 2200 m deep on the Juan de Fuca Ridge, East Pacific Rise, five dominant habitat types located in a hydrothermal vent field were identified and characterized by their sonar signatures. The data, collected at different altitudes from 1 to 10 m above the seafloor, were depth-normalized. We compared three ways of handling the echoes embedded in the backscatters to detect and differentiate the five habitat types; we examined the influence of footprint size on the discrimination capacity of the three methods; and we identified key variables, derived from echoes that characterize each habitat type. The first method used a set of variables describing echo shapes, and the second method used as variables the power intensity values found within the echoes, whereas the last method combined all these variables. Canonical discriminant analysis was used to discriminate among the five habitat types using the three methods. The discriminant models were constructed using 70% of the data while the remaining 30% were used for validation. The results showed that footprints 20-30 cm in diameter included a sufficient amount of spatial variation to make the sonar signatures sensitive to the habitat types, producing on average 82% correct classification. Smaller footprints produced lower percentages of

  6. Attenuation maps for SPECT determined using cone beam transmission computed tomography

    International Nuclear Information System (INIS)

    Manglos, S.H.; Bassano, D.A.; Duxbury, C.E.; Capone, R.B.

    1990-01-01

    This paper presents a new method for measuring non-uniform attenuation maps, using a cone beam geometry CT scan acquired on a standard rotating gamma camera normally used for SPECT imaging. The resulting map is intended for use in non-uniform attenuation compensation of SPECT images. The method was implemented using a light-weight point source holder attached to the camera. A cone beam collimator may be used on the gamma camera, but the cone beam CT scans may also be acquired without collimator. In either implementation, the advantages include very high efficiency and resolution limited not by the collimator but by the intrinsic camera resolution (about 4 mm). Several phantoms tested the spatial uniformity, noise, linearity as a function of attenuation coefficient, and spatial resolution. Good quality attenuation maps were obtained, at least for the central slices where no truncation was present

  7. Transmission of a Bessel beam through a circular aperture in an impedance screen

    International Nuclear Information System (INIS)

    Umul, Yusuf Ziya

    2014-01-01

    The scattering effect of a circular aperture, located in an impedance plane, on a Bessel beam is investigated by decomposing the scattered wave into two subcomponents, namely the geometrical optics and diffracted fields. The diffracted waves are investigated with the aid of the geometrical theory of diffraction. The detour parameter is evaluated and the existence zones of the geometrical optics fields are determined. The various aspects of the reflected and transmitted scattered waves, including the self healing of the beam, are studied numerically. (letter)

  8. Cetacean Social Behavioral Response to Sonar Exposure

    Science.gov (United States)

    2015-09-30

    likely a social response which anticipates against potential loss of social cohesion, which may be induced by masking of their communication signals...Discrimination of fast click series produced by Risso’s dolphins for echolocation or communication . Wensveen P. et al (in review). The effectiveness of ramp...up of naval sonar to reduce sound levels received by marine mammals : experimental tests with humpback whales. Kvadsheim et al. (2015). The 3S2

  9. Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Feist, Armin; Bach, Nora; Rubiano da Silva, Nara; Danz, Thomas; Möller, Marcel; Priebe, Katharina E.; Domröse, Till; Gatzmann, J. Gregor; Rost, Stefan; Schauss, Jakob; Strauch, Stefanie; Bormann, Reiner; Sivis, Murat; Schäfer, Sascha, E-mail: sascha.schaefer@phys.uni-goettingen.de; Ropers, Claus, E-mail: claus.ropers@uni-goettingen.de

    2017-05-15

    We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9 Å focused beam diameter, 200 fs pulse duration and 0.6 eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams. - Highlights: • First implementation of an ultrafast TEM employing a nanoscale photocathode. • Localized single photon-photoemission from nanoscopic field emitter yields low emittance ultrashort electron pulses. • Electron pulses focused down to ~9 Å, with a duration of 200 fs and an energy width of 0.6 eV are demonstrated. • Quantitative characterization of ultrafast electron gun emittance and brightness. • A range of applications of high coherence ultrashort electron pulses is shown.

  10. Imaging the interphase of carbon fiber composites using transmission electron microscopy: Preparations by focused ion beam, ion beam etching, and ultramicrotomy

    Directory of Open Access Journals (Sweden)

    Wu Qing

    2015-10-01

    Full Text Available Three sample preparation techniques, focused ion beam (FIB, ion beam (IB etching, and ultramicrotomy (UM were used in comparison to analyze the interphase of carbon fiber/epoxy composites using transmission electron microscopy. An intact interphase with a relatively uniform thickness was obtained by FIB, and detailed chemical analysis of the interphase was investigated by electron energy loss spectroscopy. It shows that the interphase region is 200 nm wide with an increasing oxygen-to-carbon ratio from 10% to 19% and an almost constant nitrogen-to-carbon ratio of about 3%. However, gallium implantation of FIB tends to hinder fine structure analysis of the interphase. For IB etching, the interphase region is observed with transition morphology from amorphous resin to nano-crystalline carbon fiber, but the uneven sample thickness brings difficulty for quantitative chemical analysis. Moreover, UM tends to cause damage and/or deformation on the interphase. These results are meaningful for in-depth understanding on the interphase characteristic of carbon fiber composites.

  11. Assessing and ameliorating the influence of the electron beam on carbon nanotube oxidation in environmental transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Ai Leen, E-mail: alkoh@stanford.edu [Stanford Nano Shared Facilities, Stanford University, Stanford, CA 94305 (United States); Sinclair, Robert [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States)

    2017-05-15

    In this work, we examine how the imaging electron beam can induce damage in carbon nanotubes (CNTs) at varying oxygen gas pressures and electron dose rates using environmental transmission electron microscopy (ETEM). Our studies show that there is a threshold cumulative electron dose which brings about damage in CNTs in oxygen – through removal of their graphitic walls – which is dependent on O{sub 2} pressure, with a 4–5 fold decrease in total electron dose per decade increase at a lower pressure range (10{sup −6} to 10{sup −5} mbar) and approximately 1.3 –fold decrease per decade increase at a higher pressure range (10{sup −3} to 10{sup 0} mbar). However, at a given pressure, damage in CNTs was found to occur even at the lowest dose rate utilized, suggesting the absence of a lower limit for the latter parameter. This study provides guidelines on the cumulative dose required to damage nanotubes in the 10{sup −7} mbar to 10{sup 0} mbar pressure regimes, and discusses the role of electron dose rate and total electron dose on beam-induced CNT degradation experiments. - Highlights: • The electron beam ionizes gas molecules in ETEM and affects experimental outcomes. • Beam-induced damage in CNTs occurs at varying O{sub 2} pressures and electron dose rates. • There is a threshold cumulative dose to damage CNTs which depends on O{sub 2} pressure. • At a given pressure, CNT damage occurs even at the electron dose rate utilized.

  12. Facilities for in situ ion beam studies in transmission electron microscopes

    International Nuclear Information System (INIS)

    Allen, C.W.; Ohnuki, S.; Takahashi, H.

    1993-08-01

    Interfacing an ion accelerator to a transmission electron microscope (TEM) allows the analytical functions of TEM imaging and electron diffraction from very small regions to be employed during ion-irradiation effects studies. At present there are ten such installations in Japan, one in France and one in the USA. General specifications of facilities which are operational in 1993 are summarized, and additional facilities which are planned or being proposed are briefly described

  13. Beam transmission in MP equipment. New measurements. Main effects and application to VIVITRON

    International Nuclear Information System (INIS)

    Haas, F.; Muller, C.; Nadji, A.; Rebmeister, R.

    1989-01-01

    The MP equipment is presented and the vacuum values at different measuring points are indicated. The low energy transmission stage (foil and gas strippers) high energy stage (5, 10, and 15 micro-g/cm 2 foils and gas stripper) are described, as well as the global system. For the Vivitron, in order to reach equilibrium thickness, pression in the stripping channel should be higher than that in the MP channel, and pump power should be planned accordingly [fr

  14. Transmission electron microscopy of nanostructures synthesized by laser and charged particle beam interaction with materials

    International Nuclear Information System (INIS)

    Dey, G. K.

    2011-01-01

    Transmission Electron Microscopy (TEM), because of its ability to image atomic arrangements directly and its ability to give spectroscopic information at similar resolution has emerged as a very powerful tool for understanding the structure of materials at atomic level. TEM has been particularly useful in resolving the interface structures in materials. This form of microscopy is very suitable for resolving the structure and defects in ultrafine microstructures such as those of the nanocrystalline phases. After a brief description of the different characterization abilities of the aberration corrected transmission electron microscope, this presentation describes the results of TEM investigations on nanocrystalline microstructures generated by laser materials interaction and due to interaction of electrons and ions with materials. Excimer laser has become an attractive choice for new and precision application for ablation and deposition in recent times. In this work, a KrF excimer laser having 30 ns pulse width and 600 mJ energy at source has been used to deposit zirconia on Zr-base alloy in order to explore the ability of the thin oxide film to act as a diffusion barrier to hydrogen ingress into the alloy. It has been found that the variation in pressure by an order of three has resulted in maximum influence on the roughness of the laser deposited oxide film that has not been possible to achieve by other parameters within the range of the instrument. Present study has also indicated an interrelation among the roughness, adherence and the film-thickness, where the last one is indicated by the XPS study. Transmission electron microscopy was carried out to study the size, size distribution and defects in the deposited film. Nanocrystalline phases generated by interaction of electron and ion irradiation of Zr based alloys; Ni based alloys and Fe based alloys have been examined in detail by conventional and high resolution transmission electron microscopy. Results of

  15. Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System

    CERN Document Server

    Gentile, C A; Hartfield, J W; Hawryluk, R J; Hegeler, F; Heitzenroeder, P J; Jun, C H; Ku, L P; Lamarche, P H; Myers, M C; Parker, J J; Parsells, R F; Payen, M; Raftopoulos, S; Sethian, J D

    2002-01-01

    The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, , and ) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W centre dot cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated w...

  16. Laser power beaming: an emerging technology for power transmission and propulsion in space

    Science.gov (United States)

    Bennett, Harold E.

    1997-05-01

    A ground based laser beam transmitted to space can be used as an electric utility for satellites. It can significantly increase the electric power available to operate a satellite or to transport it from low earth orbit (LEO) to mid earth or geosynchronous orbits. The increase in electrical power compared to that obtainable from the sun is as much as 1000% for the same size solar panels. An increase in satellite electric power is needed to meet the increasing demands for power caused by the advent of 'direct to home TV,' for increased telecommunications, or for other demands made by the burgeoning 'space highway.' Monetary savings as compared to putting up multiple satellites in the same 'slot' can be over half a billion dollars. To obtain propulsion, the laser power can be beamed through the atmosphere to an 'orbit transfer vehicle' (OTV) satellite which travels back and forth between LEO and higher earth orbits. The OTV will transport the satellite into orbit as does a rocket but does not require the heavy fuel load needed if rocket propulsion is used. Monetary savings of 300% or more in launch costs are predicted. Key elements in the proposed concept are a 100 to 200 kW free- electron laser operating at 0.84 m in the photographic infrared region of the spectrum and a novel adaptive optic telescope.

  17. Design of fused-silica rectangular transmission gratings for polarizing beam splitter based on modal method.

    Science.gov (United States)

    Zhao, Huajun; Yuan, Dairong

    2010-02-10

    Examples of optimal designs for a fused-silica transmitted grating with high-intensity tolerance are discussed. It has the potential of placing up to 99% incident polarized light in a single diffraction order. The modal method has been used to analyze the effective indices for TE and TM polarization propagating through the grating region, and the eigenvalue equation of the modal method is transformed to a new form. It is shown that the effective indices of the first two modes depend on the value of the period under Littrow mounting with filling factor f=0.5. The polarization properties of the polarizing beam splitter are analyzed by rigorous coupled-wave analysis (RCWA) at the wavelength of 1.064 microm. The optimal design perfectly matches the RCWA simulation result.

  18. Tungsten mesh as positron transmission moderator in a monoenergetic positron beam

    International Nuclear Information System (INIS)

    Weng, H.M.; Ling, C.C.; Beling, C.D.; Fung, S.; Cheung, C.K.; Kwan, P.Y.; Hui, I.P.

    2004-01-01

    The slow positron yield has been measured for various tungsten (W) moderator samples from a 22 Na radioactive source. Multi-folded W mesh, W(1 0 0) single crystal foil and W polycrystalline foil samples have been investigated. It is found that the fast to slow conversion efficiency of the W mesh moderator depends on: (1) the annealing pretreatments, (2) the chemical etching duration and (3) the number of the folding layers. With the raw W mesh material having a wire diameter of 20 μm and transmission efficiency of 92.5%, an optimal efficiency of 1.2 x 10 -3 was achieved with 5 min etching duration and a folding number of 12 layers

  19. CW 50W/M2 = 10.9 diode laser source by spectral beam combining based on a transmission grating.

    Science.gov (United States)

    Zhang, Jun; Peng, Hangyu; Fu, Xihong; Liu, Yun; Qin, Li; Miao, Guoqing; Wang, Lijun

    2013-02-11

    An external cavity structure based on the -1st transmission grating is introduced to spectral beam combining a 970 nm diode laser bar. A CW output power of 50.8 W, an electro-optical conversion efficiency of 45%, a spectral beam combining efficiency of 90.2% and a holistic M(2) value of 10.9 are achieved. This shows a way for a diode laser source with several KW power and diffraction-limited beam quality at the same time.

  20. The fusion of large scale classified side-scan sonar image mosaics.

    Science.gov (United States)

    Reed, Scott; Tena, Ruiz Ioseba; Capus, Chris; Petillot, Yvan

    2006-07-01

    This paper presents a unified framework for the creation of classified maps of the seafloor from sonar imagery. Significant challenges in photometric correction, classification, navigation and registration, and image fusion are addressed. The techniques described are directly applicable to a range of remote sensing problems. Recent advances in side-scan data correction are incorporated to compensate for the sonar beam pattern and motion of the acquisition platform. The corrected images are segmented using pixel-based textural features and standard classifiers. In parallel, the navigation of the sonar device is processed using Kalman filtering techniques. A simultaneous localization and mapping framework is adopted to improve the navigation accuracy and produce georeferenced mosaics of the segmented side-scan data. These are fused within a Markovian framework and two fusion models are presented. The first uses a voting scheme regularized by an isotropic Markov random field and is applicable when the reliability of each information source is unknown. The Markov model is also used to inpaint regions where no final classification decision can be reached using pixel level fusion. The second model formally introduces the reliability of each information source into a probabilistic model. Evaluation of the two models using both synthetic images and real data from a large scale survey shows significant quantitative and qualitative improvement using the fusion approach.

  1. Assessing Sonar Performance in Realistic Environments

    Science.gov (United States)

    2012-10-01

    Her Majesty the Queen in Right of Canada (Department of National Defence), 2012 c© Sa Majesté la Reine en droit du Canada (Ministère de la Défense... Victoria Class submarine. Q316 included a number of objectives specific to the ASPIRE project. These included demonstrating the use of gliders for the... Victoria Class C3 Optimization’ for the high level architecture for synthetic environment simulations • 20EA05: ‘Support to CMS: Ruggedized Sonar Test

  2. Digital sonar design in underwater acoustics principles and applications

    CERN Document Server

    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.

  3. Three-dimensional nanofabrication by electron-beam-induced deposition using 200-keV electrons in scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Liu, Z.Q.; Mitsuishi, K.; Furuya, K.

    2005-01-01

    Attempts were made to fabricate three-dimensional nanostructures on and out of a substrate by electron-beam-induced deposition in a 200-kV scanning transmission electron microscope. Structures with parallel wires over the substrate surface were difficult to fabricate due to the direct deposition of wires on both top and bottom surfaces of the substrate. Within the penetration depth of the incident electron beam, nanotweezers were fabricated by moving the electron beam beyond different substrate layers. Combining the deposition of self-supporting wires and self-standing tips, complicated three-dimensional doll-like, flag-like, and gate-like nanostructures that extend out of the substrate were successfully fabricated with one-step or multi-step scans of the electron beam. Effects of coarsening, nucleation, and distortion during electron-beam-induced deposition are discussed. (orig.)

  4. The Insulation Structure of the 1 Megavolt Transmission Line for the ITER Neutral Beam Injector

    International Nuclear Information System (INIS)

    Lorenzi, A. de; Grando, L.; Gobbo, R; Pesavento, G.; Bettini, P.; Specogna, R.; Trevisan, F.

    2006-01-01

    The paper describes the studies and the tests for the development of the insulation structure of the 1 MV-50 A Gas Insulated (SF 6 ) Line of the ITER NBI in the SINGAP configuration. Basically, the Transmission Line for the SinGap configuration consists of a coaxial conductor with the inner electrode polarized at the negative value of 1 MV dc. Despite Transmission Line belongs to the Gas Insulated Switchgear (GIS) family, whose technology is nowadays mature, the design of spacers (usually epoxy post and conical type) for High Voltage DC with the same degree of reliability of spacer for High Voltage AC is far away to be attained, due to the substantial difference between AC and DC voltage electric field configuration and insulation behavior at Epoxy-SF 6 interface. Furthermore, the occurrence of very frequent short circuits during the NBI operation introduces further elements of uncertainty in the design of the insulation structure. The first step was then to assess the capability of standard epoxy spacers to withstand DC voltage with frequent short circuits, in order to determine if the choice of the material is suitable for such an application; a test circuit was set up, with the possibility to generate 200 kV DC and to produce a short-circuit every 15'. The system with the spacers was pressurized with SF 6 at 0.3 MPa. For the interpretation of the experimental results, the spacer has been modeled with commercial (ANSYS TM FEM) and research (Cell Method) numerical codes in order to evaluate both the capacitive and resistive electric field distributions. Once assessed the possibility of using epoxy compounds for the spacer construction, the post and cone spacers have been designed taking into consideration various cases, like electrostatic field configuration, resistive distribution for homogeneous and skin conductivity of the spacer, and for high SF 6 conductivity. In these cases the optimization of the triple point screening has been evaluated, leading to

  5. Characterization of laser beam transmission through a High Density Polyethylene (HDPE) plate

    Science.gov (United States)

    Genna, S.; Leone, C.; Tagliaferri, V.

    2017-02-01

    Infrared (IR) light propagation in semicrystalline polymers involves mechanisms such as reflection, transmission, absorption and internal scattering. These different rates determine either the interaction mechanism, either the temperatures reached in the IR heating processes. Consequently, the knowledge of these rates is fundamental in the development of IR heating processes in order to avoid the polymer's damage and to increase the process energy efficiency. Aim of this work is to assess a simple procedure to determine the rates of absorbed, reflected, transmitted and scattered energy in the case of an unfilled High Density Polyethylene (HDPE) plate. Experimental tests were performed by exposing a HDPE plate, 3 mm in thickness, to a diode laser source, working at the fundamental wavelength of 975 nm. The transmitted power was measured by power meter, the reflected one by applying the Beer-Lambert law to sample of different thickness. IR thermal images were adopted to measure the absorbed ratio. The scattered ratio was measured by energetic balance, as difference between the incoming power and the other ratios. Finally, IR thermal images were adopted to measure the scattered ratio and to validate the procedure.

  6. Low-dose ion-based transmission radiography and tomography for optimization of carbon ion-beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Magallanes Hernandez, Lorena

    2017-02-21

    )), middle (1000 primaries per RP) and low imaging dose (500 primaries per RP) in the radiographic domain, whereas only high dose tomographic acquisitions were experimentally performed. Dedicated Monte Carlo (MC)-based post-processing methods, developed at the Ludwig-Maximilians-Universitaet Muenchen (Munich, Germany), were applied to improve the retrieval of Water Equivalent Thickness (WET) variations in lateral (spatial resolution) and longitudinal (ion range resolution) directions, for iRADs, and rWEPL in the tomographic case. An exhaustive quantitative and qualitative evaluation of the acquired images was made in comparison with the ground-truth and simulated data in terms of physical-dose to the object [Gy], accuracy [% of Relative Error (RE)] and overall image quality [NRMSD]. iRADs were produced with 0.5 to 1 mGy imaging dose and an absolute mean WET-RE within 1.5%. Tomographies of two heterogeneous phantoms were acquired in the high dose regime, yielding 4 Gy imaging dose and a RE in rWEPL below 1%, for a geometry that resembles an anatomical scenario. Nonetheless, the findings in the low dose projection studies indicate that the dose of tomographic acquisitions with the current experimental setup can be reduced down to 0.2 Gy. Furthermore, the improved readout system tests and MC simulations establish the possibility to decrease the dose received by the imaged object by about one order of magnitude down (∝0.03 Gy), which lies in the clinically accepted range. Finally, the ongoing imaging system upgrade and the potential integration with single-ion tracking detectors is outlined. The outcome of this thesis highlights the strengths and weaknesses of ion transmission-imaging with the investigated integration-mode RRD, paving the way to future improvements towards eventual application to the ion-beam therapy clinical work-flow. Although further optimization is still required for clinical application, ion-based transmission-imaging has demonstrated its potentiality to

  7. Low-dose ion-based transmission radiography and tomography for optimization of carbon ion-beam therapy

    International Nuclear Information System (INIS)

    Magallanes Hernandez, Lorena

    2017-01-01

    )), middle (1000 primaries per RP) and low imaging dose (500 primaries per RP) in the radiographic domain, whereas only high dose tomographic acquisitions were experimentally performed. Dedicated Monte Carlo (MC)-based post-processing methods, developed at the Ludwig-Maximilians-Universitaet Muenchen (Munich, Germany), were applied to improve the retrieval of Water Equivalent Thickness (WET) variations in lateral (spatial resolution) and longitudinal (ion range resolution) directions, for iRADs, and rWEPL in the tomographic case. An exhaustive quantitative and qualitative evaluation of the acquired images was made in comparison with the ground-truth and simulated data in terms of physical-dose to the object [Gy], accuracy [% of Relative Error (RE)] and overall image quality [NRMSD]. iRADs were produced with 0.5 to 1 mGy imaging dose and an absolute mean WET-RE within 1.5%. Tomographies of two heterogeneous phantoms were acquired in the high dose regime, yielding 4 Gy imaging dose and a RE in rWEPL below 1%, for a geometry that resembles an anatomical scenario. Nonetheless, the findings in the low dose projection studies indicate that the dose of tomographic acquisitions with the current experimental setup can be reduced down to 0.2 Gy. Furthermore, the improved readout system tests and MC simulations establish the possibility to decrease the dose received by the imaged object by about one order of magnitude down (∝0.03 Gy), which lies in the clinically accepted range. Finally, the ongoing imaging system upgrade and the potential integration with single-ion tracking detectors is outlined. The outcome of this thesis highlights the strengths and weaknesses of ion transmission-imaging with the investigated integration-mode RRD, paving the way to future improvements towards eventual application to the ion-beam therapy clinical work-flow. Although further optimization is still required for clinical application, ion-based transmission-imaging has demonstrated its potentiality to

  8. In Situ Transmission Electron Microscopy Study of Electron Beam-Induced Transformations in Colloidal Cesium Lead Halide Perovskite Nanocrystals

    Science.gov (United States)

    2017-01-01

    An increasing number of studies have recently reported the rapid degradation of hybrid and all-inorganic lead halide perovskite nanocrystals under electron beam irradiation in the transmission electron microscope, with the formation of nanometer size, high contrast particles. The nature of these nanoparticles and the involved transformations in the perovskite nanocrystals are still a matter of debate. Herein, we have studied the effects of high energy (80/200 keV) electron irradiation on colloidal cesium lead bromide (CsPbBr3) nanocrystals with different shapes and sizes, especially 3 nm thick nanosheets, a morphology that facilitated the analysis of the various ongoing processes. Our results show that the CsPbBr3 nanocrystals undergo a radiolysis process, with electron stimulated desorption of a fraction of bromine atoms and the reduction of a fraction of Pb2+ ions to Pb0. Subsequently Pb0 atoms diffuse and aggregate, giving rise to the high contrast particles, as previously reported by various groups. The diffusion is facilitated by both high temperature and electron beam irradiation. The early stage Pb nanoparticles are epitaxially bound to the parent CsPbBr3 lattice, and evolve into nonepitaxially bound Pb crystals upon further irradiation, leading to local amorphization and consequent dismantling of the CsPbBr3 lattice. The comparison among CsPbBr3 nanocrystals with various shapes and sizes evidences that the damage is particularly pronounced at the corners and edges of the surface, due to a lower diffusion barrier for Pb0 on the surface than inside the crystal and the presence of a larger fraction of under-coordinated atoms. PMID:28122188

  9. Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System

    International Nuclear Information System (INIS)

    Gentile, C.A.; Fan, H.M.; Hartfield, J.W.; Hawryluk, R.J.; Hegeler, F.; Heitzenroeder, P.J.; Jun, C.H.; Ku, L.P.; LaMarche, P.H.; Myers, M.C.; Parker, J.J.; Parsells, R.F.; Payen, M.; Raftopoulos, S.; Sethian, J.D.

    2002-01-01

    The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, , and ) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W · cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated with 500 nm thin-film silicon nitride (Si 3 N 4 ), has been fabricated. The window consists of 81 square panes with a thickness of 0.019 mm ± 0.001 mm. Stiffened (orthogonal) sections are 0.065 mm in width and 0.500 mm thick (approximate). Appended drawing (Figure 1) depicts the window configuration. Assessment of silicon (and silicon nitride) material properties and CAD modeling and analysis of the window design suggest that silicon may be a viable solution to inherent parameters and constraints

  10. AWARE Sonar and Sperm Whale Tagging (DE9906, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The AWARE sonar and sperm whale tagging cruise primarily focuses on whales in the continental shelf areas, with the following objectives: 1) Develop a better...

  11. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of upward looking sonar draft data collected by submarines in the Arctic Ocean. It includes data from both U.S. Navy and Royal Navy...

  12. Biologically-inspired radar and sonar lessons from nature

    CERN Document Server

    Balleri, Alessio; Baker, Chris

    2017-01-01

    This book presents some of the recent work that has been carried out to investigate how sophisticated sensing techniques used in nature can be applied to radar and sonar systems to improve their performance.

  13. Textural Segmentation of High-Resolution Sidescan Sonar Images

    National Research Council Canada - National Science Library

    Kalcic, Maria; Bibee, Dale

    1995-01-01

    .... The high resolution of the 455 kHz sonar imagery also provides much information about the surficial bottom sediments, however their acoustic scattering properties are not well understood at high frequencies...

  14. Sonar Headphone Selection for Optimum Performance: An Overview

    National Research Council Canada - National Science Library

    Russotti, Joseph

    1995-01-01

    .... The advantages and disadvantages of open and sealed circumaural headsets and recent developments in noise canceling headsets are discussed, along with the possibility of reducing noise levels in sonar spaces to permit use of higher fidelity headphone designs.

  15. Mid-Frequency Sonar Interactions with Beaked Whales

    National Research Council Canada - National Science Library

    Foote, Kenneth G; Feijoo, Gonzalo R; Rye, Kent; Reidenberg, Joy; Hastings, Mardi

    2007-01-01

    The top-level goal of this project is to build an interactive online modeling and visualization system, called the Virtual Beaked Whale, to enable users to predict mid-frequency sonar-induced acoustic...

  16. AWARE Sonar and Sperm Whale Tagging (DE0007, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The AWARE sonar and sperm whale tagging cruise primarily focuses on whales in the continental shelf areas, with the following objectives: 1) Develop a better...

  17. Side-Scan-Sonar Lines for Hudson River, NY

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Side Scan Sonar and Subbottom Profiler Tracklines. Data was collected November 5 to December 15, 2009, in the estuary north from Saugerties to Troy. Fugro utilized...

  18. Colour Sonar: Multi-Frequency Sidescan Sonar Images of the Seabed in the Inner Sound of the Pentland Firth, Scotland

    Directory of Open Access Journals (Sweden)

    Duncan Tamsett

    2016-03-01

    Full Text Available The backscatter response of a seabed to an incident sonar signal is dependent on the carrier wave frequency: i.e., the seabed is acoustically colourful. Colour is implemented in a prototype three-frequency sidescan sonar system deployed in the Pentland Firth, north Scotland. Sonar amplitude data as a function of frequency are processed to render them an unconfounded effect of the seabed normalized to the response at a reference inclination angle, for colour to be a meaningful property of the seabed. Methods for mapping data at sonar frequencies to optical primary colours for human visualisation are explored. We recommend methods that in our opinion generate colour characteristics harmonious with human vision in which: shadow is white; saturation black; colour shade darkness is proportional to backscatter strength; and shades of red, green and blue are seen in proportion to the backscatter amplitudes of the low-, mid- and high-frequency sonar data. Frequency equalisation is applied to achieve a balance in colour responses in images. The seabed in the survey area is acoustically colourful. Using the “negative BGR” colour mapping method: a weakly backscattering sand dune in the north of the survey area appears as shades of light blue and purple; a strongly backscattering halo of cobbles around the dune appears as shades of hazel brown; a strongly backscattering gravel ridge across the south of the survey area appears as shades of royal blue; and exposed rock as textures ranging in colour from light brown to light blue/green. There is evidence for colour anisotropy (a dependence of colour on the direction of ensonification. Similarities between anthropic colour sonar and the natural sonar of Microchiropteran bats are noted. Bats’ sonar satisfies the information criteria for acoustic colour, and it is hypothesized that it informs a colourfully-perceived world view.

  19. High-Resolution Multibeam Sonar Survey and Interactive 3-D Exploration of the D-Day Wrecks off Normandy

    Science.gov (United States)

    Mayer, L. A.; Calder, B.; Schmidt, J. S.

    2003-12-01

    Historically, archaeological investigations use sidescan sonar and marine magnetometers as initial search tools. Targets are then examined through direct observation by divers, video, or photographs. Magnetometers can demonstrate the presence, absence, and relative susceptibility of ferrous objects but provide little indication of the nature of the target. Sidescan sonar can present a clear image of the overall nature of a target and its surrounding environment, but the sidescan image is often distorted and contains little information about the true 3-D shape of the object. Optical techniques allow precise identification of objects but suffer from very limited range, even in the best of situations. Modern high-resolution multibeam sonar offers an opportunity to cover a relatively large area from a safe distance above the target, while resolving the true three-dimensional (3-D) shape of the object with centimeter-level resolution. The combination of 3-D mapping and interactive 3-D visualization techniques provides a powerful new means to explore underwater artifacts. A clear demonstration of the applicability of high-resolution multibeam sonar to wreck and artifact investigations occurred when the Naval Historical Center (NHC), the Center for Coastal and Ocean Mapping (CCOM) at the University of New Hampshire, and Reson Inc., collaborated to explore the state of preservation and impact on the surrounding environment of a series of wrecks located off the coast of Normandy, France, adjacent to the American landing sectors The survey augmented previously collected magnetometer and high-resolution sidescan sonar data using a Reson 8125 high-resolution focused multibeam sonar with 240, 0.5° (at nadir) beams distributed over a 120° swath. The team investigated 21 areas in water depths ranging from about three -to 30 meters (m); some areas contained individual targets such as landing craft, barges, a destroyer, troop carrier, etc., while others contained multiple smaller

  20. Monitoring upstream sinkhole development by detailed sonar profiling

    Energy Technology Data Exchange (ETDEWEB)

    Rigbey, S. [Acres International Ltd., Niagara Falls, ON (Canada)

    2004-09-01

    This paper describes the development and use of a simple sonar system that has been used by engineers for routine monitoring of small sinkholes on the upstream face of a distressed earth dam. Improper construction of the dam led to the development of several sinkholes measuring 10 to 20 m in diameter upstream from the dam which is founded on deep alluvial sands and gravels. The dam has a central core of silt and leakage varies between 200 and 500 l/s, depending on the water level of the reservoir. The main issues with the upstream blanket are: improper fill placement due to the inability to dewater the area properly; omission of a filter material between the blanket and the alluvium foundation; thin placement of fill and runnelling of the blanket prior to impoundment; and, short upstream extent of the blanket. A downstream weighting toe of material was placed to address the seepage and piping that developed immediately following impounding. Other incidents continued over the years, such as downstream sinkholes, slumping of the crest and repairs about 12 years after construction. An inverter filter was also constructed to better control the seepage. Simple bathymetric surveys conducted by sounding the bottom of the reservoir from the ice surface each winter revealed the presence of several large sinkholes. Although infilling programs were conducted, sinkholes redeveloped after each program. The bathymetric surveys were found to be limited in accuracy and repeatability. Therefore, it was not possible to monitor small developments on a yearly basis. A 3-dimensional seepage model was developed to reconcile some of the unexplained piezometric patterns and to better understand the seepage patterns. However, this was also unsuccessful on its own. A trial sonar survey was then undertaken in 2002 by a Vancouver-based sonar company using an Imagenix profiling sonar head. It was successful in locating a small, previously unknown sinkhole measuring a few metres in diameter at

  1. Review of research on sonar imaging technology in China

    Science.gov (United States)

    Guo, Haitao; Li, Renping; Xu, Feng; Liu, Liyuan

    2013-11-01

    Over the past 20 years, sonar imaging technology particularly for the high-technology sector has been a focus of research, in which many developed countries, especially those with coast lines, have been competing with each other. It has seen a rapid development with increasing widespread applications that has played an important and irreplaceable role in underwater exploration with great prospects for social, economic, scientific, and military benefits. The fundamental techniques underlying sonar imaging, including multi-beamforming, synthetic-aperture and inverse synthetic-aperture sonar, acoustic lensing, and acoustical holography, are described in this paper. This is followed by a comprehensive and systematic review on the advantages and disadvantages of these imaging techniques, applicability conditions, development trends, new ideas, new methods, and improvements in old methods over recent years with an emphasis on the situation in China, along with a bold and constructive prediction to some development characteristics of sonar imaging technology in the near future in China. The perspectives presented in this paper are offered with the idea of providing some degree of guidance and promotion of research on sonar imaging technology.

  2. Passive Sonar Target Detection Using Statistical Classifier and Adaptive Threshold

    Directory of Open Access Journals (Sweden)

    Hamed Komari Alaie

    2018-01-01

    Full Text Available This paper presents the results of an experimental investigation about target detecting with passive sonar in Persian Gulf. Detecting propagated sounds in the water is one of the basic challenges of the researchers in sonar field. This challenge will be complex in shallow water (like Persian Gulf and noise less vessels. Generally, in passive sonar, the targets are detected by sonar equation (with constant threshold that increases the detection error in shallow water. The purpose of this study is proposed a new method for detecting targets in passive sonars using adaptive threshold. In this method, target signal (sound is processed in time and frequency domain. For classifying, Bayesian classification is used and posterior distribution is estimated by Maximum Likelihood Estimation algorithm. Finally, target was detected by combining the detection points in both domains using Least Mean Square (LMS adaptive filter. Results of this paper has showed that the proposed method has improved true detection rate by about 24% when compared other the best detection method.

  3. Characterization of a new transmission detector for patient individualized online plan verification and its influence on 6MV X-ray beam characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Thoelking, Johannes; Sekar, Yuvaraj; Fleckenstein, Jens; Lohr, Frank; Wenz, Frederik; Wertz, Hansjoerg [Heidelberg Univ., University Medical Center Mannheim (Germany). Dept. of Radiation Oncology

    2016-11-01

    Online verification and 3D dose reconstruction on daily patient anatomy have the potential to improve treatment delivery, accuracy and safety. One possible implementation is to recalculate dose based on online fluence measurements with a transmission detector (TD) attached to the linac. This study provides a detailed analysis of the influence of a new TD on treatment beam characteristics. The influence of the new TD on surface dose was evaluated by measurements with an Advanced Markus Chamber (Adv-MC) in the build-up region. Based on Monte Carlo simulations, correction factors were determined to scale down the over-response of the Adv-MC close to the surface. To analyze the effects beyond d{sub max} percentage depth dose (PDD), lateral profiles and transmission measurements were performed. All measurements were carried out for various field sizes and different SSDs. Additionally, 5 IMRT-plans (head and neck, prostate, thorax) and 2 manually created test cases (3 x 3 cm{sup 2} fields with different dose levels, sweeping gap) were measured to investigate the influence of the TD on clinical treatment plans. To investigate the performance of the TD, dose linearity as well as dose rate dependency measurements were performed. With the TD inside the beam an increase in surface dose was observed depending on SSD and field size (maximum of +11%, SSD = 80 cm, field size = 30 x 30 cm{sup 2}). Beyond d{sub max} the influence of the TD on PDDs was below 1%. The measurements showed that the transmission factor depends slightly on the field size (0.893-0.921 for 5 x 5 cm{sup 2} to 30 x 30 cm{sup 2}). However, the evaluation of clinical IMRT-plans measured with and without the TD showed good agreement after using a single transmission factor (γ{sub (2%/2mm)} > 97%, δ{sub ±3%} >95%). Furthermore, the response of TD was found to be linear and dose rate independent (maximum difference <0.5% compared to reference measurements). When placed in the path of the beam, the TD introduced

  4. Sperm whales reduce foraging effort during exposure to 1-2 kHz sonar and killer whale sounds.

    Science.gov (United States)

    Isojunno, Saana; Cure, Charlotte; Kvadsheim, Petter Helgevold; Lam, Frans-Peter Alexander; Tyack, Peter Lloyd; Wensveen, Paul Jacobus; Miller, Patrick James O'Malley

    2016-01-01

    The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantified using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeling showed that tagged whales switched to a non-foraging, non-resting state during both experimental transmissions of low-frequency active sonar from an approaching vessel (LFAS; 1-2 kHz, source level 214 dB re 1 µPa m, four tag records) and playbacks of potential predator (killer whale, Orcinus orca) sounds broadcast at naturally occurring sound levels as a positive control from a drifting boat (five tag records). Time spent in foraging states and the probability of prey capture attempts were reduced during these two types of exposures with little change in overall locomotion activity, suggesting an effect on energy intake with no immediate compensation. Whales switched to the active non-foraging state over received sound pressure levels of 131-165 dB re 1 µPa during LFAS exposure. In contrast, no changes in foraging behavior were detected in response to experimental negative controls (no-sonar ship approach or noise control playback) or to experimental medium-frequency active sonar exposures (MFAS; 6-7 kHz, source level 199 re 1 µPa m, received sound pressure level [SPL] = 73-158 dB re 1 µPa). Similarly, there was no reduction in foraging effort for three whales exposed to incidental, unidentified 4.7-5.1 kHz sonar signals received at lower levels (SPL = 89-133 dB re 1 µPa). These results demonstrate that similar to predation risk, exposure to sonar can affect functional behaviors, and indicate that increased perception of risk with higher source level or lower frequency may modulate how sperm whales respond to anthropogenic sound.

  5. A Mobile Robot Sonar System with Obstacle Avoidance.

    Science.gov (United States)

    1994-03-01

    WITH OBSTACLE - AVOIDANCE __ by __ Patrick Gerard Byrne March 1994 Thesis Advisor : Yutaka Kanayama Approved for public release; distribution is...point p is on a line L whose normal has an orientation a and whose distance from the origin is r (Figure 5). This method has an advantage in expressing...sonar(FRONTR); Wine(&pl); while(hitl I >’- 100.0 11 hitl 1 - 0.0 ){ hitl I = sonar(FRONTR); I skipO; line(&p3); gat- robO (&posit 1); while(positl.x

  6. Design of a 50/50 splitting ratio non-polarizing beam splitter based on the modal method with fused-silica transmission gratings

    Science.gov (United States)

    Zhao, Huajun; Yuan, Dairong; Ming, Hai

    2011-04-01

    The optical design of a beam splitter that has a 50/50 splitting ratio regardless of the polarization is presented. The non-polarizing beam splitter (NPBS) is based on the fused-silica rectangular transmission gratings with high intensity tolerance. The modal method has been used to estimate the effective index of the modes excited in the grating region for TE and TM polarizations. If a phase difference equals an odd multiples of π/2 for the first two modes (i.e. modes 0 and 1), the incident light will be diffracted into the 0 and -1 orders with about 50% and 50% diffraction efficiency for TM and TE polarizations, respectively.

  7. Fabrication of nanostructured transmissive optical devices on ITO-glass with UV1116 photoresist using high-energy electron beam lithography

    Science.gov (United States)

    Williams, Calum; Bartholomew, Richard; Rughoobur, Girish; Gordon, George S. D.; Flewitt, Andrew J.; Wilkinson, Timothy D.

    2016-12-01

    High-energy electron beam lithography for patterning nanostructures on insulating substrates can be challenging. For high resolution, conventional resists require large exposure doses and for reasonable throughput, using typical beam currents leads to charge dissipation problems. Here, we use UV1116 photoresist (Dow Chemical Company), designed for photolithographic technologies, with a relatively low area dose at a standard operating current (80 kV, 40-50 μC cm-2, 1 nAs-1) to pattern over large areas on commercially coated ITO-glass cover slips. The minimum linewidth fabricated was ˜33 nm with 80 nm spacing; for isolated structures, ˜45 nm structural width with 50 nm separation. Due to the low beam dose, and nA current, throughput is high. This work highlights the use of UV1116 photoresist as an alternative to conventional e-beam resists on insulating substrates. To evaluate suitability, we fabricate a range of transmissive optical devices, that could find application for customized wire-grid polarisers and spectral filters for imaging, which operate based on the excitation of surface plasmon polaritons in nanosized geometries, with arrays encompassing areas ˜0.25 cm2.

  8. Synchrotron-based multiple-beam FTIR chemical imaging of a multi-layered polymer in transmission and reflection: towards cultural heritage applications

    Science.gov (United States)

    Unger, Miriam; Mattson, Eric; Schmidt Patterson, Catherine; Alavi, Zahrasadet; Carson, David; Hirschmugl, Carol J.

    2013-04-01

    IRENI (infrared environmental imaging) is a recently commissioned Fourier transform infrared (FTIR) chemical imaging beamline at the Synchrotron Radiation Center in Madison, WI, USA. This novel beamline extracts 320 mrad of radiation, horizontally, from one bending magnet. The optical transport separates and recombines the beam into 12 parallel collimated beams to illuminate a commercial FTIR microspectrometer (Bruker Hyperion 3000) equipped with a focal plane array detector where single pixels in the detector image a projected sample area of either 0.54×0.54 μm2 or 2×2 μm2, depending in the measurement geometry. The 12 beams are partially overlapped and defocused, similar to wide-field microscopy, homogeneously illuminating a relatively large sample area compared to single-beam arrangements. Both transmission and reflection geometries are used to examine a model cross section from a layered polymer material. The compromises for sample preparation and measurement strategies are discussed, and the chemical composition and spatial definition of the layers are distinguished in chemical images generated from data sets. Deconvolution methods that may allow more detailed data analysis are also discussed.

  9. On the environmental impact of continuous active sonar

    NARCIS (Netherlands)

    Vossen, R. van; Spek, E. van der; Dekeling, R.P.A.; Beerens, S.P.; Lam, F.P.A.; Benda Beckmann, A.M. von

    2013-01-01

    Continuous Active Sonar (CAS) is an emerging technology in anti-submarine warfare operations. The feasibility of the technology has been demonstrated and it has been shown that CAS has a potential to reduce false alarm rates in reverberation-limited conditions. Now that the feasibility has been

  10. HULU SUNGAI PERAK BED SEDIMENT MAPPING USING UNDERWATER ACOUSTIC SONAR

    Directory of Open Access Journals (Sweden)

    N. Arriafdi

    2016-09-01

    Full Text Available Development in acoustic survey techniques in particular side scan sonar have revolutionized the way we are able to image, map and understand the riverbed environment. It is now cost effective to image large areas of the riverbed using these techniques and the backscatter image created from surveys provides base line data from which thematic maps of the riverbed environment including maps of morphological geology, can be derived when interpreted in conjunction with in situ sampling data. This article focuses on investigation characteristics of sediments and correlation of side scan backscatter image with signal strength. The interpretation of acoustic backscatter rely on experienced interpretation by eye of grey scale images produced from the data. A 990F Starfish Side Scan Sonar was used to collect and develop a series of sonar images along 6 km of Hulu Sungai Perak. Background sediments could be delineated accurately and the image textures could be linked to the actual river floor appearance through grab sampling. A major difference was found in the acoustic returns from the two research area studies: the upstream area shows much rougher textures. This is due to an actual differences in riverbed roughness, caused by a difference in bottom currents and sediment dynamics in the two areas. The highest backscatter correlates with coarsest and roughness sediment. Result suggest that image based backscatter classification shows considerable promise for interpretation of side scan sonar data for the production of geological maps.

  11. Studies on a Spatialized Audio Interface for Sonar

    Science.gov (United States)

    2011-10-03

    addition of spatialized audio to visual displays for sonar is much akin to the development of talking movies in the early days of cinema and can be...than using the brute-force approach. PCA is one among several techniques that share similarities with the computational architecture of a

  12. Adaptive Port-Starboard Beamforming of Triplet Sonar Arrays

    NARCIS (Netherlands)

    Groen, J.; Beerens, S.P.; Been, R.; Doisy, Y.

    2005-01-01

    Abstract—For a low-frequency active sonar (LFAS) with a triplet receiver array, it is not clear in advance which signal processing techniques optimize its performance. Here, several advanced beamformers are analyzed theoretically, and the results are compared to experimental data obtained in sea

  13. Automatic Detection of Sand Ripple Features in Sidescan Sonar Imagery

    Science.gov (United States)

    2014-07-09

    Among the features used in forensic scientific fingerprint analysis are terminations or bifurcations of print ridges. Sidescan sonar imagery of ripple...always be pathological cases. The size of the blocks of pixels used in determining the ripple wavelength is evident in the output images on the right in

  14. Correlation Based Testing for Passive Sonar Picture Rationalization

    National Research Council Canada - National Science Library

    Mellema, Garfield R

    2007-01-01

    .... The sample correlation coefficient, is a statistical measure of relatedness. This paper describes the application of a test based on that measure to compare tracks produced by a probabilistic data association filter from a set of towed array sonar data. Keywords.

  15. MSPOT a performance optimisation tool for ASW sonar

    NARCIS (Netherlands)

    Beerens, S.P.; Benders, F.P.A.

    2012-01-01

    Several navies are operating or procuring low-frequency active sonar systems (LFAS) as the primary part of their ASW capability. Since LFAS is a relatively new sensor with a performance strongly depending on environmental conditions, the proper operational sensor settings, such as depth and pulse

  16. Sonar: a multibase and parametric interface software for SDI

    International Nuclear Information System (INIS)

    Fonseca Passos, M.C.J. da

    1986-01-01

    Sonar - an automated service for selective dissemination of information (SDI) - developed by the Centro de Informacoes Nucleares (CIN) of the Comissao Nacional de Energia Nuclear (CNEN) is described. Emphasis is given to the multibase feature of the system based on the parametric interface between the system and an external data base reading subroutine. (Author) [pt

  17. Effect of number of of projections on inverse radon transform based image reconstruction by using filtered back-projection for parallel beam transmission tomography

    International Nuclear Information System (INIS)

    Qureshi, S.A.; Mirza, S.M.; Arif, M.

    2007-01-01

    This paper present the effect of number of projections on inverse Radon transform (IRT) estimation using filtered back-projection (FBP) technique for parallel beam transmission tomography. The head phantom and the lung phantom have been used in this work. Various filters used in this study include Ram-Lak, Shepp-Logan, Cosin, Hamming and Hanning filters. The slices have been reconstructed by increasing the number of projections through parallel beam transmission tomography keeping the projections uniformly distributed. The Euclidean and Mean Squared errors and peak signal-to-noise ratio (PSNR) have been analyzed for their sensitiveness as functions of number of projections. It has found that image quality improves with the number of projections but at the cost of the computer time. The error has been minimized to get the best approximation of inverse Radon transform (IRT) as the number of projections is enhanced. The value of PSNR has been found to increase from 8.20 to 24.53 dB as the number of projections is raised from 5 to 180 for head phantom. (author)

  18. In situ transmission electron microscopy analyses of thermally annealed self catalyzed GaAs nanowires grown by molecular beam epitaxy

    DEFF Research Database (Denmark)

    Ambrosini, S.; Wagner, Jakob Birkedal; Booth, Tim

    2011-01-01

    Self catalyzed GaAs nanowires grown on Si-treated GaAs substrates were studied with a transmission electron microscope before and after annealing at 600◦C. At room temperature the nanowires have a zincblende structure and are locally characterized by a high density of rotational twins and stacking...... faults. Selected area diffraction patterns and high-resolution transmission electron microscopy images show that nanowires undergo structural modifications upon annealing, suggesting a decrease of defect density following the thermal treatment....

  19. Transmission characteristics of Bessel-Gaussian vortex beams propagating along both longitudinal and transverse directions in a subway tunnel

    Science.gov (United States)

    Wang, Xiaohui; Song, Yingxiong

    2018-02-01

    By exploiting the non-Kolmogorov model and Rytov approximation theory, a propagation model of Bessel-Gaussian vortex beams (BGVB) propagating in a subway tunnel is derived. Based on the propagation model, a model of orbital angular momentum (OAM) mode probability distribution is established to evaluate the propagation performance when the beam propagates along both longitudinal and transverse directions in the subway tunnel. By numerical simulations and experimental verifications, the influences of the various parameters of BGVB and turbulence on the OAM mode probability distribution are evaluated, and the results of simulations are consistent with the experimental statistics. The results verify that the middle area of turbulence is more beneficial for the vortex beam propagation than the edge; when the BGVB propagates along the longitudinal direction in the subway tunnel, the effects of turbulence on the OAM mode probability distribution can be decreased by selecting a larger anisotropy parameter, smaller coherence length, larger non-Kolmogorov power spectrum coefficient, smaller topological charge number, deeper subway tunnel, lower train speed, and longer wavelength. When the BGVB propagates along the transverse direction, the influences can be also mitigated by adopting a larger topological charge number, less non-Kolmogorov power spectrum coefficient, smaller refractive structure index, shorter wavelength, and shorter propagation distance.

  20. High-Resolution Sonars: What Resolution Do We Need for Target Recognition?

    Directory of Open Access Journals (Sweden)

    Pailhas Yan

    2010-01-01

    Full Text Available Target recognition in sonar imagery has long been an active research area in the maritime domain, especially in the mine-counter measure context. Recently it has received even more attention as new sensors with increased resolution have been developed; new threats to critical maritime assets and a new paradigm for target recognition based on autonomous platforms have emerged. With the recent introduction of Synthetic Aperture Sonar systems and high-frequency sonars, sonar resolution has dramatically increased and noise levels decreased. Sonar images are distance images but at high resolution they tend to appear visually as optical images. Traditionally algorithms have been developed specifically for imaging sonars because of their limited resolution and high noise levels. With high-resolution sonars, algorithms developed in the image processing field for natural images become applicable. However, the lack of large datasets has hampered the development of such algorithms. Here we present a fast and realistic sonar simulator enabling development and evaluation of such algorithms.We develop a classifier and then analyse its performances using our simulated synthetic sonar images. Finally, we discuss sensor resolution requirements to achieve effective classification of various targets and demonstrate that with high resolution sonars target highlight analysis is the key for target recognition.

  1. Sonar Image Enhancements for Improved Detection of Sea Mines

    DEFF Research Database (Denmark)

    Jespersen, Karl; Sørensen, Helge Bjarup Dissing; Zerr, Benoit

    1999-01-01

    In this paper, five methods for enhancing sonar images prior to automatic detection of sea mines are investigated. Two of the methods have previously been published in connection with detection systems and serve as reference. The three new enhancement approaches are variance stabilizing log...... transform, nonlinear filtering, and pixel averaging for speckle reduction. The effect of the enhancement step is tested by using the full prcessing chain i.e. enhancement, detection and thresholding to determine the number of detections and false alarms. Substituting different enhancement algorithms...... in the processing chain gives a precise measure of the performance of the enhancement stage. The test is performed using a sonar image database with images ranging from very simple to very complex. The result of the comparison indicates that the new enhancement approaches improve the detection performance....

  2. Neural network modeling of a dolphin's sonar discrimination capabilities

    OpenAIRE

    Andersen, Lars Nonboe; René Rasmussen, A; Au, WWL; Nachtigall, PE; Roitblat, H.

    1994-01-01

    The capability of an echo-locating dolphin to discriminate differences in the wall thickness of cylinders was previously modeled by a counterpropagation neural network using only spectral information of the echoes [W. W. L. Au, J. Acoust. Soc. Am. 95, 2728–2735 (1994)]. In this study, both time and frequency information were used to model the dolphin discrimination capabilities. Echoes from the same cylinders were digitized using a broadband simulated dolphin sonar signal with the transducer ...

  3. 10 μ m-thick four-quadrant transmissive silicon photodiodes for beam position monitor application: electrical characterization and gamma irradiation effects

    Science.gov (United States)

    Rafí, J. M.; Pellegrini, G.; Quirion, D.; Hidalgo, S.; Godignon, P.; Matilla, O.; Juanhuix, J.; Fontserè, A.; Molas, B.; Pothin, D.; Fajardo, P.

    2017-01-01

    Silicon photodiodes are very useful devices as X-ray beam monitors in synchrotron radiation beamlines. Owing to Si absorption, devices thinner than 10 μ m are needed to achieve transmission over 90% for energies above 10 keV . In this work, new segmented four-quadrant diodes for beam alignment purposes are fabricated on both ultrathin (10 μ m-thick) and bulk silicon substrates. Four-quadrant diodes implementing different design parameters as well as auxiliary test structures (single diodes and MOS capacitors) are studied. An extensive electrical characterization, including current-voltage (I-V) and capacitance-voltage (C-V) techniques, is carried out on non-irradiated and gamma-irradiated devices up to 100 Mrad doses. Special attention is devoted to the study of radiation-induced charge build-up in diode interquadrant isolation dielectric, as well as its impact on device interquadrant resistance. Finally, the devices have been characterized with an 8 keV laboratory X-ray source at 108 ph/s and in BL13-XALOC ALBA Synchroton beamline with 1011 ph/s and energies from 6 to 16 keV . Sensitivity, spatial resolution and uniformity of the devices have been evaluated.

  4. Comparison of blue-green response between transmission-mode GaAsP- and GaAs-based photocathodes grown by molecular beam epitaxy

    Science.gov (United States)

    Gang-Cheng, Jiao; Zheng-Tang, Liu; Hui, Guo; Yi-Jun, Zhang

    2016-04-01

    In order to develop the photodetector for effective blue-green response, the 18-mm-diameter vacuum image tube combined with the transmission-mode Al0.7Ga0.3As0.9 P 0.1/GaAs0.9 P 0.1 photocathode grown by molecular beam epitaxy is tentatively fabricated. A comparison of photoelectric property, spectral characteristic and performance parameter between the transmission-mode GaAsP-based and blue-extended GaAs-based photocathodes shows that the GaAsP-based photocathode possesses better absorption and higher quantum efficiency in the blue-green waveband, combined with a larger surface electron escape probability. Especially, the quantum efficiency at 532 nm for the GaAsP-based photocathode achieves as high as 59%, nearly twice that for the blue-extended GaAs-based one, which would be more conducive to the underwater range-gated imaging based on laser illumination. Moreover, the simulation results show that the favorable blue-green response can be achieved by optimizing the emission-layer thickness in a range of 0.4 μm-0.6 μm. Project supported by the National Natural Science Foundation of China (Grant No. 61301023) and the Science and Technology on Low-Light-Level Night Vision Laboratory Foundation, China (Grant No. BJ2014001).

  5. In Situ Room Temperature Electron-Beam Driven Graphene Growth from Hydrocarbon Contamination in a Transmission Electron Microscope

    Directory of Open Access Journals (Sweden)

    Mark H Rummeli

    2018-05-01

    Full Text Available The excitement of graphene (as well as 2D materials in general has generated numerous procedures for the fabrication of graphene. Here we present a mini-review on a rather less known, but attractive, in situ means to fabricate graphene inside a transmission electron microscope (TEM. This is achieved in a conventional TEM (viz. no sophisticated specimen holders or microscopes are required and takes advantage of inherent hydrocarbon contamination as a carbon source. Both catalyst free and single atom catalyst approaches are reviewed. An advantage of this technique is that not only can the growth process be imaged in situ, but this can also be achieved with atomic resolution. Moreover, in the future, one can anticipate such approaches enabling the growth of nano-materials with atomic precision.

  6. An integrated environment for fast development and performance assessment of sonar image processing algorithms - SSIE

    DEFF Research Database (Denmark)

    Henriksen, Lars

    1996-01-01

    The sonar simulator integrated environment (SSIE) is a tool for developing high performance processing algorithms for single or sequences of sonar images. The tool is based on MATLAB providing a very short lead time from concept to executable code and thereby assessment of the algorithms tested...... of the algorithms is the availability of sonar images. To accommodate this problem the SSIE has been equipped with a simulator capable of generating high fidelity sonar images for a given scene of objects, sea-bed AUV path, etc. In the paper the main components of the SSIE is described and examples of different...... processing steps are given...

  7. A Study for Optimum Survey Method of Underwater Structure Using the Dual Sonar Sensor

    Directory of Open Access Journals (Sweden)

    Youngseok Kim

    2017-01-01

    Full Text Available We have developed dual sonar equipment and an improved operating method for improving resolution in order to solve the problems of limitations of the optical equipment and the application method of SSS (side scan sonar in the investigation of damage of underwater structures. We analyzed the influence factors of the resolution of sonar data through the comparison of resolution and data quality in indoor test. Also we confirmed the problems about the overlapping area of the dual sonar. Depth and distance were analyzed as major influencing factors for survey angle. Specimens were scanned while adjusting distance and towfish angle according to depth change in order to verify applicability of the developed dual sonar in the field experiment. Optimal resolution was found to be 3 cm in specimen spacing, and 20 sample data items were extracted. We developed the regression model based on the multiple regression analysis and developed the RealDualSONAR-DAQ tool, the dual sonar optimum operating method program based on proposed correlation equations. We can use the developed tools to get the value of the major influencing factors for dual sonar operation and obtain high quality sonar data to analyze damage of underwater structures.

  8. Swath sonar mapping of Earth's submarine plate boundaries

    Science.gov (United States)

    Carbotte, S. M.; Ferrini, V. L.; Celnick, M.; Nitsche, F. O.; Ryan, W. B. F.

    2014-12-01

    The recent loss of Malaysia Airlines flight MH370 in an area of the Indian Ocean where less than 5% of the seafloor is mapped with depth sounding data (Smith and Marks, EOS 2014) highlights the striking lack of detailed knowledge of the topography of the seabed for much of the worlds' oceans. Advances in swath sonar mapping technology over the past 30 years have led to dramatic improvements in our capability to map the seabed. However, the oceans are vast and only an estimated 10% of the seafloor has been mapped with these systems. Furthermore, the available coverage is highly heterogeneous and focused within areas of national strategic priority and community scientific interest. The major plate boundaries that encircle the globe, most of which are located in the submarine environment, have been a significant focus of marine geoscience research since the advent of swath sonar mapping. While the location of these plate boundaries are well defined from satellite-derived bathymetry, significant regions remain unmapped at the high-resolutions provided by swath sonars and that are needed to study active volcanic and tectonic plate boundary processes. Within the plate interiors, some fossil plate boundary zones, major hotspot volcanoes, and other volcanic provinces have been the focus of dedicated research programs. Away from these major tectonic structures, swath mapping coverage is limited to sparse ocean transit lines which often reveal previously unknown deep-sea channels and other little studied sedimentary structures not resolvable in existing low-resolution global compilations, highlighting the value of these data even in the tectonically quiet plate interiors. Here, we give an overview of multibeam swath sonar mapping of the major plate boundaries of the globe as extracted from public archives. Significant quantities of swath sonar data acquired from deep-sea regions are in restricted-access international archives. Open access to more of these data sets would

  9. Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea

    Science.gov (United States)

    Leifer, Ira; Chernykh, Denis; Shakhova, Natalia; Semiletov, Igor

    2017-06-01

    Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes spanning 0.019 to 1.1 L s-1 to derive the in situ calibration curve (Q(σ)). These nonlinear curves related flux (Q) to sonar return (σ) for a multibeam echosounder (MBES) and a single-beam echosounder (SBES) for a range of depths. The analysis demonstrated significant multiple bubble acoustic scattering - precluding the use of a theoretical approach to derive Q(σ) from the product of the bubble σ(r) and the bubble size distribution where r is bubble radius. The bubble plume σ occurrence probability distribution function (Ψ(σ)) with respect to Q found Ψ(σ) for weak σ well described by a power law that likely correlated with small-bubble dispersion and was strongly depth dependent. Ψ(σ) for strong σ was largely depth independent, consistent with bubble plume behavior where large bubbles in a plume remain in a focused core. Ψ(σ) was bimodal for all but the weakest plumes. Q(σ) was applied to sonar observations of natural arctic Laptev Sea seepage after accounting for volumetric change with numerical bubble plume simulations. Simulations addressed different depths and gases between calibration and seep plumes. Total mass fluxes (Qm) were 5.56, 42.73, and 4.88 mmol s-1 for MBES data with good to reasonable agreement (4-37 %) between the SBES and MBES systems. The seepage flux occurrence probability distribution function (Ψ(Q)) was bimodal, with weak Ψ(Q) in each seep area well described by a power law, suggesting primarily minor bubble plumes. The seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.

  10. Space power transmission

    Energy Technology Data Exchange (ETDEWEB)

    Kuribayashi, Shizuma [Mitsubishi Heavy Industries, Ltd., Tokyo, (Japan)

    1989-10-05

    There being a conception to utilize solar energy by use of a space power station (SPS), a method to bring that universal grace to mankind is wireless energy transmission. The wireless energy transmission is regarded to be microwave transmission or laser beam transmission. The microwave transmission is to transmit 2.45GHz band microwave from the SPS to a receiving station on the ground to meet power demand on earth. The microwave, as small in attenuation in atmosphere and resistant against rain and cloud, is made candidate and, however, problematic in influence on organism, necessary large area of receiving antenna and many other points to be studied. While the laser transmission, as more convergent of beam than the microwave transmission, is advantageous with enabling the receiving area to be small and, however, disadvantageous with being not resistant against dust, rain and cloud, if used for the energy transmission between the space and earth. 2 refs., 2 figs.

  11. Seafloor Characterisation of the Gakkel Ridge using Multibeam Sonar, Backscatter and Sidescan Data

    Science.gov (United States)

    Hatzky, J.; Schenke, H. W.

    2003-04-01

    The Gakkel Ridge in the Arctic Ocean was the object of the Arctic Mid-Ocean Ridge Expedition (AMORE) which was carried out by the research icebreakers R/V "Polarstern" (Germany) and USCGC "Healy" (USA) in the boreal summer 2001. This largely unexplored mid-ocean ridge (MOR) is of particular scientific interest due to its volcanic activity and tectonic structure. With spreading rates of 13mm/a in the western and 6 mm/a in the eastern part Gakkel Ridge is the slowest spreading MOR on earth (Michael et al., 2001). The surveyed area which is situated between 82°N / 8°W and 87°N / 75°E has a length of 8890 km and a varying width from 18 to 46 km. The range of measured depths reaches from 566 m on the top of a huge seamount to 5673 m in the central rift valley. Prominent underwater features of remarkable morphologic diversity (e.g. small volcanoes embedded in massive ridge flanks) were discovered in this region. One of the most important goals of the expedition was the compilation of a high resolution grid which serves as basis for a three dimensional digital terrain model (DTM), the derivation of contour lines and the production of bathymetric maps. Accordingly, two hull-mounted multibeam sonars were used for the depth data acquisition: the "Hydrosweep DS-2" system onboard "Polarstern" and the "Seabeam 2112" system onboard "Healy". In order to calculate a combined grid out of two independent data sets different technical specifications of both sonar systems (e.g. frequency, opening angle, number of beams, accuracy) had to be taken into account. Dense sea ice cover made the sonar measurements difficult. Thick floes caused hydroacoustic disturbances that heavily debased the data quality. Outliers and blunders of depths and navigation data had to be corrected in a drawn-out post-processing by appropriate software tools. Both echo sounding systems recorded backscatter information and sidescan data during the entire cruise. Onboard "Polarstern" the sub-bottom profiling

  12. 77 FR 52317 - Record of Decision for Surveillance Towed Array Sensor System Low Frequency Active Sonar

    Science.gov (United States)

    2012-08-29

    ... DEPARTMENT OF DEFENSE Department of the Navy Record of Decision for Surveillance Towed Array Sensor System Low Frequency Active Sonar AGENCY: Department of the Navy, DoD. ACTION: Notice of decision... to employ up to four Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) sonar...

  13. Real-time underwater object detection based on an electrically scanned high-resolution sonar

    DEFF Research Database (Denmark)

    Henriksen, Lars

    1994-01-01

    The paper describes an approach to real time detection and tracking of underwater objects, using image sequences from an electrically scanned high-resolution sonar. The use of a high resolution sonar provides a good estimate of the location of the objects, but strains the computers on board, beca...

  14. Towards the low-dose characterization of beam sensitive nanostructures via implementation of sparse image acquisition in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Hwang, Sunghwan; Han, Chang Wan; Ortalan, Volkan; Venkatakrishnan, Singanallur V; Bouman, Charles A

    2017-01-01

    Scanning transmission electron microscopy (STEM) has been successfully utilized to investigate atomic structure and chemistry of materials with atomic resolution. However, STEM’s focused electron probe with a high current density causes the electron beam damages including radiolysis and knock-on damage when the focused probe is exposed onto the electron-beam sensitive materials. Therefore, it is highly desirable to decrease the electron dose used in STEM for the investigation of biological/organic molecules, soft materials and nanomaterials in general. With the recent emergence of novel sparse signal processing theories, such as compressive sensing and model-based iterative reconstruction, possibilities of operating STEM under a sparse acquisition scheme to reduce the electron dose have been opened up. In this paper, we report our recent approach to implement a sparse acquisition in STEM mode executed by a random sparse-scan and a signal processing algorithm called model-based iterative reconstruction (MBIR). In this method, a small portion, such as 5% of randomly chosen unit sampling areas (i.e. electron probe positions), which corresponds to pixels of a STEM image, within the region of interest (ROI) of the specimen are scanned with an electron probe to obtain a sparse image. Sparse images are then reconstructed using the MBIR inpainting algorithm to produce an image of the specimen at the original resolution that is consistent with an image obtained using conventional scanning methods. Experimental results for down to 5% sampling show consistency with the full STEM image acquired by the conventional scanning method. Although, practical limitations of the conventional STEM instruments, such as internal delays of the STEM control electronics and the continuous electron gun emission, currently hinder to achieve the full potential of the sparse acquisition STEM in realizing the low dose imaging condition required for the investigation of beam-sensitive materials

  15. Digital Signal Processing Applied to the Modernization Of Polish Navy Sonars

    Directory of Open Access Journals (Sweden)

    Marszal Jacek

    2014-04-01

    Full Text Available The article presents the equipment and digital signal processing methods used for modernizing the Polish Navy’s sonars. With the rapid advancement of electronic technologies and digital signal processing methods, electronic systems, including sonars, become obsolete very quickly. In the late 1990s a team of researchers of the Department of Marine Electronics Systems, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, began work on modernizing existing sonar systems for the Polish Navy. As part of the effort, a methodology of sonar modernization was implemented involving a complete replacement of existing electronic components with newly designed ones by using bespoke systems and methods of digital signal processing. Large and expensive systems of ultrasound transducers and their dipping and stabilisation systems underwent necessary repairs but were otherwise left unchanged. As a result, between 2001 and 2014 the Gdansk University of Technology helped to modernize 30 sonars of different types.

  16. The Method of a Standalone Functional Verifying Operability of Sonar Control Systems

    Directory of Open Access Journals (Sweden)

    A. A. Sotnikov

    2014-01-01

    Full Text Available This article describes a method of standalone verifying sonar control system, which is based on functional checking of control system operability.The main features of realized method are a development of the valid mathematic model for simulation of sonar signals at the point of hydroacoustic antenna, a valid representation of the sonar control system modes as a discrete Markov model, providing functional object verification in real time mode.Some ways are proposed to control computational complexity in case of insufficient computing resources of the simulation equipment, namely the way of model functionality reduction and the way of adequacy reduction.Experiments were made using testing equipment, which was developed by department of Research Institute of Information Control System at Bauman Moscow State Technical University to verify technical validity of industrial sonar complexes.On-board software was artificially changed to create malfunctions in functionality of sonar control systems during the verifying process in order to estimate verifying system performances.The method efficiency was proved by the theory and experiment results in comparison with the basic methodology of verifying technical systems.This method could be also used in debugging of on-board software of sonar complexes and in development of new promising algorithms of sonar signal processing.

  17. Real-Time Classification of Seagrass Meadows on Flat Bottom with Bathymetric Data Measured by a Narrow Multibeam Sonar System

    Directory of Open Access Journals (Sweden)

    Masahiro Hamana

    2016-01-01

    Full Text Available Seagrass meadows, one of the most important habitats for many marine species, provide essential ecological services. Thus, society must conserve seagrass beds as part of their sustainable development efforts. Conserving these ecosystems requires information on seagrass distribution and relative abundance, and an efficient, accurate monitoring system. Although narrow multibeam sonar systems (NMBSs are highly effective in resolving seagrass beds, post-processing methods are required to extract key data. The purpose of this study was to develop a simple method capable of detecting seagrass meadows and estimating their relative abundance in real time using an NMBS. Because most seagrass meadows grow on sandy seafloors, we proposed a way of discriminating seagrass meadows from the sand bed. We classify meadows into three categories of relative seagrass abundance using the 95% confidence level of beam depths and the depth range of the beam depth. These are respectively two times the standard deviation of beam depths, and the difference between the shallowest and the deepest depths in a 0.5 × 0.5 m grid cell sampled with several narrow beams. We examined Zostera caulescens Miki, but this simple NMBS method of seagrass classification can potentially be used to map seagrass meadows with longer shoots of other species, such as Posidonia, as both have gas filled cavities.

  18. Dependence of some transmission factors on field size and treatment depth in external beam radiation therapy (EBRT) using the theratron equinox 100 cobalt 60 machine

    International Nuclear Information System (INIS)

    Odonkor, P.

    2015-07-01

    The use of beam modifiers in today’s radiotherapy is very important as it attenuates the beam and reduces the dose to the patient; therefore the need to know the amount of attenuation (in terms of a transmission factor) they provide during treatment. The purpose of this research work is to evaluate the variation (or dependence) of the transmission factors (TFs) of block tray and physical wedges (of different angles) as a function of treatment depth and field size using both iso-centric setups, SAD and SSD; and thus compare the results from the two setup techniques. Wedge and tray TF measurements were performed in a full scatter, large water phantom using a 0.04cc ionization chamber and an average photon energy of 1.25MV from a cobalt-60 unit at an SAD/SSD of 100cm at various depths and field sizes with gantry and collimator angles fixed at 0°. From the measurements carried out, the wedge TF of the 15°, 30°, 45°, and 60°, wedges were found to be 0.775±0.005, 0.650±0.010, 0.505±0.015, and 0.280±0.015 respectively; and the tray TF was found to be 0.960±0.003. Also, the results obtained showed that both the wedge TF and the tray TF has a strong linear dependence on treatment depth; however, the variation of the 15°, wedge TF and the tray TF with depth is less significant (less than 2%). Maximum percentage variation for the 15°, wedge for the SAD setup was 1.1% and 1.59% for the SSD setup; and that for the tray was 0.60% for the SAD setup and 0.12% for the SSD setup. Also, the variation of the 15°, 30°, and 45°, wedge TF with field size was less significant (less than 2%); and a weaker dependence was observed with field size as compared to the treatment depth. However, the 60°, wedge showed a significant variation (maximum of 2.22% and 2.88% for the SAD and SSD setups respectively) as an increase in field size was accompanied by an increase in its wedge TF. Also though the tray TF graphically showed a strong linear dependence on field size the

  19. Detailed characterisation of focused ion beam induced lateral damage on silicon carbide samples by electrical scanning probe microscopy and transmission electron microscopy

    Science.gov (United States)

    Stumpf, F.; Abu Quba, A. A.; Singer, P.; Rumler, M.; Cherkashin, N.; Schamm-Chardon, S.; Cours, R.; Rommel, M.

    2018-03-01

    The lateral damage induced by focused ion beam on silicon carbide was characterized using electrical scanning probe microscopy (SPM), namely, scanning spreading resistance microscopy and conductive atomic force microscopy (c-AFM). It is shown that the damage exceeds the purposely irradiated circles with a radius of 0.5 μm by several micrometres, up to 8 μm for the maximum applied ion dose of 1018 cm-2. Obtained SPM results are critically compared with earlier findings on silicon. For doses above the amorphization threshold, in both cases, three different areas can be distinguished. The purposely irradiated area exhibits resistances smaller than the non-affected substrate. A second region with strongly increasing resistance and a maximum saturation value surrounds it. The third region shows the transition from maximum resistance to the base resistance of the unaffected substrate. It correlates to the transition from amorphized to defect-rich to pristine crystalline substrate. Additionally, conventional transmission electron microscopy (TEM) and annular dark-field STEM were used to complement and explain the SPM results and get a further understanding of the defect spreading underneath the surface. Those measurements also show three different regions that correlate well with the regions observed from electrical SPM. TEM results further allow to explain observed differences in the electrical results for silicon and silicon carbide which are most prominent for ion doses above 3 × 1016 cm-2. Furthermore, the conventional approach to perform current-voltage measurements by c-AFM was critically reviewed and several improvements for measurement and analysis process were suggested that result in more reliable and impactful c-AFM data.

  20. Transmission of broad W/Rh and W/Al (target/filter) x-ray beams operated at 25-49 kVp through common shielding materials.

    Science.gov (United States)

    Li, Xinhua; Zhang, Da; Liu, Bob

    2012-07-01

    To provide transmission data for broad 25-39 kVp (kilovolt peak) W/Rh and 25-49 kVp W/Al (target/filter, W-tungsten, Rh-rhodium, and Al-aluminum) x-ray beams through common shielding materials, such as lead, concrete, gypsum wallboard, wood, steel, and plate glass. The unfiltered W-target x-ray spectra measured on a Selenia Dimensions system (Hologic Inc., Bedford, MA) set at 20-49 kVp were, respectively, filtered using 50-μm Rh and 700-μm Al, and were subsequently used for Monte Carlo calculations. The transmission of broad x-ray beams through shielding materials was simulated using Geant4 low energy electromagnetic physics package with photon- and electron-processes above 250 eV, including photoelectric effect, Compton scattering, and Rayleigh scattering. The calculated transmission data were fitted using Archer equation with a robust fitting algorithm. The transmission of broad x-ray beams through the above-mentioned shielding materials was calculated down to about 10(-5) for 25-39 kVp W/Rh and 25-49 kVp W/Al. The fitted results of α, β, and γ in Archer equation were provided. The α values of kVp ≥ 40 were approximately consistent with those of NCRP Report No. 147. These data provide inputs for the shielding designs of x-ray imaging facilities with W-anode x-ray beams, such as from Selenia Dimensions.

  1. Underwater object classification using scattering transform of sonar signals

    Science.gov (United States)

    Saito, Naoki; Weber, David S.

    2017-08-01

    In this paper, we apply the scattering transform (ST)-a nonlinear map based off of a convolutional neural network (CNN)-to classification of underwater objects using sonar signals. The ST formalizes the observation that the filters learned by a CNN have wavelet-like structure. We achieve effective binary classification both on a real dataset of Unexploded Ordinance (UXOs), as well as synthetically generated examples. We also explore the effects on the waveforms with respect to changes in the object domain (e.g., translation, rotation, and acoustic impedance, etc.), and examine the consequences coming from theoretical results for the scattering transform. We show that the scattering transform is capable of excellent classification on both the synthetic and real problems, thanks to having more quasi-invariance properties that are well-suited to translation and rotation of the object.

  2. The Blackboard Model of Computer Programming Applied to the Interpretation of Passive Sonar Data

    National Research Council Canada - National Science Library

    Liebing, David

    1997-01-01

    ... (location, course, speed, classification, etc.). At present the potential volume of data produced by modern sonar systems is so large that unless some form of computer assistance is provided with the interpretation of this data, information...

  3. U.S. and Australian Mine Warfare Sonar Performance Assessment Using SWAT and Hodgson Models

    National Research Council Canada - National Science Library

    Dubsky, Barbra

    2000-01-01

    The purpose of this thesis was to investigate a shallow coastal region to compile a detailed environmental picture of its sediment composition and water characteristics and from this model MCM sonar...

  4. 'Merge' - A Filter for the Fusion of Dual-Frequency Sidescan Sonar Data

    National Research Council Canada - National Science Library

    Neill, Roger

    1997-01-01

    A filtering and data fusion technique is described which uses the correlation between the two data streams of a dual-frequency sidescan sonar in order to discriminate against noise and preferentially...

  5. A novel underwater dam crack detection and classification approach based on sonar images.

    Science.gov (United States)

    Shi, Pengfei; Fan, Xinnan; Ni, Jianjun; Khan, Zubair; Li, Min

    2017-01-01

    Underwater dam crack detection and classification based on sonar images is a challenging task because underwater environments are complex and because cracks are quite random and diverse in nature. Furthermore, obtainable sonar images are of low resolution. To address these problems, a novel underwater dam crack detection and classification approach based on sonar imagery is proposed. First, the sonar images are divided into image blocks. Second, a clustering analysis of a 3-D feature space is used to obtain the crack fragments. Third, the crack fragments are connected using an improved tensor voting method. Fourth, a minimum spanning tree is used to obtain the crack curve. Finally, an improved evidence theory combined with fuzzy rule reasoning is proposed to classify the cracks. Experimental results show that the proposed approach is able to detect underwater dam cracks and classify them accurately and effectively under complex underwater environments.

  6. A novel underwater dam crack detection and classification approach based on sonar images.

    Directory of Open Access Journals (Sweden)

    Pengfei Shi

    Full Text Available Underwater dam crack detection and classification based on sonar images is a challenging task because underwater environments are complex and because cracks are quite random and diverse in nature. Furthermore, obtainable sonar images are of low resolution. To address these problems, a novel underwater dam crack detection and classification approach based on sonar imagery is proposed. First, the sonar images are divided into image blocks. Second, a clustering analysis of a 3-D feature space is used to obtain the crack fragments. Third, the crack fragments are connected using an improved tensor voting method. Fourth, a minimum spanning tree is used to obtain the crack curve. Finally, an improved evidence theory combined with fuzzy rule reasoning is proposed to classify the cracks. Experimental results show that the proposed approach is able to detect underwater dam cracks and classify them accurately and effectively under complex underwater environments.

  7. Contact-Level Multistatic Sonar Data Simulator for Tracker Performance Assessment

    National Research Council Canada - National Science Library

    Grimmett, Doug; Coraluppi, Stefano

    2006-01-01

    ...). A brief description of the simulation approach is given, which includes simple sonar equation modeling, resulting in sensor-to-sensor target fading effects, as well as contact localization modeling...

  8. Side-Scan_Sonar backscatter tiles for Hudson River, NY (.xtf)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Raw XTF files. Sonar data were collected November 6 to December 15, 2009, in the estuary north from Saugerties to Troy. Data Collection and Processing: The...

  9. Bayesian reconstruction of seafloor shape from side-scan sonar measurements using a Markov Random Field

    OpenAIRE

    Woock, P.; Pak, Alexey

    2014-01-01

    To explore the seafloor, a side-scan sonar emits a directed acoustic signal and then records the returning (reflected) signal intensity as a function of time. The inversion of that process is not unique: multiple shapes may lead to identical measured responses. In this work, we suggest a Bayesian approach to reconstructing the 3D shape of the seafloor from multiple sonar measurements, inspired by the state-of-the-art methods of inverse raytracing that originated in computer vision. The space ...

  10. Sensor Fusion - Sonar and Stereo Vision, Using Occupancy Grids and SIFT

    DEFF Research Database (Denmark)

    Plascencia, Alfredo; Bendtsen, Jan Dimon

    2006-01-01

    to the occupied and empty regions. SIFT (Scale Invariant Feature Transform) feature descriptors are  interpreted using gaussian probabilistic error models. The use of occupancy grids is proposed for representing the sonar  as well as the features descriptors readings. The Bayesian estimation approach is applied...... to update the sonar and the SIFT descriptors' uncertainty grids. The sensor fusion yields a significant reduction in the uncertainty of the occupancy grid compared to the individual sensor readings....

  11. Microwave energy transmission

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Hiroshi [Kyoto Univ. (Japan)

    1989-03-05

    Laying stress on the technological problems and effect on the environment of microwave energy transmission, recent scientific and engineering problems and related subjects are described. Because no fuel is required for the solar power generation, the power generation system can not be considered as an expensive one when the unit cost of energy is taken into consideration. Some of the important technological problems in the microwave energy transmission are accurate microwave beam control technology to receiving stations and improvement in the efficiency of transmission system. Microwave energy beam has effects on living bodies, communication, and plasma atmosphere of the earth. Microwave energy transmission using a space flyer unit is scheduled. Its objective is the development of microwave wireless transmission technology and the study of the correlation between high power microwave and ionosphere plasma. Experiments on such a small scale application as a microwave driven space ship to bring results seem also important. 12 refs., 13 figs.

  12. A novel approach to surveying sturgeon using side-scan sonar and occupancy modeling

    Science.gov (United States)

    Flowers, H. Jared; Hightower, Joseph E.

    2013-01-01

    Technological advances represent opportunities to enhance and supplement traditional fisheries sampling approaches. One example with growing importance for fisheries research is hydroacoustic technologies such as side-scan sonar. Advantages of side-scan sonar over traditional techniques include the ability to sample large areas efficiently and the potential to survey fish without physical handling-important for species of conservation concern, such as endangered sturgeons. Our objectives were to design an efficient survey methodology for sampling Atlantic Sturgeon Acipenser oxyrinchus by using side-scan sonar and to developmethods for analyzing these data. In North Carolina and South Carolina, we surveyed six rivers thought to contain varying abundances of sturgeon by using a combination of side-scan sonar, telemetry, and video cameras (i.e., to sample jumping sturgeon). Lower reaches of each river near the saltwater-freshwater interface were surveyed on three occasions (generally successive days), and we used occupancy modeling to analyze these data.We were able to detect sturgeon in five of six rivers by using these methods. Side-scan sonar was effective in detecting sturgeon, with estimated gear-specific detection probabilities ranging from 0.2 to 0.5 and river-specific occupancy estimates (per 2-km river segment) ranging from 0.0 to 0.8. Future extensions of this occupancy modeling framework will involve the use of side-scan sonar data to assess sturgeon habitat and abundance in different river systems.

  13. High resolution low dose transmission electron microscopy real-time imaging and manipulation of nano-scale objects in the electron beam

    Science.gov (United States)

    Brown, Jr., R. Malcolm; Barnes, Zack [Austin, TX; Sawatari, Chie [Shizuoka, JP; Kondo, Tetsuo [Kukuoka, JP

    2008-02-26

    The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

  14. Campargue-type supersonic beam sources : absolute intensities, skimmer transmission and scaling laws for mono-atomic gases He, Ne and Ar

    NARCIS (Netherlands)

    Beijerinck, H.C.W.; van Gerwen, R.J.F.; Kerstel, E.R.T.; Martens, J.F.M.; van Vliembergen, E.J.W.; Smits, M.R.T.; Kaashoek, G.H.

    1985-01-01

    The process of beam formation in a supersonic expansion into a high pressure (10-2 -1 Torr) expansion chamber, a so-called Campargue-type beam source, has been investigated, using the theoretical frame work of an ideal undisturbed expansion as a reference. Absolute values of the centre-line

  15. Beam-Beam Effects

    International Nuclear Information System (INIS)

    Herr, W; Pieloni, T

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities

  16. Biomimetic Sonar for Electrical Activation of the Auditory Pathway

    Directory of Open Access Journals (Sweden)

    D. Menniti

    2017-01-01

    Full Text Available Relying on the mechanism of bat’s echolocation system, a bioinspired electronic device has been developed to investigate the cortical activity of mammals in response to auditory sensorial stimuli. By means of implanted electrodes, acoustical information about the external environment generated by a biomimetic system and converted in electrical signals was delivered to anatomically selected structures of the auditory pathway. Electrocorticographic recordings showed that cerebral activity response is highly dependent on the information carried out by ultrasounds and is frequency-locked with the signal repetition rate. Frequency analysis reveals that delta and beta rhythm content increases, suggesting that sensorial information is successfully transferred and integrated. In addition, principal component analysis highlights how all the stimuli generate patterns of neural activity which can be clearly classified. The results show that brain response is modulated by echo signal features suggesting that spatial information sent by biomimetic sonar is efficiently interpreted and encoded by the auditory system. Consequently, these results give new perspective in artificial environmental perception, which could be used for developing new techniques useful in treating pathological conditions or influencing our perception of the surroundings.

  17. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A; Laird, J S; Bardos, R A; Legge, G J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T; Sekiguchi, H [Electrotechnical Laboratory, Tsukuba (Japan).

    1994-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  18. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  19. Bathymetry mapping using a GPS-sonar equipped remote control boat: Application in waste stabilisation ponds

    Science.gov (United States)

    Coggins, Liah; Ghadouani, Anas; Ghisalberti, Marco

    2014-05-01

    Traditionally, bathymetry mapping of ponds, lakes and rivers have used techniques which are low in spatial resolution, sometimes subjective in terms of precision and accuracy, labour intensive, and that require a high level of safety precautions. In waste stabilisation ponds (WSP) in particular, sludge heights, and thus sludge volume, are commonly measured using a sludge judge (a clear plastic pipe with length markings). A remote control boat fitted with a GPS-equipped sonar unit can improve the resolution of depth measurements, and reduce safety and labour requirements. Sonar devices equipped with GPS technology, also known as fish finders, are readily available and widely used by people in boating. Through the use of GPS technology in conjunction with sonar, the location and depth can be recorded electronically onto a memory card. However, despite its high applicability to the field, this technology has so far been underutilised. In the case of WSP, the sonar can measure the water depth to the top of the sludge layer, which can then be used to develop contour maps of sludge distribution and to determine sludge volume. The coupling of sonar technology with a remotely operative vehicle has several advantages of traditional measurement techniques, particularly in removing human subjectivity of readings, and the sonar being able to collect more data points in a shorter period of time, and continuously, with a much higher spatial resolution. The GPS-sonar equipped remote control boat has been tested on in excess of 50 WSP within Western Australia, and has shown a very strong correlation (R2 = 0.98) between spot readings taken with the sonar compared to a sludge judge. This has shown that the remote control boat with GPS-sonar device is capable of providing sludge bathymetry with greatly increased spatial resolution, while greatly reducing profiling time. Remotely operated vehicles, such as the one built in this study, are useful for not only determining sludge

  20. Applying multibeam sonar and mathematical modeling for mapping seabed substrate and biota of offshore shallows

    Science.gov (United States)

    Herkül, Kristjan; Peterson, Anneliis; Paekivi, Sander

    2017-06-01

    Both basic science and marine spatial planning are in a need of high resolution spatially continuous data on seabed habitats and biota. As conventional point-wise sampling is unable to cover large spatial extents in high detail, it must be supplemented with remote sensing and modeling in order to fulfill the scientific and management needs. The combined use of in situ sampling, sonar scanning, and mathematical modeling is becoming the main method for mapping both abiotic and biotic seabed features. Further development and testing of the methods in varying locations and environmental settings is essential for moving towards unified and generally accepted methodology. To fill the relevant research gap in the Baltic Sea, we used multibeam sonar and mathematical modeling methods - generalized additive models (GAM) and random forest (RF) - together with underwater video to map seabed substrate and epibenthos of offshore shallows. In addition to testing the general applicability of the proposed complex of techniques, the predictive power of different sonar-based variables and modeling algorithms were tested. Mean depth, followed by mean backscatter, were the most influential variables in most of the models. Generally, mean values of sonar-based variables had higher predictive power than their standard deviations. The predictive accuracy of RF was higher than that of GAM. To conclude, we found the method to be feasible and with predictive accuracy similar to previous studies of sonar-based mapping.

  1. Development of Discrete Power Supply with Charge Pump Method for High Powered Sonar System

    Directory of Open Access Journals (Sweden)

    Kristian Ismail

    2012-07-01

    Full Text Available Power supply is one of the electronic devices that can provide electric energy for electronic systems or other systems. There are several types of power supplies that can be applied depend on the requirement and functions. One example is the use of power supply for sonar systems. Sonar system is a device which can be used to detect a target under water. The sonar system is an electronic circuit that requires a power supply with specific characteristics when the sonar functions as a transmitter and a receiver in the specific span time (when on and the specific lag time (when off. This paper discusses the design of power supply for high-powered sonar systems with discrete methods in which high power supply is only applied when the acoustic waves radiated under water. Charge pump was used to get the appropriate output voltage from lower input voltage. Charge pump utilized a combination of series and parallel connections of capacitors. The working mode of this power supply used the lag time as the calculation of time to charge charge pump capacitors in parallel while the span time was used for the calculation of discharging the charge pump capacitors in series.

  2. Transmission and compression of an intense relativistic electron beam produced by a converging annular diode with return current feedback through the cathode. Pt. 2. The experiments

    International Nuclear Information System (INIS)

    Kelly, J.G.; Schuch, R.L.

    1976-02-01

    The complete results of the experiments with the converging annular diode within return current fedback through the cathode (Triax) are reported herein. The diode was designed to focus a relativistic high-current electron beam to a small focus. It did confirm the Triaxial theory detailed in Part I, and it did achieve a factor of 10 areal compression with 50% efficiency (which was below expectations). There were two principal reasons for this shortfall. First, the rapid diode plasma motion of 10 cm/μsec that was discovered necessitated the use of larger A-K gaps than expected and led to thicker beam sheets than are needed for good focusing. Second, the intrinsic angular spread of the electrons, even from the best cathode surfaces, introduced excessive angular momentum into the beam so that only a minor portion of the electrons could reach the axis. However, the yield of useful information about diode physics in general and about the influence of prepulse, the role of diode plasmas, the motion of energetic beams within conducting boundaries, diode emission properties, and diode diagnostic techniques in particle has had a significant and useful impact on the electron beam program at Sandia

  3. Detection to the DepositFan Occurring in the Sun Moon Lake Using Geophysical Sonar Data

    Science.gov (United States)

    Mimi, L.

    2014-12-01

    Located in central Taiwan, the Sun Moon Lake is an U-shaped basin with the waters capacity for 138.68 × 106m³. The water is input through two underground tunnels from the Wu-Jie dam in the upstream of the Zhuo-shui river. Although the Wu-Jie dam has been trying to keep the tunnels transporting clean water into the lake, the water is still mixed with muds. The silty water brings the deposits accumulating outwards from positions of the tunnel outlets resulting in a deposit fan formed in the lake. To monitor how the fan is accumulated is then very important in terms of environmental issue, tourism and electric power resources. Institute of Oceanography, National Taiwan University therefore conducted projects to use the multi-beam echo sounders to collect bathymetric data, and used the Chirp sub-bottom profiler to explore silted pattern inside the deposit fan. With these data, underwater topographic maps were plotted to observe the shape and internal structure of the fan. Moreover, two sets of data obtained in 2006 and 2012 were used to estimate the siltation magnitude and pattern in the six years period.The multi-beam sounder is Resons Seabat 9001s model; it collects 60 values in each of the swaths positioned by the DGPS method.The sub-bottom profiler is the EdgeTech 3100P Chirp Sonar, its acoustic wave frequency is in 2 ~ 16kHz. The data give the siltation amount in the Sun Moon Lake was around 3× 106 m³, which gives annual siltation rate at 5× 105 m³. The leading edge of the deposit fan has been expanded westwards 2 km from the water outlet since the tunnel was built 70 years ago; however, outside the deposit fan, the siltation shows insignificant amount on the water bottom.In the past few years the siltation mainly occurs outside in the east side of lake, more closer to the water outlets, the terrain had been increased from 744 m to 746 m (748.5 meters is stranded level of the lake).Observing sub-bottom profiler data, we can clearly see the location of the

  4. Behavioral Response of Reef Fish and Green Sea Turtles to Midfrequency Sonar.

    Science.gov (United States)

    Watwood, Stephanie L; Iafrate, Joseph D; Reyier, Eric A; Redfoot, William E

    2016-01-01

    There is growing concern over the potential effects of high-intensity sonar on wild fish populations and commercial fisheries. Acoustic telemetry was employed to measure the movements of free-ranging reef fish and sea turtles in Port Canaveral, FL, in response to routine submarine sonar testing. Twenty-five sheepshead (Archosargus probatocephalus), 28 gray snapper (Lutjanus griseus), and 29 green sea turtles (Chelonia mydas) were tagged, with movements monitored for a period of up to 4 months using an array of passive acoustic receivers. Baseline residency was examined for fish and sea turtles before, during, and after the test event. No mortality of tagged fish or sea turtles was evident from the sonar test event. There was a significant increase in the daily residency index for both sheepshead and gray snapper at the testing wharf subsequent to the event. No broad-scale movement from the study site was observed during or immediately after the test.

  5. Prospects for using sonar for underwater archeology on the Yenisei: surveying a 19th century shipwreck

    Science.gov (United States)

    Goncharov, A. E.; Mednikov, D. M.; Karelin, N. M.; Nasyrov, I. R.

    2016-11-01

    Current progress in underwater archeology is based on a rich arsenal of high-tech appliances, among which sonar technology plays a key role; it enables scientists not only to detect submerged archeological objects, but to examine them in high definition without having to conduct diving operations or use expensive underwater unmanned vehicles. While the majority of sensational scientific discoveries using sonar have been made in saltwater environments, freshwater ones, rivers in particular, have seen limited activity. The river Yenisei in central Siberia contains an unrecorded number of shipwrecks that await being discovered and studied. In this article we focus on the peculiarities of using sonar for detecting archeological sites on the Yenisei. This article is based on the results of the 2016 expedition, which has determined the location of Thames, a 19th century British steam schooner which was wrecked on the Yenisei.

  6. Automated detection of submerged navigational obstructions in freshwater impoundments with hull mounted sidescan sonar

    Science.gov (United States)

    Morris, Phillip A.

    The prevalence of low-cost side scanning sonar systems mounted on small recreational vessels has created improved opportunities to identify and map submerged navigational hazards in freshwater impoundments. However, these economical sensors also present unique challenges for automated techniques. This research explores related literature in automated sonar imagery processing and mapping technology, proposes and implements a framework derived from these sources, and evaluates the approach with video collected from a recreational grade sonar system. Image analysis techniques including optical character recognition and an unsupervised computer automated detection (CAD) algorithm are employed to extract the transducer GPS coordinates and slant range distance of objects protruding from the lake bottom. The retrieved information is formatted for inclusion into a spatial mapping model. Specific attributes of the sonar sensors are modeled such that probability profiles may be projected onto a three dimensional gridded map. These profiles are computed from multiple points of view as sonar traces crisscross or come near each other. As lake levels fluctuate over time so do the elevation points of view. With each sonar record, the probability of a hazard existing at certain elevations at the respective grid points is updated with Bayesian mechanics. As reinforcing data is collected, the confidence of the map improves. Given a lake's current elevation and a vessel draft, a final generated map can identify areas of the lake that have a high probability of containing hazards that threaten navigation. The approach is implemented in C/C++ utilizing OpenCV, Tesseract OCR, and QGIS open source software and evaluated in a designated test area at Lake Lavon, Collin County, Texas.

  7. The transmission theory of electrostatic analyzer in six dimensional phase space and the concept design of a supersensitive mass spectrometer beam line for HI-13 tandem accelerator

    International Nuclear Information System (INIS)

    Guan Xialing; Cao Qingxi; Zhang Jie; Ye Jingping

    1986-01-01

    It follows from the motion equations of charged particle in curvilinear coordinates system that the transfer matrix of electrostatic analyzer was derived in six dimensional phase space. In accordance with these matrixes, the concept design of the supersensitive mass spectrometer beam line for HI-13 tandem accelerator was calculated

  8. Transmission diamond imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, John, E-mail: smedley@bnl.gov; Pinelli, Don; Gaoweia, Mengjia [Brookhaven National Laboratory, Upton, NY (United States); Muller, Erik; Ding, Wenxiang; Zhou, Tianyi [Stony Brook University, Stony Brook, NY (United States); Bohon, Jen [Case Center for Synchrotron Biosciences, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH (United States)

    2016-07-27

    Many modern synchrotron techniques are trending toward use of high flux beams and/or beams which require enhanced stability and precise understanding of beam position and intensity from the front end of the beamline all the way to the sample. For high flux beams, major challenges include heat load management in optics (including the vacuum windows) and a mechanism of real-time volumetric measurement of beam properties such as flux, position, and morphology. For beam stability in these environments, feedback from such measurements directly to control systems for optical elements or to sample positioning stages would be invaluable. To address these challenges, we are developing diamond-based instrumented vacuum windows with integrated volumetric x-ray intensity, beam profile and beam-position monitoring capabilities. A 50 µm thick single crystal diamond has been lithographically patterned to produce 60 µm pixels, creating a >1kilopixel free-standing transmission imaging detector. This device, coupled with a custom, FPGA-based readout, has been used to image both white and monochromatic x-ray beams and capture the last x-ray photons at the National Synchrotron Light Source (NSLS). This technology will form the basis for the instrumented end-station window of the x-ray footprinting beamline (XFP) at NSLS-II.

  9. Modulation, resolution and signal processing in radar, sonar and related systems

    CERN Document Server

    Benjamin, R; Costrell, L

    1966-01-01

    Electronics and Instrumentation, Volume 35: Modulation, Resolution and Signal Processing in Radar, Sonar and Related Systems presents the practical limitations and potentialities of advanced modulation systems. This book discusses the concepts and techniques in the radar context, but they are equally essential to sonar and to a wide range of signaling and data-processing applications, including seismology, radio astronomy, and band-spread communications.Organized into 15 chapters, this volume begins with an overview of the principal developments sought in pulse radar. This text then provides a

  10. Archaeological use of Synthetic Aperture Sonar on deepwater wreck sites in Skagerrak

    DEFF Research Database (Denmark)

    Maarleveld, Thijs J.; Ødegård, Øyvind; Hansen, Roy E.

    2018-01-01

    Marine archaeological surveying in deep waters has so far been challenging, mainly due to operational and technological constraints. The standard tool has been Side Scan Sonar (SSS) towed behind a surface vessel. Synthetic Aperture Sonar (SAS) technology is not subject to the traditional range....../resolution tradeoff, and produces results of considerably higher quality than traditional SSS. In 2015 and 2016 a comprehensive mapping of wrecks in Skagerrak, a large deepwater area off the south coast of Norway was undertaken, using an interferometric SAS system deployed on an autonomous underwater vehicle...

  11. Beam coupling impedance of fast stripline beam kickers

    International Nuclear Information System (INIS)

    Caporaso, G; Chen, Y J; Nelson, A D; Poole, B R

    1999-01-01

    A fast stripline beam kicker is used to dynamically switch a high current electron beam between two beamlines. The transverse dipole impedance of a stripline beam kicker has been previously determined from a simple transmission line model of the structure. This model did not include effects due to the long axial slots along the structure as well as the cavities and coaxial feed transition sections at the ends of the structure. 3-D time domain simulations show that the simple transmission line model underestimates the low frequency dipole beam coupling impedance by about 20% for our structure. In addition, the end cavities and transition sections can exhibit dipole impedances not included in the transmission line model. For high current beams, these additional dipole coupling terms can provide additional beam-induced steering effects not included in the transmission line model of the structure

  12. HIBP primary beam detector

    International Nuclear Information System (INIS)

    Schmidt, T.W.

    1979-01-01

    A position measuring detector was fabricated for the Heavy Ion Beam Probe. The 11 cm by 50 cm detector was a combination of 15 detector wires in one direction and 63 copper bars - .635 cm by 10 cm to measure along an orthogonal axis by means of a current divider circuit. High transmission tungsten meshes provide entrance windows and suppress secondary electrons. The detector dimensions were chosen to resolve the beam position to within one beam diameter

  13. Probability-Based Recognition Framework for Underwater Landmarks Using Sonar Images †.

    Science.gov (United States)

    Lee, Yeongjun; Choi, Jinwoo; Ko, Nak Yong; Choi, Hyun-Taek

    2017-08-24

    This paper proposes a probability-based framework for recognizing underwater landmarks using sonar images. Current recognition methods use a single image, which does not provide reliable results because of weaknesses of the sonar image such as unstable acoustic source, many speckle noises, low resolution images, single channel image, and so on. However, using consecutive sonar images, if the status-i.e., the existence and identity (or name)-of an object is continuously evaluated by a stochastic method, the result of the recognition method is available for calculating the uncertainty, and it is more suitable for various applications. Our proposed framework consists of three steps: (1) candidate selection, (2) continuity evaluation, and (3) Bayesian feature estimation. Two probability methods-particle filtering and Bayesian feature estimation-are used to repeatedly estimate the continuity and feature of objects in consecutive images. Thus, the status of the object is repeatedly predicted and updated by a stochastic method. Furthermore, we develop an artificial landmark to increase detectability by an imaging sonar, which we apply to the characteristics of acoustic waves, such as instability and reflection depending on the roughness of the reflector surface. The proposed method is verified by conducting basin experiments, and the results are presented.

  14. Data fusion from multiple passive sonar nodes for target localisation and false alarm reduction

    NARCIS (Netherlands)

    Hunter, A.J.; Fillinger, L.; Zampolli, M.; Clarijs, M.C.

    2012-01-01

    A PHD particle filter implementation has been detailed for the fusion of measurements from multiple passive sonar nodes. It has been demonstrated on simulated metadata and on experimental passive acoustic data of divers and small boats collected in an operational port environment. Fusion at the

  15. Sonar sound groups and increased terminal buzz duration reflect task complexity in hunting bats

    DEFF Research Database (Denmark)

    Hulgard, K.; Ratcliffe, J. M.

    2016-01-01

    to prey under presumably more difficult conditions. Specifically, we found Daubenton's bats, Myotis daubentonii, produced longer buzzes when aerial-hawking versus water-trawling prey, but that bats taking revolving air- and water-borne prey produced more sonar sound groups than did the bats when taking...

  16. 75 FR 81284 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Draft...

    Science.gov (United States)

    2010-12-27

    ... Frequency and Ultra High Frequency Active SONAR Technology; Draft Programmatic Environmental Assessment and... Programmatic Environmental Assessment (PEA) for the Nationwide Use of High Frequency (HF) and Ultra High... potential impacts of each alternative on the human and natural environments. DATES: Comments and related...

  17. 78 FR 70567 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Final...

    Science.gov (United States)

    2013-11-26

    ... Frequency and Ultra High Frequency Active SONAR Technology; Final Programmatic Environmental Assessment and... each alternative on the human and natural environments. FOR FURTHER INFORMATION CONTACT: If you have... Programmatic Environmental Assessment The scope of the PEA focuses on potential impacts associated with the...

  18. Killer whale presence in relation to naval sonar activity and prey abundance in northern Norway

    NARCIS (Netherlands)

    Kuningas, S.; Kvadsheim, P.H.; Lam, F.P.A.; Miller, P.J.O.

    2013-01-01

    In this study, retrospective data on naval sonar activity and prey abundance were correlated with killer whale sightings within a fjord basin in northern Norway. In addition, passive acoustic and visual marine mammal surveys were conducted before, during, and after a specific navy exercise in 2006.

  19. Advanced signal processing theory and implementation for sonar, radar, and non-invasive medical diagnostic systems

    CERN Document Server

    Stergiopoulos, Stergios

    2009-01-01

    Integrates topics of signal processing from sonar, radar, and medical system technologies by identifying their concept similarities. This book covers non-invasive medical diagnostic system applications, including intracranial ultrasound, a technology that attempts to address non-invasive detection on brain injuries and stroke.

  20. 3S2: Behavioral Response Studies of Cetaceans to Navy Sonar Signals in Norwegian Waters

    Science.gov (United States)

    2015-09-30

    Sonar Signals in Norwegian Waters Peter L. Tyack University of St Andrews School of Biology Scottish Oceans Institute East Sands St Andrews...with a tagged minke whale. Data in the top 4 panels were derived from observations from the trackboat (‘ MOB ’). Note the strong change in diving

  1. Modeling Effectiveness of Gradual Increases in Source Level to Mitigate Effects of Sonar on Marine Mammals

    NARCIS (Netherlands)

    Benda-Beckmann, A.M. von; Wensveen, P.J.; Kvadsheim, P.H.; Lam, F.P.A.; Miller, P.J.O.; Tyack, P.L.; Ainslie, M.A.

    2013-01-01

    Ramp-up or soft-start procedures (i.e., gradual increase in the source level) are used to mitigate the effect of sonar sound on marine mammals, although no one to date has tested whether ramp-up procedures are effective at reducing the effect of sound on marine mammals. We investigated the

  2. Robot path Planning Using  SIFT and Sonar Sensor Fusion

    DEFF Research Database (Denmark)

    Plascencia, Alfredo; Raposo, Hector

    2007-01-01

    and evidential grid maps, respectively. The approach is illustrated using actual measurements from a laboratory robot. The sensory information is obtained from a sonar array and the Scale Invariant Feature Transform (SIFT) algorithm. Finally, the resulting two evidential maps based on Bayes and Dempster theories...

  3. SIMONA: A multi-purpose acoustic data simulator for development and testing of sonar signal processing

    NARCIS (Netherlands)

    Robert, M.K.; Groen, J.; Konijnendijk, N.J.

    2005-01-01

    The development of undersea defence technologies such as sonar relies heavily on the availability of high quality acoustic data. However, data acquisition is particularly expensive as sea trials involve experienced manpower and costly high-tech equipment. Also, at sea, the environment remains

  4. Final report of DOE project "Detection, Localization and Diagnosis of Performance Problems Using PerfSONAR"

    Energy Technology Data Exchange (ETDEWEB)

    Dovrolis, Konstantinos [Georgia Tech

    2014-04-15

    We present the development of a middleware service, called Pythia, that is able to detect, localize, and diagnose performance problems in the network paths that interconnect research sites that are of interest to DOE. The proposed service can analyze perfSONAR data collected from all participating sites.

  5. New sonar waveforms for active torpedo warning using an LFAS system

    NARCIS (Netherlands)

    IJsselmuide, S.P. van; Beerens, S.P.; Doisy, Y.; Deruaz, L.

    2003-01-01

    Low Frequency Active Sonar (LFAS) systems are originally designed for ASW purposes. Although their main purpose is detection of submarines, they can, if adjusted waveforms are transmitted, also be used for detection of small fast moving targets (torpedoes). In this study the Detection,

  6. Selection of a Suitable Wall Pressure Spectrum Model for Estimating Flow-Induced Noise in Sonar Applications

    Directory of Open Access Journals (Sweden)

    V. Bhujanga Rao

    1995-01-01

    Full Text Available Flow-induced structural noise of a sonar dome in which the sonar transducer is housed, constitutes a major source of self-noise above a certain speed of the vessel. Excitation of the sonar dome structure by random pressure fluctuations in turbulent boundary layer flow leads to acoustic radiation into the interior of the dome. This acoustic radiation is termed flow-induced structural noise. Such noise contributes significantly to sonar self-noise of submerged vessels cruising at high speed and plays an important role in surface ships, torpedos, and towed sonars as well. Various turbulent boundary layer wall pressure models published were analyzed and the most suitable analytical model for the sonar dome application selected while taking into account high frequency, fluid loading, low wave number contribution, and pressure gradient effects. These investigations included type of coupling that exists between turbulent boundary layer pressure fluctuations and dome wall structure of a typical sonar dome. Comparison of theoretical data with measured data onboard a ship are also reported.

  7. 2 Tbit/s free-space data transmission on two orthogonal orbital-angular-momentum beams each carrying 25 WDM channels.

    Science.gov (United States)

    Fazal, Irfan M; Ahmed, Nisar; Wang, Jian; Yang, Jeng-Yuan; Yan, Yan; Shamee, Bishara; Huang, Hao; Yue, Yang; Dolinar, Sam; Tur, Moshe; Willner, Alan E

    2012-11-15

    We demonstrate a 2 Tbit/s free-space data link using two orthogonal orbital angular momentum beams each carrying 25 different wavelength-division-multiplexing channels. We measure the performance for different modulation formats, including directly detected 40 Gbit/s nonreturn-to-zero (NRZ) differential phase-shift keying, 40 Gbit/s NRZ on-off keying, and coherently-detected 10 Gbaud NRZ quadrature phase-shift keying, and achieve low bit error rates with penalties less than 5 dB.

  8. Groups of bats improve sonar efficiency through mutual suppression of pulse emissions.

    Directory of Open Access Journals (Sweden)

    Jenna eJarvis

    2013-06-01

    Full Text Available How bats adapt their sonar behavior to accommodate the noisiness of a crowded day roost is a mystery. Some bats change their pulse acoustics to enhance the distinction between theirs and another bat’s echoes, but additional mechanisms are needed to explain the bat sonar system’s exceptional resilience to jamming by conspecifics. Variable pulse repetition rate strategies offer one potential solution to this dynamic problem, but precisely how changes in pulse rate could improve sonar performance in social settings is unclear. Here we show that bats decrease their emission rates as population density increases, following a pattern that reflects a cumulative mutual suppression of each other’s pulse emissions. Playback of artificially-generated echolocation pulses similarly slowed emission rates, demonstrating that suppression was mediated by hearing the pulses of other bats. Slower emission rates did not support an antiphonal emission strategy but did reduce the relative proportion of emitted pulses that overlapped with another bat’s emissions, reducing the relative rate of mutual interference. The prevalence of acoustic interferences occurring amongst bats was empirically determined to be a linear function of population density and mean emission rates. Consequently as group size increased, small reductions in emission rates spread across the group partially mitigated the increase in interference rate. Drawing on lessons learned from communications networking theory we show how modest decreases in pulse emission rates can significantly increase the net information throughput of the shared acoustic space, thereby improving sonar efficiency for all individuals in a group. We propose that an automated acoustic suppression of pulse emissions triggered by bats hearing each other's emissions dynamically optimizes sonar efficiency for the entire group.

  9. Development Of A Method For Measurement Of Total Neutron Cross Sections Based On The Neutron Transmission Method Using A He-3 Counter On Filtered Neutron Beams At Dalat Research Reactor

    International Nuclear Information System (INIS)

    Tran Tuan Anh; Dang Lanh; Nguyen Canh Hai; Nguyen Xuan Hai; Pham Kien; Nguyen Thuy Nham; Pham Ngoc Son; Ho Huu Thang

    2007-01-01

    Determination of total neutron cross sections and average resonance parameters in the energy range from tens keV to hundreds keV is important for fast reactors calculations and designs because this energy range gives the most output of all neutron induced reactions in the spectrum of fast reactors. Besides, the total neutron cross section measurement is also one of the methods for determination of s, p and d-wave neutron strength functions. The purpose of this project is to develop a method for measurement of total neutron cross sections based on the neutron transmission technique using a He-3 counter. The average total neutron cross sections of 238 U were obtained from neutron transmission measurements on filtered neutron beams of 55 keV and 144 keV at the horizontal channel No.4 of the Dalat research reactor. The present results have been compared with the previous measurements, and the evaluated data from ENDF/B-6.8 library. (author)

  10. Assessment of bridge scour in the lower, middle, and upper Yangtze River estuary with riverbed sonar profiling techniques.

    Science.gov (United States)

    Zheng, Shuwei; Xu, Y Jun; Cheng, Heqin; Wang, Bo; Lu, Xuejun

    2017-12-12

    Riverbed scour of bridge piers can cause rapid loss in foundation strength, leading to sudden bridge collapse. This study used multi-beam echo sounders (Seabat 7125) to map riverbed surrounding the foundations of four major bridges in the lower, middle, and upper reaches of the 700-km Yangtze River Estuary (YRE) during June 2015 and September 2016. The high-resolution data were utilized to analyze the morphology of the bridge scour and the deformation of the wide-area riverbed (i.e., 5-18 km long and 1.3-8.3 km wide). In addition, previous bathymetric measurements collected in 1998, 2009, and 2013 were used to determine riverbed erosion and deposition at the bridge reaches. Our study shows that the scour depth surrounding the bridge foundations progressed up to 4.4-19.0 m in the YRE. Over the past 5-15 years, the total channel erosion in some river reaches was up to 15-17 m, possessing a threat to the bridge safety in the YRE. Tide cycles seemed to have resulted in significant variation in the scour morphology in the lower and middle YRE. In the lower YRE, the riverbed morphology displayed one long erosional ditch on both sides of the bridge foundations and a long-strip siltation area distributed upstream and downstream of the bridge foundations; in the middle YRE, the riverbed morphology only showed erosional morphology surrounding the bridge foundations. Large dunes caused deep cuts and steeper contours in the bridge scour. Furthermore, this study demonstrates that the high-resolution grid model formed by point cloud data of multi-beam echo sounders can clearly display the morphology of the bridge scour in terms of wide areas and that the sonar technique is a very useful tool in the assessment of bridge scours.

  11. Bubble Clouds and their Transport within the Surf Zone as Measured with a Distributed Array of Upward-Looking Sonars

    National Research Council Canada - National Science Library

    Dahl, Peter

    2000-01-01

    ... in the surf zone and the effects of these bubbles on acoustic propagation. This paper discusses data gathered by the Applied Physics Laboratory, University of Washington, using a set of four upward-looking sonars (frequency 240 kHz...

  12. Neuroglial Transmission

    DEFF Research Database (Denmark)

    Gundersen, Vidar; Storm-Mathisen, Jon; Bergersen, Linda Hildegard

    2015-01-01

    as a signaling substance recently shown to act on specific lactate receptors in the brain. Complementing neurotransmission at a synapse, neuroglial transmission often implies diffusion of the transmitter over a longer distance and concurs with the concept of volume transmission. Transmission from glia modulates...... synaptic neurotransmission based on energetic and other local conditions in a volume of tissue surrounding the individual synapse. Neuroglial transmission appears to contribute significantly to brain functions such as memory, as well as to prevalent neuropathologies....

  13. Improvement of air transport data and wall transmission/reflection data in the SKYSHINE code. (1) Calculation of line beam response function for gamma-ray skyshine analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Makoto [Visible Information Center, Tokai, Ibaraki (Japan); Harima, Yoshiko; Ishikawa, Satoshi [CRC Research Inst. Inc., Tokyo (Japan); Hirayama, Hideo [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Sakamoto, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan); Hayashi, Katsumi; Tayama, Ryuichi [Hitachi Engineering Co. Ltd., Ibaraki (Japan); Hayashida, Yoshihisa [Toshiba Corp., Yokohama, Kanagawa (Japan); Sato, Osamu [Mitsubishi Research Inst., Tokyo (Japan)

    2000-03-01

    The line-beam response functions (LBRFs) of a key component of a computationally simple gamma-ray skyshine analysis are generated using an electron-photon cascade Monte Carlo code EGS4. The LBRFs R(E{sub 0}, {phi}, x) are given with the air-kerma (Gy per photon), 7 photon source energies ranging from 0.5 to 10 MeV, for source-detector distances between 10 and 2,000 meters, and at 19 emission angles from 0 - 170 degrees, as measured from the source-detector axis. Especially, the values of R(E{sub 0}, {phi}=0.0 and 0.1, x) are extremely larger than the ones of LBRFs produced by the point kernel model or the COHORT code. The LBRF is accurately approximated by a four-parameter formula. Values of four parameters for the approximate LBRF are described by monotonic and smooth curves with respect to the energy E{sub 0} and the emitted angle {phi}. (author)

  14. Monitoring the US ATLAS Network Infrastructure with perfSONAR-PS

    CERN Document Server

    McKee, S; The ATLAS collaboration; Laurens, P; Severini, H; Wlodek, T; Wolff, S; Zurawski, J

    2012-01-01

    We will present our motivations for deploying and using the perfSONAR-PS Performance Toolkit at ATLAS sites in the United States and describe our experience in using it. This software creates a dedicated monitoring server, capable of collecting and performing a wide range of passive and active network measurements. Each independent instance is managed locally, but able to federate on a global scale; enabling a full view of the network infrastructure that spans domain boundaries. This information, available through web service interfaces, can easily be retrieved to create customized applications. USATLAS has developed a centralized “dashboard” offering network administrators, users, and decision makers the ability to see the performance of the network at a glance. The dashboard framework includes the ability to notify users (alarm) when problems are found, thus allowing rapid response to potential problems and making perfSONAR-PS crucial to the operation of our distributed computing infrastructure.

  15. A Spatial Reference Grid for Real-Time Autonomous Underwater Modeling using 3-D Sonar

    Energy Technology Data Exchange (ETDEWEB)

    Auran, P.G.

    1996-12-31

    The offshore industry has recognized the need for intelligent underwater robotic vehicles. This doctoral thesis deals with autonomous underwater vehicles (AUVs) and concentrates on a data representation for real-time image formation and analysis. Its main objective is to develop a 3-D image representation suitable for autonomous perception objectives underwater, assuming active sonar as the main sensor for perception. The main contributions are: (1) A dynamical image representation for 3-D range data, (2) A basic electronic circuit and software system for 3-D sonar sampling and amplitude thresholding, (3) A model for target reliability, (4) An efficient connected components algorithm for 3-D segmentation, (5) A method for extracting general 3-D geometrical representations from segmented echo clusters, (6) Experimental results of planar and curved target modeling. 142 refs., 120 figs., 10 tabs.

  16. Discrimination of Cylinders with Different Wall Thicknesses using Neural Networks and Simulated Dolphin Sonar Signals

    DEFF Research Database (Denmark)

    Andersen, Lars Nonboe; Au, Whitlow; Larsen, Jan

    1999-01-01

    This paper describes a method integrating neural networks into a system for recognizing underwater objects. The system is based on a combination of simulated dolphin sonar signals, simulated auditory filters and artificial neural networks. The system is tested on a cylinder wall thickness...... difference experiment and demonstrates high accuracy for small wall thickness differences. Results from the experiment are compared with results obtained by a false killer whale (pseudorca crassidens)....

  17. On Estimation Of The Orientation Of Mobile Robots Using Turning Functions And SONAR Information

    Directory of Open Access Journals (Sweden)

    Dorel AIORDACHIOAIE

    2003-12-01

    Full Text Available SONAR systems are widely used by some artificial objects, e.g. robots, and by animals, e.g. bats, for navigation and pattern recognition. The objective of this paper is to present a solution on the estimation of the orientation in the environment of mobile robots, in the context of navigation, using the turning function approach. The results are shown to be accurate and can be used further in the design of navigation strategies of mobile robots.

  18. A Study to Interpret the Biological Significance of Behavior Associated with 3S Experimental Sonar Exposures

    Science.gov (United States)

    2015-09-30

    species; 2.) quantitative comparison of behavior, and behavioral changes, during sonar presentation and playback of killer whale sounds across the 3S... foraging dives were pre-classified from the remaining dives first by determining a break-point depth in the depth versus duration relationship, and then...AIC point to divide dive depth versus duration relationships (Fig. 2). 50.8% of dives greater than 15m in depth were classified as foraging dives

  19. A micro-Doppler sonar for acoustic surveillance in sensor networks

    Science.gov (United States)

    Zhang, Zhaonian

    Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

  20. Multibeam sonar (DIDSON) assessment of American shad (Alosa sapidissima) approaching a hydroelectric dam

    Science.gov (United States)

    Grote, Ann B.; Bailey, Michael M.; Zydlewski, Joseph D.; Hightower, Joseph E.

    2014-01-01

    We investigated the fish community approaching the Veazie Dam on the Penobscot River, Maine, prior to implementation of a major dam removal and river restoration project. Multibeam sonar (dual-frequency identification sonar, DIDSON) surveys were conducted continuously at the fishway entrance from May to July in 2011. A 5% subsample of DIDSON data contained 43 793 fish targets, the majority of which were of Excellent (15.7%) or Good (73.01%) observation quality. Excellent quality DIDSON targets (n = 6876) were apportioned by species using a Bayesian mixture model based on four known fork length distributions (river herring (alewife,Alosa psuedoharengus, and blueback herring, Alosa aestivalis), American shad, Alosa sapidissima) and two size classes (one sea-winter and multi-sea-winter) of Atlantic salmon (Salmo salar). 76.2% of targets were assigned to the American shad distribution; Atlantic salmon accounted for 15.64%, and river herring 8.16% of observed targets. Shad-sized (99.0%) and salmon-sized (99.3%) targets approached the fishway almost exclusively during the day, whereas river herring-sized targets were observed both during the day (51.1%) and at night (48.9%). This approach demonstrates how multibeam sonar imaging can be used to evaluate community composition and species-specific movement patterns in systems where there is little overlap in the length distributions of target species.

  1. Recommendations for improved and coherent acquisition and processing of backscatter data from seafloor-mapping sonars

    Science.gov (United States)

    Lamarche, Geoffroy; Lurton, Xavier

    2018-06-01

    Multibeam echosounders are becoming widespread for the purposes of seafloor bathymetry mapping, but the acquisition and the use of seafloor backscatter measurements, acquired simultaneously with the bathymetric data, are still insufficiently understood, controlled and standardized. This presents an obstacle to well-accepted, standardized analysis and application by end users. The Marine Geological and Biological Habitat Mapping group (Geohab.org) has long recognized the need for better coherence and common agreement on acquisition, processing and interpretation of seafloor backscatter data, and established the Backscatter Working Group (BSWG) in May 2013. This paper presents an overview of this initiative, the mandate, structure and program of the working group, and a synopsis of the BSWG Guidelines and Recommendations to date. The paper includes (1) an overview of the current status in sensors and techniques available in seafloor backscatter data from multibeam sonars; (2) the presentation of the BSWG structure and results; (3) recommendations to operators, end-users, sonar manufacturers, and software developers using sonar backscatter for seafloor-mapping applications, for best practice methods and approaches for data acquisition and processing; and (4) a discussion on the development needs for future systems and data processing. We propose for the first time a nomenclature of backscatter processing levels that affords a means to accurately and efficiently describe the data processing status, and to facilitate comparisons of final products from various origins.

  2. Boundary layer structure observed by Shipborne Doppler Sonar in the Suez Canal zone

    Energy Technology Data Exchange (ETDEWEB)

    Fiocco, G. (Rome Univ. (Italy). Ist. di Fisica); Mastrantonio, G.; Ricotta, A. (Consiglio Nazionale delle Ricerche, Frascati (Italy). Lab. per il Plasma nello Spazio)

    Observations of the boundary layer with a monostatic Sonar and other instrumentation were carried out in the Suez canal zone in January and March 1979, from the Italian m.v. Salernum on its way to and from a GARP assignment. The Sonar was operated almost continuously throughout the passages. In addition to the intensity records, an off-line Doppler analysis involving the use of the fast Fourier transform of the digitized Sonar echoes has provided the vertical component w of the velocity. In general, because of efficient filtering and of the good quality of the data, a vertical profile of w has been determined for each transmitted pulse. During a prolonged stay in the Bitter lakes vertical profiles of temperature and humidity were also obtained by deploying a tethered balloon. Large temporal and spatial temperature contrasts exist in the canal zone due to the presence of the desert and of large and small bodies of water. The ensuring phenomenology during the time of observation was quite varied.

  3. Inversion of Side Scan Sonar Motion and Posture in Seabed Geomorphology

    Directory of Open Access Journals (Sweden)

    Tao Weiliang

    2017-08-01

    Full Text Available Side scan sonar measurement platform, affected by underwater environment and its own motion precision, inevitably has posture and motion disturbance, which greatly affects accuracy of geomorphic image formation. It is difficult to sensitively and accurately capture these underwater disturbances by relying on auxiliary navigation devices. In this paper, we propose a method to invert motion and posture information of the measurement platform by using the matching relation between the strip images. The inversion algorithm is the key link in the image mosaic frame of side scan sonar, and the acquired motion posture information can effectively improve seabed topography and plotting accuracy and stability. In this paper, we first analyze influence of platform motion and posture on side scan sonar mapping, and establish the correlation model between motion, posture information and strip image matching information. Then, based on the model, a reverse neural network is established. Based on input, output of neural network, design of and test data set, a motion posture inversion mechanism based on strip image matching information is established. Accuracy and validity of the algorithm are verified by the experimental results.

  4. PMHT Approach for Multi-Target Multi-Sensor Sonar Tracking in Clutter.

    Science.gov (United States)

    Li, Xiaohua; Li, Yaan; Yu, Jing; Chen, Xiao; Dai, Miao

    2015-11-06

    Multi-sensor sonar tracking has many advantages, such as the potential to reduce the overall measurement uncertainty and the possibility to hide the receiver. However, the use of multi-target multi-sensor sonar tracking is challenging because of the complexity of the underwater environment, especially the low target detection probability and extremely large number of false alarms caused by reverberation. In this work, to solve the problem of multi-target multi-sensor sonar tracking in the presence of clutter, a novel probabilistic multi-hypothesis tracker (PMHT) approach based on the extended Kalman filter (EKF) and unscented Kalman filter (UKF) is proposed. The PMHT can efficiently handle the unknown measurements-to-targets and measurements-to-transmitters data association ambiguity. The EKF and UKF are used to deal with the high degree of nonlinearity in the measurement model. The simulation results show that the proposed algorithm can improve the target tracking performance in a cluttered environment greatly, and its computational load is low.

  5. Transmission issues

    International Nuclear Information System (INIS)

    Bradford, J.; Wilson, L.; Thon, S.; Millar, N.

    2005-01-01

    This session on transmission issues focused on the role that transmission plays in electricity markets and the importance of getting the market structure right in terms of generation divestiture with buy back contracts, demand side responsive programs, transmission upgrades and long term contracts. The difficulties of distinguishing between market power and scarcity were examined along with some of the complications that ensue if transmission experiences congestion, as exemplified by the August 2003 blackout in eastern North America. The presentations described the best ways to handle transmission issues, and debated whether transmission should be deregulated or follow market forces. Issues of interconnections and reliability of connections were also debated along with the attempt to integrate renewables into the grid. Some presentations identified what new transmission must be built and what must be done to ensure that transmission gets built. The challenges and business opportunities for transmission in Alberta were discussed with reference to plans to invest in new infrastructure, where it is going outside of the province and how it works with other jurisdictions. Manitoba's Conawapa Hydro Project and its 2000 MW tie line to Ontario was also discussed. Some examples of non-optimal use of interconnections in Europe were also discussed in an effort to learn from these mistakes and avoid them in Canada. tabs., figs

  6. VIVITRON beam transport

    International Nuclear Information System (INIS)

    Nadji, A.

    1989-07-01

    The VIVITRON is a new 35 MV particle accelerator which presents a great number of innovations. One of the major problem is the beam transport in this electrostatic machine of 50 m length for ions with masses between 1 and 200. Our work consisted in the study of various experimental and theoretical aspects of the beam transport in Tandem accelerators from the ion source to the analysing magnet. Calculations of the beam optics were performed with a Strasbourg version of the computer code Transport. They allowed us to optimize the beam transport parameters of the VIVITRON elements. Special attention has been focused on the design of the charge state selector to be installed in the terminal of the new machine. Beam transmission measurements were carried out in the Strasbourg MP 10 Tandem accelerator for ions beams of masses between 1 and 127 and for terminal voltages from 9 to 15 MV. Partial and total transmissions were obtained and explanations of the beam losses were proposed in terms of the vacuum pressure and/or the optics of the beam accelerator system. The results have been extrapolated to the VIVITRON for which the best working conditions are now clearly defined [fr

  7. Enhanced echolocation via robust statistics and super-resolution of sonar images

    Science.gov (United States)

    Kim, Kio

    Echolocation is a process in which an animal uses acoustic signals to exchange information with environments. In a recent study, Neretti et al. have shown that the use of robust statistics can significantly improve the resiliency of echolocation against noise and enhance its accuracy by suppressing the development of sidelobes in the processing of an echo signal. In this research, the use of robust statistics is extended to problems in underwater explorations. The dissertation consists of two parts. Part I describes how robust statistics can enhance the identification of target objects, which in this case are cylindrical containers filled with four different liquids. Particularly, this work employs a variation of an existing robust estimator called an L-estimator, which was first suggested by Koenker and Bassett. As pointed out by Au et al.; a 'highlight interval' is an important feature, and it is closely related with many other important features that are known to be crucial for dolphin echolocation. A varied L-estimator described in this text is used to enhance the detection of highlight intervals, which eventually leads to a successful classification of echo signals. Part II extends the problem into 2 dimensions. Thanks to the advances in material and computer technology, various sonar imaging modalities are available on the market. By registering acoustic images from such video sequences, one can extract more information on the region of interest. Computer vision and image processing allowed application of robust statistics to the acoustic images produced by forward looking sonar systems, such as Dual-frequency Identification Sonar and ProViewer. The first use of robust statistics for sonar image enhancement in this text is in image registration. Random Sampling Consensus (RANSAC) is widely used for image registration. The registration algorithm using RANSAC is optimized for sonar image registration, and the performance is studied. The second use of robust

  8. SONAR: A high-throughput pipeline for inferring antibody ontogenies from longitudinal sequencing of B cell transcripts

    Directory of Open Access Journals (Sweden)

    Chaim A Schramm

    2016-09-01

    Full Text Available The rapid advance of massively parallel or next-generation sequencing technologies has made possible the characterization of B cell receptor repertoires in ever greater detail, leading to a proliferation of software tools for processing and annotating this data. Of especial interest, however, is the capability to track the development of specific antibody lineages across time, which remains beyond the scope of most current programs. We have previously reported on the use of techniques such as inter- and intra-donor analysis and CDR3 tracing to identify transcripts related to an antibody of interest. Here, we present Software for the Ontogenic aNalysis of Antibody Repertoires (SONAR, capable of automating both general repertoire analysis and specialized techniques for investigating specific lineages. SONAR annotates next-generation sequencing data, identifies transcripts in a lineage of interest, and tracks lineage development across multiple time points. SONAR also generates figures, such as identity-divergence plots and longitudinal phylogenetic birthday trees, and provides interfaces to other programs such as DNAML and BEAST. SONAR can be downloaded as a ready-to-run Docker image or manually installed on a local machine. In the latter case, it can also be configured to take advantage of a high-performance computing cluster for the most computationally intensive steps, if available. In summary, this software provides a useful new tool for the processing of large next-generation sequencing datasets and the ontogenic analysis of neutralizing antibody lineages. SONAR can be found at https://github.com/scharch/SONAR and the Docker image can be obtained from https://hub.docker.com/r/scharch/sonar/.

  9. SONAR: A High-Throughput Pipeline for Inferring Antibody Ontogenies from Longitudinal Sequencing of B Cell Transcripts.

    Science.gov (United States)

    Schramm, Chaim A; Sheng, Zizhang; Zhang, Zhenhai; Mascola, John R; Kwong, Peter D; Shapiro, Lawrence

    2016-01-01

    The rapid advance of massively parallel or next-generation sequencing technologies has made possible the characterization of B cell receptor repertoires in ever greater detail, and these developments have triggered a proliferation of software tools for processing and annotating these data. Of especial interest, however, is the capability to track the development of specific antibody lineages across time, which remains beyond the scope of most current programs. We have previously reported on the use of techniques such as inter- and intradonor analysis and CDR3 tracing to identify transcripts related to an antibody of interest. Here, we present Software for the Ontogenic aNalysis of Antibody Repertoires (SONAR), capable of automating both general repertoire analysis and specialized techniques for investigating specific lineages. SONAR annotates next-generation sequencing data, identifies transcripts in a lineage of interest, and tracks lineage development across multiple time points. SONAR also generates figures, such as identity-divergence plots and longitudinal phylogenetic "birthday" trees, and provides interfaces to other programs such as DNAML and BEAST. SONAR can be downloaded as a ready-to-run Docker image or manually installed on a local machine. In the latter case, it can also be configured to take advantage of a high-performance computing cluster for the most computationally intensive steps, if available. In summary, this software provides a useful new tool for the processing of large next-generation sequencing datasets and the ontogenic analysis of neutralizing antibody lineages. SONAR can be found at https://github.com/scharch/SONAR, and the Docker image can be obtained from https://hub.docker.com/r/scharch/sonar/.

  10. Transmission eigenvalues

    Science.gov (United States)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  11. Beam-beam phenomenology

    International Nuclear Information System (INIS)

    Teng, L.C.

    1980-01-01

    In colliding beam storage rings the beam collision regions are generally so short that the beam-beam interaction can be considered as a series of evenly spaced non-linear kicks superimposed on otherwise stable linear oscillations. Most of the numerical studies on computers were carried out in just this manner. But for some reason this model has not been extensively employed in analytical studies. This is perhaps because all analytical work has so far been done by mathematicians pursuing general transcendental features of non-linear mechanics for whom this specific model of the specific system of colliding beams is too parochial and too repugnantly physical. Be that as it may, this model is of direct interest to accelerator physicists and is amenable to (1) further simplification, (2) physical approximation, and (3) solution by analogy to known phenomena

  12. Transmission efficiency measurement at the FNAL 4-rod RFQ

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, J. P. [Fermilab; Garcia, F. G. [Fermilab; Ostiguy, J. F. [Fermilab; Saini, A. [Fermilab; Zwaska, R. [Fermilab; Mustapha, B. [Argonne; Ostroumov, P. [Argonne

    2014-12-01

    This paper presents measurements of the beam transmission performed on the 4-rod RFQ currently under operation at Fermilab. The beam current has been measured at the RFQ exit as a function of the magnetic field strength in the two LEBT solenoids. This measurement is compared with scans performed on the FermiGrid with the beam dynamics code TRACK. A particular attention is given to the impact, on the RFQ beam transmission, of the space-charge neutralization in the LEBT.

  13. Quantifying Transmission.

    Science.gov (United States)

    Woolhouse, Mark

    2017-07-01

    Transmissibility is the defining characteristic of infectious diseases. Quantifying transmission matters for understanding infectious disease epidemiology and designing evidence-based disease control programs. Tracing individual transmission events can be achieved by epidemiological investigation coupled with pathogen typing or genome sequencing. Individual infectiousness can be estimated by measuring pathogen loads, but few studies have directly estimated the ability of infected hosts to transmit to uninfected hosts. Individuals' opportunities to transmit infection are dependent on behavioral and other risk factors relevant given the transmission route of the pathogen concerned. Transmission at the population level can be quantified through knowledge of risk factors in the population or phylogeographic analysis of pathogen sequence data. Mathematical model-based approaches require estimation of the per capita transmission rate and basic reproduction number, obtained by fitting models to case data and/or analysis of pathogen sequence data. Heterogeneities in infectiousness, contact behavior, and susceptibility can have substantial effects on the epidemiology of an infectious disease, so estimates of only mean values may be insufficient. For some pathogens, super-shedders (infected individuals who are highly infectious) and super-spreaders (individuals with more opportunities to transmit infection) may be important. Future work on quantifying transmission should involve integrated analyses of multiple data sources.

  14. Modification of beam lines at VEC

    Energy Technology Data Exchange (ETDEWEB)

    Shoor, Bivas; Chakraborty, P S; Mallik, C; Bhandari, R K [Variable Energy Cyclotron Centre, Calcutta (India)

    1997-12-01

    From the experience of light ion beam transportation through the Variable Energy Cyclotron beam line, it was observed that the beam line performance has to be improved in view of heavy ion acceleration program at the centre. The aim of this work was to study the feasibility of reducing the number of operational parameters without hampering the beam transmission and at the same time, to improve the vacuum of the beam line by reducing the hardware 2 refs., 1 fig.

  15. Force transmissibility versus displacement transmissibility

    Science.gov (United States)

    Lage, Y. E.; Neves, M. M.; Maia, N. M. M.; Tcherniak, D.

    2014-10-01

    It is well-known that when a single-degree-of-freedom (sdof) system is excited by a continuous motion of the foundation, the force transmissibility, relating the force transmitted to the foundation to the applied force, equals the displacement transmissibility. Recent developments in the generalization of the transmissibility to multiple-degree-of-freedom (mdof) systems have shown that similar simple and direct relations between both types of transmissibility do not appear naturally from the definitions, as happens in the sdof case. In this paper, the authors present their studies on the conditions under which it is possible to establish a relation between force transmissibility and displacement transmissibility for mdof systems. As far as the authors are aware, such a relation is not currently found in the literature, which is justified by being based on recent developments in the transmissibility concept for mdof systems. Indeed, it does not appear naturally, but the authors observed that the needed link is present when the displacement transmissibility is obtained between the same coordinates where the applied and reaction forces are considered in the force transmissibility case; this implies that the boundary conditions are not exactly the same and instead follow some rules. This work presents a formal derivation of the explicit relation between the force and displacement transmissibilities for mdof systems, and discusses its potential and limitations. The authors show that it is possible to obtain the displacement transmissibility from measured forces, and the force transmissibility from measured displacements, opening new perspectives, for example, in the identification of applied or transmitted forces. With this novel relation, it becomes possible, for example, to estimate the force transmissibility matrix with the structure off its supports, in free boundary conditions, and without measuring the forces. As far as force identification is concerned, this

  16. Data transmission

    National Research Council Canada - National Science Library

    Tugal, Dogan A; Tugal, Osman

    1989-01-01

    This updated second edition provides working answers to today's critical questions about designing and managing all types of data transmission systems and features a new chapter on local area networks (LANs...

  17. Directionality of sperm whale sonar clicks and its relation to piston radiation theory

    DEFF Research Database (Denmark)

    Beedholm, K.; Møhl, Bertel

    2006-01-01

    This paper investigates the applicability to sperm whales of the theory of sound radiating from a piston. The theory is applied to a physical model and to a series of sperm whale clicks. Results show that wave forms of off-axis signals can be reproduced by convolving an on-axis signal...... with the spatial impulse response of a piston. The angle of a recorded click can be estimated as the angle producing the spatial impulse response that gives the best match with the observation when convolved with the on-axis wave form. It is concluded that piston theory applies to sperm whale sonar click emission....

  18. Automatic Target Recognition in Synthetic Aperture Sonar Images Based on Geometrical Feature Extraction

    Directory of Open Access Journals (Sweden)

    J. Del Rio Vera

    2009-01-01

    Full Text Available This paper presents a new supervised classification approach for automated target recognition (ATR in SAS images. The recognition procedure starts with a novel segmentation stage based on the Hilbert transform. A number of geometrical features are then extracted and used to classify observed objects against a previously compiled database of target and non-target features. The proposed approach has been tested on a set of 1528 simulated images created by the NURC SIGMAS sonar model, achieving up to 95% classification accuracy.

  19. Recreational-Grade Sidescan Sonar: Transforming a Low-Cost Leisure Gadget into a High Resolution Riverbed Remote Sensing Tool

    Science.gov (United States)

    Hamill, D. D.; Buscombe, D.; Wheaton, J. M.; Wilcock, P. R.

    2016-12-01

    The size and spatial organization of bed material, bed texture, is a fundamental physical attribute of lotic ecosystems. Traditional methods to map bed texture (such as physical samples and underwater video) are limited by low spatial coverage, and poor precision in positioning. Recreational grade sidescan sonar systems now offer the possibility of imaging submerged riverbed sediments at coverages and resolutions sufficient to identify subtle changes in bed texture, in any navigable body of water, with minimal cost, expertise in sonar, or logistical effort, thereby facilitating the democratization of acoustic imaging of benthic environments, to support ecohydrological studies in shallow water, not subject to the rigors of hydrographic standards, nor the preserve of hydroacoustic expertise and proprietary hydrographic industry software. We investigate the possibility of using recreational grade sidescan sonar for sedimentary change detection using a case study of repeat sidescan imaging of mixed sand-gravel-rock riverbeds in a debris-fan dominated canyon river, at a coverage and resolution that meets the objectives of studies of the effects of changing bed substrates on salmonid spawning. A repeat substrate mapping analysis on data collected between 2012 and 2015 on the Colorado River in Glen, Marble, and Grand Canyons will be presented. A detailed method has been developed to interpret and analyze non-survey-grade sidescan sonar data, encoded within an open source software tool developed by the authors. An automated technique to quantify bed texture directly from sidescan sonar imagery is tested against bed sediment observations from underwater video and multibeam sonar. Predictive relationships between known bed sediment observations and bed texture metrics could provide an objective means to quantify bed textures and to relate changes in bed texture to biological components of an aquatic ecosystem, at high temporal frequency, and with minimal logistical effort

  20. Efficient electron beam deposition for repetitively pulsed krypton fluoride lasers

    International Nuclear Information System (INIS)

    Hegeler, F.; Myers, M.C.; Friedman, M.; Sethian, J.D.; Swanekamp, S.B.; Rose, D.V.; Welch, D.R.

    2002-01-01

    We have demonstrated that we can significantly increase the electron beam transmission efficiency through a pressure foil structure (hibachi) by segmenting the beam into strips to miss the hibachi support ribs. In order to increase the electron beam transmission, the cathode strips are adjusted to compensate for beam rotation and pinching. The beam propagation through the hibachi has been both measured and simulated with 1-D and 3-D codes

  1. Wall-corner classification using sonar: a new approach based on geometric features.

    Science.gov (United States)

    Martínez, Milagros; Benet, Ginés

    2010-01-01

    Ultrasonic signals coming from rotary sonar sensors in a robot gives us several features about the environment. This enables us to locate and classify the objects in the scenario of the robot. Each object and reflector produces a series of peaks in the amplitude of the signal. The radial and angular position of the sonar sensor gives information about location and their amplitudes offer information about the nature of the surface. Early works showed that the amplitude can be modeled and used to classify objects with very good results at short distances-80% average success in classifying both walls and corners at distances less than 1.5 m. In this paper, a new set of geometric features derived from the amplitude analysis of the echo is presented. These features constitute a set of characteristics that can be used to improve the results of classification at distances from 1.5 m to 4 m. Also, a comparative study on classification algorithms widely used in pattern recognition techniques has been carried out for sensor distances ranging between 0.5 to 4 m, and with incidence angles ranging between 20° to 70°. Experimental results show an enhancement on the success in classification rates when these geometric features are considered.

  2. An Adaptive Cultural Algorithm with Improved Quantum-behaved Particle Swarm Optimization for Sonar Image Detection.

    Science.gov (United States)

    Wang, Xingmei; Hao, Wenqian; Li, Qiming

    2017-12-18

    This paper proposes an adaptive cultural algorithm with improved quantum-behaved particle swarm optimization (ACA-IQPSO) to detect the underwater sonar image. In the population space, to improve searching ability of particles, iterative times and the fitness value of particles are regarded as factors to adaptively adjust the contraction-expansion coefficient of the quantum-behaved particle swarm optimization algorithm (QPSO). The improved quantum-behaved particle swarm optimization algorithm (IQPSO) can make particles adjust their behaviours according to their quality. In the belief space, a new update strategy is adopted to update cultural individuals according to the idea of the update strategy in shuffled frog leaping algorithm (SFLA). Moreover, to enhance the utilization of information in the population space and belief space, accept function and influence function are redesigned in the new communication protocol. The experimental results show that ACA-IQPSO can obtain good clustering centres according to the grey distribution information of underwater sonar images, and accurately complete underwater objects detection. Compared with other algorithms, the proposed ACA-IQPSO has good effectiveness, excellent adaptability, a powerful searching ability and high convergence efficiency. Meanwhile, the experimental results of the benchmark functions can further demonstrate that the proposed ACA-IQPSO has better searching ability, convergence efficiency and stability.

  3. High frequency sonar variability in littoral environments: Irregular particles and bubbles

    Science.gov (United States)

    Richards, Simon D.; Leighton, Timothy G.; White, Paul R.

    2002-11-01

    Littoral environments may be characterized by high concentrations of suspended particles. Such suspensions contribute to attenuation through visco-inertial absorption and scattering and may therefore be partially responsible for the observed variability in high frequency sonar performance in littoral environments. Microbubbles which are prevalent in littoral waters also contribute to volume attenuation through radiation, viscous and thermal damping and cause dispersion. The attenuation due to a polydisperse suspension of particles with depth-dependent concentration has been included in a sonar model. The effects of a depth-dependent, polydisperse population of microbubbles on attenuation, sound speed and volume reverberation are also included. Marine suspensions are characterized by nonspherical particles, often plate-like clay particles. Measurements of absorption in dilute suspensions of nonspherical particles have shown disagreement with predictions of spherical particle models. These measurements have been reanalyzed using three techniques for particle sizing: laser diffraction, gravitational sedimentation, and centrifugal sedimentation, highlighting the difficulty of characterizing polydisperse suspensions of irregular particles. The measurements have been compared with predictions of a model for suspensions of oblate spheroids. Excellent agreement is obtained between this model and the measurements for kaolin particles, without requiring any a priori knowledge of the measurements.

  4. Electrical transmission

    Energy Technology Data Exchange (ETDEWEB)

    Sayers, D P

    1960-05-01

    After briefly tracing the history of electricity transmission, trends in high voltage transmission and experiments being conducted on 650 kV are discussed. 5000 miles of the U.K. grid are operated at 132 kV and 1000 at 275 kV, ultimately to provide a super grid at 380 kV. Problems are insulation, radio interference and the cost of underground lines (16 times that of overhead lines). Also considered are the economics of the grid as a means of transporting energy and as a means of spreading the peak load over the power stations in the most efficient manner. Finally, the question of amenities is discussed.

  5. Acoustic beam control in biomimetic projector via velocity gradient

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xiaowei; Dong, Erqian; Song, Zhongchang [Key Laboratory of Underwater Acoustic Communication and Marine Information Technology of the Ministry of Education, Xiamen University, Xiamen 361005 (China); Zhang, Yu, E-mail: yuzhang@xmu.edu.cn, E-mail: dzk@psu.edu; Tang, Liguo [Key Laboratory of Underwater Acoustic Communication and Marine Information Technology of the Ministry of Education, Xiamen University, Xiamen 361005 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005 (China); Cao, Wenwu, E-mail: yuzhang@xmu.edu.cn, E-mail: dzk@psu.edu [Department of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Li, Songhai [Sanya Key Laboratory of Marin Mammal and Marine Bioacoustics, Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Science, Sanya 57200 (China); Zhang, Sai [Faculty of Science, Jiangsu University, Zhenjiang 212013 (China)

    2016-07-04

    A biomimetic projector (BioP) based on computerized tomography of pygmy sperm whale's biosonar system has been designed using gradient-index (GRIN) material. The directivity of this BioP device was investigated as function of frequency and the velocity gradient of the GRIN material. A strong beam control over a broad bandwidth at the subwavelength scale has been achieved. Compared with a bare subwavelength source, the main lobe pressure of the BioP is about five times as high and the angular resolution is one order of magnitude better. Our results indicate that this BioP has excellent application potential in miniaturized underwater sonars.

  6. Beam position monitor sensitivity for low-β beams

    International Nuclear Information System (INIS)

    Shafer, R.E.

    1993-01-01

    At low velocities, the EM field of a particle in a conducting beam tube is no longer a TEM wave, but has a finite longitudinal extent. The net effect of this is to reduce the coupling of the high-frequency Fourier components of the beam current to BPM (beam position monitor) electrodes, which modifies the BPM sensitivity to beam displacement. This effect is especially pronounced for high-frequency, large-aperture pickups used for low-β beams. Non-interceptive beam position monitors used in conjunction with high frequency RFQ (radio-frequency-quadrupole) and DTL (drift-tube-linac) accelerators fall into this category. When testing a BPM with a thin wire excited with either pulses or high-frequency sinusoidal currents, the EM wave represents the principal (TEM) mode in a coaxial transmission line, which is equivalent to a highly relativistic (β = 1) beam. Thus wire measurements are not suitable for simulating slow particle beams in high bandwidth diagnostic devices that couple to the image currents in the beam tube wall. Attempts to load the tin wire either capacitively or inductively to slow the EM wave down have met with limited success. In general, the equations used to represent the 2-D response of cylindrical-geometry BPMs to charged-particle beams make several assumptions: (1) the BPM electrodes are flush with and grounded to the surface of the conducting beam tube; (2) the beam is a line source (pencil beam); (3) the longitudinal extent of the EM field of a beam particle at the beam tube wall is zero, corresponding to a highly relativistic beam. The purpose of this paper is to make some quantitative estimates of the corrections to the conventional approximations when a BPM is used to measure the position of low velocity (low-β) beams

  7. On the design and construction of drifting-mine test targets for sonar, radar and electro-optical detection experiments

    NARCIS (Netherlands)

    Dol, H.S.

    2014-01-01

    The timely detection of small hazardous objects at the sea surface, such as drifting mines, is challenging for ship-mounted sensor systems, both for underwater sensor systems like sonar and above-water sensor systems like radar and electro-optics (lidar, infrared/visual cameras). This is due to the

  8. Olympic Coast National Marine Sanctuary - mos122_0702.tif - Side scan sonar mosaic from survey effort 122_0702.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (15-35 m water depths) was mosaiced from acoustic data collected in 2007 aboard the R/V Tatoosh. A Klein System 3000...

  9. Analysis of a new unidimensional model and lateral vibrations of 1-3 piezocomposite side scan sonar array

    CSIR Research Space (South Africa)

    Shatalov, MY

    2006-01-01

    Full Text Available . Lamb modes of the 1-3 piezocomposites are investigated in term of the Certon-Patat membrane model by means of direct variational method application. A new design of a 1-3 piezocomposite side scan SONAR array is considered. An implementation of the array...

  10. Passive synthetic aperture sonar techniques in combination with tow ship noise canceling: application to a triplet towed array

    NARCIS (Netherlands)

    Colin, M.E.G.D.; Groen, J.

    2002-01-01

    An important issue in research on passive ASW operations is improvement in signal-to-noise ratio (SNR) and bearing resolution for targets emitting low frequency signals. One of the techniques believed to improve these characteristics is Synthetic Aperture Sonar (SAS). The method is based on the

  11. Severity of Expert-Identified Behavioural Responses of Humpback Whale, Minke Whale, and Northern Bottlenose Whale to Naval Sonar

    NARCIS (Netherlands)

    Sivle, L.D.; Kvadsheim, P.H.; Cure, C.; Isojunno, S.; Wensveen, P.J.; Lam, F.P.A.; Visser, F.; Kleivane, L.; Tyack, P.L.; Harris, C.M.; Miller, P.J.O.

    2015-01-01

    Controlled exposure experiments using 1 to2 kHz sonar signals were conducted with 11 humpback whales (Megaptera novaeangliae), one minke whale (Balaenoptera acutorostrata), and one northern bottlenose whale (Hyperoodon ampullatus) during three field trials from 2011 to 2013. Ship approaches without

  12. Olympic Coast National Marine Sanctuary - mos120_0602b - Side scan sonar mosaic from survey effort 120_0602

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (70-90 m water depths) was mosaiced from acoustic data collected in 2006 aboard the R/V Tatoosh. A Klein System 3000...

  13. Olympic Coast National Marine Sanctuary - mos120_0602a - Side scan sonar mosaic from survey effort 120_0602

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (35-55 m water depths) was mosaiced from acoustic data collected in 2006 aboard the R/V Tatoosh. A Klein System 3000...

  14. Dose-response relationships for the onset of avoidance of sonar by free-ranging killer whales

    NARCIS (Netherlands)

    Miller, P.J.O.; Antunes, R.N.; Wensveen, P.J.; Samarra, F.I.P.; Alves, A.C.; Tyack, P.L.; Kvadsheim, P.H.; Kleivane, L.; Lam, F.P.A.; Ainslie, M.A.; Thomas, L.

    2014-01-01

    Eight experimentally controlled exposures to 1−2 kHz or 6−7 kHz sonar signals were conducted with four killer whale groups. The source level and proximity of the source were increased during each exposure in order to reveal response thresholds. Detailed inspection of movements during each exposure

  15. Coherent beam-beam effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1992-01-01

    There are two physical pictures that describe the beam-beam interaction in a storage ring collider: The weak-strong and the strong-strong pictures. Both pictures play a role in determining the beam-beam behavior. This review addresses only the strong-strong picture. The corresponding beam dynamical effects are referred to as the coherent beam-beam effects. Some basic knowledge of the weak-strong picture is assumed. To be specific, two beams of opposite charges are considered. (orig.)

  16. Algorithms and data structures for automated change detection and classification of sidescan sonar imagery

    Science.gov (United States)

    Gendron, Marlin Lee

    During Mine Warfare (MIW) operations, MIW analysts perform change detection by visually comparing historical sidescan sonar imagery (SSI) collected by a sidescan sonar with recently collected SSI in an attempt to identify objects (which might be explosive mines) placed at sea since the last time the area was surveyed. This dissertation presents a data structure and three algorithms, developed by the author, that are part of an automated change detection and classification (ACDC) system. MIW analysts at the Naval Oceanographic Office, to reduce the amount of time to perform change detection, are currently using ACDC. The dissertation introductory chapter gives background information on change detection, ACDC, and describes how SSI is produced from raw sonar data. Chapter 2 presents the author's Geospatial Bitmap (GB) data structure, which is capable of storing information geographically and is utilized by the three algorithms. This chapter shows that a GB data structure used in a polygon-smoothing algorithm ran between 1.3--48.4x faster than a sparse matrix data structure. Chapter 3 describes the GB clustering algorithm, which is the author's repeatable, order-independent method for clustering. Results from tests performed in this chapter show that the time to cluster a set of points is not affected by the distribution or the order of the points. In Chapter 4, the author presents his real-time computer-aided detection (CAD) algorithm that automatically detects mine-like objects on the seafloor in SSI. The author ran his GB-based CAD algorithm on real SSI data, and results of these tests indicate that his real-time CAD algorithm performs comparably to or better than other non-real-time CAD algorithms. The author presents his computer-aided search (CAS) algorithm in Chapter 5. CAS helps MIW analysts locate mine-like features that are geospatially close to previously detected features. A comparison between the CAS and a great circle distance algorithm shows that the

  17. Ecosystem scale acoustic sensing reveals humpback whale behavior synchronous with herring spawning processes and re-evaluation finds no effect of sonar on humpback song occurrence in the Gulf of Maine in fall 2006.

    Directory of Open Access Journals (Sweden)

    Zheng Gong

    Full Text Available We show that humpback-whale vocalization behavior is synchronous with peak annual Atlantic herring spawning processes in the Gulf of Maine. With a passive, wide-aperture, densely-sampled, coherent hydrophone array towed north of Georges Bank in a Fall 2006 Ocean Acoustic Waveguide Remote Sensing (OAWRS experiment, vocalizing whales could be instantaneously detected and localized over most of the Gulf of Maine ecosystem in a roughly 400-km diameter area by introducing array gain, of 18 dB, orders of magnitude higher than previously available in acoustic whale sensing. With humpback-whale vocalizations consistently recorded at roughly 2000/day, we show that vocalizing humpbacks (i were overwhelmingly distributed along the northern flank of Georges Bank, coinciding with the peak spawning time and location of Atlantic herring, and (ii their overall vocalization behavior was strongly diurnal, synchronous with the formation of large nocturnal herring shoals, with a call rate roughly ten-times higher at night than during the day. Humpback-whale vocalizations were comprised of (1 highly diurnal non-song calls, suited to hunting and feeding behavior, and (2 songs, which had constant occurrence rate over a diurnal cycle, invariant to diurnal herring shoaling. Before and during OAWRS survey transmissions: (a no vocalizing whales were found at Stellwagen Bank, which had negligible herring populations, and (b a constant humpback-whale song occurrence rate indicates the transmissions had no effect on humpback song. These measurements contradict the conclusions of Risch et al. Our analysis indicates that (a the song occurrence variation reported in Risch et al. is consistent with natural causes other than sonar, (b the reducing change in song reported in Risch et al. occurred days before the sonar survey began, and (c the Risch et al. method lacks the statistical significance to draw the conclusions of Risch et al. because it has a 98-100% false-positive rate

  18. Using data crawlers and semantic Web to build financial XBRL data generators: the SONAR extension approach.

    Science.gov (United States)

    Rodríguez-García, Miguel Ángel; Rodríguez-González, Alejandro; Colomo-Palacios, Ricardo; Valencia-García, Rafael; Gómez-Berbís, Juan Miguel; García-Sánchez, Francisco

    2014-01-01

    Precise, reliable and real-time financial information is critical for added-value financial services after the economic turmoil from which markets are still struggling to recover. Since the Web has become the most significant data source, intelligent crawlers based on Semantic Technologies have become trailblazers in the search of knowledge combining natural language processing and ontology engineering techniques. In this paper, we present the SONAR extension approach, which will leverage the potential of knowledge representation by extracting, managing, and turning scarce and disperse financial information into well-classified, structured, and widely used XBRL format-oriented knowledge, strongly supported by a proof-of-concept implementation and a thorough evaluation of the benefits of the approach.

  19. Monitoring the US ATLAS Network Infrastructure with perfSONAR-PS

    CERN Document Server

    McKee, S; The ATLAS collaboration; Laurens, P; Severini, H; Wlodek, T; Wolff, S; Zurawski, J

    2012-01-01

    Global scientific collaborations, such as ATLAS, continue to push the network requirements envelope. Data movement in this collaboration is routinely including the regular exchange of petabytes of datasets between the collection and analysis facilities in the coming years. These requirements place a high emphasis on networks functioning at peak efficiency and availability; the lack thereof could mean critical delays in the overall scientific progress of distributed data-intensive experiments like ATLAS. Network operations staff routinely must deal with problems deep in the infrastructure; this may be as benign as replacing a failing piece of equipment, or as complex as dealing with a multidomain path that is experiencing data loss. In either case, it is crucial that effective monitoring and performance analysis tools are available to ease the burden of management. We will report on our experiences deploying and using the perfSONAR-PS Performance Toolkit[8] at ATLAS sites in the United States. This software cr...

  20. Seafloor identification in sonar imagery via simulations of Helmholtz equations and discrete optimization

    Science.gov (United States)

    Engquist, Björn; Frederick, Christina; Huynh, Quyen; Zhou, Haomin

    2017-06-01

    We present a multiscale approach for identifying features in ocean beds by solving inverse problems in high frequency seafloor acoustics. The setting is based on Sound Navigation And Ranging (SONAR) imaging used in scientific, commercial, and military applications. The forward model incorporates multiscale simulations, by coupling Helmholtz equations and geometrical optics for a wide range of spatial scales in the seafloor geometry. This allows for detailed recovery of seafloor parameters including material type. Simulated backscattered data is generated using numerical microlocal analysis techniques. In order to lower the computational cost of the large-scale simulations in the inversion process, we take advantage of a pre-computed library of representative acoustic responses from various seafloor parameterizations.

  1. Using Data Crawlers and Semantic Web to Build Financial XBRL Data Generators: The SONAR Extension Approach

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Rodríguez-García

    2014-01-01

    Full Text Available Precise, reliable and real-time financial information is critical for added-value financial services after the economic turmoil from which markets are still struggling to recover. Since the Web has become the most significant data source, intelligent crawlers based on Semantic Technologies have become trailblazers in the search of knowledge combining natural language processing and ontology engineering techniques. In this paper, we present the SONAR extension approach, which will leverage the potential of knowledge representation by extracting, managing, and turning scarce and disperse financial information into well-classified, structured, and widely used XBRL format-oriented knowledge, strongly supported by a proof-of-concept implementation and a thorough evaluation of the benefits of the approach.

  2. Side-Scan Sonar Image Mosaic Using Couple Feature Points with Constraint of Track Line Positions

    Directory of Open Access Journals (Sweden)

    Jianhu Zhao

    2018-06-01

    Full Text Available To obtain large-scale seabed surface image, this paper proposes a side-scan sonar (SSS image mosaic method using couple feature points (CFPs with constraint of track line positions. The SSS geocoded images are firstly used to form a coarsely mosaicked one and the overlapping areas between adjacent strip images can be determined based on geographic information. Inside the overlapping areas, the feature point (FP detection and registration operation are adopted for both strips. According to the detected CFPs and track line positions, an adjustment model is established to accommodate complex local distortions as well as ensure the global stability. This proposed method effectively solves the problem of target ghosting or dislocation and no accumulated errors arise in the mosaicking process. Experimental results show that the finally mosaicked image correctly reflects the object distribution, which is meaningful for understanding and interpreting seabed topography.

  3. New sidescan sonar and gravity evidence that the Nova-Canton Trough is a fracture zone

    Science.gov (United States)

    Joseph, Devorah; Taylor, Brian; Shor, Alexander N.

    1992-05-01

    A 1990 sidescan sonar survey in the eastern region of the Nova-Canton Trough mapped 138°-striking abyssal-hill fabric trending into 70°-striking trough structures. The location and angle of intersection of the abyssal hills with the eastern Nova-Canton Trough effectively disprove a spreading-center origin of this feature. Free-air gravity anomalies derived from satellite altimetry data show continuity, across the Line Islands, of the Nova-Canton Trough with the Clipperton Fracture Zone. The Canton-Clipperton trend is copolar, about a pole at 30°S, 152°W, with other coeval Pacific-Farallon fracture-zone segments, from the Pau to Marquesas fracture zones. This copolarity leads us to postulate a Pacific-Farallon spreading pattern for the magnetic quiet zone region north and east of the Manihiki Plateau, with the Nova-Canton Trough originating as a transform fault in this system.

  4. Using Data Crawlers and Semantic Web to Build Financial XBRL Data Generators: The SONAR Extension Approach

    Science.gov (United States)

    Rodríguez-García, Miguel Ángel; Rodríguez-González, Alejandro; Valencia-García, Rafael; Gómez-Berbís, Juan Miguel

    2014-01-01

    Precise, reliable and real-time financial information is critical for added-value financial services after the economic turmoil from which markets are still struggling to recover. Since the Web has become the most significant data source, intelligent crawlers based on Semantic Technologies have become trailblazers in the search of knowledge combining natural language processing and ontology engineering techniques. In this paper, we present the SONAR extension approach, which will leverage the potential of knowledge representation by extracting, managing, and turning scarce and disperse financial information into well-classified, structured, and widely used XBRL format-oriented knowledge, strongly supported by a proof-of-concept implementation and a thorough evaluation of the benefits of the approach. PMID:24587726

  5. Experiences from using Autonomous Underwater Vehicles and Synthetic Aperture Sonar for Sediment and Habitat Mapping

    Science.gov (United States)

    Thorsnes, T.; Bjarnadóttir, L. R.

    2017-12-01

    Emerging platforms and tools like autonomous underwater vehicles and synthetic aperture sonars provide interesting opportunities for making seabed mapping more efficient and precise. Sediment grain-size maps are an important product in their own right and a key input for habitat and biotope maps. National and regional mapping programmes are tasked with mapping large areas, and survey efficiency, data quality, and resulting map confidence are important considerations when selecting the mapping strategy. Since 2005, c. 175,000 square kilometres of the Norwegian continental shelf and continental slope has been mapped with respect to sediments, habitats and biodiversity, and pollution under the MAREANO programme (www.mareano.no). At present the sediment mapping is based on a combination of ship-borne multibeam bathymetry and backscatter, visual documentation using a towed video platform, and grab sampling. We have now tested a new approach, using an Autonomous Underwater Vehicle (AUV) as the survey platform for the collection of acoustic data (Synthetic Aperture Sonar (SAS), EM2040 bathymetry and backscatter) and visual data (still images using a TFish colour photo system). This pilot project was conducted together the Norwegian Hydrographic Service, the Institute of Marine Research (biology observations) and the Norwegian Defence Research Establishment (operation of ship and AUV). The test site reported here is the Vesterdjupet area, offshore Lofoten, northern Norway. The water depth is between 170 and 300 metres, with sediments ranging from gravel, cobbles and boulders to sandy mud. A cold-water coral reef, associated with bioclastic sediments was also present in the study area. The presentation will give an overview of the main findings and experiences gained from this pilot project with a focus on geological mapping and will also discuss the relevance of AUV-based mapping to large-area mapping programmes like MAREANO.

  6. Side-scan sonar techniques for the characterization of physical properties of artificial benthic habitats

    Directory of Open Access Journals (Sweden)

    Wen-Miin Tian

    2011-01-01

    Full Text Available Side-scan sonar observations conducted at Mito artificial habitat site in the southwest coast off Taiwan, documented the locations of both concrete cubic blocks (more than 10,000 units and scrapped steel boats (39 units deployed previously. Based on their geographic locations, the concrete cubic artificial reefs could be grouped into 14 reef sets. About 30% of the reefs were deployed out of the promulgated site area. For the purpose of artificial habitat site identification and fishery resources management, a database structure was designed to accommodate types and positions of reefs, information of reef sets, bathymetric contours, textures of bottom sediments and geomorphological characteristics. The effectiveness of Mito artificial habitat site was evaluated to be positive after the deployment of both concrete block reefs and steel boat reefs.Observações com sonar de varredura lateral ao largo de Mito na costa sudoeste de Taiwan, revelou a localização de mais de 10.000 blocos de concreto e 39 embarcações de ferro assentados previamente como recifes artificiais. Com base nas imagens obtidas, os cubos de concreto formam 14 grupos separados. Cerca de 30% das unidades de concreto foram assentadas fora das áreas previstas. Para a identificacão correta dos recifes artificiais e manejo adequado dos recursos pesqueiros, foi organizada uma base de dados com informações sobre forma, materiais e posição, e arranjo espacial das unidades recifais, bem como dados de batimetria, natureza do sedimento do fundo e geomorfologia. A eficiência dos recifes artificiais de Mito foi avaliada positivamente após o assentamento tanto das unidades de concreto quanto das embarcações de ferro.

  7. Monitoring the US ATLAS Network Infrastructure with perfSONAR-PS

    International Nuclear Information System (INIS)

    McKee, Shawn; Lake, Andrew; Laurens, Philippe; Severini, Horst; Wlodek, Tomasz; Wolff, Stephen; Zurawski, Jason

    2012-01-01

    Global scientific collaborations, such as ATLAS, continue to push the network requirements envelope. Data movement in this collaboration is routinely including the regular exchange of petabytes of datasets between the collection and analysis facilities in the coming years. These requirements place a high emphasis on networks functioning at peak efficiency and availability; the lack thereof could mean critical delays in the overall scientific progress of distributed data-intensive experiments like ATLAS. Network operations staff routinely must deal with problems deep in the infrastructure; this may be as benign as replacing a failing piece of equipment, or as complex as dealing with a multi-domain path that is experiencing data loss. In either case, it is crucial that effective monitoring and performance analysis tools are available to ease the burden of management. We will report on our experiences deploying and using the perfSONAR-PS Performance Toolkit at ATLAS sites in the United States. This software creates a dedicated monitoring server, capable of collecting and performing a wide range of passive and active network measurements. Each independent instance is managed locally, but able to federate on a global scale; enabling a full view of the network infrastructure that spans domain boundaries. This information, available through web service interfaces, can easily be retrieved to create customized applications. The US ATLAS collaboration has developed a centralized “dashboard” offering network administrators, users, and decision makers the ability to see the performance of the network at a glance. The dashboard framework includes the ability to notify users (alarm) when problems are found, thus allowing rapid response to potential problems and making perfSONAR-PS crucial to the operation of our distributed computing infrastructure.

  8. A Theoretical Study of Microwave Beam Absorption by a Rectenna

    Science.gov (United States)

    Ott, J. H.; Rice, J. S.; Thorn, D. C.

    1981-01-01

    The theoretical operational parameters for the workable satellite power system were examined. The system requirements for efficient transmission and reception of an environmentally benign microwave beam were determined.

  9. Evaluation of Four Supervised Learning Methods for Benthic Habitat Mapping Using Backscatter from Multi-Beam Sonar

    Directory of Open Access Journals (Sweden)

    Jacquomo Monk

    2012-11-01

    Full Text Available An understanding of the distribution and extent of marine habitats is essential for the implementation of ecosystem-based management strategies. Historically this had been difficult in marine environments until the advancement of acoustic sensors. This study demonstrates the applicability of supervised learning techniques for benthic habitat characterization using angular backscatter response data. With the advancement of multibeam echo-sounder (MBES technology, full coverage datasets of physical structure over vast regions of the seafloor are now achievable. Supervised learning methods typically applied to terrestrial remote sensing provide a cost-effective approach for habitat characterization in marine systems. However the comparison of the relative performance of different classifiers using acoustic data is limited. Characterization of acoustic backscatter data from MBES using four different supervised learning methods to generate benthic habitat maps is presented. Maximum Likelihood Classifier (MLC, Quick, Unbiased, Efficient Statistical Tree (QUEST, Random Forest (RF and Support Vector Machine (SVM were evaluated to classify angular backscatter response into habitat classes using training data acquired from underwater video observations. Results for biota classifications indicated that SVM and RF produced the highest accuracies, followed by QUEST and MLC, respectively. The most important backscatter data were from the moderate incidence angles between 30° and 50°. This study presents initial results for understanding how acoustic backscatter from MBES can be optimized for the characterization of marine benthic biological habitats.

  10. Transcending Transmission

    DEFF Research Database (Denmark)

    Schoeneborn, Dennis; Trittin, Hannah

    2013-01-01

    Purpose – Extant research on corporate social responsibility (CSR) communication primarily relies on a transmission model of communication that treats organizations and communication as distinct phenomena. This approach has been criticized for neglecting the formative role of communication...... in the emergence of organizations. This paper seeks to propose to reconceptualize CSR communication by drawing on the “communication constitutes organizations” (CCO) perspective. Design/methodology/approach – This is a conceptual paper that explores the implications of switching from an instrumental...... to a constitutive notion of communication. Findings – The study brings forth four main findings: from the CCO view, organizations are constituted by several, partly dissonant, and potentially contradictory communicative practices. From that viewpoint, the potential impact of CSR communication becomes a matter...

  11. Beam loading

    OpenAIRE

    Boussard, Daniel

    1987-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superco...

  12. Molecular beams

    International Nuclear Information System (INIS)

    Pendelbury, J.M.; Smith, K.F.

    1987-01-01

    Studies with directed collision-free beams of particles continue to play an important role in the development of modern physics and chemistry. The deflections suffered by such beams as they pass through electric and magnetic fields or laser radiation provide some of the most direct information about the individual constituents of the beam; the scattering observed when two beams intersect yields important data about the intermolecular forces responsible for the scattering. (author)

  13. Beam properties and stability of a flattening-filter free 7 MV beam--An overview

    International Nuclear Information System (INIS)

    Dzierma, Yvonne; Licht, Norbert; Nuesken, Frank; Ruebe, Christian

    2012-01-01

    Purpose: Several works have recently focused on flattening-filter-free (FFF) beams of linear accelerators of various companies (in particular, Varian and Elekta), but no overview as yet exists for the flattening-filter free 7XU beam (Siemens Artiste). Methods: Dosimetric properties of the 7XU beam were measured in May and September 2011. We present depth dose curves and beam profiles, output factors, and MLC transmission and assess the stability of the measurements. The 7XU beam was commissioned in the Pinnacle³ treatment planning system (TPS), and modeling results including the spectrum are presented. Results: The percent depth dose curve of the 7XU beam is similar to the flat 6X beam line, with a slightly smaller surface dose. The beam profiles show the characteristic shape of flattening-filter free beams, with deviations between measurements of generally less than 1%. The output factors of the 7XU beam decrease more slowly than for the 6X beam. The MLC transmission is comparable but slightly less for the 7XU beam. The 7XU beam can be adequately modeled by the Pinnacle³ TPS, with successful dosimetric verification. The spectrum of the 7XU beam has lower photon fluence up to approximately 2.5 MeV and higher fluence beyond, with a slightly higher mean energy. Conclusions: The 7XU beam has been commissioned for clinical use after successful modeling, stability checks, and dosimetric verification.

  14. Development of a transmission positron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Matsuya, M., E-mail: matsuya@jeol.co.jp [JEOL Ltd., 1-2 Musashino, 3-Chome, Akishima, Tokyo 196-8558 (Japan); Jinno, S. [Department of Applied Chemistry, Chiba University, Yayoi, Inage, Chiba, Chiba 263-8552 (Japan); Ootsuka, T.; Inoue, M. [JEOL Ltd., 1-2 Musashino, 3-Chome, Akishima, Tokyo 196-8558 (Japan); Kurihara, T. [High Energy Accelerator Research Organization, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Doyama, M.; Inoue, M. [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0913 (Japan); Fujinami, M. [Department of Applied Chemistry, Chiba University, Yayoi, Inage, Chiba, Chiba 263-8552 (Japan)

    2011-07-21

    A practical transmission positron microscope (TPM) JEM-1011B has been developed to survey differences in the interaction of positron and electron beams with materials, and is installed in the Slow Positron Facility of High Energy Accelerator Research Organization (KEK). The TPM can share positron and electron beams, and can also be used as a transmission electron microscope (TEM). Positron transmission images up to magnification 10,000x (resolution: 50 nm) and positron diffraction patterns up to 044 family were successfully obtained by the TPM comparing them with those of electrons. The differences in material transmittances for both beams have been measured, and can be explained by the calculated results of the Monte Carlo simulation code PENELOPE-2008.

  15. 3D Imaging with a Sonar Sensor and an Automated 3-Axes Frame for Selective Spraying in Controlled Conditions

    Directory of Open Access Journals (Sweden)

    David Reiser

    2017-02-01

    Full Text Available Autonomous selective spraying could be a way for agriculture to reduce production costs, save resources, protect the environment and help to fulfill specific pesticide regulations. The objective of this paper was to investigate the use of a low-cost sonar sensor for autonomous selective spraying of single plants. For this, a belt driven autonomous robot was used with an attached 3-axes frame with three degrees of freedom. In the tool center point (TCP of the 3-axes frame, a sonar sensor and a spray valve were attached to create a point cloud representation of the surface, detect plants in the area and perform selective spraying. The autonomous robot was tested on replicates of artificial crop plants. The location of each plant was identified out of the acquired point cloud with the help of Euclidian clustering. The gained plant positions were spatially transformed from the coordinates of the sonar sensor to the valve location to determine the exact irrigation points. The results showed that the robot was able to automatically detect the position of each plant with an accuracy of 2.7 cm and could spray on these selected points. This selective spraying reduced the used liquid by 72%, when comparing it to a conventional spraying method in the same conditions.

  16. Beam diagnostics

    International Nuclear Information System (INIS)

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-01-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the open-quotes Boosterclose quotes and open-quotes ATLASclose quotes linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates

  17. Broad-band beam buncher

    International Nuclear Information System (INIS)

    Goldberg, D.A.; Flood, W.S.; Arthur, A.A.; Voelker, F.

    1986-01-01

    This patent describes a broad-band beam buncher. This beam buncher consists of: a housing adapted to be eacuated, an electron gun in the housing for producing a beam of electrons, buncher means in the housing forming a buncher cavity which has an entrance opening for receiving the electron beam and an exit opening through which the electron beam passes out of the buncher cavity, a drift tube electrode in the buncher cavity and disposed between the entrance opening and the exit opening with first and second gaps between the drift tube electrode and the entrance and exit openings, the drift tube electrode which has a first drift space through which the electron beam passes in traveling between the entrance and exit openings, modulating means for supplying an ultrahigh frequeny modulating signal to the drift tube electrode for producing velocity modulation of the electrons in the electron beam as the electrons pass through the buncher cavity and the drift tube electrode between the entrance opening and the exit opening, drift space means in the housing forming a second drift space for receiving the velocity modulated electron beam from the exit opening, the velocity modulated electron beam being bunched as it passes along the second drift space, the drift space means has a discharge opening through which the electron beam is discharged from the second drift space after being bunched therein, the modulating means containing a signal source for producing an ultrahigh frequency signal, a transmission line connected between the signal source and the drift tube electrode, and terminating means connected to the drift tube electrode for terminating the transmission line in approximately its characteristic impedance to afford a broad response band with minimum 6 variations therein

  18. Resolving beam transport problems in electrostatic accelerators

    International Nuclear Information System (INIS)

    Larson, J.D.

    1977-01-01

    A review is given of problem areas in beam transmission which are frequently encountered during the design, operation and upgrading of electrostatic accelerators. Examples are provided of analytic procedures that clarify accelerator ion optics and lead to more effective beam transport. Suggestions are made for evaluating accelerator design with the goal of improved performance

  19. Resolving beam transport problems in electrostatic accelerators

    International Nuclear Information System (INIS)

    Larson, J.D.

    1977-01-01

    This paper reviews problem areas in beam transmission which are frequently encountered during the design, operation and upgrading of electrostatic accelerators. Examples are provided of analytic procedures that clarify accelerator ion optics and lead to more effective beam transport. Suggestions are made for evaluating accelerator design with the goal of improved performance

  20. Object Classification in Semi Structured Enviroment Using Forward-Looking Sonar

    Directory of Open Access Journals (Sweden)

    Matheus dos Santos

    2017-09-01

    Full Text Available The submarine exploration using robots has been increasing in recent years. The automation of tasks such as monitoring, inspection, and underwater maintenance requires the understanding of the robot’s environment. The object recognition in the scene is becoming a critical issue for these systems. On this work, an underwater object classification pipeline applied in acoustic images acquired by Forward-Looking Sonar (FLS are studied. The object segmentation combines thresholding, connected pixels searching and peak of intensity analyzing techniques. The object descriptor extract intensity and geometric features of the detected objects. A comparison between the Support Vector Machine, K-Nearest Neighbors, and Random Trees classifiers are presented. An open-source tool was developed to annotate and classify the objects and evaluate their classification performance. The proposed method efficiently segments and classifies the structures in the scene using a real dataset acquired by an underwater vehicle in a harbor area. Experimental results demonstrate the robustness and accuracy of the method described in this paper.

  1. Using ground-penetrating radar and sidescan sonar to compare lake bottom geology in New England

    Science.gov (United States)

    Nesbitt, I. M.; Campbell, S. W.; Arcone, S. A.; Smith, S. M.

    2017-12-01

    Post-Laurentide Ice Sheet erosion and re-deposition has had a significant influence on the geomorphology of New England. Anthropogenic activities such as forestry, farming, and construction of infrastructure such as dams and associated lake reservoirs, has further contributed to near surface changes. Unfortunately, these surface dynamics are difficult to constrain, both in space and time. One analog that can be used to estimate erosion and deposition, lake basin sedimentation, is typically derived from lake bottom sediment core samples. Reliance on core records assumes that derived sedimentation rates are representative of the broader watershed, despite being only a single point measurement. Geophysical surveys suggest that this assumption can be highly erroneous and unrepresentative of an entire lake basin. Herein, we conducted ground-penetrating radar (GPR) and side-scan sonar (SSS) surveys of multiple lakes in Maine, New Hampshire, and Vermont which are representative of different basin types to estimate sedimentation rates since Laurentide retreat. Subsequent age constraints from cores on multiple GPR-imaged horizons could be used to refine estimates of sedimentation rate change caused by evolving physical, biological, and chemical processes that control erosion, transport, and re-deposition. This presentation will provide a summary of GPR and SSS data collection methods, assumptions and limitations, structural and surficial interpretations, and key findings from multiple lake basins in New England. Results show that GPR and SSS are efficient, cost effective, and relatively accurate tools for helping to constrain lake erosion and deposition processes.

  2. Automatic classification techniques for type of sediment map from multibeam sonar data

    Science.gov (United States)

    Zakariya, R.; Abdullah, M. A.; Che Hasan, R.; Khalil, I.

    2018-02-01

    Sediment map can be important information for various applications such as oil drilling, environmental and pollution study. A study on sediment mapping was conducted at a natural reef (rock) in Pulau Payar using Sound Navigation and Ranging (SONAR) technology which is Multibeam Echosounder R2-Sonic. This study aims to determine sediment type by obtaining backscatter and bathymetry data from multibeam echosounder. Ground truth data were used to verify the classification produced. The method used to analyze ground truth samples consists of particle size analysis (PSA) and dry sieving methods. Different analysis being carried out due to different sizes of sediment sample obtained. The smaller size was analyzed using PSA with the brand CILAS while bigger size sediment was analyzed using sieve. For multibeam, data acquisition includes backscatter strength and bathymetry data were processed using QINSy, Qimera, and ArcGIS. This study shows the capability of multibeam data to differentiate the four types of sediments which are i) very coarse sand, ii) coarse sand, iii) very coarse silt and coarse silt. The accuracy was reported as 92.31% overall accuracy and 0.88 kappa coefficient.

  3. Sea ice draft in the Weddell Sea, measured by upward looking sonars

    Directory of Open Access Journals (Sweden)

    A. Behrendt

    2013-06-01

    Full Text Available The presented database contains time-referenced sea ice draft values from upward looking sonar (ULS measurements in the Weddell Sea, Antarctica. The sea ice draft data can be used to infer the thickness of the ice. They were collected during the period 1990–2008. In total, the database includes measurements from 13 locations in the Weddell Sea and was generated from more than 3.7 million measurements of sea ice draft. The files contain uncorrected raw drafts, corrected drafts and the basic parameters measured by the ULS. The measurement principle, the data processing procedure and the quality control are described in detail. To account for the unknown speed of sound in the water column above the ULS, two correction methods were applied to the draft data. The first method is based on defining a reference level from the identification of open water leads. The second method uses a model of sound speed in the oceanic mixed layer and is applied to ice draft in austral winter. Both methods are discussed and their accuracy is estimated. Finally, selected results of the processing are presented. The data can be downloaded from doi:10.1594/PANGAEA.785565.

  4. Implementation of Signal Processing in Stereo-Scopic Active Sonar Using Heterodyne System

    Directory of Open Access Journals (Sweden)

    BOKHARI Syed Umar

    2012-10-01

    Full Text Available “SONAR” is an acronym for sound ranging and navigation. It uses sound waves to detect an object in the surroundings and calculate its distance. This device has a very important applications in shipbuilding industry and military systems. Moreover it’s also being extensively used in deep sea research of new species of plants and minerals, where it is practically impossible for humans to go. The most important feature of this system is the usage of ultrasonicfrequency to detect objects that are important for data collection or detection. Transmitting an ultra sonic frequency using an electronic oscillator is not a very difficult task, the real challenge is to design a reciever that could carry out a particular modulation technique to convert an ultra-sonic frequency to an audiblefrequency. In this paper, we propose aseteroscopic active SONAR proto-type. Further, we performed a seriers of expeirments using modulation techniques. The results obtained from the experiments gives us a braod understanding of the different behaviour of asignal.

  5. Utilization of sonar technology and microcontroller towards reducing aviation hazards during ground handling of aircraft

    Science.gov (United States)

    Khanam, Mosammat Samia; Biswas, Debasish; Rashid, Mohsina; Salam, Md Abdus

    2017-12-01

    Safety is one of the most important factors in the field of aviation. Though, modern aircraft are equipped with many instruments/devices to enhance the flight safety but it is seen that accidents/incidents are never reduced to zero. Analysis of the statistical summary of Commercial Jet Airplane accidents highlights that fatal accidents that occurred worldwide from 2006 through 2015 is 11% during taxing, loading/unloading, parking and towing. Human, handling the aircrafts is one of the most important links in aircraft maintenance and hence play a significant role in aviation safety. Effort has been made in this paper to obviate human error in aviation and outline an affordable system that monitors the uneven surface &obstacles for safe "towing in" and "towing out" of an aircraft by the ground crew. The system revolves around implementation of sonar technology by microcontroller. Ultrasonic sensors can be installed on aircraft wings and tail section to identify the uneven surface &obstacles ahead and provide early warning to the maintenance ground crews.

  6. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  7. Beam loading

    International Nuclear Information System (INIS)

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed. (author)

  8. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2011-11-01

    Full Text Available The transformation of a Gaussian beam (GB) into a symmetrical higher order TEMp0 Laguerre Gaussian beam (LGB) intensity distribution of which is further rectified and transformed into a Gaussian intensity distribution in the plane of a converging...

  9. Study of electron beam production by a plasma focus

    International Nuclear Information System (INIS)

    Smith, J.R.; Luo, C.M.; Rhee, M.J.; Schneider, R.F.

    1983-01-01

    A preliminary investigation of the electron beam produced by a plasma focus device using a current charged transmission line is described. Electron beam currents as high as 10 kA were measured. Interaction of the extracted beam and the filling gas was studied using open shutter photography

  10. Beam transport calculations for the EN tandem installation

    International Nuclear Information System (INIS)

    Sparks, R.J.

    1980-12-01

    Transport of a charged particle beam through the new EN tandem accelerator installation of the Institute of Nuclear Sciences has been analysed using simplified mathematical models. The purpose is to identify the factors affecting transmission of the beam, and to arrive at a design for the system to inject the beam into the accelerator

  11. Beam Position Monitor Engineering

    International Nuclear Information System (INIS)

    Smith, Stephen R.

    1996-07-01

    The design of beam position monitors often involves challenging system design choices. Position transducers must be robust, accurate, and generate adequate position signal without unduly disturbing the beam. Electronics must be reliable and affordable, usually while meeting tough requirements on precision. accuracy, and dynamic range. These requirements may be difficult to achieve simultaneously, leading the designer into interesting opportunities for optimization or compromise. Some useful techniques and tools are shown. Both finite element analysis and analytic techniques will be used to investigate quasi-static aspects of electromagnetic fields such as the impedance of and the coupling of beam to striplines or buttons. Finite-element tools will be used to understand dynamic aspects of the electromagnetic fields of beams, such as wake-fields and transmission-line and cavity effects in vacuum-to-air feed through. Mathematical modeling of electrical signals through a processing chain will be demonstrated, in particular to illuminate areas where neither a pure time-domain nor a pure frequency-domain analysis is obviously advantageous. Emphasis will be on calculational techniques, in particular on using both time-domain and frequency domain approaches to the applicable parts of interesting problems

  12. Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Fink, S.; Porter, K.; Mudd, C.; Rogers, J.

    2011-02-01

    The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations.

  13. Optimal predator risk assessment by the sonar-jamming arctiine moth Bertholdia trigona.

    Directory of Open Access Journals (Sweden)

    Aaron J Corcoran

    Full Text Available Nearly all animals face a tradeoff between seeking food and mates and avoiding predation. Optimal escape theory holds that an animal confronted with a predator should only flee when benefits of flight (increased survival outweigh the costs (energetic costs, lost foraging time, etc.. We propose a model for prey risk assessment based on the predator's stage of attack. Risk level should increase rapidly from when the predator detects the prey to when it commits to the attack. We tested this hypothesis using a predator--the echolocating bat--whose active biosonar reveals its stage of attack. We used a prey defense--clicking used for sonar jamming by the tiger moth Bertholdia trigona--that can be readily studied in the field and laboratory and is enacted simultaneously with evasive flight. We predicted that prey employ defenses soon after being detected and targeted, and that prey defensive thresholds discriminate between legitimate predatory threats and false threats where a nearby prey is attacked. Laboratory and field experiments using playbacks of ultrasound signals and naturally behaving bats, respectively, confirmed our predictions. Moths clicked soon after bats detected and targeted them. Also, B. trigona clicking thresholds closely matched predicted optimal thresholds for discriminating legitimate and false predator threats for bats using search and approach phase echolocation--the period when bats are searching for and assessing prey. To our knowledge, this is the first quantitative study to correlate the sensory stimuli that trigger defensive behaviors with measurements of signals provided by predators during natural attacks in the field. We propose theoretical models for explaining prey risk assessment depending on the availability of cues that reveal a predator's stage of attack.

  14. Characterization of Sea Lamprey stream entry using dual‐frequency identification sonar

    Science.gov (United States)

    McCain, Erin L.; Johnson, Nicholas; Hrodey, Peter J.; Pangle, Kevin L.

    2018-01-01

    Effective methods to control invasive Sea Lampreys Petromyzon marinus in the Laurentian Great Lakes often rely on knowledge of the timing of the Sea Lamprey spawning migration, which has previously been characterized using data gathered from traps. Most assessment traps are located many kilometers upstream from the river mouth, so less is known about when Sea Lampreys enter spawning streams and which environmental cues trigger their transition from lakes to rivers. To decide how to develop barriers and traps that target Sea Lampreys when they enter a stream, the stream entry of Sea Lampreys into a Lake Huron tributary during 2 years was assessed using dual‐frequency identification sonar (DIDSON). Sea Lampreys entered the stream in low densities when temperatures first reached 4°C, which was up to 6 weeks and a mean of 4 weeks earlier than when they were first captured in traps located upstream. The probability of stream entry was significantly affected by stream temperature and discharge, and stream entry timing peaked when stream temperatures rose to 12°C and discharge was high. Examination of the entry at a finer temporal resolution (i.e., minutes) indicated that Sea Lampreys did not exhibit social behavior (e.g., shoaling) during stream entry. Our findings indicate that Sea Lampreys may be vulnerable to alternative trap types near river mouths and hydraulic challenges associated with traditional traps. Also, seasonal migration barriers near stream mouths may need to be installed soon after ice‐out to effectively block the entire adult Sea Lamprey cohort from upstream spawning habitat.

  15. Innovative method for optimizing Side-Scan Sonar mapping: The blind band unveiled

    Science.gov (United States)

    Pergent, Gérard; Monnier, Briac; Clabaut, Philippe; Gascon, Gilles; Pergent-Martini, Christine; Valette-Sansevin, Audrey

    2017-07-01

    Over the past few years, the mapping of Mediterranean marine habitats has become a priority for scientists, environment managers and stakeholders, in particular in order to comply with European directives (Water Framework Directive and Marine Strategy Framework Directive) and to implement legislation to ensure their conservation. Side-scan sonar (SSS) is recognised as one of the most effective tool for underwater mapping. However, interpretation of acoustic data (sonograms) requires extensive field calibration and the ground-truthing process remains essential. Several techniques are commonly used, with sampling methods involving grabs, scuba diving observations or Remotely Operated Vehicle (ROV) underwater video recordings. All these techniques are time consuming, expensive and only provide sporadic informations. In the present study, the possibility of coupling a camera with a SSS and acquiring underwater videos in a continuous way has been tested. During the 'PosidCorse' oceanographic survey carried out along the eastern coast of Corsica, optical and acoustic data were respectively obtained using a GoPro™ camera and a Klein 3000™ SSS. Thereby, five profiles were performed between 10 and 50 m depth, corresponding to more than 20 km of data acquisition. The vertical images recorded with the camera fixed under the SSS and positioned facing downwards provided photo mosaics of very good quality corresponding to the entire sonograms's blind band. From the photo mosaics, 94% of the different bottom types and main habitats have been identified; specific structures linked to hydrodynamics conditions, anthropic and biological activities have also been observed as well as the substrate on which the Posidonia oceanica meadow grows. The association between acoustic data and underwater videos has proved to be a non-destructive and cost-effective method for ground-truthing in marine habitats mapping. Nevertheless, in order to optimize the results over the next surveys

  16. Optimal Predator Risk Assessment by the Sonar-Jamming Arctiine Moth Bertholdia trigona

    Science.gov (United States)

    Corcoran, Aaron J.; Wagner, Ryan D.; Conner, William E.

    2013-01-01

    Nearly all animals face a tradeoff between seeking food and mates and avoiding predation. Optimal escape theory holds that an animal confronted with a predator should only flee when benefits of flight (increased survival) outweigh the costs (energetic costs, lost foraging time, etc.). We propose a model for prey risk assessment based on the predator's stage of attack. Risk level should increase rapidly from when the predator detects the prey to when it commits to the attack. We tested this hypothesis using a predator – the echolocating bat – whose active biosonar reveals its stage of attack. We used a prey defense – clicking used for sonar jamming by the tiger moth Bertholdia trigona– that can be readily studied in the field and laboratory and is enacted simultaneously with evasive flight. We predicted that prey employ defenses soon after being detected and targeted, and that prey defensive thresholds discriminate between legitimate predatory threats and false threats where a nearby prey is attacked. Laboratory and field experiments using playbacks of ultrasound signals and naturally behaving bats, respectively, confirmed our predictions. Moths clicked soon after bats detected and targeted them. Also, B. trigona clicking thresholds closely matched predicted optimal thresholds for discriminating legitimate and false predator threats for bats using search and approach phase echolocation – the period when bats are searching for and assessing prey. To our knowledge, this is the first quantitative study to correlate the sensory stimuli that trigger defensive behaviors with measurements of signals provided by predators during natural attacks in the field. We propose theoretical models for explaining prey risk assessment depending on the availability of cues that reveal a predator's stage of attack. PMID:23671686

  17. Transmission X-ray mirror

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  18. Coherent beam-beam effect

    International Nuclear Information System (INIS)

    Chao, A.W.; Keil, E.

    1979-06-01

    The stability of the coherent beam-beam effect between rigid bunches is studied analytically and numerically for a linear force by evaluating eigenvalues. For a realistic force, the stability is investigated by following the bunches for many revolutions. 4 refs., 13 figs., 2 tabs

  19. Molecular beam epitaxial growth mechanism of ZnSe epilayers on (100) GaAs as determined by reflection high-energy electron diffraction, transmission electron microscopy and X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Ruppert, P.; Hommel, D.; Behr, T.; Heinke, H.; Waag, A.; Landwehr, G. (Physikalisches Inst., Univ. Wuerzburg (Germany))

    1994-04-14

    The properties of molecular beam epitaxial growth of ZnSe epilayers deposited directly on a GaAs substrate are compared to those grown on a GaAs buffer layer. The superior quality of the latter is confirmed by RHEED, TEM and X-ray diffraction. Based on RHEED oscillation studies, a model explaining the dependence of the ZnSe growth rate on Zn and Se fluxes and the substrate temperature is developed taking into account physisorbed and chemisorbed states. For partially relaxed epilayers, the correlation between the relaxation state and the crystalline mosaicity, as found by high resolution X-ray diffraction, is discussed

  20. Argonne National Laboratory heavy ion beam transport experiments with a 2 mA 80 keV Xe+1 source

    International Nuclear Information System (INIS)

    Mazarakis, M.; Price, D.; Watson, J.

    1978-01-01

    The critical dimensions of the Argonne heavy ion beam transmission experiments and the experimental set-up are considered. Experimental results of beam transmission and emittance measurements are discussed

  1. Characteristics of a sandy depositional lobe on the outer Mississippi fan from SeaMARC IA sidescan sonar images

    Science.gov (United States)

    Twichell, David C.; Schwab, William C.; Nelson, C. Hans; Kenyon, Neil H.; Lee, Homa J.

    1992-01-01

    SeaMARC IA sidescan sonar images of the distal reaches of a depositional lobe on the Mississippi Fan show that channelized rather than unconfined transport was the dominant transport mechanism for coarse-grained sediment during the formation of this part of the deep-sea fan. Overbank sheet flow of sands was not an important process in the transport and deposition of the sandy and silty sediment found on this fan. The dendritic distributary pattern and the high order of splaying of the channels, only one of which appears to have been active at a time, suggest that coarse-grained deposits on this fan are laterally discontinuous.

  2. Mixed beams for the nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Breese, M.B.H.; Legge, G.L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Recently the Micro-Analytical Research Centre (MARC) at Melbourne University has developed a technique to provide mixed beams of ions for a magnetically focussed nuclear microprobe. Such a mixed beam is defined as two (or more) beams of different species ions that can quickly and easily be made to have the same magnetic rigidity R{sub m} = (mE/q{sup 2}) and therefore be transported, focused and scanned the same in a magnetic nuclear microprobe. The production of mixed beams in an electrostatically focussed micro- probe have already been demonstrated. This paper will show how mixed beams can be produced on a single-ended accelerator. Indications of how to produce them on a tandem will also be given. Applications of these mixed beams in micro-lithography, scanning transmission ion microscopy (STIM) imaging and ion beam induced charge (IBIC) imaging will also be presented. 3 refs., 3 figs.

  3. Mixed beams for the nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A; Breese, M B.H.; Legge, G L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Recently the Micro-Analytical Research Centre (MARC) at Melbourne University has developed a technique to provide mixed beams of ions for a magnetically focussed nuclear microprobe. Such a mixed beam is defined as two (or more) beams of different species ions that can quickly and easily be made to have the same magnetic rigidity R{sub m} = (mE/q{sup 2}) and therefore be transported, focused and scanned the same in a magnetic nuclear microprobe. The production of mixed beams in an electrostatically focussed micro- probe have already been demonstrated. This paper will show how mixed beams can be produced on a single-ended accelerator. Indications of how to produce them on a tandem will also be given. Applications of these mixed beams in micro-lithography, scanning transmission ion microscopy (STIM) imaging and ion beam induced charge (IBIC) imaging will also be presented. 3 refs., 3 figs.

  4. Nanochannel alignment analysis by scanning transmission ion microscopy

    DEFF Research Database (Denmark)

    Rajta, I.; Gál, G.A.B.; Szilasi, S.Z.

    2010-01-01

    In this paper a study on the ion transmission ratio of a nanoporous alumina sample is presented. The sample was investigated by scanning transmission ion microscopy (STIM) with different beam sizes. The hexagonally close-packed AlO nanocapillary array, realized as a suspended membrane of 15 νm...

  5. Beam transport

    International Nuclear Information System (INIS)

    1988-01-01

    Considerable experience has now been gained with the various beam transport lines, and a number of minor changes have been made to improve the ease of operation. These include: replacement of certain little-used slits by profile monitors (harps or scanners); relocation of steering magnets, closer to diagnostic harps or profile scanners; installation of a scanner inside the isocentric neutron therapy system; and conversion of a 2-doublet quadrupole telescope (on the neutron therapy beamline) to a 2-triplet telescope. The beam-swinger project has been delayed by very late delivery of the magnet iron to the manufacturer, but is now progressing smoothly. The K=600 spectrometer magnets have now been delivered and are being assembled for field mapping. The x,y-table with its associated mapping equipment is complete, together with the driver software. One of the experimental areas has been dedicated to the production of collimated neutron beams and has been equipped with a bending magnet and beam dump, together with steel collimators fixed at 4 degrees intervals from 0 degrees to 16 degrees. Changes to the target cooling and shielding system for isotope production have led to a request for much smaller beam spot sizes on target, and preparations have been made for rearrangement of the isotope beamline to permit installation of quadrupole triplets on the three beamlines after the switching magnet. A practical system of quadrupoles for matching beam properties to the spectrometer has been designed. 6 figs

  6. Higher-Order Statistics for the Detection of Small Objects in a Noisy Background Application on Sonar Imaging

    Directory of Open Access Journals (Sweden)

    M. Amate

    2007-01-01

    Full Text Available An original algorithm for the detection of small objects in a noisy background is proposed. Its application to underwater objects detection by sonar imaging is addressed. This new method is based on the use of higher-order statistics (HOS that are locally estimated on the images. The proposed algorithm is divided into two steps. In a first step, HOS (skewness and kurtosis are estimated locally using a square sliding computation window. Small deterministic objects have different statistical properties from the background they are thus highlighted. The influence of the signal-to-noise ratio (SNR on the results is studied in the case of Gaussian noise. Mathematical expressions of the estimators and of the expected performances are derived and are experimentally confirmed. In a second step, the results are focused by a matched filter using a theoretical model. This enables the precise localization of the regions of interest. The proposed method generalizes to other statistical distributions and we derive the theoretical expressions of the HOS estimators in the case of a Weibull distribution (both when only noise is present or when a small deterministic object is present within the filtering window. This enables the application of the proposed technique to the processing of synthetic aperture sonar data containing underwater mines whose echoes have to be detected and located. Results on real data sets are presented and quantitatively evaluated using receiver operating characteristic (ROC curves.

  7. Acoustic Imaging of Selected Areas of Gdansk Bay with the Aid of Parametric Echosounder and Side-Scan Sonar

    Directory of Open Access Journals (Sweden)

    Grelowska Grażyna

    2017-12-01

    Full Text Available The article presents and analyses the data recorded during sounding of the Gdansk Bay seabed with the aid of a parametric echosounder and a side-scan sonar. The accuracy of seabed structure examination, as a condition for obtaining valuable results, requires correct configuration of echolocation devices and proper calibration of peripheral devices, such as the survey unit geographical position sensor - GPS, the navigation unit, the MRU-Z sensor of pitch, roll and heave, and the sound velocity meter, which deliver the data to the bathymetric measurement system. Parametric seabed profilers deliver two types of data: the envelope, and the detailed echo signal without processing. The envelope is used for data visualisation in the form of online echograms, while the echo signal is stored for further analyses, to be performed using dedicated software or, after relevant conversion, in arbitrary programming environment1. The presented data analysis is illustrated by selected sample images recorded by the parametric echosounder and the side-scan sonar during Gdansk Bay sounding.

  8. Sonar atlas of caverns comprising the U.S. Strategic Petroleum Reserve. Volume 2, Big Hill Site, Texas.

    Energy Technology Data Exchange (ETDEWEB)

    Rautman, Christopher Arthur; Lord, Anna Snider

    2007-08-01

    Downhole sonar surveys from the four active U.S. Strategic Petroleum Reserve sites have been modeled and used to generate a four-volume sonar atlas, showing the three-dimensional geometry of each cavern. This volume 2 focuses on the Big Hill SPR site, located in southeastern Texas. Volumes 1, 3, and 4, respectively, present images for the Bayou Choctaw SPR site, Louisiana, the Bryan Mound SPR site, Texas, and the West Hackberry SPR site, Louisiana. The atlas uses a consistent presentation format throughout. The basic geometric measurements provided by the down-cavern surveys have also been used to generate a number of geometric attributes, the values of which have been mapped onto the geometric form of each cavern using a color-shading scheme. The intent of the various geometrical attributes is to highlight deviations of the cavern shape from the idealized cylindrical form of a carefully leached underground storage cavern in salt. The atlas format does not allow interpretation of such geometric deviations and anomalies. However, significant geometric anomalies, not directly related to the leaching history of the cavern, may provide insight into the internal structure of the relevant salt dome.

  9. Sonar atlas of caverns comprising the U.S. Strategic Petroleum Reserve. Volume 1, Bayou Choctaw site, Louisiana.

    Energy Technology Data Exchange (ETDEWEB)

    Rautman, Christopher Arthur; Lord, Anna Snider

    2007-10-01

    Downhole sonar surveys from the four active U.S. Strategic Petroleum Reserve sites have been modeled and used to generate a four-volume sonar atlas, showing the three-dimensional geometry of each cavern. This volume 1 focuses on the Bayou Choctaw SPR site, located in southern Louisiana. Volumes 2, 3, and 4, respectively, present images for the Big Hill SPR site, Texas, the Bryan Mound SPR site, Texas, and the West Hackberry SPR site, Louisiana. The atlas uses a consistent presentation format throughout. The basic geometric measurements provided by the down-cavern surveys have also been used to generate a number of geometric attributes, the values of which have been mapped onto the geometric form of each cavern using a color-shading scheme. The intent of the various geometrical attributes is to highlight deviations of the cavern shape from the idealized cylindrical form of a carefully leached underground storage cavern in salt. The atlas format does not allow interpretation of such geometric deviations and anomalies. However, significant geometric anomalies, not directly related to the leaching history of the cavern, may provide insight into the internal structure of the relevant salt dome.

  10. Sonar atlas of caverns comprising the U.S. Strategic Petroleum Reserve. Volume 3, Bryan Mound Site, Texas.

    Energy Technology Data Exchange (ETDEWEB)

    Rautman, Christopher Arthur; Lord, Anna Snider

    2007-09-01

    Downhole sonar surveys from the four active U.S. Strategic Petroleum Reserve sites have been modeled and used to generate a four-volume sonar atlas, showing the three-dimensional geometry of each cavern. This volume 3 focuses on the Bryan Mound SPR site, located in southeastern Texas. Volumes 1, 2, and 4, respectively, present images for the Bayou Choctaw SPR site, Louisiana, the Big Hill SPR site, Texas, and the West Hackberry SPR site, Louisiana. The atlas uses a consistent presentation format throughout. The basic geometric measurements provided by the down-cavern surveys have also been used to generate a number of geometric attributes, the values of which have been mapped onto the geometric form of each cavern using a color-shading scheme. The intent of the various geometrical attributes is to highlight deviations of the cavern shape from the idealized cylindrical form of a carefully leached underground storage cavern in salt. The atlas format does not allow interpretation of such geometric deviations and anomalies. However, significant geometric anomalies, not directly related to the leaching history of the cavern, may provide insight into the internal structure of the relevant salt dome.

  11. Sonar atlas of caverns comprising the U.S. Strategic Petroleum Reserve. Volume 4, West Hackberry site, Louisiana.

    Energy Technology Data Exchange (ETDEWEB)

    Rautman, Christopher Arthur; Lord, Anna Snider

    2007-09-01

    Downhole sonar surveys from the four active U.S. Strategic Petroleum Reserve sites have been modeled and used to generate a four-volume sonar atlas, showing the three-dimensional geometry of each cavern. This volume 4 focuses on the West Hackberry SPR site, located in southwestern Louisiana. Volumes 1, 2, and 3, respectively, present images for the Bayou Choctaw SPR site, Louisiana, the Big Hill SPR site, Texas, and the Bryan Mound SPR site, Texas. The atlas uses a consistent presentation format throughout. The basic geometric measurements provided by the down-cavern surveys have also been used to generate a number of geometric attributes, the values of which have been mapped onto the geometric form of each cavern using a color-shading scheme. The intent of the various geometrical attributes is to highlight deviations of the cavern shape from the idealized cylindrical form of a carefully leached underground storage cavern in salt. The atlas format does not allow interpretation of such geometric deviations and anomalies. However, significant geometric anomalies, not directly related to the leaching history of the cavern, may provide insight into the internal structure of the relevant salt dome.

  12. Quantitative Analysis of Electron Beam Damage in Organic Thin Films

    OpenAIRE

    Leijten, Zino J. W. A.; Keizer, Arthur D. A.; de With, Gijsbertus; Friedrich, Heiner

    2017-01-01

    In transmission electron microscopy (TEM) the interaction of an electron beam with polymers such as P3HT:PCBM photovoltaic nanocomposites results in electron beam damage, which is the most important factor limiting acquisition of structural or chemical data at high spatial resolution. Beam effects can vary depending on parameters such as electron dose rate, temperature during imaging, and the presence of water and oxygen in the sample. Furthermore, beam damage will occur at different length s...

  13. A Physical Description of the Response of Coupled Beams

    DEFF Research Database (Denmark)

    Hugin, Claus Thomas

    1997-01-01

    An analytical method is presented for computing the vibrational response and the net transmitted power of bending wave fields in system consisting of coupled finite beams. The method is based on a wave approach that utilises the reflection and transmission coefficients of the different beam joint...... are valid for frequencies above which the influence of the reflected near fields for each of the beam elements is negligible. The method is demonstrated on different configurations of beams coupled in extension of each other....

  14. Underwater Cylindrical Object Detection Using the Spectral Features of Active Sonar Signals with Logistic Regression Models

    Directory of Open Access Journals (Sweden)

    Yoojeong Seo

    2018-01-01

    Full Text Available The issue of detecting objects bottoming on the sea floor is significant in various fields including civilian and military areas. The objective of this study is to investigate the logistic regression model to discriminate the target from the clutter and to verify the possibility of applying the model trained by the simulated data generated by the mathematical model to the real experimental data because it is not easy to obtain sufficient data in the underwater field. In the first stage of this study, when the clutter signal energy is so strong that the detection of a target is difficult, the logistic regression model is employed to distinguish the strong clutter signal and the target signal. Previous studies have found that if the clutter energy is larger, false detection occurs even for the various existing detection schemes. For this reason, the discrete Fourier transform (DFT magnitude spectrum of acoustic signals received by active sonar is applied to train the model to distinguish whether the received signal contains a target signal or not. The goodness of fit of the model is verified in terms of receiver operation characteristic (ROC, area under ROC curve (AUC, and classification table. The detection performance of the proposed model is evaluated in terms of detection rate according to target to clutter ratio (TCR. Furthermore, the real experimental data are employed to test the proposed approach. When using the experimental data to test the model, the logistic regression model is trained by the simulated data that are generated based on the mathematical model for the backscattering of the cylindrical object. The mathematical model is developed according to the size of the cylinder used in the experiment. Since the information on the experimental environment including the sound speed, the sediment type and such is not available, once simulated data are generated under various conditions, valid simulated data are selected using 70% of the

  15. Quantum beams

    International Nuclear Information System (INIS)

    Uesaka, Mitsuru

    2003-01-01

    Present state and future prospect are described on quantum beams for medical use. Efforts for compactness of linac for advanced cancer therapy have brought about the production of machines like Accuray's CyberKnife and TOMOTHERAPY (Tomo Therapy Inc.) where the acceleration frequency of X-band (9-11 GHz) is used. For cervical vein angiography by the X-band linac, a compact hard X-ray source is developed which is based on the (reverse) Compton scattering through laser-electron collision. More intense beam and laser are necessary at present. A compact machine generating the particle beam of 10 MeV-1 GeV (laser-plasma accelerator) for cancer therapy is also developed using the recent compression technique (chirped-pulse amplification) to generate laser of >10 TW. Tokyo University is studying for the electron beam with energy of GeV order, for the laser-based synchrotron X-ray, and for imaging by the short pulse ion beam. Development of advanced compact accelerators is globally attempted. In Japan, a virtual laboratory by National Institute of Radiological Sciences (NIRS), a working group of universities and research facilities through the Ministry of Education, Culture, Sports, Science and Technology, started in 2001 for practical manufacturing of the above-mentioned machines for cancer therapy and for angiography. Virtual Factory (Inc.), a business venture, is to be stood in future. (N.I.)

  16. Fixed target beams

    CERN Document Server

    Kain, V; Cettour-Cave, S; Cornelis, K; Fraser, M A; Gatignon, L; Goddard, B; Velotti, F

    2017-01-01

    The CERN SPS (Super Proton Synchrotron) serves asLHC injector and provides beam for the North Area fixedtarget experiments. At low energy, the vertical acceptancebecomes critical with high intensity large emittance fixed tar-get beams. Optimizing the vertical available aperture is a keyingredient to optimize transmission and reduce activationaround the ring. During the 2016 run a tool was developed toprovide an automated local aperture scan around the entirering.The flux of particles slow extracted with the1/3inte-ger resonance from the Super Proton Synchrotron at CERNshould ideally be constant over the length of the extractionplateau, for optimum use of the beam by the fixed target ex-periments in the North Area. The extracted intensity is con-trolled in feed-forward correction of the horizontal tune viathe main SPS quadrupoles. The Mains power supply noiseat 50 Hz and harmonics is also corrected in feed-forwardby small amplitude tune modulation at the respective fre-quencies with a dedicated additional quad...

  17. Importance of beam-beam tune spread to collective beam-beam instability in hadron colliders

    International Nuclear Information System (INIS)

    Jin Lihui; Shi Jicong

    2004-01-01

    In hadron colliders, electron-beam compensation of beam-beam tune spread has been explored for a reduction of beam-beam effects. In this paper, effects of the tune-spread compensation on beam-beam instabilities were studied with a self-consistent beam-beam simulation in model lattices of Tevatron and Large Hodron Collider. It was found that the reduction of the tune spread with the electron-beam compensation could induce a coherent beam-beam instability. The merit of the compensation with different degrees of tune-spread reduction was evaluated based on beam-size growth. When two beams have a same betatron tune, the compensation could do more harm than good to the beams when only beam-beam effects are considered. If a tune split between two beams is large enough, the compensation with a small reduction of the tune spread could benefit beams as Landau damping suppresses the coherent beam-beam instability. The result indicates that nonlinear (nonintegrable) beam-beam effects could dominate beam dynamics and a reduction of beam-beam tune spread by introducing additional beam-beam interactions and reducing Landau damping may not improve the stability of beams

  18. Beam dynamics

    International Nuclear Information System (INIS)

    Abell, D; Adelmann, A; Amundson, J; Dragt, A; Mottershead, C; Neri, F; Pogorelov, I; Qiang, J; Ryne, R; Shalf, J; Siegerist, C; Spentzouris, P; Stern, E; Venturini, M; Walstrom, P

    2006-01-01

    We describe some of the accomplishments of the Beam Dynamics portion of the SciDAC Accelerator Science and Technology project. During the course of the project, our beam dynamics software has evolved from the era of different codes for each physical effect to the era of hybrid codes combining start-of-the-art implementations for multiple physical effects to the beginning of the era of true multi-physics frameworks. We describe some of the infrastructure that has been developed over the course of the project and advanced features of the most recent developments, the interplay betwen beam studies and simulations and applications to current machines at Fermilab. Finally we discuss current and future plans for simulations of the International Linear Collider

  19. Application of passive sonar technology to mineral processing and oil sands applications : if you can measure it, you can manage it

    Energy Technology Data Exchange (ETDEWEB)

    O' Keefe, C.; Viega, J.; Fernald, M. [CiDRA Corp., Wallingford, CT (United States)

    2007-07-01

    SONAR-based flow and entrained air measurement instruments were described. This new class of industrial flow and compositional analyzers was developed by CiDRA to provide new measurement insight and quantifiable value to industrial process operators. Passive sonar array-based processing units have been installed worldwide in several industrial applications and are particularly suited for a wide range of mineral processing applications, including slurry flow rate measurement and fluid characterization. This paper also described the SONAR-based, clamp-on SONARtrac technology, a scalable platform that provides several other value added measurements and information such as speed of sound, entrained air/gas, gas hold-up, and velocity profile. Oil sands, tailings and bitumen slurries present considerable measurement challenges for in-line flow measurement devices in terms of measurement accuracy, reliability and maintenance. The sonar-based technology platform has been used in a variety of oil sands processes, hydrotransport, and minerals beneficiation applications. This paper described these applications with particular reference to difficult slurry flow measurement and control in the areas of comminution and flotation such as mill discharge, hydrocyclone feed/overflow, final concentrate, thickener discharge, and tailings. 5 refs., 4 tabs., 23 figs.

  20. mos114_0402b.tif -- Side scan sonar image from survey effort HMPR-114-2004-02b in the Olympic Coast National Marine Sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar image of the sea floor was mosaiced from data collected in August 2004 onboard the NOAA vesselTatoosh. An EG&G 272 side scan system was used...

  1. mos119_0601c.tif-- Side scan sonar image from survey effort HMPR-119-2006-01c in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (120-210 m water depths) was mosaiced from acoustic data collected in April 2006 aboard the NOAA ship McArthurII. A...

  2. mos113_0401d.tif -- Side scan sonar image from survey effort HMPR-113-2004-01d in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (120-350 m water depths) was mosaiced from acoustic data collected in 2004 aboard the NOAA ship McArthurII. A Klein...

  3. The relation between Arctic sea ice surface elevation and draft: A case study using coincident AUV sonar and airborne scanning laser

    DEFF Research Database (Denmark)

    Doble, Martin J.; Skourup, Henriette; Wadhams, Peter

    2011-01-01

    Data are presented from a survey by airborne scanning laser profilometer and an AUV-mounted, upward looking swath sonar in the spring Beaufort Sea. The air-snow (surface elevation) and water-ice (draft) surfaces were mapped at 1 x 1 m resolution over a 300 x 300 m area. Data were separated into l...

  4. mos113_0401r.tif -- Side scan sonar image from survey effort HMPR-113-2004-01r in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (50-80 m water depths) was mosaiced from acoustic data collected in 2004 aboard the NOAA ship McArthurII.A Klein System...

  5. mos118_0503a.tif -- Side scan sonar image from survey effort HMPR-118-2005-03a in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (140-350 m water depths) was mosaiced from acoustic data collected in 2005 aboard the NOAA ship McArthurII. A Klein...

  6. hab108_0201_east.tif -- Side scan sonar image (East mosaic) from survey effort HMPR-108-2002-01 in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar image of the sea floor (120-350 m water depths) was mosaiced from data collected in 2002.An Edgetech DF1000 side scan system was used for...

  7. mos119_0601a.tif-- Side scan sonar image from survey effort HMPR-119-2006-01a in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This side scan sonar imagery of the sea floor (90-270 m water depths) was mosaiced from acoustic data collected in April 2006 aboard the NOAA ship McArthurII.A Klein...

  8. Obstacle evasion in free-space optical communications utilizing Airy beams

    Science.gov (United States)

    Zhu, Guoxuan; Wen, Yuanhui; Wu, Xiong; Chen, Yujie; Liu, Jie; Yu, Siyuan

    2018-03-01

    A high speed free-space optical communication system capable of self-bending signal transmission around line-of-sight obstacles is proposed and demonstrated. Airy beams are generated and controlled to achieve different propagating trajectories, and the signal transmission characteristics of these beams around the obstacle are investigated. Our results confirm that, by optimising their ballistic trajectories, Airy beams are able to bypass obstacles with more signal energy and thus improve the communication performance compared with normal Gaussian beams.

  9. Ponderomotive phase plate for transmission electron microscopes

    Science.gov (United States)

    Reed, Bryan W [Livermore, CA

    2012-07-10

    A ponderomotive phase plate system and method for controllably producing highly tunable phase contrast transfer functions in a transmission electron microscope (TEM) for high resolution and biological phase contrast imaging. The system and method includes a laser source and a beam transport system to produce a focused laser crossover as a phase plate, so that a ponderomotive potential of the focused laser crossover produces a scattering-angle-dependent phase shift in the electrons of the post-sample electron beam corresponding to a desired phase contrast transfer function.

  10. X-ray beam generator

    International Nuclear Information System (INIS)

    Koller, T.J.; Randmer, J.A.

    1977-01-01

    A method of minimizing the preferential angular absorption of the divergent beam from an X-ray generator is described. The generator consists of an X-ray shielded housing with an X-ray transmissive window symmetrically placed in radial alignment with a focal spot area on a sloped target surface of an X-ray tube in the housing. The X-ray tube may be of the stationary anode type or of the rotating anode type. (U.K.)

  11. Transmission on Balance 2006

    International Nuclear Information System (INIS)

    2007-02-01

    Every year he Dutch Transmission System Operator (TSO) TenneT issues the title publication 'Transmission on Balance'. This report provides information about the main technical operating results in the past year.

  12. Design of a transmission electron positron microscope

    International Nuclear Information System (INIS)

    Doyama, Masao; Inoue, M.; Kogure, Y.; Hayashi, Y.; Yoshii, T.; Kurihara, T.; Tsuno, K.

    2003-01-01

    This paper reports the plans and design of positron-electron microscopes being built at KEK (High Energy Accelerator Research Organization), Tsukuba, Japan. A used electron microscope is altered. The kinetic energies of positrons produced by accelerators or by nuclear decays are not a unique value but show a spread over in a wide range. Positron beam is guided to a transmission electron microscope (JEM100SX). Positrons are moderated by a tungsten foil, are accelerated and are focused on a nickel sheet. The monochromatic focused beam is injected into an electron microscope. The focusing and aberration of positrons are the same as electrons in a magnetic system which are used in commercial electron microscopes. Imaging plates are used to record positron images for the transmission electron microscope. (author)

  13. Influence of laser beam profiles on received power fluctuation

    Science.gov (United States)

    Dordova, Lucie; Diblik, Jan

    2011-09-01

    Gaussian beam is very often used for the transmission of information in optical wireless links. The usage of this optical beam has its advantages and, of course, disadvantages. This work focuses on possibilities of using laser beams with different distribution of optical intensity - Top Hat beam. Creation of the optical beam with selected optical intensity profile will be briefly described. Optical beams will propagate through the "clear" and stationary atmosphere in the experimental part of this work. These results will be compared with the data obtained after a laser beam is passed through the turbulent and attenuated atmosphere. We will use an ultrasound fog generator for laser beam attenuation testing. To create the turbulence, infra radiators will be applied. Particular results obtained from different atmospheric conditions will be compared and using different types of optical beams will be assessed.

  14. The automotive transmission book

    CERN Document Server

    Fischer, Robert; Jürgens, Gunter; Najork, Rolf; Pollak, Burkhard

    2015-01-01

    This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors, and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles.

  15. An Improved Azimuth Angle Estimation Method with a Single Acoustic Vector Sensor Based on an Active Sonar Detection System.

    Science.gov (United States)

    Zhao, Anbang; Ma, Lin; Ma, Xuefei; Hui, Juan

    2017-02-20

    In this paper, an improved azimuth angle estimation method with a single acoustic vector sensor (AVS) is proposed based on matched filtering theory. The proposed method is mainly applied in an active sonar detection system. According to the conventional passive method based on complex acoustic intensity measurement, the mathematical and physical model of this proposed method is described in detail. The computer simulation and lake experiments results indicate that this method can realize the azimuth angle estimation with high precision by using only a single AVS. Compared with the conventional method, the proposed method achieves better estimation performance. Moreover, the proposed method does not require complex operations in frequencydomain and achieves computational complexity reduction.

  16. An Improved Azimuth Angle Estimation Method with a Single Acoustic Vector Sensor Based on an Active Sonar Detection System

    Directory of Open Access Journals (Sweden)

    Anbang Zhao

    2017-02-01

    Full Text Available In this paper, an improved azimuth angle estimation method with a single acoustic vector sensor (AVS is proposed based on matched filtering theory. The proposed method is mainly applied in an active sonar detection system. According to the conventional passive method based on complex acoustic intensity measurement, the mathematical and physical model of this proposed method is described in detail. The computer simulation and lake experiments results indicate that this method can realize the azimuth angle estimation with high precision by using only a single AVS. Compared with the conventional method, the proposed method achieves better estimation performance. Moreover, the proposed method does not require complex operations in frequencydomain and achieves computational complexity reduction.

  17. Radiation transmission pipe thickness measurement system

    International Nuclear Information System (INIS)

    Higashi, Yasuhiko

    2010-01-01

    Fuji Electric Systems can be measured from the outer insulation of the transmission Characteristics and radiation detection equipment had been developed that can measure pipe wall thinning in plant and running, the recruitment of another three-beam calculation method by pipe thickness measurement system was developed to measure the thickness of the pipe side. This equipment has been possible to measure the thickness of the circumferential profile of the pipe attachment by adopting automatic rotation. (author)

  18. Intense relativistic electron beam: generation and propagation

    International Nuclear Information System (INIS)

    Mittal, K.C.; Mondal, J.

    2010-01-01

    A general review of relativistic electron beam extracted from explosive field emission diode has been presented here. The beam current in the diode gap taking into account cathode and anode plasma expansion velocity and excluding the self magnetic field effect is directly proportional to gap voltage V 3/2 and inversely proportional to the square of the effective diode gap (d-vt). In the limit of high current, self magnetic field focusing effect comes into play and results in a critical current at which pinching will take place. When the diode current exceeds the critical current, the electron flow is in the para-potential regime. Different diode geometries such as planner, coaxial, rod-pinched, reflex triode are discussed qualitatively. When the beam is injected into a vacuum drift tube the propagation of the beam is only possible in presence of a strong axial magnetic field which prevents the beam expansion in the radial direction. If the beam is injected in the drift tube filled with dense plasma, then the redistribution of the plasma electrons effectively neutralizes the beam space charge, resulting subsequent propagation of the beam along the drift tube. The beam propagation through neutral gas is similar to the plasma filled drift tube. In this case both the neutral gas pressure and the beam current regulate the transmission of the REB. (author)

  19. FEL options for power beaming

    International Nuclear Information System (INIS)

    Kim, K.J.; Zholents, A.A.; Zolotorev, M.S.; Vinokurov, N.A.

    1997-10-01

    The demand for the output power of communication satellites has been increasing exponentially. The satellite power is generated from solar panels which collect the sunlight and convert it to electrical power. The power per satellite is limited due to the limit in the practical size of the solar panel. One way to meet the power demand is to employ multiple satellites (up to 10) per the internationally agreed-upon ''slot'' in the geosynchronous earth orbit (GEO). However, this approach is very expensive due to the high cost of sending a satellite into a GEO orbit. An alternative approach is power beaming, i.e., to illuminate the solar panels with high power, highly-directed laser beams from earth. The power beaming generates more power per satellite for the same area of the solar panel. The minimum optical beam power, interesting for power beaming application, is P L = 200kW. The wavelength is chosen to be λ 0.84 microm, so that it is within one of the transmission windows of the air, and at the same time near the peak of the photo-voltaic conversion efficiency of Si, which is the commonly used material for the solar panels. Free electron lasers (FELs) are well suited for the power beaming application because they can provide high power with coherent wavefront, but without high energy density in media. In this article the authors discuss some principal issues, such as the choice of accelerator and electron gun, the choice of beam parameters, radiation hazards, technological availability, and overall efficiency and reliability of the installation. They also attempt to highlight the compromise between the cost of the primary installation, the operation cost, and the choice of technology, and its maturity. They then present several schemes for the accelerator-FEL systems based on RF accelerators. The initial electron beam accelerator up to the energy of a few MeV is more or less common for all these schemes

  20. Pellicle transmission uniformity requirements

    Science.gov (United States)

    Brown, Thomas L.; Ito, Kunihiro

    1998-12-01

    Controlling critical dimensions of devices is a constant battle for the photolithography engineer. Current DUV lithographic process exposure latitude is typically 12 to 15% of the total dose. A third of this exposure latitude budget may be used up by a variable related to masking that has not previously received much attention. The emphasis on pellicle transmission has been focused on increasing the average transmission. Much less, attention has been paid to transmission uniformity. This paper explores the total demand on the photospeed latitude budget, the causes of pellicle transmission nonuniformity and examines reasonable expectations for pellicle performance. Modeling is used to examine how the two primary errors in pellicle manufacturing contribute to nonuniformity in transmission. World-class pellicle transmission uniformity standards are discussed and a comparison made between specifications of other components in the photolithographic process. Specifications for other materials or parameters are used as benchmarks to develop a proposed industry standard for pellicle transmission uniformity.

  1. Deep sea animal density and size estimated using a Dual-frequency IDentification SONar (DIDSON) offshore the island of Hawaii

    Science.gov (United States)

    Giorli, Giacomo; Drazen, Jeffrey C.; Neuheimer, Anna B.; Copeland, Adrienne; Au, Whitlow W. L.

    2018-01-01

    Pelagic animals that form deep sea scattering layers (DSLs) represent an important link in the food web between zooplankton and top predators. While estimating the composition, density and location of the DSL is important to understand mesopelagic ecosystem dynamics and to predict top predators' distribution, DSL composition and density are often estimated from trawls which may be biased in terms of extrusion, avoidance, and gear-associated biases. Instead, location and biomass of DSLs can be estimated from active acoustic techniques, though estimates are often in aggregate without regard to size or taxon specific information. For the first time in the open ocean, we used a DIDSON sonar to characterize the fauna in DSLs. Estimates of the numerical density and length of animals at different depths and locations along the Kona coast of the Island of Hawaii were determined. Data were collected below and inside the DSLs with the sonar mounted on a profiler. A total of 7068 animals were counted and sized. We estimated numerical densities ranging from 1 to 7 animals/m3 and individuals as long as 3 m were detected. These numerical densities were orders of magnitude higher than those estimated from trawls and average sizes of animals were much larger as well. A mixed model was used to characterize numerical density and length of animals as a function of deep sea layer sampled, location, time of day, and day of the year. Numerical density and length of animals varied by month, with numerical density also a function of depth. The DIDSON proved to be a good tool for open-ocean/deep-sea estimation of the numerical density and size of marine animals, especially larger ones. Further work is needed to understand how this methodology relates to estimates of volume backscatters obtained with standard echosounding techniques, density measures obtained with other sampling methodologies, and to precisely evaluate sampling biases.

  2. The effect of beam inclination on the performance of a passive vibration isolator using buckled beams

    International Nuclear Information System (INIS)

    Mori, H; Waters, T; Saotome, N; Nagamine, T; Sato, Y

    2016-01-01

    Passive vibration isolators are desired to have both high static stiffness to support large static load and low local stiffness to reduce the displacement transmissibility at frequencies greater than resonance. Utilization of a vertical buckled beam as a spring component is one way to realize such a stiffness characteristic since it exhibits a smaller ratio of local stiffness to static stiffness than that of a linear spring. This paper investigates the behaviour of a vibration isolator using inclined beams as well as vertical ones and examines the effect of beam inclination for the purpose of improving the isolation performance. The experimental system investigated has an isolated mass which is supported by a combination of two types of beams: buckled beams and constraining beams. The buckled beams can be inclined from the vertical by attachment devices, and the constraining beams are employed to prevent off-axis motion of the isolated mass. The results demonstrate that the inclination of the buckled beams reduces the resonance frequency and improves the displacement transmissibility at frequencies greater than resonance. (paper)

  3. Beam transport

    International Nuclear Information System (INIS)

    1988-01-01

    The beam diagnostic components for both the transfer and the high-energy beamlines perform well except for some of the scanners whose noise pick-up has become a problem, especially at low beam intensities. This noise pick-up is primarily due to deterioration of the bearings in the scanner. At some locations in the high-energy beamlines, scanners were replaced by harps as the scanners proved to be practically useless for the low-intensity beams required in the experimental areas. The slits in the low-energy beamline, which are not water-cooled, have to be repaired at regular intervals because of vacuum leaks. Overheating causes the ceramic feedthroughs to deteriorate resulting in the vacuum leaks. Water-cooled slits have been ordered to replace the existing slits which will later be used in the beamlines associated with the second injector cyclotron SPC2. The current-measurement system will be slightly modified and should then be much more reliable. 3 figs

  4. mos115_0403.TIF -- Multibeam backscatter sonar image for the nearshore Cape Flattery area: Data from survey effort HMPR-115-2004-03 in the Olympic Coast national marine sanctuary.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This multibeam backscatter sonar image of the sea floor (0-200 m water depths) was mosaiced from data collected fromvarious mapping efforts each October from...

  5. Simulations of the LEDA LEBT H+ beam

    International Nuclear Information System (INIS)

    Smith, H.V. Jr.; Sherman, J.D.; Stevens, R.R. Jr.; Young, L.M.

    1997-01-01

    The computer codes TRACE and SCHAR model the Low-Energy Demonstration Accelerator (LEDA) Low-Energy Beam Transport (LEBT) for 75-keV, 110-mA, dc H + beams. Solenoid-lens location studies verify that the proposed LEBT design gives a near-optimum match to the LEDA RFQ. The desired RFQ transmission (≥ 90%) and output emittance (≤ 0.22 π mm mrad, transverse) are obtained when PARMTEQM transports the file for the SCHAR-generated optimum beam through the RFQ

  6. Transmission dynamic range in chest radiology

    International Nuclear Information System (INIS)

    Lemmers, H.E.A.S.J.; Schultze Kool, L.J.; van Elburg, H.J.; Boelens, F.

    1989-01-01

    Due to the large difference in transmission between the lung area and the mediastinum, the human chest is a challenging object for radiographic imaging. This study is performed in order to define the dynamic range needed for a chest imaging chain. Eight hundred seventy-five consecutive outpatients were imaged with a prototype AMBER (advanced multiple beam equalization radiography) unit at 141 kVp. The equalization facility was disabled, allowing for the simultaneous capture of a film image and a digital dataset representing the local patient transmission in fields of approximately 2x2 cm. The datasets were analyzed to obtain the relation between the average transmission distribution in a subset of the population and physical parameters characterizing this subset, such as body weight or length

  7. Transmission Integration | Grid Modernization | NREL

    Science.gov (United States)

    Transmission Integration Transmission Integration The goal of NREL's transmission integration integration issues and provide data, analysis, and models to enable the electric power system to more and finding solutions to address them to enable transmission grid integration. Capabilities Power

  8. Characteristics of photon beams from Philips SL25 linear accelerators

    International Nuclear Information System (INIS)

    Palta, J.R.; Ayyangar, K.; Daftari, I.; Suntharalingam, N.

    1990-01-01

    The Philips SL25 accelerator is a multimodality machine offering asymmetric collimator jaws and a new type of beam bending and transport system. It produces photon beams, nominally at 6 and 25 MV, and a scattered electron beam with nine selectable energies between 4 and 22 MeV. Dosimetric characteristics for the 6- and 25-MV photon beams are presented with respect to field flatness, surface and depth dose characteristics, isodose distribution, field size factors for both open and wedged fields, and narrow beam transmission data in different materials

  9. Feasibility study for mega-electron-volt electron beam tomography.

    Science.gov (United States)

    Hampel, U; Bärtling, Y; Hoppe, D; Kuksanov, N; Fadeev, S; Salimov, R

    2012-09-01

    Electron beam tomography is a promising imaging modality for the study of fast technical processes. But for many technical objects of interest x rays of several hundreds of keV energy are required to achieve sufficient material penetration. In this article we report on a feasibility study for fast electron beam computed tomography with a 1 MeV electron beam. The experimental setup comprises an electrostatic accelerator with beam optics, transmission target, and a single x-ray detector. We employed an inverse fan-beam tomography approach with radiographic projections being generated from the linearly moving x-ray source. Angular projections were obtained by rotating the object.

  10. Series Transmission Line Transformer

    Science.gov (United States)

    Buckles, Robert A.; Booth, Rex; Yen, Boris T.

    2004-06-29

    A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

  11. Beam divergence scaling in neutral beam injectors

    International Nuclear Information System (INIS)

    Holmes, A.J.T.

    1976-01-01

    One of the main considerations in the design of neutral beam injectors is to monimize the divergence of the primary ion beam and hence maximize the beam transport and minimize the input of thermal gas. Experimental measurements of the divergence of a cylindrical ion beam are presented and these measurements are used to analyze the major components of ion beam divergence, namely: space charge expansion, gas-ion scattering, emittance and optical aberrations. The implication of these divergence components in the design of a neutral beam injector system is discussed and a method of maximizing the beam current is described for a given area of source plasma

  12. Drivers of Tuberculosis Transmission.

    Science.gov (United States)

    Mathema, Barun; Andrews, Jason R; Cohen, Ted; Borgdorff, Martien W; Behr, Marcel; Glynn, Judith R; Rustomjee, Roxana; Silk, Benjamin J; Wood, Robin

    2017-11-03

    Measuring tuberculosis transmission is exceedingly difficult, given the remarkable variability in the timing of clinical disease after Mycobacterium tuberculosis infection; incident disease can result from either a recent (ie, weeks to months) or a remote (ie, several years to decades) infection event. Although we cannot identify with certainty the timing and location of tuberculosis transmission for individuals, approaches for estimating the individual probability of recent transmission and for estimating the fraction of tuberculosis cases due to recent transmission in populations have been developed. Data used to estimate the probable burden of recent transmission include tuberculosis case notifications in young children and trends in tuberculin skin test and interferon γ-release assays. More recently, M. tuberculosis whole-genome sequencing has been used to estimate population levels of recent transmission, identify the distribution of specific strains within communities, and decipher chains of transmission among culture-positive tuberculosis cases. The factors that drive the transmission of tuberculosis in communities depend on the burden of prevalent tuberculosis; the ways in which individuals live, work, and interact (eg, congregate settings); and the capacity of healthcare and public health systems to identify and effectively treat individuals with infectious forms of tuberculosis. Here we provide an overview of these factors, describe tools for measurement of ongoing transmission, and highlight knowledge gaps that must be addressed. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  13. Dynamical chaos and beam-beam models

    International Nuclear Information System (INIS)

    Izrailev, F.M.

    1990-01-01

    Some aspects of the nonlinear dynamics of beam-beam interaction for simple one-dimensional and two-dimensional models of round and flat beams are discussed. The main attention is paid to the stochasticity threshold due to the overlapping of nonlinear resonances. The peculiarities of a round beam are investigated in view of using the round beams in storage rings to get high luminosity. 16 refs.; 7 figs

  14. Interaction of heavy ion beams with a hydrogen plasma: plasma lens effect and stopping power enhancement

    International Nuclear Information System (INIS)

    Gardes, D.; Bimbot, R.; Della-Negra, S.; Dumail, M.; Kubica, B.; Richard, A.; Rivet, M.F.; Servajean, A.; Deutsch, C.; Maynard, G.

    1988-01-01

    By coupling a hydrogen plasma to a Tandem accelerator, transmission and energy losses of 2 MeV/u carbon and sulfur beams passing through a plasma target have been investigated. Fluctuations in beam transmission have been observed and attributed to a plasma lens effect. Moreover, energy loss measurements indicate an enhanced stopping power of the plasma relative to its cold matter equivalent

  15. Micro computer aided beam transport for the SF cyclotron

    International Nuclear Information System (INIS)

    Honma, Toshihiro; Yamazaki, Tsutomu.

    1984-01-01

    An improvement of the beam transport system for the SF cyclotron is described. The system was designed to handle on-line alignment of the beam extracted from the SF cyclotron onto the optical axis of the transport line. It also enables to measure the beam emittance. The measurement of the emittance parameters is in particular necessary to calculate the beam optics. The calculation has been modified to become easy to handle. With the help of the computer-aided on-line beam profile measurement system, the operation of the beam transport system is very subservient to shorten the beam-tuning time and to improve the beam-transmission efficiency and the quality. (author)

  16. Initial alignment method for free space optics laser beam

    Science.gov (United States)

    Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi

    2016-08-01

    The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.

  17. Microwave energy transmission system for solar power station

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Hiroshi

    1988-05-05

    This paper deals with a microwave wireless energy transmission system which will be required for a solar power station under investigation, particularly, it describes its foundation and future investigation. It is supposed that for realization of microwave wireless transmission techniques, it is most important to investigate the effect of strong microwave beams on a plasma environment, establish control techniques for microwave beams in which a retro-directive system is combined with a computer control system, and develop a semiconductor transmission module. Institute of Space and Astronautical Science (Japan) made an experiment on the effect of microwaves on ionospheric plasma by using an observatory rocket. The institute has planned to make an experiment on a microwave energy transmission system which is to be mounted to a small-scale space flyer unit in order to examine the control of microwave beams and 10 KW power transmission, in addition to investigation on the interaction of microwave energy beams with a plasma environment. (4 figs, 3 tabs, 20 refs)

  18. Beam propagation

    International Nuclear Information System (INIS)

    Hermansson, B.R.

    1989-01-01

    The main part of this thesis consists of 15 published papers, in which the numerical Beam Propagating Method (BPM) is investigated, verified and used in a number of applications. In the introduction a derivation of the nonlinear Schroedinger equation is presented to connect the beginning of the soliton papers with Maxwell's equations including a nonlinear polarization. This thesis focuses on the wide use of the BPM for numerical simulations of propagating light and particle beams through different types of structures such as waveguides, fibers, tapers, Y-junctions, laser arrays and crystalline solids. We verify the BPM in the above listed problems against other numerical methods for example the Finite-element Method, perturbation methods and Runge-Kutta integration. Further, the BPM is shown to be a simple and effective way to numerically set up the Green's function in matrix form for periodic structures. The Green's function matrix can then be diagonalized with matrix methods yielding the eigensolutions of the structure. The BPM inherent transverse periodicity can be untied, if desired, by for example including an absorptive refractive index at the computational window edges. The interaction of two first-order soliton pulses is strongly dependent on the phase relationship between the individual solitons. When optical phase shift keying is used in coherent one-carrier wavelength communication, the fiber attenuation will suppress or delay the nonlinear instability. (orig.)

  19. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  20. Bulk sample self-attenuation correction by transmission measurement

    International Nuclear Information System (INIS)

    Parker, J.L.; Reilly, T.D.

    1976-01-01

    Various methods used in either finding or avoiding the attenuation correction in the passive γ-ray assay of bulk samples are reviewed. Detailed consideration is given to the transmission method, which involves experimental determination of the sample linear attenuation coefficient by measuring the transmission through the sample of a beam of gamma rays from an external source. The method was applied to box- and cylindrically-shaped samples

  1. Burial and exhumation of temperate bedrock reefs as elucidated by repetitive high-resolution sea floor sonar surveys: Spatial patterns and impacts to species' richness and diversity

    Science.gov (United States)

    Storlazzi, Curt D.; Fregoso, Theresa A.; Figurski, Jared D.; Freiwald, Jan; Lonhart, Steve I.; Finlayson, David P.

    2013-01-01

    To understand how chronic sediment burial and scour contribute to variation in the structure of algal and invertebrate communities on temperate bedrock reefs, the dynamics of the substrate and communities were monitored at locations that experience sand inundation and adjacent areas that do not. Co-located benthic scuba-transect surveys and high-resolution swath-sonar surveys were completed on bedrock reefs on the inner shelf of northern Monterey Bay, CA, in early winter 2009, spring 2010, and summer 2010. Analysis of the sonar surveys demonstrates that during the 8 months over which the surveys were conducted, 19.6% of the study area was buried by sand while erosion resulted in the exposure of bedrock over 13.8% of the study area; the remainder underwent no change between the surveys. Substrate classifications from the benthic transect surveys correlated with classifications generated from the sonar surveys, demonstrating the capacity of high-resolution sonar surveys to detect burial of bedrock reefs by sediment. On bedrock habitat that underwent burial and exhumation, species' diversity and richness of rock-associated sessile and mobile organisms were 50–66% lower as compared to adjacent stable bedrock habitat. While intermediate levels of disturbance can increase the diversity and richness of communities, these findings demonstrate that burial and exhumation of bedrock habitat are sources of severe disturbance. We suggest that substrate dynamics must be considered when developing predictions of benthic community distributions based on sea floor imagery. These results highlight the need for predictive models of substrate dynamics and for a better understanding of how burial and exhumation shape benthic communities.

  2. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    2012-01-01

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  3. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  4. Poverty and price transmission

    DEFF Research Database (Denmark)

    Elleby, Christian

    A key parameter determining the welfare impact from a world market shock is the transmission elasticity which measures the average domestic response to an international price change. Many studies have estimated price transmission elasticities for a large number of countries but the variation in t...

  5. Transmission market support system

    International Nuclear Information System (INIS)

    Reinschmidt, K.F.; Coles, B.C.

    1995-01-01

    An interactive, computer-based market support system has been developed for transmission access that is efficient, equitable, and fair to all parties concerned with electrical transmission: utilities, electric generators, owners of transmission networks, and wholesale purchasers of electrical power. Each participant transmits electronically to the computer system his proposed price schedule for buying, selling, or transmitting power for each future time period. The price for transmission on a single line in one direction can differ from the price in the other direction. The total quantity offered in the transmission bid represents the capacity of the line, and the flow on the line cannot exceed this value. The system automatically computes the prices that clear the market; that is, the price that each generator receives at each bus, the price that each transmission operator receives on each line, and the price that each customer pays at each bus. The computer system maximizes the benefits to all three classes while satisfying the electrical characteristics of the transmission system by means of load flow calculations. Customers never pay more than their bid prices (but may pay less), and generators and transmission operators never receive less than their bid prices (but may receive more). The price at each bus applies to all buyers and sellers at that bus: all buyers at the same bus pay the same price and all generators at a bus receive the same price

  6. Pricing transmission services

    International Nuclear Information System (INIS)

    Haaden, E.

    1995-01-01

    The price structure for transmission of electric power through the main lines in Sweden is analyzed. After deregulation of the electricity market, the main transmission lines are owned by a separate national company, with no interests from the power producers. Comparisons are made to ideal marginal price structures. 6 refs

  7. Eliminating Perinatal HIV Transmission

    Centers for Disease Control (CDC) Podcasts

    In this podcast, CDC’s Dr. Steve Nesheim discusses perinatal HIV transmission, including the importance of preventing HIV among women, preconception care, and timely HIV testing of the mother. Dr. Nesheim also introduces the revised curriculum Eliminating Perinatal HIV Transmission intended for faculty of OB/GYN and pediatric residents and nurse midwifery students.

  8. Electric transmission technology

    International Nuclear Information System (INIS)

    Shah, K.R.

    1990-01-01

    Electric transmission technology has matured and can transmit bulk power more reliably and economically than the technology 10 years ago.In 1882, Marcel Depres transmitted 15 kW electric power at 2 kV, using a constant direct current; present transmission voltages have risen to ± 600 kV direct current (DC) and 765 kV alternating current (AC), and it is now possible to transmit bulk electric power at voltages as high as ± 1000 kV DC and 1500 kV AC. Affordable computer systems are now available to optimize transmission reliably. New materials have reduced the bulk of insulation for lines and equipment. New conducting materials and configurations have reduced losses in transmission. Advances in line structures and conductor motion, understanding of flashover characteristics of insulators and air-gaps and electrical performance of lines have resulted in more compact urban transmission lines. (author). 15 refs., 7 tabs., 11 figs

  9. High gradient lens for charged particle beam

    Science.gov (United States)

    Chen, Yu-Jiuan

    2014-04-29

    Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

  10. Thrust generation experiments on microwave rocket with a beam concentrator for long distance wireless power feeding

    Science.gov (United States)

    Fukunari, Masafumi; Yamaguchi, Toshikazu; Nakamura, Yusuke; Komurasaki, Kimiya; Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Sakamoto, Keishi

    2018-04-01

    Experiments using a 1 MW-class gyrotron were conducted to examine a beamed energy propulsion rocket, a microwave rocket with a beam concentrator for long-distance wireless power feeding. The incident beam is transmitted from a beam transmission mirror system. The beam transmission mirror system expands the incident beam diameter to 240 mm to extend the Rayleigh length. The beam concentrator receives the beam and guides it into a 56-mm-diameter cylindrical thruster tube. Plasma ignition and ionization front propagation in the thruster were observed through an acrylic window using a fast-framing camera. Atmospheric air was used as a propellant. Thrust generation was achieved with the beam concentrator. The maximum thrust impulse was estimated as 71 mN s/pulse from a pressure history at the thrust wall at the input energy of 638 J/pulse. The corresponding momentum coupling coefficient, Cm was inferred as 204 N/MW.

  11. Simple beam profile monitor

    Energy Technology Data Exchange (ETDEWEB)

    Gelbart, W.; Johnson, R. R.; Abeysekera, B. [ASD Inc. Garden Bay, BC (Canada); Best Theratronics Ltd Ottawa Ontario (Canada); PharmaSpect Ltd., Burnaby BC (Canada)

    2012-12-19

    An inexpensive beam profile monitor is based on the well proven rotating wire method. The monitor can display beam position and shape in real time for particle beams of most energies and beam currents up to 200{mu}A. Beam shape, position cross-section and other parameters are displayed on a computer screen.

  12. Crystalline beams

    International Nuclear Information System (INIS)

    Schiffer, J.P.

    1989-01-01

    Ions in a storage ring are confined to a mean orbit by focusing elements. To a first approximation these may be described by a constant harmonic restoring force: F = -Kr. If the particles in the frame moving along with the beam have small random thermal energies, then they will occupy a cylindrical volume around the mean orbit and the focusing force will be balanced by that from the mutual repulsion of the particles. Inside the cylinder only residual two-particle interactions will play a significant role and some form of ordering might be expected to take place. The results of some of the first MD calculations showed a surprising result: not only were the particles arranged in the form of a tube, but they formed well-defined layers: concentric shells, with the particles in each shell arranged in a hexagonal lattice that is characteristic of two-dimensional Coulomb systems. This paper discusses the condense layer structure

  13. Analysis of Bending Waves in Phononic Crystal Beams with Defects

    Directory of Open Access Journals (Sweden)

    Yongqiang Guo

    2018-01-01

    Full Text Available Existing investigations on imperfect phononic crystal beams mainly concern periodic multi-span beams carrying either one or two channel waves with random or deterministic disorder in span-length. This paper studies the two channel bending waves in phononic crystal beams consisting of many phases of materials with defects introduced as one structural segment having different cross-sectional dimensions or material parameters. The method of reverberation-ray matrix (MRRM based on the Timoshenko beam theory, which can conduct high-frequency analysis, is extended for the theoretical analysis of dispersion and transmission of bending waves. The supercell technique and the Floquet–Bloch theorem are adopted for modeling the dispersion characteristics, and the whole finite structural model is used to calculate the transmission spectra. Experimental measurements and numerical calculations are provided to validate the displacement transmission obtained by the proposed MRRM, with the effect of damping on transmission spectra being concerned. The high-frequency calculation applicability of the proposed MRRM is also confirmed by comparing the present results with the corresponding ones either using the transfer matrix method (TMM or MRRM based on Euler—Bernoulli beam theory. The influences of defect size, defect form, and unit-cell number on the transmission spectra and the band structures are discussed. The drawn conclusions may be useful for designing or evaluating the defected phononic crystal beams in bending wave control. In addition, our conclusions are especially potential for identifying the defect location through bending wave signals.

  14. Beam-Beam Interaction Studies at LHC

    CERN Document Server

    Schaumann, Michaela; Alemany Fernandez, R

    2011-01-01

    The beam-beam force is one of the most important limiting factors in the performance of a collider, mainly in the delivered luminosity. Therefore, it is essential to measure the effects in LHC. Moreover, adequate understanding of LHC beam-beam interaction is of crucial importance in the design phases of the LHC luminosity upgrade. Due to the complexity of this topic the work presented in this thesis concentrates on the beam-beam tune shift and orbit effects. The study of the Linear Coherent Beam-Beam Parameter at the LHC has been determined with head-on collisions with small number of bunches at injection energy (450 GeV). For high bunch intensities the beam-beam force is strong enough to expect orbit effects if the two beams do not collide head-on but with a crossing angle or with a given offset. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the beam-beam force becomes more and more important has been studied and the results are as well ...

  15. Cost characteristics of transmission

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    FERC regulation of transmission is predicated, at least in part, on a belief that, in the absence of regulation, some utilities would be able to exercise monopoly power and the ability to extract monopoly profits. This monopoly power follows from the view that transmission facilities inevitably are a natural monopoly for both economic and social/regulatory reasons. In the first part of this section the authors present the argument that transmission is a natural monopoly. They then consider the impact of this on regulation and the problems that that view creates

  16. Understanding Ebola Virus Transmission

    Directory of Open Access Journals (Sweden)

    Seth Judson

    2015-02-01

    Full Text Available An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus.

  17. Beam-dump kicker magnets

    International Nuclear Information System (INIS)

    Bulos, F.; Odian, A.; Tomlin, B.

    1983-01-01

    The beam-dump kicker magnets are located in the final focus region and, in conjunction with septum magnets, extract the beams after they have passed the interaction point (IP) and direct them to their respective dumps. Two schemes for these kickers have been under consideration; ferrite transmission line magnets utilizing technology common with damping rings and positron target kickers, and current loop magnets which are possible only for the dump kickers, where the rise time of the magnetic pulse can be comparatively longer; approximately 400 nanoseconds as compared with 50 nanoseconds for the others. A prototype ferrite kicker has been built and is undergoing tests. Since the current loop requires lower voltage and power plus some additional savings in cost, we decided to build and test a prototype. This note describes in detail an optimized design for the current loop magnets and their associated pulse circuitry

  18. Environmental effects on underwater optical transmission

    Science.gov (United States)

    Chu, Peter C.; Breshears, Brian F.; Cullen, Alexander J.; Hammerer, Ross F.; Martinez, Ramon P.; Phung, Thai Q.; Margolina, Tetyana; Fan, Chenwu

    2017-05-01

    Optical communication/detection systems have potential to get around some limitations of current acoustic communications and detection systems especially increased fleet and port security in noisy littoral waters. Identification of environmental effects on underwater optical transmission is the key to the success of using optics for underwater communication and detection. This paper is to answer the question "What are the transfer and correlation functions that relate measurements of hydrographic to optical parameters?" Hydrographic and optical data have been collected from the Naval Oceanographic Office survey ships with the High Intake Defined Excitation (HIDEX) photometer and sea gliders with optical back scattering sensor in various Navy interested areas such as the Arabian Gulf, Gulf of Oman, east Asian marginal seas, and Adriatic Sea. The data include temperature, salinity, bioluminescence, chlorophyll-a fluorescence, transmissivity at two different wavelengths (TRed at 670 nm, TBlue at 490 nm), and back scattering coefficient (bRed at 700 nm, bBlue at 470 nm). Transfer and correlation functions between the hydrographic and optical parameters are obtained. Bioluminescence and fluorescence maxima, transmissivity minimum with their corresponding depths, red and blue laser beam peak attenuation coefficients are identified from the optical profiles. Evident correlations are found between the ocean mixed layer depth and the blue and red laser beam peak attenuation coefficients, bioluminescence and fluorescence maxima in the Adriatic Sea, Arabian Gulf, Gulf of Oman, and Philippine Sea. Based on the observational data, an effective algorithm is recommended for solving the radiative transfer equation (RTE) for predicting underwater laser radiance.

  19. Transmission electron microscope sample holder with optical features

    Science.gov (United States)

    Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  20. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    Wangler, T.P.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  1. Beam-beam issues in asymmetric colliders

    International Nuclear Information System (INIS)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e + - e - colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II)

  2. Cryo-transmission electron microscopy of Ag nanoparticles grown on an ionic liquid substrate

    KAUST Repository

    Anjum, Dalaver H.; Stiger, Rebecca M.; Finley, James J.; Conway, James F.

    2010-01-01

    We report a novel method of growing silver nanostructures by cathodic sputtering onto an ionic liquid (IL) and our visualization by transmission cryo-electron microscopy to avoid beam-induced motion of the nanoparticles. By freezing the IL

  3. Transmissions in vehicles 2010

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Within the international VDI congress 'Gears in vehicles 2010' of the VDI Wissensforum GmbH (Duesseldorf, Federal Republic of Germany) between 22nd and 23rd June, 2010, in Friedrichshafen (Federal Republic of Germany), the following lectures were held: (1) 8HP70H - The moldhybrid transmission from ZF - Cjallenges and achievements (P. Gutmann); (2) GETRAG boosted range extender - A highly flexible electric powertrain for maximum CO{sub 2} reduction (S. Huepkes); (3) E-Transmission between full-hybrid and E-drive (P. Tenberge); (4) Reducing NO{sub x} and particulate emissions in electrified drivelines (R. Kuberczyk); (5) Simulation aided HEV and EV development: from the component to the whole powertrain (A. Gacometti); (6) Investigations on operating behaviour of the optimized CVT hybrid driveline (B.-R. Hoehn); (7) Customer-oriented dimensioning of electrified drivetrains (M. Eghtessad); (8) Decentralized optimal control strategy for parallel hybrid electric vehicles (A. Frenkel); (9) The new generation 6-speed automatic transmission AF40 (G. Bednarek); (10) Customized mechatronic solutions for integrated transmission control units (M. Wieczorek); (11) The optimal automatic transmission for front-transverse applications - Planetary transmissions or dual clutch transmissions? (G. Gumpoltsberger); (12) The new shift-by-wire gearshift lever for the Audi A8 - Requirements and concept (T. Guttenbergere); (13) The new shift-by-wire gearshift lever for the Audi A8 - Realization (A. Giefer); (14) Fuel-efficient transmissions of the future: Calculation of the efficiency factor for vehicle transmissions (B. Volpert); (15) HT-ACM: A new polymer generation for static and dynamic gearbox sealing solutions (E. Osen); (16) 'Energy efficiency equipped solutions by SKF' for power train applications - A contribution to CO{sub 2} - emission reduction and sustainability (T. Bobke); (17) 6-Ratio planetary shift transmission controlled by 4 external brakes, and design

  4. Evidence of mud diapirism and coral colonies in the ionian sea (central mediterranean from high resolution chirp sonar survey

    Directory of Open Access Journals (Sweden)

    C. Corselli

    2006-06-01

    Full Text Available A chirp sonar survey in the Ionian Sea investigated the Calabrian margin, the Calabrian accretionary wedge, the Taranto Trench and the Apulian foreland. Shallow tectonics structures have been related to deeper ones, recognised on CROP seismic profiles. The identified echo characters have been compared with those described in the modern literature and have been related to different kinds of sediments, on the basis of core samples. Based on echo character and morphology we have recognised: 1 A widespread presence of mounds, up to 50 m high, occurring on the Apulian plateau as isolated mounds in the deepest zones (1600-800 m and in groups in the shallower ones (800-600 m; they have been interpreted as coral mounds, according to a recent discovery of living deep water coral colonies in this zone. 2 Some mud diapirs, isolated or in groups of two or three elements, widespread in the whole study area. In analogy of what has been observed on the Mediterranean Ridge, their presence suggests the activity of deep tectonic structures (thrusts and faults and a reduced thickness (or absence of Messinian evaporites in this part of the Ionian Sea.

  5. Mapping the Gulf of Maine with side-scan sonar: A new bottom-type classification for complex seafloors

    Science.gov (United States)

    Barnhardt, W.A.; Kelley, J.T.; Dickson, S.M.; Belknap, D.F.

    1998-01-01

    The bedrock-framed seafloor in the northwestern Gulf of Maine is characterized by extreme changes in bathymetric relief and covered with a wide variety of surficial materials. Traditional methods of mapping cannot accurately represent the great heterogeneity of such a glaciated region. A new mapping scheme for complex seafloors, based primarily on the interpretation of side-scan sonar imagery, utilizes four easily recognized units: rock, gravel, sand and mud. In many places, however, the seafloor exhibits a complicated mixture or extremely 'patchy' distribution of the four basic units, which are too small to map individually. Twelve composite units, each a two-component mixture of the basic units, were established to represent this patchiness at a small scale (1:100,000). Using a geographic information system, these and all other available data (seismic profiles, grab samples, submersible dives and cores) were referenced to a common geographic base, superimposed on bathymetric contours and then integrated into surficial geologic maps of the regional inner continental shelf. This digital representation of the seafloor comprises a multidimensional, interactive model complete with explicit attributes (depth, bottom type) that allow for detailed analysis of marine environments.

  6. Modal Analysis of 27 mm Piezo Electric Plate for Small-Scale Underwater Sonar-Based Navigation

    Directory of Open Access Journals (Sweden)

    M. O. Afolayan

    2013-01-01

    Full Text Available This work presents progress towards the development of a small-scale, purely sonar-based navigation device for a robotic fish (~394 mm long. Aperture overloading of small (5 mm diameter ultrasonic transmitters does not allow them to be used effectively inside water. A test on a 27 mm diameter buzzer piezo plate shows promising performance under water at frequencies from 4.5 kHz to 80 kHz. ANSYS-based simulation was therefore used to find modal frequencies at higher frequencies so as to optimize this encouraging result. The simulation process also discovered several antiresonant frequencies such as 38.5 kHz, 54 kHz, and 57.5 kHz. All frequencies above the 8th harmonic (10,589.02 Hz are out of phase with the input load except a resonance frequency of 42.5 kHz and an antiresonance frequency of 56.5 kHz. Also, the first harmonic (1,648.73 Hz is the only frequency that gave a nodal deformation.

  7. Transmission issues in Alberta

    International Nuclear Information System (INIS)

    Levson, D.

    2002-01-01

    This paper outlined the major issues and concerns facing users of the transmission system in Alberta. They include congestion management issues that make investors uncertain about power generation. It is necessary to know the difference between which transmission price signals will be faced by low cost cogeneration at Fort McMurray and Cold Lake coal-fired generation near Edmonton compared to combined cycle gas generation near Calgary. Import and export policy tariffs are another concern. Most new generation opportunities in Alberta require access to export markets, but transmission facilities for export need policy support and appropriate tariffs. It was noted that the past actions of Alberta's Transmission Administrator and balancing pool may be distorting market signals for ancillary service markets, and that loss studies and calculations need upgrading

  8. Kansas Electric Transmission Lines

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set is a digital representation of the EletcircTransmission lines for the State of Kansas as maintained by the Kansas Corporation Commission. Data is...

  9. ECRH transmission system

    International Nuclear Information System (INIS)

    Tancredi, J.

    1983-01-01

    Hughes, Electron Dynamics Division is developing gyrotrons for ECRH requirements. In the development program, techniques have been evolved for transmission system components. These techniques include over-moded waveguide tapers, high average power windows, and rf water loads for testing

  10. Electric Power Transmission Lines

    Data.gov (United States)

    Department of Homeland Security — Transmission Lines are the system of structures, wires, insulators and associated hardware that carry electric energy from one point to another in an electric power...

  11. Bragg reflection transmission filters for variable resolution monochromators

    International Nuclear Information System (INIS)

    Chapman, D.

    1989-01-01

    There are various methods for improving the angular and spectral resolution of monochromator and analyzer systems. The novel system described here, though limited to higher x-ray energies (>20keV), is based on a dynamical effect occurring on the transmitted beam with a thin perfect crystal plate set in the Bragg reflection case. In the case of Bragg reflection from a perfect crystal, the incident beam is rapidly attenuated as it penetrates the crystal in the range of reflection. This extinction length is of the order of microns. The attenuation length, which determines the amount of normal transmission through the plate is generally much longer. Thus, in the range of the Bragg reflection the attenuation of the transmitted beam can change by several orders of magnitude with a small change in energy or angle. This thin crystal plate cuts a notch in the transmitted beam with a width equal to its Darwin width, thus acting as a transmission filter. When used in a non-dispersive mode with other monochromator crystals, the filter when set at the Bragg angle will reflect the entire Darwin width of the incident beam and transmit the wings of the incident beam distribution. When the element is offset in angle by some fraction of the Darwin width, the filter becomes useful in adjusting the angular width of the transmitted beam and removing a wing. Used in pairs with a symmetric offset, the filters can be used to continuously adjust the intrinsic angular divergence of the beam with good wing reduction. Instances where such filters may be useful are in improving the angular resolution of a small angle scattering camera. These filters may be added to a Bonse-Hart camera with one pair on the incident beam to reduce the intrinsic beam divergence and a second pair on the analyzer arm to improve the analyzer resolution. 2 refs., 3 Figs

  12. High precision electron beam diagnostic system for high current long pulse beams

    International Nuclear Information System (INIS)

    Chen, Y J; Fessenden, T; Holmes, C; Nelson, S D; Selchow, N.

    1999-01-01

    As part of the effort to develop a multi-axis electron beam transport system using stripline kicker technology for DARHT II applications, it is necessary to precisely determine the position and extent of long high energy beams (6-40 MeV, 1-4 kA, 2 microseconds) for accurate position control. The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (<20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt measurements performed using capacitive pick-off probes. Likewise, transmission line traveling wave probes have problems with multi-bounce effects due to these longer pulse widths. Finally, the high energy densities experienced in these applications distort typical foil beam position measurements

  13. Influence of laser beam profile on electromagnetically induced absorption

    International Nuclear Information System (INIS)

    Cuk, S. M.; Radonjic, M.; Krmpot, A. J.; Nikolic, S. N.; Grujic, Z. D.; Jelenkovic, B. M.

    2010-01-01

    We compared, experimentally and theoretically, Hanle electromagnetically induced absorption (EIA) obtained using Gaussian and Π-shaped laser beams 3 mm in diameter. The study was done by measuring the transmission of a laser locked to the F g =2→F e =3 transition at the D 2 line of 87 Rb in a vacuum cell. EIA linewidths obtained for the two laser profiles were significantly different in the range of laser intensities 1-4 mW/cm 2 . EIA with the Π-shaped laser beam has a broad intensity maximum and linewidths larger than those obtained with the Gaussian beam profile. We also studied Hanle EIA by measuring the transmission of selected segments of the entire laser beam by placing a small movable aperture in front of the detector. Waveforms so obtained in Hanle EIA resonances were strongly influenced both by the radial distance of the transmitted segment from the beam center and by the radial profile of the laser beam. We show that outer regions of Gaussian beam, and central regions of the Π-shaped beam generate the narrowest lines. The different behaviors of EIA owing to different beam profiles revealed by both theory and experiment indicate the importance of the radial profile of the laser beam for proper modeling of coherent effects in alkali metal vapors.

  14. Airspace: Antarctic Sound Transmission

    OpenAIRE

    Polli, Andrea

    2009-01-01

    This paper investigates how sound transmission can contribute to the public understanding of climate change within the context of the Poles. How have such transmission-based projects developed specifically in the Arctic and Antarctic, and how do these works create alternative pathways in order to help audiences better understand climate change? The author has created the media project Sonic Antarctica from a personal experience of the Antarctic. The work combines soundscape recordings and son...

  15. Offshore Transmission Technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-10-15

    The purpose of this document is to give an overview of offshore electricity transmission technologies. In particular this document is concerned with the use of High Voltage Direct Current (HVDC) systems and more specifically with the development of Voltage Source Converter (VSC) technology. This report outlines the current state of the main technology groups required for offshore HVDC transmission as well as giving examples of offshore projects (both current and future). Finally some indications of likely unit costs for HV assets are given.

  16. Eliminating Perinatal HIV Transmission

    Centers for Disease Control (CDC) Podcasts

    2012-11-26

    In this podcast, CDC’s Dr. Steve Nesheim discusses perinatal HIV transmission, including the importance of preventing HIV among women, preconception care, and timely HIV testing of the mother. Dr. Nesheim also introduces the revised curriculum Eliminating Perinatal HIV Transmission intended for faculty of OB/GYN and pediatric residents and nurse midwifery students.  Created: 11/26/2012 by Division of HIV/AIDS Prevention.   Date Released: 11/26/2012.

  17. Coverage Extension via Side-Lobe Transmission in Multibeam Satellite System

    OpenAIRE

    Gharanjik, Ahmad; Kmieciak, Jarek; Shankar, Bhavani; Ottersten, Björn

    2017-01-01

    In this paper, we study feasibility of coverage extension of a multibeam satellite network by providing low-rate communications to terminals located outside the coverage of main beams. Focusing on the MEO satellite network, and using realistic link budgets from O3b networks, we investigate the performance of both forward and return-links for terminals stationed in the side lobes of the main beams. Particularly, multi-carrier transmission for forward-link and single carrier transmission for re...

  18. Real time neutral beam power control on MAST

    Energy Technology Data Exchange (ETDEWEB)

    Homfray, David A., E-mail: david.homfray@ccfe.ac.uk [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Benn, A.; Ciric, D.; Day, I.; Dunkley, V.; Keeling, D.; Khilar, S.; King, D.; King, R. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Kurutz, U. [Department of Experimental Plasma Physics, University of Augsburg, Augsburg (Germany); Payne, D.; Simmonds, M.; Stevenson, P.; Tame, C. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon (United Kingdom)

    2011-10-15

    Real time power control of neutral beam provides an excellent tool for many different plasma physics studies. Power control at a better resolution than the level of a single injector is usually achieved by modulating individual power supplies. However, the short beam slowing down time on MAST is such that the plasma would be sensitive to modulating the neutral beam using this 100% on-off pulse-width modulation method. A novel alternative method of power control has been demonstrated, where the arc current, and hence beam current, has been controlled in real time allowing variations in neutral beam power. This has been demonstrated in a MAST plasma with almost no loss of transmission as a consequence of the optical properties of the high perveance MAST neutral beam system. This paper will detail the methodology, experiment and results and discuss the full implementation of this method that will allow MAST to control the beam power in real time.

  19. Linac4 Low Energy Beam Measurements with Negative Hydrogen

    CERN Document Server

    Scrivens, R; Crettiez, O; Dimov, V; Gerard, D; Granemann Souza, E; Guida, R; Hansen, J; Lallement, J B; Lettry, J; Lombardi, A; Midttun, O; Pasquino, C; Raich, U; Riffaud, B; Roncarolo, F; Valerio-Lizarraga, C A; Wallner, J; Yarmohammadi Satri, M; Zickler, T

    2014-01-01

    Linac4, a 160 MeV normal-conducting H- linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H- beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  20. Neutral beam injection optimization at TJ-II

    International Nuclear Information System (INIS)

    Fuentes, C.; Liniers, M.; Wolfers, G.; Alonso, J.; Marcon, G.; Carrasco, R.; Guasp, J.; Acedo, M.; Sanchez, E.; Medrano, M.; Garcia, A.; Doncel, J.; Alejaldre, C.; Tsai, C.C.; Barber, G.; Sparks, D.

    2005-01-01

    Neutral beam injection (NBI) heating has been used on the TJ-II stellarator for the first time. The beam has a port-through power between 200 and 400 kW and injection energy 28 kV. Beam transmission is limited by beam interception at the injection port and the first toroidal field coil, therefore, beam steering optimization is of critical importance. The beam interaction areas inside TJ-II vacuum chamber are surveyed by infrared thermography. Beam reionization can be a problem due to the presence of residual gas in the duct region. Halpha emission is used to monitor the reionization at the duct. A careful optimization of the injected gas has been carried out

  1. Linac4 low energy beam measurements with negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Scrivens, R., E-mail: richard.scrivens@cern.ch; Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T. [CERN, 1211 Geneva 23 (Switzerland)

    2014-02-15

    Linac4, a 160 MeV normal-conducting H{sup −} linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H{sup −} beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  2. Optical analog transmission device

    International Nuclear Information System (INIS)

    Ikawa, Shinji.

    1994-01-01

    The present invention concerns a device such as electro-optical conversion elements, optoelectric-electric elements and optical transmission channel, not undergoing deleterious effects on the efficiency of conversion and transmission due to temperature, and aging change. That is, a sine wave superposing means superposes, on a detector signal to be transmitted, a sine-wave signal having a predetermined amplitude and at a frequency lower than that of the detector signal. An optoelectric conversion means converts the electric signal as the signal of the sine-wave signal superposing means into an optical signal and outputs the same to an optical transmitting channel. The optoelectric conversion means converts the transmitted signal to an electric signal. A discriminating means discriminates the electric signal into a detector signal and a sine-wave signal. A calculating means calculates an optical transmitting efficiency of the transmitting channel based on the amplitude of the discriminated sine-wave signal. A processing means compensates an amplitude value of the detector signals discriminated by the discriminating means based on the optical transmission efficiency. As a result, an optical analog transmission device can be attained, which conducts optical transmission at a high accuracy without undergoing the defective effects of the optical transmission efficiency. (I.S.)

  3. National transmission grid study

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Spencer [USDOE Office of the Secretary of Energy, Washington, DC (United States)

    2003-05-31

    The National Energy Policy Plan directed the U.S. Department of Energy (DOE) to conduct a study to examine the benefits of establishing a national electricity transmission grid and to identify transmission bottlenecks and measures to address them. DOE began by conducting an independent analysis of U.S. electricity markets and identifying transmission system bottlenecks using DOE’s Policy Office Electricity Modeling System (POEMS). DOE’s analysis, presented in Section 2, confirms the central role of the nation’s transmission system in lowering costs to consumers through increased trade. More importantly, DOE’s analysis also confirms the results of previous studies, which show that transmission bottlenecks and related transmission system market practices are adding hundreds of millions of dollars to consumers’ electricity bills each year. A more detailed technical overview of the use of POEMS is provided in Appendix A. DOE led an extensive, open, public input process and heard a wide range of comments and recommendations that have all been considered.1 More than 150 participants registered for three public workshops held in Detroit, MI (September 24, 2001); Atlanta, GA (September 26, 2001); and Phoenix, AZ (September 28, 2001).

  4. LINAC4 low energy beam measurements

    CERN Document Server

    Hein, L M; Lallement, J B; Lombardi, A M; Midttun, O; Posocco, P; Scrivens, R

    2012-01-01

    Linac4 is a 160 MeV normal-conducting linear accelerator for negative Hydrogen ions (H−), which will replace the 50 MeV proton Linac (Linac2) as linear injector for the CERN accelerators. The low energy part, comprising a 45 keV Low Energy Beam Transport system (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) is being assembled in a dedicated test stand for pre-commissioning with a proton beam. During 2011 extensive measurements were done after the source and after the LEBT with the aim of preparing the RFQ commissioning and validating the simulation tools, indispensable for future source upgrades. The measurements have been thoroughly simulated with a multi-particle code, including 2D magnetic field maps, error studies, steering studies and the generation of beam distribution from measurements. Emittance, acceptance and transmission measurements will be presented and compared to the results of the simulations.

  5. Recent DIII-D neutral beam calibration results

    International Nuclear Information System (INIS)

    Wight, J.; Hong, R.M.; Phillips, J.

    1991-10-01

    Injected DIII-D neutral beam power is estimated based on three principle quantities: the fraction of ion beam that is neutralized in the neutralizer gas cell, the beamline transmission efficiency, and the fraction of beam reionized in the drift duct. System changes in the past few years have included a new gradient grid voltage operating point, ion source arc regulation, routine deuterium operations and new neutralizer gas flow controllers. Additionally, beam diagnostics have been improved and better calibrated. To properly characterize the beams the principle quantities have been re-measured. Two diagnostics are primarily used to measure the quantities. The beamline waterflow calorimetry system measures the neutralization efficiency and the beamline transmission efficiency, and the target tile thermocouples measure the reionization loss. An additional diagnostic, the target tile pyrometer, confirmed the reionization loss measurement. Descriptions and results of these measurements will be presented. 4 refs., 5 figs., 2 tabs

  6. Experimental investigation of complex circular Airy beam characteristics

    Science.gov (United States)

    Porfirev, A. P.; Fomchenkov, S. A.; Khonina, S. N.

    2018-04-01

    We demonstrate a new type of circular Airy beams, the so-called azimuthally modulated circular Airy beams, generated by utilizing a diffraction element, whose transmission function is the sum of the transmission function of the element generating a "petal" pattern and the transmission function of the element generating a circular Airy beam. We experimentally investigate the propagation dynamics of such beams and demonstrate that their autofocusing and selfhealing properties are strongly dependent on the number of generated petals. These beams are a combination of a conventional circular Airy beam and vortex laser beams (or their superpositions). Using a spatial light modulator, we demonstrate that these beams have unique properties such as autofocusing, "nondiffractive" propagation and self-healing after passing through an obstacle. The experimental results are in good agreement with the simulation. We believe that these results can be very useful for lensless laser fabrication and laser manipulation techniques, as well as for development of new filament plasma multi-channel formation methods.

  7. Wireless data signal transmission system

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver.......The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver....

  8. Dynamics of the off axis intense beam propagation in a spiral inflector

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, A., E-mail: animesh@vecc.gov.in; Sing Babu, P., E-mail: psb@vecc.gov.in; Pandit, V.S., E-mail: pandit@vecc.gov.in

    2017-01-01

    In this paper the dynamics of space charge dominated beam in a spiral inflector is discussed by developing equations of motion for centroid and beam envelope for the off axis beam propagation. Evolution of the beam centroid and beam envelope is studied as a function of the beam current for various input beam parameters. The transmission of beam through the inflector is also estimated as a function of the beam current for an on axis and off axis beam by tracking a large number of particles. Simulation studies show that shift of the centroid from the axis at the inflector entrance affects the centroid location at the exit of the inflector and causes reduction in the beam transmission. The centroid shift at the entrance in the horizontal plane (h plane) is more critical as it affects the centroid shift in the vertical plane (u plane) by a large amount near the inflector exit where the available aperture is small. The beam transmission is found to reduce with increase in the centroid shift as well as with the beam current.

  9. A symplectic coherent beam-beam model

    International Nuclear Information System (INIS)

    Furman, M.A.

    1989-05-01

    We consider a simple one-dimensional model to study the effects of the beam-beam force on the coherent dynamics of colliding beams. The key ingredient is a linearized beam-beam kick. We study only the quadrupole modes, with the dynamical variables being the 2nd-order moments of the canonical variables q, p. Our model is self-consistent in the sense that no higher order moments are generated by the linearized beam-beam kicks, and that the only source of violation of symplecticity is the radiation. We discuss the round beam case only, in which vertical and horizontal quantities are assumed to be equal (though they may be different in the two beams). Depending on the values of the tune and beam intensity, we observe steady states in which otherwise identical bunches have sizes that are equal, or unequal, or periodic, or behave chaotically from turn to turn. Possible implications of luminosity saturation with increasing beam intensity are discussed. Finally, we present some preliminary applications to an asymmetric collider. 8 refs., 8 figs

  10. Antihydrogen Beams

    Science.gov (United States)

    Yamazaki, Yasunori; Doser, Michael; Pérez, Patrice

    2018-03-01

    Why does our universe consist purely of matter, even though the same amount of antimatter and matter should have been produced at the moment of the Big Bang 13.8 billion years ago? One of the most potentially fruitful approaches to address the mystery is to study the properties of antihydrogen and antiprotons. Because they are both stable, we can in principle make measurement precision as high as we need to see differences between these antimatter systems and their matter counterparts, i.e. hydrogen and protons. This is the goal of cold antihydrogen research. To study a fundamental symmetry-charge, parity, and time reversal (CPT) symmetry-which should lead to identical spectra in hydrogen and antihydrogen, as well as the weak equivalence principle (WEP), cold antihydrogen research seeks any discrepancies between matter and antimatter, which might also offer clues to the missing antimatter mystery. Precision tests of CPT have already been carried out in other systems, but antihydrogen spectroscopy offers the hope of reaching even higher sensitivity to violations of CPT. Meanwhile, utilizing the Earth and antihydrogen atoms as an experimental system, the WEP predicts a gravitational interaction between matter and antimatter that is identical to that between any two matter objects. The WEP has been tested to very high precision for a range of material compositions, but no such precision test using antimatter has yet been carried out, offering hope of a telltale inconsistency between matter and antimatter. In this Discovery book, we invite you to visit the frontiers of cold antimatter research, focusing on new technologies to form beams of antihydrogen atoms and antihydrogen ions, and new ways of interrogating the properties of antimatter.

  11. Beam Techniques - Beam Control and Manipulation

    International Nuclear Information System (INIS)

    Minty, Michiko G

    2003-01-01

    We describe commonly used strategies for the control of charged particle beams and the manipulation of their properties. Emphasis is placed on relativistic beams in linear accelerators and storage rings. After a brief review of linear optics, we discuss basic and advanced beam control techniques, such as transverse and longitudinal lattice diagnostics, matching, orbit correction and steering, beam-based alignment, and linac emittance preservation. A variety of methods for the manipulation of particle beam properties are also presented, for instance, bunch length and energy compression, bunch rotation, changes to the damping partition number, and beam collimation. The different procedures are illustrated by examples from various accelerators. Special topics include injection and extraction methods, beam cooling, spin transport and polarization

  12. Beam Techniques - Beam Control and Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Minty, Michiko G

    2003-04-24

    We describe commonly used strategies for the control of charged particle beams and the manipulation of their properties. Emphasis is placed on relativistic beams in linear accelerators and storage rings. After a brief review of linear optics, we discuss basic and advanced beam control techniques, such as transverse and longitudinal lattice diagnostics, matching, orbit correction and steering, beam-based alignment, and linac emittance preservation. A variety of methods for the manipulation of particle beam properties are also presented, for instance, bunch length and energy compression, bunch rotation, changes to the damping partition number, and beam collimation. The different procedures are illustrated by examples from various accelerators. Special topics include injection and extraction methods, beam cooling, spin transport and polarization.

  13. Literature in Focus Beta Beams: Neutrino Beams

    CERN Document Server

    2009-01-01

    By Mats Lindroos (CERN) and Mauro Mezzetto (INFN Padova, Italy) Imperial Press, 2009 The beta-beam concept for the generation of electron neutrino beams was first proposed by Piero Zucchelli in 2002. The idea created quite a stir, challenging the idea that intense neutrino beams only could be produced from the decay of pions or muons in classical neutrino beams facilities or in future neutrino factories. The concept initially struggled to make an impact but the hard work by many machine physicists, phenomenologists and theoreticians over the last five years has won the beta-beam a well-earned position as one of the frontrunners for a possible future world laboratory for high intensity neutrino oscillation physics. This is the first complete monograph on the beta-beam concept. The book describes both technical aspects and experimental aspects of the beta-beam, providing students and scientists with an insight into the possibilities o...

  14. PLT and Doublet III neutral beam injection systems

    International Nuclear Information System (INIS)

    Haselton, H.H.; Dagenhart, W.K.; Schechter, D.E.; Stewart, L.D.; Stirling, W.L.

    1976-01-01

    The design program is being supported by experimental work with all beam line components: gas cells, bending magnets, beam stops, magnetic shielding, and high speed-high throughput cryopumping systems. Stray toroidal fields and fields produced by external transmission or mirror magnets are under study to determine the optimum means of removing the unneutralized component from the beam. Concepts utilizing materials with high permeability are adequate to provide the source with the necessary magnetic shielding. Beam stops capable of dissipating a power density of 10 to 40 kW/cm 2 are required for ion dumps, diagnostics, and on line ion source conditioning

  15. Neutron transmission and reflection at a copper single crystal

    International Nuclear Information System (INIS)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Fayek, M.; Habib, N.; Wahba, M.

    1991-01-01

    Neutron transmission and reflection at a copper single crystal cut along the (111) plane were studied with the fixed-scattering-angle spectrometer installed at the ET-RR-1 reactor. The transmission was measured for neutron wavelengths between 0.15 and 0.46 nm and various orientations of the (111) plane with respect to the incident beam. When used as a neutron band pass filter, the crystal is optimally oriented when the neutron beam is incident parallel to the [111] direction. The reflectivity was measured for the (111) plane at 45deg with respect to the incident beam. The results were found to be in reasonable agreement with a value predicted for the reflected intensity at an imperfect crystal with finite absorption. (orig.) [de

  16. Neutron transmission and reflection at a copper single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Fayek, M.; Habib, N. (Atomic Energy Establishment, Cairo (Egypt). Reactor and Neutron Physics Dept.); Wahba, M. (Ain Shams Univ., Cairo (Egypt). Dept. of Engineering Physics and Mathematics)

    1991-06-01

    Neutron transmission and reflection at a copper single crystal cut along the (111) plane were studied with the fixed-scattering-angle spectrometer installed at the ET-RR-1 reactor. The transmission was measured for neutron wavelengths between 0.15 and 0.46 nm and various orientations of the (111) plane with respect to the incident beam. When used as a neutron band pass filter, the crystal is optimally oriented when the neutron beam is incident parallel to the (111) direction. The reflectivity was measured for the (111) plane at 45deg with respect to the incident beam. The results were found to be in reasonable agreement with a value predicted for the reflected intensity at an imperfect crystal with finite absorption. (orig.).

  17. Microwave power engineering generation, transmission, rectification

    CERN Document Server

    Okress, Ernest C

    1968-01-01

    Microwave Power Engineering, Volume 1: Generation, Transmission, Rectification considers the components, systems, and applications and the prevailing limitations of the microwave power technology. This book contains four chapters and begins with an introduction to the basic concept and developments of microwave power technology. The second chapter deals with the development of the main classes of high-power microwave and optical frequency power generators, such as magnetrons, crossed-field amplifiers, klystrons, beam plasma amplifiers, crossed-field noise sources, triodes, lasers. The third

  18. Radiation effects on optical data transmission systems

    International Nuclear Information System (INIS)

    Leskovar, B.

    1989-01-01

    The state of the art of optical transmitters, low loss fiber waveguides and receivers in both steady state and pulsed radiation environments is reviewed and summarized. Emphasis is placed on the effects of irradiation on the performance of light emitting and laser diodes, optical fiber waveguides and photodiodes. The influence of radiation-induced attenuation of optical fibers due to total dose, dose rate, time after irradiation, temperature, radiation history, photobleaching, OH and impurity content, dopant type and concentration is described. The performance of candidate components of the transmission system intended for deployment in the Superconducting Super Collider Detector and primary beam tunnel nuclear environment is discussed

  19. Transmission Electron Microscope Measures Lattice Parameters

    Science.gov (United States)

    Pike, William T.

    1996-01-01

    Convergent-beam microdiffraction (CBM) in thermionic-emission transmission electron microscope (TEM) is technique for measuring lattice parameters of nanometer-sized specimens of crystalline materials. Lattice parameters determined by use of CBM accurate to within few parts in thousand. Technique developed especially for use in quantifying lattice parameters, and thus strains, in epitaxial mismatched-crystal-lattice multilayer structures in multiple-quantum-well and other advanced semiconductor electronic devices. Ability to determine strains in indivdual layers contributes to understanding of novel electronic behaviors of devices.

  20. Extraordinary acoustic transmission mediated by Helmholtz resonators

    Directory of Open Access Journals (Sweden)

    Vijay Koju

    2014-07-01

    Full Text Available We demonstrate perfect transmission of sound through a rigid barrier embedded with Helmholtz resonators. The resonators are confined within a waveguide and they are oriented such that one neck protrudes onto each side of the barrier. Perfect sound transmission occurs even though the open area of the necks is less than 3% of the barrier area. Maximum transmission occurs at the resonant frequency of the Helmholtz resonator. Because the dimensions of the Helmholtz resonators are much smaller than the resonant wavelength, the transmission is independent of the direction of sound on the barrier and of the relative placement of the necks. Further, we show that the transmitted sound experiences a continuous phase transition of π radians as a function of frequency through resonance. In simulations of adjacent resonators with slightly offset resonance frequencies, the phase difference leads to destructive interference. By expanding the simulation to a linear array of tuned Helmholtz resonators we show that it is possible to create an acoustic lens. The ability of Helmholtz resonator arrays to manipulate the phase of a plane acoustic wave enables a new class of sonic beam-forming devices analogous to diffractive optics.

  1. The transmission of differing energy beta particles through various materials

    International Nuclear Information System (INIS)

    Quayle, D.R.

    1996-04-01

    The transmission of beta particles is frequently calculated in the same fashion as that of gamma rays, where the mass attenuation coefficient is defined by the slope of the exponential function. Numerous authors have used this approximation including Evans (1955), Loevinger (1952), and Chabot et. al. (1988). Recent work by McCarthy et. al. (1995) indicated that the exponential function seemed to fit well over a particular region of the transmission curve. Upon further investigation, the author decided to verify McCarthy's results by the use of different absorber materials and attempt to reproduce the experiments. A theoretical method will be used to estimate the transmission of the beta particles through the three absorbers, aluminum, zirconium, and iron. An alternate Monte Carlo code, the Electron Gamma Shower version 4 code (EGS4) will also be used to verify that the experiment is approximating a pencil beam of beta particles. Although these two methods offer a good cross check for the experimental data, they pose a conflict in regards to the type of beam that is to be generated. The experimental lab setup uses a collimated beam of electrons that will impinge upon the absorber, while the codes are written using a pencil beam. A minor discrepancy is expected to be observed in the experimental results and is currently under investigation by McCarthy. The results of this project supported the theory that the beta mass attenuation coefficient was accurately represented by the slope of an exponential function, but only for that particular region of the transmission curve that has a minimal absorber thickness. By fitting the data beyond 50% of the beta particle range this theory does not hold true. The theory generated by McCarthy (1995) and the EGS4 Monte Carlo code indicated that the transmission curve for a pencil beam was not accurately represented by an exponential function. The results of this experiment appeared to provide additional support to this assumption

  2. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  3. Telecommunication using muon beams

    International Nuclear Information System (INIS)

    Arnold, R.C.

    1976-01-01

    Telecommunication is effected by generating a beam of mu mesons or muons, varying a property of the beam at a modulating rate to generate a modulated beam of muons, and detecting the information in the modulated beam at a remote location

  4. External proton and Li beams

    International Nuclear Information System (INIS)

    Schuff, Juan A.; Burlon, Alejandro A.; Debray, Mario E.; Kesque, Jose M.; Kreiner, Andres J.; Stoliar, Pablo A.; Naab, Fabian; Ozafran, Mabel J.; Vazquez, Monica E.; Perez de la Hoz, A.; Somacal, Hector; Valda, Alejandro; Canevas, S.; Ruffolo, M.; Tasat, D.R.; Muhlmann, M. C.

    2000-01-01

    In the frame of a feasibility study to introduce proton therapy in Argentina in a collaborative agreement between the Physics and Radiobiology Departments of the National Atomic Energy Commission or Argentina and the Centre de Protontherapie de Orsay, France, external proton and Li beams were produced at the TANDAR accelerator in Buenos Aires. The specific aim of this work was to start radiobiology studies on cell cultures and small laboratory animals. In particular we seek to determine here the relative biological effectiveness, RBE, for proton and Li beams as a function of energy for different tumor and normal cell lines. The 24 MeV proton beam was diffused using a 25 μm gold foil and extracted through a Kapton window to obtain a homogeneous field (constant to 95%) of about 7 cm in diameter. Measurements were carried out with quasi-monoenergetic beams (of 20.2 ± 0.07 MeV, 2.9 ± 0.10 MeV y 1.5 ± 0.1 MeV for protons and 21.4 ± 0.4 MeV for Lithium). Proton fluence and Bragg peaks were measured. The dose delivered in each case was monitored on-line with a calibrated transmission ionization chamber. Three cell lines PDV, PDVC 57 and V 79 (as a reference) were irradiated with γ-rays, proton and lithium beams with linear energy transfer (LET) from 2 to 100 keV/μm. RBE values in the range of 1.2-5.9 were obtained. In addition preliminary studies on chromosomal aberrations and viability of alveolar macrophages were carried out. (author)

  5. Cooling and squeezing the fluctuations of a nanomechanical beam by indirect quantum feedback control

    International Nuclear Information System (INIS)

    Zhang Jing; Liu Yuxi; Nori, Franco

    2009-01-01

    We study cooling and squeezing the fluctuations of a nanomechanical beam using quantum feedback control. In our model, the nanomechanical beam is coupled to a transmission line resonator via a superconducting quantum interference device. The leakage of the electromagnetic field from the transmission line resonator is measured using homodyne detection. This measured signal is then used to design a quantum feedback control signal to drive the electromagnetic field in the transmission line resonator. Although the control is imposed on the transmission line resonator, this quantum feedback control signal indirectly affects the thermal motion of the nanomechanical beam via the inductive beam-resonator coupling, making it possible to cool and squeeze the fluctuations of the beam, allowing it to approach the standard quantum limit.

  6. Electron-Beam Produced Air Plasma: Optical Measurement of Beam Current

    Science.gov (United States)

    Vidmar, Robert; Stalder, Kenneth; Seeley, Megan

    2006-10-01

    Experiments to quantify the electron beam current and distribution of beam current in air plasma are discussed. The air plasma is produced by a 100-keV 10-mA electron beam source that traverses a transmission window into a chamber with air as a target gas. Air pressure is between 1 mTorr and 760 Torr. Strong optical emissions due to electron impact ionization are observed for the N2 2^nd positive line at 337.1 nm and the N2^+ 1^st negative line at 391.4 nm. Calibration of optical emissions using signals from the isolated transmission window and a Faraday plate are discussed. The calibrated optical system is then used to quantify the electron distribution in the air plasma.

  7. Safe LHC beam commissioning

    International Nuclear Information System (INIS)

    Uythoven, J.; Schmidt, R.

    2007-01-01

    Due to the large amount of energy stored in magnets and beams, safety operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring System and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and energy. (author)

  8. LANSCE beam current limiter

    International Nuclear Information System (INIS)

    Gallegos, F.R.

    1996-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

  9. Nuclear stopping in transmission experiments

    International Nuclear Information System (INIS)

    Glazov, Lev G.; Sigmund, Peter

    2003-01-01

    Energy-loss spectra, mean and peak energy loss, and straggling due to elastic nuclear scattering have been studied theoretically as a function of target thickness and deflection angle of an initially monochromatic and well-collimated ion beam. The goal of this work has been to provide a generally valid scheme for nuclear-stopping corrections, allowing to determine electronic-stopping forces from energy-loss spectra measured in transmission geometry. Calculations have been based on the generalized Bothe-Landau theory of energy loss and multiple scattering. Our peak energy losses at zero emergence angle show close (∼10%) agreement with predictions of Fastrup et al. on the basis of the Bohr-Williams theory. However, predicted mean and peak energy losses are found to more sensitively depend on the underlying interatomic potential than unrestricted, i.e. angle-integrated mean or peak energy losses. Both elastic energy loss and multiple scattering are known to obey scaling laws involving only two combinations of the pertinent variables and atomic parameters. The dependence on deflection angle and foil thickness of mean and peak energy loss obeys a simple combination of these scaling laws. Comments are made on potential errors due to uncertainties in the nuclear-stopping correction applied in the literature with specific reference to central papers in low-velocity stopping

  10. Beta attenuation transmission system (BATS)

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm/sup 2/, of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A /sup 90/Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (..mu..P) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined.

  11. Beta attenuation transmission system (BATS)

    International Nuclear Information System (INIS)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm 2 , of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A 90 Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (μP) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined

  12. A low background pulsed neutron polyenergetic beam

    International Nuclear Information System (INIS)

    Adib, M.; Abdelkawy, A.; Habib, N.; abuelela, M.; Wahba, M.; kilany, M.; Kalebebin, S.M.

    1992-01-01

    A low background pulsed neutron polyenergetic thermal beam at ET-R R-1 is produced by a rotor and rotating collimator suspended in magnetic fields. Each of them is mounted on its mobile platform and whose centres are 66 cm apart, rotating synchronously at speeds up to 16000 rpm. It was found that the neutron burst produced by the rotor with almost 100% transmission passes through the collimator, when the rotation phase between them is 28.8 degree Moreover the background level achieved at the detector position is low, constant and free from peaks due to gamma rays and fast neutrons accompanying the reactor thermal beam.3 fig

  13. Power beaming providing a space power infrastructure

    International Nuclear Information System (INIS)

    Bamberger, J.A.; Coomes, E.P.

    1992-01-01

    This paper, based on two levels of technology maturity, applied the power beaming concept to four panned satellite constellations. The analysis shows that with currently available technology, power beaming can provide mass savings to constellations in orbits ranging from low-Earth orbit to geosynchronous orbit. Two constellations, space surveillance and tracking system and space-based radar, can be supported with current technology. The other two constellations, space-based laser array and boost surveillance and tracking system, will require power and transmission system improvements before their breakeven specific mass is achieved. A doubling of SP-100 conversion efficiency from 10 to 20% would meet or exceed breakeven for these constellations

  14. Beam current monitors in the NLCTA

    International Nuclear Information System (INIS)

    Nantista, C.; Adolphsen, C.

    1997-05-01

    The current profile along the 126 ns, multi-bunch beam pulse in the Next Linear Collider Test Accelerator (NLCTA) is monitored with fast toroids (rise time ∼ 1 ns). Inserted at several positions along the beam line, they allow one to track current transmission as a function of position along the bunch train. Various measurements, such as rise time, current, width, and slope, are made on the digitized signals, which can be corrected in software by means of stored frequency response files. The design and implementation of these devices is described

  15. The beam dump tunnels

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

  16. Ion beam diagnosis

    International Nuclear Information System (INIS)

    Strehl, P.

    1994-04-01

    This report is an introduction to ion beam diagnosis. After a short description of the most important ion beam parameters measurements of the beam current by means of Faraday cups, calorimetry, and beam current transformers and measurements of the beam profile by means of viewing screens, profile grids and scanning devices, and residual gas ionization monitors are described. Finally measurements in the transverse and longitudinal phase space are considered. (HSI)

  17. Optical Axis Identification Technique for Free Space Optics Transmission

    Directory of Open Access Journals (Sweden)

    Yuki Tashiro

    2017-07-01

    Full Text Available This paper describes optical axis adjustment technique for an active free space optics transmission system. This system precisely controls the direction of a collimated thin laser beam using a motor driven laser emitting mechanism and positioning photodiodes. Before beginning laser beam feedback control, it is required to guide the laser beam within the range of the positioning photodiodes for initial laser beam alignment. This paper proposes an arrival position presumption method of laser beam traveling along the long distance from transmitter. A positioning sensor containing several photodiodes measures laser luminescence distribution, and analytically calculates the optical axis of laser beam according to the modified Gaussian beam optics based on four or five distributed local intensity of laser luminescence. Experiments are conducted to evaluate the accuracy of the presumption, and results reveal that the method is effective in leading the laser beam onto a distant receiver.

  18. Transmission line capital costs

    International Nuclear Information System (INIS)

    Hughes, K.R.; Brown, D.R.

    1995-05-01

    The displacement or deferral of conventional AC transmission line installation is a key benefit associated with several technologies being developed with the support of the U.S. Department of Energy's Office of Energy Management (OEM). Previous benefits assessments conducted within OEM have been based on significantly different assumptions for the average cost per mile of AC transmission line. In response to this uncertainty, an investigation of transmission line capital cost data was initiated. The objective of this study was to develop a database for preparing preliminary estimates of transmission line costs. An extensive search of potential data sources identified databases maintained by the Bonneville Power Administration (BPA) and the Western Area Power Administration (WAPA) as superior sources of transmission line cost data. The BPA and WAPA data were adjusted to a common basis and combined together. The composite database covers voltage levels from 13.8 to 765 W, with cost estimates for a given voltage level varying depending on conductor size, tower material type, tower frame type, and number of circuits. Reported transmission line costs vary significantly, even for a given voltage level. This can usually be explained by variation in the design factors noted above and variation in environmental and land (right-of-way) costs, which are extremely site-specific. Cost estimates prepared from the composite database were compared to cost data collected by the Federal Energy Regulatory Commission (FERC) for investor-owned utilities from across the United States. The comparison was hampered because the only design specifications included with the FERC data were voltage level and line length. Working within this limitation, the FERC data were not found to differ significantly from the composite database. Therefore, the composite database was judged to be a reasonable proxy for estimating national average costs

  19. Transmission positron microscopes

    International Nuclear Information System (INIS)

    Doyama, Masao; Kogure, Yoshiaki; Inoue, Miyoshi; Kurihara, Toshikazu; Yoshiie, Toshimasa; Oshima, Ryuichiro; Matsuya, Miyuki

    2006-01-01

    Immediate and near-future plans for transmission positron microscopes being built at KEK, Tsukuba, Japan, are described. The characteristic feature of this project is remolding a commercial electron microscope to a positron microscope. A point source of electrons kept at a negative high voltage is changed to a point source of positrons kept at a high positive voltage. Positional resolution of transmission microscopes should be theoretically the same as electron microscopes. Positron microscopes utilizing trapping of positrons have always positional ambiguity due to the diffusion of positrons

  20. ETR transmission systems

    International Nuclear Information System (INIS)

    Metzler, D.

    1983-01-01

    The presentation concentrates on factors associated with transmission systems for reactors and/or reactor relevant devices. For present day mirrors and their upgrades where power levels are in the few hundred kW range, waveguide systems with mode control are preferred. Beyond the early 1990's time frame are the ETR DEMO and reactor devices. These require injected power levels of about 75 MW. If only power oscillators are available at that time, then a MARS like transmission system may be appropriate or possibly a guided wave waveguide

  1. Transmission grid security

    CERN Document Server

    Haarla, Liisa; Hirvonen, Ritva; Labeau, Pierre-Etienne

    2011-01-01

    In response to the growing importance of power system security and reliability, ""Transmission Grid Security"" proposes a systematic and probabilistic approach for transmission grid security analysis. The analysis presented uses probabilistic safety assessment (PSA) and takes into account the power system dynamics after severe faults. In the method shown in this book the power system states (stable, not stable, system breakdown, etc.) are connected with the substation reliability model. In this way it is possible to: estimate the system-wide consequences of grid faults; identify a chain of eve

  2. The neutron transmission of single crystal MgO filters

    International Nuclear Information System (INIS)

    Carpenter, J.M.; Hilleke, R.O.

    1989-01-01

    We have measured and analyzed the wavelength dependence of the transmission probability of a beam of neutrons passing through a single crystal MgO filter at 77 K. The 12.7 cm filter transmits 70% or more of the incident beam at wavelengths greater than about 1.8 A. At shorter wavelengths the transmission probability drops sharply, with 50% transmission occurring at about 1.2 A, and 1% transmission for the range 0.1-0.4 A. We have determined that cooling the filter to 77 K improves the transmission of >1 A neutrons, while further cooling to 25 K shows little additional improvement, and no improvement for short wavelengths. We have identified the wavelengths of the sharp dips in the transmission found in this region caused by Bragg scattering in MgO. We also show how these peaks may be used to calibrate the wavelength scale of time-of-flight measurements taken on instruments using similar filters. (orig.)

  3. On doing two things at once: dolphin brain and nose coordinate sonar clicks, buzzes and emotional squeals with social sounds during fish capture.

    Science.gov (United States)

    Ridgway, Sam; Samuelson Dibble, Dianna; Van Alstyne, Kaitlin; Price, DruAnn

    2015-12-01

    Dolphins fishing alone in open waters may whistle without interrupting their sonar clicks as they find and eat or reject fish. Our study is the first to match sound and video from the dolphin with sound and video from near the fish. During search and capture of fish, free-swimming dolphins carried cameras to record video and sound. A hydrophone in the far field near the fish also recorded sound. From these two perspectives, we studied the time course of dolphin sound production during fish capture. Our observations identify the instant of fish capture. There are three consistent acoustic phases: sonar clicks locate the fish; about 0.4 s before capture, the dolphin clicks become more rapid to form a second phase, the terminal buzz; at or just before capture, the buzz turns to an emotional squeal (the victory squeal), which may last 0.2 to 20 s after capture. The squeals are pulse bursts that vary in duration, peak frequency and amplitude. The victory squeal may be a reflection of emotion triggered by brain dopamine release. It may also affect prey to ease capture and/or it may be a way to communicate the presence of food to other dolphins. Dolphins also use whistles as communication or social sounds. Whistling during sonar clicking suggests that dolphins may be adept at doing two things at once. We know that dolphin brain hemispheres may sleep independently. Our results suggest that the two dolphin brain hemispheres may also act independently in communication. © 2015. Published by The Company of Biologists Ltd.

  4. Measurement of fish movements at depths to 6000 m using a deep-ocean lander incorporating a short base-line sonar utilizing miniature code-activated transponder technology

    Science.gov (United States)

    Bagley, P. M.; Bradley, S.; Priede, I. G.; Gray, P.

    1999-12-01

    Most research on animal behaviour in the deep ocean (to depths of 6000 m) is restricted to the capture of dead specimens or viewing activity over small areas of the sea floor by means of cameras or submersibles. This paper describes the use of a miniature acoustic code-activated transponder (CAT) tag and short base-line sonar to track the movements of deep-sea fish in two dimensions over an area 1 km in diameter centred on a lander platform. The CAT tags and sonar are transported to the deep-sea floor by means of a subsea mooring which is ballasted so that it lands and remains on the sea floor for the duration of the tracking experiment (the lander). A description of the CAT, lander and short base-line sonar is given. Results are presented to illustrate the operation of the system.

  5. Towards an optimal transmission system

    International Nuclear Information System (INIS)

    Calviou, M.

    2005-01-01

    This presentation provided background on National Grid USA and discussed transmission investment in the United States (US) and United Kingdom. It also discussed barriers to transmission investments and improvements, thoughts on solutions and a long-term vision. The presentation identified that transmission investment should follow from clear reliability rules designed to promote better operation and management; investment does not necessarily mean new rights-of-way; and transmission investment should target benefits to customers. It was stated that US transmission investment levels have decreased. A comparison between US and UK transmission investment was presented along with a chart of increasing US congestion costs. Barriers to investment in US transmission include vertical integration; misperception of transmission as a market product; federal and state jurisdiction issues; fragmentation in transmission ownership and operation; rate cap based plans that impact transmission; lack of clarity in cost allocation; and the site selection process. Possible solutions include policy and incentives, promoting independence and resolving structural issues. tabs., figs

  6. Beam diagnostics for low energy beams

    Directory of Open Access Journals (Sweden)

    J. Harasimowicz

    2012-12-01

    Full Text Available Low-energetic ion and antimatter beams are very attractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of particles per second and significant fraction of energy loss in matter at keV beam energies. A modular set of particle detectors has been developed to suit the particular beam diagnostic needs of the ultralow-energy storage ring (USR at the future facility for low-energy antiproton and ion research, accommodating very low beam intensities at energies down to 20 keV. The detectors include beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring. In this paper, the design of all detectors is presented in detail and results from beam measurements are shown. The resolution limits of all detectors are described and options for further improvement summarized. Whilst initially developed for the USR, the instrumentation described in this paper is also well suited for use in other low-intensity, low-energy accelerators, storage rings, and beam lines.

  7. Watching Handball Transmissions

    DEFF Research Database (Denmark)

    Frandsen, Kirsten

    2010-01-01

    and competent when mastering the game and in relation to others. The study shows that entertainment concerns both affective involvement and identity formation, as social and cultural meaning seem to be at the root of involvement. Even though both men and women find great joy in the transmissions, their viewing...

  8. Intergenerational Transmission of Volunteering

    NARCIS (Netherlands)

    Bekkers, René

    2007-01-01

    In this article, I investigate the strength of intergenerational transmission of volunteering for non-profit associations in The Netherlands. Data from the Family Survey of the Dutch Population 2000 reveal that there are significant relations between current volunteering and parental volunteering in

  9. Open access to transmission

    International Nuclear Information System (INIS)

    Keith, D.M.

    1996-01-01

    For the past 12 to 15 years, the US electric power and energy industry and its federal regulators have been going through a prolonged exercise leading to opening up the national interconnected transmission grid for all qualified wholesale users to have open and equal access. The debates have been painful in a sense that not all parties - especially some of the transmission system owning utilities - believe that the concept of Open Access is achievable, due to technical constraints on the systems. The present Open Access activity is limited to wholesales transaction under the federal jurisdiction, but several states are either experimenting with or considering retail wheeling. In fact, the FERC - Federal Energy Regulatory Commission - has already expanded its view to embrace retail transmission, if the retail transaction involves the use of the interstate transmission systems which are under FERC's jurisdiction. This paper delves into some of the results of the technical cost and pricing analysis for open access. The statutes and resulting regulations are not addressed herein. (author). 1 fig

  10. Intergenerational transmission of volunteerism

    NARCIS (Netherlands)

    Bekkers, R.H.F.P.

    2007-01-01

    In this article, I investigate the strength of intergenerational transmission of volunteering for non-profit associations in The Netherlands. Data from the Family Survey of the Dutch Population 2000 reveal that there are significant relations between current volunteering and parental volunteering in

  11. Measurement of centroid trajectory of Dragon-I electron beam

    International Nuclear Information System (INIS)

    Jiang Xiaoguo; Wang Yuan; Zhang Wenwei; Zhang Kaizhi; Li Jing; Li Chenggang; Yang Guojun

    2005-01-01

    The control of the electron beam in an intense current linear induction accelerator (LIA) is very important. The center position of the electron beam and the beam profile are two important parameters which should be measured accurately. The setup of a time-resolved measurement system and a data processing method for determining the beam center position are introduced for the purpose of obtaining Dragon-I electron beam trajectory including beam profile. The actual results show that the centroid position error can be controlled in one to two pixels. the time-resolved beam centroid trajectory of Dragon-I (18.5 MeV, 2 kA, 90 ns) is obtained recently in 10 ns interval, 3 ns exposure time with a multi-frame gated camera. The results show that the screw movement of the electron beam is mainly limited in an area with a radius of 0.5 mm and the time-resolved diameters of the beam are 8.4 mm, 8.8 mm, 8.5 mm, 9.3 mm and 7.6 mm. These results have provided a very important support to several research areas such as beam trajectory tuning and beam transmission. (authors)

  12. Neutron filters for producing monoenergetic neutron beams

    International Nuclear Information System (INIS)

    Harvey, J.A.; Hill, N.W.; Harvey, J.R.

    1982-01-01

    Neutron transmission measurements have been made on high-purity, highly-enriched samples of 58 Ni (99.9%), 60 Ni (99.7%), 64 Zn (97.9%) and 184 W (94.5%) to measure their neutron windows and to assess their potential usefulness for producing monoenergetic beams of intermediate energies from a reactor. Transmission measurements on the Los Alamos Sc filter (44.26 cm Sc and 1.0 cm Ti) have been made to determine the characteristics of the transmitted neutron beam and to measure the total cross section of Sc at the 2.0 keV minimum. When corrected for the Ti and impurities, a value of 0.35 +- 0.03 b was obtained for this minimum

  13. DIAGNOSTICS FOR ION BEAM DRIVEN HIGH ENERGY DENSITY PHYSICS EXPERIMENTS

    International Nuclear Information System (INIS)

    Bieniosek, F.M.; Henestroza, E.; Lidia, S.; Ni, P.A.

    2010-01-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30-mA K + beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (VISAR), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  14. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection.

    Science.gov (United States)

    Luo, Dong; Ibrahim, Zainah; Ma, Jianxun; Ismail, Zubaidah; Iseley, David Thomas

    2016-12-16

    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering.

  15. Increased nuclear safety and reliability through power beaming

    International Nuclear Information System (INIS)

    Coomes, E.P.; Widrig, R.D.

    1989-01-01

    Space satellites and platforms currently include self-contained power systems to supply the energy necessary to accomplish mission objectives. With power beaming, the power system is separate from the satellite and the two are connected by an energy beam. This approach is analogous to earth-based central station power generation and distribution over transmission lines to various customers. In space, power is produced by power satellites (central power generating stations) and transmitted via energy beams to individual users. Power beaming has the ability to provide an order of magnitude increase in power availability over solar-based power systems with less mass on orbit. The technologies needed for power beaming are being developed today under existing programs directed by the Strategic Defense Initiative Office, the National Aeronautics and Space Administration, and the US Department of Energy. A space power architecture based on power beaming would greatly increase the safety and reliability of employing nuclear power in space

  16. Studies of the beam-beam interaction for the LHC

    International Nuclear Information System (INIS)

    Krishnagopal, S.; Furman, M.A.; Turner, W.C.

    1999-01-01

    The authors have used the beam-beam simulation code CBI to study the beam-beam interaction for the LHC. We find that for nominal LHC parameters, and assuming only one bunch per beam, there are no collective (coherent) beam-beam instabilities. We have investigated the effect of sweeping one of the beams around the other (a procedure that could be used as a diagnostic for head-on beam-beam collisions). We find that this does not cause any problems at the nominal current, though at higher currents there can be beam blow-up and collective beam motion. consequence of quadrupole collective effects

  17. A new high-speed X-ray beam chopper

    International Nuclear Information System (INIS)

    McPherson, A.; Wang, J.; Lee, P. L.; Mills, D. M.

    1999-01-01

    A new high-speed x-ray beam chopper using laser scanner technology has been developed and tested on the SRI-CAT sector 1 beamline at the Advanced Photon Source (APS) storage ring (1). As illustrated in figure 1, it is compact in size and has two sets of transmission windows: BK-7 glass for visible light transmission and 0.23-mm-thick Be for the transmission of x-rays. The rotor is made of aluminum and has a diameter of 50.8 mm. A 0.5-mm-wide and 2.29-mm-tall slit is cut through the center of the rotor. The circumference of the rotor has a coating of 1-mm-thick Ni, which gives an attenuation of 10 8 at 30 keV. Turning at nearly 80000 RPM, this beam chopper has an opening time window of 2450 ns, corresponding to 67% of the revolution time of the APS storage ring. The primary feature in selecting laser scanner technology to develop into an x-ray beam chopper was the high level of rotational speed control of the rotor that makes up the beam chopper element (2). By using an optical feedback circuit to sample the rotational speed four times each revolution, the jitter in the position of the transmission open time window is only 3 ns at the 3 standard deviation level. The APS storage ring orbital frequency, supplied by the control room, is divided down to provide the appropriate drive frequency for the beam chopper motor controller. By this means, both the storage ring and the beam chopper are operating off the same master clock. After a turn-on time of about 15 to 20 seconds, the rotational precision of the motor results in immediate phase locking to the temporal structure of the APS storage ring. By inserting a Stanford delay generator between the frequency divider and the beam chopper motor controller, the phase between the storage ring temporal structure and the beam chopper rotation can be adjusted to position the transmission time window of the beam chopper on any desired part of the storage ring fill pattern. If an asymmetric fill pattern is used in the APS storage

  18. Research on atmospheric transmission distortion of Gauss laser using multiple phase screen method

    Science.gov (United States)

    Zhang, Yizhuo; Wang, Qiushi; Gu, Haidong

    2018-02-01

    The laser beam is attenuated, broadened, defocused and may even be deflected from its initial propagation direction as it propagates through the atmosphere. It leads to the decrease of the laser intensity of the receiving surface. Gauss beam is the fundamental components of all possible laser waveforms. Therefore, research on the transmission of the Gauss laser has far-reaching consequences in optical communication, weaponry, target designation, ranging, remote sensing and other applications that require transmission of laser beams through the atmosphere. In this paper, we propose a laboratory simulation method using multi-phase screen to calculate the effects of atmospheric turbulence. Theoretical analysis of Gauss laser transmission in the atmosphere is given. By calculating the propagation of the Gauss beam TEM00, the far field intensity and phase distribution is shown. By the given method, the optical setup is presented and used for optimizing the adaptive optics algorithm.

  19. Analyzing the Propagation Behavior of a Gaussian Laser Beam through Seawater and Comparing with Atmosphere

    Directory of Open Access Journals (Sweden)

    F Dabbagh Kashani

    2013-12-01

    Full Text Available Study of the beam propagation behavior through oceanic media is a challenging subject. In this paper, based on generalized Collins integral, the mean irradiance profile of Gaussian laser beam propagation through ocean is investigated. Power In Special Bucket (PIB is calculated. Using analytical expressions and calculating seawater transmission, the effects of absorption and scattering on beam propagation are studied. Based on these formulae, propagation in ocean and atmosphere are compared. The effects of some optical and environmental specifications, such as divergence angle and chlorophyll concentration in seawater on beam propagation by using mean irradiance, PIB and analytical formula of oceanic transmission are studied. The calculated results are shown graphically.

  20. Wireless OAM transmission system based on elliptical microstrip patch antenna.

    Science.gov (United States)

    Chen, Jia Jia; Lu, Qian Nan; Dong, Fei Fei; Yang, Jing Jing; Huang, Ming

    2016-05-30

    The multiplexing transmission has always been a focus of attention for communication technology. In this paper, the radiation characteristics of circular microstrip patch antenna was firstly analyzed based on cavity model theory, and then spiral beams carrying orbital angular momentum (OAM) were generated, using elliptical microstrip patch antenna, with a single feed probe instead of a standard circular patch with two feedpoints. Moreover, by combining the proposed elliptic microstrip patch antenna with Universal Software Radio Peripheral (USRP), a wireless OAM transmission system was established and the real-time transmission of text, image and video in a real channel environment was realized. Since the wireless OAM transmission has the advantage of good safety and high spectrum utilization efficiency, this work has theoretical significance and potential application.

  1. Microwave power - An energy transmission alternative for the year 2000

    Science.gov (United States)

    Nalos, E.; Sperber, R.

    1980-01-01

    Recent technological advances related to the feasibility of efficient RF-dc rectification make it likely that by the year 2000 the transmission of power through space will have become a practical reality. Proposals have been made to power helicopters, aircraft, balloons, and rockets remotely. Other proposals consider the transfer of power from point to point on earth via relay through space or a transmission of power from large power sources in space. Attention has also been given to possibilities regarding the transmission of power between various points in the solar system. An outline is provided of the microwave power transmission system envisaged for the solar power satellite, taking into account the transmitting antenna, the receiver on earth, aspects of beam formation and control, transmitter options, the receiving antenna design, and cost and efficiency considerations.

  2. V123 Beam Synchronous Encoder Module

    International Nuclear Information System (INIS)

    Kerner, T.; Conkling, C. R.; Oerter, B.

    1999-01-01

    The V123 Synchronous Encoder Module transmits events to distributed trigger modules and embedded decoders around the RHIC rings where they are used to provide beam instrumentation triggers [1,2,3]. The RHIC beam synchronous event link hardware is mainly comprised of three VMEbus board designs, the central input modules (V201), and encoder modules (V123), and the distributed trigger modules (V124). Two beam synchronous links, one for each ring, are distributed via fiberoptic and fanned out via twisted wire pair cables. The V123 synchronizes with the RF system clock derived from the beam bucket frequency and a revolution fiducial pulse. The RF system clock is used to create the beam synchronous event link carrier and events are synchronized with the rotation fiducial. A low jitter RF clock is later recovered from this carrier by phase lock loops in the trigger modules. Prioritized hardware and software triggers fill up to 15 beam event code transmission slots per revolution while tracking the ramping RF acceleration frequency and storage frequency. The revolution fiducial event is always the first event transmitted which is used to synchronize the firing of the abort kicker and to locate the first bucket for decoders distributed about the ring

  3. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  4. Electron beam instabilities in gyrotron beam tunnels

    International Nuclear Information System (INIS)

    Pedrozzi, M.; Alberti, S.; Hogge, J.P.; Tran, M.Q.; Tran, T.M.

    1997-10-01

    Electron beam instabilities occurring in a gyrotron electron beam can induce an energy spread which might significantly deteriorate the gyrotron efficiency. Three types of instabilities are considered to explain the important discrepancy found between the theoretical and experimental efficiency in the case of quasi-optical gyrotrons (QOG): the electron cyclotron maser instability, the Bernstein instability and the Langmuir instability. The low magnetic field gradient in drift tubes of QOG makes that the electron cyclotron maser instability can develop in the drift tube at very low electron beam currents. Experimental measurements show that with a proper choice of absorbing structures in the beam tunnel, this instability can be suppressed. At high beam currents, the electrostatic Bernstein instability can induce a significant energy spread at the entrance of the interaction region. The induced energy spread scales approximately linearly with the electron beam density and for QOG one observes that the beam density is significantly higher than the beam density of an equivalent cylindrical cavity gyrotron. (author) figs., tabs., refs

  5. The Transmission Line for the SPIDER experiment

    International Nuclear Information System (INIS)

    Boldrin, Marco; De Lorenzi, Antonio; Recchia, Mauro; Toigo, Vanni; Bonicelli, Tullio; Simon, Muriel

    2011-01-01

    The 100 keV Ion Source Test facility - Source for the Production of Ions of Deuterium Extracted from RF plasma (SPIDER) - is aimed to test the full scale prototype of the Ion Source for the ITER 1 MeV Neutral Beam Injector (NBI). The SPIDER facility requires the construction of a High Voltage Deck (HVD) and of a High Voltage Transmission Line (TL) respectively to host the Ion Source Power Supplies system polarized at 100 kV and to carry the power and signal conductors to the beam accelerator. In already existing NBI systems with beam energy above 100 keV, the TL is realized with the SF 6 Gas Insulated Line technology. In the SPIDER TL case, the presence of a large inner conductor (half meter diameter), would make the pressurized TL a complex and costly component; therefore a free air insulated solution has been proposed. The paper focuses on the design of this TL, which has to host inside the complex high potential (100 kV) inner electrode a number of power and measuring conductors and has to minimize the Electro Magnetic Interferences (EMI) produced by the frequent grids breakdowns. Finite Element (FE) analyses have been performed to verify the configuration from the electrostatic point of view, to evaluate EMI screening effectiveness and to assess the impact of the relatively high thermal dissipation of power conductors located inside the high potential electrode. Moreover, an experimental test campaign has been carried out on a TL mockup to validate the TL electrostatic configuration under DC voltage. Finally, the paper reports on the status of procurement activities for the Transmission Line.

  6. Successful Beam-Beam Tuneshift Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bishofberger, Kip Aaron [Univ. of California, Los Angeles, CA (United States)

    2005-01-01

    The performance of synchrotron colliders has been limited by the beam-beam limit, a maximum tuneshift that colliding bunches could sustain. Due to bunch-to-bunch tune variation and intra-bunch tune spread, larger tuneshifts produce severe emittance growth. Breaking through this constraint has been viewed as impossible for several decades. This dissertation introduces the physics of ultra-relativistic synchrotrons and low-energy electron beams, with emphasis placed on the limits of the Tevatron and the needs of a tuneshift-compensation device. A detailed analysis of the Tevatron Electron Lens (TEL) is given, comparing theoretical models to experimental data whenever possible. Finally, results of Tevatron operations with inclusion of the TEL are presented and analyzed. It is shown that the TEL provides a way to shatter the previously inescapable beam-beam limit.

  7. BEAMS3D Neutral Beam Injection Model

    Energy Technology Data Exchange (ETDEWEB)

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  8. Acoustical characteristic predictions of a multi-layer system of a submerged vehicle hull mounted sonar simplified to an infinite planar model

    Directory of Open Access Journals (Sweden)

    Sung-Hee Kim

    2012-06-01

    Full Text Available Hull Mounted Sonar (HMS is a long range submerged vehicle's hull-mounted passive sonar system which detects low-frequency noise caused by machineries of enemy ships or submerged vehicles. The HMS needs a sound absorption /insulation multi-layer structure to shut out the self-noise from own machineries and to amplify signals from outside. Therefore, acoustic analysis of the multi-layer system should be performed when the HMS is designed. This paper simplified the HMS multi-layer system to be an infinite planar multi-layer model. Also, main excitations that influence the HMS were classified into mechanical, plane wave and turbulent flow excitation, and the investigations for each excitation were performed for various models. Stiffened multi-layer analysis for mechanical excitation and general multi-layer analysis for turbulent flow excitation were developed. The infinite planar multi-layer analysis was expected to be more useful for preliminary design stage of HMS system than the infinite cylindrical model because of short analysis time and easiness of parameter study.

  9. Dynamics of a split torque helicopter transmission

    Science.gov (United States)

    Krantz, Timothy L.

    1994-06-01

    Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system dynamics and performance of a split torque gearbox that uses a balance beam mechanism for load sharing. The Lagrange method was applied to develop a system of equations of motion. The mathematical model includes time-varying gear mesh stiffness, friction, and manufacturing errors. Cornell's method for calculating the stiffness of spur gear teeth was extended and applied to helical gears. The phenomenon of sidebands spaced at shaft frequencies about gear mesh fundamental frequencies was simulated by modeling total composite gear errors as sinusoid functions. Although the gearbox has symmetric geometry, the loads and motions of the two power paths differ. Friction must be considered to properly evaluate the balance beam mechanism. For the design studied, the balance beam is not an effective device for load sharing unless the coefficient of friction is less than 0.003. The complete system stiffness as represented by the stiffness matrix used in this analysis must be considered to precisely determine the optimal tooth indexing position.

  10. Mechanisms, Transmissions and Applications

    CERN Document Server

    Corves, Burkhard

    2012-01-01

    The first Workshop on Mechanisms, Transmissions and Applications -- MeTrApp-2011 was organized by the Mechatronics Department at the Mechanical Engineering Faculty, “Politehnica” University of Timisoara, Romania, under the patronage of the IFToMM Technical Committees Linkages and Mechanical Controls and Micromachines. The workshop brought together researchers and students who work in disciplines associated with mechanisms science and offered a great opportunity for scientists from all over the world to present their achievements, exchange innovative ideas and create solid international links, setting the trend for future developments in this important and creative field. The topics treated in this volume are mechanisms and machine design, mechanical transmissions, mechatronic and biomechanic applications, computational and experimental methods, history of mechanism and machine science and teaching methods.

  11. Wireless transmission of power

    International Nuclear Information System (INIS)

    Grotz, T.

    1991-01-01

    This paper reports that it has been proven by researchers that electrical energy can be propagated around the world between the surface of the Earth and the ionosphere at extremely low frequencies in what is known as the Schumann Cavity. Experiments to data have shown that electromagnetic waves with frequencies in the range of 8 Hz, the fundamental Schumann Resonance frequency, propagate with litter attenuation around the planet within the Schumann Cavity. It is the intent of this research to determine if the Schumann Cavity can be resonated, if the power that is delivered to the cavity propagated with very low losses, and if power can be extracted at other locations within the cavity. Experimental data collected and calculations made in recent years support the hypothesis that wireless power transmission is a viable and practical alternative to the present systems of power transmission

  12. Regional transmission subsystem planning

    Energy Technology Data Exchange (ETDEWEB)

    Costa Bortoni, Edson da [Quadrante Softwares Especializados Ltda., Itajuba, MG (Brazil); Bajay, Sergio Valdir; Barros Correia, Paulo de [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica; Santos, Afonso Henriques Moreira; Haddad, Jamil [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    This work presents an approach for the planning of transmission systems by employing mixed--integer linear programming to obtain a cost and operating characteristics optimized system. The voltage loop equations are written in a modified form, so that, at the end of the analysis, the model behaves as a DC power flow, with the help of the two Kirchhoff`s laws, exempting the need of interaction with an external power flow program for analysis of the line loading. The model considers the occurrence of contingencies, so that the final result is a network robust to the most severe contingencies. This whole technique is adapted to the regional electric power transmission subsystems. (author) 9 refs., 4 figs.

  13. Beam Loss in Linacs

    CERN Document Server

    Plum, M.A.

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  14. Charged corpuscular beam detector

    Energy Technology Data Exchange (ETDEWEB)

    Hikawa, H; Nishikawa, Y

    1970-09-29

    The present invention relates to a charged particle beam detector which prevents transient phenomena disturbing the path and focusing of a charged particle beam travelling through a mounted axle. The present invention provides a charged particle beam detector capable of decreasing its reaction to the charge in energy of the charged particle beam even if the relative angle between the mounted axle and the scanner is unstable. The detector is characterized by mounting electrically conductive metal pieces of high melting point onto the face of a stepped, heat-resistant electric insulating material such that the pieces partially overlap each other and individually provide electric signals, whereby the detector is no longer affected by the beam. The thickness of the metal piece is selected so that an eddy current is not induced therein by an incident beam, thus the incident beam is not affected. The detector is capable of detecting a misaligned beam since the metal pieces partially overlap each other.

  15. Available transmission capacity assessment

    Directory of Open Access Journals (Sweden)

    Škokljev Ivan

    2012-01-01

    Full Text Available Effective power system operation requires the analysis of vast amounts of information. Power market activities expose power transmission networks to high-level power transactions that threaten normal, secure operation of the power system. When there are service requests for a specific sink/source pair in a transmission system, the transmission system operator (TSO must allocate the available transfer capacity (ATC. It is common that ATC has a single numerical value. Additionally, the ATC must be calculated for the base case configuration of the system, while generation dispatch and topology remain unchanged during the calculation. Posting ATC on the internet should benefit prospective users by aiding them in formulating their requests. However, a single numerical value of ATC offers little for prospect for analysis, planning, what-if combinations, etc. A symbolic approach to the power flow problem (DC power flow and ATC offers a numerical computation at the very end, whilst the calculation beforehand is performed by using symbols for the general topology of the electrical network. Qualitative analysis of the ATC using only qualitative values, such as increase, decrease or no change, offers some new insights into ATC evaluation, multiple transactions evaluation, value of counter-flows and their impact etc. Symbolic analysis in this paper is performed after the execution of the linear, symbolic DC power flow. As control variables, the mathematical model comprises linear security constraints, ATC, PTDFs and transactions. The aim is to perform an ATC sensitivity study on a five nodes/seven lines transmission network, used for zonal market activities tests. A relatively complicated environment with twenty possible bilateral transactions is observed.

  16. Dynamic Strategic Information Transmission

    OpenAIRE

    Mikhail Golosov; Vasiliki Skreta; Aleh Tsyvinski; Andrea Wilson

    2011-01-01

    This paper studies strategic information transmission in a dynamic environment where, each period, a privately informed expert sends a message and a decision maker takes an action. Our main result is that, in contrast to a static environment, full information revelation is possible. The gradual revelation of information and the eventual full revelation is supported by the dynamic rewards and punishments. The construction of a fully revealing equilibrium relies on two key features. The first f...

  17. Operational electricity transmission rates

    International Nuclear Information System (INIS)

    Roggen, M.

    1997-01-01

    In a liberalized electricity market both the consumers and the producers of electricity must pay for the use of the power transmission network. Thus, the net manager has unlimited options to realize efficiency improvements. A neutral and transparent management of the power grid is necessary to avoid disturbance of the market. KEMA Consulting translated abstract ideas and strategic advices to operational concepts in its report 'A framework for the determination of tariffs of the transport in the Dutch electricity sector'

  18. [Mumps vaccine virus transmission].

    Science.gov (United States)

    Otrashevskaia, E V; Kulak, M V; Otrashevskaia, A V; Karpov, I A; Fisenko, E G; Ignat'ev, G M

    2013-01-01

    In this work we report the mumps vaccine virus shedding based on the laboratory confirmed cases of the mumps virus (MuV) infection. The likely epidemiological sources of the transmitted mumps virus were children who were recently vaccinated with the mumps vaccine containing Leningrad-Zagreb or Leningrad-3 MuV. The etiology of the described cases of the horizontal transmission of both mumps vaccine viruses was confirmed by PCR with the sequential restriction analysis.

  19. Photon beam commissioning of an Elekta Synergy linear accelerator

    Science.gov (United States)

    Al Mashud, Md Abdullah; Tariquzzaman, M.; Jahangir Alam, M.; Zakaria, GA

    2017-12-01

    The aim of this study is to present the results of commissioning of Elekta Synergy linear accelerator (linac). The acceptance test and commissioning were performed for three photon beams energies 4 MV, 6 MV and 15 MV and for the multileaf collimator (MLC). The percent depth doses (PDDs), in-plane and cross-plane beam profiles, head scatter factors (Sc), relative photon output factors (Scp), universal wedge transmission factor and MLC transmission factors were measured. The size of gantry, collimator, and couch isocenter were also measured.

  20. Small passenger car transmission test; Chevrolet LUV transmission

    Science.gov (United States)

    Bujold, M. P.

    1980-01-01

    A 1978 Chevrolet LUV manual transmission tested per the applicable portions of a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the upper ninety percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Chevrolet LUV transmission.