SGA-WZ: A New Strapdown Airborne Gravimeter

DEFF Research Database (Denmark)

Huang, Yangming; Olesen, Arne Vestergaard; Wu, Meiping

2012-01-01

Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance......, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter...... and discussion of the airborne field test results are also given....

Time Changes of the European Gravity Field from GRACE: A Comparison with Ground Measurements from Superconducting Gravimeters and with Hydrology Model Predictions

Science.gov (United States)

Hinderer, J.; Lemoine, Frank G.; Crossley, D.; Boy, J.-P.

2004-01-01

We investigate the time-variable gravity changes in Europe retrieved from the initial GRACE monthly solutions spanning a 18 month duration from April 2002 to October 2003. Gravity anomaly maps are retrieved in Central Europe from the monthly satellite solutions we compare the fields according to various truncation levels (typically between degree 10 and 20) of the initial fields (expressed in spherical harmonics to degree 120). For these different degrees, an empirical orthogonal function (EOF) decomposition of the time-variable gravity field leads us to its main spatial and temporal characteristics. We show that the dominant signal is found to be annual with an amplitude and a phase both in agreement with predictions in Europe modeled using snow and soil-moisture variations from recent hydrology models. We compare these GRACE gravity field changes to surface gravity observations from 6 superconducting gravimeters of the GGP (Global Geodynamics Project) European sub-network, with a special attention to loading corrections. Initial results suggest that all 3 data sets (GRACE, hydrology and GGP) are responding to annual changes in near-surface water in Europe of a few microGal (at length scales of approx.1000 km) that show a high value in winter and a summer minimum. We also point out that the GRACE gravity field evolution seems to indicate that there is a trend in gravity between summer 2002 and summer 2003 which can be related to the 2003 heatwave in Europe and its hydrological consequences (drought). Despite the limited time span of our analysis and the uncertainties in retrieving a regional solution from the network of gravimeters, the calibration and validation aspects of the GRACE data processing based on the annual hydrology cycle in Europe are in progress.

Hydrology in Central Europe - a Comparison Between Data from the GRACE Satellite Mission and Ground Superconducting Gravimeters

Science.gov (United States)

Crossley, D.; de Linage, C.; Boy, J.-P.; Hinderer, J.

2009-04-01

The surface gravity field is subject to many influences of mass redistribution within the Earth system, operating at the microgal (10-8 m s-2) level and at timescales from minutes to years. We include deformation within the Earth (tides, polar motion), motions within the atmosphere (local, regional, and global loading; also mass attractions), the oceans (non-tidal currents), and near-surface hydrology derived from rainfall (local, regional, and global contributions). In central Europe a network of 7 superconducting gravimeters (the only instrument with the required resolution for this type of work) has been operating for many years, recording variations at the sub-microgal level. Hydrology is the largest component in the un-modelled residual signal, most of which comes from an area within a few hundred m of the instrument. We use data from 2002-2007 to construct a regionalized ground gravity data set that is analyzed by Principal Component (EOF) analysis to extract the predominantly seasonal signal common to all stations. This we compare with the GRACE-derived field using solutions from GFZ Potsdam, CSR Texas, and GRGS Toulouse. There is very good agreement on the phase of the two different types of data, but the amplitude of the ground signal is complicated by the local hydrology around several of the stations, which is both above and below the instrument. We show our most recent analysis and compare the results with the GLDAS global hydrology model from NASA.

New determinations of Q quality factors and eigenfrequencies for the whole set of singlets of the Earth's normal modes 0S 0, 0S 2, 0S 3 and 2S 1 using superconducting gravimeter data from the GGP network

Science.gov (United States)

Roult, Geneviève; Rosat, Séverine; Clévédé, Eric; Millot-Langet, Raphaële; Hinderer, Jacques

2006-01-01

We present new modal Q measurements of the 0S 0 and 0S 2 modes, and first modal frequencies and Q measurements of 2S 1 and 0S 3 modes. The high quality of the GGP (Global Geodynamics Project) superconducting gravimeters (SGs) contributes to the clear observation of seismic normal modes at frequencies lower than 1 mHz and offers a good opportunity for studying the behaviour of these modes. The interest of scientists in the gravest normal modes is due to the fact that they do contribute to a better knowledge of the density profile in the Earth, helping to constrain Earth's models. These modes have been clearly identified after some large recent events recorded with superconducting gravimeters, particularly well-suited for low-frequency investigations. The Ms = 8.1 (Mw = 8.4) Peruvian earthquake of June 2001 and the Ms = 9.0 (Mw = 9.3) Sumatra-Andaman earthquake of December 2004 provide us with individual spectra which exhibit a clear splitting of the spheroidal modes 0S 2, 0S 3 and 2S 1, and a clear identification of each of the individual singlets, with a resolution never obtained from broad-band seismometers records. The Q quality factors have been determined from the apparent decrease of the amplitude of each singlet with time, according to a well-suited technique [Roult, G., Clévédé, E., 2000. New refinements in attenuation measurements from free-oscillation and surface-wave observations. Phys. Earth Planet. Inter. 121, 1-37]. The results are compared to the theoretical frequencies and Q quality factors computed for the PREM and 1066A models, taking into account both rotation and ellipticity effects of the Earth. The two observed datasets (frequencies and Q quality factors) exhibit a splitting on the observed values different from the predicted one. That seems to point out that some parameters as density or attenuation values used in the theoretical models do not explain the observations. A new dataset of frequencies and Q quality factors of the whole set of

Linear ultrasonic motor for absolute gravimeter.

Science.gov (United States)

Jian, Yue; Yao, Zhiyuan; Silberschmidt, Vadim V

2017-05-01

Thanks to their compactness and suitability for vacuum applications, linear ultrasonic motors are considered as substitutes for classical electromagnetic motors as driving elements in absolute gravimeters. Still, their application is prevented by relatively low power output. To overcome this limitation and provide better stability, a V-type linear ultrasonic motor with a new clamping method is proposed for a gravimeter. In this paper, a mechanical model of stators with flexible clamping components is suggested, according to a design criterion for clamps of linear ultrasonic motors. After that, an effect of tangential and normal rigidity of the clamping components on mechanical output is studied. It is followed by discussion of a new clamping method with sufficient tangential rigidity and a capability to facilitate pre-load. Additionally, a prototype of the motor with the proposed clamping method was fabricated and the performance tests in vertical direction were implemented. Experimental results show that the suggested motor has structural stability and high dynamic performance, such as no-load speed of 1.4m/s and maximal thrust of 43N, meeting the requirements for absolute gravimeters. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnification of mantle resonance as a cause of tectonics

OpenAIRE

Omerbashich, M.

2006-01-01

Variance spectral analysis of superconducting gravimeter (SG) decadal data (noise inclusive) is presented suggesting that the Earth tectonogenesis is based on magnification of the mass (mainly the mantle) mechanical resonance, in addition to or instead of previously hypothesized causes. Here the use of raw (gapped and unaltered) data is regarded as the criterion for a physical result validity, so data were not altered in any way. Then analogously to the atmospheric tidal forcing of global hig...

Absolute Gravity Datum in the Age of Cold Atom Gravimeters

Science.gov (United States)

Childers, V. A.; Eckl, M. C.

2014-12-01

The international gravity datum is defined today by the International Gravity Standardization Net of 1971 (IGSN-71). The data supporting this network was measured in the 1950s and 60s using pendulum and spring-based gravimeter ties (plus some new ballistic absolute meters) to replace the prior protocol of referencing all gravity values to the earlier Potsdam value. Since this time, gravimeter technology has advanced significantly with the development and refinement of the FG-5 (the current standard of the industry) and again with the soon-to-be-available cold atom interferometric absolute gravimeters. This latest development is anticipated to provide improvement in the range of two orders of magnitude as compared to the measurement accuracy of technology utilized to develop ISGN-71. In this presentation, we will explore how the IGSN-71 might best be "modernized" given today's requirements and available instruments and resources. The National Geodetic Survey (NGS), along with other relevant US Government agencies, is concerned about establishing gravity control to establish and maintain high order geodetic networks as part of the nation's essential infrastructure. The need to modernize the nation's geodetic infrastructure was highlighted in "Precise Geodetic Infrastructure, National Requirements for a Shared Resource" National Academy of Science, 2010. The NGS mission, as dictated by Congress, is to establish and maintain the National Spatial Reference System, which includes gravity measurements. Absolute gravimeters measure the total gravity field directly and do not involve ties to other measurements. Periodic "intercomparisons" of multiple absolute gravimeters at reference gravity sites are used to constrain the behavior of the instruments to ensure that each would yield reasonably similar measurements of the same location (i.e. yield a sufficiently consistent datum when measured in disparate locales). New atomic interferometric gravimeters promise a significant

SHORT COMMUNICATION: Comparison between two mobile absolute gravimeters: optical versus atomic interferometers

Science.gov (United States)

Merlet, S.; Bodart, Q.; Malossi, N.; Landragin, A.; Pereira Dos Santos, F.; Gitlein, O.; Timmen, L.

2010-08-01

We report a comparison between two absolute gravimeters: the LNE-SYRTE cold atom gravimeter and FG5#220 of Leibniz Universität of Hannover. They rely on different principles of operation: atomic and optical interferometry. Both are movable which enabled them to participate in the last International Comparison of Absolute Gravimeters (ICAG'09) at BIPM. Immediately after, their bilateral comparison took place in the LNE watt balance laboratory and showed an agreement of (4.3 ± 6.4) µGal.

SGA-WZ: A New Strapdown Airborne Gravimeter

Directory of Open Access Journals (Sweden)

Kaidong Zhang

2012-07-01

Full Text Available Inertial navigation systems and gravimeters are now routinely used to map the regional gravitational quantities from an aircraft with mGal accuracy and a spatial resolution of a few kilometers. However, airborne gravimeter of this kind is limited by the inaccuracy of the inertial sensor performance, the integrated navigation technique and the kinematic acceleration determination. As the GPS technique developed, the vehicle acceleration determination is no longer the limiting factor in airborne gravity due to the cancellation of the common mode acceleration in differential mode. A new airborne gravimeter taking full advantage of the inertial navigation system is described with improved mechanical design, high precision time synchronization, better thermal control and optimized sensor modeling. Apart from the general usage, the Global Positioning System (GPS after differentiation is integrated to the inertial navigation system which provides not only more precise altitude information along with the navigation aiding, but also an effective way to calculate the vehicle acceleration. Design description and test results on the performance of the gyroscopes and accelerations will be emphasized. Analysis and discussion of the airborne field test results are also given.

Field Tests of a Portable MEMS Gravimeter

Directory of Open Access Journals (Sweden)

Richard P. Middlemiss

2017-11-01

Full Text Available Gravimeters are used to measure density anomalies under the ground. They are applied in many different fields from volcanology to oil and gas exploration, but present commercial systems are costly and massive. A new type of gravity sensor has been developed that utilises the same fabrication methods as those used to make mobile phone accelerometers. In this study, we describe the first results of a field-portable microelectromechanical system (MEMS gravimeter. The stability of the gravimeter is demonstrated through undertaking a multi-day measurement with a standard deviation of 5.58 × 10 − 6 ms − 2 . It is then demonstrated that a change in gravitational acceleration of 4.5 × 10 − 5 ms − 2 can be measured as the device is moved between the top and the bottom of a 20.7 m lift shaft with a signal-to-noise ratio (SNR of 14.25. Finally, the device is demonstrated to be stable in a more harsh environment: a 4.5 × 10 − 4 ms − 2 gravity variation is measured between the top and bottom of a 275-m hill with an SNR of 15.88. These initial field-tests are an important step towards a chip-sized gravity sensor.

Seasonal changes in the European gravity field from GRACE: A comparison with superconducting gravimeters and hydrology model predictions

Science.gov (United States)

Hinderer, Jacques; Andersen, Ole; Lemoine, Frank; Crossley, David; Boy, Jean-Paul

2006-01-01

This paper is devoted to the investigation of seasonal changes of the Earth's gravity field from GRACE satellites and the comparison with surface gravity measurements in Europe from the Global Geodynamics Project (GGP) sub-network, as well as with recent hydrology models for continental soil moisture and snow. We used gravity maps in Europe retrieved from the initial GRACE monthly solutions spanning a 21-month duration from April 2002 to December 2003 for various truncation levels of the initial spherical harmonic decomposition of the field. The transfer function between satellite-derived and ground gravity changes due to continental hydrology is studied and we also compute the theoretical ratio of gravity versus radial displacement (in μGal/mm) involved in the hydrological loading process. The 'mean' value (averaged in time and in space over Europe) from hydrologic forward modeling is found to be close to -1.0 μGal/mm and we show that this value can be explained by a strong low degree ( n = 5-6) peak in the hydrology amplitude spectrum. The dominant time-variable signal from GRACE is found to be annual with an amplitude and a phase both of which are in fair agreement with predictions in Europe from recent hydrology models. Initial results suggest that all three data sets (GRACE, hydrology and GGP) respond to annual changes in near-surface water in Europe of a few μGal (at length scales of ˜1000 km) that show a high value in winter and a summer minimum. Despite the limited time span of our analysis and the uncertainties in separating purely local effects from regional ones in superconducting gravimeter data, the calibration and validation aspects of the GRACE data processing based on the annual hydrology cycle in Europe are in progress.

Microelectromechanical system gravimeters as a new tool for gravity imaging.

Science.gov (United States)

Middlemiss, Richard P; Bramsiepe, Steven G; Douglas, Rebecca; Hild, Stefan; Hough, James; Paul, Douglas J; Samarelli, Antonio; Rowan, Sheila; Hammond, Giles D

2018-05-28

A microelectromechanical system (MEMS) gravimeter has been manufactured with a sensitivity of 40 ppb in an integration time of 1 s. This sensor has been used to measure the Earth tides: the elastic deformation of the globe due to tidal forces. No such measurement has been demonstrated before now with a MEMS gravimeter. Since this measurement, the gravimeter has been miniaturized and tested in the field. Measurements of the free-air and Bouguer effects have been demonstrated by monitoring the change in gravitational acceleration measured while going up and down a lift shaft of 20.7 m, and up and down a local hill of 275 m. These tests demonstrate that the device has the potential to be a useful field-portable instrument. The development of an even smaller device is underway, with a total package size similar to that of a smartphone.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).

Microelectromechanical system gravimeters as a new tool for gravity imaging

Science.gov (United States)

Middlemiss, Richard P.; Bramsiepe, Steven G.; Douglas, Rebecca; Hild, Stefan; Hough, James; Paul, Douglas J.; Samarelli, Antonio; Rowan, Sheila; Hammond, Giles D.

2018-05-01

A microelectromechanical system (MEMS) gravimeter has been manufactured with a sensitivity of 40 ppb in an integration time of 1 s. This sensor has been used to measure the Earth tides: the elastic deformation of the globe due to tidal forces. No such measurement has been demonstrated before now with a MEMS gravimeter. Since this measurement, the gravimeter has been miniaturized and tested in the field. Measurements of the free-air and Bouguer effects have been demonstrated by monitoring the change in gravitational acceleration measured while going up and down a lift shaft of 20.7 m, and up and down a local hill of 275 m. These tests demonstrate that the device has the potential to be a useful field-portable instrument. The development of an even smaller device is underway, with a total package size similar to that of a smartphone. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

Development of a submersible gravimeter on underwater vehicles

Science.gov (United States)

Yamada, T.; Kanazawa, T.; Fujimoto, H.; Shinohara, M.; Ishihara, T.; Araya, A.; Iizasa, K.; Tsukioka, S.

2012-12-01

Gravity is one of the powerful indices to profile underground structures. Surface ship gravimeters are popular tool for the purpose of collecting gravity values in marine region. They enable you to obtain gravity values from large area easily, while the resolutions are relatively low because of the distance between the sea surface and bottom. Otherwise, ocean bottom gravimeters are able to be observed gravity with high resolution, but they have still covered few limited sites so that they are designed to do observation in quiet only. In some cases, such as hydrothermal deposit survey, the medium performance both in resolution and size of survey area are required. This paper describes a gravimeter we have been developing for satisfying the requirements. Our target is to detect gravity anomalies less than 1 mgal by using an underwater vehicle. This setting is roughly equivalent to find a typical hydrothermal deposit with a dimension of 0.5 km x 0.5 km x 10 m and a density contrast of 1 g/cm3 when we set the sensor at 50 m high from the seafloor. There are some issues such as noise reduction, robustness and downsizing to clear the target. A gravity sensor (Micro-g LaCoste S-174) is mounted on a gimbal control unit with an inertial navigation sensor for the problems. These are stored in a sphere vessel made of titanium alloy (125 kgf in air, 32 kgf in water) and it is available in 3500 m below sea surface. Furthermore, in order to reduce high frequency noise due to mainly the vehicle motion through a low-pass filter, data are able to be stored at sampling rates of approximately 100 Hz. The logging system and control unit for communication to/from ship is stored another canister (22 kgf in air, 10 kgf in water). We made gravity measurement experiments to examine the effectiveness of the gimbal system and filtering application. The gravimeter was set on a machine simulating pitch and roll motions with a period of 16 s and an amplitude of 7.5 degrees, which is greater

The new Absolute Quantum Gravimeter (AQG): first results and perspectives

Science.gov (United States)

Bonvalot, Sylvain; Le Moigne, Nicolas; Merlet, Sebastien; Desruelle, Bruno; Lautier-Gaud, Jean; Menoret, Vincent; Vermeulen, Pierre

2016-04-01

Cold atom gravimetry represents one of the most innovative evolution in gravity instrumentation since the last 20 years. The concept of measuring the gravitational acceleration by dropping atoms and the development of the first instrumental devices during this last decade quickly revealed the promising perspectives of this new generation of gravity meters enabling accurate and absolute measurements of the Earth's gravity field for a wide range of applications (geophysics, geodesy, metrology, etc.). The Absolute Quantum Gravimeter (AQG) gravity meter, developed by MUQUANS (Talence, France - http://www.muquans.com/) with the support of RESIF, the French Seismologic and Geodetic Network (http://www.resif.fr/) belongs to this new generation of instruments. It also represents the first commercial device based on the utilization of advanced matter-wave interferometry techniques, which allow to characterize precisely the vertical acceleration experienced by a cloud of cold atoms. Recently, the first operational unit (AQG01) has been achieved as a compact transportable gravimeter with the aim of satisfying absolute gravity measurements in laboratory conditions under the following specifications: measurements the μGal level at a few Hz cycling frequency, sensitivity of 50μGal/√Hz, immunity to ground vibrations, easy and quickness of operation, automated continuous data acquisition for several months, etc. In order to evaluate the current performances of the AQG01, several experiments are carried out in collaboration between RESIF user's teams and the MUQUANS manufacturer on different reference gravity sites and laboratories in France. These measurements performed in indoor conditions including simultaneous observations with classical reference gravity instruments (corner-cube absolute gravity meters, relative superconducting meters) as well with the Cold Atom Gravity meter (CAG) developed by LNE-SYRTE, lead to a first objective characterization of the performances of

Absolute gravity measurements at three sites characterized by different environmental conditions using two portable ballistic gravimeters

Science.gov (United States)

Greco, Filippo; Biolcati, Emanuele; Pistorio, Antonio; D'Agostino, Giancarlo; Germak, Alessandro; Origlia, Claudio; Del Negro, Ciro

2015-03-01

The performances of two absolute gravimeters at three different sites in Italy between 2009 and 2011 is presented. The measurements of the gravity acceleration g were performed using the absolute gravimeters Micro-g LaCoste FG5#238 and the INRiM prototype IMGC-02, which represent the state of the art in ballistic gravimeter technology (relative uncertainty of a few parts in 109). For the comparison, the measured g values were reported at the same height by means of the vertical gravity gradient estimated at each site with relative gravimeters. The consistency and reliability of the gravity observations, as well as the performance and efficiency of the instruments, were assessed by measurements made in sites characterized by different logistics and environmental conditions. Furthermore, the various factors affecting the measurements and their uncertainty were thoroughly investigated. The measurements showed good agreement, with the minimum and maximum differences being 4.0 and 8.3 μGal. The normalized errors are very much lower than 1, ranging between 0.06 and 0.45, confirming the compatibility between the results. This excellent agreement can be attributed to several factors, including the good working order of gravimeters and the correct setup and use of the instruments in different conditions. These results can contribute to the standardization of absolute gravity surveys largely for applications in geophysics, volcanology and other branches of geosciences, allowing achieving a good trade-off between uncertainty and efficiency of gravity measurements.

First Impressions of a Scintrex CG-6 Portable Gravimeter in an Extensive Field Campaign

Science.gov (United States)

van Westrum, D.; Kanney, J.

2017-12-01

First Impressions of a Scintrex CG-6 Portable Gravimeter in an Extensive Field Campaign AGU Fall Meeting 2017 Derek van Westrum and Jeff Kanney NOAA's National Geodetic Survey conducted its third and final Geoid Slope Validation Survey (GSVS) this past summer in the rugged mountains of southern Colorado. In addition to leveling, long period GPS, and defelction of vertical observations, absolute gravity and vertical gravity gradients were measured at 235 bench marks (approximately 1.5 km spacing) along US-160 between Durango and Walsenburg, Colorado. In previous surveys (Texas-2011 and Iowa-2014), an A10 absolute gravimeter was used to measure graivty at approximately 10-15% of the bench marks. The remaining marks were determined by using LaCoste & Romberg relative gravimeters. The same relative instruments were also used to measure two-tier (linear) vertical gravity gradients at the A10 sites. In the current work - becuase of the rapidly changing terrain in the Rocky Mountains - it was decided to employ the A10 at all 235 bench marks, and acquire three-tier (quadratic) gradients at every bench mark using the new Scintrex CG-6 Autograv relative gravimeter. Using these results, we will provide a real worldsummary of the CG-6's behavior by examining noise levels, repeatability, and acquisition rates. In addition, the coincident A10 absolute data set allows us to evaluate the CG-6's accuracy, and allows us to simulate and discuss various relative gravity survey designs.

A vibration correction method for free-fall absolute gravimeters

Science.gov (United States)

Qian, J.; Wang, G.; Wu, K.; Wang, L. J.

2018-02-01

An accurate determination of gravitational acceleration, usually approximated as 9.8 m s-2, has been playing an important role in the areas of metrology, geophysics, and geodetics. Absolute gravimetry has been experiencing rapid developments in recent years. Most absolute gravimeters today employ a free-fall method to measure gravitational acceleration. Noise from ground vibration has become one of the most serious factors limiting measurement precision. Compared to vibration isolators, the vibration correction method is a simple and feasible way to reduce the influence of ground vibrations. A modified vibration correction method is proposed and demonstrated. A two-dimensional golden section search algorithm is used to search for the best parameters of the hypothetical transfer function. Experiments using a T-1 absolute gravimeter are performed. It is verified that for an identical group of drop data, the modified method proposed in this paper can achieve better correction effects with much less computation than previous methods. Compared to vibration isolators, the correction method applies to more hostile environments and even dynamic platforms, and is expected to be used in a wider range of applications.

Superconducting Gravimeters Detect Gravity Fluctuations Induced by Mw 5.7 Earthquake Along South Pacific Rise Few Hours Before the 2011 Mw 9.0 Tohoku-Oki Earthquake

Directory of Open Access Journals (Sweden)

Keliang Zhang Jin Ma

2014-01-01

Full Text Available Gravity changes sometimes appear before a big earthquake. To determine the possible sources is important for recognizing the mechanism and further geodynamic studies. During the first two hours on March 11 before the Mw 9.0 Tohoku-Oki earthquake, the non-tidal gravity time series of superconducting gravimeters worldwide showed low-frequency (< 0.10 Hz fluctuations with amplitude of ~1 to 4 × 10-8 ms-2 lasting ~10 - 20 minutes. Through comparing global seismicity with the arrival times of seismic waves, we find that the fluctuations were induced by the Mw 5.7 earthquake that occurred at 0:14:54.68 at (53.27°S, 118.18°W along the eastern South Pacific Rise. Several body waves such as P, S are clearly recorded in the station with ~400 km distance to the hypocenter. The fluctuations are in response to the waves that propagate with a velocity of about 4 km s-1. Their amplitudes are proportional to the inverse of the epicentral distances even though the fluctuations of European sites were overlapped with waves associated with a smaller, i.e., Mw 2.6, event in Europe during this period. That is, the Mw 5.7 earthquake induced remarkable gravity fluctuations over long distances at stations all over the world. As such, the foreshocks with larger magnitudes occurred before the Mw 9.0 earthquake would have more significant influence on the gravity recordings and the seismic-wave induced component should be removed during the analysis of anomalies prior to a great earthquake in future studies.

Results of the Sixth International Comparison of Absolute Gravimeters, ICAG-2001

Czech Academy of Sciences Publication Activity Database

Vitushkin, L.; Becker, M.; Jiang, Z.; Francis, O.; van Dam, T. M.; Faller, J.; Chartier, J.M.; Amalvict, M.; Bonvalot, S.; Debeglia, N.; Desogus, S.; Diament, M.; Dupont, F.; Falk, R.; Gabalda, G.; Gagnon, C. G. L.; Gattacceca, T.; Germak, A.; Hinderer, J.; Jamet, O.; Jeffries, G.; Käker, R.; Kopaev, A.; Liard, J.; Lindau, A.; Longuevergne, L.; Luck, B.; Maderal, E. N.; Mäkinen, J.; Meurers, B.; Mizushima, S.; Mrlina, Jan; Newell, D.; Origlia, C.; Pujol, E. R.; Reinhold, A.; Richard, P.; Robinson, I. A.; Ruess, D.; Thies, S.; Van Camp, M.; Van Ruymbeke, M.; de Villalta Compagni, M. F.; Williams, S.

2002-01-01

Roč. 39, č. 5 (2002), s. 407-424 ISSN 0026-1394 Institutional research plan: CEZ:AV0Z3012916 Keywords : absolute gravimeters * BIPM gravity network * measurement Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.842, year: 2002

High-precision gravity measurements using absolute and relative gravimeters at Mount Etna (Sicily, Italy

Directory of Open Access Journals (Sweden)

Ciro Del Negro

2011-12-01

Full Text Available Accurate detection of time gravity changes attributable to the dynamics of volcanoes requires high-precision gravity measurements. With the aim of improving the quality of data from the Mount Etna gravity network, we used both absolute and relative gravimeters in a hybrid method. In this report, some of the techniques for gravity surveys are reviewed, and the results related to each method are compared. We show how the total uncertainty estimated for the gravity measurements performed with this combined use of absolute and relative gravimeters is roughly comparable to that calculated when the measurements are acquired using only relative gravimeters (the traditional method. However, the data highlight how the hybrid approach improves the measurement capabilities for surveying the Mount Etna volcanic area. This approach enhances the accuracy of the data, and then of the four-dimensional surveying, which minimizes ambiguities inherent in the gravity measurements. As a case study, we refer to two gravity datasets acquired in 2005 and 2010 from the western part of the Etna volcano, which included five absolute and 13 relative stations of the Etna gravity network.

FFT swept filtering: a bias-free method for processing fringe signals in absolute gravimeters

Science.gov (United States)

Křen, Petr; Pálinkáš, Vojtech; Mašika, Pavel; Val'ko, Miloš

2018-05-01

Absolute gravimeters, based on laser interferometry, are widely used for many applications in geoscience and metrology. Although currently the most accurate FG5 and FG5X gravimeters declare standard uncertainties at the level of 2-3 μGal, their inherent systematic errors affect the gravity reference determined by international key comparisons based predominately on the use of FG5-type instruments. The measurement results for FG5-215 and FG5X-251 clearly showed that the measured g-values depend on the size of the fringe signal and that this effect might be approximated by a linear regression with a slope of up to 0.030 μGal/mV . However, these empirical results do not enable one to identify the source of the effect or to determine a reasonable reference fringe level for correcting g-values in an absolute sense. Therefore, both gravimeters were equipped with new measuring systems (according to Křen et al. in Metrologia 53:27-40, 2016. https://doi.org/10.1088/0026-1394/53/1/27 applied for FG5), running in parallel with the original systems. The new systems use an analogue-to-digital converter HS5 to digitize the fringe signal and a new method of fringe signal analysis based on FFT swept bandpass filtering. We demonstrate that the source of the fringe size effect is connected to a distortion of the fringe signal due to the electronic components used in the FG5(X) gravimeters. To obtain a bias-free g-value, the FFT swept method should be applied for the determination of zero-crossings. A comparison of g-values obtained from the new and the original systems clearly shows that the original system might be biased by approximately 3-5 μGal due to improperly distorted fringe signal processing.

Experimental assessment of the speed of light perturbation in free-fall absolute gravimeters

CERN Document Server

Baumann, H; Blas, D.; Sibiryakov, S.; Eichenberger, A.; Klingelé, E.E.

2015-01-01

Precision absolute gravity measurements are growing in importance, especially in the context of the new definition of the kilogram. For the case of free-fall absolute gravimeters with a Michelson-type interferometer tracking the position of a free falling body, one of the effects that needs to be taken into account is the speed of light perturbation due to the finite speed of propagation of light. This effect has been extensively discussed in the past, and there is at present a disagreement between different studies. In this work, we present the analysis of new data and confirm the result expected from the theoretical analysis applied nowadays in free-fall gravimeters. We also review the standard derivations of this effect (by using phase shift or Doppler effect arguments) and show their equivalence.

WPEC Subgroup Meetings. Joint SG38/SG39/SG40-CIELO meeting, 20 May 2015

International Nuclear Information System (INIS)

Brown, Dave; Palmiotti, G.; Salvatores, M.; Chadwick, M.; Mattoon, Caleb; Yokoyama, K.; Leal, L.; Diez, C.J.; Hill, I.; Ignatyuk, A.

2015-05-01

WPEC subgroup 38 (SG38) was formed to develop a new structure for storing nuclear reaction data, that is meant to eventually replace ENDF-6 as the standard way to store and share evaluations. The work of SG38 covers the following tasks: Designing flexible, general-purpose data containers; Determining a logical and easy-to-understand top-level hierarchy for storing evaluated nuclear reaction data; Creating a particle database for storing particles, masses and level schemes; Specifying the infrastructure (plotting, processing, etc.) that must accompany the new structure; Developing an Application Programming Interface or API to allow other codes to access data stored in the new structure; Specifying what tests need to be implemented for quality assurance of the new structure and associated infrastructure; Ensuring documentation and governance of the structure and associated infrastructure. The aim of WPEC subgroup 39 'Methods and approaches to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data files' is to provide criteria and practical approaches to use effectively the results of sensitivity analyses and cross section adjustments for feedback to evaluators and differential measurement experimentalists in order to improve the knowledge of neutron cross sections, uncertainties, and correlations to be used in a wide range of applications. WPEC subgroup 40-CIELO (Collaborative International Evaluated Library Organization) provides a new working paradigm to facilitate evaluated nuclear reaction data advances. It brings together experts from across the international nuclear reaction data community to identify and document discrepancies among existing evaluated data libraries, measured data, and model calculation interpretations, and aims to make progress in reconciling these discrepancies to create more accurate ENDF-formatted files. SG40-CIELO focusses on 6 important isotopes: "1H, "1"6O, "5"6Fe, "2"3"5","2"3"8U, "2"3"9Pu. This

Optimized Design of the SGA-WZ Strapdown Airborne Gravimeter Temperature Control System

Directory of Open Access Journals (Sweden)

Juliang Cao

2015-12-01

Full Text Available The temperature control system is one of the most important subsystems of the strapdown airborne gravimeter. Because the quartz flexible accelerometer based on springy support technology is the core sensor in the strapdown airborne gravimeter and the magnet steel in the electromagnetic force equilibrium circuits of the quartz flexible accelerometer is greatly affected by temperature, in order to guarantee the temperature control precision and minimize the effect of temperature on the gravimeter, the SGA-WZ temperature control system adopts a three-level control method. Based on the design experience of the SGA-WZ-01, the SGA-WZ-02 temperature control system came out with a further optimized design. In 1st level temperature control, thermoelectric cooler is used to conquer temperature change caused by hot weather. The experiments show that the optimized stability of 1st level temperature control is about 0.1 °C and the max cool down capability is about 10 °C. The temperature field is analyzed in the 2nd and 3rd level temperature control using the finite element analysis software ANSYS. The 2nd and 3rd level temperature control optimization scheme is based on the foundation of heat analysis. The experimental results show that static accuracy of SGA-WZ-02 reaches 0.21 mGal/24 h, with internal accuracy being 0.743 mGal/4.8 km and external accuracy being 0.37 mGal/4.8 km compared with the result of the GT-2A, whose internal precision is superior to 1 mGal/4.8 km and all of them are better than those in SGA-WZ-01.

A flight test of the strapdown airborne gravimeter SGA-WZ in Greenland

DEFF Research Database (Denmark)

Zhao, Lei; Forsberg, René; Wu, Meiping

2015-01-01

-WZ strapdown airborne gravimeter in Greenland, in an area with good gravity coverage from earlier marine and airborne surveys. An overview of this new system SGA-WZ is given, including system design, sensor performance and data processing. The processing of the SGA-WZ includes a 160 s length finite impulse...

Anisotropy in superconducting gap in YBa2Cu3O7-δ

Science.gov (United States)

Verma, Sanjeev K.; Kumari, Anita; Gupta, Anushri; Indu, B. D.

2018-04-01

Taking into account the modified form of Born-Mayer-Huggins potential (MBMHP) and many body quantum dynamics based Green's function theory via a modified Hamiltonian which includes the effects of electrons, phonons, anharmonicities, defects and electron-phonon interactions; the quasiparticle renormalized frequency has been obtained and numerically analyzed for high temperature superconductor (HTS) cuprate YBa2Cu3O7-δ. This evaluation enables one to calculate superconducting gap (SG) in [100] and [010] direction through the dispersion of renormalized mode. A higher SG found in [010] than [100] direction at different doping level establishing its anisotropic nature.

Quantum fluctuations in the competition among spin glass, antiferromagnetism and local pairing superconductivity

International Nuclear Information System (INIS)

Magalhaes, S.G.; Zimmer, F.M.; Kipper, C.J.; Calegari, E.J.

2007-01-01

The competition among spin glass (SG), antiferromagnetism (AF) and local pairing superconductivity (PAIR) is studied in a two-sublattice fermionic Ising SG model with a local BCS pairing interaction in the presence of a transverse magnetic field Γ. The spins in different sublattices interact with Gaussian random couplings with an antiferromagnetic mean. The problem is formulated in a Grassmann path integral formalism. The static ansatz and the replica symmetry are used to obtain the half-filling thermodynamic potential. The results are shown in phase diagrams that exhibit a complex transition line separating the PAIR phase from the others. This line is second order at high temperature which ends in a tricritical point. The presence of Γ affects deeply the transition lines

Gravity and Height Variations at Medicina, Italy

Science.gov (United States)

Bruni, Sara; Zerbini, Susanna; Errico, Maddalena; Santi, Efisio; Wziontek, Hartmut

2017-04-01

Since 1996, at the Medicina station, height and gravity variations are monitored continuously by means of GPS, VLBI and superconducting gravimeter (SG) data. Additionally, absolute gravity observations are performed twice a year and environmental parameters, among others water table levels, are regularly acquired. Levelling between the different monuments at the site area is also carried out repeatedly to constrain local ties in the vertical position. Two GPS systems are located very close to each other, and both are in close proximity to the VLBI antenna. Twenty years of data are now available, which allow investigating both long- and short-period height and gravity signals together with their relevant correlations. Natural land subsidence, which is well known to occur in the area, is a major component of the observed long-term behavior; however, non-linear long-period signatures are also present in the time series. On a shorter time scale, fingerprints of the water table seasonal oscillations can be recognized in the data. The Medicina site is characterized by clayey soil subjected to consolidation effects when the water table lowers during summer periods. The pillar on which the SG is installed is especially affected because of its shallow foundation, causing height decreases in the order of 2.5-3 cm for water table lowering of 2 m. This study presents a comparative analysis of the different data sets with the aim of separating mass and deformation contributions in the SG gravity record.

[In silico CRISPR-based sgRNA design].

Science.gov (United States)

Wang, Yuanli; Chuai, Guohui; Yan, Jifang; Shi, Lei; Liu, Qi

2017-10-25

CRISPR-based genome editing has been widely implemented in various cell types. In-silico single guide RNA (sgRNA) design is a key step for successful gene editing using CRISPR system. Continuing efforts are made to refine in-silico sgRNA design with high on-target efficacy and reduced off-target effects. In this paper, we summarize the present sgRNA design tools, and show that efficient in-silico models can be built that integrate current heterogeneous genome-editing data to derive unbiased sgRNA design rules and identify key features for improving sgRNA design. Our review shows that systematic comparisons and evaluation of on-target and off-target effects of sgRNA will allow more precise genome editing and gene therapies using the CRISPR system.

Noise Reduction, Atmospheric Pressure Admittance Estimation and Long-Period Component Extraction in Time-Varying Gravity Signals Using Ensemble Empirical Mode Decomposition

Directory of Open Access Journals (Sweden)

Linsong Wang

2015-01-01

Full Text Available Time-varying gravity signals, with their nonlinear, non-stationary and multi-scale characteristics, record the physical responses of various geodynamic processes and consist of a blend of signals with various periods and amplitudes, corresponding to numerous phenomena. Superconducting gravimeter (SG records are processed in this study using a multi-scale analytical method and corrected for known effects to reduce noise, to study geodynamic phenomena using their gravimetric signatures. Continuous SG (GWR-C032 gravity and barometric data are decomposed into a series of intrinsic mode functions (IMFs using the ensemble empirical mode decomposition (EEMD method, which is proposed to alleviate some unresolved issues (the mode mixing problem and the end effect of the empirical mode decomposition (EMD. Further analysis of the variously scaled signals is based on a dyadic filter bank of the IMFs. The results indicate that removing the high-frequency IMFs can reduce the natural and man-made noise in the data, which are caused by electronic device noise, Earth background noise and the residual effects of pre-processing. The atmospheric admittances based on frequency changes are estimated from the gravity and the atmospheric pressure IMFs in various frequency bands. These time- and frequency-dependent admittance values can be used effectively to improve the atmospheric correction. Using the EEMD method as a filter, the long-period IMFs are extracted from the SG time-varying gravity signals spanning 7 years. The resulting gravity residuals are well correlated with the gravity effect caused by the _ polar motion after correcting for atmospheric effects.

Radio-Frequency Illuminated Superconductive Disks: Reverse Josephson Effects and Implications for Precise Measuring of Proposed Gravity Effects

Science.gov (United States)

Noever, David A.; Koczor, Ronald J.

1998-01-01

We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of large bulk-processed high-temperature superconductors. It have been indicated three essential components to achieve anomalous gravity effects, namely large, two-layer high-temperature YBCO superconductors, magnetic levitation and AC input in the form of radio-frequency (RF) electromagnetic fields. We report experiments on RF-illuminated (1-15 MHz) superconducting disks with corresponding gravity readings indicating an apparent increase in observed gravity of approximately 3-5 x l0(exp -5)cm/sq s, above and to the side of the superconductor. In this preliminary study, RF- illumination is achieved using a series of large radius (15 cm) spiral antenna with RF power inputs equal to or greater than 90 W. The observed gravitational modification range is significantly lower than the 2.1% gravity modification. The error analyses of thermal and electromagnetic interference in a magnetically shielded gravimeter with vacuum enclosures, Faraday cages and shielded instrument leads, are outlined both experimentally and theoretically. The nearly exact correspondence between the peak gravity effects reported and the well-known peak in AC resistance in superconductors (2-7 MHz, owing to reverse Josephson quantum effects) suggests that electrical resistance will arise in this frequency range and subsequently any trapped magnetic fields in the superconductor may disperse partially into the measuring instrument's local environment. Implications for propulsion initiatives and RF-heating in superconductors will be discussed.

Separating Mass and Height Contributions in Gravity Variations at Medicina, Italy

Science.gov (United States)

Zerbini, S.; Bruni, S.; Errico, M.; Santi, E.; Wziontek, H.

2016-12-01

During 1996, at the Medicina station, a GPS and a superconducting gravimeter (SG) were installed in the framework of an experiment focused on the comparison between height and gravity variations. Absolute gravity observations are also performed twice a year and environmental parameters, among others water table levels, are recorded continuously. The station is also equipped with a second GPS system, the two antennas are very close to each other, and both are located in close proximity to the VLBI dish. Two decades of continuous height and gravity observations are now available which allow investigating both long and short period signals and the relevant correlations between the two measured quantities. Long period signatures are observed, a principal component is due to subsidence which is well known to occur in the area; however, also non-linear long-period behaviors are observed. Seasonal effects are also clearly recognizable in the time series and are mainly associated with the water table seasonal behavior. The station is characterized by clayey soil which is subject to consolidation effects when the water table lowers during the summer period. This effect is particularly recognizable in the SG data since the instrument is installed on a shallow foundation pillar which may suffer for height decreases in the order of 2,5-3 cm for water table lowering of 2 m.

Life management of SG for WWER plants

International Nuclear Information System (INIS)

Trunov, N. B.; Dragunov, Yu. G.; Banyuk, G. F.

2004-01-01

Nowadays, 252 steam generators (SG) of horizontal type are in operation at WWER plants constructed by the Russian designs. In connection with end of the specified service life of the reactor plant equal to 30 years the activities are performed on service life extension of the main equipment including the SG. At some Units, throughout the design service life of SG there were problems resulting in necessity of SG replacement. At the same time the SGs at some Units are in successful operation above the design service life. This report deals with the peculiarities of operation of the horizontal SGs and the problems to be highlighted as the most important for service life extension. The main component to determine possibility for SG service life extension is the SG tubing. As the operating experience shows it is water chemistry of the secondary circuit that is the main factor influencing operability of the SG tubing. Therefore, differences in water chemistry organization leads to significant differences in operability of the SG tubing at various Units and in some cases within one Unit. Owing to the fact that the cases of water chemistry disturbance and the process of tubes fouling with the corrosion products of the main condensate system are not excluded, the damages continue to occur. Tube integrity shall be inspected by eddy current method using the various instrument complexes. This method has certain disadvantages but allows to estimate the degree and direction of degradation processes. The results of eddy current test (ECT) can be used to determine the plugging criterion for defective tubes. The significant number of defective tubes at some Units makes a choice of the plugging criterion to be an important problem, on which solution the SG safety, reliability and service life depends. The report deals with directions of activities in service life management for the SG at WWER plants. Main activities are improvement of water chemistry and non-destructive tests.(author)

Mapping the absolute magnetic field and evaluating the quadratic Zeeman-effect-induced systematic error in an atom interferometer gravimeter

Science.gov (United States)

Hu, Qing-Qing; Freier, Christian; Leykauf, Bastian; Schkolnik, Vladimir; Yang, Jun; Krutzik, Markus; Peters, Achim

2017-09-01

Precisely evaluating the systematic error induced by the quadratic Zeeman effect is important for developing atom interferometer gravimeters aiming at an accuracy in the μ Gal regime (1 μ Gal =10-8m /s2 ≈10-9g ). This paper reports on the experimental investigation of Raman spectroscopy-based magnetic field measurements and the evaluation of the systematic error in the gravimetric atom interferometer (GAIN) due to quadratic Zeeman effect. We discuss Raman duration and frequency step-size-dependent magnetic field measurement uncertainty, present vector light shift and tensor light shift induced magnetic field measurement offset, and map the absolute magnetic field inside the interferometer chamber of GAIN with an uncertainty of 0.72 nT and a spatial resolution of 12.8 mm. We evaluate the quadratic Zeeman-effect-induced gravity measurement error in GAIN as 2.04 μ Gal . The methods shown in this paper are important for precisely mapping the absolute magnetic field in vacuum and reducing the quadratic Zeeman-effect-induced systematic error in Raman transition-based precision measurements, such as atomic interferometer gravimeters.

A Moire-deflectometer as gravimeter for antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Haupert, Fabienne Catherine

2012-02-02

AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) - one of the experiments carried out at CERN - aims to examine fundamental physical properties of antimatter, in order to promote knowledge about the incompatibility of gravitation with other forces. As part of achieving this knowledge, the experiment will measure in its first phase the gravitational acceleration g of antihydrogen with a precision of 1% and hence, provide data for a deeper understanding of antimatter in general. A Moire-deflectometer is applied as gravimeter for this measurement. Its design and construction are carried out in Heidelberg. In order to test and characterise this deflectometer to its best achieveable sensitivity, a high-flux source of metastable argon atoms as well as a Faraday cup to detect these atoms are built. An additional optical Mach-Zehnder interferometer controls the stability of the apparatus. The major components of the deflectometer, the deflection gratings, are manufactured out of six-inch silicon wafers. Their prototypes together with the entire apparatus are designed and built with due care to account for the experimental conditions given by the apparatus at CERN. A first gravitational measurement with the test setup at Heidelberg yields g=(9.5{+-}1.9)(m)/(s{sup 2}) and opens up a huge number of potential improvements.

Relativistic theory of the falling retroreflector gravimeter

Science.gov (United States)

Ashby, Neil

2018-02-01

We develop a relativistic treatment of interference between light reflected from a falling cube retroreflector in the vertical arm of an interferometer, and light in a reference beam in the horizontal arm. Coordinates that are nearly Minkowskian, attached to the falling cube, are used to describe the propagation of light within the cube. Relativistic effects such as the dependence of the coordinate speed of light on gravitational potential, propagation of light along null geodesics, relativity of simultaneity, and Lorentz contraction of the moving cube, are accounted for. The calculation is carried to first order in the gradient of the acceleration of gravity. Analysis of data from a falling cube gravimeter shows that the propagation time of light within the cube itself causes a significant reduction in the value of the acceleration of gravity obtained from measurements, compared to assuming reflection occurs at the face. An expression for the correction to g is derived and found to agree with experiment. Depending on the instrument, the correction can be several microgals, comparable to commonly applied corrections such as those due to polar motion and earth tides. The controversial ‘speed of light’ correction is discussed. Work of the US government, not subject to copyright.

Benchmarking CRISPR on-target sgRNA design.

Science.gov (United States)

Yan, Jifang; Chuai, Guohui; Zhou, Chi; Zhu, Chenyu; Yang, Jing; Zhang, Chao; Gu, Feng; Xu, Han; Wei, Jia; Liu, Qi

2017-02-15

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-based gene editing has been widely implemented in various cell types and organisms. A major challenge in the effective application of the CRISPR system is the need to design highly efficient single-guide RNA (sgRNA) with minimal off-target cleavage. Several tools are available for sgRNA design, while limited tools were compared. In our opinion, benchmarking the performance of the available tools and indicating their applicable scenarios are important issues. Moreover, whether the reported sgRNA design rules are reproducible across different sgRNA libraries, cell types and organisms remains unclear. In our study, a systematic and unbiased benchmark of the sgRNA predicting efficacy was performed on nine representative on-target design tools, based on six benchmark data sets covering five different cell types. The benchmark study presented here provides novel quantitative insights into the available CRISPR tools. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ein Moiré-Deflektometer als Gravimeter für Antiwasserstoff

CERN Document Server

Haupert, Fabienne Cathérine

AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) – one of the experiments carried out at CERN – aims to examine fundamental physical properties of antimatter, in order to promote knowledge about the incompatibility of gravitation with other forces. As part of achieving this knowledge, the experiment will measure in its first phase the gravitational acceleration g of antihydrogen with a precision of 1% and hence, provide data for a deeper understanding of antimatter in general. A Moiré-deflectometer is applied as gravimeter for this measurement. Its design and construction are carried out in Heidelberg. In order to test and characterise this deflectometer to its best achieveable sensitivity, a high-flux source of metastable argon atoms as well as a Faraday cup to detect these atoms are built. An additional optical Mach-Zehnder interferometer controls the stability of the apparatus. The major components of the deflectometer, the deflection gratings, are manufactured out of six-inch sili...

Designing sgRNAs with CRISPy web

DEFF Research Database (Denmark)

Blin, Kai; Lee, Sang Yup; Weber, Tilmann

2017-01-01

Tilmann Weber’s group at the Novo Nordisk Foundation Center for Biosustainability developed a user-friendly, web server implementation of the sgRNA prediction software, CRISPy, for non-computer scientists.......Tilmann Weber’s group at the Novo Nordisk Foundation Center for Biosustainability developed a user-friendly, web server implementation of the sgRNA prediction software, CRISPy, for non-computer scientists....

Relative gravimeter prototype based on micro electro mechanical system

Science.gov (United States)

Rozy, A. S. A.; Nugroho, H. A.; Yusuf, M.

2018-03-01

This research to make gravity measurement system by utilizing micro electro mechanical system based sensor in Gal order. System design consists of three parts, design of hardware, software, and interface. The design of the hardware include of designing the sensor design to measure the value of a stable gravity acceleration. The ADXL345 and ADXL335 sensors are tuned to obtain stable measurements. The design of the instrumentation system the next stage by creating a design to integrate between the sensor, microcontroller, and GPS. The design of programming algorithm is done with Arduino IDE software. The interface design uses a 20x4 LCD display to display the gravity acceleration value and store data on the storage media. The system uses a box made of iron and plate leveling to minimize measurement errors. The sensor test shows the ADXL345 sensor has a more stable value. The system is examined by comparing with gravity measurement of gravimeter A-10 results in Bandung observation post. The result of system test resulted the average of system correction value equal to 0.19 Gal. The system is expected to use for mineral exploration, water supply analyze, and earthquake precursor.

Development of a graphical user interface for sgRNAcas9 and its application.

Science.gov (United States)

Zhao, Chang-zhi; Zhang, Yi; Li, Guang-lei; Chen, Ji-liang; Li, Jing-Jin; Ren, Rui-min; Ni, Pan; Zhao, Shu-hong; Xie, Sheng-song

2015-10-01

The CRISPR/Cas9 genome editing technique is a powerful tool for researchers. However, off-target effects of the Cas9 nuclease activity is a recurrent concern of the CRISPR system. Thus, designing sgRNA (single guide RNA) with minimal off-target effects is very important. sgRNAcas9 is a software package, which can be used to design sgRNA and to evaluate potential off-target cleavage sites. In this study, a graphical user interface for sgRNAcas9 was developed using the Java programming language. In addition, off-target effect for sgRNAs was evaluated according to mismatched number and "seed sequence" specification. Moreover, sgRNAcas9 software was used to design 34 124 sgRNAs, which can target 4691 microRNA (miRNA) precursors from human, mouse, rat, pig, and chicken. In particular, the off-target effect of a sgRNA targeting to human miR-206 precursor was analyzed, and the on/off-target activity of this sgRNA was validated by T7E1 assay in vitro. Taken together, these data showed that the interface can simplify the usage of the sgRNAcas9 program, which can be used to design sgRNAs for the majority of miRNA precursors. We also found that the GC% of those sgRNAs ranged from 40% to 60%. In summary, the sgRNAcas9 software can be easily used to design sgRNA with minimal off-target effects for any species. The software can be downloaded from BiooTools website (http://www.biootools.com/).

Recent progress in SG level control in French PWR plants

International Nuclear Information System (INIS)

Parry, A.; Petetrot, J.F.; Vivier, M.J.

1985-10-01

Controlling the steam generator (SG) level is of major importance in a large PWR plant. This has led to extensive work on SG computer models. This paper presents results of the comparison between calculations and tests on the first four-loop plant in France. Four-loop plants started up after 1985 will be equipped with digital instead of analog controllers. A new SG level control has been designed and then optimised using the validated SG model. A prototype of this new system has been successfully tested on a three-loop plant. 4 refs

Laser performance upgrade for precise ICF experiment in SG-Ⅲ laser facility

Directory of Open Access Journals (Sweden)

Wanguo Zheng

2017-09-01

Full Text Available The SG-Ⅲ laser facility (SG-Ⅲ is the largest laser driver for inertial confinement fusion (ICF researches in China, which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns. In order to meet the requirements of precise physics experiments, some new functionalities need to be added to SG-Ⅲ and some intrinsic laser performances need upgrade. So at the end of SG-Ⅲ's engineering construction, the 2-year laser performance upgrade project started. This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ. With these function extensions and performance upgrade, SG-Ⅲ is now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.

Field experience with KWU SG chemical cleaning process

International Nuclear Information System (INIS)

Odar, S.

1989-01-01

The ingress of corrosion products into PWR steam generators (SG's) their deposition and the subsequent concentration of salt impurities can induce a variety of mechanisms for corrosion attack on SG tubing. Already, some plants have had to replace their steam generators due to severe corrosion damage and others are seriously considering the same costly action in the near future. One of the most effective ways to counteract corrosion mechanisms and thus to reduce the likelihood of SG replacement becoming necessary is to clean the SG's and to keep them clean. For many years, the industry has been involved in developing different types of cleaning techniques. Among these, chemical cleaning has been shown to be especially effective. In this article, the KWU chemical cleaning process, for which there is considerable application experience, is described. The results of field applications will be presented together with material compatibility data and information on cleaning effectiveness. (author)

Superconductivity

International Nuclear Information System (INIS)

Palmieri, V.

1990-01-01

This paper reports on superconductivity the absence of electrical resistance has always fascinated the mind of researchers with a promise of applications unachievable by conventional technologies. Since its discovery superconductivity has been posing many questions and challenges to solid state physics, quantum mechanics, chemistry and material science. Simulations arrived to superconductivity from particle physics, astrophysic, electronics, electrical engineering and so on. In seventy-five years the original promises of superconductivity were going to become reality: a microscopical theory gave to superconductivity the cloth of the science and the level of technological advances was getting higher and higher. High field superconducting magnets became commercially available, superconducting electronic devices were invented, high field accelerating gradients were obtained in superconductive cavities and superconducting particle detectors were under study. Other improvements came in a quiet progression when a tornado brought a revolution in the field: new materials had been discovered and superconductivity, from being a phenomenon relegated to the liquid Helium temperatures, became achievable over the liquid Nitrogen temperature. All the physics and the technological implications under superconductivity have to be considered ab initio

In Silico Meets In Vivo: Towards Computational CRISPR-Based sgRNA Design.

Science.gov (United States)

Chuai, Guo-Hui; Wang, Qi-Long; Liu, Qi

2017-01-01

CRISPR-based genome editing has been widely implemented in various cell types. In silico single guide RNA (sgRNA) design is a key step for successful gene editing using the CRISPR system, and continuing efforts are aimed at refining in silico sgRNA design with high on-target efficacy and reduced off-target effects. Many sgRNA design tools are available, but careful assessments of their application scenarios and performance benchmarks across different types of genome-editing data are needed. Efficient in silico models can be built that integrate current heterogeneous genome-editing data to derive unbiased sgRNA design rules and identify key features for improving sgRNA design. Comprehensive evaluation of on-target and off-target effects of sgRNA will allow more precise genome editing and gene therapies using the CRISPR system. Copyright © 2016 Elsevier Ltd. All rights reserved.

CRISPRscan: designing highly efficient sgRNAs for CRISPR/Cas9 targeting in vivo

Science.gov (United States)

Moreno-Mateos, Miguel A.; Vejnar, Charles E.; Beaudoin, Jean-Denis; Fernandez, Juan P.; Mis, Emily K.; Khokha, Mustafa K.; Giraldez, Antonio J.

2015-01-01

CRISPR/Cas9 technology provides a powerful system for genome engineering. However, variable activity across different single guide RNAs (sgRNAs) remains a significant limitation. We have analyzed the molecular features that influence sgRNA stability, activity and loading into Cas9 in vivo. We observe that guanine enrichment and adenine depletion increase sgRNA stability and activity, while loading, nucleosome positioning and Cas9 off-target binding are not major determinants. We additionally identified truncated and 5′ mismatch-containing sgRNAs as efficient alternatives to canonical sgRNAs. Based on these results, we created a predictive sgRNA-scoring algorithm (CRISPRscan.org) that effectively captures the sequence features affecting Cas9/sgRNA activity in vivo. Finally, we show that targeting Cas9 to the germ line using a Cas9-nanos-3′-UTR fusion can generate maternal-zygotic mutants, increase viability and reduce somatic mutations. Together, these results provide novel insights into the determinants that influence Cas9 activity and a framework to identify highly efficient sgRNAs for genome targeting in vivo. PMID:26322839

Wide cross-reactivity between Anopheles gambiae and Anopheles funestus SG6 salivary proteins supports exploitation of gSG6 as a marker of human exposure to major malaria vectors in tropical Africa

Directory of Open Access Journals (Sweden)

Petrarca Vincenzo

2011-07-01

Full Text Available Abstract Background The Anopheles gambiae gSG6 is an anopheline-specific salivary protein which helps female mosquitoes to efficiently feed on blood. Besides its role in haematophagy, gSG6 is immunogenic and elicits in exposed individuals an IgG response, which may be used as indicator of exposure to the main African malaria vector A. gambiae. However, malaria transmission in tropical Africa is sustained by three main vectors (A. gambiae, Anopheles arabiensis and Anopheles funestus and a general marker, reflecting exposure to at least these three species, would be especially valuable. The SG6 protein is highly conserved within the A. gambiae species complex whereas the A. funestus homologue, fSG6, is more divergent (80% identity with gSG6. The aim of this study was to evaluate cross-reactivity of human sera to gSG6 and fSG6. Methods The A. funestus SG6 protein was expressed/purified and the humoral response to gSG6, fSG6 and a combination of the two antigens was compared in a population from a malaria hyperendemic area of Burkina Faso where both vectors were present, although with a large A. gambiae prevalence (>75%. Sera collected at the beginning and at the end of the high transmission/rainy season, as well as during the following low transmission/dry season, were analysed. Results According to previous observations, both anti-SG6 IgG level and prevalence decreased during the low transmission/dry season and showed a typical age-dependent pattern. No significant difference in the response to the two antigens was found, although their combined use yielded in most cases higher IgG level. Conclusions Comparative analysis of gSG6 and fSG6 immunogenicity to humans suggests the occurrence of a wide cross-reactivity, even though the two proteins carry species-specific epitopes. This study supports the use of gSG6 as reliable indicator of exposure to the three main African malaria vectors, a marker which may be useful to monitor malaria transmission

Superconductivity

CERN Document Server

Thomas, D B

1974-01-01

A short general review is presented of the progress made in applied superconductivity as a result of work performed in connection with the high-energy physics program in Europe. The phenomenon of superconductivity and properties of superconductors of Types I and II are outlined. The main body of the paper deals with the development of niobium-titanium superconducting magnets and of radio-frequency superconducting cavities and accelerating structures. Examples of applications in and for high-energy physics experiments are given, including the large superconducting magnet for the Big European Bubble Chamber, prototype synchrotron magnets for the Super Proton Synchrotron, superconducting d.c. beam line magnets, and superconducting RF cavities for use in various laboratories. (0 refs).

Melt formed superconducting joint between superconducting tapes

International Nuclear Information System (INIS)

Benz, M.G.; Knudsen, B.A.; Rumaner, L.E.; Zaabala, R.J.

1992-01-01

This patent describes a superconducting joint between contiguous superconducting tapes having an inner laminate comprised of a parent-metal layer selected from the group niobium, tantalum, technetium, and vanadium, a superconductive intermetallic compound layer on the parent-metal layer, a reactive-metal layer that is capable of combining with the parent-metal and forming the superconductive intermetallic compound, the joint comprising: a continuous precipitate of the superconductive intermetallic compound fused to the tapes forming a continuous superconducting path between the tapes

Antagonistic action of Bacillus subtilis strain SG6 on Fusarium graminearum.

Science.gov (United States)

Zhao, Yueju; Selvaraj, Jonathan Nimal; Xing, Fuguo; Zhou, Lu; Wang, Yan; Song, Huimin; Tan, Xinxin; Sun, Lichao; Sangare, Lancine; Folly, Yawa Minnie Elodie; Liu, Yang

2014-01-01

Fusarium graminearum causes Fusarium head blight (FHB), a devastating disease that leads to extensive yield and quality loss of wheat and barley. Bacteria isolated from wheat kernels and plant anthers were screened for antagonistic activity against F. graminearum. Based on its in vitro effectiveness, strain SG6 was selected for characterization and identified as Bacillus subtilis. B. subtilis SG6 exhibited a high antifungal effect on the mycelium growth, sporulation and DON production of F. graminearum with the inhibition rate of 87.9%, 95.6% and 100%, respectively. In order to gain insight into biological control effect in situ, we applied B. subtilis SG6 at anthesis through the soft dough stage of kernel development in field test. It was revealed that B. subtilis SG6 significantly reduced disease incidence (DI), FHB index and DON (P ≤ 0.05). Further, ultrastructural examination shows that B. subtilis SG6 strain induced stripping of F. graminearum hyphal surface by destroying the cellular structure. When hypha cell wall was damaged, the organelles and cytoplasm inside cell would exude, leading to cell death. The antifungal activity of SG6 could be associated with the coproduction of chitinase, fengycins and surfactins.

Antagonistic action of Bacillus subtilis strain SG6 on Fusarium graminearum.

Directory of Open Access Journals (Sweden)

Yueju Zhao

Full Text Available Fusarium graminearum causes Fusarium head blight (FHB, a devastating disease that leads to extensive yield and quality loss of wheat and barley. Bacteria isolated from wheat kernels and plant anthers were screened for antagonistic activity against F. graminearum. Based on its in vitro effectiveness, strain SG6 was selected for characterization and identified as Bacillus subtilis. B. subtilis SG6 exhibited a high antifungal effect on the mycelium growth, sporulation and DON production of F. graminearum with the inhibition rate of 87.9%, 95.6% and 100%, respectively. In order to gain insight into biological control effect in situ, we applied B. subtilis SG6 at anthesis through the soft dough stage of kernel development in field test. It was revealed that B. subtilis SG6 significantly reduced disease incidence (DI, FHB index and DON (P ≤ 0.05. Further, ultrastructural examination shows that B. subtilis SG6 strain induced stripping of F. graminearum hyphal surface by destroying the cellular structure. When hypha cell wall was damaged, the organelles and cytoplasm inside cell would exude, leading to cell death. The antifungal activity of SG6 could be associated with the coproduction of chitinase, fengycins and surfactins.

Frequent sgRNA-barcode recombination in single-cell perturbation assays.

Directory of Open Access Journals (Sweden)

Shiqi Xie

Full Text Available Simultaneously detecting CRISPR-based perturbations and induced transcriptional changes in the same cell is a powerful approach to unraveling genome function. Several lentiviral approaches have been developed, some of which rely on the detection of distally located genetic barcodes as an indirect proxy of sgRNA identity. Since barcodes are often several kilobases from their corresponding sgRNAs, viral recombination-mediated swapping of barcodes and sgRNAs is feasible. Using a self-circularization-based sgRNA-barcode library preparation protocol, we estimate the recombination rate to be ~50% and we trace this phenomenon to the pooled viral packaging step. Recombination is random, and decreases the signal-to-noise ratio of the assay. Our results suggest that alternative approaches can increase the throughput and sensitivity of single-cell perturbation assays.

Superconductivity

CERN Document Server

Poole, Charles P; Farach, Horacio A

1995-01-01

Superconductivity covers the nature of the phenomenon of superconductivity. The book discusses the fundamental principles of superconductivity; the essential features of the superconducting state-the phenomena of zero resistance and perfect diamagnetism; and the properties of the various classes of superconductors, including the organics, the buckministerfullerenes, and the precursors to the cuprates. The text also describes superconductivity from the viewpoint of thermodynamics and provides expressions for the free energy; the Ginzburg-Landau and BCS theories; and the structures of the high

Trash to Supply Gas (TtSG) Project Overview

Science.gov (United States)

Hintze, Paul; Santiago-Maldonado, Edgardo; Kulis, Michael J.; Lytle, John K.; Fisher, John W.; Vaccaro, Helen; Ewert, Michael K.; Broyan, James L.

2012-01-01

Technologies that reduce logistical needs are a key to long term space missions. Currently, trash and waste generated during a mission is carried during the entire roundtrip mission or stored inside a logistic module which is de-orbited into Earth's atmosphere for destruction. The goal of the Trash to Supply Gas (TtSG) project is to develop space technology alternatives for converting trash and other waste materials from human spaceflight into high-value products that might include propellants or power system fuels in addition to life support oxygen and water. In addition to producing a useful product from waste, TtSG will decrease the volume needed to store waste on long term space missions. This paper presents an overview of the TtSG technologies and future plans for the project.

Inclusive search for b → sg

International Nuclear Information System (INIS)

1998-07-01

The authors describe an inclusive search for flavor changing neutral current decays of the type b → s gluon in the SLD experiment. Models of b → sg indicate that the production of high momentum kaons is enhanced over background from standard B decays. If the branching ratio for b → sg is ∼ 10%, then such an enhancement should have a good signal to background ratio. The analysis makes use of the particle identification and high precision vertexing capabilities of SLD to search for such an enhancement. The data sample consists of 300K hadronic Z 0 decays collected between 1993 and 1997

Superconductivity

International Nuclear Information System (INIS)

Taylor, A.W.B.; Noakes, G.R.

1981-01-01

This book is an elementray introduction into superconductivity. The topics are the superconducting state, the magnetic properties of superconductors, type I superconductors, type II superconductors and a chapter on the superconductivity theory. (WL)

Superconductivity

International Nuclear Information System (INIS)

Onnes, H.K.

1988-01-01

The author traces the development of superconductivity from 1911 to 1986. Some of the areas he explores are the Meissner Effect, theoretical developments, experimental developments, engineering achievements, research in superconducting magnets, and research in superconducting electronics. The article also mentions applications shown to be technically feasible, but not yet commercialized. High-temperature superconductivity may provide enough leverage to bring these applications to the marketplace

Superconductivity

International Nuclear Information System (INIS)

Andersen, N.H.; Mortensen, K.

1988-12-01

This report contains lecture notes of the basic lectures presented at the 1st Topsoee Summer School on Superconductivity held at Risoe National Laboratory, June 20-24, 1988. The following lecture notes are included: L.M. Falicov: 'Superconductivity: Phenomenology', A. Bohr and O. Ulfbeck: 'Quantal structure of superconductivity. Gauge angle', G. Aeppli: 'Muons, neutrons and superconductivity', N.F. Pedersen: 'The Josephson junction', C. Michel: 'Physicochemistry of high-T c superconductors', C. Laverick and J.K. Hulm: 'Manufacturing and application of superconducting wires', J. Clarke: 'SQUID concepts and systems'. (orig.) With 10 tabs., 128 figs., 219 refs

Theory of superconductivity

International Nuclear Information System (INIS)

Crisan, M.

1988-01-01

This book discusses the most important aspects of the theory. The phenomenological model is followed by the microscopic theory of superconductivity, in which modern formalism of the many-body theory is used to treat most important problems such as superconducting alloys, coexistence of superconductivity with the magnetic order, and superconductivity in quasi-one-dimensional systems. It concludes with a discussion on models for exotic and high temperature superconductivity. Its main aim is to review, as complete as possible, the theory of superconductivity from classical models and methods up to the 1987 results on high temperature superconductivity. Contents: Phenomenological Theory of Superconductivity; Microscopic Theory of Superconductivity; Theory of Superconducting Alloys; Superconductors in a Magnetic Field; Superconductivity and Magnetic Order; Superconductivity in Quasi-One-Dimensional Systems; and Non-Conventional Superconductivity

Applied superconductivity

CERN Document Server

Newhouse, Vernon L

1975-01-01

Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec

Cloning and expression of SgCYP450-4 from Siraitia grosvenorii

Directory of Open Access Journals (Sweden)

Dongping Tu

2016-10-01

Full Text Available CYP450 plays an essential role in the development and growth of the fruits of Siraitia grosvenorii. However, little is known about the SgCYP450-4 gene in S. grosvenorii. Here, based on transcriptome data, a full-length cDNA sequence of SgCYP450-4 was cloned by reverse transcriptase-polymerase chain reaction (RT-PCR and rapid-amplification of cDNA ends (RACE strategies. SgCYP450-4 is 1677 bp in length (GenBank accession No. AEM42985.1 and contains a complete open reading frame (ORF of 1422 bp. The deduced protein was composed of 473 amino acids, the molecular weight is 54.01 kDa, the theoretical isoelectric point (PI is 8.8, and the protein was predicted to possess cytochrome P450 domains. SgCYP450-4 gene was highly expressed in root, diploid fruit and fruit treated with hormone and pollination. At 10 days after treatment with pollination and hormones, the expression of SgCYP450-4 had the highest level and then decreased over time, which was consistent with the development of fruits of S. Grosvenorii. Hormonal treatment could significantly induce the expression of SgCYP450-4. These results provide a reference for regulation of fruit development and the use of parthenocarpy to generate seedless fruit, and provide a scientific basis for the production of growth regulator application agents.

Advanced evaluation method of SG TSP BEC hole blockage rate

International Nuclear Information System (INIS)

Izumida, Hiroyuki; Nagata, Yasuyuki; Harada, Yutaka; Murakami, Ryuji

2003-01-01

In spite of the control of the water chemistry of SG secondary feed-water in PWR-SG, SG TSP BEC holes, which are the flow path of secondary water, are often clogged. In the past, the trending of BEC hole blockage rate has conducted by evaluating ECT original signals and visual inspections. However, the ECT original signals of deposits are diversified, it becomes difficult to analyze them with the existing evaluation method using the ECT original signals. In this regard, we have developed the secondary side visual inspection system, which enables the high-accuracy evaluation of BEC hole blockage rate, and new ECT signal evaluation method. (author)

Superconductivity

International Nuclear Information System (INIS)

Caruana, C.M.

1988-01-01

Despite reports of new, high-temperature superconductive materials almost every day, participants at the First Congress on Superconductivity do not anticipate commercial applications with these materials soon. What many do envision is the discovery of superconducting materials that can function at much warmer, perhaps even room temperatures. Others hope superconductivity will usher in a new age of technology as semiconductors and transistors did. This article reviews what the speakers had to say at the four-day congress held in Houston last February. Several speakers voiced concern that the Reagan administration's apparent lack of interest in funding superconductivity research while other countries, notably Japan, continue to pour money into research and development could hamper America's international competitiveness

Active Intracellular Delivery of a Cas9/sgRNA Complex Using Ultrasound-Propelled Nanomotors.

Science.gov (United States)

Hansen-Bruhn, Malthe; de Ávila, Berta Esteban-Fernández; Beltrán-Gastélum, Mara; Zhao, Jing; Ramírez-Herrera, Doris E; Angsantikul, Pavimol; Vesterager Gothelf, Kurt; Zhang, Liangfang; Wang, Joseph

2018-03-01

Direct and rapid intracellular delivery of a functional Cas9/sgRNA complex using ultrasound-powered nanomotors is reported. The Cas9/sgRNA complex is loaded onto the nanomotor surface through a reversible disulfide linkage. A 5 min ultrasound treatment enables the Cas9/sgRNA-loaded nanomotors to directly penetrate through the plasma membrane of GFP-expressing B16F10 cells. The Cas9/sgRNA is released inside the cells to achieve highly effective GFP gene knockout. The acoustic Cas9/sgRNA-loaded nanomotors display more than 80 % GFP knockout within 2 h of cell incubation compared to 30 % knockout using static nanowires. More impressively, the nanomotors enable highly efficient knockout with just 0.6 nm of the Cas9/sgRNA complex. This nanomotor-based intracellular delivery method thus offers an attractive route to overcome physiological barriers for intracellular delivery of functional proteins and RNAs, thus indicating considerable promise for highly efficient therapeutic applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimum Frequency for Eddy Current Testing Method of SMART SG tubes

International Nuclear Information System (INIS)

Lee, Yoon Sang; Jung, Hyun Kyu; Choung, Yun Hang

2009-01-01

The SMART SG tubes will be made of Alloy 690. The outside diameter will be 17 mm and the thickness will be 2.5 mm. They will be assembled helically around, and their innermost diameter will be about 600 mm and the total length will be about 32 meters. For safety, SMART SG tubes are designed for use with thick tubes such as 2.5 mm thickness compared to about 1 mm thickness of normal Korean standard pressurized water reactor tubes. Due to using thick tubes such as 2.5 mm varieties, it was doubted that the Eddy Current Testing Method (ECT) would be a feasible method. Therefore we are trying to simulate the bobbin probe signal for SMART SG tubes and comparing it to PWR SG ECT probe signal using VIM software, checking for the applicability of ECT. Also we are trying to compare the ECT signal of 2.5 mm thick stainless tubes to check if they are possible substitute material

Three years of high precision gravity measurements at the gravimetric station of Brasimone - Italy

Directory of Open Access Journals (Sweden)

G. Casula

1998-06-01

Full Text Available From August 1995 up to now, at the Enea Research Center of Brasimone, in the Italian Apennines between Bologna and Florence (Italy: 44º07'N, 11º.07'E, 890 m height, the superconducting gravimeter GWR model TT70 number T015 has been continuously recording the variation of the local gravity field, in the frame of the Global Geodynamics Project. The gravimetric laboratory, being a room of the disused nuclear power plant of Brasimone, is a very stable site, free from noise due to human activities. Data blocks of several months of continuous gravity records have been collected over a time span of three years, together with the meteorological data. The gravimeter has been calibrated at relative accuracy better than 0.3% with the aid of a mobile mass system, by imposed perturbations of the local gravity field and recording the gravimeter response. The results of this calibration technique were checked by two comparison experiments with absolute gravimeters performed during this period: the first, in May 1994 with the aid of the symmetrical rise and fall gravimeter of the Institute of Metrology Colonnetti of Turin, and the second in October 1997 involving an FG5 absolute gravimeter of the Institute de Physique du Globe of Strasbourg. The gravimeter signal was analysed to compute a high precision tidal model for Brasimone site. Starting from a set of gravimetric and atmospheric pressure data of high quality, relative to 46 months of observation, we performed the tidal analysis using Eterna 3.2 software to compute amplitudes, gravimetric factors and phases of the main waves of the Tamura catalogue. Finally a comparison experiment between two of the STS-1/VBB broadband seismometers of the MedNet project network and the gravity records relative to the Balleny Islands earthquake (March 25, 1998 were analysed to look for evidence of normal modes due to the free oscillations of the Earth.

Nondestructive evaluation of the QT on the SG tubes affected by chemical cleaning

Energy Technology Data Exchange (ETDEWEB)

Shin, Ki Seok Shin; Cheon, Keun Young; Kim, Wang Bae [Central Research Institute, Daejeon (Korea, Republic of); Min, Kyong Mahn [UMI, Daejeon (Korea, Republic of)

2012-10-15

The major mechanisms of flaws detected on the currently operating steam generator(SG) tubes are wear and stress corrosion cracking(SCC) defects. Wear defect has continuously occurred in the upper tube bundle imposed to the flow induced vibration at the interaction between tube and its support structure. Meanwhile, SCC has been formed by a variety of mixed mode, such as the corrosion susceptible material, residual stress and secondary side chemical environment of the SG tubes. Recently, corrosion related defects were detected in the domestic OPR 1000 model SG tubes especially in the egg crate tube support plate(TSP), as a form of axially oriented outer diameter stress corrosion cracking (ODSCC). Therefore, the need to take corrective measures against the corrosion defects is required and various studies have been conducted to clarify the main causes of the defects. In general, as a representing SG tube materials, Ni based alloy 600 tubes have been widely applied and also adversely shown weak properties on the corrosion cracking resistivity. According to the studies on the factors developing corrosion cracking, densely accumulated sludge pile on the secondary side of the SG tubes have been mainly attributed to the formation of the corrosion defects. Therefore, it is imperative to secure applicable and efficient sludge removal process. In this paper, the chemical cleaning processes to dissolve and remove the sludge, thus promote the integrity of the SG tubes were introduced and eddy current testing(ECT) results on the pre cracked SG tubes to determine the effectiveness of those processes were represented as well.

Interface superconductivity

Energy Technology Data Exchange (ETDEWEB)

Gariglio, S., E-mail: stefano.gariglio@unige.ch [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland); Gabay, M. [Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud 11, Centre d’Orsay, 91405 Orsay Cedex (France); Mannhart, J. [Max Planck Institute for Solid State Research, 70569 Stuttgart (Germany); Triscone, J.-M. [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland)

2015-07-15

Highlights: • We discuss interfacial superconductivity, a field boosted by the discovery of the superconducting interface between LaAlO. • This system allows the electric field control and the on/off switching of the superconducting state. • We compare superconductivity at the interface and in bulk doped SrTiO. • We discuss the role of the interfacially induced Rashba type spin–orbit. • We briefly discuss superconductivity in cuprates, in electrical double layer transistor field effect experiments. • Recent observations of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3} are presented. - Abstract: Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO{sub 3} and SrTiO{sub 3}. We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO{sub 3} and the interface system and the possible role of the interfacially induced Rashba type spin–orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3}.

Superconducting coil and method of stress management in a superconducting coil

Science.gov (United States)

McIntyre, Peter M.; Shen, Weijun; Diaczenko, Nick; Gross, Dan A.

1999-01-01

A superconducting coil (12) having a plurality of superconducting layers (18) is provided. Each superconducting layer (18) may have at least one superconducting element (20) which produces an operational load. An outer support structure (24) may be disposed outwardly from the plurality of layers (18). A load transfer system (22) may be coupled between at least one of the superconducting elements (20) and the outer support structure (24). The load transfer system (22) may include a support matrix structure (30) operable to transfer the operational load from the superconducting element (20) directly to the outer support structure (24). A shear release layer (40) may be disposed, in part, between the superconducting element (20) and the support matrix structure (30) for relieving a shear stress between the superconducting element (20) and the support matrix structure (30). A compliant layer (42) may also be disposed, in part, between the superconducting element (20) and the support matrix structure (30) for relieving a compressive stress on the superconducting element (20).

Superconductivity

International Nuclear Information System (INIS)

Kakani, S.L.; Kakani, Shubhra

2007-01-01

The monograph provides readable introduction to the basics of superconductivity for beginners and experimentalists. For theorists, the monograph provides nice and brief description of the broad spectrum of experimental properties, theoretical concepts with all details, which theorists should learn, and provides a sound basis for students interested in studying superconducting theory at the microscopic level. Special chapter on the theory of high-temperature superconductivity in cuprates is devoted

Structural integrity evaluation of SG tube with surface wear-type defects

International Nuclear Information System (INIS)

Kim, Jong Min; Huh, Nam Su; Chang, Yoon Suk; Kim, Young Jin; Hwang, Seong Sik; Kim, Joung Soo

2006-01-01

During the last two decades, several guidelines have been developed and used for assessing the integrity of a defective Steam Generator (SG) tube that is generally caused by stress corrosion cracking or wall-thinning phenomenon. However, as some of SG tubes are also failed due to fretting and so on, alternative failure estimation schemes are required for relevant defects. In this paper, parametric three-dimensional Finite Element (FE) analyses are carried out under internal pressure condition to simulate the failure behavior of SG tubes with different defect configurations; elliptical wear, tapered and flat wear type defects. Maximum pressures based on material strengths are obtained from more than a hundred FE results to predict the failure of SG tube. After investigating the effect of key parameters such as defect depth, defect length and wrap angle, simplified failure estimation equations are proposed in relation to the equivalent stress at the deepest point in wear region. Comparison of failure pressures predicted by the proposed estimation scheme with corresponding burst test data showed a good agreement

Whole genome analysis of CRISPR Cas9 sgRNA off-target homologies via an efficient computational algorithm.

Science.gov (United States)

Zhou, Hong; Zhou, Michael; Li, Daisy; Manthey, Joseph; Lioutikova, Ekaterina; Wang, Hong; Zeng, Xiao

2017-11-17

The beauty and power of the genome editing mechanism, CRISPR Cas9 endonuclease system, lies in the fact that it is RNA-programmable such that Cas9 can be guided to any genomic loci complementary to a 20-nt RNA, single guide RNA (sgRNA), to cleave double stranded DNA, allowing the introduction of wanted mutations. Unfortunately, it has been reported repeatedly that the sgRNA can also guide Cas9 to off-target sites where the DNA sequence is homologous to sgRNA. Using human genome and Streptococcus pyogenes Cas9 (SpCas9) as an example, this article mathematically analyzed the probabilities of off-target homologies of sgRNAs and discovered that for large genome size such as human genome, potential off-target homologies are inevitable for sgRNA selection. A highly efficient computationl algorithm was developed for whole genome sgRNA design and off-target homology searches. By means of a dynamically constructed sequence-indexed database and a simplified sequence alignment method, this algorithm achieves very high efficiency while guaranteeing the identification of all existing potential off-target homologies. Via this algorithm, 1,876,775 sgRNAs were designed for the 19,153 human mRNA genes and only two sgRNAs were found to be free of off-target homology. By means of the novel and efficient sgRNA homology search algorithm introduced in this article, genome wide sgRNA design and off-target analysis were conducted and the results confirmed the mathematical analysis that for a sgRNA sequence, it is almost impossible to escape potential off-target homologies. Future innovations on the CRISPR Cas9 gene editing technology need to focus on how to eliminate the Cas9 off-target activity.

Superconductivity

International Nuclear Information System (INIS)

Langone, J.

1989-01-01

This book explains the theoretical background of superconductivity. Includes discussion of electricity, material fabrication, maglev trains, the superconducting supercollider, and Japanese-US competition. The authors reports the latest discoveries

ac superconducting articles

International Nuclear Information System (INIS)

Meyerhoff, R.W.

1977-01-01

A noval ac superconducting cable is described. It consists of a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface

High-temperature superconductivity

International Nuclear Information System (INIS)

Ginzburg, V.L.

1987-07-01

After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

Superconducting accelerator technology

International Nuclear Information System (INIS)

Grunder, H.A.; Hartline, B.K.

1986-01-01

Modern and future accelerators for high energy and nuclear physics rely increasingly on superconducting components to achieve the required magnetic fields and accelerating fields. This paper presents a practical overview of the phenomenon of superconductivity, and describes the design issues and solutions associated with superconducting magnets and superconducting rf acceleration structures. Further development and application of superconducting components promises increased accelerator performance at reduced electric power cost

WPEC Subgroup Meetings. Joint SG39/SG40-CIELO meeting, 14 May 2014

International Nuclear Information System (INIS)

Chadwick, M.; Yokoyama, Kenji; Ishikawa, M.; Archier, P.; Palmiotti, G.; Salvatores, Massimo; Dupont, E.; ); Leal, L.

2014-05-01

The aim of WPEC subgroup 39 'Methods and approaches to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data files' is to provide criteria and practical approaches to use effectively the results of sensitivity analyses and cross section adjustments for feedback to evaluators and differential measurement experimentalists in order to improve the knowledge of neutron cross sections, uncertainties, and correlations to be used in a wide range of applications. WPEC subgroup 40-CIELO (Collaborative International Evaluated Library Organization) provides a new working paradigm to facilitate evaluated nuclear reaction data advances. It brings together experts from across the international nuclear reaction data community to identify and document discrepancies among existing evaluated data libraries, measured data, and model calculation interpretations, and aims to make progress in reconciling these discrepancies to create more accurate ENDF-formatted files. SG40-CIELO focusses on 6 important isotopes: "1H, "1"6O, "5"6Fe, "2"3"5","2"3"8U, "2"3"9Pu. This document is the proceedings of the Joint SG39/SG40-CIELO meeting, held at the NEA, Issy-les-Moulineaux, France, on 19-20 May 2015. It comprises all the available presentations (slides) given by the participants: 1 - CIELO Progress (M. Chadwick); 2 - Revised Recommendations from ADJ2010 Adjustment (K. Yokoyama); 3 - Comparisons and Discussions on Adjustment trends from JEFF (CEA) (P. Archier); 4 - Feedback on CIELO Isotopes from ENDF/B-VII.0 Adjustment (G. Palmiotti); 5 - Demonstration - Plot comparisons of participants' results (E. Dupont); 6 - Some very preliminary indications from recent adjustment studies intercomparison (M. Salvatores); 7 - Resonance Region of "5"6Fe for the CIELO Project (L. Leal); 8 - A-priori and a-posteriori covariance data in nuclear cross section adjustments: issues and challenges (G. Palmiotti); 9 - Comments on Covariance Data of JENDL-4.0 and ENDF/B-VII.1 (K

Superconducting technology

International Nuclear Information System (INIS)

2010-01-01

Superconductivity has a long history of about 100 years. Over the past 50 years, progress in superconducting materials has been mainly in metallic superconductors, such as Nb, Nb-Ti and Nb 3 Sn, resulting in the creation of various application fields based on the superconducting technologies. High-T c superconductors, the first of which was discovered in 1986, have been changing the future vision of superconducting technology through the development of new application fields such as power cables. On basis of these trends, future prospects of superconductor technology up to 2040 are discussed. In this article from the viewpoints of material development and the applications of superconducting wires and electronic devices. (author)

Superconductivity

CERN Document Server

Ketterson, John B

2008-01-01

Conceived as the definitive reference in a classic and important field of modern physics, this extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in the field of superconductivity. Leading researchers, including Nobel laureates, describe the state-of-the-art in conventional and unconventional superconductors at a particularly opportune time, as new experimental techniques and field-theoretical methods have emerged. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued intense research into electron-phone based superconductivity. Considerable attention is devoted to high-Tc superconductivity, novel superconductivity, including triplet pairing in the ruthenates, novel superconductors, such as heavy-Fermion metals and organic materials, and also granular superconductors. What’s more, several contributions address superconductors with impurities and nanostructured superconductors. Important new results on...

Superconductivity revisited

CERN Document Server

Dougherty, Ralph

2013-01-01

While the macroscopic phenomenon of superconductivity is well known and in practical use worldwide in many industries, including MRIs in medical diagnostics, the current theoretical paradigm for superconductivity (BCS theory) suffers from a number of limitations, not the least of which is an adequate explanation of high temperature superconductivity. This book reviews the current theory and its limitations and suggests new ideas and approaches in addressing these issues. The central objective of the book is to develop a new, coherent, understandable theory of superconductivity directly based on molecular quantum mechanics.

High field superconducting magnets

Science.gov (United States)

Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

2011-01-01

A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean[W][OA

Science.gov (United States)

Sayama, Takashi; Ono, Eiichiro; Takagi, Kyoko; Takada, Yoshitake; Horikawa, Manabu; Nakamoto, Yumi; Hirose, Aya; Sasama, Hiroko; Ohashi, Mihoko; Hasegawa, Hisakazu; Terakawa, Teruhiko; Kikuchi, Akio; Kato, Shin; Tatsuzaki, Nana; Tsukamoto, Chigen; Ishimoto, Masao

2012-01-01

Triterpene saponins are a diverse group of biologically functional products in plants. Saponins usually are glycosylated, which gives rise to a wide diversity of structures and functions. In the group A saponins of soybean (Glycine max), differences in the terminal sugar species located on the C-22 sugar chain of an aglycone core, soyasapogenol A, were observed to be under genetic control. Further genetic analyses and mapping revealed that the structural diversity of glycosylation was determined by multiple alleles of a single locus, Sg-1, and led to identification of a UDP-sugar–dependent glycosyltransferase gene (Glyma07g38460). Although their sequences are highly similar and both glycosylate the nonacetylated saponin A0-αg, the Sg-1a allele encodes the xylosyltransferase UGT73F4, whereas Sg-1b encodes the glucosyltransferase UGT73F2. Homology models and site-directed mutagenesis analyses showed that Ser-138 in Sg-1a and Gly-138 in Sg-1b proteins are crucial residues for their respective sugar donor specificities. Transgenic complementation tests followed by recombinant enzyme assays in vitro demonstrated that sg-10 is a loss-of-function allele of Sg-1. Considering that the terminal sugar species in the group A saponins are responsible for the strong bitterness and astringent aftertastes of soybean seeds, our findings herein provide useful tools to improve commercial properties of soybean products. PMID:22611180

Molecular characterization of SG33 and Borghi vaccines used against myxomatosis.

Science.gov (United States)

Cavadini, Patrizia; Botti, Giuliana; Barbieri, Ilaria; Lavazza, Antonio; Capucci, Lorenzo

2010-07-26

Myxoma virus is a poxvirus responsible for myxomatosis in European Rabbits (Oryctolagus cuniculus). The entire genome of the myxoma virus has been sequenced, allowing a systemic survey of the functions of a large number of putative pathogenic factors that this virus expresses to subvert the immune and inflammatory pathways of infected rabbit hosts. In Italy, industrial rabbits are mostly vaccinated against myxomatosis using the attenuated myxoma virus strains Borghi or SG33. We have identified genetic markers specific for Borghi or SG33 vaccine strains and established a PCR-based assay that could be used to: (a) rapidly diagnose the presence of myxoma virus in infected organs; (b) discriminate between field strain-infected and vaccinated rabbits and (c) differentiate between Borghi or SG33 vaccine strain. Copyright 2010 Elsevier Ltd. All rights reserved.

Computation of improved tidal parameters at the gravimetric station of Brasimone

Directory of Open Access Journals (Sweden)

P. Baldi

1997-06-01

Full Text Available Since 1991 a GWR superconducting gravimeter has been working in a laboratory at the Brasimone ENEA Research Centre, near Bologna (Italy, in the frame of an experimental program to verify Newton's law over distances of the order of 10-100 m. Owing to the aim of the experiment, the gravimeter was moved to different laboratories in the same area, but from August 1995 to date it has been working continuously in the same laboratory in the frame of the preliminary program of the Global Geodynamics Project. The site, belonging to a building of a dismissed nuclear power plant, is free from noise due to human activities, and is thus highly suitable for recording Earth tides. Starting from a set of gravimetric and atmospheric pressure data of high quality relative to 22 months of observation, we performed the tidal analysis using Eterna 3.2 software in order to compute amplitudes, gravimetric factors and phases of the main waves of the Tamura 1987 catalogue. The accuracy of the method adopted for the calibration of the gravimeter, the values of the principal waves and the result of the computation of atmospheric pressure admittance are described.

Superconductivity in Medicine

Science.gov (United States)

Alonso, Jose R.; Antaya, Timothy A.

2012-01-01

Superconductivity is playing an increasingly important role in advanced medical technologies. Compact superconducting cyclotrons are emerging as powerful tools for external beam therapy with protons and carbon ions, and offer advantages of cost and size reduction in isotope production as well. Superconducting magnets in isocentric gantries reduce their size and weight to practical proportions. In diagnostic imaging, superconducting magnets have been crucial for the successful clinical implementation of magnetic resonance imaging. This article introduces each of those areas and describes the role which superconductivity is playing in them.

Analysis of syringyl and guaiacyl (S/G) ratio in lignin

CSIR Research Space (South Africa)

Spark, A

2006-12-01

Full Text Available the acidolysis products – Validate the new S/G ratio method Why are S/G ratios important? Gives a good indication of the reactivity of the lignin Experimental design Literature Review Establishing Acidolysis conditions Permanganate oxidation Lignin...-method is quick • Permanganate oxidation-method is slow but it is the standard method used at present • Nitrobenzene Oxidation, Pyrolysis, Cupric Oxidation and Thioacidolysis Lignin can be broken down to syringyl and guaiacyl subunits: OCH3 OH OCH3 OH...

SG2NA enhances cancer cell survival by stabilizing DJ-1 and thus activating Akt

Energy Technology Data Exchange (ETDEWEB)

Tanti, Goutam Kumar, E-mail: goutamjnu@hotmail.com; Pandey, Shweta; Goswami, Shyamal K.

2015-08-07

SG2NA in association with striatin and zinedin forms a striatin family of WD-40 repeat proteins. This family of proteins functions as scaffold in different signal transduction pathways. They also act as a regulatory subunit of protein phosphatase 2A. We have shown that SG2NA which evolved first in the metazoan evolution among the striatin family members expresses different isoforms generated out of alternative splicing. We have also shown that SG2NA protects cells from oxidative stress by recruiting DJ-1 and Akt to mitochondria and membrane in the post-mitotic neuronal cells. DJ-1 is both cancer and Parkinson's disease related protein. In the present study we have shown that SG2NA protects DJ-1 from proteasomal degradation in cancer cells. Hence, downregulation of SG2NA reduces DJ-1/Akt colocalization in cancer cells resulting in the reduction of anchorage dependent and independent growth. Thus SG2NA enhances cancer cell survival. Reactive oxygen species enhances SG2NA, DJ-1 and Akt trimerization. Removal of the reactive oxygen species by N-acetyl-cysteine thus reduces cancer cell growth. - Highlights: • Reactive oxygen species (ROS) play potential role in cancer cell proliferation. • It enhances the association between DJ-1 and Akt mediated by SG2NA. • In cancer cells SG2NA stabilizes DJ-1 by inhibiting it from proteosomal degradation. • DJ-1 then activates Akt and cancer cells get their property of enhanced proliferation by sustained activation of Akt. • Further study on this field could lead to new target for cancer therapy.

SG2NA enhances cancer cell survival by stabilizing DJ-1 and thus activating Akt

International Nuclear Information System (INIS)

Tanti, Goutam Kumar; Pandey, Shweta; Goswami, Shyamal K.

2015-01-01

SG2NA in association with striatin and zinedin forms a striatin family of WD-40 repeat proteins. This family of proteins functions as scaffold in different signal transduction pathways. They also act as a regulatory subunit of protein phosphatase 2A. We have shown that SG2NA which evolved first in the metazoan evolution among the striatin family members expresses different isoforms generated out of alternative splicing. We have also shown that SG2NA protects cells from oxidative stress by recruiting DJ-1 and Akt to mitochondria and membrane in the post-mitotic neuronal cells. DJ-1 is both cancer and Parkinson's disease related protein. In the present study we have shown that SG2NA protects DJ-1 from proteasomal degradation in cancer cells. Hence, downregulation of SG2NA reduces DJ-1/Akt colocalization in cancer cells resulting in the reduction of anchorage dependent and independent growth. Thus SG2NA enhances cancer cell survival. Reactive oxygen species enhances SG2NA, DJ-1 and Akt trimerization. Removal of the reactive oxygen species by N-acetyl-cysteine thus reduces cancer cell growth. - Highlights: • Reactive oxygen species (ROS) play potential role in cancer cell proliferation. • It enhances the association between DJ-1 and Akt mediated by SG2NA. • In cancer cells SG2NA stabilizes DJ-1 by inhibiting it from proteosomal degradation. • DJ-1 then activates Akt and cancer cells get their property of enhanced proliferation by sustained activation of Akt. • Further study on this field could lead to new target for cancer therapy

Superconductivity in technology

International Nuclear Information System (INIS)

Komarek, P.

1976-01-01

Physics, especially high energy physics and solid state physics was the first area in which superconducting magnets were used but in the long run, the most extensive application of superconductivity will probably be in energy technology. Superconducting power transmission cables, magnets for energy conversion in superconducting electrical machines, MHD-generators and fusion reactors and magnets for energy storage are being investigated. Magnets for fusion reactors will have particularly large physical dimensions, which means that much development effort is still needed, for there is no economic alternative. Superconducting surfaces in radio frequency cavities can give Q-values up to a factor of 10 6 higher than those of conventional resonators. Particle accelerators are the important application. And for telecommunication, simple coaxial superconducting radio frequency cables seem promising. The tunnel effect in superconducting junctions is now being developed commercially for sensitive magnetometers and may soon possibly feature in the memory cells of computer devices. Hence superconductivity can play an important role in the technological world, solving physical and technological problems and showing economic advantages as compared with possible conventional techniques, bearing also in mind the importance of reliability and safety. (author)

Understanding and application of superconducting materials

International Nuclear Information System (INIS)

Moon, Byeong Mu; Lee, Chun Heung

1997-02-01

This book deals with superconducting materials, which contains from basic theory to application of superconducting materials. The contents of this book are mystery of superconducting materials, properties of superconducting materials, thermodynamics of superconducting materials, theoretical background of superconducting materials, tunnelling and quantum interference, classification and properties of superconducting materials, high temperature superconducting materials, production and analysis of superconducting materials and application of superconducting materials.

Submicron superconducting structures

International Nuclear Information System (INIS)

Golovashkin, A.I.; Lykov, A.N.

1986-01-01

An overview of works concerning superconducting structures of submicron dimensions and a system of such structures is given. It is noted that usage of the above structures in superconducting microelectronics permits, first, to increase the element packing density, to decrease the signal transmission time, capacity, power dissipated in high-frequency applications. Secondly, negligible coherence length in transition metals, their alloys and high-temperature compounds also restrict the dimensions of superconducting weak couplings when the 'classical' Josephson effect is displayed. The most effective methods for production of submicron superconducting structures are the following: lithography, double scribering. Recently the systems of superconducting submicron elements are extensively studied. It is shown that such systems can be phased by magnetic field

Molecular characterization of a proteolysis-resistant lipase from Bacillus pumilus SG2

Directory of Open Access Journals (Sweden)

R. Sangeetha

2014-06-01

Full Text Available Proteolysis-resistant lipases can be well exploited by industrial processes which employ both lipase and protease as biocatalysts. A proteolysis resistant lipase from Bacillus pumilus SG2 was isolated, purified and characterized earlier. The lipase was resistant to native and commercial proteases. In the present work, we have characterized the lip gene which encodes the proteolysis-resistant lipase from Bacillus pumilus SG2. The parameters and structural details of lipase were analysed. The lip gene consisted of 650 bp. The experimental molecular weight of SG2 lipase was nearly double that of its theoretical molecular weight, thus suggesting the existence of the functional lipase as a covalent dimer. The proteolytic cleavage sites of the lipase would have been made inaccessible by dimerisation, thus rendering the lipase resistant to protease.

Academic training: Applied superconductivity

CERN Multimedia

2007-01-01

LECTURE SERIES 17, 18, 19 January from 11.00 to 12.00 hrs Council Room, Bldg 503 Applied Superconductivity : Theory, superconducting Materials and applications E. PALMIERI/INFN, Padova, Italy When hearing about persistent currents recirculating for several years in a superconducting loop without any appreciable decay, one realizes that we are dealing with a phenomenon which in nature is the closest known to the perpetual motion. Zero resistivity and perfect diamagnetism in Mercury at 4.2 K, the breakthrough during 75 years of several hundreds of superconducting materials, the revolution of the "liquid Nitrogen superconductivity"; the discovery of still a binary compound becoming superconducting at 40 K and the subsequent re-exploration of the already known superconducting materials: Nature discloses drop by drop its intimate secrets and nobody can exclude that the last final surprise must still come. After an overview of phenomenology and basic theory of superconductivity, the lectures for this a...

The state of superconductivity

International Nuclear Information System (INIS)

Clark, T.D.

1981-01-01

The present status of applications based on the phenomena of superconductivity are reviewed. Superconducting materials, large scale applications, the Josephson effect and its applications, and superconductivity in instrumentation, are considered. The influence that superconductivity has had on modern theories of elementary particles, such as gauge symmetry breaking, is discussed. (U.K.)

Superconductivity - applications

International Nuclear Information System (INIS)

The paper deals with the following subjects: 1) Electronics and high-frequency technology, 2) Superconductors for energy technology, 3) Superconducting magnets and their applications, 4) Electric machinery, 5) Superconducting cables. (WBU) [de

Basic Study of Superconductive Actuator

OpenAIRE

涌井, 和也; 荻原, 宏康

2000-01-01

There are two kinds of electromagnetic propulsion ships : a superconductive electromagnetic propulsion ship and a superconductive electricity propulsion ship. A superconductive electromagnetic propulsion ship uses the electromagnetic force (Lorenz force) by the interaction between a magnetic field and a electric current. On the other hand, a superconductive electricity propulsion ship uses screws driven by a superconductive motor. A superconductive propulsion ship technique has the merits of ...

100 years of superconductivity

CERN Document Server

Rogalla, Horst

2011-01-01

Even a hundred years after its discovery, superconductivity continues to bring us new surprises, from superconducting magnets used in MRI to quantum detectors in electronics. 100 Years of Superconductivity presents a comprehensive collection of topics on nearly all the subdisciplines of superconductivity. Tracing the historical developments in superconductivity, the book includes contributions from many pioneers who are responsible for important steps forward in the field.The text first discusses interesting stories of the discovery and gradual progress of theory and experimentation. Emphasizi

Superconducting current in a bisoliton superconductivity model

International Nuclear Information System (INIS)

Ermakov, V.N.; Kruchinin, S.P.; Ponezha, E.A.

1991-01-01

It is shown that the transition into a superconducting state with the current which is described by a bisoliton superconductivity model is accompanied by the deformation of the spectrum of one-particle states of the current carriers. The deformation value is proportional to the conducting current force. The residuaby resistance in such state is absent

Coexistence of magnetism and superconductivity in the hole doped FeAs-based superconducting compound

International Nuclear Information System (INIS)

Lu, T.P.; Wu, C.C.; Chou, W.H.; Lan, M.D.

2010-01-01

The magnetic and superconducting properties of the Sm-doped FeAs-based superconducting compound were investigated under wide ranges of temperature and magnetic field. After the systematical magnetic ion substitution, the superconducting transition temperature decreases with increasing magnetic moment. The hysteresis loop of the La 0.87-x Sm x Sr 0.13 FeAsO sample shows a superconducting hysteresis and a paramagnetic background signal. The paramagnetic signal is mainly attributed to the Sm moments. The experiment demonstrates that the coexistence of magnetism and superconductivity in the hole doped FeAs-based superconducting compounds is possible. Unlike the electron doped FeAs-based superconducting compounds SmFeAsOF, the hole doped superconductivity is degraded by the substitution of La by Sm. The hole-doped and electron-doped sides are not symmetric.

Information Flow Analysis for Human-System Interaction in the SG Level Control

International Nuclear Information System (INIS)

Kim, Jong Hyun; Shin, Yeong Cheol

2008-01-01

Interaction between automatic control and operators is one of main issues in the application of automation technology. Inappropriate information from automatic control systems causes unexpected problems in human-automation collaboration. Poor information becomes critical, especially when the operator takes over the control from an automation system. Operators cannot properly handle the situation transferred from the automatic mode because of inadequate situation awareness, if the operator is out-of-the loop and the automatic control system fails. Some cases of unplanned reactor trips during the transition between the manual mode and the automatic mode are reported in nuclear power plants (NPPs). Among unplanned reactor trips since 2002, two cases were partially caused by automation-related failures of steam generator (SG) level control. This paper conducts information flow analysis to identify information and control requirement for human-system interaction of SG level control. At first, this paper identifies the level of automation in SG level control systems and then function allocation between system control and human operators. Then information flow analysis for monitoring and transition of automation is performed by adapting job process chart. Information and control requirements will be useful as an input for the human-system interface (HSI) design of SG level control

Estimation of S/G ratio in woods using 1064 nm FT-Raman spectroscopy

Science.gov (United States)

Umesh P. Agarwal; Sally A. Ralph; Dharshana Padmakshan; Sarah Liu; Steven D. Karlen; Cliff Foster; John Ralph

2015-01-01

Two simple methods based on the 370 cm-1 Raman band intensity were developed for estimation of syringyl-to-guaiacyl (S/G) ratio in woods. The methods, in principle, are representative of the whole cell wall lignin and not just the portion of lignin that gets cleaved to release monomers, for example, during certain S/G chemical analyses. As such,...

Novel peptide marker corresponding to salivary protein gSG6 potentially identifies exposure to Anopheles bites.

Directory of Open Access Journals (Sweden)

Anne Poinsignon

2008-06-01

Full Text Available In order to improve malaria control, and under the aegis of WHO recommendations, many efforts are being devoted to developing new tools for identifying geographic areas with high risk of parasite transmission. Evaluation of the human antibody response to arthropod salivary proteins could be an epidemiological indicator of exposure to vector bites, and therefore to risk of pathogen transmission. In the case of malaria, which is transmitted only by anopheline mosquitoes, maximal specificity could be achieved through identification of immunogenic proteins specific to the Anopheles genus. The objective of the present study was to determine whether the IgG response to the Anopheles gambiae gSG6 protein, from its recombinant form to derived synthetic peptides, could be an immunological marker of exposure specific to Anopheles gambiae bites.Specific IgG antibodies to recombinant gSG6 protein were observed in children living in a Senegalese area exposed to malaria. With the objective of optimizing Anopheles specificity and reproducibility, we designed five gSG6-based peptide sequences using a bioinformatic approach, taking into consideration i their potential antigenic properties and ii the absence of cross-reactivity with protein sequences of other arthropods/organisms. The specific anti-peptide IgG antibody response was evaluated in exposed children. The five gSG6 peptides showed differing antigenic properties, with gSG6-P1 and gSG6-P2 exhibiting the highest antigenicity. However, a significant increase in the specific IgG response during the rainy season and a positive association between the IgG level and the level of exposure to Anopheles gambiae bites was significant only for gSG6-P1.This step-by-step approach suggests that gSG6-P1 could be an optimal candidate marker for evaluating exposure to Anopheles gambiae bites. This marker could be employed as a geographic indicator, like remote sensing techniques, for mapping the risk of malaria. It could

High-current applications of superconductivity

International Nuclear Information System (INIS)

Komarek, P.

1995-01-01

The following topics were dealt with: superconducting materials, design principles of superconducting magnets, magnets for research and engineering, superconductivity for power engineering, superconductivity in nuclear fusion technology, economical considerations

Laser activated superconducting switch

International Nuclear Information System (INIS)

Wolf, A.A.

1976-01-01

A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

Superconducting linac

International Nuclear Information System (INIS)

Bollinger, L.M.; Shepard, K.W.; Wangler, T.P.

1978-01-01

This project has two goals: to design, build, and test a small superconducting linac to serve as an energy booster for heavy ions from an FN tandem electrostatic accelerator, and to investigate various aspects of superconducting rf technology. The main design features of the booster are described, a status report on various components (resonators, rf control system, linac control system, cryostats, buncher) is given, and plans for the near future are outlined. Investigations of superconducting-linac technology concern studies on materials and fabrication techniques, resonator diagnostic techniques, rf-phase control, beam dynamics computer programs, asymmetry in accelerating field, and surface-treatment techniques. The overall layout of the to-be-proposed ATLAS, the Argonne Tandem-Linac Accelerator System, is shown; the ATLAS would use superconducting technology to produce beams of 5 to 25 MeV/A. 6 figures

Superconductivity and electron microscopy

International Nuclear Information System (INIS)

Hawkes, P.W.; Valdre, U.

1977-01-01

In this review article, two aspects of the role of superconductivity in electron microscopy are examined: (i) the development of superconducting devices (mainly lenses) and their incorporation in electron microscopes; (ii) the development of electron microscope techniques for studying fundamental and technological problems associated with superconductivity. The first part opens with a brief account of the relevant properties of conventional lenses, after which the various types of superconducting lenses are described and their properties compared. The relative merits and inconveniences of superconducting and conventional lenses are examined, particular attention being paid to the spherical and chromatic aberration coefficients at accelerating voltages above a megavolt. This part closes with a survey of the various microscope designs that have been built or proposed, incorporating superconducting components. In the second part, some methods that have been or might be used in the study of superconductivity in the electron microscope are described. A brief account of the types of application for which they are suitable is given. (author)

Superconductivity in transition metals.

Science.gov (United States)

Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

2015-03-13

A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Gravity sensing using Very Long Baseline Atom Interferometry

Science.gov (United States)

Schlippert, D.; Wodey, E.; Meiners, C.; Tell, D.; Schubert, C.; Ertmer, W.; Rasel, E. M.

2017-12-01

Very Long Baseline Atom Interferometry (VLBAI) has applications in high-accuracy absolute gravimetry, gravity-gradiometry, and for tests of fundamental physics. Thanks to the quadratic scaling of the phase shift with increasing free evolution time, extending the baseline of atomic gravimeters from tens of centimeters to meters puts resolutions of 10-13g and beyond in reach.We present the design and progress of key elements of the VLBAI-test stand: a dual-species source of Rb and Yb, a high-performance two-layer magnetic shield, and an active vibration isolation system allowing for unprecedented stability of the mirror acting as an inertial reference. We envisage a vibration-limited short-term sensitivity to gravitational acceleration of 1x10-8 m/s-2Hz-1/2 and up to a factor of 25 improvement when including additional correlation with a broadband seismometer. Here, the supreme long-term stability of atomic gravity sensors opens the route towards competition with superconducting gravimeters. The operation of VLBAI as a differential dual-species gravimeter using ultracold mixtures of Yb and Rb atoms enables quantum tests of the universality of free fall (UFF) at an unprecedented level of <10-13, potentially surpassing the best experiments to date.

Linear arrangement of metallic and superconducting defects in a thin superconducting sample

International Nuclear Information System (INIS)

Barba-Ortega, J.; Sardella, Edson; Albino Aguiar, J.

2013-01-01

Highlights: • We study the influence of superconducting and metallic defects on the vortex configurations in a thin mesoscopic disk. • We found that the vortex–defect interaction leads to interesting vortex configurations. • The first vortex entry is always (never) found sitting on the metallic (superconducting) defect position. -- Abstract: The vortex matter in a superconducting disk with a linear configuration of metallic and superconducting defects is studied. Effects associated to the pinning (anti-pinning) force of the metallic (superconducting) defect on the vortex configuration and on the thermodynamic critical fields are analyzed in the framework of the Ginzburg Landau theory. We calculate the loop of the magnetization, vorticity and free energy curves as a function of the magnetic field for a thin disk. Due to vortex–defect attraction for a metallic defect (repulsion for a superconducting defect), the vortices always (never) are found to be sitting on the defect position

Superconducting state mechanisms and properties

CERN Document Server

Kresin, Vladimir Z; Wolf, Stuart A

2014-01-01

'Superconducting State' provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, and plasmons). A very complete description is given of the electron-phonon mechanism responsible for superconductivity in the majority of superconducting systems, and the history of its development, as well as a detailed description of the key experimental techniques used to study the superconducting state and determine the mechanisms. In addition, there are chapters describing the discovery and properties of the key superconducting compounds that are of the most interest for science, and applications including a special chapter on the cuprate superconductors. It provides detailed treatments of some very novel aspects of superconductivity, including multiple bands (gaps), the "pseudogap" state, novel isotope effects beyond BCS, and induced superconductivity.

The Hydrogen Detection Technique for SG Protection System

International Nuclear Information System (INIS)

Lv Mingyu; Pei Zhiyong; Yu Huajin

2015-01-01

SG that is pressure boundary between secondary loop and triple loop is the key equipment of fast reactor, in which heat in secondary loop is transferred to water or steam in triple loop. According to data from IAEA, SG is the highest failure rate equipment in fast reactor, especially because of failure of heat transfer tube. In order to monitor failure of heat transfer tube, Fast Reactor Engineering Department develops diffusion type hydrogen detection system, which is used to detect sodium-water reaction in time. This paper firstly introduces experimental research scheme and results of this hydrogen detection technique; Subsequently, it is described that how this technique can be engineering realized in CEFR; Moreover, through developing a series of calibration tests and hydrogen injection tests, it is obtained that sensitivity, response time and calibration curse for hydrogen detection system of CEFR. (author)

Enhanced superconductivity of fullerenes

Energy Technology Data Exchange (ETDEWEB)

Washington, II, Aaron L.; Teprovich, Joseph A.; Zidan, Ragaiy

2017-06-20

Methods for enhancing characteristics of superconductive fullerenes and devices incorporating the fullerenes are disclosed. Enhancements can include increase in the critical transition temperature at a constant magnetic field; the existence of a superconducting hysteresis over a changing magnetic field; a decrease in the stabilizing magnetic field required for the onset of superconductivity; and/or an increase in the stability of superconductivity over a large magnetic field. The enhancements can be brought about by transmitting electromagnetic radiation to the superconductive fullerene such that the electromagnetic radiation impinges on the fullerene with an energy that is greater than the band gap of the fullerene.

Study on Temperature Control System Based on SG3525

Science.gov (United States)

Cheng, Cong; Zhu, Yifeng; Wu, Junfeng

2017-12-01

In this paper, it uses the way of dry bath temperature to heat the microfluidic chip directly by the heating plate and the liquid sample in microfluidic chip is heated through thermal conductivity, thus the liquid sample will maintain at target temperature. In order to improve the reliability of the whole machine, a temperature control system based on SG3525 is designed.SG3525 is the core of the system which uses PWM wave produced by itself to drive power tube to heat the heating plate. The bridge circuit consisted of thermistor and PID regulation ensure that the temperature can be controlled at 37 °C with a correctness of ± 0.2 °C and a fluctuation of ± 0.1 °C.

Hole superconductivity

International Nuclear Information System (INIS)

Hirsch, J.E.; Marsiglio, F.

1989-01-01

The authors review recent work on a mechanism proposed to explain high T c superconductivity in oxides as well as superconductivity of conventional materials. It is based on pairing of hole carriers through their direct Coulomb interaction, and gives rise to superconductivity because of the momentum dependence of the repulsive interaction in the solid state environment. In the regime of parameters appropriate for high T c oxides this mechanism leads to characteristic signatures that should be experimentally verifiable. In the regime of conventional superconductors most of these signatures become unobservable, but the characteristic dependence of T c on band filling survives. New features discussed her include the demonstration that superconductivity can result from repulsive interactions even if the gap function does not change sign and the inclusion of a self-energy correction to the hole propagator that reduces the range of band filling where T c is not zero

Emergent Higgsless Superconductivity

Directory of Open Access Journals (Sweden)

Cristina Diamantini M.

2017-01-01

Full Text Available We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalizable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D-1-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact lowenergy effective BF theories. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2 and the topological order (4 are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D thi! s type of superconductivity is explicitly realized as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.

Superconducting Fullerene Nanowhiskers

Directory of Open Access Journals (Sweden)

Yoshihiko Takano

2012-04-01

Full Text Available We synthesized superconducting fullerene nanowhiskers (C₆₀NWs by potassium (K intercalation. They showed large superconducting volume fractions, as high as 80%. The superconducting transition temperature at 17 K was independent of the K content (x in the range between 1.6 and 6.0 in K-doped C₆₀ nanowhiskers (K_xC₆₀NWs, while the superconducting volume fractions changed with x. The highest shielding fraction of a full shielding volume was observed in the material of K_3.3C₆₀NW by heating at 200 °C. On the other hand, that of a K-doped fullerene (K-C₆₀ crystal was less than 1%. We report the superconducting behaviors of our newly synthesized K_xC₆₀NWs in comparison to those of K_xC₆₀ crystals, which show superconductivity at 19 K in K₃C₆₀. The lattice structures are also discussed, based on the x-ray diffraction (XRD analyses.

Optimized paired-sgRNA/Cas9 cloning and expression cassette triggers high-efficiency multiplex genome editing in kiwifruit.

Science.gov (United States)

Wang, Zupeng; Wang, Shuaibin; Li, Dawei; Zhang, Qiong; Li, Li; Zhong, Caihong; Liu, Yifei; Huang, Hongwen

2018-01-13

Kiwifruit is an important fruit crop; however, technologies for its functional genomic and molecular improvement are limited. The clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system has been successfully applied to genetic improvement in many crops, but its editing capability is variable depending on the different combinations of the synthetic guide RNA (sgRNA) and Cas9 protein expression devices. Optimizing conditions for its use within a particular species is therefore needed to achieve highly efficient genome editing. In this study, we developed a new cloning strategy for generating paired-sgRNA/Cas9 vectors containing four sgRNAs targeting the kiwifruit phytoene desaturase gene (AcPDS). Comparing to the previous method of paired-sgRNA cloning, our strategy only requires the synthesis of two gRNA-containing primers which largely reduces the cost. We further compared efficiencies of paired-sgRNA/Cas9 vectors containing different sgRNA expression devices, including both the polycistronic tRNA-sgRNA cassette (PTG) and the traditional CRISPR expression cassette. We found the mutagenesis frequency of the PTG/Cas9 system was 10-fold higher than that of the CRISPR/Cas9 system, coinciding with the relative expressions of sgRNAs in two different expression cassettes. In particular, we identified large chromosomal fragment deletions induced by the paired-sgRNAs of the PTG/Cas9 system. Finally, as expected, we found both systems can successfully induce the albino phenotype of kiwifruit plantlets regenerated from the G418-resistance callus lines. We conclude that the PTG/Cas9 system is a more powerful system than the traditional CRISPR/Cas9 system for kiwifruit genome editing, which provides valuable clues for optimizing CRISPR/Cas9 editing system in other plants. © 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons

Experimental and numerical study of deposit formation in secondary side SG TSP by electrokinetic approach

International Nuclear Information System (INIS)

Guillodo, Michael; Foucault, Marc; Ryckelynck, Natacha; Chahma, Farah; Guingo, Mathieu; Mansour, Carine; Alos-Ramos, Olga; Corredera, Geraldine

2012-09-01

Corrosion products deposit formation observed in PWR steam generators (SGs) - related to SG free span fouling and SG clogging - is now reported since several years. SG clogging is a localized phenomenon observed between the leading edge of the Tube Support Plate (TSP) and SG tubing materials. Based on visual inspections, it was found that the gaps between SG tubing material and TSP at the lower part of the broached holes were getting progressively blocked. Therefore, for safe operation, most affected PWRs had to be operated at reduced power. TSP blockage was mainly observed for low-pH water chemistry conditioning, which directly depends on the operating water chemistry. The TSP blockage mechanism is complex due to the localized conditions in which flow pattern change, chemistry and electrochemical conditions are not well understood. Electrokinetic considerations could be pointed out to explain the coupling of chemistry, materials and thermohydraulic (T/H) conditions. In this frame AREVA and EDF have launched a long-term R and D program in order to understand the mechanisms driving the formation of SG clogging. This study based on parametric laboratory tests aims to assess the role of secondary water chemistry, material and T/H conditions on deposit formation. The experimental approach focused on electrokinetic measurements of metallic substrates and on the assessment of oxidation properties of materials in secondary side chemistry. An overall analysis of recent results is presented to address SG deposit formation in secondary water chemistry for various conditioning amines - morpholine, ethanolamine and dimethylamine. To complete the study, the experimental results have been correlated to CFD simulations of particle deposition, by means of stochastic Lagrangian models. These calculations have in particular reproduced correctly the location of the most important particle deposit (the leading edge of the test tube), and have stressed the influence of the

Multi-frequencies ECT algorithms to remove sodium noise in ISI of ferromagnetic SG tubes of FBR

International Nuclear Information System (INIS)

Mihalache, Ovidiu

2012-01-01

The paper presents developments and application of multi-frequency eddy current to be used during In-Service Inspection (ISI) of ferromagnetic steam generator (SG) tubes of Fast Breeder Reactors (FBR). Signal enhancement by means of multi-frequency ECT techniques are validated through 3D simulations of both signals and noise due to sodium forms around SG tube or SP. The purpose of such algorithms is to remove from ECT signal the electromagnetic noise resulting from sodium accumulated outside of SG tubes after SG vessel draining. Finite element method (FEM) simulations are used to analyse different sodium build-up scenarios observed experimentally, and to determine optimal multi-frequency ECT algorithms to suppress the most efficiently sodium noise. Also a new 'window multi-frequency' algorithm is applied and validated using 3-dimensional FEM simulations of SP and sodium forms. (author)

Superconducting quantum electronics

International Nuclear Information System (INIS)

Kose, V.

1989-01-01

This book reviews recent accomplishments, presents new results and discusses possible future developments of superconducting quantum electronics and high T c superconductivity. The three main parts of the book deal with fundamentals, sensitive detectors, and precision metrology. New results reported include: correct equivalent circuits modelling superconducting electronic devices; exact solution of the Mattis-Bardeen equations describing various experiments for thin films; complete theoretical description and experimental results for a new broad band spectrum analyzer; a new Josephson junction potentiometer allowing tracing of unknown voltage ratios back to well-known frequency ratios; and fast superconducting SQUID shift registers enabling the production of calculable noise power spectra in the microwave region

Learnings from investigations on SG divider plates: Coupling field characterizations with numerical mechanical simulation

International Nuclear Information System (INIS)

Rossillon, F.; Depradeux, L.; Miloudi, S.; Deforge, D.; Lemaire, E.; Massoud, J.P.

2014-01-01

Nickel based alloys stress corrosion cracking (SCC) has been a major concern for the nuclear power plant utilities since the 1970s. Since 2002, SCC indications have been found on steam generator (SG) divider plates made of alloy 600 on French PWRs (pressurized water reactors) 900 MWe units. Although integrity is not questioned, many studies have been conducted to deepen understanding of the phenomenon. Among numerous studies to investigate the SCC damage phenomena, advanced mechanical analysis has been performed to improve the knowledge of the in-service loadings of the SG 900 MWe partition stub and divider plate. Manufacturing steps are taken into account, such as welding and the first hydro-test, to have a more precise description of the mechanical states in the vicinity of the welds where SCC is likely to occur. Recently, EDF hot laboratories made destructive examinations of a decommissioned SG. To fulfil the analyses computations have been carried out on the dedicated configuration. A 3D FE model, including the simulation of the welding and hydro-test, has been set up. Comparisons with experimental investigations on the divider plate of decommissioned SG have shown a good agreement between experimental and numerical results. These results emphasize the redistribution of weld residual stresses after the first hydro-test, and the effect of hydro-testing on the plastic deformation of the stub only in some specific cases of 900 MWe SG

Learnings from investigations on SG divider plates: Coupling field characterizations with numerical mechanical simulation

Energy Technology Data Exchange (ETDEWEB)

Rossillon, F., E-mail: frederique.rossillon@edf.fr [EDF SEPTEN, 12-14 Avenue Dutrievoz, Villeurbanne (France); Depradeux, L. [EC2-MS, 66 Bd Niels Bohr, Villeurbanne (France); Miloudi, S. [EDF CEIDRE, CNPE de Chinon, Avoine (France); Deforge, D. [EDF CEIDRE, 2 Rue Ampère, Saint Denis (France); Lemaire, E. [EDF UNIE, Cap Ampère, Saint Denis (France); Massoud, J.P. [EDF SEPTEN, 12-14 Avenue Dutrievoz, Villeurbanne (France)

2014-04-01

Nickel based alloys stress corrosion cracking (SCC) has been a major concern for the nuclear power plant utilities since the 1970s. Since 2002, SCC indications have been found on steam generator (SG) divider plates made of alloy 600 on French PWRs (pressurized water reactors) 900 MWe units. Although integrity is not questioned, many studies have been conducted to deepen understanding of the phenomenon. Among numerous studies to investigate the SCC damage phenomena, advanced mechanical analysis has been performed to improve the knowledge of the in-service loadings of the SG 900 MWe partition stub and divider plate. Manufacturing steps are taken into account, such as welding and the first hydro-test, to have a more precise description of the mechanical states in the vicinity of the welds where SCC is likely to occur. Recently, EDF hot laboratories made destructive examinations of a decommissioned SG. To fulfil the analyses computations have been carried out on the dedicated configuration. A 3D FE model, including the simulation of the welding and hydro-test, has been set up. Comparisons with experimental investigations on the divider plate of decommissioned SG have shown a good agreement between experimental and numerical results. These results emphasize the redistribution of weld residual stresses after the first hydro-test, and the effect of hydro-testing on the plastic deformation of the stub only in some specific cases of 900 MWe SG.

Superconductivity in graphite intercalation compounds

International Nuclear Information System (INIS)

Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P.M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

2015-01-01

Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC 6 and YbC 6 in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition

Superconductivity in graphite intercalation compounds

Energy Technology Data Exchange (ETDEWEB)

Smith, Robert P. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Weller, Thomas E.; Howard, Christopher A. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Dean, Mark P.M. [Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Rahnejat, Kaveh C. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Saxena, Siddharth S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Ellerby, Mark, E-mail: mark.ellerby@ucl.ac.uk [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom)

2015-07-15

Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC{sub 6} and YbC{sub 6} in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

Development of a light weighted mobile robot for SG tube inspection in NPP

International Nuclear Information System (INIS)

Seo, Yong Chil; Jeong, Kyung Min; Shin, Hochul; Gweng, Jung Ju; Lee, Sung Uk; Jeong, Seung Ho; Choi, Young Soo; Kim, Seung Ho; Shin, Chun Sup; Park, Ki Tae

2012-01-01

Steam generators (SG) are among the most critical components of pressurized water Nuclear Power Plants (NPP). SG tubes must provide a reliable pressure boundary between the primary and secondary cooling water, because any leakage from tube defects could result in the release of radioactivity to the environment. Thus degradations of steam generators tubes should be monitored and inspected periodically under nuclear regulation. In service inspections of SG tubes are carried out using eddy current test (ECT) and the defected tubes are usually plugged. Because the radioactivity in the internal SG chambers limits free access of human workers, remote manipulators are required. In South Korea, Manipulators such as the Zet ec SM series and the Westinghouse ROSA series have bee used. Such manipulators are rigidly mounted to man ways or tube sheets of SG. Confusions of the inspected tubes may occur from deflection of the manipulators. To reduce the deflections of the manipulators for covering the large working areas of tube sheets, sufficient rigidity is required and that leads to an increase of the weight. Such weight increase results in some difficulties for handling and more radiation exposure of human workers. Recently light weighed mobile robots have been introduced by Westinghouse and Zet ec. The robots can move keeping in contact with the tube sheets using devices which are commonly called cam locks. They are easier to handle and provide no confusion for the position of the inspected tubes. But when the clamping forces are loosed accidentally, they can be fall down and light repair works can be performed. This paper provides the design results for a lightweight mobile robot which is being developed in cooperation of our institutes

Development of a light weighted mobile robot for SG tube inspection in NPP

Energy Technology Data Exchange (ETDEWEB)

Seo, Yong Chil; Jeong, Kyung Min; Shin, Hochul; Gweng, Jung Ju; Lee, Sung Uk; Jeong, Seung Ho; Choi, Young Soo; Kim, Seung Ho [KAERI, Daejeon (Korea, Republic of); Shin, Chun Sup; Park, Ki Tae [Korea Plant Service and Engineering, Busan (Korea, Republic of)

2012-10-15

Steam generators (SG) are among the most critical components of pressurized water Nuclear Power Plants (NPP). SG tubes must provide a reliable pressure boundary between the primary and secondary cooling water, because any leakage from tube defects could result in the release of radioactivity to the environment. Thus degradations of steam generators tubes should be monitored and inspected periodically under nuclear regulation. In service inspections of SG tubes are carried out using eddy current test (ECT) and the defected tubes are usually plugged. Because the radioactivity in the internal SG chambers limits free access of human workers, remote manipulators are required. In South Korea, Manipulators such as the Zet ec SM series and the Westinghouse ROSA series have bee used. Such manipulators are rigidly mounted to man ways or tube sheets of SG. Confusions of the inspected tubes may occur from deflection of the manipulators. To reduce the deflections of the manipulators for covering the large working areas of tube sheets, sufficient rigidity is required and that leads to an increase of the weight. Such weight increase results in some difficulties for handling and more radiation exposure of human workers. Recently light weighed mobile robots have been introduced by Westinghouse and Zet ec. The robots can move keeping in contact with the tube sheets using devices which are commonly called cam locks. They are easier to handle and provide no confusion for the position of the inspected tubes. But when the clamping forces are loosed accidentally, they can be fall down and light repair works can be performed. This paper provides the design results for a lightweight mobile robot which is being developed in cooperation of our institutes.

Modern high-temperature superconductivity

International Nuclear Information System (INIS)

Ching Wu Chu

1988-01-01

Ever since the discovery of superconductivity in 1911, its unusual scientific challenge and great technological potential have been recognized. For the past three-quarters of a century, superconductivity has done well on the science front. This is because sueprconductivity is interesting not only just in its own right but also in its ability to act as a probe to many exciting nonsuperconducting phenomena. For instance, it has continued to provide bases for vigorous activities in condensed matter science. Among the more recent examples are heavy-fermion systems and organic superconductors. During this same period of time, superconductivity has also performed admirably in the applied area. Many ideas have been conceived and tested, making use of the unique characteristics of superconductivity - zero resistivity, quantum interference phenomena, and the Meissner effect. In fact, it was not until late January 1987 that it became possible to achieve superconductivity with the mere use of liquid nitrogen - which is plentiful, cheap, efficient, and easy to handle - following the discovery of supercondictivity above 90 K in Y-Ba-Cu-O, the first genuine quaternary superconductor. Superconductivity above 90 K poses scientific and technological challenges not previously encountered: no existing theories can adequately describe superconductivity above 40 K and no known techniques can economically process the materials for full-scale applications. In this paper, therefore, the author recalls a few events leading to the discovery of the new class of quaternary compounds with a superconducting transition temperature T c in the 90 K range, describes the current experimental status of high-temperature superconductivity and, finally, discusses the prospect of very-high-temperature superconductivity, i.e., with a T c substantially higher than 100 K. 97 refs., 7 figs

Methodology for failure assessment of SMART SG tube with once-through helical-coiled type

International Nuclear Information System (INIS)

Kim, Young Jin; Choi, Shin Beom; Cho, Doo Ho; Chang, Yoon Suk

2010-09-01

In this research project, existing integrity evaluation method for SMART steam generator tube with crack-like flaw was reviewed to determine subject analysis model and investigate possibility of failure under crack closure behavior. Furthermore, failure pressure estimation was proposed for SMART steam generator tubes containing wear-type defects. For each subject, the following issues are addressed: 1. Determination of subject analysis model for SMART SG tube contaning crack-like flaw 2. Applicability review on existing integrity evaluation method and investigation of failure possibility for SMART SG tube containing crack-like flaw 3. Development of failure pressure estimation model for SMART SG tube with wear type defect It is anticipated that if the technologies developed in this study are applied, structural integrity can be estimated accurately

Inhomogeneous superconductivity in a ferromagnet

International Nuclear Information System (INIS)

Kontos, T.; Aprili, M.; Lesueur, J.; Genet, F.; Boursier, R.; Grison, X.

2003-01-01

We have studied a new superconducting state where the condensate wave function resulting from conventional pairing, is modified by an exchange field. Superconductivity is induced into a ferromagnetic thin film (F) by the proximity effect with a superconducting reservoir (S). We observed oscillations of the superconducting order parameter induced in F as a function of the distance from the S/F interface. They originate from the finite momentum transfer provided to Cooper pairs by the splitting of the spin up and down bands. We measured the superconducting density of states in F by tunneling spectroscopy and the Josephson critical current when F is coupled with a superconducting counter-electrode. Negative values of the superconducting order parameter are revealed by capsized tunneling spectra in F and a negative Josephson coupling (π-junction)

WORKSHOP: Radiofrequency superconductivity

Energy Technology Data Exchange (ETDEWEB)

Anon.

1984-10-15

The Second Workshop on Radiofrequency Superconductivity was held at CERN from 23-27 July, four years after the first, organized at Karlsruhe. 35 invited talks were presented to the about 80 participants from Australia, Brazil, Europe, Japan and the United States. For the first time, ten Laboratories operating or planning superconducting accelerators for heavy ions participated and shared their experience with the community proposing the use of superconducting accelerating sections for electron accelerators.

WORKSHOP: Radiofrequency superconductivity

International Nuclear Information System (INIS)

Anon.

1984-01-01

The Second Workshop on Radiofrequency Superconductivity was held at CERN from 23-27 July, four years after the first, organized at Karlsruhe. 35 invited talks were presented to the about 80 participants from Australia, Brazil, Europe, Japan and the United States. For the first time, ten Laboratories operating or planning superconducting accelerators for heavy ions participated and shared their experience with the community proposing the use of superconducting accelerating sections for electron accelerators

Process for producing clad superconductive materials

International Nuclear Information System (INIS)

Cass, R.B.; Ott, K.C.; Peterson, D.E.

1992-01-01

This patent describes a process for fabricating superconducting composite wire. It comprises placing a superconductive precursor admixture capable of undergoing self propagating combustion in stoichiometric amounts sufficient to form a superconductive product within an oxygen-porous metal tube; sealing one end of the tube; igniting the superconductive precursor admixture whereby the superconductive precursor admixture endburns along the length of the admixture; and cross-section reducing the tube at a rate substantially equal to the rate of burning of the superconductive precursor admixture and at a point substantially planar with the burnfront of the superconductive precursor mixture, whereby a clad superconductive product is formed in situ

Organic superconductivity

International Nuclear Information System (INIS)

Jerome, D.

1980-01-01

We present the experimental evidences for the existence of a superconducting state in the Quasi One Dimensional organic conductor (TMTSF) 2 PF 6 . Superconductivity occuring at 1 K under 12 kbar is characterized by a zero resistance diamagnetic state. The anistropy of the upper critical field of this type II superconductor is consistent with the band structure anistropy. We present evidences for the existence of large superconducting precursor effects giving rise to a dominant paraconductive contribution below 40 K. We also discuss the anomalously large pressure dependence of T sb(s), which drops to 0.19 K under 24 kbar in terms of the current theories. (author)

Superconducting nanostructured materials

International Nuclear Information System (INIS)

Metlushko, V.

1998-01-01

Within the last year it has been realized that the remarkable properties of superconducting thin films containing a periodic array of defects (such as sub-micron sized holes) offer a new route for developing a novel superconducting materials based on precise control of microstructure by modern photolithography. A superconductor is a material which, when cooled below a certain temperature, loses all resistance to electricity. This means that superconducting materials can carry large electrical currents without any energy loss--but there are limits to how much current can flow before superconductivity is destroyed. The current at which superconductivity breaks down is called the critical current. The value of the critical current is determined by the balance of Lorentz forces and pinning forces acting on the flux lines in the superconductor. Lorentz forces proportional to the current flow tend to drive the flux lines into motion, which dissipates energy and destroys zero resistance. Pinning forces created by isolated defects in the microstructure oppose flux line motion and increase the critical current. Many kinds of artificial pinning centers have been proposed and developed to increase critical current performance, ranging from dispersal of small non-superconducting second phases to creation of defects by proton, neutron or heavy ion irradiation. In all of these methods, the pinning centers are randomly distributed over the superconducting material, causing them to operate well below their maximum efficiency. We are overcome this drawback by creating pinning centers in aperiodic lattice (see Fig 1) so that each pin site interacts strongly with only one or a few flux lines

Selection of number of SG modules per secondary sodium loop for a Prototype SFR

International Nuclear Information System (INIS)

Kim, Eui Kwang; Yoo, Jae-Woon; Joo, Hyung-Kook; Lee, Tae-Ho

2014-01-01

Steam generator is a vertical counter flow shell and tube heat exchanger with sodium on shell side and water-steam in tubes. The concept of steam generator modularization is discussed and the advantages of large and small steam generator modules are presented. To estimate the economics of the steam generator modularization for the PGSFR, detailed optimization studies were carried out for 1, 2, 3, 4 and 5 steam generator modules per loop, taking into consideration the effect of capital cost, operating cost, and outage cost. For the economics of the steam generator modularization for a PGSFR, detailed optimization studies were carried out for 1, 2, 3, 4 and 5 steam generator modules per loop. The effect of capital cost, operating cost, and outage cost were taken into consideration. The studies indicated that the design with less SG modules is found to be more economical, if the weld failure rate is below 2.0x1E-5 failure/year. From the economics of the modularization, thermal rate of SG, reliability, operability considerations, appropriate number of SG modules required for PGSFR will be 1 SG module per loop

Superconducting Wind Turbine Generators

Directory of Open Access Journals (Sweden)

Yunying Pan

2016-08-01

Full Text Available Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends to introduce the basic concept and principle of superconductivity, and compare form traditional wind turbine to obtain superiority, then to summary three proposed machine concept.While superconductivity have difficulty  in modern technology and we also have proposed some challenges in achieving superconducting wind turbine finally.

Superconducting cermets

International Nuclear Information System (INIS)

Goyal, A.; Funkenbusch, P.D.; Chang, G.C.S.; Burns, S.J.

1988-01-01

Two distant classes of superconducting cermets can be distinguished, depending on whether or not a fully superconducting skeleton is established. Both types of cermets have been successfully fabricated using non-noble metals, with as high as 60wt% of the metal phase. The electrical, magnetic and mechanical behavior of these composites is discussed

Removal of Secondary Side Deposit and Foreign Objects in SG of Yonggwang Nuclear Power Plant, Unit 2

Energy Technology Data Exchange (ETDEWEB)

Jeong, Wootae [KHNP-CRI, Daejeon (Korea, Republic of); Yun, Sangjung; Choi, Yongseok; Kim, Taehwa; Seo, Hongchang [Byucksan Digital Valley II, Seoul (Korea, Republic of)

2014-05-15

Mock-up test and training before the service were made to minimize operation time and radiation dose. 8 bag filters and 49 cartridge filters were consumed for filtering of soft and hard sludge in SG A, B, and C. Total 21.05 kilograms of sludge was removed. Five foreign objects were found and removed in tube bundle of SG A, in annulus and tube bundle of SG B, and in tube bundle of SG C. During the 20{sup th} OH of Yonggwang NPP unit 2, we removed 21.05 kilograms of sludge and five foreign objects from three steam generators. Gradual increase in weight of sludge removed is assumed to show us that more sludge is created as operation time of steam generator increases. Low level chemical cleaning at 19{sup th} OH removed 517 kilograms of sludge which was dominant of all the sludge removal weight. We could assume, from this fact, that high level chemical cleaning could remove significant amount of sludge compared to mechanical lancing method. Five foreign objects which were removed from inside of SG showed us that more thorough inside cleaning and inspection is necessary during fabrication of steam generator.

[sgRNA design for the CRISPR/Cas9 system and evaluation of its off-target effects].

Science.gov (United States)

Xie, Sheng-song; Zhang, Yi; Zhang, Li-sheng; Li, Guang-lei; Zhao, Chang-zhi; Ni, Pan; Zhao, Shu-hong

2015-11-01

The third generation of CRISPR/Cas9-mediated genome editing technology has been successfully applied to genome modification of various species including animals, plants and microorganisms. How to improve the efficiency of CRISPR/Cas9 genome editing and reduce its off-target effects has been extensively explored in this field. Using sgRNA (Small guide RNA) with high efficiency and specificity is one of the critical factors for successful genome editing. Several software have been developed for sgRNA design and/or off-target evaluation, which have advantages and disadvantages respectively. In this review, we summarize characters of 16 kinds online and standalone software for sgRNA design and/or off-target evaluation and conduct a comparative analysis of these different kinds of software through developing 38 evaluation indexes. We also summarize 11 experimental approaches for testing genome editing efficiency and off-target effects as well as how to screen highly efficient and specific sgRNA.

Rf superconducting devices

International Nuclear Information System (INIS)

Hartwig, W.H.; Passow, C.

1975-01-01

Topics discussed include (1) the theory of superconductors in high-frequency fields (London surface impedance, anomalous normal surface resistance, pippard nonlocal theory, quantum mechanical model, superconductor parameters, quantum mechanical calculation techniques for the surface, impedance, and experimental verification of surface impedance theories); (2) residual resistance (separation of losses, magnetic field effects, surface resistance of imperfect and impure conductors, residual loss due to acoustic coupling, losses from nonideal surfaces, high magnetic field losses, field emission, and nonlinear effects); (3) design and performance of superconducting devices (design considerations, materials and fabrication techniques, measurement of performance, and frequency stability); (4) devices for particle acceleration and deflection (advantages and problems of using superconductors, accelerators for fast particles, accelerators for particles with slow velocities, beam optical devices separators, and applications and projects under way); (5) applications of low-power superconducting resonators (superconducting filters and tuners, oscillators and detectors, mixers and amplifiers, antennas and output tanks, superconducting resonators for materials research, and radiation detection with loaded superconducting resonators); and (6) transmission and delay lines

Superconducting Ferromagnetic Nanodiamond.

Science.gov (United States)

Zhang, Gufei; Samuely, Tomas; Xu, Zheng; Jochum, Johanna K; Volodin, Alexander; Zhou, Shengqiang; May, Paul W; Onufriienko, Oleksandr; Kačmarčík, Jozef; Steele, Julian A; Li, Jun; Vanacken, Johan; Vacík, Jiri; Szabó, Pavol; Yuan, Haifeng; Roeffaers, Maarten B J; Cerbu, Dorin; Samuely, Peter; Hofkens, Johan; Moshchalkov, Victor V

2017-06-27

Superconductivity and ferromagnetism are two mutually antagonistic states in condensed matter. Research on the interplay between these two competing orderings sheds light not only on the cause of various quantum phenomena in strongly correlated systems but also on the general mechanism of superconductivity. Here we report on the observation of the electronic entanglement between superconducting and ferromagnetic states in hydrogenated boron-doped nanodiamond films, which have a superconducting transition temperature T c ∼ 3 K and a Curie temperature T Curie > 400 K. In spite of the high T Curie , our nanodiamond films demonstrate a decrease in the temperature dependence of magnetization below 100 K, in correspondence to an increase in the temperature dependence of resistivity. These anomalous magnetic and electrical transport properties reveal the presence of an intriguing precursor phase, in which spin fluctuations intervene as a result of the interplay between the two antagonistic states. Furthermore, the observations of high-temperature ferromagnetism, giant positive magnetoresistance, and anomalous Hall effect bring attention to the potential applications of our superconducting ferromagnetic nanodiamond films in magnetoelectronics, spintronics, and magnetic field sensing.

Superconductivity and its application

International Nuclear Information System (INIS)

Spadoni, M.

1988-01-01

This paper, after a short introduction to superconductivity and to multifilamentary superconducting composites is aiming to review the state of the art and the future perspective of some of the applications of the superconducting materials. The main interest is focussed to large scale applications like, for istance, magnets for accelerators or fusion reactors, superconducting system for NMR thomography, etc. A short paragraph is dedicated to applications for high sensitivity instrumentation. The paper is then concluded by some considerations about the potentialities of the newly discovered high critical temperature materials

WORKSHOPS: Radiofrequency superconductivity

International Nuclear Information System (INIS)

Anon.

1992-01-01

In the continual push towards higher energy particle beams, superconducting radiofrequency techniques now play a vital role, highlighted in the fifth workshop on radiofrequency superconductivity, held at DESY from 19 - 24 August 1991

WORKSHOPS: Radiofrequency superconductivity

Energy Technology Data Exchange (ETDEWEB)

Anon.

1992-01-15

In the continual push towards higher energy particle beams, superconducting radiofrequency techniques now play a vital role, highlighted in the fifth workshop on radiofrequency superconductivity, held at DESY from 19 - 24 August 1991.

Study on the performances of an absolute atomic gravimeter: limit sensitivity and preliminary accuracy

International Nuclear Information System (INIS)

Le Gouet, J.

2008-02-01

Atom interferometry is applied to absolute measurement of gravity acceleration g, to provide an accurate value for the realization of the LNE watt balance. The atomic source is obtained from a cloud of cold 87 Rubidium atoms. Two vertical counter-propagating are used to generate stimulated Raman transitions, that separate the wave-packets and make them interfere. During the transitions, the phase difference between the beams is printed on the phase of the free-falling atoms. Then the atomic phase shift between the two vertical paths becomes sensitive to the atom acceleration and allows obtaining an accurate value of g. A part of this manuscript is dedicated to the study of noise sources which deteriorate the measurement sensitivity. In particular, we detail the vibrations contribution, which we are able to reduce by a factor of 3 to 10, depending on the configurations, thanks to the measurement of a seismometer and to its analog processing. The best reported sensitivity, in optimal environment, is 1.4*10 -8 g/Hz 1/2 . The study of the measurement accuracy also represents an important part of this work. Although the vacuum chamber was only temporary, we started to list the systematic shifts. According to two comparisons with well-known absolute gravimeters based on optical interferometry, our measurement shows a residual bias of 16*10 -9 g. (author)

'Speedy' superconducting circuits

International Nuclear Information System (INIS)

Holst, T.

1994-01-01

The most promising concept for realizing ultra-fast superconducting digital circuits is the Rapid Single Flux Quantum (RSFQ) logic. The basic physical principle behind RSFQ logic, which include the storage and transfer of individual magnetic flux quanta in Superconducting Quantum Interference Devices (SQUIDs), is explained. A Set-Reset flip-flop is used as an example of the implementation of an RSFQ based circuit. Finally, the outlook for high-temperature superconducting materials in connection with RSFQ circuits is discussed in some details. (au)

Inferring microbial interaction networks from metagenomic data using SgLV-EKF algorithm.

Science.gov (United States)

Alshawaqfeh, Mustafa; Serpedin, Erchin; Younes, Ahmad Bani

2017-03-27

Inferring the microbial interaction networks (MINs) and modeling their dynamics are critical in understanding the mechanisms of the bacterial ecosystem and designing antibiotic and/or probiotic therapies. Recently, several approaches were proposed to infer MINs using the generalized Lotka-Volterra (gLV) model. Main drawbacks of these models include the fact that these models only consider the measurement noise without taking into consideration the uncertainties in the underlying dynamics. Furthermore, inferring the MIN is characterized by the limited number of observations and nonlinearity in the regulatory mechanisms. Therefore, novel estimation techniques are needed to address these challenges. This work proposes SgLV-EKF: a stochastic gLV model that adopts the extended Kalman filter (EKF) algorithm to model the MIN dynamics. In particular, SgLV-EKF employs a stochastic modeling of the MIN by adding a noise term to the dynamical model to compensate for modeling uncertainties. This stochastic modeling is more realistic than the conventional gLV model which assumes that the MIN dynamics are perfectly governed by the gLV equations. After specifying the stochastic model structure, we propose the EKF to estimate the MIN. SgLV-EKF was compared with two similarity-based algorithms, one algorithm from the integral-based family and two regression-based algorithms, in terms of the achieved performance on two synthetic data-sets and two real data-sets. The first data-set models the randomness in measurement data, whereas, the second data-set incorporates uncertainties in the underlying dynamics. The real data-sets are provided by a recent study pertaining to an antibiotic-mediated Clostridium difficile infection. The experimental results demonstrate that SgLV-EKF outperforms the alternative methods in terms of robustness to measurement noise, modeling errors, and tracking the dynamics of the MIN. Performance analysis demonstrates that the proposed SgLV-EKF algorithm

Superconductivity

International Nuclear Information System (INIS)

Buller, L.; Carrillo, F.; Dietert, R.; Kotziapashis, A.

1989-01-01

Superconductors are materials which combine the property of zero electric resistance with the capability to exclude any adjacent magnetic field. This leads to many large scale applications such as the much publicized levitating train, generation of magnetic fields in MHD electric generators, and special medical diagnostic equipment. On a smaller-scale, superconductive materials could replace existing resistive connectors and decrease signal delays by reducing the RLC time constants. Thus, a computer could operate at much higher speeds, and consequently at lower power levels which would reduce the need for heat removal and allow closer spacing of circuitry. Although technical advances and proposed applications are constantly being published, it should be recognized that superconductivity is a slowly developing technology. It has taken scientists almost eighty years to learn what they now know about this material and its function. The present paper provides an overview of the historical development of superconductivity and describes some of the potential applications for this new technology as it pertains to the electronics industry

Development of superconducting magnetic bearing using superconducting coil and bulk superconductor

Energy Technology Data Exchange (ETDEWEB)

Seino, H; Nagashima, K; Arai, Y [Railway Technical Research Institute, Hikari-cho 2-8-38, Kokubunji-shi, Tokyo (Japan)], E-mail: seino@rtri.or.jp

2008-02-01

The authors conducted a study on superconducting magnetic bearing, which consists of superconducting rotor and stator to apply the flywheel energy-storage system for railways. In this study, high temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. In the first step of the study, the thrust rolling bearing was selected for application by using liquid nitrogen cooled HTS bulk. 60mm-diameter HTS bulks and superconducting coil which generated a high gradient of magnetic field by cusp field were adopted as a rotor and a stator for superconducting magnetic bearing, respectively. The results of the static load test and the rotation test, creep of the electromagnetic forces caused by static flux penetration and AC loss due to eccentric rotation were decreased to the level without any problems in substantial use by using two HTS bulks. In the result of verification of static load capacity, levitation force (thrust load) of 8900N or more was supportable, and stable static load capacity was obtainable when weight of 460kg was levitated.

Development of superconducting magnetic bearing using superconducting coil and bulk superconductor

International Nuclear Information System (INIS)

Seino, H; Nagashima, K; Arai, Y

2008-01-01

The authors conducted a study on superconducting magnetic bearing, which consists of superconducting rotor and stator to apply the flywheel energy-storage system for railways. In this study, high temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. In the first step of the study, the thrust rolling bearing was selected for application by using liquid nitrogen cooled HTS bulk. 60mm-diameter HTS bulks and superconducting coil which generated a high gradient of magnetic field by cusp field were adopted as a rotor and a stator for superconducting magnetic bearing, respectively. The results of the static load test and the rotation test, creep of the electromagnetic forces caused by static flux penetration and AC loss due to eccentric rotation were decreased to the level without any problems in substantial use by using two HTS bulks. In the result of verification of static load capacity, levitation force (thrust load) of 8900N or more was supportable, and stable static load capacity was obtainable when weight of 460kg was levitated

Superconductivity basics and applications to magnets

CERN Document Server

Sharma, R G

2015-01-01

This book presents the basics and applications of superconducting magnets. It explains the phenomenon of superconductivity, theories of superconductivity, type II superconductors and high-temperature cuprate superconductors. The main focus of the book is on the application to superconducting magnets to accelerators and fusion reactors and other applications of superconducting magnets. The thermal and electromagnetic stability criteria of the conductors and the present status of the fabrication techniques for future magnet applications are addressed. The book is based on the long experience of the author in studying superconducting materials, building magnets and numerous lectures delivered to scholars. A researcher and graduate student will enjoy reading the book to learn various aspects of magnet applications of superconductivity. The book provides the knowledge in the field of applied superconductivity in a comprehensive way.

ARI3SG: Aerosol retention in the secondary side of a steam generator. Part II: Model validation and uncertainty analysis

International Nuclear Information System (INIS)

Lopez, Claudia; Herranz, Luis E.

2012-01-01

Highlights: ► Validation of a model (ARI3SG) for the aerosol retention in the break stage of a steam generator under SGTR conditions. ► Interpretation of the experimental SGTR and CAAT data by using the ARI3SG model. ► Assessment of the epistemic and stochastic uncertainties effect on the ARI3SG results. - Abstract: A large body of data has been gathered in the last decade through the EU-SGTR, ARTIST and ARTIST 2 projects for aerosol retention in the steam generator during SGTR severe accident sequences. At the same time the attempt to extend the analytical capability has resulted in models that need to be validated. The ARI3SG is one of such developments and it has been built to estimate the aerosol retention in the break stage of a “dry” steam generator. This paper assesses the ARI3SG predictability by comparing its estimates to open data and by analyzing the effect of associated uncertainties. Datamodel comparison has been shown to be satisfactory and highlight the potential use of an ARI3SG-like formulation in system codes.

Superconductivity application technologies. Superconducting quadrupole magnet and cooling system for KEK B factory

International Nuclear Information System (INIS)

Tsuchiya, Kiyosumi; Yamaguchi, Kiyoshi; Sakurabata, Hiroaki; Seido, Masahiro; Matsumoto, Kozo.

1997-01-01

At present in National Laboratory for High Energy Physics (KEK), the construction of B factory is in progress. By colliding 8 GeV electrons and 3.5 GeV positrons, this facility generates large amounts of B mesons and anti-B mesons, and performs the elementary particle experiment of high accuracy. It is the collision type accelerator of asymmetric two-ring type comprising 8 GeV and 3.5 GeV rings. In the field of high energy physics, superconductivity technology has been put to practical use. As the objects of superconductivity technology, there are dipole magnet for bending beam, quadrupole magnet for adjusting beam, large solenoid magnet used for detector and so on. Superconducting magnets which are indispensable for high energy, superconducting wire material suitable to accelerators, and the liquid helium cooling system for maintaining superconducting magnets at 4.4 K are reported. The technologies of metallic conductors and making their coils have advanced rapidly, and also cooling technology has advanced, accordingly, superconductivity technology has reached the stage of practical use perfectly. (K.I.)

Superconducting magnets and cryogenics for the steady state superconducting tokamak SST-1

International Nuclear Information System (INIS)

Saxena, Y.C.

2000-01-01

SST-1 is a steady state superconducting tokamak for studying the physics of the plasma processes in tokamak under steady state conditions and to learn technologies related to the steady state operation of the tokamak. SST-1 will have superconducting magnets made from NbTi based conductors operating at 4.5 K temperature. The design of the superconducting magnets and the cryogenic system of SST-1 tokamak are described. (author)

Vector superconductivity in cosmic strings

International Nuclear Information System (INIS)

Dvali, G.R.; Mahajan, S.M.

1992-03-01

We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

The measurement of surface gravity.

Science.gov (United States)

Crossley, David; Hinderer, Jacques; Riccardi, Umberto

2013-04-01

This review covers basic theory and techniques behind the use of ground-based gravimetry at the Earth's surface. The orientation is toward modern instrumentation, data processing and interpretation for observing surface, land-based, time-variable changes to the geopotential. The instrumentation side is covered in some detail, with specifications and performance of the most widely used models of the three main types: the absolute gravimeters (FG5, A10 from Micro-g LaCoste), superconducting gravimeters (OSG, iGrav from GWR instruments), and the new generation of spring instruments (Micro-g LaCoste gPhone, Scintrex CG5 and Burris ZLS). A wide range of applications is covered, with selected examples from tides and ocean loading, atmospheric effects on gravity, local and global hydrology, seismology and normal modes, long period and tectonics, volcanology, exploration gravimetry, and some examples of gravimetry connected to fundamental physics. We show that there are only a modest number of very large signals, i.e. hundreds of µGal (10(-8) m s(-2)), that are easy to see with all gravimeters (e.g. tides, volcanic eruptions, large earthquakes, seasonal hydrology). The majority of signals of interest are in the range 0.1-5.0 µGal and occur at a wide range of time scales (minutes to years) and spatial extent (a few meters to global). Here the competing effects require a careful combination of different gravimeter types and measurement strategies to efficiently characterize and distinguish the signals. Gravimeters are sophisticated instruments, with substantial up-front costs, and they place demands on the operators to maximize the results. Nevertheless their performance characteristics such as drift and precision have improved dramatically in recent years, and their data recording ability and ruggedness have seen similar advances. Many subtle signals are now routinely connected with known geophysical effects such as coseismic earthquake displacements, post

Foreword: Focus on Superconductivity in Semiconductors

Directory of Open Access Journals (Sweden)

Yoshihiko Takano

2008-01-01

Full Text Available Since the discovery of superconductivity in diamond, much attention has been given to the issue of superconductivity in semiconductors. Because diamond has a large band gap of 5.5 eV, it is called a wide-gap semiconductor. Upon heavy boron doping over 3×1020 cm−3, diamond becomes metallic and demonstrates superconductivity at temperatures below 11.4 K. This discovery implies that a semiconductor can become a superconductor upon carrier doping. Recently, superconductivity was also discovered in boron-doped silicon and SiC semiconductors. The number of superconducting semiconductors has increased. In 2008 an Fe-based superconductor was discovered in a research project on carrier doping in a LaCuSeO wide-gap semiconductor. This discovery enhanced research activities in the field of superconductivity, where many scientists place particular importance on superconductivity in semiconductors.This focus issue features a variety of topics on superconductivity in semiconductors selected from the 2nd International Workshop on Superconductivity in Diamond and Related Materials (IWSDRM2008, which was held at the National Institute for Materials Science (NIMS, Tsukuba, Japan in July 2008. The 1st workshop was held in 2005 and was published as a special issue in Science and Technology of Advanced Materials (STAM in 2006 (Takano 2006 Sci. Technol. Adv. Mater. 7 S1.The selection of papers describe many important experimental and theoretical studies on superconductivity in semiconductors. Topics on boron-doped diamond include isotope effects (Ekimov et al and the detailed structure of boron sites, and the relation between superconductivity and disorder induced by boron doping. Regarding other semiconductors, the superconducting properties of silicon and SiC (Kriener et al, Muranaka et al and Yanase et al are discussed, and In2O3 (Makise et al is presented as a new superconducting semiconductor. Iron-based superconductors are presented as a new series of high

Status of RF superconductivity at Argonne

International Nuclear Information System (INIS)

Shepard, K.W.

1990-01-01

Development of a superconducting slow-wave structures began at Argonne National Laboratory (ANL) in 1971, and led to the first superconducting heavy-ion linac (ATLAS - the Argonne Tandem-Linac Accelerator System). The Physics Division at ANL has continued to develop superconducting RF technology for accelerating heavy-ions, with the result that the linac has been in an almost continuous process of upgrade and expansion. In 1987, the Engineering Physics Division at ANL began developing of superconducting RF components for the acceleration of high-brightness proton and deuterium beams. The two divisions collaborate in work on several applications of RF superconductivity, and also in work to develop the technology generally. The present report briefly describes major features of the superconducting heavy-ion linac (very-low-velocity superconducting linac, positive ion injector), proton accelerating structures (superconducting resonant cavities for acceleration of high-current proton and deuteron beams, RF properties of oxide superconductors), and future work. Both divisions expect to continue a variety of studies, frequently in collaboration, to advance the basic technology of RF superconductivity. (N.K.)

Unconventional superconductivity in heavy-fermion compounds

Energy Technology Data Exchange (ETDEWEB)

White, B.D. [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093 (United States); Thompson, J.D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maple, M.B., E-mail: mbmaple@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093 (United States)

2015-07-15

Highlights: • Quasiparticles in heavy-fermion compounds are much heavier than free electrons. • Superconductivity involves pairing of these massive quasiparticles. • Quasiparticle pairing mediated by magnetic or quadrupolar fluctuations. • We review the properties of superconductivity in heavy-fermion compounds. - Abstract: Over the past 35 years, research on unconventional superconductivity in heavy-fermion systems has evolved from the surprising observations of unprecedented superconducting properties in compounds that convention dictated should not superconduct at all to performing explorations of rich phase spaces in which the delicate interplay between competing ground states appears to support emergent superconducting states. In this article, we review the current understanding of superconductivity in heavy-fermion compounds and identify a set of characteristics that is common to their unconventional superconducting states. These core properties are compared with those of other classes of unconventional superconductors such as the cuprates and iron-based superconductors. We conclude by speculating on the prospects for future research in this field and how new advances might contribute towards resolving the long-standing mystery of how unconventional superconductivity works.

Superconducting wires and methods of making thereof

Energy Technology Data Exchange (ETDEWEB)

Xu, Xingchen; Sumption, Michael D.; Peng, Xuan

2018-03-13

Disclosed herein are superconducting wires. The superconducting wires can comprise a metallic matrix and at least one continuous subelement embedded in the matrix. Each subelement can comprise a non-superconducting core, a superconducting layer coaxially disposed around the non-superconducting core, and a barrier layer coaxially disposed around the superconducting layer. The superconducting layer can comprise a plurality of Nb.sub.3Sn grains stabilized by metal oxide particulates disposed therein. The Nb.sub.3Sn grains can have an average grain size of from 5 nm to 90 nm (for example, from 15 nm to 30 nm). The superconducting wire can have a high-field critical current density (J.sub.c) of at least 5,000 A/mm.sup.2 at a temperature of 4.2 K in a magnetic field of 12 T. Also described are superconducting wire precursors that can be heat treated to prepare superconducting wires, as well as methods of making superconducting wires.

Superconducting magnet development in Japan

International Nuclear Information System (INIS)

Yasukochi, K.

1983-01-01

The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb 3 Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting μ meson channel and π meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration

Superconducting joint of Bi-2223/Ag superconducting tapes by diffusion bonding

International Nuclear Information System (INIS)

Guo Wei; Zou Guisheng; Wu Aiping; Wang Yanjun; Bai Hailin; Ren Jialie

2009-01-01

61-Filaments Bi-2223/Ag superconducting tapes have been joined by diffusion bonding. The critical currents (I C s) of the joints are obtained by using standard four probe method under no magnetic field in the liquid nitrogen. The microstructures of the joints are evaluated by the electron microscope in electron backscatter diffraction mode and the phase compositions of the superconducting cores of the joint and the original tape are determined by X-ray diffraction (XRD). The results show diffusion bonding is effective bonding technique for HTS tapes, and the bonding time is reduced greatly from hundreds of hours to a few hours, and the bonding pressure also changes from 140-4000 MPa to 3 MPa. Furthermore, the diffusion bonding joints sustain superconducting properties, and the critical current ratios (CCR O ) of the joints are in the range of 35%-80%. Microstructures of the typical joint display a good bonding and some defects existed in traditional method are avoided. XRD results show that the phase compositions of the superconducting cores have no obvious changes before and after diffusion bonding, which offers physical and material bases for high superconducting property of the joints.

Superconductivity in the 1990's

International Nuclear Information System (INIS)

Stekly, Z.J.J.

1990-01-01

Superconducting magnets, coils or windings are the basis for a range of major applications in the energy area such as energy storage in superconducting coils, magnets for fusion research, and rotating machinery. Other major applications of superconductivity include high energy physics where 1000 superconducting magnets are operated continuously in the Tevatron at Fermilab in Illinois, over 12,000 superconducting magnets will be required for the superconducting Super Collider being build near Dallas. The largest commercial application of superconductors is in magnets for magnetic resonance imaging (MRI) - a new medical diagnostic imaging technique with about 2,000 systems installed worldwide. These form a sizable technology base on which to evaluate and push forward applications such as magneto hydrodynamic propulsion of seagoing vessels. The attractiveness of which depends ultimately on the characteristics of the superconducting magnet. The magnet itself is a combination of several technology areas - the conductors, magnetics, structures and cryogenics. This paper reviews state-of-the-art in each of the technology areas as they relate to superconductors

Superconductivity in doped Dirac semimetals

Science.gov (United States)

Hashimoto, Tatsuki; Kobayashi, Shingo; Tanaka, Yukio; Sato, Masatoshi

2016-07-01

We theoretically study intrinsic superconductivity in doped Dirac semimetals. Dirac semimetals host bulk Dirac points, which are formed by doubly degenerate bands, so the Hamiltonian is described by a 4 ×4 matrix and six types of k -independent pair potentials are allowed by the Fermi-Dirac statistics. We show that the unique spin-orbit coupling leads to characteristic superconducting gap structures and d vectors on the Fermi surface and the electron-electron interaction between intra and interorbitals gives a novel phase diagram of superconductivity. It is found that when the interorbital attraction is dominant, an unconventional superconducting state with point nodes appears. To verify the experimental signature of possible superconducting states, we calculate the temperature dependence of bulk physical properties such as electronic specific heat and spin susceptibility and surface state. In the unconventional superconducting phase, either dispersive or flat Andreev bound states appear between point nodes, which leads to double peaks or a single peak in the surface density of states, respectively. As a result, possible superconducting states can be distinguished by combining bulk and surface measurements.

Numerical analyses of the effect of SG-interlayer shear stiffness on the structural performance of reinforced glass beams

DEFF Research Database (Denmark)

Louter, C.; Nielsen, Jens Henrik

2013-01-01

This paper focuses on the numerical modelling of SentryGlas-laminated reinforced glass beams. In these beams, which have been experimentally investigated in preceding research, a stainless steel reinforcement section is laminated at the inner recessed edge of a triple-layer glass beam by means...... of SentryGlas (SG) interlayer sheets. The current contribution numerically investigates the effect of the SG-interlayer shear stiffness on the overall structural response of the beams. This is done by means of a 3D finite element model in which the individual glass layers, the SG......-interlayers and the reinforcement are incorporated. In the model, the glass parts are allowed to crack, but all other parts are assumed linear elastic throughout the analyses. By changing the shear modulus of the SG-interlayer in multiple analyses, its contribution to the overall structural performance of the beams - especially...

Superconductivity: materials and applications

International Nuclear Information System (INIS)

Duchateau, J.L.; Kircher, F.; Leveque, J.; Tixador, P.

2008-01-01

This digest paper presents the different types of superconducting materials: 1 - the low-TC superconductors: the multi-filament composite as elementary constituent, the world production of NbTi, the superconducting cables of the LHC collider and of the ITER tokamak; 2 - the high-TC superconductors: BiSrCaCuO (PIT 1G) ribbons and wires, deposited coatings; 3 - application to particle physics: the the LHC collider of the CERN, the LHC detectors; 4 - applications to thermonuclear fusion: Tore Supra and ITER tokamaks; 5 - NMR imaging: properties of superconducting magnets; 6 - applications in electrotechnics: cables, motors and alternators, current limiters, transformers, superconducting energy storage systems (SMES). (J.S.)

Superconductivity in power engineering

International Nuclear Information System (INIS)

1989-01-01

This proceedings volume presents 24 conference papers and 15 posters dealing with the following aspects: 1) Principles and elementary aspects of high-temperature superconductivity (3 plenary lectures); 2) Preparation, properties and materials requirements of metallic or oxide superconductors (critical current behaviour, soldered joints, structural studies); 3) Magnet technology (large magnets for thermonuclear fusion devices; magnets for particle accelerators and medical devices); 4) Magnetic levitation and superconductivity; 5) Cryogenics; 6) Energy storage systems using superconducting coils (SMES); 7) Superconducting power transmission cables, switches, transformers, and generator systems for power plant; 8) Supporting activities, industrial aspects, patents. There are thirty-eight records in the ENERGY database relating to individual conference papers. (MM) [de

High-Tc superconducting electric motors

International Nuclear Information System (INIS)

Schiferl, R.; Stein, J.

1992-01-01

In this paper, the advantages and limitations of using superconductors in motors are discussed. A synchronous motor with a high temperature superconducting field winding for pump and fan drive applications is described and some of its unique design features are identified. A 10,000 horsepower superconducting motor design is presented. The critical field and current density requirements for high temperature superconducting wire in motors is discussed. Finally, recent progress in superconducting wire performance is presented

Dispersant Application during SG Wet Layup at SK Unit 1

Energy Technology Data Exchange (ETDEWEB)

Kwon, Hyukchul; Lee, Dooho; Sung, Kibang [KHNP Central Institute, Daejeon (Korea, Republic of)

2014-05-15

The corrosion products in the feedwater are deposited onto the steam generators (SGs) despite the effort to control them within limit of impurity. This deposit is one of causes for occurrence of SCC (Stress Corrosion Cracking), water level fluctuation and further corrosion of SGs. To minimize corrosion and remove deposit, the nuclear power plants apply high pH to the secondary system and SG chemical cleaning, respectively. But these methods can be costly and carry risks of extended outages or incomplete cleaning. Another method is an on-line dispersant application. The role of dispersant is to make deposit suspended in the SGs. Then, the suspended deposit is discharged to the blowdown system. The iron removal is increased in the blowdown system during the dispersant application. Additional significant benefit in the form of reduced corrosion product transport may be obtained through applying dispersant in the SGs wet lay operational mode. This method helps to reduce the total SGs loading without affecting critical outage activities and with minimal additional effort on the part of the utilities. This study provides the results of the dispersant application trial during the SG wet layup at SK Unit 1. As the PAA concentrations were increased, the corrosion rates of Alloy 690 and SA 106 Gr.B were increased. The corrosion rate of Alloy 690 was 2 times less than that of SA 106 Gr.B at 100 ppm of PAA based on the electrochemical experimental. There were no significant feasibility problems with application of PAA during the SG wet layup. The reasonable estimation of the additional mass removed by the presence of PAA during SGs wet layup is 460 g. The iron removal depended on PAA concentration injected based on the comparative results of the SK Unit 1 and TMI-1. It is expected that injection of PAA into the SG result in a significant decrease in the amount of iron transported to the SGs during the startup.

Improved management of SG BD demineralizer for reduced generation of low-level radioactive spent resin in Korean nuclear power plants

International Nuclear Information System (INIS)

Rhee, I.; Cho, D.; Yeon, J.

2003-01-01

Most nuclear power plants in Korea have adopted Ethanolamine(ETA) as a secondary pH control agent to increase the pH at the liquid phase, which may reduce the corrosion in steam generator tubes and moisture separator/reheat system. Along with its beneficial effect of SG protection from corrosion and degradation, the replacement of ammonia with ETA causes the increased generation of spent resin and the reduced run time of demineralizer in steam generator blowdown(SG BD) system. The composition ratio of cation- to anion- exchange resin in SG BD mixed bed should be increased in the ETA chemistry environment to meet the ratio of cation to anion in the aqueous solution, which results in the simultaneous exhaustion of cation and anion exchange resins. The utilization rate of mixed bed is greatest at the cation-to-anion ratio of 95:1 on the theoretical equivalent basis in the solution, but practically highest at that of 22:1 due to the possible inhomogeneous distribution of cation and anion exchange resins in SG BD bed. The run time of the bed could be extended by 30% such that, at that much, the purchase cost of new resin is saved and the production rate of spent resin is reduced. The guideline on the replacement of resin in SG BD bed is not necessary to secure the removal of radioactive particles without the leakage of the primary coolant into the secondary side since all the radioactive ions can be eliminated by SG BD bed with the sufficient time. They are retained during more than one month after their ingress into the SG BD bed without leakage. With the reduced replacement, thus, the SG BD spent resin that comprises 65% of low-level radioactive solid waste can be much cut down

STAC -- a new Swedish code for statistical analysis of cracks in SG-tubes

International Nuclear Information System (INIS)

Poern, K.

1997-01-01

Steam generator (SG) tubes in pressurized water reactor plants are exposed to various types of degradation processes, among which stress corrosion cracking in particular has been observed. To be able to evaluate the safety importance of such cracking of SG-tubes one has to have a good and empirically founded knowledge about the scope and the size of the cracks as well as the rate of their continuous growth. The basis of experience is to a large extent constituted of the annually performed SG-inspections and crack sizing procedures. On the basis of this experience one can estimate the distribution of existing crack lengths, and modify this distribution with regard to maintenance (plugging) and the predicted rate of crack propagation. Finally, one can calculate the rupture probability of SG-tubes as a function of a given critical crack length. On account of the Swedish Nuclear Power Inspectorate an introductory study has been performed in order to get a survey of what has been done elsewhere in this field. The study resulted in a proposal of a computerizable model to be able to estimate the distribution of true cracks, to modify this distribution due to the crack growth and to compute the probability of tube rupture. The model has now been implemented in a compute code, called STAC (STatistical Analysis of Cracks). This paper is aimed to give a brief outline of the model to facilitate the understanding of the possibilities and limitations associated with the model

Superconducting magnets for a muon collider

International Nuclear Information System (INIS)

Green, M.A.

1996-01-01

The existence of a muon collider will be dependent on the use of superconducting magnets. Superconducting magnets for the μ - μ + collider will be found in the following locations: the π - π + capture system, the muon phase rotation system, the muon cooling system, the recirculating acceleration system, the collider ring, and the collider detector system. This report describes superconducting magnets for each of these sections except the detector. In addition to superconducting magnets, superconducting RF cavities will be found in the recirculating accelerator sections and the collider ring. The use of superconducting magnets is dictated by the need for high magnetic fields in order to reduce the length of various machine components. The performance of all of the superconducting magnets will be affected the energy deposited from muon decay products. (orig.)

Simulation of the condensation experiment for the SG primary of SMART with MIDAS/SMR

Energy Technology Data Exchange (ETDEWEB)

Park, Jong Hwa; Kim, Dong Ha; Chung, Young Jong; Park, Sun Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seong Won [Korea Radiation Technology Institute Co., Daejeon (Korea, Republic of)

2012-05-15

SMART is new concept of reactor that all the main components such as the steam generator, the coolant pumps and the pressurizer are located inside the reactor vessel. MIDAS/SMR V1.0.3 code has been used for estimating the severe accident from SMART. SMART has the SG tube with helical shape that is different from that of PWR. MIDAS code has the condensation model for the both sides of surfaces from the various kinds of geometry. But it does not have the condensation model for the helical type of tube. In this study, the condensation experiment for the outer surface of the SG tube in SMART that was performed by Po-Hang university was simulated with MIDAS/SMR under the assumption of straight pipe. The simulation results showed well predictions of the amount of heat removal from the SG tube primary side and thermal hydraulic parameters

Simulation of the condensation experiment for the SG primary of SMART with MIDAS/SMR

International Nuclear Information System (INIS)

Park, Jong Hwa; Kim, Dong Ha; Chung, Young Jong; Park, Sun Hee; Cho, Seong Won

2012-01-01

SMART is new concept of reactor that all the main components such as the steam generator, the coolant pumps and the pressurizer are located inside the reactor vessel. MIDAS/SMR V1.0.3 code has been used for estimating the severe accident from SMART. SMART has the SG tube with helical shape that is different from that of PWR. MIDAS code has the condensation model for the both sides of surfaces from the various kinds of geometry. But it does not have the condensation model for the helical type of tube. In this study, the condensation experiment for the outer surface of the SG tube in SMART that was performed by Po-Hang university was simulated with MIDAS/SMR under the assumption of straight pipe. The simulation results showed well predictions of the amount of heat removal from the SG tube primary side and thermal hydraulic parameters

Dual-Emission SG7@MOF Sensor via SC-SC Transformation: Enhancing the Formation of Excimer Emission and the Range and Sensitivity of Detection.

Science.gov (United States)

Fu, Hong-Ru; Wu, Xiao-Xia; Ma, Lu-Fang; Wang, Fei; Zhang, Jian

2018-05-30

In this study, a water stable metal-organic framework FIR-53 is applied as a single-crystal container for anion exchange. The exceptional chemical stability and low crystallographic symmetry of FIR-53 makes it possible to determine anionic guests. Through ion exchange and single-crystal to single-crystal (SC-SC) transformation, 8-hydroxypyrene-1,3,6-trisulfonate (SG7, solvent green 7, ion form as SG7 3- ) is introduced into the pores of FIR-53 to obtain SG7@FIR-53. Because of the spatial confinement and partition effect, SG7@FIR-53 shows the bright exciter emission of SG7 ions. Interestingly, the composite SG7@FIR-53 exhibits a sensitive fluorescence quenching response against Cr 2 O 7 2- and MnO 4 - in aqueous solution. Especially, the detection limit toward MnO 4 - is as low as 0.12 ppb, which is the smallest value to date. Moreover, the prepared SG7@FIR-53 film also displays a broad response to nitro explosives in vapor/aqueous phase. Compared with the results of FIR-53, the range and sensitivity were greatly improved.

Superconducting wind turbine generators

DEFF Research Database (Denmark)

Abrahamsen, Asger Bech; Mijatovic, Nenad; Seiler, Eugen

2010-01-01

, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10......We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future...... offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However...

Three-terminal superconducting devices

International Nuclear Information System (INIS)

Gallagher, W.J.

1985-01-01

The transistor has a number of properties that make it so useful. The authors discuss these and the additional properties a transistor would need to have for high performance applications at temperatures where superconductivity could contribute advantages to system-level performance. These properties then serve as criteria by which to evaluate three-terminal devices that have been proposed for applications at superconducting temperatures. FETs can retain their transistor properties at low temperatures, but their power consumption is too large for high-speed, high-density cryogenic applications. They discuss in detail why demonstrated superconducting devices with three terminals -Josephson effect based devices, injection controlled weak links, and stacked tunnel junction devices such as the superconducting transistor proposed by K. Gray and the quiteron -- each fail to have true transistor-like properties. They conclude that the potentially very rewarding search for a transistor compatible with superconductivity in high performance applications must be in new directions

Korea's developmental program for superconductivity

Science.gov (United States)

Hong, Gye-Won; Won, Dong-Yeon; Kuk, Il-Hyun; Park, Jong-Chul

1995-04-01

Superconductivity research in Korea was firstly carried out in the late 70's by a research group in Seoul National University (SNU), who fabricated a small scale superconducting magnetic energy storage system under the financial support from Korea Electric Power Company (KEPCO). But a few researchers were involved in superconductivity research until the oxide high Tc superconductor was discovered by Bednorz and Mueller. After the discovery of YBaCuO superconductor operating above the boiling point of liquid nitrogen (77 K)(exp 2), Korean Ministry of Science and Technology (MOST) sponsored a special fund for the high Tc superconductivity research to universities and national research institutes by recognizing its importance. Scientists engaged in this project organized 'High Temperature Superconductivity Research Association (HITSRA)' for effective conducting of research. Its major functions are to coordinate research activities on high Tc superconductivity and organize the workshop for active exchange of information. During last seven years the major superconductivity research has been carried out through the coordination of HITSRA. The major parts of the Korea's superconductivity research program were related to high temperature superconductor and only a few groups were carrying out research on conventional superconductor technology, and Korea Atomic Energy Research Institute (KAERI) and Korea Electrotechnology Research Institute (KERI) have led this research. In this talk, the current status and future plans of superconductivity research in Korea will be reviewed based on the results presented in interim meeting of HITSRA, April 1-2, 1994. Taejeon, as well as the research activity of KAERI.

The new isotope 270110 and its decay products 266Hs and 262Sg

International Nuclear Information System (INIS)

Hofmann, S.; Hessberger, F.P.; Ackermann, D.

2000-11-01

The even-even nucleus 270 110 was synthesized using the reaction 64 Ni + 207 Pb. A total of eight α-decay chains was measured during an irradiation time of seven days. Decay data were obtained for the ground-state and a high spin K isomer. The new nuclei 266 Hs and 262 Sg were identified as daughter products after α decay. Spontaneous fission of 262 Sg terminates the decay chain. The measured data are in agreement with calculations using the macroscopic-microscopic model and with self-consistent HFB calculations with Skyrme-Sly4 interaction. (orig.)

Superconducting machines. Chapter 4

International Nuclear Information System (INIS)

Appleton, A.D.

1977-01-01

A brief account is given of the principles of superconductivity and superconductors. The properties of Nb-Ti superconductors and the method of flux stabilization are described. The basic features of superconducting d.c. machines are illustrated by the use of these machines for ship propulsion, steel-mill drives, industrial drives, aluminium production, and other d.c. power supplies. Superconducting a.c. generators and their design parameters are discussed. (U.K.)

Free electron laser amplifier experiments on SG-1

International Nuclear Information System (INIS)

Hui Zhongxi; Zhou Chuanming; Wu Ruian

1994-01-01

The SG-1 FEL facility is composed of a linear induction accelerator (LIA), an electron beam transport system, a wiggler, a microwave source and a diagnostic system. SG-1 LIA provides a 2 kA, 3.0 MeV beam with a normalized emittance of 0.4∼0.6 (π rad·cm), an energy spread (FWHM) of 4%, resulting in a beam brightness of nearly 10 8 A/πm·rad) 2[1] . The beam current through the wiggler is about 600 A. The first ASE experiments began in September 1991. A 2.6-m long wiggler with a peak magnetic field of 0.3 T was used. At 35.8∼36.5 GHz an ASE output of 0.5 W was obtained for a beam current of nearly 50 A. After a shutdown of about 8 months, the second series of ASE experiments began in October 1992. The second series of ASE experiments were performed with a wiggler magnetic field between 0.25∼0.27 T. The maximum output power is about 100 kw for B w = 0.24 T, I = 600 A, At ν = 35.2 GHz. Based on the ASE experiments the amplifier experiments was carried out on SG-1. Using an 300 W input signal (TE 01 ), a beam current of about 600 A and wiggler magnetic fields of 0.24∼0.28 T, the authors measured the FEL output power as a function of the wiggler magnetic field. The resonant magnetic field was about 0.25 T. Meanwhile, in order to study the amplifier gain, the authors measured the FEL output power as a function of the wiggler length at a peak wiggler magnetic field of 0.26 T. The exponential gain is approximately 19 dB/m and the maximum output power is about 10 MW

Superconductivity at the industrial scale

International Nuclear Information System (INIS)

Tixador, P.; Lebrun, Ph.

2011-01-01

The discovery of superconductivity is 100 years old but theoretical works are still necessary: the BCS theory does not apply to the new families of high temperature superconducting materials discovered after 1986. In 2001 it was discovered that MgB 2 is superconducting at 39 K, this critical temperature is not the highest but MgB 2 is easy to produce and cheap. Today's highest critical temperature under atmospheric pressure is that of the HgTlBaCaCuO compound: 138 K. The complexity and the cost of cryogenic systems restrain the applications of superconductivity. The author reviews the applications of superconducting in medical imaging, particle detectors, and in the safety systems of power networks. (A.C.)

Process of producing superconducting bar magnets

International Nuclear Information System (INIS)

Wilson, M.A.

1988-01-01

A method of forming a magnet having an established magnetic field is described comprising; (1) establishing a magnetic field of the desired extent and shape; (2) providing a superconducting material of desired shape; (3) positioning the material of (2) in field (1) while at a temperature above the critical temperature of the superconducting material so as to apply a magnetic field on the superconducting material; (4) cooling the superconducting material while in magnetic field (1) to below the critical temperature of the superconducting material; (5) removing the superconducting material from the magnetic field while in the supercooled condition; and (6) maintaining the material at or below the critical temperature

Superconductivity and its devices

International Nuclear Information System (INIS)

Forbes, D.S.

1981-01-01

Among the more important developments that are discussed are cryotrons, superconducting motors and generators, and high-field magnets. Cryotrons will create faster and more economical computer systems. Superconducting motors and generators will cost much less to build than conventional electric generators and cut fuel consumption. Moreover, high-field magnets are being used to confine plasma in connection with nuclear fusion. Superconductors have a vital role to play in all of these developments. Most importantly, though, are the magnetic properties of superconductivity. Superconducting magnets are an integral part of nuclear fusion. In addition, high-field magnets are necessary in the use of accelerators, which are needed to study the interactions between elementary particles

Superconductivity

CERN Document Server

Poole, Charles P; Creswick, Richard J; Prozorov, Ruslan

2014-01-01

Superconductivity, Third Edition is an encyclopedic treatment of all aspects of the subject, from classic materials to fullerenes. Emphasis is on balanced coverage, with a comprehensive reference list and significant graphics from all areas of the published literature. Widely used theoretical approaches are explained in detail. Topics of special interest include high temperature superconductors, spectroscopy, critical states, transport properties, and tunneling. This book covers the whole field of superconductivity from both the theoretical and the experimental point of view. This third edition features extensive revisions throughout, and new chapters on second critical field and iron based superconductors.

Superconducting elliptical cavities

CERN Document Server

Sekutowicz, J K

2011-01-01

We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

Unconventional superconductivity in honeycomb lattice

Directory of Open Access Journals (Sweden)

P Sahebsara

2013-03-01

Full Text Available   ‎ The possibility of symmetrical s-wave superconductivity in the honeycomb lattice is studied within a strongly correlated regime, using the Hubbard model. The superconducting order parameter is defined by introducing the Green function, which is obtained by calculating the density of the electrons ‎ . In this study showed that the superconducting order parameter appears in doping interval between 0 and 0.5, and x=0.25 is the optimum doping for the s-wave superconductivity in honeycomb lattice.

2017 Gordon Conference on Superconductivity

Energy Technology Data Exchange (ETDEWEB)

Chubukov, Andrey [Univ. of Minnesota, Twin Cities, MN (United States)

2017-11-14

The DOE award was for a 2017 Gordon Research conference on Superconductivity (GRC). The objective of GRC is to interchange the information about the latest theoretical and experimental developments in the area of superconductivity and to select most perspective directions for future research in this area.The goal of the Gordon Conference on Superconductivity is to present and discuss the latest results in the field of modern superconductivity, discuss new ideas and new directions of research in the area. It is a long-standing tradition of the Gordon conference on Superconductivity that the vast majority of participants are junior scientists. Funding for the conference would primarily be used to support junior researchers, particularly from under-represented groups. We had more 10 female speakers, some of them junior researchers, and some funding was used to support these speakers. The conference was held together with Gordon Research Seminar on Superconductivity, where almost all speakers and participants were junior scientists.

Multiplex Conditional Mutagenesis Using Transgenic Expression of Cas9 and sgRNAs.

Science.gov (United States)

Yin, Linlin; Maddison, Lisette A; Li, Mingyu; Kara, Nergis; LaFave, Matthew C; Varshney, Gaurav K; Burgess, Shawn M; Patton, James G; Chen, Wenbiao

2015-06-01

Determining the mechanism of gene function is greatly enhanced using conditional mutagenesis. However, generating engineered conditional alleles is inefficient and has only been widely used in mice. Importantly, multiplex conditional mutagenesis requires extensive breeding. Here we demonstrate a system for one-generation multiplex conditional mutagenesis in zebrafish (Danio rerio) using transgenic expression of both cas9 and multiple single guide RNAs (sgRNAs). We describe five distinct zebrafish U6 promoters for sgRNA expression and demonstrate efficient multiplex biallelic inactivation of tyrosinase and insulin receptor a and b, resulting in defects in pigmentation and glucose homeostasis. Furthermore, we demonstrate temporal and tissue-specific mutagenesis using transgenic expression of Cas9. Heat-shock-inducible expression of cas9 allows temporal control of tyr mutagenesis. Liver-specific expression of cas9 disrupts insulin receptor a and b, causing fasting hypoglycemia and postprandial hyperglycemia. We also show that delivery of sgRNAs targeting ascl1a into the eye leads to impaired damage-induced photoreceptor regeneration. Our findings suggest that CRISPR/Cas9-based conditional mutagenesis in zebrafish is not only feasible but rapid and straightforward. Copyright © 2015 by the Genetics Society of America.

Superconductivity and their applications

OpenAIRE

Roque, António; Sousa, Duarte M.; Fernão Pires, Vítor; Margato, Elmano

2017-01-01

Trabalho apresentado em International Conference on Renewable Energies and Power Quality (ICREPQ’17), 4 a 6 de Abril de 2017, Málaga, Espanha The research in the field of superconductivity has led to the synthesis of superconducting materials with features that allow you to expand the applicability of this kind of materials. Among the superconducting materials characteristics, the critical temperature of the superconductor is framing the range and type of industrial applications that can b...

Superconducting wind turbine generators

International Nuclear Information System (INIS)

Abrahamsen, A B; Seiler, E; Zirngibl, T; Andersen, N H; Mijatovic, N; Traeholt, C; Pedersen, N F; Oestergaard, J; Noergaard, P B

2010-01-01

We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

The Finnish subtitling of neologisms in the science fiction television series Stargate SG-1

OpenAIRE

Kurki, Riikka

2012-01-01

Tämä pro gradu -tutkielma käsittelee kanadalais–amerikkalaisen tieteissarjan Stargate SG-1 (tunnettu Suomessa myös nimellä Tähtiportti) neologismien eli uudissanojen tekstitystä englannista suomeksi. Uudissana on sana, joka ei ole virallisissa sanakirjoissa tai jolla on sanakirjoissa eri merkitys kuin sen uudessa käyttömuodossa. Tutkimusta varten on kerätty kaikki uudissanat Stargate SG-1 -sarjan seitsemännen tuotantokauden DVD-julkaisulta ja analysoitu, millaisia käännöstekniikoita sarjan ka...

Superconductivity from magnetic elements under high pressure

International Nuclear Information System (INIS)

Shimizu, Katsuya; Amaya, Kiichi; Suzuki, Naoshi; Onuki, Yoshichika

2006-01-01

Can we expect the appearance of superconductivity from magnetic elements? In general, superconductivity occurs in nonmagnetic metal at low temperature and magnetic impurities destroy superconductivity; magnetism and superconductivity are as incompatible as oil and water. Here, we present our experimental example of superconducting elements, iron and oxygen. They are magnetic at ambient pressure, however, they become nonmagnetic under high pressure, then superconductor at low temperature. What is the driving force of the superconductivity? Our understanding in the early stages was a simple scenario that the superconductive state was obtained as a consequence of an emergence of the nonmagnetic states. In both cases, we may consider another scenario for the appearance of superconductivity; the magnetic fluctuation mechanism in the same way as unconventional superconductors

Analysis of mechanical characteristics of superconducting field coil for 17 MW class high temperature superconducting synchronous motor

International Nuclear Information System (INIS)

Kim, J. H.; Park, S. I.; Im, S. H.; Kim, H. M.

2013-01-01

Superconducting field coils using a high-temperature superconducting (HTS) wires with high current density generate high magnetic field of 2 to 5 [T] and electromagnetic force (Lorentz force) acting on the superconducting field coils also become a very strong from the point of view of a mechanical characteristics. Because mechanical stress caused by these powerful electromagnetic force is one of the factors which worsens the critical current performance and structural characteristics of HTS wire, the mechanical stress analysis should be performed when designing the superconducting field coils. In this paper, as part of structural design of superconducting field coils for 17 MW class superconducting ship propulsion motor, mechanical stress acting on the superconducting field coils was analyzed and structural safety was also determined by the coupling analysis system that is consists of commercial electromagnetic field analysis program and structural analysis program.

Superconducted tour

Energy Technology Data Exchange (ETDEWEB)

Anon.

1988-09-15

Superconductivity - the dramatic drop in electrical resistance in certain materials at very low temperatures - has grown rapidly in importance over the past two or three decades to become a key technology for high energy particle accelerators. It was in this setting that a hundred students and 15 lecturers met in Hamburg in June for a week's course on superconductivity in particle accelerators, organized by the CERN Accelerator School and the nearby DESY Laboratory.

Superconductivity: Phenomenology

International Nuclear Information System (INIS)

Falicov, L.M.

1988-08-01

This document discusses first the following topics: (a) The superconducting transition temperature; (b) Zero resistivity; (c) The Meissner effect; (d) The isotope effect; (e) Microwave and optical properties; and (f) The superconducting energy gap. Part II of this document investigates the Ginzburg-Landau equations by discussing: (a) The coherence length; (b) The penetration depth; (c) Flux quantization; (d) Magnetic-field dependence of the energy gap; (e) Quantum interference phenomena; and (f) The Josephson effect

Introduction to superconductivity

CERN Document Server

Darriulat, Pierre

1998-01-01

The lecture series will address physicists, such as particle and nuclear physicists, familiar with non-relativistic quantum mechanics but not with solid state physics. The aim of this introduction to low temperature superconductivity is to give sufficient bases to the student for him/her to be able to access the scientific literature on this field. The five lectures will cover the following topics : 1. Normal metals, free electron gas, chambers equation. 2. Cooper pairs, the BCS ground state, quasi particle excitations. 3. DC superconductivity, Meissner state, dirty superconductors.4. Self consistent approach, Ginsburg Landau equations, Abrikosov fluxon lattice. 5. Josephson effects, high temperature superconductivity.

The development of superconducting equipment

CERN Document Server

Ueda, T; Hiue, H

2003-01-01

Fuji Electric has been developing various types of superconducting equipment for over a quarter of a century. This paper describes the development results achieved for superconducting equipment and especially focuses on large-capacity current leads and superconducting transmission systems, the development of which is being promoted for application to the field of nuclear fusion. High temperature superconductor (HTS) is becoming the mainstream in the field of superconductivity, and the HTS floating coil and conduction-cooled HTS transformed are also introduced as recent developments for devices that utilize this technology. (author)

Significance of Lignin S/G Ratio in Biomass Recalcitrance of Populus trichocarpa Variants for Bioethanol Production

Energy Technology Data Exchange (ETDEWEB)

Yoo, Chang Geun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dumitrache, Alexandru [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Muchero, Wellington [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Natzke, Jace [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Akinosho, Hannah [Georgia Inst. of Technology, Atlanta, GA (United States); Li, Mi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sykes, Robert W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brown, Steven D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Davison, Brian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tuskan, Gerald A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pu, Yunqiao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ragauskas, Arthur J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

2017-12-11

Lignin S/G ratio has been investigated as an important factor in biomass recalcitrance to bioethanol production. Because of the complexity and variety of biomass, recalcitrance was also reportedly influenced by several other factors, such as total lignin content, degree of cellulose polymerization, etc. In addition, the effect of S/G ratio on biomass conversion is not uniform across plant species. Herein, 11 Populus trichocarpa natural variants grown under the same conditions with similar total lignin content were selected to minimize the effects of other factors. The lignin S/G ratio of the selected P. trichocarpa natural variants showed negative correlations with p-hydroxybenzoate (PB) and β–5 linkage contents, while it had positive ones with β-O-4 linkage, lignin molecular weight, and ethanol production. In conclusion, this study showed the importance of lignin S/G ratio as an independent recalcitrance factor that may aid future energy crop engineering and biomass conversion strategies.

Significance of Lignin S/G Ratio in Biomass Recalcitrance of Populus trichocarpa Variants for Bioethanol Production

Energy Technology Data Exchange (ETDEWEB)

Yoo, Chang Geun [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; UT−ORNL; Dumitrache, Alexandru [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; Muchero, Wellington [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; Natzke, Jace [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; Akinosho, Hannah [School; Li, Mi [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; UT−ORNL; Sykes, Robert W. [National Renewable Energy Laboratory, U.S. Department of Energy, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Brown, Steven D. [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; Davison, Brian [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; Tuskan, Gerald A. [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; Pu, Yunqiao [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; UT−ORNL; Ragauskas, Arthur J. [BioEnergy; amp, Center for BioEnergy Innovation, Biosciences; UT−ORNL; Department; amp, Center for Renewable

2017-12-27

Lignin S/G ratio has been investigated as an important factor in biomass recalcitrance to bioethanol production. Because of the complexity and variety of biomass, recalcitrance was also reportedly influenced by several other factors, such as total lignin content, degree of cellulose polymerization, etc. In addition, the effect of S/G ratio on biomass conversion is not uniform across plant species. Herein, 11 Populus trichocarpa natural variants grown under the same conditions with similar total lignin content were selected to minimize the effects of other factors. The lignin S/G ratio of the selected P. trichocarpa natural variants showed negative correlations with p-hydroxybenzoate (PB) and ..beta..-5 linkage contents, while it had positive ones with ..beta..-O-4 linkage, lignin molecular weight, and ethanol production. This study showed the importance of lignin S/G ratio as an independent recalcitrance factor that may aid future energy crop engineering and biomass conversion strategies.

Materials and mechanisms of hole superconductivity

Energy Technology Data Exchange (ETDEWEB)

Hirsch, J.E., E-mail: jhirsch@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319 (United States)

2012-01-15

We study the applicability of the model of hole superconductivity to materials. Both conventional and unconventional materials are considered. Many different classes of materials are discussed. The theory is found suitable to describe all of them. No other theory of superconductivity can describe all these classes of materials. The theory of hole superconductivity proposes that there is a single mechanism of superconductivity that applies to all superconducting materials. This paper discusses several material families where superconductivity occurs and how they can be understood within this theory. Materials discussed include the elements, transition metal alloys, high T{sub c} cuprates both hole-doped and electron-doped, MgB{sub 2}, iron pnictides and iron chalcogenides, doped semiconductors, and elements under high pressure.

Molybdenum-rhenium superconducting suspended nanostructures

Energy Technology Data Exchange (ETDEWEB)

Aziz, Mohsin; Christopher Hudson, David; Russo, Saverio [Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF (United Kingdom)

2014-06-09

Suspended superconducting nanostructures of MoRe 50%/50% by weight are fabricated employing commonly used fabrication steps in micro- and nano-meter scale devices followed by wet-etching with Hydro-fluoric acid of a SiO{sub 2} sacrificial layer. Suspended superconducting channels as narrow as 50 nm and length 3 μm have a critical temperature of ≈6.5 K, which can increase by 0.5 K upon annealing at 400 °C. A detailed study of the dependence of the superconducting critical current and critical temperature upon annealing and in devices with different channel widths reveals that desorption of contaminants is responsible for the improved superconducting properties. These findings pave the way for the development of superconducting electromechanical devices using standard fabrication techniques.

Reactor Power Meter type SG-8

Energy Technology Data Exchange (ETDEWEB)

Glowacki, S W

1981-01-01

The report describes the principle and electronic circuits of the Reactor Power Meter type SG-8. The gamma radiation caused by the activity of the reactor first cooling circuit affectes the ionization chamber being the detector of the instrument. The output detector signal direct current is converted into the frequency of electric pulses by means of the current-to-frequency converter. The output converter frequency is measured by the digital frequency meter: the number of measured digits in time unit is proportional to the reactor power.

SG39 Deliverables. Comments on Covariance Data

International Nuclear Information System (INIS)

Yokoyama, Kenji

2015-01-01

The covariance matrix of a scattered data set, x_i (i=1,n), must be symmetric and positive-definite. As one of WPEC/SG39 contributions to the SG40/CIELO project, several comments or recommendations on the covariance data are described here from the viewpoint of nuclear-data users. To make the comments concrete and useful for nuclear-data evaluators, the covariance data of the latest evaluated nuclear data library, JENDL-4.0 and ENDF/B-VII.1 are treated here as the representative materials. The surveyed nuclides are five isotopes that are most important for fast reactor application. The nuclides, reactions and energy regions dealt with are followings: Pu-239: fission (2.5∼10 keV) and capture (2.5∼10 keV), U-235: fission (500 eV∼10 keV) and capture (500 eV∼30 keV), U-238: fission (1∼10 MeV), capture (below 20 keV, 20∼150 keV), inelastic (above 100 keV) and elastic (above 20 keV), Fe-56: elastic (below 850 keV) and average scattering cosine (above 10 keV), and, Na-23: capture (600 eV∼600 keV), inelastic (above 1 MeV) and elastic (around 2 keV)

Superconducting RF activities at Cornell University

International Nuclear Information System (INIS)

Kirchgessner, J.; Moffat, D.; Padamsee, H.; Rubin, D.; Sears, J.; Shu, Q.S.

1990-01-01

This paper outlines the RF superconductivity research and development work that has taken place at Cornell Laboratory of Nuclear Studies over the past years. The work that has been performed since the last RF superconductivity workshop is emphasized together with a discussion of the direction of future efforts. Past work is summarized first, focusing on research and development activities in the area of RF superconductivity. Superconducting TeV linear collider is then discussed focusing on the application of superconducting RF to a future TeV linear collider. Linear collider structure development is then described centering on the development of a simpler (thereby cheaper) structure for a TeV linear collider. B-factory with superconducting RF is outlined focusing on the formulation of a conceptual design for a B-factory. B-factory structure development is discussed in relation to the advancement in the capability of SC cavities to carry beam currents of several amperes necessary for a high luminosity storage ring. High gradients are discussed as the key to the realization of a high energy superconducting linac or a superconducting RF B-factory. (N.K.)

Frontiers in Superconducting Materials

CERN Document Server

Narlikar, Anant V

2005-01-01

Frontiers in Superconducting Materials gives a state-of-the-art report of the most important topics of the current research in superconductive materials and related phenomena. It comprises 30 chapters written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students. It also addresses electronic and electrical engineers. Even non-specialists interested in superconductivity might find some useful answers.

Superconductivity in the actinides

International Nuclear Information System (INIS)

Smith, J.L.; Lawson, A.C.

1985-01-01

The trends in the occurrence of superconductivity in actinide materials are discussed. Most of them seem to show simple transition metal behavior. However, the superconductivity of americium proves that the f electrons are localized in that element and that ''actinides'' is the correct name for this row of elements. Recently the superconductivity of UBe 13 and UPt 3 has been shown to be extremely unusual, and these compounds fall in the new class of compounds now known as heavy fermion materials

Detecting small gravity change in field measurement: simulations and experiments of the superconducting gravimeter—iGrav

International Nuclear Information System (INIS)

Kao, Ricky; Kabirzadeh, Hojjat; Kim, Jeong Woo; Neumeyer, Juergen; Sideris, Michael G

2014-01-01

In order to detect small gravity changes in field measurements, such as with CO 2  storage, we designed simulations and experiments to validate the capabilities of the iGrav superconducting gravimeter. Qualified data processing was important to obtain the residual gravity from the iGrav's raw gravity signals, without the tidal components, atmosphere, polar motion and hydrological effects. Two simulations and four designed experiments are presented in this study. The first simulation detected the gravity change during CO 2  injection. The residual gravity of CO 2  leakage was targeted with the second simulation from the main storage reservoir to secondary space underground. The designed experiments monitored the situation of gravity anomalies in the iGrav's records. These tests focused on short-term gravity anomalies, such as gravity changes, step functions, repeat observations and gradient measurements from the iGrav, rather than on long-term tidal effects. The four laboratory experiments detected a decrease in gravity of −0.56 ± 0.15 µGal (10 −8  m s −2 ) with a 92.8 kg weight on the top of the iGrav. A step function occurred in the gravity signals, when the tilt control was out of balance. We also used a professional camera dolly with a track to observe repeated horizontal movements and an electric lift table for controlled vertical movements to measure the average gradient of −2.67 ± 0.01 µGal cm −1 . (paper)

Superconducting rotating machines

International Nuclear Information System (INIS)

Smith, J.L. Jr.; Kirtley, J.L. Jr.; Thullen, P.

1975-01-01

The opportunities and limitations of the applications of superconductors in rotating electric machines are given. The relevant properties of superconductors and the fundamental requirements for rotating electric machines are discussed. The current state-of-the-art of superconducting machines is reviewed. Key problems, future developments and the long range potential of superconducting machines are assessed

Status of superconducting power transformer development

Energy Technology Data Exchange (ETDEWEB)

Johnson, R.C.; McConnell, B.W.; Mehta, S.P. [and others

1996-03-01

Development of the superconducting transformer is arguably the most difficult of the ac power applications of superconductivity - this is because of the need for very low ac losses, adequate fault and surge performance, and the rigors of the application environment. This paper briefly summarizes the history of superconducting transformer projects, reviews the key issues for superconducting transformers, and examines the status of HTS transformer development. Both 630-kVA, three-phase and 1-MVA single phase demonstration units are expected to operate in late 1996. Both efforts will further progress toward the development of economical and performance competitive superconducting transformers.

Superconductive analogue of spin glasses

International Nuclear Information System (INIS)

Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

1987-07-01

The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

Quenches in large superconducting magnets

International Nuclear Information System (INIS)

Eberhard, P.H.; Alston-Garnjost, M.; Green, M.A.; Lecomte, P.; Smits, R.G.; Taylor, J.D.; Vuillemin, V.

1977-08-01

The development of large high current density superconducting magnets requires an understanding of the quench process by which the magnet goes normal. A theory which describes the quench process in large superconducting magnets is presented and compared with experimental measurements. The use of a quench theory to improve the design of large high current density superconducting magnets is discussed

Development of superconducting wind turbine generators

DEFF Research Database (Denmark)

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

2013-01-01

In this paper, the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors; one is based on high temperature superconductors......; and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are, however, not without their challenges. The superconductors have to be cooled down to somewhere...

Development of Superconducting Wind Turbine Generators

DEFF Research Database (Denmark)

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

2012-01-01

In this paper the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors (LTS); one is based on high temperature superconductors...... (HTS); and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are however not without their challenges. The superconductors have to be cooled down...

Superconducting fault current-limiter with variable shunt impedance

Science.gov (United States)

Llambes, Juan Carlos H; Xiong, Xuming

2013-11-19

A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

Superconducting magnetic energy storage and superconducting self-supplied electromagnetic launcher

Science.gov (United States)

Ciceron, Jérémie; Badel, Arnaud; Tixador, Pascal

2017-10-01

Superconductors can be used to build energy storage systems called Superconducting Magnetic Energy Storage (SMES), which are promising as inductive pulse power source and suitable for powering electromagnetic launchers. The second generation of high critical temperature superconductors is called coated conductors or REBCO (Rare Earth Barium Copper Oxide) tapes. Their current carrying capability in high magnetic field and their thermal stability are expanding the SMES application field. The BOSSE (Bobine Supraconductrice pour le Stockage d'Energie) project aims to develop and to master the use of these superconducting tapes through two prototypes. The first one is a SMES with high energy density. Thanks to the performances of REBCO tapes, the volume energy and specific energy of existing SMES systems can be surpassed. A study has been undertaken to make the best use of the REBCO tapes and to determine the most adapted topology in order to reach our objective, which is to beat the world record of mass energy density for a superconducting coil. This objective is conflicting with the classical strategies of superconducting coil protection. A different protection approach is proposed. The second prototype of the BOSSE project is a small-scale demonstrator of a Superconducting Self-Supplied Electromagnetic Launcher (S3EL), in which a SMES is integrated around the launcher which benefits from the generated magnetic field to increase the thrust applied to the projectile. The S3EL principle and its design are presented. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2016)", edited by Adel Razek

Stabilized superconducting materials and fabrication process

International Nuclear Information System (INIS)

Chevallier, B.; Dance, J.M.; Etourneau, J.; Lozano, L.; Tressaud, A.; Tournier, R.; Sulpice, A.; Chaussy, J.; Lejay, P.

1989-01-01

Superconducting ceramics are fluorinated at a temperature ≤ 120 0 C. Are also claimed new superconducting materials with a fluorine concentration gradient decreasing from the surface to the core. Superconductivity is stabilized and/or improved [fr

Superconductivity in MgB{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Muranaka, Takahiro; Akimitsu, Jun [Aoyama Gakuin Univ., Kanagawa (Japan). Dept. of Physics and Mathematics

2011-07-01

We review superconductivity in MgB{sub 2} in terms of crystal and electronic structure, electron-phonon coupling, two-gap superconductivity and application. Finally, we introduce the development of new superconducting materials in related compounds. (orig.)

Superconducting materials and magnets

International Nuclear Information System (INIS)

1991-04-01

The Technical Committee Meeting on Superconducting Materials and Magnets was convened by the IAEA and held by invitation of the Japanese government on September 4-6, 1989 in Tokyo. The meeting was hosted by the National Research Institute for Metals. Topics of the conference related to superconducting magnets and technology with particular application to fusion and the superconducting supercollider. Technology using both high and low-temperature superconductors was discussed. This document is a compendium of the papers presented at the meeting. Refs, figs and tabs

Superconducting self-correcting harmonic coils for pulsed superconducting dipole or multipole magnets

International Nuclear Information System (INIS)

Dael, A.; Kircher, F.; Perot, J.

1975-01-01

Due to the zero resistance of a superconducting wire, an induced current in a closed superconducting circuit is continuously exactly opposed to its cause. This phenomenon was applied to the correction of the field harmonics of a pulsed magnet by putting short-circuited superconducting coils of particular symmetry in the useful aperture of the magnet. After a review of the main characteristics of such devices, the construction of two correcting coils (quadrupole and sextupole) is described. Experimental results of magnetic efficiency and time behavior are given; they are quite encouraging, since the field harmonics were reduced by one or two orders of magnitude

Development of superconducting ship propulsion system

International Nuclear Information System (INIS)

Sakuraba, Junji; Mori, Hiroyuki; Hata, Fumiaki; Sotooka, Koukichi

1991-01-01

When we plan displacement-type monohull high speed vessels, it is difficult to get the hull form with the wave-making resistance minimum, because the stern shape is restricted by arrangement of propulsive machines and shafts. A small-sized and light-weight propulsive machines will reduce the limit to full form design. Superconducting technology will have capability of realizing the small-sized and light-weight propulsion motor. The superconducting electric propulsion system which is composed of superconducting propulsion motors and generators, seems to be an ideal propulsion system for future vehicles. We have constructed a 480 kW superconducting DC homopolar laboratory test motor for developing this propulsion system. The characteristic of this motor is that it has a superconducting field winding and a segmented armature drum. The superconducting field winding which operates in the persistent current mode, is cooled by a condensation heat exchanger and helium refigerating system built into the cryostat of the superconducting field winding. The operating parameters of this motor agreed well with the design parameters. Using the design concepts of this motor, we have conceptually designed a 150,000-200,000 PS superconducting electric propulsive system for a displacement-type monohull high speed ship. (author)

Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

International Nuclear Information System (INIS)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo; Min, Kyong Mahn

2013-01-01

In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG tubes

Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

Energy Technology Data Exchange (ETDEWEB)

Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [Korea Hydro and Nuclear Power Co. Ltd, Daejeon (Korea, Republic of); Min, Kyong Mahn [Universal Monitoring and Inspection Inc., Daejeon (Korea, Republic of)

2013-10-15

In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG

Superconductivity Engineering and Its Application for Fusion 3.Superconducting Technology as a Gateway to Future Technology

Science.gov (United States)

Asano, Katsuhiko

Hopes for achieving a new source of energy through nuclear fusion rest on the development of superconducting technology that is needed to make future equipments more energy efficient as well as increase their performance. Superconducting technology has made progress in a wide variety of fields, such as energy, life science, electronics, industrial use and environmental improvement. It enables the actualization of equipment that was unachievable with conventional technology, and will sustain future “IT-Based Quality Life Style”, “Sustainable Environmental” and “Advanced Healthcare” society. Besides coil technology with high magnetic field performance, superconducting electoronics or device technology, such as SQUID and SFQ-circuit, high temperature superconducting material and advanced cryogenics technology might be great significance in the history of nuclear fusion which requires so many wide, high and ultra technology. Superconducting technology seems to be the catalyst for a changing future society with nuclear fusion. As society changes, so will superconducting technology.

Superconductivity in doped insulators

International Nuclear Information System (INIS)

Emery, V.J.; Kivelson, S.A.

1995-01-01

It is shown that many synthetic metals, including high temperature superconductors are ''bad metals'', with such a poor conductivity that the usual meanfield theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. It is argued that the supression of a first order phase transition (phase separation) by the long-range Coulomb interaction leads to high temperature superconductivity accompanied by static or dynamical charge inhomogeneIty. Evidence in support of this picture for high temperature superconductors is described

Development of superconducting equipment for fusion device

International Nuclear Information System (INIS)

Konno, Masayuki; Ueda, Toshio; Hiue, Hisaaki; Ohgushi, Kouzou

1993-01-01

At Fuji Electric Co., Ltd., the development of superconductivity was started from 1960, and superconducting equipment for fusion device has been developed for ten years. The superconducting equipment, which is developed for fusion by Fuji Electric Co., Ltd., are able to be grouped in three categories which are current lead, superconducting coil and superconducting bus-line. The current lead is an electrical feeder between a superconducting coil and an electrical power supply. The rated current of developed current lead is 30kA at continuous use and 100kA at short time use respectively. The advanced disk type coil is developed for the toroidal field coil and some coils are developed for critical current measurement. Superconductor is applied to the superconducting bus-line between the superconducting coils and the current leads, and the bus-line is being developed for the Large Helical Device. This report describes an abstract of these equipment. (author)

Superconducting magnets technologies for large accelerator

International Nuclear Information System (INIS)

Ogitsu, Toru

2017-01-01

The first hadron collider with superconducting magnet technologies was built at Fermi National Accelerator Laboratory as TEVATRON. Since then, the superconducting magnet technologies are widely used in large accelerator applications. The paper summarizes the superconducting magnet technologies used for large accelerators. (author)

Meissner effect in superconducting microtraps

International Nuclear Information System (INIS)

Cano, Daniel

2009-01-01

This thesis investigates the impact of the Meissner effect on magnetic microtraps for ultracold atoms near superconducting microstructures. This task has been accomplished both theoretically and experimentally. The Meissner effect distorts the magnetic fields near superconducting surfaces, thus altering the parameters of magnetic microtraps. Both computer simulations and experimental measurements demonstrate that the Meissner effect shortens the distance between the magnetic microtrap and the superconducting surface, reduces the magnetic-field gradients and dramatically lowers the trap depth. A novel numerical method for calculating magnetic fields in atom chips with superconducting microstructures has been developed. This numerical method overcomes the geometrical limitations of other calculation techniques and can solve superconducting microstructures of arbitrary geometry. The numerical method has been used to calculate the parameters of magnetic microtraps in computer-simulated chips containing thin-film wires. Simulations were carried out for both the superconducting and the normal-conducting state, and the differences between the two cases were analyzed. Computer simulations have been contrasted with experimental measurements. The experimental apparatus generates a magnetic microtrap for ultracold Rubidium atoms near a superconducting Niobium wire of circular cross section. The design and construction of the apparatus has met the challenge of integrating the techniques for producing atomic quantum gases with the techniques for cooling solid bodies to cryogenic temperatures. By monitoring the position of the atom cloud, one can observe how the Meissner effect influences the magnetic microtrap. (orig.)

Meissner effect in superconducting microtraps

Energy Technology Data Exchange (ETDEWEB)

Cano, Daniel

2009-04-30

This thesis investigates the impact of the Meissner effect on magnetic microtraps for ultracold atoms near superconducting microstructures. This task has been accomplished both theoretically and experimentally. The Meissner effect distorts the magnetic fields near superconducting surfaces, thus altering the parameters of magnetic microtraps. Both computer simulations and experimental measurements demonstrate that the Meissner effect shortens the distance between the magnetic microtrap and the superconducting surface, reduces the magnetic-field gradients and dramatically lowers the trap depth. A novel numerical method for calculating magnetic fields in atom chips with superconducting microstructures has been developed. This numerical method overcomes the geometrical limitations of other calculation techniques and can solve superconducting microstructures of arbitrary geometry. The numerical method has been used to calculate the parameters of magnetic microtraps in computer-simulated chips containing thin-film wires. Simulations were carried out for both the superconducting and the normal-conducting state, and the differences between the two cases were analyzed. Computer simulations have been contrasted with experimental measurements. The experimental apparatus generates a magnetic microtrap for ultracold Rubidium atoms near a superconducting Niobium wire of circular cross section. The design and construction of the apparatus has met the challenge of integrating the techniques for producing atomic quantum gases with the techniques for cooling solid bodies to cryogenic temperatures. By monitoring the position of the atom cloud, one can observe how the Meissner effect influences the magnetic microtrap. (orig.)

The energizing of a NMR superconducting coil by a superconducting rectifier

International Nuclear Information System (INIS)

Sikkenga, J.; ten Kate, H.H.J.; van der Klundert, L.J.M.; Knoben, J.; Kraaij, G.J.; Spuorenberg, C.J.G.

1985-01-01

NMR magnets require a good homogeneity within a certain volume and an excellent field stability. The homogeneity can be met using a superconducting shim coil system. The field stability requires a constant current, although in many cases the current decay time constant is too low, due to imperfections in the superconducting wire and joints. This can be overcome using a rectifier. The rectifier can also be used to load the coil. The combination and interaction of the superconducting NMR coil (2.0 Tesla and 0.35 m cold bore) and the rectifier (20 W / 1 kA) is tested. The safety of the system is discussed. The shim coil system can compensate the strayfield of the rectifier. The field decay compensation will be discussed

Liquid phase sintered superconducting cermet

International Nuclear Information System (INIS)

Ray, S.P.

1990-01-01

This patent describes a method of making a superconducting cermet having superconducting properties with improved bulk density, low porosity and in situ stabilization. It comprises: forming a structure of a superconducting ceramic material having the formula RM 2 Cu 3 O (6.5 + x) wherein R is one or more rare earth elements capable of reacting to form a superconducting ceramic, M is one or more alkaline earth metal elements selected from barium and strontium capable of reacting to form a superconducting ceramic, x is greater than 0 and less than 0.5; and a precious metal compound in solid form selected from the class consisting of oxides, sulfides and halides of silver; and liquid phase sintering the mixture at a temperature wherein the precious metal of the precious metal compound is molten and below the melting point of the ceramic material. The liquid phase sintering is carried out for a time less than 36 hours but sufficient to improve the bulk density of the cermet

Japan. Superconductivity for Smart Grids

Energy Technology Data Exchange (ETDEWEB)

Hayakawa, K.

2012-11-15

Currently, many smart grid projects are running or planned worldwide. These aim at controlling the electricity supply more efficiently and more stably in a new power network system. In Japan, especially superconductivity technology development projects are carried out to contribute to the future smart grid. Japanese cable makers such as Sumitomo Electric and Furukawa Electric are leading in the production of high-temperature superconducting (HTS) power cables. The world's largest electric current and highest voltage superconductivity proving tests have been started this year. Big cities such as Tokyo will be expected to introduce the HTS power cables to reduce transport losses and to meet the increased electricity demand in the near future. Superconducting devices, HTS power cables, Superconducting Magnetic Energy Storage (SMES) and flywheels are the focus of new developments in cooperations between companies, universities and research institutes, funded by the Japanese research and development funding organization New Energy and Industrial Technology Development Organization (NEDO)

Low-velocity superconducting accelerating structures

International Nuclear Information System (INIS)

Delayen, J.R.

1990-01-01

The present paper reviews the status of RF superconductivity as applied to low-velocity accelerating properties. Heavy-ion accelerators must accelerate efficiently particles which travel at a velocity much smaller than that of light particles, whose velocity changes along accelerator, and also different particles which have different velocity profiles. Heavy-ion superconducting accelerators operate at frequencies which are lower than high-energy superconducting accelerators. The present paper first discusses the basic features of heavy-ion superconducting structures and linacs. Design choices are then addressed focusing on structure geometry, materials, frequency, phase control, and focusing. The report also gives an outline of the status of superconducting booster projects currently under way at the Argonne National Laboratory, SUNY Stony Brook, Weizmann Institute, University of Washington, Florida State, Saclay, Kansas State, Daresbury, Japanese Atomic Energy Research Institute, Legnaro, Bombay, Sao Paulo, ANU (Canberra), and Munich. Recent developments and future prospects are also described. (N.K.) 68 refs

Superconducting cyclotrons

International Nuclear Information System (INIS)

Blosser, H.G.; Johnson, D.A.; Burleigh, R.J.

1976-01-01

Superconducting cyclotrons are particularly appropriate for acceleration of heavy ions. A review is given of design features of a superconducting cyclotron with energy 440 (Q 2 /A) MeV. A strong magnetic field (4.6 tesla average) leads to small physical size (extraction radius 65 cm) and low construction costs. Operating costs are also low. The design is based on established technology (from present cyclotrons and from large bubble chambers). Two laboratories (in Chalk River, Canada and in East Lansing, Michigan) are proceeding with construction of full-scale prototype components for such cyclotrons

Superconducting phase transition in STM tips

Energy Technology Data Exchange (ETDEWEB)

Eltschka, Matthias; Jaeck, Berthold; Assig, Maximilian; Etzkorn, Markus; Ast, Christian R. [Max Planck Institute for Solid State Research, Stuttgart (Germany); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); Ecole Polytechnique Federale de Lausanne (Switzerland)

2015-07-01

The superconducting properties of systems with dimensions comparable to the London penetration depth considerably differ from macroscopic systems. We have studied the superconducting phase transition of vanadium STM tips in external magnetic fields. Employing Maki's theory we extract the superconducting parameters such as the gap or the Zeeman splitting from differential conductance spectra. While the Zeeman splitting follows the theoretical description of a system with s=1/2 and g=2, the superconducting gaps as well as the critical fields depend on the specific tip. For a better understanding of the experimental results, we solve a one dimensional Usadel equation modeling the superconducting tip as a cone with the opening angle α in an external magnetic field. We find that only a small region at the apex of the tip is superconducting in high magnetic fields and that the order of the phase transition is directly determined by α. Further, the spectral broadening increases with α indicating an intrinsic broadening mechanism due to the conical shape of the tip. Comparing these calculations to our experimental results reveals the order of the superconducting phase transition of the STM tips.

Sample of superconducting wiring (Niobium Titanium)

CERN Multimedia

About NbTi cable: The cable consists of 36 strands of superconducting wire, each strand has a diameter of 0.825 mm and houses 6300 superconducting filaments of niobium-titanium (Nb-Ti, a superconducting alloy). Each filament has a diameter of about 0.006 mm, i.e. 10 times smaller than a typical human hair. The filaments are embedded in a high-purity copper matrix. Copper is a normal conducting material. The filaments are in the superconductive state when the temperature is below about -263ºC (10.15 K). When the filaments leave the superconductive state, the copper acts as conductor transports the electrical current. Each strand of The NbTi cable (at superconducting state) has a current density of up to above 2000 A/mm2 at 9 T and -271ºC (2.15 K). A cable transport a current of about 13000 A at 10 T and -271ºC (2.15 K). About LHC superconducting wiring: The high magnetic fields needed for the LHC can only be reached using superconductors. At very low temperatures, superconductors have no electrical resistan...

Sample of superconducting wiring (Niobium Titanium)

CERN Multimedia

About NbTi cable: The cable consists of 36 strands of superconducting wire, each strand has a diameter of 0.825 mm and houses 6300 superconducting filaments of niobium-titanium (Nb-Ti, a superconducting alloy). Each filament has a diameter of about 0.006 mm, i.e. 10 times smaller than a typical human hair. The filaments are embedded in a high-purity copper matrix. Copper is a normal conducting material. The filaments are in the superconductive state when the temperature is below about -263ºC (10.15 K). When the filaments leave the superconductive state, the copper acts as conductor transports the electrical current. Each strand of The NbTi cable (at superconducting state) has a current density of up to above 2000 A/mm2 at 9 T and -271ºC (2.15 K). A cable transport a current of about 13000 A at 10 T and -271ºC (2.15 K). About LHC superconducting wiring: The high magnetic fields needed for the LHC can only be reached using superconductors. At very low temperatures, superconductors have no electrical resista...

Mitigation of corrosion product ingress into SG's

International Nuclear Information System (INIS)

Han, S.H.

1988-01-01

Design and operation experiences to mitigate corrosion product ingress into SGs in Korea nuclear power plants are briefly reviewed. Maintaining the feedwater pH above 9.6 with morpholine seems to contribute significantly to reduction of iron transport to SGs. Measured iron transport rates were 4.8 g/hr/100 MWe at pH 9.8 and 2.8 g/hr/100 MWe at 9.3, respectively. Removal of corrosion products through SG blowdown is very limited. Its removal efficiency at the higher pH plant was in the neighborhood of 10 %. In one of the Korea Nuclear Units, a large amount of sludge piles were found in the middle of tube bundles especially on the cold leg side. Damaged tubes were identified by the multi-frequency eddy current tests and plugged later during the refueling period. Intermittent blowdown-rate increase was tried to enhance ionic impurity removal through SG blowdown. Even though it was not effective against Na, removal other impurity was improved, resulting in prolonged condensate polisher operation periods by 1 - 2 days. Two-bed polisher design, a cation bed followed by a mixed bed, was chosen for future PWR plants to enhance corrosion product filtering capability of the polishers. Condensate pump discharge polishing and divided hot well polishing methods are currently in consideration. (Nogami, K.)

Superconducting quantum circuits theory and application

Science.gov (United States)

Deng, Xiuhao

Superconducting quantum circuit models are widely used to understand superconducting devices. This thesis consists of four studies wherein the superconducting quantum circuit is used to illustrate challenges related to quantum information encoding and processing, quantum simulation, quantum signal detection and amplification. The existence of scalar Aharanov-Bohm phase has been a controversial topic for decades. Scalar AB phase, defined as time integral of electric potential, gives rises to an extra phase factor in wavefunction. We proposed a superconducting quantum Faraday cage to detect temporal interference effect as a consequence of scalar AB phase. Using the superconducting quantum circuit model, the physical system is solved and resulting AB effect is predicted. Further discussion in this chapter shows that treating the experimental apparatus quantum mechanically, spatial scalar AB effect, proposed by Aharanov-Bohm, can't be observed. Either a decoherent interference apparatus is used to observe spatial scalar AB effect, or a quantum Faraday cage is used to observe temporal scalar AB effect. The second study involves protecting a quantum system from losing coherence, which is crucial to any practical quantum computation scheme. We present a theory to encode any qubit, especially superconducting qubits, into a universal quantum degeneracy point (UQDP) where low frequency noise is suppressed significantly. Numerical simulations for superconducting charge qubit using experimental parameters show that its coherence time is prolong by two orders of magnitude using our universal degeneracy point approach. With this improvement, a set of universal quantum gates can be performed at high fidelity without losing too much quantum coherence. Starting in 2004, the use of circuit QED has enabled the manipulation of superconducting qubits with photons. We applied quantum optical approach to model coupled resonators and obtained a four-wave mixing toolbox to operate photons

Superconducting tin core fiber

International Nuclear Information System (INIS)

Homa, Daniel; Liang, Yongxuan; Hill, Cary; Kaur, Gurbinder; Pickrell, Gary

2015-01-01

In this study, we demonstrated superconductivity in a fiber with a tin core and fused silica cladding. The fibers were fabricated via a modified melt-draw technique and maintained core diameters ranging from 50-300 microns and overall diameters of 125-800 microns. Superconductivity of this fiber design was validated via the traditional four-probe test method in a bath of liquid helium at temperatures on the order of 3.8 K. The synthesis route and fiber design are perquisites to ongoing research dedicated all-fiber optoelectronics and the relationships between superconductivity and the material structures, as well as corresponding fabrication techniques. (orig.)

ESCAR superconducting magnet system

International Nuclear Information System (INIS)

Gilbert, W.S.; Meuser, R.B.; Pope, W.L.; Green, M.A.

1975-01-01

Twenty-four superconducting dipoles, each about 1 meter long, provide the guide field for the Experimental Superconducting Accelerator Ring proton accelerator--storage ring. Injection of 50 MeV protons corresponds to a 3 kG central dipole field, and a peak proton energy of 4.2 GeV corresponds to a 46 kG central field. Thirty-two quadrupoles provide focusing. The 56 superconducting magnets are contained in 40 cryostats that are cryogenically connected in a novel series ''weir'' arrangement. A single 1500 W refrigeration plant is required. Design and testing of the magnet and cryostat system are described. (U.S.)

High-$T_{c}$ superconductivity

CERN Document Server

Ott, Hans Rudolf

1996-01-01

Previously, motivation for enhanced b -> sg from new flavor physics has centered on discrepancies between theory and experiment. Here two experimental hints are considered: (1) updated measurements of the charm multiplicity and BR(Bbar -> X_{ccbars}) at the Upsilon (4S) imply BR(B -> Xnocharm}) \\approx 12.4 \\pm 5.6 %, (2) the Bbar} -> K- X and Bbar -> K+/K- X branching fractions are in excess of conventional Bbar -> Xc -> KX yields by about 16.9 \\pm 5.6 % and 18 \\pm 5.3 %, respectively. JETSET 7.4 was used to estimate kaon yields from ssbar popping in Bbar -> Xcubard decays. JETSET 7.4 Monte Carlos for BR(Bbar -> Xsg) \\sim 15 % imply that the additional kaon production would lead to 1 \\sigma agreement with observed charged and neutral kaon yields. The Ks momentum spectrum would be consistent with recent CLEO bounds in the end point region. Search strategies for enhanced b -> sg are discussed in light of large theoretical uncertainty in the standard model fast kaon background from b -> s penguin operators.

Superconducting six-axis accelerometer

Science.gov (United States)

Paik, H. J.

1990-01-01

A new superconducting accelerometer, capable of measuring both linear and angular accelerations, is under development at the University of Maryland. A single superconducting proof mass is magnetically levitated against gravity or any other proof force. Its relative positions and orientations with respect to the platform are monitored by six superconducting inductance bridges sharing a single amplifier, called the Superconducting Quantum Interference Device (SQUID). The six degrees of freedom, the three linear acceleration components and the three angular acceleration components, of the platform are measured simultaneously. In order to improve the linearity and the dynamic range of the instrument, the demodulated outputs of the SQUID are fed back to appropriate levitation coils so that the proof mass remains at the null position for all six inductance bridges. The expected intrinsic noise of the instrument is 4 x 10(exp -12)m s(exp -2) Hz(exp -1/2) for linear acceleration and 3 x 10(exp -11) rad s(exp -2) Hz(exp -1/2) for angular acceleration in 1-g environment. In 0-g, the linear acceleration sensitivity of the superconducting accelerometer could be improved by two orders of magnitude. The design and the operating principle of a laboratory prototype of the new instrument is discussed.

Superconductivity

International Nuclear Information System (INIS)

Narlikar, A.V.

1993-01-01

Amongst the numerous scientific discoveries that the 20th century has to its credit, superconductivity stands out as an exceptional example of having retained its original dynamism and excitement even for more than 80 years after its discovery. It has proved itself to be a rich field by continually offering frontal challenges in both research and applications. Indeed, one finds that a majority of internationally renowned condensed matter theorists, at some point of their career, have found excitement in working in this important area. Superconductivity presents a unique example of having fetched Nobel awards as many as four times to date, and yet, interestingly enough, the field still remains open for new insights and discoveries which could undeniably be of immense technological value. 1 fig

On anyon superconductivity--

International Nuclear Information System (INIS)

Chen, Y.-H.; Wilczek, F.; Witten, E.; Halperin, B.I.

1989-01-01

We investigate the statistical mechanics of a gas of fractional statistics particles in 2 + 1 dimensions. In the case of statistics very close to Fermi statistics (statistical parameter θ = π(1 - 1/n), for large n), the effect of the statistics is a weak attraction. Building upon earlier RPA calculation for the case n = 2, the authors argue that for large n perturbation theory is reliable and exhibits superfluidity (or superconductivity after coupling to electromagnetism). They describe the order parameter for this superconductng phase in terms of spontaneous breaking of commutativity of translations as opposed to the usual pairing order parameters. The vortices of the superconducting anyon gas are charged, and superconducting order parameters of the usual type vanish. They investigate the characteristic P and T violating phenomenology

Radiation effects on superconductivity

International Nuclear Information System (INIS)

Brown, B.S.

1975-01-01

The effect of radiation on the superconducting transition temperature (T/sub c/), upper critical field (H/sub c2/), and volume-pinning-force density (F/sub p/) were discussed for the three kinds of superconducting material (elements, alloys, and compounds). 11 figures, 3 tables, 86 references

Superconductivity in borides and carbides

International Nuclear Information System (INIS)

Muranaka, Takahiro

2007-01-01

It was thought that intermetallic superconductors do not exhibit superconductivity at temperatures over 30 K because of the Bardeen-Cooper-Schrieffer (BCS) limit; therefore, researchers have been interested in high-T c cuprates. Our group discovered high-T c superconductivity in MgB 2 at 39 K in 2001. This discovery has initiated a substantial interest in the potential of high-T c superconductivity in intermetallic compounds that include 'light' elements (borides, carbides, etc.). (author)

Superconductivity and magnet technology

International Nuclear Information System (INIS)

Lubell, M.S.

1975-01-01

The background theory of superconducting behavior is reviewed. Three parameters that characterize superconducting materials with values of commercial materials as examples are discussed. More than 1000 compounds and alloy systems and 26 elements are known to exhibit superconducting properties under normal conditions at very low temperatures. A wide variety of crystal structures are represented among the known superconductors. The most important ones do seem to have cubic symmetry such as the body-centered cubic (NbZr and NbTi), face-centered cubic (NbN), and the A15 or β-tungsten structures (Nb 3 Sn), V 3 Ga, Nb 3 Ge, Nb 3 Al, and V 3 Si). Attempts to understand some of the particular phenomena associated with superconductors as a necessary prelude to constructing superconducting magnets are discussed by the author. The origin of degradation is briefly discussed and methods to stabilize magnets are illustrated. The results of Oak Ridge National Laboratory design studies of toroidal magnet systems for fusion reactors are described

Hybrid superconducting magnetic suspensions

International Nuclear Information System (INIS)

Tixador, P.; Hiebel, P.; Brunet, Y.; Chaud, X.; Gautier-Picard, P.

1996-01-01

Superconductors, especially high T c ones, are the most attractive materials to design stable and fully passive magnetic suspensions which have to control five degrees of freedom. The hybrid superconducting magnetic suspensions present high performances and a simple cooling mode. They consist of a permanent magnet bearing, stabilized by a suitable magnet-superconductor structure. Several designs are given and compared in terms of forces and stiffnesses. The design of the magnet bearing plays an important part. The superconducting magnetic bearing participates less in levitation but must provide a high stabilizing stiffness. This is achieved by the magnet configuration, a good material in term of critical current density and field cooling. A hybrid superconducting suspension for a flywheel is presented. This system consists of a magnet thrust bearing stabilized by superconductors interacting with an alternating polarity magnet structure. First tests and results are reported. Superconducting materials are magnetically melt-textured YBaCuO

A Conceptual Design of Light-weighted Mobile Robot for the Integrity of SG Tubes in NPP

Energy Technology Data Exchange (ETDEWEB)

Seo, Yong Chil; Jeong, Kyung Min; Shin, Ho Chul; Lee, Sung Uk; Cho, Jae Wan; Choi, Young Soo; Kim, Seung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Shin, Chun Sup; Park, Ki Tae [Korea Plant Serviceand Engineering, Busan (Korea, Republic of)

2010-10-15

Steam generators (SG) are among the most critical components of pressurized water Nuclear Power Plants (NPP). SG tubes must provide a reliable pressure boundary between the primary and secondary cooling water. It is because that any leakage from tube defects could result in the release of radioactivity to the environment. Thus degradations of steam generators tubes should be monitored and inspected periodically under nuclear regulatory. In-service inspections of SG tubes are carried out using eddy current test (ECT) and the defected tubes are usually plugged. Because the radioactivity in the internal of SG chambers limits free access of human worker, remote manipulators are required. In South Korea, Manipulators such as the Zetec SM series and the Westinghouse ROSA series have been used. Such manipulators are rigidly mounted to manways or tube sheets of SG. Confusions for the inspected tubes may occur from deflection of the manipulators. To reduce the deflections of the manipulators for covering the large working areas of tube sheets, sufficient rigidity is required and it leads to the increase of the weight. Such weight increase results in some difficulties for handling and more radiation exposure of human workers. Recently light-weighed mobile robots have been introduced by Westinghouse and Zetec. The robots can move keeping in contact with the tube sheets using devices which are commonly called cam-locks. They are easier to handle and provide no confusion for the position of the inspected tubes. But when the clamping forces are loosed accidently, they can be fall down and light repair works can be performed. This paper provides the design results for a light weighted mobile robot which is recently being developed in cooperation of our institutes

A Conceptual Design of Light-weighted Mobile Robot for the Integrity of SG Tubes in NPP

International Nuclear Information System (INIS)

Seo, Yong Chil; Jeong, Kyung Min; Shin, Ho Chul; Lee, Sung Uk; Cho, Jae Wan; Choi, Young Soo; Kim, Seung Ho; Shin, Chun Sup; Park, Ki Tae

2010-01-01

Steam generators (SG) are among the most critical components of pressurized water Nuclear Power Plants (NPP). SG tubes must provide a reliable pressure boundary between the primary and secondary cooling water. It is because that any leakage from tube defects could result in the release of radioactivity to the environment. Thus degradations of steam generators tubes should be monitored and inspected periodically under nuclear regulatory. In-service inspections of SG tubes are carried out using eddy current test (ECT) and the defected tubes are usually plugged. Because the radioactivity in the internal of SG chambers limits free access of human worker, remote manipulators are required. In South Korea, Manipulators such as the Zetec SM series and the Westinghouse ROSA series have been used. Such manipulators are rigidly mounted to manways or tube sheets of SG. Confusions for the inspected tubes may occur from deflection of the manipulators. To reduce the deflections of the manipulators for covering the large working areas of tube sheets, sufficient rigidity is required and it leads to the increase of the weight. Such weight increase results in some difficulties for handling and more radiation exposure of human workers. Recently light-weighed mobile robots have been introduced by Westinghouse and Zetec. The robots can move keeping in contact with the tube sheets using devices which are commonly called cam-locks. They are easier to handle and provide no confusion for the position of the inspected tubes. But when the clamping forces are loosed accidently, they can be fall down and light repair works can be performed. This paper provides the design results for a light weighted mobile robot which is recently being developed in cooperation of our institutes

The EUMETSAT Polar System - Second Generation (EPS-SG) micro-wave imaging (MWI) mission

Science.gov (United States)

Bojkov, B. R.; Accadia, C.; Klaes, D.; Canestri, A.; Cohen, M.

2017-12-01

The EUMETSAT Polar System (EPS) will be followed by a second generation system called EPS-SG. This new family of missions will contribute to the Joint Polar System being jointly set up with NOAA in the timeframe 2020-2040. These satellites will fly, like Metop (EPS), in a sun synchronous, low earth orbit at 830 km altitude and 09:30 local time descending node, providing observations over the full globe with revisit times of 12 hours. EPS-SG consists of two different satellites configurations, the EPS-SGa series dedicated to IR and MW sounding, and the EPS-SGb series dedicated to microwave imaging and scatterometry. The EPS-SG family will consist of three successive launches of each satellite-type. The Microwave Imager (MWI) will be hosted on Metop-SGb series of satellites, with the primary objective of supporting Numerical Weather Prediction (NWP) at regional and global scales. Other applications will be observation of surface parameters such as sea ice concentration and hydrology applications. The 18 MWI instrument frequencies range from 18.7 GHz to 183 GHz. All MWI channels up to 89 GHz will measure V- and H polarizations. The MWI was also designed to provide continuity of measurements for select heritage microwave imager channels (e.g. SSM/I, AMSR-E). The additional sounding channels such as the 50-55 and 118 GHz bands will provide additional cloud and precipitation information over sea and land. This combination of channels was successfully tested on the NPOESS Aircraft Sounder Testbed - Microwave Sounder (NAST-M) airborne radiometer, and it is the first time that will be implemented in a conical scanning configuration in a single instrument. An overview of the EPS-SG programme and the MWI instrument will be presented.

Development of 50 MVA superconducting generator

International Nuclear Information System (INIS)

Ueda, Kiyotaka; Maki, Naoki; Takahashi, Noriyoshi; Ogata, Hisanao; Sanematsu, Toshihiro.

1984-01-01

Superconducting synchronous generators are expected to be the large capacity turbogenerators of next generation, but they have the structural features considerably different from conventional generators, such as low temperature multiple cylinder rotors and air gap armature winding. For the purpose of grasping the performance of superconducting generators and establishing the fundamental technology for their practical use, Hitachi Ltd. manufactured a 50 MVA superconducting generator. As the results of test, the precooling operation was smoothly finished for about 40 hours, and the superconducting rotor rotated stably at 3000 rpm. The steady and transient electrical characteristics were able to be grasped. It is intended to reflect these results to the development of a practical generator of 500 MVA class expected as the next step. When the superconducting exciting winding cooled by liquid helium is used, the reduction of weight, the improvement of efficiency and the improvement of the stability of power system can be expected. The structural features and the function of superconducting generators, the present state of the development in the world, the outline of the 50 MVA generator, the test results and the problems and the prospect hereafter are reported. The superconducting winding was made of NbTiZr alloy multicore wires. (Kako, I.)

Recent advances in fullerene superconductivity

CERN Document Server

Margadonna, S

2002-01-01

Superconducting transition temperatures in bulk chemically intercalated fulleride salts reach 33 K at ambient pressure and in hole-doped C sub 6 sub 0 derivatives in field-effect-transistor (FET) configurations, they reach 117 K. These advances pose important challenges for our understanding of high-temperature superconductivity in these highly correlated organic metals. Here we review the structures and properties of intercalated fullerides, paying particular attention to the correlation between superconductivity and interfullerene separation, orientational order/disorder, valence state, orbital degeneracy, low-symmetry distortions, and metal-C sub 6 sub 0 interactions. The metal-insulator transition at large interfullerene separations is discussed in detail. An overview is also given of the exploding field of gate-induced superconductivity of fullerenes in FET electronic devices.

Superconductivity in Layered Organic Metals

Directory of Open Access Journals (Sweden)

Jochen Wosnitza

2012-04-01

Full Text Available In this short review, I will give an overview on the current understanding of the superconductivity in quasi-two-dimensional organic metals. Thereby, I will focus on charge-transfer salts based on bis(ethylenedithiotetrathiafulvalene (BEDT-TTF or ET for short. In these materials, strong electronic correlations are clearly evident, resulting in unique phase diagrams. The layered crystallographic structure leads to highly anisotropic electronic as well as superconducting properties. The corresponding very high orbital critical field for in-plane magnetic-field alignment allows for the occurrence of the Fulde–Ferrell– Larkin–Ovchinnikov state as evidenced by thermodynamic measurements. The experimental picture on the nature of the superconducting state is still controversial with evidence both for unconventional as well as for BCS-like superconductivity.

Interplay of magnetism and superconductivity

International Nuclear Information System (INIS)

Akhavan, M.

2006-01-01

After about two decades of intense research since the discovery of high-temperature superconductivity (HTSC) in cuprates, although many aspects of the physics and chemistry of these cuprate superconductors are now well understood, the underlying pairing mechanism remains elusive. Magnetism and superconductivity are usually thought as incompatible, but in number of special materials including HTSCs these two mutually excluding mechanisms are found to coexist. The presence in a system of superconductivity and magnetism, gives rise to a large number of interesting phenomenon. This article provides perspective on recent developments and their implications for our understanding of the interplay between magnetism and superconductivity in new materials. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Gauge Model of High-Tc Superconductivity

International Nuclear Information System (INIS)

Ng, Sze Kui

2012-01-01

A simple gauge model of superconductivity is presented. The seagull vertex term of this gauge model gives an attractive potential between electrons for the forming of Cooper pairs of superconductivity. This gauge model gives a unified description of superconductivity and magnetism including antiferromagnetism, pseudogap phenomenon, stripes phenomenon, paramagnetic Meissner effect, Type I and Type II supeconductivity and high-T c superconductivity. The doping mechanism of superconductivity is found. It is shown that the critical temperature T c is related to the ionization energies of elements and can be computed by a formula of T c . For the high-T c superconductors such as La 2-x Sr x CuO 4 , Y Ba 2 Cu 3 O 7 , and MgB 2 , the computational results of T c agree with the experimental results.

Superconducting active impedance converter

International Nuclear Information System (INIS)

Ginley, D.S.; Hietala, V.M.; Martens, J.S.

1993-01-01

A transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductors allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10-80 K. temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology. 12 figures

Superconducting linac booster

International Nuclear Information System (INIS)

Srinivasan, B.; Betigeri, M.G.; Pandey, M.K.; Pillay, R.G.; Kurup, M.B.

1997-01-01

The report on superconducting LINAC booster, which is a joint project of Bhabha Atomic Research Centre (BARC) and Tata Institute of Fundamental Research (TIFR), brings out the work accomplished so far towards the development of the technology of superconducting LINAC to boost the energy of ions from the 14UD Pelletron. The LINAC is modular in construction with each module comprising of a helium cryostat housing four lead-plated quarter wave resonators. The resonators are superconducting for temperatures below 7.19K. An energy boost of 2 MeV/q per module is expected to be achieved. The first module and the post-tandem superbuncher have been fabricated and tested on the LINAC beam line. This report gives a summary of the technological achievements and also brings out the difficulties encountered during the R and D phase. (author)

Superconducting super collider

International Nuclear Information System (INIS)

Limon, P.J.

1987-01-01

The Superconducting Super Collider is to be a 20 TeV per beam proton-proton accelerator and collider. Physically the SCC will be 52 miles in circumference and slightly oval in shape. The use of superconducting magnets instead of conventional cuts the circumference from 180 miles to the 52 miles. The operating cost of the SCC per year is estimated to be about $200-250 million. A detailed cost estimate of the project is roughly $3 billion in 1986 dollars. For the big collider ring, the technical cost are dominated by the magnet system. That is why one must focus on the cost and design of the magnets. Presently, the process of site selection is underway. The major R and D efforts concern superconducting dipoles. The magnets use niobium-titanium as a conductor stabilized in a copper matrix. 10 figures

Superconductivity in doped two-leg ladder cuprates

International Nuclear Information System (INIS)

Qin Jihong; Yuan Feng; Feng Shiping

2006-01-01

Within the t-J ladder model, superconductivity with a modified d-wave symmetry in doped two-leg ladder cuprates is investigated based on the kinetic energy driven superconducting mechanism. It is shown that the spin-liquid ground-state at the half-filling evolves into the superconducting ground-state upon doping. In analogy to the doping dependence of the superconducting transition temperature in the planar cuprate superconductors, the superconducting transition temperature in doped two-leg ladder cuprates increases with increasing doping in the underdoped regime, and reaches a maximum in the optimal doping, then decreases in the overdoped regime

Controllable manipulation of superconductivity using magnetic vortices

International Nuclear Information System (INIS)

Villegas, J E; Schuller, Ivan K

2011-01-01

The magneto-transport of a superconducting/ferromagnetic hybrid structure, consisting of a superconducting thin film in contact with an array of magnetic nanodots in the so-called 'magnetic vortex state', exhibits interesting properties. For certain magnetic states, the stray magnetic field from the vortex array is intense enough to drive the superconducting film into the normal state. In this fashion, the normal-to-superconducting phase transition can be controlled by the magnetic history. The strong coupling between superconducting and magnetic subsystems allows characteristically ferromagnetic properties, such as hysteresis and remanence, to be dramatically transferred into the transport properties of the superconductor.

Superconducting pipes and levitating magnets.

Science.gov (United States)

Levin, Yan; Rizzato, Felipe B

2006-12-01

Motivated by a beautiful demonstration of the Faraday and the Lenz laws in which a small neodymium magnet falls slowly through a conducting nonferromagnetic tube, we consider the dynamics of a magnet falling coaxially through a superconducting pipe. Unlike the case of normal conducting pipes, in which the magnet quickly reaches the terminal velocity, inside a superconducting tube the magnet falls freely. On the other hand, to enter the pipe the magnet must overcome a large electromagnetic energy barrier. For sufficiently strong magnets, the barrier is so large that the magnet will not be able to penetrate it and will be levitated over the mouth of the pipe. We calculate the work that must done to force the magnet to enter a superconducting tube. The calculations show that superconducting pipes are very efficient at screening magnetic fields. For example, the magnetic field of a dipole at the center of a short pipe of radius a and length L approximately > a decays, in the axial direction, with a characteristic length xi approximately 0.26a. The efficient screening of the magnetic field might be useful for shielding highly sensitive superconducting quantum interference devices. Finally, the motion of the magnet through a superconducting pipe is compared and contrasted to the flow of ions through a trans-membrane channel.

Superconducting Metallic Glass Transition-Edge-Sensors

Science.gov (United States)

Hays, Charles C. (Inventor)

2013-01-01

A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

Cooldown of superconducting magnet strings

International Nuclear Information System (INIS)

Yuecel, A.; Carcagno, R.H.

1995-01-01

A numerical model for the cooldown of the superconducting magnet strings in the Accelerator System String Test (ASST) Facility at the Superconducting Super Collider (SSC) Laboratory is presented. Numerical results are compared with experimental data from the ASST test runs. Agreement between the numerical predictions and experiments is very good over the entire range from room temperature to liquid helium temperatures. The model can be readily adapted to predict the cooldown and warmup behavior of other superconducting magnets or cold masses

Superconductivity in bad metals

International Nuclear Information System (INIS)

Emery, V.J.; Kivelson, S.A.

1995-01-01

It is argued that many synthetic metals, including high temperature superconductors are ''bad metals'' with such a poor conductivity that the usual mean-field theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. Some consequences for high temperature superconductors are described

Mechanical Design of Superconducting Accelerator Magnets

International Nuclear Information System (INIS)

Toral, F

2014-01-01

This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques

Mechanical Design of Superconducting Accelerator Magnets

CERN Document Server

Toral, Fernando

2014-07-17

This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques.

Mechanical Design of Superconducting Accelerator Magnets

Energy Technology Data Exchange (ETDEWEB)

Toral, F [Madrid, CIEMAT (Spain)

2014-07-01

This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques.

Can magnetism and superconductivity coexist

International Nuclear Information System (INIS)

Ishikawa, M.

1982-01-01

Recent syntheses of rare earth (RE) ternary superconductors such as (RE)Mo 6 X 8 (X=S or Se) and (RE)Rh 4 B 4 have provided the first opportunity to explore the interaction between magnetism and superconductivity in detail owing to their particular crystal structure. The regular sublattice of the rare-earth ions in these new ternary compounds undergoes a ferro- or antiferromagnetic phase transition in the superconducting state. If the transition is antiferromagnetic, the superconductivity is preserved so that true coexistence results. If it is ferromagnetic, on the other hand, the superconductivity eventually gives way to uniform ferromagnetism at low temperatures. However, recent theories predict several possible states of coexistence even in ferromagnetic superconductors. This article reviews aspects of these new phase transitions in ternary superconductors. (author)

New world of Gossamer superconductivity

International Nuclear Information System (INIS)

Maki, Kazumi; Haas, Stephan; Parker, David; Won, Hyekyung; Dora, Balazs; Virosztek, Attila

2006-01-01

Since the discovery of the high-T c cuprate superconductor La 2-x BaCuO 4 in 1986 by Bednorz and Mueller, controversy regarding the nature or origin of this remarkable superconductivity has continued. However, d-wave superconductivity in the hole-doped cuprates, arising due to the anti-paramagnon exchange, was established around 1994. More recently we have shown that the mean field theory, like the BCS theory of superconductivity and Landau's Fermi liquid theory are adequate to describe the cuprates. The keys for this development are the facts that a) the pseudogap phase is d-wave density wave (dDW) and that the high-T c cuprate superconductivity is gossamer (i.e. it exists in the presence of dDW). (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Superconducting generator technology--an overview

International Nuclear Information System (INIS)

Edmonda, J.S.

1979-01-01

Application of superconducting technology to field windings of large ac generators provides virtually unlimited field capability without incurring resistive losses in the winding. Several small-scale superconducting generators have been built and tested demonstrating the feasibility of such concepts. For machines of much larger capacity, conceptual designs for 300 Mva and 1200 Mva have been completed. The development of a 300 Mva generator is projected. Designed, engineered and fabricated as a turbo generator, the superconducting machine is to be installed in a power plant, tested and operated in concert with a prime mover, the steam generator and the auxiliary support systems of the power plant. This will provide answers to the viability of operating a superconducting machine and its cryogenic handling systems in a full time, demanding environment. 21 refs

Medium scale test study of chemical cleaning technique for secondary side of SG in PWR

International Nuclear Information System (INIS)

Zhang Mengqin; Zhang Shufeng; Yu Jinghua; Hou Shufeng

1997-08-01

The medium scale test study of chemical cleaning technique for removing corrosion product (Fe 3 O 4 ) in secondary side of SG in PWR has been completed. The test has been carried out in a medium scale test loop. The medium scale test evaluated the effect of the chemical cleaning technique (temperature, flow rate, cleaning time, cleaning process), the state of corrosion product deposition on magnetite (Fe 3 O 4 ) solubility and safety of materials of SG in cleaning process. The inhibitor component of chemical cleaning agent has been improved by electrochemical linear polarization method, the effect of inhibitor on corrosion resistance of materials have been examined in the medium scale test loop, the most components of chemical cleaning agent have been obtained, the EDTA is main component in cleaning agent. The electrochemical method for monitor corrosion of materials during cleaning process has been completed in the laboratory. The study of the medium scale test of chemical cleaning technique have had the optimum chemical cleaning technique for remove corrosion product in SG secondary side of PWR. (9 refs., 4 figs., 11 tabs.)

Heavy-ion superconducting linacs

International Nuclear Information System (INIS)

Delayen, J.R.

1989-01-01

This paper reviews the status of the superconducting heavy-ion accelerators. Most of them are linacs used as boosters for tandem electrostatic accelerators, although the technology is being extended to very low velocity to eliminate the need for an injector. The characteristics and features of the various superconducting heavy-ion accelerators are discussed. 45 refs

Heavy-ion superconducting linacs

Energy Technology Data Exchange (ETDEWEB)

Delayen, J.R.

1989-01-01

This paper reviews the status of the superconducting heavy-ion accelerators. Most of them are linacs used as boosters for tandem electrostatic accelerators, although the technology is being extended to very low velocity to eliminate the need for an injector. The characteristics and features of the various superconducting heavy-ion accelerators are discussed. 45 refs.

RADIOFREQUENCY SUPERCONDUCTIVITY: Workshop

International Nuclear Information System (INIS)

Lengeler, Herbert

1989-01-01

Superconducting radiofrequency is already playing an important role in the beam acceleration system for the TRISTAN electron-positron collider at the Japanese KEK Laboratory and new such systems are being prepared for other major machines. Thus the fourth Workshop on Radiofrequency Superconductivity, organized by KEK under the chairmanship of local specialist Yuzo Kojima and held just before the International Conference on High Energy Accelerators, had much progress to review and even more to look forward to

Connectivity and superconductivity

CERN Document Server

Rubinstein, Jacob

2000-01-01

The motto of connectivity and superconductivity is that the solutions of the Ginzburg--Landau equations are qualitatively influenced by the topology of the boundaries, as in multiply-connected samples. Special attention is paid to the "zero set", the set of the positions (also known as "quantum vortices") where the order parameter vanishes. The effects considered here usually become important in the regime where the coherence length is of the order of the dimensions of the sample. It takes the intuition of physicists and the awareness of mathematicians to find these new effects. In connectivity and superconductivity, theoretical and experimental physicists are brought together with pure and applied mathematicians to review these surprising results. This volume is intended to serve as a reference book for graduate students and researchers in physics or mathematics interested in superconductivity, or in the Schrödinger equation as a limiting case of the Ginzburg--Landau equations.

Large Superconducting Magnet Systems

CERN Document Server

Védrine, P.

2014-07-17

The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb$_{3}$Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

Superconducting accelerator magnet design

International Nuclear Information System (INIS)

Wolff, S.

1994-01-01

Superconducting dipoles, quadrupoles and correction magnets are necessary to achieve the high magnetic fields required for big accelerators presently in construction or in the design phase. Different designs of superconducting accelerator magnets are described and the designs chosen at the big accelerator laboratories are presented. The most frequently used cosθ coil configuration is discussed in detail. Approaches for calculating the magnetic field quality including coil end fields are presented. Design details of the cables, coils, mechanical structures, yokes, helium vessels and cryostats including thermal radiation shields and support structures used in superconducting magnets are given. Necessary material properties are mentioned. Finally, the main results of magnetic field measurements and quench statistics are presented. (orig.)

Large Superconducting Magnet Systems

Energy Technology Data Exchange (ETDEWEB)

Védrine, P [Saclay (France)

2014-07-01

The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb3Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

Acoustic wave spread in superconducting-normal-superconducting sandwich

International Nuclear Information System (INIS)

Urushadze, G.I.

2004-01-01

The acoustic wave spread, perpendicular to the boundaries between superconducting and normal metals in superconducting-normal-superconducting (SNS) sandwich has been considered. The alternate current flow sound induced by the Green function method has been found and the coefficient of the acoustic wave transmission through the junction γ=(S 1 -S 2 )/S 1 , (where S 1 and S 2 are average energy flows formed on the first and second boundaries) as a function of the phase difference between superconductors has been investigated. It is shown that while the SNS sandwich is almost transparent for acoustic waves (γ 0 /τ), n=0,1,2, ... (where τ 0 /τ is the ratio of the broadening of the quasiparticle energy levels in impurity normal metal as a result of scattering of the carriers by impurities 1/τ to the spacing between energy levels 1/τ 0 ), γ=2, (S 2 =-S 1 ), which corresponds to the full reflection of the acoustic wave from SNS sandwich. This result is valid for the limit of a pure normal metal but in the main impurity case there are two amplification and reflection regions for acoustic waves. The result obtained shows promise for the SNS sandwich as an ideal mirror for acoustic wave reflection

Valence skipping driven superconductivity and charge Kondo effect

International Nuclear Information System (INIS)

Yanagisawa, Takashi; Hase, Izumi

2013-01-01

Highlights: •Valence skipping in metallic compounds can give rise to an unconventional superconductivity. •Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. •The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. •We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. •There is a high temperature region near the boundary. -- Abstract: Valence skipping in metallic compounds can give rise to an unconventional superconductivity. Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. The superconducting state is changed into a metallic state with a local singlet as the attractive interaction |U| increases. There is a high temperature region near the boundary

Superconducting magnet

Science.gov (United States)

1985-01-01

Extensive computer based engineering design effort resulted in optimization of a superconducting magnet design with an average bulk current density of approximately 12KA/cm(2). Twisted, stranded 0.0045 inch diameter NbTi superconductor in a copper matrix was selected. Winding the coil from this bundle facilitated uniform winding of the small diameter wire. Test coils were wound using a first lot of the wire. The actual packing density was measured from these. Interwinding voltage break down tests on the test coils indicated the need for adjustment of the wire insulation on the lot of wire subsequently ordered for construction of the delivered superconducting magnet. Using the actual packing densities from the test coils, a final magnet design, with the required enhancement and field profile, was generated. All mechanical and thermal design parameters were then also fixed. The superconducting magnet was then fabricated and tested. The first test was made with the magnet immersed in liquid helium at 4.2K. The second test was conducted at 2K in vacuum. In the latter test, the magnet was conduction cooled from the mounting flange end.

Half-metallic superconducting triplet spin multivalves

Science.gov (United States)

Alidoust, Mohammad; Halterman, Klaus

2018-02-01

We study spin switching effects in finite-size superconducting multivalve structures. We examine F1F2SF3 and F1F2SF3F4 hybrids where a singlet superconductor (S) layer is sandwiched among ferromagnet (F) layers with differing thicknesses and magnetization orientations. Our results reveal a considerable number of experimentally viable spin-valve configurations that lead to on-off switching of the superconducting state. For S widths on the order of the superconducting coherence length ξ0, noncollinear magnetization orientations in adjacent F layers with multiple spin axes leads to a rich variety of triplet spin-valve effects. Motivated by recent experiments, we focus on samples where the magnetizations in the F1 and F4 layers exist in a fully spin-polarized half-metallic phase, and calculate the superconducting transition temperature, spatially and energy resolved density of states, and the spin-singlet and spin-triplet superconducting correlations. Our findings demonstrate that superconductivity in these devices can be completely switched on or off over a wide range of magnetization misalignment angles due to the generation of equal-spin and opposite-spin triplet pairings.

Fullerides - Superconductivity at the limit

NARCIS (Netherlands)

Palstra, Thomas T. M.

The successful synthesis of highly crystalline Cs3C60, exhibiting superconductivity up to a record temperature for fullerides of 38 K, demonstrates a powerful synthetic route for investigating the origin of superconductivity in this class of materials.

Fast superconducting magnetic field switch

Science.gov (United States)

Goren, Yehuda; Mahale, Narayan K.

1996-01-01

The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

Fast superconducting magnetic field switch

International Nuclear Information System (INIS)

Goren, Y.; Mahale, N.K.

1996-01-01

The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs

Superconductivity in compensated and uncompensated semiconductors

Directory of Open Access Journals (Sweden)

Youichi Yanase and Naoyuki Yorozu

2008-01-01

Full Text Available We investigate the localization and superconductivity in heavily doped semiconductors. The crossover from the superconductivity in the host band to that in the impurity band is described on the basis of the disordered three-dimensional attractive Hubbard model for binary alloys. The microscopic inhomogeneity and the thermal superconducting fluctuation are taken into account using the self-consistent 1-loop order theory. The superconductor-insulator transition accompanies the crossover from the host band to the impurity band. We point out an enhancement of the critical temperature Tc around the crossover. Further localization of electron wave functions leads to the localization of Cooper pairs and induces the pseudogap. We find that both the doping compensation by additional donors and the carrier increase by additional acceptors suppress the superconductivity. A theoretical interpretation is proposed for the superconductivity in the boron-doped diamond, SiC, and Si.

New world of Gossamer superconductivity

Energy Technology Data Exchange (ETDEWEB)

Maki, Kazumi; Haas, Stephan; Parker, David [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Won, Hyekyung [Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Str. 38, 01187, Dresden (Germany); Department of Physics, Hallym University, Chuncheon 200-702 (Korea); Dora, Balazs; Virosztek, Attila [Department of Physics, Budapest University of Technology and Economics, 1521 Budapest (Hungary)

2006-09-15

Since the discovery of the high-T {sub c} cuprate superconductor La{sub 2-x}BaCuO{sub 4} in 1986 by Bednorz and Mueller, controversy regarding the nature or origin of this remarkable superconductivity has continued. However, d-wave superconductivity in the hole-doped cuprates, arising due to the anti-paramagnon exchange, was established around 1994. More recently we have shown that the mean field theory, like the BCS theory of superconductivity and Landau's Fermi liquid theory are adequate to describe the cuprates. The keys for this development are the facts that a) the pseudogap phase is d-wave density wave (dDW) and that the high-T{sub c} cuprate superconductivity is gossamer (i.e. it exists in the presence of dDW). (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Earlier and recent aspects of superconductivity

International Nuclear Information System (INIS)

Bednorz, J.G.; Muller, K.A.

1990-01-01

Contemporary knowledge of superconductivity is set against its historical background in this book. First, the highlights of superconductivity research in the twentieth century are reviewed. Further contributions then describe the basic phenomena resulting from the macroscopic quantum state of superconductivity (such as zero resistivity, the Meissner-Ochsenfeld effect, and flux quantization) and review possible mechanisms, including the classical BCS theory and the more recent alternative theories. The main categories of superconductors - elements, intermetallic phases, chalcogenides, oxides and organic compounds - are described. Common features and differences in their structure and electronic properties are pointed out. This overview of superconductivity is completed by a discussion of properties related to the coherence length

Superconducting devices at Brookhaven National Laboratory

International Nuclear Information System (INIS)

Dahl, P.F.

1978-04-01

The various ongoing programs in applied superconductivity supported by BNL are summarized, including the development of high field ac and dc superconducting magnets for accelerators and other applications, of microwave deflecting cavities for high energy particle beam separators, and of cables for underground power transmission, and materials research on methods of fabricating new superconductors and on metallurgical properties affecting the performance of superconducting devices

Superconductivity and macroscopic quantum phenomena

International Nuclear Information System (INIS)

Rogovin, D.; Scully, M.

1976-01-01

It is often asserted that superconducting systems are manifestations of quantum mechanics on a macroscopic scale. In this review article it is demonstrated that this quantum assertion is true within the framework of the microscopic theory of superconductivity. (Auth.)

Superconductivity in heavily boron-doped silicon carbide

Directory of Open Access Journals (Sweden)

Markus Kriener, Takahiro Muranaka, Junya Kato, Zhi-An Ren, Jun Akimitsu and Yoshiteru Maeno

2008-01-01

Full Text Available The discoveries of superconductivity in heavily boron-doped diamond in 2004 and silicon in 2006 have renewed the interest in the superconducting state of semiconductors. Charge-carrier doping of wide-gap semiconductors leads to a metallic phase from which upon further doping superconductivity can emerge. Recently, we discovered superconductivity in a closely related system: heavily boron-doped silicon carbide. The sample used for that study consisted of cubic and hexagonal SiC phase fractions and hence this led to the question which of them participated in the superconductivity. Here we studied a hexagonal SiC sample, free from cubic SiC phase by means of x-ray diffraction, resistivity, and ac susceptibility.

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

Directory of Open Access Journals (Sweden)

Guillaume Moreira

2013-08-01

Full Text Available The range of applications of cellulose, a glucose-based polysaccharide, is limited by its inherently poor mechanical properties. The grafting of synthetic polymer chains by, for example, a “grafting from” process may provide the means to broaden the range of applications. The nitroxide-mediated polymerization (NMP method is a technique of choice to control the length, the composition and the architecture of the grafted copolymers. Nevertheless, cellulose is difficult to solubilize in organic media because of inter- and intramolecular hydrogen bonds. One possibility to circumvent this limitation is to solubilize cellulose in N,N-dimethylformamide (DMF or N,N-dimethylacetamide (DMA with 5 to 10 wt % of lithium salts (LiCl or LiBr, and carry out grafted polymerization in this medium. The stability of nitroxides such as SG1 has not been studied under these conditions yet, even though these parameters are of crucial importance to perform the graft modification of polysaccharide by NMP. The aim of this work is to offer a model study of the stability of the SG1 nitroxide in organic media in the presence of unprotected glucose or cellobiose (used as a model of cellulose and in the presence of lithium salts (LiBr or LiCl in DMF or DMA.Contrary to TEMPO, SG1 proved to be stable in the presence of unprotected sugar, even with an excess of 100 molar equivalents of glucose. On the other hand, lithium salts in DMF or DMA clearly degrade SG1 nitroxide as proven by electron-spin resonance measurements. The instability of SG1 in these lithium-containing solvents may be explained by the acidification of the medium by the hydrolysis of DMA in the presence of LiCl. This, in turn, enables the disproportionation of the SG1 nitroxide into an unstable hydroxylamine and an oxoammonium ion.Once the conditions to perform an SG1-based nitroxide-mediated graft polymerization from cellobiose have been established, the next stage of this work will be the modification of

CRISPR/Cas9-mediated gene knockout is insensitive to target copy number but is dependent on guide RNA potency and Cas9/sgRNA threshold expression level.

Science.gov (United States)

Yuen, Garmen; Khan, Fehad J; Gao, Shaojian; Stommel, Jayne M; Batchelor, Eric; Wu, Xiaolin; Luo, Ji

2017-11-16

CRISPR/Cas9 is a powerful gene editing tool for gene knockout studies and functional genomic screens. Successful implementation of CRISPR often requires Cas9 to elicit efficient target knockout in a population of cells. In this study, we investigated the role of several key factors, including variation in target copy number, inherent potency of sgRNA guides, and expression level of Cas9 and sgRNA, in determining CRISPR knockout efficiency. Using isogenic, clonal cell lines with variable copy numbers of an EGFP transgene, we discovered that CRISPR knockout is relatively insensitive to target copy number, but is highly dependent on the potency of the sgRNA guide sequence. Kinetic analysis revealed that most target mutation occurs between 5 and 10 days following Cas9/sgRNA transduction, while sgRNAs with different potencies differ by their knockout time course and by their terminal-phase knockout efficiency. We showed that prolonged, low level expression of Cas9 and sgRNA often fails to elicit target mutation, particularly if the potency of the sgRNA is also low. Our findings provide new insights into the behavior of CRISPR/Cas9 in mammalian cells that could be used for future improvement of this platform. Published by Oxford University Press on behalf of Nucleic Acids Research 2017.

A study on metastable superconducting magnets

International Nuclear Information System (INIS)

Koyama, Kenichi

1976-01-01

It is important to construct superconducting magnets as cheap as possible. One of the methods to achieve such a purpose is to save the superconducting material and operate the magnets at a high current density. Therefore it is useful to investigate the requirements for the operation of metastable superconducting magnets which can work at a current higher than the recovery current. Using the theory of flux jump, we introduce a ''stable current'' below which no flux jump can occur. On a rough approximation, it is given by I sub(s) =√A P sub(i) H sub(e) T sub(o) f(x)/rho where A : cross-section of the composite conductor. P sub(i) : total perimeter of all the superconducting cores. h sub(e) : effective heat transfer coefficient to the liquid helium through the stabilizer. T sub(o) : a characteristic temperature of the superconducting cores. f(x) : a characteristic function for the relative core radius x. rho : effective resistivity of the composite. Then it is shown that superconducting magnets can operate without unexpected normal transitions in the region enclosed by the two curves of I sub(s) and I sub(c). Next, we discuss the characteristics of our saddle shaped superconducting magnet for an one-KW MHD generator. We found that, 1) the magnet does safely operate in the metastable state; 2) the characteristics of the magnet are consistent with our theoretical results. (auth.)

Thermal expansion of coexistence of ferromagnetism and superconductivity

International Nuclear Information System (INIS)

Hatayama, Nobukuni; Konno, Rikio

2010-01-01

The temperature dependence of thermal expansion of coexistence of ferromag-netism and superconductivity below the superconducting transition temperature T cu of a majority spin conduction band is investigated. Majority spin and minority spin superconducting gaps exist in the coexistent state. We assume that the Curie temperature is much larger than the superconducting transition temperatures. The free energy that Linder et al. [Phys. Rev. B76, 054511 (2007)] derived is used. The thermal expansion of coexistence of ferromagnetism and superconductivity is derived by the application of the method of Takahashi and Nakano [J. Phys.: Condens. Matter 18, 521 (2006)]. We find that we have the anomalies of the thermal expansion in the vicinity of the superconducting transition temperatures.

Superconductivity in multilayer perovskite. Weak coupling analysis

International Nuclear Information System (INIS)

Koikegami, Shigeru; Yanagisawa, Takashi

2006-01-01

We investigate the superconductivity of a three-dimensional d-p model with a multilayer perovskite structure on the basis of the second-order perturbation theory within the weak coupling framework. Our model has been designed with multilayer high-T c superconducting cuprates in mind. In our model, multiple Fermi surfaces appear, and the component of a superconducting gap function develops on each band. We have found that the multilayer structure can stabilize the superconductivity in a wide doping range. (author)

Crystalline color superconductivity

International Nuclear Information System (INIS)

Alford, Mark; Bowers, Jeffrey A.; Rajagopal, Krishna

2001-01-01

In any context in which color superconductivity arises in nature, it is likely to involve pairing between species of quarks with differing chemical potentials. For suitable values of the differences between chemical potentials, Cooper pairs with nonzero total momentum are favored, as was first realized by Larkin, Ovchinnikov, Fulde, and Ferrell (LOFF). Condensates of this sort spontaneously break translational and rotational invariance, leading to gaps which vary periodically in a crystalline pattern. Unlike the original LOFF state, these crystalline quark matter condensates include both spin-zero and spin-one Cooper pairs. We explore the range of parameters for which crystalline color superconductivity arises in the QCD phase diagram. If in some shell within the quark matter core of a neutron star (or within a strange quark star) the quark number densities are such that crystalline color superconductivity arises, rotational vortices may be pinned in this shell, making it a locus for glitch phenomena

Civilian applications for superconducting magnet technology developed for defense

International Nuclear Information System (INIS)

Johnson, R.A.; Klein, S.W.; Gurol, H.

1986-01-01

Seventy years after its discovery, superconducting technology is beginning to play an important role in the civilian sector. Strategic defense initiative (SDI)-related research in space- and ground-based strategic defense weapons, particularly research efforts utilizing superconducting magnet energy storage, magnetohydrodynamics (MHD), and superconducting pulsed-power devices, have direct applications in the civilian sector as well and are discussed in the paper. Other applications of superconducting magnets, which will be indirectly enhanced by the overall advancement in superconducting technology, include high-energy physics accelerators, magnetic resonance imaging, materials purifying, water purifying, superconducting generators, electric power transmission, magnetically levitated trains, magnetic-fusion power plants, and superconducting computers

Ac loss measurements on a superconducting transformer for a 25 kA superconducting rectifier

NARCIS (Netherlands)

ten Kate, Herman H.J.; Mulders, J.M.; de Reuver, J.L.; van de Klundert, L.J.M.

1984-01-01

Ac loss measurements have been performed on a superconducting transformer. The transformer is a part of a 25 kA thermally switched superconducting rectifier operating at a frequency of 0.1 Hz. The loss measurements have been automatized by means of a microcomputer sampling four relevant signals and

Superconducting three element synchronous ac machine

International Nuclear Information System (INIS)

Boyer, L.; Chabrerie, J.P.; Mailfert, A.; Renard, M.

1975-01-01

There is a growing interest in ac superconducting machines. Of several new concepts proposed for these machines in the last years one of the most promising seems to be the ''three elements'' concept which allows the cancellation of the torque acting on the superconducting field winding, thus overcoming some of the major contraints. This concept leads to a device of induction-type generator. A synchronous, three element superconducting ac machine is described, in which a room temperature, dc fed rotating winding is inserted between the superconducting field winding and the ac armature. The steady-state machine theory is developed, the flux linkages are established, and the torque expressions are derived. The condition for zero torque on the field winding, as well as the resulting electrical equations of the machine, are given. The theoretical behavior of the machine is studied, using phasor diagrams and assuming for the superconducting field winding either a constant current or a constant flux condition

Controlling superconductivity by tunable quantum critical points.

Science.gov (United States)

Seo, S; Park, E; Bauer, E D; Ronning, F; Kim, J N; Shim, J-H; Thompson, J D; Park, Tuson

2015-03-04

The heavy fermion compound CeRhIn5 is a rare example where a quantum critical point, hidden by a dome of superconductivity, has been explicitly revealed and found to have a local nature. The lack of additional examples of local types of quantum critical points associated with superconductivity, however, has made it difficult to unravel the role of quantum fluctuations in forming Cooper pairs. Here, we show the precise control of superconductivity by tunable quantum critical points in CeRhIn5. Slight tin-substitution for indium in CeRhIn5 shifts its antiferromagnetic quantum critical point from 2.3 GPa to 1.3 GPa and induces a residual impurity scattering 300 times larger than that of pure CeRhIn5, which should be sufficient to preclude superconductivity. Nevertheless, superconductivity occurs at the quantum critical point of the tin-doped metal. These results underline that fluctuations from the antiferromagnetic quantum criticality promote unconventional superconductivity in CeRhIn5.

Superconducting quantum circuits theory and application

OpenAIRE

Deng, Xiuhao

2015-01-01

Superconducting quantum circuit models are widely used to understand superconducting devices. This thesis consists of four studies wherein the superconducting quantum circuit is used to illustrate challenges related to quantum information encoding and processing, quantum simulation, quantum signal detection and amplification.The existence of scalar Aharanov-Bohm phase has been a controversial topic for decades. Scalar AB phase, defined as time integral of electric potential, gives rises to a...

Superconducting Qubit Optical Transducer (SQOT)

Science.gov (United States)

2015-08-05

parts on optical signals and any quasiparticle loss caused by optical photons on microwave signals. Using a superconducting 3D cavity as the microwave...plasmonic and quasiparticle losses. 3. The electro-optic material should be easily integrable with superconducting circuits. A fully integrated

Superconducting bearings for flywheel applications

DEFF Research Database (Denmark)

Abrahamsen, A.B.

2001-01-01

A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

Superconductivity, energy storage and switching

International Nuclear Information System (INIS)

Laquer, H.L.

1974-01-01

The phenomenon of superconductivity can contribute to the technology of energy storage and switching in two distinct ways. On one hand the zero resistivity of the superconductor can produce essentially infinite time constants so that an inductive storage system can be charged from very low power sources. On the other hand, the recovery of finite resistivity in a normal-going superconducting switch can take place in extremely short times, so that a system can be made to deliver energy at a very high power level. Topics reviewed include: physics of superconductivity, limits to switching speed of superconductors, physical and engineering properties of superconducting materials and assemblies, switching methods, load impedance considerations, refrigeration economics, limitations imposed by present day and near term technology, performance of existing and planned energy storage systems, and a comparison with some alternative methods of storing and switching energy. (U.S.)

Superconductivity in all its states

CERN Multimedia

Globe Info

2011-01-01

Temporary exhibition at the Saint-Genis-Pouilly Tourist Office. For the 100th anniversary of its discovery, take a plunge into the amazing world of superconductivity. Some materials, when cooled down to extreme temperatures, acquire a remarkable property -  they become superconducting. Superconductivity is a rare example of a quantum effect that can be witnessed on the macroscopic scale and is today at the heart of much research. In laboratories, researchers try to gain a better understanding of its origins, study new superconducting materials, explore the phenomenon at the nanometric scale and pursue their indefatigable search for new applications. Monday to Friday: 09:00 a.m. to 12:00 and 2:30 p.m. to 6:30 p.m. Saturday: 10:00 a.m. to 12:00 noon » Open to all – Admission free For further information: +33 (0)4 50 42 29 37

ASC 84: applied superconductivity conference. Final program and abstracts

International Nuclear Information System (INIS)

1984-01-01

Abstracts are given of presentations covering: superconducting device fabrication; applications of rf superconductivity; conductor stability and losses; detectors and signal processing; fusion magnets; A15 and Nb-Ti conductors; stability, losses, and various conductors; SQUID applications; new applications of superconductivity; advanced conductor materials; high energy physics applications of superconductivity; electronic materials and characterization; general superconducting electronics; ac machinery and new applications; digital devices; fusion and other large scale applications; in-situ and powder process conductors; ac applications; synthesis, properties, and characterization of conductors; superconducting microelectronics

ASC 84: applied superconductivity conference. Final program and abstracts

Energy Technology Data Exchange (ETDEWEB)

1984-01-01

Abstracts are given of presentations covering: superconducting device fabrication; applications of rf superconductivity; conductor stability and losses; detectors and signal processing; fusion magnets; A15 and Nb-Ti conductors; stability, losses, and various conductors; SQUID applications; new applications of superconductivity; advanced conductor materials; high energy physics applications of superconductivity; electronic materials and characterization; general superconducting electronics; ac machinery and new applications; digital devices; fusion and other large scale applications; in-situ and powder process conductors; ac applications; synthesis, properties, and characterization of conductors; superconducting microelectronics. (LEW)

Color-symmetric superconductivity in a phenomenological QCD model

DEFF Research Database (Denmark)

Bohr, Henrik; Providencia, C.; Providencia, J. da

2009-01-01

In this paper, we construct a theory of the NJL type where superconductivity is present, and yet the superconducting state remains, in the average, color symmetric. This shows that the present approach to color superconductivity is consistent with color singletness. Indeed, quarks are free...... in the deconfined phase, but the deconfined phase itself is believed to be a color singlet. The usual description of the color superconducting state violates color singletness. On the other hand, the color superconducting state here proposed is color symmetric in the sense that an arbitrary color rotation leads...

Application of superconductivity to pulse fields

International Nuclear Information System (INIS)

Saito, Shigeo; Suzawa, Chizuru; Ohkura, Kengo; Nagata, Masayuki; Kawashima, Masao

1984-01-01

Numerous attempts to apply the superconductive phenomena of zero electrical resistivity to AC (pulsed) magnets in addition to conventional DC magnet fields are being made in the areas of poloidal coils of nuclear fusion, energy storage, rotary machines, and induction for stabilization of electric power systems. In pulsed superconductive magnets, the stability of the superconductivity and the generation of heat due to AC loss are serious problems. Based on the knowledge obtained through the development of various types of superconductors, magnets, cryostats, and other superconductive-related products, Cu-Ni/Cu/Nb-Ti mixed-matrix fine multifilamentary superconductor wire and the stable, low AC loss superconductors used therein, magnets, and FRP cryostats are developed and manufactured. (author)

Teledyne's historical contribution to developing superconductivity

International Nuclear Information System (INIS)

McDonald, W.K.

1986-01-01

Of the contributions made to superconductivity by Teledyne Wah Change Albany (TWCA), two have been outstanding. The first is the establishment of a stable and low cost NbTi alloy. Estimates of cost savings passed along to conductor manufacturers and, subsequently, to the applications of superconductivity range between $24,000,000 and $31,000,000 over the years from 1980 to present. Secondly, TWCA has understood the necessity of cooperating with the scientific community in order to understand critical relationships of metallurgy to superconductivity characteristics. The knowledge gained is integrated into alloy production on a commercial basis. The most notable example is the recent increase in current density prospects for the proposed Superconducting Super Collider

Application of superconductivity in cyclotron construction

International Nuclear Information System (INIS)

Blosser, H.G.

1982-01-01

This paper reviews major concepts and design features of the new class of cyclotrons which use superconducting coils to provide main magnet excitation. The discussion begins with a brief historical review tracing the evolution of these ''superconducting'' cyclotrons and the impact of this application of superconductivity in pushing back traditional cyclotron construction limits. This is followed by a review of the principal phenomena which come into play to set new limits on the operating regime, and the nature of these limits, some of which arise from orbit properties and some of which result from construction intricacies in the coil and in the rf system. Conclusions anticipate a future widely encompassing role in the application of superconductivity to cyclotron

Superconducting magnetic quadrupole

Energy Technology Data Exchange (ETDEWEB)

Kim, J.W.; Shepard, K.W.; Nolen, J.A.

1995-08-01

A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

Science.gov (United States)

Norem, James H.; Pellin, Michael J.

2013-06-11

Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

High temperature interface superconductivity

International Nuclear Information System (INIS)

Gozar, A.; Bozovic, I.

2016-01-01

Highlight: • This review article covers the topic of high temperature interface superconductivity. • New materials and techniques used for achieving interface superconductivity are discussed. • We emphasize the role played by the differences in structure and electronic properties at the interface with respect to the bulk of the constituents. - Abstract: High-T_c superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-T_c Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

Superconducting magnets for HERA

International Nuclear Information System (INIS)

Wolff, S.

1987-01-01

The Hadron-Electron-Ring Accelerator (HERA) presently under construction at DESY, Hamburg, consists of an electron storage ring of 30 GeV and a proton storage ring of 820 GeV. Superconducting magnets are used for the proton ring. There are 416 superconducting bending magnets of 4.698 T central field and 8.824 m magnetic length, 224 superconducting quadrupoles of 91.2 T/m central gradient and many superconducting correction dipoles, quadrupoles and sextupoles. The main dipoles and quadrupoles consist of two-layer coils of 75 mm inner diameter clammed with aluminium (for the dipoles) or stainless steel laminations (for the quadrupoles). The collared coils are surrounded by a laminated cold iron yoke and supported inside a low loss cryostat. The protection system uses cold diodes to bypass the current around a quenching magnet. The magnets are cooled with one phase helium supplied by a 3 block central refrigeration system of 20 kW refrigeration power at 4.3 K. Two helium is returned through the magnets in good thermal contact with the one phase helium in the dipoles for temperature control. This paper describes the magnet system and gives the results obtained for prototype magnets

Applied superconductivity. Handbook on devices and applications. Vol. 1 and 2

Energy Technology Data Exchange (ETDEWEB)

Seidel, Paul (ed.) [Jena Univ. (Germany). Inst. fuer Festkoerperphysik, AG Tieftemperaturphysik

2015-07-01

The both volumes contain the following 12 chapters: 1. Fundamentals; 2. Superconducting Materials; 3. Technology, Preparation, and Characterization (bulk materials, thin films, multilayers, wires, tapes; cooling); 4, Superconducting Magnets; 5. Power Applications (superconducting cables, superconducting current leads, fault current limiters, transformers, SMES and flywheels; rotating machines; SmartGrids); 6. Superconductive Passive Devices (superconducting microwave components; cavities for accelerators; superconducting pickup coils; magnetic shields); 7. Applications in Quantum Metrology (superconducting hot electron bolometers; transition edge sensors; SIS Mixers; superconducting photon detectors; applications at Terahertz frequency; detector readout); 8. Superconducting Radiation and Particle Detectors; 9. Superconducting Quantum Interference (SQUIDs); 10. Superconductor Digital Electronics; 11. Other Applications (Josephson arrays as radiation sources. Tunable microwave devices) and 12. Summary and Outlook (of the superconducting devices).

Applied superconductivity. Handbook on devices and applications. Vol. 1 and 2

International Nuclear Information System (INIS)

Seidel, Paul

2015-01-01

The both volumes contain the following 12 chapters: 1. Fundamentals; 2. Superconducting Materials; 3. Technology, Preparation, and Characterization (bulk materials, thin films, multilayers, wires, tapes; cooling); 4, Superconducting Magnets; 5. Power Applications (superconducting cables, superconducting current leads, fault current limiters, transformers, SMES and flywheels; rotating machines; SmartGrids); 6. Superconductive Passive Devices (superconducting microwave components; cavities for accelerators; superconducting pickup coils; magnetic shields); 7. Applications in Quantum Metrology (superconducting hot electron bolometers; transition edge sensors; SIS Mixers; superconducting photon detectors; applications at Terahertz frequency; detector readout); 8. Superconducting Radiation and Particle Detectors; 9. Superconducting Quantum Interference (SQUIDs); 10. Superconductor Digital Electronics; 11. Other Applications (Josephson arrays as radiation sources. Tunable microwave devices) and 12. Summary and Outlook (of the superconducting devices).

Color superconductivity

International Nuclear Information System (INIS)

Wilczek, F.

1997-01-01

The asymptotic freedom of QCD suggests that at high density - where one forms a Fermi surface at very high momenta - weak coupling methods apply. These methods suggest that chiral symmetry is restored and that an instability toward color triplet condensation (color superconductivity) sets in. Here I attempt, using variational methods, to estimate these effects more precisely. Highlights include demonstration of a negative pressure in the uniform density chiral broken phase for any non-zero condensation, which we take as evidence for the philosophy of the MIT bag model; and demonstration that the color gap is substantial - several tens of MeV - even at modest densities. Since the superconductivity is in a pseudoscalar channel, parity is spontaneously broken

Color superconductivity

Energy Technology Data Exchange (ETDEWEB)

Wilczek, F. [Institute for Advanced Study, Princeton, NJ (United States)

1997-09-22

The asymptotic freedom of QCD suggests that at high density - where one forms a Fermi surface at very high momenta - weak coupling methods apply. These methods suggest that chiral symmetry is restored and that an instability toward color triplet condensation (color superconductivity) sets in. Here I attempt, using variational methods, to estimate these effects more precisely. Highlights include demonstration of a negative pressure in the uniform density chiral broken phase for any non-zero condensation, which we take as evidence for the philosophy of the MIT bag model; and demonstration that the color gap is substantial - several tens of MeV - even at modest densities. Since the superconductivity is in a pseudoscalar channel, parity is spontaneously broken.

The Danish Superconducting Cable Project

DEFF Research Database (Denmark)

Tønnesen, Ole

1997-01-01

The design and construction of a superconducting cable is described. The cable has a room temperature dielectric design with the cryostat placed inside the electrical insulation.BSCCO 2223 superconducting tapes wound in helix form around a former are used as the cable conductor. Results from...

the tj model and superconductivity

African Journals Online (AJOL)

DJFLEX

Perhaps that in the reason why their explanations of the superconductivity have had limited scope . A proper theory and mechanism of superconductivity in the ceramic cuprates should take account of magnetism inherent in the compounds. For the (214) compound experiment have revealed strong antiferromagnetic (AF).

Ac superconducting articles and a method for their manufacture

International Nuclear Information System (INIS)

Meyerhoff, R.W.

1975-01-01

A novel ac superconducting article is described comprising a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface. (auth)

Singular deposit formation in PWR due to electrokinetic phenomena - application to SG clogging

Energy Technology Data Exchange (ETDEWEB)

Guillodo, M.; Muller, T.; Barale, M.; Foucault, M. [AREVA NP SAS, Technical Centre (France); Clinard, M.-H.; Brun, C.; Chahma, F. [AREVA NP SAS, Chemistry and Radiochemistry Group (France); Corredera, G.; De Bouvier, O. [Electricite de France, Centre d' Expertise de I' inspection dans les domaines de la Realisation et de l' Exploitation (France)

2009-07-01

The deposits which cause clogging of the 'foils' of the tube support plates (TSP) in Steam Generators (SG) of PWR present two characteristics which put forward that the mechanism at the origin of their formation is different from the mechanism that drives the formation of homogeneous deposits leading to the fouling of the free spans of SG tubes. Clogging occurs near the leading edge of the TSP and the deposits appear as diaphragms localized between both TSP and SG tubing materials, while the major part of the tube/TSP interstice presents little or no significant clogging. This type of deposit seems rather comparable to the ones which were reproduced in Lab tests to explain the flow rate instabilities observed on a French unit during hot shutdown in the 90's. The deposits which cause TSP clogging are owed to a discontinuity of the streaming currents in the vicinity of a surface singularity (orifices, scratches ...) which, in very low conductivity environment, produce local potential variations and/or current loop in the metallic pipe material due to electrokinetic effects. Deposits can be built by two mechanisms which may or not coexist: (i) accumulation of particles stabilized by an electrostatic attraction due to the local variation of electrokinetic potential, and (ii) crystalline growth of magnetite produced by the oxidation of ferrous ions on the anodic branch of a current loop. Lab investigations carried out by AREVA NP Technical Centre since the end of the 90's showed that this type of deposit occurs when the redox potential is higher than a critical value, and can be gradually dissolved when the potential becomes lower than this value which depends on the 'Material - Chemistry' couple. Special emphasis will be given in this paper to the TSP clogging of SG in PWR secondary coolant dealing particularly with the potential strong effect of electrokinetic phenomena in low conductive environment and in high temperature conditions

Superconductivity: A critical analysis

International Nuclear Information System (INIS)

Sacchetti, Nicola

1997-01-01

It is some forty years now that superconductivity has entered into the field of applied Physics. Countless applications have been proposed some of which have been successfully tested in the form of prototypes and relatively few have become widely used products. This article offers an objective examination of what applied superconductivity represents in the area of modern technology highlighting its exclusive advantages and its inevitable limitations

Superconducting magnets for accelerators

International Nuclear Information System (INIS)

Denisov, Yu.N.

1979-01-01

Expediency of usage and possibilities arising in application of superconducting devices in magnetic systems of accelerators and experimental nuclear-physical devices are studied. Parameters of specific devices are given. It is emphasized that at the existing level of technological possibilities, construction and usage of superconducting magnetic systems in experimental nuclear physics should be thought of as possible, from the engineering, and expedient, from the economical viewpoints [ru

Characterization of a superconducting Pb photocathode in a superconducting rf photoinjector cavity

CERN Document Server

Barday, R; Jankowiak, A; Kamps, T; Knobloch, J; Kugeler, O; Matveenko, A; Neumann, A; Schmeißer, M; Volker, J; Kneisel, P; Nietubyc, R; Schubert S; Smedley J; Sekutowicz, J; Will, I

2014-01-01

Photocathodes are a limiting factor for the next generation of ultrahigh brightness photoinjectors. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting rf gun cavity to measure the quantum efficiency, its spatial distribution, and the work function. We will also discuss how the cathode surface contaminants modify the performance of the photocathode as well as the gun cavity and we discuss the possibilities to remove these contaminants.

Superconducting fault current limiter for railway transport

Energy Technology Data Exchange (ETDEWEB)

Fisher, L. M., E-mail: LMFisher@niitfa.ru; Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V. [National Technical Physics and Automation Research Institute (Russian Federation)

2015-12-15

A resistive switching superconducting fault current limiter (SFCL) for DC networks with voltage of 3.5 kV and nominal current of 2 kA is developed. The SFCL consists of two series-connected units: block of superconducting modules and high-speed vacuum breaker with total disconnection time not more than 8 ms. The results of laboratory tests of superconducting SFCL modules in current limiting mode are presented. The recovery time of superconductivity is experimentally determined. The possibility of application of SFCL on traction substations of Russian Railways is considered.

Superconducting fault current limiter for railway transport

International Nuclear Information System (INIS)

Fisher, L. M.; Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V.

2015-01-01

A resistive switching superconducting fault current limiter (SFCL) for DC networks with voltage of 3.5 kV and nominal current of 2 kA is developed. The SFCL consists of two series-connected units: block of superconducting modules and high-speed vacuum breaker with total disconnection time not more than 8 ms. The results of laboratory tests of superconducting SFCL modules in current limiting mode are presented. The recovery time of superconductivity is experimentally determined. The possibility of application of SFCL on traction substations of Russian Railways is considered

Superconducting analogue electronics for research and industry

International Nuclear Information System (INIS)

Winkler, D

2003-01-01

This paper gives a brief review of superconducting electronics in research and industry. Examples will show how science benefits from the development and how superconducting devices have found their way into industry and to some commercial products. Impact in terms of enabling new research in other fields (e.g. radio astronomy, medicine), in industry (certification, safety, metrology, etc) and in terms of market will be addressed. From the examples, two fields will be emphasized: superconducting detectors for astronomy and the superconducting quantum interference devices (SQUIDs) employed for different applications

Anomalous electron doping independent two-dimensional superconductivity

Science.gov (United States)

Zhou, Wei; Xing, Xiangzhuo; Zhao, Haijun; Feng, Jiajia; Pan, Yongqiang; Zhou, Nan; Zhang, Yufeng; Qian, Bin; Shi, Zhixiang

2017-07-01

Transition metal (Co and Ni) co-doping effects are investigated on an underdoped Ca0.94La0.06Fe2As2 compound. It is discovered that electron doping from substituting Fe with transition metal (TM = Co, Ni) can trigger high-{T}{{c}} superconductivity around 35 K, which emerges abruptly before the total suppression of the innate spin-density-wave/anti-ferromagnetism (SDW/AFM) state. Remarkably, the critical temperature for the high-{T}{{c}} superconductivity remains constant against a wide range of TM doping levels. And the net electron doping density dependence of the superconducting {T}{{c}} based on the rigid band model can be nicely scaled into a single curve for Co and Ni substitutions, in stark contrast to the case of Ba(Fe1-x TM x )2As2. This carrier density independent superconductivity and the unusual scaling behavior are presumably resulted from the interface superconductivity based on the similarity with the interface superconductivity in a La2-x Sr x CuO4-La2CuO4 bilayer. Evidence of the two-dimensional character of the superfluid by angle-resolved magneto-resistance measurements can further strengthen the interface nature of the high-{T}{{c}} superconductivity.

Superconducting bearings for flywheel applications

Energy Technology Data Exchange (ETDEWEB)

Abrahamsen, Asger Bech

2001-05-01

A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found on the applications of superconducting bearings in flywheels. (au)

Superconducting cosmic strings

International Nuclear Information System (INIS)

Chudnovsky, E.M.; Field, G.B.; Spergel, D.N.; Vilenkin, A.

1986-01-01

Superconducting loops of string formed in the early Universe, if they are relatively light, can be an important source of relativistic particles in the Galaxy. They can be observed as sources of synchrotron radiation at centimeter wavelengths. We propose a string model for two recently discovered radio sources, the ''thread'' in the galactic center and the source G357.7-0.1, and predict that the filaments in these sources should move at relativistic speeds. We also consider superheavy superconducting strings, and the possibility that they be observed as extragalactic radio sources

Superconductivity in Washington, D.C

International Nuclear Information System (INIS)

Ritter, D.

1988-01-01

The author provides insights into the federal government's activity in superconductors. He says the President's most important legislative proposal is a change in anti-trust laws to allow businesses to cooperate on joint production ventures. The President has also directed the Department of Energy, the Department of Commerce, the National Aeronautics and Space Administration, the National Science Foundation, and the Department of Defense to establish Superconductivity Research Centers to conduct research and disseminate information. The author says he thinks it is worthwhile to pursue the President's proposal for cooperation with Japan in superconductivity research and development. The author explains why he supports this and other key legislation related to superconductivity. He says if the United States does not do all that it can, as fast as it can, both domestically and internationally, the U.S. could lose the cutting edge of technological and commercial leadership in the latter 20th century and the 21st century. This is what superconductivity represents

Demonstration of superconducting micromachined cavities

Energy Technology Data Exchange (ETDEWEB)

Brecht, T., E-mail: teresa.brecht@yale.edu; Reagor, M.; Chu, Y.; Pfaff, W.; Wang, C.; Frunzio, L.; Devoret, M. H.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

2015-11-09

Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing.

Superconductivity in LiFeAs probed with quasiparticle interference

Energy Technology Data Exchange (ETDEWEB)

Sun, Zhixiang; Nag, Pranab Kumar; Baumann, Danny; Kappenberger, Rhea [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Wurmehl, Sabine [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Institute for Solid State Physics, TU Dresden (Germany); Buechner, Bernd [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Institute for Solid State Physics, TU Dresden (Germany); Center for Transport and Devices, TU Dresden (Germany); Hess, Christian [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Center for Transport and Devices, TU Dresden (Germany)

2016-07-01

In spite of many theoretical and experimental efforts on studying the superconductivity of iron-based high temperature superconductors, the puzzle about LiFeAs's superconducting mechanism and pairing symmetry are still not clear. Here we want to present our low temperature scanning tunneling microscopy results on probing the superconductivity of LiFeAs. By taking conductance spectroscopic maps for both the superconducting state and normal state, we identify the scatterings due to the electron and hole bands close to the Fermi level. We observe a strong indication that the superconducting behavior in the hole bands are important for the formation of superconductivity in LiFeAs. Our results may also shine light on understanding the superconductivity in other iron pnictide superconductors.

Survey of potential applications of superconducting suspensions

International Nuclear Information System (INIS)

Rao, D.K.; Bupara, S.S.

1993-01-01

The purpose of this report is to survey the recent developments in applying the bulk superconductors to mechanical applications. These applications, called superconducting suspensions, can be broadly divided into three groups - Passive Magnetic Bearings, Passive Superconducting Dampers and Active Superconducting Bearings. Basically, passive magnetic bearings utilize bulk superconductors to support a rotating shaft without contact while active superconducting bearings employ superconducting wires. Passive superconducting dampers, on the other hand, dissipate energy from a vibrating component. Over the past one year, dramatic improvements have been made in processing large-size specimens made of high grade bulk superconductors. As a result, they can meet the size requirements and load capacity requirements of many applications. With this size-scale up, one can utilize them in a wider number of applications than what was possible a few years back. At present several organizations have demonstrated the capability of passive magnetic bearings. The targeted applications include miniature cryoturboexpanders, cryoturbopumps, energy storage wheels and turbomolecular pumps. These demonstrations indicate that the passive magnetic bearings are closer to technology maturity. (orig.)

Reluctance motor employing superconducting magnetic flux switches

International Nuclear Information System (INIS)

Spyker, R.L.; Ruckstadter, E.J.

1992-01-01

This paper reports that superconducting flux switches controlling the magnetic flux in the poles of a motor will enable the implementation of a reluctance motor using one central single phase winding. A superconducting flux switch consists of a ring of superconducting material surrounding a ferromagnetic pole of the motor. When in the superconducting state the switch will block all magnetic flux attempting to flow in the ferromagnetic core. When switched to the normal state the superconducting switch will allow the magnetic flux to flow freely in that pole. By using one high turns-count coil as a flux generator, and selectively channeling flux among the various poles using the superconducting flux switch, 3-phase operation can be emulated with a single-hase central AC source. The motor will also operate when the flux generating coil is driven by a DC current, provided the magnetic flux switches see a continuously varying magnetic flux. Rotor rotation provides this varying flux due to the change in stator pole inductance it produces

Nanolayers with advanced properties for superconducting nanoelectronics

International Nuclear Information System (INIS)

Prepelita, A.; Zdravkov, V.; Morari, R.; Socrovisciuc, A.; Antropov, E.; Sidorenko, A.

2011-01-01

Full text: Elaborated advanced technology for superconducting spintronics - technological process, based on magnetron sputtering of the metallic films with non-metallic protective layers, yields significant improvement in superconducting properties of thin Nb films and Nb/CuNi nanostructures in comparison with common methods of films deposition. The developed advanced technological process is patented (Patent RM number 175 from 31.03.2010). First experimental observation of the double re-entrant superconductivity in superconductor/ ferromagnetic nanostructures (Nb/Cu 41 Ni 59 bilayers) in dependence on the thickness of the ferromagnetic layer (Published in : A.S. Sidorenko, V.I. Zdravkov, J. Kehrle, R.Morari, E.Antropov, G. Obermeier, S. Gsell, M. Schreck, C. Muller, V.V. Ryazanov, S. Horn, R. Tidecks, L.R. Tagirov. Extinction and recovery of superconductivity by interference in superconductor/ferromagnet bilayers. In: Nanoscale Phenomena . Fundamentals and Applications,Ed. by H.Hahn, A.Sidorenko, I.Tiginyanu, Springer, 2009 p.1-10. Perspectives of applications: design of a new generation of superconducting spintronic devices - high frequency operating superconducting spin-switch for telecommunication and computers. (author)

Depth Discrimination Using Rg-to-Sg Spectral Amplitude Ratios for Seismic Events in Utah Recorded at Local Distances

Energy Technology Data Exchange (ETDEWEB)

Tibi, Rigobert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Koper, Keith D. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics; Pankow, Kristine L. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics; Young, Christopher J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2018-03-20

Short-period fundamental-mode Rayleigh waves (Rg) are commonly observed on seismograms of anthropogenic seismic events and shallow, naturally occurring tectonic earthquakes (TEs) recorded at local distances. In the Utah region, strong Rg waves traveling with an average group velocity of about 1.8 km/s are observed at ~1 Hz on waveforms from shallow events ( depth<10 km ) recorded at distances up to about 150 km. At these distances, Sg waves, which are direct shear waves traveling in the upper crust, are generally the dominant signals for TEs. Here in this study, we leverage the well-known notion that Rg amplitude decreases dramatically with increasing event depth to propose a new depth discriminant based on Rg-to-Sg spectral amplitude ratios. The approach is successfully used to discriminate shallow events (both earthquakes and anthropogenic events) from deeper TEs in the Utah region recorded at local distances ( <150 km ) by the University of Utah Seismographic Stations (UUSS) regional seismic network. Using Mood’s median test, we obtained probabilities of nearly zero that the median Rg-to-Sg spectral amplitude ratios are the same between shallow events on the one hand (including both shallow TEs and anthropogenic events), and deeper earthquakes on the other, suggesting that there is a statistically significant difference in the estimated Rg-to-Sg ratios between the two populations. We also observed consistent disparities between the different types of shallow events (e.g., mining blasts vs. mining-induced earthquakes), implying that it may be possible to separate the subpopulations that make up this group. Lastly, this suggests that using local distance Rg-to-Sg spectral amplitude ratios one can not only discriminate shallow events from deeper events but may also be able to discriminate among different populations of shallow events.

Superconducting magnet for 'ML-100'

Energy Technology Data Exchange (ETDEWEB)

Saito, R; Fujinaga, T; Tada, N; Kimura, H

1974-07-01

A magneticaly levitated experimental vehicle (Ml-100) was designed and constructed in commemoration of the centenary of the Japanese National Railways. For magnetic levitation the vehicle is provided with two superconducting magnets. In the test operation of the vehicle, these superconducting magnets showed stable performance in levitating vehicle body.

Superconducting magnets for toroidal fusion reactors

International Nuclear Information System (INIS)

Haubenreich, P.N.

1980-01-01

Fusion reactors will soon be employing superconducting magnets to confine plasma in which deuterium and tritium (D-T) are fused to produce usable energy. At present there is one small confinement experiment with superconducting toroidal field (TF) coils: Tokamak 7 (T-7), in the USSR, which operates at 4 T. By 1983, six different 2.5 x 3.5-m D-shaped coils from six manufacturers in four countries will be assembled in a toroidal array in the Large Coil Test Facility (LCTF) at Oak Ridge National Laboratory (ORNL) for testing at fields up to 8 T. Soon afterwards ELMO Bumpy Torus (EBT-P) will begin operation at Oak Ridge with superconducting TF coils. At the same time there will be tokamaks with superconducting TF coils 2 to 3 m in diameter in the USSR and France. Toroidal field strength in these machines will range from 6 to 9 T. NbTi and Nb 3 Sn, bath cooling and forced flow, cryostable and metastable - various designs are being tried in this period when this new application of superconductivity is growing and maturing

Stacked magnet superconducting bearing

International Nuclear Information System (INIS)

Rigney, T.K. II; Saville, M.P.

1993-01-01

A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

Genome Editing for Cancer Therapy: Delivery of Cas9 Protein/sgRNA Plasmid via a Gold Nanocluster/Lipid Core-Shell Nanocarrier.

Science.gov (United States)

Wang, Peng; Zhang, Lingmin; Xie, Yangzhouyun; Wang, Nuoxin; Tang, Rongbing; Zheng, Wenfu; Jiang, Xingyu

2017-11-01

The type II bacterial clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 (CRISPR-associated protein) system (CRISPR-Cas9) is a powerful toolbox for gene-editing, however, the nonviral delivery of CRISPR-Cas9 to cells or tissues remains a key challenge. This paper reports a strategy to deliver Cas9 protein and single guide RNA (sgRNA) plasmid by a nanocarrier with a core of gold nanoclusters (GNs) and a shell of lipids. By modifying the GNs with HIV-1-transactivator of transcription peptide, the cargo (Cas9/sgRNA) can be delivered into cell nuclei. This strategy is utilized to treat melanoma by designing sgRNA targeting Polo-like kinase-1 ( Plk1 ) of the tumor. The nanoparticle (polyethylene glycol-lipid/GNs/Cas9 protein/sgPlk1 plasmid, LGCP) leads to >70% down-regulation of Plk1 protein expression of A375 cells in vitro. Moreover, the LGCP suppresses melanoma progress by 75% on mice. Thus, this strategy can deliver protein-nucleic acid hybrid agents for gene therapy.

{sup 119}Sn-NMR investigations on superconducting Ca{sub 3}Ir{sub 4}Sn{sub 13}: Evidence for multigap superconductivity

Energy Technology Data Exchange (ETDEWEB)

Sarkar, R., E-mail: rajibsarkarsinp@gmail.com [Institute for Solid State Physics, TU Dresden, D-01069 Dresden (Germany); Brückner, F.; Günther, M. [Institute for Solid State Physics, TU Dresden, D-01069 Dresden (Germany); Wang, Kefeng; Petrovic, C. [Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Biswas, P.K.; Luetkens, H.; Morenzoni, E.; Amato, A. [Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Klauss, H-H. [Institute for Solid State Physics, TU Dresden, D-01069 Dresden (Germany)

2015-12-15

We report bulk superconductivity (SC) in Ca{sub 3}Ir{sub 4}Sn{sub 13} by means of {sup 119}Sn nuclear magnetic resonance (NMR) experiments. Two classical signatures of BCS superconductivity in spin-lattice relaxation rate (1/T{sub 1}), namely the Hebel–Slichter coherence peak just below the T{sub c}, and the exponential decay in the superconducting phase, are evident. The noticeable decrease of {sup 119}Sn Knight shift below T{sub c} indicates spin-singlet superconductivity. The temperature dependence of the spin-lattice relaxation rate {sup 119}(1/T{sub 1}) is convincingly described by the multigap isotropic superconducting gap. NMR experiments do not witness any sign of enhanced spin fluctuations.

Superconductivity in Spain. Midas program

International Nuclear Information System (INIS)

Yndurain, F.

1996-01-01

The different activities in the field of applied superconductivity carried out in Spain under the auspices of the MIDAS program are reported. Applications using both low- and high-temperature superconductors are considered. In the low temperature superconductors case, the design and construction of a 1 mega joule SMES (Superconducting Magnetic Energy Storage) unit, as well as the fabrication of voltage and resistance standards, are reviewed. Developments involving the design and fabrication of an inductive current fault limited and mono- and multi-filamentary wires and tapes using high-temperature superconductors are discussed. Finally, the prospects for the application of superconductivity technology to electric power systems for the electric utilities is considered. (author)

Surface and subsurface continuous gravimetric monitoring of groundwater recharge processes through the karst vadose zone at Rochefort Cave (Belgium)

Science.gov (United States)

Watlet, A.; Van Camp, M. J.; Francis, O.; Poulain, A.; Hallet, V.; Triantafyllou, A.; Delforge, D.; Quinif, Y.; Van Ruymbeke, M.; Kaufmann, O.

2017-12-01

Ground-based gravimetry is a non-invasive and integrated tool to characterize hydrological processes in complex environments such as karsts or volcanoes. A problem in ground-based gravity measurements however concerns the lack of sensitivity in the first meters below the topographical surface, added to limited infiltration below the gravimeter building (umbrella effect). Such limitations disappear when measuring underground. Coupling surface and subsurface gravity measurements therefore allow isolating hydrological signals occurring in the zone between the two gravimeters. We present a coupled surface/subsurface continuous gravimetric monitoring of 2 years at the Rochefort Cave Laboratory (Belgium). The gravity record includes surface measurements of a GWR superconducting gravimeter and subsurface measurements of a Micro-g LaCoste gPhone gravimeter, installed in a cave 35 m below the surface station. The recharge of karstic aquifers is extremely complex to model, mostly because karst hydrological systems are composed of strongly heterogeneous flows. Most of the problem comes from the inadequacy of conventional measuring tools to correctly sample such heterogeneous media, and particularly the existence of a duality of flow types infiltrating the vadose zone: from rapid flows via open conduits to slow seepage through porous matrix. Using the surface/subsurface gravity difference, we were able to identify a significant seasonal groundwater recharge within the karst vadose zone. Seasonal or perennial perched reservoirs have already been proven to exist in several karst areas due to the heterogeneity of the porosity and permeability gradient in karstified carbonated rocks. Our gravimetric experiment allows assessing more precisely the recharge processes of such reservoirs. The gravity variations were also compared with surface and in-cave hydrogeological monitoring (i.e. soil moisture, in-cave percolating water discharges, water levels of the saturated zone). Combined

Karst system vadose zone hydrodynamics highlighted by an integrative geophysical and hydrogeological monitoring

Science.gov (United States)

Watlet, A.; Van Camp, M. J.; Francis, O.; Poulain, A.; Hallet, V.; Rochez, G.; Kaufmann, O.

2015-12-01

The vadose zone of karst systems plays an important role on the water dynamics. In particular, temporary perched aquifers can appear in the subsurface due to changes of climate conditions, diminished evapotranspiration and differences of porosity relative to deeper layers. It is therefore crucial, but challenging, to separate the hydrological signature of the vadose zone from the one of the saturated zone for understanding hydrological processes that occur in the vadose zone. Although many difficulties are usually encountered when studying karst environments due to their heterogeneities, cave systems offer an outstanding opportunity to investigate vadose zone from the inside with various techniques. We present results covering two years of hydrogeological and geophysical monitoring at the Rochefort Cave Laboratory (RCL), located in the Variscan fold-and-thrust belt (Belgium), a region that shows many karstic networks within Devonian limestone units. Hydrogeological data such as flows and levels monitoring or tracer tests performed in both vadose and saturated zones bring valuable information on the hydrological context of the studied area. Combining those results with geophysical measurements allows validating and imaging them with more integrative techniques. A microgravimetric monitoring involves a superconducting gravimeter continuously measuring at the surface of the RCL. Early in 2015, a second relative gravimeter was installed in the underlying cave system located 35 meters below the surface. This set up allows highlighting vadose gravity changes. These relative measurements are calibrated using an absolute gravimeter. 12 additional stations (7 at the surface, 5 in the cave) are monitored on a monthly basis by a spring gravimeter. To complete these gravimetric measurements, the site has been equipped with a permanent Electrical Resistivity Tomography (ERT) monitoring system comprising an uncommon array of surface, borehole and cave electrodes. Although such

Accelerators and superconductivity: A marriage of convenience

International Nuclear Information System (INIS)

Wilson, M.

1987-01-01

This lecture deals with the relationship between accelerator technology in high-energy-physics laboratories and the development of superconductors. It concentrates on synchrotron magnets, showing how their special requirements have brought about significant advances in the technology, particularly the development of filamentary superconducting composites. Such developments have made large superconducting accelerators an actuality: the Tevatron in routine operation, the Hadron Electron Ring Accelerator (HERA) under construction, and the Superconducting Super Collider (SSC) and Large Hadron Collider (LHC) at the conceptual design stage. Other applications of superconductivity have also been facilitated - for example medical imaging and small accelerators for industrial and medical use. (orig.)

Superconductivity research in the Czech Republic

Czech Academy of Sciences Publication Activity Database

Jirsa, Miloš

-, č. 1 (2007), s. 1-6 ISSN N Institutional research plan: CEZ:AV0Z10100520 Keywords : superconductivity * research to superconductivity * financial support of the research Subject RIV: BM - Solid Matter Physics ; Magnetism

Design and manufacture of a large superconducting homopolar motor (and status of superconducting a.c. generator)

International Nuclear Information System (INIS)

Appleton, A.D.

1983-01-01

This paper describes the design and manufacture of a large superconducting motor which, in the present time of financial restraints, is continuing at least to the point of having a completed cryostat with its superconducting winding operating with a dedicated helium refrigeration plant. Comments are also made on the superconducting a.c. generator project, although a final decision on the rating of a prototype and the approval of the funding has not yet been made, the selected rating is expected to be between 200 MW and 600 MW

Superconducting rf activities at Cornell University

International Nuclear Information System (INIS)

Padamsee, H.; Hakimi, M.; Kirchgessner, J.

1988-01-01

Development of rf superconductivity for high energy accelerators has been a robust activity at the Cornell Laboratory of Nuclear Studies (LNS) for many years. In order to realize the potential of rf superconductivity, a two-pronged approach has been followed. On the one hand accelerator applications were selected where the existing state-of-the art of superconducting rf is competitive with alternate technologies, then LNS engaged in a program to design, construct and test suitable superconducting cavities, culminating in a full system test in an operating accelerator. On the second front the discovery and invention of ideas, techniques and materials required to make superconducting rf devices approach the ideal in performance has been aggressively pursued. Starting with the development of superconducting cavities for high energy electron synchrotrons, the technology was extended to high energy e + e - storage rings. The LE5 cavity design has now been adopted for use in the Continuous Electron Beam Accelerator Facility (CEBAF). When completed, this project will be one of the largest applications of SRF technology, using 440 LE5 modules[4]. In the last two years, the cavity design and the technology have been transferred to industry and CEBAF. Cornell has tested the early industrial prototypes and cavity pairs. LNS has developed, in collaboration with CEBAF, designs and procedures for cavity pair and cryomodule assembly and testing. Advanced research for future electron accelerators is badly needed if particle physicists hope to expand the energy frontier. Superconducting cavity technology continues to offer attractive opportunities for further advances in achievable voltage at reasonable cost for future accelerators. For Nb, the full potential implies an order of magnitude increase over current capabilities. 20 references, 11 figures

Applied superconductivity and cryogenic research activities in NIFS

International Nuclear Information System (INIS)

Mito, T.; Sagara, A.; Imagawa, S.; Yamada, S.; Takahata, K.; Yanagi, N.; Chikaraishi, H.; Maekawa, R.; Iwamoto, A.; Hamaguchi, S.; Sato, M.; Noda, N.; Yamauchi, K.; Komori, A.; Motojima, O.

2006-01-01

Since the foundation of National Institute for Fusion Science (NIFS) in 1989, the primary mission of the applied superconductivity and cryogenic researches has been focused on the development of the large helical device (LHD): the largest fusion experimental apparatus exclusively utilizing superconducting technologies. The applied superconductivity and cryogenics group in NIFS was organized to be responsible for this activity. As a result of extensive research activities, the construction of LHD was completed in 1997. Since then, the LHD superconducting system has been demonstrating high availability of more than 97% during eight years operation and it keeps proving high reliability of large-scale superconducting systems. This paper describes the extensive activities of the applied superconductivity and cryogenic researches in NIFS during and after the development of LHD and the fundamental researches that aim at realizing a helical-type fusion reactor

Superconducting detectors for semiconductor quantum photonics

International Nuclear Information System (INIS)

Reithmaier, Guenther M.

2015-01-01

In this thesis we present the first successful on-chip detection of quantum light, thereby demonstrating the monolithic integration of superconducting single photon detectors with individually addressable semiconductor quantum dots in a prototypical quantum photonic circuit. Therefore, we optimized both the deposition of high quality superconducting NbN thin films on GaAs substrates and the fabrication of superconducting detectors and successfully integrated these novel devices with GaAs/AlGaAs ridge waveguides loaded with self-assembled InGaAs quantum dots.

Superconducting magnet package for the TESLA test facility

International Nuclear Information System (INIS)

Koski, A.; Bandelmann, R.; Wolff, S.

1996-01-01

The magnetic lattice of the TeV electron superconducting linear accelerator (TESLA) will consist of superconducting quadrupoles for beam focusing and superconducting correction dipoles for beam steering, incorporated in the cryostats containing the superconducting cavities. This report describes the design of these magnets, presenting details of the magnetic as well as the mechanical design. The measured characteristics of the TESLA Test Facility (TTF) quadrupoles and dipoles are compared to the results obtained from numerical computations

Superconducting materials for large scale applications

International Nuclear Information System (INIS)

Dew-Hughes, D.

1975-01-01

Applications of superconductors capable of carrying large current densities in large-scale electrical devices are examined. Discussions are included on critical current density, superconducting materials available, and future prospects for improved superconducting materials. (JRD)

Working on an LHC superconducting cavity

CERN Multimedia

Laurent Guiraud

2000-01-01

The delicate superconducting equipment for CERN’s LHC collider has to be assembled in ultra-clean conditions to safeguard performance. Here we see the power supply being installed on one of the superconducting cavities.

Collective modes in superconducting rhombohedral graphite

Energy Technology Data Exchange (ETDEWEB)

Kauppila, Ville [O.V. Lounasmaa Laboratory, Aalto University (Finland); Hyart, Timo; Heikkilae, Tero [University of Jyvaeskylae (Finland)

2015-07-01

Recently it was realized that coupling particles with a Dirac dispersion (such as electrons in graphene) can lead to a topologically protected state with flat band dispersion. Such a state could support superconductivity with unusually high critical temperatures. Perhaps the most promising way to realize such coupling in real materials is in the surface of rhombohedrally stacked graphite. We consider collective excitations (i.e. the Higgs modes) in surface superconducting rhombohedral graphite. We find two amplitude and two phase modes corresponding to the two surfaces of the graphite where the superconductivity lives. We calculate the dispersion of these modes. We also derive the Ginzburg-Landau theory for this material. We show that in superconducting rhombohedral graphite, the collective modes, unlike in conventional BCS superconductors, give a large contribution to thermodynamic properties of the material.

Inserti abusivi e attribuzioni indifendibili. Spigolando tra gli unica del canzoniere provenzale Sg

Directory of Open Access Journals (Sweden)

Giuseppe Tavani

2015-05-01

Full Text Available The central section of the Occitan songbook kept at the Biblioteca de Catalunya (ms. 146, generally known as Sg since it originally came from Saragossa (from Gil y Gil’s library, continues to prove to be of great interest for the study of the reception of troubadour poetry in Catalan milieux, at a time when a new poetic tradition was taking shape, influenced by the Toulouse tradition of the Consistori de la Gaia Sciensa. These particular circles and period naturally influenced the selection of authors and texts – with the resulting inclusions and exclusions – as well as the accompanying attributions. The latter may in part be due to a tradition that was already corrupt, but also, especially as far as the unica are concerned, to a form of mimetic parasitism, accompanied by a tendency for illicit inclusions in the case of some particular texts for which, as in previous articles, I have tried to point out the degree of ‘impertinence’ and to decide whether to add them to the list of suspects, to place them under interrogation, or – in the most clearly arbitrary cases – to simply remove them. This paper will focus on a planh attributed to Raimbaut de Vaqueiras (394,4a, which Sg shares with Ve-Ag, and on three unica which Sg alone attributes to Giraut de Borneil (242,18a; 52a; 69a.

Superconducting Radio-Frequency Cavities

Science.gov (United States)

Padamsee, Hasan S.

2014-10-01

Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

Superconductivity at high pressures

Energy Technology Data Exchange (ETDEWEB)

Brandt, N B; Ginzburg, N I

1969-07-01

Work published during the last 3 or 4 yrs concerning the effect of pressure on superconductivity is reviewed. Superconducting modifications of Si, Ge, Sb, Te, Se, P and Ce. Change of Fermi surface under pressure for nontransition metals. First experiments on the influence of pressure on the tunneling effect in superconductors provide new information on the nature of the change in phonon and electron energy spectra of metals under hydrostatic compression. 78 references.

Design considerations for superconducting magnets as a maglev pad

International Nuclear Information System (INIS)

Ichikawa, H.; Ogiwara, H.

1974-01-01

The design and construction of a thin superconducting magnet for a magnetically suspended high-speed train are explained. The superconducting magnet, which is to be used in a null-flux maglev train system, is called a 'wing-type' superconducting magnet because of its geometry. The wing-type superconducting magnet is about 1.5m long and weighs about 500kg, but its heat loss is within 1W, which is very small compared with that of conventional superconducting magnets. (author)

Development of sputter ion pump based SG leak detection system for Fast Breeder Test Reactor

International Nuclear Information System (INIS)

Babu, B.; Sureshkumar, K.V.; Srinivasan, G.

2013-01-01

Highlights: ► Development and commissioning of SG leak detection system for FBTR. ► Development of Robust method of using sputter ion pump based system. ► Modifications for improving reliability and availability. ► On line injection of hydrogen in sodium during reactor operation. ► Triplication of the SG leak detection system. - Abstract: The Fast Breeder Test Reactor (FBTR) is a 40 MWt, loop type sodium cooled fast reactor built at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam as a fore-runner to the second stage of Indian nuclear power programme. The reactor design is based on the French reactor Rapsodie with several modifications which include the provision of a steam-water circuit and turbo-generator. FBTR uses sodium as the coolant in the main heat transport medium to transfer heat from the reactor core to the feed water in the tertiary loop for producing superheated steam, which drives the turbo-generator. Sodium and water flow in shell and tube side respectively, separated by thin-walls of the ferritic steel tubes of the once-through steam generator (SG). Material defects in these tubes can lead to leakage of water into sodium, resulting in sodium water reactions leading to undesirable consequences. Early detection of water or steam leaks into sodium in the steam generator units of liquid metal fast breeder reactors (LMFBR) is an important requirement from safety and economic considerations. The SG leak in FBTR is detected by Sputter Ion Pump (SIP) based Steam Generator Leak Detection (SGLD) system and Thermal Conductivity Detector (TCD) based Hydrogen in Argon Detection (HAD) system. Many modifications were carried out in the SGLD system for the reactor operation to improve the reliability and availability. This paper details the development and the acquired experience of SIP based SGLD system instrumentation for real time hydrogen detection in sodium for FBTR.

Some theories of high temperature superconductivity

International Nuclear Information System (INIS)

Cohen, M.L.

1990-01-01

In this paper a brief review is given of some historical aspects of theoretical research on superconductivity including a discussion of BCS theory and some theoretical proposals for mechanisms which can cause superconductivity at high temperatures

Superconducting current generators

International Nuclear Information System (INIS)

Genevey, P.

1970-01-01

After a brief summary of the principle of energy storage and liberation with superconducting coils,two current generators are described that create currents in the range 600 to 1400 A, used for two storage experiments of 25 kJ and 50 kJ respectively. The two current generators are: a) a flux pump and b) a superconducting transformer. Both could be developed into more powerful units. The study shows the advantage of the transformer over the flux pump in order to create large currents. The efficiencies of the two generators are 95 per cent and 40 to 60 per cent respectively. (author) [fr

Exotic Magnetic Orders and Their Interplay with Superconductivity

DEFF Research Database (Denmark)

Christensen, Morten Holm

Superconductivity represents one of the most important scientific discoveries of the 20th century. The practical applications are numerous ranging from clean energy storage and MRI machines to quantum computers. However, the low temperatures required for superconductivity prohibits many practical...... applications. The more recent discovery of high-temperature superconductors, with superconducting transition temperatures above 100~K, has led to the hope that superconductivity at room-temperature might be achievable, although a complete theoretical understanding of the high-temperature superconductors...

Superconductivity

International Nuclear Information System (INIS)

2007-01-01

During 2007, a large amount of the work was centred on the ITER project and related tasks. The activities based on low-temperature superconducting (LTS) materials included the manufacture and qualification of ITER full-size conductors under relevant operating conditions, the design of conductors and magnets for the JT-60SA tokamak and the manufacture of the conductors for the European dipole facility. A preliminary study was also performed to develop a new test facility at ENEA in order to test long-length ITER or DEMO full-size conductors. Several studies on different superconducting materials were also started to create a more complete database of superconductor properties, and also for use in magnet design. In this context, an extensive measurement campaign on transport and magnetic properties was carried out on commercially available NbTi strands. Work was started on characterising MgB 2 wire and bulk samples to optimise their performance. In addition, an intense experimental study was started to clarify the effect of mechanical loads on the transport properties of multi-filamentary Nb 3 Sn strands with twisted or untwisted superconducting filaments. The experimental activity on high-temperature superconducting (HTS) materials was mainly focussed on the development and characterisation of YBa 2 Cu 3 O 7-X (YBCO) based coated conductors. Several characteristics regarding YBCO deposition, current transport performance and tape manufacture were investigated. In the framework of chemical approaches for YBCO film growth, a new method, developed in collaboration with the Technical University of Cluj-Napoca (TUCN), Romania, was studied to obtain YBCO film via chemical solution deposition, which modifies the well-assessed metallic organic deposition trifluoroacetate (MOD-TFA) approach. The results are promising in terms of critical current and film thickness values. YBCO properties in films with artificially added pinning sites were characterised in collaboration with

Superconducting cavities for beauty factories

International Nuclear Information System (INIS)

Lengeler, H.

1992-01-01

The possibilities and merits of superconducting accelerating cavities for Beauty-factories are considered. There exist already large sc systems of size and frequency comparable to the ones needed for Beauty-factories. Their status and operation experience is discussed. A comparison of normal conducting and superconducting systems is done for two typical Beauty-factory rings

Superconducting materials

International Nuclear Information System (INIS)

Kormann, R.; Loiseau, R.; Marcilhac, B.

1989-01-01

The invention concerns superconducting ceramics containing essentially barium, calcium and copper fluorinated oxides with close offset and onset temperatures around 97 K and 100 K and containing neither Y nor rare earth [fr

Method of superconducting joint and its measurement

International Nuclear Information System (INIS)

Kim, Woo Gon; Lee, Ho Jin; Hong, Gye Won

1994-04-01

The development of joint techniques for superconducting wires is essential to fabricate the high quality superconducting magnet. In this report, the various joining methods and their measuring techniques were reviewed. In order to fabricate a precise superconducting magnet, joining and measuring experiment by using the field decay technique carried out. The contact resistance of coupled specimens with joint was measured as 3.0 x 10 -15 ohm at 1 Tesla which is lower than that of the real operating condition of MRI magnet. It is expected that these data can be used to design and fabricate the superconducting magnets successfully. (Author) 12 refs., 20 figs., 2 tabs

Superconducting inductive displacement detection of a microcantilever

Science.gov (United States)

Vinante, A.

2014-07-01

We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 μT, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at 4.2 K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

Pantechnik new superconducting ion source: PantechniK Indian Superconducting Ion Source

International Nuclear Information System (INIS)

Gaubert, G.; Bieth, C.; Bougy, W.; Brionne, N.; Donzel, X.; Leroy, R.; Sineau, A.; Vallerand, C.; Villari, A. C. C.; Thuillier, T.

2012-01-01

The new ECR ion source PantechniK Indian Superconducting Ion Source (PKISIS) was recently commissioned at Pantechnik. Three superconducting coils generate the axial magnetic field configuration, while the radial magnetic field is done with the multi-layer permanent magnets. Special care was devoted to the design of the hexapolar structure, allowing a maximum magnetic field of 1.32 T at the wall of the 82 mm diameter plasma chamber. The three superconducting coils using low temperature superconducting wires are cooled by a single double stage cryo-cooler (4.2 K). Cryogen-free technology is used, providing reliability and easy maintenance at low cost. The maximum installed RF power (18.0 GHz) is of 2 kW. Metallic beams can be produced with an oven (T max = 1400 deg. C) installed with an angle of 5 deg. with respect to the source axis or a sputtering system, mounted on the axis of the source. The beam extraction system is constituted of three electrodes in accel-decel configuration. The new source of Pantechnik is conceived for reaching optimum performances at 18 GHz RF frequencies. PKISIS magnetic fields are 2.1 T axial B inj and 1.32 T radial field in the wall, variable B min with an independent coil and a large and opened extraction region. Moreover, PKISIS integrates modern design concepts, like RF direct injection (2 kW availability), dc-bias moving disk, out-of-axis oven and axial sputtering facility for metal beams. Finally, PKISIS is also conceived in order to operate in a high-voltage platform with minor power consumption.

Magnetization Controlled Superconductivity in a Film with Magnetic Dots

International Nuclear Information System (INIS)

Lyuksyutov, I.F.; Pokrovsky, V.; Pokrovsky, V.

1998-01-01

We consider a superconducting film with a magnetic dots array (MDA) placed upon it. Magnetic moments of the dots are normal to the film and strong enough to create vortices in the superconducting film. Magnetic interaction between dots is negligible. Zero-field cooling leads to random magnetization of the MDA well above the superconducting temperature. With this cooling, the film is in a resistive state below the (expected) superconducting transition. Paradoxically, when field cooled, the film with MDA can be superconducting. copyright 1998 The American Physical Society

Conceptual study of superconducting urban area power systems

International Nuclear Information System (INIS)

Noe, Mathias; Gold-acker, Wilfried; Bach, Robert; Prusseit, Werner; Willen, Dag; Poelchau, Juri; Linke, Christian

2010-01-01

Efficient transmission, distribution and usage of electricity are fundamental requirements for providing citizens, societies and economies with essential energy resources. It will be a major future challenge to integrate more sustainable generation resources, to meet growing electricity demand and to renew electricity networks. Research and development on superconducting equipment and components have an important role to play in addressing these challenges. Up to now, most studies on superconducting applications in power systems have been concentrated on the application of specific devices like for example cables and current limiters. In contrast to this, the main focus of our study is to show the consequence of a large scale integration of superconducting power equipment in distribution level urban power systems. Specific objectives are to summarize the state-of-the-art of superconducting power equipment including cooling systems and to compare the superconducting power system with respect to energy and economic efficiency with conventional solutions. Several scenarios were considered starting from the replacement of an existing distribution level sub-grid up to a full superconducting urban area distribution level power system. One major result is that a full superconducting urban area distribution level power system could be cost competitive with existing solutions in the future. In addition to that, superconducting power systems offer higher energy efficiency as well as a number of technical advantages like lower voltage drops and improved stability.

Development of a superconducting claw-pole motor

International Nuclear Information System (INIS)

Watanabe, E.; Kikukawa, K.; Satoh, Y.; Torii, S.

2008-01-01

We have developed and produced a superconducting claw-pole motor for a trial purpose as a method to make the best use of the characteristic of superconductivity without collector rings or rotating superconducting coils that need to be cryocooled, and made some examinations. The unique feature in this motor is to have the mechanism that supports the reaction magnetic force generated in the axial direction

Development of high field superconducting magnet

International Nuclear Information System (INIS)

Irie, Fujio; Takeo, Masakatsu.

1986-01-01

Recently, in connection with nuclear fusion research, the development of high field superconducting magnets showed rapid progress. The development of high field magnets of 15 T class by the techniques of winding after heat treatment has been continued in various places, as these techniques are suitable to make large magnets. In 1985, Kyushu University attained the record of 15.5 T. However in high field magnets, there are many problems peculiar to them, and the basic research related to those is demanded. In this report, these general problems, the experience of the design and manufacture in Kyushu University and the related problems are described. The superconducting magnet installed in the Superconducting Magnet Research Center of Kyushu University attained the record of 15.5 T for the first time in March, 1985. In superconducting magnets, very difficult problem must be solved since superconductivity, heat and mechanical force are inter related. The problems of the wire materials for high field, the scale of high field magnets, the condition limiting mean current density, and the development of high field magnets in Kyushu University are described. (Kako, I.)

Designing of superconducting magnet for clinical MRI

International Nuclear Information System (INIS)

Kar, Soumen; Choudhury, A.; Sharma, R.G.; Datta, T.S.

2015-01-01

Superconducting technology of Magnetic Resonance Imaging (MRI) scanner is closely guarded technology as it has huge commercial application for clinical diagnostics. This is a rapidly evolving technology which requires innovative design of magnetic and cryogenic system. A project on the indigenous development of 1.5 T (B_0) MRI scanner has been initiated by SAMEER, Mumbai funded by DeitY, Gov. of India. IUAC is the collaborating institute for designing and developing the superconducting magnets and the cryostat for 1.5 T MRI scanner. The superconducting magnet is heart of the present day MRI system. The performance of the magnet has the highest impact on the overall image quality of the scanner. The stringent requirement of the spatial homogeneity (few parts per million within 50 cm diametrical spherical volume), the temporal stability (0.1 ppm/hr.) of the superconducting magnet and the safety standard (5 G in 5 m x 3 m ellipsoidal space) makes the designing of the superconducting magnet more complex. MRI consists of set of main coils and shielding coils. The large ratio between the diameter and the winding length of each coil makes the B_p_e_a_k/B_0 ratio much higher, which makes complexity in selecting the load line of the magnet. Superconducting magnets will be made of NbTi wire-in-channel (WIC) conductor with high copper to superconducting (NbTi) ratio. Multi-coil configuration on multi-bobbin architecture is though is cost effective but poses complexity in the mechanical integration to achieve desired homogeneity. Some of the major sources of inhomogeneities, in a multi-bobbin configuration, are the imperfect axial positioning and angular shift. We have simulated several factors which causes the homogeneity in six (main) coils configuration for a 1.5 T MRI magnet. Differential thermal shrinkage between the bobbin and superconducting winding is also a major source of inhomogeneity in a MRI magnet. This paper briefly present the different designing aspects of the

Tetracritical point and current circulations in superconducting state

International Nuclear Information System (INIS)

Belyavskij, V.I.; Kopaev, Yu.V.; Smirnov, M.Yu.

2005-01-01

Phase diagram reflecting the key peculiar features of the standard diagram of the cuprate superconductors was studied in terms of the Ginzburg-Landau phenomenology near the tetracritical point resulting from the competition of superconducting and dielectric channels of pairing. Two-component parameter of order the relative phase of which is associated with antiferromagnetic dielectric ordering corresponds to the superconducting pairing at repulsion. In case of slight doping the dielectric order coexists with superconductivity below the temperature of superconducting phase transition and manifests itself as a slight pseudoslit above the mentioned temperature. A segment of pseudoslit region adjacent to the superconducting state corresponds to the matured fluctuations of the order parameter in the form of quasi-stationary states of noncoherent superconducting pairs and may be interpreted as a region of a strong pseudoslit. At increase of doping one observes a phase transition from the coexistence region and the orbital antiferromagnetism to the conventional superconducting state covering the region of matured fluctuations of the order parameter in the form of quasi-stationary states of the noncorrelated orbital circulation currents adjacent to the line of phase transition [ru

Superconducting spin switch based on superconductor-ferromagnet nanostructures for spintronics

International Nuclear Information System (INIS)

Kehrle, Jan; Mueller, Claus; Obermeier, Guenter; Schreck, Matthias; Gsell, Stefan; Horn, Siegfried; Tidecks, Reinhard; Zdravkov, Vladimir; Morari, Roman; Sidorencko, Anatoli; Prepelitsa, Andrei; Antropov, Evgenii; Socrovisciiuc, Alexei; Nold, Eberhard; Tagirov, Lenar

2011-01-01

Very rapid developing area, spintronics, needs new devices, based on new physical principles. One of such devices - a superconducting spin-switch, consists of ferromagnetic and superconducting layers, and is based on a new phenomenon - reentrant superconductivity. The tuning of the superconducting and ferromagnetic layers thickness is investigated to optimize superconducting spin-switch effect for Nb/Cu 41 Ni 59 based nanoscale layered systems.

Future development of large superconducting generators

International Nuclear Information System (INIS)

Singh, S.K.; Mole, C.J.

1989-01-01

Large superconducting generators are being developed worldwide. The use of superconductors to reduce the electrical power dissipation in power equipment has been a technological possibility ever since the discovery of superconductivity, even though their use in power equipment remained an impractical dream for a long time. However, scientific and technological progress in superconductivity and cryogenics has brought this dream much closer to reality. Results obtained so far establish the technical feasibility of these machines. Analytical developments have been providing a sound basis for the design of superconducting machines and results of these design studies have shown improvements in power density of up to a factor of 10 higher than the power density for conventional machines. This paper describes the recently completed USA programs, the current foreign and USA programs, and then proposes a USA development program to maintain leadership in the field

Superconducting Electronic Film Structures

Science.gov (United States)

1991-02-14

Segmuller, A., Cooper, E.I., Chisholm, M.F., Gupta, A. Shinde, S., and Laibowitz, R.B. Lanthanum gallate substrates for epitaxial high-T superconducting thin...M. F. Chisholm, A. Gupta, S. Shinde, and R. B. Laibowitz, " Lanthanum Gallate Substrates for Epitaxial High-T c Superconducting Thin Films," Appl...G. Forrester and J. Talvacchio, " Lanthanum Copper Oxide Buffer Layers for Growth of High-T c Superconductor Films," Disclosure No. RDS 90-065, filed

Lattice parameters guide superconductivity in iron-arsenides

Science.gov (United States)

Konzen, Lance M. N.; Sefat, Athena S.

2017-03-01

The discovery of superconducting materials has led to their use in technological marvels such as magnetic-field sensors in MRI machines, powerful research magnets, short transmission cables, and high-speed trains. Despite such applications, the uses of superconductors are not widespread because they function much below room-temperature, hence the costly cooling. Since the discovery of Cu- and Fe-based high-temperature superconductors (HTS), much intense effort has tried to explain and understand the superconducting phenomenon. While no exact explanations are given, several trends are reported in relation to the materials basis in magnetism and spin excitations. In fact, most HTS have antiferromagnetic undoped ‘parent’ materials that undergo a superconducting transition upon small chemical substitutions in them. As it is currently unclear which ‘dopants’ can favor superconductivity, this manuscript investigates crystal structure changes upon chemical substitutions, to find clues in lattice parameters for the superconducting occurrence. We review the chemical substitution effects on the crystal lattice of iron-arsenide-based crystals (2008 to present). We note that (a) HTS compounds have nearly tetragonal structures with a-lattice parameter close to 4 Å, and (b) superconductivity can depend strongly on the c-lattice parameter changes with chemical substitution. For example, a decrease in c-lattice parameter is required to induce ‘in-plane’ superconductivity. The review of lattice parameter trends in iron-arsenides presented here should guide synthesis of new materials and provoke theoretical input, giving clues for HTS.

Superconductivity and fusion energy—the inseparable companions

Science.gov (United States)

Bruzzone, Pierluigi

2015-02-01

Although superconductivity will never produce energy by itself, it plays an important role in energy-related applications both because of its saving potential (e.g., power transmission lines and generators), and its role as an enabling technology (e.g., for nuclear fusion energy). The superconducting magnet’s need for plasma confinement has been recognized since the early development of fusion devices. As long as the research and development of plasma burning was carried out on pulsed devices, the technology of superconducting fusion magnets was aimed at demonstrations of feasibility. In the latest generation of plasma devices, which are larger and have longer confinement times, the superconducting coils are a key enabling technology. The cost of a superconducting magnet system is a major portion of the overall cost of a fusion plant and deserves significant attention in the long-term planning of electricity supply; only cheap superconducting magnets will help fusion get to the energy market. In this paper, the technology challenges and design approaches for fusion magnets are briefly reviewed for past, present, and future projects, from the early superconducting tokamaks in the 1970s, to the current ITER (International Thermonuclear Experimental Reactor) and W7-X projects and future DEMO (Demonstration Reactor) projects. The associated cryogenic technology is also reviewed: 4.2 K helium baths, superfluid baths, forced-flow supercritical helium, and helium-free designs. Open issues and risk mitigation are discussed in terms of reliability, technology, and cost.

Preliminary study on AC superconducting machines

International Nuclear Information System (INIS)

Yamamoto, M.; Ishigohka, T.; Shimohka, T.; Mizukami, N.; Yamaguchi, M.

1988-01-01

This paper describes the issues involved in developing AC superconducting machines. In the first phase, as a preliminary experiment, a 4kVa AC superconducting coil which employs 100A class 50/60Hz superconductors is made and tested. And, in the second phase, as an extension of the 4kVa coil, a model superconducting transformer is made and examined. The transformer has a novel quench protection system with an auxiliary coil only in the low voltage side. The behavior of the overcurrent protection system is confirmed

Availability verification of information for human system interface in automatic SG level control using activity diagram

Energy Technology Data Exchange (ETDEWEB)

Nuraslinda, Anuar; Kim, Dong Young; Kim, Jong Hyun [KEPCO International Nuclear Graduate School, Uljugun (Korea, Republic of)

2012-10-15

Steam Generator (SG) level control system in OPR 1000 is one of representative automatic systems that falls under the Supervisory Control level in Endsley's taxonomy. Supervisory control of automated systems is classified as a form of out of the loop (OOTL) performance due to passive involvement in the systems operation, which could lead to loss of situation awareness (SA). There was a reported event, which was caused by inadequate human automation communication that contributed to an unexpected reactor trip in July 2005. A high SG level trip occurred in Yeonggwang (YGN) Unit 6 Nuclear Power Plant (NPP) due to human operator failure to recognize the need to change the control mode of the economizer valve controller (EVC) to manual mode during swap over (the transition from low power mode to high power mode) after the loss of offsite power (LOOP) event was recovered. This paper models the human system interaction in NPP SG level control system using Unified Modeling Language (UML) Activity Diagram. Then, it identifies the missing information for operators in the OPR1000 Main Control Room (MCR) and suggests some means of improving the human system interaction.

Availability verification of information for human system interface in automatic SG level control using activity diagram

International Nuclear Information System (INIS)

Nuraslinda, Anuar; Kim, Dong Young; Kim, Jong Hyun

2012-01-01

Steam Generator (SG) level control system in OPR 1000 is one of representative automatic systems that falls under the Supervisory Control level in Endsley's taxonomy. Supervisory control of automated systems is classified as a form of out of the loop (OOTL) performance due to passive involvement in the systems operation, which could lead to loss of situation awareness (SA). There was a reported event, which was caused by inadequate human automation communication that contributed to an unexpected reactor trip in July 2005. A high SG level trip occurred in Yeonggwang (YGN) Unit 6 Nuclear Power Plant (NPP) due to human operator failure to recognize the need to change the control mode of the economizer valve controller (EVC) to manual mode during swap over (the transition from low power mode to high power mode) after the loss of offsite power (LOOP) event was recovered. This paper models the human system interaction in NPP SG level control system using Unified Modeling Language (UML) Activity Diagram. Then, it identifies the missing information for operators in the OPR1000 Main Control Room (MCR) and suggests some means of improving the human system interaction

Superconductivity in the elements, alloys and simple compounds

Energy Technology Data Exchange (ETDEWEB)

Webb, G.W. [Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319 (United States); Marsiglio, F. [Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2E1 (Canada); Hirsch, J.E., E-mail: jhirsch@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319 (United States)

2015-07-15

Highlights: • A review of superconductivity in elements, alloys and simple compounds is given. • These materials are believed to be described by BCS–Eliashberg theory. • The McMillan–Rowell inversion process is described. • Calculations of Tc’s from first principles are surveyed. • Other criteria beyond BCS to characterize these superconductors are discussed. - Abstract: We give a brief review of superconductivity at ambient pressure in elements, alloys, and simple three-dimensional compounds. Historically these were the first superconducting materials studied, and based on the experimental knowledge gained from them the BCS theory of superconductivity was developed in 1957. Extended to include the effect of phonon retardation, the theory is believed to describe the subset of superconducting materials known as ‘conventional superconductors’, where superconductivity is caused by the electron–phonon interaction. These include the elements, alloys and simple compounds discussed in this article and several other classes of materials discussed in other articles in this Special Issue.

Superconductivity in the elements, alloys and simple compounds

International Nuclear Information System (INIS)

Webb, G.W.; Marsiglio, F.; Hirsch, J.E.

2015-01-01

Highlights: • A review of superconductivity in elements, alloys and simple compounds is given. • These materials are believed to be described by BCS–Eliashberg theory. • The McMillan–Rowell inversion process is described. • Calculations of Tc’s from first principles are surveyed. • Other criteria beyond BCS to characterize these superconductors are discussed. - Abstract: We give a brief review of superconductivity at ambient pressure in elements, alloys, and simple three-dimensional compounds. Historically these were the first superconducting materials studied, and based on the experimental knowledge gained from them the BCS theory of superconductivity was developed in 1957. Extended to include the effect of phonon retardation, the theory is believed to describe the subset of superconducting materials known as ‘conventional superconductors’, where superconductivity is caused by the electron–phonon interaction. These include the elements, alloys and simple compounds discussed in this article and several other classes of materials discussed in other articles in this Special Issue

Manufacture of keystoned flat superconducting cables for use in SSC [Superconducting Super Collider] dipoles

International Nuclear Information System (INIS)

Royet, J.; Scanlan, R.M.

1986-09-01

The superconducting magnets used in the construction of particle accelerators are mostly built from flat, multistrand cables with rectangular or keystoned cross sections. In this paper we will emphasize the differences between the techniques for cabling conventional wires for cabling superconducting wires. Concepts for the tooling will be introduced. The effects of cabling parameters on critical current degradation are being evaluated in collaboration with NBS-Boulder

Ceramic/metal and A15/metal superconducting composite materials exploiting the superconducting proximity effect and method of making the same

International Nuclear Information System (INIS)

Holcomb, M.J.

1999-01-01

A composite superconducting material made of coated particles of ceramic superconducting material and a metal matrix material is disclosed. The metal matrix material fills the regions between the coated particles. The coating material is a material that is chemically nonreactive with the ceramic. Preferably, it is silver. The coating serves to chemically insulate the ceramic from the metal matrix material. The metal matrix material is a metal that is susceptible to the superconducting proximity effect. Preferably, it is a NbTi alloy. The metal matrix material is induced to become superconducting by the superconducting proximity effect when the temperature of the material goes below the critical temperature of the ceramic. The material has the improved mechanical properties of the metal matrix material. Preferably, the material consists of approximately 10% NbTi, 90% coated ceramic particles (by volume). Certain aspects of the material and method will depend upon the particular ceramic superconductor employed. An alternative embodiment of the invention utilizes A15 compound superconducting particles in a metal matrix material which is preferably a NbTi alloy

Ceramic/metal and A15/metal superconducting composite materials exploiting the superconducting proximity effect and method of making the same

Science.gov (United States)

Holcomb, Matthew J.

1999-01-01

A composite superconducting material made of coated particles of ceramic superconducting material and a metal matrix material. The metal matrix material fills the regions between the coated particles. The coating material is a material that is chemically nonreactive with the ceramic. Preferably, it is silver. The coating serves to chemically insulate the ceramic from the metal matrix material. The metal matrix material is a metal that is susceptible to the superconducting proximity effect. Preferably, it is a NbTi alloy. The metal matrix material is induced to become superconducting by the superconducting proximity effect when the temperature of the material goes below the critical temperature of the ceramic. The material has the improved mechanical properties of the metal matrix material. Preferably, the material consists of approximately 10% NbTi, 90% coated ceramic particles (by volume). Certain aspects of the material and method will depend upon the particular ceramic superconductor employed. An alternative embodiment of the invention utilizes A15 compound superconducting particles in a metal matrix material which is preferably a NbTi alloy.

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.

A two-phase full-wave superconducting rectifier

International Nuclear Information System (INIS)

Ariga, T.; Ishiyama, A.

1989-01-01

A two-phase full-wave superconducting rectifier has been developed as a small cryogenic power supply of superconducting magnets for magnetically levitation trains. Those magnets are operated in the persistent current mode. However, small ohmic loss caused at resistive joints and ac loss induced by the vibration of the train cannot be avoided. Therefore, the low-power cryogenic power supply is required to compensate for the reduction in magnet current. The presented superconducting rectifier consists of two identical full-wave rectifiers connected in series. Main components of each rectifier are a troidal shape superconducting set-up transformer and two thermally controlled switches. The test results using a 47.5 mH load magnet at 0.2 Hz and 0.5 Hz operations are described. To estimate the characteristics of the superconducting rectifier, the authors have developed a simulation code. From the experiments and the simulations, the transfer efficiency is examined. Furthermore, the optimal design of thermally controlled switches based on the finite element analysis is also discussed

Development of innovative superconducting DC power cable

Energy Technology Data Exchange (ETDEWEB)

Matsushita, Teruo; Kiuchi, Masaru [Dept. of Computer Science and Electronics Kyushu Institute of Technology, Iizuka (Japan)

2017-09-15

It is required to reduce the cost of superconducting cable to realize a superconducting DC power network that covers a wide area in order to utilize renewable energy. In this paper a new concept of innovative cable is introduced that can enhance the current-carrying capacity even though the same superconducting tape is used. Such a cable can be realized by designing an optimal winding structure in such a way that the angle between the tape and magnetic field becomes small. This idea was confirmed by preliminary experiments for a single layer model cable made of Bi-2223 tapes and REBCO coated conductors. Experiments of three and four layer cables of practical sizes were also done and it was found that the current-carrying capacity increased as theoretically predicted. If the critical current properties of commercial superconducting tapes are further improved in a parallel magnetic field, the enhancement will become pronounced and this technology will surely contribute to realization of superconducting DC power network.

Proposed experimental test of the theory of hole superconductivity

Energy Technology Data Exchange (ETDEWEB)

Hirsch, J.E., E-mail: jhirsch@ucsd.edu

2016-06-15

Highlights: • The conventional theory of superconductivity predicts no charge flow when the normal-superconductor phase boundary moves. • The theory of hole superconductivity predicts flow and counterflow of charge. • An experiment to measure a voltage is proposed. • No voltage will be measured if the conventional theory is correct. • A voltage will be measured if the theory of hole superconductivity is correct. - Abstract: The theory of hole superconductivity predicts that in the reversible transition between normal and superconducting phases in the presence of a magnetic field there is charge flow in direction perpendicular to the normal-superconductor phase boundary. In contrast, the conventional BCS-London theory of superconductivity predicts no such charge flow. Here we discuss an experiment to test these predictions.

Plugging criteria for WWER SG tubes

Energy Technology Data Exchange (ETDEWEB)

Papp, L.; Wilam, M. [Vitkovice NPP Services (Switzerland); Herman, M. [Vuje, Trnava (Slovakia)

1997-12-31

At operated Czech and Slovak nuclear power plants the 80 % criteria for crack or other bulk defect depth is used for steam generator heat exchanging tubes plugging. This criteria was accepted as the recommendation of designer of WWER steam generators. Verification of this criteria was the objective of experimental program performed by Vitkovice, J.S.C., UJV Rez, J.S.C. and Vuje Trnava, J.S.C .. Within this program the following factors were studied: (1) Influence of secondary water chemistry on defects initiation and propagation, (2) Statistical evaluation of corrosion defects progression at operated SG, and (3) Determination of critical pressure for tube rupture as a function of eddy current indications. In this presentation items (2) and (3) are considered.

Plugging criteria for WWER SG tubes

Energy Technology Data Exchange (ETDEWEB)

Papp, L; Wilam, M [Vitkovice NPP Services (Switzerland); Herman, M [Vuje, Trnava (Slovakia)

1998-12-31

At operated Czech and Slovak nuclear power plants the 80 % criteria for crack or other bulk defect depth is used for steam generator heat exchanging tubes plugging. This criteria was accepted as the recommendation of designer of WWER steam generators. Verification of this criteria was the objective of experimental program performed by Vitkovice, J.S.C., UJV Rez, J.S.C. and Vuje Trnava, J.S.C .. Within this program the following factors were studied: (1) Influence of secondary water chemistry on defects initiation and propagation, (2) Statistical evaluation of corrosion defects progression at operated SG, and (3) Determination of critical pressure for tube rupture as a function of eddy current indications. In this presentation items (2) and (3) are considered.

Contribution to the study of superconducting magnets using high transition temperature superconducting materials

International Nuclear Information System (INIS)

Lecrevisse, Thibault

2012-01-01

The new industrial superconductors using high critical temperature compounds offer new possibilities for superconducting magnetism. Indeed they allow higher magnetic field with the same classical cryogenics at 4.2 K on one hand, and on the other hand they also pave the way for superconducting magnets working between 10 K and 30 K. The high temperature superconductors are then needed in order to produce magnetic fields higher than 16 T (case of HTS dipole insert for Large Hadron Collider at CERN) or to increase the specific density stored in one SMES (Superconducting Magnetic Energy Storage, in the case of the SuperSMES ANR Project).Nevertheless the indisputable assets (critical temperature, critical magnetic field, mechanical stresses) brought by the use of High critical temperature superconductors like YBCO, used in superconducting magnets, require to solve some challenges. Their behavior is still badly understood, especially during the resistive transitions. To succeed in protecting these conductors we need a new reflection on protection schemes designed to avoid the thermal and mechanical damages. The answer to the question: 'Can we use those materials in the long run inside superconducting magnets?' is now inescapable.Some answers are given here. The use of the conductors is approached through various experimental studies to understand the material (electrical characterization and modeling of the critical surface) and to define the key stages of high critical temperature superconducting magnets manufacturing (work on the junctions between conductors and pancakes). This study led to the creation of two coils in order to identify the issues related to the use of YBCO tapes. A numerical thermo-electrical model of the high critical temperature superconductor has been developed and a numerical code based on the CEA software CASTEM (Finish Elements Model) allowed to study the resistive transition (or quench) behavior of those conductor and coil. The code has been

Modern aspects of Josephson dynamics and superconductivity electronics

CERN Document Server

Askerzade, Iman; Cantürk, Mehmet

2017-01-01

In this book new experimental investigations of properties of Josephson junctions and systems are explored with the help of recent developments in superconductivity. The theory of the Josephson effect is presented taking into account the influence of multiband and anisotropy effects in new superconducting compounds. Anharmonicity effects in current-phase relation on Josephson junctions dynamics are discussed. Recent studies in analogue and digital superconductivity electronics are presented. Topics of special interest include resistive single flux quantum logic in digital electronics. Application of Josephson junctions in quantum computing as superconducting quantum bits are analyzed. Particular attention is given to understanding chaotic behaviour of Josephson junctions and systems. The book is written for graduate students and researchers in the field of applied superconductivity.

Gossamer superconductivity, new paradigm?

Energy Technology Data Exchange (ETDEWEB)

Won, Hyekyung [Department of Physics, Hallym University, Chuncheon 200-702 (Korea); Haas, Stephan; Parker, David [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Maki, Kazumi [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Max-Planck Institute for the Physics of Complex Systems, Noethnitzer Str. 38, 01187 Dresden (Germany); Dora, Balazs [Department of Physics, Budapest University of Technology and Economics, 1521 Budapest (Hungary); Virosztek, Attila [Department of Physics, Budapest University of Technology and Economics, 1521 Budapest (Hungary); Research Institute for Solid State Physics and Optics, P.O. Box 49, 1525 Budapest (Hungary)

2006-01-01

We review our recent works on d-wave density wave (dDW) and gossamer superconductivity (i.e. d-wave superconductivity in the presence of dDW) in high-T{sub c} cuprates and CeCoIn{sub 5}. a) We show that both the giant Nernst effect and the angle dependent magnetoresistance (ADMR) in the pseudogap phases of the cuprates and CeCoIn{sub 5} are manifestations of dDW. b) The phase diagram of high-T{sub c} cuprates is understood in terms of mean field theory, which includes two order parameters {delta}{sub 1} and {delta}{sub 2}, where one order paremeter is from dDW and the other from d-wave superconductivity. c) In the optimally to the overdoped region we find the spatially periodic dDW, an analogue of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, becomes more stable. d) In the underdoped region where {delta}{sub 2}/{delta}{sub 1}<<1 the Uemera relation is obtained within the present model. We speculate that the gossamer superconductivity is at the heart of high-T{sub c} cuprate superconductors, the heavy-fermion superconductor CeCoIn{sub 5} and the organic superconductors {kappa}-(ET){sub 2}Cu(NCS){sub 2} and (TMTSF){sub 2}PF{sub 6}. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Quantum suppression of superconductivity in nanowires

International Nuclear Information System (INIS)

Bezryadin, Alexey

2008-01-01

It is of fundamental importance to establish whether there is a limit to how thin a superconducting wire can be, while retaining its superconducting character-and if there is such limit, to understand what determines it. This issue may be of practical importance in defining the limit to miniaturization of superconducting electronic circuits. Recently, a new fabrication method, called molecular templating, was developed and used to answer such questions. In this approach, a suspended carbon nanotube is coated with a thin superconducting metal film, thus forming a superconducting nanowire. The wire obtained is automatically attached to the two leads formed by the sides of the trench. The usual material for such wires is the amorphous alloy of MoGe (Graybeal 1985 PhD Thesis Stanford University; Graybeal and Beasley 1984 Phys. Rev. B 29 4167; Yazdani and Kapitulnik 1995 Phys. Rev. Lett. 74 3037; Turneaure et al 2000 Phys. Rev. Lett. 84 987). Such wires typically exhibit a high degree of homogeneity and can be made very small: as thin as ∼5 nm in diameter and as short as ∼40 nm in length. The results of transport measurements on such homogeneous wires can be summarized as follows. Short wires, shorter than some empirical length, ∼200 nm for MoGe, exhibit a clear dichotomy. They show either a superconducting behavior, with the resistance controlled by thermal fluctuations, or a weakly insulating behavior, with the resistance controlled by the weak Coulomb blockade. Thus a quantum superconductor-insulator transition (SIT) is indicated. Longer wires exhibit a gradual crossover behavior, from almost perfectly superconducting to normal or weakly insulating behavior, as their diameter is reduced. Measurements of wires, which are made inhomogeneous (granular) on purpose, show that such wires, even if they are short in the sense stated above, do not show a clear dichotomy, which could be identified as an SIT (Bollinger et al 2004 Phys. Rev. B 69 180503(R)). Thus

Dimensionality Driven Enhancement of Ferromagnetic Superconductivity in URhGe

Science.gov (United States)

Braithwaite, Daniel; Aoki, Dai; Brison, Jean-Pascal; Flouquet, Jacques; Knebel, Georg; Nakamura, Ai; Pourret, Alexandre

2018-01-01

In most unconventional superconductors, like the high-Tc cuprates, iron pnictides, or heavy-fermion systems, superconductivity emerges in the proximity of an electronic instability. Identifying unambiguously the pairing mechanism remains nevertheless an enormous challenge. Among these systems, the orthorhombic uranium ferromagnetic superconductors have a unique position, notably because magnetic fields couple directly to ferromagnetic order, leading to the fascinating discovery of the reemergence of superconductivity in URhGe at a high field. Here we show that uniaxial stress is a remarkable tool allowing the fine-tuning of the pairing strength. With a relatively small stress, the superconducting phase diagram is spectacularly modified, with a merging of the low- and high-field superconducting states and a significant enhancement of the superconductivity. The superconducting critical temperature increases both at zero field and under a field, reaching 1 K, more than twice higher than at ambient pressure. This enhancement of superconductivity is shown to be directly related to a change of the magnetic dimensionality detected from an increase of the transverse magnetic susceptibility: In addition to the Ising-type longitudinal ferromagnetic fluctuations, transverse magnetic fluctuations also play an important role in the superconducting pairing.

CRISPRpred: A flexible and efficient tool for sgRNAs on-target activity prediction in CRISPR/Cas9 systems.

Directory of Open Access Journals (Sweden)

Md Khaledur Rahman

Full Text Available The CRISPR/Cas9-sgRNA system has recently become a popular tool for genome editing and a very hot topic in the field of medical research. In this system, Cas9 protein is directed to a desired location for gene engineering and cleaves target DNA sequence which is complementary to a 20-nucleotide guide sequence found within the sgRNA. A lot of experimental efforts, ranging from in vivo selection to in silico modeling, have been made for efficient designing of sgRNAs in CRISPR/Cas9 system. In this article, we present a novel tool, called CRISPRpred, for efficient in silico prediction of sgRNAs on-target activity which is based on the applications of Support Vector Machine (SVM model. To conduct experiments, we have used a benchmark dataset of 17 genes and 5310 guide sequences where there are only 20% true values. CRISPRpred achieves Area Under Receiver Operating Characteristics Curve (AUROC-Curve, Area Under Precision Recall Curve (AUPR-Curve and maximum Matthews Correlation Coefficient (MCC as 0.85, 0.56 and 0.48, respectively. Our tool shows approximately 5% improvement in AUPR-Curve and after analyzing all evaluation metrics, we find that CRISPRpred is better than the current state-of-the-art. CRISPRpred is enough flexible to extract relevant features and use them in a learning algorithm. The source code of our entire software with relevant dataset can be found in the following link: https://github.com/khaled-buet/CRISPRpred.

A current controlled variable delay superconducting transmission line

International Nuclear Information System (INIS)

Anlage, S.M.; Snortland, H.J.; Beasley, M.R.

1989-01-01

The authors present a device concept for a current-controlled variable delay for superconducting transmission line. The device makes use of the change in kinetic inductance of a superconducting transmission line under the application of a DC bias current. The relevant materials parameters and several promising superconducting materials have been identified

A study on the effect of tantalum-impurity content on the superconducting properties of niobium materials used for making superconducting radio frequency cavities

Science.gov (United States)

Roy, S. B.; Sharath Chandra, L. S.; Chattopadhyay, M. K.; Tiwari, M. K.; Lodha, G. S.; Myneni, G. R.

2012-11-01

Niobium materials in highly pure form are used in the fabrication of superconducting radio frequency cavities. We present here a study of the superconducting properties of such niobium materials that have been used in the fabrication of high accelerating gradient superconducting radio frequency cavities after determining their tantalum-impurity contents using a synchrotron-based x-ray fluorescence spectroscopy technique. Our results show that there is a small change in superconducting parameters such as TC,HC1 and HC2 when the tantalum-impurity content varies from ≈150 to ≈1300 ppm. In contrast, a buffered chemical polishing of the same niobium samples changes all these superconducting parameters more significantly. The implications of these results on the performance of niobium superconducting radio frequency cavities are discussed.

Test equipment for a flywheel energy storage system using a magnetic bearing composed of superconducting coils and superconducting bulks

International Nuclear Information System (INIS)

Ogata, M; Matsue, H; Yamashita, T; Hasegawa, H; Nagashima, K; Maeda, T; Matsuoka, T; Mukoyama, S; Shimizu, H; Horiuchi, S

2016-01-01

Energy storage systems are necessary for renewable energy sources such as solar power in order to stabilize their output power, which fluctuates widely depending on the weather. Since ‘flywheel energy storage systems’ (FWSSs) do not use chemical reactions, they do not deteriorate due to charge or discharge. This is an advantage of FWSSs in applications for renewable energy plants. A conventional FWSS has capacity limitation because of the mechanical bearings used to support the flywheel. Therefore, we have designed a superconducting magnetic bearing composed of a superconducting coil stator and a superconducting bulk rotor in order to solve this problem, and have experimentally manufactured a large scale FWSS with a capacity of 100 kWh and an output power of 300 kW. The superconducting magnetic bearing can levitate 4 tons and enables the flywheel to rotate smoothly. A performance confirmation test will be started soon. An overview of the superconducting FWSS is presented in this paper. (paper)

Generalized Superconductivity. Generalized Levitation

International Nuclear Information System (INIS)

Ciobanu, B.; Agop, M.

2004-01-01

In the recent papers, the gravitational superconductivity is described. We introduce the concept of generalized superconductivity observing that any nongeodesic motion and, in particular, the motion in an electromagnetic field, can be transformed in a geodesic motion by a suitable choice of the connection. In the present paper, the gravitoelectromagnetic London equations have been obtained from the generalized Helmholtz vortex theorem using the generalized local equivalence principle. In this context, the gravitoelectromagnetic Meissner effect and, implicitly, the gravitoelectromagnetic levitation are given. (authors)

Superconducting RF for energy-recovery linacs

International Nuclear Information System (INIS)

Liepe, M.; Knobloch, J.

2006-01-01

Since superconducting RF for particle accelerators made its first appearance in the 1970s, it has found highly successful application in a variety of machines. Recent progress in this technology has made so-called Energy-Recovery Linacs (ERLs)-originally proposed in 1965-feasible, and interest in this type of machine has increased enormously. A superconducting linac is the driving heart of ERLs, and emittance preservation and cost efficiency is of utmost importance. The resulting challenges for the superconducting cavity technology and RF field control are manifold. In March 2005 the first international workshop on ERLs was held at Newport News, VA, to explore the potential of ERLs and to discuss machine-physics and technology challenges and their solutions. This paper reviews the state-of-the-art in superconducting RF and RF control for ERLs, and summarizes the discussions of the SRF working group on this technology during the ERL2005 workshop

Radiation considerations for superconducting fusion magnets

International Nuclear Information System (INIS)

Abdou, M.A.

1977-01-01

Radiation environment for the magnets is characterized for various conditions expected for tokamak power reactor operation. The radiation levels are translated into radiation effects using available experimental data. The impact of the tradeoffs in radiation shielding and the change in the properties of the superconducting magnets on reactor performance and economics is examined. It is shown that (1) superconducting magnets in fusion reactors will operate at much higher radiation level than was previously anticipated; (2) additional data on radiation damage is required to better accuracy than is presently available in order to accurately quantify the change in properties in the superconducting magnet components; and (3) there is a substantial penalty for increasing (or overestimating) the shielding requirements. A perspective of future tokamak power reactors is presented and questions relating to desirable magnetic field strength and selection of materials for superconducting magnets are briefly examined

Superconducting magnets in high energy physics

International Nuclear Information System (INIS)

Prodell, A.G.

1978-01-01

The applications of superconducting magnets in high energy physics in the last ten years have made feasible developments which are vital to high energy research. These developments include high magnetic field, large volume detectors, such as bubble chambers, required for effective resolution of high energy particle trajectories, particle beam transport magnets, and superconducting focusing and bending magnets for the very high energy accelerators and storage rings needed to pursue the study of interactions between elementary particles. The acceptance of superconductivity as a proven technology in high energy physics was reinforced by the recognition that the existing large accelerators using copper-iron magnets had reached practical limits in terms of magnetic field intensity, cost, space, and energy usage, and that large-volume, high-field, copper-iron magnets were not economically feasible. Some of the superconducting magnets and associated systems being used in and being developed for high energy physics are described

Stable superconducting magnet. [high current levels below critical temperature

Science.gov (United States)

Boom, R. W. (Inventor)

1967-01-01

Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training.

Fundamental of cryogenics (for superconducting RF technology)

CERN Document Server

Pierini, Paolo

2013-01-01

This review briefly illustrates a few fundamental concepts of cryogenic engineering, the technological practice that allows reaching and maintaining the low-temperature operating conditions of the superconducting devices needed in particle accelerators. To limit the scope of the task, and not to duplicate coverage of cryogenic engineering concepts particularly relevant to superconducting magnets that can be found in previous CAS editions, the overview presented in this course focuses on superconducting radio-frequency cavities.

Development of Nb-Ti multifilamentar superconducting wires

International Nuclear Information System (INIS)

Otubo, J.

1986-01-01

Ni-Ti superconducting wires with multifilamentar configuration were produced, using the grouping technique. Some basic concepts on superconductivity and its main critical parameters are presented. The criteria for stabilizing superconductors in terms of the geometry are studied. The main critical parameters, H c , J c , T c in function of the composition and the metallurgical structure of Ni-Ti alloy are analysed. The development of Ni-Ti superconducting wires is described. (M.C.K.) [pt

Spontaneous fluxoid formation in superconducting loops

DEFF Research Database (Denmark)

Monaco, R.; Mygind, Jesper; Rivers, R.

2009-01-01

We report on the experimental verification of the Zurek-Kibble scenario in an isolated superconducting ring over a wide parameter range. The probability of creating a single flux quantum spontaneously during the fast normal-superconducting phase transition of a wide Nb loop clearly follows...

Josephson plasma resonance in superconducting multilayers

DEFF Research Database (Denmark)

Pedersen, Niels Falsig; Sakai, S

1998-01-01

We derive an analytical solution for the Josephson plasma resonance of superconducting multilayers. This analytical solution is derived mainly for low-T-c systems with magnetic coupling between the superconducting layers. but many features of our results are more general, and thus an application...

Novel superconducting state in ferromagnetic superconductor UCoGe. Microscopic coexistence of ferromagnetism and superconductivity probed by 59Co-NQR measurements

International Nuclear Information System (INIS)

Ishida, Kenji; Hattori, Taisuke; Ihara, Yoshihiko; Nakai, Yusuke; Sato, Noriaki K.; Deguchi, Kazuhiko; Tamura, Nobuyuki; Satoh, Isamu

2010-01-01

We have investigated the relationship between ferromagnetism and superconductivity in ferromagnetic superconductor UCoGe from 59 Co nuclear quadrupole resonance (NQR) measurements. Our experimental results indicate the microscopic coexistence of ferromagnetism and superconductivity in UCoGe, and suggest a 'self-induced vortex state' in its superconducting state. We also review NQR experiments, which play an important role in this study. (author)

Impurity effects in superconducting UPt3

International Nuclear Information System (INIS)

Aronson, M.C.; Vorenkamp, T.; Koziol, Z.; de Visser, A.; Bakker, K.; Franse, J.J.M.; Smith, J.L.

1991-01-01

Superconducting UPt 3 is characterized by a novel and complex magnetic field-temperature phase diagram, with two superconducting transitions at T c1 and T c2 in zero field. We have studied the effects of Pd and Y impurities on the zero field superconducting properties of UPt 3 . Resistance measurements show that both dopants increase the residual resistivity and decrease the spin fluctuation temperature in the normal state. T c1 is depressed by both dopants, but more effectively by Pd. |T c1 - T c2 | is essentially unaffected by Y doping, but increases dramatically with Pd doping

Superconductivity in high energy particle accelerators

International Nuclear Information System (INIS)

Schmueser, P.

2002-08-01

The basics of superconductivity are outlined with special emphasis on the features which are relevant for the application in magnets and radio frequency cavities for high energy particle accelerators. The special properties of superconducting accelerator magnets are described in detail: design principles, magnetic field calculations, magnetic forces, quench performance, persistent magnetization currents and eddy currents. The design principles and basic properties of superconducting cavities are explained as well as the observed performance limitations and the countermeasures. The ongoing research efforts towards maximum accelerating fields are addressed and the coupling of radio frequency power to the particle beam is treated. (orig.)

Changes of superconducting interaction in interfaces

International Nuclear Information System (INIS)

Halbritter, J.

1976-01-01

The leakage of conduction electrons from metals into dielectric or semiconducting coatings yields changes in electron phonon coupling and hybridization with localized states in the coating. The changed electron-phonon coupling explains the observed strengthened superconducting interaction with some monolayer thick coating. The hybridization with localized states, i.e. resonance scattering, yields pair weakening and hence a monotonic depression of superconductivity with coating thickness in agreement with experiments. The latter effect explains quantitatively the Tsub(c) and Δ depression (Δ/kTsub(c) approximately equal to const) and a decrease in the Maki-Thompson-fluctuation term observed with thin superconducting films. (author)

Secondary circuit water chemistry and related problems with SG

Energy Technology Data Exchange (ETDEWEB)

Ignatov, V; Ivanov, V [Balakovo Nuclear Power Plant (Russian Federation)

2001-07-01

Necessity for SG feed water and blowdown systems modernization Balakovo NPP steam generators PGV-1000M was identified at Units with VVER-1000 during commissioning separational, thermo-hydraulic and thermo-chemical testings. It was discovered, that in zone of 'hot' header coolant salt concentration (concentration of dissolved salts) was almost 2 times more, than salt concentration in blowdown water. A number of chemical testings was performed to investigate and optimize salts distribution in water volume of PGV-1000. (R.P.)

Secondary circuit water chemistry and related problems with SG

International Nuclear Information System (INIS)

Ignatov, V.; Ivanov, V.

2001-01-01

Necessity for SG feed water and blowdown systems modernization Balakovo NPP steam generators PGV-1000M was identified at Units with VVER-1000 during commissioning separational, thermo-hydraulic and thermo-chemical testings. It was discovered, that in zone of 'hot' header coolant salt concentration (concentration of dissolved salts) was almost 2 times more, than salt concentration in blowdown water. A number of chemical testings was performed to investigate and optimize salts distribution in water volume of PGV-1000. (R.P.)

A study on the effect of tantalum-impurity content on the superconducting properties of niobium materials used for making superconducting radio frequency cavities

International Nuclear Information System (INIS)

Roy, S B; Sharath Chandra, L S; Chattopadhyay, M K; Tiwari, M K; Lodha, G S; Myneni, G R

2012-01-01

Niobium materials in highly pure form are used in the fabrication of superconducting radio frequency cavities. We present here a study of the superconducting properties of such niobium materials that have been used in the fabrication of high accelerating gradient superconducting radio frequency cavities after determining their tantalum-impurity contents using a synchrotron-based x-ray fluorescence spectroscopy technique. Our results show that there is a small change in superconducting parameters such as T C ,H C1 and H C2 when the tantalum-impurity content varies from ≈150 to ≈1300 ppm. In contrast, a buffered chemical polishing of the same niobium samples changes all these superconducting parameters more significantly. The implications of these results on the performance of niobium superconducting radio frequency cavities are discussed. (paper)

Analysis of Mechanical Stresses/Strains in Superconducting Wire

Science.gov (United States)

Barry, Matthew; Chen, Jingping; Zhai, Yuhu

2016-10-01

The optimization of superconducting magnet performance and development of high-field superconducting magnets will greatly impact the next generation of fusion devices. A successful magnet development, however, relies deeply on the understanding of superconducting materials. Among the numerous factors that impact a superconductor's performance, mechanical stress is the most important because of the extreme operation temperature and large electromagnetic forces. In this study, mechanical theory is used to calculate the stresses/strains in typical superconducting strands, which consist of a stabilizer, a barrier, a matrix and superconducting filaments. Both thermal loads and mechanical loads are included in the analysis to simulate operation conditions. Because this model simulates the typical architecture of major superconducting materials, such as Nb3Sn, MgB2, Bi-2212 etc., it provides a good overall picture for us to understand the behavior of these superconductors in terms of thermal and mechanical loads. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internship (SULI) program.

The present role of superconductivity in fusion

International Nuclear Information System (INIS)

Shimamoto, S.

1986-01-01

After completion of large fusion devices in the world, such as JT-60, JET and TFTR, high temperature plasma is proceeding to critical condition for fusion. The devices up to now use mainly conventional magnet. However, for the next generation machine which demonstrates fusion reaction, deuterium-tritium burning, superconducting magnet system is indispensable from view point of both net energy extraction and capacity limitation of power supply. In order to realize such a large and complicated system, a lot of development works is being carried out. This paper describes required parameters of superconducting magnet and helium refrigerator, the state of plasma condition and superconducting magnet. It is shown that the present technology of superconducting magnet is not so far from realization of fusion experimental reactor

On superconductivity and superfluidity. A scientific autobiography

International Nuclear Information System (INIS)

Ginzburg, Vitaly L.

2009-01-01

This book presents the Nobel Laureate Vitaly Ginzburg's views on the development in the field of superconductivity. It contains a selection of Ginzburg's key writings, including his amended version of the Nobel lecture in Physics 2003. Also included are an expanded autobiography, which was written for the Nobel Committee, an article entitled ''A Scientific Autobiography: An Attempt,'' a fundamental article co-written with L.D. Landau entitled ''To the theory of superconductivity,'' an expanded review article ''Superconductivity and superfluidity (what was done and what was not done),'' and some newly written short articles about superconductivity and related subjects. So, in toto, presented here are the personal contributions of Ginzburg, that resulted in the Nobel Prize, in the context of his scientific biography. (orig.)

On superconductivity and superfluidity a scientific autobiography

CERN Document Server

Ginzburg, Vitalii Lazarevich

2009-01-01

This book presents the Nobel Laureate Vitaly Ginzburg's views on the development in the field of superconductivity. It contains a selection of Ginzburg's key writings, including his amended version of the Nobel lecture in Physics 2003. Also included are an expanded autobiography, which was written for the Nobel Committee, an article entitled "A Scientific Autobiography: An Attempt," a fundamental article co-written with L.D. Landau entitled "To the theory of superconductivity," an expanded review article "Superconductivity and superfluidity (what was done and what was not done)," and some newly written short articles about superconductivity and related subjects. So, in toto, presented here are the personal contributions of Ginzburg, that resulted in the Nobel Prize, in the context of his scientific biography.

Superconducting linear accelerator system for NSC

Indian Academy of Sciences (India)

This paper reports the construction of a superconducting linear accelerator as a booster to the 15 UD Pelletron accelerator at Nuclear Science Centre, New Delhi. The LINAC will use superconducting niobium quarter wave resonators as the accelerating element. Construction of the linear accelerator has progressed ...

Superconductivity in domains with corners

DEFF Research Database (Denmark)

Bonnaillie-Noel, Virginie; Fournais, Søren

2007-01-01

We study the two-dimensional Ginzburg-Landau functional in a domain with corners for exterior magnetic field strengths near the critical field where the transition from the superconducting to the normal state occurs. We discuss and clarify the definition of this field and obtain a complete...... asymptotic expansion for it in the large $\\kappa$ regime. Furthermore, we discuss nucleation of superconductivity at the boundary....

Meissner effect in superconducting microtraps

OpenAIRE

Cano, Daniel

2009-01-01

This thesis investigates the impact of the Meissner effect on magnetic microtraps for ultracold atoms near superconducting microstructures. This task has been accomplished both theoretically and experimentally. The Meissner effect distorts the magnetic fields near superconducting surfaces, thus altering the parameters of magnetic microtraps. Both computer simulations and experimental measurements demonstrate that the Meissner effect shortens the distance between the magnetic microtrap and the...

Realization of superconductive films by screen printing

International Nuclear Information System (INIS)

Baudry, H.

1988-01-01

Screen printing is a promising method to manufacture superconductive lines making use of superconductive ceramics. An ink has been realized with YBa 2 Cu 3 0 7-x' and the process conditions defined by thermal analysis. A superconductive transition is observed after screen printing on MgO. The firing of the layer is made at 920 0 C followed by a reoxidation step at 420 0 C. The silver electrical contacts are also screen printed [fr

Superconductivity and structure of gallium under nanoconfinement

Energy Technology Data Exchange (ETDEWEB)

Charnaya, E V; Tien, Cheng; Lee, Min Kai [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Kumzerov, Yu A [A F Ioffe Physico-Technical Institute RAS, St Petersburg, 194021 (Russian Federation)

2009-11-11

Superconductivity and crystalline structure were studied for two nanocomposites consisting of gallium loaded porous glasses with different pore sizes. The superconducting transition temperatures were found to differ from those in known bulk gallium modifications. The transition temperatures 7.1 and 6.7 K were ascribed to two new confined gallium structures, iota- and kappa-Ga, observed by synchrotron radiation x-ray powder diffraction. The evolution of superconductivity on decreasing the pore filling with gallium was also studied.

Laser patterning of superconducting oxide films

International Nuclear Information System (INIS)

Gupta, A.; Hussey, B.W.; Koren, G.; Cooper, E.I.; Jagannathan, R.

1988-01-01

The focused output of an argon ion laser (514.5 nm) has been used for wiring superconducting lines of Y/sub 1/Ba/sub 2/CU/sub 3/O/sub 7-δ/ using films prepared from nitrate and trifluoroacetate solution precursors. A stoichiometric solution of the precursors is sprayed or spun on to the substrate to form a film. The film is patterned by irradiating in selected areas to convert the irradiated layers to an intermediate oxide or fluoride state, the nonirradiated areas being unchanged. The nonirradiated areas are then dissolved away, leaving a pattern of the oxide or fluoride material. This patterned layer is converted to the superconducting 1-2-3 oxide in a subsequent annealing step. Maskless patterning of superconducting films has also been demonstrated by laser-assisted etching of the films in aqueous KOH solution. Although superconductivity is destroyed when the films are placed in solution, it can be restored after a brief anneal in oxygen

Centenary of the discovery of superconductivity

CERN Multimedia

Anaïs Vernède

2011-01-01

To mark the centenary of the discovery of the phenomenon of superconductivity, MANEP and the University of Geneva are organising open days at the PhysiScope between 8 and 15 April 2011. On 13 April CERN will make a contribution to the series of events with a lecture on superconductivity followed by a demonstration of the phenomenon at the Globe   Historic graph showing the superconducting transition of mercury, measured in Leiden in 1911 by H. Kamerlingh Onnes. On 8 April 2011 it will be a hundred years since the discovery of superconductivity by the Dutch physicist Kamerlingh Onnes. To mark the occasion, the University of Geneva and MANEP are organising a week-long interactive workshop at the PhysiScope. “The purpose of this initiative is to introduce the general public to this spectacular phenomenon by giving them an opportunity to take part in entertaining experiments”, explains Adriana Aleman, Head of Communications of the University of Geneva. As its contribution to the e...

New Fast Response Thin Film-Based Superconducting Quench Detectors

CERN Document Server

Dudarev, A; van de Camp, W; Ravaioli, E; Teixeira, A; ten Kate, H H J

2014-01-01

Quench detection on superconducting bus bars and other devices with a low normal zone propagation velocity and low voltage build-up is quite difficult with conventional quench detection techniques. Currently, on ATLAS superconducting bus bar sections, superconducting quench detectors (SQD) are mounted to detect quench events. A first version of the SQD essentially consists of an insulated superconducting wire glued to a superconducting bus line or windings, which in the case of a quench rapidly builds up a relatively high resistance that can be easily and quietly detected. We now introduce a new generation of drastically improved SQDs. The new version makes the detection of quenches simpler, more reliable, and much faster. Instead of a superconducting wire, now a superconducting thin film is used. The layout of the sensor shows a meander like pattern that is etched out of a copper coated 25 mu m thick film of Nb-Ti glued in between layers of Kapton. Since the sensor is now much smaller and thinner, it is easi...

Beam tests and operation of superconducting cavities

International Nuclear Information System (INIS)

Akai, Kazunori

1990-01-01

Beam tests and operation of superconducting cavities conducted since the third workshop on RF superconductivity (Argonne, Sep. 1987) are reported in this paper. The paper is concerned particularly with electron machines. Storage and acceleration of the beam are discussed, focusing on the CERN test in SPS, the DESY test in PETRA, the superconducting injector at Darmstadt, and the KEK beam tests in T-AR. Then, long-term performance of the cavity in the ring is discussed focusing on Eacc (max) and O-value, environmental conditions, and operational experience in T-MR. RF controllability is addressed, centering on the Robinson stability, cavity tuning loop, quench detection and interlocks, recovery procedure, field calibration, and phase adjustment. Higher order modes are also discussed. Superconducting cavities have been operated successfully in accelerators. It has been confirmed that the superconducting cavities can be used stably for experimental use. For more than 5000 hours the cavities have indicated no essential degradation of the cavity performance. The study of long-term performance should be continued in longer range of period. (N.K.)

Superconducting materials

International Nuclear Information System (INIS)

Ruvalds, J.

1990-01-01

This report discusses the following topics: Fermi liquid nesting in high temperature superconductors; optical properties of high temperature superconductors; Hall effect in superconducting La 2-x Sr x CuO 4 ; source of high transition temperatures; and prospects for new superconductors

Normal and superconducting metals at microwave frequencies-classic experiments

International Nuclear Information System (INIS)

Dheer, P.N.

1999-01-01

A brief review of experimental and theoretical work on the behaviour of normal and superconducting materials at microwave frequencies before the publication of Bardeen, Cooper and Schrieffer's theory of superconductivity is given. The work discussed is mostly that of Pippard and his coworkers. It is shown that these investigations lead not only to a better understanding of the electrodynamics of normal and superconducting state but also of the nature of the superconducting state itself. (author)

Sweeping a persisting superconducting magnet with a transformer

International Nuclear Information System (INIS)

Spencer, G.F.; Alexander, P.W.; Ihas, G.G.

1982-01-01

A method for sweeping a persisting superconducting magnet is described. The field sweep is achieved by including in the superconducting loop of the magnet a coil which acts as the secondary coil of a transformer. Variation of the current in the primary coil of the transformer, controlled from outside the cryostat, causes the field-sweeping action through flux-linking with the superconducting loop. Compared to directly changing the current in a magnet, this technique improves control by the ratio of the magnet's inductance to the transformer's inductance. The advantages of using an all-metal vacuum-tight superconducting feedthrough are discussed. (author)

Strapdown Airborne Gravimetry Quality Assessment Method Based on Single Survey Line Data: A Study by SGA-WZ02 Gravimeter

Science.gov (United States)

Wu, Meiping; Cao, Juliang; Zhang, Kaidong; Cai, Shaokun; Yu, Ruihang

2018-01-01

Quality assessment is an important part in the strapdown airborne gravimetry. Root mean square error (RMSE) evaluation method is a classical way to evaluate the gravimetry quality, but classical evaluation methods are preconditioned by extra flight or reference data. Thus, a method, which is able to largely conquer the premises of classical quality assessment methods and can be used in single survey line, has been developed in this paper. According to theoretical analysis, the method chooses the stability of two horizontal attitude angles, horizontal specific force and vertical specific force as the determinants of quality assessment method. The actual data, collected by SGA-WZ02 from 13 flights 21 lines in certain survey, was used to build the model and elaborate the method. To substantiate the performance of the quality assessment model, the model is applied in extra repeat line flights from two surveys. Compared with internal RMSE, standard deviation of assessment residuals are 0.23 mGal and 0.16 mGal in two surveys, which shows that the quality assessment method is reliable and stricter. The extra flights are not necessary by specially arranging the route of flights. The method, summarized from SGA-WZ02, is a feasible approach to assess gravimetry quality using single line data and is also suitable for other strapdown gravimeters. PMID:29373535

LLNL superconducting magnets test facility

Energy Technology Data Exchange (ETDEWEB)

Manahan, R; Martovetsky, N; Moller, J; Zbasnik, J

1999-09-16

The FENIX facility at Lawrence Livermore National Laboratory was upgraded and refurbished in 1996-1998 for testing CICC superconducting magnets. The FENIX facility was used for superconducting high current, short sample tests for fusion programs in the late 1980s--early 1990s. The new facility includes a 4-m diameter vacuum vessel, two refrigerators, a 40 kA, 42 V computer controlled power supply, a new switchyard with a dump resistor, a new helium distribution valve box, several sets of power leads, data acquisition system and other auxiliary systems, which provide a lot of flexibility in testing of a wide variety of superconducting magnets in a wide range of parameters. The detailed parameters and capabilities of this test facility and its systems are described in the paper.

Insulation systems for superconducting transmission cables

DEFF Research Database (Denmark)

Tønnesen, Ole

1996-01-01

the electrical insulation is placed outside both the superconducting tube and the cryostat. The superconducting tube is cooled by liquid nitrogen which is pumped through the hollow part of the tube.2) The cryogenic dielectric design, where the electrical insulation is placed inside the cryostat and thus is kept...

Superconductivity: Is there a problem in transuranics?

International Nuclear Information System (INIS)

Colineau, Eric; Griveau, Jean-Christophe; Eloirdi, Rachel; Hen, Amir; Caciuffo, Roberto

2014-01-01

Superconductivity was first reported in 1942 for uranium metal (¡-U) and in 1958 for U compounds: UCo, U6Mn, U6Fe, and U6Co, with critical temperatures Tc, of 1.7, 2.3, 3.9, and 2.3K, respectively. A new class of U superconductors emerged in the early 1980’s with the discovery of U heavy fermion superconductors : UBe13 (Tc = 0.85K), UPt3 (Tc = 0.53K), URu2Si2 (Tc = 1.5K) , UPd2Al3 (Tc = 1.9K) … Furthermore, in most of these systems, the superconducting phases coexist with antiferromagnetic (AF) correlations which have characteristic temperatures, usually the Néel temperature TN, that are typically one order of magnitude greater than the corresponding superconducting critical temperatures Tc. Superconductivity was even shown to co-exist with ferromagnetism in e.g. UGe2 (Tc ï» 0.8K, TC ï» 30K at p ï» 1.2GPa) and URhGe (Tc = 0.25K, TC = 9.5K). Heavy fermion superconductors still remain a major challenge for condensed matter physics. The existence of heavy fermion superconductivity and its coexistence or proximity with magnetic order suggests that the conventional mechanism of phonon-mediated superconductivity is inappropriate and that alternative mechanisms, like spin fluctuations, should be considered for Cooper pairing

The integration of cryogenic cooling systems with superconducting electronic systems

International Nuclear Information System (INIS)

Green, Michael A.

2003-01-01

The need for cryogenic cooling has been critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of the superconducting circuit is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a disadvantage. This report will talk about the various methods for refrigerating superconducting devices. Cryocooler types will be compared for vibration, efficiency, and cost. Some solutions to specific problems of integrating cryocoolers to superconducting devices are presented.

Levitation properties of superconducting magnetic bearings using superconducting coils and bulk superconductors

Energy Technology Data Exchange (ETDEWEB)

Arai, Yuuki; Seino, Hiroshi; Nagashima, Ken [Railway Technical Research Institute, 2-8-38 Hikari-cho, Kokubunji-shi, Tokyo 185-8540 (Japan)

2010-11-15

We have been developing a flywheel energy storage system (FESS) with 36 MJ energy capacity for a railway system with superconducting magnetic bearings (SMBs). We prepared two kinds of models using superconducting coils and bulk superconductors (SCs). One model demonstrated SMB load capacity of 20 kN and the other model proved non-contact stable levitation and non-contact rotation with SMBs. Combining these results, the feasibility of a 36 MJ energy capacity FESS with SMBs completely inside a cryostat has been confirmed. In this paper, we report the levitation properties of SMBs in these models.

Levitation properties of superconducting magnetic bearings using superconducting coils and bulk superconductors

International Nuclear Information System (INIS)

Arai, Yuuki; Seino, Hiroshi; Nagashima, Ken

2010-01-01

We have been developing a flywheel energy storage system (FESS) with 36 MJ energy capacity for a railway system with superconducting magnetic bearings (SMBs). We prepared two kinds of models using superconducting coils and bulk superconductors (SCs). One model demonstrated SMB load capacity of 20 kN and the other model proved non-contact stable levitation and non-contact rotation with SMBs. Combining these results, the feasibility of a 36 MJ energy capacity FESS with SMBs completely inside a cryostat has been confirmed. In this paper, we report the levitation properties of SMBs in these models.

Design, Assembly, Integration, and Testing of a Power Processing Unit for a Cylindrical Hall Thruster, the NORSAT-2 Flatsat, and the Vector Gravimeter for Asteroids Instrument Computer

Science.gov (United States)

Svatos, Adam Ladislav

This thesis describes the author's contributions to three separate projects. The bus of the NORSAT-2 satellite was developed by the Space Flight Laboratory (SFL) for the Norwegian Space Centre (NSC) and Space Norway. The author's contributions to the mission were performing unit tests for the components of all the spacecraft subsystems as well as designing and assembling the flatsat from flight spares. Gedex's Vector Gravimeter for Asteroids (VEGA) is an accelerometer for spacecraft. The author's contributions to this payload were modifying the instrument computer board schematic, designing the printed circuit board, developing and applying test software, and performing thermal acceptance testing of two instrument computer boards. The SFL's cylindrical Hall effect thruster combines the cylindrical configuration for a Hall thruster and uses permanent magnets to achieve miniaturization and low power consumption, respectively. The author's contributions were to design, build, and test an engineering model power processing unit.

Growth inhibition of head and neck squamous cell carcinoma cells by sgRNA targeting the cyclin D1 mRNA based on TRUE gene silencing.

Directory of Open Access Journals (Sweden)

Satoshi Iizuka

Full Text Available Head and neck squamous cell carcinoma (HNSCC exhibits increased expression of cyclin D1 (CCND1. Previous studies have shown a correlation between poor prognosis of HNSCC and cyclin D1 overexpression. tRNase ZL-utilizing efficacious gene silencing (TRUE gene silencing is one of the RNA-mediated gene expression control technologies that have therapeutic potential. This technology is based on a unique enzymatic property of mammalian tRNase ZL, which is that it can cleave any target RNA at any desired site by recognizing a pre-tRNA-like complex formed between the target RNA and an artificial small guide RNA (sgRNA. In this study, we designed several sgRNAs targeting human cyclin D1 mRNA to examine growth inhibition of HNSCC cells. Transfection of certain sgRNAs decreased levels of cyclin D1 mRNA and protein in HSC-2 and HSC-3 cells, and also inhibited their proliferation. The combination of these sgRNAs and cisplatin showed more than additive inhibition of cancer cell growth. These findings demonstrate that TRUE gene silencing of cyclin D1 leads to inhibition of the growth of HNSCC cells and suggest that these sgRNAs alone or combined with cisplatin may be a useful new therapy for HNSCCs.

High-Tc cuprate superconductivity in a nutshell

International Nuclear Information System (INIS)

Won, Hyekyung; Haas, Stephan; Parker, David; Maki, Kazumi

2005-01-01

Since the discovery of high-T c cuprate superconductivity in 1986 many new experimental techniques and theoretical concepts have been developed. In particular it was shown that the BCS theory of d-wave superconductivity describes semi-quantitatively the high-T c superconductivity. Furthermore, it was demonstrated that Volovik's approach is extremely useful for finding the quasiparticle properties in the vortex state. Here we survey these developments and forecast future directions. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Field quality of LHC superconducting dipole magnets

International Nuclear Information System (INIS)

Mishra, R.K.

2003-01-01

The author reports here the main results of field measurements performed so far on the LHC superconducting dipoles at superfluid helium temperature. The main field strength at injection, collision conditions and higher order multipoles are discussed. Superconducting magnets exhibit additional field imperfections due to diamagnetic properties of superconducting cables, apart from geometric error, saturation of iron yoke and eddy currents error. Dynamic effects on field harmonics, such as field decay at injection and subsequent snap back are also discussed. (author)

Technology of RF superconductivity

International Nuclear Information System (INIS)

Anon.

1995-01-01

This work has several parts, two of which are collaborative development projects with the majority of the work being performed at Argonne. The first is the development of a superconducting RFQ structure in collaboration with AccSys Technology Inc. of Pleasanton, California, funded as a Phase II SBIR grant. Another is a collaborative project with the Nuclear Science Centre, New Delhi, India (who are funding the work) to develop new superconducting ion accelerating structures. Other initiatives are developing various aspects of the technology required to utilize ATLAS as a secondary beam linac for radioactive beams

Contamination issues in superconducting cavity technology

International Nuclear Information System (INIS)

Kneisel, Peter

1997-01-01

The application of radio-frequency superconductivity technology in particle accelerator projects has become increasingly evident in recent years. Several large scale projects around the world are either completed or close to completion, such as CEBAF, HERA, TRISTAN and LEP. And superconducting cavity technology is seriously being considered for future applications in linear colliders (TESLA), high current proton accelerators (APT, spallation neutron sources), muon colliders and free electron lasers for industrial application. The reason for this multitude of activities are matured technology based on a better understanding of the phenomena encountered in superconducting cavities and the influence of improved material properties and contamination and quality control measures

Reviews of large superconducting machines: Metallurgy, fabrication, and applications

International Nuclear Information System (INIS)

Bogner, G.

1981-01-01

This paper reviews large superconducting machines presently in place or in experiment. The ''Cello'' particle detector magnet for the positron-electron colliding beam facility PETRA at DESY in Hamburg is shown, and the Fermi Lab, and the Brookhaven ISABELLE also described. Electrodynamic levitation systems are specified, as researched and developed in Germany and Japan. Of superconducting coils for magnetic separation, a high gradient magnetic separator with superconducting magnet and steel wool, and a Jones type high gradient magnetic separator are schematicized. Turbogenerators with superconductor field winding are studied. Superconducting high power cables include the flexible coaxial cable core consisting of a perforated polyethylene tube and test cables at Siemens and at Brookhaven. Magnet systems for fusion reactors include tokamaks and tandem mirrors, and the toroidal coil experiment at Oak Ridge National Laboratory is described, among others. Superconducting magnets for MHD plants, and superconducting magnet energy storage (SME storage) are also discussed

Superconducting generators and motors and methods for employing same

Energy Technology Data Exchange (ETDEWEB)

Tomsic, Michael J.; Long, Larry

2017-08-29

A superconducting electrical generator or motor having a plurality of cryostats is described. The cryostats contain coolant and a first cryostat encloses at least one of a plurality of superconducting coils. A first coil is in superconducting electrical communication with a second coil contained in a second cryostat through a superconducting conduction cooling cable enclosing a conductor. The first cryostat and the second cryostat may be in fluid communication through at least one cryogen channel within the at least one superconducting conduction cooling cable. In other embodiments, none of the plurality of cryostats may be in fluid communication and the cable may be cooled by conduction along the conductor from the first or second cryostat, or from both. The conductor may have different segments at temperatures equal to or above the temperature of the coolant and the superconducting conduction cooling cables may be connected through quick connect fittings.

Itinerant-electron antiferromagnetism and superconductivity in bcc Cr-Re alloys

International Nuclear Information System (INIS)

Nishihara, Y.; Yamaguchi, Y.; Kohara, T.; Tokumoto, M.

1985-01-01

The magnetic and superconducting properties of bcc Cr-Re alloys with up to 40 at. % Re were studied via measurements of the magnetic susceptibility, electrical resistivity, and nuclear magnetic resonance of the Re nuclei. Antiferromagnetic order coexists with superconductivity above 18 at. % Re. The results were analyzed with the coexistence model of spin-density waves and superconductivity. In the Re-concentration range greater than 18 at. %, about 10% of the Fermi surface satisfies the nesting condition and the rest of it contributes to form the superconducting gap. This model also explains the increase in the superconducting transition temperature and the decrease in the magnetic susceptibility by annealing as a competing effect between spin-density waves and superconductivity

Superconducting technology program Sandia 1996 annual report

International Nuclear Information System (INIS)

Roth, E.P.

1997-02-01

Sandia's Superconductivity Technology Program is a thallium-based high-temperature superconductor (HTS) research and development program consisting of efforts in powder synthesis and process development, open-system thick film conductor development, wire and tape fabrication, and HTS motor design. The objective of this work is to develop high-temperature superconducting conductors (wire and tape) capable of meeting requirements for high-power electrical devices of interest to industry. The research efforts currently underway are: (1) Process development and characterization of thallium-based high-temperature superconducting closed system wire and tape, (2) Investigation of the synthesis and processing of thallium-based thick films using two-zone processing, and (3) Cryogenic design of a 30K superconducting motor. This report outlines the research that has been performed during FY96 in each of these areas

On superconductivity and superfluidity. A scientific autobiography

Energy Technology Data Exchange (ETDEWEB)

Ginzburg, Vitaly L. [Russian Academy of Sciences, Moscow (Russian Federation). P.N. Lebedev Physical Inst.

2009-07-01

This book presents the Nobel Laureate Vitaly Ginzburg's views on the development in the field of superconductivity. It contains a selection of Ginzburg's key writings, including his amended version of the Nobel lecture in Physics 2003. Also included are an expanded autobiography, which was written for the Nobel Committee, an article entitled 'A Scientific Autobiography: An Attempt,' a fundamental article co-written with L.D. Landau entitled 'To the theory of superconductivity,' an expanded review article 'Superconductivity and superfluidity (what was done and what was not done),' and some newly written short articles about superconductivity and related subjects. So, in toto, presented here are the personal contributions of Ginzburg, that resulted in the Nobel Prize, in the context of his scientific biography. (orig.)

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

Conceptual design report: superconducting booster

International Nuclear Information System (INIS)