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1

JT-60 Control System  

SciTech Connect

The present status of the JT-60U control system is reported including its original design concept, the progress of the system, and various modifications since the JT-60 upgrade. This control system has features of a functionally distributed and hierarchical structure, using CAMAC interfaces initially, which have been replaced by versatile module Europe (VME)-bus interfaces, and a protective interlock system composed of both software and hard-wired interlock logics. Plant monitoring and control are performed by efficient data communication through CAMAC highways and Ethernet with TCP/IP protocols. Sequential control of plasma discharges is executed by a combination of a remodeled VME-bus system and a timing system. A real-time plasma control system and a human interface system have been continuously modified corresponding to the progress of JT-60U experiments.

Yonekawa, I.; Kawamata, Y.; Totsuka, T.; Akasaka, H.; Sueoka, M.; Kurihara, K.; Kimura, T. [Japan Atomic Energy Research Institute (Japan)

2002-09-15

2

Measurements with the KATRIN pre-spectrometer  

NASA Astrophysics Data System (ADS)

The objective of the KArlsruhe TRItium Neutrino experiment (KATRIN) is a direct measurement of the absolute mass of the electron (anti)neutrino by means of precise spectroscopy of the tritium ?-spectrum near its endpoint. The pre-spectrometer is part of the KATRIN reference set-up where it will work as a pre-filter for low energy ?-decay electrons that are inessential for the determination of the ?-mass. Since its delivery in autumn 2003 the pre-spectrometer has been the first major hardware component of KATRIN in operation at Forschungszentrum Karlsruhe (FZK). The vacuum measurements were successfully completed in early 2005. The main results are an outgassing rate for the stainless steel surface of the pre-spectrometer of 10 -12 mbar l/s cm 2 at room temperature and a final pressure below 10 -11 mbar. This corresponds to the specification of the main spectrometer. The amount of Non-Evaporable-Getter (NEG) strips needed can be restricted to about 3000 m and the additional cooling of the main spectrometer is optional, if a combined pumping system of NEG and turbo-molecular pumps (TMPs) is installed, that will provide a sufficient pumping speed. The modification of the pre-spectrometer set-up for the electromagnetic measurements is nearly completed, and the measurements will start in spring 2006.

Bornschein, L.; For The Katrin Collaboration

2006-07-01

3

Characterizing electron optics in the KATRIN experiment  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino (KATRIN) experiment is a tritium beta decay experiment designed to make a direct, model independent measurement of the electron neutrino mass. The experimental apparatus employs strong magnetic and electric fields in regions of ultra high (10-11 mbar) vacuum in order to obtain precise measurements of the electron resulting from tritium decay. A potential background in such a configuration is from electric breakdown due to Penning discharge, where a charged particle confined within a Penning trap (a potential well along a magnetic field line) ionizes residual gas molecules. Using simulation tools developed to locate potential Penning traps within a given magnet and electrode configuration, it is possible to characterize and eliminate or minimize this source of background. )

Corona, Thomas

2010-02-01

4

Characterization of the KATRIN Focal Plane Detector  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino (KATRIN) Experiment is a next generation tritium beta decay experiment designed to measure directly the electron neutrino mass with a sensitivity of 0.2 eV. In the experiment, electrons from tritium decay of a gaseous source are magnetically guided through analyzing solenoidal retarding electrostatic spectrometers and detected via a focal plane detector. The focal plane detector is a 90mm diameter, 500 micron thick monolithic silicon pin-diode array with 148 pixels. The diode contacts have a titanium nitride overlayer and are connected to preamplifiers via an array of spring-loaded pogo pins. This novel connection scheme minimizes backgrounds from radioactive materials near the detector, facilitates characterization and replacement of the detector wafer, but requires a unique mounting design. The force of the pins strains the silicon, possibly altering the detector properties and performance. Results on the mechanical, thermal and electrical performance of a prototype detector under stress from pogo pin readouts will be presented.

Bodine, Laura; Leber, Michelle; Myers, Allan; Tolich, Kazumi; Vandevender, Brent; Wall, Brandon

2008-10-01

5

The Cryogenic Pumping Section of the KATRIN Experiment  

Microsoft Academic Search

In order to determine the absolute scale of the neutrino mass with a sensitivity of 0.2 (90% Confidence Level), the Karlsruhe Tritium Neutrino experiment (KATRIN) operates a series of superconducting magnet systems, which guide the electrons adiabatically from the source of tritium beta-decay to the detector within a magnetic flux of 191 . The 7 m long Cryogenic Pumping Section

Woosik Gil; Jochen Bonn; Beate Bornschein; Rainer Gehring; Oleg Kazachenko; Jonny Kleinfeller; Sergiy Putselyk

2010-01-01

6

Design, Research and Development of JT-60 Neutral Beam Injector.  

National Technical Information Service (NTIS)

JT-60 neutral beam injector (JT-60 NBI) injects neutral hydrogen beam into JT-60 with a maximum power of 20 MW/10 sec at an energy of 75 keV (70 - 100 keV), to achieve the break even plasma condition in JT-60. The performances required to JT-60 NBI were b...

M. Kuriyama M. Akiba N. Akino

1987-01-01

7

Precision high voltage divider for the KATRIN experiment  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the absolute mass of the electron antineutrino from a precise measurement of the tritium ?-spectrum near its endpoint at 18.6 keV with a sensitivity of 0.2 eV c-2. KATRIN uses an electrostatic retardation spectrometer of MAC-E filter type for which it is crucial to monitor high voltages of up to 35 kV with a precision and long-term stability at the ppm level. Since devices capable of this precision are not commercially available, a new high voltage divider for direct voltages of up to 35 kV has been designed, following the new concept of the standard divider for direct voltages of up to 100 kV developed at the Physikalisch-Technische Bundesanstalt (PTB)PTB is the German National Metrology Institute providing scientific and technical services.. The electrical and mechanical design of the divider, the screening procedure for the selection of the precision resistors, and the results of the investigation and calibration at the PTB are reported here. During the latter, uncertainties at the low ppm level have been deduced for the new divider, thus qualifying it for the precision measurements of the KATRIN experiment.

Thümmler, Th; Marx, R.; Weinheimer, Ch

2009-10-01

8

The thermal behaviour of the tritium source in KATRIN  

NASA Astrophysics Data System (ADS)

The tritium source in the Karlsruhe Tritium Neutrino Experiment (KATRIN) will deliver 1011 ? decay electrons per second, in order to determine the mass of the electron antineutrino through analysing the tritium ? spectrum. The source is built of a 10 m long beam tube of 90 mm inner diameter, which is operated at 30 K. Gaseous tritium is injected through a central injection chamber and diffuses towards the tube ends, where it is pumped by large turbomolecular pumps and further processed in a closed tritium loop. In order to achieve the KATRIN sensitivity of 0.2 eV/c2, the decay rate in the source (and hence the tritium density profile) must be stable to a level of ±0.1%. As the density profile is influenced by the beam tube conductance, both the temperature stability and the temperature homogeneity must be within a range of ±0.03 K at 30 K. A thermosiphon with saturated neon was developed for this purpose, with horizontal evaporator tubes connected all along the 10 m beam tube. The system behaviour was tested in a 12 m long test cryostat, containing the original beam tube with the adjacent pumping chambers, as well as the cooling circuits and the thermal shields. The so-called "Demonstrator" was operated in the Tritium Laboratory Karlsruhe (TLK) being connected to the cryogenic infrastructure of KATRIN. The temperature stability was found a factor 20 better than specified, achieving a standard deviation of only 1.5 mK/h, which corresponds to ?T/T = 5 × 10-5 h-1 relative stability at 30 K. The ±0.03 K temperature homogeneity along the 10 m beam tube was not yet reached, because of an increased heat load through the pump ports. The repeatability of the temperature measurement with vapour pressure sensors was within ± 0.004 K.

Grohmann, S.; Bode, T.; Hötzel, M.; Schön, H.; Süßer, M.; Wahl, T.

2013-05-01

9

JT8D engine performance retention  

NASA Technical Reports Server (NTRS)

The attractive performance retention characteristics of the JT8D engine are described. Because of its moderate bypass ratio and turbine temperature, and stiff structural design, the performance retention versus flight cycles of the JT8D engine sets a standard that is difficult for other engines to equal. In addition, the significant benefits of refurbishment of the JT8D engine are presented. Cold section refurbishment offers thrust specific fuel consumption improvements of up to 2 percent and payback in less than a year, making a very attractive investment option for the airlines.

James, A. D.; Weisel, D. R.

1981-01-01

10

Small refrigerated J-T plants  

SciTech Connect

The economic justification for building smaller natural gas liquids recovery plants has become a reality with the deregulated and decontrolled prices of gas liquids. Use of a Joule-Thomson (J-T) expansion valve to expand and cool compressed gas is discussed. Aspects of the process design, major equipment, instrumentation and electrification, field work, and approximate cost of J-T units are covered. The conclusion is that smaller modular designed cryogenic plants for natural gas liquids recovery are justified by use of a J-T expansion valve in lieu of a conventional expander unit.

Haws, R.

1981-01-01

11

Small refrigerated J-T plants  

Microsoft Academic Search

The economic justification for building smaller natural gas liquids recovery plants has become a reality with the deregulated and decontrolled prices of gas liquids. Use of a Joule-Thomson (J-T) expansion valve to expand and cool compressed gas is discussed. Aspects of the process design, major equipment, instrumentation and electrification, field work, and approximate cost of J-T units are covered. The

Haws

1981-01-01

12

Progress of the JT-60SA project  

NASA Astrophysics Data System (ADS)

The JT-60SA project implemented by Japan and Europe is progressing on schedule towards the first plasma in March 2019. After careful R&D, procurements of the major components have entered their manufacturing stages. In parallel, disassembly of JT-60U has been completed on time, and the JT-60SA tokamak assembly is expected to start in January 2013. The JT-60SA device, a highly shaped large superconducting tokamak with a variety of plasma control actuators, has been designed in order to contribute to ITER and to complement ITER in all the major areas of fusion plasma development necessary to decide DEMO reactor construction. Detailed assessments and prediction studies of the JT-60SA plasma regimes have confirmed these capabilities: using ITER- and DEMO-relevant plasma regimes, heating conditions, and its sufficiently long discharge duration, JT-60SA enables studies on magnetohydrodynamic stability at high beta, heat/particle/momentum transport, high-energy ion physics, pedestal physics including edge localized mode control, and divertor physics. By integrating these studies, the project provides ‘simultaneous and steady-state sustainment of the key performance characteristics required for DEMO’ with integrated control scenario development.

Kamada, Y.; Barabaschi, P.; Ishida, S.; the JT-60SA Team; Research Plan Contributors, JT-60SA

2013-10-01

13

Wall conditioning in JT-60  

NASA Astrophysics Data System (ADS)

The vacuum vessel of JT-60 has a volume of 160 m 3 and a vacuum side surface of 2750 m 2 containing the surfaces of the first wall and many types of ports. The first wall is made of 20 ?m TiC coated molybdenum and Inconel 625, bolted to the inner surface of the vacuum vessel. The vacuum vessel is evacuated with four identical pumping systems with a total pumping speed of 29 m 3/s for hydrogen. The wall conditioning procedure consisted of two wipes with special cloths wetted by freon after hot water and freon jet cleaning, and three bakeouts were carried out before the first plasma production. An ultimate pressure of 7.4 × 10 -7 Pa and an outgassing rate of 6.8 × 10 -10 Pa m 3/s m 2 were obtained. Low current pulse discharge cleaning (TDC) was carried out for two weeks at a vacuum vessel temperature of 200°C. The TDC is performed typically with a plasma current of 30 kA, a pulse duration of 40 ms, a repetition period in the range from 0.3 s to 1.2 s, a hydrogen pressure of 5.0 × 10 -3 Pa, and a toroidal field of 0.45 T. The TDC conditioning for 50 h removed a quantity of water vapor corresponding to approximately 0.3 g. The main residual gases consisting of hydrocarbons, were monitored in addition to hydrogen and carbon monoxide.

Arai, T.; Yamamoto, M.; Akino, N.; Kodama, K.; Nakamura, H.; Niikura, S.; Takatsu, H.; Shimizu, M.; Ohkubo, M.; Ohta, M.; JT-60 Team

1987-02-01

14

Status and commissioning of the Karlsruhe tritium neutrino experiment KATRIN  

NASA Astrophysics Data System (ADS)

Neutrino properties, and especially the determination of the neutrino rest mass, play an important role at the intersections of cosmology, particle physics and astroparticle physics. At present there are two complementary approaches to address this topic in laboratory experiments. The search for neutrinoless double ? decay probes whether neutrinos are Majorana particles and determines an effective neutrino mass value. Experiments based on single ? decay investigate electrons close to their kinematic endpoint in order to determine the neutrino mass by a modelindependent method. The KArlsruhe TRItium Neutrino experiment (KATRIN) is currently the experiment in the most advanced status of commissioning. Applying an ultra-luminous molecular windowless gaseous tritium source and an integrating high-resolution spectrometer of MAC-E filter type, it allows ? spectroscopy close to the tritium endpoint with unprecedented precision and will reach a sensitivity of 200 meV/c2 (90% C.L.) on the neutrino mass.

Thuemmler, Thomas; KATRIN Collaboration

2013-10-01

15

Commissioning of the Cryogenic Transfer Line for the Katrin Experiment  

NASA Astrophysics Data System (ADS)

The cryogenic transfer line for KATRIN connects 3 large superconducting magnet systems in the Tritium Laboratory Karlsruhe (TLK) with a He refrigerator installed in an external machine building. The vacuum-insulated transfer line comprises 1 N2 and 5 He process lines that are surrounded by a LN2-cooled radiation shield. Covering a distance of 40 m, the transfer line includes 4 valve boxes, 1 T-junction, 1 vertical and 3 horizontal line sections. After the introductory system description, an overview is given on project coordination and quality assurance, together with results of leak testing during pre-acceptance and commissioning. The method and results of thermal loss measurements in the He system are explained, reaching an accuracy of +/-30% with standard process instrumentation. Potential improvements in the MLI insulation scheme are revealed, based on both the measurements and theoretical considerations. The experimental results are finally compared with data of large cryogenic transfer systems.

Grohmann, S.; Gil, W.; Neumann, H.; Weiss, C.

2010-04-01

16

Present Status of JT-60SA Project and Development of Heating Systems for JT-60SA  

NASA Astrophysics Data System (ADS)

Present status of the JT-60SA (JT-60 Super Advanced) project, implemented jointly by Europe and Japan since 2007, is described. The design of the main tokamak components was completed in late 2008, and all the scientific missions are preserved to contribute to ITER and DEMO reactors. The construction of the JT-60SA has begun with procurement activities for the superconducting magnet systems, vacuum vessel, in-vessel components and other components under the relevant procurement arrangements between the implementing agencies of JAEA (Japan Atomic Energy Agency) in Japan and Fusion for Energy in Europe. Designs and developments of the auxiliary heating systems for JT-60SA have been progressing at JAEA so as to provide the total injection power of 41 MW for 100 s.

Yoshitaka, Ikeda; JT-60SA Team

2011-06-01

17

The JT8D and JT9D engine component improvement: Performance improvement program  

NASA Technical Reports Server (NTRS)

The NASA sponsored Engine Component Improvement - Performance Improvement Program at Pratt & Whitney Aircraft advanced the state of the art of thermal barrier coatings and ceramic seal systems, demonstrated the practicality of an advanced turbine clearance control system and an advanced fan design in the JT9D engine, and demonstrated the advantages of modern cooling, sealing, and aerodynamic designs in the high pressure turbine and compressor of the JT8D engine. Several of these improvements are already in airline service in JT8D and JT9D engines, and others will enter service soon in advanced models of these engines. In addition, the technology advances are being transferred to completely new engine configurations, the PW2037 engine and the NASA sponsored Energy Efficient Engine.

Gaffin, W. O.

1982-01-01

18

Gas and Pellet Injection Systems for JT-60 and JT-60U  

Microsoft Academic Search

Designs and operations of the gas system and pellet injection systems for JT-60 and JT-60U are described. A gas injection valve that is a key component of the gas injection system was developed using a multilayer piezoelectric element. The maximum flow rate of this system is 43.3 Pa.m³\\/s. The valve has mechanism for adjustment at atmospheric side meaning that a

K. Kizu; H. Hiratsuka; Y. Miyo; H. Ichige; T. Sasajima; T. Nishiyama; K. Masaki; M. Honda; N. Miya; N. Hosogane

2002-01-01

19

Design of JT-60U ICRF launcher.  

National Technical Information Service (NTIS)

JT-60U ICRF launcher is designed based on the measurement of electromagnetic field profile in front of a test launcher and the calculation of coupling properties. The coupling code was made for the antenna array whose each antenna element was recessed in ...

M. Saigusa H. Kimura T. Fujii N. Kobayashi S. Moriyama

1989-01-01

20

A broad-band FT-ICR Penning trap system for KATRIN  

NASA Astrophysics Data System (ADS)

The KArlsruhe TRItium Neutrino experiment KATRIN aims at improving the upper limit of the mass of the electron antineutrino to about 0.2 eV (90% c.l.) by investigating the -decay of tritium gas molecules . The experiment is currently under construction to start first data taking in 2012. One source of systematic uncertainties in the KATRIN experiment is the formation of ion clusters when tritium decays and decay products interact with residual tritium molecules. It is essential to monitor the abundances of these clusters since they have different final state energies than tritium ions. For this purpose, a prototype of a cylindrical Penning trap has been constructed and tested at the Max-Planck-Institute for Nuclear Physics in Heidelberg, which will be installed in the KATRIN beam line. This system employs the technique of Fourier-Transform Ion-Cyclotron-Resonance in order to measure the abundances of the different stored ion species.

Ubieto-Díaz, M.; Rodríguez, D.; Lukic, S.; Nagy, Sz; Stahl, S.; Blaum, K.

2009-12-01

21

A fast cool-down J-T minicryocooler  

Microsoft Academic Search

Design criteria for miniature open cycle Joule-Thomson (J-T) refrigerators were discussed by Geist and Lashmet (1960). Advantages of J-T minicryocoolers are related to compactness, low cost, and the ability to provide low temperatures very rapidly. Disadvantages include low efficiency and the requirement of a high-pressure gas source. The present investigation is concerned with a J-T minicryocooler which makes it possible

J. K. Xie

1984-01-01

22

An Overview of the Data Acquisition System in the KATRIN Experiment  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino (KATRIN) Experiment is a next generation tritium ?-decay experiment designed to make a model-independent measurement of the ?e-mass with an estimated sensitivity of 0.2 eV/c^2. This would represent an order of magnitude improvement in the ?e-mass sensitivity compared to previous tritium beta-decay experiments. The basic function of the Data Acquisition System (DAQ) is to process and store signals from all detector modules within the KATRIN experimental setup. In order to reach the specified ?e-mass sensitivity, the KATRIN DAQ must be able to process event rates over a range spanning a few mHz for ?e-mass measurements to MHz for calibration measurements. A multi-user graphical Object-oriented Real-time Control and Acquisition (ORCA) interface serves as the software that is employed to readout the DAQ electronics. In this talk, the KATRIN DAQ electronics as well as the ORCA software interface will be discussed. )

Phillips, David, II

2010-02-01

23

The Cryogenic Pumping Section of KATRIN and the Test Experiment TRAP  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino experiment (KATRIN) employs a Cryogenic Pumping Section (CPS) at ? 4.5 K to suppress the tritium penetration into the spectrometers. A test experiment (TRAP - Tritium Argon frost Pump) has been set up to investigate the tritium pumping performance of the CPS.

Eichelhardt, F.; Katrin Collaboration

2011-12-01

24

JT8D and JT9D jet engine performance improvement program. Task 1: Feasibility analysis  

NASA Technical Reports Server (NTRS)

JT8D and JT9D component performance improvement concepts which have a high probability of incorporation into production engines were identified and ranked. An evaluation method based on airline payback period was developed for the purpose of identifying the most promising concepts. The method used available test data and analytical models along with conceptual/preliminary designs to predict the performance improvements, weight, installation characteristics, cost for new production and retrofit, maintenance cost, and qualitative characteristics of candidate concepts. These results were used to arrive at the concept payback period, which is the time required for an airline to recover the investment cost of concept implementation.

Gaffin, W. O.; Webb, D. E.

1979-01-01

25

Measurement and reduction of low-level radon background in the KATRIN experiment  

SciTech Connect

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a next generation, model independent, large scale experiment to determine the mass of the electron anti-neutrino by investigating the kinematics of tritium beta decay with a sensitivity of 200 meV/c{sup 2}. The measurement setup consists of a high luminosity windowless gaseous molecular tritium source (WGTS), a differential and cryogenic pumped electron transport and tritium retention section, a tandem spectrometer section (pre-spectrometer and main spectrometer) for energy analysis, followed by a detector system for counting transmitted beta decay electrons. Measurements performed at the KATRIN pre-spectrometer test setup showed that the decay of radon (Rn) atoms in the volume of the KATRIN spectrometers is a major background source. Rn atoms from low-level radon emanation of materials inside the vacuum region of the KATRIN spectrometers are able to penetrate deep into the magnetic flux tube so that the alpha decay of Rn contributes to the background. Of particular importance are electrons emitted in processes accompanying the Rn alpha decay, such as shake-off, internal conversion of excited levels in the Rn daughter atoms and Auger electrons. Lowenergy electrons (< 100 eV) directly contribute to the background in the signal region. High-energy electrons can be stored magnetically inside the volume of the spectrometer and are able to create thousands of secondary electrons via subsequent ionization processes with residual gas molecules. In order to reduce the Rn induced background different active and passive counter measures were developed and tested. This proceeding will give an overview on Rn sources within the KATRIN spectrometer, describes how Rn decays inside the spectrometer produce background events at the detector and presents different counter measures to reduce the Rn induced background.

Fränkle, F. M. [F.M. Fränkle Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC (United States)] [F.M. Fränkle Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC (United States)

2013-08-08

26

Gas and Pellet Injection Systems for JT-60 and JT-60U  

SciTech Connect

Designs and operations of the gas system and pellet injection systems for JT-60 and JT-60U are described. A gas injection valve that is a key component of the gas injection system was developed using a multilayer piezoelectric element. The maximum flow rate of this system is 43.3 Pa.m{sup 3}/s. The valve has mechanism for adjustment at atmospheric side meaning that a repair and an adjustment can be conducted without ventilation inside a vacuum vessel. It was confirmed that the effect of magnetic field and temperature change on the valves in the JT-60U environment was negligible.In JT-60U, two systems of pellet injector - a pneumatic drive and a centrifugal one - were developed. The pneumatic type attained a pellet velocity of 2.3 km/s, which was the world record at the time in 1988. On the other hand, the centrifugal one was developed in 1998. This injector can eject trains of up to 40 cubic (2.1 mm{sup 3}) pellets at frequencies of 1 to 10 Hz and speed of 0.1 to 1.0 km/s. A guide tube for a magnetic high field side injection (HFS) (top) was also developed in 1999. The pellet injection experiment with the HFS system started in 2000. In addition, another guide tube for HFS(mid) injection was newly developed and installed in March 2001. These systems are working well.

Kizu, K.; Hiratsuka, H.; Miyo, Y.; Ichige, H.; Sasajima, T.; Nishiyama, T.; Masaki, K.; Honda, M.; Miya, N.; Hosogane, N. [Japan Atomic Energy Research Institute (Japan)

2002-09-15

27

Recent RF activities on JT-60U  

SciTech Connect

Recently, the JT-60U has employed ECRF system in addition to LHCD and ICRF systems. Three types of RF experiments on JT-60U have been performed. A reversed magnetic shear (R/S) configuration with internal transport barrier (ITB) was successfully maintained for 4.7 s in a quasi-steady state by LHCD in addition to the bootstrap current, where all profiles of temperature and plasma current were almost stationary. On the normal operation without heating during plasma current ramp-up, high electron temperature (T{sub e0}{approx}10 keV) with a strongly peaked profile was produced by LHCD alone at the density of {approx}0.5x10{sup 19} m{sup -3}. This peaked temperature profile was featured by a reduction in core density. The central electron temperature and density slowly changed in several seconds. The performances of ICRF (2{omega}{sub CH}) on the R/S configuration were also studied. Degradation of confinement of energetic particles was observed probably due to the large banana orbit loss. An 110 GHz ECRF system has been operated on JT-60U. Its gyrotron has successfully generated power at the level of up to 830 kW for 300 ms and is under conditioning. On the initial operation, the power of 620 kW was injected into plasmas. The central electron temperature increased from 3 keV to 5.5 keV at n{sub e}{approx}0.6x10{sup 19} m{sup -3}. A controllability of local heating was also demonstrated by the poloidally steerable mirror.

Ikeda, Y.; Fujita, T.; Hamamatus, K.; Ide, S.; Imai, T.; Isayama, A.; Iwase, M.; Kasugai, A.; Kondoh, T.; Kusama, Y.; Moriyama, S.; Naito, O.; Nemoto, M.; Oikawa, T.; Sakamoto, K.; Seki, M.; Shinozaki, S.; Simono, M.; Takahashi, T.; Terakado, M. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment Mukoyama 801-1, Naka-machi, Naka-gun, Ibaraki-ken, 311-0193 (Japan)] (and others)

1999-09-20

28

Throughput Calibration Methods for Piezoelectric Valves of JT-60.  

National Technical Information Service (NTIS)

In this report, we show the results concerning throughput calibration methods for piezoelectric valves (PEV) attached to the JT-60 vacuum vessel. We examine the methods by both experimental and numerical procedure. Main results are as follows. (1) We get ...

T. Horie K. Kawasaki H. Hiratsuka N. Yasumitsu

1984-01-01

29

Structural analysis of the JT-60SA cryostat base  

Microsoft Academic Search

Design and manufacturing of the JT-60SA cryostat is being performed by CIEMAT, according to the Broader Approach Agreement between Japan and the European Commission. Taking into account both the limitations of transport and the assembly sequence of JT60-SA, the cryostat is divided in two main parts, namely the cryostat base and the cryostat vessel body.The paper is focused on the

Esther Rincón; Javier Alonso; Germán Barrera; José Botija; Pilar Fernández; Mercedes Medrano; Germán Pérez; Francisco Ramos; Alfonso Soleto; Pietro Barabaschi; Enrico Di Pietro; Lionel Meunier; Akira Sakasai; Kei Masaki; Yusuke Shibama

2011-01-01

30

Operation and Development on the Positive-Ion Based Neutral Beam Injection System for JT-60 and JT-60U  

SciTech Connect

The positive-ion based neutral beam injection (NBI) system for JT-60, which consists of 14 beamline units and has a beam energy of 70 to 100 keV, started operation in 1986 with hydrogen beams and injected a neutral beam power of 27 MW at 75 keV into the JT-60 plasma. In 1991, the NBI system was modified to be able to handle deuterium beams as part of the JT-60 upgrade modification. After executing some research and developments, deuterium beams of 40 MW at 95 keV were injected in 1996. As a result, NBI has contributed to the achievement of the highest performance plasmas, a DT-equivalent fusion power gain of 1.25 and a fusion triple product of 1.55 x 10{sup 21} keVs/m{sup 3}, in the world on JT-60U.

Kuriyama, M. [Japan Atomic Energy Research Institute (Japan); Akino, N. [Japan Atomic Energy Research Institute (Japan); Ebisawa, N. [Japan Atomic Energy Research Institute (Japan); Honda, A. [Japan Atomic Energy Research Institute (Japan); Itoh, T. [Japan Atomic Energy Research Institute (Japan); Kawai, M. [Japan Atomic Energy Research Institute (Japan); Mogaki, K. [Japan Atomic Energy Research Institute (Japan); Ohga, T. [Japan Atomic Energy Research Institute (Japan); Oohara, H. [Japan Atomic Energy Research Institute (Japan); Umeda, N. [Japan Atomic Energy Research Institute (Japan); Usui, K. [Japan Atomic Energy Research Institute (Japan); Yamamoto, M. [Japan Atomic Energy Research Institute (Japan); Yamamoto, T. [Japan Atomic Energy Research Institute (Japan); Matsuoka, M. [University of Mie (Japan)

2002-09-15

31

JT15D simulated flight data evaluation  

NASA Technical Reports Server (NTRS)

The noise characteristics of the JT15D turbofan engine was analyzed with the objectives of: (1) assessing the state-of-art ability to simulate flight acoustic data using test results acquired in wind tunnel and outdoor (turbulence controlled) environments; and (2) predicting the farfield noise directivity of the blade passage frequency (BPF) tonal components using results from rotor blade mounted dynamic pressure instrumentation. Engine rotor tip speeds at subsonic, transonic, and supersonic conditions were evaluated. The ability to simulate flight results was generally within 2-3 dB for both outdoor and wind tunnel acoustic results. Some differences did occur in the broadband noise level and in the multiple-pure-tone harmonics at supersonic tip speeds. The prediction of blade passage frequency tone directivity from dynamic pressure measurements was accomplished for the three tip speed conditions. Predictions were made of the random and periodic components of the tone directivity. The technique for estimating the random tone component used hot wire data to establish a correlation between dynamic pressure and turbulence intensity. This prediction overestimated the tone level by typically 10 dB with the greatest overestimates occurring at supersonic conditions.

Holm, R. G.

1984-01-01

32

The JT-60SA Cryoplant Current Design Status  

NASA Astrophysics Data System (ADS)

In the framework of the ITER Broader Approach, CEA is carrying out the procurement of the Cryogenic System to the JA-EU Satellite Tokamak JT-60SA, which should be operated in Japan at JAEA, Naka in 2014. According to the Conceptual Design Report, JT-60SA is to operate for periods of at least 6 months per year, with major shutdown periods in between for maintenance and further installation upgrades. For this operation scenario, the cryoplant and the cryodistribution have to cope with different heat loads which depend on the different JT-60SA operating states. The cryoplant consists of one 4.5 K refrigerator and one 80 K helium loop, each pre-cooled by LN2. These cryogenic subsystems have to operate simultaneously in order to remove the heat loads from the superconducting magnets, 80 K shields and the divertor cryopumps. The first part of this study is based on the Process Flow Diagram (PFD) and presents the current design status of the JT-60SA cryogenic system. The second part is dedicated to the analysis of the cryoplant normal operation modes including the regeneration mode of the divertor cryopumps. Thanks to this analysis, the architecture of the present PFD is proposed in order to match the technical specifications of the cryoplant with the JT-60SA operation requirements.

Henry, D.; Michel, F.; Roussel, P.; Reynaud, P.; Journeaux, J. Y.; Maréchal, J. L.; Balaguer, D.; Roux, C.; Matsukawa, M.; Yoshida, K.

2008-03-01

33

Dynamic design of gas sorption J-T refrigerator  

NASA Technical Reports Server (NTRS)

A long-life Joule-Thomson refrigerator which is heat powered, involves no sealing, and has few mechanical parts is desirable for long-term sensor cooling in space. In the gas-sorption J-T refrigerator, cooling is achieved by gas sorption (either adsorption or absorption) processes. Currently, a modular, single-stage refrigerator is being designed and built to be operated at 20 K. The design was analyzed using a dynamic model, which is described here. The model includes the kinetics of the compressors and the heat switches, the heat transfer of the pre-coolers and the heat exchangers, the on/off ratio of the check valves, and the impedance of the J-T valve. The cooling power, the cycle time, and the operating conditions were obtained in terms of the power input, the heat sink temperature, and the J-T impedance.

Chan, C. K.

1986-01-01

34

A fast cool-down J-T minicryocooler  

NASA Astrophysics Data System (ADS)

Design criteria for miniature open cycle Joule-Thomson (J-T) refrigerators were discussed by Geist and Lashmet (1960). Advantages of J-T minicryocoolers are related to compactness, low cost, and the ability to provide low temperatures very rapidly. Disadvantages include low efficiency and the requirement of a high-pressure gas source. The present investigation is concerned with a J-T minicryocooler which makes it possible to reach low temperatures very rapidly. The considered device has special design features, including a two-phase valve, a directly-wound fin tube, and a special combination of three heat exchangers. Attention is given to the thermodynamic cycle, a new heat exchanger for improving the capacity of minicryocoolers, and test data.

Xie, J. K.

35

Development of integrated SOL/divertor code and simulation study of the JT-60U/JT-60SA tokamaks  

NASA Astrophysics Data System (ADS)

To predict the heat and particle controllability in the divertor of tokamak reactors and to optimize the divertor design, comprehensive simulations by integrated modeling allowing for various physical processes are indispensable. SOL/divertor codes have been developed in the Japan Atomic Energy Agency for the interpretation and the prediction of behaviour of SOL/divertor plasmas, neutrals and impurities. The code system consists of the two-dimensional fluid code SOLDOR, the neutral Monte-Carlo (MC) code NEUT2D and the impurity MC code IMPMC. Their integration code 'SONIC' is almost completed and examined to simulate self-consistently the SOL/divertor plasmas in JT-60U. In order to establish the physics modelling used in fluid simulations, the particle simulation code PARASOL has also been developed. Simulation studies using those codes have progressed with the analysis of JT-60U experiments and the divertor designing of JT-60SA (modification program of JT-60U). The X-point multifaceted asymmetric radiation from the edge in the JT-60U experiment is simulated. It is found that the deep penetration of chemically sputtered carbon at the dome causes the large radiation peaking near the X-point. The pumping capability of JT-60SA is evaluated through the simulation. A guideline to enhance the pumping efficiency is obtained in terms of the exhaust slot width and the strike point distance. Transient behaviour of SOL/divertor plasmas after an ELM crash is characterized by the PARASOL simulation; the fast-time-scale heat transport is affected by collisions while the slow-time-scale behaviour is affected by the recycling.

Kawashima, H.; Shimizu, K.; Takizuka, T.

2007-07-01

36

Alfvén eigenmode and energetic particle research in JT-60U  

Microsoft Academic Search

Recent results on investigations of Alfvén eigenmodes, fast ion confinement and fast ion diagnostics in JT-60U are presented. It was found that toroidicity induced Alfvén eigenmodes (TAEs) were stable in negative shear discharges with a large density gradient at the internal transport barrier (ITB). If the density gradient was small at the ITB, multiple TAEs appeared around the q =

H. Kimura; Y. Kusama; M. Saigusa; G. J. Kramer; K. Tobita; M. Nemoto; T. Kondoh; T. Nishitani; O. Da Costa; T. Ozeki; T. Oikawa; S. Moriyama; A. Morioka; G. Y. Fu; C. Z. Cheng; V. I. Afanas'ev

1998-01-01

37

JT-60SA TF Coil Testing Cooling Prevision  

Microsoft Academic Search

The JT-60SA Toroidal Field coil design has been modified resulting in considerable material savings. The casing cooling loop is important during the beginning of cooldown. This study models the cooling phase foreseen for coil testing and coil operation. Data and experience gathered during the extensive cooling tests performed on 70 large W7-X coils at the CEA (Saclay) cryomagnetic test facility

Bertrand Renard; Laurent Genini; Jean-Luc Duchateau

2010-01-01

38

JT8D High Pressure Compressor Performance Improvement.  

National Technical Information Service (NTIS)

An improved performance high pressure compressor with potential application to all models of the JT8D engine was designed. The concept consisted of a trenched abradable rubstrip which mates with the blade tips for each of the even rotor stages. This featu...

W. O. Gaffin

1981-01-01

39

Negative ion based neutral beam injector for JT-60U  

SciTech Connect

A 500 keV, 10 MW neutral beam injector is to be constructed in JT-60 Upgrade for the experiments of current drive and heating of heat density core plasmas. This is the first neutral beam injector in the world using negative ions as the primary ions. In the design, D[sup [minus

Okumura, Y.; Araki, M.; Hanada, M.; Inoue, T.; Kunieda, S.; Kuriyama, M.; Matsuoka, M.; Mizuno, M.; Ohara, Y.; Tanaka, M.; Watanabe, K. (Japan Atomic Energy Research Institute, Naka-machi, Naga-gun, Ibaraki-ken, 311-01 (Japan))

1992-10-05

40

Development of JT-60SA superconducting magnet system  

NASA Astrophysics Data System (ADS)

The upgrade of JT-60U magnet system to superconducting coils (JT-60SA) is progressing by both parties of Japanese government and European commission in the framework of the Broader Approach agreement. The magnet system for JT-60SA consists of 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with four modules, six Equilibrium Field (EF) coils. The TF coil case encloses the winding pack and is the main structural component of the magnet system. The CS consists of four independent winding pack modules, which is support from the bottom of the TF coils. The six EF coils are attached to the TF coil cases through supports with flexible plates allowing radial displacements. The construction of CS and EF coils was started in 2008 by Japan Atomic Energy Agency (JAEA). The construction of TF coils will be started in 2009 by Fusion for Energy and European voluntary contributors. This paper introduces the design of the JT-60SA superconducting magnet system and activities for development of magnet components in Japan.

Yoshida, K.; Tsuchiya, K.; Kizu, K.; Murakami, H.; Kamiya, K.; Obana, T.; Takahata, K.; Peyrot, M.; Barabaschi, P.

2010-11-01

41

Comparison of boronized wall in LHD and JT-60U  

Microsoft Academic Search

Boronization has been performed in many fusion plasma devices as one of several effective wall conditioning techniques. In LHD and JT-60U, boronization is operated as a typical wall conditioning method. Using material probes stayed in LHD during an experimental campaign, characteristics of a boronized wall are discussed in each device. Due to the complex three dimensional structure of the vacuum

N. Ashikawa; K. Kizu; J. Yagyu; T. Nakahata; Y. Nobuta; K. Nishimura; A. Yoshikawa; Y. Ishimoto; Y. Oya; K. Okuno; N. Miya; T. Hino; S. Masuzaki; A. Sagara; N. Ohyabu; LHD Experimental Groupa

2007-01-01

42

Upgrade of JT-60 Pellet Injector for Higher Velocity.  

National Technical Information Service (NTIS)

Pellet injection experiments have been performed to improve the plasma performance by the JT-60 tokamak from June, 1988. From the results of the experiments, it was found that the plasma confinement time increased up to 40% with pellet injection (velocity...

H. Hiratsuka Y. Miyo Y. Yoshioka K. Ohta M. Shimizu

1989-01-01

43

Development of the Piezoelectric Gas Injection Valve for JT-60.  

National Technical Information Service (NTIS)

Piezoelectric gas injection valve (PEV) for JT-60 have been developed which was a piezo-electric element. The raliability of the PEV under the actual condition of high magnetic fields and high temperatures are veryfied, and it became clear that the PEV ha...

1986-01-01

44

Development of Laminated Piezoelectric Gas Injection Valve for JT-60.  

National Technical Information Service (NTIS)

Gas injection valves of ''lift'' and ''lever'' types for JT-60 have been developed with laminated piezoelectric elements. The valves of the two types are remarked as follows: (1) The respective response time and helium leakage rate satisfy the designed sp...

H. Hiratsuka K. Kawasaki Y. Miyo T. Kuroda K. Ohta

1988-01-01

45

Simulation of background from low-level tritium and radon emanation in the KATRIN spectrometers  

SciTech Connect

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a large-scale experiment for the model independent determination of the mass of electron anti-neutrinos with a sensitivity of 200 meV/c{sup 2}. It investigates the kinematics of electrons from tritium beta decay close to the endpoint of the energy spectrum at 18.6 keV. To achieve a good signal to background ratio at the endpoint, a low background rate below 10{sup ?2} counts per second is required. The KATRIN setup thus consists of a high luminosity windowless gaseous tritium source (WGTS), a magnetic electron transport system with differential and cryogenic pumping for tritium retention, and electro-static retarding spectrometers (pre-spectrometer and main spectrometer) for energy analysis, followed by a segmented detector system for counting transmitted beta-electrons. A major source of background comes from magnetically trapped electrons in the main spectrometer (vacuum vessel: 1240 m{sup 3}, 10{sup ?11} mbar) produced by nuclear decays in the magnetic flux tube of the spectrometer. Major contributions are expected from short-lived radon isotopes and tritium. Primary electrons, originating from these decays, can be trapped for hours, until having lost almost all their energy through inelastic scattering on residual gas particles. Depending on the initial energy of the primary electron, up to hundreds of low energetic secondary electrons can be produced. Leaving the spectrometer, these electrons will contribute to the background rate. This contribution describes results from simulations for the various background sources. Decays of {sup 219}Rn, emanating from the main vacuum pump, and tritium from the WGTS that reaches the spectrometers are expected to account for most of the background. As a result of the radon alpha decay, electrons are emitted through various processes, such as shake-off, internal conversion and the Auger deexcitations. The corresponding simulations were done using the KASSIOPEIA framework, which has been developed for the KATRIN experiment for low-energy electron tracking, field calculation and detector simulation. The results of the simulations have been used to optimize the design parameters of the vacuum system with regard to radon emanation and tritium pumping, in order to reach the stringent requirements of the neutrino mass measurement.

Leiber, B. [Institute for Nuclear Physics (IKP), Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany)] [Institute for Nuclear Physics (IKP), Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany); Collaboration: KATRIN Collaboration

2013-08-08

46

Simulation of background from low-level tritium and radon emanation in the KATRIN spectrometers  

NASA Astrophysics Data System (ADS)

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a large-scale experiment for the model independent determination of the mass of electron anti-neutrinos with a sensitivity of 200 meV/c2. It investigates the kinematics of electrons from tritium beta decay close to the endpoint of the energy spectrum at 18.6 keV. To achieve a good signal to background ratio at the endpoint, a low background rate below 10-2 counts per second is required. The KATRIN setup thus consists of a high luminosity windowless gaseous tritium source (WGTS), a magnetic electron transport system with differential and cryogenic pumping for tritium retention, and electro-static retarding spectrometers (pre-spectrometer and main spectrometer) for energy analysis, followed by a segmented detector system for counting transmitted beta-electrons. A major source of background comes from magnetically trapped electrons in the main spectrometer (vacuum vessel: 1240 m3, 10-11 mbar) produced by nuclear decays in the magnetic flux tube of the spectrometer. Major contributions are expected from short-lived radon isotopes and tritium. Primary electrons, originating from these decays, can be trapped for hours, until having lost almost all their energy through inelastic scattering on residual gas particles. Depending on the initial energy of the primary electron, up to hundreds of low energetic secondary electrons can be produced. Leaving the spectrometer, these electrons will contribute to the background rate. This contribution describes results from simulations for the various background sources. Decays of 219Rn, emanating from the main vacuum pump, and tritium from the WGTS that reaches the spectrometers are expected to account for most of the background. As a result of the radon alpha decay, electrons are emitted through various processes, such as shake-off, internal conversion and the Auger deexcitations. The corresponding simulations were done using the KASSIOPEIA framework, which has been developed for the KATRIN experiment for low-energy electron tracking, field calculation and detector simulation. The results of the simulations have been used to optimize the design parameters of the vacuum system with regard to radon emanation and tritium pumping, in order to reach the stringent requirements of the neutrino mass measurement.

Leiber, B.; KATRIN Collaboration

2013-08-01

47

Application of J-T plants for LP-gas recovery  

SciTech Connect

The paper describes the J-T (Joule-Thomson) process that consists of the adiabatic expansion of a gas through a choke or valve from a high pressure to a low pressure. Various applications of the J-T process in oil and gas production are discussed with emphasis on LPG recovery. It is shown that J-T plants offer an attractive alternative to the turboexpander and refrigeration processes for certain applications.

Crum, F.S.

1981-01-01

48

Application of J-T plants for LP-gas recovery  

Microsoft Academic Search

The paper describes the J-T (Joule-Thomson) process that consists of the adiabatic expansion of a gas through a choke or valve from a high pressure to a low pressure. Various applications of the J-T process in oil and gas production are discussed with emphasis on LPG recovery. It is shown that J-T plants offer an attractive alternative to the turboexpander

Crum

1981-01-01

49

MIXING STUDY FOR JT-71/72 TANKS  

SciTech Connect

All modeling calculations for the mixing operations of miscible fluids contained in HBLine tanks, JT-71/72, were performed by taking a three-dimensional Computational Fluid Dynamics (CFD) approach. The CFD modeling results were benchmarked against the literature results and the previous SRNL test results to validate the model. Final performance calculations were performed by using the validated model to quantify the mixing time for the HB-Line tanks. The mixing study results for the JT-71/72 tanks show that, for the cases modeled, the mixing time required for blending of the tank contents is no more than 35 minutes, which is well below 2.5 hours of recirculation pump operation. Therefore, the results demonstrate the adequacy of 2.5 hours’ mixing time of the tank contents by one recirculation pump to get well mixed.

Lee, S.

2013-11-26

50

The materials aspects of the JT-60 device  

NASA Astrophysics Data System (ADS)

JT-60 is the JAERI Tokamak, of which the objective is to achieve the break-even plasma condition making use of a hydrogen plasma. The construction of this device will be completed in the spring of 1985. The following seven items of JT-60 are discussed from the point of view of materials. (1) Vacuum vessel material: Inconel 625, (2) Liner plates as the first wall: Molybdenum and Inconel 625, (3) Fixed limiters, magnetic limiter plates and armor plates for neutral beam injection: Molybdenum, (4) Coating of the first wall: TiC, (5) In-situ coating of TiC within the torus, (6) Non-magnetic structural materials, and (7) Conductor materials for magnet coils.

Hasiguti, R. R.; Tomabechi, K.

1984-05-01

51

Results of acoustic testing of the JT8D-109 refan engines  

NASA Technical Reports Server (NTRS)

A JT8D engine was modified to reduce jet noise levels by 6-8 PNdB at takeoff power without increasing fan generated noise levels. Designated the JT8D-109, the modified engines featured a larger single stage fan, and acoustic treatment in the fan discharge ducts. Noise levels were measured on an outdoor test facility for eight engine/acoustic treatment configurations. Compared to the baseline JT8D, the fully treated JT8D-109 showed reductions of 6 PNdB at takeoff, and 11 PNdB at a typical approach power setting.

Burdsall, E. A.; Brochu, F. P.; Scaramella, V. M.

1975-01-01

52

The 727/JT8D refan side nacelle airloads  

NASA Technical Reports Server (NTRS)

Airloads on the 727/JT8D refan side engine nacelle are presented. These consist of surface static pressure distributions from two low speed wind tunnel tests. External nacelle surface pressures are from testing of a flow-through, body mounted nacelle model, and internal inlet surface pressures are from performance testing of a forced air inlet model. The method for obtaining critical airloads on nacelle components and a representative example are discussed.

Bailey, R. W.; Vadset, H. J.

1974-01-01

53

Extended JT-60U plasma regimes for high integrated performance  

Microsoft Academic Search

With the main aim of providing the physics basis for ITER and steady state tokamak reactors, JT-60U has been optimizing operational concepts and extending discharge regimes towards simultaneous sustainment of high confinement, high betaN, high bootstrap fraction, full non-inductive current drive, and efficient heat and particle exhaust utilizing a variety of heating, current drive, torque input and particle control capabilities.

Y. Kamada

2001-01-01

54

JT9D ceramic outer air seal system refinement program  

NASA Technical Reports Server (NTRS)

The abradability and durability characteristics of the plasma sprayed system were improved by refinement and optimization of the plasma spray process and the metal substrate design. The acceptability of the final seal system for engine testing was demonstrated by an extensive rig test program which included thermal shock tolerance, thermal gradient, thermal cycle, erosion, and abradability tests. An interim seal system design was also subjected to 2500 endurance test cycles in a JT9D-7 engine.

Gaffin, W. O.

1982-01-01

55

Dynamic design of gas sorption J-T refrigerator  

Microsoft Academic Search

A long-life Joule-Thomson refrigerator which is heat powered, involves no sealing, and has few mechanical parts is desirable for long-term sensor cooling in space. In the gas-sorption J-T refrigerator, cooling is achieved by gas sorption (either adsorption or absorption) processes. Currently, a modular, single-stage refrigerator is being designed and built to be operated at 20 K. The design was analyzed

C. K. Chan

1986-01-01

56

Particle simulation of bursting Alfven modes in JT-60U  

SciTech Connect

The results of particle-in-cell simulations of a negative neutral beam heated Alfven-mode experiment in the Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) [H. Ninomiya et al., Fusion Sci. Technol. 42, 7 (2002); A. Kitsunezaki et al., ibid. 42, 179 (2002)] are presented. They seem to match quite well the dynamics of the abrupt large-amplitude event (ALE) experimentally observed in the reference JT-60U discharge. The time scale and frequency spread of the ALE are well reproduced too. The issue of the weaker Alfven fluctuation phase following the ALEs, characterized by fast frequency sweeping modes, is also investigated and an interpretation of the full JT-60U bursting-mode phenomenology is presented. Finally, the simulation tool is exploited by ad hoc synthetic diagnostics on the fast ion distribution function to get a deeper insight into the ALE nonlinear dynamics. The underlying fast-growing energetic particle mode saturates as resonant energetic ions are scattered out of the resonance region and displaced outwards. The radially displaced ions resonate with outer Alfven modes and enhance their local drive, consistently with the ''avalanche'' paradigm for mode nonlinear dynamics and energetic ion transports.

Briguglio, S.; Fogaccia, G.; Vlad, G.; Zonca, F.; Shinohara, K.; Ishikawa, M.; Takechi, M. [Associazione EURATOM-ENEA, CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati (Rome) (Italy); Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

2007-05-15

57

Studies of MHD behaviour in JT-60U  

NASA Astrophysics Data System (ADS)

Several important topics relating to MHD behaviour in JT-60U are presented. An extremely hollow current profile was found for the first time in JT-60U with a very small plasma current in the central region, which is called the current hole. Analyses of equilibrium and stability of the current hole discharge show that, as betap increases, the Pfirsh-Schlüter current increases, which reduces the poloidal field on the inboard side. It may cause the null point of the magnetic field. beta limits due to ideal MHD instability in the current hole do not change very much compared to that of the weakly reversed shear plasma. In high beta long pulse plasmas, it is important to suppress the resistive MHD instability, neo-classical tearing mode (NTM), induced by the lack of bootstrap current inside the magnetic island. Analyses of two typical JT-60U discharges with and without NTM show that the polarization current due to the plasma rotation is a plausible candidate to suppress the NTM though it is very sensitive to the value of mode rotation. To establish an advanced control of NTM, a real-time control system, which can identify the island by ECE measurement and control EC ray to the island by a steerable mirror, was prepared in JT-60U, and it successfully stabilized the NTM. Instability due to fast ions is an important subject for sustaining the fusion reaction. In JT-60U, slow frequency sweeping (slow-FS) modes and bursting MHD modes in the frequency range of the toroidicity-induced Alfvén eigenmodes (TAEs) are observed by injections of negatively-charged ion based neutral beam of ~360 keV. Analyses by the HINST code show that the resonant TAE mode is a candidate of the slow-FS mode. A bursting mode was observed to change its frequency by 10-20 kHz in 1-5 ms (fast FS mode) and evolve explosively in ~400 mus (abrupt large amplitude event). Analyses of the bursting mode show that the non-linear deformation of the energetic ion distribution may cause the repetition of bursting phenomena and the recovery of lost energetic ions.

Ozeki, T.; JT-60 Team

2003-05-01

58

Improvement of JT-60U Negative Ion Source Performance  

SciTech Connect

The negative ion neutral beam system now operating on JT-60U was the first application of negative ion technology to the production of beams of high current and power for conversion to neutral beams, and has successfully demonstrated the feasibility of negative ion beam heating systems for ITER and future tokamak reactors [1, 2]. It also demonstrated significant electron heating[3] and high current drive efficiency in JT-60U[4]. Because this was such a large advance in the state of the art with respect to all system parameters, many new physical processes appeared during the earlier phases of the beam injection experiments. We have explored the physical mechanisms responsible for these processes, and implemented solutions for some of them, in particular excessive beam stripping, the secular dependence of the arc and beam parameters, and nonuniformity of the plasma illuminating the beam extraction grid. This has reduced the percentage of beam heat loading on the downstream grids by roug hly a third, and permitted longer beam pulses at higher powers. Progress is being made in improving the negative ion current density, and in coping with the sensitivity of the cesium in the ion sources to oxidation by tiny air or water leaks, and the cathode operation is being altered.

L.R. Grisham; M. Kuriyama; M. Kawai; T. Itoh; N. Umeda; JT-60U Team

2000-11-15

59

Electron 83Rb/83mKr Source for the Energy Scale Monitoring in the KATRIN Experiment  

NASA Astrophysics Data System (ADS)

The KATRIN (KArlsruhe TRItium Neutrino) experiment investigates the endpoint region of the tritium ?-spectrum aiming for the sensitivity on the neutrino mass of 0.2 eV (90% C.L.). A spectrometer of the MAC-E filter (Magnetic Adiabatic Collimation with an Electrostatic filter) type will be used for a total time of at least 5 years. An unrecognized shift of the filtering potential would directly influence the resulting neutrino mass. To continuously monitor the filtering potential the high voltage (HV) will be simultaneously applied to an additional MAC-E filter spectrometer. In this monitor spectrometer suitable electron sources based on atomic/nuclear standards will be utilized. As one of such monitoring tools the solid 83Rb/83mKr source is intended. It provides conversion electrons from 83mKr(t1/2 = 1.83 h) which is continuously generated by 83Rb(t1/2~=86 d). The Calibration and Monitoring task of the KATRIN project demands the long-term energy stability ?E/E of the K-32 conversion electron line (E = 17.8 keV, ? = 2.7 eV) of +/-1.6 ppm/month.

Zbo?il, Miroslav

2011-12-01

60

Engineering Problems of JT-60 First Wall under NBI Fast Neutral Particle Bombardment.  

National Technical Information Service (NTIS)

Engineering problems of the JT-60 first wall under NBI fast neutral particle bombardment have been investigated. A permissible delay time of the NBI shutdown at faulty conditions and restrictions to NBI experiments were revealed in mechanical strength of ...

H. Nakamura M. Kuriyama

1979-01-01

61

Mechanical and Thermal Characteristics of JT-60 Tokamak Machine Demonstrated in Its Power Tests.  

National Technical Information Service (NTIS)

JT-60 power tests were carried out from December 10, 1984 to February 20, 1985 to demonstrate, in advance of actual plasma operation, satisfactory performance of tokamak machine, power suppliers and control system in combination. The tests began with low ...

H. Takatsu M. Yamamoto M. Ohkubo

1985-01-01

62

Development of piezoelectric actuator gas injection valve for JT-60U.  

National Technical Information Service (NTIS)

Piezoelectric actuator gas injection valve by lever for JT-60U have been developed using piezoelectric actuator (Laminated piezoelectric elements). Specifications of the valve are summarized as follows: (1) The piezoelectric actuator gas injection valve b...

H. Hiratsuka Y. Miyo T. Koike M. Shimizu K. Komuro

1995-01-01

63

Two-phase coexistence analysis of the bellows control mechanism for a J-T cryocooler  

NASA Astrophysics Data System (ADS)

The bellows control mechanism is one of the most critical control elements in the Joule-Thomson cryocooler. In the cool-down process, the interior gas of the bellows may reach liquefaction temperature, cause vapour-liquid two phase coexistence phenomena, and achieve the quick open/close control function of a J-T valve. This paper establishes a transient model of a simplified bellows mechanism, investigates the variation of the state properties of nitrogen inside the bellows, and its effects on the performance with different bellows stiffness in the cool-down process. According to the real shape and dimension, the two-phase model is put into a J-T cryocooler integrated model to accomplish the J-T cryocooler system simulation. To adopt the benefit of two-phase coexistence behavior effectively, a revised initial J-T valve design is also proposed in this work.

Chien, S. B.; Chen, L. T.

1999-07-01

64

Miniature Joule Thomson (JT) CryoCoolers for Propellant Management  

NASA Technical Reports Server (NTRS)

A proof-of-concept project is proposed here that would attempt to demonstrate how miniature cryocoolers can be used to chill the vacuum jacket line of a propellant transfer line and thus to achieve transfer line pre-chill, zero boil off and possible propellant densification. The project would be performed both at UCF and KSC, with all of the cryogenic testing taking place in the KSC cryogenic test bed. A LN2 line available in that KSC test facility would serve to simulate a LOX transfer line. Under this project, miniature and highly efficient cold heads would be designed. Two identical cold heads will be fabricated and then integrated with a JT-type cryogenic system (consisting of a common compressor and a common external heat exchanger). The two cold heads will be integrated into the vacuum jacket of a LN2 line in the KSC cryo lab, where the testing will take place.

Kapat, Jay; Chow, Louis

2002-01-01

65

JT8D high pressure compressor performance improvement  

NASA Technical Reports Server (NTRS)

An improved performance high pressure compressor with potential application to all models of the JT8D engine was designed. The concept consisted of a trenched abradable rubstrip which mates with the blade tips for each of the even rotor stages. This feature allows tip clearances to be set so blade tips run at or near the optimum radius relative to the flowpath wall, without the danger of damaging the blades during transients and maneuvers. The improved compressor demonstrated thrust specific fuel consumption and exhaust gas temperature improvements of 1.0 percent and at least 10 C over the takeoff and climb power range at sea level static conditions, compared to a bill-of-material high pressure compressor. Surge margin also improved 4 percentage points over the high power operating range. A thrust specific fuel consumption improvement of 0.7 percent at typical cruise conditions was calculated based on the sea level test results.

Gaffin, W. O.

1981-01-01

66

Long Pulse Operation on NBI Systems for JT-60U  

SciTech Connect

In the neutral beam injection (NBI) system, an extension of the pulse duration up to 30 sec has been intended to study quasi-steady state plasma on JT-60U. The four positive-ion based (P-NBI) units, which tangentially inject neutral beam to plasma, were mainly modified on the electric power supplies and the beam limiters to extend the pulse duration up to 30 sec with 2 MW at 80 keV per each. The seven P-NBI units, each of which perpendicularly injects for 10 sec, were conducted to operate in series for the total pulse duration of 30 sec. The ion source of the negative-ion based (N-NBI) unit, whose target beam energy is 500 keV for 10 sec, was also modified to reduce the heat load of the grid for long pulse operation. The reduction of the re-ionization of the neutral beam in the beam drift duct was a key to achieve a long pulse injection. It was found that the pressure rise in the beam drift duct, which gives the re-ionization rate, depended on the temperature of the re-ionization plates during NBI injection. Up to now, it was attained successfully that the pulse duration of the tangential P-NBI unit was extended up to 30 sec. 310 MJ of the total integrated injection energy into JT-60U plasma was achieved, including the negative-ion based NBI operation for 17 sec at 366 keV.

Akino, N.; Ebisawa, N. [Japan Atomic Energy Resaerch Institute (Japan); Honda, A. [Japan Atomic Energy Resaerch Institute (Japan); Ikeda, Y. [Japan Atomic Energy Resaerch Institute (Japan); Kawai, M. [Japan Atomic Energy Resaerch Institute (Japan); Kazawa, M. [Japan Atomic Energy Resaerch Institute (Japan); Mogaki, K. [Japan Atomic Energy Resaerch Institute (Japan); Ohga, T. [Japan Atomic Energy Resaerch Institute (Japan); Umeda, N. [Japan Atomic Energy Resaerch Institute (Japan); Usui, K. [Japan Atomic Energy Resaerch Institute (Japan); Yamamoto, T. [Japan Atomic Energy Resaerch Institute (Japan); Grisham, L. [Princeton Plasma Physics Laboratory (United States)

2005-04-15

67

Operation of the negative-ion based NBI for JT-60U  

Microsoft Academic Search

A beam injection experiment with the negative-ion based NBI system (N-NBI) started in March 1996 on JT-60U. After achieving the first neutral beam injection of 180 keV, ?0.1 MW for 0.4 s into the JT-60U plasmas, the operation parameters of the ion source and power supply had been optimized for increasing the beam energy and beam current. In September 1996,

M. Kuriyama; N. Akino; T. Aoyagi; N. Ebisawa; N. Isozaki; A. Honda; T. Inoue; T. Itoh; M. Kawai; M. Kazawa; J. Koizumi; K. Mogaki; Y. Ohara; T. Ohga; Y. Okumura; H. Oohara; K. Ohshima; F. Satoh; T. Takenouchi; Y. Toyokawa; K. Usui; K. Watanabe; M. Yamamoto; T. Yamazaki; C. Zhou

1998-01-01

68

Absolute calibration of the JT-60U neutron monitors using a 252Cf neutron sourcea)  

Microsoft Academic Search

Absolutely calibrated measurements of the neutron yield are important for the evaluation of plasma performance such as the fusion gain Q in D–D operating tokamaks. The time-resolved neutron yield is measured with 235U and 238U fission chambers and 3He proportional counters in the JT-60U tokamak. The insitu calibration was performed by moving the 252Cf neutron source toroidally through the JT-60

T. Nishitani; H. Takeuchi; T. Kondoh; T. Itoh; M. Kuriyama; Y. Ikeda; T. Iguchi; Cris W. Barnes

1992-01-01

69

Program for refan JT8D engine design, fabrication and test, phase 2  

NASA Technical Reports Server (NTRS)

The objective of the JT8D refan program was to design, fabricate, and test certifiable modifications of the JT8D engine which would reduce noise generated by JT8D powered aircraft. This was to be accomplished without affecting reliability and maintainability, at minimum retrofit cost, and with no performance penalty. The mechanical design, engine performance and stability characteristics at sea-level and altitude, and the engine noise characteristics of the test engines are documented. Results confirmed the structural integrity of the JT8D-109. Engine operation was stable throughout the airplane flight envelope. Fuel consumption of the test engines was higher than that required to meet the goal of no airplane performance penalty, but the causes were identified and corrected during a normal pre-certification engine development program. Compared to the baseline JT8D-109 engine, the acoustically treated JT8D-109 engine showed noise reductions of 6 PNdB at takeoff and 11 PNdB at a typical approach power setting.

Glass, J. A.; Zimmerman, E. S.; Scaramella, V. M.

1975-01-01

70

A 727/JT8D-100 series engine exhaust system propulsion performance model test  

NASA Technical Reports Server (NTRS)

The results are presented from testing one-eighth scale models of the Pratt and Whitney aircraft reference and Boeing nozzles for the JT8D-100 series mixed flow engines. The objective of the test was to obtain the nozzle velocity and flow coefficients for the reference configurations and compare these with the Boeing configurations which incorporated a longer splitter between the fan and primary flows. A further comparison was made between the JT8D-100 series nozzles and the Boeing JT8D-9/727 production nozzle performance. A statistical analysis was used to compare configurations which showed the performance (velocity coefficient) of the reference and the Boeing configuration was the same for the JT8D-109. It also showed no difference between reference and the Boeing configuration for the JT8D-115 and no difference for the JT8D-117 nozzles. Bypass ratio (match) was shown to be equally dependent on splitter position as on nozzle area within the range investigated. The nozzles were very similar in flow coefficient within an engine family. Excellent profile data was recorded. The effects of swirl on the nozzle performance was examined and found to degrade the velocity and flow coefficients.

Haugan, W. J.; Kern, P. R. A.

1974-01-01

71

Achievement and improvement of the JT-60U negative ion source for JT-60 Super Advanced (invited)  

SciTech Connect

Developments of the large negative ion source have been progressed in the high-energy, high-power, and long-pulse neutral beam injector for JT-60 Super Advanced. Countermeasures have been studied and tested for critical issues of grid heat load and voltage holding capability. As for the heat load of the acceleration grids, direct interception of D{sup -} ions was reduced by adjusting the beamlet steering. As a result, the heat load was reduced below an allowable level for long-pulse injections. As for the voltage holding capability, local electric field was mitigated by tuning gap lengths between large-area acceleration grids in the accelerator. As a result, the voltage holding capability was improved up to the rated value of 500 kV. To investigate the voltage holding capability during beam acceleration, the beam acceleration test is ongoing with new extended gap.

Kojima, A.; Hanada, M.; Tanaka, Y.; Inoue, T.; Watanabe, K.; Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Tobari, H. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Collaboration: JT-60 NBI Group

2010-02-15

72

Achievement and improvement of the JT-60U negative ion source for JT-60 Super Advanced (invited).  

PubMed

Developments of the large negative ion source have been progressed in the high-energy, high-power, and long-pulse neutral beam injector for JT-60 Super Advanced. Countermeasures have been studied and tested for critical issues of grid heat load and voltage holding capability. As for the heat load of the acceleration grids, direct interception of D- ions was reduced by adjusting the beamlet steering. As a result, the heat load was reduced below an allowable level for long-pulse injections. As for the voltage holding capability, local electric field was mitigated by tuning gap lengths between large-area acceleration grids in the accelerator. As a result, the voltage holding capability was improved up to the rated value of 500 kV. To investigate the voltage holding capability during beam acceleration, the beam acceleration test is ongoing with new extended gap. PMID:20225407

Kojima, A; Hanada, M; Tanaka, Y; Inoue, T; Watanabe, K; Taniguchi, M; Kashiwagi, M; Umeda, N; Tobari, H; Grisham, L R

2010-02-01

73

Control of Current Profile and Instability by Radiofrequency Wave Injection in JT-60U and Its Applicability in JT-60SA  

SciTech Connect

Recent results of control of current profile and instability using radiofrequency wave in JT-60U and prediction analysis in JT-60SA are descried. In JT-60U, control of current profile in high-beta regime was demonstrated by using a real-time system, where the motional Stark effect diagnostic and lower hybrid wave were used as a detector and actuator, respectively. The minimum value of the safety factor was raised from 1.3 to 1.7 so as to follow the commanded value. Complete stabilization of a neoclassical tearing mode (NTM) with the poloidal mode number m = 2 and the toroidal mode number n = 1 was demonstrated using electron cyclotron (EC) current drive. By scanning the location of EC current drive in detail, strong stabilization effect was found for misalignment less than about half of the full island width. In addition, destabilization of the 2/1 NTM was observed for misalignment comparable to the full island width. Simulation of NTM stabilization in JT-60SA was performed by using the TOPICS code combined with the modified Rutherford equation. The TOPICS simulation showed that complete stabilization can be achieved more effectively by optimizing the EC wave injection angle and modulating the EC wave.

Isayama, A.; Suzuki, T.; Hayashi, N.; Ide, S.; Hamamatsu, K.; Fujita, T.; Hosoyama, H.; Kamada, Y.; Oyama, N.; Ozeki, T.; Sakata, S.; Seki, M.; Sueoka, M.; Takechi, M.; Urano, H. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Nagasaki, K. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2007-09-28

74

B747/JT9D flight loads and their effect on engine running clearances and performance deterioration; BCAC NAIL/P and WA JT9D engine diagnostics programs  

NASA Technical Reports Server (NTRS)

Flight loads on the 747 propulsion system and resulting JT9D blade to outer airseal running clearances during representative acceptance flight and revenue flight sequences were measured. The resulting rub induced clearance changes, and engine performance changes were then analyzed to validate and refine the JT9D-7A short term performance deterioration model.

Olsson, W. J.; Martin, R. L.

1982-01-01

75

The JT9D Jet Engine Diagnostics Program  

NASA Technical Reports Server (NTRS)

The various engine deterioration phenomena that affect JT9D performance retention were studied, and approaches to improve performance retention of engines were identified. The program included surveys of historical data, monitoring of in service engines, ground and flight testing of instrumented engines, analysis, and analytical modeling. Performance deterioration is made up of both short and long term modes, both of which are flight cycle related phenomena. Short term deterioration occurs primarily during airplane acceptance testing prior to delivery to the airline. This effect is caused by flight load and power induced clearance closures and engine deflections with resulting rubbing of airfoils and seals. Long term deterioration is caused by erosion of airfoils and gas path seals during ground operation and take off and by cyclic induced thermal distortion of the high pressure turbine airfoils. Studies of possible remedial approaches have shown that performance retention within 1 to 2 percent of initial revenue service performance can be achieved with a proper program of hot section and cold section maintenance.

Olsson, W. J.

1982-01-01

76

Present knowledge about the materials behavior in JT-60  

NASA Astrophysics Data System (ADS)

JT-60 first walls were originally composed of a number of tiles made of either molybdenum or Inconel 625 with 20 ?m thick TiC coating. These first walls, operated after the bakeout at a temperature of 350°C, provided very clean surfaces as well as superior plasma characteristics during Joule heating discharges. Damage of the TiC-coated first walls was modest and localized to specific spots. However, initial results of the additional heating experiments showed degrading effects of locally melted TiC-coated molybdenum and Inconel 625 on the plasma operation. During the venting period from April to May '87 about half of the TiC-coated molybdenum and Inconel 625 was replaced by graphite first walls to prepare for high-power and long-pulse additional heating experiments. After a three-day 300 °c bakeout, 30 h glow discharge cleaning, and 16 h pulsed discharge cleaning at a vessel temperature of around 250°C, a very rapid start-up of the discharge conditioning with plasma current up to 1.0 MA was achieved with 14 shots. Flexibility in plasma operation was increased and the plasma current was increased to 2.9 MA.

Takatsu, H.; Ando, T.; Yamamoto, M.; Arai, T.; Kodama, K.; Ohkubo, M.; Shimizu, M.

1988-07-01

77

Antimisting kerosene JT3 engine fuel system integration study  

NASA Technical Reports Server (NTRS)

An analytical study and laboratory tests were conducted to assist NASA in determining the safety and mission suitability of the modified fuel system and flight tests for the Full-Scale Transport Controlled Impact Demonstration (CID) program. This twelve-month study reviewed and analyzed both the use of antimisting kerosene (AMK) fuel and the incorporation of a fuel degrader on the operational and performance characteristics of the engines tested. Potential deficiencies and/or failures were identified and approaches to accommodate these deficiencies were recommended to NASA Ames -Dryden Flight Research Facility. The result of flow characterization tests on degraded AMK fuel samples indicated levels of degradation satisfactory for the planned missions of the B-720 aircraft. The operability and performance with the AMK in a ground test engine and in the aircraft engines during the test flights were comparable to those with unmodified Jet A. For the final CID test, the JT-3C-7 engines performed satisfactorily while operating on AMK right up to impact.

Fiorentino, A.

1987-01-01

78

Oxygen chemisorption compressor study for cryogenic J-T refrigeration  

NASA Technical Reports Server (NTRS)

Over twenty potentially reversible heat-powered oxide reactions have been studied and/or tested to determine their potential use as thermochemical oxygen compressors for cryogenic J-T LO2 refrigerators. One gas-solid compound family, Pr(1-n)Ce(n)O(x), proved to be completely reversible with fast kinetics for all pressure ranges tested below 650 C. With a heat-powered charcoal/methane physical adsorption upper stage and a Pr(1-n)Ce(n)O(x) chemisorption lower stage, temperatures should be attainable in the 55-80 K range for less power and over five times less weight than for charcoal/nitrogen sorption refrigeration systems. Total system power requirements with a hydride chemisorption lower stage (10 K to 7 K minimum) are about three times less than any mechanical refrigerator, and spacecraft refrigeration weights are about twenty times less. Due to the lack of wear-related moving parts in sorption refrigerators, life expectancy is at least ten years, and there essentially no vibration.

Jones, Jack A.; Blue, Gary D.

1987-01-01

79

Oxygen chemisorption compressor study for cryogenic J-T refrigeration  

NASA Astrophysics Data System (ADS)

Over twenty potentially reversible heat-powered oxide reactions have been studied and/or tested to determine their potential use as thermochemical oxygen compressors for cryogenic J-T LO2 refrigerators. One gas-solid compound family, Pr(1-n)Ce(n)O(x), proved to be completely reversible with fast kinetics for all pressure ranges tested below 650 C. With a heat-powered charcoal/methane physical adsorption upper stage and a Pr(1-n)Ce(n)O(x) chemisorption lower stage, temperatures should be attainable in the 55-80 K range for less power and over five times less weight than for charcoal/nitrogen sorption refrigeration systems. Total system power requirements with a hydride chemisorption lower stage (10 K to 7 K minimum) are about three times less than any mechanical refrigerator, and spacecraft refrigeration weights are about twenty times less. Due to the lack of wear-related moving parts in sorption refrigerators, life expectancy is at least ten years, and there essentially no vibration.

Jones, Jack A.; Blue, Gary D.

1987-06-01

80

75 FR 62319 - Airworthiness Directives; Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines  

Federal Register 2010, 2011, 2012, 2013

...Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines AGENCY...Whitney (PW) JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines. This...applies to PW JT8D-9, -9A, -11, - 15, -17, and -17R turbofan engines....

2010-10-08

81

75 FR 27972 - Airworthiness Directives; Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines  

Federal Register 2010, 2011, 2012, 2013

...Pratt & Whitney JT8D-9, -9A, -11, -15, -17, and -17R Turbofan Engines AGENCY...Whitney (PW) JT8D-9, -9A, -11, -15, -17, and -17R turbofan engines. This...Whitney (PW) JT8D-9, -9A, -11, - 15, -17, and -17R turbofan engines....

2010-05-19

82

A 727 Airplane Center Duct Inlet Low Speed Performance Confirmation Model Test for Refanned Jt8d Engines, Phase 2.  

National Technical Information Service (NTIS)

The results from testing of a 0.3 scale model center duct inlet (S duct) for the Pratt and Whitney Aircraft JT8D-100 engines are presented. The objective of this test was to demonstrate that the required airflow of the JT8D-100 engine (480 lb/sec as compa...

G. Kaldschmidt B. E. Syltebo C. T. Ting

1973-01-01

83

Relationship between the cooldown characteristics of J-T refrigerators and mixture composition  

NASA Astrophysics Data System (ADS)

The performance of Joule-Thomson (J-T) refrigerators is strongly influenced by the composition of the refrigerant mixture used. The mixture composition changes if leaks occur, or when a silica-gel drier is used in the system. In this experimental study, we show how the composition changes can be estimated from the cooldown characteristics of J-T refrigerators without using a gas chromatograph. A novel way of representing the cooldown characteristics of J-T refrigerators is presented. The variation of compressor power during the cooldown is also discussed. The results presented here are useful for developers as well as field service engineers in selectively modifying the composition without discarding the entire mixture.

Rajesh Reddy, K.; Srinivasa Murthy, S.; Venkatarathnam, G.

2010-06-01

84

Atomization and combustion characteristics of antimisting fuels using JT8D and air-boost injectors  

NASA Technical Reports Server (NTRS)

The atomization levels of antimisting fuels are presently determined for a JT8D fuel injector, a low emission airblast JT8D injector, and an air-boost injector, at operating conditions simulating engine operating conditions. The effects of the use of antimisting kerosene (AMK) on component performance are also studied in the case of an in-service JT8D engine. The use of the AMK fuel causes a decline in the quality of the spray, most notably as a large increase in the Sauter mean diameter for all three injector types. In addition, the idle patternation data obtained indicate that the low emission injector fuel distribution changed from a hollow cone Jet A spray having no fuel at its center to a semihollow spray cone in the case of AMK; this change could disrupt the combustor primary zone recirculation pattern.

Kennedy, J. B.; Florentino, A. J.

1986-01-01

85

Summary and analysis of performance and stability characteristics of the refan JT8D-109 engine  

NASA Technical Reports Server (NTRS)

The refan JT8D-109 performance and stability characteristics are reported as determined from sea level testing, altitude testing, and DC-9 flight testing. The test results are summarized as follows: (1) TSFC at SLS achieved design goal of 12.66 percent reduction. (2) TSFC at altitude average cruise power 0.5 percent higher than design goal, (3) TSFC at altitude maximum cruise power 1.7-3.7 percent higher than design goal, (4) ground starting consistent with JT8D-9 base engine, (5) successful flight starts without starter assist, (6) transient surge margin equivalent to JT8D-9, (7) stable engine operation with inlet distortion, and (8) stable engine operation during snap acceleration and deceleration. A flight idle setting is required for acceptable aborted-landing go-around acceleration time due to increase in low-rotor moment of inertia, and a performance improvement program should be conducted as part of any future certification program.

Sanberg, K. G.; Mogielnicki, R. M.; Davis, J. C.; Scaramella, V. M.

1975-01-01

86

Pollution reduction technology program for class T4(JT8D) engines  

NASA Technical Reports Server (NTRS)

The technology required to develop commercial gas turbine engines with reduced exhaust emissions was demonstrated. Can-annular combustor systems for the JT8D engine family (EPA class T4) were investigated. The JT8D turbofan engine is an axial-flow, dual-spool, moderate-bypass-ratio design. It has a two-stage fan, a four-stage low-pressure compressor driven by a three-stage low-pressure turbine, and a seven-stage high-pressure compressor driven by a single-stage high-pressure turbine. A cross section of the JT8D-17 showing the mechanical configuration is given. Key specifications for this engine are listed.

Roberts, R.; Fiorentino, A. J.; Diehl, L. A.

1977-01-01

87

Development of a cryogenic mixed fluid J-T cooling computer code, 'JTMIX'  

NASA Technical Reports Server (NTRS)

An initial study was performed for analyzing and predicting the temperatures and cooling capacities when mixtures of fluids are used in Joule-Thomson coolers and in heat pipes. A computer code, JTMIX, was developed for mixed gas J-T analysis for any fluid combination of neon, nitrogen, various hydrocarbons, argon, oxygen, carbon monoxide, carbon dioxide, and hydrogen sulfide. When used in conjunction with the NIST computer code, DDMIX, it has accurately predicted order-of-magnitude increases in J-T cooling capacities when various hydrocarbons are added to nitrogen, and it predicts nitrogen normal boiling point depressions to as low as 60 K when neon is added.

Jones, Jack A.

1991-01-01

88

MHD Equilibrium Analysis Method of JT-60 Based on Magnetic Measurements.  

National Technical Information Service (NTIS)

A code has been developed to calculate MHD equilibrium configuration in JT-60 from magnetic pick-up signals, plasma current, and external coil currents. To investigate equilibrium configuration, we must seek out a solution of Grad-Shafranov equation which...

1986-01-01

89

Progress in Physics and Technology Developments for the Modification of JT-60  

Microsoft Academic Search

Recent progress in the physics and engineering design study for the modification programme of JT-60 is presented. In order to achieve a steady state high-beta plasma operation, which is the dominant issue of this programme, physics design for the MHD control and the stability analysis is investigated. Engineering design and the R & D for the superconducting coils, irradiation shield

H. Tamai; M. Matsukawa; G. Kurita; N. Hayashi; K. Urata; Y M Miura; K. Kizu; K. Tsuchiya; A. Morioka; Y. Kudo; S. Sakurai; K. Masaki; T. Suzuki; M. Takechi; Y. Kamada; A. Sakasai; S. Ishida; K. Abe; A. Ando; T. Cho; T. Fujii; T. Fujita; S. Goto; K. Hananda; A. Hatayama; T. Hino; H. Horiike; N. Hosogane; M. Ichimura; S. Tsuji-Iio; S. Itoh; M. Katsurai; M. Kikuchi; A. Kohyama; H. Kubo; M. Kuriyama; M. Matsuoka; N. Miya; T. Mizuuchi; K. Nagasaki; H. Ninomiya; N. Nishino; Y. Ogawa; K. Okano; T. Ozeki; M. Saigusa; M. Sakamoto; M. Satoh; M. Shimada; R. Shimada; M. Shimizu; T. Takagi; Y. Takase; T. Tanabe; K. Toi; Y. Ueda; Y. Uesugi; K. Ushigusa; Y. Yagi; T. Yamamoto; K. Yatsu; K. Yoshikawa

2004-01-01

90

Design study of a negative-ion based NBI system for JT-60U.  

National Technical Information Service (NTIS)

A high energy negative-ion based NBI system for JT-60U has been designed. The objective of the NBI system is to demonstrate mega-ampere level NB current drive and plasma core heating in a reactor-grade high density plasma. This is the first negative-ion b...

N. Akino M. Araki N. Ebisawa

1994-01-01

91

Development of the computer system for the JT-60 negative-ion based NBI.  

National Technical Information Service (NTIS)

The negative-ion based NBI system (N-NBI) for JT-60 is the first NBI system using a negative-ion source in the world. The N-NBI is designed to deliver a neutral beam injection power of 10 MW at 500 keV. The computer for the N-NBI system is composed of UNI...

M. Kawai H. Oohara A. Honda M. Kuriyama T. Aoyagi

1997-01-01

92

Review of Preliminary Additional Heating Experiments in JT-60 (August-November 1986).  

National Technical Information Service (NTIS)

This is a prompt report on preliminary additional heating experiments in JT-60 from August to November in 1986. Neutral beam heating power was raised up to 20 MW in about a month. Plasma stored energy is about 2 MJ and energy confinement time is 0.1 -- 0....

1987-01-01

93

Design and installation of W-shaped divertor in JT-60U.  

National Technical Information Service (NTIS)

JT-60 divertor was modified to W-shaped divertor to realize good energy confinement and radiative divertor simultaneously, and to improve divertor function. Design activity of the W-shaped divertor was started in 1995. The modification work was completed ...

K. Kodama K. Masaki T. Sasajima

1998-01-01

94

Design Status of the Cryogenic System and Operation Modes Analysys of the JT-60SA Tokamak  

NASA Astrophysics Data System (ADS)

The JT-60SA project is part of the Broader Approach Programme signed between Japan and Europe. This superconducting upgrade of the existing JT-60U tokamak in Naka, Japan shall start operation in 2016 and shall support ITER exploitation and research towards DEMO fusion reactor. JT-60SA is currently in the basic design phase. The cryogenic system of JT-60SA shall provide supercritical helium to cool the superconducting magnets and their structures at 4.4 K, and the divertor cryopumps at a temperature of 3.7 K. In addition it shall provide refrigeration for the thermal shields at 80 K and deliver helium at 50 K for the current leads. The equivalent refrigeration capacity at 4.5 K will be about 10 kW. The refrigeration process has to be optimised for different operation modes. During the day, in plasma operation state, the refrigerator will cope with the pulsed heat loads which may increase up to 100% of the average power, representing a big challenge compared to other tokamaks. Fast discharge quenches of the magnets, the impact from baking of the vacuum vessel, cool down and warm up modes are presented from the cryogenic system point of view and their impact on the cryogenic design is described.

Roussel, P.; Hoa, C.; Lamaison, V.; Michel, F.; Reynaud, P.; Wanner, M.

2010-04-01

95

Development of automatic control method for cryopump system for JT-60 neutral beam injector.  

National Technical Information Service (NTIS)

A cryopump system for JT-60 neutral beam injector (NBI) is composed of 14 cryopumps with the largest total pumping speed of 20000 m(sup 3)/s in the world, which are cooled by liquid helium through a long-distance liquid helium transferline of about 500 m ...

K. Shibanuma N. Akino M. Dairaku Y. Ohuchi T. Shibata

1991-01-01

96

Performance and development of heating and current drive systems in JT-60U  

Microsoft Academic Search

RF systems of ECH, LH, ICH, and positive and negative ion based NBI systems are equipped in JT-60U to realize highly integrated performance plasma. Their performance and development are presented. The ECH system with the total output of 4 MW at 110 GHz has been developed using four 1 MW gyrotrons. The gyrotron has achieved 1 MW, 5 sec output

T. Fujii; A. Kasugai

2003-01-01

97

Operational progress of the 110GHz4MW ECRF heating system in JT-60U  

Microsoft Academic Search

The JT-60U electron cyclotron range of frequency (ECRF) heating system is utilized to realize high performance plasma. Its output power is 4 MW at 110 GHz. The output power of the gyrotron used in the heating system can be controlled by changing its anode voltage. Then, a compact anode voltage controller was developed to modulate the injected power into plasmas.

T. Fujii; M. Seki; S. Moriyama; M. Terakado; S. Shinozaki; S. Hiranai; S. Shimono; K. Hasegawa; K. Yokokura

2005-01-01

98

Initial results of electron cyclotron range of frequency (ECRF) operation and experiments in JT-60U  

Microsoft Academic Search

The 110 GHz 1 MW electron cyclotron range of frequency (ECRF) system was designed and constructed on JT-60U to locally heat and control the plasmas. The gyrotron has a diamond window to transmit RF power with Gaussian mode, which is easily transformed to HE11 mode for the transmission line of the corrugated waveguide. The second diamond window is installed at

Y. Ikeda; A. Kasugai; K. Takahashi; K. Kajiwara; A. Isayama; S. Ide; M. Terakado; S. Shinozaki; K. Yokokura; K. Anno; M. Shimono; S. Hiranai; K. Haga; A. Kajiyama; S. Moriyama; M. Tsuneoka; K. Sakamoto; K. Hamamatsu; T. Oikawa; Y. Kamada; O. Naito; M. Seki; K. Ushigusa; T. Imai; T. Yamamoto; T. Fujii

2001-01-01

99

DC-9 flight demonstration program with refanned JT8D engines. Volume 1: Summary  

NASA Technical Reports Server (NTRS)

The design, analysis, fabrication, and ground and flight testing of DC-9 airframe/nacelle hardware with prototype JT8D-109 engines are discussed. The installation of the JT8D-109 engine on the DC-9 Refan airplane required new or modified hardware for the pylon, nacelle, and fuselage. The acoustic material used in the nose cowl was bonded aluminum honeycomb sandwich and the exhaust duct acoustic material was Inconel 625 Stresskin. The sea level static, standard day bare engine takeoff thrust, the cruise TSFC and the maximum available cruise thrust for the JT8D-109 engine were compared with those of the JT8D-9 engine. The range capabilities of the DC-9 Refan and the production DC-9 airplane were also compared. The Refan airplane demonstrated flight characteristics similar to the production DC-9-30 and satisfied airworthiness requirements. Flyover noise levels were determined for the DC-9 Refan and the DC-9 C-9A airplane for takeoff and landing conditions. Cost estimates were also made.

1975-01-01

100

Solution for a window coating problem developed in the JT-60U Thomson scattering system.  

National Technical Information Service (NTIS)

For an exact measurement of fusion plasmas with higher electron temperature, the following two methods which can solve a window coating problem were developed in the JT-60U Thomson scattering system. One is an in situ monitoring method which can infer a w...

H. Yoshida O. Naito T. Hatae A. Nagashima

1996-01-01

101

Influence of External Magnetic Field on AC Losses at EF Coil Joints of JT-60SA  

Microsoft Academic Search

We experimentally and numerically evaluated the AC loss occurred in joints of the EF coil in JT60-SA. There are two kinds of the joints (pancake joint and terminal joint) in the EF coil. Firstly, the AC losses of the joints were experimentally obtained. The experimental results showed that the AC losses in the pancake and the terminal joints were smaller

Tomoaki Takao; Kazuya Nakamura; Toshiyuki Takagi; Naoki Tanoue; Haruyuki Murakami; Kiyoshi Yoshida

2012-01-01

102

Feedback control of radiation region in radiative divertor plasma on JT-60U tokamak  

Microsoft Academic Search

The sustainment of radiative divertor plasma in JT-60U is performed by the feedback control of the gas puffing rate into the divertor region with an actuator of the divertor radiation power. The feedback control system switches the piezoelectric gas valve every 10 ms, so that the proper amount of gas flux is fed for divertor radiation power to follow the

H. Tamai; S. Konoshima; N. Hosogane; N. Asakura; S. Sakata; N. Saito; K. Akiba; H. Akasaka; Y. Kawamata; K. Kurihara

1998-01-01

103

Development of a Micro-Flow Piezoelectric Valve for JT-60.  

National Technical Information Service (NTIS)

A micro-flow piezoelectric gas valve (PEV-LL) for JT-60 has been developed. Remarkables of the valve are summarized as follows: (1) PEV-LL is the same form an appearance small-flow piezoelectric valve (PEV-L); (2) The maximum throughput rate, responce tim...

H. Hiratsuka K. Kawasaki

1987-01-01

104

Current drive and sustain experiments with the bootstrap current in JT-60.  

National Technical Information Service (NTIS)

The current drive and sustain experiments with the neoclassical bootstrap current are performed in the JT-60 tokamak. It is shown that up to 80% of total plasma current is driven by the bootstrap current in extremely high (beta)(sub p) regime ((beta)(sub ...

M. Kikuchi M. Azumi K. Tani S. Tsuji H. Kubo

1989-01-01

105

Mixed-refrigerant Joule-Thomson (MR JT) mini-cryocoolers  

NASA Astrophysics Data System (ADS)

This paper presents the progress in our ongoing research on Mixed-Refrigerant (MR) Joule-Thomson (JT) cryocoolers. The research begun by exploring different MRs and testing various compressors: oil-lubricated and oil-free, reciprocating and linear, custom-made and commercial. Closed-cycle JT cryocoolers benefit from the fact that the compressor might be located far from the cold-end and thus there are no moving parts, no vibrations, and no heat emission near the cold-end. As a consequence, the compressor may be located where there are no severe size limitations, its heat can be conveniently removed, and it can be easily maintained. However, in some applications there is still a demand for a small compressor to drive a JT cryocooler although it is located far from the cooled device. Recently, we have developed a miniature oil-free compressor for MR JT cryocoolers that weighs about 700 g and its volume equals about 300 cc. The cryocooler operates with a MR that contains Ne, N2, and Hydrocarbons. This MR has been widely investigated with different compressors and varying operating conditions and proved to be stable. The current research investigates the performances of MR JT mini-cryocooler operating with the MR mentioned above, driven with our miniature compressor, and a cold-finger prototype. A Dewar with heat load of about 230 mW is cooled to about 80 K at ambient temperatures between 0°C and 40°C. The experimental results obtained are stable and demonstrate the ability to control the cooling temperature by changing the rotation speed of the compressor.

Tzabar, Nir

2014-01-01

106

The Jahn-Teller (jt) Effect in the widetilde{A} State of the Nitrate Radical NO_3  

NASA Astrophysics Data System (ADS)

The JT effect in the widetilde{A}^2E^'' of NO_3 is poorly understood. A preliminary spectrum of the vibronically-allowed widetilde{A}?widetilde{X} transition, coupled with ab initio calculations, shows moderate JT activity in the widetilde{A} state. Vibronic bands exhibit either static or dynamic JT distortions depending on the vibrational level of the upper widetilde{A} state. The picture of the widetilde{A} state is however incomplete. For example, in the E^''?e^'=a_1^''?a_2^''?e^'' manifold, while the splitting would provide a direct measure of the JT strength, only the a_1^'' levels have been observed. We have gained new insight into the widetilde{A} state by examining the hot bands of NO_3 which access previously unobserved dark levels of the widetilde{A} state.

Takematsu, Kana; Eddingsaas, Nathan; Okumura, Mitchio; Stanton, John

2009-06-01

107

Present status of the negative ion based NBI system for long pulse operation on JT-60U  

Microsoft Academic Search

The 500 keV negative-ion based neutral beam injector for JT-60U started operations in 1996. The availability of the negative ion based neutral beam injection system has been improved gradually by modifying the ion source and optimizing its operation parameters. Recently, the extension of the pulse duration up to 30 s has been intended to study quasi-steady state plasma on JT-60U.

Y. Ikeda; N. Umeda; N. Akino; N. Ebisawa; L. Grisham; M. Hanada; A. Honda; T. Inoue; M. Kawai; M. Kazawa; K. Kikuchi; M. Komata; K. Mogaki; K. Noto; F. Okano; T. Ohga; K. Oshima; T. Takenouchi; Y. Tanai; K. Usui; H. Yamazaki; T. Yamamoto

2006-01-01

108

Development of TiC coated wall materials for JT-60  

NASA Astrophysics Data System (ADS)

Development of titanium carbide (TiC, 20 ?m thick) coated wall materials has been carried out for JT-60. Application of TiC coatings onto molybdenum and Inconel 625 substrates requires a deposition temperature below 950°C and 600°C respectively, because recrystallization of molybdenum and age hardening of Inconel 625 occur above these temperatures. Through this process of coating we developed a new type plasma CVD(TP-CVD method) for molybdenum and a new type PVD(HCD-ARE method) for Inconel 625 which could successfully reduce the deposition temperature to 900°C and 500°C, respectively. The TiC coated wall samples were characterized by AES, ESCA, X-ray diffractometer, EPMA, SEM, metallography, tensile tests, thermal shock tests, and others techniques. As a results of the above measurements, it was demonstrated that the characteristics of those TiC coated walls satisfy the requirements arising from JT-60 operation conditions.

Abe, T.; Murakami, Y.; Obara, K.; Hiroki, S.; Nakamura, K.; Mizoguchi, T.; Doi, A.; Inagawa, K.

1985-08-01

109

Heating and Current Drive by N-NBI in JT-60U and LHD  

SciTech Connect

Two pilot facilities of advanced negative-ion-based neutral beam injection heating system have been working successfully on the JT-60U tokamak and the LHD heliotron in Japan. These were the first applications of negative-ion technology to the production of high current neutral beam for plasma heating as well as current drive. High energy deuterium beam of 400 keV (5.8 MW) was injected in JT-60U for efficient current drive, and high power hydrogen beam of 9.0 MW (160 keV) was injected in LHD producing high performance plasmas. These results demonstrate the feasibility of negative ion beam system for future fusion reactors such as ITER.

Kaneko, O. [National Institute for Fusion Science (Japan); Yamamoto, T. [Japan Atomic Energy Research Institute (Japan); Akiba, M. [Japan Atomic Energy Research Institute (Japan); Hanada, M. [Japan Atomic Energy Research Institute (Japan); Ikeda, K. [National Institute for Fusion Science (Japan); Inoue, T. [Japan Atomic Energy Research Institute (Japan); Nagaoka, K. [National Institute for Fusion Science (Japan); Oka, Y. [National Institute for Fusion Science (Japan); Osakabe, M. [National Institute for Fusion Science (Japan); Takeiri, Y. [National Institute for Fusion Science (Japan); Tsumori, K. [National Institute for Fusion Science (Japan); Umeda, N. [Japan Atomic Energy Research Institute (Japan); Watanabe, K. [Japan Atomic Energy Research Institute (Japan)

2003-09-15

110

Finite element-integral acoustic simulation of JT15D turbofan engine  

NASA Astrophysics Data System (ADS)

An iterative finite element integral technique is used to predict the sound field radiated from the JT15D turbofan inlet. The sound field is divided into two regions: the sound field within and near the inlet which is computed using the finite element method and the radiation field beyond the inlet which is calculated using an integral solution technique. The velocity potential formulation of the acoustic wave equation was employed in the program. For some single mode JT15D data, the theory and experiment are in good agreement for the far field radiation pattern as well as suppressor attenuation. Also, the computer program is used to simulate flight effects that cannot be performed on a ground static test stand.

Baumeister, K. J.; Horowitz, S. J.

1984-07-01

111

Suppression of NTM Towards Stationary High-Beta Plasmas in JT-60U  

NASA Astrophysics Data System (ADS)

Results from stabilization of neoclassical tearing modes (NTMs) in JT-60U are described. NTM stabilization and confinement improvement have been demonstrated by employing a real-time NTM stabilization system, where the identification of the location of an NTM and the optimization of the injection angle of the electron cyclotron wave are performed in real time. Also, a high-beta plasma with the normalized beta of 3 has been sustained by suppressing NTM by applying the electron cyclotron current drive (ECCD) before the onset (`preemptive ECCD'). In addition, a simulation code for analysis of the NTM evolution has been developed by combining the modified Rutherford equation with the transport code TOPICS. It is found that the simulation well reproduces the NTM behavior in JT-60U. The simulation also shows that the ECCD width is also important for NTM stabilization, and that the EC wave power for complete stabilization can be reduced by narrowing the ECCD profile.

Isayama, A.; JT-60 Team

2006-01-01

112

Design of a 500 KEV negative-ion-based NBI system for JT-60U  

Microsoft Academic Search

The design of a negative-ion-based NBI system for JT-60U rated to inject neutral beams of 500 keV, 10 MW for 10 seconds is described. The neutral beam is injected tangentially from a beamline with two ion sources. The ion source is a cesium-seeded multicusp volume source. The acceleration current per source is 22 A with deuterium at a current density

M. Mizuno; M. Akiba; N. Akino; M. Araki; N. Ebisawa; M. Hanada; T. Inoue; M. Kawai; M. Kazawa; J. Koizumi; S. Kunieda; M. Kuriyama; M. Matsuoka; Y. Ohara; T. Ohga; Y. Okumura; H. Oohara; J. Satoh; S. Suzuki; S. Takahashi; M. Tanaka; K. Watanabe; M. Yamamoto; T. Yamazaki

1994-01-01

113

Improvement of beam performance in the negative-ion based NBI system for JT-60U  

Microsoft Academic Search

The injection performance of the negative-ion based NBI (N-NBI) system for JT-60U has been improved by correcting beamlet deflection and improving spatial uniformity of negative ion production. Beamlet deflection at the peripheral region of the grid segment due to the distorted electric field at the bottom of the extractor has been observed. This was corrected by modifying the surface geometry

N. Umeda; L. R. Grisham; T. Yamamoto; M. Kuriyama; M. Kawai; T. Ohga; K. Mogaki; N. Akino; H. Yamazaki; K. Usui; A. Honda; L. Guangjiu; K. Watanabe; T. Inoue; M. Hanada; M. Kashiwagi; T. Morishita; M. Dairaku; T. Takayanagi

2003-01-01

114

High voltage power supply of negative-ion based NBI for JT-60U  

Microsoft Academic Search

The power supply for the negative-ion based NBI system for JT-60U is composed of negative-ion generation, extraction and acceleration power supplies. The acceleration power supply is used to accelerate negative ions up to 500 keV and has a function of power cut off within 200 ?sec for protecting the grid of the accelerator and the power supply itself by a

T. Ohga; K. Usui; K. Ohmori; K. Watanabe; K. Ohshima; T. Itoh; M. Kawai; M. Kuriyama

1997-01-01

115

Heating and non-inductive current drive by negative ion based NBI in JT-60U  

Microsoft Academic Search

The current drive and heating properties of negative ion based NBI have been studied comprehensively in JT-60U. It has been confirmed from shine-through measurements of the injected beam (350 keV) that multistep ionization processes are essential in the ionization processes of high energy particles. The profile of the current density driven by a negative ion based NB (N-NB) has been

T. Oikawa; K. Ushigusa; C. B. Forest; M. Nemoto; O. Naito; Y. Kusama; Y. Kamada; K. Tobita; S. Suzuki; T. Fujita; H. Shirai; T. Fukuda; M. Kuriyama; T. Itoh; Y. Okumura; K. Watanabe; L. Grisham

2000-01-01

116

One-Dimensional Activation Analysis of Vacuum Vessel of JT-60U with Deuterium Gas Discharges  

Microsoft Academic Search

Identification of radionuclides and evaluation of dose rate level around a vacuum vessel of JT-60U tokamak device have been made. A one-dimensional calculation code was employed in this work. Radionuclides of Mn (High-Mn steel of toroidal field coil case), Co (Inconel-625 vessel) and Co (SS-316 material of first wall) appeared after shutdown of operation with deuterium gases. Cobalt-58 and Co

Naoyuki MIYA; Takeo NISHITANI; Hiroshi TAKEUCHI

1994-01-01

117

Research and Development on the Ion Cyclotron Range of Frequency Heating System in JT-60U  

SciTech Connect

Research and developments on the ion cyclotron range of frequency (ICRF) heating system in the JT-60 upgrade (JT-60U) are presented. The developments and experiences on the operation of the ICRF heating system contribute to its upgrade and to future ICRF heating systems in ITER. The ICRF heating system for JT-60U started operation in January 1992. RF power up to 7 MW for 1.1 sec at 116 MHz has been coupled to a plasma as a result of the developments described in this paper. New high power tetrodes having pyrolitic graphite grids for higher dissipation of screen and control grids were tested in the ICRF amplifier, and 1.7 MW of the output power at 131 MHz for 5.4 seconds was achieved. This was the highest power level for fusion research above 110 MHz in 1990. A pair of phased loop antenna arrays (2 x 2) showed sufficiently high coupling resistance. To keep the impedance matching between the antenna and the transmission line, a frequency feedback control (FFC) system was developed, and its effectiveness was proved to couple high power RF continuously to the variable plasma. In ITER, enhancement of dielectric loss tangent of ceramics due to neutron irradiation will limit power injection capability of the antenna significantly. To solve this problem, an all-metal support (AMS) was developed in the JT-60U ICRF heating system as a substitute for a ceramic support of a central conductor of a coaxial antenna feeder in the ITER ICRF antenna.

Moriyama, S. [Japan Atomic Energy Research Institute (Japan); Fujii, T. [Japan Atomic Energy Research Institute (Japan); Kimura, H. [Japan Atomic Energy Research Institute (Japan); Anno, K. [Japan Atomic Energy Research Institute (Japan); Yokokura, K. [Japan Atomic Energy Research Institute (Japan); Shinozaki, S. [Japan Atomic Energy Research Institute (Japan); Terakado, M. [Japan Atomic Energy Research Institute (Japan); Hiranai, S. [Ibaraki University (Japan)

2002-09-15

118

Design considerations of a CAMAC system for large tokamak JT-60  

Microsoft Academic Search

Microprocessor based distributed intelligence CAMAC system is adopted in control and monitoring of a large tokamak device JT-60. Such novel techniques as hierarchical serial highways, auxiliary controllers with standard highway ports, a variable word-length data transfer, byte serial data transfer with single cable of optical fiber pair, hand-shaking timing system with error recovery capability, flying capacitor multiplexers for temperature monitor

T. Kumahara; A. Ogata; T. Matoba; I. Kondo; Y. Suzuki

1980-01-01

119

Summary of TFTR (Tokamak Fusion Test Reactor) diagnostics, including JET (Joint European Torus) and JT-60  

SciTech Connect

The diagnostic instrumentation on TFTR (Tokamak Fusion Test Reactor) and the specific properties of each diagnostic, i.e., number of channels, time resolution, wavelength range, etc., are summarized in tables, grouped according to the plasma parameter measured. For comparison, the equivalent diagnostic capabilities of JET (Joint European Torus) and the Japanese large tokamak, JT-60, as of late 1987 are also listed in the tables. Extensive references are given to publications on each instrument.

Hill, K.W.; Young, K.M.; Johnson, L.C.

1990-05-01

120

The operational phase of negative ion beam systems on JT-60U and LHD  

Microsoft Academic Search

This paper reviews the operational phase of the negative-ion-based neutral beam systems on the JT-60U tokamak in Naka, Japan and the large helical device (LHD) stellarator in Toki, Japan. These systems were the first high power negative ion beam systems to be deployed for any application, and thus represented large advances in the state of the art for negative ion

Larry R. Grisham

2005-01-01

121

The JT-60SA Toroidal Field Conductor Reference Sample: Manufacturing and Test Results  

Microsoft Academic Search

In the framework of the JT-60SA design activities, EU home team has defined a reference layout for the Toroidal Field conductor: it is a slightly rectangular Cable-In-Conduit NbTi conductor, operating at 25.7 kA with a peak field of 5.65 T. ENEA has assigned LUVATA Fornaci di Barga the task to produce the strands and to perform cabling, whereas jacketing and

L. Muzzi; V. Corato; G. De Marzi; A. Di Zenobio; C. Fiamozzi Zignani; L. Reccia; S. Turtu; A. della Corte; P. Barabaschi; M. Peyrot; P. Bruzzone; B. Stepanov

2010-01-01

122

Technological development and progress of plasma performance on the JT-60U  

Microsoft Academic Search

The plasma performance exploration of JT-60U in advanced tokamak regimes based on high ?p and reversed shear mode operation has been conducted intensively, by using 500 keV negative-ion based neutral beam injection (N-NBI) and 110 GHz electron cyclotron (EC) systems for plasma heating and current drive, and a repetitive centrifugal pellet injector for efficient core particle fueling. High power injection

T Yamamoto

2003-01-01

123

Development of a compact W-shaped pumped divertor in JT-60U  

Microsoft Academic Search

In JT-60U, the modification to a W-shaped pumped divertor will be completed in May 1997, aiming to realize sufficient reduction in heat flux to the targets and good H-mode confinement simultaneously. W-shaped geometry is optimized not only for forming radiative divertor plasmas and reducing the back flow of neutral particles but also for allowing various experimental configurations. Toroidally and poloidally

S. Sakurai; N. Hosogane; K. Masaki; K. Kodama; T. Sasajima; K. Kishiya; S. Takahashi; K. Shimizu; N. Akino; Y. Miyo; H. Hiratsuka; M. Saidoh; M. Inoue; T. Umakoshi; M. Onozuka; M. Morimoto

1998-01-01

124

Two-phase coexistence analysis of the bellows control mechanism for a J–T cryocooler  

Microsoft Academic Search

The bellows control mechanism is one of the most critical control elements in the Joule–Thomson cryocooler. In the cool-down process, the interior gas of the bellows may reach liquefaction temperature, cause vapour–liquid two phase coexistence phenomena, and achieve the quick open\\/close control function of a J–T valve. This paper establishes a transient model of a simplified bellows mechanism, investigates the

S. B. Chien; L. T. Chen

1999-01-01

125

First measurement of time-resolved neutron yield on JT-60U using a microfission chamber  

SciTech Connect

Microfission chambers, which are pencil sized ionization chamber containing fissile material inside, will be installed in the vacuum vessel as neutron monitors for International Thermonuclear Experimental Reactor (ITER). We have performed first measurements of the detector installed between the vacuum vessel and toroidal coils on JT-60U. The technical validity as a neutron monitor, such as magnetic field effect and electromagnetic noises from the plasma and heating devices, has been investigated. The detector had an excellent linearity with a {sup 235}U fission chamber as a neutron monitor on JT-60U with the standard deviation of 3% except for some noise signals. The electromagnetic noises were caused by neutral beam injection (NBI) breakdowns, probably due to long wiring between the detector and the preamplifier. In case of plasma disruption, improper signals have not been observed. The magnetic field effect also has not been observed up to 2 T. In JT-60U, we confirmed availability of the micro fission chamber as a neutron monitor over three decades of neutron source strength up to 1.3x10{sup 16} neutrons/s with 1 ms temporal resolution. The biggest weakness in the detector was its noise sensitivity to NBI breakdowns. Therefore, by suppressing the electromagnetic noise, microfission chambers can be available as neutron monitors for ITER.

Hayashi, T.; Nishitani, T.; Ishikawa, M. [Japan Atomic Energy Research Institute, Naka-machi, Ibaraki 319-0193 (Japan)

2004-10-01

126

Conceptual Design of Divertor Cassette Handling by Remote Handling System of JT-60SA  

NASA Astrophysics Data System (ADS)

The JT-60SA aims to contribute and supplement ITER toward demonstration fusion reactor based on tokamak concept. One of the features of JT-60SA is its high power long pulse heating, causing the large annual neutron fluence. Because the expected dose rate at the vacuum vessel (VV) may exceed 1 mSv/hr after 10 years operation and three month cooling, the human access inside the VV is restricted. Therefore a remote handling (RH) system is necessary for the maintenance and repair of in-vessel components. This paper described the RH system of JT-60SA, especially the expansion of the RH rail and exchange of the divertor cassettes. The RH rail is divided into nine and three-point mounting. The nine sections can cover 225 degrees in toroidal direction. A divertor cassette, which is 10 degrees wide in toroidal direction and weighs 500kg itself due to the limitations of port width and handling weight, can be exchanged by heavy weight manipulator (HWM). The HWM brings the divertor cassette to the front of the other RH port, which is used for supporting the rail and/or carrying in and out equipments. Then another RH device receives and brings out the cassette by a pallet installed from outside the VV.

Hayashi, Takao; Sakurai, Shinji; Masaki, Kei; Tamai, Hiroshi; Yoshida, Kiyoshi; Matsukawa, Makoto

127

Plasma Current Start-up by Outboard PF Coils in JT-60U and TST-2  

SciTech Connect

Plasma current (Ip) initiation and ramp-up utilizing induction by poloidal field (PF) coils located on the outboard side of the torus were demonstrated in both conventional aspect ratio tokamak (100 kA in JT-60U) and spherical tokamak (10 kA in TST-2). In the presence of sufficient source of plasma by RF ionization (1 MW in JT-60U, 100 kW in TST-2), Ip formation is possible without the existence of a PF null, with the initial vertical field (Bv) in the direction opposite to that required for equilibrium. Utilization of the extra flux swing provided by the PF coils before Bv switches sign is important in arriving at a high enough Ip that matches Bv at the end of PF coil current ramp. In JT-60U, recharging of the OH coil was observed with only perpendicular and counter NB injection, suggesting overdrive by bootstrap current. In TST-2, a quasi-steady-state Ip of 4 kA was formed and sustained by RF power (PRF) alone, without the use of induction. The plasma current centroid of this type of plasma is located on the outboard side. The dependences of Ip on PRF and Bv were found to be weak. The results presented here offer encouragement to CS-less operation of a tokamak fusion reactor, which should have a large impact on the economic competitiveness.

Takase, Y.; Ejiri, A.; Ushigome, M. [University of Tokyo, Kashiwa 277-8561 (Japan); Hanada, K. [Kyushu University, Kasuga 816-8580 (Japan); Ide, S. [Japan Atomic Energy Research Institute, Naka 311-0193 (Japan); Mitarai, O. [Kyushu Tokai University, Kumamoto 862-8652 (Japan); Shiraiwa, S. [1-36-2-308 Hakusan, Tokyo 113-00101 (Japan)

2005-09-26

128

Stability Control for High-beta Plasmas on JT-60SA  

NASA Astrophysics Data System (ADS)

JT-60SA is designed and under construction as fully superconducting tokamak under a combined project of the ITER satellite tokamak program of EU-JA (Broader Approach Activities) and the Japanese national program. One of the main purposes of JT-60SA is the steady-state high-beta operation above the ideal no-wall beta-limit with suppressing resistive wall modes (RWMs). In order to control the RWMs, the RWM control coils and error field correction coils (EFCCs) are to be installed. The current design of these coils composes of 18 sector coils (6 coils in toroidally and 3 coils in poloidally) so as to suppress n=1-3 RWMs and to compensate various error fields. The EFCCs can also be utilized to apply the resonant magnetic perturbation to ergodize the peripheral magnetic filed structure to mitigate and avoid the large edge localized modes. The design and analysis of these in-vessel tools for high-beta plasmas on JT-60SA will be presented.

Matsunaga, G.; Takechi, M.; Sakurai, S.; Ide, S.; Matsukawa, M.; Oyama, N.; Aiba, N.; Kurita, G.; Ferro, A.; Gaio, E.; Novello, L.; Sakasai, S.; Kamada, Y.

2009-11-01

129

First measurement of time-resolved neutron yield on JT-60U using a microfission chamber  

NASA Astrophysics Data System (ADS)

Microfission chambers, which are pencil sized ionization chamber containing fissile material inside, will be installed in the vacuum vessel as neutron monitors for International Thermonuclear Experimental Reactor (ITER). We have performed first measurements of the detector installed between the vacuum vessel and toroidal coils on JT-60U. The technical validity as a neutron monitor, such as magnetic field effect and electromagnetic noises from the plasma and heating devices, has been investigated. The detector had an excellent linearity with a 235U fission chamber as a neutron monitor on JT-60U with the standard deviation of 3% except for some noise signals. The electromagnetic noises were caused by neutral beam injection (NBI) breakdowns, probably due to long wiring between the detector and the preamplifier. In case of plasma disruption, improper signals have not been observed. The magnetic field effect also has not been observed up to 2 T. In JT-60U, we confirmed availability of the micro fission chamber as a neutron monitor over three decades of neutron source strength up to 1.3×1016 neutrons/s with 1 ms temporal resolution. The biggest weakness in the detector was its noise sensitivity to NBI breakdowns. Therefore, by suppressing the electromagnetic noise, microfission chambers can be available as neutron monitors for ITER.

Hayashi, T.; Nishitani, T.; Ishikawa, M.

2004-10-01

130

Phase 2 program on ground test of refanned JT8D turbofan engines and nacelles for the 727 airplane. Volume 3: Ground tests  

NASA Technical Reports Server (NTRS)

The NASA Refan Program included full-scale performance and noise ground tests of both a current production (JT8D-15) and a refanned (JT8D-115) engine. A description of the two ground tests including detailed propulsion, noise, and structural test results is presented. The primary objectives of the total test program were comparison of JT8D-15 and JT8D-115 overall propulsion system performance and noise characteristics and determination of incremental component noise levels. Other objectives of the test program included: (1) determination of acoustic treatment effectiveness; (2) measurement of internal sound pressure levels; (3) measurement of inlet and exhaust hardware performance; (4) determination of center-engine surge margin; and (5) evaluation of certain structural characteristics associated with the 727 refan center-engine inlet duct and JT8D refan engine exhaust system. The JT8D-15 and -115 tests were conducted during September 1974 and January to March 1975, respectively. Analyses of the test data indicated that the JT8D-115, as compared to the JT8D-15, demonstrates a 12.5 percent to 13.2 percent reduction in static specific fuel consumption, and a reduction of 6 to 7 PNdB in a weighted average value of static tone corrected perceived noise level. Separated into noise components, a significant reduction was shown for the inlet fan, aft fan, exhaust duct flow, turbine, and jet noises. However, core noise was increased. Photographs of test stands and test equipment are shown.

1975-01-01

131

Addendum to papers from JT-60 NBI Group, published in Proceedings of the 13th International Conference on Ion Sources, Gatlinburg, Tennessee, September 2009  

Microsoft Academic Search

This addendum applies to two papers authored by contributors from the JT-60 NBI Group published in Proceedings of the 13th International Conference on Ion Sources, Gatlinburg, Tennessee, September 2009. This addendum provides the full list of JT-60 NBI Group and their affiliations.

N. Akino; K. Usui; Y. Endo; K. Oasa; K. Oshima; M. Kazawa; M. Kawai; K. Kikuchi; A. Kojima; M. Komata; S. Sasaki; T. Simizu; N. Seki; S. Nemoto; Y. Tanaka; K. Noto; M. Hanada; K. Mogaki

2010-01-01

132

Cryogenic performance and numerical modeling of a helium refrigerator for the JT-60SA coil test facility  

NASA Astrophysics Data System (ADS)

In the framework of the JT-60SA project, a cryogenic loop, dedicated to the tests of the JT-60SA Toroidal Field Coils, is planned to be installed at CEA Saclay. To analyze the dynamic thermal behavior of the cryogenic loop and to optimize the cryogenic process control of the coil test facility, dynamic simulations will be carried out with the software EcosimPro. This paper deals with the validation of the software. Experimental power measurements in pure refrigeration on a helium refrigerator have been compared to computations. Results are close and allow validating the software. The modeling of the JT-60SA CTF cryogenic test loop is also described in order to give an overview of the next computations.

Serrand, Alexandre; Abdel-Maksoud, Walid; Genini, Laurent; Juster, François-Paul

2014-01-01

133

First measurement of neutron emission profile on JT-60U using Stilbene neutron detector with neutron-gamma discrimination  

NASA Astrophysics Data System (ADS)

This article describes a diagnostic for measuring neutron emission profile in JT-60U. The Stilbene neutron detector, developed by TRINITI laboratory in Russia, has been installed on the JT-60U Tokamak to measure the neutron emission profile for the first time. The Stilbene neutron detector is a detector which combines a Stilbene crystal scintillator with a neutron-gamma pulse shape discrimination circuit, with a very compact size. Performance tests were carried out using neutron and gamma-ray source prior to installation on JT-60U. Good gamma suppression of the Stilbene neutron detector was verified. Though the neutron emission profile obtained by Stilbene neutron detectors has error of 30% in innermost channel with a calculation using measured plasma parameters, there is an agreement within 10% error in the other channels.

Ishikawa, M.; Nishitani, T.; Morioka, A.; Takechi, M.; Shinohara, K.; Shimada, M.; Miura, Y.; Nagami, M.; Kaschuck, Yu. A.

2002-12-01

134

Edge pedestal characteristics in JET and JT-60U tokamaks under variable toroidal field ripple  

NASA Astrophysics Data System (ADS)

The effects of toroidal field (TF) ripple on the edge pedestal characteristics were examined in the TF ripple scan experiments at the plasma current Ip of 1.1 MA in JET and JT-60U. The TF ripple amplitude ?R was defined as a value averaged over the existing ripple wells at the separatrix on the outer midplane. By the installation of ferritic inserts (FIs), ?R was reduced from 1% to 0.6% at 3.2T (0.5% at 2.2 T) in JT-60U. In JET, ?R was varied from 0.08% to 1% by feeding different currents to the odd and even set of coils out of 32 TF coils. The pedestal pressure pped was similar for the cases before and after the installation of FIs in JT-60U. Similarly, no clear difference in pped was also observed in the variation of ?R in JET. The core and edge toroidal rotation clearly shifted in the counter-direction by increased ?R. However, there were no changes in the spatial profiles of electron density, electron temperature and ion temperature. By the installation of FIs in JT-60U, the ELM frequency fELM decreased by ~20%, while the ELM energy loss increased by 50-150%. The increased ELM loss power by 30% suggests a reduction of inter-ELM transport with the reduced ?R. In JET, fELM increased only slightly with increased ?R while the edge toroidal rotation frequency decreased as ?R increased. From the inter-machine similarity experiment at 1.1 MA, TF ripple less than 1% does not strongly affect the pedestal pressure. However, in the single TF ripple scan at the higher Ip of 2.6 MA in JET, it clearly decreases with the increased ?R, accompanying with a strong density pump out at large TF ripple. These results suggests that the effect of TF ripple on H-mode properties becomes stronger in the plasmas with higher Ip or lower edge collisionality of ripple diffusion.

Urano, H.; Saibene, G.; Oyama, N.; Parail, V.; de Vries, P.; Sartori, R.; Kamada, Y.; Kamiya, K.; Loarte, A.; Lönnroth, J.; Sakamoto, Y.; Salmi, A.; Shinohara, K.; Takenaga, H.; Yoshida, M.; JT-60 Team; EFDA Contributers, JET

2011-11-01

135

JT8D-15/17 High Pressure Turbine Root Discharged Blade Performance Improvement. [engine design  

NASA Technical Reports Server (NTRS)

The JT8D high pressure turbine blade and seal were modified, using a more efficient blade cooling system, improved airfoil aerodynamics, more effective control of secondary flows, and improved blade tip sealing. Engine testing was conducted to determine the effect of these improvements on performance. The modified turbine package demonstrated significant thrust specific fuel consumption and exhaust gas temperature improvements in sea level and altitude engine tests. Inspection of the improved blade and seal hardware after testing revealed no unusual wear or degradation.

Janus, A. S.

1981-01-01

136

Non-inductive current drive and profile control in JT-60U  

Microsoft Academic Search

Recent studies in JT-60U to establish physics base of a steady-state tokamak reactor are presented. High fusion performance with fusion triple product nD(0)?ETi(0)=1.2×1021 keVsm?3 (equivalent QDT=0.6) has been achieved transiently in the high ?pH-mode regime. By optimizing the current and pressure profiles, a quasi steady-state high ?pH-mode with nD(0)?ETi(0)=(0.4?0.5)×1021 keVsm?3 (equivalent QDT=0.25?0.36) was maintained for up to 1.5 s. In

K. Ushigusa

1995-01-01

137

Spectroscopic study of hydrogen particle behavior in attached and detached divertor plasmas of JT-60U  

NASA Astrophysics Data System (ADS)

Hydrogen particle behavior, especially H 2 molecule behavior, has been studied spectroscopically in attached and detached divertor plasmas of JT-60U. The decay lengths of the H 2 Fulcher line intensity in attached and detached divertor plasmas were roughly 1 cm and 4 cm, respectively. The fall in intensity of the H 2 Fulcher lines with distance from the divertor plates was reproduced by calculation using a neutral transport and a collisional radiative model code. Molecular assisted recombination was estimated to be as important as H +-e recombination in a detached divertor plasma.

Kubo, H.; Takenaga, H.; Sawada, K.; Nakano, T.; Kobayashi, S.; Higashijima, S.; Asakura, N.; Shimizu, K.

2005-03-01

138

JT9D engine diagnostics. Task 2: Feasibility study of measuring in-service flight loads. [747 aircraft performance  

NASA Technical Reports Server (NTRS)

The feasibility of measuring JT9D propulsion system flight inertia loads on a 747 airplane is studied. Flight loads background is discussed including the current status of 747/JT9D loads knowledge. An instrumentation and test plan is formulated for an airline-owned in-service airplane and the Boeing-owned RA001 test airplane. Technical and cost comparisons are made between these two options. An overall technical feasibility evaluation is made and a cost summary presented. Conclusions and recommendations are presented in regard to using existing inertia loads data versus conducting a flight test to measure inertia loads.

Kafka, P. G.; Skibo, M. A.; White, J. L.

1977-01-01

139

Development and achievements on the high power ECRF system in JT-60U  

NASA Astrophysics Data System (ADS)

An output power of 1.5 MW for 1 s was achieved at 110 GHz in a recent gyrotron development using the JT-60U ECRF system. It is the world's highest power oscillation for a pulse duration of at least 1 s. The achievement was enabled by, in addition to the carefully designed cavity and collector, necessary because of thermal stress, an RF shield for the adjustment bellows and a low-dielectric-loss dc break. The way the power was modulated was improved upon by controlling the anode voltage, with high modulation frequency of 5 kHz being achieved in NTM stabilization experiments. Moreover, as a developmental step to realizing a reliable ECRF system for use in future fusion experiments, a long pulse demonstration of 0.4 MW and a 30 s injection into the plasma was achieved with real time control of the anode/cathode-heater. Confirmation was made that the temperature of the cooled components had been saturated with no evidence of any damage being discovered in the waveguides and antenna without forced cooling. An innovative antenna with a relatively wide range of beam steering capabilities utilizing a linearly moving-mirror concept was also designed for use as an active cooling antenna with longer pulses in the future, e.g. for JT-60SA. The beam profile and mechanical strength analyses proved the feasibility of the antenna.

Moriyama, S.; Kobayashi, T.; Isayama, A.; Terakado, M.; Sawahata, M.; Suzuki, S.; Yokokura, K.; Shimono, M.; Hasegawa, K.; Hiranai, S.; Igarashi, K.; Sato, F.; Suzuki, T.; Wada, K.; Shinozaki, S.; Seki, M.; Kasugai, A.; Takahashi, K.; Kajiwara, K.; Sakamoto, K.; Fujii, T.

2009-08-01

140

Transient Heat Transport in Subcooled He II Associated with JT Effect  

SciTech Connect

Transient heat transport in subcooled He II has been investigated in a 1 m long rectangular channel with distributed contractions: one-closed end has a heater, while the other end is open to the He II bath. Experiments were conducted applying heat pulses and recording the temperature profile with seven Allan Bradley resistors placed along the channel. Cernox sensor was indium soldered on the heater surface to monitor the onset of film boiling. As the onset of heat pulse, the pressure at the heater surface increased because of phase change from subcooled He II to He I. Further increasing of heat pulse leads to coexistence of triple-phase, He I vapor layer, He I and subcooled He II, at the vicinity of heater surface. These effects induced instantaneous He II temperature drop along the channel, which is caused by Joule-Thomson (JT) effect. A simple model gives an approximate mechanism of pressure increase in the channel. The paper describes transient heat transport mechanism in the channel and discusses JT effect within the channel.

Maekawa, R.; Iwamoto, A.; Hamaguchi, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

2004-06-23

141

An optical design and accuracy estimation for a JT-60SA edge Thomson scattering diagnostic  

NASA Astrophysics Data System (ADS)

This paper presents the design of a collection optics used for the Thomson scattering diagnostic in JT-60SA. Good spatial resolution ( ~ 10mm) is necessary for the optics to measure detailed profiles of electron temperature (Te) and density (ne) in the plasma edge region. Six lenses forming a Petzval-like lens are employed in this design. The use of an anomalous dispersion glass material for two lenses suppresses severe chromatic aberration; two flat mirrors prevent interference with the port plug in which the collection optics is to be installed. The resultant spot radius (resolution) at the image for the peripheral region is approximately 0.2 mm. When another collection optics previously designed for core measurements is used simultaneously, the angle of laser polarization must be considered because the two collection optics are to be installed in different port-plugs accessing the vacuum vessel from the cryostat. Otherwise, the measured signal would be degraded, and the scattered spectra would be different from the expected ones. This paper evaluates the scattered spectra with relativistic effects without any approximations. This paper also provides a means to optimize the polarization angle by considering a simulated profile in JT-60SA and contributes to future devices that have limited space for collection optics.

Tojo, H.; Hatae, T.; Hamano, T.; Sakuma, T.; Itami, K.

2013-12-01

142

Evaluation of mechanical strength of the joints in JT-60 toroidal field coil conductors  

NASA Astrophysics Data System (ADS)

Toroidal field (TF) coils of JT-60 produce a toroidal field of 45 KG at a plasma axis, they have an inner bore of 3.90 m and a weight of about 80 metric tons per coil. Eighteen TF coils are located around a torus axis at regular intervals. TF coil conductors are mostly jointed by high frequency induction brazing, the rest jointed by welding. In deciding the details of the jointing procedures, the conductor size and the requested mechanical strength are mainly taken into consideration. Described are non-destructive inspection methods for the brazed joints, strength evaluation, and the inspection criteria. Ultrasonic testing method is found to be the most effective in evaluation of mechanical properties of the brazed joints especially in terms of fatigue strength. The ultrasonic inspection method and the detectability of this apparatus are described in detail, and the defects of known size are compared with the indication values and display figures. The apparatus developed for JT-60 is operated automatically also recording the inspection results. Mechanical strength of the brazed joints with initial defects is discussed.

Nishio, S.; Ohkubo, M.; Sasajima, H.

1980-04-01

143

Transient Heat Transport in Subcooled He II Associated with JT Effect  

NASA Astrophysics Data System (ADS)

Transient heat transport in subcooled He II has been investigated in a 1 m long rectangular channel with distributed contractions: one-closed end has a heater, while the other end is open to the He II bath. Experiments were conducted applying heat pulses and recording the temperature profile with seven Allan Bradley resistors placed along the channel. Cernox sensor was indium soldered on the heater surface to monitor the onset of film boiling. As the onset of heat pulse, the pressure at the heater surface increased because of phase change from subcooled He II to He I. Further increasing of heat pulse leads to coexistence of triple-phase, He I vapor layer, He I and subcooled He II, at the vicinity of heater surface. These effects induced instantaneous He II temperature drop along the channel, which is caused by Joule-Thomson (JT) effect. A simple model gives an approximate mechanism of pressure increase in the channel. The paper describes transient heat transport mechanism in the channel and discusses JT effect within the channel.

Maekawa, R.; Iwamoto, A.; Hamaguchi, S.

2004-06-01

144

DC-9 flight demonstration program with refanned JT8D engines. Volume 4: Flyover noise  

NASA Technical Reports Server (NTRS)

Flyover noise tests were conducted to determine the noise reductions achievable by modifying the engines and nacelles of DC-9-30 airplanes. The two stage fan of the JT8D-9 engine was replaced with a larger diameter, single stage fan and sound absorbing materials were incorporated in the engines and nacelles. The noise levels were determined to be 95.3 EPNdB at the sideline, 96.2 EPNdB for a full thrust takeoff, 87.5 EPNdB for takeoff with thrust cutback, and 97.4 EPNdB for landing approach. The noise reductions relative to the hardwall JT8D-9 were 8.2 EPNdB for takeoff with cutback and 8.7 EPNdB for landing. The 90 EPNdB noise contour areas were reduced by 40% for missions requiring maximum design takeoff and landing weights. For typical mission weights, the reductions were 19% for full thrust takeoff and 34% for takeoff with cutback. The 95 EPNdB contour areas were reduced by 50% for takeoff and 30% for takeoff with cutback for both missions.

1975-01-01

145

DC-9 Flight Demonstration Program with Refanned JT8D Engines. Volume 3; Performance and Analysis  

NASA Technical Reports Server (NTRS)

The JT8D-109 engine has a sea level static, standard day bare engine takeoff thrust of 73,840 N. At sea level standard day conditions the additional thrust of the JT8D-109 results in 2,040 kg additional takeoff gross weight capability for a given field length. Range loss of the DC-9 Refan airplane for long range cruise was determined. The Refan airplane demonstrated stall, static longitudinal stability, longitudinal control, longitudinal trim, minimum control speeds, and directional control characteristics similar to the DC-9-30 production airplane and complied with airworthiness requirements. Cruise, climb, and thrust reverser performance were evaluated. Structural and dynamic ground test, flight test and analytical results substantiate Refan Program requirements that the nacelle, thrust reverser hardware, and the airplane structural modifications are flightworthy and certifiable and that the airplane meets flutter speed margins. Estimated unit cost of a DC-9 Refan retrofit program is 1.338 million in mid-1975 dollars with about an equal split in cost between airframe and engine.

1975-01-01

146

JT9D performance deterioration results from a simulated aerodynamic load test  

NASA Technical Reports Server (NTRS)

The results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance are presented. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt & Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts.

Stakolich, E. G.; Stromberg, W. J.

1981-01-01

147

JT90 Ceramic Outer Air Seal System Refinement Program, Phase 2  

NASA Technical Reports Server (NTRS)

The sprayed ceramic gas turbine outer air seal system was tested in two JT9D engines to substantiate the abradability and durability of the seals. Of particular significance was that one of the tests, a 150 hour 1000 cycle endurance program at nominal JT9D operating conditions, was completed with minimal effect on the seals and received Federal Aviation Administration cognizance with respect to potential field service use by the airlines. The other engine test completed 1825 endurance cycles at severe operating conditions and no burn through or other serious defects in the structural integrity of a seal segment was observed. These test results combined with other Pratt and Whitney Aircraft engine tests substantiate the potential of the ceramic outer air seal system to attain the durability goal of 50000 hour engine operating capability. Both engine tests subjected the seals to intentional blade rubs and demonstrated good abradability with volume wear ratios greater than 100, far exceeding the design goal of 10. The improved volume wear ratio will allow the turbine tip clearance to be reduced, thereby resulting in an estimated thrust specific fuel consumption improvement of 0.3 percent.

Shiembob, L. T.

1982-01-01

148

Application of PLC to dynamic control system for liquid He cryogenic pumping facility on JT-60U NBI system  

Microsoft Academic Search

The control system of the cryogenic facility in the JT-60 NBI system has been replaced by employing the PLC (Programmable Logic Controller) and SCADA (Supervisory Control And Data Acquisition) system. The original control system was constructed about 20 years ago by specifying the DCS (Distributed Control System) computer to deal with ?400 feedback loops. Recently, troubles on this control system

A. Honda; F. Okano; K. Ooshima; N. Akino; K. Kikuchi; Y. Tanai; T. Takenouchi; S. Numazawa; Y. Ikeda

2008-01-01

149

76 FR 41144 - Airworthiness Directives; Pratt & Whitney Corp. (PW) JT9D-7R4H1 Turbofan Engines  

Federal Register 2010, 2011, 2012, 2013

...This proposed AD would require removing certain high-pressure compressor (HPC) shafts before their certified life limits...PW) JT9D-7R4H1 turbofan engines with a high-pressure compressor (HPC) shaft, part numbers (P/Ns)...

2011-07-13

150

JT-60U Thomson scattering system with multiple ruby laser and high spatial resolution for high electron temperature plasma measurement.  

National Technical Information Service (NTIS)

This article describes the design and operation of a 60 spatial channel Thomson scattering system as of 1996 with multiple ruby lasers to measure the electron temperature T(sub e) and density n(sub e) profiles of the JT-60U plasmas. The wide spectral rang...

H. Yoshida O. Naito O. Yamashita S. Kitamura T. Hatae

1996-01-01

151

The KATRIN Experiment  

NASA Astrophysics Data System (ADS)

The KArslruhe TRltium Neutrino experiment, KATRlN will determine the neutrino mass scale with a sensitivity of 0.2 e V/c2 (90%CL) via a measurement of the T2 ?-spectrum near its endpoint at 18.57 keV. The experiment consists of a windowless gaseous Tritium source, a differential- and cryopumping section, the pre- and main-spectrometer, both of the MAC-E filter type and a pixelated silicon detector. A background of less than 10 mHz and an energy resolution of 0.93 eV are necessary to achieve the desired sensitivity within 1000 days of data-taking. The experiment is currently reaching its final commissioning phase. In these proceedings, we focus on the main-spectrometer and its inner wire electrode.

Prall, Matthias

2012-08-01

152

Non-inductive current drive and profile control in JT-60U  

NASA Astrophysics Data System (ADS)

Recent studies in JT-60U to establish physics base of a steady-state tokamak reactor are presented. High fusion performance with fusion triple product nD(0)?ETi(0)=1.2×1021 keVsm-3 (equivalent QDT=0.6) has been achieved transiently in the high ?p H-mode regime. By optimizing the current and pressure profiles, a quasi steady-state high ?p H-mode with nD(0)?ETi(0)=(0.4-0.5)×1021 keVsm-3 (equivalent QDT=0.25-0.36) was maintained for up to 1.5 s. In order to maintain such high fusion performance discharges for a long time, non-inductive current drives and their capability of profile control were widely examined in the JT-60U tokamak. High-power (˜7 MW) lower hybrid current drive (LHCD) experiments were performed by using a simplified multijunction launcher. A driven current of 3.6 MA has been achieved with a current drive efficiency of (0.3-0.35)×1020 m-2A/W. Neutral beam current drive (NBCD) was also studied by using co/counter and on/off axis tangential beams (˜4 MW). The maximum driven current and the current drive efficiency were 0.55 MA and 0.06×1020 m-2A/W, respectively. Capability to control the current profile by LHCD and NBCD with a wide range of the plasma current was verified. Fully non-inductively driven discharges (Ip?1 MA) with good energy confinement (?E/?EITER89P?2.5) and a high fraction of the bootstrap current (IBS/Ip=0.6-0.7) have been obtained with NBCD and/or LHCD. These results emphasized an importance of the profile control to obtain highly integrated tokamak performance. To establish integrated basis of physics and technology for an advanced steady-state tokamak reactor and to contribute ITER activity, we continue conceptual design of a steady-state tokamak, JT-60 Super Upgrade (Ip=10 MA, Bt=6.25 T, Rp/ap=4.8/1.5 m, PNBCD=65 MW, PLHCD=20 MW with a pulse length of ?2000 s) as well.

Ushigusa, K.

1995-09-01

153

Effect of mixture composition and hardware on the performance of a single stage JT refrigerator  

NASA Astrophysics Data System (ADS)

The specific refrigeration effect that can be obtained in a single stage mixed refrigerant Joule-Thomson refrigerator is strongly dependent on the composition of mixture used. Comprehensive methods have been developed over the last two decades to determine the mixture composition that results in the highest exergy efficiency or the refrigeration produced. However, what is not well known is the relationship between the mixture composition and the hardware, which ultimately decides the performance of the refrigerator. Experiments were conducted with seven different nitrogen-hydrocarbon mixtures in a single stage JT refrigerator to understand the effect of both composition and hardware on the performance of the refrigerator, the results of which are presented in this paper.

Lakshmi Narasimhan, N.; Venkatarathnam, G.

2011-08-01

154

Electrons in the negative-ion-based NBI on JT-60 U  

SciTech Connect

The stripped electron trajectories in a large negative ion accelerator with multi-apertures and three acceleration stages, where non-uniform stray magnetic field is horizontally created, are calculated in the JT-60 negative ion source by a 3-D numerical code. The horizontal non-uniform stray field results in a significant power loss of the stripped electrons in the outmost acceleration channel on the grounded grid (GRG). The power loss in the outmost acceleration channel is more than twice higher than that in the central channel due to the weaker stray field although the total power loading on the GRG is by 25% larger than that by assuming a uniform stray field.

Kisaki, M.; Sasao, M. [School of Engineering Tohoku University, Sendai 980-8579 (Japan); Hanada, M.; Kamada, M.; Tanaka, Y.; Kobayashi, K. [Japan Atomic Energy Agency, Naka 319-0913 (Japan)

2009-03-12

155

The effect of wall materials on hydrogen recycling in JT-60  

NASA Astrophysics Data System (ADS)

A model calculation on hydrogen recycling at the wall in JT-60 has been made for three different wall materials (molybdenum, Inconel 625 and titanium carbide) for the case when the plasma is heated by neutral beam injection. It has been assumed that only charge exchange neutrals hit the wall. Values of the recycling coefficient required to keep constant plasma densities for two different flux densities 1 × 10 16 and 3 × 10 16 H/cm 2·s onto the wall have been estimated to be 0.75 and 0.92, respectively. By assuming Maxwellian energy distributions (200 and 400 eV), the recycling coefficients have been calculated as a function of time and wall temperature by taking account of particle re-emission due to backscattering, diffusion and saturation overflow. The wall temperature regions which satisfy the above criteria for 5 and 10 s discharges have been discussed for the three materials.

Sone, K.; Murakami, Y.

1984-05-01

156

Tritium release from bulk of carbon-based tiles used in JT-60U  

NASA Astrophysics Data System (ADS)

Tritium thermal release behavior from the isotropic graphite tile and the CFC tile used as the plasma facing material of JT-60U was experimentally examined. Whole tritium retained in the bulk of tile could not be released by dry gas purge at high temperature in such a period as one day. Utilization of the isotope exchange reaction using purge gas with hydrogen or humid gas was more effective to release the retained tritium. However, approximately 1% of retained tritium was not recovered by the isotope exchange reaction with dry hydrogen even though such high temperature as 1200 °C was applied. Combustion method with oxygen was required to recover all tritium left in the deeper site of the tile. It was observed that combustion of isotropic graphite tile and CFC tile became vigorous at higher temperature than 700 °C though the combustion rate was rather slow at 650 °C.

Takeishi, Toshiharu; Katayama, Kazunari; Nishikawa, Masabumi; Masaki, Kei; Miya, Naoyuki

2006-03-01

157

Fast neutron-gamma discrimination on neutron emission profile measurement on JT-60U.  

PubMed

A digital signal processing (DSP) system is applied to stilbene scintillation detectors of the multichannel neutron emission profile monitor in JT-60U. Automatic analysis of the neutron-? pulse shape discrimination is a key issue to diminish the processing time in the DSP system, and it has been applied using the two-dimensional (2D) map. Linear discriminant function is used to determine the dividing line between neutron events and ?-ray events on a 2D map. In order to verify the validity of the dividing line determination, the pulse shape discrimination quality is evaluated. As a result, the ?-ray contamination in most of the beam heating phase was negligible compared with the statistical error with 10 ms time resolution. PMID:21033854

Ishii, K; Shinohara, K; Ishikawa, M; Baba, M; Isobe, M; Okamoto, A; Kitajima, S; Sasao, M

2010-10-01

158

Steering of Multiple Beamlets in the JT-60 U Negative Ion Source  

SciTech Connect

The direct interception of D{sup -} ion beam by the acceleration grid was reduced by modifying field shaping plates (FSPs) in JT-60 negative ion sources to inject powerful neutral beams for long pulse duration of >10 s. The modified FSPs are designed by a 3D simulation code to properly steer the outermost beamlets that are deflected outward by space charge of the inward beamlets. The measured steering angles were -1.2 mrad and -6.4/-4.5 mrad in the vertical and horizontal direction, which were in agreement with the designed value calculated by the 3D simulation code. The proper steering of the outermost beamlets allowed a significant reduction of the power loading of the grounded grid. The power loading was successfully reduced to an allowable level of 5% with respect to the acceleration beam power.

Kamada, Masaki; Hanada, Masaya; Ikeda, Yoshitaka [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Grisham, Larry R. [Princeton Plasma Physics laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

2009-03-12

159

Radial Patterns of Instability and Transport in JT-60U Internal Transport Barrier Discharges  

SciTech Connect

One class of internal transport barrier discharges in the JT-60U tokamak is characterized by two relatively flatter regions of the pressure separated by a region with very large pressure gradient. Linear growth rates for toroidal drift-type modes are calculated for discharges in this class, without and with sheared E x B rotation effects. For cases with fully-developed barriers, the results with rotation are consistent with a picture in which the radial electric field generated in part by the steep pressure gradient causes local stabilization, and thus reduction of the local anomalous transport, which allows the steep pressure gradient to persist. If rotation is omitted from the calculation for these cases, or if rotation is included for cases without barriers or with partially developed barriers, the unstable region spreads into the steep pressure gradient region.

G. Rewoldt; K.W. Hill; R. Nazikian; W.M. Tang; H Shirai; Y. Sakamoto; Y. Kishimoto; S.Ide; and T. Fujita

2001-02-27

160

Behaviour of light impurities in beam-heated jt-60 plasmas with hot graphite walls  

NASA Astrophysics Data System (ADS)

The behaviour of light impurities in beam-heated JT-60 plasmas, after changing the limiter and armour tile material from TiC coated molybdenum and inconel to graphite, is discussed. In limiter discharges with high power neutral injection of greater than 12 MW and small gas puff rate, it is generally observed that the influx of carbon increases during the neutral beam phase. This phenomenon is delayed when the base temperature of the vacuum vessel is low. If the heat load to the wall is taken to be 6 MW/m 2 then it is estimated that the increased carbon influx occurs at a wall temperature of 800 K. This temperature coincides with that for maximum chemical sputtering. The strongly rising influx of carbon is therefore attributed to chemical sputtering.

JT-60 Team; Nishino, N.; Kubo, H.; Sakasai, A.; Koide, Y.; Sugie, T.; Takeuchi, T.

1989-04-01

161

Contribution of Ne ions to radiation enhancement in JT-60U divertor plasmas  

NASA Astrophysics Data System (ADS)

The emission spectra from Ne seeded divertor plasmas of JT-60U are measured by an absolutely calibrated vacuum ultraviolet spectrometer and analyzed with a collisional-radiative model. The radiative power of Ne ions from the inner divertor plasma in the detached phase contributes 55% of the total radiative power while that in the attached phase contributes 34% even at a similar Ne seeding rate. From an analysis of the intensity ratios of Ne VIII spectral lines, it is found that volume recombination of Ne IX to Ne VIII occurs more frequently in the detached plasma, enhancing Ne VIII density. This is one of the leading processes that enhances the radiative power from highly charged Ne ions in the detached plasma. For interpretation of color in Fig. 6, the reader is referred to the web version of this article.

Nakano, T.; Asakura, N.; Kubo, H.

2013-07-01

162

Long pulse production of high current D(-) ion beams in the JT-60 negative ion source.  

PubMed

The first long pulse production of high power D(-) ion beams has been demonstrated in the JT-60 U negative ion sources, each of which was designed to produce 22 A, 500 keV D(-) ion beams. Voltage holding capability and the grid power loading were examined for long pulse production of high power D(-) ion beams. From the correlation between voltage holding and the light intensity of cathodoluminescence from the Fiber Reinforced Plastic insulators, the acceleration voltage for stable voltage holding capability was found to be less than 320-340 kV where the light was sufficiently suppressed. By tuning the extraction voltage, the grid power loadings in the ion sources were decreased to the allowable levels for long pulse injection without a significant reduction of the beam power. After tuning the acceleration and extraction voltages, D(-) ion beams of 12.5 and 9.8 A were produced at 340 keV with cesium seeding at a rate of approximately 14 microg/s into the ion sources. The pulse duration of these D(-) ion beams was extended step by step, and then was successfully extended up to 18 s without degradation of the negative ion production. The D(-) ion beams were neutralized to yield 3.6 MW D(0) beams by a gas cell, and then injected into the JT-60 U plasma. Further, a slight reduction of D(-) ion beam power allowed the longer injection duration of 21 s at a D(0) beam power of 3.2 MW. The success in the long pulse production of a high power D(-) ion beam shows that negative ion beams can be produced during a few tens of seconds without degradations of negative ion production and the voltage holding in a large Cs-seeded negative ion source. PMID:18315140

Hanada, M; Kamada, M; Akino, N; Ebisawa, N; Honda, A; Kawai, M; Kazawa, M; Kikuchi, K; Komata, M; Mogaki, K; Noto, K; Ohshima, K; Takenouchi, T; Tanai, Y; Usui, K; Yamazaki, H; Ikeda, Y; Grisham, L R

2008-02-01

163

75 FR 50942 - Airworthiness Directives; Pratt & Whitney JT8D-7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A...  

Federal Register 2010, 2011, 2012, 2013

...JT8D-7, -7A, -7B, -9, - 9A, -11, -15, -15A, -17, -17A, -17R, and -17AR...7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR...JT8D-7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and...

2010-08-18

164

3-Methoxy-2-methyl-carbazole-1,4-quinone, carbazomycins D and F from Streptomyces sp. CMU-JT005.  

PubMed

3-Methoxy-2-methyl-carbazole-1,4-quinone (1) together with carbazomycins D (2) and F (3) were isolated from the crude extract of Streptomyces CMU-JT005, an actinomycete with nematicidal activity. 3-Methoxy-2-methyl-carbazole-1,4-quinone is reported here for the first time from nature. In this paper, we describe the isolation and structure elucidation of the compounds together with the characterization of the Streptomyces strain CMU-JT005. PMID:21668483

Ruanpanun, Pornthip; Dame, Zerihun Teklemariam; Laatsch, Hartmut; Lumyong, Saisamorn

2011-09-01

165

Upregulation of FGFR1 expression is associated with parathyroid carcinogenesis in HPT-JT syndrome due to an HRPT2 splicing mutation.  

PubMed

Mutations of the HRPT2 gene, which are responsible for hyperparathyroidism-jaw tumor (HPT-JT) syndrome, have been implicated in the development of a high proportion of parathyroid carcinomas. The aim of this study was to investigate differences in expression of the most important genes connected with parathyroid carcinoma between HPT-JT syndrome due to an HRPT2 splicing mutation, normal parathyroid tissue and sporadic parathyroid adenoma. Total RNAs were extracted from parathyroid carcinoma in HPT-JT syndrome harbouring HRPT2 splicing mutation or sporadic parathyroid adenoma and normal parathyroid gland, and subjected to Illumina DASL-based gene expression assay. Unsupervised hierarchical clustering analysis was used to compare gene expression in HPT-JT syndrome, sporadic parathyroid adenoma and normal parathyroid glands. We identified differentially regulated genes in HPT-JT syndrome and sporadic parathyroid adenoma relative to normal parathyroid glands using a combination of Welch's t-test and fold-change analysis. Quantitative PCR, RT-PCR and IHC were used for validation. Sixteen genes differentially regulated in the parathyroid carcinoma were associated with signal pathways, MAPK, regulation of actin cytoskeleton, prostate cancer and apoptosis. FGFR1 expression was confirmed to be significantly upregulated by validation experiments. Our gene expression profiling experiments suggest that upregulated FGFR1 expression appears to be associated with parathyroid carcinoma in HPT-JT syndrome due to an HRPT2 splicing mutation. PMID:24889687

Lee, Ji-Young; Kim, Su Yeon; Mo, Eun-Yeong; Kim, Eun-Sook; Han, Je-Ho; Maeng, Lee-So; Lee, An-Hee; Eun, Jung Woo; Nam, Suk Woo; Moon, Sung-Dae

2014-08-01

166

Improvement of voltage holding capability in the 500 keV negative ion source for JT-60SA  

SciTech Connect

Voltage holding capability of JT-60 negative ion source that has a large electrostatic negative ion accelerator with 45 cmx1.1 m acceleration grids was experimentally examined and improved to realize 500 keV, 22 A, and 100 s D{sup -} ion beams for JT-60 Super Advanced. The gap lengths in the acceleration stages were extended to reduce electric fields in a gap between the large grids and at the corner of the support flanges from the original 4-5 to 3-4 kV/mm. As a result, the voltage holding capability without beam acceleration has been successfully improved from 400 to 500 kV. The pulse duration to hold 500 kV reached 40 s of the power supply limitation.

Tanaka, Y.; Hanada, M.; Kojima, A.; Akino, N.; Shimizu, T.; Ohshima, K.; Inoue, T.; Watanabe, K.; Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Tobari, H. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Collaboration: JT-60 NBI Group

2010-02-15

167

Finite element-integral simulation of static and flight fan noise radiation from the JT15D turbofan engine  

NASA Technical Reports Server (NTRS)

An iterative finite element integral technique is used to predict the sound field radiated from the JT15D turbofan inlet. The sound field is divided into two regions: the sound field within and near the inlet which is computed using the finite element method and the radiation field beyond the inlet which is calculated using an integral solution technique. The velocity potential formulation of the acoustic wave equation was employed in the program. For some single mode JT15D data, the theory and experiment are in good agreement for the far field radiation pattern as well as suppressor attenuation. Also, the computer program is used to simulate flight effects that cannot be performed on a ground static test stand.

Baumeister, K. J.; Horowitz, S. J.

1982-01-01

168

Comparison of several inflow control devices for flight simulation of fan tone noise using a JT15D-1 engine  

NASA Technical Reports Server (NTRS)

The paper describes the tests of four devices intended to reduce inflow disturbances and turbulences using a JT15D-1 turbofan engine. The tests were made to simulate the in-flight fan tone noise; the inflow control devices (ICD's) consisted of honeycomb/screen structures mounted over the engine inlet. The ICD's ranged from 1.6 to 4 fan diameters in size, and were made with several fabrication methods. All the ICD's significantly reduced the BPF tone in the far-field directivity patterns, but the smallest ICD's introduced propagating modes which could be recognized by additional lobes in the patterns. The JT15D-1 engine had a tone source which generated a strong propagating mode at fan speeds corresponding to 'approach' power and higher. Data from a typical transducer showed that the unsteady inflow distortion modes were eliminated or reduced when either of the ICD's was installed.

Mcardie, J. G.; Jones, W. L.; Heidelberg, L. J.; Homyak, L.

1980-01-01

169

Internal transport barrier on q=3 surface and poloidal plasma spin up in JT-60U high-betap discharges  

Microsoft Academic Search

Spontaneous formation of an internal transport barrier was observed associated with improved confinement in the high-betap discharges in the JT-60U tokamak. The radial location of the transport barrier was found to be on the q=3 surface. A fast magnetohydrodynamic event localized at the transport barrier triggered the subsequent formation of an edge transport barrier that resulted in the further confinement

Y. Koide; M. Kikuchi; M. Mori; S. Tsuji; S. Ishida; N. Asakura; Y. Kamada; T. Nishitani; Y. Kawano; T. Hatae; T. Fujita; T. Fukuda; A. Sakasai; T. Kondoh; R. Yoshino; Y. Neyatani

1994-01-01

170

Kinetic effect of thermal force on impurity transport: Simulation of JT-60SA divertor with integrated divertor code SONIC  

NASA Astrophysics Data System (ADS)

Using an impurity Monte-Carlo code, IMPMC, the kinetic effect of thermal force on the He transport is investigated for JT-60SA detached plasmas. Without the recycling process, the kinetic effect of the thermal force is found to increase the He density in the divertor region by a factor of ˜2, compared with the conventional (fluid) evaluation. However, the kinetic effect is masked by the recycling at the target plates.

Shimizu, K.; Takizuka, T.; Kawashima, H.

2009-06-01

171

Fast data acquisition system based on digital oscilloscopes for fluctuation measurements in a long pulse JT-60U tokamak plasma  

Microsoft Academic Search

We have developed a new data acquisition (DAQ) system with fast sampling rate for fluctuation measurements in a long pulse JT-60U tokamak plasma. This system is based on a powerful digital oscilloscope, which has a large acquisition memory up to 50?Mwords\\/ch, 1?MHz sampling rate and 16?bits high resolution AD convertors. The system is composed of plural digital oscilloscopes and mass

G. Matsunaga; M. Takechi; K. Toi

2007-01-01

172

Absolute calibration of the JT-60U neutron monitor using a 252Cf neutron source (abstract)a)  

Microsoft Academic Search

Absolutely calibrated measurements of the neutron yield are important for the evaluation of the plasma performance such as the fusion gain Q in D-D operating tokamaks. The time-resolved neutron yield is measured with 235U and 238U fission chambers and 3He proportional counters in the JT-60U tokamak. The insitu calibration was performed by moving the 252Cf neutron source toroidally through the

T. Nishitani; H. Takeuchi; T. Kondoh; T. Itoh; M. Kuriyama; Y. Ikeda; T. Iguchi; Cris W. Barnes

1992-01-01

173

Absolute calibration of the JT-60U neutron monitor using a sup 252 Cf neutron source (abstract)  

Microsoft Academic Search

Absolutely calibrated measurements of the neutron yield are important for the evaluation of the plasma performance such as the fusion gain {ital Q} in D-D operating tokamaks. The time-resolved neutron yield is measured with ²³⁵U and ²³⁸U fission chambers and ³He proportional counters in the JT-60U tokamak. The {ital in} {ital situ} calibration was performed by moving the ²⁵²Cf neutron

T. Nishitani; H. Takeuchi; T. Kondoh; T. Itoh; M. Kuriyama; Y. Ikeda; T. Iguchi; C. W. Barnes

1992-01-01

174

Development of Fast Measurement System of Neutron Emission Profile Using a Digital Signal Processing Technique in JT-60U  

SciTech Connect

Neutron emission profiles are routinely measured in JT-60U Tokamak. Stinbene neuron detectors (SNDs), which combine a Stilbene organic crystal scintillation detector (Stilbene detector) with an analog neutron-gamma pulse shape discrimination (PSD) circuit, have been used to measure neutron flux efficiently. Although the SND has many advantages as a neutron detector, the maximum count rate is limited up to {approx}1x 10{sup 5} counts/s due to the dead time of the analog PSD circuit. To overcome this issue, a digital signal processing (DSP) system using a Flash-ADC has been developed. In this system, anode signals from the photomultiplier of the Stilbene detector are fed to the Flash ADC and digitized. Then, the PSD between neutrons and gamma-rays are performed using software. The photomultiplier tube is also modified to suppress and correct gain fluctuation of the photomultiplier. The DSP system has been installed in the center channel of the vertical neutron collimator system in JT-60U and applied to measurements of neutron flux in JT-60U experiments. Neutron flux are successfully measured with count rate up to {approx}1x 10{sup 6} counts/s without the effect of pile up of detected pulses. The performance of the DSP system as a neutron detector is demonstrated.

Ishikawa, M.; Shinohara, K. [Japan Atomic Energy Agency, Mukoyama 801-1 Naka, Ibaraki 311-0193 (Japan); Itoga, T.; Okuji, T.; Nakhostin, M.; Baba, M.; Nishitani, T. [Cyclotron and Radioisotope Center, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan)

2008-03-12

175

A 727 airplane center duct inlet low speed performance confirmation model test for refanned JT8D engines, phase 2  

NASA Technical Reports Server (NTRS)

The results from testing of a 0.3 scale model center duct inlet (S duct) for the Pratt and Whitney Aircraft JT8D-100 engines are presented. The objective of this test was to demonstrate that the required airflow of the JT8D-100 engine (480 lb/sec as compared to 334 lb/sec for JT8D-15) can be achieved with minimum modifications to the existing 727 airplane structure at acceptable levels of total pressure recovery and distortion. Steady-state pressure recovery, steady-state pressure distortion, and dynamic pressure measurements were taken at the engine face station. Surface static pressure measurements were taken along the duct. Test results indicated that the required airflow was achieved with acceptable pressure recovery (comparable to the current 727-200 S duct). Inlet inflow angle variation within the 727 airplane operating regime (minus 5 to 5 degrees) had no effect on the inlet performance. Pressure distortion at static and forward speed at takeoff airflow conditions are within P and WA limits for the Phase II duct when equipped with vortex generators. Static crosswind operation between 10 knots and 25 knots appears feasible at full takeoff power.

Kaldschmidt, G.; Syltebo, B. E.; Ting, C. T.

1973-01-01

176

Introduction of a Saturated Bath in Vincenta Models: Application to the Cryogenic System for JT-60SA Tokamak  

NASA Astrophysics Data System (ADS)

The CEA is involved in large helium refrigeration applied to the future experimental fusion reactors (e.g. ITER or JT-60SA). Pulsed operation of such machines results in heat load variations which the refrigerators have to cope with. One solution to smooth pulsed loads is to use a large thermal buffer, and in the case of JT-60SA cryogenic system, a saturated thermal bath is one of the investigated solutions. A 1D thermo hydraulic model describing the cooling loop associated with TF (Toroidal Field) coils and TF casing has been developed using Vincenta code to calculate the heat load arriving to the buffer (saturated bath). However, the liquid helium buffer itself and its coupling with the primary loop was not modelized. This paper shows results obtained using the existing functionalities in Vincenta code to model a saturated bath. For very large bath volumes, bath temperature remains almost steady and the power removed is equal to those previously calculated. On the other side, for smaller buffer volumes (e.g. JT-60SA scheme), it has been found that the increase of temperature fluctuations does not vary proportionally with the decrease of the buffer volume.

Rousset, B.; Roussel, P.; Michel, F.; Hitz, D.

2010-04-01

177

Retention of Hydrogen Isotopes in Divertor Tiles Used in JT-60U  

SciTech Connect

Retention characteristics of deuterium and hydrogen retained in graphite tiles placed in the divertor region of JT-60U were investigated by thermal desorption spectroscopy (TDS). The deuterium retained in the near surface of all graphite tiles was mostly replaced by hydrogen due to exposure to hydrogen plasma at the final stage operations, resulting in main deuterium retention in the deeper region. The dominant species desorbed from the divertor tiles were H{sub 2}, HD, D{sub 2} and CH{sub 4}. The smallest retention of hydrogen isotopes (H+D) was observed in the outer divertor tile which was eroded with maximum of 20 {mu}m depth. The amount of H+D retained in the inner divertor tiles covered by the re-deposited layers increased with the thickness of the re-deposited layers. Hydrogen isotopes concentration ((H+D)/C) in the re-deposited layers was {approx}0.02, which was much smaller than those observed in JET and other devices.

Hirohata, Y. [Hokkaido University (Japan); Shibahara, T. [Nagoya University (Japan); Tanabe, T. [Nagoya University (Japan); Oya, Y. [University of Tokyo (Japan); Arai, T. [Japan Atomic Energy Research Institute (Japan); Gotoh, Y. [Japan Atomic Energy Research Institute (Japan); Masaki, K. [Japan Atomic Energy Research Institute (Japan); Yagyu, J. [Japan Atomic Energy Research Institute (Japan); Oyaidzu, M. [Shizuoka University (Japan); Okuno, K. [Shizuoka University (Japan); Nishikawa, M. [Kyusyu University (Japan); Miya, N. [Japan Atomic Energy Research Institute (Japan)

2005-07-15

178

Removal of the deposition on JT-60 tile by nano-sec pulsed-laser irradiation  

NASA Astrophysics Data System (ADS)

To clarify the property of tritium removal from carbon codeposition by using pulsed-laser induced desorption, hydrogen removal from co-deposits on JT-60 divertor tile using a fourth-harmonic emission (266 nm) of a nano-sec Nd:YAG laser was demonstrated. The threshold laser fluence for ablation was ˜0.3 J/cm 2, which was slightly higher compared to that of the pico-sec laser irradiation. The energy absorption coefficient for the nano-sec laser, which was obtained by fitting the removal rate by so-called Beer's law, was larger than the pico-sec laser. Since the time constant of thermal wave propagation into the target is of the order of nano-sec, such differences between nano- and pico-sec lasers could be attributed to thermal effects. The ablation threshold of the deposited layer was lower than that of a pure graphite, which could be attributed to the difference of thermal conductivity between deposited layer and pure graphite. The removal rate of the nano-sec laser was higher than that of pico-sec laser in the fluence range of >˜0.5 J/cm 2. On the other hand, the production ratio [hydrocarbon species]/[H 2] continuously increased with the laser fluence, and no significant ionization of carbon was observed in this fluence range. This indicated that the fluence range in this study was "weak"-ablation range, which was still not sufficient to minimize the hydrocarbon production.

Sugiyama, K.; Sakawa, Y.; Tanabe, T.; Watanabe, D.; Shibahara, T.; Masaki, K.

2010-10-01

179

Investigation of performance deterioration of the CF6/JT9D high bypass ratio turbofan engines  

NASA Technical Reports Server (NTRS)

The extent and magnitude of performance deterioration of the Pratt and Whitney JT9D, and the General Electric CF6 engine models is presented. Overall engine and contributing module performance deterioration with respect to flight cycles and/or time are analyzed. The overall engine performance deterioration analyses are based on data obtained from historical records, special engine tests, and tests for specific effects. Hardware inspection data from overhaul shops and special module tests are the basis for the modular performance deterioration data used in the analyses. Various damage mechanisms such as seal rubs, erosion, surface roughness and thermal distortion, and how they contribute to performance deterioration are included in the modular analyses. Results indicate that early performance deterioration occurring within the first few flights of these engines is less than 1 percent in cruise specific fuel consumption (SFC), that it is event oriented, and that it is the result of increased blade tip clearances. This performance deterioration gradually increases to about 2.5 to 3.0 percent (including the initial short term deterioration) after 2500 to 3000 flights where increased blade tip clearances, airfoil quality degradation, and thermal distortion are the contributing causes.

Ziemianski, J. A.

1981-01-01

180

Titanium carbide coating on inconel 625 liner for JT-60 BY HCD-ARE  

NASA Astrophysics Data System (ADS)

The HCD-ARE (activated reactive evaporation using a hollow cathode discharge) method was applied to coat the TiC layer, being a low Z material, on the full-size Inconel 625 liner for JT-60 with the aim of ascertaining its capability of mass-productive coating and further of supplying suitable products which satisfy the properties required from fusion devices. The film was deposited at the substrate temperature of 500°C using an in-line evaporation system consisting of four vacuum chambers. The characteristics of the films are nearly equal to each other over the whole area of the sample liner. The deposited films of about 20 ?m thick and a nearly stoichiometric composition show a preferred orientation in the (220) direction and the value of their line half-width is 0.23 0.26 deg. The lattice constants are nearly equal to those of the bulk crystal. By XPS observation the chemical shifts in C1s and Ti 2p{sol3}/{2} binding of the TiC film were about -3 and +1 eV which are nearly equal to those of the single crystal, respectively. As a result of convenient valuation of the durability of coatings, TiC film exhibiting a strong adhesion and an adequate durability was obtained by the HCD-ARE method.

Inagawa, K.; Watanabe, K.; Tanaka, I.; Itoh, A.; Abe, T.; Murakami, Y.; Mizoguchi, T.; Itou, Y.

1984-12-01

181

Twenty-channel grating polychromator diagnostic system for electron cyclotron emission measurement in JT-60  

SciTech Connect

A twenty-channel grating polychromator diagnostic system has been built to measure the temporal evolution of local electron temperatures in JT-60. A cross Czerny--Turner diffraction grating spectrometer is utilized for the measurement of second-harmonic electron cyclotron emission with extraordinary modes in the range 85--300 GHz, in which a grating plate grooved on both faces with different grating periods is applied effectively to yield a wide coverage for the toroidal fields. The grating angle is automatically set up by control of a stepping motor according to the relation of the grating equation. The diffracted light is detected by 20 indium-antimonide hot-electron bolometers cooled at 4.3 K in a modified Solvay cycle cryogenic refrigerator. A typical resolving power of the instrument was measured to be {lambda}/{Delta}{lambda}{approximately}130, providing a spatial resolution of 2.3 cm at the plasma center. The transmission line over {approximately}38 m long is composed of oversized {ital S}-band waveguides. The total transmissivity of this system is estimated to be {approximately}0.01.

Ishida, S.; Nagashima, A.; Sato, M.; Isei, N.; Matoba, T. (Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Naka-gun, Naka-machi, Ibaraki-ken (Japan))

1990-10-01

182

Energetic Particle Experiments in JT-60U and Their Implications for a Fusion Reactor  

SciTech Connect

Energetic particle experiments in JT-60U are summarized, mainly covering ripple loss and Alfven eigenmodes (AE modes). Significant loss was observed for 85 keV neutral beam injected (NBI) ions and fusion-produced tritons as toroidal field ripple at the plasma surface increased, especially in a reversed shear plasma. Measurement of hot spots on the first wall due to ripple loss confirmed agreement with code predictions, validating the modeling incorporated in an orbit-following Monte Carlo code. A variety of AE modes were destabilized in ion cyclotron range of frequencies (ICRF) minority heating and negative-ion-based NBI (N-NBI) heating. Most of the observed modes are gap modes identified to be toroidicity-induced, ellipticity-induced, and triangularity-induced AE modes. An interesting finding is pulsating modes accompanying frequency sweep, which were destabilized by N-NBI and sometimes induced a beam ion loss of up to 25%. Also presented are energetic particle issues in auxiliary heating with ICRF and N-NBI.

Tobita, K.; Kusama, Y.; Shinohara, K.; Nishitani, T.; Kimura, H.; Kramer, G.J.; Nemoto, M.; Kondoh, T.; Oikawa, T.; Morioka, A.; Hamamatsu, K.; Wang, S.; Takeji, S.; Takechi, M.; Ishikawa, M.; Tani, K.; Saigusa, M.; Ozeki, T. [Japan Atomic Energy Research Institute (Japan)

2002-09-15

183

Density fluctuation measurement using motional Stark effect optics in JT-60U  

NASA Astrophysics Data System (ADS)

The multichannel motional Stark effect (MSE) diagnostic system in JT-60U has been upgraded to measure density fluctuation profile. A 16-channel fast-sampling digitizer has been added in order to measure photomultiplier-tube signals at measurement frequency of 0.5-1 MHz. The new system works as a MSE and beam emission spectroscopy diagnostic. Spatially resolved electron density fluctuation profile measurement in various operation regimes is presented. In the core plasma, density fluctuation induced by rotation of tearing mode islands was observed. Temporal evolution of the fluctuation frequency agrees with that measured by Mirnov coils (poloidal and toroidal mode numbers: 2 and 1, respectively). The phases of the fluctuations on either side of the q=2 surface are inverted, which is consistent with electron cyclotron emission. These measurements show that the density fluctuation is caused by a rotating magnetic island structure induced by the tearing mode. In the scrape-off layer of a H-mode plasma with edge-localized-mode (ELM), i. e., ELMy H-mode outward propagation of strong intermittent emission corresponding to ELM crash was also observed. The propagation velocity is 0.69-2.2 km/s along the MSE measurement points, the time lag and distance between adjacent channels being 67+/-35 ?s and 70 mm, respectively.

Suzuki, T.; Fujita, T.; Oyama, N.; Isayama, A.; Matsunaga, G.; Oikawa, T.; Asakura, N.; Takechi, M.

2006-10-01

184

Beam acceleration test in negative-ion based NBI system for JT-60U  

NASA Astrophysics Data System (ADS)

Beam extraction and acceleration test in the Negative Ion Based Neutral Beam Injector for JT-60U has been started using one ion source that is designed to produce a 500 keV, 22 A D- ion beam. Deuterium negative ions are produced in a cesium-seeded semi-cylindrical plasma generator and accelerated by a multi-aperture three-stage electrostatic accelerator. In the preliminary experiment of beam acceleration, the D- ion beam of 13.5 A was successfully accelerated to 400 keV for a pulse duration of 0.12 s. The negative ion beam power was 5.4 MW. The operating gas pressure in the plasma generator was as low as 0.22 Pa. The highest energy beam of 460 keV, 2.4 A, 0.44 s was also obtained. The ratio of extracted electron current to extracted negative ion current is estimated Ie/ID-<1. It was confirmed that the electron leak from the extractor to the accelerator is suppressed efficiently by the effects of biassing, electron trapping gap and magnetic field.

Watanabe, K.; Akino, N.; Araki, M.; Ebisawa, N.; Fujiwara, Y.; Hanada, M.; Honda, A.; Inoue, T.; Itoh, T.; Kawai, M.; Kazawa, M.; Koizumi, J.; Kuriyama, M.; Miyamoto, K.; Miyamoto, N.; Mogaki, K.; Nagase, A.; Ohara, Y.; Ohga, T.; Okumura, Y.; Oohara, H.; Ohshima, K.; Satoh, F.; Takahashi, S.; Takenouchi, T.; Usami, H.; Usui, K.; Yamamoto, M.; Yamazaki, T.

1996-07-01

185

Beam acceleration test in negative-ion based NBI system for JT-60U  

SciTech Connect

Beam extraction and acceleration test in the Negative Ion Based Neutral Beam Injector for JT-60U has been started using one ion source that is designed to produce a 500 keV, 22 A D{sup {minus}} ion beam. Deuterium negative ions are produced in a cesium-seeded semi-cylindrical plasma generator and accelerated by a multi-aperture three-stage electrostatic accelerator. In the preliminary experiment of beam acceleration, the D{sup {minus}} ion beam of 13.5 A was successfully accelerated to 400 keV for a pulse duration of 0.12 s. The negative ion beam power was 5.4 MW. The operating gas pressure in the plasma generator was as low as 0.22 Pa. The highest energy beam of 460 keV, 2.4 A, 0.44 s was also obtained. The ratio of extracted electron current to extracted negative ion current is estimated Ie/I{sub D{sup {minus}}}{lt}1. It was confirmed that the electron leak from the extractor to the accelerator is suppressed efficiently by the effects of biassing, electron trapping gap and magnetic field. {copyright} {ital 1996 American Institute of Physics.}

Watanabe, K.; Akino, N.; Araki, M.; Ebisawa, N.; Fujiwara, Y.; Hanada, M.; Honda, A.; Inoue, T.; Itoh, T.; Kawai, M.; Kazawa, M.; Koizumi, J.; Kuriyama, M.; Miyamoto, K.; Miyamoto, N.; Mogaki, K.; Nagase, A.; Ohara, Y.; Ohga, T.; Okumura, Y.; Oohara, H.; Ohshima, K.; Satoh, F.; Takahashi, S.; Takenouchi, T.; Usami, H.; Usui, K.; Yamamoto, M.; Yamazaki, T. [Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki-ken, 311-01 (Japan)

1996-07-01

186

Progress of Negative Ion Source Improvement in N-NBI for JT-60U  

SciTech Connect

The negative-ion based neutral beam injection system developed by JAERI for JT-60U has been intended to generate a 500 keV and 10 MW beam for 10 seconds with two ion sources. Technical efforts to decrease heat loads on the accelerator grids, to improve non-uniformity of the source plasma, to increase voltage holding of the accelerator, and to optimize the operational parameters have been conducted intensively. A step-down control of the filament voltage was very effective to keep the acceleration current constant during the pulse duration. To suppress degradation of voltage holding of the accelerator, protection spark gaps of {approx}178 kV for each stage, its gap length is 73 mm, were confirmed to be effective.As results of these improvements, as of June 2002, the maximum injection power has reached 6.2 MW, and a pulse length has attained 10 seconds of the design value with a 2.6 MW beam.

Kawai, M. [Naka Fusion Research Establishment (Japan); Akino, N. [Naka Fusion Research Establishment (Japan); Ebisawa, N. [Naka Fusion Research Establishment (Japan); Grisham, L. [Princeton Plasma Physics Laboratory (United States); Hanada, M. [Naka Fusion Research Establishment (Japan); Honda, A. [Naka Fusion Research Establishment (Japan); Inoue, T. [Naka Fusion Research Establishment (Japan); Kazawa, M. [Naka Fusion Research Establishment (Japan); Kikuchi, K. [Naka Fusion Research Establishment (Japan); Kuriyama, M. [Japan Atomic Energy Research Institute (Japan); Kusanagi, N. [Naka Fusion Research Establishment (Japan); Mogaki, K. [Naka Fusion Research Establishment (Japan); Noto, K. [Naka Fusion Research Establishment (Japan); Ohga, T. [Naka Fusion Research Establishment (Japan); Ooshima, K. [Naka Fusion Research Establishment (Japan); Tanai, Y. [Naka Fusion Research Establishment (Japan); Umeda, N. [Naka Fusion Research Establishment (Japan); Usui, K. [Naka Fusion Research Establishment (Japan); Yamamoto, T. [Naka Fusion Research Establishment (Japan); Yamazaki, H. [Naka Fusion Research Establishment (Japan); Watanabe, K. [Naka Fusion Research Establishment (Japan)

2003-09-15

187

Dependence of heat transport on toroidal rotation in conventional H-modes in JT-60U  

NASA Astrophysics Data System (ADS)

The relation between heat transport in the plasma core and the toroidal rotation profile was examined in conventional ELMy H-mode plasmas in JT-60U. Heat transport in the plasma core is not strongly influenced locally by toroidal rotation. The large increase in heat conduction imposes a resilient profile of ion temperature, under which the local effect of the toroidal rotation profile on scale length of the ion temperature gradient is very weak. Energy confinement improvement is observed with toroidal rotation which increases in the co-direction with respect to the plasma current. In this case, the increase in the ion temperature in both the plasma core and the pedestal region is observed. However, heat transport in the plasma core varies while maintaining self-similar temperature profiles as the toroidal rotation profile is varied. Pressure at the H-mode pedestal becomes slightly larger with the toroidal rotation in the co-direction. Thus, energy confinement enhanced with co-toroidal rotation is determined by increased pedestal height and reduced transport brought on by profile resilience. When pedestal temperature was fixed between the cases of co- and counter-NBI by adjusting the plasma density, identical temperature profiles were obtained in spite of totally different toroidal rotation profiles.

Urano, H.; Takenaga, H.; Fujita, T.; Kamada, Y.; Koide, Y.; Oyama, N.; Yoshida, M.; JT-60 Team

2008-08-01

188

Fusion gamma-ray measurements for D-3He experiments at JT-60U  

NASA Astrophysics Data System (ADS)

Fusion gamma rays were measured in D-3He experiments using negative ion-based neutral beam injection (N-NBI) in reverse shear plasmas of the JT-60 tokamak. 3He gas was puffed at plasma initiation and just before N-NB injection. The D-3He reaction produces 3.6 MeV alphas and 14.7 MeV protons, but there is also a small branch which provides 5Li and 16.7 MeV gamma rays. The total D-3He reaction rate can be evaluated from measurement of gamma rays of the 3He (d,?) 5Li reactions using a 3 in. diam by 3 in. long Bi4Ge3O12 scintillator. The gamma-ray detector was located 17 m below the plasma center and measured the gamma-rays in a vertical line of sight. The detector was mounted inside a heavy collimator with polyethylene and lead shielding. The floor penetration, a 4×8 cm2 hole, was used as a precollimator. Energy calibration of the detector was done with photopeaks for neutron capture gamma rays from the structural materials in D-D discharges. The detection efficiency was calculated with Monte Carlo code MCNP-4B for 16.7 MeV gammas. The pulse height analysis of the gamma rays resulted in the D-3He fusion power of 110+/-30 kW in this experiment.

Nishitani, T.; Tobita, K.; Kusama, Y.; Shibata, Y.

2001-01-01

189

Pressure transfer function of a JT15D nozzle due to acoustic and convected entropy fluctuations  

NASA Technical Reports Server (NTRS)

An acoustic transmission matrix analysis of sound propagation in a variable area duct with and without flow is extended to include convected entropy fluctuations. The boundary conditions used in the analysis are a transfer function relating entropy and pressure at the nozzle inlet and the nozzle exit impedance. The nozzle pressure transfer function calculated is compared with JT15D turbofan engine nozzle data. The one dimensional theory for sound propagation in a variable area nozzle with flow but without convected entropy is good at the low engine speeds where the nozzle exit Mach number is low (M=0.2) and the duct exit impedance model is good. The effect of convected entropy appears to be so negligible that it is obscured by the inaccuracy of the nozzle exit impedance model, the lack of information on the magnitude of the convected entropy and its phase relationship with the pressure, and the scatter in the data. An improved duct exit impedance model is required at the higher engine speeds where the nozzle exit Mach number is high (M=0.56) and at low frequencies (below 120 Hz).

Miles, J. H.

1982-01-01

190

Preliminary core-engine noise abatement experimental results of a fluid injection nozzle on a JT-15D turbofan engine  

NASA Technical Reports Server (NTRS)

Jet noise, as induced by shear stress, in an jet exhaust is investigated. Experiments were performed on a JT-15D fan jet to verify the inward momentum stress reduction concept. The experiments involved making fan air flow convergently around the high velocity core jet with a small angle. Ring airfoils were used as flow separators for the minimization of the thrust loss. Jet exhaust noise reduction of ll db at 30 deg from the jet axis was recorded and 8 db integrated overall noise reduction over a hemisphere was measured with only 4.6% thrust loss, or 152 db/percent thrust loss.

Cheng, D. Y.; Wang, P.

1975-01-01

191

Deuterium depth profiling in graphite tiles not exposed to hydrogen discharges before air ventilation of JT-60U  

Microsoft Academic Search

Depth profiles of deuterium trapped in graphite tiles not exposed to hydrogen discharges just before air ventilation of JT-60U were determined based on the D(3He,p)4He resonant nuclear reaction analysis. The samples were taken from the W-shaped divertor. The maximum depth of analysis is about 1.4×1024 carbon atoms\\/m2, corresponding to a linear depth of 16?m for the density of 1.7×103kg\\/m3. The

T. Hayashi; K. Sugiyama; M. Mayer; K. Krieger; K. Masaki; T. Tanabe; M. Sato

2009-01-01

192

Development and Operation of the Lower Hybrid Range of Frequency System on JT-60U  

SciTech Connect

Development and operation of a lower hybrid range of frequency (LHRF) system for JT-60U are presented. The LHRF system was constructed in 1986 to study current drive and plasma heating at high injection power. Its main specifications are the total output power 24 MW with 24 high power klystrons, the frequency 1.74 to 2.23 GHz, and the injection power {approx}10 MW with three conventional antennas. To improve the antenna capabilities such as the current drive efficiency, N{sub //peak} controllability and the power injection properties, a 3-divided multi-junction type (CD1' launcher) and a 12-divided multi-junction type (CD2 launcher) are developed. The CD2 launcher can also reduce the number of the transmission lines to one fourth of the original system. The injection power {approx}7 MW is attained, and then the highest current drive efficiency 3.5 x 10{sup 19} m{sup -2}AW{sup -1} and the highest non-inductive driven current 3.6 MA are achieved. The high power klystron capable of the cathode-heater operation times more than 3000 hours is improved. The outgassing rate is estimated with the CD2 launcher as 1-10 x 10{sup -6} Pam{sup 3}/sm{sup 2}, which is sufficiently small not to need the vacuum pumping system for the launcher. Heat load onto the launcher due to the ripple enhanced banana drift loss is first observed in NBI or ICRF heating. From investigation on antenna-plasma coupling, the gas puffing improves distant coupling.

Seki, M.; Ikeda, Y.; Maebara, S.; Moriyama, S.; Naito, O.; Anno, K.; Hiranai, S.; Shimono, M.; Shinozaki, S.; Terakado, M.; Yokokura, K.; Yamamoto, T.; Fujii, T. [Japan Atomic Energy Research Institute (Japan)

2002-09-15

193

Recent Technological Progress for Advanced Tokamak Research in JT-60U and JFT-2M  

SciTech Connect

For steady state advanced tokamak research with long pulse operations, JT-60U tokamak discharge, NBI and RF heating injection durations have been extended from 15 s to 65 s and from 10 s to 30 s respectively mainly by means of modifying their control systems and using derated power levels. In addition, technological issues for their long pulse injections with the heating systems have been solved as follows. The ion source of the negative ion NBI system was modified to increase gas conductance in the accelerator, which reduced the heat load to the grounded grid due to stripping loss to a level that enables operations of 2 MW for 30 s. A new method of controlling the anode voltage has been developed for sustaining the oscillation condition of a gyrotron in the electron cyclotron (EC) system. With this method, the EC injection duration has reached 16 s at 0.4 MW. To avoid serious damage of the LH launcher, a heat-resistant carbon grill LH antenna was implemented on the original stainless steel grill. To date, the advanced tokamak operations have been extended to {beta}{sub N} = 2.1 for 20 s. In JFT-2M, high {beta}{sub N} plasmas had been investigated with the vacuum vessel covered with ferritic steels. {beta}{sub N} of {approx}3.5 was obtained with r{sub wall}/a{approx}1.3-1.6 without serious influence of ferromagnetic walls (r{sub wall} is distance of the wall from a plasma center and a is minor radius of a plasma). This encourages the utilization of ferric steel as a structural material for future reactors.

Hosogane, N. [Japan Atomic Energy Research Institute (Japan)] (and others)

2005-04-15

194

The 110-GHz Electron Cyclotron Range of Frequency System on JT-60U: Design and Operation  

SciTech Connect

The electron cyclotron range of frequency (ECRF) system was designed and operated on the JT-60U to locally heat and control plasmas. The frequency of 110 GHz was adopted to inject the fundamental O-mode from the low field side with an oblique injection angle. The system is composed of four 1 MW-level gyrotrons, four transmission lines, and two antennae. The gyrotron is featured by a collector potential depression (CPD) and a gaussian beam output through a diamond window. The CPD enables JAERI to drive the gyrotron under the condition of the main DC voltage of 60 kV without a thyristor regulation. The gaussian mode from the gyrotron is effectively transformed to HE{sub 11} mode in the 31.75 mm diameter corrugated waveguide. About 75% of the output power of the gyrotrons can be injected into plasmas through the waveguides about 60 m in length. There are two antennae to control the deposition position of the EC wave during a plasma discharge. One is connected with three RF lines to steer the EC beams in the poloidal direction. The other is to control the EC beam in the toroidal and poloidal directions by two steerable mirrors.On the operation in 2000, the power of 1.5 to 1.6 MW for 3 s was successfully injected into plasmas using three gyrotrons. Local profile control was demonstrated by using the antennae. This capability was devoted to improve the plasma performance such as high T{sub e} production more than 15 keV and suppression of the MHD activities. In 2001, the fourth gyrotron, whose structure was improved for long pulse operation, has been installed for a total injection power of {approx}3 MW.

Ikeda, Y.; Kasugai, A.; Moriyama, S.; Kajiwara, K.; Seki, M.; Tsuneoka, M.; Takahashi, K.; Anno, K.; Hamamatsu, K.; Hiranai, S.; Ikeda, Yu.; Imai, T.; Sakamoto, K.; Shimono, M.; Shinozaki, S.; Terakado, M.; Yamamoto, T.; Yokokura, K.; Fujii, T. [Japan Atomic Energy Research Institute (Japan)

2002-09-15

195

Stabilization of neoclassical tearing mode by ECCD and its evolution simulation on JT-60U tokamak  

NASA Astrophysics Data System (ADS)

Stabilization of an m = 3/n = 2 neoclassical tearing mode (NTM) by a local electron cyclotron current drive (ECCD) has been studied in high ?p ELMy H-mode plasmas in the JT-60U tokamak. In the stabilization experiment, the electron cyclotron (EC) injection timing is scanned from the 'before mode onset' phase (preemptive ECCD) to the mode saturation phase (late ECCD). It has been demonstrated that the ECCD is more effective when it is applied before the mode onset and the critical timing for effective ECCD is related to the mode excitation phase. The EC power to prevent the 3/2 NTM excitation by preemptive ECCD is lower by about 20% compared with complete stabilization by late ECCD. Even when the 3/2 NTM is excited, the stabilization effect is stronger than for late ECCD. For a high performance plasma of the normalized beta, ?N = 3.0, the H-factor H89PL improves from 1.9 to 2.1 when the 3/2 NTM is suppressed. A numerical study has been made based on the modified Rutherford equation coupled with a 1.5D transport code and an EC code. The simulation reproduces well the time evolution of the magnetic island both at the growing and stabilizing phases. The simulation results show that it is important to adjust not only the EC current position but also its width to stabilize the NTM effectively. The reduction of EC power for NTM prevention in experiments for preemptive ECCD can be explained by the increase of the minimum seed island size for NTM excitation. This manuscript is based on the paper EX/7-4 presented at the 20th IAEA Fusion Energy Conference, Vilamoura, Portugal.

Nagasaki, K.; Isayama, A.; Hayashi, N.; Ozeki, T.; Takechi, M.; Oyama, N.; Ide, S.; Yamamoto, S.; JT-60 Team

2005-12-01

196

Acceleration of 500 keV Negative Ion Beams By Tuning Vacuum Insulation Distance On JT-60 Negative Ion Source  

SciTech Connect

Acceleration of a 500 keV beam up to 2.8 A has been achieved on a JT-60U negative ion source with a three-stage accelerator by overcoming low voltage holding which is one of the critical issues for realization of the JT-60SA ion source. In order to improve the voltage holding, preliminary voltage holding tests with small-size grids with uniform and locally intense electric fields were carried out, and suggested that the voltage holding was degraded by both the size and local electric field effects. Therefore, the local electric field was reduced by tuning gap lengths between the large size grids and grid support structures of the accelerator. Moreover, a beam radiation shield which limited extension of the minimum gap length was also optimized so as to reduce the local electric field while maintaining the shielding effect. These modifications were based on the experiment results, and significantly increased the voltage holding from <150 kV/stage for the original configuration to 200 kV/stage. These techniques for improvement of voltage holding should also be applicable to other large ion sources accelerators such as those for ITER.

Kojima, A.; Hanada, M.; Tanaka, Y.; Taniguchi, M.; Kashiwagi, M.; Inoue, T.; Umeda, N.; Watanabe, K.; Tobari, H. [Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193 (Japan); Kobayashi, S.; Yamano, Y. [Saitama University, Saitama, Saitama-ken, 338-8570 (Japan); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)

2011-09-26

197

Expanded study of feasibility of measuring in-flight 747/JT9D loads, performance, clearance, and thermal data  

NASA Technical Reports Server (NTRS)

The JT9D jet engine exhibits a TSFC loss of about 1 percent in the initial 50 flight cycles of a new engine. These early losses are caused by seal-wear induced opening of running clearances in the engine gas path. The causes of this seal wear have been identified as flight induced loads which deflect the engine cases and rotors, causing the rotating blades to rub against the seal surfaces, producing permanent clearance changes. The real level of flight loads encountered during airplane acceptance testing and revenue service and the engine's response in the dynamic flight environment were investigated. The feasibility of direct measurement of these flight loads and their effects by concurrent measurement of 747/JT9D propulsion system aerodynamic and inertia loads and the critical engine clearance and performance changes during 747 flight and ground operations was evaluated. A number of technical options were examined in relation to the total estimated program cost to facilitate selection of the most cost effective option. It is concluded that a flight test program meeting the overall objective of determining the levels of aerodynamic and inertia load levels to which the engine is exposed during the initial flight acceptance test and normal flight maneuvers is feasible and desirable. A specific recommended flight test program, based on the evaluation of cost effectiveness, is defined.

Sallee, G. P.; Martin, R. L.

1980-01-01

198

The 727 airplane side inlet low-speed performance confirmation model test for refanned JT8D engines  

NASA Technical Reports Server (NTRS)

The results of a low-speed wind tunnel test of a 0.3 scale model 727 airplane side inlet for JT8D-100 engines are presented. The objectives of the test were to develop lines for a full-scale flightworthy inlet, to evaluate inlet total pressure recovery and steady-state total pressure distortion, and to obtain model-scale distortion data which can be used in the assessment of the compatibility of the inlet with the JT8D-100 series engines. A secondary objective was to obtain internal/external cowl static pressures for the determination of nacelle loads. Two basic inlet models were tested at static, forward speed, angle-of-attack (inflow angle), and cross-wind conditions. One model was with and one without an acoustic ring. Two modifications to the models were also tested, one with the ring closer to the inlet throat and one with a larger lip. Test measurements consisted of inlet surface static pressure, engine face total pressure, inlet airflow, tunnel total pressure, tunnel total temperature and tunnel velocity. Total pressure traverses were taken directly behind the ring and strut. No dynamic measurements were taken.

Schuehle, A. L.

1974-01-01

199

76 FR 5066 - Airworthiness Directives; Pratt & Whitney JT8D-7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A...  

Federal Register 2010, 2011, 2012, 2013

...JT8D-7, -7A, -7B, -9, - 9A, -11, -15, -15A, -17, -17A, -17R, and -17AR...7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR...7, -7A, -7B, -9, - 9A, -11, -15, -15A, -17, -17A, -17R, and...

2011-01-28

200

Active Control of Inlet Noise on the JT15D Turbofan Engine  

NASA Technical Reports Server (NTRS)

This report presents the key results obtained by the Vibration and Acoustics Laboratories at Virginia Tech over the year from November 1997 to December 1998 on the Active Noise Control of Turbofan Engines research project funded by NASA Langley Research Center. The concept of implementing active noise control techniques with fuselage-mounted error sensors is investigated both analytically and experimentally. The analytical part of the project involves the continued development of an advanced modeling technique to provide prediction and design guidelines for application of active noise control techniques to large, realistic high bypass engines of the type on which active control methods are expected to be applied. Results from the advanced analytical model are presented that show the effectiveness of the control strategies, and the analytical results presented for fuselage error sensors show good agreement with the experimentally observed results and provide additional insight into the control phenomena. Additional analytical results are presented for active noise control used in conjunction with a wavenumber sensing technique. The experimental work is carried out on a running JT15D turbofan jet engine in a test stand at Virginia Tech. The control strategy used in these tests was the feedforward Filtered-X LMS algorithm. The control inputs were supplied by single and multiple circumferential arrays of acoustic sources equipped with neodymium iron cobalt magnets mounted upstream of the fan. The reference signal was obtained from an inlet mounted eddy current probe. The error signals were obtained from a number of pressure transducers flush-mounted in a simulated fuselage section mounted in the engine test cell. The active control methods are investigated when implemented with the control sources embedded within the acoustically absorptive material on a passively-lined inlet. The experimental results show that the combination of active control techniques with fuselage-mounted error sensors and passive control techniques is an effective means of reducing radiated noise from turbofan engines. Strategic selection of the location of the error transducers is shown to be effective for reducing the radiation towards particular directions in the farfield. An analytical model is used to predict the behavior of the control system and to guide the experimental design configurations, and the analytical results presented show good agreement with the experimentally observed results.

Smith, Jerome P.; Hutcheson, Florence V.; Burdisso, Ricardo A.; Fuller, Chris R.

1999-01-01

201

Investigation of performance deterioration of the CF6/JT9D, high-bypass ratio turbofan engines  

NASA Technical Reports Server (NTRS)

The aircraft energy efficiency program within NASA is developing technology required to improve the fuel efficiency of commercial subsonic transport aricraft. One segment of this program includes engine diagnostics which is directed toward determining the sources and causes of performance deterioration in the Pratt and Whitney Aircraft JT9D and General Electric CF6 high-bypass ratio turbofan engines and developing technology for minimizing the performance losses. Results of engine performance deterioration investigations based on historical data, special engine tests, and specific tests to define the influence of flight loads and component clearances on performance are presented. The results of analysis of several damage mechanisms that contribute to performance deterioration such as blade tip rubs, airfoil surface roughness and erosion, and thermal distortion are also included. The significance of these damage mechanisms on component and overall engine performance is discussed.

Ziemianski, J. A.; Mehalic, C. M.

1980-01-01

202

Deuterium depth profiling in graphite tiles not exposed to hydrogen discharges before air ventilation of JT-60U  

NASA Astrophysics Data System (ADS)

Depth profiles of deuterium trapped in graphite tiles not exposed to hydrogen discharges just before air ventilation of JT-60U were determined based on the D( 3He,p) 4He resonant nuclear reaction analysis. The samples were taken from the W-shaped divertor. The maximum depth of analysis is about 1.4 × 10 24 carbon atoms/m 2, corresponding to a linear depth of 16 ?m for the density of 1.7 × 10 3 kg/m 3. The highest concentration (19 at.%) was found at the surface of the inner divertor area, which was significantly higher than that exposed to H discharges at the same location. However in the deeper region, the deuterium concentrations without H discharges were lower than those with H discharges in 3 of 4 samples. These results indicate that hydrogen discharges can remove deuterium trapped only in the shallow region.

Hayashi, T.; Sugiyama, K.; Mayer, M.; Krieger, K.; Masaki, K.; Tanabe, T.; Sato, M.

2009-06-01

203

JT9D-70/59 Improved High Pressure Turbine Active Clearance Control System. [for specific fuel consumption improvement  

NASA Technical Reports Server (NTRS)

The JT9D-70/59 high pressure turbine active clearance control system was modified to provide reduction of blade tip clearance when the system is activated during cruise operation. The modification increased the flow capacity and air impingement effectiveness of the cooling air manifold to augment turbine case shrinkage capability, and increased responsiveness of the airseal clearance to case shrinkage. The simulated altitude engine testing indicated a significant improvement in specific fuel consumption with the modified system. A 1000 cycle engine endurance test showed no unusual wear or performance deterioration effects on the engine or the clearance control system. Rig tests indicated that the air impingement and seal support configurations used in the engine tests are near optimum.

Gaffin, W. O.

1979-01-01

204

Study on development of double metal-sealed gate valve for the JT-60 radio frequency heating system  

SciTech Connect

The prospect of developing a 750-mm gate valve for the JT-60 radio frequency heating system is discussed. In order to decrease the sealing force applied to the gasket, a sealing system with two H-type gaskets and intermediate vacuum chamber (double seal type design) is planned. Tests for 103 cycles repeated operation at room temperature and 150/sup 0/C with a full-scale model of the valve seat confirm that valve seat leakage is less than 1.33 x 10/sup -9/ Pa.m/sup 3//s (1 x 10/sup -8/ Torr.l/s) for helium gas and the sealing force applied to the gasket is less than 9.81 x 10/sup 4/ N/m (10 kgf/mm).

Minami, M.; Imai, T.; Morita, H.; Nagashima, T.

1984-09-01

205

Comparison of several inflow control devices for flight simulation of fan tone noise using a JT15D-1 engine  

NASA Technical Reports Server (NTRS)

To enable accurate simulation of in-flight fan tone noise during ground static tests, four devices intended to reduce inflow disturbances and turbulence were tested with a JT15D-1 turbofan engine. These inflow control devices (ICD's) consisted of honeycomb/screen structures mounted over the engine inlet. The ICD's ranged from 1.6 to 4 fan diameters in size, and differed in shape and fabrication method. All the ICD's significantly reduced the BPF tone in the far-field directivity patterns, but the smallest ICD's apparently introduced propagating modes which could be recognized by additional lobes in the speeds; at supersonic fan tip speed the smallest ICD's had some measurable loss, but the largest had no loss. Data from a typical transducer show that the unsteady inflow distortion modes (turbulence) were eliminated or significantly reduced when either of the ICD's was installed. However, some steady inflow distortion modes remained.

Mcardle, J. G.; Jones, W. L.; Heidelberg, L. J.; Homyak, L.

1980-01-01

206

Evaluation of two inflow control devices for flight simulation of fan noise using a JT15D engine  

NASA Technical Reports Server (NTRS)

Two inflow control devices, (ICD's) one in-duct and the other external to the duct, were tested on a JT15D engine to determine their ability to remove inflow turbulence without altering the sound transmission to the far field. The objective of the program was to develop means of accurately simulating flight fan noise on ground static test stands. The results generally indicated that both the in-duct and external ICD's were effective in reducing the inflow turbulence and the fan blade passing frequency tone generated by the turbulence. The external ICD was essentially transparent to the propagating fan tone but the in-duct ICD caused attenuation under most conditions.

Jones, W. L.; Mcardle, J. G.; Homyak, L.

1979-01-01

207

Numerical modeling of a 2 K J-T heat exchanger used in Fermilab Vertical Test Stand VTS-1  

NASA Astrophysics Data System (ADS)

Fermilab Vertical Test Stand-1 (VTS-1) has been in operation since 2007 for testing superconducting radio frequency (SCRF) cavities at 2 K. This test stand includes a heat exchanger consisting of a single layer; helically wound finned tube, upstream of the J-T valve. A finite difference thermal model has been developed in Engineering Equation Solver (EES) to study the thermal performance of this heat exchanger during refilling of the test stand. The model can predict heat exchanger performance under various other operating conditions and is therefore useful as a design tool for similar heat exchangers in other facilities. The present paper discusses the different operational modes of this heat exchanger and its thermal characteristics under these operational modes. Results of this model have been compared with experimental data gathered from the VTS-1 heat exchanger, and they are in good agreement with the present model.

Gupta, Prabhat Kumar; Rabehl, Roger

2014-07-01

208

Long pulse production of high current D{sup -} ion beams in the JT-60 negative ion source  

SciTech Connect

The first long pulse production of high power D{sup -} ion beams has been demonstrated in the JT-60 U negative ion sources, each of which was designed to produce 22 A, 500 keV D{sup -} ion beams. Voltage holding capability and the grid power loading were examined for long pulse production of high power D{sup -} ion beams. From the correlation between voltage holding and the light intensity of cathodoluminescence from the Fiber Reinforced Plastic insulators, the acceleration voltage for stable voltage holding capability was found to be less than 320-340 kV where the light was sufficiently suppressed. By tuning the extraction voltage, the grid power loadings in the ion sources were decreased to the allowable levels for long pulse injection without a significant reduction of the beam power. After tuning the acceleration and extraction voltages, D{sup -} ion beams of 12.5 and 9.8 A were produced at 340 keV with cesium seeding at a rate of {approx}14 {mu}g/s into the ion sources. The pulse duration of these D{sup -} ion beams was extended step by step, and then was successfully extended up to 18 s without degradation of the negative ion production. The D{sup -} ion beams were neutralized to yield 3.6 MW D{sup 0} beams by a gas cell, and then injected into the JT-60 U plasma. Further, a slight reduction of D{sup -} ion beam power allowed the longer injection duration of 21 s at a D{sup 0} beam power of 3.2 MW. The success in the long pulse production of a high power D{sup -} ion beam shows that negative ion beams can be produced during a few tens of seconds without degradations of negative ion production and the voltage holding in a large Cs-seeded negative ion source.

Hanada, M.; Kamada, M.; Akino, N.; Ebisawa, N.; Honda, A.; Kawai, M.; Kazawa, M.; Kikuchi, K.; Komata, M.; Mogaki, K.; Noto, K.; Ohshima, K.; Takenouchi, T.; Tanai, Y.; Usui, K.; Yamazaki, H.; Ikeda, Y.; Grisham, L. R. [Japan Atomic Energy Agency, 801-1 Mukohyama-Naka, Ibaraki 310-0193 (Japan); Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

2008-02-15

209

Role of convective amplification of n = 1 energetic particle modes for N-NB ion dynamics in JT-60U  

NASA Astrophysics Data System (ADS)

The hybrid code MEGA is used to simulate an abrupt large-amplitude event (ALE) in JT-60U shot E039672 that was strongly driven by a pair of negative-ion-based neutral beams (N-NBs). This configuration is known to be unstable to energetic particle modes (EPMs) with toroidal mode number n = 1. The purpose of this study is to look for a threshold with respect to the on-axis fast ion beta value, ?h0, beyond which the EPM undergoes convective amplification (CA) and causes significant fast ion transport. This is motivated by the hypothesis that such a threshold may work as a trigger mechanism for relaxation events, such as ALE. In order to facilitate quantitative comparisons with the experiment, a realistic geometry and bulk pressure is used. Furthermore, MEGA is initialized with a fast ion distribution computed for JT-60U by an orbit-following Monte-Carlo code, and a passive vacuum region allows particles to travel without encountering artificial loss boundaries. Consistently with the experiment, the simulation predicts a burst time of about 0.3 ms and peak magnetic fluctuation levels around ?B?/B < 10-3 at the plasma boundary. As ?h0 is increased, a gradual increase in the CA of the EPM and in the convective transport of both resonant and nonresonant particles is found. The absence of a sharp transition between low- and high-amplitude fluctuations leads to the conclusion that the onset of CA does not suffice as a trigger mechanism for ALE.

Bierwage, A.; Shinohara, K.; Aiba, N.; Todo, Y.

2013-07-01

210

Identification of static JT in copper(II) doped hexaimidazole M(II) lattices: M = Co and Ni: An EPR study  

NASA Astrophysics Data System (ADS)

Single crystal EPR studies on Cu(II) doped paramagnetic host lattices, hexaimidazole M(II) dichloride tetrahydrate (M = Co and Ni), isomorphous with M = Zn, have been carried out from room temperature to 77 K to understand the nature of Jahn-Teller (JT) distortion in these paramagnetic host systems. The paramagnetic impurity, doped in the present two paramagnetic host lattices, shows anisotropic EPR spectra with superhyperfine from ligands, even at room temperature. An interesting observation noticed in the EPR spectra at room temperature is that there are more resonances corresponding to the second site in the paramagnetic hosts than in the diamagnetic host at 4.2 K. This difference in behavior between the diamagnetic and paramagnetic host lattices indicates a change in the depth of the JT valleys. The spin Hamiltonian parameters are evaluated for Cu(II) ion in both the host lattices and the relaxation times have been calculated for the ion in cobalt host lattice only.

Velavan, K.; Venkatesan, R.; Sambasiva Rao, P.

2005-11-01

211

Beamlet deflection due to beamlet-beamlet interaction in a large-area multiaperture negative ion source for JT-60U  

SciTech Connect

The JT-60U negative ion source has been designed to produce high current beams of 22 A through grids of 1080 apertures (five segments with nine rows of 24 apertures). One of the key issues is to steer such a high current beam through the multiaperture grids in order to focus the overall beam envelope because the beamlet-beamlet interaction may deflect the outer beamlets outward due to unbalanced space charge repulsion. To clarify the beam deflection in the JT-60U negative ion source, the beamlet trajectory in a multiaperture ion source was calculated by a three-dimensional simulation code. The measured angles of the outmost beamlets were in agreement with the calculated results where space charge of the beamlets was taken into account. It is noticed that the deflection of the outermost beamlet due to the beamlet-beamlet interaction is saturated at 5.2 mrad outward for beamlets more than ten.

Kamada, M.; Hanada, M.; Ikeda, Y.; Grisham, L. R.; Jiang, W. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

2008-02-15

212

Some comparisons of the flyover noise characteristics of DC-9 aircraft having refanned and hardwalled JT8D engines, with special reference to measurement and analysis procedures  

NASA Technical Reports Server (NTRS)

Flyover noise measurements were made (using Federal Aviation Regulations, part 36 procedures) of two DC-9 aircraft, one equipped with refanned JT8D-109 engines and the other equipped with hardwalled JT8D-9 engines. NASA analyses show a refan centerline noise reduction of about 9.1 EPNdB and 10.0 EPNdB for takeoff with cutback and 50 deg. flap landing approach, respectively. A comparison of refan and hardwall PNLTM spectra shows that the refan noise reduction may be attributed to lower jet noise levels on takeoff and reduced high-frequency tonal content on landing approach. A general description of the test procedures and results are included along with detailed descriptions of the measurement and analysis systems.

Hosier, R. N.

1976-01-01

213

Charge exchange neutral particle measurements with natural diamond detector under the deuterium-deuterium neutron field on JT-60U tokamak  

SciTech Connect

A natural diamond detector (NDD) has been installed on the JT-60U tokamak to measure the flux and the energy distribution of charge exchange (CX) fast neutral particles. A NDD has many important advantages to be used as a CX neutral particle analyzer, for example very compact size, high energy resolution, and high radiation hardness etc., while the neutrons and {gamma} rays are a large noise source in the deuterium plasma. The shield was set up around the NDD to reduce those noises. Time-resolved energy distribution of CX neutral particles corresponding to injected beam energy have been successfully obtained under high intensity neutron yield Y{sub n}>10{sup 15} n/s. Further enhanced neutral particle fluxes during sawtooth oscillation and Alfven eigenmodes were observed with the NDD. The performance of the NDD as CX neutral particle spectrometer under high intensity neutron yield was demonstrated for the first time on JT-60U in this work.

Ishikawa, M.; Kusama, Y.; Takechi, M.; Nishitani, T.; Morioka, A.; Sasao, M.; Isobe, M.; Krasilnikov, A.; Kaschuck, Yu. A. [Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 319-0193 (Japan); Tohoku University, Sendai-shi, Miyagi 980-8578 (Japan); National Institute for Fusion Science, Toki, Gihu 509-5292 (Japan); Troitsk Institute of Innovating and Fusion Research (TRINITI) Troitsk, Moscow Region 142092 (Russian Federation)

2004-10-01

214

Charge exchange neutral particle measurements with natural diamond detector under the deuterium-deuterium neutron field on JT-60U tokamak  

NASA Astrophysics Data System (ADS)

A natural diamond detector (NDD) has been installed on the JT-60U tokamak to measure the flux and the energy distribution of charge exchange (CX) fast neutral particles. A NDD has many important advantages to be used as a CX neutral particle analyzer, for example very compact size, high energy resolution, and high radiation hardness etc., while the neutrons and ? rays are a large noise source in the deuterium plasma. The shield was set up around the NDD to reduce those noises. Time-resolved energy distribution of CX neutral particles corresponding to injected beam energy have been successfully obtained under high intensity neutron yield Yn>1015 n/s. Further enhanced neutral particle fluxes during sawtooth oscillation and Alfvén eigenmodes were observed with the NDD. The performance of the NDD as CX neutral particle spectrometer under high intensity neutron yield was demonstrated for the first time on JT-60U in this work.

Ishikawa, M.; Kusama, Y.; Takechi, M.; Nishitani, T.; Morioka, A.; Sasao, M.; Isobe, M.; Krasilnikov, A.; Kaschuck, Yu. A.

2004-10-01

215

Fully predictive time-dependent transport simulations of ITB plasmas in JET, JT-60U and DIII-D  

NASA Astrophysics Data System (ADS)

For the first time, the predictive capabilities of the mixed Bohm/GyroBohm, Weiland and 'retuned' GLF23 transport models are investigated with ITB discharges from the ITPA ITB database with fully predictive, time-dependent transport simulations. A range of plasma conditions is examined for JET, JT-60U and DIII-D discharges with internal transport barriers (ITBs). The simulations show that the Bohm/GyroBohm model is able to follow the time evolution of the discharge from the preheating phase without an ITB through the ITB onset phase until the high performance phase with fair accuracy in most cases in JET and JT-60U. This indicates the importance of the interplay between the magnetic shear and ?E×B flow shear in ITB formation since these are the mechanisms that govern the ITB physics in the model. In order to achieve good agreement in DIII-D, the ?-stabilization had to be included in the model, emphasizing the role played by the ?-stabilization in the physics of the ITBs. The Weiland and GLF23 transport models show limited agreement between the model predictions and experimental time evolution of the ITB and kinetic plasma profiles. The Weiland model does not form a clear ITB in any of the three tokamaks despite varying plasma profiles, such as the q-profile. On the other hand, the average temperatures and density are often in fair agreement with experimental values. The GLF23 model often predicts an ITB, but its radial location is often too far inside the plasma, or shrinks as the simulations proceed in time. Consequently, the central temperatures at the end of the simulations during the high performance phase are usually underestimated. It is worth noting that GLF23 features in general better predictions of the Te and Ti profiles outside the ITB than the other models studied. Achieving the quantitative capability to predict the multi-channel ITB dynamics with fully predictive, time-dependent transport simulations has turned out to be extremely challenging.

Tala, T.; Imbeaux, F.; Parail, V. V.; Bourdelle, C.; Corrigan, G.; Garbet, X.; Heading, D. J.; Litaudon, X.; Strand, P. I.; Weiland, J.; contributors, JET-EFDA

2006-05-01

216

Development of reversed shear plasmas with high bootstrap current fraction towards reactor relevant regime in JT-60U  

NASA Astrophysics Data System (ADS)

This paper reports the recent development of reversed shear plasmas with a high bootstrap current fraction (fBS) towards the reactor relevant regime. The previous operation regime of high fBS plasmas is limited at q95 > 8 because of the low beta limit, whereas q95 = 5-6 is envisaged in the DEMO reactor. In the 2008 JT-60U experimental campaign, the high fBS plasma was emphasized in the lower q95 regime by developing the large volume configuration close to the conducting wall for wall stabilization. Thanks to the wall stabilization, high fBS plasmas exceeding the no-wall beta limit are obtained at reactor relevant q95 ~ 5.3. Though the high fBS plasmas are terminated by destabilization of the resistive wall mode, a highly integrated performance is obtained. High values of HH98y2 ~ 1.7, ?N ~ 2.7, fBS ~ 0.92 and ne/nGW ~ 0.87 are simultaneously achieved under the reactor relevant conditions of low momentum input and electron temperature nearly equal to ion temperature.

Sakamoto, Y.; Matsunaga, G.; Oyama, N.; Suzuki, T.; Aiba, N.; Takenaga, H.; Isayama, A.; Shinohara, K.; Yoshida, M.; Takechi, M.; Fujita, T.; Ide, S.; Koide, Y.; Kamada, Y.; JT-60 Team

2009-09-01

217

The effect of the electron temperature and current density profiles on the plasma current decay in JT-60U disruptions  

NASA Astrophysics Data System (ADS)

The plasma current decay during the initial phase of the current quench in JT-60U disruption has been calculated by a disruption simulation code (DINA) using the measured electron temperature Te profile. In the case of fast plasma current decay, Te has a peaked profile immediately after a thermal quench and the Te profile does not change significantly during the initial phase of the current quench. On the other hand, in the case of a slow plasma current decay, the Te profile is broader immediately after the thermal quench, and the Te profile shrinks. The results of the DINA simulation show that the plasma internal inductance Li increases during the initial phase of the current quench, whereas the plasma external inductance Le does not change over time. If the plasma is represented by a simple electrical circuit, the time derivative of Li functions as a resistance on the plasma current decay. It was confirmed that the increase in Li is caused by current diffusion toward the core plasma due to the decrease in Te in the intermediate and edge regions.

Shibata, Y.; Isayama, A.; Miyamoto, S.; Kawakami, S.; Watanabe, K. Y.; Matsunaga, G.; Kawano, Y.; Lukash, V. E.; Khayrutdinov, R. R.; the JT-60 Team

2014-04-01

218

Surface discharge related properties of fiberglass reinforced plastic insulator for use in neutral beam injector of JT-60U  

SciTech Connect

Neutral beam injection (NBI) used for JT-60U is required to generate negative ions of 500 keV energies. To produce such high-energy ions, three-stage electrostatic accelerators consisting of three insulator rings made of fiberglass reinforced plastic (FRP) are applied. The surface discharges along FRP insulators are one of the most serious problems in the development of NBI. To increase the hold-off voltage against surface flashover events, it is necessary to investigate the FRP insulator properties related to surface discharges in vacuum. This paper describes surface flashover characteristics for FRP and alumina samples under vacuum condition. The results show that the fold-off voltages for FRP samples are inferior to those of alumina ceramics. In addition, measurement results of surface resistivity and volume resistivity under vacuum and atmospheric conditions, secondary electron emission characteristics, and cathodoluminescence under some keV electron beam irradiation are also reported. These are important parameters to analyze surface discharge of insulators in vacuum.

Yamano, Y.; Takahashi, M.; Kobayashi, S.; Hanada, M.; Ikeda, Y. [School of Science and Engineering, Saitama University (Japan); Japan Atomic Energy Agency (Japan)

2008-02-15

219

Titanium honeycomb acoustic lining structural and thermal test report. [for acoustic tailpipe for JT8D engine  

NASA Technical Reports Server (NTRS)

The results are presented of static, fatigue and thermal testing of titanium honeycomb acoustic panels representing the acoustic tailpipe for the Pratt and Whitney Aircraft JT8D Refan engine which is being studied for use on the Boeing 727-200 airplane. Test specimens represented the engine and tailpipe flange joints, the rail to which the thrust reverser is attached and shear specimens of the tailpipe honeycomb. Specimens were made in four different batches with variations in configuration, materials and processes in each. Static strength of all test specimens exceeded the design ultimate load requirements. Fatigue test results confirmed that aluminum brazed titanium, as used in the Refan tailpipe design, meets the fatigue durability objectives. Quality of welding was found to be critical to life, with substandard welding failing prematurely, whereas welding within the process specification exceeded the panel skin life. Initial fatigue testing used short grip length bolts which failed prematurely. These were replaced with longer bolts and subsequent testing demonstrated the required life. Thermal tests indicate that perforated skin acoustic honeycomb has approximately twice the heat transfer of solid skin honeycomb.

Joynes, D.; Balut, J. P.

1974-01-01

220

Surface discharge related properties of fiberglass reinforced plastic insulator for use in neutral beam injector of JT-60U.  

PubMed

Neutral beam injection (NBI) used for JT-60U is required to generate negative ions of 500 keV energies. To produce such high-energy ions, three-stage electrostatic accelerators consisting of three insulator rings made of fiberglass reinforced plastic (FRP) are applied. The surface discharges along FRP insulators are one of the most serious problems in the development of NBI. To increase the hold-off voltage against surface flashover events, it is necessary to investigate the FRP insulator properties related to surface discharges in vacuum. This paper describes surface flashover characteristics for FRP and alumina samples under vacuum condition. The results show that the fold-off voltages for FRP samples are inferior to those of alumina ceramics. In addition, measurement results of surface resistivity and volume resistivity under vacuum and atmospheric conditions, secondary electron emission characteristics, and cathodoluminescence under some keV electron beam irradiation are also reported. These are important parameters to analyze surface discharge of insulators in vacuum. PMID:18315145

Yamano, Y; Takahashi, M; Kobayashi, S; Hanada, M; Ikeda, Y

2008-02-01

221

Transient Response of Divertor Plasma During Transition to ELM Free H-Mode Phase in JT-60U  

NASA Astrophysics Data System (ADS)

A drop in divertor plasma density was observed during the transition to the ELM free H-mode phase as well as the drop in D? emission intensity in JT-60U. The time scale for the drop in divertor plasma density ranged from a few ms to several tens of ms. 2-D fluid divertor code simulations indicated that the time scale for the divertor plasma density drop was ranged from several tens of ms to a hundred ms, when thermal and particle diffusivities were instantly reduced in the main plasma edge with a constant recycling coefficient. When it was assumed that the recycling coefficient decreased with a decrease in heat flux and increased with a decrease in particle flux, the time scale was reduced to a few ms in the simulations accompanied by a reduction of edge thermal diffusivity. These results indicate that the sharp drop of the divertor plasma density concomitant with the sharp drop of the D? emission intensity on a time scale of a few ms can be ascribed to the change of plasma-wall interaction depending on the heat flux to the divertor plates.

Takenaga, Hidenobu; Oyama, Naoyuki; Asakura, Nobuyuki

222

Detailed in situ laser calibration of the infrared imaging video bolometer for the JT-60U tokamak  

SciTech Connect

The infrared imaging video bolometer (IRVB) in JT-60U includes a single graphite-coated gold foil with an effective area of 9x7 cm{sup 2} and a thickness of 2.5 {mu}m. The thermal images of the foil resulting from the plasma radiation are provided by an IR camera. The calibration technique of the IRVB gives confidence in the absolute levels of the measured values of the plasma radiation. The in situ calibration is carried out in order to obtain local foil properties such as the thermal diffusivity {kappa} and the product of the thermal conductivity k and the thickness t{sub f} of the foil. These quantities are necessary for solving the two-dimensional heat diffusion equation of the foil which is used in the experiments. These parameters are determined by comparing the measured temperature profiles (for kt{sub f}) and their decays (for {kappa}) with the corresponding results of a finite element model using the measured HeNe laser power profile as a known radiation power source. The infrared camera (Indigo/Omega) is calibrated by fitting the temperature rise of a heated plate to the resulting camera data using the Stefan-Boltzmann law.

Parchamy, H.; Peterson, B. J.; Konoshima, S.; Hayashi, H.; Seo, D. C.; Ashikawa, N

2006-10-15

223

Zeeman polarimetry measurement for edge current density determination using Li-beam probe on JT-60U.  

PubMed

Zeeman polarimetry system using Li-beam probe has been developed for the edge current density measurement in the JT-60U tokamak, which measures the polarization angle alpha (related to the pitch angle of the magnetic field) by means of photoelastic modulators, etalons, and phase sensitive detection using digital lock-in amplifiers with the accuracy in the alpha of Delta alpha approximately 0.1 degrees. The diagnostic has 20-channel viewing chords covering the plasma peripheral region of normalized minor radius r/a approximately 0.8-1 with a spatial resolution of up to approximately 1 cm. Li-beam injection with beam current of up to approximately 5 mA has been achieved. A new tuning method of the wavelength for the etalon has been demonstrated, scanning the beam acceleration voltage and keeping a beam current constant during a single shot. The peak wavelength of the etalon is adjusted in the direction to both blue- and redshifts by changing the angle of incidence and increasing the temperature, respectively. Time evolution of the edge current density profile has been determined for the current ramp experiment in the Ohmically heated discharges. In addition, the edge current density profile with the local peak of j(ped) approximately 0.15-0.25 MA/m(2) at r/a approximately 0.9 has been identified in the H-mode plasma, which is correlated with large pressure gradient in the pedestal region. PMID:20370173

Kamiya, K; Fujita, T; Kojima, A; Kubo, H

2010-03-01

224

Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system  

SciTech Connect

Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ?0.3?mm and ?0.4?mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30?keV) can be expected in the refraction system.

Tojo, H.; Hatae, T.; Hamano, T.; Sakuma, T.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan)] [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan)

2013-09-15

225

Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system.  

PubMed

Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ~0.3 mm and ~0.4 mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30 keV) can be expected in the refraction system. PMID:24089827

Tojo, H; Hatae, T; Hamano, T; Sakuma, T; Itami, K

2013-09-01

226

Characteristics of the H-mode pedestal in improved confinement scenarios in ASDEX Upgrade, DIII-D, JET and JT-60U  

NASA Astrophysics Data System (ADS)

Pedestal and global plasma parameters are compared in conventional ELMy H-modes and improved confinement discharges from ASDEX Upgrade (AUG), DIII-D, JET and JT-60U with varying net input power. Both electron and ion pedestal pressures are studied. The pedestal top pressure pPED increases moderately with power in all tokamaks, in broad agreement with the power dependence of the IPB98(y, 2) scaling. Higher pedestal pressures are observed in AUG improved H-modes and in JT-60U high ?pol discharges at q95 ~ 6.5 and high triangularity. For all machines and all scenarios a robust correlation between the total and the pedestal thermal stored energy is observed, with the ratio of the two varying between ~0.3 and 0.5. However the relative importance of pedestal and core confinement varies from regime to regime. In AUG the confinement improvement with respect to the IPB98(y, 2) scaling is due to improved pedestal confinement in improved H-modes with early heating and to both improved pedestal and core confinement in improved H-modes with late heating. In DIII-D hybrid discharges the increase in confinement factor compared with conventional H-modes is due to improved confinement in the plasma core. JT-60U reversed shear H-modes have strong internal transport barriers and thus improved core performance. In all four tokamaks improved edge stability is correlated with increasing total ?pol and H98(y,2) increases with pedestal ?pol. The analysed multimachine data set supports a scaling expression for the pedestal stored energy derived under the assumption that the dominant loss term for the pedestal is by thermal conduction in the edge transport barrier region.

Maggi, C. F.; Groebner, R. J.; Oyama, N.; Sartori, R.; Horton, L. D.; Sips, A. C. C.; Suttrop, W.; ASDEX Upgrade Team; Leonard, A.; Luce, T. C.; Wade, M. R.; DIII-D Team; Kamada, Y.; Urano, H.; JT-60U Team; Andrew, Y.; Giroud, C.; Joffrin, E.; de la Luna, E.; EFDA-JET Contributors for the Pedestal Physics Edge; Steady State Operation Topical Groups of ITPA

2007-07-01

227

Phase 2 program on ground test of refanned JT8D turbofan engines and nacelles for the 727 airplane. Volume 1: Summary  

NASA Technical Reports Server (NTRS)

The propulsion performance, acoustic, structural, and systems changes to a 727-200 airplane retrofitted with a refan modification of the JT8D turbofan engine are evaluated. Model tests, design of certifiable airplane retrofit kit hardware, manufacture of test hardware, ground test of a current production JT8D engine, followed by test of the same engine modified to the refan configuration, detailed analyses of the retrofit impact on airplane airworthiness, performance, and noise, and a preliminary analysis of retrofit costs are included. Results indicate that the refan retrofit of the 727-200 would be certifiable and would result in a 6-to 8 EPNdb reduction in effective perceived noise level (EPNL) at the FAR 36 measuring points and an annoyance-weighted footprint area reduction of 68% to 83%. The installed refan engine is estimated to provide 14% greater takeoff thrust at zero velocity and 10% greater thrust at 100 kn (51.4 m/s). There would be an approximate 0.6% increase in cruise specific fuel consumption (SFC). The refan engine performance in conjunction with the increase in stalled weight results in a range reduction of approximately 15% over the unmodified airplane at the same brake release gross weight (BRGW), with a block fuel increase of 1.5% to 3%. With the particular model 727 that was studied, however, it is possible to operate the airplane (with minor structural modifications) at a higher BRGW and increase the range up to approximately 15% relative to the nonrefanned airplane (with equal or slightly increased noise levels). The JT8D refan engine also improves the limited-field range of the airplane.

1975-01-01

228

Cruise Drag Results from High Speed Wind Tunnel Tests of NASA Refan JT8D Engine Nacelles on the Boeing 727-200  

NASA Technical Reports Server (NTRS)

High speed wind tunnel test results are presented showing the cruise drag effect of installing JT8D-109 Refan engines on a Boeing 727-200. Incremental drags of a refan center inlet and side nacelles are presented for several configuration variations. Static pressure distributions were obtained on the side nacelle strut and on the fuselage (above and below the strut). Oil flow photographs of selected configurations are also presented. In general the drag level of the refan installation is slightly better than predicted prior to the test and the drag rise is favorable.

Easterbrook, W. G.; Carlson, R. B.

1973-01-01

229

Thermal Output Response Analysis on the Thermocouples in the Beam Limiters for the JT-60 NBI Drift Duct. The Effective Thermal Conductivity Between the Thermocouple and the Beam Limiter.  

National Technical Information Service (NTIS)

Thermal output response analysis on the thermocouples in the beam limiters for the JT-60 NBI drift duct was performed. The thermocouple are set up to measure the axis displacement of extracted beams and to protect the beam limiters against the neutral bea...

M. Araki M. Kuriyama

1986-01-01

230

Temporal and spatial responses of temperature, density and rotation to electron cyclotron heating in JT-60U  

NASA Astrophysics Data System (ADS)

The temporal and spatial responses of electron channels (the electron density, ne, and the electron temperature, Te) and ion channels (the ion temperature, Ti, and the toroidal rotation velocity, V?) to central electron cyclotron heating (ECH) have been investigated in positive shear H-mode plasmas with a relatively peaked Ti profile and internal transport barrier (ITB) plasmas on JT-60U. Ion temperature decreases with ECH after the increase in the electron temperature in the core region. The time scale of the change in Ti is ?30-60 ms in H-mode plasmas and almost constant in radius. In ITB plasmas, the time scale is shorter around the ITB foot and becomes longer inside the ITB foot. The experimentally measured causality indicates that the decrease in Ti is consistent with the ion temperature gradient critical gradient reduction. This is also verified through a comparison with linear gyrokinetic stability analyses. The electron heat diffusivity increases with ECH in both H-mode and ITB plasmas, correlating to the increase in the ion heat diffusivity. Electron density with a relatively flat ne profile does not decrease with ECH. On the other hand, the electron density with a peaked ne profile decreases with ECH. The flattening of the ne profile is observed after the increase in the electron temperature in the core region. The time scale of the change in ne is about 200-350 ms. Linear gyrokinetic stability analyses imply that the growth rate of the trapped electron modes, which increase outward particle flux, becomes more pronounced during ECH. The counter intrinsic rotation with ECH is identified on H-mode plasmas with a small torque input (BAL-NBI). The counter intrinsic rotation is generated after the increase in the electron temperature and correlates to the change in the electron temperature with ECH around the EC deposition. The radial region where the counter intrinsic rotation is observed is wider than the radial region where the electron temperature varies with ECH. The time scale of the change in the toroidal rotation velocity is about 90-200 ms around the ECH deposition and longer than the time scale of the change in Te and Ti.

Yoshida, M.; Ide, S.; Takenaga, H.; Honda, M.; Urano, H.; Kobayashi, T.; Nakata, M.; Miyato, N.; Kamada, Y.

2013-08-01

231

Effect of resistivity profile on current decay time of initial phase of current quench in neon-gas-puff inducing disruptions of JT-60U  

SciTech Connect

According to an early work [Y. Shibata et al., Nucl. Fusion 50, 025015 (2010)] on the behavior of the plasma current decay in the JT-60U disruptive discharges caused by the radiative collapse with a massive neon-gas-puff, the increase of the internal inductance mainly determined the current decay time of plasma current during the initial phase of current quench. To investigate what determines the increase of the internal inductance, we focus attention on the relationship between the electron temperature (or the resistivity) profile and the time evolution of the current density profile and carry out numerical calculations. As a result, we find the reason of the increase of the internal inductance: The current density profile at the start of the current quench is broader than an expected current density profile in the steady state, which is determined by the temperature (or resistivity) profile. The current density profile evolves into peaked one and the internal inductance is increasing.

Kawakami, S.; Ohno, N. [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)] [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Shibata, Y.; Isayama, A.; Kawano, Y. [Japan Atomic Energy Agency, Naka 311-0193 (Japan)] [Japan Atomic Energy Agency, Naka 311-0193 (Japan); Watanabe, K. Y. [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan) [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); National Institute for Fusion Science, Toki 509-5292 (Japan); Takizuka, T. [Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan)] [Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan); Okamoto, M. [Ishikawa National College of Technology, Ishikawa 929-0392 (Japan)] [Ishikawa National College of Technology, Ishikawa 929-0392 (Japan)

2013-11-15

232

Improvement of uniformity of the negative ion beams by tent-shaped magnetic field in the JT-60 negative ion source.  

PubMed

Non-uniformity of the negative ion beams in the JT-60 negative ion source with the world-largest ion extraction area was improved by modifying the magnetic filter in the source from the plasma grid (PG) filter to a tent-shaped filter. The magnetic design via electron trajectory calculation showed that the tent-shaped filter was expected to suppress the localization of the primary electrons emitted from the filaments and created uniform plasma with positive ions and atoms of the parent particles for the negative ions. By modifying the magnetic filter to the tent-shaped filter, the uniformity defined as the deviation from the averaged beam intensity was reduced from 14% of the PG filter to ?10% without a reduction of the negative ion production. PMID:24593591

Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Kashiwagi, Mieko; Grisham, Larry R; Akino, Noboru; Endo, Yasuei; Komata, Masao; Mogaki, Kazuhiko; Nemoto, Shuji; Ohzeki, Masahiro; Seki, Norikazu; Sasaki, Shunichi; Shimizu, Tatsuo; Terunuma, Yuto

2014-02-01

233

Beam deflection by plasma grid filter current in the negative-ion source for JT-60U neutral beam injection system  

SciTech Connect

In the JT-60U negative-ion-based neutral beam injection system, the effect of negative ion and electron deflection by the plasma grid (PG) magnetic filter was studied. After a long-pulse operation of up to 19 s, a local melting was observed on the beamline near the ion source, facing the electron drift side of the PG magnetic field. It is confirmed that the experimental deflection of the negative-ion beam agrees well with the three-dimensional beam simulation result by taking account of the measured magnetic field. By using the code, it is found that some stripped electrons produced in the first acceleration gap pass through the down pitch of the multiple apertures in the next stage of acceleration grids, and then collide on the beamline around the melted location.

Umeda, N.; Ikeda, Y.; Hanada, M.; Inoue, T.; Kawai, M.; Kazawa, M.; Komata, M.; Mogaki, K.; Ohga, T. [Naka Fusion Institute, Japan Atomic Energy Agency, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan)

2006-03-15

234

Dynamics of energetic particle driven modes and MHD modes in wall-stabilized high-? plasmas on JT-60U and DIII-D  

NASA Astrophysics Data System (ADS)

In the wall-stabilized high-? plasmas in JT-60U and DIII-D, interactions between energetic particle (EP) driven modes (EPdMs) and edge localized modes (ELMs) have been observed. The interaction between the EPdM and ELM are reproducibly observed. Many EP diagnostics indicate a strong correlation between the distorted waveform of the EPdM and the EP transport to the edge. The waveform distortion is composed of higher harmonics (n ? 2) and looks like a density snake near the plasma edge. According to statistical analyses, ELM triggering by the EPdMs requires a finite level of waveform distortion and pedestal recovery. ELM pacing by the EPdMs occurs when the repetition frequency of the EPdMs is higher than the natural ELM frequency. EPs transported by EPdMs are thought to contribute to change the edge stability.

Matsunaga, G.; Okabayashi, M.; Aiba, N.; Boedo, J. A.; Ferron, J. R.; Hanson, J. M.; Hao, G. Z.; Heidbrink, W. W.; Holcomb, C. T.; In, Y.; Jackson, G. L.; Liu, Y. Q.; Luce, T. C.; McKee, G. R.; Osborne, T. H.; Pace, D. C.; Shinohara, K.; Snyder, P. B.; Solomon, W. M.; Strait, E. J.; Turnbull, A. D.; Van Zeeland, M. A.; Watkins, J. G.; Zeng, L.; the DIII-D Team; the JT-60 Team

2013-12-01

235

Neutron Emission Profile Measurement and Fast Charge Exchange Neutral Particle Flux Measurement for Transport Analysis of Energetic Ions in JT-60U  

NASA Astrophysics Data System (ADS)

This paper describes diagnostics for transport analysis of energetic ions in JT-60U. Line integrated neutron emission profiles are measured using Stilbene neutron detectors, which are installed as a neutron emission profile monitor. The flux and energy distribution of charge exchange neutral particles are measured using a natural diamond detector (NDD). These measurements in the presence of bursting instabilities in the frequency range of Alfvén Eigenmode induced by negative-ion-based neutral beam injection, which are called Abrupt Large-amplitude Events, indicate that energetic ions are transported from the core region in the plasma due to a resonance interaction between energetic ions and the instabilities. Development of a digital signal processing (DSP) system for a neutron detector and a NDD enabling a sampling rate in the MHz class is proceeding. The DSP system for the neutron detector successfully discriminates between neutrons and gamma-rays in tests using neutron/gamma-ray sources.

Ishikawa, Masao; Nishitani, Takeo; Kusama, Yoshinori; Sukegawa, Atsuhiko; Takechi, Manabu; Shinohara, Koji; Krasilnikov, Anatoli; Kashuck, Yuri; Sasao, Mamiko; Isobe, Mitsutaka; Baba, Mamoru; Itoga, Toshio

236

Development of a high-brightness and low-divergence lithium neutral beam for a Zeeman polarimetry on JT-60U  

SciTech Connect

A high-brightness and low-divergence neutral beam is obtained for a Zeeman polarimetry of edge plasmas on JT-60U. The electron density and the pitch angle of the magnetic field line, thus the plasma current density distribution, can be measured by the Zeeman polarimetry using the lithium beam. A thermionic ion source heated by an electron beam is developed in order to obtain the ion beam current extraction over 10 mA. The beam optics is designed after detailed numerical simulation taking the space charge effects into account because a low-divergence angle of the neutral lithium beam leads to a narrow spectrum of the beam emission. It is also necessary to keep the beam radius small for good spatial resolution due to a long beam line of 6.5 m. The newly developed ion gun is operated on a test stand which simulates the diagnostic arrangement on JT-60U. The ion beam current of 10 mA at a beam energy of 10 keV is successfully extracted from the ion source operated at the temperature over 1300 deg. C and focused by Einzel lens. The full width at half maximum radius of the ion beam at the neutralizer is about 9 mm. A sodium vapor neutralizer neutralizes the collimated ion beam fully at the temperature of 300 deg. C. The neutral beam profiles are measured at two locations of the beam line at Z=2.3 m (beam monitor position) and Z=6.5 m (plasma region). The half-width at half maximum radius of the neutral beam of 26 mm and the equivalent beam current of 3 mA with the beam divergence angle of 0.2 deg. which is the half-angle divergence are obtained. Those parameters satisfy the requirements of the Zeeman polarimetry. Furthermore, a long pulse extraction with a current of 10 mA and duration of 50 s is attained.

Kojima, Atshushi; Kamiya, Kensaku; Fujita, Takaaki; Kamada, Yutaka [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Iguchi, Harukazu [National Institution of Fusion Science, Toki, Gifu 509-5292 (Japan); Kakiuchi, Hideto [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

2008-09-15

237

Off-axis fishbone-like instability and excitation of resistive wall modes in JT-60U and DIII-D  

NASA Astrophysics Data System (ADS)

An energetic-particle (EP)-driven ``off-axis-fishbone-like mode (OFM)'' often triggers a resistive wall mode (RWM) in JT-60U and DIII-D devices, preventing long-duration high-?N discharges. In these experiments, the EPs are energetic ions (70-85 keV) injected by neutral beams to produce high-pressure plasmas. EP-driven bursting events reduce the EP density and the plasma rotation simultaneously. These changes are significant in high-?N low-rotation plasmas, where the RWM stability is predicted to be strongly influenced by the EP precession drift resonance and by the plasma rotation near the q=2 surface (kinetic effects). Analysis of these effects on stability with a self-consistent perturbation to the mode structure using the MARS-K code showed that the impact of EP losses and rotation drop is sufficient to destabilize the RWM in low-rotation plasmas, when the plasma rotation normalized by Alfvén frequency is only a few tenths of a percent near the q=2 surface. The OFM characteristics are very similar in JT-60U and DIII-D, including nonlinear mode evolution. The modes grow initially like a classical fishbone, and then the mode structure becomes strongly distorted. The dynamic response of the OFM to an applied n=1 external field indicates that the mode retains its external kink character. These comparative studies suggest that an energetic particle-driven ``off-axis-fishbone-like mode'' is a new EP-driven branch of the external kink mode in wall-stabilized plasmas, analogous to the relationship of the classical fishbone branch to the internal kink mode.

Okabayashi, M.; Matsunaga, G.; Degrassie, J. S.; Heidbrink, W. W.; in, Y.; Liu, Y. Q.; Reimerdes, H.; Solomon, W. M.; Strait, E. J.; Takechi, M.; Asakura, N.; Budny, R. V.; Jackson, G. L.; Hanson, J. M.; La Haye, R. J.; Lanctot, M. J.; Manickam, J.; Shinohara, K.; Zhu, Y. B.

2011-05-01

238

DC-9/JT8D refan, Phase 1. [technical and economic feasibility of retrofitting DC-9 aircraft with refan engine to achieve desired acoustic levels  

NASA Technical Reports Server (NTRS)

Analyses and design studies were conducted on the technical and economic feasibility of installing the JT8D-109 refan engine on the DC-9 aircraft. Design criteria included minimum change to the airframe to achieve desired acoustic levels. Several acoustic configurations were studied with two selected for detailed investigations. The minimum selected acoustic treatment configuration results in an estimated aircraft weight increase of 608 kg (1,342 lb) and the maximum selected acoustic treatment configuration results in an estimated aircraft weight increase of 809 kg (1,784 lb). The range loss for the minimum and maximum selected acoustic treatment configurations based on long range cruise at 10 668 m (35,000 ft) altitude with a typical payload of 6 804 kg (15,000 lb) amounts to 54 km (86 n. mi.) respectively. Estimated reduction in EPNL's for minimum selected treatment show 8 EPNdB at approach, 12 EPNdB for takeoff with power cutback, 15 EPNdB for takeoff without power cutback and 12 EPNdB for sideline using FAR Part 36. Little difference was estimated in EPNL between minimum and maximum treatments due to reduced performance of maximum treatment. No major technical problems were encountered in the study. The refan concept for the DC-9 appears technically feasible and economically viable at approximately $1,000,000 per airplane. An additional study of the installation of JT3D-9 refan engine on the DC-8-50/61 and DC-8-62/63 aircraft is included. Three levels of acoustic treatment were suggested for DC-8-50/61 and two levels for DC-8-62/63. Results indicate the DC-8 technically can be retrofitted with refan engines for approximately $2,500,000 per airplane.

1973-01-01

239

Flight effects on noise generated by the JT8D-17 engine in a quiet nacelle and a conventional nacelle as measured in the NASA-Ames 40- by 80-foot wind tunnel  

NASA Technical Reports Server (NTRS)

A JT8D-17 turbofan engine was tested in the NASA-Ames 40- by 80-foot wind tunnel to determine flight effects on jet and fan noise. Baseline, quiet nacelle with 20-lobe ejector/suppressor, and internal mixer configurations were tested over a range of engine power settings and tunnel velocities. Flight effects derived from the 40- by 80-foot wind tunnel test are compared with 727/JT8D flight test data and with model data obtained in a smaller wind tunnel. Procedures are defined for measuring noise data in a wind tunnel relatively near the sources and analyzing the results to obtain far-field flight effects. Wind tunnel and 727 flight test noise results compare favorably for both the baseline and quiet nacelle configurations. Two reports are provided, including a comprehensive version with extensive test results and analysis and the subject summary version that emphasizes data analysis and program finding.

Strout, F. G.

1976-01-01

240

Development of a high-brightness and low-divergence lithium neutral beam for a Zeeman polarimetry on JT-60U.  

PubMed

A high-brightness and low-divergence neutral beam is obtained for a Zeeman polarimetry of edge plasmas on JT-60U. The electron density and the pitch angle of the magnetic field line, thus the plasma current density distribution, can be measured by the Zeeman polarimetry using the lithium beam. A thermionic ion source heated by an electron beam is developed in order to obtain the ion beam current extraction over 10 mA. The beam optics is designed after detailed numerical simulation taking the space charge effects into account because a low-divergence angle of the neutral lithium beam leads to a narrow spectrum of the beam emission. It is also necessary to keep the beam radius small for good spatial resolution due to a long beam line of 6.5 m. The newly developed ion gun is operated on a test stand which simulates the diagnostic arrangement on JT-60U. The ion beam current of 10 mA at a beam energy of 10 keV is successfully extracted from the ion source operated at the temperature over 1300 degrees C and focused by Einzel lens. The full width at half maximum radius of the ion beam at the neutralizer is about 9 mm. A sodium vapor neutralizer neutralizes the collimated ion beam fully at the temperature of 300 degrees C. The neutral beam profiles are measured at two locations of the beam line at Z=2.3 m (beam monitor position) and Z=6.5 m (plasma region). The half-width at half maximum radius of the neutral beam of 26 mm and the equivalent beam current of 3 mA with the beam divergence angle of 0.2 deg which is the half-angle divergence are obtained. Those parameters satisfy the requirements of the Zeeman polarimetry. Furthermore, a long pulse extraction with a current of 10 mA and duration of 50 s is attained. PMID:19044408

Kojima, Atshushi; Kamiya, Kensaku; Iguchi, Harukazu; Fujita, Takaaki; Kakiuchi, Hideto; Kamada, Yutaka

2008-09-01

241

Modifications to the edge radial electric field by angular momentum injection in JT-60U and their implication for pedestal transport  

NASA Astrophysics Data System (ADS)

The first detailed measurements of ion-impurity dynamics for NBI-heated ELMy H-modes at the edge of the JT-60U tokamak are reported. We investigated the ability of external momentum/power input to modify and control the radial electric field, Er, and pedestal structures. The relationship between Er and pedestal structures of ion-impurity density, ni, and temperature, Ti, during the ELMing H-mode phase for various momentum input directions (i.e. co-, balanced- and counter-NBI) and input powers from perpendicular NBI are compared with the ELM-free phase. The observed trend is that the edge Er-well width increases in the co-NBI discharge, while the Er value at the base of the Er-well becomes more negative in the counter-NBI discharge. The scale length for both ni and Ti in the pedestal is ˜2 cm and \\eta _i \\equiv L_{n_i} /L_{T_i} values are ˜1 for both ELM-free and ELMing phases with different magnitudes of Er (and/or Er shear). Characteristics of the turbulent density fluctuation, in addition to a uniform toroidal MHD oscillation (i.e. n = 0), during both ELM-free and ELMing phases are also reported.

Kamiya, K.; Honda, M.; Miyato, N.; Urano, H.; Yoshida, M.; Sakamoto, Y.; Matsunaga, G.; Oyama, N.; Koide, Y.; Kamada, Y.; Ida, K.; Murakami, I.

2012-11-01

242

Phase 2 program on ground test of refanned JT8D turbofan engines and nacelles for the 727 airplane. Volume 4: Airplane evaluation and analysis  

NASA Technical Reports Server (NTRS)

The retrofit of JT8D-109 (refan) engines are evaluated on a 727-200 airplane in terms of airworthiness, performance, and noise. Design of certifiable hardware, manufacture, and ground testing of the essential nacelle components is included along with analysis of the certifiable airplane design to ensure airworthiness compliance and to predict the in-flight performance and noise characteristics of the modified airplane. The analyses confirm that the 727 refan airplane is certifiable. The refan airplane range would be 15% less that of the baseline airplane and block fuel would be increased by 1.5% to 3%. However, with this particular 727-200 model, with a brake release gross weight of 172,500 lb (78,245 kg), it is possible to operate the airplane (with minor structural modifications) at higher gross weights and increase the range up to 15% over the 727-200 (baseline) airplane. The refan airplane FAR Part 36 noise levels would be 6 to 8 EPNdB (effective perceived noise in decibels) below the baseline. Noise footprint studies showed that approach noise contour areas are small compared to takeoff areas. The 727 refan realizes a 68% to 83% reduction in annoyance-weighted area when compared to the 727-200 over a range of gross weights and operational procedures.

1975-01-01

243

Measurement of type-I edge localized mode pulse propagation in scrape-off layer using optical system of motional Stark effect diagnostics in JT-60U  

SciTech Connect

Propagation of plasma ejected by type-I edge localized mode (ELM) has been measured in scrape-off layer (SOL) of the JT-60U tokamak, using optical system of motional Stark effect (MSE) diagnostics as beam emission spectroscopy (BES) diagnostics through a new technique developed. This MSE/BES system measures D{alpha} emission from heating neutral beam excited by collisions with the ejected plasma, as well as background light (e.g., bremsstrahlung). While spatio-temporal change in the beam emission gives information on propagation of the ejected plasma, the background light that is observed simultaneously in all spatial channels veils the information. In order to separate the beam emission and the background light, a two-wavelength detector is newly introduced into the MSE/BES system. The detector observes simultaneously at the same spatial point in two distinct wavelengths using two photomultiplier tubes through two interference filters. One of the filters is adjusted to the central wavelength of the beam emission for the MSE diagnostics, and the other is outside the beam emission spectrum. Eliminating the background light, temporal change in the net beam emission in the SOL has been evaluated. Comparing conditionally averaged beam emission with respect to 594 ELMs in a discharge at five spatial channels (0.02-0.3 m outside the main plasma near equatorial plane), radial velocity of the ELM pulse propagation in SOL is evaluated to be 0.8-1.8 km/s ({approx}1.4 km/s for least-mean-squared fitting).

Suzuki, T.; Oyama, N.; Asakura, N. [Japan Atomic Energy Agency, 801-1, Mukoyama, Naka, Ibaraki 311-0193 (Japan)

2010-04-15

244

The results of a high-speed wind tunnel test to investigate the effects of the NASA refan JT8D engine nacelles on the stability and control characteristics of the Boeing 727 airplane  

NASA Technical Reports Server (NTRS)

A high speed wind tunnel test was conducted to investigate the effects of the NASA Refan JT8D engine nacelles on the stability and control characteristics of the Boeing 727 airplane. The test was performed at the Calspan Corporation 8x8 ft. (2.44x2.44 m.) transonic wind tunnel. Both the 727-200 and -100 models were tested. A small nose-down pitching moment increment and a slight increase in longitudinal stability were noted due to the Refan nacelles. The directional stability of the 727-200 airplane increased up to 10 percent. A smaller improvement was observed on the 727-100 model. In general, the high speed stability and control characteristics of the basic airplane are not significantly altered by the Refan nacelle installation.

Kupcis, E. A.

1973-01-01

245

The results of a low-speed wind tunnel test to investigate the effects of the Refan JT8D engine target thrust reverser on the stability and control characteristics of the Boeing 727-200 airplane  

NASA Technical Reports Server (NTRS)

The effects of the Refan JT8D side engine target thrust reverser on the stability and control characteristics of the Boeing 727-200 airplane were investigated using the Boeing-Vertol 20 x 20 ft Low-Speed Wind Tunnel. A powered model of the 727-200 was tested in groud effect in the landing configuration. The Refan target reverser configuration was evaluated relative to the basic production 727 airplane with its clamshell-deflector door thrust reverser design. The Refan configuration had slightly improved directional control characteristics relative to the basic airplane. Clocking the Refan thrust reversers 20 degrees outboard to direct the reverser flow away from the vertical tail, had little effect on directional control. However, clocking them 20 degrees inboard resulted in a complete loss of rudder effectiveness for speeds greater than 90 knots. Variations in Refan reverser lip/fence geometry had a minor effect on directional control.

Kupcis, E. A.

1974-01-01

246

The results of a low speed wind tunnel test to investigate the effects of installing refan JT8D engines on the McDonnell Douglas DC-9-30  

NASA Technical Reports Server (NTRS)

A low speed wind tunnel test was conducted to assess the effects of the larger JT8D refan nacelles on the stability and control characteristics of the DC-9-30, with emphasis on the deep stall regime. Deep stall pitching moment and elevator hinge moment data, and low angle of attack tail-on and tail-off pitching moment data are presented. The refan nacelle was tested in conjunction with various pylons of reduced span relative to the production DC-9-30 pylon. Also, a horizontal tail that was larger than the production tail was tested. The data show that the refan installation has a small detrimental effect on the DC-9-30 deep stall recovery capability, that recovery characteristics are essentially independent of pylon span, and that the larger horizontal tail significantly increases recovery margins. The deep stall characteristics with the refan installation, within the range of pylon spans tested, are acceptable with no additional design changes anticipated.

Chrisenberry, H. E.; Doss, P. G.; Kressly, A. E.; Prichard, R. D.; Thorndike, C. S.

1973-01-01

247

Crystal structure of Vibrionaceae Photobacterium sp. JT-ISH-224 alpha2,6-sialyltransferase in a ternary complex with donor product CMP and acceptor substrate lactose: catalytic mechanism and substrate recognition.  

PubMed

Sialyltransferases are a family of glycosyltransferases that catalyze the transfer of N-acetylneuraminic acid residues from cytidine monophosphate N-acetylneuraminic acid (CMP-NeuAc) as a donor substrate to the carbohydrate groups of glycoproteins and glycolipids as acceptor substrates. We determined the crystal structure of Delta16psp26ST, the N-terminal truncated form of alpha2,6-sialyltransferase from Vibrionaceae Photobacterium sp. JT-ISH-224, complexed with a donor product CMP and an acceptor substrate lactose. Delta16psp26ST has three structural domains. Domain 1 belongs to the immunoglobulin-like beta-sandwich fold, and domains 2 and 3 form the glycosyltransferase-B structure. The CMP and lactose were bound in the deep cleft between domains 2 and 3. In the structure, only Asp232 was within hydrogen-binding distance of the acceptor O6 carbon of the galactose residue in lactose, and His405 was within hydrogen-binding distance of the phosphate oxygen of CMP. Mutation of these residues greatly decreased the activity of the enzyme. These structural and mutational results indicated that Asp232 might act as a catalytic base for deprotonation of the acceptor substrate, and His405 might act as a catalytic acid for protonation of the donor substrate. These findings are consistent with an in-line-displacement reaction mechanism in which Delta16psp26ST catalyzes the inverting transfer reaction. Unlike the case with multifunctional sialyltransferase (Delta24PmST1) complexed with CMP and lactose, the crystal structure of which was recently reported, the alpha2,6 reaction specificity of Delta16psp26ST is likely to be determined by His123. PMID:17962295

Kakuta, Yoshimitsu; Okino, Nozomu; Kajiwara, Hitomi; Ichikawa, Masako; Takakura, Yoshimitsu; Ito, Makoto; Yamamoto, Takeshi

2008-01-01

248

J.T. Roberts' Science Fair  

NSDL National Science Digital Library

The following websites will be useful when preparing your science fair project. It is that time of year again! It is time to start planning your science fair project. All 7th and 8th grade students are required to participate in in the science fair. This is an opportunity to explore the exciting world in which we live. REQUIREMENTS: - Students will work ...

Greeley, Ms.

2007-11-03

249

JT/LJT connector insert material evaluation  

SciTech Connect

Different insert (insulator) materials are undergoing evaluation to replace the Fiberite E-3938 BE96 material currently used. Also being evaluated is the reconfiguration of the insert and metal shell-edge geometries for the purpose of reducing the alleged interference principally responsible for insert damage.

Baca, J.R.F.

1991-10-01

250

JT9D jet engine performance deterioration  

NASA Technical Reports Server (NTRS)

The analytical techniques utilized to examine the effects of flight loads and engine operating conditions on performance deterioration are presented. The role of gyroscopic, gravitational, and aerodynamic loads are shown along with the effect of variations in engine build clearances. These analytical results are compared to engine test data along with the correlation between analytically predicted and measured clearances and rub patterns. Conclusions are drawn and important issues are discussed.

Jay, A.; Todd, E. S.; Sallee, G. P.

1978-01-01

251

Triton burnup study in JT-60U  

SciTech Connect

The behavior of 1 MeV tritons produced in the d(d,p)t reaction is important to predict the properties of D-T produced 3.5 MeV alphas because 1 MeV tritons and 3.5 MeV alphas have similar kinematic properties, such as Larmor radius and precession frequency. The confinement and slowing down of the fast tritons were investigated by measuring the 14 MeV and the 2.5 MeV neutron production rates. Here the time resolved triton burnup measurements have been performed using a new type 14 MeV neutron detector based on scintillating fibers, as part of a US-Japan tokamak collaboration. Loss of alpha particles due to toroidal ripple is one of the most important issues to be solved for a fusion reactor such as ITER. The authors investigated the toroidal ripple effect on the fast triton by analyzing the time history of the 14 MeV emission after NB turn-off.

Nishitani, T.; Hoek, M.; Isobe, M.; Tobita, K.; Kusama, Y. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Harano, H. [Univ. of Tokyo (Japan). Dept. of Engineering; Wurden, G.A.; Chrien, R.E. [Los Alamos National Lab., NM (United States)

1995-10-01

252

Predicting Mothers' Reports of Children's Mental Health Three Years after Hurricane Katrin.  

PubMed

This study explored pathways through which hurricane-related stressors affected the psychological functioning of elementary school aged children who survived Hurricane Katrina. Participants included 184 mothers from the New Orleans area who completed assessments one year pre-disaster (Time 1), and one and three years post-disaster (Time 2 and Time 3, respectively). Mothers rated their children's behavior problems at Time 3 only (n = 251 children; 53.0% male; Mean age: 10.19 years, SD = 1.68 years). A path analytic model indicated that hurricane-related stressors were associated with increased maternal psychological distress and school mobility in the first post-disaster year, which were associated with higher child internalizing and externalizing symptoms three years post-disaster. Mediation analysis indicated that hurricane-related stressors were associated with child symptoms indirectly, through their impact on maternal psychological distress. Findings underscore the importance of interventions that boost maternal and child mental health and support children through post-disaster school transitions. PMID:23471125

Lowe, Sarah R; Godoy, Leandra; Rhodes, Jean E; Carter, Alice S

2013-01-01

253

Clean-up of graphite first walls in JT-60  

NASA Astrophysics Data System (ADS)

During the venting period from April to May 1987 about a half of TiC-coated molybdenum and Inconel 625 first walls were removed and graphite first walls were installed. The overall surface area and the weight of the graphite tiles are 200 m 2 and 3500 kg, respectively. Two kinds of isotropic graphite (Ibiden ETP-10 and Hitachi-Chemical HCB-18S) were used. Special attention was paid to the contamination of the graphite first walls during the courses of fabrication and installation. Main discharge were tried after 7 d conditioning, which included 3 d bakeout at the temperature of 300°C, 18 h glow discharge cleaning and 36 h Taylor-type discharge cleaning keeping the vessel temperature around 280°C. A 0.5 MA stable plasma was successfully attained at the 6th shot and a very rapid start-up of the discharge conditioning with plasma current up to 1 MA was achieved with 14 shots. An ultimate pressure of 6.4 × 10 -7 Pa was obtained with the vessel temperature at RT and the residual gases were water, carbon oxide and carbon hydride.

Arai, T.; Takatsu, H.; Ninomiya, H.; Yoshino, R.; Hosogane, N.; Yamamoto, M.; Kodama, K.; Kaminaga, A.; Shimizu, M.; JT-60 Team

1989-04-01

254

Sorption J-T refrigeration utilizing manganese nitride chemisorption  

NASA Technical Reports Server (NTRS)

The equilibrium pressures and compositions have been measured for a system of finely powdered manganese nitride and nitrogen gas at 650, 700, 800, and 850 C for various nitrogen loadings. Pressures ranged from less than 0.02 MPa at 650 C to 6.38 MPa at 850 C. Analysis of the test results has shown that under certain conditions Mn(x)N(y) could potentially be used in a triple regenerative sorption compressor refrigeration system, but the potential power savings are small compared to the increased complexity and reliability problems associated with very high temperature (above 950 C) pressurized systems.

Jones, Jack; Lund, Alan

1990-01-01

255

Miniature J-T refrigators using adsorption compressors  

NASA Astrophysics Data System (ADS)

More sophisticated cooling systems for the employed detectors will be needed to satisfy the demand for higher resolution and sensitivity of various detectors used in space missions. The design of the cooling system must take into consideration the unique environment of space vehicles. It is pointed out that a deep space vehicle usually has an ample supply of waste heat from a radioisotope thermoelectric generator (RTG) and has a heat sink near zero Kelvin. Passive radiative coolers have been used for cooling temperatures above 90 K. Cooling below 90 K is currently handled by phase changes of solid or liquid cryogens or mechanical refrigeration. However, the weight of the cryogen may be a problem in a long duration space mission. Refrigerators of small cooling capacity are required in many spacecraft applications. For some future NASA missions, a multistage Joule-Thomson refrigerator using adsorption compressors appears particularly attractive. A study is discussed of four different refrigeration stages which use charcoal as the adsorbent. The adsorbed gases are nitrogen, helium, hydrogen, and neon.

Chan, C. K.; Tward, E.; Elleman, D. D.

256

Development of a low noise 10K JT. Refrigeration system  

NASA Astrophysics Data System (ADS)

This report summarizes the results of an engineering design program to develop a low noise, closed cycle, Joule-Thomson, microminiature refrigeration system for 10K operation. During this period the effort has been focused on the fabrication of the argon and hydrogen stages of the three stage cooler. A test facility was designed and built which allows one to mount each refrigerator on a separate removable base and to test each in turn. Key to the successful fabrication of the refrigerator is the determination of the proper firing profile for sealing the refrigerator components. Three batches of refrigerators have been built to date, and reasonable yields are now being obtained for the fabrication of these stages. The helium stage has been designed and laid out, and the photomasks prepared. Work has continued on the hydraulically actuated compressor.

1986-02-01

257

Monte Carlo calculations of the intrinsic detector backgrounds for the Karlsruhe Tritium Neutrino Experiment  

Microsoft Academic Search

The Karlsruhe Tritium Neutrino Experiment (KATRIN) aims to measure the absolute neutrino mass, an open question in neutrino physics. KATRIN exploits the fact that the beta-decay spectral shape near the endpoint depends on the neutrino mass. Using a gaseous tritium source and a precise electrostatic spectrometer, KATRIN will measure the integral beta-decay spectrum in a silicon detector. KATRIN strives for

Michelle L. Leber

2010-01-01

258

Studies on Structural Analysis Related to the Design of the JT-60 Vacuum Vessel.  

National Technical Information Service (NTIS)

Studies on structural analysis of a vacuum vessel of tokamak-type fusion devices are presented. The present studies are proposals for the structural analysis procedures of the tokamak-type fusion devices and are composed of five parts, each of which cover...

H. Takatsu

1987-01-01

259

Development of a low noise 10K J-T refrigeration system. Final technical report  

SciTech Connect

This report summarizes the results of an engineering design program to develop a low-noise, closed-cycle, Joule-Thomson, microminiature refrigeration system for 10K operation. During this period, the effort focused on the fabrication of the argon and hydrogen stages of the three-stage cooler. A test facility was designed and built which allows one to mount each refrigerator on a separate removable base and to test each in turn. Key to the successful fabrication of the refrigerator is the determination of the proper firing profile for sealing the refrigerator components. Three batches of refrigerators have been built to date, and reasonable yields are now being obtained for the fabrication of these stages. The helium stage has been designed and laid out, and the photomasks prepared. Work has continued on the hydraulically actuated compressor.

Not Available

1986-02-01

260

Development of a low-noise 10 K J-T refrigeration system. Technical progress report  

SciTech Connect

This report summarizes work done on the development of a low noise Joule-Thomson, microminiature refrigeration system design for 10K operation. Good progress has been made on the compressor and on the waterknife to be used for the fabrication of the refrigerators. Work on the refrigerator itself is progressing well. Difficulties which had been experienced previously resulting in the warming of the nitrogen stage precooler appear to be due to inefficiency of the final stage laminar flow heat exchanger. This inefficiency is strongly dependent upon the mass flow through this stage, and difficulty in controlling this to the required precision caused the wide range of variations in the performance of otherwise similar coolers.

Little, W.A.

1990-02-15

261

Particle balance under global wall saturation in long-pulse discharges of JT-60U  

NASA Astrophysics Data System (ADS)

During 30s-ELMy H-mode discharges, the wall-pumping rate decreases with a decay constant of several seconds and then becomes constant. During the constant wall-pumping phase, in discharges with a density of 65% of the Greenwald density, the wall-pumping rate is negative, in other words, outgassing. It has been found that this outgassing rate correlates with an increase in the tile temperature around the outer strike point. In discharges with a density of 80% of the Greenwald density, the wall-pumping rate is positive. Unless a high net deposition rate (>60%) of hydrocarbon is assumed, the positive wall-pumping rate cannot be explained only by the co-deposition of deuterium with carbon even if the outgassing rate is assumed to be zero. The vessel deuterium inventory decreases by 1.1 × 10 24 on one experimental day with 17 long discharges. The main chamber wall is suggested as the deuterium source for the decrease of the inventory.

Nakano, T.; Asakura, N.; Takenaga, H.; Kubo, H.; Shimizu, K.; Kawashima, H.; JT-60 Team

262

Transient Heat Transport in Subcooled He II Associated with JT Effect  

Microsoft Academic Search

Transient heat transport in subcooled He II has been investigated in a 1 m long rectangular channel with distributed contractions: one-closed end has a heater, while the other end is open to the He II bath. Experiments were conducted applying heat pulses and recording the temperature profile with seven Allan Bradley resistors placed along the channel. Cernox sensor was indium

R. Maekawa; A. Iwamoto; S. Hamaguchi

2004-01-01

263

Development of a hermetically sealed brushless DC motor for a J-T cryocooler  

NASA Technical Reports Server (NTRS)

This development was sponsored by Ball Aerospace for the Cryogenic On-Orbit LongLife Active Refrigerator (COOLLAR) program. The cryocooler is designed to cool objects to 65 K and operate in space for at least 7 years. The system also imports minimal impact to the spacecraft in terms of vibration and heat. The basic Joule-Thompson cycle involves compressing a working fluid, nitrogen in this case, at near-constant temperature from 17.2 KPa to 6.89 MPa. The nitrogen is then expanded through a Joule-Thompson valve. The pure nitrogen gas must be kept clean; therefore, any contamination from motor organic materials must be eliminated. This requirement drove the design towards sealing of the motor within a titanium housing without sacrificing motor performance. It is estimated that an unsealed motor would have contributed 1.65 g of contaminants, due to the organic insulation and potting materials, over the 7-year life. This paper describes the motor electrical and mechanical design, as well as the sealing difficulties encountered, along with their solutions.

Joscelyn, Edwin; Hochler, Irwin; Ferri, Andrew; Rott, Heinz; Soukaris, Ted

1996-01-01

264

Performance deterioration based on simulated aerodynamic loads test, JT9D jet engine diagnostics program  

NASA Technical Reports Server (NTRS)

An engine was specially prepared with extensive instrumentation to monitor performance, case temperatures, and clearance changes. A special loading device was used to apply known loads on the engine by the use of cables placed around the flight inlet. These loads simulated the estimated aerodynamic pressure distributions that occur on the inlet in various segments of a typical airplane flight. Test results indicate that the engine lost 1.3 percent in take-off thrust specific fuel consumption (TSFC) during the course of the test effort. Permanent clearance changes due to the loads accounted for 1.1 percent; increase in low pressure compressor airfoil roughness and thermal distortion in the high pressure turbine accounted for 0.2 percent. Pretest predicted performance loss due to clearance changes was 0.9 percent in TSFC. Therefore, the agreement between measurement and prediction is considered to be excellent.

Stromberg, W. J.

1981-01-01

265

Radiation process of carbon ions in JT-60U detached divertor plasmas  

NASA Astrophysics Data System (ADS)

The spectral lines of C and C emitted around the X-point in the detached plasma with MARFE are measured with a VUV spectrometer and a two-dimensional visible spectrometer in order to compare the generation flux of C (ionization of C and recombination of C) and the loss flux of C (ionization and recombination of C). It has been found that C is produced by the volume recombination of C and the ionization of C comparably. In contrast, the volume recombination of C is not detected, and the ionization flux of C is less than 1% of the C generation flux. Thus, the C generation flux is higher by two orders of magnitude than the loss flux. This result suggests that another loss mechanism of C such as transport loss from the X-point is significant.

Nakano, T.; Kubo, H.; Asakura, N.; Shimizu, K.; Kawashima, H.; Higashijima, S.

2009-06-01

266

Computation of Toroidal-Current Reversal Equilibria for the JT60-U Tokamak  

Microsoft Academic Search

In extreme reversed-shear plasma discharges, the ratio between the poloidal and the toroidal magnetic fields obtained from motional-stark-effect measurements displays significant relative errors inside the core region, with the error bar spanning from small positive values into small negative ones, and therefore magnetic equilibria with toroidal-current reversal cannot be excluded. Following a perturbative approach to solve the Grad-Shafranov equation, a

P. Rodrigues; J. P. S. Bizarro

267

Development of a Low Noise 10K J-T Refrigeration System.  

National Technical Information Service (NTIS)

This report summarizes work done on the development of a low noise, Joule-Thomson, microminiature refrigeration system. Progress has been made on the development of the pneumatic compressor drive system which will be used to operate the compressor to dete...

W. A. Little

1990-01-01

268

Development of a Low Noise 10K J.T. Refrigeration System.  

National Technical Information Service (NTIS)

This report summarizes the results of an engineering design program to develop a low noise, closed cycle, Joule-Thomson, microminiature refrigeration system for 10K operation. During this period the effort has been focused on the fabrication of the argon ...

1986-01-01

269

Development of a Low Noise 10 K J-T Refrigeration System.  

National Technical Information Service (NTIS)

This report summarizes work done on the development of a low noise Joule-Thomson, microminiature refrigeration system design for 10K operation. Good progress has been made on the compressor and on the waterknife to be used for the fabrication of the refri...

W. A. Little

1990-01-01

270

Short-term performance deterioration in JT9D-7A(SP) engine 695743  

NASA Technical Reports Server (NTRS)

The level of performance deterioration that occurred during early service was studied and also the contribution of each engine module to the overall level of engine performance deterioration. To assist in the distribution of the performance losses to the module level, testing with expanded experimental instrumentation was accomplished to permit direct measurement of module performance. An analytical teardown of the engine was accomplished to permit assignment of module performance losses to individual mechanical damage mechanisms including blade and seal wear, roughness, and thermal distortion of turbine parts. The results of the testing show that the engine deteriorated 1.5 percent in thrust specific fuel consumption from its performance when new. Initial testing, which included water washing, showed that 0.2 percent in performance deterioration was due to surface contamination (dirt) and 0.1 percent was due to drift of the engine vane control system, leaving 1.2 percent in basic TSFC deterioration. This 1.2 percent TSFC loss was distributed among the engine modules with 0.6 percent caused by clearance changes, 0.4 percent loss due to thermal distortion, and 0.2 percent loss due to increased roughness of the fan and low-pressure compressor airfoils.

Bouchard, R. J.; Beyerly, W. R.; Sallee, G. P.

1978-01-01

271

Development of a low-noise 10 K J-T (Joule-Thomson) refrigeration system. Technical report (Final)  

SciTech Connect

This report summarizes work done on the development of a low-noise Joule-Thomson, microminiature refrigeration system designed for 10 K operation. Topics discussed include: calculation of phase diagram of mixtures of certain hydrocarbon gases with nitrogen using the Benedict-Webb-Rubin equation of state; the setup of a magnetron-enhanced sputtering system to allow sputtering a layer of adhesive on the glass substrates with a much-better-defined thickness than can be laid down using the older screen printing method; redesign of H/sub 2/ refrigerator test stage, redesign of mixed-gas heat exchanger, refrigerator fabrication, and gas cleaner.

Little, W.A.

1987-06-15

272

Development of a low noise 10K J-T refrigeration system. Technical progress report, 31 Aug-15 Oct 90  

SciTech Connect

This report summarizes work done on the development of a low noise, Joule-Thomson, microminiature refrigeration system. Progress has been made on the development of the pneumatic compressor drive system which will be used to operate the compressor to determine the compressor lifetime and refrigerator system performance. Work on the refrigerator itself also has progressed well with operation down to 20K now being achieved, and reliably reproduced. Work is underway on the heat exchanger section of the third stage of the refrigerator, the helium stage.

Little, W.A.

1990-10-15

273

Hydrogen isotope effects on ITG scale length, pedestal and confinement in JT-60 H-mode plasmas  

NASA Astrophysics Data System (ADS)

The dependence of heat transport, edge pedestal and confinement on isotopic composition was investigated in conventional H-mode plasmas. Identical profiles for the electron density, electron temperature and ion temperature were obtained for hydrogen and deuterium plasmas, whereas the required power clearly increased for hydrogen, which resulted in a reduction in heat diffusivity for deuterium. The determination of identical temperature profiles, despite the different heating power, suggested that the characteristics of heat conduction essentially differ for hydrogen and deuterium, even at the same scale length of temperature gradient. The self-regulating physics mechanism determining the overall H-mode confinement was also addressed. The inverse of the ion temperature gradient (ITG) scale length, or ?Ti/Ti, which is required for a given ion heat diffusivity, increased by a factor of approximately 1.2 for deuterium compared with that for hydrogen. The relationship between edge pedestal pressure and global ?p holds true consistently regardless of the difference in the isotopic composition. A higher value of ?p was obtained for deuterium because of its smaller ITG scale length and because of the additional stored energy in the thermal and fast ion components, the latter due to an increase in the slowing down time with an increase in isotopic mass.

Urano, H.; Takizuka, T.; Aiba, N.; Kikuchi, M.; Nakano, T.; Fujita, T.; Oyama, N.; Kamada, Y.; Hayashi, N.; the JT-60 Team

2013-08-01

274

75 FR 38052 - Airworthiness Directives; Pratt & Whitney JT8D-209, -217, -217A, -217C, and -219 Series Turbofan...  

Federal Register 2010, 2011, 2012, 2013

...217, -217A, -217C, and -219 series turbofan engines. That AD requires initial and...217, - 217A, -217C, and -219 series turbofan engines. These engines are installed...which is whenever the inner turbine fan ducts are removed. Alternative Methods of...

2010-07-01

275

76 FR 16526 - Airworthiness Directives; Pratt & Whitney JT8D-209, -217, -217A, -217C, and -219 Series Turbofan...  

Federal Register 2010, 2011, 2012, 2013

...217, -217A, -217C, and -219 Series Turbofan Engines AGENCY: Federal Aviation Administration...217, - 217A, -217C, and -219 series turbofan engines. These engines are installed...refers to when the inner turbine fan ducts are removed. Alternative Methods of...

2011-03-24

276

75 FR 50945 - Airworthiness Directives; Pratt & Whitney JT8D-209, -217, -217A, -217C, and -219 Turbofan Engines  

Federal Register 2010, 2011, 2012, 2013

...Dargin, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate...this proposed AD. Using the search function of the Web site...TLS of the manufacturer's engine manual for these engines...

2010-08-18

277

Evaluation of two inflow control devices for flight simulation of fan noise using a JT15D engine  

NASA Technical Reports Server (NTRS)

The program was developed to accurately simulate flight fan noise on ground static test stands. The results generally indicated that both the induct and external ICD's were effective in reducing the inflow turbulence and the fan blade passing frequency tone generated by the turbulence. The external ICD was essentially transparent to the propagating fan tone but the induct ICD caused attenuation under most conditions.

Jones, W. L.; Mcardle, J. G.; Homyak, L.

1979-01-01

278

Development of a low-noise 10-K J-T refrigeration system. Technical progress report, 15 August 1986-15 February 1987  

SciTech Connect

This report summarizes work on the development of a low-noise Joule-Thomson, microminiature refrigeration system, designed for 10 K operation. Two events since the last report have had an important influence on the confirmation through a series of experimental measurements of the remarkable cooling power at 80 to 90 K of the nitrogen-hydrocarbon gas mixtures discussed briefly in the previous report. These experiments confirmed that these mixtures could give a refrigeration an order of magnitude greater than that attainable with argon or nitrogen at the same input pressures. In addition, it was recognized that this high efficiency allowed one to use a heat exchanger of substantially smaller surface area and a compressor designed for operation at much lower pressures. This lower-pressure operation would greatly reduce the wear of the piston seals and thereby prolong the life of the system. It was also discovered in the course of these measurements that the use of the gas mixtures resulted in virtually clog-free operation of the refrigerators.

Little, W.A.

1987-02-15

279

A method for estimating the composition of the mixture to be charged to get the desired composition in circulation in a single stage JT refrigerator operating with mixtures  

NASA Astrophysics Data System (ADS)

It has been shown earlier in literature that the composition of the mixture in circulation at steady state is different from that charged into the system in Joule-Thomson refrigerators operating with mixtures. There are no methods in literature that help us charge a particular composition into the system in order to get the desired composition in circulation at steady state. Experiments were performed with 30 different charge compositions, two different heat exchangers, and two different heat loads to understand the relationship between the composition in circulation and that charged. Based on these experiments, a method is proposed for estimating the charge composition required to get the desired composition in circulation.

Lakshmi Narasimhan, N.; Venkatarathnam, G.

2010-02-01

280

Wind tunnel test of model target thrust reversers for the Pratt and Whitney aircraft JT8D-100 series engines installed on a 727-200 airplane  

NASA Technical Reports Server (NTRS)

The results of a low speed wind tunnel test of 0.046 scale model target thrust reversers installed on a 727-200 model airplane are presented. The full airplane model was mounted on a force balance, except for the nacelles and thrust reversers, which were independently mounted and isolated from it. The installation had the capability of simulating the inlet airflows and of supplying the correct proportions of primary and secondary air to the nozzles. The objectives of the test were to assess the compatibility of the thrust reversers target door design with the engine and airplane. The following measurements were made: hot gas ingestion at the nacelle inlets; model lift, drag, and pitching moment; hot gas impingement on the airplane structure; and qualitative assessment of the rudder effectiveness. The major parameters controlling hot gas ingestion were found to be thrust reverser orientation, engine power setting, and the lip height of the bottom thrust reverser doors on the side nacelles. The thrust reversers tended to increase the model lift, decrease the drag, and decrease the pitching moment.

Hambly, D.

1974-01-01

281

TRITIUM-?-DECAY Experiments - the Direct way to the Absolute Neutrino Mass  

NASA Astrophysics Data System (ADS)

Tritium-?-decay experiments provide the most sensitive approach to measure the absolute neutrino mass in a model independent way. The Karlsruhe Tritium Neutrino experiment KATRIN will measure the neutrino mass scale with an expected sensitivity of 0.2 eV/c2 (90% C.L.) and so will help to clarify the roles of neutrinos in the early universe. KATRIN investigates spectroscopically the electron spectrum from tritium ?-decay 3 H -> 3 {He} + {e}^ - + bar ? e close to the kinematic endpoint of 18.6 keV. It will use a windowless gaseous tritium source in combination with an electrostatic filter for energy analysis. KATRIN is currently under construction at the Karlsruhe Institute of Technology (KIT) Campus North. This proceeding will give an overview of the status of the main components of the KATRIN experiment.

Bornschein, Lutz

2013-11-01

282

Detector-related backgrounds in the Karlsruhe Tritium Neutrino Experiment  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino Experiment, or KATRIN, is a next generation tritium beta decay experiment to directly measure neutrino mass with an expected sensitivity of 0.2 eV [KATRIN Design Report 2004 see http://www-ik.fzk.de/~katrin/]. Neutrino mass does not fit into the Standard Model, and determining this mass may set the scale of new physics. To achieve this level of sensitivity, backgrounds in the experiment must be minimized. A complete Geant4 [Agostinelli S et al. 2003 Nuclear Instr. Methods A 506 250-303 Allison J et al. 2006 IEEE Transactions on Nuclear Science53 No. 1 270-8] simulation of KATRIN's focal plane detector and surrounding region is being developed. These simulations will help guide the design and selection of shielding and detector construction materials to reduce backgrounds from cosmic rays and natural radioactivity.

Leber, Michelle; Katrin Collaboration

2011-12-01

283

Study of turbofan engines designed for low energy consumption  

NASA Technical Reports Server (NTRS)

The near-term technology improvements which can reduce the fuel consumed in the JT9D, JT8D, and JT3D turbofans in commercial fleet operation through the 1980's are identified. Projected technology advances are identified and evaluated for new turbofans to be developed after 1985. Programs are recommended for developing the necessary technology.

Gray, D. E.

1976-01-01

284

Jumping translocations in hematological malignancies: a cytogenetic study of five cases.  

PubMed

Jumping translocations (JT) are rare cytogenetic aberrations in hematological malignancies that include unbalanced translocations involving a donor chromosome arm or chromosome segment that has fused to two or more different recipient chromosomes in different cell lines. We report five cases associated with different hematologic disorders and JT to contribute to the investigation of the origin, pathogenesis, and clinical significance of JT. These cases involve JT of 1q in a case of acute myeloblastic leukemia (AML)-M1, a case of Burkitt lymphoma, and a case of BCR/ABL-positive acute lymphoblastic leukemia, as well as a JT of 13q in a case of AML-M5, and a JT of 11q segment in a case of undifferentiated leukemia. To our knowledge, with regard to hematologic malignancies, this study presents the first case of JT associated with AML-M1, the first case of JT involving 13q as a donor chromosome, and the first report of JT involving a segment of 11q containing two copies of the MLL gene, jumping on to two recipient chromosomes in each cell line and resulting in six copies of the MLL gene. Our investigation suggests that JT may not contribute to the pathogenesis but rather to the progression of the disease, and it demonstrates that chromosome band 1q10 as a breakpoint of the donor chromosome 1q is also implicated in AML, not only in multiple myeloma as it has been known until now. PMID:19027489

Manola, Kalliopi N; Georgakakos, Vasileios N; Stavropoulou, Chryssa; Spyridonidis, Alexandros; Angelopoulou, Maria K; Vlachadami, Ioanna; Katsigiannis, Andreas; Roussou, Paraskevi; Pantelias, Gabriel E; Sambani, Constantina

2008-12-01

285

Comment on 'Observations of reconnection of interplanetary and lobe magnetic field lines at the high-latitude magnetopause' by J.T. Gosling, M.F. Thomsen, S.J. Bame, R.C. Elphic, and C.T. Russell  

NASA Technical Reports Server (NTRS)

Comment is presented on the results of measurements, reported by Gosling et al. (1991), that were made on ISEE in the vicinity of the high-latitude dusk magnetopause near the terminator plane, at a time when the local magnetosheath and tail lobe magnetic fields were nearly oppositely directed. The character of the observed plasma flowing both tailward and sunward within the high-latitude magnetopause current layer presented real evidence for the local reconnection process. Gosling et al. argued that this process may be a manifestation of different global magnetospheric topology structures. In the comment, a global magnetospheric convection pattern is constructed for the northward IMF and for the case of a large azimuthal component of the IMF with small Bz, irrespective of its sign. The suggested scheme provides a simple explanation for the observed sunward convection in the polar caps both for the northward and for strong By with small Bz. According to the present model, for the magnetosheath field at 2300 UT on June 11, 1978, the reconnection between the open field lines appears at the northern neutral point.

Belen'kaia, Elena

1993-01-01

286

Improving the performance of small Joule–Thomson cryocooler  

Microsoft Academic Search

This paper presents a new cycle for improving the performance of small Joule–Thomson (JT) cryocooler by applying an additional ejector in cycle system. Based on the presented JT cycle with an additional ejector (JTE), the performance of small JT cryocooler operating with pure N2 and the mixture N2?CH4 for cryogenic applications in a temperature range of 80–130K is investigated by

Jianlin Yu

2008-01-01

287

Direct superconducting pairing versus Jahn–Teller distortions; an analysis of a competition  

Microsoft Academic Search

The competition between a direct, i.e. first-order, superconducting pairing interaction and Jahn–Teller (JT) distortions has been studied theoretically. Finite cluster simulations have been performed for systems which exhibit JT activity or which are pseudo JT active. The first-order pairing employed does not necessarily involve second-order elements such as the electron–phonon coupling or specific magnetic interactions. The pairing is defined only

Michael C. Böhm; Joachim Schulte

2004-01-01

288

Helium liquefaction using cryorefrigerators  

Microsoft Academic Search

A two-stage Gifford-McMahon refrigerator with a Joule-Thomson (J-T) stage connected in series, was extended to a small helium liquefier. The plant can operate automatically. Helium is liquefied within the J-T cycle, directly after the J-T valve, into a 3l tank. This liquid He is used for the indirect cooling of an externally accessible sample chamber, either by using helium contact

Hans-Joachim Forth

1986-01-01

289

Paraveterinary service use in Nepal's Himalaya.  

PubMed

The involvement of paraveterinarians in animal-health delivery can reduce costs and allow expanded service delivery. Our objectives were to describe use of public paraveterinary services offered by junior technicians (JT) in two regions of Nepal, to identify factors associated with JT service use, and to characterize factors that limit JT service use. We used a survey of livestock owners in the Khumbu and Lower Mustang regions of Nepal's Himalaya to examine JT service use. Of 118 questionnaires completed between May 30, 1997 and July 8, 1997, 81 were analyzed for use of JT services to treat livestock: bovids, equids, and small ruminants. Five factors were associated with owners' use of JT services: living <30 min walk from a JT post (OR=12.2); having a positive opinion about JT services (OR=23.6); animals not having disease events that either impaired mobility or affected production or reproduction (OR=5.6), animals died related to a reported disease event (OR=3.2), and the owners' sex (with women being more likely to report use of JT services than men; OR=5.3). PMID:20371125

Marshall, Edith S; Sischo, William M

2010-06-01

290

Analysis of a tobacco vector and its actions in china: the activities of japan tobacco  

PubMed Central

Japan Tobacco (JT) is the third largest tobacco company in the world, and China, the world's largest tobacco consumer, is one of the most important targets for JT. To provide information for tobacco control, we reviewed and analyzed JT and its tactics and strategies in the Chinese market mainly by systematic examination of documents which are made available in the University of California, San Francisco Legacy Tobacco Documents Library. As a result, JT has had a special interest to expand sales of its cigarettes in the Chinese market.

2010-01-01

291

A Unique Jahn-Teller Mechanism of all the Symmetry Breakings in Molecular Systems and Condensed Matter  

NASA Astrophysics Data System (ADS)

An attempt is made to present all the symmetry breakings (SB) in molecular systems and condensed matter from a unique point of view as controlled by the electronic structure, degeneracy and pseudodegeneracy, via the Jahn-Teller (JT) vibronic coupling effects [JT, Renner-Teller (RT), and pseudo Jahn-Teller (PJT) effects]. For chemically bonded systems in high-symmetry configurations and transition states of chemical reactions, as proved earlier, the JT effects are the only possible source of spontaneous distortion, which is the necessary condition of SB. It is shown that the JT (and related RT and PJT) effects are directly applicable to chemically nonbonded systems: formation of molecules from atoms (chemical bonding), as well as intermolecular interaction, can be regarded as particular cases of JT effects. This closes the gap in considering all the SB in molecular systems as triggered by JT effects. It stimulated also a general (extended and more rigorous) formulation of the JT theorem to include all the vibronic coupling effects and recent achievements in the JT effect theory. Added to the JT origin of structural phase transitions and liquid-solid transition, considered earlier, and gas-liquid transition shown to be in principle of the same JT origin, the results above lead us to a general conclusion that spontaneous SB in molecular systems and condensed matter are always associated with degeneracy or pseudodegeneracy and realized via JT vibronic coupling effects. Together with the concept of SB in particle physics as associated with degeneracy, we can speculate about a general picture of consecutive transformations of matter via similar in nature degeneracy-based SB, beginning with the Big Bang.

Bersuker, Isaac B.

292

Karlsruhe Tritium Experiment: Detector System Commissioning and In-Situ PIN-Diode Array Dead-Layer Measurement  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino (KATRIN) experimental goal is to measure the neutrino mass to 0.2 eV sensitivity at the 90 percent confidence level. This is an order of magnitude more sensitive than the two most recent direct neutrino mass measurements. The primary sensitivity of the KATRIN experiment is determined by the source strength and the main spectrometer resolution, but a confluence of focal plane detector parameters contribute to the uncertainty in the measured neutrino mass including the detector backgrounds and the detector electron response function. The detector system group developed a figure of demerit, F, to quantify the effect of the detector system on neutrino mass uncertainty. F, essentially a signal to noise ratio, weights the focal plane detector response function against the total background based upon their influence of the m2n uncertainty. During commissioning of the detector system at the University of Washington, we determined a figure of demerit value of 1.12 +/- .01, which nearly meets the tritium data taking goal for KATRIN. A critical parameter that effects the detector response is the focal plane detector's dead layer. The KATRIN detector system's design constraints needed a novel approach to measure the dead-layer thickness not outlined in standard texts. We used a method of making measurements with an electron source over a range of incident energies, and then fit these monoenergetic electron source spectra to simulated spectra to determine the dead-layer thickness of the KATRIN focal plane detector. The standard model of a monolithic dead layer yielded poor overall fits, while a model that allowed the energy deposited into the dead layer to diffuse back into the active region, gave an improved fit, with a preferred value of 46%. Using this model, the final detector dead layer thickness of the focal plane detector is 1554 +/- 5+18.8-12.4 A.

Wall, Brandon Lee

293

14 CFR 36.1 - Applicability and definitions.  

Code of Federal Regulations, 2010 CFR

...except for airplanes that are powered by Pratt & Whitney Turbo Wasp JT3D series engines; (ii) December 31, 1974, for airplanes...75,000 pounds and that are powered by Pratt & Whitney Turbo Wasp JT3D series engines; and (iii) December 31, 1974,...

2010-01-01

294

14 CFR 36.1 - Applicability and definitions.  

Code of Federal Regulations, 2010 CFR

...except for airplanes that are powered by Pratt & Whitney Turbo Wasp JT3D series engines; (ii) December 31, 1974, for airplanes...75,000 pounds and that are powered by Pratt & Whitney Turbo Wasp JT3D series engines; and (iii) December 31, 1974,...

2009-01-01

295

Thermodynamic optimization of sorption-based Joule–Thomson coolers  

Microsoft Academic Search

A cooler consisting of a sorption compressor with a Joule–Thomson (JT) cold stage has several advantages. These coolers have no moving parts which is attractive for a variety of reasons. Unfortunately, the efficiency of sorption-based JT coolers is in many cases relatively small. This paper presents a thermodynamic description of the compressor and the cold stage separately. Their efficiencies are

G. F. M. Wiegerinck; H. J. M. ter Brake; J. F. Burger; H. J. Holland; H. Rogalla

2007-01-01

296

Construction of new cloning, lacZ reporter and scarless-markerless suicide vectors for genetic studies in Aggregatibacter actinomycetemcomitans.  

PubMed

To elucidate the putative function of a gene, effective tools are required for genetic characterization that facilitate its inactivation, deletion or modification on the bacterial chromosome. In the present study, the nucleotide sequence of the Escherichia coli/Aggregatibacter actinomycetemcomitans shuttle vector pYGK was determined, allowing us to redesign and construct a new shuttle cloning vector, pJT4, and promoterless lacZ transcriptional/translational fusion plasmids, pJT3 and pJT5. Plasmids pJT4 and pJT5 contain the origin of replication necessary to maintain shuttle vector replication. In addition, a new suicide vector, pJT1, was constructed for the generation of scarless and markerless deletion mutations of genes in the oral pathogen A. actinomycetemcomitans. Plasmid pJT1 is a pUC-based suicide vector that is counter-selectable for sucrose sensitivity. This vector does not leave antibiotic markers or scars on the chromosome after gene deletion and thus provides the option to combine several mutations in the same genetic background. The effectiveness of pJT1 was demonstrated by the construction of A. actinomycetemcomitans isogenic qseB single deletion (?qseB) mutant and lsrRK double deletion mutants (?lsrRK). These new vectors may offer alternatives for genetic studies in A. actinomycetemcomitans and other members of the HACEK (Haemophilus spp., A. actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) group of Gram-negative bacteria. PMID:23353051

Juárez-Rodríguez, María Dolores; Torres-Escobar, Ascención; Demuth, Donald R

2013-05-01

297

Engine component improvement program: Performance improvement. [fuel consumption  

NASA Technical Reports Server (NTRS)

Fuel consumption of commercial aircraft is considered. Fuel saving and retention components for new production and retrofit of JT9D, JT8D, and CF6 engines are reviewed. The manner in which the performance improvement concepts were selected for development and a summary of the current status of each of the 16 selected concepts are discussed.

Mcaulay, J. E.

1979-01-01

298

100KV, 80A, 10S Power Supply for a Neutral Beam Injector Using a Series of Gate Turn off Thyristors as a Regulator/Switch Valve.  

National Technical Information Service (NTIS)

A voltage regulated GTO valve was devised and applied in the accel power supply of the prototype injector unit for JT-60 with the particular intent to check its applicability to the JT-60 NBI power supplies. High reliability and applicability were confirm...

M. Matsuoka M. Kawai M. Komata S. Kitamura S. Matsuda

1984-01-01

299

Joule-Thomson inversion curves of mixtures by molecular simulation in comparison to advanced equations of state: natural gas as an example  

Microsoft Academic Search

Molecular modelling and simulation as well as four equations of state (EOS) are applied to natural gas mixtures regarding Joule-Thomson (JT) inversion. JT inversion curves are determined by molecular simulation for six different natural gas mixtures consisting of methane, nitrogen, carbon dioxide and ethane. These components are also regarded as pure fluids, leading to a total of ten studied systems.

J. Vrabec; A. Kumar; H. Hasse

2009-01-01

300

Joule–Thomson inversion curves of mixtures by molecular simulation in comparison to advanced equations of state: Natural gas as an example  

Microsoft Academic Search

Molecular modelling and simulation as well as four equations of state (EOS) are applied to natural gas mixtures regarding Joule–Thomson (JT) inversion. JT inversion curves are determined by molecular simulation for six different natural gas mixtures consisting of methane, nitrogen, carbon dioxide and ethane. These components are also regarded as pure fluids, leading to a total of 10 studied systems.

Jadran Vrabec; Ashish Kumar; Hans Hasse

2007-01-01

301

Interplay between Coulomb and Jahn-Teller effects in icosahedral systems with triplet electronic states coupled to h-type vibrations  

NASA Astrophysics Data System (ADS)

We will consider the role played by electron-vibration and electron-electron interactions, through Jahn-Teller (JT) and Coulomb interactions, respectively, in icosahedral systems in which triplet electronic states are coupled to hg-type vibrations. Starting from the electronic terms that arise from consideration of Coulomb interactions, we introduce JT couplings both within the terms and between nondegenerate terms. We show how the symmetry of the JT distortion can change when extra electrons are added, and give the conditions under which JT distortions can be suppressed entirely when the Coulomb interactions are sufficiently large. The relevance of our results to anions of the fullerene molecule C60 are briefly discussed, and existing experimental measurements are used to estimate values for the quadratic JT coupling constants for these anions.

Alqannas, Haifa S.; Lakin, Andrew J.; Farrow, Joseph A.; Dunn, Janette L.

2013-10-01

302

A miniature Joule-Thomson cooler for optical detectors in space.  

PubMed

The utilization of single-stage micromachined Joule-Thomson (JT) coolers for cooling small optical detectors is investigated. A design of a micromachined JT cold stage-detector system is made that focuses on the interface between a JT cold stage and detector, and on the wiring of the detector. Among various techniques, adhesive bonding is selected as most suitable technique for integrating the detector with the JT cold stage. Also, the optimum wiring of the detector is discussed. In this respect, it is important to minimize the heat conduction through the wiring. Therefore, each wire should be optimized in terms of acceptable impedance and thermal heat load. It is shown that, given a certain impedance, the conductive heat load of electrically bad conducting materials is about twice as high as that of electrically good conducting materials. A micromachined JT cold stage is designed and integrated with a dummy detector. The JT cold stage is operated at 100 K with nitrogen as the working fluid and at 140 K with methane. Net cooling powers of 143 mW and 117 mW are measured, respectively. Taking into account a radiative heat load of 40 mW, these measured values make the JT cold stage suitable for cooling a photon detector with a power dissipation up to 50 mW, allowing for another 27 to 53 mW heat load arising from the electrical leads. PMID:22559586

Derking, J H; Holland, H J; Tirolien, T; ter Brake, H J M

2012-04-01

303

Clogging of Joule-Thomson Devices in Liquid Hydrogen-Lunar Lander Descent Stage Operating Regime  

NASA Astrophysics Data System (ADS)

Joule-Thomson (J-T) devices have been identified as critical components for future space exploration missions. The NASA Constellation Program lunar architecture considers LOX/LH2 propulsion for the lunar lander descent stage main engine an enabling technology, ensuring the cryogenic propellants are available at the correct conditions for engine operation. This cryogenic storage system may utilize a Thermodynamic Vent System (TVS) that includes J-T devices to maintain tank fluid pressure and temperature. Previous experimental investigations have indicated that J-T devices may become clogged when flowing LH2 while operating at a temperature range from 20.5 K to 24.4 K. It has been proposed that clogging is due to a trace amount of metastable, supercooled liquid neon in the regular LH2 supply. In time, flow blockage occurs from accretion of solid neon on the orifice. This clogging poses a realistic threat to spacecraft propulsion systems utilizing J-T devices in cryogenic pressure control systems. TVS failure due to J-T clogging would prevent removal of environmental heat from the propellant and potential loss of mission. This report describes J-T clogging tests performed with LH2. Tests were performed in the expected Lunar Lander operating regime, and several methods were evaluated to determine the optimum approach to mitigating the potential risk of J-T clogging.

Jurns, J. M.

2010-04-01

304

Mixed refrigerant Joule-Thomson sorption cryocoolers  

NASA Astrophysics Data System (ADS)

Joule-Thomson (JT) sorption cryocooling is the most mature technology for cooling from a normal Room-Temperature (RT) down to temperatures below 100 K in the absence of moving parts. Therefore, high reliability and no vibrations are attainable, in comparison with other cryocoolers. Cooling to 80 - 100 K with JT cryocoolers is often implemented with pure nitrogen. Alternatively, mixed refrigerants have been suggested for reducing the operating pressures to enable closed cycle cryocooling. There is a variety of publications describing nitrogen sorption cryocoolers with different configurations of sorption compressors. In the present research we suggest a novel sorption JT cryocooler that operates with a mixed refrigerant. Merging of sorption cryocooling and a mixed refrigerant enables the use of a simple, single stage compressor for cooling to 80 - 100 K, lower operating temperatures of the sorption cycle, and thus - reduced power consumption. In previous studies we have analyzed sorption compressors for mixed gases and mixed refrigerants for JT cryocoolers, separately. In this paper the option of mixed refrigerant sorption JT cryocoolers is explored. The considerations for developing mixed refrigerants to be driven by sorption compressors and to be utilized with JT cryocoolers are provided. It appears that, unlike with pure nitrogen, mixed refrigerants can be suitable for JT cryocooling with a single stage sorption compressor.

Tzabar, Nir; Grossman, Gershon

2014-01-01

305

Charge localization and Jahn-Teller distortions in the benzene dimer cation  

NASA Astrophysics Data System (ADS)

Jahn-Teller (JT) distortions and charge localization in the benzene dimer cation are analyzed using the equation-of-motion coupled cluster with single and double substitutions for ionization potential (EOM-IP-CCSD) method. Ionization of the dimer changes the bonding from noncovalent to covalent and induces significant geometrical distortions, e.g., shorter interfragment distance and JT displacements. Relaxation along interfragment coordinates lowers the energy of the t-shaped and displaced sandwich isomers by 0.07 and 0.23 eV, respectively, whereas JT displacements result in additional 0.18 and 0.23 eV. Energetically, the effect of JT distortion on the dimer is similar to the monomer where JT relaxation lowers the energy by 0.18 eV. While the change in the interfragment distance has dramatic spectroscopic consequences, the JT distortion causes only a small perturbation in the electronic spectra. The two geometrical relaxations in the t-shaped isomer lead to opposing effects on hole localization. Intermolecular relaxation leads to an increased delocalization, whereas JT ring distortion localizes the charge. In the sandwich isomers, breaking the symmetry by ring rotation does not induce considerable charge localization. The optimization and property calculations were performed using a new implementation of EOM-IP-CCSD energies and gradients in the Q-CHEM electronic structure package.

Pieniazek, Piotr A.; Bradforth, Stephen E.; Krylov, Anna I.

2008-08-01

306

A miniature Joule-Thomson cooler for optical detectors in space  

NASA Astrophysics Data System (ADS)

The utilization of single-stage micromachined Joule-Thomson (JT) coolers for cooling small optical detectors is investigated. A design of a micromachined JT cold stage-detector system is made that focuses on the interface between a JT cold stage and detector, and on the wiring of the detector. Among various techniques, adhesive bonding is selected as most suitable technique for integrating the detector with the JT cold stage. Also, the optimum wiring of the detector is discussed. In this respect, it is important to minimize the heat conduction through the wiring. Therefore, each wire should be optimized in terms of acceptable impedance and thermal heat load. It is shown that, given a certain impedance, the conductive heat load of electrically bad conducting materials is about twice as high as that of electrically good conducting materials. A micromachined JT cold stage is designed and integrated with a dummy detector. The JT cold stage is operated at 100 K with nitrogen as the working fluid and at 140 K with methane. Net cooling powers of 143 mW and 117 mW are measured, respectively. Taking into account a radiative heat load of 40 mW, these measured values make the JT cold stage suitable for cooling a photon detector with a power dissipation up to 50 mW, allowing for another 27 to 53 mW heat load arising from the electrical leads.

Derking, J. H.; Holland, H. J.; Tirolien, T.; ter Brake, H. J. M.

2012-04-01

307

Education for Engineers in Mitsubishi Heavy Industries  

NASA Astrophysics Data System (ADS)

In manufacturing companies, the importance of Off the Job Training (OffJT) is increasing, because there are not enough opportunities for On the Job Training (OJT) . Therefore, OffJT is required to further improve quality. Also it is required to enhance the skills of our engineers, as a substitute for OJT. Mitsubishi Heavy Industries has improved OffJT by using the same methods of quality improvement as those employed in our factories. It has also developed exercises to train engineers in complex multiple skills, thus improving their ability. We report the results of these efforts.

Ohsone, Masanori; Funakoshi, Makoto; Taguchi, Toshio

308

The first phase of the MARE project in Milano  

NASA Astrophysics Data System (ADS)

The international project "Microcalorimeter Arrays for a Rhenium Experiment" (MARE) aims at the direct and calorimetric measurement of the electron anti-neutrino mass with sub-electronvolt sensitivity. The experimental strategy consists in studying the beta spectrum of 187Re near the end-point looking for the spectral distortion expected for a finite anti-neutrino mass. The MARE project has a staged approach: in the final experimental phase (MARE-2), several large arrays with as many as 10 000 detectors each will be deployed to collect the statistics required to probe the anti-neutrino mass with a sensitivity of at least 0.2 eV, comparable to the one expected for the Katrin experiment (KATRIN LoI, 2001, [1]). In the short term, smaller scale experiments are planned to reach sensitivities of the order of 1 eV (MARE-1). This contribution reports on the Milano group activity for the MARE project.

Nucciotti, A.; Arnaboldi, C.; Ceruti, G.; Ferri, E.; Kilbourne, C.; Kraft-Bermuth, S.; Margesin, B.; Pessina, G.; Previtali, E.; Schaeffer, D.; Sisti, M.

2010-05-01

309

Performance of a TiN-coated monolithic silicon pin-diode array under mechanical stress  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino Experiment (KATRIN) will detect tritium ?-decay electrons that pass through its electromagnetic spectrometer with a highly segmented monolithic silicon pin-diode focal-plane detector (FPD). This pin-diode array will be on a single piece of 500-?m-thick silicon, with contact between titanium nitride (TiN)-coated detector pixels and front-end electronics made by spring-loaded pogo pins. The pogo pins will exert a total force of up to 50 N on the detector, deforming it and resulting in mechanical stress up to 50 MPa in the silicon bulk. We have evaluated a prototype pin-diode array with a pogo-pin connection scheme similar to the KATRIN FPD. We find that pogo pins make good electrical contact to TiN and observe no effects on detector resolution or reverse-bias leakage current which can be attributed to mechanical stress.

VanDevender, B. A.; Bodine, L. I.; Myers, A. W.; Amsbaugh, J. F.; Howe, M. A.; Leber, M. L.; Robertson, R. G. H.; Tolich, K.; Van Wechel, T. D.; Wall, B. L.

2012-05-01

310

Neutrino mass and extreme value distributions in ?-decay  

NASA Astrophysics Data System (ADS)

We propose to apply the Extreme Value Theory for distributions with compact support to the estimation of the neutrino mass from the energy spectrum of electrons in ?-decay. Using these techniques the dependence of the results on the mass of the neutrino is considerably enhanced increasing the sensitivity of the experiment. We discuss how these tools could be applied to the present proposals like the KATRIN experiment.

Esteve, J. G.; Falceto, Fernando

2014-05-01

311

Polymers from plants to develop biodegradable plastics.  

PubMed

Katrin Neumann et al. have recently shown that transgenic tobacco and potato plants can accumulate high levels of cyanophycin, a possible source for poly-aspartate. This work opens the way to the future production of biodegradable plastics using a plant-based production system. Several problems need to be overcome first, such as growth retardation as a result of cyanophycin accumulating in the cytosol, and a co-production system needs to be developed for economical reasons. PMID:16213779

Conrad, Udo

2005-11-01

312

Discretionary Review by the Occupational Safety and Health Review Commission: Is It Necessary?  

ERIC Educational Resources Information Center

Deficiencies in the Occupational Safety and Health Review Commission (OSAHRC), a court system created to carry out adjudicatory functions under the Williams-Steiger Occupational Safety and Health Act of 1970, are exposed and alternative solutions offered. (JT)

Moran, Robert D.

1974-01-01

313

Mixed Refrigerants for a Glass Capillary Micro Cryogenic Cooler.  

National Technical Information Service (NTIS)

Optimized mixed refrigerants are applied in Joule-Thomson (JT) micro cryogenic coolers (MCC) to enhance efficiency. Mixed refrigerants deliver equivalent refrigeration power with much lower pressure ratio and flow rate compared to pure nitrogen refrigeran...

M. H. Lin M. L. Huber P. E. Bradley R. Lewis R. Radebaugh

2010-01-01

314

Test results after refurbish of cryogenic system for smiles  

NASA Astrophysics Data System (ADS)

Superconducting Sub-millimeter-wave Limb-Emission Sounder (SMILES) is to be operated aboard the Japanese Experiment Module (JEM) of the International Space Station (ISS) in 2009. SMILES uses two superconductor-insulator-superconductor (SIS) mixers for sub-millimeter-wave atmospheric observation and they are cooled to 4 K levels by a cryogenic system with a two-stage Stirling cooler, a Joule-Thomson (JT) cycle cooler and a cryostat composed of three stages. Two-stage Stirling cooler precools the JT circuit and also cools radiation shields in the cryostat. JT circuit has three tube-in-tube type heat exchangers and an orifice for JT expansion in the cryostat. The cryogenic system is built, tested and delivered.

Otsuka, Kiyomi; Tsunematsu, Shoji; Okabayashi, Akinobu; Narasaki, Katsuhiro; Satoh, Ryota

2010-09-01

315

Wardenly Role; The Academic Presence in University Residence  

ERIC Educational Resources Information Center

Examines the whole range of student personnel and counseling services in one British university with special attention to the residential element. Compares results, particularly attitudes of wardens (residence counselors) toward their role, to those of earlier studies. (JT)

Pashley, Barry; Shepherd, Angela

1975-01-01

316

Gingivostomatitis  

MedlinePLUS

... children. It may occur after infection with the herpes simplex virus type 1 (HSV-1), which also causes ... Schiffer JT, Corey L. Herpes simplex virus. In: Mandell GL, Bennett ... of Infectious Diseases . 7th ed. Philadelphia, Pa: Elsevier ...

317

Cool's Clams Casino  

ERIC Educational Resources Information Center

A mathematical game that reinforces basic multiplication facts, strengthens concepts of factors and multiples, and also provides arithmetic drill is described. Four variations of the game are also provided. (JT)

Cobey, Paul; Williams, David E.

1977-01-01

318

75 FR 66138 - George Mathew, M.D.; Denial of Application  

Federal Register 2010, 2011, 2012, 2013

...Respondent is board-certified in internal medicine and holds a medical license...office-based family and internal medicine group practice.'' Jt. Ex...holds board certification in internal medicine, is a fellow of the...

2010-10-27

319

Flight effects of fan noise  

NASA Technical Reports Server (NTRS)

Simulation of inflight fan noise and flight effects was discussed. The status of the overall program on the flight effects of fan noise was reviewed, and flight to static noise comparisons with the JT15D engine were displayed.

Chestnutt, D. (editor)

1982-01-01

320

Exploration of Home Economics Related Occupations in Clothing  

ERIC Educational Resources Information Center

A five-unit lesson plan is presented titled "Introduction to Careers in the Fashion Industry" which involved three sections of a ninth grade home economics class in an assembly line sewing experience in a clothing production factory. (JT)

Thomas, Virginia F.; Plumb, Sandra

1976-01-01

321

Electronic Warfare Test. Interim Report Phase 3.  

National Technical Information Service (NTIS)

The Joint Advanced Distributed Simulation (JADS) Joint Test and Evaluation (JT&E) was chartered by the Deputy Director, Test, Systems Engineering and Evaluation (Test and Evaluation), Office of the Secretary of Defense (Acquisition and Technology) in Octo...

D. L. Wright R. M. Nation

1999-01-01

322

Air-to-Air Missile Testing Using Advanced Distributed Simulation.  

National Technical Information Service (NTIS)

The Joint Advanced Distributed Simulation Joint Test and Evaluation (JADS JT&E) was chartered by the Deputy Director, Test, Systems Engineering and Evaluation (Test and Evaluation), Office of the Under Secretary of Defense (Acquisition and Technology) in ...

L. McKee

1996-01-01

323

JADS Special Report on Programmatic Challenges to Distributed Testing.  

National Technical Information Service (NTIS)

The Joint Advanced Distributed Simulation Joint Test and Evaluation (JT&E) was chartered by the Deputy Director, Test, Systems Engineering and Evaluation (Test and Evaluation), Office of the Secretary of Defense (0SD) (acquisition and Technology) in Octob...

J. M. McCall J. Reeves L. McKee

1999-01-01

324

Glass Walls.  

ERIC Educational Resources Information Center

Relates some of the author's experiences while teaching on the Pine Ridge (South Dakota) Sioux Reservation, showing how learning barriers can be broken with a little understanding between teacher and students. (JT)

Smith, Jeanne A.

1980-01-01

325

Theory of the Antiferroorbital Ordering Due to the Cooperative Jahn Teller Effect  

NASA Astrophysics Data System (ADS)

The antiferroorbital ordering, i.e., the antiparallel ordering of electronic orbitals, in compounds is studied theoretically on the basis of the cooperative Jahn Teller (JT) effect by use of a static approximation. The Hamiltonian consists of the JT coupling to all distortion modes and the higher order terms, i.e., the anharmonic lattice energy and the second-order JT coupling. By taking account of the crystal symmetry, the theory can determine uniquely the equilibrium antiferroorbital state accompanied by the JT distortions. It is found that the transition of the antiferroorbital phase can become of the first order for large higher order terms. The properties of the elastic softening in the antiferroorbital state are clarified and compared with those in the ferroorbital state. The theory explains successfully the antiferrodistortion and the ferrodistortion coexisting in MnF3 and KCuF3.

Kataoka, Mitsuo

2001-08-01

326

ENVIRONMENTAL IMPACTS AND MONITORING: A HISTORICAL PERSPECTIVE ON THE USE OF NATURAL ATTENUATION FOR SUBSURFACE REMEDIATION: BOOK CHAPTER  

EPA Science Inventory

BOOK CHAPTER NRMRL-ADA-01128 West, CC, and Wilson*, J.T. "Environmental Impacts and Monitoring: A Historical Perspective on the Use of Natural Attenuation for Subsurface Remediation." In: Environmental Chemistry: Fate, ...

327

Evidence-Based Cognitive Rehabilitation: Updated Review of the Literature From 1998 Through 2002  

Microsoft Academic Search

Cicerone KD, Dahlberg C, Malec JF, Langenbahn DM, Felicetti T, Kneipp S, Ellmo W, Kalmar K, Giacino JT, Harley JP, Laatsch L, Morse PA, Catanese J. Evidence-based cognitive rehabilitation: updated review of the literature from 1998 through 2002.

Keith D. Cicerone; Cynthia Dahlberg; James F. Malec; Donna M. Langenbahn; Thomas Felicetti; Sally Kneipp; Wendy Ellmo; Kathleen Kalmar; Joseph T. Giacino; J. Preston Harley; Linda Laatsch; Philip A. Morse; Jeanne Catanese

2005-01-01

328

Consumer-Homemaking for Teenage Parents  

ERIC Educational Resources Information Center

Describes a successful Jefferson County, Georgia, pilot program for teenage parents. The program for male and female high school students includes a counseling component and curriculum focus on prenatal-postnatal care, child care and development, and health services. (JT)

Webb, Jackie Roger; Edenfield, Myrtice

1977-01-01

329

Where Have All the Immigrants Gone?  

ERIC Educational Resources Information Center

Traces the history of the "compulsory-cure" model of United States education (in which students are assumed to need "curing") that is currently in use. Notes the problems caused by accepting and perpetuating this educational model. (JT)

Otten, Nick

1980-01-01

330

Dissociation between androgen responsiveness for malignant growth vs. expression of prostate specific differentiation markers PSA, hK2, and PSMA in human prostate cancer models. Denmeade SR, Sokoll LJ, Dalrymple S, Rosen DM, Gady AM, Bruzek D, Ricklis RM, Isaacs JT, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21231  

Microsoft Academic Search

A detailed understanding is evolving as to how androgen receptor (AR) functions as a transcriptional regulator via its binding to androgen response elements (ARE) within promoter and enhancer regions of prostate-specific differentiation markers such as PSA, hK2, and PSMA. It has been assumed that an understanding of regulation of expression of these marker proteins would also provide an understanding of

Maarten Bosland

2003-01-01

331

Non-cubic distortions in quadratic E?e Jahn-Teller systems  

Microsoft Academic Search

We investigate the E?e Jahn-Teller (JT) system when both linear and quadratic couplings are included and when it is subjected to external symmetry-lowering distortions. Such distortions could, for example, be due to intrinsic molecular geometry, strains applied to a cubic crystal, and as the result of cooperative interactions between different JT centers. It is well known that the lowest adiabatic

Elie A. Moujaes; Janette L. Dunn; Colin A. Bates

2008-01-01

332

Optimization of the working fluid in a Joule–Thomson cold stage  

Microsoft Academic Search

Vibration-free miniature Joule–Thomson (JT) coolers are of interest for cooling a wide variety of devices, including low-noise amplifiers, semiconducting and superconducting electronics, and small optical detectors used in space applications. For cooling such devices, coolers are needed which have operating temperatures within a wide temperature range of 2–250K. In this paper, the optimization of the working fluid in JT cold

J. H. Derking; H. J. M. ter Brake; A. Sirbi; M. Linder; H. Rogalla

2009-01-01

333

Performance evaluation of the recuperative heat exchanger in a miniature Joule–Thomson cooler  

Microsoft Academic Search

To develop effective heat exchangers for miniature and micro-Joule–Thomson (J–T) cooling system, the performance of the recuperative heat exchanger in a miniature J–T cooler is analyzed and evaluated. The evaluation is based on a theoretical model of the Hampson-type counter-flow heat exchanger. The effect of the pressure and temperature-dependent properties and longitudinal heat conduction are considered. The results of the

H. Xue; K. C. Ng; J. B. Wang

2001-01-01

334

Experimental investigation on mixed refrigerant Joule–Thomson cryocooler with flammable and non-flammable refrigerant mixtures  

Microsoft Academic Search

The mixed refrigerant Joule–Thomson (MR J–T) cryocoolers have a wide application area covering the temperature range from 80K to 200K. The significant advantages of the system are simplicity of its design and working reliability with high level performance. The present paper discusses the experimental results of MR J–T cooler with different flammable and non-flammable mixture compositions. The work highlights the

N. S. Walimbe; K. G. Narayankhedkar; M. D. Atrey

2010-01-01

335

STUDY OF BEHAVIOR IN THE HEAT EXCHANGER OF A MIXED GAS JOULE-THOMSON COOLER  

Microsoft Academic Search

The object of the investigation is a mixed gas Joule-Thomson (J-T) cooler. A computa- tional model was developed, which makes it possible to investigate the steady state behavior of the refrigerant in the heat exchanger of a mixed gas J-T system. The calculations show that the temperature distribution as well as the pressure distribution in the heat exchanger channels depends

A. Alexeev; A. Thiel; Ch. Haberstroh; H. Quack

336

Development of a Piezoelectric Microcompressor for a Joule Thomson Microcryocooler  

Microsoft Academic Search

In this paper we discuss the development of a microcompressor (MC) theoretically capable of delivering pressure ratios from 16:1 to 25:1 for design flow rates, of about 0.15 std. cm 3 \\/s, intended to provide flow for a mixed refrigerant Joule-Thomson (J-T) microcryocooler. The J-T microcryocooler supports on-chip cooling applications, such as terahertz and infrared imaging sen- sors operating at

M. J. Simon; C. DeLuca; Y. C. Lee; P. E. Bradley; R. Radebaugh

337

Test-engine and inlet performance of an aircraft used for investigating flight effects on fan noise  

Microsoft Academic Search

As part of the NASA Flight Effects on Fan Noise Program, a Grumman OV-1B Mohawk aircraft was modified to carry a modified and instrumented Pratt & Whitney JT15D-1 turbofan engine. Onboard flight data, together with simultaneously measured farfield acoustic data, comprise a flight data base to which JT15D-1 static and wind-tunnel data are compared. The overall objective is to improve

R. A. Golub; J. S. Preisser

1984-01-01

338

Local Structure of La1-xSrxCoO3 determined from EXAFS and neutron PDF studies  

SciTech Connect

The combined local structure techniques, extended x-ray absorption fine structure (EXAFS) and neutron pair distribution function analysis, have been used for temperatures 4<= T<= 330 K to rule out a large Jahn-Teller (JT) distortion of the Co-O bond in La1?xSrxCoO3 for a significant fraction of Co sites (x<= 0.35), indicating few, if any, JT-active, singly occupied eg Co sites exist.

Sundaram, N.; Jiang, Y.; Anderson, I. E.; Belanger, D. P.; Booth, C. H.; Bridges, F.; Mitchell, J. F.; Proffen, Th.; Zheng, H.

2009-01-26

339

Development of a High Field Superconducting Magnet Cooled by a 2 K Cryocooler (2) - Characteristics of 2 K Cryocooler  

Microsoft Academic Search

This paper describes the experimental results of a small 2 K Gifford-McMahon\\/Joule-Thomson type (GM\\/JT) cryocooler, which was used to cool a high-field superconducting magnet. We improved efficiency of the 2 K cryocooler by using a double Joule-Thomson (JT) valve. We also adopted a high capacity compressor to obtain over 1 W cooling capacity at 1.8 K. To reduce the cooling

A. Sato; S. Nimori; M. Maeda; H. Nagai; F. Matsumoto; M. Takahashi; T. Kuriyama; T. Fujioka; T. Ito; T. Okamura

2004-01-01

340

Wafer-level processing for polymer-based planar micro cryogenic coolers  

Microsoft Academic Search

In this paper, we present the fabrication and testing of a novel polymer-based Joule-Thomson (J-T) micro cryogenic cooler (MCC). Techniques including monolithic fabrication of high pressure polymer channels and 3-D interconnect for fluid channels including a flow resistance are developed to fabricate a planar MCC. The MCC contains a polymer heat exchanger and a silicon\\/glass J-T valve. A low temperature

Y. D. Wang; R. Lewis; M.-H. Lin; R. Radebaugh; Y. C. Lee

2012-01-01

341

Performance Investigations of a 4 to 10 K Long-Life Mechanical Cryocooler  

Microsoft Academic Search

We believe that the quickest way of obtaining a reliable space cooler in the range of 4 to 10 K is to combine a Stirling mechanical cooler with a Joule-Thomson (J-T) cooler. In this approach we perform the bulk of the cooling with the Stirling cooler and use the J-T cooler for the small amount of cooling required at the

W. J. Gully; D. Glaister; E. Marquardt

2004-01-01

342

Jahn-Teller effects in the near-infrared absorption spectrum of MgO:Fe2+  

Microsoft Academic Search

Near-infrared optical-absorption measurements on iron-doped MgO make possible a detailed study of the Jahn-Teller (JT) effect in the excited 5Eg state of Fe2+. From a moment analysis of the broad doubly peaked absorption band corresponding to the 5T2g--> 5Eg transition, and from the strength of the zero-phonon line (ZPL) at 1.5 K, we determine that the JT energy is EJT=1290

A. Hjortsberg; J. T. Vallin; F. S. Ham

1988-01-01

343

Applicability of the Joule-Thomson Cryocooler Coupled with Membrane-Based Purification System for Liquefaction of Natural Gas in Small Quantities  

Microsoft Academic Search

Joule-Thomson (J-T) cryocoolers using gas mixture have been studied theoretically and experimentally for a variety of applications. Gas separation technology using polymer membrane is emerging. In this paper the concept of coupling the J-T cooler with a hollow fiber membranes is presented. The apparatus can be used in many applications, like compressed natural gas (CNG) purification and condensation into LNG

A. Piotrowska; M. Chorowski

2008-01-01

344

An investigation into the mechanics of Joule-Thomson valve plug formation  

Microsoft Academic Search

Plug formation via contaminant condensation in sonic-flow Joule-Thomson (J-T) orifices was experimentally investigated. The cold end of the experimental apparatus consists of a precooler, a counterflow heat exchanger, and the J-T expander. Nitrogen gas is used as the refrigerant and water vapor is used as the contaminant. Results show that for the straight sonic orifices employed, plug formation occurred only

L. Wade; C. Donnelly; E. Joham; K. Johnson; R. Phillips

1988-01-01

345

Busy period analysis, rare events and transient behavior in fluid flow models  

Microsoft Academic Search

We consider a process {(Jt, Vt)}t >0 on Ex(0, o), such that {Jr} is a Markov process with finite state space-E, and {Vt} has a linear drift r on intervals where Jt- and reflection at 0. Such a process arises as a fluid flow model of current interest in telecommunications engineering for the purpose of modeling ATM technology. We compute

Søren Asmussen

1994-01-01

346

Development of a High Field Superconducting Magnet Cooled by a 2 K Cryocooler (2) - Characteristics of 2 K Cryocooler  

NASA Astrophysics Data System (ADS)

This paper describes the experimental results of a small 2 K Gifford-McMahon/Joule-Thomson type (GM/JT) cryocooler, which was used to cool a high-field superconducting magnet. We improved efficiency of the 2 K cryocooler by using a double Joule-Thomson (JT) valve. We also adopted a high capacity compressor to obtain over 1 W cooling capacity at 1.8 K. To reduce the cooling down time, we adopted a bypass line between the 1st stage heat exchanger and JT valve outlet. The 2 K-GM/JT cryocooler also has 4 K-operation mode, which is used for long time stand-by between 2 K-operation. Every switching between 4 K-mode and 2 K-mode needs many valve operations. To control cooling capacity of GM/JT cryocooler requires difficult manipulation of JT valves. To overcome this shortcoming, we developed an automatically controlling unit, which demonstrated easy operation.

Sato, A.; Nimori, S.; Maeda, M.; Nagai, H.; Matsumoto, F.; Takahashi, M.; Kuriyama, T.; Fujioka, T.; Ito, T.; Okamura, T.

2004-06-01

347

Properties of Gas Mixtures and Their Use in Mixed-Refrigerant Joule-Thomson Refrigerators  

NASA Astrophysics Data System (ADS)

The Joule-Thomson (J-T) effect has been widely used for achieving low temperatures. In the past few years, much progress has been made in better understanding the working mechanism of the refrigeration method and in developing prototypes for different applications. In this talk, there are three aspects of our research work to be discussed. First, some special thermal properties of the mixtures for achieving liquid nitrogen temperature range will be presented. Secondly, some important conclusions from the optimization of various mixed-refrigerant J-T cycles such as a simple J-T cycle and an auto-cascade mixed-refrigerant J-T cycle will be presented. Moreover, an auto-cascade, mixed-refrigerant J-T refrigerator with a special mixture capable of achieving about 50K will be mentioned. Finally, various prototypes based on the mixed-refrigerant refrigeration technology will be described. These applications include miniature J-T cryocoolers for cooling infrared detectors and high-temperature superconducting devices, cryosurgical knife for medical treatment, low-temperature refrigerators for biological storage and so forth. The on-going research work and unanswered questions for this technology will be also discussed.

Luo, E.; Gong, M.; Wu, J.; Zhou, Y.

2004-06-01

348

Experimental study of a mixed refrigerant Joule-Thomson cryocooler using a commercial air-conditioning scroll compressor  

NASA Astrophysics Data System (ADS)

Mixed refrigerant Joule-Thomson (MR J-T) cryocoolers have been used to create cryogenic temperatures and are simple, efficient, cheap, and durable. However, compressors for MR J-T cryocoolers still require optimization. As the MR J-T cryocooler uses a commercial scroll compressor developed for air-conditioning systems, compressor overheating due to the use of less optimized refrigerants may not be negligible, and could cause compressor malfunction due to burn-out of scroll tip seals. Therefore, in the present study, the authors propose procedures to optimize compressor operation to avoid the overheating issue when the MR J-T cryocooler is used with a commercial oil lubricated scroll compressor, and the present experimental results obtained for a MR J-T cryocooler. A single stage 1.49 kW (2 HP) scroll compressor designed for R22 utilizing a mixture of nitrogen and hydrocarbons was used in the present study. As was expected, compressor overheating and irreversible high temperatures at a compressor discharge port were found at the beginning of compressor operation, which is critical, and hence, the authors used a water injection cooling system for the compressor to alleviate temperature overshooting. In addition, a portion of refrigerant in the high-pressure stream was by-passed into the compressor suction port. This allowed an adequate compression ratio, prevented excessive temperature increases at the compressor discharge, and eventually enabled the MR J-T cryocooler to operate stably at 121 K. The study shows that commercial oil lubricated scroll compressors can be used for MR J-T cryocooling systems if care is exercised to avoid compressor overheating.

Lee, Jisung; Lee, Kyungsoo; Jeong, Sangkwon

2013-05-01

349

Direct superconducting pairing versus Jahn-Teller distortions; an analysis of a competition  

NASA Astrophysics Data System (ADS)

The competition between a direct, i.e. first-order, superconducting pairing interaction and Jahn-Teller (JT) distortions has been studied theoretically. Finite cluster simulations have been performed for systems which exhibit JT activity or which are pseudo JT active. The first-order pairing employed does not necessarily involve second-order elements such as the electron-phonon coupling or specific magnetic interactions. The pairing is defined only by parameters of the electronic Hamiltonian. In the first-order approach suggested the mixed quantum statistics of Cooper pairs is correctly taken into account. The quantum statistics of superconducting pairs combines fermionic on-site and bosonic intersite properties. Moves of Cooper pairs are not influenced by constraints caused by the Pauli antisymmetry principle (PAP) while the moves of unpaired fermions are. Driving force for the first-order pairing is the suppression of the PAP influence. Such a reduction of antisymmetry constraints is also feasible by JT distortions. It is demonstrated that JT activity and direct superconducting pairing compete in order to reduce the destabilizing influence of the PAP. Model calculations have been performed for a square-planar cluster of D 4h symmetry, a bicyclic network of D 2h symmetry and a tetrahedral T d cluster. JT distortions lower these point symmetries to D 2h, C 2h and D 2d. All calculations have been performed in the simple Hubbard approximation with a two-electron repulsion of the density-density on-site type and nearest-neighbour hoppings. We suggest that both JT distortions and the superconducting pairing can be explained without electron-phonon coupling. Both processes are electronically driven.

Böhm, Michael C.; Schulte, Joachim

2004-05-01

350

Pressure effects on Jahn-Teller distortion in perovskites: The roles of local and bulk compressibilities  

NASA Astrophysics Data System (ADS)

The interplay between the Jahn-Teller (JT) effect and octahedron tilting in transition-metal perovskites is investigated as a function of pressure. Our focus is on its effects on the exchange and electron-phonon interactions, both having a strong influence on materials properties. We demonstrate that the JT distortion in Cu2+ and Mn3+ is reduced upon compression and is eventually suppressed at pressures above 20 GPa. X-ray diffraction and x-ray absorption measurements in A2CuCl4 layer perovskites (A: Rb, CnH2n+1NH3; n=1-3) show that, although pressure slightly reduces the long Cu-Cl distance in comparison to the Cu-Cu distance in the layer, the JT distortion is stable in the 0-20 GPa range. The difference between lattice (?0C=0.14 GPa-1) and local CuCl6 (?0=0.016 GPa-1) compressibilities, together with the high stability of the JT distortion, lead to CuCl6 tilts upon compression. The evolution of the elongated CuCl6 octahedron in A2CuCl4, as well as MnF6 in CsMnF4 and MnO6 in LaMnO3 and DyMnO3, toward a nearly regular octahedron takes place above 20 GPa, in agreement with experimental results and a model analysis based on the JT energy derived from optical absorption spectroscopy: EJT=0.25-0.45 eV/Cu2+, EJT=0.45 eV/Mn3+ (CsMnF4), and EJT=0.25 eV/Mn3+ (LaMnO3). The proposed model clarifies controversial results about pressure-induced JT quenching in Cu2+ and Mn3+ systems, providing an efficient complementary means to predict pressure behavior in perovskites containing JT transition-metal ions.

Aguado, Fernando; Rodríguez, Fernando; Valiente, Rafael; Itiè, Jean-Paul; Hanfland, Michael

2012-03-01

351

Enhanced adsorption and desorption of VOCs vapor on novel micro-mesoporous polymeric adsorbents.  

PubMed

To enhance adsorption and desorption efficiency of volatile organic compounds from gas streams, we synthesized a series of well-developed micro-mesoporous hypercrosslinked polymeric adsorbents (MM-1, MM-2, and MM-3). The adsorption and desorption performance of dichloromethane and 2-butanone on newly synthesized adsorbents was investigated and compared with commercial micropore-dominated hypercrosslinked polymeric adsorbent (JT-001). The contributions of micropore and mesopore to adsorption and desorption of dichloromethane and 2-butanone on polymeric adsorbents were well elucidated. Consequently, the adsorbent MM-3 had been sorted out with high BET surface area (1606m(2)/g), large micropore and mesopore volumes (0.562mL/g and 1.046mL/g, respectively). The MM-3 exhibited the similar adsorption capacities with JT-001 for dichloromethane and 2-butanone at regions of p/p0<0.2, but had higher adsorption capacities than JT-001 at high relative pressures. The largest adsorption capacities of MM-3 for dichloromethane and 2-butanone at 308K were 1345.3mg/g and 853.5mg/g, respectively, which are about 1.78 and 1.88 times those of JT-001 under the same condition. Furthermore, the MM-3 exhibited higher desorption efficiencies than JT-001, especially for 2-butanone with a higher boiling point. PMID:24910052

Wang, Shuangshuang; Zhang, Liang; Long, Chao; Li, Aimin

2014-08-15

352

Pressure drop characteristics of cryogenic mixed refrigerant at macro and micro channel heat exchangers  

NASA Astrophysics Data System (ADS)

Mixed Refrigerant-Joule Thomson (MR-JT) refrigerators are widely used in various kinds of cryogenic systems these days. The temperature glide effect is one of the major features of using mixed refrigerants since a recuperative heat exchanger in a MR-JT refrigerator is utilized for mostly two-phase flow. Although a pressure drop estimation for a multi-phase and multi-component fluid in the cryogenic temperature range is necessarily required in MR-JT refrigerator heat exchanger designs, it has been rarely discussed so far. In this paper, macro heat exchangers and micro heat exchangers are compared in order to investigate the pressure drop characteristics in the experimental MR-JT refrigerator operation. The tube in tube heat exchanger (TTHE) is a well-known macro-channel heat exchanger in MR-JT refrigeration. Printed Circuit Heat Exchangers (PCHEs) have been developed as a compact heat exchanger with micro size channels. Several two-phase pressure drop correlations are examined to discuss the experimental pressure measurement results. The result of this paper shows that cryogenic mixed refrigerant pressure drop can be estimated with conventional two-phase pressure drop correlations if an appropriate flow pattern is identified.

Baek, Seungwhan; Jeong, Sangkwon; Hwang, Gyuwan

2012-12-01

353

Joule-Thompson cooler fabricated from microtubes of different diameters  

NASA Astrophysics Data System (ADS)

Joule-Thomson (JT) coolers have been widely used for cooling optoelectronic devices and for cryogenic applications. In the present investigation the performance and behaviors of a JT cooler fabricated from micro tubes of different diameters were studied. The cooler was comprised of circular tubes with diameters ranging from less than a hundred microns to a couple of millimeters. The smallest tube serves as a throttling device while the other tubes were used to fabricate a concentric-tube heat exchanger. Temperature drops were measured for nitrogen gas flowing through capillary tubes of different diameters and lengths. Gas dynamic theories were employed for analyzing the high- pressure gas flow in the JT cooler. Friction choking was observed under normal operating conditions, with strong compression and expansion waves appearing at the exit of the throttling tube. The simple design and configuration of the present JT cooler makes it suitable for batch fabrication using the photo lithography technique if the circular tubes are replaced by etched micron channels. This attractive feature of the micro-tube JT cooler can facilitate the integration of high-power optoelectronic devices and their cooling systems.

Chen, Kuan H.; Chen, Jing-Yu

1999-11-01

354

Helium liquefaction using cryorefrigerators  

NASA Astrophysics Data System (ADS)

A two-stage Gifford-McMahon refrigerator with a Joule-Thomson (J-T) stage connected in series, was extended to a small helium liquefier. The plant can operate automatically. Helium is liquefied within the J-T cycle, directly after the J-T valve, into a 3l tank. This liquid He is used for the indirect cooling of an externally accessible sample chamber, either by using helium contact gas, or by means of liquid He condensed from an external helium gas source. The second design is meant for laboratory applications. The liquid helium tank is not incorporated in the J-T cycle, but thermally connected to the J-T stage of the refrigerator. The He gas from an external source is then condensed into the 2l tank. The liquid helium is accessible via a top-loading sample tube. The refrigerating capacity of both devices is 2W at 4.5K. The cleaning procedures for the He gas to be condensed into the tanks, and the production of temperatures below 4.2K in the He bath are described.

Forth, Hans-Joachim

1986-12-01

355

Accurate calibration of the laser Raman system for the Karlsruhe Tritium Neutrino Experiment  

NASA Astrophysics Data System (ADS)

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to measure the neutrino mass via high-precision electron spectroscopy of the tritium ?-decay with a sensitivity of m? = 200 meV/c2 (90% C.L.). This can only be achieved if systematic uncertainties are minimized. An important parameter is the isotopic composition of the tritium gas used as the gaseous ?-electron source, which is measured inline by Raman spectroscopy. The KATRIN experiment requires a measurement trueness of better than 10% of said composition; to achieve this, accurate calibration of the Raman system for all hydrogen isotopologues (H2, HD, D2, HT, DT, T2) is required. Here we present two independent calibration methods, namely (i) a gas sampling technique, which promises high accuracy, but which is difficult to apply to tritiated species; and (ii) an approach via theoretical Raman signals (theoretical intensities plus spectral sensitivity), which in principle includes all six isotopologues. For the latter method we incorporated ab initio off-diagonal matrix elements of the polarizability from the literature; these have been verified by depolarization measurements. The system's spectral sensitivity was determined by a NIST-traceable SRM2242 luminescence standard. Both methods exhibited their individual merits and difficulties, but in cross calibration proved to be successful: a comparison for the non-radioactive isotopologues (H2, HD, D2) yielded agreement to better than 2% for the relative Raman response function. This is within the estimated (dominant) uncertainty of the theoretical Raman signal approach of about 3%. Therefore, one can be confident that, when using this approach, the trueness requirement of 10% for the KATRIN-relevant species (T2, DT, D2 and HT) will in all likelihood be exceeded.

Schlösser, Magnus; Rupp, Simone; Seitz, Hendrik; Fischer, Sebastian; Bornschein, Beate; James, Tim M.; Telle, Helmut H.

2013-07-01

356

Tritium neutrino mass experiments: measuring the molecular dissociation probability  

NASA Astrophysics Data System (ADS)

The next generation of tritium-based neutrino mass experiments (e.g. KATRIN, Project8) requires a comprehensive understanding of the distribution of molecular states excited in the decay. The distribution and the resulting dissociation probability have recently been calculated to high precision. Two dissociation experiments from the 1950s disagree with the modern predictions and further study is needed to resolve the discrepancy and validate the calculations. The Tritium Recoil-Ion Mass Spectrometer is designed to measure the molecular tritium branching ratio to the bound molecular ion ^3HeT^+ using a novel approach.

Bodine, Laura; Parno, Diana; Hamish Robertson, R. G.

2013-04-01

357

Review of Neutrino Mass Measurements  

SciTech Connect

After a brief summary of the recent achievements of neutrino physics, the concept of neutrino mass scale is clarified. The methods for the determination of the neutrino mass values are summarized and critically compared, in particular in the different and complementary contexts of cosmology, double and single beta decay. The attention is then focussed on the laboratory approaches to investigate neutrino mass. The role of neutrinoless double beta decay is explained and a short review of the present and most promising future experiments in this field is given. Single beta decay sensitivity is discussed, with brief descriptions of the KATRIN tritium experiment and of the recently proposed MARE rhenium project.

Giuliani, A. [Universita dell' Insubria, Via Valleggio 11, I-22100 Como (Italy); INFN-Milano, Via Valleggio 11, I-22100 Como (Italy)

2006-02-08

358

Precise energy of the 9.4 keV gamma transition observed in the 83Rb decay  

NASA Astrophysics Data System (ADS)

The energy of the 9.4 keV ?-transition observed in the 83Rb decay was established to be 9405.8(3) eV. This energy value was obtained from photon spectrometry measurements of the differences in the energies of closely spaced lines. The result allows one to determine more precisely the energy of conversion electrons of the 9.4 keV transition, which represent a unique tool for energy calibration of the tritium beta spectrum and systematic measurements in the KATRIN neutrino mass determination experiment.

Slezák, M.; Vénos, D.; Lebeda, O.; Trojek, T.

2012-02-01

359

Neutrino mass from beta decay  

NASA Astrophysics Data System (ADS)

The investigation of the endpoint spectrum of the tritium ? decay is still the most sensitive direct method to determine the neutrino mass scale. The KATRIN experiment currently being set up at the Forschungszentrum Karlsruhe will improve the neutrino mass sensitivity compared to the previous Mainz and Troitsk experiments by one order of magnitude down to 0.2 eV/c 2. The first generation of cryobolometric experiments at Genova and Milan using the isotope 187Re will be followed up by the MARE experiment which aims to eventually reach a similar sensitivity.

Weinheimer, Ch.

2007-06-01

360

Joule-Thomson cryogenic cooler with extremely high thermal stability  

NASA Technical Reports Server (NTRS)

An 80-K Joule-Thomson (J-T) cooling system designed for the Probe Infrared Laser Spectrometer (PIRLS) proposed for the Huygens Titan Probe of the Cassini Saturn orbiter mission is presented. The cryogenic cooling requirements of the PIRLS instrument are listed, and the cooler system design including details of a J-T cryostat, cold head, and dewar design is described along with the results of a thermal modeling effort and lab cooler performance testing. It is shown that by using active feedback temperature control of the cold head in combination with the self-regulating action of the J-T cryostat, a temperature stability of less than 0.1 mK/min is achieved by the cooler weighting 1.8 kg.

Bard, Steven; Wu, J. J.; Trimble, Curt

1991-01-01

361

Experimental investigation on mixed refrigerant Joule-Thomson cryocooler with flammable and non-flammable refrigerant mixtures  

NASA Astrophysics Data System (ADS)

The mixed refrigerant Joule-Thomson (MR J-T) cryocoolers have a wide application area covering the temperature range from 80 K to 200 K. The significant advantages of the system are simplicity of its design and working reliability with high level performance. The present paper discusses the experimental results of MR J-T cooler with different flammable and non-flammable mixture compositions. The work highlights the use of pressure-enthalpy and temperature-enthalpy diagrams for these mixtures to support the experimental results. A record lowest temperature of 65 K and a cooling capacity of 6 W at 80 K are obtained for a single stage MR J-T system starting at 300 K. Further, using a mixture of minimum flammable refrigerants, temperatures below 100 K is achieved.

Walimbe, N. S.; Narayankhedkar, K. G.; Atrey, M. D.

2010-10-01

362

Potential improvements in turbofan engine fuel economy  

NASA Technical Reports Server (NTRS)

The method developed for initial evaluation of possible performance improvements in the NASA Aircraft Energy Efficiency Program, directed toward improving the fuel economy of turbofan engines, is outlined, and results of the evaluation of 100 candidate engine modifications are presented. The study indicates that fuel consumption improvements of as much as 5% may be possible in current JT3D, JT8D, and JT9D turbofan engines. Aerodynamic, thermodynamic, material, and structural advances are expected to yield fuel consumption improvements on the order of 10 to 15% in advanced turbofan engines, with the greatest improvement stemming from significantly higher cycle pressure ratios. Higher turbine temperature and fan bypass ratios are also expected to contribute to fuel conservation.

Hines, R. W.; Gaffin, W. O.

1976-01-01

363

Internal Transport Barrier Control Using Counter Electron Cyclotron Current Drive  

NASA Astrophysics Data System (ADS)

Shear Reversal Discharges are common experimental scenarios in many Tokamaks to obtain high performance plasmas with Internal Transport Barriers (ITB). Quasi-steady state operation with record fusion performance has been obtained at JT-60U with q_min approaching 2. However, shear reversal discharges without ITB control are self-destructive due to an intrinsic positive feedback mechanism that links the reduction of transport at the ITB with safety profiles. At JT60-U, disruptions occurring when q_min ~ 2 have prevented the extension of the high performance beyond the transient phase. An ITB control mechanism with counter Electron Cyclotron Current Drive is proposed as a method to break the ITB intrinsic positive feedback and extend the high performance phase of shear reversal tokamak plasma configurations. The feasibility of this control scheme is demonstrated with simulations generated with a power balance transport code benchmarked with shear reversal experimental data from JT-60U.

Romero, J. A.; Yoshino, R.

1999-11-01

364

Preliminary experimental and numerical study of transient characteristics for a Joule-Thomson cryocooler  

NASA Astrophysics Data System (ADS)

To establish a tool for computer-aided design, a preliminary experimental and numerical study of transient characteristics for a Joule-Thomson (J-T) cryocooler is developed in the present work. A simplified transient one-dimensional model of momentum and energy transport is used to simulate the flow and heat transfer characteristics. The computational results for cool-down time agree with the experimental data. The transient temperature variations of high pressure gas, tube wall, low pressure gas, glass Dewar and mandrel at the grid point near the valve exit are shown. From the spatial temperature distributions of high and low pressure gases along the finned tube at the moment of cool-down, it is proposed that the J-T cooler currently used may be reduced in terms of both size and weight; factors which are very important in a miniature J-T cryocooler.

Chou, F.-C.; Pai, C.-F.; Chien, S. B.; Chen, J. S.

365

Lightly doped dimerized spin chain in the one-dimensional t-J-J' model  

NASA Astrophysics Data System (ADS)

We study the one-dimensional t-J-J'-model in the limit of small hole doping x and small J/t, J'/t. Special emphasis is put on the regime J'/J?0.5, where a spin gap is present at small doping and the undoped spin chain is strongly dimerized. Using a perturbative approach and Luttinger liquid arguments, we demonstrate for this nonintegrable class of models that the charge degrees of freedom behave as noninteracting spinless solitons in the dilute hole limit. Our approach is also used to evaluate the energy and mass renormalization of a single hole. Interestingly, the corrections of these quantities are in powers of ?(J/t). At J'/J=0.5 we construct a variational spin-polaron wave function for the hole and find good agreement with our perturbative results.

Seidel, Alexander; Lee, Patrick A.

2004-03-01

366

Effect of dynamics on the elastic softening of vacancies in Si  

NASA Astrophysics Data System (ADS)

Recently, elastic softening at temperatures below 20 K has been observed in nondoped floating zone silicon. From the experimental analysis, it has been suggested that this softening is caused by an intrinsic vacancy defect through the Jahn-Teller (JT) effect. We have theoretically studied the relations between softening and the vacancies. The ground state of the JT distortion is stiff. However, by considering atomistic dynamical and anharmonic effects, it is found that low-energy excitations exist in the E-mode distortion and that different polarizations of the E-distortion can be easily interchanged. The calculated energy barriers for the reorientation of JT distortions are consistent with other experiments and calculations. This low-lying mode can be the cause of softening in the elastic responses.

Shirai, Koun; Ishisada, Jun

2014-02-01

367

Orbital correlations in the pseudo-cubic O and rhombohedral R-phases of LaMnO{sub 3}.  

SciTech Connect

The local and intermediate structure of stoichiometric LaMnO{sub 3} has been studied in the pseudocubic and rhombohedral phases at high temperatures (300-1150 K). Neutron powder diffraction data were collected and a combined Rietveld and high real space resolution atomic pair distribution function analysis was carried out. The nature of the Jahn-Teller (JT) transition around 750 K is confirmed to be orbital order to disorder. In the high-temperature orthorhombic (O) and rhombohedral (R) phases, the MnO{sub 6} octahedra are still fully distorted locally. More importantly, the intermediate structure suggests the presence of local ordered clusters of diameter {approx} 16{angstrom} ({approx} 4 MnO{sub 6} octahedra) implying strong nearest-neighbor JT antiferrodistortive coupling. These clusters persist well above the JT transition temperature even into the high-temperature R phase.

Qiu, X.; Proffen, Th.; Mitchell, J. F.; Billinge, S. J. L.; Michigan State Univ.; LANL

2005-01-01

368

Effective approach to the Nagaoka regime of the two-dimensional t-J model  

NASA Astrophysics Data System (ADS)

We argue that the t-J model and the recently proposed Ising version of this model give the same physical picture of the Nagaoka regime for J/t?1. In particular, both models are shown to give compatible results for a single Nagaoka polaron as well as for a Nagaoka bipolaron. When compared to the standard t-J or t-Jz models, the Ising version allows for a numerical analysis on much larger clusters by means of classical Monte Carlo simulations. Taking advantage of this fact, we study the low doping regime of the t-J model for J/t?1 and show that the ground state exhibits phase separation into hole-rich ferromagnetic and hole-depleted antiferromagnetic regions. This picture holds true up to a threshold concentration of holes ???t?0.44J/t. Analytical calculations show that ?t=J/2?t.

Ma?ka, M. M.; Mierzejewski, M.; Kochetov, E. A.; Vidmar, L.; Bon?a, J.; Sushkov, O. P.

2012-06-01

369

Performance Investigations of a 4 to 10 K Long-Life Mechanical Cryocooler  

NASA Astrophysics Data System (ADS)

We believe that the quickest way of obtaining a reliable space cooler in the range of 4 to 10 K is to combine a Stirling mechanical cooler with a Joule-Thomson (J-T) cooler. In this approach we perform the bulk of the cooling with the Stirling cooler and use the J-T cooler for the small amount of cooling required at the lowest temperatures. The recuperative J-T stage can reach low temperatures more easily because it does not have the regenerator limitations shared by Stirling and Pulse Tube mechanical coolers. We present our system concept in detail and discuss its merits. To demonstrate the capabilities of a hybrid cooler, we built a breadboard version consisting of a precooler, a J-T circulating compressor, and a cold head. With it we achieved closed-cycle refrigeration rates of 35 mW at 6 K and 10 mW at 3.7 K. For simplicity we used a commercial Gifford McMahon (GM) refrigerator as our precooler and focused on building the J-T compressor and passive cold head. The J-T compressor was an Oxford-style linear compressor equipped with an external reed valve package. The cold head consisted of heat exchangers, heat sinks, and an expansion valve. The system worked quite well. The performance was transparent and the results agreed with our analytical models. We are proceeding with the construction of a full engineering model on a NASA technology development program, the Advanced Cryocooler Development Program (ACTDP). Within 2 years we will have a complete engineering model of the mechanical cryocooler capable of 4 K operation.

Gully, W. J.; Glaister, D.; Marquardt, E.

2004-06-01

370

The phase diagram of the two-dimensional t-J model from high temperature expansions  

SciTech Connect

This paper reports on the phase diagram of the 2D t-J model which has been investigated using high temperature expansions. Series for the Helmholtz free energy, the inverse compressibility, the chemical potential and the uniform spin susceptibility through tenth order on a square lattice have been calculated using the finite cluster method. The series are analytically continued beyond their radius of convergence by Pade and integral approximants. The most accurate extrapolations can be made for the Helmholtz free energy where for J/t {approx} 0.3 and n {approx} 0.9 we can reach T {approximately} t/5. The authors can test the accuracy of the continuation methods by comparing with the 1D results for the boundary of phase separation. In 2D a region of phase separation was found at T = 0 for J/t lying above a line extending from J/t = 3.8 at zero filling to J/t = 1.2 at half filling. No phase separation was found at very small J/t contrary to an earlier suggestion which was based on results from exact diagonalization on 4 {times} 4 clusters but in agreement with Quantum Monte Carlo (QMC) calculations on the Hubbard model. For very small J/t near half filling where the Nagaoka effect is possible, the authors find a region of divergent uniform magnetic susceptibility at T = 0. However the divergence is very weak when compared with the exponential behavior expected from a 2D ferromagnet. This might imply a substantially reduced moment which is consistent with the recent QMC estimates.

Putikka, W.O.; Luchini, M.U.; Rice, T.M. (Theoretische Physik, Eidgenossische Technische Hochschule Honggerbreg, CH-8093 Zurich (CH))

1992-03-01

371

First principles study of Jahn–Teller effects in Li x MnPO 4  

Microsoft Academic Search

The crystal structure and electronic properties of LixMnPO4 (x=0, 0.5, 1) as cathode material of rechargeable lithium ion batteries, are studied through first principles calculations. Results show that the large volume change from LiMnPO4 to MnPO4 is mainly the result of Jahn–Teller (JT) distortion around Mn3+ ions in MnPO4. The JT effect also plays an important role in Li0.5MnPO4 compound.

Z. X. Nie; C. Y. Ouyang; J. Z. Chen; Z. Y. Zhong; Y. L. Du; D. S. Liu; S. Q. Shi; M. S. Lei

2010-01-01

372

Nacelle Aerodynamic and Inertial Loads (NAIL) project. Appendix B  

NASA Technical Reports Server (NTRS)

The testing was conducted on the Boeing-owned 747 RA001 test bed airplane during the concurrent 767/JT9D-7R4 engine development program. Following a functional check flight conducted from Boeing Field International (BFI) on 3 October 1980, the airplane and test personnel were ferried to Valley Industrial Park (GSG) near Glasgow, Montana, on 7 October 1980. The combined NAL and 7670JT9D-7R4 test flights were conducted at the Glasgow remote test site, and the airplane was returned to Seattle on 26 October 1980.

1981-01-01

373

The effect of external magnetic field on the Raman peaks in manganites  

NASA Astrophysics Data System (ADS)

We report here a microscopic theoretical model study exhibiting the effect of external magnetic field on the Raman excitation peaks in the CMR manganite system. The Hamiltonian consists of Jahn-Teller (J-T) distortion in eg band, the double exchange interaction and the Heisenberg spin-spin interaction. Further the phonons are coupled to eg band electrons, J-T distorted eg band and the double exchange interaction. The Raman spectral intensity is calculated from the imaginary part of the phonon Green function. The spectra exhibits three peaks besides a very weak high energy peak. The magnetic field effect on these peaks are reported.

Sahu, A. K.; Rout, G. C.

2014-04-01

374

Spring-Loaded Joule-Thomson Valve  

NASA Technical Reports Server (NTRS)

Improved design reduces clogging and maintains constant pressure drop as flow rate varies. Spring-Loaded Joule-Thomson Valve pressure drop regulated by spring pushing stainless-steel ball against soft brass seat. Pressure drop remains nearly constant, regardless of helium flow rate and of any gas contaminants frozen on valve seat. Because springloaded J-T valve maintains constant pressure drop, upstream roomtemperature throttle valve adjusts flow rate precisely for any given upstream pressure. In addition, new valve relatively invulnerable to frozen gas contaminants, which clog fixed-orifice J-T valves.

Jones, J. A.; Britcliffe, M. J.

1986-01-01

375

Analysis of turbofan engine performance deterioration and proposed follow-on tests  

NASA Technical Reports Server (NTRS)

Data and engine parts on in-service JT3D and JT8D engines were analyzed and documented relative to engine deterioration. It is concluded that the fan-compressor system of these engines contributes to the long term engine deterioration. An engine test and instrumentation plan was formulated for a proposed follow-on program. The goal of this program is to verify the above conclusion and to attempt to identify more precisely which components of the fan-compressor system are at fault.

Sallee, G. P.; Kruckenberg, H. D.; Toomey, E. H.

1975-01-01

376

Improved components for engine fuel savings  

NASA Technical Reports Server (NTRS)

NASA programs for developing fuel saving technology include the Engine Component Improvement Project for short term improvements in existing air engines. The Performance Improvement section is to define component technologies for improving fuel efficiency for CF6, JT9D and JT8D turbofan engines. Sixteen concepts were developed and nine were tested while four are already in use by airlines. If all sixteen concepts are successfully introduced the gain will be fuel savings of more than 6 billion gallons over the lifetime of the engines. The improvements include modifications in fans, mounts, exhaust nozzles, turbine clearance and turbine blades.

Antl, R. J.; Mcaulay, J. E.

1980-01-01

377

Test-engine and inlet performance of an aircraft used for investigating flight effects on fan noise  

NASA Astrophysics Data System (ADS)

As part of the NASA Flight Effects on Fan Noise Program, a Grumman OV-1B Mohawk aircraft was modified to carry a modified and instrumented Pratt & Whitney JT15D-1 turbofan engine. Onboard flight data, together with simultaneously measured farfield acoustic data, comprise a flight data base to which JT15D-1 static and wind-tunnel data are compared. The overall objective is to improve the ability to use ground-based facilities for the prediction of flight inlet radiated noise. This report describes the hardware and presents performance results for the research engine.

Golub, R. A.; Preisser, J. S.

1984-04-01

378

Test-engine and inlet performance of an aircraft used for investigating flight effects on fan noise  

NASA Technical Reports Server (NTRS)

As part of the NASA Flight Effects on Fan Noise Program, a Grumman OV-1B Mohawk aircraft was modified to carry a modified and instrumented Pratt & Whitney JT15D-1 turbofan engine. Onboard flight data, together with simultaneously measured farfield acoustic data, comprise a flight data base to which JT15D-1 static and wind-tunnel data are compared. The overall objective is to improve the ability to use ground-based facilities for the prediction of flight inlet radiated noise. This report describes the hardware and presents performance results for the research engine.

Golub, R. A.; Preisser, J. S.

1984-01-01

379

Local structure of La1-xSrxCoO3 determined from EXAFS and neutron PDF studies  

SciTech Connect

The combined local structure techniques, extended X-ray absorption fine struture (EXAFS) and neutron pair distribution function (PDF) analysis, have been used for temperatures 4 {<=} T {<=} 330 K to rule out a large Jahn-Teller (J-T) distortion of the Co-O bond in La{sub 1-x}Sr{sub x}CoO{sub 3} for a significant fraction of Co sites (x {<=} 0.35), indicating few, if any, J-T active, single-occupied e{sub g} Co sites exist.

Proffen, Thomas [Los Alamos National Laboratory; Sundaram, Nalini [UCSC; Jiang, Y [UCSC; Anderson, Ingrid [UCSC; Belanger, D P [UCSC; Booth, C H [LBNL; Bridges, F [UCSC; Mitchell, J F [ANL; Zheng, H [ANL

2008-01-01

380

Advances in small Joule-Thomson coolers  

NASA Astrophysics Data System (ADS)

Considerable work has been done on the development of a new type of heat exchanger for Joule Thomson, JT, coolers which is referred to as a matrix-tube heat exchanger. This has permitted coolers to be built that are smaller than conventional finned tube heat exchangers and has made it easier to build multistage and multicircuit heat exchangers. This paper discusses some characteristics of JT cooling and describes a number of different types of heat exchangers along with typical applications. Specific information is given on the size and cooling characteristic of matrix-tube-type heat exchangers.

Longsworth, Ralph C.

381

MATE program: Erosion resistant compressor airfoil coating, volume 2  

NASA Technical Reports Server (NTRS)

The performance of candidate erosion resistant airfoil coatings installed in ground tested experimental JT8D and JT9D engines and subjected to cyclic endurance at idle, takeoff and intermediate power conditions has been evaluated. Engine tests were terminated prior to the scheduled 1000 cycles of endurance test due to high cycle fatigue fracture of the Gator-Gard plasma sprayed 88WC-12Co coating on titanium alloy airfoils. Coated steel (AMS5616) and nickel base alloy (Incoloy 901) performed well in both engine tests. Post test airfoil analyses consisted of binocular, scanning electron microscope and metallographic examinations.

Freling, Melvin

1987-01-01

382

Structure--properties relationships for manganese perovskites  

SciTech Connect

By combining the results of dc magnetization, ac susceptibility, magnetoresistivity, magnetostriction, and x-ray and neutron powder diffraction data for stoichiometric La{sub 1{minus}x}Sr{sub x}MnO{sub 3} the authors have constructed a phase diagram that describes the magnetic, transport, and structural properties and the relationships among them as a function of composition and temperature. Correlations among physical and structural properties have been observed that are consistent with a competition between ferromagnetism and JT distortion. A metallic state occurs below the Curie temperature when both coherent and incoherent JT distortions are suppressed.

Dabrowski, B.; Xiong, X.; Chmaissem, O.; Bukowski, Z.; Jorgensen, J. D.

1999-10-14

383

Erratum: ``Diffusive Migration of Low-Mass Protoplanets in Turbulent Disks'' (ApJ, 647, 1413 [2006])  

NASA Astrophysics Data System (ADS)

Because of an error in implementing proof corrections, fractional terms for the gamma functions in equation (1) and the unnumbered display equation following equation (4) are set incorrectly in the published version of the paper. These equations should read:D(J)=1/2-????(t-?/2,J)??(t+?/2,J)d? (1)and(?J)2=[?(J)?t+0?t??(t')dt'2=?(J)2(?t)2+0?tdtm-2tm2tmd???(tm-?/2,J)??(tm+?/2,J). The Press sincerely regrets these errors.

Johnson, Eric T.; Goodman, Jeremy; Menou, Kristen

2007-01-01

384

Vacuum insulation of the high energy negative ion source for fusion application  

NASA Astrophysics Data System (ADS)

Vacuum insulation on a large size negative ion accelerator with multiple extraction apertures and acceleration grids for fusion application was experimentally examined and designed. In the experiment, vacuum insulation characteristics were investigated in the JT-60 negative ion source with >1000 apertures on the grid with the surface area of ~2 m2. The sustainable voltages varied with a square root of the gap lengths between the grids, and decreased with number of the apertures and with the surface area of the grids. Based on the obtained results, the JT-60SA (super advanced) negative ion source is designed to produce 22 A, 500 keV D- ion beams for 100 s.

Kojima, A.; Hanada, M.; Hilmi, A.; Inoue, T.; Watanabe, K.; Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Tobari, H.; Kobayashi, S.; Yamano, Y.; Grisham, L. R.

2012-02-01

385

Anisotropy and the inversion splitting in the ? Jahn - Teller system  

Microsoft Academic Search

We present an analysis of the Jahn - Teller (JT) system in which both possible h-type quadratic terms are considered. It is well known that this results in pentagonal or trigonal minima on the potential energy surface, depending on the magnitudes of the coupling constants. Although the positions of the minima with quadratic couplings are known, the anisotropic effects which

Y. M. Liu; J. L. Dunn; C. A. Bates; V. Z. Polinger

1997-01-01

386

Tunneling Path and Ground State Crossover in Linear T?( e? t 2) and Quadratic G?( g? h) Jahn–Teller Systems  

Microsoft Academic Search

It was believed that vibronic coupling does not alter the symmetry and degeneracy of the ground state of a Jahn–Teller (JT) system. However this conjecture was found to be untrue in the case of the icosahedral H?h system, where in strong coupling the system has a ground vibronic state of A symmetry instead of the expected H symmetry. A physical

Huanming Li; Victor Z. Polinger; Janette L. Dunn; Colin A. Bates

2003-01-01

387

An Innovative Post-Secondary Consumer-Family Life Skills Program  

ERIC Educational Resources Information Center

Describes a Georgia state project which developed ten 15-minute television programs with teachers guides, thirty slide-tape presentations, and twenty learning modules for use in teaching consumer and family life skills to students in area vocational technical schools and to adults in local communities. (JT)

Boyd, Fannie Lee; Willett, Ann R.

1977-01-01

388

Consumer Perceptions of Health Care Services: Implications for Academic Medicine  

ERIC Educational Resources Information Center

Factor analytic development of various measures of consumer perceptions regarding characteristics of doctors and health care services is described. Findings are discussed in relation to program planning and evaluation in medical education, and suggestions for future research are noted. (Editor/JT)

Ware, John E., Jr.; And Others

1975-01-01

389

Smart Weapons Operability Enhancement Joint Test and Evaluation Program Grayling 1: preliminary results  

Microsoft Academic Search

The primary objective of the Smart Weapons Operability Enhancement (SWOE) Joint Test and Evaluation (JT&E) Program is to validate the SWOE Process for the Office of the Secretary of Defense. The SWOE Process is a physics based scene generation capability that will enhance the performance of future smart weapon systems for a global variety of battlefield environments. This process is

James P. Welsh; George G. Koenig

1993-01-01

390

Primary Care, Ambulatory Care, and Family Medicine: Overlapping But Not Synonymous  

ERIC Educational Resources Information Center

Defines and depicts graphically the relationships between primary, secondary, and tertiary care functions (from least to most intensified phases of medical care); ambulatory care (care of sick or well people not confined to bed); and family medicine (an emerging medical discipline focusing on complete and longterm care of the family). (JT)

Reynolds, Robert E.

1975-01-01

391

Effectiveness of an International Health Elective As Measured by NBME Part II  

ERIC Educational Resources Information Center

National Board of Medical Examiner's exam results show that U.S. medical students who participated between 1968 and 1974 in Yugoslav or Israeli international fellowship programs sponsored by the Association of American Medical Schools and the U.S. Public Health Service gained knowledge of preventive medicine and public health. (JT)

Waddell, Wendy; And Others

1976-01-01

392

Cancelled Student Loans: For the Benefit of the Grantor?  

ERIC Educational Resources Information Center

The statuory and regulatory framework regarding treatment of scholarships and fellowships under the Internal Revenue Code and the interpretations and limitations upon these requirements that the courts have developed are examined with the conclusion that there is need for litigation and possibly Congressional ammendment to the statutes. (JT)

Boe, Caroleen C.

1974-01-01

393

Bookstore in Trouble: The Proverbial Iceberg  

ERIC Educational Resources Information Center

Examines the plight of two troubled bookstores, both state system stores with state charters as nonprofit corporations, probing some of their weaknesses, failures, and resultant difficulties and the positive action, including structural change and new management, involved in recovery and restoration of adequate operating funds. (JT)

Sanderson, Ivan L.

1975-01-01

394

Comparison of a Private Family Practice and a University Teaching Practice  

ERIC Educational Resources Information Center

When a private family practice in Hamilton, Canada, became a teaching practice of McMaster University, a before-and-after study was conducted to compare characteristics of the patients and the impact of the change on the practice. Conclusion: Such a transplanted private practice is a realistic teaching resource in primary care. (Editor/JT)

Rudnick, K. Vincent; And Others

1976-01-01

395

Jumping translocations of 1q12 in multiple myeloma: a novel mechanism for deletion of 17p in cytogenetically defined high-risk disease.  

PubMed

Multiple myeloma (MM) is a B-cell malignancy driven in part by increasing copy number alterations (CNAs) during disease progression. Prognostically significant CNAs accumulate during clonal evolution and include gains of 1q21 and deletions of 17p, among others. Unfortunately, the mechanisms underlying the accumulation of CNAs and resulting subclonal heterogeneity in high-risk MM are poorly understood. To investigate the impact of jumping translocations of 1q12 (JT1q12) on receptor chromosomes (RCs) and subsequent clonal evolution, we analyzed specimens from 86 patients selected for unbalanced 1q12 aberrations by G-banding. Utilizing spectral karyotyping and locus-specific fluorescence in situ hybridization, we identified 10 patients with unexpected focal amplifications of an RC that subsequently translocated as part of a sequential JT1q12 to one or more additional RCs. Four patients exhibited amplification and translocation of 8q24 (MYC), 3 showed amplification of 16q11, and 1 each displayed amplification of 18q21.3 (BCL2), 18q23, or 4p16 (FGFR3). Unexpectedly, in 6 of 14 patients with the combination of the t(4;14) and deletion of 17p, we identified the loss of 17p as resulting from a JT1q12. Here, we provide evidence that the JT1q12 is a mechanism for the simultaneous gain of 1q21 and deletion of 17p in cytogenetically defined high-risk disease. PMID:24497533

Sawyer, Jeffrey R; Tian, Erming; Heuck, Christoph J; Epstein, Joshua; Johann, Donald J; Swanson, Charles M; Lukacs, Janet L; Johnson, Marian; Binz, Regina; Boast, Angela; Sammartino, Gael; Usmani, Saad; Zangari, Maurizio; Waheed, Sarah; van Rhee, Frits; Barlogie, Bart

2014-04-17

396

The Perfect Politician  

ERIC Educational Resources Information Center

The perfect politician, the ideal political ally to a library, is often but not always an elected official. He or she is always an effective champion of "reasonable financial support," i.e., "the amount...which a thoroughly competent librarian can spend wisely." That is what J.T. Wyer, director of the New York State Library, said in his "What the…

Berry, John N., III

2010-01-01

397

Alexander v. Gardner-Denver: A Threat to Title VII Rights  

ERIC Educational Resources Information Center

An examination of the decision on the rights of an employee, who has unsuccessfully pursued a race or sex discrimination claim through arbitration, to "relitigate" the claim under Title VII, Civil Rights Act of 1964. Conclusion: the decision endangers Title VII rights by granting too much weight to prior arbitration awards. (JT)

Richards, Richard F.

1975-01-01

398

The Role of Government in EFT. Part II. Testimony Presented to the National Commission on Electronic Fund Transfers, November 12, 1976.  

National Technical Information Service (NTIS)

The witnesses who testified at this public hearing on EFT (Electronic Funds Transfer) are: D.I. Baker, U.S. Department of Justice; J.J. Reynolds, Interbank Card Association; R. Capone, J.C. Penney Co.; J.T. Ellington, Jr., U.S. Postal Service; T.H. Huston...

1977-01-01

399

Time Management in Higher Education Administration: A Case Study  

ERIC Educational Resources Information Center

Drawing on data from a staff development project for administrators in a college at a major American university, it was determined that there is considerable commonality across individuals and that it is possible to deal with such issues as time management, job stress, and enjoyment on an organizational level. (Editor/JT)

Lewis, Darrell R.; Dahl, Tor

1976-01-01

400

Tort Law: Psychotherapist-Patient Privilege--Patient's Dangerous Condition--Confidentiality--Legal Duty to Warn Potential Victim  

ERIC Educational Resources Information Center

After telling a psychologist his intentions to kill Tatiana Tarasoff, Prosenjit Poddar did so. In Tarasoff v. Regents of University of California the psychologist was found liable for not warning the victim of danger. The author contends that the decision, in terms of medical capabilities, may be ahead of its time. (JT)

Burns, Robert E.

1975-01-01

401

Joule-Thomson cryocooler for space applications  

Microsoft Academic Search

A J-T cryocooler is being developed for space applications. It is under laboratory testing and will be flight-tested aboard the Space Shuttle in middle to late 1997. A seal-ability study confirmed that the EDM design is robust and can accommodate a wide range of heat loads while maintaining the development heritage.

R. Levenduski; R. Scarlotti

1996-01-01

402

Properties of Gas Mixtures and Their Use in Mixed-Refrigerant Joule-Thomson Refrigerators  

Microsoft Academic Search

The Joule-Thomson (J-T) effect has been widely used for achieving low temperatures. In the past few years, much progress has been made in better understanding the working mechanism of the refrigeration method and in developing prototypes for different applications. In this talk, there are three aspects of our research work to be discussed. First, some special thermal properties of the

E. Luo; M. Gong; J. Wu; Y. Zhou

2004-01-01

403

A mixed-gas miniature Joule-Thomson cooling system  

NASA Astrophysics Data System (ADS)

A mixed-gas Joule-Thomson (JT) cooling system is investigated in which a micromachined JT cold stage of 60 × 10 × 0.7 mm3 is combined with a linear compressor. The cooling system is operated between 1.3 bar and 9.4 bar with a ternary gas mixture of 39 mol% methane, 20 mol% ethane and 41 mol% isobutane. It cools down to below 130 K, and at a cold-tip temperature of 150 K, a cooling power of 46 mW is obtained at a mass-flow rate of 1.35 mg s-1. The background losses are experimentally determined to be 20 mW and are in good agreement with the calculated value of 21 mW. The linear compressor can be used to drive 19 of these miniature JT cold stages in parallel, e.g. for cooling optical detectors in future space missions. In this mode, the compressor pressure ratio is slightly less, resulting in a net cooling power of 23 mW per miniature JT cold stage.

Derking, J. H.; Vermeer, C. H.; Tirolien, T.; Crook, M. R.; ter Brake, H. J. M.

2013-10-01

404

Student Pre- and Post-Evaluation of an Off-Campus Clinical Clerkship  

ERIC Educational Resources Information Center

Describes the development and use of standardized forms found to be effective for evaluating clinical clerkship experiences of pharmacy students. Copies of the Preliminary Questionnaire and the Post-Evaluation Form are included along with the goals of the Washington State University College of Pharmacy Clinical Pharmacy Program. (JT)

Campbell, R. Keith

1975-01-01

405

MPI Enhancements in John the Ripper  

NASA Astrophysics Data System (ADS)

John the Ripper (JtR) is an open source software package commonly used by system administrators to enforce password policy. JtR is designed to attack (i.e., crack) passwords encrypted in a wide variety of commonly used formats. While parallel implementations of JtR exist, there are several limitations to them. This research reports on two distinct algorithms that enhance this password cracking tool using the Message Passing Interface. The first algorithm is a novel approach that uses numerous processors to crack one password by using an innovative approach to workload distribution. In this algorithm the candidate password is distributed to all participating processors and the word list is divided based on probability so that each processor has the same likelihood of cracking the password while eliminating overlapping operations. The second algorithm developed in this research involves dividing the passwords within a password file equally amongst available processors while ensuring load-balanced and fault-tolerant behavior. This paper describes John the Ripper, the design of these two algorithms and preliminary results. Given the same amount of time, the original JtR can crack 29 passwords, whereas our algorithms 1 and 2 can crack an additional 35 and 45 passwords respectively.

Sykes, Edward R.; Lin, Michael; Skoczen, Wesley

2010-11-01

406

Is The Modern Lease a Contract or a Conveyance?--A Historical Inquiry  

ERIC Educational Resources Information Center

Argues that "contrary to conventional wisdom, current landlord-tenant law is modern, commercial, and already grounded in contract doctrine." Discusses the origins of the doctrines most frequently cited as illustrations of leasings property basis and redevelops the role of property law in adjudicating leasing disputes. (JT)

Siegel, Stephen A.

1975-01-01

407

A Preliminary Examination of the In-Training Evaluation Report  

ERIC Educational Resources Information Center

The In-Training Evaluation Report (ITER), in use by the Royal College of Physicians and Surgeons of Canada for examining the competencies of candidates eligible for the certifying examination, was tested for validity and reliability. This analysis suggests revisions but declares the ITEA a useful instrument to aid in candidate assessment. (JT)

Skakun, Ernest N.; And Others

1975-01-01

408

Compensation of beamlet repulsion in a large negative ion source with a multi aperture accelerator  

SciTech Connect

Excess heat loads to accelerator grids limit extension of pulse length in operation of the large negative ion sources with multi aperture accelerator. Part of the heat loads is caused by interception of deflected beamlets due to their space charge repulsion. In this paper, a beamlet steering technique using aperture offset was examined for compensation of the beamlet deflections utilizing a three dimensional beam analysis simulating the D{sup -} negative ion source of JT-60 U. The beamlet deflection was analyzed in detail using fifty beamlets, which were extracted from apertures arranged in a lattice pattern of 10x5. The simulation showed successful compensation of the beamlet deflection by aperture offsets defined according to the thin lens theory. Even if the beam energy was changed, the necessary aperture offset would not be changed maintaining the perveance and a ratio of extraction and acceleration voltage. In JT-60 U, it was shown that the aperture offset of less than 1.0 mm would be enough to compensate the repulsion of all beamlets. When the magnetic field was applied for suppression of co-extracted electrons, necessary aperture offset was estimated to be {+-}0.5 mm for 500 keV D{sup -} ion beam in JT-60 U, in addition to the offset for the space charge repulsion. This result showed good agreements with the previous experimental results and design study of the JT-60 U N-NBI.

Kashiwagi, M.; Inoue, T.; Hanada, M.; Kamada, M.; Taniguchi, M.; Umeda, N.; Watanabe, K. [Japan Atomic Energy Agency, 801-1, Nukoyama, Naka, 311-0193 (Japan); Grisham, L. R. [Princeton University, Plasma Physics Laboratory, Princeton (United States)

2009-03-12

409

The Yale Tuition Postponement Plan in the Mid-Seventies  

ERIC Educational Resources Information Center

The Yale Tuition Postponement Plan (TPO), an income-contingent loan scheme, is discussed and analysed with reference to the interest rate crisis and default rates. Conclusion: the high default rate is the most dangerous weakness of contingency loans, and this Plan is the only scheme of its kind likely to exist in the near future. (Editor/JT)

West, E. G.

1976-01-01

410

Habits, Fears, and Desires of the Genus Graduate Student  

ERIC Educational Resources Information Center

Based on interviews with graduate students in English, biochemistry, and psychology the author discusses common characteristics of graduate students (lifelong observers with faith in authority and strong emotional attachment to a minute field of inquiry) and notes implications for their teaching and their contributions to society. (JT)

Taylor, Anne Robinson

1976-01-01

411

Student Attrition in North American Veterinary Schools  

ERIC Educational Resources Information Center

Data presented shows a progressive reduction in North American veterinary student attrition from 12.8 percent in 1966 to 3.1 percent in 1974. The prediction is that with improved selection procedures and time-variable instructional programs the rate will drop and stabilize at approximately two percent. (JT)

Hooper, Billy E.; Brown, Roger E.

1975-01-01

412

HOW TO SELECT THE PROPER SECURITY AND EQUIPMENT SURVEILLANCE SYSTEMS TO PROTECT YOUR FACILITIES.  

ERIC Educational Resources Information Center

IN PRESENTING A SURVEY OF MODERN SECURITY SYSTEMS, THIS BOOKLET DISCUSSES THE REQUIREMENTS FOR SURVEILLANCE AND PROTECTION OF AREAS, PERIMETER, AND OBJECTS. A VARIETY OF EQUIPMENT IS DESCRIBED WITH DISCUSSION OF OPERATING PROCEDURES, COSTS, AND RECENT DEVELOPMENTS IN SECURITY SYSTEMS. (JT)

Honeywell, Inc., Minneapolis, Minn.

413

Operational Management of Area Environment.  

ERIC Educational Resources Information Center

Three phases leading to the automation of the mechanical building systems on the Harvard campus are described. The systems allow a single operator to monitor and control all the mechanical systems, plus fire, flood, and security alarms, for all buildings in a large area of the campus. (JT)

Sprague, George W.

414

HOW TO PROVIDE AUTOMATIC FIRE PROTECTION FOR YOUR BUILDING.  

ERIC Educational Resources Information Center

THE ADVANTAGES OF PROMPT FIRE DETECTION IS DISCUSSED WITH RESPECT TO THE NATURE AND COST OF FIRES. EQUIPMENT IS DESCRIBED, AND DIAGRAMS OF INSTALLATIONS OF DETECTION AND ALARM SYSTEMS ARE GIVEN FOR SCHOOLS, HOSPITALS, COMMERICAL BUILDINGS, INDUSTRIAL PLANTS, AND CAMPUSES. (JT)

Honeywell, Inc., Minneapolis, Minn.

415

Jahn-Teller transition of LiMn2O4 studied by x-ray-absorption spectroscopy  

NASA Astrophysics Data System (ADS)

The valence states and local structure of LiMn2O4 have been investigated in comparison with those of ZnMn2O4 and ?-MnO2 by using x-ray-absorption spectroscopy on the Mn K edge, in order to study the Jahn-Teller (JT) transition in LiMn2O4 at Ta=280 K. In the near-edge spectra, a systematic edge shift in accordance with the formal manganese valence was found, confirming the Mn3+/Mn4+ mixed states in LiMn2O4. Extended x-ray-absorption fine structure reveals a structural disorder of MnO6 octahedra in the cubic LiMn2O4 above Ta. The local structure is analyzed using a structural model in which LiMn3+Mn4+O4 consists of isotropic Mn4+O6 octahedra and anisotropic Mn3+O6 octahedra distorted uniaxially by the JT effect. The magnitude of the local JT distortion, the ratio of the longer Mn-O distance to the shorter one, is found to be 1.17 at 300 K, which is as large as that of tetragonal ZnMn2O4 (1.19). The local structure exhibits no change when the temperature is lowered below Ta. These results imply that the low-temperature phase is induced by ordering the local JT distortion.

Yamaguchi, Hirotaka; Yamada, Atsuo; Uwe, Hiromoto

1998-07-01

416

The Several Ages of Learning  

ERIC Educational Resources Information Center

Examines the various stages of human development (as outlined by Erik Erikson and others) with their psychological stresses of recurring crises of identity and expectation and explores some of the implications for education's best serving human needs. Focuses on early childhood, late adolescence, middle age, and old age. (JT)

Bailey, Stephen

1976-01-01

417

The Quebec Health Care System: Its Implication for Medical Education  

ERIC Educational Resources Information Center

Since November 1, 1970, doctors in Quebec have been operating under a government-controlled compulsory and universal "fee-for-service" insurance plan. This article reviews resulting changes and examines implications for medical education of "global medicine," team care, external control of costs, and a new role for the hospital. (Editor/JT)

Des Marchais, Jacques E.

1975-01-01

418

Improved Turbine Disk Design to Increase Reliability of Aircraft Jet Engines.  

National Technical Information Service (NTIS)

An analytical study was conducted on a bore entry cooled turbine disk for the first stage of the JT8D-17 high pressure turbine which had the potential to improve disk life over existing design. The disk analysis included the consideration of transient and...

A. S. Alver J. K. Wong

1975-01-01

419

Evaluation of an Audio Cassette Tape Lecture Course  

ERIC Educational Resources Information Center

An audio-cassette continuing education course (Selected Topics in Pharmacology) from Extension Services in Pharmacy at the University of Wisconsin was offered to a selected test market of pharmacists and evaluated using a pre-, post-test design. Results showed significant increase in cognitive knowledge and strong approval of students. (JT)

Blank, Jerome W.

1975-01-01

420

An Alternative to Anesthetic Learning Climates  

ERIC Educational Resources Information Center

On the premise that the college classroom should heighten, not cool, a zeal for learning, the author proposes that colleges extend the range of alternative paths to personal growth through a program of voluntary temporary learning communities using diverse modes of inquiry. (JT)

Epperson, David C.

1975-01-01

421

The Validity of Warrantless Searches under the Occupational Safety and Health Act of 1970  

ERIC Educational Resources Information Center

One of the most controversial federal acts providing for random administrative searches is the Occupational Safety and Health Act of 1970 (OSHA). The author reviews the search and seizure law and concludes that abandonment of Fourth Amendment rights should not be predicated on the mere convenience of even a justifiable regulatory scheme. (JT)

Shanks, Michael D.

1975-01-01

422

Hoods for Science Laboratories.  

ERIC Educational Resources Information Center

Detailed discussions are presented dealing with the selection and design of fume hoods for science laboratories. Areas covered include--(1) air flow design, (2) materials properties, (3) location in the laboratory, (4) testing and adjustment, (5) exhaust systems, and (6) hazards of fume discharges. (JT)

Horowitz, Harold; and others

423

Social Work in the Police Agency: Implications for Education and Practice  

ERIC Educational Resources Information Center

Issues uncovered in a 3-year action-research project that placed social workers and graduate students in community police departments were selection of staff and students, attitudes about the law, confidentiality, motivating the reluctant client, and sensitivity to police-social worker perceptions of each other. (JT)

Treger, Harvey

1976-01-01

424

Production of Artificial Lightning in An Ordinary Clear Light Bulb.  

ERIC Educational Resources Information Center

Reported is a method of producing artificial lightning in an ordinary clear lightbulb. The appearance of sparks produced is that of a miniature stroke of forked lightning seen in natural thunderstorms. The sparks also show the intricate branching patterns often seen in natural lightning. (JT)

Zaffo, Peter Alfred

1981-01-01

425

Extended region of nodulation genes in Rhizobium meliloti 1021. I. Phenotypes of Tn5 insertion mutants  

SciTech Connect

Rhizobium meliloti Nod/sup -/ mutant WL131, a derivative of wild-type strain 102F51, was complemented by a clone bank of wild-type R. meliloti 1021 DNA, and clone pRmJT5 was recovered. Transfer of pRmJT5 conferred alfalfa nodulation on other Rhizobium species, indicating a role in host range determination for pRmJT5. Mutagenesis of pRmJT5 revealed several segments in which transposon insertion causes delay in nodulation, and/or marked reduction of the number of nodules formed on host alfalfa plants. The set of mutants indicated five regions in which nod genes are located; one mutant, nod-216, is located in a region not previously reported to encode a nodulation gene. Other mutant phenotypes correlated with the positions of open reading frames for nodH, nodF and nodE, and with a 2.2-kb EcoRI fragment. A mutant in nodG had no altered phenotype in this strain. One nodulation mutant was shown to be a large deletion of the common nod gene region. The authors present a discussion comparing the various studies made on this extended nod gene region.

Swanson, J.A.; Tu, J.K.; Ogawa, J.; Sanga, R.; Fisher, R.F.; Long, S.R.

1987-10-01

426

College Stores 1975--A Challenge to the Publishers  

ERIC Educational Resources Information Center

A presentation by the general manager of the Harvard Cooperative Society to the College Division of the Association of American Publishers in which he illustrates with survey data the contention that suggested publishers prices for textbooks are arbitrarily set too low by publishers to cover minimal costs of marketing textbooks. (JT)

Davis, Howard W.

1976-01-01

427

Skills in History-Taking and Physical Examination  

ERIC Educational Resources Information Center

Clerks and house officers in a training program in internal medicine were observed during the performance of a history and physical examination. An itemized evaluation form was used to standardize the observations. Results and implications are discussed including the value of simulation in teaching physical diagnosis skills. (Editor/JT)

Aloia, John F.; Jonas, Ernesto

1976-01-01

428

Predicting loss in magnetic steels under arbitrary induction waveform and with minor hysteresis loops  

Microsoft Academic Search

We have studied ways of predicting power losses in soft magnetic laminations for generic time dependence of the periodic magnetic polarization J(t). We found that, whatever the frequency and the induction waveform, the loss behavior can be quantitatively assessed within the theoretical framework of the statistical loss model. The prediction requires a limited set of preemptive experimental data, depending on

Edoardo Barbisio; Fausto Fiorillo; Carlo Ragusa

2004-01-01

429

A Framework for Academic Planning  

ERIC Educational Resources Information Center

Desired characteristics of the academic process are discussed, including assessment of fundamental values and assumptions, clarification of short-range objectives, the importance of data collection, the determination of institutional priorities and strategies for implementation, and the value of a continuous and open planning process. (Editor/JT)

Fuller, Bruce

1976-01-01

430

Preliminary design study of astronomical detector cooling system  

NASA Technical Reports Server (NTRS)

The preliminary design of an astronomical detector cooling system for possible use in the NASA C-141 Airborne Infrared Observatory is presented. The system consists of the following elements: supercritical helium tank, Joule-Thomson supply gas conditioner, Joule-Thomson expander (JTX), optical cavity dewar, optical cavity temperature controller, adjustable J-T discharge gas pressure controller, and vacuum pump.

Norman, R. H.

1976-01-01

431

A Marketing Plan That Works  

ERIC Educational Resources Information Center

Olivet College's marketing plan included survey of students, alumni, townspeople, and doners and analysis of the college's customer appeal, prices, and product mix. The author reports that the marketing objectives are being met and discusses the rationale and problems of applying business marketing principles to education. (JT)

Sparks, Jack D.

1976-01-01

432

Discharges with high bootstrap current fraction on Tore Supra.  

National Technical Information Service (NTIS)

Bootstrap current is regarded as a serious candidate for non-inductively driving a significant fraction of the total current. High bootstrap fraction discharges have already been achieved and analysed in several tokamaks, including JT-60, DIII-D and TFTR....

E. Joffrin B. Saoutic V. Basiuk C. Forest W. A. Houlberg

1995-01-01

433

Characteristics of a liquid-helium-free calibration apparatus for cryogenic thermometers  

SciTech Connect

Closed-cycle Joule-Thomson (JT) cryocoolers have been developed at National Metrology Institute of Japan (NMIJ)/National Institute of Advanced Industrial Science and Technology (AIST) with the aim of realizing a liquid-helium-free calibration apparatus for cryogenic thermometers between 0.65 K and 25 K. The latest JT cryocooler at NMIJ/AIST consists of a {sup 3}He JT cooling circuit and a pulse tube mechanical refrigerator. The characteristics of the apparatus including a residual gas analysis of the JT cooling circuit are presented in this paper. Currently the initial cool-down is performed using a heat-exchange gas. It normally takes about 30 h to reduce the temperature from room temperature to 5 K at the thermometer comparison block of the apparatus. The correct timing of the removal of the heatexchange gas is important for the efficient operation of the apparatus. Incomplete removal of the heat-exchange gas induces excess heat load on the apparatus and thermal disturbances. Some examples of abrupt temperature bursts are discussed in this paper. Mechanical refrigerators generate cyclic mechanical vibrations, and precision resistance thermometers are usually very sensitive to a mechanical vibration. The measured vibration level of the developed apparatus is reported. The damage to the apparatus due to the magnitude 9.0 earthquake on March 11, 2011, and possible countermeasures in the case of future earthquakes are also discussed.

Shimazaki, T. [National Metrology Institute of Japan, AIST, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)] [National Metrology Institute of Japan, AIST, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)

2013-09-11

434

Toward Sustainable Production of Protein-Rich Foods: Appraisal of Eight Crops for Western Europe. PART I. Analysis of the Primary Links of the Production Chain  

Microsoft Academic Search

Referee: Dr. R. Owusu Apenten, Department of Food Science, The Leeds University, Leeds LS2 9JT, United Kingdom Increased production of plant protein is required to support the production of protein-rich foods that can replace meat in the human diet to reduce the strain that intensive animal husbandry poses to the environment. The suitability of lupin (Lupinus spp.), pea (Pisum sativum),

Anita R. Linnemann; Dolf Swaving Dijkstra

2002-01-01

435

Test-Engine and Inlet Performance of an Aircraft Used for Investigating Flight Effects on Fan Noise.  

National Technical Information Service (NTIS)

As part of the NASA Flight Effects on Fan Noise Program, a Grumman OV-1B Mohawk aircraft was modified to carry a modified and instrumented Pratt & Whitney JT15D-1 turbofan engine. Onboard flight data, together with simultaneously measured farfield acousti...

R. A. Golub J. S. Preisser

1984-01-01

436

Medical Academe and the Problems of Primary Care  

ERIC Educational Resources Information Center

The President of the Robert Wood Johnson Foundation points up the lack of a dependable system of ambulatory front-line medical care in the U.S., outlines basic capabilities of the system needed, and suggests the role of foundations and academic centers in developing training programs recast in light of real world situations. (JT)

Rogers, David E.

1975-01-01

437

Two-stage, low noise advanced technology fan. 5: Acoustic final report  

NASA Technical Reports Server (NTRS)

The NASA Q2S(quiet two-stage) fan is a 0.836m (32.9 in.) diameter model of the STF 433 engine fan, selected in a 1972 study for an Advanced Technology Transport (ATT) airplane. Noise-control features include: low tip speed, moderate stage pressure rise, large blade-vane spacings, no inlet guide vanes, and optimum blade and vane numbers. Tests were run on the baseline Q2S fan with standard inlet and discharge ducts. Further tests were made of a translating centerbody sonic inlet device and treated discharge ducts. Results were scaled to JT8D and JT3D engine fan size for comparison with current two-stage fans, and were also scaled to STF 433 fan size to compare calculated ATT flyover noise with FAR 36 limits. Baseline Q2S results scaled to JT8D and JT3D engine fan sizes showed substantial noise reductions. Calculated unsuppressed baseline ATT flyovers averaged about 2.5 EPNdB below FAR 36 limits. Using measured sonic inlet results, scaled baseline Q2S fan results, and calculated attenuations for a 1975 technology duct liner, projected flyover noise calculations for the ATT averaged about FAR 36 limits minus 10 EPNdB. Advances in suppression technology required to meet the 1985 goal of FAR 36 limits minus 20 EPNdB are discussed.

Sofrin, T. G.; Riloff, N., Jr.

1975-01-01

438

Employee Selection at the University of Houston Libraries  

ERIC Educational Resources Information Center

The development and operation of a successful employee selection, promotion, and transfer program is described. The 3-year program involved posting public notices of all library vacancies, actual or anticipated, and encouraging individuals, whether on the staff or not, to apply for positions in which they were interested. (JT)

Brand, Marvine

1975-01-01

439

Interdisciplinary Education for the Architect  

ERIC Educational Resources Information Center

Architectural education has three choices, according to the author: to seek more collaborative possibilities with the behavioral sciences (multi-disciplinary) to establish a new framework for defining the relationship between man, environment, and built space (the ideal); or to find some medium ground between the two (interdisciplinary). (JT)

McKellar, James

1976-01-01

440

Thermomechanical investigation on divertor supports for fusion experimental reactor: hydraulic experimental results  

Microsoft Academic Search

The Japan Atomic Energy Research Institute has been conducting technology development aimed at the construction of a fusion experimental reactor to follow JT-60 in Japan. The divertor plate facing the plasma is one of the components of the reactor core assembly, since it has to be operated under severe heat and particle loads and high electromagnetic forces. Thus the divertor

T Arai; R Hino; Y Muto; M Nakahira; M Shibui; K Furuya; E Tada; M Seki

1995-01-01

441

The Effect of a Spaced Sex Education Course on Medical Students' Sexual Knowledge and Attitudes  

ERIC Educational Resources Information Center

A testing of 159 first-year medical students who took a spaced sex education course (requiring student participation in a weekly lecture, film, and group discussion) showed significant changes in cognitive knowledge as well as attitudinal tolerance of others but no changes in styles of thinking. Results are related to earlier studies. (JT)

Marcotte, D. B.; And Others

1976-01-01

442

Uncharted Waters: A Preliminary Evaluation of Faculty Attitudes Toward Medical Students  

ERIC Educational Resources Information Center

A study is reported in which faculty evaluated four successive groups of students in relationship to the previous group on seven parameters such as performance, interest, enthusiasm, and response. Results are given supporting the hypothesis that faculty rate students lower early in their clinical rotation when compared with previous students. (JT)

Marcotte, David B.; Manning, Donald E.

1975-01-01

443

Row-Continuous Finite Markov Chains, Structure and Algorithms.  

National Technical Information Service (NTIS)

For any finite bivariate Markov chain J(t), N(t) on state space for which row-continuity is present, i.e., N(t) changes by at most one at transitions, the ergodic distribution and mean passage times may be found by a simple algorithm. Related structure wi...

J. Keilson U. Sumita M. Zachmann

1981-01-01

444

Studies on cooling by liquid helium in a large-scale cryopump of the neutral beam injector and its pumping performances of hydrogen gas and helium gas.  

National Technical Information Service (NTIS)

To develop a large-scale cryopump for hydrogen gas and helium gas in the JT-60 neutral beam injector (NBI), it is necessary to solve two critical issues, i,e., one is stable cooling of the cryopump composed of six cryopanels by liquid helium, and the othe...

K. Shibanuma

1993-01-01

445

Annual report of Naka Fusion Research Establishment for the period from April 1, 1993 to March 31, 1994.  

National Technical Information Service (NTIS)

Research and development activities at Naka Fusion Research Establishment, JAERI, are reported for the period from April 1, 1993 to March 31, 1994. The main objectives of JT-60U experiments in FY1993 were to achieve and sustain high confinement regime wit...

T. Matoba Y. Nakamura Y. Matsuzaki M. Araki Y. Yamane

1995-01-01

446

Modulation of the degree and pattern of methyl-esterification of pectic homogalacturonan in plant cell walls  

Microsoft Academic Search

From the Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom, § Danisco Biotechnology, Langebrogade 1, DK 1001 Copenhagen K, Denmark, Danisco Cultor, Edwin Rahrs Vej 38, DK-8220 Brabrand, Denmark, the ** Department of Agrotechnology and Food Sciences, Laboratory of Food Chemistry, Wageningen University, Bomenweg 2, 6703 HD Wageningen, The Netherlands, and the Procter Department of Food

W. G. T. Willats; C. Orfila; G. Limberg; H. C. Buchholt; Alebeek van G. J. W. M; A. G. J. Voragen; S. E. Marcus

2001-01-01

447

National Education Trust Fund  

ERIC Educational Resources Information Center

A proposal from the governor of Pennsylvania for financing all levels of education through a National Education Trust Fund (NETF) that would operate as the present Federal Highway Trust Fund does on a revolving, self-liquidating basis with the cost of an individual's education repaid through a progressive education tax on income. (JT)

Shapp, Milton J.

1975-01-01

448

Teachers' Freedom of Expression Outside the Classroom: An Analysis of the Application of Pickering and Tinker  

ERIC Educational Resources Information Center

Two Supreme Court cases are analyzed with reference to lower court decisions and their implications: Pickering v. Board of Education, which concerned teachers' expression outside the school, and Tinker v. Des Moines Independent Community School District, which involved students' expression inside the classroom. (JT)

Miller, Simon A.

1974-01-01

449

Evaluation of the Spring Finger Solder Joints on SA1358-10 and SA2052-4 Connector Assemblies (MC3617, W87).  

National Technical Information Service (NTIS)

The SA1358-10 and SA2052-4 circular JT Type plug connectors are used on a number of nuclear weapons and Joint Test Assembly (JTA) systems. Prototype units were evaluated for the following specific defects associated with the 95Sn-5Sb (Sn-Sb, wt.%) solder ...

A. C. Kilgo G. L. Zender P. F. Hlava P. T. Vianco

2006-01-01

450

Forward Velocity Effects on Fan Noise and the Suppression Characteristics of Advanced Inlets as Measured in the NASA-Ames 40 by 80 Foot Wind Tunnel.  

National Technical Information Service (NTIS)

Forward velocity effects on the forward radiated fan noise and on the suppression characteristics of three advanced inlets relative to a baseline cylindrical inlet were measured in the NASA Ames Research Center 40 x 80 foot Wind Tunnel. A modified JT15D t...

M. T. Moore

1980-01-01

451

Prediction of sound radiation from different practical jet engine inlets  

Microsoft Academic Search

Computer codes, capable of producing accurate results for nondimensional wave numbers (based on duct radius) of up to 20, were developed and used to generate results for various other inlet configurations. Both reflection coefficients and radiation patterns were calculated by the integral solution procedure for the following five inlet configurations: the NASA Langley Bellmouth, the NASA Lewis JT-15D-1 ground test

B. T. Zinn; W. L. Meyer

1981-01-01

452

The Reverend Thomas Jefferson Bowen: An Introductory Background to His Linguistic Works, 1850-1856  

ERIC Educational Resources Information Center

A historical narrative background for the linguistic works of Thomas Jefferson Bowen, an American missionary who was the first non-Nigerian to publish a grammar of Yoruba (1858). The author points up a need for further scholarly review of Bowen's pioneering work and contribution to Yoruba studies. (JT)

Awoniyi, Timothy A.

1974-01-01

453

Annual Report of the Naka Fusion Research Establishment for the Period of April 1, 1987 to March 31, 1988.  

National Technical Information Service (NTIS)

Research and development activities of the Naka Fusion Research Establishment for the period of April 1987 to March 1988 are described. In JT-60, the plasma heating experiment aiming at a reactor-grade plasma was started in June 1987, after completing the...

1988-01-01

454

The CUNY Experience  

ERIC Educational Resources Information Center

The Vice-Chancelor for Administration of the City University of New York (CUNY) gives an anecdotal account of the experience at CUNY, the first major university to negotiate and enter into a contractual relationship with its faculty. Emphasis is on the problems encountered, their ultimate resolution, and questions that remain unresolved. (JT)

Mintz, Bernard

1971-01-01

455

Testing Advanced Distributed Simulation for Use in Electronic Warfare Test and Evaluation.  

National Technical Information Service (NTIS)

The JADS JT&E program is an OSD sponsored Joint-Service test designed to determine how well an emerging technology - Advanced Distributed Simulation (ADS) - can support DoD test and evaluation (T&E) activities. The two-phase ADS test using an Electronic W...

D. Wright C. Harris

1998-01-01

456

Law School Stress and the "Deformation Professionelle"  

ERIC Educational Resources Information Center

Evidence from various psychological, sociological, and informal group studies is examined to determine psychological, emotional, and moral effects of legal training. Results show no proof that claimed personality changes exist and (if they do) that they are a result of stress. Conclusions suggest no changes in legal education. (JT)

Taylor, James B.

1975-01-01

457

Unraveling atomic positions in an oxide spinel with two Jahn-Teller ions: local structure investigation of CuMn2O4.  

PubMed

At first sight, the quenched tetragonal spinel CuMn(2)O(4) can be formulated with Cu(2+) and Mn(3+), implying that the tetrahedral site is Jahn-Teller (JT)-active Cu(2+) and the octahedral site is JT-active Mn(3+). High-resolution, high-momentum-transfer neutron scattering analysis suggests that the sample has approximately 30% inversion: Mn on the tetrahedral Cu site with compensating Cu on the octahedral site. Reverse Monte Carlo (RMC) analysis of the pair distribution function allows details of metal-oxygen connectivity to be probed in a manner that is significantly on the local rather than the average scale. Bond valence analysis of the RMC supercell reveals that both JT ions disproportionate to higher and lower valence states as a means of avoiding their JT tendency, particularly on the tetrahedral site. The occurrence of Cu(3+) in particular is suggested for the first time and is supported by X-ray photoelectron spectroscopy data. The bimodal distribution of O-Cu-O bond angles at the tetrahedral site (distinct from what is seen for O-Mn-O bond angles) further reveals a hidden distinction between sites previously considered to be equivalent. Application of total scattering techniques originally developed for highly disordered materials permits the examination of nanoscale crystalline structure with elemental specificity that is not available in traditional reciprocal-space analysis. PMID:19627083

Shoemaker, Daniel P; Li, Jun; Seshadri, Ram

2009-08-19

458

Assessing Competence in Pediatric Cardiology  

ERIC Educational Resources Information Center

In response to the need to assure physician competence, a rating scale was developed at the University of Minnesota Medical School for use in evaluating clinical competence in pediatric cardiology. It was tested on first- and second-year specialists. Development and testing procedures are described. (JT)

Johnson, Apul E.; And Others

1976-01-01

459

Extraction physics in volume H--ion sources  

Microsoft Academic Search

Recent hydrogen negative-ion sources (JT60, large helical device (LHD)) operate with a magnetic filter field extending up to the plasma electrode and extraction opening. As shown earlier such a magnetic field has a strong effect upon the value of the extracted negative ion and electron current. Measurements of the negative ion and electron density were performed in the ion source,

M. Bacal; A. Hatayama; T. Matsumiya; M. Hamabe; T. Kuroda; Y. Oka

2006-01-01

460

The International Thermonuclear Experimental Reactor (ITER) International Organisation: Which Laws Apply to this International Nuclear Operator?  

Microsoft Academic Search

ITER is a research project the purpose of which is to demonstrate the scientific and technical feasibility of fusion as a new source of energy. After construction of large Tokamaks,1 such as the JT60 in Japan, TFTR (Tokamak Fusion Test Reactor) in the United States, JET (Joint European Torus) in the United Kingdom and Tore Supra in France, this project

Laetitia Grammatico-Vidal

2009-01-01

461

FIRST PRINCIPLES CALCULATIONS OF TOKAMAK ENERGY TRANSPORT  

Microsoft Academic Search

FIRST PRINCIPLES CALCULATIONS OF TOKAMAK ENERGY TRANSPORT. A predictive, physics based model of tokamak energy transport that is based on simulations of the gyrokinetic equation is presented. Calculations of core energy transport are compared with experimental results from JET, TFTR, JT60-U and DIII-D for a variety of discharge conditions. In the region of the plasma predicted to be unstable to

M. KOTSCHENREUTHER; W. DORLAND; Q. P. LIU; G. W. HAMMETT; M. A. BEER; S. A. SMITH; A. BONDESON

462

Highlights from the Jet Stability Programme  

Microsoft Academic Search

An overview of the JET stability programme is given, highlighting the latest results: New halo current detectors confirm ITER scaling assumptions. Runaway electrons appear above 2T, as in JT60, and are dominantly due to avalanche processes. Disruption mitigation with neutral point operation and impurity puffing has been demonstrated. Scaling of NTM metastable thresholds and physics of FIR-NTM mitigation have been

S. D. Pinches; R. J. Buttery; T. C. Hender

2003-01-01

463

Pedestal Scaling with Global Plasma Parameters in NSTX  

Microsoft Academic Search

A successful mode of operation of ITER will require establishing sufficiently high pedestal pressure during H-mode discharges as well as small or no ELMs. Recent observations from high aspect ratio tokamaks (DIIID, ASDEX, JT60) have shown a general trend in the pedestal pressure and density widths scaling with the pedestal poloidal beta (beta) to the power one half The low

A. Diallo; R. Maingi; J. Menard; S. Zweben; B. Leblanc; R. Maqueda; B. Stratton; D. Smith; Y. Ren; S. Kubota

2010-01-01

464

The physics of production, acceleration and neutralization of large negative ion beams  

Microsoft Academic Search

Neutral beam systems for the next generation of magnetic fusion devices will be based on negative ions. Developments are progressing steadily, and large negative ion-based systems are under preparation for JT60-U and LHD, and are being considered for ITER. An overview of the physics of the production, acceleration and neutralization of large negative ion beams is given. The present state

J. Pamela

1995-01-01

465

Scaling radiative plasmas to ITER  

Microsoft Academic Search

In the radiative regime non-intrinsic impurities have been used to produce divertor power loads which would be considered acceptable when extrapolated to ITER. However, it has been a matter of concern that the maximum Zeff currently deemed acceptable for ITER has been exceeded by a large margin in radiative plasma experiments in large divertor machines such as JET, JT60-U, AUG

G. F. Matthews; S. Allen; N. Asakura; J. Goetz; H. Guo; A. Kallenbach; B. Lipschultz; K. McCormick; M. Stamp; U. Samm; P. C. Stangeby; K.-H. Steuer; A. Taroni; B. Unterberg

1997-01-01

466

A Couples Group of Medical Students  

ERIC Educational Resources Information Center

An experiment at the Albert Einstein College of Medicine with a short-term medical student couples' workshop designed to foster increased sensitivity between medical students and their partners resulted in recommendation that such workshops be offered to medical students. (JT)

Porter, Kenneth; And Others

1976-01-01

467

Teaching Blood Gases: An Automated Display  

ERIC Educational Resources Information Center

Use of sequential data display on the Davenport diagram mated with computer techniques offers solutions to both data storage and teaching problems related to blood gas determinations. An example of using the technique for teaching interpretation of data to medical students is given. (JT)

Bailey, William; And Others

1976-01-01

468

Breadwinning, Books, and Beauty at BU  

ERIC Educational Resources Information Center

Boston University's Program in Artisanry, begun in January 1975, blends the vocational, manual and artistic within a liberal arts system. Philosophy, staff, and curriculum are described for the craft school which has 73 majors who take one-third of their courses from the larger University. (JT)

Kay, Jane Holtz

1976-01-01

469

Diagonal Conditions in Ordered Spaces  

Microsoft Academic Search

For a space X and a regular uncountable cardinal jXj we say that 2 D(X) if for each T X 2 ( X) with jTj = , there is an open neighborhood W of ( X) such that jT Wj = . If !12 D(X) then we say that X has a small diagonal, and if every regular uncountable j

Harold R Bennett; David J. Lutzer

470

Cryogenic recondenser with remote cold box  

Microsoft Academic Search

This patent describes a cryogenic recondenser for recondensing cryogen retained in a storage vessel. The recondenser consists of: cooling means comprising a mechanical refrigerator positioned outside of the storage vessel, the means precooling a volume of gaseous refrigerant; a transfer line leading from the cooling means and removeably inserted into the storage vessel; and a JT valve at an end

A. J. Bartlett; B. R. Andeen; P. A. Lessard

1988-01-01

471

A highly efficient 100 L\\/HR class helium liquefier system  

Microsoft Academic Search

A new helium liquefier system has been designed and built to provide over 100 liters per hour with a highly efficient process cycle. The modified Claude-cycle utilizes four reciprocating piston expansion engines configured in series, with the lowest temperature engine acting as a wet expander (replacing the usual JT valve). Operation of the system is highly flexible, permitting the use

Thomas Ankermann; Roberto Than; Hank Valcour

1994-01-01

472

Performance of a MEMS Heat Exchanger for a Cryosurgical Probe  

Microsoft Academic Search

This paper presents the experimental test results for two 2 nd generation Micro-Electro- Mechanical Systems (MEMS) heat exchangers that are a composite of silicon plates with micro- machined flow passages interleaved with glass spacers. The MEMS heat exchangers were designed for use as the recuperative heat exchanger within a Joule-Thomson (JT) cycle used to energize a cryosurgical probe. The heat

M. J. White; W. Zhu; G. F. Nellis; S. A. Klein; Y. B. Gianchandani

473

Details of the Cryogenic System for the Cornell Superconducting RF Beam Tests  

Microsoft Academic Search

During the course of the most recent and past Superconducting R.F. beam tests in CESR, various techniques and concepts were developed in the implementation of the cryogenic system. Some of these items are described and include the long liquid helium transfer line, the liquid phase separation, the liquid nitrogen cooling system, feeding the wavequide heat exchangers, the JT valve, the

J. Kirchgessner; P. Demjanic; C. Henderson; S. Herb; N. Mistry; L. Phillips; J. Walters

1985-01-01

474

Cryocooler  

Microsoft Academic Search

Ball Aerospace and Redstone Engineering together have designed, built, and are currently assembling a hybrid cryocooler tailored for cooling infrared imaging systems that have variable loads. The system is a hybrid of complementary Stirling and Joule-Thomson (JT) cycle cryocoolers. It is based on Ball's efficient two stage Stirling cycle cryocooler, the SB235E, which provides the bulk of the refrigeration. It

W. Gully; P. Hendershott; D. Glaister; J. Lester; R. Levenduski; E. Marquardt

475

Cryogenic recondenser with remote cold box  

SciTech Connect

This patent describes a cryogenic recondenser for recondensing cryogen retained in a storage vessel. The recondenser consists of: cooling means comprising a mechanical refrigerator positioned outside of the storage vessel, the means precooling a volume of gaseous refrigerant; a transfer line leading from the cooling means and removeably inserted into the storage vessel; and a JT valve at an end of the transfer line in the storage vessel, the precooled refrigerant being transferred in the transfer line from the cooling means to the JT valve in heat exchange relation with returning refrigerant and being expanded through the JT valve to form a liquid-gas cryogen mixture within the end of the transfer line which is in heat exchange relation with boil-off from the cryogen retained in the storage vessel such that the boil off is cooled and recondensed; refrigerant being returned to the cooling means through the transfer line in a manner in which the returning refrigerant is in heat exchange relation with the refrigerant being transferred to the JT valve.

Bartlett, A.J.; Andeen, B.R.; Lessard, P.A.

1988-08-30

476

Microchannel heat exchanger for two-phase Mixed Refrigerant Joule Thomson process  

NASA Astrophysics Data System (ADS)

Mixed Refrigerant Joule Thomson (MR-JT) refrigerators are widely used in various kinds of cryogenic systems these days. Printed Circuit Heat Exchanger (PCHE) is one of the promising cryogenic compact recuperators for MR-JT refrigerators due to its compactness, high NTU and robustness. However, PCHE composed with microchannel bundles can cause flow mal-distribution, and it can cause the degradation of thermal performance of the system. To mitigate the flow mal-distribution problem, the cross link (or intra-layer bypass) can be adapted to parallel microchannels. Two heat exchangers are fabricated in this study; one has straight channels, and the other one has intra-layer bypass structure between channels to enhance the flow distribution. The MR-JT refrigerators are operated with these two heat exchanger and the no-load temperatures are compared. The lower no load temperature achieved with the intra-layer bypass structured heat exchanger. The results indicate that the flow mal-distribution in the microchannel heat exchanger can be mitigated with intra-layer bypass structure, and relaxation of flow mal-distribution in the heat exchanger guarantee the MR-JT refrigerator's performance.

Baek, Seungwhan; Lee, Jisung; Lee, Cheonkyu; Jeong, Sangkwon

2014-01-01

477

Minicalculators and Repeating Decimals  

ERIC Educational Resources Information Center

An algorithm is provided for generating as many desired digits in the decimal representation of a rational number on a calculator. It may be used whenever the number of digits displayed on the calculator exceeds the number of digits in the denominator. (JT)

Burris, Charles H.; Hobbs, Billy F.

1978-01-01

478

ATMOSPHERIC CONCENTRATIONS OF AMMONIA AND AMMONIUM AT AN AGRICULTURAL SITE IN THE SOUTHEAST UNITED STATES: JOURNAL ARTICLE  

EPA Science Inventory

NRMRL-RTP-P-611 Robarge, W.P., Walker*, J.T., McCulloch, R.B., and Murray, G. Atmospheric Concentrations of Ammonia and Ammonium at an Agricultural Site in the Southeast United States. Atmospheric Environment 36 (10):1661-1674 (2002). 06/18/2001 In this study, we present app...

479

Neutron Emission Profile And Neutron Spectrum Measurements At JET: Status And Plans  

Microsoft Academic Search

In large tokamak devices, such as JET, TFTR, JT-60U and ITER, a neutron emission profile monitor is considered as one of the principal diagnostic tools, firstly in providing information to characterize the fusion source in terms of its location, shape, intensity and secondly in developing an understanding of fast ion physics in tokamak plasmas. The JET neutron profile monitor is

S. Popovichev; L. Bertalot; F. Belli; G. Bonheure; S. Conroy; A. Hjalmarsson; G. Ericsson; B. Esposito; J. Källne; V. Kiptily; D. Marocco; A. Murari; M. Riva; B. Syme; M. Tsalas; M. Weiszflog; JET EFDA contributors

2008-01-01

480

Characteristics of a liquid-helium-free calibration apparatus for cryogenic thermometers  

NASA Astrophysics Data System (ADS)

Closed-cycle Joule-Thomson (JT) cryocoolers have been developed at National Metrology Institute of Japan (NMIJ)/National Institute of Advanced Industrial Science and Technology (AIST) with the aim of realizing a liquid-helium-free calibration apparatus for cryogenic thermometers between 0.65 K and 25 K. The latest JT cryocooler at NMIJ/AIST consists of a 3He JT cooling circuit and a pulse tube mechanical refrigerator. The characteristics of the apparatus including a residual gas analysis of the JT cooling circuit are presented in this paper. Currently the initial cool-down is performed using a heat-exchange gas. It normally takes about 30 h to reduce the temperature from room temperature to 5 K at the thermometer comparison block of the apparatus. The correct timing of the removal of the heatexchange gas is important for the efficient operation of the apparatus. Incomplete removal of the heat-exchange gas induces excess heat load on the apparatus and thermal disturbances. Some examples of abrupt temperature bursts are discussed in this paper. Mechanical refrigerators generate cyclic mechanical vibrations, and precision resistance thermometers are usually very sensitive to a mechanical vibration. The measured vibration level of the developed apparatus is reported. The damage to the apparatus due to the magnitude 9.0 earthquake on March 11, 2011, and possible countermeasures in the case of future earthquakes are also discussed.

Shimazaki, T.

2013-09-01