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Sample records for surface peres coil

  1. Improved SNR of phased-array PERES coils via simulation study

    International Nuclear Information System (INIS)

    RodrIguez, Alfredo O; Medina, LucIa

    2005-01-01

    A computational comparison of signal-to-noise ratio (SNR) was performed between a conventional phased array of two circular-shaped coils and a petal resonator surface array. The quasi-static model and phased-array optimum SNR were combined to derive an SNR formula for each array. Analysis of mutual inductance between coil petals was carried out to compute the optimal coil separation and optimum number of petal coils. Mutual interaction between coil arrays was not included in the model because this does not drastically affect coil performance. Phased arrays of PERES coils show a 114% improvement in SNR over that of the simplest circular configuration. (note)

  2. An inflatable surface coil for rectal imaging

    International Nuclear Information System (INIS)

    Martin, J.F.; Hajek, P.C.; Baker, L.L.; Gylys-Morin, V.; Mattrey, R.F.

    1986-01-01

    Surface coils have become ubiquitous in MR imaging of the body because of substantial gains in signal-to-noise ratio. Unfortunately, there are some anatomic regions, such as the prostate, for which surface coils have insufficient depth sensitivity. The authors have developed an inflatable, distributed capacitance, passively decoupled surface coil which is collapsed for insertion and reinflated for imaging. Images of the prostate are dramatically improved due to proximity of the coil. Lesions in cadaver specimens were observed which were not seen with body coil imaging. Clinical trials are expected to begin in September

  3. Muru & Pere rahvusvahelisele tippkonkursile

    Index Scriptorium Estoniae

    1999-01-01

    Rahvusvaheline Intellektuaalomandi Organisatsioon (World Intellectual Property Organization) mis korraldab oma Genfis asuva peamaja laiendamiseks rahvusvahelise arhitektuurikonkursi, valis 6.-8. IX arhitektuuribüroo Muru & Pere OÜ 28 finalisti hulka. Konkursiprojekt peab valmima 31. jaanuariks 2000.

  4. [Surface coils for magnetic-resonance images].

    Science.gov (United States)

    Rodríguez-González, Alfredo Odón; Amador-Baheza, Ricardo; Rojas-Jasso, Rafael; Barrios-Alvarez, Fernando Alejandro

    2005-01-01

    Since the introduction of magnetic resonance imaging in Mexico, the development of this important medical imaging technology has been almost non-existing in our country. The very first surface coil prototypes for clinical applications in magnetic resonance imaging has been developed at the Center of Research in Medical Imaging and Instrumentation of the Universidad Autónoma Metropolitana Iztapalapa (Metropolitan Autonomous University, Campus Iztapalapa). Two surface coil prototypes were built: a) a circular-shaped coil and b) a square-shaped coil for multiple regions of the body, such as heart, brain, knee, hands, and ankles. These coils were tested on the 1.5T imager of the ABC Hospital-Tacubaya, located in Mexico City. Brain images of healthy volunteers were obtained in different orientations: sagittal, coronal, and axial. Since images showed a good-enough clinical quality for diagnosis, it is fair to say that these coil prototypes can be used in the clinical environment, and with small modifications, they can be made compatible with almost any commercial scanner. This type of development can offer new alternatives for further collaboration between the research centers and the radiology community, in the search of new applications and developments of this imaging technique.

  5. Optimal design for MRI surface coils

    International Nuclear Information System (INIS)

    Rivera, M.; Vaquero, J.J.; Santos, A.; Pozo, F. del; Ruiz-Cabello, J.

    1997-01-01

    To demonstrate the possibility of designing and constructing specific surface coils or antennae for MRI viewing of each particular tissue producing better results than those provided by a general purpose surface coil. The study was performed by the Bioengineering and Telemedicine Group of Madrid Polytechnical University and was carried out at the Pluridisciplinary Institute of the Universidad Complutense in Madrid, using a BMT-47/40 BIOSPEC resonance unit from Bruker. Surface coils were custom-designed and constructed for each region to be studied, and optimized to make the specimen excitation field as homogeneous as possible, in addition to reducing the brightness artifact. First, images were obtained of a round, water phantom measuring 50 mm in diameter, after which images of laboratory rats and rabbits were obtained. The images thus acquired were compared with the results obtained with the coil provided by the manufacturer of the equipment, and were found to be of better quality, allowing the viewing of deeper tissue for the specimen as well as reducing the brightness artifact. The construction of surface coils for viewing specific tissues or anatomical regions improves image quality. The next step in this ongoing project will be the application of these concepts to units designed for use in humans. (Author) 14 refs

  6. Superior MR images with electronically tuned and decoupled surface coils

    International Nuclear Information System (INIS)

    Ingwersen, H.; Freisen, L.; Friedrich, A.; Kess, H.; Krause, N.; Meissner, R.; Popp, W.

    1987-01-01

    In order to gain free positioning of surface coils in linearly polarized transmitting coils, it is absolutely necessary to electronically decouple both coils. For circularly polarized transmitting coils, decoupling is necessary in any case. In addition to the decoupling circuit automatic electronic tuning of the surface coils is used to gain the bast ratio of signal to noise. This combination of electronically decoupling and tuning of the surface coils yields intrinsic patient safety concerning local power deposition as well as free positioning and easy handling at the same time. Block diagrams, circuit schemes, and MR images obtained with several different surface coils are shown

  7. MRI of the orbit with surface coils

    International Nuclear Information System (INIS)

    Reuther, G.; Requardt, H.; Siemens A.G., Erlangen

    1986-01-01

    MRI of the orbit is strongly improved by the use of surface coils due to a higher signal-to-noise ratio. Oblique views without moving the patient present the optic nerve in full length on one slice. First experience with a small number of cases demonstrates normal anatomy and lesions in detail only at T 1 -weighted pulse sequences. Losses in contrast variation and detail accuracy are caused by movements of the eyeballs. Edge artifacts due to chemical shifting impair the image quality. So far there are no pinters towards tissue-specific signal intensity behaviour. Procedure and most favourable parameters at 1 tesla are given. (orig.) [de

  8. Magnetic resonance dacryocystography: comparison between conventional surface coils and microscopic coils

    International Nuclear Information System (INIS)

    Abreu Junior, Luiz de; Wolosker, Angela Maria Borri; Borri, Maria Lucia; Galvao Filho, Mario de Melo; Hartmann, Luiz Guilherme de Carvalho; D'Ippolito, Giuseppe; Castro, Claudio Campi de

    2008-01-01

    Objective: Magnetic resonance imaging has been utilized in the evaluation of the lacrimal apparatus with some advantages over conventional dacryocystography. The present study was aimed at acquiring high resolution images utilizing microscopic coils for evaluating typical structures of the lacrimal apparatus as compared with the findings observed with conventional surface coils. Materials and methods: Five asymptomatic volunteers with no history of epiphora were submitted to high-field magnetic resonance imaging with microscopic and conventional surface coils, and STIR sequence after instillation of saline solution. The definition of normal anatomic structures of lacrimal apparatuses was compared utilizing conventional and microscopic surface coils. Based on a consensual scoring system, the mean values for each structure were calculated by two observers. Results: In 90% of cases, higher scores were attributed to images acquired with the microscopic coil. On average, a 1.17 point increase was observed in the scoring of anatomic structures imaged with the microscopic coil. Additionally, a subjective improvement was observed in the signal-to-noise ratio with the microscopic coil. Conclusion: Magnetic resonance dacryocystography with microscopic coils is the appropriate method for evaluating the lacrimal apparatus, providing images with better quality as compared with those acquired with conventional surface coils. (author)

  9. Comparison of surface coil and knee coil for evaluation of the patellar cartilage by MR imaging

    International Nuclear Information System (INIS)

    Steen, M. van den; Maeseneer, M. de; Hoste, M.; Vanderdood, K.; Ridder, F. de; Osteaux, M.

    2003-01-01

    Purpose: The aim of this work was to compare the knee coil and the surface coil for the visualisation of the patellar cartilage. Materials and methods: In 28 patients (17 women, 11 men) with an average age of 40 years (range 14-76) with knee pain MR was performed. Transverse images were obtained using a fast spin echo proton density weighted sequence on a Philips Gyroscan Intera 1.5 T clinical system. Transverse images were obtained at the level of the patellar cartilage using both the surface and the knee coil. All images were evaluated by consensus of two radiologists. They evaluated a number of quality criteria on a 4-point scale. Criteria for artefacts were also graded on a 4-point scale. Results: For the visualisation of fluid there was no significant difference between the knee coil and the surface coil (P=0.021). For all other criteria regarding image quality and presence of imaging artefacts there was a significant difference between both coils (P<0.001) with the surface coil obtaining the better result. Conclusion: The use of the surface coil in the visualisation of the patellar cartilage can be recommended at knee MR

  10. Focused surface coil for MR imaging of the pituitary

    International Nuclear Information System (INIS)

    Harms, S.E.; Sherry, C.S.; Youshimura, L.; Lokken, R.; Hyde, J.S.

    1987-01-01

    A specially designed surface coil for pituitary MR imaging results in improved image quality over that achieved with conventional pituitary Mr imaging. The coil consists of connected planar pair coils with a variable intercoil distance to accommodate differences in head size. The sensitive field is focused deep to the surface between the two planar pairs. This arrangement optimizes the signal-to-noise ratio and allows better gradient magnification of the pituitary region. Fifteen subjects with a variety of pituitary disorders were imaged

  11. New method to design stellarator coils without the winding surface

    Science.gov (United States)

    Zhu, Caoxiang; Hudson, Stuart R.; Song, Yuntao; Wan, Yuanxi

    2018-01-01

    Finding an easy-to-build coils set has been a critical issue for stellarator design for decades. Conventional approaches assume a toroidal ‘winding’ surface, but a poorly chosen winding surface can unnecessarily constrain the coil optimization algorithm, This article presents a new method to design coils for stellarators. Each discrete coil is represented as an arbitrary, closed, one-dimensional curve embedded in three-dimensional space. A target function to be minimized that includes both physical requirements and engineering constraints is constructed. The derivatives of the target function with respect to the parameters describing the coil geometries and currents are calculated analytically. A numerical code, named flexible optimized coils using space curves (FOCUS), has been developed. Applications to a simple stellarator configuration, W7-X and LHD vacuum fields are presented.

  12. MRI surface-coil pair with strong inductive coupling.

    Science.gov (United States)

    Mett, Richard R; Sidabras, Jason W; Hyde, James S

    2016-12-01

    A novel inductively coupled coil pair was used to obtain magnetic resonance phantom images. Rationale for using such a structure is described in R. R. Mett et al. [Rev. Sci. Instrum. 87, 084703 (2016)]. The original rationale was to increase the Q-value of a small diameter surface coil in order to achieve dominant loading by the sample. A significant improvement in the vector reception field (VRF) is also seen. The coil assembly consists of a 3-turn 10 mm tall meta-metallic self-resonant spiral (SRS) of inner diameter 10.4 mm and outer diameter 15.1 mm and a single-loop equalization coil of 25 mm diameter and 2 mm tall. The low-frequency parallel mode was used in which the rf currents on each coil produce magnetic fields that add constructively. The SRS coil assembly was fabricated and data were collected using a tissue-equivalent 30% polyacrylamide phantom. The large inductive coupling of the coils produces phase-coherency of the rf currents and magnetic fields. Finite-element simulations indicate that the VRF of the coil pair is about 4.4 times larger than for a single-loop coil of 15 mm diameter. The mutual coupling between coils influences the current ratio between the coils, which in turn influences the VRF and the signal-to-noise ratio (SNR). Data on a tissue-equivalent phantom at 9.4 T show a total SNR increase of 8.8 over the 15 mm loop averaged over a 25 mm depth and diameter. The experimental results are shown to be consistent with the magnetic resonance theory of the emf induced by spins in a coil, the theory of inductively coupled resonant circuits, and the superposition principle. The methods are general for magnetic resonance and other types of signal detection and can be used over a wide range of operating frequencies.

  13. High-resolution MR imaging of triangular fibrocartilage complex (TFCC): comparison of microscopy coils and a conventional small surface coil

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Hiroshi [Department of Radiology, University of Tsukuba, Tsukuba (Japan); Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, 02115, Boston, MA (United States); Ueno, Teruko; Itai, Yuji [Department of Radiology, University of Tsukuba, Tsukuba (Japan); Tanaka, Toshikazu [Department of Orthopedic Surgery, Tsukuba Kinen Hospital, Tsukuba (Japan); Shindo, Masashi [Tsukuba University Hospital, Tsukuba (Japan)

    2003-10-01

    To compare MR images of the triangular fibrocartilage complex (TFCC) using microscopy coils with those using a conventional surface coil qualitatively and quantitatively. Proton density-weighted images and T2*-weighted images of the TFCC from ten normal volunteers were obtained with a conventional surface coil (C4 coil; 80 mm in diameter), a 47-mm microscopy surface coil and a 23-mm microscopy surface coil at 1.5 T. Qualitative image analysis of MR images with three coils was performed by two radiologists who assigned one of five numerical scores (0, nonvisualization; 1, poor; 2, average; 3, good; 4, excellent) for five TFCC components, which were disc proper, triangular ligament, meniscus homologue, ulnotriquetral and ulnolunate ligament. Quantitative analysis included the signal-to-noise ratio (S/N) of the disc proper of TFCC, the lunate cartilage, the lunate bone and the contrast-noise-ratio (C/N) between articular cartilage and disc proper or bone marrow were measured. All structures show higher scores qualitatively on MR with microscopy coils than those with a C4 coil, and the difference was significant with the exception of the ulnolunate ligament. MR with microscopy coils showed significantly higher S/N values than those with a conventional surface coil (P<0.05 to P<0.001). T2*-weighted images using microscopy coils showed significantly higher cartilage-disc proper C/N and cartilage-bone marrow C/N (P<0.01 to P<0.001). On proton density-weighted images, the C/N between cartilage and disc proper with two microscopy coils was significantly higher (P<0.01) than that with a conventional coil. High-resolution MR images of the normal wrist using microscopy coils were superior to those using a conventional surface coil qualitatively and quantitatively. High-resolution MR imaging with a microscopy coil would be a promising method to diagnose TFCC lesions. (orig.)

  14. Coil Tolerance Impact on Plasma Surface Quality for NCSX

    International Nuclear Information System (INIS)

    Brooks, Art; Reiersen, Wayne

    2003-01-01

    The successful operation of the National Compact Stellarator Experiment (NCSX) machine will require producing plasma configurations with good flux surfaces, with a minimum volume of the plasma lost to magnetic islands or stochastic regions. The project goal is to achieve good flux surfaces over 90% of the plasma volume. NCSX is a three period device designed to be operated with iota ranging from ∼0.4 on axis to ∼0.7 at the edge. The field errors of most concern are those that are resonant with 3/5 and 3/6 modes (for symmetry preserving field errors) and the 1/2 and 2/3 modes (for symmetry breaking field errors). In addition to losses inherent in the physics configuration itself, there will be losses from field errors arising from coil construction and assembly errors. Some of these losses can be recovered through the use of trim coils or correction coils. The impact of coil tolerances on plasma surface quality is evaluated herein for the NCSX design. The methods used in this evaluation are discussed. The ability of the NCSX trim coils to correct for field errors is also examined. The results are used to set coils tolerances for the various coil systems

  15. Eesti meister peresõbralikkuses : Eesti Post / Sulev Oll

    Index Scriptorium Estoniae

    Oll, Sulev, 1964-

    2001-01-01

    Äripäeva ning ajakirja Pere ja Kodu konkursil pälvis Eesti kõige peresõbralikuma firma tiitli Eesti Post. Tabel: 30 peresõbralikumat firmat. Tabel: Eesti Post toetuste jagamisel keskmisest heldem

  16. The experimental study on positioning of the surface coil for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Kyoji; Yotsui, Yoritaka; Koseki, Yonoshin [Osaka Dental Univ., Hirakata (Japan)

    2002-12-01

    We examined the correlation between signal intensity and setting angulations for magnetic resonance imagesobtained using a surface coil, which had a three inch surface coil, and dual coil, which and a three inch surface coil and an anterior neck coil. We took T2-3D weighted, T2-2D weighted and T1-2D weighted images with the angulated three-inch surface coil at 0-90 degrees with the magnetic direction. In every sequence, the maximum intensity with the dual coil was taken with angulations of 50-60 degrees. The intensity of the dual coil could be as much as the three times that of the single coil. As the angulations increased with the dual coil, the thickness of the effective intensity was decreased until it reached 50% of the maximum thickness. With the single coil it decreased until it reached 10%. When using a high-resolution coil that cannot be setup parallel with the magnetic direction, we recommend using a dual coil rather than a single coil to increase the signal intensity. In the oral cavity, the intraoral coil should be used with the extraoral coil as the phased array coil. This is the optimum condition of coil angulation for taking high resolution images. (author)

  17. Design of a quadrature surface coil for hyperpolarized 13C MRS cardiac metabolism studies in pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Frijia, F.; Hartwig, V.

    2013-01-01

    , the performance of the quadrature coil was compared with the single TX/RX circular and TX/RX butterfly coil, in order to verify the advantage of the proposed configuration over the single coils throughout the volume of interest for cardiac imaging in pig. Finally, the quadrature surface coil was tested...

  18. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    International Nuclear Information System (INIS)

    Solis, S E; Rodriguez, A O; Wang, R; Tomasi, D

    2011-01-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  19. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    Energy Technology Data Exchange (ETDEWEB)

    Solis, S E; Rodriguez, A O [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Wang, R; Tomasi, D, E-mail: arog@xanum.uam.mx [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-06-21

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  20. A multi-slot surface coil for MRI of dual-rat imaging at 4T

    Energy Technology Data Exchange (ETDEWEB)

    Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

    2011-07-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  1. Localized 31PNMR spectroscopy with ISIS and surface coils

    International Nuclear Information System (INIS)

    Heindel, W.; Schreier, G.; Steinbrich, W.; Glathe, S.; Huttmann, P.

    1990-01-01

    A new method for image-guided localized phosphorus NMR spectroscopy of superficial tissues has been investigated using a 1.5 Tesla whole-body-MR-system. We used a surface coil combined with adiabatic excitation pulses and a modified ISIS sequence. This approach is related to imaging sequences and thus permits a flexible and accurate determination of the volume of interest from 'conventional' proton images. The scope and advantages of the method are demonstrated by phantom studies. Clinical applications to the liver, renal transplants, and the mediastinum are described. (orig.) [de

  2. Inductance and resistance measurement method for vessel detection and coil powering in all-surface inductive heating systems composed of outer squircle coils

    Science.gov (United States)

    Kilic, Veli Tayfun; Unal, Emre; Demir, Hilmi Volkan

    2017-05-01

    In this work, we investigate a method proposed for vessel detection and coil powering in an all-surface inductive heating system composed of outer squircle coils. Besides conventional circular coils, coils with different shapes such as outer squircle coils are used for and enable efficient all-surface inductive heating. Validity of the method, which relies on measuring inductance and resistance values of a loaded coil at different frequencies, is experimentally demonstrated for a coil with shape different from conventional circular coil. Simple setup was constructed with a small coil to model an all-surface inductive heating system. Inductance and resistance maps were generated by measuring coil's inductance and resistance values at different frequencies loaded by a plate made of different materials and located at various positions. Results show that in an induction hob for various coil geometries it is possible to detect a vessel's presence, to identify its material type and to specify its position on the hob surface by considering inductance and resistance of the coil measured on at least two different frequencies. The studied method is important in terms of enabling safe, efficient and user flexible heating in an all-surface inductive heating system by automatically detecting the vessel's presence and powering on only the coils that are loaded by the vessel with predetermined current levels.

  3. Design of a surface-scanning coil detector for direct bacteria detection on food surfaces using a magnetoelastic biosensor

    Science.gov (United States)

    Chai, Yating; Wikle, Howard C.; Wang, Zhenyu; Horikawa, Shin; Best, Steve; Cheng, Zhongyang; Dyer, Dave F.; Chin, Bryan A.

    2013-09-01

    The real-time, in-situ bacteria detection on food surfaces was achieved by using a magnetoelastic biosensor combined with a surface-scanning coil detector. This paper focuses on the coil design for signal optimization. The coil was used to excite the sensor's vibration and detect its resonant frequency signal. The vibrating sensor creates a magnetic flux change around the coil, which then produces a mutual inductance. In order to enhance the signal amplitude, a theory of the sensor's mutual inductance with the measurement coil is proposed. Both theoretical calculations and experimental data showed that the working length of the coil has a significant effect on the signal amplitude. For a 1 mm-long sensor, a coil with a working length of 1.3 mm showed the best signal amplitude. The real-time detection of Salmonella bacteria on a fresh food surface was demonstrated using this new technology.

  4. Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

    International Nuclear Information System (INIS)

    Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

    2008-01-01

    Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging

  5. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

    Science.gov (United States)

    Weinberger, Oliver; Winter, Lukas; Dieringer, Matthias A; Els, Antje; Oezerdem, Celal; Rieger, Jan; Kuehne, Andre; Cassara, Antonino M; Pfeiffer, Harald; Wetterling, Friedrich; Niendorf, Thoralf

    2016-01-01

    The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation. Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each transmission regime flip angle distributions and blood-myocardium contrast are examined in a volunteer study of 12 subjects. The feasibility of the local transceiver RF coil array for cardiac chamber quantification at 3 Tesla is demonstrated. Our simulations and experiments demonstrate that cardiac MR at 3 Tesla using four-channel surface RF coil transmission is competitive versus current clinical CMR practice of large volume body RF coil transmission. The efficiency advantage of the 4TX/4RX setup facilitates shorter repetition times governed by local SAR limits versus body RF coil transmission at whole-body SAR limit. No statistically significant difference was found for cardiac chamber quantification derived with body RF coil versus four-channel surface RF coil transmission. Our simulation also show that the body RF coil exceeds local SAR limits by a factor of ~2 when driven at maximum applicable input power to reach the whole-body SAR limit. Pursuing local surface RF coil arrays for transmission in cardiac MR is a conceptually appealing alternative to body RF coil transmission, especially for patients with implants.

  6. Quadrature Slotted Surface Coil Pair for Magnetic Resonance Imaging at 4 Tesla: Phantom Study

    Directory of Open Access Journals (Sweden)

    Solis S.E.

    2012-01-01

    Full Text Available A coil array was composed of two slotted surface coils forming a structure with two plates at 900, each one having 6 circular slots and is introduced in this paper. Numerical simulations of the magnetic field of this coil array were performed at 170 MHz using the finite element method to study its behaviour. This coil array was developed for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode and quadrature driven. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. In vitro images showed the feasibility of this coil array for standard pulses and high field magnetic resonance imaging.

  7. Characterization and flip angle calibration of 13C surface coils for hyperpolarization studies

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Gutte, Henrik; Larsen, Majbrit M E

    The aim of the present work is to address the challenge of optimal The aim of the present work is to address the challenge of optimal flflip angle calibration of ip angle calibration of C surface coils in C surface coils in hyperpolarization studies. To this end, we characterize the spatial pro h...

  8. Four-channel surface coil array for sequential CW-EPR image acquisition

    Science.gov (United States)

    Enomoto, Ayano; Emoto, Miho; Fujii, Hirotada; Hirata, Hiroshi

    2013-09-01

    This article describes a four-channel surface coil array to increase the area of visualization for continuous-wave electron paramagnetic resonance (CW-EPR) imaging. A 776-MHz surface coil array was constructed with four independent surface coil resonators and three kinds of switches. Control circuits for switching the resonators were also built to sequentially perform EPR image acquisition for each resonator. The resonance frequencies of the resonators were shifted using PIN diode switches to decouple the inductively coupled coils. To investigate the area of visualization with the surface coil array, three-dimensional EPR imaging was performed using a glass cell phantom filled with a solution of nitroxyl radicals. The area of visualization obtained with the surface coil array was increased approximately 3.5-fold in comparison to that with a single surface coil resonator. Furthermore, to demonstrate the applicability of this surface coil array to animal imaging, three-dimensional EPR imaging was performed in a living mouse with an exogenously injected nitroxyl radical imaging agent.

  9. Analyses and Comparison of Bulk and Coil Surface Samples from the DWPF Slurry Mix Evaporator

    International Nuclear Information System (INIS)

    Hay, M.; Nash, C.; Stone, M.

    2012-01-01

    Sludge samples from the DWPF Slurry Mix Evaporator (SME) heating coil frame and coil surface were characterized to identify differences that might help identify heat transfer fouling materials. The SME steam coils have seen increased fouling leading to lower boil-up rates. Samples of the sludge were taken from the coil frame somewhat distant from the coil (bulk tank material) and from the coil surface (coil surface sample). The results of the analysis indicate the composition of the two SME samples are very similar with the exception that the coil surface sample shows ∼5-10X higher mercury concentration than the bulk tank sample. Elemental analyses and x-ray diffraction results did not indicate notable differences between the two samples. The ICP-MS and Cs-137 data indicate no significant differences in the radionuclide composition of the two SME samples. Semi-volatile organic analysis revealed numerous organic molecules, these likely result from antifoaming additives. The compositions of the two SME samples also match well with the analyzed composition of the SME batch with the exception of significantly higher silicon, lithium, and boron content in the batch sample indicating the coil samples are deficient in frit relative to the SME batch composition.

  10. MRI of prostate zonal anatomy with an endorectal surface coil

    International Nuclear Information System (INIS)

    Cornud, F.; Belin, X.; Melki, P.; Helenon, O.; Cretien, Y.; Dufour, B.; Moreau, J.F.

    1995-01-01

    The development of an endorectal surface coil now permits a partial study of the anatomical model developed by McNeal. Axial and coronal views, which were used to establish the model can be obtained in a short period of time with fast spin echo sequences. Axial views are performed along the proximal urethra and coronal views are performed along the axis of the distal urethra and the ejaculatory duts. Anatomical boundaries of the transitional zone are well delineated on axial views, illustrating the concept of 'inner gland'. The prostatic capsule and the neuro-vascular bundles, pathways of extension of the cancer out of the prostate are also well delineated. Coronal sections allow a very good anatomical study of the caudal junction of the vas deferens and the seminal vesicles (the so called weak space), pathway of tumor extension to the seminal vesicles. Differences in signal of the prostatic zones make the outer gland cancers very conspicuous as well as some transitional cancers which can show, in some cases, an homogeneous hyposignal. (authors). 15 refs., 14 figs

  11. Rectangle Surface Coil Array in a Grid Arrangement for Resonance Imaging

    Science.gov (United States)

    2016-02-13

    magnet wires with insulating coating for rectangular surface coils. The wires are formed into four one turn 145mm x 32mm rectangular coils...switchable array, RF magnetic field, NQR, MRI, NMR, tuning, decoupling I. INTRODUCTION ESONANCE imaging can be accomplished using Nuclear Magnetic ...grid array. This achieves the switchable array configuration. Later, investigations will have circuit controlled multiplexer for switching to

  12. Peresõbralik firma 2002 - Paikuse Saeveski / Kalev Petti

    Index Scriptorium Estoniae

    Petti, Kalev

    2002-01-01

    Ajakiri Pere ja Kodu ja ajaleht Äripäev selgitasid välja Eesti kõige peresõbralikuma ettevõtte. - Lisaks tabelid: Eesti töötajasõbralike ettevõtete TOP 50 ; Peresõbralike firmade TOP 50 ; Töökeskkonnasõbralike firmade TOP 50 ; Töötaja arengu sõbralike firmade TOP 50

  13. Clinical usefulness of a newly-developed head and neck surface coil for MR imaging

    International Nuclear Information System (INIS)

    Shimada, Morio; Kogure, Takashi; Hayashi, Sanshin

    1995-01-01

    To obtain correct diagnosis at early stages of cervical lymph node swelling, especially cases with suspected epipharyngeal carcinoma, and cerebral arterial sclerotic diseases, high-quality MR images visualizing the entire head and neck structures and vessels are of crucial importance. When obtaining images of head and neck regions using a head coil, signal intensity (SI) and signal to noise ratio (SNR) of regions below the hypopharynx are weakened. Moreover, when obtaining images of head and neck regions using an anterior neck coil, SI and SNR of upper regions of epipharynx are also weakened. In an attempt to solve these problems, we developed a new head and neck surface coil for MR imaging. With this new coil we were able to obtain better images (153 cases) from regions below the hypopharynx to the upper regions of the epipharynx in the same time as images obtained using the head coil and anterior neck coil. 2D TOF MR angiographic images (11 cases) obtained by the head and neck surface coil are superior to 2D TOF angiographic images obtained by the anterior neck coil. MR images obtained with this improved method are valuable in the evaluation and management of head and neck region disease. (author)

  14. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

    Directory of Open Access Journals (Sweden)

    Oliver Weinberger

    Full Text Available The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation.Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each transmission regime flip angle distributions and blood-myocardium contrast are examined in a volunteer study of 12 subjects. The feasibility of the local transceiver RF coil array for cardiac chamber quantification at 3 Tesla is demonstrated.Our simulations and experiments demonstrate that cardiac MR at 3 Tesla using four-channel surface RF coil transmission is competitive versus current clinical CMR practice of large volume body RF coil transmission. The efficiency advantage of the 4TX/4RX setup facilitates shorter repetition times governed by local SAR limits versus body RF coil transmission at whole-body SAR limit. No statistically significant difference was found for cardiac chamber quantification derived with body RF coil versus four-channel surface RF coil transmission. Our simulation also show that the body RF coil exceeds local SAR limits by a factor of ~2 when driven at maximum applicable input power to reach the whole-body SAR limit.Pursuing local surface RF coil arrays for transmission in cardiac MR is a conceptually appealing alternative to body RF coil transmission, especially for patients with implants.

  15. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

    Science.gov (United States)

    Winter, Lukas; Dieringer, Matthias A.; Els, Antje; Oezerdem, Celal; Rieger, Jan; Kuehne, Andre; Cassara, Antonino M.; Pfeiffer, Harald; Wetterling, Friedrich; Niendorf, Thoralf

    2016-01-01

    Introduction The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation. Methods Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each transmission regime flip angle distributions and blood-myocardium contrast are examined in a volunteer study of 12 subjects. The feasibility of the local transceiver RF coil array for cardiac chamber quantification at 3 Tesla is demonstrated. Results Our simulations and experiments demonstrate that cardiac MR at 3 Tesla using four-channel surface RF coil transmission is competitive versus current clinical CMR practice of large volume body RF coil transmission. The efficiency advantage of the 4TX/4RX setup facilitates shorter repetition times governed by local SAR limits versus body RF coil transmission at whole-body SAR limit. No statistically significant difference was found for cardiac chamber quantification derived with body RF coil versus four-channel surface RF coil transmission. Our simulation also show that the body RF coil exceeds local SAR limits by a factor of ~2 when driven at maximum applicable input power to reach the whole-body SAR limit. Conclusion Pursuing local surface RF coil arrays for transmission in cardiac MR is a conceptually appealing alternative to body RF coil transmission, especially for patients with implants. PMID:27598923

  16. Thermal performance of a spirally coiled finned tube heat exchanger under wet-surface conditions

    International Nuclear Information System (INIS)

    Wongwises, Somchai; Naphon, Paisarn

    2006-01-01

    This paper is a continuation of the author's previous work on spiral coil heat exchangers. In the present study, the heat transfer characteristics and the performance of a spirally coiled finned tube heat exchanger under wet-surface conditions are theoretically and experimentally investigated. The test section is a spiral-coil heat exchanger which consists of a steel shell and a spirally coiled tube unit. The spiral-coil unit consists of six layers of concentric spirally coiled finned tubes. Each tube is fabricated by bending a 9.6 mm diameter straight copper tube into a spiral-coil of four turns. The innermost and outermost diameters of each spiral-coil are 145.0 and 350.4 mm, respectively. Aluminium crimped spiral fins with thickness of 0.6 mm and outer diameter of 28.4 mm are placed around the tube. The edge of fin at the inner diameter is corrugated. Air and water are used as working fluids in shell side and tube side, respectively. The experiments are done under dehumidifying conditions. A mathematical model based on the conservation of mass and energy is developed to simulate the flow and heat transfer characteristics of working fluids flowing through the heat exchanger. The results obtained from the present model show reasonable agreement with the experimental data

  17. Comparative study between body and surface coils in magnetic resonance mammography of silicone prosthesis

    International Nuclear Information System (INIS)

    Scaranelo, Anabel Medeiros

    2001-01-01

    Magnetic resonance imaging scans using predefined parameters were performed in patients with silicone breast implants. The same group of patients was submitted to magnetic resonance imaging scans using surface breast coils and body coils, and the results were compared. A total of 43 single-lumen silicone-gel breast implants in 24 patients were examined. The signal-to-noise ratio was greater for the breast coil than for the body coil. Radial folds were identified with equal resolution by both in almost 82% of the cases on the right side and 95% on the left side. In about 5% of the cases the folds were seen exclusively when the breast coil used. The linguine sign was almost equally with both methods. In just one case the linguine sign was observed only by using the breast coil. Identification of building or irregularity of contours were concordant using both techniques. We concluded that although magnetic resonance imaging quality is better using a dedicated coil, silicone breast implants can be assessed with the same diagnostic accuracy using a body coil. (author)

  18. Surface coil imaging of the spine using fast sequences: Improvement of intensity profile and contrast behavior

    International Nuclear Information System (INIS)

    Requardt, H.; Deimling, M.; Weber, H.

    1986-01-01

    Sagittal and axial images obtained using a surface coil suffer from the extreme intensity profile caused by physical properties of the coil and the anatomic entity of subcutaneous fat. The authors present a measuring device that reduces these disadvantages by means of Helmholtz-type coils, and sequences that reduce the fat signal by dephasing its signal part. The extremely short repetition time (<30 msec) allows acquisition times shorter than 10 sec. Breath-holding for this short period to avoid movement artifacts is possible. Images are presented that illustrate the enhanced contrast of spinal tissue and surrounding structures. Comparisons are made with spin-echo and CHESS images

  19. The interaction of pulsed eddy current with metal surface crack for various coils

    International Nuclear Information System (INIS)

    Yang, H.-C.; Tai, C.-C.

    2002-01-01

    We study the interaction of pulsed eddy current (PEC) with metal surface cracks using various coils that have different geometric sizes. In the previous work, we have showed that the PEC technique can be used to inspect electrical-discharge-machined (EDM) notches with depth from 0.5 mm to 9 mm. The results showed that the relationship between PEC signals and crack depth is obvious. In this work, we further try a series of coils with different radii, heights, turns and shapes. We will discuss the effects of these coil parameters on the PEC signal. Some other critical problems of PEC measurements such as signal drift that caused by heating effect of coil currents will be studied. We also show more experiments on fatigue cracks to demonstrate the capability of PEC technique for cracks inspection

  20. Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness

    Science.gov (United States)

    Andrzejczyk, Rafał; Muszyński, Tomasz

    2016-12-01

    The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow inside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

  1. Do carotid MR surface coils affect PET quantification in PET/MR imaging?

    International Nuclear Information System (INIS)

    Willemink, Martin J; Eldib, Mootaz; Leiner, Tim; Fayad, Zahi A; Mani, Venkatesh

    2015-01-01

    To evaluate the effect of surface coils for carotid MR imaging on PET quantification in a clinical simultaneous whole-body PET/MR scanner. A cylindrical phantom was filled with a homogeneous 2L water-FDG mixture at a starting dose of 301.2MBq. Clinical PET/MR and PET/CT systems were used to acquire PET-data without a coil (reference standard) and with two carotid MRI coils (Siemens Special Purpose 8-Channel and Machnet 4-Channel Phased Array). PET-signal attenuation was evaluated with Osirix using 51 (PET/MR) and 37 (PET/CT) circular ROIs. Mean and maximum standardized uptake values (SUVs) were quantified for each ROI. Furthermore, SUVs of PET/MR and PET/CT were compared. For validation, a patient was scanned with an injected dose of 407.7MBq on both a PET/CT and a PET/MR system without a coil and with both coils. PET/MR underestimations were -2.2% (Siemens) and -7.8% (Machnet) for SUVmean, and -1.2% (Siemens) and -3.3% (Machnet) for SUVmax, respectively. For PET/CT, underestimations were -1.3% (Siemens) and -1.4% (Machnet) for SUVmean and -0.5% (both Siemens and Machnet) for SUVmax, respectively using no coil data as reference. Except for PET/CT SUVmax values all differences were significant. SUVs differed significantly between PET/MR and PET/CT with SUVmean values of 0.51-0.55 for PET/MR and 0.68-0.69 for PET/CT, respectively. The patient examination showed that median SUVmean values measured in the carotid arteries decreased from 0.97 without a coil to 0.96 (Siemens) and 0.88 (Machnet). Carotid surface coils do affect attenuation correction in both PET/MR and PET/CT imaging. Furthermore, SUVs differed significantly between PET/MR and PET/CT.

  2. High spatial resolution quantitative MR images: an experimental study of dedicated surface coils

    International Nuclear Information System (INIS)

    Gensanne, D; Josse, G; Lagarde, J M; Vincensini, D

    2006-01-01

    Measuring spin-spin relaxation times (T 2 ) by quantitative MR imaging represents a potentially efficient tool to evaluate the physicochemical properties of various media. However, noise in MR images is responsible for uncertainties in the determination of T 2 relaxation times, which limits the accuracy of parametric tissue analysis. The required signal-to-noise ratio (SNR) depends on the T 2 relaxation behaviour specific to each tissue. Thus, we have previously shown that keeping the uncertainty in T 2 measurements within a limit of 10% implies that SNR values be greater than 100 and 300 for mono- and biexponential T 2 relaxation behaviours, respectively. Noise reduction can be obtained either by increasing the voxel size (i.e., at the expense of spatial resolution) or by using high sensitivity dedicated surface coils (which allows us to increase SNR without deteriorating spatial resolution in an excessive manner). However, surface coil sensitivity is heterogeneous, i.e., it- and hence SNR-decreases with increasing depth, and the more so as the coil radius is smaller. The use of surface coils is therefore limited to the analysis of superficial structure such as the hypodermic tissue analysed here. The aim of this work was to determine the maximum limits of spatial resolution and depth compatible with reliable in vivo T 2 quantitative MR images using dedicated surface coils available on various clinical MR scanners. The average thickness of adipose tissue is around 15 mm, and the results obtained have shown that obtaining reliable biexponential relaxation analysis requires a minimum achievable voxel size of 13 mm 3 for a conventional volume birdcage coil and only of 1.7 mm 3 for the smallest available surface coil (23 mm in diameter). Further improvement in spatial resolution allowing us to detect low details in MR images without deteriorating parametric T 2 images can be obtained by image filtering. By using the non-linear selective blurring filter described in a

  3. Pere Albert: Barcelona Canon, Royal Advocate, Feudal Theorist

    Directory of Open Access Journals (Sweden)

    Kagay, Donald K.

    2002-06-01

    Full Text Available In this article, the life and career of one of Catalonia's greatest medieval legists is discussed. Using notarial and court documentation, the author explores the work of Pere Albert as judge and advocate. The Customs of Catalonia and other of Pere Albert's treatises form the basis for the review of the legist's career as a theorist in feudal law. The basis for this article is the collection of documents pertaining to Pere Albert, which the author includes in an appendix.

    En este artículo se estudia la vida y la carrera de uno de los jurisconsultos medievales más importantes de Cataluña. Utilizando la documentación notarial y judicial, el autor analiza la labor de Pere Albert como juez y abogado. ElsCostums de Catalunya y otros tratados de Pere Albert constituyen la base para el estudio de la carrera del jurisconsulto, como teórico en ley feudal y real. El artículo se basa en una colección de documentos originales relativos a Pere Albert, que el autor incluye en un apéndice.

  4. Preliminary results of endorectal surface coil magnetic resonance imaging for local staging of prostate cancer

    NARCIS (Netherlands)

    Jager, G. J.; Barentsz, J. O.; de la Rosette, J. J.; Rosenbusch, G.

    1994-01-01

    To evaluate the effectiveness of endorectal surface coil (ERC) magnetic resonance imaging (MRI) in the local staging of adenocarcinoma of the prostate (ACP). A total of 23 patients who were considered candidates for radical prostatectomy because of clinically localized ACP were examined by ERC-MRI.

  5. Whole-body MRI using a sliding table and repositioning surface coil approach

    International Nuclear Information System (INIS)

    Takahara, Taro; Kwee, Thomas; Luijten, Peter; Kibune, Satoshi; Ochiai, Reiji; Sakamoto, Tetsuro; Niwa, Tetsu; Van Cauteren, Marc

    2010-01-01

    To introduce and assess a new way of performing whole-body magnetic resonance imaging (MRI) using a non-integrated surface coil approach as available on most clinical MRI systems worldwide. Ten consecutive asymptomatic subjects prospectively underwent whole-body MRI for health screening. Whole-body MRI included T1-, T2- and diffusion-weighted sequences, and was performed using a non-integrated surface coil to image four different stations without patient repositioning. The four separately acquired stations were merged, creating seamless coronal whole-body T1-, T2- and diffusion-weighted images. Anatomical alignment, image quality at the boundaries of adjacent stations, and overall image quality of all stations were qualitatively assessed. The average time (±SD) taken to change the surface coil from one station to the next station was 53.8 (±7.1) s. The average total extra examination time ± SD was 2 min 41.4 s (±15.3 s). Anatomical alignment, image quality at the boundaries of adjacent stations, and overall image quality of all stations of T1-, T2- and diffusion-weighted whole-body MRI were overall graded as ''good'' to ''excellent''. This study shows that a time-efficient and high-quality whole-body MRI examination can easily be performed by using a non-integrated sliding surface coil approach. (orig.)

  6. Multi circular-cavity surface coil for magnetic resonance imaging of monkey's brain at 4 Tesla

    Science.gov (United States)

    Osorio, A. I.; Solis-Najera, S. E.; Vázquez, F.; Wang, R. L.; Tomasi, D.; Rodriguez, A. O.

    2014-11-01

    Animal models in medical research has been used to study humans diseases for several decades. The use of different imaging techniques together with different animal models offers a great advantage due to the possibility to study some human pathologies without the necessity of chirurgical intervention. The employ of magnetic resonance imaging for the acquisition of anatomical and functional images is an excellent tool because its noninvasive nature. Dedicated coils to perform magnetic resonance imaging experiments are obligatory due to the improvement on the signal-to-noise ratio and reduced specific absorption ratio. A specifically designed surface coil for magnetic resonance imaging of monkey's brain is proposed based on the multi circular-slot coil. Numerical simulations of the magnetic and electric fields were also performed using the Finite Integration Method to solve Maxwell's equations for this particular coil design and, to study the behavior of various vector magnetic field configurations and specific absorption ratio. Monkey's brain images were then acquired with a research-dedicated magnetic resonance imaging system at 4T, to evaluate the anatomical images with conventional imaging sequences. This coil showed good quality images of a monkey's brain and full compatibility with standard pulse sequences implemented in research-dedicated imager.

  7. RF pulse methods for use with surface coils: Frequency-modulated pulses and parallel transmission

    Science.gov (United States)

    Garwood, Michael; Uğurbil, Kamil

    2018-06-01

    The first use of a surface coil to obtain a 31P NMR spectrum from an intact rat by Ackerman and colleagues initiated a revolution in magnetic resonance imaging (MRI) and spectroscopy (MRS). Today, we take it for granted that one can detect signals in regions external to an RF coil; at the time, however, this concept was most unusual. In the approximately four decade long period since its introduction, this simple idea gave birth to an increasing number of innovations that has led to transformative changes in the way we collect data in an in vivo magnetic resonance experiment, particularly with MRI of humans. These innovations include spatial localization and/or encoding based on the non-uniform B1 field generated by the surface coil, leading to new spectroscopic localization methods, image acceleration, and unique RF pulses that deal with B1 inhomogeneities and even reduce power deposition. Without the surface coil, many of the major technological advances that define the extraordinary success of MRI in clinical diagnosis and in biomedical research, as exemplified by projects like the Human Connectome Project, would not have been possible.

  8. Study on Induction Heating Coil for Uniform Mold Cavity Surface Heating

    OpenAIRE

    Yu-Ting Sung; Sheng-Jye Hwang; Huei-Huang Lee; Durn-Yuan Huang

    2014-01-01

    Recently, energy saving is one of the important issues for polymer processing industry. Electromagnetic induction heating has many advantages such as fast heating and low energy consumption. Previous studies using electromagnetic induction heating for rapid tool heating have indicated that the temperature uniformity on a cavity surface is not easy to be achieved. In this paper, two different coils were used for heating uniform 7 mm thick hot work tool steel (JIS SKD61) surface. One is a four-...

  9. Neli Peret Hispaanias, tekstiilikunstnikest rääkimata / Katrin Pere

    Index Scriptorium Estoniae

    Pere, Katrin, 1952-

    1998-01-01

    9. - 12. märtsini Barcelonas ja Madridis toimunud European Textile Networki aastakonverentsist. Eestist osalesid : Lylian Meister, Lea Pruuli, Aet Ollisaar-Kalamees, Katrin Pere, Merike Männi, Aune Taamal, Anne Tootma, Signe Kivi, Peeter Pere

  10. Investigating the road surface effect to the fatigue life of an automotive coil spring

    Science.gov (United States)

    Putra, T. E.; Husaini

    2018-05-01

    This work aims to estimate the life of a coil spring considering road surface profiles. Strain signals were measured by installing a strain gage at the highest stress location of the coil spring and then driving the vehicle on country and village roads. The village road gave high amplitudes containing spikes when the tire touched a curb, bump or pothole. These conditions contributed to a higher loading rate to the car component, contributing to shorter useful fatigue life, which was only 140 reversals of blocks. Driving on the village road resulted in a 6-times decrease in the useful fatigue life of the component in comparison to the country road. In conclusion, the village road caused stronger vibrations to the component because it has a rough surface; meanwhile, the country road provided lower vibrations because the road was smooth.

  11. Performance of coils wound from long lengths of surface-coated, reacted, BSCCO-2212 conductor

    Energy Technology Data Exchange (ETDEWEB)

    Walker, M.S.; Hazelton, D.W.; Gardner, M.T. [Intermagnetics General Corp., Latham, NY (United States)] [and others

    1996-10-01

    React-before-wind surface-coated BSCCO-2212 is being established as a relatively low cost HTS conductor for practical applications. Quality tape is presently being manufactured in 450-500m lengths at a cost estimated to be 1/3-1/5 of the industry costs of BSCCO-2223 powder-in-tube tape. Robust, mechanically sound coils for applications ranging from NMR insert magnets to transformer windings are being made from this BSCCO-2212 tape. The coils have performed consistently through test and thermal cycling without degradation and as projected from short sample measurements. A hybrid approach, which uses mainly BSCCO- 2212 augmented by BSCCO-2223 conductor in the high radial field end regions, is expected to halve magnet system costs.

  12. Practical aspects of 13C surface receive coils with active decoupling and tuning circuit

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Mohr, Johan Jacob; Zhurbenko, Vitaliy

    2012-01-01

    is based on application-specified coil profile and includes impedance matching and balancing circuits. Active decoupling is implemented in order to minimize the influence of the receiving coil on the homogeneity of the transmit-coil field. Measurement results for a coil prototype are presented, including...

  13. Normal appearance of the prostate and seminal tract: MR imaging using an endorectal surface coil

    International Nuclear Information System (INIS)

    Kim, Myeong Jin; Lee, Jong Tae; Lee, Moo Sang; Choi, Pil Sik; Hong, Sung Joon; Lee, Yeon Hee; Choi, Hak Yong

    1994-01-01

    To assess the ability of MR imaging with an endorectal surface coil for the depiction of normal anatomical structure of prostate and its adjacent organs. MR imaging using an endorectal surface coil was performed in 23 male patients(age ; 20-75) to evaluate various prostatic and vasovesicular disorders, i. e, 14 cases of ejaculatory problems, 3 cases of hypogonadism, and 4 cases of prostatic cancers and 2 cases of benign prostatic hyperplasia. MR images were obtained with axial, sagittal and coronal fast spin echo long TR/TE images and axial spin echo short TR/TE images. Field of views was 10-12 cm and scan thickness was 3-5 mm. Depiction of normal anatomcial structures was excellent in all cases. On T2WI, zonal anatomy of the prostate and prostatic urethra, urethral crest, and ejaculatory duct were cleary visualized. On T1WI, periprostatic fat plane is more cleary visualized. On transverse images, periprostatic structures were well visualized on T1WI,and on T2WI, anterior fibromuscular stroma, transition zone and peripheral zone could be readily differentiated. Coronal images were more helpful in visualization of both central and peripheral zones. Vas deferens, ejaculatory duct and vermontanum were also more easily defined on these images. Sagittal images was helpful in the depiction of anterior fibromuscular stroma, central zone and peripheral zone with prostatic urethra and ejaculatory duct in a single plane. High resolution MR imaging with an endorectal surface coil can readily visualize the normal anatomy of the prostate and its related structures and may be useful in the evaluation of various diseases of prostate and vasvesicular system

  14. Normal appearance of the prostate and seminal tract: MR imaging using an endorectal surface coil

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myeong Jin; Lee, Jong Tae; Lee, Moo Sang; Choi, Pil Sik; Hong, Sung Joon; Lee, Yeon Hee; Choi, Hak Yong [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1994-06-15

    To assess the ability of MR imaging with an endorectal surface coil for the depiction of normal anatomical structure of prostate and its adjacent organs. MR imaging using an endorectal surface coil was performed in 23 male patients(age ; 20-75) to evaluate various prostatic and vasovesicular disorders, i. e, 14 cases of ejaculatory problems, 3 cases of hypogonadism, and 4 cases of prostatic cancers and 2 cases of benign prostatic hyperplasia. MR images were obtained with axial, sagittal and coronal fast spin echo long TR/TE images and axial spin echo short TR/TE images. Field of views was 10-12 cm and scan thickness was 3-5 mm. Depiction of normal anatomcial structures was excellent in all cases. On T2WI, zonal anatomy of the prostate and prostatic urethra, urethral crest, and ejaculatory duct were cleary visualized. On T1WI, periprostatic fat plane is more cleary visualized. On transverse images, periprostatic structures were well visualized on T1WI,and on T2WI, anterior fibromuscular stroma, transition zone and peripheral zone could be readily differentiated. Coronal images were more helpful in visualization of both central and peripheral zones. Vas deferens, ejaculatory duct and vermontanum were also more easily defined on these images. Sagittal images was helpful in the depiction of anterior fibromuscular stroma, central zone and peripheral zone with prostatic urethra and ejaculatory duct in a single plane. High resolution MR imaging with an endorectal surface coil can readily visualize the normal anatomy of the prostate and its related structures and may be useful in the evaluation of various diseases of prostate and vasvesicular system.

  15. A new holder and surface MRI coil for the examination of the newborn infant hip

    Energy Technology Data Exchange (ETDEWEB)

    Krasny, R. (Dept. of Diagnostic Radiology, Univ. of Technology, Aachen (Germany)); Casser, H.R. (Dept. of Orthopedics, Univ. of Technology, Aachen (Germany)); Requardt, H. (Siemens AG, Erlangen (Germany)); Botschek, A. (Dept. of Diagnostic Radiology, Univ. of Technology, Aachen (Germany))

    1993-11-01

    A special holder was developed for examination of the infant hip joint using MRI. This holder allows the infant hip joint to be examined both in a neutral position and in various defined functional positions. A special integrated surface coil, also developed for this purpose, provides the high spatial resolution required for assessment of the fine joint structures. Thirty infants were examined and the new device has proved useful in advanced hip dysplasia, therapy-resistant subluxation and luxation, and for operative therapy planning (reconstruction of the acetabular roof, redirectional osteotomies). Interpretation errors due to misprojection can be eliminated to a large extent since the holder allows standardized and reproducible positioning. (orig.)

  16. Results of MRI of the temporo-mandibular joint using optimised surface coils

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.; Kellermann, O.; Randzio, J.; Kniha, H.; Requardt, H.; Tiling, R.; Lissner, J.

    1988-11-01

    One hundred temporo-mandibular joints were examined with a super-conducting nuclear resonance tomograph (1.0 Tesla) using various high resolution surface coils. The optimal method proved to be a spin echo sequence with a repetition time of 1,000 msec and an echo period of 28 msec with a 4 mm slice width. There were significant advantages from the non-invasive MRT diagnosis of the temporo-mandibular joints when compared with CT and with arthrography in recognising abnormal discs, changes in the tissues and for post-operative control.

  17. High-resolution MR imaging of urethra for incontinence by means of intracavitary surface coils

    International Nuclear Information System (INIS)

    Yang, A.; Mostwin, J.L.; Genadry, R.; Yang, S.S.

    1991-01-01

    Urinary incontinence is a major medical problem affecting millions of older women. This paper demonstrates the use of dynamic MR imaging in noninvasive quantification of prolapse in all three pelvic compartments. In this exhibit we use high-resolution MR imaging with intracavity (intravaginal, intrarectal) and surface/intracavitary coils to diagnose intrinsic urethral pathology that prevents opening (dysuria) or coaptation (incontinence). Normal anatomy, congenital anatomy (pelvic floor defects, hypoplasia), acquired anatomy (periurethral cyst/divertivulum, tumor, hypertrophy), and operative failure as causes of incontinence (postoperative scarring, misplacement/dehiscence of sutures and flaps) are shown. We demonstrate a novel method for MR cine voiding cystourethrography. Technical factors and applications are discussed

  18. A combined solenoid-surface RF coil for high-resolution whole-brain rat imaging on a 3.0 Tesla clinical MR scanner.

    Science.gov (United States)

    Underhill, Hunter R; Yuan, Chun; Hayes, Cecil E

    2010-09-01

    Rat brain models effectively simulate a multitude of human neurological disorders. Improvements in coil design have facilitated the wider utilization of rat brain models by enabling the utilization of clinical MR scanners for image acquisition. In this study, a novel coil design, subsequently referred to as the rat brain coil, is described that exploits and combines the strengths of both solenoids and surface coils into a simple, multichannel, receive-only coil dedicated to whole-brain rat imaging on a 3.0 T clinical MR scanner. Compared with a multiturn solenoid mouse body coil, a 3-cm surface coil, a modified Helmholtz coil, and a phased-array surface coil, the rat brain coil improved signal-to-noise ratio by approximately 72, 61, 78, and 242%, respectively. Effects of the rat brain coil on amplitudes of static field and radiofrequency field uniformity were similar to each of the other coils. In vivo, whole-brain images of an adult male rat were acquired with a T(2)-weighted spin-echo sequence using an isotropic acquisition resolution of 0.25 x 0.25 x 0.25 mm(3) in 60.6 min. Multiplanar images of the in vivo rat brain with identification of anatomic structures are presented. Improvement in signal-to-noise ratio afforded by the rat brain coil may broaden experiments that utilize clinical MR scanners for in vivo image acquisition. 2010 Wiley-Liss, Inc.

  19. Mass and heat transfer at the outer surface of helical coils under single and two phase flow

    International Nuclear Information System (INIS)

    Abdel-Aziz, M.H.; Nirdosh, I.; Sedahmed, G.H.

    2016-01-01

    Highlights: • The work aims to develop reactors which need rapid temperature control. • Mass and heat transfer at the outer surface of helical coils was studied experimentally. • The experiments were conducted under gas sparing, single and two phase flow. • Variables were helical tube diameter, physical properties, and gas and liquid velocity. • Results verification in terms of natural convection and surface renewal mechanism was explained. - Abstract: The mass transfer behavior of the outer surface of vertical helical coil was studied by the electrochemical technique under single phase flow, gas sparging and two phase flow. Variables studied were helical tube diameter, physical properties of the solution, solution velocity and superficial gas velocity. The mass transfer data were correlated by dimensionless equations. Mass transfer enhancement ratio in case of two phase flow ranged from 1.1 to 4.9 compared to single phase flow. Implication of the results for the design and operation of helical coil reactors used to conduct L–S exothermic diffusion controlled reactions which need rapid temperature control were outlined. In this case the inner coil surface will act as a cooler while the outer surface will act a reaction surface. Immobilized enzyme catalyzed biochemical reactions where heat sensitive materials may be involved represent an example for the reactions which can employ the helical coil reactor. Also the importance of the results in the design of and operation of diffusion controlled membrane processes which employ helical coil membrane was noted. In view of the analogy between heat and mass transfer the possibility of using the results in the design and operation of helical coil heat exchangers was highlighted.

  20. Flexible, wireless, inductively coupled surface coil resonator for EPR tooth dosimetry

    International Nuclear Information System (INIS)

    Schreiber, Wilson; Petryakov, Sergey V.; Kmiec, Maciej M.; Feldman, Matthew A.; Wood, Victoria A.; Boyle, Holly K.; Flood, Ann Barry; Williams, Benjamin B.; Swartz, Harold M.; Meaney, Paul M.

    2016-01-01

    Managing radiation injuries following a catastrophic event where large numbers of people may have been exposed to life-threatening doses of ionizing radiation relies on the availability of biodosimetry to assess whether individuals need to be triaged for care. Electron Paramagnetic Resonance (EPR) tooth dosimetry is a viable method to accurately estimate the amount of ionizing radiation to which an individual has been exposed. In the intended measurement conditions and scenario, it is essential that the measurement process be fast, straightforward and provides meaningful and accurate dose estimations for individuals in the expected measurement conditions. The sensing component of a conventional L-band EPR spectrometer used for tooth dosimetry typically consists of a surface coil resonator that is rigidly, physically attached to the coupler. This design can result in cumbersome operation, limitations in teeth geometries that may be measured and hinder the overall utility of the dosimeter. A novel surface coil resonator has been developed for the currently existing L-band (1.15 GHz) EPR tooth dosimeter for the intended use as a point of care device by minimally trained operators. This resonator development provides further utility to the dosimeter, and increases the usability of the dosimeter by non-expert operators in the intended use scenario. (authors)

  1. Stochastization of Magnetic Field Surfaces in Tokamaks by an Inner Coil

    International Nuclear Information System (INIS)

    Chavez-Alarcon, Esteban; Herrera-Velazquez, J. Julio E.; Braun-Gitler, Eliezer

    2006-01-01

    A 3-D code has been developed in order to simulate the magnetic field lines in circular cross-section tokamaks. The toroidal magnetic field can be obtained from the individual fields of circular coils arranged around the torus, or alternatively, as a ripple-less field. The poloidal field is provided by a given toroidal current density profile. Proposing initial conditions for a magnetic filed line, it is integrated along the toroidal angle coordinate, and Poincare maps can be obtained at any desired cross section plane. Following this procedure, the code allows the mapping of magnetic field surfaces for the axisymmetric case. For this work, the density current profile is chosen to be bell-shaped, so that realistic safety factor profiles can be obtained. This code is used in order to study the braking up of external surfaces when the symmetry is broken by an inner coil with tilted circular loops, with the purpose of modelling the behaviour of ergodic divertors, such as those devised for TEXTOR

  2. Magnetic resonance imaging of cervical carcinoma using an endorectal surface coil

    International Nuclear Information System (INIS)

    Brocker, Kerstin A.; Alt, Céline D.; Gebauer, Gerhard; Sohn, Christof; Hallscheidt, Peter

    2014-01-01

    Introduction: The objective of this trial is to investigate the diagnostic value of magnetic resonance imaging (MRI) with an endorectal surface coil for precise local staging of patients with histologically proven cervical cancer by comparing the radiological, clinical, and histological results. Materials and methods: Women with cervical cancer were recruited for this trial between February 2007, and September 2010. All the patients were clinically staged according to the FIGO classification and underwent radiological staging by MRI that employed an endorectal surface coil. The staging results after surgery were compared to histopathology in all the operable patients. Results: A total of 74 consecutive patients were included in the trial. Forty-four (59.5%) patients underwent primary surgery, whereas 30 (40.5%) patients were inoperable according to FIGO and underwent primary radiochemotherapy. The mean age of the patients was 50.6 years. In 11 out of the 44 patients concordant staging results were obtained by all three staging modalities. Thirty-two of the 44 patients were concordantly staged by FIGO and histopathological examination, while only 16 were concordantly staged by eMRI and histopathological examination. eMRI overstaged tumors in 14 cases and understaged them in 7 cases. Conclusions: eMRI is applicable in patients with cervical cancer, yet of no benefit than staging with FIGO or standard pelvic MRI. The most precise preoperative staging procedure still appears to be the clinical examination

  3. 16-Channel surface coil for 13C-hyperpolarized spectroscopic imaging of cardiac metabolism in pig heart

    DEFF Research Database (Denmark)

    Frijia, Francesca; Santarelli, Maria Filomena; Koellisch, Ulrich

    2016-01-01

    Magnetic resonance spectroscopy (MRS) of hyperpolarized 13C pyruvate and its metabolites in large animal models is a powerful tool for assessing cardiac metabolism in patho-physiological conditions. In 13C studies, a high signal-to-noise ratio (SNR) is crucial to overcome the intrinsic data quality...... both targets. In this study, a 16-channel receive surface coil was designed for 13C hyperpolarized studies of the pig heart with a clinical 3-T scanner. The coil performance was characterized by phantom experiments and compared with that of a birdcage coil used in transmit/receive mode. Segmental...... of the 16-channel coil is recommended for studies of septal and anterior LV walls....

  4. PCB concentrations in Pere Marquette River and Muskegon River watersheds, 2002

    Science.gov (United States)

    Fogarty, Lisa R.

    2005-01-01

    Polychlorinated biphenyl compounds (PCBs) are a class of209 individual compounds (known as congeners) for which there are no known natural sources. PCBs are carcinogenic and bioaccumulative compounds. For over 40 years, PCBs were manufactured in the United States. The flame resistant property of PCBs made them ideal chemicals for use as flame-retardants, and as coolants and lubricants in transformers and other electrical equipment. PCBs were also used in heating coils, carbonless paper, degreasers, varnishes, lacquers, waterproofing material, and cereal boxes. In addition, they were frequently used in the manufacturing of plastics, adhesives, and paints.During the manufacturing period of PCBs, these chemicals entered the environment though atmospheric release during manufacturing and burning of PCB products, leaks and spills, and improper disposal. Although PCB manufacturing was banned over 20 years ago, PCBs still enter the environment from hazardous waste sites, improper disposals of PCB-containing products, weathering of asphalt and other substances containing PCBs, burning of PCB containing products, leakage from old equipment, leaching from landfills, and release from contaminated sediments. PCBs do not readily break down in the environment, thus remain there for long periods of time. A small amount may remain dissolved in water but most adhere to organic particles and bottom sediments.In sufficient concentrations, PCBs affect human, wildlife, and aquatic health. PCBs accumulate in fatty tissues of animals and fish and are passed on to those that eat them. PCBs are animal teratogens and potentially carcinogenic. They can cause death of animals, fish, and birds; death or low growth rate of plants; shortened lifespan; reproductive problems; and lower fertility. Women who are exposed to high levels of PCBs may have babies with slightly lower birth weights and transfer the PCBs through the breast milk, which may affect the immune system and motor development of

  5. 31P nuclear magnetic resonance surface coil study of ischemic preconditioned isolated perfused rat heart

    International Nuclear Information System (INIS)

    Yan Yongbin; Luo Xuechun; Zhang Riqing; Wang Xiaoyin; Zuo Lin; Liu Wei

    2000-01-01

    ischemic preconditioning (IPC) will protect the heart from the damage caused by a subsequent long ischemia period. 31 P spectra of isolated perfused rat heart measured by the nuclear magnetic resonance (NMR) surface coil technique can be used to continually, dynamically and noninvasively obtain metabolism information. This paper explores the IPC mechanisms by NMR. This study shows that IPC has no effect on enhancing the ATP and PCr levels during reperfusion but makes significantly slows and smooths the changes of intracellular pH and ATP during ischemia periods. The ATP and PCr recovery rate of the IPC group after ischemia is significantly higher than that of the control group. In conclusion, the above results support that IPC can protect the rat heart by reducing damage during the ischemia period

  6. Electrically controllable twisted-coiled artificial muscle actuators using surface-modified polyester fibers

    Science.gov (United States)

    Park, Jungwoo; Yoo, Ji Wang; Seo, Hee Won; Lee, Youngkwan; Suhr, Jonghwan; Moon, Hyungpil; Koo, Ja Choon; Ryeol Choi, Hyouk; Hunt, Robert; Kim, Kwang Jin; Kim, Soo Hyun; Nam, Jae-Do

    2017-03-01

    As a new class of thermally activated actuators based on polymeric fibers, we investigated polyethylene terephthalate (PET) yarns for the development of a twisted-coiled polymer fiber actuator (TCA). The PET yarn TCA exhibited the maximum linear actuation up to 8.9% by external heating at above the glass transition temperature, 160 °C-180 °C. The payload of the actuator was successfully correlated with the preload and training-load conditions by an empirical equation. Furthermore, the PET-based TCA was electrically driven by Joule heating after the PET surface was metallization with silver. For the fast and precise control of PET yarn TCA, electroless silver plating was conducted to form electrical conductive layers on the PET fiber surface. The silver plated PET-based TCA was tested by Joule heating and the tensile actuation was increased up to 12.1% (6 V) due to the enhanced surface hardness and slippage of PET fibers. Overall, silver plating of the polymeric yarn provided a fast actuation speed and enhanced actuation performance of the TCA actuator by Joule heating, providing a great potential for being used in artificial muscle for biomimetic machines including robots, industrial actuators and powered exoskeletons.

  7. Newly developed surface coil for endoluminal MRI, depiction of pig gastric wall layers and vascular architecture in ex vivo study.

    Science.gov (United States)

    Morita, Yoshinori; Kutsumi, Hiromu; Yoshinaka, Hayato; Matsuoka, Yuichiro; Kuroda, Kagayaki; Gotanda, Masakazu; Sekino, Naomi; Kumamoto, Etsuko; Yoshida, Masaru; Inokuchi, Hideto; Azuma, Takeshi

    2009-01-01

    The purpose of this study was to visualize the gastric wall layers and to depict the vascular architecture in vitro by using resected porcine stomachs studied with high-spatial resolution magnetic resonance (MR) imaging. Normal dissected porcine stomach samples (n = 4) were examined with a 3 Tesla MR system using a newly developed surface coil. MR images were obtained by the surface coil as receiver and a head coil as transmitter. High-spatial-resolution spin-echo MR images were obtained with a field of view of 8 x 8 cm, a matrix of 256 x 128 and slice thicknesses of 3 and 5 mm. T1 and T2-weighted MR images clearly depicted the normal porcine gastric walls as consisting of four distinct layers. In addition, vascular architectures in proper muscle layers were also visualized, which were confirmed by histological examinations to correspond to blood vessels. High-spatial-resolution MR imaging using a surface coil placed closely to the gastric wall enabled the differentiation of porcine gastric wall layers and the depiction of the blood vessels in proper muscle layer in this experimental study.

  8. Newly developed surface coil for endoluminal MRI, depiction of pig gastric wall layers and vascular architecture in ex vivo study

    International Nuclear Information System (INIS)

    Morita, Yoshinori; Kutsumi, Hiromu; Yoshinaka, Hayato

    2009-01-01

    The purpose of this study was to visualize the gastric wall layers and to depict the vascular architecture in vitro by using resected porcine stomachs studied with high-spatial resolution magnetic resonance (MR) imaging. Normal dissected porcine stomach samples (n=4) were examined with a 3 Tesla MR system using a newly developed surface coil. MR images were obtained by the surface coil as receiver and a head coil as transmitter. High-spatial-resolution spin-echo MR images were obtained with a field of view of 8 x 8 cm, a matrix of 256 x 128 and slice thicknesses of 3 and 5 mm. T1 and T2-weighted MR images clearly depicted the normal porcine gastric walls as consisting of four distinct layers. In addition, vascular architectures in proper muscle layers were also visualized, which were confirmed by histological examinations to correspond to blood vessels. High-spatial-resolution MR imaging using a surface coil placed closely to the gastric wall enabled the differentiation of porcine gastric wall layers and the depiction of the blood vessels in proper muscle layer in this experimental study. (author)

  9. Salecker-Wigner-Peres clock and average tunneling times

    International Nuclear Information System (INIS)

    Lunardi, Jose T.; Manzoni, Luiz A.; Nystrom, Andrew T.

    2011-01-01

    The quantum clock of Salecker-Wigner-Peres is used, by performing a post-selection of the final state, to obtain average transmission and reflection times associated to the scattering of localized wave packets by static potentials in one dimension. The behavior of these average times is studied for a Gaussian wave packet, centered around a tunneling wave number, incident on a rectangular barrier and, in particular, on a double delta barrier potential. The regime of opaque barriers is investigated and the results show that the average transmission time does not saturate, showing no evidence of the Hartman effect (or its generalized version).

  10. Preliminary results of endorectal surface coil magnetic resonance imaging for local staging of prostate cancer

    International Nuclear Information System (INIS)

    Jager, G.H.; Barentsz, J.O.; Rosette, J.J.M.C.H. de la; Rosenbusch, G.

    1994-01-01

    Objective: To evaluate the effectiveness of endorectal surface coil (ERC) magnetic resonance imaging (MRI) in the local staging of adenocarcinoma of the prostate (ACP). Materials and methods: A total of 23 patients who were considered candidates for radical prostatectomy because of clinically localized ACP were examined by ERC-MRI. All patients underwent laparoscopic or open lymph-node dissection prior to surgery. Four patients had positive lymph nodes at operation. A total of 19 underwant radical prostatectomy, allowing comparison of the MRI data with the surgical pathologic findings. Results: Twelve patients had extraglandular spread of ACP (T3) and 7 had locally confined ACP (T2). ERC-MRI predicted correctly a T3 tumor in 10 of 12 cases and a T2 tumor in 4 of 7 cases. ERC-MRI was 74% accurate in differentiating T2 from T3 tumor. Three cases of overestimation were in studies with poor image quality because of bowel movement motion artifacts. Conclusion: ERC-MRI was found to be a sensitive modality in staging clinically localized ACP. (orig.) [de

  11. Retinoblastoma - MR appearance using a surface coil in comparison with histopathological results

    Energy Technology Data Exchange (ETDEWEB)

    Lemke, Arne-Joern; Kazi, Iris; Mergner, Ulrike; Senfft von Pilsach, Marie-Isabell; Felix, Roland [Campus Virchow-Klinikum, Charite, Universitaetsmedizin Berlin, Berlin (Germany); Foerster, Paul I. [Universitaetsaugenklinik, Klinikum der Universitaet Muenchen-Innenstadt, Muenchen (Germany); Heimann, Heinrich; Bechrakis, Nikolaos; Foerster, Michael [Campus Benjamin-Franklin, Charite, Universitaetsmedizin Berlin, Berlin (Germany); Schueler, Andreas [Universitaetsaugenklinik Essen, Essen (Germany); Hosten, Norbert [Institut fuer Diagnostische Radiologie und Neuroradiologie, Klinikum der Ernst-Moritz-Arndt-Universitaets Greifswald, Greifswald (Germany)

    2007-01-15

    The purpose of this work was to evaluate the characteristic appearance of untreated retinoblastoma on a large sample in comparison to the histological findings after therapeutical enucleation. In a prospective clinical trial 46 children with retinoblastoma in 63 affected untreated eyes were examined under general anesthesia on MRI using a 1.5-T system. The examinations were performed with a special surface coil applying an examination protocol including fast T2- and T1-weighted spin echo sequences and additional fast T1-WI after intravenous injection of Gd-DTPA in different planes. The imaging results were compared to the histopathological findings in 29 patients with 30 affected eyes. Comparing MRI findings and histopathological results, optic nerve infiltration was detected with a sensitivity of 53.8% and a specificity of 82.3% on MRI, infiltration of the choroid with a sensitivity of 75.0% and a specificity of 100.0%, and the degree of tumor calcification with a sensitivity of 91.7% and a specificity of 88.9%. In this study the characteristic MR appearance of untreated retinoblastoma was evaluated. MRI was helpful in relevant aspects of pretherapeutical retinoblastoma staging, deficits remain regarding optic nerve infiltration. (orig.)

  12. In vivo MR imaging of the human skin at subnanoliter resolution using a superconducting surface coil at 1.5 Tesla.

    Science.gov (United States)

    Laistler, Elmar; Poirier-Quinot, Marie; Lambert, Simon A; Dubuisson, Rose-Marie; Girard, Olivier M; Moser, Ewald; Darrasse, Luc; Ginefri, Jean-Christophe

    2015-02-01

    To demonstrate the feasibility of a highly sensitive superconducting surface coil for microscopic MRI of the human skin in vivo in a clinical 1.5 Tesla (T) scanner. A 12.4-mm high-temperature superconducting coil was used at 1.5T for phantom and in vivo skin imaging. Images were inspected to identify fine anatomical skin structures. Signal-to-noise ratio (SNR) improvement by the high-temperature superconducting (HTS) coil, as compared to a commercial MR microscopy coil was quantified from phantom imaging; the gain over a geometrically identical coil made from copper (cooled or not) was theoretically deduced. Noise sources were identified to evaluate the potential of HTS coils for future studies. In vivo skin images with isotropic 80 μm resolution were demonstrated revealing fine anatomical structures. The HTS coil improved SNR by a factor 32 over the reference coil in a nonloading phantom. For calf imaging, SNR gains of 380% and 30% can be expected over an identical copper coil at room temperature and 77 K, respectively. The high sensitivity of HTS coils allows for microscopic imaging of the skin at 1.5T and could serve as a tool for dermatology in a clinical setting. © 2013 Wiley Periodicals, Inc.

  13. Local Multi-Channel RF Surface Coil versus Body RF Coil Transmission for Cardiac Magnetic Resonance at 3 Tesla: Which Configuration Is Winning the Game?

    OpenAIRE

    Weinberger, Oliver; Winter, Lukas; Dieringer, Matthias A.; Els, Antje; Oezerdem, Celal; Rieger, Jan; Kuehne, Andre; Cassara, Antonino M.; Pfeiffer, Harald; Wetterling, Friedrich; Niendorf, Thoralf

    2016-01-01

    INTRODUCTION: The purpose of this study was to demonstrate the feasibility and efficiency of cardiac MR at 3 Tesla using local four-channel RF coil transmission and benchmark it against large volume body RF coil excitation. METHODS: Electromagnetic field simulations are conducted to detail RF power deposition, transmission field uniformity and efficiency for local and body RF coil transmission. For both excitation regimes transmission field maps are acquired in a human torso phantom. For each...

  14. Image analysis from surface scanning with an absolute eddy current coil

    International Nuclear Information System (INIS)

    Attaoui, P.

    1994-01-01

    The aim of this work is to implement processing and analysis tools applied to eddy current imaging. These cartographies are issued from steam generator tubes testing using an absolute coil. The first is to eliminate the perturbations due to probe lift-off changes which generate low frequency oscillations on the image. The principle of the processing is to rebuild a complete surface of the noise using only the points around the defect area. The geometric origin of these perturbations led to a model based on sinusoidal functions. The method consists of gradually decomposing the image into a sum of basic sinusoidal surfaces. In order to take into account all kind of cartographies (especially rolling zone) some preprocessing must be applied. The results obtained with this 'cartography flattening'are satisfactory and the phase of analysis could begin with good condition of signal ratio. The second part of this work dealt with the choice and the perfection of image processing tools which would fit the most with the defect characterization. The aim of this characterization is to give the orientation and main size of the detected defect. A morphological skeleton representation has been chosen to illustrate the defect architecture and to allow sizing. A set of tools has been elaborated to obtain an (automatic) processing according to threshold. The results for single defect are satisfactory since the sizing error is around ± 25% and orientation is nearly always correctly given. The processing for area with several defects is more complex and new complementary research directions are proposed. (author)

  15. Determination of position and shape of flexible mri surface coils using the Microsoft Kinect for attenuation correction in PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Frohwein, Lynn; He, Mirco; Buther, Florian; Safers, Klaus [European Institute for Molecular Imaging, University of Muenster (Germany)

    2015-05-18

    Due to the varying position and shape of flexible MRI RF surface coils, the creation of attenuation maps for these coils is a challenging task. Nevertheless, coil material (metal, plastic, rubber) attenuates the PET signal to a considerable amount. Thus, including a coil μ-map into the human μ-map is essential. In this work, we present a method to determine the position and shape of flexible coils with the help of the Microsoft Kinect depth camera. Phantom PET/MRI (Siemens Biograph mMR) and CT scans (Siemens Biograph mCT) were performed with and without the flexible 32-channel coil equipped with 15 markers visible in CT and Kinect. Prior to the PET/MRI acquisition, Kinect data is acquired of the phantom with the coil on top. The manually extracted marker positions from CT and Kinect are used to non-rigidly transform the template CT according to the Kinect marker positions describing the shape of the coil during PET/MRI acquisition. An appropriate μ-map can then be calculated from the transformed CT dataset. Subsequently, the μ-map is placed in relation to the patient table according to the Kinect-derived marker positions. First results show that the coil shape can be determined with the help of the Kinect camera. The transformation of the template CT dataset according to Kinect marker positions during PET/MRI leads to appropriate results. Furthermore, the position of the coil can also be determined for an accurate placement of the μ-map in relation to the patient table. The determination of position and shape of flexible surface coils using the Kinect camera can be a way to include the CT-based coil μ-map in PET/MRI acquisitions without the need for additional MRI scans. Accuracy and practicability of the method have to be tested in further experiments.

  16. Determination of position and shape of flexible mri surface coils using the Microsoft Kinect for attenuation correction in PET/MRI

    International Nuclear Information System (INIS)

    Frohwein, Lynn; He, Mirco; Buther, Florian; Safers, Klaus

    2015-01-01

    Due to the varying position and shape of flexible MRI RF surface coils, the creation of attenuation maps for these coils is a challenging task. Nevertheless, coil material (metal, plastic, rubber) attenuates the PET signal to a considerable amount. Thus, including a coil μ-map into the human μ-map is essential. In this work, we present a method to determine the position and shape of flexible coils with the help of the Microsoft Kinect depth camera. Phantom PET/MRI (Siemens Biograph mMR) and CT scans (Siemens Biograph mCT) were performed with and without the flexible 32-channel coil equipped with 15 markers visible in CT and Kinect. Prior to the PET/MRI acquisition, Kinect data is acquired of the phantom with the coil on top. The manually extracted marker positions from CT and Kinect are used to non-rigidly transform the template CT according to the Kinect marker positions describing the shape of the coil during PET/MRI acquisition. An appropriate μ-map can then be calculated from the transformed CT dataset. Subsequently, the μ-map is placed in relation to the patient table according to the Kinect-derived marker positions. First results show that the coil shape can be determined with the help of the Kinect camera. The transformation of the template CT dataset according to Kinect marker positions during PET/MRI leads to appropriate results. Furthermore, the position of the coil can also be determined for an accurate placement of the μ-map in relation to the patient table. The determination of position and shape of flexible surface coils using the Kinect camera can be a way to include the CT-based coil μ-map in PET/MRI acquisitions without the need for additional MRI scans. Accuracy and practicability of the method have to be tested in further experiments.

  17. SU-E-J-239: Influence of RF Coil Materials On Surface and Buildup Dose From a 6MV Photon Beam

    Energy Technology Data Exchange (ETDEWEB)

    Ghila, A; Fallone, B; Rathee, S [Cross Cancer Institute, Edmonton, AB (United Kingdom)

    2015-06-15

    Purpose: In order to perform real time tumour tracking using an integrated Linac-MR, images have to be acquired during irradiation. MRI uses RF coils in close proximity to the imaged volume. Given current RF coil designs this means that the high energy photons will be passing through the coil before reaching the patient. This study experimentally investigates the dose modifications that occur due to the presence of various RF coil materials in the treatment beam. Methods: Polycarbonate, copper or aluminum tape, and Teflon were used to emulate the base, conductor and cover respectively of a surface RF coil. These materials were placed at various distances from the surface of polystyrene or solid water phantoms which were irradiated in the presence of no magnetic field, a transverse 0.2T magnetic field, and a parallel 0.2T magnetic field. Percent depth doses were measured using ion chambers. Results: A significant increase in surface and buildup dose is observed. The surface dose is seen to decrease with an increasing separation between the emulated coil and the phantom surface, when no magnetic field is present. When a transverse magnetic field is applied the surface dose decreases faster with increasing separation, as some of the electrons created in the coil are curved away from the phantom’s surface. When a parallel field is present the surface dose stays approximately constant for small separations, only slightly decreasing for separations greater than 5cm, since the magnetic field focuses the electrons produced in the coil materials not allowing them to scatter. Conclusion: Irradiating a patient through an RF coil leads to an increase in the surface and buildup doses. Mitigating this increase is important for the successful clinical use of either a transverse or a parallel configuration Linac-MR unit. This project is partially supported by an operating grant from the Canadian Institute of Health Research (CIHR MOP 93752)

  18. Research on Forming Mechanisms and Controlling Measurements for Surface Light Spot Defects of Galvanizing Steel Coils for Automobile Use

    Science.gov (United States)

    Guangmin, Wei; Haiyan, Sun; Jianqiang, Shi; Lianxuan, Wang; Haihong, Wu

    When producing high surface quality galvanizing steel coils for automobile use, there are always many light spots on the surface since Hansteel CGL No.1 has been put into operation. The defect samples were analyzed by SEM and EDS. The result shows that cause for light spot is not only one. There are more Mn and P in high strength auto sheet, which can result in difficulty to be cleaned off the oxide on the hot rolled coils, so the defects coming. This is why the defects come with high strength auto sheet. When coils galvanized, the defects can't be covered up. To the contrary, the defects will be more obvious when zinc growing on the surface. And sometimes zinc or residue can adhere to work rolls when strips passing through SPM. The deposits then press normal coating. So the light spots come more. When the defect comes from pressing, there is no defect on steel base. The causation is found and measures were taken including high pressure cleaning equipments adopted. Result shows that the defects disappeared.

  19. NCSX Trim Coil Design

    International Nuclear Information System (INIS)

    Kalish, M.; Brooks, A.; Rushinski, J.; Upcavage, R.

    2009-01-01

    The National Compact Stellarator Experiment (NCSX) was being constructed at the Princeton Plasma Physics Laboratory in partnership with Oak Ridge National Laboratory before work was stopped in 2008. The objective of this experiment was to develop the stellarator concept and evaluate it's potential as a model for future fusion power plants. Stellarator design requires very precisely positioned Modular Coils of complex shape to form 3D plasmas. In the design of NCSX, Trim Coils were required to compensate for both the positioning of the coils during assembly and the fabrication tolerances of the Modular Coils. Use of the Trim Coils allowed for larger tolerances increasing ease of assembly and decreasing overall cost. A set of Trim coils was developed to suppress the toroidal flux in island regions due to misalignment, magnetic materials, and eddy currents. The requirement imposed upon the design forced the toroidal flux in island regions below 10% of the total toroidal flux in the plasma. An analysis was first performed to evaluate candidate Trim Coil configurations iterating both the size, number, and position of the coils. The design was optimized considering both performance and cost while staying within the tight restraints presented by the space limited geometry. The final design of the Trim Coils incorporated a 48 Coil top bottom symmetric set. Fabrication costs were minimized by having only two coil types and using a planar conventional design with off the shelf commercial conductor. The Trim Coil design incorporated supports made from simple structural shapes assembled together in a way which allowed for adjustment as well as accommodation for the tolerance build up on the mating surfaces. This paper will summarize the analysis that led to the optimization of the Trim Coils set, the trim coil mechanical design, thermal and stress analysis, and the design of the supporting Trim Coil structure

  20. Design and application of surface coils for MR imaging with consideration of patient safety

    International Nuclear Information System (INIS)

    Bader, R.; Zabel, H.J.; Gehrig, J.; Lorenz, W.J.

    1987-01-01

    Problems concerning the safety of the patient have arisen by increasing the magnetic field for MR imaging and MR spectroscopy up to 2 T. High electric potentials result on the radio frequency (RF) that antennas in some cases are situated directly on or even inside the body. Transmit pulses can induce high voltages and currents in a separate receiver coil being resonant. Intensive RF fields emerging from the receiver coil may severely heat the conductive body tissue. Principles for suppressing the induced voltages and for detuning the antenna are described. General rules for the design of antennas and their application are discussed

  1. Laps ja pere vajavad enam tähelepanu / Anne Tiko

    Index Scriptorium Estoniae

    Tiko, Anne, 1949-

    2001-01-01

    Lääne-Viru Maavalitsuse, Lastekaitse Liidu ja TPÜ sotsiaaltöö osakonna korraldatud kuuenda vabariikliku lastekaitsekonverentsi "Laps ja pere tänases Eestis" pöördumine haridus- ja sotsiaalministeeriumi poole

  2. President Ilves ja Simon Peres avasid Tallinna uue sünagoogi / Evely Baum, Riina Leminsky

    Index Scriptorium Estoniae

    Baum, Evely

    2007-01-01

    16. mail 2007 avati pidulikult Tallinna uus juudi sünagoog. Avamistseremoonial osalesid ka Eesti president Toomas Hendrik Ilves ja peaminister Andrus Ansip, Iisraeli asepeaminister Simon Peres, Iisraeli pearabi Yona Metzger, Venemaa pearabi Berl Lazar

  3. High-resolution MR imaging of the carpal tunnel and the wrist. Application of a 5-cm surface coil

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, J.; Bleschkowski, A.; Tempka, A.; Felix, R. [Medical Faculty of the Humboldt Univ., Berlin (Germany). Dept. of Radiology

    2000-07-01

    In order to make a comparative analysis of transversal tomograms obtained by high-resolution MR imaging with frozen cross-sections of an anatomical forearm specimen, twenty-two healthy volunteers were also examined using the same coil system to test for a range of possible clinical applications and for the depiction of morphological and morphometrical values of normal anatomy in vivo. MR images of the carpal tunnel of 22 healthy volunteers were obtained with a 1.5-T whole-body system with a 5-cm surface coil. Measurements were recorded with a field-of-view between 50x50 mm{sup 2} and 60x60 mm{sup 2} in a 256x256 pixel matrix for the T1 sequence. A slice thickness of 2 mm was used. The images were acquired using a T1-weighted SE sequence (TR/TE 500/38 ms) and a T2-weighted SE sequence (TR/TE 2000/70 ms). Additionally, a formalin-fixed anatomical forearm specimen was imaged for anatomic correlation. The imaged transversal cross-section levels in the specimen were subsequently freeze-sectioned. The anatomical structures of the MR findings were identified and compared with the macroscopical sections of the specimen. Based on the good depiction of details at this coil system with a pixel size in T1 of 0.195x0.195 mm, high-resolution MR imaging enabled identification of the interior structures of the carpal tunnel, as well as delineation of connective tissue. The clinical value of high-resolution MR includes the diagnosis of carpal tunnel syndrome and inflammatory disorders of the wrist. Our results support the feasibility of high-resolution MR imaging of the carpal tunnel and the wrist using small surface coils.

  4. High-resolution MR imaging of the carpal tunnel and the wrist. Application of a 5-cm surface coil

    International Nuclear Information System (INIS)

    Maurer, J.; Bleschkowski, A.; Tempka, A.; Felix, R.

    2000-01-01

    In order to make a comparative analysis of transversal tomograms obtained by high-resolution MR imaging with frozen cross-sections of an anatomical forearm specimen, twenty-two healthy volunteers were also examined using the same coil system to test for a range of possible clinical applications and for the depiction of morphological and morphometrical values of normal anatomy in vivo. MR images of the carpal tunnel of 22 healthy volunteers were obtained with a 1.5-T whole-body system with a 5-cm surface coil. Measurements were recorded with a field-of-view between 50x50 mm 2 and 60x60 mm 2 in a 256x256 pixel matrix for the T1 sequence. A slice thickness of 2 mm was used. The images were acquired using a T1-weighted SE sequence (TR/TE 500/38 ms) and a T2-weighted SE sequence (TR/TE 2000/70 ms). Additionally, a formalin-fixed anatomical forearm specimen was imaged for anatomic correlation. The imaged transversal cross-section levels in the specimen were subsequently freeze-sectioned. The anatomical structures of the MR findings were identified and compared with the macroscopical sections of the specimen. Based on the good depiction of details at this coil system with a pixel size in T1 of 0.195x0.195 mm, high-resolution MR imaging enabled identification of the interior structures of the carpal tunnel, as well as delineation of connective tissue. The clinical value of high-resolution MR includes the diagnosis of carpal tunnel syndrome and inflammatory disorders of the wrist. Our results support the feasibility of high-resolution MR imaging of the carpal tunnel and the wrist using small surface coils

  5. Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils

    Science.gov (United States)

    Hanvey, S.; Glegg, M.; Foster, J.

    2009-09-01

    This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

  6. Capsule of parotid gland tumor: evaluation by 3.0 T magnetic resonance imaging using surface coils

    International Nuclear Information System (INIS)

    Ishibashi, Mana; Fujii, Shinya; Nishihara, Keisuke; Matsusue, Eiji; Kodani, Kazuhiko; Kaminou, Toshio; Ogawa, Toshihide; Kawamoto, Katsuyuki

    2010-01-01

    Background: Magnetic resonance (MR) imaging of parotid gland tumors has been widely reported, although few reports have evaluated the capsule of parotid gland tumors in detail. Purpose: To evaluate the diagnostic usefulness of 3.0 T MR imaging with surface coils for detection of the parotid gland tumor capsule, and to clarify the characteristics of the capsules. Material and Methods: Seventy-eight patients with parotid gland tumors (63 benign and 15 malignant) were evaluated. Axial and coronal T2-weighted and contrast-enhanced T1-weighted images were obtained using a 3.0 T MR scanner with 70 mm surface coils. It was retrospectively assessed whether each parotid gland tumor was completely surrounded by a capsule. The capsule was classified as regular or irregular in terms of capsular thickness, and as none, mildly, or strongly enhancing in terms of contrast enhancement. Visual interpretations were compared with histopathological findings to evaluate the diagnostic ability of MR imaging to detect parotid gland tumor capsules. Statistical evaluation was conducted concerning the presence of capsules, capsular irregularity, and the difference in contrast enhancement between benign and malignant tumors, and that between pleomorphic adenomas and Warthin's tumors. Results: Capsules completely surrounding the tumor on MR imaging yielded a sensitivity of 87.7% (50/57), specificity of 90.5% (19/21), and accuracy of 88.5% (69/78). Benign tumors had a capsule completely surrounding the tumor significantly more often than malignant tumors (P = 0.009). Concerning capsular irregularity, malignant tumors tended to have more irregular capsules than benign tumors, although there were no significant differences. The capsules of malignant tumors enhanced significantly more strongly than those of benign tumors (P = 0.018). Conclusion: 3.0 T MR imaging using surface coils could correctly depict parotid gland tumor capsules in most cases. Most benign and some malignant tumors had capsules

  7. Liquid rope coiling

    NARCIS (Netherlands)

    Ribe, N.M.; Habibi, M.; Bonn, D.

    2012-01-01

    A thin stream or rope of viscous fluid falling from a sufficient height onto a surface forms a steadily rotating helical coil. Tabletop laboratory experiments in combination with a numerical model for slender liquid ropes reveal that finite-amplitude coiling can occur in four distinct regimes

  8. MR findings of facial nerve on oblique sagittal MRI using TMJ surface coil: normal vs peripheral facial nerve palsy

    International Nuclear Information System (INIS)

    Park, Yong Ok; Lee, Myeong Jun; Lee, Chang Joon; Yoo, Jeong Hyun

    2000-01-01

    To evaluate the findings of normal facial nerve, as seen on oblique sagittal MRI using a TMJ (temporomandibular joint) surface coil, and then to evaluate abnormal findings of peripheral facial nerve palsy. We retrospectively reviewed the MR findings of 20 patients with peripheral facial palsy and 50 normal facial nerves of 36 patients without facial palsy. All underwent oblique sagittal MRI using a T MJ surface coil. We analyzed the course, signal intensity, thickness, location, and degree of enhancement of the facial nerve. According to the angle made by the proximal parotid segment on the axis of the mastoid segment, course was classified as anterior angulation (obtuse and acute, or buckling), straight and posterior angulation. Among 50 normal facial nerves, 24 (48%) were straight, and 23 (46%) demonstrated anterior angulation; 34 (68%) showed iso signal intensity on T1W1. In the group of patients, course on the affected side was either straight (40%) or showed anterior angulation (55%), and signal intensity in 80% of cases was isointense. These findings were similar to those in the normal group, but in patients with post-traumatic or post-operative facial palsy, buckling, of course, appeared. In 12 of 18 facial palsy cases (66.6%) in which contrast materials were administered, a normal facial nerve of the opposite facial canal showed mild enhancement on more than one segment, but on the affected side the facial nerve showed diffuse enhancement in all 14 patients with acute facial palsy. Eleven of these (79%) showed fair or marked enhancement on more than one segment, and in 12 (86%), mild enhancement of the proximal parotid segment was noted. Four of six chronic facial palsy cases (66.6%) showed atrophy of the facial nerve. When oblique sagittal MR images are obtained using a TMJ surface coil, enhancement of the proximal parotid segment of the facial nerve and fair or marked enhancement of at least one segment within the facial canal always suggests pathology of

  9. Diagnostic accuracy of surface coil MRI in assessing cartilaginous invasion in laryngeal tumours. Do we need contrast-agent administration?

    International Nuclear Information System (INIS)

    Preda, Lorenzo; Conte, Giorgio; Bonello, Luke; Giannitto, Caterina; Tagliabue, Elena; Raimondi, Sara; Ansarin, Mohssen; De Benedetto, Luigi; Cattaneo, Augusto; Maffini, Fausto; Bellomi, Massimo

    2017-01-01

    To assess the diagnostic accuracy of MRI performed using surface coils, with and without contrast medium, in predicting thyroid and cricoid cartilage infiltration in laryngeal tumours, and to investigate whether the radiologist's experience influences diagnostic accuracy. We retrospectively enrolled patients with biopsy-proven laryngeal cancer who had undergone preoperative staging MRI and open surgery. Two radiologists with different experience (senior vs. junior) reviewed the MR images without (session A1) and with contrast medium (session A2) separately. We calculated the accuracy of MRI with and without contrast medium in detecting infiltration of the thyroid and cricoid cartilages. Interobserver agreement was calculated by Cohen's Kappa (k). Forty-two patients were enrolled, for a total of 62 cartilages. In session A1 the senior and junior radiologists showed an accuracy of 85% and 71%, respectively, with k = 0.53 (0.33-0.72). In session A2 the senior and junior radiologists showed an accuracy of 84% and 77%, respectively, with k = 0.68 (0.49-0.86). Staging of laryngeal tumours with surface coil MRI showed good diagnostic accuracy in assessing cartilaginous infiltration. We observed similar values of diagnostic accuracy for the analysis performed with and without contrast medium for the senior radiologist. (orig.)

  10. Diagnostic accuracy of surface coil MRI in assessing cartilaginous invasion in laryngeal tumours. Do we need contrast-agent administration?

    Energy Technology Data Exchange (ETDEWEB)

    Preda, Lorenzo [Universita degli Studi di Pavia, Department of Clinical-Surgical Diagnostic and Pediatric Sciences, Pavia (Italy); Division of Radiology, National Center of Oncological Hadrontherapy (CNAO Foundation), Pavia (Italy); Conte, Giorgio [Universita degli Studi di Milano, Postgraduation School in Radiodiagnostics, Milan (Italy); Bonello, Luke [Division of Radiology, Poliambulanza Hospital, Brescia (Italy); Giannitto, Caterina [European Institute of Oncology, Division of Radiology, Milan (Italy); Tagliabue, Elena; Raimondi, Sara [European Institute of Oncology, Division of Epidemiology and Biostatistics, Milan (Italy); Ansarin, Mohssen; De Benedetto, Luigi; Cattaneo, Augusto [European Institute of Oncology, Division of Head and Neck Surgery, Milan (Italy); Maffini, Fausto [European Institute of Oncology, Division of Pathology, Milan (Italy); Bellomi, Massimo [European Institute of Oncology, Division of Radiology, Milan (Italy); Universita degli Studi di Milano, Oncology and Haematology/Oncology Department, Milan (Italy)

    2017-11-15

    To assess the diagnostic accuracy of MRI performed using surface coils, with and without contrast medium, in predicting thyroid and cricoid cartilage infiltration in laryngeal tumours, and to investigate whether the radiologist's experience influences diagnostic accuracy. We retrospectively enrolled patients with biopsy-proven laryngeal cancer who had undergone preoperative staging MRI and open surgery. Two radiologists with different experience (senior vs. junior) reviewed the MR images without (session A1) and with contrast medium (session A2) separately. We calculated the accuracy of MRI with and without contrast medium in detecting infiltration of the thyroid and cricoid cartilages. Interobserver agreement was calculated by Cohen's Kappa (k). Forty-two patients were enrolled, for a total of 62 cartilages. In session A1 the senior and junior radiologists showed an accuracy of 85% and 71%, respectively, with k = 0.53 (0.33-0.72). In session A2 the senior and junior radiologists showed an accuracy of 84% and 77%, respectively, with k = 0.68 (0.49-0.86). Staging of laryngeal tumours with surface coil MRI showed good diagnostic accuracy in assessing cartilaginous infiltration. We observed similar values of diagnostic accuracy for the analysis performed with and without contrast medium for the senior radiologist. (orig.)

  11. Magnetic resonance imaging in ophthalmic diagnosis. Results of examinations using a small field-of-view surface coil

    International Nuclear Information System (INIS)

    Kato, Yuji; Yoshida, Akitoshi; Kanno, Harumi; Ogasawara, Hironobu; Murakami, Noboru; Cheng, Hong-Ming.

    1997-01-01

    We obtained T 1 -and T 2 -weighted magnetic resonance (MR) images in 3 patients with vitreoretinal disorders using a recently developed surface coil that was inductively coupled and had a small field of view. On both T 1 -and T 2 -weighted images, tractional retinal detachment was clearly detected in the first patient, who had proliferative diabetic retinopathy. T 1 - and T 2 -weighted images of the second patient, who had total retinal detachment with proliferative vitreous retinopathy, revealed a funnel-shaped thickened retina. The third patient had postoperative rhegmatogenous retinal detachment with opacity due to postoperative cataract and intravitreous injection of gas; on this patient's MR images we could clearly differentiate the reattached retina, silicone used for scleral buckling, and intravitreous gas, even though these differentiations were not possible with ophthalmoscopy or B-scan ultrasonography. High resolution MR imaging with our technique can be performed in a short time and regardless of the eye's condition. Our findings strongly indicate that MRI with a small field-of-view surface coil is a useful tool for diagnosing various vitreoretinal disorders and observing pathological changes. (author)

  12. Tilt optimized flip uniformity (TOFU) RF pulse for uniform image contrast at low specific absorption rate levels in combination with a surface breast coil at 7 Tesla.

    Science.gov (United States)

    van Kalleveen, Irene M L; Boer, Vincent O; Luijten, Peter R; Klomp, Dennis W J

    2015-08-01

    Going to ultrahigh field MRI (e.g., 7 Tesla [T]), the nonuniformity of the B1+ field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B1+, its field remains nonuniform. In this work, an RF pulse was designed that uses the slab selection to compensate the inhomogeneous B1+ field of a surface coil without a substantial increase in specific absorption rate (SAR). A breast surface coil was used with a decaying B1+ field in the anterior-posterior direction of the human breast. Slab selective RF pulses were designed and compared with adiabatic and spokes RF pulses. Proof of principle was demonstrated with FFE and B1+ maps of the human breast. In vivo measurements obtained with the breast surface coil show that the tilt optimized flip uniformity (TOFU) RF pulses can improve the flip angle homogeneity by 31%, while the SAR will be lower compared with BIR-4 and spokes RF pulses. By applying TOFU RF pulses to the breast surface coil, we are able to compensate the inhomogeneous B1+ field, while keeping the SAR low. Therefore stronger T1 -weighting in FFE sequences can be obtained, while pulse durations can remain short, as shown in the human breast at 7T. © 2014 Wiley Periodicals, Inc.

  13. High-resolution MRI using orbit surface coils for the evaluation of metastatic risk factors in 143 children with retinoblastoma. Part 2: new vs. old imaging concept

    Energy Technology Data Exchange (ETDEWEB)

    Sirin, Selma; Schlamann, Marc; Schweiger, Bernd; Goericke, Sophia L. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Metz, Klaus A. [University Hospital Essen, Department of Pathology and Neuropathology, Essen (Germany); Bornfeld, Norbert; Holdt, Markus [University Hospital Essen, Department of Ophthalmology, Essen (Germany); Temming, Petra; Schuendeln, Michael M. [University Hospital Essen, Department of Pediatric Hematology and Oncology, Essen (Germany)

    2015-08-15

    High-resolution magnetic resonance imaging (MRI) is recommended for the evaluation of metastatic risk factors in children with retinoblastoma according to recent guidelines. The aim of this study was to compare diagnostic accuracy of a new imaging concept with two orbit surface coils to that of an old imaging concept with one orbit surface coil. One hundred forty-three patients (148 eyes, 64 girls, 79 boys) underwent high-resolution MRI on 1.5 T scanners using orbit surface coils. The old imaging concept (one orbit surface coil focusing on the (most) effected eye additionally to the standard head coil) was used in 100 patients/103 eye; the new imaging concept (two orbit surface coils (each focusing on one eye) additionally to the standard head coil) in 43 patients/45 eyes. Image analysis was performed by two neuroradiologists in consensus. Histopathology served as gold standard. Detection rate for choroidal invasion was higher for the new compared to that for the old imaging concept (sensitivity/specificity 87.5/94.6 % vs. 57.1/96.1 % for choroidal invasion and 100/97.5 % vs. 58.3/97.7 % for massive choroidal invasion, respectively). Sensitivity and specificity for the detection of postlaminar optic nerve infiltration, peribulbar fat, and scleral invasion were comparable in both imaging concepts; however positive predictive value was higher in the new imaging concept (new vs. old imaging concept: 60 vs. 31.6 % for postlaminar and deep postlaminar optic nerve infiltration, respectively, and 100 vs. 66.7 % for scleral invasion). The new imaging concept shows a trend towards improving the accuracy of detecting metastatic risk factors in children with retinoblastoma and is therefore recommended for pretherapeutic imaging and follow-up. (orig.)

  14. High-resolution MRI using orbit surface coils for the evaluation of metastatic risk factors in 143 children with retinoblastoma. Part 2: new vs. old imaging concept

    International Nuclear Information System (INIS)

    Sirin, Selma; Schlamann, Marc; Schweiger, Bernd; Goericke, Sophia L.; Metz, Klaus A.; Bornfeld, Norbert; Holdt, Markus; Temming, Petra; Schuendeln, Michael M.

    2015-01-01

    High-resolution magnetic resonance imaging (MRI) is recommended for the evaluation of metastatic risk factors in children with retinoblastoma according to recent guidelines. The aim of this study was to compare diagnostic accuracy of a new imaging concept with two orbit surface coils to that of an old imaging concept with one orbit surface coil. One hundred forty-three patients (148 eyes, 64 girls, 79 boys) underwent high-resolution MRI on 1.5 T scanners using orbit surface coils. The old imaging concept (one orbit surface coil focusing on the (most) effected eye additionally to the standard head coil) was used in 100 patients/103 eye; the new imaging concept (two orbit surface coils (each focusing on one eye) additionally to the standard head coil) in 43 patients/45 eyes. Image analysis was performed by two neuroradiologists in consensus. Histopathology served as gold standard. Detection rate for choroidal invasion was higher for the new compared to that for the old imaging concept (sensitivity/specificity 87.5/94.6 % vs. 57.1/96.1 % for choroidal invasion and 100/97.5 % vs. 58.3/97.7 % for massive choroidal invasion, respectively). Sensitivity and specificity for the detection of postlaminar optic nerve infiltration, peribulbar fat, and scleral invasion were comparable in both imaging concepts; however positive predictive value was higher in the new imaging concept (new vs. old imaging concept: 60 vs. 31.6 % for postlaminar and deep postlaminar optic nerve infiltration, respectively, and 100 vs. 66.7 % for scleral invasion). The new imaging concept shows a trend towards improving the accuracy of detecting metastatic risk factors in children with retinoblastoma and is therefore recommended for pretherapeutic imaging and follow-up. (orig.)

  15. Practical design of a 4 Tesla double-tuned RF surface coil for interleaved 1H and 23Na MRI of rat brain.

    Science.gov (United States)

    Alecci, M; Romanzetti, S; Kaffanke, J; Celik, A; Wegener, H P; Shah, N J

    2006-08-01

    MRI is proving to be a very useful tool for sodium quantification in animal models of stroke, ischemia, and cancer. In this work, we present the practical design of a dual-frequency RF surface coil that provides (1)H and (23)Na images of the rat head at 4 T. The dual-frequency RF surface coil comprised of a large loop tuned to the (1)H frequency and a smaller co-planar loop tuned to the (23)Na frequency. The mutual coupling between the two loops was eliminated by the use of a trap circuit inserted in the smaller coil. This independent-loop design was versatile since it enabled a separate optimisation of the sensitivity and RF field distributions of the two coils. To allow for an easy extension of this simple double-tuned coil design to other frequencies (nuclei) and dimensions, we describe in detail the practical aspects of the workbench design and MRI testing using a phantom that mimics in vivo conditions. A comparison between our independent-loop, double-tuned coil and a single-tuned (23)Na coil of equal size obtained with a phantom matching in vivo conditions, showed a reduction of the (23)Na sensitivity (about 28 %) because of signal losses in the trap inductance. Typical congruent (1)H and (23)Na rat brain images showing good SNR ((23)Na: brain 7, ventricular cerebrospinal fluid 11) and spatial resolution ((23)Na: 1.25 x 1.25 x 5mm(3)) are also reported. The in vivo SNR values obtained with this coil were comparable to, if not better than, other contemporary designs in the literature.

  16. Parallel image-acquisition in continuous-wave electron paramagnetic resonance imaging with a surface coil array: Proof-of-concept experiments

    Science.gov (United States)

    Enomoto, Ayano; Hirata, Hiroshi

    2014-02-01

    This article describes a feasibility study of parallel image-acquisition using a two-channel surface coil array in continuous-wave electron paramagnetic resonance (CW-EPR) imaging. Parallel EPR imaging was performed by multiplexing of EPR detection in the frequency domain. The parallel acquisition system consists of two surface coil resonators and radiofrequency (RF) bridges for EPR detection. To demonstrate the feasibility of this method of parallel image-acquisition with a surface coil array, three-dimensional EPR imaging was carried out using a tube phantom. Technical issues in the multiplexing method of EPR detection were also clarified. We found that degradation in the signal-to-noise ratio due to the interference of RF carriers is a key problem to be solved.

  17. Ressonância magnética das vias lacrimais: estudo comparativo entre bobinas de superfície convencionais e microscópicas Magnetic resonance dacryocystography: comparison between conventional surface coils and microscopic coils

    Directory of Open Access Journals (Sweden)

    Luiz de Abreu Junior

    2008-08-01

    Full Text Available OBJETIVO: A ressonância magnética tem sido utilizada para avaliar as vias lacrimais, com vantagens em relação à dacriocistografia por raios-X. O objetivo deste trabalho é obter imagens de alta resolução utilizando bobinas de superfície microscópicas para avaliação de estruturas normais das vias lacrimais, comparando com o aspecto observado utilizando-se bobinas de superfície convencionais. MATERIAIS E MÉTODOS: Cinco voluntários assintomáticos, sem histórico de lacrimejamento, submeteram-se a ressonância magnética de alto campo, com bobinas de superfície (convencional e microscópica, com seqüência STIR após instilação de soro fisiológico. A identificação das estruturas anatômicas normais das vias lacrimais foi comparada utilizando-se as duas bobinas. Mediante uso de um sistema de escore, um valor médio de cada estrutura foi calculado por dois examinadores, consensualmente. RESULTADOS: Em 90% das vezes houve aumento do escore, atribuído à estrutura anatômica no estudo com a bobina microscópica. Em média, houve aumento de 1,17 ponto no escore, por estrutura anatômica visualizada, quando se utilizou a bobina microscópica. Observou-se, ainda, melhora subjetiva da relação sinal-ruído ao se utilizar a bobina microscópica. CONCLUSÃO: A dacriocistografia por ressonância magnética com bobinas microscópicas é um método adequado para o estudo das vias lacrimais, resultando em imagens de melhor qualidade quando comparada ao uso de bobinas de superfície convencionais.OBJECTIVE: Magnetic resonance imaging has been utilized in the evaluation of the lacrimal apparatus with some advantages over conventional dacryocystography. The present study was aimed at acquiring high-resolution images utilizing microscopic coils for evaluating typical structures of the lacrimal apparatus as compared with the findings observed with conventional surface coils. MATERIALS AND METHODS: Five asymptomatic volunteers with no history of

  18. High-resolution MR imaging of the elbow using a microscopy surface coil and a clinical 1.5 T MR machine: preliminary results

    International Nuclear Information System (INIS)

    Yoshioka, Hiroshi; Ueno, Teruko; Takahashi, Nobuyuki; Saida, Yukihisa; Tanaka, Toshikazu; Kujiraoka, Yuka; Shindo, Masashi; Nishiura, Yasumasa; Ochiai, Naoyuki

    2004-01-01

    To obtain high-resolution MR images of the elbow using a microscopy surface coil with a 1.5 T clinical machine and to evaluate the feasibility of its use for elbow injuries. Five asymptomatic normal volunteers and 13 patients with elbow pain were prospectively studied with MR imaging using a microscopy surface coil 47 mm in diameter. High-resolution MR images using a microscopy coil were obtained with fast spin echo (FSE) proton density-weighted sequence, gradient recalled echo (GRE) T2*-weighted sequence, and short tau inversion recovery (STIR) sequence, with a 1-2 mm slice thickness, a 50-70 mm field of view, an imaging matrix of 140-224 x 512 using zero fill interpolation, and 2-6 excitations. High-resolution MR images of normal volunteers using a microscopy coil clearly showed each structure of the medial and lateral collateral ligaments on GRE T2*-weighted images and FSE proton-density weighted images. Partial medial collateral ligament injury, a small avulsion of the medial epicondyle, and osteochondritis dissecans were well demonstrated on high-resolution MR images. High-resolution MR imaging of the elbow using a microscopy surface coil with a 1.5 T clinical machine is a promising method for accurately characterizing the normal anatomy of the elbow and depicting its lesions in detail. (orig.)

  19. Cardiac MRI in mice at 9.4 Tesla with a transmit-receive surface coil and a cardiac-tailored intensity-correction algorithm.

    Science.gov (United States)

    Sosnovik, David E; Dai, Guangping; Nahrendorf, Matthias; Rosen, Bruce R; Seethamraju, Ravi

    2007-08-01

    To evaluate the use of a transmit-receive surface (TRS) coil and a cardiac-tailored intensity-correction algorithm for cardiac MRI in mice at 9.4 Tesla (9.4T). Fast low-angle shot (FLASH) cines, with and without delays alternating with nutations for tailored excitation (DANTE) tagging, were acquired in 13 mice. An intensity-correction algorithm was developed to compensate for the sensitivity profile of the surface coil, and was tailored to account for the unique distribution of noise and flow artifacts in cardiac MR images. Image quality was extremely high and allowed fine structures such as trabeculations, valve cusps, and coronary arteries to be clearly visualized. The tag lines created with the surface coil were also sharp and clearly visible. Application of the intensity-correction algorithm improved signal intensity, tissue contrast, and image quality even further. Importantly, the cardiac-tailored properties of the correction algorithm prevented noise and flow artifacts from being significantly amplified. The feasibility and value of cardiac MRI in mice with a TRS coil has been demonstrated. In addition, a cardiac-tailored intensity-correction algorithm has been developed and shown to improve image quality even further. The use of these techniques could produce significant potential benefits over a broad range of scanners, coil configurations, and field strengths. (c) 2007 Wiley-Liss, Inc.

  20. Compact stellarator coils

    International Nuclear Information System (INIS)

    Pomphrey, N.; Berry, L.A.; Boozer, A.H.

    2001-01-01

    Experimental devices to study the physics of high-beta (β>∼4%), low aspect ratio (A<∼4.5) stellarator plasmas require coils that will produce plasmas satisfying a set of physics goals, provide experimental flexibility, and be practical to construct. In the course of designing a flexible coil set for the National Compact Stellarator Experiment, we have made several innovations that may be useful in future stellarator design efforts. These include: the use of Singular Value Decomposition methods for obtaining families of smooth current potentials on distant coil winding surfaces from which low current density solutions may be identified; the use of a Control Matrix Method for identifying which few of the many detailed elements of the stellarator boundary must be targeted if a coil set is to provide fields to control the essential physics of the plasma; the use of Genetic Algorithms for choosing an optimal set of discrete coils from a continuum of potential contours; the evaluation of alternate coil topologies for balancing the tradeoff between physics objective and engineering constraints; the development of a new coil optimization code for designing modular coils, and the identification of a 'natural' basis for describing current sheet distributions. (author)

  1. Tilt optimized flip uniformity (TOFU) RF pulse for uniform image contrast at low specific absorption rate levels in combination with a surface breast coil at 7 Tesla

    NARCIS (Netherlands)

    van Kalleveen, Irene M. L.; Boer, VO; Luijten, Peter R.; Klomp, DWJ

    Purpose: Going to ultrahigh field MRI (e. g., 7 Tesla [ T]), the nonuniformity of the B_1 field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B_1, its field remains nonuniform. In this work, an RF pulse was designed

  2. Commercial applications for COIL

    Science.gov (United States)

    Solomon, Wayne C.; Carroll, David L.; King, D. M.; Fockler, L. A.; Stromberg, D. S.; Sexauer, M.; Milmoe, A.; Sentman, Lee H.

    2000-01-01

    The chemical oxygen-iodine laser (COIL) is a high power, fiber deliverable tool, which can be used for a number of different industrial applications. COIL is of particular interest because of its short fiber deliverable wavelength, high scaleable continuous wave power, and excellent material interaction properties. In past research the University of Illinois at Urbana-Champaign identified and decommissioning and decontamination (DD) of nuclear facilities as a primary focus for COIL technology. DD will be a major challenge in the coming decades. The use of a robotically driven fiber delivered cutting/ablation tool in contaminated areas promises to lower risks to workers for the DD mission. Further, the high cutting speed of COIL will significantly reduce the time required to cut contaminated equipment, reducing costs. The high power of COIL will permit the dismantling of thick stacks of piping and equipment as well as reactor vessels. COIL is very promising for the removal of material from contaminated surfaces, perhaps to depths thicker than an inch. Laser cutting and ablation minimizes dust and fumes, which reduces the required number of high efficiency particulate accumulator filters, thus reducing costly waste disposal. Other potential industrial applications for COIL are shipbuilding, automotive manufacturing, heavy machinery manufacturing, tasks requiring underwater cutting or welding, and there appear to be very promising applications for high powers lasers in the oil industry.

  3. Structural and spectroscopic characterisations of the surface oxide scales and inclusions present on edge-burst hot-rolled steel coils

    International Nuclear Information System (INIS)

    Chowdhury, Anirban; Iyyappan, Ramasamy; Majumdar, Dipanwita; Singha, Achintya

    2014-01-01

    Detailed structural and spectroscopic characterisations have been carried out on the inclusions and the surface oxides present on edge-burst hot-rolled steel coils. Surface scales were characterised through X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. Evidence of different types of regular and non-stoichiometric Fe-oxides was found on the cracked surface of the steel wire. Along with the surface scales inclusions with calcium aluminate and spinel was characterized using Raman spectroscopy. The usefulness of Raman spectroscopy has been explored in detail for the characterisation of these inclusions; especially when XRD information ceases to be a limiting tool. The samples collected from the clogged nozzle area were found to be of grossite (CaO·2Al 2 O 3 ) phase and this was also observed in the inclusions in the finished coils. It was found that this particular calcium aluminate phase has a detrimental effect on casting and final finished steel products. - Highlights: • First investigation and surface study report on edge-bursting issue of steel coils. • Detailed characterisations of the inclusions and surface oxide scales in steel. • Influence of a particular type of calcium aluminate phase on process chemistry

  4. MRI of prostate zonal anatomy with an endorectal surface coil; Anatomie zonale de la prostate par IRM endorectale

    Energy Technology Data Exchange (ETDEWEB)

    Cornud, F.; Belin, X.; Melki, P.; Helenon, O.; Cretien, Y.; Dufour, B.; Moreau, J.F. [Hopital Necker-Enfants-Malades, 75 - Paris (France)

    1995-01-01

    The development of an endorectal surface coil now permits a partial study of the anatomical model developed by McNeal. Axial and coronal views, which were used to establish the model can be obtained in a short period of time with fast spin echo sequences. Axial views are performed along the proximal urethra and coronal views are performed along the axis of the distal urethra and the ejaculatory duts. Anatomical boundaries of the transitional zone are well delineated on axial views, illustrating the concept of `inner gland`. The prostatic capsule and the neuro-vascular bundles, pathways of extension of the cancer out of the prostate are also well delineated. Coronal sections allow a very good anatomical study of the caudal junction of the vas deferens and the seminal vesicles (the so called weak space), pathway of tumor extension to the seminal vesicles. Differences in signal of the prostatic zones make the outer gland cancers very conspicuous as well as some transitional cancers which can show, in some cases, an homogeneous hyposignal. (authors). 15 refs., 14 figs.

  5. Pere de Moragues, mestre major de l 'obra de la seu de Tortosa

    Directory of Open Access Journals (Sweden)

    Almuni Balada, Maria Victòria

    2000-06-01

    Full Text Available The documented research, carried out during the last years in the Chapter Archive in Tortosa, has hallowed us to verify the presence in the town of some master craftsmen, specially stone-cutters, who are related with the works in the cathedral. Some of them had already been pointed out by canon Josep Matamoros in La Catedral de Tortosa. Others, however, had not been reported yet. That is the case of Pere de Moragues who was an imagery sculptor and goldsmith from Barcelona and whom we have discovered working as major master in the workshop of the Tortosa catedral in 1382-1383. From the very beginning our objective has always been to explain the conclusions of our research as a whole; nevertheless, the specific interest of some documents, which verify the presence of the above mentioned Pere Moragues directing the works in the cathedral of Tortosa, led us to publish them in advance. On the hand, the documents corresponding to the signature of Pere Moragues's contract as the major master on the works of the Gothic Catedral have been found in the notary registrations; on the other hand, some specific references have been taken from the books registering the work in the period 1382-1383 and which confirm his presence in the workshop. The documents related with Pere Moragues introduce new information and make us talk about two other stone-cutter masters, of whom we had very little reference. One of them is Antoni Guare, who had already been identified by Josep Matamoros as his signature was in the plant pan of die cathedral. The plan was found in the Chapter Archive in Tortosa and, up now, it has been dated by 1345. Our contribution delays the master's chronology since we have been able to notice a first presence of his in the works of the Cathedral of Tortosa in 1379, working as imagery maker; and later in 1382 as rival of Pere Moragues as major master in the workshop. The second stone-cutter master is Joan de Mayni. Joan de Mayni arrived in Tortosa

  6. Alternative Approach of Developing Optical Binary Adder Using Reversible Peres Gates

    Directory of Open Access Journals (Sweden)

    Dhoumendra Mandal

    2018-01-01

    Full Text Available All-optical devices will play a very significant and crucial role in the modern all-optical network by eliminating the bottleneck of opto-electro-opto- (O-E-O- conversion. Unfortunately, the conventional logic gates lose information at the output, and the states of the outputs cannot give any credible impressions of the states of the inputs. In this article, at first, the authors have proposed a method of designing an optical three-input-three-output reversible Peres gate. Authors have deployed polarization switching characteristic of Semiconductor Optical Amplifier (SOA for designing this circuit. The authors have also proposed a method of designing an optical reversible full adder, using two such Peres gates and subsequently a data recovery circuit which can recover the input data of the adder. The authors have chosen frequency encoded data for processing the operation. The proposed scheme has been verified by simulation results.

  7. High-resolution MRI using orbit surface coils for the evaluation of metastatic risk factors in 143 children with retinoblastoma. Part 1: MRI vs. histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Sirin, Selma; Schlamann, Marc; Schweiger, Bernd; Goericke, Sophia L. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Metz, Klaus A. [University Hospital Essen, Department of Pathology and Neuropathology, Essen (Germany); Bornfeld, Norbert; Holdt, Markus [University Hospital Essen, Department of Ophthalmology, Essen (Germany); Temming, Petra; Schuendeln, Michael M. [University Hospital Essen, Department of Pediatric Hematology and Oncology, Essen (Germany)

    2015-08-15

    A reliable detection of metastatic risk factors is important for children with retinoblastoma to choose the right therapeutic regimen. First studies using high-resolution magnetic resonance imaging (MRI) with orbit surface coils were promising. The aim of this study was therefore to evaluate the ability of high-resolution MRI to detect metastatic and especially advanced metastatic risk factors in a large group of children with retinoblastoma. One hundred forty-three consecutive children with retinoblastoma (148 enucleated eyes, 64 girls, 79 boys, mean age 19.7 ± 15.3) who received pretherapeutical high-resolution MRI with orbit surface coils on 1.5 T MR scanner systems between 2007 and 2012 and subsequent primary enucleation within 14 days were included in this retrospective study. Image analysis was performed by two neuroradiologists experienced in ocular imaging in consensus. Histopathology served as gold standard. Sensitivity/specificity for the detection of metastatic risk factors using high-resolution MRI with orbit surface coils were 60 %/88.7 % for postlaminar optic nerve infiltration, 65.5 %/95.6 % for choroidal invasion, 100 %/99.3 % for scleral invasion, and 100 %/100 % for peribulbar fat invasion, respectively. The results increased for the detection of advanced metastatic risk factors, 81.8 %/89.1 % for deep postlaminar optic nerve infiltration, 70.6 %/97.6 % for massive choroidal invasion. High-resolution MRI is clinically valuable for the detection of metastatic, especially of advanced metastatic risk factors in children with retinoblastoma. (orig.)

  8. Improved imaging of cochlear nerve hypoplasia using a 3-Tesla variable flip-angle turbo spin-echo sequence and a 7-cm surface coil.

    Science.gov (United States)

    Giesemann, Anja M; Raab, Peter; Lyutenski, Stefan; Dettmer, Sabine; Bültmann, Eva; Frömke, Cornelia; Lenarz, Thomas; Lanfermann, Heinrich; Goetz, Friedrich

    2014-03-01

    Magnetic resonance imaging of the temporal bone has an important role in decision making with regard to cochlea implantation, especially in children with cochlear nerve deficiency. The purpose of this study was to evaluate the usefulness of the combination of an advanced high-resolution T2-weighted sequence with a surface coil in a 3-Tesla magnetic resonance imaging scanner in cases of suspected cochlear nerve aplasia. Prospective study. Seven patients with cochlear nerve hypoplasia or aplasia were prospectively examined using a high-resolution three-dimensional variable flip-angle turbo spin-echo sequence using a surface coil, and the images were compared with the same sequence in standard resolution using a standard head coil. Three neuroradiologists evaluated the magnetic resonance images independently, rating the visibility of the nerves in diagnosing hypoplasia or aplasia. Eight ears in seven patients with hypoplasia or aplasia of the cochlear nerve were examined. The average age was 2.7 years (range, 9 months-5 years). Seven ears had accompanying malformations. The inter-rater reliability in diagnosing hypoplasia or aplasia was greater using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence (fixed-marginal kappa: 0.64) than with the same sequence in lower resolution (fixed-marginal kappa: 0.06). Examining cases of suspected cochlear nerve aplasia using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence in combination with a surface coil shows significant improvement over standard methods. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  9. Comparative study between body and surface coils in magnetic resonance mammography of silicone prosthesis; Estudo comparativo entre bobinas de corpo e superficie na mamografia por ressonancia magnetica de proteses de silicone

    Energy Technology Data Exchange (ETDEWEB)

    Scaranelo, Anabel Medeiros [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Diagnostico por Imagem]. E-mail: anabelms@uol.com.br

    2001-04-01

    Magnetic resonance imaging scans using predefined parameters were performed in patients with silicone breast implants. The same group of patients was submitted to magnetic resonance imaging scans using surface breast coils and body coils, and the results were compared. A total of 43 single-lumen silicone-gel breast implants in 24 patients were examined. The signal-to-noise ratio was greater for the breast coil than for the body coil. Radial folds were identified with equal resolution by both in almost 82% of the cases on the right side and 95% on the left side. In about 5% of the cases the folds were seen exclusively when the breast coil used. The linguine sign was almost equally with both methods. In just one case the linguine sign was observed only by using the breast coil. Identification of building or irregularity of contours were concordant using both techniques. We concluded that although magnetic resonance imaging quality is better using a dedicated coil, silicone breast implants can be assessed with the same diagnostic accuracy using a body coil. (author)

  10. Program of internal training of the ININ personnel participating in the PERE of the CLV (1998). I. Initial evaluation; Programa de capacitacion interna del personal del ININ participante en el PERE de la CLV (1998). I. Evaluacion inicial

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, G. [ININ, 52045 Ocoyoacac, EStado de Mexico (Mexico)

    1999-01-15

    According to the document 'Program of Internal Training of the Personnel of the ININ participant in the PERE of the CLV (1998)' presented to the National Center of Disasters Prevention, it was included an action of previous evaluation to courses and practices with the purpose of knowing the state of knowledge regarding those activities that have to carry out. In this report the results of the evaluation are presented. Six questionnaires were elaborated: 1. The PERE and its procedures. 2. Control of the radiological exposure of the response personnel. 3. Control of water and foods. 4. Communications system of the PERE. 5. Monitoring, classification and decontamination of having evacuated. 6. Specialized medical attention. (Author)

  11. Program of internal training of the ININ personnel participating in the PERE of the CLV (1998). I. Initial evaluation

    International Nuclear Information System (INIS)

    Suarez, G.

    1999-01-01

    According to the document 'Program of Internal Training of the Personnel of the ININ participant in the PERE of the CLV (1998)' presented to the National Center of Disasters Prevention, it was included an action of previous evaluation to courses and practices with the purpose of knowing the state of knowledge regarding those activities that have to carry out. In this report the results of the evaluation are presented. Six questionnaires were elaborated: 1. The PERE and its procedures. 2. Control of the radiological exposure of the response personnel. 3. Control of water and foods. 4. Communications system of the PERE. 5. Monitoring, classification and decontamination of having evacuated. 6. Specialized medical attention. (Author)

  12. Non-granulomatous prostatitis: MR appearance with an endorectal surface coil; Nichtgranulomatoese Prostatitis: Erscheinungsbild im MRT mit endorektaler Oberflaechenspule (``Endo-MRT``)

    Energy Technology Data Exchange (ETDEWEB)

    Szolar, D.H.M. [Magnetresonanztomographie-Zentrum, Univ. Graz (Austria); Ranner, G. [Magnetresonanztomographie-Zentrum, Univ. Graz (Austria); Preidler, K.W. [Magnetresonanztomographie-Zentrum, Univ. Graz (Austria); Lax, S. [Inst. fuer Pathologische Anatomie, Univ. Graz (Austria)

    1995-01-01

    Inflammatory conditions of the prostate are often idfficult to distinguish from early stages of prostate cancer with imaging techniques. The use of an endorectal surface coil in MRI of the prostate gland has been reported to provide superior resolution and better imaging of details than MRI with a body coil in the diagnosis of early prostate cancer. We report a 34-year-old patient with nonspecific non-granlomatous prostatitis in whom T{sub 2}-weighted endorectal surface coil magnetic resonance imaging (ESCMRI) showed a region of markedly decreased signal intensity in the periphery of the gland. The low signal intensity of the lesion, its sharp demarcation from the normal part of the peripheral zone of the prostate and the marked bulge of the surface contour without capsular breach of the organ were interpreted as evidence of a bioptically proven benign inflammatory condition. (orig.) [Deutsch] Die Unterscheidung entzuendlicher Prozesse von Fruehstadien maligner Neoplasien der Prostata mittels Magnetresonanztomographie bereitet immer wieder Schwierigkeiten. Die Anwendung einer Oberflaechenspule erlaubt durch hoehere Aufloesung eine exaktere Beurteilung der Prostatakapsel, was eine hoehere Treffsicherheit beim Nachweis moeglicher organueberschreitender Infiltrationen bedeutet. Wir praesentieren den Fall eines 34jaehrigen Mannes mit unspezifischer, nichtgranulomatoeser Prostatitis, bei dem das MR-Tomogramm mit endorektal plazierter Oberflaechenspule (Endo-MRT) in der Peripherzone ein Areal deutlich herabgesetzter Signalintensitaet auf T{sub 2}-gewichteten Aufnahmen zeigte. Die scharfe Begrenzung der ausgedehnten signalarmen Laesion gegenueber dem nichtbefallenen Anteil der Peripherzone beim im Endo-MRT identifizierbarer intakter Kapsel liess ein organueberschreitendes Malignom ausschliessen und bestaetigte durch histologische Aufarbeitung der Bioptate den Endo-MRT-Verdachtsbefund einer Prostatitis. (orig.)

  13. Pere de Moragues, mestre major de l 'obra de la seu de Tortosa

    OpenAIRE

    Almuni Balada, Maria Victòria

    2000-01-01

    The documented research, carried out during the last years in the Chapter Archive in Tortosa, has hallowed us to verify the presence in the town of some master craftsmen, specially stone-cutters, who are related with the works in the cathedral. Some of them had already been pointed out by canon Josep Matamoros in La Catedral de Tortosa. Others, however, had not been reported yet. That is the case of Pere de Moragues who was an imagery sculptor and goldsmith from Barcelona and whom we have dis...

  14. Noiseless method for checking the Peres separability criterion by local operations and classical communication

    International Nuclear Information System (INIS)

    Bai Yankui; Li Shushen; Zheng Houzhi

    2005-01-01

    We present a method for checking the Peres separability criterion in an arbitrary bipartite quantum state ρ AB within local operations and classical communication scenario. The method does not require noise operation which is needed in making the partial transposition map physically implementable. The main task for the two observers, Alice and Bob, is to measure some specific functions of the partial transposed matrix. With these functions, they can determine the eigenvalues of ρ AB T B , among which the minimum serves as an entanglement witness

  15. La casa i l'obrador de Pere Sanglada, mestre d'imatges de Barcelona (+1408)

    OpenAIRE

    Batlle i Gallart, Carme

    1993-01-01

    La publicación del inventario de Pere Sanglada no sólo nos permite fijar con exactitud la fecha de su muerte, el marzo de 1408, sino que además nos informa de la situación familiar del escultor y de las características y contenido de la vivienda. El notario hace una descripción pormenorizada de su taller, donde aparecen esculturas, algunas sin terminar, dibujos preparatorios y las más variadas herramientas, aptas para trabajar la piedra, la madera y los metales. Sorprende gratamente que se de...

  16. Optimizing T2-weighted magnetic resonance sequences for surface coil microimaging of the eye with regard to lid, eyeball and head moving artifacts.

    Science.gov (United States)

    Obata, Takayuki; Uemura, Koji; Nonaka, Hiroi; Tamura, Mitsuru; Tanada, Shuji; Ikehira, Hiroo

    2006-01-01

    To acquire high-resolution magnetic resonance (MR) images, we developed a new blinking artifact reduced pulse (BARP) sequence with a surface coil specialized for microscopic imaging (47 mm in diameter). To reduce eye movement, we ascertained that the subjects' eyes were kept open and fixated to the target in the 1.5-T MR gantry. To reduce motion artifacts from blinking, we inserted rest periods for blinking (1.5 s within every 5 s) during MR scanning (T2-weighted fast spin echo; repetition time, 5 s; echo time, 100 ms; echo train, 11; matrix, 256 x 128; field of view, 5 cm; 1-mm thickness x 30 slices). Three scans (100 s x 3) were performed for each normal subject, and they were added together after automatic adjustment for location to reduce quality loss caused by head motion. T2-weighted MR images were acquired with a high resolution and a high signal-to-noise ratio. Motion artifacts were reduced with BARP, as compared with those with random blinking. Intraocular structures such as the iris and ciliary muscles were clearly visualized. Because the whole eye can be covered with a 1-mm thickness by this method, three-dimensional maps can easily be generated from the obtained images. The application of BARP with a surface coil of the human eye might become a useful and widely adopted procedure for MR microimaging.

  17. Dependence of B1+ and B1- Field Patterns of Surface Coils on the Electrical Properties of the Sample and the MR Operating Frequency.

    Science.gov (United States)

    Vaidya, Manushka V; Collins, Christopher M; Sodickson, Daniel K; Brown, Ryan; Wiggins, Graham C; Lattanzi, Riccardo

    2016-02-01

    In high field MRI, the spatial distribution of the radiofrequency magnetic ( B 1 ) field is usually affected by the presence of the sample. For hardware design and to aid interpretation of experimental results, it is important both to anticipate and to accurately simulate the behavior of these fields. Fields generated by a radiofrequency surface coil were simulated using dyadic Green's functions, or experimentally measured over a range of frequencies inside an object whose electrical properties were varied to illustrate a variety of transmit [Formula: see text] and receive [Formula: see text] field patterns. In this work, we examine how changes in polarization of the field and interference of propagating waves in an object can affect the B 1 spatial distribution. Results are explained conceptually using Maxwell's equations and intuitive illustrations. We demonstrate that the electrical conductivity alters the spatial distribution of distinct polarized components of the field, causing "twisted" transmit and receive field patterns, and asymmetries between [Formula: see text] and [Formula: see text]. Additionally, interference patterns due to wavelength effects are observed at high field in samples with high relative permittivity and near-zero conductivity, but are not present in lossy samples due to the attenuation of propagating EM fields. This work provides a conceptual framework for understanding B 1 spatial distributions for surface coils and can provide guidance for RF engineers.

  18. Eye imaging with a 3.0-T MRI using a surface coil - a study on volunteers and initial patients with uveal melanoma

    International Nuclear Information System (INIS)

    Lemke, Arne-Joern; Hengst, Susanne Anja; Kazi, Iris; Felix, Roland; Alai-Omid, Minouche

    2006-01-01

    MRI of uveal melanoma using 1.5-T technology and surface coils has developed into a standard procedure. The purpose of the study was to evaluate the feasibility of 3.0-T technology in eye imaging. To optimize the MRI sequences for clinical eye imaging with 3.0-T, six healthy volunteers were conducted using a 4.0-cm surface coil. Evaluation criteria were the signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR) and image quality. A further six patients with uveal melanoma were examined with 1.5- and 3.0-T under retrobulbar anesthesia. During 3.0-T examinations of volunteers, eye movements caused significant artifacts. On the contrary, excellent imaging quality was reached in examinations of patients under retrobulbar anesthesia at 3.0 T. Subjective assessment showed no significant difference between 1.5 and 3.0 T in patients. Due to the increased SNR, the 3.0-T technique has the potential to improve eye imaging, but the higher susceptibility to motion artifacts limits the clinical use of this technique to patients receiving retrobulbar anesthesia. (orig.)

  19. Quantum chaos for nonstandard symmetry classes in the Feingold-Peres model of coupled tops.

    Science.gov (United States)

    Fan, Yiyun; Gnutzmann, Sven; Liang, Yuqi

    2017-12-01

    We consider two coupled quantum tops with angular momentum vectors L and M. The coupling Hamiltonian defines the Feingold-Peres model, which is a known paradigm of quantum chaos. We show that this model has a nonstandard symmetry with respect to the Altland-Zirnbauer tenfold symmetry classification of quantum systems, which extends the well-known threefold way of Wigner and Dyson (referred to as "standard" symmetry classes here). We identify the nonstandard symmetry classes BDI_{0} (chiral orthogonal class with no zero modes), BDI_{1} (chiral orthogonal class with one zero mode), and CI (antichiral orthogonal class) as well as the standard symmetry class AI (orthogonal class). We numerically analyze the specific spectral quantum signatures of chaos related to the nonstandard symmetries. In the microscopic density of states and in the distribution of the lowest positive energy eigenvalue, we show that the Feingold-Peres model follows the predictions of the Gaussian ensembles of random-matrix theory in the appropriate symmetry class if the corresponding classical dynamics is chaotic. In a crossover to mixed and near-integrable classical dynamics, we show that these signatures disappear or strongly change.

  20. KEANEKARAGAMAN SPESIES ULAR DI DESA PERING, KECAMATAN BLAHBATUH, KABUPATEN GIANYAR, BALI

    Directory of Open Access Journals (Sweden)

    I GEDE MADE ARIUS HADY BUDIADA

    2017-06-01

    Full Text Available Snakes are cold-blooded reptiles belong to the Order Squamata, Suborder Serpentes. Snakes often found in lowlands, highlands, trees, soil, water and swamps. People in the Pering village especially in Banjar Perang Sada have less knowledge about venomous and non-venomous snakes. Therefore, it is important to investigate the diversity of snakes in the Pering village, Blahbatuh, Gianyar. This study was conducted on 28 January – 4 February 2015. Data collection was performed by direct observation along the potential snake habitats in two plots rice field near residential area and near the Pura Beji. Data collection was performed during night time from at 7:00 to 11:00 PM with sampling focused on Banjar Perang Sada. Individual snake found was cought and identified in situ. This research found 9 species of snakes namely, Ahaetulla prasina, Boiga cynodon, Dendrelaphis pictus, Pareas carinatus, Ptyas korros, Rhabdophis chrysargos, Xenochrophis piscator, Bungarus fasciatus, and Trimeresurus insularis, the most commonly found was Dendrelaphis pictus.

  1. Vanemuise teatri juurdeehituse kutsutud arhitektuurikonkurss = Invitational architecture competition for the addition to the Vanemuine theatre / Peeter Pere

    Index Scriptorium Estoniae

    Pere, Peeter, 1957-

    2009-01-01

    Arhitektuurikonkursi žürii liige Peeter Pere võistluse eesmärgist, konkursil 1. preemia pälvinud Jüri Okase ja Marika Lõokese (Okas & Lõoke) võistlustööst ja konkursil osalenud arhitektuuribüroode Kolm Pluss Üks, Kavakava ja Lunge & Ko võistlustöödest

  2. Uued CO₂ kasukad vanadele majadele / Elari Udam ; intervjueerinud Margit Mutso ; kommenteerinud Peeter Pere, Oliver Orro, Jaak Huimerind

    Index Scriptorium Estoniae

    Udam, Elari, 1968-

    2011-01-01

    Vabade CO₂ kvootide müügist laekunud raha eest renoveeritakse energiatõhusaks 480 Eesti hoonet. Projekti juhib Riigi Kinnisvara AS. Teemat selgitab RKASi juhatuse liige ja haldusdirektor Elari Udam, kommenteerivad Eesti Arhitektide Liidu esimees Peeter Pere, aseesimees Jaak Huimerind ja arhitektuuriajaloolane Oliver Orro

  3. Comparison of (31)P saturation and inversion magnetization transfer in human liver and skeletal muscle using a clinical MR system and surface coils.

    Science.gov (United States)

    Buehler, Tania; Kreis, Roland; Boesch, Chris

    2015-02-01

    (31)P MRS magnetization transfer ((31)P-MT) experiments allow the estimation of exchange rates of biochemical reactions, such as the creatine kinase equilibrium and adenosine triphosphate (ATP) synthesis. Although various (31)P-MT methods have been successfully used on isolated organs or animals, their application on humans in clinical scanners poses specific challenges. This study compared two major (31)P-MT methods on a clinical MR system using heteronuclear surface coils. Although saturation transfer (ST) is the most commonly used (31)P-MT method, sequences such as inversion transfer (IT) with short pulses might be better suited for the specific hardware and software limitations of a clinical scanner. In addition, small NMR-undetectable metabolite pools can transfer MT to NMR-visible pools during long saturation pulses, which is prevented with short pulses. (31)P-MT sequences were adapted for limited pulse length, for heteronuclear transmit-receive surface coils with inhomogeneous B1 , for the need for volume selection and for the inherently low signal-to-noise ratio (SNR) on a clinical 3-T MR system. The ST and IT sequences were applied to skeletal muscle and liver in 10 healthy volunteers. Monte-Carlo simulations were used to evaluate the behavior of the IT measurements with increasing imperfections. In skeletal muscle of the thigh, ATP synthesis resulted in forward reaction constants (k) of 0.074 ± 0.022 s(-1) (ST) and 0.137 ± 0.042 s(-1) (IT), whereas the creatine kinase reaction yielded 0.459 ± 0.089 s(-1) (IT). In the liver, ATP synthesis resulted in k = 0.267 ± 0.106 s(-1) (ST), whereas the IT experiment yielded no consistent results. ST results were close to literature values; however, the IT results were either much larger than the corresponding ST values and/or were widely scattered. To summarize, ST and IT experiments can both be implemented on a clinical body scanner with heteronuclear transmit-receive surface coils; however, ST results are

  4. Coil supporting device in a nuclear fusion device

    International Nuclear Information System (INIS)

    Takano, Hirohisa; Sasaki, Katsutoki.

    1976-01-01

    Object: To slide a vacuum vessel in the nuclear fusion device and a coil within the vacuum vessel and to mount the coil within the vacuum vessel in a manner that it may not be moved by an electromagnetic force, thereby preventing stress from being produced in the coil. Structure: A coil supporting plate mounted at upper and lower parts prevents damage to an insulation of the coil, said coil being held in a U-shaped groove, and can be moved integral with the coil by the action of a roller bearing with a plurality of needle-like rollers arranged in parallel. The coil supporting plate has a plurality of projections disposed on the lower surface thereof, and flat springs are placed in the projections one over another so that the spring action exerted in the lower plate causes the coil to be resiliently bias in a direction of an electromagnetic force applied thereto and to support the coil. (Yoshino, Y.)

  5. From Cosmopolitanism to Planetary Conviviality: Suneeta Peres da Costa and Michelle de Kretser

    Directory of Open Access Journals (Sweden)

    Alejandra Moreno Álvarez

    2017-01-01

    Full Text Available Veronica Brady, vigorous supporter of Aboriginal causes and deeply concerned with social-injustice issues, underlined that Anglo-Australians were to be excommunicated from the land until they would come to terms with it and its first peoples (in Jones 1997. Nearly twenty years after this statement was postulated, it is my purpose in this paper to look at the land from an Anglo-Australian and non-Indigenous Australian perspective in order to assess if Australian contemporary society has moved beyond what Brady considered a “super ego status” and reconciled to the presence not only of its Indigenous, but also its non-Indigenous others. To do so I will exemplify novels which are part of and influenced by the matrix of relations and social forces in which non-indigenous Australian writers are situated on, including Suneeta Peres da Costa’s Homework (1999 and Michelle de Kretser’s Questions of Travel (2013.

  6. Conception of Brownian coil

    OpenAIRE

    Zhang, Jiayuan

    2018-01-01

    This article proposes a conception of Brownian coil. Brownian coil is a tiny coil with the same size of pollen. Once immersed into designed magnetic field and liquid, the coil will be moved and deformed macroscopically, due to the microscopic thermodynamic molecular collisions. Such deformation and movement will change the magnetic flux through the coil, by which an ElectroMotive Force (EMF) is produced. In this work, Brownian heat exchanger and Brownian generator are further designed to tran...

  7. Fabrication of the KSTAR toroidal field coil structure

    International Nuclear Information System (INIS)

    Choi, C.H.; Sa, J.W.; Park, H.K.; Hong, K.H.; Shin, H.; Kim, H.T.; Bak, J.S.; Lee, G.S.; Kwak, J.H.; Moon, H.G.; Yoon, H.H.; Lee, J.W.; Lee, S.K.; Song, J.Y.; Nam, K.M.; Byun, S.E.; Kim, H.C.; Ha, E.T.; Ahn, H.J.; Kim, D.S.; Lee, J.S.; Park, K.H.; Hong, C.D.

    2005-01-01

    The KSTAR toroidal field (TF) coil structure is under fabrication upon completion of engineering design and prototype construction. The prototype TF coil structure has been fabricated within allowable tolerances. Encasing of the prototype TF coil (TF00) in the prototype structure has been carried out through major processes involving a coil encasing, an enclosing weld, a vacuum pressure impregnation, and an outer surface machining. During the enclosing weld of the TF00 coil structure, we have measured temperatures and stresses on the coil surface. Assembly test had been performed with the TF00 coil structure. We have chosen Type 316LN as material of the TF coil structure. We used the narrow-gap TIG welding method. Doosan Heavy Industries and Construction Company (DHI) will complete the fabrication of the TF coil structure in Feb. 2006. (author)

  8. Absolute quantitation of phosphorus metabolites in the cerebral cortex of the newborn human infant and in the forearm muscles of young adults using a double-tuned surface coil

    Science.gov (United States)

    Cady, Ernest B.

    The application of a double-tuned surface coil with strong coupling for both 31P and 1H to the in vivo measurement of metabolite concentrations by NMR spectroscopy is demonstrated. It is shown that sample loading, although important for a coil tuned to a single frequency, does not necessarily have a significant effect on absolute quantitation results if the coil is strongly coupled to the sample for both nuclei. For the coil used in the present study, the spectrometer calibration coefficient is almost independent of loading and the 1H and 31P flip angles at the coil center produced by fixed length pulses could be arranged to be nearly equal over a range of loading conditions. In seven normal infants, of gestational plus postnatal age 35 to 37 weeks, the cerebral cortex nucleotide triphosphate concentration was 3.7 ± 0.6 m M/liter wet (mean ± SD). Metabolite concentrations were low in the cerebral cortex of a severely birth asphyxiated infant. The adenosine triphosphate concentration in the resting, fresh forearm muscles of six young adults was 6.3 ± 0.8 m M/liter wet.

  9. Tulumaksuseaduse muudatusest võidab tugev ja töökas pere / Jaanus Männik

    Index Scriptorium Estoniae

    Männik, Jaanus, 1951-

    2005-01-01

    Tulumaksuseaduse muudatusest, mis kehtestab lisatulumaksuvabastuse maksuvaba miinimumi ulatuses alates pere teisest lapsest 1. jaan. 2006. Sama ka Nädaline 28. juuni 2005, lk. 4 ; Hiiu Leht 5. juuli 2005, lk. 2 ; Koit 7. juuli 2005, lk. 6 ; Vali Uudised 6. juuli 2005, lk. 2 ; Pärnu Postimees 8. juuli 2005, lk. 11 ; Põhjarannik 8. juuli 2005, lk. 2 ; Severnoje poberezje 8. juuli 2005, lk. 2

  10. Water cooling coil

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S; Ito, Y; Kazawa, Y

    1975-02-05

    Object: To provide a water cooling coil in a toroidal nuclear fusion device, in which coil is formed into a small-size in section so as not to increase dimensions, weight or the like of machineries including the coil. Structure: A conductor arranged as an outermost layer of a multiple-wind water cooling coil comprises a hollow conductor, which is directly cooled by fluid, and as a consequence, a solid conductor disposed interiorly thereof is cooled indirectly.

  11. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  12. Appearance of choroidal melanoma on high resolution MRI using 1.5 T and a dedicated surface coil in 200 consecutive patients

    International Nuclear Information System (INIS)

    Lemke, A.J.; Hosten, N.; Frenzel, D.; Richter, M.; Felix, R.; Bornfeld, N.; Bechrakis, N.E.

    1998-01-01

    Purpose: Choroidal melanomas usually present a characteristic appearance in MRI. Differing characteristics can cause problems in differential diagnosis between melanomas and other masses in the globe. The purpose of this study was to evaluate the appearance of choroidal melanomas with MRI in a large consecutive patient group. Methods: In a prospective study, 200 patients with choroidal melanomas were investigated with MRI using a 1.5 T scanner and a 5 cm surface coil. Both quantitative and qualitative evaluation of the resulting images was performed. Results: 78.5% of the melanomas presented with homogeneous signal intensities within the tumor due to a homogeneous pigmentation whereas 21.5% of the melanomas demonstrated a mixed pigmentation. Signal intensities of the homogeneous melanomas in the plain T 1 -WI were moderately or markedly hyperintense compared to the vitreous in 29.3% and moderately or markedly hypointense in the T 2 -WI in 37.1%. An accompanying retinal detachment was found in 65.5% and an extraocular growth in 7.0%. Conclusions: In 10% to 37% we observed the typical well known MR appearance, including homogenous high signal in the T 1 -WI and low signals in the T 2 -WI. For further differentiation, morphological criteria (e.g. shape, size, and position) were used, which are also discussed. (orig.) [de

  13. Quantum steering of multimode Gaussian states by Gaussian measurements: monogamy relations and the Peres conjecture

    International Nuclear Information System (INIS)

    Ji, Se-Wan; Nha, Hyunchul; Kim, M S

    2015-01-01

    It is a topic of fundamental and practical importance how a quantum correlated state can be reliably distributed through a noisy channel for quantum information processing. The concept of quantum steering recently defined in a rigorous manner is relevant to study it under certain circumstances and here we address quantum steerability of Gaussian states to this aim. In particular, we attempt to reformulate the criterion for Gaussian steering in terms of local and global purities and show that it is sufficient and necessary for the case of steering a 1-mode system by an N-mode system. It subsequently enables us to reinforce a strong monogamy relation under which only one party can steer a local system of 1-mode. Moreover, we show that only a negative partial-transpose state can manifest quantum steerability by Gaussian measurements in relation to the Peres conjecture. We also discuss our formulation for the case of distributing a two-mode squeezed state via one-way quantum channels making dissipation and amplification effects, respectively. Finally, we extend our approach to include non-Gaussian measurements, more precisely, all orders of higher-order squeezing measurements, and find that this broad set of non-Gaussian measurements is not useful to demonstrate steering for Gaussian states beyond Gaussian measurements. (paper)

  14. Biomaterials Made from Coiled-Coil Peptides.

    Science.gov (United States)

    Conticello, Vincent; Hughes, Spencer; Modlin, Charles

    The development of biomaterials designed for specific applications is an important objective in personalized medicine. While the breadth and prominence of biomaterials have increased exponentially over the past decades, critical challenges remain to be addressed, particularly in the development of biomaterials that exhibit highly specific functions. These functional properties are often encoded within the molecular structure of the component molecules. Proteins, as a consequence of their structural specificity, represent useful substrates for the construction of functional biomaterials through rational design. This chapter provides an in-depth survey of biomaterials constructed from coiled-coils, one of the best-understood protein structural motifs. We discuss the utility of this structurally diverse and functionally tunable class of proteins for the creation of novel biomaterials. This discussion illustrates the progress that has been made in the development of coiled-coil biomaterials by showcasing studies that bridge the gap between the academic science and potential technological impact.

  15. Superconducting magnetic coil

    Science.gov (United States)

    Aized, Dawood; Schwall, Robert E.

    1996-06-11

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  16. Cooling and dehumidifying coils

    International Nuclear Information System (INIS)

    Murthy, M.V.K.

    1988-01-01

    The operating features of cooling and dehumidifying coils and their constructional details are discussed. The heat transfer relations as applicable to the boiling refrigerant and a single phase fluid are presented. Methods of accounting for the effect of moisture condensation on the air side heat transfer coefficient and the fin effectiveness are explained. The logic flow necessary to analyze direct expansion coils and chilled water coils is discussed

  17. The JET divertor coil

    International Nuclear Information System (INIS)

    Last, J.R.; Froger, C.; Sborchia, C.

    1989-01-01

    The divertor coil is mounted inside the Jet vacuum vessel and is able to carry 1 MA turns. It is of conventional construction - water cooled copper, epoxy glass insulation -and is contained in a thin stainless steel case. The coil has to be assembled, insulated and encased inside the Jet vacuum vessel. A description of the coil is given, together with technical information (including mechanical effects on the vacuum vessel), an outline of the manufacture process and a time schedule. (author)

  18. High resolution MR imaging of the anal sphincter using an intravaginal surface coil; Hochaufloesende Magnetresonanztomographie des Analsphinkters mit einer intravaginalen Oberflaechenspule

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Schimpfle, M. [Radiologische Klinik, Abt. fuer Radiologische Diagnostik, Tuebingen Univ. (Germany); Franz, H. [Frauenklinik, Tuebingen Univ. (Germany); Lobinger, B. [Radiologische Klinik, Abt. fuer Radiologische Diagnostik, Tuebingen Univ. (Germany); Claussen, C.D. [Radiologische Klinik, Abt. fuer Radiologische Diagnostik, Tuebingen Univ. (Germany)

    1995-06-01

    MR imaging was performed using a 1.0 T unit. In 10 females (6 nullipara, one primipara without and three primipara with postpartum faecal incontinence) a surface coil, originally designed for endorectal use, was placed into the vagina. Transverse oblique T{sub 1}-weighted spin echo and double echo turbo spin echo sequences with T{sub 2}- and proton density-weighting were acquired parallel to the puborectal, rectococcygeal and anorectal planes. Three readers analysed the images in consensus. The anatomic structures of the external and internal sphincter as well as the mucosa were differentiated in all cases with a good contrast. The best results were yielded by the proton density weighting. In one case of faecal incontinence a sphincter defect after repair of a complete rupture of the anal sphincter was shown. In another case irregularities in the structure of the external sphincter and perineum were visualised. (orig./MG) [Deutsch] Die Magnetresonanztomographie (MRT) wurde an einem 1,0-Tesla-Geraet durchgefuehrt. Bei 10 Frauen (6 Nulliparae, eine Primipara ohne und drei Primiparae mit postpartaler Stuhlinkontinenz) wurde eine Oberflaechenspule, die urspruenglich zur endorektalen Anwendung konzipiert war, intravaginal eingefuehrt. Es wurden T{sub 1}-gewichtete Spin-Echo-Sequenzen sowie Doppel-Echo-Turbo-Spin-Echo-Sequenzen mit T{sub 2}- und Protonendichtegewichtung parallel zur puborektalen, rektokokzygealen und anorektalen Ebene akquiriert. Drei Auswerter analysierten die Aufnahmen im Konsensmodus. Die anatomischen Strukturen des Musculus sphincter ani externus und internus sowie die Mukosa konnten in allen Faellen gut differenziert werden. Das beste Ergebnis wurde mit der Protonendichte-Gewichtung erzielt. In einem Fall von Stuhlinkontinenz zeigte sich ein kombinierter Defekt des M. sphincter ani internus und externus nach Naht eines Dammrisses III. Grades. In einem weiteren Fall waren Irregularitaeten im Perineum und externen Sphinkteranteil darzustellen. (orig./MG)

  19. Salecker-Wigner-Peres clock, Feynman paths, and a tunneling time that should not exist

    Science.gov (United States)

    Sokolovski, D.

    2017-08-01

    The Salecker-Wigner-Peres (SWP) clock is often used to determine the duration a quantum particle is supposed to spend in a specified region of space Ω . By construction, the result is a real positive number, and the method seems to avoid the difficulty of introducing complex time parameters, which arises in the Feynman paths approach. However, it tells little about the particle's motion. We investigate this matter further, and show that the SWP clock, like any other Larmor clock, correlates the rotation of its angular momentum with the durations τ , which the Feynman paths spend in Ω , thereby destroying interference between different durations. An inaccurate weakly coupled clock leaves the interference almost intact, and the need to resolve the resulting "which way?" problem is one of the main difficulties at the center of the "tunnelling time" controversy. In the absence of a probability distribution for the values of τ , the SWP results are expressed in terms of moduli of the "complex times," given by the weighted sums of the corresponding probability amplitudes. It is shown that overinterpretation of these results, by treating the SWP times as physical time intervals, leads to paradoxes and should be avoided. We also analyze various settings of the SWP clock, different calibration procedures, and the relation between the SWP results and the quantum dwell time. The cases of stationary tunneling and tunnel ionization are considered in some detail. Although our detailed analysis addresses only one particular definition of the duration of a tunneling process, it also points towards the impossibility of uniting various time parameters, which may occur in quantum theory, within the concept of a single tunnelling time.

  20. Intelligent shell feedback control in EXTRAP T2R reversed field pinch with partial coverage of the toroidal surface by a discrete active coil array

    Science.gov (United States)

    Yadikin, D.; Brunsell, P. R.; Drake, J. R.

    2006-01-01

    An active feedback system is required for long pulse operation of the reversed field pinch (RFP) device to suppress resistive wall modes (RWMs). A general feature of a feedback system using a discrete active coil array is a coupling effect which arises when a set of side band modes determined by the number of active coils is produced. Recent results obtained on the EXTRAP T2R RFP demonstrated the suppression of independent m = 1 RWMs using an active feedback system with a two-dimensional array of discrete active coils in the poloidal and toroidal directions. One of the feedback algorithms used is the intelligent shell feedback scheme. Active feedback systems having different number of active coils in the poloidal (Mc) and toroidal (Nc) directions (Mc × Nc = 2 × 32 and Mc × Nc = 4 × 16) are studied. Different side band effects are seen for these configurations. A significant prolongation of the plasma discharge is achieved for the intelligent shell feedback scheme using the 2 × 32 active coil configuration. This is attributed to the side band sets including only one of the dominant unstable RWMs and avoiding coupling to resonant modes. Analog proportional-integral-derivative controllers are used in the feedback system. Regimes with different values of the proportional gain are studied. The requirement of the proportional-integral control for low proportional gain and proportional-derivative control for high proportional gain is seen in the experiments.

  1. Active internal corrector coils

    International Nuclear Information System (INIS)

    Thompson, P.A.; Cottingham, J.; Dahl, P.

    1986-01-01

    Trim or corrector coils to correct main magnet field errors and provide higher multipole fields for beam optics purposes are a standard feature of superconducting magnet accelerator systems. This paper describes some of the design and construction features of powered internal trim coils and a sampling of the test results obtained

  2. Molecular basis of coiled-coil oligomerization-state specificity.

    Science.gov (United States)

    Ciani, Barbara; Bjelic, Saša; Honnappa, Srinivas; Jawhari, Hatim; Jaussi, Rolf; Payapilly, Aishwarya; Jowitt, Thomas; Steinmetz, Michel O; Kammerer, Richard A

    2010-11-16

    Coiled coils are extensively and successfully used nowadays to rationally design multistranded structures for applications, including basic research, biotechnology, nanotechnology, materials science, and medicine. The wide range of applications as well as the important functions these structures play in almost all biological processes highlight the need for a detailed understanding of the factors that control coiled-coil folding and oligomerization. Here, we address the important and unresolved question why the presence of particular oligomerization-state determinants within a coiled coil does frequently not correlate with its topology. We found an unexpected, general link between coiled-coil oligomerization-state specificity and trigger sequences, elements that are indispensable for coiled-coil formation. By using the archetype coiled-coil domain of the yeast transcriptional activator GCN4 as a model system, we show that well-established trimer-specific oligomerization-state determinants switch the peptide's topology from a dimer to a trimer only when inserted into the trigger sequence. We successfully confirmed our results in two other, unrelated coiled-coil dimers, ATF1 and cortexillin-1. We furthermore show that multiple topology determinants can coexist in the same trigger sequence, revealing a delicate balance of the resulting oligomerization state by position-dependent forces. Our experimental results should significantly improve the prediction of the oligomerization state of coiled coils. They therefore should have major implications for the rational design of coiled coils and consequently many applications using these popular oligomerization domains.

  3. Exploring the conserved water site and hydration of a coiled-coil trimerisation motif: a MD simulation study.

    Science.gov (United States)

    Dolenc, Jozica; Baron, Riccardo; Missimer, John H; Steinmetz, Michel O; van Gunsteren, Wilfred F

    2008-07-21

    The solvent structure and dynamics around ccbeta-p, a 17-residue peptide that forms a parallel three-stranded alpha-helical coiled coil in solution, was analysed through 10 ns explicit solvent molecular dynamics (MD) simulations at 278 and 330 K. Comparison with two corresponding simulations of the monomeric form of ccbeta-p was used to investigate the changes of hydration upon coiled-coil formation. Pronounced peaks in the solvent density distribution between residues Arg8 and Glu13 of neighbouring helices show the presence of water bridges between the helices of the ccbeta-p trimer; this is in agreement with the water sites observed in X-ray crystallography experiments. Interestingly, this water site is structurally conserved in many three-stranded coiled coils and, together with the Arg and Glu residues, forms part of a motif that determines three-stranded coiled-coil formation. Our findings show that little direct correlation exists between the solvent density distribution and the temporal ordering of water around the trimeric coiled coil. The MD-calculated effective residence times of up to 40 ps show rapid exchange of surface water molecules with the bulk phase, and indicate that the solvent distribution around biomolecules requires interpretation in terms of continuous density distributions rather than in terms of discrete molecules of water. Together, our study contributes to understanding the principles of three-stranded coiled-coil formation.

  4. The value of magnetic resonance imaging in target volume delineation of base of tongue tumours - A study using flexible surface coils

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Merina [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Schmidt, Maria [Cancer Research UK Clinical Magnetic Resonance Group, Royal Marsden NHS Foundation Trust, Surrey (United Kingdom); Sohaib, Aslam [Department of Radiology, Royal Marsden NHS Foundation Trust, London (United Kingdom); Kong, Christine; Burke, Kevin [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Richardson, Cheryl; Usher, Marianne [Cancer Research UK Clinical Magnetic Resonance Group, Royal Marsden NHS Foundation Trust, Surrey (United Kingdom); Brennan, Sinead [Department of Radiotherapy, St. James' s Hospital, Dublin (Ireland); Riddell, Angela [Department of Radiology, Royal Marsden NHS Foundation Trust, London (United Kingdom); Davies, Mark; Newbold, Kate [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Harrington, Kevin J; Nutting, Christopher M [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom)

    2010-02-15

    Introduction: Magnetic resonance imaging (MRI) provides superior diagnostic accuracy over computed tomography (CT) in oropharyngeal tumours. Precise delineation of the gross tumour volume (GTV) is mandatory in radiotherapy planning when a GTV boost is required. CT volume definition in this regard is poor. We studied the feasibility of using flexible surface (flex-L) coils to obtain MR images for MR-CT fusion to assess the benefit of MRI over CT alone in planning base of tongue tumours. Methods: Eight patients underwent CT and MRI radiotherapy planning scans with an immobilisation device. Distortion-corrected T1-weighted post-contrast MR scans were fused to contrast-enhanced planning CT scans. GTV, clinical target and planning target volumes (CTV, PTV) and organs at risk (OAR) were delineated on CT, then on MRI with blinding to the CT images. The volumetric and spatial differences between MRI and CT volumes for GTV, CTV, PTV and OAR were compared. MR image distortions due to field inhomogeneity and non-linear gradients were corrected and the need for such correction was evaluated. Results: The mean primary GTV was larger on MRI (22.2 vs. 9.5 cm{sup 3}, p = 0.05) than CT. The mean primary and nodal GTV (i.e. BOT and macroscopic nodes) was significantly larger on MRI (27.2 vs. 14.4 cm{sup 3}, p = 0.05). The volume overlap index (VOI) between MRI and CT for the primary was 0.34 suggesting that MRI depicts parts of the primary tumour not detected by CT. There was no significant difference in volume delineation between MR and CT for CTV, PTV, nodal CTV and nodal PTV. MRI volumes for brainstem and spinal cord were significantly smaller due to improved organ definition (p = 0.002). Susceptibility and gradient-related distortions were not found to be clinically significant. Conclusion: MRI improves the definition of tongue base tumours and neurological structures. The use of MRI is recommended for GTV dose-escalation techniques to provide precise depiction of GTV and

  5. The value of magnetic resonance imaging in target volume delineation of base of tongue tumours - A study using flexible surface coils

    International Nuclear Information System (INIS)

    Ahmed, Merina; Schmidt, Maria; Sohaib, Aslam; Kong, Christine; Burke, Kevin; Richardson, Cheryl; Usher, Marianne; Brennan, Sinead; Riddell, Angela; Davies, Mark; Newbold, Kate; Harrington, Kevin J.; Nutting, Christopher M.

    2010-01-01

    Introduction: Magnetic resonance imaging (MRI) provides superior diagnostic accuracy over computed tomography (CT) in oropharyngeal tumours. Precise delineation of the gross tumour volume (GTV) is mandatory in radiotherapy planning when a GTV boost is required. CT volume definition in this regard is poor. We studied the feasibility of using flexible surface (flex-L) coils to obtain MR images for MR-CT fusion to assess the benefit of MRI over CT alone in planning base of tongue tumours. Methods: Eight patients underwent CT and MRI radiotherapy planning scans with an immobilisation device. Distortion-corrected T1-weighted post-contrast MR scans were fused to contrast-enhanced planning CT scans. GTV, clinical target and planning target volumes (CTV, PTV) and organs at risk (OAR) were delineated on CT, then on MRI with blinding to the CT images. The volumetric and spatial differences between MRI and CT volumes for GTV, CTV, PTV and OAR were compared. MR image distortions due to field inhomogeneity and non-linear gradients were corrected and the need for such correction was evaluated. Results: The mean primary GTV was larger on MRI (22.2 vs. 9.5 cm 3 , p = 0.05) than CT. The mean primary and nodal GTV (i.e. BOT and macroscopic nodes) was significantly larger on MRI (27.2 vs. 14.4 cm 3 , p = 0.05). The volume overlap index (VOI) between MRI and CT for the primary was 0.34 suggesting that MRI depicts parts of the primary tumour not detected by CT. There was no significant difference in volume delineation between MR and CT for CTV, PTV, nodal CTV and nodal PTV. MRI volumes for brainstem and spinal cord were significantly smaller due to improved organ definition (p = 0.002). Susceptibility and gradient-related distortions were not found to be clinically significant. Conclusion: MRI improves the definition of tongue base tumours and neurological structures. The use of MRI is recommended for GTV dose-escalation techniques to provide precise depiction of GTV and improved

  6. Large coil task and results of testing US coils

    International Nuclear Information System (INIS)

    Haubenreich, P.N.

    1986-01-01

    The United States, EURATOM, Japan, and Switzerland have collaborated since 1978 in development of superconducting toroidal field coils for fusion reactor applications. The United States provided a test facility nd three coils; the other participants, one coil each. All coils have the same interface dimensions and performance requirements (stable at 8 T), but internal design was decided by each team. Two US coil teams chose bath-cooled NbTi, 10-kA conductors. One developed a Nb 3 Sn conductor, cooled by internal flow, rated at 18 kA. All US coils have diagnostic instrumentation and imbedded heaters that enable stability tests and simulated nuclear heating experiments. In single-coil tests, each coil operated at full current in self-field (6.4 T). In six-coil tests that began in July 1986, one US coil and the Japanese coil hve been successfully operated at full current at 8 T. The other coils have operated as background coils while awaiting their turn as test coil. Coil tests have been informative and results gratifying. The facility has capably supported coil testing and its operation has provided information that will be useful in designing future fusion systems. Coil capabilities beyond nominal design points will be determined

  7. High resolution MR imaging of the hip using pelvic phased-array coil

    Energy Technology Data Exchange (ETDEWEB)

    Niitsu, Mamoru; Mishima, Hajime; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine

    1997-01-01

    A pelvic phased-array coil was applied to obtain high resolution MR images of the hip. Three-mm-thick fast spin-echo images were obtained in seven hips. Images with a pelvic coil enhanced delineation of acetabular labrum and articular cartilage more clearly than those with a body coil or flexible-surface coil. The use of a pelvic coil in imaging of the hip may be of diagnostic value because of its superior delineation. (author)

  8. Open coil traction system.

    Science.gov (United States)

    Vibhute, Pavankumar Janardan

    2012-01-01

    Sliding mechanics have become a popular method for space closure, with the development of preadjusted edgewise appliances. Furthermore, various space closing auxiliaries have been developed and extensively evaluated for their clinical efficiency. Their effectiveness is enhanced with optimum force magnitude and low load deflection rate/force decay. With the advent of nickel-titanium (Ni-Ti) springs in orthodontics, load deflection rates have been markedly reduced. To use Ni-Ti springs, clinicians have to depend upon prefabricated closed coil springs. The open coil traction system, or open coil retraction spring, is developed utilizing Ni-Ti open coil springs for orthodontic space closure. This article describes the fabrication and clinical application of the open coil traction system, which has a number of advantages. It sustains a low load deflection rate with optimum force magnitude, and its design is adjustable for a desired length and force level. It is fail-safe for both activation and deactivation (ie, it cannot be overactivated, and the decompression limit of the open coil is controlled by the operator). The open coil traction system can be offset from the mucosa to help reduce soft tissue impingement.

  9. Program of internal training of the ININ personnel participating in the PERE of the CLV (1998). II. Development and final evaluation

    International Nuclear Information System (INIS)

    Suarez, G.

    1999-04-01

    According to the results of the initial evaluation, he/she was carried out the program of the personnel's of the participant ININ internal training in the PERE of the CLV (1998). The purpose of this report is to describe the development of the one it programs and the results of the final evaluation. (Author)

  10. Coil spring venting arrangement

    International Nuclear Information System (INIS)

    McCugh, R.M.

    1975-01-01

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed

  11. Measurement of a Conduction Cooled Nb3Sn Racetrack Coil

    Science.gov (United States)

    Kim, HS; Kovacs, C.; Rochester, J.; Sumption, MD; Tomsic, M.; Peng, X.; Doll, D.

    2017-12-01

    Use of superconducting coils for wind turbines and electric aircraft is of interest because of the potential for high power density and weight reduction. Here we test a racetrack coil developed as a proof-of-concept for cryogen-free superconducting motors and generators. The coil was wound with 1209 m of 0.7-mm-diameter insulated tube-type Nb3Sn wire. The coil was epoxy-impregnated, instrumented, covered with numerous layers of aluminized mylar insulation, and inserted vertically into a dewar. The system was cooled to 4.2 K, and a few inches of liquid helium was allowed to collect at the bottom of the dewar but below the coil. The coil was cooled by conduction via copper cooling bars were attached to the coil but also were immersed in the liquid helium at their lower ends. Several current tests were performed on the coil, initially in voltage mode, and one run in current mode. The maximum coil Ic at 4.2 K was 480 A, generating 3.06 T at the surface of the coil. The coil met the design targets with a noticeable margin.

  12. Deep brain transcranial magnetic stimulation using variable "Halo coil" system

    Science.gov (United States)

    Meng, Y.; Hadimani, R. L.; Crowther, L. J.; Xu, Z.; Qu, J.; Jiles, D. C.

    2015-05-01

    Transcranial Magnetic Stimulation has the potential to treat various neurological disorders non-invasively and safely. The "Halo coil" configuration can stimulate deeper regions of the brain with lower surface to deep-brain field ratio compared to other coil configurations. The existing "Halo coil" configuration is fixed and is limited in varying the site of stimulation in the brain. We have developed a new system based on the current "Halo coil" design along with a graphical user interface system that enables the larger coil to rotate along the transverse plane. The new system can also enable vertical movement of larger coil. Thus, this adjustable "Halo coil" configuration can stimulate different regions of the brain by adjusting the position and orientation of the larger coil on the head. We have calculated magnetic and electric fields inside a MRI-derived heterogeneous head model for various positions and orientations of the coil. We have also investigated the mechanical and thermal stability of the adjustable "Halo coil" configuration for various positions and orientations of the coil to ensure safe operation of the system.

  13. Ocular MR imaging. Evaluation of different coil setups in a phantom study

    International Nuclear Information System (INIS)

    Erb-Eigner, Katharina; Warmuth, Carsten; Taupitz, Matthias; Bertelmann, Eckart; Hamm, Bernd; Asbach, Patrick

    2013-01-01

    Small loop surface coils are generally recommended for ocular magnetic resonance (MR) imaging, but the optimal coil setup has not been systematically investigated. In this phantom study, we investigated which coil setup of those coils available for our MR imaging system provides the highest signal-to-noise ratio (SNR) in ocular MR imaging at 1.5 tesla. Using a phantom to simulate the eyeball and the orbital fat, we employed loop surface coils of 4- and 6-cm diameter and a multi-channel head coil to obtain images using a T 1 -weighted spin-echo sequence and then measured the SNR for each coil and coil combination. Use of the 6-cm loop coil alone yielded the highest mean SNR (27.5). Even in superficial regions (mesial and temporal), the SNR was higher using the 6-cm loop coil (33.6 and 45.5) than the 4-cm loop coil (28.0 and 33.8). Additional use of the head coil reduced the mean SNR to 10.4. This quantitative analysis suggests that use of a 6-cm loop surface coil offers the best results in ocular MR imaging. Combinations of loop coils or additional use of a head coil cannot be recommended because higher noise degrades image quality. (author)

  14. Extending the self-assembly of coiled-coil hybrids

    NARCIS (Netherlands)

    Robson Marsden, Hana

    2009-01-01

    Of the various biomolecular building blocks in use in nature, coiled-coil forming peptides are amongst those with the most potential as building blocks for the synthetic self-assembly of nanostructures. Native coiled coils have the ability to function in, and influence, complex systems composed of

  15. A periodic table of coiled-coil protein structures.

    Science.gov (United States)

    Moutevelis, Efrosini; Woolfson, Derek N

    2009-01-23

    Coiled coils are protein structure domains with two or more alpha-helices packed together via interlacing of side chains known as knob-into-hole packing. We analysed and classified a large set of coiled-coil structures using a combination of automated and manual methods. This led to a systematic classification that we termed a "periodic table of coiled coils," which we have made available at http://coiledcoils.chm.bris.ac.uk/ccplus/search/periodic_table. In this table, coiled-coil assemblies are arranged in columns with increasing numbers of alpha-helices and in rows of increased complexity. The table provides a framework for understanding possibilities in and limits on coiled-coil structures and a basis for future prediction, engineering and design studies.

  16. LHC bending magnet coil

    CERN Multimedia

    A short test version of coil of wire used for the LHC dipole magnets. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. Magnet coils are made of copper-clad niobium–titanium cables — each wire in the cable consists of 9’000 niobium–titanium filaments ten times finer than a hair.

  17. Borehole induction coil transmitter

    Science.gov (United States)

    Holladay, Gale; Wilt, Michael J.

    2002-01-01

    A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

  18. Transmit coil design for Wireless Power Transfer for medical implants.

    Science.gov (United States)

    Lemdiasov, Rosti; Venkatasubramanian, Arun

    2017-07-01

    A new design approach for the design of transmit coils for Wireless Power Transfer (WPT) is presented. The theoretical formulation involves a figure of merit that has to be maximized to solve for the surface current. Numerical predictions and comparisons with practical measurements for the coil parameters (inductance. resistance) underscore the success of this approach in terms of achieving strong coupling with a receive coil while maintaining low resistance.

  19. On modular stellarator reactor coils

    International Nuclear Information System (INIS)

    Rau, F.; Harmeyer, E.; Kisslinger, J.; Wobig, H.

    1985-01-01

    Modular twisted coils are discussed which produce magnetic fields of the Advanced Stellarator WENDELSTEIN VII-AS type. Reducing the number coils/FP offers advantage for maintenance of coils, but increases the magnetic ripple and B m /B o . Computation of force densities within the coils of ASR and ASB yield local maximum values of about 80 and 180 MN/m 3 , respectively. A system of mutual coil support is being developed. Twisted coils in helical arrangement provide a reactor-sized HELIAC system. In order to reduce the magnetic ripple, a large number of 14 coils/FP in special arrangement is used

  20. TFTR toroidal field coil design

    International Nuclear Information System (INIS)

    Smith, G.E.; Punchard, W.F.B.

    1977-01-01

    The design of the Tokamak Fusion Test Reactor (TFTR) Toroidal Field (TF) magnetic coils is described. The TF coil is a 44-turn, spiral-wound, two-pancake, water-cooled configuration which, at a coil current of 73.3 kiloamperes, produces a 5.2-Tesla field at a major radius of 2.48 meters. The magnetic coils are installed in titanium cases, which transmit the loads generated in the coils to the adjacent supporting structure. The TFTR utilizes 20 of these coils, positioned radially at 18 0 intervals, to provide the required toroidal field. Because it is very highly loaded and subject to tight volume constraints within the machine, the coil presents unique design problems. The TF coil requirements are summarized, the coil configuration is described, and the problems highlighted which have been encountered thus far in the coil design effort, together with the development tests which have been undertaken to verify the design

  1. NCSX Toroidal Field Coil Design

    International Nuclear Information System (INIS)

    Kalish M; Rushinski J; Myatt L; Brooks A; Dahlgren F; Chrzanowski J; Reiersen W; Freudenberg K.

    2005-01-01

    The National Compact Stellarator Experiment (NCSX) is an experimental device whose design and construction is underway at the Department of Energy's Princeton Plasma Physics Laboratory (PPPL). The primary coil systems for the NCSX device consist of the twisted plasma-shaping Modular Coils, the Poloidal Field Coils, and the Toroidal Field (TF) Coils. The TF Coils are D-shaped coils wound from hollow copper conductor, and vacuum impregnated with a glass-epoxy resin system. There are 18 identical, equally spaced TF coils providing 1/R field at the plasma. They operate within a cryostat, and are cooled by LN2, nominally, to 80K. Wedge shaped castings are assembled to the inboard face of these coils, so that inward radial loads are reacted via the nesting of each of the coils against their adjacent partners. This paper outlines the TF Coil design methodology, reviews the analysis results, and summarizes how the design and analysis support the design requirements

  2. Effective arrangement of separated transmit-only/receive-only RF coil for improvement of B1 homogeneity at 7 Tesla

    Science.gov (United States)

    Im, Geun Ho; Seo, Jeong-Hoon; Kim, Kyoung-Nam; Heo, Phil; Chung, Julius Juhyun; Jang, Moon-Sun; Lee, Jung Hee; Kim, Jae-Hun; Kim, Sun I.

    2014-09-01

    This article presents an effective arrangement with shifted transmit (Tx)-only and receive (Rx)-only (TORO) radiofrequency (RF) coils in a single-channel surface coil for improving the magnetic flux ( B 1) homogeneity in an ultra-high field (UHF) magnetic resonance imaging (MRI) scanner. The proposed new methodology for the coil arrangement using the shifted TORO RF coils was demonstrated for coils with 50-mm, 100-mm, and 150-mm-square surfaces and the results were compared to those for general Tx/Rx surface coils with the same dimensions. The computational analysis indicated that a homogeneous B1 field was achieved when the Rx-only coil was shifted in the two-dimensional xy-plane away from the Tx-only coils. Because the proposed coil configuration provides a unique opportunity for increasing the B 1 homogeneity, this feature is likely to increase the feasibility via new coil arrangements of UHF surface design and fabrication.

  3. Coil protection calculator for TFTR

    International Nuclear Information System (INIS)

    Marsala, R.J.; Woolley, R.D.

    1987-01-01

    A new coil protection calculator (CPC) is presented in this paper. It is now being developed for TFTR's magnetic field coils will replace the existing coil fault detector. The existing fault detector sacrifices TFTR operating capability for simplicity. The new CPC will permit operation up to the actual coil limits by accurately and continuously computing coil parameters in real-time. The improvement will allow TFTR to operate with higher plasma currents and will permit the optimization of pulse repetition rates

  4. Deriving robust noncontextuality inequalities from algebraic proofs of the Kochen-Specker theorem: the Peres-Mermin square

    Science.gov (United States)

    Krishna, Anirudh; Spekkens, Robert W.; Wolfe, Elie

    2017-12-01

    When a measurement is compatible with each of two other measurements that are incompatible with one another, these define distinct contexts for the given measurement. The Kochen-Specker theorem rules out models of quantum theory that satisfy a particular assumption of context-independence: that sharp measurements are assigned outcomes both deterministically and independently of their context. This notion of noncontextuality is not suited to a direct experimental test because realistic measurements always have some degree of unsharpness due to noise. However, a generalized notion of noncontextuality has been proposed that is applicable to any experimental procedure, including unsharp measurements, but also preparations as well, and for which a quantum no-go result still holds. According to this notion, the model need only specify a probability distribution over the outcomes of a measurement in a context-independent way, rather than specifying a particular outcome. It also implies novel constraints of context-independence for the representation of preparations. In this article, we describe a general technique for translating proofs of the Kochen-Specker theorem into inequality constraints on realistic experimental statistics, the violation of which witnesses the impossibility of a noncontextual model. We focus on algebraic state-independent proofs, using the Peres-Mermin square as our illustrative example. Our technique yields the necessary and sufficient conditions for a particular set of correlations (between the preparations and the measurements) to admit a noncontextual model. The inequalities thus derived are demonstrably robust to noise. We specify how experimental data must be processed in order to achieve a test of these inequalities. We also provide a criticism of prior proposals for experimental tests of noncontextuality based on the Peres-Mermin square.

  5. Upgrade the intervention levels derived for water and foods, to be include in the PERE 607 procedure the external radiological emergency plan in the Laguna Verde nuclear power plant

    International Nuclear Information System (INIS)

    Llado Castillo, R.; Aguilar Pacheco, R.

    1998-01-01

    The work shows the results obtained in the upgrade the intervention levels derived for water and foods, to be include in the PERE 607 procedure the external radiological emergency plan in the Laguna Verde nuclear power plant

  6. Assessment of early-stage optic nerve invasion in retinoblastoma using high-resolution 1.5 Tesla MRI with surface coils: a multicentre, prospective accuracy study with histopathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Brisse, Herve J. [Institut Curie, Department of Radiology, Paris (France); Institut CURIE, Imaging Department, Paris (France); Graaf, Pim de; Rodjan, Firazia; Jong, Marcus C. de; Castelijns, Jonas A. [VU University Medical Center, Department of Radiology, Amsterdam (Netherlands); Galluzzi, Paolo [Neuroimaging and Neurointerventional Unit (NINT) Azienda Ospedaliera e Universitaria Senese, Siena (Italy); Cosker, Kristel; Savignoni, Alexia [Institut Curie, Department of Biostatistics, Paris (France); Maeder, Philippe [Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne, Department of Radiology, Lausanne (Switzerland); Goericke, Sophia [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Aerts, Isabelle [Institut Curie, Department of Pediatric Oncology, Paris (France); Desjardins, Laurence [Institut Curie, Department of Ophthalmology, Paris (France); Moll, Annette C. [VU University Medical Center, Department of Ophthalmology, Amsterdam (Netherlands); Hadjistilianou, Theodora [Azienda Ospedaliera Universitaria Senese, Department of Ophthalmology, Siena (Italy); Toti, Paolo [University of Siena, Department of Medical Biotechnologies, Pathology Unit, Siena (Italy); Valk, Paul van der [VU University Medical Center, Department of Pathology, Amsterdam (Netherlands); Sastre-Garau, Xavier [Institut Curie, Department of Biopathology, Paris (France); Collaboration: European Retinoblastoma Imaging Collaboration (ERIC)

    2015-05-01

    To assess the accuracy of high-resolution (HR) magnetic resonance imaging (MRI) in diagnosing early-stage optic nerve (ON) invasion in a retinoblastoma cohort. This IRB-approved, prospective multicenter study included 95 patients (55 boys, 40 girls; mean age, 29 months). 1.5-T MRI was performed using surface coils before enucleation, including spin-echo unenhanced and contrast-enhanced (CE) T1-weighted sequences (slice thickness, 2 mm; pixel size <0.3 x 0.3 mm{sup 2}). Images were read by five neuroradiologists blinded to histopathologic findings. ROC curves were constructed with AUC assessment using a bootstrap method. Histopathology identified 41 eyes without ON invasion and 25 with prelaminar, 18 with intralaminar and 12 with postlaminar invasion. All but one were postoperatively classified as stage I by the International Retinoblastoma Staging System. The accuracy of CE-T1 sequences in identifying ON invasion was limited (AUC = 0.64; 95 % CI, 0.55 - 0.72) and not confirmed for postlaminar invasion diagnosis (AUC = 0.64; 95 % CI, 0.47 - 0.82); high specificities (range, 0.64 - 1) and negative predictive values (range, 0.81 - 0.97) were confirmed. HR-MRI with surface coils is recommended to appropriately select retinoblastoma patients eligible for primary enucleation without the risk of IRSS stage II but cannot substitute for pathology in differentiating the first degrees of ON invasion. (orig.)

  7. The use of a phased-array surface coil and breath-holding in MRI of the liver. Comparison of conventional SE, fat-suppressed GRE, and TSE sequences

    International Nuclear Information System (INIS)

    Helmberger, T.; Holzknecht, N.; Lackerbauer, C.A.; Mueller-Lisse, U.; Schnarkowski, P.; Gauger, J.; Reiser, M.

    1995-01-01

    To determine the efficacy of fast MRI techniques using a taylored imaging design (breathhold and array-surface coil), conventional T1-, T2-weighted spin-echo (SE) sequences and breathhold gradient-echo (GRE) T1- and breathhold fast SE T2-weighted images were compared. 20 patients with proven focal liver lesions were studied on a 1.5 Tesla system. Conventional SE T1- und T2-weighted imaging, as well as GRE T1- and fast SE T2-weighted imaging was performed. Fast imaging was done during breathhold using an array-surface coil. For all sequences signal-to-noise ratios (S/N) and liver-to-lesion-contrast ratios (L/L) were measured and statistically compared. Regarding image quality parameters, S/N and L/L, there was no significant difference between the conventional and fast imaging techniques. However, GRE imaging was superior (84.8%) to conventional imaging for breathing and pulsation artifacts, while fast SE T2 imaging was equal regarding breathing artifacts, but superior (51.5%) regarding pulsation artifacts. The number of detected hepatic lesions was identical in all sequences. The fast MRI techniques demonstrated a superiority to conventional imaging regarding image quality and presence of artifacts. (orig.) [de

  8. Coil optimisation for transcranial magnetic stimulation in realistic head geometry.

    Science.gov (United States)

    Koponen, Lari M; Nieminen, Jaakko O; Mutanen, Tuomas P; Stenroos, Matti; Ilmoniemi, Risto J

    Transcranial magnetic stimulation (TMS) allows focal, non-invasive stimulation of the cortex. A TMS pulse is inherently weakly coupled to the cortex; thus, magnetic stimulation requires both high current and high voltage to reach sufficient intensity. These requirements limit, for example, the maximum repetition rate and the maximum number of consecutive pulses with the same coil due to the rise of its temperature. To develop methods to optimise, design, and manufacture energy-efficient TMS coils in realistic head geometry with an arbitrary overall coil shape. We derive a semi-analytical integration scheme for computing the magnetic field energy of an arbitrary surface current distribution, compute the electric field induced by this distribution with a boundary element method, and optimise a TMS coil for focal stimulation. Additionally, we introduce a method for manufacturing such a coil by using Litz wire and a coil former machined from polyvinyl chloride. We designed, manufactured, and validated an optimised TMS coil and applied it to brain stimulation. Our simulations indicate that this coil requires less than half the power of a commercial figure-of-eight coil, with a 41% reduction due to the optimised winding geometry and a partial contribution due to our thinner coil former and reduced conductor height. With the optimised coil, the resting motor threshold of abductor pollicis brevis was reached with the capacitor voltage below 600 V and peak current below 3000 A. The described method allows designing practical TMS coils that have considerably higher efficiency than conventional figure-of-eight coils. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Superconducting coil protection

    International Nuclear Information System (INIS)

    Woods, E.L.

    1975-01-01

    The protection system is based on a two-phase construction program. Phase I is the development of a reliable hardwired relay control system with a digital loop utilizing firmware and a microprocessor controller. Phase II is an expansion of the digital loop to include many heretofore unmonitored coil variables. These new monitored variables will be utilized to establish early quench detection and to formulate confirmation techniques of the quench detection mechanism. Established quench detection methods are discussed and a new approach to quench detection is presented. The new circuit is insensitive to external pulsed magnetic fields and the associated induced voltages. Reliability aspects of the coil protection system are discussed with respect to shutdowns of superconducting coil systems. Redundance and digital system methods are presented as related topics

  10. NET model coil test possibilities

    International Nuclear Information System (INIS)

    Erb, J.; Gruenhagen, A.; Herz, W.; Jentzsch, K.; Komarek, P.; Lotz, E.; Malang, S.; Maurer, W.; Noether, G.; Ulbricht, A.; Vogt, A.; Zahn, G.; Horvath, I.; Kwasnitza, K.; Marinucci, C.; Pasztor, G.; Sborchia, C.; Weymuth, P.; Peters, A.; Roeterdink, A.

    1987-11-01

    A single full size coil for NET/INTOR represents an investment of the order of 40 MUC (Million Unit Costs). Before such an amount of money or even more for the 16 TF coils is invested as much risks as possible must be eliminated by a comprehensive development programme. In the course of such a programme a coil technology verification test should finally prove the feasibility of NET/INTOR TF coils. This study report is almost exclusively dealing with such a verification test by model coil testing. These coils will be built out of two Nb 3 Sn-conductors based on two concepts already under development and investigation. Two possible coil arrangements are discussed: A cluster facility, where two model coils out of the two Nb 3 TF-conductors are used, and the already tested LCT-coils producing a background field. A solenoid arrangement, where in addition to the two TF model coils another model coil out of a PF-conductor for the central PF-coils of NET/INTOR is used instead of LCT background coils. Technical advantages and disadvantages are worked out in order to compare and judge both facilities. Costs estimates and the time schedules broaden the base for a decision about the realisation of such a facility. (orig.) [de

  11. Program of internal training of the ININ personnel participating in the PERE of the CLV (1998). II. Development and final evaluation; Programa de capacitacion interna del personal del ININ participante en el PERE de la CLV (1998). II. Desarrollo y evaluacion final

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1999-04-15

    According to the results of the initial evaluation, he/she was carried out the program of the personnel's of the participant ININ internal training in the PERE of the CLV (1998). The purpose of this report is to describe the development of the one it programs and the results of the final evaluation. (Author)

  12. Trim coil power supplies

    International Nuclear Information System (INIS)

    Haisler, R.; Peeler, H.; Zajicek, W.

    1985-01-01

    The 18 trim coil power supplies have been constructed and are now in place in the K500 pit and pit mezzanine. Final wiring of the primary power and control power is proceeding along with installation of cooling water supplies. The supplies are expected to be ready for final testing into resistive loads at the beginning of June, 1985

  13. Eccentric Coil Test Facility (ECTF)

    International Nuclear Information System (INIS)

    Burn, P.B.; Walstrom, P.L.; Anderson, W.C.; Marguerat, E.F.

    1975-01-01

    The conceptual design of a facility for testing superconducting coils under some conditions peculiar to tokamak systems is given. A primary element of the proposed facility is a large 25 MJ background solenoid. Discussions of the mechanical structure, the stress distribution and the thermal stability for this coil are included. The systems for controlling the facility and diagnosing test coil behavior are also described

  14. Modular coils: a promising toroidal-reactor-coil system

    International Nuclear Information System (INIS)

    Chu, T.K.; Furth, H.P.; Johnson, J.L.; Ludescher, C.; Weimer, K.E.

    1981-04-01

    The concept of modular coils originated from a need to find reactor-relevant stellarator windings, but its usefulness can be extended to provide an externally applied, additional rotational transform in tokamaks. Considerations of (1) basic principles of modular coils, (2) types of coils, (3) types of configurations (general, helically symmetric, helically asymmetric, with magnetic well, with magnetic hill), (4) types of rotational transform profile, and (5) structure and origin of ripples are given. These results show that modular coils can offer a wide range of vacuum magnetic field configurations, some of which cannot be obtained with the classical stellarator or torsatron coil configuration

  15. Optimization of Coil Element Configurations for a Matrix Gradient Coil.

    Science.gov (United States)

    Kroboth, Stefan; Layton, Kelvin J; Jia, Feng; Littin, Sebastian; Yu, Huijun; Hennig, Jurgen; Zaitsev, Maxim

    2018-01-01

    Recently, matrix gradient coils (also termed multi-coils or multi-coil arrays) were introduced for imaging and B 0 shimming with 24, 48, and even 84 coil elements. However, in imaging applications, providing one amplifier per coil element is not always feasible due to high cost and technical complexity. In this simulation study, we show that an 84-channel matrix gradient coil (head insert for brain imaging) is able to create a wide variety of field shapes even if the number of amplifiers is reduced. An optimization algorithm was implemented that obtains groups of coil elements, such that a desired target field can be created by driving each group with an amplifier. This limits the number of amplifiers to the number of coil element groups. Simulated annealing is used due to the NP-hard combinatorial nature of the given problem. A spherical harmonic basis set up to the full third order within a sphere of 20-cm diameter in the center of the coil was investigated as target fields. We show that the median normalized least squares error for all target fields is below approximately 5% for 12 or more amplifiers. At the same time, the dissipated power stays within reasonable limits. With a relatively small set of amplifiers, switches can be used to sequentially generate spherical harmonics up to third order. The costs associated with a matrix gradient coil can be lowered, which increases the practical utility of matrix gradient coils.

  16. Anatomy of the fingers in MR imaging using a high resolution surface coil; Die Anatomie der Finger in der MRT unter Anwendung einer Hochaufloesungsspule

    Energy Technology Data Exchange (ETDEWEB)

    Maeurer, J. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Mueller, H.F. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Lemke, A.J. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Requardt, R. [Siemens AG, Erlangen (Germany); Stein, I. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Schedel, H. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Langer, R. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Felix, R. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)

    1994-12-31

    MR-images of the fingers of twenty healthy volunteers were obtained at a 1,5-T whole-body system with a high resolution coil. Additionally, the fingers of two formalin-fixed anatomical specismen were imaged, fronzen and then subsequently sectioned for anatomic correlation. Measurements were recorded with a slice thickness of 2 mm. A 256x256 matrix and a 2,5 cam fiel of view (FOV) were used resulting in a pixel size of 0,01 mm{sup 2}. Based on the excellent depiction of anatomic detail and contrast resolution high resolution MRI of the fingers enabled identification of osseous and cartilaginous structures, as well as delineation of tendons, ligaments blood-vessels and dermal layers. (orig.) [Deutsch] An einem 1,5-T-Ganzkoerpertomographen wurden die Finger von 20 gesunden Probanden mit einer Hochaufloesungsspule zur Darstellung der Anatomie untersucht. Zum Vergleich erfolgte die Abbildung der anatomischen Strukturen an zwei formol- und alkoholfixierten Leichepraeparaten der Hand mittels MRT. Im Anschluss wurden die untersuchten Regionen am tiefgefrorenen Praeparat mit einer Bandsaege nachgeschnitten. Die MR-Messungen wurden mit einer Schichtdicke von 3 mm, einem Field of View (FOV) von 25 mm und einer Matrix von 256x256 Pixel durchgefuehrt. Die daraus resultierende Pixelgroesse betrug 0,01 mm{sup 2}. Der Weichteilkontrast und die hohe Ortsaufloesung ermoeglichten die Identifikation von Knochen- und Knorpelstrukturen sowie die Abgrenzung von Sehnen, Baendern, Blutgefaessen und Hautschichten. (orig.)

  17. Sub-20 nm Stable Micelles Based on a Mixture of Coiled-Coils: A Platform for Controlled Ligand Presentation.

    Science.gov (United States)

    Ang, JooChuan; Ma, Dan; Jung, Benson T; Keten, Sinan; Xu, Ting

    2017-11-13

    Ligand-functionalized, multivalent nanoparticles have been extensively studied for biomedical applications from imaging agents to drug delivery vehicles. However, the ligand cluster size is usually heterogeneous and the local valency is ill-defined. Here, we present a mixed micelle platform hierarchically self-assembled from a mixture of two amphiphilic 3-helix and 4-helix peptide-polyethylene glycol (PEG)-lipid hybrid conjugates. We demonstrate that the local multivalent ligand cluster size on the micelle surface can be controlled based on the coiled-coil oligomeric state. The oligomeric states of mixed peptide bundles were found to be in their individual native states. Similarly, mixed micelles indicate the orthogonal self-association of coiled-coil amphiphiles. Using differential scanning calorimetry, fluorescence recovery spectroscopy, and coarse-grained molecular dynamics simulation, we studied the distribution of coiled-coil bundles within the mixed micelles and observed migration of coiled-coils into nanodomains within the sub-20 nm mixed micelle. This report provides important insights into the assembly and formation of nanophase-separated micelles with precise control over the local multivalent state of ligands on the micelle surface.

  18. Supporting device for Toroidal coils

    International Nuclear Information System (INIS)

    Araki, Takao.

    1985-01-01

    Purpose: To reduce the response of a toroidal coil supporting device upon earthquakes and improve the earthquake proofness in a tokamak type thermonuclear device. Constitution: Structural materials having large longitudinal modulus and enduring great stresses, for example, stainless steels are used as the toroidal coil supporting legs and heat insulating structural materials are embedded in a nuclear reactor base mats below the supporting legs. Furthermore, heat insulating concretes are spiked around the heat insulating structural materials to prevent the intrusion of heat to the toroidal coils. The toroidal coils are kept at cryogenic state and superconductive state for the conductors. In this way, the period of proper vibrations of the toroidal coils and the toroidal coil supporting structures can be shortened thereby decreasing the seismic response. Furthermore, since the strength of the supporting legs is increased, the earthquake proofness of the coils can be improved. (Kamimura, M.)

  19. Comparison of endorectal coil and nonendorectal coil T2W and diffusion-weighted MRI at 3 Tesla for localizing prostate cancer: correlation with whole-mount histopathology.

    Science.gov (United States)

    Turkbey, Baris; Merino, Maria J; Gallardo, Elma Carvajal; Shah, Vijay; Aras, Omer; Bernardo, Marcelino; Mena, Esther; Daar, Dagane; Rastinehad, Ardeshir R; Linehan, W Marston; Wood, Bradford J; Pinto, Peter A; Choyke, Peter L

    2014-06-01

    To compare utility of T2-weighted (T2W) MRI and diffusion-weighted MRI (DWI-MRI) obtained with and without an endorectal coil at 3 Tesla (T) for localizing prostate cancer. This Institutional Review Board-approved study included 20 patients (median prostate-specific antigen, 8.4 ng/mL). Patients underwent consecutive prostate MRIs at 3T, first with a surface coil alone, then with combination of surface, endorectal coils (dual coil) followed by robotic assisted radical prostatectomy. Lesions were mapped at time of acquisition on dual-coil T2W, DWI-MRI. To avoid bias, 6 months later nonendorectal coil T2W, DWI-MRI were mapped. Both MRI evaluations were performed by two readers blinded to pathology with differences resolved by consensus. A lesion-based correlation with whole-mount histopathology was performed. At histopathology 51 cancer foci were present ranging in size from 2 to 60 mm. The sensitivity of the endorectal dual-coil, nonendorectal coil MRIs were 0.76, 0.45, respectively. PPVs for endorectal dual-coil, nonendorectal coil MRI were 0.80, 0.64, respectively. Mean size of detected lesions with nonendorectal coil MRI were larger than those detected by dual-coil MRI (22 mm versus 17.4 mm). Dual-coil prostate MRI detected more cancer foci than nonendorectal coil MRI. While nonendorectal coil MRI is an attractive alternative, physicians performing prostate MRI should be aware of its limitations. Copyright © 2013 Wiley Periodicals, Inc.

  20. Impedance of curved rectangular spiral coils around a conductive cylinder

    Science.gov (United States)

    Burke, S. K.; Ditchburn, R. J.; Theodoulidis, T. P.

    2008-07-01

    Eddy-current induction due to a thin conformable coil wrapped around a long conductive cylinder is examined using a second-order vector potential formalism. Compact closed-form expressions are derived for the self- and mutual impedances of curved rectangular spiral coils (i) in free space and (ii) when wrapped around the surface of the cylindrical rod. The validity of these expressions was tested against the results of a systematic series of experiments using a cylindrical Al-alloy rod and conformable coils manufactured using flexible printed-circuit-board technology. The theoretical expressions were in very good agreement with the experimental measurements. The significance of the results for eddy-current nondestructive inspection using flexible coils and flexible coil arrays is discussed.

  1. Coil Optimization for HTS Machines

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Abrahamsen, Asger Bech

    An optimization approach of HTS coils in HTS synchronous machines (SM) is presented. The optimization is aimed at high power SM suitable for direct driven wind turbines applications. The optimization process was applied to a general radial flux machine with a peak air gap flux density of ~3T...... is suitable for which coil segment is presented. Thus, the performed study gives valuable input for the coil design of HTS machines ensuring optimal usage of HTS tapes....

  2. Large superconducting coil fabrication development

    International Nuclear Information System (INIS)

    Brown, R.L.; Allred, E.L.; Anderson, W.C.; Burn, P.B.; Deaderick, R.I.; Henderson, G.M.; Marguerat, E.F.

    1975-01-01

    Toroidal fields for some fusion devices will be produced by an array of large superconducting coils. Their size, space limitation, and field requirements dictate that they be high performance coils. Once installed, accessibility for maintenance and repairs is severely restricted; therefore, good reliability is an obvious necessity. Sufficient coil fabrication will be undertaken to develop and test methods that are reliable, fast, and economical. Industrial participation will be encouraged from the outset to insure smooth transition from development phases to production phases. Initially, practice equipment for three meter bore circular coils will be developed. Oval shape coil forms will be included in the practice facility later. Equipment that is more automated will be developed with the expectation of winding faster and obtaining good coil quality. Alternate types of coil construction, methods of winding and insulating, will be investigated. Handling and assembly problems will be studied. All technology developed must be feasible for scaling up when much larger coils are needed. Experimental power reactors may need coils having six meter or larger bores

  3. Device for supporting a toroidal coil in a toroidal type nuclear fusion device

    International Nuclear Information System (INIS)

    Kitazawa, Hakaru; Sato, Hiroshi.

    1975-01-01

    Object: To easily manufacture a center block having a strength sufficient to withstand an electromagnetic force exerted on the center of toroidal of a toroidal coil and to increase its reliability. Structure: In a device for supporting toroidal coils wherein the electromagnetic force exerted on the center of toroidal of a plurality of toroidal coils arranged in toroidal fashion, the contact surface between the toroidal coil and the center block is arranged parallel to the center axis of toroidal so as to receive the electromagnetic force exerted on the center of toroidal of the toroidal coil as the component of force in a radial direction. (Taniai, N.)

  4. Detailed 3D models of the induced electric field of transcranial magnetic stimulation coils

    International Nuclear Information System (INIS)

    Salinas, F S; Lancaster, J L; Fox, P T

    2007-01-01

    Previous models neglected contributions from current elements spanning the full geometric extent of wires in transcranial magnetic stimulation (TMS) coils. A detailed account of TMS coil wiring geometry is shown to provide significant improvements in the accuracy of electric field (E-field) models. Modeling E-field dependence based on the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed E-field models were accurate up to the surface of the coil body (within 0.5% of measured) where simple models were often inadequate (up to 32% different from measured)

  5. Numerical characterization of a flexible circular coil for magnetic resonance imaging

    Science.gov (United States)

    Bautista, T.; Hernandez, R.; Solis-Najera, S. E.; Rodriguez, A. O.

    2012-10-01

    Numerical simulations of the magnetic field generated by a flexible surface coil were conducted to study its behavior for applications of animal models at 7 Tesla. This coil design is able to fully cover a volume of interest. The Finite Difference Method in Time Domain (FDTD) was used because of its ability to accurately model complex problems in electromagnetism. This particular coil design is best suited for regions of interests with a spherical shape, since B1 uniformity is not significantly attenuated as in the case of a circular-loop coil. It still remains to investigate the feasibility to actually construct a coil prototype.

  6. Triple Halo Coil: Development and Comparison with Other TMS Coils

    Science.gov (United States)

    Rastogi, Priyam; Hadimani, Ravi; Jiles, David

    Transcranial Magnetic Stimulation (TMS) is a non-invasive stimulation technique that can be used for the treatment of various neurological disorders such as Parkinson's Disease, PTSD, TBI and anxiety by regulating synaptic activity. TMS is FDA approved for the treatment of major depressive disorder. There is a critical need to develop deep TMS coils that can stimulate deeper regions of the brain without excessively stimulating the cortex in order to provide an alternative to surgical methods. We have developed a novel multi-coil configuration called ``Triple Halo Coil'' (THC) that can stimulate deep brain regions. Investigation of induced electric and magnetic field in these regions have been achieved by computer modelling. Comparison of the results due to THC configuration have been conducted with other TMS coils such as ``Halo Coil'', circular coil and ``Figure of Eight'' coil. There was an improvement of more than 15 times in the strength of magnetic field, induced by THC configuration at 10 cm below the vertex of the head when compared with the ``Figure of Eight'' coil alone. Carver Charitable Trust.

  7. The coiled coil motif in polymer drug delivery systems

    Czech Academy of Sciences Publication Activity Database

    Pechar, Michal; Pola, Robert

    2013-01-01

    Roč. 31, č. 1 (2013), s. 90-96 ISSN 0734-9750 R&D Projects: GA ČR GA203/08/0543; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505 Keywords : coiled coil * hydrophilic polymer * recombinant protein Subject RIV: CD - Macromolecular Chemistry Impact factor: 8.905, year: 2013

  8. Kuidas olla peresõbralik tööandja : muret valmistab erisoodustusmaks, kuid hoolivus on ülesanne number üks

    Index Scriptorium Estoniae

    2008-01-01

    Oma ettevõtte peresõbralikkusest ja paindlikkusest räägivad Kädi Vestberg HR factory OÜ-st, Kadri Johanson CV-Keskusest, Kati Oja reisibüroost Estravel, Helena Erm Scania Eesti AS-ist, Moonika Kähr kinnisvarafirmast Uus Maa, Liina Oks Sampo pangast, Reet Treial Balti Investeeringute Grupi Pank AS-ist, Ülle Matt elektroonikafirmast Elcoteq, Silvia Savik Nukuteatrist, Ülle Filin Tele2 Eesti AS-ist, Sirje Tammiste Sirje Tammiste Konsultandibüroost, Getri Järvsoo Fortum Termest AS-ist ja Kärt Kirso AS-ist Kalev Chocolate Factory

  9. Development work for the Japanese LCT coil and its design and construction

    International Nuclear Information System (INIS)

    Shimamoto, Susumu; Ando, Toshinari; Tsuji, Hiroshi; Yasukochi, Ko

    1984-01-01

    This paper describes design, verification tests, and construction of the Japanese test coil for the Large Coil Task (LCT). Japan Atomic Energy Research Institute (JAERI) signed on the LCT international agreement under the International Energy Agency (IEA) in 1978, and since then JAERI has been working to develop the Japanese LCT coil to explore the problems of design and construction of tokamak toroidal coil. Based on the common requirements of the LCT, the Japanese LCT coil was designed to be a pool-cooled NbTi fully-stabilized coil whose operating current is 10,220 A at 8 T. Through research and development of the Japanese LCT coil, new advances in the super-conducting coil technology were obtained, such as mechanically and chemically treated conductor surface that has high heat transfer about four times as much as usual ones, nitrogen-strengthened stainless steel that has the yield strength twice as much as usual stainless steel, NbTi filaments those have the critical current density twice as much as those before LCT, and so on. These advances have enabled to construct the Japanese LCT coil and it was completed in the spring of 1982. During the construction of the coil, new fabrication techniques were obtained to wind large current conductor into a mechanically rigid coil and thus to construct a totally stable large coil. (author)

  10. Coil response inversion for very early time modelling of helicopter-borne time-domain electromagnetic data and mapping of near-surface geological layers

    DEFF Research Database (Denmark)

    Schamper, Cyril Noel Clarence; Auken, Esben; Sørensen, Kurt Ingvard K.I.

    2014-01-01

    Very early times in the order of 2-3 μs from the end of the turn-off ramp for time-domain electromagnetic systems are crucial for obtaining a detailed resolution of the near-surface geology in the depth interval 0-20 m. For transient electromagnetic systems working in the off time, an electric cu...... resolution of shallow geological layers in the depth interval 0-20 m. This is proved by comparing results from the airborne electromagnetic survey to more than 100 km of Electrical Resistivity Tomography measured with 5 m electrode spacing.......Very early times in the order of 2-3 μs from the end of the turn-off ramp for time-domain electromagnetic systems are crucial for obtaining a detailed resolution of the near-surface geology in the depth interval 0-20 m. For transient electromagnetic systems working in the off time, an electric...

  11. Endothelial cell proliferation in swine experimental aneurysm after coil embolization.

    Directory of Open Access Journals (Sweden)

    Yumiko Mitome-Mishima

    Full Text Available After coil embolization, recanalization in cerebral aneurysms adversely influences long-term prognosis. Proliferation of endothelial cells on the coil surface may reduce the incidence of recanalization and further improve outcomes after coil embolization. We aimed to map the expression of proliferating tissue over the aneurysmal orifice and define the temporal profile of tissue growth in a swine experimental aneurysm model. We compared the outcomes after spontaneous thrombosis with those of coil embolization using histological and morphological techniques. In aneurysms that we not coiled, spontaneous thrombosis was observed, and weak, easily detachable proliferating tissue was evident in the aneurysmal neck. In contrast, in the coil embolization group, histological analysis showed endothelial-like cells lining the aneurysmal opening. Moreover, immunohistochemical and morphological analysis suggested that these cells were immature endothelial cells. Our results indicated the existence of endothelial cell proliferation 1 week after coil embolization and showed immature endothelial cells in septal tissue between the systemic circulation and the aneurysm. These findings suggest that endothelial cells are lead to and proliferate in the former aneurysmal orifice. This is the first examination to evaluate the temporal change of proliferating tissue in a swine experimental aneurysm model.

  12. The IEA Large Coil Task

    International Nuclear Information System (INIS)

    Beard, D.S.; Klose, W.; Shimamoto, S.; Vecsey, G.

    1988-01-01

    A multinational program of cooperative research, development, demonstrations, and exchanges of information on superconducting magnets for fusion was initiated in 1977 under an IEA agreement. The first major step in the development of TF magnets was called the Large Coil Task. Participants in LCT were the U.S. DOE, EURATOM, JAERI, and the Departement Federal de l'Interieur of Switzerland. The goals of LCT were to obtain experimental data, to demonstrate reliable operation of large superconducting coils, and to prove design principles and fabrication techniques being considered for the toroidal magnets of thermonuclear reactors. These goals were to be accomplished through coordinated but largely independent design, development, and construction of six test coils, followed by collaborative testing in a compact toroidal test array at fields of 8 T and higher. Under the terms of the IEA Agreement, the United States built and operated the test facility at Oak Ridge and provided three test coils. The other participants provided one coil each. Information on design and manufacturing and all test data were shared by all. The LCT team of each participant included a government laboratory and industrial partners or contractors. The last coil was completed in 1985, and the test assembly was completed in October of that year. Over the next 23 months, the six-coil array was cooled down and extensive testing was performed. Results were gratifying, as tests achieved design-point performance and well beyond. (Each coil reached a peak field of 9 T.) Experiments elucidated coil behavior, delineated limits of operability, and demonstrated coil safety. (orig./KP)

  13. Superconducting cyclotron magnet coil short

    International Nuclear Information System (INIS)

    Mallory, M.L.; Blosser, H.G.; Clark, D.J.; Launer, H.; Lawton, D.; Miller, P.; Resmini, F.

    1982-01-01

    In February 1981, a short circuit appeared in the superconducting coil of the K500 cyclotron. The short is resistive in character and therefore has no effect on steady state operation of the magnet. The resistance of the short varies, sometimes being below threshold of detection as a heat load on the cooling system and sometimes being significant. The resistance under certain conditions shows approximately cyclic phenomena with time constants in the range of seconds and other approximately cyclic phenomena which correlate with gross operating parameters of the magnet (shifting current from one coil to another at high field and lowering and raising the liquid helium level). A number of diagnostic studies of the short have been made, using 1) an array of flux sensing loops to sense the magnetic effect of the short, 2) voltage comparisons between upper and lower sections of the coil, 3) comparisons of forces in the nine member coil support system and 4) the effect of the short on the thermal charactersitics of the coil. Insulation failure or a metal chip shorting out turns have been explored in some detail but a convincing determination of the exact cause of the short may never be available, (even the extreme step of unwinding the coil having a significant probability that an imperfection with the observed characteristics would pass unnoticed). Analysis of the characteristics of the short indicated that the most serious consequence would be failure of the coils mechanical support system in the event that the magnet was quickly discharged, as in a dump or quench. To deal with this hazard, the support system has been modified by installing solid supports which prevent the coil from moving by an amount sufficient to damage the support system. We have also reexamined the data and calculations used in the original coil design and have made some additional measurements of the properties of the materials (yield strength, friction coefficient, Young's modulus) used in the

  14. Superconducting poloidal coils for STARFIRE commercial reactor

    International Nuclear Information System (INIS)

    Wang, S.T.; Evans, K. Jr.; Turner, L.R.; Huang, Y.C.; Prater, R.; Alcorn, J.

    1979-01-01

    STARFIRE is considered to be the tenth commercial tokamak power plant. A preliminary design study on its superconducting poloidal coil system is presented. Key features of the design studies are: the elimination of the ohmic heating coil; the trade-off studies of the equilibrium field coil locations; and the development of a conceptual design for the superconducting equilibrium field coils. Described are the 100 kA cryostable conductor design, the coil structure, and evaluation of the coil forces

  15. High-resolution magnetic resonance of the extracranial facial nerve and parotid duct: demonstration of the branches of the intraparotid facial nerve and its relation to parotid tumours by MRI with a surface coil

    International Nuclear Information System (INIS)

    Takahashi, N.; Okamoto, K.; Ohkubo, M.; Kawana, M.

    2005-01-01

    AIM: To investigate the usefulness of high-resolution MR imaging in the evaluation of the extracranial facial nerve, compared with surgical findings. MATERIALS AND METHODS: Thirteen patients with benign parotid tumours were studied on a 1.5-T MR system with a 3 in circular surface coil. High-resolution T1-weighted spin-echo, T2-weighted fast spin-echo, and three-dimensional gradient-recalled acquisition in the steady state (GRASS) images were obtained in the axial planes. Oblique reformatted images were generated. Tumours, parotid ducts and facial nerves were identified on these images. The relationship of the tumours to the facial nerves was confirmed at surgery. RESULTS: Facial nerves appeared as linear structures of low intensity on all pulse sequences. The main trunks and cervicofacial and temporofacial divisions of the facial nerves were identified in 100%, 84.1% and 53.8% of GRASS images, respectively. Parotid ducts appeared as structures of low intensity on T1-weighted (66.6%) and GRASS images (81.8%), and as structures of very high intensity on T2-weighted images (91.7%). The relationships of the tumours to the facial nerves were correctly diagnosed in 11 (91.7%) of 12 cases. CONCLUSION: High-resolution MR imaging depicts the extracranial facial nerve and the parotid duct, and is useful for preoperative evaluation of parotid gland tumours

  16. The ability to identify the intraparotid facial nerve for locating parotid gland lesions in comparison to other indirect landmark methods: evaluation by 3.0 T MR imaging with surface coils

    Energy Technology Data Exchange (ETDEWEB)

    Ishibashi, Mana; Fujii, Shinya; Nishihara, Keisuke; Matsusue, Eiji; Kodani, Kazuhiko; Kaminou, Toshio; Ogawa, Toshihide [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori (Japan); Kawamoto, Katsuyuki [Tottori University, Division of Otolaryngology, Head and Neck Surgery, Department of Medicine of Sensory and Motor Organs, Faculty of Medicine, Tottori (Japan)

    2010-11-15

    It is important to know whether a parotid gland lesion is in the superficial or deep lobe for preoperative planning. We aimed to investigate the ability of 3.0 T magnetic resonance (MR) imaging with surface coils to identify the intraparotid facial nerve and locate parotid gland lesions, in comparison to other indirect landmark methods. We retrospectively evaluated 50 consecutive patients with primary parotid gland lesions. The position of the facial nerve was determined by tracing the nerve in the stylomastoid foramen and then following it on sequential MR sections through the parotid gland. The retromandibular vein and the facial nerve line (FN line) were also identified. For each radiologist and each method, we determined the diagnostic ability for deep lobe lesions and superficial lobe lesions, as well as accuracy. These abilities were compared among the three methods using the Chi-square test with Yates' correction. Mean diagnostic ability for deep lobe lesions, the diagnostic ability for superficial lobe lesions, and accuracy were 92%, 86%, 87%, respectively, for the direct identification method; 67%, 89%, 86%, respectively, for the retromandibular vein method; and 25%, 99%, 90%, respectively, for the FN line method. The direct identification method had significantly higher diagnostic ability for deep lesions than the FN line method (P < 0.01), but significantly lower diagnostic ability for superficial lobe lesions than the FN line method (P < 0.01). Direct identification of the intraparotid facial nerve enables parotid gland lesions to be correctly located, particularly those in the deep lobes. (orig.)

  17. High-resolution magnetic resonance of the extracranial facial nerve and parotid duct: demonstration of the branches of the intraparotid facial nerve and its relation to parotid tumours by MRI with a surface coil

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, N. [Department of Radiology, Niigata University Faculty of Medicine, Niigata (Japan) and Department of Radiology, Niigata City General Hospital, Niigata (Japan)]. E-mail: nandtr@hosp.niigata.niigata.jp; Okamoto, K. [Department of Radiology, Niigata University Faculty of Medicine, Niigata (Japan); Ohkubo, M. [Department of Radiotechnology, Niigata University Faculty of Medicine, Niigata (Japan); Kawana, M. [Department of Otorhinolaryngology, Niigata University Faculty of Medicine, Niigata (Japan)

    2005-03-01

    AIM: To investigate the usefulness of high-resolution MR imaging in the evaluation of the extracranial facial nerve, compared with surgical findings. MATERIALS AND METHODS: Thirteen patients with benign parotid tumours were studied on a 1.5-T MR system with a 3 in circular surface coil. High-resolution T1-weighted spin-echo, T2-weighted fast spin-echo, and three-dimensional gradient-recalled acquisition in the steady state (GRASS) images were obtained in the axial planes. Oblique reformatted images were generated. Tumours, parotid ducts and facial nerves were identified on these images. The relationship of the tumours to the facial nerves was confirmed at surgery. RESULTS: Facial nerves appeared as linear structures of low intensity on all pulse sequences. The main trunks and cervicofacial and temporofacial divisions of the facial nerves were identified in 100%, 84.1% and 53.8% of GRASS images, respectively. Parotid ducts appeared as structures of low intensity on T1-weighted (66.6%) and GRASS images (81.8%), and as structures of very high intensity on T2-weighted images (91.7%). The relationships of the tumours to the facial nerves were correctly diagnosed in 11 (91.7%) of 12 cases. CONCLUSION: High-resolution MR imaging depicts the extracranial facial nerve and the parotid duct, and is useful for preoperative evaluation of parotid gland tumours.

  18. A high temperature superconductor tape RF receiver coil for a low field magnetic resonance imaging system

    International Nuclear Information System (INIS)

    Cheng, M C; Yan, B P; Lee, K H; Ma, Q Y; Yang, E S

    2005-01-01

    High temperature superconductor (HTS) thin films have been applied in making a low loss RF receiver coil for improving magnetic resonance imaging image quality. However, the application of these coils is severely limited by their limited field of view (FOV). Stringent fabrication environment requirements and high cost are further limitations. In this paper, we propose a simpler method for designing and fabricating HTS coils. Using industrial silver alloy sheathed Bi (2-x) Pb x Sr 2 Ca 2 Cu 3 O 10 (Bi-2223) HTS tapes, a five-inch single-turn HTS solenoid coil has been developed, and human wrist images have been acquired with this coil. The HTS tape coil has demonstrated an enhanced FOV over a six-inch YBCO thin film surface coil at 77 K with comparable signal-to-noise ratio

  19. Impact of magnetic field strength and receiver coil in ocular MRI: a phantom and patient study.

    Science.gov (United States)

    Erb-Eigner, K; Warmuth, C; Taupitz, M; Willerding, G; Bertelmann, E; Asbach, P

    2013-09-01

    Generally, high-resolution MRI of the eye is performed with small loop surface coils. The purpose of this phantom and patient study was to investigate the influence of magnetic field strength and receiver coils on image quality in ocular MRI. The eyeball and the complex geometry of the facial bone were simulated by a skull phantom with swine eyes. MR images were acquired with two small loop surface coils with diameters of 4 cm and 7 cm and with a multi-channel head coil at 1.5 and 3 Tesla, respectively. Furthermore, MRI of the eye was performed prospectively in 20 patients at 1.5 Tesla (7 cm loop surface coil) and 3 Tesla (head coil). These images were analysed qualitatively and quantitatively and statistical significance was tested using the Wilcoxon-signed-rank test (a p-value of less than 0.05 was considered to indicate statistical significance). The analysis of the phantom images yielded the highest mean signal-to-noise ratio (SNR) at 3 Tesla with the use of the 4 cm loop surface coil. In the phantom experiment as well as in the patient studies the SNR was higher at 1.5 Tesla by applying the 7 cm surface coil than at 3 Tesla by applying the head coil. Concerning the delineation of anatomic structures no statistically significant differences were found. Our results show that the influence of small loop surface coils on image quality (expressed in SNR) in ocular MRI is higher than the influence of the magnetic field strength. The similar visibility of detailed anatomy leads to the conclusion that the image quality of ocular MRI at 3 Tesla remains acceptable by applying the head coil as a receiver coil. © Georg Thieme Verlag KG Stuttgart · New York.

  20. El bàcul de Sant Pere d'Àger: la pèrdua d'un unicum

    Directory of Open Access Journals (Sweden)

    Matas i Blanxart, Maria Teresa

    1999-12-01

    Full Text Available This study consists of an investigation about one missing crosier made of champlevé enamel. This object comes from the Sant Pere d'Ager church (Lleida. This piece is an unicum inside the enamels corpus of Catalonia for its personal iconography. We think that this piece of work by Limoges dates from the end of the 12th century or from the beginning of the 13th century.[fr] Nous présentons dans cet article un étude d'une crosse d'émail champlevé procédant de l'église de Sant Pere d'Ager (Lleida. Il est aujourd'hui perdu. Cet object pour la tematique iconographique est un unicum dans le corpus des émauxs champlevé catalans. Nous pouvons situer la chronologie de cette crosse en cuivre champlevé émaillé et doré, dans l'oeuvre de Limoges des derniers années du siècle XIIᵉ ou la première partie du XIIIᵉ siècle.

  1. Design considerations in coiled-coil fusion constructs for the structural determination of a problematic region of the human cardiac myosin rod

    Energy Technology Data Exchange (ETDEWEB)

    Andreas, Michael P.; Ajay, Gautam; Gellings, Jaclyn A.; Rayment, Ivan (UW)

    2017-12-01

    X-ray structural determination of segments of the myosin rod has proved difficult because of the strong salt-dependent aggregation properties and repeating pattern of charges on the surface of the coiled-coil that lead to the formation of paracrystals. This problem has been resolved in part through the use of globular assembly domains that improve protein folding and prevent aggregation. The primary consideration now in designing coiled-coil fusion constructs for myosin is deciding where to truncate the coiled-coil and which amino acid residues to include from the folding domain. This is especially important for myosin that contains numerous regions of low predicted coiled-coil propensity. Here we describe the strategy adopted to determine the structure of the region that extends from Arg1677 – Leu1797 that included two areas that do not show a strong sequence signature of a conventional left-handed coiled coil or canonical heptad repeat. This demonstrates again that, with careful choice of fusion constructs, overlapping structures exhibit very similar conformations for the myosin rod fragments in the canonical regions. However, conformational variability is seen around Leu1706 which is a hot spot for cardiomyopathy mutations suggesting that this might be important for function.

  2. Coil protection calculator for TFTR

    International Nuclear Information System (INIS)

    Marsala, R.J.; Lawson, J.E.; Persing, R.G.; Senko, T.R.; Woolley, R.D.

    1989-01-01

    A new coil protection system (CPS) is being developed to replace the existing TFTR magnetic coil fault detector. The existing fault detector sacrifices TFTR operating capability for simplicity. The new CPS, when installed in October of 1988, will permit operation up to the actual coil stress limits parameters in real-time. The computation will be done in a microprocessor based Coil Protection Calculator (CPC) currently under construction at PPL. THe new CPC will allow TFTR to operate with higher plasma currents and will permit the optimization of pulse repetition rates. The CPC will provide real-time estimates of critical coil and bus temperatures and stresses based on real-time redundant measurements of coil currents, coil cooling water inlet temperature, and plasma current. The critical parameter calculations are compared to prespecified limits. If these limits are reached or exceeded, protection action will be initiated to a hard wired control system (HCS), which will shut down the power supplies. The CPC consists of a redundant VME based microprocessor system which will sample all input data and compute all stress quantities every ten milliseconds. Thermal calculations will be approximated every 10ms with an exact solution occurring every second. The CPC features continuous cross-checking of redundant input signal, automatic detection of internal failure modes, monitoring and recording of calculated results, and a quick, functional verification of performance via an internal test system. (author)

  3. Coil end design for the LHC dipole magnet

    International Nuclear Information System (INIS)

    Brandt, J.S.

    1996-01-01

    This paper describes the design of the coil ends for the Large Hadron Collider dipole magnets of the CERN European Laboratory for Particle Physics in Switzerland. This alternative to existing European designs was provided by Fermi National Accelerator Laboratory by agreement between CERN and the United States. The superconducting cable paths are determined from both magnetic and mechanical considerations. The coil end parts used to shape and constrain the conductors in the coil ends are designed using the developable surface, grouped end approach. This method allows the analysis of strain energy within the conductor groups, and the optimization of mechanical factors during the design. Design intent and implementation are discussed. Inner and outer coil design challenges and end analysis are detailed

  4. Depletion-Mode GaN HEMT Q-Spoil Switches for MRI Coils.

    Science.gov (United States)

    Lu, Jonathan Y; Grafendorfer, Thomas; Zhang, Tao; Vasanawala, Shreyas; Robb, Fraser; Pauly, John M; Scott, Greig C

    2016-12-01

    Q-spoiling is the process of decoupling an MRI receive coil to protect the equipment and patient. Conventionally, Q-spoiling is performed using a PIN diode switch that draws significant current. In this work, a Q-spoiling technique using a depletion-mode Gallium Nitride HEMT device was developed for coil detuning at both 1.5 T and 3 T MRI. The circuits with conventional PIN diode Q-spoiling and the GaN HEMT device were implemented on surface coils. SNR was measured and compared for all surfaces coils. At both 1.5 T and 3 T, comparable SNR was achieved for all coils with the proposed technique and conventional Q-spoiling. The GaN HEMT device has significantly reduced the required power for Q-spoiling. The GaN HEMT device also provides useful safety features by detuning the coil when unpowered.

  5. Coil for LEAR extraction septum

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    Which way does the current flow ? This intriguing object is the coil for the LEAR extraction septum. There were two septa, first a thin one, then this one, not so thin, somewhat on the borderline between septum and bending magnet.

  6. First coil for the SC

    CERN Multimedia

    CERN PhotoLab

    1955-01-01

    The coils for the SC magnet were stored in the large hangar of the Cointrin Airport (to make sure that they would be available before snow and ice would block the roads and canals from Belgium, where they were built).

  7. Radiation resistant ducted superconductive coil

    International Nuclear Information System (INIS)

    Schleich, A.

    1976-01-01

    The radiation-resistant ducted superconductive coil consists of a helically wound electrical conductor constituted by an electrically conductive core of superconductive material provided with a longitudinally extending cooling duct. The core is covered with a layer of inorganic insulating material and the duct is covered by an electrically conductive metallic gas-tight sheath. The metallic sheaths on adjacent turns of the coil are secured together. 2 Claims, 4 Drawing Figures

  8. The Swiss LCT-coil

    International Nuclear Information System (INIS)

    Vecsey, G.; Benz, H.; Horvath, I.

    1985-01-01

    With delivery of the coil to ORNL on February 4, 1984, the second phase of the Swiss Large Coil Program - design and construction - was terminated. Mainlines of the Swiss design concept are summarized and related to theoretical calculations, experimental results of the supporting program, fabricational experience and first successful test results. An attempt is made to draw preliminary conclusions with regard to the design of future toroidal systems such as NET

  9. The SMES model coil. Fabrication

    International Nuclear Information System (INIS)

    Hanai, Satoshi; Nakamoto, Kazunari; Takahashi, Nobuji

    1998-01-01

    A SMES model coil was fabricated as R and D item in the development of component technologies for a 480 MJ/20 MW SMES pilot plant. The coil consists of four double-pancake windings. The coil is the same diameter but half the number of pancakes that will be needed for a SMES pilot plant. The NbTi cable-in-conduit conductor and superconducting joints between the double pancakes are cooled by a forced flow of supercritical helium. Prior to fabrication, various characteristics of the cable-in-conduit were measured by full-sized short samples from actual conductors and by scaled short samples from scaled conductors. The critical current of the scaled short samples was in agreement with that calculated from one strand of the conductor. The impedance between arbitrary dual-oxide coated strands in the full-size conductor was measured to be smaller than that obtained from two Cr-plated strands, which showed a good degree of stability in another coil. It was estimated that oxide-coated conductors would have high stability. Through fabrication of a model coil, it was demonstrated that a large forced-flow coil for a small-scale 100 kWh SMES device could be manufactured. (author)

  10. The SMES model coil. Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Hanai, Satoshi; Nakamoto, Kazunari; Takahashi, Nobuji [Toshiba Corp., Yokohama, Kanagawa (Japan)] [and others

    1998-07-01

    A SMES model coil was fabricated as R and D item in the development of component technologies for a 480 MJ/20 MW SMES pilot plant. The coil consists of four double-pancake windings. The coil is the same diameter but half the number of pancakes that will be needed for a SMES pilot plant. The NbTi cable-in-conduit conductor and superconducting joints between the double pancakes are cooled by a forced flow of supercritical helium. Prior to fabrication, various characteristics of the cable-in-conduit were measured by full-sized short samples from actual conductors and by scaled short samples from scaled conductors. The critical current of the scaled short samples was in agreement with that calculated from one strand of the conductor. The impedance between arbitrary dual-oxide coated strands in the full-size conductor was measured to be smaller than that obtained from two Cr-plated strands, which showed a good degree of stability in another coil. It was estimated that oxide-coated conductors would have high stability. Through fabrication of a model coil, it was demonstrated that a large forced-flow coil for a small-scale 100 kWh SMES device could be manufactured. (author)

  11. Equilibrium field coil concepts for INTOR

    International Nuclear Information System (INIS)

    Strickler, D.J.; Peng, Y.K.M.; Brown, T.G.

    1981-08-01

    Methods are presented for reducing ampere-turn requirements in the EF coil system. It is shown that coil currents in an EF coil system external to the toroidal field coils can be substantially reduced by relaxing the triangularity of a D-shaped plasma. Further reductions are realized through a hybrid EF coil system using both internal and external coils. Equilibrium field coils for a poloidally asymmetric, single-null INTOR configuration are presented. It is shown that the shape of field lines in the plasma scrapeoff region and divertor channel improves as triangularity is reduced, but it does so at the possible expense of achievable stable beta values

  12. Endovascular rescue method for undesirably stretched coil.

    Science.gov (United States)

    Cho, Jae Hoon

    2014-10-01

    Undesirable detachment or stretching of coils within the parent artery during aneurysm embolization can be related with thrombus formation, which can be caused occlusion of parent artery or embolic event(s). To escape from this situation, several rescue methods have been reported. A case with undesirably stretched coil in which another rescue method was used, is presented. When the stretched coil is still located in the coil delivery microcatheter, the stretched coil can be removed safely using a snare and a handmade monorail microcatheter. After a snare is lodged in the handmade monorail microcatheter, the snare is introduced over the coil delivery micorcatheter and located in the distal part of the stretched coil. After then, the handmade monorail microcatheter captures the stretched coil and the snare as one unit. This technique using a handmade monorail microcatheter and a snare can be a good rescue modality for the undesirably stretched coil, still remained within the coil delivery microcatheter.

  13. Redesigning existing transcranial magnetic stimulation coils to reduce energy: application to low field magnetic stimulation

    Science.gov (United States)

    Wang, Boshuo; Shen, Michael R.; Deng, Zhi-De; Smith, J. Evan; Tharayil, Joseph J.; Gurrey, Clement J.; Gomez, Luis J.; Peterchev, Angel V.

    2018-06-01

    Objective. To present a systematic framework and exemplar for the development of a compact and energy-efficient coil that replicates the electric field (E-field) distribution induced by an existing transcranial magnetic stimulation coil. Approach. The E-field generated by a conventional low field magnetic stimulation (LFMS) coil was measured for a spherical head model and simulated in both spherical and realistic head models. Then, using a spherical head model and spatial harmonic decomposition, a spherical-shaped cap coil was synthesized such that its windings conformed to a spherical surface and replicated the E-field on the cortical surface while requiring less energy. A prototype coil was built and electrically characterized. The effect of constraining the windings to the upper half of the head was also explored via an alternative coil design. Main results. The LFMS E-field distribution resembled that of a large double-cone coil, with a peak field strength around 350 mV m‑1 in the cortex. The E-field distributions of the cap coil designs were validated against the original coil, with mean errors of 1%–3%. The cap coil required as little as 2% of the original coil energy and was significantly smaller in size. Significance. The redesigned LFMS coil is substantially smaller and more energy-efficient than the original, improving cost, power consumption, and portability. These improvements could facilitate deployment of LFMS in the clinic and potentially at home. This coil redesign approach can also be applied to other magnetic stimulation paradigms. Finally, the anatomically-accurate E-field simulation of LFMS can be used to interpret clinical LFMS data.

  14. Dynamic multi-channel TMS with reconfigurable coil.

    Science.gov (United States)

    Jiang, Ruoli; Jansen, Ben H; Sheth, Bhavin R; Chen, Ji

    2013-05-01

    Investigations of the causal involvement of particular brain areas and interconnections in behavior require an external stimulation system with reasonable spatio-temporal resolution. Current transcranial magnetic stimulation (TMS) technology is limited to stimulating a single brain area once in a given trial. Here, we present a feasibility study for a novel TMS system based on multi-channel reconfigurable coils. With this hardware, researchers will be able to stimulate multiple brain sites in any temporal order in a trial. The system employs a wire-mesh coil, constructed using x- and y-directional wires. By varying the current direction and/or strength on each wire, we can configure the proposed mesh-wire coil into a standard loop coil and figure-eight coil of varying size. This provides maximum flexibility to the experimenter in that the location and extent of stimulation on the brain surface can be modified depending on experimental requirement. Moreover, one can dynamically and automatically modify the site(s) of stimulation several times within the span of seconds. By pre-storing various sequences of excitation patterns inside a control unit, one can explore the effect of dynamic TMS on behavior, in associative learning, and as rehabilitative therapy. Here, we present a computer simulation and bench experiments that show the feasibility of the dynamically-reconfigurable coil.

  15. Dental MRI using a dedicated RF-coil at 3 Tesla.

    Science.gov (United States)

    Prager, Marcel; Heiland, Sabine; Gareis, Daniel; Hilgenfeld, Tim; Bendszus, Martin; Gaudino, Chiara

    2015-12-01

    To assess the benefit of a dedicated surface coil to visualize dental structures in comparison to standard head/neck coil. Measurements were performed using the standard head/neck coil and a dedicated array coil for dental MRI at 3 T. As MRI methods, we used a T1-weighted spin-echo sequence with and without spectral fat saturation, a T2-weighted turbo-spin-echo sequence and a 3-dimensional T2-weighted SPACE sequence. Measurements were performed in a phantom to examine sensitivity profiles. Then the signal gain in dental structures was examined in volunteers and in a patient. As expected for a surface coil, the signal gain of the dental coil was highest at the surface of the phantom and decreased with increasing distance to the coil; it was >120% even at a depth of 30 mm, measured from the centre of the coil. The signal gain within the pulp of the volunteers ranged between 236 and 413%. The dedicated array coil offers a significantly higher signal within the region of interest for dental MR imaging thus allowing for better depiction of pathologies within the periodontium and for delineation and tracking of the branches of the maxillary and mandibular nerves. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  16. Magnetic resonance imaging of rodent spinal cord with an improved performance coil at 7 Tesla

    Science.gov (United States)

    Solis-Najera, S. E.; Rodriguez, A. O.

    2014-11-01

    Magnetic Resonance Imaging of animal models provide reliable means to study human diseases. The image acquisition particularly determined by the radio frequency coil to detect the signal emanated from a particular region of interest. A scaled-down version of the slotted surface coil was built based on the previous results of a magnetron-type surface coil for human applications. Our coil prototype had a 2 cm total diameter and six circular slots and was developed for murine spinal cord at 7 T. Electromagnetic simulations of the slotted and circular coils were also performed to compute the spatially dependent magnetic and electric fields using a simulated saline-solution sphere. The quality factor of both coils was experimentally measured giving a lower noise figure and a higher quality factor for the slotted coil outperforming the circular coil. Images of the spinal cord of a rat were acquired using standard pulse sequences. The slotted surface coil can be a good tool for spinal cord rat imaging using conventional pulse sequences at 7 T.

  17. Coil supporting device in nuclear fusion apparatus

    International Nuclear Information System (INIS)

    Hoshi, Ryo; Imura, Yasuya.

    1974-01-01

    Object: To secure intermediate fittings with a coil fixed thereon by an insulating tape to a fixed body by means of fittings, thereby supporting the coil in a narrow space. Structure: A coil is secured to intermediate fittings by means of an insulating tape, after which the intermediate fittings is mounted on a fixed body through fittings to support the coil in a narrow clearance portion between a plasma sealed vessel and a main coil. (Kamimura, M.)

  18. Updating the Design of the Poloidal Field Coils for the ITER Magnet System

    International Nuclear Information System (INIS)

    Yoshida, K.; Takahashi, Y.; Mitchell, N.; Jong, C.; Bessette, D.

    2006-01-01

    The ITER superconducting coil system consists of 18 Toroidal Field coils, six Poloidal Field (PF) coils, six Central Solenoid (CS) modules, 18 Correction Coils and their feeders. The six PF coils are attached to the TF coil cases through flexible plates or sliding supports allowing radial displacements. The PF coils and CS modules provide suitable magnetic fields for plasma shaping and position control. The PF coils use NbTi superconductor, cooled by supercritical helium. This gives a substantial cost saving compared to Nb 3 Sn and the elimination of a reaction heat treatment greatly simplifies the insulation of such large diameter coils. The cable configuration is 6 sub-cables arranged around a central cooling space. The conductors have a heavy square walled stainless steel jacket. The latest parameters of conductor design are evaluated by analysis of the minimum quench energy and hotspot temperature. The PF coils are self supporting as regards the radial magnetic loads. The vertical loads on each PF coil are transmitted to the TF coil cases. Load transmission is through flexible plates for the PF2 to PF5 coils or sliding supports for the PF1 and PF6 coils with fibreslip bearing surfaces. The supports for the PF winding consist of a set of clamping plates and stud bolts. The shape of the clamping plates has been designed to minimize stresses in the winding pack insulation. Bolts are pre-tensioned to keep pressure between the winding pack and clamping plate. Because of the difficulties in replacing the PF coils, the most unreliable component (the coil insulation) is designed with extra redundancy. There are two insulation layers with a thin metal screen in between. By monitoring the voltage of the intermediate screen, it is possible to detect an incipient short, defined as a short in only one of the two insulation layers. Adjustment of the screen voltage level may allow the shot growth to the stopped once it is detected. Alternately the faulty double pancake must

  19. A large stellarator based on modular coils

    International Nuclear Information System (INIS)

    Hamberger, S.M.; Sharp, L.E.; Petersen, L.F.

    1979-06-01

    Although stellarators offer some considerable advantages over tokamaks, difficulties arise in designing large devices due, for instance, to poor plasma access as well as to constructional electromechanical and maintenance problems associated with continous helical windings. This paper describes a design for a fairly large device (major radius 2.1m), based on a set of discrete coil modules arranged in a toroidal configuration to provide the required closed magnetic surfaces, having gaps for unobstructed access to the plasma for diagnostics, etc, and allowing for easy removal for maintenance

  20. Kevad Veneetsias / Peeter Pere

    Index Scriptorium Estoniae

    Pere, Peeter, 1957-

    2013-01-01

    Arhitektuuriga haakuvatest töödest 55. Venezia biennaalil. Walter de Maria (USA), Robert Goberi (USA), Andra Ursuta (Rumeenia), Jasper Justi (Taani), Lara Almarcequi (Hispaania) ja Dénes Farkase (Eesti) töödest

  1. Spectroscopy With Surface Coils and Decoupling

    Science.gov (United States)

    2015-12-23

    Adrenal Cortical Cancer; Brain Cancer; Breast Cancer; CNS Cancer; Colon Cancer; HEENT Cancer; Hodgkin's Disease; Kaposi's Sarcoma; Liver Cancer; Lung Cancer; Non-Hodgkin's Lymphoma; Ovarian Cancer; Pancreatic Cancer; Prostate Cancer; Rectal Cancer; Renal Cancer; Sarcoma; Squamous Cell Carcinoma; Thyroid Cancer

  2. BI-ground microstrip array coil vs. conventional microstrip array coil for mouse imaging at 7 tesla

    Science.gov (United States)

    Hernández, Ricardo; Terrones, M. A. López; Jakob, P. M.

    2012-10-01

    At high field strengths, the need for more efficient high frequency coils has grown. Since the radiation losses and the interaction between coil and sample increase proportionally to field strength, the quality factor (Q) and the sensitivity of the coil decrease as consequence of these negative effects. Since Zhang et al proposed in 2001 a new surface coil based on the microstrip transmission line for high frequency, different Tx-Rx phased arrays based on this concept have been already introduced in animal and whole body systems at high field strengths, each of them with different modifications in order to get better field homogeneity, SNR or isolation between coil elements in the array. All these arrays for animals systems have been built for rat imaging. One of these modifications is called BI-Ground Microstrip Array Coil (BIGMAC). The implementation of a smaller two-channel BIGMAC design for mouse imaging is studied and its performance compared to a two-channel conventional Microstrip array at 7 Tesla, the higher isolation by using BIGMAC elements in comparison with conventional Microstrip elements is shown in this work.

  3. Structural basis for cargo binding and autoinhibition of Bicaudal-D1 by a parallel coiled-coil with homotypic registry

    Energy Technology Data Exchange (ETDEWEB)

    Terawaki, Shin-ichi, E-mail: terawaki@gunma-u.ac.jp [Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikane, Asuka [Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Higuchi, Yoshiki [Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan); Department of Picobiology, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan); SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Wakamatsu, Kaori [Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); SPring-8 Center, RIKEN, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

    2015-05-01

    Bicaudal-D1 (BICD1) is an α-helical coiled-coil protein mediating the attachment of specific cargo to cytoplasmic dynein. It plays an essential role in minus end-directed intracellular transport along microtubules. The third C-terminal coiled-coil region of BICD1 (BICD1 CC3) has an important role in cargo sorting, including intracellular vesicles associating with the small GTPase Rab6 and the nuclear pore complex Ran binding protein 2 (RanBP2), and inhibiting the association with cytoplasmic dynein by binding to the first N-terminal coiled-coil region (CC1). The crystal structure of BICD1 CC3 revealed a parallel homodimeric coiled-coil with asymmetry and complementary knobs-into-holes interactions, differing from Drosophila BicD CC3. Furthermore, our binding study indicated that BICD1 CC3 possesses a binding surface for two distinct cargos, Rab6 and RanBP2, and that the CC1-binding site overlaps with the Rab6-binding site. These findings suggest a molecular basis for cargo recognition and autoinhibition of BICD proteins during dynein-dependent intracellular retrograde transport. - Highlights: • BICD1 CC3 is a parallel homodimeric coiled-coil with axial asymmetry. • The coiled-coil packing of BICD1 CC3 is adapted to the equivalent heptad position. • BICD1 CC3 has distinct binding sites for two classes of cargo, Rab6 and RanBP2. • The CC1-binding site of BICD1 CC3 overlaps with the Rab6-binding site.

  4. Structural basis for cargo binding and autoinhibition of Bicaudal-D1 by a parallel coiled-coil with homotypic registry

    International Nuclear Information System (INIS)

    Terawaki, Shin-ichi; Yoshikane, Asuka; Higuchi, Yoshiki; Wakamatsu, Kaori

    2015-01-01

    Bicaudal-D1 (BICD1) is an α-helical coiled-coil protein mediating the attachment of specific cargo to cytoplasmic dynein. It plays an essential role in minus end-directed intracellular transport along microtubules. The third C-terminal coiled-coil region of BICD1 (BICD1 CC3) has an important role in cargo sorting, including intracellular vesicles associating with the small GTPase Rab6 and the nuclear pore complex Ran binding protein 2 (RanBP2), and inhibiting the association with cytoplasmic dynein by binding to the first N-terminal coiled-coil region (CC1). The crystal structure of BICD1 CC3 revealed a parallel homodimeric coiled-coil with asymmetry and complementary knobs-into-holes interactions, differing from Drosophila BicD CC3. Furthermore, our binding study indicated that BICD1 CC3 possesses a binding surface for two distinct cargos, Rab6 and RanBP2, and that the CC1-binding site overlaps with the Rab6-binding site. These findings suggest a molecular basis for cargo recognition and autoinhibition of BICD proteins during dynein-dependent intracellular retrograde transport. - Highlights: • BICD1 CC3 is a parallel homodimeric coiled-coil with axial asymmetry. • The coiled-coil packing of BICD1 CC3 is adapted to the equivalent heptad position. • BICD1 CC3 has distinct binding sites for two classes of cargo, Rab6 and RanBP2. • The CC1-binding site of BICD1 CC3 overlaps with the Rab6-binding site

  5. Effect of reduction of mechanical losses in AC superconducting coils having various FRP bobbins

    International Nuclear Information System (INIS)

    Sekine, N.; Tada, S.; Higuchi, T.; Takao, T.; Yamanaka, A.; Fukui, S.

    2004-01-01

    We have demonstrated in our previous works that a use of the particular structural material for superconducting coils was effective to mechanical-loss reduction under AC operation. In this study, we measured losses to investigate influence of the mechanical losses in the coils having various fiber reinforced plastics (FRPs) with different thermal expansion coefficients. The losses were small in the coils whose winding tension at coil-operating temperature were strong, on the contrary, the losses of the coil having the weak winding tension were large. The coil having the strongest winding tension at liquid helium temperature showed the smallest loss in all coils, and the loss agreed with a value from the Norris's analysis. We think that the mechanical loss becomes almost zero in this coil since the strong tension can prevent the periodic vibration of the superconducting wire. The dependence of the loss on the difference in surface conditions of the materials of the superconducting coil's bobbins was not observed, however, the mechanical losses in AC coils strongly depended on the winding tensions at cryogenic temperature

  6. Free-boundary Full-pressure Island Healing in a Stellarator: Coil-healing

    International Nuclear Information System (INIS)

    Hudson, S.R.; Reiman, A.; Strickler, D.; Brooks, A.; Monticello, D.A.; Hirshman, S.P.

    2002-01-01

    The lack of axisymmetry in stellarators guarantees that in general magnetic islands and chaotic magnetic field lines will exist. As particle transport is strongly tied to the magnetic field lines, magnetic islands and chaotic field lines result in poor plasma confinement. For stellarators to be feasible candidates for fusion power stations it is essential that, to a good approximation, the magnetic field lines lie on nested flux-surfaces, and the suppression of magnetic islands is a critical issue for stellarator coil design, particularly for small aspect ratio devices. A procedure for modifying stellarator coil designs to eliminate magnetic islands in free-boundary full-pressure magnetohydrodynamic equilibria is presented. Islands may be removed from coil-plasma free-boundary equilibria by making small changes to the coil geometry and also by variation of trim coil currents. A plasma and coil design relevant to the National Compact Stellarator Experiment is used to illustrate the technique

  7. Hessian matrix approach for determining error field sensitivity to coil deviations

    Science.gov (United States)

    Zhu, Caoxiang; Hudson, Stuart R.; Lazerson, Samuel A.; Song, Yuntao; Wan, Yuanxi

    2018-05-01

    The presence of error fields has been shown to degrade plasma confinement and drive instabilities. Error fields can arise from many sources, but are predominantly attributed to deviations in the coil geometry. In this paper, we introduce a Hessian matrix approach for determining error field sensitivity to coil deviations. A primary cost function used for designing stellarator coils, the surface integral of normalized normal field errors, was adopted to evaluate the deviation of the generated magnetic field from the desired magnetic field. The FOCUS code (Zhu et al 2018 Nucl. Fusion 58 016008) is utilized to provide fast and accurate calculations of the Hessian. The sensitivities of error fields to coil displacements are then determined by the eigenvalues of the Hessian matrix. A proof-of-principle example is given on a CNT-like configuration. We anticipate that this new method could provide information to avoid dominant coil misalignments and simplify coil designs for stellarators.

  8. Pulsed-Field Magnetization Properties of Bulk Superconductors by Employment of Vortex-Type Coils

    Science.gov (United States)

    Deng, Z.; Shinohara, N.; Miki, M.; Felder, B.; Tsuzuki, K.; Watasaki, M.; Kawabe, S.; Taguchi, R.; Izumi, M.

    Vortex-type magnetizing coils are gaining more and more attention to activate bulk superconductors in pulsed-field magnetization (PFM) studies, compared with solenoid-type ones. Following existing reports, we present experimental results of the different penetration patterns of magnetic flux between the two kinds of coils. It was found that the magnetic flux will primarily penetrate inside the bulk from the upper and lower surfaces by using vortex coils, rather than from the periphery in the case of solenoid coils. Moreover, the bulk submitted to a small pulsed-field excitation exhibits a similar field profile as the excitation field (convex or concave shape); a phenomenon named field memory effect. The use of vortex- or solenoid-type coils in PFM will pose an influence on the initial flux penetration patterns during the flux trapping processes, but both coils can finally excite the best conical trapped field shape of the bulk.

  9. Design of a coil sensor for time domain electromagnetic system for uranium exploration

    International Nuclear Information System (INIS)

    Keshwani, R.T.; Bhattacharya, S.

    2011-01-01

    Time domain electromagnetic system is used for exploration of deep seated deposits under the Earth surface. The basic principle is to set up eddy currents in conductors using pulsed excited transmitter coil during on time of a pulse. The decay time of eddy currents during off time of a pulse is a function conductivity, permeability and depth of conductor located under the Earth surface. The technology is being developed to carry out exploration of mineral deposits (basically uranium) under the Earth surface. The decay of eddy currents is eddy using J coil sensor located coplanar with the transmitter coil. The depth upto which successful exploration can be carried is strong function of design of receiver coil. The design parameters include number of turns, bandwidth, stray capacitance and resistance of a coil. This paper describes various designs tried out and their characterization results. Field results for a ground based system developed are also described. (author)

  10. CCHMM_PROF: a HMM-based coiled-coil predictor with evolutionary information

    DEFF Research Database (Denmark)

    Bartoli, Lisa; Fariselli, Piero; Krogh, Anders

    2009-01-01

    tools are available for predicting coiled-coil domains in protein sequences, including those based on position-specific score matrices and machine learning methods. RESULTS: In this article, we introduce a hidden Markov model (CCHMM_PROF) that exploits the information contained in multiple sequence...... alignments (profiles) to predict coiled-coil regions. The new method discriminates coiled-coil sequences with an accuracy of 97% and achieves a true positive rate of 79% with only 1% of false positives. Furthermore, when predicting the location of coiled-coil segments in protein sequences, the method reaches...

  11. Transient voltage oscillations in coils

    International Nuclear Information System (INIS)

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated

  12. Large coil program support structure conceptual design

    International Nuclear Information System (INIS)

    Litherland, P.S.

    1977-01-01

    The purpose of the Large Coil Program (LCP) is to perform tests on both pool boiling and force cooled superconducting toroidal field coils. The tests will attempt to approximate conditions anticipated in an ignition tokamak. The test requirements resulted in a coil support design which accommodates up to six (6) test coils and is mounted to a structure capable of resisting coil interactions. The steps leading to the present LCP coil support structure design, details on selected structural components, and the basic assembly sequence are discussed

  13. Cooling device of superconducting coils

    International Nuclear Information System (INIS)

    Duthil, R.; Lottin, J.C.

    1985-01-01

    This device is rotating around an horizontal axis. The superconducting coils are contained in a cryogenic enclosure feeded in liquid helium forced circulation. They are related to an electric generator by electric mains each of them comprising a gas exchanger, and an exchanger-evaporator set between the cryogenic device and those exchangers. The exchanger-evaporator is aimed at dissipating the heat arriving by conductors connected to the superconducting coils. According to the invention, the invention includes an annular canalization with horizontal axis in which the connection conductors bathe in liquid helium [fr

  14. A 2-in-1 single-element coil design for transcranial magnetic stimulation and magnetic resonance imaging.

    Science.gov (United States)

    Lu, Hai; Wang, Shumin

    2018-01-01

    To demonstrate the feasibility of turning transcranial magnetic stimulation (TMS) coil for MRI signal reception. A critically coupled network was formed by using a resonated turn of TMS coil as the secondary and a regular radiofrequency (RF) coil as the primary. A third coil was positioned between the two coils for detuning during RF transmission. Bench measurement, numerical simulation, and MRI experiment were performed for validation. The signal-to-noise ratio of the proposed 2-in-1 coil is 35% higher in its field of view, compared with a MRI-only reference coil of the same size, made by the same material, and backed up by an untuned TMS coil, but lower than a RF surface coil of the same size without any TMS coil nearby. Spin-echo images of the human brain further validated its performance. The proposed method can transform TMS coil for MRI signal acquisition with virtually no modifications on the TMS side. It not only enables flexible and close positioning of TMS coil inside MRI scanner, but also improves the signal-to-noise ratio compared with conventional implementations. It can be applied as a building block for developing advanced concurrent TMS/MRI hardware. Magn Reson Med 79:582-587, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  15. Feasibility and repeatability of localized (31) P-MRS four-angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T.

    Science.gov (United States)

    Tušek Jelenc, Marjeta; Chmelík, Marek; Bogner, Wolfgang; Krššák, Martin; Trattnig, Siegfried; Valkovič, Ladislav

    2016-01-01

    Phosphorus ((31) P) MRS, combined with saturation transfer (ST), provides non-invasive insight into muscle energy metabolism. However, even at 7 T, the standard ST method with T1 (app) measured by inversion recovery takes about 10 min, making it impractical for dynamic examinations. An alternative method, i.e. four-angle saturation transfer (FAST), can shorten the examination time. The aim of this study was to test the feasibility, repeatability, and possible time resolution of the localized FAST technique measurement on an ultra-high-field MR system, to accelerate the measurement of both Pi -to-ATP and PCr-to-ATP reaction rates in the human gastrocnemius muscle and to test the feasibility of using the FAST method for dynamic measurements. We measured the exchange rates and metabolic fluxes in the gastrocnemius muscle of eight healthy subjects at 7 T with the depth-resolved surface coil MRS (DRESS)-localized FAST method. For comparison, a standard ST localized method was also used. The measurement time for the localized FAST experiment was 3.5 min compared with the 10 min for the standard localized ST experiment. In addition, in five healthy volunteers, Pi -to-ATP and PCr-to-ATP metabolic fluxes were measured in the gastrocnemius muscle at rest and during plantar flexion by the DRESS-localized FAST method. The repeatability of PCr-to-ATP and Pi -to-ATP exchange rate constants, determined by the slab-selective localized FAST method at 7 T, is high, as the coefficients of variation remained below 20%, and the results of the exchange rates measured with the FAST method are comparable to those measured with standard ST. During physical activity, the PCr-to-ATP metabolic flux decreased (from FCK  = 8.21 ± 1.15 mM s(-1) to FCK  = 3.86 ± 1.38 mM s(-1) ) and the Pi -to-ATP flux increased (from FATP  = 0.43 ± 0.14 mM s(-1) to FATP  = 0.74 ± 0.13 mM s(-1) ). In conclusion, we could demonstrate that measurements

  16. Large Coil Program magnetic system design study

    International Nuclear Information System (INIS)

    Moses, S.D.; Johnson, N.E.

    1977-01-01

    The primary objective of the Large Coil Program (LCP) is to demonstrate the reliable operation of large superconducting coils to provide a basis for the design principles, materials, and fabrication techniques proposed for the toroidal magnets for the THE NEXT STEP (TNS) and other future tokamak devices. This paper documents a design study of the Large Coil Test Facility (LCTF) in which the structural response of the Toroidal Field (TF) Coils and the supporting structure was evaluated under simulated reactor conditions. The LCP test facility structural system consists of six TF Coils, twelve coil-to-coil torsional restraining beams (torque rings), a central bucking post with base, and a Pulse Coil system. The NASTRAN Finite Element Structural Analysis computer Code was utilized to determine the distribution of deflections, forces, and stresses for each of the TF Coils, torque rings, and the central bucking post. Eleven load conditions were selected to represent probable test operations. Pulse Coils suspended in the bore of the test coil were energized to simulate the pulsed field environment characteristic of the TNS reactor system. The TORMAC Computer Code was utilized to develop the magnetic forces in the TF Coils for each of the eleven loading conditions examined, with or without the Pulse Coils energized. The TORMAC computer program output forces were used directly as input load conditions for the NASTRAN analyses. Results are presented which demonstrate the reliability of the LCTF under simulated reactor operating conditions

  17. In vivo field-cycling relaxometry using an insert coil for magnetic field offset.

    Science.gov (United States)

    Pine, Kerrin J; Goldie, Fred; Lurie, David J

    2014-11-01

    The T(1) of tissue has a strong dependence on the measurement magnetic field strength. T(1) -dispersion could be a useful contrast parameter, but is unavailable to clinical MR systems which operate at fixed magnetic field strength. The purpose of this work was to implement a removable insert magnet coil for field-cycling T(1) -dispersion measurements on a vertical-field MRI scanner, by offsetting the static field over a volume of interest. An insert magnet coil was constructed for use with a whole-body sized 59 milli-Tesla (mT) vertical-field, permanent-magnet based imager. The coil has diameter 38 cm and thickness 6.1 cm and a homogeneous region (± 5%) of 5 cm DSV, offset by 5 cm from the coil surface. Surface radiofrequency (RF) coils were also constructed. The insert coil was used in conjunction with a surface RF coil and a volume-localized inversion-recovery pulse sequence to plot T(1) -dispersion in a human volunteer's forearm over a range of field strengths from 1 mT to 70 mT. T(1) -dispersion measurements were demonstrated on a fixed-field MRI scanner, using an insert coil. This demonstrates the feasibility of relaxation dispersion measurements on an otherwise conventional MR imager, facilitating the exploitation of T(1) -dispersion contrast for enhanced diagnosis. Copyright © 2013 Wiley Periodicals, Inc.

  18. Finite element coiled cochlea model

    Science.gov (United States)

    Isailovic, Velibor; Nikolic, Milica; Milosevic, Zarko; Saveljic, Igor; Nikolic, Dalibor; Radovic, Milos; Filipović, Nenad

    2015-12-01

    Cochlea is important part of the hearing system, and thanks to special structure converts external sound waves into neural impulses which go to the brain. Shape of the cochlea is like snail, so geometry of the cochlea model is complex. The simplified cochlea coiled model was developed using finite element method inside SIFEM FP7 project. Software application is created on the way that user can prescribe set of the parameters for spiral cochlea, as well as material properties and boundary conditions to the model. Several mathematical models were tested. The acoustic wave equation for describing fluid in the cochlea chambers - scala vestibuli and scala timpani, and Newtonian dynamics for describing vibrations of the basilar membrane are used. The mechanical behavior of the coiled cochlea was analyzed and the third chamber, scala media, was not modeled because it does not have a significant impact on the mechanical vibrations of the basilar membrane. The obtained results are in good agreement with experimental measurements. Future work is needed for more realistic geometry model. Coiled model of the cochlea was created and results are compared with initial simplified coiled model of the cochlea.

  19. BPX toroidal field coil design

    International Nuclear Information System (INIS)

    Heitzenvoeder, D.J.

    1992-01-01

    This paper reports on the toroidal field (TF) coil system of the Burning Plasma Experiment (BPX) which consists of (18) beryllium copper magnets arrayed in a wedged configuration with a major radius of 2.6 meters and a field strength capability on axis of 9.0 Tesla. The toroidal array is constructed from six (3)-coil modules to facilitate remote recovery in the event of a magnet failure after nuclear activation precludes hands-on servicing. The magnets are of a modified Bitter plate design with partial cases of type 316-LN stainless steel welded with Inconel 182 weld wire. The coil turn plates are fabricated from CDA C17510 beryllium copper with optimized mechanical, thermal, and electrical characteristics. joints within the turns and between turns are made by welding with C17200 filler wire. Cryogenic cooling is employed to reduce power dissipation and to enhance performance. The magnets are cooled between experimental pulses by pressurized liquid nitrogen flowing through channels in the edges of the coil turns. This arrangement makes possible one full-power pulse per hour. Electrical insulation consists of polyimide-glass sheets bonded in place with vacuum-pressure impregnated epoxy/glass

  20. Demonstration poloidal coil test facility

    International Nuclear Information System (INIS)

    Sato, Masahiko; Kawano, Katumi; Tada, Eisuke

    1989-01-01

    A new compact cryogenic cold compressor was developed by Japan Atomic Energy Research Institute (JAERI) in collaboration with Isikawajima-Harima Heavy Industries Co., Ltd. (IHI) in order to produce the supercritical helium below 4.2 K for Demonstration Poloidal Coils (DPC) which are forced-flow cooled type superconducting pulse coils. This compressor is one of key components for DPC test facility. The cold compressor reduces pressure in liquid helium bath, which contains liquid helium of around 3,000 l, down to 0.5 atm efficiently. Consequently, supercritical helium down to 3.5 K is produced and supplied to the DPC coils. A centrifugal compressor with dynamic gas bearing is selected as a compressor mechanism to realize high adiabatic efficiency and large flow rate. In this performance tests, the compressor was operated for 220 h at saturated condition from 0.5 to 1.0 atm without any failure. High adiabatic efficiency (more than 60 %) is achieved with wide flow range (25-65 g/s) and the design value is fully satisfied. The compressor can rotate up to 80,000 rpm at maximum then the coil supply temperature of supercritical helium is 3.5 K. (author)

  1. Open-Coil Retraction Spring

    Directory of Open Access Journals (Sweden)

    Pavankumar Janardan Vibhute

    2011-01-01

    Full Text Available Sliding mechanic has become a popular method for space closure with developments in preadjusted edgewise appliance. Furthermore, various space closing auxiliaries have been developed and evaluated extensively for their clinical efficiency. Their effectiveness enhanced with optimum force magnitude and low-load deflection rate (LDR/force decay. With the advent of NiTi springs in orthodontics, LDRs have been markedly reduced. For use of NiTi, clinician has to depend upon prefabricated closed coil springs. “Open Coil Retraction Spring (OCRS” is developed utilizing NiTi open-coil spring for orthodontic space closure. This paper describes fabrication and clinical application of OCRS which have number of advantages. It sustains low LDR with optimum force magnitude. Its design is adjustable for desired length and force level. It is fail-safe for both activation and deactivation (i.e., it cannot be over activated, and decompression limit of open coil is also controlled by the operator, resp.. A possibility to offset the OCRS away from mucosa helps to reduce its soft-tissue impingement.

  2. PDX toroidal field coils stress analysis

    International Nuclear Information System (INIS)

    Nikodem, Z.D.; Smith, R.A.

    1975-01-01

    A method used in the stress analysis of the PDX toroidal field coil is developed. A multilayer coil design of arbitrary dimensions in the shape of either a circle or an oval is considered. The analytical model of the coil and the supporting coil case with connections to the main support structure is analyzed using the finite element technique. The three dimensional magnetic fields and the non-uniform body forces which are a loading condition on a coil due to toroidal and poloidal fields are calculated. The method of analysis permits rapid and economic evaluations of design changes in coil geometry as well as in coil support structures. Some results pertinent to the design evolution and their comparison are discussed. The results of the detailed stress analysis of the final coil design due to toroidal field, poloidal field and temperature loads are presented

  3. Miniature coils for producing pulsed inplane magnetic fields for nanospintronics

    Energy Technology Data Exchange (ETDEWEB)

    Pawliszak, Łukasz; Zgirski, Maciej [Institute of Physics, Polish Academy of Sciences, al.Lotnikow 32/46, PL 02-668 Warszawa (Poland); Tekielak, Maria [Faculty of Physics, University of Białystok, ul.Lipowa 41, PL 15-424 Białystok (Poland)

    2015-03-15

    Nanospintronic and related research often requires the application of quickly rising magnetic field pulses in the plane of the studied planar structure. We have designed and fabricated sub-millimeter-sized coils capable of delivering pulses of the magnetic field up to ∼500 Oe in the plane of the sample with the rise time of the order of 10 ns. The placement of the sample above the coil allows for easy access to its surface with manipulators or light beams for, e.g., Kerr microscopy. We use the fabricated coil to drive magnetic domain walls in 1 μm wide permalloy wires and measure magnetic domain wall velocity as a function of the applied magnetic field.

  4. Novel TMS coils designed using an inverse boundary element method

    Science.gov (United States)

    Cobos Sánchez, Clemente; María Guerrero Rodriguez, Jose; Quirós Olozábal, Ángel; Blanco-Navarro, David

    2017-01-01

    In this work, a new method to design TMS coils is presented. It is based on the inclusion of the concept of stream function of a quasi-static electric current into a boundary element method. The proposed TMS coil design approach is a powerful technique to produce stimulators of arbitrary shape, and remarkably versatile as it permits the prototyping of many different performance requirements and constraints. To illustrate the power of this approach, it has been used for the design of TMS coils wound on rectangular flat, spherical and hemispherical surfaces, subjected to different constraints, such as minimum stored magnetic energy or power dissipation. The performances of such coils have been additionally described; and the torque experienced by each stimulator in the presence of a main magnetic static field have theoretically found in order to study the prospect of using them to perform TMS and fMRI concurrently. The obtained results show that described method is an efficient tool for the design of TMS stimulators, which can be applied to a wide range of coil geometries and performance requirements.

  5. Bow-shaped toroidal field coils

    International Nuclear Information System (INIS)

    Bonanos, P.

    1981-05-01

    Design features of Bow-Shaped Toroidal Field Coils are described and compared with circular and D shaped coils. The results indicate that bow coils can produce higher field strengths, store more energy and be made demountable. The design offers the potential for the production of ultrahigh toroidal fields. Included are representative coil shapes and their engineering properties, a suggested structural design and an analysis of a specific case

  6. Design and modelling of a SMES coil

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Weijia; Campbell, A M; Coombs, T A, E-mail: wy215@cam.ac.u [EPEC Superconductivity group, Engineering Department, 9 JJ Thomson Avenue, Cambridge, CB3 0FA (United Kingdom)

    2010-06-01

    The design of a Superconducting Magnetic Energy Storage (SMES) coil wound by coated conductors has been presented. Based on an existing model for coated conductor pancake coils, this paper analysed the magnetic field and current density distribution of the coil at two different operation temperatures, 77K and 22K. A comparison table of the critical currents and AC losses at these two temperatures has been presented. Several steps to improve the transport current of the coil have been suggested as well.

  7. A miniature implantable coil that can be wrapped around a tubular organ within the human body

    Science.gov (United States)

    Mao, Shitong; Wang, Hao; Mao, Zhi-Hong; Sun, Mingui

    2018-05-01

    There are many tubular or rod-shaped organs and tissues within the human body. A miniature medical implant that wraps around such a biological structure can monitor or modulate its function. In order to provide the wrap-around implant with power, a solenoidal coil coupled wirelessly with a planar coil outside the human body can be used. Unfortunately, there is a serious practical problem that this configuration cannot be realized easily because the implantable solenoidal coil cannot be positioned around the tubular biological structure unless either the structure or the coil is cut and reconnected, which is impermissible in most cases. In addition, when a planner exterior coil is used for wireless power transfer and communication, its maximum magnetic coupling with the implanted solenoidal coil is achieved when the tubular structure is perpendicular to the surface of the body. However, in human anatomy, most tubular/rod structures are oriented horizontally. In order to solve these problems, we present a new flexible coil for the class of wrapped-around implantable devices. Our multilayer coil has specially designed windings in cross patterns. The new coil can be made conveniently in high precision at low cost on a flat substrate using the same technology for making the flexible multilayer printed circuit boards along with miniature sensors and electronic circuits. This allows the implant to be made in a flat form and then wrapped around the biostructure during surgery. We present the design of this new coil, perform theoretical analysis with respect to its wireless power transfer efficiency, discuss the effects of coil parameters, and conduct experiments using constructed miniature prototypes. Our results confirm the validity of the new coil.

  8. Suppression of m = 0 in a RFP by toroidal field coils

    International Nuclear Information System (INIS)

    Alexander, D.; Robertson, S.

    1993-01-01

    The Reversatron RFP is normally operated with the toroidal field coils connected in series. The time-integrated voltage applied to the circuit determines the sum of the fluxes linking each turn but not the flux within each turn. Each winding may have a different flux determined by the external drive and by currents within the plasma. A parallel connection of the field coils results in the flux within each coil being determined by the volt-seconds applied to the windings; thus the toroidal flux is the same within each coil. This configuration suppresses any toroidal variation in the toroidal flux and effectively reduces the level of the m = 0 component of the radial field. The m = 0 fluctuations are expected to arise due to nonlinear coupling of the m = 1 modes. A parallel connection of field coils is impractical due to the low impedance required for driving the coils. The authors have tested the effect of parallel connected coils by adding an auxiliary set of 36 coils. These are connected in parallel but are not connected to any supply. The toroidal flux is generated by the series-connected coils which generate voltage but not current in the parallel-connected coils. With the auxiliary coils, the discharge duration is increased from 500 to 550 μsec, the plasma current is increased from 50 kA to 60 kA, F is more negative, Θ is larger, and there is less shot-to-shot variation in the discharges. The m = 0 fluctuations measured by 43 surface coils are, however, only slightly reduced

  9. A miniature implantable coil that can be wrapped around a tubular organ within the human body

    Directory of Open Access Journals (Sweden)

    Shitong Mao

    2018-05-01

    Full Text Available There are many tubular or rod-shaped organs and tissues within the human body. A miniature medical implant that wraps around such a biological structure can monitor or modulate its function. In order to provide the wrap-around implant with power, a solenoidal coil coupled wirelessly with a planar coil outside the human body can be used. Unfortunately, there is a serious practical problem that this configuration cannot be realized easily because the implantable solenoidal coil cannot be positioned around the tubular biological structure unless either the structure or the coil is cut and reconnected, which is impermissible in most cases. In addition, when a planner exterior coil is used for wireless power transfer and communication, its maximum magnetic coupling with the implanted solenoidal coil is achieved when the tubular structure is perpendicular to the surface of the body. However, in human anatomy, most tubular/rod structures are oriented horizontally. In order to solve these problems, we present a new flexible coil for the class of wrapped-around implantable devices. Our multilayer coil has specially designed windings in cross patterns. The new coil can be made conveniently in high precision at low cost on a flat substrate using the same technology for making the flexible multilayer printed circuit boards along with miniature sensors and electronic circuits. This allows the implant to be made in a flat form and then wrapped around the biostructure during surgery. We present the design of this new coil, perform theoretical analysis with respect to its wireless power transfer efficiency, discuss the effects of coil parameters, and conduct experiments using constructed miniature prototypes. Our results confirm the validity of the new coil.

  10. Plasmodium vivax antigen discovery based on alpha-helical coiled coil protein motif

    DEFF Research Database (Denmark)

    Céspedes, Nora; Habel, Catherine; Lopez-Perez, Mary

    2014-01-01

    Protein α-helical coiled coil structures that elicit antibody responses, which block critical functions of medically important microorganisms, represent a means for vaccine development. By using bioinformatics algorithms, a total of 50 antigens with α-helical coiled coil motifs orthologous to Pla...

  11. Sensitive quench detection of the HTS coil using a co-winding coil

    International Nuclear Information System (INIS)

    Takagi, Tomohiro; Ariyama, Takahiro; Takao, Tomoaki; Tsukamoto, Osami

    2017-01-01

    The authors have studied the co-winding coil method (CW method) using the co-wound coil electrically insulated from the HTS coil. In this method, the quench is detected by the voltage difference between the coil of the HTS tape (HTS coil) and the coil of the normal conductor (CW coil). The voltage induced in the CW coil caused by the change of the magnetic field is almost the same as that in the HTS coil because the coils are magnetically coupled close to each other. Therefore, it is expected that the induced voltage will be canceled with high accuracy and that the resistive voltage in the HTS coil will be detected with greater sensitivity compared to the bridge balance method, which is used commonly. In this study, quench detection applying the CW method is demonstrated using an experimental double-pancake coil. A tape with the copper layer deposited on the polymer substrate was used as the insulated conductor wire to form the CW coil. An additional pancake coil was used to expose the experimental double-pancake coil to the external magnetic field asymmetrically. It was shown that the CW method can detect the resistive voltage with greater sensitivity even when the HTS coil was exposed to the changing asymmetric external magnetic field. (author)

  12. Status of the Swiss LCT-coil

    International Nuclear Information System (INIS)

    Zichy, J; Benz, H.; Horvath, I.; Jakob, B.; Marinucci, C.; Vecsey, G.; Weymuth, P.; Zellweger, J.

    1983-01-01

    The Swiss coil is a forced flow coil cooled by supercritical helium. A brief review of the design considerations, some of its specific features, and the progress in fabrication are described. A discussion of both the instrumentation and the cryogenic characteristics of the coil is presented

  13. Linear motor coil assembly and linear motor

    NARCIS (Netherlands)

    2009-01-01

    An ironless linear motor (5) comprising a magnet track (53) and a coil assembly (50) operating in cooperation with said magnet track (53) and having a plurality of concentrated multi-turn coils (31 a-f, 41 a-d, 51 a-k), wherein the end windings (31E) of the coils (31 a-f, 41 a-e) are substantially

  14. Split Coil Forms for Rotary Transformers

    Science.gov (United States)

    Mclyman, C. W. T.

    1982-01-01

    Split cores for rotor and stator windings of rotary transformer mounted around their respective coils (which are in bobbins) and cemented together. This arrangement simplifies winding of stator coil to go in a slot in inner diameter of stator coil. One practical application of rotary transformers fabricated according to this technique is for centrifuges, in which conventional sliprings are of uncertain reliability.

  15. Startup of large coil test facility

    International Nuclear Information System (INIS)

    Haubenreich, P.N.; Bohanan, R.E.; Fietz, W.A.; Luton, J.N.; May, J.R.

    1984-01-01

    The Large Coil Test Facility (LCTF) is being used to test superconducting toroidal field coils about one-third the size of those for INTOR. Data were obtained on performance of refrigerator, helium distribution, power supplies, controls, and data acquisition systems and on the acoustic emission, voltages, currents, and mechanical strains during charging and discharging the coils. (author)

  16. Novel method of aligning ATF-1 coils

    International Nuclear Information System (INIS)

    Rome, J.A.; Harris, J.H.; Neilson, G.H.; Jernigan, T.C.

    1983-08-01

    The coils for the Advanced Toroidal Facility (ATF-1) torsatron may be easily aligned before the machine is placed under vacuum. This is done by creating nulls in the magnetic field by energizing the coils in various configurations. All of the nulls in vertical bar B vector vertical bar occur on the z-axis. When the nulls coincide, the coils are properly aligned

  17. MRI with microscopy coil of the proximal interphalangeal joints: preliminary study

    International Nuclear Information System (INIS)

    Liu Min; Sun Haixing; Liu Dimin; Hu Meiyu; Pan Shunping; Wang Ping; Huang Xiaoling; Men Quanfei; Chen Yingming

    2009-01-01

    Objective: To investigate the use of a microscopy coil in MR examination of proximal interphalangeal joints (PIJ) to collect evidence on micro-anatomical pathological changes for further MR diagnosis. Methods: Four PIJ in cadaver and 12 PIJ from 7 normal volunteers were scanned with a microscopy surface coil (23 mm in diameter) at 1.5 T MRI. Sagittal T 1 -weighted images were also obtained with a conventional surface coil using the same parameters for the volunteers. Based on the observation of sagittal, traverse, coronal PIJ imaging features of cadaver, the optimized sequences were chosen for the volunteer's application. Image quality of the PIJ structures from volunteers was analyzed by two radiologists on a 5-point scale (0, nonvisualization; 1, poor; 2, average; 3, good; 4, excellent) and compared with Wilcoxon signed tank test between the microscopy and C3 surface coil in sagittal direction. Results: With microscopy coil all sequences can visualize the main structures of PI J, and all the PIJ images were classified as good or excellent except for one as average, while all the 12 PIJ with C3 coil were classified as poor or invisible. PIJ structures (proximal phalanx head, middle phalanx base, cartilage, volar plate) from volunteers show higher scores of quality with microscopy coils than those with C3 coil, and the difference was significant (Z =-3.274, -3.274, -3.213, and -3.742 respectively, all P<0.01). Conclusion: High-resolution MRI of the normal PIJ with microscopy coil was superior to those with a conventional surface coil, and it can be a promising method to diagnose interphalangeal joints lesions. (authors)

  18. Self-Assembly of Rod-Coil Block Copolymers

    National Research Council Canada - National Science Library

    Jenekhe, S

    1999-01-01

    ... the self-assembly of new rod-coil diblock, rod- coil-rod triblock, and coil-rod-coil triblock copolymers from solution and the resulting discrete and periodic mesostmctares with sizes in the 100...

  19. Approssimazione all’edizione italiana della Cronica generale d’Hispagna et del regno di Valenza di Pere Antoni Beuter (Venezia, Gabriele Giolito de’ Ferrari, 1556: l’esemplare della “Biblioteca Civica” di Verona

    Directory of Open Access Journals (Sweden)

    Paola Bellomi

    2013-06-01

    Full Text Available Riassunto: Il presente saggio si propone come una prima approssimazione allo studio dell’edizioneitaliana della Cronaca generale d’Hispagna et del regno di Valenza di Pere Antoni Beuter, pubblicatanel 1556 a Venezia da Gabriele Giolito de’ Ferrari nella traduzione dello spagnolo Alfonso deUlloa. Quest’opera storiografica si inserisce in un contesto culturale importantissimo come quellodella Venezia del Cinquecento, particolarmente effervescente nel campo dell’editoria con figure diprim’ordine come Giolito e Ulloa. Il saggio si divide in tre momenti: il primo è costituito da unabreve introduzione sull’opera di Beuter e sulla traduzione di Ulloa; il secondo presenta la schedacatalografica dell’esemplare conservato presso la Biblioteca Civica di Verona; infine il terzo esponesinteticamente i contenuti della Cronaca.Parole chiave: Pere Antoni Beuter, Alfonso de Ulloa, Gabriele Giolito de’ Ferrari, Cronaca generaled’Hispagna et del regno di ValenzaAbstract: This essay is an approximation to the study of the the Italian edition of Pere AntoniBeuter’s Cronica generale d’Hispagna et del regno di Valenza, translated by the Spaniard Alfonso de Ulloa and published in Venice in 1556 by Gabriele Giolito de’ Ferrari. This chronicle is part of a majorcultural context, that of the Venice of the XVI century, very active in the emerging publishingbusiness with personalities such as Giolito and Ulloa. The essay is divided into three sections: 1. ashort introduction about the author and the translator; 2. the analytic description of the copy ofthe «Biblioteca Civica di Verona»; 3. the summaries of the contents of the Cronaca generale.Keywords: Pere Antoni Beuter, Alfonso de Ulloa, Gabriele Giolito de’ Ferrari, Cronaca generaled’Hispagna et del regno di Valenza, Biblioteca Civica di Verona

  20. Coil Migration through a Neuroform 3 Stent during Endovascular Coiling. A Case Report.

    LENUS (Irish Health Repository)

    O'Hare, A

    2009-07-29

    Summary: A 43-year-old woman attended for stent assisted coiling. A Neuroform 30 x 4.5 mm stent had been successfully placed over the left periophthalmic aneurysm. During the coiling the first coil migrated through the crowns in the stent, lodging at the MCA bifurcation. We believe that the coil herniated through the overlying stent due to the carotid siphon curvature and the open cell design. Furthermore the distal markers of the stent impeded coil extraction with a MERCI device.

  1. HTS planar gradiometer consisting of SQUID with multi-turn input coil and large pickup coil made of GdBCO coated conductor

    International Nuclear Information System (INIS)

    Tsukamoto, Akira; Adachi, Seiji; Oshikubo, Yasuo; Hato, Tsunehiro; Enpuku, Keiji; Sugisaki, Masaki; Arai, Eiichi; Tanabe, Keiichi

    2013-01-01

    Highlights: ► We fabricated a large HTS gradiometer with 350-mm-long baseline. ► A 6-turn gradiometric planar pickup was made of a HTS coated conductor. ► A 26-turn HTS input coil chip was stacked on a HTS thin film gradiometer chip. ► A mechanical balancing structure was also implemented. ► The fabricated gradiometer showed a gradient field noise of 0.8 fT/cm Hz 1/2 . -- Abstract: We have investigated the fabrication of a high-temperature superconducting (HTS) gradiometer with long baseline for geophysical applications. The proof-of-concept gradiometer using a 1-turn pickup coil made of a GdBa 2 Cu 3 O y coated conductor (GCC) and 5.5-turn input coil integrated on a SQUID was fabricated in our previous work. In this study, we have optimized the device structure to improve the frequency response, gradient field sensitivity and gradiometer balance. The fabricated flux transformer consists of a 6-turn planar gradiometric pickup coil and a 26-turn input coil made of an HTS thin film. A low-melting-point alloy was used to connect polished Ag surfaces of the CGG pickup coil and Au pads of the input coil. An HTS SQUID was formed on another substrate and stacked on the input coil. A mechanical balancing structure using three pieces of GCC as a superconducting shield was also implemented. The fabricated gradiometer showed a gradient field noise of 0.8 fT/cm Hz 1/2 in the white noise regions, a gradiometer balance of 1/142, and a cutoff frequency of 9 Hz corresponding to a 2 mΩ contact resistance between the pickup coil and the input coil

  2. ANL experimental program for pulsed superconducting coils

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1978-01-01

    Argonne National Laboratory (ANL) had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and started in aggressive development program in FY 1977. The main objectives for FY 1977 are to develop cryostable basic cable configurations with reasonably low ac losses, to develop 12 kA cryostable cable, using it to design and build a 1.5 MJ pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat for the 1.5 MJ pulsed coil. The principal objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil ranging from 2 T/s up to 12 T/s. Another objective in the pulsed coil program is to determine the feasibility of parallel coil operation in order to avoid excessive voltage and current requirements and to minimize the number of turns for the equilibrium field (EF) coils, should the EF coils be connected in parallel with the OH coils. A two-coil section model using the 11 kA cable will be built and tested

  3. Pulse coil concepts for the LCP Facility

    International Nuclear Information System (INIS)

    Nelson, B.E.; Burn, P.B.

    1977-01-01

    The pulse coils described in this paper are resistive copper magnets driven by time-varying currents. They are included in the Large Coil Test Facility (LCTF) portion of the Large Coil Program (LCP) to simulate the pulsed field environment of the toroidal coils in a tokamak reactor. Since TNS (a 150 sec, 5MA, igniting tokamak) and the Oak Ridge EPR (Experimental Power Reactor) are representative of the first tokamaks to require the technology developed in LCP, the reference designs for these machines, especially TNS, are used to derive the magnetic criteria for the pulse coils. This criteria includes the magnitude, distribution, and rate of change of pulsed fields in the toroidal coil windings. Three pulse coil concepts are evaluated on the basis of magnetic criteria and factors such as versatility of design, ease of fabrication and cost of operation. The three concepts include (1) a pair of poloidal coils outside the LCTF torus, (2) a single poloidal coil threaded through the torus, and (3) a pair of vertical axis coil windings inside the bore of one or more of the toroidal test coils

  4. ANL experimental program for pulsed superconducting coils

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1977-01-01

    Argonne National Laboratory (ANL) had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and started an aggressive development program in FY 1977. The main objectives for FY 1977 are to develop cryostable basic cable configurations with reasonably low ac losses, to develop 12 kA cryostable cable, using it to design and build a 1.5 MJ pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat for the 1.5 MJ pulsed coil. The principal objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil ranging from 2 T/s up to 12 T/s. Another objective in the pusled coil program is to determine the feasibility of parallel coil operation in order to avoid excessive voltage and current requirements and to minimize the number of turns for the equilibrium field (EF) coils, should the EF coils be connected in parallel with the OH coils. A two-coil section model using the 11 kA cable will be built and tested

  5. Performance evaluation of matrix gradient coils.

    Science.gov (United States)

    Jia, Feng; Schultz, Gerrit; Testud, Frederik; Welz, Anna Masako; Weber, Hans; Littin, Sebastian; Yu, Huijun; Hennig, Jürgen; Zaitsev, Maxim

    2016-02-01

    In this paper, we present a new performance measure of a matrix coil (also known as multi-coil) from the perspective of efficient, local, non-linear encoding without explicitly considering target encoding fields. An optimization problem based on a joint optimization for the non-linear encoding fields is formulated. Based on the derived objective function, a figure of merit of a matrix coil is defined, which is a generalization of a previously known resistive figure of merit for traditional gradient coils. A cylindrical matrix coil design with a high number of elements is used to illustrate the proposed performance measure. The results are analyzed to reveal novel features of matrix coil designs, which allowed us to optimize coil parameters, such as number of coil elements. A comparison to a scaled, existing multi-coil is also provided to demonstrate the use of the proposed performance parameter. The assessment of a matrix gradient coil profits from using a single performance parameter that takes the local encoding performance of the coil into account in relation to the dissipated power.

  6. Coiled transmission line pulse generators

    Science.gov (United States)

    McDonald, Kenneth Fox

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  7. E-coil: an inverse boundary element method for a quasi-static problem

    International Nuclear Information System (INIS)

    Sanchez, Clemente Cobos; Garcia, Salvador Gonzalez; Power, Henry

    2010-01-01

    Boundary element methods represent a valuable approach for designing gradient coils; these methods are based on meshing the current carrying surface into an array of boundary elements. The temporally varying magnetic fields produced by gradient coils induce electric currents in conducting tissues and so the exposure of human subjects to these magnetic fields has become a safety concern, especially with the increase in the strength of the field gradients used in magnetic resonance imaging. Here we present a boundary element method for the design of coils that minimize the electric field induced in prescribed conducting systems. This work also details some numerical examples of the application of this coil design method. The reduction of the electric field induced in a prescribed region inside the coils is also evaluated.

  8. E-coil: an inverse boundary element method for a quasi-static problem

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Clemente Cobos; Garcia, Salvador Gonzalez [Depto. Electromagnetismo y F. de la Materia Facultad de Ciencias University of Granada Avda. Fuentenueva E-18071 (Spain); Power, Henry, E-mail: ccobos@ugr.e [School of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham, Nottingham Park, Nottingham NG7 2RD (United Kingdom)

    2010-06-07

    Boundary element methods represent a valuable approach for designing gradient coils; these methods are based on meshing the current carrying surface into an array of boundary elements. The temporally varying magnetic fields produced by gradient coils induce electric currents in conducting tissues and so the exposure of human subjects to these magnetic fields has become a safety concern, especially with the increase in the strength of the field gradients used in magnetic resonance imaging. Here we present a boundary element method for the design of coils that minimize the electric field induced in prescribed conducting systems. This work also details some numerical examples of the application of this coil design method. The reduction of the electric field induced in a prescribed region inside the coils is also evaluated.

  9. Detailed 3D models of the induced electric field of transcranial magnetic stimulation coils

    Energy Technology Data Exchange (ETDEWEB)

    Salinas, F S; Lancaster, J L; Fox, P T [Research Imaging Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 (United States)

    2007-05-21

    Previous models neglected contributions from current elements spanning the full geometric extent of wires in transcranial magnetic stimulation (TMS) coils. A detailed account of TMS coil wiring geometry is shown to provide significant improvements in the accuracy of electric field (E-field) models. Modeling E-field dependence based on the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed E-field models were accurate up to the surface of the coil body (within 0.5% of measured) where simple models were often inadequate (up to 32% different from measured)

  10. Photoelastic and analytical investigation of stress in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.; Gray, W.H.

    1975-01-01

    A series of two-dimensional photoelastic stress analyses on circular and oval toroidal magnetic field coils for fusion reactors were made. The circumferential variation of the coil's magnetic force was simulated by applying different pressures to sixteen segmented regions of the inner surface of the models. Isochromatics and isoclinics were measured at selected points on the loaded model in a transmission polariscope using a microphotometer. Separate principal stresses were obtained using the combination of photoelastic information and isopachic data measured from the solution of Laplace's equation by the electrical analog method. Analysis of the same coil geometries, loadings, and boundary conditions were made using the finite element method. General agreement between theory and experiment was realized. From this investigation several variations of coil geometry and methods of support were evaluated. Based upon this experiment, suggestions for optimum structural design of toroidal field coils are presented

  11. Conformational switching in the coiled-coil domains of a proteasomal ATPase regulates substrate processing.

    Science.gov (United States)

    Snoberger, Aaron; Brettrager, Evan J; Smith, David M

    2018-06-18

    Protein degradation in all domains of life requires ATPases that unfold and inject proteins into compartmentalized proteolytic chambers. Proteasomal ATPases in eukaryotes and archaea contain poorly understood N-terminally conserved coiled-coil domains. In this study, we engineer disulfide crosslinks in the coiled-coils of the archaeal proteasomal ATPase (PAN) and report that its three identical coiled-coil domains can adopt three different conformations: (1) in-register and zipped, (2) in-register and partially unzipped, and (3) out-of-register. This conformational heterogeneity conflicts with PAN's symmetrical OB-coiled-coil crystal structure but resembles the conformational heterogeneity of the 26S proteasomal ATPases' coiled-coils. Furthermore, we find that one coiled-coil can be conformationally constrained even while unfolding substrates, and conformational changes in two of the coiled-coils regulate PAN switching between resting and active states. This switching functionally mimics similar states proposed for the 26S proteasome from cryo-EM. These findings thus build a mechanistic framework to understand regulation of proteasome activity.

  12. Dehumidification effects in the superheated region (SPR) of a direct expansion (DX) air cooling coil

    International Nuclear Information System (INIS)

    Xia Liang; Chan Mingyin; Deng Shiming; Xu Xiangguo

    2009-01-01

    A DX air cooling coil may normally be assumed to have two regions in its refrigerant side, according to refrigerant status, a two-phase region (TPR) and a superheated region (SPR). Dry air side surface of the SPR in a DX air cooling coil has been normally assumed in lumped-parameter mathematical models previously developed without however being validated. Therefore, an experimental study has been carried out to examine such an assumption under different operating conditions. The experimental results suggested that the air side surface of the SPR in a DX air cooling coil was either fully or partially wet under all experimental conditions and assuming dry air side of the SPR could lead to an underestimated total amount of water vapor condensed on the entire DX coil surface. Therefore, it is recommended that the assumption of dry air side in a SPR be no longer used in future lumped-parameter models to be developed for improved modeling accuracy.

  13. Remote maintenance of tandem mirror hybrid coils

    International Nuclear Information System (INIS)

    Dietz, L.P.

    1983-01-01

    Hybrid Coils (superconducting coils with normal conducting inserts) are being employed with increasing frequency on Tandem Mirror Devices to obtain high field strengths. The normal conducting copper inserts are short lived in comparison to their encircling superconductors. It becomes desirable, therefore, to devise design features and maintenance procedures to replace the inner normal conducting coils without simultaneously replacing the longer lived (and significantly more costly) superconducting coils. The high neutron wall loadings require that the task be accomplished by remote control. The approach is to permanently mount the coil assemblies on track mounted carriages which serve, during machine operation merely as structural supports, but during maintenance procedures as moveable transport devices. The carriages incorporate all necessary provisions to facilitate remote maintenance operations and to adjust and align the coil assemblies with respect to adjacent machine components. The vacuum vessel is severed on both sides of the hybrid coil by means of a remote cutting machine. The entire coil is transported horizontally, normal to the machine axis to a nearby repair station. Prepositioned carriage mounted repair equipment at the repair station withdraws the damaged normal coil as a single entity and inserts a preassembled spare unit. The repaired hybrid coil is reassembled to the reactor. A cost and risk effective procedure has been evolved to maintain one of the more critical components of a Tandem Mirror Machine

  14. Discussion of discrete D shape toroidal coil

    International Nuclear Information System (INIS)

    Kaiho, Katsuyuki; Ohara, Takeshi; Agatsuma, Ko; Onishi, Toshitada

    1988-01-01

    A novel design for a toroidal coil, called the D shape coil, was reported by J. File. The coil conductors are in pure tension and then subject to no bending moment. This leads to a smaller number of emf supports in a simpler configuration than that with the conventional toroidal coil of circular cross-section. The contours of the D shape are given as solutions of a differential equation. This equation includes the function of the magnetic field distribution in the conductor region which is inversely proportional to the winding radius. It is therefore important to use the exact magnetic field distribution. However the magnetic field distribution becomes complicated when the D shape toroidal coil is comprised of discrete coils and also depends on the D shape configuration. A theory and a computer program for designing the practical pure-tension toroidal coil are developed. Using this computer code, D shape conductors are calculated for various numbers of discrete coils and the results are compared. Electromagnetic forces in the coils are also calculated. It is shown that the hoop stress in the conductors depends only on the total ampere-turns of the coil when the contours of the D shape are similar. (author)

  15. Large coil test facility conceptual design report

    International Nuclear Information System (INIS)

    Nelms, L.W.; Thompson, P.B.; Mann, T.L.

    1978-02-01

    In the development of a superconducting toroidal field (TF) magnet for The Next Step (TNS) tokamak reactor, several different TF coils, about half TNS size, will be built and tested to permit selection of a design and fabrication procedure for full-scale TNS coils. A conceptual design has been completed for a facility to test D-shaped TF coils, 2.5 x 3.5-m bore, operating at 4-6 K, cooled either by boiling helium or by forced-flow supercritical helium. Up to six coils can be accommodated in a toroidal array housed in a single vacuum tank. The principal components and systems in the facility are an 11-m vacuum tank, a test stand providing structural support and service connections for the coils, a liquid nitrogen system, a system providing helium both as saturated liquid and at supercritical pressure, coils to produce a pulsed vertical field at any selected test coil position, coil power supplies, process instrumentation and control, coil diagnostics, and a data acquisition and handling system. The test stand structure is composed of a central bucking post, a base structure, and two horizontal torque rings. The coils are bolted to the bucking post, which transmits all gravity loads to the base structure. The torque ring structure, consisting of beams between adjacent coils, acts with the bucking structure to react all the magnetic loads that occur when the coils are energized. Liquid helium is used to cool the test stand structure to 5 K to minimize heat conduction to the coils. Liquid nitrogen is used to precool gaseous helium during system cooldown and to provide thermal radiation shielding

  16. Empirical Correlation of the Morphology of Coiled Carbon Nano tubes with Their Response to Axial Compression

    International Nuclear Information System (INIS)

    Barber, J.R.; Boyles, J.S.; Bottomley, L.A.; Ferri, A.A.

    2014-01-01

    The mechanical response of thirteen different helical multi-walled carbon nano coils to axial compression is reported. Each nano coil was attached to the apex of a cantilever probe tip; its dimensions and orientation relative to the tip apex were determined with scanning electron microscopy. The atomic force microscope was employed to apply a cyclic axial load on the nano coil. Its mechanical response was determined by simultaneous collection of the thermal resonance frequency, displacement, and oscillation amplitude of the cantilever-nano tube system in real time. Depending upon compression parameters, each coil underwent buckling, bending, and slip-stick motion. Characteristic features in the thermal resonance spectrum and in the force and oscillation amplitude curves for each of these responses to induced stress are presented. Following compression studies, the structure and morphology of each nano coil were determined by transmission electron microscopy. The compression stiffness of each nano coil was estimated from the resonant frequency of the cantilever at the point of contact with the substrate surface. From this value, the elastic modulus of the nano coil was computed and correlated with the coiled carbon nano tube’s morphology.

  17. Development of a new error field correction coil (C-coil) for DIII-D

    International Nuclear Information System (INIS)

    Robinson, J.I.; Scoville, J.T.

    1995-12-01

    The C-coil recently installed on the DIII-D tokamak was developed to reduce the error fields created by imperfections in the location and geometry of the existing coils used to confine, heat, and shape the plasma. First results from C-coil experiments include stable operation in a 1.6 MA plasma with a density less than 1.0 x 10 13 cm -3 , nearly a factor of three lower density than that achievable without the C-coil. The C-coil has also been used in magnetic braking of the plasma rotation and high energy particle confinement experiments. The C-coil system consists of six individual saddle coils, each 60 degree wide toroidally, spanning the midplane of the vessel with a vertical height of 1.6 m. The coils are located at a major radius of 3.2 m, just outside of the toroidal field coils. The actual shape and geometry of each coil section varied somewhat from the nominal dimensions due to the large number of obstructions to the desired coil path around the already crowded tokamak. Each coil section consists of four turns of 750 MCM insulated copper cable banded with stainless steel straps within the web of a 3 in. x 3 in. stainless steel angle frame. The C-coil structure was designed to resist peak transient radial forces (up to 1,800 Nm) exerted on the coil by the toroidal and ploidal fields. The coil frames were supported from existing poloidal field coil case brackets, coil studs, and various other structures on the tokamak

  18. Argonne National Laboratory superconducting pulsed coil program

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.

    1979-01-01

    The main objectives are to develop high current (approx. 100 kA) cryostable cable configurations with reasonably low ac losses, to build a demonstration pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat. A 1.5-MJ cryostable pulsed superconducting coil has been developed and constructed at ANL. The coil has a peak field of 4.5 T at an operating current of 11.0 kA. A large inexpensive plastic cryostat has been developed for testing the pulsed coil. The coil has been pulsed with a maximum dB/dt of 11 T/s. The coil was pulsed more than 4000 cycles. Detailed results of the ac loss measurements and the current sharing of the cryostability will be described

  19. Test facility for PLT TF coils

    International Nuclear Information System (INIS)

    Hearney, J.; File, J.; Dreskin, S.

    1975-01-01

    Past experience with the model C stellerator and other toroidal field devices indicates that mechanical and electrical tests of a toroidal field coil prior to maximum field operation of the device is prudent and desirable. This paper describes a test program for the PLT-TF coils. The test stand consists of one test coil, two background coils and a steel supporting structure. The three coil configuration produces a 67.5 kG field at the inner conductor (38 kG at the bore center) and simulates a 1/R field distribution in the bore of the test coil. The resolution of the field force system and resultant stresses within the test structure are discussed. A test procedure is described which maximizes the information obtained from a 100,000 pulse program

  20. Power loss problems in EXTRAP coil systems

    International Nuclear Information System (INIS)

    Lehnert, B.

    1977-02-01

    The Ohmic power loss in the coils of external ring traps is minimized with respect to the thermonuclear power production. In the case of the DT-reaction this leads to dimensions and power densities being relevant to full-scale reactors. Not only superconducting or refrigerated coil windings can thus be used, but also hot-coil systems which are operated at several hundred degrees centrigrade and form part of a steam cycle and power extraction system. For hot coils the problems of void formation and tritium regeneration have to be further examined. The high beta value leads to moderately large coil stresses. Finally, replacement and repair become simplified by the present coil geometry. (Auth.)

  1. Coil supporting device for thermonuclear device

    International Nuclear Information System (INIS)

    Okubo, Minoru; Ando, Toshiro; Ota, Mitsuru; Ishimura, Masabumi.

    1979-01-01

    Purpose: To lower the bending stress exerted on coils thereby preventing the coils from deformation by branching the outer circumferential support frames of coil support frames disposed at an equal pitch circumferentially to the coils into plurality, and integrally forming them to the inner circumferential support frames. Constitution: Each of the support frames for supporting poloidal coils winding around a vacuum vessel is bisected at the radial midway so that the outer circumferential branches are disposed at an equal pitch and they are formed integrally with the inner circumferential support frames. The inner circumferential support frames are fixed by support posts on a bed and the outer circumferential support frames are mounted to the outer edge of wedge-like support posts. Accordingly, if the coils expand outwardly upon increase in the temperature, the stress exerted on the support frame can be decreased. (Yoshino, Y.)

  2. Split-coil-system SULTAN

    International Nuclear Information System (INIS)

    Vecsey, G.

    1992-08-01

    The high field superconductor test facility SULTAN started operation successfully in May 1992. Originally designed for testing full scale conductors for the large magnets of the next generation fusion reactors, the SULTAN facility installed at PSI (Switzerland) was designed as a common venture of three European Laboratories: ENEA (Italy), ECN (Netherlands) and PSI, and built by ENEA and PSI in the framework of the Euratom Fusion Technology Program. Presently the largest facility in the world, with its superconducting split coil system generating 11 Tesla in a 0.6 m bore, it is ready now for testing superconductor samples with currents up to 50 kA at variable cooling conditions. Similar tests can be arranged also for other applications. SULTAN is offered by the European Community as a contribution to the worldwide cooperation for the next step of fusion reactor development ITER. First measurements on conductor developed by CEA (Cadarache) are now in progress. Others like those of ENEA and CERN will follow. For 1993, a test of an Italian 12 TZ model coil for fusion application is planned. SULTAN is a worldwide unique facility marking the competitive presence of Swiss technology in the field of applied superconductivity research. Based on development and design of PSI, the high field Nb 3 Sn superconductors and coils were fabricated at the works of Kabelwerke Brugg and ABB, numerous Swiss companies contributed to the success of this international effort. Financing of the Swiss contribution of SULTAN was made available by NEFF, BEW, BBW, PSI and EURATOM. (author) figs., tabs., 20 refs

  3. Photoelastic analyses of stresses in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.

    1977-02-01

    Several two-dimensional photoelastic stress analyses were made on models of circular and oval toroidal magnetic field coils for fusion reactors. The circumferential variation of each coil's in-plane magnetic force was simulated by applying different pressures to 16 segmented regions of the inner surface of the models. One special loading fixture was used for the model of each shape and size. Birefringence and isoclinic angles were measured in a transmission polariscope at selected points on the loaded model. Boundary stresses in the cases of known boundary conditions were determined directly from the isochromatics. Separate principal stresses were calculated using the combination of photoelastic information and isopachic data obtained by the electrical analogy method from the solution of Laplace's equation. Comparisons were made between experimental results and those computed using the finite element method. The stress distribution between theoretical and experimental agrees very well, although the finite element method yielded slightly higher stresses than the photoelastic method; further work is needed to resolve this difference. In this investigation several variations of coil geometry and methods of support were evaluated. Based on experimental results, optimum structural designs of toroidal field coils were recommended

  4. Offset coil designs for superconducting magnets, a logical development

    International Nuclear Information System (INIS)

    Collins, T.

    1986-03-01

    Dipoles and quadrupoles for any new, large proton ring must be stronger, smaller and have better field shape (systematic error) than those used in the Doubler. The present two-shell designs are rigid in that the coils are too thin but cannot be relatively fatter without destroying the field quality. An examination of the coil shapes for dipoles and quadrupoles which produce perfect fields from a uniform current density shows clearly that our persistent use of a circular form for the inner surface of the coils is a poor approximation. When this is corrected by ''offsets'' there is a striking improvement both in the strength of fields and in the field quality. The same analysis makes clear that the efficient use of superconductor and the overall magnet size is determined by the perfect coil shapes. Any reasonable magnet will not differ significantly from the ideal for these parameters. This will be particularly helpful in setting design goals for very large quadrupoles. The offset two-shell dipole design preserves the mechanical features of the highly successful, resilient doubler magnets while greatly extending the performance

  5. This immortal coil? New CT rigs duel against singles

    Energy Technology Data Exchange (ETDEWEB)

    Creighton, J.

    1998-12-01

    New competition to conventional single rigs that have changed little in the last four decades face new competition from next-generation coiled tubing (CT) units which have multi-function capabilities, ranging from driving onto leases, drilling and setting surface case to cementing. Several of these new units are ready to challenge the conventional single rigs. Their ability to perform at high penetration rates (up to twice what single rigs can do) is expected to significantly cut drill time, with corresponding cost savings for both contractors and operators. Serval Corporation and Fleet Coiled Services are just two of the drilling service companies that have launched new shallow grass roots coiled tubing drilling units recently, gambling that the new technology will win over conventional methods hands down. Some major companies, like Fracmaster Ltd. and NOWSCO Well Service Ltd., have targeted the re-entry and horizontal markets, a much more difficult technical challenge, sinking billions of dollars of research and development money into advancing the most technically difficult applications of coil technology.

  6. Biocide-mediated corrosion of coiled tubing.

    Science.gov (United States)

    Sharma, Mohita; An, Dongshan; Liu, Tao; Pinnock, Tijan; Cheng, Frank; Voordouw, Gerrit

    2017-01-01

    Coiled tubing corrosion was investigated for 16 field water samples (S5 to S20) from a Canadian shale gas field. Weight loss corrosion rates of carbon steel beads incubated with these field water samples averaged 0.2 mm/yr, but injection water sample S19 had 1.25±0.07 mm/yr. S19 had a most probable number of zero acid-producing bacteria and incubation of S19 with carbon steel beads or coupons did not lead to big changes in microbial community composition. In contrast other field water samples had most probable numbers of APB of 102/mL to 107/mL and incubation of these field water samples with carbon steel beads or coupons often gave large changes in microbial community composition. HPLC analysis indicated that all field water samples had elevated concentrations of bromide (average 1.6 mM), which may be derived from bronopol, which was used as a biocide. S19 had the highest bromide concentration (4.2 mM) and was the only water sample with a high concentration of active bronopol (13.8 mM, 2760 ppm). Corrosion rates increased linearly with bronopol concentration, as determined by weight loss of carbon steel beads, for experiments with S19, with filtered S19 and with bronopol dissolved in defined medium. This indicated that the high corrosion rate found for S19 was due to its high bronopol concentration. The corrosion rate of coiled tubing coupons also increased linearly with bronopol concentration as determined by electrochemical methods. Profilometry measurements also showed formation of multiple pits on the surface of coiled tubing coupon with an average pit depth of 60 μm after 1 week of incubation with 1 mM bronopol. At the recommended dosage of 100 ppm the corrosiveness of bronopol towards carbon steel beads was modest (0.011 mm/yr). Higher concentrations, resulting if biocide is added repeatedly as commonly done in shale gas operations, are more corrosive and should be avoided. Overdosing may be avoided by assaying the presence of residual biocide by HPLC

  7. DEVELOPMENT OF COILED TUBING STRESS ANALYSIS

    Directory of Open Access Journals (Sweden)

    Davorin Matanović

    1998-12-01

    Full Text Available The use of coiled tubing is increasing rapidly with drilling of horizontal wells. To satisfy all requirements (larger mechanical stresses, larger fluid capacities the production of larger sizes and better material qualities was developed. Stresses due to axial forces and pressures that coiled tubing is subjected are close to its performance limits. So it is really important to know and understand the behaviour of coiled tubing to avoid its break, burst or collapse in the well.

  8. Assessment of the characteristics of MRI coils in terms of RF non-homogeneity using routine spin echo sequences

    International Nuclear Information System (INIS)

    Oghabian, M. A.; Mehdipour, Sh.; RiahicAlam, N.; Rafie, B.; Ghanaati, H.

    2005-01-01

    One of the major causes of image non-uniformity in MRI is due to the existence of non-homogeneity in RF receive and transmit. This can be the most effective source of error in quantitative studies in MRI imaging. Part of this non-homogeneity demonstrates the characteristics of RF coil and part of it is due to the interaction of RF field with the material being imaged. In this study, RF field non-homogeneity of surface and volume coils is measured using an oil phantom. The method employed in this work is based on a routine Spin Echo based sequence as proposed by this group previously. Materials and Methods: For the determination of RF non-uniformity, a method based on Spin Echo sequence (8θ-180) was used as reported previously by the same author. In this method, several images were obtained from one slice using different flip angles while keeping all other imaging parameters constant. Then, signal intensity at a ROI from all of these images were measured and fitted to the MRI defined mathematical model. Since this mathematical model describes the relation between signal intensity and flip angle in a (8θ-180) Spin Echo sequence, it is possible to obtain the variation in receive and transmit sensitivity in terms of the variation of signal intensity from the actual expected values. Since surface coils are functioning as only receiver (RF transmission is done by Body coil), first the results of receive coil homogeneity is measured, then characteristic of transmit coil (for the body coil) is evaluated Results: The coefficient of variation (C.V.) found for T(r) value obtained from images using head coils was in the order of 0.6%. Since the head coil is functioning as both transmitter and receiver, any non-uniformity in either transmit or receive stage can lead to non-homogeneity in RF field. A part from the surface coils, the amount of non-homogeneity due to receive coil was less than that of the transmit coil. In the case of the surface coils the variation in receive

  9. Manufacturing development of the Westinghouse Nb3Sn coil for the Large Coil Test Program

    International Nuclear Information System (INIS)

    Young, J.L.; Vota, T.L.; Singh, S.K.

    1983-01-01

    The Westinghouse Nb 3 Sn Magnet for the Oak Ridge National Laboratory Large Coil Program (LCP) is currently well into the manufacturing phase. This paper identifies the manufacturing processes and development tasks for his unique, advanced coil

  10. Optimization of the ECT background coil

    International Nuclear Information System (INIS)

    Ballou, J.K.; Luton, J.N.

    1975-01-01

    This study was begun to optimize the Eccentric Coil Test (ECT) background coil. In the course of this work a general optimization code was obtained, tested, and applied to the ECT problem. So far this code has proven to be very satisfactory. The results obtained with this code and earlier codes have illustrated the parametric behavior of such a coil system and that the optimum for this type system is broad. This study also shows that a background coil with a winding current density of less than 3000 A/cm 2 is not feasible for the ECT models presented in this paper

  11. Magnetic field coil in nuclear fusion device

    International Nuclear Information System (INIS)

    Yamaguchi, Mitsugi; Takano, Hirohisa.

    1975-01-01

    Object: To provide an electrical-insulatively stabilized magnetic field coil in nuclear fusion device, restraining an increase in voltage when plasma current is rapidly changed. Structure: A magnetic field coil comprises coils arranged coaxial with respective vacuum vessels, said coils being wound in positive and reverse polarities so as to form a vertical magnetic field within the plasma. The coils of the positive polarity are arranged along the vacuum vessel inside of an axis vertical in section of the annular plasma and are arranged symmetrically up and down of a horizontal axis. On the other hand, the coils of the reverse polarity are arranged along the vacuum vessel outside of a vertical axis and arranged symmetrically up and down of the horizontal axis. These positive and reverse polarity coils are alternately connected in series, and lead portions of the coils are connected to a power source by means of connecting wires. In this case, lead positions of the coils are arranged in one direction, and the connecting wires are disposed in closely contact relation to offset magnetic fields formed by the connecting wires each other. (Kawakami, Y.)

  12. A precise technique for manufacturing correction coil

    International Nuclear Information System (INIS)

    Schieber, L.

    1992-01-01

    An automated method of manufacturing correction coils has been developed which provides a precise embodiment of the coil design. Numerically controlled machines have been developed to accurately position coil windings on the beam tube. Two types of machines have been built. One machine bonds the wire to a substrate which is wrapped around the beam tube after it is completed while the second machine bonds the wire directly to the beam tube. Both machines use the Multiwire reg-sign technique of bonding the wire to the substrate utilizing an ultrasonic stylus. These machines are being used to manufacture coils for both the SSC and RHIC

  13. Tesla coil theoretical model and experimental verification

    OpenAIRE

    Voitkans, Janis; Voitkans, Arnis

    2014-01-01

    Abstract – In this paper a theoretical model of a Tesla coil operation is proposed. Tesla coil is described as a long line with distributed parameters in a single-wired format, where the line voltage is measured against electrically neutral space. It is shown that equivalent two-wired scheme can be found for a single-wired scheme and already known long line theory can be applied to a Tesla coil. Formulas for calculation of voltage in a Tesla coil by coordinate and calculation of resonance fre...

  14. A novel target-field method for finite-length magnetic resonance shim coils: I. Zonal shims

    International Nuclear Information System (INIS)

    Forbes, Lawrence K.; Crozier, Stuart

    2001-01-01

    This paper presents a new approach for the design of genuinely finite-length shim and gradient coils, intended for use in magnetic resonance imaging equipment. A cylindrical target region is located asymmetrically, at an arbitrary position within a coil of finite length. A desired target field is specified on the surface of that region, and a method is given that enables winding patterns on the surface of the coil to be designed, to produce the desired field at the inner target region. The method uses a minimization technique combined with regularization, to find the current density on the surface of the coil. The method is illustrated for linear, quadratic and cubic magnetic target fields located asymmetrically within a finite-length coil. (author)

  15. Superconducting Coil of Po Dipole

    CERN Multimedia

    1983-01-01

    The Po superconducting dipole was built as a prototype beam transport magnet for the SPS extracted proton beam P0. Its main features were: coil aperture 72 mm, length 5 m, room-temperature yoke, NbTi cable conductor impregnated with solder, nominal field 4.2 T at 4.7 K (87% of critical field). It reached its nominal field without any quench.After this successful test up to its nominal field of 4.2 T, the power was not raised to reach a quench. The magnet was not installed in a beam and had no other further use. Nevertheless its construction provided knowledges and experience which became useful in the design and construction of the LHC magnets. The photo shows a detail of the inner layer winding before superposing the outer layer to form the complete coil of a pole. Worth noticing is the interleaved glass-epoxy sheet (white) with grooved channels for the flow of cooling helium. See also 8211532X.

  16. Self-assembly of coiled coil peptides into nanoparticles vs 2-d plates: effects of assembly pathway

    Science.gov (United States)

    Kim, Kyunghee; Pochan, Darrin

    Molecular solution assembly, or self-assembly, is a process by which ordered nanostructures or patterns are formed by non-covalent interactions during assembly. Biomimicry, the use of bioinspired molecules or biologically relevant materials, is an important area of self-assembly research with peptides serving a critical role as molecular tools. The morphology of peptide assemblies can be controlled by adjusting solution conditions such as the concentration of peptides, the temperature, and pH. Herein, spherical nanostructures, which have potential for creating an encapsulation system, are formed by self-assembly when coiled coil peptides are combined in solution. These peptides are homotrimeric and heterodimeric coiled-coil bundles and the homotrimer is connected with each of heterodimer through their external surfaces via disulfide bonds. The resultant covalent constructs could co-assemble into complementary trimeric hubs, respectively. The two peptide constructs are directly mixed and assembled in solution in order to produce either spherical particles or 2-d plates depending on the solution conditions and kinetic pathway of assembly. In particular, structural changes of the self-assembled peptides are explored by control of the thermal history of the assembly solution.

  17. Three-dimensional proton magnetic resonance spectroscopic imaging with and without an endorectal coil: a prostate phantom study

    NARCIS (Netherlands)

    Ma, C.; Chen, L.; Scheenen, T.W.J.; Lu, J.; Wang, J

    2015-01-01

    Proton magnetic resonance spectroscopic imaging (MRSI) of the prostate has been used with only a combination of external surface coils. The quality of spectral fitting of the (choline + creatine)/citrate ([Cho + Cr]/Cit) ratio at different field strengths and different coils is important for

  18. Micro-fabricated integrated coil and magnetic circuit and method of manufacturing thereof

    Science.gov (United States)

    Mihailovich, Robert E.; Papavasiliou, Alex P.; Mehrotra, Vivek; Stupar, Philip A.; Borwick, III, Robert L.; Ganguli, Rahul; DeNatale, Jeffrey F.

    2017-03-28

    A micro-fabricated electromagnetic device is provided for on-circuit integration. The electromagnetic device includes a core. The core has a plurality of electrically insulating layers positioned alternatingly between a plurality of magnetic layers to collectively form a continuous laminate having alternating magnetic and electrically insulating layers. The electromagnetic device includes a coil embedded in openings of the semiconductor substrate. An insulating material is positioned in the cavity and between the coil and an inner surface of the core. A method of manufacturing the electromagnetic device includes providing a semiconductor substrate having openings formed therein. Windings of a coil are electroplated and embedded in the openings. The insulating material is coated on or around an exposed surface of the coil. Alternating magnetic layers and electrically insulating layers may be micro-fabricated and electroplated as a single and substantially continuous segment on or around the insulating material.

  19. Multicoil2: predicting coiled coils and their oligomerization states from sequence in the twilight zone.

    Directory of Open Access Journals (Sweden)

    Jason Trigg

    Full Text Available The alpha-helical coiled coil can adopt a variety of topologies, among the most common of which are parallel and antiparallel dimers and trimers. We present Multicoil2, an algorithm that predicts both the location and oligomerization state (two versus three helices of coiled coils in protein sequences. Multicoil2 combines the pairwise correlations of the previous Multicoil method with the flexibility of Hidden Markov Models (HMMs in a Markov Random Field (MRF. The resulting algorithm integrates sequence features, including pairwise interactions, through multinomial logistic regression to devise an optimized scoring function for distinguishing dimer, trimer and non-coiled-coil oligomerization states; this scoring function is used to produce Markov Random Field potentials that incorporate pairwise correlations localized in sequence. Multicoil2 significantly improves both coiled-coil detection and dimer versus trimer state prediction over the original Multicoil algorithm retrained on a newly-constructed database of coiled-coil sequences. The new database, comprised of 2,105 sequences containing 124,088 residues, includes reliable structural annotations based on experimental data in the literature. Notably, the enhanced performance of Multicoil2 is evident when tested in stringent leave-family-out cross-validation on the new database, reflecting expected performance on challenging new prediction targets that have minimal sequence similarity to known coiled-coil families. The Multicoil2 program and training database are available for download from http://multicoil2.csail.mit.edu.

  20. Design of the coolant system for the Large Coil Test Facility pulse coils

    International Nuclear Information System (INIS)

    Bridgman, C.; Ryan, T.L.

    1983-01-01

    The pulse coils will be a part of the Large Coil Test Facility in Oak Ridge, Tennessee, which is designed to test six large tokamak-type superconducting coils. The pulse coil set consists of two resistive coaxial solenoid coils, mounted so that their magnetic axis is perpendicular to the toroidal field lines of the test coil. The pulse coils provide transient vertical fields at test coil locations to simulate the pulsed vertical fields present in tokamak devices. The pulse coils are designed to be pulsed for 30 s every 150 s, which results in a Joule heating of 116 kW per coil. In order to provide this capability, the pulse coil coolant system is required to deliver 6.3 L/s (100 gpm) of subcooled liquid nitrogen at 10-atm absolute pressure. The coolant system can also cool down each pulse coil from room temperature to liquid nitrogen temperature. This paper provides details of the pumping and heat exchange equipment designed for the coolant system and of the associated instrumentation and controls

  1. Salt effects on hydrophobic interaction and charge screening in the folding of a negatively charged peptide to a coiled coil (leucine zipper).

    Science.gov (United States)

    Jelesarov, I; Dürr, E; Thomas, R M; Bosshard, H R

    1998-05-19

    The stability of a coiled coil or leucine zipper is controlled by hydrophobic interactions and electrostatic forces between the constituent helices. We have designed a 30-residue peptide with the repeating seven-residue pattern of a coiled coil, (abcdefg)n, and with Glu in positions e and g of each heptad. The glutamate side chains prevented folding at pH values above 6 because of electrostatic repulsion across the helix dimer interface as well as within the individual helices. Protonation of the carboxylates changed the conformation from a random coil monomer to a coiled coil dimer. Folding at alkaline pH where the peptide had a net charge of -7e was promoted by the addition of salts. The nature of the charge screening cation was less important than that of the anion. The high salt concentrations (>1 M) necessary to induce folding indicated that the salt-induced folding resulted from alterations in the protein-water interaction. Folding was promoted by the kosmotropic anions sulfate and fluoride and to a lesser extent by the weak kosmotrope formate, whereas chloride and the strong chaotrope perchlorate were ineffective. Kosmotropes are excluded from the protein surface, which is preferentially hydrated, and this promotes folding by strengthening hydrophobic interactions at the coiled coil interface. Although charge neutralization also contributed to folding, it was effective only when the screening cation was partnered by a good kosmotropic anion. Folding conformed to a two-state transition from random coil monomer to coiled coil dimer and was enthalpy driven and characterized by a change in the heat capacity of unfolding of 3.9 +/- 1.2 kJ mol-1 K-1. The rate of folding was analyzed by fluorescence stopped-flow measurements. Folding occurred in a biphasic reaction in which the rapid formation of an initial dimer (kf = 2 x 10(7) M-1 s-1) was followed by an equally rapid concentration-independent rearrangement to the folded dimer (k > 100 s-1).

  2. Measurement of heating coil temperature for e-cigarettes with a "top-coil" clearomizer.

    Science.gov (United States)

    Chen, Wenhao; Wang, Ping; Ito, Kazuhide; Fowles, Jeff; Shusterman, Dennis; Jaques, Peter A; Kumagai, Kazukiyo

    2018-01-01

    To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a "top-coil" clearomizer, and to make associations of coil conditions with emission of toxic carbonyl compounds by combining results herein with the literature. The coil temperature of a second generation e-cigarette was measured at various applied power levels, coil conditions, and e-liquid compositions, including (1) measurements by thermocouple at three e-liquid fill levels (dry, wet-through-wick, and full-wet), three coil resistances (low, standard, and high), and four voltage settings (3-6 V) for multiple coils using propylene glycol (PG) as a test liquid; (2) measurements by thermocouple at additional degrees of coil wetness for a high resistance coil using PG; and (3) measurements by both thermocouple and infrared (IR) camera for high resistance coils using PG alone and a 1:1 (wt/wt) mixture of PG and glycerol (PG/GL). For single point thermocouple measurements with PG, coil temperatures ranged from 322 ‒ 1008°C, 145 ‒ 334°C, and 110 ‒ 185°C under dry, wet-through-wick, and full-wet conditions, respectively, for the total of 13 replaceable coil heads. For conditions measured with both a thermocouple and an IR camera, all thermocouple measurements were between the minimum and maximum across-coil IR camera measurements and equal to 74% ‒ 115% of the across-coil mean, depending on test conditions. The IR camera showed details of the non-uniform temperature distribution across heating coils. The large temperature variations under wet-through-wick conditions may explain the large variations in formaldehyde formation rate reported in the literature for such "top-coil" clearomizers. This study established a simple and straight-forward protocol to systematically measure e-cigarette coil heating temperature under dry, wet-through-wick, and full-wet conditions. In addition to applied power, the

  3. Progress on large superconducting toroidal field coils

    International Nuclear Information System (INIS)

    Haubenreich, P.N.; Luton, J.N.; Thompson, P.B.; Beard, D.S.

    1979-01-01

    Large superconducting toroidal field coils of competing designs are being produced by six major industrial teams. In the US, teams headed by General Dynamics Convair, General Electric, and Westinghouse are under contract to design and fabricate one coil each to specifications established by the Large Coil Program. A facility for testing 6 coils in a toroidal array at fields to 8 to 12 tesla is under construction at Oak Ridge. Through an international agreement, EURATOM, Japan, and Switzerland will produce one coil each for testing with the US coils. Each test coil will have a 2.5 x 3.5 m D-shape winding bore and is designed to operate at a current of 10 to 18 kA at a peak field of 8T while subjected to pulsed fields of 0.14 T applied in 1.0 s. There are significant differences among the six coil designs: five use NbTi, one Nb 3 Sn; three are cooled by pool boiling helium, three by forced flow; five have welded or bolted stainless steel coil cases, one has aluminum plate structure. All are designed to be cryostable at 8T, with structural margin for extended operation. The three US coil teams are almost or completely finished with detailed design and are now procuring materials and setting up manufacturing equipment. The non-US teams are at various stages of verification testing and design. The GDC and GE coils are scheduled for delivery in the spring of 1981 and the others will be completed a year later. The 11-m diameter vessel at the test facility has been completed and major components of the test stand are being procured. Engineering and procurement to upgrade the helium liquifier-refrigerator system are under way

  4. RF Magnetic Field Uniformity of Rectangular Planar Coils for Resonance Imaging

    Science.gov (United States)

    2016-02-04

    magnetic, potassium chlorate , nuclear quadrupole resonance, uniform field, coil, surface coil I. INTRODUCTION QR is a magnetic resonance phenomenon...material that will be used is this investigation is potassium chlorate (KCLO3). This paper utilizes the NQR signals detection from KCLO3 to determine the...frequency of potassium chlorate (KCLO3), and matched to a 50 ohm input impedance using L-network circuit of capacitors. Fig.1 shows a diagram of the

  5. Outcomes with single-coil versus dual-coil implantable cardioverter defibrillators: a meta-analysis.

    Science.gov (United States)

    Sunderland, Nicholas; Kaura, Amit; Murgatroyd, Francis; Dhillon, Para; Scott, Paul A

    2018-03-01

    Dual-coil implantable cardioverter defibrillator (ICD) leads have traditionally been used over single-coil leads due to concerns regarding high defibrillation thresholds (DFT) and consequent poor shock efficacy. However, accumulating evidence suggests that this position may be unfounded and that dual-coil leads may also be associated with higher complication rates during lead extraction. This meta-analysis collates data comparing dual- and single-coil ICD leads. Electronic databases were systematically searched for randomized controlled trials (RCT) and non-randomized studies comparing single-coil and dual-coil leads. The mean differences in DFT and summary estimates of the odds-ratio (OR) for first-shock efficacy and the hazard-ratio (HR) for all-cause mortality were calculated using random effects models. Eighteen studies including a total of 138,124 patients were identified. Dual-coil leads were associated with a lower DFT compared to single coil leads (mean difference -0.83J; 95% confidence interval [CI] -1.39--0.27; P = 0.004). There was no difference in the first-shock success rate with dual-coil compared to single-coil leads (OR 0.74; 95%CI 0.45-1.21; P=0.22). There was a significantly lower risk of all-cause mortality associated with single-coil leads (HR 0.91; 95%CI 0.86-0.95; P dual-coil leads. The mortality benefit with single-coil leads most likely represents patient selection bias. Given the increased risk and complexity of extracting dual-coil leads, centres should strongly consider single-coil ICD leads as the lead of choice for routine new left-sided ICD implants. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  6. HydroCoil as an adjuvant to bare platinum coil treatment of 100 cerebral aneurysms

    International Nuclear Information System (INIS)

    Fanning, Noel F.; Berentei, Zsolt; Brennan, Paul R.; Thornton, John

    2007-01-01

    Introduction The overall safety of the HydroCoil, an expansile hybrid hydrogel-platinum coil, is unknown. We report a prospective observational study of our first 100 cerebral aneurysms treated with HydroCoils, focusing on safety and initial efficacy.Methods Indications, procedural complications, clinical and angiographic outcomes were recorded. Packing density, number of coils deployed and angiographic results were compared with those in a matched control group of 100 aneurysms treated solely with bare platinum coils. HydroCoil complication rates were compared to bare platinum coil rates at our institution and in published series. Results Adjuvant HydroCoil treatment led to increased mean percentage aneurysm filling compared to controls (50 ± 21% versus 27 ± 13%, P < 0.001). Immediate posttreatment angiographic results showed significantly (P < 0.001) more complete occlusions and fewer incomplete (<95%) occlusions compared to controls. Intermediate follow-up angiograms (median 7.5 months) in 63 aneurysms showed a trend towards fewer incomplete occlusions with HydroCoil treatment. There were significantly fewer major recurrences with HydroCoil treatment compared to the control treatment (9.5% versus 22.6%, P 0.046). In the adjuvant HydroCoil group, major recurrent aneurysms had significantly less percentage volume packing with HydroCoils than non-recurrent aneurysms (50.3 ± 5.0% versus 65.3 ± 18.0%, P = 0.04). There was a 12% procedural complication rate, 6% procedural morbidity and 1% mortality rate, similar to institutional and reported bare platinum coil complication rates.Conclusion HydroCoils can be safely deployed with a similar complication rate to bare platinum coils. They result in improved aneurysm filling. Intermediate follow-up angiography showed significantly fewer major recurrences. Long-term follow-up is required to confirm initial improved stability. (orig.)

  7. Caracterización química de la vidriera de Sant Pere i Sant Jaume (segundo cuarto del s. XIV, Monestir de Pedralbes, Barcelona

    Directory of Open Access Journals (Sweden)

    Gimeno, D.

    2002-04-01

    Full Text Available Several architectural medieval stained glass (1330 a.C. from Pedralbes monastery’s church (Barcelona, Spain have been characterised chemically. This note explains the results obtained with EMPA, representative of bulk chemistry of several coloured glasses (white, green, pink, blue, yellow, red coming from the Sant Pere and Sant Jaume stained-glass window. Most of them are Na-rich (13-19 % Na2O homogeneous in colour and composition, and show minor variations in bulk chemistry related with colour (i.e., CuO in the 1.6-6 % range in green glass. Singularly, red glass is K-rich (16.5 % K2O, 14 % CaO, and was elaborated in a way technologically more sophisticated (it is a plaqué glass, with a red Cu-rich layer sandwiched between a white transparent Cu-poor glass similar in composition. While Na-rich glasses are mostly unaltered, K-rich ones show moderate corrosion and partial loss of transparency. Dominance of Na-rich glasses in the stained glass windows (rare at that time, if we consider the present state of the art allowed an excellent conservation. Despite of the presence of mortar covering, patina, etc., bulk chemistry of the glass shows its value as a diagnostic tool in an early evaluation of the state of decay of an stained glass window.

    Se han caracterizado químicamente diferentes tipos de vidrios arquitectónicos originales de la iglesia del Monestir de Pedralbes, Barcelona (realizados hacia 1330. Esta nota expone los resultados obtenidos mediante el empleo de microsonda electrónica en vidrios de varios colores (blanco, verde, rosado, azul, amarillo, rojo de la vidriera de Sant Pere y Sant Jaume. Corresponden esencialmente a vidrios sódicos (dentro del rango 13-19 % de Na2O de coloración y composición homogénea, con elementos que actúan como colorante (p.e., CuO en rango 1.6-6 % en los vidrios verdes. El vidrio rojo, potásico, es una excepción notable (16.5 % K2O, 14 % CaO, tecnológicamente diferente (vidrio

  8. Toroidal field coils for the PDX machine

    International Nuclear Information System (INIS)

    Bushnell, C.W.

    1975-01-01

    This paper describes the engineering design features of the TF coils for the PDX machine. Included are design details of the electrical insulation, water cooling, and coil segment joint which allows access to the central machine area. A discussion of the problems anticipated in the manufacture and the planned solutions are presented

  9. Operator coil monitoring Acceptance Test Procedure

    International Nuclear Information System (INIS)

    Erhart, M.F.

    1995-01-01

    The readiness of the Data Acquisition and Control System (DACS) to provide monitoring and control of the Programmable Logic Controller (PLC) abort coils from the Master and RSS stations will be systematically tested during performance of this procedure. It should be noted that these are not physical abort coils but software coils controlled by the software's ladder logic. The readiness of the DACS to properly interface with the ENRAF wire level gauge installed in the SY-101 storage tank will also be tested. During this test, a verification of all abort coil indications will be conducted at the DACS Development Facility in the 306E Building by injecting an input signal for each DACS sensor that has an associated abort coil until the abort coil actuates, and then ensuring that the status of the abort coil indicated at the Master and RSS stations is correct. Each abort coil will also be tested to ensure that the ''ENABLE'' and ''DISABLE'' controls from the Master and RSS stations function correctly, and only with the use of proper passwords

  10. Coil Optimization for High Temperature Superconductor Machines

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Abrahamsen, Asger Bech

    2011-01-01

    This paper presents topology optimization of HTS racetrack coils for large HTS synchronous machines. The topology optimization is used to acquire optimal coil designs for the excitation system of 3 T HTS machines. Several tapes are evaluated and the optimization results are discussed. The optimiz...

  11. Novel transcranial magnetic stimulation coil for mice

    Science.gov (United States)

    March, Stephen; Stark, Spencer; Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) shows potential for non-invasive treatment of various neurological disorders. Significant work has been performed on the design of coils used for TMS on human subjects but few reports have been made on the design of coils for use on the brains of animals such as mice. This work is needed as TMS studies utilizing mice can allow rapid preclinical development of TMS for human disorders but the coil designs developed for use on humans are inadequate for optimal stimulation of the much smaller mouse brain. A novel TMS coil has been developed with the goal of inducing strong and focused electric fields for the stimulation of small animals such as mice. Calculations of induced electric fields were performed utilizing an MRI derived inhomogeneous model of an adult male mouse. Mechanical and thermal analysis of this new TMS helmet-coil design have also been performed at anticipated TMS operating conditions to ensure mechanical stability of the new coil and establish expected linear attraction and rotational force values. Calculated temperature increases for typical stimulation periods indicate the helmet-coil system is capable of operating within established medical standards. A prototype of the coil has been fabricated and characterization results are presented.

  12. The bar coil for NMR tomograph

    International Nuclear Information System (INIS)

    Bogorodzki, P.; Piatkowski, A.; Wasielewski, J.

    1995-01-01

    The bar coil (bi-planar) for the NMR tomograph, designed for medical diagnostics, has been described. The tests of coil shown that it generates good homogenous magnetic field in a big volume what results in improving of the signal-to-noise ratio

  13. Evidence-based pathology: umbilical cord coiling.

    Science.gov (United States)

    Khong, T Y

    2010-12-01

    The generation of a pathology test result must be based on criteria that are proven to be acceptably reproducible and clinically relevant to be evidence-based. This review de-constructs the umbilical cord coiling index to illustrate how it can stray from being evidence-based. Publications related to umbilical cord coiling were retrieved and analysed with regard to how the umbilical coiling index was calculated, abnormal coiling was defined and reference ranges were constructed. Errors and other influences that can occur with the measurement of the length of the umbilical cord or of the number of coils can compromise the generation of the coiling index. Definitions of abnormal coiling are not consistent in the literature. Reference ranges defining hypocoiling or hypercoiling have not taken those potential errors or the possible effect of gestational age into account. Even the way numerical test results in anatomical pathology are generated, as illustrated by the umbilical coiling index, warrants a critical analysis into its evidence base to ensure that they are reproducible or free from errors.

  14. Composite coils for toroidal field coils and method of using same

    International Nuclear Information System (INIS)

    Perkins, R. G.; Trujillo, S. M.

    1985-01-01

    A composite toroidal field (TF) generating means consisting of segmented magnetic coil windings is disclosed. Each coil winding of the TF generating means consists of a copper or copper alloy conductor segment and an aluminum or aluminum alloy conductor segment. The conductor segments are joined at a high strength, low electrical resistance joint and the joint may either be a mechanical or metallurgical one. The use of the aluminum or aluminum alloy conductor segments improves the neutron economy of the reactor with which the TF coil is associated and reduces TF coil nuclear heating and heating gradients, and activation in the TF coils

  15. Startup of Large Coil Test Facility

    International Nuclear Information System (INIS)

    Haubenreich, P.N.; Bohanan, R.E.; Fietz, W.A.; Luton, J.N.; May, J.R.

    1984-01-01

    The Large Coil Test Facility (LCTF) is being used to test superconducting toroidal field coils about one-third the size of those for INTOR. Eventually, six different coils from four countries will be tested. Operations began in 1983 with acceptance testing of the helium refrigerator/liquefier system. Comprehensive shakedown of the facility and tests with the first three coils (from Japan, the United States, and Switzerland) were successfully accomplished in the summer of 1984. Currents up to 10,200 A and fields up to 6.4 T were reached. Data were obtained on performance of refrigerator, helium distribution, power supplies, controls, and data acquisition systems and on the acoustic emission, voltages, currents, and mechanical strains during charging and discharging the coils

  16. Startup of Large Coil Test Facility

    International Nuclear Information System (INIS)

    Haubenreich, P.N.; Bohanan, R.E.; Fietz, W.A.; Luton, J.N.; May, J.R.

    1985-01-01

    The Large Coil Test Facility (LCTF) is being used to test superconducting toroidal field coils about one-third the size of those for INTOR. Eventually, six different coils from four countries will be tested. Operations began in 1983 with acceptance testing of the helium refrigerator/liquefier system. Comprehensive shakedown of the facility and tests with the first three coils (from Japan, the United States, and Switzerland) were successfully accomplished in the summer of 1984. Currents up to 10,200 A and fields up to 6.4 T were reached. Data were obtained on performance of refrigerator, helium distribution, power supplies, controls, and data acquisition systems and on the acoustic emission, voltages, currents, and mechanical strains during charging and discharging the coils

  17. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  18. Plan de mejora de la periferia de Terrassa: el caso del conjunto monumental de las iglesias de Sant Pere y su integración en el núcleo urbano

    OpenAIRE

    Gómez Val, Ricardo; Peig Ginabreda, Concepció

    2015-01-01

    Terrassa is nowadays a post-industria/ cíty ín the períphery of Barcelona. Since 2004 it has become the see of the new created bishop of Terrossa. lt existed once Jrom Vth to Vlllth but Jater disappeared and its see was held in Sant Pere1s monumental ensemble. Nowadays Ws not because it was considered to be far away from the city centre. This ensemble began a decadent process because it /ost ali political and geogrophical importance. At the end of the XXth century política/ ...

  19. Effects of passive coils on spheromak gross MHD instabilities

    International Nuclear Information System (INIS)

    Munson, C.; Janos, A.; Paul, S.; Wysocki, F.; Yamada, M.

    1983-01-01

    The experimental investigation of the effectiveness of figure-8 coils in stabilizing the n=1 tilting mode of spheromak plasmas in Proto S-1 A/B is extended. In addition, another coil configuration, the saddle coil, is examined

  20. Theoretical and computational studies of entangled rod-coil block copolymer diffusion

    Science.gov (United States)

    Wang, Muzhou; Alexander-Katz, Alfredo; Olsen, B. D.

    2012-02-01

    Despite continued interest in the thermodynamics of rod-coil block copolymers for functional nanostructured materials in organic electronics and biomaterials, relatively few studies have investigated the dynamics of these systems which are important for understanding diffusion, mechanics, and self-assembly kinetics. Here, the diffusion of coil-rod-coil block copolymers through entangled melts is simulated using the Kremer-Grest molecular dynamics model, demonstrating that the mismatch between the curvature of the rod and coil blocks results in dramatically slower reptation through the entanglement tube. For rod lengths near the tube diameter, this hindered diffusion is explained by a local curvature-dependent free energy penalty produced by the curvature mismatch, resulting in a rough energy surface as the rod moves along the tube contour. Compared to coil homopolymers which reptate freely along the tube, rod-coil block copolymers undergo an activated diffusion process which is considerably slower as the rod length increases. For large rods, diffusion of the rod through the tube only occurs when the coil blocks occupy straight entanglement tubes, which requires ``arm retraction'' as the dominant relaxation mechanism.

  1. A Built for Purpose Micro-Hole Coiled Tubing Rig (MCTR)

    Energy Technology Data Exchange (ETDEWEB)

    Bart Patton

    2007-09-30

    This report will serve as the final report on the work performed from the contract period October 2005 thru April 2007. The project 'A Built for Purpose Microhole Coiled Tubing Rig (MCTR)' purpose was to upgrade an existing state-of-the-art Coiled Tubing Drilling Rig to a Microhole Coiled Tubing Rig (MCTR) capable of meeting the specifications and tasks of the Department of Energy. The individual tasks outlined to meet the Department of Energy's specifications are: (1) Concept and development of lubricator and tool deployment system; (2) Concept and development of process control and data acquisition; (3) Concept and development of safety and efficiency improvements; and (4) Final unit integration and testing. The end result of the MCTR upgrade has produced a unit capable of meeting the following requirements: (1) Capable of handling 1-inch through 2-3/8-inch coiled tubing (Currently dressed for 2-3/8-inch coiled tubing and capable of running up to 3-1/2-inch coiled tubing); (2) Capable of drilling and casing surface, intermediate, production and liner hole intervals; (3) Capable of drilling with coiled tubing and has all controls and installation piping for a top drive; (4) Rig is capable of running 7-5/8-inch range 2 casing; and (5) Capable of drilling 5,000 ft true vertical depth (TVD) and 6,000 ft true measured depth (TMD).

  2. An alternative conformation of the gp41 heptad repeat 1 region coiled coil exists in the human immunodeficiency virus (HIV-1) envelope glycoprotein precursor

    International Nuclear Information System (INIS)

    Mische, Claudia C.; Yuan Wen; Strack, Bettina; Craig, Stewart; Farzan, Michael; Sodroski, Joseph

    2005-01-01

    The human immunodeficiency virus (HIV-1) transmembrane envelope glycoprotein, gp41, which mediates virus-cell fusion, exists in at least three different conformations within the trimeric envelope glycoprotein complex. The structures of the prefusogenic and intermediate states are unknown; structures representing the postfusion state have been solved. In the postfusion conformation, three helical heptad repeat 2 (HR2) regions pack in an antiparallel fashion into the hydrophobic grooves on the surface of a triple-helical coiled coil formed by the heptad repeat 1 (HR1) regions. We studied the prefusogenic conformation of gp41 by mutagenic alteration of membrane-anchored and soluble forms of the HIV-1 envelope glycoproteins. Our results indicate that, in the HIV-1 envelope glycoprotein precursor, the gp41 HR1 region is in a conformation distinct from that of a trimeric coiled coil. Thus, the central gp41 coiled coil is formed during the transition of the HIV-1 envelope glycoproteins from the precursor state to the receptor-bound intermediate

  3. High-resolution imaging of the spine in young infants with a loop-gap resonator remote current return coil

    International Nuclear Information System (INIS)

    Ball, W.S.; Prenger, E.C.; Auringer, S.T.

    1989-01-01

    MR imaging of the young child's spin requires proper selection of surface coils and pulse sequences that optimize resolution. The authors report the use in the infant spine of a new coil design in combination with specialized pulse sequences, such as fat suppression. Thirty children underwent spine MR imaging with a loop-gap resonator remote current return (RCR) coil. Spin-echo T1-weighted, T2-weighted, and T1-weighted fat-suppression pulse sequences were performed on a 1.5-T imager. Twelve patients had normal studies, 14 had spinal dysraphism, two had drop metastases, and two had paravertebral masses. Twelve initial patients had comparison images obtained with a 5-inch general-purpose surface coil. Similar pulse sequences were used for each coil. Image were compared diagnostically and for resolution based on the ability to discriminate small intrathecal structures

  4. Attenuation correction for flexible magnetic resonance coils in combined magnetic resonance/positron emission tomography imaging.

    Science.gov (United States)

    Eldib, Mootaz; Bini, Jason; Calcagno, Claudia; Robson, Philip M; Mani, Venkatesh; Fayad, Zahi A

    2014-02-01

    Attenuation correction for magnetic resonance (MR) coils is a new challenge that came about with the development of combined MR and positron emission tomography (PET) imaging. This task is difficult because such coils are not directly visible on either PET or MR acquisitions with current combined scanners and are therefore not easily localized in the field of view. This issue becomes more evident when trying to localize flexible MR coils (eg, cardiac or body matrix coil) that change position and shape from patient to patient and from one imaging session to another. In this study, we proposed a novel method to localize and correct for the attenuation and scatter of a flexible MR cardiac coil, using MR fiducial markers placed on the surface of the coil to allow for accurate registration of a template computed tomography (CT)-based attenuation map. To quantify the attenuation properties of the cardiac coil, a uniform cylindrical water phantom injected with 18F-fluorodeoxyglucose (18F-FDG) was imaged on a sequential MR/PET system with and without the flexible cardiac coil. After establishing the need to correct for the attenuation of the coil, we tested the feasibility of several methods to register a precomputed attenuation map to correct for the attenuation. To accomplish this, MR and CT visible markers were placed on the surface of the cardiac flexible coil. Using only the markers as a driver for registration, the CT image was registered to the reference image through a combination of rigid and deformable registration. The accuracy of several methods was compared for the deformable registration, including B-spline, thin-plate spline, elastic body spline, and volume spline. Finally, we validated our novel approach both in phantom and patient studies. The findings from the phantom experiments indicated that the presence of the coil resulted in a 10% reduction in measured 18F-FDG activity when compared with the phantom-only scan. Local underestimation reached 22% in

  5. Examination of measurement and its method of compensation of the sensitivity distribution using phased array coil for body scan

    CERN Document Server

    Kimura, T; Iizuka, A; Taniguchi, Y; Ishikuro, A; Hongo, T; Inoue, H; Ogura, A

    2003-01-01

    The influence on the quality of images by measurement of a sensitivity distribution and the use of a sensitivity compensation filter was considered using an opposite-type phased array coil and volume-type phased array coil. With the opposite-type phased array coil, the relation between coil interval and filter was investigated for the image intensity correction (IIC) filter, surface coil intensity correction (SCIC) filter (GE), and the Normalize filter (SIEMENS). The SCIC filter and Normalize filter showed distance dependability over the coil interval of signal-to-noise ratio (SNR) and uniformity was observed, and the existence of an optimal coil interval was suggested. Moreover, with the IIC filter, distance dependability over a coil interval was small, and the decrease in contrast with use was remarkable. On the other hand, with the volume-type phased array coil, the overlap of an array element was investigated to determine the influence it had on sensitivity distribution. Although the value stabilized in t...

  6. An Overview Of The ITER In-Vessel Coil Systems

    International Nuclear Information System (INIS)

    Heitzenroeder, P.J.; Brooks, A.W.; Chrzanowski, J.H.; Dahlgren, F.; Hawryluk, R.J.; Loesser, G.D.; Neumeyer, C.; Mansfield, C.; Smith, J.P.; Schaffer, M.; Humphreys, D.; Cordier, J.J.; Campbell, D.; Johnson, G.A.; Martin, A.; Rebut, P.H.; Tao, J.O.; Fogarty, P.J.; Nelson, B.E.; Reed, R.P.

    2009-01-01

    ELM mitigation is of particular importance in ITER in order to prevent rapid erosion or melting of the divertor surface, with the consequent risk of water leaks, increased plasma impurity content and disruptivity. Exploitable 'natural' small or no ELM regimes might yet be found which extrapolate to ITER but this cannot be depended upon. Resonant Magnetic Perturbation has been added to pellet pacing as a tool for ITER to mitigate ELMs. Both are required, since neither method is fully developed and much work remains to be done. In addition, in-vessel coils enable vertical stabilization and RWM control. For these reasons, in-vessel coils (IVCs) are being designed for ITER to provide control of Edge Localized Modes (ELMs) in addition to providing control of moderately unstable resistive wall modes (RWMs) and the vertical stability (VS) of the plasma.

  7. Investigation of cooling coil corrosion in storage tanks for radioactive waste

    International Nuclear Information System (INIS)

    Ondrejcin, R.S.

    1978-01-01

    The high frequency of cooling coil leaks observed in high-heat waste storage tanks soon after sludge removal operations is attributed to pitting, according to laboratory corrosion studies. Experiments show that the most likely series of events leading to coil leakage is (1) excessive dilution of basic nitrite in the supernate, (2) initiation of attack in crevices due to oxygen depletion cells, and (3) acceleration of the attack by sulfate dissolved from the sludge. When sludge was slurried with water, the interstitial liquid was diluted. Nitrite, the anodic inhibitor that prevented attack on coils and tanks in normal operation when its concentration was 0.5 to 3.0M, could accelerate attack when diluted to 10 -4 to 10 -3 M. Attack was presumably initiated at oxygen depletion cells. The presence of sulfate, leached from the sludge, produced a conductive solution that could produce high current densities at the corroding steel surface. The proposed series of events leading to coil leakage agrees with the observations previously made on one leaking coil removed from Tank 2F after sludge removal in 1967. Examination revealed pitting that had originated on the outside of the coils. This pitting was attributed to oxygen depletion cells in coil crevices. To prevent recurrence of pitting attack on cooling coils during future sludge removal operations, the sludge should be slurried (1) with waste diluted less than one hundredfold with water, or (2) with a 500-ppm nitrite-H 2 O solution at pH 12. Either method should preclude pitting damage to the coils

  8. Cartilage and bone neoformation in rabbit carotid bifurcation aneurysms after endovascular coil embolization

    Directory of Open Access Journals (Sweden)

    H Plenk

    2008-11-01

    Full Text Available Occurrence and histomorphology of cartilage and bone neoformations was retrospectively evaluated in rabbit experimental aneurysms after endovascular coil embolization. During product development, 115 carotid bifurcation aneurysms were treated with hydrogel-containing devices (HydroCoil®, n=77; HydroSoft®, n=28; prototype Hydrogel-only, n=10; MicroVentionTerumo, Aliso Viejo, CA. Additional 29 aneurysms were treated with standard (n=22 or with degradable polymer-covered (n=7 platinum coils. After 4 to 52 weeks, the retrieved aneurysms were methylmethacrylate embedded, and ground sections were surface-stained with Rapid Bone Stain and Giemsa solution. Cartilage and/or bone tissue was assessed by light microscopy; respective tissue areas in the aneurysms were determined by computerized histomorphometry. Cartilage neoformation was observed from 26 to 52 weeks. Single chondrocytes to hyaline or fibrous cartilage areas, occupying up to 29% of the aneurysm cavity, were found in 6 aneurysms, treated with HydroCoil (n=4, Hydrogel-only (n=1, and resorbable polymer (n=1 devices. Chondral ossification associated cartilage neoformation in 2 of these 4 HydroCoil-treated aneurysms. Membranous woven and lamellar bone ossicles were observed from 13 to 52 weeks in 7 aneurysms, treated with HydroCoil (n=3 and platinum coil (n=4 devices. Altogether, cartilage and/or bone neoformation was observed in 13 (9% of 144 rabbit bifurcation aneurysms treated with various embolic devices. Incidence was low until 26 weeks, but increased at 52 weeks in both, HydroCoil and standard platinum coil treated aneurysms. As the neoformations were predominantly located in proximity to the aneurysm neck, they could be related to the long-term mechanobiology of cell differentiation during fibrovascular healing of blood flow-exposed embolized aneurysms.

  9. Switching transients in a superconducting coil

    International Nuclear Information System (INIS)

    Owen, E.W.; Shimer, D.W.

    1983-01-01

    A study is made of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to performance tests on the MFTF Yin-yang coils. It is found that the breaker opening time is the critical factor in determining the size and shape of the transient. Instantaneous opening of the breaker causes a lightly damped transient with large amplitude voltages to ground. Increasing the opening time causes the transient to become a monopulse of decreasing amplitude. The voltages at the external terminals are determined by the parameters of the external circuit. For fast opening times the frequency depends on the dump resistor inductance, the circuit capacitance, and the amplitude on the coil current. For slower openings the dump resistor inductance and the current determine the amplitude of the voltage to ground at the terminals. Voltages to ground are less in the interior of the coil, where transients related to the parameters of the coil itself are observed

  10. Correcting coils in end magnets of accelerators

    Directory of Open Access Journals (Sweden)

    L. R. P. Kassab

    1998-05-01

    Full Text Available We present an empirical investigation of the correcting coils behavior used to homogenize the field distribution of the race-track microtron accelerator end magnets. These end magnets belong to the second stage of the 30.0 MeV cw electron accelerator under construction at IFUSP, the race-track microtron booster, in which the beam energy is raised from 1.97 to 5.1 MeV. The correcting coils are attached to the pole faces and are based on the inhomogeneities of the magnetic field measured. The performance of these coils, when operating the end magnets with currents that differ by ±10% from the one used in the mappings that originated the coils copper leads, is presented. For one of the magnets, adjusting conveniently the current of the correcting coils makes it possible to homogenize field distributions of different intensities, once their shapes are practically identical to those that originated the coils. For the other one, the shapes are changed and the coils are less efficient. This is related to intrinsic factors that determine the inhomogeneities. However, we obtained uniformity of 0.001% in both cases.

  11. Calculation of an axisymmetric current coil field with the bounding contour integration method

    Energy Technology Data Exchange (ETDEWEB)

    Telegin, Alexander P.; Klevets, Nickolay I. E-mail: pmsolution@mail.ru

    2004-06-01

    Method for the economic and stable (in the sense of calculation errors) analysis of an induction of a magnetic field created with axisymmetric coils in arbitrary points of space, including points located inside a coil or on its border, is obtained. The basic idea of the method is to replace a current coil with continuous distribution of current density by magnetization distributed in the volume of the coil and creating the equivalent magnetic field. This allows to use field surface sources at calculation of the fields. Consequently, the range of integration is reduced resulting in reduction of calculation volume by an order in most cases. Besides, the calculation of improper integrals in internal points and on the border is completely excluded.

  12. Calculation of an axisymmetric current coil field with the bounding contour integration method

    International Nuclear Information System (INIS)

    Telegin, Alexander P.; Klevets, Nickolay I.

    2004-01-01

    Method for the economic and stable (in the sense of calculation errors) analysis of an induction of a magnetic field created with axisymmetric coils in arbitrary points of space, including points located inside a coil or on its border, is obtained. The basic idea of the method is to replace a current coil with continuous distribution of current density by magnetization distributed in the volume of the coil and creating the equivalent magnetic field. This allows to use field surface sources at calculation of the fields. Consequently, the range of integration is reduced resulting in reduction of calculation volume by an order in most cases. Besides, the calculation of improper integrals in internal points and on the border is completely excluded

  13. Characterization and evaluation of a flexible MRI receive coil array for radiation therapy MR treatment planning using highly decoupled RF circuits

    Science.gov (United States)

    McGee, Kiaran P.; Stormont, Robert S.; Lindsay, Scott A.; Taracila, Victor; Savitskij, Dennis; Robb, Fraser; Witte, Robert J.; Kaufmann, Timothy J.; Huston, John, III; Riederer, Stephen J.; Borisch, Eric A.; Rossman, Phillip J.

    2018-04-01

    The growth in the use of magnetic resonance imaging (MRI) data for radiation therapy (RT) treatment planning has been facilitated by scanner hardware and software advances that have enabled RT patients to be imaged in treatment position while providing morphologic and functional assessment of tumor volumes and surrounding normal tissues. Despite these advances, manufacturers have been slow to develop radiofrequency (RF) coils that closely follow the contour of a RT patient undergoing MR imaging. Instead, relatively large form surface coil arrays have been adapted from diagnostic imaging. These arrays can be challenging to place on, and in general do not conform to the patient’s body habitus, resulting in sub optimal image quality. The purpose of this study is to report on the characterization of a new flexible and highly decoupled RF coil for use in MR imaging of RT patients. Coil performance was evaluated by performing signal-to-noise ratio (SNR) and noise correlation measurements using two coil (SNR) and four coil (noise correlation) element combinations as a function of coil overlap distance and comparing these values to those obtained using conventional coil elements. In vivo testing was performed in both normal volunteers and patients using a four and 16 element RF coil. Phantom experiments demonstrate the highly decoupled nature of the new coil elements when compared to conventional RF coils, while in vivo testing demonstrate that these coils can be integrated into extremely flexible and form fitting substrates that follow the exact contour of the patient. The new coil design addresses limitations imposed by traditional surface coil arrays and have the potential to significantly impact MR imaging for both diagnostic and RT applications.

  14. Routine phasing of coiled-coil protein crystal structures with AMPLE

    Directory of Open Access Journals (Sweden)

    Jens M. H. Thomas

    2015-03-01

    Full Text Available Coiled-coil protein folds are among the most abundant in nature. These folds consist of long wound α-helices and are architecturally simple, but paradoxically their crystallographic structures are notoriously difficult to solve with molecular-replacement techniques. The program AMPLE can solve crystal structures by molecular replacement using ab initio search models in the absence of an existent homologous protein structure. AMPLE has been benchmarked on a large and diverse test set of coiled-coil crystal structures and has been found to solve 80% of all cases. Successes included structures with chain lengths of up to 253 residues and resolutions down to 2.9 Å, considerably extending the limits on size and resolution that are typically tractable by ab initio methodologies. The structures of two macromolecular complexes, one including DNA, were also successfully solved using their coiled-coil components. It is demonstrated that both the ab initio modelling and the use of ensemble search models contribute to the success of AMPLE by comparison with phasing attempts using single structures or ideal polyalanine helices. These successes suggest that molecular replacement with AMPLE should be the method of choice for the crystallographic elucidation of a coiled-coil structure. Furthermore, AMPLE may be able to exploit the presence of a coiled coil in a complex to provide a convenient route for phasing.

  15. Internal trim coils for CBA superconducting magnets

    International Nuclear Information System (INIS)

    Thompson, P.A.; Aronson, S.; Cottingham, J.G.; Garber, M.; Hahn, H.; Sampson, W.B.

    1983-01-01

    In order to correct iron saturation effects and shape the beam working line, superconducting trim coils have been constructed, which operate inside the main coils. Detailed studies of mechanical properties, quench behavior, fields produced, and hysteresis have lead to the production of accelerator-quality coils generating the required-strength harmonics up to cos (7theta). These are routinely installed in CBA main magnets and operate at 80% of short sample with negligible training in an ambient field of more than 5.3T

  16. Superconducting coil development and motor demonstration: Overview

    Science.gov (United States)

    Gubser, D. U.

    1995-12-01

    Superconducting bismuth-cuprate wires, coils, and magnets are being produced by industry as part of a program to test the viability of using such magnets in Naval systems. Tests of prototype magnets, coils, and wires reveal progress in commercially produced products. The larger magnets will be installed in an existing superconducting homopolar motor and operated initially at 4.2K to test the performance. It is anticipated that approximately 400 Hp will be achieved by the motor. This article reports on the initial tests of the magnets, coils, and wires as well as the development program to improve their performance.

  17. CS model coil experimental log book

    International Nuclear Information System (INIS)

    Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi; Tsuji, Hiroshi

    2001-02-01

    Charging test of the ITER CS Model Coil which is the world's largest superconducting pulse coil and the CS Insert Coil had started at April 11, 2000 and had completed at August 18, 2000. In the campaign, total shot numbers were 356 and the size of the data file in the DAS (Data Acquisition System) was over 20 GB. This report is a database that consists of the log list and the log sheets of every shot. One can access the database, make a search, and browse results via Internet (http://1ogwww.naka.jaeri.go.jp). The database will be useful to quick search to choose necessary shots. (author)

  18. Large magnetic coils for fusion technology

    International Nuclear Information System (INIS)

    Komarek, P.; Ulbricht, A.

    1989-01-01

    This paper reviews the current status of research in this field and outlines future tasks and experiments for the Next European Torus (NET). Research and development work accomplished so far permits generation and safe operation of magnetic fields up to 9 T by means of NbTi coils. Fields up to 11 T are feasible if the coils are cooled with superfluid helium at 1.8 K. The potential of the Nb 3 Sn coils promise achievement of magnetic fields between 12 and 13 T. (MM) [de

  19. Design and Fabrication of the KSTAR Poloidal Field Coil Structure

    International Nuclear Information System (INIS)

    Park, H. K.; Choi, C. H.; Sa, J. W.

    2005-01-01

    The KSTAR magnet system consists of 16 toroidal field(TF) coils. 4 pairs of central solenoid(CS) coils, and 3 pairs of outer poloidal field(PF) coils. The TF coils are encased in a structure to enhance mechanical stability. The CS coil structure is supported on top of the TF coil structure and supplies a vertical compression of 15 MN to prevent lateral movement due to a repulsive force between the CS coils. The PF coil system is vertically symmetry to the machine mid-plane and consists of 6 coils and 80 support structures(i.e, 16 for PF5, 32 for PF6 and 32 fort PF7). All PF coil structures should absorb the thermal contraction difference between TF coil structure and PF coils due to cool down and endure the vertical and radial magnetic forces due to current charging. In order to satisfy these structural requirements. the PF5 coil structure is designed base on hinges and both of PF6 and PF7 coil structures based on flexible plates. The PF coil structures are assembled on the TF coil structure with an individual basement that is welded on the TF coil structure

  20. Flexible eddy current coil arrays

    International Nuclear Information System (INIS)

    Krampfner, Y.; Johnson, D.P.

    1987-01-01

    A novel approach was devised to overcome certain limitations of conventional eddy current testing. The typical single-element hand-wound probe was replaced with a two dimensional array of spirally wound probe elements deposited on a thin, flexible polyimide substrate. This provides full and reliable coverage of the test area and eliminates the need for scanning. The flexible substrate construction of the array allows the probes to conform to irregular part geometries, such as turbine blades and tubing, thereby eliminating the need for specialized probes for each geometry. Additionally, the batch manufacturing process of the array can yield highly uniform and reproducible coil geometries. The array is driven by a portable computer-based eddy current instrument, smartEDDY/sup TM/, capable of two-frequency operation, and offers a great deal of versatility and flexibility due to its software-based architecture. The array is coupled to the instrument via an 80-switch multiplexer that can be configured to address up to 1600 probes. The individual array elements may be addressed in any desired sequence, as defined by the software

  1. Electromagnetic-coil (EM-coil) measurement technique to verify presence of metal/absence of oxide attribute

    International Nuclear Information System (INIS)

    Fuller, J.L.; Hockey, R.L.

    2001-01-01

    range between 10 -6 and 10 -20 mhos/meter, while the metals and alloys typically span a range between 7x10 7 and 5x10 5 mhos/meter. Measurements have been made using materials spanning both ends of each range. The EM coil method operates on the basis of Faraday's Law of induction. An alternating low-voltage signal is applied to an encircling coil at a selected frequency, generating a magnetic field at a storage containers surface. An electric field, of the same frequency, is generated in all metal objects placed inside the coil. The intensity of this electric field diminishes with depth into a metal. This electric field then causes electric current (commonly referred to as eddy current) to flow throughout conductive objects. As these induced currents flow they also generate a secondary magnetic field causing the coils impedance to change in proportion to the total magnetic field passing through the coil. A high-precision, impedance measuring device can monitor the coil's impedance and thus obtain an electromagnetic signature for all conductive objects placed inside the coil. The EM-coil is inherently less intrusive than a radiation measurement since it is sensitive to the combination of configuration and composition. On a mathematical basis, component information cannot be extracted from this measurement because the coil impedance is a two-parameter quantity and the number of parameters affecting the coil impedance is much greater than two. The EM-coil method can make a determination that a container does or does not enclose metal in the expected configuration. Radiation detection methods on the other hand may only be able to establish the lack of oxide, which thereby implies the presence of metal, a weaker statement. The EM-coil data analysis is extremely simple, requiring the definition of a region of interest in a two- dimensional plot. The EM-coil method is able to make a measurement in less than a minute, whereas radiation measurement methods demonstrated to

  2. A coil test facility for the cryogenic tests of the JT-60SA TF coils

    International Nuclear Information System (INIS)

    Chantant, M.; Genini, L.; Bayetti, P.; Millet, F.; Wanner, M.; Massaut, V.; Corte, A. Della; Ardelier-Desage, F.; Catherine-Dumont, V.; Dael, A.; Decool, P.; Donati, A.; Duchateau, J.L.; Garibaldi, P.; Girard, S.; Hatchressian, J.C.; Fejoz, P.; Jamotton, P.; Jourdheuil, L.; Juster, F.P.

    2011-01-01

    In the framework of the Broader Approach Activities, the EU will deliver to Japan the 18 superconducting coils, which constitute the JT-60SA Toroidal field magnet. These 18 coils, manufactured by France and Italy, will be cold tested before shipping to Japan. For this purpose, the European Joint Undertaking for ITER, the Development of Fusion Energy ('Fusion for Energy', F4E) and the European Voluntary Contributors are collaborating to design and set-up a coil test facility (CTF) and to perform the acceptance test of the 18 JT-60SA Toroidal Field (TF) coils. The test facility is designed to test one coil at a time at nominal current and cryogenic temperature. The test of the first coil of each manufacturer includes a quench triggered by increasing the temperature. The project is presently in the detailed design phase.

  3. Coil measurement data acquisition and curing press control system for SSC dipole magnet coils

    International Nuclear Information System (INIS)

    Dickey, C.E.

    1989-03-01

    A coil matching program, similar in theory to the methods used to match Tevatron coils, is being developed at Fermilab. Modulus of elasticity and absolute coil size will be determined at 18-inch intervals along the coils while in the coil curing press immediately following the curing process. A data acquisition system is under construction to automatically acquire and manage the large quantities of data that result. Data files will be transferred to Fermilab's VAX Cluster for long-term storage and actual coil matching. The data acquisition system will also provide the control algorithm for the curing press hydraulic system. A description of the SSC Curing Press Data Acquisition and Controls System will be reported. 20 figs

  4. Entrevista a Jordi Borja, geógrafo y urbanista. Entrevista a Santiago Cirugeda, arquitecto. Entrevista a Pere Alcober, delegado de deportes del Ayuntamiento de Barcelona.

    Directory of Open Access Journals (Sweden)

    Francesc Magrinyà

    2008-03-01

    Full Text Available Jordi Borja, nacido en Barcelona, es geógrafo y urbanista. Entre sus publicaciones destaca Local y global, con Manuel Castells (1998, Barcelona, un modelo de transformación urbana (1995, El espacio público, ciudad y ciudadanía, con Zaida Muxi (2001 y La ciudad conquistada (Alianza, 2004. Dirige el Programa de Gestión de la Ciudad en la Universidad Abierta de Catalunya (UOC. Entre muchos otros temas, su interés por el concepto de ciudadanía y espacio público ha sido siempre una constante. La entrevista se realizó el 27 de mayo de 2007. Cuando Santiago Cirugeda aceptó realizar una entrevista para Apunts. Educación Física y Deportes, le propusimos que nos enviara un currículo de presentación a fin que pudiera ser conocido por las personas que la leyeran. He aquí unos fragmentos del mismo: “Estudié arquitectura en la ETSA de Sevilla, donde lo pasé muy bien. Finalmente acabé mi carrera en Barcelona. Desarrollo desde hace 10 años proyectos de subversión en distintos ámbitos de la realidad urbana que me ayuden a sobrellevar esta complicada vida social. Desde ocupaciones sistemáticas de espacios públicos con contenedores, hasta la construcción de prótesis en fachadas, patios, cubiertas e incluso en solares. Todo ello negociando entre la legalidad e ilegalidad, para recordar el enorme control al que estamos sometidos. Realizo proyectos de arquitectura, escribo artículos y participo en diferentes medios docentes y culturales (masters, seminarios, conferencias, workshops, exposiciones, etc... En 2007 presento el libro Situaciones Urbanas, que plantea estrategias legales y demandas, a través de proyectos arquitectónicos” Pere Alcober nos acoge en su despacho del Instituto Barcelona Esports (IBE del Ayuntamiento de Barcelona. El día de la entrevista, 27 de septiembre de 2007, el sol entra por las ventanas y fuera se ven árboles, jardines y el cielo azul. Hay mucha tranquilidad. Hablamos durante casi dos horas y no hay

  5. Design considerations for ITER toroidal field coils

    International Nuclear Information System (INIS)

    Kalsi, S.S.; Lousteau, D.C.; Miller, J.R.

    1987-01-01

    The International Thermonuclear Experimental Reactor (ITER) is a new tokamak design project with joint participation from Europe, Japan, the Union of Soviet Socialist Republics (U.S.S.R.), and the United States. This paper describes a magnetic and mechanical design methodology for toroidal field (TF) coils that employs Nb 3 Sn superconductor technology. Coil winding is sized by using conductor concepts developed for the U.S. TIBER concept. Manifold concepts are presented for the complete cooling system. Also included are concepts for the coil structural arrangement. The effects of in-plane and out-of-plane loads are included in the design considerations for the windings and case. Concepts are presented for reacting these loads with a minimum amount of additional structural material. Concepts discussed in this paper could be considered for the ITER TF coils

  6. 12 tesla test coil. Annual progress report

    International Nuclear Information System (INIS)

    1979-01-01

    The Plasma Fusion Center at MIT has been charged with responsibility for the design, development, fabrication and test operation of a Niobium-3-Tin Superconducting Test Coil. Research is described on DOE's 12 tesla coil demonstration program in which several one-meter diameter superconducting test coils will be inserted and tested in DOE's High Field Test Facility at the Lawrence Livermore Laboratories. The work was initiated at the start of FY 79. FY 79 saw the completion of our Preliminary Design and the initiation of three (3) subcontracts: (1) Westinghouse review of the Preliminary Design, (II) Supercon, Inc. development of a tubular copper matrix, Nb 3 Sn Superconductor and (III) Airco optimization of the LCP-W Nb 3 Sn superconductor for 12T service. In addition, Airco was charged with the production of a 1000 foot length of model 15,000A conductor. Coil winding exercises were initiated at the Everson Electric Company

  7. OCLATOR (One Coil Low Aspect Toroidal Reactor)

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, S.

    1980-02-01

    A new approach to construct a tokamak-type reactor(s) is presented. Basically the return conductors of toroidal field coils are eliminated and the toroidal field coil is replaced by one single large coil, around which there will be placed several tokamaks or other toroidal devices. The elimination of return conductors should, in addition to other advantages, improve the accessibility and maintainability of the tokamaks and offer a possible alternative to the search for special materials to withstand large neutron wall loading, as the frequency of changeover would be increased due to minimum downtime. It also makes it possible to have a low aspect ratio tokamak which should improve the ..beta.. limit, so that a low toroidal magnetic field strength might be acceptable, meaning that the NbTi superconducting wire could be used. This system is named OCLATOR (One Coil Low Aspect Toroidal Reactor).

  8. Advanced Singlet Oxygen Generator for a COIL

    National Research Council Canada - National Science Library

    Kodymova, Jarmila; Zagidullin, M; Nikolaev, V; Svistun, M; Khvatov, N; Hruby, J; Spalek, O; Jirasek, V; Censsky, M

    2005-01-01

    This report results from a contract tasking Academy of Sciences as follows: The Grantee will develop new and radically different ideas for a high performance, advanced singlet oxygen generator for driving a supersonic COIL...

  9. Helium leak testing the Westinghouse LCP coil

    International Nuclear Information System (INIS)

    Merritt, P.A.; Attaar, M.H.; Hordubay, T.D.

    1983-01-01

    The tests, equipment, and techniques used to check the Westinghouse LCP coil for coolant flow path integrity and helium leakage are unique in terms of test sensitivity and application. This paper will discuss the various types of helium leak testing done on the LCP coil as it enters different stages of manufacture. The emphasis will be on the degree of test sensitivity achieved under shop conditions, and what equipment, techniques and tooling are required to achieve this sensitivity (5.9 x 10 -8 scc/sec). Other topics that will be discussed are helium flow and pressure drop testing which is used to detect any restrictions in the flow paths, and the LCP final acceptance test which is the final leak test performed on the coil prior to its being sent for testing. The overall allowable leak rate for this coil is 5 x 10 -6 scc/sec. A general evaluation of helium leak testing experience are included

  10. Radiative MRI Coil Design Using Parasitic Scatterers

    DEFF Research Database (Denmark)

    Sanchez-Heredia, Juan D.; Avendal, Johan; Bibic, Adnan

    2018-01-01

    allows for antenna design techniques to be adapted to RF coil designs. This study proposes the use of parasitic scatterers to improve the performance of an existing 7T MRI coil called the single-sided adapted dipole (SSAD) antenna. The results reveal that scatterers arranged in a Yagi fashion can......Conventionally, radiofrequency (RF) coils used for magnetic resonance imaging (MRI) are electrically small and designed for nearfield operation. Therefore, existing antenna design techniques are mostly irrelevant for RF coils. However, the use of higher frequencies in ultrahigh field (UHF) MRI...... be applied to reduce local specific absorption rate (SAR) maxima of a reference SSAD by 40% with only a 6% decrease in the propagated B1 + field at the tissue depth of 15 cm. The higher directivity of the proposed design also decreasing the coupling with additional elements, making this antenna...

  11. MR angiography after coiling of intracranial aneurysms

    NARCIS (Netherlands)

    Schaafsma, J.D.

    2012-01-01

    Introduction Endovascular occlusion with detachable coils has become an alternative treatment to neurosurgical clipping of intracranial aneurysms over the last two decades. Its minimal invasiveness is the most important advantage of this treatment compared to clipping. The disadvantage of occlusion

  12. Poloidal field coil design for known plasma equilibrium states

    International Nuclear Information System (INIS)

    Paulson, C.C.; Todd, A.M.M.; Reusch, M.F.

    1986-01-01

    The technique for obtaining plasma equilibria with given boundary conditions has long been known and understood. The inverse problem of obtaining a poloidal field (PF) coil system from a given plasma equilibrium has been widely studied, however its solution has remained largely an art form. An investigation, by the writers, of this fundamentally ill-posed inverse problem has resulted in a new understanding of the requirements that solutions must satisfy. A set of interacting computer codes has been written which may be used to successfully design PF coil systems capable of supporting given plasma equilibria. It is shown that for discrete coil systems with a reasonable number of elements the standard minimization of the R M S flux error can lead to undesirable results. Examples are given to show that an additional stability requirement must be imposed on the regularization parameter to obtain correct solutions. For some equilibria, the authors find that the inverse problem admits dual solutions corresponding to two possible magnetic field configurations that fit the constraining relations on the plasma surface equally well. An additional minimization of the absolute value of the limiter flux is required to discriminate between these solutions

  13. Thermodynamic analysis of cavity creating mutations in an engineered leucine zipper and energetics of glycerol-induced coiled coil stabilization.

    Science.gov (United States)

    Dürr, E; Jelesarov, I

    2000-04-18

    Protein stability in vitro can be influenced either by introduction of mutations or by changes in the chemical composition of the solvent. Recently, we have characterized the thermodynamic stability and the rate of folding of the engineered dimeric leucine zipper A(2), which has a strengthened hydrophobic core [Dürr, E., Jelesarov, I., and Bosshard, H. R. (1999) Biochemistry 38, 870-880]. Here we report on the energetic consequences of a cavity introduced by Leu/Ala substitution at the tightly packed dimeric interface and how addition of 30% glycerol affects the folding thermodynamics of A(2) and the cavity mutants. Folding could be described by a two-state transition from two unfolded monomers to a coiled coil dimer. Removal of six methylene groups by Leu/Ala substitutions destabilized the dimeric coiled coil by 25 kJ mol(-1) at pH 3.5 and 25 degrees C in aqueous buffer. Destabilization was purely entropic at around room temperature and became increasingly enthalpic at elevated temperatures. Mutations were accompanied by a decrease of the unfolding heat capacity by 0.5 kJ K(-1) mol(-1). Addition of 30% glycerol increased the free energy of folding of A(2) and the cavity mutants by 5-10 kJ mol(-1) and lowered the unfolding heat capacity by 25% for A(2) and by 50% for the Leu/Ala mutants. The origin of the stabilizing effect of glycerol varied with temperature. Stabilization of the parent leucine zipper A(2) was enthalpic with an unfavorable entropic component between 0 and 100 degrees C. In the case of cavity mutants, glycerol induced enthalpic stabilization below 50 degrees C and entropic stabilization above 50 degrees C. The effect of glycerol could not be accounted for solely by the enthalpy and entropy of transfer or protein surface from water to glycerol/water mixture. We propose that in the presence of glycerol the folded coiled coil dimer is better packed and displays less intramolecular fluctuations, leading to enhanced enthalpic interactions and to an

  14. Magnetic Test Facility - Sensor and Coil Calibrations

    Science.gov (United States)

    2013-08-01

    amplitude of signals induced into the sensor. 2.1.1.2 Fluxgate magnetometers Fluxgate sensors consist of a ferromagnetic core, around which drive and sense...kHz range to be measured. Fluxgate magnetometers do not have a lower limit to their fre- quency response, and hence can be used to measure...placed within a larger triaxial coil which is used in conjunction with a fluxgate magnetometer to cancel earth’s field at the cen- tre of the coil. A

  15. Quadruple Cone Coil with improved focality than Figure-8 coil in Transcranial Magnetic Stimulation

    Science.gov (United States)

    Rastogi, Priyam; Lee, Erik G.; Hadimani, Ravi L.; Jiles, David C.

    Transcranial Magnetic Stimulation (TMS) is a non-invasive therapy which uses a time varying magnetic field to induce an electric field in the brain and to cause neuron depolarization. Magnetic coils play an important role in the TMS therapy since their coil geometry determines the focality and penetration's depth of the induced electric field in the brain. Quadruple Cone Coil (QCC) is a novel coil with an improved focality when compared to commercial Figure-8 coil. The results of this newly designed QCC coil are compared with the Figure-8 coil at two different positions of the head - vertex and dorsolateral prefrontal cortex, over the 50 anatomically realistic MRI derived head models. Parameters such as volume of stimulation, maximum electric, area of stimulation and location of maximum electric field are determined with the help of computer modelling of both coils. There is a decrease in volume of brain stimulated by 11.6 % and a modest improvement of 8 % in the location of maximum electric field due to QCC in comparison to the Figure-8 coil. The Carver Charitable Trust and The Galloway Foundation.

  16. An analysis of 3D solvation structure in biomolecules: application to coiled coil serine and bacteriorhodopsin.

    Science.gov (United States)

    Hirano, Kenji; Yokogawa, Daisuke; Sato, Hirofumi; Sakaki, Shigeyoshi

    2010-06-17

    Three-dimensional (3D) solvation structure around coiled coil serine (Coil-Ser) and inner 3D hydration structure in bacteriorhodopsin (bR) were studied using a recently developed method named multicenter molecular Ornstein-Zernike equation (MC-MOZ) theory. In addition, a procedure for analyzing the 3D solvent distribution was proposed. The method enables us to calculate the coordination number of solvent water as well as the strength of hydrogen bonding between the water molecule and the protein. The results for Coil-Ser and bR showed very good agreement with the experimental observations.

  17. Study for Manufacturing of ITER TF Coil Radial Plates

    International Nuclear Information System (INIS)

    Fietz, W.H.; Muetzel, W.

    2006-01-01

    During the previous design phase of ITER the ITER Toroidal Field Model Coil (TFMC) has been built to verify the TF coil concept of ITER and to proof the feasibility of an industrial fabrication of such a coil. In April 2004, Forschungszentrum and BNG, started a Manufacturing Study for the full scale Radial Plates (RP) of the TF Coils in the frame of an EFDA task. The main part of the Study was to develop feasible concepts of the technology for the manufacturing of the Full Scale Radial Plates starting with the raw material until final testing. The Feasibility Study has covered all manufacturing steps that are necessary for production of the RP. It has included as well a basic layout for the manufacturing process. During the work several proposals for the single manufacturing work steps have been developed. After that an evaluation of the found proposals has taken place. The most feasible proposals have been combined to manufacturing concepts. Finally two main Concepts were elaborated and evaluated: Concept 1 includes the premachining of segments with grooves, the welding of the segments and the final machining of the RP. Concept 2 includes the welding of not machined small segments to the D-shape of the RP and the following machining of the surface and grooves. Both Concepts will be described in detail with a comparison of tooling and manufacturing details, achievement of technological requirements as well as with the requirements coming from the overall time schedule. Based on the results of the assessment of the different concepts and manufacturing techniques Concept 1 shows some advantages compared to Concept 2. These will be described in the paper. In addition a proposal about additional R(and)D in front of the later manufacturing will be made. (author)

  18. Anomalies in the coil-stretch transition of flexible polymers

    Science.gov (United States)

    Ghosal, Aishani; Cherayil, Binny J.

    2018-03-01

    The flow-induced coil-stretch transition of high molecular weight polymers has generally been held to be of first order. But evidence of significant slowing down in the rate at which the polymers relax to equilibrium in the vicinity of the transition suggests that the thermodynamic character of the transition may be less clear-cut. The above slowing down effect is actually characteristic of a second-order transition, and it points to the existence of a broad spectrum of conformational states in the transition region, analogous to the existence of fluctuations of all length scales at a critical point. In this paper, using a path integral approach based on a free-draining finitely extensible chain model, we calculate various polymer properties as a function of elongational flow as a way of exploring different statistical mechanical details of the coil-stretch transition. These properties include the molecular weight dependence of the flow-extension curve of the polymer, the distribution of its steady-state end-to-end distances, and the characteristic relaxation time τR of these distances. Among other findings, our calculations indicate that the coil-stretch transition is discontinuous in the N → ∞ limit, that the effective free energy of the chain is unimodal at all values of the flow, becoming broad and flat in the immediate vicinity of the transition, and that the ratio of τR to the Rouse relaxation time increases abruptly at the transition before eventually reaching a plateau value at large flow strengths. These aspects of the coil-stretch transition place it among a larger class of unconventional nominally first-order single chain transitions that include the adsorption transition of surface-tethered polymers and the escape transition of compressed polymers.

  19. Thomson's Jumping Ring over a Long Coil

    Science.gov (United States)

    Jeffery, Rondo N.; Amiri, Farhang

    2018-01-01

    The classic jumping ring apparatus consists of a coil with an iron core that extends out of the coil. A copper or aluminum ring placed over the iron core jumps upward when AC power is applied to the coil. In this paper we will examine a modified design of the jumping ring apparatus, called the "long-coil design." It allows the ring to…

  20. COMPASS magnetic field coils and structure systems

    International Nuclear Information System (INIS)

    Crossland, R.T.; Booth, J.A.; Hayward, R.J.; Keogh, P.; Pratt, A.P.

    1987-01-01

    COMPASS is a new experimental toroidal assembly of compact design and with a wide range of physics objectives. It is required to operate either as a Tokamak or as a Reversed Field Pinch with interchangeable circular and dee-section vacuum vessels. The Toroidal field is produced by 16 rectangular coils of 4 turns with tapered conductors on the inside which nest together to form a vault to resist the centering forces. The coils are designed to produce a maximum field on axis of 2.1T which requires a current of 91 kA per turn. Two central solenoids and five pairs of coils symmetrically positioned above and below the machine equator provide the poloidal field. Both coil systems are supported form a mechanical support structure which surrounds the machine. This is primarily designed to resist out-of-plane forces on the TF coils but also acts as the base support for the PF coils and vacuum vessels. An illustration of the COMPASS Load Assembly is given and shows the D-shaped vacuum vessel, the major components and the various field windings

  1. Embroidered Coils for Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Michael I. Newton

    2013-04-01

    Full Text Available Magnetic resonance imaging is a widely used technique for medical and materials imaging. Even though the objects being imaged are often irregularly shaped, suitable coils permitting the measurement of the radio-frequency signal in these systems are usually made of solid copper. One problem often encountered is how to ensure the coils are both in close proximity and conformal to the object being imaged. Whilst embroidered conductive threads have previously been used as antennae in mobile telecommunications applications, they have not previously been reported for use within magnetic resonance. In this paper we show that an embroidered single loop coil can be used in a commercial unilateral nuclear magnetic resonance system as an alternative to a solid copper. Data is presented showing the determination of both longitudinal (T1 and effective transverse (T2eff relaxation times for a flat fabric coil and the same coil conformed to an 8 cm diameter cylinder. We thereby demonstrate the principles required for the wider use of fabric based conformal coils within nuclear magnetic resonance and magnetic resonance imaging.

  2. Dual levitated coils for antihydrogen production

    Science.gov (United States)

    Wofford, J. D.; Ordonez, C. A.

    2013-04-01

    Two coaxial superconducting magnetic coils that carry currents in the same direction and that are simultaneously levitated may serve for antihydrogen plasma confinement. The configuration may be suitable for use by a collaboration at the CERN Antiproton Decelerator facility to test fundamental symmetries between the properties of hydrogen and antihydrogen. Nested Penning traps are currently used to confine recombining antihydrogen plasma. Symmetry studies require the production of sufficiently cold antihydrogen. However, plasma drifts within nested Penning traps can increase the kinetic energy of antiprotons that form antihydrogen atoms. Dual levitated coils may serve to confine relatively large, cold, dense non-drifting recombining antihydrogen plasmas. A minimum-B magnetic field that is produced by the coils could provide for atom trapping. A toroidal plasma is confined between the coils. High density plasmas may be possible, by allowing plasma pressure to balance mechanical pressure to keep the coils apart. Progress is reported on theoretical and experimental efforts. The theoretical effort includes the development of a classical trajectory Monte Carlo simulation of confinement. The experimental effort includes levitation of a NdFeB permanent ring magnet, which produces a magnetic field that is qualitatively similar to the field that would be produced by the two coaxial superconducting magnetic coils. Liquid-nitrogen-cooled Bi-2223 high-temperature-superconducting components, with a critical temperature of 108 K, were used to levitate the ring magnet. An issue concerning keeping the plane of the levitated ring horizontal is discussed.

  3. Ressenya a Carme Llanes, L’obrador de Pere Nicolau, L’estil gòtic internacional a València (1390- 1408, València, Publicacions de la Universitat de València, 2014, pp. 312, ISBN: 978-84-370-9561-5

    Directory of Open Access Journals (Sweden)

    Guillem Chismol

    2015-12-01

    Full Text Available Review to Carme Llanes, L’obrador de Pere Nicolau, L’estil gòtic internacional a València (1390-1408, València, Publicacions de la Universitat de València, 2014, pp. 312, ISBN: 978-84-370-9561-5

  4. Three-dimensional finite element magnetic simulation of an innovative multi-coiled magnetorheological brake

    Science.gov (United States)

    Ubaidillah; Permata, A. N. S.; Mazlan, S. A.; Tjahjana, D. D. D. P.; Widodo, P. J.

    2017-10-01

    This research delivers a finite element magnetic simulation of a novel disk type multi-coil magnetorheological brake (MR brake). The MR brake axial design had more than one coil located outside of the casing. This design could simplify the maintenance process of brakes. One pair of coils was used as the representative of the entire coil in the simulation process, and it could distribute magnetic flux in all parts of the electromagnetic. The objective of this simulation was to produce magnetic flux on the surface of the disc brake rotor. The value of the MR brake magnetic flux was higher than that of the current MR brake having one coil with a larger size. The result of the simulation would be used to identify the effect of different fluids on each variation. The Magneto-rheological fluid MRF-132DG and MRF-140CG were injected in each gap as much as 0.50, 1.00, and 1.50 mm, respectively. On the simulation process, the coils were energized at 0.25, 0.50, 0.75, 1.00, 1.50, and 2.00 A, respectively. The magnetic flux produced by MRF-140CG was 336 m Tesla on the gap of 0.5 mm. The result of the simulation shows that the smaller the gap variation was, the higher the magnetic value was.

  5. Control of tokamak plasma current and equilibrium with hybrid poloidal field coils

    International Nuclear Information System (INIS)

    Shimada, Ryuichi

    1982-01-01

    A control method with hybrid poloidal field system is considered, which comprehensively implements the control of plasma equilibrium and plasma current, those have been treated independently in Tokamak divices. Tokamak equilibrium requires the condition that the magnetic flux function value on plasma surface must be constant. From this, the current to be supplied to each coil is determined. Therefore, each coil current is the resultant of the component related to plasma current excitation and the component required for holding equilibrium. Here, it is intended to show a method by which the current to be supplied to each coil can easily be calculated by the introduction of hybrid control matrix. The text first considers the equilibrium of axi-symmetrical plasma and the equilibrium magnetic field outside plasma, next describes the determination of current using the above hybrid control matrix, and indicates an example of controlling Tokamak plasma current and equilibrium by the hybrid poloidal field coils. It also shows that the excitation of plasma current and the maintenance of plasma equilibrium can basically be available with a single power supply by the appropriate selection of the number of turns of each coil. These considerations determine the basic system configuration as well as decrease the installed capacity of power source for the poloidal field of a Tokamak fusion reactor. Finally, the actual configuration of the power source for hybrid poloidal field coils is shown for the above system. (Wakatsuki, Y.)

  6. HydroSoft coil versus HydroCoil for endovascular aneurysm occlusion study: A single center experience

    International Nuclear Information System (INIS)

    Guo Xinbin; Fan Yimu; Zhang Jianning

    2011-01-01

    Background and purpose: The HydroCoil Embolic System (HES) was developed to reduce recurrences of aneurysms relative to platinum coils. But the HydroCoil Embolic System was characterized with many limitations. The manufacturer had recognized the challenge and recently a new design of hydrogel-coated coil-HydroSoft has become available in the market as the new generation HydroCoil. We reported our initial experience using HydroSoft coil versus HydroCoil in our center. Methods: 75 aneurysms embolized primarily using HydroSoft Coils from July 2008 to May 2009 were compared with 66 volume- and shape-matched aneurysms treated with HydroCoils from March 2006 to August 2008. Outcome measures included length and number of coils used, contrast volume, and length of hospital stay. During embolization, a stable framework was first established with bare coils, and hydrogel-coated coils were used subsequently to increase the packing density. Follow-up angiographic results 6 months after treatment were evaluated among some of the patients. Results: Successful coil embolization was achieved in all patients. There were no differences in average total coil length used per aneurysm. There were no differences in length of hospital stay and packing density. HydroSoft coils were more suitable using as the finishing or final coil. HydroSoft coil decreased the procedure-related retreated rates, and aneurysm packing was finished with soft, flexible HydroSoft coil and decreased the neck remnant rates. Follow-up angiography in HydroSoft-treated patients at 6 months revealed aneurysm stability without significant residual neck. Conclusions: HydroSoft coil allowed us to deploy coated coils with good packing density. A slight expansion of these coils at the neck can be expected to reduce neck remnant and potentially inhibit recurrence.

  7. EXPERIMENTAL INVESTIGATION OF THE CONVECTIVE HEAT TRANSFER IN A SPIRALLY COILED CORRUGATED TUBE WITH RADIANT HEATING

    Directory of Open Access Journals (Sweden)

    Milan Đorđević

    2017-12-01

    Full Text Available The Archimedean spiral coil made of a transversely corrugated tube was exposed to radiant heating in order to represent a heat absorber of the parabolic dish solar concentrator. The main advantage of the considered innovative design solution is a coupling effect of the two passive methods for heat transfer enhancement - coiling of the flow channel and changes in surface roughness. The curvature ratio of the spiral coil varies from 0.029 to 0.234, while water and a mixture of propylene glycol and water are used as heat transfer fluids. The unique focus of this study is on specific boundary conditions since the heat flux upon the tube external surfaces varies not only in the circumferential direction, but in the axial direction as well. Instrumentation of the laboratory model of the heat absorber mounted in the radiation field includes measurement of inlet fluid flow rate, pressure drop, inlet and outlet fluid temperature and 35 type K thermocouples welded to the coil surface. A thermal analysis of the experimentally obtained data implies taking into consideration the externally applied radiation field, convective and radiative heat losses, conduction through the tube wall and convection to the internal fluid. The experimental results have shown significant enhancement of the heat transfer rate compared to spirally coiled smooth tubes, up to 240% in the turbulent flow regime.

  8. Structured Light-Based Motion Tracking in the Limited View of an MR Head Coil

    DEFF Research Database (Denmark)

    Erikshøj, M.; Olesen, Oline Vinter; Conradsen, Knut

    2013-01-01

    A markerless motion tracking (MT) system developed for use in PET brain imaging has been tested in the limited field of view (FOV) of the MR head coil from the Siemens Biograph mMR. The system is a 3D surface scanner that uses structured light (SL) to create point cloud reconstructions of the fac......A markerless motion tracking (MT) system developed for use in PET brain imaging has been tested in the limited field of view (FOV) of the MR head coil from the Siemens Biograph mMR. The system is a 3D surface scanner that uses structured light (SL) to create point cloud reconstructions...

  9. Versatile fill coils: initial experience as framing coils for oblong aneurysms. A technical case report.

    Science.gov (United States)

    Osanai, Toshiya; Bain, Mark; Hui, Ferdinand K

    2014-01-01

    Coil embolization of oblong aneurysms is difficult because the majority of commercially available coils are manufactured with a helical or spherical tertiary structure. While adopting framing strategies for oblong aneurysms (aspect ratio ≥ 2: 1), traditional coils may be undersized in the long axis but oversized in the short axis, resulting in increased aneurysmal wall stress, risk of re-rupture, and difficulty creating a basket that respects the aneurysmal neck. We review three cases in which versatile filling coils (VFCs) were used as the initial coils for embolization of oblong aneurysms and report coil distribution characteristics and clinical outcomes. Packing density after VFC implantation was assessed using the software AngioSuite-Neuro edition and AngioCalc. a 58-year-old woman experienced a subarachnoid hemorrhage from a ruptured anterior communicating artery aneurysm (7.5 mm × 3.5 mm). A 3-6 mm × 15 cm VFC was selected as the first coil because the flexibility of its wave-loop structure facilitates framing of an irregularly shaped aneurysm. The loop portions of the structures tend to be pressed to the extremes of the aneurysmal sac by the wave component. The VFC was introduced smoothly into the aneurysmal sac without catheter kickback. We were then able to insert detachable filling coils without any adjunctive technique and achieved complete occlusion. Complete occlusion without severe complications was achieved in all three cases in our study. Average packing density after the first coil was 15.63%. VFC coils may have a specific role in framing oblong aneurysms given their complex loop-wave design, allowing spacing of the coils at the dome and neck while keeping sac stress to a minimum.

  10. Surgical management of an ACM aneurysm eight years after coiling.

    Science.gov (United States)

    Pogády, P; Fellner, F; Trenkler, J; Wurm, G

    2007-04-01

    The authors present a case report on rebleeding of a medial cerebral aneurysm (MCA) eight years after complete endovascular coiling. The primarily successfully coiled MCA aneurysm showed a local regrowth which, however, was not the source of the rebleeding. The angiogram demonstrated no evidence of contrast filling of the coiled segment, but according to intraoperative findings (haematoma location, displacement of coils, evident place of rupture) there is no doubt that the coiled segment of the aneurysm was responsible for the haemorrhage.

  11. Three-axis orthogonal transceiver coil for eddy current sounding

    Science.gov (United States)

    Sukhanov, D.; Zavyalova, K.; Goncharik, M.

    2017-08-01

    We propose the new structure of three-axis transceiver magnetic-induction coil for eddy current probing. Due to the orientation of the coils, the direct signal from the transmitting coil to the receiving coil is minimized, which provided a high dynamic range. Sensitivity in all directions is provided by combining coils of different orientations. Numerical simulation and experimental studies of such a system have been carried out and confirmed the applicability of the proposed method and the mathematical model.

  12. Using a wire coil insert for biodiesel production enhancement in a microreactor

    International Nuclear Information System (INIS)

    Aghel, Babak; Rahimi, Masoud; Sepahvand, Arash; Alitabar, Mohammad; Ghasempour, Hamid Reza

    2014-01-01

    Graphical abstract: Schematic view of microreactor system. - Highlights: • A wire coil insert was used to promote mixing in a biodiesel microreactor. • Advantages of using the wire coil in the microreactor over plain one are shown. • A yield of 99% was obtained in the modified microreactor after 180 s. • RSM and the Box–Behnken method were used to optimize the biodiesel production. • Advantages of using this system over other conventional reactors are illustrated. - Abstract: In the present work, the application of wire coil to promote mixing in a microreactor during continuous production of biodiesel was studied. For this aim, soybean oil as a feedstock and potassium hydroxide as a homogeneous catalyzed were used. The influences of the various parameters such as geometric and operational conditions on the performance of biodiesel production were experimentally examined. Response surface methodology (RSM) in conjunction with the Box–Behnken method was used to statistically analyze and optimize the biodiesel production process. The comparison between two types of reactors (with and without wire coil) shows a significant enhancement in mixing during transesterification. The impacts of different wire coil lengths and wire coil pitchs on methyl ester conversion were also investigated. A reaction yield of 99% at the residence time of 180 s was obtained in the modified microreactor. However, the measured pressure drop show that the microreactor equipped with wire coil consumed more energy. Therefore, performance ratio was defined to evaluate energy efficiency and the results show the advantage of using the wire coil insert in lower feed flow rates

  13. Gradient coil system for nuclear magnetic resonance apparatus

    International Nuclear Information System (INIS)

    Frese, G.; Siebold, H.

    1984-01-01

    A gradient coil system for an image-generating, nuclear magnetic resonance tomographic apparatus, particularly a zeugmatographic apparatus. The gradient coil system is arranged on a support body of rotational symmetry, illustratively a hollow cylindrical support body, having an axis which extends along the z-direction of an x, y, z coordinate system which has an origin in the center of imaging region. The gradient coil system contains two pairs of toroidal individual coils which are arranged symmetrically with respect to an x-y plane which extends through the center of the imaging region and which are arranged perpendicular to the z-axis. The direction of current flow in the individual coils of a coil pair is opposite to the direction of flow in the individual coils of the other coil pair. Moreover, further sets of coils are provided for generating field gradient Gx in the x-direction, and Gy in the y-direction. The hollow cylindrical shape of the support body on which the individual coils are arranged permit an imaging region having a substantially spherical volume with a substantially constant field gradient Gz to be achieved. Each of the coils has a predetermined linkage factor which corresponds to the product of the current flowing through the number of coil turns of the coil. Those coils which are arranged further from the plane of symmetry have a substantially larger linkage factor than the coils which are nearer to the plane of symmetry

  14. Graphene-coated coupling coil for AC resistance reduction

    Science.gov (United States)

    Miller, John M

    2014-03-04

    At least one graphene layer is formed to laterally surround a tube so that the basal plane of each graphene layer is tangential to the local surface of the tube on which the graphene layer is formed. An electrically conductive path is provided around the tube for providing high conductivity electrical path provided by the basal plane of each graphene layer. The high conductivity path can be employed for high frequency applications such as coupling coils for wireless power transmission to overcome skin depth effects and proximity effects prevalent in high frequency alternating current paths.

  15. Immunogenicity of coiled-coil based drug-free macromolecular therapeutics

    Czech Academy of Sciences Publication Activity Database

    Kverka, Miloslav; Hartley, J.M.; Chu, T.W.; Yang, J.; Heidchen, R.; Kopeček, J.

    2014-01-01

    Roč. 35, č. 2 (2014), s. 5886-5896 ISSN 1616-0177 R&D Projects: GA MŠk(CZ) EE2.3.30.0003 Grant - others:NIH(US) GM095606 Institutional support: RVO:61388971 Keywords : coiled-coil * enantiomers * HPMA copolymer Subject RIV: EC - Immunology

  16. Golgi coiled-coil proteins contain multiple binding sites for Rab family G proteins

    NARCIS (Netherlands)

    Sinka, Rita; Gillingham, Alison K.; Kondylis, Vangelis; Munro, Sean

    2008-01-01

    Vesicles and other carriers destined for the Golgi apparatus must be guided to the correct cisternae. Golgins, long coiled-coil proteins that localize to particular Golgi subdomains via their C termini, are candidate regulators of vesicle sorting. In this study, we report that the GRIP domain

  17. Analysis and experimental study of wireless power transfer with HTS coil and copper coil as the intermediate resonators system

    International Nuclear Information System (INIS)

    Wang, Xiufang; Nie, Xinyi; Liang, Yilang; Lu, Falong; Yan, Zhongming; Wang, Yu

    2017-01-01

    Highlights: • We investigated a kind of system architecture with three coils which the repeater is copper coil or HTS coil. • We simulated the different repeater system and obtained the magnetic field distribution at different distance. • We used helical coil instead of pancake coil which does not use capacitors. • HTS intermediate coil has significant effect on improving the transmission efficiency and lengthening transmission distance than copper intermediate coil. - Abstract: Intermediate resonator (repeater) between transmitter and receiver can significantly increase the distance of wireless power transfer (WPT) and the efficiency of wireless power transfer. The wireless power transfer via strongly coupled magnetic resonances with an high temperature superconducting (HTS) coil and copper coil as intermediate resonators was presented in this paper. The electromagnetic experiment system under different conditions with different repeating coils were simulated by finite element software. The spatial distribution patterns of magnetic induction intensity at different distances were plotted. In this paper, we examined transfer characteristics with HTS repeating coil and copper repeating coil at 77 K and 300 K, respectively. Simulation and experimental results show that HTS and copper repeating coil can effectively enhance the space magnetic induction intensity, which has significant effect on improving the transmission efficiency and lengthening transmission distance. We found that the efficiency and the distance of wireless power transfer system with an HTS coil as repeater is much higher by using of copper coil as repeater.

  18. Analysis and experimental study of wireless power transfer with HTS coil and copper coil as the intermediate resonators system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiufang [School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Physics and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Nie, Xinyi [School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Liang, Yilang [School of Physics and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Lu, Falong [School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Yan, Zhongming, E-mail: wangxiufanghappy@163.com [School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Wang, Yu [School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2017-01-15

    Highlights: • We investigated a kind of system architecture with three coils which the repeater is copper coil or HTS coil. • We simulated the different repeater system and obtained the magnetic field distribution at different distance. • We used helical coil instead of pancake coil which does not use capacitors. • HTS intermediate coil has significant effect on improving the transmission efficiency and lengthening transmission distance than copper intermediate coil. - Abstract: Intermediate resonator (repeater) between transmitter and receiver can significantly increase the distance of wireless power transfer (WPT) and the efficiency of wireless power transfer. The wireless power transfer via strongly coupled magnetic resonances with an high temperature superconducting (HTS) coil and copper coil as intermediate resonators was presented in this paper. The electromagnetic experiment system under different conditions with different repeating coils were simulated by finite element software. The spatial distribution patterns of magnetic induction intensity at different distances were plotted. In this paper, we examined transfer characteristics with HTS repeating coil and copper repeating coil at 77 K and 300 K, respectively. Simulation and experimental results show that HTS and copper repeating coil can effectively enhance the space magnetic induction intensity, which has significant effect on improving the transmission efficiency and lengthening transmission distance. We found that the efficiency and the distance of wireless power transfer system with an HTS coil as repeater is much higher by using of copper coil as repeater.

  19. Automated de novo phasing and model building of coiled-coil proteins.

    Science.gov (United States)

    Rämisch, Sebastian; Lizatović, Robert; André, Ingemar

    2015-03-01

    Models generated by de novo structure prediction can be very useful starting points for molecular replacement for systems where suitable structural homologues cannot be readily identified. Protein-protein complexes and de novo-designed proteins are examples of systems that can be challenging to phase. In this study, the potential of de novo models of protein complexes for use as starting points for molecular replacement is investigated. The approach is demonstrated using homomeric coiled-coil proteins, which are excellent model systems for oligomeric systems. Despite the stereotypical fold of coiled coils, initial phase estimation can be difficult and many structures have to be solved with experimental phasing. A method was developed for automatic structure determination of homomeric coiled coils from X-ray diffraction data. In a benchmark set of 24 coiled coils, ranging from dimers to pentamers with resolutions down to 2.5 Å, 22 systems were automatically solved, 11 of which had previously been solved by experimental phasing. The generated models contained 71-103% of the residues present in the deposited structures, had the correct sequence and had free R values that deviated on average by 0.01 from those of the respective reference structures. The electron-density maps were of sufficient quality that only minor manual editing was necessary to produce final structures. The method, named CCsolve, combines methods for de novo structure prediction, initial phase estimation and automated model building into one pipeline. CCsolve is robust against errors in the initial models and can readily be modified to make use of alternative crystallographic software. The results demonstrate the feasibility of de novo phasing of protein-protein complexes, an approach that could also be employed for other small systems beyond coiled coils.

  20. Extrap with iron-cored coils

    International Nuclear Information System (INIS)

    Lehnert, B.

    1985-05-01

    In Extrap configurations there is a high average beta value with respect to the plasma confinement volume. The externally imposed magnetic field which is required for stabilization therefore comes out to have a rather moderate strength, even under expected reactor conditions. As a consequence, this field can be generated not only by conventional external conductor arrangements, but also by iron-cored coils being operated below the saturation limit. A proposal for such iron-cored coil systems is presented in this paper. As compared to conventional conductors, this has the advantage of localizing the magnetic energy of the externally imposed magnetic field mainly to the discharge vessel and the plasma volume, thereby increasing the engineering beta value substantially. Also the problems of the coil stresses and of irradiation of the coils appear to become simplified, as well as replacement of the coil system. A main limitation of this proposal is due to combination of iron core saturation with the required stabilization effect from an ion Larmor radius of sufficient relative magnitude. This limitaion requires further investigation, especially in the full-scale reactor case. Also the modifications of the field geometry by iron core shaping needs further analysis. (Author)

  1. Effects of insulation on potted superconducting coils

    International Nuclear Information System (INIS)

    Zeller, A.F.; DeKamp, J.C.; Magsig, C.T.; Nolen, J.A.; McInturff, A.D.

    1989-01-01

    Test coils using identical wire but with either Formvar or Polyesterimid insulation were fabricated to determine the effects of insulation on training behavior. It was found that the type of insulation did not affect the training behavior. While considerable attention has been paid to epoxy formulations used for superconducting coils, little study has been devoted to the effects of the wire insulation on training behavior. If the insulation does not bind well with the epoxy, the wires will not be held securely in place, and training will be required to make the coil operate at its design limit. In fact, the coil may never reach its design current, showing considerable degredation. Conversely, if the epoxy-insulation reaction is to soften or weaken the insulation, then shorts and/or training may result. The authors have undertaken a study of the effects of the insulation on potted coils wet wound with Stycast 2850 FT epoxy. The wire was insulated with one of two insulting varnishes: Formvar (a polyvinyl formal resin) or Polyesterimid (a phenolic resin). Formvar is the standard insulation in the United States while Polyesterimid the European standard

  2. The design of the SULTAN inner coil

    International Nuclear Information System (INIS)

    Franken, W.M.P.; Spoorenberg, C.J.G.

    1981-12-01

    The background field of the first phase of the test facility SULTAN will be generated by two concentric solenoids: a 6 Tesla outer coil with a free bore of 1.3 m and an inner coil for increasing the field to 8 Tesla. The free bore (cold) will be 1.055 m. The final design of the 8 Tesla inner coil is described. The coil will operate at an overall current density of 23 x 10 6 A/m 2 . It will be cooled directly by forced flow supercritical helium. A hollow conductor is applied, composed of a rectangular copper tube and a 16 strands Rutherford cable, soldered on one side of the tube. The copper tube will be cold worked to cope with the high stress level (165 MPa). The design base (field and stress analysis, cooling, stability), the mechanical design and the instrumentation will be specified. The design and construction of the coil is a part of the collaboration between ECN and Holec Transformer Group

  3. Kivistatud kurjad teod / Peeter Pere

    Index Scriptorium Estoniae

    Pere, Peeter, 1957-

    2011-01-01

    Kommunismiohvrite memoriaali ideekavandite võistlusest, võidutöödest. I-II preemia - märgusõna Vest (autorid Armin Valter, Joel Kopli). I-II preemia - märgusõna Mälutulbad (autor Koit Ojaliiv). Eripreemiad - märgusõna Otsuste rand (autorid Roland Reemaa, Laura Linsi), märgusõna Introvert (autorid Urmas Paul, Martin Lepplaan, Evelin Reimand, Martin Noorväli), märgusõna Padakonn (autorid Vadim Fomitsev, Mart Liho, Ekke Väli)

  4. Oma pere keskel / Shanti Broeng

    Index Scriptorium Estoniae

    Broeng, Shanti

    2005-01-01

    Taani disaineri Anja Blinkenbergi, tema mehe Kaspari ning 9-aastaste kaksikuist poegade Emili ja Alberti Kopenhaagenis asuva ridamajakorteri kaunistamisest jõuludeks. Jõulukaunistuste meisterdamisest, jõulukuuse ehtimisest, kingituste pakkimisest. 14 värv. ill

  5. Critical current studies of a HTS rectangular coil

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Z. [Department of Engineering, University of Cambridge (United Kingdom); Chudy, M., E-mail: Michal.chudy@stuba.sk [Graduate School of Technology Management, University of Pretoria (South Africa); Institute of Power and Applied Electrical Engineering, Slovak University of Technology in Bratislava (Slovakia); Ruiz, H.S. [Department of Engineering, University of Leicester, Leicester LE1 7RH (United Kingdom); Zhang, X.; Coombs, T. [Department of Engineering, University of Cambridge (United Kingdom)

    2017-05-15

    Highlights: • Unique square pancake coil was manufactured. • Measurements in relatively high magnetic field were performed. • Different sections of the coil were characterized. • Parts of the coil which are limiting critical current were identified. - Abstract: Nowadays, superconducting high field magnets are used in numerous applications due to their superior properties. High temperature superconductors (HTS) are usually used for production of circular pancake or racetrack coils. However different geometries of HTS coils might be required for some specific applications. In this study, the HTS coil wound on a rectangular frame was fully characterized in homogeneous DC background field. The study contains measurements of critical current angular dependencies. The critical current of the entire coil and two selected strands under different magnitudes and orientations of external magnetic fields are measured. The critical regions of the coil in different angular regimes are determined. This study brings better understanding of the in- field performance of HTS coils wound on frames with right-angles.

  6. Wireless induction coils embedded in diamond for power transfer in medical implants.

    Science.gov (United States)

    Sikder, Md Kabir Uddin; Fallon, James; Shivdasani, Mohit N; Ganesan, Kumaravelu; Seligman, Peter; Garrett, David J

    2017-08-26

    Wireless power and data transfer to medical implants is a research area where improvements in current state-of-the-art technologies are needed owing to the continuing efforts for miniaturization. At present, lithographical patterning of evaporated metals is widely used for miniature coil fabrication. This method produces coils that are limited to low micron or nanometer thicknesses leading to high impedance values and thus limiting their potential quality. In the present work we describe a novel technique, whereby trenches were milled into a diamond substrate and filled with silver active braze alloy, enabling the manufacture of small, high cross-section, low impedance microcoils capable of transferring up to 10 mW of power up to a distance of 6 mm. As a substitute for a metallic braze line used for hermetic sealing, a continuous metal loop when placed parallel and close to the coil surface reduced power transfer efficiency by 43%, but not significantly, when placed perpendicular to the microcoil surface. Encapsulation of the coil by growth of a further layer of diamond reduced the quality factor by an average of 38%, which can be largely avoided by prior oxygen plasma treatment. Furthermore, an accelerated ageing test after encapsulation showed that these coils are long lasting. Our results thus collectively highlight the feasibility of fabricating a high-cross section, biocompatible and long lasting miniaturized microcoil that could be used in either a neural recording or neuromuscular stimulation device.

  7. Feasibility studies on plasma vertical position control by ex-vessel coils in ITER-like tokamak fusion reactors

    International Nuclear Information System (INIS)

    Nishio, Satoshi; Sugihara, Masayoshi; Shimomura, Yasuo

    1993-01-01

    Feasibility of the plasma vertical position control by control coils installed outside the vacuum vessel (ex-vessel) in a tokamak fusion reactor is examined for an ITER-like device. When a pair of ex-vessel control coils is made of normal conductor material and located near the outmost superconducting (SC) poloidal field (PF) coils, the applied voltage of several hundred volts on the control coils is the maximum allowable value which is limited by the maximum allowable induced voltage and eddy current heating on the SC PF coils, under the conditions that the SC PF coils are connected in series and a partitioning connection is employed for each of these PF coils. A proportional and derivative (PD) controller with and without voltage limitation has been employed to examine the feasibility. Indices of settling time and overshoot are introduced to measure the controllability of the control system. Based on these control schemes and indices, higher elongation (κ=2) and moderate elongation (κ=1.6) plasmas are examined for normal and deteriorated (low beta value and peaked current profile) plasma conditions within the restriction of applied voltage and current of control coils. The effect of the time constant of the passive stabilizer is also examined. The major results are: (1) A plasma with an elongation of 2.0 inevitably requires a passive stabilizer close to the plasma surface, (2) in case of a higher elongation than κ=2, even the ex-vessel control coil system is marginally controllable under normal plasma conditions, while it is difficult to control the deteriorated plasma conditions, (3) the time constant of the passive stabilizer is not an essential parameter for the controllability, (4) when the elongation is reduced down to 1.6, the ex-vessel control coil system can control the plasma even under deteriorated plasma conditions. (orig.)

  8. CS model coil experimental log book

    Energy Technology Data Exchange (ETDEWEB)

    Nishijima, Gen; Sugimoto, Makoto; Nunoya, Yoshihiko; Wakabayashi, Hiroshi; Tsuji, Hiroshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-02-01

    Charging test of the ITER CS Model Coil which is the world's largest superconducting pulse coil and the CS Insert Coil had started at April 11, 2000 and had completed at August 18, 2000. In the campaign, total shot numbers were 356 and the size of the data file in the DAS (Data Acquisition System) was over 20 GB. This report is a database that consists of the log list and the log sheets of every shot. One can access the database, make a search, and browse results via Internet (http://1ogwww.naka.jaeri.go.jp). The database will be useful to quick search to choose necessary shots. (author)

  9. OCLATOR (One Coil Low Aspect Toroidal Reactor)

    International Nuclear Information System (INIS)

    Yoshikawa, S.

    1980-02-01

    A new approach to construct a tokamak-type reactor(s) is presented. Basically the return conductors of toroidal field coils are eliminated and the toroidal field coil is replaced by one single large coil, around which there will be placed several tokamaks or other toroidal devices. The elimination of return conductors should, in addition to other advantages, improve the accessibility and maintainability of the tokamaks and offer a possible alternative to the search for special materials to withstand large neutron wall loading, as the frequency of changeover would be increased due to minimum downtime. It also makes it possible to have a low aspect ratio tokamak which should improve the β limit, so that a low toroidal magnetic field strength might be acceptable, meaning that the NbTi superconducting wire could be used. This system is named OCLATOR

  10. MFTF test coil construction and performance

    International Nuclear Information System (INIS)

    Cornish, D.N.; Zbasnik, J.P.; Leber, R.L.; Hirzel, D.G.; Johnston, J.E.; Rosdahl, A.R.

    1978-01-01

    A solenoid coil, 105 cm inside the 167 cm outside diameter, has been constructed and tested to study the performance of the stabilized Nb--Ti conductor to be used in the Mirror Fusion Test Facility (MFTF) being built at Lawrence Livermore Laboratory. The insulation system of the test coil is identical to that envisioned for MFTF. Cold-weld joints were made in the conductor at the start and finish of each layer; heaters were fitted to some of these joints and also to the conductor at various locations in the winding. This paper gives details of the construction of the coil and the results of the tests carried out to determine its propagation and recovery characteristics

  11. Considerations against a force compensated coil

    International Nuclear Information System (INIS)

    Hassenzahl, W.

    1988-08-01

    The cost of structural components in a large superconducting coil may well exceed the coil and cryostat cost. As a result, the idea of constructing a system composed of two different coil types assembled in such a way that the sources balance and reduce the total structural requirement is oft proposed. A suitable geometry has never been found for the fundamental reason that there can be no force compensated solution. In this paper, the general problem is presented and an analysis of the energy stored and stresses produced in the structure are described in a fundamental way. Finally, the relation between structural mass M and stored energy E, M ≥/rho/E/σ/sub w/, that is valid for all magnetic systems is developed, where /rho/ is the density of the structure and σ/sub w/ is the working stress in the structure. 12 refs., 2 figs

  12. Considerations against a force compensated coil

    International Nuclear Information System (INIS)

    Hassenzahl, W.

    1988-08-01

    The cost of structural components in a large superconducting coil may well exceed the coil and cryostat cost. As a result, the idea of constructing a system composed of two different coil types assembled in such a way that the forces balance and reduce the total structural requirement is oft proposed. A suitable geometry has never been found for the fundamental reason that there can be no force compensated solution. In this paper, the general problem is presented and an analysis of the energy stored and stresses produced in the structure are described in a fundamental way. Finally, the relation between structural mass M and stored energy E, M ≥ /rho/E/σ/sub w/, that is valid for all magnetic systems is developed, where /rho/ is the density of the structure and σ/sub w/ is the working stress in the structure. 8 refs., 2 figs

  13. Acoustic rainbow trapping by coiling up space

    KAUST Repository

    Ni, Xu

    2014-11-13

    We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

  14. Isabelle dipole and quadrupole coil configurations

    International Nuclear Information System (INIS)

    Dahl, P.F.; Hahn, H.

    1980-01-01

    The coil configurations of the ISABELLE dipole and quadrupole magnets have been reviewed and a number of improvements were suggested for incorporation into the final design. The coil designs are basically single layer multiple block approximations to cosine current distributions, wound from a high aspect ratio non-keystoned braided conductor. The blocks are separated by knife-edge wedges to maximize the quench propagation velocity. The current density variation is obtained by an appropriate distribution of the spacer turns and, to a lesser degree, by the wedge locations. The use of inert turns is necessary to minimize the peak field enhancement both in the ends and in the two dimensional section. Schemes for deriving turns distributions yielding harmonic coefficients satisfying the stringent ISABELLE tolerances on field uniformity, while allowing for simplicity in winding and taking into account quench propagation considerations, will be discussed, as well as our approach to the coil end configuration

  15. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1985-01-01

    Several features of the problem of FRC translation into a compression coil are considered. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an ''abrupt transition'' model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  16. Acoustic rainbow trapping by coiling up space

    KAUST Repository

    Ni, Xu; Wu, Ying; Chen, Ze-Guo; Zheng, Li-Yang; Xu, Ye-Long; Nayar, Priyanka; Liu, Xiao-Ping; Lu, Ming-Hui; Chen, Yan-Feng

    2014-01-01

    We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

  17. High voltage investigations for ITER coils

    International Nuclear Information System (INIS)

    Fink, S.; Fietz, W.H.

    2006-01-01

    The superconducting ITER magnets will be excited with high voltage during operation and fast discharge. Because the coils are complex systems the internal voltage distribution can differ to a large extent from the ideal linear voltage distribution. In case of fast excitations internal voltages between conductor and radial plate of a TF coil can be even higher than the terminal voltage of 3.5 kV to ground which appears during a fast discharge without a fault. Hence the determination of the transient voltage distribution is important for a proper insulation co-ordination and will provide a necessary basis for the verification of the individual insulation design and the choice of test voltages and waveforms. Especially the extent of internal overvoltages in case of failures, e. g. malfunction of discharge units and / or arcing is of special interest. Transient calculations for the ITER TF coil system have been performed for fast discharge and fault scenarios to define test voltages for ITER TF. The conductor and radial plate insulation of the ITER TF Model Coil were exposed at room temperature to test voltages derived from the results from these calculations. Breakdown appeared during the highest AC voltage step. A fault scenario for the TF fast discharge system is presented where one fault triggers a second fault, leading to considerable voltage stress. In addition a FEM model of Poloidal Field Coil 3 for the determination of the parameters of a detailed network model is presented in order to prepare detailed investigations of the transient voltage behaviour of the PF coils. (author)

  18. Study of electric phenomena in energy dumping of LCT coil

    International Nuclear Information System (INIS)

    Oka, Koichi; Tsuji, Hiroshi; Nishi, Masataka; Shimamoto, Susumu

    1980-03-01

    In IEA-LCT coil, electric phenomena in energy dumping were studied analytically and experimentally. Protection resistance of the Japanese LCT coil is chosen as 0.1 Ω considering the quenching voltage, so that temperature rise of the coil is no problem. Energy dumping characteristic of the six-coil system is calculated under different conditions. It is concluded that simultaneous dumping of all the coils with the equivalent resistance values of protection is necessary. Flashover voltage tests of the model in 4.2 K liquid helium, 4.2 K gas helium and 4.2 K boiling helium show margin in practical quenching voltage of the coil. (author)

  19. Resistive demountable toroidal-field coils for tokamak reactors

    International Nuclear Information System (INIS)

    Jassby, D.L.; Jacobsen, R.A.; Kalnavarns, J.; Masson, L.S.; Sekot, J.P.

    1981-07-01

    Readily demountable TF (toroidal-field) coils allow complete access to the internal components of a tokamak reactor for maintenance of replacement. The requirement of readily demountable joints dictates the use of water-cooled resistive coils, which have a host of decisive advantages over superconducting coils. Previous papers have shown that resistive TF coils for tokamak reactors can operate in the steady state with acceptable power dissipation (typically, 175 to 300 MW). This paper summarizes results of parametric studies of size optimization of rectangular TF coils and of a finite-element stress analysis, and examines several candidate methods of implementing demountable joints for rectangular coils constructed of plate segments

  20. Stress distributions of coils for toroidal magnetic field

    International Nuclear Information System (INIS)

    Kajita, Tateo; Miyamoto, Kenro.

    1976-01-01

    The stress distributions of a D shaped coil and a circular coil are computed by the finite element method. The dependences of the stress distribution on the geometrical parameters of the stress distribution on the geometrical parameters of the coils and supporting methods are examined. The maximum amount of the stress in the D shaped coil is not much smaller than that of the circular one. However, the stress distribution of the D shaped coil becomes much more uniform. The supporting method has as much effect as the geometrical parameters of the coil on the stress distribution. (auth.)

  1. ADVANTAGES OF RAPID METHOD FOR DETERMINING SCALE MASS AND DECARBURIZED LAYER OF ROLLED COIL STEEL

    Directory of Open Access Journals (Sweden)

    E. V. Parusov

    2016-08-01

    Full Text Available Purpose. To determine the universal empirical relationships that allow for operational calculation of scale mass and decarbonized layer depth based on the parameters of the technological process for rolled coil steel production. Methodology. The research is carried out on the industrial batches of the rolled steel of SAE 1006 and SAE 1065 grades. Scale removability was determined in accordance with the procedure of «Bekaert» company by the specifi-cations: GA-03-16, GA-03-18, GS-03-02, GS-06-01. The depth of decarbonized layer was identified in accordance with GOST 1763-68 (M method. Findings. Analysis of experimental data allowed us to determine the rational temperature of coil formation of the investigated steel grades, which provide the best possible removal of scale from the metal surface, a minimal amount of scale, as well as compliance of the metal surface color with the require-ments of European consumers. Originality. The work allowed establishing correlation of the basic quality indicators of the rolled coil high carbon steel (scale mass, depth of decarbonized layer and inter-laminar distance in pearlite with one of the main parameters (coil formation temperature of the deformation and heat treatment mode. The re-sulting regression equations, without metallographic analysis, can be used to determine, with a minimum error, the quantitative values of the total scale mass, depth of decarbonized layer and the average inter-lamellar distance in pearlite of the rolled coil high carbon steel. Practical value. Based on the specifications of «Bekaert» company (GA-03-16, GA-03-18, GS-03-02 and GS-06-01 the method of testing descaling by mechanical means from the surface of the rolled coil steel of low- and high-carbon steel grades was developed and approved in the environment of PJSC «ArcelorMittal Kryvyi Rih». The work resulted in development of the rapid method for determination of total and remaining scale mass on the rolled coil steel

  2. Cooling a solar telescope enclosure: plate coil thermal analysis

    Science.gov (United States)

    Gorman, Michael; Galapon, Chriselle; Montijo, Guillermo; Phelps, LeEllen; Murga, Gaizka

    2016-08-01

    The climate of Haleakalā requires the observatories to actively adapt to changing conditions in order to produce the best possible images. Observatories need to be maintained at a temperature closely matching ambient or the images become blurred and unusable. The Daniel K. Inouye Solar Telescope is a unique telescope as it will be active during the day as opposed to the other night-time stellar observatories. This means that it will not only need to constantly match the ever-changing temperature during the day, but also during the night so as not to sub-cool and affect the view field of other telescopes while they are in use. To accomplish this task, plate coil heat exchanger panels will be installed on the DKIST enclosure that are designed to keep the temperature at ambient temperature +0°C/-4°C. To verify the feasibility of this and to validate the design models, a test rig has been installed at the summit of Haleakalā. The project's purpose is to confirm that the plate coil panels are capable of maintaining this temperature throughout all seasons and involved collecting data sets of various variables including pressures, temperatures, coolant flows, solar radiations and wind velocities during typical operating hours. Using MATLAB, a script was written to observe the plate coil's thermal performance. The plate coil did not perform as expected, achieving a surface temperature that was generally 2ºC above ambient temperature. This isn't to say that the plate coil does not work, but the small chiller used for the experiment was undersized resulting in coolant pumped through the plate coil that was not supplied at a low enough temperature. Calculated heat depositions were about 23% lower than that used as the basis of the design for the hillers to be used on the full system, a reasonable agreement given the fact that many simplifying assumptions were used in the models. These were not carried over into the testing. The test rig performance showing a 23% margin

  3. Zero current measurements using the Rogowski coil

    International Nuclear Information System (INIS)

    Gregor, J.; Jakubova, I.; Kadlec, P.; Senk, J.; Vavra, Z.

    1997-01-01

    The zero current measurements using the Rogowski coil carried out on the model of the extinguishing chamber of hv SF 6 circuit breaker with self-flow generation are presented in the paper. The time course of the post-arc current obtained by numerical integration of the measured induced voltage of the Rogowski coil gives information not only about the value of the residual current after the successful interruption but also about the current changes connected with the dynamic behaviour of the arc during its quenching. (author)

  4. Self-assembling segmented coiled tubing

    Science.gov (United States)

    Raymond, David W.

    2016-09-27

    Self-assembling segmented coiled tubing is a concept that allows the strength of thick-wall rigid pipe, and the flexibility of thin-wall tubing, to be realized in a single design. The primary use is for a drillstring tubular, but it has potential for other applications requiring transmission of mechanical loads (forces and torques) through an initially coiled tubular. The concept uses a spring-loaded spherical `ball-and-socket` type joint to interconnect two or more short, rigid segments of pipe. Use of an optional snap ring allows the joint to be permanently made, in a `self-assembling` manner.

  5. Multiple coil closure of isolated aortopulmonary collateral

    Directory of Open Access Journals (Sweden)

    Padhi Sumanta

    2010-01-01

    Full Text Available A 7-month-old girl was diagnosed to have large aortopulmonary collateral during evaluation for congestive heart failure. There was no other evidence of cardiopulmonary disease. The collateral was successfully closed with multiple coils delivered sequentially. We describe the issues associated during closure of the aortopulmonary collateral in this case. To the best of our knowledge, this is the first reported case of large aortopulmonary collateral presenting with heart failure in an otherwise structurally normal heart that was closed successfully with multiple coils delivered sequentially.

  6. Superconducting Coil Winding Machine Control System

    Energy Technology Data Exchange (ETDEWEB)

    Nogiec, J. M. [Fermilab; Kotelnikov, S. [Fermilab; Makulski, A. [Fermilab; Walbridge, D. [Fermilab; Trombly-Freytag, K. [Fermilab

    2016-10-05

    The Spirex coil winding machine is used at Fermilab to build coils for superconducting magnets. Recently this ma-chine was equipped with a new control system, which al-lows operation from both a computer and a portable remote control unit. This control system is distributed between three layers, implemented on a PC, real-time target, and FPGA, providing respectively HMI, operational logic and direct controls. The system controls motion of all mechan-ical components and regulates the cable tension. Safety is ensured by a failsafe, redundant system.

  7. A new type of coil structure called pan-shaped coil of wireless charging system based on magnetic resonance

    Science.gov (United States)

    Yue, Z. K.; Liu, Z. Z.; Hou, Y. J.; Zeng, H.; Liang, L. H.; Cui, S.

    2017-11-01

    The problem that misalignment between the transmitting coil and the receiving coil significantly impairs the transmission power and efficiency of the system has been attached more and more attention. In order to improve the uniformity of the magnetic field between the two coils to solve this problem, a new type of coil called pan-shaped coil is proposed. Three-dimension simulation models of the planar-core coil and the pan-shaped coil are established using Ansoft Maxwell software. The coupling coefficient between the transmitting coil and the receiving coil is obtained by simulating the magnetic field with the receiving coil misalignment or not. And the maximum percentage difference strength along the radial direction which is defined as the magnetic field uniformity factor is calculated. According to the simulation results of the two kinds of coil structures, it is found that the new type of coil structure can obviously improve the uniformity of the magnetic field, coupling coefficient and power transmission properties between the transmitting coil and the receiving coil.

  8. Fine-tuning of protein domain boundary by minimizing potential coiled coil regions

    International Nuclear Information System (INIS)

    Iwaya, Naoko; Goda, Natsuko; Unzai, Satoru; Fujiwara, Kenichiro; Tanaka, Toshiki; Tomii, Kentaro; Tochio, Hidehito; Shirakawa, Masahiro; Hiroaki, Hidekazu

    2007-01-01

    Structural determination of individual protein domains isolated from multidomain proteins is a common approach in the post-genomic era. Novel and thus uncharacterized domains liberated from intact proteins often self-associate due to incorrectly defined domain boundaries. Self-association results in missing signals, poor signal dispersion and a low signal-to-noise ratio in 1 H- 15 N HSQC spectra. We have found that a putative, non-canonical coiled coil region close to a domain boundary can cause transient hydrophobic self-association and monomer-dimer equilibrium in solution. Here we propose a rational method to predict putative coiled coil regions adjacent to the globular core domain using the program COILS. Except for the amino acid sequence, no preexisting knowledge concerning the domain is required. A small number of mutant proteins with a minimized coiled coil region have been rationally designed and tested. The engineered domains exhibit decreased self-association as assessed by 1 H- 15 N HSQC spectra with improved peak dispersion and sharper cross peaks. Two successful examples of isolating novel N-terminal domains from AAA-ATPases are demonstrated. Our method is useful for the experimental determination of domain boundaries suited for structural genomics studies

  9. Fine-tuning of protein domain boundary by minimizing potential coiled coil regions.

    Science.gov (United States)

    Iwaya, Naoko; Goda, Natsuko; Unzai, Satoru; Fujiwara, Kenichiro; Tanaka, Toshiki; Tomii, Kentaro; Tochio, Hidehito; Shirakawa, Masahiro; Hiroaki, Hidekazu

    2007-01-01

    Structural determination of individual protein domains isolated from multidomain proteins is a common approach in the post-genomic era. Novel and thus uncharacterized domains liberated from intact proteins often self-associate due to incorrectly defined domain boundaries. Self-association results in missing signals, poor signal dispersion and a low signal-to-noise ratio in (1)H-(15)N HSQC spectra. We have found that a putative, non-canonical coiled coil region close to a domain boundary can cause transient hydrophobic self-association and monomer-dimer equilibrium in solution. Here we propose a rational method to predict putative coiled coil regions adjacent to the globular core domain using the program COILS. Except for the amino acid sequence, no preexisting knowledge concerning the domain is required. A small number of mutant proteins with a minimized coiled coil region have been rationally designed and tested. The engineered domains exhibit decreased self-association as assessed by (1)H-(15)N HSQC spectra with improved peak dispersion and sharper cross peaks. Two successful examples of isolating novel N-terminal domains from AAA-ATPases are demonstrated. Our method is useful for the experimental determination of domain boundaries suited for structural genomics studies.

  10. Results of measurements with a superconducting niobium coil resonator at 106 MHz: the story of a coil

    International Nuclear Information System (INIS)

    Piosczyk, B.

    A number of tests were performed with a newly developed coil. The surface was treated by conventional surface treatment methods. In the first tests, breakdown occurred at field strengths E/sub max/ approximately equal to 11 to 14 MV/m. The reason for the early breakdown was presumed to reside in small sites with increased losses which expand above a critical field strength. Only after a series of treatment steps in which a total of about 160 μ had been removed from the coil surface were maximum surface fields of up to E/sub max/ approximately equal to 29 MV/m and B/sub max/ approximately equal to 1050 Oe (greater than or equal to E/sub TW/ approximately equal to 4.0 MV/m) reached. Subsequently, breakdown is usually caused by electrons. A comparison of anodized and unanodized resonators showed no significant difference for the maximum attainable field strengths or in the characteristics with regard to electron loading and sensitivity to gas contamination. In two long-term tests for up to 800 h, the resonator was operated at high HF-field strengths (E/sub max/ approximately equal to 18 to 24 MV/m). An abrupt increase of e-loading, which was connected with increased resonator losses, was observed at certain time intervals. Subsequent He-conditioning for a few minutes reduced this elevated e-loading. With increasing operating time, an increase of surface losses was observed which were evidently caused by electrons impinging on the surface (radiation damage). The magnitude of the radiation damage appears to be rather uncritical for application. This radiation damage does not heal during heating to room temperature. However, light oxidative polishing suffices to eliminate the radiation damage

  11. Four signature motifs define the first class of structurally related large coiled-coil proteins in plants.

    Directory of Open Access Journals (Sweden)

    Meier Iris

    2002-04-01

    Full Text Available Abstract Background Animal and yeast proteins containing long coiled-coil domains are involved in attaching other proteins to the large, solid-state components of the cell. One subgroup of long coiled-coil proteins are the nuclear lamins, which are involved in attaching chromatin to the nuclear envelope and have recently been implicated in inherited human diseases. In contrast to other eukaryotes, long coiled-coil proteins have been barely investigated in plants. Results We have searched the completed Arabidopsis genome and have identified a family of structurally related long coiled-coil proteins. Filament-like plant proteins (FPP were identified by sequence similarity to a tomato cDNA that encodes a coiled-coil protein which interacts with the nuclear envelope-associated protein, MAF1. The FPP family is defined by four novel unique sequence motifs and by two clusters of long coiled-coil domains separated by a non-coiled-coil linker. All family members are expressed in a variety of Arabidopsis tissues. A homolog sharing the structural features was identified in the monocot rice, indicating conservation among angiosperms. Conclusion Except for myosins, this is the first characterization of a family of long coiled-coil proteins in plants. The tomato homolog of the FPP family binds in a yeast two-hybrid assay to a nuclear envelope-associated protein. This might suggest that FPP family members function in nuclear envelope biology. Because the full Arabidopsis genome does not appear to contain genes for lamins, it is of interest to investigate other long coiled-coil proteins, which might functionally replace lamins in the plant kingdom.

  12. Three-dimensional proton MR spectroscopy of human prostate at 3 T without endorectal coil: feasibility.

    NARCIS (Netherlands)

    Scheenen, T.W.J.; Heijmink, S.W.T.P.J.; Roell, S.A.; Hulsbergen-van de Kaa, C.A.; Knipscheer, B.C.; Witjes, J.A.; Barentsz, J.O.; Heerschap, A.

    2007-01-01

    PURPOSE: To evaluate sensitivity and specificity of proton magnetic resonance (MR) spectroscopy of the prostate with external surface coil elements at 3 T for differentiation of cancer from healthy tissue within an acceptable measurement time, by using histopathologic findings as the reference

  13. Characteristics of bowl-shaped coils for transcranial magnetic stimulation

    Science.gov (United States)

    Yamamoto, Keita; Suyama, Momoko; Takiyama, Yoshihiro; Kim, Dongmin; Saitoh, Youichi; Sekino, Masaki

    2015-05-01

    Transcranial magnetic stimulation (TMS) has recently been used as a method for the treatment of neurological and psychiatric diseases. Daily TMS sessions can provide continuous therapeutic effectiveness, and the installation of TMS systems at patients' homes has been proposed. A figure-eight coil, which is normally used for TMS therapy, induces a highly localized electric field; however, it is challenging to achieve accurate coil positioning above the targeted brain area using this coil. In this paper, a bowl-shaped coil for stimulating a localized but wider area of the brain is proposed. The coil's electromagnetic characteristics were analyzed using finite element methods, and the analysis showed that the bowl-shaped coil induced electric fields in a wider area of the brain model than a figure-eight coil. The expanded distribution of the electric field led to greater robustness of the coil to the coil-positioning error. To improve the efficiency of the coil, the relationship between individual coil design parameters and the resulting coil characteristics was numerically analyzed. It was concluded that lengthening the outer spherical radius and narrowing the width of the coil were effective methods for obtaining a more effective and more uniform distribution of the electric field.

  14. Numerical simulations on active shielding methods comparison and wrapped angle optimization for gradient coil design in MRI with enhanced shielding effect

    Science.gov (United States)

    Wang, Yaohui; Xin, Xuegang; Guo, Lei; Chen, Zhifeng; Liu, Feng

    2018-05-01

    The switching of a gradient coil current in magnetic resonance imaging will induce an eddy current in the surrounding conducting structures while the secondary magnetic field produced by the eddy current is harmful for the imaging. To minimize the eddy current effects, the stray field shielding in the gradient coil design is usually realized by minimizing the magnetic fields on the cryostat surface or the secondary magnetic fields over the imaging region. In this work, we explicitly compared these two active shielding design methods. Both the stray field and eddy current on the cryostat inner surface were quantitatively discussed by setting the stray field constraint with an ultra-low maximum intensity of 2 G and setting the secondary field constraint with an extreme small shielding ratio of 0.000 001. The investigation revealed that the secondary magnetic field control strategy can produce coils with a better performance. However, the former (minimizing the magnetic fields) is preferable when designing a gradient coil with an ultra-low eddy current that can also strictly control the stray field leakage at the edge of the cryostat inner surface. A wrapped-edge gradient coil design scheme was then optimized for a more effective control of the stray fields. The numerical simulation on the wrapped-edge coil design shows that the optimized wrapping angles for the x and z coils in terms of our coil dimensions are 40° and 90°, respectively.

  15. Impact of the use of an endorectal coil for 3 T prostate MRI on image quality and cancer detection rate.

    Science.gov (United States)

    Gawlitza, Josephin; Reiss-Zimmermann, Martin; Thörmer, Gregor; Schaudinn, Alexander; Linder, Nicolas; Garnov, Nikita; Horn, Lars-Christian; Minh, Do Hoang; Ganzer, Roman; Stolzenburg, Jens-Uwe; Kahn, Thomas; Moche, Michael; Busse, Harald

    2017-02-01

    This work aims to assess the impact of an additional endorectal coil on image quality and cancer detection rate within the same patients. At a single academic medical center, this transversal study included 41 men who underwent T2- and diffusion-weighted imaging at 3 T using surface coils only or in combination with an endorectal coil in the same session. Two blinded readers (A and B) randomly evaluated all image data in separate sessions. Image quality with respect to localization and staging was rated on a five-point scale. Lesions were classified according to their prostate imaging reporting and data system (PIRADS) score version 1. Standard of reference was provided by whole-mount step-section analysis. Mean image quality scores averaged over all localization-related items were significantly higher with additional endorectal coil for both readers (p < 0.001), corresponding staging-related items were only higher for reader B (p < 0.001). With an endorectal coil, the rate of correctly detecting cancer per patient was significantly higher for reader B (p < 0.001) but not for reader A (p = 0.219). The numbers of histologically confirmed tumor lesions were rather similar for both settings. The subjectively rated 3-T image quality was improved with an endorectal coil. In terms of diagnostic performance, the use of an additional endorectal coil was not superior.

  16. TEXT poloidal coil systems power supplies

    International Nuclear Information System (INIS)

    Hutchins, S.H.; Brower, D.F.

    1977-01-01

    TEXT is a convertional iron core tokamak which will have a toroidal field of 3.0 Tesla produced by room temperature copper coils and a maximum plasma current pulse of 400 kA induced by a 40 turn Ohmic Heating coil. The major radius is 100 cm and the minor radius of the plasma is 28 cm. The machine is intended for basic research in tokamak plasma physics and atomic physics and is designed primarily to provide a stable hot plasma, extremely good diagnostic access, and reliable operation. The discharge pulse length will be 300 msec and the repetition period 120 seconds. Power for the toroidal field coils and for the ohmic heating supply is provided by a 100 MVA energy storage alternator. The vertical field, horizontal field, fast positioning, and discharge cleaning power supply systems are powered from the Tokamak Laboratory power mains. The ohmic heating power system consists of an SCR controlled premagnetizing supply and commutation circuit, the main ohmic heating capacitor bank to provide plasma breakdown and current rise, and an SCR controlled power supply which sustains plasma current during the 300 ms pulse. The vertical field power system uses a small capacitor bank and an SCR controlled supply. The horizontal field has a reversible SCR controlled supply, and the fast positioning coils are powered by bipolar output transistor controlled supplies. This paper describes the loads, required wave forms, and the specifications for these power supply systems

  17. Coiling of ruptured pericallosal artery aneurysms.

    NARCIS (Netherlands)

    Menovsky, T.; Rooij, W.J.J. van; Sluzewski, M.; Wijnalda, D.

    2002-01-01

    OBJECTIVE: To assess the technical feasibility of treating ruptured pericallosal artery aneurysms with detachable coils and to evaluate the anatomic and clinical results. METHODS: Over a period of 27 months, 12 patients with a ruptured pericallosal artery aneurysm were treated with detachable

  18. Transcatheter Coil Embolization of Splenic Artery Aneurysm

    International Nuclear Information System (INIS)

    Yamamoto, Satoshi; Hirota, Shozo; Maeda, Hiroaki; Achiwa, Sachiko; Arai, Keisuke; Kobayashi, Kaoru; Nakao, Norio

    2008-01-01

    The purpose of this study was to evaluate clinical results and technical problems of transcatheter coil embolization for splenic artery aneurysm. Subjects were 16 patients (8 men, 8 women; age range, 40-80 years) who underwent transcatheter embolization for splenic artery aneurysm (14 true aneurysms, 2 false aneurysms) at one of our hospitals during the period January 1997 through July 2005. Two aneurysms (12.5%) were diagnosed at the time of rupture. Multiple splenic aneurysms were found in seven patients. Aneurysms were classified by site as proximal (or strictly ostial) (n = 3), middle (n = 3), or hilar (n = 10). The indication for transcatheter arterial embolization was a false or true aneurysm 20 mm in diameter. Embolic materials were fibered coils and interlocking detachable coils. Embolization was performed by the isolation technique, the packing technique, or both. Technically, all aneurysms were devascularized without severe complications. Embolized aneurysms were 6-40 mm in diameter (mean, 25 mm). Overall, the primary technical success rate was 88% (14 of 16 patients). In the remaining 2 patients (12.5%), partial recanalization occurred, and re-embolization was performed. The secondary technical success rate was 100%. Seven (44%) of the 16 study patients suffered partial splenic infarction. Intrasplenic branching originating from the aneurysm was observed in five patients. We conclude that transcatheter coil embolization should be the initial treatment of choice for splenic artery aneurysm

  19. Stellarator Coil Design and Plasma Sensitivity

    International Nuclear Information System (INIS)

    Ku, Long-Poe; Boozer, Allen H.

    2010-01-01

    The rich information contained in the plasma response to external magnetic perturbations can be used to help design stellarator coils more effectively. We demonstrate the feasibility by first devel oping a simple, direct method to study perturbations in stellarators that do not break stellarator symmetry and periodicity. The method applies a small perturbation to the plasma boundary and evaluates the resulting perturbed free-boundary equilibrium to build up a sensitivity matrix for the important physics attributes of the underlying configuration. Using this sensitivity information, design methods for better stellarator coils are then developed. The procedure and a proof-of-principle application are given that (1) determine the spatial distributions of external normal magnetic field at the location of the unperturbed plasma boundary to which the plasma properties are most sen- sitive, (2) determine the distributions of external normal magnetic field that can be produced most efficiently by distant coils, (3) choose the ratios of the magnitudes of the the efficiently produced magnetic distributions so the sensitive plasma properties can be controlled. Using these methods, sets of modular coils are found for the National Compact Stellarator Experiment (NCSX) that are either smoother or can be located much farther from the plasma boundary than those of the present design.

  20. High-field superconducting nested coil magnet

    Science.gov (United States)

    Laverick, C.; Lobell, G. M.

    1970-01-01

    Superconducting magnet, employed in conjunction with five types of superconducting cables in a nested solenoid configuration, produces total, central magnetic field strengths approaching 70 kG. The multiple coils permit maximum information on cable characteristics to be gathered from one test.

  1. Coil in bottom part of splitter magnet

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    Radiation-resistant coil being bedded into the bottom part of a splitter magnet. This very particular magnet split the beam into 3 branches, for 3 target stations in the West-Area. See Annual Report 1975, p.176, Figs.14 and 15.

  2. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1986-01-01

    The equilibrium and translational kinematics of Field-Reversed Configurations (FRCs) in a cylindrical coil which does not conserve flux are problems that arise in connection with adiabatic compressional heating. In this paper, they consider several features of the problem of FRC translation into a compression coil. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an abrupt transition model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  3. Traveling-wave synchronous coil gun

    International Nuclear Information System (INIS)

    Elliott, D.G.

    1991-01-01

    This paper reports on a traveling-wave synchronous coil gun which permits independent adjustment of the magnetic field and armature current for high velocity at low armature mass fraction. Magnetic field energy is transferred from the rear of the wave to the front without passing through the power supply. Elaborate switching is required

  4. Structural design of the superconducting toroidal field coils for ITER

    International Nuclear Information System (INIS)

    Wong, F.M.G.; Sborchia, C.; Thome, R.J.; Malkov, A.; Titus, P.H.

    1995-01-01

    Structural design issues and features of the superconducting toroidal field (TF) coils for the International Thermonuclear Experimental Reactor (ITER) will be discussed. Selected analyses of the structural and mechanical behavior of the ITER TF coils will also be presented. (orig.)

  5. Hybrid equilibrium field coils for the ORNL TNS

    International Nuclear Information System (INIS)

    Peng, Y.K.M.; Strickler, D.J; Dory, R.A.

    1977-01-01

    In this study, we make a comparative study of the power supplies required by interior and exterior [to the toroidal field (TF) coils] equilibrium field coils that are separately appropriate for high-β, D-shaped plasmas in TNS. It is shown that the interior coils need power supplies that are an order of magnitude below those required by the exterior coils (while the latter case is much less difficult to build than the former). A hybrid EF coil concept is proposed that combines the interior and the exterior coils to retain their advantages in avoiding large interior coils while lowering the power supplied to the exterior coils by an order of magnitude

  6. Testing of the European LCT coil in the TOSKA facility

    International Nuclear Information System (INIS)

    Herz, W.; Katheder, H.; Krauth, H.

    1985-01-01

    The EURATOM-LCT coil was tested as a single coil in TOSKA. Load cells were mounted in the support structure to monitor forces between coil and vacuum vessel during cooldown and coil charging. Disturbances of components by magnetic fringing fields were carefully considered. To investigate the mechanical behaviour and compare it with FEM-calculations the coil was equipped with strain gauge rosettes and displacement transducers. Van Mises stresses in the coil case are in agreement with calculations. As known from special investigations during coil manufacturing the average radial Young modulus varies along the periphery caused by the different curvatures. This leads to differences with FEM-calculation (larger gaps between winding and coil case) assuming a larger constant Young modulus performed at the beginning of the project

  7. A history of detachable coils: 1987-2012.

    Science.gov (United States)

    Hui, Ferdinand K; Fiorella, David; Masaryk, Thomas J; Rasmussen, Peter A; Dion, Jacques E

    2014-03-01

    The development of detachable coils is one of the most pivotal developments in neurointervention, providing a tool that could be used to treat a wide variety of hemorrhagic stroke. From the original Guglielmi detachable coil, a number of different coil designs and delivery designs have evolved. This article reviews the history of commercially available detachable coils. A timeline of detachable coils was constructed and coil design philosophies were reviewed. A complete list of commercially available coils is presented in a timeline format. Detachable coil technology continues to evolve. Advances in construction and design have yielded products which may benefit patients in terms of safety, radiation dose reduction and cost of treatment. Continued evolution is expected, irrespective of competing disruptive technologies.

  8. Superconducting coil design for a tokamak experimental power reactor

    International Nuclear Information System (INIS)

    Turner, L.R.; Wang, S.T.; Smelser, P.

    1977-01-01

    Superconducting toroidal field (TF) and polodial-field (PF) coils have been designed for the proposed Argonne National Laboratory experimental power reactor (EPR). Features of the design include: (1) Peak field of 8 T at 4.2 K or 10 T at 3.0 K. (2) Constant-tension shape for the TF coils, corrected for the finite number (16) of coils. (3) Analysis of errors in coil alignment. (4) Comparison of safety aspects of series-connected and parallel-connected coils. (5) A 60 kA sheet conductor of NbTi with copper stabilizer and stainless steel for support. (6) Superconducting PF coils outside the TF coils. (7) The TF coils shielded from pulsed fields by high-purity aluminum

  9. Mechanical design of a high field common coil magnet

    CERN Document Server

    Caspi, S; Dietderich, D R; Gourlay, S A; Gupta, R; McInturff, A; Millos, G; Scanlan, R M

    1999-01-01

    A common coil design for high field 2-in-1 accelerator magnets has been previously presented as a "conductor-friendly" option for high field magnets applicable for a Very Large Hadron Collider. This paper presents the mechanical design for a 14 tesla 2-in-1 dipole based on the common coil design approach. The magnet will use a high current density Nb/sub 3/Sn conductor. The design addresses mechanical issues particular to the common coil geometry: horizontal support against coil edges, vertical preload on coil faces, end loading and support, and coil stresses and strains. The magnet is the second in a series of racetrack coil magnets that will provide experimental verification of the common coil design approach. (9 refs).

  10. Testing electrical insulation of LCT coils and instrumentation

    International Nuclear Information System (INIS)

    Luton, J.N.; Ulbricht, A.R.; Ellis, J.F.; Shen, S.S.; Wilson, C.T.; Okuno, K.; Siewerdt, L.O.; Zahn, G.R.; Zichy, J.A.

    1986-09-01

    Three of the superconducting test coils in the Large Coil Task (LCT) use conductors cooled internally by forced flow of helium. In the other three coils, the conductors are cooled externally by a bath of helium. The coils and facility are designed for rapid discharges (dumps) at voltages up to 2.5 kV, depending on coil design. Many coil sensors are connected electrically to the conductors. These sensor leads and signal conditioning equipment also experience high voltage. High-potential tests of ground insulation were performed on all components of the International Fusion Superconducting Magnet Test Facility (IFSMTF). Coil insulation was also tested by ring-down tests that produced voltage distributions within the coils like those occurring during rapid discharge. Methods were developed to localize problem areas and to eliminate them. The effect on breakdown voltage near the Paschen minimum of magnetic fields up to 2 T was investigated

  11. Development of an YBCO coil with SSTC conductors for high field application

    Science.gov (United States)

    Shi, Y.; Liu, H. J.; Liu, F.; Tan, Y. F.; Jin, H.; Yu, M.; Lei, L.; Guo, L.; Hong, Z. Y.

    2018-07-01

    With the continuous reduction of the production costs and improvement of the transport performance, YBCO coated conductor is the most promising candidate for the high field magnet application due to its high irreversibility field and strong mechanical properties. Presently a stable production capacity of the YBCO conductors has been achieved by Shanghai Superconducting Technology Co., Ltd (SSTC) in China. Therefore, the demand in high field application with YBCO conductors is growing in China. This paper describes the design, fabrication and preliminary experiment of a solenoid coil with YBCO conductors supplied by SSTC to validate the possibility of high field application. Four same double pancakes were manufactured and assembled for the YBCO coil where the outer diameter and height was 54.3 and 48 mm respectively to match the dimensional limitation of the 14 T background magnets. The critical current (Ic) of YBCO conductors was obtained by measuring as a function of the applied field perpendicular to the YBCO conductor surface which provides the necessary input parameters for preliminary performance evaluation of the coil. Finally the preliminary test and discussion at 77 and 4.2 K were carried out. The consistency of four double pancakes Ic was achieved. The measured results indicate that the fabrication technology of HTS coil is reliable which gives the conference for the in-field test in high field application. This YBCO coil is the first demonstration of the SSTC YBCO coated conductors.

  12. GBNV encoded movement protein (NSm) remodels ER network via C-terminal coiled coil domain

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pratibha; Savithri, H.S., E-mail: bchss@biochem.iisc.ernet.in

    2015-08-15

    Plant viruses exploit the host machinery for targeting the viral genome–movement protein complex to plasmodesmata (PD). The mechanism by which the non-structural protein m (NSm) of Groundnut bud necrosis virus (GBNV) is targeted to PD was investigated using Agrobacterium mediated transient expression of NSm and its fusion proteins in Nicotiana benthamiana. GFP:NSm formed punctuate structures that colocalized with mCherry:plasmodesmata localized protein 1a (PDLP 1a) confirming that GBNV NSm localizes to PD. Unlike in other movement proteins, the C-terminal coiled coil domain of GBNV NSm was shown to be involved in the localization of NSm to PD, as deletion of this domain resulted in the cytoplasmic localization of NSm. Treatment with Brefeldin A demonstrated the role of ER in targeting GFP NSm to PD. Furthermore, mCherry:NSm co-localized with ER–GFP (endoplasmic reticulum targeting peptide (HDEL peptide fused with GFP). Co-expression of NSm with ER–GFP showed that the ER-network was transformed into vesicles indicating that NSm interacts with ER and remodels it. Mutations in the conserved hydrophobic region of NSm (residues 130–138) did not abolish the formation of vesicles. Additionally, the conserved prolines at positions 140 and 142 were found to be essential for targeting the vesicles to the cell membrane. Further, systematic deletion of amino acid residues from N- and C-terminus demonstrated that N-terminal 203 amino acids are dispensable for the vesicle formation. On the other hand, the C-terminal coiled coil domain when expressed alone could also form vesicles. These results suggest that GBNV NSm remodels the ER network by forming vesicles via its interaction through the C-terminal coiled coil domain. Interestingly, NSm interacts with NP in vitro and coexpression of these two proteins in planta resulted in the relocalization of NP to PD and this relocalization was abolished when the N-terminal unfolded region of NSm was deleted. Thus, the NSm

  13. Compressing DNA sequence databases with coil

    Directory of Open Access Journals (Sweden)

    Hendy Michael D

    2008-05-01

    Full Text Available Abstract Background Publicly available DNA sequence databases such as GenBank are large, and are growing at an exponential rate. The sheer volume of data being dealt with presents serious storage and data communications problems. Currently, sequence data is usually kept in large "flat files," which are then compressed using standard Lempel-Ziv (gzip compression – an approach which rarely achieves good compression ratios. While much research has been done on compressing individual DNA sequences, surprisingly little has focused on the compression of entire databases of such sequences. In this study we introduce the sequence database compression software coil. Results We have designed and implemented a portable software package, coil, for compressing and decompressing DNA sequence databases based on the idea of edit-tree coding. coil is geared towards achieving high compression ratios at the expense of execution time and memory usage during compression – the compression time represents a "one-off investment" whose cost is quickly amortised if the resulting compressed file is transmitted many times. Decompression requires little memory and is extremely fast. We demonstrate a 5% improvement in compression ratio over state-of-the-art general-purpose compression tools for a large GenBank database file containing Expressed Sequence Tag (EST data. Finally, coil can efficiently encode incremental additions to a sequence database. Conclusion coil presents a compelling alternative to conventional compression of flat files for the storage and distribution of DNA sequence databases having a narrow distribution of sequence lengths, such as EST data. Increasing compression levels for databases having a wide distribution of sequence lengths is a direction for future work.

  14. Trends in tungsten coil atomic spectrometry

    Science.gov (United States)

    Donati, George L.

    Renewed interest in electrothermal atomic spectrometric methods based on tungsten coil atomizers is a consequence of a world wide increasing demand for fast, inexpensive, sensitive, and portable analytical methods for trace analysis. In this work, tungsten coil atomic absorption spectrometry (WCAAS) and tungsten coil atomic emission spectrometry (WCAES) are used to determine several different metals and even a non-metal at low levels in different samples. Improvements in instrumentation and new strategies to reduce matrix effects and background signals are presented. Investigation of the main factors affecting both WCAAS and WCAES analytical signals points to the importance of a reducing, high temperature gas phase in the processes leading to atomic cloud generation. Some more refractory elements such as V and Ti were determined for the first time by double tungsten coil atomic emission spectrometry (DWCAES). The higher temperatures provided by two atomizers in DWCAES also allowed the detection of Ag, Cu and Sn emission signals for the first time. Simultaneous determination of several elements by WCAES in relatively complex sample matrices was possible after a simple acid extraction. The results show the potential of this method as an alternative to more traditional, expensive methods for fast, more effective analyses and applications in the field. The development of a new metallic atomization cell is also presented. Lower limits of detection in both WCAAS and WCAES determinations were obtained due to factors such as better control of background signal, smaller, more isothermal system, with atomic cloud concentration at the optical path for a longer period of time. Tungsten coil-based methods are especially well suited to applications requiring low sample volume, low cost, sensitivity and portability. Both WCAAS and WCAES have great commercial potential in fields as diverse as archeology and industrial quality control. They are simple, inexpensive, effective

  15. Superconductive magnet having shim coils and quench protection circuits

    International Nuclear Information System (INIS)

    Schwall, R.E.

    1987-01-01

    A superconductive magnet is described comprising: a first persistent current loop comprising a first superconductor and a main coil connected to the first superconductor, the main coil being operative in response to superconduction therein to generate a primary magnetic field; a second persistent current loop comprising a second superconductor and a shim coil connected thereto, the shim coil being operative in response to superconduction therein to generate a corrective field for correcting aberrations in a predetermined gradient in the primary magnetic field, the shim coil having fewer turns than the main coil and being inductively coupled therewith whereby small changes in the current in the main coil cause much greater changes in the current in the shim coil. The magnet is characterized by an improvement which consists of: a first heater connected across the second persistent loop in parallel with the shim coil, the first heater being normally inoperative to carry current while the shim coil and the second superconductor are superconducting, the first heater being operative in response to current therein to heat the shim coil to a resistive state; and protective circuit means comprising a second heater connected to the main coil for carrying current from the main coil upon quenching of the main coil, the second heater being disposed in thermal contact with the second superconductor to heat the second superconductor to a resistive state in response to the current from the main coil to thereby divert current in the second persistent loop through the second heater causing it to heat the shim coil to a resistive state and resistively dissipate energy therein

  16. Comparison of edge plasma perturbation during ELM control using one vs. two toroidal rows of RMP coils in ITER similar shaped plasmas on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Fenstermacher, M.E., E-mail: fenstermacher@fusion.gat.co [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Evans, T.E.; Osborne, T.H.; Schaffer, M.J.; DeGrassie, J.S.; Gohil, P.; Groebner, R.J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Moyer, R.A. [University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093 (United States)

    2009-06-15

    Large Type-I edge localized modes (ELMs) were suppressed by n = 3 resonant magnetic perturbations (RMPs) from a set of internal coils in plasmas with an ITER similar shape at the ITER pedestal collisionality, nu{sub e}*approx0.1 and low edge safety factor (q{sub 95} approx 3.6), with either a single toroidal row of the internal RMP coils or two poloidally separated rows of coils. ELM suppression with a single row of internal coils was achieved at approximately the same q{sub 95} surface-averaged perturbation field as with two rows of coils, but required higher current per coil. Maintaining complete suppression of ELMs using n = 3 RMPs from a single toroidal row of internal coils was less robust to variations in input neutral beam injection torque than previous ELM suppression cases using both rows of internal coils. With either configuration of RMP coils, maximum ELM size is correlated with the width of the edge region having good overlap of the magnetic islands from vacuum field calculations.

  17. Plasmodium vivax antigen discovery based on alpha-helical coiled coil protein motif.

    Directory of Open Access Journals (Sweden)

    Nora Céspedes

    Full Text Available Protein α-helical coiled coil structures that elicit antibody responses, which block critical functions of medically important microorganisms, represent a means for vaccine development. By using bioinformatics algorithms, a total of 50 antigens with α-helical coiled coil motifs orthologous to Plasmodium falciparum were identified in the P. vivax genome. The peptides identified in silico were chemically synthesized; circular dichroism studies indicated partial or high α-helical content. Antigenicity was evaluated using human sera samples from malaria-endemic areas of Colombia and Papua New Guinea. Eight of these fragments were selected and used to assess immunogenicity in BALB/c mice. ELISA assays indicated strong reactivity of serum samples from individuals residing in malaria-endemic regions and sera of immunized mice, with the α-helical coiled coil structures. In addition, ex vivo production of IFN-γ by murine mononuclear cells confirmed the immunogenicity of these structures and the presence of T-cell epitopes in the peptide sequences. Moreover, sera of mice immunized with four of the eight antigens recognized native proteins on blood-stage P. vivax parasites, and antigenic cross-reactivity with three of the peptides was observed when reacted with both the P. falciparum orthologous fragments and whole parasites. Results here point to the α-helical coiled coil peptides as possible P. vivax malaria vaccine candidates as were observed for P. falciparum. Fragments selected here warrant further study in humans and non-human primate models to assess their protective efficacy as single components or assembled as hybrid linear epitopes.

  18. Coiled-coil forming peptides for the induction of silver nanoparticles

    International Nuclear Information System (INIS)

    Božič Abram, Sabina; Aupič, Jana; Dražić, Goran; Gradišar, Helena; Jerala, Roman

    2016-01-01

    Biopolymers with defined sequence patterns offer an attractive alternative for the formation of silver nanoparticle (AgNP). A set of coiled-coil dimer forming peptides was tested for their AgNP formation ability. Seventeen of those peptides mediated the formation of AgNPs in aqueous solution at neutral pH, while the formation of a coiled-coil dimer inhibited the nanoparticle generation. A QSAR regression model on the relationship between sequence and function suggests that in this peptide type the patterns KXQQ and KXEE are favorable, whereas Ala residues appear to have an inhibitory effect. UV–VIS spectra of the obtained nanoparticles gave a peak at around 420 nm, typical for AgNPs in the size range around 40 nm, which was confirmed by dynamic light scattering and transmission electron microscopy. Peptide-induced AgNPs exhibited good antibacterial activity, even after a 15 min contact time, while they had low toxicity to human cells at the same concentrations. These results show that our designed peptides generate AgNPs with antibacterial activity at mild conditions and might be used for antibacterial coatings. - Highlights: • 17 of the 30 tested coiled-coil forming peptides induce AgNP formation. • Coiled-coil dimer formation suppresses AgNP generation of individual peptides. • Size of the peptide-induced silver nanoparticles is around 40 nm. • QSAR analysis points to the importance of KXQQ and KXEE motifs for AgNP generation. • Peptide-induced silver nanoparticles exhibit antibacterial activity.

  19. CCBuilder 2.0: Powerful and accessible coiled-coil modeling.

    Science.gov (United States)

    Wood, Christopher W; Woolfson, Derek N

    2018-01-01

    The increased availability of user-friendly and accessible computational tools for biomolecular modeling would expand the reach and application of biomolecular engineering and design. For protein modeling, one key challenge is to reduce the complexities of 3D protein folds to sets of parametric equations that nonetheless capture the salient features of these structures accurately. At present, this is possible for a subset of proteins, namely, repeat proteins. The α-helical coiled coil provides one such example, which represents ≈ 3-5% of all known protein-encoding regions of DNA. Coiled coils are bundles of α helices that can be described by a small set of structural parameters. Here we describe how this parametric description can be implemented in an easy-to-use web application, called CCBuilder 2.0, for modeling and optimizing both α-helical coiled coils and polyproline-based collagen triple helices. This has many applications from providing models to aid molecular replacement for X-ray crystallography, in silico model building and engineering of natural and designed protein assemblies, and through to the creation of completely de novo "dark matter" protein structures. CCBuilder 2.0 is available as a web-based application, the code for which is open-source and can be downloaded freely. http://coiledcoils.chm.bris.ac.uk/ccbuilder2. We have created CCBuilder 2.0, an easy to use web-based application that can model structures for a whole class of proteins, the α-helical coiled coil, which is estimated to account for 3-5% of all proteins in nature. CCBuilder 2.0 will be of use to a large number of protein scientists engaged in fundamental studies, such as protein structure determination, through to more-applied research including designing and engineering novel proteins that have potential applications in biotechnology. © 2017 The Authors Protein Science published by Wiley Periodicals, Inc. on behalf of The Protein Society.

  20. Coiled-coil forming peptides for the induction of silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Božič Abram, Sabina [Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); Graduate School of Biomedicine, University of Ljubljana, Ljubljana 1000 (Slovenia); Aupič, Jana [Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); Doctoral Programme in Chemical Sciences, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000 (Slovenia); Dražić, Goran [Laboratory for Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); Gradišar, Helena [Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); EN-FIST, Centre of Excellence, Trg Osvobodilne fronte 13, Ljubljana 1000 (Slovenia); Jerala, Roman, E-mail: roman.jerala@ki.si [Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia); EN-FIST, Centre of Excellence, Trg Osvobodilne fronte 13, Ljubljana 1000 (Slovenia)

    2016-04-08

    Biopolymers with defined sequence patterns offer an attractive alternative for the formation of silver nanoparticle (AgNP). A set of coiled-coil dimer forming peptides was tested for their AgNP formation ability. Seventeen of those peptides mediated the formation of AgNPs in aqueous solution at neutral pH, while the formation of a coiled-coil dimer inhibited the nanoparticle generation. A QSAR regression model on the relationship between sequence and function suggests that in this peptide type the patterns KXQQ and KXEE are favorable, whereas Ala residues appear to have an inhibitory effect. UV–VIS spectra of the obtained nanoparticles gave a peak at around 420 nm, typical for AgNPs in the size range around 40 nm, which was confirmed by dynamic light scattering and transmission electron microscopy. Peptide-induced AgNPs exhibited good antibacterial activity, even after a 15 min contact time, while they had low toxicity to human cells at the same concentrations. These results show that our designed peptides generate AgNPs with antibacterial activity at mild conditions and might be used for antibacterial coatings. - Highlights: • 17 of the 30 tested coiled-coil forming peptides induce AgNP formation. • Coiled-coil dimer formation suppresses AgNP generation of individual peptides. • Size of the peptide-induced silver nanoparticles is around 40 nm. • QSAR analysis points to the importance of KXQQ and KXEE motifs for AgNP generation. • Peptide-induced silver nanoparticles exhibit antibacterial activity.

  1. Coiled coil peptides as universal linkers for the attachment of recombinant proteins to polymer therapeutics

    Czech Academy of Sciences Publication Activity Database

    Pechar, Michal; Pola, Robert; Laga, Richard; Ulbrich, Karel; Bednárová, Lucie; Maloň, Petr; Sieglová, Irena; Král, Vlastimil; Fábry, Milan; Vaněk, O.

    2011-01-01

    Roč. 12, č. 10 (2011), s. 3645-3655 ISSN 1525-7797 R&D Projects: GA ČR GA203/08/0543; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z40550506; CEZ:AV0Z50520514 Keywords : coiled coil * polymer the rapeutics * drug targeting Subject RIV: CC - Organic Chemistry Impact factor: 5.479, year: 2011

  2. Field load and displacement boundary condition computer program used for the finite element analysis and design of toroidal field coils in a tokamak

    International Nuclear Information System (INIS)

    Smith, R.A.

    1975-06-01

    The design evaluation of toroidal field coils on the Princeton Large Torus (PLT), the Poloidal Diverter Experiment (PDX) and the Tokamak Fusion Test Reactor (TFTR) has been performed by structural analysis with the finite element method. The technique employed has been simplified with supplementary computer programs that are used to generate the input data for the finite element computer program. Significant automation has been provided by computer codes in three areas of data input. These are the definition of coil geometry by a mesh of node points, the definition of finite elements via the node points and the definition of the node point force/displacement boundary conditions. The computer programs by name that have been used to perform the above functions are PDXNODE, ELEMENT and PDXFORC. The geometric finite element modeling options for toroidal field coils provided by PDXNODE include one-fourth or one-half symmetric sections of circular coils, oval shaped coils or dee-shaped coils with or without a beveled wedging surface. The program ELEMENT which defines the finite elements for input to the finite element computer code can provide considerable time and labor savings when defining the model of coils of non-uniform cross-section or when defining the model of coils whose material properties are different in the R and THETA directions due to the laminations of alternate epoxy and copper windings. The modeling features provided by the program ELEMENT have been used to analyze the PLT and the TFTR toroidal field coils with integral support structures. The computer program named PDXFORC is described. It computes the node point forces in a model of a toroidal field coil from the vector crossproduct of the coil current and the magnetic field. The model can be of one-half or one-fourth symmetry to be consistent with the node model defined by PDXNODE, and the magnetic field is computed from toroidal or poloidal coils

  3. Transport of one SC coil through the village of Meyrin

    CERN Multimedia

    1956-01-01

    The energizing coils of the Synchro-cyclotron magnet were manufactured in Belgium before travelling to Basel in Switzerland by boat and continuing by road to Geneva. The first coil reached Geneva in December 1955, with the second following in early 1956. The coils were stored in a hangar at the Geneva airport before they were brought to CERN in May 1956.

  4. Strain and stress of the ASDEX multipole magnetic coils

    International Nuclear Information System (INIS)

    Jandl, O.; Pillsticker, M.

    1978-01-01

    A brief description of the technical concept of the multipole magnetic field coils for the ASDEX tokamak is given. The various loads of the coils are explained in quality. To compute displacement and stress of the coils FEM computer programs are used. The computing models applied to this problem are founded and the results and the conclusions are reported. (orig.) [de

  5. Mechanical study of 20 MJ superconducting pulse coil

    International Nuclear Information System (INIS)

    Hattori, Yasuhide; Shimamoto, Susumu

    1985-09-01

    This paper describes calculation methods and computer codes of stress distribution in a circular-shaped superconducting pulsed coils. The stress problems of a large sized superconducting coil, for example, are discussed for 20 MJ pool-cooled pulse coil. Young's modulus of a stranded flat cable, low rigidity, is measured and evaluated. (author)

  6. Effects of Gradient Coil Noise and Gradient Coil Replacement on the Reproducibility of Resting State Networks.

    Science.gov (United States)

    Bagarinao, Epifanio; Tsuzuki, Erina; Yoshida, Yukina; Ozawa, Yohei; Kuzuya, Maki; Otani, Takashi; Koyama, Shuji; Isoda, Haruo; Watanabe, Hirohisa; Maesawa, Satoshi; Naganawa, Shinji; Sobue, Gen

    2018-01-01

    The stability of the MRI scanner throughout a given study is critical in minimizing hardware-induced variability in the acquired imaging data set. However, MRI scanners do malfunction at times, which could generate image artifacts and would require the replacement of a major component such as its gradient coil. In this article, we examined the effect of low intensity, randomly occurring hardware-related noise due to a faulty gradient coil on brain morphometric measures derived from T1-weighted images and resting state networks (RSNs) constructed from resting state functional MRI. We also introduced a method to detect and minimize the effect of the noise associated with a faulty gradient coil. Finally, we assessed the reproducibility of these morphometric measures and RSNs before and after gradient coil replacement. Our results showed that gradient coil noise, even at relatively low intensities, could introduce a large number of voxels exhibiting spurious significant connectivity changes in several RSNs. However, censoring the affected volumes during the analysis could minimize, if not completely eliminate, these spurious connectivity changes and could lead to reproducible RSNs even after gradient coil replacement.

  7. Strong contributions from vertical triads to helix-partner preferences in parallel coiled coils.

    Science.gov (United States)

    Steinkruger, Jay D; Bartlett, Gail J; Woolfson, Derek N; Gellman, Samuel H

    2012-09-26

    Pairing preferences in heterodimeric coiled coils are determined by complementarities among side chains that pack against one another at the helix-helix interface. However, relationships between dimer stability and interfacial residue identity are not fully understood. In the context of the "knobs-into-holes" (KIH) packing pattern, one can identify two classes of interactions between side chains from different helices: "lateral", in which a line connecting the adjacent side chains is perpendicular to the helix axes, and "vertical", in which the connecting line is parallel to the helix axes. We have previously analyzed vertical interactions in antiparallel coiled coils and found that one type of triad constellation (a'-a-a') exerts a strong effect on pairing preferences, while the other type of triad (d'-d-d') has relatively little impact on pairing tendencies. Here, we ask whether vertical interactions (d'-a-d') influence pairing in parallel coiled-coil dimers. Our results indicate that vertical interactions can exert a substantial impact on pairing specificity, and that the influence of the d'-a-d' triad depends on the lateral a' contact within the local KIH motif. Structure-informed bioinformatic analyses of protein sequences reveal trends consistent with the thermodynamic data derived from our experimental model system in suggesting that heterotriads involving Leu and Ile are preferred over homotriads involving Leu and Ile.

  8. Historical review: another 50th anniversary--new periodicities in coiled coils.

    Science.gov (United States)

    Gruber, Markus; Lupas, Andrei N

    2003-12-01

    In 1953, Francis Crick and Linus Pauling both proposed models of supercoiled alpha helices ('coiled coils') for the structure of keratin. These were the first attempts at modelling the tertiary structure of a protein. Crick emphasized the packing mode of the side-chains ('knobs-into-holes'), which required a periodicity of seven residues over two helical turns (7/2) and a supercoil in the opposite sense of the constituent helices. By contrast, Pauling envisaged a broader set of periodicities (4/1, 7/2, 18/5, 15/4, 11/3) and supercoils of both senses. Crick's model became canonical and the 'heptad repeat' essentially synonymous with coiled coils, but 50 years later new crystal structures and protein sequences show that the less common periodicities envisaged by Pauling also occur in coiled coils, adding a variant packing mode ('knobs-to-knobs') to the standard model. Pauling's laboratory notebooks suggest that he searched unsuccessfully for this packing mode in 1953.

  9. Coiled-Coil Proteins Facilitated the Functional Expansion of the Centrosome

    Science.gov (United States)

    Kuhn, Michael; Hyman, Anthony A.; Beyer, Andreas

    2014-01-01

    Repurposing existing proteins for new cellular functions is recognized as a main mechanism of evolutionary innovation, but its role in organelle evolution is unclear. Here, we explore the mechanisms that led to the evolution of the centrosome, an ancestral eukaryotic organelle that expanded its functional repertoire through the course of evolution. We developed a refined sequence alignment technique that is more sensitive to coiled coil proteins, which are abundant in the centrosome. For proteins with high coiled-coil content, our algorithm identified 17% more reciprocal best hits than BLAST. Analyzing 108 eukaryotic genomes, we traced the evolutionary history of centrosome proteins. In order to assess how these proteins formed the centrosome and adopted new functions, we computationally emulated evolution by iteratively removing the most recently evolved proteins from the centrosomal protein interaction network. Coiled-coil proteins that first appeared in the animal–fungi ancestor act as scaffolds and recruit ancestral eukaryotic proteins such as kinases and phosphatases to the centrosome. This process created a signaling hub that is crucial for multicellular development. Our results demonstrate how ancient proteins can be co-opted to different cellular localizations, thereby becoming involved in novel functions. PMID:24901223

  10. A special correcting winding for the l = 2 torsatron with split-type helical coils

    International Nuclear Information System (INIS)

    Kotenko, V.G.

    2012-01-01

    A split-type special correcting winding (split-type SCW) for the l = 2 torsatron toroidal magnetic system with split-type helical coils is considered. The split-type SCW gives the possibility of controlling the position of the magnetic surface configuration in the direction perpendicular to the torus equatorial plane. Numerical simulations were carried out to investigate the influence of the split-type SCW magnetic field on centered and distant relative to the torus surface magnetic surface configuration with a plane magnetic axis, being promising for the fusion reactor. The configuration is realized in the l = 2 torsatron with split-type helical coils and with the coils of an additional toroidal magnetic field. The calculations show that the split-type SCW magnetic field influence on the initial magnetic surface configuration leads mainly to the magnetic surface configuration displacement along the straight z axis of torus rotation. The displacement of ∼0.1a, a is the minor radius of the torus, has no critical effect on the magnetic surface parameters. An idea on the split-type SCW magnetic field structure is obtained by numerical simulations of the effect of this field as a minority magnetic field imposed on the magnetic field of a well-known configuration. The split-type SCW magnetic field is directed, predominantly along the major radius of the torus within its volume. The displacement range of the closed magnetic surface configuration depends on the split-type SCW magnetic field value.

  11. Dielectric properties of 3D-printed materials for anatomy specific 3D-printed MRI coils

    Science.gov (United States)

    Behzadnezhad, Bahareh; Collick, Bruce D.; Behdad, Nader; McMillan, Alan B.

    2018-04-01

    Additive manufacturing provides a low-cost and rapid means to translate 3D designs into the construction of a prototype. For MRI, this type of manufacturing can be used to construct various components including the structure of RF coils. In this paper, we characterize the material properties (dielectric constant and loss tangent) of several common 3D-printed polymers in the MRI frequency range of 63-300 MHz (for MRI magnetic field strengths of 1.5-7 T), and utilize these material properties in full-wave electromagnetic simulations to design and construct a very low-cost subject/anatomy-specific 3D-printed receive-only RF coil that fits close to the body. We show that the anatomy-specific coil exhibits higher signal-to-noise ratio compared to a conventional flat surface coil.

  12. Scalable Nernst thermoelectric power using a coiled galfenol wire

    Science.gov (United States)

    Yang, Zihao; Codecido, Emilio A.; Marquez, Jason; Zheng, Yuanhua; Heremans, Joseph P.; Myers, Roberto C.

    2017-09-01

    The Nernst thermopower usually is considered far too weak in most metals for waste heat recovery. However, its transverse orientation gives it an advantage over the Seebeck effect on non-flat surfaces. Here, we experimentally demonstrate the scalable generation of a Nernst voltage in an air-cooled metal wire coiled around a hot cylinder. In this geometry, a radial temperature gradient generates an azimuthal electric field in the coil. A Galfenol (Fe0.85Ga0.15) wire is wrapped around a cartridge heater, and the voltage drop across the wire is measured as a function of axial magnetic field. As expected, the Nernst voltage scales linearly with the length of the wire. Based on heat conduction and fluid dynamic equations, finite-element method is used to calculate the temperature gradient across the Galfenol wire and determine the Nernst coefficient. A giant Nernst coefficient of -2.6 μV/KT at room temperature is estimated, in agreement with measurements on bulk Galfenol. We expect that the giant Nernst effect in Galfenol arises from its magnetostriction, presumably through enhanced magnon-phonon coupling. Our results demonstrate the feasibility of a transverse thermoelectric generator capable of scalable output power from non-flat heat sources.

  13. Ultrasound generation with high power and coil only EMAT concepts.

    Science.gov (United States)

    Rueter, Dirk; Morgenstern, Tino

    2014-12-01

    Electro-magnetic acoustic transducers (EMATs) are intended as non-contact and non-destructive ultrasound transducers for metallic material. The transmitted intensities from EMATS are modest, particularly at notable lift off distances. Some time ago a concept for a "coil only EMAT" was presented, without static magnetic field. In this contribution, such compact "coil only EMATs" with effective areas of 1-5cm(2) were driven to excessive power levels at MHz frequencies, using pulsed power technologies. RF induction currents of 10kA and tens of Megawatts are applied. With increasing power the electroacoustic conversion efficiency also increases. The total effect is of second order or quadratic, therefore non-linear and progressive, and yields strong ultrasound signals up to kW/cm(2) at MHz frequencies in the metal. Even at considerable lift off distances (cm) the ultrasound can be readily detected. Test materials are aluminum, ferromagnetic steel and stainless steel (non-ferromagnetic). Thereby, most metal types are represented. The technique is compared experimentally with other non-contact methods: laser pulse induced ultrasound and spark induced ultrasound, both damaging to the test object's surface. At small lift off distances, the intensity from this EMAT concept clearly outperforms the laser pulses or heavy spark impacts. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Scalable Nernst thermoelectric power using a coiled galfenol wire

    Directory of Open Access Journals (Sweden)

    Zihao Yang

    2017-09-01

    Full Text Available The Nernst thermopower usually is considered far too weak in most metals for waste heat recovery. However, its transverse orientation gives it an advantage over the Seebeck effect on non-flat surfaces. Here, we experimentally demonstrate the scalable generation of a Nernst voltage in an air-cooled metal wire coiled around a hot cylinder. In this geometry, a radial temperature gradient generates an azimuthal electric field in the coil. A Galfenol (Fe0.85Ga0.15 wire is wrapped around a cartridge heater, and the voltage drop across the wire is measured as a function of axial magnetic field. As expected, the Nernst voltage scales linearly with the length of the wire. Based on heat conduction and fluid dynamic equations, finite-element method is used to calculate the temperature gradient across the Galfenol wire and determine the Nernst coefficient. A giant Nernst coefficient of -2.6 μV/KT at room temperature is estimated, in agreement with measurements on bulk Galfenol. We expect that the giant Nernst effect in Galfenol arises from its magnetostriction, presumably through enhanced magnon-phonon coupling. Our results demonstrate the feasibility of a transverse thermoelectric generator capable of scalable output power from non-flat heat sources.

  15. MR imaging of colorectal carcinomas using an MR endoscopic coil

    International Nuclear Information System (INIS)

    Murano, Akihiko; Kido, Choichiro; Sasaki, Fumio; Nakamura, Tsuneya; Kobayashi, Semi; Katoh, Tomoyuki; Hirai, Takashi

    1994-01-01

    Diagnosis of the depth of wall invasion by rectal carcinoma using MR endoscopy was performed in ten resected specimens, including five rectal carcinomas, three colon carcinomas, two normal gastric wall. In addition, the gastric wall of a pig was examined. MR imaging was done with a 1.5-T Signa Advantage (GE Medical System) system, with the surface coil of the MR endoscope acting as the receiver coil. Five layers could be distinguished in the bowel wall: mucosa, submucosa and muscularis propria divided into circular muscle, longitudinal muscle and intervening connective tissue. Tumors had almost the same signal intensity as muscle. The MR images of colon carcinomas, rectal carcinomas, and extrinsically metastatic involvement of the sigmoid colon by rectal carcinoma all correlated well with the pathological findings. The normal structure of the gastric wall was similar to that of the colon. 3D-fast Spoiled Grass (SPGR) sequence has a fairly short scanning time. Thus, the possibility of precise clinical diagnosis by this method was suggested. (author)

  16. Tolerance Evaluation of Poloidal Shear Keys for ITER TF Coil

    International Nuclear Information System (INIS)

    Fu Youkun; Neil, M.; Cees Jong

    2006-01-01

    There are 18 ITER Toroidal Field (TF) Coils. Unlike the other ITER coils, these coils are structurally linked. These links consist of friction between the coil legs in the central vault formed by the inner straight legs of the coils, four outer inter-coil structures (OIS) and one inner inter-coil structure (IIS). The OIS consists essentially of bands around all 18 coils to provide shear support by forming shear panels with the coil case, and the IIS consists of poloidal circular keys placed directly between the coil cases. Global analysis of the 'perfect' coil shape has shown high stresses in the IIS, in the poloidal keyways. Optimization has successfully reduced these stresses to acceptable values as regards the expected fatigue resistance. However it is necessary to confirm that the stresses are still acceptable when realistic values of geometry variations are included (i.e. the effect of coil and case tolerances). Because of the extensive mechanical links between coils the poloidal key stresses can also be affected by tolerances elsewhere in the case. As the first step in assessment of the possible variations in stresses, a substructure technique is being used to develop a local model of the key region. The result of geometry variations between individual coils is a loss in the 18 fold symmetry used to simplify previous analyses. With the new and optimized model it should be possible to relax the 18-fold symmetry, but a full analysis of all 18 coils is still not possible. Systematic ways of representing the tolerance variation in the finite element model have been developed so that parametric studies can be undertaken without a full reconstruction of the model. (author)

  17. Unraveling double stranded alpha-helical coiled coils: an x-ray diffraction study on hard alpha-keratin fibers.

    Science.gov (United States)

    Kreplak, L; Doucet, J; Briki, F

    2001-04-15

    Transformations of proteins secondary and tertiary structures are generally studied in globular proteins in solution. In fibrous proteins, such as hard alpha-keratin, that contain long and well-defined double stranded alpha-helical coiled coil domains, such study can be directly done on the native fibrous tissue. In order to assess the structural behavior of the coiled coil domains under an axial mechanical stress, wide angle x-ray scattering and small angle x-ray scattering experiments have been carried out on stretched horse hair fibers at relative humidity around 30%. Our observations of the three major axial spacings as a function of the applied macroscopic strain have shown two rates. Up to 4% macroscopic strain the coiled coils were slightly distorted but retained their overall conformation. Above 4% the proportion of coiled coil domains progressively decreased. The main and new result of our study is the observation of the transition from alpha-helical coiled coils to disordered chains instead of the alpha-helical coiled coil to beta-sheet transition that occurs in wet fibers.

  18. Study on the performance improvement of the high temperature superconducting coil with several separated coils at the edges

    International Nuclear Information System (INIS)

    Ishiguri, S.; Oka, T.; Fukui, S.; Ogawa, J.; Sato, T.

    2008-01-01

    In designing high temperature superconducting (HTS) coils, it is important to secure large magnetic fields and stored energy using shorter tape length. Thus, it is necessary to improve the transport current performance of the coils. The critical current and n-value of an HTS tape depend on magnetic fields and flux angles under constant temperature. Considering these dependencies, we established a model to analyze coil critical current. This model clarifies that relatively large electric fields are generated at the coil edges. This adversely affects the transport current performance. In this study, the coil edge is separated into several coils, keeping the total tape length constant. This increases the coil critical current, stored energy, central magnetic field, and also the coil volume, which contains vacancies created by the separation. To estimate coil performance, we calculated the stored energy density, whose denominator is the increased coil volume. This stored energy density reaches its maximum value when the number of the separated coils is eight. At this optimum separation, the central magnetic field increases by 13%, and the stored energy improves by 43%, compared to a rectangular coil wound with the same tape length

  19. CCBuilder: an interactive web-based tool for building, designing and assessing coiled-coil protein assemblies.

    Science.gov (United States)

    Wood, Christopher W; Bruning, Marc; Ibarra, Amaurys Á; Bartlett, Gail J; Thomson, Andrew R; Sessions, Richard B; Brady, R Leo; Woolfson, Derek N

    2014-11-01

    The ability to accurately model protein structures at the atomistic level underpins efforts to understand protein folding, to engineer natural proteins predictably and to design proteins de novo. Homology-based methods are well established and produce impressive results. However, these are limited to structures presented by and resolved for natural proteins. Addressing this problem more widely and deriving truly ab initio models requires mathematical descriptions for protein folds; the means to decorate these with natural, engineered or de novo sequences; and methods to score the resulting models. We present CCBuilder, a web-based application that tackles the problem for a defined but large class of protein structure, the α-helical coiled coils. CCBuilder generates coiled-coil backbones, builds side chains onto these frameworks and provides a range of metrics to measure the quality of the models. Its straightforward graphical user interface provides broad functionality that allows users to build and assess models, in which helix geometry, coiled-coil architecture and topology and protein sequence can be varied rapidly. We demonstrate the utility of CCBuilder by assembling models for 653 coiled-coil structures from the PDB, which cover >96% of the known coiled-coil types, and by generating models for rarer and de novo coiled-coil structures. CCBuilder is freely available, without registration, at http://coiledcoils.chm.bris.ac.uk/app/cc_builder/. © The Author 2014. Published by Oxford University Press.

  20. Physiological Studies on Pea Tendrils. IV. Flavonoids and Contact Coiling

    Science.gov (United States)

    Jaffe, M. J.; Galston, A. W.

    1967-01-01

    Pea tendrils contain high concentrations of flavonoids, mainly quercetin-triglucosyl-p-coumarate (QGC). QGC is most abundant near the highly responsive apex of the tendril, and least abundant at the base. After mechanical stimulation, and during coiling of the tendril, the QGC titer drops to about 30% of its original value. The kinetics of flavonoid disappearance are significantly correlated with the kinetics of coiling. Aqueous extracts of unstimulated pea tendrils or 10 μm QGC inhibit contact coiling of excised tendrils. Extracts of coiled tendrils do not. The evidence indicates a possible regulatory role for flavonoids in contact coiling. PMID:16656581

  1. Superconducting coil system and methods of assembling the same

    Science.gov (United States)

    Rajput-Ghoshal, Renuka; Rochford, James H.; Ghoshal, Probir K.

    2016-01-19

    A superconducting magnet apparatus is provided. The superconducting magnet apparatus includes a power source configured to generate a current; a first switch coupled in parallel to the power source; a second switch coupled in series to the power source; a coil coupled in parallel to the first switch and the second switch; and a passive quench protection device coupled to the coil and configured to by-pass the current around the coil and to decouple the coil from the power source when the coil experiences a quench.

  2. The IEA large coil task test results in IFSMTF

    International Nuclear Information System (INIS)

    Lubell, M.S.; Clinard, J.A.; Dresner, L.

    1987-01-01

    The Large Coil Task (LCT) is an international collaboration of the United States, EURATOM, Japan, and Switzerland to develop large superconducting magnets for fusion reactors. The testing phase of LCT was completed on September 3, 1987. All six coils exceeded the design goals, both as single coils and in six-coil toroidal tests. In addition, a symmetric torus test was performed in which a maximum field of 9 T was reached in all coils simultaneously. These are by far the largest magnets (either in size, weight, or stored energy) ever to achieve such a field. 6 refs., 6 figs., 3 tabs

  3. Random coil chemical shift for intrinsically disordered proteins

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Brander, Søren; Poulsen, Flemming Martin

    2011-01-01

    . Temperature has a non-negligible effect on the (13)C random coil chemical shifts, so temperature coefficients are reported for the random coil chemical shifts to allow extrapolation to other temperatures. The pH dependence of the histidine random coil chemical shifts is investigated in a titration series......, which allows the accurate random coil chemical shifts to be obtained at any pH. By correcting the random coil chemical shifts for the effects of temperature and pH, systematic biases of the secondary chemical shifts are minimized, which will improve the reliability of detection of transient secondary...

  4. SSC [Superconducting Super Collider] dipole coil production tooling

    International Nuclear Information System (INIS)

    Carson, J.A.; Barczak, E.J.; Bossert, R.C.; Brandt, J.S.; Smith, G.A.

    1989-03-01

    Superconducting Super Collider dipole coils must be produced to high precision to ensure uniform prestress and even conductor distribution within the collared coil assembly. Tooling is being prepared at Fermilab for the production of high precision 1M and 16.6M SSC dipole coils suitable for mass production. The design and construction methods builds on the Tevatron tooling and production experience. Details of the design and construction methods and measured coil uniformity of 1M coils will be presented. 4 refs., 10 figs

  5. Tight aspect ratio tokamak power reactor with superconducting TF coils

    International Nuclear Information System (INIS)

    Nishio, S.; Tobita, K.; Konishi, S.; Ando, T.; Hiroki, S.; Kuroda, T.; Yamauchi, M.; Azumi, M.; Nagata, M.

    2003-01-01

    Tight aspect ratio tokamak power reactor with super-conducting toroidal field (TF) coils has been proposed. A center solenoid coil system and an inboard blanket were discarded. The key point was how to find the engineering design solution of the TF coil system with the high field and high current density. The coil system with the center post radius of less than 1 m can generate the maximum field of ∼ 20 T. This coil system causes a compact reactor concept, where the plasma major and minor radii of 3.75 m and 1.9 m, respectively and the fusion power of 1.8 GW. (author)

  6. Instrumentation and test of the Swiss LCT-coil

    International Nuclear Information System (INIS)

    Zichy, J.A.; Horvath, I.; Jakob, B.; Marinucci, C.; Vecsey, G.; Weymuth, P.; Zellweger, J.

    1985-01-01

    Just before Christmas 1983 the fabrication of the Swiss LCT-coil was finished. Tests at ambient temperature were performed on the factory site and after delivery in Oak Ridge. To avoid an undesirable delay of the rescheduled Partial-Array Test it was agreed to install the coil without its superconducting bus. In July 1984 the Swiss LCT-coil was successfully cooled down to LHe temperature together with the other two fully installed coils. Besides the cooling system, the instrumentation, measured parameters of the coil and some preliminary results obtained during the ongoing Partial-Array Test are presented

  7. Magnetic Field Alignment of PS-P4VP: a Non-Liquid Crystalline Coil-Coil Block Copolymer

    Science.gov (United States)

    Rokhlenko, Yekaterina; Zhang, Kai; Larson, Steven; Gopalan, Padma; O'Hern, Corey; Osuji, Chinedum

    2015-03-01

    Magnetic fields provide the ability to control alignment of self-assembled soft materials such as block copolymers. Most prior work in this area has relied on the presence of ordered assemblies of anisotropic liquid crystalline species to ensure sufficient magnetic anisotropy to drive alignment. Recent experiments with poly(styrene-b-4-vinylpyridine), a non-liquid crystalline BCP, however, show field-induced alignment of a lamellar microstructure during cooling across the order-disorder transition. Using in situ x-ray scattering, we examine the roles of field strength and cooling rate on the alignment response of this low MW coil-coil BCP. Alignment is first observed at field strengths as low as 1 Tesla and improves markedly with both increasing field strength and slower cooling. We present a geometric argument to illustrate the origin of a finite, non-trivial magnetic susceptibility anisotropy for highly stretched surface-tethered polymer chains and corroborate this using coarse-grained molecular dynamics simulations. We rationalize the magnetic field response of the system in terms of the mobility afforded by the absence of entanglements, the intrinsic anisotropy resulting from the stretched polymer chains and sterically constrained conjugated rings, and the large grain size in these low molecular weight materials.

  8. Coil supporting device for a nuclear fusion device

    International Nuclear Information System (INIS)

    Kuno, Kazuo.

    1976-01-01

    Object: To reduce a thermal stress of a coil such as a magnetic limiter to minimize stress acting on a protective tube of the coil. Structure: A coil within a protective tube has its outer periphery surrounded and supported by a heat-resisting material such as ceramic at more than two positions suitably spaced lengthwise of a coil conductor, and heat insulating members are interposed between both sides of the coil and the protective tube so that it may be retained with respect to the width of the coil. Further, a heat-resisting resilient member is inserted in a clearance between an outer circumference and an inner circumference of the coil to allow a radial displacement of the coil. As a result, elongation of the coil due to thermal expansion may be escaped at the aforesaid two supports to reduce thermal stress of the coil and protective tube to support the coil within the protective tube in positively heat-resisting and insulating manner. (Kamimura, M.)

  9. Stress relaxation in SSC 50mm dipole coils

    International Nuclear Information System (INIS)

    Rogers, D.; Markley, F.

    1992-04-01

    We are measuring the stress relaxation of SSC 50mm outer coils with the goal of predicting how much of the coil prestress will be lost while the coils are warehoused between manufacture and cooldown. We manufacture 3 inch (76.2mm) long segments of coil with the same materials and techniques that have been used for prototype coils. We are running four simultaneous tests in an attempt to separate the contributions of the different coil materials. Test one is a completely insulated coil section where the insulation is the all polyamide system being tested at Brookhaven; test two is a wire stack insulated only with the normal Kapton overwrap; test three is a stack of bare cable; and test four is a completely insulated normal coil section. All, except for the bare cable, include the ground insulation. The insulated coil sections are carefully dried before loading and testing in order to eliminate stress changes due to varying moisture content. The temperature dependence of the stress relaxation is being studied separately. Three companion papers presented at this conference will be: (1) ''Temperature dependence of the viscoelastic properties of SSC coil insulation'' (2) ''Measurement of the elastic modulus of Kapton perpendicular to the plane of the film at room and cryogenic temperatures'' (3) ''Theoretical methods for creep and stress relaxation studies of SSC coil.''

  10. Eccentric figure-eight coils for transcranial magnetic stimulation.

    Science.gov (United States)

    Sekino, Masaki; Ohsaki, Hiroyuki; Takiyama, Yoshihiro; Yamamoto, Keita; Matsuzaki, Taiga; Yasumuro, Yoshihiro; Nishikawa, Atsushi; Maruo, Tomoyuki; Hosomi, Koichi; Saitoh, Youichi

    2015-01-01

    Previously we proposed an eccentric figure-eight coil that can cause threshold stimulation in the brain at lower driving currents. In this study, we performed numerical simulations and magnetic stimulations to healthy subjects for evaluating the advantages of the eccentric coil. The simulations were performed using a simplified spherical brain model and a realistic human brain model. We found that the eccentric coil required a driving current intensity of approximately 18% less than that required by the concentric coil to cause comparable eddy current densities within the brain. The eddy current localization of the eccentric coil was slightly higher than that of the concentric coil. A prototype eccentric coil was designed and fabricated. Instead of winding a wire around a bobbin, we cut eccentric-spiral slits on the insulator cases, and a wire was woven through the slits. The coils were used to deliver magnetic stimulation to healthy subjects; among our results, we found that the current slew rate corresponding to motor threshold values for the concentric and eccentric coils were 86 and 78 A/µs, respectively. The results indicate that the eccentric coil consistently requires a lower driving current to reach the motor threshold than the concentric coil. Future development of compact magnetic stimulators will enable the treatment of some intractable neurological diseases at home. © 2014 Wiley Periodicals, Inc.

  11. Coils in a fusion device and its fabrication method

    International Nuclear Information System (INIS)

    Maeda, Hideto; Moritani, Einoshin.

    1975-01-01

    Object: To provide a coil for nuclear fusion equipment, which coil has superior rigidity and strength and is separable into two sections and used for removing impurity ions from high temperature plasma such as heavy hydrogen and tritium. Structure: The coil according to the invention is manufactured by (1) a step of insulating horseshoe-shaped conductors one from another and bundling them into coil halves. (2) a step of assembling a flange on a coil case accommodating each coil half and hermetically welding a lid to each end of the coil half, (3) a step of evacuating the interior of each coil case, (4) a step of pouring a thermosetting resin into each evacuated coil case and hardening the resin, (5) a step of connecting the two coil halves with their ends not covered with resin held in abutting relation to each other, (6) a step of coupling coil case joint pieces to the joined portions and covering the joint pieces with a seal box and hermetically welding the box to the joint pieces, and (7) a step of pouring a thermosetting resin into each evacuated joint portion and hardening the resin. (Kamimura, M.)

  12. Performance of the Conduction-Cooled LDX Levitation Coil

    Science.gov (United States)

    Michael, P. C.; Schultz, J. H.; Smith, B. A.; Titus, P. H.; Radovinsky, A.; Zhukovsky, A.; Hwang, K. P.; Naumovich, G. J.; Camille, R. J.

    2004-06-01

    The Levitated Dipole Experiment (LDX) was developed to study plasma confinement in a dipole magnetic field. Plasma is confined in the magnetic field of a 680-kg Nb3Sn Floating Coil (F-coil) that is electromagnetically supported at the center of a 5-m diameter by 3-m tall vacuum chamber. The Levitation Coil (L-coil) is a 2800-turn, double pancake winding that supports the weight of the F-coil and controls its vertical position within the vacuum chamber. The use of high-temperature superconductor (HTS) Bi-2223 for the L-coil minimizes the electrical and cooling power needed for levitation. The L-coil winding pack and support plate are suspended within the L-coil cryostat and cooled by conduction to a single-stage cryocooler rated for 25-W heat load at approximately 20 K. The coil current leads consist of conduction-cooled copper running from room temperature to 80 K and a pair of commercially-available, 150-A HTS leads. An automatically filled liquid-nitrogen reservoir provides cooling for the coil's radiation shield and for the leads' 80-K heat stations. This paper discusses the L-coil system design and its observed cryogenic performance.

  13. Coil irrigation in sugar cane (Saccharum officinarum

    Directory of Open Access Journals (Sweden)

    Jesús Sánchez Gutiérrez

    2016-01-01

    Full Text Available This study was made at the Basic Seed Bank of the Local Sugar Cane Research Station for the Mideastern Cuba, based in Camaguey, on brown carbonate soil, between 2013 and 12014. Coil irrigation was applied to meet the water requirements for the crop, according to the edafoclimatic conditions and the different phenological phases it has. The Savo method was used to determine useful rain water. Adjustment and complementation of the irrigation program was based on indicators that characterize the exploitation scheme. The machine´s working parameters were determined to meet the water needs, and increase crop´s overall yields. The evaluations and results achieved have contributed to new proposals for management and operation of coil irrigation, and they are important to increase its efficiency.

  14. Superconductors for W VII-X coils

    International Nuclear Information System (INIS)

    Maurer, W.

    1987-01-01

    Superconductor concepts are discussed with respect to operational current, cooling and bending behavior, and ac losses. The encouraging results for NbTi superconducting technology are recalled. It is argued that the WVII-X stellarator modular superconducting coils can be built just as the modular Cu coils for WVII-AS. Special attention must be paid to the dB/dt allowed for the conductor. Shape and price depend on the means used to avoid ac losses. Formula to elucidate the main physical parameters influencing ac loss behavior of superconductors are given. Configurations investigated with respect to plasma behavior are compared. Masses to be cooled were estimated for two configurations. The estimated cooling power is of the order of 3kW

  15. Power conditioner for a coil-gun

    International Nuclear Information System (INIS)

    Zabar, Z.; Joshi, P.N.

    1987-01-01

    This paper describes a power conditioning scheme for introducing currents sequentially into a linear array of coils which form the barrel of a coil-gun. The projectile, a conducting cylindrical sleeve, is driven by the force exerted on it by a traveling magnetic wave-packet created by the barrel currents. Since the rate of energy transfer is proportional to the projectile velocity, it was convenient to divide the barrel into three separate sections. These correspond to the low, medium and high velocity parts of the projectile motion. Each section is excited by a different method, chosen to satisfy the need for most efficient usage of energy stored in the power supply capacitors. Experiments are described with a breadboard model that test the feasibility of the medium-velocity power conditioning scheme

  16. Design of a dynamic transcranial magnetic stimulation coil system.

    Science.gov (United States)

    Ge, Sheng; Jiang, Ruoli; Wang, Ruimin; Chen, Ji

    2014-08-01

    To study the brain activity at the whole-head range, transcranial magnetic stimulation (TMS) researchers need to investigate brain activity over the whole head at multiple locations. In the past, this has been accomplished with multiple single TMS coils that achieve quasi whole-head array stimulation. However, these designs have low resolution and are difficult to position and control over the skull. In this study, we propose a new dynamic whole-head TMS mesh coil system. This system was constructed using several sagittal and coronal directional wires. Using both simulation and real experimental data, we show that by varying the current direction and strength of each wire, this new coil system can form both circular coils or figure-eight coils that have the same features as traditional TMS coils. Further, our new system is superior to current coil systems because stimulation parameters such as size, type, location, and timing of stimulation can be dynamically controlled within a single experiment.

  17. Globally optimal superconducting magnets part II: symmetric MSE coil arrangement.

    Science.gov (United States)

    Tieng, Quang M; Vegh, Viktor; Brereton, Ian M

    2009-01-01

    A globally optimal superconducting magnet coil design procedure based on the Minimum Stored Energy (MSE) current density map is outlined. The method has the ability to arrange coils in a manner that generates a strong and homogeneous axial magnetic field over a predefined region, and ensures the stray field external to the assembly and peak magnetic field at the wires are in acceptable ranges. The outlined strategy of allocating coils within a given domain suggests that coils should be placed around the perimeter of the domain with adjacent coils possessing alternating winding directions for optimum performance. The underlying current density maps from which the coils themselves are derived are unique, and optimized to possess minimal stored energy. Therefore, the method produces magnet designs with the lowest possible overall stored energy. Optimal coil layouts are provided for unshielded and shielded short bore symmetric superconducting magnets.

  18. Eddy current testing probe with dual half-cylindrical coils

    Science.gov (United States)

    Bae, Byung-Hoon; Choi, Jung-Mi; Kim, Soo-Yong

    2000-02-01

    We have developed a new eddy current probe composed of a dual half-cylindrical (2HC) coil as an exciting coil and a sensing coil that is placed in the small gap of the 2HC coil. The 2HC coil induces a linear eddy current on the narrow region within the target medium. The magnitude of eddy current has a maximum peak with the narrow width, underneath the center of the exciting 2HC coil. Because of the linear eddy current, the probe can be used to detect not only the existence of a crack but also its direction in conducting materials. Using specimen with a machined crack, and varying the exciting frequency from 0.5 to 100 kHz, we investigated the relationships between the direction of crack and the output voltage of the sensing coil.

  19. New technique for wiring SSC superconducting sextupole corrector coils

    International Nuclear Information System (INIS)

    Leon, B.

    1985-01-01

    There exists in the electronics industry, a technology for the manufacture of printed circuit (PC) boards which is directly transferable into the creation of highly controlled coils, such as the SSC sextupole superconducting corrector coils. This technology, which uses a process of laying down insulated wire in highly controlled patterns has heretofore been confined exclusively to the manufacture of high density printed circuit (PC) boards, possibly due to an ignorance of its utility in the field of precision winding of coils. This ability to fix wires in a well defined location can be used to produce precision wound coils in a very cost-effective manner. These coils may be superior in quality to conventionally made coils. Before describing what can be created with this technology, it is necessary to take a look at this coil winding process, the MULTIWIRE process, and the industry which has utilized this technology

  20. A new technique for wiring SSC superconducting sextupole corrector coils

    International Nuclear Information System (INIS)

    Leon, B.

    1985-01-01

    There exists in the electronics industry, a technology for the manufacture of printed circuit (PC) boards which is directly transferable into the creation of highly controlled coils, such as the SSC sextupole superconducting corrector coils. This technology, which uses a process of laying down insulated wire in highly controlled patterns, has heretofore been confined excusively to the manufacture of high density printed circuit (PC) boards, possibly due to an ignorance of its utility in the field of precision winding of coils. This ability to fix wires in a well defined location can be used to produce precision wound coils in a very cost-effective manner. These coils may be superior in quality to conventionally made coils. Before describing what can be created with this technology, it is necessary to take a look at this coil winding process, the MULTIWIRE process, and the industry which has utilized this technology

  1. Manufacture and mechanical test of a TORE SUPRA model coil

    International Nuclear Information System (INIS)

    Aymar, R.; Claudet, G.; Disdier, F.; Hamelin, J.; Libeyre, P.; Mayaux, G.; Meuris, C.; Parain, J.; Torossian, A.

    1980-09-01

    Inside the qualifying test programme, supporting the Tore Supra Design, a reduced scale model of a Bsub(T) coil was fabricated by a large industrial firm. This model coil is provided with the same features as those retained for the complete magnet. Tests of this model coil have been carried out in such a way that most of stresses which will arise in Tore Supra windings are simulated; simultaneously its cryogenic supply is fully representative of the system retained for the complete machine. Operation of the model coil has been found highly stable; under the conditions of applied field and forces a coil transition could be triggered, by an electrical heater located inside the coil, only when the temperature of the superfluid helium bath was close to Tsub(lambda). Thus, design and manufacturing techniques have been qualified satisfactorily to proceed to the next step: fabrication of the superconducting Bsub(T) coils of Tore Supra

  2. Mechanical properties of ISABELLE superconducting coils

    International Nuclear Information System (INIS)

    Thompson, P.; Bertsche, A.; Fuhrmann, J.; Greene, A.; Grove, E.; Repeta, L.; Short, F.; Tannenbaum, M.; Wanderer, P.

    1981-01-01

    As a part of the manufacturing processes, several mechanical measurements are made on ISABELLE dipoles. These are done both to control the process and to provide information for the evaluation of the behavior of the completed magnets. This paper discusses the Young's Modulus (E = 1-3 x 10 6 psi), the thermal contraction of the coil assembly (ΔL/L = 290 +- 17 x 10 -5 at 77 0 K), and the loss of applied prestress with time

  3. Voice coil based scanning probe microscopy

    Czech Academy of Sciences Publication Activity Database

    Klapetek, P.; Valtr, M.; Duchoň, V.; Sobota, Jaroslav

    2012-01-01

    Roč. 7, č. 6 (2012), 332:1-7 ISSN 1931-7573 R&D Projects: GA MPO FR-TI1/241; GA AV ČR KAN311610701; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : SPM * Voice coil * Interferometry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.524, year: 2012

  4. Plan for the large coil program

    International Nuclear Information System (INIS)

    Haubenreich, P.N.; Anderson, W.C.; Luton, J.N.; Thompson, P.B.

    1977-02-01

    This document has been prepared by the Large Coil Program (LCP) to make generally available the information that has been generated up to this point and to indicate the direction of future work. A summary of objectives, general strategy, and implementation of the LCP is given. Expanded descriptions are given of program content, technical requirements, selection of testing arrangements, tentative schedule and method of preliminary cost estimation

  5. LLNL high-field coil program

    International Nuclear Information System (INIS)

    Miller, J.R.

    1986-01-01

    An overview is presented of the LLNL High-Field Superconducting Magnet Development Program wherein the technology is being developed for producing fields in the range of 15 T and higher for both mirror and tokamak applications. Applications requiring less field will also benefit from this program. In addition, recent results on the thermomechanical performance of cable-in-conduit conductor systems are presented and their importance to high-field coil design discussed

  6. Endosphenoidal coil for intraoperative magnetic resonance imaging of the pituitary gland during transsphenoidal surgery.

    Science.gov (United States)

    Chittiboina, Prashant; Talagala, S Lalith; Merkle, Hellmut; Sarlls, Joelle E; Montgomery, Blake K; Piazza, Martin G; Scott, Gretchen; Ray-Chaudhury, Abhik; Lonser, Russell R; Oldfield, Edward H; Koretsky, Alan P; Butman, John A

    2016-12-01

    OBJECTIVE Pituitary MR imaging fails to detect over 50% of microadenomas in Cushing's disease and nearly 80% of cases of dural microinvasion. Surface coils can generate exceptionally high-resolution images of the immediately adjacent tissues. To improve imaging of the pituitary gland, a receive-only surface coil that can be placed within the sphenoid sinus (the endosphenoidal coil [ESC]) during transsphenoidal surgery (TSS) was developed and assessed. METHODS Five cadaver heads were used for preclinical testing of the ESC. The ESC (a double-turn, 12-mm-diameter surface coil made from 1-mm-diameter copper wire) was developed to obtain images in a 1.5-T MR scanner. The ESC was placed (via a standard sublabial TSS approach) on the anterior sella face. Clinical MR scans were obtained using the 8-channel head coil and ESC as the receiver coils. Using the ESC, ultra-high-resolution, 3D, balanced fast field echo (BFFE) and T1-weighted imaging were performed at resolutions of 0.25 × 0.25 × 0.50 mm 3 and 0.15 × 0.15 × 0.30 mm 3 , respectively. RESULTS Region-of-interest analysis indicated a 10-fold increase in the signal-to-noise ratio (SNR) of the pituitary when using the ESC compared with the 8-channel head coil. ESC-related improvements (p anterior pituitary gland surface. High-resolution BFFE MR imaging obtained using ESC revealed a number of anatomical features critical to pituitary surgery that were not visible on 8-channel MR imaging, including the pituitary capsule, the intercavernous sinus, and microcalcifications in the pars intermedia. These ESC imaging findings were confirmed by the pathological correlation with whole-mount pituitary sections. CONCLUSIONS ESC can significantly improve SNR in the sellar region intraoperatively using current 1.5-T MR imaging platforms. Improvement in SNR can provide images of the sella and surrounding structures with unprecedented resolution. Clinical use of this ESC may allow for MR imaging detection of previously occult

  7. Endosphenoidal coil for intraoperative magnetic resonance imaging of the pituitary gland during transsphenoidal surgery

    Science.gov (United States)

    Chittiboina, Prashant; Talagala, S. Lalith; Merkle, Hellmut; Sarlls, Joelle E.; Montgomery, Blake K.; Piazza, Martin G.; Scott, Gretchen; Ray-Chaudhury, Abhik; Lonser, Russell R.; Oldfield, Edward H.; Koretsky, Alan P.; Butman, John A.

    2016-01-01

    OBJECTIVE Pituitary MR imaging fails to detect over 50% of microadenomas in Cushing’s disease and nearly 80% of cases of dural microinvasion. Surface coils can generate exceptionally high-resolution images of the immediately adjacent tissues. To improve imaging of the pituitary gland, a receive-only surface coil that can be placed within the sphenoid sinus (the endosphenoidal coil [ESC]) during transsphenoidal surgery (TSS) was developed and assessed. METHODS Five cadaver heads were used for preclinical testing of the ESC. The ESC (a double-turn, 12-mm-diameter surface coil made from 1-mm-diameter copper wire) was developed to obtain images in a 1.5-T MR scanner. The ESC was placed (via a standard sublabial TSS approach) on the anterior sella face. Clinical MR scans were obtained using the 8-channel head coil and ESC as the receiver coils. Using the ESC, ultra–high-resolution, 3D, balanced fast field echo (BFFE) and T1-weighted imaging were performed at resolutions of 0.25 × 0.25 × 0.50 mm3 and 0.15 × 0.15 × 0.30 mm3, respectively. RESULTS Region-of-interest analysis indicated a 10-fold increase in the signal-to-noise ratio (SNR) of the pituitary when using the ESC compared with the 8-channel head coil. ESC-related improvements (p pituitary gland surface. High-resolution BFFE MR imaging obtained using ESC revealed a number of anatomical features critical to pituitary surgery that were not visible on 8-channel MR imaging, including the pituitary capsule, the intercavernous sinus, and microcalcifications in the pars intermedia. These ESC imaging findings were confirmed by the pathological correlation with whole-mount pituitary sections. CONCLUSIONS ESC can significantly improve SNR in the sellar region intraoperatively using current 1.5-T MR imaging platforms. Improvement in SNR can provide images of the sella and surrounding structures with unprecedented resolution. Clinical use of this ESC may allow for MR imaging detection of previously occult pituitary

  8. Electron Beam Curing of Coil Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Morganstern, K. H. [Radiation Dynamics, Inc., Westbury, NY (United States)

    1969-12-15

    The application of electron accelerators for the rapid curing of coatings on coil processing of steel and aluminium appears to have many practical and economic advantages. This paper discusses this particular application, but in the general framework of electron beam application by industry. Although industry has investigated radiation application for two decades, there have been few applications to date. The reasons for this are discussed as well as the shift in attitude now taking place, indicating a more ready acceptance of radiation processing by industry. This shift is apparent particularly in the coatings field, where the benefits of radiation processing are quite evident. In order to pinpoint these benefits a specific coatings application - coil coating - has been chosen. A typical conventional coil coating line is discussed and compared to a line employing a radiation source. Specific engineering information on the types of electron accelerators suitable for this application; the relative economics of radiation vs. heat curing; and a number of other peripheral advantages of radiation are discussed. (author)

  9. Thermal analysis of track based coils

    Energy Technology Data Exchange (ETDEWEB)

    Davey, K [American MAGLEV, Inc., Edgewater, FL (United States); Zowarka, R [CEM, Austin, TX (United States)

    1996-12-31

    This document examines the temperature rise of coils embedded in a concrete matrix. The ultimate goal is to predict the steady state temperature of the coils subject to a repeated passage of vehicles at a regular interval. The primary concern is in maintaining a maximum temperature which is less than that which would compromise the integrity of the insulation used on the wires. Three techniques are used to examine the problem. First, an analytical approach is used to determine not only the immediate temperature rise of the wire material itself, but also a consevative estimate of the steady state temperature expected. Second, the equations are examined for a one dimensional transient profile of the temperature with time. Finally, a two dimensional steady state boundary element solution is employed to estimate the steady state temperature profile both within the coils and within the rail. In this two dimensional boundary element assessment, an iterative approach is employed to accurately model the heat transfer coefficient h which ultimately defines the steady state temperature. (orig.)

  10. Numerical dosimetry of transcranial magnetic stimulation coils

    Science.gov (United States)

    Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique capable of stimulating neurons by means of electromagnetic induction. TMS can be used to map brain function and shows promise for the diagnosis and treatment of neurological and psychiatric disorders. Calculation of fields induced in the brain are necessary to accurately identify stimulated neural tissue during TMS. This allows the development of novel TMS coil designs capable of stimulating deeper brain regions and increasing the localization of stimulation that can be achieved. We have performed numerical calculations of magnetic and electric field with high-resolution anatomically realistic human head models to find these stimulated brain regions for a variety of proposed TMS coil designs. The realistic head models contain heterogeneous tissue structures and electrical conductivities, yielding superior results to those obtained from the simplified homogeneous head models that are commonly employed. The attenuation of electric field as a function of depth in the brain and the localization of stimulating field have been methodically investigated. In addition to providing a quantitative comparison of different TMS coil designs the variation of induced field between subjects has been investigated. We also show the differences in induced fields between adult, adolescent and child head models to preemptively identify potential safety issues in the application of pediatric TMS.

  11. Transcatheter coil embolisation of pulmonary arteriovenous malformations

    International Nuclear Information System (INIS)

    Wingen, M.; Guenther, R.W.

    2001-01-01

    Evaluation of technical success, complications and long-term results of transcatheter coil embolisation in pulmonary arteriovenous malformations (pAVMs). Material and Methods: Transcatheter embolisations of 46 pAVMs in 14 patients were analysed retrospectively, and, 5 years after treatment, the patients were interviewed by telefone concerning persistent symptoms and complications. Main symptoms before embolisation were dyspnoe (86%), hypoxaemia (100%), cerebral ischemia (21%), and hemoptysis (14%); 11 patients (79%) suffered from hereditary hemorrhagic telangiectasia. Results: Embolisation with an average of 3,9 coils (min. 1, max. 19 coils) per pAVM yielded technical success in all cases. Only two minor complications, transitory pleuritis and a small lung infarction were observed. On follow up examination after 5 years either no residual complaints or substantial improvement of dyspnoe were reported; no patient suffered from neurologic or hemorrhagic complications after the embolisation. Conclusion: Transcatheter embolisation is a safe and minimally invasive therapy for pAVMs and has rightfully replaced surgical resection as the therapy of choice. (orig.) [de

  12. Single coil bistable, bidirectional micromechanical actuator

    Science.gov (United States)

    Tabat, Ned; Guckel, Henry

    1998-09-15

    Micromechanical actuators capable of bidirectional and bistable operation can be formed on substrates using lithographic processing techniques. Bistable operation of the microactuator is obtained using a single coil and a magnetic core with a gap. A plunger having two magnetic heads is supported for back and forth linear movement with respect to the gap in the magnetic core, and is spring biased to a neutral position in which the two heads are on each side of the gap in the core. The single electrical coil is coupled to the core and is provided with electrical current to attract one of the heads toward the core by reluctance action to drive the plunger to a limit of travel in one direction. The current is then cut off and the plunger returns by spring action toward the gap, whereafter the current is reapplied to the coil to attract the other head of the plunger by reluctance action to drive the plunger to its other limit of travel. This process can be repeated at a time when switching of the actuator is required.

  13. Quench simulation of SMES consisting of some superconducting coils

    International Nuclear Information System (INIS)

    Noguchi, S.; Oga, Y.; Igarashi, H.

    2011-01-01

    A chain of quenches may be caused by a quench of one element coil when SMES is consists of many element coils. To avoid the chain of quenches, the energy stored in element coil has to be quickly discharged. The cause of the chain of the quenches is the short time constant of the decreasing current of the quenched coil. In recent years, many HTS superconducting magnetic energy storage (HTS-SMES) systems are investigated and designed. They usually consist of some superconducting element coils due to storing excessively high energy. If one of them was quenched, the storage energy of the superconducting element coil quenched has to be immediately dispersed to protect the HTS-SMES system. As the result, the current of the other element coils, which do not reach to quench, increases since the magnetic coupling between the quenched element coil and the others are excessively strong. The increase of the current may cause the quench of the other element coils. If the energy dispersion of the element coil quenched was failed, the other superconducting element coil would be quenched in series. Therefore, it is necessary to investigate the behavior of the HTS-SMES after quenching one or more element coils. To protect a chain of quenches, it is also important to investigate the time constant of the coils. We have developed a simulation code to investigate the behavior of the HTS-SMES. By the quench simulation, it is indicated that a chain of quenches is caused by a quench of one element coil.

  14. Design and testing of a coil-unit barrel for helical coil electromagnetic launcher

    Science.gov (United States)

    Yang, Dong; Liu, Zhenxiang; Shu, Ting; Yang, Lijia; Ouyang, Jianming

    2018-01-01

    A coil-unit barrel for a helical coil electromagnetic launcher is described. It provides better features of high structural strength and flexible adjustability. It is convenient to replace the damaged coil units and easy to adjust the number of turns in the stator coils due to the modular design. In our experiments, the highest velocity measured for a 4.5-kg projectile is 47.3 m/s and the mechanical reinforcement of the launcher could bear 35 kA peak current. The relationship between the energy conversion efficiency and the inductance gradient of the launcher is also studied. In the region of low inductance gradient, the efficiency is positively correlated with the inductance gradient. However, in the region of high inductance gradient, the inter-turn arc erosion becomes a major problem of limiting the efficiency and velocity of the launcher. This modular barrel allows further studies in the inter-turn arc and the variable inductance gradient helical coil launcher.

  15. Mechanical test of the model coil wound with large conductor

    International Nuclear Information System (INIS)

    Hiue, Hisaaki; Sugimoto, Makoto; Nakajima, Hideo; Yasukawa, Yukio; Yoshida, Kiyoshi; Hasegawa, Mitsuru; Ito, Ikuo; Konno, Masayuki.

    1992-09-01

    The high rigidity and strength of the winding pack are required to realize the large superconducting magnet for the fusion reactor. This paper describes mechanical tests concerning the rigidity of the winding pack. Samples were prepared to evaluate the adhesive strength between conductors and insulators. Epoxy and Bismaleimide-Triazine resin (BT resin) were used as the conductor insulator. The stainless steel (SS) 304 bars, whose surface was treated mechanically and chemically, was applied to the modeled conductor. The model coil was would with the model conductors covered with the insulator by grand insulator. A winding model combining 3 x 3 conductors was produced for measuring shearing rigidity. The sample was loaded with pure shearing force at the LN 2 temperature. The bar winding sample, by 8 x 6 conductors, was measured the bending rigidity. These three point bending tests were carried out at room temperature. The pancake winding sample was loaded with compressive forces to measure compressive rigidity of winding. (author)

  16. Ballistocardiogram of avian eggs determined by an electromagnetic induction coil.

    Science.gov (United States)

    Ono, H; Akiyama, R; Sakamoto, Y; Pearson, J T; Tazawa, H

    1997-07-01

    As an avian embryo grows within an eggshell, the whole egg is moved by embryonic activity and also by the embryonic heartbeat. A technical interest in detecting minute biological movements has prompted the development of techniques and systems to measure the cardiogenic ballistic movement of the egg or ballistocardiogram (BCG). In this context, there is interest in using an electromagnetic induction coil (solenoid) as another simple sensor to measure the BCG and examining its possibility for BCG measurement. A small permanent magnet is attached tightly to the surface of an incubated egg, and then the egg with the magnet is placed in a solenoid. Preliminary model analysis is made to design a setup of the egg, magnet and solenoid coupling system. Then, simultaneous measurement with a laser displacement measuring system, developed previously, is made for chicken eggs, indicating that the solenoid detects the minute cardiogenic ballistic movements and that the BCG determined is a measure of the velocity of egg movements.

  17. Quench detection system of the EURATOM coil for the Large Coil Task

    International Nuclear Information System (INIS)

    Noether, G.; Gauss, S.; Maurer, W.; Siewerdt, L.; Ulbricht, A.; Wuechner, F.

    1989-01-01

    A special quench detection system has been developed for the EURATOM Large Coil Task (LCT) coil. The system is based on a bridge circuit which uses a special 'two in hand' winding technique for the pancakes of the EURATOM LCT coil. The electronic circuit was designed in a fail safe way to prevent failure of the quench detector due to failure of one of its components. A method for quick balancing of the quench detection system in a large toroidal magnet system was applied. The quench detection system worked very reliably during the experimental phase of the LCT and was within the quench detection level setting of 50 mV, i.e. the system was not sensitive to poloidal field transients at or below this level. Non-electrical methods for quench detection were also investigated. (author)

  18. Design of Electromagnetic Moving-coil type Voice Coil Motor for Scanning mirror of Barcode reader

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Bu Hyun; Lee, Jeong Woo; Shim, Hyun Ho; Park, Sang Goo [Hanbat National Univ., Daejeon (Korea, Republic of); Lee, Seung Yop [Sogang Univ., Seoul (Korea, Republic of)

    2016-01-15

    A voice coil actuator with moving coil type for scanning mirror system of barcode reader has been developed. The actuator has a simple structure including a magnet, a coil and a pin. The performance of the actuator is analyzed by a linearized theoretical model. And the dynamic performance of the proposed actuator is predicted through motor constant and restoring constant obtained by finite element simulations. The theoretical model was verified by the prototype which has 64 Hz resonance frequency and 60 deg reflecting angle. We also discovered that that 3 V input can make the actuator rotate over 61.8 deg reflecting angle at 50 Hz resonance frequency. The proposed actuator can simplify its driving configuration because of its implementation of open-loop control.

  19. First full-size ATLAS barrel toroid coil successfully tested up to 22 kA at 4 T

    CERN Document Server

    Dudarev, A; Benoit, P; Berriaud, C P; Broggi, F; Deront, L; Foussat, A; Junker, S; ten Kate, H H J; Kopeykin, N; Olesen, G; Olyunin, A; Pengo, R; Rabbers, J J; Ravat, S; Rey, J M; Sbrissa, E; Shugaev, I; Stepanov, V; Védrine, P; Volpini, Giovanni

    2005-01-01

    The Superconducting Barrel Toroid is providing (together with the two End-Cap Toroids not presented here) the magnetic field for the muon detectors in the ATLAS Experiment at the LHC at CERN. The toroid with outer dimensions of 25 m length and 20 m diameter, is built up from 8 identical racetrack coils. The coils with 120 turns each are wound with an aluminum stabilized NbTi conductor and operate at 20.5 kA at 3.9 T local field in the windings and is conduction cooled at 4.8 K by circulating forced flow helium in cooling tubes attached to the cold mass. The 8 coils of 25 m * 5 m are presently under construction and the first coils have already been fully integrated and tested. Meanwhile the assembly of the toroid 100 m underground in the ATLAS cavern at CERN has started. The 8 coils are individually tested on surface before installation. In this paper the test of the first coil, unique in size and manufacturing technology, is described in detail and the results are compared to the previous experience with the...

  20. Spiral Gradient Coil Design for Use in Cylindrical MRI Systems.

    Science.gov (United States)

    Wang, Yaohui; Xin, Xuegang; Liu, Feng; Crozier, Stuart

    2018-04-01

    In magnetic resonance imaging, the stream function based method is commonly used in the design of gradient coils. However, this method can be prone to errors associated with the discretization of continuous current density and wire connections. In this paper, we propose a novel gradient coil design scheme that works directly in the wire space, avoiding the system errors that may appear in the stream function approaches. Specifically, the gradient coil pattern is described with dedicated spiral functions adjusted to allow the coil to produce the required field gradients in the imaging area, minimal stray field, and other engineering terms. The performance of a designed spiral gradient coil was compared with its stream-function counterpart. The numerical evaluation shows that when compared with the conventional solution, the inductance and resistance was reduced by 20.9 and 10.5%, respectively. The overall coil performance (evaluated by the figure of merit (FoM)) was improved up to 26.5% for the x -gradient coil design; for the z-gradient coil design, the inductance and resistance were reduced by 15.1 and 6.7% respectively, and the FoM was increased by 17.7%. In addition, by directly controlling the wire distributions, the spiral gradient coil design was much sparser than conventional coils.